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https://openalex.org/W2955024071
https://europepmc.org/articles/pmc6610858?pdf=render
English
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Evidence of perpetration of intimate partner violence among HIV-positive couples: a systematic scoping review protocol
Systematic reviews
2,019
cc-by
3,847
Evidence of perpetration of intimate partner violence among HIV-positive couples: a systematic scoping review protocol Felix Apiribu1,2* , Busisiwe Purity Ncama1 and Elizabeth Joseph-Shehu1,3 Abstract The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated * Correspondence: fapiribu.chs@knust.edu.gh 1School of Nursing and Public Health, College of Health Sciences, University of KwaZulu-Natal, Desmond Clearance Building, Howard College Campus, Durban 4001, South Africa 2Department of Nursing, Faculty of Allied Health Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana Full list of author information is available at the end of the article * Correspondence: fapiribu.chs@knust.edu.gh Apiribu et al. Systematic Reviews (2019) 8:159 https://doi.org/10.1186/s13643-019-1051-3 Apiribu et al. Systematic Reviews (2019) 8:159 https://doi.org/10.1186/s13643-019-1051-3 Abstract Background: Human immunodeficiency virus (HIV) infection and intimate partner violence (IPV) remain highly sensitive areas that have issues to do with stigmatization in many African countries. Despite the fact that there are several studies on the prevention of HIV, the prevalence of HIV in many African countries is still high. Literature shows that prevention of intimate partner violence is key in the spread of HIV infection. This study will focus on evidence of experiences of HIV positive couples with intimate partner violence and the types of violence experienced. This scoping review will map information about intimate partner violence in low- and middle-income countries as well as other countries with intimate partner violence. There is the need to review these studies on HIV positive couples with intimate partner violence to establish gaps and identify where primary research is necessary. The purpose of this study will be to explore evidence of experiences of HIV-positive couples with IPV and the types of violence experiences by HIV-positive couples. Methods: This scoping review will involve electronic databases, which will include academic search premier, CINAHL, PsycARTICLES (EBSCO), PsycINFO (EBSCO), ScienceDirect, PubMed, MEDLINE (EBSCO) and Google Scholar. The study will be conducted in two stages: the first stage will map out the studies descriptively while the second stage will map the additional inclusion criteria of quality assessment. Two independent reviewers will undertake the data extraction. Relevant outcomes of the studies will be analyzed thematically using NVivo computer software. Results: Results on the evidence of the experiences of HIV-positive couples with partner violence will be coded independently by the authors. Thereafter, the authors will critically cross-examine the relationship of the research questions to the emerging themes from the selected articles. Conclusion: The authors hope to find studies on intimate partner violence among HIV-positive couples to establish gaps where primary research will be necessary. Systematic review registration: PROSPERO CRD42017062190 Systematic review registration: PROSPERO CRD42017062190 Keywords: Intimate partner violence, HIV/AIDS, Couples, Disclosure, Behaviour, Low- and middle-income countries Keywords: Intimate partner violence, HIV/AIDS, Couples, Disclosure, Behaviour, Low- and middle-income countries © The Author(s). 2019 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Background countries [14] which are low- and middle-income countries. Therefore, the need to review studies on HIV-positive couples with intimate partner violence to establish gaps and identify where primary research is necessary. Hence, this study will explore evidence of experiences of HIV-positive couples with IPV and the types of violence experiences by HIV-positive couples. Intimacy issues in relationships are normally very sensi- tive and secretive especially when they are related to hu- man immunodeficiency virus (HIV) disclosure. Although a lot of work has been done to either minimize it or eliminate it completely as much as possible, fear, ignor- ance and discrimination regarding HIV continue to exact profound human costs like abusive treatment and vio- lence [4, 16, 18]. Spangenberg et al. identified that 46% of mothers of sick newborns in Ghana reported some form of violence. Women who are HIV positive are at risk of experiencing the same forms of violence as other women in the population but in a severe form because of their status [17]. Research objectives The main aim of the review is to explore evidence of in- timate partner violence among human immunodefi- ciency virus (HIV)-positive couples. The specific objectives of the study include the following: There is increasing evidence suggesting that HIV- positive women and probably men in many African countries may be at increased risk of experiencing intim- ate partner violence (IPV) following disclosure of their status to their partners [3, 12, 14]. These problems relat- ing to IPV are, however, more likely to be exacerbated in resource-poor settings like Ghana, where discrimination and stigmatization are high [2, 3]. HIV-positive couples in such areas are at risk of being ostracized, denied some essential services, criticized, thrown out of their homes, divorced and/or blamed for bringing disease into the family or into the community [15]. Shamu et al. further reported that 40.5% of HIV-positive pregnant women in Zimbabwe experienced IPV after disclosure of their HIV-positive status to their partners. HIV-positive women are at increased risk of experiencing IPV follow- ing disclosure of the partner’s status to each other [1, 10]. The fear of IPV (physical, sexual, psychological and spiritual abuse) may decrease HIV-prevention behav- iours [5, 8, 15] such as disclosure of seropositive status to partners, which may lead to the spread of the infec- tion. It may also prevent HIV-positive couples from stay- ing on lifelong antiretroviral treatment and prevention of mother-to-child transmission [6, 7, 13]. Violence against HIV-positive women also has a consequential in- fluence on status disclosure, which is vital to HIV pre- vention and partner support in accessing preventive services [8, 9]. 1. To review evidence on the types of intimate partner violence among HIV couples g p 2. To review evidence on the experiences of HIV couples with intimate partner violence The study will provide answers to the following questions: 1. What are the types of intimate partner violence among HIV couples? 2. What are the experiences of HIV couples with intimate partner violence? 2. What are the experiences of HIV couples with intimate partner violence? © The Author(s). 2019 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Page 2 of 5 Apiribu et al. Systematic Reviews (2019) 8:159 Page 2 of 5 Apiribu et al. Systematic Reviews (2019) 8:159 Apiribu et al. Systematic Reviews Search strategy and study selection This scoping review will involve electronic databases which will include PsycARTICLES (EBSCO), Psy- cINFO (EBSCO), ScienceDirect, PubMed, MEDLINE (EBSCO) and Google Scholar. The search strategy will include all studies that addressed evidence of experi- ences of HIV-positive couples with partner violence. All peer-reviewed studies and grey literature that ad- dresses the research questions will be selected in the study. Only articles published in English between 2007 and 2018 will be used. The reason for limiting this study to between 2007 and 2018 is due to lack of resources. The literature search results will be uploaded to EndNote X8. The EndNote X8 software will be used to find and remove duplicates. The search will be conducted over 4 months. Intimate partner violence by men against their part- ners is one of the most glaring indicators of women’s lack of empowerment [3, 10]. There is often the need for the collection of both victimization and offending data that question both partners. This would allow for an examination of the association between status compati- bilities and intimate partner violence and victimization and perpetration, as well as mutually combative behav- iour between intimate partners [11]. Methods/designs This study protocol was registered and published with the International Prospective Register of Systematic Reviews (PROSPERO) with registration number CRD42017062190. Data extraction Numerical summary and thematic analysis will be employed to extract background information from the selected studies. In order to answer the research ques- tions as guided by population, interventions, comparison and outcome (PICOS) (Table 1), the reviewers will col- lectively design a data-chronicling form to determine the text words, and themes to include and extract. They will also collectively develop the data-charting form. ➢Review articles including systematic reviews, meta- analysis, scoping reviews, peer-reviewed journal articles and rapid reviews ➢Information and data relevant to answer the research questions will be determined by the reviewers collectively ➢Grey literature sources such as documents from government and non-governmental organizations and academic dissertations ➢All types of study designs such as cohort studies, cross-sectional studies, qualitative studies, quantitative studies, randomized control trial studies, quasi- experimental study designs and pilot studies ➢Update recording of data relevant to the study ➢Relevant data will be extracted from all the eligible studies by two independent reviewers in duplicate Data to be extracted include (i) author (s) names, (ii) year of publication, (iii) study design and/or method- ology, (iv) study population, (v) intervention(s), (vi) study setting, (vii) aim of the study, (viii) geographic lo- cation of the study and (ix) conclusions. Criteria for inclusion There is scarcity of evidence on the most effective ways of reducing IPV and abuse among persons living with HIV (PLWHIV) in most sub-Saharan African ➢Articles published in the English language ➢Articles published in the English language Apiribu et al. Systematic Reviews (2019) 8:159 Page 3 of 5 Page 3 of 5 ➢Literature published from January 2007 to December 2018 ➢Articles that report on experiences of couples with HIV ➢Evidence from published relevant literatures ➢Studies reporting on experiences of intimate partner violence ➢Review articles including systematic reviews, meta- analysis, scoping reviews, peer-reviewed journal articles and rapid reviews ➢Grey literature sources such as documents from government and non-governmental organizations and academic dissertations ➢All types of study designs such as cohort studies, cross-sectional studies, qualitative studies, quantitative studies, randomized control trial studies, quasi- experimental study designs and pilot studies ➢Literature published from January 2007 to December 2018 ➢Articles that report on experiences of couples with HIV ➢Evidence from published relevant literatures ➢Studies reporting on experiences of intimate partner violence ➢Review articles including systematic reviews, meta- analysis, scoping reviews, peer-reviewed journal articles and rapid reviews ➢Grey literature sources such as documents from government and non-governmental organizations and academic dissertations ➢All types of study designs such as cohort studies, cross-sectional studies, qualitative studies, quantitative studies, randomized control trial studies, quasi- experimental study designs and pilot studies Exclusion criteria ➢Intervention that does not include any form of intimate partner violence ➢Studies not focusing on experiences of HIV-positive couples with intimate partner violence and approaches to reducing its prevalence Information specific to the evidence of experiences of HIV-positive couples with partner violence will be ex- tracted using phases of the literature search for extrac- tion of the most specific literature for the review as seen in Fig. 1 below. ➢Studies reporting on other infections other than human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) ➢If necessary, a third reviewer will be consulted in order to reach consensus ➢If necessary, a third reviewer will be consulted in order to reach consensus ➢Non-English publications ➢Articles published before January 2007 and after December 2018 ➢The researchers will collectively carry out a thematic analysis to extract relevant outcomes using NVivo software ➢The researchers will collectively carry out a thematic analysis to extract relevant outcomes using NVivo software ➢Articles not focusing on HIV-positive adults in intimate relationship. Keywords search (Table 1) will be combined into a phrase including Boolean (AND, OR) terms, as follows: (intimate partner violence AND HIV/AIDS OR couples OR disclosure OR behaviour OR low and middle income countries). Patient and public involvement p Patients and/or the public were not involved in this study. Findings from this study will contribute to the body of knowledge on intimate partner violence among HIV- positive individual/couples which will have a positive im- pact on research, practice and policy. Reduction or elim- ination of intimate partner violence should help improve the quality of life of HIV-positive couples and increase their life expectancy. The findings from the study will provide an insight on the possible means of reducing IPV and abuse among PLWHIV. llating, summarizing and communicating results The main aim of this review is to scope for existing evi- dence of the experiences of HIV-positive couples with partner violence and summarize the findings as pre- sented across the articles reviewed. The research team will meet to carry out a thematic analysis of the data col- lected and provide an overview of all data collected. This process will include the following steps; Updated records of the number of publications identi- fied during each session of the literature search will be kept using the information. Table 1 A PICOS framework for determination of the eligibility of the review question Criteria Determinants Population The population of the study will be individuals in intimate relationship and living with HIV Interventions Intimate partner violence Comparisons None Outcomes Promote positive relationship among HIV couples, prevent the spread of HIV and improve quality of life (general well-being and health) Study settings Low- and middle-income countries are the focus. Owing to the scarcity of literature on intimate partner violence, we proposed not to limit the scope of this review by study setting. The rationale for this is to have a good number of publications globally for comparison Table 1 A PICOS framework for determination of the eligibility of the review question Criteria Determinants Table 1 A PICOS framework for determination of the eligibility of the review question Page 4 of 5 Page 4 of 5 Apiribu et al. Systematic Reviews (2019) 8:159 Apiribu et al. Systematic Reviews Step 1: Examine the bibliographic details, study designs, number of participants, study setting and funding sources of all included studies Step 1: Examine the bibliographic details, study designs, number of participants, study setting and funding sources of all included studies HIV populations in low- and middle-income countries while campaigns have further slowed the spread of the virus. However, these efforts are being hindered by non- disclosure of HIV-seropositive status by some couples for fear of being victims of intimate partner violence. Good intimate partner relationship can improve the quality of life of HIV-positive couples and increase their life expectancy. IPV prevention can contribute im- mensely on the prevention of HIV/AIDs. Step 2: Results on the evidences of the experiences of human immunodeficiency virus (HIV)-positive couples with partner violence will be coded independently by the authors. llating, summarizing and communicating results All the authors will then come together and interrogate the resultant themes, critically look at their relationship to the set research questions Step 3: The research team will examine the implications for future research, practice and policy based on the main aim of the study We are not aware if there are any empirical studies or reviews that have been done in sub-Saharan African countries that answer the research questions outlined in this protocol. Therefore, this study will include all stud- ies from anywhere in the world that address the popula- tion of interest, intervention and any/or all the outcomes listed in Table 1. Discussion/conclusion This study will generate evidence that will help to de- scribe experiences of human immunodeficiency virus (HIV)-positive individuals/couples with intimate partner violence. Recent improvements in antiretroviral therapy, coupled with nutritional supplementation, have contrib- uted to longevity of life of persons living with HIV (PLWHIV). Mortality and morbidity are now low in Fig. 1 A flow chart showing phases of the literature search for extraction of the most specific literature for the review Fig. 1 A flow chart showing phases of the literature search for extraction of the most specific literature for the review Page 5 of 5 Apiribu et al. Systematic Reviews (2019) 8:159 Page 5 of 5 Apiribu et al. Systematic Reviews (2019) 8:159 Apiribu et al. Systematic Reviews (2019) 8:159 The proposed systematic scoping review results will generate findings that will describe the experiences of HIV-positive couples with partner violence, and the types of violence these populations experienced. The findings from this study will help in identifying gaps in literature on the care of the HIV-positive couples with partner violence. It will also enhance HIV prevention that can be used in education, clinical practice and in making public health policies on HIV and AIDS preven- tion. The gaps identified will help outline areas for pre- ventive strategies to stimulate cordial coexistence among couples in the low- and middle-income countries. How- ever, there is no data on intimate partner violence among HIV-positive couples in low- and middle-income countries. A number of studies have been on HIV and stigmatization among both men and women. Received: 21 December 2018 Accepted: 26 May 2019 Funding Funding There was no funding of the manuscript. 15. Shamu S, Zarowsky C, Shefer T, Temmerman M, Abrahams N. Intimate partner violence after disclosure of HIV test results among pregnant women in Harare, Zimbabwe. PLoS One. 2014;9(10):e109447. 15. Shamu S, Zarowsky C, Shefer T, Temmerman M, Abrahams N. Intimate partner violence after disclosure of HIV test results among pregnant women in Harare, Zimbabwe. PLoS One. 2014;9(10):e109447. Acknowledgements This protocol is supported by the College of Health Sciences, School of Nursing and Public Health, University of KwaZulu-Natal, Durban, South Africa. This gesture is greatly appreciated. 9. Jewkes RK, Levin J, Penn-Kekana LA. Gender inequalities, intimate partner violence and HIV preventive practices: findings of a South African cross sectional study. Soc Sci Med. 2003;56:125–34. 10. Joseph-Shehu EM, Ncama BP. Evidence on health-promoting lifestyle practices and information and communication technologies: scoping review protocol. BMJ Open. 2017;7:1–4. Abbreviations AIDS A i d i AIDS: Acquired immune deficiency syndrome; HIV: Human immunodeficiency virus; HIV/AIDS: Human immunodeficiency virus/acquired immune deficiency syndrome; IPV: Intimate partner violence; PICO: Population, interventions, comparison, and outcome; PLWHIV: Persons living with the human immunodeficiency virus 7. Hatcher AM, Romito P, Odero M, Bukusi EA, Onono M, Turan JM. Social context and drivers of intimate partner violence in rural Kenya: implications for the health of pregnant women. Cult Health Sex. 2013;15(4):404–19. https://doi.org/10.1080/13691058.2012.760205. 7. Hatcher AM, Romito P, Odero M, Bukusi EA, Onono M, Turan JM. Social context and drivers of intimate partner violence in rural Kenya: implications for the health of pregnant women. Cult Health Sex. 2013;15(4):404–19. https://doi.org/10.1080/13691058.2012.760205. 8. Heath and development information team (2003). HIV and AIDS Key Issues Guide; The links between violence against women and HIV and AIDS. http://www.hivpolicy.org/Library/HPP001388.pdf. Authors’ contributions FA contributed to the conception and generation of the review, planning, conduction, analysis and interpretation of the data as well as the design and together with EJS wrote the manuscript. BPN reviewed the manuscript thoroughly and gave administrative support and advice. EJS performed the conduction, analysis and interpretation of the data together with FA. All authors read and approved the final manuscript. 11. Kaukinen C. Status compatibility, physical violence, and emotional abuse in intimate relationships. J Marriage Fam. 2004;66:452–71. 12. Maman S, Campbell J, Sweat MD, Gielen AC. The intersections of HIV and violence: directions for future research and interventions. Soc Sci Med. 2000; 50(4):459–78. 13. Oduro AD, Deere CD, Catanzarite ZB. Women’s wealth and intimate partner violence: insights from Ecuador and Ghana. Fem Econ. 2015;21(2):1–29. 13. Oduro AD, Deere CD, Catanzarite ZB. Women’s wealth and intimate partner violence: insights from Ecuador and Ghana. Fem Econ. 2015;21(2):1–29. References 1. Addressing violence against HIV positive women. http://www.endvawnow. org/en/articles/875-addressing-violence-against-hiv-positivewomen.html. Accessed 16th August, 2018. 1. Addressing violence against HIV positive women. http://www.endvawnow. org/en/articles/875-addressing-violence-against-hiv-positivewomen.html. Accessed 16th August, 2018. 2. Amoakohene MI. Violence against women in Ghana: a look at women’s perceptions and review of policy and social responses. Soc Sci Med. 2004; 59(11):2373–85. 2. Amoakohene MI. Violence against women in Ghana: a look at women’s perceptions and review of policy and social responses. Soc Sci Med. 2004; 59(11):2373–85. 3. Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ). Stigma and discrimination of people living with HIV in Ghana: a major challenge in the fight against AIDS. Accra: Deutsche Gesellschaft fürInternationale Zusammenarbeit (GIZ) Gmb; 2011. 3. Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ). Stigma and discrimination of people living with HIV in Ghana: a major challenge in the fight against AIDS. Accra: Deutsche Gesellschaft fürInternationale Zusammenarbeit (GIZ) Gmb; 2011. 4. Ebotabe, A., Johan, A Lacor, B, P and Deschepper, R (2015). “It’s my secret”: fear of disclosure among sub-Saharan African migrant women living with HIV/AIDS in Belgium, PLoS One, 10(3): 10–1371. 5. Gyimah A, Nakua EK, Owusu-Dabo E, Easmon Otupiri E. Contraceptive characteristics of women living with HIV in the Kumasi Metropolis, Ghana. Int J MCH AIDS. 2013;2(1):111–20. 6. Hatcher AM, Woollett N, Pallitto CC, Mokoatle K, Stockl H, MacPhail C, DelanyMoretlwe S, Garcia-Moreno C. Bidirectional links between HIV and intimate partner violence in pregnancy: implications for prevention of mother-to-child transmission. J Int AIDS Soc. 2014;17:19233. 6. Hatcher AM, Woollett N, Pallitto CC, Mokoatle K, Stockl H, MacPhail C, DelanyMoretlwe S, Garcia-Moreno C. Bidirectional links between HIV and intimate partner violence in pregnancy: implications for prevention of mother-to-child transmission. J Int AIDS Soc. 2014;17:19233. Authors’ information Authors information There is no information necessary to be written. 14. Sarnquist C, Kang J, Moyo P, Stranix-Chibanda L, Tagwira V, Chang D, Maldonado Y. Intimate partner violence and HIV-infection among women in Zimbabwe: a complex interplay. 142nd APHA annual meeting and exposition; 2014. Publisher’s Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Competing interests The authors declare that they have no competing interests. Ethics approval and consent to participate Not applicable Ethics approval and consent to participate Not applicable 18. UNAIDS. Report on the global AIDS epidemic, 2012. Geneva: UNAIDS; 2012. UNAIDS. Report on the global AIDS epidemic, 2012. Geneva: UNAID 18. UNAIDS. Report on the global AIDS epidemic, 2012. Geneva: UNAIDS; 2012. Availability of data and materials Since this manuscript is a protocol for a scoping review, there are no data to share. However, when the study is complete we would be happy to share the dataset. 16. Spangenberg K, Wobil P, Betts CL, Wiesner TF, Gold KJ. Intimate partner violence among mothers of sick newborns in Ghana. Health Care Women Int. 2015;11:1–12 6 UN Women (2012). 16. Spangenberg K, Wobil P, Betts CL, Wiesner TF, Gold KJ. Intimate partner violence among mothers of sick newborns in Ghana. Health Care Women Int. 2015;11:1–12 6 UN Women (2012). 17. UN-Women. (2012). Annual report 2011–2012. Retrieved from UN: http:// www.unwomen.org/en/digital-library/publications/2012/8/annual-report- 2011-2012 17. UN-Women. (2012). Annual report 2011–2012. Retrieved from UN: http:// www.unwomen.org/en/digital-library/publications/2012/8/annual-report- 2011-2012 Author details 1 Author details 1School of Nursing and Public Health, College of Health Sciences, University of KwaZulu-Natal, Desmond Clearance Building, Howard College Campus, Durban 4001, South Africa. 2Department of Nursing, Faculty of Allied Health Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. 3Department of Nursing, Faculty of Health Sciences, National Open University of Nigeria, Jabi, Abuja, Nigeria.
https://openalex.org/W2916628632
https://hal.archives-ouvertes.fr/hal-02065971/document
English
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Discrete Geometry from Quantum Walks
Condensed matter
2,019
cc-by
10,687
To cite this version: Fabrice Debbasch. Discrete Geometry from Quantum Walks. Condens.Mat., 2019, 4 (2), pp.40. ￿10.3390/condmat4020040￿. ￿hal-02065971￿ Distributed under a Creative Commons Attribution 4.0 International License Received: 28 February 2019; Accepted: 9 April 2019; Published: 11 April 2019 Abstract: A particular family of Discrete Time Quantum Walks (DTQWs) simulating fermion propagation in 2D curved space-time is revisited. Usual continuous covariant derivatives and spin-connections are generalized into discrete covariant derivatives along the lattice coordinates and discrete connections. The concepts of metrics and 2-beins are also extended to the discrete realm. Two slightly different Riemann curvatures are then defined on the space-time lattice as the curvatures of the discrete spin connection. These two curvatures are closely related and one of them tends at the continuous limit towards the usual, continuous Riemann curvature. A simple example is also worked out in full. Keywords: discrete time quantum walks; discrete geometry; discrete Riemann curvature; discrete metric Fabrice Debbasch Fabrice Debbasch Sorbonne Université, Observatoire de Paris, Université PSL, CNRS, LERMA, F-75005 Paris, France; fabrice.debbasch@gmail.com Sorbonne Université, Observatoire de Paris, Université PSL, CNRS, LERMA, F-75005 Paris, France; fabrice.debbasch@gmail.com   Condens. Matter 2019, 4, 40; doi:10.3390/condmat4020040 HAL Id: hal-02065971 https://hal.science/hal-02065971v1 Submitted on 1 Mar 2022 L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. Distributed under a Creative Commons Attribution 4.0 International License www.mdpi.com/journal/condensedmatter 1. Introduction Discrete Time Quantum Walks (DTQWs) are unitary quantum automata. They have been first considered by Feynman [1] as tools to discretise path integrals for fermions, and later introduced in a more formal and systematic way in Aharonov [2] and Meyer [3]. DTQWs have been realized experimentally with a wide range of physical objects and setups [4–10], and are studied in a large variety of contexts, ranging from quantum optics [10] to quantum algorithmics [11,12], condensed matter physics [13–17], hydrodynamics [18] and biophysics [19,20]. It has been shown recently [21–30] that several DTQWs admit as continuous limit the dynamics of Dirac fermions coupled to arbitrary Yang–Mills gauge fields (including electromagnetic fields) and to arbitrary relativistic gravitational fields. In addition, a DTQW coupled to a uniform electric field has already been realized experimentally [31]. Quite remarkably, the DTQWs which converge towards fermions coupled to Yang–Mills fields also admit exact discrete gauge invariances and discrete field strength ‘tensors’. These can be used e.g., to build new self-consistent discrete models of Dirac fermions interacting with Yang–Mills fields, where DTQWs are not only acted upon by gauge fields, but also act as sources to these fields. On the contrary, no exact discrete gauge invariance has been displayed for DTQWs which converge towards fermions coupled to gravitational fields, and no discrete field strength i.e., Riemann curvature has been defined either. This article demonstrates how this gap can be filled. We focus on a certain family of DTQWs in discrete 2D space-time whose continuous limit coincides the dynamics of a (massless) Dirac fermion. We first show that these admit an exact discrete Lorentz gauge invariance and then present two alternate definitions of the Riemann curvature for these walks. More precisely, we define for each discrete walk discrete covariant derivatives in the direction of the grid coordinates. These derivatives generalise the usual covariant derivatives of differential geometry and allow the identification, not only of a discrete metric and a discrete 2-bein, but also of a discrete spin-connection defined on the lattice. The basic idea is then to define the Riemann curvature tensor of the space-time lattice (or of the DTQW) Condens. Matter 2019, 4, 40; doi:10.3390/condmat4020040 www.mdpi.com/journal/condensedmatter www.mdpi.com/journal/condensedmatter 2 of 16 Condens. Matter 2019, 4, 40 as the curvature of the spin connection using as gauge group the set of Lorentz transformations acting on spinors [32,33]. 2. Results Blueprint: The 2D Dirac Equation 2.1. Blueprint: The 2D Dirac Equation 2.1. Blueprint: The 2D Dirac Equation The curved space-time Dirac equation is usually written in the form [34,35] iγaeµ a DµΨ = mΨ, (1) (1) where Ψ is a spinor, and eµ a are the n-bein coefficients, which we suppose to be symmetrical, i.e., eµ a = ea µ (note that this relation makes sense because there are as many values of µ as there are values of a and because it equates coefficients i.e., tensor components in a given basis, and not tensors). The γ’s are the so-called Dirac operators obeying the usual Clifford algebra, and where Ψ is a spinor, and eµ a are the n-bein coefficients, which we suppose to be symmetrical, i.e., eµ a = ea µ (note that this relation makes sense because there are as many values of µ as there are values of a and because it equates coefficients i.e., tensor components in a given basis, and not tensors). The γ’s are the so-called Dirac operators obeying the usual Clifford algebra, and Dµ = ∂µ + 1 8ωµab h γa, γbi . (2) (2) In 2D space-time, Greek and Latin indices above only take two values, conveniently denoted by 0 and 1. The spin-connection ω has thus only two independent components ω001 = −ω010 and ω101 = −ω110. The spinor Hilbert space is also two-dimensional and is equipped with the Hermitian product, < Ψ(x0, x1), Φ(x0, x1) >= Z x1∈R Ψ∗(x0, x1)Φ(x0, x1)µ(x0, x1)dx1, (3) (3) where µ = (−det(gµν))1/2 where gµν are the metric components built from the 2-bein, which can be defined by gµνeµ a eν b = ηab where (ηab) = diag(1, −1) are the components of the 2D Minkovski metric in an orthonormal basis of the tangent space. We now choose an orthonormal basis (b−, b+) in spinor space and represent an arbitrary spinor Ψ by its two components (Ψ−, Ψ+). We also choose the Dirac operators γ0 and γ1 to ensure that their matrix representations in this basis coincide respectively with σx and +iσy where y σx = 0 1 1 0 ! (4) and σy = 0 −i i 0 ! (5) σx = 0 1 1 0 ! (4) (4) and and σy = 0 −i i 0 ! (5) (5) are the first two Pauli matrices. 1. Introduction It turns out that there are actually two ways of implementing this idea and we therefore introduce two different discrete Riemann curvatures on the space-time lattice. The first Riemann curvature ρ∗depends on a (nearly arbitrary) reference connection while the second one ρs does not. It turns out that the curvature ρ∗of the DTQW essentially represents the difference between the curvature ρs of the DTQW and the curvature ρs of the reference connection. We also show that, in the continuous limit, the Riemann curvature tends towards the usual, continuous Riemann tensor. We finally compute the curvature ρs on a simple example before discussing all results. 2. Results The commutator then reads  γ0, γ1 = 2σz = −2diag(1, −1). Expanding the compact notation above, the Dirac therefore equation reads: (e0 0 −e0 1)  ∂0ψ−−ω001 2 ψ− + (e1 0 −e1 1)  ∂1ψ−−ω101 2 ψ− = −imψ+, (e0 0 + e0 1)  ∂0ψ+ + ω001 2 ψ+ + (e1 0 + e1 1)  ∂1ψ+ + ω101 2 ψ+ = −imψ−. (6) (6) The 2-bein, the metric and the two non-vanishing connection coefficients can then be practically read off directly from the Dirac equation. Taking the continuous limit of the QWs considered in this The 2-bein, the metric and the two non-vanishing connection coefficients can then be practically read off directly from the Dirac equation. Taking the continuous limit of the QWs considered in this Condens. Matter 2019, 4, 40 3 of 16 article delivers this form of the Dirac equation [22]. In the next section, we will use discrete derivatives and put the QW equations in a form similar to (6) and thus identify in the discrete equations a 2-bein, a metric and a connection. By definition, Lorentz transformations on spinors are generated by the commutator of the γ′s. Thus, in 2D space-time, the Lorentz transform Ψ(Λ) of a spinor Ψ has components Ψ±(Λ) = exp(±Λ)Ψ± for an arbitrary, possibly space- and time-dependent Λ. In addition, the components of the spin connection transform according to ωµab(Λ) = ωµab + ∂µΛ. It follows from this that Rµνab = ∂µωνab −∂νωµab is invariant under Lorentz transformation. This quantity is the (µνab)-, so-called mixed component of the Riemann curvature tensor. The components Rµναβ of the Riemann curvature tensor on the coordinate basis (∂µ) are Rµναβ = RµνabEa αEb β where (Ea α) are the coordinate basis components of the inverse 2-bein: eµ a Eb µ = δa b. The Ricci tensor and the scalar curvature are defined from Rµναβ in the standard manner. Note that the expression of Rµνab is linear in the connection because the Lorentz group is abelian in 2D space-time. In what follows, a discrete Riemann curvature tensor will be computed by implementing Lorentz transformations on the discrete equations and identifying an invariant quantity. 2.2. A Simple Two-Step Quantum Walk 2.2. A Simple Two-Step Quantum Walk We work with two-component wave-functions Ψ defined in 2D discrete space-time where instants are labeled by j ∈N and spatial positions are labeled by p ∈Z and Ψj = (ψj,p)p∈Z. We introduce a basis (bA) = (bL, bR) in Hilbert-space space and the components ΨA = (ΨL, ΨR) of the arbitrary wave-function Ψ in this basis. The Hilbert product is defined by < ψ, φ >= ∑A,j,p(ψA)∗ j,p(φA)j,p, which makes the basis (bA) orthonormal. Consider now the quantum walk Ψj+1 = UjTΨj where T is the spin-dependent spatial translation operator defined by (TΨj)j,p = (ψL j,p+1, ψR j,p−1)T and Uj is an SU(2) operator defined by (UjΨj)j,p = U(θj,p)ψj,p, (7) (UjΨj)j,p = U(θj,p)ψj,p, (7) U(θ) = −cos θ i sin θ −i sin θ + cos θ ! . (8) (7) where U(θ) = −cos θ i sin θ −i sin θ + cos θ ! . (8) (8) This article focuses on the two-step QW obtained by looking at the state of the original walk at only one in every two time steps, say the steps which correspond to even values of j (this is sometimes called the stroboscopic approach). This article focuses on the two-step QW obtained by looking at the state of the original walk at only one in every two time steps, say the steps which correspond to even values of j (this is sometimes called the stroboscopic approach). Written in full, the discrete equations of the two-step QW read: Written in full, the discrete equations of the two-step QW read: ψL j+2,p = cj+1,p  cj,p+1ψL j,p+2 −isj,p+1ψR j,p  + sj+1,p  sj,p−1φL j,p + icj,p−1ψR j,p−2  , ψR j+2,p = sj+1,p  icj,p+1ψL j,p+2 + sj,p+1ψR j,p  −cj+1,p  isj,p−1ψL j,p −cj,p−1ψR j,p−2  , (9) (9) where cj,p = cos θj,p and sj,p = sin θj,p As shown in [22], this two-step QW admits a continuous limit if θ admits one and this limit coincides with the Dirac equation in a curved 2D space-time where the spinor connection and curvature depend on the derivatives of θ. The aim of this article is to show that the discrete equation can also be used to define a discrete metric, a discrete space-time connection and a discrete Riemann ‘tensor’ i.e., a full discrete geometry. 2.3. Covariant Discrete Derivatives To define the geometry induced by this QW on the space-time lattice, it is necessary to change basis in the wave-function Hilbert space. The easiest way to do that is to write the equations of motion of the QW in an invariant, basis-independent manner by introducing covariant discrete derivatives in Hilbert space. p We start by defining the following simple, non covariant discrete derivatives: Condens. Matter 2019, 4, 40 4 of 16 Condens. Matter 2019, 4, 40 Condens. Matter 2019, 4, 40 4 of 16 4 of 16 (Dj f )jp = 1 2 ( fj+2,p −fj,p), (Dp f )j,p = 1 4 fj,p+2 −fj,p−2  , (10) (Dpp f )j,p = 1 4 fj,p+2 + fj,p−2 −2fj,p  , (10) where f is an arbitrary j- and p-dependent quantity. These are discrete versions of the usual partial derivatives. Inverting the above equations delivers: where f is an arbitrary j- and p-dependent quantity. These are discrete versions of the usual partial derivatives. Inverting the above equations delivers: fj+2,p = fj,p + 2(Dj f )jp, fj,p+2 = fj,p + 2(Dp f )j,p + 2(Dpp f )j,p, (11) fj,p−2 = fj,p −2(Dp f )j,p + 2(Dpp f )j,p. (11) The equation of motion of the QW can then be rewritten as: The equation of motion of the QW can then be rewritten as: (DjΨA)j,p = (Wj,pσ3)A B (DpΨB)j,p + (1/2)(Wj,p + Lj,p −1)A B ΨB j,p + (Wj,p)A B (DppΨB)j,p, (12) (12) where (WA B )j,p = cj+1,pcj,p+1 isj+1,pcj,p−1 isj+1,pcj,p+1 cj+1,pcj,p−1 ! , (13) (LA B )j,p = sj+1,psj,p+1 −icj+1,psj,p+1 −icj+1,psj,p−1 sj+1,psj,p+1 ! (14) (13) (14) and σ3 is the operator represented by the third Pauli matrix in the basis (bA) i.e., σ3 is represented by the matrix diag(1, −1) in the basis (bA). Suppose now we change spin basis and rewrite (12) in a new, possibly j- and p-dependent local basis bα = (b−, b+). We need to introduce the operator rj,p which transforms the original basis bA into the basis bα, (bα)j,p = (rj,p)A α bA, and its inverse r−1 j,p . Thus, ψjp = ψA jpbA = ψA jp (r−1)α A  jp bα = ψα jpbα so that ψα jp = (r−1)α A  jp ψA jp and ψA jp = (rA α )jpψα jp. jp jp jp jp jp jp Let us now define covariant time- and space-derivatives, starting with derivation with respect to time. 2.3. Covariant Discrete Derivatives One has: jp jp jp jp jp Let us now define covariant time- and space-derivatives, starting with derivation with respect to time. One has: (DjψA)j,p = 1 2  (rA α )j+2,pψα j+2,p −(rA α )j,pψα j,p  = (rA α )j,p + 2(DjrA α )j,p  (Djψα)j,p + (DjrA α )j,pψα j,p. (15) (15) This shows that (DjψA) does not transforms as ψA under a change of basis in Hilbert space, but this also suggests introducing a new, covariant time-derivative of the form This shows that (DjψA) does not transforms as ψA under a change of basis in Hilbert space, but this also suggests introducing a new, covariant time-derivative of the form  Dj(A)ψA j,p =  A1 j,p A B (DjψB)j,p +  A0 j,p A B ψB j,p , (16) (16) where (A) = (A0, A1) is an arbitrary j- and p-dependent field. Using (15), one can write:  Dj(A)ψA j,p = (rA α )j,p Dj(A)ψα j,p , (17) (17) where Dj(A)ψα j,p =  A1 j,p α β (Djψβ)j,p +  A0 j,p α β ψβ j,p, (18) with (A0)α β = (r−1)α A(A0)A B (rB β) + (r−1)α A(A1)A B (DjrB β) (19) where where Dj(A)ψα j,p =  A1 j,p α β (Djψβ)j,p +  A0 j,p α β ψβ j,p, (18) (18) β β with (A0)α β = (r−1)α A(A0)A B (rB β) + (r−1)α A(A1)A B (DjrB β) (19) with (A0)α β = (r−1)α A(A0)A B (rB β) + (r−1)α A(A1)A B (DjrB β) (19) (A0)α β = (r−1)α A(A0)A B (rB β) + (r−1)α A(A1)A B (DjrB β) (19) (19) ens. Matter 2019, 4, 40 5 of 16 Condens. Matter 2019, 4, 40 5 of 16 and (A1)α β = (r−1)α A(A1)A B (rB γ) ×  δγ β + 2(r−1)γ C(DjrC β )  , (20) (20) and the time- and space-indices j and p have been omitted from the latest equations for readability purposes. Equation (17) proves that Dj(A) is a covariant time-derivative. p p q ( ) p j( ) Space derivatives are slightly more complex. Using again (12), one can write: j Space derivatives are slightly more complex. 2.3. Covariant Discrete Derivatives Using again (12), one can write: (DpψA)j,p = 1 4  (rA α )j,p+2ψα j,p+2 −(rA α )j,p−2ψα j,p−2  = (rA α )j,p + 2(DpprA α )j,p  (Dpψα)j,p + (DprA α )j,p  ψα j,p + 2(Dppψα)j,p  (21) (21) and (DppψA)j,p = 1 4  (rA α )j,p+2ψα j,p+2 + (rA α )j,p−2ψα j,p−2 −2(rA α )j,pψα j,p  = (rA α )j,p + 2(DpprA α )j,p  (Dppψα)j,p + 2(DprA α )j,p(Dpψα)j,p + (DpprA α )j,pψα j,p. (22) (22) As before, this suggests defining a spatial covariant derivative by: As before, this suggests defining a spatial covariant derivative by:  Dp(A)ψA j,p =  A1 j,p A B (DpψB)j,p +  A0 j,p A B ψB j,p +  A2 j,p A B (DppψB)j,p (23) (23) where (A) = (A0, A1, A2) is an arbitrary j- and p-dependent field and the transformation laws for A reads (A0)α β = (r−1)α A(A0)A B (rB β) + (r−1)α A(A1)A B (DprB β) + (r−1)α A(A2)A B (DpprB β), (24) (A1)α β = (r−1)α A(A1)A B (rB γ) ×  δγ β + 2(r−1)γ C(DpprC β )  + 2(r−1)α A(A2)A B DprB β (25) (24) (25) and (A2)α β = (r−1)α A(A2)A B (rB γ) ×  δγ β + 2(r−1)γ C(DpprC β )  + 2(r−1)α A(A1)A B DprB β. (26) (A2)α β = (r−1)α A(A2)A B (rB γ) ×  δγ β + 2(r−1)γ C(DpprC β )  + 2(r−1)α A(A1)A B DprB β. (26) (26) The equation of motion (12) of the QW can be rewritten in terms of covariant derivatives. We introduce a time-connection A and a space-connection B, fixing only at this stage the values of their 1- and 2-components: The equation of motion (12) of the QW can be rewritten in terms of covariant derivatives. We introduce a time-connection A and a space-connection B, fixing only at this stage the values of their 1- and 2-components: (A1)A B = δA B , (27) (B1)A B = δA B , (B2)A B = (σ3)A B . 2.4.1. Preliminary Gauge Change Proceeding as in [22,23], we now change gauge i.e., spin basis by defining an operator r which puts Wj,pσ3 in diagonal form. The characteristic polynomial of Wj,pσ3 reads Proceeding as in [22,23], we now change gauge i.e., spin basis by defining an operator r which puts Wj,pσ3 in diagonal form. The characteristic polynomial of Wj,pσ3 reads (31) Pj,p(x) = x2 + cj,pδj,px −πj,p, (31) where δj,p = cj,p−1 −cj,p+1 and πj,p = cj,p−1cj,p+1. Let (xα)j,p, α = +, −be the two (possibly complex) roots of Pj,p. From Equations (12) and (30), the eigenvalues (xα)j,p actually determine two local transport velocities. More precisely, these eigenvalues actually define a set of local 2-bein coefficients (eµ 0, eν 1)jp (see above for details) on the space-time lattice. One finds e0 0 = 1, e0 1 = 0, e1 0 = (x+ + x−)/2, e1 1 = (x+ −x−)/2. This in turn defines the inverse metric ‘components’ on the space-time lattice g00 = 1, g11 = x+x−and g01 = (x+ + x−)/2. The determinant of these components is −µ2 = −(x+ −x−)2/4. In the usual differential, and thus continuous geometry, the Greek indices on n-bein coefficients, (inverse) metric components, etc. refer to components on the so-called coordinate basis (∂µ) = (∂t, ∂x). In the discrete case, the equivalent of the basis (∂µ) is clearly the set (Dj, Dp) and we therefore define accordingly the 2-bein ‘vectors’ e0 = ej 0Dj + ep 0Dp and e1 = ej 1Dj + ep 1Dp. The quantities gµν can be interpreted similarly as the components of the inverse metric gjjDj ⊗Dj + 2gjpDj ⊗Dp + gppDp ⊗Dp. Changes of space-time coordinates can then be implemented in the spirit of [36]. We finally define the discrete inverse 2-bein by the usual relations Ea µeµ b = δa b where δa b is the Kronecker symbol. µ We now recall that, in curved space-time, a spinor is normalized to unity, not with respect to the usual Lebesgue measure d2x , but with respect to the metric-induced measure p (−detg)d2x where detg stands for the determinant of the metric components. This means that the usual Hilbert product < ψ, φ >= ∑A,j,p(ψA)∗ j,p(φA)j,p, which makes the initial basis bA orthonormal, does not coincide with the natural Hilbertian product to be used in spinor space. 2.4.1. Preliminary Gauge Change We therefore define the new Hilbertian product by < ψ, φ >s= ∑A,j,p µj,p(ψA)∗ j,p(φA)j,p, a new basis (bα)j,p made of two eigenvectors of Wσ3 normalized with respect to < · >s and we define rj,p as the operator which transforms the original basis bA into the basis bα. 2.4.2. Choice of the Mass and Space-Time-Connection 2.3. Covariant Discrete Derivatives (28) (27) (28) We also introduce a ‘mass’M and impose that We also introduce a ‘mass’M and impose that We also introduce a ‘mass’M and impose that −iMA B + (Wσ3B0)A B −(A0)A B = (1/2)(W + L −1)A B , (29) (29) thus ensuring that the equation of motion (12) can be written as: thus ensuring that the equation of motion (12) can be written as: thus ensuring that the equation of motion (12) can be written as: thus ensuring that the equation of motion (12) can be written as: Dj(A)ψA = (Wσ3)A B Dp(B)ψB −iMA B ψB. (30) (30) The 0-components of both connections and of the mass M will be specified in the next section. In addition, the status of M is discussed in the last section of this article. The 0-components of both connections and of the mass M will be specified in the next section. In addition, the status of M is discussed in the last section of this article. Equation (30) is one step closer to the continuous Dirac equation that the original form of the equations of motion obeyed by the two-step walk. In particular, it shows that the time-connection A Condens. Matter 2019, 4, 40 6 of 16 and the space-connection B are to be understood as two components of a single, space-time connection (A, B). This point of view will be adopted form here on. and the space-connection B are to be understood as two components of a single, space-time connection (A, B). This point of view will be adopted form here on. The most important difference between (30) and (6) is that the operator Wσ3 is not diagonal in the basis (bA). Changing spin basis to make this operator diagonal is the goal of the next section. and Space-Time Connection iminary Gauge Change 2.4. Mass and Space-Time Connection 2.4.2. Choice of the Mass and Space-Time-Connection Let us now specify the 0-components of the connections A and B as well as the mass M. Equations (29), (27) and (28) lead to: −iMα β + (Wσ3B0)α β − (A0)α β = N α β , (32) (32) where N α β = (1/2)(W + L −1)α β −(r−1)α A(A1)A B DjrB β + (Wσ3)α γ(r−1)γ A  (B1)A B DprB β + (B2)A B DpprB β  = (1/2)(W + L −1)α β −(r−1)α ADjrA β + (Wσ3)α γ(r−1)γ A  δA B DprB β + (σ3)A B DpprB β  . (33) (33) We now define −iMα β as the non-diagonal part of N α β . This fully specifies M in any basis of the Hilbert space and it also leads to We now define −iMα β as the non-diagonal part of N α β . This fully specifies M in any basis of the Hilbert space and it also leads to (Wσ3B0)α β − (A0)α β = Oα β, (34) (34) 7 of 16 Condens. Matter 2019, 4, 40 where Oα β is the diagonal part of N α β . Since r was chosen to make (Wσ3)α β diagonal, this last equation makes it possible to choose both (A0)α β and (B0)α β diagonal, and (34) becomes a system of two equations for the four unknown (A0)− −, (A0)+ +, (B0)− −, (B0)+ +. In a generic situation, this system can be solved in a unique manner by imposing a couple of extra constraints on the unknown. We choose the same constraints as in the continuous case (see Section 2.1) i.e., (A0)− −= −(A0)+ + and (B0)− −= −(B0)+ +, which make both (A0)α β and (B0)α β proportional to the third Pauli matrix σz. 2.5. Local Lorentz Transformations Extending the definition of global Lorentz transformations for DTQWs proposed in [36], we now define the local Lorentz transform of the spinor Ψ by ψ− j,p →λj,pψ− j,p and ψ+ j,p →λ−1 j,p ψ+ j,p for an arbitrary, real and non-vanishing field λ defined on the 2D space-time lattice. Alternately, upon a Lorentz transformation, ψ →exp(Λσz)ψ where λ = exp(Λ) and σz is the operator represented by the third Pauli matrix in the basis (b−, b+), and we use the practical notation ψα(Λ) = ρα β(Λ)ψβ where ρα β(Λ) = exp(Λσz). Evidently, (ρ−1)α β(Λ) = exp(−Λσz). ρβ p y ρ β p Let us now compute the Lorentz transform of the DTQW equation of motion. β β Let us now compute the Lorentz transform of the DTQW equation of motion. The mass M is anti-diagonal, so we write The mass M is anti-diagonal, so we write The mass M is anti-diagonal, so we write M = 0 M− + M+ − 0 ! , (35) (35) which is not invariant under Lorentz transformation but becomes which is not invariant under Lorentz transformation but becomes M(Λ) = 0 e−2ΛM− + e+2ΛM+ − 0 ! . (36) (36) Note that the product M− +M+ −, which can be interpreted as the squared mass of the walk, is invariant under Lorentz transformation. Note that the product M− +M+ −, which can be interpreted as the squared mass of the walk, is invariant under Lorentz transformation. The connection matrices also change under Lorentz transformation. Of particular interest are the diagonal parts of these connections because they obey a relatively simple transformation law. 2.5. Local Lorentz Transformations Indeed, (A0)− −(Λ) = (A0)− −+ (A1)− −× 1 2 exp(2DjΛ) −1  , (37) (A0)+ +(Λ) = (A0)+ + + (A1)+ + × 1 2 exp(−2DjΛ) −1  , (38) (A0)− −(Λ) = (A0)− −+ (A1)− −× 1 2 exp(2DjΛ) −1  , (37) (A0)+ +(Λ) = (A0)+ + + (A1)+ + × 1 2 exp(−2DjΛ) −1  , (38) (B0)− −(Λ) = (B0)− −+ 1 2 (B1)− −exp(2DppΛ) sinh(2DpΛ) 2 1  (39) (37) (A0)+ +(Λ) = (A0)+ + + (A1)+ + × 1 2 exp(−2DjΛ) −1  , (38) (38) (B0)− −(Λ) = (B0)− −+ 1 2 (B1)− −exp(2DppΛ) sinh(2DpΛ) + (B2)− −× 1 2 exp(2DppΛ) cosh(2DpΛ) −1  , (39) (39) (B0)+ +(Λ) = (B0)+ + + 1 2 (B1)+ + exp(−2DppΛ) sinh(−2DpΛ) + (B2)+ + × 1 2 exp(−2DppΛ) cosh(−2DpΛ) −1  , (40) (B1)− −(Λ) = (B1)− −exp(2DppΛ) cosh(2DpΛ) + (B2)− −exp(2DppΛ) sinh(2DpΛ), (41) (B0)+ +(Λ) = (B0)+ + + 1 2 (B1)+ + exp(−2DppΛ) sinh(−2DpΛ) + (B2)+ + × 1 2 exp(−2DppΛ) cosh(−2DpΛ) −1  , (40) (B1)−(Λ) (B1)−exp(2D Λ) cosh(2D Λ) (40) (B1)− −(Λ) = (B1)− −exp(2DppΛ) cosh(2DpΛ) + (B2)− −exp(2DppΛ) sinh(2DpΛ), (41) (41) (B1)+ +(Λ) = (B1)+ + exp(−2DppΛ) cosh(−2DpΛ) + (B2)+ + exp(−2DppΛ) sinh(−2DpΛ). (42) (42) The first two equations lead to The first two equations lead to ∆A0(Λ) = (A1)− −(A1)+ + sinh(2DjΛ), (43) ∆A0(Λ) = (A1)− −(A1)+ + sinh(2DjΛ), (43) (43) Matter 2019, 4, 40 8 of 16 Condens. Matter 2019, 4, 40 8 of 16 where ∆A0(Λ) = (A1)+ +  (A0)− −(Λ) −(A0)− −  −(A1)− −  (A0)+ +(Λ) −(A0)+ +  . (44) ∆A0(Λ) = (A1)+ +  (A0)− −(Λ) −(A0)− −  −(A1)− −  (A0)+ +(Λ) −(A0)+ +  . (44) (44) The following two equations lead to The following two equations lead to The following two equations lead to exp(+2DppΛ) = 2 (B0)− −(Λ) −(B0)− −+ (B2)− −/2 (B1)− −sinh(2DpΛ) + (B2)− −cosh(2DpΛ), exp(−2DppΛ) = 2 (B1)+ +(Λ) −(B0)+ + + (B2)+ +/2 −(B1)+ + sinh(2DpΛ) + (B2)+ + cosh(2DpΛ), (45) (45) while the final two equations deliver while the final two equations deliver exp(+2DppΛ) = (B1)− −(Λ) (B1)− −cosh(2DpΛ) + (B2)− −sinh(2DpΛ), exp(−2DppΛ) = (B1)+ +(Λ) (B1)+ + cosh(2DpΛ) −(B2)+ + sinh(2DpΛ). 2.5. Local Lorentz Transformations (46) (46) Equating both expressions of exp(±2DppΛ) delivers Equating both expressions of exp(±2DppΛ) delivers tanh(+2DpΛ) = S− −(B(λ), B) C− −(B(λ), B) = T − −(B(λ), B), tanh(−2DpΛ) = S+ +(B(λ), B) C+ +(B(λ), B) = T + + (B(λ), B), (47) (47) where S− −(B(λ), B) = −(B1)− −  (B0)− −(Λ) −(B0)− −+ (B2)− −/2  + (B2)− −(B1)− −(Λ)/2, (48) C− −(B(λ), B) = +(B2)− −  (B0)− −(Λ) −(B0)− −+ (B2)− −/2  −(B1)− −(B1)− −(Λ)/2, (49) S+ +(B(λ), B) = +(B1)+ +  (B0)+ +(Λ) −(B0)+ + + (B2)+ +/2  −(B2)+ +(B1)+ +(Λ)/2, (50) C+ +(B(λ), B) = +(B2)+ +  (B0)+ +(Λ) −(B0)+ + + (B2)+ +/2  −(B1)+ +(B1)− −(Λ)/2. (51) (48) (49) (51) It is best to retain for tanh(+2DpΛ) an expression which does not favour a set of components over the other. We therefore choose It is best to retain for tanh(+2DpΛ) an expression which does not favour a set of components over the other. We therefore choose tanh(+2DpΛ) = 1 2 T − −(B(Λ), B) −T + + (B(Λ), B)  (52) (52) as the final expression for tanh(+2DpΛ). as the final expression for tanh(+2DpΛ). 2.6. Riemann Curvature I Assuming that (A1)− −(A1)+ + does not vanish and inverting the functions sinh and tanh, Equations (43) and (52) can be rewritten under the form DjΛ = Lj(A(Λ), A), DpΛ = Lp(B(Λ), B). (53) (53) The identity [Dj, Dp] = 0 then leads to DpLj(A(Λ), A) −DjLp(B(Λ), B) = 0. (54) DpLj(A(Λ), A) −DjLp(B(Λ), B) = 0. (54) Condens. Matter 2019, 4, 40 9 of 16 Introduce now a reference connection (A∗, B∗), with the sole constraint that Lj(A∗, A) and Lp(B∗, B) are both defined, and write Lj(A(Λ), A) = Lj(A∗, A) + L∗ j (A(Λ), A), Lp(B(Λ), B) = Lp(B∗, B) + L∗ p(B(Λ), B). (55) (55) Note that the identities Lj(A, A) = Lp(B, B) = 0 then imply Note that the identities Lj(A, A) = Lp(B, B) = 0 then imply Note that the identities Lj(A, A) = Lp(B, B) = 0 then imply L∗ j (A, A) = −Lj(A∗, A), L∗ p(B, B) = −Lp(B∗, B). (56) (56) We then define the discrete Riemann curvature ρ∗ jp(Λ) by ρ∗ jp(Λ) = +  DpL∗ j (A(Λ), A)  j,p −  DjL∗ p(B(Λ), B)  j,p . 2.5. Local Lorentz Transformations (57) (57) By (56), ρ∗ jp(0) = − DpLj(A∗, A)  j,p + DjLp(B∗, B)  j,p , (58) (58) which represents the discrete Riemann curvature ρ∗of the connection (A, B) i.e., the curvature ρ∗of the DTQW. which represents the discrete Riemann curvature ρ∗of the connection (A, B) i.e., the curvature ρ∗of the DTQW. 2.7. Riemann Curvature II 2.7. Riemann Curvature II Matter 2019, 4, 40 one then needs only one of the two variations and it is natural to retain ¯B0(Λ). The equation for DpΛ then reads 0 0 ! n needs only one of the two variations and it is natural to retain ¯B0(Λ). The equation for DpΛ ads one then needs only one of the two variations and it is natural to retain ¯B0(Λ). The equation for DpΛ th d DpΛ ≈1 2 ( ¯B0)− −(Λ) (B1)− − −( ¯B0)+ +(Λ) (B1)+ + ! (63) (63) and the equation for DjΛ becomes similarly DjΛ ≈1 2 ( ¯A0)− −(Λ) (A1)− − −( ¯A0)+ +(Λ) (A1)+ + ! , (64) (64) where ¯A(Λ) = A(Λ) −A. where ¯A(Λ) = A(Λ) −A. where ¯A(Λ) = A(Λ) −A. where A(Λ) = A(Λ) −A. From this choice and the identity [Dj, Dp] = 0 follows ( ) ( ) From this choice and the identity [Dj, Dp] = 0 follows ( ) ( ) From this choice and the identity [Dj, Dp] = 0 follows From this choice and the identity [Dj, Dp] = 0 follows 0 = 1 2 Dj ( ¯B0)− −(Λ) (B1)− − −( ¯B0)+ +(Λ) (B1)+ + ! − 1 2 Dp ( ¯A0)− −(Λ) (A1)− − −( ¯A0)+ +(Λ) (A1)+ + ! , (65) (65) where the s index stands for ‘slow’. The ‘slow’ discrete Riemann curvature tensor ρs jp(Λ) of a connection is then defined by: ρs jp(Λ) = 1 2 Dj (B0(Λ))− − (B1)− − −(B0(Λ))+ + (B1)+ + ! −1 2 Dp (A0(Λ))− − (A1)− − −(A0(Λ))+ + (A1)+ + ! , (66) (66) where the index ‘s’ stands for slow, ensuring that ρs jp(Λ) = ρs jp(0). In addition, the Riemann of the DTQW is defined as ρs jp(0). 2.7. Riemann Curvature II Suppose now that one is interested in a curvature which caracterizes only how the connection coefficients change under Lorentz transformations which vary slowly in time and space i.e., for which DjΛ, DpΛ and DppΛ are all much smaller than unity. At the continuous limit, all Lorentz transformations are automatically slowly varying in both time and space because the time and space coordinates t and x are related to j and p by tj = ϵj and xp = ϵp, where ϵ is an infinitesimal [22,23], so that Dp ∼ϵ∂x and Dpp ∼ϵ2∂xx. However, slowly varying Lorentz transformations can also be considered outside the continuous limit (see the example in the next section). The limit case of Lorentz transformations varying slowly in space is actually singular. Indeed, in the general case, Equations (37)–(42) relate the two independent variations B0(Λ) −B0 and B1(Λ) −B1 to the two independent discrete derivatives DpΛ and DppΛ. Inverting these equations thus delivers DpΛ in terms of the two independent variables B0(Λ) −B0 and B1(Λ) −B1. To study the limit case of slowly varying Lorentz transformations, suppose DpΛ = O(ϵ) and DppΛ = O(ϵα) with α > 1. Equations (37)–(42) then read: (B0)− −(Λ) = (B0)− −+ (B1)− −DpΛ + o(ϵ), (59) (59) (B0)+ +(Λ) = (B0)+ + −(B1)+ +DpΛ + o(ϵ), (60) (B0)+ +(Λ) = (B0)+ + −(B1)+ +DpΛ + o(ϵ), (60) (60) (B1)− −(Λ) = (B1)− −+ 2(B2)− −DpΛ + o(ϵ), (61) (B1)− −(Λ) = (B1)− −+ 2(B2)− −DpΛ + o(ϵ), (61) (B1)+ +(Λ) = (B1)+ + −2(B2)+ +DpΛ + o(ϵ). (62) (62) At the first order in ϵ, DppΛ vanishes from the equations so both variations ¯B0(Λ) = B0(Λ) −B0 and ¯B1(Λ) = B1(Λ) −B1 depend on the single variable DpΛ and they are therefore not independent. Indeed, ¯B1(Λ) = 2B2 ¯B0(Λ). In this limit, the general problem, which depends on two variables, thus degenerates into a single variable problem, thus making the limit singular. To define curvature, At the first order in ϵ, DppΛ vanishes from the equations so both variations ¯B0(Λ) = B0(Λ) −B0 and ¯B1(Λ) = B1(Λ) −B1 depend on the single variable DpΛ and they are therefore not independent. Indeed, ¯B1(Λ) = 2B2 ¯B0(Λ). In this limit, the general problem, which depends on two variables, thus degenerates into a single variable problem, thus making the limit singular. To define curvature, 10 of 16 Condens. Matter 2019, 4, 40 Condens. 2.8. Relation between the Two Riemann Curvatures Let us now investigate how this second discrete Riemann tensor is related to the first one introduced in the previous section. To do so, suppose that both connections (A∗, B∗) and (A(Λ), B(Λ)) are close to (A, B), in the sense that their coefficients in the basis (bα) are close to those of (A, B). This implies in particular that DjΛ, DpΛ and DppΛ are small (see Equations (37)–(42)) i.e., that Λ is slowly varying in time and space. To simplify the discussion, we also suppose that there exist a Λ∗ such that (A∗, B∗) = (A(Λ∗), B(Λ∗)), and Λ∗is then also slowly varying in time and space. We now convert Lj and Lp into a function ¯Lj of ( ¯A(Λ), A) and a function ¯Lp of ( ¯B(Λ), B) and expand these two newly introduced functions in their first variable at first order around 0. This leads to: ¯Lj( ¯A(Λ), A) ≈ ¯A(Λ) ∂¯Lj ∂¯A ! (0,A) , ¯Lj( ¯A(Λ∗), A) ≈ ¯A(Λ∗) ∂¯Lj ∂¯A ! (0,A) , ¯Lp( ¯B(Λ), B) ≈ ¯B(Λ) ∂¯Lp ∂¯B  (0,B) , ¯Lp( ¯B(Λ∗), B) ≈ ¯B(Λ∗) ∂¯Lp ∂¯B  (0,B) . (67) (67) 11 of 16 Condens. Matter 2019, 4, 40 From this follows that From this follows that ¯L∗ j ( ¯A(Λ), A) ≈ (A(Λ) −A(Λ∗)) ∂¯Lj ∂¯A ! (0,A) , ¯L∗ p( ¯B(Λ), B) ≈ (B(Λ) −B(Λ∗)) ∂¯Lp ∂¯B  (0,B) , (68) (68) which leads to which leads to which leads to ρ∗ jp(Λ) ≈¯ρjp(Λ) −¯ρjp(Λ∗), (69) ρ∗ jp(Λ) ≈¯ρjp(Λ) −¯ρjp(Λ∗), (69) where ¯ρjp(Λ) = Dp  ¯A(Λ) ∂¯Lj ∂¯A ! (0,A)  −Dj ¯B(Λ) ∂¯Lp ∂¯B  (0,B) ! . (70) (70) Using again (67), this becomes ¯ρjp(Λ) = Dp ¯Lj( ¯A(Λ), A)  −Dj ¯Lp( ¯B(Λ), B)  . (71) (71) Now, by definition, ¯Lj represents DjΛ and ¯Lp represents DpΛ. Since we are considering Λ’s which vary slowly in time and space, Equations (63) and (64) are valid. Thus, ρ∗ jp(Λ) ≈ρs jp(Λ) −ρs jp(Λ∗). (72) (72) In particular, ρ∗ jp(0) = ρs jp(0) −ρs jp(Λ∗), which links the two Riemann curvatures ρ∗and ρs of the space-time lattice. In particular, ρ∗ jp(0) = ρs jp(0) −ρs jp(Λ∗), which links the two Riemann curvatures ρ∗and ρs of the space-time lattice. 2.9. Continuous Limit The discrete Riemann curvature then tends towards ϵ2/2 × Rµνab, where Rµνab is the mixed component of the usual Riemann curvature tensor to µ = 0, ν = 1, a = 0, b = 1. This component contains all the information one needs about the Riemann tensor because this tensor, in 2D space-times, has only one independent component. The 1/2 in the multiplicative factor comes form the fact that the zeroth components of the discrete connection tend towards ω/2 (as opposed to ω). The ϵ2 factor comes from the fact that curvatures are obtained by taking second discrete or continuous derivatives and that the above relation between (j, p) and (t, x) implies Dj = ϵ∂t and Dp = ϵ∂x. Finally, the components Rµν01 of the continuous Riemann curvature tensor on the coordinate basis (∂µ) can be recovered by taking the continuous limit of Ea µEb νρs where (Ea µ) is the discrete inverse 2-bein. 2.9. Continuous Limit Let us now discuss the continuous limit of ρs. The continuous limit addresses situations where the operator U and the wave-function of the walk vary on time- and space-scale much larger than the grid cell. The physical time t and spatial coordinate x along the grid are related to j and p by tj = ϵj and xp = ϵp where ϵ is an infinitesimal. It has been shown in [22,23] that the continuous limit of the 2-step walk then coincides with the Dirac equation in a curved space-time with metric (gµν) = diag(1, cos−2 θ). In particular, the matrices representing A1 and B1 in the basis (bα) then tend towards unity while the matrix representing A0 tends towards −(ω001/2) × 1 and B0 tends towards −(ω101/2) × 1. The discrete Riemann curvature then tends towards ϵ2/2 × Rµνab, where Rµνab is the mixed component of the usual Riemann curvature tensor to µ = 0, ν = 1, a = 0, b = 1. This component contains all the information one needs about the Riemann tensor because this tensor, in 2D space-times, has only one independent component. The 1/2 in the multiplicative factor comes form the fact that the zeroth components of the discrete connection tend towards ω/2 (as opposed to ω). The ϵ2 factor comes from the fact that curvatures are obtained by taking second discrete or continuous derivatives and that the above relation between (j, p) and (t, x) implies Dj = ϵ∂t and Dp = ϵ∂x. Finally, the components Rµν01 of the continuous Riemann curvature tensor on the coordinate basis (∂µ) can be recovered by taking the continuous limit of Ea µEb νρs where (Ea µ) is the discrete inverse 2-bein. Let us now discuss the continuous limit of ρs. The continuous limit addresses situations where the operator U and the wave-function of the walk vary on time- and space-scale much larger than the grid cell. The physical time t and spatial coordinate x along the grid are related to j and p by tj = ϵj and xp = ϵp where ϵ is an infinitesimal. It has been shown in [22,23] that the continuous limit of the 2-step walk then coincides with the Dirac equation in a curved space-time with metric (gµν) = diag(1, cos−2 θ). 2.9. Continuous Limit In particular, the matrices representing A1 and B1 in the basis (bα) then tend towards unity while the matrix representing A0 tends towards −(ω001/2) × 1 and B0 tends towards −(ω101/2) × 1. The discrete Riemann curvature then tends towards ϵ2/2 × Rµνab, where Rµνab is the mixed component of the usual Riemann curvature tensor to µ = 0, ν = 1, a = 0, b = 1. This component contains all the information one needs about the Riemann tensor because this tensor, in 2D space-times, has only one independent component. The 1/2 in the multiplicative factor comes form the fact that the Let us now discuss the continuous limit of ρs. The continuous limit addresses situations where the operator U and the wave-function of the walk vary on time- and space-scale much larger than the grid cell. The physical time t and spatial coordinate x along the grid are related to j and p by tj = ϵj and xp = ϵp where ϵ is an infinitesimal. It has been shown in [22,23] that the continuous limit of the 2-step walk then coincides with the Dirac equation in a curved space-time with metric (gµν) = diag(1, cos−2 θ). In particular, the matrices representing A1 and B1 in the basis (bα) then tend towards unity while the matrix representing A0 tends towards −(ω001/2) × 1 and B0 tends towards y p g ( ) −(ω101/2) × 1. The discrete Riemann curvature then tends towards ϵ2/2 × Rµνab, where Rµνab is the mixed component of the usual Riemann curvature tensor to µ = 0, ν = 1, a = 0, b = 1. This component contains all the information one needs about the Riemann tensor because this tensor, in 2D space-times, has only one independent component. The 1/2 in the multiplicative factor comes form the fact that the zeroth components of the discrete connection tend towards ω/2 (as opposed to ω). The ϵ2 factor comes from the fact that curvatures are obtained by taking second discrete or continuous derivatives and that the above relation between (j, p) and (t, x) implies Dj = ϵ∂t and Dp = ϵ∂x. Finally, the components Rµν01 of the continuous Riemann curvature tensor on the coordinate basis (∂µ) can be recovered by taking the continuous limit of Ea µEb νρs where (Ea µ) is the discrete inverse 2-bein. −(ω101/2) × 1. 2.10. Example The continuous limit of the walks studied in this article corresponds to the propagation of a Dirac spinor in a space-time metric of the form ds2 = dt2 −a2(t, x)dx2 where t and x are the continuous coordinates corresponding to j and p and a(t) = 1/(cos θ). Fixing these coordinates i.e., retaining this form for the metric, the simplest space-times with non vanishing curvature are realized by choosing the function a independent of x. We now therefore choose an angle θ which depends only on j and Condens. Matter 2019, 4, 40 12 Condens. Matter 2019, 4, 40 12 of 16 proceed to compute, as an example, the first of the curvatures defined above. Since nothing depends on the spatial position, all quantities are now indexed by j only. proceed to compute, as an example, the first of the curvatures defined above. Since nothing depends on the spatial position, all quantities are now indexed by j only. p p q y j y For such walks, the operators W and L take the simpler form For such walks, the operators W and L take the simpler form (WA B )j = cj cj+1 isj+1 isj+1 cj+1 ! , (73) (WA B )j = cj cj+1 isj+1 isj+1 cj+1 ! , (73) (LA B )j = sj sj+1 −icj+1 −icj+1 sj+1 ! (74) (WA B )j = cj cj+1 isj+1 isj+1 cj+1 ! , (73) (LA B )j = sj sj+1 −icj+1 −icj+1 sj+1 ! (74) (73) (LA B )j = sj sj+1 −icj+1 −icj+1 sj+1 ! (74) (74) and ((W + L)A B )j = cos(∆θj) i sin(∆θj) i sin(∆θj) cos(∆θj) ! (75) and ((W + L)A B )j = cos(∆θj) i sin(∆θj) i sin(∆θj) cos(∆θj) ! (75) (75) with ∆θj = θj+1 −θj. with ∆θj = θj+1 −θj. jj j j+ j A simple computation leads to (x±)j = ± | cj |. These values of (x±)j lead to (gjj)j = 1, (gpp)j = −c2 j and (gjp)j = 0. If θj ̸= π/2, the components of the discrete metric itself read (gjj)j = 1, (gpp)j = −c−2 j and (gjp)j = 0. In addition, −µ2 = −c2 j . We now retain (assuming cj ̸= 0) A simple computation leads to (x±)j = ± | cj |. These values of (x±)j lead to (gjj)j = 1, (gpp)j = −c2 j and (gjp)j = 0. 3. Conclusions We have revisited a particular family of DTQWs whose continuous limit coincides with the 2D curved space-time Dirac dynamics written in synchronous coordinates. We have defined discrete covariant derivatives of the spinor wave-function along the grid coordinates, thus introducing discrete spin-connections and also generalised the notions of metric and 2-bein to the discrete lattice. We have then defined two different discrete curvatures from the transformation properties of the discrete spin-connections under Lorentz transformations. Both curvatures are closely related and one of them coincides, in the continuous limit, with the usual Riemann curvature from differential geometry. We have finally computed this discrete Riemann curvature on a particularly simple example. Let us now comment on these results. In an arbitrary space-time, the most complete characterization of curvature is given the Riemann tensor. This tensor is usually computed from the space-time connection, but it can also be obtained from spinor connection [32,33]. The definition and computation of discrete curvature presented in this article thus start with a definition of discrete spinor connections for DTQWs, which is itself based upon the definition of discrete first and second discrete partial derivatives with respect to the grid coordinates. In the discrete case, spinor connections have a richer structure than in the continuous case because they contain more coefficients. In 2D space-time, a continuous spinor connection is fully defined by two coefficients, whereas one needs five coefficients to fully define a discrete spinor connection. These five coefficients can be partitioned into two sets, one of two coefficients pertaining to discrete covariant derivatives with respect to the discrete time index j, and one of three coefficients pertaining to covariant derivatives with respect to the discrete space index p. Note that these two sets only mix if one performs discrete Lorentz transformations in space-time, and these have not been considered in this article, where only Lorentz transformations in spinor space are carried out. We have therefore chosen, for readability purposes, to use a different letter for each set of coefficients (A defines discrete covariant time-derivatives and B defines discrete covariant space-derivatives). In addition, the discrete space-time connection is thus represented by (A, B). 2.10. Example If θj ̸= π/2, the components of the discrete metric itself read (gjj)j = 1, (gpp)j = −c−2 j and (gjp)j = 0. In addition, −µ2 = −c2 j . We now retain (assuming cj ̸= 0) A simple computation leads to (x±)j = ± | cj |. These values of (x±)j lead to (gjj)j = 1, (gpp)j = −c2 j and (gjp)j = 0. If θj ̸= π/2, the components of the discrete metric itself read (gjj)j = 1, (gpp)j = −c−2 j and (gjp)j = 0. In addition, −µ2 = −c2 j . We now retain (assuming cj ̸= 0) (b−)j = | cj |−1/2 iσjbL + κjbR  , (b+)j = | cj |−1/2 κjbL + iσjbR  , (76) (76) where κj = cos(θj+1/2) and σj = sin(θj+1/2). The matrix (rA α )j can be read off these equations (rA α )j =| cj |−1/2 iσj κj κj iσj ! (77) (77) and its inverse reads: ((r−1)α A)j =| cj |+1/2 −iσj κj κj −iσj ! . (78) ((r−1)α A)j =| cj |+1/2 −iσj κj κj −iσj ! . (78) (78) The components of W + L are not modified by the change of basis i.e., ((W + L)α β)j = cos(∆θj) i sin(∆θj) i sin(∆θj) cos(∆θj) ! (79) (79) and a direct computation delivers and a direct computation delivers and a direct computation delivers (Mα β) = 0 ¯ M ¯ M 0 ! (80) (Mα β) = 0 ¯ M ¯ M 0 ! (80) i h (80) with with with ¯ M = −1 2 sin(∆θ)+ | c |+1/2  κDj(| c |−1/2 σ) −σDj(| c |−1/2 κ)  , (81) (81) where the index j tracing the time-dependence of all quantities has been suppressed for readability purposes. y p p Since all angles depend only on j, only the connection B enters the curvature. One finds that Since all angles depend only on j, only the connection B enters the curvature. One finds that ((B1)α β) = 1, (82) (82) (B0)− −= −| c |−1/2  κDj(| c |−1/2 κ) + σDj(| c |−1/2 σ)  + 1 2 | c |(cos ∆θ −1), (83) (83) 13 of 16 Condens. Matter 2019, 4, 40 while (B0)+ + = −(B0)− −and ((B2)α β)j = −cos(θj+1) −i sin(θj+1) i sin(θj+1) cos(θj+1) ! . 2.10. Example (84) (84) This leads to ρs j = Dj(B0)− −with (B0)− −given by Equation (83). 3. Conclusions It therefore defines a Laplace operator on the discrete structure where it lives and, thus, a Ricci curvature. Similarly, a DTQW is essentially a spin 1/2 wave propagating on the lattice. Since a spin 1/2 wave obeys the Dirac equation, a DTQW essentially defines discrete equivalents to all quantities appearing in the Dirac equation i.e., an n-bein, and thus a metric, and a spin-connection. Once one has a discrete equivalent of the spin-connection, one can compute its curvature (in the sense of gauge theories), which coincides with the Riemann curvature. It is remarkable that classical Markov chains thus provide only a generalization of the Ricci curvature while quantum walks deliver equivalents to all geometrical objects of usual interest, from the metric to the spin-connection and, thus to the full Riemann curvature tensor. As already mentioned, curvature is often introduced in differential geometry without using spinors. A standard approach is to first define a notion of parallel transport for tensor (including vector and 1-form) fields and then introduce curvature as the natural object which measures how much parallel transport along an infinitesimal closed loop modifies a tensor field. The parallel transport generates a covariant derivative of tensor fields and, thus, a space-time connection, encoded for example in the Christoffel symbols, which can be used to compute the space-time curvature. However, the space-time connection can also be represented by the so-called rotation coefficients, which determine the covariant derivatives of the n-bein. Now, this space-time connection can be extended in a canonical way to spinor fields. One can thus define the covariant derivatives of spinor fields and these can be used to compute directly the space-time curvature. This approach presents the advantage of being very close in spirit to Yang–Mills gauge theories: at each point in space-time the fiber is the spinor Hilbert space, the theory is invariant under the local action of various gauge groups (U(1), the Lorentz group, etc.) in this fiber, and one computes for each group the curvature or field strength from the associated covariant spinor derivative. Let us add a few comments about the mass M. If one focuses on usual physics, only the continuous limit counts and it has been shown in [22,23] that the mass M then vanishes. Thus, at the continuous limit, the DTQW under consideration describes the continuous dynamics of massless fermions. 3. Conclusions The computation of the Riemann tensor as the curvature of the spin connection coefficients using as gauge group the set of Lorentz transformations in spinor space does not deliver the usual space-time components of the tensor, but the so-called mixed components Rµνab, from which the usual space-time components can be recovered through partial contraction with the inverse n-bein coefficients. This applies both to the continuous and the discrete case. In 2D, there is only one independent component to the usual continuous Riemann tensor, and the discrete one also has only one independent component. We have proposed two different definitions of Riemann curvature for the DTQWs considered in this article. If one is mainly interested in quantum simulation of conventional continuous physics, the second definition, which makes use of slowly varying Lorentz transformations, is clearly the one of choice, if only because its continuous limit gives back the usual Riemann curvature of differential geometry. However, DTQWs are interesting in other contexts, for example in quantum computing and quantum algorithms, where the continuous limit is not necessarily of particular importance. It is therefore useful to develop, for these contexts, a very general notion of curvature which is not linked to what happens at the continuous limit or for slowly varying Lorentz transformations. This is why we have offered our first definition of Riemann curvature. For technicality reasons, the first definition makes it necessary to introduce a reference connection and the obtained Riemann curvature 14 of 16 14 of 16 Condens. Matter 2019, 4, 40 thus depends on this reference connection. In essence, the reference connection is the connection for which the first Riemann curvature vanishes. The easiest way to see this is to go back to Equation (72). This states that the first curvature of a connection is the difference between the second curvature of that connection and the second curvature of the reference connection. There is no canonical choice for the reference connection i.e., the reference connection must be chosen on case by case basis, according to the context and interests of the computation. The whole approach developed in this article is close in spirit to work which has been done in the last fifteen years, where classical Markov chains are used to define Ricci curvatures of graphs [37–39]. Indeed, a Markov chain is essentially a discrete diffusion. 3. Conclusions By definition, the DTQW does not describe known physics outside this limit i.e., in the discrete regime. In particular, we decided to call the matrix M the mass of the DTQW because the form (30) of the discrete equation resembles the form (6) of the continuous equation and the coefficient in front of Ψ in (6) is −i times the physical mass. However, this does not presuppose that the matrix M, outside the continuous limit, shares any property with physical masses. In particular, the two coefficients M− + and M+ −are not necessarily identical outside the continuous limit, where both vanish. In this sense, the matrix M should be considered as a generalised mass, which becomes a physical mass only at the continuous limit. Note that it is possible to construct DTQWs close to those considered in this article and whose continuous limits describe fermions of non vanishing mass (see, for example, [29]). Let us also recall that some DTQWs not considered in this manuscript have, even in the continuous regime, complex mass terms [23] which thus do not share the properties of physical masses. Let us now conclude by mentioning possible extensions of this work. One should first address more general DTQWs coupled to arbitrary Yang–Mills fields. The extension to both higher dimensional space-times and higher spins should also prove interesting, starting with walks defined on square lattices, then moving on to more general grids, the ultimate goal being DTQWs on graphs. For example: 15 of 16 Condens. Matter 2019, 4, 40 what are the necessary graph properties for a DTQW to define a curvature on the graph? Or, how can one use graph geometry to write more efficient quantum algorithms? One should finally extend all these computations to alternate, comparable discrete models such as Lattice Gauge Theories (LGTs) and compare the results with those obtained for DTQWs. Funding: This research received no external funding. Funding: This research received no external funding. Acknowledgments: For R.D. Acknowledgments: For R.D. Conflicts of Interest: The author declares no conflict of interest. Conflicts of Interest: The author declares no conflict of interest. References 1. Feynman, R.P.; Hibbs, A.R. Quantum Mechanics and Path Integrals; International Series in Pure and Applied Physics; McGraw-Hill Book Company: New York, NY, USA, 1965. 1. Feynman, R.P.; Hibbs, A.R. Quantum Mechanics and Path Integrals; International Series in Pure and Applied Physics; McGraw-Hill Book Company: New York, NY, USA, 1965. . Feynman, R.P.; Hibbs, A.R. Quantum Mechanics and Path Integrals; International Series in Pure and App . Feynman, R.P.; Hibbs, A.R. Quantum Mechanics and Path Integrals; International Series in Pure and App Physics; McGraw-Hill Book Company: New York, NY, USA, 1965. Aharonov, Y.; Davidovich, L.; Zagury, N. Quantum random walks. Phys. Rev. A 1993, 48, 1687. [CrossRef] Meyers, D.A.T. From quantum cellular automata to quantum lattice gases. J. Stat. Phys. 1996, 85, 551–574. 4. Schmitz, H.; Matjeschk, R.; Schneider, C.; Glueckert, J.; Enderlein, M.; Huber, T.; Schaetz, T. Quantum Walk of a Trapped Ion in Phase Space. Phys. Rev. Lett. 2009, 103, 090504. [CrossRef] 4. Schmitz, H.; Matjeschk, R.; Schneider, C.; Glueckert, J.; Enderlein, M.; Huber, T.; Schaetz, T. Quantum Walk of a Trapped Ion in Phase Space. Phys. Rev. Lett. 2009, 103, 090504. [CrossRef] pp p y 5. Zähringer, F.; Kirchmair, G.; Gerritsma, R.; Solano, E.; Blatt, R.; Roos, C.F. Realization of a Quantum Walk with One and Two Trapped Ions. Phys. Rev. Lett. 2010, 104, 100503. [PubMed] 5. Zähringer, F.; Kirchmair, G.; Gerritsma, R.; Solano, E.; Blatt, R.; Roos, C.F. Realization of a Quantum Walk with One and Two Trapped Ions. Phys. Rev. Lett. 2010, 104, 100503. [PubMed] 6. Schreiber, A.; Cassemiro, K.N.; Poto˘cek, V.; Gábris, A.; Mosley, P.J.; Andersson, E.; Jex, I.; Silberhorn, C. Photons Walking the Line: A quantum walk with adjustable coin operations. Phys. Rev. Lett. 2010, 104, 050502. [CrossRef] [PubMed] 7. Karski, M.; Förster, L.; Cho, J.M.; Steffen, A.; Alt, W.; Meschede, D.; Widera, A. Quantum Walk in Position Space with Single Optically Trapped Atoms. Science 2009, 325, 174–177. [CrossRef] 8. Sansoni, L.; Sciarrino, F.; Vallone, G.; Mataloni, P.; Crespi, A.; Ramponi, R.; Osellame, R. Two-Particle Bosonic-Fermionic Quantum Walk via Integrated Photonics. Phys. Rev. Lett. 2012, 108, 010502. [CrossRef] [PubMed] 9. Sanders, B.C.; Bartlett, S.D.; Tregenna, B.; Knight, P.L. Quantum quincunx in cavity quantum electrodynamics. Phys. Rev. A 2003, 67, 042305. [CrossRef] 10. Perets, H.B.; Lahini, Y.; Pozzi, F.; Sorel, M.; Morandotti, R.; Silberberg, Y. Realization of Quantum Walks with Negligible Decoherence in Waveguide Lattices. Phys. Rev. Lett. 2008, 100, 170506. [PubMed] 11. References Ambainis, A. Quantum walk algorithm for element distinctness. SIAM J. Comput. 2007, 37, 210–239. 12. Magniez, F.; Nayak, A.; Roland, J.; Santha, M. Search via quantum walk. SIAM J. Comput. 2007, 575 13. Aslangul, C. Quantum dynamics of a particle with a spin-dependent velocity. J. Phys. A 2005, 38, 1–16. [CrossRef] 14. Bose, S. Quantum Communication through an Unmodulated Spin Chain. Phys. Rev. Lett. 2003, 91, 207901. [CrossRef] [PubMed] 15. Burgarth, D. Quantum State Transfer with Spin Chains. Ph.D. Thesis, University College London, London, UK, 2006. 16. Bose, S. Quantum Communication through Spin Chain Dynamics: An Introductory Overview. Contemp. Phys. 2007, 48, 13–30. [CrossRef] 17. Di Molfetta, G.; Debbasch, F.; Brachet, M. Non-linear optical Galton board: Thermalization and continuous limit. Phys. Rev. E 2015, 92, 042923. [CrossRef] 18. Hatifi, M.; Di Molfetta, G.; Debbasch, F.; Brachet, M. Quantum walk hydrodynamics. Sci. Rep. 2019, 9, 2989. [CrossRef] [PubMed] 19. Collini, E.; Wong, C.Y.; Wilk, K.E.; Curmi, P.M.G.; Brumer, P.; Scholes, G.D. Coherently wired light-harvesting in photosynthetic marine algae at ambient temperature. Nature 2010, 463, 644–647. [CrossRef] 20. Engel, G.S.; Calhoun, T.R.; Read, R.L.; Ahn, T.-K.; Manal, T.; Cheng, Y.-C.; Blankenship, R.E.; Fleming, G.R. Evidence for wavelike energy transfer through quantum coherence in photosynthetic systems. Nature 2007, 446, 782–786. [CrossRef] 21. Cedzich, C.; Rybár, T.; Werner, A.H.; Alberti, A.; Genske, M.; Werner, R.F. Propagation of Quantum Walks in Electric Fields. Phys. Rev. Lett. 2013, 111, 160601. [CrossRef] 16 of 16 16 of 16 Condens. Matter 2019, 4, 40 22. Di Molfetta, G.; Brachet, M.; Debbasch, F. Quantum walks as massless Dirac fermions in curved space-time. Phys. Rev. A 2013, 88, 042301. [CrossRef] 23. Di Molfetta, G.; Brachet, M.; Debbasch, F. Quantum walks in artificial electric and gravitational Fields. Phys. A 2008, 397, 157–168. [CrossRef] 24. Arrighi, P.; Facchini, S.; Forets, M. Quantum walking in curved spacetime. Quantum Inf. Process. 2016, 15, 3467–3486. [CrossRef] 25. Arnault, P.; Debbasch, F. Landau Levels for discrete time quantum walks in artificial magnetic fields. Phys. A 2016, 443, 179–191. [CrossRef] 26. Bru, L.A.; Hinarejos, M.; Silva, F.; de Valcárcel, G.J.; Roldán, E. Electric quantum walks in two dimensions. Phys. Rev. A 2016, 93, 032333. [CrossRef] 27. Arnault, P.; Debbasch, F. Quantum walks and discrete gauge theories. Phys. Rev. A 2016, 93, 052301. [CrossRef] 28. Arrighi, P.; Patricot, C. Quantum walking in curved spacetime: (3+1) dimensions, and beyond. arXiv 2016, arXiv:1609.00305v2. 29. Arnault, P.; Debbasch, F. References Quantum walks and gravitational waves. Ann. Phys. 2017, 383, 645–661. [Cr 29. Arnault, P.; Debbasch, F. Quantum walks and gravitational waves. Ann. Phys. 2017, 383, 645–661. [CrossRef] 30. Cedzich, C.; Geib, T.; Werner, A.H.; Werner, R.F. Quantum walks in external gauge fields. J. Math. Phys. 2019, 60, 012107. [CrossRef] 30. Cedzich, C.; Geib, T.; Werner, A.H.; Werner, R.F. Quantum walks in external gauge fields. J. Math. Phys. 2019, 60, 012107. [CrossRef] 31. Genske, M.; Alt, W.; Steffen, A.; Werner, A.H.; Werner, R.F.; Meschede, D.; Alberti, A. Electric Quantum Walks with Individual Atoms. Phys. Rev. Lett. 2013, 110, 190601. [CrossRef] 32. Wald, R.M. General Relativity; The University of Chicago Press: Chicago, IL, USA, 1984. 33. Yepez, J. Einstein’s Vierbein Field Theory of Curved Space. arXiv 2011, arXiv:1106.2037v1. 34. Arminjon, M.; Reifler, F. Equivalent forms of Dirac equations in curved spacetimes and generalized de Broglie relations. Braz. J. Phys. 2013, 43, 64–77. [CrossRef] 35. Pollock, M.D. On the Dirac equation in curved space-time. Acta Phys. Polon. B 2013, 41, 1827. 36. Debbasch, F. Action Principles for Quantum Automata and Lorentz Invariance of Discrete Time Quantum Walks. arXiv 2018, arXiv:1806.02313. 37. Ollivier, Y. A survey of Ricci curvature for metric spaces and Markov chains. Adv. Stud. Pure Math. 2010, 57, 343–381. 8. Ollivier, Y. Ricci curvature of Markov chains on metric spaces. Funct. Anal. 2009, 256, 810–864. [CrossR livier, Y. Ricci curvature of Markov chains on metric spaces. Funct. Anal. 2009, 256, 810–864. [CrossRef] b M M J Ri i C t f Fi it M k Ch i i C it f th E t A h R ti 38. Ollivier, Y. Ricci curvature of Markov chains on metric spaces. Funct. Anal. 2009, 256, 810–864. [CrossRef] 39. Erbar, M.; Maas, J. Ricci Curvature of Finite Markov Chains via Convexity of the Entropy. Arch. Ration. Mech. Anal. 2012, 206, 997–1038. [CrossRef] Erbar, M.; Maas, J. Ricci Curvature of Finite Markov Chains via Convexity of the Entropy. Arch. Ration Mech. Anal. 2012, 206, 997–1038. [CrossRef] c⃝2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
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Forest mapping and species composition using supervised per pixel classification of Sentinel-2 imagery
Biotechnologie, agronomie, société et environnement
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B A S E B A S E B A Biotechnol. Agron. Soc. Environ. 2018 22(3) S E de l’Ardenne belge, espèces d’arbre, télédétection, satellite, classification par pixel, forêt aléatoire. Mots-clés. Écorégion de l’Ardenne belge, espèces d’arbre, télédétection, satellite, classification par Forest mapping and species composition using supervised per pixel classification of Sentinel-2 imagery Corentin Bolyn, Adrien Michez, Peter Gaucher, Philippe Lejeune, Stéphanie Bonnet Université de Liège - Gembloux Agro-Bio Tech. TERRA Forest is life. Passage des Déportés, 2. BE-5030 Gembloux (Belgium). E-mail: p.lejeune@uliege.be Corentin Bolyn, Adrien Michez, Peter Gaucher, Philippe Lejeune, Stéphanie Bonnet Université de Liège - Gembloux Agro-Bio Tech. TERRA Forest is life. Passage des Déportés, 2. BE-5030 Gembloux (Belgium). E-mail: p.lejeune@uliege.be Received 20 December 2017, accepted 20 June 2018, available online 6 August 2018. This article is distributed under the terms and conditions of the CC-BY License (http://creativecom Description of the subject. Understanding the current situation and evolution of forests is essential for a sustainable management plan that maintains forests’ ecological and socio-economic functions. Remote sensing is a helpful tool in developing this knowledge. Objectives. This paper investigates the new opportunities offered by using Sentinel-2 (S2) imagery for forest mapping in Belgian Ardenne ecoregion. The first classification objective was to create a forest map at the regional scale. The second objective was the discrimination of 11 forest classes (Fagus sylvatica L., Betula sp., Quercus sp., other broad-leaved stands, Pseudotsuga menziesii (Mirb.) Franco, Larix sp., Pinus sylvestris L., Picea abies (L.) H.Karst., young needle-leaved stands, other needle-leaved stands, and recent clear-cuts). Method. Two S2 scenes were used and a series of spectral indices were computed for each. We applied supervised pixel-based classifications with a Random Forest classifier. The classification models were processed with a pure S2 dataset and with additional 3D data to compare obtained precisions. Results. 3D data slightly improved the precision of each objective, but the overall improvement in accuracy was only significant for objective 1. The produced forest map had an overall accuracy of 93.3%. However, the model testing tree species discrimination was also encouraging, with an overall accuracy of 88.9%. Conclusions. Because of the simple analyses done in this study, results need to be interpreted with caution. However, this paper confirms the great potential of S2 imagery, particularly SWIR and red-edge bands, which are the most important S2 bands in our study. i n Ardenne ecoregion, tree species, remote sensing, satellites, per-pixel classification, random forest. Keywords. Belgian Ardenne ecoregion, tree species, remote sensing, satellites, per-pixel classificat 1. INTRODUCTION & Marine Monitoring, Climate Change, Security & Emergency Management Services). The launch of the two Sentinel-2 (S2) satellites is an opportunity to enhance forest characterization on a large scale. The satellites multispectral 13-band sensors produce high- quality images at a 5-day equatorial temporal resolution (Suhet & Hoersch, 2015). Such an availability of free data is unprecedented and will substantially promote research in this topic. & Marine Monitoring, Climate Change, Security & Emergency Management Services). The launch of the two Sentinel-2 (S2) satellites is an opportunity to enhance forest characterization on a large scale. The satellites multispectral 13-band sensors produce high- quality images at a 5-day equatorial temporal resolution (Suhet & Hoersch, 2015). Such an availability of free data is unprecedented and will substantially promote research in this topic. Forest ecosystems provide important services to society, and sustainable management and adapted policies are essential to maintain their ecological and socio-economic functions. Forest managers and policy makers must consider the relationships between forest function and ecosystem characteristics and the evolution of forests in order to manage forests and make regional decisions (Führer, 2000; Lindenmayer et al., 2000). Given the globalization of today’s society, this need has become even more important, as understanding forests is important for international agreements and reporting requirements (e.g. the Kyoto Protocol). i In preparation for the arrival of the new S2 imagery, Inglada et al. (2017) present a methodology to automatize the production of a land cover map at the country scale using high-resolution optical image time series. Using this methodology, the study constructs a map of metropolitan France with a coefficient of kappa 0.86 describing 17 land cover classes, including broad-leaved forest and coniferous forest. In the first study to use pre-operational S2 data, Immitzer et al. (2016) test both a pixel-and object-based classification of tree species in Germany for 7 classes, getting an overall accuracy (OA) of 0.64 and 0.66, respectively. These studies demonstrate the powerful potential of satellite imagery for forest mapping, and research is necessary to exploit the potential of these new S2 data. In their review of tree species classification studies, Fassnacht et al. (2016) observe the increasing number of works on this topic over the last 40 years. However, they note that most investigations are oriented toward optimizing classification accuracy over a relatively small test site and it is therefore often difficult to draw general conclusions from these studies. 1. INTRODUCTION The authors recommend using well-defined applications in future research in order to avoid purely data-driven studies of limited values and increase understanding of broader factors affecting tree species classification. For decades, field inventories have been used to better characterize forest. National inventories exist in countries around the world and have evolved over time to adapt to users’ needs (Tomppo et al., 2010). Field inventories provide timely and accurate estimates of forest resources and their evolution at a large scale. Nevertheless, this method is time-consuming and quite expensive. Furthermore, an inventory of an entire area is, for obvious reasons, impossible and sample-based procedures are necessary. Therefore, technological innovation is becoming crucial to improve the efficiency of measurements and estimations while making the production of inventory data simpler (McRoberts & Tomppo, 2007). Remote sensing is one of the technological tools at our disposal: it decreases the cost of data acquisition, increases the area it is possible to cover without sampling, and enables the production of high-resolution forest attribute maps. Remote sensing enables the production of map layers that give precious information about the distribution of forest resources. These complement sample-based procedures in the field and today are commonly used by researchers and managers (McDermid et al., 2009). In this context, we use S2 imagery to investigate image classification in European temperate forests at the regional scale. Our study has three goals: – to create a highly accurate regional forest map using S2 imagery; g Today advances in technology such as satellite remote sensing and digital photogrammetry have increased the possible applications of remote sensing and image classification. Light detection and ranging (LiDAR) data and photogrammetry technologies have made it possible to use 3D data, such as Canopy Height Models (CHM) when investigating forests. These technologies improve the classification accuracy of forest classes (Waser et al., 2011). However, 3D data is still rare at the large scale and the technology remains expensive. – to evaluate the potential of S2 imagery in identifying the main tree species encountered in the study area;i – to assess the benefits of incorporating 3D data into our study of the previous two goals and therefore determining how precise S2 data is in these approaches. For these purposes, we implemented supervised classification per pixel using a random forest (RF) algorithm. We used two S2 images acquired at different dates to take account for species seasonality. stière et composition spécifique par classification supervisée par pixel d’imagerie Sentinel-2 É Bolyn C., Michez A., Gaucher P. et al. Biotechnol. Agron. Soc. Environ. 2018 22(3) 2 stière et composition spécifique par classification supervisée par pixel d’imagerie Sentinel-2 É Cartographie forestière et composition spécifique par classification supervisée par pixel d’imagerie Sentinel-2 Description du sujet. Étudier l’état et l’évolution des forêts est essentiel pour assurer une gestion durable maintenant leurs fonctions écologiques et socio-économiques. La télédétection est un outil précieux pour le développement de ces connaissances. Objectifs. Cette étude analyse l’opportunité offerte par l’imagerie Sentinel-2 (S2) pour cartographier les forêts de l’écorégion de l’Ardenne belge. Le premier objectif de classification était la création d’une carte forestière à l’échelle régionale. Le second objectif était la discrimination de 11 classes forestières (Fagus sylvatica L., Betula sp., Quercus sp., other broad-leaved stands, Pseudotsuga menziesii (Mirb.) Franco, Larix sp., Pinus sylvestris L., Picea abies (L.) H.Karst., young needle-leaved stands, other needle-leaved stands, and recent clear-cuts). Méthode. Deux scènes S2 ont été utilisées et une série d’indices spectraux ont été générés pour chacune d’entre elles. Nous avons réalisé une classification supervisée par pixel avec l’algorithme de classification Random Forest. Les modèles de classification ont été générés avec un jeu de données S2 pur et avec des données 3D supplémentaires pour comparer les précisions obtenues. p Résultats. Les données 3D ont légèrement amélioré la précision de chaque objectif, mais l’amélioration globale de précision fut uniquement significative pour l’objectif 1. La carte forestière produite avait une précision globale de 93,3 %. Le modèle testant la discrimination des espèces d’arbre fut encourageant également, avec une précision globale de 88,9 %. Conclusions. Tenant compte des simples analyses réalisées dans cette étude, les résultats doivent être interprétés avec prudence. Cependant, ce travail confirme le grand potentiel de l’imagerie S2, particulièrement les bandes SWIR et red-edge, qui jouèrent un rôle essentiel dans ce travail. p Résultats. Les données 3D ont légèrement amélioré la précision de chaque objectif, mais l’amélioration globale de précision fut uniquement significative pour l’objectif 1. La carte forestière produite avait une précision globale de 93,3 %. Le modèle testant la discrimination des espèces d’arbre fut encourageant également, avec une précision globale de 88,9 %. Conclusions Tenant compte des simples analyses réalisées dans cette étude les résultats doivent être interprétés avec prudence Conclusions. Tenant compte des simples analyses réalisées dans cette étude, les résultats doivent être interprétés avec prudence. Cependant, ce travail confirme le grand potentiel de l’imagerie S2, particulièrement les bandes SWIR et red-edge, qui jouèrent un rôle essentiel dans ce travail Mots-clés. Écorégion de l’Ardenne belge, espèces d’arbre, télédétection, satellite, classification par pixel, forêt aléatoire. 1. INTRODUCTION Then, we computed a range of spectral indices. After a step of variables selection, we trained random forest classifiers for two datasets: the first contains only S2 bands and spectral indices, while the second also contains 3D data. The quality of the results was assessed and This may be different for satellite imagery. On 28 February 2008, the European Union (EU) and European Space Agency (ESA) signed an agreement over the creation of the COPERNICUS program. The aim of this program is to provide earth surface monitoring services (European Commission, 2015) (Land, Atmosphere 3 Forest mapping with Sentinel-2 imagery compared in terms of a confusion matrix with a strong reference dataset. compared in terms of a confusion matrix with a strong reference dataset. time naturally regenerated and thus present an uneven- aged structure and a composition dominated by beech and oak, the level of mixture being driven mainly by soil depth and topography. Figure 1 provides an overview of the study site. 2.1. Study site Sentinel-2. The onboard S2 sensor is a passive multi- spectral instrument (MSI). It provides 13 spectral bands (Table 1). In order to simplify pre-processing, the only two available S2 images with less than 10% cloud cover over the entire Ardenne ecoregion were selected. Their sensing times were 2 August 2015 and 8 May 2016 (further referred as D1 and D2). These dates have a potential interest as they could help to difference some broad-leaved species between themselves or from resinous species. Indeed in this region, in May, Fagus sylvatica and Betula sp. have begun foliation period since more than a month while Quercus sp. have just started (https://fichierecologique. be). It is widely acknowledged that reflectance from the Earth’s surface, called top-of-atmosphere (TOA), is significantly modified by the atmosphere (Jensen, 2005; Lillesand et al., 2008; Richards, 2013). There are many remote sensing studies that have investigated how to The study was conducted for the entire Belgian Ardenne ecoregion. This region constitutes a plateau whose altitude increases gradually from the South- West to the North-East, culminating at nearly 700 m. The annual mean temperature is smaller than 9 °C and annual precipitations are nearly 1,200 mm. With an afforestation rate of 58%, the Ardenne represents 333,850 ha of forest and is the largest forest area in Wallonia. This forest is mainly coniferous (64%), according to Wallonia’s Regional Forest Inventory (RFI) (Alderweireld et al., 2015), and the most frequently found tree species are (in order of quantity): spruce (Picea abies [L.] H.Karst.), oak (Quercus sp.), beech (Fagus sylvatica L.), Douglas fir (Pseudotsuga menziesii (Mirb.) Franco), pine (Pinus sp.), and larch (Larix sp.). These six species represent 85.8 % of the forest. Most of the time, coniferous stands are pure species plantations. Deciduous stands are most of the Figure 1. The study area, the Belgian Ardenne ecoregion, is shown in yellow. A more detailed view is presented in the top left corner (orthophoto 2016, Public Service of Wallonia) — La zone d’étude, l’écorégion de l’Ardenne belge, est en jaune. Une vue plus détaillée est présentée dans le coin supérieur gauche (orthophoto 2016, Service Public de Wallonie). 0 5 10 20 30 40 km N 4°0’0’’E 4°30’0’’E 5°0’0’’E 5°30’0’’E 6°0’0’’E 6°30’0’’E 50°0’0’’N 50°20’0’’N 50°40’0’’N 5°0’0’’E 5°30’0’’E 6°30’0’’E Figure 1. The study area, the Belgian Ardenne ecoregion, is shown in yellow. 2.1. Study site A more detailed view is presented in the top left corner (orthophoto 2016, Public Service of Wallonia) — La zone d’étude, l’écorégion de l’Ardenne belge, est en jaune. Une vue plus détaillée est présentée dans le coin supérieur gauche (orthophoto 2016, Service Public de Wallonie). Bolyn C., Michez A., Gaucher P. et al. Biotechnol. Agron. Soc. Environ. 2018 22(3) 4 reduce the effects of the atmosphere on the signal (Kaufman et al., 1997; Song et al., 2001; Guanter et al., 2008). This is even more important in case of multi-temporal date analyses (Agapiou et al., 2011; Hagolle et al., 2015), therefore we used the atmospheric correction proposed by the Sen2Cor processor (version 2.2.) (Müller-Wilm, 2016). Hence, Level-1C data were processed into Level- 2A (bottom-of-atmosphere corrected reflectance images). S2 bands at 20 m of spatial resolution were resampled at 10 m during this step (nearest neighbor method). Then we compiled a layer stack of 20 spectral bands with D1 and D2. Table 1. Sentinel-2 bands properties, band number, band name in this study, central wavelength (nm), bandwidth (nm), spatial resolution (m) and purpose. Only ban numbers marked with asterisks were used in this study. Data compilation and purpose from the European Space Agency (2015) — Propriétés des bandes S2, numéro d la bande, nom de la bande dans cette étude, longueur d’onde centrale (nm), largeur de la bande (nm), résolution spatiale (m) et objectif. Seuls les numéros de bande annotés avec une astérisque ont été utilisés dans cette étude. Données et objectifs provenant de European Space Agency (2015). Band number Band name Central wavelength (nm) Bandwidth (nm) Spatial resolution (m) Purpose 2 * Blue 490 65 10 Blue 3 * Green 560 35 10 Green 4 * Red 665 30 10 Red 8 * NIRwide 842 115 10 Sensitive to chlorophyll, biomass and protein 5 * Rededge 1 705 15 20 Vegetation Classification 6 * Rededge 2 740 15 20 Vegetation Classification 7 * Rededge 3 786 20 20 Vegetation Classification 8a * NIRnarrow 865 20 20 Vegetation Classification 11 * SWIR 1 1,610 90 20 Sensitive to lignin, starch and forest above ground biomas 12 * SWIR 2 2,190 180 20 Distinction of live biomass, dead biomass and soil 1 - 443 20 60 Aerosol scattering 9 - 945 20 60 Water vapor absorption 10 - 1,375 20 60 Detection of thin cirrus Table 1. 2.1. Study site Sentinel-2 bands properties, band number, band name in this study, central wavelength (nm), bandwidth (nm), spatial resolution (m) and purpose. Only b numbers marked with asterisks were used in this study. Data compilation and purpose from the European Space Agency (2015) — Propriétés des bandes S2, numéro la bande, nom de la bande dans cette étude, longueur d’onde centrale (nm), largeur de la bande (nm), résolution spatiale (m) et objectif. Seuls les numéros de ban annotés avec une astérisque ont été utilisés dans cette étude. Données et objectifs provenant de European Space Agency (2015). Band number Band name Central wavelength (nm) Bandwidth (nm) Spatial resolution (m) Purpose 2 * Blue 490 65 10 Blue 3 * Green 560 35 10 Green 4 * Red 665 30 10 Red 8 * NIRwide 842 115 10 Sensitive to chlorophyll, biomass and protein 5 * Rededge 1 705 15 20 Vegetation Classification 6 * Rededge 2 740 15 20 Vegetation Classification 7 * Rededge 3 786 20 20 Vegetation Classification 8a * NIRnarrow 865 20 20 Vegetation Classification 11 * SWIR 1 1,610 90 20 Sensitive to lignin, starch and forest above ground biom 12 * SWIR 2 2,190 180 20 Distinction of live biomass, dead biomass and soil 1 - 443 20 60 Aerosol scattering 9 - 945 20 60 Water vapor absorption 10 - 1,375 20 60 Detection of thin cirrus 3.1. Image classification models To accomplish our first two goals, we defined two models of classification. The model called Objective 1 created a forest map, and was trained to identify four classes: broad-leaved stands, coniferous stands, recent clear-cuts, and non-forest areas. The non-forest class dataset contained an equal proportion of observations for agricultural lands, urban landscapes, and water bodies. In order to create our forest map, we applied the obtained classifier to the entire study area. We then generated a forest land use map by merging the three forest classes into one. By first growing a model with four classes, clear cuts are integrated into the produced forest map, as it forms an integral part of the forest estate covered by management plans. DFU were used for both Objectives 1 and 2 to extract reference data for forest classes. Before that, DFU polygons were visually interpreted to verify eventual errors or modifications since the last update. For each class, the chosen forest stands were supposed to be “pure stands” according to the DFU database (percentage > 80%). Table 3 shows by class the number of polygons and the number of extracted pixels. Reference polygons were delineated for non- forest classes by visual interpretation of orthophotos. Detection of thin cirrus 3D data. Three Canopy Height Models (CHM) and one slope layer, based on LiDAR and photogrammetric point clouds, were used covering the entire study area at a resolution of 1 m. A CHM was made using LiDAR (LiDAR DSM - LiDAR DTM) and referred to as CHM3 in this paper. The average point density of small footprint discrete airborne Lidar data was 0.8 points.m-1. Survey flights were realized by the Public Service of Wallonia from 12 December 2012 to 21 April 2013 and from 20 December 2013 to 9 March 2014. The survey covered Wallonia with a regional digital terrain model (1 m ground sampling distance [GSD]). A digital surface model (DSM) at the same resolution was also computed and a slope layer was generated based on the Lidar digital terrain model (DTM). For two other CHMs, raw images from two regional orthophoto datasets (acquired by the Public Service of Wallonia) were used to generate two high-density photogrammetric point clouds. Both survey flights took place between April and September, the first in 2006 and 2007 (0.50 m GSD), the second in 2009 and 2010 (0.25 m GSD). Considering that the regional topography did not change significantly, hybrid CHMs were computed using photogrammetric DSM and LiDAR DTM, as described above, following the approach of Michez et al. (2017) (photogrammetric DSM-LiDAR DTM). Their spatial resolution is 1 m. The precision of this approach has been evaluated in Michez et al. (2017) using field tree height measurements (root mean square error smaller than 3 m). These hybrids CHM are called CHM1 and CHM2 in this paper. They were used in this study to improve the detection of recent clear cuts and young stands, adding height information in the past. These four layers (CHM1, CHM2, CHM3, and SLOPE) were aggregated at 10 m of spatial resolution using median value. 5 Forest mapping with Sentinel-2 imagery 3. METHODS from four bands (RGB and IR) 0.25 m resolution orthophotos covering the entire region. These image layers are available for the years 2006, 2009, 2012, and 2015 (http://geoportail.wallonie.be). 3.3. Variable selection and classification The following steps were executed in the same way for Objectives 1 and 2 using Dataset 1 or 2 (Figure 2). Before building classification models, we rationally reduced the number of variables by selecting the most important using VSurf (Genuer et al., 2016) in R software (R Core Team, 2016). The VSurf package allows variable selection based on the estimation of RF’s variable importance (Genuer et al., 2015). As a result, the process provides two variables subsets. The first, called “variable interpretation”, is intended to show variables highly related to the response variable. It does not matter if there is some, or even much, redundancy in this subset. The second, called “prediction”, is a smaller subset with low redundancy intended to assure a good prediction of the response variable. y g p Second model called Objective 2 aims at classifying the tree species present in the study site to evaluate the discrimination potential of S2 data using a pixel-based approach. Based on the RFI, we defined 11 classes that corresponds to the main species or types of stands: beech, birch (Betula sp.), oak, other broad-leaved stands (OB), Douglas fir, larch, Scots pine (Pinus sylvestris L.), spruce, young needle-leaved stands (YN), other needle-leaved stands (ON), and recent clear-cuts (RCC). Young stands correspond to plantations between 4 and 12 years old, and recent clear-cuts are stands that have been harvested in the last four years. For each class, pixels contain at least 80% of the species or group of species. The global workflow of the study is synthesized in figure 2. The following parameters were set to allow the maximum performance in a reasonable time with the used computer: 3.2. Dataset preparation After a step of variables selection, random forest classif were trained for two datasets: the first contained only S2 bands and spectral indices (Dataset S2), while the second a contained 3D data (Dataset S2-3D) — Workflow global de l’étude divisé en deux objectifs de classification. Le premier mod de classification nommé Objectif 1 a généré une carte forestière et a été entrainé à identifier quatre classes : les peupleme feuillus, les peuplements résineux, les coupes rases récentes et les surfaces non forestières. Le second modèle nommé Object visait à classifier les espèces d’arbre présentes sur le site d’étude afin d’évaluer le potentiel discriminant des données S2 une approche par pixel. Après une étape de sélection de variables, des forêts aléatoires ont été entrainées pour deux jeux données : le premier contenant uniquement les bandes S2 et des indices spectraux (Dataset S2), le second incluant aussi d données 3D (Dataset S2-3D). Reference data Reference polygons Dataset S2 Dataset S2-3D Sentinel 2 layer stack 10 m, D1 and D2 Indices production 3D data inclusion - 1 lidar CHM - 2 photogrammetric CHM’s Pixels extraction 10% for validation data Objectif 2 90% for training data 100% for training data Objectif 1 VSurf variable selection VSurf variable selection RF Pixel based classification RF Pixel based classification Independent validation for each dataset Independent validation for each dataset Forest cover map Independent validation Visual interpretation of a systematic grid Application of the best model and post-treatment Sentinel 2 layer stack 10 m, D1 and D2 Reference data 3D data inclusion - 1 lidar CHM - 2 photogrammetric CHM’s Indices production Dataset S2-3D Dataset S2 Reference polygons 10% for validation data Pixels extraction 90% for training data 100% for training data Objectif 1 Objectif 2 VSurf variable selection RF Pixel based classification RF Pixel based classification Visual interpretation of a systematic grid Independent validation for each dataset Independent validation for each dataset Independent validatio for each dataset Application of the best model and post-treatment Forest cover map Independent validation Figure 2. Global workflow of the study divided in two goals of classification. The first classification model called Objective 1 created a forest map, and was trained to identify four classes: broad-leaved stands, coniferous stands, recent clear-cuts, and non-forest areas. Second model called Objective 2 aimed at classifying the tree species present in the study site to evaluate the discrimination potential of S2 data using a pixel-based approach. 3.2. Dataset preparation – each RF was built using ntree = 1,000 trees, the number of variables randomly sampled as candidates at each split (mtry) was set by default (sqrt[p], where p is the number of variables); In order to determine the most pertinent classification variables in each model, we added a large selection of spectral indices to the original S2 dataset. Each indice was generated for D1 and D2. The list is presented in table 2. – the number of random forests grown was 20 for the three main steps of the Vsurf process: “thresholding step”, “interpretation step”, and “prediction step” (nfor.thres = 20, nfor.interp = 20 and nfor.pred = 20); We then created another dataset that include 3D data and compared results of the two datasets for each classification objective. In other words, for each objective we tested the following datasets: the S2 bottom-of-atmosphere data D1 and D2 with spectral indices (S2) and the S2 bottom-of-atmosphere data D1 and D2 with spectral indices and 3D data (S2-3D). – the mean jump is the threshold of decreasing mean OOB error used in the Vsurf’s prediction step to add variables to the model in a stepwise manner. It was multiplied 4 times (nmj = 4) in order to make this step more selective, considering the large number of variables. All together, there were 10 S2 Bands, 34 indices by sensing time, 3 CHM dates, and 1 slope layer. So, depending on whether we included 3D data, we had 89 or 93 variables by dataset. For the two objectives, we realized supervised classifications per pixel with a RF classifier (Breiman, 2001), using the randomForest package (Liaw & Wiener, 2002) in R software (R Core Team, 2016). Only the variables selected during the prediction step Reference pixels were produced from delineated management forest units (DFU) extracted from the regional forest administration geodatabase and Biotechnol. Agron. Soc. Environ. 2018 22(3) Bolyn C., Michez A., Gaucher P. et al. 6 Figure 2. Global workflow of the study divided in two goals of classification. The first classification model called Objectiv created a forest map, and was trained to identify four classes: broad-leaved stands, coniferous stands, recent clear-cuts, a non-forest areas. Second model called Objective 2 aimed at classifying the tree species present in the study site to evaluate discrimination potential of S2 data using a pixel-based approach. 3.2. Dataset preparation After a step of variables selection, random forest classifiers were trained for two datasets: the first contained only S2 bands and spectral indices (Dataset S2), while the second also contained 3D data (Dataset S2-3D) — Workflow global de l’étude divisé en deux objectifs de classification. Le premier modèle de classification nommé Objectif 1 a généré une carte forestière et a été entrainé à identifier quatre classes : les peuplements feuillus, les peuplements résineux, les coupes rases récentes et les surfaces non forestières. Le second modèle nommé Objectif 2 visait à classifier les espèces d’arbre présentes sur le site d’étude afin d’évaluer le potentiel discriminant des données S2 via une approche par pixel. Après une étape de sélection de variables, des forêts aléatoires ont été entrainées pour deux jeux de données : le premier contenant uniquement les bandes S2 et des indices spectraux (Dataset S2), le second incluant aussi des données 3D (Dataset S2-3D). Forest mapping with Sentinel-2 imagery 7 Table 2. List of spectral indices generated for D1 (2 August 2015) and D2 (8 May 2016) S2 images — Liste des indices spectraux générés pour les images S2 D1 (2 aou 2015) et D2 (8 mai 2016). Indice Name Formula References BAI Built-up Area Index Blue - NIRnarrow Blue + NIRnarrow Shahi et al., 2015 Chlogreen Chlorophyll Green index NIRnarrow Green + Rededge1 Datt, 1999 GEMI Global Environment Monitoring Vegetation Index n x (1 - 0.25n) -Red - 0.125 1-Red n = 2 x (NIRnarrow2 - Red2) + 1.5 x NIRnarrow + 0.5 x Red NIRnarrow + Red + 0.5 Pinty & Verstraete, 1992 GI Greenness Index Green Red le Maire et al., 2004 gNDVI Green normalized difference vegetation index NIRnarrow - Green NIRnarrow + Green Gitelson et al., 1996 LAnthoC Leaf Anthocyanid Content Rededge3 Green - Rededge1 Wulf & Stuhler, n.d. LCaroC Leaf Carotenoid Content Rededge3 Blue - Rededge1 Wulf & Stuhler, n.d. LChloC Leaf Chlorophyll Content Rededge3 Rededge1 Wulf & Stuhler, n.d. 3.2. Dataset preparation MSI Moisture stress index SWIR1 NIRnarrow Vogelmann & Rock, 1985 NDrededgeSWIR Normalized Difference of Red-edge and SWIR2 Rededge2 - SWIR2 Rededge2 + SWIR2 Radoux et al., 2016 NDTI Normalized Difference Tillage Index SWIR1 - SWIR2 SWIR1 + SWIR2 Van Deventer et al., 1997 NDVI Normalized difference vegetation index NIRnarrow -Red NIRnarrow+ Red Tucker; 1979 NDVIre Red-edge normalized difference vegetation index NIRnarrow - Rededge1 NIRnarrow + Rededge1 Gitelson et al., 1996 NDWI1 Normalized Difference Water Index 1 NIRnarrow - SWIR1 NIRnarrow + SWIR1 Gao, 1996 NDWI2 Normalized Difference Water Index 2 Green - NIRnarrow Green + NIRnarrow Gitelson et al., 1996 NHI Normalized Humidity Index SWIR1 - Green SWIR1 + Green Lacaux et al., 2007 Biotechnol. Agron. Soc. Environ. 2018 22(3) Bolyn C., Michez A., Gaucher P. et al. 8 Table 2 (continued). List of spectral indices generated for D1 (2 August 2015) and D2 (8 May 2016) S2 images — Liste des indices spectraux générés pour les image S2 D1 (2 aout 2015) et D2 (8 mai 2016). 3.2. Dataset preparation Indice Name Formula References Norm-G Normalized Green Green NIRwide + Red + Green Sripada et al., 2006 Norm-NIR Normalized Near Infra-red NIRwide NIRwide + Red + Green Sripada et al., 2006 Norm-R Normalized red Red NIRwide + Red + Green Sripada et al., 2006 RededgePeakArea Red-edge peak area Red + Rededge1 + Rededge2 + Rededge3 + NIRnarrow Filella & Penuelas, 1994 Radoux et al., 2016 RedSWIR1 Bands difference Red - SWIR1 Jacques et al., 2014 RTVIcore Red-edge Triangular Vegetation Index 100 x (NIRnarrow - Rededge1) - 10 x (NIRnarrow - Green) Chen et al., 2010 SAVI Soil Adjusted Vegetation Index NIRnarrow - Red NIRnarrow + Red + 0.5 x 1.5 Huete, 1988 SR-BlueRededge1 Simple Blue and Red-edge 1 Ratio Blue Rededge1 le Maire et al., 2004 SR-BlueRededge2 Simple Blue and Red-edge 2 Ratio Blue Rededge2 Lichtenthaler et al., 1996 SR-BlueRededge3 Simple Blue and Red-edge 3 Ratio Blue Rededge3 Radoux et al., 2016 SR-NIRnarrowBlue Simple ratio NIR narrow and Blue NIRnarrow Blue Blackburn, 1998 SR-NIRnarrowGreen Simple ratio NIR narrow and Green NIRnarrow Green le Maire et al., 2004 SR-NIRnarrowRed Simple ratio NIR narrow and Red NIRnarrow Red Blackburn, 1998 SR-NIRnarrowRededge1 Simple NIR and Red-edge 1 Ratio NIRnarrow Rededge1 Datt, 1999 SR-NIRnarrowRededge2 Simple NIR and Red-edge 2 Ratio NIRnarrow Rededge2 Radoux et al., 2016 SR-NIRnarrowRededge3 Simple NIR and Red-edge 3 Ratio NIRnarrow Rededge3 Radoux et al., 2016 STI Soil Tillage Index SWIR1 SWIR2 Van Deventer et al., 1997 WBI Water Body Index Blue - Red Blue + Red Domenech & Mallet, 2014 Forest mapping with Sentinel-2 imagery 9 Table 3. The number of DFU polygons and extracted pixels by forest class: recent clear cuts (RCC), beech, birch, oak, other broad-leaved stands (OB), Douglas fir, larch, other needle-leaved stands (ON), Scots pine, spruce, young needle-leaved stands (YN) — Nombre de polygones DFU et nombre de pixels extraits par classe forestière : coupes récentes (RCC), hêtre (beech), bouleau (birch), chêne (oak), autres peuplements feuillus (OB), Douglas (Douglas fir), mélèze (larch), autres peuplements résineux (ON), pin sylvestre (Scots pine), épicéa (spruce), jeunes peuplements résineux (YN). RCC Beech Birch Oak OB Douglas fir Larch ON Scots pine Spruce YN Number of polygons 51 64 57 37 34 46 44 45 33 31 47 Number of pixels 7,068 6,327 2,589 4,572 3,623 5,929 5,799 3,251 4,180 4,028 3,858 of VSurf were considered for this classification. 3.4. Accuracy assessment All the reference data extracted from DFU polygons were used to train Objective 1. The accuracy assessment was carried out with a set of points systematically distributed over the study area (1 km x 1 km, n = 5,744 points) and photo-interpreted on the orthophotos. Confusion matrices were built comparing attributed classes for these points. S2-3D. The lowest difference in accuracy (0.4%) was for the PA of the forest class. y p S2 S2-3D OA (%) 91,7 92,6 PA forest (%) 91,9 92,3 UA forest (%) 94,5 95,5 PA non-forest (%) 91,3 93,0 UA non-forest (%) 87,5 88,2 Concerning Objective 2, 10% of the reference data extracted from DFU polygons was randomly selected to create a validation dataset. The number of observations by class was randomly downsampled to balance classes for the validation. Confusion matrices were built using these validation data. For Objectives 1 and 2, we computed the OA (overall accuracy) as well as producer (PA) and user accuracy (UA) for each class. S2-3D. The lowest difference in accuracy (0.4%) was for the PA of the forest class. Selected variables. The results presented in this section are based on the classifier trained with the S2-3D dataset, which obtained the best precisions. Figure 3 illustrates which S2 bands were mostly identified as relevant regarding our classification goals. A band was counted if it was selected at the VSurf interpretation step and each time it was used in a variable selected during the interpretation step. For Model 1, the three bands used the most were B8A, B11 and B12, all of which have a 20 m GSD. 3.2. Dataset preparation The process was executed with 2,000 trees to grow and mtry set by default. A series of parameters combinations were tested to find the most relevant parameters for this study. Before training the models, the number of observations by class was randomly downsampled to balance classes. Table 4. Accuracy comparison of the RF classifiers built with the S2 and S2-3D datasets for classification Objective 1. A visual interpretation of a systematic point grid (1 km x 1 km, n = 5,744 points) was used to compute accuracy indices: overall accuracy (OA), production accuracy (PA) and user accuracy (UA) by class — Comparaison des précisions atteintes résultant de l’utilisation des jeux de données S2 et S2-3D pour la classification Objectif 1. Une photointerprétation d’une grille de points systématique (1 km x 1 km, n = 5 744 points) a été utilisée pour calculer les indices de précision : overall accuracy (OA), production accuracy (PA) and user accuracy (UA) par classe. Table 4. Accuracy comparison of the RF classifiers built with the S2 and S2-3D datasets for classification Objective 1. A visual interpretation of a systematic point grid (1 km x 1 km, n = 5,744 points) was used to compute accuracy indices: overall accuracy (OA), production accuracy (PA) and user accuracy (UA) by class — Comparaison des précisions atteintes résultant de l’utilisation des jeux de données S2 et S2-3D pour la classification Objectif 1. Une photointerprétation d’une grille de points systématique (1 km x 1 km, n = 5 744 points) a été utilisée pour calculer les indices de précision : overall accuracy (OA), production accuracy (PA) and user accuracy (UA) par classe. 4.2. Objective 2: tree species classification Table 5. Percentage of selected S2 variables by spatial resolution and acquisition date of S2 image. The class “mixed” lists the variables computed with 10 m S2 bands and 20 m S2 bands — Pourcentage des variables S2 sélectionnées par résolution spatiale et par date d’acquisition de l’image S2. La classe « mixed » concerne les variables générées avec des bandes S2 à 10 m et des bandes S2 à 20 m. Table 5. Percentage of selected S2 variables by spatial resolution and acquisition date of S2 image. The class “mixed” lists the variables computed with 10 m S2 bands and 20 m S2 bands — Pourcentage des variables S2 sélectionnées par résolution spatiale et par date d’acquisition de l’image S2. La classe « mixed » concerne les variables générées avec des bandes S2 à 10 m et des bandes S2 à 20 m. Comparing the performance of both datasets. In order to compare the accuracies of achieved results for both the S2 and S2-3D dataset, user accuracies of all classes have been summarized by mean to make the comparison easier. For dataset S2, OA and the user accuracy mean (UA mean) were 88.5% and 88.6% while for dataset S2-3D, it was 88.9% and 89%. As with Model 1, the 3D dataset gave the best results but the differences in precision can be considered as negligible: in all cases the value was less than 0.5%. By date (%) By spatial resolution (%) 8/2/2015 5/8/2016 10 m mixed 20 m Objective 1 32.1 67.9 7.1 21.4 71.4 Objective 2 47.4 52.6 5.3 34.2 60.5 Selected variables. The results presented in this section concern the classifier trained with the S2-3D dataset that obtained the best precision values. They are summarized in figure 3 and table 5. The three most-selected bands at the VSurf interpretation step were B8A (NIR narrow), B5 (Red Edge 1), and B11 (SWIR 1), all of which have a 20 m GSD. Production of a forest map. The RF classifier generated with previous variables was used to compute a final forest map. This map was then filtered using the Majority Filter tool of ArcMap® (Number of neighbors to use: 8, Replacement threshold: MAJORITY). Figure 4 presents the result. A validation was carried out for the produced map. The OA value of the confusion matrix was 93.3%. 4.1. Objective 1: forest map Comparing the performance of both datasets. Table 4 shows the accuracy of the forest maps generated using the S2 and S2-3D datasets. These results were computed before post treatments and are presented to compare dataset performances. The presentation of the final forest map is described in Section 4.1.3. S2-3D gave the best results, with an overall accuracy difference of 0.9% between the two approaches. This difference is significant (p-value = 0.002421, McNemar’s chi-squared test realized on the contingency table of correctly classified and incorrectly classified points). The PA of the non-forest class had the highest difference in accuracy (1.7%) between S2 and In table 5, variables were sorted according to their sensing date and native spatial resolution. The term “mixed” means that S2 bands of both spatial resolutions were used to generate the index. Fourteen variables were selected during the VSurf prediction step. The list is presented in descending order of occurrence: CHM2, CHM3, B11-D2, CHM1, B7-D2, B12-D1, SLOPE, STI-D1, NDTI-D1, RTVIcore-D2, B5-D2, MSI-D2, NDrededgeSWIR-D1, and B5-D1. Bolyn C., Michez A., Gaucher P. et al. Biotechnol. Agron. Soc. Environ. 2018 22(3) 10 Figure 3. Frequency of selection for each S2 band (Table 1) by the VSurf selection process (Genuer et al., 2016) during the interpretation step. A band is counted if selected itself or inside a spectral indice variable — Fréquence de sélection de chaque bande S2 (Tableau 1) par le processus de sélection VSurf (Genuer et al., 2016) durant la phase d’interprétation. Une bande est comptabilisée si elle est sélectionnée elle-même ou au sein d’une variable d’indice spectral. Objective 1 Objective 2 Frequency Frequency 25 20 15 10 5 0 25 20 15 10 5 0 B2 B3 B4 B5 B6 B7 B8 B8a B11 B12 B2 B3 B4 B5 B6 B7 B8 B8a B11 B12 Objective 1 Objective 2 Figure 3. Frequency of selection for each S2 band (Table 1) by the VSurf selection process (Genuer et al., 2016) during the interpretation step. A band is counted if selected itself or inside a spectral indice variable — Fréquence de sélection de chaque bande S2 (Tableau 1) par le processus de sélection VSurf (Genuer et al., 2016) durant la phase d’interprétation. Une bande est comptabilisée si elle est sélectionnée elle-même ou au sein d’une variable d’indice spectral. 5.1. Variable selection It is interesting to observe the difference between Objectives 1 and 2 in figure 3. In Objective 1, the most selected bands were found, in order of number of appearances, B11, B8a, and B12. In Objective 2 the most selected bands were B8a, B5, and B11. These results are in line with the goals of classification models and band properties. Indeed, Objective 1 aimed at distinguishing forest classes (coniferous stands, broad-leaved stands, and recent clear-cuts) from non- forest areas. The second classification objective was separating tree species classes present on the study site. B11 is sensitive to forest above ground biomass and B12 facilitates distinction of live biomass, dead biomass, and soil (Table 2), thus B11 and B12 have Selected variables were well distributed between the two S2 images taken on different dates, especially for Objective 2. It appears that image interaction was useful. Choosing the time of image acquisition in relation to species’ phenological cycle is a possible way to improve discrimination. Immitzer et al. (2016) test a classification of tree species in Germany for seven classes on a single date. Their results show an OA of 0.64, an accuracy lower than what we found in this study, even for Dataset S2. This was probably Table 6. Confusion matrix of classification Objective 2 for Dataset S2-3D. The validation of Objective 2 was realized with 10% of the reference data. Classification Objective 2 concerned 11 classes: recent clear cuts (RCC), beech, birch, oak, other broad-leaved stands (OB), Douglas fir, larch, other needle-leaved stands (ON), Scots pine, spruce, young needle-leaved stands (YN). Producer accuracy (PA) and user accuracy (UA) are presented for each class — Matrice de confusion de la classification Objectif 2 pour le jeu de données S2-3D. La validation de la classification Objectif 2 a été réalisée en utilisant 10% des données de référence. La classification Objectif 2 concernait 11 classes : coupes récentes (RCC), hêtre (Beech), bouleau (Birch), chêne (Oak), autres peuplements feuillus (OB), douglas (Douglas fir), mélèze (Larch), autres peuplements résineux (ON), pin sylvestre (Scots pine), épicéa (Spruce), jeunes peuplements résineux (YN). La précision du producteur (PA) et la précision de l’utilisateur (UA) sont présentées pour chaque classe. 4.2. Objective 2: tree species classification Bolyn C., Michez A., Gaucher P. et al. Biotechnol. Agron. Soc. Environ. 2018 22(3) 12 Accuracy of the best classifier. Achieved accuracies with the S2-3D dataset are presented in detail by a confusion matrix (Table 6). The OA was 88.9%. The worse PA concerned the larch (79.9%) and recent clear cut (83.2%) classes. The worst UA were for beech (83.8%) and larch (86.3%). Accuracy of the best classifier. Achieved accuracies with the S2-3D dataset are presented in detail by a confusion matrix (Table 6). The OA was 88.9%. The worse PA concerned the larch (79.9%) and recent clear cut (83.2%) classes. The worst UA were for beech (83.8%) and larch (86.3%). more importance in Objective 1 where there are non-forest classes. B5 and B8a are more related to Objective 2; indeed, vegetation classification is the only goal in this case. Figure 3 shows the importance of shortwave infrared (SWIR) (B11 and B12) and the red-edge band B5 for both models, as mentioned in other studies (Schuster et al., 2012; Fassnacht et al., 2016; Immitzer et al., 2016; Radoux et al., 2016). 5. DISCUSSION Looking at table 5, we can see that the most selected variables have a GSD of 20 m. As a consequence, the resolution of the resulting maps was not really 10 m; even more without the use of 3D data. This confirms the relevance of spectral bands sensed by S2 but reminds us that spectral resolution can be more important than spatial resolution for vegetation discrimination at a regional scale. 4.2. Objective 2: tree species classification PA and UA were 93.2% and 95.8% for the forest class while it was 93.3% and 89.5% for the non-forest class. Eighteen variables were selected during VSurf prediction step. The list is presented in descending number of appearances: SLOPE, CHM1, CHM2, CHM3, RedSWIR1-D2, B8A-D2, B7-D2, B11-D2, NDrededgeSWIR-D1, B5D2, MSI-D2, NDWI1-D2, B12-D2, B6-D2, B11-D1, STI-D1, B5-D1, and LChloC-D1. 11 Forest mapping with Sentinel-2 imagery mapping with Sentinel 2 imagery 4°30’0’E 5°0’0’E 5°30’0’E 6°0’0’E 6°30’0’E 49°40’0’’N 50°0’0’’N 50°20’0’’N 50°40’0’’N N 0 5 10 20 30 40 km 0 0,5 1 2 km 6°0’0’E 6°30’0’E 4. On the top in RGB colour composition, one of the two S2 images (05/08/2015) used in this study. On th est map of the Belgian Ardenne ecoregion generated by merging the three forest classes of the classificat tive 1” into one. Both maps present a more detailed view in their top left corner — En haut en compositio une des deux images S2 (08/05/2015) utilisée dans cette étude. En bas, la carte forestière de l’écorégion de l générée en fusionnant les trois classes forestières du résultat de la classification « Objectif 1 » en une seule. présentent une vue plus détaillée dans leur coin supérieur gauche. 4°30’0’E 5°0’0’E 5°30’0’E 6°0’0’E 6°30’0’E 4°30’0’E 5°0’0’E 5°30’0’E 6°0’0’E 49°40’0’’N 50°0’0’’N 50°20’0’’N 50°40’0’’N 49°40’0’’N 50°0’0’’ 50°20’0’’N 50°40’0’’N N N 0 5 10 20 30 40 km 0 5 10 20 30 40 km Forest Non-forest 0 0,5 1 2 km 0 0,5 1 2 km 4°30’0’E 5°0’0’E 5°30’0’E 6°0’0’E 49°40’0’’N 50°0’0’’N 49°40’0’’N 50°0’0’’ 50°20’0’’N 50°40’0’’N N N 0 5 10 20 30 40 km 0 5 10 20 30 40 km Forest Non-forest 0 0,5 1 2 km 50°20’0’’N 50°0’0’’ Figure 4. On the top in RGB colour composition, one of the two S2 images (05/08/2015) used in this study. On the bottom, the forest map of the Belgian Ardenne ecoregion generated by merging the three forest classes of the classification result “Objective 1” into one. Both maps present a more detailed view in their top left corner — En haut en composition colorée RGB, l’une des deux images S2 (08/05/2015) utilisée dans cette étude. En bas, la carte forestière de l’écorégion de l’Ardenne belge, générée en fusionnant les trois classes forestières du résultat de la classification « Objectif 1 » en une seule. Les deux cartes présentent une vue plus détaillée dans leur coin supérieur gauche. Table 6. Confusion matrix of classification Objective 2 for Dataset S2-3D. The validation of Objective 2 was realized with 10% of the reference data. Classification Objective 2 concerned 11 classes: recent clear cuts (RCC), beech, birch, oak, other broad-leaved stands (OB), Douglas fir, larch, other needle-leaved stands (ON), Scots pine, spruce, young needle-leaved stands (YN). Producer accuracy (PA) and user accuracy (UA) are presented for each class — Matrice de confusion de la classification Objectif 2 pour le jeu de données S2-3D. La validation de la classification Objectif 2 a été réalisée en utilisant 10% des données de référence. La classification Objectif 2 concernait 11 classes : coupes récentes (RCC), hêtre (Beech), bouleau (Birch), chêne (Oak), autres peuplements feuillus (OB), douglas (Douglas fir), mélèze (Larch), autres peuplements résineux (ON), pin sylvestre (Scots pine), épicéa (Spruce), jeunes peuplements résineux (YN). La précision du producteur (PA) et la précision de l’utilisateur (UA) sont présentées pour chaque classe. 5.1. Variable selection Prediction Reference RCC Beech Birch Oak OB Douglas fir Larch ON Scots pine Spruce YN UA (%) RCC 223 2 3 1 2 1 3 1 1 0 4 92.5 Beech 5 238 1 1 8 3 6 11 3 4 4 83.8 Birch 8 5 259 4 2 3 3 3 0 3 1 89.0 Oak 1 1 1 229 2 5 8 0 2 1 1 91.2 OB 6 0 1 5 242 3 4 2 3 2 1 90.0 Douglas fir 2 2 0 3 4 232 16 3 1 1 2 87.2 Larch 8 6 0 1 2 4 214 8 4 0 1 86.3 ON 2 7 0 2 1 7 5 236 0 1 1 90.1 Scots pine 3 2 2 4 2 0 0 0 249 4 2 92.9 Spruce 6 2 0 9 2 7 4 1 4 251 3 86.9 YN 4 3 1 9 1 3 5 3 1 1 248 88.9 PA (%) 83.2 88.8 96.6 85.4 90.3 86.6 79.9 88.1 92.9 93.7 92.5 Forest mapping with Sentinel-2 imagery 13 ecoregion. The RFI only considers forest elements bigger than 0.1 ha and wider than 20 m. This limit could partly explain the over-estimation; pixel groups smaller than 10 pixels, correctly classified or not, are common on the forest map. partially because of our use of images taken on two dates. It would be interesting to test the use of images taken on several dates during the vegetation period in order to benefit from tree species phenology. Particularly for broad-leaved species, a series of dates from March to May should help to detect differences in foliation period. This is a task for future study; the growing availability of free data from S2 satellites makes this research a possibility. i The results of second objective, concerning tree species discrimination, were encouraging (Table 6). The obtained precisions were better than those in previous studies using S2 data (Immitzer et al., 2016) and similar or better than those in studies using data from other sensors with various spatial and spectral resolution (Immitzer et al., 2012). For this number of classes and this study area size, these results are encouraging. This approach demonstrates the possibility of efficiently mapping regional tree species with S2 imagery in the future. Nevertheless, the study did have some limitations, due to its workflow and the reference data used. 5.1. Variable selection During the final VSurf prediction step, all 3D data were taken into account and were among the best variables for both objectives. The slope was the best for Ojective 2, showing that the presence of certain species in the study site is strongly related to the topography. Fourteen variables were selected for Objective 1 and 18 for Objective 2. Except NDTI and RTVIcore, all the variables in Objective 1 were included in Objective 2. In addition, Objective 2 included additional indices and S2 bands, which helped to discriminate vegetation species. As expected, this suggests that more information is needed to solve a complex problem like separating tree species. Just as the SWIR and red-edge bands were the most selected S2 variable during the VSurf interpretation step, almost all the variables selected during the VSurf prediction step were a SWIR or red- edge band or a spectral index computed with at least one of these bands. First, because of the availability of data the number of different forest stands for some species used to extract pixels was limited (from 31 to 64, Table 3). This means that the within-species variance of training data sets was probably too reduced for a large area like the Belgian Ardenne. Furthermore, the DFU cover only public forests that represent 57% of the study area. It will be important for future studies to represent as best as possible the variability of species. Further research could also eventually consider ecological gradients in analyses (e.g. water proximity, elevation, sunlight exposure). For instance, the benefit of using ancillary geodata in a classification process has been studied in Forster & Kleinschmit (2014). 5.3. Contribution of 3D data compared. The precision of produced forest maps was evaluated with a visually interpreted systematic point grid at intervals of 1,000 m. For the second model, the models were validated with 10% of the reference data. In the creation of the forest map, the use of 3D data significantly improved the precision. However, it appears that at a large scale and at this spatial resolution it is possible to get sufficient predictions using only S2 imagery. The best improvements using 3D data were seen in the UA of the forest class and in consequence for the PA of the non-forest class. Information about tree height should, most of the time, limit confusion between other vegetation and forest; the observed trend confirmed this idea. Furthermore, including old clear cuts in the forest map is a complicate task without using anterior CHM’s. Taking into account the fact that most of the variables used in the classification have a 20 m GSD, the 10 m spatial resolution of the 3 CHM is probably an advantage for the classification of edges. It could improve the precision at those locations where 20 m pixels have more chance to overlap the edge between forest and non-forest classes. So the quality of geometric limits is probably better for the forest map realized with the S2-3D dataset. The evidence from this study suggests that this approach enables accurate classification without 3D data. For Objective 1, classification realized with 3D data was significantly better, with an OA difference of 0.9%. For Objective 2, the improvement in OA was negligible (0.4%). The produced forest map had an OA of 93.3%. The test of tree species discrimination was conclusive and encouraging with an OA of 88.9%. Concerning Objective 2, it is important to remember that the present study has investigated a simplified per-pixel classification with pixels extracted from a limited number of pure stands. As a consequence of these simplifications, the precision evaluated was probably over-estimated for the application of the classifier on the whole study site. Despite these limitations, the results confirmed the great potential of S2 imagery for tree species discrimination. More specifically, the SWIR and red-edge S2 bands are essential, as they were by far the most important in our variable selection process. Their spatial resolution of 20 m can lead to restrictions for detailed analyses. 5.2. Precision of the results Bolyn C., Michez A., Gaucher P. et al. Biotechnol. Agron. Soc. Environ. 2018 22(3) 14 5.3. Contribution of 3D data That is why we recommend that further research combines S2 imagery with another data source at very high spatial resolution in order to exploit the undeniable discrimination power of S2 and a better spatial precision. Along the same lines, we achieved similar results both using a 3D dataset and without, but precisions of edges and the detection of small elements seemed to be improved using 3D data. That improvement has not been evaluated in this study. The main gain of using 3D data was the improvement of the forest map and the clear cuts detection. In further research, it would be interesting to generate a forest map including clear cuts, starting from 3D data only at a higher spatial resolution. In Objective 2, the global improvement brought by 3D data was less important than in Objective 1. In average, precision did not increase by more than 0.5%. The only interesting exception is the PA of the RCC class, which increased by 5%. As expected, the 3 CHM improved the detection of recent clear cuts. Surprisingly, the detection of YN class did not improve. It appears that their S2 information is already distinguishable from that of other classes without information about height. The use of CHM is not very relevant for the discrimination of tree species at this spatial resolution. In contrast, a derived variable of environment, like the slope (selected as first variable at VSurf prediction step), seems to bring more interesting information and improving such an approach could be pertinent. The choice of an object-based approach and the use of better acquisition dates are possible methods to improve our classification results. To further our research, we plan to work on the quality of reference data and to develop adequate methods to surpass the test step and create tree species classifiers operational for the production of tree species maps at large scale with an assessment of their precision in the best way. 6. CONCLUSIONS This paper investigates the new opportunity offered by Sentinel-2 imagery to classify forest and forest species at large scale. Two cloud-free S2 scenes (02/08/2015 and 08/05/2016) were used and a series of spectral indices were computed for each. After variable selection, we applied supervised pixel-based classifications with a random forest classifier. A first model of classification aimed at creating a forest map of the Belgian Ardenne ecoregion. A second tested tree species discrimination for species present on the study site. These two models of classification were processed with both a pure S2 dataset and with additional 3D data and the obtained precisions were 5.2. Precision of the results The produced forest map (Objective 1) had a very good precision rate, with an OA of 93.3%. In our reference dataset, used for classifier construction, the non-forest class was composed of different land cover and was less homogeneous than other classes. The non-forest class UA was worse than for the forest class, probably for this reason. In this study, we did not control the behavior of the classifier with small woodland areas like isolated trees or bands of trees. The precision of the map could be negatively impacted by fragmented landscape elements because the spatial resolution of S2 is probably too low for this purpose, and edge pixels represent a large proportion of the total, increasing the bias due to sub-pixel variations (not evaluated here) (Stratoulias et al., 2015; Immitzer et al., 2016; Radoux et al., 2016). Hence, a possible improvement for users of this map could be to choose an appropriate definition for the forest that would remove these problematic elements. According to the Walloon Forest Inventory (Alderweireld et al., 2015), the Belgian Ardenne ecoregion includes 333,850 ha of forest area. Based on the forest map classification and the confusion matrix, an area estimator of forest was computed (Olofsson et al., 2013) at 354,761.3 ha (± 3,695.57 ha) of forest in the Belgian Ardenne Second, we did not manage to account for species mixing at the pixel level. Indeed, the probability to have a single tree or stand exactly covered by a single pixel matching its extent is low (Fassnacht et al., 2016). The simplification done when extracting pixels from supposedly pure stands resulted in interesting conclusions regarding the separate nature of species. But it is not yet sufficient to create a map of species distribution, since the study area includes many mixed pixels. Furthermore, for this study, the most important S2 bands were sensed at 20 m GSD, increasing these effects. As a consequence of these two simplifications, the precision evaluated by independent validation was probably over-estimated for the application of the classifier over the whole study site. Choosing an object-based approach and processing segmentation with very high resolution images like orthophotos would allow researchers to work at the scale of one stand or tree group (Kumar, 2006). It could partly solve these issues and would give researchers the interesting opportunity to combine advantages from a time series of S2 images and very high-resolution images. Bibliography Agapiou A. et al., 2011. The importance of accounting for atmospheric effects in the application of NDVI and interpretation of satellite imagery supporting archaeological research: the case studies of Palaepaphos and Nea Paphos sites in Cyprus. Remote Sens., 3(12), 2605-2629. Genuer R., Poggi J.-M. & Tuleau-Malot C., 2015. VSURF: An R package for variable selection using random forests. R Journal, 7(2), 19-33. Genuer R., Poggi J.-M. & Tuleau-Malot C., 2016. VSURF: variable selection using random forests. R package version 1.0.3. Gitelson A.A., Kaufman Y.J. & Merzlyak M.N., 1996. Use of a green channel in remote sensing of global vegetation from EOS-MODIS. Remote Sens. Environ., 58(3), 289- 298. Alderweireld M., Burnay F., Pitchugin M. & Lecomte H., 2015. Inventaire forestier wallon. Résultats 1994-2012. Namur, Belgique : Service Public de Wallonie. Blackburn G.A., 1998. Quantifying chlorophylls and caroteniods at leaf and canopy scales: an evaluation of some hyperspectral approaches. Remote Sens. Environ., 66(3), 273-285. Guanter L., Gomez-Chova L. & Moreno J., 2008. Coupled retrieval of aerosol optical thickness, columnar water vapor and surface reflectance maps from ENVISAT/ MERIS data over land. Remote Sens. Environ., 112(6), 2898-2913. Breiman L., 2001. Random forests. Mach. Learn., 45(1), 5-32. Hagolle O., Huc M., Pascual D. & Dedieu G., 2015. A multi-temporal and multi-spectral method to estimate aerosol optical thickness over land, for the atmospheric correction of FormoSat-2, LandSat, VENS and Sentinel-2 Images. Remote Sens., 7(3), 2668-2691. Chen P.-F. et al., 2010. New index for crop canopy fresh biomass estimation. Spectrosc. Spectral Anal., 30(2), 512-517. Datt B., 1999. Visible/near infrared reflectance and chlorophyll content in Eucalyptus leaves. Int. J. Remote Sens., 20(14), 2741-2759. Huete A.R., 1988. A soil-adjusted vegetation index (SAVI). Remote Sens. Environ., 25(3), 295-309. Domenech E. & Mallet C., 2014. Change detection in high- resolution land use/land cover geodatabases (at object level). EuroSDR, 64. Immitzer M., Atzberger C. & Koukal T., 2012. Tree species classification with random forest using very high spatial resolution 8-band worldview-2 satellite data. Remote Sens., 4(9), 2661-2693. European Commission, 2015. Copernicus: Europe’s Eyes on Earth. Luxembourg: Publications Office. Immitzer M., Vuolo F. & Atzberger C., 2016. First experience with sentinel-2 data for crop and tree species classifications in central Europe. Remote Sens., 8(3), 166. European Space Agency, 2015. Sentinel-2a MSI Spectral Responses.xlsx, https://earth.esa.int/web/sentinel/ document-library/latest-documents/-/asset_publisher/ EgUy8pfXboLO/content/sentinel-2a-spectral-respo nses;jsessionid=AA5AEEAE5B3515EFB534D44F 239D5FD1.jvm2?redirect=https%3A%2F%2Fearth. esa.int%2Fweb%2Fsentinel%2Fdocument- library%2Flatest-documents%3Bjsessionid%3DAA5A EEAE5B3515EFB534D44F239D5FD1.jvm2%3Fp_p_ id%3D101_INSTANCE_EgUy8pfXboLO%26p_p_ lifecycle%3D0%26p_p_state%3Dnormal%26p_p_ mode%3Dview%26p_p_col_id%3Dcolumn-1%26p_p_ col_pos%3D1%26p_p_col_count%3D2, (18/12/2017). Inglada J. et al., 2017. Forest mapping with Sentinel-2 imagery and hydric status. Int. J. Remote Sens., 15(7), 1459- 1470. Funding This research received financial support from the European Project Interreg V - Forêt Pro Bos portefeuille FeelWood and from the Directorate of Forest Resources (Department of Nature and Forests, General Operational Directorate for Agriculture, Natural Resources and Environment, Public Service of Wallonia) through the Accord-cadre de Recherche et de Vulgarisation Forestière. Forster M. & Kleinschmit B., 2014. Significance analysis of different types of ancillary geodata utilized in a multisource classification process for forest identification in Germany. IEEE Trans. Geosci. Remote Sens., 52(6), 3453-3463. Führer E., 2000. Forest functions, ecosystem stability and management. For. Ecol. Manage., 132(1), 29-38. Gao B.-C., 1996. NDWI. A normalized difference water index for remote sensing of vegetation liquid water from space. Remote Sens. Environ., 58(3), 257-266. Acknowledgements The authors would like to acknowledge the Department of Nature and Forests (General Operational Directorate for Agriculture, Natural Resources and Environment, Public Service of Wallonia) for providing their geodatabase. 15 Bibliography Operational high resolution land cover map production at the country scale using satellite image time series. Remote Sens., 9(1), 95. Jacques D.C. et al., 2014. Monitoring dry vegetation masses in semi-arid areas with MODIS SWIR bands. Remote Sens. Environ., 153, 40-49. Jensen J.R., 2005. Introductory digital image processing: a remote sensing perspective. Upper Saddle River, NJ, USA: Prentice Hall. Kaufman Y. et al., 1997. Passive remote sensing of tropospheric aerosol and atmospheric correction for the aerosol effect. J. Geophys. Res., 102(D14), 16815-16830. Fassnacht F.E. et al., 2016. Review of studies on tree species classification from remotely sensed data. Remote Sens. Environ., 186, 64-87. Kumar N., 2006. Multispectral image analysis using the object-oriented paradigm. Boca Raton, FL, USA: CRC Press. Filella I. & Penuelas J., 1994. The red edge position and shape as indicators of plant chlorophyll content, biomass Biotechnol. Agron. Soc. Environ. 2018 22(3) Bolyn C., Michez A., Gaucher P. et al. 16 Schuster C., Förster M. & Kleinschmit B., 2012. Testing the red edge channel for improving land-use classifications based on high-resolution multi-spectral satellite data. Int. J. Remote Sens., 33(17), 5583-5599. Lacaux J. et al., 2007. Classification of ponds from high- spatial resolution remote sensing: application to Rift Valley fever epidemics in Senegal. Remote Sens. Environ., 106(1), 66-74. Le Maire G., François C. & Dufrêne E., 2004. Towards universal broad leaf chlorophyll indices using PROSPECT simulated database and hyperspectral reflectance measurements. Remote Sens. Environ., 89(1), 1-28. Shahi K. et al., 2015. A novel spectral index to automatically extract road networks from WorldView-2 satellite imagery. Egypt. J. Remote Sens. Space Sci., 18(1), 27-33. Song C. et al., 2001. Classification and change detection using Landsat TM data: when and how to correct atmospheric effects? Remote Sens. Environ., 75(2), 230- 244. Liaw A. & Wiener M., 2002. Classification and regression by randomForest. R News, 2(3), 18-22. Lichtenthaler H.K. et al., 1996. Detection of vegetation stress via a new high resolution fluorescence imaging system. J. Plant Physiol., 148(5), 599-612. Sripada R.P., Heiniger R.W., White J.G. & Meijer A.D., 2006. Aerial color infrared photography for determining early in-season nitrogen requirements in corn. Agron. J., 98(4), 968. Lillesand T.M., Kiefer R.W. & Chipman J.W., 2008. Remote sensing and image interpretation. Hoboken, NJ, USA: John Wiley & Sons. Stratoulias D. et al., 2015. Evaluating Sentinel-2 for lakeshore habitat mapping based on airborne hyperspectral data. Sensors, 15(9), 22956-22969. Lindenmayer D.B., Margules C.R. & Botkin D.B., 2000. Bibliography Indicators of biodiversity for ecologically sustainable forest management. Conserv. Biol., 14(4), 941-950. Suhet & Hoersch B., 2015. Sentinel-2 user handbook. European Space Agency. Tomppo E., Gschwantner T., Lawrence M. & McRoberts R.E., eds, 2010. National forest inventories. Dordrecht, The Netherlands: Springer Netherlands. McDermid G. et al., 2009. Remote sensing and forest inventory for wildlife habitat assessment. For. Ecol. Manage., 257(11), 2262-2269. McRoberts R. & Tomppo E., 2007. Remote sensing support for national forest inventories. Remote Sens. Environ., 110(4), 412-419. Tucker C.J., 1979. Red and photographic infrared linear combinations for monitoring vegetation. Remote Sens. Environ., 8(2), 127-150. Michez A., Piégay H., Lejeune P. & Claessens H., 2017. Multi-temporal monitoring of a regional riparian buffer network (> 12,000 km) with LiDAR and photogrammetric point clouds. J. Environ. Manage., 202(2), 424-436. Van Deventer A.P., Ward A.D., Gowda P.H. & Lyon J.G., 1997. Using thematic mapper data to identify contrasting soil plains and tillage practices. Photogramm. Eng. Remote Sens., 63, 87-93. Vogelmann J.E. & Rock B.N., 1985. Spectral characterization of suspected acid deposition damage in red spruce (Picea Rubens) stands from Vermont. In: Proceedings of the Airborne Imaging Spectrometer Data Analysis Workshop, April 8-10, 1985, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, United States, 51-55. Müller-Wilm U., 2016. Sentinel-2 MSI. Level-2a prototype processor installation and user manual. Darmstadt, Germany: Telespazio Vega. Olofsson P., Foody G.M., Stehman S.V. & Woodcock C.E., 2013. Making better use of accuracy data in land change studies: estimating accuracy and area and quantifying uncertainty using stratified estimation. Remote Sens. Environ., 129, 122-131. Waser L. et al., 2011. Semi-automatic classification of tree species in different forest ecosystems by spectral and geometric variables derived from Airborne Digital Sensor (ADS40) and RC30 data. Remote Sens. Environ., 115(1), 76-85. Pinty B. & Verstraete M.M., 1992. GEMI: a non-linear index to monitor global vegetation from satellites. Vegetatio, 101(1), 15-20. Wulf H. & Stuhler S., 2015. Sentinel-2: land cover, preliminary user feedback on Sentinel-2a data. In: Proceedings of the Sentinel-2a expert users technical meeting, 29-30 September 2015, Frascati, Italy. R Core Team, 2016. R: a language and environment for statistical computing. Vienna: R Foundation for Statistical Computing. Radoux J. et al., 2016. Sentinel-2’s potential for sub-pixel landscape feature detection. Remote Sens., 8(6), 488. Richards J.A., 2013. Remote sensing digital image analysis. Berlin; Heidelberg, Germany: Springer. (54 ref.)
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Fermentable Oligo-, Di-, and Mono-Saccharides and Polyols (FODMAPs) Consumption and Irritable Bowel Syndrome in the French NutriNet-Santé Cohort
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Fermentable Oligo-, Di-, and Mono-Saccharides and Polyols (FODMAPs) Consumption and Irritable Bowel Syndrome in the French NutriNet-Santé Cohort Elodie Schneider, Jean-Marc Sabaté, Michel Bouchoucha, Serge Hercberg, Mathilde Touvier, Robert Benamouzig, Chantal Julia, Camille Buscail To cite this version: Elodie Schneider, Jean-Marc Sabaté, Michel Bouchoucha, Serge Hercberg, Mathilde Touvier, et al.. Fermentable Oligo-, Di-, and Mono-Saccharides and Polyols (FODMAPs) Consumption and Irri- table Bowel Syndrome in the French NutriNet-Santé Cohort. Nutrients, 2021, 13 (12), pp.4513. ￿10.3390/nu13124513￿. ￿hal-03623131￿ Distributed under a Creative Commons Attribution 4.0 International License Fermentable Oligo-, Di-, and Mono-Saccharides and Polyols (FODMAPs) Consumption and Irritable Bowel Syndrome in the French NutriNet-Santé Cohort er 1,* , Jean-Marc Sabaté 2,3, Michel Bouchoucha 2 , Serge Hercberg 1,4, Mathilde Touvier 1 uzig 2, Chantal Julia 1,4 and Camille Buscail 1,4 Elodie Schneider 1,* , Jean-Marc Sabaté 2,3, Michel Bouchoucha 2 , Serge Hercberg 1,4, Ma Robert Benamouzig 2, Chantal Julia 1,4 and Camille Buscail 1,4 Elodie Schneider 1,* , Jean-Marc Sabaté 2,3, Michel Bouchoucha 2 , Serge Hercberg 1,4, Mathilde Touvier 1 , Robert Benamouzig 2, Chantal Julia 1,4 and Camille Buscail 1,4 1 Nutritional Epidemiology Research Team (EREN), Sorbonne Paris Cité Epidemiology and Statistics Research Center (CRESS), Inserm U1153, Inrae U1125, Cnam, Université Sorbonne Paris Nord University, 93017 Bobigny, France; s.hercberg@eren.smbh.univ-paris13.fr (S.H.); m.touvier@eren.smbh.univ-paris13.fr (M.T.); c.julia@eren.smbh.univ-paris13.fr (C.J.); cdebrauer@institutcancer.fr (C.B.) 2 Service de Gastroentérologie, Hôpital Avicenne, APHP, 93017 Bobigny, France; jean-marc.sabate@aphp.fr (J.-M.S.); michel.bouchoucha@aphp.fr (M.B.); robert.benamouzig@aphp.fr (R.B.) 3 INSERM U-987, Hôpital Ambroise Paré (APHP), 92104 Boulogne-Billancourt, France 4 Département de Santé Publique, Hôpital Avicenne (APHP), 93017 Bobigny, France * Correspondence: e.schneider@eren.smbh.univ-paris13.fr 2 Service de Gastroentérologie, Hôpital Avicenne, APHP, 93017 Bobigny, France; jean-marc.sabate@aphp.fr (J.-M.S.); michel.bouchoucha@aphp.fr (M.B.); robert.benamouzig@aphp.fr (R.B.) 3 INSERM U-987, Hôpital Ambroise Paré (APHP), 92104 Boulogne-Billancourt, France 4 Département de Santé Publique, Hôpital Avicenne (APHP), 93017 Bobigny, France * Correspondence: e.schneider@eren.smbh.univ-paris13.fr 3 INSERM U-987, Hôpital Ambroise Paré (APHP), 92104 Boulogne-Billancourt, France 4 Département de Santé Publique, Hôpital Avicenne (APHP), 93017 Bobigny, France * C d h id @ bh i i 13 f Département de Santé Publique, Hôpital Avicenne (APHP), 93017 Bobigny, France * Correspondence: e.schneider@eren.smbh.univ-paris13.fr p q , p ( ), g y, * Correspondence: e.schneider@eren.smbh.univ-paris13.fr Abstract: (1) Background: Specific foods, and more particularly, fermentable oligo-, di-, and mono- saccharides and polyols (FODMAPs) are often considered as triggers of digestive symptoms in Irritable Bowel Syndrome (IBS). Our aim was to study FODMAP consumption in controls and IBS participants in a large French population-based cohort; (2) Methods: Participants from the NutriNet- Santé cohort study completed the Rome IV and IBS-SSS questionnaire in a cross sectional study. Among them, 27,949 eligible participants had previously completed three 24-h recalls as well as anthropometrics, socio-demographical and lifestyle data. Total FODMAP intake (in g/day) was computed using a specific composition table. The association between FODMAPs and IBS was estimated through multivariable logistic regression models; (3) Results: Included participants were mainly women (75.4%) and the mean age was 43.4 ± 14.1 years. FODMAPs accounted for a mean daily intake of 19.4 ± 9.5 g/day.   Citation: Schneider, E.; Sabaté, J.-M.; Bouchoucha, M.; Hercberg, S.; Touvier, M.; Benamouzig, R.; Julia, C.; Buscail, C. Fermentable Oligo-, Di-, and Mono-Saccharides and Polyols (FODMAPs) Consumption and Irritable Bowel Syndrome in the French NutriNet-Santé Cohort. Nutrients 2021, 13, 4513. https:// doi.org/10.3390/nu13124513 Academic Editor: Toshifumi Ohkusa Keywords: IBS; FODMAP intake; cross-sectional study; Rome IV criteria; Nutrinet-Santé cohort study Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Fermentable Oligo-, Di-, and Mono-Saccharides and Polyols (FODMAPs) Consumption and Irritable Bowel Syndrome in the French NutriNet-Santé Cohort Overall 1295 participants (4.6%) were identified with an IBS. After adjusting for confounding factors, IBS participants had lower intakes in FODMAPs than non-IBS ones (aOR: 0.88, 95% CI: 0.82–0.95, p-value: 0.001). IBS severity was associated with more frequent low FODMAP intakes (<9 g/day); (4) Conclusions: Participants tended to consume 19 g of FODMAPs per day, but slightly less for IBS participants than for controls. In IBS participants, higher severity was associated with lower intakes.   Citation: Schneider, E.; Sabaté, J.-M.; Bouchoucha, M.; Hercberg, S.; Touvier, M.; Benamouzig, R.; Julia, C.; Buscail, C. Fermentable Oligo-, Di-, and Mono-Saccharides and Polyols (FODMAPs) Consumption and Irritable Bowel Syndrome in the French NutriNet-Santé Cohort. Nutrients 2021, 13, 4513. https:// doi.org/10.3390/nu13124513 Academic Editor: Toshifumi Ohkusa Received: 15 November 2021 Accepted: 13 December 2021 Published: 17 December 2021   Citation: Schneider, E.; Sabaté, J.-M.; Bouchoucha, M.; Hercberg, S.; Touvier, M.; Benamouzig, R.; Julia, C.; Buscail, C. Fermentable Oligo-, Di-, and Mono-Saccharides and Polyols (FODMAPs) Consumption and Irritable Bowel Syndrome in the French NutriNet-Santé Cohort. Nutrients 2021, 13, 4513. https:// doi.org/10.3390/nu13124513 Academic Editor: Toshifumi Ohkusa Received: 15 November 2021 Accepted: 13 December 2021 Published: 17 December 2021 Keywords: IBS; FODMAP intake; cross-sectional study; Rome IV criteria; Nutrinet-Santé cohort study HAL Id: hal-03623131 https://cnam.hal.science/hal-03623131v1 Submitted on 29 Mar 2022 L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. Distributed under a Creative Commons Attribution 4.0 International License nutrients nutrients nutrients   Citation: Schneider, E.; Sabaté, J.-M.; Bouchoucha, M.; Hercberg, S.; Touvier, M.; Benamouzig, R.; Julia, C.; Buscail, C. Fermentable Oligo-, Di-, and Mono-Saccharides and Polyols (FODMAPs) Consumption and Irritable Bowel Syndrome in the French NutriNet-Santé Cohort. Nutrients 2021, 13, 4513. https:// doi.org/10.3390/nu13124513 Academic Editor: Toshifumi Ohkusa Received: 15 November 2021 Accepted: 13 December 2021 Published: 17 December 2021 2.2. Ethics This study was conducted in accordance with the Declaration of Helsinki, and was approved by the Institutional Review Board of the French Institute for Health and Med- ical Research (IRB Inserm 0000388FWA00005831) and the “Commission Nationale de l’Informatique et des Libertés” (CNIL n 908450 and 909216). The study is registered at clinicaltrials.gov (accessed on 21 May 2019) as NCT03335644. All participants provided an electronic informed consent. 2.3. Data Collection 2.3.1. Irritable Bowel Syndrome 2.3.1. Irritable Bowel Syndrome An additional questionnaire was sent to the cohort in April 2018 to assess gastroin- testinal disorders. History of digestive diseases and symptoms were collected using the Rome IV questionnaire to define IBS (with symptoms for at least 6 months) [26]. The ques- tionnaire also included several questions about digestive medical history and symptoms. Thus, people were not eligible to participate in this study if they had had a history of rectal bleeding, melena, hematemesis, or significant unintentional weight loss (>5 kg) in the past 3 months, as well as a history of oesophagus, stomach or colorectal cancer, coeliac disease or ulcerative colitis in their family, as these symptoms were considered proxies for an organic underlying condition. 2.1. Population The NutriNet-Santé study is a web-based prospective observational cohort study that includes French adults from the general population (more than 160,000 recruited to date). Detailed description of the cohort is available elsewhere [25]. Briefly, it aims at studying the relations between nutrition and health, as well as determinants of dietary patterns and nutritional status [25]. Inclusions started in May 2009 and were still ongoing at the time of this study. At baseline, participants completed a set of five questionnaires about socio-demographic and lifestyle characteristics, anthropometry, health status, physical activity and diet. These questionnaires were repeated yearly. Furthermore, during follow- up, additional questionnaires on other specific topics dealing with determinants of food behaviors or health were regularly sent to participants. 1. Introduction Fermentable oligo-, di-, and mono-saccharides and polyols (FODMAPs) are short chain carbohydrates that are poorly absorbed in the gastrointestinal tract [1]. They include fructose in excess of glucose, lactose, fructans, galacto-oligo-saccharides (GOS) and polyols. They are ubiquitous in our diet, in particular through fruits, vegetables, legumes, dairy products, cereal products, oilseeds, seasonings, sugary products, alcoholic beverages, sugar-free products or sweeteners, and many processed items [2–5]. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). g p y p Among functional gastrointestinal disorders (FGIDs), irritable bowel syndrome (IBS) is one of the most prevalent and has therefore been of interest in recent years, affecting about 6–11% of the general population depending on the diagnostic criteria [6–8]. On this point, the Rome foundation recently updated the criteria used to diagnose IBS with the Rome IV criteria [9,10]. IBS, which is defined by chronic abdominal pain associated with a change https://www.mdpi.com/journal/nutrients Nutrients 2021, 13, 4513. https://doi.org/10.3390/nu13124513 Nutrients 2021, 13, 4513 2 of 13 in bowel habits, can be responsible for an impairment in quality of life of patients with severe disease and for an economic burden [11,12]. While IBS pathophysiology remains unclear, nutrient and non-nutrient components of foods, including FODMAPs, are often suspected to trigger IBS symptoms such as abdominal pain, bloating, excessive passage of gas and also diarrhea [13–16]. In recent years, several clinical trials have suggested that a low FODMAP diet (LFD) may be associated with a reduction in IBS symptoms [5,17–21]. ( ) y y p Reviews on this association expressed a lack of large-scale data [22–24]. Moreover, comparisons between FODMAP consumption in IBS participants and control subjects are lacking; only Halmos et al. described similar levels of daily intakes in a study with 30 IBS patients and 8 healthy subjects [5]. p y j The main aim of this work was to study FODMAP consumption in both IBS partici- pants and in controls and to assess the relationships between FODMAP load, IBS symptoms and severity in a large national cohort (NutriNet-Santé). 2.3.2. Diet Participants were requested to fill a set of three 24-h diet recall interviews at base- line and every 6 months (three non-consecutive days over a fortnight including two on weekdays and one during a weekend) [25]. Food record relied on a meal-based approach, asking nature and sizes of the portions of food eaten at each occasion (including meals and snacking periods). Portion sizes were assessed using validated photographs [27], and dietary intakes were based on the NutriNet-Santé food composition table [28]. This Nutrients 2021, 13, 4513 3 of 13 3 of 13 self-administered food record method has been validated in several studies in comparison to urinary biomarkers and interview by a dietitian [29–31]. In this work, the first full set of food records available was used to estimate dietary intakes for each individual. A specific composition table was used to assess FODMAP consumption [32]. This table enables to compute total FODMAP intake (in weight, grams/day), as well as each of: fructose in excess of glucose (excess-fructose), lactose, fructans, GOS and polyols for each participant. For the analyses, total FODMAP intakes were divided into three categories (<9 g/day, 9–16 g/day, ≥16 g/day) according to previous works published on low and usual FODMAP diet [5,33,34]. Eligible participants for this study had completed at least one full set of three 24-h food records after the inclusion and prior to the Rome IV questionnaire. Under-reporters of energy intake, identified through the Black method, were excluded from this study [35]. 2.3.3. IBS Scoring System The IBS Symptom Scoring System (IBS-SSS) was used to assess IBS severity in partici- pants with IBS diagnosis based on the Rome IV questionnaire. Other participants were also asked to fill this scoring system if they were previously diagnosed with an IBS or if they suspected they suffered from IBS (based on self-report). The IBS-SSS is divided into 5 main items (abdominal pain severity and frequency, abdominal distension severity, bowel habit satisfaction and impact on quality of life), ranged 1–100 each. The maximal achievable score is 500, mild, moderate and severe cases are indicated by scores of 75 to 175, 175 to 300 and >300 respectively. This score has been validated and described in detail elsewhere [36]. 2.3.4. Covariates Information on socio-demographic characteristics was collected at baseline: age, sex, marital status (single/living with someone), smoking status (current smoker/former smoker/non-smoker), monthly income and composition of the household enabling to calculate monthly income per consumption unit (c.u.) (unwilling to answer/<1110 € per c.u./1110–2330 € per c.u./>2330 € per c.u.) [37], educational level (no diploma or primary school/secondary school/undergraduate school/graduate school) and residence (rural area/urban area). Self-reported weight and height at baseline were used to calculate body mass index (BMI, in kg/m2) (<18.5/18.5–25/25–30/≥30) [38–40]. A specific questionnaire was administered at baseline to assess physical activity level using the International Physi- cal Activity Questionnaire (IPAQ, Intense/Moderate/Low) [41]. Total energy intake was computed (in kcal/day). 3.1. Population 3.1. Population Th fi l The final sample included 27,949 people (Figure 1). Participants were mostly women (75.4%) with a mean age of 47.8 ± 14.1 years. Overall description of the population and comparison between non-IBS participants and IBS subjects using the Rome IV questionnaire is shown in Table 1. The final sample included 27,949 people (Figure 1). Participants were mostly women (75.4%) with a mean age of 47.8 ± 14.1 years. Overall description of the population and comparison between non-IBS participants and IBS subjects using the Rome IV question- naire is shown in Table 1. Figure 1. Flowchart of the IBS-SSS study, NutriNet-Santé cohort, France, 2009–2019 (N = 27,949). Figure 1. Flowchart of the IBS-SSS study, NutriNet-Santé cohort, France, 2009–2019 (N = 27,949). Figure 1. Flowchart of the IBS-SSS study, NutriNet-Santé cohort, France, 2009–2019 (N = 27,949). Figure 1. Flowchart of the IBS-SSS study, NutriNet-Santé cohort, France, 2009–2019 (N = 27,949). Figure 1. Flowchart of the IBS-SSS study, NutriNet-Santé cohort, France, 2009–2019 (N = 27,94 Figure 1. Flowchart of the IBS-SSS study, NutriNet-Santé cohort, France, 2009–2019 (N = 27,949) ics of participants according to IBS status, NutriNet-Santé cohort, France, 2009–2019 (N = 27,949). cs of participants according to IBS status, NutriNet-Santé cohort, France, 2009–2019 (N = 27,949). Table 1. Characteristics of participants according to IBS status, NutriNet-Santé cohort, France, 2009–2019 (N = 27,949). Table 1. Characteristics of participants according to IBS status, NutriNet-Santé cohort, France, 2009–2019 (N = 27,949). Table 1. Characteristics of participants according to IBS status, NutriNet-Santé cohort, France, 2009–2019 Table 1. Characteristics of participants according to IBS status, NutriNet-Santé cohort, France, 2009–2019 (N Table 1. Characteristics of participants according to IBS status, NutriNet Santé cohort, France, 2009 2019 (N 27,949). 2.4. Statistical Analyses Statistical analyses were carried out using SAS software (version 9.4; SAS Institute, Inc., Cary, NC, USA) [45]. 2.4. Statistical Analyses A description of socio-demographic, lifestyle and anthropometric characteristics, health status, physical activity, overall diet quality and FODMAP consumption (total and individually) was performed on the whole sample, and according to the IBS status (yes/no). Chi-square tests or Student’s t-tests were used according to the qualitative or quantitative status of the variable. In order to adjust for the overall diet quality, a principal component analysis was performed using food groups from the study population. The first dietary pattern was positively correlated with fruits and vegetables, whole grains, natural oilseeds, vegetable fat, non-sugared beverages, legumes and broth. It was negatively correlated with milky desserts, meat and ham, sweetened beverages, cakes, cookies and pastries, bread and processed meat. Therefore, it was labelled a “healthy” dietary pattern as previously published [42,43] and this dimension was used as a proxy for the overall diet quality. The estimate of the first principal component was divided into 3 categories (poor qual- ity/intermediate quality or healthy diet). Multivariate logistic regression models were applied to assess Odds Ratio (OR) and adjusted OR (aOR) with their 95% confidence intervals (95% CI) of IBS across FODMAP consumption. Models were successively adjusted for age and sex (model 2) as well as Nutrients 2021, 13, 4513 4 of 13 OR) and ODMAP energy, BMI, income per consumption unit, marital status, smoking status, overall diet quality, IPAQ, residence and educational level (model 3). All tests were two-sided and a p-value < 0.05 was considered statistically significant. Statistical analyses were carried out using SAS software (version 9.4; SAS Institute, Inc., Cary, NC, USA) [44]. gy, , p p , , g , q ity, IPAQ, residence and educational level (model 3). All tests were two-sided and a p- value < 0.05 was considered statistically significant. Statistical analyses were carried out using SAS software (version 9.4; SAS Institute, Inc., Cary, NC, USA) [45]. energy, BMI, income per consumption unit, marital status, smoking status, overall diet quality, IPAQ, residence and educational level (model 3). All tests were two-sided and a p-value < 0.05 was considered statistically significant. Statistical analyses were carried out using SAS software (version 9.4; SAS Institute, Inc., Cary, NC, USA) [44]. gy, , p p , , g , q ity, IPAQ, residence and educational level (model 3). All tests were two-sided and a p- value < 0.05 was considered statistically significant. 3.1. Population 3.1. Population Th fi l Characteristics of Participants All IBS (Yes) IBS (No) p-Value N = 27,949 N = 1295 (4.63%) N = 26,654 (95.37%) n % n % n % Age (years) mean (SD) 47.8 (14.1) 43.4 (14.5) 48.0 (14.1) <0.0001 Energy (kcal) mean (SD) 1903 (495) 1859 (488) 1905 (496) <0.0001 Sex Men 6871 24.6 149 11.5 6722 25.2 <0.0001 Women 21,078 75.4 1146 88.5 19,932 74.8 Marital status Single/divorced/widowed 7565 27.1 412 31.9 7153 26.9 <0.0001 Married/cohabiting 20,327 72.7 881 68.1 19,446 73.1 Educational level No diploma or primary school 712 2.57 28 2.18 684 2.59 0.26 Secondary school 8573 30.9 371 28.9 8202 31.0 p p g ( ) Characteristics of Participants All IBS (Yes) IBS (No) p-Value N = 27,949 N = 1295 (4.63%) N = 26,654 (95.37%) n % n % n % Age (years) mean (SD) 47.8 (14.1) 43.4 (14.5) 48.0 (14.1) <0.0001 Energy (kcal) mean (SD) 1903 (495) 1859 (488) 1905 (496) <0.0001 Sex Men 6871 24.6 149 11.5 6722 25.2 <0.0001 Women 21,078 75.4 1146 88.5 19,932 74.8 Marital status Single/divorced/widowed 7565 27.1 412 31.9 7153 26.9 <0.0001 Married/cohabiting 20,327 72.7 881 68.1 19,446 73.1 Educational level No diploma or primary school 712 2.57 28 2.18 684 2.59 0.26 Secondary school 8573 30.9 371 28.9 8202 31.0 Undergraduate 8372 30.2 407 31.7 7965 30.1 Graduate 10,059 36.3 479 37.3 9580 36.2 Income per consump- tion unit (€/month) Unwilling to answer 2034 7.50 78 6.27 1956 7.56 <0.0001 <1110 3101 11.4 198 15.9 2903 11.2 1110–2330 17,932 66.2 821 65.9 17,111 66.2 >2330 4040 14.9 148 11.9 3892 15.0 Residence Rural area 6051 22.1 255 20.2 5796 22.2 0.10 Urban area 21,350 77.9 1007 79.8 20,343 77.8 5 of 13 Nutrients 2021, 13, 4513 Table 1. Cont. 3.2. Dietary Patterns and Proportion of IBS Cases in the Study Population 3.2. Dietary Patterns and Proportion of IBS Cases in the Study Population Overall 1295 (4.6%) subjects reported an IBS based on Rome IV criteria, with a higher proportion in women compared to men (5.44% in women vs. 2.17% in men, p-value < 0.0001). They were also more likely to be current smoker, younger, single, with a lower income (all p-value < 0.0001) and to have a healthier diet than non-IBS participants (p-value = 0.003) (Table 1). IBS subjects tended to have lower energy intakes than non-IBS ones (1859 ± 488 kcal vs. 1906 ± 496 kcal, p-value < 0.0001). Their average total consumption of FODMAPs was 18.4 (SD = 9.6) g/day vs. 19.5 (SD = 9.5) g/day in non-IBS participants (∆= −1.1 g/day, i.e., −6.0%, p-value < 0.0001). Moreover, IBS participants tended to have significantly lower intakes in excess fructose (∆= −0.46 g/day, i.e., −11.0%), lactose (∆= −0.2 g/day, i.e., −2.0%), GOS (∆= −0.03 g/day, i.e., −8.3%), fructans (∆= −0.12 g/day, i.e., −5.7%) and polyols (∆= −0.22 g/day, i.e., −12.9%) (Table 2). Table 2. FODMAP intake in the population under study according to the IBS, NutriNet-Santé cohort, France, 2009–2019 (N = 27,949). AP intake in the population under study according to the IBS, NutriNet-Santé cohort, France, 2009–2019 Table 2. FODMAP intake in the population under study according to the IBS, NutriNet-Santé cohort, France, 2009–2019 (N = 27,949). Global IBS (Yes) IBS (No) p-Value N = 27,949 N = 1295 (4.6%) N = 26,654 (95.4%) Mean SD Mean SD Mean SD Energy (kcal) 1903 495 1859 488 1906 496 <0.0001 Total FODMAPs (g/day) 19.4 9.5 18.4 9.6 19.5 9.5 <0.0001 Excess fructose 4.62 3.92 4.18 3.96 4.64 3.91 <0.0001 Lactose 10.3 7.5 10.1 7.3 10.3 7.5 <0.0001 GOS 0.39 0.37 0.36 0.38 0.39 0.37 <0.0001 Fructans 2.28 1.64 2.10 1.49 2.22 1.64 <0.0001 Polyols 1.92 2.05 1.71 2.00 1.93 2.06 <0.0001 IBS: Irritable bowel syndrome. 3.1. Population 3.1. Population Th fi l Characteristics of Participants All IBS (Yes) IBS (No) p-Value N = 27,949 N = 1295 (4.63%) N = 26,654 (95.37%) n % n % n % Smoking status Current smoker 3366 12.1 204 15.8 3162 11.9 0.0001 Former 10,070 36.1 437 33.8 9633 36.2 Never 14,458 51.8 652 50.4 13,806 51.9 BMI (kg/m2) <18.5 1300 4.66 90 6.96 1210 4.55 <0.0001 18.5–25 17,932 64.3 784 60.6 17,148 64.4 25–30 6355 22.8 276 21.3 6079 22.8 ≥30 2319 8.31 144 11.1 2175 8.17 IPAQ Intense 8693 35.0 372 32.5 8321 35.1 0.16 Moderate 10,705 43.1 508 44.3 10,197 43.0 Low 5433 21.9 266 23.2 5167 21.8 BMI: Body Mass Index; IBS: Irritable Bowel Syndrome; IPAQ: International Physical Activity Questionnaire; SD: Standard Deviation; p-value: Chi-square tests or Student’s t-tests were used according to the qualitative or quantitative status of the characteristics; Missing data: Physical activity N = 3118 (11.2%); <5%: income level, residence, educational level, marital status, smoking status, BMI. Table 1. Cont. Table 1. Cont. BMI: Body Mass Index; IBS: Irritable Bowel Syndrome; IPAQ: International Physical Activity Questionnaire; SD: Standard Deviation; p-value: Chi-square tests or Student’s t-tests were used according to the qualitative or quantitative status of the characteristics; Missing data: Physical activity N = 3118 (11.2%); <5%: income level, residence, educational level, marital status, smoking status, BMI. 3.2. Dietary Patterns and Proportion of IBS Cases in the Study Population 3.3. Association between FODMAP Consumption and IBS After adjusting for covariates (model 3), an increase in total FODMAP intakes was as- sociated with a reduced proportion of IBS (Table 3). The result was similar using FODMAP consumption as continuous (aOR: 0.88, 95% CI: 0.82–0.95, p-value: 0.001) or categorical: consumers with a high load of FODMAPs (i.e., >16 g/day) were less likely to be IBS patients in comparison with people with a low amount of FODMAPs (i.e., <9 g/day) (aOR: 0.82, 95% CI: 0.67–1.01, p for trend: 0.009) (Table 3). Sensitivity analyses were performed using 20 multiple imputations by the Chained equations method to handle missing values for Nutrients 2021, 13, 4513 6 of 13 the following variables: IPAQ (11.2%), income level (3.0%), residence (2.0%), educational level (0.8%), marital status (0.2%), smoking status (0.2%), BMI (0.2%) [45,46]. The results were similar, with an association between FODMAP consumption and IBS (model 3 aOR: 0.900 95% CI: 0.827–0.980) (data not tabulated). the following variables: IPAQ (11.2%), income level (3.0%), residence (2.0%), educational level (0.8%), marital status (0.2%), smoking status (0.2%), BMI (0.2%) [45,46]. The results were similar, with an association between FODMAP consumption and IBS (model 3 aOR: 0.900 95% CI: 0.827–0.980) (data not tabulated). the following variables: IPAQ (11.2%), income level (3.0%), residence (2.0%), educational level (0.8%), marital status (0.2%), smoking status (0.2%), BMI (0.2%) [45,46]. The results were similar, with an association between FODMAP consumption and IBS (model 3 aOR: 0.900 95% CI: 0.827–0.980) (data not tabulated). Table 3. Adjusted associations between FODMAP consumption and Irritable bowel syndrome, NutriNet-Santé cohort, France, 2009–2019 (N = 27,949). Continuous Classes ≤9 g 9–16 g >16 g N = 2792 N = 8865 N = 16,292 OR 95% CI p-Value OR 95% CI OR 95% CI p-Trend IBS Model 1 0.88 [0.83–0.94] <0.0001 Ref 0.90 [0.75–1.09] 0.77 [0.64–0.92] 0.0005 Model 2 0.92 [0.86–0.98] 0.0066 Ref 0.93 [0.77–1.13] 0.82 [0.69–0.99] 0.0110 Model 3 0.88 [0.82–0.95] 0.0011 Ref 0.99 [0.80–1.22] 0.82 [0.67–1.01] 0.0086 p-values obtained with logistic regression using total FODMAPs as a continuous variable. p-values for trend obtained with logistic regression using classes as continuous variables. Model 1: Not adjusted; Model 2: Adjusted for age and sex; Model 3: Adjusted for model 2 + energy intake, BMI, income, marital status, smoking status, diet quality, physical activity, residence, and educational level. 3.3. Association between FODMAP Consumption and IBS ions between FODMAP consumption and Irritable bowel syndrome, NutriNet-Santé cohort, 949) ed associations between FODMAP consumption and Irritable bowel syndrome, NutriNet-Santé cohort, 9 (N = 27,949). Table 3. Adjusted associations between FODMAP consumption and Irritable bowel syndrome, NutriN France, 2009–2019 (N = 27,949). 3.4. FODMAP Consumption and IBS Severity Proportion of IBS participants with different FODMAP intakes in different categories of severity according to the IBS-SSS, NutriNet-Santé cohort, France, 2009–2019 (N = 803). igure 2. Proportion of IBS participants with different FODMAP intakes in different categories of everity according to the IBS-SSS, NutriNet-Santé cohort, France, 2009–2019 (N = 803). 7.7 11.7 9.9 20.0 33.3 34.5 36.8 29.3 59.0 53.7 53.3 50.7 0.0% 20.0% 40.0% 60.0% 80.0% 100.0% Remission Mild Moderate Severe <9g 9–16g >16g Figure 2. Proportion of IBS participants with different FODMAP intakes in different categories of severity according to the IBS-SSS, NutriNet-Santé cohort, France, 2009–2019 (N = 803) Figure 2. Proportion of IBS participants with different FODMAP intakes in different categories of severity according to the IBS-SSS, NutriNet-Santé cohort, France, 2009–2019 (N = 803). gure 2. Proportion of IBS participants with different FODMAP intakes in different categories of verity according to the IBS-SSS, NutriNet-Santé cohort, France, 2009–2019 (N = 803). Focusing specifically on each IBS-SSS individual item, among people who were di- agnosed with an IBS through the Rome IV criteria, those who consumed less than 9 g of total FODMAPs per day had more severe IBS symptoms in particular for abdominal pain and distension than the others (Figure 3) Focusing specifically on each IBS-SSS individual item, among people who were diag- nosed with an IBS through the Rome IV criteria, those who consumed less than 9 g of total FODMAPs per day had more severe IBS symptoms in particular for abdominal pain and distension than the others (Figure 3). Focusing specifically on each IBS-SSS individual item, among people who were di- gnosed with an IBS through the Rome IV criteria, those who consumed less than 9 g of otal FODMAPs per day had more severe IBS symptoms in particular for abdominal pain nd distension than the others (Figure 3). Figure 3. IBS-SSS individual items according to FODMAP intakes in IBS patients identified with the 0.0 10.0 20.0 30.0 40.0 50.0 60.0 Abdominal pain severity Abdominal pain frequency Abdominal distension severity Bowel habit satisfaction Impact on quality of life <9g 9–16g >16g igure 3. IBS-SSS individual items according to FODMAP intakes in IBS patients identified with the Rome IV criteria, NutriNet-Santé cohort, France, 2009–2019 (N = 803). 0.0 10.0 20.0 30.0 40.0 50.0 60.0 Abdominal pain severity Abdominal pain frequency Abdominal distension severity Bowel habit satisfaction Impact on quality of life <9g 9–16g >16g Figure 3. 3.4. FODMAP Consumption and IBS Severity Out of 27,949 participants for this study, 3979 answered the IBS-SSS, based on a self-diagnosis for IBS. Among them, 20.2% (N = 803) met the Rome IV criteria for IBS. Participants with an auto-diagnosed IBS were similarly distributed among each FODMAP category (<9 g/day, 9–16 g/day, ≥16 g/day) with the others. Indeed, 12% consumed less than 9 g/day of total FODMAPs in comparison with 54% who ate more than 16 g/day of total FODMAPs. The average total consumption of FODMAPs was 18.69 ± 9.55 g/day for those with an auto-diagnosis of IBS in comparison with 19.58 ± 9.55 g/day for the others (data not tabulated). 55% of IBS participants had at least moderate or severe symptoms according to the IBS-SSS (Table 4). 55% of IBS participants had at least moderate or severe symptoms according to the IBS-SSS (Table 4). Table 4. Proportion of IBS participants in different categories of severity according to the IBS-SSS, NutriNet-Santé cohort, France, 2009-2019 (N = 803). IBS-SSS n % Remission 0–75 78 9.7 Mild 75–175 281 35.0 Moderate 175–300 304 37.9 Severe >300 140 17.4 Table 4. Proportion of IBS participants in different categories of severity according to the IBS-SSS, NutriNet-Santé cohort, France, 2009-2019 (N = 803). Among people who ate less than 9 g per day of total FODMAPs (N = 97, 12% of participants), the mean IBS-SSS was 228 ± 103. People who ate 9–16 g per day of total FODMAPs had an average IBS-SSS of 199 ± 97 whereas among people who ate more than 16 g per day of total FODMAPs (N = 430, 54% of participants), the mean IBS-SSS was 197 ± 98 (data not tabulated, p-value within each class 0.06). Among severe cases of IBS participants, 20% ate less than 9 g of FODMAPs per day contrary to 51% of severe cases of IBS participants who ate more than 16 g of FODMAPs per day (Figure 2). 7 of 13 er day MAPs APs Nutrients 2021, 13, 4513 Figure 2. Proportion of IBS participants with different FODMAP intakes in different categories of severity according to the IBS-SSS, NutriNet-Santé cohort, France, 2009–2019 (N = 803). 7.7 11.7 9.9 20.0 33.3 34.5 36.8 29.3 59.0 53.7 53.3 50.7 0.0% 20.0% 40.0% 60.0% 80.0% 100.0% Remission Mild Moderate Severe <9g 9–16g >16g Figure 2. 3.4. FODMAP Consumption and IBS Severity IBS-SSS individual items according to FODMAP intakes in IBS patients identified with the Rome IV criteria, NutriNet-Santé cohort, France, 2009–2019 (N = 803). Abdominal pain Abdominal pain frequency Figure 3 IBS SSS individual items according to FODMAP intakes in IBS patients identified with the <9g 9–16g >16g gure 3. IBS-SSS individual items according to FODMAP intakes in IBS patients identified with the me IV criteria NutriNet-Santé cohort France 2009–2019 (N = 803) Figure 3. IBS-SSS individual items according to FODMAP intakes in IBS patients identified with the Rome IV criteria, NutriNet-Santé cohort, France, 2009–2019 (N = 803). g Rome IV criteria, 4. Discussion p g p p In this study, although a small but significant difference in total FODMAP intake was found between IBS participants and controls, both intakes in FODMAPs are in the range of those known to be associated with symptoms in patients, i.e., over 9 g per day (32). These intakes and higher FODMAP intakes (over 16 g/day) are therefore susceptible to induce digestive symptoms in participants with a favoring profile for developing IBS such as a particular microbiota [53], visceral hypersensitivity [54] or altered intestinal permeability [55]. Interestingly, in our study, the mean daily intake in FODMAPs was slightly lower than that of non-IBS participants, and we found an inverse relationship between the level of FODMAP consumption and the prevalence of IBS; that is to say an increased intake in FODMAPs was associated with a lower prevalence of IBS. Reverse causality could partly explain these results, i.e., exposure to low loads of FODMAPs may be the consequence of IBS incidence. Indeed, we used a cross-sectional design (even though we tried to be as prospective as possible by choosing a dietary recall prior to the Rome IV questionnaire). One hypothesis is that patients, aware of the low FODMAP diet (LFD) benefits on digestive symptoms, follow dietary advice to reduce their FODMAP load. This is confirmed by the fact that patients with a more severe disease according to global IBS-SSS or individual component of the score (pain, abdominal distension, impact on quality of life) were those with lower FODMAP consumption as if they were following a diet. Given the nature of symptoms in IBS, directly linked in the patients’ mind to their diet [56], it may be difficult to disentangle causality in the relationship between FODMAPs and IBS in observational studies. However, it has been shown in the US that 60% of IBS patients described an association between consuming foods and GI symptoms and that they have frequent concerns about what food to avoid [57,58]. In people using the internet like our participants to an online study, information about disease is more frequently found on the internet and other media than in non-internet users, which could potentially lead to self- management [59,60]. g Rome IV criteria, 4. Discussion In this cross-sectional study performed in a large French cohort involving more than 27,000 people, we found that 4.6% of the participants had an IBS using the Rome IV criteria. Total FODMAP intake was around 19 g per day in both IBS and non IBS participants. However, IBS patients had a slightly lower intake of FODMAPs than non IBS participants and an increased severity of disease was associated with decreased intakes in FODMAPs. The Rome IV proportion of 4.6% of IBS participants we found in this study compared with the 10.5% in our last study using the Rome III criteria [47] is consistent with a decrease in prevalence using the Rome IV criteria instead of the Rome III one [48,49]. p g To the best of our knowledge, this work is the first to assess FODMAP consumption in both IBS and non-IBS subjects in such a large population-based study. FODMAP Nutrients 2021, 13, 4513 8 of 13 intakes have already been studied in other countries in smaller studies. In Australia, an interventional study with a diet low in FODMAPs included 30 patients with IBS and 8 healthy controls and was associated with reduced functional gastrointestinal symptoms in patients with IBS [5]. In this study as well as in other studies, FODMAP intakes in both groups of IBS patients at baseline was similar at around 16 g per day [34,50,51]. These levels are of similar range but lower than the consumption we found in our study in both groups. Surprisingly, while we expected that the FODMAP content in the typical Australian diet would be higher than that of a French diet, it was not confirmed. The higher FODMAP consumption found in France in IBS subjects, around 19 g, compared with the 16.5 g per day of Australian and Swedish study is due to an increase in the excess fructose and polyol categories while lactose and GOS intakes are similar [5,50]. However, this total FODMAP intake of around 19 g in both groups is in accordance with our recent publication in more than 100,000 participants of the NutriNet cohort [32] and of 117 Swedish invidious representative of the general population [52]. g Rome IV criteria, 4. Discussion A recent study in the US showed that half of the patients have tried an LFD before being seen by a gastroenterologist [58] and it was the same proportion in a recent study with patients from the French IBS association [61]. Furthermore, gastroenterologists themselves show a growing body of interest for diets, in particular the LFD: half of the providers now provide diet recommendations to over 75% of their IBS patients and they mostly recommend an LFD [58]. Indeed, most interventional studies showed a decrease in IBS severity after an LFD [5,24,50,51,62]. A prospective trial in the United States showed an improvement of quality of life in patients with diarrhea-predominant IBS with the very low carbohydrate diet in comparison with the standard American diet [63]. Conversely, a randomized, controlled, single-blinded trial in Sweden concluded that both an LFD and traditional IBS dietary advice improved IBS symptoms, but without any significant difference between the two dietary strategies [50]. Besides, though some have argued for a causal effect of FODMAP consumption on IBS symptoms, with small bowel luminal distension, colonic gas production varying with the Nutrients 2021, 13, 4513 9 of 13 type of FODMAP and influenced by gut microbiota [64], and visceral hypersensitivity [54], the association between FODMAP consumption and IBS is still controversial as seen elsewhere [22,50,65–68]. Another explanation could be that FODMAPs encompass lactose, and lactose intolerance is an analogous condition to IBS [69]. Moreover, FODMAP effects could be related to other food items such as fatty food or coffee that are not included in FODMAP definition [70,71]. type of FODMAP and influenced by gut microbiota [64], and visceral hypersensitivity [54], the association between FODMAP consumption and IBS is still controversial as seen elsewhere [22,50,65–68]. Another explanation could be that FODMAPs encompass lactose, and lactose intolerance is an analogous condition to IBS [69]. Moreover, FODMAP effects could be related to other food items such as fatty food or coffee that are not included in FODMAP definition [70,71]. This study has several strengths: First, a large number of participants were involved, allowing powerful analyses. Besides, for IBS definition, we used a validated question- naire [10,72], as well as validated methods to assess FODMAP intakes [32]. The Rome IV questionnaire is also believed to select a more severe subpopulation from the IBS patients who were defined with the Rome III questionnaire [73–75]. g Rome IV criteria, 4. Discussion Furthermore, socio- demographic characteristics of IBS patients in this study are consistent with the literature: IBS is more prevalent among young women and those with lower incomes [7,8,11]. This study also had a high specificity as the eligibility criteria—in particular regarding self- reported medical conditions and alert symptoms—was very restrictive, which probably led to the exclusion of healthy people. NutriNet-Santé study is a web-based study, thus enablingthe collection of data from various socio-demographic profiles, which allowed the use of multiple covariates to adjust for confounders. The results were adjusted for age, sex, energy, BMI, income per consumption unit, marital status, smoking status, overall diet quality, physical activity, residence and educational level, therefore minimizing some potentially confounding factors. Several limitations of this study should be discussed. First, even though the work was designed to be as prospective as possible by choosing dietary records prior to the Rome IV questionnaire, it is still a cross-sectional study. Because of the observational design of the study, causal links cannot be asserted and the question of whether they were following a diet, and in particular an LFD was not directly asked to the participants. However, the hypothesis of reverse causality was reinforced by the analyses performed using the IBS-SSS. Indeed, since the LFD is increasingly known among IBS patients, they might have modified their dietary behavior before filling in the Rome IV questionnaire. The 9 g/day cut-off used in our study was chosen according to previous works of the Monash group [5,33] whereas the 16 g/day cut-off matches the usual daily amount of FODMAPs reached in several studies [5,34,50]. Further research from longitudinal studies could point out if FODMAP intakes tend to decrease after IBS onset and diagnosis. Another limitation relates to the voluntary profile of subjects, thus, subjects probably more interested in nutrition. They were therefore more likely to have a healthier diet compared to the general population, thus potentially leading to an underestimation of the associations that would be found in the general population. Consequently, caution is needed before generalization of the results. Another limitation is that the dietary records as well as the Rome IV questionnaire were administered by self-administered questionnaire. Nevertheless, this food collection system has been shown to be reliable [29–31]. Finally, even though potential confounding factors were taken into account, the study design does not enable to exclude the hypothesis of residual confounders. 5. Conclusions In this large prospective population-based cohort, participants had a mean intake in FODMAPs of about 19 g per day. IBS patients had slightly lower intakes in FODMAPs than non-IBS participants. This may be due to reverse causality, as it was reinforced by the disease severity. Longitudinal studies are needed to better assess these findings, and to give clinicians new data on FODMAP intakes as a triggering factor for IBS symptoms. Author Contributions: E.S. analysed the data, interpreted the results and drafted and revised the paper. J.-M.S., M.B. and R.B. participated in the design of the study, helped in the interpretation of the data and critically revised the manuscript for important intellectual content. M.T. and S.H. implemented the study and monitored data collection for the whole NutriNet-Santé study and critically revised the paper for important intellectual content. C.J. participated in the design of the Nutrients 2021, 13, 4513 10 of 13 10 of 13 study, interpretation of the data and critically revised the paper for important intellectual content. C.B. supervised the statistical analysis outline, analysed the data and critically revised the paper for important intellectual content. She has full responsibility for the conduct of the study and final content. All authors have read and agreed to the published version of the manuscript. Funding: The NutriNet-Santé study is supported by the following public institutions: Ministère de la Santé, Santé publique France (SPF), Institut National de la Santé et de la Recherche Médicale (INSERM), Institut National de la Recherche Agronomique (INRA), Conservatoire National des Arts et Métiers (CNAM), and Université Paris 13. The Société Nationale Française de Gastroentérologie (SNFGE) funded this project in particular with a Fond d’Aide à la Recherche et à l’Evaluation (FARE) grant. Institutional Review Board Statement: This study was conducted in accordance with the Decla- ration of Helsinki, and was approved by the Institutional Review Board of the French Institute for Health and Medical Research (IRB Inserm 0000388FWA00005831) and the “Commission Na- tionale de l’Informatique et des Libertés” (CNIL n 908450 and 909216). The study is registered at clinicaltrials.gov (accessed on 21 May 2019) as NCT03335644. All participants provided an electronic informed consent. Informed Consent Statement: Electronic informed consent was obtained from all subjects involved in the study. Data Availability Statement: Data available upon request due to restrictions, e.g., privacy or ethical. The data presented in this study are available upon request from the corresponding author. 5. Conclusions Acknowledgments: The authors thank Cynthia Perlin (dietitian) and Nathalie Arnault (computer scientist) for the elaboration of the FODMAP composition table. We also thank Cédric Agaesse, Anne-Elise Dussoulier, Vristi Desan (dietitians); Thi Hong Van Duong, Younes Esseddik (IT manager), Paul Flanzy, Régis Gatibelza, Jagatjit Mohinder and Aladi Timera (computer scientists); Julien Allegre, Laurent Bourhis and Fabien Szabo de Edelenyi, (supervisor) (data-manager/statisticians) for their technical contribution to the NutriNet-Santé study and Nathalie Druesne-Pecollo, (operational manager). We thank all the volunteers of the NutriNet-Santé cohort. Conflicts of Interest: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results. References 1. Gibson, P.R. Food Intolerance in Functional Bowel Disorders: Food Intolerance. J. Gastroenterol. Hepatol. 2011, 26, 128–131. [CrossRef] ntolerance in Functional Bowel Disorders: Food Intolerance. J. Gastroenterol. Hepatol. 2011, 26, 128–131 2. Rumessen, J.J. Fructose and Related Food Carbohydrates. Sources, Intake, Absorption, and Clinical Implications. Scand. J. Gastroenterol. 1992, 27, 819–828. [CrossRef] 3 Sh h d S J P k F C M i J G Gib PR Di T i f Abd i l S i P i i h I i bl B l 3. Shepherd, S.J.; Parker, F.C.; Muir, J.G.; Gibson, P.R. Dietary Triggers of Abdominal Symptoms in Patients with Irritable Bowel Syndrome: Randomized Placebo-Controlled Evidence. Clin. Gastroenterol. Hepatol. 2008, 6, 765–771. [CrossRef] [PubMed] b h h d d d f l l h 3. Shepherd, S.J.; Parker, F.C.; Muir, J.G.; Gibson, P.R. Dietary Triggers of Abdominal Symptoms in Patients with Irritable Bowel Syndrome: Randomized Placebo-Controlled Evidence. Clin. Gastroenterol. Hepatol. 2008, 6, 765–771. [CrossRef] [PubMed] 4. Gibson, P.R.; Shepherd, S.J. Evidence-Based Dietary Management of Functional Gastrointestinal Symptoms: The FODMAP A h J G t t l H t l 2010 25 252 258 [C R f] [P bM d] p , J ; , ; , J ; , y gg y p Syndrome: Randomized Placebo-Controlled Evidence. Clin. Gastroenterol. Hepatol. 2008, 6, 765–771. [CrossRef] [PubMed] 4. Gibson, P.R.; Shepherd, S.J. Evidence-Based Dietary Management of Functional Gastrointestinal Symptoms: The FODMAP Approach. J. Gastroenterol. Hepatol. 2010, 25, 252–258. [CrossRef] [PubMed] 4. Gibson, P.R.; Shepherd, S.J. Evidence-Based Dietary Management of Funct Approach. J. Gastroenterol. Hepatol. 2010, 25, 252–258. [CrossRef] [PubMed] 5. Halmos, E.P.; Power, V.A.; Shepherd, S.J.; Gibson, P.R.; Muir, J.G. A Diet Low in FODMAPs Reduces Symptoms of Irritable Bowel Syndrome. Gastroenterology 2014, 146, 67–75.e5. [CrossRef] y gy 6. Hungin, A.P.S.; Whorwell, P.J.; Tack, J.; Mearin, F. The Prevalence, Patterns and Impact of Irritable Bowel Syndrome: An International Survey of 40,000 Subjects. Aliment. Pharmacol. Ther. 2003, 17, 643–650. [CrossRef] y j 7. Corazziari, E. Definition and Epidemiology of Functional Gastrointestinal Disorders. Best Pract. Res. Clin. Gastroenterol. 2004, 18, 613–631. [CrossRef] [PubMed] 8. Lovell, R.M.; Ford, A.C. Global Prevalence of and Risk Factors for Irritable Bowel Syndrome: A Meta-Analysis. Clin. Gastroenterol. Hepatol. 2012, 10, 712–721.e4. [CrossRef] 9. Drossman, D.A.; Hasler, W.L. Rome IV-Functional GI Disorders: Disorders of Gut-Brain Interaction. Gastroenterology 2016, 150, 1257–1261. [CrossRef] 9. Drossman, D.A.; Hasler, W.L. Rome IV-Functional GI Disorders: Disorders of Gut-Brain Interaction. References Table de Composition des Aliments; Economica: Paris, France, 2013; ISBN 978-2-7178-6537-0. 29. Touvier, M.; Kesse-Guyot, E.; Méjean, C.; Pollet, C.; Malon, A.; Castetbon, K.; Hercberg, S. Comparison between an Interactive Web-Based Self-Administered 24 h Dietary Record and an Interview by a Dietitian for Large-Scale Epidemiological Studies. Br. J. Nutr. 2011, 105, 1055–1064. [CrossRef] 30. Lassale, C.; Castetbon, K.; Laporte, F.; Camilleri, G.M.; Deschamps, V.; Vernay, M.; Faure, P.; Hercberg, S.; Galan, P.; Kesse-Guyot, E. Validation of a Web-Based, Self-Administered, Non-Consecutive-Day Dietary Record Tool against Urinary Biomarkers. Br. J. Nutr. 2015, 113, 953–962. [CrossRef] [PubMed] 31. Lassale, C.; Castetbon, K.; Laporte, F.; Deschamps, V.; Vernay, M.; Camilleri, G.M.; Faure, P.; Hercberg, S.; Galan, P.; Kesse-Guyot, E. Correlations between Fruit, Vegetables, Fish, Vitamins, and Fatty Acids Estimated by Web-Based Nonconsecutive Dietary Records and Respective Biomarkers of Nutritional Status. J. Acad. Nutr. Diet. 2016, 116, 427–438.e5. [CrossRef] 31. Lassale, C.; Castetbon, K.; Laporte, F.; Deschamps, V.; Vernay, M.; Camilleri, G.M.; Faure, P.; Hercberg, S.; Galan, P.; Kesse-Guyot, E. Correlations between Fruit, Vegetables, Fish, Vitamins, and Fatty Acids Estimated by Web-Based Nonconsecutive Dietary ds and Respective Biomarkers of Nutritional Status. J. Acad. Nutr. Diet. 2016, 116, 427–438.e5. [CrossRef] ider, E.; Sabate, J.-M.; Bouchoucha, M.; Debras, C.; Touvier, M.; Hercberg, S.; Benamouzig, R.; Buscail, C.; Julia Records and Respective Biomarkers of Nutritional Status. J. Acad. Nutr. Diet. 2016, 116, 427 438.e5. [Cross Schneider, E.; Sabate, J.-M.; Bouchoucha, M.; Debras, C.; Touvier, M.; Hercberg, S.; Benamouzig, R.; Buscail, 32. Schneider, E.; Sabate, J.-M.; Bouchoucha, M.; Debras, C.; Touvier, M.; Hercberg, S.; Benamouzig, R.; Buscail, C.; Julia, C. FODMAP Consumption by Adults from the French Population-Based NutriNet-Santé Cohort. J. Nutr. 2021, 151, 3180–3186. [CrossRef] Consumption by Adults from the French Population-Based NutriNet-Santé Cohort. J. Nutr. 2021, 151, 3180–3186. [CrossRef] 33. Ong, D.K.; Mitchell, S.B.; Barrett, J.S.; Shepherd, S.J.; Irving, P.M.; Biesiekierski, J.R.; Smith, S.; Gibson, P.R.; Muir, J.G. Manipulation of Dietary Short Chain Carbohydrates Alters the Pattern of Gas Production and Genesis of Symptoms in Irritable Bowel Syndrome. J. Gastroenterol. Hepatol. 2010, 25, 1366–1373. [CrossRef] J p , , [ ] 34. Staudacher, H.M.; Ralph, F.S.E.; Irving, P.M.; Whelan, K.; Lomer, M.C.E. Nutrient Intake, Diet Quality, and Diet Diversity in Irritable Bowel Syndrome and the Impact of the Low FODMAP Diet. J. Acad. Nutr. Diet. 2019, 120, 535–547. [CrossRef] 35. Black, A.E. Critical Evaluation of Energy Intake Using the Goldberg Cut-off for Energy Intake:Basal Metabolic Rate. References Gastroenterology 2016, 150, 1257–1261. [CrossRef] 10. Drossman, D.A. Functional Gastrointestinal Disorders: History, Pathophysiology, Clinical Features, and Rome IV. Gastroenterology Functional Gastrointestinal Disorders: History, Pathophysiology, Clinical Features, and Rome IV. Gastroentero 1279.e2. [CrossRef] 10. Drossman, D.A. Functional Gastrointestinal Disorders: History, Pathophysiology, Clinical Features, a 2016, 150, 1262–1279.e2. [CrossRef] 11. Dapoigny, M.; Bellanger, J.; Bonaz, B.; Bruley des Varannes, S.; Bueno, L.; Coffin, B.; Ducrotté, P.; Flourié, B.; Lémann, M.; Lepicard, A.; et al. Irritable Bowel Syndrome in France: A Common, Debilitating and Costly Disorder. Eur. J. Gastroenterol. Hepatol. 2004, 16, 995–1001. [CrossRef] [PubMed] 11 of 13 11 of 13 Nutrients 2021, 13, 4513 12. Talley, N.J. Functional Gastrointestinal Disorders as a Public Health Problem. Neurogastroenterol. Motil. 2008, 20, 121–129. [CrossRef] [PubMed] [ ] [ ] 13. Staudacher, H.M.; Whelan, K. The Low FODMAP Diet: Recent Advances in Understanding Its Mechanisms and Efficacy in IBS. Gut 2017, 66, 1517–1527. [CrossRef] 14. Lacy, B.E. The Science, Evidence, and Practice of Dietary Interventions in Irritable Bowel Syndrome. Clin. Gastroenterol. Hepatol. 2015, 13, 1899–1906. [CrossRef] 15. Hill, P.; Muir, J.G.; Gibson, P.R. Controversies and Recent Developments of the Low-FODMAP Diet. Gastroenterol. Hepatol. 2017, 13, 36–45. 16. Eswaran, S. Low FODMAP in 2017: Lessons Learned from Clinical Trials and Mechanistic Studies. Neurogastroenterol. Motil. 2017, 29, e13055. [CrossRef] 17. Barrett, J.S.; Gibson, P.R. Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols (F gic Food Intolerance: FODMAPs or Food Chemicals? Ther. Adv. Gastroenterol. 2012, 5, 261–268. [CrossR 18. Ahmad, O.F.; Akbar, A. Dietary Treatment of Irritable Bowel Syndrome. Br. Med. Bull. 2015, 113 18. Ahmad, O.F.; Akbar, A. Dietary Treatment of Irritable Bowel Syndrome. Br. Med. Bull. 2015, 113, 83–90. [CrossRef] [PubMed] 19 McIntosh K ; Reed D E ; Schneider T ; Dang F ; Keshteli A H ; Palma G D ; Madsen K ; Bercik P; Vanner S FODMAPs Alter 18. Ahmad, O.F.; Akbar, A. Dietary Treatment of Irritable Bowel Syndrome. Br. Med. Bull. 2015, 113, 83–90. [CrossRef] [PubMed] 19. McIntosh, K.; Reed, D.E.; Schneider, T.; Dang, F.; Keshteli, A.H.; Palma, G.D.; Madsen, K.; Bercik, P.; Vanner, S. FODMAPs Alter Symptoms and the Metabolome of Patients with IBS: A Randomised Controlled Trial. Gut 2017, 66, 1241–1251. [CrossRef] g Symptoms and the Metabolome of Patients with IBS: A Randomised Controlled Trial. Gut 2017, 66, 1241–1251. References [CrossRef] 20 St d h H M L M C E F h F M L i P F F F i i E S h l M T h K M Li d J O g ymptoms and the Metabolome of Patients with IBS: A Randomised Controlled Trial. Gut 2017, 66, 1241–1251 toms and the Metabolome of Patients with IBS: A Randomised Controlled Trial. Gut 2017, 66, 1241–1251. [C acher, H.M.; Lomer, M.C.E.; Farquharson, F.M.; Louis, P.; Fava, F.; Franciosi, E.; Scholz, M.; Tuohy, K.M. 20. Staudacher, H.M.; Lomer, M.C.E.; Farquharson, F.M.; Louis, P.; Fava, F.; Franciosi, E.; Scholz, M.; Tuohy, K.M.; Lindsay, J.O.; Irving, P.M.; et al. A Diet Low in FODMAPs Reduces Symptoms in Patients with Irritable Bowel Syndrome and A Probiotic Restores Bifidobacterium Species: A Randomized Controlled Trial. Gastroenterology 2017, 153, 936–947. [CrossRef] Irving, P.M.; et al. A Diet Low in FODMAPs Reduces Symptoms in Patients with Irritable Bowel Syndrome and A Probiotic Restores Bifidobacterium Species: A Randomized Controlled Trial. Gastroenterology 2017, 153, 936–947. [CrossRef] p gy 21. Bellini, M.; Tonarelli, S.; Nagy, A.G.; Pancetti, A.; Costa, F.; Ricchiuti, A.; de Bortoli, N.; Mosca, M.; Marchi, S.; Rossi, A. Low FODMAP Diet: Evidence, Doubts, and Hopes. Nutrients 2020, 12, 148. [CrossRef] [PubMed] 22. Krogsgaard, L.R.; Lyngesen, M.; Bytzer, P. Systematic Review: Quality of Trials on the Symptomatic Diet for Irritable Bowel Syndrome. Aliment. Pharmacol. Ther. 2017, 45, 1506–1513. [CrossRef] y 23. Staudacher, H.M.; Irving, P.M.; Lomer, M.C.E.; Whelan, K. Mechanisms and Efficacy of Dietary FODMAP Restriction in IBS. Nat. Rev. Gastroenterol. Hepatol. 2014, 11, 256–266. [CrossRef] p 24. Marsh, A.; Eslick, E.M.; Eslick, G.D. Does a Diet Low in FODMAPs Reduce Symptoms Associated with Functional Gastrointestinal Disorders? A Comprehensive Systematic Review and Meta-Analysis. Eur. J. Nutr. 2016, 55, 897–906. [CrossRef] 25. Hercberg, S.; Castetbon, K.; Czernichow, S.; Malon, A.; Mejean, C.; Kesse, E.; Touvier, M.; Galan, P. The Nutrinet-Santé Study: A Web-Based Prospective Study on the Relationship between Nutrition and Health and Determinants of Dietary Patterns and Nutritional Status. BMC Public Health 2010, 10, 242. [CrossRef] [PubMed] 26. Mearin, F.; Lacy, B.E.; Chang, L.; Chey, W.D.; Lembo, A.J.; Simren, M.; Spiller, R. Bowel Disorders. Gastroenterology 2016, 150, 1393–1407.e5. [CrossRef] 27. Hercberg, S.; Deheeger, M.; Preziosi, P.; Suvimax. Portions Alimentaires: Manuel Photos pour L’Estimation des Quantités—Su.Vi.Max.; Polytechnica: Paris, France, 2012. y 28. Etude NutriNet-Santé. Table de Composition des Aliments; Economica: Paris, France, 2013; ISBN 978- Net-Santé. References Allès, B.; Péneau, S.; Kesse-Guyot, E.; Baudry, J.; Hercberg, S.; Méjean, C. Food Choice Motives Including Sustainability during Purchasing Are Associated with a Healthy Dietary Pattern in French Adults. Nutr. J. 2017, 16, 58. [CrossRef] [PubMed] y 43. Allès, B.; Péneau, S.; Kesse-Guyot, E.; Baudry, J.; Hercberg, S.; Méjean, C. Food Choice Motives Includ Purchasing Are Associated with a Healthy Dietary Pattern in French Adults. Nutr. J. 2017, 16, 58. [CrossRef] [PubMed] 44. Analytics, Business Intelligence and Data Management. Available online: https://www.sas.com/en_us/home.html (accessed on 24 May 2019). g y y 44. Analytics, Business Intelligence and Data Management. Available online: https://www.sas.com/en_us/home.html (accessed on 24 May 2019). y 45. Schafer, J.L.; Olsen, M.K. Multiple Imputation for Multivariate Missing-Data Problems: A Data Analyst’s Perspective. Multivar. Behav. Res. 1998, 33, 545–571. [CrossRef] 46. Su, Y.-S.; Gelman, A.; Hill, J.; Yajima, M. Multiple Imputation with Diagnostics (Mi) in R: Opening Win J. Stat. Softw. 2011, 45, 1–31. [CrossRef] n, A.; Hill, J.; Yajima, M. Multiple Imputation with Diagnostics (Mi) in R: Opening Windows into the Black 1, 45, 1–31. [CrossRef] f 47. Schnabel, L.; Buscail, C.; Sabate, J.-M.; Bouchoucha, M.; Kesse-Guyot, E.; Allès, B.; Touvier, M.; Monteiro, C.A.; Hercberg, S.; Benamouzig, R.; et al. Association Between Ultra-Processed Food Consumption and Functional Gastrointestinal Disorders: Results from the French NutriNet-Santé Cohort. Am. J. Gastroenterol. 2018, 113, 1217–1228. [CrossRef] [PubMed] 48. Black, C.J.; Yiannakou, Y.; Houghton, L.A.; Ford, A.C. Epidemiological, Clinical, and Psychological Characteristics of Individuals with Self-Reported Irritable Bowel Syndrome Based on the Rome IV vs Rome III Criteria. Clin. Gastroenterol. Hepatol. 2019, 18, 392–398. [CrossRef] 49. Van den Houte, K.; Carbone, F.; Pannemans, J.; Corsetti, M.; Fischler, B.; Piessevaux, H.; Tack, J. Prevalence and Impact of Self-Reported Irritable Bowel Symptoms in the General Population. United Eur. Gastroenterol. J. 2019, 7, 307–315. [CrossRef] [PubMed] 50. Böhn, L.; Störsrud, S.; Liljebo, T.; Collin, L.; Lindfors, P.; Törnblom, H.; Simrén, M. Diet Low in FODMAPs Reduces Symptoms of Irritable Bowel Syndrome as Well as Traditional Dietary Advice: A Randomized Controlled Trial. Gastroenterology 2015, 149, 1399–1407.e2. [CrossRef] [PubMed] 51. Eswaran, S.L.; Chey, W.D.; Han-Markey, T.; Ball, S.; Jackson, K. A Randomized Controlled Trial Comparing the Low FODMAP Diet vs. Modified NICE Guidelines in US Adults with IBS-D. Am. J. Gastroenterol. 2016, 111, 1824–1832. [CrossRef] 52. Liljebo, T.; Störsrud, S.; Andreasson, A. References A Practical Guide to Its Calculation, Use and Limitations. Int. J. Obes. 2000, 24, 1119. [CrossRef] 36. Francis, C.Y.; Morris, J.; Whorwell, P.J. The Irritable Bowel Severity Scoring System: A Simple Method of Monitoring Irritable Bowel Syndrome and Its Progress. Aliment. Pharmacol. Ther. 1997, 11, 395–402. [CrossRef] y g 37. The National Institute of Statistics and Economic Studies Définition—Unité de Consommation|In //www.insee.fr/fr/metadonnees/definition/c1802 (accessed on 21 May 2019). 38. Vergnaud, A.-C.; Touvier, M.; Méjean, C.; Kesse-Guyot, E.; Pollet, C.; Malon, A.; Castetbon, K.; Hercberg, S. Agreement between Web-Based and Paper Versions of a Socio-Demographic Questionnaire in the NutriNet-Santé Study. Int. J. Public Health 2011, 56, 407–417. [CrossRef] [PubMed] 12 of 13 12 of 13 Nutrients 2021, 13, 4513 39. Touvier, M.; Méjean, C.; Kesse-Guyot, E.; Pollet, C.; Malon, A.; Castetbon, K.; Hercberg, S. Comparison between Web-Based and Paper Versions of a Self-Administered Anthropometric Questionnaire. Eur. J. Epidemiol. 2010, 25, 287–296. [CrossRef] p p J p [ ] 40. Lassale, C.; Péneau, S.; Touvier, M.; Julia, C.; Galan, P.; Hercberg, S.; Kesse-Guyot, E. Validity of Web-Based Self-Reported Weight and Height: Results of the Nutrinet-Santé Study. J. Med. Internet Res. 2013, 15, e152. [CrossRef] [PubMed] p p p 40. Lassale, C.; Péneau, S.; Touvier, M.; Julia, C.; Galan, P.; Hercberg, S.; Kesse-Guyot, E. Validity of Web-Based Self-Reported Weight 40. Lassale, C.; Péneau, S.; Touvier, M.; Julia, C.; Galan, P.; Hercberg, S.; Kesse-Guyot, E. Validity of Web-Ba and Height: Results of the Nutrinet-Santé Study. J. Med. Internet Res. 2013, 15, e152. [CrossRef] [PubM g y y Height: Results of the Nutrinet-Santé Study. J. Med. Internet Res. 2013, 15, e152. [CrossRef] [PubMed] 41. Craig, C.L.; Marshall, A.L.; Sjöström, M.; Bauman, A.E.; Booth, M.L.; Ainsworth, B.E.; Pratt, M.; Ekelund, U.; Yngve, A.; Sallis, J.F.; et al. International Physical Activity Questionnaire: 12-Country Reliability and Validity. Med. Sci. Sports Exerc. 2003, 35, 1381–1395. [CrossRef] 42. Buscail, C.; Sabate, J.-M.; Bouchoucha, M.; Kesse-Guyot, E.; Hercberg, S.; Benamouzig, R.; Julia, C. Western Dietary Pattern Is Associated with Irritable Bowel Syndrome in the French NutriNet Cohort. Nutrients 2017, 9, 986. [CrossRef] [PubMed] 42. Buscail, C.; Sabate, J.-M.; Bouchoucha, M.; Kesse-Guyot, E.; Hercberg, S.; Benamouzig, R.; Julia, C. Western Dietary Pattern Is Associated with Irritable Bowel Syndrome in the French NutriNet Cohort. Nutrients 2017, 9, 986. [CrossRef] [PubMed] 43. Allès, B.; Péneau, S.; Kesse-Guyot, E.; Baudry, J.; Hercberg, S.; Méjean, C. Food Choice Motives Including Sustainability during y 43. References [CrossRef] [PubMed] 13 of 13 13 of 13 Nutrients 2021, 13, 4513 62. Duboc, H.; Dior, M.; Coffin, B. Le syndrome de l’intestin irritable: Nouvelles pistes physiopathologiques et conséquences pratiques. La Revue de Médecine Interne 2016, 37, 536–543. [CrossRef] p q 63. Austin, G.L.; Dalton, C.B.; Hu, Y.; Morris, C.B.; Hankins, J.; Weinland, S.R.; Westman, E.C.; Yancy, W.S.; Drossman, D.A. A Very Low-Carbohydrate Diet Improves Symptoms and Quality of Life in Diarrhea-Predominant Irritable Bowel Syndrome. Clin. Gastroenterol. Hepatol. 2009, 7, 706–708.e1. [CrossRef] p 64. Murray, K.; Wilkinson-Smith, V.; Hoad, C.; Costigan, C.; Cox, E.; Lam, C.; Marciani, L.; Gowland, P.; Spiller, R.C. Differential Effects of FODMAPs (Fermentable Oligo-, Di-, Mono-Saccharides and Polyols) on Small and Large Intestinal Contents in Healthy Subjects Shown by MRI. Am. J. Gastroenterol. 2014, 109, 110–119. [CrossRef] 65. Gibson, P.R.; Varney, J.E.; Muir, J.G. Diet Therapy for Irritable Bowel Syndrome: Is a Diet Low in FODMAPS Really Similar in Efficacy to Traditional Dietary Advice? Gastroenterology 2016, 150, 1046–1047. [CrossRef] y y gy 66. BMJ Publishing Group Does a Low FODMAP Diet Help IBS? DTB 2015, 53, 93–96. [CrossRef] 67. Camilleri, M.; Acosta, A. Re: Halmos et al, A Diet Low in FODMAPs Reduces Symptoms of Irritable Bowel Syndrome. Gastroenterology 2014, 146, 1829–1830. [CrossRef] [PubMed] gy 68. Catassi, G.; Lionetti, E.; Gatti, S.; Catassi, C. The Low FODMAP Diet: Many Question Marks for a Catchy Acronym. Nutrients 2017, 9, 292. [CrossRef] [PubMed] 69. Goldstein, R.; Braverman, D.; Stankiewicz, H. Carbohydrate Malabsorption and the Effect of Dietary Irritable Bowel Syndrome and Functional Bowel Complaints. Isr. Med. Assoc. J. 2000, 2, 583–587. 70. Simrén, M.; Månsson, A.; Langkilde, A.M.; Svedlund, J.; Abrahamsson, H.; Bengtsson, U.; Björnsson, E.S. Food-Related Gastrointestinal Symptoms in the Irritable Bowel Syndrome. Digestion 2001, 63, 108–115. [CrossRef] [PubMed] y p y g 71. Öhman, L.; Simrén, M. New Insights into the Pathogenesis and Pathophysiology of Irritable Bowel Syndrome. Dig. Liver Dis. 2007, 39, 201–215. [CrossRef] 72. Palsson, O.S.; Whitehead, W.E.; Van Tilburg, M.A.L.; Chang, L.; Chey, W.; Crowell, M.D.; Keefer, L.; Lembo, A.J.; Parkman, H.P.; Rao, S.S.C.; et al. Development and Validation of the Rome IV Diagnostic Questionnaire for Adults. Gastroenterology 2016, 150, 1481–1491. [CrossRef] 73. Vork, L.; Weerts, Z.Z.R.M.; Mujagic, Z.; Kruimel, J.W.; Hesselink, M.A.M.; Muris, J.W.M.; Keszthelyi, D.; Jonkers, D.M.A.E.; Masclee, A.A.M. Rome III vs Rome IV Criteria for Irritable Bowel Syndrome: A Comparison of Clinical Characteristics in a Large Cohort Study. Neurogastroenterol. Motil. References Presence of Fermentable Oligo-, Di-, Monosaccharides, and Polyols (FODMAPs) in Commonly Eaten Foods: Extension of a Database to Indicate Dietary FODMAP Content and Calculation of Intake in the General Population from Food Diary Data. BMC Nutr. 2020, 6, 47. [CrossRef] 53. Bennet, S.M.P.; Böhn, L.; Störsrud, S.; Liljebo, T.; Collin, L.; Lindfors, P.; Törnblom, H.; Öhman, L.; Simrén, M. Multivariate Modelling of Faecal Bacterial Profiles of Patients with IBS Predicts Responsiveness to a Diet Low in FODMAPs. Gut 2018, 67, 872–881. [CrossRef] [ ] 54. Major, G.; Pritchard, S.; Murray, K.; Alappadan, J.P.; Hoad, C.L.; Marciani, L.; Gowland, P.; Spiller, R. Colon Hypersensitivity to Distension, Rather Than Excessive Gas Production, Produces Carbohydrate-Related Symptoms in Individuals with Irritable Bowel Syndrome. Gastroenterology 2017, 152, 124–133.e2. [CrossRef] y gy 55. Mansueto, P.; Seidita, A.; D’Alcamo, A.; Carroccio, A. Role of FODMAPs in Patients with Irritable Bowel Syndrome. Nutr. Clin. Pract. 2015, 30, 665–682. [CrossRef] [PubMed] Vandvik, P.O.; Farup, P.G. Perceived Food Intolerance in Subjects with Irritable Bowel Syndrome—Etiology sequences. Eur. J. Clin. Nutr. 2006, 60, 667–672. [CrossRef] 56. Monsbakken, K.W.; Vandvik, P.O.; Farup, P.G. Perceived Food Intolerance in Subjects with Irritable Bo Prevalence and Consequences. Eur. J. Clin. Nutr. 2006, 60, 667–672. [CrossRef] 57. Halpert, A.; Dalton, C.B.; Palsson, O.; Morris, C.; Hu, Y.; Bangdiwala, S.; Hankins, J.; Norton, N.; Drossman, D. What Patients Know about Irritable Bowel Syndrome (IBS) and What They Would like to Know. National Survey on Patient Educational Needs in IBS and Development and Validation of the Patient Educational Needs Questionnaire (PEQ). Am. J. Gastroenterol. 2007, 102, 1972–1982. [CrossRef] [PubMed] 58. Lenhart, A.; Ferch, C.; Shaw, M.; Chey, W.D. Use of Dietary Management in Irritable Bowel Syndrome: Results of a Survey of Over 1500 United States Gastroenterologists. J. Neurogastroenterol. Motil. 2018, 24, 437–451. [CrossRef] [PubMed] 59. Gibson, P.R.; Varney, J.; Malakar, S.; Muir, J.G. Food Components and Irritable Bowel Syndrome. Gastroenterology 2015, 148, 1158–1174.e4. [CrossRef] 60. Halpert, A.; Dalton, C.B.; Palsson, O.; Morris, C.; Hu, Y.; Bangdiwala, S.; Hankins, J.; Norton, N.; Drossman, D.A. Patient Educational Media Preferences for Information about Irritable Bowel Syndrome (IBS). Dig. Dis. Sci. 2008, 53, 3184–3190. [CrossRef] 61. Melchior, C.; Fremaux, S.; Jouët, P.; Macaigne, G.; Raynaud, J.-J.; Facon, S.; Iglicki, F.; Taes, Y.; Sabate, J.-M. Perceived Gastrointesti- nal Symptoms and Association with Meals in a French Cohort of Patients With Irritable Bowel Syndrome. J. Neurogastroenterol. Motil. 2021, 27, 574–580. References 2018, 30, e13189. [CrossRef] y 74. Bai, T.; Xia, J.; Jiang, Y.; Cao, H.; Zhao, Y.; Zhang, L.; Wang, H.; Song, J.; Hou, X. Comparison of the R for IBS Diagnosis: A Cross-Sectional Survey. J. Gastroenterol. Hepatol. 2017, 32, 1018–1025. [CrossRe 75. Aziz, I.; Törnblom, H.; Palsson, O.S.; Whitehead, W.E.; Simrén, M. How the Change in IBS Criteria from Rome III to Rome IV Impacts on Clinical Characteristics and Key Pathophysiological Factors. Am. J. Gastroenterol. 2018, 113, 1017–1025. [CrossRef] [PubMed]
https://openalex.org/W4281629346
https://zenodo.org/record/6636315/files/Tafakkur%20manzili-2022%20-1MAY-2-qism%20%286%29-235-237.pdf
English
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IMPORTANCE OF LANGUAGE IN WRITING FOR NEWSPAPERS
Zenodo (CERN European Organization for Nuclear Research)
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IMPORTANCE OF LANGUAGE IN WRITING FOR NEWSPAPERS IMPORTANCE OF LANGUAGE IN WRITING FOR NEWSPAPERS O'zbekiston Davlat Jahon tillari Universiteti, Madaniyatlararo kommunikatsiyalarning lingvistik ta'minoti yo'nalishi 221-A guruh magistranti Xasanova Mashhura Mirjamolovna O'zbekiston Davlat Jahon tillari Universiteti, Madaniyatlararo kommunikatsiyalarning lingvistik ta'minoti yo'nalishi 221-A guruh magistranti Xasanova Mashhura Mirjamolovna This article is about a number specific characteristic of the language which is used for printed media. It is given very important points of used language and given some suggestions for young journalists. Key words: language, journalism, mass media, journalistic language, media language. g g j j g g g g Language is especially important in journalism. Language is involved with the precise presentation of words and phrases in writing. It contains abbreviations, it li ti di d th i t d l f t Language is especially important in journalism. Language is involved with the precise presentation of words and phrases in writing. It contains abbreviations, capitalization, compounding, and other printed language features. The language used in journalism to present the most recent and up-to-date facts to the public in the simplest, easiest, and most unbiased manner is referred to as journalistic language. Journalism is a crucial kind of communication in which we spread news, information, and knowledge to a wide number of people. It is vital to employ straightforward and basic language for this goal. That is why it is also known as people's language and mass communication language. Here is given some important characteristics of journalistic language. capitalization, compounding, and other printed language features.  Simple and Easy- simple and easy language is required for journalism since the main objective of journalism is to enlighten the general public, literate and illiterate alike, which cannot be accomplished without simple and easy language, which is also a key quality of journalistic language.  Unbiased- in journalistic language, we impart knowledge and send data without any expression or personal sentiments; for example, news on television is delivered without the newscaster's own perspective (who reads the news in news bulletin) Reporters at newspapers do not include their sentiments and feelings when writing a report on an incident.  Brevity- Brevity denotes "shortness." We compose news and reports in journalistic style to be succinct and to the point, with no extraneous information.  Broadness-the broadness of journalistic language distinguishes it from other languages. This indicates that journalistic language may describe all themes and their difficulties, whether they are social, religious, political, or educational. As we can see in newspapers, newspapers cover all themes like as political, social, religious, showbiz, criminal, business, and so on, but other languages just cover a subset of their concerns.  Seriousness-unlike in literary language, facts are expressed in journalistic language in a serious manner.  Awareness- the primary goal of reporting language is to transmit and impart knowledge and information to a big group of individuals in their current state. As a result, the quality of reporting language raises public awareness and encourages individuals to address their own issues.  Communication Area-because journalistic language is intended for the entire public, it has a limitless communication area. As a result, it is straightforward and easy to grasp for the general public.  Objectivity- to be objective, explain an event or item "as it is," without embellishment or extraneous details. This is also an essential aspect of journalistic language.  Media Language- journalistic language is intended for the general public. Mass communication, on the other hand, refers to communicating with a huge number of individuals. In summary, journalistic language is an essential source of mass communication, which is why it is referred to as the language of media  Realism-realism refers to genuineness and actuality. Things are reported in a realistic manner in journalistic terminology.  Realism-realism refers to genuineness and actuality. Things are reported in a realistic manner in journalistic terminology.  Journalistic language represents all social classes. It also reflects all sorts of individuals because newspapers are read by people of different socioeconomic backgrounds.  Politeness- in journalism, politeness of language is required in order to catch the attention of the general public. Otherwise, people would not pay attention to complex words.  Grammar-correct grammar usage is essential in journalistic language; otherwise, it will leave a negative impression on readers. Proper and accurate use of tenses such as past, present, and future is also essential. 236  Avoid Difficult and Unfamiliar Words- we do not employ complicated and new words in journalistic language for public comprehension.  Avoid Difficult Terms- journalism requires plain and straightforward language. And a journalist takes care of this element by using simple language and avoiding difficult phrases while producing a report since he or she realizes that the report is for everyone, not just one group, so he or she transforms sophisticated and tough terminology into simple ones.  Short Phrases- because it is intended for everyone, journalistic language is built on short and simple sentences. To sum up, the language used to present the most recent and up-to-date facts to the public in the simplest, easiest, and most unbiased manner is referred to as journalistic language. Language is involved with the precise presentation of words and phrases in writing. Journalism is a crucial kind of communication in which we spread news, information, and knowledge to a wide number of people. LIST OF REFERENCES: 1. H.D. Zavala González, The importance of journalistic language features and functions in print media, 2010 2. Galperin, I. R. Stylistics, Moscow: Higher School, 1981 1. H.D. Zavala González, The importance of journalistic language features and functions in print media, 2010 2 l l i h S h l 1981 1. H.D. Zavala González, The importance of journalistic language features and functions in print media, 2010 2. Galperin, I. R. Stylistics, Moscow: Higher School, 1981 functions in print media, 2010 2. Galperin, I. R. Stylistics, Moscow: Higher School, 1981 p 2. Galperin, I. R. Stylistics, Moscow: Higher School, 1981 3. https://dailyasianage.com 3. https://dailyasianage.com 4. https://writingcenter.uagc.edu/journalistic-writing
https://openalex.org/W2091209687
https://ccforum.biomedcentral.com/track/pdf/10.1186/cc5325
English
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The influence of cycling-off criteria and pressure support slope on the respiratory and hemodynamic variables in intensive care unit patients
Critical care
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P1 cells with sodium sulfide (60–300 µM) reduced the loss of cell viability elicited by the nitric oxide donor compound (3 mM) or by peroxynitrite (3 mM), as measured by the MTT method. Sodium sulfide did not affect cell viability in the concentration range tested. In mice subjected to bacterial lipopolysaccharide (LPS, 5 mg/kg i.p.), treatment of the animals with sodium sulfide (0.2 mg/kg/hour for 4 hours, administered in Alzet minipumps) reduced the LPS- induced increase in plasma IL-1β and TNFα levels. These responses were attenuated when animals were pretreated with the heme oxygenase inhibitor tin-protoporphyrin IX (6 mg/kg). The current results point to the cytoprotective and anti-inflammatory effects of hydrogen sulfide, in cells exposed to nitrosative stress, and in animals subjected to endotoxemia. cells with sodium sulfide (60–300 µM) reduced the loss of cell viability elicited by the nitric oxide donor compound (3 mM) or by peroxynitrite (3 mM), as measured by the MTT method. Sodium sulfide did not affect cell viability in the concentration range tested. In mice subjected to bacterial lipopolysaccharide (LPS, 5 mg/kg i.p.), treatment of the animals with sodium sulfide (0.2 mg/kg/hour for 4 hours, administered in Alzet minipumps) reduced the LPS- induced increase in plasma IL-1β and TNFα levels. These responses were attenuated when animals were pretreated with the heme oxygenase inhibitor tin-protoporphyrin IX (6 mg/kg). The current results point to the cytoprotective and anti-inflammatory effects of hydrogen sulfide, in cells exposed to nitrosative stress, and in animals subjected to endotoxemia. Infusion of sodium sulfide improves myocardial and endothelial function in a canine model of cardiopulmonary bypass C Szabó1, G Veres2, T Radovits2, M Karck2, G Szabó2 1Ikaria Inc., Seattle, WA, USA; 2University of Heidelberg, Germany Critical Care 2007, 11(Suppl 2):P1 (doi: 10.1186/cc5161) Hydrogen sulfide is produced endogenously by a variety of enzymes involved in cysteine metabolism. Clinical data indicate that endogenous levels of hydrogen sulfide are diminished in various forms of cardiovascular diseases. The aim of the current study was to investigate the effects of hydrogen sulfide supple- mentation on cardiac function during reperfusion in a clinically relevant experimental model of cardiopulmonary bypass. Twelve anesthetized dogs underwent hypothermic cardiopulmonary bypass. After 60 minutes of hypothermic cardiac arrest, reper- fusion was started after application of either saline vehicle (control, n = 6), or the sodium sulfide infusion (1 mg/kg/hour, n = 6). Biventricular hemodynamic variables were measured by combined pressure–volume–conductance catheters. Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 P3 Epithelial cell apoptosis is similar but hypoxic-inducible factor expression is weaker in acute acalculous cholecystitis than in calculous cholecystitis M Vakkala1, J Laurila1, J Saarnio2, V Koivukangas2, H Syrjälä3, T Karttunen4, Y Soini4, T Ala-Kokko1 1Department of Anesthesiology, 2Department of Surgery, 3Department of Infection Control and 4Department of Pathology, Oulu University Hospital, Oulu, Finland Critical Care 2007, 11(Suppl 2):P3 (doi: 10.1186/cc5163) Introduction It has been previously shown that the two forms of acute cholecystitis, acute acalculous cholecystitis (AAC) and acute calculous cholecystitis (ACC), have significantly different histopathological features suggesting that AAC is a manifestation of systemic critical illness whereas ACC is a local disease of the gallbladder. A balance between cell proliferation and cell death is essential for cell homeostasis. The purpose of this study was to compare the markers of apoptosis, cell proliferation, and expression of hypoxic-inducible factor alpha (HIF-1α) in AAC, ACC and normal gallbladders. Methods The AAC group consisted of 30 patients who underwent open cholecystectomy due to acute acalculous cholecystitis during their ICU stay. The ACC group consisted of 21 hospitalized patients who underwent cholecystectomy due to acute calculous cholecystitis. The control group consisted of nine samples taken from normal gallbladders extirpated during pancreatic tumor surgery. The immunohistochemical analysis was done according to the manufacturer’s recommendations and they consisted of Ki-67 (proliferation), M30 (apoptosis) and HIF-1α antibodies. Cell proliferation and degree of apoptosis were expressed as the percentage of positive cells. HIF-1α expression was expressed as absent or weak (Score 1) or strong (Score 2). P2 P2 Cytoprotective and anti-inflammatory effects of hydrogen sulfide in macrophages and mice C Szabo, L Kiss, E Pankotai University of Medicine and Dentistry of New Jersey, Newark, NJ, USA Critical Care 2007, 11(Suppl 2):P2 (doi: 10.1186/cc5162) P1 Coronary and pulmonary blood flow, vasodilator responses to acetylcholine and sodium- nitroprusside and pulmonary function were also determined. Administration of sodium sulfide led to a significantly better recovery of left and right ventricular systolic function (P < 0.05) after 60 minutes of reperfusion. Coronary blood flow was also significantly higher in the sodium sulfide-treated group (P < 0.05). Sodium sulfide treatment improved coronary blood flow, and preserved the acetylcholine-induced increases in coronary and pulmonary blood (P < 0.05). Myocardial ATP levels were markedly improved in the sulfide-treated group. Thus, supplementation of sulfide improves the recovery of myocardial and endothelial function and energetic status after hypothermic cardiac arrest during cardiopulmonary bypass. These beneficial effects occurred without any detectable adverse hemodynamic or cardiovascular effects of sulfide at the dose used in the current study. Critical Care Volume 11 Suppl 2, 2007 27th International Symposium on Intensive Care and Emergency Medicine Brussels, Belgium, 27–30 March 2007 Brussels, Belgium, 27–30 March 2007 Published online: 22 March 2007 These abstracts are available online at http://ccforum.com/supplements/11/S2 © 2007 BioMed Central Ltd Published online: 22 March 2007 These abstracts are available online at http://ccforum.com/supplements/11/S2 © 2007 BioMed Central Ltd Effect of prostaglandin E2 on ATP-induced Ca2+ responses in human THP-1 monocytic cells Effect of prostaglandin E2 on ATP-induced Ca2+ responses in human THP-1 monocytic cells M Goto1, M Murakawa1, J Kimura1, I Matsuoka2 1Fukushima Medical University, Fukusima, Japan; 2Takasaki University of Health and Welfare, Gunma, Japan Critical Care 2007, 11(Suppl 2):P4 (doi: 10.1186/cc5164) Introduction To clarify the relation between ATP and prostaglandin E2 (PGE2) in the immunologic system, we investigated the acute and chronic effects of PGE2 on activation of purinergic signaling in monocytes by measuring the ATP-induced elevation of intracellular Ca2+ ([Ca]i) in fura-2-loaded THP-1 monocytes. Method THP-1 monocytes were grown for about 2 days. To examine the chronic effects, PGE2 and dibutyryl cAMP (dbcAMP) were added and incubated for another day. The cell suspensions were washed, loaded with fura-2-AM, and transferred into a quartz cuvette and placed in the thermostat-regulated sample chamber of a dual excitation beam spectrophotometer. To examine the acute effects, ATP was added immediately after PGE2 and dbcAMP into the cuvette. In the chronic experiment, ATP alone was added into the cuvette. Fura-2 fluorescence emission was measured at 510 nm. The [Ca]i was calculated from the ratio of the fluorescence at the two excitation wavelengths. sepsis [1]. IFNγ plays a critical role in host defense by promoting Th1 phenotype and bacterial clearance. Low IFNγ levels are associated with the Th2 phenotype consistent with critical illness anergy [2]. It has been reported that 100 and 300 mM ATP increased LPS/PHA-stimulated IL-10 secretion in human blood [3]. Higher IL-10/IFNγ ratio shifts the immune phenotype from Th1 to Th2 response. We studied the effect of ATP on LPS-stimulated IL-10 and IFNγ secretion in a standardized ex-vivo whole human blood culture. Methods Venous blood from 10 healthy volunteers was drawn into tubes containing 10 ng LPS/ml (ILCSÒ; EDI GmBH, Reutlingen, Germany) and incubated with or without 100 mM ATP, respectively, at 37°C for 24 hours. The supernates were separated and frozen at –20°C. Cytokine levels were analysed on a robotic workstation (epMotion 5075; Eppendorf AG, Hamburg, Germany) in duplicate using the ELISA Cytokine kit (Luminex; Biosource Int., Camarillo, CA, USA). Results ATP induced a transient increase in [Ca]i followed by a sustained elevation of [Ca]i. Acutely, PGE2 inhibited both the transient and sustained ATP-induced elevations of [Ca]i. However, this acute inhibitory effect diminished gradually with time and chronic PGE2 accelerated the transient and sustained ATP- induced [Ca]i elevations for 24 hours. Cytoprotective and anti-inflammatory effects of hydrogen sulfide in macrophages and mice Cytoprotective and anti-inflammatory effects of hydrogen sulfide in macrophages and mice C Szabo, L Kiss, E Pankotai University of Medicine and Dentistry of New Jersey, Newark, NJ, USA Critical Care 2007, 11(Suppl 2):P2 (doi: 10.1186/cc5162) The aim of the current study was to test potential cytoprotective and anti-inflammatory effects of the novel biological mediator hydrogen sulfide in murine models. Murine J774 macrophages were grown in culture and exposed to cytotoxic concentrations of nitrosoglutathione, or peroxynitrite (a reactive species formed from the reaction of nitric oxide and superoxide). Pretreatment of the Results Apoptosis (median, 25th, 75th percentiles) was significantly increased in AAC 1.3% (1.0%, 3.3%), P = 0.001 and ACC 0.93% (0.40%, 3.25%), P = 0.011 compared with controls 0.32% (0.20%, 0.40%). Proliferation rate was also significantly increased in AAC S1 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine Figure 1 (abstract P5) Figure 1 (abstract P5) Figure 1 (abstract P5) 8.0% (4.0%, 17.0%), P < 0.001 and ACC 14% (7.5%, 26.5%), P = 0.001 compared with controls 1.0% (1.0%, 3.0%). Strong HIF- 1α staining was observed in 100% of ACC, in 57% of AAC and in 44% of control specimens (P < 0.001). Strong HIF-1α expression was associated with increased cell proliferation (P = 0.002). Conclusions Cell proliferation and apoptosis were increased in AAC and ACC. The expression of hypoxic-inducible factor was, however, stronger in ACC compared with AAC. Effect of prostaglandin E2 on ATP-induced Ca2+ responses in human THP-1 monocytic cells Both the acute and chronic effects of PGE2 were mimicked by dbcAMP. In Ca2+-free solution, ATP did not induce the sustained elevation of [Ca]i in control cells or cells pretreated for 24 hours with dbcAMP. This indicates that the ATP-induced sustained elevation of [Ca]i was due to Ca2+ entry. In addition, receptor-operated Ca2+ channel blockers inhibited the sustained ATP-induced elevation of [Ca]i in control cells and cells pretreated with for 24 hours dbcAMP. Results Added ATP reduced the mean concentration of IFNγ in LPS- stimulated blood from 1,206 ± 1,667 pg/ml to 140 ± 128 pg/ml; P = 0.006. There was no consistent effect of ATP on IL-10 secretion in our study (21.6 ± 16.9 pg/ml to 17.2 ± 18.8 pg/ml). Interestingly, three subjects of Indian/Indonesian origin had IL-10 levels below the assay detection limit. The mean IL-10/IFNγ ratio was increased from 0.05 ± 0.04 to 0.16 ± 0.09 in the remaining Caucasian subjects (P = 0.015). See Figure 1. Conclusion Acute PGE2 inhibited the ATP-induced activation of monocytes. On the other hand, chronic PGE2 accelerated monocyte activation by upregulation of receptor-operated Ca2+ channels (ROCs). If this mechanism exhibits a physiological role, ROC inhibitors should be developed as new anti-inflammatory agents. Conclusions Our results suggest an immunosuppressive effect of extracellular ATP that is evident by the decrease of IFNγ and therefore the relative shift of the immune response towards Th2 phenotype. Although this may represent a self-protective mechanism, it may contribute to critical illness anergy. References Introduction Extracellular release of ATP is an important modulator of immune response. ATP plasma concentration is increased in M Nalos1, S Huang1, A Khan2, A McLean1 1Nepean Hospital, Penrith, Australia; 2Macquarie University, North Ryde, Australia Critical Care 2007, 11(Suppl 2):P5 (doi: 10.1186/cc5165) Available online http://ccforum.com/supplements/11/S2 P6 Methods We enrolled 30 patients with septic shock requiring invasive hemodynamic monitoring and norepinephrine infusion ≥ 0.5 µg/kg/min to maintain MAP between 65 and 75 mmHg. Patients were randomized to receive either 10, 20, or 30 mg enteral glibenclamide. Systemic hemodynamics, global oxygen transport, arterial lactate concentrations, gas exchange, and plasma glucose concentrations were determined at baseline, and following 3, 6 and 12 hours after administration of the study drug. Methods We enrolled 30 patients with septic shock requiring invasive hemodynamic monitoring and norepinephrine infusion ≥ 0.5 µg/kg/min to maintain MAP between 65 and 75 mmHg. Patients were randomized to receive either 10, 20, or 30 mg enteral glibenclamide. Systemic hemodynamics, global oxygen transport, arterial lactate concentrations, gas exchange, and plasma glucose concentrations were determined at baseline, and following 3, 6 and 12 hours after administration of the study drug. Results Glibenclamide decreased plasma glucose concentrations in a dose-dependent manner, but failed to reduce norepinephrine requirements. None of the doses had any effects on cardiopulmonary hemodynamics. See Table 1. Tyrosine phosphorylation modulates rat vascular response to experimental endotoxemia in vivo and in vitro Tyrosine phosphorylation modulates rat vascular response to experimental endotoxemia in vivo and in vitro C Lehmann, T Hammann, O Adamek, H Erber, M Manthey, T Wenzel, A Stier, M Wendt, D Pavlovic Ernst-Moritz-Arndt-Universität Greifswald, Germany Critical Care 2007, 11(Suppl 2):P6 (doi: 10.1186/cc5166) Results Glibenclamide decreased plasma glucose concentrations in a dose-dependent manner, but failed to reduce norepinephrine requirements. None of the doses had any effects on cardiopulmonary hemodynamics. See Table 1. Introduction Endotoxemia is characterized by vascular hypo- reactivity, hypotension and microcirculatory changes that are partially linked to the excess of nitric oxide production. The agents that can influence Ca2+ transport (affect Ca-ATPase) or modulate Ca2+ sensitivity of the smooth muscle contraction (modulate phos- phorylation) may theoretically influence some of the above- mentioned effects. Table 1 (abstract P7) Plasma glucose concentration (mg/dl) Time Glibenclamide 0 hours 3 hours 6 hours 12 hours 10 mg 118 ± 13 110 ± 9 109 ± 10 107 ± 10 20 mg 117 ± 5 106 ± 4 93 ± 7* 98 ± 9* 30 mg 113 ± 6 86 ± 3* 89 ± 4* 98 ± 3* Data presented as mean ± SEM. *P < 0.05 vs baseline (0 hours) within groups. Table 1 (abstract P7) Plasma glucose concentration (mg/dl) Methods We evaluated the effects of tyrosine phosphatase or kinase inhibitors, sodium orthovanadate (SOV) or genistein (GEN). The effects of these agents were examined in vitro, in a model of vascular hyporeactivity of sepsis, in rings of rat aorta (RA), with or without endothelium (±ENDO), or in human mesenteric artery (HMA). In vivo, the intestinal microcirculation (terminal ileum) of endotoxemic rats (LEW.1A) that received i.v. lipopolysaccharide (LPS), 15 mg/kg BW, was examined using intravital microscopy. g g g py Results In vitro. The nitric oxide production inhibitor L-NAME (5 × 10–4) and cGMP inhibitor ODQ (5 x 10–5) abolished LPS- induced hyporeactivity. GEN attenuated maximal tension (Tmax) while SOV increased the response to PE; Tmax (kg/g, dry muscle): controls vs SOV, RA (–ENDO): 0.87 ± 0.19 vs 1.42 ± 0.23 (10–7); 1.56 ± 0.28 (10–6) and 2.33 ± 0.69 (10–5); RA (+ENDO): 0.88 ± 0.21 vs 1.53 ± 0.35 (10–7); 1.35 ± 0.30 (10–6) and 2.55 ± 0.68 (10–5); and HMA (+ENDO): 1.12 ± 0.23 vs 0.37 ± 0.14 (10–7); 2.06 ± 0.21 (10–6) and 3.00 ± 0.07 (10–5). Conclusion Oral glibenclamide is an ineffective adjunct in the treatment of catecholamine-dependent human septic shock. Molecular mechanism of glutamine induction of HSP70 involves activation of the O-linked-N-acetylglucosamine pathway in murine embryonic fibroblast cells Molecular mechanism of glutamine induction of HSP70 involves activation of the O-linked-N-acetylglucosamine pathway in murine embryonic fibroblast cells C Hamiel1, S Pinto2, K Singleton1, P Wischmeyer1 1University of Colorado, Denver, CO, USA; 2Valparaiso University, IN, USA Critical Care 2007, 11(Suppl 2):P8 (doi: 10.1186/cc5168) In vivo. In the LPS group GEN increased mucosal functional capillary density (FCD, cm/cm2; mean ± SD; LPS vs GEN, 105.5 ± 44.6 vs 174.7 ± 39.1; P = 0.018). SOV (7.5 mg/kg) increased FCD not only in mucosa (163.7 ± 40.0; P = 0.024) but also in the longitudinal muscular layer (LPS vs SOV, 111.9 ± 24.0 vs 172.2 ± 19.5; P < 0.001). Surprisingly, the SOV (15 mg/kg) alone (without LPS) increased leukocyte sticking in the venules V1 (LPS vs SOV, number of stickers/mm2, 403.3 ± 113.9 vs 669.8 ± 150.8; P = 0.027). Introduction The purpose of this study was to determine whether glutamine (GLN)-mediated cellular protection is dependent on the O-linked-N-acetylglucosamine (O-glcNAc) pathway. GLN can protect against critical illness via induction of HSP70. The molecular mechanism by which GLN enhances HSP70 is unknown. GLN can increase flux through the hexosamine biosynthetic pathway and activate transcription factors by O-glcNAc. We investigated GLN’s effect on O-glcNAc levels and nuclear translocation of SP1 and HSF-1, which are vital to HSP70 expression. To determine the importance of O-glcNAc, we used silencing RNA (siRNA) against O- linked-N-acetylglucosamine transferase (OGT), the enzyme that catalyzes addition of O-glcNAc to proteins. Conclusions The tyrosine phosphorylation pathway may play an important role in modulation of the LPS-induced vascular hyporeactivity and could enhance terminal ileum microcirculation. This might be a result of both modulation of tyrosine phosphorylation by genistein and sodium orthovanadate, and/or plasma membrane Ca-ATPase inhibition by SOV. P7 Methods Mouse embryonic fibroblast cells were treated with 0 mM GLN (CT) or 10 mM GLN (GLN), heat stressed (HS) and allowed to recover for 20 minutes. Cells were stained and mean fluorescent intensities (MFIs) measured for total O-glcNAc and nuclear HSF-1 and SP1. For OGT silencing, cells were transfected with either no siRNA, siRNA to OGT, or negative control oligos (nc siRNA) and then treated as above (but with 4 hours recovery). HSP70 and OGT were evaluated by western blot. References Interferon gamma levels are reduced by adenosine 5′-triphosphate in lipopolysaccharide-stimulated whole human blood 1. Bours MJ, Swennen EL, Di Virgilio F, et al.: Adenosine 5′- triphosphate and adenosine as endogenous signaling molecules in immunity and inflammation. Pharmacol Ther 2006, 112:358-404. 1. Bours MJ, Swennen EL, Di Virgilio F, et al.: Adenosine 5′- triphosphate and adenosine as endogenous signaling molecules in immunity and inflammation. Pharmacol Ther 2006, 112:358-404. M Nalos1, S Huang1, A Khan2, A McLean1 1Nepean Hospital, Penrith, Australia; 2Macquarie University, North Ryde, Australia Critical Care 2007, 11(Suppl 2):P5 (doi: 10.1186/cc5165) 2. Ertel W, Keel M, Neidhardt R, et al.: Inhibition of the defence system stimulating interleukin-12 interferon-gamma pathway during critical illness. Blood 1997, 89:1612-1620. 3. Swennen EL, Bast A, Dagnelie PC: Immunoregulatory effects of adenosine 5′-triphosphate on cytokine release from stimulated whole blood. Eur J Immunol 2005, 35:852-858. Introduction Extracellular release of ATP is an important modulator of immune response. ATP plasma concentration is increased in S2 Available online http://ccforum.com/supplements/11/S2 Glibenclamide dose response in patients with septic shock A Morelli1, C Ertmer2, M Lange2, K Broeking2, H Van Aken2, A Orecchioni1, M Rocco1, P Pietropaoli1, M Westphal2 1University of Rome ‘La Sapienza’, Rome, Italy; 2University Hospital of Muenster, Germany Critical Care 2007, 11(Suppl 2):P7 (doi: 10.1186/cc5167) Results Microscopy showed GLN treatment increased nuclear MFI for HSF-1 by 40% (HS-CT: 1,005 ± 146 vs HS- GLN:1403 ± 102, P < 0.05) and SP1 by 54% (HS-CT: 214 ± 14 vs HS-GLN: 330 ± 13, P < 0.05). Total O-glcNAc levels showed 44% MFI increase in HS-GLN compared with HS-CT (HS-CT: 360 ± 24 vs HS-GLN: 518 ± 51, P < 0.05). Following OGT silencing, HS-GLN showed a threefold increase in HSP70 Introduction (K+ATP) channels are implicated in the pathophysiology of catecholamine tachyphylaxis in septic shock. This prospective, randomized, double-blinded, clinical study was designed to determine whether different doses of glibenclamide have any effects on norepinephrine requirements and cardio- pulmonary hemodynamics in patients with septic shock. Introduction (K+ATP) channels are implicated in the pathophysiology of catecholamine tachyphylaxis in septic shock. This prospective, randomized, double-blinded, clinical study was designed to determine whether different doses of glibenclamide have any effects on norepinephrine requirements and cardio- pulmonary hemodynamics in patients with septic shock. S3 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin (P = 0.04). These increases were completely blocked by OGT silencing (P = 0.02 vs non-siRNA GLN groups). GLN-nc siRNA groups did not decrease in HSP70 production. OGT was knocked down 86% compared with controls (siRNA: 0.999 ± 0.19 vs CT: 0.131 ± 0.05). N = 3. (P = 0.04). These increases were completely blocked by OGT silencing (P = 0.02 vs non-siRNA GLN groups). GLN-nc siRNA groups did not decrease in HSP70 production. OGT was knocked down 86% compared with controls (siRNA: 0.999 ± 0.19 vs CT: 0.131 ± 0.05). N = 3. vasodilatory peptide hormone with anti-inflammatory properties, may improve the oxygen delivery–demand relationship, thereby limiting the increase in arterial lactate concentrations in ovine endo- toxemia. Methods Fourteen adult ewes were instrumented for chronic hemo- dynamic monitoring. Following 16 hours of endotoxemia (Salmonella typhosa endotoxin, 10 ng/kg/min) the animals received either a continuous infusion of AM at incremental doses (10, 50, 100 ng/kg/min; each for 30 min) or the vehicle (normal saline; n = 7 each). The effects of N-acetylcysteine on the levels of glutathione, serum TNFα, and tissue malondialdehyde in sepsis The effects of N-acetylcysteine on the levels of glutathione, serum TNFα, and tissue malondialdehyde in sepsis M Gul, M Ayan, A Seydanoglu, B Cander, S Girisgin, I Erayman Selcuk University Meram Medical School, Konya, Turkey Critical Care 2007, 11(Suppl 2):P9 (doi: 10.1186/cc5169) Objectives This study was designed to determine the effects of N- acetylcysteine (NAC) as an antioxidant agent on the free oxygen radicals and their plasma levels. Conclusions Despite decreasing MAP, infusion of AM reversed pulmonary hypertension and improved the oxygen supply–demand relationship in a dose-dependent manner, as indicated by a reduced arterial lactate concentration. However, due to the vasodilatory properties of AM, it may be rationale to combine AM with a vasopressor agent. Methods In this study, 40 Sprague–Dawley rats were randomly divided into three groups as sham (n = 10), sepsis (n = 10), and sepsis + NAC (20 mg/kg/24 hours) (n = 10). An experimental sepsis model was performed by a cecal ligation and perforation (CLP). NAC was administered at 0, 8 and 16 hours after CLP. The blood samples were taken at 24 hours to determine the levels of serum TNFα and erythrocyte glutathione (GSH), and renal and liver tissue malondialdehyde (MDA). P11 Results The serum TNFα levels were significantly decreased in group 3 compared with group 2 (P < 0.05). The erythrocyte GSH levels significantly increased in group 3 compared with group 2 (P < 0.05). In group 3, the liver MDA levels were decreased compared with group 2, but not statistically significant (P > 0.05) In group 3, the renal MDA levels were significantly decreased compared with group 2 (P < 0.05). The lung tissue PMNL levels significantly decreased in group 3 compared with group 2 (P < 0.05). Angiopoietin-2 correlates with pulmonary capillary permeability and disease severity in critically ill patients Angiopoietin-2 correlates with pulmonary capillary permeability and disease severity in critically ill patients M van der Heijden1, V van Hinsbergh2, G van Nieuw Amerongen2, P Koolwijk2, R Musters2, J Groeneveld1 1VU University Medical Center, Amsterdam, The Netherlands; 2Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands Critical Care 2007, 11(Suppl 2):P11 (doi: 10.1186/cc5171) Conclusion In an experimental sepsis model, with the administra- tion of NAC as an antioxidant agent at lower doses, many meaning- ful positive effects were detected on the levels of erythrocyte GSH, serum TNFα, respiration function, and renal tissue MDA. In spite of the low dose, NAC therapies decrease the organ function abnor- malities; these effects were not reflected in the histopathological investigations. These findings suggest that NAC could be a possible therapeutic agent for sepsis and its mortality. However, further studies are needed to elucidate the effects of these drugs at higher doses. Introduction It has previously been shown that angiopoietin-1 (Ang1) protects the adult vasculature against plasma leakage, whereas Ang2 and VEGF destabilize the vascular endothelium resulting in vascular leakage. Consequently they might be involved in the pathophysiology of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) in sepsis patients. We hypothesized that plasma Ang2 levels are associated with pulmonary capillary protein permeability, the lung injury score (LIS), length of stay on the ICU, the APACHE II score and survival in septic patients with ALI or ARDS. Glibenclamide dose response in patients with septic shock Conclusions These results show GLN can activate the O-glcNAc pathway and enhance nuclear translocation of HSF-1 and SP1. Inhibition of OGT blocked GLN-mediated induction of HSP70. Thus, it appears the mechanism of GLN-mediated HSP70 expres- sion is dependent on enhanced O-glcNAc pathway activation. Results Endotoxin infusion contributed to a hypotensive– hyperdynamic circulation characterized by decreases in mean arterial pressure (MAP) and systemic vascular resistance index as well as increases in heart rate (HR), cardiac index (CI) and arterial lactate concentrations. AM infusion at 100 ng/kg/min increased the CI (12.2 ± 0.8 vs 7.8 ± 0.5 l/min) and oxygen delivery index (1,734 ± 121 vs 1,075 ± 63 ml/min/m2), thereby decreasing the arterial lactate concentration (0.7 ± 0.2 vs 1.7 ± 0.3 mg/dl) and mean pulmonary arterial pressure (18 ± 1 vs 24 ± 1 mmHg; each P < 0.001 vs control) noticed in the control group. However, AM infusion at 100 ng/kg/min was linked to a decrease in MAP (64 ± 2 vs 80 ± 4 mmHg, P < 0.001 vs control). P12 Dose-dependent effects of octreotide on plasma activities of IL-6 and lung tissue levels of malondialdehyde in sepsis M Gul, A Seydanoglu, M Ayan, B Cander, I Erayman, S Girisgin Selcuk University Meram Medical School, Konya, Turkey Critical Care 2007, 11(Suppl 2):P12 (doi: 10.1186/cc5172) Dose-dependent effects of octreotide on plasma activities of IL-6 and lung tissue levels of malondialdehyde in sepsis M Gul, A Seydanoglu, M Ayan, B Cander, I Erayman, S Girisgin Selcuk University Meram Medical School, Konya, Turkey Critical Care 2007, 11(Suppl 2):P12 (doi: 10.1186/cc5172) Background and aim Sepsis, a complex and rapidly progressing infectious disease with high levels of mortality, is widely regarded as the most challenging problem in intensive care. The lung is frequently the first failing organ during septic conditions. Although the etiology of sepsis is multifactorial, early release of proinflam- matory cytokines and oxidative damage are probably most impor- tant factors that lead to cell damage, organ dysfunction, and death. This study aimed to determine the effects of treatment with octreo- tide (OCT), on plasma activities of IL-6 and tissue levels of malon- dialdehyde (MDA) in an experimental model of sepsis. gene expression analysis (Affymetrix) was applied to serial cardiac biopsies of sham (n = 2) and E. coli infected pigs (n = 3). Methods Cardiac samples were taken basal and hourly after infection for gene analysis and at the end of the experiment for histopathological examination. Genes were determined to be differentially regulated at a greater than or less than twofold change and P < 0.05. gene expression analysis (Affymetrix) was applied to serial cardiac biopsies of sham (n = 2) and E. coli infected pigs (n = 3). Methods Cardiac samples were taken basal and hourly after infection for gene analysis and at the end of the experiment for histopathological examination. Genes were determined to be differentially regulated at a greater than or less than twofold change and P < 0.05. Methods Sepsis was induced in female Sprague–Dawley rats by cecal ligation and puncture (CLP) as previously described. Group 1 (n = 10), sham operated animals; Group 2 (n = 10), sepsis served as control; Group 3 (n = 10) and Group 4 (n = 10), respectively, OCT 50 µg/kg twice a day and OCT 100 µg/kg twice a day administered subcutaneously immediately after the induction of sepsis and at 12 hours. Rats were sacrificed 24 hours after the surgical procedure. P12 Blood and lung tissue samples were taken 24 hours after sepsis induction. Plasma activities of IL-6 and lung tissue levels of MDA were measured. Results Sham pigs had stable heart rate, cardiac output (CO) and core temperature for the 5-hour period; infected pigs demon- strated an early elevation in CO and ventricular shortening and/or ejection (assessed by echocardiography) followed by development of hypodynamics. In infected animals, increasing numbers of genes were upregulated or downregulated (36, 278, 514, 842 and 1,238 at 1, 2, 3, 4 and 5 hours) (Figure 1) whereas sham infection altered fewer (247, 67 and 384 genes at 2, 3 and 4 hours). Comparing sham vs infected animals at the same time, numbers of significantly altered genes increased with time (32 at basal, to 74, 189 and 601 at 2, 3 and 4 hours post infection). In hematoxylin–eosin- stained sections, histopathological assessment revealed acute inflammation in pericardium and myocardium in infected pigs. Results The results showed that the plasma levels of IL-6, an inflammatory indicator, and tissue levels of MDA, an oxidative indicator, are significantly increased during experimental model of sepsis (P < 0.05). Increase in MDA levels and IL-6 activities after CLP-induced sepsis was significantly prevented by OCT (100 µg/kg, s.c.) administration (P < 0.05). Conclusions These results will provide biomarker and mechanistic insights to pathogenesis of cardiac dysfunction of septic peritonitis and may also help identify some altered novel gene transcription pathways that can serve as new targets for diagnostic tools and therapeutic strategies. All candidate genes will be validated by quantitative PCR. Conclusion Octreotide seems to have a dose-dependent antioxidative and immunomodulator effect in CLP-induced sepsis in rats. Further trials are necessary to reveal the therapeutic effect of OCT in sepsis. On the other hand, further studies should be performed aiming to reveal the optimal OCT doses. As a drug with a wide margin of safety and less adverse reaction profile, OCT merits consideration as a choice of treatment in sepsis and septic shock. P10 Methods A prospective observational study was performed in an ICU of an university hospital on 112 patients: 38 after elective cardiac surgery, 26 after major vascular surgery, 24 with sepsis and 24 with trauma. Plasma levels of Ang1, Ang2 and VEGF were measured and a mobile probe system was used to measure the pulmonary leak index (PLI) (that is, the transvascular transport rate of gallium-67-radiolabeled transferrin). Exogenous adrenomedullin reduces the arterial lactate concentration and mean pulmonary arterial pressure in ovine endotoxemia C Ertmer1, M Lange1, H Van Aken1, K Bröking1, S Vocke1, F Daudel1, M Booke2, M Westphal3 1University of Muenster, Germany; 2Hospital of the Main-Taunus-Kreis, Hofheim, Germany; 3UTMB, Galveston, USA Critical Care 2007, 11(Suppl 2):P10 (doi: 10.1186/cc5170) Results Plasma levels of Ang2 and the PLI were significantly higher in patients with sepsis compared with other patient groups. In the sepsis group, a positive linear correlation was observed between plasma levels of Ang2 and length of stay on the ICU (rs = 0.509, P < 0.05) as index for disease severity. For all patients together, Ang2 had a positive linear correlation with PLI (rs = 0.374, P < 0.01), LIS (rs = 0.489, P < 0.01) and APACHE II score (rs = 0.287, P < 0.01). Furthermore, Ang2 was significantly increased Introduction Sepsis-associated arterial hypotension may be complicated by inadequate systemic and regional oxygen delivery resulting in lactic acidosis and multiple organ failure. We hypothe- sized that exogenous administration of adrenomedullin (AM), a Introduction Sepsis-associated arterial hypotension may be complicated by inadequate systemic and regional oxygen delivery resulting in lactic acidosis and multiple organ failure. We hypothe- sized that exogenous administration of adrenomedullin (AM), a S4 Available online http://ccforum.com/supplements/11/S2 Figure 1 (abstract P13) in nonsurvivors. Plasma Ang1 levels did not differ between groups. VEGF levels were undetectable in the plasma of the majority of patients. Conclusions Our results suggest that Ang2 is a mediator of pulmonary capillary permeability and a marker of disease severity in critically ill patients. Furthermore, the plasma levels of Ang2 and the ratio between Ang1 and Ang2 are more important in pulmonary capillary permeability and disease severity than absolute levels of Ang1 and VEGF. P14 Alkaline phosphatase treatment improves renal function in patients with severe sepsis or septic shock P15 associated with proximal tubule injury. In several in vitro and animal studies alkaline phosphatase (AP) was found to be effective in attenuating the inflammatory response by dephosphorylating LPS and may prevent organ damage. The objective of this study was to investigate the effect of AP on renal iNOS expression and kidney damage in patients with severe sepsis or septic shock. associated with proximal tubule injury. In several in vitro and animal studies alkaline phosphatase (AP) was found to be effective in attenuating the inflammatory response by dephosphorylating LPS and may prevent organ damage. The objective of this study was to investigate the effect of AP on renal iNOS expression and kidney damage in patients with severe sepsis or septic shock. P15 Moderate hypothermia attenuates changes in respiratory system mechanics and cytokine production during low lung volume ventilation in rats P Dostal1, M Senkerik1, V Cerny1, R Parizkova1, J Suchankova1, D Kodejskova1, D Bares1, P Zivny1, H Zivna2 1University Hospital Hradec Kralove, Czech Republic; 2Charles University in Prague, Faculty of Medicine Hradec Kralove, Czech Republic Critical Care 2007, 11(Suppl 2):P15 (doi: 10.1186/cc5175) P15 Moderate hypothermia attenuates changes in respiratory system mechanics and cytokine production during low lung volume ventilation in rats P Dostal1, M Senkerik1, V Cerny1, R Parizkova1, J Suchankova1, D Kodejskova1, D Bares1, P Zivny1, H Zivna2 1University Hospital Hradec Kralove, Czech Republic; 2Charles University in Prague, Faculty of Medicine Hradec Kralove, Czech Republic Critical Care 2007, 11(Suppl 2):P15 (doi: 10.1186/cc5175) Moderate hypothermia attenuates changes in respiratory system mechanics and cytokine production during low lung volume ventilation in rats P Dostal1, M Senkerik1, V Cerny1, R Parizkova1, J Suchankova1, D Kodejskova1, D Bares1, P Zivny1, H Zivna2 1University Hospital Hradec Kralove, Czech Republic; 2Charles University in Prague, Faculty of Medicine Hradec Kralove, Czech Republic Critical Care 2007, 11(Suppl 2):P15 (doi: 10.1186/cc5175) Fifteen patients (nine male/six female, age 55 ± 5 years) with Gram-negative bacterial infection, two out of four SIRS criteria (<24 hours) and acute onset of end-organ dysfunction (<12 hours) were included in a randomized, double-blind, placebo-controlled phase IIa study (2:1 ratio). An intravenous bolus injection of 67.5 U/kg bovine intestinal AP was followed by a maintenance dose of 177.5 U/kg for 24 hours. Arterial blood and urine were collected at different time points and analyzed for stable metabo- lites of NO. iNOS mRNA was determined by quantitative real-time RT-PCR using RNA isolated from renal cells in urine. P15 After 2 hours of mechanical ventilation (FiO2 1,0, respiratory rate 60/min, tidal volume 10 ml/kg, PEEP 2 cmH2O) inspiratory pressures were recorded, rats were sacrificed, the P–V curve of the respiratory system constructed, and bronchoalveolar lavage and aortic blood samples obtained. NO metabolites in blood were not significantly different between AP-treated (n = 10) and placebo-treated (n = 5) patients. However, the urinary excretion of NO metabolites decreased by 80% (75–85) from 227 (166–531) at baseline to 41 (28–84) µmol/ 10 mmol creatinine (P < 0.05) after 24 hours of AP administration. After placebo treatment, the amount of urinary NO metabolites increased by 70% (45–570) (from 81 (64–419) to 628 (65– 1,479) µmol/10 mmol creatinine, P < 0.05). Baseline expression levels of iNOS in renal cells were 42-fold induced at baseline (vs healthy subjects), and AP administration reduced this induction by 80 ± 5% (Figure 1). Creatinine clearance improved by 45% (30–180) in patients treated with AP and declined by 25% (15–35) in placebo-treated patients. During the first 24 hours the amount of GSTA1-1 in urine of AP-treated patients decreased by 70% (50–80), compared with an increase of 200% (45–525) in placebo-treated patients, which correlated with urinary NO metabolites, indicating NO-induced proximal tubular damage. I l i i i i i i AP l i Methods Sixteen male adult Sprague–Dawley rats, instrumented under ether anesthesia with vascular catheters on the previous day, were anesthetized, tracheostomized, connected to a ventilator and randomly allocated to groups of normothermia (37 ± 0.5°C, group N, n = 8) or hypothermia (33 ± 0.5°C, group H, n = 8). After 2 hours of mechanical ventilation (FiO2 1,0, respiratory rate 60/min, tidal volume 10 ml/kg, PEEP 2 cmH2O) inspiratory pressures were recorded, rats were sacrificed, the P–V curve of the respiratory system constructed, and bronchoalveolar lavage and aortic blood samples obtained. Results Group H animals exhibited in comparison with group N animals a lower increase in peak inspiratory pressures (0.7 ± 1.1 vs 2.4 ± 0.5 mmHg, P < 0.001), significant shift of the P–V curve to the left and lower total protein (113 ± 42 vs 201 ± 97 µg/ml, P = 0.047) and TNF (23.5 ± 8.0 vs 35.2 ± 8.5 pg/ml, P = 0,022) levels in BAL samples. Figure 1 (abstract P14) Figure 1 (abstract P14) References References Figure 1 (abstract P14) 1. Lim CM, et al.: Lung 2003, 181:23-34. 2. Suzuki S, et al.: Crit Care Med 2004, 32:144-149. 3. Hong S-B, et al.: Crit Care Med 2005, 33:2049-2055. 4. Muscedere JG, et al.: Am J Respir Crit Care Med 1994, 149: 1327-1334. 5. Fan J, et al.: J Immunol 1998, 161:440-447. 5. Fan J, et al.: J Immunol 1998, 161:440-447. 6. Kaneko A, et al.: J Surg Res 2006, 134:215-222. 6. Kaneko A, et al.: J Surg Res 2006, 134:215-222. Escherichia coli porcine peritonitis induces histological and transcriptome evidence of cardiac injury Escherichia coli porcine peritonitis induces histological and transcriptome evidence of cardiac injury S Heemskerk1, R Masereeuw1, O Moesker2, M Bouw2, J van der Hoeven2,3, W Peters4, M Velders5, F Russel1, P Pickkers2 1Department of Pharmacology and Toxicology, Nijmegen Centre for Medical Life Sciences, 2Department of Intensive Care Medicine, 3Nijmegen University Centre for Infectious Diseases and 4Department of Gastroenterology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; 5AM-Pharma, Bunnik, The Netherlands Critical Care 2007, 11(Suppl 2):P14 (doi: 10.1186/cc5174) R Goldfarb1, I Cinel1, S Gandhi1, L Cinel2, M Levine1, Q Wang3 A Brooks3, J Parrillo1 1Cooper University Hospital and UMDNJ, Camden, NJ, USA; 2Thomas Jefferson University Hospital, Philadelphia, PA, USA; 3EOHSI, UMDNJ, Piscataway, NJ, USA Critical Care 2007, 11(Suppl 2):P13 (doi: 10.1186/cc5173) Introduction Cardiac dysfunction is a feature of sepsis. In order to gain insight into the fundamental mechanisms of this phenotype, Introduction Cardiac dysfunction is a feature of sepsis. In order to gain insight into the fundamental mechanisms of this phenotype, We previously demonstrated that upregulation of renal inducible nitric oxide synthase (iNOS) during systemic inflammation is S5 P15 F Saunders1, M Westphal1, P Enkhbaatar1, J Wang1, M Gonzalez1, Y Nakano1, A Hamahata1, C Jonkam1, R Connelly1, R Cox1, H Hawkins2, F Schmalstieg1, E Horvath3, M Lange1, C Szabo1, L Traber1, D Herndon2, D Traber1 1University of Texas Medical Branch, Galveston, TX, USA; 2Shriners Burns Hospital for Children, Galveston, TX, USA; 3University of Medicine and Dentistry of New Jersey, NJ, USA Critical Care 2007, 11(Suppl 2):P16 (doi: 10.1186/cc5176) P15 The urinary excretion of the cytosolic glutathione S-transferase-A1 (GSTA1-1), a marker for proximal tubule damage, was measured using an ELISA. Data are depicted as the median (25–75% range). Introduction Hypothermia was shown to attenuate ventilator- induced lung injury (VILI) in high end-inspiratory lung volume models of VILI [1-3]. Experimental evidence suggests that moderate tidal volumes may, under certain clinical conditions that induce alveolar instability, lead to a lung injury [4]. Recent studies have also suggested that insults like shock [5] or surgery [6] sensitize the lung to injury by priming for an exaggerated response to a second stimulus. The aim of this study was to investigate whether moderate hypothermia attenuates low lung volume injury during low PEEP, high FiO2 and moderate tidal volume ventilation in animals sensitized to injury by previous anesthesia and surgery. Methods Sixteen male adult Sprague–Dawley rats, instrumented under ether anesthesia with vascular catheters on the previous day, were anesthetized, tracheostomized, connected to a ventilator and randomly allocated to groups of normothermia (37 ± 0.5°C, group N, n = 8) or hypothermia (33 ± 0.5°C, group H, n = 8). After 2 hours of mechanical ventilation (FiO2 1,0, respiratory rate 60/min, tidal volume 10 ml/kg, PEEP 2 cmH2O) inspiratory pressures were recorded, rats were sacrificed, the P–V curve of the respiratory system constructed, and bronchoalveolar lavage and aortic blood samples obtained. Introduction Hypothermia was shown to attenuate ventilator- induced lung injury (VILI) in high end-inspiratory lung volume models of VILI [1-3]. Experimental evidence suggests that moderate tidal volumes may, under certain clinical conditions that induce alveolar instability, lead to a lung injury [4]. Recent studies have also suggested that insults like shock [5] or surgery [6] sensitize the lung to injury by priming for an exaggerated response to a second stimulus. The aim of this study was to investigate whether moderate hypothermia attenuates low lung volume injury during low PEEP, high FiO2 and moderate tidal volume ventilation in animals sensitized to injury by previous anesthesia and surgery. Methods Sixteen male adult Sprague–Dawley rats, instrumented under ether anesthesia with vascular catheters on the previous day, were anesthetized, tracheostomized, connected to a ventilator and randomly allocated to groups of normothermia (37 ± 0.5°C, group N, n = 8) or hypothermia (33 ± 0.5°C, group H, n = 8). P15 In conclusion, in septic patients, infusion of AP results in an attenuated upregulation of iNOS and, subsequent, reduced NO production in the kidney, associated with an improvement in renal function. Conclusion Moderate hypothermia attenuated lung injury during low PEEP, high FiO2 and moderate tidal volume ventilation in animals sensitized to injury by previous anesthesia and surgery. Acknowledgement Supported by the Research project MZO 00179906. Acknowledgement Supported by the Research project MZO 00179906. P17 Results (1) The mean arterial pressure was higher post- resuscitation (PR) in group III (62.9 ± 8.2 mmHg) than in groups I and II (54.9 ± 1.7, 53.9 ± 4.3 mmHg; P < 0.01). The urine output (I: 999 ± 428, II: 1,249 ± 180, III: 1,434 ± 325 ml) and the cardiac output (CO) (I: 3.01 ± 0.66, II: 3.30 ± 0.49, III: 3.43 ± 0.57 l/min) increased dose dependently. The volume of third space fluid loss of group III decreased significantly (I: 157 ± 32, II: 138 ± 32, III: 82 ± 21 ml; P < 0.05). (2) Mean arterial pressure was higher PR among groups IV, V and VII (71.4 ± 7.5, 71.0 ± 8.9, 72.9 ± 12.3 mmHg) compared with group VI (59.9 ± 10.9) and CO of PR was higher in group VII (3.46 ± 0.56 l/min) than group IV (2.99 ± 0.62; P < 0.01). Following resuscitation, the urine output was higher, and the urine specific gravity and third space fluid loss were lower in group VII (1,434 ± 325 ml, 1.0035, 82 ± 21 ml) compared with group VI (958 ± 390 ml, 1.0053, 125 ± 32 ml; P < 0.05). nNOS and Nox4 go nuclear: nNOS-derived and NADPH oxidase-derived reactive oxygen/nitrogen species promote oxidative nuclear damage in alveolar epithelial cells nNOS and Nox4 go nuclear: nNOS-derived and NADPH oxidase-derived reactive oxygen/nitrogen species promote oxidative nuclear damage in alveolar epithelial cells R Connelly, F Schmalstieg, D Traber University of Texas Medical Branch, Galveston, TX, USA Critical Care 2007, 11(Suppl 2):P17 (doi: 10.1186/cc5177) Emerging evidence implicates a role for angiotensin II (Ang II)- stimulated reactive oxygen and nitrogen species (ROS/RNS) formation in acute lung injury (ALI). However, details of the mechanism are lacking. We hypothesized that compartmentalized generation of superoxide (O2–) and nitric oxide (•NO) may be key events in the Ang II-stimulated progression of ALI. In the present study, we found that Ang II markedly enhanced ROS/RNS production 7.4-fold, an effect blocked by the specific nNOS inhibitor N(G)-propyl-L-arginine, the NADPH oxidase inhibitor apocynin, or small interfering RNA (siRNA)-specific gene silencing targeted against nNOS or Nox4. nNOS/Nox4 transiently co- immunoprecipitates, and co-localizes at the peri-nuclear region 15 minutes post Ang II stimulation. Subsequently, confocal and western blot analyses show that nNOS/Nox4 translocates to the nucleus, suggesting that nNOS/Nox4 may directly regulate nuclear signaling. Dose effects of recombinant human IL-11 on the systemic hemodynamic function in hemorrhagic shock Methods Eleven ewes were surgically instrumented and randomly allocated to either an injured untreated control group (40% total body surface area flame burn and 48 breaths of cotton smoke, n = 6), or an injury group treated with 7-NI (1 mg/kg/hour, n = 5). K Honma1, N Koles2, H Alam2, P Rhee2, J Keith, Jr3, M Pollack2 1Shin-Koga Hospital, Kurume, Fukuoka, Japan; 2Uniformed Services University of the Health Sciences, Bethesda, MD, USA; 3Wyeth Research, Andover, MA, USA Critical Care 2007, 11(Suppl 2):P18 (doi: 10.1186/cc5178) Results This insult was associated with systemic inflammation and oxidative stress, as evidenced by a 2.5-fold increase in plasma nitrite/nitrate (NOx) levels, as well as sixfold, twofold, threefold and twofold increases in IL-8, myeloperoxidase (MPO), malondialde- hyde (MDA) and poly-ADP-ribose-polymerase (PARP) lung tissue concentrations, respectively. These molecular changes were linked to severe pulmonary derangements. Compared with untreated controls, 7-NI significantly reduced NOx plasma levels (8.4 ± 1 vs 26 ± 10 µmol/l) and decreased IL-8, MPO (3.9 ± 0.2 vs 5.8 ± 0.7 U/g tissue), MDA (2.7 ± 0.3 vs 6.6 ± 1.1 nmol/mg protein) and PARP lung tissue content (3.4 ± 0.7 vs 6.7 ± 0.7), thereby decreasing pulmonary obstruction (12.4 ± 2.2 vs 28.7 ± 5.2 obstruction score) and increasing the PaO2/FiO2 ratio (456 ± 40 vs 313 ± 56, each P < 0.05). Introduction We have previously demonstrated that administration of recombinant human IL-11 (rhIL-11) during resuscitation improves the cardiovascular functions in a rodent model of hemorrhagic shock. The purpose of this study was to elucidate: (1) whether these beneficial effects were dose related, and (2) whether the effects of rhIL-11 could be reproduced in a large animal model. p g Methods Swine (n = 56, weight = 25–35 kg) underwent 40% blood volume hemorrhage, and a 1-hour shock period, followed by resuscitation with 0.9% sodium chloride (three times the shed blood volume). The animals were randomized to receive: (1) group I, 5 µg/kg rhIL-11 (n = 6); group II, 20 µg/kg rhIL-11 (n = 5); group III, 50 µg/kg rhIL-11 (n = 6) – and then, (2) group IV, sham hemorrhage (sham, n = 10); group V, sham hemorrhage and 50 µg/kg rhIL-11 (sham + IL-11, n = 6); group VI, no drug (saline, n = 15); group VII, 50 µg/kg rhIL-11 (IL-11, n = 14). Dose effects of recombinant human IL-11 on the systemic hemodynamic function in hemorrhagic shock Blood samples and urine were obtained and analyzed at baseline, the end of hemorrhage, and at every hour. Conclusions These data suggest that nNOS-derived NO plays a pivotal role in the pathophysiology of this double-hit injury and that selective nNOS inhibition may represent a useful approach to attenuate the degree of pulmonary damage. Effects of neuronal nitric oxide synthase in ovine lung injury P17 nNOS and Nox4 go nuclear: nNOS-derived and NADPH oxidase-derived reactive oxygen/nitrogen species promote oxidative nuclear damage in alveolar epithelial cells R Connelly, F Schmalstieg, D Traber University of Texas Medical Branch, Galveston, TX, USA Critical Care 2007, 11(Suppl 2):P17 (doi: 10.1186/cc5177) P18 P17 Furthermore, PAR polymers, which are undetectable in resting conditions, were generated following Ang II stimulation, an effect blocked with apocynin or N(G)-propyl-L-arginine. In conclusion, these data suggest Ang II causes nNOS/Nox4 to co- localize at the peri-nuclear region of A549 cells, where superoxide produced by Nox4, and •NO produced by nNOS immediately react to form peroxynitrite, which leads to subsequent nuclear oxidative damage as evidenced by increased PAR polymer formation. Furthermore, these experiments demonstrate inflammatory-stimulated nuclear translocalization of nNOS/Nox4, which has important implications for direct ROS/RNS-mediated nuclear activities. Therefore, inhibition of nNOS/Nox4 may be an effective thera- peutic target in patients with ALI. Conclusion The effects of rhIL-11 on the cardiovascular functions were influenced by the dose of rhIL-11, although the relationship did not follow simple linearity. A 50µg/kg dose rhIL-11 significantly improves cardiovascular functions in a porcine model of hemor- rhagic shock. Effects of neuronal nitric oxide synthase in ovine lung injury F Saunders1, M Westphal1, P Enkhbaatar1, J Wang1, M Gonzalez1, Y Nakano1, A Hamahata1, C Jonkam1, R Connelly1, R Cox1, H Hawkins2, F Schmalstieg1, E Horvath3, M Lange1, C Szabo1, L Traber1, D Herndon2, D Traber1 1University of Texas Medical Branch, Galveston, TX, USA; 2Shriners Burns Hospital for Children, Galveston, TX, USA; 3University of Medicine and Dentistry of New Jersey, NJ, USA Critical Care 2007, 11(Suppl 2):P16 (doi: 10.1186/cc5176) F Saunders1, M Westphal1, P Enkhbaatar1, J Wang1, M Gonzalez1, Y Nakano1, A Hamahata1, C Jonkam1, R Connelly1, R Cox1, H Hawkins2, F Schmalstieg1, E Horvath3, M Lange1, C Szabo1, L Traber1, D Herndon2, D Traber1 1University of Texas Medical Branch, Galveston, TX, USA; 2Shriners Burns Hospital for Children, Galveston, TX, USA; 3University of Medicine and Dentistry of New Jersey, NJ, USA Critical Care 2007, 11(Suppl 2):P16 (doi: 10.1186/cc5176) Introduction Excessive production of nitric oxide is a major factor contributing to acute lung injury and systemic inflammation after S6 Available online http://ccforum.com/supplements/11/S2 burn and smoke inhalation injury. We hypothesized that the use of 7-nitroindazole (7-NI), a selective nNOS inhibitor, blocks molecular mechanisms in this pathogenesis. Methods Eleven ewes were surgically instrumented and randomly allocated to either an injured untreated control group (40% total body surface area flame burn and 48 breaths of cotton smoke, n = 6), or an injury group treated with 7-NI (1 mg/kg/hour, n = 5). Results This insult was associated with systemic inflammation and oxidative stress, as evidenced by a 2.5-fold increase in plasma nitrite/nitrate (NOx) levels, as well as sixfold, twofold, threefold and twofold increases in IL-8, myeloperoxidase (MPO), malondialde- hyde (MDA) and poly-ADP-ribose-polymerase (PARP) lung tissue concentrations, respectively. These molecular changes were linked to severe pulmonary derangements. Compared with untreated controls, 7-NI significantly reduced NOx plasma levels (8.4 ± 1 vs 26 ± 10 µmol/l) and decreased IL-8, MPO (3.9 ± 0.2 vs 5.8 ± 0.7 U/g tissue), MDA (2.7 ± 0.3 vs 6.6 ± 1.1 nmol/mg protein) and PARP lung tissue content (3.4 ± 0.7 vs 6.7 ± 0.7), thereby decreasing pulmonary obstruction (12.4 ± 2.2 vs 28.7 ± 5.2 obstruction score) and increasing the PaO2/FiO2 ratio (456 ± 40 vs 313 ± 56, each P < 0.05). Conclusions These data suggest that nNOS-derived NO plays a pivotal role in the pathophysiology of this double-hit injury and that selective nNOS inhibition may represent a useful approach to attenuate the degree of pulmonary damage. P18 burn and smoke inhalation injury. We hypothesized that the use of 7-nitroindazole (7-NI), a selective nNOS inhibitor, blocks molecular mechanisms in this pathogenesis. P18 Dose effects of recombinant human IL-11 on the systemic hemodynamic function in hemorrhagic shock K Honma1, N Koles2, H Alam2, P Rhee2, J Keith, Jr3, M Pollack2 1Shin-Koga Hospital, Kurume, Fukuoka, Japan; 2Uniformed Services University of the Health Sciences, Bethesda, MD, USA; 3Wyeth Research, Andover, MA, USA Critical Care 2007, 11(Suppl 2):P18 (doi: 10.1186/cc5178) Degradation of endothelial glycocalyx provides new insights in the pathogenesis of septic shock microvascular failure GLX degradation plays a critical ro in the septic vasculature and generation of free radicals durin septic shock is potentially toxic to GLX function. P20 Exhaled breath condensate mediators in mechanically ventilated brain-injured patients with no acute lung injury are mostly related to markers of systemic inflammation I Korovesi1, E Papadomichelakis2, O Livaditi1, E Giamarellos- Bourboulis3, C Sotiropoulou1, A Koutsoukou4, I Dimopoulou2, A Armaganidis2, C Roussos4, N Marczin5, A Kotanidou4, S Orfanos2 1University of Athens, Greece; 2Attikon Hospital, 2nd Critical Care Department, Haidari (Athens), Greece; 3Attikon Hospital, 4th Department of Medicine, Haidari (Athens), Greece; 4Evangelismos Hospital, Athens, Greece; 5Imperial College London, UK Critical Care 2007, 11(Suppl 2):P20 (doi: 10.1186/cc5180) Introduction Mechanical ventilation may induce lung injury pathologies. In this study we identified EBC inflammatory markers in 27 mechanically ventilated brain-injured subjects with neither acute lung injury (ALI) nor sepsis. apparent thickness evaluated using intravital microscopy by comparing 4 and 150 kDa dextran distribution as markers of GLX permeable and impermeable tracers, respectively. Intravital micro- scopy was used to characterize mesentery functional capillary density. Because glycocalyx is extremely sensitive to free radical, oxidative stress was evaluated by oxidation of dihydrorhodamine (DHR) in microvascular beds and by concentrations of heart malondialdehyde (MDA) and plasma carbonyl proteins (CP). g j y p Methods Patients were ventilated with 8 ml/kg tidal volume and were put either on PEEP = 0 (ZEEP, n = 12) or 8 cmH2O (PEEP, n = 15). EBC was collected using the RTube device (Respiratory Research Inc., Charlottesville, VA, US) on the first, third, and fifth day of mechanical ventilation, and pH, IL-10, IL-1β, IL-6, IL-8, IL-12p70 and TNFα were measured. Applying mixed effects models, we further investigated potential relationships of the above EBC markers with indices of: i, lung injury (LIS score, PaO2/FiO2, detected pathologies on lung CT); ii, brain injury (ICP, CPP, GCS, serum (s) S100 protein, pentothal and mannitol administration); iii, endothelial injury (sICAM-1, sVCAM-1, von Willebrand factor antigen); iv, systemic inflammation (temperature, leukocyte counts and neutrophil counts in blood, albumin, soluble triggering receptor expressed on myeloid cells (sTREM), CRP, procalcitonin (PCT) and all above-mentioned cytokines in serum or plasma); and v, disease severity (APACHE II score, 24 hour ICU trauma score, presence of SIRS, mean arterial pressure). Results LPS elicited a 4 hours later profound reduction in GLX layer thickness and increase in plasma hyaluronan levels. Degradation of endothelial glycocalyx provides new insights in the pathogenesis of septic shock microvascular failure LPS rats had decreases in capillary continuous flow, and significant increases in intermittent and stopped flow capillaries compared with controls. The pressor responses to norepinephrine were greatly reduced, indicative of vascular hyporeactivity. In vivo oxidation of DHR and levels of heart MDA and plasma CP were all increased in LPS- treated rats. Interestingly, in LPS rats, APC reduced plasma hyaluronan levels and GLX destruction, which was accompanied with major improvements in vasopressor response and functional capillary density. APC treatment also prevented increases in biochemical and in vivo microvascular oxidative stress markers. The pressor responses to norepinephrine were greatly reduced, indicative of vascular hyporeactivity. In vivo oxidation of DHR and levels of heart MDA and plasma CP were all increased in LPS- treated rats. Interestingly, in LPS rats, APC reduced plasma hyaluronan levels and GLX destruction, which was accompanied with major improvements in vasopressor response and functional capillary density. APC treatment also prevented increases in biochemical and in vivo microvascular oxidative stress markers. Results No significant differences in EBC measurements were observed between the two groups except a time-dependent decrease in IL-10 (P < 0.05, by ANOVA) in the PEEP group. EBC pH and IL-10 showed no significant relationships (mixed effects models) with any parameter measured. All other EBC cytokines were inversely related to sTREM levels. Additional significant relationships were obtained between individual EBC cytokines and sIL-8 (IL-8, IL-12p70, TNFα), sIL-6 (IL-1β), PCT (IL-1β, IL-12p70), the existence of SIRS (IL- 6, IL-8), sVCAM-1 (IL-6), and pentothal administration (IL-1β). Conclusion In our model of septic shock, increased plasma hyluronan levels and reduction in endothelial layer thickness indicated GLX degradation. APC prevented vascular oxidative stress and limited GLX loss. GLX degradation plays a critical role in the septic vasculature and generation of free radicals during septic shock is potentially toxic to GLX function. Reduced local inflammatory reactivity in septic patients compared with healthy controls Introduction Mechanical ventilation may induce lung injury in patients with normal lungs. Application of PEEP appears protective. Lung injury is associated with the production and release of inflammatory mediators. Such mediators have been identified in patients’ exhaled breath condensate (EBC) in various lung Introduction The aim of this study was to access the local inflammatory reactivity by measurement of the cytokine response Exhaled breath condensate mediators in mechanically ventilated brain-injured patients with no acute lung injury are mostly related to markers of systemic inflammation Conclusion In our population of mechanically ventilated, brain- injured patients with no ALI, ZEEP or applied PEEP did not induce detectable changes in most lung inflammatory mediators in EBC; the latter appear mostly related to markers of systemic inflammation (especially sTREM-1) rather than to indices of brain and endothelial injury. I Korovesi1, E Papadomichelakis2, O Livaditi1, E Giamarellos- Bourboulis3, C Sotiropoulou1, A Koutsoukou4, I Dimopoulou2, A Armaganidis2, C Roussos4, N Marczin5, A Kotanidou4, S Orfanos2 1University of Athens, Greece; 2Attikon Hospital, 2nd Critical Care Department, Haidari (Athens), Greece; 3Attikon Hospital, 4th Department of Medicine, Haidari (Athens), Greece; 4Evangelismos Hospital, Athens, Greece; 5Imperial College London, UK Critical Care 2007, 11(Suppl 2):P20 (doi: 10.1186/cc5180) I Korovesi1, E Papadomichelakis2, O Livaditi1, E Giamarellos- Bourboulis3, C Sotiropoulou1, A Koutsoukou4, I Dimopoulou2, A Armaganidis2, C Roussos4, N Marczin5, A Kotanidou4, S Orfanos2 P20 Exhaled breath condensate mediators in mechanically ventilated brain-injured patients with no acute lung injury are mostly related to markers of systemic inflammation P21 1University of Athens, Greece; 2Attikon Hospital, 2nd Critical Care Department, Haidari (Athens), Greece; 3Attikon Hospital, 4th Department of Medicine, Haidari (Athens), Greece; 4Evangelismos Hospital, Athens, Greece; 5Imperial College London, UK Critical Care 2007, 11(Suppl 2):P20 (doi: 10.1186/cc5180) Degradation of endothelial glycocalyx provides new insights in the pathogenesis of septic shock microvascular failure Degradation of endothelial glycocalyx provides new insights in the pathogenesis of septic shock microvascular failure R Nevière1, R Favory2, X Marechal1 1School of Medicine, Lille, France; 2Calmette Hospital, Lille, France Critical Care 2007, 11(Suppl 2):P19 (doi: 10.1186/cc5179) R Nevière1, R Favory2, X Marechal1 1School of Medicine, Lille, France; 2Calmette Hospital, Lille, France Critical Care 2007, 11(Suppl 2):P19 (doi: 10.1186/cc5179) Introduction Glycocalyx (GLX) is implicated in mechanotrans- duction of shear stress and microvascular blood flow. We tested whether GLX loss accounts for the microvascular dysfunction in sepsis and whether activated protein C (APC) preserves endothelial GLX integrity. Introduction Glycocalyx (GLX) is implicated in mechanotrans- duction of shear stress and microvascular blood flow. We tested whether GLX loss accounts for the microvascular dysfunction in sepsis and whether activated protein C (APC) preserves endothelial GLX integrity. Methods Endotoxin LPS (10 mg/kg) was infused in rats treated or not with APC (240 µg/kg/hour). Changes in GLX were assessed by circulating levels of hyaluronan (a GLX constituent) and by GLX S7 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin apparent thickness evaluated using intravital microscopy b comparing 4 and 150 kDa dextran distribution as markers of GL permeable and impermeable tracers, respectively. Intravital micro scopy was used to characterize mesentery functional capilla density. Because glycocalyx is extremely sensitive to free radica oxidative stress was evaluated by oxidation of dihydrorhodamin (DHR) in microvascular beds and by concentrations of hea malondialdehyde (MDA) and plasma carbonyl proteins (CP). Results LPS elicited a 4 hours later profound reduction in GL layer thickness and increase in plasma hyaluronan levels. LPS rat had decreases in capillary continuous flow, and significant increase in intermittent and stopped flow capillaries compared with control The pressor responses to norepinephrine were greatly reduced indicative of vascular hyporeactivity. In vivo oxidation of DHR an levels of heart MDA and plasma CP were all increased in LPS treated rats. Interestingly, in LPS rats, APC reduced plasm hyaluronan levels and GLX destruction, which was accompanie with major improvements in vasopressor response and function capillary density. APC treatment also prevented increases biochemical and in vivo microvascular oxidative stress markers. Conclusion In our model of septic shock, increased plasm hyluronan levels and reduction in endothelial layer thicknes indicated GLX degradation. APC prevented vascular oxidativ stress and limited GLX loss. P22 The evaluation of sivelestat sodium hydrate in acute lung injury/acute respiratory distress syndrome patients in the intensive care unit T Ikeda, K Ikeda, T Ueno, Y Kuroki, T Yokoyama, K Yoshikawa Hachiouji Medical Center, Tokyo Medical University, Tokyo, Japan Critical Care 2007, 11(Suppl 2):P22 (doi: 10.1186/cc5182) The evaluation of sivelestat sodium hydrate in acute lung injury/acute respiratory distress syndrome patients in the intensive care unit Methods Male BALB/c mice were divided into three groups. Group I served for sham burns. In groups II and III, a 15% BSA full- thickness burn was made on the dorsum under ether anesthesia, followed by adequate fluid resuscitation. After the burn injury, 3 mg/kg prednisolone (PSL) in group III was administered sub- cutaneously daily for 10 days. On the 11th day, 10 mg/kg lipopolysaccharide (LPS) was injected intravenously. In the first experiment, we observed the survival within 72 hours after LPS injection in each group (n = 10). In the second experiment, we sacrificed the animals at 12 hours after LPS injection, then obtained plasma and lung tissue to determine the levels of TNFα and macrophage inflammatory protein-2 (MIP-2, a functional homo- logue of human IL-8 in mice) in these samples (n = 8, sandwich ELISA). We also determined gene expression (n = 4, MIP- 2/GAPDH mRNA ratio by RT-PCR), myeloperoxidase activities (MPO, n = 8) and histopathological findings in the lung tissue. T Ikeda, K Ikeda, T Ueno, Y Kuroki, T Yokoyama, K Yoshikawa Hachiouji Medical Center, Tokyo Medical University, Tokyo, Japan Critical Care 2007, 11(Suppl 2):P22 (doi: 10.1186/cc5182) The onset mechanism of ALI/ARDS and subsequent tissue injury are considered to be associated with neutrophil elastase, and the main causes of ALI/ARDS are considered to be sepsis or aspiration pneumonia. In Japan, sivelestat sodium hydrate (Elaspol), a selective elastase inhibitor, was approved in 2002 for ALI/ARDS accompanied by SIRS, and this medicine has been evaluated in a clinical situation. Figure 1 (abstract P21) Figure 1 (abstract P21) Figure 1 (abstract P21) S8 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Elaspol: 75%, Group Control: 52%; P < 0.001). These results suggest that sivelestat sodium hydrate is a good option as a treatment strategy for neutrophil elastase-associated septic ALI/ARDS accompanied by SIRS. after catheter insertion into subcutaneous adipose tissue (SAT) of patients with severe sepsis compared with healthy volunteers. Elaspol: 75%, Group Control: 52%; P < 0.001). These results suggest that sivelestat sodium hydrate is a good option as a treatment strategy for neutrophil elastase-associated septic ALI/ARDS accompanied by SIRS. after catheter insertion into subcutaneous adipose tissue (SAT) of patients with severe sepsis compared with healthy volunteers. Methods Eight healthy volunteers and 10 patients with severe sepsis were included. One 18-gauge open-flow microperfusion double-lumen catheter was inserted into SAT of the abdominal wall and perfused with an isotonic solution at a flow rate of 1 µl/min. Blood samples and probe effluent samples from interstitial fluid of SAT were withdrawn in two hourly intervals for a period of 8 hours and retrospectively analysed using a Multiplex ELISA system for IL-1β, IL-6, IL-8 and TNFα. Methods Eight healthy volunteers and 10 patients with severe sepsis were included. One 18-gauge open-flow microperfusion double-lumen catheter was inserted into SAT of the abdominal wall and perfused with an isotonic solution at a flow rate of 1 µl/min. Blood samples and probe effluent samples from interstitial fluid of SAT were withdrawn in two hourly intervals for a period of 8 hours and retrospectively analysed using a Multiplex ELISA system for IL-1β, IL-6, IL-8 and TNFα. P22 In this study, we performed a retrospective comparison of the sivelestat sodium administration between two groups of patients: Group Elaspol, consisting of 308 patients(209 males and 99 females, aged 66 ± 15 years) with ALI/ARDS accompanied by SIRS who were treated with sivelestat sodium at a dose of 0.2 mg/kg/hour for 72 hours or more, after approval of this drug; and Group Control, consisting of 41 patients (28 males and 13 females, aged 66 ± 14 years) with ALI/ARDS accompanied by SIRS who were treated in the ICU under similar conditions, but using traditional methods for respiratory control, prior to approval sivelestat sodium. The APACHE II scores of Group Elaspol and Group Control were 23 ± 9 and 23 ± 8, SOFA scores were 8.7 ± 3.8 and 8.9 ± 4.1, and the lung injury scores were 2.1 ± 0.7 and 2.1 ± 0.6, respectively, with no significant differences between the groups. The initial PEEP value of Group Elaspol was 5.9 ± 3.3, which was significantly higher than that of Group Control (3.4 ± 2.7 cmH2O). The PaO2/FIO2 ratios under mechanical ventilation management 24, 48 and 72 hours after the beginning of drug administration were 209 ± 87, 222 ± 92, and 222 ± 82 mmHg in Group Elaspol, and were 191 ± 91, 207 ± 91, and 211 ± 100 mmHg in Group Control. The ventilator-free days of Group Elaspol and Group Control were 18 ± 9 and 10 ± 12 days, respectively, and these values showed a significant difference (P < 0.001). Furthermore, the survival rate after 28 days was significantly higher in Group Elaspol than in Group Control (Group Results The survival and production of cytokines are shown in Table 1. Histopathological findings in group III were obviously attenuated. Table 1 (abstract P23) Lung MIP-2/ Plasma Plasma Lung GAPDH Lung Survival TNF MIP-2 MIP-2 mRNA MPO Group (%) (pg/ml) (pg/ml) (pg/mg) ratio (U/mg) I (sham–LPS) 100 1,190 6,396 70.0 0.345 0.405 II (burn–LPS) 0† 3,024** 13,766** 142.5** 0.975‡ 0.574** III (PSL) 50* 749§ 791§ 11.6§ 0.052§ 0.244§ Mean values are presented. *P < 0.05 vs group II, **P < 0.005 vs group I, †P < 0.01 vs group I, ‡P < 0.05 vs group I, §P < 0.005 vs group II. Conclusions In this animal model, a pretreatment with PSL as the cytokine synthesis inhibitor improved the survival and attenuated the production of cytokines. P23 Pharmacological modulation with prolonged administration of moderate doses of steroid in a murine model of septic acute lung injury after burn insult J Sasaki1, S Fujishima2, K Takuma1, Y Shinozawa1, N Aikawa2 1Tohoku University Hospital, Sendai, Japan; 2Keio University, Tokyo, Japan Critical Care 2007, 11(Suppl 2):P23 (doi: 10.1186/cc5183) Results Concentrations of IL-1β, IL-6 and IL-8 were substantially higher in SAT (13.3 (11.2; 31.0); 1,934 (1,650; 2,730); 917 (656; 2,672) pg/ml; median (25th; 75th percentile)) than in serum (0.8 (0.6; 1.3); 49.2 (3.8; 67.6); 36.1 (6.3; 89.1) pg/ml) for both groups, whereas TNFα concentrations were similar in serum and SAT (Figure 1). Serum concentrations of all cytokines remained stable over time. However, a significant increase was observed for IL-1β and IL-8 in SAT in both groups. This increase was significantly in septic patients vs healthy controls. ritical Care 2007, 11(Suppl 2):P23 (doi: 10.1186/cc518 Introduction Many patients who experience surgical stress including burn injury become susceptible to severe sepsis and septic organ dysfunction including acute lung injury (ALI), which remains the primary contributor to morbidity and mortality in burn patients. Proinflammatory cytokines including several chemokines are implicated in this process. The pharmacological modulation with steroid inhibiting the process of cytokine synthesis may serve as effective therapy for the prevention of tissue injury and the resultant organ dysfunction including respiratory failure. We developed a murine model of septic ALI after burn insult and examined the effects of prolonged administration of moderate doses of steroid. Introduction Many patients who experience surgical stress including burn injury become susceptible to severe sepsis and septic organ dysfunction including acute lung injury (ALI), which remains the primary contributor to morbidity and mortality in burn patients. Proinflammatory cytokines including several chemokines are implicated in this process. The pharmacological modulation with steroid inhibiting the process of cytokine synthesis may serve as effective therapy for the prevention of tissue injury and the resultant organ dysfunction including respiratory failure. We developed a murine model of septic ALI after burn insult and examined the effects of prolonged administration of moderate doses of steroid. Conclusion Insertion of a catheter into subcutaneous adipose tissue promotes a local inflammatory response in both healthy individuals and critically ill patients. The attenuated response in patients with severe sepsis might be caused by reduced inflammatory reactivity in this group. Glucosamine enhances heat shock protein 70 expression in vitro and in vivo following injury Glucosamine enhances heat shock protein 70 expression in vitro and in vivo following injury K Singleton, C Hamiel, P Wischmeyer University of Colorado Health Sciences Center, Denver, CO, USA Critical Care 2007, 11(Suppl 2):P24 (doi: 10.1186/cc5184) Methods To investigate the therapeutic effect of nicotine and physostigmine we performed cecal ligation and puncture (CLP) in female C57/B6 mice (each group n = 21). Substances were administered by intraperitoneal injection. Control groups received the same volume (50–180 µl) of LPS-free 0.9% NaCl (solvent). CLP was performed blinded to the identity of the treatment group. In addition to survival experiments we performed measurements of cytokines in plasma and the electrophoretic mobility shift assay (EMSA) for NF-κB in peritoneal skin, liver and kidneys. Introduction Enhanced activity of the O-glycosylation pathway (O- glcNAc) has been shown to enhance increase heat shock protein (HSP70) expression. Glucosamine (GA) is a vital intermediate in this pathway. Methods Mouse fibroblast (MEF) cells underwent heat stress (HS) at 43°C for 45 minutes. GA doses from 1.25 to 20 mM were given immediately prior to HS. Cell survival was assessed via MTS assay. GA’s effect on HSP70 expression in vivo was assessed using a mouse model of cecal ligation and puncture (CLP). Mice were given 0.26 g/kg GA i.v. 1 hour post CLP. Results (1) Animals treated with nicotine (400 µg/kg) or physostigmine (80 µg/kg) survived significantly better than control mice (P < 0.05). There was no difference between the treatment groups. (2) Dose escalation of physostigmine was not superior to the normal dose. Survival in the high-dose group, however, was still significantly better than in the control group. (3) Proinflammatory cytokine levels of TNFα, IL-6 and IL-1β were significantly reduced in animals treated with physostigmine (P < 0.01). (4) Cholin- esterase inhibition with physostigmine in CLP reduced NF-κB activation in the peritoneum, kidney and liver compared with the control and sham-operated group (P < 0.01). Results In MEF cells, 10 mM GA led to a 164% increase in HSP70 expression over control 4 hours post HS (P < 0.05 vs control). Further, GA treatment led to an increase in cell survival post HS injury at all doses tested (P < 0.01 vs control). Following CLP- induced sepsis, a single dose of GA led to an increase in lung and heart HSP70 at 1 and 2 hours post CLP vs saline control (SC). Glucosamine enhances heat shock protein 70 expression in vitro and in vivo following injury This effect was lost at 6 and 24 hours (see Figure 1, *P < 0.05 versus SC at each timepoint). Similarly, GA led to an increase in HSP70 in colon tissue as well, with the effect lasting to 6 hours (*P < 0.05 versus SC). The effect in colon was lost by 24 hours. Conclusion We show that pharmacological cholinesterase inhibition with physostigmine improves survival in experimental sepsis, most probably by activation of the cholinergic anti-inflam- matory pathway. One possible mechanism is modulation of the NF- κB pathway. Therefore, cholinesterase inhibition may have important implications for treatment of sepsis. Conclusions To our knowledge, this is the first report that shows GA treatment can increase HSP70 expression both in vivo and in vitro. Previous data have demonstrated beneficial effects of GA treatment following ischemia/reperfusion injury and hemorrhagic shock early after injury. GA’s effect on HSP70 expression in multiple tissues may help to explain these effects. Further, GA’s effect on HSP70 expression may be an important factor involved in GA’s benefits in arthritis and joint disease. P24 P24 inflammatory mechanisms. Vagus nerve stimulation showed improved survival in sepsis; however, this seems not to be feasible in septic patients. We therefore investigated the effect of activation of the cholinergic anti-inflammatory pathway by pharmacologic cholin- esterase inhibition on survival and inflammation in a septic mouse model. P24 Glucosamine enhances heat shock protein 70 expression in vitro and in vivo following injury K Singleton, C Hamiel, P Wischmeyer University of Colorado Health Sciences Center, Denver, CO, USA Critical Care 2007, 11(Suppl 2):P24 (doi: 10.1186/cc5184) Glucosamine enhances heat shock protein 70 expression in vitro and in vivo following injury P22 The complications associated with sepsis after burn insults, especially ALI, could be preventable by the pharmacological modulation with prolonged administration of moderate doses of steroid. S9 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin 0 P24 Glucosamine enhances heat sho in vitro and in vivo following injur K Singleton, C Hamiel, P Wischmey University of Colorado Health Scienc Critical Care 2007, 11(Suppl 2):P24 Introduction Enhanced activity of the glcNAc) has been shown to enhanc (HSP70) expression. Glucosamine ( this pathway. Methods Mouse fibroblast (MEF) cel at 43°C for 45 minutes. GA doses fro immediately prior to HS. Cell survival GA’s effect on HSP70 expression i mouse model of cecal ligation and given 0.26 g/kg GA i.v. 1 hour post C Results In MEF cells, 10 mM GA led expression over control 4 hours po Further, GA treatment led to an inc injury at all doses tested (P < 0.01 induced sepsis, a single dose of GA heart HSP70 at 1 and 2 hours post C effect was lost at 6 and 24 hours (s SC at each timepoint). Similarly, GA l colon tissue as well, with the effect versus SC). The effect in colon was lo Conclusions To our knowledge, this GA treatment can increase HSP70 e vitro. Previous data have demonstra treatment following ischemia/reperfu shock early after injury. GA’s effe multiple tissues may help to explain effect on HSP70 expression may be GA’s benefits in arthritis and joint dis P25 Pharmacologic inhibition of choli survival in experimental sepsis S Hofer, C Eisenbach, I Lukic, L Sc M Büchler, A Bierhaus, M Weigand University of Heidelberg, Germany Critical Care 2007, 11(Suppl 2):P25 Introduction Lethal sepsis occurs response evolves that cannot be co Figure 1 (abstract 24) Lung heat shock protein (HSP70) expre following cecal ligation and puncture. P24 Glucosamine enhances heat shock protein 70 expression in vitro and in vivo following injury K Singleton, C Hamiel, P Wischmeyer University of Colorado Health Sciences Center, Denver, CO, USA Critical Care 2007, 11(Suppl 2):P24 (doi: 10.1186/cc5184) Introduction Enhanced activity of the O-glycosylation pathway (O glcNAc) has been shown to enhance increase heat shock protei (HSP70) expression. Glucosamine (GA) is a vital intermediate i this pathway. Methods Mouse fibroblast (MEF) cells underwent heat stress (HS at 43°C for 45 minutes. GA doses from 1.25 to 20 mM were give immediately prior to HS. P22 Cell survival was assessed via MTS assay GA’s effect on HSP70 expression in vivo was assessed using mouse model of cecal ligation and puncture (CLP). Mice wer given 0.26 g/kg GA i.v. 1 hour post CLP. Results In MEF cells, 10 mM GA led to a 164% increase in HSP7 expression over control 4 hours post HS (P < 0.05 vs control Further, GA treatment led to an increase in cell survival post HS injury at all doses tested (P < 0.01 vs control). Following CLP induced sepsis, a single dose of GA led to an increase in lung an heart HSP70 at 1 and 2 hours post CLP vs saline control (SC). Thi effect was lost at 6 and 24 hours (see Figure 1, *P < 0.05 versu SC at each timepoint). Similarly, GA led to an increase in HSP70 i colon tissue as well, with the effect lasting to 6 hours (*P < 0.0 versus SC). The effect in colon was lost by 24 hours. Conclusions To our knowledge, this is the first report that show GA treatment can increase HSP70 expression both in vivo and i vitro. Previous data have demonstrated beneficial effects of GA treatment following ischemia/reperfusion injury and hemorrhagi shock early after injury. GA’s effect on HSP70 expression i multiple tissues may help to explain these effects. Further, GA’ effect on HSP70 expression may be an important factor involved i GA’s benefits in arthritis and joint disease. P25 Pharmacologic inhibition of cholinesterase improves survival in experimental sepsis S Hofer, C Eisenbach, I Lukic, L Schneider, E Martin, M Büchler, A Bierhaus, M Weigand University of Heidelberg, Germany Critical Care 2007, 11(Suppl 2):P25 (doi: 10.1186/cc5185) Introduction Lethal sepsis occurs if an excessive inflammator response evolves that cannot be controlled by physiological ant Figure 1 (abstract 24) Lung heat shock protein (HSP70) expression in glucosamine vs saline following cecal ligation and puncture. Figure 1 (abstract 24) Y Sakamoto1, K Mashiko1, H Matsumoto1, Y Hara1, Y Yamamoto2 1Chiba Hokusou Hospital, Nippon Medical School, Chiba, Japan; 2Department of Emergency Medicine, Nippon Medical School, Tokyo, Japan Critical Care 2007, 11(Suppl 2):P26 (doi: 10.1186/cc5186) Introduction High-mobility-group box protein 1 (HMGB1) is a highly conserved, ubiquitous protein present in the nuclei and cytoplasm of nearly all cell types and, secreted into the extracellular milieu, acts as a proinflammatory cytokine. The function of HMGB1 has been widely studied for sepsis and inflammation. HMGB1 was reported as a late mediator in endotoxic shock and was known as an abundant protein present in nuclei and cytoplasm and involved in maintaining nucleosome structure and regulation of gene transcription. Moreover, elevated, circulating levels of HMGB1 also have been described in a case of human hemorrhagic shock due to abdominal aortic aneurysm without evidence of infection. However, the relationship between HMGB1 and trauma has not been studied except for the report of a rat model of burn. Materials and methods The study cases consisted of 20 trauma patients who were admitted to the emergency room by ambulance. As soon as they arrived in the emergency room, their blood sample were collected, centrifuged, and stored at –80°C. The serum HMGB1 concentration was measured by ELISA. We compared the injury severity score (ISS), probability of survival values and the revised trauma score (RTS) of the patients with the presence of Introduction High-mobility-group box protein 1 (HMGB1) is a highly conserved, ubiquitous protein present in the nuclei and cytoplasm of nearly all cell types and, secreted into the extracellular milieu, acts as a proinflammatory cytokine. The function of HMGB1 has been widely studied for sepsis and inflammation. HMGB1 was reported as a late mediator in endotoxic shock and was known as an abundant protein present in nuclei and cytoplasm and involved in maintaining nucleosome structure and regulation of gene transcription. Moreover, elevated, circulating levels of HMGB1 also have been described in a case of human hemorrhagic shock due to abdominal aortic aneurysm without evidence of infection. However, the relationship between HMGB1 and trauma has not been studied except for the report of a rat model of burn. P26 Relationship between the presence of serum high- mobility-group box protein 1 and the injury severity score in trauma patients G s be e s a s a d jo d sease P25 Pharmacologic inhibition of cholinesterase improves survival in experimental sepsis S Hofer, C Eisenbach, I Lukic, L Schneider, E Martin, M Büchler, A Bierhaus, M Weigand University of Heidelberg, Germany Critical Care 2007, 11(Suppl 2):P25 (doi: 10.1186/cc5185) Introduction Lethal sepsis occurs if an excessive inflammatory Figure 1 (abstract 24) Lung heat shock protein (HSP70) expression in glucosamine vs saline following cecal ligation and puncture. Figure 1 (abstract 24) Aggressive and moderate fluid resuscitation in septic pigs: consequences on morbidity S Brandt, A Elftheriadis, T Regueira, H Bracht, J Gorrasi, J Takala, S Jakob University Hospital Inselspital, Bern, Switzerland Critical Care 2007, 11(Suppl 2):P28 (doi: 10.1186/cc5188) Results Our data showed that the number in group A was nine cases and group B was 11 cases. The ISS of group A was significantly higher than that in group B (P = 0.0013). The P value of group A was significantly lower than in group B (P = 0.0131). The serum HMGB1 level of the >25 ISS group was significantly higher than in the ≤25 ISS group. Introduction While early aggressive fluid administration has been associated with improved outcome in sepsis [1], this approach may increase the risk of lung edema and abdominal compartment syndrome when capillary permeability is increased. The aim of this study was to test two different approaches of volume resuscitation in septic animals. Discussion These data suggest that HMGB1 seems to be a primary mediator of trauma-induced pathology. Because the ISS was significantly correlated with the presence of serum HMGB1, HMGB1 may be expressed in severe injuries and it may be a important parameter that indicates the severity of injury. Methods Thirty pigs were anaesthetized and invasively monitored (systemic and regional flows and pressures). They were randomized to control, moderate volume (C; n = 7), control, high volume (CH; n = 8), peritonitis, moderate volume (P; n = 8) and peritonitis, high volume (PH; n = 7). Peritonitis was induced by instillation of 1 g/kg autologous faeces dissolved in glucose solution. Ventilation was adjusted to maintain an arterial pO2 >100 mmHg. Groups CH and PH received 15 ml/kg/hour Ringer’s solution plus 5 ml/kg/hour HES 6%, whereas groups C and P received 10 ml/kg/hour Ringer’s solution. If clinical signs of hypovolaemia were present, additional boluses of HES 6% (maximally 100 ml/hour) were given. The animals were treated and observed for 24 hours or until death. P28 serum HMGB1 (group A) and without the presence (group B). We therefore divided into two groups, high ISS group (≤25) and low ISS group (>25), and examined the relation with the serum HMGB1 level. Figure 1 (abstract 24) P25 Pharmacologic inhibition of cholinesterase improves survival in experimental sepsis S Hofer, C Eisenbach, I Lukic, L Schneider, E Martin, M Büchler, A Bierhaus, M Weigand University of Heidelberg, Germany Critical Care 2007, 11(Suppl 2):P25 (doi: 10.1186/cc5185) P25 Pharmacologic inhibition of cholinesterase improves survival in experimental sepsis S Hofer, C Eisenbach, I Lukic, L Schneider, E Martin, M Büchler, A Bierhaus, M Weigand University of Heidelberg, Germany Critical Care 2007, 11(Suppl 2):P25 (doi: 10.1186/cc5185) P25 Pharmacologic inhibition of cholinesterase improves survival in experimental sepsis S Hofer, C Eisenbach, I Lukic, L Schneider, E Martin, M Büchler, A Bierhaus, M Weigand University of Heidelberg, Germany Critical Care 2007, 11(Suppl 2):P25 (doi: 10.1186/cc5185) Materials and methods The study cases consisted of 20 trauma patients who were admitted to the emergency room by ambulance. As soon as they arrived in the emergency room, their blood sample were collected, centrifuged, and stored at –80°C. The serum HMGB1 concentration was measured by ELISA. We compared the injury severity score (ISS), probability of survival values and the revised trauma score (RTS) of the patients with the presence of Introduction Lethal sepsis occurs if an excessive inflammatory response evolves that cannot be controlled by physiological anti- S10 Available online http://ccforum.com/supplements/11/S2 Aggressive and moderate fluid resuscitation in septic pigs: consequences on morbidity P27 Beneficial effects of antiplatelet drugs in patients with community-acquired pneumonia and in endotoxin shock in mice J Winning1, J Baranyai1, R Claus1, I Eisenhut2, J Hamacher2, K Reinhart1, M Bauer1, W Lösche1 1University Hospital Jena, Germany; 2University Hospital Homburg, Germany Critical Care 2007, 11(Suppl 2):P27 (doi: 10.1186/cc5187) Results Cardiac output was higher in group PH as compared with the other groups (P < 0.05), while mean arterial pressure was Aims Systemic inflammation and sepsis are associated with blood platelet activation, which may contribute to the development of organ failure. In this study we proved whether antiplatelet drugs have a benefit in patients who may develop sepsis as well as in a mouse model of endotoxin shock. Figure 1 (abstract P28) Oxygenation index. Figure 2 (abstract P28) Survival proportion. Oxygenation index. Methods Data obtained from 224 patients with community- acquired pneumonia (CAP) were retrospectively analysed for an association between prehospital treatment with long-acting antiplatelet drugs such as acetyl salicylic acid (n = 36) or thienopyridine ADP-receptor antagonists (clopidogrel or ticlopidin, n = 8) and clinical outcome. Use of statins was an exclusion criterion. BALB/c mice were pretreated with clopidogrel for 4 days prior to an intraperitoneal injection of LPS (Escherichia coli 0111:B4). For platelet counts and blood gas analysis, standard procedures were used. Lung tissues were stained with HE or a FITC-labelled anti-fibrin(ogen) antibody. Results CAP patients with antiplatelet drugs (n = 44) were older than control patients (n = 180; 69 ± 7 vs 58 ± 13 years, P < 0.00001). At the day of hospital admission there were no differences in platelet or leukocyte counts, CRP and SOFA scores between both groups. However, patients on antiplatelet drugs developed organ failure less frequently than control patients (ICU admission: 9.1% vs 26.1%; P < 0.02). In the mouse model of endotoxin shock, clopidogrel reduced the drop in platelet count and the degree of lung injury. Compared with controls we found 20 hours after LPS injection in the clopidogrel-treated animals a lower number of thrombi in the lung vasculature (6.1 ± 2.3 vs 11.5 ± 4.4 thrombi per screen, P < 0.025) as well as higher blood pH and bicarbonate levels (7.01 ± 0.01 vs 6.93 ± 0.04, P < 0.04 and 10.2 ± 0.14 vs 7.3 ± 0.14 mmol/l, P < 0.03, respectively). P29 Effects of volume resuscitation on hepatosplanchnic oxygen consumption, liver mitochondrial function and mortality in endotoxemia Multiple studies have stressed the importance of the contribution of activated complement to the pathology of reperfusion injury after tissue ischemia. Using intravital microscopy, this study explores functional consequences of the inhibition of the classical pathway of complement activation with C1-esterase inhibitor (C1-INH) in the context of superior mesenteric artery occlusion (SMAO)/ reperfusion. T Regueira1, E Borotto1, S Brandt2, H Bracht1, J Gorrasi1, P Lepper1, J Takala1, S Jakob1 1Intensive Care Medicine and 2Department of Anesthesiology, University Hospital, Bern, Switzerland Critical Care 2007, 11(Suppl 2):P29 (doi: 10.1186/cc5189) Thirty anesthetized, spontaneously breathing, male Sprague– Dawley rats underwent SMAO for 60 minutes followed by reperfusion (4 hours). C1-esterase inhibitor (100 IU/kg, 200 IU/kg body weight) or saline (0.9%) was given as a single bolus before reperfusion. Sham-operated animals (n = 10) without SMAO served as controls. Systemic hemodynamics were monitored continuously, arterial blood gases analyzed intermittently, and leukocyte/ endothelial interactions in the mesenteric microcirculation quantified at intervals using intravital microscopy. Ileal lipid-binding protein (I-LBP) levels were measured from serum samples with an ELISA at the end of the experiments. Introduction Fluid resuscitation is necessary in sepsis, but positive fluid balance may increase the risk of mortality. We tested the hypothesis that a volume resuscitation strategy may modify liver mitochondrial function and outcome. Methods Twenty-nine anesthetized pigs received for 24 hours either endotoxin or placebo, and either Ringer’s lactate 10 ml/kg/hour or 15 ml/kg/hour + 5 ml/hour HES. Systemic and regional hemo- dynamics were measured. Liver mitochondrial state 3 and state 4 oxygen consumption were determined. Results Hepatosplanchnic oxygen delivery was similar in endotoxic pigs with high (2.97 ± 1.58 ml/min/kg) vs moderate volume administration (3.06 ± 0.6 ml/min/kg), but hepatosplanchnic VO2 was lower in animals with high (1.32 ± 0.4 ml/min/kg) vs moderate volume administration (1.75 ± 0.3 ml/min/kg, P = 0.019). Endotoxin high-volume pigs exhibited a decrease in state 3 respiration for complex I and complex II (not significant) in comparison with control high-volume and with endotoxin low-volume pigs (Figure 1). They also had an increased mortality rate during the 24-hour study period (60% vs 0% in controls). C1-INH restored microcirculatory perfusion of postcapillary venules to baseline levels in a dose-dependent manner and reduced leukocyte adhesion following SMAO/reperfusion to similar levels in both C1-INH-treated groups during reperfusion. P29 Furthermore, C1- INH treatment efficiently prevented metabolic acidosis, and reduced the need for intravenous fluids to support blood pressure. Furthermore, I-LBP levels decreased in a dose-dependent manner, and were comparable with the levels of sham-operated animals at the end of the experiments. Survival rates were 100% in controls and after 200 IU/kg C1-INH, 90% after 100 IU/kg C1-INH, and 30% in saline-treated animals. Conclusion A prolonged high-volume resuscitation approach during endotoxemia may be associated with impaired hepato- splanchnic oxygen consumption, liver mitochondrial dysfunction In the setting of mesenteric ischemia, C1-INH given as a bolus infusion shortly before reperfusion efficiently restored microcirculatory perfusion in a dose-dependent manner, reduced local and systemic inflammatory response, and improved outcome. I-LBP levels correlated well with the functional consequences of mesenteric ischemia/reperfusion and treatment at the end of the experiments. Figure 2 (abstract P28) S Figure 2 (abstract P28) Survival proportion. Conclusions Antiplatelet drugs may have a beneficial effect in systemic inflammation and sepsis, and could be a novel therapy option, at least in patients of low bleeding risk. One mechanism of their effects could be a reduction in the microvascular thrombus formation. Conclusions Antiplatelet drugs may have a beneficial effect in systemic inflammation and sepsis, and could be a novel therapy option, at least in patients of low bleeding risk. One mechanism of their effects could be a reduction in the microvascular thrombus formation. Survival proportion. S11 cal Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine and high mortality. The impact of aggressive and prolonged volume administration on hepatosplanchnic oxygenation and mitochondrial function in human sepsis should be determined. similar in all groups. While the oxygenation index (paO2/FiO2) decreased in all groups, group PH had the lowest values after 6 hours and throughout the rest of the experiments (P < 0.05) (Figure 1). Survival was lowest in group PH, followed by group P, while all animals in the control groups survived until 24 hours (Figure 2). Conclusion High-volume administration decreased oxygenation and survival in peritonitis but not in control animals. A high-volume approach may not be generally beneficial in abdominal sepsis. Reference 1. Rivers E, et al.: N Engl J Med 2001, 345:1368-1377. Effect of C1-esterase inhibitor treatment on microcirculatory perfusion after superior mesenteric artery ischemia Effect of C1-esterase inhibitor treatment on microcirculatory perfusion after superior mesenteric artery ischemia M Lauterbach, G Horstick, N Plum, J Lotz, E Lauterbach, L Weilemann, O Kempski University Hospital Mainz, Germany Critical Care 2007, 11(Suppl 2):P30 (doi: 10.1186/cc5190) 1. Rivers E, et al.: N Engl J Med 2001, 345:1368-1377. Figure 1 (abstract P29) 12 inflammatory response, and improved outcome. I-LBP levels correlated well with the functional consequences of mesenteric ischemia/reperfusion and treatment at the end of the experiments. P31 Dobutamine protects lymphocyctes against staurosporin- induced apoptosis via a receptor-independent and p38- independent pathway F Jans1, T Piegeler2, R De Jongh1, R Heylen1, T Loop2, M Roesslein2 1Ziekenhuis Oost-Limburg, Genk, Belgium; 2University Hospital, Freiburg, Germany Critical Care 2007, 11(Suppl 2):P31 (doi: 10.1186/cc5191) Introduction Since catecholamines have been shown to modulate various immunological functions, the goal of this work was to investigate their effects on staurosporin-induced apoptosis of Jurkat T cells, a well-established model for human T lymphocytes. Figure 1 (abstract P29) P30 Conclusion High-volume administration decreased oxygenation and survival in peritonitis but not in control animals. A high-volume approach may not be generally beneficial in abdominal sepsis. Reference Serum vasopressin concentrations in critically ill patients in the intensive care unit A Melissaki, A Efthymiou, T Kyriakopoulou, G Kribeni, E Evaggelaki, A Tsikali, D Andreopoulos, A Zaglis, N Baziotis Saint Savvas General Hospital, Athens, Greece Critical Care 2007, 11(Suppl 2):P32 (doi: 10.1186/cc5192) Introduction The aim of the study is the measurement of serum vasopressin concentrations in the mixed critically ill patients, 24 hours after admission to the ICU and just before the discharge. Methods In this study there were included patients admitted to the ICU from June until November 2006 (n = 22; 12 males, 10 females), mean age 46.45 ± 22.03, APACHE II score 8.59 ± 4.76, length of stay 9.68 ± 6.52. Patients with central nervous system failure, neurosurgical patients and patients remaining in the ICU for no longer than 72 hours were excluded. Serum vasopressin concentrations were measured 24 hours after their admission to the ICU and just before their discharge. The control group was 20 healthy volunteers (blood donors). Vasopressin was measured by the radioimmunoassay method in pmol/l. The sensitivity of the method is 0.5 pmol/l and the specificity is 100%. The statistical analysis was done with the t test. Conclusions In catecholamine-dependent human septic shock, terlipressin (with and without concomitant dobutamine) stabilizes hemodynamics and reduces norepinephrine requirements. Dobutamine is a useful inotropic agent to reverse the depression in global oxygen transport resulting from sole terlipressin infusion without obvious side effects. Dobutamine protects lymphocyctes against staurosporin- induced apoptosis via a receptor-independent and p38- independent pathway F Jans1, T Piegeler2, R De Jongh1, R Heylen1, T Loop2, M Roesslein2 1Ziekenhuis Oost-Limburg, Genk, Belgium; 2University Hospital, Freiburg, Germany Critical Care 2007, 11(Suppl 2):P31 (doi: 10.1186/cc5191) Introduction Since catecholamines have been shown to modulate various immunological functions, the goal of this work was to investigate their effects on staurosporin-induced apoptosis of Jurkat T cells, a well-established model for human T lymphocytes. Introduction Since catecholamines have been shown to modulate various immunological functions, the goal of this work was to investigate their effects on staurosporin-induced apoptosis of Jurkat T cells, a well-established model for human T lymphocytes. S12 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Methods Jurkat T cells passages 1–12 were used. Apoptosis was measured with a caspase-activity assay and with FACS analysis of annexin–propidium iodide double-stained cells. than the value on admission and it approaches the value of vasopressin in healthy volunteers. To confirm these results, more studies will be needed. than the value on admission and it approaches the value of vasopressin in healthy volunteers. To confirm these results, more studies will be needed. p p Results Exposure of Jurkat T cells for 2 hours to staurosporin (2 µM) induced apoptosis: the number of apoptotic cells increased to 14.0 ± 0.8% versus 2.3 ± 0.4% in the control group. Pre- treatment (4 hours) with dobutamine 100 and 500 µM decreased the staurosporin-induced apoptosis to 11.6 ± 0.6% and 8.7 ± 0.7%, respectively (P < 0.01, mean ± SEM, n = 44). Other catechol- amines like epinephrine and norepinephrine (both up to 500 µM) had no effect on staurosporin-induced apoptosis. To investigate whether this protective effect of dobutamine was mediated via β- receptors, specific β-blockers were used: neither atenolol (β1) (100 mM), nor ICI 118,551 (β2) (10 mM) blocked the protective effect of dobutamine. Furthermore, dobutamine (1–500 µM) did not increase cAMP production in these cells. Therefore, the protective effect of dobutamine is not β-receptor-mediated. Since it was previously demonstrated that MAPKs p38 and JNK, but not ERK, are activated by dobutamine in Jurkat T cells, we investigated whether the activation of these MAPKs are involved in the protection by dobutamine: inhibition of JNK activation with SP 600125 (1 µM) did not influence the protective effect of dobuta- mine. Inhibition of p38 activation with SBI 202190 (5 µM) even seemed to reinforce the protection afforded by dobutamine. Effects of simultaneously infused terlipressin and dobutamine in septic shock Effects of simultaneously infused terlipressin and dobutamine in septic shock A Morelli1, C Ertmer2, M Lange2, K Broeking2, A Orecchioni1, M Rocco1, H Van Aken2, P Pietropaoli1, M Westphal2 1University of Rome ‘La Sapienza’, Rome, Italy; 2University Hospital of Muenster, Germany Critical Care 2007, 11(Suppl 2):P33 (doi: 10.1186/cc5193) Introduction Terlipressin is increasingly used in the treatment of sepsis-associated hypotension. However, terlipressin may reduce cardiac output and global oxygen supply. Introduction Terlipressin is increasingly used in the treatment of sepsis-associated hypotension. However, terlipressin may reduce cardiac output and global oxygen supply. Methods We performed a prospective, randomized, controlled clinical study to determine whether dobutamine may counter- balance the depressions in cardiac index and mixed-venous oxygen saturation resulting from sole terlipressin infusion. We enrolled 60 septic shock patients requiring high doses of norepinephrine (0.9 µg/kg/min) to maintain mean arterial pressure at 70 ± 5 mmHg. Patients were randomly allocated to be treated either with (a) 1 mg terlipressin, (b) 1 mg terlipressin followed by incremental dobuta- mine doses to reverse the anticipated reductions in mixed-venous oxygen saturation, or (c) sole norepinephrine infusion (control; each n = 20). Conclusions These experiments demonstrate that dobutamine pretreatment protects T cells from staurosporin-induced apoptosis. This protective effect is not β-receptor-mediated. Also, activation of MAPKs p38 or JNK by dobutamine is not responsible for the protective effect. The molecular mechanisms by which dobutamine exerts this protective effect remain to be elucidated. Results Data from right heart catheterization, thermo-dye dilution catheter, gastric tonometry, as well as organ function and coagulation were obtained at baseline and after 2 and 4 hours. Terlipressin (with and without dobutamine) infusion preserved the mean arterial pressure at threshold values of 70 ± 5 mmHg, while allowing one to reduce norepinephrine doses to 0.18 ± 0.04 and 0.2 ± 0.05 µg/kg/min, respectively (vs 1.4 ± 0.07 µg/kg/min in controls at 4 hours; each P < 0.01). The terlipressin-linked decrease in mixed-venous oxygen saturation was reversed by dobutamine (at 4 hours: 59 ± 2 vs 69 ± 3%, P = 0.023). No statistically significant differences were found intra-group and between groups in terms of differences between gastric mucosal and arterial carbon dioxide partial pressure, blood clearance of indocyanine green, as well as the plasma disappearance rate of indocyanine green P32 Serum vasopressin concentrations in critically ill patients in the intensive care unit Serum vasopressin concentrations in critically ill patients in the intensive care unit Vasopressin substitution causes microcirculatory changes in patients with septic shock Vasopressin substitution causes microcirculatory changes in patients with septic shock S Klinzing, C Reinhard, T Simon, T Schürholz, Y Sakr, K Reinhart, G Marx Friedrich Schiller Universität, Jena, Germany Critical Care 2007, 11(Suppl 2):P34 (doi: 10.1186/cc5194) Results Vasopressin serum concentrations at 24 hours after admission were 32,618 ± 20,570 pmol/l. Vasopressin serum concentrations in critically ill patients were significantly higher than in the healthy control group (11,302 ± 31,002, P < 0.001). Serum vasopressin concentrations on admission compared with vaso- pressin concentrations at discharge were statistically significantly increased (P < 0.001). Introduction We tested the effects of arginine vasopressin on tissue oxygenation, microvascular reactivity and oral mucosa microcirculation in patients with septic shock. Conclusions Serum vasopressin concentrations in critically ill patients in a mixed ICU are increased 24 hours after admission compared with the control group. The value at discharge is lower Methods In 20 patients with septic shock, tissue microcirculation was determined before treatment with AVP (2 IU/hour), after 2 hours of treatment and 2 hours after treatment. S13 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine Table 1 (abstract P34) Base level 2 hours AVP 2 hours after AVP P value step 1 P value step 2 SO2 1 mm (%) 79; 40–99 72.5; 59–88 83; 45–93 <0.05 <0.05 SO2 4 mm (%) 79; 48–97 68; 50–93 81; 24–99 <0.05 <0.01 Flow 1 mm 56; 11–390 33; 10–212 39; 10–249 <0.01 <0.01 Flow 4 mm 332.5; 149–517 280; 119–511 331; 150–581 <0.05 <0.05 Velocity 1 mm 22.5; 12–45 17.5; 11–33 20; 11–33 <0.01 <0.05 The thenar muscle StO2 was measured by near-infrared spectroscopy (InSpectra; Hutchinson Technology, Hutchinson, MN, USA). Oral mucosal tissue oxygen saturation, microcirculatory blood flow and blood flow velocity were measured in depths of 1 and 4 mm with a laser Doppler flowmetry and remission spectroscopy system (O2C). Methods Sixteen ewes were chronically instrumented to determine the hemodynamics of the systemic and pulmonary circulation. After 16 hours of endotoxin infusion, all sheep exhibited a hypotensive– hyperdynamic circulation. Thereafter, the animals were randomized to be treated with either a continuous (2 mg over 24 hours) or bolus infusion (1 mg every 6 hours) of terlipressin. y y 2 Results See Table 1. Rebound hypotension following terlipressin bolus infusion can be prevented by continuous low-dose infusion of terlipressin Rebound hypotension following terlipressin bolus infusion can be prevented by continuous low-dose infusion of terlipressin Vasopressin substitution causes microcirculatory changes in patients with septic shock Vasopressin infusion led to a significant decrease of oral mucosal oxygen saturation and blood flow, and a significant decrease of flow velocity in a depth of 1 mm. Changes in thenar tissue perfusion were not detectable. Results Continuous infusion of terlipressin reversed the endotoxin- induced decrease in MAP during the entire 24-hour study period (P < 0.001). Intermittent bolus injections of terlipressin contributed to overshooting increases in MAP, as well as in systemic and pulmonary vascular resistance index (each P < 0.001), which were followed by sudden and strong rebound effects (Figure 1). Conclusion Vasopressin causes a deterioration of oral mucosal blood flow but not in thenar tissue perfusion. Conclusion A goal-directed continuous infusion of terlipressin may be superior to terlipressin bolus injection to treat patients with sepsis-related arterial hypotension. Apparent heterogenity in splanchnic vascular response to norepinephrine during sepsis M Lange1, K Bröking1, C Ertmer1, D Traber2, C Hucklenbruch1, H Van Aken1, M Westphal1 1University of Münster, Germany; 2The University of Texas Medical Branch, Galveston, TZ, USA Critical Care 2007, 11(Suppl 2):P35 (doi: 10.1186/cc5195) J Gorrasi1, V Krejci2, L Hiltebrand2, S Brand2, H Bracht1, B Balsiger3, J Takala1, S Jakob1 1Department of Intensive Care Medicine, 2Department of Anesthesia and 3Departament of Gastroenterology, University Hospital Bern, Switzerland Critical Care 2007, 11(Suppl 2):P36 (doi: 10.1186/cc5196) Introduction Bolus infusion of terlipressin, a vasopressin analog, increases the mean arterial pressure (MAP) in patients with sepsis- related arterial hypotension. However, bolus infusion of terlipressin may be associated with severe side effects like excessive systemic and pulmonary vasoconstriction. We hypothesized that continuous low-dose infusion of terlipressin may reverse arterial hypotension with reduced side effects. Introduction Sepsis alters vascular reactivity. We studied the impact of peritonitis and endotoxemia on hepatic and superior mesenteric arterial contractility. Materials and methods We studied fecal peritonitis (P, n = 7), endotoxin-infusion (E, n = 8) and control (C, n = 6) for 24 hours after abdominal surgery and eight control pigs without surgery (SPA). Systemic and regional hemodynamics and ex-vivo splanchnic vascular reactivity to norepinephrine (NE; tissue bath) were measured and cumulative dose–response curves to NE were constructed. Tension was expressed in grams. Figure 1 (abstract P35) Figure 1 (abstract P35) Figure 1 (abstract P35) Figure 1 (abstract P35) Mean arterial pressure (MAP) during continuous and intermittent bolus infusion of terlipressin in endotexemic ewes. g Results CO increased (P < 0.05) in P and E. SMA flow (median (range)) decreased in C from 24 (15–30) to 15 (11–21) ml/kg/min (P = 0.022) (Table 1). Table 1 (abstract P36) N of arterial rings SMA (g) HA (g) C (17) 3 (2–4) 2 (1–3) P (21) 3 (2–4) 3 (2–4) E (17) 1 (0.3–2)*;‡ 2 (1–3) SPA (18) 10 (8–16)**,† 8 (7–10)**,† Data presented as median (range). *P = 0.002 E vs P and C; **P < 0.01 vs C, P, and E; †P < 0.001 vs C, E and P; ‡P = 0.008 vs C. Effect of norepinephrine on cardiac output and preload in septic shock patients Effect of norepinephrine on cardiac output and preload in septic shock patients Methods With ethics committee approval, 10 male Sprague– Dawley rats were studied. Anesthesia was induced with alfaxalone and maintained with isofluorane. Mechanical ventilation was performed via tracheostomy. All rats received 0.9% NaCl 3 ml/hour via a carotid line. Immediately after baseline assessment (T = 0), rats received 1 ml/kg i.v. infusion over 30 minutes (study group (n = 5), endotoxin 10 mg/ml (Escherichia coli O55:B5; Sigma, MO, USA); control group, 0.9% NaCl). Echocardiography was performed (15 MHz transducer, Vivid5; GE Healthcare) at T = 0, 60 minutes (T = 60) and 2.5 hours (T = 150). Measurements included the heart rate, mean arterial pressure (MAP), femoral venous pressure, LV outflow tract diameter and flow (peak velocity (Vpeak), cardiac output (CO)), peak early diastolic mitral inflow (E), peak systolic mitral annulus velocity (S′) and E′. O Hamzaoui, H Ksouri, C Richard, J Teboul Bicetre Hospital, Le Krêmlin Bicetre, France Critical Care 2007, 11(Suppl 2):P37 (doi: 10.1186/cc5197) Introduction Norepinephrine (NE) is a first-line vasopressor used in patients with septic shock. Because of its predominant α- agonist effect, it is assumed to increase vasomotor tone and hence the mean arterial pressure (MAP) without significant effect on the cardiac index (CI). However, a potential beneficial effect on CI can be expected from its venoconstrictor α-agonist-mediated effect combined with an inotropic β1 agonist effect, provided that the increase in left ventricular afterload is not excessive (high levels of MAP). The aim of our study was to examine the cardiovascular effect of NE when it induces marked changes in MAP. Results There was no significant difference in mean ± SD weight (study 539 ± 88 g, control 504 ± 108 g, P = 0.6) or hemodynamic variables at T = 0. At T = 60, only Vpeak was higher in the study group compared with controls (1.29 ± 0.24 vs 0.86 ± 0.21 m/s, P = 0.03). The study group demonstrated lower MAP, E and E′ at T = 150 (Table 1). Methods In an observational study of patients (n = 37) resuscitated for septic shock, we analysed hemodynamic PiCCO data at two consecutive time points where the MAP changed by more than 15% in response to either initiation or to change of doses of NE. Two subgroups of patients were identified. P39 Hemodynamic and cardiac peptide in septic myocardial depression: the effects of calcium sensitizer Hemodynamic and cardiac peptide in septic myocardial depression: the effects of calcium sensitizer C Cariello, F Guarracino, L Giannecchini, P Giomi, S Lorenzini University Hospital, Pisa, Italy Critical Care 2007, 11(Suppl 2):P39 (doi: 10.1186/cc5199) Introduction The aim of this retrospective study is to evaluate hemodynamic and neurohormonal effects of levosimendan in cardiac patients with sepsis-induced cardiac dysfunction. Septic shock is characterized by profound cardiovascular alterations including myocardial depression. Levosimendan has recently been shown to improve cardiac function in septic shock. Conclusion In our septic shock patients, changes in MAP resulting from increases or decreases in the doses of NE, were associated with changes in CI related to changes in GEDVi (cardiac preload) and in some patients to changes in systolic left ventricular function evaluated by GEF. These findings suggest that administration of NE in septic shock is associated not only with an increase in MAP but also with an increase in systemic blood flow. Methods Fifteen patients with myocardial depression related to septic shock were enrolled. All patients had SIRS criteria, culture isolation of one or more pathogens, positive procalcitonin, SBP < 90 mmHg unresponsive to load challenge. We defined myo- cardial depression as a reduced SvO2 in the presence of increased brain natriuretic peptide secretion and Troponin I release, and systolic and/or diastolic dysfunction by transoesophageal echo evaluation of ejection fraction and mitral annulus tissue Doppler imaging velocities. All patients received levosimendan infusion for 24 hours at 0.1 µg/kg/min combined with norepinephrine. Effect of norepinephrine on cardiac output and preload in septic shock patients The first subgroup (MAPincr) consisted of 21 patients in whom the MAP increased by more than 15% in response to either initiation of NE infusion (n = 8) or increase in NE dose (from 1.7 ± 1.7 to 2.2 ± 1.4 mg/hour; n = 13). The second subgroup (MAPdecr) consisted of 16 patients in whom the MAP decreased by more than 15% in response to the decrease in NE doses. For both subgroups, the time between the two consecutive sets of measurements did not exceed 2 hours and no other treatments that may alter hemodynamics were adminis- tered within this period (fluids, hemofiltration, diuretics or other catecholamines). Table 1 (abstract P38) Control Study P MAP (mmHg) 118 ± 21 75 ± 35 0.05 CO (l/min) 0.156 ± 0.02 0.181 ± 0.07 0.5 E (m/s) 1.02 ± 0.2 0.76 ± 0.11 0.04 E′ (m/s) 0.095 ± 0.02 0.061 ± 0.02 0.03 Conclusion In this model, endotoxemia was associated with a decrease in E and E′. This decrease in E′ suggests a decreased rate of myocardial relaxation. This has not previously been reported. Results In the MAPincr subgroup, MAP increased from 56 ± 17 to 84 ± 12 mmHg (P < 0.05) while significant increases in CI (from 3.4 ± 1.0 to 3.7 ± 0.9 l/min/m2), stroke volume index (SVi) (from 37 ± 12 to 41 ± 11 ml/m2) and global end diastolic volume index (GEDVi) (from 706 ± 203 to 767 ± 225 ml/m2) were observed. Neither the heart rate nor the global ejection fraction (GEF) signifi- cantly changed. In seven patients, the GEF markedly increased by >15% in parallel to the increase in SVi. In the MAPdecr subgroup, MAP decreased from 95 ± 12 to 70 ± 9 mmHg (P < 0.05). The CI (from 3.5 ± 1.4 to 3.0 ± 0.9 l/min/m2) and GEDVi (from 815 ± 319 to 721 ± 253 ml/m2) decreased significantly, while the heart rate, SVi (P = 0.07) and GEF did not change. Table 1 (abstract P36) Mean arterial pressure (MAP) during continuous and intermittent bolus infusion of terlipressin in endotexemic ewes. Conclusions The splanchnic vascular response to NE is heterogenous in sepsis, and SMA is most affected. This may modify blood flow distribution if high NE doses are used. S14 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 P37 endotoxemia. This study sought to determine the effect of endotoxemia upon TDI variables. P42 A network system for the treatment of pediatric septic shock M Sasse1, M Kirschstein2, H Köditz1, K Seidemann1, A Wessel1 1Medical University Children’s Hospital, Hannover, Germany; 2Children Hospital AKH Celle, Germany Critical Care 2007, 11(Suppl 2):P42 (doi: 10.1186/cc5202) M Sasse1, M Kirschstein2, H Köditz1, K Seidemann1, A Wessel1 1Medical University Children’s Hospital, Hannover, Germany; 2Children Hospital AKH Celle, Germany Critical Care 2007, 11(Suppl 2):P42 (doi: 10.1186/cc5202) Introduction We show the effect of a network system in the treatment of pediatric septic shock, especially for children with Waterhouse–Friderichsen syndrome. In 2003 we founded a pediatric intensive care network with 15 children’s hospitals in Lower Saxony, Germany. The aims were the standardisation of clinical therapies, implementation of training programs and the installation of an emergency system in the region of lower Saxony. Introduction We show the effect of a network system in the treatment of pediatric septic shock, especially for children with Waterhouse–Friderichsen syndrome. In 2003 we founded a pediatric intensive care network with 15 children’s hospitals in Lower Saxony, Germany. The aims were the standardisation of clinical therapies, implementation of training programs and the installation of an emergency system in the region of lower Saxony. Methods The first standard was implemented for the treatment of the Waterhouse–Friderichsen syndrome. At first, we started with the educational program. The program included different central symposia about septic shock in children. The second step was the standardisation of the diagnosis and the therapy, including the administration of human protein C concentrate (PC), and the clinical pathways. We implemented a round-the-clock emergency system with the possibility for transportation of critically ill patients, permanent consultation of the tertiary medical center and onsite treatment through the tertiary center staff if the patient could not be transferred. All patients were announced to the tertiary medical Results Spontaneous oxidative burst activity in group H increased significantly from baseline (30.19 ± 4.79) to H (57.45 ± 9.86) and 60H (56.26 ± 14.64) (P < 0.01) while the control group did not present significant variation. Between groups there were significant differences at H (ANH = 57.45 ± 9.86; control = 23.18 ± 7.16; P = 0.0007), 60H (ANH = 56.26 ± 14.64; control = 34.53 ± 9.06; P = 0.0225), 120H (ANH = 43.59 ± 5.46; control = 28.65 ± 10.44; P = 0.0220) and 60BI (ANH = 38.60 ± 1.85; control = 25.59 ± 8.12; P = 0.0082). Table 1 (abstract P41) Introduction In recent years there has been increasing evidence that a resuscitation strategy with different fluids can have widely divergent impacts on the immune response, neutrophil activation and tissue injury. This prospective study was undertaken to determine the neutrophil oxidative burst in the swine model during an acute normovolemic hemodilution (ANH) procedure with hydroxyethyl starch. Methods Twelve pigs were anesthetized, instrumented and randomized into two groups: control and hemodilution (H). The control group was only anesthetized and instrumented while animals in the ANH group were submitted to acute normovolemic hemodilution to a target hematocrit of 15% with volume replacement performed with hydroxyethyl starch 130/0.4 at a 1:1 ratio. The withdrawn blood was returned to the animals 120 minutes after the end of hemodilution. Neutrophil oxidative burst was performed with blood samples collected at the femoral vein at the following time points: before ANH (baseline), after instrumentation (INST), immediately after ANH (H), 60 minutes after ANH (60H), 120 minutes after ANH (120H), 60 minutes after blood infusion (60BI) and 120 minutes after blood infusion (120BI), and determined with a flow cytometer. Spontaneous and stimulated oxidative burst activation of neutrophils were performed with dichlorofluorescein diacetate and phorbol myristate acetate. Statistical analyses were performed using one-way analysis of variance followed by a Dunnett test or t test. A P value of 0.05 was considered statistically significant. Tissue Doppler imaging suggests an association between endotoxemia and impaired myocardial relaxation D Sturgess, B Haluska, B Venkatesh University of Queensland, Brisbane, Australia Critical Care 2007, 11(Suppl 2):P38 (doi: 10.1186/cc5198) D Sturgess, B Haluska, B Venkatesh University of Queensland, Brisbane, Australia Critical Care 2007, 11(Suppl 2):P38 (doi: 10.1186/cc5198) Results Data were obtained by evaluating the average of the percentage variation between T0 (starting infusion) and T1 (24 hours after infusion), T2 (48 hours), T3 (72 hours), T4 (96 hours), T5 (120 hours) and T6 (144 hours). Levosimendan significantly increased SvO2 and ejection fraction, and decreased Introduction Tissue Doppler imaging (TDI) is a novel technique that measures myocardial velocity. The peak early diastolic mitral annulus velocity (E′) offers a relatively preload-insensitive measure of LV relaxation. There are scant data regarding its use in sepsis or Introduction Tissue Doppler imaging (TDI) is a novel technique that measures myocardial velocity. The peak early diastolic mitral annulus velocity (E′) offers a relatively preload-insensitive measure of LV relaxation. There are scant data regarding its use in sepsis or S15 Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine Troponin I and brain natriuretic peptide. Levosimendan improved diastolic function by increasing the E′ velocity at tissue Doppler imaging at 48 hours. All data were analysed by the Fisher F test. Troponin I and brain natriuretic peptide. Levosimendan improved diastolic function by increasing the E′ velocity at tissue Doppler imaging at 48 hours. All data were analysed by the Fisher F test. P41 P40 P40 Neutrophil oxidative burst evaluation during acute normovolemic hemodilution: preliminary results M Kahvegian, D Tabacchi Fantoni, DA Otsuki, C Holms, C Oliveira Massoco, J Costa Auler Jr University of São Paulo Medical School, São Paulo, Brazil Critical Care 2007, 11(Suppl 2):P40 (doi: 10.1186/cc5200) Neutrophil oxidative burst evaluation during acute normovolemic hemodilution: preliminary results Table 1 (abstract P41) IL-12 (pg/ml) TSH (mIU/l) fT3 (pg/ml) fT4 (ng/dl) Control group 4.8 ± 2.1 2.25 ± 2.1 2.93 ± 0.5 1.18 ± 0.14 Septic patients 19.05 ± 10.7 1.173 ± 1.85 1.56 ± 0.6 1.06 ± 0.3 P <0.001 0.001 <0.001 0.118 Conclusion According to our findings, IL-12 has a role in HPT dysfunction in most critically ill patients. Relationship of IL-12 and thyroid indices in sepsis Relationship of IL-12 and thyroid indices in sepsis E Karakoc, I Karayaylali, T Sunbul Cukurova University, Adana, Turkey Critical Care 2007, 11(Suppl 2):P41 (doi: 10.1186/cc5201) Table 1 (abstract P39) T0 T1 T2 T3 T4 T5 T6 SvO2 (%) 0 4 10 17 22 19 22 Trop I (ng/ml) 0 –65 –86 –82 –78 –62 –62 BNP (%) 0 –45 –41 –56 –50 –42 –44 E′ (cm/s) <8 >8 >8 >8 >8 >8 >8 EF (%) <30 >40 >40 >40 >40 >40 >40 Conclusions Levosimendan seems to improve systemic hemodynamics and neurohormonal cardiac function in patients with septic cardiac dysfunction. Introduction Sickeuthroid syndrome is very frequent in critically ill patients. Cytokines may have a role in this syndrome. IL-12 is involved in the central regulation of the hypothalamic–pituitary– thyroid (HPT) axis during illness. The aim of this study is to evaluate the relationship of IL-12 and thyroid functions in septic patients. Introduction Sickeuthroid syndrome is very frequent in critically ill patients. Cytokines may have a role in this syndrome. IL-12 is involved in the central regulation of the hypothalamic–pituitary– thyroid (HPT) axis during illness. The aim of this study is to evaluate the relationship of IL-12 and thyroid functions in septic patients. Materials and methods Twenty-four septic patients and 18 healthy controls were enrolled into the study with the mean ages of 49.9 ± 20.6 and 45.8 ± 22.3 years, respectively. Hyperthyroid and hypothyroid patients were excluded. Free triiodothyronine (fT3), free thyroxine (fT4) and TSH were measured simultaneously with IL-12. Materials and methods Twenty-four septic patients and 18 healthy controls were enrolled into the study with the mean ages of 49.9 ± 20.6 and 45.8 ± 22.3 years, respectively. Hyperthyroid and hypothyroid patients were excluded. Free triiodothyronine (fT3), free thyroxine (fT4) and TSH were measured simultaneously with IL-12. Results The mean IL-12, fT3, fT4 and TSH values of septic patients and the control group are presented in Table 1. IL-12 was significantly higher in septic patients (19.05 ± 10.7 pg/ml vs 4.8 ± 2.0 pg/ml, P < 0.005). fT3 and TSH values were significantly low in septic patients. There was a significantly strong correlation between IL-12 and fT4 in septic patients but not fT3 and TSH (r = 0.88, P = 000). There was no correlation between IL-12 and other thyroid indices in the control group. P44 Optimization of antibacterial treatment in pediatric intensive care units using procalcitonin center directly after admission into the network hospitals. The final step was the presentation of the project in the different hospitals. Results We treated 10 children with Waterhouse–Friderichsen syndrome in the network. Three of them were attended on site and seven were transferred in the tertiary center. The announcement time in eight cases was 15 minutes–1 hour. Primarily, a consultation was accomplishing routinely. The transportation team of the tertiary center continued the treatment on site and afterwards in the center. All patients showed typical signs of Waterhouse–Friderichsen syndrome with purpura fulminans and severe multiorgan failure. No patient died and only one patient had necrosis of the skin, which existed already at admission. The others had a restitution ad integrum. No adverse effects were observed with the PC concentrate administration. center directly after admission into the network hospitals. The final step was the presentation of the project in the different hospitals. Results We treated 10 children with Waterhouse–Friderichsen syndrome in the network. Three of them were attended on site and seven were transferred in the tertiary center. The announcement time in eight cases was 15 minutes–1 hour. Primarily, a consultation was accomplishing routinely. The transportation team of the tertiary center continued the treatment on site and afterwards in the center. All patients showed typical signs of Waterhouse–Friderichsen syndrome with purpura fulminans and severe multiorgan failure. No patient died and only one patient had necrosis of the skin, which existed already at admission. The others had a restitution ad integrum. No adverse effects were observed with the PC concentrate administration. N Beloborodova1, D Popov1, M Traube2, E Ochakovskaya1, E Chernevskaya1 1Bakoulev Scientific Center for Cardiovascular Surgery, Moscow, Russian Federation; 2Filatov Children’s Hospital, Moscow, Russia Federation Critical Care 2007, 11(Suppl 2):P44 (doi: 10.1186/cc5204) Introduction Neonates and infants in the ICU are at high risk of severe infections and sepsis. Often it is not easy to diagnose sepsis based only on clinical findings; reliable biomarkers are needed to prove the diagnosis. Conclusions The network system and the standard treatment with PC worked without severe problems. The survival rate and the outcome in our small study group were excellent. Our experience allows us to enlarge the system on other diseases. Objective To study the value of procalcitonin (PCT) as a marker, verifying the diagnosis, which enables the start of de-escalating ABT in patients with clinical signs of sepsis. Intensive care unit outcome versus haemodynamic status on arrival at a general intensive care unit Intensive care unit outcome versus haemodynamic status on arrival at a general intensive care unit T Reynolds, A Theodoraki, I Ketchley, A Tillyard, R Lawson, N Al-Subaie, M Cecconi, R Grounds, A Rhodes St George’s Hospital, London, UK Critical Care 2007, 11(Suppl 2):P43 (doi: 10.1186/cc5203) Introduction Goal-directed therapeutic protocols such as that described by Rivers and colleagues [1] have taken an important place in efforts to increase survival in septic patients. We looked at ICU outcomes for patients meeting the haemodynamic criteria of the Rivers trial on admission to our general ICU. Results Group A. Sepsis was diagnosed in 16/50 (32%) patients. PCT > 2 ng/ml was observed in 23/50 (46%) cases, including 15/16 (94%) patients with clinically diagnosed sepsis. In patients with PCT > 2 ng/ml the mortality rate was 7.7% if carbapenems (meropenem or imipenem/cilastatin) were administered (n = 13), compared with 20% with different ABT (n = 10) – although in patients with PCT < 2 ng/ml (n = 27), ABT with carbapenems (n = 12) resulted in paradoxically higher mortality compared with other ABT schemes (n = 15): 17% vs 6.6%. Group B. Sepsis was defined in 24/324 (7.4%) patients. PCT > 2 ng/ml was in 53/324 (16%) cases, including all patients with clinically diagnosed sepsis. Early ABT with meropenem, combined with vancomycin or linezolid, allowed one to decrease sepsis-related mortality in these patients to 29%, which used to be as high as 74% before the introduction of this algorithm (P = 0.0028). Methods We prospectively recorded haemodynamic parameters of 98 consecutive patients admitted to a mixed medical/surgical ICU and compared these with the ICU outcome. Patients who met systemic inflammatory response syndrome (SIRS) criteria [2] and had lactate ≥4 mmol/l or systolic blood pressure ≤90 mmHg met the Rivers criteria. Results We included 98 patients admitted to the ICU (60 males) of mean age 61 ± 17 years. Fourteen patients (14%) died in the ICU, and the median length of stay was 3 (IQR 3) days. Overall 16 of the 98 patients met the Rivers criteria, four of whom died (25%). The median length of ICU stay for the Rivers patients was 5 (1.25) days (see Table 1). Conclusions Sixteen out of 98 patients (16%) met Rivers criteria. Of medical and surgical emergency patients, this proportion rose to 16 of 55 patients (29%). P42 Methods The first standard was implemented for the treatment of the Waterhouse–Friderichsen syndrome. At first, we started with the educational program. The program included different central symposia about septic shock in children. The second step was the standardisation of the diagnosis and the therapy, including the administration of human protein C concentrate (PC), and the clinical pathways. We implemented a round-the-clock emergency system with the possibility for transportation of critically ill patients, permanent consultation of the tertiary medical center and onsite treatment through the tertiary center staff if the patient could not be transferred. All patients were announced to the tertiary medical Conclusion ANH with hydroxyethyl starch influences oxidative burst activity under experimental conditions. S16 Available online http://ccforum.com/supplements/11/S2 P44 Optimization of antibacterial treatment in pediatric intensive care units using procalcitonin Methods Three hundred and seventy-four patients on artificial lung ventilation from two pediatric ICUs of two Russian hospitals were enrolled. Blood samples for PCT testing (PCT LIA; BRAHMS AG, Germany) were taken under suspicion of sepsis or exacerbation of bacterial infection. In the first stage (January–December 2005), 50 neonates (age 6 (4–12) days) with various perinatal pathologies were studied (Group A), and routine ABT was prescribed, with blood samples taken and stored for further PCT assessment. In the second stage (January–November 2006), 324 infants (age 6 (1.5–9.4) months) after cardiac surgery were enrolled (Group B), and ABT was adjusted based on PCT-testing results. PCT > 2 ng/ml indicative of systemic bacterial inflammation in addition to clinical signs of sepsis was an indication for ABT with carbapenems. Data are shown as the median and interquartile range. P45 approximately equivalent to an endotoxin concentration of 25–50 pg/ml, and a level of 0.6 is approximately equivalent to a LPS concentration of 100–200 pg/ml. Data were analysed according to EA ranges: low (EA < 0.4), intermediate (0.4 ≤EA < 0.6), and high (EA ≥0.6). Differences between ranges of EA were assessed by analysis of variance (Sigma Stat, SPSS), accepting P < 0.05 as significant. Data are expressed as the mean ± SD. M Assuncao1, F Machado1, N Akamine2, G Cardoso1, P Mello3, J Telles4, A Nunes5, M Oliveira6, A Rea-Neto7, R Clleva8, F Dias9 1Universidade Federal de Sao Paulo, Brazil; 2Latin American Sepsis Institute, Sao Paulo, Brazil; 3Universidade Estadual do Piaui, Teresina, Brazil; 4Hospital Portugues, Salvador, Brazil; 5Hospital Sao Camilo, Sao Paulo, Brazil; 6Hospital Santa Luzia, Brasilia, Brazil; 7Universidade Federal do Parana, Curitiba, Brazil; 8Faculdade de Medicina da USP, Sao Paulo, Brazil; 9Hospital Sao Lucas – PUC-RS, Porto Alegre, Brazil Critical Care 2007, 11(Suppl 2):P45 (doi: 10.1186/cc5205) M Assuncao1, F Machado1, N Akamine2, G Cardoso1, P Mello3, J Telles4, A Nunes5, M Oliveira6, A Rea-Neto7, R Clleva8, F Dias9 1Universidade Federal de Sao Paulo, Brazil; 2Latin American Sepsis Institute, Sao Paulo, Brazil; 3Universidade Estadual do Piaui, Teresina, Brazil; 4Hospital Portugues, Salvador, Brazil; 5Hospital Sao Camilo, Sao Paulo, Brazil; 6Hospital Santa Luzia, Brasilia, Brazil; 7Universidade Federal do Parana, Curitiba, Brazil; 8Faculdade de Medicina da USP, Sao Paulo, Brazil; 9Hospital Sao Lucas – PUC-RS, Porto Alegre, Brazil Critical Care 2007, 11(Suppl 2):P45 (doi: 10.1186/cc5205) Results In our case mix, patients were 68 (65%) in the low group, 17 (17%) in the intermediate group and 19 (18%) in the high group. Age (61 ± 17 years) was not significantly different in the three groups (P = 0.493). Functional and severity scores were not significantly different between groups. Average values were as follows: WBC 11,093 ± 4605 n/mm3 (P = 0.385), HR 76 ± 16 bpm (P = 0.898), MAP 88.8 ± 13.6 mmHg (P = 0.576), lactate 1.18 ± 0.77 mmol/l (P = 0.370), PaO2/FiO2 383 ± 109 mmHg (P = 0.474), APACHE II score 8.3 ± 3.7 (P = 0.542) and SOFA score 1.5 ± 1.4 (P = 0.245). Interestingly, those patients with higher levels of EA were characterized by longer length of stay in the ICU. P45 The ICU length of stay was 1.9 ± 3.1 days in the low group, 8.7 ± 6.7 days in the intermediate group and 4.7 ± 7.7 days in the high group (P = 0.038). Introduction The aim of this study was evaluation of physicians’ knowledge about SIRS, sepsis, severe sepsis and septic shock. Methods A multicenter study in 21 ICUs in seven university, five public and seven private hospitals. A questionnaire with five clinical cases was first validated by five critical care boarded intensivists (INT) with 100% agreement. All interviewed physicians (Phys) received each question separately, in a predefined sequence, and no answer could be reviewed. After answering, the questionnaire was put in a sealed envelope with no identification. Statistical analysis was performed: chi-square, Kruskall–Wallis and linear correlation tests. P < 0.05 was considered statistically significant. Results A total of 917 Phys (mean age 32.7 ± 7.21 years, 61.9% males, 38.1% females) were enrolled with 20.0% (n = 55) INT and 80.0% (n = 220) of nonintensivists (non-INT). Phys correctly recognized SIRS, infection, and septic shock in 80.4%, 92.4% and 85.1% of the cases, respectively. The lowest rate of recognition was observed in sepsis and severe sepsis cases (26.5% and 55.6%). Considering all questions, the overall percentage of correct answers was 68.1 ± 21.1%. INT performed better than non-INT (84.7 ± 17.2% and 64.0 ± 20.0%, P < 0.00001). Phys working at public and university hospitals performed better (70.2 ± 18.7% and 71.2 ± 19.5%) than those in private hospitals (59.7 ± 23.4%, P = 0.001). Introduction The aim of this study was evaluation of physicians’ knowledge about SIRS, sepsis, severe sepsis and septic shock. Methods A multicenter study in 21 ICUs in seven university, five public and seven private hospitals. A questionnaire with five clinical cases was first validated by five critical care boarded intensivists (INT) with 100% agreement. All interviewed physicians (Phys) received each question separately, in a predefined sequence, and no answer could be reviewed. After answering, the questionnaire was put in a sealed envelope with no identification. Statistical analysis was performed: chi-square, Kruskall–Wallis and linear correlation tests P < 0 05 was considered statistically significant Conclusions A rather high number of patients admitted to the ICU following elective surgery are characterized by intermediate-high levels of endotoxemia, as assessed by the EA assay, despite their relative low level of complexity on admission. Reference 1. Romaschin AD, et al.: J Immunol Methods 1998, 212:169- 185. 1. Romaschin AD, et al.: J Immunol Methods 1998, 212:169- 185. Intensive care unit outcome versus haemodynamic status on arrival at a general intensive care unit Conclusion Early verification of sepsis using PCT combined with carbapenems-based ABT enables decreasing sepsis-related mortality in critically ill infants and newborns staying in the ICU. 1. Rivers E, et al.: N Engl J Med 2001, 345:1368-1377. 2. Levy M, et al.: Crit Care Med 2003, 31:1250-1256. 1. Rivers E, et al.: N Engl J Med 2001, 345:1368-1377. 2 L M l C i C M d 2003 31 1250 1256 S Table 1 (abstract P43) Patients Patients reaching Rivers criteria Mortality Median length of stay Mortality Median length of stay n (n (%)) (days) n (n (%)) (days) Total 98 14 (14%) 3 (IQR 3) 16 4 (25%) 5 (IQR 1.25) Medical 33 9 (27%) 5 (IQR 2) 11 3 (27%) 5 (IQR 1.5) Elective surgical 43 1 (2%) 2 (IQR 1) 0 Emergency surgical 22 4 (18%) 3 (IQR 4.5) 5 1 (20%) 5 (IQR 1) Table 1 (abstract P43) Table 1 (abstract P43) S17 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin sTREM-1 is not suitable to discriminate survivors and nonsurvivors in surgical patients with severe sepsis or septic shock sTREM-1 is not suitable to discriminate survivors and nonsurvivors in surgical patients with severe sepsis or septic shock C Bopp1, S Hofer1, P Kienle1, S Meyer1, E Martin1, A Bouchon2, M Buechler1, M Weigand1 1University of Heidelberg, Germany; 2Bayer CropScience, Monheim, Germany Critical Care 2007, 11(Suppl 2):P47 (doi: 10.1186/cc5207) Conclusion The recognition of sepsis and its severity are not satisfactory, mostly among non-INT and those working at private hospitals. Possibly, reviewing sepsis-related and organ dysfunction concepts are necessary for early identification of septic patients. Objectives To evaluate in septic patients the plasma levels of sTREM-1, a soluble form of TREM-1, which seems to play an important role in inflammatory diseases, and to determine whether plasma sTREM-1 could be used as a diagnostic and prognostic marker in sepsis in the surgical ICU. P45 High levels of EA were associated with a longer length of stay. correlation tests. P < 0.05 was considered statistically significant. Results A total of 917 Phys (mean age 32.7 ± 7.21 years, 61.9% males, 38.1% females) were enrolled with 20.0% (n = 55) INT and 80.0% (n = 220) of nonintensivists (non-INT). Phys correctly recognized SIRS, infection, and septic shock in 80.4%, 92.4% and 85.1% of the cases, respectively. The lowest rate of recognition was observed in sepsis and severe sepsis cases (26.5% and 55.6%). Considering all questions, the overall percentage of correct answers was 68.1 ± 21.1%. INT performed better than non-INT (84.7 ± 17.2% and 64.0 ± 20.0%, P < 0.00001). Phys working at public and university hospitals performed better (70.2 ± 18.7% and 71.2 ± 19.5%) than those in private hospitals (59.7 ± 23.4%, P = 0.001). Reference Prevalence of endotoxemia in a population of patients admitted to an intensive care unit after elective surgery Design An observational clinical study. Design An observational clinical study. F Valenza, L Fagnani, S Coppola, S Froio, C Tedesco, C Marenghi, C Galbusera, P Caironi, L Gattinoni Fondazione IRCCS Ospedale Maggiore Policlinico Mangiagalli Regina Elena, Milano, Italy Critical Care 2007, 11(Suppl 2):P46 (doi: 10.1186/cc5206) Valenza, L Fagnani, S Coppola, S Froio, C Tedesco, Setting The surgical ICU of the University Hospital of Heidelberg, Germany. Setting The surgical ICU of the University Hospital of Heidelberg, Germany. Patients Patients admitted to the ICU over a 6-month period with clinical evidence of severe sepsis or septic shock. Patients Patients admitted to the ICU over a 6-month period with clinical evidence of severe sepsis or septic shock. Can plasma-free DNA concentration be a diagnostic tool in critically ill septic patients? Can plasma-free DNA concentration be a diagnostic tool in critically ill septic patients? Introduction Inadequate tissue perfusion and an uncontrolled systemic inflammatory response are associated with poor outcome in critically ill surgical patients. An increased concentration of un- measured anions, reflecting hypoperfusion, and the magnitude of the early inflammatory response both correlate strongly with mortality. Our aim was to assess the relationship between these factors, and their ability in combination to predict outcome. Introduction Inadequate tissue perfusion and an uncontrolled systemic inflammatory response are associated with poor outcome in critically ill surgical patients. An increased concentration of un- measured anions, reflecting hypoperfusion, and the magnitude of the early inflammatory response both correlate strongly with mortality. Our aim was to assess the relationship between these factors, and their ability in combination to predict outcome. Methods In a prospective study we evaluated 108 consecutive patients admitted to a surgical high dependency unit. Regional Ethics Committee approval was obtained. Serum electrolytes, albumin, phosphate, lactate and C-reactive protein (CRP) were measured on admission and on day 1. We derived the calculated ion gap (CIG) using a simplified modification of the Stewart–Figge equations. B Orbey1, H Cuhruk1, M Tulunay1, M Oral2, N Unal1, H Ozdag3 1Ankara University Medical Faculty, Anesthesiology and ICM, Ankara, Turkey; 2AÜTF, Anesthesiology and ICU, Ankara, Turkey; 3Ankara University, Biotechnology Institute, Ankara, Turkey Critical Care 2007, 11(Suppl 2):P48 (doi: 10.1186/cc5208) Methods In a prospective study we evaluated 108 consecutive patients admitted to a surgical high dependency unit. Regional Ethics Committee approval was obtained. Serum electrolytes, albumin, phosphate, lactate and C-reactive protein (CRP) were measured on admission and on day 1. We derived the calculated ion gap (CIG) using a simplified modification of the Stewart–Figge equations. Recent evidence suggests that the plasma-free DNA concentration has potential use as a prognostic marker in many clinical situations including sepsis, trauma, and acute stroke [1]. However, its predictive value is arguable. We hypothesized that plasma DNA is increased in septic patients admitted to the ICU compared with nonseptic ICU patients, and it is correlated with disease severity and clinical outcome. Results Based on previous work, thresholds of 10 mmol/l for CIG and 100 mg/l for CRP were used to categorise patients. Of the patients with a CRP < 100 mg/l, 15.4% had an elevated CIG. Of the patients with a CRP > 100 mg/l, 36.7% had an elevated CIG (P = 0.016, chi-square test). Can plasma-free DNA concentration be a diagnostic tool in critically ill septic patients? Patients (n = 63) with a CIG < 10 mmol/l and CRP < 100 mg/l had a 1.5% mortality, whereas those (n = 11) with a CIG > 10 mmol/l and CRP > 100 mg/l had a 54.5% mortality (P < 0.0001, chi-square test) (Table 1). Forty-two consecutive patients (11 septic, 31 nonseptic) admitted to a mixed ICU and mechanically ventilated were recruited. Plasma- free DNA concentration was measured by real-time PCR assay for the β-globin gene, and the APACHE II score, SOFA score, serum C-reactive protein (CRP) concentrations, procalcitonin (PCT) concentrations, serum lipid concentrations, and clinical outcome (ICU/hospital days and mortality) were assessed on admission to the ICU. Assessments and samplings were repeated as the diagnosis of the patients changed (sepsis, severe sepsis and septic shock). Finally, 86 plasma samples were collected. Descrip- tive statistics, Mann–Whitney U, Kruskall–Wallis and Spearman’s tests, and receiver operating characteristic analysis were used when appropriate. Table 1 (abstract P49) CRP < 100 mg/l, CRP > 100 mg/l, CIG < 10 mmol/l CIG > 10 mmol/l Inhospital mortality 1.5% (n = 63) 54.5% (n = 11) Demographic data were similar. ICU and hospital mortalities were 26.2% and 33.3%, respectively. The mean DNA concentrations on admission were significantly higher in ICU patients compared with healthy subjects (n = 11) (13,405 GE/ml versus 390 GE/ml, P < 0.05) and septic patients compared with nonseptic patients (33,170 GE/ml versus 1,171 GE/ml, P < 0.001). Furthermore, during the overall ICU stay, increased DNA concentration asso- ciated with the increase of severity of illness was noted; however, this increase was statistically significant only between septic and septic shock samples (26,624 GE/ml versus 42,861 GE/ml, P < 0.05). The area under the curve obtained for the plasma-free DNA concentration in distinguishing between septic and nonseptic patients on admission was 0.9 (sensitivity 84%, specificity, 95%; cutoff 4,083 GE/ml). Also, the plasma-free DNA concentration was found to be higher in patients who died in the ICU compared with patients who survived, although not statistically significant. The DNA concentration demonstrated a significant correlation with CRP (P = 0.037, r = 0.365), PCT (P = 0.007, r = 0.457) and high- density lipoprotein (P = 0.015, r = –0.415) concentrations. Conclusion Inflammation is a potent cause of oxidative stress, which in turn results in endothelial damage and increased concentrations of unmeasured anions. Interventions None. Measurements and results Sixty-six intensive care patients were enrolled in the study within the first 24 hours after the onset of severe sepsis or septic shock. Twenty-one healthy individuals served as controls. At day 0, day 1 and day 3 after diagnosis of severe sepsis or septic shock, plasma sTREM-1 was measured by ELISA. Plasma sTREM-1 concentrations of healthy controls did not differ from patients with severe sepsis or septic shock at day 0 (42.8 ± 44.9 pg/ml vs 40.8 ± 45.5 pg/ml, not significant), day 1 (42.8 ± 44.9 pg/ml vs 48.6 ± 57.2 pg/ml, not significant) nor at day 3 (42.8 ± 44.9 pg/ml vs 51.9 ± 52.8 pg/ml, not significant). Survivors were defined as patients surviving to at least day 28. There were no differences of plasma sTREM-1 between survivors and nonsurvivors at day 0, day 1 and day 3 (34.8 ± 44 52.4 pg/ml Introduction The aim of this study was to investigate the prevalence of endotoxemia early after elective surgical procedures in patients admitted to an ICU of a university hospital. Introduction The aim of this study was to investigate the prevalence of endotoxemia early after elective surgical procedures in patients admitted to an ICU of a university hospital. Methods One hundred and four nonselect patients were recruited. Patients were excluded if they were admitted during the weekend or from another ICU and if they were on chronic dialysis. Within 4 hours of admission functional data were collected and severity scores (APACHE, SOFA) calculated. Arterial blood samples were also taken and processed according to Spectral Diagnostics’ endotoxin activity (EA) assay [1]. The method allows one to express EA as a function of each patient’s neutrophil chemi- luminescence activity (on a scale from 0 to 1). An EA level of 0.4 is S18 Available online http://ccforum.com/supplements/11/S2 1. Rhodes A, et al.: Plasma DNA concentration as a predictor of mortality and sepsis in critically ill patients. Crit Care 2006, 10:142. Can plasma-free DNA concentration be a diagnostic tool in critically ill septic patients? The combination of CRP and the CIG, as markers of inflammation and inadequate tissue perfusion, respectively, is a powerful predictor of mortality in the critically ill surgical patient. P49 vs 49.5 ± 35.9 pg/ml, 42.6 ± 61.1 pg/ml vs 59.6 ± 47.1 pg/ml, and 47.9 ± 60.2 pg/ml vs 58.2 ± 37.1 pg/ml, not significant). Conclusion In this study including surgical patients with severe sepsis or septic shock, plasma sTREM-1 is not elevated compared with healthy controls. Furthermore, the measurement of plasma sTREM-1 did not allow one to differ between survivors and nonsurvivors. The suggested role of sTREM-1 as a diagnostic and prognostic marker in sepsis was not confirmed in this study. vs 49.5 ± 35.9 pg/ml, 42.6 ± 61.1 pg/ml vs 59.6 ± 47.1 pg/ml, and 47.9 ± 60.2 pg/ml vs 58.2 ± 37.1 pg/ml, not significant). Conclusion In this study including surgical patients with severe sepsis or septic shock, plasma sTREM-1 is not elevated compared with healthy controls. Furthermore, the measurement of plasma sTREM-1 did not allow one to differ between survivors and nonsurvivors. The suggested role of sTREM-1 as a diagnostic and prognostic marker in sepsis was not confirmed in this study. Greater than the sum of its parts: C-reactive protein and the calculated ion gap together are superior in predicting mortality in critically ill surgical patients F Leitch1, E Dickson1, A McBain1, S Robertson2, D O’Reilly1, C Imrie1 1Glasgow Royal Infirmary, Glasgow, UK; 2Johannesburg Hospital, Johannesburg, South Africa Critical Care 2007, 11(Suppl 2):P49 (doi: 10.1186/cc5209) C-reactive protein predicts mortality on admission to a surgical high-dependency unit Introduction C-reactive protein (CRP) is a non-specific marker that may be used to assess the magnitude of the inflammatory response in critically ill surgical patients. Our aim was to determine the temporal relationship between CRP measurement and mortality. Methods In a prospective study conducted in a surgical high- dependency unit (HDU), 132 consecutive patients were evaluated. Regional Ethics Committee approval was obtained. Serum CRP In conclusion, plasma DNA may be a potentially valuable tool to confirm the diagnosis of sepsis on admission to the ICU and to monitor disease severity. The biphasic aPTT waveform to diagnose sepsis in patients with systemic inflammatory response syndrome The biphasic aPTT waveform to diagnose sepsis in patients with systemic inflammatory response syndrome D Hagg, S Malkoski, C Phillips, D Nichols, D Jacoby Oregon Health & Science University, Portland, OR, USA Critical Care 2007, 11(Suppl 2):P51 (doi: 10.1186/cc5211) Results We included 65 patients. The total mortality rate was 16.9% (11 patients). Introduction We tested the ability of the biphasic aPTT waveform to diagnosis sepsis in patients presenting to the Emergency Department (ED) with the systemic inflammatory response syndrome (SIRS). The biphasic aPTT waveform (BPW), which results from rapid complexing of VLDL and C-reactive protein during aPTT testing, has demonstrated promise as an early diagnostic test for sepsis. Table 1 (abstract P52) n = 65 FPC Lactate P Mortality (%) Group I 30.9 ± 9 15.7 ± 5.8 <0.05 78 Group II 58.1 ± 13 1.8 ± 0.35 22 Group III 100.8 ± 12.8 1.3 ± 0.9 <0.05 0 Methods A prospective, observational study was designed in which all patients presenting to the ED of an urban university hospital were screened for SIRS. Patients with SIRS unrelated to trauma or myocardial infarction were eligible. Plasma for BPW testing was obtained at the time of enrollment and daily for 7 days in admitted subjects. The primary outcome was a diagnosis of sepsis related to the presence of a BPW at enrollment. Secondary measures were mortality related to the BPW, correlation of any positive BPW with sepsis, and of the BPW with statin therapy. Two criteria for a positive test, light transmittance at 18 seconds (TL18) and the initial slope of the waveform (slope) are used. Two independent experts made the final diagnosis. Conclusions We found a direct and a progressive relation with statistical significance between the higher mortality rate and the lower protein C values. The results could mean that the level of protein C can be used as an evolution marker in septic patients. Functional protein C levels in septic patients E Lafuente, I Pratima, M Fernandes, J Gomes da Silva, F Moura, F Santos, I Guimaraes, R Lopes, P Santos Padre Americo, Penafiel, Portugal Critical Care 2007, 11(Suppl 2):P52 (doi: 10.1186/cc5212) Table 1 (abstract P50) CRP <100 mg/l CRP >100 mg/l P value Inhospital mortality 2.2% (n = 93) 25.6% (n = 39) <0.0001 (chi-square) Objective To know whether functional protein C (FPC) levels in critical septic patients could be intended as an evolution marker correlated with prognosis and mortality. Materials and methods A prospective study with determination of FPC levels in all septic patients admitted to the ICU. We used the IL test™ PC kit (Instrumentation Laboratory; synthetic chromogenic substrate). We considered an abnormal low FPC when levels were below 40%, normal FPC when levels were above 80% and low FPC when levels where between 40% and 80%. Data included patient age, diagnosis, SAPS II, SOFA score, OSF and mortality. The analytical data included serum lactate and FPC. Patients were divided into three groups: group I (FPC below 40%), group II (FPC 40–80%) and group III (FPC above 80%). The statistical study was performed with the Analyse-it® program. The severity was defined by the usual criteria of SAPS II score and lactate levels and then compared with the different FPC groups. Mortality was considered. Conclusion CRP on admission to the surgical HDU is a powerful predictor of mortality (P < 0.0001), but this correlation does not persist after the initial measurement. Our data suggest that early CRP measurement should be undertaken in all critically ill surgical patients in order to quantify the ultimate magnitude of the inflammatory response and the associated mortality. Reference 1. Rhodes A, et al.: Plasma DNA concentration as a predictor of mortality and sepsis in critically ill patients. Crit Care 2006, 10:142. S19 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin was measured on admission, day 1 and day 2 and was evaluated with respect to inhospital mortality. Conclusion The BPW has no utility in the ED to predict the development of sepsis in at-risk patients. The development of a BPW at any time during the hospital stay correlates with an increased risk of sepsis and mortality. Baseline statin therapy may reduce the chance of developing a BPW. Results CRP on admission to HDU discriminated survivors from nonsurvivors (P < 0.0001, analysis of variance). A CRP greater than 100 mg/l correlated very strongly with mortality. The mortality in patients with a CRP less than 100 mg/l (n = 93) was 2.2%. The mortality in patients with a CRP greater than 100 mg/l (n = 39) was 25.6% (P < 0.0001, chi-square test), (Table 1). However, there were no significant differences in CRP with respect to mortality on day 1 or day 2 (P = 0.136 and 0.236, respectively). Severe protein C deficiency association with organ dysfunction and mortality in patients with severe sepsis Results We screened 5,400 consecutive admissions to the ED, identified 207 eligible subjects and enrolled 105 participants. The BPW was present at enrollment in 12 subjects by TL18 and in 28 subjects by slope. Forty-six out of 105 subjects eventually developed a BPW, 54 were diagnosed with sepsis. The sensitivity and specificity for sepsis were 17% (95% CI, 7–27.6) and 93.8% (95% CI, 87–100) by TL18 and 26.9% (95% CI, 14.9–38.9) and 71.4% (95% CI, 58.7–84.1) by slope. The positive predictive value of the test was 75 by TL18 and 50 by slope criteria. The AUC for ROC analysis of the BPW for diagnosis of sepsis is 0.469 by TL18 and 0.560 by slope. The odds ratio for developing sepsis related to any positive BPW was 2.977. The odds ratio for development of a BPW in patients on a statin at the time of presentation was 0.597. Five subjects died by 28 days, 4/5 having a BPW. Introduction We sought to determine whether severe protein C (PC) deficiency was associated with organ dysfunction (OD) and mortality in adult patients with severe sepsis. Introduction We sought to determine whether severe protein C (PC) deficiency was associated with organ dysfunction (OD) and mortality in adult patients with severe sepsis. Introduction We sought to determine whether severe protein C (PC) deficiency was associated with organ dysfunction (OD) and mortality in adult patients with severe sepsis. Methods Retrospective examination of Lilly trials in adult patients with severe sepsis in which PC measurements were obtained at baseline. Severe PC deficiency was defined as ≤40% of normal. The Student t test was used to compare mean APACHE II and OD differences, while the chi-squared or Fisher’s exact test was used for mortality. Introduction We sought to determine whether severe protein C (PC) deficiency was associated with organ dysfunction (OD) and mortality in adult patients with severe sepsis. Methods Retrospective examination of Lilly trials in adult patients with severe sepsis in which PC measurements were obtained at baseline. Severe PC deficiency was defined as ≤40% of normal. The Student t test was used to compare mean APACHE II and OD differences, while the chi-squared or Fisher’s exact test was used for mortality. Methods Retrospective examination of Lilly trials in adult patients with severe sepsis in which PC measurements were obtained at baseline. Severe PC deficiency was defined as ≤40% of normal. P51 The biphasic aPTT waveform to diagnose sepsis in patients with systemic inflammatory response syndrome The biphasic aPTT waveform to diagnose sepsis in patients with systemic inflammatory response syndrome D Hagg, S Malkoski, C Phillips, D Nichols, D Jacoby Oregon Health & Science University, Portland, OR, USA Critical Care 2007, 11(Suppl 2):P51 (doi: 10.1186/cc5211) Human protein C concentrate in the treatment of hemolytic uremic syndrome Human protein C concentrate in the treatment of hemolytic uremic syndrome M Sasse, L Pape, H Koeditz, A Wessel, K Seidemann, J Thomas, B Brent Medical University Children’s Hospital, Hannover, Germany Critical Care 2007, 11(Suppl 2):P54 (doi: 10.1186/cc5214) In severe sepsis, microcirculatory dysfunction caused by inflam- mation, endothelial activation and procoagulant response leads to mithocondrial dysfunction (termed microcirculatory and mito- chondrial distress syndrome). If undetected, this condition can lead to parenchymal cellular distress and so to organ failure. As regional and microcirculatory distress are independent of systemic hemo- dynamic-derived and oxygen-derived variables, we recorded the course of microvascular parameters with a Microscan Video Micro- scope (Microvision, The Netherlands) in four patients with severe sepsis. We studied the sublingual region because of its embryo- logic correlation to splanchnic circulation, its thin mucosa. The instrument used a new improved imaging modality for observation of the microcirculation called sidestream dark-field imaging. We consider here four patients with severe sepsis related to esophagectomy, severe polytrauma with splanchnic organ damage and mediastinitis treated with drotrecogin alpha (activated) (DA) at 24 µg/kg/hour for 96 hours. The patients were admitted to the ICU, ventilated mechanically, monitored hemodynamically via a PICCO system and supported with dobutamine. Videomicroscopy was made before administration of DA and was repeated every 24 hours during the treatment with DA and at 24 hours after its suspension. We recorded values of blood pressure, cardiac func- tion, lactate levels, acid–base balance, temperature and dobuta- mine dosage. Introduction Human protein C (PC) concentrate may anticipate thrombotic microangiopathy and facilitate fibrinolysis in the severe hemolytic uremic syndrome (HUS). We report the effects of PC in six HUS patients. HUS is characterized by a simultaneous occur- rence of hemolytic anemia, thrombocytopenia and acute renal failure. Postdiarrheal HUS is often based on an infection with EHEC producing Shiga toxins. Our current pathogenetic under- standing is that Shiga toxins cause endothelial injury, leading to thrombotic microangiopathy. There is still a 5% rate of mortality particularly caused by cerebral involvement. Methods We treated six children with a severe cerebral manifes- tation, five of them suffered from a multiple organ dysfunction syndrome (MODS), of HUS with PC over 7–10 days. All patients suffered peritoneal dialysis, one patient a plasmapheresis. In addition to the treatment of the MODS, all of them received 100–200 U/day PC. Results All of the patients showed signs of disseminated intravascular coagulation. P55 A Donati, M Romanelli, L Romagnoli, M Ruzzi, V Beato, V Gabbanelli, S Nataloni, T Principi, P Pelaia AOU Umberto I Ancona, Rianimazione Clinica, Ancona, Italy Critical Care 2007, 11(Suppl 2):P55 (doi: 10.1186/cc5215) Severe protein C deficiency association with organ dysfunction and mortality in patients with severe sepsis The Student t test was used to compare mean APACHE II and OD differences, while the chi-squared or Fisher’s exact test was used for mortality. S20 Available online http://ccforum.com/supplements/11/S2 Table 1 (abstract P53) Study EVAA PROWESS ENHANCE ADDRESS Protein C ≤40% >40% ≤40% >40% ≤40% >40% ≤40% >40% n 65 60 615 959 795 1127 593 1154 Mean APACHE II 17.4 17.1 P = 0.79 25.9 24.1 P < 0.001 23.2 20.9 P < 0.001 18.5 18.1 P = 0.14 score Mean OD 1.5 1.4 P = 0.42 2.8 2.2 P < 0.001 3.1 2.4 P < 0.001 1.6 1.4 P < 0.001 Placebo mortality 50.0% 20.0% P = 0.07 41.8% 25.3% P < 0.001 19.7% 12.0% P = 0.002 Table 1 (abstract P53) patients yield hope that PC treatment may be an effective therapy regimen in the treatment of severe HUS. Results Severe PC deficiency was associated with a statistically significant increase in the mean APACHE II score in two of four trials, a significant increase in the mean OD in three of four trials, and a significant increase in mortality in two of three trials (Table 1). Conclusion Severe PC deficiency at baseline appears to be associated with a greater degree of organ dysfunction, and increased mortality in adult patients with severe sepsis. P56 Results A total number of 61 patients, aged 18–65 years, were included in the analysis. The pathogens and infection location were different. Patients were diagnosed according to recommendations of the Polish Sepsis Group and treatment with APC was introduced. The increase in number was: in 2004 vs 2003, 200%; in 2005 vs 2004, 111%; in 2006 up to 10 December vs 2005, 57.8%. The surviving ratio increased every year but in 2006 it decreased compared with 2005. Multicentre audit of the use of drotrecogin alfa (activated) in UK critical care units Multicentre audit of the use of drotrecogin alfa (activated) in UK critical care units Human protein C concentrate in the treatment of hemolytic uremic syndrome We found typical hypodense lesions in basal ganglia and edema of the brain in CT. During the therapy with PC, MODS was remarkable improved and abnormal D-dimer and PAI-1 levels could be normalised. All of the patients recovered a nearly normal kidney function. Two patients persisted in a severe reduced neurological status. The others showed only slight or no neurological disabilities on discharge. No adverse effects were observed with the PC concentrate administration. At admission the sublingual microcirculation showed a low capillary density, vessel heterogeneity with a qualitative low flow and flow–no flow. After the first 24 hours from the beginning of DA infusion, sublingual flow showed an increase of vessel density, particularly of the number of small vessels, and the number of continuously perfused vessels increased during and post therapy with DA. We analyzed the microvascular flow with a simple semi- quantitative method dividing the images into four equal quadrants and quantificating flow (hyperdynamic, continuous, sluggish, flow–no flow, no flow) for each cohort of vessel diameter (small, medium, large). We analyzed the mean value of results of three images for each patient pre and post DA therapy. Data are presented as the median. Before starting therapy with DA, the microvascular flow index (MFI) was 2.06 for small vessels, 2.09 for medium vessels, and 2.37 for large vessels. After DA infusion, the MFI was 3, 3, and 3, respectively, for small, medium and large Conclusions There is no generally accepted therapy regimen to treat HUS in case of neurological involvement. Mortality in HUS accompanied with cerebral microangiopathy is high and difficult to alter. This is the first trial of human PC concentrate administration to anticipate thrombotic microangiopathy in HUS. All of our patients showed rapid clinical improvement under PC administration. Four of six patients were discharged in a healthy condition despite their severe disease. The containment of the severe neurological involvement and the lack of side effects in the treatment with human PC concentrate administration in our S21 Table 1 (abstract P57) Table 1 (abstract P57) 2003 2004 2005 2006 (10 Dec) Number of treated 3 9 19 30 patients Surviving ratio 33% (1/3) 43.5% (4/9) 62.7% 47% Methods A data collection form was developed and tested to mirror the information collected in PROWESS. This form was completed for every admission that received DrotAA and a senior clinician confirmed completeness. Data were entered centrally and validated. Analysis Admissions receiving DrotAA and with severe sepsis and two or more organ dysfunctions in the first 24 hours following admission to the unit were matched to controls on: source of admission; organ dysfunctions; ICNARC physiology score; and age. Four pools of control patients were used for matching: (a) historic admissions (January 2000–August 2002) from the same unit; (b) contemporaneous admissions from the same unit; (c) contemporaneous admissions from units that never used DrotAA; and (d) contemporaneous admissions from units prior to their first use of DrotAA. Analyses were undertaken using conditional, fixed- effects, Poisson regression. Discussion During 4 years of treatment of severe sepsis in the ICU with APC, important changes were observed: faster recognition and diagnosis, transfer to the reference hospital, and introduction of adequate therapy. The decrease in the surviving ratio in 2006 is probably due to a more serious state of the admitted patients – more initial infection located in the abdomen after surgery. Conclusion The education program is essential in increasing the number of fast recognitions, which influences the surviving ratio. P58 Results One hundred and twelve units participated in the audit; 1,079 admissions (one in 16) with severe sepsis and two or more organ dysfunctions in the first 24 hours following admission to the unit received DrotAA. For the four control pools, matching was successful for: (a) 657 (61%); (b) 820 (76%); (c) 702 (65%); and (d) 965 (89%). Matched cases were older, more acutely ill and had higher hospital mortality than unmatched cases. The relative risks (95% confidence interval) associated with DrotAA were: (a) 0.84 (0.77–0.92); (b) 0.85 (0.78–0.93); (c) 0.75 (0.68–0.83); and (d) 0.80 (0.73–0.86). A priori subgroup analyses indicated greater effect for patients with three or more organ dysfunctions. A large, single-centre UK registry of drotrecogin alfa-activated use Surviving ratio of severe sepsis treated with activated protein C in one university intensive care unit during 2003–2006 Surviving ratio of severe sepsis treated with activated protein C in one university intensive care unit during 2003–2006 A Tokarz, T Gaszynski, W Gaszynski Medical University of Lodz, Poland Critical Care 2007, 11(Suppl 2):P57 (doi: 10.1186/cc5217) Introduction Treatment of severe sepsis with infusion of activated protein C (APC) (Xigris) in the ICU of Barlicki University Hospital was initiated in 2003. From 2003 the number of treated patients increased significantly. This is due to better recognition. The introduced program consists of education of working staff in all hospitals in the region. Barlicki Hospital is a reference hospital for treatment of sepsis, and patients with diagnosis of sepsis are transferred to this ICU. University ICU doctors are teaching workshops how to recognize and treat sepsis. Methods The surviving ratio in patients treated with APC was estimated retrospectively. Analysis included the years from 2003 to 10 December 2006. Multicentre audit of the use of drotrecogin alfa (activated) in UK critical care units K Rowan, C Welch, E North, D Harrison Intensive Care National Audit & Research Centre, London, UK Critical Care 2007, 11(Suppl 2):P56 (doi: 10.1186/cc5216) Background Following positive results from PROWESS, drotrecogin alfa (activated) (DrotAA) was approved for use in Europe in August 2002. At this time, ICNARC commenced an audit to monitor the diffusion of the drug into routine UK practice and to undertake a nonrandomised evaluation of its effectiveness. P57 vessels. Differences between groups were assessed using the Mann–Whitney U test. We showed a statistically significant differ- ence with P < 0.0001 between MFI before and post DA therapy. We demonstrated a quantitative and qualitative improvement of sublingual microcirculation with an increase of capillary density distribution (area–width) and average velocity versus vessel width. The course of microvascular blood flow may play an important role in sepsis and septic shock because of its relation to the development of multiple organ failure and death. Several studies have demonstrated that changes in microvascular perfusion are an independent predictor of outcome. The improvement of the micro- circulation and vascular tone in septic shock by DA is probably related to its anticoagulant/antithrombotic and antiinflammatory action, to the decrease of TNFα production and inhibition of iNOS induction, and to improvement of endothelial barrier function and inhibition of chemotaxis, but further investigations are required to elucidate the exact mechanisms. These observations could suggest that DA could have a particular interest in the early management of severe sepsis. vessels. Differences between groups were assessed using the Mann–Whitney U test. We showed a statistically significant differ- ence with P < 0.0001 between MFI before and post DA therapy. We demonstrated a quantitative and qualitative improvement of sublingual microcirculation with an increase of capillary density distribution (area–width) and average velocity versus vessel width. The course of microvascular blood flow may play an important role in sepsis and septic shock because of its relation to the development of multiple organ failure and death. Several studies have demonstrated that changes in microvascular perfusion are an independent predictor of outcome. The improvement of the micro- circulation and vascular tone in septic shock by DA is probably related to its anticoagulant/antithrombotic and antiinflammatory action, to the decrease of TNFα production and inhibition of iNOS induction, and to improvement of endothelial barrier function and inhibition of chemotaxis, but further investigations are required to elucidate the exact mechanisms. These observations could suggest that DA could have a particular interest in the early management of severe sepsis. Surviving ratio of severe sepsis treated with activated protein C in one university intensive care unit during 2003–2006 Available online http://ccforum.com/supplements/11/S2 Materials and methods From January 2003 to August 2006 we used APC to treat 44 severely septic patients in our ICU. We obtained complete data for 37 patients. We collected data from the case notes, ICU charts and drotrecogin alfa (activated) data forms and recorded relevant data on an Excel spreadsheet proforma. Results NICE guidelines. We were 100% compliant with patient selection criteria for APC administration, which included a known or suspected site of infection, SIRS criteria and organ dysfunction criteria. All prescriptions were made by intensive care consultants. We were not fully compliant in excluding patients who met exclusion criteria (2/37 patients), although these cases were justified clinically by the consultants prior to administration. Data entry. In 90% of cases the patient selection fields were completed, but only 30% of the exclusion and outcome fields were completed. In 30% of patients where a lactate ≥1.5 times normal was listed as one of the inclusion criteria, it was not associated with a pH ≤7.30 or a base deficit ≥5.0; however, all these patients had ≥3 organ-dysfunction criteria and hence still met the inclusion criteria. Outcomes. Seven patients (15.9%) died during or within 28 days of APC administration. The standardised mortality ratio (SMR) was lower in patients receiving APC when compared with the rest of patients admitted over the same period (SMR ~0.5 vs ~1.0). Twenty-eight patients had an APACHE II score <25 and the effective cost per survivor was ~€16,800. Patients with APACHE II scores ≥25 had an effective cost per survivor of ~€22,400. Nine patients (20.5%) had their drotrecogin alfa (activated) infusions interrupted or discontinued for various reasons (including seven patients who had hemorrhagic complications, three of which were serious). respect to its use. The aim of this study was to demonstrate the safety profile and efficacy of DrotAA treatment within a large, 29- bed university hospital critical care unit. respect to its use. The aim of this study was to demonstrate the safety profile and efficacy of DrotAA treatment within a large, 29- bed university hospital critical care unit. Materials and methods From January 2003 to August 2006 we used APC to treat 44 severely septic patients in our ICU. We obtained complete data for 37 patients. We collected data from the case notes, ICU charts and drotrecogin alfa (activated) data forms and recorded relevant data on an Excel spreadsheet proforma. A large, single-centre UK registry of drotrecogin alfa-activated use L Macchiavello, G Ellis, S Bowden, M Smithies University Hospital of Wales, Cardiff, UK Critical Care 2007, 11(Suppl 2):P58 (doi: 10.1186/cc5218) Introduction As one of the few treatment interventions to demonstrate mortality efficacy at a randomized controlled trial level [1], the prescription of drotrecogin alfa-activated (DrotAA) (Xigris™), where appropriate, plays an important role in the management of severe sepsis. However, concerns regarding the potential for serious bleeding events have helped sustain a degree of scepticism regarding the use of DrotAA [2]. As early adopters of evidence-based medicine, Cardiff Critical Care Unit has prescribed DrotAA since late 2002 and has considerable experience with Interpretation All results were consistent with PROWESS, but need to be interpreted with caution due to their nonrandomised nature and the potential existence of important unknown confounders. In addition, the fact that only one in 16 potentially suitable admissions received DrotAA suggests a strong possibility for treatment bias. S22 References 1. Bernard GR, Vincent JL, Laterre PF, et al.: Efficacy and safety of recombinant human activated protein C for severe sepsis. N Engl J Med 2001, 344:699-709. 1. Bernard GR, Vincent JL, Laterre PF, et al.: Efficacy and safety of recombinant human activated protein C for severe sepsis. N Engl J Med 2001, 344:699-709. 1. Bernard GR, Vincent JL, Laterre PF, et al.: Efficacy and safety of recombinant human activated protein C for severe sepsis. N Engl J Med 2001, 344:699-709. C Cameron, W Plaxton Grand River Hospital, Kitchener, Canada Critical Care 2007, 11(Suppl 2):P60 (doi: 10.1186/cc5220) ritical Care 2007, 11(Suppl 2):P60 (doi: 10.1186/cc522 2. Mackenzie AF: Activated Protein C: do more survive? Inten- sive Care Med 2005, 31:1624-1626. 2. Mackenzie AF: Activated Protein C: do more survive? Inten- sive Care Med 2005, 31:1624-1626. 2. Mackenzie AF: Activated Protein C: do more survive? Inten- sive Care Med 2005, 31:1624-1626. Introduction Grand River Hospital (GRH) is a 495-bed non- teaching, acute care referral center in Southwestern Ontario, supporting regional programs including dialysis, oncology, surgery and stroke thrombolysis. Since the introduction of drotrecogin alfa (activated) (DAA) in 2003, GRH has treated 58 patients with this agent for severe sepsis and septic shock. We sought to compare, where possible, GRH ICU/hospital outcomes and bleeding complications with those from published literature. Available online http://ccforum.com/supplements/11/S2 Methods Demographic data were obtained from the unit’s daily updated Riyadh ICU programme database and clinical data were collected from patients’ medical notes and observation charts. All data were prospectively entered into our DrotAA registry, the results of which are shown below. Results NICE guidelines. We were 100% compliant with patient selection criteria for APC administration, which included a known or suspected site of infection, SIRS criteria and organ dysfunction criteria. All prescriptions were made by intensive care consultants. We were not fully compliant in excluding patients who met exclusion criteria (2/37 patients), although these cases were justified clinically by the consultants prior to administration. Results Between October 2002 and November 2005, 133 patients with severe sepsis were treated with DrotAA. The mean age was 61 years (range: 20–87 years) and 54% were male. The mean admission APACHE II score was 22 (range: 11–48), and on day 1 of DrotAA infusion the median number of organs that failed was 2.0 (range: 0–4), 129/133 (97%) were mechanically ventilated and 131/133 (98.5%) were on vasopressors. The median time to start DrotAA after documented diagnosis of severe sepsis was 12.6 hours (range: 0–41 hours) and the median duration of DrotAA infusion was 89.5 hours (range: 10–105 hours). The incidence of serious (life-threatening) bleeding events was 2.3% (n = 3): gastrointestinal (n = 1), intraabdominal (n = 1) and intrathoracic (n = 1); all were nonfatal and there were no intracranial bleeds. The 28-day mortality was 31.6%, the ICU mortality was 33.1%, the hospital mortality was 36.8% and the 1-year mortality was 47%. Data entry. In 90% of cases the patient selection fields were completed, but only 30% of the exclusion and outcome fields were completed. In 30% of patients where a lactate ≥1.5 times normal was listed as one of the inclusion criteria, it was not associated with a pH ≤7.30 or a base deficit ≥5.0; however, all these patients had ≥3 organ-dysfunction criteria and hence still met the inclusion criteria. g y Outcomes. Seven patients (15.9%) died during or within 28 days of APC administration. The standardised mortality ratio (SMR) was lower in patients receiving APC when compared with the rest of patients admitted over the same period (SMR ~0.5 vs ~1.0). Twenty-eight patients had an APACHE II score <25 and the effective cost per survivor was ~€16,800. Patients with APACHE II scores ≥25 had an effective cost per survivor of ~€22,400. P60 Retrospective observational outcomes for drotrecogin alfa (activated) Retrospective observational outcomes for drotrecogin alfa (activated) References Available online http://ccforum.com/supplements/11/S2 Nine patients (20.5%) had their drotrecogin alfa (activated) infusions interrupted or discontinued for various reasons (including seven patients who had hemorrhagic complications, three of which were serious). Conclusions This is one of the largest UK registries of DrotAA usage published to date. Our results demonstrate a very low incidence of serious bleeding events associated with DrotAA treat- ment (2.3% vs 3.5% in PROWESS); it is interesting to note that all three adverse events occurred prior to 2004. This detail, combined with our low median time to start DrotAA infusion (which has steadily decreased over the past 4 years), would suggest the presence of a learning curve for DrotAA usage on ICUs. It is also encouraging to note that our overall hospital mortality was lower than the predicted APACHE II hospital mortality for these patients (36.8% vs 42.4%). Finally, this is one of the first UK studies to describe long-term mortality outcome in patients receiving DrotAA therapy. Further studies are required to more formally assess the impact of DrotAA treatment on long-term survival from severe sepsis. Conclusions and recommendations We use APC in compliance with the NICE guidelines. APC is cost-effective in patients with an APACHE II score <25 in our ICU. 1. Bernard GR, et al.: N Engl J Med 2001, 334:699-709. 2. National Institute of Clinical Excellence [http://www.nice. org.uk/guidance/TA84] 2. National Institute of Clinical Excellence [http://www.nice. org.uk/guidance/TA84] P62 P62 59.4 years. Primary sources of infection were: intra-abdominal 36.2%, respiratory 27.6%, genitourinary 8.6%, and 27.6% from other sources. GRH ICU mortality was 44.8% and hospital mortality was 51.7%. Analysis by age revealed overall survival rates of 78.6% for patients ≤50 years, 54.5% for 51–60 years, 52.9% for 61–70 years, 20% for 71–80 years, and 0% for patients >80 years of age. Hemorrhagic complication rates were higher than in published reports. Of 58 treatments, we recorded a total of nine hemorrhages (15.5%). The mortality rate in this cohort was 33.3%. Conclusions These data suggest that ‘field performance’ of DAA may not be replicating the favorable clinical endpoints as reported in PROWESS. The Ontario Ministry of Health should consider implementing a provincial registry system for patients with severe sepsis and septic shock, empowering ICUs to track relevant demographic, acuity, and outcome data with a view to optimizing DAA use through patient selection and risk stratification. 59.4 years. Primary sources of infection were: intra-abdominal 36.2%, respiratory 27.6%, genitourinary 8.6%, and 27.6% from other sources. GRH ICU mortality was 44.8% and hospital mortality was 51.7%. Analysis by age revealed overall survival rates of 78.6% for patients ≤50 years, 54.5% for 51–60 years, 52.9% for 61–70 years, 20% for 71–80 years, and 0% for patients >80 years of age. Hemorrhagic complication rates were higher than in published reports. Of 58 treatments, we recorded a total of nine hemorrhages (15.5%). The mortality rate in this cohort was 33.3%. Conclusions These data suggest that ‘field performance’ of DAA may not be replicating the favorable clinical endpoints as reported in PROWESS. The Ontario Ministry of Health should consider implementing a provincial registry system for patients with severe sepsis and septic shock, empowering ICUs to track relevant demographic, acuity, and outcome data with a view to optimizing DAA use through patient selection and risk stratification. Three years experience with drotrecogin alfa (activated) protein C in severe sepsis and septic shock at Salmaniya Medical Complex, Bahrain H Mohamed, AA Hameed, M Al-Ansari Salmaniya Medical Complex, Manama, Bahrain Critical Care 2007, 11(Suppl 2):P62 (doi: 10.1186/cc5222) Objective To evaluate the role of activated protein C (APC) in severe sepsis and septic shock. Method The data were collected in a prospective manner from July 2002 to November 2006 in the adult medical/surgical ICU at Salmaniya Medical Complex Bahrain. The number of demographic variables were collected from patients’ files. Risk/benefit analysis of activated protein C in patients with intra-abdominal sepsis E Borthwick, D Stewart, E Mackle, C McAllister Craigavon Area Hospital, Co. Armagh, UK Critical Care 2007, 11(Suppl 2):P61 (doi: 10.1186/cc5221) E Borthwick, D Stewart, E Mackle, C McAllister Craigavon Area Hospital, Co. Armagh, UK Out of the total 444 septic patients 149 were assessed for APC; in the 85 patients fulfilling criteria for and receiving APC the mortality was 43.5%, and for the 64 patients not receiving APC the mortality was 64%. All suspected septic patients admitted to the ICU received appropriate antibiotic therapy within 4 hours of ICU admission and were upgraded/changed according to culture/ sensitivity reports if necessary. In the nonreceiving group (i.e. 64 patients) 12 patients could not receive APC due to financial restriction because initially foreigners were not entitled to this drug in Bahrain, but later this restriction was removed, and the remaining 52 patients could not receive either due to bleeding or very recent surgeries. Some patients could not receive complete treatment either due to bleeding complications or because they died. The mortality was measured at 28 days. Introduction and objective To establish whether activated protein C (APC) is safe in surgical patients with intra-abdominal sepsis (IAS). APC has been used in the treatment of IAS in our hospital since 2003. Fears persist regarding the potential for clinically significant bleeding in this surgical subgroup of patients. Methods Forty-four patients with IAS received APC as a standardized regime between March 2003 and August 2006. A retrospective medical and ICU chart review was undertaken. Data collected included clinically significant bleeding episodes and mortality. Descriptive subgroup analysis of unexpected non- survivors(died in the ICU with APACHE II (APII) predicted mortality < 50%) and unexpected survivors (survived to ICU discharge with APII predicted mortality > 50%) was performed as statistical analysis of such small patient numbers was inappropriate. Furthermore, as per our experience, if APC started in the early stage of sepsis and the course is completed the outcome is better – out of 85 patients who received APC, 45 patients received in the early stage and completed the dose and 32 of these patients survived at 28-day mortality. An average three (ventilator-free) organs failed in the survival group and two (ventilator-free) organs failed in the expired group. Risk/benefit analysis of activated protein C in patients with intra-abdominal sepsis Seventeen patients started treatment in the early stage and could not complete the course due to bleeding or other complications, 11 patients expired; 13 patients started in the late stage and completed the course, five patients expiring; and 10 patients started in the late stage and eight of these patients expired. Results There was one episode of clinically significant bleeding (from a mucous fistula: self-limiting). There were no intracranial haemorrhagic events. ICU mortality was 38.6% with mean APII predicted mortality of 37.16% and inhospital mortality of 47.7%. These exceeded rates for APC-treated surgical cohorts in the literature [1]. Unexpected survivors (5/44) were more likely to have been admitted from theatre. They had a shorter mean time from hospital–ICU admission (10.5 vs 5.6 days), duration on a ventilator (10.8 vs 17.5 days), vasopressor (9 vs 17.7 days) and renal replacement therapy (10.5 vs 23.5 days) dependence. All un- expected nonsurvivors (11/44) had a diagnosis of fistula or perforation. They were more likely to have been transferred to the ICU from another hospital or ward than from theatre. Co- morbidities were more severe. Conclusion On the basis of our experience and the results of multiple trials, we recommend APC should be given to the patients who meet all the inclusion criteria. Conclusion 1. APC was very safe to use in this group of critically ill surgical patients. 2. Although patients may fulfil standard criteria for APC use, if there is no definitive surgical cure for the IAS, then APC is inappropriate. 3. Delay in commencement of APC in surgical patients due to bleeding concerns may be contributing to the high mortality. Earlier perioperative use of APC in selected cases may offer improved mortality benefit, and we are undertaking a prospective audit to investigate this. P62 Results A total of 444 patients were admitted to the ICU with the diagnosis of sepsis or severe sepsis. One hundred and forty-nine severe septic patients were assessed for APC: 85 patients received APC, and 64 patients could not receive APC due to financial problems or due to bleeding, coagulation derangement or very recent surgeries. In the total 444 septic patients admitted to the ICU, 152 patients expired (mortality 34.2%) and 141 had positive blood culture; 233 patients received inotrops. The total average APACHE II score was 28.9 and for expired patients was 35.1. P59 Audit of adherence to National Institute of Clinical Excellence guidelines for the use of drotrecogin alfa (activated) Excellence guidelines for the use of drotrecogin alfa (activated) R Vedantham, B Iyowu University Hospital Lewisham, London, UK Critical Care 2007, 11(Suppl 2):P59 (doi: 10.1186/cc5219) R Vedantham, B Iyowu University Hospital Lewisham, London, UK Critical Care 2007, 11(Suppl 2):P59 (doi: 10.1186/cc5219) R Vedantham, B Iyowu University Hospital Lewisham, London, UK Critical Care 2007, 11(Suppl 2):P59 (doi: 10.1186/cc5219) Methods All charts for patients treated with DAA in our CAICU for severe sepsis and septic shock between February 2003 and June 2006 were reviewed retrospectively for infection source, ICU/ hospital mortality, survival by age and incidence of hemorrhagic complications. Where possible, we compare our data with those from PROWESS, ENHANCE and a recent Ontario/Quebec-based multicenter usage evaluation. A two-organ system failure threshold for DAA consideration is used. Outcomes were categorized as ICU mortality and hospital mortality, as opposed to 28-day mortality used in PROWESS and ENHANCE. Introduction Activated protein C (APC) is an endogenous protein, which has fibrinolytic and anti-inflammatory properties. This is available as human recombinant APC and is used in the treatment of patients with severe sepsis [1]. The National Institute of Clinical Excellence (NICE) suggested guidelines for the use of APC [2]. We retrospectively audited the records of patients who received APC during their admission to our ICU between January 2003 and August 2006. We audited our practice against three parameters: compliance with the NICE guidelines, accuracy of data forms, and outcomes of treatment. Results All 58 patients who received DAA at GRH were included in our analysis. The mean age of patients treated with DAA was Results All 58 patients who received DAA at GRH were included in our analysis. The mean age of patients treated with DAA was S23 P61 Risk/benefit analysis of activated protein C in patients with intra-abdominal sepsis Risk/benefit analysis of activated protein C in patients with intra-abdominal sepsis Available online http://ccforum.com/supplements/11/S2 Results Overall, 12,492 patients with severe sepsis from 37 countries were enrolled and 882 (7%) patients received DAA therapy. The highest rate of use of DAA was seen in the United States at 27% (206/760). Patients who received DAA versus those who did not receive DAA were younger (median age 59 versus 64 years), had greater organ dysfunction (cardiovascular dysfunction (90% versus 74%), respiratory dysfunction (90% versus 81%), renal dysfunction (60% versus 45%), metabolic abnormalities (63% versus 42%), three or more organ dys- functions (84% versus 67%)) and higher median APACHE II scores (25.0 vs 23.0), all P < 0.001. The mortality rate for patients treated with DAA was 49.6% and for those not treated with DAA was 49.7%. Although imbalances in other baseline characteristics, not collected in PROGRESS, may have also been present, when adjusted for age and number of organ dysfunctions the odds ratio for hospital mortality associated with DAA use was 0.75 (0.63–0.90, P = 0.002). Methods Fifty-seven patients with severe sepsis (age 51 ± 15 years, range 20–77 years, male:female 32:25) admitted to the ICU were included. All patients had three or more signs of systemic inflammation with at least two major organ dysfunctions or the presence of ARDS. Demographic, clinical and laboratory profiles at baseline, and during the hospital stay, development of complica- tions, duration of hospital/ICU stay and hospital survival were recorded. All management decisions including initiation of DA (24 µ/kg/hour), duration of treatment as well as its discontinuation were the prerogative of the ICU team. Results The majority of patients had a confirmed infection (n = 36, 63.2%), with the commonest site of focus being the lung (n = 25, 43.9%) followed by the abdomen (n = 13, 22.8%). A significant number of patients had at least three major organ dysfunctions (n = 37, 64.9%). A large number of patients had an APACHE II score in the range 25–29 (n = 22, 38.6%). Whereas 44 patients (77.2%) were on some kind of vasopressor support, 51 needed ventilatory support (89.5%). A total of 20 patients (35.1%) survived to hospital discharge. Patients received DA for a mean duration of 74.8 ± 26.2 hours (range 25–96 hours) and only 32 patients could complete treatment (56.1%). The outcome was significantly better in patients who could complete therapy (53.1% vs 13.6%, P = 0.001). Available online http://ccforum.com/supplements/11/S2 Major bleeding necessitating discontinuation was seen in four patients (7%) whereas the other 21 patients (36.9%) died before completing 96 hours of therapy. DA was initiated within 48 hours of development of organ dysfunction in the majority of patients (n = 31, 54.4%), and a trend towards better outcome in patients with early treatment was noted although the difference did not reach statistical significance (mortality rate 58% for early treatment vs 73.1% for delayed treatment, P = not significant). Conclusion In a large global registry, patients receiving DAA therapy were younger with higher disease severity than patients not treated with DAA. When adjusted for age and number of organ dysfunctions, DAA was associated with a reduction in the odds of hospital mortality similar to that seen at day 28 in PROWESS. These data are supportive of the effectiveness of DAA in clinical practice. Epidemiology of severe sepsis in India S Todi, S Chatterjee, M Bhattacharyya AMRI Hospitals, Kolkata, India Critical Care 2007, 11(Suppl 2):P65 (doi: 10.1186/cc5225) Conclusion Mortality of patients with severe sepsis remains high despite the introduction of DA. Early institution may be associated with better outcomes. Patients receiving a complete course of treatment have better survival. Introduction A multicentre, prospective, observational study was conducted in 12 intensive therapy units (ITUs) in India from June 2006 to November 2006 to determine the incidence and outcome of severe sepsis among adult patients. P64 Methods All patients admitted to ITUs were screened daily for SIRS, organ dysfunction and severe sepsis. Patients with severe sepsis were further studied. Drotrecogin alfa in patients with severe sepsis: experience from a tertiary care center in North India Drotrecogin alfa in patients with severe sepsis: experience from a tertiary care center in North India R Chawla, S Kansal, A Lall, M Kanwar, D Rosha, A Bansal, V Sikri Indraprastha Apollo Hospitals, New Delhi, India Critical Care 2007, 11(Suppl 2):P63 (doi: 10.1186/cc5223) Introduction Drotrecogin alfa (DA) remains the only approved drug for the specific treatment of severe sepsis. Although it has been in wide clinical usage, there are no data on its use in Indian patients. 1. Barie PS, et al.: Benefit/risk profile of drotAA in surgical patients with severe sepsis. Am J Surg 2004, 188:212- 220. S24 Available online http://ccforum.com/supplements/11/S2 Severe sepsis and drotrecogin alfa (activated) use: results from the PROGRESS registry Results A total of 1,344 ITU admissions were studied. There were no SIRS in 31.3% and SIRS without organ dysfunction in 51.6%. SIRS with organ dysfunction was found in 230 (17.1%) patients, of which 54 (23.5%) were not due to sepsis and 176 (76.5%) were due to sepsis. The incidence of severe sepsis was 13.1% of all admissions. The mean age of the study population was 54.9 years (SD 17.6), of which 67% were male. The median APACHE II score was 22 (IQR 17–28) with predominant (88%) medical admission. ITU mortality of all admissions was 13.9% and that of R Beale1, F Brunkhorst2, G Martin3, M Williams4, D Nelson4, J Janes4 1St Thomas’ Hospital, London, UK; 2Friedrich-Schiller University, Jena, Germany; 3Emory University School of Medicine, Atlanta, GA, USA; 4Lilly Research Laboratories, Indianapolis, IN, USA Critical Care 2007, 11(Suppl 2):P64 (doi: 10.1186/cc5224) Introduction Since the launch of drotrecogin alfa (activated) (DAA) a number of institutions and countries have published data on its use in clinical practice, based on audit or registry data. Such publications have tended to report DAA use in higher disease severity populations together with higher mortality outcomes compared with clinical trials. We utilized the Global PROGRESS (Promoting Global Research Excellence in Severe Sepsis) database to examine the baseline characteristics and outcome of patients with and without DAA treatment. Figure 1 (abstract P65) P66 PISA: the prevalence of infection in intensive care units in South Africa S Bhagwanjee, J Scribante, H Perrie, F Paruk University of the Witwatersrand and the CCSSA, Johannesburg, South Africa Critical Care 2007, 11(Suppl 2):P66 (doi: 10.1186/cc5226) PISA: the prevalence of infection in intensive care units in South Africa R Goldwasser1, C David1, R Hatum2, J Salles2, O Barbosa3, C Piras4, M Braga5, G Macedo6, G Fundo7 1Hospital Universitario-Universidade Federal do Rio de Janeiro, Brazil; 2HCN, Niteroi, Brazil; 3Hospital Santa Joana, Recife, Brazil; 4Hospital São Lucas, Vitoria, Brazil; 5Hospital Biocor, Belo Horizonte, Brazil; 6Hospital Universitario Sul Fluminense, Vassouras, Brazil; 7AMIB, São Paulo, Brazil Critical Care 2007, 11(Suppl 2):P67 (doi: 10.1186/cc5227) R Goldwasser1, C David1, R Hatum2, J Salles2, O Barbosa3, S Bhagwanjee, J Scribante, H Perrie, F Paruk University of the Witwatersrand and the CCSSA, Johannesburg, South Africa Critical Care 2007, 11(Suppl 2):P66 (doi: 10.1186/cc5226) Introduction Sepsis in the ICU is a major cause of morbidity and mortality. In addition it increases the direct and indirect cost of care. Effective intervention to improve patient outcome and ensure optimal use of resources depends on the availability of data. No epidemiological data are available on the prevalence of sepsis in South Africa. This study was a 1-day sepsis prevalence study conducted in an attempt to address this lack of data. Introduction Sepsis occurs in 16.6% of the patients in the Brazilian ICU and is associated with a high mortality rate (46.6%). Several studies show different pathogenic agents among countries and increased antibiotic resistance. This study aims to describe the pathogen profile in Brazil’s ICU septic patients. Introduction Sepsis occurs in 16.6% of the patients in the Brazilian ICU and is associated with a high mortality rate (46.6%). Several studies show different pathogenic agents among countries and increased antibiotic resistance. This study aims to describe the pathogen profile in Brazil’s ICU septic patients. g Methods A prospective cohort study involving 75 ICUs all over Brazil was performed. All patients who were admitted or developed sepsis during a 1-month period were enrolled and followed until the 28th day and/or until their discharge. Method Following appropriate institutional approval, 43 ICUs were selected using the proportional probability sampling technique. This was applied to a national database of ICUs. Every seventh bed was selected from all the serially placed units. P67 P67 Microbiology profile of sepsis in Brazil Figure 1 (abstract P65) Methods PROGRESS is a global, noninterventional, multicenter, prospective, observational study of severe sepsis patients treated in ICUs. Patients must have had a diagnosis of severe sepsis and have been treated in an ICU at a participating institution. All treat- ment modalities were as per standard of care at the participating institutions. We analyzed baseline characteristics and hospital mortality. We also performed an adjusted mortality analysis for DAA patients due to baseline imbalances in patients with and without DAA therapy. S25 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine Table 1 (abstract P66) Diagnostic concordance Treating doctor Assessors None 169 54 SIRS 16 120 Sepsis 36 41 Severe sepsis 7 12 Septic shock 9 16 severe sepsis was 54.1%. Hospital mortality and 28-day mortality of severe sepsis were 59.3% and 57.6%, respectively. The standardized mortality ratio of severe sepsis patients was 1.40. The median duration of stay in ITUs of the severe sepsis cohort who survived was 6 days (IQR 3–12). The number of episodes where infection was the primary reason for admission to the ITU was 89.8% and the rest of episodes were ITU acquired. See Figure 1 for infection characteristics. severe sepsis was 54.1%. Hospital mortality and 28-day mortality of severe sepsis were 59.3% and 57.6%, respectively. The standardized mortality ratio of severe sepsis patients was 1.40. The median duration of stay in ITUs of the severe sepsis cohort who survived was 6 days (IQR 3–12). The number of episodes where infection was the primary reason for admission to the ITU was 89.8% and the rest of episodes were ITU acquired. See Figure 1 for infection characteristics. Conclusion Sepsis was common in Indian ITUs and had predominant medical populations. ITU mortality was higher compared with western literature. Gram-positive infections were less common although the incidence of parasitic and viral infections were higher than in the West. P66 Data collected identified the profile of the unit and the patient details for the day in question (15 August 2005). The primary endpoint was a peer- reviewed determination of the need for antibiotic prescription as determined by two independent reviewers. Sepsis was defined according to the ACCP/SCCM criteria. Secondary end-points included determination of diagnostic ability of attending clinicians, antibiotic prescribing patterns and appropriateness of modification of therapy based on microbiological data. Results A total of 521 patients filled the criteria of sepsis and were studied. The two main sources of infection were pneumonia and the abdominal tract. Gram-negative bacteria were isolated in 40.1%, followed by Gram-positive (38.8%) and fungus (5%). The most prevalent bacteria were Staphylococcus aureus (31.3%) and Pseudomonas aeruginosa (26.8%). Methicilin-resistant Staphylo- coccus aureus (MRSA) were present in 64.8%. Bacteria were isolated in blood samples in 19.57% and S. aureus was prevalent. The prevalence of antimicrobial-resistant bacteria was 26.6% and was associated with higher mortality at the 28th day (resistant bacteria 50.9% vs nonresistant bacteria 43.5%). Septic shock was related to the highest mortality, with rates ranging from 45.8%, 63.7% and 83.3% due to S. aureus, P. aeruginosa and Acineto- bacter spp, respectively. Results The mean age of patients was 55 years (n = 248) with a male:female ratio of 60:40. Sixty-eight per cent of patients were admitted post surgery. There was reasonable concordance for sepsis, severe sepsis and septic shock (Table 1). A total of 196/248 (79%) patients were deemed to require antibiotics by the attending clinician, compared with 69/248 (28%) who were deemed to have sepsis by independent review. Fifty-one per cent of patients were inappropriately diagnosed as having sepsis. The commonest site of sepsis (as determined by the assessors) was the lung (45%) followed by the abdomen (10%). In 42% of cases antimicrobial prescription was adjudged as being appropriate, while in 11% of cases antimicrobials were appropriately modified following microbiology results. The duration of therapy was appropriate in 26% of cases. Conclusions Gram-negative bacteria were the most frequently isolated pathogens in the ICU in septic patients. MRSA represented the majority of S.aureus strains isolated. Antibiotic- resistant bacteria were associated with higher mortality. It is important to recognize the Brazilian ICU organisms’ profile and their resistance pattern to guide rational administration of antimicrobial agents. Implementation of early goal-directed therapy in Finland Implementation of early goal-directed therapy in Finland M Varpula Helsinki University Hospital, Kauniainen, Finland Critical Care 2007, 11(Suppl 2):P69 (doi: 10.1186/cc5229) Introduction The early recognition and rapid start of goal-directed treatment (EGDT) are important elements for better outcome in severe sepsis. These actions should take place in the emergency department (ED) before admission to the ICU. The aim of our study was to determine how the EGDT was performed and to evaluate the impact of EGDT principles on mortality in septic shock in Finland. Our study was conducted before national guidelines for severe sepsis were published. Results There were 201 patients admitted to the unit during the period of our study; 140 of these were neurosciences (NS) patients and the rest (61) were general (G) (either medical or surgical). Most of the patients were men and had a mean APACHE II score of 39 (NS group 33, G group 45).There were in total 64 episodes of positive blood cultures (BC); 39 of these episodes were accompanied by inflammatory signs (incidence of blood- stream infections of 19.4% of total admissions). Twenty-five of the episodes were not associated to clinical signs of infection. There were more patients with at least one episode of positive BC in the NS group (29 (20.7%)) than in the G group (10 (16.39%)). Out of 49 episodes in the NS group, 59.18% (29) were associated to some degree of inflammatory response (SIRS, severe sepsis, and MODS). Out of 15 episodes in the G group, 66.6% (10) developed inflammatory response. In 59% (25) of the positive BCs, the organism isolated was coagulase-negative staphylo- coccus (CNS). In the G group, 47% (7) grew CNS, 33% were diverse Gram-negatives and in 20% other Gram-positives. In the NS group, 64% (31) of isolates grew CNS, 21% were other Gram- positives and 15% were Gram-negatives. In 47 (73.4%) episodes of positive BC, the patients had either a central venous catheter or an arterial catheter. In 36 (56.2%) of the episodes the patients were already on antibiotics at the time of the sampling. The most frequent agent isolated was coagulase-negative Staphylococcus aureus, in 39 (59%) of the cases. Methods A prospective observational study of patients with severe sepsis and septic shock admitted to 21 ICUs in Finland from 1 November 2004 to 28 February 2005 (Finnsepsis). Implementation of early goal-directed therapy in Finland Only patients with community-acquired sepsis, who fulfilled the criteria of septic shock and were admitted directly from the ED to the ICU, were included. The following treatment targets were evaluated: (1) measurement of lactate during the first 6 hours from admission to the ED; (2) obtaining the blood cultures before antibiotics; (3) starting the antibiotics within 3 hours from admission; and reaching the (4) mean arterial pressure over 65 mmHg, (5) central venous pressure over 8 mmHg and (6) central venous oxygen saturation over 70% or mixed venous oxygen saturation over 65% during the first 6 hours with fluids and vasopressors. Results Sixty-three patients were included. The median age was 57 years (IQR 18.5) and the median APACHE II score was 28 (IQR 10). The ICU, hospital and 1-year mortality rates were 25%, 38% and 52%, respectively. Only five (8%) patients reached all treatment targets and 24 patients (38%) reached four or more targets (group A). The hospital mortality of group A was 29% (95% CI 15–49%) compared with 44% (95% CI 29–59%) of those who reached only three or less targets (group B) (P = 0.3). The median delay from ED arrival to ICU admission in group A and group B was 1.1 and 3.7 hours (P < 0.001), and the median SOFA score for the first day was 10 and 11 (P = 0.4), respectively. The median APACHE II score was 28 in both groups (P = 0.9). In multivariate analysis including all separate targets, delay for ICU admission and APACHE II score, the APACHE II value and measurement of lactate were independent predictors of mortality (P = 0.001 and 0.02). Only 18% of patients had serum lactate measured during the ED stay. The 1-year mortality of group A was 42% (95% CI 24–61%) and of group B was 59% (95% CI 43–73%) (P = 0.2). The hospital mortality of group A was 29% (95% CI 15–49%) compared with 44% (95% CI 29–59%) of those who reached only three or less targets (group B) (P = 0.3). The median delay from ED arrival to ICU admission in group A and group B was 1.1 and 3.7 hours (P < 0.001), and the median SOFA score for the first day was 10 and 11 (P = 0.4), respectively. The median APACHE II score was 28 in both groups (P = 0.9). Available online http://ccforum.com/supplements/11/S2 unit (NCCU) is at the moment unknown. It is known that being a patient in the intensive care environment is in itself a risk factor for the development of bacteraemia (3.2–4.1 per 100 admissions in several papers). The higher amount of invasive procedures and the severity of illness in this group of patients have been blamed. The aims of our study are: (1) to identify the incidence of bacteraemia in the NCCU, (2) to recognise the incidence of bloodstream infection (SIRS with bacteraemia), (3) to identify the most common pathogens associated with bacteraemia, and (4) to promote the continuous collection of data aiming to follow the behaviour of this problem in time. unit (NCCU) is at the moment unknown. It is known that being a patient in the intensive care environment is in itself a risk factor for the development of bacteraemia (3.2–4.1 per 100 admissions in several papers). The higher amount of invasive procedures and the severity of illness in this group of patients have been blamed. The aims of our study are: (1) to identify the incidence of bacteraemia in the NCCU, (2) to recognise the incidence of bloodstream infection (SIRS with bacteraemia), (3) to identify the most common pathogens associated with bacteraemia, and (4) to promote the continuous collection of data aiming to follow the behaviour of this problem in time. patients was almost the same for both groups. We noted, as well, a larger number of deaths in the patients with sepsis and MOF. There needs to be more studies aiming to establish a casual relationship to explain this. CNS was the most frequently isolated organism and there was no difference among the groups. There is a potential for increased mortality in the patients that develop bloodstream infections in our unit, and we need to implement urgent measures to decrease them while further research is done in this area. P68 Conclusion The national prevalence of sepsis, the site of sepsis and the patient profile in South Africa is similar to that described in other studies [1]. Treating doctors are reasonably accurate in diagnosing sepsis but prescribe antiobiotics inappropriately in the vast majority of cases. Incidence of bacteraemia in a neurocritical care unit L Colorado, M Vizcaychipi, S Herbert, O Sule, R Burnstein Addenbrooke’s Hospital, Cambridge, UK Critical Care 2007, 11(Suppl 2):P68 (doi: 10.1186/cc5228) 1. An expert report of the European Society of Intensive Care Medicine. The problem of sepsis. Intensive Care Med 1994, 20:300-304. 1. An expert report of the European Society of Intensive Care Medicine. The problem of sepsis. Intensive Care Med 1994, 20:300-304. Introduction The incidence of bacteraemia and bloodstream infection, as defined by the CDC, in our neurosciences critical care S26 Available online http://ccforum.com/supplements/11/S2 P69 Methods This is a prospective observational study looking at the presence of positive blood cultures in all the patients admitted to the NCCU during the period from 1 June to 31 August 2006. Blood cultures were taken from a peripheral site under aseptic conditions as per the NCCU guidelines. We tried to identify how many of the patients with positive blood cultures had evidence of concomitant SIRS/sepsis, as described by the modified Bone criteria, and the severity of this. An attempt was made to identify the most frequent microorganisms involved in this problem as well as their antibiotic susceptibility. As a secondary aim of our study we described the number of fatalities in the patients with bacteraemia. We tried to focus our approach to the fact that we serve a large neurological/surgical population as well as general patients and to see whether we could pinpoint differences in these two groups. Awareness of the Surviving Sepsis Campaign amongst emergency medicine and surgical trainees A Castellanos-Ortega, B Suberviola, A González-Castro, C Gonzalez, A Ruiz, J Teja, F Ortiz Hospital Universitario Marqués de Valdecilla, Santander, Spain Critical Care 2007, 11(Suppl 2):P70 (doi: 10.1186/cc5230) L Evans Queen Elizabeth Hospital, King’s Lynn, UK Critical Care 2007, 11(Suppl 2):P71 (doi: 10.1186/cc5231) Introduction Data presented at the 2006 Barcelona conference of the European Society of Intensive Care Medicine showed that, where implemented, the Surviving Sepsis Campaign guidelines have improved mortality from sepsis. However, because of overall poor adherence to the guidelines, the stated aim of the campaign to reduce mortality from severe sepsis by 25% is unlikely to be met. In the United Kingdom, patients with sepsis of surgical origin will typically be seen by emergency medicine (EM) before being admitted to a surgical ward and are unlikely to be initially managed by the ICU. Both the EM and surgical juniors should therefore be aware of the guidelines. The aim of this study was to determine the level of awareness of the SSC guidelines in surgical and EM trainees. Introduction The purpose of the study was to describe the effectiveness of the Surviving Sepsis Campaign (SSC) bundles with regard to both implementation and outcome in patients with septic shock. Methods This was a single-center prospective observational study of patients admitted to the medical–surgical ICU of an urban tertiary care teaching hospital meeting criteria for the international sepsis definitions. Patients were entered in the database from September 2005 to October 2006. After a widespread 2-month educational program, implementation of SSC Resuscitation Bundles (RB) and Management Bundles (MB) were accomplished. We determined the rate of compliance and the prognostic value of the RB, the MB and of each bundle element. g g Methods A questionnaire-based survey was undertaken of all EM and surgical trainees in the Eastern region of the United Kingdom. Participants were recruited by post, telephone, email and in person. The questionnaire assessed whether participants had experience in critical care, were aware of the campaign or its guidelines and assessed the level of familiarity of key concepts of the resuscitation bundle of the guidelines. In addition, participants were encouraged to comment on any aspect of sepsis management. Methods A questionnaire-based survey was undertaken of all EM and surgical trainees in the Eastern region of the United Kingdom. Participants were recruited by post, telephone, email and in person. Awareness of the Surviving Sepsis Campaign amongst emergency medicine and surgical trainees Th i i d h h i i h d i i Results We analyzed 135 consecutive episodes of septic shock. The main sources of infection were: abdomen 39.5%, lung 29.9%, and urinary tract infection 11.1%. Global hospital mortality was 44.4%. Nonsurvivors were older (71 vs 64 years; P = 0.01), and had a higher APACHE II score (25 vs 20; P = 0.000), a higher SOFA score (10 vs 9; P = 0.001) and a higher number or organ dysfunctions at sepsis presentation (4 vs 3; P = 0.007). The rate of compliance with the RB was 38%. There were significant differences in mortality between compliant (C) and noncompliant (NC) groups despite the similar characteristics and the severity of septic shock. The NC group had a 58% mortality rate and the C group 22% (RR 2.6 (95% CI 1.49–4.5, P = 0.001)). The number needed to treat to save one life was 3. The compliance rate with MB was only 20%, and there were no differences in mortality between the C and NC groups (57.9% vs 52.6%). We only found differences in mortality between the C and NC groups in four bundle elements: serum lactate measured before 6 hours (35.2% vs 65.4%; P = 0.007), early broad-spectrum antibiotics (36.2.5% vs 56.1%; P = 0.051), ScvO2 > 70% (35.7% vs 52.1%; P = 0.057) and activated protein C (65% vs 11% P = 0.000). In the multivariate analysis, activated protein C, early broad-spectrum antibiotics, PaO2/FiO2 < 200 and complete RB were associated independently with mortality. The questionnaire assessed whether participants had experience in critical care, were aware of the campaign or its guidelines and assessed the level of familiarity of key concepts of the resuscitation bundle of the guidelines. In addition, participants were encouraged to comment on any aspect of sepsis management. Results Summarised in Table 1. There are 29 EM and 52 surgical trainees in the Eastern region; responses were obtained from 22 and 34, respectively. The responses to the key concepts of the resuscitation bundle varied greatly, even between different participants from the same speciality in the same institution, suggesting a lack of clear direction. Free text responses included ‘the only people that know about guidelines for sepsis are the ICU physicians’ and ‘the only time I have heard of early goal directed therapy was on ER’. Conclusion Awareness is reasonable amongst EM trainees but poor amongst surgeons. P70 P70 P71 P71 Awareness of the Surviving Sepsis Campaign amongst emergency medicine and surgical trainees P72 Compliance rates with RB during three consecutive 4.6-month time periods were 28%, 41.4% and 33.3%, respectively. Compliance with MB was unchanged at 20%. The present dataset is underpowered to determine whether implementation of SSC bundles had some effect on mortality reduction. Awareness of the Surviving Sepsis Campaign amongst emergency medicine and surgical trainees If the aims of the SSC are to be met, consideration must be given to differences in healthcare systems in different countries. In the United Kingdom, educational activities should be directed towards EM and surgical trainees as well as those working in intensive care. Impact of sepsis care bundles on hospital mortality in 135 consecutive patients with septic shock Impact of sepsis care bundles on hospital mortality in 135 consecutive patients with septic shock Implementation of early goal-directed therapy in Finland In multivariate analysis including all separate targets, delay for ICU admission and APACHE II score, the APACHE II value and measurement of lactate were independent predictors of mortality (P = 0.001 and 0.02). Only 18% of patients had serum lactate measured during the ED stay. The 1-year mortality of group A was 42% (95% CI 24–61%) and of group B was 59% (95% CI 43–73%) (P = 0.2). Conclusions The adoption of EGDT protocol was poor in Finnish hospitals. The impaired early recognition of sepsis may lead to a delay in ICU admission. The rate of reached EGDT targets reflected mortality. In this study the most critical EGDT target was the measurement of lactate during first 6 hours after arrival in the ED. A forthcoming follow-up study will evaluate the impact of guidelines to treatment and outcome of septic shock in Finland. From the patients that had at least one positive BC, nine died; seven (78%) patients were in the G group, and two (22%) in the NS group. Twenty-five (68%) patients with at least one episode of positive BC had a systemic inflammatory response at the time of sampling. Seven (28%) of these died during the first 30 days in the NCCU. Nine (23%) patients had severe sepsis and four (44%) of these died. Four (10.2%) patients had MODS and three (75%) of these died. Conclusions We had an incidence of positive blood cultures of almost 32% of the total admissions; 19.4% of admissions developed bloodstream infections. These numbers are very high if we consider the published data. Due to the specialist origin of our unit, we had more cases in the neurosciences group than in the general group. However, the incidence of sepsis and MOF in these S27 Compliance with the surviving sepsis guidelines: a review of South African intensive care units S Bhagwanjee, F Paruk, J Scribante, H Perrie University of the Witwatersrand and the CCSSA, Johannesburg, South Africa Critical Care 2007, 11(Suppl 2):P72 (doi: 10.1186/cc5232) Conclusions Implementation of SSC bundles was associated with less adherence than expected. However, septic shock patients receiving the complete resuscitation bundle had substantially lower mortality. Efforts to increase compliance with these interventions should be made. The poor adherence to management bundles probably shows the many uncertainties that remain within this group of interventions. Introduction Despite the availability of guidelines for practice in many clinical domains, it is common for clinicians to practice outwith these guidelines. As part of a 1-day sepsis prevalence study in ICUs in South Africa, a review was undertaken to determine the Table 1 (abstract P71) Worked in ICU Claimed to be Able to name Any training on sepsis Claim to be Able to name piece of Trainees in past 2 years? aware of campaign SSC in past 2 years? aware of research relevant research Emergency medicine 8 (36%) 15 (68%) 10 (45%) 13 (59%) 13 (59%) 10 (45%) Surgery 2 (6%) 6 (18%) 3 (8%) 9 (26%) 13 (38%) 8 (24%) Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 extent to which units comply with the surviving sepsis guidelines as promulgated by the International Sepsis Forum [1]. Methods All adult patients with an APACHE III medical admission diagnosis of nonurinary or urinary sepsis, or nonurinary or urinary sepsis with shock, admitted directly to the ICU from the ED between 1 January 1997 and 31 December 2005 were identified. Predictor variables for hospital mortality were analysed using logistic regression with cross-validation (80% determination and 20% validation) and robust, cluster-specific (ICU site) standard errors. Method Following appropriate institutional approval, 43 ICUs were selected using the proportional probability sampling technique. This was applied to a national database of ICUs. Every seventh bed was selected from all the serially placed units. Data collected included the presence of an infection control policy (including guidelines for performance of blood cultures), recording of culture results, microbiological support structures, glucose control protocols and protocols for sedation analgesia and muscle relaxation. Results A total of 7,649 patients (54% male) of mean (SD) age 60.2 (18.1) years and APACHE III score 74.0 (34.7) were identified. The number of patients admitted per year increased progressively (1997, n = 368 (7.7 admissions per contributing ICU); 2005, n = 1,409 (14.0 admissions per contributing ICU)). Nonurinary sepsis with shock was the most common admission diagnosis (n = 3,394, 44.4%) and urinary sepsis with shock the least common (n = 607, 7.9%). Overall ICU mortality and hospital mortality were 20.9% and 27.6%, respectively. Hospital mortality was predicted by hospital type (tertiary: 0.67 (0.51–0.90), P = 0.007; metropolitan: 0.63 (0.48–0.83), P = 0.001; private: 0.65 (0.47–0.91), P = 0.011; reference category rural), age (1.026 (1.019–1.034), P = 0.0001), APACHE III score (1.043 (1.038–1.048), P = 0.0001) and APACHE III score squared (P = 0.032), sepsis category (nonurinary shock versus the other three categories combined, 1.79 (1.48–2.16), P = 0.001), mecha- nical ventilation within 24 hours of ICU admission (1.38 (1.14–1.66), P = 0.001) and calendar year as a single main linear effect (0.94 (0.90–0.97), P = 0.0001). Significant interactions were demonstrated between (i) sepsis classification and calendar year (linear decrease in mortality, nonurinary shock x year 0.92 (0.86–0.99), P = 0.019), (ii) sepsis classification and age (nonurinary shock x age 0.986 (0.977–0.996), P = 0.008), and (iii) ventilation and time from hospital to ICU admission (<4.5 hours or ≥4.5 hours 1.38 (1.12–1.69), P = 0.002). Clinical simulation: caring for a critically ill patient with sepsis Clinical simulation: caring for a critically ill patient with sepsis K Giuliano, A Johannessen, S Crockett Philips Medical Systems, Andover, MA, USA Critical Care 2007, 11(Suppl 2):P74 (doi: 10.1186/cc5234) Reference Reference 1. Dellinger RP, Carlet JM, Masur H, et al., for the Surviving Sepsis Campaign Management Guidelines Committee: Guidelines for the management of severe sepsis and septic shock. Crit Care Med 2004, 32:858-873. 1. Dellinger RP, Carlet JM, Masur H, et al., for the Surviving Sepsis Campaign Management Guidelines Committee: Guidelines for the management of severe sepsis and septic shock. Crit Care Med 2004, 32:858-873. 1. Dellinger RP, Carlet JM, Masur H, et al., for the Surviving Sepsis Campaign Management Guidelines Committee: Guidelines for the management of severe sepsis and septic shock. Crit Care Med 2004, 32:858-873. Introduction The purpose of this simulation research was to assess whether bedside nurses could better apply currently recommended therapeutic interventions for patients with sepsis by using a horizons trends clinical decision support tool, rather than just standard monitoring screen displays alone. Available online http://ccforum.com/supplements/11/S2 The model ROC curve area and the P value for the Hosmer–Lemeshow C statistic were 0.86 and 0.37, respectively. Restricting the model to only those ICUs that contributed data for all 9 years of the study period yielded similar parameter estimates, including calendar year effect. Conclusions The reported incidence of sepsis and septic shock in ICU patients presenting to the ED in Australia and New Zealand has increased since 1997; hospital mortality has decreased. These data require confirmation with a prospective study. Results Forty-three out of a total of 458 units were sampled. The mean age of patients was 55 years with a male:female ratio of 60:40. Sixty-eight per cent of patients were admitted post surgery. An infection control policy was present in 77% of units. A practice procedure for blood culture sampling was used in 51% of units, with records of culture results being documented in 56% of units. Microbiologists were available in 65% of units and they were involved in ward rounds in 26% of units. Physical consultation by a microbiologist in 47% of units and telephone consultations in 54% of units were possible. Sixty-one per cent of units had a glucose control policy. Sedation, analgesia and neuromuscular blockade protocols were present in 33%, 26% and 21% of units, respectively. See Table 1. Table 1 (abstract P72) Percentage of units utilizing protocols Domain Use (%) Microbiologist available 65 Infection control policy 77 Glucose control protocol 61 Sedation protocol 33 Analgesia protocol 26 Neuromuscular blockade protocol 21 Table 1 (abstract P72) Table 1 (abstract P72) Percentage of units utilizing protocols Domain Use (%) Microbiologist available 65 Infection control policy 77 Glucose control protocol 61 Sedation protocol 33 Analgesia protocol 26 Neuromuscular blockade protocol 21 Percentage of units utilizing protocols Conclusion The majority of units have an infection control policy, utilize glucose control regimens and have access to a microbiologist. Sedation, analgesia and neuromuscular blockade are infrequently utilized. Despite the availability of guidelines, it is common for many recommendations not to be implemented. Further work is required to determine the reasons for noncompliance with attention to educational programs and other strategies to improve practice. Table 1 (abstract P71) S28 P76 Intellivue patient monitoring. Data were collected to compare the use of bedside monitor displays with and without horizon screen trends in the care of patients with sepsis. Group 1 (n = 37) completed the sepsis scenario using a standard screen display, and group 2 (n = 38) had the addition of horizon trends on the display. Results The point that marked the onset of sepsis was when each of the physiologic parameters met the current evidence-based screening criteria (HR > 90, RR > 20, MAP < 65, temperature >38°C). Results of this study found statistically significant differences between the standard screen and horizons screen participant groups in the speed in which clinicians were able to reach each measured outcome. This was true in each of the five outcome measurements: onset of sepsis (P < 0.001), initiation of fluid bolus (P < 0.001), initiation of vasopressor (P < 0.001), blood culture order (P = 0.012), and antibiotic administration (P = 0.020). Conclusions These results support the hypothesis that monitoring using horizons trending does indeed contribute to faster clinical decision-making in the simulated septic patient experience. Future research should concentrate on replicating these results in a real clinical environment. P75 Results The incidence of VAP was reduced in the SDD group, even though it was not statistically significant (26.9% vs 16.3%, P = 0.138). The mortality of VAP and septic shock was reduced respectively from 39.6% to 16.7% (P = 0.312) and from 60% to 37.5% (P = 0.835). During the SDD period, Gram-positive infections increased while Gram-negative infections and Candida infections showed a reduction. The percentage of resistant species showed a reduction from 49.1% to 30.5% in all the categories of pathogens (Table 1). Table 1 (abstract P76) Table 1 (abstract P76) Percentages of pathogens no-SDD no-SDD SDD SDD Infection total resistant total resistant Gram-positive 32.5 31% 41.5 20% (% of all (% of all (% of all (% of all VAP) G+) VAP) G+) Gram-negative 54 69% 50 44% (% of all (% of all (% of all (% of all VAP) G–) VAP) G–) Candida 13.5 12.5% 8.5 0% (% of all (% of all (% of all (% of all VAP) candida) VAP) candida) Methods We performed a telephone survey of all NHS critical care units in the North West of England (n = 31). Each unit was telephoned and the duty consultant was asked a series of questions relating to the type of microbiology input to their critical care unit. Results We achieved a 100% response rate. The study looked at 11 teaching hospitals and 21 district general hospitals represen- ting 12% of UK ICUs: 26 (83%) critical care units had live computerised access to microbiology data, 21 (68%) units had an antibiotic policy in place, and 19 (61%) units had a formal microbiology ward round. With the frequency ranging from once per week (one unit) to 7 days per week (four units), most units with a microbiology ward round had this service Monday–Friday (12 units). When asked to rate the value of this ward round, the mean score was 8.6 out of a possible 10 (range 10–5, mode 9). In those units without a microbiology ward round the desirability of such a service was scored on average at 8.5 out of 10 (range 10–3, mode 9). Conclusions SDD and mupirocin were correlated to a reduced incidence of VAP and mortality and to a reduction of resistant species. Medical microbiology ward rounds in critical care L Wilson, G Dempsey University Hospital Aintree, Liverpool, UK Critical Care 2007, 11(Suppl 2):P75 (doi: 10.1186/cc5235) Background Direct microbiological input to critical care is essential for the management of the septic patient. Early broad- spectrum antimicrobial therapy with appropriate diagnostic studies to ascertain causative organisms is well established; there should be reassessment with the aim of using narrow-spectrum antibiotics to prevent the development of antimicrobial resistance, to reduce toxicity and to reduce costs [1]. In systematic analysis of ward rounds in ICUs the information most commonly missing from a patient’s file concerned microbiology findings [2]. Impact of a selective digestive decontamination and nasal mupirocin on the incidence of ventilatory-associated pneumonia and the emergence of bacterial resistance Impact of a selective digestive decontamination and nasal mupirocin on the incidence of ventilatory-associated pneumonia and the emergence of bacterial resistance E De Blasio, A Racca, C Pellegrini, C Di Maria, L Giunta, C Lallo, E Bizzarro, G Prizio, A Capasso Hospital ‘G. Rummo’, Benevento, Italy Critical Care 2007, 11(Suppl 2):P76 (doi: 10.1186/cc5236) E De Blasio, A Racca, C Pellegrini, C Di Maria, L Giunta, C Lallo, E Bizzarro, G Prizio, A Capasso Hospital ‘G. Rummo’, Benevento, Italy Critical Care 2007, 11(Suppl 2):P76 (doi: 10.1186/cc5236) Introduction Selective digestive decontamination (SDD) can reduce the incidence of ventilatory-associated pneumonia (VAP). Some concerns have been raised about the risk of selection of resistant bacteria. We evaluated the impact of a SDD regimen on the incidence of VAP and the development of resistant pathogens. Introduction Selective digestive decontamination (SDD) can reduce the incidence of ventilatory-associated pneumonia (VAP). Some concerns have been raised about the risk of selection of resistant bacteria. We evaluated the impact of a SDD regimen on the incidence of VAP and the development of resistant pathogens. Methods In a polyvalent eight-bed ICU, a retrospective analysis was performed of two periods of 8 months before (no-SDD, 178 patients, mean SAPS II 44.8) and after (SDD, 110 patients, mean SAPS II 48.9) the use of SDD with amphotericin, tobramycin and colistin for oropharyngeal and gastric decontamination and mupirocin for nasal decontamination. The results were analyzed with the chi-square test. P73 The outcome of sepsis and septic shock presenting to the Emergency Department in Australia and New Zealand Methods Simulation research participants (n = 75) were first required to attend a didactic training session focusing on recognition and evidence-based treatment for critically ill patients with sepsis. Participants were then directed to apply these treatments in a simulated sepsis experience. Data were collected at two sites (AACN National Teaching Institute Critical Care Nursing Conference, New Orleans, May 2005 and Long Beach Memorial Medical Center’s Health Skills Education Center). A METI HPS (human patient simulator) was connected to a Philips Medical Systems Intellivue MP 70 in a simulated critical care environment. Participants were given the patient history, and completed the rest of their assessment using the HPS and S Peake for the ARISE Investigators, J Moran for the ANZICS APD Management Committee The Queen Elizabeth Hospital, Adelaide, Australia Critical Care 2007, 11(Suppl 2):P73 (doi: 10.1186/cc5233) S Peake for the ARISE Investigators, J Moran for the ANZICS APD Management Committee The Queen Elizabeth Hospital, Adelaide, Australia Critical Care 2007, 11(Suppl 2):P73 (doi: 10.1186/cc5233) Introduction The outcome of sepsis and septic shock patients admitted to the ICU from the Emergency Department (ED) in Australia and New Zealand was investigated using prospectively collected data from the Australian and New Zealand Intensive Care Society Adult Patient Database. Introduction The outcome of sepsis and septic shock patients admitted to the ICU from the Emergency Department (ED) in Australia and New Zealand was investigated using prospectively collected data from the Australian and New Zealand Intensive Care Society Adult Patient Database. S29 P76 P77 Comparison of bloodstream infections in intensive care unit patients, due to different Gram-negative bacteria 1. Widmer AF: Intensive Care Med 1994, 20 (Suppl 4): S7–S11. Available online http://ccforum.com/supplements/11/S2 assess which of them is associated with higher mortality in ICU patients. CR-BSI was used. Data were compared with historical controls at the same ICU. Also, independent observers evaluated the procedure for technique break (omitting any conditions listed under MBP). Subsequently, in addition to MBP, all central venous catheters were placed under intensivist supervision. Data analysis included one-tailed z tests for proportions and t tests. Patients and methods This study was conducted in the 28-bed multidisciplinary ICU of Evangelismos Hospital in Athens, during an 18-month period (August 2004–January 2006). All ICU patients with blood cultures due to A. baumannii or P. aeruginosa or K. pneumoniae bacteremia, obtained >48 hours after ICU admission, were studied. Patients with BSIs due to more than one of those three pathogens were excluded. Information included patients’ age, gender, underlying disease, admission category, hospitalization before ICU admission, length of ICU stay, source of BSIs and ICU mortality were compared. The illness severity was assessed by APACHE II score on admission and on the day of BSI was calculated prospectively for all patients. Results From 1 January 2000 to 31 December 2002 (control period) the CR-BSI incidence was 12.1/1,000 catheter-days. Following implementation of MBP (1 January 2003–31 October 2004) the CR-BSI incidence decreased to 3.5/1,000 catheter- days (19/5,499 catheter-days), P < 0.02; in 85 independently observed line placements using MBP, 7/85 patients had CR-BSI (8.2%). Technique breaks occurred in 34/85 procedures and were associated with six CR-BSI (17.6%); the 51/85 procedures without technique breaks had one infection (1.9%), P < 0.01. Intensivist supervision (11 January 2004 to 30 April 2006), in addition to MBP, further reduced the incidence to 1.5/1,000 catheter-days (7/4,667 catheter-days), P < 0.04. Results During the study period, among 855 consecutively admitted patients, with ICU stay longer than 48 hours, 197 patients developed BSIs due to A. baumannii (96 patients, incidence 11.23%), P. aeruginosa (44 patients, incidence 5.15%) and K. pneumoniae (57 patients, incidence 6.67%). Of these patients, 85 developed BSIs with two or more pathogens and were excluded. Thus, finally, 64 patients with A. baumannii BSI, 23 with P. aeruginosa, and 25 with K. pneumoniae were compared. Hospitalization before ICU was shorter for K. pneumoniae bacteremic patients compared with those with A. baumannii (1 vs 3 days, P = 0.028) and with those with P. aeruginosa (1 vs 6 days, P = 0.005). On ICU admission, patients with A. P79 Risk of catheter-related bloodstream infection: higher in more severe patients? N Cortez-Dias, A Pais de Lacerda, Z Costa e Silva, C França Hospital de Santa Maria, Lisboa, Portugal Critical Care 2007, 11(Suppl 2):P79 (doi: 10.1186/cc5239) Risk of catheter-related bloodstream infection: higher in more severe patients? Risk of catheter-related bloodstream infection: higher in more severe patients? N Cortez-Dias, A Pais de Lacerda, Z Costa e Silva, C França Hospital de Santa Maria, Lisboa, Portugal Critical Care 2007, 11(Suppl 2):P79 (doi: 10.1186/cc5239) Introduction Vascular devices are associated with the risk of catheter-related bloodstream infection (Cr-BSI). The aim of this study was to evaluate the risk of Cr-BSI in our ICU. Methods A nonconcurrent cohort study at an adult, 11-bed medical/surgical unit, between 1 January and 31 December 2005. Data were retrospectively reviewed from clinical records and bacteriological data concerning the presence of central venous (CVC) or haemodialysis catheter (HDC) colonization and Cr-BSI (no data on arterial catheters) were collected. Catheter insertion and dressing of the insertion site were done according to CDC guidelines for Cr-BSI prevention. Diagnosis of Cr-BSI required microbial concordance between a culture of the removed catheter and a separate percutaneously drawn blood culture, and the exclusion of other overt source of bacteraemia. Intravascular devices were cultured for evidence of colonization whenever there was clinical suspicion of Cr-BSI. Severity scores (SOFA, SAPS II) were assessed and analysed facing Cr-BSI data. Conclusion In ICU patients, the development of BSI due to A. baumannii is associated with a higher severity of illness on admission compared with those due to P. aeruginosa and K. pneumoniae. However, P. aeruginosa BSI is associated with the higher mortality. P78 y g Results During the study period, 378 patients were admitted to the ICU (59% male; mean age 58.3 ± 19.8 years), the mean SOFA score (admission) being 7.9 ± 4.0 and the mean SAPS II (at 24 hours) being 47.6 ± 19.7. In the 266 patients with CVC, the total duration of implantation was 3.190 days, with a mean duration of CVC placement/patient of 12 days. Positive cultures of CVC were found in 18 patients (6.8%). The incidence density of positive catheter cultures was 6.3/1,000 days of CVC use. CVC-related BSI was diagnosed in 5 patients, the risk of CVC-related BSI being 1.6/1,000 days of CVC use. Fifty-two patients also had a HDC. Positive cultures of HDC occurred in two of these patients (3.8%), none of them with Cr-BSI. The isolated microorganisms from CVC and HDC were typical skin bacteria, excluding two cases with catheter colonization in patients with other overt sources of bacteraemia. The mean SOFA score in patients with positive catheter cultures was 10.2 ± 3.1, the mean SAPS II was 63 ± 19.6 and the mean catheter placement duration in these patients was 32.1 ± 15.7 days. The overall ICU mortality rate was Maximal barrier precautions, intensivist supervision, and catheter-related bloodstream infections Available online http://ccforum.com/supplements/11/S2 baumannii had a higher APACHE II score compared with those with K. pneumoniae (19.53 ± 7.6 vs 15.0 ± 5.4, respectively, P = 0.017) and lower hematocrit and hemoglobin values (29.8 ± 6.5 vs 35.4 ± 6.5, P = 0.002 and 9.9 ± 2.2 vs 11.9 ± 2.2, P = 0.001) respectively. Also on BSI day, hematocrit was lower in patients with A. baumannii and with P. aeruginosa bacteremia, compared with those with K. pneumoniae bacteremia (26.6 ± 4.5 vs 29.6 ± 4.5, P = 0.016 and 26.1 ± 3.8 vs 29.6 ± 4.5, P = 0.021). The respiratory tract was the most common source of BSIs due to A. baumannii compared with P. aeruginosa and K. pneumoniae (56.3% vs 26.1%, P = 0.013 and 56.3% vs 12.0%, P = 0.001). Mortality was higher in the presence of P. aeruginosa and A. baumannii BSIs, compared with K. pneumoniae (56.5% vs 24.0%, P = 0.021 and 48.4% vs 24.0%, P = 0.036, respectively). Conclusion While MBP can reduce the incidence of CR-BSI, placement of central venous catheters by residents under intensivist supervision can further lower the incidence. Comparison of bloodstream infections in intensive care unit patients, due to different Gram-negative bacteria Comparison of bloodstream infections in intensive care unit patients, due to different Gram-negative bacteria Conclusion Direct microbiological advice at the bedside is highly valued by ICU consultants. Antibiotic prescribing is generally well controlled, with two-thirds of units having an agreed antibiotic policy in place. Work will continue to determine whether these results reflect the national picture in the United Kingdom. References Conclusion Direct microbiological advice at the bedside is highly valued by ICU consultants. Antibiotic prescribing is generally well controlled, with two-thirds of units having an agreed antibiotic policy in place. Work will continue to determine whether these results reflect the national picture in the United Kingdom. M Pratikaki, E Platsouka, C Sotiropoulou, K Kritikos, M Agrafiotis, S Kolias, S Nanas, O Paniara, C Roussos, C Routsi Evangelismos, Athens, Greece Critical Care 2007, 11(Suppl 2):P77 (doi: 10.1186/cc5237) Introduction To compare the incidence and risk factors of bloodstream infections (BSIs) due to Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae and to 1. Widmer AF: Intensive Care Med 1994, 20 (Suppl 4): S7–S11. F i d W J Cli M i S30 2. Friesdorf W: J Clin Monit 1994, 10:201-209. Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 P80 Background Nosocomial catheter-related bloodstream infections (CR-BSI) have been associated with increased morbidity and possibly increased mortality in critically ill patients. Central venous catheters impregnated with rifampin and minocycline (RM) have been shown to decrease rates of colonization and CR-BSI when compared with controls and with the chlorhexidine/silver sulfadiazine catheter. However, recent randomized trials challenged the clinical impact of such catheters, showing decreased rates in colonization but not in CR-BSI. We designed this pilot trial to compare the rates of colonization and CR-BSI in RM catheters and controls in a Brazilian population of critically ill patients. P80 Tunnelled central venous catheter-related infection in cardiothoracic critical care J Mitchell, P Shetty, F Cox, P Vuddamalay Royal Brompton & Harefield NHS Trust, Harefield, UK Critical Care 2007, 11(Suppl 2):P80 (doi: 10.1186/cc5240) Introduction Tunnelled central venous cannulae (CVC) are used in cardiothoracic (CT) critical care for long-term inotrope, antibiotic and renal replacement therapy (RRT). The incidence of blood- stream-related infection (BSI) related to all types of CVC is between 2.9 and 11.3 per 1,000 catheter-days [1]. In CT or cardiology practice the incidence for all CVC-related infection is 2.9–4.5 per 1,000 catheter-days. The incidence of BSI is reduced using tunnelled CVC, although there are little published data on the incidence of BSI in tunnelled CVC in CT critical care. CVC- related infection has been recognised as a priority in the UK initiative ‘Saving Lives’ [2]. We reviewed tunnelled CVC-related infection in a tertiary UK CT centre with a significant transplant population. Methods A prospective, nonrandomized, controlled clinical trial was conducted in one medico-surgical 19-bed ICU. Adult patients needing a double or triple central venous catheter were sequentially assigned in permuted blocks of five to undergo insertion of a control or RM-impregnated catheter. After removal, all tips were cultured by the roll-plate method in association with one or two peripheral blood cultures. Rates of colonization and CR-BSI were recorded and compared. Results Of 120 catheters inserted, 100 could be evaluated for colonization and CR-BSI. Forty-nine in the uncoated group and 51 in the coated group. Clinical characteristics of patients and risk for infection were similar in the two groups, use of propofol was more frequent in the uncoated group and the presence of a vascular device, other than the study catheter, was more frequent in the antibiotic-coated group. P81 20.1%, being 40% in the subgroup of patients in whom Cr-BSI was diagnosed. ANCCADI – Antibiotic Coated Catheter to Decrease Infection: a pilot trial Conclusions Preventing Cr-BSI is important, but special care is particularly relevant in patients with higher SAPS II scores and a longer duration of catheter placement. More studies are needed to confirm this possible higher risk of Cr-BSI in this more severe patient subgroup. P Kurtz, M Kalichsztein, G Nobre, G Almeida, J Kezen, F Braga, P Rosa, G Penna, L Drumond, R Vegni, M Freitas, M Pinto Casa de Saude Sao Jose, Rio de Janeiro, Brazil Critical Care 2007, 11(Suppl 2):P81 (doi: 10.1186/cc5241) Maximal barrier precautions, intensivist supervision, and catheter-related bloodstream infections Maximal barrier precautions, intensivist supervision, and catheter-related bloodstream infections T Papadimos, S Hensley, J Hofmann, A Casabianca, M Borst, J Fath, J Duggan University of Toledo College of Medicine, Toledo, OH, USA Critical Care 2007, 11(Suppl 2):P78 (doi: 10.1186/cc5238) Introduction Catheter-related bloodstream infections (CR-BSI) have significant costs. Use of maximal barrier precautions (MBP) may reduce the incidence of CR-BSI. We studied MBP with/ without intensivist supervision of residents on CR-BSI incidence. Methods We prospectively studied CR-BSI incidence in an ICU following the implementation of MBP (hand washing before line placement, sterile site preparation, draping the entire patient in sterile fashion, use of hat, mask, gloves and gown, maintenance of a sterile field, assistants following the same precautions, and sterile dressing application). The Centers for Disease Control definition of S31 P81 20.1%, being 40% in the subgroup of patients in whom Cr-BSI was diagnosed. Conclusions Preventing Cr-BSI is important, but special care is particularly relevant in patients with higher SAPS II scores and a longer duration of catheter placement. More studies are needed to confirm this possible higher risk of Cr-BSI in this more severe patient subgroup. P80 Three RM-coated catheters (5.9%) were colonized compared with nine (18.4%) control catheters (relative risk, 0,28; 95% confidence interval, 0.07–1.096; P = 0.05). Three cases of CR-BSI (5.9%) occurred in patients who received RM catheters compared with five in the control group (10.2%). There was no significant differences in the incidence of CR-BSI between RM-coated and uncoated catheters. Uncoated catheters were more frequently colonized but this difference just failed to show statistical significance. When the duration of catheter placement were taken into consideration, Kaplan–Meier analysis showed no significant differences in the risk of colonization or CR-BSI between RM-coated and uncoated catheters. Rates of CR-BSI were seven per 1,000 catheter-days in the RM-coated group compared with 11.4 per 1,000 catheter-days in the uncoated group (P = 0.7). Gram-positive and Gram-negative organisms were similarly responsible for colonizing catheters in our study; there was no difference in rates of colonization by Candida species. Conclusion In this pilot study, we showed a trend toward lower rates of colonization in RM-coated catheters when compared with uncoated control catheters. The incidence and rates of CR-BSI were similar in the two groups, probably because of a small number of catheters studied. Development of a prospective randomized trial with a larger number of patients is underway to confirm or refute these results. Methods A retrospective analysis from November 2001 to 2006 of culture and sensitivity results of tunnelled CVC tips (Bard Groshong® cuffed catheter and HemoGlide®) and blood cultures from the same patients. Results Ninety-three CT critical care patients received a tunnelled subclavian CVC. The indications were inotropes (n = 40 (43%)), antibiotic administration (n = 27 (29%)), RRT (n = 14 (15.1%)) and unknown (n = 10 (10.8%)). The mean duration of the catheter remaining in situ was 36 days (SD 44.0, range 1–164). Culture results are presented in Table 1. Twelve patients had an established CVC-related BSI. The mean infection rate/1,000 catheter-days was 3.6. Table 1 (abstract P80) Positive CVC Positive Positive tip culture blood culture from both Positive culture results (%) 36.6 18.3 12.9 Mean infection rate/ 10.2 5.1 3.6 1,000 catheter-days Conclusion In this pilot study, we showed a trend toward lower rates of colonization in RM-coated catheters when compared with uncoated control catheters. The incidence and rates of CR-BSI were similar in the two groups, probably because of a small number of catheters studied. J Moon J Moon Chonnam National University Hospital, Gwang-ju, Republic of Korea Critical Care 2007, 11(Suppl 2):P82 (doi: 10.1186/cc5242) Introduction Blood culture was commonly performed, without any specific indication, at the Emergency Department. However, the true positive rate was found to be very low (1.8–5%) and patients with true bacteremia usually had such risk factors as an indwelling catheter, severe underlying disease or an immunocompromised state. This study was performed to determine the usefulness of performing blood culture for managing febrile immunocompetent patients who present to the Emergency Department. Method We prospectively analyzed the medical characteristic and the results of blood culture of febrile immunocompetent patients who were more than 18 years old and who presented to the Chonnam National University Hospital Emergency Center from April 2005 to October 2005. Fever was defined as a single axillary temperature higher than 38.0°C. The two sets of blood for culture were drawn at the antecubital area by the emergency physician who knew well how to obtain blood for culture. The bacteremia was classified as true bacteremia or contamination, based on the presence of clinical signs and symptoms and also on the criteria of MacGregor. For the true bacteremia group, we further investigated the changes that occurred with the previously administered antibiotic therapy according to the results of blood culture. facility, over a period from February to June 2006. SIRS was defined according to the criteria proscribed by the Society of Critical Care Medicine. A research officer stationed in the ER identified patients. Exclusion criteria were age < 18 years, patients transferred from other hospitals or chronic care facilities. Demo- graphic and study-specific data were collected. The patient was followed until subsequent death or discharge. The primary outcome variable was survival to hospital discharge and the secondary outcome was length of hospitalization. An independent t-test analysis was carried out for the primary independent variable (timing of administration of antibiotics) and primary outcome (mortality) for significant differences between the groups. A two- sided P value <0.05 was considered as statistical significance. Logistic regression modeling was used to examine survival as a function of timing of antibiotic administration. Results This study included 182 patients: of the 182 cultures, only 36 were positive with 10 contaminants (5.5%) and 26 true positives (14.3%). P84 Introduction Despite improvements in technology and healthcare services, mortality rates from severe sepsis have remained unchanged over the past few decades. Exciting new data are emerging about the benefits of early, aggressive management in the Emergency Room (ER). We carried out this study to study the patterns of antibiotic administration in our ER and their effects on the length of hospitalization and survival. P83 Impact of early antibiotics on severe sepsis – are we doing a good job? N Salahuddin, S Siddiqui, J Razzak, A Raza Aga Khan University & Hospital, Karachi, Pakistan Critical Care 2007, 11(Suppl 2):P83 (doi: 10.1186/cc5243) J Moon The most common disease that required blood culture in the Emergency Department was respiratory infection (57/182) and the most common disease with true bacteremia was urinary infection (41.9%). A low initial level of albumin was the characteristic associated with a positive blood culture result on multivariate analysis. Management of only five patients was influenced by the blood culture results (2.7%). Results Patients enrolled in the study numbered 111. At presen- tation 36 patients (32.4%) had 1/4 criteria for SIRS, 67 (60.4%) had 2/4 criteria and only eight (7.2%) patients had 3/4 criteria. Sixteen patients (14.4%) were in shock. Sepsis was confirmed by cultures in 96 (86.5%) patients. One hundred (90.1%) patients received intravenous antibiotics in the ER; the average time from triage to actual administration was 2.8 (± 1.86) hours. The timing of administration of antibiotics was statistically significant in determining survival. Patients with sepsis and receiving antibiotics in <1 hour had a mean survival of 99% and a length of hospitalization of 3 days as compared with those receiving anti- biotics in 1–4 hours (84.5% survival, LOS 5.25 days) and patients who received antibiotics in >4 hours (76% survival, LOS 7 days, P < 0.003). Using a Cox regression model, we were able to demonstrate that survival dropped acutely with an hourly delay in antibiotic administration. Overall mortality with sepsis was 34.2%. Conclusions Administration of appropriate antibiotics within 4 hours of arrival in the ER has a significantly favorable impact on survival in patients with sepsis. Conclusion The blood cultures, as were usually ordered for febrile immunocompetent patients in the Emergency Department, rarely altered patient management and the results had limited usefulness. The emergency physician who initially treats these patients has to consider this limitation of blood culture. Also, eliminating blood cultures for immunocompetent patients may hold down unneces- sary medical expenses. Is the blood culture useful in febrile immunocompetent patients in the Emergency Department? Is the blood culture useful in febrile immunocompetent patients in the Emergency Department? P80 Development of a prospective randomized trial with a larger number of patients is underway to confirm or refute these results. Conclusion The incidence of tunnelled CVC colonisation and positive blood cultures in this group of CT critical care patients is in line with previously published data for all types of CVC. Coagulase-negative staphylococcus was the predominant isolate in both this audit and previously published data [1]. References 1. O’Grady NP, Alexander M, Dellinger EP, et al: Guidelines for the prevention of intravascular catheter-related infections. Centers for Disease Control and Prevention, Atlanta, USA. MMWR 2002, 51(RR-10):1-29. 2. Saving Lives: The Delivery Programme to Reduce Healthcare Associated Infections (HCAI) including MRSA. London: Department of Health; 2005. S32 Available online http://ccforum.com/supplements/11/S2 Figure 1 (abstract P83) P82 Figure 1 (abstract P83) Timing of admissions and outcome of pneumonia in intensive care units in the United Kingdom H Boralessa1, C Welch2, K Raveendran1, E Veerasingam1, N Ibrahim1, D Harrison2 1Oldchurch Hospital, Essex, UK; 2ICNARC, London, UK Critical Care 2007, 11(Suppl 2):P86 (doi: 10.1186/cc5246) Table 1 (abstract P85) Results A total of 101 patients were enrolled, 61 patients during period A and 40 patients during period B. No significant differences were found between mean age (48.6 years vs 50.4 years old), SAP II score (44.5 vs 46.5), aetiology of coma (mainly ischaemic stroke, cardiac arrest, refractory epilepsy, intoxication), and early-onset (n = 12 vs n = 6) or late-onset pneumonia (n = 1 vs n = 2). During period B, the time for onset of colonisation (6.6 days vs 3 days, P = 0.008) or pneumonia (8.4 days vs 4.2 days, P = 0.03) was increased compared with period A. We did not diagnose multidrug-resistant infection or colonisation. No difference was found with regard to mortality and morbidity: duration of mechanical ventilation (5.7 days vs 6.7 days) or total hospitalisation stay (26.6 days vs 16.9 days), total mortality (n = 9 vs n = 10 patients) or at day 28 (n = 6 vs n = 7 patients), respectively, in periods A and B. In multivariate analysis, tobacco, cardiac arrest and ischaemic stroke were independent risk factors of pneumonia. Appropriateness of antibiotic therapy Conclusion There are significant differences in antibiotic prescribing practices when public and private sectors are compared. Appropriate early antibiotic prescriptions reduce mortality. Attention to education and systems that address prescribing practices is indicated. Conclusion In our study, contrary to previous ones [1,2], anti- bioprophylaxy did not show a decrease in the incidence of nosocomial pneumonia in medical comatose patients with Glasgow Coma Score < 8 under mechanical ventilation. On the other hand, antibiotics induce a later onset of colonisation and lung infections. Despite a prevention of early-onset nosocomial pneumonia, our data do not support the use of regular prophylactic antibiotics. References 1. Sirvent JM, et al.: Protective effect of intravenously admin- istered cefuroxime against nosocomial pneumonia in patients with structural coma. Am J Respir Crit Care Med 1997, 155:1729-1734. Introduction This study aims to assess the association between the timing of admission and outcome in patients admitted with pneumonia to ICUs in the United Kingdom. 2. Acquarolo A, et al.: Antibiotic prophylaxis of early onset pneumonia in critically ill comatose patients. A random- ized study. Intensive Care Med 2005, 31:510-516. Methods All patients admitted to an ICU with a primary reason for admission of pneumonia were extracted from the Case Mix Programme Database. ‘Early’ admissions, admitted to the ICU on the day of admission to hospital (12,475), were compared with ‘late’ admissions, admitted to the ICU on a later date (21,948). The ICU and hospital mortality, number of organs failed, renal dysfunction, and length of stay in hospital were compared between the two groups. An association was sought between timing of admission and mortality. Patients were stratified by CURB 65 score on admission to the ICU. Mortality was compared between the two groups. Odds ratios were used to analyse data. P < 0.05 was considered significant. Protective effect of antibiotic prophylaxis against early- onset nosocomial pneumonia in comatose patients J Navellou, C Manzon, M Puyraveau, D Perez, E Laurent, C Patry, G Capellier CHU Jean Minjoz, Besancon, France Critical Care 2007, 11(Suppl 2):P84 (doi: 10.1186/cc5244) J Navellou, C Manzon, M Puyraveau, D Perez, E Laurent, C Patry, G Capellier CHU Jean Minjoz, Besancon, France Critical Care 2007, 11(Suppl 2):P84 (doi: 10.1186/cc5244) Methods This was a prospective, observational cohort study that reviewed all adult patients presenting with systemic inflammatory response syndrome (SIRS) to the ER of the Aga Khan University Hospital, which is a 554-bed primary care/tertiary care referral Objective To study the impact of prophylactic antibiotics on the occurrence of early-onset nosocomial pneumonia in patients with medical coma. S33 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin postculture modification of therapy, duration of therapy and, finally, impact of appropriate antibiotic choice on mortality. Results See Table 1. Public-sector practice is better with respect to pretherapy sampling and duration of treatment. Better modification of treatment occurs in the private sector. Overall mortality of both groups was 10/82 (12%) when antibiotic choice was appropriate compared with 28/90 (31%) (P < 0.05) when therapy was inappropriate. postculture modification of therapy, duration of therapy and, finally, impact of appropriate antibiotic choice on mortality. Patients and methods An open, before and after, single-center trial, in the medical ICU of the University Hospital of Besancon, France. A first period (A, retrospective) extended during 18 months (April 2003–October 2004) without antibiotic prophylaxis and was followed by a second period (B, prospective) during 18 months (November 2004–April 2006). Patients received prophylaxis treatment by amoxicillin and clavulanic acid, shortly after intubation and during a 24-hour period. Inclusion criteria were medical loss of consciousness, Glasgow Coma Score < 8, and length of intubation > 48 hours. Results See Table 1. Public-sector practice is better with respect to pretherapy sampling and duration of treatment. Better modification of treatment occurs in the private sector. p Overall mortality of both groups was 10/82 (12%) when antibiotic choice was appropriate compared with 28/90 (31%) (P < 0.05) when therapy was inappropriate. Table 1 (abstract P85) Table 1 (abstract P85) Appropriateness of antibiotic therapy Intervention Sector Number Percentage Preculture sampling Private 27/62 43* Public 73/120 61 Modification of antibiotics Private 49/61 80 Public 18/27 67 Duration of treatment Private 25/134 19* Public 26/49 53 *P < 0.05. Table 1 (abstract P85) P88 Introduction The medical literature shows that the most important prognosis factor in nosocomial pneumonia is the correct empirical antimicrobial therapy. Recently the microorganisms have been becoming more resistant to the usual antibiotics and there are many reports of Gram-negative bacilli (GNB) only susceptible to Polimixyn b (PB). The ATS guideline does not suggest the use of PB as an empirical therapy, while the Brazilian Sepsis Guideline (BG) allows the use of this antibiotic in special circumstances. The aim of this study was to compare the efficacy of both guidelines, based on the microbiological data. Results In our 22-bed ICU, during a 27-month period, 156 patients underwent BAL procedures due to clinical suspicion of VAP. Out of these, 118 patients (120 BAL) had semiquantitative tracheal aspirate (SQTA) performed 48 hours prior to the clinical diagnosis of VAP (males 71/118; mean age 47 ± 16 years; SAPS II 35 ± 10). See Table 1 for pathogen prediction by SQTA surveil- lance cultures. See Table 2 for concordance of SQTA–BAL when only multiresistant microorganisms are considered. Negative BAL Methods This is a retrospective study with 93 cases of nosocomial pneumonia diagnosed according to the ATS criteria, managed in our ICU from 1 February 2005 to 16 September 2006. We analyzed the efficacy of both guidelines, using them during all the study period or stratifying the patients into two groups according to the research median period (24 November 2005). Table 1 (abstract P87) Concordance, a) Same microorganisms SQTA–BAL 66/76 (87%) 76/120 (63%) b) No significant growth 10/76 (13%) Partial a) 2 microorganisms SQTA–1 BAL 4/17 (24%) concordance, b) 1 microorganism SQTA–1 BAL 13/17 (76%) 17/120 (14%) No concordance, a) No significant growth 14/127 27/120 (23%) SQTA–1 or 2 microorganisms BAL b) Different microorganisms SQTA–1 BAL 13/27 Table 2 (abstract P87) Multiresistant microorganism SQTA BAL Concordant % Ps. Reference 1. James L, Hoppe-Bauer JE: Processing and interpretation of lower resp tract in specimens. In Clinical Microbiology Pro- cedures Handbook. Edited by Isenberg HD. Washington, DC: ASM Press; 1992:1.15.1–1.15.8. 1. James L, Hoppe-Bauer JE: Processing and interpretation of lower resp tract in specimens. In Clinical Microbiology Pro- cedures Handbook. Edited by Isenberg HD. Washington, DC: ASM Press; 1992:1.15.1–1.15.8. H Bagnulo, M Godino, A Galiana, M Bertulo, W Pedreira Hospital Maciel, Montevideo, Uruguay Critical Care 2007, 11(Suppl 2):P87 (doi: 10.1186/cc5247) Introduction Most investigators discuss the predictive value of respiratory surveillance cultures in mechanically ventilated patients and doubt on the appropriate selection of the antibiotic therapy based on these findings, when pneumonia develops. The aim of our study was to evaluate whether microorganisms cultured from semiquantitative tracheal aspirates (SQTA) in the 48 hours prior to the clinical suspicion of ventilator-associated pneumonia (VAP) were predictive of the etiology, compared with the bronchoalveolar lavage (BAL) results performed on the same day that the clinical diagnosis was considered Antibiotic prescribing practices in public and private-sector intensive care units in South Africa S Bhagwanjee, H Perrie, J Scribante, F Paruk University of the Witwatersrand and the CCSSA, Johannesburg, South Africa Critical Care 2007, 11(Suppl 2):P85 (doi: 10.1186/cc5245) Results There were small but statistically significant differences between the two groups in mean age, APACHE II score, CURB 65 score and number of organ failures, and the presence of Introduction Considerable variability exists in antibiotic prescribing Introduction Considerable variability exists in antibiotic prescribing practices. A dichotomous health care system in South Africa has created the opportunity for vastly differing practices. As part of a national 1-day sepsis prevalence study (PISA), a review was undertaken of antibiotic prescribing practices in public and private- sector ICUs. Table 1 (abstract P86) CURB65 Odds ratio 95% CI P value 1 1.02 0.9–1.16 0.8 2 1.23 1.13–1.34 <0.0001 3 1.25 1.16–1.35 <0.0001 4 1.46 1.29–1.65 <0.0001 5 1.41 1.03–1.91 0.03 Method Following appropriate institutional approval, 43 ICUs were selected using the proportional probability sampling technique. This was applied to a national database of ICUs. Every seventh bed was selected from all the serially placed units. Antibiotic therapy was reviewed by two independent reviewers. Data collected included the appropriateness of pretherapy cultures, S34 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 cultures with SQTA growth were never found. Polymicrobial SQTA cultures: 13 concordant, seven only partial concordant, four not concordant. There was no incidence in our results related to previous antibiotic therapy: 33% of the concordant, 24% of the partial concordant and 29% of the no concordant were on antibiotics when SQTA was obtained. respiratory organ failure. There was no difference in the presence of renal dysfunction. Late admissions with pneumonia had higher ICU and hospital mortality, and longer hospital stay. At each CURB 65 score the late admissions had higher hospital mortality, which was significant at scores of 2–5 (Table 1). Conclusion Early admission may reduce mortality in patients admitted to ICUs with pneumonia. CURB 65 scores could facilitate triage of patients with pneumonia. Conclusions In our patient population, routine surveillance SQTA cultures accurately predict more than 60% of the etiologic agents of VAP. This prediction increases to 80% when multiresistant microorganisms are considered. Due to routine surveillance cultures, our antibiotic prescriptions can become more adequate. P88 Comparing a Brazilian guideline to treat nosocomial pneumonia with the ATS guideline in a tertiary hospital in Brazil M Kalichsztein, B Wajsbrot, A dos Santos, J Camillo Jorge, B Fabricio, K Pedro, G Nobre, E Moreira, M Freitas, A Paula Casa de Saúde São José, Rio de Janeiro, Brazil Critical Care 2007, 11(Suppl 2):P88 (doi: 10.1186/cc5248) Comparing a Brazilian guideline to treat nosocomial pneumonia with the ATS guideline in a tertiary hospital in Brazil M Kalichsztein, B Wajsbrot, A dos Santos, J Camillo Jorge, B Fabricio, K Pedro, G Nobre, E Moreira, M Freitas, A Paula Casa de Saúde São José, Rio de Janeiro, Brazil Critical Care 2007, 11(Suppl 2):P88 (doi: 10.1186/cc5248) Methods Routine SQTA were performed twice weekly in all intubated patients for over 72 hours according to the methodology described elsewhere [1]. Fiberoptic bronchoscopy with BAL was preformed the same day that VAP was suspected according to Johanson criteria (fever, leucocytosis, purulent secretions and infiltrate on radiograph) plus gas-exchange deterioration. Results In our 22-bed ICU, during a 27-month period, 156 patients underwent BAL procedures due to clinical suspicion of VAP. Out of these, 118 patients (120 BAL) had semiquantitative tracheal aspirate (SQTA) performed 48 hours prior to the clinical diagnosis of VAP (males 71/118; mean age 47 ± 16 years; SAPS II 35 ± 10). See Table 1 for pathogen prediction by SQTA surveil- lance cultures. See Table 2 for concordance of SQTA–BAL when only multiresistant microorganisms are considered. Negative BAL Methods Routine SQTA were performed twice weekly in all intubated patients for over 72 hours according to the methodology described elsewhere [1]. Fiberoptic bronchoscopy with BAL was preformed the same day that VAP was suspected according to Johanson criteria (fever, leucocytosis, purulent secretions and infiltrate on radiograph) plus gas-exchange deterioration. Introduction The medical literature shows that the most important prognosis factor in nosocomial pneumonia is the correct empirical antimicrobial therapy. Recently the microorganisms have been becoming more resistant to the usual antibiotics and there are many reports of Gram-negative bacilli (GNB) only susceptible to Polimixyn b (PB). The ATS guideline does not suggest the use of PB as an empirical therapy, while the Brazilian Sepsis Guideline (BG) allows the use of this antibiotic in special circumstances. The aim of this study was to compare the efficacy of both guidelines, based on the microbiological data. Are routine endotracheal aspirates predictive of the etiology of ventilator-associated pneumonia? Are routine endotracheal aspirates predictive of the etiology of ventilator-associated pneumonia? Are routine endotracheal aspirates predictive of the etiology of ventilator-associated pneumonia? P89 the correlation between bronchoalveolar bacterial burden and the lung inflammatory response. Outcomes from ventilator-associated pneumonia caused by multidrug-resistant organisms or Pseudomonas: results from 28 intensive care units Objective The aim of the present study was to evaluate the relationship between bronchoalveolar cytokine expression and bacterial burden in mechanically ventilated patients with suspected pneumonia. Methods Mechanically ventilated patients with suspected pneumonia admitted to the ICU from November 2004 to January 2006 were prospectively enrolled. Fiberoptic bronchoalveolar lavage (BAL) was performed with 150 ml sterile isotonic saline in three aliquots of 50 ml; local anesthetic was not used. BAL samples for microbiologic quantitative cultures and BAL cytokines – IL-6, IL 8, TNFα, granulocyte colony-stimulating factor (G-CSF) and granulocyte–monocyte colony-stimulating factor (GM-CSF) – were measured. Introduction Patients who develop ventilator-associated pneumonia (VAP) caused by either multidrug-resistant organisms (MDRO) or Pseudomonas may have poor clinical outcomes. We sought to further clarify this potential relationship using a database from a large multicenter trial of diagnostic and therapeutic strategies in patients who had suspected VAP. Results Fifty-nine patients were included, and most of the patients (79.7%) had prior antibiotic therapy. Twenty-two patients (37.2%) had a positive bacterial culture defined as a diagnostic threshold >10,000 colony-forming units/ml. Only the concentration of TNFα was significantly higher in the group of patients with positive BAL (Table 1). Methods Patients receiving mechanical ventilation (MV) for ≥96 hours and who developed suspected VAP (new or worsening pulmonary opacities on CXR, and at least two of fever, leukocytosis, change in sputum purulence, increased O2 needs, or isolation of potentially pathogenic bacteria from sputum) were eligible. At enrolment, all patients had cultures obtained from either BAL or endotracheal aspirates. MDRO were defined as those resistant to ≥2 classes of antibiotics. Patients were followed until 28 days after enrolment, death, or hospital discharge. Conclusions (1) There is a significant correlation between TNFα in BAL fluid and the lung bacterial burden. (2) BAL TNFα is an early marker of pneumonia in mechanical ventilated patients despite prior antibiotic therapy. Clinical implication Cytokine measurements in BAL may be a diagnostic tool to support the diagnosis of the initial phase of pneumonia. Results Seven hundred and thirty-nine patients from 28 ICUs in Canada and USA were enrolled. At enrolment, cultures from 10.0% (95% CI 7.9–12.4%) of the patients grew MDRO or Pseudomonas. The prevalence of MDRO at enrolment was 5.2% (3.6–6.8%). P91 P91 Risk factors for treatment failure in patients with ventilator- associated pneumonia receiving appropriate antibiotic therapy G Gursel, M Aydogdu, E Ozyilmaz, T Ozis Gazi University School of Medicine, Ankara, Turkey Critical Care 2007, 11(Suppl 2):P91 (doi: 10.1186/cc5251) Risk factors for treatment failure in patients with ventilator- associated pneumonia receiving appropriate antibiotic therapy Conclusion The isolation of MDRO or Pseudomonas from respiratory tract specimens of patients with suspected VAP is associated with prolonged MV, increased ICU and hospital stay, and increased risk of death. Inadequate initial empiric antibiotic treatment may be a contributing factor. Introduction Treatment failure (TF) can be anticipated in 30–40% of patients developing ventilator-associated pneumonia (VAP). Little information about lack of response of VAP to treatment is available. The aim of the study is to evaluate potential risk factors for TF in patients with VAP receiving appropriate antibiotic therapy. Methods A prospective observational cohort study. Microbio- logically confirmed (>105 colony-forming units/ml) clinical findings (CPIS > 6) were necessary for the diagnosis of VAP. TF was defined as a lack of clinical (in first 3 days of the therapy) and microbiological (in first 7 days of the therapy) response to therapy. All patients had surveillance cultures for endotracheal aspirate (every second day), urine and blood (weekly). Student’s t tests, chi- square tests and logistic regression analyses were used for statistical analyses. P89 There were no differences in APACHE II, MODS, or PaO2/FiO2 at baseline between those whose specimens grew MDRO or Pseudomonas and those whose specimens did not. Patients with MDRO or Pseudomonas had higher 28-day mortality (RR 1.59, 95% CI 1.07–2.37, P = 0.04) and inhospital mortality (RR 1.48, 95% CI 1.05–2.07, P = 0.05) and a trend towards higher ICU mortality (RR 1.42, 95% CI 0.90–2.23, P = 0.14) than those whose specimens did not grow these organisms. Median duration of MV (12.6 vs 8.7 days), ICU length of stay (16.2 vs 12.0 days) and hospital length of stay (55.0 vs 41.8 days) was greater in patients with MDRO or Pseudomonas than in those whose specimens did not grow these pathogens (P = 0.05). Adequacy of initial empiric therapy was 68.5% in patients whose specimens grew MDRO or Pseudomonas compared with 93.9% in those without these organisms (P < 0.001). Table 1 (abstract P90) BAL– BAL + P IL-6 BAL (pg/ml) 180.3 ± 252 293.4 ± 421 0.410 IL-8 BAL (pg/ml) 1,301 ± 1,045 1,681 ± 1,315 0.442 TNF BAL (pg/ml) 48.9 ± 80.7 222.6 ± 308 0.022 G-CSF BAL (pg/ml) 444.8 ± 565 408.1 ± 491 0.713 GM-CSF BAL (pg/ml) 14.1 ± 23.4 9.35 ± 17.32 0.126 P91 P88 aeruginosa 22 22 20/24 83 Acinetobacter 14 11 10/15 67 MRSA 8 9 8/9 89 Klebsiella 2 2 2/2 100 Stenotrophomona 1 1 1/1 100 Total multiresistant 41/51 80 microorganisms Table 1 (abstract P87) Concordance, a) Same microorganisms SQTA–BAL 66/76 (87%) 76/120 (63%) b) No significant growth 10/76 (13%) Partial a) 2 microorganisms SQTA–1 BAL 4/17 (24%) concordance, b) 1 microorganism SQTA–1 BAL 13/17 (76%) 17/120 (14%) No concordance, a) No significant growth 14/127 27/120 (23%) SQTA–1 or 2 microorganisms BAL b) Different microorganisms SQTA–1 BAL 13/27 p Results There were 67 cases of ventilator-associated pneumonia (VAP) and 26 cases of non-VAP. The overall result shows that the ATS would be effective in 76% (CI 67–85%) and the BG in 87.9% (CI 81–94.7%) of the cases. This difference was statistically significant (P = 0.035). The most prevalent bacteria were Acinetobacter sp. and Pseudomonas aeruginosa. From February to August 2005 there were a burden of multiresistant (MR) GNB, only susceptible to PB. Using the ATS or the BG in this period, the guidelines would be effective in 64% (CI 51–77%) and 84.4% (CI 74.8–94%) respectively (P = 0.017). In the second half of the study we controlled the MR GNB, and the efficacy of both guidelines were similar between ATS and BG (97% vs 93.9%; P = 1). Table 2 (abstract P87) Multiresistant microorganism SQTA BAL Concordant % Ps. aeruginosa 22 22 20/24 83 Acinetobacter 14 11 10/15 67 MRSA 8 9 8/9 89 Klebsiella 2 2 2/2 100 Stenotrophomona 1 1 1/1 100 Total multiresistant 41/51 80 microorganisms Table 2 (abstract P87) Conclusions Our data show that the more restrictive ATS guideline can significantly lead to a wrong empirical therapy in MR GNB high-prevalence situations. The use of the BG can lead to a better empirical treatment in this situation. This information enhances the need for ICU flora knowledge, which are seasonal, so there is no ‘all time and place perfect guideline’, although the BG was a better option in our ICU than the ATS guideline. S35 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine P90 Bacterial burden and bronchoalveolar cytokines in mechanically ventilated patients with suspected pneumonia P92 Results We had 40 episodes (2,247 ventilator-days) of VAP (40/133 patients) and 45 isolates. In early-onset pneumonia (≤5 days, eight episodes, three with two isolates): six Acinetobacter baumannii: meropenem, colistin, gentamicin (five); three Pseudo- monas aeruginosa: piperacillin, aztreonam, imipenem, ceftazidime, colistin, ciprofloxacin, cefepime, meropenem, aminoglycosides; one Klebsiella pneumoniae: meropenem, colistin, tetracycline; Fungi 1: no susceptibility results. In late-onset pneumonia (>5 days, 32 episodes, two with two isolates): 25 A. baumannii: four to amoxicillin-clavulanic, ceftazidime, piperacillin-tazobactam, Intensive care nurses’ knowledge of evidence-based guidelines for the prevention of ventilator-associated pneumonia Intensive care nurses’ knowledge of evidence-based guidelines for the prevention of ventilator-associated pneumonia S Labeau1, D Vandijck2, P Van Aken3, B Claes3, S Blot2 1Hogeschool Ghent, Belgium; 2Ghent University Hospital, Ghent, Belgium; 3Antwerp University Hospital, Antwerp, Belgium Critical Care 2007, 11(Suppl 2):P92 (doi: 10.1186/cc5252) Introduction Nonadherence to evidence-based guidelines for the prevention of ventilator-associated pneumonia (VAP) has been reported. As a lack of knowledge may be a barrier for adherence, this study aimed to determine intensive care nurses’ knowledge of evidence-based guidelines for VAP prevention. aztreonam, imipenem, colistin, ciprofloxacin, cefepime, meropenem, aminoglycosides, 19 to meropenem, gentamicin, colistin, tetracycline and two to colistin; four P. aeruginosa: two to piperacillin- tazobactam, two to colistin; one K. pneumoniae: piperacillin- tazobactam, aztreonam, imipenem, ceftazidime, colistin, ciprofloxacin, cefepime, meropenem, aminoglycosides, amoxicillin-clavulanic; Fungi 1: no susceptibility results and three unspecified isolates. Methods This study is a survey using a validated multiple-choice questionnaire, developed to evaluate nurses’ knowledge of VAP prevention and based on a recently published review by Dodek and colleagues [1]. Knowledge of nine nursing-related strategies was evaluated. The questionnaire was distributed and collected during the Flemish Society for Intensive Care Nurses’ annual congress (Ghent, 2005). Demographic data included were gender, intensive care experience, number of critical beds and whether nurses hold a special degree in emergency and intensive care. Excluding fungi and unspecified isolates, we had 8/45 multisensitive isolates and 32/45 isolates sensitive to colistin (32), meropenem (26) and gentamicin (21). According to these data in early and late VAP the most adequate therapeutic combination to cover possible pathogens is meropenem + colistin. Using this combination we cover all possible pathogens and then de-escalate according to susceptibility results. Following the ATS/IDSA guidelines we would cover only 8/45 isolates. Results We collected 638 questionnaires (response rate 75%). Nineteen per cent recognized the oral route as the recommended way for intubation. pneumonia Á Estella García1, A Ruiz Robles2, A Sáinz de Baranda1, M Calero Ruiz2, M Galán1, E Moreno1 1Critical Care Unit and 2Laboratory of Biochemistry, Hospital of Jerez., Spain Critical Care 2007, 11(Suppl 2):P90 (doi: 10.1186/cc5250) Introduction Cytokines play an important role in pulmonary host defense. However, nonuniform findings have been reported about Results Eighty-one patients enrolled into the study; 40% of them were female and the mean age was 71 ± 14. Fifty-one of the S36 Available online http://ccforum.com/supplements/11/S2 patients had TF. When the groups were compared (TF and treatment success), patients with TF were older, had more comorbidities, higher admission and VAP APACHE II scores, Acinetobacter baumanni pneumonia, higher initial bacterial load (colony-forming units/ml) and lower daily carbohydrate intake. Transfusions, bacteremia, infection with multidrug-resistant micro- organismis and steroid therapy were similar across the groups. Among the significant parameters, age and comorbidity were not entered into the logistic regression since the APACHE II score covers these two parameters. VAP with A. baumanni (OR 4.4, 95% CI 1.2–16, P = 0.027), higher VAP APACHE II scores (OR 12, 95% CI, 3–45, P = 0.0001) and lower daily carbohydrate intake (OR 4.4, 95% CI 1.3–15, P = 0.016) were independent predictors for TF in logistic regression analyses. P Myrianthefs1, C Ioannides1, G Fildissis1, S Karatzas1, G Baltopoulos2 1KAT Hospital, Athens, Greece; 2General Hospital of Attiki ‘KAT’, Kifissia, Greece Critical Care 2007, 11(Suppl 2):P93 (doi: 10.1186/cc5253) P Myrianthefs1, C Ioannides1, G Fildissis1, S Karatzas1, G Baltopoulos2 1KAT Hospital, Athens, Greece; 2General Hospital of Attiki ‘KAT’, Kifissia, Greece Critical Care 2007, 11(Suppl 2):P93 (doi: 10.1186/cc5253) Introduction ATS/IDSA [1] guidelines recommend consideration of local microbiologic data when selecting empiric treatment for ventilator-associated pneumonia (VAP) and broad-spectrum empiric therapy for patients with pneumonia caused by MDR pathogens. The purpose was to use local microbiologic data to develop institution-specific guidelines for VAP. pathogens. The purpose was to use local microbiologic data to develop institution-specific guidelines for VAP. Methods We prospectively recorded local microbiologic and susceptibility data in our ICU. Respiratory specimens were tracheal aspirates in all cases and were evaluated by quantitative criteria. Results We had 40 episodes (2,247 ventilator-days) of VAP (40/133 patients) and 45 isolates. In early-onset pneumonia (≤5 days, eight episodes, three with two isolates): six Acinetobacter baumannii: meropenem, colistin, gentamicin (five); three Pseudo- monas aeruginosa: piperacillin, aztreonam, imipenem, ceftazidime, colistin, ciprofloxacin, cefepime, meropenem, aminoglycosides; one Klebsiella pneumoniae: meropenem, colistin, tetracycline; Fungi 1: no susceptibility results. In late-onset pneumonia (>5 days, 32 episodes, two with two isolates): 25 A. baumannii: four to amoxicillin-clavulanic, ceftazidime, piperacillin-tazobactam, aztreonam, imipenem, colistin, ciprofloxacin, cefepime, meropenem, aminoglycosides, 19 to meropenem, gentamicin, colistin, tetracycline and two to colistin; four P. aeruginosa: two to piperacillin- tazobactam, two to colistin; one K. pneumoniae: piperacillin- tazobactam, aztreonam, imipenem, ceftazidime, colistin, ciprofloxacin, cefepime, meropenem, aminoglycosides, amoxicillin-clavulanic; Fungi 1: no susceptibility results and three unspecified isolates. E l di f i d ifi d i l t h d 8/45 Conclusion These results suggest that patients with higher VAP APACHE II scores and pneumonia with A. baumanni and lower carbohydrate intake were at risk for TF. Methods We prospectively recorded local microbiologic and susceptibility data in our ICU. Respiratory specimens were tracheal aspirates in all cases and were evaluated by quantitative criteria. P92 Forty-nine per cent knew that ventilator circuits are to be changed for each new patient only. Heat and moisture exchangers were checked as the recommended humidifier type by 55%, and 13% knew that it is recommended to change them once weekly. Closed suction systems were identified as recommended by 69%, and 20% knew that these must be changed for each new patient only. Respectively 60% and 49% recognized subglottic drainage systems and kinetic beds to reduce the incidence of VAP. Semirecumbent positioning is well known to prevent VAP (90%). The nurses’ average score was 4.2/9, while nurses with >1 year experience and those holding a special degree both scored 4.5/9 (P < 0.001). Conclusions ATS/IDSA [1] guidelines may not be applicable in all institutions or countries and thus clinicians should incorporate local microbiologic data into institution-specific guidelines [2]. References 1. ATS/IDSA: Am J Respir Crit Care Med 2005, 171:388-416. 2. Beardsley JR, et al.: Chest 2006, 130:787-793. 1. ATS/IDSA: Am J Respir Crit Care Med 2005, 171:388-416. 2. Beardsley JR, et al.: Chest 2006, 130:787-793. 1. Dodek P, et al.: Ann Intern Med 2004, 141:305-313. 1. ATS/IDSA: Am J Respir Crit Care Med 2005, 171:388-416. 2. Beardsley JR, et al.: Chest 2006, 130:787-793. 1. Dodek P, et al.: Ann Intern Med 2004, 141:305-313. Administration of meropenem for the treatment of ventilator-associated pneumonia Administration of meropenem for the treatment of ventilator-associated pneumonia Administration of meropenem for the treatment of ventilator-associated pneumonia K Zolotukhin, A Abubakirova District Hospital, Ufa, Russian Federation Critical Care 2007, 11(Suppl 2):P94 (doi: 10.1186/cc5254) K Zolotukhin, A Abubakirova District Hospital, Ufa, Russian Federation Critical Care 2007, 11(Suppl 2):P94 (doi: 10.1186/cc5254) Conclusion Nurses lack knowledge of evidence-based guidelines for VAP prevention. Their schooling and continuing education should include support from current evidence-based guidelines. Reference Conclusion Nurses lack knowledge of evidence-based guidelines for VAP prevention. Their schooling and continuing education should include support from current evidence-based guidelines. Reference Introduction Ventilator-associated pneumonia (VAP) is associated with the greatest mortality among nosocomial infection. Death rates associated with Pseudomonas spp. or with late-onset VAP seem higher. Treatment of these infections is frequently complicated by antibiotic resistance, a problem that has been increasing in recent years. S37 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin infection due to pseudomonas species, acinetobacter species and multidrug-resistant Gram-negative bacilli at enrollment (n = 56), the adequacy of initial antibiotics was 82.4% in the combination group versus 18.8% in the monotherapy group (P < 0.001); this difference was associated with an increase in the microbiological eradication of the infecting organisms (64.1% vs 29.4%, P = 0.05) but no differences in clinical outcomes. Conclusion In patients who have suspected VAP, empiric treatment with combination therapy, as compared with mono- therapy, is safe and is associated with a higher rate of adequate antimicrobial coverage but has no effect on clinical outcomes. Acknowledgements This study was supported by grants from the Canadian Institutes of Health Research and Physicians Services Inc. of Ontario, and unrestricted grants from AztraZeneca Inc., and Bayer Inc. Objective and methods The goal of the study was to evaluate the clinical efficacy of meropenem by continuous infusion administration (CIA) or by bolus intermittent infusion (BII) for the treatment of VAP caused by Pseudomonas aeruginosa. An historic control group with VAP caused by P. aeruginosa who received initial empiric antibiotic therapy with meropenem by BII (n = 32) was compared with a prospective cohort treated with meropenem by CIA (n = 20) in a 12-bed surgical ICU, at a 400-bed surgical complex of a district hospital. We looked for demography, APACHE II score, mortality, attributable mortality for VAP, days on mechanical ventilation (MV), and ICU length of stay. A randomized trial of combination therapy versus monotherapy for the empiric treatment of suspected ventilator-associated pneumonia D Heyland1, P Dodek2, J Muscedere3, A Day3, D Cook4 1Canadian Critical Care Trials Group, Kingston General Hospital, Kingston, Canada; 2St Paul’s Hospital, Vancouver, Canada; 3Kingston General Hospital, Kingston, Canada; 4St Joseph’s Healthcare, Hamilton, Canada Critical Care 2007, 11(Suppl 2):P95 (doi: 10.1186/cc5255) Results Pneumonia was evaluated based on macroscopic grading and microbiological (bacterial count) findings. We were able to maintain anaesthetic, haemodynamic and respiratory support for the study duration of 78 hours. A monobacterial pulmonary infection was established in four out of five animals. Administration of ceftriaxone 1 g daily effectively suppressed all other bacteria. This allowed proliferation of the single strain P. aeruginosa (PA01) we had inoculated with no culture of other organisms. Introduction Delays in adequate antibiotic therapy for ventilator- associated pneumonia (VAP) are associated with poor outcomes, and early use of broad-spectrum antibiotics may improve clinical outcomes. However, indiscriminant use of broad-spectrum antibiotics is associated with the emergence of antibiotic-resistant bacteria, fungal infections, and increased healthcare costs. The purpose of this study was to determine optimal empiric treatment of VAP by comparing a strategy of combination therapy to monotherapy with broad-spectrum antibiotics. Introduction Delays in adequate antibiotic therapy for ventilator- associated pneumonia (VAP) are associated with poor outcomes, and early use of broad-spectrum antibiotics may improve clinical outcomes. However, indiscriminant use of broad-spectrum antibiotics is associated with the emergence of antibiotic-resistant bacteria, fungal infections, and increased healthcare costs. The purpose of this study was to determine optimal empiric treatment of VAP by comparing a strategy of combination therapy to monotherapy with broad-spectrum antibiotics. Conclusions Over a short period of time we were able to reproduce a monoculture ventilator-associated pneumonia in a significant percentage of animals. We successfully developed an animal ICU model that we were able to sustain for 78 hours. This canine model of P. aeruginosa (PA01) ventilator-associated pneumonia is suitable for the application of molecular techniques such as signature-tagged mutagenesis, differential fluorescence induction, and in vivo expression technology. Methods In a multicenter trial, we randomized mechanically ventilated adult patients with suspected VAP that developed after 96 hours in the ICU to receive either meropenem and ciprofloxacin or meropenem alone, as initial therapy. In addition, before starting antibiotics, diagnostic specimens were obtained using either bronchoalveolar lavage with quantitative cultures or standard endotracheal aspirates. P96 Results Significant differences were not found between both groups of patients in sex, age, APACHE II score, and diagnosis. The CIA group showed significantly greater clinical cure than the BII group (CIA 18/20 (90%) vs BII 21/32 965.6%), P = 0.041) and smaller but not significant attributable mortality to VAP (2 of 20 (10%) vs 10 of 32 (31.3%), P = 0.288). A canine model of Pseudomonas aeruginosa ventilator- associated pneumonia using a defined bacterial inoculum A canine model of Pseudomonas aeruginosa ventilator- associated pneumonia using a defined bacterial inoculum A Fahy1, M Gale1, N Chow2, S Webb2 1Royal Perth Hospital, Perth, Australia; 2University of Western Australia, Perth, Australia Critical Care 2007, 11(Suppl 2):P96 (doi: 10.1186/cc5256) Conclusion Our results suggest that administration of meropenem by CIA may have more clinical efficacy than administration by BII for the treatment of VAP, but more studies are required to confirm this. Introduction This prospective pilot study set out to develop an animal model of Pseudomonas aeruginosa that would be suitable for the application of molecular techniques to evaluate virulence in which instillation of a reference strain of P. aeruginosa results in a monoculture ventilator-associated pneumonia. For this purpose, male adult greyhounds were used in an animal research laboratory. Methods The animals were anaesthetised, orally intubated and mechanically ventilated. An inoculum of P. aeruginosa (strain PA01) was instilled into the oropharynx at 1 hour and 8 hours post- intubation. The animals were terminated at 78 hours. Administration of meropenem for the treatment of ventilator-associated pneumonia VAP was treated during 14 days with meropenem (1 g/6 hours intravenously). The antibiotic clinical effect was categorized as cure or failure. Difference between groups were tested by means of Student’s t test end exact chi-square test, using the MedCalc program. We consider values of P < 0.05 as a significant difference. infection due to pseudomonas species, acinetobacter species and multidrug-resistant Gram-negative bacilli at enrollment (n = 56), the adequacy of initial antibiotics was 82.4% in the combination group versus 18.8% in the monotherapy group (P < 0.001); this difference was associated with an increase in the microbiological eradication of the infecting organisms (64.1% vs 29.4%, P = 0.05) but no differences in clinical outcomes. Conclusion In patients who have suspected VAP, empiric treatment with combination therapy, as compared with mono- therapy, is safe and is associated with a higher rate of adequate antimicrobial coverage but has no effect on clinical outcomes. Acknowledgements This study was supported by grants from the Canadian Institutes of Health Research and Physicians Services Inc. of Ontario, and unrestricted grants from AztraZeneca Inc., and Bayer Inc. Conclusion In patients who have suspected VAP, empiric treatment with combination therapy, as compared with mono- therapy, is safe and is associated with a higher rate of adequate antimicrobial coverage but has no effect on clinical outcomes. Acknowledgements This study was supported by grants from the Canadian Institutes of Health Research and Physicians Services Inc. of Ontario, and unrestricted grants from AztraZeneca Inc., and Bayer Inc. P95 A randomized trial of combination therapy versus monotherapy for the empiric treatment of suspected ventilator-associated pneumonia M Niederman1, J Chastre2, K Corkery3, R Fishman3, J Fink3, C Luyt2, M Sanchez4 1Winthrop-University Hospital, Mineola, NY, USA; 25Hôpital Pitié- Salpêtrière, Paris, France; 3Nektar Therapeutics, San Carlos, CA, USA; 4Hospital Principe de Asturias, Alcala de Henares, Madrid, Spain Critical Care 2007, 11(Suppl 2):P97 (doi: 10.1186/cc5257) Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Figure 1 (abstract P97) Despite isolation, MRAB spread over and infected eight more patients in separate rooms and different sections of the ICU 32 days later. Further transmission occurred within a few days: three male patients with multiple trauma (42, 20, and 62 years old; patients 2, 3, and 4), cardia carcinoma (female, 66 years old; patient 5), necrotizing pancreatitis (female, 78 years old; patient 6), splenomegaly owing to polycythaemia vera (male, 74 years old; patient 7 – MRAB diagnosis postmortem), rectal carcinoma (female, 76 years old; patient 8 – isolation because of MRSA infection even before) and respiratory failure after gastric banding (female, 41 years; patient 9). All patients suffered from septic shock with high fever, needed high volume replacement and catecholamines several times and prolonged mechanical ventilation. MRAB was isolated in the tracheal secretion or BAL in all patients, in abdominal drainage (patient 6), and in central venous catheter (patient 5). Environmental investigations showed no problematic circumstances. Colistin i.v. is not available in Germany so it had to be procured from the USA, which caused a delay of treatment for a few days. Another delay occurred because of the rapid growing number of patients who needed Colistin. Patients were treated with an adjusted dosage for 16 days. safety and i.v. antibiotic use with inhaled amikacin (AMK) during adjunctive treatment of intubated patients with Gram-negative pneumonia. Methods A double-blind, placebo-controlled, study of aerosol AMK delivered via the Pulmonary Drug Delivery System (PDDS®; Nektar Therapeutics) in ventilated patients with Gram-negative pneumonia as an adjunctive to i.v. therapy per ATS guidelines. Patients were randomized to receive aerosol containing 400 mg AMK daily with placebo (normal saline) 12 hours later, 400 mg AMK twice daily or placebo twice daily. The i.v. antibiotics (agent and duration) were determined by the attending physician. The AMK peak serum concentration, trough concentrations and tracheal aspirates were drawn. All patients of the ICU were isolated to avoid new infections as a precaution. After convalescence of two patients, all MRAB patients were moved to the IMC, which was converted to an ICU for this period, to isolate infected patients from uninfected. Three out of nine patients died. All these laborious measures with a great expenditure of logistics worked well; no further transmissions were observed. Results The mean number of i.v. Available online http://ccforum.com/supplements/11/S2 antibiotics at the end of the study (mean 7 days) were two times greater with placebo than with twice-daily AMK (P < 0.02) (Figure 1). For daily and twice-daily AMK, the serum Cmax were 1.3 and 1.8 µg/ml (respectively) on day 1, and 2.3 and 3.2 µg/ml on day 3. Mean trough levels were 0.87 and 1.49 µg/ml. Tracheal aspirate levels (mean) on day 3 were 6.9 mg/ml (daily) and 16.2 mg/ml (twice daily). Aerosol AMK was well tolerated with no difference in adverse events across treatment groups. Multidrug-resistant Acinetobacter baumannii susceptible only to colistin outbreak in a cardiac surgical intensive care unit Multidrug-resistant Acinetobacter baumannii susceptible only to colistin outbreak in a cardiac surgical intensive care unit K Papadopoulos, A Tasouli, E Douka, E Manoli, G Saroglou, S Geroulanos Onassis Cardiac Surgery Center, Athens, Greece Critical Care 2007, 11(Suppl 2):P99 (doi: 10.1186/cc5259) Conclusion Repeated doses of adjunctive inhaled AMK to mechanically ventilated patients with Gram-negative pneumonia was safe, well tolerated, and associated with less i.v. antibiotic use than placebo. Objectives Gram-negative bacilli including multidrug-resistant Acinetobacter baumannii (MDR-AB) are responsible for severe ICU-acquired infections, mainly pneumonia and bacteraemia. The aim of this study was to determine the incidence and mortality of this multiresistant strain of Acinetobacter in patients undergoing cardiac surgery, to elucidate the effectiveness of treatment with colistin and to identify whether additional measures were able to prevent and control the dissemination of MDR-AB isolates in our institution. Decrease in intravenous antibiotic use with adjunctive aerosolized amikacin treatment in intubated mechanically ventilated patients with Gram-negative pneumonia Decrease in intravenous antibiotic use with adjunctive aerosolized amikacin treatment in intubated mechanically ventilated patients with Gram-negative pneumonia Results We randomized 740 patients in 28 ICUs in Canada and the United States. The baseline characteristics and etiologies of VAP were similar between groups. There was no difference in 28- day mortality between the combination and monotherapy groups (RR = 1.05, 95% confidence interval 0.78–1.42; P = 0.74). The duration of ICU and hospital stay, clinical and microbiological response to treatment, emergence of antibiotic-resistant bacteria, isolation of Clostridium difficile, and fungal colonization were similar between groups. Combination therapy resulted in a higher rate of adequate empiric therapy compared with monotherapy (93.1% vs 85.3%, P = 0.01). In a subgroup of patients with M Niederman1, J Chastre2, K Corkery3, R Fishman3, J Fink3, C Luyt2, M Sanchez4 1Winthrop-University Hospital, Mineola, NY, USA; 25Hôpital Pitié- Salpêtrière, Paris, France; 3Nektar Therapeutics, San Carlos, CA, USA; 4Hospital Principe de Asturias, Alcala de Henares, Madrid, Spain Critical Care 2007, 11(Suppl 2):P97 (doi: 10.1186/cc5257) Introduction Aerosolized antibiotics may increase lung concentration, reducing the need for i.v. antibiotics. We evaluated S38 P100 Hypercalcaemia resulting from the use of tigecycline in the treatment of multidrug-resistant Acinetobacter in patients with multiorgan failure M Duffy, M Thomas, G Auzinger, W Bernal, E Sizer, J Wendon Institute of Liver Studies, London, UK Critical Care 2007, 11(Suppl 2):P100 (doi: 10.1186/cc5260) Hypercalcaemia resulting from the use of tigecycline in the treatment of multidrug-resistant Acinetobacter in patients with multiorgan failure Hypercalcaemia resulting from the use of tigecycline in the treatment of multidrug-resistant Acinetobacter in patients with multiorgan failure Methods A prospective pharmacokinetic evaluation of amino- glycoside pharmacokinetics during CVVHDF was undertaken. Pharmacokinetic profiles of once-daily doses of intravenous amikacin and gentamicin were obtained from blood and dialysate/ ultrafiltrate samples for 12 critically ill patients treated with CVVHDF using varying flow rates (1 l/hour dialysate plus 2 l/hour filtration fluid or 2 l/hour dialysate plus 2 l/hour filtration fluid, extracorporeal blood flow 200 ml/min). Drug concentrations were measured using an immunoassay. M Duffy, M Thomas, G Auzinger, W Bernal, E Sizer, J Wendon Institute of Liver Studies, London, UK Critical Care 2007, 11(Suppl 2):P100 (doi: 10.1186/cc5260) Introduction Tigecycline (Wyeth) is a new glycylcycline anti- microbial that has been used in the treatment of deep-seated multidrug-resistant Acinetobacter (MDRA) infections. Unexpected changes in routine hematology or serum chemistry have not been reported. Results The mean clearance of gentamicin due to CVVHDF was 2.3 ± 0.3 l/hour (82.1 ± 11.3% of total body clearance (TBC)). The sieving coefficient (SC) was 0.85 ± 0.05. The CVVHDF clearance of amikacin was 2.8 ± 0.5 l/hour (93.0 ± 7.8% TBC). The SC for amikacin was 0.88 ± 0.06. The difference in gentamicin clearance versus amikacin clearance reflects differ- ences in CVVHDF conditions. The mean effluent flow rate among the patient sample treated with gentamicin was 2.7 l/hour compared with 3.5 l/hour for amikacin. There was a strong correlation between creatinine clearance by the filter and measured drug clearance (P < 0.001). Individual patient estimates of aminoglycoside pharmacokinetic parameters (k, Vd) obtained during CVVHDF were used to allow appropriate dosage adjustment. Individualized pharmacokinetic–pharmacodynamic goals (e.g. Cpmax/MIC ratio) were used as indicators of adequate aminoglycoside dosing. The mean gentamicin and amikacin half- lives (approximately 8 hours) during CVVHDF therapy were far shorter than those previously reported in the literature for less efficient forms of renal replacement therapy. Failure to adjust for increased aminoglycoside clearance capacity due to CVVHDF carries a risk of subtherapeutic dosing and therapy failure. P100 Methods All patients were managed within the liver ICU and received standard care. Laboratory data were collected daily and entered onto a specialist database. MDRA-positive cultures from blood, bronchoalveolar lavage, drain fluid or samples taken at laparotomy in the context of systemic inflammatory response syndrome resulted in the initiation of tigecycline 100 mg i.v. followed by 50 mg i.v. 12 hourly. Results Eleven patients received tigecycline treatment for MDRA infections (seven male). Ten patients had a single course whilst one patient had three courses. Underlying disease states were necrotising pancreatitis (one), polytrauma (one), post hepatectomy (one), acute and acute on chronic liver failure (four), and post- orthotopic liver transplant (four). The median duration of treatment was 9 days (range 4–23 days); courses <7 days were because of patient death (2/11). The mean APACHE II score at initiation of therapy was 18 (range 13–26). Four out of 11 survived to ICU discharge and 3/11 to hospital discharge. Tigecycline was well tolerated but increases in corrected calcium were observed in 9/11 patients. The patient that received three courses of treatment had elevations in corrected calcium after each course. For the 11 patients, the mean corrected calcium before treatment with tigecycline was 2.41 mmol/l. The mean corrected calcium on finishing the course increased to 2.59 mmol/l (P = 0.012). There was no correlation between duration of treatment with tigecycline and degree of change in the corrected calcium level (r = 0.08). Hypercalcaemia resolved on discontinuation of the drug; 7/11 survived >7 days after treatment and had a mean corrected calcium of 2.46 mmol/l, which was not significantly different from pretreatment levels (P = 0.94). Conclusion Dosing strategies on the basis of pharmacokinetic analysis of serum drug concentrations, effluent fluid drug concentrations and CVVHDF conditions improved therapeutic outcomes for aminoglycoside drug therapy. P101 Despite significant ‘in vitro’ activity of colistin against this virulent organism and its acceptable safety profile, results were discouraging as only 13% survived. In fact, cure or clinical improvement was observed only in four patients (27%) while 11 patients (73%) developed sepsis and multiple organ failure. A pharmacokinetic basis for improving therapeutic outcomes of aminoglycoside therapy during continuous venovenous haemodiafiltration A Spooner1, O Corrigan1, M Donnelly2 1Trinity College Dublin, Dublin, Ireland; 2Tallaght Hospital, Dublin, Ireland Critical Care 2007, 11(Suppl 2):P101 (doi: 10.1186/cc5261) Scale 1 measures were implemented for the whole 12-month period while Scale 2 for two separate 3-week periods. Following this infection control strategy we achieved intermittent eradication of the pathogen during a 12-month period with continuous function of the SICU. Introduction The objective of this study was to quantify the impact of continuous venovenous haemodiafiltration (CVVHDF) on amino- glycoside pharmacokinetics and to suggest dosing strategies to improve therapeutic outcomes for these drugs in critically ill patients treated with CVVHDF. There has been limited published data on aminoglycoside pharmacokinetics during CRRT. This data deficit had led to subtherapeutic dosing, identified by a retro- spective evaluation of amikacin and gentamicin serum concentra- tions, in patients treated with CVVHDF, undertaken as part of this research. Conclusions Increasing prevalence of MDR-AB in ICU patients demands installation of strict screening and contact precautions. Due to significant mortality of MDR-AB-infected patients, additional measurements like geographic isolation of all positive cases, exclusive medical and nursing personnel, use of separate supplies and facilities and intense environmental surveillance is highly recommended. P98 Management of an outbreak of multiresistant Acinetobacter baumanii infection in a surgical intensive care unit J Lewejohann, M Prang, F Seyfried, A Henning, C Zimmermann, M Hansen, E Muhl, H Bruch University Medical Center Schleswig-Holstein – Campus Lübeck, Germany Critical Care 2007, 11(Suppl 2):P98 (doi: 10.1186/cc5258) Methods A total of 1,451 patients attended the surgical ICU (SICU) after cardiovascular surgery from 1 September 2005 to 31 August 2006. We reviewed the prophylactic measures of the SICU and tried to identify epidemiological links between MDR-AB- infected patients. We implemented a two-scale multiple program. Scale 1 included classical infection control measures (that is, strict contact and droplet isolation, surveillance of throat, nasal and anal flora for MDR pathogens on all patients transferred from other hospitals, separate nursing staff for each infected or colonized case and strict antibiotic policy), while Scale 2 referred to geographic isolation of MDR-AB cases with exclusive medical and nursing personnel, use of separate supplies and facilities and intense environmental surveillance. The first report of multiresistant Acinetobacter baumanii (MRAB) was published in 1994. We report about an outbreak sensitive to Polimyxin only. In June 2006 a German holidaymaker (male, 70 years old; patient 1) in Greece felt dyspnea, thoracic pain and fever. He went to a hospital in Crete. CT indicated left-sided pleural empyema, mediastinal emphysema, pericardial effusion and pneumonia. Rapid deterioration lead to septic shock with need for mechanical ventilation. He came to our ICU (15 beds and six IMC beds) via air transport. Endoscopy showed esophagus perforation with need for operation and endoscopic stenting. Several BALs and a central venous catheter from the beginning showed MRAB with intermediate susceptibility to meropenem/aminoglycosides only. The patient received meropenem and gentamycin at first. Results Fifteen patients were infected by MDR-AB, of which 13 presented respiratory tract infection, one suffered deep surgical site infection and bacteraemia and one from catheter-related infection. They were all treated with intravenous and aerolized colistin in combination with rifampicin or ampicillin and sulbactam. S39 P Gruber, C Gomersall, Q Tian, G Joynt The Chinese University of Hong Kong, New Territories, Hong Kong Critical Care 2007, 11(Suppl 2):P102 (doi: 10.1186/cc5262) P103 Patients and methods We studied 146 patients with skin and soft tissue infections co-infected by HIV and 72 noninfected patients with soft tissue infections aged 18–45 years. All of the patients underwent operations aimed at surgical removal of the dead tissues and pus and received different combinations of antibacterial agents. Twenty-three patients after adequate surgery received Linezolid in doses of 600 mg twice a day intravenously during 3–4 days with oral follow-up of 600 mg twice a day. Linezolid in the treatment of HIV-infected patients with complicated skin and soft tissue infections Linezolid in the treatment of HIV-infected patients with complicated skin and soft tissue infections N Khachatryan1, I Dizengof2, G Smirnov2 1Moscow State University of Medicine and Dentistry, Moscow, Russian Federation; 2Hospital of Infectious Diseases N3, Moscow, Russian Federation Critical Care 2007, 11(Suppl 2):P104 (doi: 10.1186/cc5264) Introduction The incidence of HIV-infected patients with complicated skin and soft tissue infections has risen. Because of advanced immune suppression, slower responses to antibacterial treatment, and increased risk of bacteraemia relative to noninfected patients, the choice of initial appropriate empiric antibacterial therapy is an important aspect of care for HIV-infected patients. However, in recent years a dramatic increase of the resistance among Staphylococci to all classes of antimicrobial agents, including glycopeptides, has been reported. Introduction The incidence of HIV-infected patients with complicated skin and soft tissue infections has risen. Because of advanced immune suppression, slower responses to antibacterial treatment, and increased risk of bacteraemia relative to noninfected patients, the choice of initial appropriate empiric antibacterial therapy is an important aspect of care for HIV-infected patients. However, in recent years a dramatic increase of the resistance among Staphylococci to all classes of antimicrobial agents, including glycopeptides, has been reported. Conclusions Total adsorption is low and unlikely to be of clinical significance. Adsorption and the sieving coefficient are independent of the type of haemofilter membrane. The sieving coefficient of oseltamivir carboxylate is 1, therefore clearance during haemofiltration can be estimated from the ultrafiltration rate. Available online http://ccforum.com/supplements/11/S2 influenza A/H5N1 develop acute renal failure. A proportion will require haemofiltration. There are no data to determine the elimination of oseltamivir carboxylate (the active metabolite) by haemofiltration. An in vitro study to determine elimination by measuring the adsorption and sieving coefficient of oseltamivir carboxylate using two haemofilter types was undertaken. and 34 once daily (OD group), for nosocomial pneumonia (n = 14), skin and soft tissue infection (burn and nonburn including diabetic foot) (n = 13), bacteraemia (n = 10), intra-abdominal infection (n = 8), bone and joint infection (n = 6) and as pre-emptive therapy for severe trauma (n = 13). In the OD group, mean trough levels remained at 9.64 µg/ml from days 2 to 4 and peak levels remained at a mean of 24.84 µg/ml. In the BD group, mean trough levels increased by 5.65 µg/ml/24 hours to 21.8 µg/ml by day 4; the mean peak level increased by 5.06 µg/ml/24 hours to 43.89 µg/ml by day 4. Methods An in vitro one-compartment model of continuous veno- venous haemofiltration was used. In phase 1 oseltamivir carboxy- late adsorption to the haemofilter and circuit was studied by circulating a blood–crystalloid mixture containing clinically relevant concentrations of oseltamivir carboxylate through a haemofilter circuit and returning the ultrafiltrate to the mixing chamber. In phase 2 the ultrafiltrate was removed and replaced with a bicarbonate-based fluid to enable calculation of the sieving coefficient. The study was repeated 10 times with two haemofilter types: polyamide and polyacrylonitrile (PAN). Finally, oseltamivir carboxylate was added to the blood–crystalloid mixture without circulation through the circuit to determine its stability in solution. Blood samples collected were assayed by HPLC-MS/MS. Conclusion Higher trough levels of glycopeptides (15–20 µg/ml) are targeted to improve efficacy and reduce resistance development. In the OD group the conventional target of 10 µg/ml was achieved, whilst in the BD arm 20 µg/ml was exceeded for 60% of the time by day 2 and 100% by day 4. BD dosing is recommended for most patients with severe infections, particularly those that are critically ill. No premature discontinuations or adverse events were reported during the study. P104 Results Oseltamivir carboxylate remained stable in solution (mean percentage change from baseline at 30 min: +3.97%, at 60 min: +1.91%, at 90 min: +2.36%). The mean ± SD initial oseltamivir carboxylate concentrations for the PAN (346 ± 85 µg/l) and polyamide (453 ± 185 µg/l) showed no significant difference. The mean ± SD adsorption at 90 min was 58.18 ± 17.84 µg for PAN and 75.22 ± 36.88 µg for polyamide haemofilters. There was no statistical difference in adsorption between the haemofilters. The initial drug concentration was a significant predictor of adsorption (r2 = 0.734). The mean ± SD sieving coefficient of oseltamivir carboxylate for PAN (1.06 ± 0.04) and polyamide (1.03 ± 0.06) haemofilters showed no statistical difference between the haemofilters. P102 An in vitro study of elimination of oseltamivir carboxylate by haemofiltration P Gruber, C Gomersall, Q Tian, G Joynt The Chinese University of Hong Kong, New Territories, Hong Kong Critical Care 2007, 11(Suppl 2):P102 (doi: 10.1186/cc5262) Conclusion Tigecycline is well tolerated but appears to be associated with an elevated corrected calcium in critically ill patients. This returns to baseline values on discontinuation of the drug. Conclusion Tigecycline is well tolerated but appears to be associated with an elevated corrected calcium in critically ill patients. This returns to baseline values on discontinuation of the drug. Introduction Oseltamivir is the drug of choice for treatment of avian influenza A/H5N1 infection. One-quarter of patients with S40 Available online http://ccforum.com/supplements/11/S2 A post-authorization survey to evaluate plasma concentrations of teicoplanin in adult hospitalized patients treated for sepsis in Gauteng, South Africa A Brink1, G Richards2, and the G Uts Study Group 1Du Buisson, Bruinette and Partners, Johannesburg, South Africa; 2Johannesburg Hospital, Johannesburg, South Africa Critical Care 2007, 11(Suppl 2):P103 (doi: 10.1186/cc5263) Results The most frequent pathogens are Staphylococci in both groups of patients with soft tissue infections: 56% was noted among the noninfected patients and 61% among the HIV-infected patients. MRSA was identified in 30% of Staphylococci in HIV- infected patients. Among the patients receiving Linezolid, MRSA was identified in nine cases; in two cases vancomycin-intermediate S. aureus strains, and in one case vancomycin-resistant S. aureus strain. In three cases we revealed Staphylococcus bacteraemia, in one case MRSA bacteraemia in patient with retroperitoneal phlegmon. Objective This study measured and analyzed plasma concen- trations of teicoplanin in patients >18 years in the first 4 days of administration. Methods This was an open-label, multicentre, observational study in patients receiving teicoplanin for suspected or diagnosed Gram- positive infection. Data collection included demographics, method of administration, loading and maintenance doses, creatinine and adverse events. Trough and peak concentrations were determined 15 minutes prior to drug administration and 60 minutes after. Serum was separated and stored at –20°C until analysis. Levels were determined with an Abbott TDx®/FLx® analyzer and Seradyn Teicoplanin Innofluor assay kits. Seradyn internal teicoplanin controls were run within and between each batch. Mean trough and peak plasma levels were calculated for 4 days of therapy. Results Seventy-four patients with complete records were analyzed and whilst all patients received an 800 mg loading dose on day 1, 40 received 400 mg twice daily thereafter (BD group) A statistical difference was identified in duration of high temperature, purulence and wound healing in comparison with patients receiving different combinations of antibacterial agents. All patients receiving Linezolid were discharged from the hospital. The length of stay was 17 ± 1.67 days in comparison with patients receiving other antibacterial agents (from 19.52 ± 1.37 to 20.3 ± 1.46 days). The length of stay in hospital among the noninfected patients with soft tissue infection was 9.5 days. P107 Results A high incidence of ESBL producing E. coli and Klebsiellae was observed (85.8%). Meropenem (9.3%) and imipenem (2.8%) resistance in the ESBL producers was seen. On multivariate analysis with logistic regression, a central venous catheter was an independent risk factor for ESBL acquisition (P = 0.01, OR 3.55, 95% CI 1.4–9.02). The median ICU length of stay was 3.5 days and 3 days in the ESBL and non-ESBL groups, respectively. The overall mortality was 13.28% and 13.6% in the two groups, respectively. Microbiological outcomes were similar to clinical outcome, with 83.6% microbiologic success rate among ESBL producers. The contamination by Staphylococcus epidermidis in the intensive care unit The contamination by Staphylococcus epidermidis in the intensive care unit K Bruno1, D Albanese1, E Fabbri1, F Petrini1, M Scesi1, F Bruno2 1SS Annunziata, Chieti, Italy; 2Villa Serena Clinic, Pescara, Italy Critical Care 2007, 11(Suppl 2):P107 (doi: 10.1186/cc5267) Introduction The most important way to prevent infections in the ICU is to respect asepsis during the numerous invasive procedures to which patients are exposed (central venous catheter, urinary catheter, orotracheal tube (OTT), fibrobronchoscopy (FOB), surgical drainages, patients nursing, surgical medications). Conclusion ESBL producing E. coli and Klebsiellae are problematic pathogens in our ICUs. Emergence of carbapenem resistance is of serious concern. Stringent infection control practices such as aseptic insertion and proper handling of central lines within the ICU should be followed by all. Methods The contaminations from Staphylococcus epidermidis have been valued in main infection centres on 951 patients admitted to our ICU for more than 72 hours from 1996 to 2005. From 2000, rigid asepsis protocols have been introduced for the cleansing of staff hands with the use of disinfectants such as Clorexidina and alcoholic gel. A clinico-microbiological study of extended spectrum β-lactamases in the intensive care unit Y Mehta, K Bomb, S Jalota, A Arora, N Trehan Escorts Heart Institute and Research Centre, New Delhi, India Critical Care 2007, 11(Suppl 2):P105 (doi: 10.1186/cc5265) Introduction Extended spectrum β-lactamase (ESBL) producing organisms are emerging as common nosocomial pathogens in the ICU worldwide. Early detection and prevention of spread is the primary measure to overcome the challenge posed by these difficult to treat ESBL infections. The aim of this study was to find the incidence, risk factors and microbiological and clinical outcome of patients infected with ESBL producing Escherichia coli and Klebsiellae in the ICU of a tertiary care cardiac center in India. Results Eighty-five patients in phase I and 55 patients in phase II were enrolled. Third-generation cephalosporins were the primary antibiotic in 75.2% of cases in phase I and in 1.8% of cases in phase II (P < 0.001). The incidence of ESBL was 62.3% in phase I and it came down to 34.5% in intervention phase II (P < 0.01). Conclusion Data from this intervention study support the concept that third-generation cephalosporins are of substantial importance in the emergence of ESBL; by decreasing the level of third- generation cephalosporin use and increasing the piperacillin/ tazobactum use, their was a notable reduction in the acquisition rate of ESBL producing E. coli. Methods A prospective, observational, case–control study of 150 patients was conducted from August 2004 to July 2005. ESBL testing was performed by the phenotypic confirmatory disc diffusion method. Clinical data and risk factors for ESBL acquisition were analysed as well as the antimicrobial therapy, and clinical and microbiological outcomes were studied. A post-authorization survey to evaluate plasma concentrations of teicoplanin in adult hospitalized patients treated for sepsis in Gauteng, South Africa Modification of antibacterial treatment was not required in the group of patients Results Seventy-four patients with complete records were analyzed and whilst all patients received an 800 mg loading dose on day 1, 40 received 400 mg twice daily thereafter (BD group) S41 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin preventing their clonal outbreak, and the risk factors for ESBL include intensive antibiotic exposure (especially third-generation cephalosporin monotherapy). The present study was performed to determine the impact of using piperacillin/tazobactum in reducing the acquisition rate of ESBL producing Gram-negative bacteria in the ICU. receiving Linezolid. No significant laboratory abnormalities and side effects were noted. We did not reveal statistical differences in the platelet count in group of patients receiving Linezolid (5 days after operation 213 ± 26.0/mm3) in comparison with the group receiving other antibacterial agents (256 ± 32/mm3). Thrompocytopenia is characterized to HIV-infected patients, but did not deteriorate in patients receiving Linezolid Methods This open-label, prospective study was carried out in 140 adult patients admitted to the ICU over a period of 9 months, and was divided into two phases. Phase I (pre-intervention phase, 0–3 months): upon admission to the ICU, besides standard investigations, additional rectal swab cultures were taken for detection of ESBL within and after 48 hours of admission, and were repeated every 7 days of the stay in the ICU. Routinely prescribed antibiotics were allowed. Phase II (intervention phase, 4–9 months): this was subdivided into (a) first 3 months (4–6 months): piperacillin/tazobactum was the primary antibiotic used (more than 50% replacement of cephalosporins), and (b) last 3 months (7–9 months): here again, rectal swab cultures were taken and piperacillin/tazobactum was the primary antibiotic used. McNemar’s test and Fisher’s exact test were used for statistical analysis. Conclusion Linezolid in the complex treatment of HIV-infected patients with complicated skin and soft tissue infections may improve the results of therapy and may be used for initial empirical intravenous-to-oral antibacterial therapy. P106 Impact of antibiotic utilization measures on acquisition rate of extended spectrum β-lactamase enzymes producing bacteria Available online http://ccforum.com/supplements/11/S2 P108 their critical illness status, some patients were subject to quarantine. Improving HH was achieved by promoting alcohol- based hand disinfection, refraining all health care workers (HCW) from wearing hand jewellery or artificial fingernails, supplying HCW with clip watches and by developing promotional material. Education of HCW regarding principles and techniques of HH was provided by the IC department, supervised by link persons selected among medical, nursing and domestic staff. The number of new hospital-acquired MRSA infections per 1,000 admissions was recorded. Compliance to HH was measured by observation, microbiological analysis of total counts of colony-forming units on fingerprints, and by monitoring the consumption of hand-rub solutions (HH moments per patient-care day). Colonization and infection by MRSA in critically ill patients L Lorente, R Santacreu, J Iribarren, J Jimenez, M Martin, M Mora Hospital Universitario de Canarias, Santa Cruz de Tenerife, Spain Critical Care 2007, 11(Suppl 2):P108 (doi: 10.1186/cc5268) Objective To determine the incidence of colonization and infection by MRSA in critically ill patients. Methods A prospective study during 30 months of the patients admitted to the ICU for 24 hours or more. Throat swab, tracheal aspirate and urine were taken on admission and twice weekly. The colonization and infection by MRSA were registered. The infections were diagnosed according to CDC criteria. The infections were classified based on throat flora as: primary endogenous (PE) when they were caused by germs that were already colonizing the throat on the ICU admission; secondary endogenous (SE) when they were caused by germs that were not colonizing the throat on the ICU admission but were acquired during the stay in ICU; or exogenous (EX) when they were caused by germs that were not colonizing the throat. The infections were classified based on the onset moment: early onset (EO) were those developed during the first 4 days of the ICU stay; and late onset (LO) were those developed 5 days after ICU admission. Results A selective MRSA admission screening policy increased the carrier detection rate up to 15%, compared with 1–2% in our preoperative outpatient clinic. The observed compliance to HH increased from 49% to 79% and consumption of hand-rub solution from 6 to 33 l per 1,000 patient-days. The number of HH moments increased from 19 to 47. Total counts of colony-forming units less than 50 improved from 39% of the analyses to 55%. P109 Methods A retrospective post-hoc analysis of the prospective, multicentre VAP study, which enrolled patients with a clinical suspicion of VAP, admitted to an ICU for >96 hours and on mechanical ventilation (MV) for >48 hours. Airway cultures were done on randomization. Patients with positive Candida cultures from other sites were excluded. The remaining patients were divided into two groups according to their Candida airway culture status. Demographics, admission diagnosis, comorbidities, PaO2/ FiO2 ratio and APACHE II score were recorded at randomization. The length of MV, ICU and hospital stay were compared, as well as hospital, ICU and 28-day mortality. Appropriate parametric statistical tests were applied according to data. Results Of the 739 patients enrolled in the VAP study, 639 were included for analysis: 114 had Candida airway colonization (C) and 525 did not (NC). No significant differences were noted in demographics and APACHE II score (20 ± 6 vs 20 ± 6, P = 0.37) except more frequent admission for sepsis (7.0% vs 2.1%, P = 0.005) and respiratory conditions (21.9% vs 14.3%, P = 0.04) in group C. More colonized patients were on antibiotics at randomization (81.6% vs 56.7%, P < 0.001). A trend for increased Methods A retrospective post-hoc analysis of the prospective, multicentre VAP study, which enrolled patients with a clinical suspicion of VAP, admitted to an ICU for >96 hours and on mechanical ventilation (MV) for >48 hours. Airway cultures were done on randomization. Patients with positive Candida cultures from other sites were excluded. The remaining patients were divided into two groups according to their Candida airway culture status. Demographics, admission diagnosis, comorbidities, PaO2/ FiO2 ratio and APACHE II score were recorded at randomization. The length of MV, ICU and hospital stay were compared, as well as hospital, ICU and 28-day mortality. Appropriate parametric statistical tests were applied according to data. Candida airway colonization is associated with worse outcomes Candida airway colonization is associated with worse outcomes M Delisle1, D Williamson2, M Perreault3, M Albert2, X Jiang4, D Heyland4 1Hopital de l’Enfant-Jésus, Québec, Canada; 2Hopital du Sacré- Coeur de Montréal, Canada; 3Hopital Général de Montréal, Centre Universitaire de Santé McGill, Montréal, Canada; 4Queens University, Kingston, Canada Critical Care 2007, 11(Suppl 2):P110 (doi: 10.1186/cc5270) M Delisle1, D Williamson2, M Perreault3, M Albert2, X Jiang4, D Heyland4 1Hopital de l’Enfant-Jésus, Québec, Canada; 2Hopital du Sacré- Coeur de Montréal, Canada; 3Hopital Général de Montréal, Centre Universitaire de Santé McGill, Montréal, Canada; 4Queens University, Kingston, Canada Critical Care 2007, 11(Suppl 2):P110 (doi: 10.1186/cc5270) Introduction Candida airway colonization is common in mechanically ventilated ICU patients. Its significance and impact on outcomes are not well defined. We aimed to describe Candida airway colonization and assess clinical outcomes of patients with a clinical suspicion of ventilator-associated pneumonia (VAP) colonized with Candida. Conclusions In our series, most of the infections caused by MRSA were pneumonias, had a late onset and were secondary endogenous. Available online http://ccforum.com/supplements/11/S2 Concomitantly, a decrease in MRSA attack rate from six to one new case per 1,000 patient-days was seen. Conclusion An ED tailored selective MRSA screening and contact isolation protocol and a change in HH behaviour in the ED have mainly contributed to a decrease of the MRSA attack rates in our hospital far below the national rate. p y Results Were admitted 1,582 patients, 953 males (60.24%). The mean age was 57.91 ± 18.83 years. The mean APACHE II score was 13.95 ± 8.93. Admission diagnoses were: 737 (46.59%) heart surgery, 189 cardiological (11.95%), 196 neurologic (12.29%), 185 trauma (11.69%), 120 respiratory (7.59%), 104 digestive (6.57%) and 51 intoxication (3.22%). Mortality was 14.79% (234 patients). A total of 36 patients had colonization by MRSA, two patients at ICU admission and 34 patients during the ICU stay. We documented 24 infections caused by MRSA (four EO and 20 LO; zero PE, 21 SE and three EX): 18 pneumonias (three EO and 15 LO; zero PE, 15 SE and three EX), three primary bacteremias (one EO and two LO; three SE), two surgical wound infections (two LO and SE) and one pressure sore infection (one LO and SE). Death occurred in 7/24 patients (29.17%) with infection caused by MRSA: 6/18 (33.33%) pneumonias, 1/3 (33.33%) primary bacteremias and 0/3 other infections. Impact of an MRSA search and destroy policy in a tertiary care emergency department Impact of an MRSA search and destroy policy in a tertiary care emergency department Impact of antibiotic utilization measures on acquisition rate of extended spectrum β-lactamase enzymes producing bacteria Results From 1996 to 2005 the percentage of contamination from S. epidermidis has been 24.7% (22% in respiratory tracts, 8% in the urinary system, 41% in central venous catheter, 19% in the blood, 10% in other places). From 2000 to 2005 there has been a sensible reduction of 3%. A Gurnani1, A Jain1, S Sengupta1, G Rambhad2 1Kailash Hospital, Noida, India; 2Wyeth, Bombay, India Critical Care 2007, 11(Suppl 2):P106 (doi: 10.1186/cc5266) A Gurnani1, A Jain1, S Sengupta1, G Rambhad2 1Kailash Hospital, Noida, India; 2Wyeth, Bombay, India Critical Care 2007, 11(Suppl 2):P106 (doi: 10.1186/cc5266) Conclusion The introduction in the last 5 years of strict protocols in order to control asepsis in our ICU, combined with the use of Clorexidina and alcoholic gel, have drastically reduced the contamination from S. epidermidis. Introduction Antibiotic resistance patterns are continually changing; a new problem has been the emergence of Gram-negative bacteria, primarily Escherichia coli and Klebsiellae pneumoniae, producing extended spectrum β-lactamase enzymes (ESBL). Antibiotic use measures are presumably the most important intervention in S42 Available online http://ccforum.com/supplements/11/S2 P112 Methods During a 2-year period (2005–2006), a study was performed in a 17-bed general ICU, divided into two phases: a case–control retrospective study in which controls comprising a representative subpopulation with severe bacterial sepsis were compared with cases (patients with Candida sepsis) with respect to multiple demographic and clinical factors in a univariate analysis; and a prospective phase creating a preemptive scheme based on results from the retrospective part followed by progressively implementing it among targeted patients. Results Over a 22-month period, 2,509 critically ill patients were evaluated. Candida spp. was isolated from any site in 141 patients (5.6%), while 10 patients (0.4%) presented ICU-acquired candidemia. They were all hospitalized for more than 7 days (range 7–34 days) in the ICU and had been exposed to broad-spectrum antibiotics (>3 agents). The mean age was 68 years (range 50–82 years) and the mean ICU stay 28 days. Candidemia appeared at a mean of 15.8 days after ICU admission. Candida albicans was the most common isolated pathogen. Candiduria in any count was detected in 12 patients but none of them experienced candidemia, while in seven patients Candida was isolated from urine and the respiratory tract. Six patients had major postoperative complica- tions. Mortality due to candidemia was 60%. All patients received appropriate antifungal treatment. Prophylactic antifungal treatment was used in patients with multifocality colonization and in patients spending more than 7 days in the ICU after cardiac surgery. Results Identified were 28 cases with Candida sepsis and 50 controls with severe bacterial sepsis with an all-cause mortality rate of 40.2%. The mortality rate for Candida sepsis was 46.4% with an attributable risk of 10/100 and was associated with a worse score of systemic injury (SAPS II = 51.7 ± 15.0), comparing with a mortality rate of 35.7% and SAPS II = 38.8 ± 13.3 for bacterial sepsis. Candida sepsis was always accompanied by concurrent bacterial sepsis (2.8 ± 1.1 microorganisms/patient isolated from blood cultures). Identified were risk factors with great significance in addition to already known ones: Candida colonization (OR = 3.4), diabetes (OR = 3.2), number of antibiotics used (OR = 2.9), a nothing per os regimen (OR = 2.63), ICU length of stay (OR = 1.97), length of antibiotic use (OR = 1.74), pancreatitis (OR = 1.7), shock at admission (OR = 1.54), ventilator days/ICU stay ratio (days)(OR = 1.4), multiple resistant bacterial strains (OR = 1.5). P112 Candida colonization and risk of candidemia in a cardiac surgical intensive care unit E Douka A Mastoraki G Stravopodis G Saroglou S Geroulanos Candida colonization and risk of candidemia in a cardiac surgical intensive care unit E Douka, A Mastoraki, G Stravopodis, G Saroglou, S Geroulanos Onassis Cardiac Surgery Center, Athens, Greece Critical Care 2007, 11(Suppl 2):P112 (doi: 10.1186/cc5272) Candida colonization and risk of candidemia in a cardiac surgical intensive care unit M Geube, S Milanov, G Georgiev Pirogov Emergency Institute, Sofia, Bulgaria Critical Care 2007, 11(Suppl 2):P111 (doi: 10.1186/cc5271) Introduction The aim of the study was to evaluate the incidence of Candida colonization in a cardiac surgical ICU, the predisposing risk factors and the impact of candidemia on outcome. Introduction Candida spp. is the third most common reason for sepsis in the ICU, not differentiating our results from the classic pattern of ICU-acquired infection. Prevention of sepsis develop- ment and identification of potentially modifiable risk factors are important goals in intensive care patents. Preemptive treatment of Candida sepsis accepted by some authors is defined as an early antifungal treatment given to patients with evidence of substantial colonization in the presence of multiple risk factors for Candida infection prior to establishing the diagnosis by cultures. Our aim was to form a focused group of patients with significant risk for Candida sepsis; to prove the feasibility and efficacy of our pre- emptive scheme for antimycotic treatment in order to reduce the risk of development of proved Candida sepsis. Methods In an effort to answer this question a prospective study was conducted among patients admitted to our 16-bed cardiac surgical intensive care unit ICU during 1 December 2004–30 October 2005. Candida colonization and candidemia were identified. Fungal colonization was defined as colonization index exceeding 0.20 (3 g, at least two samples of seven growing Candida spp.). Candidemia was defined as the isolation Candida spp. in at least one blood culture in a patient with temporally related clinical signs. The demographic characteristics of patients who developed candidemia, as well as the underlying disease and comorbidities, were recorded. P111 Fungal infections in the intensive care unit? Another approach for defining a target group of patients who benefit from implementing preemptive antimycotic treatment E Dhondt, R Duerinckx, I Laes, A Schuermans UZ Leuven, Leuven, Belgium Critical Care 2007, 11(Suppl 2):P109 (doi: 10.1186/cc5269) ICU (21.1% vs 13.9%, P = 0.06) and 28-day mortality (23.7% vs 16.4%, P = 0.08) and a significant difference in hospital mortality (34.2% vs 21.1%, P = 0.003) was observed in group C. A trend was found for increased median length of ICU stay (14.1 vs 11.6 days, P = 0.07) and duration of MV (10.9 vs 8.1, P = 0.06). Hospital stay was significantly longer (59.9 vs 38.6 days, P = 0.006) in group C. Conclusions Based on our results, we accepted an algorithm for performing a preemptive therapy for which we observed clinical efficacy and which we considered indicated the following target groups of patients: with presence of clinical features of unresolving sepsis plus three defined risk factors (PPV > 70%) in a patient with length of ICU stay >20 days; lack of clinical improvement with combined antibiotic treatment against established bacterial strains; evidence of sepsis accompanied with multifocal Candida coloniza- tion of sterile body spaces. Candida colonization without risk factors requires continuous monitoring. The most important pre- sumption to accept the preemptive strategy for a certain patient is to have a serious clinical conviction that there is an invasive fungal infection but it is still pending to be proved. Conclusion Respiratory tract Candida colonization in patients with clinical suspicion of VAP is associated with an increased burden of illness. Whether Candida colonization is responsible for worse outcomes remains to be established. E Dhondt, R Duerinckx, I Laes, A Schuermans UZ Leuven, Leuven, Belgium Critical Care 2007, 11(Suppl 2):P109 (doi: 10.1186/cc5269) E Dhondt, R Duerinckx, I Laes, A Schuermans UZ Leuven, Leuven, Belgium Critical Care 2007, 11(Suppl 2):P109 (doi: 10.1186/cc5269) Introduction An emergency department (ED) is a major hospital entrance and its case mix consists of patients at high risk of both introducing and acquiring infections. Alerted by the rise of hospital- acquired MRSA infections, the ED of a teaching hospital set up an ED infection control (IC) programme. The programme and its impact are discussed. Results Of the 739 patients enrolled in the VAP study, 639 were included for analysis: 114 had Candida airway colonization (C) and 525 did not (NC). No significant differences were noted in demographics and APACHE II score (20 ± 6 vs 20 ± 6, P = 0.37) except more frequent admission for sepsis (7.0% vs 2.1%, P = 0.005) and respiratory conditions (21.9% vs 14.3%, P = 0.04) in group C. More colonized patients were on antibiotics at randomization (81.6% vs 56.7%, P < 0.001). A trend for increased Methods The campaign consisted of the appliance of a proactive MRSA admission screening protocol, selective contact isolation (quarantine) and improving hand hygiene (HH). The MRSA admission screening strategy took into account past medical history or actual suspicion of MRSA carriage, transfers from other hospitals and long-term care facilities and admission of hospitalised patients to the ED for upgrading of care. According to S43 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Conclusions Based on our results, we accepted an algorithm for performing a preemptive therapy for which we observed clinical efficacy and which we considered indicated the following target groups of patients: with presence of clinical features of unresolving sepsis plus three defined risk factors (PPV > 70%) in a patient with length of ICU stay >20 days; lack of clinical improvement with combined antibiotic treatment against established bacterial strains; evidence of sepsis accompanied with multifocal Candida coloniza- tion of sterile body spaces. Candida colonization without risk factors requires continuous monitoring. The most important pre- sumption to accept the preemptive strategy for a certain patient is to have a serious clinical conviction that there is an invasive fungal infection but it is still pending to be proved. P113 reticular neoplasias, solid organ transplants, and mainly in patients with AIDS [1]. To our knowledge, the toxoplasmosis seropositivity rate in ICU patients who have critical illness induced immuno- suppression is not yet investigated. We studied the seropositivity incidence of T. gondii in ICU patients by assessing IgG and IgM antibodies. Consequences of cytomegalovirus reactivation in patients with severe sepsis A Heininger, K Hamprecht, I Fischer, A Baumeister, C Meisner, H Häberle University Hospital, Tübingen, Germany Critical Care 2007, 11(Suppl 2):P115 (doi: 10.1186/cc5275) Introduction Sepsis has been identified as a risk factor for cyto- megalovirus (CMV) reactivation in nonimmunosuppressed patients in the ICU setting. Here we present a double-blinded prospective study assessing the consequences of CMV reactivation in non- immunosuppressed patients with severe sepsis. Conclusion The observational nature of this study precludes the establishment of any causality. This research merely documents the experiences of ICU patients who have been prescribed i.v. fluconazole therapy. Our results showed high mortality rates in the enrolled ICU patients. Patients developing adverse events and complications requiring a switch in fluconazole experienced worse outcomes u osupp essed pa e s se e e seps s Methods In three (two surgical, one medical) ICUs of a German university hospital, adult patients were screened for severe sepsis. Patients with recently occurring severe sepsis (<72 hours) were enrolled if their anti-CMV IgG titer was positive. The exclusion criterion was a manifest immunodeficiency. At enrollment the SAPS II was assessed. Patients were monitored for CMV reactivation weekly until death or hospital discharge by qualitative and quantitative PCR and virus culture. CMV reactivation was defined as CMV DNA detection or virus isolation. Patients with (CMV+) and without CMV reactivation (CMV–) were compared regarding inhospital mortality, duration of mechanical ventilation, length of stay (LOS) in the ICU and the hospital. Data were analysed using the Wilcoxon score rank sum test and chi-square test. The level of significance was set to 0.05. Results CMV reactivation was observed in 38 out of 99 patients. Both groups (CMV+/CMV– patients) were quite similar in regard to gender and age at study enrollment. Interestingly, the median SAPS II was higher in CMV– patients (47 vs 42; P < 0.013). Accordingly, a lower mortality rate was anticipated for CMV+ patients compared with the CMV– group. Contrary to expectations, mortality did not differ between both groups (CMV+ 36.8% vs CMV– 42.6%; P > 0.67). This may point to a relatively pp p p Methods In three (two surgical, one medical) ICUs of a German university hospital, adult patients were screened for severe sepsis. Patients with recently occurring severe sepsis (<72 hours) were enrolled if their anti-CMV IgG titer was positive. The exclusion criterion was a manifest immunodeficiency. At enrollment the SAPS II was assessed. Reference 1. Ferreira MS, Borges AS: Mem Inst Oswaldo Cruz 2002, 97:443-457. 1. Ferreira MS, Borges AS: Mem Inst Oswaldo Cruz 2002, 97:443-457. Results A total of 303 patients were enrolled. Fluconazole was used initially as prophylaxis in 29 (9.6%) patients, preemptive therapy in 85 (28.1%) patients, empiric therapy in 140 (46.2%) patients and as definitive therapy in 49 (16.2%) patients. Thirty-six patients switched from fluconazole to a broader spectrum anti- fungal agent, and seven received a second concomitant antifungal drug. Reasons for switching therapies included lack of response due to suspected resistance, documented resistance or clinical reasons other than resistance. Thirty-two patients (10.6%) experienced fluconazole-related adverse events. The overall study mortality rate was 41.9% (127/303 patients). Mortality was significantly associated with switching i.v. treatment (odds ratio 5.0; 95% CI 2.3–11.1) and the presence of adverse events (odds ratio 4.1; 95% CI 1.8–9.2). Consequences of cytomegalovirus reactivation in patients with severe sepsis Patients were monitored for CMV reactivation weekly until death or hospital discharge by qualitative and quantitative PCR and virus culture. CMV reactivation was defined as CMV DNA detection or virus isolation. Patients with (CMV+) and without CMV reactivation (CMV–) were compared regarding inhospital mortality, duration of mechanical ventilation, length of stay (LOS) in the ICU and the hospital. Data were analysed using the Wilcoxon score rank sum test and chi-square test. The level of significance was set to 0.05. Longitudinal evaluation of intensive care unit-related fluconazole use in Spain and Germany H Wissing1, J Ballus2, G Nocea3, K Krobot4, P Kaskel4, R Kumar5, P Mavros5 1Universitatsklinkum Frankfurt, Germany; 2Hospital Universitari de Bellvitge, L’Hospitalet del Llobregat, Barcelona, Spain; 3Universitaria de Bellvitge, Barcelona, Spain; 4MSD Sharpe and Dohme GmbH, Munich, Germany; 5Merck and Co., Inc., Whitehouse Station, NJ, USA Critical Care 2007, 11(Suppl 2):P113 (doi: 10.1186/cc5273) Materials and methods One hundred and three ICU patients with the mean age of 53.9 ± 13.9 years (51 men, 52 women) and 78 healthy volunteers with the mean age of 51.4 ± 9.2 years (39 men, 29 women) as a control group were included in the study. Anti- T. gondii IgG and IgM antibodies were determined by ELISA. Statistical analyses were done with the chi-square test and Kolmogorov–Smirnov one-sample test. P < 0.05 was considered as statistical significance. Objective To evaluate utilization patterns and outcomes associated with i.v. fluconazole therapy within ICUs in Spain and Germany. Objective To evaluate utilization patterns and outcomes associated with i.v. fluconazole therapy within ICUs in Spain and Germany. Objective To evaluate utilization patterns and outcomes associated with i.v. fluconazole therapy within ICUs in Spain and Germany. Methods A prospective longitudinal observational study was conducted within 14 hospital ICUs in Spain and five in Germany. Patients on i.v. fluconazole therapy were included and were followed over one hospitalization period (admission until discharge). Data were collected during 2004, using electronic case report forms. Data included patient disease characteristics, patient risk status (APACHE scores), type of fluconazole therapy, drug-related adverse events, length of fluconazole therapy, and length of hospital stay. Switches in fluconazole therapy, dosing changes, additional concomitant antifungal therapy, overall mor- tality, and clinical outcomes were also evaluated. Logistic regres- sion models determined univariate and multivariate associations with mortality. Results T. gondii IgG antibodies were positive in 56.3% of ICU patients (n = 58) and in 24.3% of healthy volunteers (n = 19) (P < 0.031). IgM antibodies were positive in 13.8% of ICU patients (n = 15) and in 6.4% of healthy volunteers (n = 5); however, this difference could not reach statistical significance. Conclusion The results of the study reveal that toxoplasma seropositivity is not uncommon in ICU patients. Therefore, to prevent the possibility of toxoplasmosis, seropositivity should be periodically assessed in critically ill immunocompromised ICU patients. It is clear that further studies are required to evaluate the effects of seropositivity on ICU outcome. P115 Consequences of cytomegalovirus reactivation in patients with severe sepsis P112 Patients with gastrointestinal surgery were at risk for development of early fungal sepsis – by the 10th day of admission – compared with the other clinical cases – by the 21st day of admission. The incidence rate of positive blood cultures for Candida in the group exposed to our scheme was calculated as 6.7% vs 18.5% in the control group. Conclusion C. albicans is the most common fungal pathogen in our ICU. Seven percent of colonized patients developed candidemia. Major postoperative complications, excessive antibiotic exposure and acute renal failure seem to predispose to the development of candidemia. Patients with candidemia have high inhospital mortality, perhaps as a reflection of illness severity. S44 Available online http://ccforum.com/supplements/11/S2 The role of plasminogen activator inhibitor 1 measurement with endotoxin adsorption therapy (PMX-DHP) for postoperative septic shock patients The role of plasminogen activator inhibitor 1 measurement with endotoxin adsorption therapy (PMX-DHP) for postoperative septic shock patients T Ikeda, K Ikeda, Y Kuroki, T Yokoyama, K Yoshikawa Tokyo Medical University, Hachioji Medical Center, Tokyo, Japan Critical Care 2007, 11(Suppl 2):P116 (doi: 10.1186/cc5276) Patients and methods We treated 27 septic shock patients using DHP-PMX. The patients were separated into two groups for analysis: those whose systolic blood pressure (SBP) increased by more than 30 mmHg immediately after DHP-PMX (15 cases), and those whose SBP did not increase by more than 30 mmHg after DHP-PMX (12 cases). Furthermore, the patients were separated into two other groups for analysis: those whose P/F ratio increased by more than 20% immediately after DHP-PMX (15 cases), and those whose P/F ratio did not increase by more 20% after DHP- PMX (12 cases). Mediators were measured at four points: before and after DHP-PMX, and 1 day and 3 days afterward. Introduction A polymyxin B immobilized fiber column (PMX; Toray Industries Inc., Tokyo, Japan) was developed in Japan in 1994 and it has been used for treatment of endotoxemia or septic shock patients. Materials and methods All patients received an urgent operation due to intra-abdominal infection. In 88 cases treated with a poly- myxin B immobilized column through direct hemoperfusion (PMX- DHP), changes in hemodynamics, pulmonary oxygenation (PaO2/ FIO2) and various mediators (IL-6, IL-8, IL-ra, plasminogen activator inhibitor 1 (PAI-1)) were examined before and after PMX-DHP, stratifying with the outcome (64 survivors and 24 who died). PMX- DHP was performed through a double lumen catheter (11.5 Fr), placed in the femoral vein or internal jugular vein, at a blood flow rate of 80 ml/min using nafamostat mesilate as an anticoagulant for 2 hours. Results The patient group consisted of 17 males and 10 females, 59.6 ± 12.7 years old. The average APACHE II score was 27.2 ± 9.1, and the average SOFA score was 11.7 ± 5.2 before DHP-PMX. Nineteen patients survived and eight died. When the changes in PAI-1, protein C, ATIII, IL-6 and high mobility group box protein 1 (HMGB-1) were compared between the groups, only the HMGB-1 levels had improved significantly in the SBP increased group (P = 0.0125). The SBP increased significantly after DHP- PMX in the HMGB-1-improved group (P < 0.0001). An improve- ment in the P/F ratio and a reduction in 2-arachidonoyl glycerol during DHP-PMX were significantly correlated (P = 0.0184). P117 increased mortality in CMV+ patients, although CMV disease did not occur. There was a striking difference between the groups in respect to the period on ventilator: 21.5 days vs 8.0 days (median) in CMV+ and CMV– patients, respectively (P < 0.005). Similarly, CMV+ patients had a longer median LOS after enrollment either in the ICU (29.5 days vs 10 days, P < 0.001) and in the hospital (49 days vs 23 days, P < 0.001). This difference was assured when the analysis was restricted to survivors. Mechanism and effectiveness of polymyxin B-immobilized fiber columns for removing mediators (HMBG-1, 2-arachidonoyl glycerol, anandamide, PAI-1, protein C and IL-6) in septic shock patients Y Sakamoto1, K Mashiko1, T Obata2, Y Yamamoto3 1Chiba Hokusou Hospital, Nippon Medical School, Chiba, Japan; 2Institute of DNA Medicine, Jikei University School of Medicine, Tokyo, Japan; 3Department of Emergency Medicine, Nippon Medical School, Tokyo, Japan Critical Care 2007, 11(Suppl 2):P117 (doi: 10.1186/cc5277) Mechanism and effectiveness of polymyxin B-immobilized fiber columns for removing mediators (HMBG-1, 2-arachidonoyl glycerol, anandamide, PAI-1, protein C and IL-6) in septic shock patients Mechanism and effectiveness of polymyxin B-immobilized fiber columns for removing mediators (HMBG-1, fiber columns for removing mediators (HMBG-1, 2-arachidonoyl glycerol, anandamide, PAI-1, protein C and IL-6) in septic shock patients Y Sakamoto1, K Mashiko1, T Obata2, Y Yamamoto3 1Chiba Hokusou Hospital, Nippon Medical School, Chiba, Japan; 2Institute of DNA Medicine, Jikei University School of Medicine, Tokyo, Japan; 3Department of Emergency Medicine, Nippon Medical School, Tokyo, Japan Critical Care 2007, 11(Suppl 2):P117 (doi: 10.1186/cc5277) Conclusion Our data suggest that CMV reactivation leads to increased morbidity and treatment expenditure independently from CMV disease. Further analysis points at a crucial role of lung pathology due to CMV reactivation. The role of plasminogen activator inhibitor 1 measurement with endotoxin adsorption therapy (PMX-DHP) for postoperative septic shock patients Results PMX-DHP significantly increased systemic arterial pressure and mean arterial pressure, with a greater increase in the survival group. Also, there appeared to be a trend for PaO2/FIO2 improve- ment as blood pressure increased. As the mechanism for improve- ment of pulmonary oxygenation by PMX-DHP has not been shown clearly, it remained to be examined further. PAI-1 values significantly decreased in the survivor group (from 436 ± 549 to 251 ± 283 ng/ml) immediately after PMX-DHP; also intracellular adhesion molecule-1 and endothelial leukocyte adhesion molecule- 1 tended to decrease in both groups. Conclusion We showed that the circulation dynamics of septic shock patients can be improved by reducing HMGB-1 levels and that respiratory function can be improved by reducing 2- arachidonoyl glycerol levels using DHP-PMX. P114 Seropositivity incidence of anti-Toxoplasma gondii antibodies in critically ill intensive care unit patients Seropositivity incidence of anti-Toxoplasma gondii antibodies in critically ill intensive care unit patients ÖS Can, S Yalçin, O Memikoglu, E Özgencil, S Oba, M Tulunay, N Ünal, M Oral Ankara University Medical Faculty, Ankara, Turkey Critical Care 2007, 11(Suppl 2):P114 (doi: 10.1186/cc5274) Results CMV reactivation was observed in 38 out of 99 patients. Both groups (CMV+/CMV– patients) were quite similar in regard to gender and age at study enrollment. Interestingly, the median SAPS II was higher in CMV– patients (47 vs 42; P < 0.013). Accordingly, a lower mortality rate was anticipated for CMV+ patients compared with the CMV– group. Contrary to expectations, mortality did not differ between both groups (CMV+ 36.8% vs CMV– 42.6%; P > 0.67). This may point to a relatively Introduction Toxoplasma gondii, a worldwide-distributed parasite, could cause opportunistic infection with high mortality in immuno- suppressive individuals. Its association with severe manifestations of immunosuppression has been known for several decades, and the occurrence of encephalitis and disseminated disease has since been observed in different clinical conditions such as lympho- Introduction Toxoplasma gondii, a worldwide-distributed parasite, could cause opportunistic infection with high mortality in immuno- suppressive individuals. Its association with severe manifestations of immunosuppression has been known for several decades, and the occurrence of encephalitis and disseminated disease has since been observed in different clinical conditions such as lympho- S45 S Livigni1, D Silengo1, M Maio1, V Perlo1, M Pozzato1, P Selvaggi1, L Sereni1,2, M Wratten2 1San Giovanni Bosco, Turin, Italy; 2Bellco, Mirandola, Italy Critical Care 2007, 11(Suppl 2):P118 (doi: 10.1186/cc5278) P116 Introduction Septic shock remains a major cause of multiple organ failure with a high mortality rate. To remove an endotoxin in patient plasma, direct hemoperfusion (DHP) using a polymyxin B- immobilized fiber column (PMX; Toray Industries Inc., Tokyo Japan) was developed in Japan in 1994 and has since been used for the treatment of septic shock. The precise role of PMX is not clear. P118 Discussion PAI-1 is elevated by endotoxin, thrombin and cytokines, and is an indicator of vascular endothelial cell activation. In septic dissminated intravascular coagulation from Gram-nega- tive bacilli, a massive amount of PAI-1 is produced on vascular endothelial cells along with elevation of cytokine production and coagulation activity. In addition, PAI-1, one of the fibrinolysis inhibitory factors, plays an important role in regulating fibrinolysis by inhibiting tissue plasminogen activator, which converts plasminogen to active plasmin on fibrin, to block unnecessary fibrinolysis. Characterization of the coupled plasma filtration–adsorption resin cartridge adsorptive capacity for cytokines and inflammatory mediators: adsorption profiles from septic patient plasma and in vitro endotoxin- stimulated whole blood S Livigni1, D Silengo1, M Maio1, V Perlo1, M Pozzato1, P Selvaggi1, L Sereni1,2, M Wratten2 1San Giovanni Bosco, Turin, Italy; 2Bellco, Mirandola, Italy Critical Care 2007, 11(Suppl 2):P118 (doi: 10.1186/cc5278) Conclusion The determination of PAI-1 may be a useful clinical parameter for predicting PMX-DHP efficacy. Introduction Coupled plasma filtration–adsorption (CPFA) is an extracorporeal therapy that uses plasma filtration associated with an adsorbent cartridge and hemofiltration in postdilution to remove cytokines and inflammatory mediators associated with septic shock and severe sepsis. We evaluated the adsorptive capacity of the resin cartridge to remove various inflammatory mediators and cyto- kines in vitro and ex vivo. Introduction Coupled plasma filtration–adsorption (CPFA) is an extracorporeal therapy that uses plasma filtration associated with an adsorbent cartridge and hemofiltration in postdilution to remove cytokines and inflammatory mediators associated with septic shock and severe sepsis. We evaluated the adsorptive capacity of the resin cartridge to remove various inflammatory mediators and cyto- kines in vitro and ex vivo. S46 Available online http://ccforum.com/supplements/11/S2 Figure 1 (abstract P119) Figure 2 (abstract P119) Figure 1 (abstract P119) Figure 2 (abstract P119) Figure 1 (abstract P119) Methods In vitro experiments included static and dynamic evaluations of resin binding. Whole human blood was stimulated with endotoxin for 4 hours at 37°C; or with the addition of added cytokines or toxins for evaluation. For static conditions, 4 ml plasma with 1 ml resin were incubated for up to 10 hours. Aliquots were withdrawn between 0 and 10 hours and cytokine inflammatory mediator and toxin adsorption were determined with standard ELISAs, multianalyte protein arrays, HPLC and diode array adsorption spectroscopy. Dynamic conditions involved defining the optimal linear velocity and evaluating the adsorption capacity under flow conditions. P118 These experiments used a closed circuit consisting of a plasma filter and resin cartridge. Samples were taken from a blood port and immediately before and after the plasma cartridge. In addition, serum, pre-cartridge and post- cartridge plasma samples were also taken from septic patients undergoing CPFA. Results Endotoxin-stimulated blood or samples from septic patients had high levels of cytokines and inflammatory mediators. The resin used in the CPFA adsorptive cartridge showed higher than 80% adsorption under both static and dynamic conditions for: IL-1α, IL-6, IL-8, MIP-1α and MIP-1β, TNFα, MCP, myoglobin. IL-6 appeared to be particularly adsorbed by the cartridge. Severe septic patients had great variability and often very high levels of IL-6 ranging from normal levels (50 pg/ml) up to 12,300 pg/ml. The mean of 10 patients treated before CPFA was 1,775 ± 3757 pg/ml, while post- session IL-6 was 995 ± 2178 pg/ml. The plasma levels before the cartridge ranged from 12 pg/ml to 1,750 pg/ml, while post- cartridge levels were below the level of detection. Figure 2 (abstract P119) Conclusions The resin in CPFA has a high adsorption capacity for several cytokines and mediators involved in severe sepsis and septic shock. Studies are currently ongoing to correlate cytokine reduction with clinically relevant improvements in these patients. P119 Removing endocannabinoids and reducing oxidative stress with polymyxin-B-immobilized fibers in patients with septic shock Y Kase, T Obata Jikei University Hospital, Tokyo, Japan Critical Care 2007, 11(Suppl 2):P119 (doi: 10.1186/cc5279) Y Kase, T Obata Jikei University Hospital, Tokyo, Japan Critical Care 2007, 11(Suppl 2):P119 (doi: 10.1186/cc5279) Introduction Arachidonylethanolamide (AEA) and 2-arachidonyl- glycerol (2-AG) are endocannabinoids involved in septic shock, and 8-epi prostaglandin F2α (F2-isoprostane) is a biomarker of oxidative stress. Because the antibiotic polymyxin-B binds to endotoxins and endocannabinoids, direct hemoperfusion therapy with polymyxin-B-immobilized fibers (PMX-DHP) decreases serum levels of endocannabinoids. To investigate the features of sepsis and to determine the proper usage of PMX-DHP, we compared perioperative changes in levels of endocannabinoids and F2- isoprostane in patients with septic shock Conclusions Patients with septic shock are under considerable oxidative stress, and 2-AG plays an important role in the cardiovascular status of these patients. The removal of 2-AG by PMX-DHP benefits patients with septic shock by stabilizing cardiovascular status and decreasing long-term oxidative stress. Conclusions Patients with septic shock are under considerable oxidative stress, and 2-AG plays an important role in the cardiovascular status of these patients. The removal of 2-AG by PMX-DHP benefits patients with septic shock by stabilizing cardiovascular status and decreasing long-term oxidative stress. P121 The effectiveness of octreotide at different doses for sulfonylurea-induced hypoglycemia following overdose M Gul, B Cander, S Girisgin, M Ayan, S Kocak, A Unlu Selcuk University Meram Medical School, Konya, Turkey Critical Care 2007, 11(Suppl 2):P121 (doi: 10.1186/cc5281) The effectiveness of octreotide at different doses for sulfonylurea-induced hypoglycemia following overdose M Gul, B Cander, S Girisgin, M Ayan, S Kocak, A Unlu Selcuk University Meram Medical School, Konya, Turkey Critical Care 2007, 11(Suppl 2):P121 (doi: 10.1186/cc5281) Results Forty patients admitted to the ICU were enrolled and followed up to discharge. The median age was 35.5 years (mini- mum 18, maximum 66). The median APACHE II score was 10.5 (minimum 2, maximum 28) and the median duration was 6 days (minimum 1, maximum 43). D0, D3, D7 and D/C glucose concen- trations did not differ (Kruskal–Wallis ANOVA, P = 0.98). TNFα peaked at D3 (4.9 pg/ml) and then started decreasing. Admini- stered insulin (InsAd) accompanied the TNFα peak at D3 (32U) and then decreased. Adipo peaked at D7 (10,774 pg/ml) after the TNFα peak, which coincided with the TNFα decrease at D7 to 4.76 pg/ml. Endogenous insulin indicated by CPep peaked with Adipo at D7 (2.8 µg/l). TG levels increased in parallel with increasing TNFα from 0.7 mmol/l at D0 to 1.1 mmol/l at D3 and then declined. TC was lowest at D0 and increased up to D/C but remained relatively low. Table 1 shows several variables and their change over time from admission to discharge. Table 2 shows the correlations between these variables. Survivors had a lower median TNF than nonsurvivors (Mann–Whitney U test, P = 0.066). Conclusion TNF contributes to increased insulin needs. TNF is known to cause insulin resistance. We have shown that TNF correlates inversely with Adipo. As Adipo increases, insulin needs are decreased (inverse correlation with InsAd). Also, TNF contributes to increase TG indicating increased free fatty acids (FFA) by lipolysis, which impairs glucose clearance. Adipo, an insulin sensitizing protein, is known to negatively regulate TNF levels as was indicated by our study. Adipo contributed to a decrease in TG indicating lower FFA and better glucose clearance. IL-6 at D/C also contributed to a higher glucose concentration at D/C. Increasing age contributed to lower Adipo levels at D/C, indicating lower insulin sensitivity. Cytokines associated with insulin resistance in critically ill patients Cytokines associated with insulin resistance in critically ill patients Methods Twenty-four patients with septic shock induced by peritonitis underwent laparotomy for drainage. Endocannabinoid absorption with PMX-DHP was examined in two groups of patients: patients in whom systolic arterial BP had increased more than 20 mmHg (BP elevation group; n = 12) and patients in whom BP did not increase or had increased no more than 20 mmHg (BP constant group; n = 12). S Omar, U Wilgen, N Crowther University of Witwatersrand, Gauteng, South Africa Critical Care 2007, 11(Suppl 2):P120 (doi: 10.1186/cc5280) Introduction We examined the relationship between proinflammatory cytokines, adipocyte-derived adiponectin and hyperglycemia. Patients requiring long periods in the ICU have a relatively high mortality. Tight glucose control with insulin infusions has been shown to improve survival and prevent complications. Methods A prospective, observational study at an academic ICU. A sequential sample was taken over a 2-month period. Ethics approval was obtained from the University Ethics Committee. Introduction We examined the relationship between proinflammatory cytokines, adipocyte-derived adiponectin and hyperglycemia. Patients requiring long periods in the ICU have a relatively high mortality. Tight glucose control with insulin infusions has been shown to improve survival and prevent complications. Introduction We examined the relationship between proinflammatory cytokines, adipocyte-derived adiponectin and hyperglycemia. Patients requiring long periods in the ICU have a relatively high mortality. Tight glucose control with insulin infusions has been shown to improve survival and prevent complications. Methods A prospective, observational study at an academic ICU. A sequential sample was taken over a 2-month period. Ethics approval was obtained from the University Ethics Committee. Results Levels of AEA did not change after PMX-DHP in the either the BP constant group or the BP elevation group, whereas levels of 2-AG decreased significantly after PMX-DHP in the BP elevation group but not in the BP constant group (Figure 1). F2-isoprostane gradually increased after PMX-DHP. On the other hand, levels of F2- isoprostane remained constant in the BP elevation group (Figure 2). Methods A prospective, observational study at an academic ICU. A sequential sample was taken over a 2-month period. Ethics approval was obtained from the University Ethics Committee. S47 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Baseline bloods for TNFα, IL-6, adiponectin (Adipo), total cholesterol (TC), triglycerides (TG), insulin, C-peptide (CPep) and cortisol (Cort) were collected on admission (D0). P121 A higher BMI contributed to a Objective The aim of the study was to investigate the effectiveness of octreotide at different doses in reducing the hypoglycemic attacks and the need for dextrose in treatment of refractory and recurrence hypoglycemia related to the toxicity of sulfonylurea. y y y y Methods In the study, 40 New Zealand type of rabbits were used weighing between 2,500 and 3,000 g. The rabbits were randomly divided into four groups consisting of 10 animals. All the animals were given gliclazide 100 mg orally. For the treatment of hypoglycemic attacks in Group I, only 15 cm3 50% dextrose (7.5 g) intravenously (i.v.) was used; in Group II, Group III and Group IV octreotide 25 µg, 50 µg and 100 µg single doses were used subcutaneously, respectively. Octreotide was given in Groups II and III and Group IV at the eighth hour (when hypoglycemic attacks onset). Groups II, III and IV were given an additional 15 cm3 50% dextrose (7.5 g) i.v. infusion for each hypoglycemic attack developed. Following the toxic dose, animals were given the amount of dextrose used before and after octreotide administration and the number of hypoglycemic attacks were recorded. Results There was a significant difference between Groups I, II, and IV in the number of hypoglycemic attacks and the number of dextrose requirement between 9 and 24 hours (P = 0.001). Groups receiving octreotide showed less hypoglycemic attacks and dextrose requirements than controls. Conclusion Our experience suggests that octreotide may be used to reduce the number of refractory and recurrence hypoglycemic attacks developing due to overdose of sulfonylurea; large prospective studies would be needed to validate these findings. Cytokines associated with insulin resistance in critically ill patients These were repeated on day 3 (D3), day 7 (D7) and discharge (D/C). Routine bloods ordered were also used. Data on the ICU charts were also used. No changes to ICU protocols were required. Of note, insulin infusions were started for blood glucose concentrations greater than 6 mmol/l. Exclusion criteria included all patients with diabetes mellitus, chronic renal failure and liver failure or cirrhosis. higher glucose level at D0 and increased insulin needs at D0. Finally, a higher TNF level appears to be related to increased mortality Influence of diabetes and HbA1c on the course and outcome of sepsis in the intensive care unit Methods PBMC were isolated from peripheral blood of 10 healthy volunteers via Ficoll gradient. Cells were incubated for 3 hours at 37°C with/without low/high concentrations of glucose, mannitol, urea, insulin and stimulated with 0.5 ng/ml LPS. After 24 hours, concentrations of IL-6 and IL-1β were measured with an ELISA method. I Gornik1, O Gornik2, V Gasparovic1 1Clinical Hospital Centre, Zagreb, Croatia; 2University of Zagreb, Croatia Critical Care 2007, 11(Suppl 2):P124 (doi: 10.1186/cc5284) Introduction It is an accepted opinion that patients with diabetes mellitus (DM) are at higher risk when treated for infections, although published data are lacking. Our recent research on non- ICU septic patients showed that admission HbA1c is in correlation with outcome. The aim was to evaluate the impact of DM on the course and outcome of patients with sepsis in ICU, as well as to evaluate the value of HbA1c as an outcome predictor in the ICU Results Increasing concentrations of glucose, mannitol and urea resulted in a significant increase of IL-6 and IL-1β cytokine production. Insulin had no effect (Table 1). Table 1 (abstract P122) No Low High Substance supplementation concentration concentration Glucose 1,726 – 9,643 Insulin 609 555 636 Urea 2,056 3,421 3,835 Mannitol 367 – 3,269 evaluate the value of HbA1c as an outcome predictor in the ICU. Methods In a prospective, 3-year observational study, patients with sepsis, severe sepsis and septic shock admitted to a medical ICU were included. Patients with DM were compared with nondiabetics in terms of course and outcome. HbA1c was measured for all patients with DM. Hospital mortality and length of stay (LOS) in the ICU and in hospital were the outcome measures. The incidence of organ failure, ARDS, hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) were used as indicators of the disease course. Nonparametric tests, multiple regression and logistic regression were used in statistical analyses. Conclusion High concentrations of glucose, mannitol and urea lead to a significant increase in IL-6 and IL-1β cytokine production by PBMC in vitro. The most profound effect was seen with hyperglycemia. Besides hyperglycemia, also uremia and high osmolarity seem to augment inflammation. Insulin could not reverse the increase in inflammation. These findings may be relevant in explaining the beneficial effects of normoglycemia on the inflammatory response in critically ill patients. Results Two hundred and twenty-nine patients with sepsis at admission (19.6% of all 1,169 ICU patients), 59 with DM, were included. Influence of diabetes and HbA1c on the course and outcome of sepsis in the intensive care unit Mortality in the ICU was 34.7%; the median ICU LOS was 8 (95% CI 7–9.3) days. Patient with DM, compared with nondiabetics, had higher mortality (38.9% vs 34.1%, P = 0.60) and longer ICU LOS (median 6 vs 10 days, P < 0.001), and higher incidence of renal failure, HAP, VAP. Surviving patients had significantly lower HbA1c levels (6.6 vs 9.6, P = 0.001). In a logistic regression, DM was found to be related to lethal outcome, together with APACHE II and SOFA scores. In multiple regression, DM related to LOS together with SOFA score and age. HbA1c was found to be independently related to ICU outcome together with SOFA score. P122 inflammatory mediator production can be modified by insulin therapy. Rats subjected to bacterial lipopolysaccharide (LPS) with or without insulin pretreatment were studied. LPS-induced PARP activation in circulating leukocytes was measured by flow cytometry, and production of TNFα was measured by ELISA. LPS induced a significant hyperglycemic response, activated PARP in circulating leukocytes and induced the production of TNFα. Insulin treatment prevented the LPS-induced hyperglycemic response, blocked the activation of PARP and blunted the LPS-induced TNFα response. As hyperglycemia is known to induce the cellular formation of reactive species, we propose that PARP activation in endotoxin shock occurs as a result of hyperglycemia-induced reactive oxidant and free radical generation. The current findings may have significant implications in the context of the emerging concept of tight glycemic control for critically ill patients. P122 Hyperglycemia and changes in osmolarity lead to an increase in IL-6 and IL-1β cytokine production of human peripheral blood mononuclear cells in vitro N Otto, R Schindler, U Frei, M Oppert Charité-Universitaetsmedizin Berlin, Germany Critical Care 2007, 11(Suppl 2):P122 (doi: 10.1186/cc5282) Hyperglycemia and changes in osmolarity lead to an increase in IL-6 and IL-1β cytokine production of human peripheral blood mononuclear cells in vitro Hyperglycemia and changes in osmolarity lead to an increase in IL-6 and IL-1β cytokine production of human peripheral blood mononuclear cells in vitro N Otto, R Schindler, U Frei, M Oppert Charité-Universitaetsmedizin Berlin, Germany Critical Care 2007, 11(Suppl 2):P122 (doi: 10.1186/cc5282) Introduction Acute hyperglycemia and insulin resistance are characteristics of metabolic and endocrine imbalances of critically ill patients and are subject to a substantial inflammatory response that is partly mediated by cytokines produced by peripheral blood mononuclear cells (PBMC). Treatment with intensive insulin therapy to keep patients normoglycemic has been shown to reduce inflammatory responses. It is unclear whether hyper- glycemia, insulin or osmolarity changes exert direct effects on proinflammatory cytokines. We investigated the direct effects of these substances on cytokine production of PBMC in vitro. Table 1 (abstract P120) Changes in glucose, insulin, cytokines and lipids in the ICU over time Day Glucose InsAd TNF Adipo Cpep TG TC IL-6 D0 6.13 8 3.49 4,413.82 1.8 0.7 2.15 337.01 D3 6.25 32 4.9 6,925.4 2.2 1.1 2.2 127.01 D7 6.79 20 4.76 10,774.25 2.8 1 2.5 32.17 D/C 5.87 0 4.11 8,288.6 2.5 1.3 2.8 46.95 Table 2 (abstract P120) Relevant Spearman correlations between the parameters A B R P A B R P TNF Adipo –0.59 0.000 TNF Mortality 0.25 0.060 Adipo InsAd –0.46 0.005 ∆Adipo LOS 0.45 0.004 TNF TG 0.74 0.000 IL-6 D/C Gluc D/C 0.34 0.042 Adipo TG –0.41 0.001 BMI Gluc D0 0.39 0.012 TNF Cortisol –0.73 0.000 BMI InsAd D0 0.31 0.053 Adipo Cortisol 0.51 0.000 Adipo D/C Age –0.35 0.030 Age InsAd D/C 0.35 0.032 Changes in glucose, insulin, cytokines and lipids in the ICU over time elevant Spearman correlations between the parameters S48 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 P125 Lipid metabolism and organ dysfunction in septic patients during intensive glycemic control S Cappi, F Soriano, A Nogueira, C Valeri, A Duarte, P Biselli, W Hoshino, M Lins, J Barradas, D Noritomi, P Lotufo Hospital Universitario da USP, Sao Paulo, Brazil Critical Care 2007, 11(Suppl 2):P125 (doi: 10.1186/cc5285) Introduction Intensive glycemic control has been widely discussed in critical care patients. It remains unclear whether intensive insulin therapy also improves the prognosis of patients in a medical ICU, who often are more severely ill than are patients in a surgical ICU and have a higher risk of death. Recently, medical patients have been investigated, as a special group. We decided to study possible differences in lipid profile in septic shock patients during the first 72 hours and correlate it with different organ dysfunctions. Methods A prospective, randomized, controlled study in a 12-bed medico-surgical ICU in a university hospital. Inclusion criteria: all consecutive patients admitted to the ICU with severe sepsis and or septic shock with onset in a maximum of 24 hours. Exclusion criteria: HIV patients, pregnancy, diagnosis of leptospirosis, age under 18, cancer patients. On admission, patients were randomly assigned to strict normalization of blood glucose levels (80–110 mg/dl) or to a conventional glycemic control (180–220 mg/dl) with the use of sealed envelopes. We collected laboratory tests at 0, 24, 48 and 72 hours after initiation. For statistical analysis we per- formed the Student t test. R l W di d i i h i il d hi d g y Methods A prospective, randomized, controlled study in a 12-bed medico-surgical ICU in a university hospital. Inclusion criteria: all consecutive patients admitted to the ICU with severe sepsis and or septic shock with onset in a maximum of 24 hours. Exclusion criteria: HIV patients, pregnancy, diagnosis of leptospirosis, age under 18, cancer patients. On admission, patients were randomly assigned to strict normalization of blood glucose levels (80–110 mg/dl) or to a conventional glycemic control (180–220 mg/dl) with the use of sealed envelopes. We collected laboratory tests at 0, 24, 48 and 72 hours after initiation. For statistical analysis we per- formed the Student t test. and HDL (not significant) were different between groups. The mortality rate was the same but LDL and HDL had negative correlation with organ function among nonsurvivors. Insulin therapy inhibits poly(ADP-ribose)polymerase activation in endotoxin shock C Szabo1, E Horvath1, R Benko2, D Gero2 1University of Medicine and Dentistry of New Jersey, Newark, NJ, USA; 2Semmelweis University, Budapest, Hungary Critical Care 2007, 11(Suppl 2):P123 (doi: 10.1186/cc5283) Conclusion The ratio of patients with DM among ICU patients with sepsis exceeds greatly the incidence of DM in the population. This emphasizes the risk they have. DM was associated with worse outcome, longer ICU and hospital LOS, and with higher incidence of complications. HbA1c was confirmed as an outcome predictor for ICU patients. The nuclear enzyme poly(ADP-ribose) polymerase (PARP) is activated in various forms of circulatory shock. By triggering a cellular energetic dysfunction, and by promoting proinflammatory gene expression, PARP activation significantly contributes to the pathogenesis of shock. The activation of PARP is usually triggered by DNA strand breakage, which is typically the result of the overproduction of reactive oxidant species. In the present study we tested whether endotoxin-induced PARP activation and pro- S49 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine Figure 2 (abstract P125) Figure 2 (abstract P125) P125 Lipid metabolism and organ dysfunction in septic patients during intensive glycemic control S Cappi, F Soriano, A Nogueira, C Valeri, A Duarte, P Biselli, W Hoshino, M Lins, J Barradas, D Noritomi, P Lotufo Hospital Universitario da USP, Sao Paulo, Brazil Critical Care 2007, 11(Suppl 2):P125 (doi: 10.1186/cc5285) P125 Lipid metabolism and organ dysfunction in septic patients during intensive glycemic control Conclusions Targeting blood glucose levels to below 110 mg/dl with insulin therapy prevented morbidity, probably due to a better control of lipid metabolism, expressed as a more rapid serum LDL normalization and avoiding a greater decrease in serum HDL levels in the first 72 hours of septic shock. Results We studied 58 patients with similar demographic data between the two groups. The increases in serum LDL (P < 0.05) 0 Figure 1 (abstract P125) Figure 1 (abstract P125) P127 Variable adsorption of insulin at catheter materials used in intensive care units: polyethylene vs polyurethane – possible cause for hypoglycemia during intensive insulin p yp g y g treatment? Methods A retrospective observational cohort study was conduc- ted including 130 adult patients with a microbiologically documented BSI admitted over a 2-year period (2003–2004) to the ICU. Blood glucose levels were evaluated from 1 day prior to onset of BSI (d–1) until 5 days after onset of BSI (d+5). The contribution of hyperglycemia, divided into three subgroups (≥150 mg/dl, ≥175 mg/dl, and ≥200 mg/dl, respectively), to in- hospital mortality was estimated by logistic regression. S Ley, J Ammann, C Herder, M Hartmann, D Kindgen-Milles University Hospital, Duesseldorf, Germany Critical Care 2007, 11(Suppl 2):P127 (doi: 10.1186/cc5287) Introduction Intensive insulin therapy reduces morbidity and mortality in postoperative critical care; however, this treatment also increases the risk of hypoglycemia. A possible cause for unstable blood glucose (BG) levels could be a variable adsorption of insulin at plastic material of infusion tubings. We evaluated in vitro and in vivo the adsorption of insulin at standard tubing materials (polyethylene (PE) and polyurethane (PU)) and the effects of this adsorption process on blood glucose levels. Results The mean age of the study population was 54.7 ± 19.0 years. Inhospital mortality was 36.2%. Hyperglycemia (≥175 mg/dl and ≥200 mg/dl) was observed more often among the non- survivors. Over the seven study days, no differences were found in daily morning blood glucose levels between survivors (n = 83) and nonsurvivors (n = 47) (all P > 0.05). Although in the nonsurvivors the evolution of glycemia tended to be higher, this trend was not statistically significant compared with the survivors. Multivariate logistic regression revealed that age (P = 0.022), APACHE II score (P = 0.003), antibiotic resistance (P = 0.001), and hyperglycemia (≥200 mg/dl) upon onset of BSI (P = 0.001) were independently associated with inhospital mortality, whereas appropriate anti- microbial therapy ≤24 hours (P = 0.016) and previous history of diabetes (P = 0.022) were associated with better outcome. Methods (1) In vitro, a standard perfusor syringe (Perfusor®; BBraun, Germany) was filled with 50 IE normal insulin (Actrapid®; NovoNordisk, Germany) dissolved in 50 ml saline 0.9%. P128 Hyperglycemia upon onset of nosocomial bloodstream infection adversely affects outcome in a mixed intensive care unit population Hyperglycemia upon onset of nosocomial bloodstream infection adversely affects outcome in a mixed intensive care unit population These findings indicate that the coagulation system did not play a key role in mediating the survival benefit of intensive insulin therapy. References D Vandijck, S Oeyen, F Buyle, B Claus, S Blot, J Decruyenaere Ghent University Hospital, Ghent, Belgium Critical Care 2007, 11(Suppl 2):P128 (doi: 10.1186/cc5288) 1. Van den Berghe G, et al.: N Engl J Med 2001, 345:1359- 1367. 2. Van den Berghe G, et al.: N Engl J Med 2006, 354:449-461. Introduction Hyperglycemia in critically ill patients is frequently related to a hypermetabolic stress-response and has been associated with increased morbidity and mortality. The aim of this study was to assess the relationship between blood glucose levels and clinical outcome in a mixed cohort of critically ill patients with a nosocomial bloodstream infection (BSI). P127 The syringe was connected to PE or PU tubings (BBraun) and, at an infusion rate of 1 ml/hour, the insulin concentration in the syringe and at the end of the tubings was measured at hourly intervals for 5 hours and again after 24 hours by the Bradford protein assay. Insulin concentrations were compared using the Student t test. (2) In a prospective, double-blinded, cross-over study, approved by the ethics committee, 10 patients on the surgical ICU received insulin via PE or PU tubing each for 24 hours in random sequence. All blood BG values, total infused insulin solution volume, and critical care scores were documented and statistically analysed by the Wilcoxon test. Conclusion Trends of blood glucose levels were higher among nonsurvivors. Hyperglycemia (≥200 mg/dl) upon onset of nosocomial BSI adversely affects outcome in a heterogeneous ICU population. Effect of intensive insulin therapy on coagulation and fibrinolysis of respiratory critically ill patients L Langouche1, W Meersseman1, S Van der Perre1, I Milants1, P Wouters1, G Hermans1, J Gjedsted2, T Hansen2, J Arnout1, A Wilmer1, M Schetz1, G Van den Berghe1 1KU Leuven, Belgium; 2Aarhus University Hospital, Aarhus, Denmark Critical Care 2007, 11(Suppl 2):P126 (doi: 10.1186/cc5286) Most intensive care deaths beyond the first few days of critical illness are attributable to nonresolving multiple organ failure (MOF), either due to or coinciding with sepsis. One of the mechanisms that is thought to contribute to the pathogenesis of MOF is microvascular thrombosis. Recently, we reported improved survival and prevention of MOF of critically ill patients with the use of intensive insulin therapy to maintain normoglycemia for at least several days [1,2]. We hypothesize that intensive insulin therapy also prevents severe coagulation abnormalities, thereby contribu- ting to less organ failure and better survival. We studied a subgroup of long-stay critically ill patients with a respiratory disease upon ICU admission, who had been enrolled in a randomized controlled trial evaluating the impact of intensive insulin therapy in medical ICU patients [2]. Plasma samples were analyzed for a panel of coagulation markers (prothrombin time, activated partial thromboplastin time, fibrinogen and D-dimer levels) that were used to assign points towards the International Society of Thrombosis and Haemostasis overt disseminate intravascular coagulation (DIC) score. Circulating plasma thrombin–antithrombin complexes and plasminogen inhibitor type 1 levels were also determined. As markers of inflammation, we measured circulating serum levels of several cytokines and CRP. S50 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Mortality of intensive insulin-treated patients was lower than of conventionally treated patients for all classes of upon-admission DIC score, except for those patients with a DIC score of 6 or higher. There was no effect of insulin therapy on any of the fibrinolytic, coagulation or inflammatory parameters tested. The accuracy of the DIC score to predict mortality in this patient sample was only moderate and comparable with that of CRP and the SOFA score. Also, circulating plasminogen inhibitor type 1 or thrombin–antithrombin complexes levels did not correlate well with mortality or DIC score. insulin application to the patient is possible if different tubing materials are used. Furthermore, variability of adsorption, a competitive adsorption with other drugs if insulin is not infused via a single line as well as changes of effective insulin application following routine change of tubings, may be one cause of unexpected hypoglycemia that can be deleterious to the patient. R Schaller1, F Feichtner1, A Fercher1, L Schaupp1, M Bodenlenz1, H Köhler1, J Plank2, A Wutte2, M Ellmerer3, R Hainisch4, T Pieber2 1Joanneum Research, Graz, Austria; 2Medical University Graz, Austria; 3Medical University Hospital (MUG), Graz, Austria; 4FH OÖ Forschungs & Entwicklungs GmbH, Linz, Austria Critical Care 2007, 11(Suppl 2):P129 (doi: 10.1186/cc5289) P129 Hence the usage of an automated discontinuous venous blood sampling system might be an alternative to improve the adjustment of the insulin therapy. The primary aim of the study was to investigate whether the glucose concentration in manually withdrawn blood samples correlates with automated withdrawn blood samples. Methods In a 12-hour trial, six volunteers were investigated (male/ female 5/1; age 28.2 ± 2.2 years, BMI 22.5 ± 1.3, nondiabetics). A 75 g OGTT was performed to enable a better dynamic range of the glucose values. Two venous cannulae were inserted into the dorsal hands for reference measurement and for connection to the automated blood sampling system. To reduce the volunteer’s health risk, pressure, air bubble sensor and flushing fluid monitor- ing were integrated into the system. Blood samples were obtained frequently in 15/30-minute intervals. Roche Microsamplers and the OMNI S6 glucose analyser were used for determination of the blood readings. Discussion Computerised decision-support and more intensive monitoring did not improve BG control or reduce the incidence of hypoglycaemia. Glargine insulin: an alternative to regular insulin for glycemic control in critically ill patients Glargine insulin: an alternative to regular insulin for glycemic control in critically ill patients M Bhattacharyya, SK Todi, A Majumdar AMRI Hospitals, Kolkata, India Critical Care 2007, 11(Suppl 2):P131 (doi: 10.1186/cc5291) Results The automated blood sampling system performed its operation in all volunteers over the whole trial period. The median Pearson coefficient of correlation between manual and automated withdrawn blood was 0.983 (0.862–0.995). Furthermore, the results (173 data pairs) were analysed via the recently published ‘Insulin Titration Error Grid Analysis’ and 99.4% were suggesting an acceptable treatment. The results of the traditional ‘Error Grid Analysis’ showed that 96% of the data were in zone A and 4% in zone B. Introduction The objective of this study was to determine the efficacy and safety of subcutaneous (s.c.) once-daily (OD) glargine insulin, a long-acting insulin, in comparison with a s.c. regular insulin, based on a protocolized sliding scale regimen for achieving glycemic control in patients admitted to the ICU. Methods One hundred patients admitted to the ICU with an admission capillary blood glucose (CBG) >150 mg/dl (8.3 mmol/l) were involved in this prospective, randomized study. Patients with age <18 years, pregnancy, shock, requiring continuous intra- venous insulin infusion, renal failure were excluded. Patients were randomly assigned to receive either s.c. glargine insulin 10 U (CBG ≤9.9 mmol/l) or 18 U (CBG ≥10.1 mmol/l) s.c. OD (Group G, n = 50), or s.c. regular insulin based on a 6-hourly sliding scale (Group R, n = 50). CBGs were recorded at 6-hour intervals up to 96 hours or until ICU discharge, whichever was earlier. The target CBG in both groups was <150 mg/dl (8.3 mmol/l). Patients in group G received rescue doses of regular insulin, as required. Demographic characteristics, mean and median CBG, and episodes of hypoglycemia were studied. Conclusion The automated discontinuous blood withdrawing system provides reproducible blood samples from peripheral venous blood. In combination with a glucose sensor and an algorithm it might be used in future as a closed loop system for insulin and glucose infusion at the ICU. P129 Results (1) The insulin concentration in all syringes was always >97% of the estimated value. The initial concentrations of insulin at the end of PE and PU tubings were lower than expected (23 ± 4% of anticipated concentration in the first 6 min). In PE, the concentration rose to 37 ± 2% and in PU to 78 ± 4% after 24 hours (P < 0.0001). (2) In vivo the mean BG values did not differ between PE and PU (PE 141 ± 17 mg/dl; PU 132 ± 23 mg/dl (not significant)). Severity of illness was not different between the groups: TISS 37 ± 5 (PE) vs 39 ± 5 (PU), SAPS 43 ± 13 (PE) vs 41 ± 15 (PU) on both days; neither were catecholamine doses and 24-hour fluid balance. However, significantly more insulin solution was infused in PE (66 ± 18 ml/ 24 hours) compared with PU (44 ± 15 ml/24 hours) (P = 0.0015). Conclusion Infusion of insulin using PE and PU tubings leads to a relevant adsorption of the drug in both materials. Adsorption to PE is significantly higher compared with PU. Thus, a large variation of System for automated discontinuous venous blood withdrawal for glucose determination of patients in the intensive care unit Introduction Intensive insulin therapy to establish normoglycaemia reduces mortality and morbidity in critically ill patients. Frequent glucose monitoring is restricted in critically ill patients due to the Introduction Intensive insulin therapy to establish normoglycaemia reduces mortality and morbidity in critically ill patients. Frequent glucose monitoring is restricted in critically ill patients due to the S51 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin 0.78 tests/hour) than the CIT group (3,609 over 8,617 hours, 0.42 tests/hour). The median (interquartile range (IQR)) proportion of time spent in the target range 4.4–6.1 mmol/l was similar in the IIT and CIT groups (23.21% (15.4–29.8) vs 17.9% (9.8–29.3), respectively; P = 0.17). Similarly, time spent with a BG between 6.2 and 7.99 mmol/l was no different for the two groups (48.5% (IQR 36.9–59.3) for IIT and 43.9% (IQR 34.7–60.9), P = 0.72). In the IIT and CIT groups, five and six patients experienced a BG below 2.2 mmol/l, respectively. high workload that has to be performed by the staff. Investigation of insulin clearance in severely acutely ill patients with glucose intolerance evaluated by means of bedside-type artificial pancreas Investigation of insulin clearance in severely acutely ill patients with glucose intolerance evaluated by means of bedside-type artificial pancreas M Hoshino1, Y Haraguchi2, I Mizushima1 1Tokyo Police Hospital, Tokyo, Japan; 2National Hospital Organization Disaster Medical Center, Tokyo, Japan Critical Care 2007, 11(Suppl 2):P132 (doi: 10.1186/cc5292) Background and purpose Glucose intolerance in acutely ill patients is one of the risk factors of their morbidity and mortality, and glucose control with insulin therapy improves the outcome. We investigated relationships among insulin clearance (IC), which is considered to be one of the factors related to effectiveness of insulin therapy, and glucose tolerance, glucose intolerance, and severity of the diseases, in order to clarify the significance of IC on the severity of the diseases including glucose intolerance and on the therapies. Background and purpose Glucose intolerance in acutely ill patients is one of the risk factors of their morbidity and mortality, and glucose control with insulin therapy improves the outcome. We investigated relationships among insulin clearance (IC), which is considered to be one of the factors related to effectiveness of insulin therapy, and glucose tolerance, glucose intolerance, and severity of the diseases, in order to clarify the significance of IC on the severity of the diseases including glucose intolerance and on the therapies. Methods Prospective collection of all glucose measurements for ICU patients receiving an insulin infusion protocol between 20 May 2006 and 6 August 2006 in 64 ICU beds at a teaching hospital. We report glucose values from all ICU patients, ≥8 hours after infusion initiation. Materials and methods Twenty-three ICU patients with glucose intolerance in whom strict blood glucose control was performed by means of a bedside-type artificial pancreas (NIKKISO Corp., Japan) were investigated. The diabetics were excluded. The items investigated were IC (ml/kg/min) measured by the glucose clamp method, daily mean blood glucose level as a parameter of glucose intolerance (BGm, mg/dl), proportion of septic patients (%), SOFA score and mortality (%) as indicators of the severity of the diseases, and blood concentration of free fatty acid (FFA) and stress hormones (glucagon, growth hormone, cortisol, adrenalin, noradrenalin) as factors that might affect glucose intolerance. Evaluation of the clinical effectiveness of a computerised decision-supported intensive insulin therapy regimen R Shulman, N Shah, P Glynne, R Greene, SJ Finney University College Hospital, London, UK Critical Care 2007, 11(Suppl 2):P130 (doi: 10.1186/cc5290) Introduction It has been proposed that intensive insulin therapy (IIT) aiming for a blood glucose (BG) of 4.4–6.1 mmol/l reduces mortality in critically ill patients when compared with conventional insulin therapy (CIT) targeting BG at 10.0–11.1 mmol/l. Difficulties with IIT include inadvertent hypoglycaemia and low efficacy at achieving the target BG. We proposed that computerised decision support may mitigate these problems. Results Demographic profiles were comparable between the two groups. There was no significant difference in mean CBG in both groups (Group G 152.1 mg/dl (8.4 mmol/l), Group R 149.9 mg/dl (8.3 mmol/l), P = 0.66). Median CBGs were comparable at 6- hourly time points in both the groups except at 0 and 6 hours in the glargine arm (CBG at 0 and 6 hours, Group G 10.0 mmol/l and Figure 1 (abstract P131) Objective To comprehensively describe BG and outcome from decision-supported IIT. Median capillary blood glucose (CBG) at different time points. Methods A clinical information system at each bedspace guided staff through the IIT algorithm. The time spent within glucose ranges was calculated assuming a linear trend between successive measurements. Results Patient characteristics are shown in Table 1. The IIT group had more frequent BG evaluation (7,007 over 8,944 patient-hours, 52 Table 1 (abstract P130) IIT (n = 50) CIT (n = 50) P value LOS, median (IQR) 7 (3–21) 6 (3–11) 0.05 Survivors 34 (64.2%) 24 (48.0%) 0.07 APACHE II, mean 23.2 25.4 0.17 Medical 31 (62%) 35 (70%) 0.53 Surgical 19 (38%) 15 (30%) 0.53 Table 1 (abstract P130) Median capillary blood glucose (CBG) at different time points. S52 Available online http://ccforum.com/supplements/11/S2 9.9 mmol/l, Group R 9.4 mmol/l and 8.3 mmol/l, P = 0.04 and 0.02, respectively) (Figure 1). There were three episodes of hypoglycemia in Group G and one in Group R, which were corrected. 9.9 mmol/l, Group R 9.4 mmol/l and 8.3 mmol/l, P = 0.04 and 0.02, respectively) (Figure 1). There were three episodes of hypoglycemia in Group G and one in Group R, which were corrected. Diurnal and other variations in blood glucose in intensive care unit patients receiving insulin infusions S Smith, K Oveson, W Strauss, A Ahmann, D Hagg OHSU, Portland, OR, USA Critical Care 2007, 11(Suppl 2):P133 (doi: 10.1186/cc5293) Conclusion OD s.c. glargine insulin is a safe and effective alternative to regular insulin for glycemic control in critically ill patients. P132 Introduction Treatment of hyperglycemia in ICU patients using an insulin infusion protocol was shown by van den Berghe and colleagues to reduce mortality and morbidity in ICU patients. Consequently, many healthcare bodies proposed guidelines for the control of hyperglycemia in the ICU. However, the patchy evidence underpinning these guidelines and a high rate of complications lead to controversy about the optimal glucose target range. Studies showing insulin infusions are effective have reported average glucose values at single time points. However, single time points are difficult to interpret as they do not provide information about the proportion of glucose measurements that need to be in range for benefit. We hypothesized that blood glucose variance was greater if all glucose measurements were considered and asked whether there was a diurnal pattern that accounted for some of the variance. Investigation of insulin clearance in severely acutely ill patients with glucose intolerance evaluated by means of bedside-type artificial pancreas The method of investigation involved patients being classified into four groups according to IC, and those groups were compared with each other; low IC group (group L: IC < 9, n = 2), normal IC group (group N: 9 < IC < 15, n = 13), high IC group (group H: 15 < IC, n = 8), and severely high IC group (group S: 19 < IC, n = 5) (group S was a subgroup of group H). Results We compared the 6:00 a.m. glucose value with those collected at all other times in 149 consecutive patients. The 6:00 a.m. values were lower than the remaining values (mean ± SD: 112 ± 30 mg/dl (n = 477) vs 119 ± 35 mg/dl (n = 10,364); P < 0.0001) and as hypothesized had a smaller variance by F test (P < 0.0001). Inspection of the time-averaged data (±SE) revealed a diurnal variation in the blood glucose with peaks occurring at 11:00 a.m. and 10:00 p.m. (Figure 1). This diurnal pattern may account for some of the observed variation in insulin requirements and contribute to episodes of hypoglycemia in the critically ill. Conclusion Glucose variance is increased if all time values are considered rather than a single time point and there is a diurnal pattern to glucose in ICU patients receiving insulin. Consideration of this diurnal variation when treating hyperglycemia in the ICU may avoid hypoglycemia and so facilitate better glucose control with insulin infusions. Results (1) FFA values were low or normal in all groups. (2) There were no significant differences in stress hormones among group N, group H, and group S. Those hormones in group L were significantly higher than, or had a tendency to be higher than, those in group N, group H, and group S. (3) The mean values of BGm in the groups had a tendency to be higher in the order of group S (179 ± 30), group H (172 ± 25), group N (162 ± 26), and group L (153 ± 8). (4) The severities of the diseases (sepsis (%)/SOFA score/mortality (%)) in the groups were significantly higher in the order group L (100%/20.0 ± 1.4/100%), group S (100%/ 9.6 ± 7.0/40%), group H (88%/7.0 ± 6.5/25%), and group N (54%/5.8 ± 5.2/15%). Severe hypoglycaemia during intensive insulin therapy: a rare event in critically ill patients Severe hypoglycaemia during intensive insulin therapy: a rare event in critically ill patients M Kaukonen, M Rantala, V Pettilä, M Hynninen Helsinki University Hospital, Helsinki, Finland Critical Care 2007, 11(Suppl 2):P134 (doi: 10.1186/cc5294) Introduction Tight glycemic control reduces mortality in surgical intensive care patients and in long-term medical intensive care patients. The incidence of severe hypoglycaemia (glucose ≤2.2 mmol/l) in the intensive treatment group has been 3.1–5.1%. Recently, a large study on intensive insulin therapy was prematurely discontinued due to safety issues. The incidence of hypoglycaemia was 9.8% in intensive treatment group and the mortality among patients experiencing hypoglycaemia was 18.6%. As the safety of intensive insulin therapy has been questioned, we screened all patients during a 17-month period to see the incidence of hypoglycaemia and its effects on the prognosis of the patients. Results Forty patients, 22 (55%) males and 18 (45%) females, who received nutritional support for 48 hours or more were studied. The mean (SD) age was 59.4 (14.7) years. Enteral feeding was given in 32 (80%) and parenteral feeding in 14 (35%) patients, while six (15%) patients received both enteral and parenteral feeding. The mean (SD) energy in 48 hours was 3,307.4 (527.0) kcal, mean (SD) insulin was 1.37 (1.23) IU, mean (SD) blood glucose was 7.76 (0.9) mmol/dl and total insulin to achieve glycaemic control was 65.51 (58.6) IU. The time taken (SD) to achieve glycaemic control was 15.16 (12.65) hours. As expected, there was a relationship between the total insulin dose and the time to achieve three consecutive glycaemic controls (r = –0.43, P = 0.023). Also, between the total insulin dose and mean blood glucose r = 0.508, P = 0.001. There was no significant relation- ship between the total insulin dose and indication for ICU admission, and the total insulin dose and body mass index. Methods A retrospective study was performed in two ICUs, one eight-bed general ICU and one 10-bed surgical ICU. All patients treated between 7 February 2005 and 30 June 2006 were included in the study. A nurse-driven intensive insulin protocol with a target blood glucose level of 4–6.1 mmol/l had been introduced in 2004. All blood glucose measurements performed during the ICU treatment were analysed. The patients were divided into two groups according to the lowest detected blood glucose value (≤2.2 or ≥2.3 mmol/l). P136 Implementation of glycemic control – problems and solutions Implementation of glycemic control – problems and solutions E Halbeck, U Jaschinski, A Scherer, A Aulmann, M Lichtwarck-Aschoff, H Forst Klinikum Augsburg, Germany Critical Care 2007, 11(Suppl 2):P136 (doi: 10.1186/cc5296) Introduction Glycaemic control is another example of protocol- driven therapy in intensive care medicine to improve outcome in critically ill patients. While the advantage of this approach seems to be obvious, little is known about the problems of implementing such a protocol. The intention of this study was to evaluate problems of implementation and to develop strategies to overcome them. Conclusions Severe hypoglycaemia during intensive insulin therapy is rare in protocol-driven ICU treatment compared with previous clinical trials. When present, hypoglycaemia may have an impact on the outcome of the patients Setting A 16-bed surgical ICU of a university teaching hospital with 50 critical care nurses, about 30% in part-time employment. Severe hypoglycaemia during intensive insulin therapy: a rare event in critically ill patients Conclusion Findings from this study showed that the indication for admission did not affect either the total dose of insulin required to achieve glycaemic control or the time it takes to achieve three consecutive glycaemic controls. Results A total of 1,024 patients (1,124 treatment periods) were included in the study. Thirty patients were excluded due to incompleteness of the data. During the study period 61,203 blood glucose measurements were performed, 1,578 (2.6%) of which were below the target value of 4 mmol/l. Severe hypoglycaemia (≤2.2 mmol/l) occurred in 25 patients (36 measurements). The incidence was 0.059% of the measurements and 2.3% of the patients. The median age, sex, APACHE II score, SAPS II or diagnosis category did not differ between the groups. The median (IQR) ICU and hospital length of stay was 4.3 (1.8–10.6) and 18 (8.5–39.5) days in patients with lowest blood glucose ≤2.2, and 2.7 (1.2–5.7) and 13 (7–23) days in patients with lowest blood glucose ≥2.3 (P = 0.058 and P = 0.077, respectively). The hospital mortalities were 25% and 15%, respectively; the difference was not statistically significant. P134 efficacy of an intensive insulin therapy protocol in achieving glycaemic control in patients presenting with different conditions. Methods A prospective observational study was performed over 8 weeks on patients admitted to an adult ICU who received nutrition support for up to 48 hours. Intensive insulin therapy was administered to those patients who developed hyperglycemia. The demographics, blood glucose and insulin doses were documented. Haemoglobin, white cell count, neutrophil count, antioxidants, CRP and prealbumin were measured. Outcome measures were the mean and total insulin dose and the time to achieve glycaemic control. P134 Severe hypoglycaemia during intensive insulin therapy: a rare event in critically ill patients M Kaukonen, M Rantala, V Pettilä, M Hynninen Helsinki University Hospital, Helsinki, Finland Critical Care 2007, 11(Suppl 2):P134 (doi: 10.1186/cc5294) Figure 1 (abstract P133) Figure 1 (abstract P133) Interpretation and conclusions The increase of IC was related to glucose intolerance. IC increased and glucose intolerance became severe as the severity of the diseases progressed. In the most severe state, or in a near-terminal state, however, IC decreased and glucose intolerance improved, although stress hormones increased significantly. Therapies focused on the improvement of IC were considered important in acutely ill severe patients with glucose intolerance as well as blood glucose control by insulin therapy. S53 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin P137 Computer-advised insulin infusion in critically ill patients – a randomized controlled trial J Cordingley1, N Dormand1, S Squire1, M Wilinska2, L Chassin2, R Hovorka2, C Morgan1 1Royal Brompton Hospital, London, UK; 2University of Cambridge, UK Critical Care 2007, 11(Suppl 2):P137 (doi: 10.1186/cc5297) Computer-advised insulin infusion in critically ill patients – a randomized controlled trial Methods This was an open randomized controlled clinical study. Fifty mechanically ventilated medical ICU patients were included for a study period of 72 hours. Patients were randomized either to a control group, treated by an insulin algorithm as routinely used in the ICU, or to the MPC group, using a laptop-based fully automated MPC algorithm. The target range for blood glucose (BG) was 4.4–6.1 mM for both groups. Efficacy was assessed by calculating the median BG, hyperglycaemic index (HGI) and BG sampling interval. Safety was assessed by the number of hypoglycaemic BG measurements < 2.2 mM. Introduction Tight blood glucose (BG) control has been shown to decrease morbidity and mortality in patients in the surgical ICU [1] but is difficult to achieve using standard insulin infusion protocols. We previously evaluated a software model predictive control (MPC) insulin administration algorithm in postcardiac surgery patients [2]. This study investigated the use of an enhanced MPC algorithm (eMPC) in more severely ill patients over 72 hours. Results Patients were included for 72 (69–73) hours (median (IQR)) in the control group and 71 (70–73) hours in the MPC group. The median BG and HGI were significantly lower in MPC vs control patients (see Table 1). A single BG measurement < 2.2 mM was detected in the MPC group vs 0 in the control group. The sampling frequency was significantly higher in the MPC group. Methods Fourteen (seven male) critically ill ventilated medical and surgical patients, mean age 65 years, with an arterial BG > 6.7 mmol/l within 24 hours of ICU admission (RBH) or already receiving insulin infusion, and expected to require mechanical ventilation for more than 72 hours, were treated either with BG control by the standard ICU insulin intravenous infusion protocol [2] or eMPC-advised insulin infusion (n = 6) for 72 hours. The eMPC algorithm, installed on a bedside computer, requires input of current insulin requirements, bodyweight, carbohydrate intake and BG concentration. The algorithm advises the time to next BG sample (up to 4 hours) and the insulin infusion rate, targeted to maintain BG at 4.4–6.1 mmol/l. P135 , p p y Method Over a 7-month period all patients staying longer than 48 hours in the ICU with hyperglycaemia (>150 mg%) on three consecutive measurements were included in the study. These patients were treated according to a protocol at the discretion of the attending nurse. On daily rounds and every 4–5 weeks supervision was performed, and the protocol was modified three times during this period according to staff comments. Further on, medical as well as nonmedical problems of implementation were analysed and discussed. Attitudes and perceived impeding aspects of the implementation process were recorded by means of a questionnaire. Intensive insulin therapy and indications for intensive care admission A Sanusi1, I Welters2, A Shenkin2, P Turner3, B Perry2 1University of Ibadan, Ibadan, Nigeria; 2University of Liverpool, UK; 3The Royal Liverpool Hospital, Liverpool, UK Critical Care 2007, 11(Suppl 2):P135 (doi: 10.1186/cc5295) Introduction Insulin resistance and hyperglycemia are common in critically ill patients, and are associated with higher morbidity and mortality in these patients if not controlled. Intensive insulin therapy has been shown to reduce morbidity and mortality. It is not clear, however, whether the patients’ indication for admission into the ICU is related to the time to achieve glycaemic control or the total dose of insulin required. This study was designed to audit the Results Since insulin sensitivity showed enormous variability, glycaemic control required a high nursing effort. Impeding aspects to titrate blood glucose into the target range were the absence of a nutritional protocol (high carbohydrate intake, despite inflam- mation/infection leading to hyperglycaemia that was difficult to S54 Available online http://ccforum.com/supplements/11/S2 Table 1 (abstract P138) Table 1 (abstract P138) MPC group (n = 25) Control group (n = 25) P BG (mM) 5.9 (5.5–6.3) 7.4 (6.9–8.6) <0.001 HGI (mM) 0.37 (0.17–0.91) 1.56 (1.06–2.45) <0.001 Interval (min) 105 (94–139) 173 (160–194) <0.001 Data presented as the median (IQR). Data presented as the median (IQR). Results The mean (SD) glucose concentration was significantly lower in the eMPC group (6.0 (0.34) vs 7.1 (0.54) mmol/l, P < 0.001). The mean insulin infusion rate was not significantly different (4.1 (2.7) vs 3.1 (1.8) IU/hour, eMPC vs standard care). BG sampling occurred more frequently in the eMPC group, with a mean of every 1.1 vs 1.9 hours (P < 0.05). No patients in either group had any BG measurements <2.2 mmol/l. Conclusion The use of MPC improved BG and the HGI. This improvement was accompanied by an increased sampling frequency. MPC with time-variant sampling is a reliable tool for the implementation of TGC in patients in the medical ICU. P138 control) and fear of hypoglycaemia (<60 mg%) leading to low-dose insulin with consecutive hyperglycaemia. Lack of communication (and therefore a loss of information) between critical care nurses and the intensivists and poor acceptance from physicians to leave this field of intensive care medicine to the nurses were additional factors that slowed the implementation process. P138 Evaluation of a model predictive control algorithm using time-variant sampling to establish tight glycaemic control in clinical practice C Pachler1, J Plank1, H Weinhandl1, R Hovorka2, L Chassin2, P Kaufmann1, KH Smolle1, TR Pieber1, M Ellmerer1 1Medical University Graz, Austria; 2Addenbrooke’s Hospital, Cambridge, UK Critical Care 2007, 11(Suppl 2):P138 (doi: 10.1186/cc5298) Evaluation of a model predictive control algorithm using time-variant sampling to establish tight glycaemic control in clinical practice C Pachler1, J Plank1, H Weinhandl1, R Hovorka2, L Chassin2, P Kaufmann1, KH Smolle1, TR Pieber1, M Ellmerer1 1Medical University Graz, Austria; 2Addenbrooke’s Hospital, Cambridge, UK Critical Care 2007, 11(Suppl 2):P138 (doi: 10.1186/cc5298) Evaluation of a model predictive control algorithm using time-variant sampling to establish tight glycaemic control in clinical practice C Pachler1, J Plank1, H Weinhandl1, R Hovorka2, L Chassin2, P Kaufmann1, KH Smolle1, TR Pieber1, M Ellmerer1 1Medical University Graz, Austria; 2Addenbrooke’s Hospital, Cambridge, UK Critical Care 2007, 11(Suppl 2):P138 (doi: 10.1186/cc5298) Conclusion Implementation of protocol-driven medicine requires a high quality of information flow. The lack of linearity between blood glucose and insulin dose (variability of insulin sensitivity) required a sometimes intuitive (experienced) decision to titrate the insulin dose. The conflict of physicians with this new role of critical care nurses might be due to the lack of understanding of the evolution of the nursing profession. Introduction Tight glycaemic control (TGC) in critically ill patients significantly improves clinical outcome. Even with increased workload for ICU nursing staff, targets for TGC are often not achieved. The aim of the present study was to evaluate in clinical practice a model predictive control algorithm (MPC) using time- variant sampling, which will be used in a fully automated insulin titration system (CLINICIP system). P139 Conclusion The eMPC algorithm was effective in maintaining tight BG control in this more severely ill patient group without any episodes of hypoglycaemia (BG < 2.2 mmol/l), but required more frequent BG measurement. The effect of tighter glucose control on outcome P137 Patients in the eMPC group had BG measured hourly (for safety) but values were only entered if requested by the algorithm. The effect of tighter glucose control on outcome I Meynaar, P Tangkau, S Sleeswijk Visser, M van Spreuwel-Verheijen, L Dawson Reinier de Graaf Gasthuis, Delft, The Netherlands Critical Care 2007, 11(Suppl 2):P139 (doi: 10.1186/cc5299) Acknowledgements This study is part of the CLINICIP project funded by the EC (6th Framework). The University of Cambridge also received support from EPSRC (GR/S14344/01). Critical Care 2007, 11(Suppl 2):P139 (doi: 10.1186/ Introduction Evidence is accumulating that tight glucose control improves outcome in critically ill patients. This study was performed to evaluate the effect of lower blood glucose levels in critically ill patients on outcome. References 1. Van den Berghe G, et al.: Intensive insulin therapy in criti- cally ill patients. N Engl J Med 2001, 345:1359-1367. 1. Van den Berghe G, et al.: Intensive insulin therapy in criti- cally ill patients. N Engl J Med 2001, 345:1359-1367. 2. Plank J, et al.: Multicentric randomized controlled trial to evaluate blood glucose control by the MPC versus routine glucose management protocols in ICU patients. Diabetes Care 2006, 29:271-276. Patients and methods The unit is a 10-bed closed-format medical–surgical ICU in a general hospital. Starting in 2003 insulin was prescribed to ICU patients using several nurse-driven S55 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Figure 1 (abstract P140) Figure 1 (abstract P140) computerised protocols, each subsequent protocol aiming for lower glucose levels. From February 2004 until May 2005 protocol 1 was used, aiming for glucose between 5.0 and 9.0 mmol/l; from July 2005 until December 2005 protocol 2 was used, aiming for glucose between 4.5 and 7.5 mmol/l. Serum glucose was measured at 6:00 a.m. in all patients from blood derived from arterial lines or venous puncture. The rest of the day blood glucose was measured either using the Glucotouch (protocol 1) or the AccuCheck (protocol 2) devices. To eliminate differences due to these different methods of measurement, only the 6:00 a.m. glucose measurements done by the central laboratory were studied here. Data were derived from ICU and laboratory databases. arterial blood measurements: Accu-chek Advantage® (Roche) arterial, venous and capillary samples; and Precision PCx® (Abbott) arterial samples. All samples were collected simul- taneously. Agreement between measurements was tested with the Bland–Altman method. Results See Table 1. The median morning glucose was reduced from 7.5 mmol/l with protocol 1 to 6.8 mmol/l with protocol 2, resulting in small but nonsignificant improvement in outcome. Subgroup analysis focusing on medical or surgical patients or on patients with specific length of stay in the ICU also revealed nonsignificant differences in outcome. Results Comparisons between pairs of measurements are shown in Figure 1. Conclusions The two glucose meters evaluated might not be sufficiently reliable to be used in the ICU setting, especially for patients under strict blood glucose control. P141 Implementing tight glycaemic control: performance of bedside glucometers D Vlasselaers1, K Vandewiele2, T Van Herpe2, B De Moor2, G Van den Berghe1 1University Hospital Gasthuisberg, Leuven, Belgium; 2Katholieke Universiteit Leuven, Belgium Critical Care 2007, 11(Suppl 2):P141 (doi: 10.1186/cc5301) Introduction Implementing tight glycaemic control (TGC) in the ICU requires accurate blood glucose (BG) monitoring. We evaluated the performance of two bedside glucometers (GM) in ICU patients. Methods Four hundred and fifty-two arterial blood samples were prospectively analysed in 37 adult ICU patients subjected to TGC. Arterial BG was simultaneously determined using a reference test (ABL®) and two GM (Accu-Chek® and HemoCue®). Data were Conclusions A small but significant decrease in serum glucose probably results in a small but statistically nonsignificant decrease in mortality and length of stay. References Moreover, there are marked differences between the equipment and a decrease in precision if capillary or venous samples are used. Table 1 (abstract P139) Protocol 1 Protocol 2 P Number of patients 601 413 Number of morning 1,558 1,378 glucose measurements Morning glucose 8.23/7.5 7.48/6.8 <0.001 (mean/median) APACHE II score at ICU 13.6/12 13.9/12 Not significant admission (mean/median) Age (years, mean/median) 66.4/70.3 67.1/70.6 Not significant ICU mortality all patients (%) 10.6 9.0 Not significant Hospital mortality all 17.6 15.0 Not significant patients (%) Mean ICU length of stay 3.04/1.1 2.47/1.1 Not significant (days, mean/median) Mean hospital length of 17.00/10.0 13.62/9.1 Not significant stay (days, mean/median) P143 Results Correlation between the reference method and both GM in the overall BG range was reasonable, but not perfect (r2 ≥0.93). This was further underlined by BA analysis (Figures 1 and 2), showing a bias to overestimate BG with GM. In the TGC range (80–110 mg/dl) correlation was low for both GM (r2 ≤0.66). This was confirmed by BA analysis, demonstrating broad limits of agreement: +14.2 and –26.6 mg/dl for Accu-Chek® and +5.5 and –31.1 mg/dl for HemoCue®. Results Correlation between the reference method and both GM in the overall BG range was reasonable, but not perfect (r2 ≥0.93). This was further underlined by BA analysis (Figures 1 and 2), showing a bias to overestimate BG with GM. In the TGC range (80–110 mg/dl) correlation was low for both GM (r2 ≤0.66). This was confirmed by BA analysis, demonstrating broad limits of agreement: +14.2 and –26.6 mg/dl for Accu-Chek® and +5.5 and –31.1 mg/dl for HemoCue®. Conclusions The accuracy of the tested GM in our ICU patients was insufficient for safe clinical practice. Therefore, to avoid potentially harmful hypoglycaemia, caution is warranted when TGC is implemented exclusively based on BG results obtained by GM. Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Figure 2 (abstract P141) arterial) and on the Rapid-Lab 1265 Bayer (GO, arterial), and each value was compared with the reference laboratory result. Results A total of 262 matched analyses were done in 60 patients. Biases are defined as the glucose laboratory value minus point-of- care value. The bias, 95% limits of agreement, and numbers of observed discrepancy (d) paired results >20% and >10% are reported in Table 1. arterial) and on the Rapid-Lab 1265 Bayer (GO, arterial), and each value was compared with the reference laboratory result. p y Results A total of 262 matched analyses were done in 60 patients. Biases are defined as the glucose laboratory value minus point-of- care value. The bias, 95% limits of agreement, and numbers of observed discrepancy (d) paired results >20% and >10% are reported in Table 1. Conclusions GO methods underestimate while GD methods overestimate all blood glucose levels as compared with plasma glucose levels measured by the reference method of hexokinase. Capillary methods have wider 95% limits of agreement than measures carried out on arterial blood. P143 Continuous glucose monitoring for intensive care patients using whole blood microdialysis F Feichtner1, R Schaller1, A Fercher1, L Schaupp1, J Plank2, A Wutte2, M Ellmerer2, T Pieber2 1Joanneum Research GmbH, Graz, Austria; 2Medical University Graz, Austria Critical Care 2007, 11(Suppl 2):P143 (doi: 10.1186/cc5303) Continuous glucose monitoring for intensive care patients using whole blood microdialysis analysed using linear regression and the Bland–Altman (BA) method. Introduction The objective of this study was to investigate whether continuous glucose monitoring for intensive care patients could be implemented using blood microdialysis (MD) as tight glycaemic control reduces mortality and morbidity of critically ill patients. Currently investigated is whether the subcutaneous tissue is an adequate and representative site for glucose monitoring. We have designed and tested a novel system that allows continuous measurement of glucose concentration in whole blood based on MD. Methods Na-heparin is pumped to the tip of a double lumen catheter and the blood–heparin mixture is withdrawn continuously at a mixing ratio of 1:1 at a flow of 4 ml/hour. The blood–heparin mixture is microdialysed in a planar flow-through MD unit and is discarded thereafter. The dialysate is collected and analysed for glucose concentration via Beckman analysis and referred to venous blood samples taken from the reference arm. Eight healthy volunteers underwent a 12-hour investigation including an OGTT. Glucose readings from dialysate and venous blood were obtained in a 15–30 minute interval. Introduction The objective of this study was to investigate whether continuous glucose monitoring for intensive care patients could be implemented using blood microdialysis (MD) as tight glycaemic control reduces mortality and morbidity of critically ill patients. Currently investigated is whether the subcutaneous tissue is an adequate and representative site for glucose monitoring. We have designed and tested a novel system that allows continuous measurement of glucose concentration in whole blood based on MD. Methods Na-heparin is pumped to the tip of a double lumen catheter and the blood–heparin mixture is withdrawn continuously at a mixing ratio of 1:1 at a flow of 4 ml/hour. The blood–heparin mixture is microdialysed in a planar flow-through MD unit and is discarded thereafter. The dialysate is collected and analysed for glucose concentration via Beckman analysis and referred to venous blood samples taken from the reference arm. Eight healthy volunteers underwent a 12-hour investigation including an OGTT. Glucose readings from dialysate and venous blood were obtained in a 15–30 minute interval. Figure 1 (abstract P141) Reliability of arterial, capillary and venous point-of-care glucose measurements in the intensive care unit setting: evaluation of two glucometers A Pereira, A Cavalcanti, T Correa, F Almeida, E Figueiredo, E Silva Hospital Israelita Albert Einstein, São Paulo, Brazil Critical Care 2007, 11(Suppl 2):P140 (doi: 10.1186/cc5300) A Pereira, A Cavalcanti, T Correa, F Almeida, E Figueiredo, E Silva Hospital Israelita Albert Einstein, São Paulo, Brazil Critical Care 2007, 11(Suppl 2):P140 (doi: 10.1186/cc5300) Introduction Increased risk of hypoglycemia is the major drawback of strict glycemic control, which has been extensively used in critically ill patients. Fast and precise glucose measurements are therefore mandatory. Our aim was to evaluate the accuracy of two methods of bedside point-of-care testing for glucose measure- ments using arterial, capillary and venous blood samples in ICU patients. Methods A cross-sectional study with prospective data collection included 86 patients admitted to a 40-bed clinical-surgical ICU of a tertiary care hospital. Results from two different methods of glucose measurement were compared with central laboratory S56 Available online http://ccforum.com/supplements/11/S2 P144 Subcutaneous glucose monitoring in patients with severe sepsis Subcutaneous glucose monitoring in patients with severe sepsis JK Mader1, S Korsatko1, D Ikeoka1, J Plank1, M Bodenlenz2, M Suppan2, F Sinner2, KH Smolle1, TR Pieber1, M Ellmerer1 1Medical University Graz, Austria; 2Joanneum Research GmbH, Graz, Austria Critical Care 2007, 11(Suppl 2):P144 (doi: 10.1186/cc5304) Results During 2 months 55 patients (male 47%, female 53%) were admitted, including 47 (85%) emergency admissions. Thirty- three (60%) patients stayed in the unit for >48 hours with an average stay of 7.1 days. Thirty-two (58%) patients received NS, and 26 (81%) of these were within 48 hours of admission. Enteral and parenteral routes were used in 26 (81%) and six (18%) patients, respectively. In five (15%) patients both methods were used during the change of route of administration. The daily calorie intake expressed as a percentage of the recommended intake is presented in Table 1. HE was more than 300 in 70% of the 570 measurements. Blood sugar was between 6.3 and 6.9 mmol/l. Gastro Prokinetics was used in 80%. There was no feeding protocol in the unit and low GRVTs were used before abandonment of the enteral regime. Introduction Tight glycemic control (TGC) to improve mortality and morbidity in ICU patients requires frequent blood glucose measurements and thus increases the workload for medical staff. TGC could be simplified by subcutaneous glucose monitoring as suggested for diabetes care. Due to altered tissue perfusion as often seen in critically ill patients, it remains unclear whether subcutaneous adipose tissue (SAT) is a reliable measurement site. In this study we evaluated clinically whether SAT can be used as safe, alternative site to establish TGC in patients with severe sepsis. Methods For 26 hours, arterial blood and SAT microdialysis samples were taken from 10 patients with severe sepsis. Hourly SAT glucose concentrations were calibrated to arterial blood glucose (Bg) by one-point calibration either 1 hour (BgSAT1h) or 6 hours (BgSAT6h) after catheter insertion. The relation between Bg and calibrated SAT glucose readings was clinically evaluated applying a well-established insulin titration error grid analysis. ( Table 1 (abstract P145) Total days (%) Calories (%) Nitrogen (%) Nasogastric feeds 155 (71.5) 80.21 63.5 Total parenteral nutrition 48 (22.22) 151.52 118.1 Nasogastric feeds + 13 (6.06) 158.01 126.9 total parenteral nutrition Results Arterial and SAT glucose readings were comparable (Bg: 143 (122–167) mg/dl; BgSAT1h: 147 (130–177) mg/dl; BgSAT6h: 146 (117–181) mg/dl; median (IQR)). P144 Relative differences between Bg vs BgSAT1h and BgSAT6h indicated –2 (–193 to 30)% and –4 (–42 to 25)%; median (5th and 95th percentiles)), respectively. Clinical evaluation of the data indicated that 86% (BgSAT1h) and 95% (BgSAT6h) of the glucose readings from SAT would allow correct treatment according to an insulin-titration guideline. Fourteen percent of the data for BgSAT1h and 5% of the data for BgSAT6h would cause a violation of the guideline and thus unwanted glucose excursions and a possible risk for the patient. Conclusion We found that there was overfeeding in the parenteral and combined routes. HE was satisfactory in 70% and more patients could receive enteral feeds if a high GRVT was used. Small-bore tubes are easy to implement and were not practised. Reference 1. Dhaliwal R, Heyland DK: Nutrition and infection in the inten- sive care unit: what does the evidence show? Curr Opin Crit Care 2005, 11:461-467. P146 g p p Conclusions Clinical evaluation of subcutaneous glucose monitoring to establish TGC indicated that only 86% of the readings would allow acceptable treatment according to a titration guideline. Although this result could be substantially improved by introducing a 6-hour stabilisation period for the trauma caused by catheter insertion, the clinical applicability of subcutaneous glucose monitoring for patients with sepsis has to be considered with care. Prokinetics effect on gastric emptying in critically ill ventilated patients measured by the C13 breath test with a novel device M Hersch, V Krasilnikov, S Einav, D Braverman, S Zevin, P Risseman Shaare Zedek Med. Centre, Jerusalem, Israel Critical Care 2007, 11(Suppl 2):P146 (doi: 10.1186/cc5306) M Hersch, V Krasilnikov, S Einav, D Braverman, S Zevin, P Risseman Shaare Zedek Med. Centre, Jerusalem, Israel Critical Care 2007, 11(Suppl 2):P146 (doi: 10.1186/cc5306) M Hersch, V Krasilnikov, S Einav, D Braverman, S Zevin, P Risseman Shaare Zedek Med. Centre, Jerusalem, Israel Critical Care 2007, 11(Suppl 2):P146 (doi: 10.1186/cc5306) Acknowledgement Funded by the European Commission as part of CLINICIP FP6 IST 506965. Introduction Gastroparesis in critically ill ventilated patients is relieved by prokinetics. The best prokinetic combination is not known and may be identified by BreathID measurement of gastric emptying (GE). Introduction Gastroparesis in critically ill ventilated patients is relieved by prokinetics. The best prokinetic combination is not known and may be identified by BreathID measurement of gastric emptying (GE). Comparison of accuracy of glucose-oxidase-based and glucose-dehydrogenase-based point-of-care glucometers Thirty-two (58%) patients received NS, and 26 (81%) of these were within 48 hours of admission. Enteral and parenteral routes were used in 26 (81%) and six (18%) patients, respectively. In five (15%) patients both methods were used during the change of route of administration. The daily calorie intake expressed as a percentage of the recommended intake is presented in Table 1. HE was more than 300 in 70% of the 570 measurements. Blood sugar was between 6.3 and 6.9 mmol/l. Gastro Prokinetics was used in 80%. There was no feeding protocol in the unit and low GRVTs were used before adequate flushing sequences or by using it with central lines. Further long-term studies are necessary to test the system together with online sensors. assess the compliance of nutritional practise in our ICU with some aspects of recommendations of Canadian Clinical Guidelines. assess the compliance of nutritional practise in our ICU with some aspects of recommendations of Canadian Clinical Guidelines. Method Demographic data, head elevation (HE) from the horizontal position, daily nitrogen and calorie intake were recorded. Daily recommended calorie requirements were calculated according to body weights on admission. The nasogastric tube size and the gastric residual volume threshold (GRVT) before abandoning enteral feeds were also recorded. Method Demographic data, head elevation (HE) from the horizontal position, daily nitrogen and calorie intake were recorded. Daily recommended calorie requirements were calculated according to body weights on admission. The nasogastric tube size and the gastric residual volume threshold (GRVT) before abandoning enteral feeds were also recorded. Comparison of accuracy of glucose-oxidase-based and glucose-dehydrogenase-based point-of-care glucometers A Roman, A Janier-Dubry, C Hanicq, P Flament, F Vertongen, E Stevens CHU Saint-Pierre, Brussels, Belgium Critical Care 2007, 11(Suppl 2):P142 (doi: 10.1186/cc5302) Results All eight subjects successfully completed the 12-hour trial. The coefficient of correlation between continuously withdrawn microdialysed blood and venously taken reference blood samples was r = 0.9834 (0.9753–0.9958). The Clark Error Grid Analysis (EGA) revealed that 99.5% of all data pairs are in the A range (220 of 221). Applying the novel Insulin Titration EGA yielded in 100% of data pairs the ‘acceptable treatment’ area. Introduction Bedside capillary or arterial blood glucose monitoring is mandatory for ICU patients under tight glycemic control. Point- of-care methods are based on glucose-oxidase (GO) or glucose- dehydrogenase (GD) enzymatic methods whereas the laboratory reference method is hexokinase for measuring the plasma glucose levels. Conclusions Blood MD based on continuous blood withdrawal and extracorporeal MD is a promising approach to obtain dialysate reliably, safely and continuously for long-term determination of blood glucose concentration with online sensors. The correlation between glucose concentration of dialysate and reference venous blood samples is excellent. The patency of the double lumen catheter in the current form could be improved by introducing Methods In this prospective observational study, blood glucose was simultaneously measured on the Glucocard Arkray (GO, capillary), on the Accu-chek Inform Roche (GD, capillary and S57 Table 1 (abstract P142) Number of Bias Agreement Number >20% Number >10% Point-of care method comparisons (mg/dl) (mg/dl) d (%) d (%) Glucocard, GO capillary 262 +8.5 ±36 32 (12) 103 (39) Accu-chek, GD capillary 262 –6.3 ±37 40 (15) 123 (45) Rapid-Lab, GO arterial 262 +5.3 ±11 (0) 21 (8) Accu-chek, GD arterial 234 –7.9 ±17 17 (7) 67 (29) S57 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin assess the compliance of nutritional practise in our ICU with some aspects of recommendations of Canadian Clinical Guidelines. Method Demographic data, head elevation (HE) from the horizontal position, daily nitrogen and calorie intake were recorded. Daily recommended calorie requirements were calculated according to body weights on admission. The nasogastric tube size and the gastric residual volume threshold (GRVT) before abandoning enteral feeds were also recorded. Results During 2 months 55 patients (male 47%, female 53%) were admitted, including 47 (85%) emergency admissions. Thirty- three (60%) patients stayed in the unit for >48 hours with an average stay of 7.1 days. P148 Proton pump inhibitors and the incidence of Clostridium difficile on the intensive care unit I Whitehead, J Smith, R Bellamy, S Bonner James Cook University Hospital, Middlesbrough, UK Critical Care 2007, 11(Suppl 2):P148 (doi: 10.1186/cc5308) Proton pump inhibitors and the incidence of Clostridium difficile on the intensive care unit Proton pump inhibitors and the incidence of Clostridium difficile on the intensive care unit percentage dose recovered (PDR), a measure of delta over baseline reflecting the rate of substrate metabolized. The 13CO2 measurements and calculations were done by our BreathID Computerized system (BreathID Ltd, Jerusalem, Israel) with its sensor attached to the expiratory ventilator tubing. I Whitehead, J Smith, R Bellamy, S Bonner James Cook University Hospital, Middlesbrough, UK Critical Care 2007, 11(Suppl 2):P148 (doi: 10.1186/cc5308) Introduction Clostridium difficile associated disease (CDAD) is recognized as a major cause of morbidity and mortality among patients in hospital. There have been reported associations between the use of proton pump inhibitors (PPIs) and CDAD in community and hospital settings [1,2]. The aim of this study was to investigate the effect of introducing PPI prophylaxis in critically ill patients on the incidence of CDAD. Results Thirty-one patients were included. Figure 1 shows the PDR of all patients under the different prokinetic drugs. Table 1 presents the average percentage of GE improvement over BM with different therapies, and the average improvement of individuals’ best combination. Comparing 20 patients, BM first, with 11 at different timings, revealed no difference of baseline or best combination (P = 0.1, P = 0.2, respectively). p Methods Retrospective analysis of microbiology results of patients admitted to general and neurotrauma ICUs between February 2002 and September 2006. Prior to March 2004 the general ITU used PPIs for all patients as gastric acid prophylaxis, and the neurotrauma ITU used PPIs for only patients at high risk of GI ulceration. Following instigation of ventilator care bundles in March 2004 both units gave PPIs to all ventilated patients. The incidence of C. difficile toxin-positive samples and the number of doses of PPI used each month were compared for before and after this time period. The use of antibiotics was also compared between the two units over the time period to exclude this as a confounding variable. Results We identified 92 C. difficile-positive faecal samples during the 57-month period from February 2002 to September 2006. This averaged 1.61 cases per month. P148 The general ITU (ITU2) presented 49 cases (53.2%), and the neurotrauma ITU (ITU3) 43 cases (46.8%). In February 2002, PPI usage was infrequent in the ITU3, but more common in ITU2. The C. difficile rates were also higher in ITU2 than in ITU3. PPI usage increased in ITU3 until, on the instigation of the ventilator care bundle, PPIs were used for all patients from March 2004. Our preliminary data demonstrate an increase in C. difficile rates in ITU3, to meet the rates of ITU2, at the same time as PPI usage was increased (Figure 1). The ITUs back onto each other and share the same medical and nursing staff. Antibiotic usage was similar across both units with regards to cephalosporins, meropenem and pipracillin/tazobactam. Conclusion C. difficile rates have remained relatively stable on the general ITU (ITU2) but showed a significant increase on the Conclusions In this population: 1. Metoclopramide is poor in improving GE. 2. The combination of metoclopramide and continuous erythromycin is the most effective. 3. The BreathID is a convenient and novel way to monitor GE in order to study and individually tailor the most effective (up to 85% over BM) prokinetic combination. Available online http://ccforum.com/supplements/11/S2 Figure 1 (abstract P146) Results Fifty-two patients receiving ETF were observed for a total of 7,349 hours: 67.3% of patients were surgical and 32.7% medical. Patients received a median of 75% of their ideal calorific requirement. Feeding was started a median of 15 hours after admission, and a median of 5% of feeding time was interrupted after ETF had been started. Reasons for interruption included high gastric aspirates, starvation for procedures and displacement/ blockage of feeding tube. The time to start ETF was significantly different according to admission categories (P = 0.033), with abdominal and cardiothoracic surgical patients having the greatest delays. Abdominal surgical patients also had a higher proportion of feeding interruptions due to high gastric aspirates and starvation for procedures. The SOFA score on day 1 significantly correlated with the time taken to start feeding (P = 0.008), length of total feeding interruption (P = 0.012), length of feeding interruption due to high gastric aspirates (P = 0.043), and length of feeding interruption due to starvation for procedures (P = 0.026). Table 1 (abstract P146) Metoclopramide 13.7% Metoclopramide + erythromycin continuous 50.5% Erythromycin continuous 33.3% Erythromycin x 2 38.7% Best individual 85.2% Table 1 (abstract P146) Metoclopramide 13.7% Metoclopramide + erythromycin continuous 50.5% Erythromycin continuous 33.3% Erythromycin x 2 38.7% Best individual 85.2% Table 1 (abstract P146) Metoclopramide 13.7% Metoclopramide + erythromycin continuous 50.5% Erythromycin continuous 33.3% Erythromycin x 2 38.7% Best individual 85.2% Conclusion The majority of patients received a high proportion of their ideal calorific requirement and began feeding within 24 hours. The data indicate that patients having had abdominal surgery or the sickest patients may be may be more likely to experience delays in initiation and interruptions to feeding. Nutritional support in critically ill patients S Thanthulage1, Y Yoganathan2, S Tharmalingam1, M Kumara1 1Oldchurch Hospital, Romford, UK; 2BHR NHS Trust, Brentwood, UK Critical Care 2007, 11(Suppl 2):P145 (doi: 10.1186/cc5305) Methods A prospective crossover study in stable ventilated ICU patients without upper gastrointestinal pathology. GE measure- ment: 4-hours expiratory 13CO2 recording following intragastric administration of C13 sodium acetate in 100 ml Osmolite. Baseline measurement (BM) and following 24 hours i.v. therapy with: metoclopramide (10 mg every 6 hours), metoclopramide with continuous erythromycin (10 mg/hour), continuous erythromycin and bolus erythromycin (200 mg every 12 hours) were done in each patient. The BM and drug administration order was altered in a subgroup of patients. GE was assessed by calculating the Introduction Early adequate nutritional support (NS) in critically ill patients can improve clinical outcome [1]. Although enteral nutrition is considered the best method, it carries a risk for developing ventilator-associated pneumonia, particularly if patients are nursed horizontally [1]. The aim of this prospective audit is to S58 P149 Methods CRF analysis was performed on full-thickness bowel specimens obtained from shocked trauma patients requiring emergency abdominal surgery for penetrating injury, and from patients undergoing small bowel resection during elective bowel surgery. Venous blood was taken before anaesthesia, intra- operatively and on postoperative day 1. CRF extracted from tissue and blood was quantified using radioimmunoassay. On day 1 postoperatively, intestinal permeability was tested by urinary lactulose:mannitol (L:M) measurement. Institutional ethical approval was granted and patients gave written informed consent. Intestinal corticotropin-releasing factor is decreased in shocked trauma patients and may affect gut function Intestinal corticotropin-releasing factor is decreased in shocked trauma patients and may affect gut function W Michell, L Hill, S Hendricks, L Weight, S Kidson University of Cape Town, South Africa Critical Care 2007, 11(Suppl 2):P150 (doi: 10.1186/cc5310) neurotrauma ITU (ITU3), concurrent with increased PPI usage. We believe this worthy of further investigation. Introduction The reasons for the typical bowel dysfunction following traumatic injury are unclear. Corticotropin-releasing factor (CRF) in peripheral blood/tissue may induce intestinal barrier dysfunction via receptor-mediated mechanisms independently of the hypothalamic–pituitary–adrenal axis. This mechanism seems to involve interactions of CRF with enteric nerves and mast cells, which results in increased gut intercellular tight junction permeability to macromolecules, as well as increased epithelial cell apoptosis leading to loss of mucosal integrity. We investigated whether blood and intestinal tissue CRF is associated with postoperative gut dysfunction in shock. References 1. Dial S, Alrasadi K, Manoukian C: Risk of Clostridium difficile diarrhea among hospital inpatients prescribed proton pump inhibitors: cohort and case–control studies. CMAJ 2004, 171:33-38. 1. Dial S, Alrasadi K, Manoukian C: Risk of Clostridium difficile diarrhea among hospital inpatients prescribed proton pump inhibitors: cohort and case–control studies. CMAJ 2004, 171:33-38. 2. Cunnigham R: Proton pump inhibitors and the risk of Clostridium difficile associated disease: further evidence from the community. CMAJ 2006, 175:745-748. A study of enteral tube feeding in critically ill patients A Holdsworth, T Rahman St George’s Hospital, London, UK Critical Care 2007, 11(Suppl 2):P147 (doi: 10.1186/cc5307) Introduction For critically ill patients unable to eat, enteral tube feeding (ETF) is the preferred mode of feeding. The study aimed to investigate the amount of enteral feed obtained by patients on ICU in a busy London Teaching Hospital, the efficiency of initiation of feeding, and possible reasons for the failure of the above. Methods A prospective observational study was carried out over 1 month on patients admitted to a general and cardiothoracic ICU, who received ETF. Baseline data including age, reason for admission and illness severity score (SOFA) were documented. Length of time from admission to start of feeding was noted, and the volume of feed delivered to patients was recorded. The quantity of calories delivered to the patient was compared with the patient’s ideal nutritional requirement (determined by the ICU ETF protocol). Feeding interruptions were also recorded. S59 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine Figure 1 (abstract P148) Figure 1 (abstract P148) between changing tracheostomy (suggesting repeat procedures) and subsequent difficulty swallowing. One patient within this group subsequently developed a tracheal stenosis. See Table 1. Conclusion We found the percentage of patients reporting swallowing difficulties post percutaneous tracheostomy (PCT) (Portex Blue Line Ultra tracheostomy tube) to be higher than one would expect. This may be confounded by neurological injury necessitating the need for a PCT, but we feel this may be an area of concern meriting further investigation given frequent PCT in ICU practice. between changing tracheostomy (suggesting repeat procedures) and subsequent difficulty swallowing. One patient within this group subsequently developed a tracheal stenosis. See Table 1. P150 Intestinal corticotropin-releasing factor is decreased in shocked trauma patients and may affect gut function W Michell, L Hill, S Hendricks, L Weight, S Kidson University of Cape Town, South Africa Critical Care 2007, 11(Suppl 2):P150 (doi: 10.1186/cc5310) Retrospective study of dysphagia following hospital discharge of intensive care patients P Isherwood, F Baldwin Royal Sussex County Hospital, Brighton, UK Critical Care 2007, 11(Suppl 2):P149 (doi: 10.1186/cc5309) P Isherwood, F Baldwin Objective A retrospective study to assess the incidence and causal factors associated with long-term dysphagia following intensive care discharge. Results Trauma patients (n = 6, male/female = 6/0, age 27 ± 10.2 years, ISS 23 ± 6.8) were younger than elective patients (n = 6, male/female = 4/2, age 52.8 ± 7.7 years, P < 0.0006), and had significantly lower mean tissue [CRF] (0.034 ± 0.015 x 10–3% total protein (TP)) than elective patients (0.117 ± 0.075 x 10–3%TP, P = 0.023). The median (IQR) intraoperative blood CRF level was higher in trauma patients (86.7 (5.5) pg/ml vs 59.8 (9.6) pg/ml, P = 0.03) than elective patients. In trauma patients this correlated negatively with postoperative L:M (r = –0.9, P = 0.037), although intestinal permeability was greatly and equally increased in both groups (combined mean ± SD L:M, 0.58 ± 0.55). Methods A questionnaire was sent out 4 months post ICU discharge to 193 intensive care patients (Level 3 care with a stay of over 48 hours). We reviewed the case notes of those patients who reported swallowing difficulties to establish whether they had undergone, had any characteristics of or received therapies potentially associated with dysphagia. Results We had a 50% response rate to our questionnaire. An overall dysphagia post ICU stay rate of 19.5% was observed. Fever and age over 65 were both common findings as one may expect and showed the highest association with subsequent dysphagia. We did not find any suggestion of a relationship g p Conclusions CRF is detectable in bowel tissue following trauma and is significantly lower in trauma vs elective surgery patients, while CRF in blood may be a factor associated with gut barrier changes following shock and emergency laparotomy. Table 1 (abstract P149) S60 Table 1 (abstract P149) Factor Number Percentage Fever 14 82 Age > 65 years 11 58 Percutaneous tracheostomy 10 50 Sterds 7 37 Cardiopulmonary resuscitation 3 15 Shiley fenestrated low-pressure 2 10 cuffed tracheostomy tube Mini-Trach II – Seldinger 1 5 (Portex Minitracheotomy Kit) Neuromuscular Blockade 0 0 P151 Conclusions Following a severe burn, propranolol attenuates infections, inflammatory markers and fatty acid levels while improving cardiac work and endogenous anabolic hormone levels. We suggest that propranolol is a safe and efficacious modulator of th tb course and analyzed for IGF-1, IGFBP-3, and HGH. Patients underwent weekly resting energy-expenditure measurements. Statistical analysis was performed using analysis of variance with Bonferoni’s correction and Student’s t test where applicable. Results Propranolol treatment reduced heart rates by 10% and significantly improved stroke volume throughout the acute hospital stay compared with controls (P < 0.05). Resting energy expendi- ture was significantly decreased in the propranolol group when compared with controls at discharge (P < 0.05). Infection rates on admission were the same for both groups (17% propranolol vs 22% control). The incidence of infection throughout hospital course was significantly lower in the propranolol group (60%) compared with controls (87%) (P < 0.05). Propranolol significantly increased IGF-I, IGFBP-3, GH, and prealbumin, while it significantly decreased CRP and fatty acids (P < 0.05). Methods We enrolled patients admitted to our ICU who required NGT insertion for EN. A Corflow NGT with Cortrak stylet was inserted, and the position monitored using the Cortrak magnetic sensor. The Cortrak system tracks the trail of the stylet tip as it progresses towards the stomach and provides a visual represen- tation of the NGT position on a video screen, allowing rapid determination of insertion success. The position of the NGT was also assessed using pH paper and/or CXR, as appropriate, according to the standard UKNPSA guidelines. Data were analysed using a paired t test and time-to-event analysis. Conclusions Following a severe burn, propranolol attenuates infections, inflammatory markers and fatty acid levels while improving cardiac work and endogenous anabolic hormone levels. We suggest that propranolol is a safe and efficacious modulator of the postburn response. Results Fifty-two patients were recruited and 57 insertions were analysed: 32 first insertions, and 25 reinsertions. Gastric content was successfully aspirated in 40% (23/57) of insertions, and 14% (8/57) had pH 6 or above. Forty-six CXRs were requested, with three patients requiring multiple CXRs. The Cortrak correctly confirmed the position of NGT in all 57 insertions. The time required to confirm the NGT position was significantly less with the Cortrak than with conventional methods (mean ± SE Cortrak: 9.6 ± 1.7 min; pH paper: 11.6 ± 1.7 min; CXR: 122 ± 23 min; P < 0.0001). P151 There was a 1.5-hour delay in starting EN in the standard practice group compared with the Cortrak group (mean ± SE 3.98 ± 0.5 hours vs 2.58 ± 0.4 hours, P = 0.049). If the Cortrak results had been acted upon, 46 CXRs could have been avoided, which equates to a saving of £2,300 (€3,220). P153 Early enteral immunonutrition following gastric and oesophageal surgery Early enteral immunonutrition following gastric and oesophageal surgery S Vukosavljevic, T Randjelovic, D Pavlovic, J Danojlic KBC ‘Bezanijska Kosa’ Beograd, Belgrade, Serbia Critical Care 2007, 11(Suppl 2):P153 (doi: 10.1186/cc5313) Introduction The study investigates the effect of early enteral immunonutrition on patient recovery after extensive elective surgery in the upper abdomen [1,2]. It investigates the speed of patient recovery administering early enteral immunonutrition combined with total parenteral nutrition [3]. Conclusions The Cortrak demonstrated 100% accuracy in confirming the position of NGT in this patient series. It exposes patients to less radiation, facilitates earlier EN and is cost-effective. Consideration should therefore be given to including it into the standard UKNPSA guideline. Materials and methods The total of 40 patients who had undergone this type of surgery were involved in this study. Near the end of the surgery procedure a percutaneous jejunostomy was performed in 20 patients (G1), and enteral nutrition started on the first postoperative day with small doses of immunonutrient (Reconvan) 10 ml/hour. After every 12 hours the tolerance was estimated (abdominal distension, diarrhoea, vomiting). After every 24 hours the immunonutrient dose was increased by 20 ml/hour until we reached the maximum of 80 ml/hour. In the first three postoperative days the patients were also administered total parenteral nutrition, and after that only enteral nutrition. The other group of 20 patients (G2) was administered only parenteral nutrition from the first postoperative day. Preoperatively, every patient was measured for body weight, body height and body mass index, and using laboratory tests we established the levels of albumin, transferine, blood urea nitrogen and creatinine. On the third and ninth postoperative days we repeated the same laboratory tests, and measured the daily loss of nitrogen by excretion of urea in urine. Reference 1. UK National Patient Safety Agency [http://www.npsa.nhs.uk] 1. UK National Patient Safety Agency [http://www.npsa.nhs.uk] P152 Propranolol attenuates factors affecting hypermetabolism in pediatric burn patients Propranolol attenuates factors affecting hypermetabolism in pediatric burn patients W Norbury Shriner’s Hospital for Children, Galveston, TX, USA Critical Care 2007, 11(Suppl 2):P152 (doi: 10.1186/cc5312) P151 Using the Cortrak magnetic device to facilitate early enteral nutrition in critically ill patients Using the Cortrak magnetic device to facilitate early enteral nutrition in critically ill patients K Lei, J Smith, L Camporota, R Beale St Thomas’ Hospital, London, UK Critical Care 2007, 11(Suppl 2):P151 (doi: 10.1186/cc5311) K Lei, J Smith, L Camporota, R Beale St Thomas’ Hospital, London, UK Critical Care 2007, 11(Suppl 2):P151 (doi: 10.1186/cc5311) Introduction Confirmation of correct nasogastric tube (NGT) positioning is required before commencement of enteral nutrition S60 Available online http://ccforum.com/supplements/11/S2 (EN). In the ICU, however, the use of sedation, 24-hour feeding and proton pump inhibitors can make the standard confirmatory methods recommended by the UK National Patient Safety Agency (UKNPSA) [1] unreliable, and result in the need for multiple chest X-rays (CXR), increased cost and feeding delay. We studied the role of the Cortrak® (Viasys MedSystems, USA) against standard practice, and assessed the following outcomes: time required to confirm correct NGT position, time to starting feeding, and potential cost savings. (EN). In the ICU, however, the use of sedation, 24-hour feeding and proton pump inhibitors can make the standard confirmatory methods recommended by the UK National Patient Safety Agency (UKNPSA) [1] unreliable, and result in the need for multiple chest X-rays (CXR), increased cost and feeding delay. We studied the role of the Cortrak® (Viasys MedSystems, USA) against standard practice, and assessed the following outcomes: time required to confirm correct NGT position, time to starting feeding, and potential cost savings. course and analyzed for IGF-1, IGFBP-3, and HGH. Patients underwent weekly resting energy-expenditure measurements. Statistical analysis was performed using analysis of variance with Bonferoni’s correction and Student’s t test where applicable. Results Propranolol treatment reduced heart rates by 10% and significantly improved stroke volume throughout the acute hospital stay compared with controls (P < 0.05). Resting energy expendi- ture was significantly decreased in the propranolol group when compared with controls at discharge (P < 0.05). Infection rates on admission were the same for both groups (17% propranolol vs 22% control). The incidence of infection throughout hospital course was significantly lower in the propranolol group (60%) compared with controls (87%) (P < 0.05). Propranolol significantly increased IGF-I, IGFBP-3, GH, and prealbumin, while it significantly decreased CRP and fatty acids (P < 0.05). Feasibility of the REDOXS study – reducing deaths due to oxidative stress: a randomized pilot trial of glutamine and antioxidant supplementation in critically ill patients Feasibility of the REDOXS study – reducing deaths due to oxidative stress: a randomized pilot trial of glutamine and antioxidant supplementation in critically ill patients Introduction Standard selenium (Se) substitution (30–75 µg/day; 0.4–0.9 µmol/l) in the critically ill is not sufficient for a sustained plasma level (0.58–1.82 µmol/l; 46–143 µg/l). Standard Se substitution keeps the plasma level in the range 0.28–0.42 µmol/l. High-dose Se substitution correlated with a decrease in mortality of patients with SIRS. The influence of high-dose substitution on selected parameters, MAP and mortality in the critically ill were evaluated in a prospective randomized clinical trial. D Heyland, R Dhaliwal, J Muscedere, J Drover, for the Canadian Critical Care Trials Group Kingston General Hospital, Kingston, Canada Critical Care 2007, 11(Suppl 2):P154 (doi: 10.1186/cc5314) Kingston General Hospital, Kingston, Canada Introduction A large randomized trial is needed to evaluate the safety and efficacy of glutamine (GLN) and antioxidant (AOX) supplements. However, high doses of such nutrients via enteral and parenteral routes early in the course of critical illness is often interrupted by high illness acuity and other treatment priorities. The purpose of this pilot trial was to evaluate the feasibility of delivering high-dose GLN and AOX supplements early on in the course of critical illness, and to estimate recruitment for the larger REDOXS study. Methods One hundred and twenty-three patients (78 males, 45 females, median age 62.7 and 60 years, respectively) were randomized into group A (SOFA 19.27) and group B (SOFA 10.23). Group A received standard Se substitution: 30–75 µg NaSelenite i.v./day. Group B received high-dose Se substitution according to a protocol: 1,000 µg at day 1, followed with 500 µg at days 2–14 of NaSelenite i.v. The plasma levels of Se, prealbumin, albumin, CRP, PCT, cholesterol, gluthathionperoxidase GSHPx, D-dimer, creatinine clearance and leucocytes were examined daily. MAP trends and 28-day mortality were evaluated as clinical markers. Methods In six Canadian centers, using a 2 x 2 factorial design, we randomized mechanically ventilated adults who had two or more organ failures within 24 hours of ICU admission to one of four groups: (1) GLN (0.35 g/kg/day i.v. plus 30 g enterally), (2) AOX (500 µg selenium i.v. and 300 µg selenium, 20 mg zinc, 10 mg β-carotene, 500 mg vitamin E, and 1,500 mg vitamin C enterally), (3) both AOX + GLN, and (4) placebo. P155 Effect of high-dose selenium substitution on selected laboratory parameters and prognosis in critically ill patients Effect of high-dose selenium substitution on selected laboratory parameters and prognosis in critically ill patients 1. Delaney HM, Carenevale NH, Garvey JW: Jejunostomy by a needle catheter technique. Surgery 1973, 73:786-945. 2. Braga M, Giannoti L, Radaelli G, et al.: Perioperative immunonutrition in patients undergoing cancer surgery: results of a randomized double-blinded phase 3 trial. Arch Surg 1999, 134:428-433. 3. Moore EE, Jones TN: Benefits of immediate jejunostomy feeding after major abdominal trauma: a prospective ran- domized study. J Trauma 1986, 26:874-881. W Norbury Sh i ’ H Background The aim of this study was to determine the effect of propranolol on infections and clinical parameters during the acute phase postburn. Severe thermal injury is followed by a period of hypermetabolism that is directly proportional to the size of insult sustained. Infection and multiorgan failure are now the leading cause of death from severe thermal injuries. Propranolol, an anticatabolic agent, improves hypermetabolism postburn. However, there is evidence that propranolol worsens immune function and increases the incidence of infection in critically ill patients. Results and discussion Patient recovery was faster in G1. The average patient stay in ICU was 5 ± 1 days (G1) vs 10 ± 2 days (G2). The average hospital stay was 22 ± 3 days (G1) vs 29 ± 5 days. Peristalsis was detected on the third day as an average (G1) vs 4.5 days (G2). A decrease in pulmonary complications was achieved in G1 (one pleural effusion) vs G2 (eight pleural effusions). Laboratory tests show that patients in G1 are in lower catabolism compared with G2 patients. Conclusion Early enteral immunonutrition through jejunostomy is an efficient and safe method of patient nutrition with fewer postoperative complications, and also accounts for a hospital cost decrease of 50%. Results and discussion Patient recovery was faster in G1. The average patient stay in ICU was 5 ± 1 days (G1) vs 10 ± 2 days (G2). The average hospital stay was 22 ± 3 days (G1) vs 29 ± 5 days. Peristalsis was detected on the third day as an average (G1) vs 4.5 days (G2). A decrease in pulmonary complications was achieved in G1 (one pleural effusion) vs G2 (eight pleural effusions). Laboratory tests show that patients in G1 are in lower catabolism compared with G2 patients. Methods Sixty-six patients with burns >40% total body surface area were enrolled into the study and randomized to receive standard burn care (controls, n = 33) or standard burn plus propranolol for more than 21 days (propranolol, 0.5–1.5 mg/kg every 6 hours, n = 33). Biopsies were taken three times a week for microbiological determination. Clinical parameters were collected and blood was drawn at regular intervals throughout the hospital S61 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin P156 P156 Feasibility of the REDOXS study – reducing deaths due to oxidative stress: a randomized pilot trial of glutamine and antioxidant supplementation in critically ill patients Supplementation was continued for a minimum of 5 days up to 28 days and was provided independent of nutrition support. We recorded the time from ICU admission to randomization, the time to start of supplements and nutrition support parameters. Results The Se plasma level was significantly higher in high-dose Se-substituted patients (0.56 µmol/l vs 0.88 µmol/l, P < 0.001). GSHPx was significantly higher in high-dose Se-substituted patients (4,864 U/l vs 6,097 U/l, P < 0.001). No significant differences were found in the level of albumin, prealbumin, CRP, PCT, leucocytes, fibrinogen, cholesterol, D-dimer and creatinine clearance and MAP. The 28-day mortality was lower in a high-dose Se-substituted patients (33% vs 37%), but not significantly. Conclusion The critically ill have an increased demand for Se, which is essential for synthesis of Se enzymes and Se proteins. The increased demand for Se is not covered by standard substitution. High-dose Se substitution (500–1,000 µg/day) normalizes its plasma level and increases the GSHPx plasma level. High-dose Se substitution has no adverse reactions. The decrease of 28-day mortality in high-dose Se-substituted patients is not significant. The trial on high-dose Se substitution further continues. Results From April 2005 to April 2006, 80 patients were randomized (average 2.1/site/month). The median time from ICU admission to randomization was 18.2 hours (range 11.6–21.1 hours). All patients received parenteral supplements, the median (range) time to start was 2.7 hours (2.0–3.8 hours) and 78/80 (98%) received enteral supplements with a median (range) of 2.6 hours (1.9–4.5 hours) from randomization. The mean duration of supplements was 11.1 days (enteral) and 12.2 days (parenteral). The mean volumes of enteral and parenteral supplements received were 84% (range 45–102%) and 93% (range 54–100%) prescribed volumes, respectively. The average prescribed energy and protein intakes were 1,802 kcal/day and 86 g protein/day but the average daily percentage energy and protein received from nutrition support was only 65% (range 4–95%) and 62% (range 2–97%) of that prescribed, respectively. Magnesium deficiency in the surgical intensive care unit W Salem National Cancer Institute, Cairo, Egypt Critical Care 2007, 11(Suppl 2):P156 (doi: 10.1186/cc5316) Available online http://ccforum.com/supplements/11/S2 Methods Sixty adult patients admitted to the ICU after major GIT surgery were enrolled in the study, on the basis of a documented Mg serum level < 0.8 mmol/l on arrival at the ICU. Exclusion criteria were cardiac disease, liver dysfunction or serum creatinine > 1.3. Patients were randomly allocated to one of two groups: the Mg group received 20 mmol (5 g) Mg sulfate, infused daily over 6 hours for 3 days; and a control group received an equivalent amount of 5% dextrose. In the Mg group the next scheduled dose of MgSO4 was held if a serum magnesium level > 1.1 mmol/l, hypotension or bradycardia was recorded. Baseline and daily measurements of serum Mg, potassium, sodium, calcium and creatinine were done. Twenty-four-hour urine collection was used to determine the total urinary excretion of Mg. The net Mg balance (total Mg given – total urine Mg) was calculated. In the Mg group, Mg-deficient patients (retainers) who excreted < 70% of the Mg given ((urine Mg in mmol / daily Mg given) x 100) and Mg nondeficient patients (nonretainers) who excreted > 70% of the total Mg given were recorded. Results One hundred and sixty-six patients were included in this analysis. Among the main results, 63.69% were males and 77.78% were considered malnourished. The mean SOFA score was 6.21, with a mean APACHE II score of 19.39. In total, 97.23% of the PN used in Brazil were manufactured by third-party companies and this was associated with a significant delay in the beginning of the infusion (median time 29.76 hours), and elevated in-ICU (50%) and inhospital (55.17%) mortality rates. A total 24.29% of the patients were immunosuppressed. The most used lipid source was long-chain triglycerides/medium-chain triglycerides (80.69%). Conclusions The use of PN in Brazil is associated with a significant delay in the start of infusion and high mortality rates. The most used lipid emulsion (long-chain triglycerides/medium-chain triglycerides) has been associated with more apoptosis [2] and compromised lymphocyte proliferation [3]. The overall findings of these study indicate that strategies to reduce the delay in start of PN and the use of better lipid sources must be adopted to provide better assistance for patients in need of PN in Brazil. Parenteral nutrition in the intensive care unit: can we deliver better care to our patients? Preliminary results from a multicenter, prospective, cohort study Parenteral nutrition in the intensive care unit: can we deliver better care to our patients? Preliminary results from a multicenter, prospective, cohort study Introduction Ultrasound (US) significantly facilitates central venous catheterization, reducing the percentage of failure, the percentage of accidental arterial puncture, and the percentage of complications (haematoma, haemothorax, pneumothorax). Nonetheless, it is not clear whether US guidance (USG) (so-called ‘dynamic’ or ‘real-time’ US techniques: that is, venipuncture under direct US control) may be better than US assistance (USA) (so- called ‘static’ or ‘indirect’ US techniques: that is, US imaging of the vein, with or without skin marking, and then blind venipuncture). Introduction Ultrasound (US) significantly facilitates central venous catheterization, reducing the percentage of failure, the percentage of accidental arterial puncture, and the percentage of complications (haematoma, haemothorax, pneumothorax). Nonetheless, it is not clear whether US guidance (USG) (so-called ‘dynamic’ or ‘real-time’ US techniques: that is, venipuncture under direct US control) may be better than US assistance (USA) (so- called ‘static’ or ‘indirect’ US techniques: that is, US imaging of the vein, with or without skin marking, and then blind venipuncture). A Pontes-Arruda1, J Teles2, E Silva3, F Machado4, M Baptista Filho5, E Rocha6, C Silva7 1Hospital Fernandes Távora, Fortaleza, Brazil; 2Hospital Português, Salvador, Brazil; 3Hospital Albert Einstein, São Paulo, Brazil; 4Hospital São Paulo – UNIFESP, São Paulo, Brazil; 5Hospital Bandeirantes, São Paulo, Brazil; 6Hospital Copa D’Or, Rio de Janeiro, Brazil; 7Latin American Sepsis Institute, São Paulo, Brazil Critical Care 2007, 11(Suppl 2):P157 (doi: 10.1186/cc5317) Methods From February 2005 to September 2006, our CVC Team adopted the following protocol for internal jugular vein (IJV) catheterization: (a) both IJVs were evaluated to assess position, dimensions, and other features known to affect the risk of catheterization; (b) then, a decision was made whether to continue with USA or USG; (c) the IJV was accessed via the low lateral Jernigan approach; (d) after two failed USA attempts, USG venipuncture was adopted; (d) when IJVs were not available, USG venipuncture of other central veins was the second choice; and (e) fluoroscopy was used only in paediatric patients, but all patients had a postoperative chest X-ray to rule out pneumothorax and malposition. Introduction Nutrition therapy is an integrant aspect of ICU support and can influence outcomes. A delay to starting nutrition support after 24 hours of ICU admission is associated with increased morbidity and mortality [1], and certain lipid emulsions can exacerbate the inflammatory cascade. Available online http://ccforum.com/supplements/11/S2 Results Patients in the Mg group showed a statistically significant increase in mean serum Mg at days 1, 2, and 3 compared with the control group and with day 0 (0.73 ± 0.1, 0.81 ± 0.17, 0.8 ± 0.1, and 0.85 ± 0.11 mmol/l at days 0, 1, 2, and 3, respectively). The mean total amount of Mg given, the mean total urine Mg excretion and the net Mg balance were significantly higher in the Mg group compared with the control group (58 ± 0.17 vs 11.3 ± 2.8 mmol, P > 0.001; 34.0 ± 2.7 vs 15.5 ± 3.8 mmol, P > 0.001; 25.6 ± 1.65 vs 5.2 ± 0.93 mmol, P > 0.001). In the Mg group, the numbers of Mg retainer patients were 24 patients on day 1, 21 on day 2 and nine patients on day 3. Mg nonretainer patients were six patients on day 1, nine on day 2 and 21 patients on day 3. Patients in the Mg group showed better haemodynamic stability and fewer ventricular arrhythmias. Acknowledgement Supported by a research grant from Baxter Hospitalar Ltda. References 1. Simpson F, Doig GS: Parenteral vs. enteral nutrition in the critically ill patient: a meta-analysis of trials using the intention to treat principle. Intensive Care Med 2005, 31: 12-23. 2. Buenestado A, Cortijo J, Sanz M-J, et al.: Olive oil-based lipid emulsion’ s neutral effect on neutrophil functions and leucocyte–endothelial cell interactions. J Parenter Enteral Nutr 2006, 30:286-296. 2. Buenestado A, Cortijo J, Sanz M-J, et al.: Olive oil-based lipid emulsion’ s neutral effect on neutrophil functions and leucocyte–endothelial cell interactions. J Parenter Enteral Nutr 2006, 30:286-296. 3. Cury-Boaventura M, Gorjão R, Martins de Lima T, et al.: Toxic- ity of two lipid emulsions on human lymphocytes and neu- trophils. Crit Care, in press. 3. Cury-Boaventura M, Gorjão R, Martins de Lima T, et al.: Toxic- ity of two lipid emulsions on human lymphocytes and neu- trophils. Crit Care, in press. Conclusion Mg deficiency is common in ICU patients. Mg sulfate administered according to the above regimen is safe. Early treatment of Mg deficiency significantly increased the serum Mg level and provided a better magnesium, potassium and calcium balance, resulting in a shorter ICU stay. P158 Ultrasound-guided vs ultrasound-assisted central venous catheterization Ultrasound-guided vs ultrasound-assisted central venous catheterization M Pittiruti, A LaGreca, G Scoppettuolo, D Sermoneta Catholic University Hospital, Roma, Italy Critical Care 2007, 11(Suppl 2):P158 (doi: 10.1186/cc5318) W Salem Conclusion In critically ill patients with organ failure we provided adequate amounts of study supplements via both enteral and parenteral routes in the early phases of acute illness, independent of nutrition support. We estimated recruitment of at least two patients/site/month for our future trial. Introduction Magnesium (Mg) deficiency is a common and yet underdiagnosed problem. Mg deficiency has been demonstrated in 50% of all ICU patients. These patients have significantly higher morbidity and mortality rate. The aim of this work was to detect the presence of Mg deficiency using a Mg loading test and to evaluate the safety and efficacy of Mg replacement therapy in cancer patients after major gut surgery. Acknowledgements This study was supported by grants from the Canadian Institutes of Health Research and Fresenius-Kabi, Germany. S62 Available online http://ccforum.com/supplements/11/S2 P159 Advantages of ultrasound-guided peripherally inserted venous access (PICC and midline catheters) in critically ill patients M Pittiruti, G Scoppettuolo, A LaGreca Catholic University Hospital, Roma, Italy Critical Care 2007, 11(Suppl 2):P159 (doi: 10.1186/cc5319) Results The central venous catheter placement was successfully performed from the first attempt in both groups. There were no immediate or delayed complications noted; however, the mean time of insertion was longer in the ultrasound-guided group (4.55 min) compared with the external anatomical landmark group (2 min) (Figure 1). Introduction In the critically ill, a reliable peripheral or central venous access is of paramount importance. Nonetheless, access may be difficult or may carry a significant risk of complications (pneumothorax, central line infection, etc.). Peripherally inserted venous catheters – either central (PICC) or peripheral (midline catheters (MC)) – are associated with a low risk of catheter-related bacteremia; also, using the ultrasound guidance and the micro- introducer technique (UG + MIT), they can be inserted in any patient, regardless of the availability of superficial veins. Discussion Some studies have been designed to evaluate ultrasound-guided central venous catheter placement compared with the conventional method based on external anatomical landmarks. These studies demonstrated the superiority of ultrasound-guided central venous line placement over the external anatomical landmark technique. However, there was no time gain demonstrated in ultrasound-guided placement [2]. On the other hand, a number of studies have expressed several reservations concerning the systematic use of ultrasound guidance for central line placement [3]. In our patients we found that the use of ultrasound neither altered the rate of complication nor the number of attempts in central venous catheter placement. Also the duration of placement of the central line catheter using the external We have reviewed our experience of 56 peripherally inserted catheters in 53 patients in different ICUs (surgical ICU, trauma unit, coronary unit, neurosurgical ICU, stroke unit, pediatric ICU, etc.); all catheters were positioned at the mid-arm, in the basilic vein or in the brachial veins, using UG + MIT. We assessed the feasibility of this technique in the acutely ill and the rate of complications. Methods and results We inserted 16 PICC and 40 MC in patients requiring prolonged venous access (estimated >15 days); nine were septic, six had coagulopathy, 21 had tracheostomy. We used both silicone and polyurethane 4 Fr catheters. Procedures were performed by a team of trained physicians and nurses. Parenteral nutrition in the intensive care unit: can we deliver better care to our patients? Preliminary results from a multicenter, prospective, cohort study For an appropriate evaluation of the impact of these and other recent research findings, information regarding the use of parenteral nutrition (PN) in the ICU is needed. Introduction Nutrition therapy is an integrant aspect of ICU support and can influence outcomes. A delay to starting nutrition support after 24 hours of ICU admission is associated with increased morbidity and mortality [1], and certain lipid emulsions can exacerbate the inflammatory cascade. For an appropriate evaluation of the impact of these and other recent research findings, information regarding the use of parenteral nutrition (PN) in the ICU is needed. Methods This is the interim analysis of a multicenter, prospective, cohort study aimed to obtain information regarding the use of PN. Data were collected during 3 months from ICU patients over 18 years of age on the use of PN in 20 adult ICUs in Brazil using a web-based clinical research form. S63 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin P160 average 5.5 years: 20 short-term + 84 tunnelled + two ports). In adults, the procedure started as USA in 522 and as USG in 299 cases: a shift from USA to USG was necessary in 8%. USG was the first choice in all paediatric cases. The IJV was successfully cannulated in most adult patients, with very few exceptions (innominate vein in 12 cases, axillary vein in two cases, femoral vein in one case, all by USG). In one paediatric patient, the CVC was inserted in the subclavian vein, via a supraclavicular USG approach. Complications were: failure 0%; pneumothorax 0%; haemothorax 0%; accidental arterial puncture 1.1% (1.7% USA vs 0.3% USG); haematoma 0.4% (only for USA); malposition (0.8%, exclusively with the left IJV). P159 Catheter insertion was easy in most cases, and immediate complications were few (no failure; one hematoma; no arterial or nerve injury). Late complications were: one local infection; three thrombosis (two requiring removal); four cases of damage of the external catheter (due to poor nursing or to inappropriate use of the catheter during rx procedures), all easily repaired; one dislocation; no catheter occlusion; no catheter-related bacteremia. Most catheters stayed in place for a prolonged time (range 9–65 days, median 19 days); only three were removed because of complications. A comparison between ultrasound-guided central venous line placement and an anatomical landmark technique M Soliman, K Ismail Department of Anaesthesia & Intensive Care Medicine, The Mid Yorkshire Hospitals, UK Critical Care 2007, 11(Suppl 2):P160 (doi: 10.1186/cc5320) Introduction Ultrasound has been introduced in the insertion of central venous lines to reduce the complications associated with the conventional landmark technique [1]. We compared both techniques; we noted the number of attempts, the duration of insertion and complications. Conclusion In conclusion, (a) we had a minimal incidence of complications, (b) USG was associated with a relevant reduction of the risk of accidental arterial puncture and haematoma, if compared with USA, and (c) choosing the left IJV was associated with a higher risk of malposition. Methods Thirty patients were randomly selected, from the operating theatre and ICU, who required placement of a central venous catheter. The central venous catheter placement was performed by two experienced anaesthetists with more than 6 years experience in anaesthesia and intensive care. In 15 patients the internal jugular venous catheter placement was performed using the external anatomical landmark technique, and in the other 15 patients the placement was under ultrasound guidance. The duration of insertion was recorded from the moment the needle touched the skin until insertion of the catheter and removal of the guide wire. The numbers of attempts as well as immediate or delayed complications were recorded. P161 Results Out of 67 surgeries contacted, we achieved a response rate of 65%. Thirty-three practices (49%) were able to provide complete data, six (9%) provided partial data, and a further five (7%) were unable or unwilling to provide any data. Twenty-three (34%) practices did not respond. A total of 318,130 patients were listed by the responding practices. Of these: 23 patients live with long-term tracheostomies, a prevalence of 1 in 13,800; 65 patients receive mechanical respiratory support at home, a prevalence of 1 in 4,900; and 207 patients receive oxygen therapy at home, a prevalence of 1 in 1,500. P162 Thirty-three practices (49%) were able to provide complete data, six (9%) provided partial data, and a further five (7%) were unable or unwilling to provide any data. Twenty-three (34%) practices did not respond. A total of 318,130 patients were listed by the responding practices. Of these: 23 patients live with long-term tracheostomies, a prevalence of 1 in 13,800; 65 patients receive mechanical respiratory support at home, a prevalence of 1 in 4,900; and 207 patients receive oxygen therapy at home, a prevalence of 1 in 1,500. Method A postal survey was sent out to practice managers in the local catchment area. They were asked to provide data for: patients on home ventilatory support for any reason, patients with long-term tracheostomies, patients with COPD who are on home oxygen or who you would classify as end stage, and the total number of patients registered to the practice. This was followed up with a telephone call approximately 2 weeks later. Many were then e- mailed the same questionnaire. A further two telephone calls to each practice were made as necessary in order to obtain data. 3. Martin MJ, Hussain, Piesman M, et al.: Is routine ultrasound guidance for central line placement beneficial? A prospec- tive analysis. Curr Surg 2004, 61:71-74. 3. Martin MJ, Hussain, Piesman M, et al.: Is routine ultrasound guidance for central line placement beneficial? A prospec- tive analysis. Curr Surg 2004, 61:71-74. Figure 1 (abstract P160) Figure 1 (abstract P160) Conclusion Our experience with PICC and MC was characterized by an extremely low rate of infective and thrombotic complications. Venous access was achieved in any patient, even with limited availability of peripheral veins. The use of US-inserted PICC and MC should be considered when central access is not advisable or is contraindicated. S64 Available online http://ccforum.com/supplements/11/S2 P162 Prevalence of respiratory support in the community – the Surrey experience S Burfield, L Sherrard-Smith, E Laitt, V Jamison, W Jewsbury, S Pambakian Frimley Park Hospital NHS Foundation Trust, Surrey, UK Critical Care 2007, 11(Suppl 2):P162 (doi: 10.1186/cc5322) P162 anatomical landmark technique was shorter than in the ultrasound- guided method. P162 Prevalence of respiratory support in the community – the Surrey experience Conclusion The external anatomical landmark technique in central line placement is considered a safe method with experienced hands. The time of insertion of a central line using the external anatomical landmark technique was shorter than the ultrasound- guided placement method. It is essential for all trainees to be taught both methods for central line placement to be able to place a central line catheter quickly and safely in emergency situations and when an ultrasound machine is not available. S Burfield, L Sherrard-Smith, E Laitt, V Jamison, W Jewsbury, S Pambakian Frimley Park Hospital NHS Foundation Trust, Surrey, UK Critical Care 2007, 11(Suppl 2):P162 (doi: 10.1186/cc5322) Introduction This study aimed to establish the prevalence of home ventilatory and respiratory support within the catchment area of Frimley Park Hospital in Surrey. The number of patients receiving respiratory support at home has been increasing nationally since 1990 [1]; however, no local data exist. This trend is likely to continue as domiciliary ventilation gains popularity for the treatment of obstructive sleep apnoea and certain groups of COPD patients [2]. 1. Denys BG, Uretsky BF, Reddy PS: Ultrasound-assisted can- nulation of the internal jugular vein. A prospective com- parison to the external landmark-guided technique. Circulation 1993; 87:1557-1562. 2. Randolph AG, Cook DJ, Gonzales CA, Pribble CG: Ultra- sound guidance for placement of central venous catheters: a meta-analysis of the literature. Crit Care Med 1996, 24:2053-2058. 2. Randolph AG, Cook DJ, Gonzales CA, Pribble CG: Ultra- sound guidance for placement of central venous catheters: a meta-analysis of the literature. Crit Care Med 1996, 24:2053-2058. Method A postal survey was sent out to practice managers in the local catchment area. They were asked to provide data for: patients on home ventilatory support for any reason, patients with long-term tracheostomies, patients with COPD who are on home oxygen or who you would classify as end stage, and the total number of patients registered to the practice. This was followed up with a telephone call approximately 2 weeks later. Many were then e- mailed the same questionnaire. A further two telephone calls to each practice were made as necessary in order to obtain data. Results Out of 67 surgeries contacted, we achieved a response rate of 65%. References References Data presented as the mean ± SE after 120 minutes of isolated lung perfusion. Continuous assessment of inspiratory resistive work during different types of pulmonary oedema in isolated rat lungs Continuous assessment of inspiratory resistive work during different types of pulmonary oedema in isolated rat lungs Y Cikirikcioglu, D Morel University Medical Centre, Geneva, Switzerland Critical Care 2007, 11(Suppl 2):P161 (doi: 10.1186/cc5321) We recently demonstrated in isolated blood perfused rat lungs subjected to i.t. LPS-induced pulmonary oedema that the continuous measurement of inspiratory resistive work is a good indirect indicator of progressive lung oedema [1]. Here we extend these findings to two other types of pulmonary oedema: hydrostatic oedema induced by elevation of the left atrial pressure, and alveolar oedema (ALV) by infusing normal saline into the trachea at two different infusion rates (2 and 4 ml/hour for 120 min). Discussion This study suggests that the Frimley Park Hospital population of 350,000 currently contains about 100 individuals requiring mechanical respiratory support at home. This is of concern as currently there is no formal support for any of these high-risk patients other than ventilator maintenance. Simple problems precipitate hospital admission and rapidly trigger outreach or intensive care review. The current position is clearly unsatisfactory and must be addressed by PCTs if patient numbers increase. See Table 1. Our results indicate that the continuous measurement of inspiratory resistive work is a good indicator of both permeability and hydrostatic lung oedema, but not of pure alveolar oedema (absence of interstitial oedema). References P163 Intensive care unit patients on mechanical ventilation at a university hospital in southern Brazil: characteristics, mortality, frequency, and mortality risk factors pulmonary mechanics, CO2 homeostasis and pulmonary gas exchanges with less frequent ventilatory settings (tidal volume (TV), respiratory rate (RR)) and lower peak inspiratory pressure (Ppeak) and plateau pressure (Pplat) than pressure-controlled synchronised intermittent mandatory ventilation (P-SIMV) in patients undergoing laparocopic cholecystectomy (LP). L Fialkow1, R Sens1, L Sehn1, R Cardoso1, A Wolmeister1, A Milani1, M Bozzetti2, S Vieira1, J Brauner1, A Guntzel1, M Ficanha1, G Machado1 1Hospital de Clínicas de Porto Alegre, Brazil; 2FAMED-UFRGS, Porto Alegre, Brazil Critical Care 2007, 11(Suppl 2):P163 (doi: 10.1186/cc5323) Method The study group consisted of 40 patients (APV-SIMV n = 20, P-SIMV n = 20). LP was performed under total intravenous anesthesia. After induction of anesthesia, a RR of 12 breaths/ minute, and an inspiratory:expiratory rate of 1:2 and PEEP of 6 cmH2O were set for both groups. APV-SIMV was started with a target TV of 8 ml/kg. P-SIMV was started with the inspiratory pressure (Pins) that will provide 8 ml/kg TV. The settings were changed until target parameters to maintain normocapnia and normoxia were achieved (ETCO2 30–35 mmHg, PaCO2 35–45 mmHg and SaO2 >90%). When the target parameters could not be achieved, the first RR was increased by 2 breaths/ minute up to 16 breaths/minute, then the volume or pressure was titrated to induce 1 ml/kg increases in TV up to 10 ml/kg. The initial FiO2 was set to 50%. FiO2 was increased with increments when the SaO2 fell below 90%. PaO2/FiO2, static compliance, VD/VT, Ppeak and Pplat, ETCO2, inspiratory and expiratory resistances, and arterial blood gas analysis were recorded before, during and after pneumoperitoneum. Statistical analysis were carried out using the chi-square test, paired test and independent samples test when appropriate. Introduction Acute respiratory failure (ARF) is a frequent cause of admission to ICUs and frequently necessitates mechanical ventilation (MV). Knowledge about the frequency and risk factors associated with requirements for MV is crucial to improve outcomes. The objectives of our study were to determine the characteristics, frequency of MV, overall and specific mortality rates and mortality risk factors in patients who required MV in the ICU of a general university hospital in southern Brazil. Methods A prospective cohort of 751 adult patients admitted to the ICU who needed MV for at least 24 hours, between March 2004 and July 2006. P163 Intensive care unit patients on mechanical ventilation at a university hospital in southern Brazil: characteristics, mortality, frequency, and mortality risk factors Data were collected on each patient at the inclusion in the study and on a daily basis, during the course of MV for up to 28 days. Results The frequency of MV was 30%; the overall and specific mortality rates were 15% and 50%, respectively. The mean (±SD) age was 57 ± 21 years; 52% were males; the mean APACHE II score was 22.2 ± 8.2; 69% were medical patients; the mean duration of MV was 11 ± 7.9 days; 93% were on invasive MV. A multivariable analysis was performed to identify the variables associated with death. These included sepsis (P = 0.02), MV duration (P < 0.001), renal failure (P = 0.006) prior to MV, and the following variables that occurred during the MV period: sepsis (P = 0.004), acute lung injury/acute respiratory distress syndrome (P = 0.001), renal failure (P < 0.001), haematological failure (P = 0.02) and vasoactive drug use (P < 0.001). It should be noted that selected ventilatory monitored variables were included in the multivariate model. However, they were not associated with mortality in our study sample. Results Demographic data were similar between groups. Pneumoperitoneum caused significant decreases in static compliance and arterial pH, and increases in Ppeak and Pplat, VD/VT and ETCO2 in both groups. However, APV-SIMV resulted in fewer setting changes, lower peak and plateau pressures, VD/VT, and ETCO2 levels when compared with P-SIMV (P < 0.025). Conclusion APV-SIMV may provide better results then conventional P-SIMV in patients undergoing LP. P165 The influence of cycling-off criteria and pressure support slope on the respiratory and hemodynamic variables in intensive care unit patients T Correa, R Passos, S Kanda, C Tanigushi, C Hoelz, J Bastos, G Janot, E Meyer, C Barbas Hospital Israelita Albert Einstein, São Paulo, Brazil Critical Care 2007, 11(Suppl 2):P165 (doi: 10.1186/cc5325) Conclusions Our results indicate a frequency of patients on MV of 30% with an elevated specific mortality rate (50%). Sepsis, MV duration, renal failure prior to MV, and sepsis, acute lung injury/acute respiratory distress syndrome, renal failure, haematological failure and vasoactive drug use during the MV period are risk factors for mortality in 28 days after starting MV. Identification of these factors may allow early interventions to attempt to mitigate these poor outcomes. Introduction Modern mechanical ventilators allow changes in the flow cycling-off criteria and the pressure slope during pressure support ventilation (PSV). Changes in the cycling-off flow criteria of PSV can modify the expiratory synchrony between the mechanical and neural inspiration termination. The influences of the slope changes on the respiratory parameters in ICU patients are still under investigation. Reference 1. Simonds A: Eur Respir J 2003, Suppl 47:38s-46s. 1. Cikirikcioglu Y, Morel D: Eur Respir J 2006, 28:345s. 2. Consensus conference report. Chest 1999, 116:521-534. Table 1 (abstract P161) Dynamic lung compliance Weight gain Inspiratory resistive work (ml/cmH2O) (g) Wet/dry lung weight ratio (ml x cmH2O) Control (n = 6) 0.35 ± 0.06 0.54 ± 0.21 6.37 ± 0.35 0.98 ± 0.35 LPS (n = 12) 0.28 ± 0.02 4.63 ± 0.63 8.92 ± 0.21 10.45 ± 1.15 Hydrostatic (n = 7) 0.38 ± 0.06 1.97 ± 0.24 6.46 ± 0.33 1.65 ± 0.54 ALV 2 ml/hour (n = 6) 0.24 ± 0.04 2.66 ± 0.14 10.22 ± 0.60 –1.09 ± 0.54 ALV 4 ml/hour (n = 4) 0.07 ± 0.02 3.74 ± 0.79 9.08 ± 0.94 0.96 ± 1.13 Data presented as the mean ± SE after 120 minutes of isolated lung perfusion. S65 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Figure 1 (abstract P166) Figure 1 (abstract P166) Minute volume/etCO2 relationship. P164 The effects of adaptive pressure ventilation–synchronised intermittent mandatory ventilation and pressure-controlled synchronised intermittent mandatory ventilation on pulmonary mechanics and arterial gas analyses during laparoscopic cholecystectomy Objectives To compare the effects of two different flow cycling-off criteria and the effects of two different pressure slopes (150 ms or 300 ms) of PSV on the respiratory parameters of ICU mechanically ventilated patients. M Akbaba, M Tulunay, O Can, Z Alanoglu, S Yalcin Ankara University Medical Faculty, Ankara, Turkey Critical Care 2007, 11(Suppl 2):P164 (doi: 10.1186/cc5324) Methods We prospectively evaluated 20 intubated and mechanically ventilated adult ICU patients recovering from acute respiratory failure who could be comfortably ventilated on pressure support mode (PSV) with pressure support of 15 cmH2O, PEEP of 5 cmH2O and FIO2 of 40%. Patients were ventilated on PSV, with 25% and 40% of peak expiratory flow cycling criteria, and were submitted to 150 ms and 300 ms pressure slope delay. We evaluated the respiratory rate, expiratory tidal volume, minute ventilation, VCO2, VTCO2, ETCO2, mean arterial pressure (MAP), heart rate and SpO2. Background Hypercapnia and elevated intraabdominal pressure from carbon dioxide (CO2) pneumoperitoneum can adversely affect respiratory mechanics and arterial blood gases. We tested the hypothesis that adaptive pressure ventilation–synchronised intermittent mandatory ventilation (APV-SIMV) may provide better S66 Available online http://ccforum.com/supplements/11/S2 Table 1 (abstract P165) Table 1 (abstract P165) Respiratory Tidal Minute volume Slope Heart rate SpO2 Cycling-off (%) rate volume (ml) (l/min) VCO2 VTCO2 ETCO2 MAP 0.15 83.4 98.8 25 18.2 587.5 10.6 193.6 11.2 27.8 96.4 0.15 83.9 98.8 40 19.2 560.7 10.0 183.7 10.88 28 96.2 0.30 83.6 98.7 25 19.4 588.4 10.5 192.8 11.54 28 98.2 0.30 83.6 98.9 40 19.7 565.2 10.2 187.8 10.61 28.2 97.7 Figure 2 (abstract P166) Parametric fit of etCO2 data. Figure 2 (abstract P166) Parametric fit of etCO2 data. Figure 2 (abstract P166) Results Comparisons between different slope and cycling-off values did not result in any statistically significant changes for the evaluated variables (Table 1). Conclusion Changes in cycling-off criteria from 25% to 40% of the peak flow and on the pressure slope from 150 ms to 300 ms do not affect other respiratory and hemodynamic variables in mechanically ventilated patients. P167 The impact of noninvasive versus invasive mechanical ventilatory support on survival in hematological patients with acute respiratory failure AUTOPILOT-BT: an approach towards automatic mechanical ventilation AUTOPILOT-BT: an approach towards automatic mechanical ventilation AUTOPILOT-BT: an approach towards automatic mechanical ventilation S Lozano1, K Moeller1, C Stahl2, J Guttmann2 1Furtwangen University, Villingen-Schwenningen, Germany; 2University of Freiburg, Germany Critical Care 2007, 11(Suppl 2):P166 (doi: 10.1186/cc5326) Parametric fit of etCO2 data. Introduction The clinical use of ventilators is limited due to a huge variety of different ventilation methods. The clinician – often under high cognitive load from the complicated technical equipment on an ICU – just uses a small subset of available parameter settings. The aim of the present study was to develop a closed-loop ventilation controller based on mathematical models and fuzzy logic. evaluating, for example, the etCO2 data. The course of etCO2 following the setting of optimal frequency was evaluated to calculate the time required for equilibration of etCO2. Results A module automating the initial settings of the ventilator according to local ICU rules is realized. Modules were added that optimize breathing frequency with respect to PaCO2/etCO2 and FiO2 according to SO2 whenever no PaO2 is available. A lung simulator (Michigan Instruments Inc., Grand Rapids, MI, USA) connected with the LS4000 (Dräger Medical) was used to evaluate the system. Exemplary results are presented in the figures, which show the minute volume/etCO2 relationship (Figure 1) and a parametric fit of etCO2 data (Figure 2). The adjustment of the frequency is based on the current etCO2 model. Methods The system was designed to track a desired end-tidal CO2 pressure (PaCO2), to find a PEEP leading to maximum estimated respiratory system compliance and to maintain the arterial oxygen saturation (SaO2) at an optimal level. We developed a program in LabView (National Instruments, Austin, TX, USA) on a laptop that is able to read the internal data of a ventilator (Evita 4; Dräger Medical, Germany) in real time. Respiratory signals (for example, SaO2) are acquired from monitoring. Discrete measure- ments (for example, PaO2) are either assumed constant until next measurement or are interpolated using a model-based approach Conclusion Automation is a ‘sine qua non’ to achieve optimal patient individualized ventilation support. Our system is enabled to evaluate a therapeutic strategy and to base the settings of the ventilator on current trends/drifts observed in the data. The impact of noninvasive versus invasive mechanical ventilatory support on survival in hematological patients with acute respiratory failure P168 Physiological variables predictive of survival in patients with acute type II respiratory failure on noninvasive ventilation N Salahuddin, M Naeem, S Khan Aga Khan University & Hospital, Karachi, Pakistan Critical Care 2007, 11(Suppl 2):P168 (doi: 10.1186/cc5328) Introduction There are very few data available from the Indian subcontinent regarding the use of noninvasive ventilation (NIV). We carried out this study to determine variables that could be used in the emergency room to predict survival in patients placed on NIV. Methods This was a prospective observational cohort study statistically significant difference between the baseline characteristics of the groups that survived or died. The overall survival rate for patients placed on NIV was 76.5%, the intubation rate was 12.6% and the length of hospitalization was 11.4 days (±10.9). Statistically significant improvements in pH and PaCO2 occurred at 24 hours and 48 hours of NIV usage compared with Figure 1 (abstract P167) Figure 1 (abstract P168) Figure 2 (abstract P168) Figure 1 (abstract P167) Figure 1 (abstract P168) Figure 1 (abstract P167) Figure 1 (abstract P168) Figure 1 (abstract P168) Figure 1 (abstract P167) Figure 1 (abstract P167) Figure 2 (abstract P168) Figure 2 (abstract P168) 62.5%, respectively (P = 0.99), but SAPS II at ICU admission was lower in NIPPV patients (45 ± 15 vs 60 ± 18, P < 0.001). NIPPV was the sole mode of ventilation in 15 patients and was followed by IPPV in 41 patients (NIPPV–IPPV). ICU mortality in sole NIPPV patients was 35% compared with 76% in NIPPV–IPPV patients. In a multivariable analysis, the ICU mortality of ventilated patients was associated with SAPS II at admission (OR 1.029, CI 1.009–1.048, P = 0.003), NIPPV–IPPV (OR 2.73, CI 1.1–6.8, P = 0.03), and bacterial infection (OR 0.39; CI 0.21–0.73, P = 0.003). The mean change of SOFA between day 1 and day 5 was 0 (±2.6) in NIPPV patients (n = 33) compared with –1.6 (±4.3) in IPPV patients (n = 87) (P = 0.001) surviving beyond 5 days of ICU admission (Figure 1). Conclusion NIPPV was not associated with better outcome in our population of hematological patients with acute respiratory failure. NIPPV followed by IPPV was an independent predictor of mortality. P168 Physiological variables predictive of survival in patients with acute type II respiratory failure on noninvasive ventilation N Salahuddin, M Naeem, S Khan Aga Khan University & Hospital, Karachi, Pakistan Critical Care 2007, 11(Suppl 2):P168 (doi: 10.1186/cc5328) N Salahuddin, M Naeem, S Khan Aga Khan University & Hospital, Karachi, Pakistan Critical Care 2007, 11(Suppl 2):P168 (doi: 10.1186/cc5328) statistically significant difference between the baseline characteristics of the groups that survived or died. The overall survival rate for patients placed on NIV was 76.5%, the intubation rate was 12.6% and the length of hospitalization was 11.4 days (±10.9). Statistically significant improvements in pH and PaCO2 occurred at 24 hours and 48 hours of NIV usage, compared with baseline (7.28 vs 7.37, P < 0.001; 74.2 vs 65.4, P = 0.003) (Figures 1 and 2). There was no significant change in PaO2. The variables predicting survival were age (62.1 ± 12.5 years, 67.8 ± 8.7 years, P = 0.025), serum creatinine (1.1 ± 0.5 mg/dl, 1.7 ± 0.8 mg/dl, P = 0.002), pH at baseline (7.31 ± 0.09, 7.25 ± 0.9, P = 0.005), HCO3 at baseline (36.1 ± 7.5 mEq/l, 32.4 ± 9.3 mEq/l, P = 0.032), pH at 48 hours (7.39 ± 0.07, 7.33 ± 0.06, P = 0.002), and need for endotracheal intubation (10%, 21%, P < 0.05). Introduction There are very few data available from the Indian subcontinent regarding the use of noninvasive ventilation (NIV). We carried out this study to determine variables that could be used in the emergency room to predict survival in patients placed on NIV. Methods This was a prospective, observational cohort study carried out from 2001 to 2005 on all patients presenting with acute type II respiratory failure and meeting criteria for NIV use. NIV was started in the emergency room at settings that were titrated according to arterial blood gases. Univariate and multivariate regression analysis was used to determine the effect on survival. P < 0.05 was considered statistically significant. The software used was SPSS 11. Results The total number of patients enrolled was 119; 52.9% were males, 47.1% were females. The mean age was 63.3 years (±11.9). The most common cause of respiratory failure was COPD in 91.6%. A total of 56.3% patients were stuporus at presentation, and 7.5% fulfilled criteria for severe sepsis. There was no Conclusion NIV improves outcomes in our setting. The impact of noninvasive versus invasive mechanical ventilatory support on survival in hematological patients with acute respiratory failure P Depuydt, D Benoit, C Roosens, O Fritz, L Noens, J Decruyenaere Ghent University Hospital, Ghent, Belgium Critical Care 2007, 11(Suppl 2):P167 (doi: 10.1186/cc5327) Objective To assess the impact on ICU survival of noninvasive (NIPPV) versus invasive mechanical ventilation (IPPV) as the initial ventilatory mode in hematological patients with acute respiratory failure. Design A retrospective evaluation of a prospectively followed cohort of 277 hematological patients ventilated at the ICU of a tertiary care hospital between January 1997 and June 2006. Design A retrospective evaluation of a prospectively followed cohort of 277 hematological patients ventilated at the ICU of a tertiary care hospital between January 1997 and June 2006. Results NIPPV was the initial ventilatory mode in 56 patients. ICU mortality in patients with initial NIPPV versus IPPV was 62.9% and Minute volume/etCO2 relationship. Results NIPPV was the initial ventilatory mode in 56 patients. ICU mortality in patients with initial NIPPV versus IPPV was 62.9% and S67 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine Figure 1 (abstract P168) Figure 2 (abstract P168) 62.5%, respectively (P = 0.99), but SAPS II at ICU admission was lower in NIPPV patients (45 ± 15 vs 60 ± 18, P < 0.001). NIPPV was the sole mode of ventilation in 15 patients and was followed by IPPV in 41 patients (NIPPV–IPPV). ICU mortality in sole NIPPV patients was 35% compared with 76% in NIPPV–IPPV patients. In a multivariable analysis, the ICU mortality of ventilated patients was associated with SAPS II at admission (OR 1.029, CI 1.009–1.048, P = 0.003), NIPPV–IPPV (OR 2.73, CI 1.1–6.8, P = 0.03), and bacterial infection (OR 0.39; CI 0.21–0.73, P = 0.003). The mean change of SOFA between day 1 and day 5 was 0 (±2.6) in NIPPV patients (n = 33) compared with –1.6 (±4.3) in IPPV patients (n = 87) (P = 0.001) surviving beyond 5 days of ICU admission (Figure 1). Conclusion NIPPV was not associated with better outcome in our population of hematological patients with acute respiratory failure. NIPPV followed by IPPV was an independent predictor of mortality. P170 Methods This was a blinded, observational cohort trial that was approved by the Henry Ford Hospital Institutional Review Board. Henry Ford Hospital is an urban, tertiary institution in Detroit, Michigan with an emergency department census of 95,000 patient visits per year. Inclusion criteria: patients > 18 years of age triaged to Cat 1 with acute respiratory distress and for whom the decision to intubate, use NIV or discharge the patient had not been decided. Exclusion criteria: immediate intubation, NIV, or discharge from Cat 1. Baseline demographics and vital signs were collected prior to the initiation of the trial (Figure 1). The CO2SMO Plus! with the ETCO2/flow sensor was used for obtaining bedside measurements. Patients would breathe through the ETCO2/flow sensor for 60 seconds with nose clips. Is threshold useful in accelerating weaning from mechanical ventilation? S Vieira1, R Condessa1, J Brauner1, A Saul1, A Silva1, M Silva1, L Borges2, M Moura1, M Alves1, F Kutchak1, L Biz1, C Dieterich1 1Hospital de Clínicas de Porto Alegre, Brazil; 2Hospital Moinhos de Vento, Porto Alegre, Brazil Critical Care 2007, 11(Suppl 2):P170 (doi: 10.1186/cc5330) Introduction Threshold can be used as a physiotherapic tool in order to increase muscle strength, and this effect can be useful in weaning patients. However, there are still controversies considering its advantages during weaning from mechanical ventilation (MV). The goal of this study is to evaluate its effects in such a situation. Results The threshold value for RSBI that discriminated best between no NIV and the need for NIV was determined in 61 patients. Thirty-five patients who did not require ventilatory support had a mean RSBI of 105, and 26 patients with NIV had a mean RSBI of 222 (P = 0.0001). A receiver-operating-characteristic curve was constructed based upon the dataset in increments of 10 for the RSBI (Figure 2). An RSBI > 120 yielded a sensitivity of 0.81 and a specificity of 0.74 for determining the need for NIV. A likelihood ratio positive (LR+) of 3.14 further illustrates the formidable predictive value of the 120 RSBI. Methods Patients under MV for more than 48 hours and prone to weaning were studied. They were randomized to the control group or to the threshold group and followed daily until extubation, tracheostomy or death. The threshold group was trained twice daily. All cardiorespiratory variables, maximal inspiratory (PImax) and expiratory (PEmax) pressures were registered twice daily during the observation period. P169 P169 Rapid shallow breathing index – a key predictor for noninvasive ventilation Rapid shallow breathing index – a key predictor for noninvasive ventilation J Crawford1, R Otero1, M Donnino2, J Garcia1, R Khazal1, T Lenoir1 1Henry Ford Hospital, Detroit, MI, USA; 2Beth Israel Deaconess Medical Center, Boston, MA, USA Critical Care 2007, 11(Suppl 2):P169 (doi: 10.1186/cc5329) Introduction The rapid shallow breathing index (RSBI) is the ratio determined by the frequency (f) divided by the tidal volume (VT). An RSBI <105 has been widely accepted by healthcare professionals as a criteria for weaning to extubation and has been integrated into most mechanical ventilation weaning protocols. We hypothesized that the converse of using the RSBI for weaning might be useful in predicting the need for noninvasive ventilation. Advancements in technology have made it easier to accurately attain bedside RSBI measurements. The purpose of this study was to ascertain a threshold value of RSBI that could predict the need for noninvasive ventilation (NIV) in patients presenting with acute respiratory distress to the critical care area (Cat 1) in the emergency department. Conclusion A RSBI of 120 or greater, as reflected by f/VT ratio, may be a predictor of when NIV support should be considered. Further prospective randomized studies are needed to validate the value of 120. Conclusion A RSBI of 120 or greater, as reflected by f/VT ratio, may be a predictor of when NIV support should be considered. Further prospective randomized studies are needed to validate the value of 120. P170 The length of weaning and success or failure were registered. Variables were compared by analysis of variance, Mann–Whitney U test and the chi-square test. Results are shown as the median, mean and standard deviation or as percentages. The significance level was P < 0.05. P168 Physiological variables and the need for intubation can predict an improved survival in these patients. S68 Available online http://ccforum.com/supplements/11/S2 Conclusion A RSBI of 120 or greater, as reflected by f/VT ratio, may be a predictor of when NIV support should be considered. Further prospective randomized studies are needed to validate the value of 120. Figure 2 (abstract P169) Figure 2 (abstract P169) Application of treatment bundles reduces days on mechanical ventilation in critically ill patients Methods A total of 104 patients who had been ventilated for more than 48 hours in the postoperative period from October 2005 to October 2006 were enrolled in the study. After fulfilling the weaning checklist they were randomly assigned into two groups: SIMV+PSV group (n = 53), and ITSB group (n = 51). In patients assigned to the SIMV+PSV group, the ventilator rate was initially set at 6–8 breaths/minute plus PSV of 15 cmH2O and then both reduced, if possible, by 2 breaths/minute and 2 cmH2O each time. Patients able to maintain adequate ventilation with SIMV of 2 breaths/minute and PSV of 5 cmH2O for at least 2 hours without signs of distress were extubated. Patients assigned to the ITSB group were disconnected from the ventilator and allowed to breathe spontaneously through a T-tube circuit. The duration of the trials was gradually increased. Between the trials, assist–control ventilation was provided for at least 1 hour. Patients able to breathe on their own for at least 2 hours without signs of distress were extubated. F Bloos1, S Müller1, A Harz1, M Gugel1, D Geil1, K Reinhart2, G Marx2 1University Hospital Jena, Germany; 2Friedrich-Schiller University Jena, Germany Critical Care 2007, 11(Suppl 2):P171 (doi: 10.1186/cc5331) Background Reduction of time on the ventilator is a key concept to avoid complications. Recommendations include semirecumbent positioning (SRP) [1], low tidal volume ventilation (TV = 6 ml/kg) [2], prophylaxis for stress ulcer (SUP) [3], and deep vein thrombosis (DVTP) [4]. The goal of this study was to investigate whether staff training about these treatments decreases days on ventilation. Methods All patients of a 50-bed ICU with mechanical ventilation >24 hours were included. From June 2005 to September 2005 (Audit I), patients were examined daily for SRP >30°, low tidal volume ventilation, DVTP, and SUP by an independent task force. Afterwards, nurses and physicians were trained for the monitored treatments. Audit II was then performed from March 2006 to June 2006. Results Until the first attempt was made for weaning, all patients received assist–control ventilation because of haemodynamic instability. The following underlying conditions were present: chronic obstructive pulmonary disease in 67 patients, neuromuscular disorders in nine patients, acute lung injury as a result of surgery in 14 patients, asthma in six patients and miscellaneous causes in eight patients. P173 P173 Predicting successful weaning in a cohort of elderly patients C Corbellini, A Guntzel, C Trevisan, S Vieira Hospital de Clinicas de Porto Alegre, Brazil Critical Care 2007, 11(Suppl 2):P173 (doi: 10.1186/cc5333) Predicting successful weaning in a cohort of elderly patients Conclusion SRP could be successfully improved by staff training. Enhanced implementation was associated with reduction in days on ventilation. C Corbellini, A Guntzel, C Trevisan, S Vieira Hospital de Clinicas de Porto Alegre, Brazil Critical Care 2007, 11(Suppl 2):P173 (doi: 10.1186/cc5333) References 1. Drakulovic MB: Lancet 1999, 354:1851. 2. Amato MB: N Engl J Med 1998, 338:347. 3. Cash BD: Crit Care Med 2002, 30:S373. 4. Samama MM: N Engl J Med 1999, 341:793. 1. Drakulovic MB: Lancet 1999, 354:1851. 2. Amato MB: N Engl J Med 1998, 338:347. 3. Cash BD: Crit Care Med 2002, 30:S373. 4. Samama MM: N Engl J Med 1999, 341:793. 1. Drakulovic MB: Lancet 1999, 354:1851. 1. Drakulovic MB: Lancet 1999, 354:1851. 2. Amato MB: N Engl J Med 1998, 338:347. Introduction Aging causes structural and functional modifications in the respiratory system. The evidence that these changes could impair weaning in elderly patients, until now, was not clear. We designed a protocol to study possible differences between an adult group (AG, up to 60 years) and an elderly group (EG, >60 years) in a daily screening trial. g 3. Cash BD: Crit Care Med 2002, 30:S373. 4. Samama MM: N Engl J Med 1999, 341:793. Application of treatment bundles reduces days on mechanical ventilation in critically ill patients The duration of mechanical ventilation before weaning was 2.5 ± 0.5 days in the SIMV+PSV group vs 2.4 ± 0.4 days in the ITSB group (P = 0.02) and the duration of weaning was 6.2 ± 0.23 hours vs 8.3 ± 0.44 hours in the two groups, respectively (P < 0.01). Patients who remained extubated for 48 hours were classified as having successful extubation – the rate of successful extubation in the first 24 hours of starting weaning was higher for the SIMV group (79.2%) than in the ITSB group (64.7%, P < 0.01). The total duration of mechanical ventilation was 3.3 ± 0.3 days vs 5.2 ± 1.1 days and the ICU length of stay was 5.6 ± 1 days vs 7.5 ± 1.7 days in the two groups, respectively (P < 0.01). Results One hundred and thirty-three patients (1,389 ventilator- days) were included in Audit I, 141 patients (1,002 ventilator-days) in Audit II. Data are expressed as the median (interquartile range) or percentage of implementation per ventilator-days (Table 1). On average, low tidal volume ventilation was adopted. DVTP and SUP were well implemented without training. There was no effect on frequency of pneumonia, ICU length of stay, or survival. Table 1 (abstract P171) Audit I Audit II P APACHE II 24 (10) 25 (11) 0.387 SRP (%) 24.9 49.6 <0.001 TV (ml/kg) 6.3 (2.2) 6.4 (2.3) 0.154 DVTP (%) 89.5 91.9 0.048 SUP (%) 94.5 94.9 0.712 Days on ventilation 6.0 (13) 4.0 (7) 0.017 Conclusions The use of SIMV+PSV as a weaning method in the surgical ICU lead to shorter duration of weaning, a higher rate of successful extubation, a shorter duration of mechanical ventilation and less ICU stay than the use of ITSB. P171 (ITSB) using a T-tube as two methods of weaning in a surgical ICU. Figure 1 (abstract P169) Figure 1 (abstract P169) Figure 1 (abstract P169) Results Sixty patients were studied (52% men, mean age 64 ± 17 years, 18% with chronic obstructive pulmonary disease in threshold group vs 15% in control group). Comparing initial versus final cardiorespiratory variables in both groups, no important differences were observed with exception of PImax (increased from –33.5 ± 14.4 to –40.2 ± 13.4 cmH2O in threshold group and changed from –37.1 ± 9.8 to –34.4 ± 9.6 cmH2O in control group, P < 0.05) and PEmax (increased from 24.7 ± 12.7 to 29.4 ± 12.1 cmH2O in threshold group and changed from 30.9 ± 13.5 to 27.1 ± 9.4 cmH2O in control group, P < 0.05). No reduction was observed in the length of weaning (1.87 days with threshold versus 1.98 days in control group, P > 0.05). There was no difference concerning weaning success (73.5% with threshold versus 61.5% in control group, P > 0.05). Conclusions Threshold during weaning from MV can cause an increase in both PImax and PEmax but, at least in these preliminary results, it was not associated with a decrease in length of weaning or an increase in weaning success. Conclusions Threshold during weaning from MV can cause an increase in both PImax and PEmax but, at least in these preliminary results, it was not associated with a decrease in length of weaning or an increase in weaning success. S69 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin P174 Heart rate variability during weaning from mechanical ventilation A Guntzel, S Vieira, E Ferlim, R Moraes Hospital de Clínicas de Porto Alegre, Brazil Critical Care 2007, 11(Suppl 2):P174 (doi: 10.1186/cc5334) Introduction Acute illness adversely affects a patient’s circadian rhythms. Minimising the delayed restoration of these rhythms may have patient benefits. The aims of this study were to investigate the acute effects of exogenous melatonin on the rest–activity rhythms of patients recovering from critical illness, and furthermore to analyse the rhythms and relationship between plasma melatonin and cortisol levels. Heart rate variability during weaning from mechanical ventilation A Guntzel, S Vieira, E Ferlim, R Moraes Hospital de Clínicas de Porto Alegre, Brazil Critical Care 2007, 11(Suppl 2):P174 (doi: 10.1186/cc5334) Introduction Weaning from mechanical ventilation (MV) can be associated with cardiovascular changes including elevation of heart rate (HR) and development of arrhythmias. The behavior is not yet known of HR variability during weaning from MV comparing pressure support ventilation (PSV) and the T-tube (TT) in patients with and without heart disease. The aim of this study was to evaluate the impact on heart rate variability (HRV) in these groups of patients during PSV and TT. Methods A randomised controlled trial in 24 critically ill patients weaning from mechanical ventilation. Ethics committee approval was granted and all patients provided written consent. Twelve patients in each group received placebo or 10 mg exogenous melatonin at 21:00 hours for four nights. Twelve plasma samples were taken periodically from the first 18 of these patients over a 24-hour period. Actigraphy was used to monitor patient activity. Rhythm analysis of plasma levels and activity data used single cosinor analysis and nonparametric parameters, respectively. Methods Patients with (group 1, n = 8) and without (group 2, n = 22) heart disease, under MV for at least 48 hours, were observed during 30 minutes of PSV or TT, in a random order. Variables analyzed were: APACHE score, length of stay in the ICU (LOS), and cardiorespiratory variables including the HR, respiratory rate (RR), rapid shallow breathing index (f/VT), maximum inspiratory (PImax) and expiratory (PEmax) pressure. Continuous ECG was recorded by the Holter method. The data of HRV were accomplished by analysis of the frequency domain. For statistical analyses, analysis of variance and t test were used. The level of significance was P < 0.05. Results Both groups were well matched. P172 Comparative study of two methods of weaning from mechanical ventilation in a cancer surgical intensive care unit Comparative study of two methods of weaning from mechanical ventilation in a cancer surgical intensive care unit Methods One hundred and forty-four patients (79 EG and 65 AG) were studied. The primary outcome was weaning success (48 hours of spontaneous ventilation after extubation). The secondary outcome was differences in the conventional weaning predictors. Parameters studied included: respiratory rate (f), tidal volume (VT), frequency–tidal volume ratio (f/VT), gasometric and ventilatory parameters. The weaning method was a spontaneous breathing trial. Measurements were performed twice: just before the spontaneous breathing trial (T1) and 30 minutes after (T2). The W Salem1, N Fahmy2 1National Cancer Institute, Cairo, Egypt; 2Faculty of Medicine, Ain Shams University, Cairo, Egypt Critical Care 2007, 11(Suppl 2):P172 (doi: 10.1186/cc5332) W Salem1, N Fahmy2 1National Cancer Institute, Cairo, Egypt; 2Faculty of Medicine, Ain Shams University, Cairo, Egypt Critical Care 2007, 11(Suppl 2):P172 (doi: 10.1186/cc5332) W Salem1, N Fahmy2 1National Cancer Institute, Cairo, Egypt; 2Faculty of Medicine, Ain Shams University, Cairo, Egypt Critical Care 2007, 11(Suppl 2):P172 (doi: 10.1186/cc5332) Introduction The aim of the study was to compare the combination of intermittent mandatory ventilation plus pressure-support ventila- tion (SIMV+PSV) with intermittent trials of spontaneous breathing S70 Available online http://ccforum.com/supplements/11/S2 Table 1 (abstract P173) Weaning criteria T1 AG (n = 65) T2 AG (n = 65) T1 EG (n = 79) T2 EG (n = 79) f (breaths/min) 22 ± 59* 22 ± 5.2* 24 ± 5.5* 24 ± 5.4* VT (ml) 560 ± 200* 550 ± 180* 470 ± 170* 480 ± 150* f/VT 47 ± 24* 46 ± 19* 59 ± 28* 56 ± 24* *P < 0.05 comparing AG and EG. chi-square test, analysis of variance and t test were used in the analysis. Conclusion During weaning from MV, cardiac patients showed higher RR and higher f/VT during TT when compared with PSV. Furthermore, there were significant changes in the RR and HR intervals in TT. However, we did not find significant changes comparing HRV in groups, perhaps because the frequency domain analysis had low power to verify those changes. chi-square test, analysis of variance and t test were used in the analysis. Results Weaning success was 86% both in EG and AG (P = 0.989). There were no differences in gasometric and in ventilatory parameters between groups. Assessment of melatonin, cortisol and rest–activity rhythms in critically ill patients weaning from mechanical ventilation R Bourne Sheffield Teaching Hospitals, Sheffield, UK Critical Care 2007, 11(Suppl 2):P175 (doi: 10.1186/cc5335) P172 Comparisons in TI and T2 in AG and EG are presented in Table 1. Sensitivities of f/VT in T1/T2 were: for EG, 94 (86–98)/96 (89–98); for AG, 95 (86–99)/100 (94.8–100). P175 Conclusion The weaning success in our study is similar to that described in other trials. Older patients showed differences in f, VT and f/VT when compared with adults. However, there were no differences in weaning success. P174 There were no significant differences between the groups in any of the rest–activity measures, which were abnormal and comparable with those previously reported [1]. There was a weak inverse correlation between plasma melatonin and cortisol levels (r = –0.22, P = 0.015). Seven of 18 patients had a circadian rhythm of plasma cortisol levels, while only two patients had a normal acrophase. Four of the nine placebo patients had a circadian rhythm of melatonin, but only one of these had a normal amplitude and acrophase. The plasma melatonin 24-hour area under the curve was significantly reduced compared with healthy elderly people (128.4 (112.6; 217.0) versus 464.5 (372.5; 594.0), P < 0.001). A moderate inverse relationship existed between the percentage plasma cortisol rhythm and patient intradaily variability (r = –0.70, P < 0.002). Results Values for the APACHE score, LOS, PImax and PEmax did not show significant differences comparing groups. The RR was significantly higher during TT than during PSV in group 1 (25 ± 6; 20 ± 4; P < 0.01), but similar in group 2 (22 ± 5; 22 ± 5; not significant (NS)). f/VT was significantly higher during TT in relationship to PSV in group 1 (65 ± 35; 39 ± 17; P < 0.01), but similar in group 2 (49 ± 19; 49 ± 22; NS). Changes in the RR interval comparing PSV and TT were significantly different in the entire group (0.48 ± 55; –30 ± 72; P = 0.02) as well as changes in the HR interval (–0.3 ± 8; 8 ± 12; P < 0.001). Changes in HRV by frequency domain were not significantly different comparing groups 1 and 2 in PSV and TT. The high frequency was in PSV (4 ± 21; 0.4 ± 11; NS), and in TT (–0.64 ± 12; 1 ± 12; NS). The low frequency was in PSV (–11 ± 22; 3 ± 14; NS), and in TT (–6 ± 17; 1.8 ± 19; NS). Conclusions Acute administration of exogenous melatonin did not result in significant differences in rest–activity rhythms between the groups. Most patients lacked circadian rhythms of plasma melatonin and cortisol levels, which were no longer phase locked. The amplitude of plasma melatonin levels are significantly suppressed. 1. Vinzio S, Ruellan A, Perrin AE, et al.: Actigraphic assess- ment of the circadian rest-activity rhythm in elderly patients hospitalized in an acute care unit. Psychiatry Clin Neurosci 2003, 57:53-58. Evaluation of patient parameters that predict success using the SmartCare weaning system P Jackson, G Mills Royal Hallamshire Hospital, Sheffield, UK Critical Care 2007, 11(Suppl 2):P176 (doi: 10.1186/cc5336) P Jackson, G Mills Royal Hallamshire Hospital, Sheffield, UK Critical Care 2007, 11(Suppl 2):P176 (doi: 10.1186/cc5336) Introduction Our aim was to assess the success of the SmartCare (SC) weaning system, to see what associated factors made a successful wean more likely. SC is a knowledge-based weaning system integrated into the Dräger EvitaXL ventilator, designed to optimise the ventilator settings during weaning so that patients can be weaned as quickly as possible. Methods The first 100 consecutive general ICU patients where SC weaning had been attempted were identified. Patient age, sex, APACHE score, diagnosis, worst FiO2 prior to weaning, duration of ventilation prior to weaning, duration of weaning attempt, need for tracheostomy and duration of stay were collected. The patients were then subdivided into unsuccessful and successful weaning attempts based upon whether they required subsequent ventilatory support during the first 48 hours after their weaning ended. The two groups were then analysed to identify the characteristics of the patients where a successful SC wean was achieved. applied to admissions during the 3 years since introduction to estimate the cumulative excess mortality (observed minus expected deaths). Results After excluding patients whose weaning was interrupted by transfer or a decision to withdraw treatment, we had 89 weaning attempts to analyse. These represented 43 successful (S) and 46 unsuccessful (US) weans. Comparison of mean ± SD ages (S 61 ± 14.3 years, US 57.3 ± 16.1 years, P = 0.28) and APACHE scores (S 16.2 ± 4.9, US 17.7 ± 6.5, P = 0.23) for the two groups showed no major differences. Logistic regression demonstrated that the worst FiO2 prior to weaning and the duration of ventilation prior to weaning were both significantly associated with an unsuccessful SC weaning attempt (P = 0.002 and P = 0.005, respectively). ROC curve analysis suggested patients with an FiO2 below 0.47 and a duration of ventilation prior to weaning of below 43 hours were more likely to be successfully weaned. Results There were 762 ventilated admissions prior to the introduction of the bundle and 618 since. The cumulative excess mortality plot suggested a reduction in mortality after introduction of the bundle (Figure 1) but this was not statistically significant (relative risk reduction 10.9%, 95% confidence interval –10.2% to 31.8%). P178 Hemodynamic changes due to expiratory positive airway pressure by facial mask in the postoperative period of cardiac surgery Conclusions SC proved most successful in those patients who had a lower worst FiO2 prior to weaning and a lower duration of ventilation prior to commencing weaning. S Vieira1, A Sena2, S Pinto-Ribeiro1 1Hospital de Clínicas de Porto Alegre, Brazil; 2Santa Casa de Misericórdia de Porto Alegre, Brazil Critical Care 2007, 11(Suppl 2):P178 (doi: 10.1186/cc5338) Evaluation of patient parameters that predict success using the SmartCare weaning system Interpretation The results suggest that it will be beneficial to carry out a multicentre evaluation of the ventilator bundle in Case Mix Programme units, and will inform the design of this study. Reference 1. Vinzio S, Ruellan A, Perrin AE, et al.: Actigraphic assess- ment of the circadian rest-activity rhythm in elderly patients hospitalized in an acute care unit. Psychiatry Clin Neurosci 2003, 57:53-58. 1. Vinzio S, Ruellan A, Perrin AE, et al.: Actigraphic assess- ment of the circadian rest-activity rhythm in elderly patients hospitalized in an acute care unit. Psychiatry Clin Neurosci 2003, 57:53-58. S71 Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine Figure 1 (abstract P177) Figure 1 (abstract P177) Figure 1 (abstract P177) P179 Methods We conducted a retrospective audit of consecutive patients receiving APRV from January 2004 to August 2006 in three academic ICUs in Toronto. APRV was initiated at the discretion of the attending physician; a protocol guiding the implementation of APRV was introduced in July 2006. We recorded data describing: baseline characteristics; how APRV was used; its potential ramifications including oxygenation and sedation/analgesia doses; and outcomes. Predicting successful nasal continuous positive airway pressure treatment in newborn infants: a multivariate analysis J Swietlinski1, T Bachman2, K Bober3, E Gajewska4, E Helwich5, R Lauterbach6, M Manowska1, B Maruszewski1, J Szczapa7, L Hubicki3, on behalf of the Polish Study Group (NRSP) 1The Children’s Memorial Health Institute, Warsaw, Poland; 2California State University, San Bernardino, CA, USA; 3Medical University of Silesia, Katowice, Poland; 4Medical University, Wrocùaw, Poland; 5National Research Institute of Mother & Child, Warsaw, Poland; 6Medical College Jagiellonian University, Kraków, Poland; 7University of Medical Sciences, Poznan, Poland Critical Care 2007, 11(Suppl 2):P179 (doi: 10.1186/cc5339) J Swietlinski1, T Bachman2, K Bober3, E Gajewska4, E Helwich5, R Lauterbach6, M Manowska1, B Maruszewski1, J Szczapa7, L Hubicki3, on behalf of the Polish Study Group (NRSP) J Swietlinski1, T Bachman2, K Bober3, E Gajewska4, E Helwich5, R Lauterbach6, M Manowska1, B Maruszewski1, J Szczapa7, L Hubicki3, on behalf of the Polish Study Group (NRSP) g ; Results Thirty patients, all with ALI/ARDS, received 39 trials of APRV during the study period – median age 52 years, 60% male, 50% pulmonary ALI risk factor, median APACHE II score 28. They had ALI for a median of 4.5 days with a median 135 hours of CMV before APRV. They received a median of 38 hours APRV. By 12 hours, oxygenation improved significantly (P/F ratio from 103 to 159, P < 0.01), with a concomitant decrease in FiO2 requirements (from 0.70 to 0.50, P < 0.0006). At 72 hours, the median P/F ratio had improved to 196 on a median FiO2 of 0.40 (both P < 0.01). Administration and dosages of sedatives (midazolam equivalents, propofol) and analgesics (morphine equivalents) did not change significantly over the period from 24 hours before to 24 hours after APRV initiation. There were two episodes of barotrauma during APRV; neither required therapeutic drainage. The 30-day mortality was 13/30 (43%), most commonly due to multiorgan failure and withdrawal of life-support. Assessing the impact of introducing the ‘ventilator bundle’ on outcomes for mechanically ventilated patients Comparing rest and EPAP periods, increases were observed in: PCWP (11.9 ± 3.8 to 17.1 ± 4.9 mmHg, P < 0.001); CVP (8.7 ± 4.1 to 10.9 ± 4.3 mmHg, P = 0.014); MPAP (21.5 ± 4.2 to 26.5 ± 5.8 mmHg, P < 0.001); MAP (76 ± 10 to 80 ± 10 mmHg, P < 0.035). All other variables did not show significant changes. These results were observed in the total group and when divided concerning ejection fraction >50% or <50%. Conclusions EPAP was well tolerated in this group of stable patients after cardiac surgery and the hemodynamic changes due to its use were an increase in the measurement of right and left filling pressures as well as a small increase in arterial pressure. Assessing the impact of introducing the ‘ventilator bundle’ on outcomes for mechanically ventilated patients Assessing the impact of introducing the ‘ventilator bundle’ on outcomes for mechanically ventilated patients Introduction Expiratory positive airway pressure (EPAP) is used as physiotherapic tool in the management of patients after major surgeries such as cardiac surgery but its hemodynamic effect is not well studied. The goal of this study was to evaluate hemodynamic changes caused by EPAP use after cardiac surgery in patients monitored by Swan-Ganz catheter. D Harrison, K Rowan Intensive Care National Audit & Research Centre, London, UK Critical Care 2007, 11(Suppl 2):P177 (doi: 10.1186/cc5337) Background The concept of bundles was developed by the Institute for Healthcare Improvement. Individual bundle elements are built on evidence-based practice, and the bundle concept is that when these elements are executed together they produce better outcomes than in isolation. There is, however, limited evidence linking the use of bundles to demonstrable changes in patient outcomes. As a preliminary analysis to inform a multicentre evaluation, we explored the effect of the introduction of the ‘ventilator bundle’ on the outcomes for mechanically ventilated patients in a single critical care unit. Methods Patients in the first or second day after cardiac surgery, with respiratory and hemodynamic stability and with a Swan-Ganz catheter, were included. They were evaluated at rest and after using EPAP of 10 cm, by facial mask, in a randomized order. Variables studied were oxygen saturation (SPO2), heart rate (HR), respiratory rate (RR), mean arterial systemic and pulmonary pressures (MAP and MPAP), central venous pressure (CVP), pulmonary capillary wedge pressure (PCWP), cardiac index, stroke index, stroke work index from left and right ventricles, and systemic and pulmonary vascular resistance. Patients were studied as a whole group and divided into subgroups (with ejection fraction <50% or >50%) and values were compared with a t test and analysis of variance. Results are shown as the mean ± standard deviation. The significance level was P < 0.05. Methods Data were extracted for mechanically ventilated admissions from a single unit participating in the Case Mix Programme that was an early adopter of the ventilator bundle. A risk prediction model was developed using data from admissions during the 3.5 years prior to the introduction of the bundle and S72 Available online http://ccforum.com/supplements/11/S2 Results Twenty-eight patients were studied (22 men, mean age 68 ± 11 years). The most common surgery was myocardial revascularization (n = 17). EPAP was well tolerated in the patients studied. P179 1The Children’s Memorial Health Institute, Warsaw, Poland; 2California State University, San Bernardino, CA, USA; 3Medical University of Silesia, Katowice, Poland; 4Medical University, Wrocùaw, Poland; 5National Research Institute of Mother & Child, Warsaw, Poland; 6Medical College Jagiellonian University, Kraków, Poland; 7University of Medical Sciences, Poznan, Poland Critical Care 2007, 11(Suppl 2):P179 (doi: 10.1186/cc5339) Background The use of nasal continuous positive airway pressure (nCPAP) in newborn infants is common, especially for weaning after mechanical ventilation. We have reported on the successful transition to the use of the infant flow method as a standard of practice in Poland. Objective The authors present results of multivariate logistic regression (MLR) analysis of 481 newborns treated with the infant flow method in an effort to improve related clinical guidance. Conclusions In our patients APRV use appeared safe, led to improved oxygenation, but did not change needs for sedation/analgesia. Future studies are needed to determine the optimal timing and methods for ARPV use; these should be followed by randomized trials to confirm safety and document the effects of APRV on patient-centered outcomes. Methods We collected data on the baseline demographic, physiological characteristics and outcomes of 1,299 newborns treated with nCPAP in 57 neonatal ICUs in Poland over a 2-year period. We conducted a stepwise MLR of 481 newborns with the two most common indications for use. We evaluated three outcomes: need for intubation in newborns treated electively with nCPAP (RDS), weaning failure requiring reintubation in the mechanically ventilated newborns (weaning), and bad outcome. Airway pressure release ventilation in acute lung injury/acute respiratory distress syndrome patients E Fan1, A Mullaly1, M Ko1, J Lyle1, T Pirano1, C Harris1, J Traill1, J Rosenberg1, J Granton1, T Stewart2, N Ferguson1 1University of Toronto, Canada; 2Mount Sinai Hospital, Toronto, Canada Critical Care 2007, 11(Suppl 2):P180 (doi: 10.1186/cc5340) Introduction Advocates of airway pressure release ventilation (APRV) suggest that this mode is lung-protective for patients with ALI/ARDS, while providing additional benefits of spontaneous breathing, including improved haemodynamics, decreased need for sedation, and better patient comfort. However, there are few available data on the clinical experience with APRV. P181 A compliance-based index (CSI) directly comparable with the SI was generated from the compliance data. convertase are scarce. We therefore investigated the expression and activity of lung surfactant convertase and HMSE-1, a potential macrophage-derived human convertase, under normal and acute inflammatory conditions. Methods Convertase activity in lavage fluid (BALF) was assessed using the in vitro cycling assay. The relative large surfactant aggregate content was determined by phospholipid quantification in the pellet following centrifugation at 48,000 x g. Esterase activity was assessed by means of a chromogenic substrate assay. Expression of both convertase and HMSE upon LPS challenge was assessed by real-time (TaqMan) PCR in murine alveolar macrophages, murine primary type II cells, and the human monocytic cell line U937, respectively. Results The SI and CSI highly correlated when calculation of the CSI was based on the same database (Figure 1). According to the resulting regression formula (Figure 1), the SI can be reliably predicted from SLICE_SI (Figure 2). However, if SLICE_CONV was used for calculation of the SI (Figure 3), noticeable differences were found. Analysis of individual datasets showed three major reasons for the observed differences: differences in excluded data at low volumes respective to high volumes, nonlinearity of resistance, and differences in mechanics between inspiration and expiration. Results Lavage fluid from ARDS patients displayed an increased esterase activity when compared with BALF from healthy controls. In addition, a pronounced large to small aggregate conversion was observed for BALF from LPS-challenged mice or BALF from ARDS patients. Incubation with LPS resulted in a significant increase in convertase gene expression in primary mouse type II cells as well as in HMSE-1 gene expression in U937 cells and monocytes from peripheral blood. No convertase expression was found in cultured murine alveolar macrophages. Conclusion The SI and SLICE similarly measure the nonlinearity of compliance. The SI can be predicted from SLICE. However, nonlinearities of the respiratory system are not restricted to compliance alone; it might therefore be necessary to include nonlinearities of resistance and asymmetries between inspiration and expiration in the analysis of dynamic respiratory mechanics. Conclusions An increased convertase activity was found under acute inflammatory conditions of the alveolar compartment, and type II cells seem to be a relevant source of this increased convertase activity. However, leakage of esterase activity from the vascular space and other inflammatory cells cannot be ruled out. 1. P183 Transgenic mice expressing a surfactant protein B–urokinase fusion protein in the distal respiratory epithelium are protected against acute lung injury and postinflammatory fibrosis 3. Guttmann J, et al.: Determination of volume-dependent res- piratory system mechanics in mechanically ventilated patients using the new SLICE method. Technol Health Care 1994, 2:175-191. 3. Guttmann J, et al.: Determination of volume-dependent res- piratory system mechanics in mechanically ventilated patients using the new SLICE method. Technol Health Care 1994, 2:175-191. P Markart1, C Ruppert1, M Wygrecka1, K Petri1, V Magdolen2, T Weaver3, W Seeger1, A Günther1 1University of Giessen Lung Center, Giessen, Germany; 2Klinikum rechts der Isar, Technical University of Munich, Germany; 3Children’s Hospital Medical Center, Cincinnati, OH, USA Critical Care 2007, 11(Suppl 2):P183 (doi: 10.1186/cc5343) P181 Stahl CA, et al.: Dynamic versus static respiratory mechan- ics in acute lung injury and acute respiratory distress syn- drome. Crit Care Med 2006, 34:2090-2098. 2. Ranieri VM, et al.: Pressure–time curve predicts minimally injurious ventilatory strategy in an isolated rat lung model. Anesthesiology 2000, 93:1320-1328. 2. Ranieri VM, et al.: Pressure–time curve predicts minimally injurious ventilatory strategy in an isolated rat lung model. Anesthesiology 2000, 93:1320-1328. P181 Results In the RDS group of patients we found that nCPAP failure was highly significantly related to estimated gestational age and clinical risk index for babies (CRIB). While in our population less mature RDS newborns were only slightly less likely to avoid intubation, the MLR model showed that, controlling for initial CRIB, they were less than one-half as likely to avoid intubation. Failure of nCPAP in weaning was highly significantly related to only pH, prior to beginning nCPAP. Bad outcomes were highly related to estimated gestational age and CRIB in the RDS group, but not the weaning population. Importance of nonlinearities to quantify mechanical pulmonary stress under dynamic conditions: stress index and SLICE method C Stahl1, H Meißner1, D Steinmann1, G Mols1, C Micelli2, K Moeller3, M Ranieri4, J Guttmann1 1Anästhesiologische Universitätsklinik, Freiburg, Germany; 2Kleistek, Bari, Italy; 3HFU, Villingen-Schwenningen, Germany; 4Oespedale S. Giovanni Battista, Torino, Italy Critical Care 2007, 11(Suppl 2):P181 (doi: 10.1186/cc5341) Conclusions We believe that understanding the risk of both nCPAP failure and also bad outcomes for a specific patient will enhance clinical decision-making. That is, for patients with the highest risk of poor outcome or nCPAP failure, more aggressive use of intubation and surfactant might be warranted. Likewise, such aggressive therapy might also be avoided for those with a seemingly low chance of poor outcome. Introduction Recent data suggest that dynamic measurements of respiratory mechanics should be preferred to static measurement for lung protection [1]. The aim of this study was to analyze similarities and differences between dynamic methods: the stress index (SI) [2] and SLICE [3]. S73 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine Figures 1-3 (abstract P181) Figures 1-3 (abstract P181) Figures 1-3 (abstract P181) Methods One hundred and two respiratory datasets from 70 patients (28 ARDS, 24 postanesthesia care, 18 other) were analyzed. The SI and SLICE were performed using exactly the same database (SLICE_SI) in addition to the conventional SLICE that includes inspiratory and expiratory data (SLICE_CONV). A compliance-based index (CSI) directly comparable with the SI was generated from the compliance data. Methods One hundred and two respiratory datasets from 70 patients (28 ARDS, 24 postanesthesia care, 18 other) were analyzed. The SI and SLICE were performed using exactly the same database (SLICE_SI) in addition to the conventional SLICE that includes inspiratory and expiratory data (SLICE_CONV). P184 Mini-bronchoalveolar lavage with and without surfactant in the treatment of recurrent atelectasis in pediatric intensive care patients M Karaman Iliã, I Škariã, I Kerovec Children’s Hospital, Zagreb, Croatia Critical Care 2007, 11(Suppl 2):P184 (doi: 10.1186/cc5344) M Karaman Iliã, I Škariã, I Kerovec Children’s Hospital, Zagreb, Croatia Critical Care 2007, 11(Suppl 2):P184 (doi: 10.1186/cc5344) Introduction Since traditional treatment of atelectasis is often insufficient to reopen the collapsed airways, mini-bronchoalveolar lavage (mini-BAL) is performed. We retrospectively compared the treatment effects of mini-BAL only and mini-BAL combined with surfactant in the treatment of pediatric ICU patients with recurrent atelectasis. Methods A retrospective analysis included a heterogeneous group of 18 mechanically ventilated pediatric ICU patients with recurrent atelectasis. Nine patients (mean age, 4.4 ± 3.4 years) who received surfactant after standard mini-BAL were compared with nine patients (mean age, 4.7 ± 3.0 years) who underwent only standard mini-BAL. Gas exchange and pulmonary mechanic parameters in the two groups were compared. The peak inspiratory pressure (PIP), positive end-expiratory pressure (PEEP), paO2/FiO2, and partial arterial carbon dioxide pressure (paCO2) were analyzed with 3 x 2 multivariate analysis of variance, with the time of measurement (before treatment, 6 and 12 hours after treatment) as a within- subject factor and the type of treatment (mini-BAL only vs mini-BAL with surfactant) as a between-subject factor. Results The computer-driven ventilator settings could stabilise the ventilation of the lung-injured subject in the predefined thresholds. Compared with the beginning of the study, a reduction in ventilation pressure and PaCO2 could be observed. Despite the initial low PaO2/FiO2 ratio (<200 mmHg) of the subjects, FiO2 could be decreased by the system in the given time without penetrating the thresholds for oxygenation. Results The groups did not differ in age (independent sample t test = 0.698). The parameters significantly changed with time after treatment (Wilks’ λ = 0.027, F = 25.277, P < 0.001), and the treatment procedures had significantly different effects (time x treatment, Wilks’ λ = 0.103, F = 6.070, P = 0.013). A significant univariate time–treatment interaction was not present only for SpO2 (F(2,32) = 2.167, P = 0.629). Subsequent analyses showed different effect of surfactant administration on PEEP compared with mini-BAL alone. In the mini-BAL only group, PEEP changed from 6.44 ± 1.13 cmH2O before treatment to 5.22 ± 0.83 cmH2O 6 hours after the treatment (P = 0.019), and remained the same 12 hours after the treatment. P182 Contribution of HMSE-1 to surfactant conversion under acute inflammatory conditions Contribution of HMSE-1 to surfactant conversion under acute inflammatory conditions Contribution of HMSE-1 to surfactant conversion under acute inflammatory conditions C Ruppert, P Markart, S Händel, W Seeger, A Günther University of Giessen Lung Center, Giessen, Germany Critical Care 2007, 11(Suppl 2):P182 (doi: 10.1186/cc5342) C Ruppert, P Markart, S Händel, W Seeger, A Günther University of Giessen Lung Center, Giessen, Germany Critical Care 2007, 11(Suppl 2):P182 (doi: 10.1186/cc5342) C Ruppert, P Markart, S Händel, W Seeger, A Günther University of Giessen Lung Center, Giessen, Germany Critical Care 2007, 11(Suppl 2):P182 (doi: 10.1186/cc5342) Introduction Persistent deposition of fibrin in the distal lung is thought to play a significant role in the pathogenesis of acute lung injury (ALI) and postinflammatory lung fibrosis. The therapeutic concept of the correction of the alveolar hemostatic balance, although effective in most models, needs further improvement in view of specific targeting of surfactant-containing alveolar fibrin clots. Introduction A reduced content of biophysically active large surfactant aggregates is a common finding in acute inflammatory lung disease. Cyclic surface area changes and a carboxylesterase activity (surfactant convertase) are thought to mediate this subtype conversion. However, data concerning regulation of surfactant Introduction A reduced content of biophysically active large surfactant aggregates is a common finding in acute inflammatory lung disease. Cyclic surface area changes and a carboxylesterase activity (surfactant convertase) are thought to mediate this subtype conversion. However, data concerning regulation of surfactant S74 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Methods In the present study we generated transgenic mice that express a surfactant protein B–urokinase fusion protein (SPUC) in the distal respiratory epithelium under the control of the 3.7 kb human SP-C promotor. Survival was determined in a lethal ALI model (inhalative LPS administration) in SPUC mice compared with wild-type mice of the same genetic background. Furthermore, the outcome, lung function, collagen content and histology were assessed in the model of bleomycin-induced pulmonary fibrosis. had significantly lower PEEP values compared with the mini-BAL only group 12 hours after the treatment (3.44 ± 0.72 before vs 5.22 ± 0.44 mmH2O after treatment, P = 0.025). had significantly lower PEEP values compared with the mini-BAL only group 12 hours after the treatment (3.44 ± 0.72 before vs 5.22 ± 0.44 mmH2O after treatment, P = 0.025). 2 Conclusion Mini-BAL is efficient in the treatment of recurrent atelectasis in pediatric ICU patients. P184 The group that received surfactant Conclusion Robust execution of an automated ARDS Network protocol with an electronically controlled ventilator is possible and leads to pulmonary stabilisation. Further trials have to be undertaken before this successful approach can be realised in ARDS patients. P182 Beneficial effects of surfactant administration after mini-BAL should be confirmed prospectively in a larger number of patients. Results Transgenic mice showed an improved survival after inhalative LPS or bleomycin administration as compared with wild- type mice. The fibrotic response to inhalative bleomycin challenge was markedly attenuated in transgenic mice, as evident by reduced histological appearance of fibrosis, improved pulmonary compliance and reduced lung hydroxyproline content. As potential underlying mechanisms for the attenuated fibrotic response we observed an improvement in alveolar surface activity, a decrease in pulmonary fibrin deposition, increased hepatocyte growth factor levels and decreased gelatinase activity in the BAL fluids of transgenic mice as compared with control animals. Automated mechanical ventilation based on the ARDS Network protocol in porcine acute lung injury Automated mechanical ventilation based on the ARDS Network protocol in porcine acute lung injury T Meier1, H Luepschen2, M Großherr1, J Karsten1, S Leonhardt2 1Medical University of Schleswig Holstein, Campus Lübeck, Germany; 2Medical Information Technology, RWTH Aachen, Germany Critical Care 2007, 11(Suppl 2):P185 (doi: 10.1186/cc5345) Introduction The results of the ARDS Network trial [1] demon- strated a significant reduction of mortality by using a mechanical ventilation protocol with tidal volumes (VT) of 6 ml/kg predicated body weight. Additionally, a computer-driven weaning protocol was successfully performed and a reduction of mechanical ventilation duration could be demonstrated [2]. The implementation of the ARDS Network protocol in routine ICU practice remains modest [3]. A possible reason is the increased organisational and temporal burden. An automated execution of the protocol would help to propagate its day-to-day use. To test the ability to automate such a complex protocol, we designed a pilot study in porcine acute lung injury using an experimental medical expert system capable of continuously controlling respiratory parameters and global as well as regional ventilation with electrical impedance tomography (EIT). Methods After induction of saline lavage-induced lung injury in pigs (n = 3), automated mechanical ventilation was initiated. The medical expert system used a closed-loop fuzzy controller with a rule base of if/then rules based on the ARDS Network protocol reference card. The protocol’s algorithmic rules and therapeutic goals (oxygenation, pH, I:E, VT) were continuously controlled and ventilatory settings electronically adjusted accordingly. The medical attendant personnel was constantly informed with status messages about the decisions made. During the trial, all measurements were made using an online blood gas monitor (TrendCare Satellite; Diametrics Medical Inc., UK), a monitor for hemodynamic parameters (Sirecust 1281; Siemens, Germany), a capnograph (CO2SMO+; Respironics, Inc., USA), and an EIT prototype system (EIT Evaluation Kit; Draeger Medical, Germany). Subjects were ventilated for between 40 and 90 minutes. Conclusions Lung-specific expression of a surfactant protein B–urokinase fusion protein protects against ALI after inhalative LPS challenge and prevents fibrosis associated with bleomycin- induced lung injury. P185 Automated mechanical ventilation based on the ARDS Network protocol in porcine acute lung injury T Meier1, H Luepschen2, M Großherr1, J Karsten1, S Leonhardt2 1Medical University of Schleswig Holstein, Campus Lübeck, Germany; 2Medical Information Technology, RWTH Aachen, Germany Critical Care 2007, 11(Suppl 2):P185 (doi: 10.1186/cc5345) P188 Maximal recruitment strategy guided by thoracic CT scan in severe acute respiratory distress syndrome patients: a case series report Methods A systematic literature search was performed between 1966 and July 2006 to identify randomised controlled trials evaluating prone ventilation. G De Matos1, J Borges2, E Meyer1, C Hoelz1, R Passos1, M Rodrigues1, C Carvalho2, M Amato2, C Barbas1 1Hospital Israelita Albert Einstein, São Paulo, Brazil; 2Hospital das Clínicas Faculdade de Medicina Universidade de São Paulo, Brazil Critical Care 2007, 11(Suppl 2):P188 (doi: 10.1186/cc5348) Measurements and results Of 229 studies evaluating prone ventilation, five were suitable for inclusion. Prone ventilation was not associated with a reduction in mortality (OR = 0.99; 95% CI = 0.74–1.30), but improvement in oxygenation was significant (mean difference 21.2; P < 0.001). There was no significant difference in the incidence of pneumonia, ICU stay and endotracheal tube complications. There was a trend towards an increased incidence of pressure sores in prone-ventilated patients. The data on duration of mechanical ventilation, intravascular catheter complications or hospital stay were not suitable for meta-analysis. No study reported cost-effectiveness. Introduction There is great controversy concerning protective ventilation in ARDS. Recruitment maneuvers and PEEP titration sufficient to avoid collapse and tidal recruitment are the major goals of the maximal recruitment strategy (MRS). Objectives To describe clinical and demographic data. To evaluate the incidence of complications related to transportation and to the MRS. Conclusions The use of prone ventilation is associated with improved oxygenation. It is not associated with a reduction in mortality, pneumonia or ICU stay and may be associated with an increased incidence of pressure sores. Methods Forty-three patients with ARDS were transported to CT and submitted to the MRS, which consisted of 2-minute steps of ventilation with a fixed PCV = 15 cmH2O and progressive PEEP levels (10–45–25–10 cmH2O), RR = 10, I:E = 1:1, and FiO2 = 1.0. Opening (recruitment) and closing (PEEP titration) pressures were determined according to the least amount of collapse observed at the CT, and were used to ventilate the patients afterwards. Efficacy of prone ventilation in adult patients with acute respiratory failure: a meta-analysis Efficacy of prone ventilation in adult patients with acute respiratory failure: a meta-analysis R Tiruvoipati1, M Bangash1, B Manktelow2, G Peek1 1Glenfield Hospital, Leicester, UK; 2University of Leicester, UK Critical Care 2007, 11(Suppl 2):P186 (doi: 10.1186/cc5346) Background The use of prone ventilation in acute respiratory failure has been investigated by several randomised controlled trials in the recent past. To date there has been no systematic review or meta-analysis of these trials. Conclusions PPV had a positive effect on gas exchange even after 6 hours. This effect lasts through the PPV period. Because of its effect on the LIS, a duration of 24 hours for continuous PPV could be useful in this patient setting. Objectives The primary objective was to assess the efficacy of prone ventilation in reducing mortality of adult patients with acute respiratory failure. The secondary objective was to evaluate changes in oxygenation, incidence of pneumonia, duration of mechanical ventilation, ICU and hospital stay, and adverse effects including pressure sores, endotracheal tube or intravascular catheter complications and cost-effectiveness of using prone ventilation. P186 before PPV and 256 (170–298) mmHg after 1 hour of PPV (P = 0.001). This difference with the supine PaO2/FIO2 ratio was sustained until the end of PPV. Initial values of PEEP were set at 15 (12–18) cmH2O by constructing a PEEP-compliance curve; there were no differences in PEEP values along the study. Initial values of PaCO2 were 47 (41–69) mmHg and there were no significant differences along the study period. After 24 hours of PPV, the LIS was significantly decreased in comparison with the supine value before PPV: 3 (2.25–2.7) vs 2.5 (2.25–2.75), P = 0.001. There were no significant complications. P186 Efficacy of prone ventilation in adult patients with acute respiratory failure: a meta-analysis R Tiruvoipati1, M Bangash1, B Manktelow2, G Peek1 1Glenfield Hospital, Leicester, UK; 2University of Leicester, UK Critical Care 2007, 11(Suppl 2):P186 (doi: 10.1186/cc5346) References References 1. ARDS Network: N Engl J Med 2000, 342:1301-1308. 2. Lellouche et al.: Am J Respir Crit Care Med 2006, 174:894- 900. S75 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin P186 Continuous long-term prone position ventilation effects in pulmonary acute respiratory distress syndrome patients Results Clinical data are presented in Table 1. There were no complications due to transportation and one patient developed pneumomediatinum after the protocol. J Gorrasi, F Pracca, A Iturralde, L Moraes, D Fischer, M Cancela Department of Intensive Care Medicine, University Hospital, School of Medicine, Montevideo, Uruguay Critical Care 2007, 11(Suppl 2):P187 (doi: 10.1186/cc5347) P189 Low sensitivity of measurements of respiratory mechanics in detecting lung edema from high tidal volume mechanical ventilation Low sensitivity of measurements of respiratory mechanics in detecting lung edema from high tidal volume mechanical ventilation Introduction High tidal volume mechanical ventilation (HTVMV) leads to pulmonary edema from increased endothelial permeability. The lungs show evidence of inflammation with endothelial adhesion molecule expression, infiltrates of white blood cells and cytokine production. In order to understand the molecular mechanisms responsible for the pathogenesis of ventilator injury, mouse models are beneficial but technically difficult due to the small size of the animal. To study the time course of lung edema formation we compared lung elastance measured by forced oscillations with invasive methods of lung edema detection (for example, wet–dry weight ratio and histology). Introduction High tidal volume mechanical ventilation (HTVMV) leads to pulmonary edema from increased endothelial permeability. The lungs show evidence of inflammation with endothelial adhesion molecule expression, infiltrates of white blood cells and cytokine production. In order to understand the molecular mechanisms responsible for the pathogenesis of ventilator injury, mouse models are beneficial but technically difficult due to the small size of the animal. To study the time course of lung edema formation we compared lung elastance measured by forced oscillations with invasive methods of lung edema detection (for example, wet–dry weight ratio and histology). Figure 2 (abstract P190) Figure 2 (abstract P190) p y g gy Methods C57Black6 mice were anesthetized with i.p. sodium pentothal and paralyzed with succinylcholine. A tracheostomy was performed and the animals were connected to a Flexivent ventilator (Sqirec). The HTVMV group received a tidal volume of 25 ml/kg and 33 breaths/minute for 4 hours. The control group received 7 ml/kg at 120 breaths/minute. Temperature was kept at 36–37°C with the aid of a heated pad. The heart rate was monitored with surface EKG electrodes. Lung elastance and tissue energy dissipation were measured every 30 minutes using the forced oscillation technique. At the end of the experiment a sternotomy was performed. A ligature was placed around the right hilum and the right lung was cut, briefly rinsed in PBS, blotted dry and weighed. The dry weight was obtained following desiccation at 60°C for 48 hours. The left lung was inflated with 500 µl formalin injected slowly into the tracheal canula and embedded in paraffin. Table 1 (abstract P188) Table 1 (abstract P188) Mortality (%) 28 Age (years) 49 ± 17 APACHE II score 20 ± 6 SOFA D1 score 9.4 ± 3 SOFA D7 score 5.2 ± 4 Maximal recruitment pressure (cmH2O) 60 ± 5 Maximal PEEP day 1 (cmH2O) 25 ± 3 Maximal plateau pressure day 1 (cmH2O) 40 ± 5 PaO2/FiO2 ratio before recruitment protocol 130 ± 43 PaO2/FiO2 ratio after recruitment protocol 317 ± 99 Introduction The optimal duration of prone position ventilation (PPV) in acute respiratory distress syndrome (ARDS) is uncertain. It has been pointed out that pulmonary ARDS patients respond less than extrapulmonary ARDS patients. Objective To study effects of continuous long-term PPV on gas exchange, PEEP, lung injury score and multiorgan failure in pulmonary ARDS patients. Materials and methods The design was a prospective (cohort). We studied 42 PPV periods in 33 pulmonary ARDS patients. Measures were taken in the supine position before PPV and at 1 hour after PPV, and then every 6 hours until the end of PPV. Statistical values are expressed as the median and interquartile range. Wilcoxon and Kruskal–Wallis tests were used. P < 0.05 was considered significant. Conclusions MRS was well tolerated in this series of patients, rendered the gas distribution through the lung more homogeneous, improved gas exchange and was related to low mortality. A RCT to test the MRS is necessary. Results The mean age was 44 (25–57) years, the initial lung injury score (LIS) was 3.1 (2.75–3.6), and PPV was maintained for 91 (51–117) hours. The PaO2/FIO2 ratio was 125 (99–181) mmHg S76 Available online http://ccforum.com/supplements/11/S2 Figure 1 (abstract P190) Figure 2 (abstract P190) Figure 1 (abstract P190) Figure 1 (abstract P190) P189 Paraffin blocks were sectioned with a microtome at 5 µm thickness and stained with hematoxylin–eosin. established. The pressure dependency (or volume dependency respectively) of respiratory resistance of these patients is mostly ignored. This study was performed to investigate the pressure dependency of resistance in ALI and ARDS over a wide range of pressures. Results The wet-to-dry weight ratios rose from 4.82 ± 0.16 in control animals to 6.34 ± 0.83 in the HTVMV group (P < 0.05, n = 4). Light microscopic examination of histologic sections showed mononuclear white cell infiltrates around small arteries and within the alveolar walls of mice in the HTVMV group but not in control mice. Elastance rose nonsignificantly during the HTVMV protocol. Methods Twenty-one patients with ALI or ARDS were analyzed. Ventilation was interrupted by a respiratory manoeuvre: the volume was increased from ZEEP in steps of 100 ml with constant inspiratory flow until the plateau pressure reached 45 cmH2O. Each step was followed by a hold of 3 seconds. Inspiratory resistance during each step was determined by a least-squares fitting procedure. Conclusions In this in vivo mouse model, high tidal volume mechanical ventilation caused pulmonary edema and lung tissue infiltration with white blood cells. However, measurements of lung mechanics showed minimal changes during the course of the experiment, indicating that they are less useful in detecting early edema. Results Resistance decreased from 10.7 ± 5.1 cmH2O·s/l at 5 cmH2O to 8.1 ± 4.0 cmH2O·s/l at 40 cmH2O (P < 0.05). Figure 1 shows individual absolute values and means ± SD of all patients. Most of the decrease was found up to 20 cmH2O; at higher pressures, changes were not uniform. The average relative changes in inspiratory resistance (±SD) of all patients are shown in Figure 2. Alveolar microscopy: on the automatic determination of alveolar size during ventilation J Karsten1, H Luepschen2, M Grossherr1, H Gehring1, S Leonhardt2, T Meier1 1University of Lübeck, Germany; 2Medical Information Technology, Helmholtz Institute, RWTH Aachen, Germany Critical Care 2007, 11(Suppl 2):P192 (doi: 10.1186/cc5352) D Schwenninger1, K Moeller1, C Stahl2, S Schumann2, J Guttmann2 1Furtwangen University, Villingen-Schwenningen, Germany; 2University of Freiburg, Germany Critical Care 2007, 11(Suppl 2):P191 (doi: 10.1186/cc5351) Introduction Alveolar recruitment and maintenance of lung volume are important goals in the treatment of acute lung injury (ALI) and essential for improving oxygenation. The most usual employed strategy to achieve this goal is the use of positive end-expiratory pressure (PEEP). Recruitment and collapse are highly dynamic phenomena that are difficult to monitor. Dynamic effects of regional ventilation can be monitored by electrical impedance tomography (EIT) at the bedside [1]. We investigated the ability of EIT for providing a useful tool to detect dynamic changes of regional breath by breath recruitment at the bedside during an incremental and decremental PEEP trial in experimental lung injury. In addition, we analyzed pressure–volume (P–V) curves computed by EIT data. Methods ALI was induced in six pigs by repetitive lung lavage. After stabilization of the lung injury model (> 1 hour) a stepwise PEEP trial was performed consisting of 2-minute steps of tidal ventilation (10–30 cmH2O; 30–5 cmH2O). During the PEEP trial subjects were ventilated pressure-controlled. Global ventilatory and gas exchange parameters were continuously recorded. Offline we analysed EIT data by computing the amount of breath by breath recruitment (∆V EIT) at each pressure level before and after lung lavage. Nondependent and dependent regions of interest were defined in the tomograms. ∆V EIT was defined as the mean increase or decrease in end-expiratory global impedance per breath. Introduction Alveolar microscopy seems to provide important insight into alveolar dynamics during mechanical ventilation [1,2]. The utility of this method is limited due to high efforts needed to evaluate sequences of images with respect to alveolar geometry. The evaluation – done by hand – is time consuming, places a high cognitive load on the examiner and is error prone. Reproducibility of results is low. This project aims to establish a computer-assisted tool that provides semi-automatic evaluation of video sequences acquired with alveolar endoscopy. Methods We developed a computer program based on Matlab (Mathworks, Natick, MA, USA), which analyses video sequences acquired with an alveolar endoscope (Schölly, Denzlingen, Germany) [2]. Reference 1. Victorino et al.: Am J Respir Crit Care Med 2004, 169:791- 800. frames allows one to compensate for motion artifacts and to analyze the intratidal changes in alveolar geometry. P193 Conclusion Given a synchronization with respiratory data, this tool will allow one to quantify pressure-related changes of alveolar size. Thus it will allow one to monitor the alveolar distension in a variety of animal models (for example, lavage-induced ARDS) and to correlate these findings, for example, with outcome. Pressure dependency of respiratory resistance in patients with acute lung injury and acute respiratory distress syndrome Conclusion Inspiratory resistance in ALI and ARDS is not constant. Especially at higher pressures, individual resistance may change unpredictably. The assumption of a constant resistance should therefore be avoided. C Stahl1, H Knorpp1, S Schumann1, D Steinmann1, K Möller1, J Guttmann1 1Anästhesiologische Universitätsklinik, Freiburg, Germany; 2Biomedical Engineering, HFU, Villingen-Schwenningen, Germany Critical Care 2007, 11(Suppl 2):P190 (doi: 10.1186/cc5350) C Stahl1, H Knorpp1, S Schumann1, D Steinmann1, K Möller1, J Guttmann1 1Anästhesiologische Universitätsklinik, Freiburg, Germany; 2Biomedical Engineering, HFU, Villingen-Schwenningen, Germany Critical Care 2007, 11(Suppl 2):P190 (doi: 10.1186/cc5350) Introduction The analysis of the nonlinearity of respiratory compliance to guide ventilator settings in ALI and ARDS is well S77 P191 Alveolar microscopy: on the automatic determination of alveolar size during ventilation D Schwenninger1, K Moeller1, C Stahl2, S Schumann2, J Guttmann2 1Furtwangen University, Villingen-Schwenningen, Germany; 2University of Freiburg, Germany Critical Care 2007, 11(Suppl 2):P191 (doi: 10.1186/cc5351) Alveolar microscopy: on the automatic determination of alveolar size during ventilation The user has to provide a pointer to the alveoli that shall be traced and whose changes in size and shape are to be determined. Filters, smoothing splines and expectation-driven fine tuning is performed to achieve robust and predictable results of the intratidal change in alveolar geometry. Results Animal studies related to alveolar mechanics during artificial ventilation were conducted. Figure 1a shows a plot of a frame taken from a video obtained during an experiment performed on a healthy anesthetized rat. Overlaid circles indicate identified boundaries of a selected alveolus. Figure 1b presents a trace of alveolar diameter during a tidal breath. Evaluation of successive Results Ventilatory parameters clearly showed a recruitment of nonaerated lung areas at the descending part of the pressure ramp. The shape of the P–V curve from EIT data, in particular the increasing slope (lower level > upper level), reflected the recruitment of poorly ventilated lung regions. The flattening of the curve at higher pressures, especially at the upper level, reflected less amount of recruitment but more overdistension. Regional pulmonary recruitment/derecruitment was very high in the lower level. These phenomena were more impressive after induced lung injury. Figure 1 (abstract 191) (a) Marked areas of a traced alveolus. (b) Changes in diameter during ventilation. Figure 1 (abstract 191) Conclusions Stepwise PEEP recruitment maneuvers can open collapsed lungs and certain PEEP levels are necessary to keep the lungs open. Monitoring of ∆V EIT is capable of detecting the dynamic process of recruitment and derecruitment at bedside. Plotting regional P–V curves from EIT data provides continuous information that may be of use in determining the PEEP level to maintain recruitment in acute lung injury. (a) Marked areas of a traced alveolus. (b) Changes in diameter during ventilation. 1. Victorino et al.: Am J Respir Crit Care Med 2004, 169:791- 800. frames allows one to compensate for motion artifacts and to analyze the intratidal changes in alveolar geometry. Conclusion Given a synchronization with respiratory data, this tool will allow one to quantify pressure-related changes of alveolar size. Thus it will allow one to monitor the alveolar distension in a variety of animal models (for example, lavage-induced ARDS) and to correlate these findings, for example, with outcome. References 1. Schiller et al.: Crit Care Med 2001, 29:1049-1055. 2. Stahl CA, et al.: Crit Care 2006, 10(Suppl 1):S2. 1. Schiller et al.: Crit Care Med 2001, 29:1049-1055. H Knorpp1, C Stahl2, S Schumann2, M Lichtwarck-Aschoff3, J Guttmann2 1UT Southwestern, Dallas, TX, USA; 2University of Freiburg, Germany; 3Zentralklinikum, Augsburg, Germany Critical Care 2007, 11(Suppl 2):P193 (doi: 10.1186/cc5353) 2. Stahl CA, et al.: Crit Care 2006, 10(Suppl 1):S2. Nonlinearity of intratidal airway resistance H Knorpp1, C Stahl2, S Schumann2, M Lichtwarck-Aschoff3, J Guttmann2 1UT Southwestern, Dallas, TX, USA; 2University of Freiburg, Germany; 3Zentralklinikum, Augsburg, Germany Critical Care 2007, 11(Suppl 2):P193 (doi: 10.1186/cc5353) Introduction Acute respiratory distress syndrome is a disease associated with high mortality. Understanding the interdependence S78 Available online http://ccforum.com/supplements/11/S2 Figure 1 (abstract P194) Figure 1 (abstract P194) Figure 1 (abstract P193) objective of this study was to evaluate plasma cytokine behavior after an ARM in healthy volunteers. Methods After obtaining ethical committee approval and informed consent, a basal blood sample was collected in 10 healthy volunteers. Continuous positive airway pressure (CPAP) was noninvasively applied (BiPAP Vision®; Respironics, USA) using a total face mask. CPAP was increased by 3 cmH2O from 5 to 20 cmH2O every five breaths. At CPAP of 20 cmH2O, an inspiratory pressure of 20 cmH2O above CPAP was implemented during 10 breaths. After that, CPAP was stepwise decreased in an inverse fashion. Pulse oximetry, arterial pressure and heart rate were measured before and after ARM. Additional blood samples were drawn at 30 minutes, 2 and 12 hours. TNFα, IL-1β, IL-6, IL-8, IL-10 and IL-12 were measured by the flow cytometry technique (Cytometric Bead Array BD™ Kit). The highest cytokine value at 30 minutes or 2 hours after ARM was considered the peak value measurement. Data were analyzed using a paired t test and one- way RM ANOVA. P < 0.05 was significant. of ventilator settings and respiratory mechanics is crucial for further developments of protective lung ventilation. Up to now, the nonlinearity of compliance has mainly been the focus of interest. We hypothesized that airway resistance also changes intratidally. Therefore, this study was performed to analyze the dependence of resistance on tidal gas volume. Methods After induction of anesthesia and tracheotomy, the lungs of 14 surfactant-depleted piglets were ventilated at zero end- expiratory pressure with three different tidal volumes (8, 12, 16 ml/kg) in a randomized order. In addition, baseline measurements (12 ml/kg) were performed before saline lavage. Before any change of the ventilator settings a recruitment maneuver was performed. The nonlinear intratidal airway resistance was analyzed using the SLICE method [1]. Results Figure 1 shows the intratidal resistance before lavage (grey) and after surfactant depletion (black) plotted against the alveolar pressure. Each curve in the diagram represents the intratidal course of resistance for one ventilator setting. P194 K Moeller1, T Sivenova1, C Stahl2, S Schumann2, J Guttmann2 1Furtwangen University, Villingen-Schwenningen, Germany; 2University of Freiburg, Germany Critical Care 2007, 11(Suppl 2):P195 (doi: 10.1186/cc5355) P195 Recruitment/derecruitment models fitted to respiratory data of acute respiratory distress syndrome/acute lung injury patients Nonlinearity of intratidal airway resistance Resistance is increased after surfactant depletion and is intratidally declining before and after lavage. Results Four men and six women with a mean age of 26 ± 1 years and mean BMI of 23.8 ± 3.6 kg/m2 were studied. No changes were observed in heart rate or MAP after ARM, while pulse oximetry increased from 97.2 ± 0.8% to 98.4 ± 0.7% (P = 0.009). As shown in Figure 1, ARM induced a significant increase in the peak plasma level concentration of all cytokines that returned to basal levels within 12 hours. No adverse effects were observed during and after ARM. Conclusion The analysis of resistance shows a dependence on intratidal volume. The nonlinear course of intratidal resistance can be interpreted as a volume-related caliber effect leading to an increase of cross-sectional area of the large and small airways. Conclusions Despite beneficial effects in reversing atelectasis, ARM-induced lung stretching was associated with an inflammatory response in healthy volunteers. Reference 1. Guttmann J, Eberhard L, Fabry B, et al.: Determination of volume-dependent respiratory system mechanics in mechanically ventilated patients using the new slice method. Technol Health Care 1994, 2:175-191. Noninvasive alveolar recruitment maneuver induces cytokine release in healthy volunteers The FRC, ratio (PaO2/FiO2) and static compliance (Cstat) are registered in three clinical steps: 1: ICU arrival; 2: after pulmonary recruitment with high inspiratory pressure; and 3: 3 hours after recruitment. Data are shown as the mean ± standard deviation; intragroup variables are analyzed with the Wilcoxon test (W), and intergroups variables are analyzed with the Mann–Whitney test (MW). P < 0.05 is taken as statistically significant. Results A multistep optimization process is performed to reduce the difference between measured data and model prediction. At any moment during a tidal breath or during some respiratory maneuver the current state of the model can be visualized. The inflated volume splits up into extension of open alveoli and into temporal or pressure-dependent recruitment. Distribution of these compartments over time during a tidal inflation is depicted in Figure 1a. The pressure vs time and flow vs time curves are shown in Figure 1b. Conclusion The fitting of recruitment models provides interesting insight into not directly observable R/D. It may be used for monitoring trends and drifts in recruitment. Currently results rely on certain assumptions; for example, distribution and quantity of superimposed pressure. With modern imaging techniques (for example, CT, EIT) a validation of the fitted models will come into reach and will be performed as a next step. Results FRC increase in group A is statistically significant (W) (step 1: 1,525 ± 360 ml; step 2: 1,937 ± 583 ml, P < 0.05 vs step 1; step 3: 2,592 ± 659 ml, P < 0.05 vs step 2 and P < 0.01 vs step 1) while the FRC increase in group B is not significant (step 1: 1,697 ± 210 ml; step 2: 1,757 ± 367 ml; step 3: 1,982 ± 365 ml); the FRC of group A is statistically higher than the FRC of group B in step 2 (P < 0.05 MW) and in step 3 (P < 0.01 MW). Noninvasive alveolar recruitment maneuver induces cytokine release in healthy volunteers Noninvasive alveolar recruitment maneuver induces cytokine release in healthy volunteers L Malbouisson1, T Szeles1, C Carvalho1, P Pelosi2, M Carmona1, J Auler1 1São Paulo University Medical School, São Paulo, Brazil; 2University of Insubria, Varese, Italy Critical Care 2007, 11(Suppl 2):P194 (doi: 10.1186/cc5354) Introduction Recruitment/derecruitment (R/D) seems to play an important role in the development of VILI [1]. Many clinicians base their determination of PEEP settings during mechanical ventilation of ARDS/ALI patients on an estimate of alveolar recruitability [2]. This project aims to establish an online tool that provides estimates of R/D in patients at the bedside. Introduction Recruitment/derecruitment (R/D) seems to play an important role in the development of VILI [1]. Many clinicians base their determination of PEEP settings during mechanical ventilation of ARDS/ALI patients on an estimate of alveolar recruitability [2]. This project aims to establish an online tool that provides estimates of R/D in patients at the bedside. Introduction Alveolar recruitment maneuver (ARM) using high airway pressures has been shown to re-expand atelectasis and to improve gas exchanges after general anesthesia; however, ARM may lead to lung stretching-induced inflammatory response. The Introduction Alveolar recruitment maneuver (ARM) using high airway pressures has been shown to re-expand atelectasis and to improve gas exchanges after general anesthesia; however, ARM may lead to lung stretching-induced inflammatory response. The Methods We developed a computer simulation of R/D based on Matlab (Mathworks, Natick, MA, USA), which incorporates different S79 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine Figure 1 (abstract P195) Figure 1 (abstract P195) Figure 1 (abstract P195) recruitment range (group A) and in patients with low recruitment range (group B). approaches [1,3,4]. Our model is fitted (currently offline) to patient data acquired during controlled mechanical ventilation. For data acquisition the internal respiratory data of a ventilator (Evita 4; Dräger Medical, Lübeck, Germany) is read in real time. The simulation assumes a quantitative partition into pressure- dependent and time-dependent recruitment. Pure pressure-related approaches (for example [1]) are not able to describe transients (for example, a volume shift after a change in PEEP). Methods Five patients without pulmonary disease (group A) admitted to the ICU for a postoperative course and five patients admitted to the ICU for acute respiratory failure (group B) were studied with the Engström Carestation FRC system based on the evaluation of nitrogen wash-in and washout by the COVX metabolic module. References 1. Hickling KG: Am J Respir Crit Care Med 2001, 163:69-78. 2. Gattinoni L, et al.: N Engl J Med 2006, 354:1775-1786. 3. Bates JH, et al.: J Appl Physiol 2002, 93:705-713. 4. Möller K, et al.: Crit Care 2005, 9(Suppl 1):S44-S45. 1. Hickling KG: Am J Respir Crit Care Med 2001, 163:69-78. 2. Gattinoni L, et al.: N Engl J Med 2006, 354:1775-1786. 3. Bates JH, et al.: J Appl Physiol 2002, 93:705-713. 4. Möller K, et al.: Crit Care 2005, 9(Suppl 1):S44-S45. 3. Bates JH, et al.: J Appl Physiol 2002, 93:705-713. 4. Möller K, et al.: Crit Care 2005, 9(Suppl 1):S44-S45. Noninvasive alveolar recruitment maneuver induces cytokine release in healthy volunteers The ratio increase in group A is statistically significant (W) (step 1: 256 ± 133; step 2: 407 ± 187, P < 0.01 vs step 1; step 3: 379 ± 169, P < 0.05 vs step 1) while the ratio increase in group B is not significant (step 1: 194 ± 50; step 2: 253 ± 83; step 3: 276 ± 73); the ratio of group A is statistically higher than the ratio of group B in step 2 (P < 0.01 MW) and in step 3 (P < 0.05 MW). The Cstat increase in both groups is not significant, but in group A Cstat is statistically higher than Cstat of group B in every step (P < 0.05 MW) (step 1: 38 ± 2 ml/cmH2O for group A vs 28 ± 7 ml/cmH2O for group B; step 2: 44 ± 6 ml/cmH2O vs 36 ± 8 ml/cmH2O; step 3: 47 ± 5 ml/cmH2O vs 36 ± 8 ml/cmH2O). Conclusion With the limit of low sample size, these preliminary data suggest that the FRC evaluation system is a good parameter to optimize pulmonary recruitment and seems to be in a position to overcome the Cstat limit for the evaluation of pulmonary recruitable parenchyma. High-frequency oscillatory ventilation for trauma patients with acute respiratory distress syndrome who fail conventional mechanical ventilation High-frequency oscillatory ventilation for trauma patients with acute respiratory distress syndrome who fail conventional mechanical ventilation F Eng, M Ferri, S Rizoli, L Tremblay Sunnybrook Health Sciences Centre, Toronto, Canada Critical Care 2007, 11(Suppl 2):P197 (doi: 10.1186/cc5357) F Eng, M Ferri, S Rizoli, L Tremblay Sunnybrook Health Sciences Centre, Toronto, Canada Critical Care 2007, 11(Suppl 2):P197 (doi: 10.1186/cc5357) Introduction The purpose of this study is to report our clinical experience with high-frequency oscillatory ventilation (HFOV) for rescuing trauma patients with acute respiratory distress syndrome (ARDS) and severe hypoxemia despite optimal conventional ventilation. Experimental and clinical data suggest mechanical ventilation can contribute to mortality in ARDS, and modern ventilatory strategies require protective measures such as low tidal volume, low airway pressure and fraction of inspired oxygen (FIO2), which is not always possible with conventional ventilation. HFOV could be an alternative to achieve protective ventilation and adequate oxygenation. Methods Patients having a PO2/FiO2 ratio ≤150, PEEP >12 cm and FiO2 requirement ≥0.7 on VCV (6 ml/kg) were switched to HFOV. The initial continuous distending pressure (CDP) of HFOV was 5 cm above the mean airway pressure during VCV. Other HFOV settings were FiO2 1, bias flow 30 l/min, amplitude 70 cm and frequency 7 Hz. The CDP was adjusted to maintain oxygen saturation >88%. Fluid bolus before switching to HFOV was avoided. All the patients were sedated and paralysed during the study period. A drop in the mean arterial pressure (MAP) ≤65 mm or cardiac index (CI) ≤2.5 l/min/m2 were treated with escalation of inotrope if required. Hemodynamic monitoring was done with the Flotrac-Vigileo monitoring system. Methods We retrospectively analyzed nine trauma patients who presented with ARDS criteria and failed conventional mechanical ventilation requiring HFOV. The mean airway pressure was initially set 3–5 cmH2O higher than that for conventional ventilation and was subsequently adjusted to maintain oxygen saturation >90% and FiO2 <0.6. The PaCO2 target range was 35–60 mmHg with a pH >7.25. We collected demographic data, injury severity scale (ISS), APACHE II score, time to HFOV, time spent on HFOV, ventilation settings and arterial blood gas before and after HFOV and mortality. Results Eight ARDS patients needing vasopressor support were switched to HFOV from VCV. Baseline data of these patients were: age 58.87 ± 11.69 years, APACHE II score 21.02 ± 8.14, mean CDP of HFOV 26.67 ± 3.22 cm, frequency 7 Hz, amplitude 70 cm. P196 A novel system for evaluation of pulmonary functional residual capacity in the intensive care unit: preliminary data G Falzetti, T Principi, P Pelaia Anaesthesia and Intensive Care Clinic – Politechnical University of Marche, Ancona, Italy Critical Care 2007, 11(Suppl 2):P196 (doi: 10.1186/cc5356) Introduction The aim of this study is to evaluate the efficacy of pulmonary recruitment by the use of functional residual capacity (FRC) measurement with the Engström Carestation FRC INview™ system (GE Healthcare), in patients with high pulmonary S80 Available online http://ccforum.com/supplements/11/S2 Figure 1 (abstract P198) Figure 1 (abstract P198) Figure 1 (abstract P198) Outcome predictors of high-frequency oscillatory ventilation in acute respiratory distress syndrome S Jog, P Akole, P Rajhans, B Pawar Deenanath Mangeshkar Hospital and Research Centre, Pune, India Critical Care 2007, 11(Suppl 2):P199 (doi: 10.1186/cc5359) Conclusion HFOV is a possible alternative for safely correcting oxygenation failure associated with ARDS in trauma patients. Further research is necessary to identify the best strategy and patients for HFOV. Introduction Outcome predictors of high-frequency oscillatory ventilation (HFOV) in severe ARDS are not well studied. Objective To evaluate outcome predictors of HFOV in adult patients with ARDS. Introduction Outcome predictors of high-frequency oscillatory ventilation (HFOV) in severe ARDS are not well studied. Objective To evaluate outcome predictors of HFOV in adult patients with ARDS. Methods ARDS patients receiving mechanical ventilation as per the ARDSnet protocol with PO2/FiO2 <150, PEEP ≥12 cm and FiO2 ≥0.7 were considered for HFOV. The continuous distending pressure (CDP), frequency, amplitude, inspiratory time and bias flow of HFOV were optimised, guided by frequent blood gas analysis. Weaning from HFOV to pressure support ventilation was attempted once the PO2/FiO2 ratio remained ≥200 with CDP ≤18 cm FiO2 ≤0.5. Responders (R) were defined as patients who were successfully weaned to a state without any ventilatory support for >12 hours. Nonresponders (NR) could not be weaned off any ventilatory assistance. High-frequency oscillatory ventilation for trauma patients with acute respiratory distress syndrome who fail conventional mechanical ventilation Figure 1 presents the trends of hemodynamic parameters during the study period. Only one patient needed escalation of the dopamine dose during the trial period. Results Data on nine trauma patients were available for analysis; the severity of respiratory dysfunction can be estimated by the mean PaO2/FiO2 of our patients, 131. Two patients received a trial of inhaled nitric oxide as part of the management of ARDS failing conventional ventilation. The last mean measurements before initiation of HFOV were: pH 7.24, PaO2 116, PCO2 67.4, FiO2 0.899. No significant hemodynamic instability was associated with initiation and administration of HFOV. The mean frequency was 4.3 (mode 4), mean power was 8.5, mean FiO2 was 0.83. The successful weaning rate from HFOV to extubation or trach mask was 70%, and mean total time of mechanical ventilation (conventional + HFOV) was 347.76 hours and the time spent on HFOV was 107.5 hours. Conclusion Switching of an ARDS patient from VCV to HFOV does not impart significant hemodynamic instabilities and can be safely done. P197 P197 High-frequency oscillatory ventilation for trauma patients with acute respiratory distress syndrome who fail conventional mechanical ventilation F Eng, M Ferri, S Rizoli, L Tremblay Sunnybrook Health Sciences Centre, Toronto, Canada Critical Care 2007, 11(Suppl 2):P197 (doi: 10.1186/cc5357) pH: an overlooked criterion for success in high-frequency oscillatory ventilation in acute respiratory distress syndrome? pH: an overlooked criterion for success in high-frequency oscillatory ventilation in acute respiratory distress syndrome? K Madhusudana, K Black, C Melville Hull Royal Infirmary, Hull, UK Critical Care 2007, 11(Suppl 2):P201 (doi: 10.1186/cc5361) K Madhusudana, K Black, C Melville Introduction High-frequency oscillatory ventilation (HFOV) is used for patients with refractory hypoxia and or severe oxygenation failure in our ICU. There is a unit policy regarding the timing of initiation of HFOV, and all patients were initiated with a single static recruitment manoeuvre and then managed according to local guidelines. The aim of this study was to understand which ventilatory parameters best predicted successful outcome following HFOV. that in the NR group. The difference in improvement in the oxygenation index (OI) of the two groups at 6 and 24 hours was also statistically significant. The rate of improvement in the PO2/FiO2 ratio and OI in NR was slower than that in R, and this difference was statistically significant (trend test). See Figure 1. Conclusion A lower PO2/FiO2 ratio and higher OI prior to HFOV and slow improvement in the PO2/FiO2 ratio and OI at 6 and 24 hours on HFOV are significant negative outcome predictors of HFOV in ARDS. that in the NR group. The difference in improvement in the oxygenation index (OI) of the two groups at 6 and 24 hours was also statistically significant. The rate of improvement in the PO2/FiO2 ratio and OI in NR was slower than that in R, and this difference was statistically significant (trend test). See Figure 1. y g g Conclusion A lower PO2/FiO2 ratio and higher OI prior to HFOV and slow improvement in the PO2/FiO2 ratio and OI at 6 and 24 hours on HFOV are significant negative outcome predictors of HFOV in ARDS. Methods After institutional approval, we retrospectively reviewed the case notes all the adult patients who were ventilated with HFOV during the 18-month period between January 2005 and July 2006. The data were analysed using SPSS® version 13 software. Results There were 33 episodes of HFOV in 31 patients; 19 females and 12 males; mean age of 56 years. First-day median APACHE II scores and predicted mortality were 23 and 41%, respectively. All the patients had acute respiratory distress syndrome (ARDS) at the time of initiation of HFOV. pH: an overlooked criterion for success in high-frequency oscillatory ventilation in acute respiratory distress syndrome? The main causes of ARDS were pneumonia leading to sepsis (50%), sepsis from other sources (18%), postoperative emergency laparotomy and abdominal aortic aneurysm repair (18%). Patients were ventilated with conventional ventilation for a median period of 35 hours (0–519 hours) before being ventilated with HFOV for a median period of 58 hours (7–1,080 hours). Fourteen patients (45%) were successfully weaned to conventional ventilation while two (7%) died because of cardiac arrest and in the remaining 15 patients (48%) treatment was withdrawn. Eight patients (25.8%) survived to discharge to the ward. An admission pH of less than 7.20 was found to be significantly associated (P = 0.09) with failure of treatment. P200 Monitoring slow recruitment manoeuvres with high- frequency oscillatory ventilation in adult acute respiratory distress syndrome patients using electrical impedance tomography L Camporota, J Smith, K Lei, T Sherry, R Beale Guy’s and St Thomas’ NHS Foundation Trust, London, UK Critical Care 2007, 11(Suppl 2):P200 (doi: 10.1186/cc5360) Monitoring slow recruitment manoeuvres with high- frequency oscillatory ventilation in adult acute respiratory distress syndrome patients using electrical impedance tomography L Camporota, J Smith, K Lei, T Sherry, R Beale Guy’s and St Thomas’ NHS Foundation Trust, London, UK Critical Care 2007, 11(Suppl 2):P200 (doi: 10.1186/cc5360) Introduction Recruitment manoeuvres (RM) during high-frequency oscillatory ventilation (HFOV) are increasingly used in ARDS. However, the changes in lung volume during a RM (lung recruitability) are difficult to quantify at the bedside, and the use of CT is impractical in patients on HFOV. We studied the effects of a standardised protocol of slow RM (SRM) on regional lung volumes assessed noninvasively by electrical impedance tomography (EIT). Methods SRM were performed by progressive increases of continuing distending pressure (CDP) starting from the mean airway pressure on CMV + 5 cmH2O, by increments of 3 cmH2O every 10 minutes until a CDP of 50 cmH2O was reached or haemo- dynamic instability ensued. Subsequently, CDP was reduced by 2 cmH2O every 5 minutes until optimal CDP was established on gas exchange. EIT measurements were performed using 16 electrodes, acquired via the Goe-MF II EIT system (Viasys Healthcare, USA). Offline analysis of EIT measurements was performed using the AUSPEX software (University of Amsterdam). Changes in impedance (∆Z) during tidal breathing were calibrated against set tidal volumes during conventional mechanical ventilation. Changes in lung volume after each increase in CDP on HFOV were expressed as the fold change compared with the previous CDP level. Conclusion Although we believed that the unit’s approach to HFOV was one of ‘treatment’ rather than ‘rescue’, our results suggest we are still using HFOV in a ‘rescue’ mode. While our results support the findings of other studies that earlier initiation of HFOV shows a trend towards improved outcome in adult patients with ARDS, further studies are still required to identify appropriate parameters for selecting patients in a timely manner who may benefit from HFOV. However, progressive acidosis in ARDS appears to be a relatively more important predictive criterion than parameters of failing oxygenation and ventilation. P202 Acoustic monitoring of one-lung ventilation with vibration response imaging Hemodynamic effects of high-frequency oscillatory ventilation in acute respiratory distress syndrome Hemodynamic effects of high-frequency oscillatory ventilation in acute respiratory distress syndrome S Jog, P Akole, S Gadgil, P Rajhans Deenanath Mangeshkar Hospital and Research Centre, Pune, India Critical Care 2007, 11(Suppl 2):P198 (doi: 10.1186/cc5358) Introduction High-frequency oscillatory ventilation (HFOV) is a promising ventilatory modality for ARDS patients having refractory hypoxemia despite standard ARDS ventilation. Hemodynamic alterations while switching the patient from volume-controlled ventilation (VCV) to HFOV are not yet well studied. Introduction High-frequency oscillatory ventilation (HFOV) is a promising ventilatory modality for ARDS patients having refractory hypoxemia despite standard ARDS ventilation. Hemodynamic alterations while switching the patient from volume-controlled ventilation (VCV) to HFOV are not yet well studied. Results Fifteen out of the total 28 patients were R and 13 were NR. Both the groups were similar prior to HFOV in terms of APACHE II score, number of organ failures, PEEP and plateau pressures, and duration of ventilation before HFOV. The baseline PO2/FiO2 ratio and improvement in it at 6 hours and 24 hours in the R group were statistically significantly higher as compared with Objective To evaluate immediate (within 3 hours) hemodynamic effects of HFOV in ARDS patients with septic shock needing vasopressor support. S81 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine Figure 1 (abstract P199) VCV, volume controlled ventilation. Figure 1 (abstract P199) Conclusion EIT can noninvasively assess lung recruitability and quantify the changes in global and regional lung volume during SRM with HFOV in ARDS patients. Conclusion EIT can noninvasively assess lung recruitability and quantify the changes in global and regional lung volume during SRM with HFOV in ARDS patients. Correlation of lung vibration and airflow Figure 2 (abstract P202) S Jean, I Cinel, C Tay, Z Wang, D McGinly Robert Wood Johnson School of Medicine, UMDNJ, Cooper University Hospital, Camden, NJ, USA Critical Care 2007, 11(Suppl 2):P203 (doi: 10.1186/cc5363) Introduction Airflow into a mechanically ventilated patient is easily measured in the inspiratory limb of the ventilator. Regional airflow inside the lungs, up to this point, is a black box. Vibration response imaging (VRI) is a novel technology that measures vibration energy from the lungs to create a real-time structural and functional image of regional vibration during respiration. Sophisticated surface skin sensors are placed on the subject’s back to record, analyze and display vibrations noninvasively. Our goal was to assess the correlation of vibration measured at the chest wall with airflow into the lungs. Methods To assess the effect of constant inspiratory flow on lung vibration, VRI was performed on a mechanically ventilated patient on assist volume control, and airflow in the tubing was recorded concurrently. To assess the effect of increasing flow rates on lung vibration, healthy subjects were recorded several times with VRI while taking tidal volumes of 200–1,300 ml at the same respiratory rate. The inspiratory tidal volume was recorded. Figure 2 (abstract P202) Figure 2 (abstract P202) S83 Figure 1 (abstract P203) Figure 2 (abstract P203) Figure 1 (abstract P203) Figure 2 (abstract P203) Figure 1 (abstract P203) Figure 1 (abstract P203) inaccurate for the detection of OLV with a high margin, up to 60% error [1]. Vibration response imaging (VRI) is a novel technology that measures vibration energy from the lungs and displays regional intensity in both visual and graphic format. The time from the start of the procedure to display takes less than 1.5 minutes. We investigated the effectiveness of VRI to detect OLV using a double-lumen endotracheal tube in lung surgery patients. Methods Double-lumen tubes were placed at the time of surgery. Tracheal and endobronchial lumens were alternately clamped to produce unilateral lung ventilation of the right and left lungs. VRI was performed after each occlusion. Two images were excluded a priori (prior to analysis) due to technical failure (external artifact). Figure 2 (abstract P203) Figure 2 (abstract P203) S83 Results The right and left lung distribution of vibration intensity is shown in Figure 1. P203 Correlation of lung vibration and airflow Acoustic monitoring of one-lung ventilation with vibration response imaging Results Four patients with ARDS, who underwent rescue HFOV, were enrolled. Following the SRM, there was a mean 2.38-fold increase in PaO2/FiO2 and a 19.7% reduction in PaCO2. EIT showed a mean 4.66-fold increase in global lung volume, with preferential ventilation of the ventral regions (59.4% of global volume change). Despite these differences, both dorsal and ventral regions showed a similar degree of volume change compared with their own baseline (V/D of 4.7/4.5-fold). This may be consistent with a more homogeneous recruitment with HFOV. The inflation limb of the changes in lung volumes during SRM fitted the Venegas–Harris equation (r2 = 0.99). I Cinel, S Jean, I Gratz, E Deal, C Tay, J Littman Robert Wood Johnson School of Medicine, UMDNJ, Cooper University Hospital, Camden, NJ, USA Critical Care 2007, 11(Suppl 2):P202 (doi: 10.1186/cc5362) Introduction Inadvertent endobronchial intubation and one-lung ventilation (OLV) with a standard endotracheal tube may lead to serious complications, such as a nonventilated lung, pneumothorax and hypoxemia. Auscultation of breath sounds was found to be Introduction Inadvertent endobronchial intubation and one-lung ventilation (OLV) with a standard endotracheal tube may lead to serious complications, such as a nonventilated lung, pneumothorax and hypoxemia. Auscultation of breath sounds was found to be S82 Available online http://ccforum.com/supplements/11/S2 P203 Figure 1 (abstract P202) P205 Functional residual capacity measurement during mechanical ventilation in order to find the optimal positive end-expiratory pressure Introduction Focusing on lung-protective ventilation, the analysis of nonlinear dynamic respiratory mechanics appears crucial. Based on the SLICE method we developed the Gliding-SLICE method as a tool to determine respiratory system mechanics. This tool was tested in a nonlinear water-filled two-chamber lung model. I Bikker, D Reis Miranda, J Van Bommel, J Bakker, D Gommers Erasmus MC, Rotterdam, The Netherlands Critical Care 2007, 11(Suppl 2):P205 (doi: 10.1186/cc5365) Introduction In patients with ALI/ARDS, a protective ventilation strategy has been introduced in order to diminish ventilator- induced lung injury. It has become clear that these patients require sufficient levels of PEEP to prevent alveolar derecruitment, but also not too much PEEP that alveolar overdistension occur. To achieve the optimal level of PEEP in patients with ALI/ARDS, different concepts have been introduced. GE Healthcare, along with Dr Ola Stenqvist, has developed a technology to measure functional residual capacity (FRC) in ventilated patients without interruption of the ventilation. The aim of this study was to test the feasibility of this device and to test whether decreasing the PEEP affects FRC in mechanically ventilated patients with and without lung disease. Methods The classic SLICE method [1] determines parameters of the respiratory system for abutted volume ranges. The Gliding- SLICE method enhances this method by moving a window of analysis along the volume axis. This way, a quasi-continual course of intratidal mechanics can be determined. To test the new method we build up a physical model that consists of two connected chambers filled with water. During inspiration water is displaced from one chamber to the other resulting in a counter pressure. Using wedges of certain shapes we simulated volume-dependent nonlinear compliances. Results Using the Gliding-SLICE method we determined a nonlinear course of compliance in a patient (Figure 1) and in model data (Figure 2). Methods For this survey we examined 10 patients under mechanical ventilation. The FRC examinations were performed with the Engström Carestation equipped with the FRC Inview™ monitoring feature. FRC is determined using the change of lung nitrogen volume after a step change in the inspired oxygen fraction. With this system, there is no need to use supplementary gases or specialized gas monitoring devices. Furthermore, a series of FRC measurements can automatically be obtained at different PEEP levels that can be chosen prior to the measurement. Correlation of lung vibration and airflow The mean percentage change of vibration intensity clearly demonstrates the increased vibration in ventilated lungs (89.1 ± 5.47% vs 10.9 ± 5.4%, P < 0.05) (Figure 2). Conclusions Auscultation is insensitive to endobronchial intubation and chest radiography may not be immediately available. VRI offers the potential to rapidly and noninvasively determine endobronchial intubation. Currently VRI is performed in the sitting position, but the capability of supine imaging will soon be available. Reference 1. Brunel W, et al.: Assessment of routine chest roentgenograms and the physical examination to confirm endotracheal tube position. Chest 1989; 96:1043-1045. S83 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Reference 1. Guttmann et al.: Technol Health Care 1994, 2:175-191. Figure 2 (abstract P204) Figure 2 (abstract P204) Figure 2 (abstract P204) Results In the mechanically ventilated patient, when there is minimal flow, the vibration was at its lowest. When flow begins at the ventilator, the vibration measured over the lungs increases and when the flow stops, the vibration decreases. An inspiratory hold was performed to separate inspiratory from expiratory vibrations (Figure 1). As the subject takes increasing tidal volumes, the vibration during the breath cycle increases linearly. A sample subject is shown in Figure 2 (R2 = 0.81). Conclusion Vibration measured using VRI correlates with lung airflow. Given the difficulty in assessing airflow in the lungs, measuring lung vibration could potentially serve as a surrogate for regional lung airflow. P204 The Gliding-SLICE method: an enhanced tool for estimation of intratidal respiratory mechanics Reference Reference 1. Guttmann et al.: Technol Health Care 1994, 2:175-191. S Schumann1, C Stahl1, D Steinmann1, K Möller2, J Guttmann1 1University Hospital, Freiburg, Germany; 2HFU, Furtwangen, Germany Critical Care 2007, 11(Suppl 2):P204 (doi: 10.1186/cc5364) P205 During this procedure, all ventilator settings will remain constant other than the FiO2 and the PEEP settings. In patients with ALI, the PEEP was decreased from 25 to 5 cmH2O in five steps and the FRC was measured. In the patients without lung disease, PEEP was decreased from 15 to 0 cmH2O in four steps and the FRC was measured. Conclusion The Gliding-SLICE method allows one to calculate mechanical parameters of the respiratory system quasi-continually. This allows a more intuitive interpretation of data. The method is not limited to principle constrictions but can be enhanced by ventilatory maneuvers; for example, for separated view on inspiratory and expiratory respiratory mechanics. P208 Dry powder nebulization of a recombinant surfactant protein C-based surfactant for treatment of acute respiratory distress syndrome C Ruppert, T Kuchenbuch, S Schmidt, P Markart, T Gessler, T Schmehl, W Seeger, A Guenther University of Giessen Lung Center, Giessen, Germany Critical Care 2007, 11(Suppl 2):P208 (doi: 10.1186/cc5368) Results The R-squared (R2) values for the correlation between lnPaO2 and %Vnon of lung and the slice combinations juxta, 3new and 3old were 0.61, 0.60, 0.57 and 0.55, respectively. The %Vnon of lung correlated best with the %Vnon of slice combinations juxta and 3new (R2 = 0.96 and 0.95, respectively). Comparison of these slice combinations with lung also resulted in the least bias in the Bland–Altman analyses (6.3 and 5.9%, respectively). R2 for the correlation between lung and 3old was 0.93, and the bias for lung vs 3old in the Bland–Altman analysis was 6.8%. Introduction Nebulization of pulmonary surfactant for treatment of ARDS represents a desirable therapeutic approach but was hitherto impossible under clinical conditions due to the technical limitations of currently available devices. In the present study we investigated a new dry powder nebulizer for administration of a recombinant surfactant protein C (rSP-C)-based surfactant. Introduction Nebulization of pulmonary surfactant for treatment of ARDS represents a desirable therapeutic approach but was hitherto impossible under clinical conditions due to the technical limitations of currently available devices. In the present study we investigated a new dry powder nebulizer for administration of a recombinant surfactant protein C (rSP-C)-based surfactant. y Conclusion Depending on the precision required, the use of single juxtadiaphragmatic CT slices can help to speed up the analysis process and thereby propel the clinical implementation of CT- derived information. Our data suggest that juxtadiaphragmatic slices may be better suited than the ‘traditional’ combination of apical, hiliar and juxtadiaphragmatic slices. Methods The nebulizer device consists of a cylindrical glass housing that, at the bottom, ends up in a spherical lower housing part that serves as the dry powder reservoir. A gas inlet portion with a nozzle at its end is coaxially aligned with the housing, almost reaches the bottom of the dry powder reservoir, and induces aerosol generation when gas pressures between 1 and 2 bar are applied. The upper portion of the housing contains a cap with an aerosol exit port. Several nozzles ensure a discharge of unsuitably large aerosol particles. Aerosol characteristics were determined by laser diffractometry. Available online http://ccforum.com/supplements/11/S2 Results At Time 1, the control group (n = 21) had ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/ FiO2) and partial arterial carbon dioxide pressure (PaCO2) of 167.7 ± 56.2 and 40.3 ± 10.1, respectively, and the intervention group (n = 19) had PaO2/FiO2 of 180.5 ± 67.0 and PaCO2 of 38.6 ± 10.5. At Time 2, the control group had, respectively, PaO2/ FiO2 and PaCO2 of 165.9 ± 63.8 and 38.9 ± 10.3, and the inter- vention group of 177.2 ± 4.5 and 39.0 ± 10.8. No variable was signifi- cantly different between the groups at Time 1 and Time 2 (P > 0.05). Conclusion The proposed maneuver was not beneficial for gas exchange in the sample studied. Methods The patients with the diagnosis of ALI and ARDS who met the inclusion criteria were randomized to one of the two groups: those of the intervention group were subjected to a pulmonary expansion and bronchial disobstruction maneuvers, for approximately 10 minutes by the association of the following physiotherapy techniques: sighs, side-lying position, expiratory rib-cage compression and endotracheal suctioning with a closed system and after observed for 10 minutes; the patients of the control group did not receive any treatment, they were only observed for 20 minutes. Ventilatory parameters and arterial blood gases were measured before (Time 1) and 10 minutes after the procedures (Time 2). The analysis of variance test for repeated measurements was used for comparing variables at different times. Results are shown as the mean and standard deviation. The significant level was P < 0.05. P208 The efficacy of an inhalative rSP-C surfactant application was assessed in three animal models of acute lung injury, including rabbits with acute lung injury due to either repetitive lavage with prolonged and injurious ventilation, or due to inhalative application of bleomycin at day 4, and bleomycin- challenged, spontaneously breathing mice. Analysis of the nonaerated lung volume in combinations of single computed tomography slices – is extrapolation to the entire lung feasible? Analysis of the nonaerated lung volume in combinations of single computed tomography slices – is extrapolation to the entire lung feasible? AW Reske, P Hepp, C Heine, K Schmidt, M Seiwerts, U Gottschaldt, AP Reske Universitaetsklinikum Leipzig, Germany Critical Care 2007, 11(Suppl 2):P206 (doi: 10.1186/cc5366) Introduction The nonaerated lung volume (Vnon) can be quantified from computed tomography (CT) images. Analysis of the CT slices covering the entire lung is time-consuming and thus limits potential clinical and experimental applications. This could be improved by analyzing only a few representative CT slices. The number and ana- tomical location of CT images required for analyses that are represen- tative for the entire lung, however, is discussed controversially. Results At Time 1, the control group (n = 21) had ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/ FiO2) and partial arterial carbon dioxide pressure (PaCO2) of 167.7 ± 56.2 and 40.3 ± 10.1, respectively, and the intervention group (n = 19) had PaO2/FiO2 of 180.5 ± 67.0 and PaCO2 of 38.6 ± 10.5. At Time 2, the control group had, respectively, PaO2/ FiO2 and PaCO2 of 165.9 ± 63.8 and 38.9 ± 10.3, and the inter- vention group of 177.2 ± 4.5 and 39.0 ± 10.8. No variable was signifi- cantly different between the groups at Time 1 and Time 2 (P > 0.05). Conclusion The proposed maneuver was not beneficial for gas exchange in the sample studied. Methods The percentage of Vnon (%Vnon) relative to the total lung volume was quantified in CT-image series (n = 21) of sheep with gross anesthesia-induced atelectasis. This was performed for different combinations of number and anatomical location of CT slices and the results were compared with the %Vnon of the entire lung (lung). The combinations were: one juxtadiaphragmatic slice (juxta), three apical, hiliar and juxtadiaphragmatic slices (3old), and three consecutive juxtadiaphragmatic slices (3new). The correla- tion between %Vnon and the arterial oxygen partial pressure (PaO2) was examined for all combinations. The PaO2 was measured at the time of the CT and transformed logarithmically (lnPaO2) to linearize the relation between PaO2 and %Vnon. Linear regression and Bland–Altman plots were used for statistical analysis. Figure 1 (abstract P204) 2 p Results The best FRC measurements were obtained in well- sedated patients during controlled mechanical ventilation. During pressure support ventilation, a constant breathing pattern is necessary for accurate FRC measurements. In patients that received pressure support ventilation, FRC values were lower at the highest studied PEEP level. In two patients that received controlled ventilation, lower levels of FRC were found at the highest PEEP level but this was due to a pneumothorax that was diagnosed a day later. In patients with ALI, the FRC decreased after each PEEP reduction step. However, the FRC decreased more when PEEP was lowered from 15 to 10 cmH2O in these patients. In patients without lung disease, the FRC did not S84 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 decrease after PEEP was reduced from 15 to 5 cmH2O but decreased after PEEP was reduced from 5 to 0 cmH2O. Conclusion Accurate measurements of FRC are obtained during a constant breathing pattern that is easier to obtain during controlled ventilation in comparison with pressure-support ventilation. In patients with ALI/ARDS, the FRC decreased during each PEEP reduction, but whether the largest change in FRC indicates the optimal PEEP needs further research. decrease after PEEP was reduced from 15 to 5 cmH2O but decreased after PEEP was reduced from 5 to 0 cmH2O. Conclusion Accurate measurements of FRC are obtained during a constant breathing pattern that is easier to obtain during controlled ventilation in comparison with pressure-support ventilation. In patients with ALI/ARDS, the FRC decreased during each PEEP reduction, but whether the largest change in FRC indicates the optimal PEEP needs further research. few studies on the effect on gas exchange in patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) and physiotherapy techniques. The purpose of this study was to assess the effect of a pulmonary expansion and disobstruction maneuver with a closed system on the gas exchange of patients with ALI and ARDS. Conclusion Accurate measurements of FRC are obtained during a constant breathing pattern that is easier to obtain during controlled ventilation in comparison with pressure-support ventilation. In patients with ALI/ARDS, the FRC decreased during each PEEP reduction, but whether the largest change in FRC indicates the optimal PEEP needs further research. S Methods The patients with the diagnosis of ALI and ARDS who met the inclusion criteria were randomized to one of the two groups: those of the intervention group were subjected to a pulmonary expansion and bronchial disobstruction maneuvers, for approximately 10 minutes by the association of the following physiotherapy techniques: sighs, side-lying position, expiratory rib-cage compression and endotracheal suctioning with a closed system and after observed for 10 minutes; the patients of the control group did not receive any treatment, they were only observed for 20 minutes. Ventilatory parameters and arterial blood gases were measured before (Time 1) and 10 minutes after the procedures (Time 2). The analysis of variance test for repeated measurements was used for comparing variables at different times. Results are shown as the mean and standard deviation. The significant level was P < 0.05. P211 Results Fifty-eight critically ill patients undergoing mechanical ventilation were included. Following the BAL, compliance of the respiratory system (Crs) decreased from 50.9 ± 36.1 to 35.6 ± 14.8 ml/cmH2O (P < 0.01) and airway resistance increased from 16.2 ± 7.6 to 18.1 ± 11.3 cm H2O/l/seg (P < 0.05); 90 minutes later, both parameters had returned to pre-BAL values (P = not significant). Patients who showed >20% decrease in Crs had higher pre-BAL Crs than patients with less severe decrease (55.8 ± 20.1 vs 36.9 ± 14.1; P < 0.001). On the contrary, neither pre- BAL airway resistance nor the extension of the radiographic infiltrates were related to the changes in respiratory mechanics. P207 Pulmonary expansion and disobstruction maneuver with a closed system in patients with acute lung injury and acute distress syndrome, and its effect on gas exchange J Belato, S Barreto, C Santos, S Vieira Hospital de Clínicas de Porto Alegre, Brazil Critical Care 2007, 11(Suppl 2):P207 (doi: 10.1186/cc5367) Introduction Respiratory physiotherapy is ever more utilized for the treatment of critical patients. However, it is known that there are Introduction Respiratory physiotherapy is ever more utilized for the treatment of critical patients. However, it is known that there are Results The generated aerosol had a mass median aerodynamic diameter of 1.6 µm, with 85% of all particles being smaller than S85 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin lesions at the bedside in the emergency department is difficult. Clinical examination (CE) and chest X-ray (X-ray) have limited sensibility and specificity. Contrast-enhanced computed tomo- graphy (CT scan) is the gold standard. CT scan has limitations: it takes time to be performed, implies transport of severely injured patients, and has ionising effects. Thoracic ultrasonography (US) can be quickly performed at the bedside in the emergency room. It has good diagnosis accuracy in ARDS patients [2]. The purpose of this study is to evaluate the diagnosis accuracy of US in severely injured patients in the emergency room. 5 µm, and the average mass of surfactant being nebulized under these conditions was approximately 1 g/min. Biochemical and biophysical studies showed that the composition and surface tension reducing properties of the rSP-C surfactant remained unaltered after nebulization. In both rabbit models, administration of 130 mg/kg body weight rSP-C surfactant resulted in a far-reaching restoration of gas exchange and compliance. In bleomycin- challenged, spontaneously breathing mice, surfactant aerosoliza- tion resulted in a restoration of compliance. Conclusions Nebulizer characteristics and results from the in vivo studies suggest that the herein-described dry powder nebulizer might proffer for surfactant therapy of ARDS. Methods We prospectively evaluated 90 patients (median age: 41 (7–89) years) who were admitted to the emergency room of the Grenoble University Hospital over a period of 9 months. Pneumothorax, hemothorax and alveolar consolidation were diag- nosed by CE, X-ray and US. The physician who performed the US was not involved in the patient’s management. The diagnosis accuracy of each technique is compared with the CT scan interpreted by the radiologist. P209 Changes in respiratory mechanics after fiberoptic bronchoscopy with bronchoalveolar lavage in mechanically ventilated patients Á Estella García, A Gil Cano, J Díaz Monrove, I Monge García Critical Care Unit, Hospital of Jerez, Spain Critical Care 2007, 11(Suppl 2):P209 (doi: 10.1186/cc5369) Changes in respiratory mechanics after fiberoptic bronchoscopy with bronchoalveolar lavage in mechanically ventilated patients Á Estella García, A Gil Cano, J Díaz Monrove, I Monge García Critical Care Unit, Hospital of Jerez, Spain Critical Care 2007, 11(Suppl 2):P209 (doi: 10.1186/cc5369) Results Sixty percent of patients had a chest trauma IGS II 22 (8–104), ISS 20 (0–59), thorax AIS 2 (0–5), SOFA 1 (0–11), oxygen saturation at the entrance 100% (74–100), mechanical ventilation for 56% of patients. We studied 179 hemithorax. For hemothorax (n = 16), the sensitivity/specificity/positive predictive value/negative predictive values (%) were CE: 13/95/18/92; X-ray: 13/95/20/92; US: 63/95/56/96. For pneumothorax (n = 30), CE: 20/96/50/86; X-ray: 17/100/100/86; US: 53/93/62/91. For alveolar consolidation (n = 100), CE: 17/95/81/47; X-ray: 29/98/94/52; US: 69/82/83/67. Introduction Nonuniform findings have been reported about the effects of bronchoalveolar lavage (BAL) on respiratory mechanics. Objectives (1) To study the effects of BAL on respiratory mechanics in mechanically ventilated patients with suspected pneumonia, and (2) to find out whether these effects are related to the extension of radiographic infiltrate and preceding respiratory mechanics measurements. Introduction Nonuniform findings have been reported about the effects of bronchoalveolar lavage (BAL) on respiratory mechanics. Conclusion Ultrasonography has a better sensitivity than CE and X-ray with a comparable specificity. In the emergency room it is a reliable modality for the diagnosis of pneumothorax, hemothorax and alveolar consolidation in the severely injured patient. References Methods BAL was performed with 150 ml sterile isotonic saline in three aliquots of 50 ml. Respiratory mechanics (static compliance and airway resistance) was measured using the rapid airway occlusion technique immediately before and after the BAL and 90 minutes later. The heart rate, arterial blood pressure and body temperature were recorded continuously in all patients. Patients were classified according to the presence of unilateral or bilateral infiltrates. 1. Klein et al.: Anaesthesist 2006, 55:1172-1188. 2. Lichtenstein et al.: Anesthesiology 2004, 100:9-15. 1. Klein et al.: Anaesthesist 2006, 55:1172-1188. 2. Lichtenstein et al.: Anesthesiology 2004, 100:9-15. 1. Klein et al.: Anaesthesist 2006, 55:1172-1188. 2. Lichtenstein et al.: Anesthesiology 2004, 100:9-15. Prehospital emergency endotracheal intubation using the Bonfils intubation fiberscope C Byhahn1, R Breitkreutz1, S Viehmeyer1, F Walcher1, B Zwissler2 1J.W. Goethe-University Hospital, Frankfurt, Germany; 2Klinikum der Johann Wolfgang Goethe University, Frankfurt, Germany Critical Care 2007, 11(Suppl 2):P211 (doi: 10.1186/cc5371) Objective Difficult intubating conditions are prevalent in 7–10% of patients who require out-of-hospital emergency endotracheal intu- bation. Airway anatomy can further be deteriorated through trauma, bleeding, and the use of cervical spine (CS) immobilization collars. We evaluated the feasibility of the Bonfils intubation fiberscope for prehospital emergency endotracheal intubation. Conclusions (1) BAL in mechanically ventilated patients can lead to a significant but transitory deterioration on pulmonary mechanics characterized by a decrease in Crs and an increase in airway resistance. (2) Patients with better initial Crs showed the more severe affectation. p p g y Materials and methods The Bonfils intubation fiberscope (Karl Storz GmbH, Tuttlingen, Germany) is a reusable, rigid, straight fiberoptic device with a 40° curved tip, 40 cm long and 5 mm in diameter. A flexible eyepiece is mounted on the handle of the scope. The fiberscope has a connector that fits onto the 15-mm tracheal tube adapter and thereby allows oxygen insufflation. A cold light source or a small battery handle (powered by two 1.5 V alkaline batteries) can be attached to the stylet handle. The tip of the Bonfils intubation fiberscope is positioned just proximal to the tip of the attached endotracheal tube, thereby preventing the lens from being soiled with blood or secretions. Having adopted the Bonfils technique in our institution, we felt that because of its battery-powered light source the Bonfils intubation fiberscope could also be used in prehospital settings, independent of a P210 Diagnosis accuracy of thoracic ultrasonography in severely injured patients A Hyacinthe1, C Broux1, G Francony1, G Ferretti2, J Payen1, C Jacquot1 1Service de réanimation polyvalente et chirurgicale, CHU, Grenoble, France; 2Radiologie, CHU, Grenoble, France Critical Care 2007, 11(Suppl 2):P210 (doi: 10.1186/cc5370) A Hyacinthe1, C Broux1, G Francony1, G Ferretti2, J Payen1, C Jacquot1 1 Introduction Thirty-three percent of severely injured patients suffer from thoracic trauma [1]. Diagnosis of pleural and pulmonary Introduction Thirty-three percent of severely injured patients suffer from thoracic trauma [1]. Diagnosis of pleural and pulmonary S86 Available online http://ccforum.com/supplements/11/S2 Figure 1 (abstract P212) Airway equipment available on ICUs. A score of 6/6 is considered the minimum. Figure 1 (abstract P212) 110/220 V cold light source. After appropriate inhospital training with the Bonfils intubation in anesthetized patients, our hospital’s mobile emergency unit staffed with an emergency physician was equipped with a battery-powered Bonfils intubation fiberscope. Results During 123 missions, 15 adult patients underwent pre- hospital endotracheal intubation (cardiac arrest n = 9, multiple injuries n = 4, drug poisoning n = 1, pulmonary edema n = 1) with the Bonfils intubation fiberscope, the use of which was either planned (n = 13) or unplanned (n = 2). All intubations were successful in the first attempt, even in two cardiac arrest victims who had an unexpected difficult airway (Cormack&Lehane grade IV under direct laryngoscopy). In those patients with multiple injuries the cervical immobilization collar did not need to be unfastened or removed for endotracheal intubation. Sufficient retropharyngeal space – which is mandatory for sufficient use of the Bonfils – was created by a digital jaw thrust maneuver in the first three patients. Using a standard Mackintosh laryngoscope blade significantly enhanced ease of insertion of the Bonfils fiberscope and visualization of the glottic aperture, thereby decreasing the procedure time from 35–40 seconds to 20–25 seconds. Conclusion Despite this first promising series of in-the-field use, physicians and paramedics should familiarize themselves with the Bonfils device under optimal clinical conditions before using it under emergency or prehospital conditions. In our experience, the learning curve with the Bonfils device is steep, and 10 intubations supervised by an instructor usually prove effective for achieving sufficient skills to use the Bonfils on one’s own and under less optimal conditions. In summary, we believe that the Bonfils fiberscope will prove its value as an additional airway management device in both, emergency and prehospital settings. J Koyama Acknowledgement The Bonfils intubation fiberscope was generously provided by Karl Storz GmbH, Tuttlingen, Germany. Introduction Occasionally, rescuers are confronted with a hard situation to establish tracheal intubation compared with doctors in the anesthetic room. Especially in the confined space, the tracheal intubation must enter technical difficulties with any supporting device. This may be caused by the fact that there was no device developed specially from a standpoint in the clinical emergency use. Objective The AirWay Scope (AWS) is one of the newest intubation devices, manufactured using modern technology to alleviate the tracheal intubation in emergency scenes. The AWS is equipped with a full-colored CCD, a LCD monitor and a specially configured introducer guiding a tracheal tube into the glottis (Figure 1). The aim of this study is to confirm the potential of the AWS as an intubation-supporting device in emergency scenes. M th d Si d i h d ll d i P212 P210 Airway equipment available on ICUs. A score of 6/6 is considered the minimum. P213 Potential of the AirWay Scope for tracheal intubation in a confined space J Koyama Shinshu University, Matsumoto, Japan Critical Care 2007, 11(Suppl 2):P213 (doi: 10.1186/cc5373) Airway equipment on the intensive care unit for management of the unanticipated difficult intubation J Craig1, R Green1, B Kyle1, M Jonas2 1Poole General Hospital, Poole, UK; 2Southampton General Hospital, Southampton, UK Critical Care 2007, 11(Suppl 2):P212 (doi: 10.1186/cc5372) Introduction This study was designed to assess the ability of ICUs to deal with the unanticipated difficult intubation. The ICU is a location in which the incidence of difficult intubation has been found to be significantly higher than in theatre (8–22.5% vs 1.5%). Method We contacted all adult general ICUs in the South of England and invited the physician responsible for airway management to take part in a structured interview. The interview was designed to follow the Difficult Airway Society (DAS) guidelines. We designed six equipment-related questions that identified a unit as achieving the minimum levels of equipment necessary. These included availability of laryngoscopes, capnography, LMA/ILMA, and rescue techniques. Method Six doctors in the emergency department were enrolled in this study. All doctors have experienced using the AWS in cases on the operation table but have no experience in special situations such as patients on the ground (POG) or no space over the head of the patient (NSH). Doctors tried intubation with the AWS and Macintosh Laryngoscope (Mac) in the simulated POG and NSH situations using a Laerdal Airway manikin. Technical training was not carried out in advance. The NSH/Mac situation was not investigated because it was theoretically impossible. The time to intubate (TTI) was recorded. Method We contacted all adult general ICUs in the South of England and invited the physician responsible for airway management to take part in a structured interview. The interview was designed to follow the Difficult Airway Society (DAS) guidelines. We designed six equipment-related questions that identified a unit as achieving the minimum levels of equipment necessary. These included availability of laryngoscopes, capnography, LMA/ILMA, and rescue techniques. Result All doctors successfully established intubation in each situation, POG/Mac, POG/AWS and NSH/AWS. Although the intubation of a manikin having no space over the head was thought to be difficult without prior training, all doctors successfully achieved the intubation from the foot using the AWS. The TTI (s) was 12.0 ± 1.5 in POG/Mac, 7.4 ± 1.1 in POG/AWS and 12.9 ± 1.4 in NSH/AWS. The TTI with AWS in POG situation was significantly shorter than that with Mac (P = 0.0135). Results Forty-five of 51 units responded (88%). Mandatory equipment levels are shown in Figure 1. P213 Potential of the AirWay Scope for tracheal intubation in a confined space J Koyama Shinshu University, Matsumoto, Japan Critical Care 2007, 11(Suppl 2):P213 (doi: 10.1186/cc5373) J Koyama Shinshu University, Matsumoto, Japan Critical Care 2007, 11(Suppl 2):P213 (doi: 10.1186/cc5373) A comparison of two types of new bronchial blockers, Uniblocker™ and Coopdech endotracheal blocker tube, for one-lung ventilation during thoracoscopy T Iizuka1, M Tanno2, Y Hamada1, T Shiga1, Y Ohe1 1Toho University Medical Center Ohashi Hospital, Meguro, Tokyo, Japan; 2National Mito Medical Center, Mito, Japan Critical Care 2007, 11(Suppl 2):P214 (doi: 10.1186/cc5374) Methods Benchtop model. Four tracheal tubes (8 mm internal diameter) were studied; the LoTrach, Portex SoftSeal, Microcuff and Mallincrokdt HiLo Evac. The model trachea had an internal diameter of 2.4 cm and the cuff was inflated with a Tracoe constant pressure device. The cuff was overpressured while fluid was instilled above the cuff to a height of 50 cm. The stopwatch was started as the pressure was reduced to the test pressure of 30 cmH2O. The rate of fall of the resulting column of fluid was then measured. Introduction The purpose of this study was to compare the use of a wire-guided bronchial blocker, Uniblocker™ (Fuji Systems Corporation, Tokyo, Japan), with a spread type of bronchial blocker, Coopdech endotracheal blocker tube (Daiken Medical Corporation, Osaka, Japan), for lung isolation during elective thoracic surgical cases. Clinical study. Intubated patients underwent a staged recruitment manoeuvre while the intracuff pressure was maintained with a Tracoe cuff inflator. The PEEP was set to 15 cmH2O and then increased in 5 cmH2O increments every 5 seconds until 40 cmH2O was achieved. A second observer auscultated the anterior neck and the pressure at which air leak was heard was recorded. Two tubes were studied; LoTrach (at 80 cmH2O intracuff pressure = 30 cmH2O calculated wall pressure) and Portex Soft Seal (30 cmH2O). p g g g Materials and methods Twenty ASA I–II patients signed written informed consent before being enrolled into the study. We designed a prospective, randomized trial to compare the effectiveness of lung isolation among the two types of bronchial blockers: Uniblocker™ group (UBB; n = 10), and Coopdech endotracheal blocker tube group (CBB; n = 10). Patients were randomized to intubate with a single-lumen tube with concomitant use of a UBB or a CBB. Both groups were subdivided in two: bronchial blocker placed in the right mainstem bronchus (UBBR/CBBR), and in the left mainstem bronchus (UBBL/CBBL). Comparisons between groups included: (1) the number of unsuccessful placement attempts with the blinded insertion technique, (2) the number of malpositions of the devices, (3) the time required to place the device in the correct position, (4) surgical satisfaction with the lung deflation, (5) complications and (6) the quality of lung deflation. P214 A comparison of two types of new bronchial blockers, Uniblocker™ and Coopdech endotracheal blocker tube, for one-lung ventilation during thoracoscopy P215 Comparison of the LoTrach and the Portex Soft Seal cuff: tracheal wall pressure and fluid leakage in a benchtop study and a clinical study L Evans, M Blunt, C Arunachalam, P Young Queen Elizabeth Hospital, King’s Lynn, UK Critical Care 2007, 11(Suppl 2):P215 (doi: 10.1186/cc5375) Comparison of the LoTrach and the Portex Soft Seal cuff: tracheal wall pressure and fluid leakage in a benchtop study and a clinical study L Evans, M Blunt, C Arunachalam, P Young Queen Elizabeth Hospital, King’s Lynn, UK Critical Care 2007, 11(Suppl 2):P215 (doi: 10.1186/cc5375) Introduction The objective of the study is to demonstrate two methods of measuring tracheal wall pressure (in vitro and in patients), with the LoTrach (LVLP) cuff and with conventional high- volume low-pressure (HVLP) cuffs. The LoTrach (VTSL, Singapore) is a new tracheal tube designed for use for mechanical ventilation in the critically ill. The LoTrach has been shown to prevent the ubiquitous problem of micro-aspiration of secretions associated with conventional HVLP cuffs [1]. Aspiration prevention is achieved by the properties of the LoTrach’s low-volume low-pressure (LVLP) cuff, and these have been previously described [1,2]. It is important that, alongside achieving aspiration prevention, there is also tracheal wall pressure control. The LoTrach LVLP cuff is calibrated such that the sum of the elastic forces within the cuff remain constant throughout the inflation profile. Thus, at the working intra- cuff pressure of 80 cmH2O, only a consistent and acceptable 30 cmH2O is transmitted to the tracheal wall [2]. Conclusion With its portability, easy handiness, excellent visual information and the tube-guiding function of the introducer, the AWS may have potential to alleviate the various difficulties in intubation in emergency scenes, even in a confined space. Conclusion With its portability, easy handiness, excellent visual information and the tube-guiding function of the introducer, the AWS may have potential to alleviate the various difficulties in intubation in emergency scenes, even in a confined space. Airway equipment on the intensive care unit for management of the unanticipated difficult intubation Results Forty-five of 51 units responded (88%). Mandatory equipment levels are shown in Figure 1. Discussion Difficult intubation is more likely on the ICU, yet only 20% of units keep sufficient equipment immediately available. The most serious omissions were the 29% of units without a rescue technique immediately available and the one-third of units not routinely employing capnography. S87 Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine Figure 1 (abstract P213) A comparison of two types of new bronchial blockers, Uniblocker™ and Coopdech endotracheal blocker tube, for one-lung ventilation during thoracoscopy 2 Results Conventional HVLP cuffs do not prevent leakage of fluid past the cuff, hence the negative slope on the graphs. The LoTrach cuff does not leak and therefore the line is horizontal (see Figure 1). The clinical study shows that both the LoTrach and Portex cuffs demonstrate a gross air leak at equal and acceptable tracheal wall pressures at 33.4 and 29.7 cmH2O, respectively (see Table 1). Table 1 (abstract P215) Number of Tracheal wall Type of tube measurements pressure (cmH2O) LoTrach (LVLP) 45 29.7 (SD = 3.7) Soft Seal (HVLP) 41 33.4 (SD = 3.1) Safety of semi-open percutaneous tracheotomy when performed in critically ill burn patients K Gerold, K Dhanjani, L Price, D Noppenberger, S Milner Johns Hopkins School of Medicine, Baltimore, MD, USA Critical Care 2007, 11(Suppl 2):P216 (doi: 10.1186/cc5376) Results One hundred and eight tracheostomies were performed in intensive care in the 2-year period. Sixty-two patients were discharged with tracheostomy in situ and were reviewed by the outreach team for a cumulative total of 710 days until decannulation. There were 383 days whereby patients with a tracheostomy in situ had been noninvasively ventilated. There were three reported critical events relating to tracheostomy and no deaths. Introduction Lung injury and generalized edema from a burn and resuscitation complicates airway management and patient care. The need for long-term ventilation and multiple surgeries warrant early tracheostomy. Percutaneous techniques are well described; however, the burned and swollen neck increases all of its recognized complications. We report a modified semi-open technique for performing percutaneous tracheotomies (PT) in acutely burned patients, which we consider safer. Conclusion More than 60% of patients who had a tracheostomy inserted are discharged from critical care with a tracheostomy in situ. With the support of the outreach team these patients were successfully managed in Level 2 and Level 1 areas. This reduced the requirement for critical care (Level 3) bed-days. There was a low rate of complications. We concluded that outreach services can facilitate early and safe discharge of tracheostomy patients from critical care. Methods We reviewed the medical records of 20 patients admitted to a regional burn center requiring tracheostomy for prolonged mechanical ventilation. The procedure took place in the OR if burn excision was planned; otherwise it was performed at the bedside. The Blue Rhino tracheostomy kit was used for all PT. Major differences from other approaches included dissecting down to the pretracheal fascia, allowing the trachea to be seen and palpated; bleeding was controlled using an electrocautery, and blood vessels were retracted from the field or ligated. The trachea was palpated as the endotracheal tube was withdrawn into the proximal trachea and a flexible bronchoscope was used only to confirm the proper placement of the guidewire. Proper placement of the tracheal tube was confirmed by capnography. In patients with a deep trachea due to severe neck swelling, a proximal-long tracheostomy tube was substituted for the standard one. In the event that the airway or ventilation became compromised, this technique could be converted rapidly to an open procedure. P218 Prevention of airway control loss during percutaneous tracheostomy References References 1. Young PJ, Pakeerathan S, Blunt MC, Subramanya S: A low- volume, low-pressure tracheal tube cuff reduces pul- monary aspiration. Crit Care Med 2006, 34:632-639. 2. Young PJ, Young WH: Inflation of a pressure-limited cuff inside a model trachea. Med Eng Phys 2003, 25:465-473. 1. Young PJ, Pakeerathan S, Blunt MC, Subramanya S: A low- volume, low-pressure tracheal tube cuff reduces pul- monary aspiration. Crit Care Med 2006, 34:632-639. Methods A retrospective analysis of the ICU database was undertaken to identify all patients who had a tracheostomy (percutaneous or surgical) inserted in the ICU, and a chart review of patients discharged from the ICU with a tracheostomy in situ was performed. The following variables were collected: patient demographics; diagnosis; number of days of tracheostomy in situ; number of days on noninvasive ventilation (CPAP); and tracheos- tomy-related complications. A review of the risk management database was performed to identify any tracheostomy-related reported adverse events. Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 References 1. Young PJ, Pakeerathan S, Blunt MC, Subramanya S: A low- volume, low-pressure tracheal tube cuff reduces pul- monary aspiration. Crit Care Med 2006, 34:632-639. 2. Young PJ, Young WH: Inflation of a pressure-limited cuff inside a model trachea. Med Eng Phys 2003, 25:465-473. P216 Safety of semi-open percutaneous tracheotomy when performed in critically ill burn patients K Gerold, K Dhanjani, L Price, D Noppenberger, S Milner Johns Hopkins School of Medicine, Baltimore, MD, USA Critical Care 2007, 11(Suppl 2):P216 (doi: 10.1186/cc5376) Figure 1 (abstract P215) Figure 1 (abstract P215) performed within an average of 10 days from admission (range 0–32 days). Overall mortality in the tracheostomy group was 35%. There were no short-term complications associated with this method. Conclusion PT can be performed safely in severely burned patients using a semi-open percutaneous technique. Exposing the trachea and palpating the trachea avoids the risk of losing the airway and permits immediate access to the trachea in the event of an untoward loss of the airway. We believe that this method is safer than the more commonly used technique requiring bronchoscopic visualization. Outreach-led tracheostomy service in a cardiothoracic centre: early and safe facilitated discharge from critical care Outreach-led tracheostomy service in a cardiothoracic centre: early and safe facilitated discharge from critical care P Wilton, J Mitchell, T Apps, R Subramanian Harefield Hospital, London, UK Critical Care 2007, 11(Suppl 2):P217 (doi: 10.1186/cc5377) P Wilton, J Mitchell, T Apps, R Subramanian P Wilton, J Mitchell, T Apps, R Subramanian Harefield Hospital, London, UK Critical Care 2007, 11(Suppl 2):P217 (doi: 10.1186/cc5377) p , , al Care 2007, 11(Suppl 2):P217 (doi: 10.1186/cc5377) Introduction A retrospective analysis of a year cohort of tracheos- tomies discharged from intensive care in a specialist cardio- thoracic centre was undertaken to analyse whether facilitated outreach-led discharge was safe. Table 1 (abstract P215) Table 1 (abstract P215) Results The number of unsuccessful placement attempts was none in the UBBR group (0/10) and one in the CBBR group (1/10), two in the UBBL group (2/10) and five in the CBBL group (5/10). A fiberoptic aided technique should be more appropriate for the left- sided blocker in both groups. There was no statistical difference in bronchial blocker malpositions, the lung to collapse and the number of complications among the two groups. Furthermore, for elective thoracic surgical cases, once the lung was isolated, the management seemed to be similar for both groups. Discussion This study demonstrates that the wire-guided bronchial blocker (Uniblocker™) provides a high torque control and can be easily manipulated into the desired site of the lungs. In conclusion, our study shows that the Uniblocker™ is more useful than the Coopdech bronchial blocker tube. Results The number of unsuccessful placement attempts was none in the UBBR group (0/10) and one in the CBBR group (1/10), two in the UBBL group (2/10) and five in the CBBL group (5/10). A fiberoptic aided technique should be more appropriate for the left- sided blocker in both groups. There was no statistical difference in bronchial blocker malpositions, the lung to collapse and the number of complications among the two groups. Furthermore, for elective thoracic surgical cases, once the lung was isolated, the management seemed to be similar for both groups. Conclusions In the benchtop model, the LoTrach LVLP cuff demonstrates an acceptable wall pressure of 30 cmH2O (at an intracuff pressure of 80 cmH2O), while achieving the prevention of leakage of fluid past the cuff. The clinical study demonstrates that the tracheal wall pressure was both acceptable and equal for both the Portex HVLP and the LoTrach LVLP cuffs. The LoTrach prevents micro-aspiration in the benchtop model with acceptable tracheal wall pressures in both the benchtop and clinical studies. Discussion This study demonstrates that the wire-guided bronchial blocker (Uniblocker™) provides a high torque control and can be easily manipulated into the desired site of the lungs. In conclusion, our study shows that the Uniblocker™ is more useful than the Coopdech bronchial blocker tube. S88 Available online http://ccforum.com/supplements/11/S2 Prevention of airway control loss during percutaneous tracheostomy A Pirogov1, M Croitoru2, R Badaev3, N Davidova1, S Krimerman2, E Altman4 1Ural Academy of Medicine, Ekaterinburg, Russian Federation; 2Bnai Zion Medical Center, Haifa, Israel; 3Crmel Hospital, Haifa, Israel; 4Western Galilee Hospital, Naharyia, Israel Critical Care 2007, 11(Suppl 2):P218 (doi: 10.1186/cc5378) Background Loss of airway control during percutaneous tracheostomy (PCT) is one of the serious complications. It may happen due to an unstable position of the endotracheal tube (ETT) with its tip in the larynx and cuff above the vocal cords. This Results Of 350 patients admitted to the burn center from July 2005 to December 2006, 20 (6%) required a tracheostomy. Eighteen were performed percutaneously, 13 at the bedside. The total burn surface area averaged 46% (range 2–95%). PT were S89 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Table 1 (abstract P219) New problem seen Number (%) on CXR (n (%)) Two CXRs reviewed Uncomplicated PDT 167 (57) 15 (5) Complicated PDT 69 (24) 10 (3) One CXR reviewed Uncomplicated PDT 36 (12) 0 Complicated PDT 8 (3) 0 Total 280 25 position of the ETT is the main request for PCT performance. We retrospectively reviewed our experience with additional use of the fiberoptic bronchoscope (FOB) and tube exchanger (TE) for stabilization of ETT during PCT. Patients and methods From the 160 adult critically ill patients that underwent PCT by the Griggs technique between January 2000 and August 2001, we selected 33 patients receiving anesthesia from the same anesthetist. From this group 12 patients were ventilated through ETT by the standard technique: in 11 patients a pediatric FOB was used to control and stabilize the position of ETT during PCT, and in the remaining 10 patients a 15-Fr TE was used with the same aim instead of a pediatric FOB. The optimal diameters of FOB and TE suitable for ETT (7.5 mm, 8 mm) were found in our previous experiments, using a mechanical lung simulator. Results Loss of airway control during PCT occurred in three patients, where ventilation through the ETT was performed by the standard technique. This complication was corrected by expeditious actions of the anesthetist and surgeon. Routine chest radiography following percutaneous dilatational tracheostomy Routine chest radiography following percutaneous dilatational tracheostomy F Paladino, G Guiotto, F Lanni, F Longo, E Ruggiero, F Schirald Hospital Sao Paulo, Napoli, Italy Critical Care 2007, 11(Suppl 2):P220 (doi: 10.1186/cc5380) M Vijaya Kumar, M Huges, E Hill, G Dempsey University Hospital Aintree, Liverpool, UK M Vijaya Kumar, M Huges, E Hill, G Dempsey M Vijaya Kumar, M Huges, E Hill, G Dempsey University Hospital Aintree, Liverpool, UK Critical Care 2007, 11(Suppl 2):P219 (doi: 10.1186/cc5379) Objective To evaluate the efficacy of early electric cardioversion (EC) with a biphasic defibrillator and the impact on atrial function in recent-onset atrial fibrillation (AF). Critical Care 2007, 11(Suppl 2):P219 (doi: 10.1186/cc5 Background and objective The role of routine chest radiography (CXR) following percutaneous dilatational tracheostomy (PDT) has recently been questioned [1]. Methods The study population consisted of 21 consecutive patients (mean age 58 years; range 35–76 years) with AF lasting from less than 48 hours. Hemodynamically stable AF was treated via DC shock if sinus rhythm (SR) was not restored in 6 hours after i.v. antiarrhythmic drug therapy. All patients were pretreated with heparin 5,000 U i.v. The defibrillator used was the Heartstart MRX using a biphasic waveform and low energy (70–120 J). A trans- thoracic echo was performed pre-EC and 1 hour post-EC. All patients were sedated with midazolam (in vivo titolation). Atrial function (ejection fraction, surface area, A wave) and ventricular function (ejection fraction) were evaluated. The patients returned to the emergency department after 7 days for follow-up. Data were analyzed using descriptive statistics (Table 1). Materials and methods We performed a prospective observational study, on a mixed medical–surgical critical care unit, in 291 patients undergoing PDT under bronchoscopic guidance to assess the utility of routine postoperative CXR. Data were collected on all patients undergoing PDT from 1 November 2003 to 5 December 2006. Two postprocedure CXRs were reviewed and compared with those taken prior to PDT. Significant findings were barotraumas (pneumothorax, pneumomediastinum) and consolidation not noted on the preprocedure film. Postprocedural films reviewed were those taken immediately after PDT and, to exclude the possibility of overlooking evidence of minor barotrauma, one further film taken between 24 and 96 hours. Results DC shock was successful for all patients (100%) and in 19/21(90.4%) at first shock. There was a significant increase in atrial function with the reappearance of the A wave. There were no Results A total of 291 patients underwent PDT. Biphasic DC shock as a first-line therapy in recent-onset stable atrial fibrillation in the emergency department Biphasic DC shock as a first-line therapy in recent-onset stable atrial fibrillation in the emergency department Prevention of airway control loss during percutaneous tracheostomy In the other patients, additional use of a pediatric FOB or TE has created secure and proper position of the ETT and PCT passed smoothly without complications. Moreover, we could not register a negative influence of a pediatric FOB and 15-Fr TE presence in the ETT on ventilation parameters during PCT performance. Conclusions Routine CXR following uncomplicated PDT performed under bronchoscopic guidance appears unwarranted. Review of later films failed to reveal new abnormalities. The role of CXR following PDT appears to be restricted to those patients undergoing complicated procedures. This will lead to reductions in both medical costs [2] and exposure to ionising radiation. References 1. Datta D, Onyirimba F, McNamee MJ: Chest 2003, 123:1603- 1606. 2. Tarnoff M, Moncure M, Jones F, et al.: Chest 1998, 113:1647- 1649. 1. Datta D, Onyirimba F, McNamee MJ: Chest 2003, 123:1603- 1606. Conclusions Stabilization of the ETT position and prevention of airway control loss during PCT performance can be reached by use of a pediatric FOB or by 15-Fr TE with the same reliable results. Employment of a pediatric FOB is more expensive than a TE. 2. Tarnoff M, Moncure M, Jones F, et al.: Chest 1998, 113:1647- 1649. Routine chest radiography following percutaneous dilatational tracheostomy Two hundred and six (71%) were uncomplicated. Complications were recorded in 85 (29%) patients. Of these, 71 (24%) were minor procedural complications (multiple attempts at needle insertion (>2), minor bleeding, tracheal ring fracture) and there were 14 (5%) major complications (malplacement, major bleeding). Two hundred and thirty-six (81%) patients had two postprocedural CXRs reviewed. Of the remainder, 44 (15%) patients had at least one CXR reviewed after PDT and in 11 (4%) patients neither the report nor the CXR could be reviewed. New abnormalities were noted on 25 (9.0%) postprocedure CXRs. No new pneumothoraces were seen (Table 1). In 11 (4%) patients, neither the report nor the CXR could be reviewed. Table 1 (abstract P220) Pre-EC Post-EC Number of patients 21 Age average 59 Sinusal rhythm restoration 21/21 Left atrial ejection fraction two chambers 30 35 (P = 0.02) Left atrial ejection fraction four chambers 29 35 (P = 0.02) Left ventricular ejection fraction 52 54 (P = NS) A wave (m/s) 0.54 S90 Available online http://ccforum.com/supplements/11/S2 thromboembolic complications. After 7 days, results showed that 19/21 (90.4%) patients were in SR. P223 The ADHERE classification and regression tree model overestimates mortality rates in clinical trials: results from REVIVE I & II R Thakkar1, J Teerlink2, W Colucci3, J Young4, B Massie2 1Abbott, Abbott Park, IL, USA; 2SFVAMC/University of California – San Francisco, CA, USA; 3Boston University, Boston, MA, USA; 4Cleveland Clinic, Cleveland, OH, USA Critical Care 2007, 11(Suppl 2):P223 (doi: 10.1186/cc5383) The ADHERE classification and regression tree model overestimates mortality rates in clinical trials: results from REVIVE I & II R Thakkar1, J Teerlink2, W Colucci3, J Young4, B Massie2 1Abbott, Abbott Park, IL, USA; 2SFVAMC/University of California – San Francisco, CA, USA; 3Boston University, Boston, MA, USA; 4Cleveland Clinic, Cleveland, OH, USA Critical Care 2007, 11(Suppl 2):P223 (doi: 10.1186/cc5383) Troponin T was determined in 13 patients and found to be elevated in 10 patients (34.5% of AF patients). Transthoracic echocardiography was performed on 10 patients with persistent AF (34.5%). Seven patients had valve pathology whereas left ventricular dysfunction was present in five patients. Only one echocardiography was reported normal. Patients were treated according to local guidelines with amiodarone (19 (65.5%)), digoxin (5 (17.2%)) and β-blockers (4 (13.8%)), and DC cardio- version was used in only one patient. Eighteen (62.1%) patients were successfully cardioverted. Background Blood urea nitrogen (BUN), systolic blood pressure (SBP), and serum creatinine (Cr) were significant predictors of inhospital mortality by classification and regression tree (CART) analysis of ADHERE. REVIVE I & II (REVIVE) compared levosimen- dan with placebo, in addition to standard-of-care (SOC), in patients with acute decompensated heart failure. We hypothesized that mortality in REVIVE would be similar to ADHERE in all CART- defined risk subgroups. Conclusion Apart from known risk factors for AF such as increased age, hypertension or ischaemic heart disease, sepsis and inotropes increase susceptibility for AF. Less frequently associated causes such as congenital heart disease, obesity and diabetes can contribute towards AF. Echocardiography could reveal less obvious causes of AF like valvular pathologies and left ventricular dysfunction, and could be a useful diagnostic tool in critically ill patients with AF. Methods REVIVE (n = 700) mortality data were mapped using the same variables/cut-points as the ADHERE CART analysis. Methods REVIVE (n = 700) mortality data were mapped using the same variables/cut-points as the ADHERE CART analysis. P222 The calcium sensitizer levosimendan reduces the brain natriuretic peptide levels as compared with dobutamine in intensive care unit septic patients with decompensated heart failure Conclusion Early electric cardioversion in the emergency department setting is a simple technique that allows the restoration of SR without complications. The biphasic waveform uses lower energy with a positive impact on atrial function. Higher energy can cause transient tissue damage due to electroporation that can affect the outcome of defibrillation therapy being both pro- arrhythmic and anti-arrhythmic. The recovery of atrial function is also due to the short duration of arrhythmia. The early cardioversion avoids atrial remodelling and allows a longer duration of SR. H Michalopoulou, P Stamatis, A Bakhal, T Kelgiorgis, A Foundouli, A Basile, J Vaitsis, E Reinou, P Batika, D Pragastis Metaxa Hospital, Athens, Greece Critical Care 2007, 11(Suppl 2):P222 (doi: 10.1186/cc5382) H Michalopoulou, P Stamatis, A Bakhal, T Kelgiorgis Introduction The brain natriuretic peptide (BNP) is a useful index to follow-up patients with heart failure as well as a special diagnostic and prognostic tool. This study aims at investigating the impact of levosimendan in comparison with dobutamine on the BNP levels in ICU patients with decompensated heart failure related to septic shock. The role of levosimendan in septic patients is still under consideration. P221 Incidence and diagnosis of patients developing atrial fibrillation in intensive care Methods Twenty-nine patients (20 males and nine females) of a 70.5 ± 9.2 average age rate with persisting left ventricular dysfunction related to severe sepsis, after receiving a 48-hour conventional treatment including inotropic agents, were randomised to either 24-hour i.v. levosimendan (0.2 γ/kg/min) (n = 15) (Group A) or dobutamine (5 γ/kg/min) (n = 14) (Group B) therapy. Serial BNP measurements were performed before, at 48 hours and 5 days later. R Shankar1, I Welters2 1Burton Hospitals NHS, Burton-on-Trent, UK; 2Academic Unit of Critical Care Medicine, Liverpool, UK Critical Care 2007, 11(Suppl 2):P221 (doi: 10.1186/cc5381) Introduction Atrial fibrillation (AF) is a common arrhythmia encountered in critically ill patients. In this study we evaluated the incidence and risk factors associated with the occurrence of AF in a general ICU. Results Levosimendan therapy significantly reduced the BNP levels both in 48 hours and in 5 days as compared with dobutamine. Group A: 1,138 ± 93.7, 740.2 ± 106, 445 ± 118.3 and Group B: 1,561 ± 370.2, 1,436 ± 368, 1,850 ± 520.5, before, 48 hours and 5 days later, respectively. P = 0.025 for 48 hours and P = 0.037 for 5 days. Methods One hundred and ten patients admitted to the ICU during a 3-month period were screened for AF. Case notes and daily management charts of these patients were analysed retrospectively. Results Twenty-nine (26.3%) out of 110 patients developed AF. The mean age of patients was 71.8 (±9.2) years and the APACHE II score was 21.3 (±6.3). Electrolytes were within the normal range in 85% of the patients. The main cardiac factors identified in our patients with AF were hypertension (71.4%) and coronary artery disease (48.3%). Less commonly encountered cardiac diagnoses were congenital heart disease and history of previous atrial fibrillation. Inotropic support and sepsis were the leading noncardiac factors found in 24 (82.8%) and 22 (75.9%) patients, respectively. Diabetes mellitus and obesity contributed in 17.2% of patients. Conclusion Levosimendan therapy reduces BNP levels, reflecting a beneficial haemodynamic effect on the ICU patient with septic myocardial depression. Levosimendan in patients with acute cardiogenic shock, not responders to conventional therapy Levosimendan in patients with acute cardiogenic shock, not responders to conventional therapy L Vetrugno, F Bassi, F Giordano Azienda Ospedaliero-Universitaria, Udine, Italy Critical Care 2007, 11(Suppl 2):P224 (doi: 10.1186/cc5384) Introduction Levosimendan is a new, effective inodilator agent, which is a new alternate drug beside conventional inotropic drugs in treatment of acute and chronic heart failure. Positive inotropic effects of levosimendan is based on myocardial Ca-sensitising. Few clinical data are available about the occurrence of proarrhythmic effects of levosimendan, particularly administered in parallel with catecholamines. Introduction Cardiogenic shock remains the leading cause of death in patients hospitalized for myocardial infarction, acute valvular disease and after cardiac surgery. Levosimendan (LS) is a new inodilator that has been shown to improve hemodynamic function in patients with decompensated systolic heart failure without increased myocardial oxygen consumption. The aim of this study was to evaluate the use of LS as rescue medication in patients with low ejection fraction (EF) that are not responders to conventional therapy. Methods Twelve patients with acute cardiogenic shock admitted to the ICU were enrolled. The diagnosis of cardiogenic shock was made on cardiac index (CI) measured by thermodilution catheter <2.5 l/min/m2, and baseline echocardiography with EF measured by the biplan Simpson method <30%. LS (Orion Pharma, Helsinki, Finland) at the dose of 0.1 γ/kg/min for 24 hours continuous infusion was added to standard inotropic agents (dobutamine, enoximone, epinephrine) or IABP when CI and EF seemed not to improve or when the patient’s condition worsened. Hemodynamic measurements and echocardiography data were recorded at ICU admission and when pharmacological therapy was changed at 24, 48 and 72 hours. Method From 1 January 2006 until 30 July, 41 levosimendan- treated patients’ data were processed in our retrospective study. Indication of levosimendan therapy was acute heart failure due to myocardial infarction in 23 cases and acute progression of chronic heart failure (NYHA III–IV) in 18 cases. After a 10-minute bolus levosimendan infusion was administered at rate of 0.1 µg/kg/min for 6 hours and 24 hours in each group, respectively. We investi- gated the occurrence of sustained ventricular or supraventricular arrhythmias for the first 48 hours from the beginning of infusion. Results The ratio of hypertension, diabetes, earlier myocardial infarction and ACBG were 58%, 27%, 32% and 15%, respectively, in the monitored population (13 females, 28 males; mean age: 68 years). Retrospective study of proarrhythmic effects of levosimendan during the therapy of heart failure Retrospective study of proarrhythmic effects of levosimendan during the therapy of heart failure E Zima, G Szucs, A Soltesz, D Becker, G Fulop, L Molnar, G Barczi, B Merkely Semmelweis University, Budapest, Hungary Critical Care 2007, 11(Suppl 2):P225 (doi: 10.1186/cc5385) P223 Results Compared with ADHERE, proportionately more patients in REVIVE had SBP <115 mmHg (56.4% vs 18.6%; P < 0.001) with more patients (3.0% vs 1.9%; P < 0.05) in the highest mortality risk subgroup (SBP <115 mmHg, BUN ≥43 mg/dl, and Cr ≥2.75 mg/dl). For the total population and for every CART-defined subgroup, REVIVE inhospital mortality rates were lower than those from ADHERE. See Figure 1. S91 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine Figure 1 (abstract P224) Figure 1 (abstract P223) Mortality rates from REVIVE for subgroups defined by the ADHERE classification and regression tree model. Figure 1 (abstract P224) Figure 1 (abstract P224) Figure 1 (abstract P223) Mortality rates from REVIVE for subgroups defined by the ADHERE classification and regression tree model. Figure 1 (abstract P224) Figure 1 (abstract P223) Figure 1 (abstract P223) Mortality rates from REVIVE for subgroups defined by the ADHERE classification and regression tree model. Conclusion Clinical trials (REVIVE) may enroll proportionately more patients at increased risk of mortality in comparison with the general population (ADHERE). Despite the predicted increased mortality risk, mortality rates were lower in REVIVE than in ADHERE for the total population and for every CART-defined risk subgroup. Differences in SOC or additional risk factors, such as age or other comorbid conditions, may contribute to the poorer prognosis in nontrial populations. different mechanism of action. Catecholamines increase Ca2+ availability and LS increases myocardial cell calcium sensibility. Levosimendan in myocardial depression due to severe sepsis M Malik, Y Mandourah Riyadh Millitary Hospital, Riyadh, Saudi Arabia Critical Care 2007, 11(Suppl 2):P226 (doi: 10.1186/cc5386) Objective and method To assess the secondary preventative treatment received by the elderly ACS patient. Retrospective analysis of our Myocardial Infarction National Audit Project (MINAP) database 2003–2006. Patients were divided into three age groups: <50 years, 50–75 years and >75 years old. Data were collected from hospital admission to discharge. Introduction Myocardial depression in sepsis, among other factors, is due to calcium (Ca2+) desensitization in the myofilament. So using a Ca2+ sensitizer drug may play a beneficial role in this situation. Levosimendan has a dual mechanism; it causes Ca2+ sensitization through binding to Troponin C and opening of ATP- dependent K+ channels in vascular smooth muscle. Results A total of 1,501 consecutive patients were included in the analysis, 530 patients (35.3%) were >75 years, mean age 83.6 years (±5.1). The discharge diagnosis was ST elevation myocardial infarction in 619, UA/NSTEMI in 870 and unspecified in 12 patients. The overall inpatient all-cause mortality rate was 8.06% (121/1,501). See Table 1. Methods A prospective observational case-series study extending over a period of 18 months from November 2004 to April 2006. We analyze the data of 18 patients receiving levosimendan for myocardial depression due to severe sepsis and compare them with our historical data in the previous year of the same group of patients regarding mortality. All those patients were included in the study who had a pulmonary artery catheter (PAC) and who after initial resuscitation (early goal-directed therapy (EGDT)) did not respond to treatment and their cardiac index (CI) was <2.2. Each patient than received an infusion of levosimendan at 0.1 µg/kg/min without a loading dose. Hemodynamic parameters such as the CI, mixed venous saturation (SvO2) and mean arterial pressure (MAP) were recorded at 0, 12, 24 and 48 hours. Noradrenaline was used to maintain a MAP above 65 mmHg. Patients were followed for 30 days to document the 7th-day and 30th-day mortality. SPSS 11 was used for statistical analysis. The Student t test was used as a test of significance. Table 1 (abstract P227) <50 years 50–75 years >75 years Total 149 822 530 STEMI 84 364 172 Inhospital mortality 0 33 (4%) 88 (17%) Aspirin (%) 98.7 94.5 90.4* ACE-I (%) 84.6 83.4 66.4* β-Blocker (%) 93.8 82.4 72.9* Statin (%) 96.5 95.6 89* *P < 0.001, chi-squared. P226 P226 treatment strategies and secondary prevention, despite the elderly being the fastest growing section of the population. The literature suggests the elderly do not receive appropriate therapy in this setting. What is the current UK experience? Long-term prognosis of octagenarian patients with ST-elevation acute myocardial infarction treated by primary angioplasty E Abu Assi Hospital Clínico Universitario, Santiago de Compostela, Spain Critical Care 2007, 11(Suppl 2):P228 (doi: 10.1186/cc5388) Conclusion It is evident from our study that levosimendan improves hemodynamic response in septic patients. Although it improves the mortality, we cannot say with full confidence that these improved hemodynamic parameters are responsible. Randomised control trials are needed to answer this question, which are underway. Introduction The incidence of acute myocardial infarction (AMI) in old patients is increasing due to rapid aging of the population. This is of particular concern because AMI in patients who are ≥80 years old is associated with high mortality. However, the role of reperfusion therapies is not clear in these patients. Levosimendan in myocardial depression due to severe sepsis Conclusions The elderly ACS patient forms a high-risk group. The therapeutic approach in this group should be justifiably as aggressive as that in younger patients, balancing risks with benefits. The elderly patient should be prescribed secondary preventative measures, and our data show considerably greater numbers can benefit from standard treatment than suggested by the published literature. Results The average age was 67.6 ± 10.39 years and the APACHE II score was 26.33 ± 2.37. Patients were divided into three subgroups: survivors, 7th-day and 30th-day mortality groups. There was no significant difference in these subgroups regarding age and APACHE II score. Levosimendan group 7th-day and 30th- day mortality was 33% and 66% as compared with historical data of 37% and 71%, respectively. The change in CI in the survivor group was significant (P = 0.021), from 2.11 ± 0.17 to 3.8 ± 0.28, while in the 7th-day and 30th-day mortality groups it was insignificant. SvO2 increased in the survivor and 30th-day mortality groups significantly (P = 0.011 and P = 0.035, respectively). It did not show any significant improvement in the other group. MAP also showed significant improvement in the survivor group (P = 0.026) and insignificant in others. Levosimendan in patients with acute cardiogenic shock, not responders to conventional therapy Three ventricular arrhythmias and one supraventricular arrhythmia were observed during the 48-hour period, all of them occurred in acute heart failure patients with acute myocardial infarction. Parallel usage of catecholamines (noradrenalin and/or dopamine) and levosimendan therapy was observed in three cases, in one of them ventricular tachycardia was observed 3 hours after starting levosimendan infusion. No arrhythmia was observed in chronic heart failure patients. The incidence of proarrhythmic effects during levosimendan therapy was 9.75% of the whole analysed population and was 17.4% at acute heart failure during acute myocardial infarction. Results The data collection showed: an increase in CI (baseline to standard therapy) of 2.6 ± 0.51 (P < 0.001), and standard therapy to LS of 2.93 ± 0.67 (P < 0.003) that seem to be additive. Significant increase in EF was noted in comparison with standard therapy (29.88 ± 6.15, P < 0.035) and after LS therapy (38.44 ± 6.56, P < 0.001) (Figure 1). To find differences between baseline and pharmacological therapy changes at 24, 48 and 72 hours a t test was performed. Conclusion With these results the authors would like to draw attention to the proarrhythmic effects of levosimendan during acute heart failure therapy, especially in the case of parallel usage with catecholamines. Conclusion We found an additive effect of dobutamine, enoximone and LS that theoretically can be explained by the S92 Available online http://ccforum.com/supplements/11/S2 P228 P228 Long-term prognosis of octagenarian patients with ST-elevation acute myocardial infarction treated by primary angioplasty E Abu Assi Hospital Clínico Universitario, Santiago de Compostela, Spain Critical Care 2007, 11(Suppl 2):P228 (doi: 10.1186/cc5388) Long-term prognosis of octagenarian patients with ST-elevation acute myocardial infarction treated by primary angioplasty Long-term prognosis of octagenarian patients with ST-elevation acute myocardial infarction treated by primary angioplasty Outcome in myocardial infarction is related to the morphologic pattern of ST elevation Introduction Early percutaneous coronary intervention (PCI) is the most effective treatment for acute coronary syndrome (ACS, ST- elevation myocardial infarction (STEMI), non-STEMI, unstable angina pectoris) complicated by states Killip 3 and 4. R García-Borbolla1, I Nuñez Gil2, J García Rubira2, A Fernández Ortiz2, L Perez Isla2, M Cobos2, C Macaya2 1Hospital Universitario Puerta del Mar, Cádiz, Spain; 2Hospital Clínico San Carlos, Madrid, Spain Critical Care 2007, 11(Suppl 2):P229 (doi: 10.1186/cc5389) Method A total of 1,187 patients suffering from high-risk acute coronary syndrome (hrACS) were treated in our center in 2005. States Killip 3 and 4 have developed perioperatively in 186 of these patients. International studies have proven high mortality in these patient groups – especially in state Killip 4. Our aim was to analyze the inhospital mortality of the state Killip 3 and 4 patient group treated in our center in 2005. Purpose Although invasive management of ST-segment elevation myocardial infarction (STEMI) has improved the clinical outcome, early mortality remains an important issue. Our purpose is to assess the utility of the initial electrocardiographic (ECG) pattern in detecting patients who are at increased risk despite the current recommendations of revascularization. Results Seven hundred and two patients with STEMI and 485 patients with hrACS were admitted to our center in 2005. The mortality of these patients was 4.84% (STEMI) and 3.71% (hrACS), and the main cause of this mortality (37.7%) was the Killip 3/4 state, which was observed in 11.9% of the STEMI patients and in 17.9% of hrACS patients (n = 84 and 87). The mean age of the Killip 3/4 patients was 70 ± 10 years. Angio- logically successful PCI was performed in 97.9% of the cases. The ratio of revascularized coronaries was left anterior descending coronary artery (LAD): 66 (35.9%), right coronary artery (RCA): 33 (17.9%), circumflex coronary artery (CX): 28 (15.2%), PCI in left main coronary artery: 28 (12.5%), LAD + CX: 15 (8.15%), RCA + LAD: 7 (3.8%), CX + RCA: 6 (3.26%), venous bypass graft: 2 (1.1%). No PCI was performed in two cases. Adjuvant therapies of intraaortic balloon counterpulsation in 67 (36%), mechanical ventilation in 62 (33.3%), continuous veno-venous hemofiltration in 12 (6.45%), and levosimendan therapy in 86 (46.2%) patients were used. Ten (5.4%) of the patients had advanced adult life support (cardiopulmonary resuscitation) (AALS) before arrival at our center, and AALS was performed in the perioperative period in 16 (8.6%) patients. P227 Objective To evaluate the mid-term and long-term prognosis of octogenarian patients with ST-elevation myocardial infarction (STEMI) treated with primary coronary angioplasty (PCA). The elderly acute coronary syndrome patient: a neglected population? A Turley1, A Roberts1, A McDermott2, P Adams2 1The James Cook University Hospital, Middlesbrough, UK; 2Royal Victoria Infirmary, Newcastle upon Tyne, UK Critical Care 2007, 11(Suppl 2):P227 (doi: 10.1186/cc5387) Methods We studied retrospectively, from January 2000 to March 2005, 73 patients ≥80 years with STEMI treated with PCA. At the end of follow-up, we assessed the incidence of death, myocardial infarction and necessity of new procedures of revascularization of the treated vessel. Introduction Cardiovascular disease is the commonest cause of death in the elderly (>75 years). The elderly acute coronary syndrome (ACS) patient forms a particular high-risk cohort. Clinical trials traditionally concentrate on younger patients for both ACS Results The average age was 84 ± 3.6 years, 39 (58%) were women. The location of the AMI was anterior in 56%, and 25% were diabetic. The average follow-up time was 19 ± 17 months. During the follow-up, 43 patients developed events, most of them S93 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine Figure 1 (abstract P228) Figure 1 (abstract P229) Figure 1 (abstract P229) Figure 1 (abstract P228) pattern of group 1 remained significantly related to mortality (P = 0.013) together with the number of leads with STE. Conclusion The initial STE pattern is useful in detecting patients at higher risk of death or cardiogenic shock, despite the adequate revascularization therapy in STEMI. (n = 28) consisting of death (23 by cardiac death). However, most of these events occurred in the first month after the admission, the mortality between 1 month and 3 years being low (Figure 1). Percutaneous coronary intervention in acute coronary syndrome complicated by states Killip 3 and 4 in 2005 Percutaneous coronary intervention in acute coronary syndrome complicated by states Killip 3 and 4 in 2005 E Zima, G Szabo, D Becker, G Fulop, L Geller, L Molnar, G Barczi, S Toth, A Horvath, A Apor, B Merkely Semmelweis University, Budapest, Hungary Critical Care 2007, 11(Suppl 2):P230 (doi: 10.1186/cc5390) P230 Conclusion Our data show that the octogenarian patients with STEMI treated by primary PCA developed a very high mortality. However, this mortality especially concentrates in the first month after the procedure, being low between 1 month and 3 years. Abstract withdrawn Abstract withdrawn Outcome in myocardial infarction is related to the morphologic pattern of ST elevation The early inhospital mortality of hrACS aggravated by state Killip 3/4 was 10.7% (20 patients) – according to subgroup: Killip 3: 0.06%; Killip 4: 30.5%. Methods We analyzed 446 consecutive patients (age 61.9 ± 13.8 years, 76.5% male) admitted in the first 12 hours of STEMI to our coronary unit. Exclusion criteria were left bundle branch block at admission or previous myocardial infarction. Most patients (87%) were treated with primary angioplasty. Patients treated with thrombolytics and with early reperfusion criteria were programmed to coronary angiography the following day. Two groups were defined according to the presence of ST-segment elevation (STE) together with distortion of the terminal portion of the QRS in two or more adjacent leads (group 1) or the absence of this pattern (group 2) (Figure 1). Results There were 102 (22.8%) patients in group 1 and 344 (77.2%) in group 2. No differences in age or risk factors were seen between both groups. The number of diseased vessels was similar. Group 1 had higher CK, MB-CK and cardiac troponin I. The maximal Killip class was >2 during hospitalisation in 38% of group 1 vs 24% (P = 0.009). Group 1 had more mortality (8.8% vs 2.6%, P = 0.005) and more cardiogenic shock. Other ECG character- istics related to mortality were the sum of STE in all leads, the number of leads with STE and ST segment depression. After a logistic regression analysis including all ECG characteristics, the S94 Available online http://ccforum.com/supplements/11/S2 Figure 1 (abstract P233) Figure 1 (abstract P233) Conclusion The prognosis of state Killip 3/4 and successive multiorgan failure as the high-mortality complication of hrACS can be improved by early successful PCI, and the concomitant pharmacologic and nonpharmacologic supportive therapy. Figure 1 (abstract P233) P232 Table 1 (abstract P232) <2 2–4 4–6 >6 Symptom to balloon time hours hours hours hours P value ST-segment resolution (%) 95 92 86 78 0.0001 Procedural success (%) 97 95 91 84 0.03 Mortality (%) 6 9 12 29 <0.001 Conclusion ST elevation with distortion of the terminal portion of QRS predicts impaired CC. Early recognition of this pattern should warrant prompt treatment. P234 Hemoglobin concentration on admission influences the rate of inhospital 30-day mortality and complications in patients with acute myocardial infarction: a retrospective analysis of 660 Chinese patients Conclusion This study shows that, in patients with STEMI treated by PCA, SBT is related to ST-segment resolution, to PS and to mortality Y Zhao, W Gao, H Wu, J Li Institute of Geriatric Cardiology, Beijing, China Critical Care 2007, 11(Suppl 2):P234 (doi: 10.1186/cc5394) P232 Symptom onset to balloon time in patients with ST- segment elevation myocardial infarction treated by primary coronary angioplasty: influence on ST-segment resolution and on mortality therapeutic and prognostic implications. Our purpose was to correlate the electrocardiogram (ECG) pattern and CC in STEMI. Methods We analyzed ECG and angiographic CC in 242 consecutive patients (62 ± 14 years, 79% male) with STEMI treated with primary angioplasty. Patients were divided into two groups based on the magnitude of ST elevation with/without distortion of the terminal portion of the QRS (group 1/group 2). The degree of collateral filling (Rentrop) was assessed as grade 0 = none, grade 1 = filling of side branches of the occluded artery, grade 2 = partial epicardial filling, and grade 3 = complete epicardial filling of the occluded artery. therapeutic and prognostic implications. Our purpose was to correlate the electrocardiogram (ECG) pattern and CC in STEMI. M th d W l d ECG d i hi CC i 2 2 Introduction With controversy in the field, we wanted to assess the influence of symptom onset to balloon time in ST-segment elevation myocardial infarction (STEMI) treated by primary coronary angioplasty (PCA), on ST-segment resolution and on the 1-year mortality. Introduction With controversy in the field, we wanted to assess the influence of symptom onset to balloon time in ST-segment elevation myocardial infarction (STEMI) treated by primary coronary angioplasty (PCA), on ST-segment resolution and on the 1-year mortality. Methods Retrospectively (January 1998–August 2004), we studied 558 consecutive patients with STEMI treated by PCA. The symptom to balloon time (SBT) was defined as the elapsed time between symptom onset and the first balloon inflation, and the procedural success (PS) as the TIMI III flow post-PCA with estenosis <50%. Results ST elevation with distortion of the terminal portion of QRS were present at initial ECG in 55 patients (23%). This group had a lower incidence of Rentrop grade 2/3 than group 2 (P = 0.006, Figure 1). Moreover, group 1 had higher enzyme release, worse maximal Killip class and more frequently the combined variable death/shock. Group 1 more often had proximal occlusion of the infarction-related artery and nonreflow. Multivariate analysis found ECG to be an independent predictor of outcome. Results Table 1 summarises clinical features according to SBT. After adjustment of potentially confounding variables, SBT was the variable associated with less ST-segment resolution (HR 1.772, 95% CI 1.46–4.15, P = 0.02). P233 Conclusion It is demonstrated in this study that a reve relationship between baseline hemoglobin values adverse cardiovascular events is observed in patient myocardial infarction. There is a greater incidence of a hemoglobin concentration on admission in the elder than that in the younger one. P235 Anaemia at the moment of admittance is associ higher heart failure and mortality among patient acute coronary syndrome J Garcia Acuña, A López Lago, E González Babarro B Cid Alvarez, E Abu Assi, M Jaquet Herter, A Amar M Santás Alvarez, S De Lange, J González Juanatey Clinic Universitary Hospital of Santiago, Santiago de C Spain Critical Care 2007, 11(Suppl 2):P235 (doi: 10.1186/c Background The search for novel and modifiable ri d (ACS) Results Patients with hemoglobin values between 140 and 159 g/l were used as the reference; cardiovascular mortality increased as hemoglobin levels fell below 140 g/l or rose ≥160 g/l. The in- hospital 30-day mortality was 25.0% in patients with hemoglobin concentrations <100 g/l, 20.4% in patients with hemoglobin concentrations of 100–119 g/l, 10.6% in patients with hemoglobin concentrations of 120–139 g/l, 4.3% in patients with hemoglobin concentrations of 140–159 g/l, and 8.5% in patients with hemo- globin concentrations of 160 g/l or greater. The increase in risk of complications associated with a low hemoglobin concentration was more pronounced in patients with anemia than in patients without. Compared with patients with hemoglobin concentrations of 140–159 g/l, those with hemoglobin concentrations <140 g/l had more inhospital complications and those with hemoglobin concentrations ≥160 g/l also had more arrhythmia and pneumonia (P < 0.001, respectively). As expected, a significant inverse corre- lation between hemoglobin concentrations and ages (r = –0.51; P < 0.001) was observed, and a significant positive correlation between hemoglobin concentrations and albumin concentrations and in the patients with acute myocardial infarction. worse intrahospital prognosis: major incidence of cardiac insufficiency (42% to 20%, P = 0.0001), refractory angina pectoris (14% to 6%, P = 0.01), more electric complications (12% to 9%, P = 0.01) and a higher mortality (14% to 7%, P = 0.009). The presence of anaemia was an independent predictor of cardiac insufficiency and death at the moment of admittance to the CCU (OR = 2.20, 95% CI = 1.10–4.35; P = 0.002) Conclusion The presence of anaemia is a powerful predictor of a worse prognosis in patients with ACS. Long-term prognostic impact of anemia in patients with ST-elevation acute myocardial infarction treated by primary coronary angioplasty E Abu Assi, F Soto, R Vidal, E Pardes, A Amaro Hospital Clínico Universitario, Santiago de Compostela, Spain Critical Care 2007, 11(Suppl 2):P236 (doi: 10.1186/cc5396) Conclusion It is demonstrated in this study that a reverse J-shaped relationship between baseline hemoglobin values and major adverse cardiovascular events is observed in patients with acute myocardial infarction. There is a greater incidence of patients with a hemoglobin concentration on admission in the elderly population than that in the younger one. Introduction Anemia has been shown to be a powerful and independent predictor of 30-day outcomes among patients presenting with acute coronary syndrome. However, there are limited and conflicting data about its long-term independent predictive value in this setting. Introduction Anemia has been shown to be a powerful and independent predictor of 30-day outcomes among patients presenting with acute coronary syndrome. However, there are limited and conflicting data about its long-term independent predictive value in this setting. Objectives To investigate the long-term prognostic impact of anemia in patients with ST-elevation acute myocardial infarction (STEMI) treated by primary coronary angioplasty (PCA). P233 Anaemia is associated with other factors of a worse prognosis such as renal dysfunction, peripheral artery disease and diabetes mellitus. P235 Anaemia at the moment of admittance is associated with higher heart failure and mortality among patients with acute coronary syndrome Methods Retrospectively, from January 2001 to December 2003, we studied 298 consecutive patients with STEMI treated with PCA. Patients were classified into two groups according to having anemia or nonanemia at admission (for men Hb < 13 vs ≥13 g/dl, and for women Hb < 12 vs ≥12 g/dl). We defined the composite endpoint as death or rehospitalization for heart failure or acute coronary event. The average follow-up time was 24 months and was determined in 97%. J Garcia Acuña, A López Lago, E González Babarro, B Cid Alvarez, E Abu Assi, M Jaquet Herter, A Amaro Cendon, M Santás Alvarez, S De Lange, J González Juanatey Clinic Universitary Hospital of Santiago, Santiago de Compostela, Spain Critical Care 2007, 11(Suppl 2):P235 (doi: 10.1186/cc5395) Results Anemia was present in 41 patients (14%). At the end of follow-up, 109 patients (37%) developed ≥1 component of the composite endpoint (52 deaths and 66 rehospitalization). The event-free survival was 62% in the group with anemia versus 82% in the other group (P < 0.001). After controlling for a variety of baseline clinical, laboratory, and angiographic variables, anemia was a strong and independent predictor of death or rehospitaliza- tion for heart failure or acute coronary event (HR 1.96, 95% CI 1.21–3.17, P = 0.006). Figure 1 shows that patients with anemia present a worse prognosis. Background The search for novel and modifiable risk factors in acute coronary syndrome (ACS) can open new strategies. We decided to evaluate the prevalence of anaemia and determine its influence on the prognosis of hospitalized ACS patients. Patients and methods Four hundred and twenty-eight consecutive patients hospitalized for ACS between 2005 and 2006 in a coronary care unit (CCU) of a cardiology department of a tertiary hospital were studied. During their hospitalization we registered cardiovascular risk factors; we determined the presence of microalbuminuria (>3 mg/dl) in a 24-hour urine sample. We also took blood samples during the first 24 hours of their admittance to the CCU for a complete haemogram, levels of total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, creatinine, creatinine clearance (Cockroft–Gault equation), glucose, HbAc1, high- sensibility C-reactive protein and a follow-up of levels of Troponin, CK and CK-MB. Figure 1 (abstract P236) P233 Coronary collateral circulation status is correlated with the initial electrocardiographic pattern in ST-elevation myocardial infarction I Nuñez Gil1, R Garcia de la Borbolla2, J Garcia Rubira1, A Fernandez Ortiz1, M Manzano Nieto1, R Hernandez Antolin1, C Macaya1 1Hospital Clínico San Carlos, Madrid, Spain; 2Hospital Universitario Puerta del Mar, Cadiz, Spain Critical Care 2007, 11(Suppl 2):P233 (doi: 10.1186/cc5393) Objective To determine the association between hemoglobin concentrations on admission and inhospital 30-day cardiac mortality and complications among patients with acute myocardial infarction during their hospital course. I Nuñez Gil1, R Garcia de la Borbolla2, J Garcia Rubira1, A Fernandez Ortiz1, M Manzano Nieto1, R Hernandez Antolin1, C Macaya1 1Hospital Clínico San Carlos, Madrid, Spain; 2Hospital Universitario Puerta del Mar, Cadiz, Spain Critical Care 2007, 11(Suppl 2):P233 (doi: 10.1186/cc5393) Methods We conducted a retrospective study of data on 660 Chinese patients who were hospitalized with acute myocardial infarction. Patients were categorized according to the hemoglobin concentration on admission, and data were evaluated to determine whether there was an association between the hemoglobin concentrations on admission and inhospital 30-day mortality and complications. Complications were defined as cardiogenic shock, congestive heart failure, arrhythmia, ventricular tachycardia or fibrillation and pneumonia. Introduction The status of coronary collateral circulation (CC) in the first hours of ST-elevation myocardial infarction (STEMI) may influence outcome. Early recognition of the CC status may have S95 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Results Patients with hemoglobin values between 140 were used as the reference; cardiovascular mortality hemoglobin levels fell below 140 g/l or rose ≥160 hospital 30-day mortality was 25.0% in patients with concentrations <100 g/l, 20.4% in patients with concentrations of 100–119 g/l, 10.6% in patients with concentrations of 120–139 g/l, 4.3% in patients with concentrations of 140–159 g/l, and 8.5% in patients globin concentrations of 160 g/l or greater. The incre complications associated with a low hemoglobin c was more pronounced in patients with anemia than without. Compared with patients with hemoglobin co of 140–159 g/l, those with hemoglobin concentratio had more inhospital complications and those with concentrations ≥160 g/l also had more arrhythmia an (P < 0.001, respectively). As expected, a significant in lation between hemoglobin concentrations and age P < 0.001) was observed, and a significant positiv between hemoglobin concentrations and albumin co and in the patients with acute myocardial infarction. P237 Cardiogenic shock in the Aachen Digital Myocardial Infarction Registry A Kersten, M Merx, H Dückers, M Kelm, W Lepper UK Aachen, Germany Critical Care 2007, 11(Suppl 2):P237 (doi: 10.1186/cc5397) Cardiogenic shock in the Aachen Digital Myocardial Infarction Registry Cardiogenic shock in the Aachen Digital Myocardial Infarction Registry Introduction Evaluation of hemodynamics in patients with acute myocardial infarction (AMI) is crucial. Hemodynamic changes during intra-aortic balloon counterpulsation (IABC) are monitored using invasive methods for assessment of hemodynamics in patients with cardiogenic shock (CS). A Kersten, M Merx, H Dückers, M Kelm, W Lepper UK Aachen, Germany Critical Care 2007, 11(Suppl 2):P237 (doi: 10.1186/cc5397) Introduction Guideline-oriented therapy of acute coronary syndrome (ACS) with ST-elevation myocardial infarction (STEMI) calls for quick and early treatment. The creation of an infarct network has been associated with streamlined treatment and a reduction of hospital mortality. Whether patients with cardiogenic shock (CS) receive similar, optimized treatment as regular STEMI patients is unclear. Objective To evaluate hemodynamic indices in patients with AMI, complicated by CS and managed with IABC during initial days of treatment. Methods Hemodynamic indices including cardiac output (CO), cardiac index (CI), mean pulmonary artery pressure (MPAP) and pulmonary capillary wedge pressure (PCWP) were measured by pulmonary artery catheterization using an intermittent thermo- dilution technique for patients with AMI complicated by CS, admitted within 12 hours from the onset of pain and managed by IABC. All measurements were performed within 48 hours after initiation of IABC. Methods We created the Aachen Digital Myocardial Infarction Registry (ADMIRE) database according to the European Cardiology Audit and Registration Data standards for clinical cardiology practice. Patients were labelled according to the presenting form of ACS. The infarct network included local ambulance services (LA), local hospitals (LH) and the interventional center with an emergency department (ED) and a 24/7 cath lab crew. To improve performance we introduced prehospital triage, fax-transmission of ECG, and direct alert of the cath lab crew by telephone. We determined treatment variables, median index-to-door (IDT) and door-to-sheath (DST) times and hospital mortality. Results Twenty-nine patients were investigated according to the study protocol: 15 (51.7%) men and 14 (48.3%) women. Average age was 71.4 ± 6.9 years. Anterior AMI was diagnosed for 19 (65.5%) patients, and inferior in 10 (34.5%) patients. P237 Primary percutaneous transluminal coronary angioplasty (PTCA) was successfully performed for 22 (75.9%) patients, primary PTCA was unsuccessful for four (13.8%) patients, and seven (24.1%) patients underwent scheduled cardiac surgery within the first 2 weeks. The inhospital mortality rate was 41.4% (12 patients). Results Between April and December 2006 we treated 593 patients including 119 STEMI (20.1%) and 45 CS patients (7.6%); 66.7% were male, mean age was 67.4 years. CS presented with ST elevation in 48.9%, as non-STEMI in 33.3%, rescue percutaneous coronary intervention (PCI) in 11.1% or with subacute ACS in 6.7%; 30.4% of CS were admitted through LA, 67.4% through LH and only one patient through the ED. Upon admission, 50% of CS had required CPR, 69.6% were on mechanical ventilation. In total 89.1% of CS underwent angiography, with revascularization in 69.8% and intra-aortal balloon pump treatment in 68.1%. The median DST for CS vs STEMI was 82 vs 59.5 minutes (P = 0.07), and the IDT was shorter for CS (172 vs 385 min, P < 0.05). Stratified by admission source, the DST was equal between LA and LH (66 vs 84 min, P = 0.75). CS patients with ST elevation were not treated significantly faster than those without or CS with rescue PCI (64 vs 84 vs 94 min, P > 0.05 for each). Prehospital CPR did not lead to significantly altered DST. The DST was <60 minutes in 31.3% of CS compared with 50% STEMI patients. Mortality in CS patients was significantly higher than that of STEMI patients (56.5% vs 7.6%, P < 0.05) but equal among CS subgroups (50% for ST- elevation CS, 80% for non-STEMI CS, 40% for rPCI CS, no deaths for CS with subacute ACS). It did not differ by admission source and was not influenced by a DST < 60 minutes, intra-aortal balloon pump or revascularization status. The initial (after initiation of IABC) CO was 3.7 ± 1.2 l/min, CI was 1.9 ± 0.7 l/min/m2, MPAP was 30 ± 7.1 mmHg (maximum 43 mmHg), PCWP was 19.1 ± 5.1 mmHg (maximum 26 mmHg). After the first 24 hours of IABC, the CO was 3.8 ± 1.6 l/min, CI was 2 ± 0.9 l/min/m2, MPAP was 23.7 ± 7.1 mmHg (maximum 36 mmHg), PCWP was 16.8 ± 4 mmHg (maximum 24 mmHg). P238 Conclusion Our data demonstrate that baseline anemia is a strong and independent predictor of future adverse events at 2 years in patients with STEMI treated with PCA. P238 Intra-aortic balloon counterpulsation: impact on patient hemodynamics in acute myocardial infarction complicated by cardiogenic shock J Brazdzionyte, A Macas, A Mickeviciene, G Baksyte Kaunas University of Medicine, Kaunas, Lithuania Critical Care 2007, 11(Suppl 2):P238 (doi: 10.1186/cc5398) P238 Intra-aortic balloon counterpulsation: impact on patient hemodynamics in acute myocardial infarction complicated by cardiogenic shock J Brazdzionyte, A Macas, A Mickeviciene, G Baksyte Kaunas University of Medicine, Kaunas, Lithuania Critical Care 2007, 11(Suppl 2):P238 (doi: 10.1186/cc5398) Intra-aortic balloon counterpulsation: impact on patient hemodynamics in acute myocardial infarction complicated by cardiogenic shock J Brazdzionyte, A Macas, A Mickeviciene, G Baksyte Kaunas University of Medicine, Kaunas, Lithuania Critical Care 2007, 11(Suppl 2):P238 (doi: 10.1186/cc5398) Figure 1 (abstract P236) Figure 1 (abstract P236) Results The prevalence of anaemia (Hb < 11 g/dl in women and Hb < 12 g/dl in men) in patients with an ACS was 15.4%. This group was characterised by the following: woman (P < 0.0001), higher age (P = 0.0001), less weight (P = 0.01), higher frequency of high blood pressure (P = 0.0001), diabetes mellitus (P = 0.0001), history of ischaemic heart disease (P = 0.002) and peripheral artery disease (P = 0.0001). This group presented a major proportion of the NSTEMI (P = 0.015), higher level of renal dysfunction (77% to 32%, P = 0.0001), and microalbuminuria (61% to 32%, P = 0.0001). Patients with anaemia presented a S96 Available online http://ccforum.com/supplements/11/S2 P239 Elevation of Troponin T in critically ill septic patients is common: but does it matter? A Thornley, A Turley, M Johnson, B Kunadian, M de Belder, J Gedney The James Cook University Hospital, Middlesbrough, UK Critical Care 2007, 11(Suppl 2):P239 (doi: 10.1186/cc5399) P237 After 48 hours of IABC, CO was 4.1 ± 1.7 l/min, CI was 2.1 ± 0.8 l/min/m2, MPAP was 23.8 ± 6.5 mmHg (maximum 44 mmHg), PCWP was 16.8 ± 4.6 mmHg (maximum 24 mmHg). Conclusion Intra-aortic balloon counterpulsation has a positive impact on hemodynamic changes of patients with acute myocardial infarction complicated by cardiogenic shock during the initial days of treatment. Elevation of Troponin T in critically ill septic patients is common: but does it matter? A Thornley, A Turley, M Johnson, B Kunadian, M de Belder, J Gedney The James Cook University Hospital, Middlesbrough, UK Critical Care 2007, 11(Suppl 2):P239 (doi: 10.1186/cc5399) Background Troponin T (TnT) is an established marker of adverse outcome in acute coronary syndrome patients and aids risk stratification. Myocardial dysfunction and elevated of TnT are common in critically ill patients and cardiology advice is often sought. Conclusion Despite their higher complexity, patients with CS were treated as fast as patients with STEMI, yet there was room for improvement to increase the number of patients treated within the first hour of admission for both STEMI and CS. Structural changes and further implementation of standard operating procedures might achieve this. We could not show a mortality difference for any of our treatment variables, which might be due to the low number of patients. Objective To evaluate the role of TnT as a predictor of all-cause mortality in patients with severe sepsis/septic shock as defined by international criteria. S97 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin (odds ratio 1.29 for 1,000 units) and no administration of inotropic drug on day 1 (odds ratio 34.5) decrease the probability of inhospital complications. The average efficacy of prognostication reached 96.5%; the presence of complications was correctly predicted in 88.9% of cases, and the absence of complications in 100% of cases. Methods A prospective observational study was performed on patients admitted to a general adult ICU within 24 hours of the development of severe sepsis/septic shock. Serial TnT samples were taken over the first 96 hours. Patients were grouped into three groups: A, TnT < 0.01 ng/ml; B, TnT 0.01–0.099 ng/ml; and C, TnT > 0.099 ng/ml. Conclusion The HRV parameter LF on day 3, and LV ESV, atrial fibrillation/flutter and inotropic agent administration on day 1 are statistically significant independent predictors of inhospital complications of MI with an average predictive efficacy of 96.5%. Results Blood from 49 patients was analysed. The peak Troponin level was elevated (>0.01 ng/ml) in 39/49 patients (80%). There was no significant difference between the three groups in terms of hypertension, history of angina, myocardial infarction or systolic blood pressure at time of ICU admission. Table 1 (abstract P239) Introduction The aim of this study was to investigate the relationship between blood pressure and plasma magnesium levels in patients referred to the emergency department with hypertensive attack. Epidemiological evidence on the effects of magnesium on blood pressure is inconsistent. Metabolic and experimental studies suggest that magnesium may have a role in the regulation of blood pressure. Magnesium regulates various ion channels in many tissues, including those of the cardiovascular system. Magnesium is the second most abundant intracellular cation, and the important element that has numerous biological functions in the cardio- vascular system. Furthermore, magnesium acts as a calcium antagonist, regulating the calcium metabolism. Conclusions Elevated biochemical markers of cardiac myocyte damage are common in patients with severe sepsis/septic shock. TnT elevation is a predictor of 6-month all-cause mortality. Clinicians should be aware of the significance of an elevated TnT assay in this patient population. Prognostic markers in the acute phase of myocardial infarction G Baksyte1, A Macas1, J Brazdzionyte1, V Saferis1, M Tamosiunas2, A Krisciukaitis1 1Kaunas University of Medicine, Kaunas, Lithuania; 2Institute for Biomedical Research, Kaunas, Lithuania Critical Care 2007, 11(Suppl 2):P240 (doi: 10.1186/cc5400) Results Seventy-three patients (35 of whom were female, 38 males) were included in the study. The average age was 47 ± 6.3 (ranging from 33 to 68 years). The average blood pressure of the patients was found as systolic 200 ± 10 (range 185–240) mmHg, diastolic 105 ± 7 (range 95–110) mmHg. The average plasma magnesium levels were 1.4 ± 0.3 (range 0.9–2.2) mg/l. The plasma magnesium levels were low in 29 patients (ranging from 0.9 to 1.7 mg/l). There was a negative relationship systolic blood pressure and plasma magnesium level (P < 0.05). In addition, there was a negative relationship diastolic blood pressure and plasma magnesium level (P < 0.05). Introduction The aim of the study was to assess the prognostic value of heart rate variability, arrhythmias and left ventricular systolic and diastolic function for the course and the outcome of myocardial infarction (MI). Methods We prospectively studied 57 consecutive patients admitted to the ICU of the Department of Cardiology of Kaunas Medical University Hospital between 2002 and 2004 with acute MI. The study protocol included 24-hour ECG monitoring on the first day and the third day of admission and echocardiography performed at days 2–4. Inhospital prognostic endpoints were death and nonfatal events: postinfarction angina, progressive heart failure, pulmonary edema and cardiogenic shock. Heart rate variability (HRV) was assessed at days 1 and 3 by a 24-hour recording using the ‘HeartLab’ system. A logistic regression model was used to select the combination of statistically significant variables and predict the complications. Conclusion Low plasma magnesium levels would be an important factor for elevated blood pressure and hypertensive attack. Elevation of Troponin T in critically ill septic patients is common: but does it matter? Patients with undetectable TnT levels (<0.01 g/ml) had significantly lower 6- month mortality rates than those with detectable levels (group A 2/10 (20%) vs Group B/C 23/39 (59%), P = 0.037; group B 8/15 (53%), group C 15/24 (63%)). See Table 1. The relationship between blood pressure and plasma magnesium level in hypertensive patients The relationship between blood pressure and plasma magnesium level in hypertensive patients A Bayir, B Cander, A Ak, S Girisgin University, Meram Faculty of Medicine, Konya, Turkey Critical Care 2007, 11(Suppl 2):P241 (doi: 10.1186/cc5401) Table 1 (abstract P239) APACHE II Mean Inotropic Group Number score age (years) support Mortality A 10 18.5 (8.2) 52 (17) 8 2/10 B 15 20 (5.7) 63 (15) 15 8/15 C 24 22.2 (6.8) 65 (14) 22 15/24 P240 Methods Patients were included who were taken to the emer- gency department due to hypertensive attack. Their age, gender, systolic and diastolic blood pressure were recorded. In order to see the plasma magnesium levels, venous blood samples were taken. The results were compared with a chi-square test. The values P < 0.05 were accepted as significant. Prognostic markers in the acute phase of myocardial infarction P241 The relationship between blood pressure and plasma magnesium level in hypertensive patients Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Figure 1 (abstract P242) Objective To investigate the clinical and prognostic value of TnI release in adult with acute Pc. Figure 1 (abstract P242) Objective To investigate the clinical and prognostic value of TnI release in adult with acute Pc. Methods From January 2000 to March 2006 we retrospectively studied 89 patients with the final diagnosis of acute myocarditis (Mc), of which 66 (74%) fulfilled at least two criteria of acute Pc (typical chest pain, pericardial friction rub, and/or alterations in the ECG). We only included those diagnosed with idiopathic or viral Pc with elevation of TnI over the level of cut for AMI in our hospital (≥0.6 ng/dl). We divided patients into tertiles according to the value of TnI (22 in each group). An echocardiographic (Echoc) study and a ECG monitorization was performed at admission in all. The coronariography was done in 24 (36%), which did not show lesions. The average follow-up was 24 ± 18 months and included Echoc in 61 (92%). Methods From January 2000 to March 2006 we retrospectively studied 89 patients with the final diagnosis of acute myocarditis (Mc), of which 66 (74%) fulfilled at least two criteria of acute Pc (typical chest pain, pericardial friction rub, and/or alterations in the ECG). We only included those diagnosed with idiopathic or viral Pc with elevation of TnI over the level of cut for AMI in our hospital (≥0.6 ng/dl). We divided patients into tertiles according to the value of TnI (22 in each group). An echocardiographic (Echoc) study and a ECG monitorization was performed at admission in all. The coronariography was done in 24 (36%), which did not show lesions. The average follow-up was 24 ± 18 months and included Echoc in 61 (92%). Results Age 28 ± 9 years, 87% men; two (3%) patients had antecedents of idiopathic Pc and only one of Mc. The average of the peak of TnI was 17 ± 11 ng/dl, being the average of the values of TnI in each group of 6 ± 3 (first tertile), 15 ± 2 (second tertile) and 30 ± 11 ng/dl (third tertile). LVEF% was ≥55 in 61 (92%) and there were no differences in the age and sex between the three groups. The elevation of TnI did not correlate with the LVEF% (62 ± 5 vs 61 ± 4 vs 60 ± 7; P = 0.60). Available online http://ccforum.com/supplements/11/S2 P243 Clinical meaning and prognosis of the elevation degree of cardiac Troponin I in pericarditis of the adult: short-term and mid-term follow-up results E Abu Assi, C Peña Gil, R Vidal Perez, J Garcia Acuña, A Amaro Cendon Hospital Clínico Universitario, Santiago de Compostela, Spain Critical Care 2007, 11(Suppl 2):P243 (doi: 10.1186/cc5403) Introduction The inflammatory process of acute pericarditis (Pc) may involve the epicardium and cause myocardial damage, as reflected by cardiac Troponin I (TnI) release. Studies performed surgery patients as well as severely hypertensive patients. Clevidipine is an ultrashort-acting, vascular and arterial-selective calcium antagonist currently under development for treating acute hypertension. Methods We analyzed data from two double-blinded, placebo- controlled trials (ESCAPE-1 and ESCAPE-2) that evaluated the ability of clevidipine to control BP in high-risk cardiovascular surgery patients. In addition, we evaluated the design of a recently initiated trial that analyzes clevidipine in severe hypertension (VELOCITY trial). Results In both ESCAPE-1 and ESCAPE-2, clevidipine demonstrated a statistically significant decrease in mean arterial pressure from baseline (P < 0.0001) compared with placebo at the 5-minute time point. A BP lowering effect was observed within 1–2 minutes with clevidipine, with the median time to achieve target systolic blood pressure (SBP) of 6 and 5.3 minutes, respectively (see Figure 1). In the patients with acute severe hypertension, the VELOCITY trial studies the percentage of patients in whom the SBP falls below the lower limit of a patient- specific predetermined target range at the initial dose of 2.0 mg/hour within 3 minutes of initiating the infusion, as well as the percentage of patients who reach the prespecified target SBP range within 30 minutes of the beginning of the study drug. Conclusion In adults with acute Pc, the elevation degree of TnI is associated with the degree of elevation of the ST segment but it is not a negative prognosis indicator. Emergency electrocardiography-guided pericardiocentesis in cardiac tamponade Emergency electrocardiography-guided pericardiocentesis in cardiac tamponade E Charalambous, S Manousakis, A Kioulpalis, A Skrivanou, G Vrouchos Venizelio General Hospital of Heraklion, Greece Critical Care 2007, 11(Suppl 2):P244 (doi: 10.1186/cc5404) E Charalambous, S Manousakis, A Kioulpalis, A Skrivanou, G Vrouchos Conclusion In both the ESCAPE-1 and ESCAPE-2 studies, clevidipine demonstrated the ability to precisely achieve target blood pressure reductions in a short period of time, in a high-risk patient population. Further analysis of the rapid decreases noted with clevidipine is being conducted in patients with acute severe hypertension in the VELOCITY trial. Introduction Pericardiocentesis (PC) and pericardial fluid drainage is the method of choice in cardiac tamponade (CT). It is usually performed under echocardiography control. The objective of the study was the description of CT etiology, symptoms and clinical findings and the evaluation of the electrocardiography (ECG)- guided PC procedure. P242 Precise and ultrarapid control of blood pressure with clevidipine, an arterial selective calcium channel blocker J Varon1, J Levy2, C Dyke3, P Acosta4, S Aronson5 1The University of Texas, Houston, TX, USA; 2Emory Healthcare, Atlanta, GA, USA; 3Gaston Medical Center, Gastonia, NC, USA; 4Dorrington Medical Associates, Houston, TX, USA; 5DUMC, Durham, NC, USA Critical Care 2007 11(Suppl 2):P242 (doi: 10 1186/cc5402) Results In our model statistically significant independent variables for prediction of inhospital MI complications were HRV frequency domain parameter low-frequency power (LF) on day 3, and left ventricular end-systolic volume (LV ESV), atrial fibrillation/flutter and inotropic agent administration on day 1. According to the results, atrial fibrillation/flutter (odds ratio 25.6) and increased LV ESV (odds ratio 1.067 (6.7%) for increase in 1 ml) increase the probability of inhospital complications, while increased LF on day 3 Introduction Precise, rapid control of blood pressure (BP) is important in emergency and critical care settings as uncontrolled hypertension is associated with morbidity and mortality in high-risk S98 Available online http://ccforum.com/supplements/11/S2 Only the values of TnI in the third tertile were associated with the elevation of the ST segment in ≥5 derivations (P = 0.001), and with abnormal ventricular wall motion (P = 0.046). There was no association with the presence of pericardial effusion, arrhythmias nor cardiac failure. During follow-up, two (3%) patients presented Mc, and three Pc without elevation of TnI. The remaining patients (92%) were asymptomatic and without cardiac dysfunction. The average LVEF% was >55% in all of them surgery patients as well as severely hypertensive patients. Clevidipine is an ultrashort-acting, vascular and arterial-selective calcium antagonist currently under development for treating acute hypertension. Methods We analyzed data from two double-blinded, placebo- controlled trials (ESCAPE-1 and ESCAPE-2) that evaluated the ability of clevidipine to control BP in high-risk cardiovascular surgery patients. In addition, we evaluated the design of a recently initiated trial that analyzes clevidipine in severe hypertension (VELOCITY trial). Results In both ESCAPE-1 and ESCAPE-2, clevidipine demonstrated a statistically significant decrease in mean arterial pressure from baseline (P < 0.0001) compared with placebo at the 5-minute time point. A BP lowering effect was observed within 1–2 minutes with clevidipine, with the median time to achieve target systolic blood pressure (SBP) of 6 and 5.3 minutes, respectively (see Figure 1). In the patients with acute severe hypertension, the VELOCITY trial studies the percentage of patients in whom the SBP falls below the lower limit of a patient- specific predetermined target range at the initial dose of 2.0 mg/hour within 3 minutes of initiating the infusion, as well as the percentage of patients who reach the prespecified target SBP range within 30 minutes of the beginning of the study drug. Conclusion In both the ESCAPE-1 and ESCAPE-2 studies, clevidipine demonstrated the ability to precisely achieve target blood pressure reductions in a short period of time, in a high-risk patient population. Further analysis of the rapid decreases noted with clevidipine is being conducted in patients with acute severe hypertension in the VELOCITY trial. P245 Diagnostic accuracy of automated computerised electrocardiogram interpretation compared with a panel of experienced cardiologists Methods Four hundred and twenty-eight patients with an ACS, admitted to our coronary care unit (CCU), were studied prospectively. Sixty-three per cent presented a non-ST-segment elevation myocardial infarction (NSTEMI) and 37% a ST-segment elevation myocardial infarction (STEMI). During their hospitalization we registered cardiovascular risk factors: we determined the presence of microalbuminuria (>3 mg/dl) in a 24-hour urine sample. We also took blood samples during the first 24 hours of their admittance to the CCU for a complete hemogram, levels of total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, creatinine, creatinine clearance (Cockroft–Gault equation), glucose, HbAc1, high-sensibility C-reactive protein, Cystatin C and a follow-up of levels of Troponin, CK and CK-MB. All patients were submitted to a coronary angiography in the first 72 hours to give a clinical score to their coronary artery disease (disease of one, two or three arteries). A Turley1, A Roberts1, K Evemy2, I Haq2, T Irvine2, P Adams2 1The James Cook University Hospital, Middlesbrough, UK; 2Royal Victoria Infirmary, Newcastle upon Tyne, UK Critical Care 2007, 11(Suppl 2):P245 (doi: 10.1186/cc5405) S100 Introduction Computerised electrocardiogram (ECG) int tation is widely applied, especially within the clinical settin primary care and surgical preadmission. Concerns have raised over the accuracy of computerised ECG interpretatio aim was to compare the performance of computer-based interpretation with that of a panel of experienced cardiologist Methods All consecutive ECGs performed in a hospital card department over a 1-week period were analysed. Two c were assessed, open access patients from primary car surgical preoperative assessment patients. Cardiologists blinded to clinical details and the computerised interpretation. ECGs were analysed by a panel of cardio with the consensus view taken as the reference standard. were interpreted in relation to ‘rhythm’ and ‘other abnorm and were classified as normal or abnormal. Results Seventy consecutive ECGs were analysed, 47 from access and 23 from surgical preassessment. The cohort’s m age was 60 years (range 27–87 years, male n = 30). Twen ECGs were normal. There was complete disagreement ov computerised ECG interpretation of one ECG, which was deem major clinical significance. Partial disagreement occurred remainder. The greatest level of disagreement related t interpretation of left ventricular hypertrophy and ECG eviden myocardial ischaemia/infarction. P246 Cystatin C in the prognostic stratification of patients with an acute coronary syndrome A Lopez Lago, E González Babarro, J García Acuña, S De Lange, E Abu Assi, R Vidal Pérez, M Santás Alvarez, M Jaquet Herter, B Cid Alvárez, J González Juanatey Clinic Universitary Hospital of Santiago, Santiago de Compostela, Spain Critical Care 2007, 11(Suppl 2):P246 (doi: 10.1186/cc5406) Conclusions ‘Classical’ symptoms and signs (low BP, pulsus paradoxus, deep heart sounds or low voltage) can be absent in CT. Emergency PC with ECG intrapericardial ECG recording, after meticulous TTE, can be safe. Appearance of nonmalignant arrhythmias could be a rare complication. Introduction Early risk stratification is essential in the management of patients with an acute coronary syndrome (ACS). Measurements of renal function such as serum creatinine and estimation of creatinine clearance carry independent prognostic information in this population. Cystatin C is a new and better marker of renal function than creatinine. The aim was therefore to evaluate the prognostic value of cystatin C in this population. Methods Four hundred and twenty-eight patients with an ACS, admitted to our coronary care unit (CCU), were studied prospectively. Sixty-three per cent presented a non-ST-segment elevation myocardial infarction (NSTEMI) and 37% a ST-segment elevation myocardial infarction (STEMI). During their hospitalization we registered cardiovascular risk factors: we determined the presence of microalbuminuria (>3 mg/dl) in a 24-hour urine sample. We also took blood samples during the first 24 hours of their admittance to the CCU for a complete hemogram, levels of total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, creatinine, creatinine clearance (Cockroft–Gault equation), glucose, HbAc1, high-sensibility C-reactive protein, Cystatin C and a follow-up of levels of Troponin, CK and CK-MB. All patients were submitted to a coronary angiography in the first 72 hours to give a clinical score to their coronary artery disease (disease of one, two or three arteries). Introduction Early risk stratification is essential in the management of patients with an acute coronary syndrome (ACS). Measurements of renal function such as serum creatinine and estimation of creatinine clearance carry independent prognostic information in this population. Cystatin C is a new and better marker of renal function than creatinine. The aim was therefore to evaluate the prognostic value of cystatin C in this population. P243 Sixty-five percent of patients showed repolarization changes, and only 16% had low voltage. On TTE, 3/4 of patients had right atrium/right ventricle collapse and the intapericardial space measured 1.8–3.8 cm. Only 39% of patients exhibited cardiac enzyme increase (cardiac troponin I, CK- MB), while the majority had elevated CRP. The underlying diagnosis for CT in 35% of cases was lung adenocarcinoma/ nonsmall cell carcinoma or breast carcinoma. In 35% the final diagnosis was that of idiopathic pericarditis. Seventy percent of pericardial fluid samples were exudates and 74% were sanguineous/serosanguineous. Four patients had pericardial fluid under pressure. The mean volume drained was 1,540 ml (850–3,010), the mean period of drainage was 56 hours (3 hours–14 days). No major complications occurred; 23% patients had nonmalignant arrhythmias (AF, NSVT). recognized in 39% and pulsus paradoxus was present in 29% of cases. Only 12% had pericardial knock and pericardial friction rub was absent in all patients. On ECG there was sinus rhythm in 71%, the rest being atrial fibrillation. Sixty-five percent of patients showed repolarization changes, and only 16% had low voltage. On TTE, 3/4 of patients had right atrium/right ventricle collapse and the intapericardial space measured 1.8–3.8 cm. Only 39% of patients exhibited cardiac enzyme increase (cardiac troponin I, CK- MB), while the majority had elevated CRP. The underlying diagnosis for CT in 35% of cases was lung adenocarcinoma/ nonsmall cell carcinoma or breast carcinoma. In 35% the final diagnosis was that of idiopathic pericarditis. Seventy percent of pericardial fluid samples were exudates and 74% were sanguineous/serosanguineous. Four patients had pericardial fluid under pressure. The mean volume drained was 1,540 ml (850–3,010), the mean period of drainage was 56 hours (3 hours–14 days). No major complications occurred; 23% patients had nonmalignant arrhythmias (AF, NSVT). calculated for negative results as there were no false negative results. LR for abnormal ECG ‘rhythm’ were 18.3 (6.7–53.4) and for abnormal ECG ‘other abnormalities’ were 3.15 (2.13–5.11) (Table 1). Conclusions Need exists to improve the diagnostic algorithms used by computerised ECG interpretation. It is essential that all automated computerised ECG interpretations be over read by a physician. P243 Methods Thirty-nine consecutive patients (nine females) with CT, mean age 56 years, underwent 41 emergency PC between November 1998 and November 2006. There was full data registry for 31 patients and 33 PC. We used a subxiphoidal approach in 31 and an apical approach in two cases. Catheters used were Cordigan (Braun) and C-PCS-830-LOCK (Cook). A full transthoracic echocardiography (TTE) study preceded and PC was performed under ECG monitoring (intrapericardial ECG recording). Results Patients with CT had the following symptoms or clinical findings: dyspnea (77%), pleural effusion (68%), chest pain (48%), weight loss (29%), fever (23%), cough (19%), peripheral edema (12%), abdominal pain (12%), hoarseness (12%), jugular vein distension (6%). Forty-five percent of patients were hemo- dynamically stable, while 26% had high BP. The mean heart rate on admission was 94/minute. Seventy-one percent of patients exhibited hypoxemia (half of them mild). Deep heart sounds were Clinical meaning and prognosis of the elevation degree of cardiac Troponin I in pericarditis of the adult: short-term and mid-term follow-up results E Abu Assi, C Peña Gil, R Vidal Perez, J Garcia Acuña, A Amaro Cendon Hospital Clínico Universitario, Santiago de Compostela, Spain Critical Care 2007, 11(Suppl 2):P243 (doi: 10.1186/cc5403) E Abu Assi, C Peña Gil, R Vidal Perez, J Garcia Acuña, A Amaro Cendon Hospital Clínico Universitario, Santiago de Compostela, Spain Critical Care 2007, 11(Suppl 2):P243 (doi: 10.1186/cc5403) Introduction The inflammatory process of acute pericarditis (Pc) may involve the epicardium and cause myocardial damage, as reflected by cardiac Troponin I (TnI) release. Studies performed with TnI demonstrated that the temporal pattern of this release is similar to that of an acute myocardial infarction (AMI); however, the true prognostic significance of TnI remains unknown in this setting. Introduction The inflammatory process of acute pericarditis (Pc) may involve the epicardium and cause myocardial damage, as reflected by cardiac Troponin I (TnI) release. Studies performed with TnI demonstrated that the temporal pattern of this release is similar to that of an acute myocardial infarction (AMI); however, the true prognostic significance of TnI remains unknown in this setting. S99 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin recognized in 39% and pulsus paradoxus was present in 29% of cases. Only 12% had pericardial knock and pericardial friction rub was absent in all patients. On ECG there was sinus rhythm in 71%, the rest being atrial fibrillation. P245 Likelihood ratios (LR) wer Table 1 (abstract P245) Abnormality Kappa Sensitivity Rhythm 0.92 (0.84–1) 1 (0.88–1) Other 0.68 (0.52–0.84) 1 (0.91–1) Introduction Computerised electrocardiogram (ECG) interpre- tation is widely applied, especially within the clinical settings of primary care and surgical preadmission. Concerns have been raised over the accuracy of computerised ECG interpretation. Our aim was to compare the performance of computer-based ECG interpretation with that of a panel of experienced cardiologists. Methods All consecutive ECGs performed in a hospital cardiology department over a 1-week period were analysed. Two cohorts were assessed, open access patients from primary care and surgical preoperative assessment patients. Cardiologists were blinded to clinical details and the computerised ECG interpretation. ECGs were analysed by a panel of cardiologists with the consensus view taken as the reference standard. ECGs were interpreted in relation to ‘rhythm’ and ‘other abnormalities’ and were classified as normal or abnormal. Results We determined the Cystatin C level in 59 patients (16 females and 43 males). In 36% (21 patients) we found normal levels (<0.95; 0.80 ± 0.9), called group 1. In the other group (group 2) we found higher levels of Cystatin C (>0.95; 1.63 ± 0.77). Patients in group 2 presented a higher age, a higher frequency of high blood pressure, worse Killip class score at the moment of admittance, higher inflammatory activity (leucocytosis, P = 0.001 and higher levels of C reactive protein, P = 0.005), higher grade of renal dysfunction (P = 0.001) and anaemia (P = 0.06). Patients in group 2 presented a worse intrahospital prognosis with a higher incidence of cardiac insufficiency (45% to 14%, P = 0.01), ventricular arrhythmias (29% to 5%, P = 0.05), pericardial effusion (18% to 0%, P = 0.05) and a higher mortality (21% to 5%, P = 0.08). In the multivariant analysis, Cystatin C was an independent predictor of cardiac insufficiency (OR = 4.5, 95% CI 1.1–20.8, P = 0.05). Results Seventy consecutive ECGs were analysed, 47 from open access and 23 from surgical preassessment. The cohort’s median age was 60 years (range 27–87 years, male n = 30). Twenty-four ECGs were normal. There was complete disagreement over the computerised ECG interpretation of one ECG, which was deemed of major clinical significance. Partial disagreement occurred in the remainder. The greatest level of disagreement related to the interpretation of left ventricular hypertrophy and ECG evidence of myocardial ischaemia/infarction. P247 P247 The reduction of the glomerular filtration rate and the presence of microalbuminuria at the moment of admittance reduce the prognostics of patients with an acute coronary syndrome A Lopez Lago, J Garcia Acuña, S De Lange, E González Babarro, M Jaquet Herter, E Abu Assi, A Amaro Cendon, M Santás Alvárez, J González Juanatey Clinic Universitary Hospital of Santiago, Santiago de Compostela, Spain Critical Care 2007, 11(Suppl 2):P247 (doi: 10.1186/cc5407) P247 The reduction of the glomerular filtration rate and the presence of microalbuminuria at the moment of admittance reduce the prognostics of patients with an acute coronary syndrome A Lopez Lago, J Garcia Acuña, S De Lange, E González Babarro, M Jaquet Herter, E Abu Assi, A Amaro Cendon, M Santás Alvárez, J González Juanatey Clinic Universitary Hospital of Santiago, Santiago de Compostela, Spain Critical Care 2007, 11(Suppl 2):P247 (doi: 10.1186/cc5407) The reduction of the glomerular filtration rate and the presence of microalbuminuria at the moment of admittance reduce the prognostics of patients with an acute coronary syndrome Background Elevated circulating levels of TNFα, brain natriuretic peptide (BNP) and cardiac Troponin I (cTnI) have been connected with adverse prognosis in patients with chronic heart failure (CHF). However, there are scant data about the predictive value of these biomarkers in combination. Methods A total of 577 consecutive patients (mean age: 73 ± 9 years), who were hospitalized for acute decompensation of NYHA class III/IV (65.3% of ischemic etiology) low-output (mean LVEF: 22 ± 5) CHF, were studied. Biochemical markers were measured upon admission. The incidence of 31-day death was the prespecified primary endpoint. Introduction Determination of the glomerular filtration rate (GFR) in patients with an acute coronary syndrome (ACS) has an important prognostic value. The presence of microalbuminuria (MA) is a known risk factor in patients with hypertension and diabetes. We know less about the effect of reduction of the GFR on patients with an ACS. Results The incidence of the primary endpoint was 17.7%. By multivariate Cox analysis, including baseline characteristics and the study biomarkers, elevated circulating levels of TNFα (RR = 2.1; P < 0.001), BNP (RR = 3.5; P < 0.001) and cTnI (RR = 3.8; P < 0.001) were independently associated with the primary endpoint. P248 Circulating levels of tumor necrosis factor alpha, brain natriuretic peptide and cardiac Troponin I upon admission and 31-day mortality in patients with acute decompensated chronic heart failure P Batika Zairis1, M Zairis2, E Adamopoulou2, H Michalopoulou1, S Foussas2 1Metaxa Hospital, Piraeus, Greece; 2Tzanio Hospital, Piraeus, Greece Critical Care 2007, 11(Suppl 2):P248 (doi: 10.1186/cc5408) P Batika Zairis1, M Zairis2, E Adamopoulou2, H Michalopoulou1, S Foussas2 P245 Likelihood ratios (LR) were not Table 1 (abstract P245) Abnormality Kappa Sensitivity Specificity NPV PPV Rhythm 0.92 (0.84–1) 1 (0.88–1) 0.95 (0.85–0.98) 1 (0.93–1) 0.9 (0.76–0.97) Other 0.68 (0.52–0.84) 1 (0.91–1) 0.68 (0.68–0.53) 1 (0.88–1) 0.75 (0.62–0.85) S100 Available online http://ccforum.com/supplements/11/S2 Conclusion Higher levels of Cystatin C (>0.95) in patients with an ACS indicate a worse intrahospital prognosis and also a higher inflammatory activity and renal dysfunction. Conclusion Higher levels of Cystatin C (>0.95) in patients with an ACS indicate a worse intrahospital prognosis and also a higher inflammatory activity and renal dysfunction. P247 When the patients were divided according to the number of positive biomarkers (estimated by ROC analysis) there was a significant gradual increase in the rate of the primary endpoint with increasing of the number of the positive biomarkers (4.1%, 10%, 21.5% and 53.5% 31-day mortality rate for patients with zero, one, two and three positive biomarkers, respectively; P < 0.001) (Figure 1). Method Four hundred and twenty-eight patients with an ACS, admitted to our coronary care unit (CCU), were studied prospectively. Sixty-three percent presented a non-ST-segment elevation myocardial infarction and 37% a ST-segment elevation myocardial infarction. During their hospitalization we registered cardiovascular risk factors; we determined the presence of MA (>3 mg/dl) in a 24-hour urine sample. We also took blood samples during the first 24 hours of their admittance to the CCU for a complete hemogram, levels of total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, creatinine, creatinine clearance (Cockroft–Gault equation), glucose, HbAc1, high-sensibility C- reactive protein and a follow-up of levels of Troponin, CK and CK- MB. P250 P250 Cardiopulmonary exercise testing as a screening test for perioperative management of major cancer surgery: a pilot study R Raobaikady, S Dinesh, M Hacking, T Wigmore The Royal Marsden NHS Foundation Trust, London, UK Critical Care 2007, 11(Suppl 2):P250 (doi: 10.1186/cc5410) Cardiopulmonary exercise testing as a screening test for perioperative management of major cancer surgery: a pilot study R Raobaikady, S Dinesh, M Hacking, T Wigmore The Royal Marsden NHS Foundation Trust, London, UK Critical Care 2007, 11(Suppl 2):P250 (doi: 10.1186/cc5410) Introduction Cardiopulmonary exercise testing is an important screening test to evaluate cardiorespiratory function before major body cavity surgery. Introduction Cardiopulmonary exercise testing is an important screening test to evaluate cardiorespiratory function before major body cavity surgery. Introduction Over the past decade, coronary revascularisation has helped reduce mortality and morbidity rates from coronary artery disease. In addition to revascularisation, long-term prognosis is dependent on successful implementation of secondary prevention, in particular the use of aspirin, statins, angiotensin-converting enzyme (ACE) inhibitors and, in many, β-blockers. Previous studies have highlighted the under-utilisation of secondary preventative strategies in this patient population. A focused review of secondary preventative medication at the time of revascularisation provides an excellent opportunity to ensure optimal use of these agents. Our aim was to identify the proportion of patients undergoing nonemergency surgical revascularisation discharged on these four secondary preventative medications. Objective To develop a clinical strategy for the identification and management of high-risk major cancer surgical patients in order to reduce perioperative morbidity and mortality. Methods Forty-one major cancer surgery patients underwent a cardiopulmonary exercise test (CPX) as part of their preoperative assessment. Their cardiac and pulmonary risk factors were analysed. Depending on the anaerobic threshold (AT) values, patients are considered poor risk, moderate risk or very low risk for surgery. Results Three patients did not complete the test. Two of them had very poor cardiopulmonary reserve and one had leg fatigue with good pulmonary function. Seven patients were considered high risk with AT < 10. The remaining 31 patients had AT > 11 and underwent major cancer surgery. In total, 10 surgical procedures were cancelled based on poor CPX performance. Two patients with low AT underwent surgery after preoptimisation with no complications. There are no deaths related to cardiopulmonary complications in any patient deemed fit for major cancer surgery and intensive care management, as determined by CPX testing. P250 The average intensive care stay was 8.9 days (range 1–19 days). The surgical procedure was altered in two patients based on CPX results. Methods A retrospective analysis of our inhouse cardiothoracic surgical database was performed. All patients had undergone surgical revascularisation between January 2003 and November 2006. Only patients undergoing coronary artery bypass grafting were included. Results A total of 2,749 consecutive patients were included in the analysis, mean age 65.5 years (±9.2). In total, 2,302 isolated coronary artery bypass grafting procedures and 447 combined procedures were performed. See Table 1. Table 1 (abstract P249) 2003 2004 2005 2006 Total 522 758 767 702 Previous myocardial 296 364 353 347 infarction (56.7%) (48%) (46%) (49.4%) Left ventricular 113 145 175 186 systolic dysfunction (21.6%) (19.1%) (22.8%) (26.5%) EuroSCORE 3.8 (2.7) 3.9 (3) 3.9 (2.8) 4.3 (2.9) Aspirin 490 694 700 652 (93.9%) (91.6%) (91.3%) (92.9%) ACE inhibitor/ 285/34 421/43 430/53 382/49 angiotensin receptor (61%) (61%) (63%) (61%) blocker β-Blocker 412 632 587 540 (78.9%) (83.4%) (76.5%) (76.9%) Statin 470 700 710 638 (90%) (92.3%) (92.6%) (90.9%) Discussion CPX testing is an important screening test for major surgery to determine the cardiorespiratory risk factors. It is useful in reducing surgical perioperative mortality and avoids unnecessary intensive care admissions after major body cavity surgeries. The CPX test is also useful in perioperative anaesthetic management. It may not predict morbidity and the average intensive care stay. It is very useful in selecting patients for preoptimisation before major cancer surgery. Conclusion Preoperative screening using CPX testing is useful in identification of high-risk cancer surgical patients and the appropriate selection of perioperative management. Figure 1 (abstract P248) Conclusions The present results suggest that in patients hospitalized due to acutely decompensated severe low-output CHF, serum levels of TNFα, BNP and cTnI can be used in combination for enhanced early risk stratification. Results Thirty-nine percent of the patients with an ACS presented a GFR less than 60 ml/minute, and 36% presented MA at the moment of admittance to the CCU. Forty-four percent of the patients with a GFR less than 60 ml/minute also presented MA; on the contrary, only 32% of the patients with a GFR more than 60 ml/minute did so (P = 0.01). This group contains significantly more women (P = 0.001), more history of ischemic brain events and peripheral artery disease (P = 0.03), worse Killip score at the moment of admittance (P = 0.001), more development of cardiac insufficiency (P = 0.003) and a higher mortality during hospital stay (P = 0.03). The intrahospital survival of patients with GFR less than 60 ml/minute and MA was 79%, to 96% in patients without MA and a GFR more than 60 ml/minute (P = 0.01; Log-rank test = 6). Patients with a GFR less than 60 ml/minute but without MA presented an intrahospital survival of 85%. In the multivariant analysis a GFR less than 60 ml/minute (OR = 2.0; 95% CI 1.13–3.53) and the presence of MA (OR = 2.30; 95% CI 1.37–3.86) were independent predictive factors of cardiac insufficiency and mortality. Conclusions The present results suggest that in patients hospitalized due to acutely decompensated severe low-output CHF, serum levels of TNFα, BNP and cTnI can be used in combination for enhanced early risk stratification. Conclusions The presence of a GFR less than 60 ml/minute and MA at the moment of admittance of a patient with an ACS identifies a group of patients with a bad prognosis. Future studies can reveal whether an improvement of the renal function can be beneficial for this group of patients. S101 P249 Secondary prevention following surgical revascularisation: continuing under-use of angiotensin-converting enzyme inhibitors A Turley, A Thornley, A Roberts, R Morley, W Owens, M de Belder The James Cook University Hospital, Middlesbrough, UK Critical Care 2007, 11(Suppl 2):P249 (doi: 10.1186/cc5409) P249 Secondary prevention following surgical revascularisation: continuing under-use of angiotensin-converting enzyme inhibitors A Turley, A Thornley, A Roberts, R Morley, W Owens, M de Belder The James Cook University Hospital, Middlesbrough, UK Critical Care 2007, 11(Suppl 2):P249 (doi: 10.1186/cc5409) Low-dose dobutamine after surgery in high-risk patients: effects on postoperative complications Low-dose dobutamine after surgery in high-risk patients: effects on postoperative complications Low-dose dobutamine after surgery in high-risk patients: effects on postoperative complications S Lobo, A Arantes, A Christiano Junior, S de Abreu, J de Moraes, J Gandolfi, L Leite Faculdade de Medicina de São José do Rio Preto, Brazil Critical Care 2007, 11(Suppl 2):P251 (doi: 10.1186/cc5411) S Lobo, A Arantes, A Christiano Junior, S de Abreu, J de Moraes, J Gandolfi, L Leite Faculdade de Medicina de São José do Rio Preto, Brazil Critical Care 2007, 11(Suppl 2):P251 (doi: 10.1186/cc5411) Conclusion Although the utilisation of these preventive therapies has improved compared with previous studies, additional improvements could be made and in particular there is a continuing under-utilisation of ACE inhibitors. There are several reasons why ACE inhibitors might not be used in the early postoperative phase (hypotension, temporary renal dysfunction, etc.). These results reinforce the need to review these patients following recovery from surgery with a view to optimising secondary preventive treatment. This may best be done in community secondary prevention clinics with agreed guidelines. Introduction Dobutamine may have a role in increasing splanchnic perfusion, thereby protecting this area from further injury. We aimed to investigate the effects of low-dose dobutamine (5 µg/kg/min) on tissue perfusion and postoperative complications in high-risk patients. Introduction Dobutamine may have a role in increasing splanchnic perfusion, thereby protecting this area from further injury. We aimed to investigate the effects of low-dose dobutamine (5 µg/kg/min) on tissue perfusion and postoperative complications in high-risk patients. Methods A prospective, randomized, blinded and placebo- controlled study. One hundred surgical patients admitted to a step- down unit were evaluated and 82 patients were enrolled, 42 for the control group (saline) and 40 for the dobutamine group (5 µg/kg/hour during 24 hours). The same therapeutic goals were S102 Available online http://ccforum.com/supplements/11/S2 P252 Results Gastrointestinal complications occurred in 63 patients, while in 35 patients appeared transient episodes of gut mucosal ischemia. Sixteen patients presented mesenteric ischemia, six paralytic ileus, six colonic obstruction, two lower gastrointestinal bleeding, two upper gastrointestinal bleeding, two perforated duodenal ulcer and one rectal perforation. Intestinal complications correlated with advanced age (67.5 ± 12 years), preoperative congestive heart failure and peripheral vascular disease, prolonged bypass time (156 ± 91.7 min) and aortic cross-clump time (97.6 ± 44.45 min), the number of blood and plasma transfusions, re-exploration of the chest, the administration of inotrops (70%) and the usage of a intra-aortic balloon pump (42%). The mean EuroSCORE value was 12.72 ± 3.8. The majority of patients presented at the end of the first postoperative week. Fifteen patients died (48%). Methods A prospective survey was conducted among 4,588 patients undergoing cardiac surgery and attending the surgical ICU from 1 January 2002 to 31 December 2004. All case histories of patients were objected to meticulous analysis searching for complications involving gastrointestinal tract and requiring surgical consultation. Patients with minor disorders were excluded from the study. We performed a multivariable logistic regression analysis to identify the risk factors for development of postoperative intestinal complications. Results Gastrointestinal complications occurred in 63 patients, while in 35 patients appeared transient episodes of gut mucosal ischemia. Sixteen patients presented mesenteric ischemia, six paralytic ileus, six colonic obstruction, two lower gastrointestinal bleeding, two upper gastrointestinal bleeding, two perforated duodenal ulcer and one rectal perforation. Intestinal complications correlated with advanced age (67.5 ± 12 years), preoperative congestive heart failure and peripheral vascular disease, prolonged bypass time (156 ± 91.7 min) and aortic cross-clump time (97.6 ± 44.45 min), the number of blood and plasma transfusions, re-exploration of the chest, the administration of inotrops (70%) and the usage of a intra-aortic balloon pump (42%). The mean EuroSCORE value was 12.72 ± 3.8. The majority of patients presented at the end of the first postoperative week. Fifteen patients died (48%). Conclusion Various predictors of hypoperfusion have been tested in critically ill patients and correlations have been found for O2 and CO2 derived parameters. Long ECC time plays a major role in the balance between VO2 and DO2; O2 and CO2 derived parameters could be useful markers to detect anaerobic metabolism in cardiac surgical patients. Combined metabolic parameters and gas exchange to predict morbidity after extracorporeal circulation Combined metabolic parameters and gas exchange to predict morbidity after extracorporeal circulation S Scolletta, E Maglioni, F Franchi, P Giomarelli, B Biagioli University of Siena, Italy Critical Care 2007, 11(Suppl 2):P253 (doi: 10.1186/cc5413) Results Complications occurred in 35% and 50% of the patients in the dobutamine and control groups, respectively (RR 0.70, 95% CI 0.41–1.17; not significant). The patients in whom dobutamine was interrupted due to persistent tachycardia despite fluid replacement had more complications (75% vs 40.6%; RR 1.85, 95% CI 1.03–3.29, P < 0.05), higher mortality (62.5% vs 12.5%; RR 5.0, 95% CI 1.72–14.46, P < 0.05) and lower central venous oxygen saturation (55% ± 15% vs 70% ± 16%; P = 0.021) in comparison with patients tolerant to dobutamine infusion. Introduction Under normal resting conditions, the oxygen delivery (DO2) matches the overall metabolic demands of the organs, the oxygen consumption (VO2) is about 25% of the DO2, and energy is produced basically through the aerobic mechanism. In cardiac surgery with extracorporeal circulation (ECC), several factors (for example, hemodilutional anemia, myocardial stunning resulting in a low cardiac output (CO)) can determine an imbalance between O2 demand and DO2 and may affect the outcome. Below the critical DO2 there is a linear decrease of both VO2 and CO2 production (VCO2), but due to the anaerobic VCO2 the respiratory quotient increases. This study is aimed to evaluate the role of O2 and CO2 derived parameters to predict postoperative morbidity in cardiac surgery. Conclusion Low-dose dobutamine after surgical trauma has no effects on the prevalence of postoperative complications in high- risk surgical patients. Morbimortality was significantly higher in patients with severe occult hypoperfusion. P253 applied for both groups. The presence of tachycardia or hypotension in response to study drug infusion was considered a signal of occult hypoperfusion and deemed a need for fluid replacement, which was given according to an algorithm. Results Complications occurred in 35% and 50% of the patients in the dobutamine and control groups, respectively (RR 0.70, 95% CI 0.41–1.17; not significant). The patients in whom dobutamine was interrupted due to persistent tachycardia despite fluid replacement had more complications (75% vs 40.6%; RR 1.85, 95% CI 1.03–3.29, P < 0.05), higher mortality (62.5% vs 12.5%; RR 5.0, 95% CI 1.72–14.46, P < 0.05) and lower central venous oxygen saturation (55% ± 15% vs 70% ± 16%; P = 0.021) in comparison with patients tolerant to dobutamine infusion. applied for both groups. The presence of tachycardia or hypotension in response to study drug infusion was considered a signal of occult hypoperfusion and deemed a need for fluid replacement, which was given according to an algorithm. P252 Intestinal complications associated with cardiovascular surgical procedures S Mastoraki, E Mastoraki, L Douka, I Kriaras, S Geroulanos Onassis Cardiac Surgery Center, Athens, Greece Critical Care 2007, 11(Suppl 2):P252 (doi: 10.1186/cc5412) Intestinal complications associated with cardiovascular surgical procedures Methods Eight hundred and twenty-seven consecutive adult patients who underwent coronary surgery were studied. We selected 38 intraoperative and postoperative O2 and CO2 derived parameters, which could be associated with postoperative morbidity. Postoperative data were collected in the first 3 hours after admission to the ICU. The influence of each predictor on outcome was analyzed. Morbidity was defined as one or more of the following events: cardiovascular, respiratory, neurological, renal, infectious, and hemorrhagic complications. Univariate and multivariate analyses were performed. ROC curve analysis was also used to define the best predictive variables. S Mastoraki, E Mastoraki, L Douka, I Kriaras, S Geroulanos Onassis Cardiac Surgery Center, Athens, Greece Critical Care 2007, 11(Suppl 2):P252 (doi: 10.1186/cc5412) Introduction Intestinal complications after cardiopulmonary bypass procedures are infrequent but they carry a significant incidence of morbidity and mortality. Predictors of these complications are not well developed, and the role of fundamental variables remains controversial. The purpose of this study was to ascertain the frequency of intestinal complications following open heart surgery, to assess preoperative predisposing factors and to elucidate that prompt diagnosis and institution of therapy are the most common factors to improve the outcome. Results Intraoperative predictors of morbidity were ECC and aortic cross-clamp times, and lowest hematocrit during ECC. The area under the ROC curve (AUC) was 0.74 for the lowest hematocrit on ECC, and its cutoff value was 24%. Among the postoperative variables, DO2, oxygen extraction ratio (O2ER), DO2/VCO2 ratio, and VCO2/CO ratio were related to morbidity. The AUCs for oxygen and CO2 derived parameters were 0.80, 0.76, 0.75, and 0.70 (DO2, O2ER, DO2/VCO2 ratio, and VCO2/CO ratio, respectively). The best predictive cutoff values were 590 ml/minute, 38%, 3.9, and 40, for DO2, O2ER, DO2/VCO2 ratio, and VCO2/CO ratio, respectively. p Methods A prospective survey was conducted among 4,588 patients undergoing cardiac surgery and attending the surgical ICU from 1 January 2002 to 31 December 2004. All case histories of patients were objected to meticulous analysis searching for complications involving gastrointestinal tract and requiring surgical consultation. Patients with minor disorders were excluded from the study. We performed a multivariable logistic regression analysis to identify the risk factors for development of postoperative intestinal complications. P255 Role of plasminogen activator inhibitor-1 polymorphism on the development of vasoplegic syndrome associated with cardiopulmonary bypass J Jimenez, J Iribarren, M Brouard, Y Barrios, J Raya, L Lorente, R Perez, C Garcia, J Martinez, R Martinez, M Mora Hospital Universitario de Canarias, La Laguna, Santa Cruz, Tenerife, Spain Critical Care 2007, 11(Suppl 2):P255 (doi: 10.1186/cc5415) Introduction Vasoplegic syndrome (VS) after cardiac surgery with cardiopulmonary bypass (CPB) can vary from mild to severe complication and it appears with an incidence ranging between 5% and 15%. The etiology is not completely elucidated but risk factors such as temperature and duration of cardiopulmonary bypass and preoperative treatment with angiotensin-converting enzyme (ACE) inhibitors have been associated [1]. We wanted to investigate the possible role of several genetic polymorphisms in patients with VS after elective CPB. Introduction Vasoplegic syndrome (VS) after cardiac surgery with cardiopulmonary bypass (CPB) can vary from mild to severe complication and it appears with an incidence ranging between 5% and 15%. The etiology is not completely elucidated but risk factors such as temperature and duration of cardiopulmonary bypass and preoperative treatment with angiotensin-converting enzyme (ACE) inhibitors have been associated [1]. We wanted to investigate the possible role of several genetic polymorphisms in patients with VS after elective CPB. Results Seventeen (34%) patients had VS, 11 (65%) men and six (35%) women. Longer aortic clamping time (P = 0.007) and CPB time (P = 0.013) were associated with VS. These patients showed a higher cardiac index at 4 hours (P < 0.001) and lactic acid within the first 24 hours. Seven of these patients (41%) fulfilled vasoplegic shock criteria (P < 0.001). We found higher levels of IL-6 at 0 hours (P = 0.02) and 4 hours (P = 0.001), and soluble TNF receptor at 0 hours (P = 0.044). At ICU admission (0 hours) there was a higher coagulation activation: INR (P = 0.005), fibrinogen (P = 0.001), antithrombin (P = 0.007); lower levels of plasminogen activator inhibitor-1 (P = 0.023) as well as lower plasminogen activator inhibitor-1/tissue-plasminogen activator ratio (P = 0.021), and higher levels of D-dimer (P = 0.041); lower levels of C3 (P = 0.023), B factor (P = 0.013), C4 (P = 0.015) as well as a significantly higher decrease between preoperative and 0-hour levels of C1-inhibitor, C4, C3 and B factor. Lower levels of leptins at 0, 4 and 24 hours were found. P254 Vasoplegic syndrome after cardiopulmonary bypass surgery – associated factors and clinical outcomes: a nested case–control study J Iribarren, J Jimenez, M Brouard, J Lorenzo, R Perez, L Lorente, C Nuñez, L Lorenzo, C Henry, R Martinez, M Mora Hospital Universitario de Canarias, La Laguna, Santa Cruz, Tenerife, Spain Critical Care 2007, 11(Suppl 2):P254 (doi: 10.1186/cc5414) Vasoplegic syndrome after cardiopulmonary bypass surgery – associated factors and clinical outcomes: a nested case–control study J Iribarren, J Jimenez, M Brouard, J Lorenzo, R Perez, L Lorente, C Nuñez, L Lorenzo, C Henry, R Martinez, M Mora Hospital Universitario de Canarias, La Laguna, Santa Cruz, Tenerife, Spain Critical Care 2007, 11(Suppl 2):P254 (doi: 10.1186/cc5414) Conclusions Intestinal complications after cardiac surgery are uncommon but life-threatening and may result from ischemic mucosal injury, which increases mucosal permeability and promotes the translocation of bacterial toxins and the release of mediators. Clinical features are often subtle and a high index of suspicion is necessary for an early diagnosis and the institution of appropriate treatment. Introduction Vasoplegic syndrome (VS) following heart surgery using cardiopulmonary bypass (CPB) has been recently recognized and implicated in life-threatening complications. The Introduction Vasoplegic syndrome (VS) following heart surgery using cardiopulmonary bypass (CPB) has been recently recognized and implicated in life-threatening complications. The S103 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Conclusions VS post-CPB was associated with activation of serin protease systems, which leads to higher blood loss and excessive bleeding. aim of this study was to identify associated factors for the development of VS after CPB. Methods We performed a nested case–control study of 50 patients undergoing CPB, 27 (54%) men and 23 (46) women, mean age 66.5 (SD 9.6) years. VS was defined as systemic vascular resistance index <1,600 dyn•seg/cm5/m2 and cardiac index >2.5 l/min/m2 within the first postoperative 4 hours. Vasoplegic shock was defined as vasoplegic patients that needed norepinephrine for at least 4 hours, after failure to respond to appropriate volume expansion. Excessive bleeding was defined as blood loss >1 l/24 hours, while total bleeding was considered as blood loss until chest tube withdrawal. Demographic variables, surgical procedures and postoperative variables were collected. We recorded data related to coagulation, fibrinolysis, complement, inflammation, blood loss at different time points, preoperative, at 0, 4 and 24 hours after surgery, and hemoderivative requirements. P254 We used the Pearson chi-squared test, the Fisher exact test, the Student t test and the Mann–Whitney U test for nonparametric variables. SPSS version 12.1 was used. P255 Vasoplegic patients showed higher blood losses along all time points (Figure 1), higher incidence of excessive bleeding (60% vs 40%; P = 0.011) and required more hemoderivatives during the ICU stay, plasma (P = 0.016) and platelets (P = 0.002). Methods We performed a nested case–control study of 50 patients undergoing CPB, 27 (54%) men and 23 (46) women, mean age 66.5 (SD 9.6) years. VS was defined as systemic vascular resistance index lower than 1,600 dyn•seg/cm5/m2 and a cardiac index greater than 2.5 l/min/m2 within the first 4 hours after surgery. We recorded data related to hemodynamic parameters at different postoperative time points, at ICU admission (0 hours), 4 and 24 hours after surgery, and the polymorphism of the following genes: plasminogen activator inhibitor-1 (PAI-1) and β-TNF + 250. In addition, 23 neutral markers were genotyped to follow genomic control strategies that would detect spurious associations due to population substructure. We used the Pearson chi-squared test and binary logistic regression. SPSS version 12.1 was used. Results We observed 17 (34%) patients with vasoplegia criteria, 11 (65%) men and six (35%) women, age 67 (61–72) years. The only one associated with VS was the PAI-1 polymorphism, and its distribution in the study population was: 4G/G genotype in 10 (20%) patients, 4G/5G in 26 (52%) patients, and 5G/G in 14 Available online http://ccforum.com/supplements/11/S2 Methods We performed a nested case–control study of 26 patients, who did not receive antifibrinolytic prophylaxis. We used Bray’s classification for BMI: lower than 27 kg/m2; 27–30 kg/m2; higher than 30 kg/m2. Variables were collected preoperatively, at ICU admission (0 hours), and at 4 and 24 hours after surgery. Excessive bleeding was defined as blood loss higher than 1 l in the first 24 hours after intervention. The associations of BMI with demographic factors, leptin levels, coagulation, fibrinolysis and complement parameters were analyzed. Pearson’s chi-squared test and Fisher’s exact test were used, the Student t test for independent groups and the Mann–Whitney U test for nonparametric variables. Conclusions The PAI-1 polymorphism (homozygous 5G/G) was independently associated with the onset of VS. 1. Carrel T, Englberger L, Mohacsi P, Neidhart P, Schmidli J: Low systemic vascular resistance after cardiopulmonary bypass: incidence, etiology, and clinical importance. J Card Surg 2000, 15:347-353. P256 Results In total, 61.5% of patients showed BMI >27 kg/m2 (median 28 kg/m2, range 25.2–30.7 kg/m2). Patients with BMI lower than 26.4 kg/m2 (25–28 kg/m2) presented excessive bleeding (P = 0.026). Leptin levels after adjusting by BMI were significantly associated with excessive bleeding at all postoperative time points (P < 0.001, P < 0.001 and P = 0.004, respectively) (Figure 1). BMI presented a direct correlation with leptins, fibrinogen and plasminogen activator inhibitor-1 (PAI-1) on arrival, meanwhile 24-hour bleeding showed an inverse correlation with the same parameters and BMI (Table 1). Patients with BMI < 27 kg/m2 had significantly greater coagulation, fibrinolysis and complement activation. Therefore these patients required significantly greater hemoderivatives. Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 postoperative bleeding after cardiopulmonary bypass (CPB) has been found in several studies recently. Nevertheless the strong relationship between a low BMI and excessive bleeding remains unexplained. We sought to investigate the BMI role on postoperative bleeding and its relationship with leptin levels, coagulation, fibrinolysis and complement parameters. Methods We performed a nested case–control study of 26 patients, who did not receive antifibrinolytic prophylaxis. We used Bray’s classification for BMI: lower than 27 kg/m2; 27–30 kg/m2; higher than 30 kg/m2. Variables were collected preoperatively, at ICU admission (0 hours), and at 4 and 24 hours after surgery. Excessive bleeding was defined as blood loss higher than 1 l in the first 24 hours after intervention. The associations of BMI with demographic factors, leptin levels, coagulation, fibrinolysis and complement parameters were analyzed. Pearson’s chi-squared test and Fisher’s exact test were used, the Student t test for independent groups and the Mann–Whitney U test for nonparametric variables. Results In total, 61.5% of patients showed BMI >27 kg/m2 (median 28 kg/m2, range 25.2–30.7 kg/m2). Patients with BMI lower than 26.4 kg/m2 (25–28 kg/m2) presented excessive bleeding (P = 0.026). Leptin levels after adjusting by BMI were significantly associated with excessive bleeding at all postoperative time points (P < 0.001, P < 0.001 and P = 0.004, respectively) (Figure 1). BMI presented a direct correlation with leptins, fibrinogen and plasminogen activator inhibitor-1 (PAI-1) on arrival, meanwhile 24-hour bleeding showed an inverse correlation with the same parameters and BMI (Table 1). Patients with BMI < 27 kg/m2 had significantly greater coagulation, fibrinolysis and complement activation. Therefore these patients required significantly greater hemoderivatives. (28%) patients. According to the PAI-1 polymorphism, vasoplegia criteria were found in one (5.5%) 4G/G carrier, in seven (39%) 4G/5G carriers and in 10 (55.5%) 5G/G carriers (P = 0.012) (Figure 1). The post-hoc power for PAI-1 polymorphism and vasoplegia was 0.85. After controlling for temperature, clamping time, antifibrinolytics, body mass index and ACE inhibitors, the 5G/G genotype was independently associated with vasoplegia (P = 0.017); OR: 24.6 (95% CI: 1.8–342). postoperative bleeding after cardiopulmonary bypass (CPB) has been found in several studies recently. Nevertheless the strong relationship between a low BMI and excessive bleeding remains unexplained. We sought to investigate the BMI role on postoperative bleeding and its relationship with leptin levels, coagulation, fibrinolysis and complement parameters. Figure 1 (abstract P257) Methods We performed a nested case–control study of 50 patients undergoing CPB, 27 (54%) men and 23 (46) women, mean age 66.5 (SD 9.6) years. Excessive bleeding (EB) was defined as blood loss higher than 1 l over the 24 hours. Demographic variables, comorbid conditions, surgical procedures and postoperative variables were collected. We recorded data related to coagulation, fibrinolysis, complement, and blood loss at different time points, preoperative, at ICU admission (0 hours) and 4 and 24 hours after surgery. We used the Pearson chi-squared test, the Fisher exact test, the Student t test and the Mann–Whitney U test for nonparametric variables and Spearman’s rho for nonparametric correlations. Figure 1 (abstract P257) Results EB patients had higher activation of classical, alternative and final pathways of complement at 0 and 4 hours. Also we found a significantly higher decreasing of several components of complement from preoperative values to postoperative values (0 and 4 hours) associated with EB. This decrease of complement was correlated with a similar decrease of platelets and anti- thrombin levels between the preoperative period and 0 hours, and an increase of D-dimer levels in the first 4 hours. Conclusions Complement activation was associated with EB due, in part, to a greater activation of platelets, coagulation and fibrinolysis. Table 1 (abstract P257) ICU arrival BMI 24-hour bleeding Rho P Rho P Leptins 0.46 0.02 –0.57 0.02 Fibrinogen 0.51 <0.01 –0.49 <0.01 PAI-1 0.40 0.04 –0.64 <0.01 Conclusions Lower BMI was associated with higher postoperative bleeding and lower procoagulant factor levels. Table 1 (abstract P257) P257 Impact of body mass index on postoperative bleeding in cardiopulmonary bypass Complement activation and excessive bleeding in cardiopulmonary bypass surgery J Iribarren, J Jimenez, M Brouard, R Galvan, L Lorente, R Perez, B Alarco, M Diaz, J Malaga, S Huidobro, R Martinez, M Mora Hospital Universitario de Canarias, La Laguna, Santa Cruz, Tenerife, Spain Critical Care 2007, 11(Suppl 2):P256 (doi: 10.1186/cc5416) Introduction Complement activation has been associated with postoperative bleeding. We investigated the association between complement activation, coagulation and fibrinolysis systems, and postoperative excessive bleeding in cardiopulmonary bypass (CPB) surgery. Introduction Complement activation has been associated with postoperative bleeding. We investigated the association between complement activation, coagulation and fibrinolysis systems, and postoperative excessive bleeding in cardiopulmonary bypass (CPB) surgery. Figure 1 (abstract P254) Figure 1 (abstract P254) 4 Figure 1 (abstract P254) Figure 1 (abstract P255) Figure 1 (abstract P255) Figure 1 (abstract P255) S104 Available online http://ccforum.com/supplements/11/S2 E Borotto1, D Tüller1, S Krähenbühl2, D Mettler1, J Takala1, S Jakob1 1University Hospital Bern, Switzerland; 2University Hospital Basel, Switzerland Critical Care 2007, 11(Suppl 2):P258 (doi: 10.1186/cc5418) Introduction Endotoxemia and hemorrhage may both affect mitochondrial function. We aimed to characterize the impact of a short-term, three-hit hemorrhage/endotoxemia model on liver and skeletal muscle mitochondrial respiration. Results Hyperdynamic circulation developed in F with increasing DO2,h and decreasing VO2,h (Table 1). Complex II activity signifi- cantly decreased from 19.3 ± 4.2 to 9.5 ± 2.6 (P < 0.05 vs BL and between groups) in F compared with C. Complex I–III–IV function decreased in parallel in F. Methods Seven anesthetized pigs were bled (blood loss 20%) and retransfused to euvolemia before and after endotoxin infusion (0.4 µg/kg/hour for 2 hours). The cardiac index (CI) (thermodilution) and systemic mean arterial pressure (MAP) were recorded. State 3/4 respiration (nanoatom O2/min/mg protein for glutamate) was assayed from tissue samples at baseline (muscle) and the end of the experiment (muscle and liver). Hepatic mitochondrial respiration was compared with controls (n = 6). Table 1 (abstract P259) BL 12 hours 24 hours MAP F 78 ± 22 98 ± 25 81 ± 19 MAP C 91 ± 4 101 ± 12 94 ± 6 TLF F 17 ± 1 46 ± 11* 50 ± 5* TLF C 23 ± 7 35 ± 4 39 ± 7† DO2,h F 2.0 ± 0.6 3.8 ± 0.2 5.4 ± 1† DO2,h C 1.9 ± 0.4 3.2 ± 0.4 3.5 ± 0.4 VO2,h F 0.8 ± 0.2 0.6 ± 0.1 0.5 ± 0.1 VO2,h C 1.5 ± 0.7 1.1 ± 0.1 0.9 ± 0.4 *P < 0.05 vs BL and between groups. †P < 0.05 vs BL. Results One pig died earlier (not included). Data are presented as the median (range). P < 0.05, Friedman test. Muscle mitochondrial respiration was similar at baseline and the end of experiment; state 3 (317 (222–594) vs 409 (295–468)), state 4 (29 (22–58) vs 40 (31–49)), respiratory control ratio (11 (7–15) vs 10 (9–11)) (not significant). Hepatic mitochondrial state 4 was higher (27 (16–31) vs 19 (13–22)) and respiratory control ratio lower (3 (3–4) vs 5 (4–6)) in the hemorrhage/endotoxemia group, compared with controls. *P < 0.05 vs BL and between groups. †P < 0.05 vs BL. Real-time monitoring of mitochondrial function in the urethral wall Real-time monitoring of mitochondrial function in the urethral wall Real-time monitoring of mitochondrial function in the urethral wall S Preisman1, E Segal1, V Glauber1, E Heldenberg1, R Walden1, D Givony2, N Dekel2, L Oren2, E Pewzner2, A Mayevsky3, A Perel1 1Sheba Medical Center, Tel-Hashomer, Rama-Gan, Israel; 2CritiSense Ltd, Givat Shmuel, Israel; 3Bar-Ilan University, Ramat-Gan, Israel Critical Care 2007, 11(Suppl 2):P260 (doi: 10.1186/cc5420) PAP, pulmonary artery pressure. P < 0.05, Friedman test. Conclusions Repeated ischemia/reperfusion episodes plus short- term endotoxemia decreased the efficiency of hepatic but not muscle mitochondrial respiration. Mitochondrial dysfunction under these experimental circumstances seems to be organ specific. References S Preisman1, E Segal1, V Glauber1, E Heldenberg1, R Walden1, D Givony2, N Dekel2, L Oren2, E Pewzner2, A Mayevsky3, A Perel1 1Sheba Medical Center, Tel-Hashomer, Rama-Gan, Israel; 2CritiSense Ltd, Givat Shmuel, Israel; 3Bar-Ilan University, Ramat-Gan, Israel Critical Care 2007, 11(Suppl 2):P260 (doi: 10.1186/cc5420) References 1. Porta F, et al.: Crit Care 2006, 10:R118. 2. Rhee P, et al.: Crit Care Med 1997, 25:166-170. Monitoring of the mitochondrial NADH redox state (an indicator of intracellular oxygen levels) together with microcirculatory blood flow (TBF) and with oxygenation (HbO2) could serve as a preferred approach to evaluate tissue O2 balance or viability. We hypothesize that in the presence of reduced oxygen delivery and extraction, blood flow will be redistributed in order to protect the most vital organs by increasing their regional blood flow, while O2 delivery to the less vital organs will diminish. Thus, the NADH redox state of less vital organs could serve as an indicator of overall O2 imbalance as well as an endpoint of resuscitation. We have therefore developed an optical device embedded in a Foley catheter to provide real-time data on the NADH redox state, TBF and HbO2 in critically ill patients. Impact of body mass index on postoperative bleeding in cardiopulmonary bypass Conclusions Lower BMI was associated with higher postoperative bleeding and lower procoagulant factor levels. Introduction Body mass index (BMI) has been described as a risk factor for coronary artery disease, but association with S105 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine Table 1 (abstract P258) Conclusion While increasing DO2,h far exceeded decreasing VO2,h in the setting of hyperdynamic fluid-resuscitated septic shock, hepatic mitochondrial function was significantly impaired compared with control. E Borotto1, D Tüller1, S Krähenbühl2, D Mettler1, J Takala1, S Jakob1 1University Hospital Bern, Switzerland; 2University Hospital Basel, Switzerland Critical Care 2007, 11(Suppl 2):P258 (doi: 10.1186/cc5418) Table 1 (abstract P258) After After End of Baseline bleeding endotoxin experiment MAP (mmHg) 69 (52–70) 36 (30–46) 67 (49–84) 47 (19–109) CI (ml/kg/min) 85 (62–95) 55 (42–76) 95 (78–113) 69 (16–151) PAP (mmHg) 14 (10–17) 12 (9–13) 45 (40–51) 32 (17–38) SvO2 (%) 49 (41–56) 33 (25–37) 54 (47–68) 46 (14–66) PAP, pulmonary artery pressure. P < 0.05, Friedman test. P258 hepatic mitochondrial dysfunction was present in a clinically relevant porcine model of fluid-resuscitated septic shock. hepatic mitochondrial dysfunction was present in a clinically relevant porcine model of fluid-resuscitated septic shock. Methods Anesthetized and ventilated pigs (40 ± 3 kg) were randomly assigned to septic shock by fecal peritonitis (F, n = 3) or control (C, n = 3) after placement of portal/hepatic vein catheters and portal vein and hepatic artery flow probes. F and C received 8 ± 13 ml/kg/hour and 5 ± 7 ml/kg/hour ringer lactate + starch, respectively. The mean arterial pressure (MAP), total liver flow (TLF), hepatic O2 delivery (DO2,h) and hepatic O2 consumption (VO2,h) were recorded at baseline (BL), 12 and 24 hours (ml/kg/min). Activities of mitochondrial respiratory chain enzymes (complex I–IV) were assessed by spectrophotometry in snap- frozen liver samples. Data are presented as the mean ± SD. Methods Anesthetized and ventilated pigs (40 ± 3 kg) were randomly assigned to septic shock by fecal peritonitis (F, n = 3) or control (C, n = 3) after placement of portal/hepatic vein catheters and portal vein and hepatic artery flow probes. F and C received 8 ± 13 ml/kg/hour and 5 ± 7 ml/kg/hour ringer lactate + starch, respectively. The mean arterial pressure (MAP), total liver flow (TLF), hepatic O2 delivery (DO2,h) and hepatic O2 consumption (VO2,h) were recorded at baseline (BL), 12 and 24 hours (ml/kg/min). Activities of mitochondrial respiratory chain enzymes (complex I–IV) were assessed by spectrophotometry in snap- frozen liver samples. Data are presented as the mean ± SD. Cytokines monitored by microdialysis detect rejection earlier than current methods in liver transplantation Cytokines monitored by microdialysis detect rejection earlier than current methods in liver transplantation L Wælgaard, EB Thorgersen, P Line, T Mollnes, T Tonnessen Rikshospitalet, Oslo, Norway Critical Care 2007, 11(Suppl 2):P261 (doi: 10.1186/cc5421) Introduction The outcome of liver transplantation is steadily improving. There is still need for earlier detection of complications such as hepatic artery thrombosis and rejection. In an earlier in vitro study we showed that the CMA microdialysis system with a 100 kDa pore size membrane can be used to measure the selected cytokines and complement. We monitored patients undergoing liver transplantation with microdialysis continuously for a week postoperatively, and analyzed both parameters to detect ischemia, and cytokines and anaphylatoxins to explore whether rejection was detected earlier than with the standard methods. Results During cardiac luxations, the oxygen availability in the sublingual microcirculation decreased (µHbO2 64.2 ± 9.1 to 48.6 ± 8.7%; P < 0.01) while the functional capillary density did not change (15.9 ± 1.1 to 15.6 ± 1.3 mm/mm2; P = 0.65). Although the small vessels (0–20 µm) did not fall out they did show hypoperfusion (Vmax 895 ± 209 to 396 ± 178 µm/s; P < 0.01), whereas in the medium vessels (20–50 µm) there was no significant change in blood velocity (Vmax 751 ± 239 to 596 ± 192 µm/s; P = 0.18) as observed with sidestream dark field imaging and calculated with microvascular analysis software. Methods Twenty patients undergoing 22 liver transplantations were included. Two microdialysis catheter were introduced in the liver and one in subcutaneous tissue. We analyzed metabolic parameters (glucose, pyruvate, glycerol and lactate), and IL-6, IL-8, MCP-1, IP-10, and C5a. Conclusion Alterations in sublingual microcirculation hemo- dynamics reflect the direct effects of obstructive shock and elucidate the microcirculatory autoregulation. Results Fourteen patients had an uneventful course postoperatively, judged clinically and by routine biochemical markers and ultrasound Doppler. These patients had a median lactate starting at 3.5 mM (2 hours after reperfusion) falling to below 2 mM during the first 24 hours, and thereafter staying low. The L/P ratio (a specific measure of ischemia) dropped from about 20 to below 10. These patients had a steady rise in IP-10 from 200 to 3,000 pg/ml, and also a slight raise in IL-6 initially. Case 1. The male patient had a steadily increasing L/P ratio during the 7 days of microdialysis measurements, indicating an insufficient blood supply. P261 Methods During cardiac luxations, in 12 patients reflectance spectrophotometry (O2C®; Lea Medizintechnik, Germany) was used to measure oxygen availability and in 12 other patients sidestream dark field imaging (MicroScan®; MicroVision Medical, The Netherlands) was used to directly visualize the sublingual microcirculatory hemodynamics in a single network of micro- vessels. Microvascular analysis software (MAS®; MicroVision Medical) was used to analyze the vessel density and blood flow. Synchronously, systemic hemodynamics were recorded and the cardiac output was calculated by pulse contour analysis of arterial pressure (PulseCO®; LiDCO, UK) in all patients. P262 These preliminary swine model and human studies confirm the feasibility of collecting information about mitochondrial function from the urethral wall. The main effects of graded hemorrhage started when the blood volume decreased by 30%. At 40% blood loss, minimal levels of TBF and HbO2 were correlated to the maximal NADH levels. The values of the three parameters returned to baseline after retransfusion of the shed blood. Aortic clamping in patients led to a significant decrease in TBF and HbO2 while NADH levels increased. After aortic declamping, the parameters recovered to normal values. Cytokines monitored by microdialysis detect rejection earlier than current methods in liver transplantation He underwent surgery 5 days later and a hepatic artery thrombosis was found. A biopsy was done during the operation showing an acute rejection. There was a significant rise in IP-10 to 13,000 pg/ml 7 days before the diagnosis of rejection. Case 2. The female patient had an acute rejection verified by biopsies on day 10 postoperatively. Her IL-8, IP-10 and C5a increased 10-fold to 100-fold in the liver 3 days earlier than an increase in liver enzymes and 5 days before the rejection was verified by biopsy. Conclusion We have described the normal course of the four cytokines IL-6, IL-8, MCP-1 and IP-10 and complement C5a after liver transplantation, as well as metabolic parameters to detect Microcirculatory hemodynamic alterations during cardiac luxation in off-pump coronary artery bypass grafting surgery Microcirculatory hemodynamic alterations during cardiac luxation in off-pump coronary artery bypass grafting surgery B Atasever1, R Speekenbrink2, J Seyffert2, C Ince3 1Erasmus Medical Center Rotterdam, The Netherlands; 2Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands; 3Academic Medical Center, Amsterdam, The Netherlands Critical Care 2007, 11(Suppl 2):P262 (doi: 10.1186/cc5422) Introduction During luxation of the beating heart in off-pump coronary artery bypass grafting surgery the cardiac output drops and causes hypotension (<60 mmHg). It is expected that this state of obstructive shock is detrimental for adequate perfusion and oxygenation of organ tissue. However, it is unknown whether these luxations cause microcirculatory dysfunction. In this study we have explored the hemodynamics of the sublingual microcirculation during mechanical manipulations of the beating heart. Our preliminary results show that the CritiView may be a useful tool for the detection of O2 imbalance and the development of an emergency metabolic state in nonvital tissues. Reference 1. Mayevsky et al.: SPIE Proc 2006, 6083:OZ1-OZ10. Hepatic mitochondrial dysfunction in fluid-resuscitated porcine septic shock Hepatic mitochondrial dysfunction in fluid-resuscitated porcine septic shock J Wauters1, I Vanhorebeek2, A Dieudonne1, G Van den Berghe1, A Wilmer3 J Wauters1, I Vanhorebeek2, A Dieudonne1, G Van den Berghe1, A Wilmer3 1University Hospital Gasthuisberg, Leuven, Belgium; 2Catholic University of Leuven, Belgium; 3UZ Gasthuisberg, Leuven, Belgium Critical Care 2007, 11(Suppl 2):P259 (doi: 10.1186/cc5419) J Wauters1, I Vanhorebeek2, A Dieudonne1, G Van den Berghe1, A Wilmer3 1University Hospital Gasthuisberg, Leuven, Belgium; 2Catholic University of Leuven, Belgium; 3UZ Gasthuisberg, Leuven, Belgium Critical Care 2007, 11(Suppl 2):P259 (doi: 10.1186/cc5419) 1University Hospital Gasthuisberg, Leuven, Belgium; 2Catholic University of Leuven, Belgium; 3UZ Gasthuisberg, Leuven, Belgium Critical Care 2007, 11(Suppl 2):P259 (doi: 10.1186/cc5419) Background Sepsis-induced multiple organ failure may crucially depend on the development of mitochondrial dysfunction and consequent cellular energetic failure. We investigated whether The CritiView is a computerized optical device that integrates hardware and software in order to provide real-time information of S106 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 tissue viability [1]. A modified three-way Foley catheter that contains a fiberoptic probe connects the CritiView to the mucosal side of the urethral wall. We have used this device in five female pigs that underwent graded hemorrhage, and in four patients who were monitored during aortic abdominal aneurysm operations. ischemia. In two patients with rejection we found a large increase in IP-10, IL-8 and complement split-product C5a in the liver but not in the subcutis 3–5 days before any other parameter of liver injury. P264 Methods Twelve patients were included. Anesthesia consisted of thoracic epidural analgesia, restrictive peroperative fluid therapy (net peroperative fluid balance below 4 l) and early extubation. In the ICU, fluid infusion was adjusted in order to maintain hourly urine production of 0.5 ml/kg. The mean arterial pressure was maintained at or above 60 mmHg with administration of nor- adrenalin if necessary. Microcirculation was visualized in the sublingual tissue with the MicroScan, a sidestream dark field imager. Data were collected at five time points: immediately after induction, after gastric tube reconstruction, directly postoperative, and days 1 and 2 postoperatively. Video data collected with the MicroScan were analysed according to semiquantitative analysis described by Boerma and colleagues [1]. We divided the vessels into three categories: small (5–10 µm), medium (10–15 µm) and large (>15 µm). By dividing the images into four quadrants and categorizing the flow per vessel-size per quadrant, we calculated the microvascular flow index (MFI) Sublingual microcirculation is impaired during cardiopulmonary bypass in cardiac surgery C den Uil1, W Lagrand1, P Spronk2, J Hofland1, C Luthen1, M van der Ent1, R van Thiel1, A Bogers1, M Simoons1 1Erasmus MC, Rotterdam, The Netherlands; 2Gelre Hospitals, Apeldoorn, The Netherlands Critical Care 2007, 11(Suppl 2):P264 (doi: 10.1186/cc5424) Introduction Cardiac surgery patients are at low risk for postoperative complications, but these may involve multiple organ failure with a high mortality rate. These complications may be related to occurrence of organ ischemia and reperfusion during and just after surgery. We investigated whether microcirculatory flow alterations occur during cardiac surgery. Methods We observed 10 consecutive patients who underwent cardiac surgery with cardiopulmonary bypass (CPB). The micro- circulation was studied using sidestream dark field (SDF) imaging. The sublingual capillary flow was estimated using a semi- quantitative microvascular flow index (MFI) in small (diameter 10–25 µm), medium (25–50 µm), and large (50–100 µm) sized microvessels (0 = none, 1 = intermittent, 2 = sluggish, 3 = continuous flow). SDF imaging was performed at least three times per time period (that is, at baseline, after starting CPB and after surgery) in each patient. Data are presented as the median and interquartile range. Muscle microcirculation alterations increase with disease severity in chronic heart failure patients Muscle microcirculation alterations increase with disease severity in chronic heart failure patients V Gerovasili, C Pierakos, S Dimopoulos, E Kaldara, S Kourtidou, S Sarafoglou, M Kravari, J Venetsanakos, G Tzanis, S Nanas National and Kapodestrian University of Athens, Greece Critical Care 2007, 11(Suppl 2):P263 (doi: 10.1186/cc5423) Objective To evaluate skeletal muscle microcirculation by near- infrared spectroscopy (NIRS) in patients with chronic heart failure (CHF). Background Skeletal muscle microcirculation is impaired in patients with CHF, and this impairment seems to correlate with disease severity. Methods We evaluated 49 patients with CHF (mean age: 58 ± 12 years) and 12 healthy volunteers. Of the CHF patients, 14 had S107 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin surgery. Despite maintaining common circulatory parameters during CPB, the nonpulsatile status, hypothermia, and the temporary drop in MAP after starting CPB were associated with decreased sublingual MFI, which normalized after surgery. Further studies should reveal whether these changes are related to outcome. end-stage heart failure (ESCHF) and were undergoing treatment with intermittent inotropic agent infusion during the period of the study protocol. The thenar muscle tissue oxygen saturation (StO2%) was measured noninvasively by NIRS before, during and after 3-minute occlusion of the brachial artery (occlusion technique). Results Patients with ESCHF (n = 14) and CHF (n = 35) presen- ted a significantly lower tissue oxygen saturation (StO2) than healthy subjects (75 ± 6%, 77 ± 8% and 85 ± 5%, P = 0.001 respec- tively). The oxygen consumption rate during the occlusion of the brachial artery differed significantly between patients with ESCHF, CHF and healthy subjects (22.4 ± 9%/min, 29 ± 10%/min and 38.1 ± 11.1%/min, P = 0.001 respectively). The reperfusion rate differed significantly between patients with ESCHF, CHF and healthy subjects (302 ± 136%/min, 393 ± 134%/min and 480 ± 133%/min, P = 0.002 respectively). P265 Sublingual microcirculation is impaired on the first day postoperatively in patients undergoing gastric tube reconstruction J Van Bommel, H Tilanus, J Bakker, D Gommers Erasmus MC, Rotterdam, The Netherlands Critical Care 2007, 11(Suppl 2):P265 (doi: 10.1186/cc5425) Sublingual microcirculation is impaired on the first day postoperatively in patients undergoing gastric tube reconstruction Sublingual microcirculation is impaired on the first day postoperatively in patients undergoing gastric tube reconstruction J Van Bommel, H Tilanus, J Bakker, D Gommers Erasmus MC, Rotterdam, The Netherlands Critical Care 2007, 11(Suppl 2):P265 (doi: 10.1186/cc5425) Introduction Complications of oesophagectomy with gastric tube reconstruction include leakage and stenosis. This can be explained by compromised local perfusion, although it is unclear to which extent local and systemic factors contribute to this process. The aim of this study was to observe the microvascular blood flow in an unaffected, distant tissue during the perioperative period. Conclusions Peripheral muscle microcirculation assessed by NIRS is impaired in CHF patients. The degree of dysfunction is associated with disease severity and is acutely partially reversed with inotropic agent infusion. Changes in sublingual microvascular flow during experimental human endotoxemia Changes in sublingual microvascular flow during experimental human endotoxemia Results Nonsurvivors demonstrated a significantly higher MODS score when compared with survivors (P = 0.004). Norepinephrine requirements were higher in nonsurvivors (P = 0.018). Non- survivors had higher arterial lactate levels (P = 0.046), decreased arterial pH levels (P = 0.001), and decreased arterial PO2 values (P = 0.013) when compared with survivors. A higher oscillation frequency of skin microvasculature at rest (P = 0.033) and after an ischemic stimulus (P = 0.009) was observed in nonsurvivors. No differences were observed in reactive hyperemia response between groups. The flowmotion frequency observed in reactive hyperemia was associated with the severity of the MODS (P = 0.009), and – although not statistically significant – arterial lactate concentration (P = 0.052). R Bemelmans1, A Draisma2, J van der Hoeven2, P Pickkers2, P Spronk1 1Gelre Ziekenhuizen, Apeldoorn, The Netherlands; 2UMCN, Nijmegen, The Netherlands Critical Care 2007, 11(Suppl 2):P268 (doi: 10.1186/cc5428) R Bemelmans1, A Draisma2, J van der Hoeven2, P Pickkers2, P Spronk1 1Gelre Ziekenhuizen, Apeldoorn, The Netherlands; 2UMCN, Nijmegen, The Netherlands Critical Care 2007, 11(Suppl 2):P268 (doi: 10.1186/cc5428) Introduction We examined sublingual microvascular changes in experimental human endotoxemia. Changes in microcirculation and mitochondrial dysfunction appear to be key mechanisms in sepsis, since they can lead to regional mismatch of oxygen supply and demand. Lipopolysaccharide (LPS) can be used to induce endo- toxemia as a model of sepsis, but the effects on microcirculatory perfusion have not been tested before, particularly after tolerance induction during repeated challenges of LPS. Conclusion An increased skin microvascular oscillation frequency during rest and after an ischemic stimulus is associated with increased mortality in patients suffering from MODS. We suggest that the underlying mechanism of the increased flowmotion could be a response of the skin microvasculature to hypoxia or to an impaired oxygen utilization of the skin tissue. Methods Six healthy volunteers received an intravenous injection of 2 ng/kg Escherichia coli LPS to induce endotoxemia on five consecutive days. Microvascular perfusion was sublingually measured using sidestream darkfield imaging just before, and 2 and 4 hours after LPS injection on day 1. All measurements were repeated on day 5 of LPS administration. Sublingual capillary flow was estimated using a semiquantative microvascular flow index (MFI) in small (10–25 µm), medium (25–50 µm) and large-sized (50–100 µm) microvessels (no flow, 0; intermittent flow, 1; sluggish flow, 2; and continuous flow, 3). Effect of intermittent positive pressure ventilation on the skeletal muscle and small intestine microcirculation in rats Effect of intermittent positive pressure ventilation on the skeletal muscle and small intestine microcirculation in rats V Cerny, Z Turek, R Parizkova, P Dostal University Hospital Hradec Kralove, Czech Republic Critical Care 2007, 11(Suppl 2):P267 (doi: 10.1186/cc5427) Introduction Intermittent positive pressure ventilation (IPPV) may be accompanied by alteration of microcirculation [1,2]; however, the effect of IPPV is not mentioned in the interpretation of the results of studies evaluating microcirculation using orthogonal polarization spectral or sidestream dark-field imaging. This study aimed to evaluate the effect of IPPV on microcirculation in the skeleton muscles and in the serosa of the small intestine in rats. Introduction Intermittent positive pressure ventilation (IPPV) may be accompanied by alteration of microcirculation [1,2]; however, the effect of IPPV is not mentioned in the interpretation of the results of studies evaluating microcirculation using orthogonal polarization spectral or sidestream dark-field imaging. This study aimed to evaluate the effect of IPPV on microcirculation in the skeleton muscles and in the serosa of the small intestine in rats. Methods Ten animals were tracheostomized and prepared for microcirculation study; after tissue preparation, five rats were allowed to breath spontaneously (Group SB = spontaneous breathing), and five rats (Group IPPV) were connected to a small animal ventilator (IPPV: FiO2 0.21, respiratory rate 60/min, tidal volume 10 ml/kg, inspiratory time 50% of respiratory cycle, and Results Two hours after the induction of endotoxemia (n = 6), sublingual flow in small (2 (1.7–2.3)), medium-sized (1.5 (1.2–1.9)), and large microvessels (2.5 (1.2–2.7)) did not differ from baseline values (2.3 (1.5–2.8), 2.3 (1.4–2.5), and 2.3 (1.3–2.5), respectively, all P = not significant). Microvascular flow did not change in the subsequent 2 hours. In addition, no difference in microvascular flow could be demonstrated between timepoints on day 1 and day 5 of intermittent endotoxemia. Conclusion In this small pilot study in experimental human endotoxemia, no significant effect of LPS administration on microcirculatory perfusion could be observed, nor any sign of tolerance. Further studies should reveal whether microvascular impairment does not occur in early human experimental Results Two hours after the induction of endotoxemia (n = 6), sublingual flow in small (2 (1.7–2.3)), medium-sized (1.5 (1.2–1.9)), and large microvessels (2.5 (1.2–2.7)) did not differ from baseline values (2.3 (1.5–2.8), 2.3 (1.4–2.5), and 2.3 (1.3–2.5), respectively, all P = not significant). Microvascular flow did not change in the subsequent 2 hours. References 1. Saner FH, et al.: Eur J Anaesth 2006, 23:766-771. 2. De Backer D, et al.: Am Heart J 2004, 147:91-99. 1. Saner FH, et al.: Eur J Anaesth 2006, 23:766-771. 2. De Backer D, et al.: Am Heart J 2004, 147:91-99. 1. Saner FH, et al.: Eur J Anaesth 2006, 23:766-771. 2. De Backer D, et al.: Am Heart J 2004, 147:91-99. 1. Saner FH, et al.: Eur J Anaesth 2006, 23:766-771. 2. De Backer D, et al.: Am Heart J 2004, 147:91-99. Changes in sublingual microvascular flow during experimental human endotoxemia Changes were evaluated with the paired Wilcoxon test and sign test. P < 0.05 was judged to indicate a significant difference. Values are expressed as the median (P25–P75). P266 2 cmH2O PEEP). Sidestream dark-field images were obtained from the quadriceps femoris muscle (QFM) and serosa surface of the ileum. The arterial blood pressure and rectal temperature were also recorded. The functional capillary density (FCD) and small and medium vessels rate were analysed offline using AVA V1.0 soft- ware (AMC, University of Amsterdam, The Netherlands), P ≤0.05. Results The FCD was decreased significantly in QFM in rats with IPPV with respect to Group SB (184 ± 27 resp. 197 ± 61 cm/cm2), but the FCD of the intestinal serosa was not affected by IPPV (265 ± 46 resp. 267 ± 25 cm/cm2). There were no differences in mean blood pressure and temperature between groups (128 ± 7 Torr and 36.6 ± 0.1°C in Group SB, or 128 ± 10 Torr and 36.5 ± 0.1°C in Group IPPV). Figure 1 (abstract P265) Sublingual microvascular perfusion. Results The MFI decreased in all sizes of microvessels <15 minutes after starting CPB in comparison with baseline (P < 0.05, Table 1). After starting CPB, the mean arterial pressure (MAP) was lower (61 mmHg (53–65 mmHg)) than at baseline (100 mmHg (92–118 mmHg); P = 0.01). After return to the ICU, the MFI increased (P < 0.05) and returned to baseline values in all microvessels. Sublingual microvascular perfusion. Conclusions SDF imaging can be used as a bedside tool to evaluate sublingual microcirculatory changes during cardiac Table 1 (abstract P264) Baseline CPB Postsurgery MFI small 3 (3–3) 2 (0.4–3) 3 (2.9–3) MFI medium 3 (2.2–3) 1.9 (0.8–3) 3 (2.9–3) MFI large 3 (3–3) 2.4 (0.9–3) 3 (3–3) MAP 100 (92–118) 61 (53–65) 79 (71–85) Conclusion The sublingual microcirculation is decreased on the first day postoperatively in patients undergoing gastric tube reconstruction. 1. Boerma EC, Mathura KR, van der Voort PH, et al.: Quantify- ing bedside-derived imaging of microcirculatory abnor- malities in septic patients: a prospective validation study. Crit Care 2005, 9:R601-R606. S108 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Oscillation frequency of skin microvascular blood flow is associated with mortality in critically ill patients Oscillation frequency of skin microvascular blood flow is associated with mortality in critically ill patients Oscillation frequency of skin microvascular blood flow is associated with mortality in critically ill patients H Knotzer1, S Maier1, W Pajk1, M Dünser2, W Hasibeder3 1Innsbruck Medical University, Innsbruck, Austria; 2University Hospital Bern, Switzerland; 3Krankenhaus der Barmherzigen Schwestern Ried, Ried, Austria Critical Care 2007, 11(Suppl 2):P266 (doi: 10.1186/cc5426) Introduction Microcirculatory dysfunction has been hypothesized to play a key role in the pathophysiology of multiple organ failure, and consequently to patient outcome. The objective of the present study was to investigate differences in reactive hyperemia response and oscillation frequencies in survivors and nonsurvivors of patients with multiple organ dysfunction syndrome (MODS). Introduction Microcirculatory dysfunction has been hypothesized to play a key role in the pathophysiology of multiple organ failure, and consequently to patient outcome. The objective of the present study was to investigate differences in reactive hyperemia response and oscillation frequencies in survivors and nonsurvivors of patients with multiple organ dysfunction syndrome (MODS). Conclusion The use of IPPV should be taken into account in the interpretation of the studies examining the changes in microcirculation in rats. Methods Twenty-nine patients (15 survivors; 14 nonsurvivors) with two or more organ failures were eligible for study entry. All patients were hemodynamically stabilized, and demographic and clinical data were recorded. A laser Doppler flowmeter was used to measure the cutaneous microcirculatory response. Reactive hyperemia and oscillatory changes in the Doppler signal were measured during 3 minutes before and after a 5-minute period of forearm ischemia during hyperemia. Acknowledgement Research project MZO 00179906. References Acknowledgement Research project MZO 00179906. References Reference 1. Boekstegers P, Weidenhofer S, Kapsner T, Werdan K: Skele- tal muscle partial pressure of oxygen in patients with sepsis. Crit Care Med 1994, 22:640-650. 1. Boekstegers P, Weidenhofer S, Kapsner T, Werdan K: Skele- tal muscle partial pressure of oxygen in patients with sepsis. Crit Care Med 1994, 22:640-650. 1. Boekstegers P, Weidenhofer S, Kapsner T, Werdan K: Skele- tal muscle partial pressure of oxygen in patients with sepsis. Crit Care Med 1994, 22:640-650. Effect of intermittent positive pressure ventilation on the skeletal muscle and small intestine microcirculation in rats In addition, no difference in microvascular flow could be demonstrated between timepoints on day 1 and day 5 of intermittent endotoxemia. Methods Ten animals were tracheostomized and prepared for microcirculation study; after tissue preparation, five rats were allowed to breath spontaneously (Group SB = spontaneous breathing), and five rats (Group IPPV) were connected to a small animal ventilator (IPPV: FiO2 0.21, respiratory rate 60/min, tidal volume 10 ml/kg, inspiratory time 50% of respiratory cycle, and Conclusion In this small pilot study in experimental human endotoxemia, no significant effect of LPS administration on microcirculatory perfusion could be observed, nor any sign of tolerance. Further studies should reveal whether microvascular impairment does not occur in early human experimental S109 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine Figure 2 (abstract P269) Figure 2 (abstract P269) endotoxemia, or that sidestream darkfield imaging is not useful in this specific setting. endotoxemia, or that sidestream darkfield imaging is not useful in this specific setting. Occurrence and functional consequences of shunting of the microcirculation after mesenteric ischemia Occurrence and functional consequences of shunting of the microcirculation after mesenteric ischemia M Lauterbach, G Horstick, N Plum, L Weilemann, T Münzel, O Kempski University Hospital Mainz, Germany Critical Care 2007, 11(Suppl 2):P270 (doi: 10.1186/cc5430) Results In the control group, all parameters were not changed during the observation period of 400 minutes. In the experimental group, the mean arterial pressure (MAP) remained fairly stable until 300 minutes after injection of LPS, and the MAP gradually decreased subsequently. While the MAP was maintained, the PtO2 gradually decreased linearly (Figure 1). TL increased with time linearly. Meanwhile, BL did not change from 150 to 250 minutes; after 300 minutes it increased abruptly in the experimental group (Figure 2). Shunting of the microcirculation contributes to the pathology of sepsis and septic shock. In this study, we hypothesize that shunting of the microcirculation occurs after superior mesenteric artery (SMA) ischemia (occlusion) and reperfusion, and we explore functional consequences using intravital microscopy. Conclusions In our experimental endotoxemia model it has been shown that partial pressure of oxygen in subcutaneous tissue decreased even if systemic blood pressure was maintained. Boekstegers and colleagues [1] revealed that mean skeletal q g py Spontaneously breathing animals (rats) (n = 30) underwent occlusion of the SMA for 0 (controls), 30 or 60 minutes followed by reperfusion (4 hours) with normal saline. Leukocyte–endothelial interactions in mesenteric venules were quantified in an exteriorized ileal loop using intravital microscopy. Abdominal blood flow was recorded continuously, and arterial blood gases were analyzed at intervals. Continuous SMA blood flow measurements were performed in comparable groups without exteriorizing an ileal loop. Adherent leukocytes increased shortly after reperfusion in ischemia groups, and plateaued in these groups. The centerline velocity and shear rate in the recorded venules were significantly reduced after reperfusion down to low-flow/no-flow in animals undergoing 60 minutes of mesenteric artery occlusion compared with animals with 30 minutes occlusion and controls, whereas perfusion of the SMA and ileal vessels persisted. The microcirculatory changes in animals with 60 minutes occlusion were accompanied by progressive metabolic acidosis, substantially larger volumes of intravenous fluids needed to support arterial blood pressure and significantly reduced survival (30%). In the groups with continuous SMA blood flow measurements, SMA blood flow increased in Spontaneously breathing animals (rats) (n = 30) underwent occlusion of the SMA for 0 (controls), 30 or 60 minutes followed by reperfusion (4 hours) with normal saline. Occurrence and functional consequences of shunting of the microcirculation after mesenteric ischemia Leukocyte–endothelial interactions in mesenteric venules were quantified in an exteriorized ileal loop using intravital microscopy. Abdominal blood flow was recorded continuously, and arterial blood gases were analyzed at intervals. Continuous SMA blood flow measurements were performed in comparable groups without exteriorizing an ileal loop. 0 Figure 1 (abstract P269) P269 Biochemical changes detected by microdialysis in subcutaneous tissue during experimental endotoxemia in rat H Ohashi, Y Taira, Y Masui, K Morisawa, H Takahashi, Y Fujinawa, T Kashimura, K Akashi St Marianna University School of Medicine, Kawasaki, Japan Critical Care 2007, 11(Suppl 2):P269 (doi: 10.1186/cc5429) Introduction Shock is defined currently as tissue oxygen metabolic disorders. It is most important to understand oxygen metabolic disorders in individual tissue. Microdialysis allows the deter- mination of the metabolic condition in regional tissue and it appears ideal to determine the regional metabolic tissue conditions during endotoxemia. muscle PO2 was increased in patients with sepsis compared with patients with limited infection. We obtained conflicting results to those of Boekstegers and colleagues. The reason for this is unknown. BL abruptly increased during 50–150 minutes, probably from abnormal metabolism induced by LPS in whole-body organs. It is considered that BL did not show a rise during 150–250 minutes due to metabolization of lactate in liver and muscle. TL, which is insusceptible of lactate metabolism by other organs, may reflect abnormality of tissue metabolism precisely. Objective This study was designed to assess the regional metabolic tissue conditions on markers of tissue metabolism (lactate in regional tissue: tissue lactate (TL)) and tissue partial oxygen pressure (PtO2) during severe endotoxemia and to compare them with variables determined by standard monitoring (hemodynamics, blood gas analysis, blood lactate (BL)). Materials and methods Male Wister rats (body weight 270–300 g) were used for this study. The rats in the control group (n = 6) were injected with saline of 2 ml intraperitoneally, and the rats in the experimental group (n = 6) were treated with intraperitoneal injection of lipopolysaccharide (LPS) of 40 mg/kg. The hemo- dynamic parameters, arterial blood gas analysis, BL and PtO2 were measured in both groups. TL and pyruvate in subcutaneous tissue were measured using microdialysis. These parameters were measured every 50 minutes until 400 minutes after LPS was administered. P271 Changes in tissue oxygen saturation reflect changes in targeted oxygen delivery in postoperatively optimised patients M Hamilton, M Canete, M Cecconi, N Al-subaie, A Vercuil, J Fawcett, D Dawson, A Rhodes St George’s Hospital, London, UK Critical Care 2007, 11(Suppl 2):P271 (doi: 10.1186/cc5431) use of noninvasive tissue oxygenation devices in surgical optimisation. p Reference Introduction Targeting oxygen delivery in the postoperative period has been shown to reduce hospital length of stay and complica- tions [1]. Using a near-infrared spectroscopy device such as the Inspectra™ 325 allows the measurement of tissue oxygen satura- tion (STO2) noninvasively as well as a rudimentary measure of blood flow beneath the probe. It is plausible, then, that changes in oxygen delivery (DO2) during postoperative optimisation may be reflected in changes in STO2 and provide a noninvasive surrogate of DO2. 1. Pearse et al.: Early goal-directed therapy after major surgery reduces complications and duration of hospital stay. Crit Care 2005, 9:R687-R693. Figure 1 (abstract P269) Figure 1 (abstract P269) Adherent leukocytes increased shortly after reperfusion in ischemia groups, and plateaued in these groups. The centerline velocity and shear rate in the recorded venules were significantly reduced after reperfusion down to low-flow/no-flow in animals undergoing 60 minutes of mesenteric artery occlusion compared with animals with 30 minutes occlusion and controls, whereas perfusion of the SMA and ileal vessels persisted. The microcirculatory changes in animals with 60 minutes occlusion were accompanied by progressive metabolic acidosis, substantially larger volumes of intravenous fluids needed to support arterial blood pressure and significantly reduced survival (30%). In the groups with continuous SMA blood flow measurements, SMA blood flow increased in S110 Available online http://ccforum.com/supplements/11/S2 use of noninvasive tissue oxygenation devices in surgical optimisation. Reference 1. Pearse et al.: Early goal-directed therapy after major surgery reduces complications and duration of hospital stay. Crit Care 2005, 9:R687-R693. P272 General anesthesia impairs muscle microvascular compliance Figure 2 (abstract P271) Figure 2 (abstract P271) Figure 2 (abstract P271) Figure 2 (abstract P271) Figure 2 (abstract P271) relation to abdominal blood flow after reperfusion in animals with 60 minutes occlusion, and remained constant in animals under- going 30 minutes occlusion and controls. Survival was 80% in animals with 60 minutes occlusion without an exteriorized ileal loop. SMA occlusion for 60 minutes and subsequent reperfusion causes perfusion abnormalities in the mesenteric microcirculation as often seen in sepsis and septic shock with increased microcirculation shunting, progressive metabolic acidosis and increased mortality. To detect these significant changes requires prolonged observation periods and might help to find new treatments to improve the poor prognosis of mesenteric ischemia. P272 General anesthesia impairs muscle microvascular compliance General anesthesia impairs muscle microvascular compliance General anesthesia impairs muscle microvascular compliance M Boezi, S Palmisani, F Troisi, A Marcelli, R De Blasi ‘La Sapienza University’, 2nd Faculty of Medicine, Azienda Ospedaliera Sant’Andrea, Rome, Italy Critical Care 2007, 11(Suppl 2):P272 (doi: 10.1186/cc5432) 2 Methods All adult patients admitted to the ICU after surgery who underwent protocolised haemodynamic optimisation were included. All patients had STO2 recorded over the thenar eminence using an Inspectra™ 325 for the first 8 hours of their stay. Introduction Drugs used to induce and maintain general anesthesia have deep effects on the cardiovascular system. To our knowledge there are no studies investigating microvascular compliance during general anesthesia with a noninvasive approach based on near-infrared spectroscopy (NIRS) technology. Results We found a significant correlation between the changes in STO2 and oxygen delivery index (DO2I) over the first 8 hours of intensive care stay (n = 40, correlation coefficient of 0.947, P = 0.0001, Figure 1). We classified patients who achieved DO2I > 600 ml/min/m2 as responders. These responders had higher STO2 values by 3 hours of optimisation, a change that remained significant throughout the duration of the study (Figure 2). Methods We randomized 36 healthy subjects undergoing maxillo- facial surgery to receive general anesthesia with a sevofluorane– remifentanil (Group S) or a propofol–remifentanil association (Group P). We collected noninvasive measures of hemoglobin concentration from the gastrocnemius muscle of the subjects using a NIRS device (NIMO, NIROX srl, Italy), which performs quantitative assessments of the [HbO2] and [Hb] exploiting precise absorption measurements close to the absorption peak of the water. Data were collected during a series of venous occlusions at different cuff pressures, before and after 30 minutes from induction of general anesthesia. The muscle blood volume and microvascular compliance were obtained with a process previously described elsewhere [1]. Data were analyzed with a one-way analysis of variance test. Conclusion Changes in STO2 during postoperative optimisation appear to mirror changes in DO2I and may allow more widespread Conclusion Changes in STO2 during postoperative optimisation appear to mirror changes in DO2I and may allow more widespread Figure 1 (abstract P271) Figure 1 (abstract P271) Results Demographic data of the 36 subjects were similar in both Groups S and P. General anesthesia reduced the heart rate and mean arterial pressure and increased the total muscle blood volume in both groups (Group S: from 2.4 ± 0.9 to 3.2 ± 1.2 ml/ 100 ml; Group P: from 2.4 ± 1.2 to 3.5 ± 1.8 ml/100 ml; P < 0.05). During general anesthesia, despite no differences in muscle blood volume between the two groups, sevofluorane– remifentanil significantly decreased microvascular compliance (from 0.15 ± 0.08 to 0.09 ± 0.04 ml/mmHg/100 ml; P = 0.001) whereas propofol–remifentanil did not (from 0.15 ± 0.08 to 0.16 ± 0.11 ml/mmHg/100 ml; P = 0.39). S111 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Conclusion General anesthesia affects the microvascular bed of skeletal muscle. An association between opioid and ipnotic agents increases the muscle blood volume, whereas microvascular com- pliance is reduced only by the sevofluorane–remifentanil association. spectroscopy is noninvasive and in the emergency setting is a rapidly appliable method for measuring StO2. spectroscopy is noninvasive and in the emergency setting is a rapidly appliable method for measuring StO2. Methods In a prospective observational study we included 340 consecutive medical emergency room patients. On admission, StO2 and the rate of tissue deoxygenation during stagnant ischemia were measured by the near-infrared spectroscopy method (InSpectra tissue spectrometer; Hutchinson Technology Inc., The Netherlands) and correlated with clinical signs of shock, lactate and outcome. Methods In a prospective observational study we included 340 consecutive medical emergency room patients. On admission, StO2 and the rate of tissue deoxygenation during stagnant ischemia were measured by the near-infrared spectroscopy method (InSpectra tissue spectrometer; Hutchinson Technology Inc., The Netherlands) and correlated with clinical signs of shock, lactate and outcome. 1. De Blasi RA, Palmisani S, Alampi D, et al.: Microvascular dysfunction and skeletal muscle oxygenation assessed by phase modulation near-infrared spectroscopy in patients with septic shock. Intensive Care Med 2005, 31:1661- 1668. Results Three hundred and forty patients were included. Of 137 patients admitted, 16 (11.7%) were admitted to the ICU and 14 (10.2%) died in the hospital. The StO2 was higher in patients who were not admitted compared with patients with LOS > 7 days (80.2 ± 8.7% vs 76.9 ± 9.2%, P = 0.009). P274 Introduction Near-infrared spectroscopy (NIRS) noninvasively monitors muscle tissue oxygen saturation (StO2). It may provide a continuous measurement to identify occult hypoperfusion, guide resuscitation, and predict the development of multiple organ dysfunction (MOD) after severe trauma. We evaluated the correlation between initial StO2 and the development of MOD in multitrauma patients. Figure 1 (abstract P271) Tissue deoxygenation was faster (16.7 ± 7.0%/min vs 12.9 ± 5.6%/min, P = 0.014) in survivors. Tissue deoxygenation was slower in the group of patients with clinical signs of shock compared with all patients (11.8 ± 6.0%/min vs 16.5 ± 7.0%/min, P < 0,05). Age, lactate and rate of tissue deoxygenation but not StO2 were significant predictors of death (Table 1). There was weak but significant correlation between StO2 and age (P < 0.0001, r = –0.28), StO2 and lactate (P = 0.035, r = –0.12) and StO2 and systolic blood pressure (P < 0.0001, r = 0.26). P275 Near-infrared spectroscopy during resuscitation of trauma patients predicts development of multiple organ dysfunction: a prospective cohort study Conclusions Exact numerical values of StO2 are not equivalent to those of SvO2. However, for clinical purpose, StO2 values could be used for fast noninvasive SvO2 estimation; and the trend of StO2 may be substituted for the trend of SvO2 in severe left heart failure without additional severe sepsis or septic shock. B Nicks, K Hill, M Chang, W Bozeman Wake Forest University Health Sciences, Winston-Salem, NC, USA Critical Care 2007, 11(Suppl 2):P275 (doi: 10.1186/cc5435) Skeletal muscle oxygen saturation estimates mixed venous oxygen saturation in patients with severe left heart failure Skeletal muscle oxygen saturation estimates mixed venous oxygen saturation in patients with severe left heart failure M Podbregar, H Mozina University Medical Center Ljubljana, Slovenia Critical Care 2007, 11(Suppl 2):P273 (doi: 10.1186/cc5433) M Podbregar, H Mozina University Medical Center Ljubljana, Slovenia Critical Care 2007, 11(Suppl 2):P273 (doi: 10.1186/cc5433) Critical Care 2007, 11(Suppl 2):P273 (doi: 10.1186 Introduction Low cardiac output states, such as left heart failure, are characterized by a preserved oxygen extraction ratio compared with severe sepsis. Near-infrared spectroscopy (NIRS) allows noninvasive estimation of skeletal muscle tissue oxygenation (StO2). The aim of study was to determine relationship between StO2 and mixed venous oxygen saturation (SvO2) in patients with severe left heart failure with or without additional severe sepsis or septic shock. Table 1 (abstract P274) Predictors of survival Predictor Odds ratio P value Age 1.083 0.004 Lactate 1.798 <0.001 Deoxygenation rate 0.895 0.046 Methods Sixty-five patients with severe left heart failure due to primary heart disease were divided into two groups: Group A were patients without (n = 24) and Group B were patients with (n = 41) additional severe sepsis/septic shock. The thenar muscle StO2 was measured using NIRS. Results In Group A StO2 was lower compared with Group B and healthy volunteers (58 ± 13% vs 90 ± 7% vs 84 ± 4%, P < 0.001). StO2 was higher in Group B compared with healthy volunteers (P = 0.02). In Group A StO2 correlated with SvO2 (r = 0.689, P = 0.002), and StO2 overestimated SvO2 (bias: –2.3%, precision: 4.6%). In Group A changes of StO2 correlated to changes of SvO2 (r = 0.836, P < 0.001; ∆SvO2 = 0.84 x ∆StO2 – 0.67). In Group B important disagreement between these variables was present. Plasma lactate concentrations negatively correlated with StO2 values only in group A (r = –0.522, P = 0.009; lactate = –0.104 x StO2 + 10.25). Conclusions StO2 and the rate of tissue deoxygenation during stagnant ischemia are promising additional variables, which can be measured rapidly and noninvasively in the emergency room setting. The rate of deoxygenation rather than StO2 may be helpful for early detection of patients with inadequate tissue perfusion and worse prognosis. Tissue oxygen saturation and the rate of tissue deoxygenation during stagnant ischemia in the medical emergency department M Meþnar, R Pareþnik, G Voga General Hospital Celje, Slovenia Critical Care 2007, 11(Suppl 2):P274 (doi: 10.1186/cc5434) P276 Setting A 16-bed medical–surgical ICU. Buccal visible light spectroscopy and laser Doppler flowmetry: reliability analysis V Gath, Y Sakr, S Klinzing, T Simon, K Reinhart, G Marx Friedrich-Schiller-University Hospital, Jena, Germany Critical Care 2007, 11(Suppl 2):P76 (doi: 10.1186/cc5436) Buccal visible light spectroscopy and laser Doppler flowmetry: reliability analysis Materials and methods This study began about 2 years ago, and the CVP of 41 patients in our ICU were evaluated and compared. Each one of those 41 patients had a CVC in two different locations, one placed in the internal jugular or subclavian veins, and a second in a femoral vein. Simultaneous measurements of CVP were undertaken by two different operators, with a pressure transducer zero referenced at the mid-chest. Standard CVCs with similar features (20 cm length) were used. The patients with an intra-abdominal pressure (IAP) > 15 mmHg were excluded. The IAP was previously evaluated in all patients, using the method described by Sugrue and Hillman. A linear correlation analysis was performed, considering significance P < 0.05 and a correlation coefficient > 0.85. V Gath, Y Sakr, S Klinzing, T Simon, K Reinhart, G Marx Friedrich-Schiller-University Hospital, Jena, Germany Critical Care 2007, 11(Suppl 2):P76 (doi: 10.1186/cc5436) Background There are insatiable demands for new technologies to advance basic biological investigation at the microcirculatory level. Oxygen to see (O2C)® is a newly developed system that combines laser Doppler flow (LDF) and visible light spectroscopy (VLS) technology. The aim of our study was to assess the reliability of O2C® measurements applied to the buccal mucosa and to the thenar eminence in healthy volunteers. Results Forty-one patients were studied, and four patients were excluded due to an IAP > 15 mmHg. The mean age was 63.7 ± 16.2 years, the ICU stay was 10.4 ± 3.5 days, the APACHE II score was 27.8 ± 6.7, and SAPS II was 55.8 ± 11.2. The mean CVP measured with jugular/subclavian access was 11.3 ± 4.5 mmHg, and in the femoral access was 11.8 ± 4.4 mmHg. The linear corre- lation between those measurements was 0.96, and P < 0.007. Methods Microcirculatory hemoglobin oxygen saturation (µHbO2, %) and blood flow (flow, AU) were measured using an O2C® (Lea Medizintechnik GmbH, Giessen, Germany) probe applied to the buccal mucosa and to the thenar eminence. P277 study was the association between StO2 and the development of MOD within the first 24 hours based on a MOD score of 6 or greater. Clinicians were blinded from the StO2 values. Results Over a 14-month period, 78 patients were enrolled. Of the 78 patients, 26 (33.3%) developed MOD within the first 24 hours. The MOD patients had mean (SD) initial StO2 values of 53.3 (±10.3), significantly lower than those of non-MOD patients (61.1 (±10.0); P = 0.002). The MOD patient mean shock index of 0.92 (±0.28) was also significantly higher than those of non-MODS patients (0.73 (±0.19); P = 0.0007). Lactate values were not significantly different. study was the association between StO2 and the development of MOD within the first 24 hours based on a MOD score of 6 or greater. Clinicians were blinded from the StO2 values. study was the association between StO2 and the development of MOD within the first 24 hours based on a MOD score of 6 or greater. Clinicians were blinded from the StO2 values. P277 Central venous pressure in a femoral access: a true evaluation? Central venous pressure in a femoral access: a true evaluation? Results Over a 14-month period, 78 patients were enrolled. Of the 78 patients, 26 (33.3%) developed MOD within the first 24 hours. The MOD patients had mean (SD) initial StO2 values of 53.3 (±10.3), significantly lower than those of non-MOD patients (61.1 (±10.0); P = 0.002). The MOD patient mean shock index of 0.92 (±0.28) was also significantly higher than those of non-MODS patients (0.73 (±0.19); P = 0.0007). Lactate values were not significantly different. N Caramelo1, P Gonçalves1, A Paisana2, B Silva2, C Dias2, S Severino2, P Henriques2, D Marcelino2, D Marum2, D Fernandes2 1Hospital Júlio de Matos, Lisbon, Portugal; 2Hospital Curry Cabral, Lisbon, Portugal Critical Care 2007, 11(Suppl 2):P277 (doi: 10.1186/cc5437) Introduction In patients with bad vascular access, the evaluation of central venous pressure (CVP) obtained in a femoral vein could be an alternative to the evaluation in central venous catheters (CVCs) located in internal jugular or subclavian veins. Conclusions Noninvasive, continuous StO2 NIRS on initial arrival in the TC/ED correlates with the shock index and with the development of MOD. Objective To compare CVP measurement obtained in two different locations (jugular or subclavian veins and femoral veins). M Meþnar, R Pareþnik, G Voga General Hospital Celje, Slovenia Critical Care 2007, 11(Suppl 2):P274 (doi: 10.1186/cc5434) Methods Patients presenting to our urban, academic, Level I Trauma Center/Emergency Department (TC/ED) and meeting standardized trauma-team activation criteria were enrolled. NIRS monitoring with collection of StO2 at the thenar eminence was initiated immediately on arrival at the ED and continued up to 24 hours for those admitted to the trauma ICU. Standardized resuscitation assessment laboratory measures and clinical evalua- tion tools were collected. The primary outcome in this prospective Hypothesis Tissue oxygen saturation (StO2) and the rate of tissue deoxygenation during stagnant ischemia can early and reliably detect inadequate tissue oxygenation and assess prognosis in medical emergency room patients. Hypothesis Tissue oxygen saturation (StO2) and the rate of tissue deoxygenation during stagnant ischemia can early and reliably detect inadequate tissue oxygenation and assess prognosis in medical emergency room patients. Introduction Early recognition of patients with inadequate tissue oxygenation facilitates early diagnostic evaluation and treatment that was correlated with improved outcome. Near-infrared S112 Available online http://ccforum.com/supplements/11/S2 P276 Measurements were obtained simultaneously at two depths, superficial (2 mm) and deep (6 mm), every 2 seconds for 5 minutes and were recorded for later analysis. The procedure was repeated on another occasion at least 1 week apart. Conclusion The CVP can be accurately measured in a femoral vein, using standard CVC, in patients with an IAP < 15 mmHg. Results We studied 20 healthy subjects; 10 males and 10 females (mean age = 38 ± 18 years, range 21–74 years). Both µHbO2 and flow measurements were consistently higher when measured from the deep tissue layers (6 mm) than those measured from the superficial layers, regardless of the site of measurement. Buccal mucosal µHbO2 ranged from 78% to 96% and varied only minimally (CV: 4–7.5%), whereas there was a marked variability in flow measurements (CV: 29–63.9%). The reproducibility of buccal mucosal µHbO2 and flow measurements were moderate to good (that is, intra-individual reliability, ICC: range 0.7–0.87, P < 0.05). However, only measurements from the superficial mucosal layers showed a moderate to good degree of inter-individual agreement (that is, inter-individual reliability, ICC: range 0.68–85, P < 0.001). LDF and VLS values measured on the thenar eminence were highly variable, were not reproducible, and the inter-individual agreement was poor. Table 1 (abstract P280) Methods We tested both the capability of FEER to differentiate states of pulseless electrical activity, and its feasibility in the out-of- hospital setting using mobile, battery-powered ultrasound systems. Trained emergency physicians (EP) applied FEER to assessing basic ventricular function by ‘eye-balling’ in less than 10 seconds in prehospital cardiac arrest victims who were being resuscitated. True pulseless electrical activity (PEA) was defined according to the ERC as ‘clinical absence of cardiac output despite electrical activity’. In contrast, any PEA was classified as a ‘pseudo-PEA’ when cardiac output was visualized by echocardiography. Conclusion We conclude that TTE is feasible in a noncoronary ICU, most parameters being obtained. A routine utilization of TTE detected 53 (7.5%) patients with severe unsuspected diseases. Results Seventy-eight CPR cases (age 66 ± 19 years) were included. On arrival of the EP on the scene, a true PEA was suspected in 31/78 cases. However, in 20/31 PEA cases cardiac wall movement was detected (pseudo-PEA) and correctable causes such as pericardial tamponade (four cases), poor ventricular function (14 cases) and hypovolemia (two cases) were treated. Fourteen out of 20 pseudo-PEA cases survived to hospital admission. In 11/30 PEA cases, no cardiac wall movement was visible (true PEA). All such patients died on the scene. FEER- based changes in therapy were induced in 25/31 cases. The effectiveness of transthoracic echocardiography as a screening examination in a noncoronary intensive care unit The effectiveness of transthoracic echocardiography as a screening examination in a noncoronary intensive care unit P Marcelino1, S Marum1, A Fernandes1, M Lopes2, L Mourao1 1Hospital Curry Cabral, Lisbon, Portugal; 2Lisbon Faculty of Medicine, Lisbon, Portugal Critical Care 2007, 11(Suppl 2):P280 (doi: 10.1186/cc5440) Table 1 (abstract P278) Variable OR (95% CI) P APACHE III score (/10) 1.2 (1–1.4) 0.017 E/E′ (/10) 1.3 (0.6–2.8) 0.5 LV end diastolic volume (/100 ml) 2.0 (1.2–3.3) 0.0059 LV end systolic volume (/100 ml) 2.2 (1.3–3.8) 0.0047 Introduction The authors tested the feasibility of transthoracic echocardiography (TTE) as a routine technique in a medical/ surgical ICU. Methods The study was carried out in a 16-bed noncoronary ICU during 18 months. For this purpose, a TTE was performed within the first 24 hours of admission. The issues addressed were: data acquisition possibilities, quantification of selected echocardio- graphic parameters (cardiac chamber dimensions, left ventricular function, cardiac output, and Doppler examination), detection of any structural echocardiographic alteration, as well as new severe conditions. Conclusion In this cohort of critically ill patients, increased echocardiographic LV end systolic volume, but not filling pressure, is a highly significant predictor of mortality that adds incremental value to APACHE III prediction. P279 Results In this study 704 consecutive patients were enrolled, with a mean age of 61.5 ± 17.5 years, an ICU stay of 10.6 ± 17.1 days, APACHE II score of 22.6 ± 8.9, and SAPS II of 52.7 ± 20.4. In four patients TTE could not be performed. The data are presented in Table 1. At least an echocardiographic alteration was detected in 234 (33%) patients. The most common alterations were left atrial enlargement (n = 163), and left ventricular dysfunction (n = 132). Patients with these alterations were older (66 ± 16.5 vs 58.1 ± 17.4 years, P < 0.001), presented a higher APACHE II score (24.4 ± 8.7 vs 21.1 ± 8.9, P < 0.001) and a higher mortality (40.1 vs 25.4%, P < 0.001). Severe previously unknown echocardiographic diagnoses were detected in 53 (7.5%) patients. The most frequent condition was severe left ventricular dysfunction. By multivariate logistic regression analysis, TTE parameters did not correlate with mortality or ICU stay. Mortality was related to ICU stay (CI 1.0–1.019, P < 0.001). Left ventricular volumes but not filling pressure are determinants of mortality in critically ill patients D Sturgess, T Marwick, C Joyce, M Jones, B Venkatesh University of Queensland, Brisbane, Australia Critical Care 2007, 11(Suppl 2):P278 (doi: 10.1186/cc5438) Introduction Transthoracic echocardiography (TTE) is gaining acceptance as a powerful diagnostic tool in critical illness. It can assess left ventricular (LV) volumes, as well as indices of ventri- cular filling pressure (including the ratio of mitral E velocity/mitral annular velocity [E/E′]). TTE evidence of raised filling pressure is associated with mortality following myocardial infarction but its prognostic value in critical illness is undefined. The aim of this study was to evaluate the prognostic significance of echo- cardiographic LV volumes and filling pressure in the critically ill. Conclusion O2C® provides reliable measurement of buccal µHbO2 and microvascular flow. Skin measurements on the thenar eminence are highly variable and unreliable. Methods A consecutive group of 94 patients (66 males, mean ± SD age 61 ± 15 years) who had standard TTE supplemented by measurement of E/E′ in a tertiary referral ICU were enrolled. TTE was performed 5 ± 6 days after ICU admission. Severity of critical illness was assessed using APACHE III. Cox proportional hazards regression analysis was based on 28-day mortality from the date of echo with survivors censored on hospital discharge. Results The mean APACHE III score was 72 ± 25. Hospital mortality was 33% (n = 31). Table 1 summarises correlates of 28- S113 day mortality. The independent predictors of mortality were APACHE III risk of hospital death (HR 1.3 (1.1–1.5), P = 0.003), and increased LV end systolic volume (HR 2.1 (1.2–3.7), P = 0.007). Indices of ventricular filling pressure (E/E′, left atrial area/volume) were not predictors of mortality. Prehospital echocardiography in pulseless electrical activity victims using portable, handheld ultrasound C Byhahn1, E Müller2, F Walcher1, H Steiger2, F Seeger1, R Breitkreutz1 1JW Goethe-University Hospital, Frankfurt, Germany; 2Emergency Medical Service, Darmstadt, Germany Critical Care 2007, 11(Suppl 2):P279 (doi: 10.1186/cc5439) C Byhahn1, E Müller2, F Walcher1, H Steiger2, F Seeger1, R Breitkreutz1 1JW Goethe-University Hospital, Frankfurt, Germany; 2Emergency Medical Service, Darmstadt, Germany Critical Care 2007, 11(Suppl 2):P279 (doi: 10.1186/cc5439) Objective Potentially treatable causes of sudden cardiac arrest, such as pericardial tamponade, myocardial insufficiency or hypo- volemia, should be identified as soon as possible (that is, at the scene). Although these diagnoses are mainly made by echo- cardiography, old and new ERC or ILCOR guidelines only recom- mend pauses of ventilation or chest compressions as ‘brief interrup- tions’ at a maximum of 10 seconds, thereby potentially limiting transthoracic ultrasound examinations. We introduced an ALS- based algorithm of focused echocardiographic evaluation during resuscitation (FEER) to be performed in a time-sensitive manner. Table 1 (abstract P280) Chamber 689 Left ventricular function 670 Inferior vena cava 571 Mitral E/A 399 Isovolumetric relaxation time 569 Tricuspid regurgitation 291 Cardiac output 610 All patients 704 P282 Determination of intravascular volume status in critically ill patients using portable chest X-rays: measurement of the vascular pedicle width Background Assessment of preload and goal-directed resusci- tation are crucial parts of ICU therapy. To assess preload, clinical parameters such as filling of the jugular veins, edema and pleural effusions as well as X-ray are used. In addition, haemodynamic parameters such as the central venous pressure (CVP), pulmonary arterial wedge pressure and PiCCO-derived global end-diastolic volume index (GEDVI) are determined. The GEDVI has been shown to be superior to pressure-based parameters with regard to volume responsiveness in several studies. However, PiCCO data are not available in all patients, and frequently clinical examination, CVP and chest X-ray are the first tools for preload assessment. It was the aim of our study to evaluate clinical assessment, X-ray and CVP with regard to the GEDVI and extravascular lung water index (ELWI). N Salahuddin, I Chishti, S Siddiqui Aga Khan University & Hospital, Karachi, Pakistan Critical Care 2007, 11(Suppl 2):P282 (doi: 10.1186/cc5442) Introduction Traditionally invasive haemodynamic measurements of pulmonary artery occlusion pressures have been used to assess the volume status in critically ill patients. The vascular pedicle, as seen on chest X-ray scan, is the mediastinal silhouette of the great vessels. We hypothesized that the vascular pedicle width (VPW) on supine, portable chest X-ray scans could be used to predict intravascular volume overloaded status in critically ill patients. Methods We conducted a prospective, blinded observational trial where both pulmonary artery occlusion pressures (PAOP) and VPWs were measured in patients admitted to the ICU. We used measurements of PAOP ≥18 mmHg as indicative of a fluid overloaded state, and measurements of PAOP < 18 mmHg as normal or low volume states. Standardized, portable chest X-ray scans in the supine position were obtained within 1 hour of PAOP measurement. Receiver-operating characteristics (ROC) curves were constructed using different cutoffs of the VPW measurement to identify sensitivities and specificities for each value (see Figure 1). Results Measurements were obtained from 50 patients. Using ROC-derived cutoffs, a VPW measurement of 74.5 mm was found to have a sensitivity of 83% and a specificity of 78% for correctly predicting a fluid overloaded state. Methods In 86 patients of an internal ICU, clinical examination was independently determined by a physician and investigator not working in the ICU. P283 The role of clinical examination, chest X-ray and central venous pressure in volume assessment in critically ill patients: a comparison with PiCCO-derived data W Huber, S Ringmaier, A Umgelter, K Holzapfel, W Reindl, M Franzen, J Gaa, R Schmid Klinikum Rechts der Isar, Technical University of Munich, Germany Critical Care 2007, 11(Suppl 2):P283 (doi: 10.1186/cc5443) The role of clinical examination, chest X-ray and central venous pressure in volume assessment in critically ill patients: a comparison with PiCCO-derived data W Huber, S Ringmaier, A Umgelter, K Holzapfel, W Reindl, M Franzen, J Gaa, R Schmid Klinikum Rechts der Isar, Technical University of Munich, Germany Critical Care 2007, 11(Suppl 2):P283 (doi: 10.1186/cc5443) The role of clinical examination, chest X-ray and central venous pressure in volume assessment in critically ill patients: a comparison with PiCCO-derived data W Huber, S Ringmaier, A Umgelter, K Holzapfel, W Reindl, M Franzen, J Gaa, R Schmid Klinikum Rechts der Isar, Technical University of Munich, Germany Critical Care 2007, 11(Suppl 2):P283 (doi: 10.1186/cc5443) P281 Patients with ischemic, dilated, hypertrophic cardiomyopathy, severe valvular disease, uncontrolled blood pressure and chronic atrial fibrillation were excluded. Results No differences were observed in the LV systolic performance by use of the conventional 2D echocardiography between the two groups (EF: 63.8 ± 3.7% in Group A as compared with 64 ± 4.8% in Group B, P = not significant). Nevertheless, differences were ascertained in the maximum systolic velocities on the long axis using TDI. Sm: 8.2 ± 1.1 m/s in Group A, 9.7 ± 1 m/s in Group B (P = 0.04), Sl: 10.6 ± 1.3 m/s in Group A, 13.6 ± 1.4 m/s in Group B (P = 0.02). Receiver-operating characteristics curve for vascular pedicle width. The curve shows the ability of the vascular pedicle width to differentiate between fluid overload and euvolemia at different cutoff points. The area under the curve is 0.724. Increased vascular volume is defined as pulmonary artery occlusion pressure ≥18 mmHg. Receiver-operating characteristics curve for vascular pedicle width. The curve shows the ability of the vascular pedicle width to differentiate between fluid overload and euvolemia at different cutoff points. The area under the curve is 0.724. Increased vascular volume is defined as pulmonary artery occlusion pressure ≥18 mmHg. Conclusion TDI echocardiography identifies LV contractility abnormalities in ICU septic patients that appear to have a normal EF in the conventional echocardiogram, so it provides earlier recognition and treatment of LV dysfunction related to sepsis. P281 P281 Identification of contractility abnormalities in intensive care unit patients with sepsis using tissue Doppler imaging H Michalopoulou, P Stamatis, A Bakhal, T Kelgiorgis, A Basile, J Vaitsis, E Reinou, P Batika, D Pragastis, A Foundouli Metaxa Hospital, Athens, Greece Critical Care 2007, 11(Suppl 2):P281 (doi: 10.1186/cc5441) Identification of contractility abnormalities in intensive care unit patients with sepsis using tissue Doppler imaging H Michalopoulou, P Stamatis, A Bakhal, T Kelgiorgis, A Basile, J Vaitsis, E Reinou, P Batika, D Pragastis, A Foundouli Metaxa Hospital, Athens, Greece Critical Care 2007, 11(Suppl 2):P281 (doi: 10.1186/cc5441) H Michalopoulou, P Stamatis, A Bakhal, T Kelgiorgis, A Basile, J Vaitsis, E Reinou, P Batika, D Pragastis, A Foundouli Metaxa Hospital, Athens, Greece Critical Care 2007, 11(Suppl 2):P281 (doi: 10.1186/cc5441) Conclusions Application of FEER was feasible within a 10-second time-frame of CPR interruptions. While differentiating PEA states, FEER has the ability to identify a pseudo-PEA state, allowing further treatment of the underlying disorder on the scene to improve outcome. Introduction Tissue Doppler imaging (TDI), as a more recent ultrasound technique, is a precious diagnostic tool revealing earlier S114 Available online http://ccforum.com/supplements/11/S2 Figure 1 (abstract P282) Receiver-operating characteristics curve for vascular pedicle width. The curve shows the ability of the vascular pedicle width to differentiate between fluid overload and euvolemia at different cutoff points. The area under the curve is 0.724. Increased vascular volume is defined as pulmonary artery occlusion pressure ≥18 mmHg. Figure 1 (abstract P282) Figure 1 (abstract P282) left ventricular (LV) contractility abnormalities as compared with the conventional echocardiography. This study aimed at assessing the contribution of TDI to the early diagnosis of LV systolic dysfunction in ICU septic patients maintaining a normal ejection fraction (EF). Methods Twenty-two ICU patients of average age 57.6 ± 7.3 years (13 males) (Group A) and 20 seemingly healthy individuals (Group B) were studied. The ICU patients met the sepsis criteria (infection by Gram-negative bacterium and, at least, two of the SIRS criteria). The APACHE II score mean value was 21.2 ± 4.9. All the patients of the study were subjected to the same session in a 2D echo- cardiogram. The EF of the left ventricle was calculated according to Simpson’s method. The systolic velocities on the long axis were measured by TDI, placing the sample volume 0.5 cm distance from the mitral annular in the basic posterior interventricular septum (Sm) and on the lateral wall (Sl). Change of therapeutic plan following advanced cardiopulmonary monitoring in critically ill patients: a multicenter study A Perel1, M Maggiorini2, M Malbrain3, J Teboul4, J Belda5, E Fernández Mondéjar6, M Kirov7, J Wendon8 1Sheba Medical Center, Tel Hashomer, Israel; 2Universitatsspital, Zurich, Switzerland; 3Ziekenhuis Netwerk Antwerpen-Hospital Campus Stuivenberg, Antwerp, Belgium; 4Hôpital De Bicêtre, Le Kremlin-Bicêtre, France; 5Hospital Clinico Universitario, Valencia, Spain; 6Hospital Universitario Virgen De Las Nieves, Granada, Spain; 7Northern State Medical University, Arkhangelsk, Russian Federation; 8King’s College Hospital, London, UK Critical Care 2007, 11(Suppl 2):P284 (doi: 10.1186/cc5444) A Perel1, M Maggiorini2, M Malbrain3, J Teboul4, J Belda5, E Fernández Mondéjar6, M Kirov7, J Wendon8 1Sheba Medical Center, Tel Hashomer, Israel; 2Universitatsspital, Zurich, Switzerland; 3Ziekenhuisnetwerk Antwerpen, Campus Stuivenberg, Antwerp, Belgium; 4Hopital De Bicetre, Le Kremlin Bicetre, France; 5Hospital Clinico Universitario, Valencia, Spain; 6Hospital Universitario Virgen de las Nieves, Granada, Spain; 7Northern State Medical University, Arkhangelsk, Russian Federation; 8Liver Intensive Care Unit, London, UK Critical Care 2007, 11(Suppl 2):P285 (doi: 10.1186/cc5445) A Perel1, M Maggiorini2, M Malbrain3, J Teboul4, J Belda5, E Fernández Mondéjar6, M Kirov7, J Wendon8 1Sheba Medical Center, Tel Hashomer, Israel; 2Universitatsspital, Zurich, Switzerland; 3Ziekenhuisnetwerk Antwerpen, Campus Stuivenberg, Antwerp, Belgium; 4Hopital De Bicetre, Le Kremlin Bicetre, France; 5Hospital Clinico Universitario, Valencia, Spain; 6Hospital Universitario Virgen de las Nieves, Granada, Spain; 7Northern State Medical University, Arkhangelsk, Russian Federation; 8Liver Intensive Care Unit, London, UK Critical Care 2007, 11(Suppl 2):P285 (doi: 10.1186/cc5445) Introduction Lack of evidence that more advanced monitoring techniques improve outcome may have led to insufficient monitoring of critically ill patients. However, clinical judgment and conventional hemodynamic monitoring alone were shown to be inadequate for a reliable estimate of hemodynamic status. We have therefore compared clinicians’ prediction of advanced cardio- pulmonary parameters with actual measurements. Introduction Many therapeutic decisions are made in the ICU on the basis of clinical judgment and conventional monitoring alone, although these may be inadequate for a reliable estimate of hemodynamic status. We therefore measured the effects of more advanced cardiopulmonary parameters (ACP) on major therapeutic decisions. Methods Cardiopulmonary assessment was done in critically ill patients from 12 European ICUs independently by one to four physicians per patient just before the use of the PiCCO monitor (Pulsion, Germany). Following cardiopulmonary evaluation and prediction of ACP (reported elsewhere), each physician suggested a therapeutic plan before and after the first set of PiCCO measure- ments (cardiac output, systemic vascular resistance, global end- diastolic volume, stroke volume variation, and extravascular lung water), and then self-rated the accuracy of his original therapeutic plan. Change of therapeutic plan following advanced cardiopulmonary monitoring in critically ill patients: a multicenter study Methods Cardiopulmonary assessment was done in critically ill patients from 12 European ICUs just before the use of the PiCCO monitor (Pulsion, Germany). Independent prediction of cardiac output (CO), systemic vascular resistance (SVR), indexed global end-diastolic volume (GEDVi), stroke volume variation (SVV), and indexed extravascular lung water (EVLWi) was done by one to four physicians per patient. Following the first set of PiCCO measurements each physician self-rated the accuracy of his pre- PiCCO predictions. Results A total of 257 questionnaires of 165 patients (67 females and 98 males, age 59.8 ± 16.7 (range 16–93) years) were completed by 135 residents and 122 specialists. The main reasons for using the PiCCO included unclear fluid status (109 cases), sepsis/septic shock (70 cases), respiratory failure (42 cases), cardiogenic shock (19 cases), renal failure (27 cases), and other (18 cases). Only 30–50% of the predicted values were correct (±20% of measured values) (Table 1). Ranges of errors were: CO (–77/+100%), SVR (–94/+303%), GEDVi (–88/+135%), SVV (–91/+367%), EVLWi (–76/+650%). There was a significant underestimation of CO (P < 0.00001) and GEDVi (P < 0.0003), and overestimation of SVR (P < 0.003) and SVV (P < 0.0002). Results A total of 257 questionnaires of 165 patients (67 females and 98 males, age ± SD 59.8 ± 16.7 (range 16–93) years) were completed by 135 residents and 122 specialists. The main reasons for using the PiCCO included unclear fluid status (109 cases), sepsis/septic shock (70 cases), respiratory failure (42 cases), cardiogenic shock (19 cases), renal failure (27 cases), other (18 cases). Changes (plan-and-not-give and no-plan-and- give) made in the pre-PiCCO therapeutic plans included: fluid, 31.8%; inotropes, 23.3%; vasoconstrictors, 23.5%; diuretics, 15% (Table 1). The 240 overall self-ratings of the original plan (scale of 1–5, [1] = not different; [5] = very different) included – [1] 33.7%, [2] 23.5%, [3] 25.9%, [4] 11.5%, [5] 5.3%. The mean self-rate was 2.3 ± 1.2, with that of residents (2.3 ± 1.3, n = 129) being similar to that of specialists (2.3 ± 1.1, n = 111), P < 0.88. Clinicians’ prediction of advanced cardiopulmonary variables in critically ill patients: a multicenter study Change of therapeutic plan following advanced cardiopulmonary monitoring in critically ill patients: a multicenter study Clinicians’ prediction of advanced cardiopulmonary variables in critically ill patients: a multicenter study P282 Subsequently, chest X-ray (analysed by an experienced radiologist), CVP and PiCCO (Pulsion Company, Munich, Germany) measurements were performed and these data were correlated to clinical findings. Results Patients (n = 86; 34 females, 52 males) included 25 patients with cirrhosis, 18 patients with pancreatitis, 19 patients with sepsis; age 63.0 ± 15.5 years; APACHE II score 23.3 ± 8.4. Leg edema significantly correlated to CVP (r = 0.247; P = 0.038) and (negatively) to GEDVI (r = –0.258; P = 0.032). CVP and GEDVI were not associated: r = 0.035; P = 0.784. The ELWI significantly correlated to the degree of rales (r = 0.258; P = 0.016) and GEDVI (r = 0.557; P < 0.001). The ELWI and CVP did not correlate (r = 0.030; P = 0.785). Global clinical preload assess- Conclusions These results suggest that serial measurements of the VPW can reliably be used to predict intravascular volume overload in the ICU. S115 15.1%, [5] 4.5%. The mean self-rate was 2.8 ± 0.9, with that of residents (2.8 ± 0.9, n = 129) being similar to that of specialists (2.7 ± 0.8, n = 111), P < 0.31. ment (scale 1–10) was not predictive for GEDVI. Radiological assessment significantly overestimated the GEDVI (901.41 ± 139.76 vs 782.56 ± 183.80 ml/m2; P < 0.001) and underestimated the ELWI (7.22 ± 1.38 vs 9.77 ± 4.51 ml/kg; P < 0.001). Conclusions (1) Leg edema and increased CVP do not exclude preload deficiency determined by the GEDVI, which was overestimated by X-ray. (2) CVP and leg edema are poor predictors of the ELWI, which was significantly associated with audible rales but underestimated by X-ray. ment (scale 1–10) was not predictive for GEDVI. Radiological assessment significantly overestimated the GEDVI (901.41 ± 139.76 vs 782.56 ± 183.80 ml/m2; P < 0.001) and underestimated the ELWI (7.22 ± 1.38 vs 9.77 ± 4.51 ml/kg; P < 0.001). Conclusions The ability of physicians to predict advanced cardiopulmonary parameters based on clinical evaluation and conventional monitoring alone has considerable limitations and is not improved by experience. Conclusions (1) Leg edema and increased CVP do not exclude preload deficiency determined by the GEDVI, which was overestimated by X-ray. (2) CVP and leg edema are poor predictors of the ELWI, which was significantly associated with audible rales but underestimated by X-ray. Acknowledgement The authors of this unsupported study are members of Pulsion’s medical advisory board. P286 Assessment of extravascular lung water and pulmonary vascular permeability evaluated by the pulse contour cardiac output in systemic inflammatory response syndrome patients K Morisawa, Y Taira St Marianna University School of Medicine, Kwasaki-shi, Japan Critical Care 2007, 11(Suppl 2):P286 (doi: 10.1186/cc5446) Results We found a statistically significant correlation of both inspiratory and expiratory IVC diameter with central venous pressure (P = 0.004 and P = 0.001), extravascular lung water index (P = 0.001 and P < 0.001), intrathoracic blood volume index (P = 0.026 and P = 0.05), the intrathoracic thermal volume (both P < 0.001), and the paO2/FiO2 oxygenation index (P = 0.007 and P = 0.008, respectively). Introduction Pulse contour cardiac output (PiCCO) provides an estimate of the intrathoracic blood volume (ITBV), extravascular lung water (EVLW), and pulmonary vascular permeability index (PVPI). Few investigations have prospectively examined EVLW in patients with severe sepsis or ARDS. Introduction Pulse contour cardiac output (PiCCO) provides an estimate of the intrathoracic blood volume (ITBV), extravascular lung water (EVLW), and pulmonary vascular permeability index (PVPI). Few investigations have prospectively examined EVLW in patients with severe sepsis or ARDS. Objective The aim of this study was compare measurements of ITBV, EVLW, and PVPI in systemic inflammatory response syndrome (SIRS) patients. Conclusions Sonographic determination of the IVC diameter is useful in the assessment of volume status in mechanically ventilated septic patients. This approach is rapidly available, noninvasive, inexpensive, easy to learn and applicable in almost any clinical situation without doing harm. IVC sonography may contribute to a faster, more goal-oriented optimization of fluid status and may help to identify patients in whom deleterious volume expansion should be avoided. It remains to be elucidated whether this approach influences the outcome of septic patients. Materials and methods Twenty-eight adult patients with SIRS admitted to our ICU were studied in three groups. Group A, nine patients with pneumonia; group B, nine patients with extrathoracic infection; group C, 10 patients without infection were enrolled. In each patient, PiCCO was used to measure the ITBV and EVLW for 3 days of meeting criteria for SIRS. The PVPI was calculated as the ratio of EVLW to ITBV. EVLW values were indexed by the predicted body weight and ITBV values were indexed by the predicted body surface. All data are presented as mean ± standard deviation. P287 Fluid status assessment in mechanically ventilated septic patients J Schefold1, C Storm1, A Krüger1, M Oppert1, D Hasper2 1Charite University Medicine Berlin, Germany; 2Charite Campus Virchow, Berlin, Germany Critical Care 2007, 11(Suppl 2):P287 (doi: 10.1186/cc5447) Conclusions The measurement of advanced cardiopulmonary parameters caused both specialists and residents to make considerable changes in therapeutic decisions that were previously made based on clinical judgment and conventional monitoring alone. Background Early optimization of fluid status is of major importance in the treatment of critically ill patients. It is unclear whether sonographic measurement of the inferior vena cava (IVC) diameter is valuable in the evaluation of fluid status in mechanically ventilated septic patients. Acknowledgement The authors of this unsupported study are members of Pulsion’s medical advisory board. Methods Thirty mechanically ventilated patients with severe sepsis or septic shock (age 59.9 ± 15.4 years; APACHE II score 30.6 ± 7.7; 18 males) requiring advanced invasive hemodynamic monitoring due to cardiovascular instability were included in a prospective observational study in a university hospital setting with a 24-bed medical ICU and a 14-bed anaesthesiological ICU. Volume-based hemodynamic parameters were determined using the thermal-dye transpulmonary dilution technique. Simultaneously, the IVC diameter was measured throughout the respiratory cycle by trans- abdominal ultrasonography. P286 The Kruskal–Wallis H test was performed for statistical analysis and P < 0.05 was considered statistically significant. Change of therapeutic plan following advanced cardiopulmonary monitoring in critically ill patients: a multicenter study The 240 self-ratings (scale of 1–5, [1] = excellent; [5] = poor) of predictions accuracy included – [1] 1.6%, [2] 40%, [3] 38.8%, [4] S116 Table 1 (abstract P284) EVLWi % CO % SVR % GEDVi % SVV % Under 69 29.4 127* 49.6 46 18.1 72 28 85 39.7 Correct 93 39.6 99 38.6 90 35.4 93 50.2 64 29.9 Over 73 31.1 30 11.7 116 45.7 73 21 65 30.4 *Number of predictions. S116 Available online http://ccforum.com/supplements/11/S2 B. The EVLWI and PVPI were significantly higher in group B than in group C too. Conclusion Our data indicate that the permeability of pulmonary vessels is increased more with infection than without infection, and is also higher with pneumonia than with extrathoracic infection in SIRS patients. P287 Fluid status assessment in mechanically ventilated septic patients J Schefold1, C Storm1, A Krüger1, M Oppert1, D Hasper2 1Charite University Medicine Berlin, Germany; 2Charite Campus Virchow, Berlin, Germany Critical Care 2007, 11(Suppl 2):P287 (doi: 10.1186/cc5447) Table 1 (abstract P285) Given % Not given % Fluid P 109 43 53 21 Fluid NP 28 11 65 25 Inotropes P 33 13 46 18 Inotropes NP 14 5 164 64 Vasoconstrictors P 50 20 36 14 Vasoconstrictors NP 24 9 143 57 Diuretics P 19 7 20 8 Diuretics NP 18 7 197 78 P = planned; NP = not planned. Table 1 (abstract P285) Conclusion Our data indicate that the permeability of pulmonary vessels is increased more with infection than without infection, and is also higher with pneumonia than with extrathoracic infection in SIRS patients. P288 Noninvasive cardiac output: accuracy between the ultrasound cardiac output monitor and the esophageal Doppler monitor Results See Table 1. One hundred and forty samples of data were collected. The mean PVPI value was within the normal range. The EVLWI and PVPI were significantly higher in group A than in group R Bilkovski1, J Martini1, R Phillips2 1Henry Ford Hospital, Detroit, MI, USA; 2University of Queensland, Brisbane, Australia Critical Care 2007, 11(Suppl 2):P288 (doi: 10.1186/cc5448) Table 1 (abstract P286) Group A Group B Group C ITBVI 933 ± 256 977 ± 197 996 ± 407 EVLWI 12 ± 5 10 ± 4* 8 ± 3*,** PVPI 2.3 ± 1.1 1.8 ± 0.8* 1.6 ± 0.7*,** *P < 0.05 vs group A. **P < 0.05 vs group A and group B. Introduction The hypothesis is that measurement of the cardiac index (CI) is accurate between the ultrasound cardiac output monitor (USCOM) and the esophageal Doppler monitor (EDM). The EDM is a minimally invasive device that has demonstrated strong correlation with cardiac output measurements obtained by thermodilution. A disadvantage of the EDM is the need for probe placement in the esophagus, effectively limiting its use to S117 *P < 0.05 vs group A. **P < 0.05 vs group A and group B. Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Figure 1 (abstract P289) mechanically ventilated patients. The USCOM, in contrast, can measure cardiac hemodynamics by use of a CW Doppler probe placed on the skin to measure blood flow across either the aortic or pulmonic valve. mechanically ventilated patients. The USCOM, in contrast, can measure cardiac hemodynamics by use of a CW Doppler probe placed on the skin to measure blood flow across either the aortic or pulmonic valve. Mixed venous hemoglobin oxygen saturation (SvO2) vs cardiac output (CO) by noninvasive cardiac output monitoring and Swan on Mister197. Methods A prospective study of adult ED patients who were intubated and managed concurrently with an EDM. Setting: urban tertiary care center with >90,000 annual visits. Exclusion criteria: ESRD, ascites, known valvular heart disease and pre-existing tracheotomy. IRB approval was obtained with waiver of informed consent. USCOM measurements of CI were obtained, blinded to EDM values measured concurrently. Noninvasive cardiac output monitoring: a clinical validation P Squara, P Estagnasie, A Brusset, D Denjean, J Dib, C Dubois CERIC, Neuilly-sur-Seine, France Critical Care 2007, 11(Suppl 2):P289 (doi: 10.1186/cc5449) M Cecconi1, J Poloniecki2, G Della Rocca3, J Ball1, R Grounds1, A Rhodes1 1St George’s Hospital, London, UK; 2St George’s University of London, UK; 3University of Udine, Italy Critical Care 2007, 11(Suppl 2):P290 (doi: 10.1186/cc5450) Introduction Our objective was to evaluate the clinical utility of noninvasive cardiac output monitoring (NICOM), a new tool for automatic continuous cardiac output (CO) monitoring based on chest bioreactance, using continuous thermodilution as reference (PAC-CCO). Introduction The Bland–Altman plot is the standard way of determining agreement between two methods of measuring the same variable. Following work by Critchley and Critchley [1], ±30% is now accepted as the cutoff point when calculating the percentage error. This study estimates the coefficient of variation (CV) of three different cardiac output (CO) techniques with the aim of assessing the relative contributions to the percentage error. Introduction The Bland–Altman plot is the standard way of determining agreement between two methods of measuring the same variable. Following work by Critchley and Critchley [1], ±30% is now accepted as the cutoff point when calculating the percentage error. This study estimates the coefficient of variation (CV) of three different cardiac output (CO) techniques with the aim of assessing the relative contributions to the percentage error. Method We included 110 consecutive adult patients immediately after cardiac surgery in a prospective, single-center study taking place in the ICU. CO measurements obtained from NICOM and PAC-CCO were simultaneously recorded minute by minute (Figure 1). We evaluated the accuracy, precision, responsiveness, and reliability of NICOM for detecting CO changes. Tolerance for each of these parameters was specified prospectively. Materials and methods Thirty critically ill patients had their CO measured every hour with continuous cardiac output by Vigilance (CCO), pulse pressure analysis by LiDCO™plus (PulseCO) and intermittent thermodilution (ITD) (average of four ITD curves). Data were analysed with Bland–Altman plots, calculation of the percentage error, determination of the CV of ITD, and calculation of the overall CV for CCO and PulseCO. Results A total of 65,888 pairs of CO measurements were collected. Mean reference values for PAC-CCO ranged from 2.79 to 9.27 l/min. P290 Method comparison – a new approach to implementing the Bland–Altman analysis to estimate the precision of a new method: tested on 30 critically ill patients monitored with pulse pressure analysis and continuous cardiac output vs intermittent thermodilution P288 Repeated pairs were obtained every 30–60 minutes, in a similar manner. Statistical analysis: correlation and Bland–Altman plots using SPSS 9.0. Results A total of 95 paired measures were obtained from 20 patients with an average age of 60.1 years, 60% male and 70% African American. The mean CI was 5.2 with a range of 1.4–6.6 l/min/m2. For the aggregate, r = 0.81 (P < 0.001) and bias was 0.14 with limits of agreement (LOA) of –1.48 to 1.76. Excess scatter was noted at CI > 4.0 CI. For CI < 4.0, correlation was 0.80 (P < 0.001) with bias and LOA of –0.15 and –1.01 to 0.71. At CI < 2.5, greater accuracy was noted with bias of 0.01 and LOA of 0.73 to 0.75. Mixed venous hemoglobin oxygen saturation (SvO2) vs cardiac output (CO) by noninvasive cardiac output monitoring and Swan on Mister197. Conclusions CI measurement with the USCOM has a high degree of agreement with the EDM, most notably when CI is below 4.0. Of particular interest is the high degree of accuracy seen at low CI values (<2.5). These findings support the use of the USCOM for CI measurement in mechanically ventilated patients and a wider range of patients in which the EDM would be impractical or difficult to use. Conclusion CO measured by NICOM had most often acceptable accuracy, precision, and responsiveness in a wide range of circulatory situations. P291 P291 Comparison of vascular pedicle width and PiCCO-derived haemodynamic measurements in patients in a general intensive care unit S Aloizos1, G Liapis1, D Maragiannis1, E Tsigou2, P Aravosita2, E Evodia2 1401 General Army Hospital Athens, Greece; 2Mother General & Surgical Hospital, Athens, Greece Critical Care 2007, 11(Suppl 2):P291 (doi: 10.1186/cc5451) Comparison of vascular pedicle width and PiCCO-derived haemodynamic measurements in patients in a general intensive care unit Methods Our study includes 140 measurements in 10 critically ill patients (eight males, two females, age 37–84 years, mean 64.1 ± 13.0 years) requiring hemodynamic monitoring with the PiCCO system. Five patients had septic shock, three hepatorenal syndrome and two acute heart failure. First the CIpc was recorded immediately before the next calibration and afterwards the CItd was measured three times, which resulted in a simultaneous calibration of the pulse contour algorithm of the PiCCO system. We performed a mean of 14 ± 9.4 measurements per patient. The time-lag between the measurements was 12 hours 54 minutes ± 7 hours 47 minutes. intensive care unit S Aloizos1, G Liapis1, D Maragiannis1, E Tsigou2, P Aravosita2, E Evodia2 1401 General Army Hospital Athens, Greece; 2Mother General & Surgical Hospital, Athens, Greece Critical Care 2007, 11(Suppl 2):P291 (doi: 10.1186/cc5451) Introduction Assessing clinically the intravascular volume status of critically ill patients can be exceedingly difficult. Due to concerns about the efficacy and safety (possible increase in mortality) of using invasive haemodynamic monitoring, noninvasive diagnostic testing has gained increasing importance. Results The comparison of the CIpc immediately before calibration and the calibration-derived CItd resulted in a correlation coefficient of 0.84 with a P value of 0.02. In the Bland–Altman analysis the CIpc was a mean 0.14 l/min/m2 lower than the CItd. The standard deviation was 0.72 l/min/m2. There was no correlation of the time- lag between the calibrations and the difference of CIpc and CItd (r = –0.03; P = 0.13). Objective To compare the reliability of vascular pedicle width (VPW) as an indicator of overload, in patients of a general ICU, with a method of invasive haemodynamic monitoring that has proved its efficacy in the literature and in everyday practice. Patients and methods The VPW, which represents the media- stinal silhouette of the great vessels, was compared with the haemodynamic measurements, which were obtained with the method of transpulmonary thermodilution (PiCCO Plus; Pulsion, Munich, Germany). Reliability of the continuous cardiac index measurement using the pulse contour analysis of the PiCCO system Reliability of the continuous cardiac index measurement using the pulse contour analysis of the PiCCO system Conclusions In trying to understand the relative contributions of error when testing two techniques to measure the same variable it is vital to understand the CV of the reference technique. Using this approach, both the PulseCO and Vigilance perform in a clinically acceptable fashion. M Franzen, A Umgelter, S von Delius, A Weber, J Reichenberger, M Dohmen, R Schmid, W Huber Klinikum rechts der Isar, München, Germany Critical Care 2007, 11(Suppl 2):P292 (doi: 10.1186/cc5452) Reference 1. Critchley LA, Critchley JA: A meta-analysis of studies using bias and precision statistics to compare cardiac output measurement techniques. J Clin Monit Comput 1999, 15: 85-91. 1. Critchley LA, Critchley JA: A meta-analysis of studies using bias and precision statistics to compare cardiac output measurement techniques. J Clin Monit Comput 1999, 15: 85-91. Introduction Reliable continuous hemodynamic monitoring of critically ill patients is essential for effective volume management and adequate administration of vasoactive drugs. The PiCCO system allows continuous measurement of the cardiac index using arterial pulse contour analysis. Calibration of this system by transpulmonary thermodilution is recommended every 8 hours. In this study we compared the difference of the continuous measure- ment of the cardiac index using the arterial pulse contour analysis (CIpc) with the cardiac index acquired by the transpulmonary thermodilution (CItd) when calibrating the system. Noninvasive cardiac output monitoring: a clinical validation During periods of stable PAC-CCO (slope < ±10%, 2SD/mean <20%), the correlation between NICOM and PAC- CCO was R = 0.82; bias was +0.16 ± 0.52 l/min (+4.0 ± 11.3%), and the relative error was 9.1 ± 7.8%. In 85% of patients the relative error was <20%. During periods of increasing CO, slopes were similar with the two methods in 96% of patients and intraclass correlation was positive in 96%. Corresponding values during periods of decreasing CO were 90% and 84%, respectively. Precision was always better with NICOM than with PAC-CCO. During hemodynamic challenges, changes were 3.1 ± 3.8 minutes faster with NICOM (P < 0.01) and amplitude of changes were not different (not significant). Finally, sensitivity of the NICOM for detecting significant directional changes was 93% and specificity was 93%. Results Two hundred and forty (eight per patient) measurements of CO were obtained. CCO vs ITD had an overall bias (±2SD) of 0.2 ± 2.4 l/min (error 31%), mean CO (ITD + CCO) 7.7 l/min. PulseCO vs ITD had an overall bias of –0.1 ± 2.4 l/min, mean CO (PulseCO + ITD) 7.5 l/min (error 33%). According to the above criteria (without measuring the CV for ITD), CCO performed well when compared with ITD (31%) but PulseCO (33%) was outside clinically acceptable levels of agreement. The CV for a single ITD CO measurement was 15%, and this decreased to 7.5% when averaging four thermodilution curves. Using the CV for ITD of 7.5%, the relative CVs for the CCO and PulseCO were S118 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 P292 Reliability of the continuous cardiac index measurement using the pulse contour analysis of the PiCCO system M Franzen, A Umgelter, S von Delius, A Weber, J Reichenberger, M Dohmen, R Schmid, W Huber Klinikum rechts der Isar, München, Germany Critical Care 2007, 11(Suppl 2):P292 (doi: 10.1186/cc5452) P292 determined. The CV for CCO was 13.6% and for PulseCO was 14.7%. P291 We measured the VPW in anteroposterior chest X-rays in the supine position, with standard parameters, in 100 patients without prior cardiac surgery, prior mediastinal irradiation, obesity, severe acute respiratory distress syndrome and positive end-expiratory pressure > 7.5 cmH2O. In every patient we performed invasive haemodynamic monitoring with the PiCCO Plus. An intrathoracic blood volume index (ITBI) > 1,000 ml/m2, global end-diastolic index (GEDI) > 800 ml/m2, and extravascular lung water index (ELWI) > 7.0 ml/kg were considered the markers of significant volume overload. After further refinement, 27 patients fulfilled the above criteria and were considered eligible to be included in the study. Conclusion The PiCCO system allows a reliable continuous measurement of the cardiac index using the pulse contour analysis. In our study we could not find an increased difference of CIpc and CItd even with longer time periods between the calibrations using transpulmonary thermodilution. Because calibration is easy to achieve and additional data for the intrathoracic blood volume and the extravascular lung water are obtained, a 12-hour period between the calibrations is reasonable. PiCCO monitoring – are two injections enough? The mean CV for single lithium dilution was 12.3%. The CV for the average of n lithium dilutions was 8.6% for n = 2, 7.1% for n = 3, 6.1% for n = 4. Results Two hundred and forty-nine triplates were collected in 25 patients with septic shock, under mechanical ventilation. There were no significant differences in CI at each bolus. The average of the first two iced injections M1 = 3.28 ± 1.07 l/min/m2. The average of the triplate M2 = 5.74 ± 1.07. Conclusions The CV for one lithium dilution was higher than clinically acceptable (12.3 > 10%). The average of two lithium dilution measurements improves the precision by 30% and shows an excellent CV (that is, 8.6%). When measuring cardiac output with LiDCO an average of two lithium dilution curves provide an excellent precision, and we suggest that in this population (medical/surgical) this approach should always be used when calibrating the pulse pressure algorithm (PulseCO) at the baseline. Discussion Normally, we consider that 10–15% of variation in the CI signifies a change in the haemodynamic state. The difference between M1 and M2 exceeds 15%. In the literature, Nilsson and colleagues [1] demonstrated concerning the pulmonary arterial catheter that we need an average of at least four injections to be 95% confident. Conclusion With PiCCO monitoring, certainly two injections are not enough to have reliable measurement of the CI. Reference Conclusion With PiCCO monitoring, certainly two injections are not enough to have reliable measurement of the CI. Reference Conclusion With PiCCO monitoring, certainly two injections are not enough to have reliable measurement of the CI. 1. Nilsson LB, et al.: Acta Anaesthesiol Scand 2004, 48:1322- 1327. P295 P295 P294 Lithium dilution cardiac output measurement in the critically ill patient: determination of precision of the technique Transpulmonary lithium indicator dilution: a new method of intrathoracic blood volume measurement Transpulmonary lithium indicator dilution: a new method of intrathoracic blood volume measurement Lithium dilution cardiac output measurement in the critically ill patient: determination of precision of the technique M Cecconi, N Al-Subaie, M Canete, D Dawson, M Puntis, J Poloniecki, R Grounds, A Rhodes St George’s Hospital, London, UK Critical Care 2007, 11(Suppl 2):P294 (doi: 10.1186/cc5454) B Maddison, T Best, C Wolff, P Jones, C Hinds, R Pearse Barts & The London School of Medicine & Dentistry, London, UK Critical Care 2007, 11(Suppl 2):P295 (doi: 10.1186/cc5455) S120 , pp ( ) Introduction Pulmonary intermittent thermodilution (from the pu monary artery catheter), transpulmonary thermodilution (PiCCOplus Pulsion, Munich, Germany) and transpulmonary lithium dilutio (LiDCO™plus; LiDCO, Cambridge, UK) are all well-validated techniques in common use in intensive care for cardiac outpu estimation. The precision has been looked into previously and strategies to improve it have been made (that is, averaging three o four measurements over the respiratory cycle) yet not much i known about the precision of transpulmonary techniques in term of repeatability. This study aims to look into the coefficient o variation (CV) of the lithium dilution technique in a mixed (medical/surgical) intensive care population and propose a method to improve its precision. Materials and methods We performed four consecutive lithium dilution cardiac output determinations on 70 critically ill patient requiring haemodynamic monitoring. The heart rate (HR), centra venous pressure (CVP) and mean arterial pressure (mAP) were documented in conjunction with cardiac output estimation. Dat were excluded if a ±5% change in HR, CVP or mAP occurred during the sequential measurements. The CV ((SD/mean cardiac output) x 100) was calculated for single measurements and for the average of repeated measurements. In order to clinically accept the precision of the technique, we aimed to obtain a CV below 10%. Table 1 (abstract P295) Preoperative Post-CPB ITBVI (ml/m2) (n = 20) 739 (612–969) 1,078 (815–1,2 PBVI (ml/m2) (n = 16) 213 (201–279) 343 (307–37 CI (l/min/m2) (n = 20) 1.92 (0.45) 1.81 (0.42) Introduction Extravascular lung water (EVLW) measurement may improve outcome. Double indicator dilution, which is the most accurate method of EVLW measurement, is no longer commer- cially available. P295 Lithium indicator dilution could be used to measure the intrathoracic blood volume index (ITBVI) and therefore EVLW. Introduction Pulmonary intermittent thermodilution (from the pul- monary artery catheter), transpulmonary thermodilution (PiCCOplus; Pulsion, Munich, Germany) and transpulmonary lithium dilution (LiDCO™plus; LiDCO, Cambridge, UK) are all well-validated techniques in common use in intensive care for cardiac output estimation. The precision has been looked into previously and strategies to improve it have been made (that is, averaging three or four measurements over the respiratory cycle) yet not much is known about the precision of transpulmonary techniques in terms of repeatability. This study aims to look into the coefficient of variation (CV) of the lithium dilution technique in a mixed (medical/surgical) intensive care population and propose a method to improve its precision. Method A single-centre, observational study. Consent was sought from patients aged over 50 years undergoing elective cardiac surgery with cardiopulmonary bypass (CPB). Exclusion criteria included significant valvular regurgitation and lithium therapy. Anaesthetic, CPB, blood transfusion, ventilation and sedation practices were standardised. Indicator dilution measurements were performed following induction of anaesthesia, after CPB and then 2, 4 and 24 hours following surgery, using existing technology (LiDCO Ltd, London, UK). Data are presented as the median (IQR). Results Twenty patients were recruited (age 70 years (64–75 years); Parsonnet score 10 (1–14)). No difficulties were encoun- tered with the new method of ITBVI measurement. Absolute values and the changes in the ITBVI were close to those anticipated. Linear regression analysis did not indicate mathematical coupling between the cardiac index (CI) and the ITBVI (R2 = 0.22; P < 0.001). The relationship between the pulmonary blood volume index (PBVI) and the ITBVI was not constant. Materials and methods We performed four consecutive lithium dilution cardiac output determinations on 70 critically ill patients requiring haemodynamic monitoring. The heart rate (HR), central venous pressure (CVP) and mean arterial pressure (mAP) were documented in conjunction with cardiac output estimation. Data were excluded if a ±5% change in HR, CVP or mAP occurred during the sequential measurements. The CV ((SD/mean cardiac output) x 100) was calculated for single measurements and for the average of repeated measurements. In order to clinically accept the precision of the technique, we aimed to obtain a CV below 10%. Conclusion Lithium indicator dilution may be a valuable new method of ITBVI measurement, and therefore EVLW measurement. 1. Nilsson LB, et al.: Acta Anaesthesiol Scand 2004, 48:1322- 1327. Results Sixty-five series were suitable for analysis. The CV showed a normal distribution and no correlation with the magnitude of the mean cardiac output. The mean CV for single lithium dilution was 12.3%. The CV for the average of n lithium dilutions was 8.6% for n = 2, 7.1% for n = 3, 6.1% for n = 4. PiCCO monitoring – are two injections enough? S Alaya, S Abdellatif, R Nasri, H Ksouri, S Ben Lakhal Intensive Care Unit, Tunis, Tunisia Critical Care 2007, 11(Suppl 2):P293 (doi: 10.1186/cc5453) Results The mean VPW in overloaded patients was 75.14 mm compared with a mean of 64.71 mm for the rest. The results were subsequently analyzed using Spearman’s nonparametric test and we found correlation (0.785, 0.710, and 0.510) between VPW and the GEDI, ITBI, and ELWI, respectively. The results were considered statistically significant (P < 0.000, P < 0.000, and P < 0.005, respectively). Introduction PiCCO monitoring using the thermodilution technique has become an alternative method of invasive haemodynamic monitoring for the critically ill patient. Usually the results of an arbitrarily chosen number (one to five) of thermal indicator injections are averaged to increase the reliability of the measurement. The number of injections needed to achieve a given level of precision has, however, not previously been systematically investigated. We tried in this study to validate the accuracy of two injections instead of three injections. Introduction PiCCO monitoring using the thermodilution technique has become an alternative method of invasive haemodynamic monitoring for the critically ill patient. Usually the results of an arbitrarily chosen number (one to five) of thermal indicator injections are averaged to increase the reliability of the measurement. The number of injections needed to achieve a given level of precision has, however, not previously been systematically investigated. We tried in this study to validate the accuracy of two injections instead of three injections. Conclusion The VPW, when appropriately assessed at the bedside by the same physician and therefore avoiding the possible bias, using portable chest X-rays, might give very useful information regarding the volume status of the patients, results that are comparable in their efficacy with those obtained with invasive and more expensive methods. Methods We analysed retrospectively all data (triplate measure- ments) obtained during the past 2 years by PiCCO monitoring: injection of 10 ml saline solution three times by the same operator. S119 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin We compared the cardiac index (CI) obtained at each bolus, the average of the CI obtained at the first two injections (M1) and then the triplate (M2). Results Sixty-five series were suitable for analysis. The CV showed a normal distribution and no correlation with the magnitude of the mean cardiac output. P295 S120 Table 1 (abstract P295) Time 2 hours 4 hours 24 hours Preoperative Post-CPB postoperatively postoperatively postoperatively ITBVI (ml/m2) (n = 20) 739 (612–969) 1,078 (815–1,262) 1,266 (1,031–1,433) 1,188 (947–1,343) 1,008 (738–1,257) PBVI (ml/m2) (n = 16) 213 (201–279) 343 (307–371) 338 (288–449) 394 (305–545) 407 (267–464) CI (l/min/m2) (n = 20) 1.92 (0.45) 1.81 (0.42) 2.03 (0.56) 2.20 (0.58) 2.28 (0.94) Table 1 (abstract P295) S120 Available online http://ccforum.com/supplements/11/S2 Table 1 (abstract P297) Patient ItbiP ItbiL Difference (%) 1 894 960 7.4 2a 1,517 1,990 31 2b 1,572 1,078 –31.4 3 1,069 724 –32.3 4 1,280 1,318 3.0 5a 1,478 1,213 –17.9 5b 1,324 1,058 –20.1 5c 1,429 1,797 25.8 6a 732 731 –0.01 6b 787 627 –20.3 P296 P296 Comparison between uncalibrated cardiac output using the femoral and radial arterial pressure waveform in critically ill patients J Smith1, C Wolff2, E Mills2, K Lei1, C Taylor1, L Camporota1, R Beale1 1Guy’s & St Thomas’ NHS Foundation Trust, London, UK; 2LiDCO Ltd, London, UK Critical Care 2007, 11(Suppl 2):P296 (doi: 10.1186/cc5456) Introduction Cardiac output (CO) monitoring is often required to manage critically ill patients. Nominal values can be determined from analysis of arterial pressure waveforms. It is assumed that arterial waveforms from different arterial sites give similar CO values. The aim of this study was to compare the values of uncalibrated CO derived from simultaneous radial (COr) and femoral (COf) blood pressures. mean difference of LiDCO from PiCCO overall was –5.49 ± 21.3%. The correlation coefficient r = 0.73 (P = 0.0166). Conclusion There was general agreement between LiDCO and PiCCO. There were significant differences (>30%) in only three out of 10 measurements. Combining the results of >1 lithium calibration may improve accuracy. These results are promising but a larger trial will be required. mean difference of LiDCO from PiCCO overall was –5.49 ± 21.3%. The correlation coefficient r = 0.73 (P = 0.0166). Methods We enrolled 17 medical and surgical ICU patients, requiring haemodynamic monitoring and vasoactive drugs. Simultaneous recordings of the arterial radial and femoral waveforms were made from arterial pressure monitors via an A–D converter and analysed to obtain CO values using the PulseCO® algorithm of the LiDCOplus (LiDCO, London, UK). Paired CO values were selected at several points on each recording. Calibrations were not done at each time point so the comparison required examination of the ratio of uncalibrated COr and COf. Conclusion There was general agreement between LiDCO and PiCCO. There were significant differences (>30%) in only three out of 10 measurements. Combining the results of >1 lithium calibration may improve accuracy. These results are promising but a larger trial will be required. Impedance cardiography to assess hemodynamic status: a comparison with transpulmonary thermodilution Impedance cardiography to assess hemodynamic status: a comparison with transpulmonary thermodilution A Donati, R Nardella, V Gabbanelli, C Valentini, F Gabriele, P Pelaia AOU Umberto I Ancona, Italy Critical Care 2007, 11(Suppl 2):P298 (doi: 10.1186/cc5458) Introduction Measurement of extravascular lung water (EVLW) obtained with transpulmonary thermodilution (PiCCO system) can help the physician to guide fluid management of critically ill patients [1]. The thoracic fluid content (TFC) is a parameter deriving from the electric conductivity of the thorax, determined from intravascular, alveolar and interstitial fluids [2,3]. To the author's knowledge, there is no clinical study comparing PiCCO EVLW and the TFC provided by the impedance cardiac output (ICG) system. The aim of the study was to compare measurements of cardiac index (CI) obtained with PiCCO (P) and ICG before and after fluid challenge (FC), to evaluate whether the TFC can provide a noninvasive estimate of lung fluid balance, compared with PiCCO EVLW, in 10 critically ill patients. Conclusions CO derived from blood pressure records at radial and femoral sites can appear similar when a patient population as a whole is considered. However, in individual patients, the difference between the two sites is large enough to be clinically unacceptable without a site-specific recalibration. P298 Results The median value of the CO ratio was 0.95 (IQR 0.88–1.02), with a high variability across the patients, ranging from 0.3 to 1.41, whereas intrapatient variability was low, with a median CV of 3.26% (IQR 1.1–5.3%). Although the ratio in COs between the two sites varied greatly, the difference between the median (range) arterial pressures was 2 mmHg (–3 to 8 mmHg). However, the pulse pressure difference between the two sites was generally large with a median (range) of 2 mmHg (–26 to 44 mmHg). Measurement of intrathoracic blood volume by lithium dilution: comparison with thermodilution H Roberts, A Saayman, L Ala, G Findlay University Hospital of Wales, Cardiff, UK Critical Care 2007, 11(Suppl 2):P297 (doi: 10.1186/cc5457) Methods We studied 10 patients (eight males), aged 16-76 years (mean 22 ± SD 38), admitted to our ICU for head injury (three patients), septic shock (four patients), ARDS (one patient), and postsurgical (two patients). Introduction The intrathoracic blood volume is usually measured clinically by transpulmonary thermodilution (PiCCO system; Pulsion Ltd). New software also allows measurement at the bedside by lithium dilution (LiDCO system; LiDCO Ltd). We sought to compare the new lithium dilution method with the existing method. p g ( p ) The APACHE II score was 26-36 (30 ± 5). They were all moni- tored with the P system (PiCCO, V4.12; Pulsion Medical Systems AG) and the ICG system (Solar ICG module; GE Medical Systems Technology, Milwaukee, USA, 2001), to evaluate the CI. All patients received FC to optimize the haemodynamic status. Haemo- dynamic measurements were made before and after FC with colloids (5 ml/kg in 30 min). Statistical analysis was performed with Spearman nonparametric correlation and the Bland–Altman test. Results Twenty samples of data were collected. The CI P mean ± SD was 3.91 ± 0.83 l/min/m2 before FC and 3.32–8.52 l/min/m2 after FC. The mean CI ICG value before FC was 3.44 ± 0.99 l/min/m2 (2.10–5.50) and was 4.56 ± 1.37 l/min/m2 after FC. The correlation coefficient found was 0.526 (P < 0.05) and 0.588 after. The 95% CI was 0.149–0.804. The overall mean CI P – CI ICG difference The APACHE II score was 26-36 (30 ± 5). They were all moni- tored with the P system (PiCCO, V4.12; Pulsion Medical Systems AG) and the ICG system (Solar ICG module; GE Medical Systems Technology, Milwaukee, USA, 2001), to evaluate the CI. All patients received FC to optimize the haemodynamic status. Haemo- dynamic measurements were made before and after FC with colloids (5 ml/kg in 30 min). Statistical analysis was performed with Spearman nonparametric correlation and the Bland–Altman test. Results Twenty samples of data were collected. The CI P mean ± SD was 3.91 ± 0.83 l/min/m2 before FC and 3.32–8.52 l/min/m2 after FC. The mean CI ICG value before FC was 3.44 ± 0.99 l/min/m2 (2.10–5.50) and was 4.56 ± 1.37 l/min/m2 after FC. The correlation coefficient found was 0.526 (P < 0.05) and 0.588 after. The 95% CI was 0.149–0.804. Measurement of intrathoracic blood volume by lithium dilution: comparison with thermodilution The overall mean CI P – CI ICG difference The APACHE II score was 26-36 (30 ± 5). They were all moni- tored with the P system (PiCCO, V4.12; Pulsion Medical Systems AG) and the ICG system (Solar ICG module; GE Medical Systems Technology, Milwaukee, USA, 2001), to evaluate the CI. All patients received FC to optimize the haemodynamic status. Haemo- dynamic measurements were made before and after FC with colloids (5 ml/kg in 30 min). Statistical analysis was performed with Spearman nonparametric correlation and the Bland–Altman test. Methods Ethics approval was obtained. Nonpregnant adult patients on the ICU with PiCCO monitoring were recruited. Consent was given by patients’ representatives. Simultaneous calibration of PiCCO and LiDCO systems with one lithium dilution curve and the average of three thermal dilution curves allowed comparison of results. Results Twenty samples of data were collected. The CI P mean ± SD was 3.91 ± 0.83 l/min/m2 before FC and 3.32–8.52 l/min/m2 after FC. The mean CI ICG value before FC was 3.44 ± 0.99 l/min/m2 (2.10–5.50) and was 4.56 ± 1.37 l/min/m2 after FC. The correlation coefficient found was 0.526 (P < 0.05) and 0.588 after. The 95% CI was 0.149–0.804. The overall mean CI P – CI ICG difference Results Six patients were studied (five males, one female). All were intubated but none were receiving muscle relaxation. Mean age was 60.6 ± 21.8 years. The mean APACHE II score was 20.8 ± 2.3. Ten paired results were obtained (see Table 1). The S121 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin (range: 19.5–48.0 kg/m2)). CO values during the observation time ranged from 2.4 to 9.3 l/min. Bland–Altman analysis revealed a mean bias ± 2SD (limits of agreement) of 0.20 ± 2.3 l/min for FCO–ICO, 0.3 ± 2.7 l/min for PCO–ICO and 0.3 ± 2.5 l/min for CCO–ICO. Mean bias ± 2SD was –3.6 ± 59.2% for δ FCO– δ ICO, –1.6 ± 67.1% for δ PCO–δ ICO and 2.5 ± 58.8% for δ ICO– δ CCO. was 0.70 l/min/m2, with ±1.96 SD of –2.53 and 3.23, respectively. One measurement (5%) extended beyond the lower SD limit. P300 2. Spiess B, Patel M, Soltow L: Comparison of bioimpedance versus thermodilution cardiac output during cardiac surgery: evaluation of a second-generation bioimpedance device. J Cardiothor Vasc Anesth 2001, 15:567-573. 2. Spiess B, Patel M, Soltow L: Comparison of bioimpedance versus thermodilution cardiac output during cardiac surgery: evaluation of a second-generation bioimpedance device. J Cardiothor Vasc Anesth 2001, 15:567-573. Flow Trac™ cardiac output determination correlates with echocardiography Flow Trac™ cardiac output determination correlates with echocardiography F Turani, M Falco, A De Chiara, A Belli, C Parisi, A Marineli Aurelia European Hospital, Rome, Italy Critical Care 2007, 11(Suppl 2):P300 (doi: 10.1186/cc5460) 3. Kunst A, Bakker J: Electrical impedance tomography in the assessment of extravascular lung water in noncardiogenic acute respiratory failure. Chest 1999, 116:1695-1702. 3. Kunst A, Bakker J: Electrical impedance tomography in the assessment of extravascular lung water in noncardiogenic acute respiratory failure. Chest 1999, 116:1695-1702. g References 1. Bindels A, Meinders A: Pulmonary artery wedge pressure and extravascular lung water in patients with acute cardio- genic pulmonary edema requiring mechanical ventilation. Am J Cardiol 1999, 84:1158-1163. 1. Bindels A, Meinders A: Pulmonary artery wedge pressure and extravascular lung water in patients with acute cardio- genic pulmonary edema requiring mechanical ventilation. Am J Cardiol 1999, 84:1158-1163. P299 Introduction A new device may be used in intensive care to measure the cardiac output (CO) by arterial pulse pressure waveform analysis, but few studies have evaluated the reliability of this method and the correlation with other methods of CO deter- mination. The aims of this study were to evaluate the CO obtained using the Flow Trac™ Vigileo™ and the correlation with CO obtained by transthoracic echocardiography (TTE). Clinical evaluation of the FloTrac/Vigileo system and two established methods for continuous cardiac output monitoring in patients undergoing cardiac surgery Clinical evaluation of the FloTrac/Vigileo system and two established methods for continuous cardiac output monitoring in patients undergoing cardiac surgery References 1. Manecke G: Edwards FloTrac sensor and vigileo monitor; easy, accurate, reliable cardiac output assessment using the arterial pulse wave. Expert Rev Med Devices 2005, 2:523-527. 2. Opdam HI, Wan L, Bellomo R: A pilot assessment of the FloTrac™ cardiac output monitoring system. Intensive Care Med 2006 [Epub ahead of print]. Measurement of intrathoracic blood volume by lithium dilution: comparison with thermodilution The EVLW index ranges from 3.3 to 13.7 (7.86 ± 3.27) ml/kg before FC and 3.4 to 15.1 (8.58 ± 3.52) ml/kg after FC (P = 0.015). The TFC before FC was 34–60 (43 ± 10) ml/kg and 32–64 (46 ± 10) ml/kg after FC (P = 0.011). The correlation coefficient found before FC is 0.798 (P = 0.007) with 95% CI 0.656–0.940. The correlation coefficient found after FC is 0.802 (P = 0.005) with 95% CI 0.661–0.943. was 0.70 l/min/m2, with ±1.96 SD of –2.53 and 3.23, respectively. One measurement (5%) extended beyond the lower SD limit. The EVLW index ranges from 3.3 to 13.7 (7.86 ± 3.27) ml/kg before FC and 3.4 to 15.1 (8.58 ± 3.52) ml/kg after FC (P = 0.015). The TFC before FC was 34–60 (43 ± 10) ml/kg and 32–64 (46 ± 10) ml/kg after FC (P = 0.011). The correlation coefficient found before FC is 0.798 (P = 0.007) with 95% CI 0.656–0.940. The correlation coefficient found after FC is 0.802 (P = 0.005) with 95% CI 0.661–0.943. Conclusion These results indicate that the FloTrac/Vigileo system is a reliable alternative to PiCCO and the pulmonary artery catheter for CO measurement in cardiac surgery patients. Conclusions The main findings in this study are the great discrepancy between the two methods. CI measurements obtained with the ICG system underestimated CI when compared with the P system, particularly after FC. The TFC and EVLW index trends derived from FC appear similar; TFC measurements obtained with the ICG system show good correlation when compared with the EVLW index of the P system and it may be a useful index of pulmonary overloading, if supported by further randomized clinical trials. Conclusions The main findings in this study are the great discrepancy between the two methods. CI measurements obtained with the ICG system underestimated CI when compared with the P system, particularly after FC. The TFC and EVLW index trends derived from FC appear similar; TFC measurements obtained with the ICG system show good correlation when compared with the EVLW index of the P system and it may be a useful index of pulmonary overloading, if supported by further randomized clinical trials. D Button, C Hofer Triemli City Hospital, Zurich, Switzerland Triemli City Hospital, Zurich, Switzerland y p Critical Care 2007, 11(Suppl 2):P299 (doi: 10.1186/cc5459) y y Materials and methods Ten critical care patients admitted to a general ICU were enrolled in the study. All patients were mechanically ventilated (tidal volume 6–8 ml/kg, plateau pressure < 30 cmH2O) and connected to an integrated monitoring system (Flow Trac™/Vigileo™; Ewdards Lifescience, Irvine, CA, USA) that attaches to an arterial cannula. After haemodynamic stabilization the CO was calculated from an arterial pressure-based algorithm that utilises the relationship between pulse pressure and stroke volume. At the same time a TTE examination was performed (Hewlett Packard, SONO 1000) and the CO was calculated by Doppler measurement of the left ventricular outflow area (LVOT) and the velocity–time integral (VTI LVOT), assuming stroke volume = cross-sectional area x VTI. Every patient had two CO determinations by TTE during Flow Trac™ measurement. A regression analysis and Bland–Altman analysis were used to compare the two methods of CO determination. Introduction A new arterial pressure waveform analysis device, which does not need external calibration (FloTrac/Vigileo; Edwards Lifesciences, Irvine, CA, USA), became recently available for cardiac output (CO) measurement. However, only limited validation data for this technique are so far available [1,2]. Objective The aim of this study was to compare cardiac output assessed by the FloTrac/Vigileo system (FCO), the PiCCOplus system (PCO) [1] (Pulsion Medical Systems; Munich, Germany) and continuous cardiac output (CCO) monitoring using a pulmo- nary artery catheter (Vigilance; Edwards Lifesciences) with inter- mittent pulmonary artery thermodilution (ICO) in cardiac surgery patients. Methods With ethics committee approval and written patient informed consent, patients undergoing elective cardiac surgery were studied. The CCO, FCO and PCO were recorded in the perioperative period after induction of anaesthesia (= study initiation) and 1, 4, 8, 12 and 24 hours post initiation. At each measurement point the ICO was assessed as mean of three repeated bolus injections. Statistical analysis was done using Bland–Altman analysis of absolute CO values and of percentage changes (δ) between consecutive CO measurements (= trend analysis). Results A total of 40 CO determinations were performed in 10 patients. Table 1 reports the main results. Table 1 (abstract P300) R2 P Bias SD of bias CO Flow Trac™/CO TTE 0.85 <0.0001 0.24 0.45 Conclusion CO measurements obtained by Flow Trac™ show agreement with CO TTE with no clear bias, but comparative studies with thermodilution are warranted. P301 P301 P302 P302 CeVOX for continuous central venous oxygenation measurement in patients undergoing off-pump coronary artery bypass grafting A Rist, S Schneider, P Fodor, L Weibel, A Zollinger, C Hofer Triemli City Hospital, Zurich, Switzerland Critical Care 2007, 11(Suppl 2):P302 (doi: 10.1186/cc5462) A survey of cardiac output monitoring in intensive care units CeVOX for continuous central venous oxygenation measurement in patients undergoing off-pump coronary artery bypass grafting A survey of cardiac output monitoring in intensive care units R Green1, J Craig1, B Kyle1, M Jonas2 1Poole General Hospital, Poole, UK; 2Southampton General Hospital, Southampton, UK Critical Care 2007, 11(Suppl 2):P301 (doi: 10.1186/cc5461) R Green1, J Craig1, B Kyle1, M Jonas2 1Poole General Hospital, Poole, UK; 2Southampton Gen A Rist, S Schneider, P Fodor, L Weibel, A Zollinger, C Hofer Triemli City Hospital, Zurich, Switzerland Critical Care 2007, 11(Suppl 2):P302 (doi: 10.1186/cc5462) al Care 2007, 11(Suppl 2):P301 (doi: 10.1186/cc5461) Introduction We surveyed adult ICUs, looking at cardiac output monitor use with a view to demonstrating a practice change over the last 3 years. Objective The aim of this study was to compare central venous O2 saturation (ScvO2) [1] measured continuously by the CeVOX (Pulsion Medical System, Munich, Germany) device (CScvO2) with ScvO2 determined by blood gas co-oximetry (BScvO2). Method The senior physicians on ICUs in the South of England were surveyed via telephone. Information was collected as to which cardiac output monitors were available for use, which was their first choice and how often they measured cardiac output in severe sepsis. Methods Twenty-five patients undergoing elective off-pump coronary artery bypass grafting were studied during operation (OP) and during their ICU stay (ICU). OP/ICU measurement started after in vivo calibration of CeVOX. BScvO2 and CScvO2 readings were recorded at intervals of 30 minutes during OP and 120 minutes during ICU. Bland–Altman analysis and Pearson correlation was performed for overall OP, overall ICU, consecutive measurements during OP ≤1 hour, 1–2 hours and 2–3 hours after initial calibration (OP1–OP3, respectively) as well as during ICU ≤4 hours, 4–8 hours, 8–12 hours and 12–16 hours after re- calibration (ICU1–ICU4, respectively). Results Forty-nine out of 52 ICUs units contacted completed the survey. Monitor availability can be seen in Figure 1 and use in severe sepsis compared with 2003 can be seen in Table 1. D Button, C Hofer Table 1 (abstract P300) R2 P Bias SD of bias CO Flow Trac™/CO TTE 0.85 <0.0001 0.24 0.45 Conclusion CO measurements obtained by Flow Trac™ show agreement with CO TTE with no clear bias, but comparative t di ith th dil ti t d Table 1 (abstract P300) R2 P Bias SD of bias CO Flow Trac™/CO TTE 0.85 <0.0001 0.24 0.45 Results One hundred and eighty-five matched sets of data were available for statistical analysis from 31 patients (ASA III, male/ female ratio = 26/5, mean ± SD age = 66.58 ± 0.53 years (range: 45–84 years), mean ± SD body mass index = 28.2 ± 5.3 kg/m2 Conclusion CO measurements obtained by Flow Trac™ show agreement with CO TTE with no clear bias, but comparative studies with thermodilution are warranted. Conclusion CO measurements obtained by Flow Trac™ show agreement with CO TTE with no clear bias, but comparative studies with thermodilution are warranted. Conclusion CO measurements obtained by Flow Trac™ show agreement with CO TTE with no clear bias, but comparative studies with thermodilution are warranted. S122 Available online http://ccforum.com/supplements/11/S2 Figure 1 (abstract P301) Results Five hundred and nine matched sets of data were obtained; the BScvO2/CScvO2 range was 36–98.9%/46.5–99.0%, respectively. Overall mean bias ± 2SD was –1.2 ± 13.8% for CScvO2–BScvO2 during OP and –2.6 ± 16.2% during ICU. The correlation coefficient (r2) for CScvO2 vs BScvO2 was 0.614 (OP) and 0.174 (ICU). Statistics for OP1–OP3 were comparable, whereas mean bias ± 2SD increased and r2 decreased during ICU1–ICU4 (Table 1). Conclusions The results indicate that ScvO2 can be reliably assessed by CeVOX. In order to maintain accurate measurements, scheduled re-calibrations at intervals <12 hours are mandatory. Reference 1. Respiration 2001, 685:279-285. Relative influence of hypoxemia and anemia on the measurement of central venous oxygen saturation Relative influence of hypoxemia and anemia on the measurement of central venous oxygen saturation F Valenza, S Froio, L Fagnani, S Coppola, M Maffioletti, A Sicignano, E Riva, S Sibilla, L Gattinoni Fondazione IRCCS Ospedale Maggiore Policlinico Mangiagalli Regina Elena, Milano, Italy Critical Care 2007, 11(Suppl 2):P304 (doi: 10.1186/cc5464) Methods Lithium indicator dilution and pulse power analysis were used to measure cardiac output and to calculate DO2I (LiDCO- plus system). We prospectively evaluated the oxygen delivery pattern and perfusion variables of 26 high-risk patients (LiDCO group) submitted to major surgeries and goal-directed therapy during surgery and 8 hours postoperatively, aiming to maximize the DO2I to levels higher than 600 ml/min/m2 using dobutamine and either ‘restrictive’ (4 ml/kg/min) or ‘liberal’ (12 ml/kg/min) strategies of intraoperative fluid management (partial results). Postoperatively both groups received 1.5 ml/kg/min lactated ringer. Fluid challenge with 250 ml colloid was done in the presence of signs of hypovolemia and additional fluids were given if necessary. Patients were considered responders if they achieved the therapeutic goal. A historical group of 42 high-risk surgical patients in whom the therapeutic goals were to keep a mean arterial pressure between 80 and 110 mmHg, a central venous pressure between 6 and 12 cmH2O, hematocrit > 30% and urine output > 0.5 ml/kg/hour in the first 24 hours after ICU admission was used as control. Introduction Central venous oxygen saturation (ScvO2) is frequently used as a surrogate measurement of adequacy of perfusion. However, ScvO2 is also affected by arterial oxygen saturation (SpO2), oxygen consumption, and hemoglobin (Hb) according to the formula: ScvO2 = SpO2 – (VO2 / Q*1/Hb). The aim of this study was to investigate the relative influence of hypoxemia and anemia on the measurement of ScvO2. Methods A database of 700 pairs of arterial and central venous blood gases drawn from 300 patients admitted to the ICU of a university hospital was considered. After assessing for the technical adequacy of sampling (defined as a discrepancy of hematocrit and blood glucose between arterial and venous samples lower than 5%), 462 couples were selected for analysis. Samples were then clustered according to ScvO2: <70% (low), ≥70% (high). SpO2, partial pressure of oxygen (PaO2) and Hb were considered. Venous to arterial difference of partial pressure of CO2 (DpCO2), arterial to venous difference of oxygen content (DavO2) and the oxygen extraction ratio (ER) were also considered as measures of perfusion adequacy. P303 Incidence of low central venous oxygen saturation after standard postoperative intensive care management Introduction Targeted early postoperative management of high- risk surgical patients has been reported to be associated with a lower rate of complications and shorter hospital length of stay (HLOS) compared with conventional management. A low postoperative central venous oxygen saturation (ScVO2) has also been shown to be associated with higher rates of complications and of HLOS for high-risk surgical patients. Benefit from early goal- directed therapy would be unlikely if ‘standard’ postoperative management resulted in a low incidence of patients with a low ScVO2 in the early postoperative period. S123 Table 1 (abstract P302) OP1 OP2 OP3 ICU1 ICU2 ICU3 ICU4 Mean bias ± 2SD (%) –0.2 ± 13.9 +1.3 ± 9.6 +1.8 ± 16.6 –0.1 ± 12.0 –0.6 ± 15.4 –0.5 ± 13.8 –4.6 ± 16.9 r2 (P value) 0.580 (<0.001) 0.616 (<0.001) 0.513 (<0.001) 0.416 (<0.001) 0.514 (<0.001) 0.310 (0.001) 0.030 (0.247) ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin As expected, DpCO2, DavO2 and ER were different between high and low ScvO2 groups (P < 0.001). However, while Hb was similar (P = 0.670), SpO2 and PaO2 were significantly lower when ScvO2 was below 70% (P < 0.001). Normalization of ScvO2 to SpO2 (ScvO2/SpO2) allowed one to overcome the effects of hypoxemia. Values were: 0.662 (0.603–0.693) in the low group and 0.794 (0.757–0.828) in the high group (P < 0.001). Conclusions When considering ScvO2 as a surrogate measure of perfusion adequacy, it is mandatory to consider the relative effect of hypoxemia. Anemia was less relevant in our case mix. As expected, DpCO2, DavO2 and ER were different between high and low ScvO2 groups (P < 0.001). However, while Hb was similar (P = 0.670), SpO2 and PaO2 were significantly lower when ScvO2 was below 70% (P < 0.001). Normalization of ScvO2 to SpO2 (ScvO2/SpO2) allowed one to overcome the effects of hypoxemia. Values were: 0.662 (0.603–0.693) in the low group and 0.794 (0.757–0.828) in the high group (P < 0.001). Methods Arterial and central venous blood gas analysis was done on admission (T1) and after 8 hours (T2) of admission to the ICU. The HLOS and the incidence of complications were determined for patients with low (<70%) or normal (≥70%) ScVO2. Results Sixty-three postoperative patients were screened and 23 patients were analysed. Relative influence of hypoxemia and anemia on the measurement of central venous oxygen saturation Differences between low and high ScvO2 samples were estimated by Mann–Whitney rank sum test (Sigma Stat, SPSS), accepting P < 0.05 as significant. Data are presented as median (25th–75th percentile). P305 Oxygen delivery optimization using lithium indicator dilution and pulse power analysis during major surgery in high-risk patients S Lobo1, N Oliveira1, F Lobo1, E Rezende2, B Borges1, G Cunrath1, J Silva2, L Ronchi1 1Faculdade de Medicina de São José do Rio Preto, Brazil; 2Hospital do Servidor Público, São Paulo, Brazil Critical Care 2007, 11(Suppl 2):P305 (doi: 10.1186/cc5465) Conclusion A significant proportion of patients had a low ScVO2, which was associated with increased HLOS. The results provide a basis for the trial of postoperative early goal-directed therapy for high-risk surgical patients admitted to our ICU. Introduction Increasing oxygen delivery in high-risk surgical patients led to a dramatic reduction in both mortality and morbidity. Yet, it is still not widely practised due to logistical difficulties asso- ciated with its use. We aimed to evaluate whether pulse power analysis calibrated by the lithium dilution technique, a pragmatic minimally invasive technique, can be used to optimize the oxygen delivery index (DO2I) in high-risk patients during major surgery. Introduction Increasing oxygen delivery in high-risk surgical patients led to a dramatic reduction in both mortality and morbidity. Yet, it is still not widely practised due to logistical difficulties asso- ciated with its use. We aimed to evaluate whether pulse power analysis calibrated by the lithium dilution technique, a pragmatic minimally invasive technique, can be used to optimize the oxygen delivery index (DO2I) in high-risk patients during major surgery. P303 Patients were excluded if they did not have a central line positioned in the superior vena cava or blood had not been sampled at both time points. Patients with pre-ICU HLOS > 5 days (n = 10), acute spinal cord injury (n = 3), or admitted for postoperative airway management (n = 4) were omitted. ScVO2 was low in 7/23 patients at T2 and six of these had lower gastrointestinal surgery. The HLOS (median (IQR)) was longer in those with low ScVO2 at T2 (17 (37.8) v 9.5 (5.0) days, P = 0.04). The incidence of complications was not different. There were no differences between the ScVO2 groups at T2 with respect to age, gender, standard base excess, lactate, haemoglobin, mean arterial pressure or central venous pressure. The volume of colloid the two groups received in the 8-hour observation period was not different although there was a trend for the low group to receive more crystalloid (P = 0.08). Conclusions When considering ScvO2 as a surrogate measure of perfusion adequacy, it is mandatory to consider the relative effect of hypoxemia. Anemia was less relevant in our case mix. Figure 1 (abstract P305) Results ScvO2 was 62.5% (56.3–66.2) in the low group (n = 180), 76.7% (73.6–80.7) in the high group (n = 282). In the low group values were: SpO2 95.0% (95.1–98.3), PaO2 72.0 mmHg (59.5–112.5), DpCO2 8 mmHg (6–9), DavO2 4.3 ml/100 ml (3.4–5.2), ER 0.346 (0.310–0.399), Hb 9.9 g/dl (8.9–11.1). In the high group values were: SpO2 98.3% (96.2–99.5), PaO2 106.5 mmHg (81.0–167.0), DpCO2 6 mmHg (4–7), DavO2 2.9 ml/ 100 ml (2.3–3.6), ER 0.215 (0.185–0.250), Hb 9.9 g/dl (8.7–11.1). S124 Available online http://ccforum.com/supplements/11/S2 Table 1 (abstract P305) Control LiDCO Age 60 ± 17 68 ± 10 Lact1 3.5 ± 1 2.6 ± 1 Lact2 2.7 ± 1 1.9 ± 1 ScvO2-1 64 ± 18 75 ± 10 ScvO2-2 68 ± 13 72 ± 14 Complications (%) 50 15 Deaths (%) 26 7.7 Table 1 (abstract P305) correlation between Lac and RQ (R = 0.66; P < 0.01) was found. For a DO2 < 9 ml/kg, SvO2 did not correlate with Lac. Opposite, a direct correlation between Lac and RQ (R = 0.81; P < 0.01) was found. The DO2/VCO2 ratio showed an inverse relationship with Lac (R = –0.75; P < 0.01). ROC curves to predict Lac+ were constructed. The areas under the ROC curves were 0.40, 0.74, and 0.81 for SvO2, RQ, and DO2/VCO2 ratio, respectively. An optimal cutoff value of 3.1 (sensitivity = 0.70, specificity = 0.77) was determined for the DO2/VCO2 ratio predicting the presence of Lac+. Conclusions Our findings showed that, for a DO2 > 9 ml/kg, the SVO2, RQ, and DO2/VCO2 ratio may be used interchangeably. For a DO2 < 9 ml/kg, the DO2/VCO2 ratio seems a more reliable predictor of AM than SvO2 and RQ. The DO2/VCO2 ratio can be simply and quickly calculated at the bedside because pulse wave analysis allows the DO2 to be frequently calculated, and because the CO2 analyzer provides VCO2 values continuously. Combined gas exchange and pulse wave monitoring might be a valuable and a useful approach to detect AM in trauma patients. Results Median doses of 10 µg/kg/min and 7.5 µg/kg/min dobutamine were used intraoperatively and postoperatively, respec- tively. A total of 75% and 84% of the patients were responders during surgery and postoperatively. However, a much better pattern of DO2I during surgery was seen in the liberal group than in the restrictive group (Figure 1). P306 Methods In this prospective, intervention and response study, 30° PLR of both legs was performed in 20 supine patients receiving mechanical ventilation after elective cardiothoracic surgery. The thermodilution cardiac output (COtd), heart rate, central venous pressure (CVP), MAP, PP, SP and SVV measurements were performed before, during and after PLR. Oxygen delivery to carbon dioxide production ratio for continuously detecting anaerobic metabolism in trauma patients F Franchi1, S Scolletta1, E Casadei1, P Mongelli2, B Biagioli1, P Giomarelli1 1University of Siena, Italy; 2Policlinico Le Scotte, Siena, Italy Critical Care 2007, 11(Suppl 2):P306 (doi: 10.1186/cc5466) Oxygen delivery to carbon dioxide production ratio for continuously detecting anaerobic metabolism in trauma patients Results The COtd, MAP, CVP, PP and SP increased after PLR. No change in heart rate and systemic vascular resistance was observed. We found a significant correlation between PLR- induced changes in COtd versus SVV during baseline (slope = 0.902, P = 0.003), changes in MAP (slope = 0.499, P = 0.003), PP (slope = 0.190, P = 0.024) and SP (slope = 0.276, P = 0.021). Changes in CVP were not correlated to changes in COtd. The area under the receiver operating curves was larger than 0.7 but not different for MAP, PP, SP and SVV. Introduction Lactate levels have been shown to correlate with tissue hypoxia. Unfortunately, due to their slow clearance, lactate levels may not reflect the actual metabolic condition. Under tissue hypoxia the carbon dioxide production (VCO2) should be less reduced than the oxygen consumption, and the respiratory quotient (RQ) should increase. The oxygen delivery (DO2)/VCO2 ratio could be used as an indicator of anaerobic metabolism (AM) since it reflects the oxygen demand and delivery, and the tissue oxygenation. We tested the DO2/VCO2 ratio as a potential predictor of AM in trauma patients. Conclusion Not only baseline SVV but also PLR-induced changes in MAP, PP and SP are reliable parameters to assess preload dependence in cardiac surgery patients. In the clinical setting we prefer the MAP approach, based on simplicity, availability and robustness. Methods Eighty consecutive adult trauma patients were pros- pectively studied. The DO2, VCO2, RQ, DO2/VCO2 ratio, SvO2, and arterial lactate (Lac) values were collected at ICU admission. The DO2 was calculated using the cardiac index measured by a pulse contour system (Hemoscan). The VCO2 was measured under steady-state conditions using a CO2 analyzer (930 Siemens Elema). Passive leg raising-induced changes in mean radial artery pressure can be used to assess preload dependence Passive leg raising-induced changes in mean radial artery pressure can be used to assess preload dependence B Geerts, R de Wilde, P van den Berg, J Jansen Leiden University Medical Centre, Leiden, The Netherlands Critical Care 2007, 11(Suppl 2):P307 (doi: 10.1186/cc5467) Introduction We evaluated whether changes in, routinely measured, mean radial artery pressure (MAP) due to passive leg raising (PLR) can be used to assess preload dependence in nonspontaneous breathing patients. We therefore compared the changes in cardiac output (CO) with changes in MAP, pulse pressure (PP) and systolic pressure (SP) as well as the stroke volume variation (SVV) before PLR. Conclusion The use of a therapeutic approach guided by DO2I calculated by the LiDCO plus system, intraoperatively and postoperatively, seems to be a feasible and practical approach to guide oxygen delivery optimization therapy during major surgery in high-risk patients. Better perfusion and a much lower rate of complications were seen in optimized patients. P306 The presence of AM (for example, hyperlactatemia, Lac+) was defined by an increase in Lac >2 mmol/l. Correlation analysis and the ROC test were applied. A Sami, S Abdellatif, R Nasri, H Ksouri, S Ben Lakhal Rabta Hospital, Tunis, Tunisia Critical Care 2007, 11(Suppl 2):P308 (doi: 10.1186/cc5468) Figure 1 (abstract P305) The values for arterial lactate and central venous oxygen saturation (ScvO2) on ICU admission and 24 hours later for both groups are shown in Table 1. Significantly lower arterial lactate and higher ScvO2 were seen in optimized patients (P < 0.05 vs control group). Major complications occurred in 50% of the patients in the historical control group (21/42) and in 15% of the LiDCO group (4/26) (RR 0.15, 95% CI 0.037–0.600, P < 0.05). P307 Passive leg raising-induced changes in mean radial artery pressure can be used to assess preload dependence B Geerts, R de Wilde, P van den Berg, J Jansen Leiden University Medical Centre, Leiden, The Netherlands Critical Care 2007, 11(Suppl 2):P307 (doi: 10.1186/cc5467) References 1. Kakkos SK, et al.: Int Angiol 2005, 24:330-335. 2. Kakkos SK, et al.: J Vasc Surg 2005, 42:296-303. Introduction The new sequential leg compression device (SCD) (Tyco, Mansfield, MA, USA) pneumatically applies sequential compression to the lower limb, while maintaining a pressure gradient throughout the compression cycle [1,2]. We hypothesized that the SCD Response System could shift blood volume toward the thoracic compartment comparable with a volume challenge, with an increase in preload index such as the intrathoracic blood volume index (ITBVI) and stroke volume index (SVI). The aim of the study was to evaluate the relationships between changes in SVI (∆SVI) induced by SCD and ∆SVI induced by rapid fluid loading (RFL) in critically ill patients. 1. Kakkos SK, et al.: Int Angiol 2005, 24:330-335. 2. Kakkos SK, et al.: J Vasc Surg 2005, 42:296-303. 1. Kakkos SK, et al.: Int Angiol 2005, 24:330-335. 2. Kakkos SK, et al.: J Vasc Surg 2005, 42:296-303. 1. Kakkos SK, et al.: Int Angiol 2005, 24:330-335. 2. Kakkos SK, et al.: J Vasc Surg 2005, 42:296-303. P309 Changes in stroke volume and intrathoracic blood volume induced by a sequential leg compression in critically ill patients. Conclusions The SCD Response System could shift blood volume toward the thoracic compartment comparable with RFL better in mechanically ventilated than in spontaneously breathing patients. Larger population studies are needed to confirm these preliminary data. M Costa, R Casaretti, M Tuccillo, L Girardi, P Chiarandini, G Della Rocca University of Udine, Italy Critical Care 2007, 11(Suppl 2):P309 (doi: 10.1186/cc5469) University of Udine, Italy P308 Figure 2 (abstract P309) Figure 2 (abstract P309) Discussion Patients with low ∆PP seem to be of poor prognosis because they have a low BCL, a low maximum cortisol increase after the ACTH test, and a high death rate. Annane and colleagues [1] found that nonsurvivors have low MAP, high lactate level, high basal cortisol level and low maximum cortisol level increase after the test compared with survivors. This finding is in contrast to our patients. index, ITBVI, and SVI were recorded in the supine position before and after treatment with the SCD Express Compression System®. The same data where collected before and after a RFL performed with 3 ml/kg hydroxyethyl starch 6%. The relationships between ∆SVI induced by SCD and ∆SVI induced by RFL were analyzed by linear regression analysis. Statistical significance was considered to be at P <0.05. Conclusion Patients with low ∆PP before realizing the ACTH test tend to have more probability of adrenal deficiency, have more probability to receive corticosteroid and have poor prognosis. Reference 1. Annane et al.: JAMA 2000, 283:1038-1045. Results Linear regression analysis between ∆SVI induced by SCD (∆SCD) and ∆SVI induced by RFL (∆RFL) showed r2 = 0.50 (P = 0.0002). When analyzed in a subgroup of spontaneously breathing versus mechanically ventilated patients, the relationships observed were respectively r2 = 0.41 (P < 0.01) (Figure 1) and r2 = 0.73 (P < 0.007) (Figure 2). P308 Pulse pressure variation and adrenal insufficiency in septic shock Results For a threshold value of DO2 > 9 ml/kg, Lac showed an inverse relationship with SvO2 (R = –0.84; P < 0.01) and DO2/VCO2 ratio (R = –0.73; P < 0.01). Conversely, a direct Introduction It is known that corticosteroid therapy improves the hemodynamic state in patients with septic shock and relative S125 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Figure 1 (abstract P309) Figure 2 (abstract P309) Figure 1 (abstract P309) adrenal insufficiency. This effect is partially due to a direct action on vascular tone in the more vasoplegic patient, so they may be more hypovolemic. We tried in this study to determine whether pulse pressure variation measured just before the adreno- corticotropin test can predict the adrenal state. Methods During a period of 3 years (January 2001–December 2003) we realized a prospective observational study. All patients having septic shock were enrolled. Patients with arrhythmia were excluded. We measured hemodynamic data (mean arterial pressure (MAP), pulse pressure variation (∆PP)), then we realized an ACTH short test (injection of 250 mg ACTH with dosage of the cortisol level before the injection, at 30 and 60 minutes). Results One hundred and one patients were enrolled. Age was 48 ± 17 years. SAPS II = 45 ± 16, APACHE II score = 18 ± 8, MAP = 52 ± 12 mmHg, lactate = 3.5 ± 2 mmol/l, and basal cortisol level (BCL) = 278 ± 143 µg/l. We divided all patients into two groups using the ∆PP cutoff: <12% (n = 30) and ≥12% (n = 71). There is no difference in the two groups in age, SAPS II, and MAP. Patients with low ∆PP (<12%) have a significantly (P = 0.01) low BCL: 204 ± 127 µg/l vs 291 ± 133 µg/l, a low increase of cortisol level in response to ACTH: 264 ± 144 µg/l vs 369 ± 142 µg/l (P = 0.02), and a low maximum variation after the ACTH test: 59 ± 52 µg/l vs 79 ± 63 µg/l (not significant). The relative adrenal deficiency (∆max < 90 µg/l) is more frequent in patients with low ∆PP: 80% vs 60%. Survival is lower in the low ∆PP group, 13% vs 40%. P312 Results Respiratory variation in POP waveform amplitude could accurately predict variation in arterial PP with a sensibility of 83.3%, specificity of 85.7%, positive predictive value (PPV) of 71.4 and negative predictive value (NPV) of 92.3. The area under the ROC curve was 0.88 (0.79–0.97) with a best cutoff value of 14% to predict a variation in arterial PP of 13%. The kappa index of agreement was 0.65 (P < 0.001). Eighteen (30%) patients had variations in arterial PP above 13%, and 21 (35%) showed variations in POP waveform amplitude above 14%. In patients without ALI (P/F > 300) the sensibility was 100%, specificity was 93.3%, NPV was 100% and PPV was 80%. In the group with ALI (P/F < 300) the kappa index measure of agreement was 0.55, and in the group without ALI the kappa index was 0.85. PEEP levels were not different between the groups. P311 Assessing fluid responsiveness in patients undergoing abdominal major surgery: a comparison of the respiratory systolic variation test and other indices A Bisoffi Varani1, A Martini1, N Menestrina2, A Russo3, L Gottin1 1Policlinico GB Rossi, Verona, Italy; 2Hopital Erasme, Verona, Italy; 3Romano D’Ezzelino Vicenza, Italy Critical Care 2007, 11(Suppl 2):P311 (doi: 10.1186/cc5471) Assessing fluid responsiveness in patients undergoing abdominal major surgery: a comparison of the respiratory systolic variation test and other indices Results The mean baseline FTc was 278 ms, and the mean target FTc was 405 ms. The mean average blood loss was 3.77 l/patient. The mean preoperative urea and creatinine were 5.9 mmol/l and 95.3mmol/l, respectively. The mean 24-hour postoperative urea and creatinine were 5.23 mmol/l and 76.77 mmol/l, respectively. See Figure 1. A Bisoffi Varani1, A Martini1, N Menestrina2, A Russo3, L Gottin1 1Policlinico GB Rossi, Verona, Italy; 2Hopital Erasme, Verona, Italy; 3Romano D’Ezzelino Vicenza, Italy Critical Care 2007, 11(Suppl 2):P311 (doi: 10.1186/cc5471) Conclusion Goal-directed intraoperative fluid therapy aiming for FTc of 375–425 ms as a target improved the 24-hour Introduction Fluid responsiveness can be predicted by respiratory-induced changes in arterial blood pressure. In this study we compare the predictive performance of various haemodynamic parameters, including the respiratory systolic variation test (RSVT), pulse pressure variation (DPP) and stroke volume variation (SVV), in 18 patients undergoing abdominal major surgery. Figure 1 (abstract P312) Goal-directed intraoperative fluid therapy improved postoperative renal functions in aortic surgical patients M Soliman, S Bajaj, K Ismail Department of Anaesthesia and Intensive Care Medicine, The Mid Yorkshire Hospitals, UK Critical Care 2007, 11(Suppl 2):P312 (doi: 10.1186/cc5472) Introduction Goal-directed intraoperative fluid therapy reduced the hospital stay after major surgery [1]. Aortic vascular surgery is associated with excessive blood loss and massive fluid shift [2]. We found that postoperative urea and creatinine improved when intravascular fluid volume was maintained using transoesophageal Doppler. Conclusion Respiratory variation in arterial PP above 13% can be accurately predicted by a variation in POP waveform amplitude of 14% with good correlation and agreement. Our results confirm the findings of a recent trial and suggest that the correlation is even stronger when ALI is absent. These findings raise potential clinical applications of respiratory variation in POP waveform amplitude for haemodynamic management of patients without an arterial catheter. Methods We randomly selected 40 patients who underwent elective infrarenal aortic surgery (aortic aneurysm repair/aorto- bifemoral grafting). All patients’ cardiac output was continuously monitored using a transoesophageal Doppler probe (EDM™; Deltex Medical, Inc., Irving, TX, USA). The corrected flow time (FTc) was recorded immediately after induction as a baseline and recorded again pre-extubation. A target FTc of 375–425 ms was aimed for. The estimated total blood loss was calculated for each patient at the end of surgery. Preoperative and 24-hour postoperative urea and creatinine were recorded for comparison. Methods We randomly selected 40 patients who underwent elective infrarenal aortic surgery (aortic aneurysm repair/aorto- bifemoral grafting). All patients’ cardiac output was continuously monitored using a transoesophageal Doppler probe (EDM™; Deltex Medical, Inc., Irving, TX, USA). The corrected flow time (FTc) was recorded immediately after induction as a baseline and recorded again pre-extubation. A target FTc of 375–425 ms was aimed for. The estimated total blood loss was calculated for each patient at the end of surgery. Preoperative and 24-hour postoperative urea and creatinine were recorded for comparison. Results The mean baseline FTc was 278 ms, and the mean target FTc was 405 ms. The mean average blood loss was 3.77 l/patient. The mean preoperative urea and creatinine were 5.9 mmol/l and 95.3mmol/l, respectively. The mean 24-hour postoperative urea and creatinine were 5.23 mmol/l and 76.77 mmol/l, respectively. See Figure 1. Respiratory pulse oximetry plethysmographic waveform amplitude correlates with arterial pulse pressure variations The kappa of agreement was 0.65 (P < 0.001). Eighteen (30%) patient variations in arterial PP above 13%, and 21 (35%) sh variations in POP waveform amplitude above 14%. In pa without ALI (P/F > 300) the sensibility was 100%, specificity 93.3%, NPV was 100% and PPV was 80%. In the group wit (P/F < 300) the kappa index measure of agreement was 0.55 in the group without ALI the kappa index was 0.85. PEEP were not different between the groups. Conclusion Respiratory variation in arterial PP above 13% ca accurately predicted by a variation in POP waveform amplitu 14% with good correlation and agreement. Our results confir findings of a recent trial and suggest that the correlation is stronger when ALI is absent. These findings raise potential c applications of respiratory variation in POP waveform amplitud haemodynamic management of patients without an arterial cath P311 Assessing fluid responsiveness in patients undergoing abdominal major surgery: a comparison of the respirat systolic variation test and other indices A Bisoffi Varani1, A Martini1, N Menestrina2, A Russo3, L Go 1Policlinico GB Rossi, Verona, Italy; 2Hopital Erasme, Verona, 3Romano D’Ezzelino Vicenza, Italy Critical Care 2007, 11(Suppl 2):P311 (doi: 10.1186/cc5471) Introduction Fluid responsiveness can be predicted respiratory-induced changes in arterial blood pressure. In this we compare the predictive performance of various haemodyn parameters including the respiratory systolic variation test (R Conclusion Functional parameters are superior to static indicators of cardiac preload in predicting the response to fluid administration. DPP and SVV, with their suggested threshold value, can predict fluid responsiveness in patients undergoing major abdominal surgery. The RSVT may be a more accurate predictor of fluid responsiveness although its performance demands a complex respiratory manoeuvre and is dependent on offline measurement and calculations, which limits its clinical use. Methods Sixty patients were included in the study. Thirty-nine (65%) had diagnosis of ALI and 21 (35%) had normal gas exchange, defined as a relation of PaO2 to FiO2 (P/F) below and above 300, respectively. Respiratory variation in arterial PP and POP waveform amplitude were recorded simultaneously on a beat- to-beat basis, and mean values of two measures for each parameter were compared for correlation and agreement. Respiratory pulse oximetry plethysmographic waveform amplitude correlates with arterial pulse pressure variations These findings raise applications of respiratory variation in POP wavefor haemodynamic management of patients without an a P311 Assessing fluid responsiveness in patients un abdominal major surgery: a comparison of th systolic variation test and other indices A Bisoffi Varani1, A Martini1, N Menestrina2, A Ru 1Policlinico GB Rossi, Verona, Italy; 2Hopital Erasme 3Romano D’Ezzelino Vicenza, Italy Critical Care 2007, 11(Suppl 2):P311 (doi: 10.1186 Introduction Fluid responsiveness can be respiratory-induced changes in arterial blood pressu we compare the predictive performance of various parameters, including the respiratory systolic variat pulse pressure variation (DPP) and stroke volume in 18 patients undergoing abdominal major surgery Methods Eighteen patients, ASA I–II, were underg surgery (whipple resection). The heart rate (HR) pressure (CVP), arterial pressure (AP), cardiac cardiac index (CI), stroke volume (SV), stroke volu SVV, DPP and RSVT were measured before and load of 7 ml/kg hydroxyethylstarch. (CO, CI, SV, SV displayed by the Edwards Vigileo monitor with F Receiving-operating characteristic (ROC) curves w each parameter to evaluate its predicting valu correlation between the baseline value of between preoperative values of DPP, SVV and RSVT and percentage changes in SVI after volume load (better than the values of HR, AP, CVP). amplitude, as they both depend on the stroke volume. We designed a prospective study to evaluate the correlation between respiratory arterial PP variation and POP waveform amplitude variations in ventilated patients and the influence of acute lung injury (ALI) in this relationship. amplitude, as they both depend on the stroke volume. designed a prospective study to evaluate the correlation bet respiratory arterial PP variation and POP waveform amp variations in ventilated patients and the influence of acute injury (ALI) in this relationship. Methods Sixty patients were included in the study. Thirty (65%) had diagnosis of ALI and 21 (35%) had norma exchange, defined as a relation of PaO2 to FiO2 (P/F) below above 300, respectively. Respiratory variation in arterial PP POP waveform amplitude were recorded simultaneously on a to-beat basis, and mean values of two measures for parameter were compared for correlation and agreement. Results Respiratory variation in POP waveform amplitude accurately predict variation in arterial PP with a sensibil 83.3%, specificity of 85.7%, positive predictive value (PP 71.4 and negative predictive value (NPV) of 92.3. The area u the ROC curve was 0.88 (0.79–0.97) with a best cutoff val 14% to predict a variation in arterial PP of 13%. Respiratory pulse oximetry plethysmographic waveform amplitude correlates with arterial pulse pressure variations Respiratory pulse oximetry plethysmographic waveform amplitude correlates with arterial pulse pressure variations G Penna, M Kalichsztein, G Nobre, F Braga, J Kezen, P Kurtz, P Rosa Casa de Saude Sao Jose, Rio de Janeiro, Brazil Critical Care 2007, 11(Suppl 2):P310 (doi: 10.1186/cc5470) Methods Twenty-seven patients (mean age 60 ± 9.1 years) admitted to the ICU were studied. Each patient received conventional monitoring plus hemodynamic–volumetric monitoring (PiCCO System; Pulsion Medical Systems, Munich, Germany). The heart rate, mean arterial pressure, central venous pressure, cardiac Introduction Arterial pulse pressure (PP) respiratory variation is a good predictor of fluid responsiveness in ventilated patients. Recently, it has been shown that variation in PP may correlate with variation in pulse oximetry plethysmographic (POP) waveform S126 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 amplitude, as they both depend on the strok designed a prospective study to evaluate the corre respiratory arterial PP variation and POP wave variations in ventilated patients and the influence injury (ALI) in this relationship. Methods Sixty patients were included in the st (65%) had diagnosis of ALI and 21 (35%) h exchange, defined as a relation of PaO2 to FiO2 ( above 300, respectively. Respiratory variation in POP waveform amplitude were recorded simultane to-beat basis, and mean values of two meas parameter were compared for correlation and agree Results Respiratory variation in POP waveform a accurately predict variation in arterial PP with 83.3%, specificity of 85.7%, positive predictive 71.4 and negative predictive value (NPV) of 92.3. the ROC curve was 0.88 (0.79–0.97) with a best 14% to predict a variation in arterial PP of 13%. T of agreement was 0.65 (P < 0.001). Eighteen (30% variations in arterial PP above 13%, and 21 variations in POP waveform amplitude above 14 without ALI (P/F > 300) the sensibility was 100%, 93.3%, NPV was 100% and PPV was 80%. In the (P/F < 300) the kappa index measure of agreemen in the group without ALI the kappa index was 0.8 were not different between the groups. Conclusion Respiratory variation in arterial PP abo accurately predicted by a variation in POP wavefo 14% with good correlation and agreement. Our res findings of a recent trial and suggest that the cor stronger when ALI is absent. Analysis of physiological functions of different human serum albumin pharmaceutical preparations Analysis of physiological functions of different human serum albumin pharmaceutical preparations M Di Giambattista, L Mascio, T Branckaert, R Laub Central Department for Fractionation, Red Cross, Brussels, Belgium Critical Care 2007, 11(Suppl 2):P313 (doi: 10.1186/cc5473) Aims and methods A clinical scenario was used to assess current knowledge among medical staff regarding i.v. fluid therapy. ‘An 85- year-old lady is brought into A&E semiconscious. Temperature 32°C, blood pressure 90/50 mmHg and BM 6.5 mmol/l. Arterial blood gases (ABG) on room air: pH 7.12 pO2 10.8 kPa, pCO2 2.6 kPa, HCO3 – 12 mmol/l, O2 saturation 94% and base excess –19’. Medical staff were asked to complete a questionnaire relating to the case under supervised conditions. Introduction New information is emerging as a basis for reconsidering albumin as a key homeostatic molecule in the critically ill. We are only beginning to understand the full spectrum of albumin properties and action in healthy individuals and hypoalbuminaemic patients. Besides its function in the regulation of colloidal osmotic pressure, albumin has an important antioxidant capacity and a role in the transport of a wide range of drugs, hormones, ions, amino acids, and fatty acids. Few comparative studies have as yet been performed, and they address only a restricted number of parameters mostly defined by the European Pharmacopeia. Results Eighty-seven questionnaires were completed by seven SpR/consultants, 48 F2/senior house officers, 13 F1 and 19 final- year medical students. ABG interpretation was correct in 80/87 (92%). Only 52/87 (59.8%) could calculate the anion gap and only 1/87 listed fluid as a cause of a metabolic acidosis. Eighty-three staff (93.4%) knew that a metabolic acidosis caused an increased respiratory rate. Normal saline was the first-choice fluid for resuscitation in almost 60% (52/87) cases. The chloride concentration of normal saline was known by 12/87 staff (13.8%). The serum chloride concentration was known by 28/87 staff (32%). Conclusion The majority of medical staff prescribe normal saline as their first-choice intravenous fluid. Many medical staff are unaware of the electrolyte composition of normal saline, the phenomenon of hyperchloraemic metabolic acidosis, or how to differentiate hyperchloraemic metabolic acidosis from lactic acidosis by calculating the anion gap. A good understanding of fluid therapy is important for all medical staff. Objective To study and compare the main albumin functions of eight preparations of pharmaceutical-grade albumin, using a battery of different techniques. Saline-induced hyperchloraemic metabolic acidosis: an unrecognised phenomenon among medical staff? 1. Gan et al.: Goal-directed intraoperative fluid administration reduces length of hospital stay after major surgery. Anes- thesiology 2002, 97:820-826. A Turley, B Bose, J Gedney The James Cook University Hospital, Middlesbrough, UK Critical Care 2007, 11(Suppl 2):P314 (doi: 10.1186/cc5474) 2. Miyashita T, et al.: An analysis of risk factors of periopera- tive bleeding in surgical repair of abdominal aortic aneurysm. J Cardiovasc Surg 2000, 41:595-599. Introduction Hyperchloraemic acidosis is well recognised within critical care, is implicated in the development of organ dysfunction and is an important consequence of administration of large volumes of chloride-containing intravenous (i.v.) fluid, such as normal (0.9%) saline [1,2]. Within most hospitals, junior medical staff with differing levels of experience prescribe the majority of i.v. fluid therapy. Analysis of physiological functions of different human serum albumin pharmaceutical preparations Two additional albumin prepara- tions, a preparation without stabilisers and a recombinant albumin from Pichia pastoris, were also included in the study. Methods The following biochemical and physicochemical parameters were investigated: total protein concentration (Biuret assay) and albumin antigen (nephelometry); quantitative analysis of contaminating proteins by nephelometry, levels of polymers and fragments by gel filtration chromatography on Superose 6, the binding affinity of exogenous ligands for Sudlow’s site I (warfarin) or site II (dansylsarcosine) by steady-state spectrofluorimetry, the reactivity of Cys34 with Ellman’s reagent, and the esterase-like activity using p-nitrophenyl acetate as substrate by spectro- photometry. References 1. Wilkes NJ: Anesth Analg 2001, 93:811-816. 2. McFarlane C, Lee A: Anaesthesia 1994, 49:779-781. 1. Wilkes NJ: Anesth Analg 2001, 93:811 816. 2. McFarlane C, Lee A: Anaesthesia 1994, 49:779-781. Results All pharmaceutical-grade products show a purity ranging from 95% to 108%. The main contaminant proteins are prealbumin, transferrin, α-1 acid glycoprotein, haptoglobulin, and retinol-binding protein. All of them are in conformity with the European Pharmacopeia specifications. The warfarin-binding capacity of the 10 albumin preparations was studied. An average binding constant of 2.6 (±0.3) x 105 M–1 (n = 1) was found. The presence of stabilisers reduced the binding of dansylsarcosine significantly (by 27–40%). The esterase-like activity toward p- nitrophenyl acetate and the reactivity of Cys34 differed from product to product. Interesting is the absence of free Cys34 in the recombinant albumin. Figure 1 (abstract P312) S127 Methods Eighteen patients, ASA I–II, were undergoing pancreatic surgery (whipple resection). The heart rate (HR) central venous pressure (CVP), arterial pressure (AP), cardiac output (CO), cardiac index (CI), stroke volume (SV), stroke volume index (SVI), SVV, DPP and RSVT were measured before and after a volume load of 7 ml/kg hydroxyethylstarch. (CO, CI, SV, SVI and SVV were displayed by the Edwards Vigileo monitor with FloTrac sensor.) Receiving-operating characteristic (ROC) curves were plotted for each parameter to evaluate its predicting value. In addition, correlation between the baseline value of haemodynamic parameters RSVT, DPP, SVV and change in SVI after volume administration was made. Results DPP, SVV and RSVT demonstrate a good predicting value (ROC area 0.870, 0.877 and 0.943 with P = 0.010, 0.009 and 0.002, respectively). A statistically significant correlation was found ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin postoperative urea urea and creatinine in 40 aortic surgical patients in spite of the excessive blood loss. postoperative urea urea and creatinine in 40 aortic surgical patients in spite of the excessive blood loss. postoperative urea urea and creatinine in 40 aortic surgical patients in spite of the excessive blood loss. P314 P315 Low-dose dopexamine (≤1 µg/kg/min) was associated with a 49% reduction in 28-day mortality (6.3% vs 12.3%; OR = 0.51 (95% CI 0.29–0.89), P = 0.008). The length of postoperative stay was also reduced in the low-dose dopexamine group compared with control (median 13 vs 15 days, HR 0.75 (95% CI 0.65–0.88), P = 0.004). High-dose dopexamine (>1 µg/kg/min) was not associated with a difference in mortality (14.5% vs 12.3%; OR = 1.18 (95% CI 0.67–2.08), P = 0.37) or length of stay (median 17 vs 15 days, HR 1.10 (95% CI 0.90–1.34), P = 0.37) when compared with controls. P317 Critical care utilisation following bariatric surgery P Whiting, A Mannings, S Reynolds, S Hutchinson, R Ackroyd Royal Hallamshire Hospital, Sheffield, UK Critical Care 2007, 11(Suppl 2):P317 (doi: 10.1186/cc5477) Critical care utilisation following bariatric surgery P Whiting, A Mannings, S Reynolds, S Hutchinson, R Ackroyd Royal Hallamshire Hospital, Sheffield, UK Critical Care 2007, 11(Suppl 2):P317 (doi: 10.1186/cc5477) Introduction Following the introduction of a new bariatric surgical service in Sheffield, we aimed to assess the impact upon critical care services and examine how this has changed as the service has evolved. Conclusions Perioperative use of low-dose dopexamine decreases mortality and duration of hospital stay in patients undergoing major surgery. R f References Method All admissions for bariatric surgery between 1 April 2003 and 30 April 2006 were reviewed retrospectively. These proce- dures were performed on two sites, the Royal Hallamshire Hospital (RHH) and Thornbury Hospital (TH). The critical care admissions and length of hospital stay (LOS) were reviewed. References 1. Boyd O, et al.: JAMA 1993, 270:2699-2707. 2. Wilson J, et al.: BMJ 1999, 318:1099-1103. 3. Takala J, et al.: Crit Care Med 2000, 28:3417-3423. 4. Stone MD, et al.: Br J Anaesth 2003, 91:619-624. 5. Pearse R, et al.: Crit Care 2005, 9:687-693. 1. Boyd O, et al.: JAMA 1993, 270:2699-2707. 2. Wilson J, et al.: BMJ 1999, 318:1099-1103. 3. Takala J, et al.: Crit Care Med 2000, 28:3417-3423. 4. Stone MD, et al.: Br J Anaesth 2003, 91:619-624. Results A total of 497 patients were identified as having had bariatric surgery. After review of hospital and critical care admission data, a total of 473 were identified with complete data. Of these, 94 (19.9%) were open procedures (OP), 260 (55.0%) laparoscopic bandings (LB) and 119 (25.1%) laparoscopic gastric bypasses (LGB). The age range was 16–68 years. P315 An individual patient meta-analysis of clinical trials using dopexamine to increase oxygen delivery in high-risk surgical patients J Belsey1, R Pearse2, J Cole3, D Bennet4 1JB Medical Ltd, Sudbury, UK; 2The Royal London Hospital, London, UK; 3Cephalon UK, Stevenage, UK; 4St George’s Hospital, London, UK Critical Care 2007, 11(Suppl 2):P315 (doi: 10.1186/cc5475) Introduction Postoperative outcomes may be improved if cardiac output and oxygen delivery are maintained at optimal levels. Trials of the use of dopexamine for this purpose have yielded inconsistent results. This may relate to the use of high doses in some trials. A meta-analysis of data from these trials may therefore identify a benefit of low-dose dopexamine on postoperative mortality and length of stay. Introduction Postoperative outcomes may be improved if cardiac output and oxygen delivery are maintained at optimal levels. Trials of the use of dopexamine for this purpose have yielded inconsistent results. This may relate to the use of high doses in some trials. A meta-analysis of data from these trials may therefore identify a benefit of low-dose dopexamine on postoperative mortality and length of stay. Conclusion Significant differences were observed between the 10 different human albumin preparations, recombinant or not. We confirm that the presence of stabilisers such as tryptophan derivatives significantly reduces the binding capacity of Sudlow’s site II. Two important physiological properties of albumin, the esterase-like and antioxidant activities, were also found to be modified to different extents in all pharmaceutical-grade products in comparison with the albumin without stabiliser. The benefits of albumin administration should be considered carefully, taking into account the different functions and properties of albumin. Methods A comprehensive literature review was performed to identify published randomised trials of perioperative dopexamine infusion in patients undergoing major surgery. Individual patient S128 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 between inflection point and systolic foot: mean ± SD = 40.0 ± 9.4 ms, intrasubject SD 4.6 ms). Retrograde coronary blood flow during isovolumic ventricular contraction may be the origin of the persistent end-diastolic pressure and distension perturbation. This study shows that the duration of the isovolumic contraction can be reliably extracted from the carotid artery distension waveform. data were obtained, allowing a meta-regression approach to explore mortality outcomes after correction for age and dose of dopexamine. A Cox proportional hazards model was constructed to examine the length of stay. Results Five studies fulfilled the inclusion criteria [1-5]. P315 The average hospital LOS for OP was 6.8 days, for LGB 4.0 days and for LB 1.9 days. Surgical procedures and HDU admissions increased annually (2003–2006) from 74 to 249, and 21 to 107, respec- tively. As a proportion, open procedures declined from 60% to 7%, and laparoscopic interventions increased (LB from 40% to 63% and LGB from 0% to 30%). There were a total of 14 admissions to the ITU by 10 patients, of which seven had undergone an initial OP. No admissions were elective and eight patients required further surgical interventions. HDU admissions occurred on both sites, with 148/277 (53.4%) of patients admitted to HDU at TH, and 53/196 (27.6%) at RHH. At TH only three patients required level 2 care, and 95 were discharged within 26 hours. At RHH, 16 patients required level 2 care, and 38 were discharged within 26 hours. 5. Pearse R, et al.: Crit Care 2005, 9:687-693. 5. Pearse R, et al.: Crit Care 2005, 9:687-693. Figure 1 (abstract P316) Figure 1 (abstract P316) The onset of ventricular isovolumetric contraction as reflected in the carotid artery distension waveform The onset of ventricular isovolumetric contraction as reflected in the carotid artery distension waveform The onset of ventricular isovolumetric contraction as reflected in the carotid artery distension waveform M van Houwelingen, A Hoeks, R Reneman University of Maastricht, The Netherlands Critical Care 2007, 11(Suppl 2):P316 (doi: 10.1186/cc5476) M van Houwelingen, A Hoeks, R Reneman University of Maastricht, The Netherlands Critical Care 2007, 11(Suppl 2):P316 (doi: 10.1186/cc5476) The blood pressure waveform carries information about the cardiac contraction and the impedance characteristics of the vascular bed. Here, we demonstrate that the start of isovolumic ventricular contraction is persistently reflected as an inflection point in the pressure wave as recorded in the aortic root (TPIC) as well as in the carotid artery distension waveform (TDIC) as it travels down the arterial tree. In a group of six patients with normal pressure gradients across the aortic valve after valve replacement, the TPIC had a small delay with respect to the onset of isovolumic ventricular contraction (<10 ms). In a group (n = 21) of young, presumably healthy, volunteers, the inflection point occurred persistently in the carotid distension waveform, as recorded by means of ultrasound, before the systolic foot (intersubject delay Discussion The requirement for ITU admission in this surgical group is, and has remained, low, despite a significant increase in bariatric surgical procedures. This increase is predominantly laparoscopic surgery. HDU activity has increased as the service has expanded; however, 90.4% of this is level 1 care, particularly at TH, where admission to the HDU is a matter of policy rather than clinical necessity. Availability of a level 1 facility would significantly decrease the requirement for HDU provision – an important consideration when introducing a new bariatric service. Figure 1 (abstract P316) Abdominal pressure volume determinants Abdominal pressure volume determinants J Mulier, B Dillemans, K Verbeke, A Luijten AZ Sint Jan AV Brugge, Belgium Critical Care 2007, 11(Suppl 2):P320 (doi: 10.1186/cc5480) The abdominal pressure–volume relation can be described by a linear relation giving an elastance (E) and a pressure at zero volume (PV0). The goal of this study was to measure this relation in a large group of patients with different characteristics looking for the factors that influence and explain this relation. It is believed that obese persons have higher abdominal pressures and it is unclear whether muscle relaxation lowers it. A large group of 70 patients, ASA class I or II, between 21 and 75 years old and scheduled for laparoscopic surgery were included in this study with approval from the hospital ethical committee. Results CPAP determined a reduction of portal vein velocity: 30.0 ± 9.1 cm/s vs 19.7 ± 5.0 cm/s (P = 0.01). IVC diameters are increased by CPAP: inspiratory diameter 9.49 ± 2.5 cm vs 12.05 ± 3.9 cm (P = 0.002), expiratory diameter 16.46 ± 2.9 cm vs 18.08 ± 3.65 cm (P = 0.05). Anaesthesia was induced with propofol 200 mg, sufentanil 20 µg, and sevoflurane 1.5 Mac in 50% O2/N2O. Some patients were fully muscle relaxed with nimbex 20 mg while others not. Patients were asked to empty the bladder before surgery. The stomach was emptied by suction through a gastric tube. An Olympus insufflator UHI-3 was initialised and the abdomen was inflated with a stepwise flow to 7, 10, 13 and 16 mmHg. When the pressure was reached, flow was stopped and the actual pressure and volume measured giving four data points. E and PV0 were calculated by fitting to a linear relation. The following recorded determinants were evaluated by regression analysis for their effect: age, length, weight, BMI, sex, gravidity and muscle relaxation. Conclusions The results of this study demonstrate that, in healthy subjects, variation of intrathoracic pressure by CPAP influences venous return. HF reduction could be due to an increased IVC pressure, as displayed by the bigger diameters measured during CPAP, other than a diaphragmatic descent. Ultrasonography is able to detect this effect and could be useful in a more complete evaluation of patient haemodynamic status in various clinical settings. Intrathoracic pressure effects on hepatic flow and inferior vena cava diameter: an ultrasonographic study A Graziani, E Gamberini, B Praticò, F Morgagni, F Savelli, S Bonarelli Oospedale Maurizio Bufalini, Cesena, Italy Critical Care 2007, 11(Suppl 2):P318 (doi: 10.1186/cc5478) Objective To compare the effect of an increased intrathoracic pressure on the inferior vena cava (ICV) diameter and hepatic flow (HF) in healthy subjects. S129 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Patients and methods Ten healthy subjects (seven females, three males; age 27.3 ± 4.5 years) were investigated in a supine position before and after application of continuous positive airways pressure (CPAP) of 10 cmH2O by nasal mask. The study was performed using sonographic equipment with a multiprobe (convex 3.5–5 MHz; sector 2.5–3.5 MHz) and color-Doppler capability (Hitachi H 21). IVC was visualized by a two-dimensional echographic sector probe and M-mode was used to measure the inspiratory and expiratory diameters at the origin of the supra- hepatic veins. HF is composed of portal flow (PF) and hepatic artery flow (HAF). Portal velocity, assessed near the liver hilum, was used as a measure of PF, and the left intrahepatic branch resistivity index (RI) was used as a measure of HAF. Measures were repeated twice for each value of intrathoracic pressure by two different examiners and the mean value was given for the statistical analysis. Results are given as the mean ± SD. Data were evaluated by paired t test and P < 0.05 was taken as statistically significant. Conclusion Development of IAH significantly increases the risk of death in patients with severe sepsis or septic shock, but not in nonseptic patients. Conclusion Development of IAH significantly increases the risk of death in patients with severe sepsis or septic shock, but not in nonseptic patients. Intra-abdominal hypertension as a risk factor of death in patients with severe sepsis or septic shock Intra-abdominal hypertension as a risk factor of death in patients with severe sepsis or septic shock Table 1 (abstract P320) PV0 E Age 0.838 0.003 Length 0.356 0.245 Weight 0.012 0.294 BMI 0.054 0.272 Sex 0.596 0.536 Gravidity 0.305 0.049 Relaxation 0.001 0.376 A Reintam1, P Parm2, R Kitus2, H Kern3, J Starkopf2 1East Tallinn Central Hospital, Tallinn, Estonia; 2Tartu University Clinics, Tartu, Estonia; 3DRK Kliniken Berlin, Germany Critical Care 2007, 11(Suppl 2):P319 (doi: 10.1186/cc5479) Introduction Critically ill patients with severe sepsis or septic shock have a very high mortality rate. The aim of our study was to investigate the impact of intra-abdominal hypertension (IAH) on the outcome of patients with or without severe sepsis/septic shock. Introduction Critically ill patients with severe sepsis or septic shock have a very high mortality rate. The aim of our study was to investigate the impact of intra-abdominal hypertension (IAH) on the outcome of patients with or without severe sepsis/septic shock. Methods Two hundred and fifty-three mechanically ventilated patients admitted to the general ICU of Tartu University Hospital were prospectively studied. Patients who had severe sepsis or septic shock at admission or developed it during their first week of stay were compared with patients not suffering from severe sepsis. IAH was defined as sustained intra-abdominal pressure above or equal to 12 mmHg developing within the first week in the ICU. Results Severe sepsis or septic shock was observed in 123 patients (48.6%). The ICU mortality among these patients was 33.3% compared with 18.5% in nonseptic patients (P = 0.005). IAH developed in 95 patients (37.0%). The incidence of IAH was higher among septic patients (45.5% vs 28.5%, P = 0.004). Those septic patients who developed IAH had a mortality rate of 50.0% compared with 19.4% in septic patients without IAH (P < 0.001). Mortality among nonseptic patients was not different between the patients with or without IAH (18.9% vs 18.3%). Development of IAH was a significant risk factor for death in septic patients (OR 4.15; 95% CI 1.87–9.26), but not in nonseptic patients (OR 1.04; 95% CI 0.39–2.77). Methods Two hundred and fifty-three mechanically ventilated patients admitted to the general ICU of Tartu University Hospital were prospectively studied. Patients who had severe sepsis or septic shock at admission or developed it during their first week of stay were compared with patients not suffering from severe sepsis. P319 PV0 increases significantly with body weight and decreases significantly with muscle relaxation. Intra-abdominal hypertension as a risk factor of death in patients with severe sepsis or septic shock IAH was defined as sustained intra-abdominal pressure above or equal to 12 mmHg developing within the first week in the ICU. P323 Results and discussion We treated 624 CPA patients in the past 2 years, 38% were cardiac and 62% were noncardiac aetiology (3% subarachnoid haemorrhage and 5% acute aortic dissection). Restricted in cardiac aetiology patients, 13% showed a ventricular fibrillation (VF) as a first monitored rhythm and 33% showed a VF during resuscitation. In all patients, 50% of VF were witnessed. In witnessed patients, 17% were witnessed by the ELST during transfer and 81% by a layperson, most of whom are patients' families and patients’ friends. Fifty-three per cent were witnessed in the patients' home (35% in patients’ private room, 1% in bathroom and 7% in lavatory), 4% in an aged people’s residence, 1% in a hotel, restaurant, office, and 3% on the road. Only 48% of CPA patients underwent bystander CPR, and 51% of witnessed CPA patients (24% of all CPA patients) underwent bystander CPR by the witness; most patients underwent bystander CPR in the patients’ home by the patients’ families. Vasopressin alone or with epinephrine may be superior to epinephrine in asystolic out-of-hospital cardiac arrest: an observational study M Ðpindler, Ð Grmec, Ð Mally Center for Emergency Medicine Maribor, Slovenia Critical Care 2007, 11(Suppl 2):P323 (doi: 10.1186/cc5483) Background In patients undergoing cardiopulmonary resusci- tation, circulating endogenous vasopressin concentrations were significantly higher in successfully resuscitated patients than in patients who died. Clinical data considering vasopressin to be an equivalent option to epinephrine in cardiopulmonary resuscitation (CPR) are limited. The studies of out-of-hospital cardiac arrest (OHCA) confirm an increasing part of asystole as the initial rhythm. The hypothesis of this study was that vasopressin improves the rate of return of spontaneous circulation (ROSC) and the survival rate in asystolic OHCA, when used early in the resuscitation effort. Methods This was a prospective cohort study, with a historic group compared trial set in an urban emergency medical services system, serving a population of 200,000. All nonpregnant, normothermic adults (>18 years) suffering nontraumatic OHCA with asystole were eligible. We compared two treatment groups of resuscitated patients with OHCA. In the epinephrine group (EPI) patients received epinephrine 1 mg i.v. every 3 minutes only. In the vasopressin group (VASO) patients received arginine vasopressin 40 IU i.v. only or followed by epinephrine 1 mg every 3 minutes during CPR. Statistics. Exact Fisher test, Wilcoxon rank-sum test, and analysis of independent predictors with multivariate logistic regression were used; P < 0.05. P321 P321 Bystander CPR for out-of-hospital cardiac arrest in Japan Y Moriwaki, M Sugiyama, H Toyoda, T Kosuge, M Iwashita, J Ishikawa, S Matsuzaki, Y Tahara, N Suzuki Yokohama City University Medical Center, Yokohama, Japan Critical Care 2007, 11(Suppl 2):P321 (doi: 10.1186/cc5481) P321 Bystander CPR for out-of-hospital cardiac arrest in Japan Y Moriwaki, M Sugiyama, H Toyoda, T Kosuge, M Iwashita, J Ishikawa, S Matsuzaki, Y Tahara, N Suzuki Yokohama City University Medical Center, Yokohama, Japan Critical Care 2007, 11(Suppl 2):P321 (doi: 10.1186/cc5481) q g p g Results Severe sepsis or septic shock was observed in 123 patients (48.6%). The ICU mortality among these patients was 33.3% compared with 18.5% in nonseptic patients (P = 0.005). IAH developed in 95 patients (37.0%). The incidence of IAH was higher among septic patients (45.5% vs 28.5%, P = 0.004). Those septic patients who developed IAH had a mortality rate of 50.0% compared with 19.4% in septic patients without IAH (P < 0.001). Mortality among nonseptic patients was not different between the patients with or without IAH (18.9% vs 18.3%). Development of IAH was a significant risk factor for death in septic patients (OR 4.15; 95% CI 1.87–9.26), but not in nonseptic patients (OR 1.04; 95% CI 0.39–2.77). Background and aims The aim of this study is to clarify how Japanese citizens are interested in the importance of immediate cardiopulmonary resuscitation (CPR) and defibrillation, and how they understand that importance. In Japan, the out-of-hospital emergency medical service system has been established with the ambulance service and an emergency life saving technician (ELST) belonging to the fire department. Subjects and methods Patients’ records were reviewed for the past 2 years. In Yokohama (3,700,000 people), the cardio- S130 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 pulmonary arrest (CPA) patient is transferred to the nearest ED of the selected 11 hospitals with adequate ability of CPR and cerebral resuscitation. We perform ultrasound, chest X-ray, and blood examination including Troponin in all CPA patients, and cerebral plane CT (40%) or chest CT (7%). CT was not performed in patients with a clearly known aetiology. coagulation system may contribute to reperfusion disorders and possibly affect the outcome of these patients. Further studies need to show whether elevation of the D-dimer level in patients after CPR could be a prognostic marker. P323 Conclusions In Japan, CPA patients were witnessed mainly in their home by their families or their friends. The aetiology of some CPA patients is noncardiac (subarachnoid haemorrhage or acute aortic dissection, etc.). However, only 24% CPA patients underwent bystander CPR by the witness. D-Dimer level and outcome in patients after cardiopulmonary resuscitation The plasma D- dimer level was measured immediately after admission to the ICU. Conclusions Vasopressin was superior to epinephrine in patients with asystole (better ROSC with admission, 24-hour survival and discharge from hospital). Vasopressin followed by epinephrine was more effective than epinephrine alone in the treatment of refractory cardiac arrest. D-Dimer level and outcome in patients after cardiopulmonary resuscitation H Busch, A Geibel, C Bode, T Schwab UKL Freiburg, Germany Critical Care 2007, 11(Suppl 2):P322 (doi: 10.1186/cc5482) Background Clinical and experimental studies have demonstrated a marked activation of blood coagulation and fibrin formation after prolonged cardiopulmonary resuscitation (CPR). Several experimental studies suggest that thrombolysis therapy acts directly on thrombi or emboli but also enhances microcirculatory reperfusion. In this retrospective study we investigated the extent of blood coagulation and fibrin formation via the plasma D-dimer level, an indicator of endogenous fibrinolytic activity, in patients who underwent inhospital and out-of-hospital cardiac arrest from nontraumatic causes. Results The investigators enrolled 227 consecutive patients: in the EPI group 183 patients (years 2001–2003) and in the VASO group 44 patients (year 2004). Baseline (demographic and clinical) characteristics were similar for the two groups. Comparing the EPI and VASO groups, any ROSC was achieved in 81/183 (44%) and 34/44 (77%), P = 0.04; ROSC with admission in 61/183 (33%) and 27/44 (61%), P = 0.03; 24-hour survival in 44/183 (24%) and 23/44 (52%), P = 0.01; and discharge from hospital in 17/183 (9%) and 10/44 (23%), P = 0.04. Vasopressin was an independent predictor of ROSC with admission with an odds ratio of 2.4 (95% CI = 1.24–4.98). Methods and results Forty-five patients were included from 1 January 2004 to 31 March 2005 after CPR in the case of restoration of spontaneous circulation (ROSC). The plasma D- dimer level was measured immediately after admission to the ICU. Results In 38 patients (84%) cardial reasons for cardiac arrest were found. Marked activation of blood coagulation was found in all patients. After prolonged cardiopulmonary resuscitation (ROSC not within the first 30 min) patients showed significant elevated serum D-dimer level compared with patients after ROSC in the first 30 minutes (663 µg/l vs 3,328 µg/ml, P < 0.0001; normal range <0.25 µg/ml). The time period between cardiac arrest and ROSC and plasma D-dimer level correlated significantly (r = 0.8, P < 0.01) after CPR. Patients who died showed significant elevated serum D-dimer level compared with the surviving patients (1,258 ± 1,587 µg/l vs 3,164 ± 1,974 µg/l, P = 0.026 median). The plasma D- dimer level correlated significantly to the negative outcome in these patients (r = 0.55, P < 0.01). Methods and results Forty-five patients were included from 1 January 2004 to 31 March 2005 after CPR in the case of restoration of spontaneous circulation (ROSC). P324 Vasopressin, epinephrine, and methylprednisolone in inhospital cardiac arrest S Mentzelopoulos, N Katsios, A Papastylianou, S Gisioti, A Stathopoulos, E Stamataki, C Roussos, S Zakynthinos Evaggelismos Hospital, Athens, Greece Critical Care 2007, 11(Suppl 2):P324 (doi: 10.1186/cc5484) Introduction Combined vasopressin, epinephrine, and methyl- prednisolone during cardiopulmonary resuscitation (CPR) may improve survival in inhospital cardiac arrest. Introduction Combined vasopressin, epinephrine, and methyl- prednisolone during cardiopulmonary resuscitation (CPR) may improve survival in inhospital cardiac arrest. Conclusions Our data demonstrate a marked time-dependent activation of blood coagulation and fibrin formation after prolonged cardiac arrest and CPR in humans. These changes of the S131 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine groups; however, a striking increase was observed in patients wi bad neurologic outcome peaking after 24 hours (16.7 ± 30.0 vs 6 ± 2.1 µg/l; P < 0.013). PCT values after 24 hours were the be predictor for a bad neurologic outcome with an area under th curve of 0.91 (cutoff value: 0.44; sensitivity 100%/specificity 62% Conclusion TNFα, IL-6 and IL-8 serum levels are significant Figure 1 (abstract P324) Figure 1 (abstract P325) Figure 1 (abstract P324) groups; however, a striking increase was observed in patients with bad neurologic outcome peaking after 24 hours (16.7 ± 30.0 vs 6.9 ± 2.1 µg/l; P < 0.013). PCT values after 24 hours were the best predictor for a bad neurologic outcome with an area under the curve of 0.91 (cutoff value: 0.44; sensitivity 100%/specificity 62%). Conclusion TNFα IL-6 and IL-8 serum levels are significantly Figure 1 (abstract P324) Figure 1 (abstract P325) Figure 1 (abstract P325) Figure 1 (abstract P325) Figure 1 (abstract P325) Figure 1 (abstract P324) groups; however, a striking increase was observed in patients with bad neurologic outcome peaking after 24 hours (16.7 ± 30.0 vs 6.9 ± 2.1 µg/l; P < 0.013). PCT values after 24 hours were the best predictor for a bad neurologic outcome with an area under the curve of 0.91 (cutoff value: 0.44; sensitivity 100%/specificity 62%). Conclusion TNFα, IL-6 and IL-8 serum levels are significantly elevated in the early phase after successful CPR in patients with bad neurological outcome. PCT increases are subsequently found and have a high prognostic value for the neurologic outcome. P325 Introduction Mortality among patients surviving to be discharged following inhospital cardiac arrest (IHCA) is high. The present study assesses whether this might be explained by differences in patient factor or in factors at resuscitation. P326 Do patient characteristics or factors at resuscitation influence long-term outcome in patients surviving to be discharged following inhospital cardiac arrest? influence long-term outcome in patients surviving to be discharged following inhospital cardiac arrest? M Skrifvars1, M Castrén2, J Nurmi2, A Thorén3, S Aune3, J Herlitz3 1Helsinki EMS and 2Department of Anaesthesiology and Intensive Care Medicine, Helsinki University Hospital, Helsinki, Finland; 3Sahlgrenska Hospital, Gothenburg, Sweden Critical Care 2007, 11(Suppl 2):P326 (doi: 10.1186/cc5486) Results Study group patients had higher rates of ROSC (37/44 vs 24/47; P < 0.01) and discharge either to home or to a rehabilitation facility (7/44 vs 1/47; P < 0.05). Sixty-day survival was improved in the study group (Figure 1). M Skrifvars1, M Castrén2, J Nurmi2, A Thorén3, S Aune3, J Herlitz3 1Helsinki EMS and 2Department of Anaesthesiology and Intensive Care Medicine, Helsinki University Hospital, Helsinki, Finland; 3Sahlgrenska Hospital, Gothenburg, Sweden Critical Care 2007, 11(Suppl 2):P326 (doi: 10.1186/cc5486) Conclusions Combination treatment improves survival in inhospital cardiac arrest. P324 Methods Ninety-one adults with cardiac arrest were randomized to receive either vasopressin (20 IU/CPR cycle for five cycles) plus epinephrine (1 mg/CPR cycle) plus methylprednisolone (single dose = 40 mg) or placebo plus epinephrine (1 mg/CPR cycle) plus placebo. Primary endpoints were return of spontaneous circulation (ROSC) for ≥15 minutes, and survival to discharge either to home or to a rehabilitation facility. Procalcitonin is a powerful predictor of outcome after cardiopulmonary resuscitation C Stoppe, D Brücken, J Bickenbach, R Kuhlen, M Fries University Hospital Aachen, Germany Critical Care 2007, 11(Suppl 2):P325 (doi: 10.1186/cc5485) Methods An analysis of IHCA data collected from one Swedish tertiary hospital and from five Finnish secondary hospitals over a 10-year period. The study was limited to patients surviving to be discharged from the hospital. Multiple logistic regression analysis was used to identify factors associated with survival at 1 year from the arrest. Introduction We evaluated the time course and relationship of proinflammatory cytokines and procalcitonin (PCT) serum levels after cardiopulmonary resuscitation (CPR). We hypothesized that an increase of cytokine levels would precede a marked increase in PCT levels and that PCT would be the best predictor of the final neurologic outcome. Results Of a total of 1,578 resuscitated patients, 441 (28%) survived to hospital discharge and 359 (80%) were alive at 12 months. Factors associated with survival at 12 months were age (odds ratio (OR) 0.96, 95% confidence interval (CI) 0.935–0.979), no renal disease (OR 0.4, CI 0.2–0.9), good functional status at discharge (OR 2.9, CI 1.4–6.0), and arrest occurring at (compared with arrests at general wards) the emergency ward (OR 5.8, CI 1.8–18), cardiac care unit (OR 2.9, CI 1.3–6.3), ICU (OR 2.6, CI 1.1–6.2), ward for thoracic surgery (OR 12.9, CI 3.4–49.1) and unit for interventional radiology (OR 16.4, CI 4.4–61.2). There was no difference in initial rhythm, delay to defibrillation or delay to return of spontaneous circulation between survivors and nonsurvivors at 12 months. Results Of a total of 1,578 resuscitated patients, 441 (28%) survived to hospital discharge and 359 (80%) were alive at 12 months. Factors associated with survival at 12 months were age (odds ratio (OR) 0.96, 95% confidence interval (CI) 0.935–0.979), no renal disease (OR 0.4, CI 0.2–0.9), good functional status at discharge (OR 2.9, CI 1.4–6.0), and arrest occurring at (compared with arrests at general wards) the emergency ward (OR 5.8, CI 1.8–18), cardiac care unit (OR 2.9, CI 1.3–6.3), ICU (OR 2.6, CI 1.1–6.2), ward for thoracic surgery (OR 12.9, CI 3.4–49.1) and unit for interventional radiology (OR 16.4, CI 4.4–61.2). There was no difference in initial rhythm, delay to defibrillation or delay to return of spontaneous circulation between survivors and nonsurvivors at 12 months. Conclusion Several patient factors, mainly age, functional status and co-morbid disease, influence long-term survival following IHCA. Out-of-hospital surface cooling with a cooling-blanket to induce mild hypothermia in humans after cardiac arrest: a feasibility trial Methods A 77-year-old male with a history of hypertension, previous replacement of aortic valve and a right coronary artery bypass was admitted to our ICU after cardiac arrest. He suffered a collapse while walking. The emergency service arrived within 5 minutes. The initial cardiac rhythm was ventricular fibrillation. The estimated time to return to spontaneous circulation was 20 minutes. The patient arrived in the hospital 50 minutes after collapse and was immediately admitted to the ICU. Thirty minutes after ICU admission, he was unconscious with a Glasgow coma score of 5. Hypothermia was induced by the Artic Sun 2000 cooling system (Medivance, Louisville, CO, USA), and the goal temperature was obtained 105 minutes after induction. The body temperature was monitored continuously with a Foley catheter. Hypothermia was maintained for 24 hours at 33ºC and rewarming to the target temperature of 37ºC was achieved over 12 hours. No electrolyte imbalances or coagulopathies were observed. No overcooling was observed at any moment. The patient was extubated on day 6 after admission and discharged from the ICU on day 10 without neurological sequelae. T Uray1, R Malzer2, A Auer2, A Zajicek2, F Sterz1, J Arrich1, R Fleischhackl1, A Janata1, M Holzer1, A Laggner1, W Behringer1 1Medical University Vienna, Austria; 2Ambulance Service of Vienna, Austria Critical Care 2007, 11(Suppl 2):P327 (doi: 10.1186/cc5487) Introduction Mild hypothermia (32–34°C) is a promising new therapy for patients resuscitated from cardiac arrest. Animal studies suggest that early and fast cooling is crucial for beneficial effect on neurological outcome. Inducing mild hypothermia immediately after successful restoration of spontaneous circulation (ROSC) in the out-of-hospital setting remains a challenge. Therefore, a novel cooling-blanket (EMCOOLSpad®), independent of any energy source during use, was developed. The aim of the study was to evaluate feasibility and safety of out-of-hospital surface cooling with EMCOOLSpad® in patients successfully resuscitated from cardiac arrest. Conclusions Careful monitoring of temperature is important during use of therapeutic hypothermia because unintentional overcooling below 32°C may place the patient at risk for serious complications such as arrhythmias, infection, and coagulopathy. Cooling with a water-circulating cooling device is fast and safe. Clinicians should work to institute protocols for mild hypothermia treatment for such patients as a part of their critical care treatment. Methods We included patients successfully resuscitated from out- of-hospital cardiac arrest with an oesophageal temperature (Tes) >34°C. References 1. Bernard SA, Gray TW, Buist MD, et al.: Treatment of comatose survivors of out-of-hospital cardiac arrest with induced hypothermia. N Engl J Med 2002; 346:557-563. 1. Bernard SA, Gray TW, Buist MD, et al.: Treatment of comatose survivors of out-of-hospital cardiac arrest with induced hypothermia. N Engl J Med 2002; 346:557-563. 2. 2005 International Consensus on Cardiopulmonary Resuscitation (CPR) and Emergency Cardiovascular Care (ECC) Science with Treatment Recommendations. Circula- tion 2005, 112 (Suppl):III-1-III-136. Results From September 2006 to December 2006, 10 patients, weighing 70 (64–93) kg, were included in the study. Cooling was initiated 14 (7–20) minutes after ROSC. The cooling-blanket decreased the Tes from 36.5 (36.2–36.7)°C at the start of cooling to 34.0°C within 61 (47–93) minutes, and to target temperature Tes 33°C within 83 (61–119) minutes, resulting in a cooling rate of 2.6 (1.6–3.6)°C/hour. Hospital admission was 45 (40–53) minutes after ROSC, and Tes 33°C was achieved 78 (32–107) minutes after admission. In eight patients, precooled parts of the cooling- blanket had to be applied repeatedly on the chest and abdomen to maintain the target temperature of Tes 33°C for 24 hours. No skin lesions were observed. 2. 2005 International Consensus on Cardiopulmonary Resuscitation (CPR) and Emergency Cardiovascular Care (ECC) Science with Treatment Recommendations. Circula- tion 2005, 112 (Suppl):III-1-III-136. Induction of mild hypothermia in cardiac arrest survivors with cardiogenic shock syndrome Induction of mild hypothermia in cardiac arrest survivors with cardiogenic shock syndrome R Skulec, J Belohlavek, V Dytrych, T Kovarnik, M Aschermann, A Linhart Conclusion Noninvasive surface cooling with the EMCOOLSpad® immediately after resuscitation from cardiac arrest, in the out-of- hospital setting, was shown to be feasible and safe. Whether early cooling, as compared with delayed cooling in the hospital, will improve neurological outcome needs to be determined in a prospective randomized trial. Introduction Induction of mild hypothermia (MH) in patients resuscitated from cardiac arrest can improve their outcome. However, benefits and risks of MH induction in patients who remain in cardiogenic shock after the return of spontaneous circulation (ROSC) are unclear. We therefore analysed a group of all cardiac arrest survivors who were indicated for MH induction in our coronary care unit (CCU) and compared the outcome of patients with cardiogenic shock syndrome after ROSC with the outcome of those who were relatively haemodynamically stable. Procalcitonin is a powerful predictor of outcome after cardiopulmonary resuscitation Location of the arrest also influences survival, but the initial rhythm, the delays to defibrillation and return of spontaneous circulation do not. Methods Data were prospectively collected from 71 patients. Blood samples were taken after admission to the hospital and after 6, 12, 24, 72 and 120 hours. PCT, IL-6, IL-8 and TNFα levels were measured using automated assays. On day 14 patients were divided into two neurologic outcome groups according to the Cerebral Performance Categories (CPC 1–3: bad; CPC 4–5: good). Differences between groups were evaluated using a t test. ROC curves were computed to analyze the predictive value of the markers for a bad outcome. Results There was an early and significant increase in TNFα, IL-6 and IL-8 after admission to the hospital (14.4 ± 5.2, 185 ± 248 and 89 ± 81 µg/l) and in the ensuing 6 hours (15.6 ± 8.7, 209 ± 239 and 176 ± 232 µg/l) in patients with bad neurologic outcome. Initially, PCT levels were indistinguishable between the Conclusion Several patient factors, mainly age, functional status and co-morbid disease, influence long-term survival following IHCA. Location of the arrest also influences survival, but the initial rhythm, the delays to defibrillation and return of spontaneous circulation do not. S132 Available online http://ccforum.com/supplements/11/S2 P327 Nowadays, the maintenance of hypothermia can be facilitated with new technology to avoid unintentional overcooling. Nowadays, the maintenance of hypothermia can be facilitated with new technology to avoid unintentional overcooling. Out-of-hospital surface cooling with a cooling-blanket to induce mild hypothermia in humans after cardiac arrest: a feasibility trial Out-of-hospital surface cooling with a cooling-blanket to induce mild hypothermia in humans after cardiac arrest: a feasibility trial The EMCOOLSpad® consists of multiple cooling units (12 mm thick), filled with a mixture of graphite/water, which are stored in a cooling box at –3°C in the ambulance car. Cooling was initiated as soon as feasible by the first treating paramedics and emergency physicians, and was continued in the emergency room. The cooling-blanket was removed when the Tes reached 34°C. The target temperature of Tes 33°C was maintained for 24 hours. Data are presented as the median and interquartile range (25–75%). P329 Induction of mild hypothermia in cardiac arrest survivors with cardiogenic shock syndrome R Skulec, J Belohlavek, V Dytrych, T Kovarnik, M Aschermann, A Linhart General Teaching Hospital, Prague, Czech Republic Critical Care 2007, 11(Suppl 2):P329 (doi: 10.1186/cc5489) Reduction of magnetic resonance spectroscopy brain temperature by convective head cooling in healthy humans Reduction of magnetic resonance spectroscopy brain temperature by convective head cooling in healthy humans Results From 50 consecutive patients, 28 fulfilled criteria of cardiogenic shock before MH initiation (group A), and 22 were relatively hemodynamically stable (group B). While predicted mortality was 83.1 ± 13.1% in group A and 63.2 ± 19.0% in group B (P < 0.001), real inhospital mortality was 55.6% in group A and only 18.2% in group B patients (P = 0.009). The best inhospital neurological outcome was found favourable in 71.4% patients in group A and in 86.3% in group B (P = 0.306). Favourable discharge neurological outcome was reached in 100% in group A and in 94% in group B (P = 1.000). Patients in both groups did not differ in rate of complications. B Harris1, P Andrews1, I Marshall1, T Robinson2, G Murray1 1University of Edinburgh, UK; 2KCI, Ferndown, UK Critical Care 2007, 11(Suppl 2):P331 (doi: 10.1186/cc5491) This pilot study assessed the effect of forced convective head and neck cooling on brain temperature, measured by magnetic resonance spectroscopy (MRS), in five healthy adult humans (three males). Following a 10-minute baseline, subjects received 30 minutes head cooling followed by 30 minutes head and neck cooling. The cooling device delivered air at 11ºC and 15 m/s through a hood and separate neck collar made of a double layer of nylon sheeting, the inner layer pierced with holes. Subjects wore a windproof waistcoat taped round the base of their neck and were wrapped in blankets from the base of the neck down. Bilateral foot warming with chemical hot packs was used to encourage heat loss in the presence of normothermia. Conclusions While inhospital mortality in cardiac arrest survivors treated by MH was expectably higher in those with cardiogenic shock than in stable patients, favourable neurological outcome was frequent and comparable in both groups of patients. Moreover, MH application was safe in both groups. Therefore, induction of MH should be considered also in cardiac arrest survivors with cardiogenic shock syndrome after ROSC. MRS temperature data were collected at the level of the basal ganglia over the baseline and the last 10 minutes of each cooling intervention. MRS detects naturally occurring brain metabolites and interpretation of the relative frequencies of N-acetyl aspartate and water allows estimation of tissue temperature in 1 cm3 voxels. P330 P330 Changes in urinary 8-hydroxy-2-deoxyguanosine in patients with global brain ischemia undergoing brain hypothermia therapy: comparison of whole body and selective head cooling K Ikeda, Y Kuroki, K Yosikawa, T Yokoyama, H Utino Hachiouji Medical Center, Tokyo, Japan Critical Care 2007, 11(Suppl 2):P330 (doi: 10.1186/cc5490) Changes in urinary 8-hydroxy-2-deoxyguanosine in patients with global brain ischemia undergoing brain hypothermia therapy: comparison of whole body and selective head cooling Changes in urinary 8-hydroxy-2-deoxyguanosine in patients with global brain ischemia undergoing brain hypothermia therapy: comparison of whole body and selective head cooling K Ikeda, Y Kuroki, K Yosikawa, T Yokoyama, H Utino Hachiouji Medical Center, Tokyo, Japan Critical Care 2007, 11(Suppl 2):P330 (doi: 10.1186/cc5490) The mean baseline-corrected MRS brain temperature over all voxels reduced by –0.45ºC (SD 0.23ºC, P = 0.01, 5% CI –0.74 to –0.17ºC) with head cooling and –0.37ºC (SD 0.30ºC, P = 0.049, 95% CI –0.74 to 0.00ºC) with head and neck cooling. Head cooling reduced the mean baseline-corrected MRS brain temperature in core voxels in all subjects. The formal test for gradient was not significant (P = 0.43; 95% CI –0.15 to 0.29ºC). Head and neck cooling reduced the temperature in core voxels in three subjects; the test for gradient was not significant (P = 0.07; 95% CI –0.03 to 0.58ºC). The mean baseline-corrected oesophageal temperature reductions for the last 10 minutes of each intervention were –0.16ºC (SD 0.04ºC) with head cooling and –0.36ºC (SD 0.12ºC) with head and neck cooling. Introduction Oxygen free radicals play an important role in global brain ischemia after cardiac arrest. Brain hypothermia therapy is effective in suppressing free radical expression. The aim of this study was to assess free radical expression under brain hypothermia, and to compare the expression between whole body and selective head cooling. Methods The subjects were 12 patients treated with mild brain hypothermia (34 ± 1°C) after resuscitation following cardiac arrest in our ICU; five patients received whole body cooling and seven patients received selective head cooling. We examined the hemodynamic changes and the urinary concentration of 8-hydroxy- 2-deoxyguanosine (determined by HPLC) during brain hypothermia therapy. Furthermore, we compared the prognosis at 28 days after admission to the ICU. Forced convective head cooling reduced the MRS brain temperature at an equivalent of 1.35ºC per hour in healthy subjects, and the reduction was apparent across the brain. P328 Mild hypothermia induction following cardiac arrest using a water-circulating cooling device yp g g water-circulating cooling device E Miñambres, B Suberviola, A González-Castro, J San Jose, J Gutierrez Morlote Hospital Universitario Marques de Valdecilla, Santander, Spain Critical Care 2007, 11(Suppl 2):P328 (doi: 10.1186/cc5488) Methods We performed retrospective analysis of all consecutive cardiac arrest survivors treated by MH in our CCU from November 2002 to August 2006. They were classified into two groups, according to whether they met the criteria for cardiogenic shock or not after ROSC and just before MH initiation. Primary outcome measures were inhospital mortality, and the best inhospital and discharge neurological result. Predicted mortality was evaluated by the APACHE II score, and neurological outcome by Cerebral Performance Category score. MH was initiated as soon as Introduction The use of mild hypothermia for comatose survivors of cardiac arrest has been endorsed by the American Heart Association and the International Liaison Committee on Resusci- tation [1,2]. Unintentional overcooling is common with some techniques such as cool intravascular fluid or the use of ice packs. S133 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin P331 P332 Results The induction time for whole body cooling was significantly shorter than that for selective head cooling. The rewarming time for head cooling was significantly shorter than that for whole body cooling. The mean arterial pressure and heart rate were both stable in the head cooling group. The urinary 8-hydroxy- 2-deoxyguanosine concentrations decreased significantly in both groups, but data were significantly lower in the whole body cooling group compared with the selective head cooling group. Five and seven patients, respectively, exhibited good recovery 28 days after admission, in the whole body and selective head cooling groups. Conclusions Mild brain hypothermia therapy suppressed the production of free radicals following global brain ischemia. Whole body cooling had a stronger effect of suppression of free radicals compare with selective head cooling. It is considered that selective head cooling exhibits neuroprotection similar to whole body cooling. Results The induction time for whole body cooling was significantly shorter than that for selective head cooling. The rewarming time for head cooling was significantly shorter than that for whole body cooling. The mean arterial pressure and heart rate were both stable in the head cooling group. The urinary 8-hydroxy- 2-deoxyguanosine concentrations decreased significantly in both groups, but data were significantly lower in the whole body cooling group compared with the selective head cooling group. Five and seven patients, respectively, exhibited good recovery 28 days after admission, in the whole body and selective head cooling groups. Induction of therapeutic mild hypothermia after cardiac arrest: a new combined method to achieve the target temperature H Busch, T Schwab, K Fink, C Bode UKL Freiburg, Germany Critical Care 2007, 11(Suppl 2):P332 (doi: 10.1186/cc5492) H Busch, T Schwab, K Fink, C Bode UKL Freiburg, Germany Critical Care 2007, 11(Suppl 2):P332 (doi: 10.1186/cc5492) Background Clinical and experimental investigations have demon- strated that induction of mild hypothermia works after successful cardiopulmonal resuscitation (CPR) neuroprotection. After the presentation of controlled studies, therapeutic hypothermia moved into the topical international guidelines. Conclusions Mild brain hypothermia therapy suppressed the production of free radicals following global brain ischemia. Whole body cooling had a stronger effect of suppression of free radicals compare with selective head cooling. It is considered that selective head cooling exhibits neuroprotection similar to whole body cooling. Methods and results A total of 50 patients were examined after successful CPR. Twenty-nine patients received 4°C cold infusions after arrival in the heart catheter laboratory. Reduction of magnetic resonance spectroscopy brain temperature by convective head cooling in healthy humans For assessment of regional cooling, voxels lying within the region formed by joining the tips of the lateral ventricles were defined as ‘core’, voxels within approximately one voxel of the brain surface were defined as ‘outer’, and all other voxels were defined as ‘intermediate’. The oesophageal temperature was measured continuously with a fluoroptic thermometer. P331 possible after ROSC and patients were cooled to body temperature 32–34ºC for 12 hours. Reduction of magnetic resonance spectroscopy brain temperature by convective head cooling in healthy humans B Harris1, P Andrews1, I Marshall1, T Robinson2, G Murray1 1University of Edinburgh, UK; 2KCI, Ferndown, UK Critical Care 2007, 11(Suppl 2):P331 (doi: 10.1186/cc5491) P334 21 patients who had received a volume substitute by means of drips from ambient temperature served as a control group. After admission to the ICU, both groups were immediately connected to an external cooling device (CoolGard® or Thermo Wrap®) and were cooled to a target temperature of 33°C (bladder temperature). P332 Retrospective data of S134 Available online http://ccforum.com/supplements/11/S2 Buspirone and dexmedetomidine synergistically reduce the shivering threshold in humans R Lenhardt, R Komatsu, M Orhan-Sungur University of Louisville, KY, USA Critical Care 2007, 11(Suppl 2):P334 (doi: 10.1186/cc5494) Results The average temperature at admission did not differ in both groups (35.5 ± 0.9°C vs 35.89 ± 0.8°C). In the group with initial cooling by means of 4°C cold infusions, a significant temperature decrease could be reached during the invasive coronary diagnostics to admission to the ICU of an average 0.84°C (35.88 ± 0.9°C vs 35.04 ± 0.9°C, P < 0.0001). The middle chill duration up to the achievement of the target temperature after admission was significantly shorter with the combined method (341 ± 113 min versus 553 ± 342 min, P < 0.01). The period to the achievement of the target temperature after the beginning of the external cooling device with the group of the combined method was significantly shorter (163 ± 91 min versus 342 ± 258 min, P < 0.01). Introduction Hypothermia may be therapeutically beneficial in stroke victims; however, it provokes vigorous shivering. Buspirone, a partial serotonin 1A antagonist, and dexmedetomidine, an α2 agonist, linearly reduce the shivering threshold (triggering core temperature) with minimal sedation and respiratory depression. We tested the hypothesis that buspirone and dexmedetomidine synergistically reduce the shivering threshold without producing substantial sedation or respiratory depression. Methods We studied four healthy male volunteers (18–40) on 4 days: (1) control (no drug); (2) buspirone only (60 mg orally); (3) dexmedetomidine only (target plasma concentration 0.6 ng/ml); and (4) combined buspirone and dexmedetomidine in the same doses. Lactated Ringer’s solution (3°C) was infused via a central venous catheter to decrease tympanic membrane temperature by ≈2.2°C/hour; the mean skin temperature was maintained at 31°C. An increase in oxygen consumption more than 25% of baseline identified the shivering threshold. Sedation was evaluated using the Observer’s Assessment Sedation/Alertness scale. Two-way repeated-measures analysis of variance was used to identify interactions between drugs. Data are presented as means ± SDs; P < 0.05 was statistically significant. Conclusions The combined method with initial cooling with 4°C cold solutions shows a sure and actual prestationary cooling procedure to the introduction or realisation of mild hypothermia and offers the possibility to reach the purpose temperature significantly faster. Preclinical introduction of mild hypothermia by means of 4°C cold solutions could be a beneficial criteria in the future treatment, and probably affects the outcome of these patients. P333 A comparison of complications during therapeutic hypothermia between surface cooling and endovascular cooling techniques P Hayden, A Salam, R Beale, M Gillies Guy’s & St Thomas’ NHS Foundation Trust, London, UK Critical Care 2007, 11(Suppl 2):P333 (doi: 10.1186/cc5493) A comparison of complications during therapeutic hypothermia between surface cooling and endovascular cooling techniques A comparison of complications during therapeutic hypothermia between surface cooling and endovascular cooling techniques Results The shivering thresholds were 36.4 ± 0.5°C on the control day; 34.9 ± 0.6°C (P < 0.01 from control) on the buspirone only day; 36.1 ± 0.6°C (P < 0.01 from control) on the dexmedeto- midine only day; and 34.2 ± 0.5°C (P < 0.01 from control) on the combined buspirone and dexmedetomidine day. The calculated mean difference between the thresholds on the combined and the control days was 1.9 ± 0.4°C, while the measured mean difference derived from the difference between the combined and control days was 2.3 ± 0.4°C. There was only trivial sedation with either drug alone or in combination. The respiratory rate and end-tidal PCO2 were well preserved on all days. P Hayden, A Salam, R Beale, M Gillies Guy’s & St Thomas’ NHS Foundation Trust, London, UK Critical Care 2007, 11(Suppl 2):P333 (doi: 10.1186/cc5493) Introduction Therapeutic hypothermia (TH) following cardiac arrest is associated with several complications including sympto- matic bradycardia, coagulopathy, and pneumonia [1]. Furthermore, hyperthermia is associated with poor outcome following brain injury. The incidence of these complications may be increased by excessive temperature fluctuations. We sought to compare complications between two techniques used to induce TH; surface cooling (SC) using ice packs, and endovascular cooling (EV), using the Coolgard™ system (Alsius Corp., USA). Conclusion Buspirone and dexmedetomidine act synergistically to reduce the shivering threshold with only mild sedation and no respiratory depression. This combination might be a valid treatment to prevent shivering in stroke patients during therapeutic hypothermia. Methods A retrospective review was performed of all cardiac arrest patients undergoing TH and surviving ≥48 hours between June 2005 and November 2006. P335 Results Thirty-five patients underwent our TH protocol (SC group = 21, EV group = 14). The incidence of overcooling (<32°C) in the SC group was significantly higher than the EV group (10 vs 1, P = 0.01), whilst a trend towards more episodes of symptomatic bradycardia (SC 9 vs EV 2, P = 0.07) and rebound hyperthermia (SC 9 vs EV 2, P = 0.07) was also present. The incidence of pneumonia (SC 7 vs EV 4, P = 0.77) and coagulopathy/bleeding (SC 2 vs EV 3, P = 0.32) were similar between groups. Bispectral index and suppression ratio are very early predictors of neurological outcome during therapeutic hypothermia after cardiac arrest D Seder, R Riker, G Fraser, H Bruce, T Robbins Maine Medical Center, Portland, ME, USA Critical Care 2007, 11(Suppl 2):P335 (doi: 10.1186/cc5495) Bispectral index and suppression ratio are very early predictors of neurological outcome during therapeutic hypothermia after cardiac arrest , , , Critical Care 2007, 11(Suppl 2):P335 (doi: 10.1186/cc Introduction The bispectral index (BIS) is calculated from fronto- temporal electroencephalogram (EEG), and the suppression ratio (SR) estimates the percentage of EEG suppression. We monitored the BIS and SR during therapeutic hypothermia (TH) and compared them with neurological outcomes of encephalopathic survivors of out-of-hospital cardiac arrest (OHCA). Conclusions (1) SC is associated with a significantly higher incidence of overcooling than EC and may be associated with an increase in complications such as symptomatic bradycardia. (2) SC may also be associated with an increase in rebound hyperthermia. yp Reference y Reference 1. Polderman KH: Application of therapeutic hypothermia in the intensive care unit. Opportunities and pitfalls of a promising treatment modality – Part 2: practical aspects and side effects. Intensive Care Med 2004, 30:757-769. Methods Thirty-two patients with anoxic encephalopathy after OHCA received 18 hours of TH at 32–34°C. BIS monitoring was initiated at the onset of TH, and neuromuscular blockade (NMB) was dosed in response to shivering. Blinded BIS and SR data 1. Polderman KH: Application of therapeutic hypothermia in the intensive care unit. Opportunities and pitfalls of a promising treatment modality – Part 2: practical aspects and side effects. Intensive Care Med 2004, 30:757-769. S135 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin have hypoxic ischaemic encephalopathy (n = 15); adding/ escalating or stopping antiseizure drugs based on the presence/ absence of seizure activity (n = 12); and continuing supportive care in comatose patients diagnosed to have metabolic encephalo- pathy/prolonged sedation effect as the cause for coma (n = 8). Based on these results it can be concluded that, despite limitations such as motion artifacts and influence of sedation on electrical signals, EEG impacts on clinical decision-making processes in critical care. Hence it is beneficial, and more widespread use would improve its diagnostic potential. were recorded after the first dose of NMB, and compared with the Cerebral Performance Category (CPC) at discharge and 6 months. CPC 1 or CPC 2 was considered a good outcome (GO). have hypoxic ischaemic encephalopathy (n = 15); adding/ escalating or stopping antiseizure drugs based on the presence/ absence of seizure activity (n = 12); and continuing supportive care in comatose patients diagnosed to have metabolic encephalo- pathy/prolonged sedation effect as the cause for coma (n = 8). Results Fourteen out of 32 patients (44%) survived, 11 (34%) with GO. Five of the remaining 18 patients died before neuro- logical evaluation at 72 hours, and one patient recovered neurological function but died of cardiogenic shock. No survivor recalled the period of NMB. First NMB was administered a median of 5 hours after cardiac arrest or 87 minutes after initiation of TH, at 35.6 ± 1.7°C. Patients with GO had a higher first post-NMB BIS (39 ± 6 vs 13 ± 14, P < 0.001) and a lower SR (10 ± 12 vs 69 ± 29, P < 0.001) than those with CPC 3–5. yp Reference Initial NMB reduced frontotemporal electromyogram (EMG) power from 52 ± 8 to 27 ± 1 db, P < 0.001. In 17 of the patients with downloaded EEG data, an increase in EMG power of 17 dB (IQR 10–27) from baseline was associated with clinically detectable shivering. Epileptiform discharges were noted on the monitor during NMB in two patients, and seizure activity was confirmed by formal EEG in both. Based on these results it can be concluded that, despite limitations such as motion artifacts and influence of sedation on electrical signals, EEG impacts on clinical decision-making processes in critical care. Hence it is beneficial, and more widespread use would improve its diagnostic potential. References 1. Hirsch LJ, Kull LL:Am J Electroneurodiagnostic Technol 2004, 44:137-158. 2. Newton DEF: Electrophysiological monitoring of general intensive care patients. Intensive Care Med 1999, 25:350- 352. P337 Abstract withdrawn P337 Abstract withdrawn Conclusions In cardiac arrest survivors receiving TH, a higher post-NMB BIS score and a lower SR are very early predictors of neurological outcome. The potential benefits of monitoring BIS and SR, as well as EMG power for early recognition of shivering, and continuous frontotemporal EEG to detect seizures, warrant further study. Aneurysmal subarachnoid hemorrhage induces the expression of Pentraxin3 in patients G Brandi1, E Roncati Zanier1, L Longhi1, G Peri2, G De Simon3, M Tettamanti3, A Mantovani2, N Stocchetti1 1Milan University, Ospedale Maggiore Policlinico IRCCS, Milan, Italy; 2Clinical Institute Humanitas, Milan, Italy; 3Mario Negri Institute, Milan, Italy Critical Care 2007, 11(Suppl 2):P338 (doi: 10.1186/cc5498) Introduction Aneurismal subarachnoid hemorrhage (SAH) is an extremely severe illness associated with a high mortality rate and permanent severe neurological dysfunction in two-thirds of all affected patients. One of the major complications of SAH is vasospasm-associated cerebral ischemia. Clinical and experi- mental data suggest that vasospasm is linked to the inflammatory response associated with SAH. The goal of this study was to investigate the expression of Pentraxin3 (PTX3), a prototypic long pentraxin protein induced by proinflammatory signals in the brain, in SAH patients to test the hypothesis that SAH is followed by an upregulation of PTX3, and establish a temporal relationship between the expression of PTX3 and the induction of vasospasm. We also attempted to establish that PTX3 is detectable in cerebro- spinal fluid (CSF). q Results From the 102 patients (56 men and 48 women) 38 (37.5%) died within the first 30 days, most of them in the first 10 days. Age (OR 13.801, P < 0.04), APACHE II score (OR 1.114, P < 0.008), GCS (OR 2.158, P < 0.002), ICH score (OR 1.183, P < 0.001), FiO2/pO2 (OR 0.996, P < 0.009), haemodynamic instability (OR 2.340, P < 0.002), fever (OR 1.245, P < 0.002), and INR (OR 13.801, P < 0.04) were the strongest associated factors of 30-day mortality. Gender (OR 0.652, P < 0.301), prior illness (OR 1.070, P < 0.870), MODS (OR 0.978, P < 0.803), LOS (OR 0.988, P < 0.266), MV (OR 0.994, P < 0.356) and TT (OR 0.990 P < 0.371) were not associated with mortality. Patients who where operated on had higher mortality but were also more severely ill. Methods We studied eight severe SAH patients admitted to our neuroscience ICU with a median World Federation Neurosurgical Score of 4 and a Fisher score of 4. Arterial, jugular venous blood and CSF samples were routinely obtained every 12 hours for 7 days. PTX3 levels were measured by ELISA in plasma and CSF samples. Conclusion Age, severity of illness, ICH score, hypoxemia, haemodynamic instability, and increased temperature are directly related with the outcome of patients with SICH. Gender, LOS, MV, TT, and MODS did not influence mortality. Maintenance of prehospital medical systems due to clinical advance in acute stroke K Ishii1, Y Wakabayashi1, Y Momii2, T Asano2, H Kenai2, M Yamashita2, M Mori2, Y Hori2, H Nagatomi2 1Oita University School of Medicine, Oita, Japan; 2Nagatomi Neurosurgical Hospital, Oita, Japan Critical Care 2007, 11(Suppl 2):P340 (doi: 10.1186/cc5500) Introduction Recently, the medical treatment in acute stroke has been making rapid progress. Especially, in the ischemic stroke of acute stage, the efficacy of thrombolysis, systemic t-PA or local transarterial urokinase infusion has been proved. However, the effective treatment time is still quite limited. The patients must be brought to the stroke center as soon as possible. We analyzed the reason why most stroke patients delay coming to the stroke center. We extracted the problems and proposed some solutions. Conclusions SAH is characterized by the production of PTX3 and the induction of vasospasm is associated with an upregulation of PTX3 in the CSF that is not detectable in plasma. Reference 1. Muller et al.: Crit Care Med 2001, 29:1404-1407. 1. Muller et al.: Crit Care Med 2001, 29:1404-1407. Patients and methods The clinical subjects consisted of 1,112 consecutive patients with ischemic stroke in the acute stage, hospitalized in our hospital between April 2003 and September 2006. We investigated the clinical course, especially the time from the onset to the physical examination, and radiological exami- nations (CT, MRI, MRA and/or cerebral angiography). The mean age was 72.3 years. Among them, 334 patients were classified as atherothrombosis, 232 were cardiac embolism, 439 were lacunar infarction and 107 were transient ischemic attack. Only 19 patients underwent acute thrombolytic therapy. Aneurysmal subarachnoid hemorrhage induces the expression of Pentraxin3 in patients Results Compared with plasma levels of PTX3 in normal volunteers (<2 ng/ml [1]), SAH induced a marked increase in plasma PTX3 expression. During the first 48 hours following SAH (acute phase), PTX3 arterial and jugular venous levels increased to 36.93 ± 24.32 ng/ml and 33.64 ± 28.76 ng/ml, respectively, and then subsequently decreased concomitantly with the reduction of the inflammation (48–96 hours: subacute phase). PTX3 is detectable in the CSF: mean CSF levels of PTX3 were 4.07 ± 3.64 ng/ml during the acute phase and 0.69 ± 0.44 ng/ml during the subacute phase (t test: P < 0.05 compared with the acute phase). In the presence of vasospasm (four patients), we detected a second peak of PTX3 (4.03 ± 2.85 ng/ml) in CSF samples (t test: P < 0.05 compared with the subacute phase) that was not detectable in plasma. P338 Patients who where operated on had higher mortality but were also more severely ill. M Sartzi, A Papaeveggelou, A Stogiannidi, P Kouki, B Romanou, E Panagiotakopoulou, G Kallitsi, K Mihas, F Tsidemiadou, P Clouva-Molyvda General Hospital of Eleusis, Athens, Greece Critical Care 2007, 11(Suppl 2):P339 (doi: 10.1186/cc5499) P336 Role of bedside electroencephalogram in intensive care: a critical review R Jayaram Ramachandran, C Hargreaves, S Sinha Whittington Hospital NHS Trust, London, UK Critical Care 2007, 11(Suppl 2):P336 (doi: 10.1186/cc5496) Role of bedside electroencephalogram in intensive care: a critical review Role of bedside electroencephalogram in intensive care: a critical review R Jayaram Ramachandran, C Hargreaves, S Sinha Whittington Hospital NHS Trust, London, UK Critical Care 2007, 11(Suppl 2):P336 (doi: 10.1186/cc5496) Electroencephalogram (EEG) is an appropriate monitoring tool in intensive care because it is linked to cerebral metabolism, is sensitive to ischaemia/hypoxia, can detect neuronal dysfunction at a reversible stage and is the best method to detect seizure activity. Scientific data have proved utility of continuous EEG monitoring in intensive care [1,2]. But there is a paucity of data relating to single recordings of EEG especially in general ICUs. A retrospective chart review of patients who had bedside EEG in a medical–surgical ICU was done. Data were collected with a focus on: indication for requesting EEG, technical difficulties during the study, the report and its influence on subsequent clinical manage- ment. Forty-two charts were reviewed. The indications were: evaluation of persistent comatose state (n = 27), to diagnose/exclude seizure activity and nonconvulsive status epilepsy (n = 12), and as an adjunct to support clinical diagnosis of suspected brain death prior to formal testing (n = 3). Movement artifacts led to technical difficulty in four studies. EEG confirmed: moderate to severe nonspecific brain dysfunction as the cause for persistent comatose state by the presence of either diffuse slowing with theta/delta activity, absence of cerebral activity, continuous rhythmic and semi rhythmic lateralized/bilateral epileptiform discharges, burst suppression pattern or continuous bilateral slow U-shaped waves; anoxic brain damage by absence of changes in electrical signals following external application of noxious stimuli; and seizure activity by epileptiform discharges. Twelve reports stated that use of sedation interfered with EEG interpretation. The following clinical decisions were made based on the EEG report in conjunction with clinical findings: initiating withdrawal of life support or ‘do-not-resuscitate orders’ in patients diagnosed to S136 Available online http://ccforum.com/supplements/11/S2 P338 Methods Retrospective analysis of prospectively gathered data of 102 patients with SICH treated in our ICU during the past 8 years. On admission the following data were registered: vascular risk factors (high blood pressure, diabetes mellitus), age, gender, APACHE II score, GCS, hemorrhage characteristics (location, side, volume, mass effect), surgical procedure, MODS, blood pressure (systolic, diastolic, mean), pulse pressure, pulse rate, laboratory parameters (hemoglobin, white cell and platelet count, INR, serum values for Na, glucose, lactate, creatinin, bilirubin). Also registered were length of stay (LOS), duration of mechanical ventilation (MV), time of intubation (TT) and patient outcome. Haemodynamic instability was defined as low mean blood pressure and support with vasoactive and inotrop drugs. Statistical evaluation was performed using univariate and multivariate logistic regression, Student’s t test Pearson’s chi-square test and Fisher’s exact statistic were used. Methods Retrospective analysis of prospectively gathered data of 102 patients with SICH treated in our ICU during the past 8 years. On admission the following data were registered: vascular risk factors (high blood pressure, diabetes mellitus), age, gender, APACHE II score, GCS, hemorrhage characteristics (location, side, volume, mass effect), surgical procedure, MODS, blood pressure (systolic, diastolic, mean), pulse pressure, pulse rate, laboratory parameters (hemoglobin, white cell and platelet count, INR, serum values for Na, glucose, lactate, creatinin, bilirubin). Also registered were length of stay (LOS), duration of mechanical ventilation (MV), time of intubation (TT) and patient outcome. Haemodynamic instability was defined as low mean blood pressure and support with vasoactive and inotrop drugs. Statistical evaluation was performed using univariate and multivariate logistic regression, Student’s t test Pearson’s chi-square test and Fisher’s exact statistic were used. Results From the 102 patients (56 men and 48 women) 38 (37.5%) died within the first 30 days, most of them in the first 10 days. Age (OR 13.801, P < 0.04), APACHE II score (OR 1.114, P < 0.008), GCS (OR 2.158, P < 0.002), ICH score (OR 1.183, P < 0.001), FiO2/pO2 (OR 0.996, P < 0.009), haemodynamic instability (OR 2.340, P < 0.002), fever (OR 1.245, P < 0.002), and INR (OR 13.801, P < 0.04) were the strongest associated factors of 30-day mortality. Gender (OR 0.652, P < 0.301), prior illness (OR 1.070, P < 0.870), MODS (OR 0.978, P < 0.803), LOS (OR 0.988, P < 0.266), MV (OR 0.994, P < 0.356) and TT (OR 0.990 P < 0.371) were not associated with mortality. P340 Maintenance of prehospital medical systems due to clinical advance in acute stroke General Hospital of Eleusis, Athens, Greece Introduction We evaluated the factors that may influence the outcome of patients with spontaneous intracerebral hemorrhage (SICH). Critical Care 2007, 11(Suppl 2):P339 (doi: 10.118 P341 Effects of intraaortic balloon counterpulsation on middle cerebral artery blood flow velocities A Vakalos, D Setzis, P Doukelis, S Pampori, D Matamis Papageorgiou General Hospital, Thessaloniki, Greece Critical Care 2007, 11(Suppl 2):P341 (doi: 10.1186/cc5501) Gram-negative bacteremia is an independent predisposing factor for critical illness polyneuromyopathy Gram-negative bacteremia is an independent predisposing factor for critical illness polyneuromyopathy K Kritikos, E Angelopoulos, A Siafaka, M Kontogeorgi, S Tsikriki, D Kanaloupiti, M Pratikaki, M Poriazi, V Gerovasili, C Routsi, C Roussos, S Nanas Medical School, National and Kapodistrian University, Evangelismos Hospital, Athens, Greece Critical Care 2007, 11(Suppl 2):P343 (doi: 10.1186/cc5503) Table 1 (abstract P341) WS vs 1:1 WS vs 1:2 WS vs 1:3 Vmax P > 0.05 P < 0.01 P < 0.01 Vmean P > 0.05 P < 0.001 P < 0.001 Introduction Critical illness polyneuromyopathy (CIPM) is a major clinical problem in the ICU resulting in prolonged ICU stay and increased morbidity and mortality. Conclusions Left ventricular support with IABP significantly changed the flow velocity pattern of our patients. The pump significantly increased the Vmax and the Vmean at the 1:2 and 1:3 settings because of pump inflation during the diastole. We suggest that the velocities did not change at the 1:1 setting because the end-diastolic flow velocities reduce during every pulse, according to pump deflation. Objective To investigate risk factors of CIPM involved, in a general multidisciplinary ICU. Patients and participants Four hundred and seventy-four (323 males/151 females, age 55 ± 19) consecutively admitted patients in a 28-bed university multidisciplinary ICU were prospectively evaluated. All patients were assigned admission APACHE II (15 ± 7) and SOFA (6 ± 3) scores and were subsequently evaluated for newly developed neuromuscular weakness. We examined muscle strength according to the Medical Research Council scale, deep tendon reflexes, sensory function and muscle wasting. Laboratory values and medical therapy were recorded daily. Other potential causes of new-onset generalized weakness after ICU admission were excluded before the diagnosis of CIPM was established. Out of the 474 patients, 185 remained in the ICU for ≥10 days. Effects of intraaortic balloon counterpulsation on middle cerebral artery blood flow velocities Results In 1,421 ICU patients who were evaluated in 24 studies, 655 (46%) were diagnosed with CINMA. All enrolled patients were receiving protracted mechanical ventilation, had sepsis, or had multiple organ failure. Diagnostic criteria for CINMA were hetero- geneous and few reports explicitly differentiated between the polyneuropathic, myopathic and mixed types of CINMA. CINMA was linked in several studies to hyperglycemia, the systemic inflam- matory response syndrome, sepsis, renal replacement therapy, and catecholamine administration. In contrast, across studies there was no consistent relationship between CINMA and patient age, gender, severity of illness, multiple organ failure, and use of gluco- corticoids, neuromuscular blockers, aminoglycosides, or midazolam. Mortality was not increased in patients with CINMA, but mechanical ventilation and ICU and hospital stays were prolonged. Conclusions The risk of CINMA is nearly 50% in a subset of ICU patients with sepsis, multiorgan failure, or protracted mechanical ventilation, but there were no data to support CINMA as an independent predictor of death. The impact of frequently cited risk factors is uncertain, but emerging data indicate glycemic control decreases CINMA risk in vulnerable patients. A Vakalos, D Setzis, P Doukelis, S Pampori, D Matamis Papageorgiou General Hospital, Thessaloniki, Greece Critical Care 2007, 11(Suppl 2):P341 (doi: 10.1186/cc5501) Introduction The intraaortic balloon pump has been shown to improve cardiac output and diastolic coronary flow. The aim of our study was to determine the effects of intraaortic counterpulsation (IABP) on cerebral blood flow velocities measured on the middle cerebral artery. Methods In 11 cardiac surgery patients receiving IABP postoperatively, blood flow velocities in the middle cerebral artery were assessed by transcranial Doppler (TCD). In each patient, measurements of Vmax, Vmean and Vmin were performed at four different pump settings: without support (WS), and at pump assist pulse with ratio 1:1, 1:2 and 1:3. p Results Repeated-measures analysis of variance: P = 0.0006, considered extremely significant variation of TCD measurements among IABP settings. Comparing all pairs of Vmax, Vmean and Vmin values, we found that Vmax and especially Vmean are significantly greater at the 1:2 and 1:3 pump settings, but not at the 1:1 setting. We also found that the end diastolic velocities (Vmin) were significant lower during the pump deflation. None of our patients had a significant diastolic flow velocity reversal during the pump deflation. Outcome of intensive care unit patients with spontaneous intracerebral hemorrhage P342 Neuromuscular dysfunction acquired during a systematic review R Stevens, D Dowdy, R Michaels, P Mendez-Te P Pronovost, D Needham Johns Hopkins University School of Medicine, Ba Critical Care 2007, 11(Suppl 2):P342 (doi: 10.11 Background Patients with critical illness can ac of weakness and dependence on mechanical v the delayed admission is through another hospital, not a stroke center. The patients denied their symptoms are not so rare. The patients or their family often hesitate to request the emergency car. Conclusions The most significance point for rapid diagnosis and therapy is that people must doubt ‘stroke’ at first. We should further educate citizens to the warning signs of stroke and also the necessity of emergency admission using an emergency car. In addition, we should justly build a core stroke center in the district and centralize the patients. the delayed admission is through another hospital, not a stroke center. The patients denied their symptoms are not so rare. The patients or their family often hesitate to request the emergency car. the delayed admission is through another hospital, not a stroke center. The patients denied their symptoms are not so rare. The patients or their family often hesitate to request the emergency car. been linked to peripheral nerve and muscle injury. Our aim was to systematically review published data on the diagnosis, risk factors and outcomes of patients with critical illness neuromuscular abnormalities (CINMA). Conclusions The most significance point for rapid diagnosis and therapy is that people must doubt ‘stroke’ at first. We should further educate citizens to the warning signs of stroke and also the necessity of emergency admission using an emergency car. In addition, we should justly build a core stroke center in the district and centralize the patients. Methods MEDLINE, EMBASE, CINAHL, and the Cochrane Library were searched, and studies were included if they reported on ICU patients > 16 years old who were evaluated for CINMA clinically and electrophysiologically, and they contained sufficient data to quantitatively measure the association between CINMA and clinically relevant exposures and/or outcomes. Two reviewers independently extracted data on study methodology and quality, methods for diagnosing CINMA, and CINMA prevalence, risk factors, and outcomes. Outcome of intensive care unit patients with spontaneous intracerebral hemorrhage Outcome of intensive care unit patients with spontaneous intracerebral hemorrhage Results Two hundred and forty-one patients (21.7%) were hospitalized within 3 hours from the onset, and 365 patients (32.9%) were within 6 hours. Among them, only 438 were admitted by ambulance. We found the following results. The main reason for Introduction We evaluated the factors that may influence the outcome of patients with spontaneous intracerebral hemorrhage (SICH). S137 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin the delayed admission is through another hosp center. The patients denied their symptoms are patients or their family often hesitate to request the Conclusions The most significance point for ra therapy is that people must doubt ‘stroke’ at further educate citizens to the warning signs of s necessity of emergency admission using an e addition, we should justly build a core stroke ce and centralize the patients. P341 Effects of intraaortic balloon counterpulsati cerebral artery blood flow velocities A Vakalos, D Setzis, P Doukelis, S Pampori, D Papageorgiou General Hospital, Thessaloniki, Gre Critical Care 2007, 11(Suppl 2):P341 (doi: 10.11 Introduction The intraaortic balloon pump has improve cardiac output and diastolic coronary flo study was to determine the effects of intraaortic (IABP) on cerebral blood flow velocities measu cerebral artery. Methods In 11 cardiac surgery patients postoperatively, blood flow velocities in the midd were assessed by transcranial Doppler (TCD) measurements of Vmax, Vmean and Vmin were p different pump settings: without support (WS), a pulse with ratio 1:1, 1:2 and 1:3. Results Repeated-measures analysis of varian considered extremely significant variation of TC among IABP settings. Comparing all pairs of Vm values, we found that Vmax and especially Vmea greater at the 1:2 and 1:3 pump settings, but not We also found that the end diastolic veloc significant lower during the pump deflation. No had a significant diastolic flow velocity reversal deflation. Table 1 (abstract P341) WS vs 1:1 WS vs 1:2 Vmax P > 0.05 P < 0.01 Vmean P > 0.05 P < 0.001 Conclusions Left ventricular support with I changed the flow velocity pattern of our pa significantly increased the Vmax and the Vmean a settings because of pump inflation during the dia that the velocities did not change at the 1:1 se end-diastolic flow velocities reduce during every to pump deflation. P344 Introduction The objective was to determine the relationship of early hypothermia to multiple organ failure and mortality in severely injured trauma patients. Interhospital cooperation after critical and emergency care for patients with cervical–thoracic–abdominal trauma and emergency diseases in the local medical area in a typical urban city of Japan Methods This prospective observational study was performed at seven Level I trauma centers over 16 months. Severely injured patients with hypoperfusion and a need for blood transfusion during the early hospital course were followed with near-infrared spectroscopy-derived tissue oxygen saturation (StO2) and clinical variables. Outcomes including multiple organ dysfunction syn- drome (MODS) and 28-day mortality were evaluated. Hypothermia was defined as temperature < 35°C within the first 6 hours. Y Moriwaki, M Sugiyama, S Arata, N Harunari, H Manaka, T Katsumura, T Yamada, N Suzuki Yokohama City University Medical Center, Yokohama, Japan Critical Care 2007, 11(Suppl 2):P344 (doi: 10.1186/cc5504) Background Capacity of the critical care and emergency center (CCEC) is usually restricted. Transfer of patients from CCEC is one of the most important issues in the CCEC. p Results Hypothermia was common (43%, 155/359). Hypothermic patients were more likely than normothermic patients to develop MODS (21% vs 9%, P = 0.003), but did not have increased mortality rates (16% vs 12%, P = 0.28). The maximum base deficit (Max BD) in hypothermic patients did not discriminate between those who did or did not develop MODS (9.8 ± 4.6 mEq/l vs 9.4 ± 4.4 mEq/l, P = 0.56) but had good discrimination for mortality in both hypothermic and normothermic patients. Significant predictors of MODS using multivariate analysis included minimum StO2 (P = 0.0002) and hypothermia (P = 0.01), but not Max BD (P = 0.09). Predictors for mortality with multivariate analysis included minimum StO2 (P = 0.0004) and Max BD (P = 0.01), but not hypothermia (P = 0.74). Hypothermia remained a significant risk factor for MODS when fluid/blood infusion volumes were included in the multivariate model. Subjects and methods We examined interhospital cooperation after critical and emergency care for life-threatening cervical– thoracic–abdominal trauma (n = 501) and thoracoabdominal emergency diseases (n = 236) who were treated with intensive care in our CCEC and were able to be discharged or transferred to another acute treatment hospital. P345 CIPM had a higher admission APACHE II score (18.9 ± 6.6 vs 15.6 ± 6.4, P = 0.004) and SOFA score (8.4 ± 2.9 vs 7.1 ± 2.9, P = 0.013). Multivariate logistic regression analysis showed that risk factors independently associated with the development of CIPM were severity of illness at the time of admission to the ICU, administration of aminoglycoside antibiotics and high blood glucose levels. Analysis according to severity of illness stratifica- tion revealed the emergence of Gram-negative bacteremia as the most important independent predisposing factor for CIPM development in less severely ill patients. Early hypothermia in severely injured trauma patients is a significant risk factor for multiple organ dysfunction syndrome but not mortality G Beilman1, T Nelson2, A Nathens3, F Moore4, P Rhee5, J Puyana6, E Moore7, S Cohn8 1University of Minnesota, Minneapolis, MN, USA; 2Princeton Reimbursement Group, Minneapolis, MN, USA; 3St Michaels Hospital, Toronto, Canada; 4University of Texas–Houston, Houston, TX, USA; 5University of Southern California, San Diego, CA, USA; 6University of Pittsburgh, PA, USA; 7University of Colorado, Denver, CO, USA; 8University of Texas, San Antonio, TX, USA Critical Care 2007 11(Suppl 2):P345 (doi: 10 1186/cc5505) Conclusions CIPM has a high incidence in the ICU setting. Our study revealed the important association that Gram-negative bacteremia, aminoglycosides, hyperglycemia and severity of illness have with CIPM development. al Care 2007, 11(Suppl 2):P345 (doi: 10.1186/cc5505) P342 Neuromuscular dysfunction acquired during critical illness: a systematic review R Stevens, D Dowdy, R Michaels, P Mendez-Tellez, P Pronovost, D Needham Johns Hopkins University School of Medicine, Baltimore, MD, USA Critical Care 2007, 11(Suppl 2):P342 (doi: 10.1186/cc5502) Background Patients with critical illness can acquire a syndrome of weakness and dependence on mechanical ventilation that has Results Forty-four (23.8%) out of those 185 patients developed generalized weakness that met the criteria for CIPM. Patients with S138 Available online http://ccforum.com/supplements/11/S2 P344 Results Of the trauma patients directly transferred to our center, 48% were transferred to the ‘affiliated hospitals’, whose medical staffs were dispatched from the ‘departments’ in our university, 17% were transferred to the nonaffiliated hospitals, and 34% were directly discharged from our center. Of emergency disease patients, 28% were transferred to the affiliated hospitals, 20% were transferred to other hospitals, and 52% were directly discharged. Patients staying in our center for more than 14 days tended to be transferred to the affiliated hospital. Of trauma patients indirectly transferred from other hospital to our center, 30% and 11% were transferred to the affiliated and nonaffiliated hospitals, and 19% were directly discharged. Of emergency disease patients, these values were 21%, 7%, and 13%, respectively. Patients staying in our center for more than 14 days tended to be transferred to the affiliated hospital. Conclusions Hypothermia is common in severely injured trauma patients and is a risk factor for MODS but not mortality. Minimum StO2 predicts MODS and mortality in normothermic and hypothermic patients, while the predictive effect of BD for MODS is blunted in the presence of hypothermia. The nonlactate gap: a novel predictor of organ failure and mortality following major trauma The nonlactate gap: a novel predictor of organ failure and mortality following major trauma Discussion and conclusion These results are thought to be a common situation in a typical urban city in the world. Now, the interhospital cooperation between city hospital and referral hospital does not function well because of poor understanding of re- transfer to the previous hospital, resulting in dysfunction of the management of critical patients in the local medical area. It is important to construct a new interhospital-cooperation system based on the local medical area. S Robertson1, E Dickson2, G Richards1 1Johannesburg Hospital, Johannesburg, South Africa; 2Royal Glasgow Infirmary, Glasgow, UK Critical Care 2007, 11(Suppl 2):P346 (doi: 10.1186/cc5506) y g y, g , Critical Care 2007, 11(Suppl 2):P346 (doi: 10.1186/cc Introduction Early identification of patients who are not fully resuscitated following major trauma improves outcome. However, current markers of clinically occult hypoperfusion, such as lactate and base deficit, have serious limitations, and our aim was to establish a new endpoint of resuscitation. Methods In a prospective study conducted in a Level 1 trauma unit, 49 consecutive patients admitted to the trauma ICU were evaluated. Serum electrolytes, albumin, phosphate and lactate S139 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Conclusion The combination of prehospital and emergency department systolic blood pressure is a simple yet extremely powerful predictor of mortality following major trauma and should be used as a triage tool to rapidly identify the highest risk patients. were measured on admission. We derived the calculated ion gap using a simplified Stewart–Figge equation, and subtracted the measured serum lactate from the calculated ion gap to obtain the nonlactate gap (NLG). Results See Table 1. The NLG discriminated survivors from non- survivors (P = 0.008, analysis of variance). An NLG above 2 mmol/l was associated with an increased risk of mortality (P = 0.010, Fisher’s exact test). No patient with an NLG less than 2 mmol/l died; 32.4% of the patients with an NLG above 2 mmol/l died. A NLG above 2 mmol/l also correlated strongly with organ failure (Multiple Organ Dysfunction Syndrome score P = 0.011, Sequen- tial Organ Failure Assessment score P = 0.011, Mann–Whitney U test). E Charalambous1, S Manousakis1, A Kapasaki1, C Chronaki2, G Vrouchos1 1Venizelio General Hospital of Heraklion, Greece; 2ICS-FORTH, Heraklion, Greece Critical Care 2007, 11(Suppl 2):P348 (doi: 10.1186/cc5508) Table 1 (abstract P346) Survived Died Total NLG < 2 mmol/l 15 (39.5%) 0 (0%) 15 (30.6%) NLG > 2 mmol/l 23 (60.5%) 11 (100%) 34 (69.4%) Total 38 (100%) 11 (100%) 49 (100%) Introduction Blunt chest trauma is often accompanied by traumatic cardiac injury (TCI), formerly called cardiac contusion. Severe TCI can affect the prognosis of chest trauma patients due to cardiac arrhythmias, heart failure, or cardiac tamponade. The objective of this study was the detection and evaluation of TCI in chest trauma. Introduction Blunt chest trauma is often accompanied by traumatic cardiac injury (TCI), formerly called cardiac contusion. Severe TCI can affect the prognosis of chest trauma patients due to cardiac arrhythmias, heart failure, or cardiac tamponade. The objective of this study was the detection and evaluation of TCI in chest trauma. Methods Twenty-seven consecutive patients without cardiac disease history (five females), mean age 37.2 years (63% <35 years) were admitted to the ICU with blunt chest trauma. Five patients had minor head brain injury. The majority needed mechanical ventilation support. The mean Injury Severity Score (ISS) was 21.1 (11–34). The following injuries/lesions of thorax or lung parenchyma were identified on chest and abdominal CT scan: fractures of clavicle, sternum, ribs, scapula or vertebral column, lung contusion, hemo/pneumothorax, hemo/pneumomediastinum, abdominal organ injury. TCI diagnosis was based on auscultation findings (pericardial friction rub, new cardiac murmurs), electrocardiogram (ECG) findings (ST–T disturbances, arrhythmias), cardiac enzymes (CE) (cardiac Tropinin I, CK-MB), transthoracic echocardiography (TTE) (wall motion abnormalities (WMA), reduced left ventricular ejection fraction (LVEF) pericardial effusion (PE)), and thorax CT findings. Results Twenty-two out of 27 patients (81%) exhibited at least one sign of TCI, 17/27 (63%) had more than two signs: ECG changes (18/22, 81.8%), mostly ST–T disturbances of left precordial or inferior leads, slight CE increase (17/22, 72%), PE in TTE or CT (12/22, 54,5%), WMA, mostly of the interventricular septum wall (6/22, 27%), reduced LVEF (5/22, 23%), or pericardial friction rub (5/22, 23%). Patients with TCI signs had more frequently bilateral or right-sided hemothorax (16/22, 72%), bilateral lung contusion (15/22, 68%), right-sided rib fracture (15/22, 68%), abdominal organ injury (spleen, left kidney/adrenal, liver) (14/22, 63%) or right-sided pneumothorax (13/22, 59%). Two patients (one with flail chest) exhibited PE leading to cardiac tamponade. Pericardiocentesis was performed with success. None of the patients had severe ventricular arrhythmia. Five young patients had mildly reduced LVEF, in almost all cases transient. E Charalambous1, S Manousakis1, A Kapasaki1, C Chronaki2, G Vrouchos1 1Venizelio General Hospital of Heraklion, Greece; 2ICS-FORTH, Heraklion, Greece Critical Care 2007, 11(Suppl 2):P348 (doi: 10.1186/cc5508) There was a positive correlation between ISS and TCI severity. C l i TCI i f i bl h Addi i l cardiac injury (TCI), formerly called cardiac contusion. Severe TCI can affect the prognosis of chest trauma patients due to cardiac arrhythmias, heart failure, or cardiac tamponade. The objective of this study was the detection and evaluation of TCI in chest trauma. Methods Twenty-seven consecutive patients without cardiac disease history (five females), mean age 37.2 years (63% <35 years) were admitted to the ICU with blunt chest trauma. Five patients had minor head brain injury. The majority needed mechanical ventilation support. The mean Injury Severity Score (ISS) was 21.1 (11–34). The following injuries/lesions of thorax or lung parenchyma were identified on chest and abdominal CT scan: fractures of clavicle, sternum, ribs, scapula or vertebral column, lung contusion, hemo/pneumothorax, hemo/pneumomediastinum, abdominal organ injury. TCI diagnosis was based on auscultation findings (pericardial friction rub, new cardiac murmurs), electrocardiogram (ECG) findings (ST–T disturbances, arrhythmias), cardiac enzymes (CE) (cardiac Tropinin I, CK-MB), transthoracic echocardiography (TTE) (wall motion abnormalities (WMA), reduced left ventricular ejection fraction (LVEF) pericardial effusion (PE)), and thorax CT findings. Conclusions We describe the NLG for the first time, and quantify it using simple bedside calculations derived from routine blood investigations. The NLG is an excellent marker for organ failure and death following major injury, and should be used to guide trauma resuscitation. Traumatic cardiac injury in chest trauma E Charalambous1, S Manousakis1, A Kapasaki1, C Chronaki2, G Vrouchos1 1Venizelio General Hospital of Heraklion, Greece; 2ICS-FORTH, Heraklion, Greece Critical Care 2007, 11(Suppl 2):P348 (doi: 10.1186/cc5508) P347 Prehospital hypotension that persists on arrival at the emergency department is a powerful predictor of mortality following major trauma E Dickson, S Robertson, D Van Niekerk, J Goosen, F Plani, K Boffard Johannesburg Hospital Trauma Unit and University of the Witwatersrand, Johannesburg, South Africa Critical Care 2007, 11(Suppl 2):P347 (doi: 10.1186/cc5507) Results Twenty-two out of 27 patients (81%) exhibited at least one sign of TCI, 17/27 (63%) had more than two signs: ECG changes (18/22, 81.8%), mostly ST–T disturbances of left precordial or inferior leads, slight CE increase (17/22, 72%), PE in TTE or CT (12/22, 54,5%), WMA, mostly of the interventricular septum wall (6/22, 27%), reduced LVEF (5/22, 23%), or pericardial friction rub (5/22, 23%). Patients with TCI signs had more frequently bilateral or right-sided hemothorax (16/22, 72%), bilateral lung contusion (15/22, 68%), right-sided rib fracture (15/22, 68%), abdominal organ injury (spleen, left kidney/adrenal, liver) (14/22, 63%) or right-sided pneumothorax (13/22, 59%). Two patients (one with flail chest) exhibited PE leading to cardiac tamponade. Pericardiocentesis was performed with success. None of the patients had severe ventricular arrhythmia. Five young patients had mildly reduced LVEF, in almost all cases transient. There was a positive correlation between ISS and TCI severity. Objective Outcome following major injury is time dependent. Early identification of high-risk patients allows rapid decision-making and correction of life-threatening disorders. Complex scoring systems are of limited value during major trauma resuscitation. Our aim was to evaluate the utility of a single blood pressure during the prehospital phase in combination with the blood pressure on arrival at the emergency department. Methods Data were collected prospectively on 1,111 patients admitted to a Level 1 South African trauma unit over a 1-year period. Patients were subdivided into two groups according to the combination of their prehospital (PH) and emergency department (ED) blood pressure. Hypotension was defined as a systolic blood pressure less than 90 mmHg. Mortality was defined as death within 30 days. Conclusions TCI is frequent in blunt chest trauma. Additional ECG findings and an increase in CE suggest possible TCI to be confirmed by a bedside TTE study. TCI usually accompanies bilateral hemothorax, lung contusion, or right-sided rib fracture. Results The mortality in patients (n = 1,031) with normal PH and ED blood pressure was 5.4%. The mortality in patients (n = 80) with PH and ED hypotension was significantly higher at 45% (P < 0.0001, chi-square test) (Table 1). P349 P350 Full-body low-dosage X-ray instead of single X-ray serie in trauma: a preliminary experience report of a modified advanced trauma life support algorithm A Exadaktylos, H Brunner, L Martinolli, L Benneker, F Gatter R Soyka, H Bonel, H Zimmermann Inselspital Bern, Switzerland Critical Care 2007, 11(Suppl 2):P350 (doi: 10.1186/cc5510) Introduction Patients presenting with trauma normally req resuscitation according to the advanced trauma life support (AT algorithm. Techniques suggested during primary survey include ray of C-spine, chest and pelvis. This can be time consuming a radiation intensive. In comparison with conventional mult radiographs, Lodox (Statscan), a full-body digital radiology dev performs a.p. and lateral whole-body examinations in 3–5 minu with about one-third of the irradiation and without the necessity lifting patients. This is the first device installed in Europe. Methods This paper describes our experience with the use o implementing LODOX (median time 27 min to 24 min). In 54/94 patients an additional full body CT scan was performed as adjunct to secondary survey. In only 14/54 patients were additional conventional X-rays necessary to visualize the skeleton. Conclusion The implementation of a modified ATLS algorithm using LODOX allows a complete a.p. and lateral whole-body examination without a significant increase in the time taken for resuscitation. Since we are at the very beginning of a learning curve we are confident that in future the time for the ATLS primary survey can be markedly reduced. The LS imaging system seems to be a useful tool for rapid screening and management of trauma patients. implementing LODOX (median time 27 min to 24 min). In 54/94 patients an additional full body CT scan was performed as adjunct to secondary survey. In only 14/54 patients were additional conventional X-rays necessary to visualize the skeleton. extravasation site computed tomography (CT). In this study we investigated the site and extent of contrast medium extravasation on CT findings and its effect on treatment and predicting clinical outcome in trauma patients. Conclusion The implementation of a modified ATLS algorithm using LODOX allows a complete a.p. and lateral whole-body examination without a significant increase in the time taken for resuscitation. Since we are at the very beginning of a learning curve we are confident that in future the time for the ATLS primary survey can be markedly reduced. The LS imaging system seems to be a useful tool for rapid screening and management of trauma patients. P351 Results The incidence of extravasation site was intraperitoneal in 33 cases (66%), retroperitoneal in 13 cases (26%), and intrapelvic in four cases (8%). The frequency of injured vessels showing extravasation was 18 (36%) hepatic vessels, nine (18%) splenic vessels and six (12%) iliac vessels. There was no correlation between the extravasation site and ICU or total hospitalization duration (P > 0.523). Sixteen patients with intraperitoneal extravasation required surgical intervention, six patients underwent angiography with embolization. In patients with retroperitoneal extravasation, nine were treated conservatively and two with embolization. Over all there were no significant differences between the extravasation site and treatment modality. The intraperitoneal group had the highest mortality with 13 deaths (11/33, 39%) and the highest early mortality rate (10/13, 76%) in the first 24 hours (P = 0.001). Peripheral oxygen extraction predicts organ failure and mortality following major trauma Peripheral oxygen extraction predicts organ failure and mortality following major trauma S Robertson1, E Dickson2, G Richards1 1Johannesburg Hospital, Johannesburg, South Africa; 2Royal Glasgow Infirmary, Glasgow, UK Critical Care 2007, 11(Suppl 2):P351 (doi: 10.1186/cc5511) ritical Care 2007, 11(Suppl 2):P351 (doi: 10.1186/cc55 Introduction Current markers of occult hypoperfusion following major trauma have serious limitations. Our aim was to evaluate oxygen extraction as a resuscitation endpoint, and predictor of organ failure and mortality following trauma. Methods A prospective, noninterventional study of 39 consecutive patients admitted to a Level 1 trauma unit ICU. Blood gas analysis was performed on samples from three locations: central venous line, peripheral venous line, and arterial line. Blood was drawn 6- hourly in the first 24 hours, and oxygen extraction calculated using the Fick equation. Organ failure was assessed using MODS and SOFA scores. Conclusion CT findings in patients with blunt abdominal trauma showed no significant correlation between the contrast medium extravasation site and treatment modality, ICU hospitalization duration, or final results. However, patients with intraperitoneal extravasation required more aggressive transfusion with packed red cells and had a higher mortality rate in the first 24 hours. Results See Table 1. Peripheral, but not central, oxygen extraction with a threshold of 150 ml oxygen extracted per litre of blood distinguished survivors from nonsurvivors on admission to the trauma ICU. Low peripheral oxygen extraction (<150 ml) had an odds ratio for risk of death of 5.3 (P = 0.016, Fisher’s exact test) and was associated with higher organ failure scores (P = 0.044, Mann– Whitney U test). A trend of increasing peripheral oxygen extraction was also a strong predictor of mortality (P = 0.019, Mann–Whitney U test) and organ failure (P = 0.003, Mann–Whitney U test). P350 Full-body low-dosage X-ray instead of single X-ray series in trauma: a preliminary experience report of a modified advanced trauma life support algorithm A Exadaktylos, H Brunner, L Martinolli, L Benneker, F Gatterer, R Soyka, H Bonel, H Zimmermann Inselspital Bern, Switzerland Critical Care 2007, 11(Suppl 2):P350 (doi: 10.1186/cc5510) Table 1 (abstract P351) Survived Died Total Extract < 150 ml 8 6 14 Extract > 150 ml 23 2 25 Total 31 8 39 Introduction Patients presenting with trauma normally require resuscitation according to the advanced trauma life support (ATLS) algorithm. Techniques suggested during primary survey include X- ray of C-spine, chest and pelvis. This can be time consuming and radiation intensive. In comparison with conventional multiple radiographs, Lodox (Statscan), a full-body digital radiology device, performs a.p. and lateral whole-body examinations in 3–5 minutes with about one-third of the irradiation and without the necessity for lifting patients. This is the first device installed in Europe. Conclusions With an arterial and venous blood sample, and a simple equation, we have for the first time demonstrated that absolute and serial peripheral oxygen extraction are powerful predictors of organ failure and mortality following major injury. Methods This paper describes our experience with the use of a new low-dose X-ray technique as part of our modified ATLS algorithm, where single–total a.p./lateral body radiographs have been implemented as adjuncts to primary survey in favour of several conventional X-rays. P349 Methods Fifty patients admitted to our emergency department with blunt abdominal trauma showing contrast medium extravasa- tion on abdominal–pelvic CT scan were included in our study for 33 months. Patients were prospectively collected and medical records were reviewed and analyzed retrospectively. The patients’ clinical and laboratory findings, abdominal sonographic (FAST) findings, and CT findings were reviewed. Extravasation sites were classified as intraperitoneal, retroperitoneal, intrapelvic and correlated with post-treatment complications, mortality and morbidity rates. P349 Prognosis of blunt abdominal trauma patients with contrast medium extravasation on computed tomography scan K Lee, H Shin Wonju Medical College, Wonju, Republic of Korea Critical Care 2007, 11(Suppl 2):P349 (doi: 10.1186/cc5509) Table 1 (abstract P347) SBP < 90 mmHg SBP > 90 mmHg Alive 55.0% (n = 44) 94.6% (n = 975) Dead 45.0% (n = 36) 5.4% (n = 56) Introduction Until now there have been few studies concentrating on the diagnostic and prognostic significance of contrast medium S140 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 extravasation site computed tomography (CT). In this study investigated the site and extent of contrast medium extravasat on CT findings and its effect on treatment and predicting clin outcome in trauma patients. Methods Fifty patients admitted to our emergency departm with blunt abdominal trauma showing contrast medium extrava tion on abdominal–pelvic CT scan were included in our study 33 months. Patients were prospectively collected and med records were reviewed and analyzed retrospectively. The patie clinical and laboratory findings, abdominal sonographic (FA findings, and CT findings were reviewed. Extravasation sites w classified as intraperitoneal, retroperitoneal, intrapelvic and correla with post-treatment complications, mortality and morbidity rates. Results The incidence of extravasation site was intraperitoneal in cases (66%), retroperitoneal in 13 cases (26%), and intrapelvic four cases (8%). The frequency of injured vessels show extravasation was 18 (36%) hepatic vessels, nine (18%) sple vessels and six (12%) iliac vessels. There was no correlation betw the extravasation site and ICU or total hospitalization dura (P > 0.523). Sixteen patients with intraperitoneal extravasa required surgical intervention, six patients underwent angiogra with embolization. In patients with retroperitoneal extravasation, n were treated conservatively and two with embolization. Over all th were no significant differences between the extravasation site treatment modality. The intraperitoneal group had the highest morta with 13 deaths (11/33, 39%) and the highest early mortality (10/13, 76%) in the first 24 hours (P = 0.001). Conclusion CT findings in patients with blunt abdominal trau showed no significant correlation between the contrast med extravasation site and treatment modality, ICU hospitalizat duration, or final results. However, patients with intraperiton extravasation required more aggressive transfusion with pac red cells and had a higher mortality rate in the first 24 hours. P352 Damage control orthopedics can improve outcome in trauma patients A Di Filippo, A Circelli, G Cianchi, A Peris Anesthesia and Intensive Care Unit, Florence, Italy Critical Care 2007, 11(Suppl 2):P352 (doi: 10.1186/cc5512) Damage control orthopedics can improve outcome in trauma patients Results There were 94 patients (males = 59; females = 35) between 4 October and 9 December 2006; age range from 1 to 86 years. The ISS ranged from 3 to 75 (ISS > 16 in 54/94 patients). The average time for obtaining LODOX radiographs was 3.5 minutes (range 3–6 min). The mean time in the resuscitation room (during primary and secondary surveys) was 28.7 minutes with the new technique compared with 29 minutes before S141 Introduction Damage control orthopedics (DCO) is a reviewed concept used in major trauma. Advances in critical care Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin management enable surgical stabilization in the early phase of trauma care. Logistical organization and accessibility to several therapeutic solutions can influence a physician’s decisions regarding a trauma patient. The aim of this study is to investigate whether the timing of surgery and method of stabilization in trauma patients with femoral fracture can influence the incidence of pulmonary complication, MOF and the length of stay in the ICU. two groups: group 1 (n = 27), brain death occurred in the first 3 days; group 2 (n = 27), brain death occurred in the days after. Statistics were determined with the Student t and chi-squared tests; P < 0.05 was considered significant. Results The significant differences between the two groups are reported in Table 1. A strict relationship exists between early brain death and prehospital treatment. During the ICU stay low levels of ScVO2 and high levels of glycaemia are related to early brain death. Method In a retrospective study performed at a Level I trauma center, we considered all adult patients with major trauma (ISS > 15) and femoral shaft fracture admitted between January 2003 and July 2006. Patients were separated into two groups according to the management strategies for the femoral fracture: group 1, no surgery within 72 hours after primary admission; group 2, surgical stabilization within 72 hours (DCO). To compare the two groups we considered age, ISS, RTS, TRISS, SAPS II, GCS, comorbidity, and other associated surgery. Table 1 (abstract P353) Results We identified 48 patients, 24 for each group. The groups were comparable regarding all the considered parameters except for GCS at admission (group 1, 8.63 ± 5.12; group 2, 12.2 ± 3.99; P = 0.01) and TRISS (group 1, 62.04 ± 34.55%; group 2, 82.37 ± 18.60%; P = 0.01). We observed in group 2 a significant decrease of mortality (5 vs 0; P = 0.02), incidence of ALI–ARDS (13 vs 4; P = 0.01) and pneumonia (18 vs 6; P = 0.01), a decrease of SOFA score (mean SOFA score: 7.58 ± 4.11 vs 3.97 ± 2.39, P < 0.001; maximum SOFA score: 9.83 ± 4.36 vs 5.62 ± 2.97, P < 0.001; days with SOFA >6: 3.79 ± 3.08 vs 2.16 ± 2.18, P = 0.04). Conclusion The results of the study confirm that prehospital hypotension is the main risk factor for an early evolution to brain death in head trauma. Also, patients that have prolonged hypoperfusion and neurohormonal imbalance after the postresuscitation phase present an increased risk of brain death. P354 P354 Sensitivity and specificity of a triage score dedicated to trauma patients in a tertiary-level hospital: preliminary results P Masturzo1, R Regolo1, G Ferro2, G Nardi3, D Orazi2, V Maggi2 1Seconda Università, Napoli, Italy; 2San Camillo Forlanini, Roma, Italy; 3Ospedale S. Camillo-Forlanini, Roma, Italy Critical Care 2007, 11(Suppl 2):P354 (doi: 10.1186/cc5514) Sensitivity and specificity of a triage score dedicated to trauma patients in a tertiary-level hospital: preliminary results Conclusions We observed an improvement of respiratory parameters and SOFA score in patients treated with DCO. Furthermore, patients with worse neurological conditions at admission do not undergo orthopaedic surgery because it could worsen the cerebral perfusion (risk related to transfer to a far operating room). The physician’s decisions (and therefore the patient’s prognosis), in our experience, are limited by access to optimal therapeutic solutions that could improve the clinical course of the patient. P Masturzo1, R Regolo1, G Ferro2, G Nardi3, D Orazi2, V Maggi2 1Seconda Università, Napoli, Italy; 2San Camillo Forlanini, Roma, Italy; 3Ospedale S. Camillo-Forlanini, Roma, Italy Critical Care 2007, 11(Suppl 2):P354 (doi: 10.1186/cc5514) Introduction The aim of the study was to determine the sensitivity and specificity of the triage criteria adopted for multiple trauma patients in order to activate the Trauma Team in our tertiary-level trauma centre. P353 Methods A cohort study. Between 1 September and 30 November 2006, all trauma patients admitted to the ED triaged red, yellow or green on admission and discharged as a red code from the ED following specific criteria were included. Triage criteria on admission included at least one of the following: GCS < 13, systolic BP > 220 and < 100 mmHg, SaO2 < 95% on oxygen 100% or intubated; clinical signs: penetrating wounds, spinal injury, sternal or flail chest, two long-bone fractures, proximal crash or amputation of limbs, post-traumatic seizures at any time, signs of fracture of the skull; major accident mechanics: fatality in the same vehicle, fall from a height >3 m, prolonged extrication time (>20 min), pedestrian hit by a car, ejection, explosion in a close environment. Severely injured patients at discharge from the ED were defined by: invasive resuscitating procedures (that is, tracheal intubation), invasive life-saving procedures (emergency surgery, defibrillation) and need for admission to the ICU. Sensitivity and specificity of the triage criteria assigned on admission were calculated and compared with the patients that were triaged red at discharge from ED. Head trauma: risk factors for early brain death – our experience P352 Parameters of evaluation were: mortality in the ICU, ICU length of stay, respiratory failure and length of ventilation, and daily SOFA collected for 8 days. Statistics were determined with the Student t and chi-squared tests; P < 0.05 was considered significant. Table 1 (abstract P353) Group 1 (n = 27) Group 2 (n = 27) P Prehospital Hypotension 22 13 <0.05 ICU stay Glycaemia 170.8 ± 49.5 116.6 ± 24.4 <0.05 ScVO2 < 75% 15 7 <0.05 Table 1 (abstract P353) Group 1 (n = 27) Group 2 (n = 27) P Prehospital Hypotension 22 13 <0.05 ICU stay Glycaemia 170.8 ± 49.5 116.6 ± 24.4 <0.05 ScVO2 < 75% 15 7 <0.05 P355 Method Female pigs, 25–30 kg body weight, were used. Retrograde catheterization of the internal jugular vein (SjO2) and laparotomy was performed. A surgical knot 4 mm long was made at the aorta, with a 3.0 diameter stitch. The abdomen was closed. Then a craniotomy and traumatic brain injury (TBI) was made. A regional cerebral blood flow catheter (RoCBF) was placed under the dura. After the TBI the intraabdominal hemorrhage was made by pulling the titch (rupture of the aorta). The animals were assigned into two groups: group A (fluid resuscitation) and group B (hypotensive resuscitation). The animals that survived after 1 hour of hemorrhage were managed by surgical checking and with 1 hour more of fluid resuscitation. P357 Hyperoxemia improves cerebral autoregulation in severe traumatic brain injury R Celis, R Hlatky, C Robertson Baylor College of Medicine, Houston, TX, USA Critical Care 2007, 11(Suppl 2):P357 (doi: 10.1186/cc517) Head trauma: risk factors for early brain death – our experience Out of the 76 triaged red on admission, 53 patients were confirmed at discharge from ED. The specificity is 70%. P356 p y Conclusions Even if major accident mechanics were included in the admission triage criteria, overtriage was limited to 30%. On the other hand, undertriage was approximate to zero, and the only two yellow codes missed were related to miscommunication by the prehospital team. Introduction We examined the efficacy of hypotensive resuscitation, compared with fluid resuscitation, in patients with closed abdominal trauma and coexisting severe head injury. Introduction We examined the efficacy of hypotensive resuscitation, compared with fluid resuscitation, in patients with closed abdominal trauma and coexisting severe head injury. Conjunctival and sublingual microcirculation alterations in head trauma patients with increased intracranial pressure B Atasever, D Gommers, J Bakker Erasmus Medical Center Rotterdam, The Netherlands Critical Care 2007, 11(Suppl 2):P355 (doi: 10.1186/cc5515) B Atasever, D Gommers, J Bakker Erasmus Medical Center Rotterdam, The Netherlands Critical Care 2007, 11(Suppl 2):P355 (doi: 10.1186/cc5515) Introduction Both the conjunctiva and the sublingual tissue have a common blood supply via the common carotid artery trunk. Moreover, the conjunctiva receives blood from the internal carotid artery and the sublingual tissue receives from the external carotid artery. We hypothesized that conjunctival and sublingual microcirculation can be used to evaluate intracranial and extracranial perfusion and to monitor therapy to improve cerebral perfusion pressure in patients after head trauma. Results See Table 1: RoCBF and SjO2 before and after the surgical checking of the hemorrhage. Conclusion In group B there was complete restoration of cerebral blood flow and brain oxygenation, after the surgical checking of hemorrhage. Hypotensive resuscitation causes significant reduction in mortality in patients with closed intraabdominal trauma and coexisting head injury, without putting cerebral function in jeopardy. Methods In three groups of patients with increased intracranial pressure (ICP) (high ICP > 30, medium ICP 20–30 and low ICP < 20) following head trauma, both the conjunctival and sublingual microcirculation was measured using sidestream darkfield imaging (MicroScan®; MicroVision Medical, The Netherlands) to evaluate intracranial and extracranial perfusion. Using microvascular analysis software (MAS®; MicroVision Medical), functional density of small (<20 µm), medium (20–50 µm) and large (>50 µm) microvessels were determined in addition to erythrocyte velocities. Head trauma: risk factors for early brain death – our experience Head trauma: risk factors for early brain death – our experience A Di Filippo1, S Damiani1, M Migliaccio1, M Bonizzoli2, A Peris3 1Anesthesia and Intensive Care Unit, Florence, Italy; 2Careggi Hospital, Florence, Italy; 3Ospedale Firenze, Florence, Italy Critical Care 2007, 11(Suppl 2):P353 (doi: 10.1186/cc5513) Introduction In a group of patients that evolved in brain death after head trauma, we evaluated the risk factors for an early brain death (in the first 3 days) among the parameters collected prehospital, in the emergency room (ER) and during the ICU stay. Method All the consecutive patients admitted to the ER of Careggi Hospital that evolved to brain death after head trauma during the period January 2004–June 2006 were considered (n = 54). The following parameters were considered for the study: prehospital phase: hypoxemia (SaO2 < 95%), hypotension (SAPS II < 90 mmHg), orotracheal intubation, fluids (>1,000 or ≤1,000 ml), and GCS; ER phase (ATLS approach): hypoxemia, hypotension, orotracheal intubation, fluids, GCS, blood lactate, pharyngeal temperature, and ISS; ICU stay: SAPS II, daily SOFA score, blood lactate, core temperature, glycaemia, and ScVO2 (>75% or ≤75%). On the basis of the timing of brain death, the patients were divided into Results During the time span, 5,142 trauma patients were admitted to the ED: 4,884 were triaged green, 182 yellow and 76 were triaged as red. Of the 76 red on admission, 55 patients fulfilled the abovementioned criteria and were confirmed severely injured at discharge from ED. Out of the 55, 53 patients were S142 Available online http://ccforum.com/supplements/11/S2 Table 1 (abstract P356) 5 minutes 15 minutes 45 minutes 5 minutes 15 minutes 45 minutes Baseline before before before after after after Mortality Group A RoCBF (ml/min.100 ml) 31.92 35.47 19.32 5.25*** 100% SjO2 (%) 71.2 32.8 25.7 28.7*** Group B RoCBF (ml/min.100 ml) 30.3 14.2* 14.5* 16.4 33.47 38.24 37.67 50% SjO2 (%) 81.1 25.8*** 22.7*** 24.4*** 38.5** 49.5** 57.1* *P < 0.05, **P < 0.01 and ***P < 0.001 for comparison with baseline. P356 The influence of hypotensive resuscitation in hemorrhagic shock with coexisting severe head injury: an experimental protocol T Vrettos, P Athanasopoulos, N Karageorgos, S Balasis, G Gatzounis, T Siklis, K Filos University of Patras Medical School, Patras, Greece Critical Care 2007, 11(Suppl 2):P356 (doi: 10.1186/cc5516) correctly identified by triage criteria, while two patients were missed. The sensitivity is 96%. P359 Haemostatic activation markers in brain injury for mortality prediction: comparison of blood samples from the jugular bulb and central venous line Haemostatic activation markers in brain injury for mortality prediction: comparison of blood samples from the jugular bulb and central venous line N Baffoun1, C Kaddour1, Z Haddad2, R Souissi1, W Gdoura1, L Skandrani1 1National Institute of Neurology, Tunis, Tunisia; 2CHI St-Cloud, France Critical Care 2007, 11(Suppl 2):P359 (doi: 10.1186/cc5519) N Baffoun1, C Kaddour1, Z Haddad2, R Souissi1, W Gdoura1, L Skandrani1 1National Institute of Neurology, Tunis, Tunisia; 2CHI St-Cloud, France Critical Care 2007, 11(Suppl 2):P359 (doi: 10.1186/cc5519) Hyperoxemia improves cerebral autoregulation in severe traumatic brain injury The neurobehavioral motor outcome was evaluated weekly (for 4 weeks) by performing a neuroscore, and cognitive function was evaluated at 4 weeks postinjury using the Morris water maze. Results Consistently, brain-injured mice receiving C1-INH showed attenuated neurological motor deficits during the 4-week period compared with injured mice receiving saline (Figure 1). At 4 weeks postinjury we observed a trend towards a better cognitive performance in mice receiving C1-INH compared with mice receiving saline (n = 8 per group, P = 0.08). 2 2 2 The ARI (normal 5 ± 1) in these head-injured patients averaged 2.2 ± 1.5 on day 1 and gradually improved over the 10 days of monitoring. The ARI significantly improved with hyperoxemia, during the first 6 days after injury when compared with the ARI measured at normoxemia. The mean left ARI difference during hyperoxia was 0.4069 ± 1.7948 while the right ARI difference was 0.4708 ± 1.8413. The average change in pCO2 during hyperoxia was 35.6468 ± 5.8778. These changes in the ARI during hyperoxia were smaller than those observed during hyper- ventilation. Hyperventilation increased the ARI by average 0.8519 ± 0.2310 on the left and 1.0833 ± 0.4654 on the right. The ARI (normal 5 ± 1) in these head-injured patients averaged 2.2 ± 1.5 on day 1 and gradually improved over the 10 days of monitoring. The ARI significantly improved with hyperoxemia, during the first 6 days after injury when compared with the ARI measured at normoxemia. The mean left ARI difference during hyperoxia was 0.4069 ± 1.7948 while the right ARI difference was 0.4708 ± 1.8413. The average change in pCO2 during hyperoxia was 35.6468 ± 5.8778. These changes in the ARI during hyperoxia were smaller than those observed during hyper- ventilation. Hyperventilation increased the ARI by average 0.8519 ± 0.2310 on the left and 1.0833 ± 0.4654 on the right. Pressure autoregulation was impaired in these head-injured patients. Hyperoxia significantly improved pressure autoregulation. The very small change in pCO2 induced by hyperoxia does not seem to explain this improvement in pressure autoregulation. Vasoconstriction induced by hyperoxia may partially contribute to the improved pressure autoregulation. Conclusion Post-traumatic administration of the endogenous complement inhibitor C1-INH significantly attenuates neurological motor deficits associated with traumatic brain injury. P358 Objective Our aim was the identification of coagulopathy disorders and their relation to outcome in severely head-injured patients. Objective Our aim was the identification of coagulopathy disorders and their relation to outcome in severely head-injured patients. C1-inhibitor attenuates neurobehavioral deficits following controlled cortical impact brain injury in mice a d e e a o o o co e se e e y ead j ed pa e s Patients and methods A prospective study was performed June 2003–March 2004. Included were critically ill patients with isolated closed severe head trauma. Collected data were demographics, management prior to and during ICU hospitalization (sedation, catecolamin drug use, blood product transfusion, intracranial pressure monitoring, neurosurgical emergency surgery, etc.), CT-scan results, daily worst Glasgow Coma Scale score, and admission Simplified Acute Physiology Score II. We inserted an arterial catheter for invasive pressure monitoring, a central venous catheter and a unilateral jugular bulb in front of the most damaged brain hemisphere (cf. CT scan). Jugular bulb thrombosis was prevented by continuous infusion of 2 ml/hour isotonic serum without heparin. Blood samples were obtained simultaneously from the central venous line (K) and jugular bulb (B) at admission, 6 hours, 12 hours, and then in case of neurological aggravation or daily until 5 days. We measured the platelet count, prothrombin time (PT), activated partial thromboplastin time (ACT), fibrinogen concentration (Fib), prothrombin fraction 1+2 (F) and thrombin– antithrombin complex (TAT). During the study only central venous blood samples (PT, ACT, Fib and platelet count) could be available if necessary. Otherwise blood samples were centrifuged and preserved refrigerated for post-hoc analysis. Statistical analysis was by Student’s t test, paired t test for paired results and analysis of variance. Significance was set as P < 0.05. L Longhi1, C Perego2, E Zanier1, F Ortolano1, P Bianchi1, L Bergamaschini1, N Stocchetti3, G De Simoni2 1Milan University, Ospedale Maggiore Policlinico IRCCS, Milano, Italy; 2Mario Negri Institute, Milano, Italy; 3Ospedale Policlinico IRCCS, Milan, Italy Critical Care 2007, 11(Suppl 2):P358 (doi: 10.1186/cc5518) Critical Care 2007, 11(Suppl 2):P358 (doi: 10.1186/cc5518) Introduction The goal of the study was to evaluate the neuro- behavioral effects of the C1-inhibitor (C1-INH), an endogenous inhibitor of complement and contact-kinin pathways, following controlled cortical impact (CCI) brain injury in mice. Figure 1 (abstract P358) Figure 1 (abstract P358) Figure 1 (abstract P358) Results The total n = 19; nine survivors (S) and 10 deaths (NS). Hyperoxemia improves cerebral autoregulation in severe traumatic brain injury The average change in pCO2 during hyper was 35.6468 ± 5.8778. These changes in the ARI du hyperoxia were smaller than those observed during hy ventilation. Hyperventilation increased the ARI by aver 0.8519 ± 0.2310 on the left and 1.0833 ± 0.4654 on the right Pressure autoregulation was impaired in these head-inju patients. Hyperoxia significantly improved pressure autoregula The very small change in pCO2 induced by hyperoxia does seem to explain this improvement in pressure autoregula Vasoconstriction induced by hyperoxia may partially contribut the improved pressure autoregulation. P358 C1-inhibitor attenuates neurobehavioral deficits followin controlled cortical impact brain injury in mice L Longhi1, C Perego2, E Zanier1, F Ortolano1, P Bianchi1, L Bergamaschini1, N Stocchetti3, G De Simoni2 1Milan University, Ospedale Maggiore Policlinico IRCCS, Milan Italy; 2Mario Negri Institute, Milano, Italy; 3Ospedale Policlinico IRCCS, Milan, Italy Critical Care 2007, 11(Suppl 2):P358 (doi: 10.1186/cc5518) Introduction The goal of the study was to evaluate the ne behavioral effects of the C1-inhibitor (C1-INH), an endogen inhibitor of complement and contact-kinin pathways, follow controlled cortical impact (CCI) brain injury in mice. Figure 1 (abstract P358) We prospectively examined 186 (aged 34.4 ± 14.99 years) patients with severe traumatic brain injury (postresuscitation GCS 5.98 ± 3.0957) following admission to the neurosurgical ICU of a level one trauma hospital. Hyperventilation and hyperoxia studies were conducted, recording middle cerebral artery flow velocity and the autoregulation index (ARI) bilaterally and simultaneously at baseline and posthyperventilation (CO2 reactivity = %∆CBF/ ∆pCO2)/hyperoxia (O2 reactivity = ∆PbtO2/∆pO2). Continuous multimodal neuromonitoring, intracranial pressure, mean arterial blood pressure, cerebral perfusion pressure, end-tidal CO2 (ETCO2), PbtiO2, and SjvO2, was recorded. Methods Mice were anesthetized and subjected to CCI brain injury. At 10 minutes postinjury, animals randomly received an intravenous infusion of either C1-INH (15 U) or saline (equal volume, 150 µl). A second group of mice received identical anesthesia, surgery, and saline to serve as uninjured controls. The neurobehavioral motor outcome was evaluated weekly (for 4 weeks) by performing a neuroscore, and cognitive function was evaluated at 4 weeks postinjury using the Morris water maze. Methods Mice were anesthetized and subjected to CCI brain injury. At 10 minutes postinjury, animals randomly received an intravenous infusion of either C1-INH (15 U) or saline (equal volume, 150 µl). A second group of mice received identical anesthesia, surgery, and saline to serve as uninjured controls. Hyperoxemia improves cerebral autoregulation in severe traumatic brain injury Results Conjunctival microcirculatory flow was intermittent in patients with highest ICP, low-continuous in patients with medium ICP, and normal-continuous in patients with lowest ICP. Intra- cranial perfusion pressure was lowest in patients with highest ICP and vice versa. Functional vessel densities in the conjuctiva were in the same range in all three groups. However, the sublingual functional capillary densities were consistently lower in all groups as compared with controls, suggesting an active intracranial and extracranial regional autoregulation. R Celis, R Hlatky, C Robertson Baylor College of Medicine, Houston, TX, USA Critical Care 2007, 11(Suppl 2):P357 (doi: 10.1186/cc517) R Celis, R Hlatky, C Robertson Baylor College of Medicine, Houston, TX, USA Critical Care 2007, 11(Suppl 2):P357 (doi: 10.1186/cc517) The intrinsic autoregulation mechanisms of the cerebral vessels that normally maintain a constant cerebral blood flow (CBF) relatively independently from the cerebral perfusion pressure variations are frequently impaired in the severely traumatized. It has been shown that hyperventilation can restore the cerebral autoregulation and controlling intracranial pressure, but much less attention has been given to the effects of the hyperoxic state in the restoration of cerebral autoregulation. The purpose of the study was to compare the autoregulatory response to hyperventilation vs hyperoxia in severe traumatic brain injury. Conclusion Conjunctival microcirculatory flow analysis reflects alterations in cranial perfusion pressure and might be a possible noninvasive endpoint to monitor cerebral perfusion and therapy. S143 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin We prospectively examined 186 (aged 34.4 ± 14.99 ye patients with severe traumatic brain injury (postresuscitation G 5.98 ± 3.0957) following admission to the neurosurgical ICU level one trauma hospital. Hyperventilation and hyperoxia stu were conducted, recording middle cerebral artery flow velocity the autoregulation index (ARI) bilaterally and simultaneousl baseline and posthyperventilation (CO2 reactivity = %∆C ∆pCO2)/hyperoxia (O2 reactivity = ∆PbtO2/∆pO2). Continu multimodal neuromonitoring, intracranial pressure, mean art blood pressure, cerebral perfusion pressure, end-tidal C (ETCO2), PbtiO2, and SjvO2, was recorded. The ARI (normal 5 ± 1) in these head-injured patients avera 2.2 ± 1.5 on day 1 and gradually improved over the 10 day monitoring. The ARI significantly improved with hyperoxe during the first 6 days after injury when compared with the measured at normoxemia. The mean left ARI difference du hyperoxia was 0.4069 ± 1.7948 while the right ARI difference 0.4708 ± 1.8413. P360 P360 Decreased adrenal reserve after etomidate use in moderate and severe traumatic brain injuries: clinical implications P Archambault, C Dionne, G Lortie, F LeBlanc, A Rioux, G Larouche Université Laval, Ottawa, Canada Critical Care 2007, 11(Suppl 2):P360 (doi: 10.1186/cc5520) Introduction Etomidate is frequently used as an anesthetic induction agent for the intubation of head trauma patients. The clinical impacts of its effects on adrenal function are still debated. Therefore, the primary objective of this study was to determine the length and the importance of relative adrenal insufficiency (RAI) induced by etomidate in moderate and severe head trauma patients. The secondary objective was to determine etomidate’s impacts on mortality and morbidity. Conclusions These results suggest that etomidate decreases the adrenal reserve up to 24 hours after a single dose used for the intubation of traumatic brain injury victims. A larger randomized controlled trial is needed to further assess etomidate’s impacts on morbidity and mortality. P361 Methods This was a prospective cohort study. Eligible participants were intubated moderate to severe head trauma victims aged ≥16 years, admitted to a tertiary neurosurgical reference center between August 2003 and November 2004. The induction agent was chosen by the physician, without any interference by the research team. ACTH stimulation tests (250 µg) were performed on each participant 24, 48 and 168 hours after intubation. Responses to these tests were compared between patients having received etomidate and those having received other induction agents. RAI was defined as an increase in cortisol levels <248.4 nmol/l (9 µg/dl), measured 30 and 60 minutes after the ACTH test. Logistic and linear regression models were used to compare the two groups of patients on outcomes while taking confounding variables into account. Differential effects of in vitro norepinephrine on platelets isolated from severely traumatic brain injured patients Differential effects of in vitro norepinephrine on platelets isolated from severely traumatic brain injured patients Differential effects of in vitro norepinephrine on platelets isolated from severely traumatic brain injured patients J Stover, C Tschuor, L Asmis, J Fehr, R Stocker University Hospital Zürich, Switzerland Critical Care 2007, 11(Suppl 2):P361 (doi: 10.1186/cc5521) J Stover, C Tschuor, L Asmis, J Fehr, R Stocker University Hospital Zürich, Switzerland Critical Care 2007, 11(Suppl 2):P361 (doi: 10.1186/cc5521) y ritical Care 2007, 11(Suppl 2):P361 (doi: 10.1186/cc55 Introduction Norepinephrine used in clinical routine to increase cerebral perfusion following severe traumatic brain injury (TBI) may activate α2-adrenergic receptors on platelets, thereby possibly promoting formation of microthrombosis and inducing additional brain injury. Methods Arterial and jugular venous platelets isolated from nor- epinephrine-receiving TBI patients (n = 11) and healthy volunteers (n = 36) (cubital vein) were stimulated in vitro with increasing Results Of the 94 patients eligible for this study, 40 (43%) gave consent for the ACTH test. Fifteen patients received etomidate and Available online http://ccforum.com/supplements/11/S2 difference was observed for other tests between B vs K and S vs NS for different paired tests. 25 received other induction agents. At 24 hours, there were no differences in the risk of RAI between groups (OR: 1.8, 95% CI: 0.2–14.3, P = 0.59). However, at 24 hours, subjects who had received etomidate presented a significantly lower response to ACTH (adjusted mean: 299.7 nmol/l, 95% CI: 214.7–384.8 versus 503.8 nmol/l, 95% CI: 441.8–565.7, P = 0.002). At 48 and 168 hours, this difference disappeared. For all eligible patients (n = 94), there was a nonsignificant trend to an increased risk in mortality in the etomidate group (adjusted OR: 4.8, 95% CI: 0.6–35.9, P = 0.13). Etomidate was also associated with an increased risk of pneumonia (adjusted OR: 3.0, 95% CI: 1.0–8.7). The adjusted length of stay in the ICU was not different between groups. At discharge, the adjusted motor Functional Independence Measure (FIM) score was significantly lower for subjects in the etomidate group (32 versus 56, P = 0.002), but the adjusted cognitive FIM score was not significantly different in the etomidate group (35 versus 46, P = 0.15). 25 received other induction agents. At 24 hours, there were no differences in the risk of RAI between groups (OR: 1.8, 95% CI: 0.2–14.3, P = 0.59). However, at 24 hours, subjects who had received etomidate presented a significantly lower response to ACTH (adjusted mean: 299.7 nmol/l, 95% CI: 214.7–384.8 versus 503.8 nmol/l, 95% CI: 441.8–565.7, P = 0.002). At 48 and 168 hours, this difference disappeared. For all eligible patients (n = 94), there was a nonsignificant trend to an increased risk in mortality in the etomidate group (adjusted OR: 4.8, 95% CI: 0.6–35.9, P = 0.13). Etomidate was also associated with an increased risk of pneumonia (adjusted OR: 3.0, 95% CI: 1.0–8.7). The adjusted length of stay in the ICU was not different between groups. At discharge, the adjusted motor Functional Independence Measure (FIM) score was significantly lower for subjects in the etomidate group (32 versus 56, P = 0.002), but the adjusted cognitive FIM score was not significantly different in the etomidate group (35 versus 46, P = 0.15). Conclusion Procoagulant factors (F and TAT) are valuable prognostic factors at day 1 in closed isolated severe head trauma. P358 No differences between S and NS in demographics, management modalities, admission GCS score (7 ± 3), CT scan, and SAPS II (27 ± 10 vs 30 ± 17, P = 0.69). The B vs simultaneous K platelet count was significantly lower in all drawn blood samples, with a trend to decrease over time. S vs NS at day 2 and day 3: 191 ± 60 vs 125 ± 35 (P = 0.017). The admission B thrombin fraction was higher in NS (1,000 ± 209 vs 460 ± 294, P = 0.014). The B day 1 TAT was higher in NS: 45 ± 20 vs 9.6 ± 12 (P = 0.02). No S144 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 P362 Patients We enrolled consecutive patients >12 years of age expected to stay in the ICU >48 hours. We excluded patients on systemic anticoagulation and patients with pulmonary embolism (PE) or deep venous thrombosis (DVT) on admission to the ICU or diagnosed within 24 hours of ICU admission. We recorded a priori defined VTE risk factors at baseline and daily. Our ICU implements a protocol for thromboprophylaxis, which is based on the evidence- based ACCP guidelines. The primary endpoint was the develop- ment of PE or DVT during ICU stay. We used multivariate regression analysis to determine independent predictors of VTE. Patients We enrolled consecutive patients >12 years of age expected to stay in the ICU >48 hours. We excluded patients on systemic anticoagulation and patients with pulmonary embolism (PE) or deep venous thrombosis (DVT) on admission to the ICU or diagnosed within 24 hours of ICU admission. We recorded a priori defined VTE risk factors at baseline and daily. Our ICU implements a protocol for thromboprophylaxis, which is based on the evidence- based ACCP guidelines. The primary endpoint was the develop- ment of PE or DVT during ICU stay. We used multivariate regression analysis to determine independent predictors of VTE. Results Among 277 patients with a mean APACHE II score of 25 (+9), the incidence of VTE was 7.2% (95% CI 4.5–11). We identified three independent risk factors for ICU-acquired venous thromboembolism: stroke (OR 13.5, 95% CI 1.9–91.19, P = 0.008), femur fracture (OR 4.5, 95% CI 1.18–17.10, P = 0.03), and ICU length of stay (OR for each day increment 1.08, 95% CI 1.03–1.13, P = 0.002). After adjustment for APACHE II score, VTE was an independent predictor of mortality (OR 3.85, 95% CI 1.11–13.29, P = 0.03). P363 P363 norepinephrine concentrations (10 nM to 100 µM); thrombin receptor activator peptide (TRAP) served as positive control. P-selectin expression was determined by flow cytometry (FACS). norepinephrine concentrations (10 nM to 100 µM); thrombin receptor activator peptide (TRAP) served as positive control. P-selectin expression was determined by flow cytometry (FACS). Results Following TBI, the number of unstimulated P-selectin- positive platelets was significantly decreased in the second week by 60%. During the first week, the in vitro stimulatory effect was significantly reduced; in the second week, however, norepinephrine-mediated effects exceeded changes in controls and the first week without a difference between arterial and jugular venous platelets (Figure 1). Ultrasound evaluation and risk factors for deep venous thrombosis in the intensive care unit Ultrasound evaluation and risk factors for deep venous thrombosis in the intensive care unit M Boddi1, G Palano1, L Tini2, E Lucente1, S Berardino1, G Gensini1, A Peris3 1Department of Medical and Surgical Critical Care, Careggi Teaching Hospital, Florence, Italy; 2Department of Emergency, Careggi Teaching Hospital, Florence, Italy; 3Ospedale Firenze, Florence, Italy Critical Care 2007, 11(Suppl 2):P362 (doi: 10.1186/cc5522) Results Among 277 patients with a mean APACHE II score of 25 (+9), the incidence of VTE was 7.2% (95% CI 4.5–11). We identified three independent risk factors for ICU-acquired venous thromboembolism: stroke (OR 13.5, 95% CI 1.9–91.19, P = 0.008), femur fracture (OR 4.5, 95% CI 1.18–17.10, P = 0.03), and ICU length of stay (OR for each day increment 1.08, 95% CI 1.03–1.13, P = 0.002). After adjustment for APACHE II score, VTE was an independent predictor of mortality (OR 3.85, 95% CI 1.11–13.29, P = 0.03). Introduction Critically ill patients have a high risk of deep venous thrombosis (DVT); however, data about prevalence and specific risk factors in the ICU are conflicting and the prophylaxis strategies are still debated. The aim of this study is to evaluate the prevalence and risk factors in an ICU dealing with trauma and major surgery patients. Methods We analyzed retrospectively data from 142 patients (56 ± 4.8 years) admitted to the ICU from December 2004 to December 2005. We recorded the history, diagnosis, SAPS II, length of stay and major surgery. All patients received standard prophylaxis (LMWH and/or mechanical device). For DVT diagnosis, three compression ultrasound examinations were performed (a) within 48 hours from admission, (b) between the 7th and 10th days, and (c) between the 13th and 16th days. The prevalence of DVT and risk factors were analyzed in the whole population and in the following four groups: ≤40 years, 41–59 years, 60–74 years, and ≥75 years. Statistics were determined using the Wilcoxon and Mann–Whitney tests and one-way analysis of variance on SPSS; P < 0.5 was considered significant. Conclusions VTE is relatively common complication in critically ill patients and is associated with significant mortality. Longer ICU length of stay, stroke and femur fracture are independent predictors for VTE. These findings suggest the need for more effective prophylactic strategies in critically ill patients, especially those at higher risk. Acknowledgement Sponsored by Sanofi-Aventis. Venous thromboembolism in critically ill patients: incidence and risk factors Results Following TBI, the number of unstimulated P-selectin- positive platelets was significantly decreased in the second week by 60%. During the first week, the in vitro stimulatory effect was significantly reduced; in the second week, however, norepinephrine-mediated effects exceeded changes in controls and the first week without a difference between arterial and jugular venous platelets (Figure 1). S Al-Qahtani, Y Arabi, A Aldawood KIing Abdulaziz Medical City, Riyadh, Saudi Arabia Critical Care 2007, 11(Suppl 2):P363 (doi: 10.1186/cc5523) Objective Despite the high risk of venous thromboembolism (VTE) in ICU patients, only few studies have examined this group of patients systematically. The objective of this study is to examine the incidence and risk factors of VTE among critically ill patients. Conclusion Clinically relevant norepinephrine concentrations are <25 nM. The present in vitro effects occurred at concentrations >500 nM. Thus, a clinically relevant impact appears doubtful. Design A prospective cohort study. Setting A closed university-affiliated ICU in a medical–surgical ICU in the Kingdom of Saudi Arabia. Figure 1 (abstract P361) Figure 1 (abstract P361) Changes in P-selectin expression in isolated platelets stimulated in vitro with norepinephrine or TRAP. +P < 0.001 vs low-dose norepinephrine; *P < 0.001 vs controls; #P < 0.001 vs first week. Changes in P-selectin expression in isolated platelets stimulated in vitro with norepinephrine or TRAP. +P < 0.001 vs low-dose norepinephrine; *P < 0.001 vs controls; #P < 0.001 vs first week. S145 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin P364 Cardiopulmonary bypass and recombinant plasminogen activator for treatment of experimental fatal pulmonary embolism g Results One hundred (70%) patients were admitted after trauma, 15 (11%) after surgery, 27 (19%) had medical disease. The mean SAPS II score was 45 ± 15.8 and the mean length of stay was 16 ± 9.84 days. Forty-six patients (32.4%) underwent major surgery following the admission. The overall prevalence of DVT was 17.6% (25/142), with the highest value (24.2%) in the 41–59 year group and the lowest (12.5%) in the >75 year group. DVT was diagnosed in 12/25 (48%) patients within 48 hours from ICU admission and 7/12 (58.3%) had direct venous injury. DVT was diagnosed in the remaining patients after 10 days. We found a strong relationship (P < 0.06) between the length of stay and DVT in patients <40 years. No significant differences were found regarding SAPS. Introduction Treatment of acute pulmonary embolism (PE), which causes life-threatening cardiovascular collapse, consists of cardio- pulmonary bypass (CPB) and surgical embolectomy. In the clinical practice we have treated three such patients successfully with CPB but instead of performing embolectomy, administered recombinant plasminogen activator (rt-PA). We studied the circulatory and respiratory effects of this combined therapy in a swine model of fatal PE. Introduction Treatment of acute pulmonary embolism (PE), which causes life-threatening cardiovascular collapse, consists of cardio- pulmonary bypass (CPB) and surgical embolectomy. In the clinical practice we have treated three such patients successfully with CPB but instead of performing embolectomy, administered recombinant plasminogen activator (rt-PA). We studied the circulatory and respiratory effects of this combined therapy in a swine model of fatal PE. Conclusions In our experience, DVT prevalence showed a bimodal occurrence with a first short-term peak, associated with traumatic or surgical direct venous injury, and a medium-term peak, related to an ICU stay >10 days. We therefore oriented the surveillance to the two periods of higher DVT prevalence and we established a training program for the intensivists to improve DVT detection, relieving the workload of the ultrasound physician. Methods Seven pigs (90 kg) were i.v. anesthetized, muscle relaxed, tracheally intubated and mechanically ventilated (FiO2 1.0). Fibrinolysis during cardiopulmonary bypass detected with thromboelastography R Hájek, J Ruþièková, I Fluger, P Nemec, V Bruk University Hospital, Olomouc, Czech Republic Critical Care 2007, 11(Suppl 2):P366 (doi: 10.1186/cc5526) Results Five animals developed ventricular fibrillation, while one animal maintained sinus rhythm. After 2 hours all animals had an atrial rhythm. All animals were weaned off CPB and survived until the experiment ended. Values before and after CPB (median and range): MAP (mmHg) 101 (86, 109) and 75 (46, 106); CO (l/min) 6.7 (4.3, 11) and 6.2 (3.6, 7.8); MPAP (mmHg) 22 (19, 36) and 44 (31, 82) (P < 0.05); ETCO2 (kPa) 5.6 (4.3, 6.5) and 2.7 (2.4, 3.4) (P < 0.05); PaCO2 (kPa) 6.2 (5.2, 7.2) and 6.1 (4.8, 7.3); PaO2 (kPa) 60 (50, 68) and 55 (30, 64). Background Fibrinolysis is a common haemostatic abnormality during cardiopulmonary bypass (CPB). Thromboelastography (TEG) is a good method to detect both types of fibrinolysis. Methods Four hundred and ninety-nine patients during mild hypothermic CPB and elective surgery were monitored with TEG (first – after the induction, second – after rewarming, third and fourth – at the end of surgery native and heparinase). No prophy- lactic antifibrinolytics were used. The data of the study group were compared with a control group of 475 patients monitored only with laboratory tests (fibrin degradation products (FDP) and D-dimers). Peroperative and 24 hour postoperative bleeding, number of transfusions, aprotinin therapy and reexploration were recorded. Correlations between the presence of fibrinolysis and blood loss and transfusion therapy and between aprotinin administration and blood loss and number of transfusions were evaluated. Conclusion Although there were signs – that is, lower ETCO2 and higher MPAP – that the massive clots were not fully dissolved after 185 minutes, this study shows that fatal PE might be treated effectively with CPB combined with simultaneous thrombolytic therapy. P364 A large-bore catheter (8.5 mm ID) was inserted in the right superior vena cava (for injection of preformed blood clots) and large-bore catheters were inserted in the inferior vena cava via the S146 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 femoral vein and in the aorta via the femoral artery (for accessing CPB). We measured the mean arterial pressure (MAP), cardiac output (CO), blood gases, pulmonary artery pressure measurement (MPAP), end-tidal CO2 (ETCO2) and blood gases. Then 100–300 ml preformed blood clot was injected until systemic circulation ceased (systolic AP < 25 mmHg) and a 5 minute interval was allowed before start of CPB (flow rate of 4–7 l/min). Heparin 10,000 IE was given i.v., and rt-PA 10 mg as an i.v. bolus followed by an i.v. infusion of 90 mg during 2 hours. If ventricular fibrillation occurred, cardioversion was performed. After 145 minutes CPB was weaned off, and after a further 40 minutes the experiment was ended. femoral vein and in the aorta via the femoral artery (for accessing CPB). We measured the mean arterial pressure (MAP), cardiac output (CO), blood gases, pulmonary artery pressure measurement (MPAP), end-tidal CO2 (ETCO2) and blood gases. Then 100–300 ml preformed blood clot was injected until systemic circulation ceased (systolic AP < 25 mmHg) and a 5 minute interval was allowed before start of CPB (flow rate of 4–7 l/min). Heparin 10,000 IE was given i.v., and rt-PA 10 mg as an i.v. bolus followed by an i.v. infusion of 90 mg during 2 hours. If ventricular fibrillation occurred, cardioversion was performed. After 145 minutes CPB was weaned off, and after a further 40 minutes the experiment was ended. procoagulant pathways. Although fibrinolysis was activated, the inhibition of fibrinolysis was more pronounced at the same time. The coagulation inhibitors and TAT levels seem to be early predictors of ICU mortality. Early coagulation alterations in intensive care unit burn patients A Lavrendieva1, A Parlapani2, O Thomareis2, V Soulountsi1, M Bitzani1 1G Papanikolaou Hospital, Thessalonki, Greece; 2Aristotelian University, Thessaloniki, Greece Critical Care 2007, 11(Suppl 2):P365 (doi: 10.1186/cc5525) al Care 2007, 11(Suppl 2):P365 (doi: 10.1186/cc5525) Introduction The aim of the present study was to examine the coagulation status of patients in the early postburn period. Introduction The aim of the present study was to examine the coagulation status of patients in the early postburn period. Method Coagulation and fibrinolysis parameters – antithrombin III (ATIII), protein C (PrC), free protein S (PrS), plasminogen activator inhibitor 1 (PAI-1), tissue plasminogen activator (t-PA), thrombin/ antithrombin complexes (TAT), plasmin/α2-antiplasmin complexes (PAP), fibrin degradation products (F1.2) – were measured at ICU admission and daily thereafter for 7 postburn days. Conclusion Fibrinolysis was usually not associated with serious bleeding. There was no positive effect of aprotinin to reduce bleeding or transfusion therapy. FDP and D-dimers are not useful to detect fibrinolysis in cardiac surgery. Results Forty-five patients were screened (nine nonsurvivors and 36 survivors). All patients had a severe deficiency of the coagulation inhibitors on admission. Normalization of these levels in survivors was observed at day 5 for ATIII and PrC, and at day 7 for PrS. All patients had elevated levels of TAT during the investigation period, but survivors had significantly lower levels at day 7 postburn (6.2 ± 4.9 vs 11.4 ± 4.5 µg/l, P < 0.001). PAP levels were within the physiological range in both groups at day 1, remained low in survivors, but raised significantly in nonsurvivors at day 7 (19.3 ± 14 vs 80.9 ± 10.4 µg/l, P = 0.003). The t-PA levels were elevated permanently only in nonsurvivors. PAI-1 levels were increased at day 1 in both groups, but returned to normal values at day 5 in survivors. The degree of PAI-1 activation was significantly higher than this of t-PA. The F1.2 levels were permanently elevated and there was no statistically significant difference in both groups. A logistic regression analysis revealed that ATIII and PrS at days 3, 5 and 7, Pr C at days 5 and 7 and TAT at day 7 were independent predictors of ICU death. P365 Results The frequency of fibrinolysis measured with TEG: before surgery – primary 3.2%/secondary 3.4%; during CPB – 18.8%/ 0.6%; after surgery – 7%/1.4% (native), 5.6%/0.6% (heparinase). Positivity of fibrinolysis detected with laboratory tests was 100%. The TEG parameter of fibrinolysis (LY30) was significantly increased during CPB. The frequency of aprotinin administration was 12% TEG, 10.7% control. No correlation between positivity of fibrinolysis and peroperative/postoperative blood loss and red blood cells (RBC) and fresh frozen plasma (FFP) transfusions were recorded. No correlation between aprotinin administration and peroperative/postoperative blood loss and RBC transfusion were recorded. Positive correlation between aprotinin administration and FFP transfusion were recorded Early coagulation alterations in intensive care unit burn patients P366 Fibrinolysis during cardiopulmonary bypass detected with thromboelastography Fibrinolysis during cardiopulmonary bypass detected with thromboelastography P368 Low-frequency hemoviscoelastography: a new method of diagnostics for coagulation disorders after abdominal surgery for cancer O Tarabrin, A Simovskykh, V Mazur, A Suhanov Odessa Medical University, Marine Central Hospital, Odessa, Ukraine Critical Care 2007, 11(Suppl 2):P368 (doi: 10.1186/cc5528) Low-frequency hemoviscoelastography: a new method of diagnostics for coagulation disorders after abdominal surgery for cancer Objective Cardiac surgery, in particular when done with cardio- pulmonary bypass (CPB), is frequently associated with excessive intraoperative and postoperative bleeding. Here we employed the Technothrombin® thrombin generation assay (TGA; Technoclone) to monitor changes in perioperative haemostasis. O Tarabrin, A Simovskykh, V Mazur, A Suhanov Odessa Medical University, Marine Central Hospital, Odessa, Ukraine Critical Care 2007, 11(Suppl 2):P368 (doi: 10.1186/cc5528) Methods One hundred and forty-eight patients (age 66.0 ± 9.8 years; 103 males, 45 females) with elective cardiac surgery and a CPB time >45 minutes (mean 114 ± 56 min) were enrolled. Arterial blood samples were obtained preoperative, postoperative and 14–18 hours postoperative and centrifuged within 30 minutes after withdrawal, for 5 minutes at 5,000 x g. Plasma samples were stored until analysis at –80°C. Thrombin generation (TG) induced by the TGA RC low reagent (71.6 pM tissue factor) was measured in 96-well multiplates using a FLUOstar OPTIMA fluorescence reader (MWG Labtech). Critical Care 2007, 11(Suppl 2):P368 (doi: 10.1186/cc5528) Background Venous thromboembolism is one of the most common complications seen in cancer patients and may be due to the hypercoagulable state of the malignancy and to its surgical treatment. Despite clinical and laboratory evidence of perioperative hypercoagulability, there are no consistent data evaluating the extent, duration, and specific contribution of platelets and pro- coagulatory proteins by in vitro testing. Results Due to cardiac surgery, the lag-phase and time-to-peak of TG increased by 45% and 35%, respectively. In parallel, the peak thrombin concentration and maximum slope decreased by 42% and 51%, respectively (P < 0.000001). Both the lag-phase and time-to-peak returned to basal values within 14–18 hours postoperative, but the peak thrombin and maximum slope of TG rose above the preoperative values (+39% and +68%, P < 0.0005). The on-pump time was positively correlated with lag phase and time to peak and negatively correlated with peak thrombin and maximum slope of TG when measured at 14–18 hours postoperative, but there was no correlation at early postoperative. P367 ROTEM® thrombelastometry in on-pump cardiac surgery patients W Loesche, M Reinhöfer, C Macholdt, M Brauer, D Barz, J Gummert, K Reinhart, G Marx University Hospital Jena, Germany Critical Care 2007, 11(Suppl 2):P367 (doi: 10.1186/cc5527) W Loesche, M Reinhöfer, C Macholdt, M Brauer, D Barz, J Gummert, K Reinhart, G Marx University Hospital Jena, Germany Critical Care 2007, 11(Suppl 2):P367 (doi: 10.1186/cc5527) Objective On-pump cardiac surgery is frequently associated with intraoperative and postoperative bleeding. ROTEM® is a point-of- care method that reflects more closely than classical coagulation tests the in vivo haemostatic activity and the contribution of fibrinogen and platelets to clot formation. Methods Two hundred and thirty-two patients (age 67 ± 10 years) with elective cardiac surgery and an on-pump time >45 minutes (mean 112 ± 52 min) were enrolled. Preoperative, intraoperative and postoperative blood samples were taken from an arterial catheter. The ROTEM® system and test kits (INTEM/EXTEM = Conclusion Our findings indicate the early postburn dysregulation of the hemostatic balance characterized by the activation of S147 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin was a 14% perioperative increase of standard MA, corresponding to a 48% increase of Gt (P < 0. 05) and an 80–86% contribution of the calculated Gp to Gt. We conclude that serial standard TEG and the HVG viscoelastic test may reveal the independent contribution of platelets and procoagulatory proteins to clot strength. Using multiple linear regression, all coagulation, TEG and HVG variabilities were used to model postoperative hyper- coagulation. Results showed that some components of the TEG failed to identify hypercoagulation (r < 0.2, P > 0.75). However, three components of the routine coagulation assay, including bleeding time, prothrombin time, and platelet count, could be modeled to show prolonged postoperative hypercoagulability (P < 0.01). We conclude that all components of the HVG test reflect postoperative coagulopathies; these results suggest that it may be useful in determining the coagulation status of cancer patients perioperatively. platelets) were from Pentapharm (Munich, Germany). Results The clot formation time (CFT) and maximum clot firmness (MCF), but not clotting time (CT), were strongly correlated with the fibrinogen level and platelet count. Surgery significantly decreased the ROTEM haemostatic activity, but normalised in most patients within 14–18 h postoperation. Lowest haemostatic activity (dramatic increase in CT and CFT, decrease in MCF) was seen when patients were conditioned for cardiopulmonary bypass (CPB). Thrombin generation in on-pump cardiac surgery patients W Loesche, V König, V Oberle, M Reinhöfer, D Barz, J Gummert, G Marx University Hospital Jena, Germany Critical Care 2007, 11(Suppl 2):P369 (doi: 10.1186/cc5529) P367 When connected to CPB, the CT and CFT turned to recover, but MCF in EXTEM remained unchanged and MCF in FIBTEM declined further indicating continuous fibrinogen consumption. In 12.5% of our patients, postoperative MCF in FIBTEM was reduced to <9 mm indicating a need for fibrinogen substitution. Low postoperative activity in ROTEM® was associated with high postoperative blood loss. The positive predictive value and specificity of FIBTEM were clearly superior to those of the APTT or prothrombin time. Up to 50% of patients had an increased haemostatic activity in preoperative ROTEM®, and this was associated with high CRP levels and intraoperative blood loss. Conclusion Postoperative hypercoagulability, occurring for at least 1 week after major cancer abdominal surgery, may be demonstrated by the HVG viscoelastic test. This hypercoagulability is not reflected completely by standard coagulation monitoring and TEG, and seems to be predominantly caused by increased platelet reactivity. The HVG viscoelastic test provides a fast and easy to perform bedside test to quantify in vitro hemocoagulation. Conclusions ROTEM® is a valuable tool to monitor peri- operative haemostasis. The decreases in haemostatic activity and postoperative bleeding are probably due to anticoagulant therapy as well as fibrinogen and platelet consumption. An increased preoperative haemostatic activity is probably due to an acute phase reaction associated with advanced athero- sclerosis, and the high intraoperative bleeding in these patients might be due to the atherosclerotic vessels rather than due to an insufficient haemostasis. P370 There were 12 minor bleeding events, occurring mostly during the maintenance infusion rate adjustment period and which responded to transient interruption and/or lowering of the infusion rate. Eleven nonfatal major bleeding events occurred (four due to procedural errors) and eight fatal major bleeds, two of which occurred 3 days and 8 days after Orgaran® discontinuation. Activated clotting time (ACT) measuring devices used simultaneously do not produce correlating ACT values I Lorenz, J Walde, C Schnuerer, C Velik-Salchner, P Muessigang, A Jeller, J Engel, R Gruber, C Falbesoner, C Kolbitsch University Innsbruck, Austria Critical Care 2007, 11(Suppl 2):P370 (doi: 10.1186/cc5530) Plasma anti-FXa levels were reported for 38 patients. During seven of the eight fatal bleeding episodes the plasma anti-FXa levels were ≥0.8 U/ml in three patients and 0.31–0.66 U/ml (that is, within the target range) in the other four patients. The highest anti- FXa response of 2.00 U/ml was associated with minor bleeding from an angiomatous malformation and stopped when the Orgaran® dose was reduced. However, of the 11 patients receiving >400 U/hour, four suffered major bleeding (three fatal) and two developed minor bleeding. Most of these patients received continuous arterio-venous haemodiafiltration treatment, which may have been a contributory factor. Introduction The lack of a ‘gold standard’ activated clotting time (ACT) measuring device gives rise to the broad range of ACT measuring devices currently on the market. The present study focused on the inter-device and intra-device differences (for example, reproducibility of ACT measurement) in four different ACT measuring systems. Methods (1) Hemochron celite tubes, (2) Aktalyke celite tubes, (3) Actalyke ACT-Max tubes and (4) Hemochron Junior low-range (LR) or high-range (HR) cartridges were simultaneously filled with blood drawn (n = 3,997) at baseline, at 3 minutes following administration of heparin (300 IU/ kg), 5 minutes after starting cardiopulmonary bypass (CPB), every 30 minutes during CPB and thereafter at 15 minutes following protamine administration. Conclusions We recommend that maintenance Orgaran® infusion rates ≥400 U/hour should be avoided unless serious circuit clotting is grossly affecting the haemofilter life. The infusion rate should be monitored clinically; that is, on the basis of bleeding and circuit clotting rather than the patients’ plasma anti-FXa responses. Results The ACT values measured simultaneously using four different ACT measuring devices did not correlate with each other at any measurement time. P371 Introduction Heparin-induced thrombocytopenia (HIT) presents with thrombocytopenia and high risk for venous and/or arterial thrombosis, as an adverse effect of heparin (especially unfractioned). Objective To evaluate the incidence of positive heparin antibody test in a multidisciplinary ICU for the time period from 1 January 2006 to 30 November 2006. Introduction Heparin-induced thrombocytopenia (HIT) presents with thrombocytopenia and high risk for venous and/or arterial thrombosis, as an adverse effect of heparin (especially unfractioned). Objective To evaluate the incidence of positive heparin antibody test in a multidisciplinary ICU for the time period from 1 January 2006 to 30 November 2006. Available online http://ccforum.com/supplements/11/S2 Conclusions The data provide clear evidence for a marked decrease of TG during cardiac surgery followed by an excess restoration in the postoperative phase. Factors released from platelets and leukocytes (procoagulant microvesicles?) might contribute to the enhanced TG observed at 14–18 hours postoperative. Conclusions The data provide clear evidence for a marked decrease of TG during cardiac surgery followed by an excess restoration in the postoperative phase. Factors released from platelets and leukocytes (procoagulant microvesicles?) might contribute to the enhanced TG observed at 14–18 hours postoperative. A variety of continuous extracorporeal haemofiltration circuits was used for from 1 to 39 days (median 7 days). The Orgaran® dosing schedule was usually initiated with a 2,000–2,500 U intravenous bolus injection. After two step-down dose periods the subsequent maintenance infusion was usually titrated according to each patient’s thromboembolic and bleeding risk status. Hence most patients received 100–400 U/hour, but 11 patients required up to 600 U/hour temporarily to control extracorporeal circuit clotting. P372 High incidence of positive heparin antibodies in a multidisciplinary intensive care unit P Renieris, V Gerovasili, M El Ali, T Theodoridis, M Poriazi, A Bouhla, V Markaki, S Mentzelopoulos, D Zervakis, C Roussos, S Nanas National and Kapodistrian University of Athens, Greece Critical Care 2007, 11(Suppl 2):P372 (doi: 10.1186/cc5532) Conclusion The Hemochron Junior ACT measuring device showed the smallest intra-device measuring error. No correlation, however, could be established between ACT values measured with the four devices tested. P370 Reproducibility of ACT measurement (for example, intra-device difference) was, in descending order, best for Hemochron Junior, Actalyke ACT-Max, Hemochron celite and Aktalyke celite. P368 With respect to classical coagulation parameters, significant correlations were observed between TG and activated partial thromboplastin time at preoperative and 14–18 hours post- operative, and between TG and prothrombin time at postoperative (P < 0.025–0.001). At 14–18 hours postoperative there was a significant correlation of TG with platelet as well as leukocyte counts (P < 0.025). Materials and methods Patients undergoing planned curative open surgery for abdominal cancer received MEDNORD (Ukraine Co analyser) analysis (HVG), a viscoelastic test that measures clot formation and includes information on the cellular, as well as the plasmatic coagulation, system. We examined the efficacy of a variety of coagulation tests. A complete coagulation screen, activated clotting time, thromboelastography (TEG) and hemo- viscoelastography (HVG) were performed before surgery, at the end of surgery, and on postoperative days 1, 2, 3, and 7; they were analyzed for the reaction time and the maximal amplitude (MA). We tested the hypothesis that the parallel use of standard TEG and HVG can assess postoperative hypercoagulability and can estimate the independent contribution of procoagulatory proteins and platelets. Results and discussion We calculated the elastic shear modulus of standard MA (Gt) and HVG MA (GH), which reflect the total clot strength and procoagulatory protein component, respectively. The difference was an estimate of the platelet component (Gp). There S148 Available online http://ccforum.com/supplements/11/S2 P373 The antibody determination was performed using commercially available ELISA kits. In the functional assays, heparin-induced platelet activation/aggregation (HIPA) and a flow cytometric technique for the detection of platelet microparticles released (platelet microparticle assay) were included. Conclusion Exclusion of female-donor FFP was associated with a statistically significant reduction in the incidence of ALI in patients undergoing repair of a ruptured AAA. Results None of the negative control individuals were positive in any applied method. In contrast, all the participants of the positive control group were found positive in all the applied methods. No HIT was detected in 10 patients, seven of whom were pregnant at different gestational ages. The remaining 43 thrombocytopenic patients were positive in HIPA and 39 of them were also positive in the platelet microparticle assay. Out of these 39 patients, only 16 were positive in the ELISA assay. Orgaran® use in intensive care unit patients with heparin- induced thrombocytopenia and acute renal failure H Magnani1, J Wester2 1NV Organon, Oss, The Netherlands; 2Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands Critical Care 2007, 11(Suppl 2):P371 (doi: 10.1186/cc5531) Methods We retrospectively reviewed all laboratory tests for heparin antibodies requested from the ICU for the period of January–November 2006. The blood sample analysis was performed with ELISA (Asserachrom® HPIA; Diagnostica Stago, Asnieres, France). All patients were receiving fractioned heparin subcutaneously for prophylaxis when indicated. Flushes of unfractioned heparin for catheter clotting prevention were given to all patients. Only ‘positive’ results were considered positive, whilst ‘mildly positive’ and ‘uncertain’ results were considered negative. Introduction Orgaran® (danaparoid sodium) is a low-molecular- weight, nonheparin glycosaminoglycan antithrombotic that is currently a first-line treatment for heparin-induced thrombocyto- penia (HIT). This study reports on the safety of Orgaran® in ICU patients suffering from HIT and acute renal failure requiring continuous renal replacement therapy (haemofiltration). Methods Data on 96 case reports from personal experience and publications have been collated. Results During that period 300 patients were admitted (mean duration of stay 15 ± 16 days, 25th–75th 4–22 days) to the ICU; 212 (70%) were survivors and 88 (30%) were nonsurvivors. All patients presenting with thrombocytopenia (platelets < 150,000/dl) or showing a decrease >50% of their admission day’s platelet count were checked for heparin antibodies. Fifty-two samples retrieved from 48 patients suspicious for HIT were sent for heparin antibody analysis. Of the 48 patients checked, 15 (31%) were positive and 33 (68%) negative. Three of the suspected patients Results Nineteen females and 59 males (18 unknown gender) with a median age of 60 years (range 22–95 years) presented with a variety of clinical problems that either preceded or complicated their HIT; for example, postoperative/accidental trauma or overt bleeding in 61, sepsis/septicaemia/septic shock in 37, thrombo- embolism in 23, multiple organ dysfunction syndrome in 14, disseminated intravascular coagulation in eight and other miscel- laneous serious problems in 38. S149 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin P373 P373 M Kounavi, C Kroupis, E Iliopoulou, D Karamichaleli, M Katafigioti, D Degiannis, E Melissari Onassis Cardiac Center, Athens, Greece Critical Care 2007, 11(Suppl 2):P373 (doi: 10.1186/cc5533) Methods A before-and-after, observational, single-centre study. Subjects were 211 consecutive patients undergoing open repair of a ruptured AAA between 1998 and 2006. Primary outcome was development of ALI (PaO2/FiO2 < 300 and bilateral pulmonary infiltrates on chest X-ray) in the first 6 hours after surgery. Secondary outcomes were time to extubation, and survival at 30 days. Chest X-rays were examined independently by two radiologists who were blinded to the study hypothesis. Introduction Heparin-induced thrombocytopenia (HIT) type II is a serious side effect of unfractionated heparin, and to a lesser extent of low molecular weight heparins. It is mediated through an immunological mechanism and leads to platelet aggregation. The occurrence of HIT varies between 1% and 5% of patients receiving heparin while a substantial fraction of them develops thrombosis (HITT). Therefore, the rapid and accurate confirmation of HIT is a necessity. The laboratory assays available for the diagnosis of HIT are based on the detection of HIT antibodies or on the consequences of platelet activation (functional methods). Results One hundred and twenty-nine patients were operated on before and 82 after the change in FFP procurement. Groups were well matched, with respect to age, sex, co-morbidities and severity of illness, and received similar volumes of i.v. fluids and blood products from admission to 6 hours postoperatively (mean units of FFP, 8.6 before and 8.39 after, P = 0.833). The maximum tidal volume, PEEP, and CVP were similar in both groups. Norepinephrine was given to 8.5% of patients in the before group compared with 24.4% after (P = 0.001), otherwise inotrope use was similar. Primary outcome: there was significantly less ALI following the change to male-only FFP (36% before vs 21% after, P = 0.042). Secondary outcomes were not statistically different between groups; however, patients with ALI in either group had a poorer 30-day survival (59% vs 80%, P = 0.005). The purpose of the present study was to improve HIT recognition by the combination of functional and antibody determination assays. Patients and methods Fifty-three patients who presented thrombocytopenia while receiving UFH or LMWH participated in the study. A positive control group consisting of 15 patients known to suffer from HIT/HITT was used. Moreover, 19 healthy donors never exposed to heparin also participated as negative controls. P374 suffered from pulmonary embolism and were treated with therapeutic doses of i.v. unfractioned heparin; one of them was positive for heparin antibodies. The effect of male-donor-only fresh frozen plasma on the incidence of acute lung injury following ruptured abdominal aortic aneurysm repair Conclusions Our findings of high incidence of positive heparin antibodies may be mainly due to unfractioned heparin flushes. The use of heparin flushes with the new high-quality catheters and monitoring kit is questionable. Since low doses of unfractioned heparin could lead to the production of antibodies and subsequently to HIT, further studies should examine the risk-to-benefit ratio of the use of unfractioned heparin flushes in the ICU setting. S Wright, S Athey, A Leaver, C Snowden, D Roberts, J Clarkson, C Chapman, J Wallis Freeman Hospital and National Blood Service, Newcastle upon Tyne, UK Critical Care 2007, 11(Suppl 2):P374 (doi: 10.1186/cc5534) S Wright, S Athey, A Leaver, C Snowden, D Roberts, J Clarkson, C Chapman, J Wallis Freeman Hospital and National Blood Service, Newcastle upon Tyne, UK Critical Care 2007, 11(Suppl 2):P374 (doi: 10.1186/cc5534) Introduction Transfusion-related acute lung injury, due to plasma from female donors containing antileucocyte antibodies, may be a common contributor to the development of acute lung injury (ALI) in the critically ill. In July 2003 the English Blood Service stopped using female donor plasma for the manufacture of fresh frozen plasma (FFP). Patients undergoing repair of ruptured abdominal aortic aneurysm (AAA) receive large amounts of FFP and often develop ALI. We investigated whether the change to male-only FFP was associated with a change in incidence of ALI in patients undergoing emergency AAA repair. P373 The beneficial effects of the combined methods in investigating heparin-induced thrombocytopenia M Kounavi, C Kroupis, E Iliopoulou, D Karamichaleli, M Katafigioti, D Degiannis, E Melissari Onassis Cardiac Center, Athens, Greece Critical Care 2007, 11(Suppl 2):P373 (doi: 10.1186/cc5533) P376 Octaplex in routine clinical use for prophylaxis and therapy of bleeding in patients with prothrombin complex factor deficiency Methods The objective of this prospective, open-label study was to demonstrate that Octaplex, when individually dosed, efficiently corrects the INR within 1 hour post infusion. Sixty patients were included, 56 of them evaluable in terms of efficacy. T Franken1, W Rees2, N Hübner2, J Albers3, B Gansera4, M Uhl5, C Niessner6, B Sedemund-Adip7, T Tödter8 1Octapharma GmbH, Langenfeld, Germany; 2Schüchtermannklinik, Bad Rothenfelde, Germany; 3Klinikum der Joh Gutenberg Universität, Mainz, Germany; 4Städt Krankenhaus München-Bogenhausen, München, Germany; 5Klinikum Starnberg, Germany; 6Diakonissen Krankenhaus, Karlsruhe, Germany; 7Universitätsklinikum Lübeck, Germany; 8Albertinen-Krankenhaus, Hamburg, Germany Critical Care 2007, 11(Suppl 2):P376 (doi: 10.1186/cc5536) Results The median total dose was 41.1 IU/kg body weight (range 15.3–83.3 IU/kg body weight). In total the mean infusion rate was 6.42 ml/minute for the first infusion. In about one-third of the patients an average infusion rate of ≥8 ml/minute was used. The median INR decreased from 2.8 (1.5–9.5) to 1.1 (1.0–1.9) after 10 minutes and remained at that level at measurements 30 and 60 minutes after infusion. There was a rapid increase in coagulation factor activity within the first 10 minutes as well. This activity remained stably elevated for at least 4–6 hours, confirming the INR results. Of 56 patients evaluable for efficacy, for 51 (91%) the geometric mean of postinfusion values was equal to or less than the predetermined target INR. Overall haemostatic efficacy was assessed as ‘excellent’ by investigators in all 56 patients. Three of the 60 patients had minor adverse drug reactions possibly related to Octaplex. No evidence of thrombotic side effects was observed. Conclusions Octaplex corrects quickly, effectively and safely the INR to a predetermined level in patients with vitamin K antagonist- related deficiency of prothrombin complex coagulation factors. Introduction Octaplex is a new prothrombin complex concentrate that is indicated for treatment or perioperative prophylaxis of bleeding in patients with deficiency of the prothrombin complex coagulation factors, such as deficiency caused by treatment with vitamin K antagonists or by liver failure, when rapid correction of bleeding is required. The study was conducted to demonstrate both prevention of bleeding and achievement of haemostasis in acute bleeding and to obtain further information about the safety of administration of Octaplex. Methods One hundred and one patients were included in this observational study with determination of the INR as part of routine clinical management. P375 A biochemical comparison of Octaplas with a universally applicable development product (Uniplas) and single- donor fresh-frozen plasmas subjected to methylene-blue dye and white-light treatment Conclusions In comparison with the HIT-positive control group it was found that: a 92% agreement existed between the HIPA and the platelet microparticle assays; and the positive results in the ELISA were significantly lower than in the functional methods, indicating perhaps a lower sensitivity (41% agreement with the flow cytometric method and 32% with the HIPA). Therefore, the combination of functional and antibody detection assays is a necessity for the HIT recognition since both could give pseudo- positive or pseudo-negative results. A Heger, J Römisch, T Svae Octapharma PPGmbH, Vienna, Austria Critical Care 2007, 11(Suppl 2):P375 (doi: 10.1186/cc5535) A Heger, J Römisch, T Svae Octapharma PPGmbH, Vienna, Austria Critical Care 2007, 11(Suppl 2):P375 (doi: 10.1186/cc5535) Introduction The aim of this study was to perform an extensive biochemical comparison of the pharmaceutically licensed coagulation active plasma Octaplas with an identical, but universally applicable, development product (Uniplas) and single- donor fresh-frozen plasma (FFP) units subjected to a medical device treatment using a combination of methylene-blue dye and subsequent white-light exposure (MB plasma). S150 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 investigators evaluated the overall efficacy of Octaplex in 84.2% of cases as ‘very good’ and in 14.9% of cases as ‘moderate’. No adverse drug reactions or interactions were reported. Conclusions Octaplex is effective in perioperative prophylaxis of bleeding in patients with a coagulation deficit caused by treatment with vitamin K antagonists. Octaplex is also effective in treatment of acute bleeding. Octaplex was well tolerated, with no adverse reactions being reported during the study. Methods Twenty-four batches of Octaplas of different blood groups and different plasma sources, three batches of Uniplas (both products manufactured by Octapharma PPGmbH, Vienna, Austria) and 20 random commercially available bags of MB plasma of different blood groups were analysed. Beyond the global coagulation parameters, the activities of coagulation factors and protease inhibitors, as well as plasminogen, activated factor VII, plasma turbidity and lipid components, were quantified. investigators evaluated the overall efficacy of Octaplex in 84.2% of cases as ‘very good’ and in 14.9% of cases as ‘moderate’. No adverse drug reactions or interactions were reported. Conclusions Octaplex is effective in perioperative prophylaxis of bleeding in patients with a coagulation deficit caused by treatment with vitamin K antagonists. P375 Octaplex is also effective in treatment of acute bleeding. Octaplex was well tolerated, with no adverse reactions being reported during the study. Results Similar to Octaplas, Uniplas showed standardised levels of coagulation factors, plasminogen and protease inhibitors (decreased protein S and antiplasmin activities) according to the product specifications. MB plasma revealed fibrinogen levels close to or below the physiological range (<1.5 mg/ml). Coagulation factor activities in single MB plasma units both below and above the normal ranges for FFP were found in this study, reflecting the considerable variability of clinically important plasma proteins. Moreover, MB plasma revealed a higher turbidity after thawing, probably due to the elevated lipid parameters. P376 The endpoint of this study was perioperative prophylaxis of bleeding or successful treatment of acute bleeding according to clinical signs. P377 Reversal of oral anticoagulation with prothrombin complex concentrate (Octaplex) H Riess1, A Meier-Hellmann2, J Motsch3, M Elias4, F Kursten5, C Dempfle6 1Charité-Universitätsmedizin Berlin, Germany; 2HELIOS Klinikum Erfurt GmbH, Erfurt, Germany; 3Universitätsklinikum Heidelberg, Germany; 4HaEmek Medical Center, Afula, Israel; 5Octapharma Pharmazeutika Produktions ges.m.b.H., Wien, Austria; 6Universitätsklinikum Mannheim, Germany Critical Care 2007, 11(Suppl 2):P377 (doi: 10.1186/cc5537) Conclusion This study showed that there are significant differences in the biochemical characteristics between Octaplas and MB plasma, while Uniplas revealed the same high quality as Octaplas. The variability of several plasma proteins in the 20 individual MB plasma units tested was high compared with Octaplas/Uniplas. For plasma prescribers and physicians it is also important to consider the significant loss of functional fibrinogen in MB plasma when planning and monitoring the treatment of severely ill patients. Introduction Oral anticoagulant therapy with vitamin K antagonists may need to be rapidly reversed if acute bleeding occurs or surgical intervention is required. This can most effectively be achieved by administering prothrombin complex concentrates (PCCs), which correct the INR more quickly than fresh frozen plasma without the problem of volume overload. Octaplex, a virus-inactivated PCC con- taining balanced potencies of coagulation factors and the regulating proteins C and S, was developed with the intention of making a rapid contribution to coagulation whilst limiting the risk of thrombosis. Methods The objective of this prospective, open-label study was to demonstrate that Octaplex, when individually dosed, efficiently corrects the INR within 1 hour post infusion. Sixty patients were included, 56 of them evaluable in terms of efficacy. P378 vein thrombosis and spinal cord infarction. Of these two, one died secondary to coagulopathic complications post initiation of warfarin therapy 2 weeks post surgery. vein thrombosis and spinal cord infarction. Of these two, one died secondary to coagulopathic complications post initiation of warfarin therapy 2 weeks post surgery. Conclusion Our results support the evidence that recombinant factor VII is an effective haemostatic agent that can be used in patients with uncontrolled bleeding in postcardiopulmonary bypass surgery. Despite its high cost, there is an advantage in terms of effectiveness to support its use. However, its potential thrombo- embolic risk remains a concern and current evidence may restrict its use only as a rescue therapy following failed conventional treatment. Results Indications for administration of the rFVIIa were considered when there was a postsurgical bleeding (exceeding 400 ml/hour) in the absence of surgical sources of the bleeding and lack of efficacy of the conventional hemostatic procedures. After administration of the first median dose (14.45–81.35 µg/kg) rFVIIa bleeding stopped in 11 patients. A marked decrease occurred in seven patients during 2 hours. The average blood lost within 12 hours before treatment was 2,510 ml and the average blood lost within 12 hours after treatment was 1,057 ml. The average dynamic of bleeding before treatment was 1,057 ml/hour and 87.90 ml/hour after treatment. The reduction in transfusion requirements was statistically significant. Conclusion Our results support the evidence that recombinant factor VII is an effective haemostatic agent that can be used in patients with uncontrolled bleeding in postcardiopulmonary bypass surgery. Despite its high cost, there is an advantage in terms of effectiveness to support its use. However, its potential thrombo- embolic risk remains a concern and current evidence may restrict its use only as a rescue therapy following failed conventional treatment. A Kogan1, E Sharoni2, A Stamler2, M Stein2, B Medalion2, B Vidne2, E Raanani1 1Sheba Medical Center, Ramat Gan, Israel; 2Rabin Medical Center, Petah Tiqwa, Israel Critical Care 2007, 11(Suppl 2):P380 (doi: 10.1186/cc5540) A Kogan1, E Sharoni2, A Stamler2, M Stein2, B Medalion2, B Vidne2, E Raanani1 1Sheba Medical Center, Ramat Gan, Israel; 2Rabin Medical Center, Petah Tiqwa, Israel Critical Care 2007, 11(Suppl 2):P380 (doi: 10.1186/cc5540) P378 Experience of NovoSeven administration in the management of severe haemorrhage following cardiac surgery of nonhaemophilic patients Results The total dose administered per patient varied from 5.6 to 63.5 IU/kg bodyweight with a median dose of 20.4 IU/kg bodyweight. The median infusion rate was 3 ml/minute; in some cases up to 10 ml/minute were administered without any adverse reactions. The administration of Octaplex reduced the INR on average from 2.3 to 1.5. Infusion of 25 IU Octaplex per kg body weight resulted in an average decrease of about 1.2 in INR. A subgroup analysis of those patients with a postinfusion measurement within 1 hour after application of Octaplex showed a fast onset of action. The G Michalska, R Stanek Clinical Hospital, Szczecin-Police, Poland Critical Care 2007, 11(Suppl 2):P378 (doi: 10.1186/cc5538) G Michalska, R Stanek Clinical Hospital, Szczecin-Police, Poland Critical Care 2007, 11(Suppl 2):P378 (doi: 10.1186/cc5538) S151 Introduction Severe bleeding in cardiac surgery is often difficult to manage. The aim of this study is clinical evaluation of efficacy of Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Figure 1 (abstract P379) Mean hourly drain output 6 hours pre and 2 hours post NovoSeven administration. Figure 1 (abstract P379) rFVIIa in the treatment of bleeding during and after cardiac surgery. Patients and methods rFVIIa (NovoSeven; NovoNordisk, Bagsvaerd Denmark) was used in 20 adult patients aged between 41 and 74 years, average BMI 25.48 ± 4.03, who underwent open heart surgery (five coronary artery bypass surgery, two valvular surgery, four double valve operations, five combining operations (coronary artery bypass with valve repair) and four surgery for aortic aneurisms) in 2004–2006. All patients had normal coagulation parameters before surgery. We used questionnaires for indications and effectiveness of treatment. We compared the amount of blood lost within 12 hours before and within 12 hours after giving rFVIIa, the dynamics of bleeding (assessed in ml/hour) before and after treatment. We also compared the haemoglobin level, haematocrit, number of platelets and laboratory coagulation profile parameters before treatment, 2 hours and 12 hours after treatment. NovoSeven was administered 5–49 minutes after neutralization of heparin with protamin sulfate. The dosage of rFVIIa was 39.23 ± 20.70 µg/kg (range 14.45–81.35). We used Student’s t test for statistical analysis the laboratory data prior to and after rFVIIa. Mean hourly drain output 6 hours pre and 2 hours post NovoSeven administration. Factor VII for intractable bleeding after cardiac surgery Conclusions NovoSeven produces a potent haemostatic effect in bleeding events refractory to the conventional therapy complicating the cardiosurgical interventions, and substantially decreases the demand for blood transfusion. The influence of severe preeclampsia on maternal cerebral perfusion E Shifman, A Ivshin, E Gumenuk Republican Perinatal Center, Petrozavodsk, Russian Federation Critical Care 2007, 11(Suppl 2):P382 (doi: 10.1186/cc5542) M Liebl, F Masud, F Bostan, E Chi, S Pass, K Stuebing The Methodist Hospital, Houston, TX, USA Critical Care 2007, 11(Suppl 2):P381 (doi: 10.1186/cc5541) Introduction The method of transcranial color scan can be used to improve and to simplify cerebral blood flow investigations. Combi- nation of digital wide-range neurosonography and transcranial energetic Doppler scan provides a possibility of effective monitoring of cerebral blood flow. The goal of this study was to analyze cerebral flow disturbances in pregnant patients with preeclampsia. Methods Eighty-eight patients with severe preeclampsia, age 17–32 years (mean age 26 ± 4.6 years), and 90 patients with normal pregnancy, third trimester, without significant co-morbid states, age 19–34 years (mean age 25.9 ± 4.2 years), were included in the study. Patients with the following features were excluded from both groups: potentially haemodynamically signifi- cant stenosis or occlusion of magistral arteries of the head and basilar region; clinical features of congestive heart failure; arrhyth- mia. All patients underwent duplex scan of extracranial portions of brachiocephalic arteries with a linear probe and transcranial duplex scan (TCDS) in the area of the middle cerebral artery (MCA). By the transtemporal approach in the MCA M1 segment we determined the peak systolic flow velocity (Vps), maximal end- diastolic velocity (Ved), time-adjusted maximal velocity (TAMX), resistance index (RI), pulsative index (PI), and systolic/diastolic ratio (S/D). Significance of mean values differences in groups was estimated using Student t criteria. This study describes patient characteristics, recombinant activated factor VII (RF7a) dosing and clinical outcomes of cardiovascular surgery patients treated with RF7a for intractable bleeding. Use of RF7a for postsurgical bleeding, trauma or other uses in non- hemophiliac patients is considered off-label in the USA. Compre- hensive studies evaluating RF7a in cardiac surgery patients are limited. Published reports cite success with RF7a administration in massive intractable bleeding. However, patient selection, dosing, efficacy, safety and pharmacoeconomic benefit remain undefined. Patients receiving RF7a between January 2004 and September 2005 were identified via pharmacy records. Clinical databases and electronic medical records were reviewed, collecting data elements needed to assess study objectives. One hundred and twenty patients were identified. Twenty-seven patients were excluded because they lacked documentation of RF7a admini- stration, were treated for neurologic indications or had incomplete medical record data. Ninety-three patients were analyzed. Evaluation of the role of recombinant activated factor VII (NovoSeven) as a rescue haemostatic therapy in postcardiopulmonary bypass surgical patients Seven of 22 patients survived and were discharged from the hospital surgical re-exploration and other potential related adverse events (stroke, AMI, VTE, etc.) are forthcoming. Our study, like others evaluating RF7a for this indication, are limited by the retrospective scope. Randomized trials comparing RF7a doses are under way. Although RF7a therapy is costly, minimal reductions in surgical re- exploration may offset the cost of RF7a therapy provided that adverse events are not increased. Conclusion rFVIIa is effective in promoting hemostasis after cardiac surgery. rFVIIa should be considered as a possible treatment option in intractable bleeding treatment. Evaluation of the role of recombinant activated factor VII (NovoSeven) as a rescue haemostatic therapy in postcardiopulmonary bypass surgical patients Introduction Recombinant activated factor VII (rFVIIa) (NovoSeven®; Novo Nordisk, Denmark) was developed primarily for the treatment of bleeding episodes in hemophilic patients. Little information is available on the use of rFVIIa in other situations, such as intractable postsurgical or post-traumatic bleeding. In the field of cardiac surgery, only a very few cases of treatment with rFVIIa are described. Because of the difficulty in performing randomized trials in this setting, information based on case studies is very valuable Z Chen1, V Rasiah1, A Dewhurst2 1St George’s Hospital NHS Trust, London, UK; 2St Georges Hospital, London, UK Critical Care 2007, 11(Suppl 2):P379 (doi: 10.1186/cc5539) Objective Evaluation of the safety and efficacy of recombinant activated factor VII (NovoSeven) when used as a rescue haemostatic agent in refractory bleeding post bypass surgery. Methods We studied 22 consecutive patients treated with rFVIIa due to refractory postoperative bleeding. rFVIIa was given only after all other options, including revision, to stop bleeding was failed. The amount of bleeding, the number of transfused units of red cells, platelets and other blood products were recorded both before and after administration of rFVIIa. Methods A retrospective cohort study of all postcardiopulmonary bypass patients with uncontrolled bleeding despite conventional treatment (platelets, fresh frozen plasma, cryoprecipitate, and Aprotonin) who received recombinant factor VII as a rescue therapy over 12 months in a cardiothoracic centre. Results Eight patients received NovoSeven (90 µg/kg). Seven achieved significant reduction in blood loss. The mean blood loss via thoracic drains 6 hours before and 2 hours after NovoSeven administration were 341 ml/hour vs 117 ml/hour (P = 0.01) (Figure 1). On average, 5.3 units/patient packed red blood cells, 2 pools/ patient platelets, 19 ml/kg/patient fresh frozen plasma and 148 ml/ patient cryoprecipitate were used prior to NovoSeven administration. Five patients required further blood transfusion with a mean of 2.2 units/patient over the next 12 hours. Two of the eight patients developed thromboembolic complications including portal Table 1 (abstract P380) Treatment Before After Bleeding (ml/hour) 350 135 RBC 7.8 ± 2.3 1.5 ± 1.4 FFP 8.5 ± 2.4 2.5 ± 2.4 Platelets 14.5 ± 6.2 2.4 ± 2.1 Cryo 5.1 ± 1.4 0 S152 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Results See Table 1. In all patients, bleeding was decreased significantly. Seven of 22 patients survived and were discharged from the hospital Results See Table 1. In all patients, bleeding was decreased significantly. Recombinant activated factor VII treatment of severe bleeding in cardiac surgery patients: a retrospective analysis of dosing, and efficacy and safety outcomes Recombinant activated factor VII treatment of severe bleeding in cardiac surgery patients: a retrospective analysis of dosing, and efficacy and safety outcomes The influence of severe preeclampsia on maternal cerebral perfusion P382 Recombinant activated factor VII treatment of severe bleeding in cardiac surgery patients: a retrospective analysis of dosing, and efficacy and safety outcomes M Liebl, F Masud, F Bostan, E Chi, S Pass, K Stuebing The Methodist Hospital, Houston, TX, USA Critical Care 2007, 11(Suppl 2):P381 (doi: 10.1186/cc5541) Figure 1 (abstract P381) g Figure 2 (abstract P381) Figure 2 (abstract P381) The influence of severe preeclampsia on maternal cerebral perfusion RF7a effectively achieves hemostasis in patients with intractable bleeding, reducing blood product transfusions within 6 hours of treatment (Figure 1). Our findings suggest differences in PRBC transfusion reduction between RF7a doses. We observed no additional reduction PRBC transfusions in patients administered doses greater than 60–90 µg/kg (Figure 2). Effects of RF7a on Results All haemodynamic values in preeclamptic patients were decreased in comparison with the same values in healthy pregnant women: PI (mean 0.71 vs 0.84, P < 0.0001); RI (mean 0.49 vs 0.54, P < 0.0001); Vps (mean 72.8 vs 104.8 cm/s, P < 0.0001); Ved (mean 34.7 vs 48.7 cm/s, P < 0.0001); TAMX (mean 48.5 vs 67.5 cm/s, P < 0.0001); S/D (mean 1.94 vs 2.05, P < 0.001). These pathophysiological changes of cerebral haemodynamics were consistent with the Dopplerographic pattern of diminished perfusion and are typical for vascular segments, which are located proximally to the zone of abnormally high haemodynamic resistance. Conclusion The results of the performed study showed that patients with severe preeclampsia had decreased cerebral perfusion and TCDS is an effective method for estimation of preeclampsia severity. Stroke and pregnancy: etiology, timing and outcome Stroke and pregnancy: etiology, timing and outcome R Souissi, W Trabelsi, Z Haddad, M Boubaker, M Lamourou, K Baccar, C Kaddour, L Skandrani National Institute of Neurology, Tunis, Tunisia Critical Care 2007, 11(Suppl 2):P384 (doi: 10.1186/cc5544) Patients and methods Prospective data collection as part of the APRiMO study (Assessment of Prognosis and Risk of Mortality in Obstetrics). Included were all obstetric patients transferred from a referral center for high-risk pregnancies in our independent multi- disciplinary ICU. The study period was January 1996–September 2004. Demographic data, obstetric history, morbid events, length of stay (LOS), severity of illness scoring systems and organ dysfunction scores at day 1 of admission were collected. Exclusion criteria were LOS < 4 hours. The main outcome of interest was survival status at ICU discharge. Two groups were compared: patients with HELLP syndrome as defined alternatively by the two classifications (Group I), and patients without hepatic dysfunction (Group II). Results are expressed as the mean ± standard deviation. P < 0.05 was considered significant. Discrimination of the classifications was assessed by the area under the receiver operator characteristic curve (AuROC). Calibration was assessed by the Hosmer–Lemeshow (HL) goodness-of-fit test. Data were computed on SPSS 11.5, Win-XP compatible. Background and goal Most previous studies on stroke during pregnancy have mainly focused on incidence and risk factors. These studies have not reported details of etiology and stroke outcome. The present study focuses on the evaluation of the etiology, timing and outcome of stroke occurring during pregnancy. Materials and methods We conducted a retrospective analysis on all obstetric patients who have been diagnosed with stroke during pregnancy or within 8 weeks postpartum. These patients were transferred to our multidisciplinary ICU between January 1996 and December 2004. All patients were investigated with a CT scan of the brain, and MRI and/or cerebral angiography. Results Eighty-eight patients were included, 34 of them were excluded (incomplete investigations or nonstroke diagnosis: reversible leucoencephalopathy, cerebral abscess, etc.). Fifty-four patients with a diagnosis of stroke were identified: 30 patients with ischemic stroke (IS) and 24 patients with hemorrhagic stroke (HS). The majority of events (45 patients, 83%) occurred in the third trimester and postpartum period (P = 0.02). A specific cause was identified in 24 patients (80%) of IS and in 21 patients (87%) of HS. Stroke and pregnancy: etiology, timing and outcome Causes of IS include preeclampsia/eclampsia in 11 patients, venous thrombosis and coagulopathies (deficiencies of protein C, protein S, and activated protein C resistance) in nine patients, valvular heart disease with history of prior stroke in four patients and six patients had no definable cause. The major causes of HS were preeclampsia/eclampsia in eight patients, four patients presented with hemorrhage secondary to aneurysmal rupture, three patients presented with bleeding from arterio-venous malformations (AVM), bleeding as a consequence of disseminated intravascular coagulation (DIC) occurred in two patients and seven patients had hemorrhagic events of unknown origin. Hypertensive disorders of pregnancy were the most common comorbid conditions (32%). Results and discussion Differences between Group I and Group II were statistically significant concerning obstetric hemorrhagic complication (P < 0.001), incidence of acute renal failure (P = 0.01), mortality (P = 0.001), LOS (6.5 ± 7 days vs 4.4 ± 4 days, P = 0.001), SAPS-Obst score (24.5 ± 8 vs 16.8 ± 7, P < 0.001). The Mississippi classification discriminated well, but calibrated badly. In contrary, the Tennessee classification was a poor discriminator but calibrated very well. See Table 1. P383 HELLP syndrome: utility of specific classifications as prognostic tools R Souissi, Z Haddad, W Trabelsi, N Baffoun, M Boubaker, C Kaddour, L Skandrani National Institute of Neurology, Tunis, Tunisia Critical Care 2007, 11(Suppl 2):P383 (doi: 10.1186/cc5543) R Souissi, Z Haddad, W Trabelsi, N Baffoun, M Boubaker, C Kaddour, L Skandrani National Institute of Neurology, Tunis, Tunisia Critical Care 2007, 11(Suppl 2):P383 (doi: 10.1186/cc5543) S153 Introduction HELLP syndrome is a specific complication of pregnancy characterized by hemolysis, elevated liver enzymes and ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Table 1 (abstract P383) Number of patients, discrimination and calibration statistic tests for each classification Classification Dead Alive Tennessee n = 45 (20.3%) n = 177 Mississippi n = 20 (26.7%) n = 55 ROC HL Tennessee 0.75 0.001 Mississippi 0.64 0.533 Number of patients, discrimination and calibration statistic tests for each classification Nineteen deaths (35%) occurred in our study, eight patients with infarction and 11 patients with hemorrhage. Thirty-one patients left the hospital with neurologic deficits, requiring chronic care or rehabilitation. Discussion and conclusion The results of the present study complement the findings of previous studies on timing of stroke in pregnancy [1,2]. We found that preeclampsia/eclampsia and intracranial vascular malformations were the major causes of stroke in pregnancy, which agrees with other findings [2,3]. Our study shows a high mortality rate of 35%, which indicates that careful management of at-risk patients during the first postpartum weeks is warranted. Conclusion Both models classified patients according to different criteria but were correlated with mortality. None of the classifications discriminated and calibrated well at the same time. The two models seem to be complimentary. Development of an aggregate classification could refine the models. classifications discriminated and calibrated well at the same time. The two models seem to be complimentary. Development of an aggregate classification could refine the models. 1. Audibert F, Friedman SA, Frangieh AY, Sibai BM: Clinical utility of strict diagnostic criteria for the HELLP syndrome. Am J Obstet Gynecol 1996, 175:460-464. P384 low platelet count. Maternal mortality was reported to be as high as 24%. Two classifications of the HELLP syndrome are widely used (Tennessee [1] and Mississippi [2]). The aim of this study is to determine mortality of HELLP syndrome as defined by each classification and try assessing the most relevant. Fractional excretion of urea in the follow-up of acute renal failure due to prerenal azotemia Fractional excretion of urea in the follow-up of acute renal failure due to prerenal azotemia Results Six hundred and forty patients were reviewed (mortality rate 13.3%). ARF was diagnosed in 223 patients. Main risk factors present at admission were: acute circulatory failure, transfusion and association with haemolysis elevated liver enzyme and low platelet count (HELLP) syndrome. ARF patients with HELLP syndrome on admission were most likely to develop and alter multiple organ dysfunctions/failures. ARF is associated with an elevated relative risk of mortality (x1.5). Anuria and a serum creatinine level > 300 µmol/l were independent risk factors for mortality (OR 2 and 7, respectively). The ICU mortality of ARF patients increased with the number of failing organs on admission, especially persistent circulatory failure over time. The LOD score is at least as good as the SOFA score in evaluating the association MOF–ARF with mortality. In fact, LOD cutoff values defining cardiovascular, respiratory hepatic and hematologic organ failures fit particularly our obstetric population. S Kuster, C Giambarba, A Kneubühl, G Keusch Stadtspital Waid, Zürich, Switzerland Critical Care 2007, 11(Suppl 2):P387 (doi: 10.1186/cc5547) Fractional excretion of urea (FEU) is a major issue to discriminate between prerenal azotemia and acute tubular necrosis in acute renal failure (ARF). Its role in the course of ARF remains unclear. The aim of this study was to evaluate FEU in the follow-up of ARF due to prerenal azotemia in order to predict the necessity of renal replacement therapy (RRT). The prospective study took place at the ICU of Stadtspital Waid, Zürich. All patients admitted starting from 19 February 2006 were evaluated for ARF according to the RIFLE classification. ARF due to prerenal azotemia was defined as ARF combined with FEU of less than or equal to 35%. FEU was calculated as [(urine urea/blood urea)/(urine creatinine/plasma creatinine)] x 100. Urine specimens were taken and FEU was calculated daily until complete or partial renal recovery was reached or the criteria for RRT were met. The goal of therapy was reconstitution of renal function by treatment of the underlying condition. RRT was initiated according to the usual criteria. Statistics were determined using Fisher’s exact test. Conclusions Most important risk factors for ARF or mortality are often present on admission. Reference 1. Bellomo et al.: Crit Care 2004, 8:R204–R212. 1. Bellomo et al.: Crit Care 2004, 8:R204–R212. Figure 1 (abstract P387) Fractional excretion of urea (FEU) in the follow-up of acute renal failure (ARF) due to prerenal azotemia. Data presented as mean ± SD. n = number of patients. Figure 1 (abstract P387) Acute renal failure in obstetrics: risk factors and outcome Methods A retrospective observational study was performed in a general ICU at a Swedish university hospital. All adult patients treated at the ICU during 2004–2006 were included. Reduced kidney function was defined as ≤80 ml/min/1.73 m2. Z Haddad1, C Kaddour2, R Souissi2, T Chaaoua2, M Laamourou2, I Pipien1, S Nagi2 1CHI St-Cloud, France; 2National Institute of Neurology, Tunis, Tunisia Critical Care 2007, 11(Suppl 2):P385 (doi: 10.1186/cc5545) Results GFR markers are frequently ordered in the ICU. The majority of the patients had a reduced kidney function as evaluated by Cystatin C and/or p-creatinine. A total 92.1% of the patient test results had Cystatin C estimated GFR (eGFR) ≤80 ml/min/1.73 m2, 75.3% had eGFR ≤50 ml/min/1.73 m2 and 30.4% had eGFR ≤20 ml/min/1.73 m2. In contrast, only 46% of the patients had reduced renal function assessed by plasma creatinine. Introduction Acute renal failure (ARF) was newly recognized as a specific mortality risk factor [1] and is in general associated with a high mortality rate. Introduction Acute renal failure (ARF) was newly recognized as a specific mortality risk factor [1] and is in general associated with a high mortality rate. Hypothesis Identifying risk factors for ARF could help reduce mortality. We shall try to describe them in critically ill obstetric patients, and explain ARF association with multiple organ failure (MOF) and outcome using the Sequential Organ Failure Assessment (SOFA) score and Logistic Organ Dysfunction (LOD) score. y p Conclusions The GFR is commonly assessed in the ICU. Cystatin C is a more sensitive GFR marker than creatinine. A majority of the ICU patients had a reduced GFR. Many of the pharmaceuticals used in the ICU are cleared by the glomeruli. It is thus important to monitor kidney function regularly, using an adequate assay. When possible, drugs with a plasma concentration that is less influenced by the GFR should be used. Methods An open prospective observational cohort study in a multidisciplinary ICU. All critically ill obstetric patients were analysed unless diagnosed with chronic renal failure or kidney transplant. ARF was defined as serum creatinine ≥100 µmol/l and/or urine output ≤500 ml/day and/or doubling of baseline serum creatinine levels. Fractional excretion of urea in the follow-up of acute renal failure due to prerenal azotemia During the ICU stay, other organ failures (especially cardiovascular) are important risk factors to develop or alter renal function, especially persistence of circulatory shock; thus, aggressive fluid challenge and volume infusion policy could help ARF prevention. HELLP syndrome and ARF is a particularly morbid association because of accumulating organ failures. Reference P385 P385 using the creatinine and Cystatin C estimated GFRs as several pharmaceuticals are prescribed according to renal function. using the creatinine and Cystatin C estimated GFRs as several pharmaceuticals are prescribed according to renal function. References 1. Sharshar T, Lamy C, Mas JL: Incidence and causes of strokes associated with pregnancy and puerperium. A study in public hospitals of Ile de France. Stroke in Preg- nancy Study Group. Stroke 1995, 26:930-936. 1. Sharshar T, Lamy C, Mas JL: Incidence and causes of strokes associated with pregnancy and puerperium. A study in public hospitals of Ile de France. Stroke in Preg- nancy Study Group. Stroke 1995, 26:930-936. 2. Martin JN Jr, Magann EF, Blake PG, et al.: Analysis of 454 pregnancies with severe preeclampsia/eclampsia HELLP syndrome using the 3-class system of classification. Am J Obstet Gynecol 1993, 68:386. 2. Kittner SJ, Stern BJ, Feeser BR, Hebel R, Nagey DA, Buch- holz DW, Earley CJ, Johnson CJ, Macko RF, Sloan MA, Wityk RJ, Wozniak MA: Pregnancy and the risk of stroke. N Engl J Med 1996, 335:768-774. 3. Jaigobin C, Silver FL: Stroke and pregnancy. Stroke 2000, 31:2948-2951 S154 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Hemodynamic goal-directed intermittent hemodialysis S Jog, P Akole, N Gogate, S Gadgil Deenanath Mangeshkar Hospital and Research Centre, Pune, India Critical Care 2007, 11(Suppl 2):P388 (doi: 10.1186/cc5548) Introduction Intermittent hemodialysis (IH) is the commonest form of renal replacement therapy (RRT) in the majority of Indian ICUs as each continuous veno-venous hemofiltration session for 24 hours costs around €250, against IH that costs around €25/4 hour session. The major concern of IH in septic shock patients is hemodynamic instability. Whether stringent hemodynamic monitor- ing and maintaining preset goals would reduce these instabilities and deliver optimal RRT is not clear. We undertook a prospective study to evaluate this concept. Results There were 168 consecutive patients (86 males). The mean age was 55 ± 19 years. The mean APACHE II score was 11 ± 8. Main reasons for ICU admission according to APACHE II classification were gastrointestinal perforation/obstruction n = 100, gastrointestinal surgery due to neoplasia n = 21, vascular surgery n = 18, gastrointestinal bleeding n = 6, hemorrhagic shock n = 5, sepsis n = 5, chronic cardiovascular disease n = 4, respiratory failure n = 3, cardiovascular n = 3, metabolic disturbance n = 2 and renal surgery due to neoplasia n = 1. The mean LOS was 5 ± 13 days. The DAKI frequency was 6.5% (n = 11). By means of univariable analysis, risk factors for DAKI were male sex, creatinine level ≥1.5 mg/dl at admission, APACHE II score ≥25, use of a pulmonary artery catheter, need for mechanical ventilation ≥48 hours, hemoglobin level ≤7 g/dl, and enteral and parenteral nutritional support. In the multivariate analysis, only APACHE II score ≥25 (OR 14.9; 95% CI 1.9–111.6, P = 0.008), use of enteral support (OR 20.3; 95% CI 3.5–117.7, P < 0.001) and use of pulmonary artery catheter (OR 10.7; 95% CI 1.3–88.5, P = 0.028) were independent predictors of DAKI. The overall postoperative mortality rate was 10.7%; it was 54% in patients with DAKI compared with 7.6% in patients without DAKI. P389 Predictive factors of dialytic acute kidney injury in patients admitted to the intensive care unit after nontraumatic emergency abdominal surgery F De Marco, M Barbosa, A Fantauzzi, C Nascimento, W Imanishi, A Guimares Hospital Vivalle, Sao Jose dos Campos, Brazil Critical Care 2007, 11(Suppl 2):P389 (doi: 10.1186/cc5549) F De Marco, M Barbosa, A Fantauzzi, C Nascimento, W Imanishi, A Guimares Hospital Vivalle, Sao Jose dos Campos, Brazil Critical Care 2007, 11(Suppl 2):P389 (doi: 10.1186/cc5549) In patients presenting with ARF due to prerenal azotemia, an increase of FEU above 35% within the first 48 hours after initiation of conservative therapy for ARF is a valuable parameter to predict renal recovery. After initiation of conservative therapy, measurement of FEU is of no value concerning discrimination of prerenal azotemia and acute tubular necrosis in ARF. Introduction Although postoperative risk factors for dialytic acute kidney injury (DAKI) are well described in a wide range of clinical settings, we have few data regarding nontraumatic emergency abdominal surgery. The aim of this study was to describe these factors in this subgroup of patients. P386 The majority of patients in a Swedish university hospital intensive care unit have reduced glomerular filtration rate measured by Cystatin C Introduction Renal dysfunction is associated with increased morbidity and mortality in intensive care patients. The aim of this study was to investigate the use of laboratory markers in an ICU, especially glomerular filtration rate (GFR) markers, and to compare two GFR markers, creatinine and Cystatin C. A secondary aim was to assess the frequency of reduced GFR in this patient group Fractional excretion of urea (FEU) in the follow-up of acute renal failure (ARF) due to prerenal azotemia. Data presented as mean ± SD. n = number of patients. S155 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Conclusion Goal-directed hemodynamic management during IH can reduce hemodynamic instability and deliver reasonably opti- mum RRT in the absence of continuous veno-venous hemofiltration facilities. By 7 December 2006, 15 patients met the inclusion criteria for ARF due to prerenal azotemia (nine males, six females). The mean age was 71 ± 11 (SD) years for male patients and 58 ± 31 years for female patients. Twelve out of the 15 patients responded to conservative management and had complete or partial renal recovery. Three patients needed RRT. Two of them refused RRT and died during the course of the disease. During the first 48 hours after initiation of conservative therapy, FEU remains less than or equal to 35% in all three patients who needed RRT. By contrast, nine out of 12 patients in whom renal function recovered without RRT showed a FEU of more than 35% within the first 48 hours (P < 0.05) (Figure 1). P388 Methods We have conducted a retrospective cohort study in order to identify independent risk factors. We reviewed data from patients admitted to the ICU after nontraumatic emergency abdominal surgery from April 2003 to October 2006. Epidemio- logical data, outcome and ICU resource utilization were recorded. Statistical analysis was performed by univariate analysis (Fisher’s exact test, chi-square test) followed by multivariate stepwise logistic regression. Hemodynamic goal-directed intermittent hemodialysis Methods Preset goals of keeping the mean arterial pressure (MAP) > 75 mm, cardiac output (CO) > 5 l/min and cardiac index (CI) > 2.5 l/min/m2 throughout the session were attempted to achieve by a stepwise protocol as follows: (1) fluid boluses, (2) increase in vasopressor/inotrope dose, (3) adjustment in the ultrafiltration rate between 250 and 700 ml/hour, and (4) adjust- ment in the blood flow rate between 150 and 300 ml/minute on a hemodialysis machine. Dopamine, norepinephrine, vasopressin and dobutamine were used alone or in combination to achieve these goals. Hemodynamic monitoring and data collection were done with Datex S-5 and Flo-Trac Vigileo monitors. Results Nineteen IH sessions of seven patients with septic shock were monitored and managed in the ICU. The baseline APACHE II score was 24.10 ± 4.98 and all patients had at least three organ failures. The average duration was 4.42 ± 1.30 hours and fluid removal was 2,000 ± 527 ml per IH session. The preIH MAP, CO and CI were 81.10 ± 10.80 mmHg, 6.23 ± 2.24 l/min and 3.45 ± 1.07 l/min/m2, respectively. The MAP, CO, CI were 81.42 ± 8.44 mmHg, 6.27 ± 2.24 l/min and 3.49 ± 1.07 l/min/m2 at 60 minutes; 79.36 ± 15.33 mmHg, 6.24 ± 2.65 l/min and 3.46 ± 1.31 l/min/m2 at 120 minutes; 82.83 ± 14.00 mmHg, 6.48 ± 2.36 l/min and 3.60 ± 1.06 l/min/m2 at 180 minutes; and 84.44 ± 13.98 mmHg, 6.46 ± 2.17 l/min and 3.6 ± 0.95 l/min/m2 at 240 minutes, respectively. Preset goals were maintained with fluids alone in four patients, fluids and escalation of vasopressor was required in seven patients, and fluids, vasopressor escalation with ultrafiltration and blood flow adjustments in six patients. Only 2/19 sessions were terminated at 120 and 90 minutes, due to development of new myocardial infarction in one and persistent hypotension in other. Conclusions DAKI following nontraumatic emergency abdominal surgery has a high mortality rate, and APACHE II score ≥25, use of enteral nutritional support and use of pulmonary artery catheter are its postoperative predictive factors. P390 Introduction Despite the use of several prophylactic approaches, contrast-induced nephropathy (CIN) remains a clinical problem. P390 Long-term outcome of patients with contrast-induced nephropathy Introduction Despite the use of several prophylactic approaches, contrast-induced nephropathy (CIN) remains a clinical problem. Introduction Despite the use of several prophylactic approaches, contrast-induced nephropathy (CIN) remains a clinical problem. S156 Available online http://ccforum.com/supplements/11/S2 Figure 1 (abstract P391) Figure 1 (abstract P391) CIN is the third leading cause of hospital-acquired renal failure. CIN is associated with several risk factors such as diabetes and hypertension as well as with prolonged hospitalization and increased mortality. Little is known about long-term renal outcome. Within the last 10 years we have performed nine controlled studies on prophylaxis of CIN with a total number of about 1,200 patients. It was the aim of this study to investigate the long-term outcome of patients with CIN within these studies. y Within the last 10 years we have performed nine controlled studies on prophylaxis of CIN with a total number of about 1,200 patients. It was the aim of this study to investigate the long-term outcome of patients with CIN within these studies. Methods This study presents the data of the first 25 patients with CIN (planned: 80 patients) including serum creatinine 1 week, 1 month, 6 months and 1 year after the contrast medium. The outcome was investigated by chart review and telephone call. Results All patients were Caucasian and had a mean age of 69.6 ± 10.6 years. Eight were female, 17 were male. Twenty-four patients had risk factors for CIN such as diabetes (8%), hyper- tension (44%) or both (28%) and preexisting renal impairment (15%) prior to contrast medium application. Their mean serum creati- nine before contrast medium application was 1.81 ± 1.21 mg/dl. The contrast procedure was coronary angiography in 18 patients and CT in seven patients. For prophylaxis of CIN, six patients received N-acetylcysteine and three patients received both N- acetylcysteine and theophylline prior to contrast medium exposition. Mean serum creatinine 48 hours after contrast medium was 2.36 ± 1.36 mg/dl (P < 0.01 vs 0 hours). The mean maximum creatinine increase was 0.64 ± 0.26 mg/dl (P < 0.01 vs 0 hours). Four patients (16%) died during the first week after contrast medium, one of them despite initiation of dialysis 2 days after contrast application. ICU than those without ARF. Patients with ARF showed higher incidence of liver dysfunction, and needed a longer mechanical ventilation and ICU stay. P391 Objective To investigate the effect of the antifibrinolytic agents aprotinin and tranexamic acid on the occurrence of acute post- operative renal dysfunction in cardiac surgery on patients treated preoperatively with angiotensin-converting enzyme (ACE) inhibitors. Survey of acute renal failure in patients after cardiovascular surgery N Iguchi, H Imanaka, M Takeuchi, T Nishida, M Ichikawa, C Takayama, S Akaeda National Cardiovascular Center, Suita, Osaka, Japan Critical Care 2007, 11(Suppl 2):P391 (doi: 10.1186/cc5551) Methods A total of 7,420 patients who had undergone nonemergency coronary artery bypass graft or valve surgery in the Bristol Royal Infirmary from January 2000 until end of March 2006 were included in a retrospective observational study. The incidence of postoperative renal dysfunction was compared in patients given aprotin, tranexamic acid or no antifibrinolytic agent, using propensity-adjusted multivariable logistic regression. Further analysis was performed comparing patients taking ACE inhibitors preoperatively with those not taking ACE inhibitors. Renal dysfunction was defined as creatinine higher than 200 µmol/l and/or renal dialysis. Patients with a previous history of renal dysfunction were excluded from the study. Introduction Acute renal failure (ARF) is one of the major complications after cardiovascular surgery. To investigate the incidence and prognosis of ARF after cardiac surgery, we performed a retrospective study. Our hypothesis is that ARF is more common in patients who underwent surgery for great vessel diseases than in those who underwent coronary or valve surgery. Methods We enrolled patients over 18 years old who underwent cardiovascular surgery and entered our ICU between 2004 and 2005. The background diseases were classified into two groups: great vessel disease, and coronary/valve disease. We determined ARF when serum creatinine increased by more than 50% of the preoperative values, or when renal replacement therapy was newly started. By reviewing ICU charts, we collected data before, on admission to the ICU and during the ICU stay. Results Using propensity-adjusted multivariable logistic regression (C-index, 0.82), the use of aprotinin in patients taking ACE inhibitors was associated with more than doubling the risk of acute postoperative renal failure in patients undergoing nonemergency cardiac surgery (odds ratio 2.64; confidence interval 1.32–5.27). Tranexamic acid was also associated with a significant increase in the risk of renal failure (odds ratio 1.59; confidence interval 1.09–2.31) in patients taking ACE inhibitors. However, in this study, there was no association between either aprotinin (odds ratio 1.01) or tranexamic acid (odds ratio 1.19) and postoperative renal failure in patients not taking ACE inhibitors. Results ARF occurred more frequently in patients with great vessel disease than in those with coronary/valve disease (33.5% vs 11.2%, P < 0.05). The prognosis of patients with ARF was poorer than those without ARF in both groups (Figure 1). P390 Conclusion ARF is common after cardiovascular surgery, especially after surgery for great vessel disease. ARF was associated with more postoperative organ disorders. P392 One year after CIN, the mean serum creatinine in the survivors was 1.85 ± 1.39 mg/dl (P = 0.48 vs 0 hours). A clinical relevant increase of >0.3 mg/dl compared with baseline creatinine was found in six (24%) patients. Antifibrinolytic agents and angiotensin-converting enzyme inhibitors: the effect on postoperative renal dysfunction in cardiac surgery R Mouton, A Binks, I Davies Bristol Royal Infirmary, Bristol, UK Critical Care 2007, 11(Suppl 2):P392 (doi: 10.1186/cc5552) R Mouton, A Binks, I Davies Bristol Royal Infirmary, Bristol, UK ( ) Conclusion CIN is a serious complication of contrast medium administration and is associated with an increased mortality and long-time morbidity. Survey of acute renal failure in patients after cardiovascular surgery Patients with ARF showed a longer operation time, larger intraoperative bleeding and a higher level of blood lactate on admission to the Conclusion In cardiac surgery, there is a significant association between use of the antifibrinolytic drugs aprotinin and tranexamic S157 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin acid and the occurrence of acute postoperative renal dysfunction, in patients taking ACE inhibitors. The potential blood-saving benefits of antifibrinolytic drugs should be weighed up against this serious postoperative complication. A comparison of Gc globulin and neutrophil gelatinase- associated lipocalin in patients with liver disease Introduction A number of preoperative patient-specific risk factors contribute to increased perioperative cardiovascular risk (myo- cardial infarction, heart failure, death) in patients undergoing major noncardiac surgery [1]. Renal impairment is one predictor. Creatinine values are a poor reflection of true renal function. Measures of the glomerular filtration rate provide a more accurate measure of renal function; as such, the true prevalence of renal impairment in this population may be significantly higher than previously appreciated. Our aim was to identify that proportion of elective vascular patients undergoing abdominal aortic surgery that have CKD, assessed by the estimated glomerular filtration rate (eGFR, ml/min/1.73 m2 body surface area; creatinine, µmol/l) [2]. A Portal, M Austin, M Bruce, E Sizer, G Auzinger, M Heneghan, J Wendon Kings College Hospital, London, UK Critical Care 2007, 11(Suppl 2):P394 (doi: 10.1186/cc5554) Kings College Hospital, London, UK Introduction Gc globulin, a hepatically synthesized actin binding protein, is known to decrease in both acute and chronic liver disease, and low levels are associated with poor prognosis. Neutrophil gelatinase-associated lipocalin (NGAL), a member of the lipocalin family of proteins, has been shown to be an early biomarker of ischaemic renal damage. We prospectively investigated the use of these proteins as markers of severity of illness and prognostication in acute and acute-on-chronic liver failure requiring intensive care. Introduction Gc globulin, a hepatically synthesized actin binding protein, is known to decrease in both acute and chronic liver disease, and low levels are associated with poor prognosis. Neutrophil gelatinase-associated lipocalin (NGAL), a member of the lipocalin family of proteins, has been shown to be an early biomarker of ischaemic renal damage. We prospectively investigated the use of these proteins as markers of severity of illness and prognostication in acute and acute-on-chronic liver failure requiring intensive care. Methods A retrospective analysis of our ‘ABC study’ database was undertaken. The ABC study is an ongoing study looking at preoperative risk assessment using cardiopulmonary exercise testing in patients undergoing elective aortic surgery. Methods NGAL and Gc globulin were measured on admission to our unit using a sandwich ELISA technique (AntibodyShop®) in 17 patients with acute liver failure (ALF) and 11 patients with acute-on- chronic liver disease (ACLD). Biochemical and physiological variables were collected prospectively and entered into a physiological database (ICARE). All measurements were taken on day 1 of admission. Results are expressed as the median and interquartile range. P393 2. K/DOQI clinical practice guidelines for chronic kidney disease: evaluation, classification, and stratification. Am J Kidney Dis 2002, 39:S1-S266. P393 Preoperative assessment of patients undergoing abdominal aortic surgery: chronic kidney disease is almost always present A Turley, S Owen, E Kothmann, M de Belder, A Parry, G Danjoux The James Cook University Hospital, Middlesbrough, UK Critical Care 2007, 11(Suppl 2):P393 (doi: 10.1186/cc5553) 3. JBS 2: Joint British Societies’ guidelines on prevention of cardiovascular disease in clinical practice. Heart 2005, 91 (Suppl 5):v1-v52. 3. JBS 2: Joint British Societies’ guidelines on prevention of cardiovascular disease in clinical practice. Heart 2005, 91 (Suppl 5):v1-v52. A Turley, S Owen, E Kothmann, M de Belder, A Parry, G Danjoux The James Cook University Hospital, Middlesbrough, UK Critical Care 2007, 11(Suppl 2):P393 (doi: 10.1186/cc5553) A comparison of Gc globulin and neutrophil gelatinase- associated lipocalin in patients with liver disease Results Sixty-six patients were included in the analysis. All patients were Caucasians, 62 males (94%). No patient had a pre-existing diagnosis of chronic renal impairment. No patients had stage 4/5 CKD (severely reduced kidney function, eGFR < 30). Moderately reduced kidney function (eGFR 30–59, CKD stage 3) was seen in 20 (30%) patients, and mildly reduced kidney function (eGFR 60–89, CKD stage 2) in 44 (67%). Only two patients had normal kidney function. The mean total cholesterol for the cohort was 4.6 mmol/l (±1 mmol/l). See Table 1. g Results Admission parameters: serum creatinine 185 µmol/l (89–266), urine output/24 hours: 340 ml (0–1,111), APACHE II score 20 (15–25), lactate 2.6 (1.8–4.68), INR 2.6 (1.6–3.8) and AST 1,404 (124–6,349). There were significant differences between median Gc globulin in ALF patients compared with ACLD: 25 mg/l (10–50) vs 50 mg/l (25–129), P = 0.036. No significant differences were seen for NGAL. Gc globulin correlated with admission creatinine (r = 0.44, P < 0.01), INR (r = 0.68, P < 0.01), and SOFA score (r = 0.419, P < 0.01) in both patient groups. These relationships persisted when admission Gc globulin was examined in regard to day 5 parameters. Admission Gc globulin correlated with D3 urine output (r = 0.619, P < 0.001). NGAL correlated with urine output throughout the first 5 days of admission (r = –0.593 on day 1, r = –0.674 on day 3, P < 0.001) and also with SOFA score. High admission NGAL was associated with requirement for renal replacement therapy on day 3 (ROC AUC 0.91 (0.895–1.022, P < 0.001)), outperforming both admission Gc globulin and admission creatinine. A low admission Gc globulin more accurately predicted the need for haemofiltration on day 5 (AUC 0.889, 0.734–1.044, P < 0.007) than either NGAL or creatinine on admission. References acid and the occurrence of acute postoperative renal dysfunction, in patients taking ACE inhibitors. The potential blood-saving benefits of antifibrinolytic drugs should be weighed up against this serious postoperative complication. 1. Eagle KA, Berger PB, Calkins H, et al.: ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac surgery – executive summary. A report of the American College of Cardiology/American Heart Associa- tion Task Force on Practice Guidelines (committee to update the 1996 guidelines on perioperative cardiovascu- lar evaluation for noncardiac surgery). Anesth Analg 2002, 94:1052-1064. Acknowledgement David Finch, Audit & Information Systems, Cardiac Services, is thanked for doing the statistical analysis. P395 Fibrinogen as a prognostic indicator in hepatic failure M Thomas, M Duffy, G Auzinger, W Bernal, E Sizer, J Wendon King’s College Hospital, London, UK Critical Care 2007, 11(Suppl 2):P395 (doi: 10.1186/cc5555) M Thomas, M Duffy, G Auzinger, W Bernal, E Sizer, J Wendon King’s College Hospital, London, UK Critical Care 2007, 11(Suppl 2):P395 (doi: 10.1186/cc5555) Of the patients not admitted to our LITU (162 to ward and 176 to IC), 79% were deemed too well to benefit and 2% due to no beds. the mean ± SD SOFA score for the too sick to benefit group (19%) was 11.5 ± 4.3 (63% had decompensated chronic liver disease (d-CLD), 36% with malignancy, major sepsis or morbid cardiocerebral event). The mean ± SD SOFA scores for the ward, IC and LITU groups were 2.5 ± 2.4, 7.9 ± 4.6 and 7.8 ± 4.5, respectively. The SOFA liver score was highest in all three triage groups, overall mean of 2.3 (ward, 1.9 ± 1.4; IC, 2.6 ± 1.2; LITU, 2.4 ± 1.2), compared with other components (respiratory 0.9, cardiovascular 0.7, coagulation 0.9, renal 1.1, central nervous system 0.8). Patients with INR > 6 were more likely to be triaged to LITU (OR 4.2). Introduction Fibrinogen as a prognostic test of mortality in acute hepatic failure has not been reported. Two hundred and sixty patients admitted to the liver intensive therapy unit (LITU) with hepatic failure (that is, subacute, acute and fulminant) between 1 January 2004 and 30 September 2006 were identified from the LITU database (I-Care, UK). Twelve patients without fibrinogen testing on admission were excluded from the analysis. Methods The mean (±SD) age was 38.1 (14) years. Ninety-seven patients were male and 151 female; 116 had taken a paracetamol overdose (POD). The mean (±SD) fibrinogen on admission was 1.88 (1.24) g/l. Overall ICU mortality was 30.2% (POD 43.4%; non-POD 26.1%). Forty-nine patients received a transplant (14 POD and 35 non-POD). A total of 97 patients were admitted to our LITU (five of 17 patients triaged at referral to our hospital liver ward); six patients died before arrival and three patients were diverted to another liver intensive care facility for family convenience. Fifteen patients underwent liver transplantation (10/49 with ALDF, 5/37 with d-CLD). Mortality in the LITU group was 36%, and highest with d-CLD (57% vs 25% with ALDF). What is the role of carboxyhaemoglobin in patients with liver failure? What is the role of carboxyhaemoglobin in patients with liver failure? M Austin, A Portal, J Wendon King’s College Hospital, London, UK Critical Care 2007, 11(Suppl 2):P397 (doi: 10.1186/cc5557) Background Patients with liver failure have haemodynamic and respiratory instability, the aetiology of which is unclear. Unregulated vasoactive mediators may have an important role in this physiological phenomenon. Carbon monoxide, a vasodilator, has been extensively studied and is easily measured using circulating carboxyhaemoglobin (COHb). The levels of circulating COHb have been reported as being elevated in patients with stable cirrhosis and hepatopulmonary syndrome. It is unknown whether the levels of COHb are elevated in patients with liver failure. P395 Mean referral, post-transfer and 48-hour SOFA scores of LITU nonsurvivors were 10.7, 12.7 and 13.9, respectively (6.5, 7.7 and 7.5 for survivors). Results Fibrinogen levels (all in g/l) in survivors were higher than in nonsurvivors (1.98 ± 1.26 vs 1.63 ± 1.15; P = 0.033). Fibrinogen was higher in survivors of POD (1.81 ± 1.0 vs 1.41 ± 0.94; P = 0.039) and not significantly different between groups in non- POD hepatic failure (2.13 ± 1.43 vs 1.85 ± 1.31; P = 0.28). Fibrino- gen was higher in those who survived after transplant (1.49 ± 0.83 vs 1.23 ± 0.23; P = 0.27). A cutoff value of fibrinogen of ≤1 g/l has sensitivity 0.47 and specificity 0.74 (positive predictive value (PPV) 0.44) for prediction of death in acute hepatic failure. In POD the sensitivity is 0.51, specificity 0.81 and PPV 0.59; in non-POD hepatic failure the values are 0.29, 0.73 and 0.31 respectively. In those POD who did not receive a transplant, fibrinogen ≤1 g/l has sensitivity 0.61, specificity 0.78 and PPV of 0.57 for death. Fibrinogen is higher in survivors of hepatic failure after POD. Conclusions The refusal rate to our LITU due to no beds was low. Paracetamol remains a common cause for drug-induced liver injury, although few are severe cases. The triage decision appeared to be influenced by the INR, d-CLD with or without a reversible cause and the presence/absence of morbid extrahepatic diagnoses. Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 0.813, P = 0.006. There were no significant differences in NGAL values between survivors and nonsurvivors for the whole group. NGAL was significantly lower in survivors than nonsurvivors in the ACLD group (AUC 0.875, P = 0.47). 15-bed LITU as recorded on a standardised proforma. Data evaluated were: referral diagnoses; reasons for refusal to LITU (‘too well to benefit’, ‘too sick to benefit’ or ‘no beds’); triaged destination of care (‘ward’ at referral hospital or our hospital liver ward, ‘IC’ at referral hospital high-dependency unit/ICU or ‘LITU’); and parameters for Sequential Organ Failure Assessment (SOFA) score. Conclusion Gc globulin and NGAL are potentially useful methods of identifying patients with a particularly poor prognosis and those needing renal replacement therapy. Further larger prospective studies are needed to elucidate their exact role not only in liver disease but also in the general ITU population. Result A total of 620 calls were received for 439 referrals (37% during the 17:00–24:00 hours period, 11% during 00:00–08:00 hours), with 38% from the London region. Drug-induced acute liver dysfunction/failure (ALDF) was the most common reason for consultation (39%), with paracetamol being most common (163/172), most of whom were triaged to a referral hospital ward (63% vs 14% to LITU). Patients with diagnosis of ‘ischaemic hepatitis’ tended to be triaged to IC (82%), and pancreatobiliary disease and trauma to the LITU (69% and 80%). P397 Conclusion Fibrinogen ≤1 g/l performs better than INR > 6.5 in predicting mortality after POD (sensitivity 0.69, specificity 0.61), but not as well as the combined King’s College Criteria (sensitivity 0.69, specificity 0.96). Fibrinogen of ≤1 g/l in POD not meeting King’s College Criteria for transplantation may identify a group with poor prognosis. A low fibrinogen level on admission may predict death after transplant (more data required). A comparison of Gc globulin and neutrophil gelatinase- associated lipocalin in patients with liver disease S158 Table 1 (abstract P393) CKD stage Stage 1 Stage 2 Stage 3 Total n 2 44 20 66 Age (years) 64.7 (3.4) 69.9 (8.3) 75.5 (7.7) 71.5 (8.4) eGFR 92.5 (0.7) 69.4 (7.2) 52.35 (7.4) 64.9 (11.6) Creatinine 78 (1.4) 97.8 (9) 125.2 (19.9) 105.5 (18.8) Cholesterol 4.5 (0.5) 4.8 (1.1) 4.3 (0.9) 4.6 (1) BP 1 (50%) 21 (48%) 9 (45%) 31 (47%) Smoking 2 (100%) 31 (70%) 14 (70%) 49 (74%) Diabetes 0 1 (3%) 2 (10%) 3 (5%) Conclusion The majority of vascular patients undergoing elective aortic surgery in our unit have impaired renal function that is not accurately reflected by creatinine values. Management of patients with stage 2 and 3 CKD is primarily cardiovascular risk assessment with aggressive treatment of modifiable vascular risk factors [3]. The full impact of risk factor modification on perioperative outcome in vascular patients requires further detailed investigation. Table 1 (abstract P393) CKD stage Stage 1 Stage 2 Stage 3 Total n 2 44 20 66 Age (years) 64.7 (3.4) 69.9 (8.3) 75.5 (7.7) 71.5 (8.4) eGFR 92.5 (0.7) 69.4 (7.2) 52.35 (7.4) 64.9 (11.6) Creatinine 78 (1.4) 97.8 (9) 125.2 (19.9) 105.5 (18.8) Cholesterol 4.5 (0.5) 4.8 (1.1) 4.3 (0.9) 4.6 (1) BP 1 (50%) 21 (48%) 9 (45%) 31 (47%) Smoking 2 (100%) 31 (70%) 14 (70%) 49 (74%) Diabetes 0 1 (3%) 2 (10%) 3 (5%) Conclusion The majority of vascular patients undergoing elective aortic surgery in our unit have impaired renal function that is not accurately reflected by creatinine values. Management of patients with stage 2 and 3 CKD is primarily cardiovascular risk assessment with aggressive treatment of modifiable vascular risk factors [3]. The full impact of risk factor modification on perioperative outcome in vascular patients requires further detailed investigation. There were significant differences observed for Gc globulin examining 30-day survival (transplantation from ITU being analysed as ‘death’): 50 mg/l (29–94) vs 18 (4–40), respectively, AUC S158 P398 Methods In 14 domestic pigs fulminant hepatic failure was induced by surgical devascularization of the liver, and animals were monitored postoperatively for 24 hours under general anaesthesia. Seven randomly assigned pigs (DFX group) were treated with intravenous desferrioxamine (14.5 mg/kg/hour for 6 hours and 2.4 mg/kg/hour for the next 18 hours), whereas the remaining (control group) received standard care. Bronchoalveolar lavage fluid (BALF) was obtained after central line placement, after surgery, at 7 hours, and 24 hours postoperatively and was analysed f ll bi h i l d id i k f l i j Predictive value of indocyanine green clearance in acute liver failure in children: comparison with King’s College and Clichy scores J Quintero, J Ortega, J Bueno, S Flores, J Roqueta Vall d’Hebron, Barcelona, Spain Critical Care 2007, 11(Suppl 2):P398 (doi: 10.1186/cc5558) Introduction Indocyanine green clearance (ICG), measured by the percentage disappearance rate (PDR), detects alterations in liver function and may be used as a noninvasive determinant of hepatic reserve in liver failure as well as a marker of graft function following liver transplantation. The administration of blood products does not interfere with the ICG-PDR as occurs with other prognostic scores (King’s College and Clichy scores). The aims of this study were to compare in acute liver failure the ICG-PDR with King’s College and Clichy scores and to determinate its predictive value. for cell counts, biochemical and oxidative markers of lung injury. Results DFX resulted in maintenance of blood pressure (mmHg) (84 ± 27 in DFX vs 51 ± 16 in control, P < 0.05) and attenuated the increase of intracranial pressure (mmHg) (19 ± 10 in DFX vs 36 ± 9 in control, P < 0.01) at 24 hours. Protein levels in BALF were increased in controls whereas in the DFX group protein (µg/ml) was significantly lower (at 7 hours 398 ± 219 vs 187 ± 67, respectively, P < 0.01; and at 24 hours 261 ± 112 vs 162 ± 52, respectively, P < 0.05). Nitrites in BALF were elevated at 7 hours in controls whereas a reduction was observed in the DFX group (3.924 ± 3.67 µM vs 0.590 ± 0.69 µM, respectively, P < 0.05). Phospholipase A2, platelet-activating factor acetylhydrolase, nitrates, total cell counts, neutrophils and macrophages in BALF all increased in the control and DFX groups but did not differ significantly between them. Pulmonary effects of desferrioxamine in the treatment of an experimental model of fulminant hepatic failure Results DFX resulted in maintenance of blood pressure (mmHg) (84 ± 27 in DFX vs 51 ± 16 in control, P < 0.05) and attenuated the increase of intracranial pressure (mmHg) (19 ± 10 in DFX vs 36 ± 9 in control, P < 0.01) at 24 hours. Protein levels in BALF were increased in controls whereas in the DFX group protein (µg/ml) was significantly lower (at 7 hours 398 ± 219 vs 187 ± 67, respectively, P < 0.01; and at 24 hours 261 ± 112 vs 162 ± 52, respectively, P < 0.05). Nitrites in BALF were elevated at 7 hours in controls whereas a reduction was observed in the DFX group (3.924 ± 3.67 µM vs 0.590 ± 0.69 µM, respectively, P < 0.05). Phospholipase A2, platelet-activating factor acetylhydrolase, nitrates, total cell counts, neutrophils and macrophages in BALF all increased in the control and DFX groups but did not differ significantly between them. Conclusions These results suggest that COHb maybe an important mediator in haemodynamic and metabolic instability in ALF. In DCLF, COHb is an important factor in hypoxia and possible pulmonary shunting. P396 Telephone triage for a liver intensive care unit – advise or admit? Telephone triage for a liver intensive care unit – advise or admit? A Chan-Dominy, G Auzinger, W Bernal, E Sizer, J Wendon King’s College Hospital, London, UK Critical Care 2007, 11(Suppl 2):P396 (doi: 10.1186/cc5556) Objective To determine the referral pattern and organ dysfunction severity of interhospital consultations, and triage practice at a specialised liver intensive therapy unit (LITU). Objective To determine the referral pattern and organ dysfunction severity of interhospital consultations, and triage practice at a specialised liver intensive therapy unit (LITU). Methods Patients admitted with acute liver dysfunction to the ITU between January 2003 and December 2005 were considered. Sixty- eight patients with acute liver failure (ALF) and 132 patients with decompensated chronic liver failure (DCLF) had a full dataset available on day 1 of admission. Patient demographics, physiological Methods A prospective audit was conducted from 1 March to 30 November 2006, for all interhospital telephone referrals to our S159 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin References References 1. Crit Care Med 2004, 32:2079. 1. Crit Care Med 2004, 32:2079. 2. Am J Respir Cell Mol Biol 2003, 29:427. 1. Crit Care Med 2004, 32:2079. 2. Am J Respir Cell Mol Biol 2003, 29:427. P399 parameters, blood results and organ dysfunction were recorded prospectively and entered into a patient management system database (ICARE). Pulmonary effects of desferrioxamine in the treatment of an experimental model of fulminant hepatic failure Pulmonary effects of desferrioxamine in the treatment of an experimental model of fulminant hepatic failure Results There was no statistical difference in patient demo- graphics, organ failure scores or physiological parameters between the groups. The median COHb percentage for ALF was 0.9% (0.7–1.2) and for DCLF 1.5% (1.2–1.8). In patients with DCLF, COHb negatively correlated with PaO2 (r = –0.4, P = 0.05) and child Pugh (r = –0.4, P = 0.07). There was significant difference between grouped COHb and MAP in patients with ALF; there was a trend towards statistical significance with higher COHb. The arterial pH correlated with COHb in ALF (r = 0.4, P = 0.01). K Kalimeris, G Kostopanagiotou, C Routsi, V Smyrniotis, N Papoutsidakis, N Arkadopoulos, G Kampouroglou, D Kypriotis, D Panagopoulos, A Kollitza, M Lekka, G Nakos Aretaieion Hospital, University of Athens, Greece Critical Care 2007, 11(Suppl 2):P399 (doi: 10.1186/cc5559) Introduction Desferrioxamine (DFX) is a clinically approved iron chelator used to treat iron overload. It has also shown beneficial effects in experimental acute liver failure (ALF) by inhibiting oxidative damage [1]. Lung dysfunction commonly complicates ALF. Iron- mediated processes have been shown to contribute to it [2]. We hypothesized that inhibition of oxidative reactions by means of iron chelation could attenuate lung injury after ischemic ALF. Introduction Desferrioxamine (DFX) is a clinically approved iron chelator used to treat iron overload. It has also shown beneficial effects in experimental acute liver failure (ALF) by inhibiting oxidative damage [1]. Lung dysfunction commonly complicates ALF. Iron- mediated processes have been shown to contribute to it [2]. We hypothesized that inhibition of oxidative reactions by means of iron chelation could attenuate lung injury after ischemic ALF. Methods In 14 domestic pigs fulminant hepatic failure was induced by surgical devascularization of the liver, and animals were monitored postoperatively for 24 hours under general anaesthesia. Seven randomly assigned pigs (DFX group) were treated with intravenous desferrioxamine (14.5 mg/kg/hour for 6 hours and 2.4 mg/kg/hour for the next 18 hours), whereas the remaining (control group) received standard care. Bronchoalveolar lavage fluid (BALF) was obtained after central line placement, after surgery, at 7 hours, and 24 hours postoperatively and was analysed for cell counts, biochemical and oxidative markers of lung injury. P398 Methodology Between 2003 and 2006, 114 ICG-PDRs were performed in 38 children (mean age 2.6 years (range 1 month– 16 years)) with acute liver damage. ICG was administrated intra- venously and its blood concentration was detected over time by transcutaneous pulse densitometry using a commercially available bedside monitor. The PDR was performed under hemodynamic stability (systolic mean pressure >60 mmHg; saturation of central venous blood saturation >70% and CO2 arterio-venous difference <8 mmHg). Conclusion Treatment of ALF with DFX attenuates the increase of protein and nitrites in BALF, but does not seem to significantly affect phospholipase A2, platelet-activating factor acetylhydrolase, nitrates, macrophages or neutrophils. The observed effects may suggest a protective role of DFX on lung inflammation during the first 24 hours of ALF. Results The mean number of PDRs/patient was three. The mean PDR was 17% (range: 3.3–51%). In two out of 38 patients, the PDR could not be detected due to hemodynamic instability. PDR < 5% was a predictor value for irreversible liver failure (P = 0.000). In nine (25%) out of 36 patients, the PDR was <5%. Of those nine, two patients recovered its synthetic function and seven (78%) patients developed irreversible liver failure (four died of liver failure and three underwent liver transplantation) (see Table 1). The relative sensitivity of serum lipase versus amylase for radiological image-positive pancreatitis K Delaney, S Luber UT Southwestern Medical School, Dallas, TX, USA Critical Care 2007, 11(Suppl 2):P402 (doi: 10.1186/cc5562) Methods A retrospective study in a national four-bed liver ICU that treated 127 patients with ALF between 2001 and 2006. Thirty-eight of these patients were treated with terlipressin, and 10 patients (median age 42.5 years; range 15–66 years; five females) who also had an ICP and a microdialysis catheter placed in the cerebral cortex were included in this study. Concomitant measurements of mean arterial pressure (MAP), ICP, cerebral perfusion using transcranial Doppler sonography (Vmean) and cerebral concentrations of lactate and pyruvate were made before and after an increase in the NE infusion rate and i.v. injection of 1 mg terlipressin. Background Due to the absence of a ‘gold standard’ test for the diagnosis of pancreatitis, the sensitivities of pancreatic enzyme tests for pancreatitis are still debated. We compared the relative sensitivities of lipase and amylase at their upper limit of normal values for image-positive pancreatitis in a large consecutive series of patients who had simultaneous tests of amylase and lipase. Background Due to the absence of a ‘gold standard’ test for the diagnosis of pancreatitis, the sensitivities of pancreatic enzyme tests for pancreatitis are still debated. We compared the relative sensitivities of lipase and amylase at their upper limit of normal values for image-positive pancreatitis in a large consecutive series of patients who had simultaneous tests of amylase and lipase. Methods Consecutive patients with a clinical diagnosis of pancreatitis defined by constant epigastric pain and elevation of the amylase or lipase to greater than 106 U/l or 59 U/l, respectively, were imaged by abdominal sonography or computerized axial tomography (CAT) scan. All included patients had positive radiological evidence of acute pancreatitis. Results The pancreas was visualized in 399/473 (84%) patients with suspected pancreatitis and 127/399 (38%) had radiological evidence of pancreatitis. Elevation of the lipase to >59 U/l detected 127/127 cases of image-positive pancreatitis, while elevation of the amylase to >106 U/l detected 113/127 cases (88% sensitive (0.82–0.94)). All cases of acute biliary pancreatitis were detected by both the lipase and amylase. The amylase missed 14 of 65 patients with nonbiliary etiologies of pancreatitis. Four of these were alcoholics. P402 aim of this study was to determine whether terlipressin increases cerebral perfusion and to compare the effect with that of nor- epinephrine (NE). Furthermore, the effect on intracranial pressure (ICP) and cerebral concentrations of lactate and pyruvate were recorded. The relative sensitivity of serum lipase versus amylase for radiological image-positive pancreatitis P401 Relative adrenal insufficiency in patients with severe acute pancreatitis Conclusion Our study shows a high degree of relative sensitivity of the lipase compared with amylase for pancreatic injury that is demonstrable on CAT or sonographic imaging. Our findings demonstrate a relative lack of sensitivity of amylase for nonbiliary etiologies of pancreatitis. We recognize that the absolute sensitivity of lipase for image-positive pancreatitis cannot be determined by this retrospective methodology that required elevation of one marker for inclusion. J De Waele1, E Hoste1, D Baert2, K Heyndrickx3, D Rijkckaert4, P Thibo5, P Van Biervliet6, F Colardyn1 1Ghent University Hospital, Ghent, Belgium; 2AZ Maria Middelares, Ghent, Belgium; 3OLV, Aalst, Belgium; 4AZ St Lucas, Ghent, Belgium; 5AZ Palfijn, Ghent, Belgium; 6AZ Aurora, Oudenaarde, Belgium Critical Care 2007, 11(Suppl 2):P401 (doi: 10.1186/cc5561) P403 Background Inadequate cortisol levels and adrenal dysfunction may play a role in the pathophysiology of severe acute pancreatitis. This study aimed to analyse the incidence of relative adrenal insufficiency (RAI) in these patients, to identify factors associated with relative adrenal insufficiency and to describe how adrenal responsiveness affects outcome. P400 Conclusions ICG-PDR < 5% is a significant predictor of irreversible liver failure. It is a good complement of such scores for decision-making. Comparison of terlipressin and norepinephrine on cerebral perfusion, intracranial pressure and cerebral concentrations of lactate and pyruvate in patients with acute liver failure: a microdialysis study Table 1 (abstract P398) King’s score Clichy score ICG-PDR Sensitivity (%) 100 71.4 100 Specificity (%) 87 90 93 PPV (%) 64 63 78 NPV (%) 100 93 100 M Eefsen, T Dethloff, H Frederiksen, J Hauerberg, B Adel Hansen, F Stolze Larsen Rigshospitalet, University Hospital of Copenhagen, Denmark Critical Care 2007, 11(Suppl 2):P400 (doi: 10.1186/cc5560) Table 1 (abstract P398) Introduction Volume expansion and inotropic support with catecholamines are often insufficient to ensure adequate blood pressure and cerebral blood flow in acute liver failure (ALF). The S160 Available online http://ccforum.com/supplements/11/S2 The relative sensitivity of serum lipase versus amylase for radiological image-positive pancreatitis Methods Consecutive patients with a clinical diagnosis of pancreatitis defined by constant epigastric pain and elevation of the amylase or lipase to greater than 106 U/l or 59 U/l, respectively, were imaged by abdominal sonography or computerized axial tomography (CAT) scan. All included patients had positive radiological evidence of acute pancreatitis. Results NE infusion and terlipressin injection increased the MAP and Vmean (P < 0.01). Also, the ICP increased during NE infusion (P < 0.01) but not after terlipressin. The cerebral lactate concentration was unchanged during NE infusion, while it decreased after terlipressin (P < 0.05). p g p Results The pancreas was visualized in 399/473 (84%) patients with suspected pancreatitis and 127/399 (38%) had radiological evidence of pancreatitis. Elevation of the lipase to >59 U/l detected 127/127 cases of image-positive pancreatitis, while elevation of the amylase to >106 U/l detected 113/127 cases (88% sensitive (0.82–0.94)). All cases of acute biliary pancreatitis were detected by both the lipase and amylase. The amylase missed 14 of 65 patients with nonbiliary etiologies of pancreatitis. Four of these were alcoholics. Conclusion This study shows that terlipressin increases the MAP and cerebral perfusion in patients with ALF with no influence upon ICP and the cerebral concentrations of lactate and pyruvate. These findings indicate that terlipressin may be valuable, as an additive, or alternative, treatment of arterial hypotension in patients with ALF to secure brain viability. The significance of gallbladder sludge in the patient with acute pancreatitis The significance of gallbladder sludge in the patient with acute pancreatitis K Delaney, L Velez UT Southwestern Medical School, Dallas, TX, USA Critical Care 2007, 11(Suppl 2):P403 (doi: 10.1186/cc5563) Methods In a prospective observational multicenter study, a short Synacthen test (SST) was performed within 5 days after admission to the hospital in 25 patients with severe acute pancreatitis, after signed informed consent was obtained. The incidence of RAI, defined as an increment after SST of less than 9 µg/dl, was the primary endpoint of the study. Serum cortisol was measured at baseline and 30 and 60 minutes after 250 µg adrenocorticotropic hormone administration. Background The significance of gallbladder sludge as a potential cause of acute biliary pancreatitis is debated. We report the incidence and outcome of patients with gallbladder sludge in a large population of patients with pancreatitis. Methods Pancreatitis was defined as constant epigastric pain with lipase greater than three times the upper reference value for our laboratory (177 U/l). Consecutive patients with first episodes of acute pancreatitis were identified over a 2-year period and data were evaluated retrospectively. Patients were followed prospectively for 2 years more. Results The median baseline cortisol level was 26.6 µg/dl, and increased to 43.2 µg/dl and 48.8 µg/dl after 30 and 60 minutes, respectively. RAI was found in 16% of all patients, and in 27% of patients with organ dysfunction. Patients with RAI were more severely ill and had higher SOFA scores from day 4 through day 7 after admission. All patients with RAI developed pancreatic necrosis, and all of them needed surgical intervention. Mortality was significantly higher in patients with RAI (75% vs 10%, P = 0.016). Patients who died had a lower increment in cortisol levels after the SST than patients who survived. Results All patients had gallbladder ultrasound examinations. First episodes of acute pancreatitis were identified in 356 patients. Initially 236 patients had stones directly visualized in the gallbladder. Of the remaining 120 patients, 13 had sludge, 11 had a dilated common bile duct, one had a positive sonographic Murphy sign, and 95 had no abnormalities. During the time course of the study, 23 of these 120 patients were demonstrated to have stones; by the surgical pathology report (12), endoscopic retrograde cholangio-pancreatography (10), and cholecystostomy Conclusion RAI is frequent in patients with severe acute pancreatitis and organ dysfunction. Recurrence rates in patients with first episodes of acute pancreatitis Recurrence rates in patients with first episodes of acute pancreatitis K Delaney, S Luber UT Southwestern Medical School, Dallas, TX, USA Critical Care 2007, 11(Suppl 2):P404 (doi: 10.1186/cc5564) , , , Critical Care 2007, 11(Suppl 2):P404 (doi: 10.1186/cc Introduction The timing of operative intervention in patients with suspected biliary pancreatitis is debated. Recurrence rates of pancreatitis in patients with biliary lithiasis are compared in operated and nonoperated patients. Recurrences in patients with suspected nonbiliary pancreatitis are also reported. Results The two groups of 38 patients were comparable in age (52.4 and 56.5 years), ASA physical status (1.9 and 2.0), preoperative albumin concentration (39.0 and 38.1 g/l), duration of operation (5.9 and 6.1 hours), transfused red blood cells (3.3 and 2.0 l) and crystalloid infusion during surgery (5.3 and 4.5 l). In both groups there was very significant drop of albumin concentration in the first week after surgery (P < 0.001). In group 2 albumin concentrations were very significantly lower than in group 1 until the fifth postoperative day (P < 0.001). The difference diminished after the sixth postoperative day (P < 0.03). There was negative correlation between the postoperative albumin concentration and the duration of surgery (r = –0.44, P < 0.008). We found no difference in the postoperative complication rate (surgical or medical), length of stay and mortality between the groups. Introduction The timing of operative intervention in patients with suspected biliary pancreatitis is debated. Recurrence rates of pancreatitis in patients with biliary lithiasis are compared in operated and nonoperated patients. Recurrences in patients with suspected nonbiliary pancreatitis are also reported. Methods First episodes of acute pancreatitis were identified in consecutive emergency department patients over a 2-year period. Data were evaluated retrospectively and then the identified patients were then followed prospectively for 2 years more. Results Pancreatitis was defined clinically as constant epigastric pain associated with elevation of the serum lipase to greater than three times the upper reference value (177 U/l) and no other identified cause of abdominal pain. Of 356 patients with first episodes of acute pancreatitis, 259 had pancreatitis that was ultimately associated with biliary lithiasis based on abdominal ultrasound (n = 236), positive endoscopic retrograde pancreoto- graphy (n = 11), surgical pathology report (n = 11), or cholecystos- tomy (n = 1). Ninety-seven patients had no identified stones during the study period. Cholecystectomy was performed in 235/259 at the time of admission for pancreatitis. P406 Extravascular lung water following resuscitation of hemorrhagic shock in swine: comparison between Ringers’ lactate and normal saline C Phillips, B Tieu, D Hagg, M Schreiber Oregon Health & Science University, Portland, OR, USA Critical Care 2007, 11(Suppl 2):P406 (doi: 10.1186/cc5566) Extravascular lung water following resuscitation of hemorrhagic shock in swine: comparison between Ringers’ lactate and normal saline C Phillips, B Tieu, D Hagg, M Schreiber Oregon Health & Science University, Portland, OR, USA Critical Care 2007, 11(Suppl 2):P406 (doi: 10.1186/cc5566) Introduction Pulmonary edema is a common consequence of hemorrhagic shock resuscitation. The type and amount of fluid used in resuscitation may be important determinants of the amount of edema formed. Ringers’ lactate (RL) and normal saline (NS) remain common resuscitative fluids. These experiments were designed to measure the extravascular lung water (EVLW) after resuscitation from hemorrhagic shock with RL vs NS, to determine whether the fluid type results in differences in the amount of EVLW, and to determine whether there exists a threshold amount of fluid that results in the development of edema. Conclusion Cholecystectomy reduced the incidence of recurrence of pancreatitis in patients with biliary lithiasis. Recurrence rates in patients with first episodes of acute pancreatitis Reasons for nonoperative management were death (three cases), medical contraindications (15 cases), pregnancy (two cases) and delayed diagnosis due to negative abdominal sonogram (four cases). During the study period 10% (10/97) of patients without demonstrated stones returned with recurrent episodes of pancreatitis. There were two recurrences in 235 operated patients with stones (0.85%). Twelve of 19 nonoperated survivors with biliary lithiasis returned with complications of biliary lithiasis, including 10 recurrences of biliary pancreatitis (53%) and two episodes of common bile duct obstruction, one of which resulted in death from cholangitis. The median time to recurrence of pancreatitis in nonoperated patients with stones was 50 days, range 26–581 days. Conclusion Postoperative serum albumin concentrations were reduced in both groups, but more in group 2 with no albumin treatment, and in longer operations. Morbidity, mortality and length of stay were not influenced by albumin replacement. The significance of gallbladder sludge in the patient with acute pancreatitis It occurs in patients with more severe pancreatitis and is associated with an increased mortality rate. S161 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin no broad consensus is reached yet on abandoning the use of albumin in intensive care and perioperative settings for the bad prognostic value of hypoalbuminemia. As the albumin decrease in major surgery is mostly due to extravascular leakage of albumin (systemic inflammatory response), we regard hypoalbuminemia just as a marker of inflammatory response to surgery that albumin replacement cannot change. So the postoperative morbidity, mortality and length of stay would not differ in patients without albumin replacement. (one). Seven of 13 patients with sludge underwent cholestectomy and all had evidence of stones. Four of six nonoperated patients with sludge (67%) returned with recurrent pancreatitis over the course of the study. Ten of 97 patients (10%) with suspected nonbiliary etiology of the pancreatitis returned with recurrent pancreatitis over the same period. The nonoperated patients with sludge were more likely to have other risk factors for nonbiliary pancreatitis than were the operated patients. Conclusions The presence of sludge on the gallbladder ultrasound suggests the presence of stones and is associated with a high rate of recurrence of pancreatitis in nonoperated patients. Materials and methods We retrospectively studied 76 successive patients operated on in the abdomen at the Oncologic Institute in Ljubljana in 1997/98 (group 1 – postoperative hypoalbuminemia treated with 20% albumin solution) and in 2000/01 (group 2 – no albumin treatment), because of abandoning albumin use in our surgical department. We compared serum albumin concentrations in the first week after surgery (three values) as well as the postoperative complication rate and the length of hospital stay. We looked for correlation between the postoperative albumin concentration and the duration of surgery, amount of transfusion and amount of infusion during surgery. P405 Replacement of albumin after abdominal surgery Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 suprapubic Foley catheter placement, and splenectomy. The spleen was weighed and, based on randomization, either LR or NS solution was infused to replace three times the spleen weight in grams. Following a 15-minute stabilization period, a standardized Grade V liver injury (injury to a central hepatic vein) was then created using a specialized clamp. Following 30 minutes of uncontrolled hemorrhage, we blindly randomized the swine to receive either NS or RL resuscitation at 165 ml/min. Resuscitation fluid was administered to achieve and maintain the baseline mean arterial pressure (MAP) for 90 minutes post injury. suprapubic Foley catheter placement, and splenectomy. The spleen was weighed and, based on randomization, either LR or NS solution was infused to replace three times the spleen weight in grams. Following a 15-minute stabilization period, a standardized Grade V liver injury (injury to a central hepatic vein) was then created using a specialized clamp. Following 30 minutes of uncontrolled hemorrhage, we blindly randomized the swine to receive either NS or RL resuscitation at 165 ml/min. Resuscitation fluid was administered to achieve and maintain the baseline mean arterial pressure (MAP) for 90 minutes post injury. operatively. Thereafter fluid management was as in group A. Arterial blood samples were taken preoperatively and at 5 minutes, 30 minutes, 60 minutes, 120 minutes, 240 minutes and 24 hours post-tourniquet release for HNE and arterial blood gas analysis. Repeated measures of analysis of variance established a significant difference in the pattern of change of HNE levels (log transformed) and the PaO2/FiO2 ratios with time between the two groups. Follow-up t tests revealed significantly lower levels of HNE (Table 1) and also significantly higher PaO2/FiO2 ratios in Group B post-tourniquet release. operatively. Thereafter fluid management was as in group A. Arterial blood samples were taken preoperatively and at 5 minutes, 30 minutes, 60 minutes, 120 minutes, 240 minutes and 24 hours post-tourniquet release for HNE and arterial blood gas analysis. Repeated measures of analysis of variance established a significant difference in the pattern of change of HNE levels (log transformed) and the PaO2/FiO2 ratios with time between the two groups. Follow-up t tests revealed significantly lower levels of HNE (Table 1) and also significantly higher PaO2/FiO2 ratios in Group B post-tourniquet release. In conclusion, the results suggest that infusion of HES lowers HNE release from activated neutrophils in postoperative knee replacement patients and may lead to less lung injury. Toxicity of two lipid emulsions on human lymphocytes and neutrophils Toxicity of two lipid emulsions on human lymphocytes and neutrophils Toxicity of two lipid emulsions on human lymphocytes and neutrophils M Cury-Boaventura1, R Gorjão2, T Martins de Lima2, F Soriano3, R Curi2 1Cruzeiro do Sul University, São Paulo, Brazil; 2University of São Paulo, Brazil; 3Faculdade de Medicina USP, São Paulo, Brazil Critical Care 2007, 11(Suppl 2):P408 (doi: 10.1186/cc5568) Introduction The incorporation of lipid emulsions in parenteral diets is a requirement for energy and essential fatty acid supply, and may prevent many metabolic disturbances associated with intravenous feeding amino acids and glucose alone in critically ill patients. For different parenteral fat emulsions, a significant impact on the immune system has been shown. In this study, the toxicity of soybean oil-based emulsion and olive oil-based emulsion on leukocytes from healthy volunteers was investigated. Conclusion In this swine model of traumatic hemorrhagic shock, resuscitation with RL as compared with NS required less fluid to maintain goal MAP and resulted in less EVLW formation. The near fourfold difference in EVLW increase was accounted for entirely by the differences in volumes needed to maintain goal MAP with no differences seen with fluid type. This study suggests that, in order to limit increases in EVLW during early resuscitation of hemorrhagic shock prior to the arrival of blood products, RL should be used preferentially instead of NS and the volume infused limited to approximately 60 ml/kg. Methods Twenty-four volunteers were recruited and blood samples were collected before infusion of a soybean oil-based emulsion or olive oil-based emulsion, immediately afterwards and 18 hours later. The cells were studied immediately after isolation, and after 24 hours or 48 hours in culture. The following deter- minations were made: composition and concentration of fatty acids in plasma, lymphocytes and neutrophils, and lymphocyte proliferation. The toxicity was determined by plasma membrane integrity, DNA fragmentation, phosphatidylserine externalization, mitochondrial depolarization, production of reactive oxygen species and neutral lipid accumulation. Available online http://ccforum.com/supplements/11/S2 Results All animals spontaneously stopped bleeding within 12 minutes of injury after losing approximately 25% of their blood volume. There were no differences in initial blood loss between the two groups – estimated blood loss (mean ± standard error) RL group 22 ± 1.7 ml/kg vs NS group 19.0 ± 1.7 ml/kg, P = 0.15. During the resuscitative phase the NS group required more fluid to maintain the goal MAP than the RL group: 330.8 ± 38.1 ml/kg vs 148.4 ± 20.2 ml/kg, P = 0.001. There was nearly a fourfold increase in mean EVLW between the groups: 5.24 ± 1.26 ml/kg NS vs 1.46 ± 0.57 ml/kg RL, P = 0.013. The difference in EVLW was accounted for entirely by the difference in the volume infused (P = 0.008), with no difference seen with fluid type (P = 0.7). The EVLW began to increase immediately with fluid administration without exhibiting a threshold effect. An increase of 1 ml/kg EVLW occurred at a resuscitative volume of 63 ± 25 ml/kg. Neutrophil elastase suppression by medium-molecular- weight hydroxyethylstarch in orthopaedic surgery Neutrophil elastase suppression by medium-molecular- weight hydroxyethylstarch in orthopaedic surgery R Walker1, G McCarthy2 1Craigavon Area Hospital, Craigavon, UK; 2Belfast City Hospital, Belfast, UK Critical Care 2007, 11(Suppl 2):P407 (doi: 10.1186/cc5567) Results Both lipid emulsions decreased lymphocyte proliferation and induced cell death, but the effects of soybean oil-based emulsion were more pronounced. Soybean oil-based emulsion provoked apoptosis and necrosis, whereas olive oil-based emulsion caused neutrophil and lymphocyte necrosis only. Evidence is presented that lipid emulsion is less toxic to neutrophils than to lymphocytes. The mechanism of cell death induced by this lipid emulsion involved mitochondrial membrane depolarization and neutral lipid accumulation, but did not alter production of reactive oxygen species. The aim of this study was to compare the effect of hydroxyethylstarch (HES) and human albumin solution (HAS) on human neutrophil elastase (HNE) release in patients undergoing elective knee replacement surgery. Forty-three patients (ASA 1 or 2) were randomly allocated into two groups. Group A (n = 21) received 5 ml/kg of 4.5% HAS pre- operatively and a further 5 ml/kg HAS as an intraoperative replace- ment. Postoperatively the patients received Ringers’ lactate at the discretion of the anaesthetic team. Group B was given 5 ml/kg HES (Fresenius-Kabi) preoperatively and a further 5 ml/kg HES intra- Conclusions Olive oil-based emulsion can be an alternative to soybean oil-based emulsion, avoiding leukocyte death and the susceptibility of patients to infections. Table 1 (abstract P407) Group Preoperative, mean (SD) 5 minutes 30 minutes* 60 minutes* 120 minutes* 240 minutes* 24 hours A 2.31 (0.21) 2.59 (0.35) 2.74 (0.34) 2.83 (0.26) 2.74 (0.24) 2.78 (0.29) 2.68 (0.19) B 2.39 (0.25) 2.4 (0.32) 2.41 (0.15) 2.43 (0.13) 2.54 (0.2) 2.53 (0.15) 2.65 (0.31) *P < 0.01. Replacement of albumin after abdominal surgery K Mahkovic Hergouth1, L Kompan2 1Institute of Oncology, Ljubljana, Slovenia; 2Clinical Center, Ljubljana, Slovenia Critical Care 2007, 11(Suppl 2):P405 (doi: 10.1186/cc5565) K Mahkovic Hergouth1, L Kompan2 1Institute of Oncology, Ljubljana, Slovenia; 2Clinical Center, Ljubljana, Slovenia Critical Care 2007, 11(Suppl 2):P405 (doi: 10.1186/cc5565) Methods This was a randomized controlled trial using 20 female Yorkshire crossbred pigs. Animals were mechanically ventilated. Anesthesia was maintained using 2% isofluorane in 100% oxygen. Continuous hemodynamic monitoring, blood sampling, and determination of EVLW by single indicator transpulmonary dilution was done using a PiCCO plus monitor (Pulsion Medical System, Munich, Germany). The animals underwent a midline celiotomy, Introduction Replacement of albumin in hypoalbuminemic patients is not proven to reduce postoperative morbidity and mortality but S162 Available online http://ccforum.com/supplements/11/S2 Haemoglobin concentration influences the chloride– bicarbonate but not the strong ion difference–bicarbonate relationship M Mercieri, A Marcelli, C Claroni, A Mercieri University of Rome La Sapienza, Rome, Italy Critical Care 2007, 11(Suppl 2):P409 (doi: 10.1186/cc5569) Methods In this retrospective case–control study we identified patients who received more than two units of high plasma volume components from male-only donors and compared them with patients matched by severity of illness, postoperative state and number of transfusions but who received high plasma volume components from female donors. Introduction Chloride and bicarbonate concentrations share an inverse reciprocal relationship during either acidosis or alkalosis. This relationship is, in part, due to the red cell chloride shift. However, according to the Stewart quantitative approach to acid– base balance, it seems conceivable to expect a greater relationship between the strong ion difference (SID) and bicarbonate, rather then between chloride and bicarbonate. We propose that, with decreasing haemoglobin (Hb) levels, the SID preserves its independent role with respect to bicarbonate, while chloride gradually loses its relationship. Results From a database of 3,567 patients who received a total of 46,101 units fresh frozen plasma and 6,251 units apheresis platelets, we identified 112 patients who received three or more male-only donor components and 112 matched controls. Baseline characteristics, ALI risk factors and development of ALI were similar between the two groups. Arterial oxygenation (PaO2/FiO2) worsened after the female donor components (mean difference –52, 95% CI –14 to –91, P = 0.008) but not after male-only donor product transfusion (mean difference +22, 95% CI –23 to + 67, P = 0.325). Male-only component recipients had more ventilator- free days (median 28 vs 27, P = 0.006) and a trend towards lower hospital mortality (14% vs 24%, P = 0.054). Methods We retrospectively collected blood gas analysis and electrolytes, from 206 patients, measured on a single blood sample taken on admission. We calculated the apparent SID through the following formula: [Na+] + [K+] + [Ca2+] + [Mg2+] – [Cl–] – [Lact–] (mEq/l). We divided patients into three groups based on Hb levels: group A (n = 54) with Hb levels between 12 and 15 g/dl, group B (n = 104) with Hb levels between 9 and 12 g/dl, and group C (n = 48) with Hb levels below 9 g/dl. We calculated Pearson’s coefficients between the SID and bicarbonate and between chloride and bicarbonate in these three groups of patients. Table 1 (abstract P409) Table 1 (abstract P409) SID–HCO3 –, Cl––HCO3 –, Group Hb (g/dl) r/r2 P r/r2 P A 12–15 0.76/0.58 0.001 –0.6/0.36 0.001 B 9–12 0.83/0.70 0.001 –0.56/0.32 0.001 C <9 0.80/0.65 0.001 –0.31/0.09 ns ical Care 2007, 11(Suppl 2):P411 (doi: 10.1186/cc557 Introduction Red blood cell (RBC) transfusion is very often performed in critically ill patients despite its potential complications. Its effects on oxygen delivery and microcirculation are not well known. This study aimed at evaluating RBC effects in blood lactate levels (LAC) and central venous oxygen saturation (SvcO2) in patients with severe sepsis and septic shock. Conclusion These results give further validation to Stewart’s theories: the SID appears to maintain the role of an independent variable with respect to bicarbonate even at low haemoglobin levels, while chloride loses this relationship at haemoglobin levels below 9 g/dl. Methods A prospective study enrolling patients admitted to an ICU at a university hospital with severe sepsis and septic shock presenting hemoglobin (Hb) levels below 9.0 g/dl. These patients were randomized for maintaining Hb >9 g/dl (Group 1) or >7 g/dl (Group 2). Before (preT) and at least 1 hour after each transfusion (postT) LAC, SvcO2 and Hb data were collected. Data were analysed by analysis of variance, paired t test and paired Wilcoxon test. Results were considered significant if P ≤0.05. Table 1 (abstract P407) S163 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Haemoglobin concentration influences the chloride– bicarbonate but not the strong ion difference–bicarbonate relationship Conclusion In critically ill recipients of high plasma volume components, gas exchange worsened significantly after transfusion of female but not male donor components. Prospective studies are needed to evaluate the effect of AABB recommendations on outcome of transfused critically ill patients. P411 Results Correlation strength between the SID and HCO3 – was high and significant even at a Hb concentration below 9 g/dl (see Table 1). Pearson’s coefficients for chloride and bicarbonate showed a moderate but significant inverse correlation in group A and group B; eventually this correlation was completely lost in group C. Evaluation of red blood cell transfusion effects in lactate and central venous oxygen saturation in patients with severe sepsis and septic shock B Mazza, M Assuncao, F Freitas, M Jackiu, H Fernandes, F Machado Escola Paulista de Medicina – Universidade Federal de São Paulo, Brazil Critical Care 2007, 11(Suppl 2):P411 (doi: 10.1186/cc5571) P409 P409 Haemoglobin concentration influences the chloride– bicarbonate but not the strong ion difference–bicarbonate relationship M Mercieri, A Marcelli, C Claroni, A Mercieri University of Rome La Sapienza, Rome, Italy Critical Care 2007, 11(Suppl 2):P409 (doi: 10.1186/cc5569) minimize transfusion of high plasma volume components, fresh frozen plasma and apheresis platelets, from potentially alloimunized donors, especially females. The objective of this study was to evaluate the effect of transfusing components from male-only vs female donors on development of ALI, gas exchange, and outcome in critically ill patients. P409 Haemoglobin concentration influences the chloride– bicarbonate but not the strong ion difference–bicarbonate relationship O Gajic1, M Yilmaz1, R Iscimen1, D Kor1, J Winters1, B Afessa2, J Farmer1 1Mayo Clinic, Rochester, MN, USA; 2Mayo Clinic College of Medicine, Rochester, MN, USA Critical Care 2007, 11(Suppl 2):P410 (doi: 10.1186/cc5570) P412 Results The mean age of the transfused patients was 35.78 years. The sex ratio was 1.2. A total of 48.3% of the patients had trans- fusion history. Allogeneic immunization and viral serology conver- sion were reported in 2.1% of these patients. The indications were generally carried in front of chronic medical pathologies (36.9%), acute medical pathologies (28.2%) and surgical pathologies (elective 11.7%, urgent 11.2%). The haemoglobin threshold for transfusion was 7.29 g/dl and depended on the indication of the red cell transfusion: 6.16 g/dl for urgent medical pathologies, 6.22 g/dl for chronic medical pathologies, 7.74 g/dl for urgent surgical pathologies, 10.38 g/dl for elective surgery, 6.15 g/dl for urgent obstetrical pathologies. The mean platelet count was 24,000 (patients transfused by platelet units). The ABO and rhesus determination were made in 99% of the cases. A phenotypic determination was required in only 34.5% of the cases. The search for irregular agglutinins was made in 20.7% of the cases. The test of compatibility at the laboratory was practiced in 95.4% of the cases. The amount of blood transfused was 2 units. Immediate incidents were reported in 2.5% of the cases. The post- transfusion haemoglobin average was of 9.15 g/dl. Transfusion profiles in intensive care units from a university hospital M Assuncao, I Paula, L Falcao, B Mazza, M Barros, M Jackiu, H Fernandes, F Machado Universidade Federal de São Paulo, Brazil Critical Care 2007, 11(Suppl 2):P412 (doi: 10.1186/cc5572) Introduction Red blood cell (RBC) transfusion is very often performed in critically ill patients despite its potential complica- tions. New guidelines recommend that doctors should have conservative behavior regarding its use. The objective of this study was to evaluate the transfusion profile among patients in ICUs at a university hospital in Brazil. Introduction Red blood cell (RBC) transfusion is very often performed in critically ill patients despite its potential complica- tions. New guidelines recommend that doctors should have conservative behavior regarding its use. The objective of this study was to evaluate the transfusion profile among patients in ICUs at a university hospital in Brazil. Methods A prospective evaluation of all patients admitted to six ICUs (surgical–medical, private, neurosurgery, medical, pneu- mology and coronary units) that have received a RBC transfusion as indicated by assistant physicians during October/November 2005. Clinical data as well as the characteristics of the transfusion were collected and submitted to univariate statistical analysis (chi- squared and Student’s t test). National survey of transfusion practices N Frikha, R Ouezini, T Mestiri, M Bechikh, M Mebazaa, M Ben Ammar Mongi Slim Hospital, La Marsa, Tunisia Critical Care 2007, 11(Suppl 2):P413 (doi: 10.1186/cc5573) Introduction The awakening of the residual risks of blood trans- fusion leads, everywhere in the world, to efforts to reduce them. The aim of the study was to assess the transfusion practices in Tunisia. Introduction The awakening of the residual risks of blood trans- fusion leads, everywhere in the world, to efforts to reduce them. The aim of the study was to assess the transfusion practices in Tunisia. Patients and methods A multicentric prospective observational study of about 1,000 transfusions practiced during 2004 in Tunisia. Data were determined by the prescriptor of the trans- fusion. The data were analyzed with SPSS 12.0. Conclusion In patients with SvcO2 < 70 and/or Hb < 7.0 g/dl, transfusion seems to result in an improvement of perfusion parameters. However, in patients with SvcO2 > 70 or normal lactate levels, transfusion seems to impair tissue perfusion. Patients and methods A multicentric prospective observational study of about 1,000 transfusions practiced during 2004 in Tunisia. Data were determined by the prescriptor of the trans- fusion. The data were analyzed with SPSS 12.0. Transfusion from male-only vs female donors in critically ill recipients of high plasma volume components Results Thirty-six transfusions were evaluated in 21 patients (mean age 59.0 ± 15.8 years, 11 females/10 males) with APACHE II score of 13.8 ± 4.1. Each group included 18 patients. The levels of Hb preT and postT were 7.51 ± 1.03 and 8.48 ± 1.15 (P < 0.05). There was a significant difference between preT and postT SvcO2 (70.9 ± 8.66 and 73.6 ± 7.2, P = 0.01) but not in LAC levels (24.1 ± 8.9 and 22.9 ± 7.6, P = 0.45). When groups were analyzed separately, only in Group 2 was a significant difference found (P = 0.0005 and 0.05, respectively for SvcO2 and LAC). In 10 transfusions a worsening of SvcO2 postT was O Gajic1, M Yilmaz1, R Iscimen1, D Kor1, J Winters1, B Afessa2, J Farmer1 1Mayo Clinic, Rochester, MN, USA; 2Mayo Clinic College of Medicine, Rochester, MN, USA Critical Care 2007, 11(Suppl 2):P410 (doi: 10.1186/cc5570) Objective To reduce the incidence of transfusion-related acute lung injury (ALI), the American Association of Blood Banks (AABB) has recently recommended rapid implementation of strategies to S164 Available online http://ccforum.com/supplements/11/S2 P412 Results were considered significant if P ≤0.05. Discussion and conclusion The evolution of the blood transfusion was remarkable, since the use of total blood in the 1980s, with the acquisition of the first techniques of separation of the blood components. The transfusion practice in Tunisia is far from being to the standards. The results obtained make it possible to transmit to the clinician the failures of the system, to better include how to prescribe a blood product, to follow its effectiveness and its possible side effects, and to apprehend the impact of the innovated biotechnologies to improve quality of transfusion medicine in coherence with the security requirements. Results Four hundred and eight transfusions were made in 71 patients (38 females, 33 males), 35 medical/36 surgical, with a mean age 57.2 ± 8.4 years, mean APACHE II score 17.7 ± 5.3, and mean SOFA score on the day of transfusion 6.09 ± 3.99. At admission, 60 patients (84.5%) had comorbidities, 10 (14.1%) had chronic coronary disease. At transfusion, 54.9% had sepsis, severe sepsis or septic shock, and 9.9% had acute coronary syndrome. The mean hemoglobin (Hb) level at ICU admission was 9.69 ± 2.3 g/dl and the mean level that triggered transfusion was 6.88 ± 1.1 g/dl. The most important transfusion indication was Hb levels (49.8%), followed by active bleeding (31.8%). The mean number of RBC transfused per time was 1.68 ± 0.96 and the mean age of RBC was 14.3 ± 7.83 days (46.6% had more than 14 days). Adverse events occurred in 3.4%. The 28-day mortality rate was 47.1%. Only the SOFA score at the day of transfusion correlated with mortality (P = 0.004). There was no correlation with age, type of ICU, APACHE II score, total number or age of RBC, Hb at admission or Hb pretransfusion. There was a significant difference between the pretransfusion Hb (P < 0.00001) and the number of RBC transfused at the same time considering all ICU enrolled in the study (P < 0.00001). P413 observed and all these patients had preT SvcO2 > 70%. Although there was no significant correlation between a worsening in SvcO2 and preT Hb, eight of these patients were allocated to Group 1. Another 13 transfusions were done with a SvcO2 preT < 70, and 10 of them improved (> 5%) after transfusion (mean percentage of improvement = 18.9%). Only four of these patients were allocated to Group 1. Patients with high levels of preT LAC (n = 21) only improved (reduction > 10%) in 42.9% of cases. A total 53.3% of patients with normal preT LAC levels worsened (rising > 10%) postT. The mean preT Hb from these patients was 8.18 ± 0.9. Conclusion In patients with SvcO2 < 70 and/or Hb < 7.0 g/dl, transfusion seems to result in an improvement of perfusion parameters. However, in patients with SvcO2 > 70 or normal lactate levels, transfusion seems to impair tissue perfusion. observed and all these patients had preT SvcO2 > 70%. Although there was no significant correlation between a worsening in SvcO2 and preT Hb, eight of these patients were allocated to Group 1. Another 13 transfusions were done with a SvcO2 preT < 70, and 10 of them improved (> 5%) after transfusion (mean percentage of improvement = 18.9%). Only four of these patients were allocated to Group 1. Patients with high levels of preT LAC (n = 21) only improved (reduction > 10%) in 42.9% of cases. A total 53.3% of patients with normal preT LAC levels worsened (rising > 10%) postT. The mean preT Hb from these patients was 8.18 ± 0.9. observed and all these patients had preT SvcO2 > 70%. Although there was no significant correlation between a worsening in SvcO2 and preT Hb, eight of these patients were allocated to Group 1. Another 13 transfusions were done with a SvcO2 preT < 70, and 10 of them improved (> 5%) after transfusion (mean percentage of improvement = 18.9%). Only four of these patients were allocated to Group 1. Patients with high levels of preT LAC (n = 21) only improved (reduction > 10%) in 42.9% of cases. A total 53.3% of patients with normal preT LAC levels worsened (rising > 10%) postT. The mean preT Hb from these patients was 8.18 ± 0.9. Reference 1. Geddes J, et al.: Neuropathol Appl Neurobiol 2003, 29:14-22. P416 Patients and methods Sixty-eight patients (54 males/14 females) participated in the study. Thirty-two patients underwent valve(s) replacement (group A) and the remaining underwent coronary artery bypass grafting(s) (group B). The BT determination was performed according to the Mielke technique using Surgicutt devices (ITC, USA). Platelet function was evaluated by the aggregation procedure using four agonists: ADP, arachidonic acid, collagen and ristocetin at a final concentration of 4 x 10–6 M, 0.5 mg/ml, 0.19 mg/ml and 1.2 mg/ml, respectively. Shaken baby syndrome: the classical clinical triad is still valid in recent court rulings P414 Could the combination of bleeding time and platelet function predict the perioperative transfusion requirements in cardiac surgery patients? M Kataphigioti, D Karamichaleli, M Kounavi, E Iliopoulou, G Palatianos, E Melissari Onassis Cardiac Surgery Center, Athens, Greece Critical Care 2007, 11(Suppl 2):P414 (doi: 10.1186/cc5574) Introduction The reduction in platelet count and function is the most important, unsolved, nonsurgical cause of postoperative bleeding after open heart surgery. On the other hand, the bleeding time (BT), the only comprehensive test to explore primary haemostasis, detects otherwise unknown defects in platelet– vessel wall interactions. The present study was undertaken in order to clarify whether the BT and platelet function tested preoperatively could predict the perioperative transfusion requirements in cardiac surgery patients. Conclusions The Hb level that triggered transfusion was in agreement with recent guidelines regarding critically ill patients, although there was a difference between all ICUs. Despite the fact that there is a scarceness of RBC, the RBC were higher in age. The missing correlation with mortality can be due to the small sample size. S165 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Shaken baby syndrome: the classical clinical triad is still valid in recent court rulings The Geddes theory led to the speculation that subdural and retinal haemorrhage was not caused by traumatic shearing of subdural and retinal veins but by a combination of cerebral hypoxia, raised intracranial pressure and raised arterial and central venous pressure. The publication of this theory was met with scepticism by many forensic and paediatric pathologists but was enthusiastically embraced by defence attorneys. This dilemma resulted in the UK with several appeals against prior convictions of murder/manslaughter because of alleged traumatic shaking of young children. The forensic community awaited with great interest the ruling of the Court of Appeal in London on 21 July 2005. Conclusion In patients undergoing cardiac surgery with a negative history of bleeding and early interruption of antiplatelet treatment, the BT and platelet function do not offer much in the setting to predict perioperative bleeding. g pp y Court ruling of 21 July 2005 Four cases of alleged SBS were brought to the Court of Appeal in London. Two convictions were upheld, one conviction was dismissed and one conviction was reduced from murder to manslaughter. In their written judgement their Lordships clearly stated: ‘In our judgment, it follows that the unified hypothesis can no longer be regarded as a credible or alternative cause of the triad of injuries’. The Crown Prosecution Service made a press release that ‘Today’s judgement sends a clear signal validating the CPS in prosecuting Shaken Baby Syndrome cases. The Geddes theory will no longer be used by the defence.’ Court ruling of 21 July 2005 Four cases of alleged SBS were brought to the Court of Appeal in London. Two convictions were upheld, one conviction was dismissed and one conviction was reduced from murder to manslaughter. In their written judgement their Lordships clearly stated: ‘In our judgment, it follows that the unified hypothesis can no longer be regarded as a credible or alternative cause of the triad of injuries’. The Crown Prosecution Service made a press release that ‘Today’s judgement sends a clear signal validating the CPS in prosecuting Shaken Baby Syndrome cases. The Geddes theory will no longer be used by the defence.’ Shaken baby syndrome: the classical clinical triad is still valid in recent court rulings M De Leeuw1, W Jacobs2 1Algemeen Stedelijk Ziekenhuis Aalst, Essene, Belgium; 2University Hospital Antwerp, Edegem, Belgium Critical Care 2007, 11(Suppl 2):P416 (doi: 10.1186/cc5576) Introduction Subdural haemorrhage, retinal bleeding and hypoxae- mic encephalopathy have long been considered a diagnostic clinical triad for the so-called shaken baby syndrome (SBS). The classical triad, however, has been challenged in the recent past by the so- called ‘unified hypothesis’ by Geddes and colleagues [1] with subsequent implications in court rulings in suspected cases of SBS. Judicial and scientific dilemma The unified hypothesis by Geddes suggested an alternative cause for SBS injuries that did not involve significant shaking. The Geddes theory led to the speculation that subdural and retinal haemorrhage was not caused by traumatic shearing of subdural and retinal veins but by a combination of cerebral hypoxia, raised intracranial pressure and raised arterial and central venous pressure. The publication of this theory was met with scepticism by many forensic and paediatric pathologists but was enthusiastically embraced by defence attorneys. This dilemma resulted in the UK with several appeals against prior convictions of murder/manslaughter because of alleged traumatic shaking of young children. The forensic community awaited with great interest the ruling of the Court of Appeal in London on 21 July 2005. Results (1) In the immediate postoperative time, a significant reduction in haemoglobulin levels was observed in both groups compared with that of the preoperative time (13.3%, P < 0.05 for group A and 28.4%, P < 0.01 for group B). No difference existed in haemoglobulin levels between groups postoperatively. (2) Platelet values were slightly different between the groups. A significant decrease in platelet count was observed in both groups postoperatively (28.7%, P < 0.03 for group A and 22.4%, P < 0.05 for group B). (3) The results of BT and platelet activation (per- formed preoperatively) were similar for patients who underwent valve replacement and patients who underwent coronary artery bypass grafting – although in this group platelet activation with arachidonic acid and ADP was ~11% lower with both agonists. (4) The transfusion requirements were slightly higher for patients in group A, and more patients in group B received no transfusion (one vs four patients). Judicial and scientific dilemma The unified hypothesis by Geddes suggested an alternative cause for SBS injuries that did not involve significant shaking. Emergency staff is in danger B Gulalp1, O Karcioglu2 1Adana State Hospital, Adana, Turkey; 2Dokuz Eylul University, School of Medicine, Izmir, Turkey Critical Care 2007, 11(Suppl 2):P415 (doi: 10.1186/cc5575) Conclusions Diagnosing SBS is a very complex and delicate matter. The mere presence of the classic triad does not automatically or necessarily lead to a diagnosis of nonaccidental head injury or a conclusion of unlawful killing. Diagnosis of (intentional) SBS must be based on the combination of: medical elements, elements from police inquiry, and forensic and crime scene elements. Physicians, particularly those working at the medico-legal interface (such as emergency physicians), should realise that medical observations may play a pivotal role in the diagnosis of SBS. As important is the realisation that, despite alternative hypothesis in medical literature, the classical triad of symptoms (subdural haemorrhage, retinal bleeding, hypoxaemic encephalopathy) is still valid as diagnostic for SBS according to recent (UK) court ruling. Objective To investigate the ratio and characteristics of aggression, threat and physical violence directed towards staff in emergency departments as a model of state hospitals. Objective To investigate the ratio and characteristics of aggression, threat and physical violence directed towards staff in emergency departments as a model of state hospitals. Methods A questionnaire were filled in by the staff working in the emergency department of three high-volume inner-city state hospitals. The individualized data collected were relevant to the pattern of violence, age, sex, number of years in the profession, nature of the job, and the behavioral characteristics of assailants, and outcome of incidents. The data were abstracted between 1 May and 31 May 2006. Results A total of 109 staff reports were reviewed. The relationship of aggression with sex, age and years of experience were insignificant (P values were 0.464, 0.692, and 0.298, respectively), while profession was very significantly related (P = 0.000). The relation between threat and sex is P = 0.311, experience 0.994, profession 0.326, age 0.278. The relationship of threat with sex, years of experience, profession and age were insignificant (P values were 0.311, 0.994, 0.326, and 0.278, respectively). On the other hand, physical assault was found significantly related to sex, years of experience, profession and age (P values were 0.042, 0.011, 0.000, and 0.000, respectively). A comparison of the confusion assessment method for the intensive care unit and the NEECHAM confusion scale in intensive care delirium assessment A comparison of the confusion assessment method for the intensive care unit and the NEECHAM confusion scale in intensive care delirium assessment Methods Were admitted to the ICU 29 patients with OPP. The data were treated by SPSS 14 for Windows and the analysis consisted of a descriptive study, analytic study (chi-square analysis, Spearman association analysis) and comparison between groups (Student t analysis, Wilcoxon Mann–Whitney and Kolmogorov–Smirnov tests). The receiver operating characteristic (ROC) was applied for the Sequential Organ Failure Assessment (SOFA) score. B Van Rompaey1, L Bossaert2, L Shortridge-Bagett1, M Schuurmans1, S Truijen1 1Universiteit Antwerpen, Wilrijk, Belgium; 2Universitair Ziekenhuis, Edegem, Belgium Critical Care 2007, 11(Suppl 2):P419 (doi: 10.1186/cc5579) B Van Rompaey1, L Bossaert2, L Shortridge-Bagett1, M Schuurmans1, S Truijen1 1Universiteit Antwerpen, Wilrijk, Belgium; 2Universitair Ziekenhuis, Edegem, Belgium Critical Care 2007, 11(Suppl 2):P419 (doi: 10.1186/cc5579) Results Twenty-nine patients were included in the study, 21 males and eight females. The mean age of the males was 47.71 years (SD = 13.58) and of females was 41.0 years (SD = 11.66), and 62.7% were from a rural area and 37.3% from an urban area. Mortality does not have a significant statistic relation (P > 0.05) with toxicity of organophosphate, time and doses of atropine. However, statistical significance was found between mortality and: (a) time between ingestion of the poison and treatment (Spearman test, rs = –0.596, P < 0.05), (b) muscarinic manifestations (chi- square test, χ2 = 4.152, P < 0.05), (c) time of oximes (Kolmogorov–Smirnov test with Z = 1.439, P < 0.05) and doses of oximes (Kolmogorov–Smirnov test with Z = 1.412, P < 0.05). The ROC analysis reveals that for the respiratory SOFA at 9 days, the area under the ROC curve was 0.917; this means that this SOFA score can predict correctly in 91.7% of the cases. Introduction Reports indicate an incidence of intensive care delirium of 11–87%. The confusion assessment method for the intensive care unit (CAM-ICU) is widely used in delirium assess- ment in ICUs. However, its binomial results constrain the evaluation of severity. The NEECHAM confusion scale has recently been validated for use in the ICU and uses a numeric assessment. This scale allows the patients to be classified in four categories of delirium severity (normal, at-risk, mild to early, moderate to severe). In this study we investigated the diagnostic value of the NEECHAM referring to the CAM-ICU. A comparison of the confusion assessment method for the intensive care unit and the NEECHAM confusion scale in intensive care delirium assessment Methods A consecutive sample of 106 patients in a mixed ICU (cardiac surgery (CS) 35%, noncardiac surgery (NCS) 26%, internal medicine (IM) 39%, age 62 ± 14 years, male 63%) was assessed after a stay in the ICU ≥24 hours. All patients with a Glasgow Coma Scale ≥10 and age ≥18 years were included. A nurse researcher simultaneously assessed both scales once daily in the morning. A total of 272 paired observations were made. Data were analyzed using the NEECHAM cut-off values of ≤26 (at-risk), ≤24 (mild delirium), and ≤19 (severe delirium). Conclusion In our study we concluded that the mortality rate was increased with prolonged perfusion of oximes and with muscarinic manifestations of OPP but not with the time and dose of atropine. The respiratory SOFA score at 9 days matches with prediction in above 90% of the cases. P418 Results Using the CAM-ICU the overall prevalence was 15%. Prevalences in CS, NCS and IM were 9%, 14% and 21%, respectively. Using the NEECHAM scale, the overall prevalence was 33% (16.5% mild, 16.5% severe) and 36%, 21% and 38% for the three patient categories, respectively. Sensitivity was 100%, specificity was 79%, positive predictive value was 46% and negative predictive value was 100%. Using the cut-off value ≤19, sensitivity was 83% and specificity was 96%. All positive CAM- ICU patients were detected by the NEECHAM (85% severe, 15% mild). However, 21% of the CAM-ICU negative patients had a NEECHAM value that diagnoses delirium (4% severe, 17% mild). Consequently, 27% of the CS group (19% severe, 8% mild), 7% of the NCS group (7% mild) and 17% of the IM group (2% severe, 15% mild) were diagnosed to be delirious using the NEECHAM and not delirious using the CAM-ICU. Reference organophosphate poisoning (OPP). The aim of the study was to determine the relation between mortality and: (a) toxicity of organophosphate, (b) time between ingestion and management of the patient, (c) coligernic manifestations, (d) time and doses of oximes and atropine. Reference 1. Ely EW, et al.: Crit Care Med 2004, 32:106-112. Reference 1. Ely EW, et al.: Crit Care Med 2004, 32:106-112. Approaches of Turkish anesthesiologists to delirium observed in intensive care unit patients Approaches of Turkish anesthesiologists to delirium observed in intensive care unit patients Approaches of Turkish anesthesiologists to delirium observed in intensive care unit patients N Gokmen, L Iyilikci, S Kucukguclu, B Kuvaki, L Ciftci, A Gunerli Dokuz Eylul University, School of Medicine, Izmir, Turkey Critical Care 2007, 11(Suppl 2):P418 (doi: 10.1186/cc5578) Objective To determine attitudes and practices of the Turkish anesthesiologists and residents about delirium in the ICU. Methods An anonymous questionnaire consisting of 22 questions [1] was mailed to 258 anesthesiologists and residents. [ ] g Results One hundred and fifty-four questionnaires were returned (60% response). Of the respondents, 57% were male and 61% were residents. One-half of respondents work in hospitals with more than 800 beds; 65% of respondents had an ICU facility of 7–12 beds. Seventy-two percent of the respondents had seen delirium in the ICU and also 70.2% of these respondents observed delirium in <25% of patients who were on mechanical ventilation. Although delirium was accepted a significant or very serious problem by 92.5% of the respondents, underdiagnosis was acknowledged by 74%. Routine screening for delirium was performed by 41.6% of the anesthesiologists and 88.1% of them were repeating daily. Clinical assessment was used in 76.7% of the screenings. Delirium was treated with haloperidol and benzodiazepine by 61.5% and 24% of the respondents. Of the respondents, 93.4% were not able to attend a meeting related to delirium and 67.6% did not read even an article about delirium. Conclusions Turkish anesthesiologists and residents consider delirium a relatively common and serious problem. However, they seldom perform screening tests and try to update their knowledge regarding delirium. Conclusion The NEECHAM delirium scale identified all cases of delirium that were detected by the CAM-ICU. Moreover, additional delirious patients were identified, especially in the CS group. In this pilot experience, the NEECHAM scale was a valuable screening tool for intensive care. Organophosphate poisoning and related mortality with oxime perfusion Organophosphate poisoning and related mortality with oxime perfusion A Bartolo1, O Caetano1, M Costa1, R Milheiro1, A Carvalho1, A Braga2 1Hospital Senhora Oliveira, Guimaraes, Portugal; 2University of Minho, Braga, Portugal Critical Care 2007, 11(Suppl 2):P417 (doi: 10.1186/cc5577) Conclusion Violence to the staff is common. There is not a significant relationship between aggression, threat and personal characters. However, male sex, >5 years experience, emergency doctor, ≥31 years of age are the risk factors for physical violence. Introduction A retrospective study performed between 1 January 2001 and 31 October 2006 in patients admitted to the ICU with S166 Available online http://ccforum.com/supplements/11/S2 P422 Conclusion Delirium is badly recognized in the ICU by intensivists and ICU nurses. In view of the impact of delirium on ICU and hospital stay, more attention should be paid to the implementation of a delirium screening instrument during daily ICU care. Evaluation of two sedation techniques in a casualty department Evaluation of two sedation techniques in a casualty department M Moustafa1, M Borai2 1Faculty of Medicine, Assiut University, Alain, United Arab Emirates; 2Alain Hospital, Alain, AbuDhabi, United Arab Emirates Critical Care 2007, 11(Suppl 2):P422 (doi: 10.1186/cc5582) P420 We investigated whether intensivists and ICU nurses could clinically identify the presence of delirium in ICU patients during daily care. Methods All patients in a 3-month period who stayed >48 hours in the ICU were evaluated daily for the presence or absence of delirium by treating intensivists and ICU nurses responsible for daily care. Patients were evaluated independently for the occurrence of delirium by a trained group of ICU nurses who were not involved in the daily care of the patients under study. Since communication with ventilated patients is compromised due to the inability to speak, a specific scoring system was used (confusion assessment method for the intensive care unit (CAM-ICU)), which has been developed for the evaluation of the presence of delirium. Delirium as judged present by this CAM-ICU correlates well with a DSM-IV delirium diagnosis by a trained psychiatrist. Values are expressed as the median and interquartile range (IQR). Results During the study period, 46 patients (30 males, 16 females), age 73 (IQR = 64–80) years with an ICU stay of 6 (4–11) days were evaluated. CAM-ICU scores were obtained during 481 patient-days. Considering the CAM-ICU as the gold standard, delirium occurred in 50% of the patients with a duration of 3 (1–9) days. Days with delirium were poorly recognized by doctors (sensitivity = 29.8%; specificity = 99.7%; PPV = 99.6%) and ICU nurses (sensitivity = 35.6%; specificity = 97.8%; PPV = 84%). Patients with a delirium were longer on the ventilator (6 (4–25) days), and had a longer ICU (9 (6–26) days) and hospital stay (29 (21–41) days) than those without delirium during their ICU stay (4 (1–6), P = 0.01; 5 (3–8), P = 0.002; and 19 (7–30), P = 0.01), respectively. APACHE II and SAPS II scores were comparable in both groups. Conclusions There is still a great educational potential for improving the use of sedation protocols and implementing sedation scoring systems and the wake up test in Danish ICUs. This potential could perhaps reduce the incidence of withdrawal symptoms. Effort should also be placed in implementing the sedation protocol in the ICU, illustrated by the differences in numbers of doctors and nurses having a sedation protocol. P420 The occurrence of delirium is severely underestimated by intensivists and intensive care unit nurses during daily ICU care The occurrence of delirium is severely underestimated by intensivists and intensive care unit nurses during daily ICU care The occurrence of delirium is severely underestimated by intensivists and intensive care unit nurses during daily ICU care P Spronk, B Riekerk, S Elias, J Rommes, J Hofhuis Gelre Ziekenhuizen Location Lukas, Apeldoorn, The Netherlands Critical Care 2007, 11(Suppl 2):P420 (doi: 10.1186/cc5580) P Spronk, B Riekerk, S Elias, J Rommes, J Hofhuis Gelre Ziekenhuizen Location Lukas, Apeldoorn, The Netherlands Critical Care 2007, 11(Suppl 2):P420 (doi: 10.1186/cc5580) Introduction Patients improve faster in the ICU if sedatives are stopped as soon as possible with inherent occurrence of sleeping disorders, and delirium, which could compromise the recovery Introduction Patients improve faster in the ICU if sedatives are stopped as soon as possible with inherent occurrence of sleeping disorders, and delirium, which could compromise the recovery S167 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Results Twenty-nine (82.9%) out of a total of 35 possible hospitals answered, including 113 (57.7%) answers out of a total of 196 possible answers. Ninety-seven per cent of the physicians were specialists in anaesthesiology. Eighty-seven per cent of the nurses were certified intensive care nurses. Forty-seven per cent were from university hospitals. Twenty-six per cent had a sedation protocol, 37% of the physicians and 14% of the nurses. Only one-third of the ICUs had a protocol for sedation. Sixty-eight per cent having a protocol used it always or often, whereas 32% never use it. Sixty- seven per cent had a sedation scoring system in their departments. The scoring systems used was: Ramsay 49%, Sedation Agitation Score 10% and own (locally made) scoring system 41%. Twenty- two per cent answered that the scoring systems was always used, 58% often and in 20% the scoring systems was seldom used. Forty per sent use the ‘wake-up call’ test, 63% physicians and 37% nurses. Sixty per cent answered ‘no we do not use’ the wake-up call test, 47% physicians and 53% nurses. Withdrawal symptoms were experienced more than three times as frequently by nurses compared with physicians (31% vs 9%). Five times as many experienced withdrawal symptoms in the group not having a sedation and analgesia protocol (84% vs 16%). process and prolong the ICU stay. Sedation practices in Denmark Sedation practices in Denmark We compare the efficacy, adverse events, and recovery duration of etomidate and propofol for use in procedural sedation in the emergency department (ED). A randomized nonblinded prospective trial of adult patients undergoing procedural sedation for painful procedures in the ED was made. Patients received either propofol or etomidate. Doses, vital signs, nasal end-tidal CO2 (etco2), pulse oximetry, and bispectral electroencephalogram analysis scores were recorded. Subclinical respiratory depression was defined as a change in etco2 greater than 10 mmHg, an oxygen saturation of less than 92% at any time, or an absent etco2 waveform at any time. Clinical events related to respiratory depression, including an increase in supplemental oxygen, the use of a bag-valve-mask apparatus, airway repositioning, or stimulation to induce breathing, were noted. Etomidate and propofol appear equally safe for ED procedural sedation. Etomidate had a lower rate of procedural success and induced myoclonus in 20% of patients (see Table 1). K Espersen1, M Skielboe2, T Jensen1 1Rigshospitalet, Copenhagen, Denmark; 2University Hospital Gentofte, Denmark Critical Care 2007, 11(Suppl 2):P421 (doi: 10.1186/cc5581) Critical Care 2007, 11(Suppl 2):P421 (doi: 10.1186/cc5581) Introduction The interest of sedation in ICU patients has been increasing the last 10 years. The benefits of protocol-driven care have become evident. Objective The aim of the study was to describe current practice of sedation in Danish ICUs addressing the use of protocols and the wake-up call test. Methods Two doctors and two nurses from all the Danish adult ICUs were identified to participate in an Internet-based survey. These persons answered questions about sedation practices, use of sedation scorings systems, and withdrawal symptoms. S168 Table 1 (abstract P422) Agent Etomidate (n = 53) Propofol (n = 55) Subclinical respiratory depression Yes (n = 18) No (n = 35) Yes (n = 23) No (n = 32) Increased supplemental oxygen 1/9 (2.1, 0.9–11.2) 2/34 (2.9, 0.8–7.2) 2/23 (4.4, 1.2–14.4) 1/32 (1.6, 0.2–5.5) Bag-valve mask (%) 2/18 (6.9, 1.9–13.9) 0/34 (0, 0–2.3) 2/23 (4.4, 1.4–11.9) 0/32 (0, 0–2.7) Airway repositioning 3/18 (9.7, 2.9–16.0) 3/34 (5.1, 1.4–8.7) 3/23 (6.5, 1.5–11.6) 3/31 (4.7, 1.1–8.0) Stimulation to induce breathing 4/18 (11.1, 5.1–19.6) 2/34 (2.9, 0.8–7.1) 3/23 (7.6, 3.2–14.5) 3/31 (4.7, 1.8–9.6) Comparison of dexmedetomidine with propofol/ midazolam in sedation of long-stay intensive care patients: a prospective randomized, controlled, multicenter trial Comparison of dexmedetomidine with propofol/ midazolam in sedation of long-stay intensive care patients: a prospective randomized, controlled, multicenter trial J Takala1, S Nunes2, I Parviainen3, S Jakob1, M Kaukonen4, S Shepherd5, R Bratty5, E Ruokonen3 1University Hospital Bern, Switzerland; 2Tampere University Hospital, Tampere, Finland; 3Kuopio University Hospital, Kuopio, Finland; 4Helsinki University Hospital, Helsinki, Finland; 5Orion Pharma, Helsinki, Finland Critical Care 2007, 11(Suppl 2):P423 (doi: 10.1186/cc5583) Introduction Sedation is a major problem in long-stay intensive care patients despite use of sedation stops and scores. We hypothesized that the α2-adrenoceptor agonist dexmedetomidine (DEX) is at least equivalent to standard-of-care sedation (SOC), and may reduce the length of ICU stay and improve other clinically relevant outcomes. Results Demographic data (age, gender, trauma severity score) were comparable in both groups. The waking time was significantly shorter in G2 (5 ± 8 min) compared with G1 (35 ± 20 min) (P < 0.05). The mICP was more stable in G2 (9 ± 4 mmHg) compared with G1 (10 ± 9 mmHg) (P = 0.02). The mCPP were comparable in G1 (62 ± 10 mmHg) and in G2 (63 ± 0.2 mmHg) but with a 24% swing in dose requirement adaptation of Ne in G1 compared with a 6% daily swing in G2 (P < 0.02). Methods We performed a pilot (n = 85), phase III, multicenter, prospective, randomized, double-blind, double-dummy, active comparator (SOC: either propofol or midazolam) study to define the feasibility and size of a pivotal trial. Patients with expected ICU stays ≥48 hours and a need for sedation for at least 24 hours after randomization were included within the first 72 hours of ICU stay. The maximum duration of study sedation was 14 days, with a 45- day follow-up from randomization. Sedation was Richmond Agitation Sedation Scale (RASS)-score targeted, with daily sedation stops. Conclusion By using a multimodal short-acting sedation protocol based on remifentanil and NMDA-antagonist receptors we were able to provide adequate sedation in brain trauma patients. Neurological parameters were respected with this regimen, avoiding the risk of secondary patient hemodynamic destabilisation during the waking periods. Inhalational sedation during transport to the intensive care unit SEV infusion was started in the ICU after gas monitoring. Twenty-one patients scheduled for propofol sedation served as controls. During transport all patients were ventilated with Oxylog2000 (Dräger, Germany), vital parameters were monitored, and the Ramsay Score (RS) was assessed at five time points. If necessary, propofol injections of 0.5 mg/kg were given. Statistics were t test for parametric data (mean ± standard deviation), U test for nonparametric data (median (interquartile range)), SPSS 11.04. Results The age, weight, duration of anaesthesia (ACD/controls 7.3 ± 2.0/6.3 ± 2.2 hours), total sufentanil (124 ± 75/118 ± 57 µg) and transport time (16.3 ± 2.7/17.0 ± 2.7 min) were not different between groups, and neither were heart rates, mean arterial pressures and RS at five time points during transport. ACD patients needed less propofol injections (0 (0–1)/3 (2–4), P < 0.001) Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Inhalational sedation during transport to the intensive care unit Inhalational sedation during transport to the intensive care unit M Bellgardt, C Sirtl, M Bergmann, D Weyhe, A Terporten, H Laubenthal, A Meiser St Josef-Hospital, Ruhr-Universität, Bochum, Germany Critical Care 2007, 11(Suppl 2):P425 (doi: 10.1186/cc5585) Introduction Inhalational ICU sedation is increasingly applied since the introduction of AnaConDa® (Sedana Medical, Sweden). This anaesthetic-conserving device (ACD) retains exhaled sevofluorane (SEV) and resupplies it during inspiration [1]. A syringe pump delivers liquid SEV into the device. Since January 2004 we have used the ACD as a standard practice. Our patients anaesthetised with SEV in the OR and scheduled for ICU sedation with SEV only need propofol on transport. Could this be avoided when using the ACD during transport? Introduction Inhalational ICU sedation is increasingly applied since the introduction of AnaConDa® (Sedana Medical, Sweden). This anaesthetic-conserving device (ACD) retains exhaled sevofluorane (SEV) and resupplies it during inspiration [1]. A syringe pump delivers liquid SEV into the device. Since January 2004 we have used the ACD as a standard practice. Our patients anaesthetised with SEV in the OR and scheduled for ICU sedation with SEV only need propofol on transport. Could this be avoided when using the ACD during transport? Conclusion DEX is well tolerated and comparable with SOC in long-term sedation, but not suitable as the sole agent for deep sedation. DEX enhances the patient’s ability to communicate. Its effects on relevant outcomes (for example, duration of mechanical ventilation) should be tested in a large randomized controlled trial. Methods Forty-one patients after major abdominal surgery were included in this quality assurance project. In 20 patients the ACD was inserted into the anaesthesia circuit to take up warmth, humidity and SEV for 15 minutes and used for transport. SEV infusion was started in the ICU after gas monitoring. Twenty-one patients scheduled for propofol sedation served as controls. During transport all patients were ventilated with Oxylog2000 (Dräger, Germany), vital parameters were monitored, and the Ramsay Score (RS) was assessed at five time points. If necessary, propofol injections of 0.5 mg/kg were given. Statistics were t test for parametric data (mean ± standard deviation), U test for nonparametric data (median (interquartile range)), SPSS 11.04. Methods Forty-one patients after major abdominal surgery were included in this quality assurance project. In 20 patients the ACD was inserted into the anaesthesia circuit to take up warmth, humidity and SEV for 15 minutes and used for transport. P423 during 6.4 (± 4) days were prospectively randomized into two groups (G1 n = 32; G2 n = 36) using different sedation protocols to reach a mean hourly Ramsay Score of 4. Sedation in G1 was based on morphine (0.1 ± 0.1 mg/kg/hour) and midazolam (0.4 ± 0.4 mg/kg/hour); in G2 on remifentanil (0.25 ± 0.25 µg/kg/min), magnesium (0.08 g/kg/day), ketamine (0.15 ± 0.15 µg/kg/min), clonidine (0.001 ± 0.001 µg/kg/min) and propofol (2 ± 1.5 mg/kg/ hour). The cerebral parameters (mean intracranial continuous pressure (mICP); mean cerebral perfusion pressure (mCPP)) and the needs of norepinephrine (Ne) were evaluated hourly. Preloading was adapted by a continuous central venous pressure measurement before Ne adaptation requirements to keep the mCPP over 60 mmHg. For statistical analysis a Shapiro–Wilk test, a Wilcox test and a Student t test were used. P425 Results Forty-one patients received DEX and 44 SOC (28 propofol). The goal was moderate (RASS 0 to –3) sedation in most patients (78% in DEX and 80% in SOC). Patients were at the target RASS 55% (DEX) and 57% (SOC) of the sedation time (not significant): for RASS target 0 to –3, 68% (DEX) and 64% (SOC) of the time (not significant) and for RASS target –4, 31% (DEX) and 63% (SOC), respectively (P = 0.006). Median time from admission/randomization to ICU discharge was similar (DEX 6.6/5.7 days, SOC 6.7/5.5 days, not significant). Mechanical ventilation was shorter for DEX with RASS target 0 to –3 (DEX 70.2 hours, SOC 92.5 hours, P = 0.027), and patients’ ability to communicate (multidimensional visual analog scale) was better with DEX (P < 0.001). Occurrence rates and number of patients with overall and serious adverse events were similar. P424 Multimodal short acting sedation using NMDA antagonist and remifentanil in brain trauma patients: a prospective randomised study Table 1 (abstract P422) S168 Available online http://ccforum.com/supplements/11/S2 Remifentanil vs conventional sedation in The Netherlands: a pharmacoeconomic model analysis M Al, L Hakkaart, S Tan, P Mulder, J Bakker Erasmus MC, Rotterdam, The Netherlands Critical Care 2007, 11(Suppl 2):P427 (doi: 10.1186/cc5587) Conclusions AnaConDa® effectively retains SEV in patients and permits inhalational sedation during >15 minutes transport. Hemo- dynamic stability and depth of sedation are as good as the standard regime with Propofol. Less SEV exhaled by the patients during transport also means less contamination of the workplace. Reference Introduction The goal of this study was to compare the duration of mechanical ventilation (MV), the length of stay (LOS) and the direct medical costs of remifentanil-based sedation (RS) vs conventional sedation (CS) in ICU patients requiring MV. 1. A Meiser, H Laubenthal: Best Pract Res Clin Anaesthesiol 2005, 19:523-538. Methods A Markov model was developed based on UltiSAFE, a recent Dutch open-label randomized controlled study that included patients with an expected MV time of 2–3 days. Study medication was either CS (morphine or fentanyl combined with propofol, midazolam or lorazepam according to Dutch guidelines) or RS (remifentanil, combined with propofol when required). The LOS on the ICU, the time at which the patient was eligible for weaning or extubation and the actual time of weaning and extubation, plus all study drugs with all adjustments in dosage, were recorded. The model describes the patient flow on the ICU. Three states were defined: MV before weaning, MV after weaning has started before extubation, post-MV before discharge. At every hour, patients either stay at the current state, move to the next state or die. Transition probabilities and the costs of the study drugs were derived from UltiSAFE, whereas all other direct medical costs on the ICU were estimated in a separate Dutch monocenter micro-costing study. All costs were measured from the hospital perspective with 2006 as the reference year. The time horizon used in the model was 28 days. Results From the trial data, it was estimated that the costs of RS on MV before the start of weaning amount to €22 per hour, compared with €15 for the CS treatment. After the start of weaning, these costs decrease to €8 per hour for RS and €2 per hour for CS. P427 and reached the ICU with a similar RS (5 (4.5–5)/5 (4.75–5)). End-tidal SEV concentrations were similar in the OR (1.3 ± 0.2/ 1.2 ± 0.2 vol%), but different when arriving in the ICU (0.6 ± 0.2/ 0.2 ± 0.1 vol%, P < 0.001). Pharmacokinetics of single intravenous bolus administration of propofol in preterm and term neonates Pharmacokinetics of single intravenous bolus administration of propofol in preterm and term neonates K Allegaert1, M Rayyan1, A Debeer1, H Devlieger2, G Naulaers1 1University Hospital Gasthuisberg, Leuven, Belgium; 2A.Z. Gasthuisberg, Leuven, Belgium Critical Care 2007, 11(Suppl 2):P426 (doi: 10.1186/cc5586) Background The aim of this study is to describe maturational aspects of propofol pharmacokinetics following single intravenous bolus administration in childhood. Methods Seventy propofol blood–time profiles were collected in nine neonates (mean weight 2.4, range 0.91–3.8 kg) by arterial blood samples up to 24 hours after administration of a single intravenous bolus of propofol (3 mg/kg over 10 s) before elective chest tube removal. Concentration–time curves obtained for every individual neonate were interpreted by two-stage analysis as two- compartment and three-compartment open models. These newly collected observations following intravenous bolus administration of propofol in preterm and term neonates (n = 9) were combined with individual pharmacokinetic estimates in toddlers (n = 12) and young children (n = 10) [1,2]. Data were reported by the median and range. The Wilcoxon test or linear correlation were used to analyse the pharmacokinetic findings in neonates, toddlers and young children. Results The blood–concentration curves obtained for every individual patient were interpreted by two-stage analysis as a three- compartment open model in a cohort of 31 patients with a median weight of 11.2 (range 0.91–24) kg and a median postmenstrual age of 108 (range 27–405) weeks. The median clearance was 36.8 (range 3.7–78.1) ml/kg/min, the median apparent volume of distribution at steady state (Vss) was 7.6 (1.33–15.6) l/kg and the median final serum elimination half-life was 377 (range 27–1134) minutes. Median clearance was significantly lower in neonates compared with toddlers and older children (P < 0.01) and these differences remained significant after allometric scaling (ml/kg 0.75/min). A significant correlation between Vss and postmenstrual age (r = 0.61, 95% CI 0.32–0.8, P < 0.004) was observed. Conclusion Compared with CS, RS seems to be the preferred regimen for patients with an expected MV time of 2–3 days. It not only significantly decreases the length of ICU stay and the total costs but also significantly reduces the duration of MV, which is a risk factor for ventilator-associated morbidity. Multimodal short acting sedation using NMDA antagonist and remifentanil in brain trauma patients: a prospective randomised study F Meurant, Z Ahdach Kirchberg, Luxembourg State, Luxembourg Critical Care 2007, 11(Suppl 2):P424 (doi: 10.1186/cc5584) Introduction We hypothesize that using a multimodal short-acting sedation regimen based on remifentanil and NMDA-antagonist receptors such as ketamine, clonidine and magnesium will improve cerebral protection and make clinical patient examination easier without hemodynamic impairments. Introduction We hypothesize that using a multimodal short-acting sedation regimen based on remifentanil and NMDA-antagonist receptors such as ketamine, clonidine and magnesium will improve cerebral protection and make clinical patient examination easier without hemodynamic impairments. Results The age, weight, duration of anaesthesia (ACD/controls 7.3 ± 2.0/6.3 ± 2.2 hours), total sufentanil (124 ± 75/118 ± 57 µg) and transport time (16.3 ± 2.7/17.0 ± 2.7 min) were not different between groups, and neither were heart rates, mean arterial pressures and RS at five time points during transport. ACD patients needed less propofol injections (0 (0–1)/3 (2–4), P < 0.001) Results The age, weight, duration of anaesthesia (ACD/controls 7.3 ± 2.0/6.3 ± 2.2 hours), total sufentanil (124 ± 75/118 ± 57 µg) and transport time (16.3 ± 2.7/17.0 ± 2.7 min) were not different between groups, and neither were heart rates, mean arterial pressures and RS at five time points during transport. ACD patients needed less propofol injections (0 (0–1)/3 (2–4), P < 0.001) Methods Sixty-eight ventilated brain trauma patients (mean Glasgow Coma Scale: 5 ± 3) with controlled invasive ventilation S169 and reached the ICU with a similar RS (5 (4.5–5)/5 (4.75–5)). End-tidal SEV concentrations were similar in the OR (1.3 ± 0.2/ 1.2 ± 0.2 vol%), but different when arriving in the ICU (0.6 ± 0.2/ 0.2 ± 0.1 vol%, P < 0.001). Remifentanil vs conventional sedation in The Netherlands: a pharmacoeconomic model analysis The LOS on the ICU was 9.2 days in the CS group vs 8.1 days in the RS group (difference 1.1, 95% CI 0.6–1.5), whereas the length of time on MV was 6.3 days and 5.2 days, respectively, with a difference of 1.1 day (95% CI 0.6–1.6). The average total 28-day costs were €15,911 in the CS group vs €14,855 in the RS group, resulting in RS related cost-savings of €1,056 (95% CI €58–2,054). 1. Murat I, et al.: Anesthesiology 1996, 84:526-532. P428 Assessment and management of pain in children in A&E: are we doing it the right way? A Kage, A Mohammed Calderdale Royal Hospital, Halifax, UK Critical Care 2007, 11(Suppl 2):P428 (doi: 10.1186/cc5588) Conclusions Propofol disposition is significantly different in neonates compared with toddlers and young children, reflecting both ontogeny and differences in body composition. Based on the reduced clearance of propofol, accumulation during repeated administration and longer recovery time are more likely to occur in neonates. Introduction Pain management is one of the most important components in patient care. The severity of the pain should be assessed effectively and weight-based analgesia should be given. The BAEM Clinical Effectiveness Committee standard of analgesia for moderate and severe pain within 20 minutes of arrival in A&E should be applied to children in all A&E Departments Introduction Pain management is one of the most important components in patient care. The severity of the pain should be assessed effectively and weight-based analgesia should be given. The BAEM Clinical Effectiveness Committee standard of analgesia for moderate and severe pain within 20 minutes of arrival in A&E should be applied to children in all A&E Departments Methods A retrospective study. Five casualty cards with soft tissue injury and fractures in children under 16 years old were picked randomly every day from January 2005. The assessment and management of pain was recorded in each case. A validated pain score tool – Alder Hey triage pain score – was introduced April 1. Murat I, et al.: Anesthesiology 1996, 84:526-532. 2 Saint-Maurice C et al : Br J Anaesth 1989 63:667-670 1. Murat I, et al.: Anesthesiology 1996, 84:526-532. 2. Saint-Maurice C, et al.: Br J Anaesth 1989, 63:667-670. 2. Saint-Maurice C, et al.: Br J Anaesth 1989, 63:667-670. References P431 Intravenous anesthesia with S-(+)-ketamine for ‘on-pump’ coronary artery bypass surgery: hemodynamic profile and effect on troponin T levels Results The maximal pain intensity was significantly higher on POD 1 and 2 (3.7 ± 2 and 3.9 ± 1.9, respectively) and lower on POD 3 (3.2 ± 1.5). The order of overall pain scores among activities (P < 0.001) from highest to lowest was coughing, moving or turning in bed, getting up, deep breathing or using the incentive spirometer, and resting. After chest tubes were discontinued, patients had lower pain levels at rest (P = 0.01), with coughing (P = 0.05). Age and sex was found to have an impact on pain intensity, with patients <60 years old and male patients having a higher pain intensity than older patients on POD 2 (4.7 ± 2.0 vs 3.2 ± 2.4, P = 0.02 and 4.5 ± 2.3 vs 2.9 ± 2.2, respectively). C Neuhaeuser1, V Preiss1, M Mueller1, S Scholz1, M Kwapizs1, I Welters2 C Neuhaeuser1, V Preiss1, M Mueller1, S Scholz1, M Kwapizs1, I Welters2 1University Hospital, Giessen, Germany; 2University of Liverpool, School of Clinical Science, Liverpool, UK Critical Care 2007, 11(Suppl 2):P431 (doi: 10.1186/cc5591) 1University Hospital, Giessen, Germany; 2University of Liverpool, School of Clinical Science, Liverpool, UK Critical Care 2007, 11(Suppl 2):P431 (doi: 10.1186/cc5591) Introduction In patients with ischemic coronary artery disease the ‘sympathomimetic’ effects of ketamine can cause myocardial damage. However, the S-isomer of ketamine may have various advantages. We studied the cardiovascular stability and safety of intravenous anesthesia with S-(+)-ketamine for coronary artery bypass graft surgery (CABGS). Introduction In patients with ischemic coronary artery disease the ‘sympathomimetic’ effects of ketamine can cause myocardial damage. However, the S-isomer of ketamine may have various advantages. We studied the cardiovascular stability and safety of intravenous anesthesia with S-(+)-ketamine for coronary artery bypass graft surgery (CABGS). Conclusions Pain relief is an important outcome of care. A comprehensive, individualized assessment of pain that incorporates activity levels is necessary to promote satisfactory management of pain. We recommend the use of remifentanil infusion for postoperative pain relief in suitable cardiac surgery patients. Methods After approval of the local ethics committee and written informed consent, 315 patients scheduled for elective ‘on-pump’ CABGS were enrolled in the study. Patients were randomly allocated to three anesthetic protocols: sufentanil–sevofluorane– propofol (SSP), sufentanil–propofol (SP), and S-(+)-ketamine– midazolam–propofol (KMP). P429 Results Stimulation with TNFα increased the percentage of DOR- expressing cells significantly from 2.1% to 12.8% positive cells after 6 hours. After 12 hours of stimulation 28.6%, and after 24 hours even 68.1%, of neutrophils expressed DOR. The MFI increased during TNFα stimulation from 47.6 ± 15.7 to 254.8 ± 110 after 6 hours, staying levelled at this height. After 6 hours of stimulation, the MFI for KOR reached a maximum, rising from 59.5 ± 19.4 to 513.9 ± 162. During TNFα stimulation, the percentage of positive cells increased from 5.4 to 65.0% after 24 hours (17.5% at 6 hours). Fourteen per cent of neutrophils expressed MOR after 6 hours (initially 5.4%) and up to 57.2% after 24 hours. The MOR MFI was measured at 43.4 ± 16.3 to 410 ± 263.6 6 hours after stimulation with TNFα. Available online http://ccforum.com/supplements/11/S2 2005. Five casualty cards were picked randomly every day from May 2005. The assessment and management of pain in each case was recorded. immunocyte activity. These effects are mediated by opioid receptors (OR) on peripheral white blood cells that can be detected and quantified by flow cytometry. We investigated OR expression on neutrophils using polyclonal antibodies against δ-opioid, κ-opioid and µ-opioid receptors (DOR, KOR, MOR) to assess spontaneous and TNFα-induced OR expression on neutrophils. immunocyte activity. These effects are mediated by opioid receptors (OR) on peripheral white blood cells that can be detected and quantified by flow cytometry. We investigated OR expression on neutrophils using polyclonal antibodies against δ-opioid, κ-opioid and µ-opioid receptors (DOR, KOR, MOR) to assess spontaneous and TNFα-induced OR expression on neutrophils. Results There were 155 patients in each month. In January, none of the patients were assessed for the severity of their pain; 34 patients received analgesia, of which 15 received weight-based and 19 received age-based analgesia. In May, 84 patients were assessed for the severity of their pain with the Alder Hey triage pain score; 63 received weight-based and two received age-based analgesia. The rest had no pain. Methods After approval by the local ethics committee and informed consent, 100 µl whole blood samples from 11 healthy volunteers (EDTA served as anticoagulant) was incubated with 10 µl TNF-α (100 ng/ml) for 3, 6, 12 and 24 hours. Samples were washed and incubated with 5 µl fluorescein-isothiocynate (FITC)- labelled polyclonal antibodies against human MOR, KOR and DOR. Rabbit IgG antibodies served as a negative control. After red cell lysis, flow cytometry was performed to quantify OR expression using live gating on neutrophils. The percentage of positive cells as well as mean fluorescent intensities (MFIs) were determined. Conclusion The Alder Hey triage pain score should be introduced in A&E as it serves as an effective means of assessing pain in children of all age groups. Analgesia should be prescribed based on the weight of the children. P431 Standard invasive hemodynamic monitoring was performed using a pulmonary artery catheter and hemodynamic variables were reported. Measurements were taken after induction of anesthesia, after weaning from cardiopulmonary bypass, and 6 hours postoperatively. Serial plasma troponin T levels were taken: before induction of anesthesia, after surgery, and 6 and 24 hours postoperatively. All cardiovascular adverse events were recorded (such as electrocardiographic signs of ischemia, myocardial infarction, 28-day mortality). Pain after cardiac surgery A Kianfar1, K Shadvar1, A Mahoori2, R Azarfarin1 1Madani Heart Center, Tabriz, Israel; 2Cardiac Anesthesia, Urumie, Israel Critical Care 2007 11(Suppl 2):P429 (doi: 10 1186/cc5589) Critical Care 2007, 11(Suppl 2):P429 (doi: 10.1186/cc5589) Critical Care 2007, 11(Suppl 2):P429 (doi: 10.1186/cc5589) Background Acute pain is common after cardiac surgery and can keep patients from participating in activities that prevent postoperative complications especially respiratory complications. Accurate assess- ment and understanding of pain are vital for providing satisfactory pain control and optimizing recovery. This study was performed to find the location, distribution, and intensity of pain in a sample of adult cardiac surgery patients during their postoperative ICU stay. Conclusion Our results display that stimulation of whole blood with TNFα amplifies OR expression of all subtypes significantly on neutrophils. We suggest further studies to clarify the specific actions of opioids and their receptors in health and acute inflammation. Methods In a prospective study, pain location, distribution (number of pain areas per patient), and intensity (0–10 numerical rating scale) were documented on 250 consecutive adult patients on the first, second and third postoperative day (POD). Patient characteristics (age, sex, size, and body mass index) were analyzed for their impact on pain intensity. There were 140 male and 110 female patients, with a mean ± SD age of 65.7 ± 13.5 years. References Methods A retrospective study. Five casualty cards with soft tissue injury and fractures in children under 16 years old were picked randomly every day from January 2005. The assessment and management of pain was recorded in each case. A validated pain score tool – Alder Hey triage pain score – was introduced April S170 S170 Available online http://ccforum.com/supplements/11/S2 P433 P433 Results Groups (SSP: n = 106; SP: n = 108, KMP: n = 101) did not differ in preoperative data (for example, biometry, cardiac and coronary profile and risk). Intraoperative management was comparable among groups. Tropinin T levels were rather lower in the KMP group, but did not differ significantly between groups at 24 hours after aortic unclamping. Cardiovascular adverse events showed the same low incidence in all groups. Hemodynamic data were comparable; however, the heart rate (HR) and mean arterial pressure (MAP) after induction were significantly higher in the KMP group (HR: 59 ± 11 vs 63 ± 32 vs 66 ± 13 beats/min (P < 0.01); MAP: 74 ± 12 vs 81 ± 16 vs 83 ± 16 mmHg (P < 0.01)). P432 Computer management systems and protocols in intensive care units: do we have any benefit? Table 1 (abstract P433) Methods A Medline search from 1996 to 2006 with the following key words was performed: critical care or intensive care, and protocol, and data management system or computer management system or computerized documentation. Results The search revealed 21 potential articles. The language was English in 18 of the articles, two in German and one in Japanese. Of those 21, 10 articles were not studying CMS/P. Of those 11 that fulfilled the criteria, computer management systems were studied in four articles and treatment protocols in 11 articles. The combination of ICU treatment protocol and computer manage- ment system was studied in four of the 21 articles. Conclusion Daily FAST-HUG review on ICU rounds, with aggressive oral care, an early extubation strategy, and aggressive infection control practices, decreases VAP rates. P430 Opioid receptor expression on neutrophils: effect of tumour necrosis factor alpha treatment Opioid receptor expression on neutrophils: effect of tumour necrosis factor alpha treatment A Schmidt1, I Welters2 1University of Giessen, Germany; 2Academic Unit of Critical Care Medicine, Liverpool, UK Critical Care 2007, 11(Suppl 2):P430 (doi: 10.1186/cc5590) Introduction Opioids and endogenous opioid peptides possess immunomodulating properties and are involved in the regulation of S171 S171 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Decreasing the incidence of ventilator-associated pneumonia using the FAST-HUG evaluation T Papadimos, S Hensley, J Duggan University of Toledo College of Medicine, Toledo, OH, USA Critical Care 2007, 11(Suppl 2):P433 (doi: 10.1186/cc5593) T Papadimos, S Hensley, J Duggan Introduction Ventilator-associated pneumonia (VAP) is a leading cause of morbidity and mortality in critically ill patients. We implemented a performance improvement project over 2 years to reduce VAP incidence in the medical ICU (MICU) and surgical ICU (SICU). Conclusion In our study, KMP anesthesia was safe to use for CABGS. In comparison with SSP and SP anesthesia, no significant rise in troponin T as a marker of myocardial damage was observed. All three regimens resulted in stable hemodynamics. However, the use of S-(+)-ketamine as an induction agent in patients with coronary artery disease may be limited due to its sympathomimetic effects leading to raised HR and MAP, even if supplemented by midazolam or propofol. Methods From 1 January 2004 to 31 December 2005 a prospective intervention was undertaken. Results were compared with historic controls (2003). In year 1 we introduced aggressive oral care using chlorhexidine mouthwash, an early extubation strategy, changing respiratory equipment only when visibly soiled or malfunctioning, and aggressive enforcement of hand-washing and barrier protection methods. At the end of year 1 we augmented the project with the addition of the FAST-HUG (feeding, analgesia, sedation, thromboembolic prevention, head of bed elevation, ulcer prophylaxis, and glucose control) evaluation. During year 2 FAST-HUG was emphasized daily on patient rounds by the intensivists. The CDC VAP definition was used; the Friedman test and Wilcoxon signed ranks test were used for data analysis. Computer management systems and protocols in intensive care units: do we have any benefit? M Rantala, K Kaukonen, V Pettilä Helsinki University Hospital, Helsinki, Finland Critical Care 2007, 11(Suppl 2):P432 (doi: 10.1186/cc5592) Results The VAP rates in the MICU and SICU for the control period, 1 January–31 December 2003, were 13.41 and 19.37 VAPs/1,000 ventilator-days, respectively. The MICU VAP rate declined to 3.02 VAPs/1,000 ventilator-days and the SICU rate declined to 8.16 VAPs/1,000 ventilator-days over 2 years. The greatest declines occurred during year 2 (Table 1). Introduction Computer management systems and treatment protocols (CMS/P) have been recommended for their potential to improve patient safety and outcome. Computer management systems require substantial investments in the ICUs. In return, a high-quality, standardised ICU treatment with software-implemented protocols as well as decreased hand-written documentation has been aimed at. The objective of this study was to systematically review the literature on CMS/P to evaluate their impact on outcome benefit. Table 1 (abstract P433) 2003 2004 2005 P values MICU 13.41 10.14 3.02 NSa, <0.05b,c SICU 19.37 16.45 8.16 NSa, <0.05b,c NS, not significant. a2003/04. b2004/05. c2003/05. P434 Of those 11, three of the studies demonstrated that the implementation of a protocol to computer management system increases staff compliance to the protocol. The newer studies showed also that the costs were not increased by the computer- ised protocol. However, no definite benefit in patient survival or ICU length of stay could be demonstrated (11 of 21 studies). The combined absolute reduction rate in hospital mortality was 2% (95% CI 0–4%) in those four (19% of 21) studies. CMS/P increased the ICU length of stay 3.5 days (95% CI 1.6–5.4 days) and decreased the hospital length of stay 5.9 days (95% CI 1.0–10.8 days), in two different studies. P Brindley P Brindley University of Alberta/Capital Health, Edmonton, Canada Critical Care 2007, 11(Suppl 2):P435 (doi: 10.1186/cc5595) This abstract outlines the use of simulated critical care telephone calls into the education of trainees. We hope others may consider it for their centres. Introduction A significant amount of time is spent in an ICU for procedures and the care of critically ill patients. Introduction A significant amount of time is spent in an ICU for procedures and the care of critically ill patients. The Capital Health Region provides advanced healthcare for 2 million people, but spread over 9,800 km. We therefore rely heavily on transportation of critically ill patients to a single urban centre. In addition to geographic and climatic factors, bed pressures complicate how we triage, stabilize, transport and receive those patients. A major strategy is the ‘Critical-Care-Line’: a 24-hour telephone service with teleconference capabilities and contact numbers. However, experience suggests it takes practice to become proficient with its use. Methods We prospectively collected data regarding demo- graphics and time in seconds required for ICU procedures. Time was recorded as the total time (preparation and action, Time A′) and actual time (intervention only, Time B′). Results We investigated 60 patients (43 males) of mean age 53.6 ± 3.3 years, severity of illness APACHE II score = 16.5 ± 0.3, SAPS II = 46.4 ± 0.7 and mean ICU stay of 18.6 ± 2.9 days. The time required for ICU procedures is shown in Table 1. Conclusions A significant amount of time is spent in an ICU for certain procedures. The length of time required is related to complications, failures, physicians’ level of training, and presence of assistance. ICU staff personnel should be adequately trained to decrease time, complications and thus the ICU stay and costs. Given the importance of optimal communication, we arrange simulated calls. Senior trainees are paged during a normal workday by the Critical-Care-Line: just as they will be once in independent practice. The facilitator then assumes the role of a referring doctor in a small town. Peer-reviewed cases are used that include pertinent teaching points. Applicable staff at the teaching centre are briefed of this exercise and asked to act as they normally would. Reference 1. Royal College of Physicians and Surgeons of Canada, CanMEDS framework [http://rcpsc] 1. Royal College of Physicians and Surgeons of Canada, CanMEDS framework [http://rcpsc] 1. Royal College of Physicians and Surgeons of Canada, CanMEDS framework [http://rcpsc] P435 P436 Simulated critical care calls: a simple way to teach complex skills P Brindley University of Alberta/Capital Health, Edmonton, Canada Critical Care 2007, 11(Suppl 2):P435 (doi: 10.1186/cc5595) P Brindley For example, emergency physicians, internists, senior nurses and administrators are notified that they may be brought into the call, depending on whether the trainee decides to involve other services (for example, if he/she decides a patient requires further work-up before deciding upon ICU or if he/she decides to bring the patient to emergency if no ICU bed is currently available). All calls are recorded to aid debriefing. Required time for certain intensive care unit procedures P Myrianthefs1, G Intas1, M Pitsoli1, L Louizou1, A Gavala1, G Baltopoulos2 1KAT Hospital, Athens, Greece; 2General Hospital of Attiki ‘KAT’, Kifissia, Greece Critical Care 2007, 11(Suppl 2):P436 (doi: 10.1186/cc5596) Available online http://ccforum.com/supplements/11/S2 factors in sex, age, trauma or nontrauma, whether or not PMCT, cause of death and final diagnosis. We especially compared the two groups: PMCT(+) and PMCT(–). referring physicians, and deal with complex ethical decisions (for example, if a family wishes to override a patient’s previous wish; or how aggressively to treat the terminal patient for whom no prior discussions have occurred). It allows us to test the trainees’ knowledge, but more importantly we can determine how well that knowledge is applied in everyday practice. Results Seventy patients (55.1%) were men, and 57 (44.9%) were women. Autopsy was done in only three patients. The number of trauma cases was 21 (16.5%) and nontrauma was 106 (83.5%). PMCT was done in 20 patients (15.7%) and it was possible to decide the final diagnosis in 16 (80%). Among 20 patients, there were six trauma cases and we could diagnose the cause of death in all of them. On the other hand, PMCT was not done in 107 patients (84.3%) and we could estimate the cause of death in just 43 (40.2%). In Canada, the Royal College of Physician and Surgeons has decreed that trainees become not just medical experts, but also proficient communicators, collaborators, and managers [1]. These goals, while laudable, have been very difficult to capture without novel approaches such as the one outlined. This simple and cost- free addition to our training has been very well received. Initial success means it will now be expanded throughout acute care specialist training. Conclusions We must make more effort to decide the cause of death. Reliable death diagnosis could lead to more effective cardiopulmonary resuscitation. Our date obviously indicated that PMCT was a very effective and powerful method for death diagnosis, especially in trauma cases. Significance of postmortem computed tomography in death diagnosis: investigation of the characteristics in patients with cardiopulmonary arrest on arrival Significance of postmortem computed tomography in death diagnosis: investigation of the characteristics in patients with cardiopulmonary arrest on arrival Introduction Autopsy is a very useful method in analysis of the cause of death. However, the number of those actual enforce- ments of autopsy has been getting less and less recently. Now, autopsy imaging is very important as an alternative method to autopsy. We evaluated the characteristics in patients with cardio- pulmonary arrest on arrival and studied the usefulness of postmortem computed tomography (PMCT) in death diagnosis. Patients and methods We analyzed consecutive patients with cardiopulmonary arrest on arrival from October 1997 to November 2006. Total number of patients was 127. We studied the multiple Introduction Autopsy is a very useful method in analysis of the cause of death. However, the number of those actual enforce- ments of autopsy has been getting less and less recently. Now, autopsy imaging is very important as an alternative method to autopsy. We evaluated the characteristics in patients with cardio- pulmonary arrest on arrival and studied the usefulness of postmortem computed tomography (PMCT) in death diagnosis. Introduction Autopsy is a very useful method in analysis of the cause of death. However, the number of those actual enforce- ments of autopsy has been getting less and less recently. Now, autopsy imaging is very important as an alternative method to autopsy. We evaluated the characteristics in patients with cardio- pulmonary arrest on arrival and studied the usefulness of postmortem computed tomography (PMCT) in death diagnosis. Conclusion Our results could not confirm any definite benefit from computerised data management systems or treatment protocols regarding outcome. The ICU personnel adherence to treatment protocols seems to increase when implemented into the computerised data management systems. Further research on this topic is needed to justify the investments in computer management systems. Patients and methods We analyzed consecutive patients with cardiopulmonary arrest on arrival from October 1997 to November 2006. Total number of patients was 127. We studied the multiple S172 Available online http://ccforum.com/supplements/11/S2 Simulated critical care calls: a simple way to teach complex skills Simulated critical care calls: a simple way to teach complex skills P438 Robust regression methods for intensive care monitoring The ‘Aiddiag’ data-acquisition software is a standalone application adapted to patient data recording from the biomedical devices and caregiver’s inputs. It has a friendly designed user-interface touchscreen at the bedside and was adapted according to caregivers’ feedback. Data are also stored in a repository and a selective secondary extraction is possible. Online and offline analysis by the AI engine is allowed. Software had to consider time specifications and uses distributed computation to achieve high workload tasks. We complied to the French legal patient data management constraints. M Imhoff1, K Schettlinger2, R Fried2, U Gather2, S Siebig3, C Wrede3 1Ruhr-University Bochum, Germany; 2University of Dortmund, Germany; 3University Hospital Regensburg, Germany Critical Care 2007, 11(Suppl 2):P438 (doi: 10.1186/cc5598) Introduction Alarm generation of modern patient monitoring systems still predominantly relies on simple threshold methods. This leads to an unacceptably high rate of false positive alarms. Many false positive alarms are generated by measurement artefacts and measurement noise. One approach to address this problem is to alarm on the underlying signal (that is, the noise-free time series of the physiological variable), instead of the raw measurement. Results After 2 years, our system is fully deployed. It recorded more than 2,500 patient-hours over a 3-month period. Signal loss is less than 1%. Our tool allows recording of more than 40 digital signals, eight analogical signals sampled at a rate of 1 kHz, and caregiver comments and actions. CPU resources of the laptop are available for supplemental AI developments during data acquisition. Transfer of data to the repository is either a hotplug- automated process or delayed with 5 days of buffering in the laptop. Automated artefacts’ cleaning allows time-series analysis (GARCH method) to extract behavioural models after intensive computation. The AI engine is used for medical guideline implementation (that is, severe brain trauma care algorithms) and later comparison with caregiver’s behaviour. Remote use of our system is possible and schedulable, allowing other research teams to work on the data. Limitations have been detected during intensive calculation. Fine-tuning of the network will suppress these limitations. Methods Monitoring time series were simulated. Against these data four robust regression methods were evaluated: least trimmed squares (LTS), least median of squares (LMS), repeated median (RM), and deepest regression (DR). Moreover, online monitoring series from critically ill patients during multiparameter monitoring were also compared. P439 P439 ISIS program: a new tool for medical research at the bedside in critical care units H Mehdaoui1, B Sarrazin1, I El Zein1, L Allart2, C Vilhelm2, S Guerra2, D Zitouni2, M Lemdani2, R Valentino1, A Herbland1, P Ravaux2 1Fort De France University Hospital, Fort De France, Martinique; 2Lille 2 University, Lille, France Critical Care 2007, 11(Suppl 2):P439 (doi: 10.1186/cc5599) Results MD1 found clinically relevant events in 36%, and MD2 in 29% of all time series. In 16% of all cases both intensivists came to different classifications. In 10% even the direction of change was classified differently. MD2 classified 10% of all cases differently between the first and second analysis. Even if level changes and trends were treated as one universal pattern of change, intra-individual variability (MD2 first analysis vs MD2 second analysis) was still 5% and inter-individual variability (MD1 vs MD2, only unequivocal classifications) was 10%. Conclusion Although this study is small with only two observers who were investigated, it clearly shows that there is a significant intra-individual and inter-individual variability in the classification of monitoring events done by experienced clinicians. These findings are supported by studies into image analysis that also found high intra-individual and inter-individual variability. High inter-observer and intra-observer variability is a challenge for clinical studies into new alarm algorithms. Our findings also show a need for reliable classification methods. Introduction The goal of this program is to develop an experi- mental tool able to record, store and analyse data issued from critical care patients. Due to technical limitations and medical constraints, information systems able to manage such data flow are difficult to deploy. Introduction The goal of this program is to develop an experi- mental tool able to record, store and analyse data issued from critical care patients. Due to technical limitations and medical constraints, information systems able to manage such data flow are difficult to deploy. Methods Data recording is done through a laptop connected to the medical devices, allowing analogical and digital signal transmission through a high-speed network. Several servers are dedicated to specialised tasks: mass storage, model generation, artificial intelligence (AI), telecommunications, and security. A 3 Teraflops supercomputer is dedicated to intensive computation when necessary. Twenty applications are dedicated to elective tasks, most of them running using the Linux operating system. P437 Intra-observer and inter-observer variability of clinical annotations of monitoring data M Imhoff1, R Fried2, U Gather2, S Siebig3, C Wrede3 1Ruhr-University Bochum, Germany; 2University of Dortmund, Germany; 3University Hospital Regensburg, Germany Critical Care 2007, 11(Suppl 2):P437 (doi: 10.1186/cc5597) Intra-observer and inter-observer variability of clinical annotations of monitoring data Introduction In order to evaluate new methods for alarm genera- tion from monitoring data, a gold standard of alarm evaluation is Introduction In order to evaluate new methods for alarm genera- tion from monitoring data, a gold standard of alarm evaluation is Introduction In order to evaluate new methods for alarm genera- tion from monitoring data, a gold standard of alarm evaluation is This method allows us to ascertain how trainees ask focused histories, offer practical advice based upon the variable skill set of S173 Table 1 (abstract P436) Failure at first Number of Procedure n Time A′ Time B′ attempt (%) required efforts Central line placement 120 1,791 ± 52.6 1,023.6 ± 40.3 10.4 2.6 ± 0.3 Arterial line placement 251 491.4 ± 38.5 240.6 ± 26.8 30.4 2.3 ± 0.2 Tracheal tube change 78 910.1 ± 43.7 46.4 ± 4.4 5.5 1.4 ± 0.1 Tracheostomy change 96 565.2 ± 26.8 34.3 ± 2.5 7.1 1.1 ± 7.1 Transfer for CT 76 3,375.5 ± 174.5 1,912.1 ± 87.3 0.0 1.0 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Conclusion All four methods allow one to extract the underlying signal from physiological time series in a way that is robust against measurement artefacts and noise. However, there are significant differences between the methods. Overall, repeated median regression seems the best choice for intensive care monitoring since it is not only the most stable but also the fastest method. needed. Nearly all clinical studies into monitoring alarms used clinician judgement and annotation as the reference standard. We investigated the intra-observer and inter-observer variability between two intensivists in the classification of monitoring time series. Methods A total of 3,092 time series segments (heart rate and blood pressures) of 30 minutes each from six critically ill patients were presented to two experienced intensivists (MD1 and MD2) offline and were visually classified into clinically relevant patterns (no change, level shift, trend) by the physicians separately. One intensivist (MD2) repeated the classification 4 weeks after the first analysis on the same dataset. Inter-rater agreement in the triage of calls to a paediatric interhospital transfer service Inter-rater agreement in the triage of calls to a paediatric interhospital transfer service S Riphagen, M Alasnag, S Hanna, S Manna, M McDougall Guy’s and St Thomas’ Hospital, London, UK Critical Care 2007, 11(Suppl 2):P440 (doi: 10.1186/cc5600) M McDougall, S Riphagen, S Hanna, S Moganasundram, F Bickell, A Durward, I Murdoch Evelina Children’s Hospital @ Guy’s and St Thomas’ NHS Foundation Trust, London, UK Critical Care 2007, 11(Suppl 2):P441 (doi: 10.1186/cc5601) Introduction As a result of centralisation of PICU services in the United Kingdom, transfer of critically ill children has become common over the past decade. It is not uncommon to receive multiple retrieval requests simultaneously, thus a tool to prioritise the urgency of this would be beneficial. Our aim was to develop such a tool and assess its inter-rater repeatability. Introduction The South Thames Retrieval Service (STRS) is a specialised paediatric intensive care retrieval service, integrated into the Evelina Children’s Hospital, the lead centre in the South Thames Region, London. Over the last 5 years a number of initiatives have been adopted to reduce mobilisation times (the time from retrieval acceptance and activation to departure from the lead centre) and improve service delivery to surrounding district general hospitals (DGHs). The aim of this study was to evaluate whether these initiatives led to a reduction in mobilisation time between January 2002 and December 2006. Introduction The South Thames Retrieval Service (STRS) is a specialised paediatric intensive care retrieval service, integrated into the Evelina Children’s Hospital, the lead centre in the South Thames Region, London. Over the last 5 years a number of initiatives have been adopted to reduce mobilisation times (the time from retrieval acceptance and activation to departure from the lead centre) and improve service delivery to surrounding district general hospitals (DGHs). The aim of this study was to evaluate whether these initiatives led to a reduction in mobilisation time between January 2002 and December 2006. Methods The tool was developed by three senior medical staff of the South Thames Retrieval Service (operating from the PICU at Evelina Children’s Hospital, London with 1,000 calls per annum from 24 district general hospitals, resulting in 600 retrievals). A modified Delphi method was used, which comprised an iterative process including a literature review, knowledge of the underlying conditions and a review of retrievals performed by the service over the previous 7 years (n = 3,669). P440 P440 Figure 1 (abstract P440) Results A total of 2,761 retrievals (median age 12 months, 78% ventilated) were performed and included for analysis during the study period, 33 were excluded (missing mobilisation times (n = 30) or elective transfers (n = 3). Figure 1 shows the process introduced to improve mobilisation times with a dedicated onsite ambulance service in 2004. There was a significant reduction in Inter-rater agreement in the triage of calls to a paediatric interhospital transfer service Inter-rater agreement was assessed using the weighted kappa statistic, and was measured between various pairings of junior and senior medical staff (n = 28 combinations) on 50 retrieval episodes. Methods The STRS covers 24 DGHs within an 80 mile range serving a population of 1.6 million children in the South Thames region of Greater London. All calls to the service were logged on a detailed database. Retrieval requests for potential PICU patients were triaged and coordinated via a retrieval-specific telephone line. Once accepted, the onsite retrieval team was mobilised and dispatched via a dedicated ambulance to the DGH. Mobilisation includes assimilating and checking pre-packed equipment bags (ventilators, drugs, intubation kit, monitors, and so on) and organising a team of at least one retrieval nurse, doctor and ambulance driver. Details of each retrieval request to the STRS, including the time of the call, were captured on a database containing the patient demographic and clinical details. The interval between accepting the patient for retrieval and team departure from the unit was termed the ‘mobilisation time’ (minutes). Data were analysed over two time periods, before (n = 976 retrievals) and after 2004 (n = 1,785), coincident with a dedicated ambulance and driver on site. Nonparametric tests were used for continuous data (Kruskall–Wallis test or Mann–Whitney test) and the chi-squared test for categorical 2 x 2 comparisons. Results The final tool comprised five categories (three levels of severity each) allowing for a range of scores from 0 to 15 (Figure 1). Three levels of urgency were defined: semi-urgent (score <8), urgent (score 8–10), immediate (score >10). Overall the tool showed a good to very good strength of inter-rater agreement (kappa scores ranging from 0.65 to 0.88; Figure 2). There were no obvious differences between levels of staff seniority. Conclusion The score showed acceptable agreement, fullfilling the first step of validation. P438 Results LTS and LMS showed comparable behaviour, as did RM and DR. LMS and LTS provided only 20% efficiency, DR 61% and RM 70% (least squares regression = 100%). RM and DR had smaller standard deviations and smaller mean-squared errors than LMS and LTS under different noise distributions (standard deviation of online estimates based on sliding windows of size n = 21 for simulated standard normal errors: LMS: 0.875, LTS: 0.887, RM: 0.500, DR: 0.533). Analyses with clinical monitoring data also showed that LMS and LTS preserve sudden level shifts but are unstable and perform poorly with trend changes; RM and DR blur shifts but yield more stable estimations. Conclusion ISIS is the first program to achieve an easy-to-use recording tool able to build a very large medical repository. Data analysis methods and AI-controlled automated complex medical guidelines are under evaluation. S174 Available online http://ccforum.com/supplements/11/S2 P443 The use of a track and trigger system on general medical wards M Lawson, A Stone, D King, A Davison Southend University Hospital, Southend, UK Critical Care 2007, 11(Suppl 2):P443 (doi: 10.1186/cc5603) The use of a track and trigger system on general medical wards M Lawson, A Stone, D King, A Davison Southend University Hospital, Southend, UK Critical Care 2007, 11(Suppl 2):P443 (doi: 10.1186/cc5603) The use of a track and trigger system on general medical wards Median retrieval mobilisation times. M Lawson, A Stone, D King, A Davison Southend University Hospital, Southend, UK Critical Care 2007, 11(Suppl 2):P443 (doi: 10.1186/cc5603) mobilisation time from 2002 to 2006 from 55 minutes (IQR 35–80) to 30 minutes (IQR 25–50), P < 0.0001 (Kruskall–Wallis) (Figure 2). When comparing pre-2004 and post-2004 time periods, the median mobilisation time was significantly lower after 2004 with a fall from 45 minutes (IQR 30–70) to 35 minutes (IQR 27–55). There was also a significant increase in the incidence of sub-30-minute mobilisation times, which almost doubled after 2004 with the availability of an onsite dedicated ambulance service (14.3% to 25.9%, P < 0.0001). Introduction Many groups have advocated identification of critically ill medical patients by abnormal or deteriorating physiological parameters. In Southend Hospital a track and trigger system has been used since 2005 to alert nurses to abnormal physiological parameters in order to trigger urgent medical review of the unwell patient. It is recognised that the respiratory rate is a particularly useful predictor of significant deterioration and should be measured with every set of observations. This audit aimed to assess the use of the track and trigger system on the medical wards and ensure that deteriorating critically ill patients are promptly reviewed. Conclusion There has been a significant decrease in the mobilisation time of the STRS over the last 5 years. Although the presence of an onsite ambulance service in 2004 had a significant impact on reducing retrieval mobilisation times, a number of other factors and initiatives contributed to steadily reducing mobilisation times over the study period. Methods Patient observation charts were reviewed for a specified 24-hour period. Data were gathered on the frequency and type of observations taken. For patients who met criteria to trigger a review, further data were abstracted about the nature of the deterioration and the promptness of the review. Figure 1 (abstract P441) S175 Processes introduced to improve mobilisation times. S Processes introduced to improve mobilisation times. Figure 2 (abstract P440) Figure 2 (abstract P440) Figure 2 (abstract P440) S175 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicine Figure 2 (abstract P441) Median retrieval mobilisation times. Figure 2 (abstract P441) Median retrieval mobilisation times. Table 1 (abstract P442) Penetrating trauma Private transport Ambulance Alive 98.8% (n = 254) 95.6% (n = 527) Dead 1.2% (n = 3) 4.4% (n = 24) Table 1 (abstract P442) Conclusion The use of ambulance transportation is associated with a 3.7-fold increase in mortality following penetrating injury. This may be related to longer times in the field resulting in delay to definitive care in hospital. P442 Results One hundred and sixty patient-days of observations were evaluated over seven medical wards. Twenty-nine patients met the trigger criteria and in 16 cases this represented a deterioration. Doctors were called in two cases. Observations were recorded with different frequency on different wards. One ward managed to record the respiratory rate with every set of observations. Ambulance transport is associated with a higher mortality than private transport following major penetrating trauma in a semi-urban environment E Dickson, D Van Niekerk, S Robertson, J Goosen, F Plani, K Boffard Johannesburg Hospital Trauma Unit and University of the Witwatersrand, Johannesburg, South Africa Critical Care 2007, 11(Suppl 2):P442 (doi: 10.1186/cc5602) Conclusions Documented deteriorations in physiological observations did not trigger medical review. This may be a communication failure or failure to recognise recorded observations as abnormal. For this process to work well relevant observations must be recorded regularly and accurately. The respiratory rate was not consistently recorded between wards and the frequency of measurement of observations was variable. Further education and training is needed to improve recording of the respiratory rate and work needs to be done to establish why doctors were not called appropriately. Concerns about the volume of work generated by the system are unfounded. A positive predictive value of 55% is acceptable and 29 ‘triggers’ in a 24-hour period are manageable. Aims The use of private transportation has been associated with improved outcomes in urban trauma patients. The need for patient stabilization at the scene needs to be balanced with the need for early operative intervention, and therefore the need for rapid transportation to hospital. Our aim was to assess the relationship between the mode of transport to hospital and outcome in a semi- urban trauma environment. Methods Data were collected prospectively on 1,396 patients admitted to a Level 1 South African trauma unit over a 1-year period. The Revised Trauma Score was used to assess injury severity and physiological derangement at the time of admission, and to allow comparison between the groups. Mortality was defined as death within 30 days. P444 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 was commissioned by the Ministry of Health and Long-term Care to facilitate the improvement of inhospital emergency preparedness through a System-Level Training Initiative. Objectives for the program were to reduce mortality and improve efficiency of ICU resource use through early identification of patients at risk of deterioration and the provision of rapid resuscitation to abort avoidable ICU admissions. The program was designed to train nonphysician responders (primarily nurses and respiratory therapists) supported by remote physician oversight, especially in centres where ICU-trained physicians were not available. the ward, the presence of a CCOS was associated with significant reductions in: the proportion of admissions receiving cardio- pulmonary resuscitation during the 24 hours prior to admission (odds ratio 0.84, 95% confidence interval 0.73–0.96); the proportion of admissions between 22:00 and 06:59 (0.91, 0.84–0.97); and the mean ICNARC physiology score (absolute reduction 1.2, 0.3–2.1). No significant effects of CCOS on outcomes including hospital mortality and readmission to critical care were identified for patients discharged to the ward. Interpretation The results of this study were mixed. While some differences in the characteristics of patients admitted to critical care units were found to be associated with the introduction of CCOS, there was no evidence for an impact on the outcomes of patients discharged from critical care. It was not possible to identify any clear characteristics for an optimal CCOS. the ward, the presence of a CCOS was associated with significant reductions in: the proportion of admissions receiving cardio- pulmonary resuscitation during the 24 hours prior to admission (odds ratio 0.84, 95% confidence interval 0.73–0.96); the proportion of admissions between 22:00 and 06:59 (0.91, 0.84–0.97); and the mean ICNARC physiology score (absolute reduction 1.2, 0.3–2.1). No significant effects of CCOS on outcomes including hospital mortality and readmission to critical care were identified for patients discharged to the ward. Interpretation The results of this study were mixed. While some differences in the characteristics of patients admitted to critical care units were found to be associated with the introduction of CCOS, there was no evidence for an impact on the outcomes of patients discharged from critical care. It was not possible to identify any clear characteristics for an optimal CCOS. Methods Following an educational needs assessment of learners, a multicomponent critical care response team (CCRT) training course was developed. M Seubert M Seubert Academic Medical Center, Amsterdam, The Netherlands Critical Care 2007, 11(Suppl 2):P446 (doi: 10.1186/cc5606) Academic Medical Center, Amsterdam, The Netherlands Critical Care 2007, 11(Suppl 2):P446 (doi: 10.1186/cc5606) Introduction Blood groups may be related to differences in inflammatory responses [1]. We looked at blood group as a risk factor for ICU mortality in general and for patients with sepsis. Introduction Blood groups may be related to differences in inflammatory responses [1]. We looked at blood group as a risk factor for ICU mortality in general and for patients with sepsis. Methods Data were retrospectively collected from all 11,553 patients that were admitted from 1997 to 2005 to our medical/ surgical ICU. Methods Data were retrospectively collected from all 11,553 patients that were admitted from 1997 to 2005 to our medical/ surgical ICU. Conclusions It has been demonstrated that unmet needs in critical care education and training for allied healthcare professionals can be identified and corrected through the development and implementation of a multidisciplinary course designed to facilitate creation of CCRTs in the Province of Ontario. Evaluation of the effectiveness of these teams is ongoing. Results ICU mortality and SAPS II score for different blood groups are shown in Table 1. P values are given for the difference between blood groups A and O. No differences were found for age, gender, and reason for admission. No influence of rhesus blood group type was seen on mortality. Available online http://ccforum.com/supplements/11/S2 The 2-day course consisted of a series of small group, interactive, case-based seminars, high-fidelity simulation training, and the publication of a CCRT Provider Manual and Quick Reference Cards. A database for monitoring the effectiveness and impact of the CCRTs was also developed. P446 Results Beginning in October 2005, 24 CCRT physician instructors were trained in one of two streams: (i) simulator instructors with skills in constructive feedback and assessment of crisis management skills; (ii) instructors who further refined the case-based seminars and edited the Quick Reference Cards. Acquisition of equipment, liaisons with participating hospitals and creation of the CCRT database were completed in the spring of 2006. Since June 2006, 12 CCRT courses have been run, and 263 participants have been trained as CCRT Providers (87% nurses, and 13% respiratory therapists). Local hospital implementation and preceptored programs occurred over a 12-week period before CCRTs we made available full time (24/7). Influence of ABO blood group polymorphism on mortality in intensive care unit patients Reference Reference 1. Garratty G: Transfusion Med Rev 2000, 14:291. Reference 1. Garratty G: Transfusion Med Rev 2000, 14:291. e e e ce 1. Garratty G: Transfusion Med Rev 2000, 14:291. 1. Garratty G: Transfusion Med Rev 2000, 14:291. P445 Individual patient- level data were collapsed into monthly time series for each unit (panel data). Population-averaged panel-data models were fitted using a generalised estimating equation approach. Various outcomes reflecting the stated aims of CCOS were considered for three groups of admissions: all admissions to the unit; admissions from the ward; and unit survivors discharged to the ward. The primary exposure variable was the presence of a formal CCOS with secondary exposures of CCOS activities, coverage and staffing, identified from the survey data. P445 Table 1 (abstract P446) ABO blood group A B AB O P value All patients n = 4,787 n = 1,168 n = 479 n = 5,119 ICU death (%) 9.5 10.2 10.9 11.2 <0.01 SAPS II 32 ± 16 33 ± 17 34 ± 18 33 ± 17 NS Severe sepsis n = 265 n = 73 n = 34 n = 318 ICU death (%) 24.9 28.8 26.5 32.4 0.05 SAPS II 49 ± 18 49 ± 18 54 ± 19 51 ± 18 NS Multicentre evaluation of the impact of the introduction of outreach services in the United Kingdom H Gao1, D Harrison1, G Parry2, K Daly3, C Subbe4, K Rowan1 1ICNARC, London, UK; 2Children’s Hospital Boston, MA, USA; 3St Thomas’ Hospital, London, UK; 4Wrexham Maelor Hospital, Wrexham, UK Critical Care 2007, 11(Suppl 2):P445 (doi: 10.1186/cc5605) Background Critical care outreach services (CCOS) have been introduced in the United Kingdom with aims to: avert or ensure timely admission to critical care; enable discharge from critical care; and share skills with ward staff. We aimed to assess the impact of the introduction of CCOS at the critical care unit level, as characterised by the case mix, outcome and activity of critical care unit admissions. Methods An interrupted time-series analysis was carried out using data from 108 units participating in the Case Mix Programme that had completed a survey on CCOS provision. Individual patient- level data were collapsed into monthly time series for each unit (panel data). Population-averaged panel-data models were fitted using a generalised estimating equation approach. Various outcomes reflecting the stated aims of CCOS were considered for three groups of admissions: all admissions to the unit; admissions from the ward; and unit survivors discharged to the ward. The primary exposure variable was the presence of a formal CCOS with secondary exposures of CCOS activities, coverage and staffing, identified from the survey data. R lt Of 108 it i th l i 79 (73%) h d f l Conclusion Blood group O is associated with a higher ICU mortality rate than blood group A. The relative risk increase for ICU mortality was 18% for all patients and 30% for patients with severe sepsis. y y Methods An interrupted time-series analysis was carried out using data from 108 units participating in the Case Mix Programme that had completed a survey on CCOS provision. P444 Design and implementation of needs-specific critical care response teams R Hodder1, A Fox-Robichaud2, R Wax3, P Cardinal1, S Reynolds3 1University of Ottawa, Canada; 2McMaster University, Hamilton, Canada; 3University of Toronto, Canada Critical Care 2007, 11(Suppl 2):P444 (doi: 10.1186/cc5604) Results The mortality in the blunt trauma patients (n = 527) was higher in the ambulance transport group, but this was not statistically significant. However, the mortality in the penetrating trauma patients (n = 808) was significantly higher in the ambu- lance transport group (P = 0.020, chi-square; Table 1) despite similar Revised Trauma Scores (Table 1). Introduction Following the severe acute respiratory syndrome epidemic in Ontario Canada, the Canadian Resuscitation Institute S176 Available online http://ccforum.com/supplements/11/S2 P447 The present findings have important implications in the understanding of the role of DEFB1 in the pathophysiology of severe sepsis, and DEFB1 genomic variations may offer a new means of risk stratification for patients with severe sepsis. of quantification of in vivo gene expression with QRT-PCR providing more accurate and sensitive data when compared with prior ELISA-based assays. Indeed, the extrapolation of functionality from in vitro functional genetic tests after lipopolysaccharide stimu- lation may be of questionable value. We conclude that genotypic analysis does have a place in risk stratification in sepsis and that genetic variants at positions –863 and –308, or sites in linkage disequilibrium with these variants, may influence TNFα production. P447 P447 P447 Contribution of genomic variations within human β- defensin 1 to incidence and outcome of severe sepsis X Fang, C Lv, Q Chen, L Huang Zhejiang University, Hangzhou, China Critical Care 2007, 11(Suppl 2):P447 (doi: 10.1186/cc5607) Contribution of genomic variations within human β- defensin 1 to incidence and outcome of severe sepsis Contribution of genomic variations within human β- defensin 1 to incidence and outcome of severe sepsis X Fang, C Lv, Q Chen, L Huang Zhejiang University, Hangzhou, China Critical Care 2007, 11(Suppl 2):P447 (doi: 10.1186/cc5607) X Fang, C Lv, Q Chen, L Huang Zhejiang University, Hangzhou, China Critical Care 2007, 11(Suppl 2):P447 (doi: 10.1186/cc5607) S177 Sepsis, a systemic inflammatory response to infection, is a common clinical syndrome in the ICU. Human β-defensin 1 (DEFB1) is a Results Of 108 units in the analysis, 79 (73%) had a formal CCOS introduced between 1996 and 2004. For admissions from Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin multifunctional mediator in infection and inflammation, which has been largely explored in ex vivo studies. The lack of fully representative genetic animal models increases the importance of analyzing the impact of defensin gene polymorphisms on the courses of infectious and inflammatory diseases such as sepsis. This study was designed to investigate whether DEFB1 genomic variations are associated with incidence and outcome of severe sepsis. Six reported polymorphisms were detected in 211 patients with severe sepsis and 157 control individuals using diverse analytic methods. Linkage disequilibrium (LD), haplotype frequen- cy, and statistical power for this association study were analyzed. The –44G-allele and –44G-allele carrying genotypes were significantly associated with incidence and outcome of severe sepsis. There was enough statistical power (1 – β > 0.8 at type I level of 0.05) to demonstrate a significant contribution of the –44G allele to severe sepsis. The –20G allele and GG genotype were associated with susceptibility to severe sepsis, while the –1816G- allele and –1816G-allele carrying genotypes influenced the outcome of severe sepsis. SNPs –20A/G, –44C/G and –52A/G were in strong LD. Haplotype –20A/–44C/–52G showed a protective role against severe sepsis, whereas haplotype –20G/–44G/–52G served as a risk factor for fatal outcome of severe sepsis. P448 P448 TNFα promoter single nucleotide polymorphisms may influence gene expression in patients with severe sepsis M Odwyer1, M White1, R McManus2, T Ryan1 1St James’s Hospital, Dublin, Ireland; 2Trinity College, Dublin, Ireland Critical Care 2007, 11(Suppl 2):P448 (doi: 10.1186/cc5608) ill systemic inflammatory response syndrome (SIRS) patients. Methods Uninfected, critically ill trauma patients with SIRS were evaluated daily for sepsis. Patients were divided into two groups: pre-septic = SIRS patients who developed sepsis, and uninfected SIRS = SIRS patients remaining uninfected. Plasma samples and whole blood (PAXgene) obtained at study entry and daily for 3 days prior to sepsis were analyzed for differential gene expression between groups (Affymetrix Hg_U133 2.0 plus microarray, false discovery rate < 0.5%, P < 0.005) and quantitative plasma protein TNF and IL-1 levels (Immunoassay, Luminex™, elevated if > 3 SD above the mean for normals). Gene expression data are the median fold change between groups (uP = pre-septic > uninfected). P449 IL-1/tumor necrosis factor receptor gene expression characterizes sepsis in critically ill systemic inflammatory response syndrome patients IL-1/tumor necrosis factor receptor gene expression characterizes sepsis in critically ill systemic inflammatory response syndrome patients M Lissauer1, S Johnson1, C Feild1, C Whiteford2, W Nussbaumer2, T Scalea1 1University of Maryland Medical Center, R Adams Cowley Shock Trauma Center, Baltimore, MD, USA; 2BD Diagnostics, Sparks, MD, USA Critical Care 2007, 11(Suppl 2):P449 (doi: 10.1186/cc5609) Introduction The classic response to isolated endotoxin challenge entails secretion of IL-1 and TNFα. The purpose of this study was to longitudinally characterize the cytokine response to sepsis in critically ill systemic inflammatory response syndrome (SIRS) patients. Methods Uninfected, critically ill trauma patients with SIRS were evaluated daily for sepsis. Patients were divided into two groups: pre-septic = SIRS patients who developed sepsis, and uninfected SIRS = SIRS patients remaining uninfected. Plasma samples and whole blood (PAXgene) obtained at study entry and daily for 3 days prior to sepsis were analyzed for differential gene expression between groups (Affymetrix Hg_U133 2.0 plus microarray, false discovery rate < 0.5%, P < 0.005) and quantitative plasma protein TNF and IL-1 levels (Immunoassay, Luminex™, elevated if > 3 SD above the mean for normals). Gene expression data are the median fold change between groups (uP = pre-septic > uninfected). Results Gene expression on 90 patients and protein measure- ments on 142 patients were available. Protein levels of both subtypes of TNF and IL-1 were not elevated at any time point in either group. IL-1α was noted to have differential gene expression 24 hours before sepsis. No differences were noted in gene expression for TNFα, TNFβ, or IL-1β. Differential gene expression for only two TNF family members (TNFSF10 and TNFSF13b) was noted. However, differential gene expression for TNF and IL-1 receptors and IL-1 receptor antagonist was prominent (Table 1). Introduction The classic response to isolated endotoxin challenge entails secretion of IL-1 and TNFα. The purpose of this study was to longitudinally characterize the cytokine response to sepsis in critically ill systemic inflammatory response syndrome (SIRS) patients. Introduction The classic response to isolated endotoxin challenge entails secretion of IL-1 and TNFα. The purpose of this study was to longitudinally characterize the cytokine response to sepsis in critically ill systemic inflammatory response syndrome (SIRS) patients. TNFα promoter single nucleotide polymorphisms may influence gene expression in patients with severe sepsis TNFα promoter single nucleotide polymorphisms may influence gene expression in patients with severe sepsis M Odwyer1, M White1, R McManus2, T Ryan1 1St James’s Hospital, Dublin, Ireland; 2Trinity College, Dublin, Ireland Critical Care 2007, 11(Suppl 2):P448 (doi: 10.1186/cc5608) Introduction We examined the association of TNFα promoter single nucleotide polymorphisms and haplotypes with gene expression in terms of mRNA levels and with outcome in a cohort of patients with severe sepsis. Results Gene expression on 90 patients and protein measure- ments on 142 patients were available. Protein levels of both subtypes of TNF and IL-1 were not elevated at any time point in either group. IL-1α was noted to have differential gene expression 24 hours before sepsis. No differences were noted in gene expression for TNFα, TNFβ, or IL-1β. Differential gene expression for only two TNF family members (TNFSF10 and TNFSF13b) was noted. However, differential gene expression for TNF and IL-1 receptors and IL-1 receptor antagonist was prominent (Table 1). Methods Sixty-two Irish Caucasian patients presenting with severe sepsis were enrolled. Blood sampling was carried out on day 1 and on day 7. Mononuclear cells were isolated and TNFα mRNA quantified using the technique of quantitative real-time polymerase chain reaction (QRT-PCR). DNA was extracted and assayed for four TNFα promoter polymorphisms. Haplotypes were inferred using PHASE software. Results Twenty-seven patients died. Patients carrying an A allele at position –863 produced more TNFα mRNA on day 1 than C homozygotes (P = 0.037). There was a trend for patients homozygous for the G allele at position –308 to produce more TNFα mRNA on day 1 than those carrying an A allele (P = 0.059). Carrier status for haplotype 1 (with A at position –863 and G at position –308) was associated with greater TNFα mRNA levels on day 1 (P = 0.0374). Carrier status for haplotype 4 (with C at position –863 and A at position –308) was associated with a nonsignificant decrease in TNFα mRNA levels on day 1 (P = 0.059). When directly compared, haplotype 1 was associated with significantly greater levels of TNFα mRNA than with haplotype 4 on day 1 (P = 0.02). Patients homozygous for the A allele at position –308 were more likely to succumb to severe sepsis than those carrying the G allele (P = 0.01). A novel score based on age and cardiac biomarkers predicts outcomes in severe sepsis and septic shock predicts outcomes in severe sepsis and septic shock A Turley, A Thornley, A Roberts, M Johnson, M de Belder, J Gedney The James Cook University Hospital, Middlesbrough, UK Critical Care 2007, 11(Suppl 2):P450 (doi: 10.1186/cc5610) F Leitch1, E Dickson1, A McBain1, S Robertson2, D O’Reilly1, C Imrie1 1Glasgow Royal Infirmary, Glasgow, UK; 2Johannesburg Hospital, Johannesburg, South Africa Critical Care 2007, 11(Suppl 2):P451 (doi: 10.1186/cc5611) 1Glasgow Royal Infirmary, Glasgow, UK; 2Johannesburg Hospital, Johannesburg, South Africa Critical Care 2007, 11(Suppl 2):P451 (doi: 10.1186/cc5611) Background Myocardial dysfunction is common among critically ill septic patients. Elevated levels of cardiac biomarkers are predictors of mortality in acute coronary syndrome and in unselected critically ill patients. Our aim was to evaluate the role of the cardiac markers NT-proBNP, Troponin T (TnT) and myoglobin as predictors of inhospital and 6-month all-cause mortality in patients admitted to a general adult ICU with severe sepsis/septic shock. Introduction Early identification of critically ill surgical patients who are not fully resuscitated improves outcome. Current markers of clinically occult hypoperfusion, such as lactate, have serious limi- tations. Increased oxidative stress as a consequence of inadequate cellular respiration results in elevated levels of unmeasured anions. We evaluated these anions as a novel marker of outcome. Methods We prospectively evaluated 109 consecutive patients admitted to a surgical high-dependency unit (HDU). Regional Ethics Committee approval was obtained. Serum electrolytes, albumin, phosphate and lactate were measured on admission and days 1 and 2. We derived the calculated ion gap (CIG) using our simplified modification of the Stewart–Figge equations. Methods Serial plasma samples were taken for five sequential days on all patients admitted with severe sepsis/septic shock. Samples were analysed for NT-proBNP, TnT and myoglobin. Results Samples were analysed on 49 patients. Elevated myoglobin was the only predictor of ICU mortality. Age, myoglobin and NT-proBNP levels predicted hospital mortality. Predictors of 6- month mortality were age, peak TnT, peak myoglobin and peak NT- proBNP levels. The APACHE II score did not predict mortality. A score was established dependent on TnT (<0.1 = 1, ≥0.1 = 2), age (<65 years = 1, ≥65 years = 2), BNP (<10,000 = 1, >10,000 = 2), and myoglobin (<750 = 1, >750 = 2). Patients were placed into tertiles (score = 4&5, 6, 7&8) to produce survival curves (Figure 1, P < 0.01). Results The CIG on day 1 predicted mortality (P = 0.001, analysis of variance). A novel score based on age and cardiac biomarkers predicts outcomes in severe sepsis and septic shock A CIG > 10 mmol/l correlated very strongly with mortality. The mortality in patients with a CIG < 10 mmol/l (n = 86) was 4.7%. The mortality in patients with a CIG > 10 mmol/l (n = 23) was 26.1% (P = 0.006, chi-square test). There were no differences in CIG with respect to mortality on admission or day 2 (P = 0.273 and 0.104, respectively). The mean hospital stay was significantly longer in patients with a CIG > 10 mmol/l (46.6 vs 18.7 days, P = 0.015, t test) (Table 1). TNFα promoter single nucleotide polymorphisms may influence gene expression in patients with severe sepsis Table 1 (abstract P449) Gene symbol Fold change Gene symbol Fold change TNFRSF1A 1.30 up IL1R1 1.50 up TNFRSF10D 1.21 up IL1R2 2.52 up TNFRSF25 1.19 down IL1RN 1.48 up Conclusion Compared with critically ill uninfected SIRS patients, sepsis increases IL-1α but not TNFα gene expression and does not increase TNF and IL-1 protein levels. Interestingly differential gene expression for TNF and IL-1 receptors exists, suggesting receptors, more than ligands, are important in differentiating sepsis from uninfected SIRS. Table 1 (abstract P449) Gene symbol Fold change Gene symbol Fold change TNFRSF1A 1.30 up IL1R1 1.50 up TNFRSF10D 1.21 up IL1R2 2.52 up TNFRSF25 1.19 down IL1RN 1.48 up Conclusion Compared with critically ill uninfected SIRS patients, sepsis increases IL-1α but not TNFα gene expression and does not increase TNF and IL-1 protein levels. Interestingly differential gene expression for TNF and IL-1 receptors exists, suggesting receptors, more than ligands, are important in differentiating sepsis from uninfected SIRS. Conclusion Compared with critically ill uninfected SIRS patients, sepsis increases IL-1α but not TNFα gene expression and does not increase TNF and IL-1 protein levels. Interestingly differential gene expression for TNF and IL-1 receptors exists, suggesting receptors, more than ligands, are important in differentiating sepsis from uninfected SIRS. Conclusion These results contradict previous in vitro functional studies on the TNF2 allele. This may be secondary to the method S178 Available online http://ccforum.com/supplements/11/S2 Table 1 (abstract P451) Conclusion In critically ill patients with severe sepsis/septic shock a score based on age and increased plasma levels of cardiac biomarkers can help risk-stratify patients and predict short-term (<6 months) outcome. Conclusion We describe the CIG for the first time in the critically ill surgical patient, and quantify it using simple bedside calculations derived from routine blood investigations. Failure to normalise the CIG by day 1 after admission to the HDU is an excellent marker for mortality and length of hospital stay, and should be used to guide resuscitation. Figure 1 (abstract P450) Table 1 (abstract P451) Day 1 Day 1 CIG < 10 mmol/l CIG > 10 mmol/l P value Inhospital mortality 4.7% (n = 86) 26.1% (n = 23) P = 0.006 (χ2 test) Length of hospital stay 18.7 days 46.6 days P = 0.015 (t test) P454 septic shock. Secondarily, we aimed at evaluating the impact of them in patient management Brain natriuretic peptide and left ventricular area variation with fluid challenge in septic shock: an echocardiographic study (preliminary results) Methods This transversal study included patients with severe sepsis or septic shock with a central venous line in place. Blood from a peripheral venous puncture, central venous line and arterial line were collected, at the same timepoint each 12 hours. Peripheral lactate collection was performed carefully with the left superior limb garroted for a maximal of 2 minutes. Data were analysed by linear correlation test, and a Bland–Altman test was done to verify the degree of agreement between values from different samples. A P value <0.05 was considered significant. A Ghaddab, H Quintard, L Rami, D Grimaud, C Ichai St Roch Hospital, Nice, France Critical Care 2007, 11(Suppl 2):P454 (doi: 10.1186/cc5614) Introduction Myocyte stretch is the main stimulus of brain natriuretic peptide (BNP) synthesis and release. During septic shock, important variations of volemia can occur and a correlation has been described between the cardiac index and the BNP level [1]. However, the relation between the echocardiographic left ventricule area and the BNP level has never been described. The aim of our study was to evaluate BNP and left ventricule area variations after an acute fluid loading in septic shock. Results Fifteen patients were enrolled, with a mean age of 57.8 years (eight males and seven females), APACHE II score of 15.3 ± 5.0 and SOFA score of 7.13 ± 3.39. A total of 129 samples were available for analysis. The linear correlation between arterial and central venous lactate levels showed an r2 = 0.66 (95% CI: 0.71–1.12). However, Bland–Altman had a mean ± standard deviation bias of 1.25 ± 5.0. Results were similar for arterial and peripheral venous lactate with an r2 = 0.85 (95% CI: 0.97–1.27) and a bias of –2.44 ± 5.0. Clinical agreement between arterial and central venous blood was 90%, arterial and peripheral blood was 71% and central venous and peripheral blood was 64%. Conclusion Lactate from central venous blood can replaced arterial samples. However, peripheral samples are not clinically reliable. Methods Mechanical ventilated patients with septic shock, and without anterior cardiac disease, were included in our study. A fluid challenge was performed with colloid (500 ml) in 30 minutes. A BNP blood sample was drawn before and 1 hour after fluid loading. P454 The primary endpoint was BNP variation after fluid challenge. Median values (25–75th percentiles) were compared with the Wilcoxon test (P < 0.05). The end-diastolic left ventricule area was recorded before and 1 hour after fluid challenge. Linear regression of BNP variation and left ventricular area variation was determined and r2 was calculated. Lactate levels from arterial, central venous and peripheral venous blood in severe sepsis and septic shock patients P453 Lung nitroxidative stress as a prognostic factor in ventilated septic patients J Gorrasi1, H Botti2, C Batthyany2, M Naviliat2, M Cancela1, R Ra 1University Hospital, School of Medicine, Montevideo, Uruguay; 2Center for Free Radical Biomedical Research, School of Medic Montevideo, Uruguay Critical Care 2007, 11(Suppl 2):P453 (doi: 10.1186/cc5613) Introduction During sepsis and mechanical ventilation, nitric o (•NO) is produced by lung cells. We study whether pulmonary production is a prognostic factor in mechanically ventilated se patients. Materials and methods We studied 50 patients with se within the first 48 hours of sepsis. Operating room patients se as control a group (ORCG) Nitrite and nitrate (NO –) and Lactate levels from arterial, central venous and peripheral venous blood in severe sepsis and septic shock patients M Assuncao, A Nascente, C Guedes, B Mazza, M Jacki, H Fernandes, F Machado Universidade Federal de São Paulo, Brazil Critical Care 2007, 11(Suppl 2):P452 (doi: 10.1186/cc5612) , Critical Care 2007, 11(Suppl 2):P452 (doi: 10.118 Conclusion In critically ill patients with severe sepsis/septic shock a score based on age and increased plasma levels of cardiac biomarkers can help risk-stratify patients and predict short-term (<6 months) outcome. Introduction Serial lactate measurements are reliable and may be useful as a prognostic marker in critically ill patients. Differences in its levels, depending on the sample site, can lead to mis- interpretation and inadequate treatment. The primary objective of this study is to evaluate the relationship between lactate levels in different compartments of the body, such as peripheral venous, central venous and arterial blood in patients with severe sepsis and S179 septic shock. Secondarily, we aimed at evaluating the impac them in patient management Methods This transversal study included patients with se sepsis or septic shock with a central venous line in place. B from a peripheral venous puncture, central venous line and art line were collected, at the same timepoint each 12 ho Peripheral lactate collection was performed carefully with the superior limb garroted for a maximal of 2 minutes. Data w analysed by linear correlation test, and a Bland–Altman test done to verify the degree of agreement between values different samples. A P value <0.05 was considered significant. Results Fifteen patients were enrolled, with a mean age 57.8 years (eight males and seven females), APACHE II scor 15.3 ± 5.0 and SOFA score of 7.13 ± 3.39. A total of samples were available for analysis. The linear correlation betw arterial and central venous lactate levels showed an r2 = 0 (95% CI: 0.71–1.12). However, Bland–Altman had a mea standard deviation bias of 1.25 ± 5.0. Results were simila arterial and peripheral venous lactate with an r2 = 0.85 (95% 0.97–1.27) and a bias of –2.44 ± 5.0. Clinical agreement betw arterial and central venous blood was 90%, arterial and periph blood was 71% and central venous and peripheral blood was 6 Conclusion Lactate from central venous blood can replaced art samples. However, peripheral samples are not clinically reliable. P457 Results Intravenous infusion of ANP reduced I/R-induced increase in serum levels of blood urea nitrogen and creatinine at 24 hours after reperfusion. ANP inhibited I/R-induced increases in renal tissue levels of TNF and myeloperoxidase at 3 and 6 hours after reperfusion, respectively. ANP significantly enhanced I/R-induced increases in renal tissue levels of CGRP and 6-keto-PGF1α, a stable metabolite of PGI2, at 1 hour after reperfusion. ANP-induced increases in renal tissue levels of CGRP were significantly inhibited by pretreatment with SB366791, a specific vanilloid receptor-1 antagonist. ANP-induced increases in renal tissue levels of 6-keto- PGF1α were significantly inhibited by pretreatment with SB366791, CGRP(8-37), a CGRP receptor antagonist, and indomethacin. Reduction of I/R-induced increases in serum levels of blood urea nitrogen and creatinine and those in renal tissue levels of TNF and myeloperoxidase in rats treated with ANP were completely abrogated by pretreatment with SB366791, CGRP(8- 37), and indomethacin. ANP significantly increased CGRP release from dorsal root ganglion neurons in vitro. Conclusions These results strongly suggested that ANP might Mid-regional pro-atrial natriuretic peptide is a strong predictor of outcome in an unselected cohort of critically ill patients Mid-regional pro-atrial natriuretic peptide is a strong predictor of outcome in an unselected cohort of critically ill patients Mid-regional pro-atrial natriuretic peptide is a strong predictor of outcome in an unselected cohort of critically ill patients B Meyer1, P Wexberg1, R Berger1, D Moertl1, N Morgenthaler2, J Struck2, A Bergmann2, G Heinz1, R Pacher1, M Huelsmann1 1Medical University of Vienna, Austria; 2B.R.A.H.M.S. Ag, Henningdorf, Germany Critical Care 2007, 11(Suppl 2):P456 (doi: 10.1186/cc5616) Conclusion There is no increase in BNP level in patients with septic shock after fluid challenge. To our knowledge, this preliminary study is the first to evaluate the relationship between BNP and left ventricule area variation in patient with septic shock. Although no statistical significance between left ventricule area variation and BNP variation after fluid challenge, there is a trend to correlation between these two parameters. More patients have to be included to confirm this result. Introduction Atrial natriuretic peptide (ANP) is a strong predictor of outcome in patients with heart failure, various other cardiovascular diseases and in patients with systemic inflammatory response syndrome and sepsis. Furthermore, ANP is elevated in patients with kidney disease. We aimed to test the prognostic potency of the precursor molecule mid-regional pro-atrial natriu- retic peptide (MR-pro-ANP) in an unselected cohort of critically ill patients. 1. McLean AS: The effects of acute fluid loading on plasma B-type natriuretic peptide levels in a septic shock patient. Anesth Intensive Care 2005, 33:528-530. 1. McLean AS: The effects of acute fluid loading on plasma B-type natriuretic peptide levels in a septic shock patient. Anesth Intensive Care 2005, 33:528-530. Methods Between August 2004 and February 2006, a total of 294 patients (191 males, age 63.8 ± 14.7 years) admitted to our ICU were studied. The mean SAPS2 and APACHE II score were 52 ± 23 and 24 ± 11, respectively. Two hundred and three patients (69.1%) were on intravenous inotropic support, 30 patients had additional mechanical circulatory support (23 intraaortic balloon counterpulsation (7.8%), eight extracorporeal membrane oxygenation (2.7%), three left ventricular assist device (0.9%)). Two hundred and five patients (69.7%) were mechanically ventilated, and 59 patients (20.1%) presented with acute renal failure. Plasma samples for determination of MR-pro-ANP were obtained on admission in all patients. As MR-pro-ANP values were not normally distributed, log MR-pro-ANP values were used for analysis. P455 Atrial natriuretic peptide reduces the ischemia/ reperfusion-induced renal injury in rats by enhancing sensory neuron activation N Harada, K Okajima, Y Mizuochi Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan Critical Care 2007, 11(Suppl 2):P455 (doi: 10.1186/cc5615) Introduction Although carpertide, a synthetic α-human atrial natriuretic peptide (ANP), reduces ischemia/reperfusion (I/R)- induced tissue injury, the precise therapeutic mechanism(s) remains to be elucidated. Calcitonin gene-related peptide (CGRP) released from sensory neurons reduces I/R-induced liver injury by inhibiting neutrophil activation through an increase in the endothelial production of prostacyclin (PGI2). In the present study, we examined in rats whether ANP reduces I/R-induced renal injury by enhancing sensory neuron activation. Results Two hundred and thirty-five patients (79.9%) survived to ICU discharge and 59 patients died (21.1%). Log MR-pro-ANP plasma levels were significantly higher in patients who died than in ICU survivors (2.76 ± 0.39 pmol/l vs 2.50 ± 0.38 pmol/l, respectively, P < 0.0001). In the Kaplan–Meier analysis of 28-day survival, patients with log MR-pro-ANP plasma-levels above the median had significantly lower survival rates compared with patients with log MR-pro-ANP plasma levels below the median (P = 0.02). Methods The right renal vessels were clamped in rats for 45 minutes after left nephrectomy. ANP (0.3 µg/kg/min) was continuously infused from 30 minutes before ischemia to 60 minutes after reperfusion. We attempted to determine whether ANP promotes CGRP release from cultured dorsal root ganglion neurons isolated from adult rats in vitro. Conclusion Our data show that elevated plasma levels of MR-pro- ANP at ICU admission are associated with an adverse outcome in an unselected cohort of critically ill patients. Lung nitroxidative stress as a prognostic factor in ventilated septic patients Lung nitroxidative stress as a prognostic factor in ventilated septic patients J Gorrasi1, H Botti2, C Batthyany2, M Naviliat2, M Cancela1, R Radi2 1University Hospital, School of Medicine, Montevideo, Uruguay; 2Center for Free Radical Biomedical Research, School of Medicine, Montevideo, Uruguay Critical Care 2007, 11(Suppl 2):P453 (doi: 10.1186/cc5613) Figure 1 (abstract P454) Figure 1 (abstract P454) Figure 2 (abstract P454) Introduction During sepsis and mechanical ventilation, nitric oxide (•NO) is produced by lung cells. We study whether pulmonary •NO production is a prognostic factor in mechanically ventilated septic patients. Materials and methods We studied 50 patients with sepsis within the first 48 hours of sepsis. Operating room patients served as control a group (ORCG). Nitrite and nitrate (NOx–) and 3- nitrotyrosine (3NT) in plasma and bronchoalveolar lavage fluid (BALF) were analyzed by the Griess/vanadium chloride method and ELISA, respectively. Results were expressed as median and interquartile range. Receiver operator curves were constructed to compare the predictive value of NOx– values in BALF at admission with other variables. Kaplan–Meier analysis was used to compare survival between high and low BALF NOx– levels at admission. A P value less than 0.05 was considered significant. Figure 2 (abstract P454) Results At study admission in the sepsis group, nonsurvivors had higher levels of BALF NOx– than survivors: 20 (17–33) µM, 27 versus 72 (46–91) µM, 23, P = 0.0001. At day 7, BALF 3NT was higher in nonsurvivor septic patients than in survivors: 1,666 (30–3,173) pmol/mg protein versus 291 (13–1,908) pmol/mg protein. BALF NOx – had the highest area under the receiver operator curve for mortality (0.812, P = 0.001) in relation to other variables. Septic patients with BALF NOx – above 36 µM had a relative risk for mortality of 4.23 and an OR of 15.84. The difference between the low bronchoalveolar •NO group (BALF [NOx –] < 36 µM at admission) versus the high bronchoalveolar •NO group (BALF [NOx –] ≥36 µM at admission) in ICU mortality was significant: 19% versus 78% (log rank 18.19, P = 0.00001). Conclusion During sepsis there is enhanced lung •NO production that is associated with ICU mortality. S180 Available online http://ccforum.com/supplements/11/S2 P456 Results Eight patients (median age 68 years; six males/two females; SOFA score = 12) were enrolled in our study. The initial BNP level median increased from 695 (417–2,738) to 715 (478–2,596) µg/ml after a fluid loading (P = 0.7) (Figure 1).We did not find a statistically significant relationship between BNP variation and left ventricule area variation after fluid challenge (P = 0.13) (Figure 2). Clinical meaning of brain natriuretic peptide in the intensive care unit The BNP cutoff value to discriminate group B is 274 pg/ml with sensibility 90 (IC95 = specificity 79 (IC95 = 61–91). Conclusions Risk of weaning failure is increased f patients with HD. BNP values of group B patients are normal people probably because the heart of ICU submitted to different kinds of stress; therefore the value to consider for discrimination of patients w patients without HD in the ICU should be higher. BN in ICU patients with good performance of the hear protective response to stress performed by thera during the ICU stay, this response is absent in patie because their hearts already work in safety mode. P458 Combining various severity of illness scoring sy improve outcome prediction: pilot experience in critically ill obstetric population Z Haddad1, C Kaddour2, L Skandrani2, S Nagi2, T C R Souissi2 1CHI St-Cloud, France; 2National Institute of Neurolog Tunisia Critical Care 2007, 11(Suppl 2):P458 (doi: 10.1186/c Introduction No perfect severity score exists to mortality, thus the search for new systems is still a pre Hypothesis Use of many severity of illness scores si improves mortality prediction. Patients and methods An open prospective observ as part of the APRiMo project [1]. The study period 1996–September 2004. Inclusion criteria were obstetric patients and ICU length of stay >24 hou criteria were those of the used scores. The main interest was the survival status at ICU discharge. T was divided into two samples: development an datasets. Development database patients were chos (n = 414) and the remaining patients composed t dataset (n = 229). A multivariable logistic regressio developed to predict mortality associating the Acut and Chronic Health Evaluation II score [2], Simp Physiology Score II [3], Admission Mortality Pred (MPM-H0) and Day 1 Mortality Prediction Model (MP Di i i ti d lib ti d b Table 1 (abstract P458) Development Validation Hosmer–Lemeshow 0.868 0.42 C-hat statistics test ROC 0.936 0.945 Nonsurvivor prediction 28/46 (60.9%) 18/28 (64.3%) Survivor prediction 364/368 (99%) 199/201 (99%) nominal variables were analyzed with the chi-square test and the risk ratio (RR) with 95% confidence interval (IC95) was performed; intragroup ordinal variables were analyzed with the Wilcoxon test (W), intergroup ordinal variables were analyzed with the Mann–Whitney test (MW). The receiver operative characteristic test was used to discriminate the BNP cutoff value with sensibility, specificity and respective IC95, between group A and group B. P < 0.01 is taken as statistically significant. References 1. Haddad Z, et al.: Critically ill obstetric patients: outcome and predictability. Crit Care 2005, 9(Suppl 1):S92-S93. Conclusions Risk of weaning failure is increased four times in patients with HD. BNP values of group B patients are higher than normal people probably because the heart of ICU patients is submitted to different kinds of stress; therefore the BNP cutoff value to consider for discrimination of patients with HD from patients without HD in the ICU should be higher. BNP production in ICU patients with good performance of the heart is the right protective response to stress performed by therapy adopted during the ICU stay, this response is absent in patients with HD because their hearts already work in safety mode. 2. Knaus WA, et al.: APACHE II: a severity of disease classifi- cation system. Crit Care Med 1985, 13:818-829. 3. Le Gall JR, et al.: A new simplified acute physiology score (SAPS II) based on a European/North American multicen- ter study. JAMA 1993, 270:2957-2963. 4. Lemeshow S, et al.: Refining intensive care unit outcome prediction by using changing probabilities of mortality. Crit Care Med 1988, 16:470-477. P459 Combining various severity of illness scoring systems to improve outcome prediction: pilot experience in the critically ill obstetric population Z Haddad1, C Kaddour2, L Skandrani2, S Nagi2, T Chaaoua2, R Souissi2 1CHI St-Cloud, France; 2National Institute of Neurology, Tunis, Tunisia Critical Care 2007, 11(Suppl 2):P458 (doi: 10.1186/cc5618) Z Haddad1, C Kaddour2, L Skandrani2, S Nagi2, T Chaaoua2, R Souissi2 1CHI St-Cloud, France; 2National Institute of Neurology, Tunis, Tunisia Critical Care 2007, 11(Suppl 2):P458 (doi: 10.1186/cc5618) Clinical meaning of brain natriuretic peptide in the intensive care unit Results Weaning failure in group A occurred in 50% of patients vs 12% of group B patients (P < 0.01 chi-square test; RR = 4.13, IC95 = 1.36–12.49). BNP value differences in group A are not significant (step 1: 662 ± 147 pg/ml; step 2: 769 ± 171 pg/ml; step 3: 843 ± 167 pg/ml), while BNP value differences in group B are statistically significant (W) (step 1: 130 ± 21 pg/ml; step 2: 236 ± 41 pg/ml, P < 0.01 vs step 1; step 3: 375 ± 75 pg/ml, P < 0.001 vs step 1 and P < 0.01 vs step 2). There are statistically significant differences between group A and group B in every step (P < 0.01 MW). The BNP cutoff value to discriminate group A from group B is 274 pg/ml with sensibility 90 (IC95 = 55–98) and specificity 79 (IC95 = 61–91). Results Six hundred and forty-three patients enrolled. The overall mortality rate was 11.51%. The new model predicted accurately 99% of survivors and more than 60% of nonsurvivors. Conclusion The ‘multiscore’ model seems to refine prognosis. This is partly due to mixing of new evaluated parameters. Testing the latest developed generations of scores and also organ dysfunction systems could be interesting. Clinical meaning of brain natriuretic peptide in the intensive care unit T Principi, D Elisei, M Strovegli, G Falzetti, P Pelaia Anaesthesia and Intensive Care Clinic – Politechnical University of Marche, Ancona, Italy Critical Care 2007, 11(Suppl 2):P457 (doi: 10.1186/cc5617) Introduction The aim of this study is to evaluate differences in brain natriuretic peptide (BNP) dosage (vn < 100 pg/ml) during the weaning procedure, in patients with heart disease (HD) vs patients without HD, admitted to the ICU. Introduction The aim of this study is to evaluate differences in brain natriuretic peptide (BNP) dosage (vn < 100 pg/ml) during the weaning procedure, in patients with heart disease (HD) vs patients without HD, admitted to the ICU. Methods Ten patients with HD (group A) and 33 patients without HD (group B) were studied by BNP dosage in three specific steps: (1) admission to the ICU; (2) before the extubation (performed if patients, after the end of mechanical ventilation and 1 hour of connection to T-tube, were considered suitable for extubation); and (3) 24 hours after extubation. Necessity of noninvasive ventilation or reintubation after the extubation was considered as weaning failure. Data are shown as the mean ± standard error of the mean; Conclusions These results strongly suggested that ANP might reduce I/R-induced renal injury in rats by inhibiting neutrophil activation through enhancement of sensory neuron activation. S181 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin nominal variables were analyzed with the chi-square risk ratio (RR) with 95% confidence interval (IC95) wa intragroup ordinal variables were analyzed with the W (W), intergroup ordinal variables were analyze Mann–Whitney test (MW). The receiver operative c test was used to discriminate the BNP cutoff value wi specificity and respective IC95, between group A a P < 0.01 is taken as statistically significant. Results Weaning failure in group A occurred in 50% o 12% of group B patients (P < 0.01 chi-square test IC95 = 1.36–12.49). BNP value differences in grou significant (step 1: 662 ± 147 pg/ml; step 2: 769 ± step 3: 843 ± 167 pg/ml), while BNP value difference are statistically significant (W) (step 1: 130 ± 21 pg 236 ± 41 pg/ml, P < 0.01 vs step 1; step 3: 375 P < 0.001 vs step 1 and P < 0.01 vs step 2). There ar significant differences between group A and group B (P < 0.01 MW). Combining various severity of illness scoring systems to improve outcome prediction: pilot experience in the critically ill obstetric population Validation of logistic organ dysfunction score prediction compared with APACHE II score prediction hospital outcome in Thai patients B Khwannimit B Khwannimit Prince of Songkla University, Songkhla, Thailand Critical Care 2007, 11(Suppl 2):P459 (doi: 10.1186/cc5619) Introduction To assess the performance of the logistic organ dysfunction (LOD) score and Acute Physiology and Chronic Health Evaluation II (APACHE II) score in a mixed medical–surgical ICU of a tertiary referral university hospital in Thailand. Introduction No perfect severity score exists to predict ICU mortality, thus the search for new systems is still a preoccupation. Hypothesis Use of many severity of illness scores simultaneously improves mortality prediction. Introduction No perfect severity score exists to predict ICU mortality, thus the search for new systems is still a preoccupation. Hypothesis Use of many severity of illness scores simultaneously improves mortality prediction. Figure 1 (abstract P459) Figure 1 (abstract P459) P460 Could we use the admission Acute Physiology and Chronic Health Evaluation II score for outcome prediction in critically ill obstetric patients? Objective Development of a new prognostic model based on association of one of the generalistic severity scores (SAPS II, APACHE II), one of the organ dysfunction scores (LOD, MODS, SOFA) and evolution of these scores during the first 2 days of ICU hospitalization. Z Haddad1, R Souissi2, C Kaddour2, W Trabelsi2, M Bouchnak3, S Nagi2 1CHI St-Cloud, France; 2National Institute of Neurology, Tunis, Tunisia; 3Centre de Maternité et de Néonatologie, Tunis, Tunisia Critical Care 2007, 11(Suppl 2):P460 (doi: 10.1186/cc5620) Z Haddad1, R Souissi2, C Kaddour2, W Trabelsi2, M Bouchnak3, S Nagi2 1CHI St-Cloud, France; 2National Institute of Neurology, Tunis, Tunisia; 3Centre de Maternité et de Néonatologie, Tunis, Tunisia Critical Care 2007, 11(Suppl 2):P460 (doi: 10.1186/cc5620) Methods An open prospective analysis part of the APRiMo study [1] ranging from January 1996 to September 2004. Inclusion criteria were critically ill obstetric patients with an ICU length of stay > 24 hours. Exclusion criteria were those of the used scores. The main outcome of interest was survival status at ICU discharge. The database was divided into two samples: a development sample by random choice of 450 patients, and the remaining patients in the validation dataset. Multivariable logistic regression models were developed. We chose among different developed models the best performer as assessed by Hosmer–Lemeshow (HL) goodness-of-fit statistics (calibration) and the area under the receiver operating characteristic curve (AUROC) for discrimination. Accuracy of the developed model was verified on the validation dataset using the same statistical tests. Results are expressed as the mean ± standard deviation unless stated elsewhere. Data were computed on SPSS 11.5 Win-XP version. Introduction The APACHE II score (APII) has widespread use in ICUs for research and benchmarking. Physiological data for calculation of the APII score derive from worst values in the first 24 hours after ICU admission. Hypothesis Mortality prediction by the APII system depends on data sampling. Use of ICU admission data (first hour) could be accurate to predict mortality. Methods An open prospective data-sampling part of the APRiMo study. Included were critically ill obstetric patients, with ICU length of stay (LOS) ≥6 hours. Admission (H1: first-hour worst physiological data) and H24 (worst 24-hour physiological variables including H1 collected data) were used to generate, respectively: the admission APII score (H1-APII) and H24-APII. Reference 1. Knaus WA, et al.: APACHE II: a severity of disease classifi- cation system. Crit Care Med 1985, 13:818-829. 1. Knaus WA, et al.: APACHE II: a severity of disease classifi- cation system. Crit Care Med 1985, 13:818-829. P461 Two-day intensive care unit outcome prediction score: a trial to improve outcome prediction in critically ill obstetric patients Z Haddad1, S Nagi2, R Souissi2, C Kaddour2 Introduction The critically ill obstetric population median ICU stay is 4 days, thus general severity of illness scores are supposed to be accurate in mortality prediction. A literature review makes us sceptical. P460 The formulae to calculate individual mortality for H1 and H24 APII were those validated for H24-APII as stated by Knaus and colleagues [1], adjusting for admission diagnosis. We compared both scores by discrimination and calibration statistical tests. P < 0.05 was the threshold for statistical significance. Results Six hundred and forty patients included. Age 31 ± 6 years, length of stay 5 ± 5 days, SAPS II 27 ± 16, SOFA score 5 ± 4, LOD score 2 ± 1.7. The overall mortality rate was 13.3%. The best model was the one combining SAPS II and LOD scores. The LOD score and SAPS II alone discriminated well but calibrated poorly in outcome prediction. Discrimination was optimal for the new developed model in both development and validation datasets, with AUROC respectively of 0.87 and 0.85. Calibration was good in the developed and validated datasets, respectively P = 0.176 and 0.34. The developed model predicts death accurately in 2/3 cases. Results The study period was January 1996–September 2004. We included 541 patients, overall mortality was 10.5%. Mean H1- APII and H24-APII scores. respectively. were 7.6 ± 6.1 and 8.6 ± 7, with derived mean predicted mortality, respectively, of 8.63% and 9.86%. The H24-APII score was higher than the H1-APII score in 135 patients (25%), among those patients 32 died (24% of patients with worsened APII) vs 6.16% if H1 = H24 (P < 0.01). Running a multiple logistic regression with mortality as the dependent parameter, we found that worsening of the APII score over time is not significantly associated with mortality (P = 0.791), whereas the H1-APII score (P < 0.001) and ∆APII score (H24-APII Discussion and conclusion The SAPS II and LOD scores are complementary. Development of dynamic models in time helps to refine prognosis prediction. Discussion and conclusion The SAPS II and LOD scores are complementary. Development of dynamic models in time helps to refine prognosis prediction. Figure 1 (abstract P459) P460 Could we use the admission Acute Physiology and Chronic Health Evaluation II score for outcome prediction in critically ill obstetric patients? Z Haddad1, R Souissi2, C Kaddour2, W Trabelsi2, M Bouchnak3, S Nagi2 1CHI St-Cloud, France; 2National Institute of Neurology, Tunis, Tunisia; 3Centre de Maternité et de Néonatologie, Tunis, Tunisia Critical Care 2007, 11(Suppl 2):P460 (doi: 10.1186/cc5620) Methods The data were collected prospectively on consecutive patients admitted to the ICU of Songklanagarind Hospital over a 24-month period from 1 July 2004 until 30 June 2006. minus H1-APII score) (P = 0.04) are correlated with mortality. Respective ORs are 1.28 and 1.45. Overall discrimination ability assessed by receiver operating characteristic curves was good for H1-APII (0.78) and H24-APII (0.784) (P = 0.834). 24 month period from 1 July 2004 until 30 June 2006. Results A total of 1,962 patients were enrolled, with 432 deaths (22%) prior to hospital discharge. Both systems provided overprediction of hospital mortality. LOD and APACHE II scores predicted hospital mortality of 25.4 ± 26.5 and 29.6 ± 27.8, respectively. Both models showed excellent discrimination. The receiver operating characteristic curves of both systems are shown in Figure 1. The area under the receiver operating characteristic curve (AUROC) of LOD was 0.867 (95% CI = 0.846–0.886) and the AUROC was 0.906 (95% CI = 0.889–0.923) for APACHE II. Both models presented a poor calibration in overall population. However, the LOD score had good discrimination and calibration in subgroups of nonoperative patients (AUROC 0.854, the Hosmer–Lemeshow goodness-of-fit H statistic 11.67, P = 0.166) and patients that exclude coronary artery disease and cardiac surgery (AUROC 0.860, the Hosmer–Lemeshow goodness-of-fit H statistic 10.03, P = 0.263). Conclusion The LOD score showed good accuracy to predict hospital mortality in subgroups of nonoperative critically ill patients and excluded coronary heart disease and cardiac surgical critically ill patients in Thailand. Conclusion To avoid variation in APII mortality prediction caused by variable sample rates, the admission APII is reliable. Customizing mortality formulae could improve performances of APII-H1. Figure 1 (abstract P459) Patients and methods An open prospective observational study as part of the APRiMo project [1]. The study period was January 1996–September 2004. Inclusion criteria were critically ill obstetric patients and ICU length of stay >24 hours. Exclusion criteria were those of the used scores. The main outcome of interest was the survival status at ICU discharge. The database was divided into two samples: development and validation datasets. Development database patients were chosen randomly (n = 414) and the remaining patients composed the validation dataset (n = 229). A multivariable logistic regression model was developed to predict mortality associating the Acute Physiology and Chronic Health Evaluation II score [2], Simplified Acute Physiology Score II [3], Admission Mortality Prediction Model (MPM-H0) and Day 1 Mortality Prediction Model (MPM-H24) [4]. Discrimination and calibration were assessed by goodness-of-fit C-hat statistics and area under the ROC curve. The developed model was then tested in the validation dataset. Good discrimination was retained if C-hat statistics P > 0.1 and good calibration if area under the ROC curve > 0.8. S182 Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Methods The data were collected prospectively on consecutive patients admitted to the ICU of Songklanagarind Hospital over a 24-month period from 1 July 2004 until 30 June 2006. Results A total of 1,962 patients were enrolled, with 432 deaths (22%) prior to hospital discharge. Both systems provided overprediction of hospital mortality. LOD and APACHE II scores predicted hospital mortality of 25.4 ± 26.5 and 29.6 ± 27.8, respectively. Both models showed excellent discrimination. The receiver operating characteristic curves of both systems are shown in Figure 1. The area under the receiver operating characteristic curve (AUROC) of LOD was 0.867 (95% CI = 0.846–0.886) and the AUROC was 0.906 (95% CI = 0.889–0.923) for APACHE II. Both models presented a poor calibration in overall population. However, the LOD score had good discrimination and calibration in subgroups of nonoperative patients (AUROC 0.854, the Hosmer–Lemeshow goodness-of-fit H statistic 11.67, P = 0.166) and patients that exclude coronary artery disease and cardiac surgery (AUROC 0.860, the Hosmer–Lemeshow goodness-of-fit H statistic 10.03, P = 0.263). Conclusion The LOD score showed good accuracy to predict hospital mortality in subgroups of nonoperative critically ill patients and excluded coronary heart disease and cardiac surgical critically ill patients in Thailand. Figure 1 (abstract P462) Results Nine out of 11 patients survived without any residual organ damage, and the remaining two died due to MODS (Figure 1). Both these patients had five organ dysfunctions on admission, and their SOFA scores were 18 and 20, respectively. They had a low parasitic index of 1% and 2.5% and their PCT levels were 0.5–2 and >10 (semiquantitative method), respectively. Their APACHE II scores were 16 and 10. Conclusion The pretreatment APACHE II score, parasite index, PCT levels and number of organs involved have variable correlation with mortality and are not consistent predictors of outcome. A higher SOFA score on admission is a more reliable predictor of mortality in malarial MODS. Model calibration and discriminatory ability: a comparison of four derived variables from the SOFA score and the SAPS II Model calibration and discriminatory ability: a comparison of four derived variables from the SOFA score and the SAPS II Median length of ICU stay in patients with an admission SOFA score >8 vs those whose admission SOFA score was ≤8 (P = 0.001). Median length of ICU stay in patients with an admission SOFA score >8 vs those whose admission SOFA score was ≤8 (P = 0.001). R Ouezini, N Frikha, N Belhaj, S Ouerghi, M Mebazaa, M Ben Ammar Mongi slim Hospital, La Marsa, Tunisia Critical Care 2007, 11(Suppl 2):P464 (doi: 10.1186/cc5624) R Ouezini, N Frikha, N Belhaj, S Ouerghi, M Mebazaa, M Ben Ammar Mongi slim Hospital, La Marsa, Tunisia Critical Care 2007, 11(Suppl 2):P464 (doi: 10.1186/cc5624) R Ouezini, N Frikha, N Belhaj, S Ouerghi, M Mebazaa, M Ben Ammar Mongi slim Hospital, La Marsa, Tunisia Critical Care 2007, 11(Suppl 2):P464 (doi: 10.1186/cc5624) P462 The correlation of the Sequential Organ Failure Assessment score with intensive care unit outcome They had a low parasitic index of 1% and 2.5% and their PCT levels were 0.5–2 and >10 (semiquantitative method), respectively. Their APACHE II scores were 16 and 10. Conclusion The pretreatment APACHE II score, parasite index, PCT levels and number of organs involved have variable correlation with mortality and are not consistent predictors of outcome. A higher SOFA score on admission is a more reliable predictor of mortality in malarial MODS. P464 Model calibration and discriminatory ability: a comparison of four derived variables from the SOFA score and the SAPS II R Ouezini, N Frikha, N Belhaj, S Ouerghi, M Mebazaa, M Ben Ammar Mongi slim Hospital, La Marsa, Tunisia Critical Care 2007, 11(Suppl 2):P464 (doi: 10.1186/cc5624) Objective We prospectively evaluated the correlation of the APACHE II score, parasite index, procalcitonin (PCT) levels, number of organ dysfunctions/failures and Sequential Organ Failure Assessment (SOFA) score with the outcome of severe malaria. Methods Eleven patients with acute severe malaria with MODS were treated in our ICU in the last 5 months. All these patients were treated with artesunate and/or quinine as per the WHO antimalarial treatment schedule, along with standard ICU care. The APACHE II and SOFA scores were calculated on admission. PCT levels were measured semiquantitatively on admission. The parasite index was confirmed by two pathologists. Conclusion Maximum and admission SOFA scores are of prognostic value in the intensive care setting; allowing patients with increased risk of mortality and prolonged stay to be identified. Figure 1 (abstract P462) Median length of ICU stay in patients with an admission SOFA score >8 vs those whose admission SOFA score was ≤8 (P = 0.001). Figure 1 (abstract P462) P462 P462 P462 The correlation of the Sequential Organ Failure Assessment score with intensive care unit outcome I Ketchley, A Theodoraki, T Reynolds, A Tillyard, R Lawson, N Al-Subaie, M Cecconi, R Grounds, A Rhodes St George’s Hospital, London, UK Critical Care 2007, 11(Suppl 2):P462 (doi: 10.1186/cc5622) Methods We conducted a prospective observational review of 100 consecutive patients admitted to our ICU. We collected data relating to daily maximum organ dysfunction scores. Outcome was defined in terms of length of ICU stay and ICU mortality. Results We included 100 patients (62 males), mean age 60.9 years. Of these admissions, 45 were elective surgical, 22 emergency surgical, 33 medical. The median Sequential Organ Failure Assessment (SOFA) score on admission was 4.50 (IQR 4). The median maximum SOFA score was 5.00 (IQR 5). The median length of ICU stay was 3.0 days (IQR 3). The overall ICU mortality rate was 14.0%. For patients with a maximum SOFA score ≤8, mortality was 5.1% – vs 45.5% for those whose maximum SOFA score was >8 (P < 0.001). Sixty-four per cent of patients scored their maximum SOFA score on admission. In patients whose SOFA score increased after admission, the mortality was 24.3%. Logistic regression analysis showed the maximum SOFA score bore a stronger correlation with mortality than admission SOFA score. See Figure 1. like India, and is associated with significant mortality. The outcome of malarial MODS predicted in various studies is extremely variable and dependent on many patient parameters. like India, and is associated with significant mortality. The outcome of malarial MODS predicted in various studies is extremely variable and dependent on many patient parameters. Objective We prospectively evaluated the correlation of the APACHE II score, parasite index, procalcitonin (PCT) levels, number of organ dysfunctions/failures and Sequential Organ Failure Assessment (SOFA) score with the outcome of severe malaria. Methods Eleven patients with acute severe malaria with MODS were treated in our ICU in the last 5 months. All these patients were treated with artesunate and/or quinine as per the WHO antimalarial treatment schedule, along with standard ICU care. The APACHE II and SOFA scores were calculated on admission. PCT levels were measured semiquantitatively on admission. The parasite index was confirmed by two pathologists. Results Nine out of 11 patients survived without any residual organ damage, and the remaining two died due to MODS (Figure 1). Both these patients had five organ dysfunctions on admission, and their SOFA scores were 18 and 20, respectively. Reference 1. Haddad Z, et al.: Critically ill obstetric patients: outcome and predictability. Crit Care 2005, 9(Suppl 1):S92-S93. 1. Haddad Z, et al.: Critically ill obstetric patients: outcome and predictability. Crit Care 2005, 9(Suppl 1):S92-S93. S183 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Figure 1 (abstract P463) P462 The correlation of the Sequential Organ Failure Assessment score with intensive care unit outcome I Ketchley, A Theodoraki, T Reynolds, A Tillyard, R Lawson, N Al-Subaie, M Cecconi, R Grounds, A Rhodes St George’s Hospital, London, UK Critical Care 2007, 11(Suppl 2):P462 (doi: 10.1186/cc5622) Figure 1 (abstract P463) Figure 1 (abstract P463) Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Figure 1 (abstract P464) Results One hundred and seventy-six patients were studied (71 males (56%), median age 51 (IQR 36–67) years, 78 (44%) with severe sepsis, median length of ICU stay 10 days (IQR 7–16), median admission SOFA 6 (IQR 4–9), median APACHE II score 19 (IQR 13–26), ICU mortality 27.84% (49/176 patients)). The SOFA score and its components scores along the five admission days distinguished the survivors from the nonsurvivors. Considering the SOFA score and its respiratory, neurologic and circulatory components, survivors presented lower scores as the days passed (P < 0.001). Mortality was increasingly higher for those patients who persisted with a SOFA score ≥7 as the days passed. *Classified as + if predicted mortality ≥0.5. Domax, the maximum number of organ failures during ICU stay. *Classified as + if predicted mortality ≥0.5. Domax, the maximum number of organ failures during ICU stay. Conclusion In the sample studied, the persistence of an elevated SOFA score and its components during the first 5 days of admission predicted a higher mortality. Survival appears to be related to early organ dysfunction recovery. The SOFA score and SOFA-related variables’ day-to-day changes in a population of septic patients may have an important prognostic implication and some patterns of daily evolution may distinguish those patients with a more ominous outcome. ∆SOFA was defined by TMS minus admission SOFA (SOFAi). The maximum SOFA was defined by the worst SOFA value during the ICU stay. Logistic regression modeling techniques were used to describe the association of derived SOFA variables and SAPS II with mortality. ROC curves were used to assess the model’s discriminatory ability and we examined the model calibration using the Hosmer–Lemeshow goodness-of-fit test. P < 0.05 was con- sidered significant. ∆SOFA was defined by TMS minus admission SOFA (SOFAi). The maximum SOFA was defined by the worst SOFA value during the ICU stay. Logistic regression modeling techniques were used to describe the association of derived SOFA variables and SAPS II with mortality. ROC curves were used to assess the model’s discriminatory ability and we examined the model calibration using the Hosmer–Lemeshow goodness-of-fit test. P < 0.05 was con- sidered significant. P466 Results Diagnostic categories were: trauma 21.3%, postoperative 19% and medical 59.7%. Global mortality was 34.3%. Survivors had lower average SAPS II (28.1 ± 14 against 48.6 ± 19, P < 0.01), SOFAi score (3.7 ± 3 against 7.2 ± 4, P < 0.01), SOFAmax score (4.6 ± 4 against 10.8 ± 3, P < 0.01), ∆SOFA (1.6 ± 6 against 4.2 ± 3, P < 0.01), DoMAX (1.6 ± 6 against 4.2 ± 3, P < 0.01) and TMS (5 ± 3 against 11.4 ± 4, P < 0.01), and the difference was statistically significant. Results regarding model calibration and discriminatory ability are presented in Figure 1. Cumulative lactate load correlates with cumulative Sequential Organ Failure Assessment score and survival in intensive care unit patients Cumulative lactate load correlates with cumulative Sequential Organ Failure Assessment score and survival in intensive care unit patients Cumulative lactate load correlates with cumulative Sequential Organ Failure Assessment score and survival in intensive care unit patients P Spronk1, L Brander2, S Jansen1, J Rommes1 1Gelre Ziekenhuizen Location Lukas, Apeldoorn, The Netherlands; 2University Hospital, Bern, Switzerland Critical Care 2007, 11(Suppl 2):P466 (doi: 10.1186/cc5626) Background Changes in lactate levels are used as a prognostic marker in critically ill patients. However, the relation between the time course of arterial blood lactate clearance and important outcome parameters such as ICU length of stay (LOS), incidence of organ failure and survival rate has not been established. Conclusion The SOFAmax score had the best model calibration and could be used to compare different patient populations in terms of mortality. Methods Case records from all ICU patients admitted between 2002 and 2004 were retrospectively identified in the ICU database. The Sequential Organ Failure Assessment (SOFA) score was calculated daily to assess the time course of organ failure. All lactate levels were extracted and the total cumulative lactate load (area under the curve above the upper normal level of 2.2 mmol/l; cum-lactate), and total cumulative SOFA score (cum- SOFA) were calculated and related to ICU LOS and final hospital survival. Values are the median (interquartile range). P465 P465 Sequential Organ Failure Assessment score trends and sepsis survival in a Brazilian university hospital intensive care unit D Moreira Lima, B Ferreira Cordeiro de Almeida, R Cordioli, E Tadeu Azevedo Moura, I Schimdtbauer, A Nassar, F Maria Queiroz Silva, R Zigaib, D Forte, F Giannini, J Coelho, M Park Hospital das Clínicas FMUSP, São Paulo, Brazil Critical Care 2007, 11(Suppl 2):P465 (doi: 10.1186/cc5625) Sequential Organ Failure Assessment score trends and sepsis survival in a Brazilian university hospital intensive care unit D Moreira Lima, B Ferreira Cordeiro de Almeida, R Cordioli, E Tadeu Azevedo Moura, I Schimdtbauer, A Nassar, F Maria Queiroz Silva, R Zigaib, D Forte, F Giannini, J Coelho, M Park Hospital das Clínicas FMUSP, São Paulo, Brazil Critical Care 2007, 11(Suppl 2):P465 (doi: 10.1186/cc5625) Results Observations in 1,711 ICU admissions were analyzed, age was 69 (57–77) years, cum-lactate was 420 (94–419 min·mmol/l) and cum-SOFA was 11 (4–38). Cum-SOFA was higher in patients with hyperlactatemia (cum-lactate > 0) during the ICU stay (n = 782; 24 (7–71)) than in those without (5 (3–20); P < 0.001). Cum-SOFA correlated with cum-lactate and with ICU LOS, and cum-lactate correlated with ICU LOS (all P < 0.001). In patients who died in the hospital (n = 329), cum-lactate (1,180 (203–3,427) min·mmol/l) and cum-SOFA (30 (10–95)) were higher than in hospital survivors (n = 1,382; 298 (73–1,154) min·mmol/l, and 22 (5–67); both P < 0.001). In emergency admissions, cum-lactate (484 (113–2,031)) and cum-SOFA (27 (8–78)) were higher than in planned admissions (131 (37–454)) and (4 (3–28); both P < 0.001), respectively. Introduction Sepsis is associated with progressive organ failure. We sought to describe Sequential Organ Failure Assessment (SOFA) score daily trends in septic patients and tried to correlate those trends with survival. Methods Patients with severe sepsis or septic shock admitted for at least 5 days in a seven-bed medicosurgical ICU of a Brazilian university hospital were studied. The daily SOFA score for each patient was calculated during the first 5 days of admission. Relevant data were prospectively acquired from March 2003 to May 2006 and the latter retrieved from a electronic database. ICU survivors were compared with nonsurvivors using the Mann–Whitney U test. Day-to-day changes were verified within each group using Friedman’s test. P ≤0.01 was elected as the significance limit. Medians and interquartile ranges (IQRs) were used to describe the sample. P463 P463 Sequential Organ Failure Assessment score as an outcome predictor in malarial multiorgan dysfunction syndrome S Jog, P Akole, B Pawar, N Gogate, S Gadgil, P Rajhans Deenanath Mangeshkar Hospital and Research Centre, Pune, India Critical Care 2007, 11(Suppl 2):P463 (doi: 10.1186/cc5623) Introduction Acute severe malaria is one of the leading causes of Sequential Organ Failure Assessment score as an outcome predictor in malarial multiorgan dysfunction syndrome Introduction We sought to compare four derived variables from the SOFA score and the SAPS II in ICU patients in terms of discriminatory ability and model calibration. Introduction We sought to compare four derived variables from the SOFA score and the SAPS II in ICU patients in terms of discriminatory ability and model calibration. Patients and methods Four hundred and fourteen patients were included; they were evaluated on admission and every 48 hours thereafter until ICU discharge or death. Readmission and patients with an ICU stay shorter than 48 hours were excluded. The TMS score was calculated by summing the worst scores for each of the organ systems. Organ failure was defined by a SOFA score ≥3. Introduction Acute severe malaria is one of the leading causes of multiorgan dysfunction syndrome (MODS) in a developing country S184 Available online http://ccforum.com/supplements/11/S2 P469 Results PCT serum concentrations are presented in Table 1. In groups A, B, and C, SOFA1 was 1.31 ± 1.67 vs 1.62 ± 1.65 (P > 0.05), and 4.73 ± 2.57 (P < 0.05). SOFA2 was 0.97 ± 1.56 vs 1.34 ± 1.67 (P > 0.05), vs 4.69 ± 2.47 (P < 0.05). SOFA3 was 0.63 ± 1.11 vs 1.13 ± 1.68 (P = 0.0178), and 4.04 ± 1.81, respectively. The ICU stay was 5.74 ± 11.49 days in group A, 6.97 ± 11.61 days (P = 0.04476) in group B, and 3.5 ± 1.11 days in group C. The postoperative hospital stay was 12.08 ± 11.28 days vs 12.93 ± 10.73 days vs 12.25 ± 2.5 days (P > 0.05) in group A vs group B vs group C. Inhospital mortality was 3% vs 3% vs 2.8% (P = 0.8038) in the three groups. Simple prediction of mortality in case of readmission to the intensive care unit A Klimasauskas, G Kekstas Vilnius University Hospital ‘Santariskiu Clinics’, Vilnius, Lithuania Critical Care 2007, 11(Suppl 2):P469 (doi: 10.1186/cc5629) Simple prediction of mortality in case of readmission to the intensive care unit A Klimasauskas, G Kekstas Vilnius University Hospital ‘Santariskiu Clinics’, Vilnius, Lithuania Critical Care 2007, 11(Suppl 2):P469 (doi: 10.1186/cc5629) Introduction Mortality of patients readmitted to the ICU is significantly higher than the mortality of patients treated once in the ICU. A simple method to predict mortality of patients readmitted to the ICU could help to select the most seriously ill readmitted patients. Table 1 (abstract P467) –24 hours 6 hours 24 hours 48 hours (preoperative) (day of (first post- (second post- operation) operative day) operative day) Group A 0.23 0.33 0.34 0.56 Group C 0.25 0.75 1.07 0.88 Methods Adult patients that were admitted to all three ICUs of the same hospital twice or more times during the same stay in the hospital during a 3-year period were retrospectively selected. The sex and age of surviving and nonsurviving readmitted patients were compared. The mortality rate of patients readmitted into the ICU during 24 and 48 hours was compared with the mortality rate of all readmitted ICU patients. The mortality of patients that were readmitted more than once into the ICU was compared with the mortality of patients that were readmitted once. P467 Sequential Organ Failure Assessment score and procalcitonin serum concentrations in patients with systolic heart failure early after cardiac surgery Methods Intensive care medical records between 2002 and 2005 of 242 patients (151 males and 91 females) who attended our ICU for 48 hours or more and proceeded mortally were analyzed retrospectively. Patients were subdivided into three groups according to the time at which mortality occurred: Group 1 08:00 a.m.–16:00 p.m., Group 2 16:00–24:00 p.m. and Group 3 00:00–08:00 a.m. Patients were also subdivided into two groups according to the days on which they died being the weekend and a weekday. The age, gender, primary diagnosis, ICU stay and mechanical ventilator times, APACHE II, Glasgow Coma Scale and SOFA scores, and mortality ratios of patients were taken and compared according to the time period. V Maravic-Stojkovic1, T Spasic1, M Jovic1, M Borzanovic1, B Djukanovic1, D Brunner2 1Dedinje Cardiovascular Institute, Belgrade, Serbia; 2Interlight, Lozana, Swaziland Critical Care 2007, 11(Suppl 2):P467 (doi: 10.1186/cc5627) V Maravic-Stojkovic1, T Spasic1, M Jovic1, M Borzanovic1, B Djukanovic1, D Brunner2 1Dedinje Cardiovascular Institute, Belgrade, Serbia; 2Interlight, Lozana, Swaziland Critical Care 2007, 11(Suppl 2):P467 (doi: 10.1186/cc5627) Introduction Previously we investigated the clinical course of patients with good left ventricle ejection fraction (EF) by assessing the Sequential Organ Failure Assessment (SOFA) score and procalcitonin (PCT) level early after cardiac surgery. In this study we included patients with systolic heart failure (HF), prospectively collecting data: B-type natriuretic peptide (BNP), PCT, and SOFA score. Results No statistically significant difference among the three groups was found in terms of age, gender, primary diagnosis, ICU stay and mechanical ventilator times, and APACHE II, Glasgow Coma Scale and SOFA scores. Also no statistically significant difference was found between mortalities during the weekend and a weekday. Conclusion A well-organized ICU can work functionally during the night-time, change of shifts and weekend. In this situation, for optimal performance, the structure and management of organization come into prominence. Our results show that in ICU patients mortality is not related to time of day when optimum situations are provided. Methods Two hundred and seventy-five patients (subjected to coronary artery bypass grafting, valve reconstruction or combined operations) were divided into three groups: echocardiographically estimated EF > 30% for the PCT group (group A, n = 102), the control group (group B, n = 103), and patients with EF < 30% for BNP analysis (group C, n = 70). PCT was measured pre- operatively, 6 hours, 24 hours and 48 hours postoperatively. P467 Sequential Organ Failure Assessment score and procalcitonin serum concentrations in patients with systolic heart failure early after cardiac surgery The SOFA score was assessed daily as SOFA1, SOFA2, SOFA3. BNP was measured preoperatively in patients with HF. P465 Conclusion In ICU patients, the cumulative area under the lactate curve correlates with the ICU LOS, cumulative SOFA score, and inhospital mortality. The prognostic value of cum-lactate requires prospective evaluation. S185 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin P468 Results A total of 13,343 patients were admitted. Eight hundred and fifty-six patients were readmitted, 172 readmitted patients died in the hospital (hospital mortality – 20.09%). The readmission rate of men was higher in comparison with women (550 vs 306 patients). The mortality of readmitted men was lower than the mortality of readmitted woman; 77 men (17.2%) died vs 95 (25.1%) women (P = 0.00001). The age of 565 patients was lower than 70 years. The mortality of readmitted patients with age lower than 70 years was lower than the mortality of patients older than 70 years; 103 (18.2%) patients younger than 70 years died vs 70 (24%) patients older than 70 years (P = 0.00001). Mortality of patients that were readmitted during 24 or 48 hours was bigger than the mortality of all readmitted patients (26.9% and 25.11% vs The relationship between mortality and its time of day in intensive care unit patients T Adanir, A Sencan, N Atasoy, M Aksun, N Karahan Izmir Ataturk Training and Research Hospital, Izmir, Turkey Critical Care 2007, 11(Suppl 2):P468 (doi: 10.1186/cc5628) P469 The duration of stay in other departments before readmission into the ICU of survivors was compared with duration of stay in other departments of nonsurvivors. Discussion We have found that the SOFA3 score had a predicting value in the mortality rate as well as PCT concentrations measured 48 hours after surgical intervention. Comparison of intensive care unit mortality performances: standardized mortality ratio vs absolute risk reduction Comparison of intensive care unit mortality performances: standardized mortality ratio vs absolute risk reduction Comparison of intensive care unit mortality performances: standardized mortality ratio vs absolute risk reduction Methods Five hundred and twenty-three tacrolimus blood concentration levels, together with 35 other relevant variables from 56 liver transplantation patients between 2002 and 2006, were extracted from Ghent University Hospital database (ICU Information System IZIS) (Centricity Critical Care Clinisoft; GE Healthcare). Multiple linear regression, and support vector regression with linear and nonlinear (RBF) kernel functions were performed, after selection of relevant data components and model parameters. Performances of the prediction models on unseen datasets were analyzed with fivefold cross-validation. Wilcoxon signed-rank analysis was performed to examine differences in performances between prediction models and to analyze differences between real and predicted tacrolimus blood concentrations. B Afessa, M Keegan, J Naessens, O Gajic Mayo Clinic College of Medicine, Rochester, MN, USA Critical Care 2007, 11(Suppl 2):P470 (doi: 10.1186/cc5630) Introduction The aim of this study was to assess the role of absolute risk reduction (ARR) to measure ICU performance as an alternative to the standardized mortality ratio (SMR). Methods This retrospective study involves patients admitted to three ICUs of a single tertiary medical center from January 2003 through December 2005. Only the first ICU admission of each patient was included in the study. The ICUs were staffed similarly. We abstracted data from the APACHE III database. For each ICU, the SMR and ARR with their 95% confidence intervals (CI) were calculated. ICU performance was categorized as shown in Table 1. When comparing ICUs, if the 95% CI of the SMR or the ARR overlap between the units, the performances were considered similar. If there was no overlap, the differences in performance were considered statistically significant. Results The mean absolute difference with the measured tacrolimus blood concentration in the predicted regression model was 2.34 ng/ml (SD 2.51). Linear SVM and RBF SVM prediction models had mean absolute differences with the measured tacrolimus blood concentration of, respectively, 2.20 ng/ml (SD 2.55) and 2.07 ng/ml (SD 2.16). These differences were within an acceptable clinical range. Statistical analysis demonstrated significant better performance of linear (P < 0.001) and nonlinear (P = 0.002) SVM (Figure 1) in comparison with linear regression. P471 20.09%; P = 0.045 and P = 0.097). The mortality of patients that were readmitted more than once (from a total 160 patients, 41 died – 25.6%) was bigger than the mortality of patients readmitted just once (from a total 696 patients, 131 died – 18.96%) (P = 0.12). The length of stay of nonsurviving readmitted patients in other departments before readmission was higher than the length of stay of survivors (mean 7.64 days vs mean 5.71 days). Conclusion Sex and age older than 70 years of patients readmitted to the ICU, readmission during 24 hours, and length of stay in other departments before readmission could be used for simple prediction of mortality of patients readmitted into the ICU. The amount of single patient readmissions to the ICU cannot be used as a predictor of death of patients readmitted to the ICU. 20.09%; P = 0.045 and P = 0.097). The mortality of patients that were readmitted more than once (from a total 160 patients, 41 died – 25.6%) was bigger than the mortality of patients readmitted just once (from a total 696 patients, 131 died – 18.96%) (P = 0.12). The length of stay of nonsurviving readmitted patients in other departments before readmission was higher than the length of stay of survivors (mean 7.64 days vs mean 5.71 days). Conclusion Sex and age older than 70 years of patients readmitted to the ICU, readmission during 24 hours, and length of stay in other departments before readmission could be used for simple prediction of mortality of patients readmitted into the ICU. The amount of single patient readmissions to the ICU cannot be used as a predictor of death of patients readmitted to the ICU. Prediction of the tacrolimus blood concentration in liver transplantation patients with support vector regression during an intensive care unit stay T Verplancke1, S Van Looy2, F De Turck2, D Benoit1, E Hoste1, G Van Maele1, S Van Hoecke2, J Decruyenaere1 1Ghent University Hospital, Ghent, Belgium; 2Ghent University, Ghent, Belgium Critical Care 2007, 11(Suppl 2):P471 (doi: 10.1186/cc5631) Introduction The tacrolimus blood concentration has wide intra- individual and inter-individual variability, especially in the initial phase after transplantation in the ICU. To insure clinical effect and to avoid side-effects, it is crucial to monitor concentrations very carefully. Prediction models can save time and resources, enabling clinicians and nurses to improve clinical care. The relationship between mortality and its time of day in intensive care unit patients The relationship between mortality and its time of day in intensive care unit patients T Adanir, A Sencan, N Atasoy, M Aksun, N Karahan Izmir Ataturk Training and Research Hospital, Izmir, Turkey Critical Care 2007, 11(Suppl 2):P468 (doi: 10.1186/cc5628) T Adanir, A Sencan, N Atasoy, M Aksun, N Karahan Izmir Ataturk Training and Research Hospital, Izmir, Turkey Critical Care 2007, 11(Suppl 2):P468 (doi: 10.1186/cc5628) Introduction It has been known that a lot of factors are effective on mortality in ICU. In terms of ICU organization it has also been known that staff might be effective on mortality and morbidity. The aim of our study is to compare the cases in terms of significant time periods that are followed and lost in the ICU. S186 Available online http://ccforum.com/supplements/11/S2 Comparison of intensive care unit mortality performances: standardized mortality ratio vs absolute risk reduction Moreover, the nonlinear RBF SVM required only seven data components to perform this prediction, compared with 10 and 12 Results During the study period, 12,447 patients were admitted to the three ICUs: 4,334 to the medical ICU, 3,275 to the mixed ICU and 4,838 to the surgical ICU. The predicted mortality rates were 19.5%, 16.0% and 9.0% and the observed mortality rates 14.8%, 9.7% and 4.3% for the medical, mixed and surgical ICUs, respectively. The SMR and ARR in mortality for each ICU are presented in Table 2. S187 p y y presented in Table 2. Conclusions ICU mortality performances assessed by SMR and ARR give different results. The ARR may be a better metric when comparing ICUs with a different case mix. Table 1 (abstract P470) Performance SMR, 95% CI ARR, 95% CI Poor >1 <0 Average Includes 1 Includes 0 Good <1 >0 Table 2 (abstract P470) ICU SMR, 95% CI ARR, 95% CI Medical 0.76, 0.70–0.82 4.7%, 3.1–6.3 Mixed 0.61, 0.54–0.68 6.3%, 4.7–7.9 Surgical 0.48, 0.41–0. 4.7%, 3.7–5.7 Figure 1 (abstract P471) S187 Figure 1 (abstract P471) S187 Figure 1 (abstract P471) Figure 1 (abstract P471) P471 The performance of linear and nonlinear support vector machines (SVM) as prediction models for the tacrolimus blood concentration in liver trans- plantation patients is compared with linear regression analysis. P470 Comparison of intensive care unit mortality performances: standardized mortality ratio vs absolute risk reduction B Afessa, M Keegan, J Naessens, O Gajic Mayo Clinic College of Medicine, Rochester, MN, USA Critical Care 2007, 11(Suppl 2):P470 (doi: 10.1186/cc5630) Figure 1 (abstract P471) We wished to examine the effect of BSD on the endothelin (ET) axis. components needed, respectively, by multiple linear regression and linear SVM. of poor postoperative outcome in lung transplantation and may cause primary graft dysfunction (PGD). A number of processes are thought to contribute to PGD. Relatively little is understood of the role of brain stem death (BSD) in subsequent organ dysfunction. We wished to examine the effect of BSD on the endothelin (ET) axis. Methods Following ethics approval, 14 Wistar–Kyoto rats were anaesthetised, with tracheostomy and arterial and venous cannulation. A 200 µl Fogarty’s balloon catheter was inserted via a burr hole into the subdural vault. The balloon was inflated in the experimental group but not the control group. Four hours of positive pressure ventilation were followed by euthanasia and organ retrieval. Lung tissue was stained for H&E for morphology, and alveolar macrophages (AM) were identified by anti-CD68 staining. AM were stained with a monoclonal anti-ET-1 antibody, as well as the polyclonal anti-ET-A and ET-B. Results All animals survived the experiment. There was a significant increase in the ratio of AM to neutrophils (P = 0.002). The ET-1 content on the AM was significantly increased in the experimental group (27.57 ± 5.26 vs 7.01 ± 1.75, P < 0.0001). Conclusions In this model, BSD was associated with an increase in the ratio of AM to neutrophils, and there was significant upregulation of the endothelin axis on these AM, as evidenced by raised levels of ET-1, ET-A and ET-B. There may be a role for endothelin blockade in the BSD organ donor. This may increase the yield of organs that can be accepted for transplantation and improve early graft function in the recipient Conclusion Performance of SVM with linear and nonlinear kernel function was excellent and superior in comparison with the multiple linear regression model in predicting the tacrolimus blood concentration. Methods Following ethics approval, 14 Wistar–Kyoto rats were anaesthetised, with tracheostomy and arterial and venous cannulation. A 200 µl Fogarty’s balloon catheter was inserted via a burr hole into the subdural vault. The balloon was inflated in the experimental group but not the control group. Four hours of positive pressure ventilation were followed by euthanasia and organ retrieval. Lung tissue was stained for H&E for morphology, and alveolar macrophages (AM) were identified by anti-CD68 staining. Figure 1 (abstract P471) AM were stained with a monoclonal anti-ET-1 antibody, as well as the polyclonal anti-ET-A and ET-B. P474 Prognosis factors in lung transplant recipients readmitted to the intensive care unit B Suberviola, A Gonzalez Castro, J Llorca, A Vallejo, C Gonzalez Mansilla, E Miñambres Hospital Universitario Marques de Valdecilla, Santander, Spain Critical Care 2007, 11(Suppl 2):P474 (doi: 10.1186/cc5634) B Suberviola, A Gonzalez Castro, J Llorca, A Vallejo, C Gonzalez Mansilla, E Miñambres Hospital Universitario Marques de Valdecilla, Santander, Spain Critical Care 2007, 11(Suppl 2):P474 (doi: 10.1186/cc5634) Introduction The short-term survival after lung transplantation has improved gradually. Despite this the peritransplant period is of high risk. Factors influencing the readmission of lung transplant recipients to the ICU are diverse, but respiratory failure and sepsis are the predominant causes. The objective of our study was to identify outcome predictors and prognostic factors for survival Results Eighty-seven per cent (n = 69) of kidneys transplanted from optimal donors, in fact, have turned out working, 4% (n = 3) have re-entered haemodialysis within 5 years from the surgery, and only 9% (n = 7) have deceased in the same period. Regarding marginal kidney receiving, it has been possible to demonstrate that 72% (n = 52) of such subjects maintained a good function of the transplant, 11% (n = 8) re-entered haemodialysis, and 17% passed away within 5 years of the transplant. among lung transplant recipients on readmission to the ICU. Materials and methods A retrospective study of all lung transplant recipients achieved during a 10-year period (from 1997 to 2006). Data collection included the age, gender, reason for and type of lung transplantation. Variables specific to individual ICU admissions included the admission diagnosis, length of stay, duration of mechanical ventilation, interval time from transplan- tation, Acute Physiology and Chronic Health Evaluation (APACHE) II score on ICU admission, and the identification of systemic organ dysfunction. We used Student’s t test (or, where appropriate, its nonparametric equivalent) or the χ2 test for comparisons among the patients who died and the patients who survived their ICU admissions. Conclusions The difference between the survival of the two receiving groups is not such to justify the exclusion of marginal donors from the ‘pool’ of potential kidney donors. Considering that, the use of marginal donors can be a valid system in order to supply the lack of organs. Moreover the histological examinations, executed on patterns captured with wedge biopsy before the transplant, can be an effective strategy finalized for the expansion of potential kidney donors. P472 Effects of the clinical characteristics of the organ donor on the long-term results of the transplant and survival of the patient, with particular reference to kidney transplants S Pirri, R Mastrandrea, A Barcia, A Mazzola, S Salemi University of Palermo, Italy Critical Care 2007, 11(Suppl 2):P472 (doi: 10.1186/cc5632) Results All animals survived the experiment. There was a significant increase in the ratio of AM to neutrophils (P = 0.002). The ET-1 content on the AM was significantly increased in the experimental group (27.57 ± 5.26 vs 7.01 ± 1.75, P < 0.0001). Introduction To assess the role of the single clinical parameters of the donor on the outcome of the transplant and the variability of this in relation to the state of an optimal or borderline donor. Conclusions In this model, BSD was associated with an increase in the ratio of AM to neutrophils, and there was significant upregulation of the endothelin axis on these AM, as evidenced by raised levels of ET-1, ET-A and ET-B. There may be a role for endothelin blockade in the BSD organ donor. This may increase the yield of organs that can be accepted for transplantation and improve early graft function in the recipient. Methods One hundred and fifty-one receiving and deceased donor brace subordinates to kidney transplant. Clinical parameters investigated for every donor were: age, arterial hypertension (≥140/80 mmHg), diabetes, blood values of creatinine. It was chosen to classify as marginal all the donors with age >55 years, and/or hypertension, and/or diabetes, and/or with blood values of creatinine >1.5 mg/dl, and/or whose death has happened because of one whichever pathology that has determined cerebral anoxia. Based on such parameters the donors’ borderline was 72/151 (47.7%), while the optimal was 79/151 (52.3%). The mean age of the donors was 47.5 years (range 14–81 years). The population of the 151 receiving optimal and marginal kidneys was constituted of patients judged suitable for the transplant with typical risk factors for a standard population of subjects on dialysis. The mean age of receiving patients was 46 years (range 21–71 years). We have classified receiving based on the outcome of the transplant to 5 years, as: patients alive with transplanted kidney still working, deceased patients, and patients re-entered to haemodialysis. Figure 1 (abstract P471) Conclusions ICU mortality performances assessed by SMR and ARR give different results. The ARR may be a better metric when comparing ICUs with a different case mix. Table 1 (abstract P470) Performance SMR, 95% CI ARR, 95% CI Poor >1 <0 Average Includes 1 Includes 0 Good <1 >0 Table 2 (abstract P470) ICU SMR, 95% CI ARR, 95% CI Medical 0.76, 0.70–0.82 4.7%, 3.1–6.3 Mixed 0.61, 0.54–0.68 6.3%, 4.7–7.9 Surgical 0.48, 0.41–0. 4.7%, 3.7–5.7 S187 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin of poor postoperative outcome in lung transplantation and may cause primary graft dysfunction (PGD). A number of processes are thought to contribute to PGD. Relatively little is understood of the role of brain stem death (BSD) in subsequent organ dysfunction. We wished to examine the effect of BSD on the endothelin (ET) axis. Methods Following ethics approval, 14 Wistar–Kyoto rats were anaesthetised, with tracheostomy and arterial and venous cannulation. A 200 µl Fogarty’s balloon catheter was inserted via a burr hole into the subdural vault. The balloon was inflated in the experimental group but not the control group. Four hours of positive pressure ventilation were followed by euthanasia and organ retrieval. Lung tissue was stained for H&E for morphology, and alveolar macrophages (AM) were identified by anti-CD68 staining. AM were stained with a monoclonal anti-ET-1 antibody, as well as the polyclonal anti-ET-A and ET-B. Results All animals survived the experiment. There was a significant increase in the ratio of AM to neutrophils (P = 0.002). The ET-1 content on the AM was significantly increased in the experimental group (27.57 ± 5.26 vs 7.01 ± 1.75, P < 0.0001). Conclusions In this model, BSD was associated with an increase in the ratio of AM to neutrophils, and there was significant upregulation of the endothelin axis on these AM, as evidenced by raised levels of ET-1, ET-A and ET-B. There may be a role for endothelin blockade in the BSD organ donor. This may increase the yield of organs that can be accepted for transplantation and improve early graft function in the recipient. of poor postoperative outcome in lung transplantation and may cause primary graft dysfunction (PGD). A number of processes are thought to contribute to PGD. Relatively little is understood of the role of brain stem death (BSD) in subsequent organ dysfunction. P475 Predictors of intensive care unit readmission within 48 hours after discharge E Boudesteijn, S Arbous, P Berg van den LUMC, Leiden, The Netherlands Critical Care 2007, 11(Suppl 2):P475 (doi: 10.1186/cc5635) Methods From February 1996 until May 2006 we studied all LT patients from a single centre initially discharged from the ICU who needed to be readmitted. Demographic data included the type and date of LT, best post-LT FEV1, last pre-ICU readmission FEV1, admission diagnosis, time from LT to ICU admission, mechanical ventilation (MV) use, rejection episodes and infections. Actuarial survival rates (ASR) were calculated with Kaplan–Meier curves. Introduction Readmission to the ICU during the same hospitalization is associated with significant morbidity and mortality and results in a longer length of stay and higher costs. There is therefore growing interest to identify reliable predictors for readmission. The aim of our study was to assess the incidence of ICU readmissions, identify predictors of ICU readmission, and determine patient outcome. Results A total of 103 LT patients were discharged from the ICU, 41 patients (39.8%) were readmitted (males 53.6% (22 patients) with a mean age of 42 years (15–66)). Indications were emphy- sema in 13 patients (31.7%), idiopathic pulmonary fibrosis in eight patients (19.5%), bronchiectasis in five patients (12.2%), cystic fibrosis in five patients and others in seven patients (17%). Seventeen patients underwent bilateral LT, 11 patients right LT (26.8%) and eight patients left LT (19.5%), while five patients received a heart–lung transplantation. Respiratory failure was the principal ICU admission diagnosis (68.3%), followed by seizures (7%) and septic shock (4.8%). MV was required in 35 patients (85.3%). ICU mortality for readmitted patients was 68.3% with a 1-year, 3-year and 5-year ASR of 67.3%, 62.9% and 47.4%. The survival median was 1,761 days (1,134–2,388). In the MV patients, a 1-year, 3-year and 5-year ASR of 63.1%, 58.9% and 44.2% was found with a median survival of 1,618 days (132–3,104). The time to ICU admission was 1,303 (4–3,096 days). ICU admission timing was not found to be a predictor for early (<30 days; 53.8%) vs late (>30 days: 46.4%), P = 0.65. Deceased patients required significantly more MV (71.4% vs 38.5%; P = 0.044 (chi-square); OR: 4; 95% CI: 1–15.99). Emphysema was not more prevalent in the deceased patient group, and neither was the pre-ICU readmission FEV1 nor the occurrence of opportunistic infections. Steroid-resistant acute rejection was found to correlate with mortality. P475 Methods We performed a retrospective case–control study. The study population consisted of all patients who were discharged alive from our 28-bed surgical, thoracic–surgical and medical ICU in a university teaching hospital in a 1-year period. A case was defined as a patient readmitted to the ICU within 48 hours after discharge. For each case, three control patients were randomly selected from the study population. The following information was collected: demographic parameters and APACHE II score, parameters of hemodynamic, respiratory and renal function, length of ICU stay, duration of invasive ventilatory support (ventilator time), and time between extubation and discharge. To determine a predictive model, covariate selection was done by the two-sample t test, Mann–Whitney test and univariate logistic regression. From significant (P < 0.10), plausible and clinically relevant variables, a predictive model was generated using multivariate logistic regression. Results During a 1-year period 1,635 patients were admitted to our ICU. Of 1,393 patients at risk for readmission, 25 (1.8%) readmissions occurred in 23 patients. Nine of the 23 (39%) readmitted patients died during their hospitalization, while the overall ICU mortality was 10.6%. The most important reason for readmission (68% of the cases) was respiratory deterioration. In the univariate analysis, age, ventilator time during first admission and time between extubation and ICU discharge were significant predictors of readmission. In the multivariate analysis, age (OR 1.1; 95% CI 1.00–1.13; P = 0.03) and ventilator time during first admission (OR 1.1; 95% CI 1.00–1.10; P = 0.03) were significant predictors, corrected for patient characteristics. Furthermore, patients who were readmitted had a significant longer duration of total (first and second admission) ventilator time (188 vs 106 hours, P = 0.012), and total ICU stay (400 vs 127 hours, P = 0.009). Conclusion Patients readmitted to the ICU have significant longer overall ventilator time, ICU stay, and a higher ICU mortality. The ventilator time during first admission (especially beyond 300 hours) is an important predictor of readmission. The time it takes to get patients ready for discharge after extubation also differed significantly. The data suggest that elderly patients who have been ventilated for a long period are at particular risk for readmission and should receive additional care before discharge from the ICU. Results During a 1-year period 1,635 patients were admitted to our ICU. Of 1,393 patients at risk for readmission, 25 (1.8%) readmissions occurred in 23 patients. Upregulation of the endothelin axis in alveolar macrophages following brain stem death in a murine model Upregulation of the endothelin axis in alveolar macrophages following brain stem death in a murine model Results A total of 144 lung transplants were performed at our institution. Forty-six of them died on the ICU during the immediate perioperative period. Finally, 98 were discharged from the ICU. Twenty-eight patients were readmitted to the ICU after discharge (28.57%). The mean of age was 51.3 ± 11.6 years. The male/female ratio was 23/5. The mean period transcurred between ICU discharge and ICU readmission was 107 ± 162 days. The admission diagnosis was sepsis in 20 cases (71.4%). Seventeen patients died during the ICU stay (60.7%). We found that an J Fraser, A Sutherland, F Kermeen, K McNeil, J Dunning The Prince Charles Hospital, Brisbane, Australia Critical Care 2007, 11(Suppl 2):P473 (doi: 10.1186/cc5633) Introduction Outcomes post lung transplantation continue to improve, but early pulmonary dysfunction dictates long-term morbidity and mortality. Ischaemia reperfusion injury is a precipitant Introduction Outcomes post lung transplantation continue to improve, but early pulmonary dysfunction dictates long-term morbidity and mortality. Ischaemia reperfusion injury is a precipitant S188 Available online http://ccforum.com/supplements/11/S2 P476 increase in APACHE II score, delay to ICU readmission, need of mechanical ventilation and three or more organ dysfunctions were significantly associated with mortality. Intensive care unit readmissions after lung transplantation: epidemiology and outcome Intensive care unit readmissions after lung transplantation: epidemiology and outcome Conclusions Admission to the ICU is common in lung transplant recipients, and it is associated with a high mortality. Sepsis is the main cause of ICU readmission and the most frequent cause of death. Lung transplant recipients with higher APACHE II score and three or more organ dysfunction present higher mortality. The delay on ICU readmission is also associated with higher mortality. F Klein, P Klin, J Osses, J Díaz, A Bertolotti, R Favaloro Favaloro Foundation, Buenos Aires, Argentina Critical Care 2007, 11(Suppl 2):P476 (doi: 10.1186/cc5636) Introduction Significant improvement of short-term and long-term survival after lung transplantation (LT) has been observed. Never- theless, a significant number of patients need to be readmitted to the ICU. The aim of our study was to analyse the epidemiology, outcome and risk factors for LT patients readmitted to the ICU after an initial discharge. P475 Nine of the 23 (39%) readmitted patients died during their hospitalization, while the overall ICU mortality was 10.6%. The most important reason for readmission (68% of the cases) was respiratory deterioration. In the univariate analysis, age, ventilator time during first admission and time between extubation and ICU discharge were significant predictors of readmission. In the multivariate analysis, age (OR 1.1; 95% CI 1.00–1.13; P = 0.03) and ventilator time during first admission (OR 1.1; 95% CI 1.00–1.10; P = 0.03) were significant predictors, corrected for patient characteristics. Furthermore, patients who were readmitted had a significant longer duration of total (first and second admission) ventilator time (188 vs 106 hours, P = 0.012), and total ICU stay (400 vs 127 hours, P = 0.009). Conclusion ICU readmissions are frequent among LT patients. In our study group, respiratory failure was the more prevalent admission diagnosis. The need for MV was associated with a worse prognosis as well as steroid-resistant acute rejection episodes. Early or late ICU admission after LT has not influenced mortality. P478 One-year survival of patients admitted to the neurological intensive care unit M Puntis, H Robertshaw St George’s Hospital, London, UK Critical Care 2007, 11(Suppl 2):P478 (doi: 10.1186/cc5638) One-year survival of patients admitted to the neurological intensive care unit M Puntis, H Robertshaw St George’s Hospital, London, UK Critical Care 2007, 11(Suppl 2):P478 (doi: 10.1186/cc5638) One-year survival of patients admitted to the neurological intensive care unit M Puntis, H Robertshaw St George’s Hospital, London, UK Critical Care 2007, 11(Suppl 2):P478 (doi: 10.1186/cc5638) p y Method Approval for the study was granted by the local ethics committee. We reviewed MEWS scores from all patients (n = 2,974) admitted to a six-bed medical and surgical adult HDU in a general hospital from July 2002 to October 2005. The MEWS score was calculated from observations of heart rate, blood pressure, respiratory rate, urine output, conscious level and temperature recorded within 24 hours of admission to the HDU. Results Of the 2,974 patients reviewed, 2,447 patients had sufficient data. Analysis using logistic regression shows a strong relationship between the probability of death and the MEWS score: the odds of death increase by 1.48 (confidence interval 1.41–1.56; P < 0.001) for each unit increase in the MEWS score. However, there is no reason that these data should follow a logistic form and the estimates of uncertainty around the point estimates from logistic regression are poor. More accurate estimates of the death rate for each of the MEWS scores were achieved using a ‘bootstrapping’ technique (repeated sampling, with replacement, from the dataset) 1,000 times (see Figure 1). The median death rate (%) for each MEWS score was: 3 = 1.5%; 4 = 0.7%; 5 = 2.2%; 6 = 3.0%; 7 = 3.0%; 8 = 5.6%; 9 = 9.7%; 10 = 13.3%; 11 = Method Approval for the study was granted by the local ethics committee. We reviewed MEWS scores from all patients (n = 2,974) admitted to a six-bed medical and surgical adult HDU in a general hospital from July 2002 to October 2005. The MEWS score was calculated from observations of heart rate, blood pressure, respiratory rate, urine output, conscious level and temperature recorded within 24 hours of admission to the HDU. Introduction Patient survival in neurological intensive care units (NICUs) may be obvious; however, there is currently little evidence regarding the longer term outcome of these patients. Use of a modified early warning system to predict outcome in patients admitted to a high dependency unit Use of a modified early warning system to predict outcome in patients admitted to a high dependency unit Conclusion Survival rates among those readmitted are high. Those returning from the HDU represent a cohort at higher risk of mortality. The functional status after 2.5 years varies particularly with the timing of readmission, readmission diagnosis and APACHE score at readmission. C Carle, C Pritchard, S Northey, J Paddle Royal Cornwall Hospital, Truro, UK Critical Care 2007, 11(Suppl 2):P479 (doi: 10.1186/cc5639) C Carle, C Pritchard, S Northey, J Paddle Royal Cornwall Hospital, Truro, UK C Carle, C Pritchard, S Northey, J Paddle Royal Cornwall Hospital, Truro, UK Critical Care 2007, 11(Suppl 2):P479 (doi: 10.1186/cc5639) Introduction The modified early warning system (MEWS) is a physiological scoring system that identifies patients at risk of deterioration who require increased levels of care [1]. The use of a patient’s MEWS score to predict outcome in a high-dependency unit (HDU) has not been previously described. P478 In this study the 1-year survival of NICU patients has been defined. Introduction Patient survival in neurological intensive care units (NICUs) may be obvious; however, there is currently little evidence regarding the longer term outcome of these patients. In this study the 1-year survival of NICU patients has been defined. p Results Of the 2,974 patients reviewed, 2,447 patients had sufficient data. Analysis using logistic regression shows a strong relationship between the probability of death and the MEWS score: the odds of death increase by 1.48 (confidence interval 1.41–1.56; P < 0.001) for each unit increase in the MEWS score. However, there is no reason that these data should follow a logistic form and the estimates of uncertainty around the point estimates from logistic regression are poor. More accurate estimates of the death rate for each of the MEWS scores were achieved using a ‘bootstrapping’ technique (repeated sampling, with replacement, from the dataset) 1,000 times (see Figure 1). The median death rate (%) for each MEWS score was: 3 = 1.5%; 4 = 0.7%; 5 = 2.2%; 6 = 3.0%; 7 = 3.0%; 8 = 5.6%; 9 = 9.7%; 10 = 13.3%; 11 = Methods Between April 2004 and April 2005, all patients admitted to the NICU requiring ≥24 hours of ≥2 organ system support were identified (n = 175). The year following admission was divided into three phases – early (0–30 days), middle (31–90 days) and late (91–360 days) – and mortality was recorded. Data were analysed using Kaplan–Meier and log-rank analysis. Results Patients were admitted from many sources; interhospital transfers (n = 90), neurosurgical admissions (n = 26), medical admissions (n = 36), and emergency admissions (n = 15). Reasons for admission included haemorrhage (n = 66), trauma (n = 52) and neoplasm (n = 19). Ninety-one patients (52.0%) spent less than 7 days on the NICU and 84 (48%) required ≥7 days. Overall survival was 70.9% at 30 days and 61.1% at 1 year. There was no significant variation between the young (<60 years) and older (≥60 years) groups (62.6%, n = 115 vs 58.3%, n = 60, P > 0.5). Nor was there a difference between those receiving two organ support and those receiving ≥3 organ support (62.1%, n = 66 vs P477 The functional outcome of patients requiring intensive care readmission N Conlon, B O’Brien, B Marsh Mater Misericordiae University Hospital, Dublin, Ireland Critical Care 2007, 11(Suppl 2):P477 (doi: 10.1186/cc5637) N Conlon, B O’Brien, B Marsh Mater Misericordiae University Hospital, Dublin, Ireland Critical Care 2007, 11(Suppl 2):P477 (doi: 10.1186/cc5637) Conclusion Patients readmitted to the ICU have significant longer overall ventilator time, ICU stay, and a higher ICU mortality. The ventilator time during first admission (especially beyond 300 hours) is an important predictor of readmission. The time it takes to get patients ready for discharge after extubation also differed significantly. The data suggest that elderly patients who have been ventilated for a long period are at particular risk for readmission and should receive additional care before discharge from the ICU. Introduction Rates of readmission to the ICU are often cited as controversial indices of quality of intensive care, adequacy of follow-up and as guides to resource allocation. Nonetheless there are few data on the long-term functional outcome of ICU recidivists: we set out to study this. S189 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Methods With ethical approval, from a prospectively collected database of all ICU admissions from 2004, we identified all readmissions to our ICU from within the hospital. We identified survivors from the database, and contacted them, 2–3 years later, to assess their functional outcome, as the Glasgow Outcome Score (GOS) and Karnofsky score. 60.6%, n = 109, P > 0.5). Mortality (deaths/30 days) varied dramatically between the early, middle and late phases (29.1% vs 3.2% vs 0.9%, P < 0.001). Conclusions Although mortality is high during the first 30 days of neurological critical illness there is a significant plateau in the survival curve; patients surviving beyond the initial phase tend to survive long term. Larger studies may be beneficial to further evaluate subgroup variation in the survival curve profile. Results Of 97 readmissions, 79 (81%) survived the ICU. Most of them (57%) came from the high-dependency unit (HDU), of whom 74% survived. Thirty-three per cent came from other wards and 10% from theatre: 90% of each of these groups survived the ICU. Further data on these groups’ interim survival and functional outcomes are presented. Changes of the system of postoperative care decreases mortality in a surgical unit 2), were selected for comparative analysis. The selection was dictated by a few reasons. The Medical University in Lodz is the founding body of all hospitals subjected to analysis. These hospitals are only a few kilometres away from each other. The units have a similar number of beds, and well-educated medical and nursing staff. Heads of the hospital departments have all been awarded a professorship. Health benefits are provided on the basis of the same list of benefits as part of contract with the same payer – Lodz Provincial Branch of the National Health Fund. Methods A prospective descriptive analysis of OCC in four SDUs (18 beds) with an open model of care in a tertiary regional referral centre. We administered a modified version of the previously validated Shortell ICU nurse–physician questionnaire to all healthcare professionals (HCPs) and physicians caring for patients in the SDUs in May 2006. We measured opinion regarding patient safety culture, organizational practices, perceived effectiveness of practice, and job satisfaction. Responses were converted to item scores, which reflect negative to positive opinion (0–100). Scores were aggregated for each survey construct and for an overall SDU rating. Results Surveys were completed by 68 HCPs and 69 physicians. Aggregated mean ± standard deviation item scores of HCP and physician opinions were (presented as assessment area, HCPs, physicians, P value): overall OCC in SDUs, 54.8 ± 19.9, 57.0 ± 20.3, P = 0.52; patient safety culture, 52.2 ± 21.2, 50.9 ± 21.0, P = 0.72; within-group relationships, 66.5 ± 16.0, 63.7 ± 18.2, P = 0.33; between-group relationships, 53.8 ± 22.2, 62.4 ± 21.7, P = 0.02; overall leadership, 52.2 ± 19.6, 54.8 ± 18.7, P = 0.42; conflict management, 55.2 ± 20.1, 61.3 ± 20.1, P = 0.08; effectiveness of care, 54.7 ± 16.8, 55.8 ± 19.3, P = 0.72; and job satisfaction, 67.5 ± 19.0, 77.9 ± 20.3, P = 0.002. The overall OCC score and most subcategory scores were similar between HCPs and physicians. Physicians had a better opinion of their relationships with other groups and a higher job satisfaction than HCPs. Methods The study is a retrospective analysis of mortality in general surgery units located at three university teaching hospitals: UH No. 1, UH No. 2 and UH No. 5. The study comprised 25,921 patients treated in these units from 1 January 2003 to 30 June 2006. The available statistical material was analysed. P480 Introduction The purpose of this study was to examine organizational culture and climate (OCC) in step-down units (SDUs). Organizational culture is defined as the norms, values, beliefs and expectations shared by those who work in a given unit. Organizational climate is the perception of unit culture by its workers. In ICUs, organizational culture is an important determinant of the quality of care delivered. In an attempt to alleviate ICU demand and expenditures, many centers have opted to provide graded levels of critical care with the creation of SDUs. There is a paucity of literature specifically examining OCC in SDUs. Figure 1 (abstract P479) Distribution of bootstrapped estimates of death rates by MEWS score (median, interquartile and observed range). 0 Figure 1 (abstract P478) Distribution of bootstrapped estimates of death rates by MEWS score (median, interquartile and observed range). Figure 1 (abstract P478) Distribution of bootstrapped estimates of death rates by MEWS score (median, interquartile and observed range). S190 Available online http://ccforum.com/supplements/11/S2 Changes of the system of postoperative care decreases mortality in a surgical unit M Piechota1, M Banach2 1Bolesùaw Szarecki University Hospital No. 5 in Lodz, Poland; 2University Hospital No. 3 in Lodz, Poland Critical Care 2007, 11(Suppl 2):P480 (doi: 10.1186/cc5640) Introduction In 2005, 10 public health care institutions functioned in the area of Lodz, having in their structure a surgical unit classified as a general surgery unit. They were three university teaching hospitals, three provincial hospitals, three county hospitals and one departmental hospital. Mortality in university teaching hospitals having 167 beds was 1.25%, in provincial hospitals with 191 beds was 2.96%, and in county hospitals with 140 beds was 3.98%. The lowest percentage mortality was noted in the surgical unit of Bolesùaw Szarecki University Teaching Hospital No. 5 in Lodz (UH No. 5) and it was 0.35%. The authors decided to analyse the causes of such low mortality in this hospital. Two remaining university teaching hospitals, N. Barlicki University Teaching Hospital No. 1 in Lodz (UH No. 1) and WAM University Teaching Hospital No. 2 in Lodz (UH No. 2), were selected for comparative analysis. The selection was dictated by a few reasons. The Medical University in Lodz is the founding body of all hospitals subjected to analysis. These hospitals are only a few kilometres away from each other. The units have a similar number of beds, and well-educated medical and nursing staff. Heads of the hospital departments have all been awarded a professorship. Health benefits are provided on the basis of the same list of benefits as part of contract with the same payer – Lodz Provincial Branch of the National Health Fund. Introduction In 2005, 10 public health care institutions functioned in the area of Lodz, having in their structure a surgical unit classified as a general surgery unit. They were three university teaching hospitals, three provincial hospitals, three county hospitals and one departmental hospital. Mortality in university teaching hospitals having 167 beds was 1.25%, in provincial hospitals with 191 beds was 2.96%, and in county hospitals with 140 beds was 3.98%. The lowest percentage mortality was noted in the surgical unit of Bolesùaw Szarecki University Teaching Hospital No. 5 in Lodz (UH No. 5) and it was 0.35%. The authors decided to analyse the causes of such low mortality in this hospital. Two remaining university teaching hospitals, N. Barlicki University Teaching Hospital No. 1 in Lodz (UH No. 1) and WAM University Teaching Hospital No. 2 in Lodz (UH No. Organizational culture and climate in step-down units C McColl, J Muscedere, J Drover, M Squires, B Mahon, D Heyland Queen’s University, Kingston, Canada Critical Care 2007, 11(Suppl 2):P481 (doi: 10.1186/cc5641) Conclusion The MEWS score can be used as a useful predictor of outcome in a HDU. Changes of the system of postoperative care decreases mortality in a surgical unit In the first stage the statistical data were analysed by the Provincial Centre of Public Health in Lodz. The obtained information concerned the number of treated patients, the number of patients transferred, discharged or dead, the number of man-days, mean bed use, mean hospitalisation time, mean number of patients per bed and mortality. The second stage focused on explaining the reasons for significantly lower mortality among patients hospitalised in the surgical unit of UH No. 5. Among others, the structure of the hospitalised patients in each of these units was analysed, the quantity and range of a contract signed with the unit financing the benefits and internal principles of these units functioning. Conclusions Overall scores of OCC were poor and did not differ between HCPs and physicians with the exception of between- group relationships and job satisfaction. More research is needed to determine the correlation between clinical outcomes and OCC in SDUs and whether improvements in OCC result in better clinical outcomes and job satisfaction. P481 15.9%; 12 = 20.9%; 13 = 32.0%; 14 = 47.2%; 15 = 51.9%; 16 = 54.6%; 17 = 66.7%. MEWS scores of 2 or less (n = 19) had no deaths. Organizational culture and climate in step-down units Patient and family satisfaction with care in step-down units Service consequences were bed blocking/increased workload in 20%, delayed admission of another patient in 14%, cancelled elective operations in 4%, and loss of unit capacity and cohesion in 7%. Conclusions We failed to achieve 100% successful plans. Small numbers and failure to gather more than 40% of staff opinions on causes and consequences of failed plans limit this pilot study. Documentation in (electronic) notes did not improve completion of plans. The process and efficiency of care has an impact on at least aspects of morbidity and length of stay, and deserve further study. patient-centered and family-centered quality care. Literature examining patient or family satisfaction in SDUs is limited. patient-centered and family-centered quality care. Literature examining patient or family satisfaction in SDUs is limited. Methods We administered a modified version of the previously validated Family Satisfaction with ICU care survey to patients and families of patients who were cared for in the SDUs (18 beds in four separate units) of a tertiary regional referral center. We obtained self-reported levels of patient and family satisfaction with 27 aspects of care related to SDU experience, communication, and decision-making. Responses were converted to item scores, which reflect poor to excellent satisfaction with care (0–100). Methods We administered a modified version of the previously validated Family Satisfaction with ICU care survey to patients and families of patients who were cared for in the SDUs (18 beds in four separate units) of a tertiary regional referral center. We obtained self-reported levels of patient and family satisfaction with 27 aspects of care related to SDU experience, communication, and decision-making. Responses were converted to item scores, which reflect poor to excellent satisfaction with care (0–100). p Results A total of 120 patient surveys (60% response) and 99 family surveys (45% response) were completed. Patients had a mean SDU length of stay of 2.5 days, APACHE II score of 9.9 and an SDU mortality of 2.4%. The highest levels of satisfaction with care were (mean ± standard deviation item score; presented as aspect of care, patients, families, P value): overall care (aggregate score), 81.1 ± 21.5, 80.1 ± 22.3, NS; concern and caring received from SDU staff, 87.9 ± 17.1, 90.4 ± 5.0, NS; and nurses’ skill and competence, 88.7 ± 16.0, 88.8 ± 16.6, NS. Patient and family satisfaction with care in step-down units Patient and family satisfaction with care in step-down units Patient and family satisfaction with care in step-down units C McColl, J Muscedere, J Drover, M Squires, B Mahon, D Heyland Queen’s University, Kingston, Canada Critical Care 2007, 11(Suppl 2):P482 (doi: 10.1186/cc5642) Results Mortality in the general surgery unit of UH No. 5 was 0.40% within the period from 1 January 2003 to 30 June 2006. In the general surgery unit of UH No. 1 and of UH No. 2, mortality was respectively 2.70% and 2.13%. Introduction The purpose of this study was to determine the level of satisfaction of patients and families with the care received in step-down units (SDUs). In an effort to alleviate ICU demand, many centers have opted to provide graded levels of critical care in SDUs. However, there is a paucity of literature as to the effectiveness of care delivered in SDUs. Measures of patient and family satisfaction with healthcare are recognized as valuable tools for the assessment of healthcare delivery including adherence to Conclusions Changes of the system of postoperative care consisting of taking over postoperative care by physicians and anaesthesiological nurses, intensive monitoring of postoperative patients, and immediate transfer of patients with life hazard to the ICU decreases significantly the mortality in a surgical unit. S191 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin unsuccessful plans, 36 were completed late, 22 were never completed and nine had missing data. Thirty-six per cent, 34% and 18% of arbitrarily defined high-priority, medium-priority and low- priority plans were unsuccessful. Most plans were to be actioned by nurse or senior house officer, and 36% and 28% were unsuc- cessful, respectively. More unsuccessful plans than successful plans were recorded in the computerised notes, 79% vs 67%. Only 40% of data (staff opinions) on perceptions of causes and consequences were gathered. Patient consequences of failed plans included increased ICU stay in 24%, increased morbidity such as risk of inadequate nutrition in 9%, delayed definitive treat- ment in 7%, delayed weaning in 6%, increased risk of infection in 5% and no impact on patient in 44%. Consequences for family included no impact in 53%, misinformation given in 8%, delayed patient access in 2%, and delayed communication in 2%. P483 Abstract withdrawn Patient and family satisfaction with care in step-down units The lowest levels of satisfaction were: frequency of communication with physicians, 71.6 ± 27.8, 62.7 ± 32.2, P = 0.03 and decision- making (aggregate score), 67.5 ± 29.9, 62.7 ± 30.5, NS. For the decision-making process, a proportion of respondents felt they were not included (patients, families, P value; 40.3%, 42.7%, NS), not supported (31%, 38.6%, NS), and not in control (32.7%, 55.3%, P = 0.001). Patients and families were least satisfied with the frequency of communication with physicians and participation in decision-making. Patients and families were similar in their assessments with the exception of the frequency of communication with physicians and control of the care delivered. Outcome of very old patients on mechanical ventilation Outcome of very old patients on mechanical ventilation R Espinoza, R Serafim, F Gago, F Saddy, B Tura, J Castro Hospital Copa D’Or, Rio de Janeiro, Brazil Critical Care 2007, 11(Suppl 2):P485 (doi: 10.1186/cc5645) R Espinoza, R Serafim, F Gago, F Saddy, B Tura, J Castro Hospital Copa D’Or, Rio de Janeiro, Brazil Critical Care 2007, 11(Suppl 2):P485 (doi: 10.1186/cc5645) Conclusions While most patients and family members were satisfied with care received, these data identify opportunities for improvement. Specifically, attention must be paid to communication and decision-making processes in SDUs. Background The population group of 85 years old or more, classified as very old, are the most rapidly growing group in developed countries, although it still represents 0.46% of the Brazilian population. Aging is associated with decreased cardiopulmonary and renal reserve as well as the development of progressive organ failure. P484 Objective To evaluate outcomes of very old patients in mechanical ventilation. Causes and consequences of failure of implementation of management plans in critical care Causes and consequences of failure of implementation of management plans in critical care Patients and methods A prospective cohort study in the medical/surgical ICU of a tertiary-care Brazilian hospital. Two hundred and forty-four patients aged 85 years old or more were selected from 7,410 patients admitted to the ICU from October 2002 to September 2006. Data were extracted from the QUATI (Dixtal-Brazil) database and included sex, age, APACHE II score, ventilation-days, length of stay, incidence of sepsis, tracheotomy, dialysis therapy and hemodynamic monitoring. For statistical analysis we used the chi-square test for evaluated difference of proportion, and considered statistical significance as P < 0.05. Results There were 168 female (68.9%) and 75 male (30.7%) patients. The mean age of the study population and the APACHE II score were 89.55 ± 3.61 years and 17.98 ± 6.3, respectively. Median ventilation-days and length of stay were 6 and 8.14 days, respectively. Tracheotomy was performed in 44.1%, dialysis therapy in 15.2% and hemodynamic monitoring in 19.8%. Only the group above 95 years old had a significant increase of days of ventilation and length of stay: 18.77 vs 10.47 days (P = 0.01) and 19.74 vs 12.86 days (P = 0.07), respectively. The predicted APACHE II mortality for the studied population was 26.9 ± 17.21% and the present rate to the population studied was 47.7%. Patients in dialysis and with diagnosis of sepsis at admission had poorer prognosis (respectively a 1.6 and 1.52 times likely ratio to die). Patients and methods A prospective cohort study in the medical/surgical ICU of a tertiary-care Brazilian hospital. Two hundred and forty-four patients aged 85 years old or more were selected from 7,410 patients admitted to the ICU from October 2002 to September 2006. Data were extracted from the QUATI (Dixtal-Brazil) database and included sex, age, APACHE II score, ventilation-days, length of stay, incidence of sepsis, tracheotomy, dialysis therapy and hemodynamic monitoring. For statistical analysis we used the chi-square test for evaluated difference of proportion, and considered statistical significance as P < 0.05. M El Toukhy, P McQuillan Portsmouth Hospital NHS Trust, Portsmouth, UK Critical Care 2007, 11(Suppl 2):P484 (doi: 10.1186/cc5644) Introduction We investigated patient management plans to ascertain the total number made, types of plan, priority, personnel responsible and expected time frame, proportion completed and the causes and consequences of failed plans (on the patient, the family and the critical care service). p p g Results There were 168 female (68.9%) and 75 male (30.7%) patients. P485 Outcome of very old patients on mechanical ventilation P486 Data on resource use of diagnostics, drugs, fluids, materials, admission and discharge were acquired from the computerized Patient Data Management System in both hospitals. Hotel and nutrition costs were collected from the respective financial departments. These costs were divided by the annual number of patient-days to calculate the cost per day. The NEMS or TISS scores in the academic or general hospital, respectively, were used to estimate nursing time per patient per day. The costs of medical specialists were based on the labour costs and the number of ICU days per year. In the academic hospital, time for consultations of medical staff attributable to each individual patient-day was prospectively collected using patient record forms. These costs we assumed to be comparable in the general hospital in the absence of detailed data. Outcome of octogenarians versus nonoctogenarians admitted to the intensive care unit with return of spontaneous circulation after out-of-hospital cardiac arrest I van Stijn, R Bosman, H Oudemans-van Straaten, P van der Voort, J Wester, D Zandstra, J van der Spoel OLVG, Amsterdam, The Netherlands Critical Care 2007, 11(Suppl 2):P486 (doi: 10.1186/cc5646) Outcome of octogenarians versus nonoctogenarians admitted to the intensive care unit with return of spontaneous circulation after out-of-hospital cardiac arrest I van Stijn, R Bosman, H Oudemans-van Straaten, P van der Voort, J Wester, D Zandstra, J van der Spoel OLVG, Amsterdam, The Netherlands Critical Care 2007, 11(Suppl 2):P486 (doi: 10.1186/cc5646) Introduction The aim of this study was to evaluate the outcome of octogenarians (O, age >79 years) versus nonoctogenarians (NO, age <80 years) in relation to predicted outcome (APACHE II predicted mortality, AIIPM) and length of stay in the ICU in days (LOS) after out-of-hospital cardiac arrest (OHCA). Methods From 1 January 1997 to 1 December 2006, the AIIPM, LOS and hospital mortality were prospectively recorded and the standardised mortality ratio (SMR) was calculated. Patients were categorised in cohorts of AIIPM. Unit costs of diagnostics and consumables were derived from the financial hospital databases. Labour costs were based on standardised costs per minute, which equalled the normative income divided by the number of workable minutes per year. Estimates of the costs of inpatient-days and nonpatient-related care were based on the annual account for 2005 of the hospitals. Nonpatient-related care (capital, overhead) was appointed to patients using a marginal mark-up percentage. Available online http://ccforum.com/supplements/11/S2 Available online http://ccforum.com/supplements/11/S2 Conclusion The percentage of older patients admitted to the ICU is increasing. The need for tracheotomy and dialysis as well as the length of stay are increasing with this population. APACHE scores do not seem to present a good relationship with mortality in this population. Dialysis and sepsis were associated with a significant increase in mortality. 200 consecutive patients admitted to a 32-bed mixed adult ICU at an academic hospital during two periods in 2006: 16 April–15 May and 5 June–23 June. For comparison, we collected detailed data at a general hospital that has a 10 bed-adult general ICU for the period 1 January–1 July 2003. The costs were adjusted to 2005 using the general price index. Both times, we applied a micro-costing approach, implying that all relevant resources were identified and valued at a detailed level. P486 Results Hospital mortality in the NO group was 58.9%, and in the O group was 75.4% (P = 0.001, chi-square). The LOS ICU was similar in both groups (Table 1; PM, predicted mortality). Conclusion In octogenarians admitted in the ICU after OHCA, hospital mortality is higher than in the younger group but still an important proportion survives. Non-octogenarians survived more often than predicted by APACHE II. Despite the higher mortality, ICU treatment after out of hospital resuscitation of octogenarians seems worthwhile. Results In the academic hospital the average total costs per ICU day amounted to €1,775, compared with €1,703 in the general hospital. The distribution of the costs by cost component varied. Results In the academic hospital the average total costs per ICU day amounted to €1,775, compared with €1,703 in the general hospital. The distribution of the costs by cost component varied. Conclusions The overall costs per day for IC in an academic hospital were slightly higher than the costs for an ICU day in a general hospital. These derived costs fit nicely to the official reference costs of €1,730 for an ICU day in The Netherlands, which is based on a global top-down approach. Conclusions The overall costs per day for IC in an academic hospital were slightly higher than the costs for an ICU day in a general hospital. These derived costs fit nicely to the official reference costs of €1,730 for an ICU day in The Netherlands, which is based on a global top-down approach. P488 L Hakkaart1, S Tan1, C Bouwmans1, M Al1, P Spronk2, J Bakker3 1Institute for Medical Technology Assessment, Rotterdam, The Netherlands; 2Gelre Hospital, Apeldoorn, The Netherlands; 3Erasmus MC, Rotterdam, The Netherlands Critical Care 2007, 11(Suppl 2):P487 (doi: 10.1186/cc5647) Does the Glasgow Coma Scale correctly diagnose the vegetative and minimally conscious states? Does the Glasgow Coma Scale correctly diagnose the vegetative and minimally conscious states? Causes and consequences of failure of implementation of management plans in critical care The mean age of the study population and the APACHE II score were 89.55 ± 3.61 years and 17.98 ± 6.3, respectively. Median ventilation-days and length of stay were 6 and 8.14 days, respectively. Tracheotomy was performed in 44.1%, dialysis therapy in 15.2% and hemodynamic monitoring in 19.8%. Only the group above 95 years old had a significant increase of days of ventilation and length of stay: 18.77 vs 10.47 days (P = 0.01) and 19.74 vs 12.86 days (P = 0.07), respectively. The predicted APACHE II mortality for the studied population was 26.9 ± 17.21% and the present rate to the population studied was 47.7%. Patients in dialysis and with diagnosis of sepsis at admission had poorer prognosis (respectively a 1.6 and 1.52 times likely ratio to die). Methods Over seven consecutive days, details of all consultant determined management plans were recorded by a dedicated nurse auditor. A plan was defined as an identifiable do-able, short- term action. Data on type, (arbitrary) priority, involved personnel and time frame were noted. The auditor later returned at the end of shift to determine whether plans had been completed in the appropriate time frame (successful plan) or not (unsuccessful plan). For unsuccessful plans, the nurse, senior nurse, senior house officer, fellow and consultant were all independently quizzed on causes and consequences (for patient, family, service) from a predetermined list of possibilities. Results Of 200 plans, 130 were successful, for three plans data were missing and 67 (34%) plans were unsuccessful. Of S192 Available online http://ccforum.com/supplements/11/S2 Does the Glasgow Coma Scale correctly diagnose the vegetative and minimally conscious states? C Schnakers1, J Giacino2, K Kalmar2, S Piret1, E Lopez2, M Boly1, R Malone2, S Laureys1 1University of Liege, Belgium; 2JFK Medical Center, Edison, NJ, USA Critical Care 2007, 11(Suppl 2):P488 (doi: 10.1186/cc5648) C Schnakers1, J Giacino2, K Kalmar2, S Piret1, E Lopez2, M Boly1, R Malone2, S Laureys1 1University of Liege, Belgium; 2JFK Medical Center, Edison, NJ, USA Critical Care 2007, 11(Suppl 2):P488 (doi: 10.1186/cc5648) Introduction For most countries, there are no good estimates for the costs of intensive care (IC) although it is known that the ICU is a major inpatient cost driver. The aim of this study was to estimate the real costs of IC in two hospitals in The Netherlands using a micro-costing methodology. al Care 2007, 11(Suppl 2):P488 (doi: 10.1186/cc5648) Introduction Progress in intensive care has led to an increase in the number of patients who survive severe brain injury and, therefore, the number of patients with impaired consciousness. Methods The costing study was undertaken at two hospitals in The Netherlands. We conducted a retrospective cost analysis of S Table 1 (abstract P486) NO O AIIPM n PM (SD) SMR LOS (days) n PM (SD) SMR LOS (days) 0–0.2 29 0.12 (0.07) 1.72 2.1 1 0.17 5.9 0 0.2–0.4 36 0.29 (0.05) 0.96 3.0 8 0.29 (0.07) 2.6 0.25 0.4–0.6 83 0.52 (0.06) 0.93 2.9 19 0.49 (0.06) 1.18 5.6 0.6–0.8 131 0.72 (0.06) 0.88 3.9 43 0.74 (0.06) 0.85 4.1 0.8–1.0 210 0.89 (0.05) 0.81 3.7 71 0.88 (0.05) 0.99 3.0 Total 489 0.69 (0.23) 0.85 3.5 (4.4) 142 0.75 (0.18) 1.0 3.4 (4.4) Table 1 (abstract P486) Intensive care of the elderly in Finland M Reinikainen1, A Uusaro2, M Niskanen3, E Ruokonen2 1North Karelia Central Hospital, Joensuu, Finland; 2University Hospital, Kupio, Finland; 3Helsinki University Central Hospital, Helsinki, Finland Critical Care 2007, 11(Suppl 2):P489 (doi: 10.1186/cc5649) Results From 1996 to 2005, 47.3% (4,717) of admissions to the ICU were aged ≥65 years; 24.0% (2,393) were ≥75 years. One- year survival of the young group (51.8%) was significantly (P < 0.001) better than the old group (37.9%). However, in those receiving ≥3 organ support (young n = 197; old n = 199), this significance is lost (42.2% vs 32.6%, P >0.2). Younger elective surgical patients had better survival than older (79.4%, n = 196 vs 64.5%, n = 173). There was no survival difference between young and old after emergency surgery (52.9%, n = 57 vs 50.4%, n = 85; P > 0.5). There was no difference between ‘young’ and ‘old’ groups in the EQ5D weighted health index (0.67 ± 0.30 vs 0.62 ± 0.29, P > 0.5) or performance status scores (1.73 ± 0.96 vs 1.72 ± 0.98, P > 0.5). The EQ5D scores of survivors were lower than matched population norms (0.64 vs 0.76, P < 0.01). Introduction The population is ageing. We wanted to find out how age affects resource consumption and outcome of intensive care in Finland. Introduction The population is ageing. We wanted to find out how age affects resource consumption and outcome of intensive care in Finland. Methods We analysed data on 79,361 admissions to 26 Finnish ICUs during the years 1998–2004. We measured the severity of illness with SAPS II scores and the intensity of care with TISS scores. Results The median age was 62 years; 8.9% of the patients were aged 80 years or older. The hospital mortality rate was 16.2% in the overall patient population but 28.4% for patients aged 80 years or older. In a multivariate logistic regression analysis, old age was an independent risk factor for hospital mortality (Table 1). Overall, the mean length of ICU stay was 3.1 ± 5.3 days; it was 3.2 ± 5.3 days in the age group 75–79 years but only 2.4 ± 3.5 days in the age group 80 years or older. Overall, the mean TISS score per day was 25.8 ± 10.9; it was 27.8 ± 10.7 in the age group 75–79 years and 25.3 ± 9.9 in the age group 80 years or older. One-year survival and functional outcome in critically ill elderly patients M Puntis, M Cecconi, R McGoldrick, H Robertshaw, G McAnulty St George’s Hospital, London, UK Critical Care 2007, 11(Suppl 2):P490 (doi: 10.1186/cc5650) Results Overall, 29 patients (16 acute and 13 chronic patients) were considered as being in a vegetative state based on the GCS. The FOUR identified four out of these 29 patients (1/16 acute and 3/13 chronic patients) as not being vegetative considering the presence of visual pursuit. The CRS-R identified an additional seven patients (4/16 acute and 3/13 chronic patients) showing visual fixation meeting the criteria for a minimally conscious state set forth by the Aspen Workgroup. Therefore, the GCS diagnosed a total of 38% (11/29) of conscious patients (5/16 acute and 6/13 chronic patients) as being in a vegetative state. Introduction The number of elderly ICU patients is increasing [1] but limited outcome data are available. In this pilot study we evaluated survival and quality-of-life indicators in ICU patients aged ≥65 years. Method Retrospective analysis of admissions between 1996 and 2005 defined the number of elderly ICU patients. Then between 2004 and 2006, consecutive patients ≥65 years admitted to general (631), cardiothoracic (722) or neurological (118) critical care units requiring ≥24 hours of ≥2 organ support were identified. Patients were divided into ‘young’ (age 65–74 years, n = 733) and ‘old’ (age ≥75 years, n = 738). Age, sex, organ support, diagnosis, and referral source were recorded. Patients were followed-up 1 year after discharge. A standard telephone interview of a random sample of survivors (young n = 15, old n = 22) assessed perfor- mance status and the EQ5D health-related quality of life [2]. Data were analysed using Kaplan–Meier and log rank. Conclusion Using the GCS can lead one to misdiagnose conscious patients. This misdiagnosis can lead to major clinical, therapeutic and ethical consequences. Using additional sensitive tools such as the CRS-R can avoid this kind of situation. Table 1 (abstract P486) Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Behavioral assessment remains the gold standard to monitor the level of consciousness. However, about one-third of patients diagnosed with a vegetative state are actually conscious (or in a minimally conscious state). We compared the ability of the famous Glasgow Coma Scale (GCS) and other standardized behavioral scales to correctly diagnose the vegetative state in an acute (intensive care and neurology ward) and chronic (neuro- rehabilitation) setting. in the age distribution of the Finnish population will increase the demand for ICU beds by 25% by 2030. Conclusions The hospital mortality rate increased with increasing age. The mean intensity of care and length of ICU stay were lower for the oldest patients than for patients <80 years old. The ageing of the population will probably cause a remarkable increase in the need for intensive care. P490 Methods Sixty postcomatose patients (that is, GCS > 8) were prospectively assessed using the GCS, the Full Outline of UnResponsiveness (FOUR) and the Coma Recovery Scale-Revised (CRS-R) in randomized order. The mean age was 50 years (range 18–86); 39 were men. Etiology was traumatic in 24 patients. One-year survival and functional outcome in critically ill elderly patients M Puntis, M Cecconi, R McGoldrick, H Robertshaw, G McAnulty St George’s Hospital, London, UK Critical Care 2007, 11(Suppl 2):P490 (doi: 10.1186/cc5650) One-year survival and functional outcome in critically ill elderly patients Intensive care of the elderly in Finland If the need for intensive care remains unchanged in each age group, the change Conclusion Survival is worse in older ICU patients, although initial data suggest no difference in functional outcome. Survivors have lower quality-of-life scores than population norms [3]. Further work is pending. References 1. Carson SS: Crit Care Clin 2003, 19:605-617. 2. Dolan P: Med Care 1997, 35:1095-1108. 3. Kind P: CHE Discussion Paper 172. York: Centre for Health Economics, University of York; 1999. References 1. Carson SS: Crit Care Clin 2003, 19:605-617. 2. Dolan P: Med Care 1997, 35:1095-1108. 3. Kind P: CHE Discussion Paper 172. York: Centre for Health Economics, University of York; 1999. References 1. Carson SS: Crit Care Clin 2003, 19:605-617. 2. Dolan P: Med Care 1997, 35:1095-1108. 3. Kind P: CHE Discussion Paper 172. York: Centre for Health Economics, University of York; 1999. 1. Carson SS: Crit Care Clin 2003, 19:605-617. 3. Kind P: CHE Discussion Paper 172. York: Centre for Health Economics, University of York; 1999. P493 Quality of life before intensive care unit admission is a strong predictor of survival Quality of life before intensive care unit admission is a strong predictor of survival P Spronk1, J Hofhuis1, H van Stel2, J Rommes1, A Schrijvers2, J Bakker3 1Gelre Ziekenhuizen Location Lukas, Apeldoorn, The Netherlands; 2Julius Institute, Utrecht, The Netherlands; 3Erasmus MC, Rotterdam, The Netherlands Critical Care 2007, 11(Suppl 2):P493 (doi: 10.1186/cc5653) Quality of life before intensive care unit admission is a strong predictor of survival P Spronk1, J Hofhuis1, H van Stel2, J Rommes1, A Schrijvers2, J Bakker3 1Gelre Ziekenhuizen Location Lukas, Apeldoorn, The Netherlands; 2Julius Institute, Utrecht, The Netherlands; 3Erasmus MC, Rotterdam, The Netherlands Critical Care 2007, 11(Suppl 2):P493 (doi: 10.1186/cc5653) P Spronk1, J Hofhuis1, H van Stel2, J Rommes1, A Schrijvers2, J Bakker3 Conclusion We have demonstrated that, for our unit, there was no statistically significant difference in hospital or ICU mortality between the two groups. In fact, the group with a haematological malignancy had a lower mortality than the control group. The presence of haematological malignancy, of itself, does not appear to increase the mortality risk, when compared with a population of patients without haematological malignancy of a similar age, APACHE II score and admission diagnosis. Objective To examine whether health-related quality of life (HRQOL) before admission to the ICU can be used as a predictor of mortality Available online http://ccforum.com/supplements/11/S2 existing disease and (ii) patients receiving ward-based rehabilitation with those who receive formalised rehabilitation in dedicated facilities. 34% and 75%. Historically, these patients have been regarded as having a poor prognosis once admitted to the ICU. We decided to compare the ICU and hospital mortality of these patients with patients of a similar age and severity of acute illness. Preliminary results Ten of the required 40 interviewees have so far been recruited. Preliminary analysis confirms that survivors experience a range of morbidity not well captured by professionally recommended measures, and that pre-existing disease is an important factor in both coping with new morbidity superimposed by critical illness, and in marshalling support. The process of rehabilitation appears to have important effects on perceptions of recovery, self-management strategies, and perceptions of HRQoL. Conclusions This qualitative enquiry has already provided, and will continue to provide, new and clinically relevant insights into patients’ experiences of morbidity, the processes of rehabilitation, recovery and perceived HRQoL following discharge into the community. Methods Twenty-four patients were admitted to the ICU from August 2004 to August 2006 with a haematological malignancy. These were case-matched using sex, age (±2 years), APACHE II score (±2) and admission diagnosis with patients admitted to the ICU without a diagnosis of haematological malignancy. Eighteen patients were matched to one case control; however, in six patients, two matches were found. Where it was impossible to differentiate between cases on the grounds of diagnosis, age or APACHE II score they were both included. We compared ICU and hospital mortality between the two groups. Results Patients with a haematological malignancy had an ICU mortality of 50%, and a hospital mortality of 58%. Control patients had an ICU mortality of 60%, and a hospital mortality of 67% (statistically nonsignificant). The length of time to admission between the two groups was significantly longer in the haematology group at 12.4 days, compared with 2.8 days in the control patients (P < 0.05). The level of organ support was the same between the two cohorts. P492 Design and methods A prospective cohort study in an university- affiliated teaching hospital. Patients admitted to the ICU for >48 hours were included. Close relatives completed the Short-form 36 (SF-36) within the first 48 hours of admission to assess the pre- morbid HRQOL of the patient. Mortality was evaluated from ICU admittance until 6 months after ICU discharge. Logistic regression and ROC analysis were used to assess the predictive value for mortality of the first general health question of the SF-36 (‘in general would you say the health of your relative is excellent, very good, good, fair or poor’), as well as HRQOL measured by the complete SF-36. The Acute Physiologic and Chronic Health Evaluation (APACHE) II score was used as an accepted mortality prediction model in ICU patients. Three models were constructed including the HRQOL (model A), APACHE II score (model B), or both (model C) to age and gender. Percentages of correct survival/death predictions were calculated. Quality of life following prolonged critical illness: insights from a qualitative approach P Ramsay Royal Infirmary of Edinburgh, UK Critical Care 2007, 11(Suppl 2):P492 (doi: 10.1186/cc5652) P491 94 Table 1 (abstract P489) Age group (years) Adjusted OR 95% CI 0–39 Reference 40–59 2.05 1.8–2.3 60–69 3.17 2.8–3.6 70–74 4.14 3.7–4.7 75–79 5.41 4.8–6.1 80– 7.08 6.3–8.0 The outcome of patients admitted to an intensive care unit with haematological malignancy: a case–control study P Hampshire, K Francis, S Davies, L Dagg Royal Liverpool University Hospital, Liverpool, UK Critical Care 2007, 11(Suppl 2):P491 (doi: 10.1186/cc5651) Introduction The outcome of patients with haematological malignancy admitted to the ICU has been reported as between S194 Available online http://ccforum.com/supplements/11/S2 P494 Methods ICU data were prospectively collected from March 2003 to November 2005. Oncologic patients were selected. QOL aspects were evaluated through the analysis of independence to accomplish daily living activities (IADL) after ICU discharge, defined as the patient’s ability to walk, eat by mouth, maintain an oriented conversation and bath himself. The number of organ failures was assessed through the SOFA score. Severe organ dysfunction (SOD) was defined if the patient had three or four points in any of the six domains of the SOFA score. According to the number of SOD, patients were divided into two groups: one with two or less SODs and another with three or more SODs. Groups were compared using Fisher’s exact test. Introduction We believe that by explaining and answering the questions of those relatives that wish it, we can alleviate the grief caused by the death of a relative in critical care. Death is a common outcome of critical illness and relatives are at high risk of problems with complicated or unresolved grief due to the sudden, often unexpected, manner of that death. We describe the establishment and results of a bereavement follow-up service. Introduction We believe that by explaining and answering the questions of those relatives that wish it, we can alleviate the grief caused by the death of a relative in critical care. Death is a common outcome of critical illness and relatives are at high risk of problems with complicated or unresolved grief due to the sudden, often unexpected, manner of that death. We describe the establishment and results of a bereavement follow-up service. Methods All relatives, since January 2001, have been offered bereavement follow-up. Following the death of a patient in critical care, relatives are informed of the bereavement follow-up service. After death, a booklet is given to the next of kin with information about the service. Four to six weeks later a condolence card is sent, which includes a reminder of the follow-up service. We do not offer a counseling service and details of other organizations providing this are given. Appointments are made by telephone. The interview usually takes place outside critical care and is led by a consultant and a specially trained nurse. Relatives are given the opportunity to ask questions. A monitoring form is completed. A letter is sent to the GP detailing the issues discussed. Results Seventy out of 793 patients had an oncologic diagnosis. P Ramsay Introduction The measurement of health-related quality of life (HRQoL) among survivors of critical illness has become a prominent feature of our outcomes research. Local research experience suggests that existing measures may fail to capture the broad spectrum of morbidity that survivors experience. The purpose of this research is to explore, through predominantly qualitative methods, critical-illness mediated morbidity among survivors of prolonged critical illness; a group in whom this type of morbidity appears to be most prevalent. An important secondary aim is to explore the contribution of the processes of rehabilitation and recovery to perceptions of HRQoL. Results Four hundred and fifty-one patients were included at admission to the ICU. At 6 months follow-up, 159 patients had died and 40 patients were lost to follow-up. When the general health item was used as an estimate of HRQOL, the area under the curve (AUC) for model A (0.719) was comparable with model B (0.721), and slightly better in model C (0.760). The percentage of wrong predictions was lower in model C (survival 27%; death 37%) compared with model A (30% and 41%). Similar results were found when using the complete SF-36. Methods Survivors who experienced prolonged critical illness (defined as ≥14 days mechanical ventilation) were identified from the Scottish Intensive Care Society Audit Group (SICSAG) database, Wardwatcher®. Participants were contacted ≤6 months following ICU discharge, and were invited to complete professionally recommended quality-of-life questionnaires (the Short Form 36 and EuroQol-5D) and to participate in a semi- structured interview. Interviews explored everyday experiences of ongoing morbidity and were analysed with regard to their corre- lation with the domains and scores of the HRQoL questionnaires. Purposive sampling provided clinically important insights into experiences and perceptions of health and pre-existing morbidity and, importantly, the processes of rehabilitation and recovery; that is, through comparison of (i) patients with/without appreciable pre- Conclusions This study shows that the pre-admission HRQOL measured with either the one-item general health question or the complete SF-36 are as good in predicting survival/mortality in ICU patients as the APACHE II score and improves prediction slightly when combined. As the one-item general health question is easily and quickly obtained, assessment of HRQOL before admission to the ICU may facilitate the decision process in determining which patients will benefit from ICU treatment. Intensive care unit utilization after esophagectomy R Iscimen1,2, D Brown2, F Whalen2, T Roy2, S Cassivi2, M Keegan2 1Uludag University Faculty of Medicine, Bursa, Turkey; 2Mayo Clinic College of Medicine, Rochester, MN, USA Critical Care 2007, 11(Suppl 2):P496 (doi: 10.1186/cc5656) Conclusions We describe the results of a bereavement follow-up service for families whose relatives died on the critical care unit at University Hospital of Wales, Cardiff. In total, 5.7% of families took up the service offered. These were usually the families of younger than average male patients, who died with a critical care stay of less than 1 week. We believe that by answering questions still troubling the families 2–4 months after death, we can assist them with their grief. We also believe that this follow-up service by providing further communication can resolve some difficult issues before they develop into formal complaints. Introduction At our institution, postesophagectomy patients are usually managed in a progressive care unit with ICU admission reserved for those of high acuity. We hypothesized that ICU admission after esophagectomy is predictable and associated with high mortality. Introduction At our institution, postesophagectomy patients are usually managed in a progressive care unit with ICU admission reserved for those of high acuity. We hypothesized that ICU admission after esophagectomy is predictable and associated with high mortality. Methods A retrospective analysis of all patients after esophagectomy between January 2000 and June 2004 at a tertiary referral center. Data regarding demographics, preoperative morbidities, perioperative complications, APACHE III predictions, mortality, and lengths of stay were collected. P494 The male:female ratio was 2.18:1.0, and the average age of death was 42.9 years. A length of stay before death of 1 week or less occurred in 59.6%. Forty-seven per cent of families were seen between 2 and 4 months after the death of their relative. The issues most commonly raised were specific questions about the patient (56.2%), review of information in the notes (34.8%), complaints (23.6%), clarifying misunderstandings (18%) and contacting other health professionals (21.3%). P494 The mean age was 52 ± 19 years, male gender 56%, medical admission 77%, hematological malignancies 47% and mean APACHE II score 20 ± 8. ICU mortality was 53% and inhospital mortality was 71%. Nine (13%) patients were discharged of the hospital with complete IADL. Mortality in the group admitted with three or more SODs was 100%, while in the other group it was 39% (P = 0.01, OR 2.5 95% CI 1.8–3.6). During the ICU stay, patients who developed three or more SODs had a higher ICU and inhospital mortality than the ones who did not (89 x 23%, P < 0.001, OR 7, 95% CI 1.8–26 and 100 x 53%, P < 0.001, OR 2, 95% CI 1.4–2.6) and a smaller proportion of IADL after ICU and hospital discharge (0 x 22%, P = 0.04, OR 1.7, 95% CI 1.3–2.2 and 0 x 47%, P < 0.001, OR 2, 95% CI 1.4–2.6). Methods All relatives, since January 2001, have been offered bereavement follow-up. Following the death of a patient in critical care, relatives are informed of the bereavement follow-up service. After death, a booklet is given to the next of kin with information about the service. Four to six weeks later a condolence card is sent, which includes a reminder of the follow-up service. We do not offer a counseling service and details of other organizations providing this are given. Appointments are made by telephone. The interview usually takes place outside critical care and is led by a consultant and a specially trained nurse. Relatives are given the opportunity to ask questions. A monitoring form is completed. A letter is sent to the GP detailing the issues discussed. Conclusion Mortality should not be the only aspect analyzed when considering an ICU admission for an oncologic patient. The QOL, including IADL, must be taken into account. A higher number of SODs during the entire ICU stay is associated with higher ICU and inhospital mortality. Beyond this association, a smaller number of SODs may be associated with higher probability of IADL. Results In the 30-bed critical care unit in a teaching hospital, during study period January 2001–November 2006, 8,964 admissions and 1,560 deaths (17.4% of patients) occurred (male:female ratio 1.27:1). The average age of deaths was 64.7 years. Eighty-nine families were seen in bereavement follow-up (5.7% of total deaths) and two families attended for a second visit. P Ramsay S195 Critical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin P494 Five years experience of critical care bereavement follow-up S Voisey, J Davies, J Parry-Jones, N Stallard University Hospital of Wales, Cardiff, UK Critical Care 2007, 11(Suppl 2):P494 (doi: 10.1186/cc5654) P494 Visiting policies in Italian intensive care units: a national survey Visiting policies in Italian intensive care units: a national survey Methods We audited 28 ICU ward rounds. It was noted whether the patient was sedated or not sedated, and whether they had their eyes open or closed. Negative comments were recorded, and defined as comments regarding a patient’s poor progress or prognosis made at the bedside during the ward round. We also noted whether the patient was informed that the ward round was in progress, whether they were informed of the plan for the day, and whether any reassurance was offered. The other members of the team were not aware of the audit. A Giannini1, S Leoncino1, G Miccinesi2 1Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Milan, Italy; 2Centro per lo Studio e la Prevenzione Oncologica, Florence, Italy Critical Care 2007, 11(Suppl 2):P497 (doi: 10.1186/cc5657) Introduction Today no published data are as yet available on visiting policies in Italy’s approximately 600 ICUs. We carried out a multicentre survey to evaluate visiting policies in Italian ICUs. Results Twenty-eight ward rounds were audited, a total of 328 patient reviews. The total number of patients with their eyes open was 171, while 157 had their eyes closed. An adverse comment was made during 8.2% of reviews within earshot of the patient. A negative comment was made on 27 episodes, 13 of these were when the patient was not sedated but had their eyes closed. Four episodes occurred when the patient was not sedated and had their eyes open, while 10 were sedated and had their eyes closed. Of the 171 patients with their eyes open, 74 (43%) were informed that we were the team doing the ward round, while 97 (57%) were not spoken to at the start of the review. Fifty-three (31%) were informed of our management plan for the day and 43 (25%) were offered reassurance. In total, 103/171 patients (60%) with their eyes open were spoken to during the ward round, and we did not speak to 68 (40%). Methods An email questionnaire was sent to all 303 ICUs (general and specialized) in the Italian collaborative Gruppo Italiano per la Valutazione degli Interventi in Terapia Intensiva, asking about their visiting policies. Results The response rate was 84.8% (257/303). The median daily visiting time was 60 minutes (10th percentile: 30 minutes; 90th percentile: 120 minutes); however, 2% of ICUs allowed no visiting whatsoever. P498 and 17.0 (11.3–33.9) days, respectively. Compared with NICUGP, patients in ICUGP were more likely to have developed post- operative arrhythmia (57.9% vs 12.9%, P < 0.001), were older, of higher ASA status, and more likely to have diabetes, coronary artery disease, hypertension, a higher cancer stage, and to have received more intraoperative blood products. Of 352 patients originally not sent to the ICU, 43 (12.2%) were subsequently admitted to the ICU. These patients had higher APACHE III scores and were more likely to have ‘aspiration’ documented, although their mortality was not higher than direct ICU admissions. Conclusions After esophagectomy, overall mortality is low, but many patients require ICU admission. Postoperative arrhythmias and aspiration pneumonitis are especially problematic. and 17.0 (11.3–33.9) days, respectively. Compared with NICUGP, patients in ICUGP were more likely to have developed post- operative arrhythmia (57.9% vs 12.9%, P < 0.001), were older, of higher ASA status, and more likely to have diabetes, coronary artery disease, hypertension, a higher cancer stage, and to have received more intraoperative blood products. Of 352 patients originally not sent to the ICU, 43 (12.2%) were subsequently admitted to the ICU. These patients had higher APACHE III scores and were more likely to have ‘aspiration’ documented, although their mortality was not higher than direct ICU admissions. P498 Communication with patients during ward rounds on the intensive care unit: a prospective, observational, semiblind study K Francis, D Langhor, J Walker, I Welters Royal Liverpool University Hospital, Liverpool, UK Critical Care 2007, 11(Suppl 2):P498 (doi: 10.1186/cc5658) Communication with patients during ward rounds on the intensive care unit: a prospective, observational, semiblind study K Francis, D Langhor, J Walker, I Welters Royal Liverpool University Hospital, Liverpool, UK Critical Care 2007, 11(Suppl 2):P498 (doi: 10.1186/cc5658) Introduction It is good medical practice to communicate with patients regarding their condition and proposed treatment. Com- munication is essential to allow them to express their concerns and exercise their own autonomy, in a situation where they otherwise may have little control. Poor communication may contribute to unnecessary anxiety or depression. The aim of this audit was to observe whether the doctors communicated with patients on ward rounds. Conclusions After esophagectomy, overall mortality is low, but many patients require ICU admission. Postoperative arrhythmias and aspiration pneumonitis are especially problematic. P495 Results Four hundred and thirty-two patients underwent esophagectomy during the study period: 123 (28.5%) were admitted to the ICU (ICUGP) and 309 (71.5%) were not (NICUGP). Overall mortality was 3.7% (16 of 432 patients). Fifteen of 123 in ICUGP died in hospital (12.2%) compared with one of 309 in NICUGP. For ICUGP, mean (±standard deviation) acute physiology and APACHE III scores were 41.8 (±16.6) and 54.5 (±18.1), respectively. Forty-seven percent of ICUGP had a new (versus pre-existing postoperative) infiltrate on chest X-ray, 21.8% had positive sputum/bronchial culture and 5% positive blood culture within 48 hours of ICU admission. A total 13.8% of ICUGP had ‘aspiration’ documented in physician notes. The median (IQR) ICU and hospital lengths of stay were 3.6 (1.7–9.9) Quality of life aspects in oncologic patients who survived an intensive care unit admission D Forte, O Ranzani, N Stape, F Gianinni, R Cordioli, D Lima, J Coelho, P Nassar, R Zigaib, E Azevedo, I Schimidtbauer, F Silva, B Cordeiro, A Toledo-Maciel, M Park University of São Paulo, Brazil Critical Care 2007, 11(Suppl 2):P495 (doi: 10.1186/cc5655) D Forte, O Ranzani, N Stape, F Gianinni, R Cordioli, D Lima, J Coelho, P Nassar, R Zigaib, E Azevedo, I Schimidtbauer, F Silva, B Cordeiro, A Toledo-Maciel, M Park University of São Paulo, Brazil Critical Care 2007, 11(Suppl 2):P495 (doi: 10.1186/cc5655) Introduction The number of organ failures in oncologic patients admitted to the ICU is a good predictor of mortality. We propose to analyze the association of this variable and quality of life (QOL) aspects in oncologic patients who survived an ICU admission. S196 Available online http://ccforum.com/supplements/11/S2 Visiting policies in Italian intensive care units: a national survey A total 54.8% of ICUs surveyed had only one daily visiting slot, and 44% two. Only 1.2% had more than two visiting slots. The number of visitors was restricted in 91.8% of ICUs. The type of visitors (immediate family only) was restricted in 17.5% of ICUs. Children were not permitted to visit in 69.1% of ICUs and 17.5% had a minimum age limit for visitors. In the case of a dying patient, 20.6% of ICUs did not alter the visiting policy; 49% extended visiting hours; 44% increased the number of slots; and 53% allowed more visitors. A gowning procedure was compulsory for visitors in 95.3% of ICUs. No waiting room was provided by 25.4% of ICUs. Conclusion On intensive care ward rounds, patients are often not engaged in conversations or allowed to express their concerns. The majority of patients were not offered reassurance or informed about the treatment plan. Improved communication skills may help to lessen patients’ anxiety and unnecessary stress both during their stay on ICU and following their discharge. Conclusions This is the first survey on visiting policies in Italian ICUs. Despite the widely-held conviction that there is no sound scientific basis for restricting visitors in ICUs [1-3], our findings show a clear tendency in Italian ICUs to apply restricted visiting policies (concerning visiting hours, number and type of visitors), which are only partially liberalized when the patient is dying. Our survey could contribute towards modifying current policies in favour of opening ICUs that are still ‘closed’ and promoting more appropriate and attentive care for the patient and his/her family. Hospital volume and outcome following mechanical ventilation on the intensive care unit S Gopal1, R O’Brien1, J Pooni1, S Macfarlane2 1The Royal Wolverhampton Hospitals NHS Trust, Wolverhampton, UK; 2ICNARC, Birmingham, UK Critical Care 2007, 11(Suppl 2):P499 (doi: 10.1186/cc5659) Acknowledgement We thank Gruppo Italiano per la Valutazione degli Interventi in Terapia Intensiva for their valuable help. Acknowledgement We thank Gruppo Italiano per la Valutazione degli Interventi in Terapia Intensiva for their valuable help. Introduction The study was undertaken to determine the relationship between hospital volume and mortality in mechanically ventilated adult medical and surgical patients. The regionalisation of adult critical care services has been suggested by healthcare providers and health policy-makers as a means of achieving the ideal balance of providing high-quality care that is both cost- effective and accessible. Recent studies have had conflicting results. 1. Burchardi H: Let’s open the door! Intensive Care Med 2002, 8:1371-1372. 1. Burchardi H: Let’s open the door! Intensive Care Med 2002, 8:1371-1372. 2. Berwick DM, et al.: Restricted visiting hours in ICUs: time to change. JAMA 2004, 292:736-737. 2. Berwick DM, et al.: Restricted visiting hours in ICUs: time to change. JAMA 2004, 292:736-737. 3. Slota M, et al.: Perspectives on family-centered, flexible visitation in the intensive care unit setting. Crit Care Med 2003, 31(Suppl):S362-S366. 3. Slota M, et al.: Perspectives on family-centered, flexible visitation in the intensive care unit setting. Crit Care Med 2003, 31(Suppl):S362-S366. S197 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin Figure 1 (abstract P500) Methods The Birmingham and Black Country Critical Care Network database was retrospectively reviewed over a 10-year period from 1 April 1996 to 31 March 2006. The database included 50,686 patient episodes. After exclusion (incomplete data 9,700 episodes, unventilated patients 19,244 episodes, mechanical ventilation for less than 24 hours 3,814 episodes, interhospital transfers 795 episodes) the final cohort included 9,920 adult medical patients and 7,210 surgical patients. Hospitals were grouped into five volume categories to aid inter- pretation of the results (<100; 100–149; 150–199; 200–249; ≥250 ventilation episodes/year). The odds ratio and 95% confi- dence intervals for death on the ICU were calculated in relation to the hospital volume of ventilation. Results For both medical and surgical patients there was no relationship between the hospital volume of ventilation and death on the ICU. The odds ratio remained insignificant even after adjustment for patient demographics, APACHE II score, length of ICU stay and urgency status. Hospital volume and outcome following mechanical ventilation on the intensive care unit Medical patients’ adjusted odds ratio was 0.735 (95% CI 0.604–0.894). Surgical patients’ adjusted odds ratio was 0.771 (95% CI 0.559–1.064). Conclusion There is no relationship between hospital volume and ICU mortality in both medical and surgical patients following mechanical ventilation. The results of this study do not support the argument for regionalisation of adult critical care services in the United Kingdom. 35.8 years (24–57); 133 men, 51 women. One hundred and five students are attending the course in order to improve their qualification, 87 are studying for the specialist title examination, 58 to work in the ICU and 47 to acquire new knowledge. They considered their main specialties to be: internal medicine (54), intensive care (15), surgery (10) and anesthesiology (seven). Sixty- five percent work in the ICU (12.7% are leaders, 19.5% daily routine, 86.4% on duty and 6.8% play all three functions), 6% have the specialist critical care title, 15.7% are associated with the Brazilian critical care society, 49.45% have medical residence in another area, 36.4% have other postgraduations. They self- considered around grade 6 for cognitive aspects, procedural skills and competence and near grade 8 for communication and relationship (see Figure 1). Cardiopulmonary resuscitation, mechanical ventilation, haemodynamics and neurointensivism are the most desirable subjects. P501 P501 Data completeness in the Finnish Intensive Care Quality Consortium database P Mussalo1, J Tenhunen2 1Intensium Ltd, Kuopio, Finland; 2Tampere University Hospital, Tampere, Finland Critical Care 2007, 11(Suppl 2):P501 (doi: 10.1186/cc5661) Continuous education in intensive care for physicians in Brazil: for whom and their needs R Goldwasser1, C David1, D Costa2, C Piras3, P Mello4, G Macedo5, A Barros6 1Hospital Universitario-Universidade Federal do Rio de Janeiro, Brazil; 2Hospital Universitario, Cuiaba, Brazil; 3SOESTI, Vitoria, Brazil; 4SOTIPI, Terezina, Brazil; 5SOTIERJ, Vassouras, Brazil; 6SOTIPE, Recife, Brazil Critical Care 2007, 11(Suppl 2):P500 (doi: 10.1186/cc5660) Introduction The postgraduation course had been developed by the Brazilian Critical Care Society (AMIB) to be applied to physicians from all regions of Brazil since 2004. The importance of this 360-hour course is to provide continuous education and to train abilities to make decisions and start treatment. Also, for those who are in ICU practice, to qualify for application of specialist examination. The main objective of this study is to identify who are the doctors that are looking for this course. Conclusions Doctors are mainly from the fourth decade, want to improve their qualification, and are usually working in ICUs. The low number of specialists who works in ICU is a reality and there is a need to expand it. The self-evaluation points to problems with knowledge and ability; however, communications and relationships were well adjusted. The diversity of data will assist the AMIB to provide continuous education and qualify doctors to attend the demand of intensivists in Brazil. g Methods An opinion poll was collected from the students on the first day of the class course approaching the following aspects: Methods An opinion poll was collected from the students on the first day of the class course approaching the following aspects: 1. Profile. P500 Continuous education in intensive care for physicians in Brazil: for whom and their needs Data completeness in the Finnish Intensive Care Quality Consortium database auses of all incidents (irrespective of patient outcome) Methods We assessed data completeness of a Finnish ICU quality benchmarking database from 1998 to March 2006 containing 93,964 admission records. The data completeness was defined as a ratio of available and required data at ICU admission level. We evaluated the dataset and selected 19 most significant admission scheme variables to be included in completeness ratio calculations. Results The majority of data (77.5%) was collected with the manual system and the remaining 22.5% with an integration software. The mean admission data completeness ratio (CR) increased from 85.3% at 1998 to 97.9% at 2005 (P = 0.01). Between the ICUs, the mean CR varied from 91.6% to 99.6% (P = 0.01). The mean CR of the data collected with the IVT was 98.7% and with the manual system was 95.1% (P = 0.01). The rate of 100% complete records per patient was 48.7% and it increased from 0.0% in 1998 to 71% in 2005. Results The majority of data (77.5%) was collected with the manual system and the remaining 22.5% with an integration software. The mean admission data completeness ratio (CR) increased from 85.3% at 1998 to 97.9% at 2005 (P = 0.01). Between the ICUs, the mean CR varied from 91.6% to 99.6% (P = 0.01). The mean CR of the data collected with the IVT was 98.7% and with the manual system was 95.1% (P = 0.01). The rate of 100% complete records per patient was 48.7% and it increased from 0.0% in 1998 to 71% in 2005. potential or actual harm was perceived in five (15%) of the incidents. Fifty-three per cent of events were reported by senior house officer grade and 47% of incidents were reported by a specialist registrar. Only one incident was reported by a nurse on the team. Conclusion Data completeness in the FICQC has improved during the study period, although there is still significant variation between ICUs. Improved data completeness and decreased proportion of missing data are most likely due to the increasingly common use of CIS and automated data collection. We conclude that measuring/reporting the amount of missing data is mandatory when data collection and data management procedures for benchmarking are being developed. Conclusions Interhospital transport of critically ill patients can pose important risks. In our study no actual patient harm occurred although most incidents had the potential to cause harm. P503 Maximisation of heart and lung donation in a neurosurgical intensive care unit Maximisation of heart and lung donation in a neurosurgical intensive care unit S Aerdts, J Hofstra Isala Klinieken, Zwolle, The Netherlands Critical Care 2007, 11(Suppl 2):P503 (doi: 10.1186/cc5663) S Aerdts, J Hofstra Isala Klinieken, Zwolle, The Netherlands Critical Care 2007, 11(Suppl 2):P503 (doi: 10.1186/cc5663) Introduction In this study we created a database to analyse the incidence and types of critical incidents that occurred during the interhospital transfer of critically ill patients. The transfer of critically ill patients presents important risks and the safety of patients has been shown to be facilitated by the development of standard equipment and specialist teams [1]. The West of Scotland Shock team is a designated regional transfer service based in Glasgow. We are involved in the interhospital transfer of patients and not primary retrieval. A recent study looking at critical incidents during the intrahospital transport of the critically ill highlighted the risks posed, and recommended the monitoring of incidents in order to aid the continuous improvement in patient safety [2]. No similar study has been carried out looking at the interhospital transport of the critically ill patient. Critical Care 2007, 11(Suppl 2):P503 (doi: 10.1186/c Introduction The number of heart-beating donors in The Netherlands is decreasing. This decrease is only partially compensated for by an increase of nonheart-beating donations, resulting in an increasing shortage of donor organs, especially of donor hearts and lungs. In 2005 compared with 2004 the number of patients waiting for a donor heart increased from 38 to 50 (32%). In lung donation the increase was 37% (from 79 to 108). One approach to reduce this shortage is to maximize the number of organs per donor by optimisation of donor treatment in the ICU. g g g We are involved in the interhospital transfer of patients and not primary retrieval. A recent study looking at critical incidents during the intrahospital transport of the critically ill highlighted the risks posed, and recommended the monitoring of incidents in order to aid the continuous improvement in patient safety [2]. No similar study has been carried out looking at the interhospital transport of the critically ill patient. Methods We investigated the possibilities for improvement of donor management in our ICU by a retrospective study in 37 heart- beating organ donors hospitalised in our ICU from 1993 to 2005. Data completeness in the Finnish Intensive Care Quality Consortium database 2. He/she is attending the course in order to: prepare for the specialist critical care examination (), improve qualification (), work at an ICU (), any other reason if they do not deal with critical care patients (). P Mussalo1, J Tenhunen2 1Intensium Ltd, Kuopio, Finland; 2Tampere University Hospital, Tampere, Finland Critical Care 2007, 11(Suppl 2):P501 (doi: 10.1186/cc5661) 3. If he/she works at an ICU: how long (years) and the role (duty, routine or leader). 4. Partners of AMIB (yes) (no); if they have specialist title recognized by the AMIB (yes) (no). Introduction Benchmarking has been an essential part of intensive care medicine in Finland since 1994. At present, web-based quality/performance reports are shared with the 24 members of the Finnish Intensive Care Quality Consortium (FICQC). Thirteen ICUs collect FICQC data manually and 11 ICUs utilize data collection software (IVT) integrated with the Clinical Information System (CIS). In recent literature, the completeness of data between centralized medical benchmarking registries varies widely [1,2]. We hypothesized that: (1) the completeness of data in FICQC has Introduction Benchmarking has been an essential part of intensive care medicine in Finland since 1994. At present, web-based quality/performance reports are shared with the 24 members of the Finnish Intensive Care Quality Consortium (FICQC). Thirteen ICUs collect FICQC data manually and 11 ICUs utilize data collection software (IVT) integrated with the Clinical Information System (CIS). In recent literature, the completeness of data between centralized medical benchmarking registries varies widely [1,2]. We hypothesized that: (1) the completeness of data in FICQC has 5. If he/she has other postgraduation or residency program. ( 6. Self-evaluation related to the critical patient knowledge (scales from 1 to 9, considering 9 the highest grade). 7. Interest in the subjects of intensive care medicine (scales from 1 to 9). Results From 2004 to 2005 the AMIB started eight postgraduation courses in different regions of Brazil; 250 students were enrolled; 184 had answered the survey. The average age was S198 Available online http://ccforum.com/supplements/11/S2 Table 1 (abstract P502) Causes of all incidents (irrespective of patient outcome) Communication problem 10 (29%) Organisational delay 7 (21%) Lack of staff 2 (6%) Equipment failure 9 (26%) Poor preparation of patient 5 (15%) Staff injury 1 (3%) increased over the years and (2) the variation between the different units still exists. P502 2. Beckmann U, Gillies D, Berenholtz S, et al.: Incidents relat- ing to the intra-hospital transfer of critically ill patients. Intensive Care Med 2004, 30:1579-1585. References References Analysis of critical incidents during the interhospital transport of critically ill patients Analysis of critical incidents during the interhospital transport of critically ill patients P Doherty, B Digby Western Infirmary, Glasgow, UK Critical Care 2007, 11(Suppl 2):P502 (doi: 10.1186/cc5662) References 1. Faculty of Intensive Care and Australasian College for Emer- gency Medicine: Minimum Standards for the Transport of the Critically Ill Patient; 2003 [http://www.acem.org.au/media/ policies_and_guidelines/min_standard_crit_ill.pdf] References 1. Arts D, et al.: Intensive Care Med 2002, 28:656-659. 2. Afessa B, et al.: Intensive Care Med 2005, 31:1537-1543. Data completeness in the Finnish Intensive Care Quality Consortium database The majority of incidents were caused by system-based factors. This database has allowed us to perform continuous service development and education of staff. P504 Medical practices during the last 48 hours of life in children admitted to seven Brazilian Pediatric intensive care units P Lago, J Piva, P Garcia PUCRS, Porto Alegre, Brazil Critical Care 2007, 11(Suppl 2):P504 (doi: 10.1186/cc5664) P Lago, J Piva, P Garcia PUCRS, Porto Alegre, Brazil Critical Care 2007, 11(Suppl 2):P504 (doi: 10.1186/cc5664) P Lago, J Piva, P Garcia PUCRS, Porto Alegre, Brazil Critical Care 2007, 11(Suppl 2):P504 (doi: 10.1186/cc5664) Results A total of 137 physicians and critical care nurses completed the survey. The average age was 34 years and 58% were males. ‘Brain death’ was defined as an ‘irreversible cessation of brainstem function’ by 85% of respondents; 77% relying on clinical examination, 49.6% consulting neurophysicians and 28.3% ordering further testing to confirm the diagnosis. Withdrawal of life support is practiced by 83.2%; most frequently in the setting of absent brainstem and cortical functioning (74.3%), followed by acute, progressive multiorgan failure (39.8%). Physicians are more likely (P value 0.000) to withdraw mechanical ventilation, compared with nurses who would withdraw vasopressors (P value 0.006). The primary physician is the most frequent caregiver (60.2%) to start a discussion on withdrawal of life support, with 72.6% respondents consulting the Hospital Ethics Committee. Only 13.3% respondents never withdraw life support; 28.3% considered it their responsibility to ‘sustain life at all costs’ and only 8% gave religious beliefs as a reason. Only 56.6% favored organ harvest for transplantation from cadavers, while 64.6% supported harvest from brain dead individuals. Nurses were significantly more likely to support organ harvest for transplant from heart-beating, brain dead individuals (P value 0.025) than cadavers (P value 0.000). Introduction During the last decades life support limitation (LSL) practices have been offered more frequently in Latin American pediatric intensive care units (PICUs). We hypothesize that, depending on the Brazilian region, the incidence of LSL and the medical management may differ. Objective To evaluate the incidence of LSL practices and the medical management during the last 48 hours of life of children admitted to seven PICUs located in regions of Brazil. Methods A multicenter, observational and retrospective chart review study. The medical chart of all deaths occurring between January 2003 and December 2004 in seven Brazilian PICUs located in Porto Alegre (two), Sao Paulo (two) and Salvador (three) were evaluated. End-of-life care in the critically ill: a description of knowledge, attitudes and practices of physicians and nurses from Karachi, Pakistan The primary physician is the most frequent caregiver (60.2%) to start a discussion on withdrawal of life support, with 72.6% respondents consulting the Hospital Ethics Committee. Only 13.3% respondents never withdraw life support; 28.3% considered it their responsibility to ‘sustain life at all costs’ and only 8% gave religious beliefs as a reason. Only 56.6% favored organ harvest for transplantation from cadavers, while 64.6% supported harvest from brain dead individuals. Nurses were significantly more likely to support organ harvest for transplant from heart-beating, brain dead individuals (P value 0.025) than cadavers (P value 0.000). Methods We carried out a cross-sectional survey of clinicians working at three hospitals in Karachi (one private, university hospital, one mixed public and private, tertiary care hospital and one large government-funded hospital). A 13-question instrument was developed to assess recognition of end-of-life in the ICU, knowledge of commonly used terms to describe limitations of care, and attitudes and practices towards withdrawal and limitation of life-support measures and organ harvest for transplantation. After measuring the frequencies for presentation of the data, differences between the three respondent subgroups were compared using a chi-square analysis. Fisher’s exact test was used where the individual cell count was <5. A one-way analysis of variance was used to compare differences in age and years of practice. A two- sided P value of <0.05 was considered statistically significant. P503 There was no protocol for the treatment of organ donors in our institution. Methods The study was a cross-sectional analysis of critical incidents occurring during interhospital transport that were reported to the West of Scotland Shock Team critical incident database set up in September 2005. The information obtained was categorised into: (a) where the incident took place, (b) type of incident, (c) written description of events, (d) outcome (potential or actual harm to the patient) and (e) designation of the staff member reporting the incident. Results The heart was donated in 18 of 37 patients (49%). Lung donation was possible in only eight of 37 donors (22%). Most hearts and lungs were rejected for transplantation for valid reasons. In some patients there was room for improvement: in two of the three cases where hemodynamic instability impeded heart and lung donation (one dying from subarachnoidal bleeding and one from ischemic cerebral infarction), hemodynamic instability was closely associated with the moment of cerebral death. In three further patients heart donation was not carried out because of wall movement abnormality or electrocardiogram abnormalities. None of Results A total of 199 transfers were performed over the 6-month period. Thirty-four critical incidents were reported. Twenty-four (70%) incidents took place before, seven (21%) during and three (9%) after transfer. No patients sustained actual harm, 29 (85%) were perceived by the reporter to have suffered potential harm and the most common cause of this were delays in the transfer. No S199 ritical Care March 2007 Vol 11 Suppl 2 27th International Symposium on Intensive Care and Emergency Medicin End-of-life care in the critically ill: a description of knowledge, attitudes and practices of physicians and nurses from Karachi, Pakistan End-of-life care in the critically ill: a description of knowledge, attitudes and practices of physicians and nurses from Karachi, Pakistan N Salahuddin, A Ahmed, S Shafquat Aga Khan University & Hospital, Karachi, Pakistan Critical Care 2007, 11(Suppl 2):P505 (doi: 10.1186/cc5665) Introduction As the numbers of people admitted to ICUs are increasing, physicians are faced with obligations beyond attempting to reverse illness and include providing quality end-of- life care. Barriers to this include inadequate understanding of the dying patient and withdrawal or limitation of care. The objectives of this study were to document the comprehensions of physicians and nurses dealing with these situations. Conclusion On the basis of this retrospective study we conclude that donor management in our ICU can be improved. A management protocol with special attention for treatment of disturbance in cardiac and pulmonary function caused by sympathic overstimulation might considerably increase the amount of hearts and lungs donated, contributing to a decrease in organ shortage. and nurses dealing with these situations. Methods We carried out a cross-sectional survey of clinicians working at three hospitals in Karachi (one private, university hospital, one mixed public and private, tertiary care hospital and one large government-funded hospital). A 13-question instrument was developed to assess recognition of end-of-life in the ICU, knowledge of commonly used terms to describe limitations of care, and attitudes and practices towards withdrawal and limitation of life-support measures and organ harvest for transplantation. After measuring the frequencies for presentation of the data, differences between the three respondent subgroups were compared using a chi-square analysis. Fisher’s exact test was used where the individual cell count was <5. A one-way analysis of variance was used to compare differences in age and years of practice. A two- sided P value of <0.05 was considered statistically significant. Results A total of 137 physicians and critical care nurses completed the survey. The average age was 34 years and 58% were males. ‘Brain death’ was defined as an ‘irreversible cessation of brainstem function’ by 85% of respondents; 77% relying on clinical examination, 49.6% consulting neurophysicians and 28.3% ordering further testing to confirm the diagnosis. Withdrawal of life support is practiced by 83.2%; most frequently in the setting of absent brainstem and cortical functioning (74.3%), followed by acute, progressive multiorgan failure (39.8%). Physicians are more likely (P value 0.000) to withdraw mechanical ventilation, compared with nurses who would withdraw vasopressors (P value 0.006). P505 them had previous cardiac disease. All three had disturbances in cardiac rhythm closely related to the occurrence of cerebral death. Two of these three patients also developed neurogenic pulmonary edema. We speculate that in all five patients the instability leading to the decision not to perform heart and lung donation was caused by excessive sympathic stimulation at the time of cerebral death leading to impaired myocardial function and neurogenic pulmonary edema. These disturbances may be reversible within a few hours. Inotropic therapy, judicious fluid administration guided by close hemodynamic monitoring together with a trial of treatment with triple hormonal therapy (corticosteroid, vasopressin and thyroid hormone) might have improved cardiac and pulmonary function, rendering heart and lung donation possible. P505 End-of-life care in the critically ill: a description of knowledge, attitudes and practices of physicians and nurses from Karachi, Pakistan N Salahuddin, A Ahmed, S Shafquat Aga Khan University & Hospital, Karachi, Pakistan Critical Care 2007, 11(Suppl 2):P505 (doi: 10.1186/cc5665) P506 Methods We identified original research articles on critical care in three high impact factor journals (N Engl J Med, JAMA and The Lancet) published from 2001 to 2005. A list of the countries where data collection occurred was extracted. Eight countries contributed to ≥10 studies. A collaborator in each country was asked to provide baseline critical care information for their country from 2005, or as close to that date as possible. World Resources in Critical Care Study: a survey of critical care research and resources in eight countries H Wunsch1, D Harrison2, O Collange3, N de Keizer4, R Fowler5, E Hoste6, A Kersten7, W Linde-Zwirble8, A Sandiumenge9, D Angus8, K Rowan2 1Columbia University, New York, USA; 2ICNARC, London, UK; 3Strasbourg University Hospital, Strasbourg, France; 4University of Amsterdam, The Netherlands; 5Sunnybrook Health Sciences Center, Toronto, Canada; 6Ghent University Hospital, Ghent, Belgium; 7University Hospital Aachen, Germany; 8University of Pittsburgh, Pittsburgh, PA, USA; 9University Hospital Joan XXIII, Tarragona, Spain Critical Care 2007, 11(Suppl 2):P506 (doi: 10.1186/cc5666) H Wunsch1, D Harrison2, O Collange3, N de Keizer4, R Fowler5, E Hoste6, A Kersten7, W Linde-Zwirble8, A Sandiumenge9, D Angus8, K Rowan2 Results Sixty-two studies involving data from 51 countries were identified. Eight countries contributed data to ≥10 studies during this time period: the USA (26 studies), France (18), the United Kingdom (14), Canada (13), Belgium (12), Germany (10), The Netherlands (10) and Spain (10). Relevant data on baseline hospital and critical care resources for the eight countries identified are presented in Figure 1 (data from Canada not available). Adult ICU beds ranged from 3.3/100,000 population in the United Kingdom to 24.6 in Germany, and represented a range of 1.4% of all acute care hospital beds in the United Kingdom to 11.0% of all beds in the USA. 1Columbia University, New York, USA; 2ICNARC, London, UK; 3Strasbourg University Hospital, Strasbourg, France; 4University of Amsterdam, The Netherlands; 5Sunnybrook Health Sciences Center, Toronto, Canada; 6Ghent University Hospital, Ghent, Belgium; 7University Hospital Aachen, Germany; 8University of Pittsburgh, Pittsburgh, PA, USA; 9University Hospital Joan XXIII, Tarragona, Spain Critical Care 2007, 11(Suppl 2):P506 (doi: 10.1186/cc5666) Introduction Critical care research involves data from many countries, but critical care resources in these countries are unknown. We hypothesized that there are large differences in critical care resources between countries. Conclusions Many countries contribute substantially to critical care research. However, the underlying critical care resources vary dramatically among these countries. P504 Two pediatric intensive care residents of each service filled a standard protocol searching for: demographic data, mode of death (full reanimation, nonreanimation orders or withdrawn treatment) and medical management during the last 48 hours of life. Student’s t test, analysis of variance, chi-square test and relative risk were used for comparing the data. Results There were 561 deaths, 36 being excluded that died with less than 24 hours, 61 with brain death and 36 missing charts. Full cardiopulmonary reanimation was offered to 56.5%, with differences between the northeast and southeast regions (P < 0.001). Higher age (P = 0.02) and long length of PICU stay were associated with nonreanimation orders. The plan for LSL was recorded in a clear manner in just 52.7%. No respiratory support was observed in 14 dying children. For 66% patients with do-not- resuscitate orders the inotrope drugs were maintained or increased in the last 48 hours. Conclusion There are deficiencies and disparities in the understandings of physicians and nurses on the recognition and management of end-of-life in the ICU. Conclusions The incidence of LSV has increased among the Brazilian PICUs with a difference between the regions. The nonreanimation order is still the most common practice with scarce initiative for withdrawn life support. S200 P506 Figure 1 (abstract P506) Baseline critical care resources in eight countries. *Extrapolated from survey data, not full national data. Figure 1 (abstract P506) S201
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DRIVERS OF SUSTAINABILITY OF AGRICULTURAL COOPERATIVES IN KENYA: A CASE OF MACHAKOS COUNTY
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IVERS OF SUSTAINABILITY OF AGRICULTURAL COOPERATIVES IN KENYA: A CASE OF MACHAKOS COUNT IVERS OF SUSTAINABILITY OF AGRICULTURAL COOPERATIVES IN KENYA: A CASE OF MACHAKOS COUNT DRIVERS OF SUSTAINABILITY OF AGRICULTURAL COOPERATIVES IN KENYA: A CASE OF MACHAKOS COUNTY DRIVERS OF SUSTAINABILITY OF AGRICULTURAL COOPERATIVES IN KENYA: A CASE OF MACHAKOS COUNTY 1* Elizabeth Muange Kasungwa, 2* Dr. Makori Moronge 1* Student, Jomo Kenyatta University of Agriculture & Technology (JKUAT), Kenya 2* Lecturer, Jomo Kenyatta University of Agriculture & Technology (JKUAT), Kenya Accepted May 3, 2016 1* Student, Jomo Kenyatta University of Agriculture & Technology (JKUAT), Kenya 2* Lecturer, Jomo Kenyatta University of Agriculture & Technology (JKUAT), Kenya Key Words: Sustainability, Agricultural Cooperatives, Managerial skills, Stakeholder Participation, Access to Finance, Competitive Environment ELIZABETH MUANGE KASUNGWA, DR. MAKORI MORONGE Vol. 3, Iss. 2 (13), pp 271-295, May 3, 2016, www.strategicjournals.com, ©strategic Journals ABSTRACT Kenya has a long history of cooperative development and is recognized by the government to be a major contributor to national development, as they are found in almost all sectors of the economy. The Kenya’s population participates directly or indirectly in cooperative-based enterprises. According to the government of Kenya, it is estimated that 80 per cent of Kenya’s population derives their income either directly or indirectly through cooperative activities. Although significant progress has been made in the establishment of agricultural cooperatives, sustainability is a major challenge for majority of these cooperatives. The performance and sustainability of these cooperatives in Kenya, have been debatable, since the number of cooperatives becoming dormant (have actually closed down) is increasing over time. This study sought to establish the determinants of sustainability of agricultural cooperatives in Kenya. The specific objectives of the study were to examine how managerial skills, access to finance, stakeholder involvement and competitive environment affect sustainability of agricultural cooperatives in Kenya. The study adopted a descriptive design and the target population was 750 staff (senior and middle level management) of agricultural cooperatives drawn from different sub-counties in Machakos County. The sample size for the study was 80 respondents. A stratified sampling technique was carried out by involving all the targeted respondents and primary data was collected through the use of questionnaires. The secondary data was obtained from published documents such as journals, periodicals, magazines and reports to supplement the primary data. A pilot study was conducted for the data collection instrument. The data was with help of SPSS version 21 and Excel. The study adopted a correlation and regression analysis at 5% level of significance to determine strength and direction of the relationship of the variables under study. The regression analysis showed that managerial skills had the strongest positive (Pearson correlation coefficient =.875) influence on sustainability of agricultural cooperatives. In addition, access to finance, competitive environment and stakeholder involvement were positively correlated to sustainability of agricultural cooperatives with Pearson correlation coefficient of .581, .690 and .806 with p-values of .009<0.05, .008<0.05 and .006<0.05 respectively. The study established that managerial skills were the most significant factor. The study recommends for similar studies to be undertaken in other agricultural organizations in Kenya for generalization of the findings of this study. Background of the Study The formal definition of a co-operative is ‘an autonomous association of persons united voluntarily to meet their common economic, social, and cultural needs and aspirations through a jointly owned and democratically-controlled enterprise’. The ILO (2010, 2014) and UN (2009), among other organizations, have recognized that co-operatives in developing countries can play an important role in reducing poverty and improving wellbeing. The ILO and the International Co-operative Alliance (ICA), which federates nearly one billion cooperative members worldwide, have also outlined how co- operatives can contribute to the SDGs (ILO and ICA, 2014). With their particular values (self-help; self- responsibility; democracy; equality; equity; solidarity) and principles and mode of governance (voluntary and open membership; democratic member control; member economic participation; autonomy and independence; education, training and information; co-operation among cooperatives; concern for the community), co-operatives have been seen as having considerable potential for promoting economically and socially inclusive development. ABSTRACT - 272 - government interference and failure (Develtere, Pollet, &Wanyama, 2008) and yet, in more recent times, have been able to grow in numbers while serving the poor communities in the region. It has been argued that the advent of liberalisation in the 1990s in the African context has enabled agricultural co-operatives to develop as genuine member-controlled and business-oriented organisations which in turn have improved the wellbeing of vulnerable people (Wanyama, 2013). However, agricultural co-operatives in the African continent have shown a mixed-picture in terms of performance and sustainability (Francesconi& Ruben, 2008; Francesconi&Wouterse, 2011). While there are success stories, not all agricultural co- operative endeavours have been sustainable but those that have can provide key insights for co- operative resilience Cooperatives The first agricultural cooperatives were created in Europe in the seventeenth century in the Military Frontier, where the wives and children of the border guards lived together in organized agricultural cooperatives next to a funfair and a public bath. The first civil agricultural cooperatives were created also in Europe in the second half of the nineteenth century. They spread later to North America and the other continents. They have become one of the tools of agricultural development in emerging countries. Farmers also cooperated to form mutual farm insurance societies. Also related are rural credit unions. They were created in the same periods, with the initial purpose of offering farm loans. Some became universal banks such as CréditAgricole or Rabobank. (Birchall, 2004) In recent decades agricultural co-operatives have been rediscovered as organizations with the potential to foster socio-economic development and to reduce poverty (Bibby& Shaw, 2005; Birchall, 2003, 2004; FAO, 2012; Mu¨nkner, 2012; UN, 2011; Vicari& De Muro, 2012). In the current economic and financial climate there is a renaissance of co- operatives, national and international organisations are concerned with understanding the extent to which cooperatives in developing countries have been able to cope with economic and political crises. Local Perspective of Sustainability of Agricultural Cooperatives There is special interest in Africa where these organisations endured decades of mismanagement, Kenya has a long history of cooperative development that has been characterized by strong growth, thus making a significant contribution to the overall economy. (Ministry of cooperative development & marketing, 2008) Cooperatives are recognized by the government to be a major contributor to national development, as cooperatives are found in almost all sectors of the economy. With the total population of Kenya at approximately 37.2 million (Republic of Kenya, 2008a: 13), it is estimated that 63 per cent of Kenya’s population participate directly or indirectly in cooperative-based enterprises (GoK, 2008). debatable, since the number of cooperatives becoming dormant (have actually closed down) is increasing over time (GoK, 2013). In addition, a survey conducted by the Ministry of Cooperative Development and Marketing reported that from a sample of 220 cooperatives only 3.63% were considered to be sustainable, 35% cooperatives had an average sustainability score and 78% were considered not sustainable. Cooperatives The cooperatives scores were based on 3 sets of criteria; the existence of a business plan (50%), the degree of representation (20%) and management (30%) (GoK, 2012).The poor sustainability of agricultural cooperatives in Kenya has been attributed to poor leadership, lack of managerial skills, stakeholder involvement and competitive environment (RoK, 2012; WOCCU, 2010). Munkner, 2015; Birchall, 2011; Mazzrol et al., 2011).It is on this premise that this study seeks to establish the drivers of sustainability of agricultural cooperatives in Kenya specifically Machakos county. Could managerial skills, stakeholder involvement, access to finance and competitive environment be drivers of sustainability of agricultural cooperatives in Kenya? This study sought to explore more. The movement is supposed to play an important role in wealth creation, food security and employment generation and hence participate in poverty alleviation. To date, there are over 11,200 registered cooperative societies country-wide. The membership is over 6.1million and has mobilized domestic savings estimated at over Kshs. 125 billion. The cooperatives have employed over 300,000 people, besides providing opportunities for self-employment. Indeed, a significant number of Kenyans, approximately 63% draw their livelihood either directly or indirectly from cooperative-based enterprises (Republic of Kenya 2007; International Monetary Fund 2007; The Kenya High Commission in the United Kingdom 2007). Statement of the Problem Cooperatives in Kenya contribute about 47% of the GDP and 34% of the national savings; empirical evidence indicates further that some 78% of the Kenyan people derive their livelihood either directly or indirectly from Cooperatives. During the year 2011, cooperatives recorded a turnover of about Ksh.50 Billion (WOCCU, 2010). From this data, we conclude that cooperatives have great potential as poverty economic pillars. The sustainability of these agricultural cooperatives in Kenya, have been General objective The main purpose of the study was to establish the determinants of sustainability of agricultural cooperatives in Kenya. LITERATURE REVIEW This chapter reviews relevant literature on determinants of sustainability of agricultural cooperatives in Kenya. Theoretical Framework This theory was proposed by Aaron Sapiro and E.G Nourse in the 1930s. Strength of the Sapiro and Nourse ideas is in specifying objectives and organizational structures for cooperatives that address the concerns of agricultural producers in a context of achieving a public interest role. In both schools of thought, cooperatives provide some balancing of market power, whether affecting the terms of trade for an industry-wide commodity, the Sapiro School, or in stimulating competition in specific markets, the Nourse School. In their conceptions, cooperatives capture a larger share of industry earnings for the membership, but additionally, contribute to market or industry efficiency. In other words, their philosophies of cooperation were grounded in a public interest perspective, as legislatively recognized in the Capper-Volstead Act of 1922. This section examines relevant theories to the study variables. According to Kombo and Tromp (2009), a theoretical framework is a collection of interrelated ideas based on theories. Specific objectives. The specific objectives of the study were to The specific objectives of the study were to i. Find out how managerial skills influence sustainability of agricultural cooperatives in Kenya. ii. Determine how stakeholder involvements affect sustainability of agricultural cooperatives in Kenya. - 274 - iii. Examine how access to finance influence sustainability of agricultural cooperatives in Kenya. philosophy. (Chaves and Sajardo, 2004) This theory supports the notion of an enabling environment and proper leadership that will foster sustainability in the long run. If people are motivated and given the impetus to apply themselves through creation of fair policies and equitable environment, then even their attitude to work will change and a new era of flourishing social and economic movements will be witnessed. The theory supports the managerial skills on sustainability of agricultural cooperatives. iv. Establish how competitive environment affect sustainability of agricultural cooperatives in Kenya. Theory of the co-operative movement It was proposed by Robert Owen in 1817. Robert Owen has been called the 'father of English Socialism'. He was the founder of the Co-operative movement and believed in worker control although he was a high capitalist himself. He was the product of self-help and a very practical man who concentrated on the 'means to the end'. The theory proposed that if the working man ever was to achieve equality, then the man must change first - in attitude. Also, the working man had to know of, believe in and be equipped to fight for the cause. This is very much the self-help ethic. (Chambers and Conway, 2006) Sapiro and Nourse made major contributions to the practical problems of achieving member commitment and cohesive organizations. Yet, subsequent cooperative thought moved further into examining and modeling key facets of internal organization, developing a more coherent theory of agricultural cooperation. Over the years since Sapiro and Nourse, there has been some shift in emphasis from concern with the external effects of Owen became convinced that the advancement of humankind could be furthered by the improvement of every individual's personal environment. He reasoned that since character was molded by circumstances, then improved circumstances would lead to goodness. The environment at New Lanark, where he tried out his ideas, reflected this - 275 - the way they respond to their members needs using the capital at their disposal. The resource-based view is grounded in the perspective that a firm's internal environment, in terms of its resources and capabilities, is more critical to the determination of strategic action than is the external environment. "Instead of focusing on the accumulation of resources necessary to implement the strategy dictated by conditions and constraints in the external environment, the resource-based view suggests that a firm's unique resources and capabilities provide the basis for a strategy. The business strategy chosen should allow firms to best exploit its core competencies relative to opportunities in the external environment" (Barney, 2002).The theory supports the competitive environment on sustainability of agricultural cooperatives. organization to the internal or micro aspects of organizing and sustaining cooperation (Chaves and Sajardo, 2004). This theory espouses sound leadership in the cooperative movement and connects proper leadership and sound governance to a satisfied cooperative membership, proper financial management and a thriving cooperative movement. The theory supports the access to finance and managerial skills on sustainability of agricultural cooperatives. Cooperatives Dynamic Theory According to Nzuve (2009), cooperative and mutual organizational forms arise for reasons that include contracting problems between parties. Economic literature suggests a variety of allocative inefficiencies implied by these forms that largely have their origins in poor investment decisions. It is demonstrated that a multi-period model and the supplier and cooperative valuations it implies the essentials for understanding the sources of inefficiency and solutions to them. Using the case of supplier co-operative shows that economic inefficiency arises because of the common over- supply of input induced by suppliers responding to average, rather than marginal, revenue, and that investment is actually efficient given the supply of input. The presence of unknown capital is an important source of over-supply. We show that if the cooperative's shares are priced at the present value of expected dividends and supplier entry and exit decisions are taken solely on the basis of profitability of membership then there is no inefficiency and we describe a functioning example. Finally, our valuations show that that there is no "time horizon" investment problem, at least from an industry perspective (Chandler, 1962). Conceptual Framework Mugenda, (2008) defines conceptual framework as a concise description of the phenomenon under study accompanied by a graphical or visual depiction of the major variables of the study. Kombo and Tromp, (2009) defines it as a set of broad ideas and principles taken from relevant fields of inquiry and used to structure a subsequent presentation. It is a research tool intended to assist a researcher to develop awareness and understanding of the situation under scrutiny and to communicate this. Bell, (2010) describes it as a diagrammatical representation that shows the relationship between dependent and independent variables. A conceptual framework assists a researcher to organize their thinking and complete an investigation successfully. It also explains the relationship among interlinked concepts and explains the possible connection between the variables (Kombo & Tromp, 2009).The conceptual framework comprises of the independent variables also known as the exploratory variables and which are the presumed cause of changes in the dependent variable and the dependent variable also called the criterion or predictor variable which the researcher wishes to explain (Kothari, 2004). The following framework depicts the relationship between the independent and dependent variables based on four independent variables and a dependent variable as represented diagrammatically in figure 2.1. In this study, sustainability of agricultural cooperatives is dependent on managerial skills, member participation, access to finance and government policy. Co-operative Commonwealth Theory Co-operative Commonwealth Theory In some Co-operative economics literature, the aim is the achievement of a Co-operative Commonwealth; a society based on cooperative and socialist principles. Co-operative economists - Federalist, Individualist, and otherwise - have presented the extension of their economic model to its natural limits as a goal. This ideal was widely supported in early-twentieth century U.S. and Canadian leftist circles. This ideal, and the language behind it, were central to the formation of the Co- operative Commonwealth Federation in 1935, which became Canada's largest left-wing political party, and continues to this day as the New Democratic Party. They were also important to the economic principles of the Farmer-Labor Party of the United States, particularly in the FLP's Minnesota affiliate, where advocacy for a Co- operative Commonwealth formed the central theme of the Party's platform from 1934, until the Minnesota FLP merged with the state Democratic Party to form the Democratic–Farmer–Labor Party in 1944 (Eias, 2010) Saccos in Kenya have proved to be dynamic in the way they are formed Saccos exist in all spheres of society from the urban salaried workers Saccos to the rural farmers Saccos. All these are dynamic in - 276 - In Kenya co-operatives have been formed as social organizations that are formed by people with a common goal of uplifting their financial well-being .In Kenya many co-operative societies have had their influence in Kenya’s political scene as co- operatives specifically cooperatives control a large chunk of the National savings as well as over 15 million Kenyans who are members. Some giant cooperatives mainly in Kenya have seen some of their officials be elected as members of parliament and have gone ahead to hold senior positions in Government .a case in point is the former minister of Co-operatives Mr Njeru Ndwiga who was a former chairman of Parliament cooperatives have also grown to become a sector of the economy to an extent where the Government has formed the Ministry of Co-operative development to specifically formulate policies to regulate and supervise them. and management of cooperatives as well as influence of other services offered by cooperatives. The theory supports the managerial skills on sustainability of agricultural cooperatives. Scientific Theory of Management Frederick Winslow Taylor developed the scientific theory of management which he published in the journal of the American Society of Mechanical Engineers in 1895. Scientific Management focuseson the efficient accomplishment of work tasks with an attitude of work smarter, not harder. Taylor meant his methods to be both a win for management in increasing productivity and a win for laborers making their jobs easier. But Taylor as a mechanical engineer focused on the physical aspects of the job and the formal organization of the shop. Scientific management was the seed bed of the Efficiency Movement in the United States. His consideration of motivation was primarily limited to the scientific determination of fair financial incentives for worker performance (Wren, 2005). This study focuses on drivers that influence sustainability of agricultural Cooperatives. Such factors include management skills that are geared to improve productivity of cooperatives, marketing - 277 - Independent variable Dependent variable Figure 1 Conceptual Framework Managerial skills  Technical  Conceptual  Human Competitive Environment  Product Differentiation  Disadvantage Edge  Fair Play Access to Finance  Credit facility  Collateral  Cost of funds Stakeholder Participation  Commitment  Patronage  Loyalty Sustainability of Agricultural Cooperatives  Years of operation  Number of branches opened  Increase of profits private business organization that is jointly owned and controlled by its members (IRG, 2005). For the smooth operation, it needs good management to control its daily activities through the management committee. In a cooperative, a management committee involves a process of reaching consensus and then following through with the group’s decision. Management is therefore, crucial in the implementation of policies and activities which continuously enhance the operations of the cooperatives. Cooperatives being a democratic organization are likely to experience management problems which can lead to organizational failure when the cooperative fails to adopt the most efficient policies for their members. Fulton (2001) claims that management problems occur when cooperatives fail to elect an efficient management committee. The management committee is the highest elected executive institution in a cooperative enterprise. It approves all the activities that need to be carried out by the cooperatives. Committee members are not paid for their services and the time they devote to meetings is limited. Figure 1 Conceptual Framework Figure 1 Conceptual Framework Scientific Theory of Management Every member of the cooperative may present matters (personal problems, cooperative problems or public affairs) for discussion, but only a limited number of subjects can be considered in the twice weekly meetings of the management committee. Sustainability of Agricultural Cooperatives  Years of operation  Number of branches opened  Increase of profits Independent variable Managerial Skills According to Hambrick and Mason (1984) management refers to the process of planning, organizing, leading and controlling the efforts of organization members and of using all other organizational resources to achieve stated organizational goals. On the other hand, Veerakumaran (2006), sees “management as the driving force in cooperative endeavours that assist in achieving compromises among participants, taking into account both the interests and the needs of the members, which are often short-term interests as well as the long-term commercial goals (sustainability and reducing risks) of the cooperative enterprise”. An AC is an organization that needs management like other entities. On its own it is a Cooperatives are democratic organizations and are likely to experience management problems that may lead to organizational failure. Cooperatives fail to adopt the most efficient policies for their members. It has already been stated that, management problems occur when cooperatives fail to elect an efficient management committee with relevant managerial skills (Fulton, 2001). They encounter various managerial problems that include poor financial management, poor credit control (that leads to unpredictable cash flow) and - 278 - reciprocity, which is particularly important in monitoring and sanctioning free riding behavior (Pelling& High, 2005). In order to work equitably and conform to co-operative values and principles, some pre-conditions are required, according to Munkner (2012) these include: knowledge, skills and investment in members’ education. Informed and skilled members are more likely to understand and be committed with the co-operative business. Smith, Puga, &MacPherson (2005) and Majurin (2012) also argue that members that understand or are familiar with the co-operative values are more likely to promote the inclusion of, often marginal, groups such as women and youth within cooperatives enterprises. lack of marketing (resulting in unresponsive attitudes to customer requirements), management and members’ weaknesses, failure to delegate and train cooperative members and resistance to outside advice. A problem of corruption in Kenya’s ACs management has also been reported. Some of the cooperative management problems reported besides corruption included illiteracy and lack of management skills for the members and their committees (Citation). Stakeholder Involvement The activities that encompass member participation in a cooperative include attending meetings, serving on committees, involvement in recruitment and patronage (Osterberg&Nilson, 2009). The participation of members in governance of a cooperative is what differentiates cooperative from other businesses organizations. Participation is an important indicator in developing members in understanding and appreciating of the cooperative (Gray, Karaenzle& USDA, 1998) Access to Finance Agricultural cooperative credit has long been identified as a major input in the development of the agricultural sector. Credit is viewed as more than just another resource such as labor, land, equipment and raw materials (Rahji, 2000). One of the reasons for the decline in the contribution of agriculture to the economy is lack of a formal national credit policy and paucity of credit institutions, which can assist farmers. Credit access helps to expand farmland size and production. (Olagunju, 2000) affirmed that credit facilities as well as the use of agricultural capital and labor resources accelerate the adoption process and expand the scale of production. The availability of credit occupies a central place of development strategies. (Jia, 2006). Credit is important in fostering agricultural cooperative development. The literature suggests that a membership participation inspired by cooperative values is crucial for co-operative sustainability. A number of writers have argued that co-operatives’ sustainability depends on members’ sense of identity, commitment and cohesion (Birchall, 2011; Mazzarol et al., 2011; Mu¨nkner, 2012). As Munkner2015) notes: ‘co-operatives are good as their members make them’. However membership loyalty and commitment depend on cooperatives’ ability to meet members’ needs and demands. (Olagunju, 2000) affirmed that credit facilities as well as the use of agricultural capital and labor resources accelerate the adoption process and expand the scale of production. The availability of credit occupies a central place of development strategies. (Jia, 2006). Credit is important in fostering agricultural cooperative development. Government and donors spend billions of shillings supporting credit activities for agricultural cooperatives in low income countries. Most of these activities are justified by the impact that loans have on ultimate borrowers: credit demand filled, additional crops produced, changes in modern inputs use and borrowers’ increased income. This is because in case of nil or poor return from Satisfied members are less likely to be free riders (Birchall, 2012; Munkner, 2012). Trust and reciprocity between members are also conducive to loyalty, which is needed when co-operatives experience financial instability (i.e. insufficient market demand, low prices). The literature argues that trust reinforces norms of generalized - 279 - agriculture, farmers can use credit to restart. In Kenya, there are both formal and informal credit sectors, but there is a large interest rate difference. Access to Finance This has led to banks giving unsecured loans unlike in the past when collateral security was necessary. Cooperative societies on the other hand have opened up their lending by refinancing old loans and new innovative loans on household equipment and furniture. This competition has brought new innovations and created opportunities to members to enhance their well-being (Mudibo, 2009). According to Michael Porter five competitive forces model, firms have to continually scan the internal and external business environment so as to maintain or increase their market share (Pearce and Robinson 2009). This will determine the long run profit attractiveness of the market or market segment. The ability of the firm to sustain competitive advantage in an intense rivalry market segment is very important to that company. The entrance of NGO, Micro-Finance Institutions and the shift in focus among some commercial banks to tap into the micro and small enterprise niche has brought to bear for the SACCOs that there are more niches in rural areas than just the agricultural sector. In a bid to remain competitive, these rural SACCOs are aligning themselves to serve a wider range of clientele, including salaried groups –e.g. teachers, civil servants; micro and small entrepreneurs; institutions, all of who play a role in rural economies. Banks and micro-finance Institution continue to compete with cooperative societies for the same savings from the employees (Mudibo, 2009). This competition is very intense and as such, each has to come up with superior products to attract more deposits. This has led to banks giving unsecured loans unlike in the past when collateral security was necessary. Cooperative societies on the other hand have opened up their lending by refinancing old loans and new innovative loans on household equipment and furniture. This competition has brought new innovations and created opportunities to members to enhance their well-being (Mudibo, 2009). Sustainability of Agricultural Cooperatives Competitive Environment Competition is the ability of the firm to increase or maintain its market share of its products or services, which is always under threat by other firms in the same industry. Competition is important because good competition brings about quality goods and services, innovation and efficiency in provision of goods and services. The nature and degree of competition in an industry hinge on the five forces model, the threat of new entrants, the bargaining power of customers, the bargaining power of suppliers and the threat of substitute products or services. (Pearce and Robinson 2009) argues that Access to Finance for company to deal with these forces and grow despite their effects, it must understand how they work in its industry and how they affect the company in its particular situation. On average, credit to agricultural cooperatives is estimated at less than 10% of the total credit provided through the domestic financial system. (Nyangito, et al., 2004) Credit access is not only affected by interest rate but by all characteristics of credit. This study attempts to find out how all credit factors in totality affect agricultural cooperatives access to credit. Before market liberalization in Kenya, formal agricultural credit was provided at subsidized rates through the Agricultural Finance Corporation (AFC). However, this parastatal experienced difficulties in recovering loan advances and had to stop lending at subsidized rates. Even then AFC lending rates have remained lower than commercial rates and are more stable. Although banks are legally required to lend between 17% and 20% of their loan portfolio to the agriculture sector, the local banking system has been conservative in lending to agriculture. This is probably owing to risks in agricultural production. The situation has been worsened by liberalization of interest rates and lending policies. These have made it difficult for small scale farmers to access credit. According to Michael Porter five competitive forces model, firms have to continually scan the internal and external business environment so as to maintain or increase their market share (Pearce and Robinson 2009). This will determine the long run profit attractiveness of the market or market segment. The ability of the firm to sustain competitive advantage in an intense rivalry market segment is very important to that company. The entrance of NGO, Micro-Finance Institutions and the shift in focus among some commercial banks to tap into the micro and small enterprise niche has brought to bear for the SACCOs that there are more niches in rural areas than just the agricultural sector. In a bid to remain competitive, these rural SACCOs are aligning themselves to serve a wider range of clientele, including salaried groups –e.g. teachers, civil servants; micro and small entrepreneurs; institutions, all of who play a role in rural economies. Banks and micro-finance Institution continue to compete with cooperative societies for the same savings from the employees (Mudibo, 2009). This competition is very intense and as such, each has to come up with superior products to attract more deposits. Sustainability of Agricultural Cooperatives The word sustainability is derived from the Latin sustinere(sus, up; tenere, to hold) (Atkinson, Dietz - 280 - &Neumayer, 2007). It is the long-term continuity of an enterprise or keeping the enterprise going over time (Bookchin, 2007). Sustainability is a call to action, a task in progress or “journey” and therefore a political process. It can also refer to a future intention; “sustainable business” is not necessarily a current situation but a goal for the future, a prediction (Ngugi, 2012). It has also been described as a “dialogue of values” that defies consensual definition (Blackburn, 2007). product quality; and for competing with other players in the market Several studies have revealed that the effect of un- democratic processes on member’s participation. Osterberg & Nilson (2009) found that there was significantly higher member disloyalty, when members were dissatisfied with their cooperative’s management. Borgen (2001) reported that a member is seen to be more loyal to decisions in which s/he has participated actively, rather than the decisions in which were forced on him/ her. Osterrberg and Nilson (2009) observed that members considered democratic control to be more crucial and further argued that this indicates that members regard the cooperative as a social institution, as much as an economic one. This shows the importance of having a well-functioning democracy within the cooperative governance. The more the members participate in their cooperative, the more they will be committed to their cooperative. Sustainability problems experienced by cooperative management in the whole world are almost the same. These problems result in incompetent and poor service delivery (Chaddad and Cook, 2000). Even cooperatives which are doing well are still facing many problems. “These problems include, among others poor management, lack of capital resources, inadequate training, lack of communication and participation among members, unclear and inadequate government policies on the development of agricultural cooperatives and weak linkages among the activities of the production, credit and marketing cooperatives (Prakash, 2003)”. A number of studies have pointed out that there is a relationship between member commitment and sustainability of a cooperative. According to Fulton et al (2001), noted that member commitment is linked to the cooperatives ability to develop a reputation, as an effective agent for the members. Members should be able to see the cooperative as addressing their needs. Fulton and Giannaks (2001) concluded that cooperatives must be increasingly aware of these feedback effects and manage them accordingly. Sustainability of Agricultural Cooperatives The authors noted that success of cooperative as being all effective agent for members is likely to result to increased member commitment. Empirical review According to Nkhoma (2011), several studies have shown that lack of adequate management skills in management has contributed to cooperatives failure. Keeling, Carter and Sexton (2009) conducted a study of the Rice Growers Association in California and found out that the closure of this organization was primarily due to lack of board oversight and education, coupled with ineffective management and passive membership. Nyoro and Ngugi (2007) identified that successful cooperatives had staff and management committee, with relatively higher qualifications than unsuccessful cooperatives. Management with required skills will be able to strategize on business volume, type of product and Studies such as those of Bataille-Chedotel and Huntzinger (2004), which analyses the typology of co-operative managers according to their origin, training, length of stay in the post and relation with - 281 - Kothari (2004) observed that research design is a blue print which facilitates the smooth sailing of the various research operations, thereby making research as efficient as possible hence yielding maximum information with minimal expenditure of effort, time and money. This study used descriptive research design. This design refers to a set of methods and procedures that describe variables. social value creation, or Cornforth (2006), which establishes different models of manager, centre on the power of managers. Along the same lines, Spear (2004) points out that compared to managers in capitalist companies, co-operative managers enjoy positions of far greater power and much wider margins of discretion, unfettered by the membership, as the attendance rates at the Annual General Assemblies of members tend to decrease with the age and size of the organization. Again, Akella and Greenbaum (1988) highlight the co- operatives’ greater permissiveness towards expense preference behavior, in other words, the members have a high tolerance of management power. This behavior is accentuated with a diffuse membership (diffused ownership), which tends to trust in government regulation and is not prepared to bear the cost of effective control. These tensions have an impact on the co-operatives and alter the above- mentioned balances, resulting in shortcomings in co-operative governance Target Population Kothari (2004) described population as the entire group of individuals or items under consideration in any field of inquiry and have a common attribute. The target population the study was 750 staff (senior and middle level management) of agricultural cooperatives in Machakos County. Sample and Sampling Technique A sample size is a set of observations drawn from a population by a defined procedure (Mugenda, 2008).The manual calculation method to be used to arrive at the sample size using the following formula: Sample Size = n / [1 + (n/population)] In which n = Z * Z [P (1-P)/ (D*D)]. Where, P = True proportion of factor in the population, or the expected frequency value D = Maximum difference between the sample mean and the population mean Or Expected Frequency Value minus (-) Worst Acceptable Value Z = Area under normal curve corresponding to the desired confidence level For our study therefore our sample will be: n/ [1 + (n) (E) 2 where n is the total population (750), E is the level of significance. 750/ [1 + (750) (0.05x0.05) = 110. Our sample size therefore was 110. Gabre-Mahdhin (2006) argued that information asymmetry and opportunistic behavior, which act as determinants of transaction costs related to contract enforcement, leads to enforcement related costs. Fafchamps and Gabre-Mahdhin (2001), in an extentnsive survey of traders in Malawi and Benin, found incidences of contract non-perfomance, by up to 41% in Malawi. Coutre and Onumah (2002), also identified that lack of supportive framework and disabling policies are amongst the issues that affect development of market institutions such as agricultural cooperatives. Research Instruments& Data Collection Procedure This chapter specifies the nature of the research design and the population studied. The study relied mainly on primary data. The researcher used questionnaire as the research instrument. The study utilized questionnaire that was developed for generating information on key Research Design Pilot Study According to Bordens& Abbott (2008), pilot study is as a small-scale version of the study used to establish procedures, materials and parameters to be used in the full study. Pilot study was conducted in determining if there were flaws, limitations, or other weaknesses within the data collection instrument to make the necessary revisions prior to the implementation of the study. This study took 1% of the population that was not part of the sample for pilot test. A pilot study was undertaken on at least 27 respondents and the findings of the pilot study were be included in the actual study Work Experience The study sought to establish how long the respondents had been in the respective agricultural cooperatives, this was to ascertain to what extent Research Design - 282 - From the data collected, out of the 110 questionnaires administered, 80 questionnaires were fully completed and returned making a response percent of 72.27%. This percentage concurs with Mugenda and Mugenda (2003) who argues that for generalization a response rate of 50% is adequate for analysis and reporting, 60% is good and a response rate of 70% and over is excellent, thus 72.27% was adequate for analysis. variables of interest from the targeted respondents in the study. Secondary data was obtained from literature sources or data collected by other people for some other purposes. Age Distribution The study went further to establish the distribution of the respondents’ age. The findings were as indicated in Figure 4.3. From the findings, majority (45%) indicated that they ranged between 41-50 years, followed by those who indicated that they are 51 and above years at 35% with few (15%) and (5%) and indicating that they were 31-40 years and 20-30 years respectively. Level of Education The respondents were requested to indicate their highest level of academic qualifications. The study established that majority (45%) indicated that they had university first degree, followed by those who indicated that they had diploma at (35%), certificate with 3%, few (15%) indicating that they had master’s degree and (5%) doctorate qualification respectively and this implies that respondents were well educated and that they were in a position to respond to research questions with ease. Data Analysis and Presentations The study collected both qualitative and quantitative data. Qualitative data was applicable since meanings was based on expressions through words and analysis was conducted through the use of content analysis. Quantitative data was applicable since meanings derived from numbers and analysis conducted through the use of diagrams and statistics. Gender Distribution The research went further to establish the gender of the respondents The findings as indicated a simple majority (53%) were male respondents with (47%) being females respondents. DATA ANALYSIS, PRESENTATION AND DISCUSSION This chapter presents the results of the study, data analysis and discussion. The current study sought to establish the drivers of sustainability of agricultural cooperatives in Kenya. The specific variables of the study were: managerial skills, stakeholder involvement, access to finance and competitive environment. Response Rate - 283 - sustainability their responses could be relied upon to make conclusions for the study based on experience. The findings as indicated a simple majority (40%) of the respondents indicated that they had been in the agricultural cooperatives for a period ranging from 1-10 years followed by those who indicated that they had been in the agricultural cooperatives for a period of 10-20 years at 30%, (20%) indicating that they had less than one year and with only few (10%) indicating that they had been in agricultural cooperatives for a period more than 20 years. agricultural of about cooperativesprograms often empowers them and promotes meaningful participation by diverse stakeholder groups which avail to the sustainability of agricultural cooperativessufficient and relevant information useful for the exercise . Competitive Environment The research requested the respondents to indicate whether product differentiation influenced performance of projects established which could affect sustainability of agricultural cooperatives. From the study results in 66% of the respondents stated that it increased the number of the proposed projects, 64% of the respondents stated that it increased the number of successfully completed/delivered project and 68% posited that it led to sustainability of established projects. This can be deduced that product differentiation influence performance of projects established which affect sustainability of agricultural cooperatives. Managerial Skills The research sought to find out whether technical skills did increase influence the years of operation of the cooperatives. Respondents stated that it increased the number of the completed cooperatives projects, 70% stated that it increases the number of number of people served with cooperatives activities, 65% of the respondents stated that it led to sustainability of established cooperatives activities. This implies that technical skills are important to increase number of years of operation of the cooperatives. This corroborates with the study findings of Meredith & Mantel Jr (2011) who posited that leadership tasks and activities is focusing responsibility for goal attainment. Stakeholder Involvement The study sought to find out on the key stakeholders involved in management of the cooperatives .The study results showed that majority of the respondents stated that beneficiaries, 25% stated implementing staff, 44% indicated the donors and 34% of the respondents stated the government. This implies that there was no clear key stakeholders involved for effective monitoring sustainability of agricultural cooperatives The study results are in agreement with literature review by Otieno (2008) who observed that to involve stakeholders in discussions Access to Finance Based on whether cost of capital did affect sustainability of the cooperatives, 78% of the respondents stated that it increased the number of the years of operation, 60% of the respondents stated that increased the number of branches opened and 70% of the respondents stated that it increased the net value of the organization. Similarly Lindell & Hansson (2012) noted that the cost of finance is very high and collateral requirements are hard to fulfill thus affecting sustainability of the agricultural cooperatives. Sustainability of Agricultural Cooperatives The respondents were kindly requested to indicate number of years of operation of the cooperative. The study established that majority of the - 284 - respondents(75%) indicated less than 10 years of operation, 10% of the respondents stated between 11 to 15 years, 5% posited 16 to 20 years, 7% of the respondents stated 21 to 25 years and 3% of the respondents also stated over 25 years of operation. This infers that majority of the agricultural cooperatives were not sustainable since their years of operation were very few years since they were established. determine the strength and the direction of the relationship between dependent variable and the independent variables The analysis of correlation showed that between access to finance and sustainability of agricultural cooperatives there is a positive coefficient 0.602, with p-value of 0.011. It indicates that the result is significant at α =5% and that if the access to finance increases it will have a positive impact on sustainability of agricultural cooperatives. The correlation results between managerial skills and sustainability of agricultural cooperatives also indicates the same type of result where the correlation coefficient is 0.872 and a p-value of 0.001 which significant at α = 5%. The results also show that there is a positive association between competitive environment and sustainability of agricultural cooperatives where the correlation coefficient is 0.754, with a p-value of 0.009. Further, the result shows that there is a positive association between stakeholder involvement and sustainability of agricultural cooperatives where the correlation coefficient is 0.790, with a p-value of 0.002. This therefore infers that managerial skills contributed most to sustainability of agricultural cooperatives followed by stakeholder involvement in sustainability of agricultural cooperatives, then competitive environment while access to finance had the least influence on sustainability of agricultural cooperatives. The correlation matrix implies that the independent variables are very major determinants of sustainability of agricultural cooperatives as shown by their strong positive relationship with the dependent variable; sustainability of agricultural cooperatives. Correlation Analysis The coefficient of determination (R2) explains the extent to which changes in the dependent variable can be explained by the change in the independent variables or the percentage of variation in the dependent variable and the four independent variables that were studied explain 80.80% of the sustainability of agricultural cooperatives as represented by the R2. This therefore means that other factors not studied in this research contribute 19.20% to the sustainability of agricultura cooperatives. This implies that these variables are very significant therefore need to be considered in any effort to boost sustainability of agricultura cooperatives in the study area. The study therefore Table 1: Correlation Coefficients Sustainability of agricultural cooperatives Access to finance Managerial skills Stakeholder Involvement Competitive Environment Sustainability of agricultural cooperatives R 1.000 Sig. (2-tailed) . N Access to finance R .602 1.000 Sig. (2-tailed) .011 N 80 Managerial skills R .872 .908 1.000 Sig. (2-tailed) .001 .065 N 80 80 Stakeholder Involvement R .790 .142 .876 1.000 Sig. (2-tailed) .002 .001 .004 N 80 80 80 Competitive Environment R .754 .037 .046 .056 1.000 Sig. (2-tailed) .009 .000 .001 .005 N 80 80 80 80 * Correlation is significant at the 0.05 level (2-tailed) * Correlation is significant at the 0.05 level (2-tailed) * Correlation is significant at the 0.05 level (2-tailed) coefficient of determination (R2) explains the extent to which changes in the dependent variable can be explained by the change in the independent variables or the percentage of variation in the dependent variable and the four independent variables that were studied explain 80.80% of the sustainability of agricultural cooperatives as represented by the R2. This therefore means that other factors not studied in this research contribute 19.20% to the sustainability of agricultural cooperatives. This implies that these variables are very significant therefore need to be considered in any effort to boost sustainability of agricultural cooperatives in the study area. The study therefore Correlation Analysis Pearson correlation was used to measure the degree of association between variables under consideration i.e. independent variables and the dependent variables. Pearson correlation coefficients range from -1 to +1. Negative values indicates negative correlation and positive values indicates positive correlation where Pearson coefficient <0.3 indicates weak correlation, Pearson coefficient >0.3<0.5 indicates moderate correlation and Pearson coefficient>0.5 indicates strong correlation. This statistic is called a correlation coefficient(r) which indicates the relationship between the two variables and the bigger the correlation the stronger the coefficient between the two variables being compared. The direction of the relationship is also important in that if it is positive (+) it means that there is a positive relationship between the two variables and this means that when one variable increases the other variable increases or when one variable decreases the other variable also decreases. A negative relationship (-) means that as one variable decreases the other variable increase and vice versa and hence an inverse relationship. If there is no relationship the coefficient is equal to zero. Pearson’s Product - moment correlation coefficient was used to - 285 - Table 1: Correlation Coefficients Sustainability of agricultural cooperatives Access to finance Managerial skills Stakeholder Involvement Competitive Environment Sustainability of agricultural cooperatives R 1.000 Sig. (2-tailed) . N Access to finance R .602 1.000 Sig. (2-tailed) .011 N 80 Managerial skills R .872 .908 1.000 Sig. (2-tailed) .001 .065 N 80 80 Stakeholder Involvement R .790 .142 .876 1.000 Sig. (2-tailed) .002 .001 .004 N 80 80 80 Competitive Environment R .754 .037 .046 .056 1.000 Sig. (2-tailed) .009 .000 .001 .005 N 80 80 80 80 * Correlation is significant at the 0.05 level (2-tailed) Multiple Regression Analysis In addition, the researcher conducted a multiple regression analysis so as to test relationship among variables (independent) on the sustainability of agricultural cooperatives. The study applied the statistical package for social sciences (SPSS V. 21) to code, enter and compute the measurements of the multiple regressions for the study. According to the model summary Table 2, R is the correlation coefficient which shows the relationship between the indepednt variables and depedent variable. It is notable that there extists strong positive relationship between the indepedent variables and depedent variable as shown by R value (0.899). Table 3: ANOVA NB: F-critical Value = 3.765; Predictors: (Constant): Managerial skills, Access to Finance, Competitive environment and Stakeholder involvement. taking all other independent variables at zero, a unit increase in access to finance will lead to a 0.587 increase in sustainability of agricultural cooperatives.; a unit increase in managerial skills will lead to a 0.875 increase in sustainability of agricultural cooperatives, a unit increase in stakeholder involvement will lead to .806 increase in sustainability of agricultural cooperatives and a unit increase in competitive environment will lead to 0.690 increase in sustainability of agricultural cooperatives. This infers that managerial skills contributed most to sustainability of agricultural cooperatives. At 5% level of significance, access to finance had a 0.009 level of significance; managerial skills showed a 0.001 level of significance, stakeholder involvement showed a 0.006 level of significance and competitive environment showed a 0.008 level of significance hence the most significant factor was managerial skills. taking all other independent variables at zero, a unit increase in access to finance will lead to a 0.587 increase in sustainability of agricultural cooperatives.; a unit increase in managerial skills will lead to a 0.875 increase in sustainability of agricultural cooperatives, a unit increase in stakeholder involvement will lead to .806 increase in sustainability of agricultural cooperatives and a unit increase in competitive environment will lead to 0.690 increase in sustainability of agricultural cooperatives. This infers that managerial skills contributed most to sustainability of agricultural cooperatives. At 5% level of significance, access to finance had a 0.009 level of significance; managerial skills showed a 0.001 level of significance, stakeholder involvement showed a 0.006 level of significance and competitive environment showed a 0.008 level of significance hence the most significant factor was managerial skills. The study ran the procedure of obtaining the regression coefficients, and the results were as shown on the Table 4 Multiple regression analysis was conducted as to determine the relationship between sustainability of agricultural cooperatives and the four variables. As per the SPSS generated table below, the model equation would be (Y = β0 + β1X1 + β2X2 + β3X3 + β4X4 +ε) becomes: Y= 45.098+ 0.587X1+ 0.875X2+ 0.690X3 + 0.806X4. Multiple Regression Analysis In addition, the researcher conducted a multiple regression analysis so as to test relationship among variables (independent) on the sustainability of agricultural cooperatives. The study applied the statistical package for social sciences (SPSS V. 21) to code, enter and compute the measurements of the multiple regressions for the study. According to the model summary Table 2, R is the correlation coefficient which shows the relationship between the indepednt variables and depedent variable. It is notable that there extists strong positive relationship between the indepedent variables and depedent variable as shown by R value (0.899). The identifies variables as critical determinants of sustainability of agricultural cooperatives in the study area. Table 2: Model Summary Model R R Square Adjusted R Square Std. Error of the Estimate 1 .899 .808 .605 .008 Further, the study revealed that the significance value is 0.001which is less that 0.05 thus the model is statistically significance in predicting how managerial skills, access to finance, competitive environment and stakeholder involvementaffect sustainability of agricultural cooperatives. The F critical at 5% level of significance was 20.023. Since F calculated (20.023) is greater than the F critical (value = 3.765), this shows that the overall model was significant. Table 3: ANOVA Model Sum of Squares Df Mean Square F Sig. 1 Regression 16.980 4 4.245 20.023 .001a Residual 15.987 75 .2120 Total 32.967 79 NB: F-critical Value = 3.765; Predictors: (Constant): Managerial skills, Access to Finance, Competitive environment and Stakeholder involvement. The study ran the procedure of obtaining the taking all other independent variables at zero, a unit increase in access to finance will lead to a 0.587 identifies variables as critical determinants of sustainability of agricultural cooperatives in the study area. Table 2: Model Summary Model R R Square Adjusted R Square Std. Error of the Estimate 1 .899 .808 .605 .008 Further, the study revealed that the significance value is 0.001which is less that 0.05 thus the model is statistically significance in predicting how managerial skills, access to finance, competitive environment and stakeholder involvementaffect sustainability of agricultural cooperatives. The F critical at 5% level of significance was 20.023. Since F calculated (20.023) is greater than the F critical (value = 3.765), this shows that the overall model was significant. Multiple Regression Analysis 1 Further, the study revealed that the significance value is 0.001which is less that 0.05 thus the model is statistically significance in predicting how managerial skills, access to finance, competitive environment and stakeholder involvementaffect Table 3: ANOVA Model Sum of Squares Df Mean Square F Sig. 1 Regression 16.980 4 4.245 20.023 .001a Residual 15.987 75 .2120 Total 32.967 79 NB: F-critical Value = 3.765; Predictors: (Constant): Managerial skills, Access to Finance, Competitive environment and Stakeholder involvement. Table 3: ANOVA Table 3: ANOVA Error Beta 1 (Constant) 45.098 .223 2.615 .007 Access to finance .587 .293 .402 3.098 .009 Managerial skills .875 .150 .554 7.087 .001 Competitive environment .690 .247 .416 6.008 .008 Stakeholder Involvement .806 .273 .463 6.546 .006 with Sacco activities and led to sustainability of Model with Sacco activities and led to sustainability of established Sacco activities, increases the number of the clients, net value of the Sacco increases and members take loans with interests. Further, the study revealed that the variable(Pearson correlation coefficient =.0.875) and p-value (0.001 < 0.05) statistically, strongly and significantly correlated to sustainability of agricultural cooperatives at 5% level of significance as it had a positive relationship with the dependent variable. This reveals managerial skills are an important factor that can enhance sustainability of agricultural cooperatives in the study area. This also reveals that the more managerial skills improves the more the sustainability of agricultural cooperatives in the study area Therefore, from these quantitative results it can be deduced that the study which sought to establish the influence of managerial skills on sustainability of agricultural cooperatives in the study area was achieved because it established that managerial skills influenced sustainability of agricultural cooperatives. SUMMARY, CONCLUSIONS AND RECOMMENDATIONS This chapter presents the summary of the study as guided by specific objectives, research questions and conclusions reached based on the findings and recommendations for establishing drivers of sustainability of agricultural cooperatives in Kenya as well as recommendations for further research Summary of the Findings Objective 1: To find out how managerial skills influence sustainability of agricultural cooperatives in Kenya Table 3: ANOVA This indicates that sustainability of agricultural cooperatives = 45.098 + 0.587(Access to finance) + 0.875(Managerial skills) + 0.690(Competitive Environment) + 0.806 (Stakeholder Involvement).According to the regression equation established, taking all factors into account (access to finance, managerial skills, competitive environment, stakeholder involvement) constant at zero sustainability of agricultural cooperatives was 45.098. The data findings analyzed also shows that - 287 - Table 4: Regression Coefficient Results Model Unstandardized Coefficients Standardized Coefficients t P-value. B Std. Error Beta 1 (Constant) 45.098 .223 2.615 .007 Access to finance .587 .293 .402 3.098 .009 Managerial skills .875 .150 .554 7.087 .001 Competitive environment .690 .247 .416 6.008 .008 Stakeholder Involvement .806 .273 .463 6.546 .006 SUMMARY, CONCLUSIONS AND RECOMMENDATIONS This chapter presents the summary of the study as guided by specific objectives, research questions and conclusions reached based on the findings and recommendations for establishing drivers of sustainability of agricultural cooperatives in Kenya as well as recommendations for further research Summary of the Findings Objective 1: To find out how managerial skills influence sustainability of agricultural cooperatives in Kenya From study results as the respondents stated that they mostly met annually to discuss the sustainability of agricultural cooperativesand senior level management does not frequently meet affecting decision making in regard to sustainability of agricultural cooperatives. The study established that leadership, planning and organizing increases the number of the completed Sacco projects, with Sacco activities and led to sustainability of established Sacco activities, increases the number of the clients, net value of the Sacco increases and members take loans with interests. Further, the study revealed that the variable(Pearson correlation coefficient =.0.875) and p-value (0.001 < 0.05) statistically, strongly and significantly correlated to sustainability of agricultural cooperatives at 5% level of significance as it had a positive relationship with the dependent variable. This reveals managerial skills are an important factor that can enhance sustainability of agricultural cooperatives in the study area. This also reveals that the more managerial skills improves the more the sustainability of agricultural cooperatives in the study area Therefore, from these quantitative results it can be deduced that the study which sought to establish the influence of managerial skills on sustainability of agricultural cooperatives in the study area was achieved because it established that managerial skills influenced sustainability of agricultural cooperatives. Table 4: Regression Coefficient Results Model Unstandardized Coefficients Standardized Coefficients t P-value. B Std. Objective 2: To determine how stakeholder involvement influence sustainability of agricultural cooperatives in Kenya From the descriptive analysis, the respondents stated that it increased the number of the proposed projects, increased the number of successfully completed/delivered projects and led to sustainability of established projects. This implies that cost of capital and collateral affected sustainability of agricultural cooperatives. The study also established that conditions were too stringent, corruption in giving out funds, it required security and the process was too technical.The collateral availability affect sustainability of the organizations as it increases the number of the years of operation, increases the number of number of branches opened and increases the net value of the organization. The access to financial medium (financial facilitation) equally affect sustainability of the cooperatives. Further, the study revealed that the variable(Pearson correlation coefficient =.0.602) and p-value (0.005 < 0.05) statistically, strongly and significantly correlated to sustainability of agricultural cooperatives in the study area at 5% level of significance as it had a positive relationship with the dependent variable. This reveals access to finance is an important factor that can increase sustainability of agricultural cooperatives in the study area. This also reveals that the access to finance is the more sustainability of agricultural cooperatives. Therefore, from these quantitative results it can be presumed that the study which sought to establish the influence of access to finance on sustainability of agricultural cooperatives was achieved because it established that access to finance influenced sustainability of agricultural cooperatives in the study area. bj i bli h h i i From the descriptive analysis, the study results revealed that majority of the respondents indicated stakeholder involvement affect sustainability of agricultural cooperatives in Kenya. The key stakeholders involved in monitoring and evaluation of the projects include beneficiaries, implementing staff, donors, government and they normally have stakeholder meetings on monitoring and controlling the activities of the projects yearly. The stakeholders involved carrying out monitoring and evaluation activities of the projects are rarely adequate and different stakeholders have different reporting requirements which are lenient and demonstrating the long term impact of M & E of the projects to stakeholders is rarely straightforward. Further, the study revealed that the variable(Pearson correlation coefficient =.790) and p-value (0.002< 0.05) statistically, strongly and significantly correlated to sustainability of agricultural cooperativesat 5% level of significance as it had a positive relationship with the dependent variable. This reveals that stakeholder involvement is an important factor that can boost effective sustainability of agricultural cooperatives. Objective 2: To determine how stakeholder involvement influence sustainability of agricultural cooperatives in Kenya This also reveals that the more stakeholder involvement becomes the more the sustainability of agricultural cooperatives Therefore, from these quantitative results it can be deduced that the study which sought to establish the influence of stakeholder involvement on effective sustainability of agricultural cooperatives was achieved because it established that it influenced sustainability of agricultural cooperatives. Objective 3: To examine how access to finance Objective 1: To find out how managerial skills influence sustainability of agricultural cooperatives in Kenya From study results as the respondents stated that they mostly met annually to discuss the sustainability of agricultural cooperativesand senior level management does not frequently meet affecting decision making in regard to sustainability of agricultural cooperatives. The study established that leadership, planning and organizing increases the number of the completed Sacco projects, increases the number of number of people served Objective 2: To determine how stakeholder involvement influence sustainability of agricultural cooperatives in Kenya Objective 4: To establish how competitive environment influence sustainability of agricultural cooperatives in Kenya Objective 3: To examine how access to finance influence sustainability of agricultural cooperatives in Kenya Objective 3: To examine how access to finance influence sustainability of agricultural cooperatives i From the descriptive analysis, the study results showed that the respondents stated that product differentiation increased the number of the - 289 - proposed projects, number of successfully completed/delivered project and sustainability of established projects. This can be deduced that product differentiation and fair play influence sustainability of agricultural cooperatives as it increased the profitability, increased the customer base and leads to sustainability of agricultural cooperatives. To increase the competitive gap, the study established by adding greater value through innovation, routine and controlled visit to competitors and enhancing the overall in-house experience. The competition affected sustainability of agricultural cooperatives by the greater selection of products, lower prices, greater range of services, more advertisement, greater emphasis on customer satisfaction. Further, the study revealed that the variable(Pearson correlation coefficient =.0.754) and p-value (0.009< 0.05) statistically, strongly and significantly correlated to sustainability of agricultural cooperatives at 5% level of significance as it had a positive relationship with the dependent variable. This reveals competitive environment is an important factor that can boost sustainability of agricultural cooperatives. This also reveals that the more competitive environment becomes the more the sustainability of agricultural cooperatives in the organization Therefore, from these quantitative results it can be deduced that the study which sought to establish the influence of competitive environment on sustainability of agricultural cooperatives was achieved because it established that competitive environment influenced sustainability of agricultural cooperatives. agricultural cooperatives. The stakeholders involved carrying out monitoring and evaluation activities of the projects are rarely adequate and different stakeholders have different reporting requirements which are lenient and demonstrating the long term impact of M & E of the projects to stakeholders is rarely straightforward. Additionally, study results showed that the managerial skills play an important role on sustainability of agricultural cooperatives. The senior level management attends fewer meetings affecting decision making in regard to performance of the projects. The management lacks leadership, planning and organizing skills to implement the projects. This also reveals that there is need for more managerial skills to be enhanced to boost sustainability of agricultural cooperatives. Further, the study found out cost of capital and collateral affected sustainability of agricultural cooperatives. Objective 4: To establish how competitive environment influence sustainability of agricultural cooperatives in Kenya The study also established that conditions were too stringent, corruption in giving out funds, it required security and the process was too technical. Finally, the study established that competitive environment play a significant role on enhancing sustainability of agricultural cooperatives. The product differentiation increased the number of the proposed projects, number of successfully completed/delivered project and sustainability of established projects. The fair play brought by competition affected sustainability of agricultural cooperatives as it stated to be niche offer brand identification, price differentiation and incorporation of attributes (quality or price). The reasons for not winning government sustainability of agricultural cooperatives that were provided included corruption and favouritism, technical process, the hard to get relevant information, the high standard quality of work and the sustainability of agricultural cooperatives hard to get necessary financial support. The competition affected Conclusions The study established that majority of the respondents indicated stakeholder involvement affect sustainability of agricultural cooperatives in Kenya. The key stakeholders involved in monitoring and evaluation of the projects did not meet adequately thus hindering sustainability of - 290 - Further, in relation to cooperative marketing theory, the specifying objectives and organizational structures for cooperatives that address the concerns of access to finance for agricultural producers in a context of achieving sustainability role for cooperatives capture a larger share of industry earnings for the membership, but additionally, contribute to market or industry efficiency. In other words, the external effects of organization to the internal or micro aspects of organizing and sustaining cooperation should have sound leadership in the cooperative movement and connects proper leadership and sound governance to a satisfied cooperative membership, proper financial management and a thriving cooperative movement to access finance to run cooperative activities to ensure its sustainability. The study found out cost of capital and collateral affected sustainability of agricultural cooperatives. The study also established that conditions were too stringent, corruption in giving out funds, it required security and the process was too technical. The policies on access to funds should be enhanced to promote sustainability of the cooperatives. performance of the projects by the greater selection of products, lower prices, greater range of services, more advertisement, greater emphasis on customer satisfaction. Recommendations The study recommends for involvement of all stakeholders to boost sustainability of agricultural cooperatives. The key stakeholders should meet adequately in carrying out monitoring and evaluation activities of the projects that are rarely adequate whereby different stakeholders have different reporting requirements. In regard to Co- operative movement theory, there is need to ensure that there is to bring all stakeholders on board for the success of an organization as every individual's personal environment, and then improved circumstances would lead to goodness. If people are motivated and given the impetus to apply themselves through creation of fair policies and equitable environment when included in the running an organization activities, then even their attitude to work will change and a new era of flourishing social and economic movements will be witnessed for the sustainability of the organization. Finally, the study recommends for amendment on policies in regard to competitive environment as it play a significant role on enhancing sustainability of agricultural cooperatives. The product differentiation should be enhanced and fair play brought by competition can lead to the greater selection of products, lower prices, greater range of services, more advertisement, greater emphasis on customer satisfaction aimed at enhancing sustainability of agricultural cooperatives. According to cooperative dynamic theory, cooperative and mutual organizational forms arise for reasons that include contracting problems and stiff completion between parties. The cooperative always work in a dynamic environment that requires the government to specifically formulate policies to regulate, Additionally, study recommends for the management to be trained on the managerial skills as they play an important role sustainability of agricultural cooperatives. The senior level management should increase meetings affecting decision making in regard to sustainability of agricultural cooperatives.The training should focus on leadership, planning and organizing skills. According to the scientific theory of management the efficient accomplishment of work tasks depends on proper management. The primary consideration should be based on training of staff on marketing and management of cooperatives as well as influence of other services offered by cooperatives. - 291 - supervise and protect them from stiff competition for their sustainability purposes. concentrated on employee behavior, satisfaction, dissatisfaction and commitment in sustainability of agricultural cooperatives. This study therefore highlights the role of managers and stakeholders in sustainability of agricultural cooperatives, an area that has not been much explored. Recommendations for Further studies A review of literature indicated that there has been limited amount of research on drivers of sustainability of agricultural cooperatives in the Kenyan context. Thus, the findings of this study serve as a basis for future studies on sustainability of agricultural cooperatives and on this population. Sustainability of agricultural cooperatives, has not been widely studied which presents gaps in African and Kenyan contexts. The study has contributed to knowledge by establishing that managerial skills, stakeholder involvement and access to finance influence sustainability of agricultural cooperatives of this population in the Kenyan context. This study used qualitative and quantitative techniques. It was also a cross sectional study and hence other studies using longitudinal design could be carried out to establish whether turnover cognitions are actualized. Also, an exploratory study would enrich findings because such a study would have a wide range of factors that sustainability of agricultural cooperatives addressed other than the ones identified in this study. Interaction effects should be investigated. The interaction effects may be re-examined at a later period because of the constant changes that take place in organizations. Some of the findings have generally vindicated the long held positions regarding the various relationships that were studied. Other findings, however, such as the role of training and remuneration in sustainability of agricultural cooperatives were inconsistent with pertinent literature and results of previous studies thus preparing ground for paradigm shift in such factors in relation to this population. This study confined itself to the agricultural cooperatives in Machakos County, Kenya. A comparative study should be carried out to compare whether the findings also apply for agricultural cooperatives in other counties Kenya in order to validate whether the findings can be generalized to others in Kenya. Additionally, the study did not tie the determinants as the only drivers of sustainability of agricultural cooperatives. Thus, there is need to undertake another research to examine the other factors which could be influencing sustainability of agricultural cooperatives in Kenya. The research has clearly pointed out the role of managerial skills and stakeholder involvement especially the members in sustainability of agricultural cooperatives. Studies have - 292 - Gordon, J. 2004. "Non-traditional Analysis of Co-operative Economic Impacts: Preliminary Indicators and a Case Study". Review of International Co-operation97(1):6-47. REFERENCES Bataille-Chedotel, F Y Huntzinger F (2004) “Directivos y gobierno de lascooperativasobreras de producción”,CIRIEC-España, no 48. Bataille-Chedotel, F Y Huntzinger F (2004) “Directivos y gobierno de lascooperativasobreras de producción”,CIRIEC-España, no 48. Bendick, M and M.L. Egan.2005. “Worker Ownership and Participation Enhances Economic Development in Low- Opportunity Communities”. Journal of Community Practice2(1):61-85. Birchall, J. (2004), Co-operatives and the Millennium Development Goals, ILO, Brennan, M.A. and A.E. Luloff. 2005. “A Cooperative Approach to Rural Development in Ireland: Cultural Artifacts and the Irish Diaspora as an Example”. Journal of International Agricultural and Extension Education. (forthcoming). Cawley, M., S. Gaffey, and D. Gilmor. 1999. "The Role of Quality Tourism and Craft SMEs in Rural Development: Evidence from the Republic of Ireland". Anatolia: An International Journal of Tourism and Hospitality Research10(1):45-60. Chambers, R & Conway, G. (2006) Sustainable rural livelihoods: Practical concepts for the 21 st century. IDS Discussion Paper 296. Brighton: IDS. Chaves, R and Sajardo, A (2004) “Social Economy Managers: between values and entrenchment”, Annals of Public and Cooperative Economics, Vol 75, No 1, pp139-161 Christenson, J.A. and J.W. Robinson. 1986. Community Development in Perspective. Ames, IA: Iowa State University Press. Coggon D. Rose G. and Barker D. (1997).Epidemiology for the Uninitiated: Case-control and cross sectional studies. British Medical Journal Cornforth, C (ed) (2006) The governance of non-profit organisations, Routledge, Londres. Duncombe, R &Heeks, R. (2005) Information & Communication Technologies (ICTs), Poverty Reduction and Micro, Small & Medium-scale Enterprises (MSMEs): A framework for understanding ICT applications for MSMEs in developing countries, Institute for Development Policy and Management (IDPM). TheUniversity of Manchester. Evans, A. C. (2002), The Unpaved Road Ahead: HIV/AIDS & Microfinance: An Exploration of Kenya Credit Unions (SACCOs), Research Monograph Series No. 21, World Council of Credit Unions, Madison, Wisconsin Evans, A. C. (2002), The Unpaved Road Ahead: HIV/AIDS & Microfinance: An Exploration of Kenya Credit Unions (SACCOs), Research Monograph Series No. 21, World Council of Credit Unions, Madison, Wisconsin Gordon, J. 2004. "Non-traditional Analysis of Co-operative Economic Impacts: Preliminary Indicators and a Case Study". Review of International Co-operation97(1):6-47. Gordon, J. 2004. "Non-traditional Analysis of Co-operative Economic Impacts: Preliminary Indicators and a Case Study". Review of International Co-operation97(1):6-47. - 293 - Hulme, K. and Edwards, P. (2004) “Governance in democratic member-based organisations”, Annals of Public and Cooperative Economics, Vol 75, No 1, pp33-59. International Cooperative Alliance (2004) http://www.coop.org/ Accessed on 2 March 2008. REFERENCES International Monetary Fund (2007) Kenya: Poverty Reduction Strategy Annual Progress Report.2004/2005, IMF Country Report No. 07/159, International Monetary Fund. Washington, D.C. Jodahl, T. 2006. "Consumer Co-operatives in Norway".Review of International Co-operation96(1):9-16. Luloff, A.E., and J. Bridger.2006. "Community Agency and Local Development". Pp. 203-213 in, Challenges for Rural America in the Twenty-First Century, edited by D. Brown and L. Swanson. University Park, PA: Pennsylvania State University Press. Madane, M. 2002. "Co-operative Rejuvenation Through Self-help Groups and Other Alternatives". Review of International Co-operation95(1):104-114. Michels, R (1911) Political parties: a sociological study of the oligarchical tendencies of modern democracy (Spanish version: 1969, Amorrortu, Buenos Aires) Ministry of Information & Communications (2006), 2006 Kenya ICT Strategy: Collaboration & Outsourcing for Economic Growth. Mudibo, E.K. (2005), “Highlights of the SACCO movement and current trends in the Kenya Union of Savings and Credit Co-operatives (KUSCCO)’, KUSCCO, Nairobi. MungaiWainaina (2005) Using ICTs for Poverty Reduction and Environmental protection in Kenya: The “M- vironment” Approach, International Institute for Sustainable Development (IISD). Neuman, W.L (2000). Social Research Methods: Qualitative and Quantitative Allyn and Bacon Publishers Neuman, W.L (2000). Social Research Methods: Qualitative and Quantitative Approaches. Boston: Allyn and Bacon Publishers Okello, D. (2006) ‘Open Access’ An approach for building and financing pro-poor ICT infrastructure Propoor Community-driven Networks Seminar, 17 August 2006, Hotel Africana, Kampala. Phillips, R. 2004. "Artful Business: Using the Arts for Community Economic Development". Community Development Journal39(2):112-22. Republic of Kenya (2007) “Medium Term Expenditure Framework 2007/2008-2009/2010”, Report for the Agriculture and Rural Development (ARD) Sector. Research Report 177, Duffey, P. (ed.). Washington, D.C., United States Department of Agriculture: 1-4. - 294 - ds, A. (2000) ‘The Impact of New Generation Cooperatives on Their Communities.’RBS Romer, P. (1993) Ideas gap and object gaps in economic development, Journal of Monetary Economics, Vol. 32, pp. 543-573. Shragge, E and Fontan, J M (ed) (2004) Social Economy. Internacional debates and perspectives, Black Rose Books, London Spear, R (2004) “Governance in democratic member-based organisations”, Annals of Public and Cooperative Economics, Vol 75, No 1, pp33-59. Stiglitz, J.E. (2006) ‘Economic Organization, Information and Development’, in J. Behrman and T.N. Srinivasan (eds.), Handbook of Development Economics, Vol.1. Amsterdam: North Holland. The Kenya High Commission in the United Kingdom (2007) Newsletter Issue 2 - April 2007. The Ministry of Information & Communications (2006), Kenya is Running: Creating prosperity through innovation. USDA – Rural Business Cooperative Service. 2005. Marketing Cooperative by Type, Memberships and Sales. REFERENCES http://www.rurdev.usda.gov/rbs/coops/data.htm (Accessed february 4, 2013). Verma, S.K. (2004) “Cooperative Centenary in India”, New Sector Magazine, Issue No 61, April/ May 2004. Wilkinson, K.P. 2002.The Community in Rural America. New York, NY: Greenwood Press, 2002. World Bank (2000) World Development Report. New York, Oxford University Press. - 295 -
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https://zenodo.org/record/1564321/files/article.pdf
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Passifloraceae
Notizblatt des Königl. botanischen Gartens und Museums zu Berlin
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Passifloraceae Author(s): H. Harms Source: Notizblatt des Königl. botanischen Gartens und Museums zu Berlin, Bd. 6, Nr. 60, R. Pilger: Plantae Uleanae novae vel minus cognitae. Heft 5 (Sep. 20, 1915), pp. 347-348 Published by: Botanischer Garten und Botanisches Museum, Berlin-Dahlem Stable URL: http://www.jstor.org/stable/3994310 . Accessed: 15/06/2014 03:48 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp . JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. Botanischer Garten und Botanisches Museum, Berlin-Dahlem is collaborating with JSTOR to digitize, preserve and extend access to Notizblatt des Königl. botanischen Gartens und Museums zu Berlin. This content downloaded from 195.78.109.96 on Sun, 15 Jun 2014 03:48:13 AM All use subject to JSTOR Terms and Conditions - 347 This content downloaded from 195.78.109.96 on Sun, 15 Jun 2014 03:48:13 AM All use subject to JSTOR Terms and Conditions H. Harms. Passiflora selerophylla Harms n. sp. (Sect. Astrophea). - Frutex 1-2 m altus, scandens, cirrhis validiusculis, ramulis glabris vel sub- glabris (junioribus puberulis), cortice subatro-cinereo vel sordide sub- atro-brunneolo; folia breviter petiolata, petiolo crassiusculo puberulo vel subglabro, circ. 5-10 mm longo vel breviore, apice biglanduloso, ovalia vel ovata vel obovata vel oblonga, basi obtusa vel rotundata vel emarginulata vel obtusiuscula, apice obtusa vel rotundata vel breviter acuta, interdum emarginulata, saepius brevissime mucronulata, rigida, coriacea, supra nitidula glabra leviter tantum reticulata, subtus distincte elevato-reticulata et brevissime villosula, 4-7 cm longa, 3-5 cm lata; flores axillares solitarii, bini vel terni, folio breviores, pedicellati, pedicello breviter adpresse pubescente, circ. 10-15 mm vel paullo ultra longo; alabastra subaureo-sericea; receptaculum late infundibuli- forme, circ. 8-9 mm longum, cum sepalis extus breviter subsericeo- pubescens; sepala 5 anguste oblonga, obtusa vel obtusiuscula 2,3-2,5 cm longa; petala 5, lanceolata, obtusiuscula, byalina, sepalis paullo breviora, circ. 1,8 cm vel ultra longa; corona faucialis duplex, filis exterioribus petalis fere aequilongis vel ea paullo superantibus in- ferne a latere complanatis, fere medio geniculatis et sursum tenui- filiformibus et saepe flexuosis vel corrugatis (parte basali complanata sursum leviter dilatata oblique apiculata fere 1 cm longa), filis interi- oribus multo brevioribus, corona versus medium receptaculi affixa in fila numerosa fissa, circ. 3 mm alta. Guyana, Venezuela: Roraima: Auf dem unteren Campo (E. ULE n. 8667 - Dezember 1909, Bliite rotlich-braun, schwarz-purpurn ge- sprenkelt, 1-2 m hoher Strauch). - Ferner gehort hierher ein Blatt- exemplar vom siudlichen Abhang des Roraima, das RICH. SCHOMBURG n. 986 im November 1842 gesammelt bat und das unter der Bezeichnung Astrophea emarginata Roem. in Schomburgk, Reis. Brit. Guiana (1848) 1090 aufgefiihrt ist; das Herbarexemplar triagt die Bezeichnung Astrophea emaryinata Klotzsch. Passiflora leptopoda Harms n. sp. (Sect. Astrophea). - Frutex scandens (?), ramulis glabris, interdum leviter tenuiterque ut petioli cera quadam lactea afflatis; folia petiolata, petiolo glabro 0,8-1,5 cm longo, oblonga vel late lanceolata, basi rotundata vel obtusa vel levissime emarginulata, apice obtusa vel emarginulata vel breviter obtuse vel 348 obtusiuscule acuminata, chartacea, glabra, costa subtus prominula ima basi versus petiolum glandulis parvis paribus immersis praedita, circ. This content downloaded from 195.78.109.96 on Sun, 15 Jun 2014 03:48:13 AM All use subject to JSTOR Terms and Conditions H. Harms. 10-16 cm longa, 5-6 cm lata; racemi terminales (?) vel e ramulis orti, pauciflori vel pluriflori, laxi, pedicelli graciles tenuissimi penduli glabri paullo supra basin articulati ibique bracteolis 2 minimis lineari- setaceis praediti (articulatione a basi 5-8 mm distante), addita bractea minima paullulo infra articulationem inserta, basi foliis reductis angustis parvis vel raro evolutis suffulti, 4-7,5 cm longi; floris angusti glabri saepe leviter lacteo-afflati receptaculum breviter tubulosum, basi leviter inflatum et lineis intrusis saepe profundis longitudinalibus notatum, intus a corona fauciali ad basin circ. 12 mm longum; sepala 5 anguste lanceolata, circ. 5 cm longa, acuta vel obtusiuscula; petala 5 illis simi- lia sed tenuiora vix vel paullo breviora; coronae faucialis pluriseriatae series extima e filis longissimis tenuissimis, series insequens e filis multo brevioribus composita, series intima plumosa deflexa e filis brevibus densis numerosissimis formata; antherae angustae fere 1,5 cm longae; gynophorum elongatum glabrum circ. 3,5 cm longum, ovarium angustum subsericeo-pubescens. Brasilien: Rio Branco, Wald bei der Serra de Carauma (E. ULE n. 7708 - November 1908; Bliite weiB). - Brit. Guiana: Savanne (RICH. SCHOMBURGK n. 424 - Februar 1842; genannt als A8trophea glaberrima Klotzsch in Schomburgk, Reis. Brit. Guiana III. (1848) 1168: In Oasen in der Umgebung von Pirara; bliiht im Juni und Juli; windender Strauch). Die Art ist auffaullig durch die diinnen haingenden langen Blitenstiele. Die Art ist auffaullig durch die diinnen haingenden langen Blitenstiele. Von E. Ule. Von 1. (3 a). Rhynchanthera intermedia Ule n. sp. - Caulis ra- mosus, ramis dense glanduloso-hirsutis; folia breviter petiolata, mem- branacea, ovata, longiuscule acuminata vel acuta, basi rotundata vel subcordata, 7- vel 9-nervia, dense pilosa; flores in axillis foliorum breviter paniculati; calycis tubus et lobi dense pilosi, lobi tubo longiores; stamen unum ceteris multo majus, antherarum rostrum elongatum. Halbstrauchige, 1-2 m hohe Pflauze mit undeutlich vierkantigen, mittelstarken Stengeln, die auBer den dichten, langen Haaren mit rost- farbenen Filzhaaren besetzt sind. Blattstiel 1/2 1 cm lang; Bliatter
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https://aclanthology.org/2021.acl-long.321.pdf
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Reliability Testing for Natural Language Processing Systems
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Proceedings of the 59th Annual Meeting of the Association for Computational Linguistics and the 11th International Joint Conference on Natural Language Processing, pages 4153–4169 August 1–6, 2021. ©2021 Association for Computational Linguistics ∗Correspondence to: samson.tan@salesforce.com Abstract Figure 1: How DOCTOR can integrate with existing system development workflows. Test (left) and sys- tem development (right) take place in parallel, separate teams. Reliability tests can thus be constructed inde- pendent of the system development team, either by an internal “red team” or by independent auditors. Questions of fairness, robustness, and trans- parency are paramount to address before de- ploying NLP systems. Central to these con- cerns is the question of reliability: Can NLP systems reliably treat different demographics fairly and function correctly in diverse and noisy environments? To address this, we argue for the need for reliability testing and contextu- alize it among existing work on improving ac- countability. We show how adversarial attacks can be reframed for this goal, via a framework for developing reliability tests. We argue that reliability testing — with an emphasis on inter- disciplinary collaboration — will enable rigor- ous and targeted testing, and aid in the enact- ment and enforcement of industry standards. Figure 1: How DOCTOR can integrate with existing system development workflows. Test (left) and sys- tem development (right) take place in parallel, separate teams. Reliability tests can thus be constructed inde- pendent of the system development team, either by an internal “red team” or by independent auditors. Reliability Testing for Natural Language Processing Systems Samson Tan§♮∗ Shafiq Joty§‡ Kathy Baxter§ Araz Taeihagh♦♣ Gregory A. Bennett§ Min-Yen Kan♮ §Salesforce Research ‡Nanyang Technological University ♮School of Computing, National University of Singapore ♦Lee Kuan Yew School of Public Policy, National University of Singapore ♣Centre for Trusted Internet and Community, National University of Singapore Reliability Testing for Natural Language Processing Systems Samson Tan§♮∗ Shafiq Joty§‡ Kathy Baxter§ Araz Taeihagh♦♣ Gregory A. Bennett§ Min-Yen Kan♮ §Salesforce Research ‡Nanyang Technological University ♮School of Computing, National University of Singapore ♦Lee Kuan Yew School of Public Policy, National University of Singapore ♣Centre for Trusted Internet and Community, National University of Singapore Reliability Testing for Natural Language Processing Systems Samson Tan§♮∗ Shafiq Joty§‡ Kathy Baxter§ Araz Taeihagh♦♣ Gregory A. Bennett§ Min-Yen Kan♮ §Salesforce Research ‡Nanyang Technological University ♮School of Computing, National University of Singapore ♦Lee Kuan Yew School of Public Policy, National University of Singapore ♣Centre for Trusted Internet and Community, National University of Singapore 1 Introduction Initial research on evaluating out-of-distribution generalization involved manually-designed chal- lenge sets (Jia and Liang, 2017; Nie et al., 2020; Gardner et al., 2020), counterfactuals (Kaushik et al., 2019; Khashabi et al., 2020; Wu et al., 2021), biased sampling (Søgaard et al., 2021) or toolk- its for testing if a system has specific capabilities (Ribeiro et al., 2020) or robustness to distribution shifts (Goel et al., 2021). However, most of these approaches inevitably overestimate a given sys- tem’s worst-case performance since they do not mimic the NLP system’s adversarial distribution1. Reliability. Defined by IEEE (2017) as the “de- gree to which a system, product or component per- forms specified functions under specified condi- tions for a specified period of time”. We prefer this term over robustness2 to challenge the NLP community’s common framing of inputs from out- side the training distribution as “noisy”. The notion of reliability requires us to explicitly consider the specific, diverse environments (i.e., communities) a system will operate in. This is crucial to reducing the NLP’s negative impact on the underrepresented. A promising technique for evaluating worst-case performance is the adversarial attack. However, al- though some adversarial attacks explicitly focus on specific linguistic levels of analysis (Belinkov and Bisk, 2018; Iyyer et al., 2018; Tan et al., 2020; Eger and Benz, 2020), many often simply rely on word embeddings or language models for perturbation proposal (see §4). While the latter may be useful to evaluate a system’s robustness to malicious actors, they are less useful for dimension-specific testing (e.g., reliability when encountering grammatical variation). This is because they often perturb the input across multiple dimensions at once, which may make the resulting adversaries unnatural. Dimension. An axis along which variation can occur in the real world, similar to Plank (2016)’s variety space. A taxonomy of possible dimensions can be found in Table 1 (Appendix). Adversarial attack. A method of perturbing the input to degrade a target model’s accuracy (Good- fellow et al., 2015). In computer vision, this is achieved by adding adversarial noise to the image, optimized to be maximally damaging to the model. §4 describes how this is done in the NLP context. Stakeholder. A person who is (in-)directly im- pacted by the NLP system’s predictions. Stakeholder. A person who is (in-)directly im- pacted by the NLP system’s predictions. 2The “degree to which a system or component can func- tion correctly in the presence of invalid inputs or stressful environmental conditions” (IEEE, 2017). 1 Introduction Rigorous testing is critical to ensuring a program works as intended (functionality) when used un- der real-world conditions (reliability). Hence, it is troubling that while natural language technologies are becoming increasingly pervasive in our every- day lives, there is little assurance that these NLP systems will not fail catastrophically or amplify dis- crimination against minority demographics when exposed to input from outside the training distribu- tion. Recent examples include GPT-3 (Brown et al., 2020) agreeing with suggested suicide (Rousseau et al., 2020), the mistranslation of an innocuous social media post resulting in a minority’s arrest (Hern, 2017), and biased grading algorithms that can negatively impact a minority student’s future (Feathers, 2019). Additionally, a lack of rigorous testing, coupled with machine learning’s (ML) im- plicit assumption of identical training and testing distributions, may inadvertently result in systems that discriminate against minorities, who are often underrepresented in the training data. This can take the form of misrepresentation of or poorer perfor- mance for people with disabilities, specific gender, ethnic, age, or linguistic groups (Hovy and Spruit, 2016; Crawford, 2017; Hutchinson et al., 2020). Amongst claims of NLP systems achieving human parity in challenging tasks such as question answer- ing (Yu et al., 2018), machine translation (Has- san et al., 2018), and commonsense inference (De- vlin et al., 2019), research has demonstrated these systems’ fragility to natural and adversarial noise (Goodfellow et al., 2015; Belinkov and Bisk, 2018) and out-of-distribution data (Fisch et al., 2019). It is also still common practice to equate “test- ing” with “measuring held-out accuracy”, even as datasets are revealed to be harmfully biased (Wag- ner et al., 2015; Geva et al., 2019; Sap et al., 2019). Many potential harms can be mitigated by detect- ing them early and preventing the offending model from being put into production. Hence, in addition to being mindful of the biases in the NLP pipeline (Bender and Friedman, 2018; Mitchell et al., 2019; 4153 Waseem et al., 2021) and holding creators account- able via audits (Raji et al., 2020; Brundage et al., 2020), we argue for the need to evaluate an NLP system’s reliability in diverse operating conditions. (classification) or text (generation). We exclude raw language models from the discussion since it is unclear how performance, and hence worst-case performance, should be evaluated. We do include NLP systems that use language models internally (e.g., BERT-based classifiers (Devlin et al., 2019)). 1 Introduction Hence, in this paper targeted at NLP researchers, practitioners, and policymakers, we make the case for reliability testing and reformulate adversarial attacks as dimension-specific, worst-case tests that can be used to approximate real-world variation. We contribute a reliability testing framework — DOCTOR — that translates safety and fairness con- cerns around NLP systems into quantitative tests. We demonstrate how testing dimensions for DOC- TOR can be drafted for a specific use case. Finally, we discuss the policy implications, challenges, and directions for future research on reliability testing. Actor. Someone who has influence over a) the design of an NLP system and its reliability testing regime; b) whether the system is deployed; and c) who it can interact with. Within the context of our discussion, actors are likely to be regulators, experts, and stakeholder advocates. Expert. An actor who has specialized knowl- edge, such as ethicists, linguists, domain experts, social scientists, or NLP practitioners. 1The distribution of adversarial cases or failure profile. 2 Terminology Definitions The accelerating interest in building NLP-based products that impact many lives has led to ur- gent questions of fairness, safety, and accountabil- ity (Hovy and Spruit, 2016; Bender et al., 2021), Let’s define key terms to be used in our discussion. NLP system. The entire text processing pipeline built to solve a specific task; taking raw text as input and producing predictions in the form of labels 4154 prompting research into algorithmic bias (Boluk- basi et al., 2016; Blodgett et al., 2020), explainabil- ity (Ribeiro et al., 2016; Danilevsky et al., 2020), robustness (Jia and Liang, 2017), etc. Research is also emerging on best practices for productizing ML: from detailed dataset documentation (Bender and Friedman, 2018; Gebru et al., 2018), model documentation for highlighting important but of- ten unreported details such as its training data, in- tended use, and caveats (Mitchell et al., 2019), and documentation best practices (Partnership on AI, 2019), to institutional mechanisms such as audit- ing (Raji et al., 2020) to enforce accountability and red-teaming (Brundage et al., 2020) to address de- veloper blind spots, not to mention studies on the impact of organizational structures on responsible AI initiatives (Rakova et al., 2020). imize model failure, they highlight serious reliabil- ity issues for putting ML models into production since they show that these models could fail catas- trophically in naturally noisy, diverse, real-world environments (Saria and Subbaswamy, 2019). Ad- ditionally, bias can seep into the system at multiple stages of the NLP lifecycle (Shah et al., 2020), re- sulting in discrimination against minority groups (O’Neil, 2016). The good news, however, is that rigorous testing can help to highlight potential is- sues before the systems are deployed. The need for rigorous testing in NLP is reflected in ACL 2020 giving the Best Paper Award to Check- List (Ribeiro et al., 2020), which applied the idea of behavior testing from software engineering to test- ing NLP systems. While invaluable as a first step towards the development of comprehensive test- ing methodology, the current implementation of CheckList may still overestimate the reliability of NLP systems since the individual test examples are largely manually constructed. Importantly, with the complexity and scale of current models, humans cannot accurately determine a model’s adversarial distribution (i.e., the examples that cause model failure). Consequently, the test examples they con- struct are unlikely to be the worst-case examples for the model. Automated assistance is needed. 2 Terminology Definitions Calls for increased accountability and transparency are gaining traction among governments (116th U.S. Congress, 2019; NIST, 2019; European Com- mission, 2020; Smith, 2020; California State Leg- islature, 2020; FDA, 2021) and customers increas- ingly cite ethical concerns as a reason for not en- gaging AI service providers (EIU, 2020). While there has been significant discussion around best practices for dataset and model creation, work to ensure NLP systems are evaluated in a man- ner representative of their operational conditions has only just begun. Initial work in constructing representative tests focuses on enabling develop- ment teams to easily evaluate their models’ lin- guistic capabilities (Ribeiro et al., 2020) and ac- curacy on subpopulations and distribution shifts (Goel et al., 2021). However, there is a clear need for a paradigm that allows experts and stakeholder advocates to collaboratively develop tests that are representative of the practical and ethical concerns of an NLP system’s target demographic. We argue that reliability testing, by reframing the concept of adversarial attacks, has the potential to fill this gap. Therefore, we propose to perform reliability test- ing, which can be thought of as one component of behavior testing. We categorize reliability tests as average-case tests or the worst-case tests. As their names suggest, average-case and worst-case tests estimate the expected and lower-bound per- formance, respectively, when the NLP system is exposed to the phenomena modeled by the tests. Average-case tests are conceptually similar to Wu et al. (2021)’s counterfactuals, which is contem- poraneous work, while worst-case tests are most similar to adversarial attacks (§4). Our approach parallels boundary value testing in software engineering: In boundary value testing, tests evaluate a program’s ability to handle edge cases using test examples drawn from the extremes of the ranges the program is expected to handle. Similarly, reliability testing aims to quantify the system’s reliability under diverse and potentially extreme conditions. This allows teams to perform better quality control of their NLP systems and in- troduce more nuance into discussions of why and when models fail (§5). Finally, we note that reliabil- 3.1 What is reliability testing? Despite the recent advances in neural architectures resulting in breakthrough performance on bench- mark datasets, research into adversarial examples and out-of-distribution generalization has found ML systems to be particularly vulnerable to slight perturbations in the input (Goodfellow et al., 2015) and natural distribution shifts (Fisch et al., 2019). While these perturbations are often chosen to max- 4155 ity testing and standards are established practices in engineering industries (e.g., aerospace (Nelson, 2003; Wilkinson et al., 2016)) and advocate for NL engineering to be at parity with these fields. Algorithm 1 General Reliability Test Algorithm 1 General Reliability Test Require: Data distribution Dd = {X, Y} modeling the di- mension of interest d, NLP system M, Source dataset X ∼X, Desired labels Y ′ ∼Y, Scoring function S. Ensure: Average- or worst-case examples X′, Result r. 1: X′ ←{∅}, r ←0 2: for x, y′ in X, Y ′ do 3: C ←SAMPLECANDIDATES(X) 4: switch TestType do 5: case AverageCaseTest 6: s ←MEAN(S(y′, M(C))) 7: X′ ←X′ ∪C 8: case WorstCaseTest 9: x′, s ←arg minxc∈C S(y′, M(xc)) 10: X′ ←X′ ∪{x′} 11: r ←r + s 12: end for 13: r ← r |X| 14: return X′, r go t G y Require: Data distribution Dd = {X, Y} modeling the di- mension of interest d, NLP system M, Source dataset X ∼X, Desired labels Y ′ ∼Y, Scoring function S. Ensure: Average- or worst-case examples X′, Result r. 1: X′ ←{∅}, r ←0 2: for x, y′ in X, Y ′ do 3: C ←SAMPLECANDIDATES(X) 4: switch TestType do 5: case AverageCaseTest 6: s ←MEAN(S(y′, M(C))) 7: X′ ←X′ ∪C 8: case WorstCaseTest 9: x′, s ←arg minxc∈C S(y′, M(xc)) 10: X′ ←X′ ∪{x′} 11: r ←r + s 12: end for 13: r ← r |X| 14: return X′, r 3Dua et al. (2019) reports a cost of 60k USD for 96k question–answer pairs. 3.2 Evaluating worst-case performance in a label-scarce world A proposed approach for testing robustness to nat- ural and adverse distribution shifts is to construct test sets using data from different domains or writ- ing styles (Miller et al., 2020; Hendrycks et al., 2020), or to use a human vs. model method of con- structing challenge sets (Nie et al., 2020; Zhang et al., 2019b). While they are the gold standard, such datasets are expensive to construct,3 making it infeasible to manually create worst-case test ex- amples for each NLP system being evaluated. Con- sequently, these challenge sets necessarily overesti- mate each system’s worst-case performance when the inference distribution differs from the train- ing one. Additionally, due to their crowdsourced nature, these challenge sets inevitably introduce distribution shifts across multiple dimensions at once, and even their own biases (Geva et al., 2019), unless explicitly controlled for. Building individ- ual challenge sets for each dimension would be prohibitively expensive due to combinatorial ex- plosion, even before having to account for concept drift (Widmer and Kubat, 1996). This coupling complicates efforts to design a nuanced and com- prehensive testing regime. Hence, simulating vari- ation in a controlled manner via reliability tests can be a complementary method of evaluating the system’s out-of-distribution generalization ability. get model’s accuracy as the measure of success. However, this often resulted in the semantics and expected prediction changing, leading to an over- estimation of the attack’s success. Recent attacks aim to preserve the original input’s semantics. A popular approach has been to substitute words with their synonyms using word embeddings or a lan- guage model as a measure of semantic similarity (Alzantot et al., 2018; Ribeiro et al., 2018; Michel et al., 2019; Ren et al., 2019; Zhang et al., 2019a; Li et al., 2019; Jin et al., 2020; Garg and Ramakr- ishnan, 2020; Li et al., 2020a). Focusing on maximally degrading model accuracy overlooks the key feature of adversarial attacks: the ability to find the worst-case example for a model from an arbitrary distribution. Many recent attacks perturb the input across multiple dimensions at once, which may make the result unnatural. By constraining our sample perturbations to a distribu- tion modeling a specific dimension of interest, the performance on the generated adversaries is a valid lower bound performance for that dimension. Said another way, adversarial attacks can be reframed as interpretable reliability tests if we constrain them to meaningful distributions. 4 Adversarial Attacks as Reliability Tests We first give a brief introduction to adversarial attacks in NLP before showing how they can be used for reliability testing. We refer the reader to Zhang et al. (2020b) for a comprehensive survey. Existing work on NLP adversarial attacks perturbs the input at various levels of linguistic analysis: phonology (Eger and Benz, 2020), orthography (Ebrahimi et al., 2018), morphology (Tan et al., 2020), lexicon (Alzantot et al., 2018; Jin et al., 2020), and syntax (Iyyer et al., 2018). This is the key element of our approach as detailed in Alg. 1. We specify either an average (Lines 5–7) or worse case test (Lines 8–10), but conditioned on the data distribution D that models a particular dimension of interest d. The resultant reliability score gauges real-world performance and the worst- case variant returns the adversarial examples that cause worst-case performance. When invariance to input variation is expected, y′ is equivalent to the Early work did not place any constraints on the attacks and merely used the degradation to a tar- 4156 source label y. Note that by ignoring the average- case test logic and removing d, we recover the general adversarial attack algorithm. domain experts to (b), and ethicists and social sci- entists to (c). However, we recognize that such collaboration may not be feasible for every NLP system being tested. It is more realistic to expect ethicists to be involved when applying DOCTOR at the company and industry levels, and ethics-trained NLP practitioners to answer these questions within the development team. We provide a taxonomy of potential dimensions in Table 1 (Appendix). However, the key difference between an adversar- ial robustness mindset and a testing one is the lat- ter’s emphasis on identifying ways in which natural phenomena or ethical concerns can be operational- ized as reliability tests. This change in perspective opens up new avenues for interdisciplinary research that will allow researchers and practitioners to have more nuanced discussions about model reliability and can be used to design comprehensive reliability testing regimes. We describe such a framework for interdisciplinary collaboration next. Since it is likely unfeasible to test every possible di- mension, stakeholder advocates should be involved to ensure their values and interests are accurately represented and prioritized (Hagerty and Rubinov, 2019), while experts should ensure the dimensions identified can be feasibly tested. A similar ap- proach to that of community juries4 may be taken. 5 A Framework for Reliability Testing We introduce and then describe our general frame- work, DOCTOR, for testing the reliability of NLP systems. DOCTOR comprises six steps: 1. Define reliability requirements 2. Operationalize dimensions as distributions 3. Construct tests 2. Operationalize dimensions as distributions 3. Construct tests 4. Test system and report results 5. Observe deployed system’s behavior Next, we recommend using the same metrics for held-out, average-case, and worst-case perfor- mance for easy comparison. These often vary from task to task and are still a subject of active research (Novikova et al., 2017; Reiter, 2018; Kryscinski et al., 2019), hence the question of the right met- ric to use is beyond the scope of this paper. Fi- nally, ethicists, in consultation with the other afore- mentioned experts and stakeholders, will determine acceptable thresholds for worst-case performance. The system under test must perform above said thresholds when exposed to variation along those dimensions in order to pass. For worst-case perfor- mance, we recommend reporting thresholds as rel- ative differences (δ) between the average-case and worst-case performance. These questions may help in applying this step and deciding if specific NLP solutions should even exist (Leins et al., 2020): Next, we recommend using the same metrics for held-out, average-case, and worst-case perfor- mance for easy comparison. These often vary from task to task and are still a subject of active research (Novikova et al., 2017; Reiter, 2018; Kryscinski et al., 2019), hence the question of the right met- ric to use is beyond the scope of this paper. Fi- nally, ethicists, in consultation with the other afore- mentioned experts and stakeholders, will determine acceptable thresholds for worst-case performance. 6. Refine reliability requirements and tests Defining reliability requirements. Before any tests are constructed, experts and stakeholder advo- cates should work together to understand the demo- graphics and values of the communities the NLP system will interact with (Friedman and Hendry, 2019) and the system’s impact on their lives. The latter is also known as algorithmic risk assess- ment (Ada Lovelace Institute and DataKind UK, 2021). There are three critical questions to address: 1) Along what dimensions should the model be tested? 2) What metrics should be used to mea- sure system performance? 3) What are acceptable performance thresholds for each dimension? 4docs.microsoft.com/en-us/azure/.../community-jury 4 Adversarial Attacks as Reliability Tests We recommend using this question to evaluate the feasibility of operationalizing potential dimensions: “What is the system’s performance when exposed to variation along dimension d?”. For example, rather than simply “gender”, a better-defined di- mension would be “gender pronouns”. With this understanding, experts and policymakers can then create a set of reliability requirements, comprising the testing dimensions, performance metric(s), and passing thresholds. 5 A Framework for Reliability Testing Question 1 can be further broken down into: a) gen- eral linguistic phenomena, such as alternative spellings or code-mixing; b) task-specific quirks, e.g., an essay grading system should not use text length to predict score; c) sensitive attributes, such as gender, ethnicity, sexual orientation, age, or dis- ability status. This presents an opportunity for inter- disciplinary expert collaboration: Linguists are best equipped to contribute to discussions around (a), • Who will interact with the NLP system, in what context, and using which language varieties? • What are the distinguishing features of these va- rieties compared to those used for training? 4157 • What is the (short- and long-term) impact on the community’s most underrepresented members if the system performs more poorly for them? (e.g., Morpheus (Tan et al., 2020)) or model-based (e.g., BERT-Attack (Li et al., 2020a)). We recom- mend constructing tests that do not require access to the NLP model’s parameters (black-box assump- tion); this not only yields more system-agnostic tests, but also allows for (some) tests to be created independently from the system development team. If the black-box assumption proves limiting, the community can establish a standard set of items an NLP system should export for testing purposes, e.g., network gradients if the system uses a neural model. Regardless of assumption, keeping the reg- ulators’ test implementations separate and hidden from the system developers is critical for stake- holders and regulators to trust the results. This separation also reduces overfitting to the test suite. We note that our framework is general enough to be applied at various levels of organization: within the development team, within the company (com- pliance team, internal auditor), and within the in- dustry (self-regulation or independent regulator). However, we expect the exact set of dimensions, metrics and acceptable thresholds defined in Step 1 to vary depending on the reliability concerns of the actors at each level. For example, independent regulators will be most concerned with establishing minimum safety and fairness standards that all NLP systems used in their industries must meet, while compliance teams may wish to have stricter and more comprehensive standards for brand reasons. Developers can use DOCTOR to meet the other two levels of requirements and understand their system’s behaviour better with targeted testing. Testing systems. A possible model for test own- ership is to have independently implemented tests at the three levels of organization described above (team, company, industry). 5 A Framework for Reliability Testing At the development team level, reliability tests can be used to diag- nose weaknesses with the goal of improving the NLP system for a specific use case and set of target users. Compared to unconstrained adversarial ex- amples, contrasting worst-case examples that have been constrained along specific dimensions with non-worst-case examples will likely yield greater intuition into the model’s inner workings. Study- ing how modifications (to the architecture, training data and process) affect the system’s reliability on each dimension will also give engineers insight into the factors affecting system reliability. These tests should be executed and updated regularly during development, according to software engineering best practices such as Agile (Beck et al., 2001). Operationalizing dimensions. While the ab- stractness of dimensions allows people who are not NLP practitioners to participate in drafting the set of reliability requirements, there is no way to test NLP systems using fuzzy concepts. Therefore, every dimension the system is to be tested along must be operationalizable as a distribution from which perturbed examples can be sampled in order for NLP practitioners to realize them as tests. Since average-case tests attempt to estimate a sys- tem’s expected performance in its deployed envi- ronment, the availability of datasets that reflect real-world distributions is paramount to ensure that the tests themselves are unbiased. This is less of an issue for worst-case tests; the tests only needs to know which perturbations that are possible, but not how frequently they occur in the real world. Figur- ing out key dimensions for different classes of NLP tasks and exploring ways of operationalizing them as reliability tests are also promising directions for future research. Such research would help NLP practitioners and policymakers define reliability requirements that can be feasibly implemented. Red teams are company-internal teams tasked with finding security vulnerabilities in their developed software or systems. Brundage et al. (2020) pro- pose to apply the concept of red teaming to surface flaws in an AI system’s safety and security. In companies that maintain multiple NLP systems, we propose employing similar, specialized teams composed of NLP experts to build and maintain reliability tests that ensure their NLP systems ad- here to company-level reliability standards. These tests will likely be less task-/domain-specific than those developed by engineering teams due to their wider scope, while the reliability standards may be created and maintained by compliance teams or the red teams themselves. 6 From Concerns to Dimensions dards available for public scrutiny and ensuring their products meet them will enable companies to build trust with their users. To ensure all NLP systems meet the company’s reliability standards, these reliability tests should be executed as a part of regular internal audits (Raji et al., 2020), inves- tigative audits after incidents, and before major releases (especially if it is the system’s first release or if it received a major update). They may also be regularly executed on randomly chosen production systems and trigger an alert upon failure. We now illustrate how reliability concerns can be converted into concrete testing dimensions (Step 1) by considering the scenario of applying automated text scoring to short answers and essays from stu- dents in the multilingual population of Singapore. We study a second scenario in Appendix A. Au- tomated Text Scoring (ATS) systems are increas- ingly used to grade tests and essays (Markoff, 2013; Feathers, 2019). While they can provide instant feedback and help teachers and test agencies cope with large loads, studies have shown that they often exhibit demographic and language biases, such as scoring African- and Indian-American males lower on the GRE Argument task compared to human graders (Bridgeman et al., 2012; Ramineni and Williamson, 2018). Since the results of some tests will affect the futures of the test takers (Salaky, 2018), the scoring algorithms used must be suffi- ciently reliable. Hence, let us imagine that Singa- pore’s education ministry has decided to create a standard set of reliability requirements that all ATS systems used in education must adhere to. At the independent regulator level, reliability tests would likely be carried out during product certifi- cation (e.g., ANSI/ISO certification) and external audits. These industry-level reliability standards and tests may be developed in a similar manner to the company-level ones. However, we expect them to be more general and less comprehensive than the latter, analogous to minimum safety standards such as IEC 60335-1 (IEC, 2020). Naturally, high risk applications and NLP systems used in regu- lated industries should comply with more stringent requirements (European Commission, 2021). Linguistic landscape. A mix of language vari- eties are used in Singapore: a prestige English vari- ety, a colloquial English variety, three other official languages (Chinese, Malay, and Tamil), and a large number of other languages. English is the lingua franca, with fluency in the prestige variety corre- lating with socioeconomic status (Vaish and Tan, 2008). 5 A Framework for Reliability Testing Making these stan- Constructing tests. Next, average- and worst- case tests are constructed (Alg. 1). Average-case tests can be data-driven and could take the form of manually curated datasets or model-based per- turbation generation (e.g., PolyJuice (Wu et al., 2021)), while worst-case tests can be rule-based 4158 6 6 From Concerns to Dimensions models: Developers simply need to list the tested dimensions, metrics, and score on each dimension in the model card. Crucially, reliability tests can be used to highlight fairness issues in NLP sys- tems by including sensitive attributes for the target population, but it is paramount these requirements reflect local concerns rather than any prescriptivist perspective (Sambasivan et al., 2021). Dimension. We can generally categorize written tests into those that test for content correctness (e.g., essay questions in a history test), and those that test for language skills (e.g., proper use of grammar). While there are tests that simultane- ously assess both aspects, modern ATS systems often grade them separately (Ke and Ng, 2019). We treat each aspect as a separate test here. At the same time, the ability to conduct quantitative, targeted reliability testing along specifiable dimen- sions paves the way for reliability standards to be established, with varying levels of stringency and rigor for different use cases and industries. We envi- sion minimum safety and fairness standards being established for applications that are non-sensitive, not safety-critical, and used in unregulated indus- tries, analogous to standards for household appli- ances. Naturally, applications at greater risks (Li et al., 2020b) of causing harm upon failure should be held to stricter standards. Policymakers are start- ing to propose and implement regulations to en- force transparency and accountability in the use of AI systems. For example, the European Union’s General Data Protection Regulation grants data sub- jects the right to obtain “meaningful information about the logic involved” in automated decision systems (EU, 2016). The EU is developing AI- specific regulation (European Commission, 2020): e.g., requiring developers of high-risk AI systems to report their “capabilities and limitations, ... [and] the conditions under which they can be expected to function as intended”. In the U.S., a proposed bill of the state of Washington will require public agen- cies to report “any potential impacts of the auto- mated decision system on civil rights and liberties and potential disparate impacts on marginalized communities” before using automated decision sys- tems (Washington State Legislature, 2021). When grading students on content correctness, we would expect the ATS system to ignore linguistic variation and sensitive attributes as long as they do not affect the answer’s validity. 6 From Concerns to Dimensions A significant portion of the population does not speak English at home. Subjects other than languages are taught in English. Our proposed framework is also highly compatible with the use of model cards (Mitchell et al., 2019) for auditing and transparent reporting (Raji et al., 2020). In addition to performance on task-related metrics, model cards surface information and as- sumptions about a machine learning system and training process that may not be readily available otherwise. When a system has passed all tests and is ready to be deployed, its average- and worst-case performance on all tested dimensions can be in- cluded as an extra section on the accompanying model card. In addition, the perturbed examples generated during testing and their labels (x′, y′) can be stored for audit purposes or examined to ensure that the tests are performing as expected. Stakeholder impact. The key stakeholders af- fected by ATS systems would be students in schools and universities. The consequences of lower scores could be life-altering for the stu- dent who is unable to enroll in the major of their choice. At the population level, biases in an ATS system trained on normally sampled data would unfairly discriminate against already underrepre- sented groups. Additionally, biases against dis- fluent or ungrammatical text when they are not the tested attributes would result in discrimination against students with a lower socioeconomic status or for whom English is a second language. Observing and Refining requirements. It is crucial to regularly monitor the systems’ impact post-launch and add, update, or re-prioritize di- mensions and thresholds accordingly. Monitoring large-scale deployments can be done via commu- nity juries, in which stakeholders who will be likely impacted (or their advocates) give feedback on their pain points and raise concerns about potential neg- ative effects. Smaller teams without the resources to organize community juries can set up avenues (e.g., online forms) for affected stakeholders to give feedback, raise concerns, and seek remediation. Finally, NLP systems have also been known to be overly sensitive to alternative spellings (Belinkov and Bisk, 2018). When used to score subject tests, this could result in the ATS system unfairly penaliz- 4159 ing dyslexic students (Coleman et al., 2009). Since education is often credited with enabling social mobility,5 unfair grading may perpetuate systemic discrimination and increase social inequality. 5www.encyclopedia.com/.../education-and-mobility 6huggingface.co/models; github.com/ivylee/model-cards-and-datasheets; 6 From Concerns to Dimensions Hence, we would expect variation in these dimensions to have no ef- fect on scores: answer length, language/vocabulary simplicity, alternative spellings/misspellings of non-keywords, grammatical variation, syntactic variation (especially those resembling transfer from a first language), and proxies for sensitive attributes. On the other hand, the system should be able to differentiate proper answers from those aimed at gaming the test (Chin, 2020; Ding et al., 2020). When grading students on language skills, however, we would expect ATS systems to be only sensitive to the relevant skill. For example, when assessing grammar use, we would expect the system to be sensitive to grammatical errors (from the perspec- tive of the language variety the student is expected to use), but not to the other dimensions mentioned above (e.g., misspellings). Actors. Relevant experts include teachers of the subjects where the ATS systems will be deployed, linguists, and computer scientists. The stakeholders (students) may be represented by student unions (at the university level) or focus groups comprising a representative sample of the student population. One may note that language in the proposed regula- tion is intentionally vague. There are many ways to measure bias and fairness, depending on the type of model, context of use, and goal of the system. Today, companies developing AI systems employ the definitions they believe most reasonable (or perhaps easiest to implement), but regulation will need to be more specific for there to be meaningful compliance. DOCTOR’s requirement to explicitly define specific dimensions instead of a vague no- tion of reliability will help policymakers in this blog.einstein.ai/model-cards-for-ai-model-transparency 9 Conclusion Once language technologies leave the lab and start impacting real lives, concerns around safety, fair- ness, and accountability cease to be thought ex- periments. While it is clear that NLP can have a positive impact on our lives, from typing auto- completion to revitalizing endangered languages (Zhang et al., 2020a), it also has the potential to perpetuate harmful stereotypes (Bolukbasi et al., 2016; Sap et al., 2019), perform disproportionately poorly for underrepresented groups (Hern, 2017; Bridgeman et al., 2012), and even erase already marginalized communities (Bender et al., 2021). Trust in our tools stems from an assurance that stakeholders will remain unharmed, even in the worst-case scenario. In many mature industries, this takes the form of reliability standards. How- ever, for standards to be enacted and enforced, we must first operationalize “reliability”. Hence, we argue for the need for reliability testing (especially worst-case testing) in NLP by contextualizing it among existing work on promoting accountability and improving generalization beyond the training distribution. Next, we showed how adversarial at- tacks can be reframed as worst-case tests. Finally, we proposed a possible paradigm, DOCTOR, for how reliability concerns can be realized as quantita- tive tests, and discussed how this framework can be used at different levels of organization or industry. 8 Challenges and Future Directions While DOCTOR is a useful starting point to im- plement reliability testing for NLP systems, we observe key challenges to its widespread adoption. First, identifying and prioritizing the dimensions that can attest a system’s reliability and fairness. The former is relatively straightforward and can be achieved via collaboration with experts (e.g., as part of the U.S. NIST’s future AI standards (NIST, 2019)). The latter, however, is a question of values and power (Noble, 2018; Mohamed et al., 2020; Leins et al., 2020), and should be addressed via a code of ethics and ensuring that all stakeholders are adequately represented at the decision table. 7 Implications for Policy There is a mounting effort to increase accountabil- ity and transparency around the development and use of NLP systems to prevent them from ampli- fying societal biases. DOCTOR is highly comple- mentary to the model card approach increasingly adopted6 to surface oft hidden details about NLP 4160 regard, and can inform the ongoing development of national (NIST, 2019) and international standards7. evaluation metrics for natural language generation (Novikova et al., 2017; Reiter, 2018; Kryscinski et al., 2019): due to the tests’ synthetic nature they may not fully capture the nuances of reality. For example, if a test’s objective were to test an NLP system’s reliability when interacting with African American English (AAE) speakers, would it be possible to guarantee (in practice) that all gener- ated examples fall within the distribution of AAE texts? Potential research directions would be to design adversary generation techniques that can offer such guarantees or incorporate human feed- back (Nguyen et al., 2017; Kreutzer et al., 2018; Stiennon et al., 2020). While external algorithm audits are becoming pop- ular, testing remains a challenge since companies wishing to protect their intellectual property may be resistant to sharing their code (Johnson, 2021), and implementing custom tests for each system is unscalable. Our approach to reliability testing offers a potential solution to this conundrum by treating NLP systems as black boxes. If reliabil- ity tests become a legal requirement, regulatory authorities will be able to mandate independently conducted reliability tests for transparency. Such standards, combined with certification programs (e.g., IEEE’s Ethics Certification Program for Au- tonomous and Intelligent Systems8), will further incentivize the development of responsible NLP, as the companies purchasing NLP systems will insist on certified systems to protect them from both le- gal and brand risk. To avoid confusion, we expect certification to occur for individual NLP systems (e.g., an end-to-end question answering system for customer enquiries), rather than for general pur- pose language models that will be further trained to perform some specific NLP task. While con- crete standards and certification programs that can serve this purpose do not yet exist, we believe that they eventually will and hope our paper will inform their development. This multi-pronged approach can help to mitigate NLP’s potential harms while increasing public trust in language technology. 8standards.ieee.org/industry-connections/ecpais.html 7ethicsstandards.org/p7000 8 7ethicsstandards.org/p7000 8standards.ieee.org/industry-connections/ecpais.html Broader Impact Grenning, Jim Highsmith, Andrew Hunt, Ron Jeffries, Jon Kern, Brian Marick, Robert C. Martin, Steve Mel- lor, Ken Schwaber, Jeff Sutherland, and Dave Thomas. 2001. Manifesto for Agile Software Development. Much like how we expect to not be exposed to harmful electric shocks when using electrical ap- pliances, we should expect some minimum levels of safety and fairness for the NLP systems we in- teract with in our everyday lives. As mentioned in §1, §3, and §7, standards and regulations for AI systems are in the process of being developed for this purpose, especially for applications deemed “high-risk”, e.g., healthcare (European Commis- sion, 2020). Reliability testing, and our proposed framework, is one way to approach the problem of enacting enforceable standards and regulations. Yonatan Belinkov and Yonatan Bisk. 2018. Synthetic and natural noise both break neural machine translation. In 6th International Conference on Learning Represen- tations, Vancouver, BC, Canada. Emily M Bender and Batya Friedman. 2018. Data statements for natural language processing: Toward mitigating system bias and enabling better science. Transactions of the Association for Computational Lin- guistics, 6:587–604. Emily M. Bender, Timnit Gebru, Angelina McMillan- Major, and Shmargaret Shmitchell. 2021. On the dan- gers of stochastic parrots: Can language models be too big? In Proceedings of the Conference on Fairness, Accountability, and Transparency. However, the flip side of heavily regulating ev- ery single application of NLP is that it may slow down innovation. Therefore, it is important that the level of regulation for a particular application is proportionate to its potential for harm (Daten Ethik Kommission, 2019). Our framework can be adapted to different levels of risk by scaling down the implementation of some steps (e.g., the method and depth in which stakeholder consultation hap- pens or the comprehensiveness of the set of testing dimensions) for low-risk applications. Su Lin Blodgett, Solon Barocas, Hal Daumé III, and Hanna Wallach. 2020. Language (technology) is power: A critical survey of “bias” in NLP. In Proceed- ings of the 58th Annual Meeting of the Association for Computational Linguistics, pages 5454–5476, Online. Association for Computational Linguistics. Tolga Bolukbasi, Kai-Wei Chang, James Y Zou, Venkatesh Saligrama, and Adam T Kalai. 2016. Man is to computer programmer as woman is to home- maker? debiasing word embeddings. In D. D. Lee, M. Sugiyama, U. V. Luxburg, I. Guyon, and R. Gar- nett, editors, Advances in Neural Information Process- ing Systems 29, pages 4349–4357. Curran Associates, Inc. Acknowledgements Samson is supported by Salesforce and Singapore’s Economic Development Board under the Industrial Postgraduate Programme. Araz is supported by the NUS Centre for Trusted Internet and Community through project CTIC-RP-20-02. Second, our proposed method of reliability testing may suffer from similar issues plaguing automatic 4161 Broader Impact Finally, it is important to ensure that any tests, stan- dards, or regulations developed adequately repre- sents the needs of the most vulnerable stakeholders, instead of constructing them in a prescriptivist man- ner (Hagerty and Rubinov, 2019). Hence, DOC- TOR places a strong emphasis on involving stake- holder advocates and analyzing the impact of an application of NLP on the target community. Brent Bridgeman, Catherine Trapani, and Yigal Attali. 2012. Comparison of human and machine scoring of essays: Differences by gender, ethnicity, and country. Applied Measurement in Education, 25(1):27–40. Tom B. Brown, Benjamin Mann, Nick Ryder, Melanie Subbiah, Jared Kaplan, Prafulla Dhariwal, Arvind Neelakantan, Pranav Shyam, Girish Sastry, Amanda Askell, Sandhini Agarwal, Ariel Herbert- Voss, Gretchen Krueger, Tom Henighan, Rewon Child, Aditya Ramesh, Daniel M. Ziegler, Jeffrey Wu, Clemens Winter, Christopher Hesse, Mark Chen, Eric Sigler, Mateusz Litwin, Scott Gray, Benjamin Chess, Jack Clark, Christopher Berner, Sam McCandlish, Alec Radford, Ilya Sutskever, and Dario Amodei. 2020. Lan- guage models are few-shot learners. In Advances in Neural Information Processing Systems 33. Tom B. Brown, Benjamin Mann, Nick Ryder, Melanie Subbiah, Jared Kaplan, Prafulla Dhariwal, Arvind Neelakantan, Pranav Shyam, Girish Sastry, Amanda Askell, Sandhini Agarwal, Ariel Herbert- Voss, Gretchen Krueger, Tom Henighan, Rewon Child, Aditya Ramesh, Daniel M. Ziegler, Jeffrey Wu, Clemens Winter, Christopher Hesse, Mark Chen, Eric Sigler, Mateusz Litwin, Scott Gray, Benjamin Chess, Jack Clark, Christopher Berner, Sam McCandlish, Alec Radford, Ilya Sutskever, and Dario Amodei. 2020. Lan- guage models are few-shot learners. In Advances in Neural Information Processing Systems 33. Minhao Cheng, Wei Wei, and Cho-Jui Hsieh. 2019. References 116th U.S. Congress. 2019. Algorithmic Accountabil- ity Act of 2019. 116th U.S. Congress. 2019. Algorithmic Accountabil- ity Act of 2019. Ada Lovelace Institute and DataKind UK. 2021. Ex- amining the black box: Tools for assessing algorithmic systems. Technical report. Moustafa Alzantot, Yash Sharma, Ahmed Elgohary, Bo-Jhang Ho, Mani Srivastava, and Kai-Wei Chang. 2018. Generating natural language adversarial exam- ples. In Proceedings of the 2018 Conference on Empir- ical Methods in Natural Language Processing, pages 2890–2896, Brussels, Belgium. Association for Com- putational Linguistics. Miles Brundage, Shahar Avin, Jasmine Wang, Haydn Belfield, Gretchen Krueger, Gillian Hadfield, Heidy Khlaaf, Jingying Yang, Helen Toner, Ruth Fong, et al. 2020. Toward trustworthy AI development: mecha- nisms for supporting verifiable claims. arXiv preprint arXiv:2004.07213. Amnesty International. 2018. Toxic Twitter - triggers of violence and abuse against women on Twitter. Amnesty International. 2018. Toxic Twitter - triggers of violence and abuse against women on Twitter. California State Legislature. 2020. California Privacy Rights Act. California State Legislature. 2020. California Privacy Rights Act. Kent Beck, Mike Beedle, Arie van Bennekum, Alistair Cockburn, Ward Cunningham, Martin Fowler, James Kent Beck, Mike Beedle, Arie van Bennekum, Alistair Cockburn, Ward Cunningham, Martin Fowler, James Minhao Cheng, Wei Wei, and Cho-Jui Hsieh. 2019. 4162 Evaluating and enhancing the robustness of dialogue systems: A case study on a negotiation agent. In Pro- ceedings of the 2019 Conference of the North Ameri- can Chapter of the Association for Computational Lin- guistics: Human Language Technologies, Volume 1 (Long and Short Papers), pages 3325–3335, Minneapo- lis, Minnesota. Association for Computational Linguis- tics. Dheeru Dua, Yizhong Wang, Pradeep Dasigi, Gabriel Stanovsky, Sameer Singh, and Matt Gardner. 2019. DROP: A reading comprehension benchmark requiring discrete reasoning over paragraphs. In Proceedings of the 2019 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 1 (Long and Short Pa- pers), pages 2368–2378, Minneapolis, Minnesota. As- sociation for Computational Linguistics. Monica Chin. 2020. These students figured out their tests were graded by AI — and the easy way to cheat. The Verge. Michael Dunn. 2014. Gender determined dialect vari- ation. In The expression of gender, pages 39–68. De Gruyter. Katie Cohen, Fredrik Johansson, Lisa Kaati, and Jonas Clausen Mork. 2014. Detecting linguistic mark- ers for radical violence in social media. Terrorism and Political Violence, 26(1):246–256. Javid Ebrahimi, Anyi Rao, Daniel Lowd, and Dejing Dou. 2018. HotFlip: White-box adversarial examples for text classification. References In Proceedings of the 56th An- nual Meeting of the Association for Computational Lin- guistics (Volume 2: Short Papers), pages 31–36, Mel- bourne, Australia. Association for Computational Lin- guistics. Chris Coleman, Noël Gregg, Lisa McLain, and Leslie W Bellair. 2009. A comparison of spelling performance across young adults with and with- out dyslexia. Assessment for effective intervention, 34(2):94–105. Steffen Eger and Yannik Benz. 2020. From hero to zéroe: A benchmark of low-level adversarial attacks. In Proceedings of the 1st Conference of the Asia-Pacific Chapter of the Association for Computational Linguis- tics and the 10th International Joint Conference on Natural Language Processing, pages 786–803, Suzhou, China. Association for Computational Linguistics. Kate Crawford. 2017. The trouble with bias (keynote). Advances in Neural Information Processing Systems 30. Marina Danilevsky, Kun Qian, Ranit Aharonov, Yannis Katsis, Ban Kawas, and Prithviraj Sen. 2020. A survey of the state of explainable AI for natural language pro- cessing. In Proceedings of the 1st Conference of the Asia-Pacific Chapter of the Association for Computa- tional Linguistics and the 10th International Joint Con- ference on Natural Language Processing, pages 447– 459, Suzhou, China. Association for Computational Linguistics. EIU. 2020. Staying ahead of the curve: The busi- ness case for responsible AI. Technical report, The Economist Intelligence Unit. EU. 2016. General data protection regulation. European Commission. 2020. On artificial intelligence - a European approach to excellence and trust. Techni- cal report, European Commission. Daten Ethik Kommission. 2019. Opinion of the data ethics commission. Technical report, Data Ethics Com- mission of the Federal Government (Germany). European Commission. 2021. Proposal for a regulation laying down harmonised rules on artificial intelligence (artificial intelligence act). Technical report, European Commission. Thomas Davidson, Debasmita Bhattacharya, and Ing- mar Weber. 2019. Racial bias in hate speech and abu- sive language detection datasets. In Proceedings of the Third Workshop on Abusive Language Online, pages 25–35, Florence, Italy. Association for Computational Linguistics. FDA. 2021. Artificial intelligence/machine learning (ai/ml)-based software as a medical device (samd) ac- tion plan. Technical report, U.S. Food & Drug Admin- istration. Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. 2019. BERT: Pre-training of deep bidirectional transformers for language under- standing. In Proceedings of the 2019 Conference of the North American Chapter of the Association for Com- putational Linguistics: Human Language Technolo- gies, Volume 1 (Long and Short Papers), pages 4171– 4186, Minneapolis, Minnesota. Association for Com- putational Linguistics. Todd Feathers. 2019. References Flawed algorithms are grading millions of students’ essays. Vice. Adam Fisch, Alon Talmor, Robin Jia, Minjoon Seo, Eu- nsol Choi, and Danqi Chen. 2019. MRQA 2019 shared task: Evaluating generalization in reading comprehen- sion. In Proceedings of the 2nd Workshop on Machine Reading for Question Answering, pages 1–13, Hong Kong, China. Association for Computational Linguis- tics. Yuning Ding, Brian Riordan, Andrea Horbach, Aoife Cahill, and Torsten Zesch. 2020. Don’t take “nswvt- nvakgxpm” for an answer –the surprising vulnerabil- ity of automatic content scoring systems to adversarial input. In Proceedings of the 28th International Con- ference on Computational Linguistics, pages 882–892, Barcelona, Spain (Online). International Committee on Computational Linguistics. Batya Friedman and David G Hendry. 2019. Value Sen- sitive Design: Shaping Technology with Moral Imagi- nation. MIT Press. Bharath Ganesh. 2018. The ungovernability of digi- tal hate culture. Columbia Journal of International Af- fairs. 4163 Matt Gardner, Yoav Artzi, Victoria Basmov, Jonathan Berant, Ben Bogin, Sihao Chen, Pradeep Dasigi, Dheeru Dua, Yanai Elazar, Ananth Gottumukkala, Nitish Gupta, Hannaneh Hajishirzi, Gabriel Ilharco, Daniel Khashabi, Kevin Lin, Jiangming Liu, Nelson F. Liu, Phoebe Mulcaire, Qiang Ning, Sameer Singh, Noah A. Smith, Sanjay Subramanian, Reut Tsarfaty, Eric Wallace, Ally Zhang, and Ben Zhou. 2020. Eval- uating models’ local decision boundaries via contrast sets. In Findings of the Association for Computational Linguistics: EMNLP 2020, pages 1307–1323, Online. Association for Computational Linguistics. Dirk Hovy, Federico Bianchi, and Tommaso Fornaciari. 2020. “you sound just like your father” commercial machine translation systems include stylistic biases. In Proceedings of the 58th Annual Meeting of the Associ- ation for Computational Linguistics, pages 1686–1690, Online. Association for Computational Linguistics. Dirk Hovy and Shannon L Spruit. 2016. The social im- pact of natural language processing. In Proceedings of the 54th Annual Meeting of the Association for Com- putational Linguistics (Volume 2: Short Papers), pages 591–598. Ben Hutchinson, Vinodkumar Prabhakaran, Emily Denton, Kellie Webster, Yu Zhong, and Stephen De- nuyl. 2020. Social biases in NLP models as barriers for persons with disabilities. In Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics, pages 5491–5501, Online. Association for Computational Linguistics. Siddhant Garg and Goutham Ramakrishnan. 2020. BAE: BERT-based adversarial examples for text clas- sification. In Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing, Online. Association for Computational Linguistics. Timnit Gebru, Jamie Morgenstern, Briana Vecchione, Jennifer Wortman Vaughan, Hanna Wallach, Hal Daumé III, and Kate Crawford. 2018. References Datasheets for datasets. arXiv preprint arXiv:1803.09010. IEC. 2020. Household and similar electrical appliances – Safety – Part 1: General requirements. IEC 60335- 1:2020. Mor Geva, Yoav Goldberg, and Jonathan Berant. 2019. Are we modeling the task or the annotator? an investi- gation of annotator bias in natural language understand- ing datasets. In Proceedings of the 2019 Conference on Empirical Methods in Natural Language Processing and the 9th International Joint Conference on Natural Language Processing (EMNLP-IJCNLP), pages 1161– 1166, Hong Kong, China. Association for Computa- tional Linguistics. IEEE. 2017. ISO/IEC/IEEE International stan- dard - systems and software engineering–vocabulary. ISO/IEC/IEEE 24765:2017(E), pages 1–541. Mohit Iyyer, John Wieting, Kevin Gimpel, and Luke Zettlemoyer. 2018. Adversarial example generation with syntactically controlled paraphrase networks. In Proceedings of the 2018 Conference of the North Amer- ican Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 1 (Long Papers), pages 1875–1885, New Orleans, Louisiana. Association for Computational Linguistics. Karan Goel, Nazneen Rajani, Jesse Vig, Samson Tan, Jason Wu, Stephan Zheng, Caiming Xiong annd Mo- hit Bansal, and Christopher Ré. 2021. Robustness Gym: Unifying the NLP evaluation landscape. arXiv preprint arXiv:2101.04840. Robin Jia and Percy Liang. 2017. Adversarial ex- amples for evaluating reading comprehension systems. In Proceedings of the 2017 Conference on Empirical Methods in Natural Language Processing, pages 2021– 2031, Copenhagen, Denmark. Association for Compu- tational Linguistics. Ian J. Goodfellow, Jonathon Shlens, and Christian Szegedy. 2015. Explaining and harnessing adversarial examples. In 3rd International Conference on Learn- ing Representations, San Diego, California. Di Jin, Zhijing Jin, Joey Tianyi Zhou, and Peter Szolovits. 2020. Is BERT really robust? A strong baseline for natural language attack on text classifi- cation and entailment. In The Thirty-Fourth AAAI Conference on Artificial Intelligence, AAAI 2020, The Thirty-Second Innovative Applications of Artificial In- telligence Conference, IAAI 2020, The Tenth AAAI Sym- posium on Educational Advances in Artificial Intelli- gence, EAAI 2020, New York, NY, USA, February 7-12, 2020, pages 8018–8025. AAAI Press. Alexa Hagerty and Igor Rubinov. 2019. Global ai ethics: a review of the social impacts and ethical implications of artificial intelligence. arXiv preprint arXiv:1907.07892. Hany Hassan, Anthony Aue, Chang Chen, Vishal Chowdhary, Jonathan Clark, Christian Federmann, Xuedong Huang, Marcin Junczys-Dowmunt, William Lewis, Mu Li, et al. 2018. Achieving human parity on automatic chinese to english news translation. arXiv preprint arXiv:1803.05567. Khari Johnson. 2021. What algorithm auditing startups need to succeed. VentureBeat. References In Proceedings of the 2018 Conference of the North American Chapter of the Association for Computational Linguistics: Hu- man Language Technologies, Volume 3 (Industry Pa- pers), pages 92–105. Margaret Mitchell, Simone Wu, Andrew Zaldivar, Parker Barnes, Lucy Vasserman, Ben Hutchinson, Elena Spitzer, Inioluwa Deborah Raji, and Timnit Ge- bru. 2019. Model cards for model reporting. In Pro- ceedings of the Conference on Fairness, Accountability, and Transparency, pages 220–229. Shakir Mohamed, Marie-Therese Png, and William Isaac. 2020. Decolonial AI: Decolonial theory as so- ciotechnical foresight in artificial intelligence. Philoso- phy & Technology, 33(4):659–684. Wojciech Kryscinski, Nitish Shirish Keskar, Bryan Mc- Cann, Caiming Xiong, and Richard Socher. 2019. Neu- ral text summarization: A critical evaluation. In Pro- ceedings of the 2019 Conference on Empirical Methods in Natural Language Processing and the 9th Interna- tional Joint Conference on Natural Language Process- ing (EMNLP-IJCNLP), pages 540–551, Hong Kong, China. Association for Computational Linguistics. Stacy Nelson. 2003. Certification processes for safety- critical and mission-critical aerospace software. Tech- nical report, NASA Technical Reports Server. Khanh Nguyen, Hal Daumé III, and Jordan Boyd- Graber. 2017. Reinforcement learning for bandit neu- ral machine translation with simulated human feedback. In Proceedings of the 2017 Conference on Empirical Methods in Natural Language Processing, pages 1464– 1474. Zachary Laub. 2019. Hate speech on social media: Global comparisons. Council on Foreign Relations. Kobi Leins, Jey Han Lau, and Timothy Baldwin. 2020. Give me convenience and give her death: Who should decide what uses of NLP are appropriate, and on what basis? In Proceedings of the 58th Annual Meet- ing of the Association for Computational Linguistics, pages 2908–2913, Online. Association for Computa- tional Linguistics. Yixin Nie, Adina Williams, Emily Dinan, Mohit Bansal, Jason Weston, and Douwe Kiela. 2020. Adver- sarial NLI: A new benchmark for natural language un- derstanding. In Proceedings of the 58th Annual Meet- ing of the Association for Computational Linguistics, pages 4885–4901, Online. Association for Computa- tional Linguistics. Jinfeng Li, Shouling Ji, Tianyu Du, Bo Li, and Ting Wang. 2019. Textbugger: Generating adversarial text against real-world applications. In 26th Annual Net- work and Distributed System Security Symposium. NIST. 2019. U.S. leadership in AI: A plan for federal engagement in developing technical standards and re- lated tools. Technical report, National Institute of Stan- dards and Technology. Linyang Li, Ruotian Ma, Qipeng Guo, Xiangyang Xue, and Xipeng Qiu. 2020a. Bert-attack: Adversarial at- tack against BERT using BERT. References Dan Hendrycks, Xiaoyuan Liu, Eric Wallace, Adam Dziedzic, Rishabh Krishnan, and Dawn Song. 2020. Pretrained transformers improve out-of-distribution ro- bustness. In Proceedings of the 58th Annual Meet- ing of the Association for Computational Linguistics, pages 2744–2751, Online. Association for Computa- tional Linguistics. Dan Hendrycks, Xiaoyuan Liu, Eric Wallace, Adam Dziedzic, Rishabh Krishnan, and Dawn Song. 2020. Pretrained transformers improve out-of-distribution ro- bustness. In Proceedings of the 58th Annual Meet- ing of the Association for Computational Linguistics, pages 2744–2751, Online. Association for Computa- tional Linguistics. Divyansh Kaushik, Eduard Hovy, and Zachary Lipton. 2019. Learning the difference that makes a differ- ence with counterfactually-augmented data. In Inter- national Conference on Learning Representations. Divyansh Kaushik, Eduard Hovy, and Zachary Lipton. 2019. Learning the difference that makes a differ- ence with counterfactually-augmented data. In Inter- national Conference on Learning Representations. Zixuan Ke and Vincent Ng. 2019. Automated essay scoring: A survey of the state of the art. In Interna- tional Joint Conference on Artificial Intelligence. Inter- Zixuan Ke and Vincent Ng. 2019. Automated essay scoring: A survey of the state of the art. In Interna- tional Joint Conference on Artificial Intelligence. Inter- Alex Hern. 2017. Facebook translates ‘good morning’ into ‘attack them’, leading to arrest. The Guardian. Alex Hern. 2017. Facebook translates ‘good morning’ into ‘attack them’, leading to arrest. The Guardian. 4164 national Joint Conferences on Artificial Intelligence Or- ganization. Paul Michel, Xian Li, Graham Neubig, and Juan Pino. 2019. On evaluation of adversarial perturbations for sequence-to-sequence models. In Proceedings of the 2019 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 1 (Long and Short Pa- pers), pages 3103–3114, Minneapolis, Minnesota. As- sociation for Computational Linguistics. Daniel Khashabi, Tushar Khot, and Ashish Sabharwal. 2020. More bang for your buck: Natural perturba- tion for robust question answering. In Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP), pages 163–170, On- line. Association for Computational Linguistics. John Miller, Karl Krauth, Benjamin Recht, and Lud- wig Schmidt. 2020. The effect of natural distribution shift on question answering models. arXiv preprint arXiv:2004.14444. Kate Klonick. 2018. The new governors: The people, rules, and processes governing online speech. Harvard Law Review, 131(6):1598. Julia Kreutzer, Shahram Khadivi, Evgeny Matusov, and Stefan Riezler. 2018. Can neural machine transla- tion be improved with user feedback? References In Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing, Online. Association for Compu- tational Linguistics. Safiya Umoja Noble. 2018. Algorithms of oppression: How search engines reinforce racism. NYU Press. Jekaterina Novikova, Ondˇrej Dušek, Amanda Cer- cas Curry, and Verena Rieser. 2017. Why we need new evaluation metrics for NLG. In Proceedings of the 2017 Conference on Empirical Methods in Natural Language Processing, pages 2241–2252, Copenhagen, Denmark. Association for Computational Linguistics. Yanwei Li, Araz Taeihagh, Martin de Jong, and An- dreas Klinke. 2020b. Toward a commonly shared pub- lic policy perspective for analyzing risk coping strate- gies. Risk Analysis. John Markoff. 2013. Essay-grading software offers professors a break. The New York Times. Cathy O’Neil. 2016. Weapons of math destruc- tion: How big data increases inequality and threatens democracy. Crown. Alexandria Marsters. 2019. When Hate Speech Leads to Hateful Actions: A Corpus and Discourse Ana- lytic Approach to Linguistic Threat Assessment of Hate Speech. Ph.D. thesis, Georgetown University, Wash- ington, D.C. Partnership on AI. 2019. About ML. Technical report, Partnership on AI. 4165 Barbara Plank. 2016. What to do about non-standard (or non-canonical) language in NLP. Proceedings of the 13th Conference on Natural Language Processing (KONVENS 2016). Nithya Sambasivan, Erin Arnesen, Ben Hutchinson, Tulsee Doshi, and Vinodkumar Prabhakaran. 2021. Re- imagining algorithmic fairness in india and beyond. In Proceedings of the 2021 Conference on Fairness, Ac- countability, and Transparency. Megha Rajagopalan, Lam Thuy Vo, and Aung Naing Soe. 2018. How Facebook failed the Rohingya in Myanmar. BuzzFeed News. Maarten Sap, Dallas Card, Saadia Gabriel, Yejin Choi, and Noah A. Smith. 2019. The risk of racial bias in hate speech detection. In Proceedings of the 57th An- nual Meeting of the Association for Computational Lin- guistics, pages 1668–1678, Florence, Italy. Association for Computational Linguistics. Inioluwa Deborah Raji, Andrew Smart, Rebecca N White, Margaret Mitchell, Timnit Gebru, Ben Hutchin- son, Jamila Smith-Loud, Daniel Theron, and Parker Barnes. 2020. Closing the AI accountability gap: Defining an end-to-end framework for internal algorith- mic auditing. In Proceedings of the 2020 Conference on Fairness, Accountability, and Transparency, pages 33–44. Suchi Saria and Adarsh Subbaswamy. 2019. Safe and reliable machine learning (tutorial). ACM Conference on Fairness, Accountability, and Transparency. Deven Santosh Shah, H. Andrew Schwartz, and Dirk Hovy. 2020. Predictive biases in natural language processing models: A conceptual framework and overview. References In Proceedings of the 58th Annual Meet- ing of the Association for Computational Linguistics, pages 5248–5264, Online. Association for Computa- tional Linguistics. Bogdana Rakova, Jingying Yang, Henriette Cramer, and Rumman Chowdhury. 2020. Where responsible ai meets reality: Practitioner perspectives on enablers for shifting organizational practices. arXiv preprint arXiv:2006.12358. Chaitanya Ramineni and David Williamson. 2018. Un- derstanding mean score differences between the e- rater® automated scoring engine and humans for de- mographically based groups in the GRE® general test. ETS Research Report Series, 2018(1):1–31. Andrew Smith. 2020. Using artificial intelligence and algorithms. Anders Søgaard, Sebastian Ebert, Jasmijn Bastings, and Katja Filippova. 2021. We need to talk about ran- dom splits. In Proceedings of the 16th Conference of the European Chapter of the Association for Compu- tational Linguistics: Main Volume, pages 1823–1832, Online. Association for Computational Linguistics. Ehud Reiter. 2018. A structured review of the validity of BLEU. Computational Linguistics, 44(3):393–401. Shuhuai Ren, Yihe Deng, Kun He, and Wanxiang Che. 2019. Generating natural language adversarial exam- ples through probability weighted word saliency. In Proceedings of the 57th Annual Meeting of the Associa- tion for Computational Linguistics, pages 1085–1097. Nisan Stiennon, Long Ouyang, Jeff Wu, Daniel M Ziegler, Ryan Lowe, Chelsea Voss, Alec Radford, Dario Amodei, and Paul Christiano. 2020. Learning to summarize from human feedback. arXiv preprint arXiv:2009.01325. Marco Tulio Ribeiro, Sameer Singh, and Carlos Guestrin. 2016. "why should i trust you?": Explain- ing the predictions of any classifier. In Proceedings of the 22nd ACM SIGKDD International Conference on Knowledge Discovery and Data Mining, KDD ’16, page 1135–1144, New York, NY, USA. Association for Computing Machinery. Samson Tan and Shafiq Joty. 2021. Code-Mixing on Sesame Street: Dawn of the adversarial polyglots. In Proceedings of the 2021 Conference of the North Amer- ican Chapter of the Association for Computational Lin- guistics: Human Language Technologies, Online. As- sociation for Computational Linguistics. Marco Tulio Ribeiro, Sameer Singh, and Carlos Guestrin. 2018. Semantically equivalent adversarial rules for debugging NLP models. In Proceedings of the 56th Annual Meeting of the Association for Com- putational Linguistics (Volume 1: Long Papers), pages 856–865, Melbourne, Australia. Association for Com- putational Linguistics. Samson Tan, Shafiq Joty, Min-Yen Kan, and Richard Socher. 2020. It’s morphin’ time! Combating linguis- tic discrimination with inflectional perturbations. In Proceedings of the 58th Annual Meeting of the Associ- ation for Computational Linguistics, pages 2920–2935, Online. Association for Computational Linguistics. References Marco Tulio Ribeiro, Tongshuang Wu, Carlos Guestrin, and Sameer Singh. 2020. Beyond accuracy: Behav- ioral testing of NLP models with CheckList. In Pro- ceedings of the 58th Annual Meeting of the Association for Computational Linguistics, pages 4902–4912, On- line. Association for Computational Linguistics. Marco Tulio Ribeiro, Tongshuang Wu, Carlos Guestrin, and Sameer Singh. 2020. Beyond accuracy: Behav- ioral testing of NLP models with CheckList. In Pro- ceedings of the 58th Annual Meeting of the Association for Computational Linguistics, pages 4902–4912, On- line. Association for Computational Linguistics. Deborah Tannen. 1991. You just don’t understand: Women and men in conversation. Ballantine books New York. Deborah Tannen et al. 2005. Conversational style: An- alyzing talk among friends. Oxford University Press. Anne-Laure Rousseau, Clément Baudelaire, and Kevin Riera. 2020. Doctor GPT-3: hype or reality? Nabla Technologies Blog. Viniti Vaish and Teck Kiang Tan. 2008. Language and social class: Linguistic capital in Singapore. In Annual Meeting of the American Educational Research Associ- ation. American Educational Research Association. Kristin Salaky. 2018. What standardized tests look like in 10 places around the world. INSIDER. 4166 Claudia Wagner, David Garcia, Mohsen Jadidi, and Markus Strohmaier. 2015. It’s a man’s Wikipedia? As- sessing gender inequality in an online encyclopedia. In Proceedings of the International AAAI Conference on Web and Social Media, volume 9. Wei Emma Zhang, Quan Z. Sheng, Ahoud Alhazmi, and Chenliang Li. 2020b. Adversarial attacks on deep- learning models in natural language processing: A sur- vey. ACM Transactions on Intelligent Systems and Technology, 11(3). Yuan Zhang, Jason Baldridge, and Luheng He. 2019b. PAWS: Paraphrase adversaries from word scrambling. In Proceedings of the 2019 Conference of the North American Chapter of the Association for Computa- tional Linguistics: Human Language Technologies, Volume 1 (Long and Short Papers), pages 1298–1308, Minneapolis, Minnesota. Association for Computa- tional Linguistics. Lily Wakefield. 2020. Queer people are being forced off social media by trolling and online abuse, searingly obvious report confirms. PinkNews. Eric Wallace, Shi Feng, Nikhil Kandpal, Matt Gardner, and Sameer Singh. 2019. Universal adversarial triggers for attacking and analyzing NLP. In Proceedings of the 2019 Conference on Empirical Methods in Natural Language Processing and the 9th International Joint Conference on Natural Language Processing (EMNLP- IJCNLP), pages 2153–2162, Hong Kong, China. Asso- ciation for Computational Linguistics. Zeerak Waseem, Smarika Lulz, Joachim Bingel, and Is- abelle Augenstein. 2021. Disembodied machine learn- ing: On the illusion of objectivity in NLP. arXiv preprint arXiv:2101.11974. A Testing Dimensions: Detecting Violent Content on Social Media In this second case study, we apply DOCTOR for measuring the reliability of a violent content de- tection system for English social media posts. Al- though we limit this discussion to the U.S., this is a growing global problem (Laub, 2019) that can lead to deadly outcomes (Rajagopalan et al., 2018). In this hypothetical use case, the NLP system may au- tomatically remove violent content or alert content moderators to potential violations of the social me- dia company’s acceptable use policy. Moderators can decide if specific content should be removed, and if necessary, notify law enforcement to avert pending violence (e.g., threats against individuals, planned violent events). As a result of the 1996 Communications Decency Act9, social media plat- forms have broad latitude (Klonick, 2018) to de- velop their own policies for acceptable content and how they handle it. In this scenario, the compliance officer of the company developing the system is re- sponsible for making sure it does not discriminate against specific user demographics. Dimensions. There are two tasks under consider- ation here: identifying violent content and identi- fying Hunters who “truly intend to use lethal vio- lence” (Marsters, 2019). In the first task, the sys- tem is looking for content that negatively targets a socially defined group. Additionally, the content includes not only hate speech (e.g., profanity, epi- thets, vulgarity) but also content that incites others to hatred or violence. Since content written in AAE has been shown to be flagged as toxic more often (Sap et al., 2019; Davidson et al., 2019), we must ensure that the system is reliable when encounter- ing dialectal variation. Additionally, due to the casual environment of social media, multilingual speakers often code-switch and code-mix. Hence, we expect variation in these dimensions to have no effect on the system’s predictions: alternative spellings, morphosyntactic variation, word choice, code-mixing, idioms, and references to and mani- festations of sensitive attributes and their proxies. However, we must expect the system to be sensitive to in-group and out-group usage of reclaimed slurs so that the in-group usage does not result in a flag while out-group usage result in flagged posts. Research has shown that hate speech can lead to hateful actions (Marsters, 2019). In many cases, individuals posted their intents online prior to com- mitting violence (Cohen et al., 2014). 9fcc.gov/general/telecommunications-act-1996 Appendix different Latinx (Hispanic) vernacular Englishes. different Latinx (Hispanic) vernacular Englishes ( p ) g Stakeholder Impact. The key stakeholders that will be impacted are those most often facing violent threats online: minorities, women, immigrants, and the LGBTQ community (Amnesty International, 2018; Ganesh, 2018; Davidson et al., 2019; Wake- field, 2020). Additionally, anyone that posts con- tent on the social media site is a stakeholder. Un- fortunately, the very communities that are often the target of violent posts are also often wrongly flagged as posting toxic content themselves due to racial biases present in the training data (Sap et al., 2019; Davidson et al., 2019). Given the risk of harm to victims if the system misses violent posts from hunters or misidentifies legitimate content as violent and notifies law enforcement, it is critical the right balance of false positives and false nega- tives is achieved in flagging content. Stakeholder Impact. The key stakeholders that will be impacted are those most often facing violent threats online: minorities, women, immigrants, and the LGBTQ community (Amnesty International, 2018; Ganesh, 2018; Davidson et al., 2019; Wake- field, 2020). Additionally, anyone that posts con- tent on the social media site is a stakeholder. Un- fortunately, the very communities that are often the target of violent posts are also often wrongly flagged as posting toxic content themselves due to racial biases present in the training data (Sap et al., 2019; Davidson et al., 2019). Given the risk of harm to victims if the system misses violent posts from hunters or misidentifies legitimate content as violent and notifies law enforcement, it is critical the right balance of false positives and false nega- tives is achieved in flagging content. References Washington State Legislature. 2021. Senate bill SB 5116. Gerhard Widmer and Miroslav Kubat. 1996. Learning in the presence of concept drift and hidden contexts. Machine Learning, 23:69–101. Chris Wilkinson, Jonathan Lynch, Raj Bharadwaj, and Kurt Woodham. 2016. Verification of adaptive sys- tems. Technical report, Federal Aviation Administra- tion William J. Hughes Technical Center. Tongshuang Wu, Marco Tulio Ribeiro, Jeffrey Heer, and Daniel S Weld. 2021. Polyjuice: Automated, general-purpose counterfactual generation. arXiv preprint arXiv:2101.00288. Adams Wei Yu, David Dohan, Quoc Le, Thang Luong, Rui Zhao, and Kai Chen. 2018. Fast and accurate read- ing comprehension by combining self-attention and convolution. In International Conference on Learning Representations. Yuan Zang, Fanchao Qi, Chenghao Yang, Zhiyuan Liu, Meng Zhang, Qun Liu, and Maosong Sun. 2020. Word- level textual adversarial attacking as combinatorial op- timization. In Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics, pages 6066–6080. Huangzhao Zhang, Hao Zhou, Ning Miao, and Lei Li. 2019a. Generating fluent adversarial examples for nat- ural languages. In Proceedings of the 57th Annual Meeting of the Association for Computational Linguis- tics, pages 5564–5569, Florence, Italy. Association for Computational Linguistics. Shiyue Zhang, Benjamin Frey, and Mohit Bansal. 2020a. ChrEn: Cherokee-English machine translation for endangered language revitalization. In Proceedings of the 2020 Conference on Empirical Methods in Nat- ural Language Processing (EMNLP), pages 577–595, Online. Association for Computational Linguistics. 4167 A Testing Dimensions: Detecting Violent Content on Social Media When iden- tifying content to remove and especially when in- volving law enforcement, it is important to distin- guish between “Hunters" — those who act — and “Howlers" — those who do not (Marsters, 2019). This is to avoid wrongly detaining individuals who have no intention of committing violence, even if their words are indefensible. Between these ex- tremes, posters may harass, stalk, dox, or otherwise abuse victims from a distance, therefore it is still necessary to flag, remove, and potentially track or document violent content. Linguistic landscape. We focus solely on En- glish speakers, but we acknowledge that the actual linguistic landscape is much more complex (over 350 languages). Posters on social media may speak English as their first language or as a second lan- guage and they often code-switch/-mix. Standard American English is used for business purposes in the U.S. but there are other frequently used lan- guage varieties including African American En- glish (AAE), Cajun Vernacular English, and three When identifying hunters, we may expect the sys- tem to be sensitive to uses of first person pronouns, certainty adverbs, negative evaluative adjectives, and modifiers (Marsters, 2019). However, in or- der to avoid unfairly penalizing vernacular English speakers we should expect the system’s predictions to be equally unaffected by variation in the dimen- sions listed for the first task. 4168 Orthography Hyphenation Capitalization Punctuation Reduplication of letters Emojis/emoticons Homonyms Disemvoweling (Eger and Benz, 2020) Homophones (e.g., accept vs. except) (Eger and Benz, 2020) Accidental misspellings (Belinkov and Bisk, 2018) Intentional alternative spellings (e.g., Yas, thru, startin) Open compound concatenation (e.g., couch potato/couchpotato) Dialectal differences (e.g., favor vs. favour) (Ribeiro et al., 2018) Mixing writing scripts (Tan and Joty, 2021) Transliteration Morphology Grammatical gender shifts Grammatical category (Tan et al., 2020) Dialectal differences (Tan et al., 2020) Linguistic Clitics Phenomena Lexicon Dialectal variation (e.g., fries vs. chips) Synonyms/Sememes (Zang et al., 2020) Vocabulary simplicity/complexity Cross-lingual synonyms (Tan and Joty, 2021) Loanwords Semantics Idioms (e.g., finer than frog hair) Syntax Matching number and tense Word/phrase order (especially for languages without strict word ordering) Prepositional variation (e.g., stand on line vs. A Testing Dimensions: Detecting Violent Content on Social Media stand in line) Syntactic variation (Iyyer et al., 2018) Sentence simplicity/complexity Code-mixing (Tan and Joty, 2021) Register (e.g., formality) Discourse Conversational style (involvement/considerateness) (Tannen et al., 2005) & Discourse markers / connector words Pragmatics Cross-cultural differences Code-switching Sensitive Attributes Gender Identity Gender pronouns Names Reclaimed slurs Genderlects (Tannen, 1991; Dunn, 2014) Race Names Reclaimed slurs Race-aligned language varieties Age Age/generation-aligned language styles (Hovy et al., 2020) Religion Names Reclaimed slurs Sexual Orientation Reclaimed slurs Disability status Associated adjectives (Hutchinson et al., 2020) Place of origin Location names (e.g., cities, countries) Figures of speech Proxies Geographic locations (for ethnicity, socioeconomic status) Malicious Attacks Black-box Rule-based (Alzantot et al., 2018; Jin et al., 2020) Model-based (Garg and Ramakrishnan, 2020; Li et al., 2020a) Gradient-based HotFlip (Ebrahimi et al., 2018), Universal Triggers (Wallace et al., 2019) Policy-based Adversarial negotiation agent (Cheng et al., 2019) Table 1: Taxonomy of possible dimensions with references to linguistics literature and existing adversarial attacks that could be used as worst-case tests. Linguists are best equipped to decide which linguistic phenomena are high Table 1: Taxonomy of possible dimensions with references to linguistics literature and existing adversarial attacks that could be used as worst-case tests. Linguists are best equipped to decide which linguistic phenomena are high priority for each use case, ethicists for sensitive attributes, and NLP practitioners for malicious attacks. Table 1: Taxonomy of possible dimensions with references to linguistics literature and existing adversarial attacks that could be used as worst-case tests. Linguists are best equipped to decide which linguistic phenomena are high priority for each use case, ethicists for sensitive attributes, and NLP practitioners for malicious attacks. 4169
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Do Reproductive Factors Influence T, N, and M Classes of Ductal and Lobular Breast Cancers? A Nation-Wide Follow-Up Study
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Citation for published version (APA): Mousavi, S. M., Försti, A., Sundquist, K., & Hemminki, K. (2013). Do Reproductive Factors Influence T, N, and M Classes of Ductal and Lobular Breast Cancers? A Nation-Wide Follow-Up Study. PLoS ONE, 8(5), Article e58867. https://doi.org/10.1371/journal.pone.0058867 Do Reproductive Factors Influence T, N, and M Classes of Ductal and Lobular Breast Cancers? A Nation-Wide Follow-Up Study Mousavi, Seyed Mohsen; Försti, Asta; Sundquist, Kristina; Hemminki, Kari Published in: PLoS ONE DOI: 10.1371/journal.pone.0058867 2013 Link to publication Citation for published version (APA): Mousavi, S. M., Försti, A., Sundquist, K., & Hemminki, K. (2013). Do Reproductive Factors Influence T, N, and M Classes of Ductal and Lobular Breast Cancers? A Nation-Wide Follow-Up Study. PLoS ONE, 8(5), Article e58867. https://doi.org/10.1371/journal.pone.0058867 T t l b f th Do Reproductive Factors Influence T, N, and M Classes of Ductal and Lobular Breast Cancers? A Nation-Wide Follow-Up Study Link to publication Citation for published version (APA): Mousavi, S. M., Försti, A., Sundquist, K., & Hemminki, K. (2013). Do Reproductive Factors Influence T, N, and M Classes of Ductal and Lobular Breast Cancers? A Nation-Wide Follow-Up Study. PLoS ONE, 8(5), Article e58867. https://doi.org/10.1371/journal.pone.0058867 Total number of authors: 4 Abstract The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Funding: This study was supported by the Deutsche Krebshilfe, the Swedish Council for Working Life and Social Resear The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manu Competing Interests: The authors have declared that no competing interests exist. * E-mail: K.Hemminki@dkfz.de Abstract Backgrounds: The clinical tumor-node-metastasis (T, N and M) classes of breast cancers provide important prognostic information. However, the possible association of TNM classes with reproductive factors has remained largely unexplored. Because every woman has a reproductive history, implications to outcome prediction are potentially significant. Methods: During the study period from 2002 through 2008, 5,614 pre- and 27,310 postmenopausal patients were identified in the Swedish Family-Cancer Database. Ordinal logistic regression analysis was used to estimate odds ratios (ORs) for TNM classes of breast cancers by histology. The reproductive variables were parity, age at first and last childbirth and time interval between first and last childbirth. Results: Among postmenopausal patients, the ORs for high-T class (T2–T4) (tumor size $2 cm) and metastasis were decreased by parity. A late age at first and last childbirth associated with high-T class and the effects were higher for lobular (OR for late age at first childbirth = 2.85) than ductal carcinoma. Overall, long time interval between first and last childbirth was related to high-T class and metastasis. However, a short time interval between first and last childbirth in patients with late age at first or last childbirth increased the risk of metastasis. Late age at last childbirth was associated with increased occurrence of lobular carcinoma in situ. Among premenopausal ductal carcinoma patients, nulliparity and early age at first childbirth were associated with high-T class. Conclusions: Increasing parity was protective against high-T class and metastasis; late ages at first and last childbirth were risk factors for high-T class in postmenopausal breast cancers. The current decline in parity and delayed age at first childbirth in many countries may negatively influence prognosis of breast cancer. ation: Mousavi SM, Fo¨rsti A, Sundquist K, Hemminki K (2013) Do Reproductive Factors Influence T, N, and M Classes of Ductal and Lob tion-Wide Follow-Up Study. PLoS ONE 8(5): e58867. doi:10.1371/journal.pone.0058867 Editor: Tatjana Adamovic, Karolinska Institutet, Sweden Received November 19, 2012; Accepted February 7, 2013; Published May 29, 2013 Copyright:  2013 Mousavi et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This study was supported by the Deutsche Krebshilfe, the Swedish Council for Working Life and Social Research, and EU FP7/2007–2013 grant 260715. Do Reproductive Factors Influence T, N, and M Classes of Ductal and Lobular Breast Cancers? A Nation-Wide Follow-Up Study Seyed Mohsen Mousavi1, Asta Fo¨ rsti1,2, Kristina Sundquist2, Kari Hemminki1,2* 1 Division of Molecular Genetic Epidemiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2 Center for Primary Health Care Research, Lund University/ Region Ska˚ne, Malmo¨, Sweden Seyed Mohsen Mousavi1, Asta Fo¨ rsti1,2, Kristina Sundquist2, Kari Hemminki1,2* y q 1 Division of Molecular Genetic Epidemiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2 Center for Primary Health Care Research, Lund University/ Region Ska˚ne, Malmo¨, Sweden General rights U l th General rights Unless other specific re-use rights are stated the following general rights apply: Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. p g g g g pp y Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. g q g • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal Read more about Creative commons licenses: https://creativecommons.org/licenses/ Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. LUND UNIVERSITY PO Box 117 221 00 Lund +46 46-222 00 00 Results We identified 27,310 postmenopausal and 5,614 premenopaus- al breast cancer patients in the database. The histological type of breast cancer among postmenopausal patients was ductal in 68.5% of patients and lobular in 14.8% of patients, while premenopausal carcinomas were 77.1% ductal and 10.1% lobular. Our data included 10,794 T1, 13,767 N0 and 15,186 M0 cases of postmenopausal breast cancer (Table 1). Parity had no significant influence on carcinoma in situ. For invasive cancer, we calculated ORs for any T class separately. The results were very similar for any of them. Therefore, to catch the maximum number of cases for each group, we combined T2–T4. The OR decreased for higher T classes (T2–T4) among patients with two (0.82) or three (0.83) children compared to patients with one child. Multiparity was associated with a decreased risk of distant metastases (ORs ranging from 0.65 to 0.70). For invasive breast cancer, increasing age at first and last childbirth above 30 years were associated with a higher T class; the OR was 1.84 and 1.45 for those with an age at first and last childbirth over 39 years, respectively. Similarly, a time interval between first and last childbirth $10 years associated with an increasing T. Patients with an age at last childbirth $40 years were at an increased risk of lymph node involvement (1.22), while those with a time interval between first and last childbirth $5 years had a risk of distant metastases (1.40 for time interval between first and last childbirth 5–9 years). Risk of metastasis was also increased for cases with an age at first childbirth #19 years (1.34). Tumor size and local growth (T), regional lymph node involvement (N) and the presence of metastasis (M) according to the TNM classification system published by the American Joint Committee on Cancer have been available in the FCD since 2002 [6,29]. The basis for TNM classification in the FCD was clinical or pathological findings [28]. Numbers or letters after T, N and M provide more details about the classification. The numbers 0 through 4 indicate increasing severity. Breast cancer patients in native Swedish women from 2002 to 2008 were obtained from the FCD. Parity (0, 1, 2, 3 and $4), age at first and last childbirth (#19, 20–29, 30–39 and $40), and time interval between first and last childbirth (1–4, 5–9 and $10) were obtained from the FCD. Introduction and rapid proliferation of breast tissue during pregnancy and lactation play a major role [9,15–17]. Demographic changes over recent decades in developed countries and even among educated women in developing countries have modified reproductive patterns towards delayed childbearing and declining parity [1–4]. Reproductive factors are strongly associated with the risk of breast cancer and, unfortu- nately, both delayed childbearing and low parity increase the risk of breast cancer [5]. In fact, in developed countries these two reproductive parameters may explain as much as 30 to 40% of breast cancer etiology [6]. Many studies have also shown that reproductive factors differentially influence breast cancer histology [7,8]. For example, multiparity is known to decrease the risk of ductal and lobular carcinomas, while late age at first childbirth increases the risk [7–11]. The influence of age at last childbirth and birth interval remains unclear [12–14]. The underlying mechanisms are not well known but, it is widely believed that hormonal and other physiological changes in the mammary gland In developed countries, breast cancer is mainly a postmeno- pausal disease. The effects of reproductive factors on histology of breast cancer vary according to the menopausal status [8,18]. Among postmenopausal women, the effects of reproductive factors are more strongly associated with invasive ductal than lobular carcinoma [19]. However, for in situ breast cancer the reverse may be true [20,21]. Among premenopausal women, reproductive risk factors may be more strongly associated with in situ than invasive cancers [18,22]. Only a few previous studies have examined the effect of reproductive factors on the stage or grade of histology-specific breast cancer [12,20,21]. These suggest that nulliparity, late age at first childbirth, and the first two years after pregnancy are associated with unfavorable clinical data. To our knowledge, no previous study has analyzed the association of reproductive factors with tumor-node-metastasis (T, N and M) classes of breast cancer 1 PLOS ONE | www.plosone.org May 2013 | Volume 8 | Issue 5 | e58867 Reproductive Factors and TNM in Breast Cancer analysis. A P-value of less than 0.05 was considered statistically significant. which provide important prognostic information [23–25]. We explore here the association of parity, age at first and last childbirth, and time interval between first and last childbirth with the TNM classes of ductal and lobular carcinomas, the most common histological subtypes [5]. Both pre- and postmenopausal breast cancers were included from the Swedish Cancer Registry from 2002 through 2008. Patients and Methods We used the 2010 update of the Swedish Family-Cancer Database (FCD), which contains population-based data from the Swedish Cancer Registry, multigenerational registries, national censuses and death notifications [26,27]. This database contains information on people born in Sweden since 1932 and their biological parents. Native Swedish women were defined as those who, along with their parents, were born in Sweden. Introduction Our study population comprised 23,045 ductal, 4,611 lobular, 1,047 tubular and 728 mucinous carcinoma patients. The analyses of the last two histologies are not presented in this report because of the small numbers of cases in the TNM classes for menopausal status and any reproductive factors. As there are correlations between the variables age at first and last childbirth and time interval between first and last childbirth, we stratified age at first and last childbirth by time interval between first and last childbirth. Alternatively, we examined the effect of parity and the time interval between first and last childbirth by adding the age at first or last childbirth to the adjustment; however, because of the small numbers of premenopausal breast cancer cases in any subclasses, this analysis was only applied to postmenopausal cases. Ethics Statement Following the start of cancer registration in 1958, data on cancers in the FCD had a 4-digit diagnostic code according to the seventh revision of the International Classification of Disease (ICD). The codes for breast cancer were 170.1 and 170.2. Since 1993, ICD-O-2/ICD with histopathological data according to the Systematized Nomenclature of Medicine (SNOMED) has been used. This coding system gives a detailed tumor histology- topology. We analyzed ductal (SNOMED = 8500 and 8501), lobular (8520), tubular (8211) and mucinous (8480) carcinomas. Nonspecific adenocarcinoma (8140) was not included in our analysis (N = 2,493). All breast cancer cases (100%) registered in the Cancer Registry were histologically verified [28]. The Lund regional Ethics Committee approved the study protocol. The corresponding author had full access to the FCD and had final responsibility for the decision to submit for publication. May 2013 | Volume 8 | Issue 5 | e58867 Results The data for ages at menarche and menopause were not available in the dataset. It also contains longitudinal demographic and socio- economic data from the national censuses of 1960, 1970, 1980, and 1990 [30]. The occupational data were grouped into white- collar workers, blue-collar workers, privates, professionals and others. We also divided Sweden regionally into three groups: North, South and large cities. Ordinal logistic regression was used to calculate odds ratios (ORs) (PROC LOGISTIC; SAS software version 9.2; SAS Institute Inc., Cary, NC, USA). The parity (number of children = 1), the age at first and last childbirth (20–29 years), and the time interval between first and last childbirth (1–4 years) were selected as references. The ORs were adjusted for age at diagnosis, region, occupation and, in some analyses, parity. To assess the effect of the median age at menopause, the analyses were stratified by age (#50 and .50 years) [31,32]. Confidence intervals (95% CI) were calculated assuming a Poisson distribution using T1, N0 and M0 as the references for ‘‘Tis’’ (carcinoma in situ) and ‘‘T2–T4’’, ‘‘N1–N3’’ and ‘‘M1’’, respectively. There was missing information on 7,557 patients for T, on 8,030 patients for N and on 8,124 patients on M in our database. We also excluded TX (N = 1,033), T0 (1,673), NX (1,753) and MX (5,785) from our The analyses shown in Table 1 were repeated in Table 2 by adjusting for parity and by stratifying for time interval between first and last childbirth. Risk of distant metastases was increased in patients with late age at first and last childbirth when children were born in a short interval of 1–4 years; the highest significant OR was 1.85 for an age at last childbirth of 30–39 years. A high-T class was observed for patients with a late age at first and last childbirth when the time interval between first and last childbirth was 5–9 years. The OR for high-T class was 0.77 for patients with early age at first childbirth and a time interval between first and last childbirth of more than 9 years. Additional analyses of parity and time interval between first and last childbirth showed that adjustment for age at first or last childbirth did not change the results (data not shown). May 2013 | Volume 8 | Issue 5 | e58867 PLOS ONE | www.plosone.org 2 Reproductive Factors and TNM in Breast Cancer Table 1. Results Odds ratios (ORs) for TNM classes in postmenopausal breast cancer by reproductive factors. Reproductive factors T1 Tis* vr. T1 T2–T4** vr. T1 N0 N1–N3 vr. N0 M0 M1 vr. M0 N N OR (95%CI) P N OR (95%CI) P N N OR (95%CI) P N N OR (95%CI) P Parity1 1 (Ref.) 1,924 39 1.00 1,620 1.00 2,546 1,005 1.00 2,862 145 1.00 0 1,114 26 1.16 (0.70–1.93) 0.57 816 1.08 (0.96–1.21) 0.21 1,527 552 0.97 (0.85–1.09) 0.58 1,638 55 0.90 (0.65–1.24) 0.51 2 4,806 107 1.16 (0.80–1.68) 0.44 3,043 0.82 (0.76–0.89) ,0.0001 6,030 2,160 0.91 (0.84–1.00) 0.05 6,572 199 0.65 (0.52–0.82) ,0.01 3 2,185 50 1.19 (0.78–1.82) 0.43 1,457 0.83 (0.75–0.91) ,0.01 2,676 1,070 0.99 (0.90–1.10) 0.87 2,943 100 0.69 (0.53–0.89) 0.01 $4 765 12 0.79 (0.41–1.52) 0.47 687 0.98 (0.86–1.11) 0.73 988 435 1.03 (0.90-1.18) 0.68 1,171 49 0.70 (0.50–0.98) 0.04 Total 10,794 234 7,623 13,767 5,222 15,186 548 Age at first childbirth (year)2 20–29 (Ref.) 6,932 148 1.00 4,714 1.00 8,651 3,277 1.00 9,504 322 1.00 #19 1,208 30 1.16 (0.77–1.73) 0.48 742 0.93 (0.84–1.03) 0.18 1,485 601 1.05 (0.95–1.16) 0.37 1,658 74 1.34 (1.03–1.73) 0.03 30–39 1,468 30 0.89 (0.59–1.32) 0.56 1,260 1.20 (1.10–1.31) ,0.0001 1,998 740 0.99 (0.90–1.09) 0.79 2,252 92 1.20 (0.94–1.52) 0.14 $40 72 0 (2) 91 1.84 (1.33–2.53) ,0.01 106 52 1.35 (0.96–1.88) 0.08 134 5 1.14 (0.46–2.82) 0.78 Total 9,680 208 6,807 12,240 4,670 13,548 493 Age at last childbirth (year)2 20–29 (Ref.) 4,503 101 1.00 2,822 1.00 5,576 2,079 1.00 6,101 207 1.00 #19 163 4 1.07 (0.39–2.95) 0.90 119 1.12 (0.87–1.43) 0.38 223 79 0.95 (0.73–1.24) 0.70 250 11 1.25 (0.67–2.33) 0.48 30–39 4,626 95 0.88 (0.66–1.17) 0.38 3,455 1.11 (1.04–1.18) ,0.01 5,927 2,272 1.02 (0.95–1.10) 0.56 6,544 246 1.06 (0.88–1.28) 0.55 $40 388 8 0.83 (0.40–1.74) 0.63 411 1.45 (1.25–1.69) ,0.0001 514 240 1.22 (1.03–1.43) 0.02 653 29 1.12 (0.75–1.68) 0.58 Total 9,680 208 6,807 12,240 4,670 13,548 493 Time interval between first and last childbirth (year)2 1–4 (Ref.) 3,429 73 1.00 2,068 1.00 4,259 1,536 1.00 4,640 112 1.00 5–9 2,762 64 1.12 (0.80–1.58) 0.50 1,833 1.03 (0.95–1.12) 0.52 3,397 1,318 1.05 (0.96–1.14) 0.32 3,714 141 1.40 (1.08–1.80) 0.01 $10 1,524 31 0.91 (0.59–1.40) 0.66 1,268 1.20 (1.09–1.32) ,0.01 1,987 798 1.05 (0.95–1.16) 0.35 2,279 94 1.39 (1.05–1.84) 0.02 Total 7,715 168 5,169 9,643 3,652 10,633 347 Bold type: 95% CI does not include 1.00. Results The ORs were adjusted for: 1. Age at diagnosis, region, and occupation. 2. Age at diagnosis, region, occupation, and parity. *Carcinoma in situ. **The number of cases for T2 (N = 6,098), T3 (871), and T4 (654). doi:10.1371/journal.pone.0058867.t001 PLOS ONE | www.plosone.org 3 May 2013 | Volume 8 | Issue 5 | e5 May 2013 | Volume 8 | Issue 5 | e58867 May 2013 | Volume 8 | Issue 5 | e58867 May 2013 | Volume 8 | Issue 5 | e58867 3 Reproductive Factors and TNM in Breast Cancer Table 2. Odds ratios (ORs) for TNM classes in postmenopausal breast cancer by age at first and last childbirth, stratified by time interval between first and last childbirth. Age at breast cancer diagnosis T1 Tis* vr. T1 T2–T4** vr. T1 N0 N1–N3 vr. N0 M0 M1 vr. Results M0 N N OR (95%CI) P N OR (95%CI) P N N OR (95%CI) P N N OR (95%CI) P Time interval between first and last childbirth 1-4 years Age at first childbirth (year) 20-29 (Ref.) 2,574 55 1.00 1,503 1.00 2,607 1,145 1.00 2,863 75 1.00 #19 277 5 0.84 (0.33–2.13) 0.71 138 0.08 (0.71–1.10) 0.25 20 132 1.14 (0.92–1.42) 0.24 23 5 0.63 (0.25–1.58) 0.33 30–39 569 13 1.00 (0.54–1.87) 1.00 415 1.14 (0.99-1.32) 0.09 1,574 252 0.90 (0.77–1.06) 0.21 1,679 31 1.61 (1.04–2.50) 0.03 $40 9 0 12 2.22 (0.91–5.40) 0.08 58 7 1.79 (0.70–4.58) 0.23 75 1 2.96 (0.37–23.62) 0.31 Total 3,429 73 2,068 1,574 1,536 4,640 112 Age at last childbirth (year) 20–29 (Ref.) 2,148 49 1.00 1,212 1.00 2,607 948 1.00 2,863 53 1.00 #19 19 0 8 0.69 (0.29–1.60) 0.37 20 7 0.92 (0.39–2.20) 0.86 23 0 30–39 1,219 23 0.81 (0.48–1.35) 0.42 809 1.09 (0.97–1.22) 0.18 1,574 556 0.99 (0.87–1.12) 0.84 1,679 56 1.85 (1.25–2.74) ,0.01 $40 43 1 0.81 (0.11–6.22) 0.84 39 1.40 (0.89–2.19) 0.16 58 25 1.19 (0.73–1.92) 0.49 75 3 1.96 (0.58–6.57) 0.28 Total 3,429 73 2,068 4,259 1,536 4,640 112 Time interval between first and last childbirth 5–9 years Age at first childbirth (year) 20–29 (Ref.) 2,142 51 1.00 1,368 1.00 2,595 1,005 1.00 2,826 104 1.00 #19 370 10 1.17 (0.58–2.37) 0.66 219 1.00 (0.83–1.20) 0.99 451 188 1.08 (0.89–1.30) 0.44 482 25 1.60 (1.01–2.53) 0.05 30–39 249 3 0.46 (0.14–1.49) 0.20 245 1.48 (1.22–1.80) ,.0001 350 124 0.92 (0.74–1.15) 0.48 404 12 0.75 (0.41–1.39) 0.36 $40 1 0 1 1.61 (0.1–27.32) 0.74 1 1 2.49 (0.16–40.04) 0.52 2 0 Total 2,762 64 1,833 3,397 1,318 3,714 141 Age at last childbirth (year) 20–29 (Ref.) 1,130 28 667 1.00 1,387 534 1.00 1,483 66 1.00 #19 0 0 1.00 0 0 0 0 0 30–39 1,577 35 0.84 (0.50–1.41) 0.51 1,104 1.14 (1.01–1.30) 0.04 1,937 749 1.02 (0.89–1.17) 0.78 2,142 70 0.73 (0.51–1.03) 0.08 $40 55 1 0.66 (0.09–5.01) 0.68 62 1.73 (1.18–2.55) 0.01 73 35 1.28 (0.84–1.96) 0.25 89 5 1.22 (0.47–3.16) 0.68 Total 2,762 64 1,833 3,397 1,318 3,714 141 Time interval between first and last childbirth $10 years Age at first childbirth (year) 20–29 (Ref.) 1,077 18 1.00 953 1.00 1,416 571 1.00 1,625 60 1.00 #19 417 11 1.46 (0.67–3.20) 0.34 274 0.77 (0.64–0.93) 0.01 525 209 0.99 (0.82–1.20) 0.90 598 33 1.56 (1.00–2.44) 0.05 PLOS ONE | www.plosone.org 4 May 2013 | Volume 8 | Issue 5 | e5886 4 Reproductive Factors and TNM in Breast Cancer Table 2. May 2013 | Volume 8 | Issue 5 | e58867 Results Cont. Time interval between first and last childbirth $10 years Age at first childbirth (year) 30–39 30 2 3.78 (0.80–17.9) 0.09 41 1.34 (0.82–2.18) 0.25 46 18 0.97 (0.55–1.69) 0.90 56 1 0.41 (0.06–3.07) 0.39 $40 0 0 0 0 0 0 0 Total 1,524 31 1,268 1,987 798 2,279 94 Age at last childbirth (year) 20–29 (Ref.) 1,077 0 1.00 53 1.00 112 41 1.00 131 5 1.00 0.96 #19 417 0 0 0 0 0 0 0.96 30–39 30 25 983 1.22 (0.85–1.75) 0.28 1,585 621 1.07 (0.74–1.55) 0.73 1,775 72 0.98 (0.38–2.48) 0.96 $40 0 6 232 1.41 (0.95–2.11) 0.09 290 136 1.28 (0.84–1.94) 0.25 373 17 1.00 (0.35–2.80) 0.99 Total 1,524 31 1,268 1,987 798 2,279 94 Bold type: 95% CI does not include 1.00. Women with two or more children were included. ORs were adjusted for parity, region and occupation. *Carcinoma in situ. doi:10.1371/journal.pone.0058867.t002 PLOS ONE | www.plosone.org 5 May 2013 | Volume 8 | Issue 5 | e58867 Table 2. Cont. Time interval between first and last childbirth $10 years Age at first childbirth (year) 30–39 30 2 3.78 (0.80–17.9) 0.09 41 1.34 (0.82–2.18) 0.25 46 18 0.97 (0.55–1.69) 0.90 56 1 0.41 (0.06–3.07) 0.39 $40 0 0 0 0 0 0 0 Total 1,524 31 1,268 1,987 798 2,279 94 Age at last childbirth (year) 20–29 (Ref.) 1,077 0 1.00 53 1.00 112 41 1.00 131 5 1.00 0.96 #19 417 0 0 0 0 0 0 0.96 30–39 30 25 983 1.22 (0.85–1.75) 0.28 1,585 621 1.07 (0.74–1.55) 0.73 1,775 72 0.98 (0.38–2.48) 0.96 $40 0 6 232 1.41 (0.95–2.11) 0.09 290 136 1.28 (0.84–1.94) 0.25 373 17 1.00 (0.35–2.80) 0.99 Total 1,524 31 1,268 1,987 798 2,279 94 Bold type: 95% CI does not include 1.00. Women with two or more children were included. ORs were adjusted for parity, region and occupation. *Carcinoma in situ. doi:10.1371/journal.pone.0058867.t002 PLOS ONE | www.plosone.org May 2013 | Volume 8 | Issue 5 | e58867 5 Reproductive Factors and TNM in Breast Cancer Table 3. Odds ratios (ORs) for TNM classes in postmenopausal ductal carcinoma by reproductive factors. Reproductive factors T1 Tis* vr. T1 T2–T4** vr. T1 N0 N1–N3 vr. N0 M0 M1 vr. Results M0 N N OR (95%CI) P N OR (95%CI) P N N OR (95%CI) P N N OR (95%CI) P Parity1 1 (Ref.) 1,399 22 1.00 1,033 1.00 1,746 717 1.00 1,979 72 1.00 0 830 20 1.54 (0.83–2.87) 0.17 553 1.08 (0.95–1.25) 0.25 1,115 402 0.92 (0.80–1.07) 0.29 1,211 30 0.90 (0.58–1.41) 0.65 2 3,519 71 1.32 (0.82–2.15) 0.26 2,004 0.84 (0.76–0.93) ,0.01 4,247 1606 0.93 (0.84–1.03) 0.17 4,699 105 0.67 (0.49–0.91) 0.01 3 1,599 31 1.31 (0.75–2.28) 0.34 958 0.85 (0.75–0.95) ,0.01 1,871 784 1.00 (0.89–1.13) 0.95 2,083 55 0.74 (0.52–1.06) 0.10 $4 534 7 0.92 (0.39–2.18) 0.85 440 1.03 (0.88–1.20) 0.73 669 307 1.03 (0.88–1.21) 0.73 799 30 0.84 (0.54–1.30) 0.44 Total 7,881 151 4,988 9,648 3,816 10,771 292 Age at first childbirth (year)2 20–29 (Ref.) 5,029 98 1.00 3,094 1.00 6,027 2394 1.00 6,724 176 1.00 #19 904 20 1.09 (0.67–1.78) 0.73 517 0.95 (0.84–1.07) 0.41 1,077 471 1.08 (0.96–1.22) 0.19 1,227 39 1.20 (0.84–1.71) 0.32 30–39 1,064 13 0.59 (0.33–1.06) 0.08 772 1.13 (1.02–1.26) 0.02 1,359 512 0.96 (0.85–1.07) 0.42 1,526 44 1.13 (0.81–1.59) 0.48 $40 54 0 (2) 52 1.51 (1.02–2.24) 0.04 70 37 1.37 (0.91–2.05) 0.13 83 3 1.46 (0.45–4.70) 0.53 Total 7,051 131 4,435 8,533 3,414 9,560 262 Age at last childbirth (year)2 20–29 (Ref.) 3,327 72 1.00 1,891 1.00 3,936 1562 1.00 4,401 111 1.00 #19 125 2 0.72 (0.17–3.00) 0.65 85 1.16 (0.87–1.55) 0.31 168 64 0.96 (0.72–1.29) 0.80 194 4 0.79 (0.29–2.17) 0.65 30–39 3,328 52 0.73 (0.51–1.06) 0.10 2,211 1.10 (1.01–1.19) 0.02 4,080 1628 1.00 (0.92–1.08) 0.95 4,544 132 1.13 (0.87–1.47) 0.34 $40 271 5 0.82 (0.33–2.06) 0.67 248 1.40 (1.16–1.68) ,0.01 349 160 1.12 (0.92–1.37) 0.25 421 15 1.26 (0.72–2.19) 0.42 Total 7,051 131 4,435 8,533 3,414 9,560 262 Time interval between first and last childbirth (year)2 1–4 (Ref.) 2,528 50 1.00 1,361 1.00 3,002 1143 1.00 3,322 58 1.00 5–9 2,016 39 1.04 (0.68–1.60) 0.84 1,210 1.05 (0.95–1.16) 0.34 2,397 966 1.03 (0.93–1.14) 0.62 2,644 82 1.55 (1.10–2.19) 0.01 $10 1,078 20 0.94 (0.55–1.61) 0.83 818 1.24 (1.10–1.39) ,0.01 1,350 578 1.07 (0.95–1.20) 0.30 1,577 50 1.45 (0.98–2.13) 0.06 Total 5,622 109 3,389 6,749 2,687 7,543 190 Bold type: 95% CI does not include 1.00. The ORs were adjusted for: 1. Age at diagnosis, region, and occupation. 2. Age at diagnosis, region, occupation, and parity. *Carcinoma in situ. Results **The number of cases for T2 (N = 4,133), T3 (484), and T4 (371). doi:10.1371/journal.pone.0058867.t003 PLOS ONE | www.plosone.org 6 May 2013 | Volume 8 | Issue 5 | May 2013 | Volume 8 | Issue 5 | e58867 May 2013 | Volume 8 | Issue 5 | e58867 6 Reproductive Factors and TNM in Breast Cancer Table 4. Odds ratios (ORs) for TNM classes in postmenopausal lobular carcinoma by reproductive factors. Reproductive factors T1 Tis* vr. T1 T2–T4** vr. T1 N0 N1–N3 vr. N0 M0 M1 vr. Results M0 N N OR (95%CI) P N OR (95%CI) P N N OR (95%CI) P N N OR (95%CI) P Parity1 1 (Ref.) 246 3 1.00 303 1.00 404 164 1.00 459 19 1.00 0 146 2 1.04 (0.17–6.49) 0.96 152 0.95 (0.72–1.27) 0.75 216 82 0.98 (0.71–1.35) 0.91 229 6 0.74 (0.29–1.92) 0.54 2 618 11 1.61 (0.44–5.93) 0.47 555 0.77 (0.62–0.94) 0.01 858 320 0.90 (0.72–1.13) 0.37 950 28 0.75 (0.41–1.36) 0.34 3 318 6 1.57 (0.38–6.45) 0.53 277 0.72 (0.57–0.91) 0.01 430 178 0.94 (0.73–1.22) 0.66 471 19 1.01 (0.52–1.94) 0.98 $4 92 4 2.83 (0.6–13.32) 0.19 130 1.04 (0.75–1.44) 0.80 138 78 1.20 (0.85–1.68) 0.30 181 6 0.72 (0.28–1.85) 0.49 Total 1,420 26 1,417 2,046 822 2,290 78 Age at first childbirth (year)2 20–29 (Ref.) 919 17 1.00 846 1.00 1,293 513 1.00 1,423 40 1.00 #19 152 2 0.65 (0.14–2.88) 0.56 125 0.89 (0.69–1.16) 0.39 203 79 0.94 (0.71–1.26) 0.69 226 15 2.23 (1.20–4.16) 0.01 30–39 194 5 1.29 (0.46–3.64) 0.63 271 1.43 (1.16–1.77) ,0.01 315 137 1.11 (0.88–1.40) 0.36 383 17 1.50 (0.83–2.71) 0.17 $40 9 0 23 2.85 (1.29–6.28) 0.01 19 11 1.40 (0.65–3.00) 0.39 29 0 Total 1,274 24 1,265 1,830 740 2,061 72 Age at last childbirth (year)2 20–29 (Ref.) 565 2 1.00 494 1.00 801 301 1.00 876 32 1.00 #19 19 0 15 0.85 (0.42–1.72) 0.66 29 8 0.75 (0.33–1.66) 0.47 31 1 0.82 (0.11–6.32) 0.85 30–39 628 20 7.86 (1.81–34.20) 0.01 662 1.14 (0.96–1.34) 0.14 904 381 1.10 (0.91–1.32) 0.32 1,020 34 0.88 (0.53–1.45) 0.61 $40 62 2 8.08 (1.07–61.15) 0.04 94 1.51 (1.06–2.15) 0.02 96 50 1.23 (0.85–1.80) 0.27 134 5 0.85 (0.32–2.28) 0.75 Total 1,274 24 1,265 1,830 740 2,061 72 Time interval between first and last childbirth (year)2 1–4 (Ref.) 439 4 1.00 389 1.00 609 233 1.00 679 16 1.00 5–9 369 9 2.59 (0.78–8.66) 0.12 338 0.98 (0.80–1.20) 0.83 501 209 1.03 (0.82–1.29) 0.81 560 24 1.77 (0.93–3.40) 0.08 $10 214 7 2.94 (0.83–10.44) 0.10 232 1.10 (0.86–1.39) 0.45 308 132 0.99 (0.76–1.28) 0.91 355 12 1.22 (0.56–2.64) 0.62 Total 1,022 20 959 1,418 574 1,594 52 Bold type: 95% CI does not include 1.00. The ORs were adjusted for: 1. Age at diagnosis, region, and occupation. 2. Age at diagnosis, region, occupation, and parity. *Carcinoma in situ. **The number of cases for T2 (N = 1,106), T3 (236), and T4 (75). Results doi:10.1371/journal.pone.0058867.t004 May 2013 | Volume 8 | Issue 5 | e58867 May 2013 | Volume 8 | Issue 5 | e58867 May 2013 | Volume 8 | Issue 5 | e58867 7 7 Reproductive Factors and TNM in Breast Cancer Table 5. Odds ratios (ORs) for TNM classes in premenopausal ductal carcinoma by reproductive factors. Reproductive factors T1 Tis* vr. T1 T2–T4** vr. T1 N0 N1–N3 vr. N0 M0 M1 vr. Results M0 N N OR (95%CI) P N OR (95%CI) P N N OR (95%CI) P N N OR (95%CI) P Parity1 1 (Ref.) 280 5 1.00 207 1.00 330 174 1.00 392 8 1.00 0 235 8 1.79 (0.57–5.59) 0.32 252 1.44 (1.11–1.85) –0.01 343 180 0.99 (0.76–1.28) 0.93 408 14 1.67 (0.69–4.04) 0.26 2 830 24 1.67 (0.63–4.45) 0.30 528 0.86 (0.70–1.06) 0.16 949 481 0.97 (0.78–1.20) 0.76 1,079 33 1.46 (0.67–3.19) 0.35 3 358 8 1.39 (0.45–4.36) 0.57 245 0.94 (0.73–1.20) 0.59 393 235 1.14 (0.89–1.46) 0.30 488 8 0.77 (0.28–2.09) 0.61 $4 100 2 1.33 (0.25–7.11) 0.74 56 0.77 (0.53–1.13) 0.18 108 58 1.04 (0.72–1.52) 0.83 131 2 0.75 (0.15–3.62) 0.72 Total 1,803 47 1,288 2,123 1,128 2,498 65 Age at first childbirth (year)2 20–29 (Ref.) 1,037 30 1.00 640 1.00 1,159 602 1.00 1,355 37 1.00 #19 79 2 0.98 (0.22–4.28) 0.97 66 1.43 (1.01–2.03) 0.04 94 56 1.18 (0.83–1.68) 0.35 114 2 0.64 (0.15–2.75) 0.55 30–39 438 6 0.48 (0.20–1.19) 0.12 324 1.25 (1.04–1.50) 0.02 511 283 1.10 (0.92–1.32) 0.30 606 12 0.81 (0.41–1.59) 0.54 $40 14 1 2.55 (0.31–21.04) 0.38 6 0.80 (0.30–2.10) 0.65 16 7 0.90 (0.37–2.23) 0.83 15 0 Total 1,568 39 1,036 1,780 948 2,090 51 Age at last childbirth (year)2 20–29 (Ref.) 538 14 1.00 345 1.00 605 314 1.00 706 24 1.00 #19 7 0 8 1.87 (0.66–5.29) 0.24 13 4 0.67 (0.21–2.08) 0.48 15 0 30–39 973 23 1.07 (0.54–2.12) 0.86 640 1.10 (0.92–1.30) 0.30 1,094 598 1.10 (0.93–1.31) 0.28 1,288 27 0.69 (0.39–1.21) 0.19 $40 50 2 1.85 (0.40–8.59) 0.43 43 1.58 (1.02–2.44) 0.04 68 32 1.04 (0.66–1.62) 0.88 81 0 Total 1,568 39 1,036 1,780 948 2,090 51 Time interval between first and last childbirth (year)2 1–4 (Ref.) 711 18 1.00 463 1.00 814 412 1.00 927 25 1.00 5–9 382 14 1.53 (0.73–3.18) 0.26 241 1.00 (0.81–1.22) 0.98 427 233 1.11 (0.90–1.36) 0.33 505 14 1.02 (0.52–2.00) 0.96 $10 181 2 0.47 (0.11–2.10) 0.32 118 1.05 (0.81–1.37) 0.72 193 120 1.27 (0.97–1.65) 0.08 248 4 0.59 (0.20–1.75) 0.34 Total 1,274 34 822 1,434 765 1,680 43 Bold type: 95% CI does not include 1.00. The ORs were adjusted for: 1. Age at diagnosis, region, and occupation. 2. Age at diagnosis, region, occupation, and parity. *Carcinoma in situ. **The number of cases for T2 (N = 1,047), T3 (176), and T4 (65). Reproductive Factors and TNM in Breast Cancer Reproductive Factors and TNM in Breast Cancer Data for postmenopausal ductal cancer are shown in Table 3. As nearly 70% of all breast cancers were ductal, the ORs were almost identical to those shown in Table 1. In contrast, many of the significant effects shown in Table 1 were reinforced for lobular cancer (Table 4). These included decreased ORs for high-T class (0.77 and 0.72 when parity was 2 or 3, respectively, reversely, when parity was equal or greater than 4, the OR for T4 class increased: N = 13, OR = 2.75, 95% CI: 1.12–6.73), increased ORs for high-T class according to age at first and last childbirth (2.85 when age at first childbirth was over 39 years) and an increased OR for distant metastases (2.23 when age at first childbirth was less than 20 years). A novel effect was noted for lobular carcinoma in situ for which the OR was 7.86 when age at last childbirth was 30–39 years. metastases in pre- and postmenopausal patients [9,10]. Another explanation could be a non-attendance at invitational mammog- raphy screening, particularly among nulliparous women. Yet national mammography screening is attended by 81% of those invited in Sweden and mammography outside this program is also available thought the country [41,42]. A study on 10,703 Danish women with breast cancer reported that early age at first childbirth was associated with a poor breast cancer prognosis [43]. We found accordingly that an early age at first childbirth increased the risk of high-T class in premenopausal ductal carcinoma (OR = 1.43) and increased the risk of metastases in postmenopausal cancer of particularly lobular carcinoma (2.23) while the effect on T class was opposite; this was the only instance where low T class was associated with the risk of metastases. According to Table 2, the discrepancy between low T class and metastasis was limited to those with early age at first childbirth who had a long time interval between first and last childbirth. The database included 4,328 cases of premenopausal ductal carcinoma, accounting for 77% of premenopausal cancers (Table 5). The main differences to postmenopausal ductal carcinoma were that for premenopausal cancer nulliparity associated with increased risk of high-T class (1.44). It was mainly caused by T4 class (N = 31, OR = 3.37, 95%CI: 1.66–6.85). Conclusions In summary, increasing parity was protective against high-T class and metastasis. Late age at first and last childbirth were risk factors for high-T class in almost all postmenopausal breast cancers and the effects were stronger for lobular than ductal histology. Low parity and long time interval between first and last childbirth were risk factors for distant metastases. The observed variation in the associations of reproductive factors with TNM classes suggests that hormonal and other physiological changes during pregnancy and menopause play an important role in determining T class and metastatic spread, with implications to prognosis. The current decline in parity and delayed age at first childbirth in many global populations may counterbalance the favorable achievements of prevention, screening and treatment of breast cancer. Reproductive factors induce physiological changes in the mammary gland such as rapid proliferation of breast tissue [11– 13,36]. Previous studies reported that nulliparity and late age at first childbirth are related to aggressive tumor behavior [37–40]. Our results suggest that high-T class may mediate such effects: nulliparity was associated with the risk of high-T class, particularly in premenopausal ductal carcinomas and late age at first childbirth was associated with high-T class in postmenopausal ductal and lobular carcinomas. These findings suggest that physiological changes related to parity and age at first childbirth during pregnancy play a major role in the risk of high-T class and Discussion In this large nation-wide follow-up study of 32,924 Swedish women with breast cancer, we found for postmenopausal cancer that multiparity was associated with a decreased risk of high-T class and distant metastases, while a late age at first or last childbirth increased the risk of high-T class. There was a general correlation between high-T class and distant metastases but not with lymph node metastases, which appeared not to be affected by reproductive factors. Risk of distant metastases was increased particularly in patients with a late age at first or last childbirth when the time interval between first and last childbirth was short, which is a typical reproductive pattern of educated women [33]. A population-based study in Finland showed that short time interval between first and last childbirth is a protective factor for lobular carcinoma, but not for ducal carcinoma [14]. In our study, the only significant effect was on T class in postmenopausal ductal carcinoma. Pregnancy influences the level of estrogen and increases the risk of breast cancer in a short term, but decreases the risk in a long term [46–51]. Furthermore, pregnancy may also induce changes in hormone levels that may affect tumor progression in postmenopausal cases [52,53]. Whether the level of estrogen influences the risk of high-T class and metastasis remains to be investigated. Our study used information on breast cancer patients diagnosed in the period 2002 to 2008, during which the histological classification system did not vary. Thanks to a complete cancer registration with verified histology, our study should be free of selection bias [28,34]. Our findings on TNM classes, as prognostic data for breast cancer, suggested survival effects relating to reproductive factors but these could not be directly studied because the TNM classification was started first in 2002 [23–25]. Several limitations should be considered in interpreting our results. Some 24% of T, N and M classes were missing in the Cancer Registry. Neither were data available on age at menarche, breast feeding, obesity, oral contraceptive use, mammographic breast density, breast self-exam, hormone replacement therapy and hormone receptor status [10,18,19,35]. Reproductive Factors and TNM in Breast Cancer High-T class was also increased in patients with age at first childbirth of less than 20 years whereas age at first childbirth of over 39 years was not a risk factor. Within the limits of detection, no reproductive parameter changed the ORs for carcinoma in situ or for lymph node or distant metastases. The association of age at last childbirth and breast cancer risk or prognosis is unclear [12,13]. A case-control study reported an increased risk of breast cancer of 1.10 (95CI%: 1.03–1.16) for each 5-year increase in age at last childbirth [13]. We found that a late age at last childbirth increased the risk of high-T class in postmenopausal ductal and lobular carcinomas and premeno- pausal ductal carcinoma. One study reported that a late age at childbirth and nulliparity are more strongly associated with carcinoma in situ than invasive carcinoma in premenopausal patients [18]. In our data, the case numbers for premenopausal carcinoma in situ were small and only strong effects could have been detected. However, such strong effects (OR 8.00) were noted for postmenopausal lobular carcinoma in situ patients with a late age at last childbirth [44,45]. Results doi:10.1371/journal.pone.0058867.t005 PLOS ONE | www.plosone.org May 2013 | Volume 8 | Issue 5 | e58867 8 References van den Brandt PA, Spiegelman D, Yaun SS, Adami HO, Beeson L, et al. (2000) Pooled analysis of prospective cohort studies on height, weight, and breast cancer risk. Am J Epidemiol 152: 514–527. 9. Li CI, Daling JR, Malone KE, Bernstein L, Marchbanks PA, et al. (2006) Relationship between established breast cancer risk factors and risk of seven different histologic types of invasive breast cancer. Cancer Epidemiol Biomarkers Prev 15: 946–954. J p 36. Russo J, Moral R, Balogh GA, Mailo D, Russo IH (2005) Th 36. Russo J, Moral R, Balogh GA, Mailo D, Russo IH (2005) The protective role of pregnancy in breast cancer. Breast Cancer Res 7: 131–142. 10. Newcomb PA, Trentham-Dietz A, Hampton JM, Egan KM, Titus-Ernstoff L, et al. (2011) Late age at first full term birth is strongly associated with lobular breast cancer. Cancer 117: 1946–1956. 37. Alsaker MD, Opdahl S, Asvold BO, Romundstad PR, Vatten LJ (2011) The association of reproductive factors and breastfeeding with long term survival from breast cancer. Breast Cancer Res Treat 130: 175–182. 11. Granstrom C, Sundquist J, Hemminki K (2008) Population attributable risks for breast cancer in Swedish women by morphological type. Breast Cancer Res Treat 111: 559–568. 38. Butt S, Borgquist S, Anagnostaki L, Landberg G, Manjer J (2009) Parity and age at first childbirth in relation to the risk of different breast cancer subgroups. Int J Cancer 125: 1926–1934. 12. Rosen PP, Lesser ML, Senie RT, Duthie K (1982) Epidemiology of breast carcinoma IV: age and histologic tumor type. J Surg Oncol 19: 44–51. 39. Chan TF, Wu CH, Changchien CC, Yang CY (2011) Mortality from breast, endometrial and ovarian cancers among grand multiparous women in Taiwan. Aust N Z J Obstet Gynaecol 51: 548–552. 13. Chie WC, Hsieh C, Newcomb PA, Longnecker MP, Mittendorf R, et al. (2000) Age at any full-term pregnancy and breast cancer risk. Am J Epidemiol 151: 715–722. 40. Warren Andersen S, Newcomb PA, Hampton JM, Titus-Ernstoff L, Egan KM, et al. (2011) Reproductive factors and histologic subtype in relation to mortality after a breast cancer diagnosis. Breast Cancer Res Treat 130: 975–980. 14. Hinkula M, Pukkala E, Kyyronen P, Kauppila A (2001) Grand multiparity and the risk of breast cancer: population-based study in Finland. Cancer Causes Control 12: 491–500. 41. Lagerlund M, Maxwell AE, Bastani R, Thurfjell E, Ekbom A, et al. References 29. Cowherd SM (2012) Tumor staging and grading: a primer. Methods Mol Biol 823: 1–18. 1. Shrestha LB, Heisler EJ (2011) The Changing Demographic Profile of the United States. 30. Hemminki K, Ji J, Brandt A, Mousavi SM, Sundquist J (2010) The Swedish Family-Cancer Database 2009: Prospects for histology-specific and immigrant studies. Int J Cancer 126: 2259–2267. 2. Morgan SP, Taylor MG (2006) Low Fertility at the Turn of the Twenty-First Century. Annu Rev Sociol 32: 375–399. y 3. The ESHRE Capri Workshop Group (2010) Europe the continent with the lowest fertility. Hum Reprod Update 16: 590–602. 31. Rodstrom K, Bengtsson C, Milsom I, Lissner L, Sundh V, et al. (2003) Evidence for a secular trend in menopausal age: a population study of women in Gothenburg. Menopause 10: 538–543. 4. Castro Martin T (1995) Women’s education and fertility: results from 26 Demographic and Health Surveys. Stud Fam Plann 26: 187–202. 4. Castro Martin T (1995) Women’s education and fertility: res Demographic and Health Surveys. Stud Fam Plann 26: 187–202 g p 32. Hidayet NM, Sharaf SA, Aref SR, Tawfik TA, Moubarak II (1999) Correlates of age at natural menopause: a community-based study in Alexandria. East Mediterr Health J 5: 307–319. 5. Boyle P, Levin B (2008) World Cancer Report 2008: Lyon: IARC. 6. Greene FL, Page DL, Fleming ID, Fritz A, Balch CM, et al. (2002) AJCC (American Joint Committee on Cancer) Cancer Staging Manual, 6th ed New York: Springer-Verlag. 33. Menvielle G, Kunst AE, van Gils CH, Peeters PH, Boshuizen H, et al. (2011) The contribution of risk factors to the higher incidence of invasive and in situ breast cancers in women with higher levels of education in the European prospective investigation into cancer and nutrition. Am J Epidemiol 173: 26–37. 7. Phipps AI, Li CI, Kerlikowske K, Barlow WE, Buist DS (2010) Risk factors for ductal, lobular, and mixed ductal-lobular breast cancer in a screening population. Cancer Epidemiol Biomarkers Prev 19: 1643–1654. p p p 8. Reeves GK, Pirie K, Green J, Bull D, Beral V (2009) Reproductive factors and specific histological types of breast cancer: prospective study and meta-analysis. Br J Cancer 100: 538–544. p p g p 34. Centre for Epidemiology (2007) Cancer incidence in Sweden 2005. Stockholm The National Board of Health and Welfare. p p g 34. Centre for Epidemiology (2007) Cancer inciden The National Board of Health and Welfare. 35. References Am J Epidemiol 153: 1079–1084. 47. Wiseman RA (2004) Breast cancer: critical data analysis concludes that estrogens are not the cause, however lifestyle changes can alter risk rapidly. J Clin Epidemiol 57: 766–772. 22. Weiss HA, Brinton LA, Brogan D, Coates RJ, Gammon MD, et al. (1996) Epidemiology of in situ and invasive breast cancer in women aged under 45. Br J Cancer 73: 1298–1305. p 48. Gupta PB, Kuperwasser C (2006) Contributions of estrogen to ER-negative breast tumor growth. J Steroid Biochem Mol Biol 102: 71–78. 23. Sant M, Allemani C, Capocaccia R, Hakulinen T, Aareleid T, et al. (2003) Stage at diagnosis is a key explanation of differences in breast cancer survival across Europe. Int J Cancer 106: 416–422. 49. Pike MC, Wu AH, Spicer DV, Lee S, Pearce CL (2007) Estrogens, progestins, and risk of breast cancer. Ernst Schering Found Symp Proc: 127–150. 24. Carey LA, Metzger R, Dees EC, Collichio F, Sartor CI, et al. (2005) American Joint Committee on Cancer tumor-node-metastasis stage after neoadjuvant chemotherapy and breast cancer outcome. J Natl Cancer Inst 97: 1137–1142. d risk of breast cancer. Ernst Schering Found Symp Proc: 127–150. 50. Kroman N, Wohlfahrt J, Andersen KW, Mouridsen HT, Westergaard T, et al. (1997) Time since childbirth and prognosis in primary breast cancer: population based study. BMJ 315: 851–855. 25. Olivotto IA, Chua B, Allan SJ, Speers CH, Chia S, et al. (2003) Long-term survival of patients with supraclavicular metastases at diagnosis of breast cancer. J Clin Oncol 21: 851–854. 51. Dodds L, Fell DB, Joseph KS, Dewar R, Scott H, et al. (2008) Relationship of time since childbirth and other pregnancy factors to premenopausal breast cancer prognosis. Obstet Gynecol 111: 1167–1173. J 26. Hemminki K, Ji J, Brandt A, Mousavi SM, Sundquist J (2009) The Swedish Family-Cancer Database 2009: prospects for histology-specific and immigrant studies. Int J Cancer 126: 2259–2267. 52. Lonning PE, Helle SI, Johannessen DC, Ekse D, Adlercreutz H (1996) Influence of plasma estrogen levels on the length of the disease-free interval in postmenopausal women with breast cancer. Breast Cancer Res Treat 39: 335–341. J 27. Hemminki K, Li X, Plna K, Granstrom C, Vaittinen P (2001) The nation-wide Swedish family-cancer database – updated structure and familial rates. Acta Oncol 40: 772–777. 53. References (2002) Sociodemographic predictors of non-attendance at invitational mammography screening – a population-based register study (Sweden). Cancer Causes Control 13: 73–82. 15. Vogel VG (2008) Epidemiology, genetics, and risk evaluation of postmenopausal women at risk of breast cancer. Menopause 15: 782–789. 42. Olsson S, Andersson I, Karlberg I, Bjurstam N, Frodis E, et al. (2000) Implementation of service screening with mammography in Sweden: from pilot study to nationwide programme. J Med Screen 7: 14–18. 16. Jacobson HI, Lemanski N, Narendran A, Agarwal A, Bennett JA, et al. (2008) Hormones of pregnancy, alpha-feto protein, and reduction of breast cancer risk. Adv Exp Med Biol 617: 477–484. p 17. Kobayashi S, Sugiura H, Ando Y, Shiraki N, Yanagi T, et al. (2012) Reproductive history and breast cancer risk. Breast Cancer. 43. Kroman N, Wohlfahrt J, Andersen KW, Mouridsen HT, Westergaard T, et al. (1998) Parity, age at first childbirth and the prognosis of primary breast cancer. Br J Cancer 78: 1529–1533. 18. Reinier KS, Vacek PM, Geller BM (2007) Risk factors for breast carcinoma in situ versus invasive breast cancer in a prospective study of pre- and post- menopausal women. Breast Cancer Res Treat 103: 343–348. J 44. Lambe M, Hsieh CC, Tsaih SW, Ekbom A, Trichopoulos D, et al. (1998) Parity, age at first birth and the risk of carcinoma in situ of the breast. Int J Cancer 77: 330–332. 19. Li CI, Malone KE, Porter PL, Weiss NS, Tang MT, et al. (2003) Reproductive and anthropometric factors in relation to the risk of lobular and ductal breast carcinoma among women 65–79 years of age. Int J Cancer 107: 647–651. 45. Ma H, Henderson KD, Sullivan-Halley J, Duan L, Marshall SF, et al. (2010) Pregnancy-related factors and the risk of breast carcinoma in situ and invasive breast cancer among postmenopausal women in the California Teachers Study cohort. Breast Cancer Res 12: R35. 20. Albrektsen G, Heuch I, Thoresen S, Kvale G (2006) Clinical stage of breast cancer by parity, age at birth, and time since birth: a progressive effect of pregnancy hormones? Cancer Epidemiol Biomarkers Prev 15: 65–69. cohort. Breast Cancer Res 12: R35. 46. Persson I (2000) Estrogens in the causation of breast, endometrial and ovarian cancers – evidence and hypotheses from epidemiological findings. J Steroid Biochem Mol Biol 74: 357–364. 21. Wohlfahrt J, Andersen PK, Mouridsen HT, Melbye M (2001) Risk of late-stage breast cancer after a childbirth. Author Contributions Conceived and designed the experiments: KH. Performed the experiments: SMM KH. Analyzed the data: SMM AF KH. Contributed reagents/ materials/analysis tools: KS KH. Wrote the paper: SMM AF KH. May 2013 | Volume 8 | Issue 5 | e58867 PLOS ONE | www.plosone.org 9 Reproductive Factors and TNM in Breast Cancer References Ganz PA, Land SR (2008) Risks, benefits, and effects on quality of life of selective estrogen-receptor modulator therapy in postmenopausal women at increased risk of breast cancer. Menopause 15: 797–803. 28. The National Board of Health and Welfare (2010) Cancer Incidence in Sweden 2010. May 2013 | Volume 8 | Issue 5 | e58867 10 PLOS ONE | www.plosone.org
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ДОСЛІДЖЕННЯ ПОШИРЕНОСТІ ТА СПОСОБІВ ВИЯВЛЕННЯ ЕЙМЕРІОЗУ СЕРЕД КРОЛИКІВ ЗАЛЕЖНО ВІД РІЗНИХ МЕТОДІВ УТРИМАННЯ
Vìsnik Sumsʹkogo nacìonalʹnogo agrarnogo unìversitetu. Serìâ: Veterinarna medicina
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Супрун Юлія Олександрівна Супрун Юлія Олександрівна аспірант кафедри акушерства та хірургії Сумський національний аграрний університет, м. Суми, Україна ORCID: 0000-0001-8035-6282 ulianagerasimova@gmail.com Однією з ключових труднощів у процесі вирощування кроликів є еймеріоз незалежно від методів їх утримання ця хвороба впливає на тварин усіх вікових груп призводячи до зменшення приросту ваги погіршення ефектив- ності засвоєння корму підвищеної захворюваності. р у щ р Мета дослідження було визначення поширеності та способів виявлення еймеріозу серед кроликів залежно від різних методів утримання проводяться з метою вдосконалення стратегій боротьби з цим захворюванням і вдо- сконалити методи карантину. р у Протягом періоду з 2019 по 2021 рік було проведено дослідження в господарствах з різним рівнем потужності в чотирьох областях: Запорізька, Донецька, Харківська та Сумська. Загалом було обстежено 20 господарств, де тримали кроликів різних порід. р р р р У фермерських та приватних кролівницьких господарствах виділяли E. іntestinalis, E. magna, E. media, E. piriforms, E. perforans, E. irresidua. Доведено, що в зимовий період рівень ооцист був від 12±1,2 до 34±2,4 в п.з. мікроскопу. У літній період рівень інвазії на зменшувався, і коливався в межах від максимального – 15±1,2 (EI = 19 %), до мінімального – 5±2,0 (EI = 6 %). Дослідження підтвердило, що в умовах утримання в металевих клітках у фермерських господарствах, за дотримання санітарно-гігієнічних норм та регулярної дезінфекції примі- щень, рівень інвазії становив від 15% до 42% у зимовий період та від 6% до 19% у літній період. При аналізі даних, отриманих з приватних господарств, де кролі утримуються в дерев'яних клітках з глибокою підстилкою, було встановлено, що рівень інвазії становив від 56% до 100% у холодний період та від 29% до 70% у теплий період. Використання металевих кліток для утримання кролів з дотриманням санітарно-гігієнічних вимог та вчасної дезінфекції сприяє зниженню рівня поширеності паразитарних заражень. р р р р р ова: еймеріоз кролів, біологічний цикл еймерій, інтенсивність інвазії, способи утримання кролів. ф ц р р р р р р Ключові слова: еймеріоз кролів, біологічний цикл еймерій, інтенсивність інвазії, спо ф ц р р р р р р Ключові слова: еймеріоз кролів, біологічний цикл еймерій, інтенсивність інвазії, способи утримання кролів. DOI https://doi.org/10.32782/bsnau.vet.2023.3.17 Вступ. Галузь кролівництва в Україні лише починає набирати свої оберти. За рахунок швидкого росту та дієтичним властивостям м’яса. Кролики – це альтерна- тивний товар для тваринництва м'ясні запаси, а також домашні тварини та лабораторні тварини (El-Shall et al., 2022). Супрун Юлія Олександрівна М'ясо кролика має високий вміст білка, лінолено- вої кислоти, кальцію і фосфору, низький вміст жиру та холестерину, Також завдяки фізіологічним особливос- тям кролів в процесі їх вирощування використовується мінімальна кількість хімікотерапевтичних засобів. Тому таку продукцію можна вважати органічною. Що наразі є актуальним для харчової промисловості та зберігання екологічного балансу в цілому (Saeed & Alkheraije, 2023). Вступ. Галузь кролівництва в Україні лише починає набирати свої оберти. За рахунок швидкого росту та дієтичним властивостям м’яса. Кролики – це альтерна- тивний товар для тваринництва м'ясні запаси, а також домашні тварини та лабораторні тварини (El-Shall et al., 2022). М'ясо кролика має високий вміст білка, лінолено- вої кислоти, кальцію і фосфору, низький вміст жиру та холестерину, Також завдяки фізіологічним особливос- тям кролів в процесі їх вирощування використовується мінімальна кількість хімікотерапевтичних засобів. Тому таку продукцію можна вважати органічною. Що наразі є актуальним для харчової промисловості та зберігання екологічного балансу в цілому (Saeed & Alkheraije, 2023). Підвищення інтенсивності вирощування кролів та зосередження поголів'я на обмеженій території збіль- шує можливість передачі захворювань. Оскільки еймерії постійно присутні у шлунково-кишковому тракті кролів, передача збудника від матері до дитини відбувається навіть у перші дні життя. Ооцисти кокцидій виділяються разом з фекаліями кролів, і вони можуть довгий час існу- вати в навколишньому середовищі, достатньо одного ооциста для зараження нового господаря. Молоді кро- ленята можуть заразитися цим паразитом, споживаючи сіно, воду та навіть фекалії від матері чи одне одного (Ogolla et al., 2018).. ( g , ) Кокцидіоз (еймеріоз) кролів (El-Ashram et al., 2019)., яке спричиняється різними видами роду Eimeria з класу Coccidia. Увідомлено про одинадцять видів еймерій (Oryctolagus cuniculus) відноситься до паразитарних захво- рювань (Athanasiou et al., 2023), що зустрічаються у шлун- ково-кишковому тракті, а також один вид, що може жити у жовчних протоках – Eimeria stiedae (Bochyńska et al., 2022). Кролики можуть заразитися кокцидіями з оточуючого середовища, і це дуже часто стається в селекційних цен- трах та на інших підприємствах, де зосереджена велика кількість тварин. Для того щоб ооцисти (яйця) стали інвазивними, потрібно принаймні два дні в умовах воло- гості. Крім того, кролики можуть заразитися, споживаючи траву та комбікорм, які містять заражені ооцисти ейме- рій. У таких умовах важливо ретельно проводити дезін- фекцію та знезаражування приміщень для утримання тварин (Xiao et al., 2022). Кокцидіоз (еймеріоз) кролів (El-Ashram et al., 2019)., яке спричиняється різними видами роду Eimeria з класу Coccidia. УДК 636.4.03 УДК 636.4.03 УДК 636.4.03 Вісник Сумського національного аграрного університету Серія «Ветеринарна медицина», випуск 3 (62), 2023 ДОСЛІДЖЕННЯ ПОШИРЕНОСТІ ТА СПОСОБІВ ВИЯВЛЕННЯ ЕЙМЕРІОЗУ СЕРЕД КРОЛИКІВ ЗАЛЕЖНО ВІД РІЗНИХ МЕТОДІВ УТРИМАННЯ Шкромада Оксана Іванівна доктор ветеринарних наук, професор Сумський національний аграрний університет, м. Суми, Україна ORCID: 0000-0003-1751-7009 oshkromada@gmail.com Шкромада Оксана Іванівна доктор ветеринарних наук, професор Сумський національний аграрний університет, м. Суми, Україна ORCID: 0000-0003-1751-7009 oshkromada@gmail.com Супрун Юлія Олександрівна Проведення профілактичної дезінфекції кліток та приміщень було здійснено за допомогою засобу "Тетра- септ" (виробник: ПП «Кронос Агро», Україна) в кількості 0,05 л на 1 м2. Профілактика кокцидіозу залежить від належного санітарного стану та збереження підстилки сухими. Не допускати забруднення каловими масами води та їжі. Також потрібно уникати харчування кролів з підлоги. Одним з варіантів зменшення кількості ооцист є наявність вигульних майданчиків для кролів. Сонячне ультрафіоле- тове світло знищує яйця кокцидій (Sinha et al., 2022). Цей засіб також відомий своїми дезінвазійними властивостями щодо ооцист еймерій. Результати. Життєвий цикл кокцидій підлягає впливу різних чинників, таких як спосіб утримання, вік тварин, сезон року та інші фактори. З огляду на це, для більш докладного дослідження кокцидіозу (еймеріозу), захво- рювання, збудником якого є кокцидії, прогнозування зростання інвазії, розроблення планів профілактичних та терапевтичних заходів з урахуванням сезонних варіацій, були проведені наукові дослідження щодо виявлення кокцидіозу у господарствах, які займаються утриманням кролів різного типу та спрямування (див. Таблиця 1). Мета роботи: визначити географічні особливості розповсюдженості видів кокцидій кролів та залежність випадків захворювання від способу утримання тварин та санітарного стану кліток. Матеріали і методи досліджень. Дослідження про- водили з 2019 по 2021 роки у чотирьох областях: Запо- Таблиця 1 Таблиця Склад видів кокцидій, виявлених на фермерських та приватних господарствах, де проводиться утримання кролів Морфологічні види еймерій Форми власності кролівницьких господарств фермерські приватні Донецька область E. irresidua ++ +++ E. іntestinalis – + E. magna + ++ E. perforans – + E. media + ++ E. stiedae – + Запорізька область E. magna + ++ E. media ++ +++ E. irresidua ++ +++ E. stiedae – + E. іntestinalis + + Сумська область E. exigua + +++ E. flavescens – + E. media + +++ E. piriforms + +++ E. perforans – + E. magna + + Харківська область E. perforans – + E. іntestinalis + ++ E. irresidua + ++ E. media + +++ E. piriforms – + E. magna – ++ римітки: «++++» – 75 – 100% розповсюдження видів «+++» – 50 – 75%; «++» – 25 -50% розповсюдженності; «+» до 25 еймерії в господарстві відсутні. Примітки: «++++» – 75 – 100% розповсюдження видів «+++» – 50 – 75%; «++» – 25 -50% розповсюдженності; «+» до 25%; «–» – еймерії в господарстві відсутні. Примітки: «++++» – 75 – 100% розповсюдження видів «+++» – 50 – 75%; «++» – 25 -50% розповсюдженності; «+» до 25%; «–» – еймерії в господарстві відсутні. Супрун Юлія Олександрівна Увідомлено про одинадцять видів еймерій (Oryctolagus cuniculus) відноситься до паразитарних захво- рювань (Athanasiou et al., 2023), що зустрічаються у шлун- ково-кишковому тракті, а також один вид, що може жити у жовчних протоках – Eimeria stiedae (Bochyńska et al., 2022). Кролики можуть заразитися кокцидіями з оточуючого середовища, і це дуже часто стається в селекційних цен- трах та на інших підприємствах, де зосереджена велика кількість тварин. Для того щоб ооцисти (яйця) стали інвазивними, потрібно принаймні два дні в умовах воло- гості. Крім того, кролики можуть заразитися, споживаючи траву та комбікорм, які містять заражені ооцисти ейме- рій. У таких умовах важливо ретельно проводити дезін- фекцію та знезаражування приміщень для утримання тварин (Xiao et al., 2022). Підвищення інтенсивності вирощування кролів та зосередження поголів'я на обмеженій території збіль- шує можливість передачі захворювань. Оскільки еймерії постійно присутні у шлунково-кишковому тракті кролів, передача збудника від матері до дитини відбувається навіть у перші дні життя. Ооцисти кокцидій виділяються разом з фекаліями кролів, і вони можуть довгий час існу- вати в навколишньому середовищі, достатньо одного Вісник Сумського національного аграрного університету Серія «Ветеринарна медицина», випуск 3 (62), 2023 118 Серія «Ветеринарна медицина», випуск 3 (62), 2023 Печінковий кокцидіоз викликається Eimeria stiedai. Молоді кролики можуть бути дуже сприйнятливими, осо- бливо якщо потрапляють у середовище із високим рів- нем інвазії. Зараження тварин Eimeria stiedai може при- звести до непрохідності жовчних протоків та фіброзних утворень у печінці. Клінічно це виглядає як втрата ваги, діарея, асцит, та жовтяниця, залежно від тяжкості інфек- ції. Eimeria perforans, E. magna, E. media та E. irresidua – це чотири основні види, що викликають кишковий кок- цидіоз у кроликів. Кокцидії розташовані в клубовій та товстій кишці. Часто кокцидіоз може бути діагностований після загибелі тварини. Типові симптоми це метеоризм кишечнику, відсутність апетиту, швидка втрата ваги, іноді спостерігається діарея. Причина загибелі тварин це інтоксикація організму та асфіксія (Dawod et al., 2022). різька, Донецька, Харківська та Сумська. Під час прове- дення досліджень було враховано такі аспекти: методи утримання кролів, характеристики приміщень та показ- ники санітарно-гігієнічної обстановки. Загалом було проаналізовано 20 ферм, де тримають кролів різних порід та вікових груп. З метою встановлення діагнозу еймеріозу були проведені лабораторні аналізи екскрементів кролів за методом Фюллеборна. Кількість ооцист еймерій на грам екскрементів (індекс OPG) визна- чалася згідно з методикою, запропонованою у камері Мак- мастера (Sadhukhan, S.K. (2022), і види Eimeria були іден- тифіковані за допомогою аналізу морфологічних критеріїв. Серія «Ветеринарна медицина», випуск 3 (62), 2023 Вісник Сумського національного аграрного університету Серія «Ветеринарна медицина», випуск 3 (62), 2023 Таблиця 2 Таблиця 2 Рівень інвазії еймеріями кролів у фермерських господарствах України при утриманні у металевих клітках, n=15 Господарства Пора року Кількість ооцист еймерій у п.з. мікроскопу EI, % эймериями 1 Осінь-зима 23 ± 1,5 29 Весна-літо 15±1,2 19 2 Осінь-зима 30±3,15 38 Весна-літо 14±0,8 17 3 Осінь-зима 12±5,5 15 Весна-літо 9±0,5 11 4 Осінь-зима 12±1,2 15 Весна-літо 7±2,5 9 5 Осінь-зима 30±0,4 37 Весна-літо 6±3,4 7 6 Осінь-зима 25±0,5 31 Весна-літо 8±3,5 10 7 Осінь-зима 13±3,0 16 Весна-літо 5±2,0 6 8 Осінь-зима 34±2,4 42 Весна-літо 14±1,5 17 9 Осінь-зима 25±3,2 31 Весна-літо 10±2,0 12 10 Осінь-зима 20±1,8 25 Весна-літо 7±0,5 9 Екстенсивність інвазії – EI Рівень інвазії еймеріями кролів у фермерських господарствах України при утриманні у металевих клітках, n=15 Екстенсивність інвазії – EI всієї групи кролів в клітці. Також суттєвим недоліком є матеріал, з якого виконані клітки – дерево. Дерево дуже пористий матеріал, який може накопичувати вологу, яйця гельмінтів, ооцисти еймерій та мікроорганізми. Прово- дити дезінфекцію та дезінвазію в таких клітках складно, так як знезараження дерева відбувається тільки на його поверхні, не проникаючи вглиб матеріалу. Це дає мож- ливість розмноженню в порах деревини мікроорганізмів та споруляції ооцист еймерій. У кожній клітці може бути різна кількість кролів від восьми до десяти. Зразки фека- лій для дослідження відбирали від кролів різних вікових груп (табл. 3). а мінімальна – 12±1,2 в п.з. мікроскопу при EI = 15 %. Отримані результати пов’язані із погіршенням мікро- клімату у приміщеннях, а саме – підвищенні вологості, погіршенні вентиляції та інсоляції. У весняно-літній період року рівень інвазії на еймеріоз зменшувався, і коливався в межах від максимального – 15±1,2 (EI = 19 %) , до мінімального – 5±2,0 (EI = 6 %). За результатами обстежень фермерських господарств із клітковим спосо- бом утримання кролів можна стверджувати, що рівень захворюваності кролів на еймеріоз був у межах допусти- мих норм, і не перевищував 42 %. Утримання кролів у дерев’яних клітках приватних господарств. У приватних присадибних господарствах кролі утримуються у дерев’яних клітках на глибокій під- стилці. Температура в клітках не регулюється і залежить від пори року, вентиляція природня. Стіни та підлога клі- ток суцільні дерев’яні, деякі елементи кліток можуть бути виконані з металевої сітки. Проблемою утримання кро- лів на дерев’яній підлозі з глибокою підстилкою є нако- пичення великої кількості фекальних мас, які кролики можуть поїдати. Таким чином відбувається інвазування Проведеними дослідженнями встановлено, що най- більший пік інвазії кролів еймеріозом був у осінньо-зимо- вий період. Супрун Юлія Олександрівна Вісник Сумського національного аграрного університету 119 Серія «Ветеринарна медицина», випуск 3 (62), 2023 Дані, отримані в результаті експерименту та пред- ставлені у таблиці 1, вказують на найвищу поширеність таких видів еймерій: Eimeria magna (25-50%), Eimeria Іntestinalis (25-50%), Eimeria perforans (до 25%), Eimeria irresidua (50-75%), Eimeria piriforms (25-50%) та Eimeria media (50-75%) (див. рис. 1-6). У фермерських та приватних домашніх господар- ствах завжди спостерігалася комбінована інвазія. Однак, відсоток випадків захворювання на кокцидіоз вияв- лявся вищим у приватних особистих господарствах, де кількість кролів може сягати 100-200 голів залежно від сезону. Це може бути пов'язано з методами утримання Рис. 1. Eimeria perforans Рис. 2. Eimeria magna Рис. 3. Eimeria media Рис. 4. Eimeria irresidua Рис. 5. Eimeria piriforms Рис. 6. Eimeria Іntestinalis Рис. 1. Eimeria perforans Рис. 2. Eimeria magna Рис. 2. Eimeria magna Рис. 1. Eimeria perforans Рис. 4. Eimeria irresidua Рис. 3. Eimeria media Рис. 3. Eimeria media Рис. 4. Eimeria irresidua Рис. 6. Eimeria Іntestinalis Рис. 5. Eimeria piriforms Рис. 5. Eimeria piriforms Рис. 6. Eimeria Іntestinalis Рис. 5. Eimeria piriforms кролів та станом санітарно-гігієнічних умов в приміщен- нях. на металевих клітках та іншому обладнанні можуть затримуватись ооцисти кокцидій. Кролі мають особли- вості періодично облизувати навколишні предмети і одне одного, таким чином відбувається перезараження тварин у групі. У кожній клітці утримується до восьми тварин. Як правило всі тварини одного віку. Але перед посадкою в одну групу їх беруть з різних кліток від матері і ділять на самців та самок. Таким чином формуються групи. Тому групи отримуємо змішані з різним ступенем інвазії. У приміщеннях-маточниках кролі утримуються у металевих клітках у один ярус. Поїлки ніпельні, годівниці бункерного типу, до яких доступ вільний. У клітках одна матка з кроленятами. Освітлення у приміщенні штучне. Вентиляція примусова механічна приплинно-витяжного Кліткове утримання кролів у фермерських госпо- дарствах. Приміщення в яких утримуються кролі двох типів літні відкриті та закриті маточники цегляні з підігрі- вом. Відкриті клітки у три яруси для утримання у теплий період року (восени, влітку та навесні) виконані з мета- левої сітки. Вентиляція в таких клітках відбувається природнім шляхом, температура змінюється залежно від навколишнього середовища 15-22  ºС. Основною проблемою такого способу утримання є підтримання санітарного стану кліток. Не зважаючи на те, що підлога виконана із сітки і кролі не можуть їсти з підлоги, зара- ження може відбуватись через їжу та воду. Також навіть Вісник Сумського національного аграрного університету Серія «Ветеринарна медицина», випуск 3 (62), 2023 120 типу. Вісник Сумського національного аграрного університету Серія «Ветеринарна медицина», випуск 3 (62), 2023 Супрун Юлія Олександрівна Температура у приміщенні взимку 17-19 ºС, а влітку 23-25 ºС. В результаті проведеного експерименту у фермер- ських господарствах за кліткового утримання встанов- лено, що екстенсивність інвазії кролів еймеріями була в межах 6-42 % і змінювалась залежно від пори року. Основний пік захворюваності на еймеріоз кролів спо- стерігали у осінньо-зимовий період. Доведено, що мак- симальна кількість ооцист кокцидій у фекальних масах кролів в холодну пору року складала 34±2,4 (EI = 42 %), У фермерських господарствах проводиться регу- лярне механічне чищення кліток від кролячого посліду. Дезінфекція відбувається за допомогою мийного при- ладу Керхер тільки під час переведення кролів з одної вікової групи в іншу. Зразки фекалій для дослідження відбирали від кролів різних вікових груп (табл. 2). Таблиця 2 Це пов’язано із зменшенням сонячної актив- ності та накопиченням калових мас у клітках. При низьких температурах відбувається примерзання посліду до клі- ток, що ускладнює процес механічної очистки та дезінва- зії кліток. Максимальна кількість кокцидій у фекальних масах кролів в холодну пору року складала 80±5,4 (EI = 100 %), а мінімальна – 45±3,8 в п.з. мікроскопу при EI Вісник Сумського національного аграрного університету Серія «Ветеринарна медицина», випуск 3 (62), 2023 121 Таблиця 3 Таблиця 3 Рівень інвазії еймеріями кролів у приватних господарствах України при утриманні у дерев’яних клітках та на підлозі, n=15 Господарства Пора року Кількість ооцист еймерій у п.з. мікроскопу EI, % эймериями 11 Осінь-зима 50 ± 4,3 63 Весна-літо 46±2,5 58 12 Осінь-зима 65±2,83 81 Весна-літо 34±1,5 43 13 Осінь-зима 72±4,5 90 Весна-літо 56±2,4 70 14 Осінь-зима 62±3,2 78 Весна-літо 28±3,3 35 15 Осінь-зима 80±5,4 100 Весна-літо 42±2,8 53 16 Осінь-зима 76±4,5 95 Весна-літо 48±3,5 60 17 Осінь-зима 56±4,7 70 Весна-літо 23±2,6 29 18 Осінь-зима 45±3,8 56 Весна-літо 24±4,4 30 19 Осінь-зима 67±5,2 84 Весна-літо 43±3,0 54 20 Осінь-зима 63±1,25 80 Весна-літо 32±1,9 40 Екстенсивність інвазії – EI Рівень інвазії еймеріями кролів у приватних господарствах України при утриманні у дерев’яних клітках та на підлозі, n=15 Екстенсивність інвазії – EI В господарствах, де металеві клітки є преобладними, максимальний відсоток екстенсивності інвазії становив 42% у період осінньо-зимового сезону. В той же час, в господарствах з дерев'яними клітками та суцільним підстиланням спостерігався високий рівень, досягаючи 100% у весінньо-зимовий період. = 56 %. У весняно-літню пору року рівень інвазії значно зменшувався, і коливався в межах від максимального – 56±2,4 (EI = 70 %), до мінімального – 23±2,6 (EI = 29 %). В результаті проведених обстежень приватних господар- ствах України при утриманні кролів у дерев’яних клітках та на суцільній підлозі рівень захворюваності на ейме- ріоз складав 100 % у осінньо-зимовий період. При мінімальних значеннях, що становили 6% у фер- мах з металевими клітками проти 29% в господарствах з дерев'яними клітками, відображалась велика контраст- ність у весняно-літній період. Динамка екстенсивності інвазії у кролів кокцидіозом за різних умов утримання представлені на рис. 7-8. На графіках, представлених на рисунках 7 та 8, ілюструється зрозуміло виражена різниця в відсотках екстенсивності інвазії в господарствах, де використову- ються металеві (від 1 до 10) та дерев'яні (від 11 до 20) клітки. Обговорення. Виконано спостереження за пошире- ністю еймеріозу на двадцяти господарствах, де утриму- ють кролів, у чотирьох регіонах України. Вісник Сумського національного аграрного університету Таблиця 2 Зразки фекалій, зібрані від тварин, були піддані аналізу для визначення 0 5 10 15 20 25 30 35 40 45 1 2 3 4 5 6 7 8 9 10 Осінь-зима Весна-літо 0 20 40 60 80 100 11 12 13 14 15 16 17 18 19 20 Осінь-зима Весна-літо Рис.7. % Екстенсивності інвазії в господарствах з металевими клітками Рис.8. % Екстенсивності інвазії в господарствах з дерев’яними клітками 0 5 10 15 20 25 30 35 40 45 1 2 3 4 5 6 7 8 9 10 Осінь-зима Весна-літо 0 20 40 60 80 100 11 12 13 14 15 16 17 18 19 20 Осінь-зима Весна-літо Рис.8. % Екстенсивності інвазії в господарствах з дерев’яними клітками Рис.7. % Екстенсивності інвазії в господарствах з металевими клітками Рис.8. % Екстенсивності інвазії в господарствах з дерев’яними клітками 122 кількості ооцист Eimeria. Після проведення мікроскопічних досліджень було встановлено, що найвища поширеність спостерігається у відношенні видів Eimeria perforans (до 25%), Eimeria Іntestinalis (25-50%), Eimeria media (50-75%), Eimeria irresidua (50-75%), Eimeria piriforms (25-50%) та Eimeria magna (25-50%) (Silva et al., 2015). Залежно від інтенсивності інвазії та кліматичних умов рівень захворю- ваності може варіюватися (Sioutas et al., 2021). але дає вірогідне уявлення про рівень інвазії та видо- вий склад кокцидій у кролівницьких господарствах України. Перспективи подальших досліджень. Дослідження інтенсивності інвазування кролів на еймеріоз в залежно- сті від методів лікування та схеми профілактики. Висновки. Результати, які були отримані, свідчать про те, що у кролівницьких господарствах фермерського та приватного напрямку найчастіше відбуваються інва- зії такими видами еймерій, як E. Magna, E. irresidua, E. media, E. іntestinalis, E. piriforms, E. perforans. Практичні дослідження підтверджують, що утримання кролів у металевих клітках за дотримання санітарно-гігієнічних норм та вчасна дезінвазія сприяють зниженню рівня випадків захворювань кролів еймеріозом. Проведене дослідження дає уяву про рівень ураже- ності крупних фермерських господарств 25-50 % та при- ватних 75-100 % . Також має значення концентрація пого- лів’я, система утримання кролів на металевих сітчастих підлогах та на суцільних дерев’яних (Xie et al., 2021). Дезінфікуючі засоби, як профілактика призвели до зменшення побічних ефектів, спричинених Eimeria spp. шляхом зменшення кількості фекальних ооцист (Sierra- Galicia et al., 2022; Thompson Burdine et al., 2021). Практична цінність проведених дослідів полягає у визначенні видового складу кокцидій та рівня інва- зування еймеріозом у кролівницьких господарствах України за різних способах утримання. Обмеження дослідження. Обмеження досліджень полягає у недостатній кількості охоплених господарств, Бібліографічні посилання: Prevention and Control of Parasitic Zoonoses. In: Parija, S.C., Chaudhury, A. (eds) Textbook of Parasitic Zoonoses. Microbial Zoonoses. Springer, Singapore. 83-90. https://doi.org/10.1007/978-981-16-7204-0_9 8. Saeed, Z., & Alkheraije, K. A. (2023). Botanicals: A promising approach for controlling cecal coccidiosis in poultry. Frontiers in veterinary science, 10, 1157633. https://doi.org/10.3389/fvets.2023.1157633 y p g 9. Sierra-Galicia, M. I., Rodríguez-de Lara, R., Orzuna-Orzuna, J. F., Lara-Bueno, A., García-Muñiz, J. G., Fallas-López, M., & Hernández-García, P. A. (2022). Supplying Bee Pollen and Propolis to Growing Rabbits: Effects on Growth Performance, Blood Metabolites, and Meat Quality. Life (Basel, Switzerland), 12(12), 1987. https://doi.org/10.3390/life12121987 9. Sierra-Galicia, M. I., Rodríguez-de Lara, R., Orzuna-Orzuna, J. F., Lara-Bueno, A., García-Muñiz, J. G., Fallas-López, M., & Hernández-García, P. A. (2022). Supplying Bee Pollen and Propolis to Growing Rabbits: Effects on Growth Performance, Blood Metabolites, and Meat Quality. Life (Basel, Switzerland), 12(12), 1987. https://doi.org/10.3390/life12121987 y ( ) ( ) p g 10. Silva, S. M., Ferreira, C., Paupério, J., Silva, R. M., Alves, P. C., & Lemos, A. (2015). Coccidiosis in European rabbit (Oryctolagus cuniculus algirus) populations in the Iberian Peninsula. Acta parasitologica, 60(2), 350–355. https://doi. org/10.1515/ap-2015-0049 10. Silva, S. M., Ferreira, C., Paupério, J., Silva, R. M., Alves, P. C., & Lemos, A. (2015). Coccidiosis in European rabbit (Oryctolagus cuniculus algirus) populations in the Iberian Peninsula. Acta parasitologica, 60(2), 350–355. https://doi. org/10.1515/ap-2015-0049 11. Sinha, S., Kaur, U., Sehgal, R. (2022). Diagnosis of Parasitic Zoonoses. In: Parija, S.C., Chaudhury, A. (eds) Text- book of Parasitic Zoonoses. Microbial Zoonoses. Springer, Singapore. 59-74. https://doi.org/10.1007/978-981-16-7204-0_7 12 Si G E l K Vl h A & P d l E (2021) D h D Mi d I f i i h P 11. Sinha, S., Kaur, U., Sehgal, R. (2022). Diagnosis of Parasitic Zoonoses. In: Parija, S.C., Chaudhury, A. (eds) Text- book of Parasitic Zoonoses. Microbial Zoonoses. Springer, Singapore. 59-74. https://doi.org/10.1007/978-981-16-7204-0_7 12 Si t G E l K Vl h A & P d l E (2021) D th D t Mi d I f ti ith P 11. Sinha, S., Kaur, U., Sehgal, R. (2022). Diagnosis of Parasitic Zoonoses. In: Parija, S.C., Chaudhury, A. (eds) Text- book of Parasitic Zoonoses. Microbial Zoonoses. Springer, Singapore. 59-74. https://doi.org/10.1007/978-981-16-7204-0_7 12. Sioutas, G., Evangelou, K., Vlachavas, A., & Papadopoulos, E. (2021). Deaths Due to Mixed Infections with Pas- salurus ambiguus Eimeria spp and Cyniclomyces guttulatus in an Industrial Rabbit Farm in Greece Pathogens (Basel book of Parasitic Zoonoses. Microbial Zoonoses. Бібліографічні посилання: р ф 1. 6 Bochyńska, D., Lloyd, S., Restif, O., & Hughes, K. (2022). Eimeria stiedae causes most of the white-spotted liver lesions in wild European rabbits in Cambridgeshire, United Kingdom. Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc, 34(2), 199–205. https://doi. org/10.1177/10406387211066923 р ф 1. 6 Bochyńska, D., Lloyd, S., Restif, O., & Hughes, K. (2022). Eimeria stiedae causes most of the white-spotted liver lesions in wild European rabbits in Cambridgeshire, United Kingdom. Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc, 34(2), 199–205. https://doi. org/10.1177/10406387211066923 1. 6 Bochyńska, D., Lloyd, S., Restif, O., & Hughes, K. (2022). Eimeria stiedae causes most of the white-spotted liver lesions in wild European rabbits in Cambridgeshire, United Kingdom. Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc, 34(2), 199–205. https://doi. org/10.1177/10406387211066923 g 2. Athanasiou, L. V., Tsokana, C. N., Doukas, D., Kantere, M. C., Katsoulos, P. D., Papakonstantinou, G. I., Katsogi- annou, E. G., & Dedousi, A. (2023). Hepatic Coccidiosis in Wild Rabbits in Greece: Parasite Detection on Liver Imprints and the Associated Biochemical Profile. Veterinary sciences, 10(4), 248. https://doi.org/10.3390/vetsci10040248 2. Athanasiou, L. V., Tsokana, C. N., Doukas, D., Kantere, M. C., Katsoulos, P. D., Papakonstantinou, G. I., Katsogi- annou, E. G., & Dedousi, A. (2023). Hepatic Coccidiosis in Wild Rabbits in Greece: Parasite Detection on Liver Imprints and the Associated Biochemical Profile. Veterinary sciences, 10(4), 248. https://doi.org/10.3390/vetsci10040248 3 D d A F h ll S El S di H R H d M A O N Ab h ib N A i A Sh h A A & i y ( ) p g 3. Dawod, A., Fathalla, S., El-Seedi, H. R., Hammad, M. A., Osman, N., Abosheriba, N., Anis, A., Shehata, A. A., & Elkhatam, A. (2022). Efficacy of Ficus sycomorus (Sycamore Fig) Extract on Intestinal Coccidiosis in Experimentally Infected Rabbits. Life (Basel, Switzerland), 12(6), 917. https://doi.org/10.3390/life12060917 i y ( ) g 3. Dawod, A., Fathalla, S., El-Seedi, H. R., Hammad, M. A., Osman, N., Abosheriba, N., Anis, A., Shehata, A. A., & Elkhatam, A. (2022). Efficacy of Ficus sycomorus (Sycamore Fig) Extract on Intestinal Coccidiosis in Experimentally Infected Rabbits. Life (Basel, Switzerland), 12(6), 917. https://doi.org/10.3390/life12060917 ( , ), ( ), p g 4. El-Ashram, S. A., Aboelhadid, S. M., Abdel-Kafy, E. M., Hashem, S. Бібліографічні посилання: A., Mahrous, L. N., Farghly, E. M., Moawad, U. K., & Kamel, A. A. (2019). Prophylactic and Therapeutic Efficacy of Prebiotic Supplementation against Intestinal Coccidiosis in Rabbits. Animals : an open access journal from MDPI, 9(11), 965. https://doi.org/10.3390/ani9110965 4. El-Ashram, S. A., Aboelhadid, S. M., Abdel-Kafy, E. M., Hashem, S. A., Mahrous, L. N., Farghly, E. M., Moawad, U. K., & Kamel, A. A. (2019). Prophylactic and Therapeutic Efficacy of Prebiotic Supplementation against Intestinal Coccidiosis in Rabbits. Animals : an open access journal from MDPI, 9(11), 965. https://doi.org/10.3390/ani9110965 p j ( ) p g 5. El-Shall, N. A., Abd El-Hack, M. E., Albaqami, N. M., Khafaga, A. F., Taha, A. E., Swelum, A. A., El-Saadony, M. T., Salem, H. M., El-Tahan, A. M., AbuQamar, S. F., El-Tarabily, K. A., & Elbestawy, A. R. (2022). Phytochemical control of poul- try coccidiosis: a review. Poultry science, 101(1), 101542. https://doi.org/10.1016/j.psj.2021.101542fi p j ( ) p g 5. El-Shall, N. A., Abd El-Hack, M. E., Albaqami, N. M., Khafaga, A. F., Taha, A. E., Swelum, A. A., El-Saadony, M. T., Salem, H. M., El-Tahan, A. M., AbuQamar, S. F., El-Tarabily, K. A., & Elbestawy, A. R. (2022). Phytochemical control of poul- try coccidiosis: a review. Poultry science, 101(1), 101542. https://doi.org/10.1016/j.psj.2021.101542fi y y , ( ), p g j p j 6. Ogolla, K. O., Gathumbi, P. K., Waruiru, R. M., Okumu, P. O., Chebet, J., & Kitala, P. M. (2018). Efficacy of Sulphachlo- ropyrazine, Amprolium Hydrochloride, Trimethoprim-Sulphamethoxazole, and Diclazuril against Experimental and Natural Rabbit Coccidiosis. Journal of veterinary medicine, 2018, 5402469. https://doi.org/10.1155/2018/5402469 y y ( ) p g j p j 6. Ogolla, K. O., Gathumbi, P. K., Waruiru, R. M., Okumu, P. O., Chebet, J., & Kitala, P. M. (2018). Efficacy of Sulphachlo- ropyrazine, Amprolium Hydrochloride, Trimethoprim-Sulphamethoxazole, and Diclazuril against Experimental and Natural Rabbit Coccidiosis. Journal of veterinary medicine, 2018, 5402469. https://doi.org/10.1155/2018/5402469 y , , p g 7. Sadhukhan, S.K. (2022). Prevention and Control of Parasitic Zoonoses. In: Parija, S.C., Chaudhury, A. (eds) Textbook of Parasitic Zoonoses. Microbial Zoonoses. Springer, Singapore. 83-90. https://doi.org/10.1007/978-981-16-7204-0_9 8. Saeed, Z., & Alkheraije, K. A. (2023). Botanicals: A promising approach for controlling cecal coccidiosis in poultry. y , , p g 7. Sadhukhan, S.K. (2022). Prevention and Control of Parasitic Zoonoses. In: Parija, S.C., Chaudhury, A. (eds) Textbook of Parasitic Zoonoses. Microbial Zoonoses. Springer, Singapore. 83-90. https://doi.org/10.1007/978-981-16-7204-0_9 y p g 7. Sadhukhan, S.K. (2022). p g g p p g 8. Saeed, Z., & Alkheraije, K. A. (2023). Botanicals: A promising approach for controlling Frontiers in veterinary science, 10, 1157633. https://doi.org/10.3389/fvets.2023.1157633 Вісник Сумського національного аграрного університету Серія «Ветеринарна медицина», випуск 3 (62), 2023 y , , p g 7. Sadhukhan, S.K. (2022). Prevention and Control of Parasitic Zoonoses. In: Parija, S.C., Chaudhury, A. (eds) Textbook of Parasitic Zoonoses. Microbial Zoonoses. Springer, Singapore. 83-90. https://doi.org/10.1007/978-981-16-7204-0_9 Бібліографічні посилання: О., PhD student, Sumy National Agrarian University, Sumy, Ukrainef , , y g y, y, y of the prevalence and methods of detection of eimeriosis among rabbits depending on different me p , , y g y, y, Study of the prevalence and methods of detection of eimeriosis among rabbits depending on diffe keeping p , , y g y, y, Study of the prevalence and methods of detection of eimeriosis among rabbits depending on different methods of keeping p g One of the key difficulties in the process of raising rabbits is eimeriosis, regardless of the methods of keeping them. This disease affects animals of all age groups, leading to a decrease in weight gain, deterioration of the efficiency of assimilation of feed, increased morbidity. , y The purpose of the study was to determine the prevalence and methods of detection of eimeriosis among rabbits, depending on different methods of keeping, with the aim of improving strategies for combating this disease and improving quarantine methods.f q During the period from 2019 to 2021, research was conducted in farms with different power level Zaporizhzhya, Donetsk, Kharkiv and Sumy. In total, 20 farms where rabbits of different breeds were kept During the period from 2019 to 2021, research was conducted in farms with different power levels in four regions: Zaporizhzhya, Donetsk, Kharkiv and Sumy. In total, 20 farms where rabbits of different breeds were kept were surveyed. In farms and private rabbit farms, E. intestinalis, E. magna, E. media, E. piriforms, E. perforans, E. irresidua were isolated. It was proved that in the winter period the level of oocysts was from 12±1.2 to 34±2.4 in p.z. microscope In the summer period, the level of infestation decreased and ranged from a maximum of 15±1.2 (EI = 19%) to a minimum of 5±2.0 (EI = 6%). The study confirmed that in conditions of keeping in metal cages in farms, with compliance with sanitary and hygienic norms and regular disinfection of premises, the level of infestation was from 15% to 42% in the winter period and from 6% to 19% in the summer period. In an analysis of data obtained from private farms where rabbits are kept in wooden cages with deep bedding, it was found that the infestation rate was between 56% and 100% during the cold period and between 29% and 70% during the warm period. Вісник Сумського національного аграрного університету Вісник Сумського національного аграрного університету Серія «Ветеринарна медицина», випуск 3 (62), 2023 Бібліографічні посилання: Springer, Singapore. 59-74. https://doi.org/10.1007/978-981-16-7204-0_7 12. Sioutas, G., Evangelou, K., Vlachavas, A., & Papadopoulos, E. (2021). Deaths Due to Mixed Infections with Pas- salurus ambiguus, Eimeria spp. and Cyniclomyces guttulatus in an Industrial Rabbit Farm in Greece. Pathogens (Basel, Switzerland), 10(6), 756. https://doi.org/10.3390/pathogens10060756 13 S & S G (2021) fl 12. Sioutas, G., Evangelou, K., Vlachavas, A., & Papadopoulos, E. (2021). Deaths Due to Mixed Infections with Pas- salurus ambiguus, Eimeria spp. and Cyniclomyces guttulatus in an Industrial Rabbit Farm in Greece. Pathogens (Basel, Switzerland), 10(6), 756. https://doi.org/10.3390/pathogens10060756 l ), ( ), p g p g 13. Thompson Burdine, J., Thorne, S., & Sandhu, G. (2021). Interpretive description: A flexible qua for medical education research. Medical education, 55(3), 336–343. https://doi.org/10.1111/medu.14380 ), p g p g on Burdine, J., Thorne, S., & Sandhu, G. (2021). Interpretive description: A flexible qualitative methodology tion research. Medical education, 55(3), 336–343. https://doi.org/10.1111/medu.14380 ( ) p g 14. Xiao, J., Zheng, R., Bai, X., Pu, J., Chen, H., Gu, X., Xie, Y., He, R., Xu, J., Jing, B., Peng, X., & Yang, G. (2022). Preliminary evaluation of the protective effects of recombinant AMA1 and IMP1 against Eimeria stiedae infection in rabbits. Parasites & vectors, 15(1), 400. https://doi.org/10.1186/s13071-022-05492-4 ( ) p g 14. Xiao, J., Zheng, R., Bai, X., Pu, J., Chen, H., Gu, X., Xie, Y., He, R., Xu, J., Jing, B., Peng, X., & Yang, G. (2022). Preliminary evaluation of the protective effects of recombinant AMA1 and IMP1 against Eimeria stiedae infection in rabbits. Parasites & vectors, 15(1), 400. https://doi.org/10.1186/s13071-022-05492-4 ( ) p g 15. Xie, Y., Xiao, J., Zhou, X., Gu, X., He, R., Xu, J., Jing, B., Peng, X., & Yang, G. (2021). Global transcriptome landscape of the rabbit protozoan parasite Eimeria stiedae. Parasites & vectors, 14(1), 308. https://doi.org/10.1186/ s13071-021-04811-5 15. Xie, Y., Xiao, J., Zhou, X., Gu, X., He, R., Xu, J., Jing, B., Peng, X., & Yang, G. (2021). Global transcriptome landscape of the rabbit protozoan parasite Eimeria stiedae. Parasites & vectors, 14(1), 308. https://doi.org/10.1186/ s13071-021-04811-5 123 Серія «Ветеринарна медицина», випуск 3 (62), 2023 Серія «Ветеринарна медицина», випуск 3 (62), 2023 hkromada O. I., Doctor of Veterinary Sciences, Professor, Sumy National Agrarian University, Sumy, Ukrain , y y g y y Suprun Yu. Бібліографічні посилання: g p The use of metal cages for keeping rabbits in compliance with sanitary and hygienic requirements and time lps to reduce the prevalence of parasitic infections. The use of metal cages for keeping rabbits in compliance with sanitary and hygienic requirements and time lps to reduce the prevalence of parasitic infections. K d bbit i i i bi l i l l f i i i t it f i f t ti f k i bbit to reduce the prevalence of parasitic infections. ey words: rabbit eimeriosis, biological cycle of eimeria, intensity of infestation, ways of keeping rabbits. p p p Key words: rabbit eimeriosis, biological cycle of eimeria, intensity of infestation, ways of keeping rabbits. p p p Key words: rabbit eimeriosis, biological cycle of eim 124
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https://ped-rheum.biomedcentral.com/counter/pdf/10.1186/1546-0096-13-S1-O74
English
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A functional inflammasome activation assaydifferentiates patients with pathogenic NLRP3mutations and symptomatic patients with lowpenetrance variants
Pediatric rheumatology online journal
2,015
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500
Question confirmed pathogenic CAPS mutations compared to low penetrance NLRP3 variants and controls. IL-1b secre- tion in CAPS patients correlated with disease severity. TNF-a secretion was significantly reduced in CAPS patients and NLRP3 variants when compared to healthy controls after 4h of stimulation. The cryopyrin-associated periodic syndromes (CAPS) are characterized by recurrent episodes of systemic inflam- mation. CAPS is caused by mutations in the NLRP3 gene encoding cryopyrin, an important component of the NLRP3 inflammasome that activates caspase-1 resulting in inflammation by excessive production of IL-1b and others. Besides confirmed pathogenic NLRP3 mutations, patients with CAPS-like symptoms frequently show low penetrance variants in NLRP3. The disease relevance of these variants is inconsistent. The analysis of IL-1b in the serum did not prove to be a valid diagnostic test in these individuals. © 2015 Rieber et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http:// creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/ zero/1.0/) applies to the data made available in this article, unless otherwise stated. Conclusion This inflammasome activation assay differentiates between autoinflammation patients with confirmed pathogenic CAPS mutations and patients with low pene- trance NLRP3 variants, and points towards alternative pathophysiological mechanisms in low penetrance NLRP3 variants. Methods In this study, we investigated if an inflammasome activa- tion assay differentiates between patients with confirmed pathogenic CAPS mutations, patients with low pene- trance NLRP3 variants (V198M and Q703K) and healthy controls. The study population consisted of 17 patients with genetically proven Muckle-Wells syndrome, 11 patients with low penetrance NLRP3 variants and 15 healthy controls. Concentrations of IL-1b, IL-18, Cas- pase-1, TNF-a and IL-6 were quantified in cell culture supernatants after inflammasome stimulation with LPS and LPS + ATP for several time intervals. Published: 28 September 2015 doi:10.1186/1546-0096-13-S1-O74 Cite this article as: Rieber et al.: A functional inflammasome activation assaydifferentiates patients with pathogenic NLRP3mutations and symptomatic patients with lowpenetrance variants. Pediatric Rheumatology 2015 13(Suppl 1):O74. A functional inflammasome activation assaydifferentiates patients with pathogenic NLRP3mutations and symptomatic patients with lowpenetrance variants N Rieber*, A Gavrilov, L Hofer, A Singh, H Öz, T Endres, I Schäfer, R Handgretinger, D Hartl, J Kümmerle-Deschner From 8th International Congress of Familial Mediterranean Fever and Systemic Autoinflammatory Diseases Dresden, Germany. 30 September - 3 October 2015 © 2015 Rieber et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http:// creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/ zero/1.0/) applies to the data made available in this article, unless otherwise stated. Rieber et al. Pediatric Rheumatology 2015, 13(Suppl 1):O74 http://www.ped-rheum.com/content/13/S1/O74 Open Access Open Access Results The release of mature IL-1b, IL-18, and caspase-1 into cell culture supernatants after 4h of inflammasome sti- mulation was significantly increased in patients with Children’s hospital Tübingen, Tübingen, Germany
https://openalex.org/W2984801984
https://figshare.com/articles/journal_contribution/New_i_ent_i_-kauran_diterpene_and_antioxidant_components_from_the_seed_of_i_Ipomoea_nil_i_/10259909/1/files/18528164.pdf
English
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New <i>ent</i>-kauran diterpene and antioxidant components from the seed of <i>Ipomoea nil</i>
Natural product research
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New ent-kauran diterpene and antioxidant components from the seed of Ipomoea nil b d f aDepartment of Cosmeceutics, China Medical University, Taichung, Taiwan bChinese Medicine Research and Development Center, China Medical University Hospital, Taichung, Taiwan cChinese Medicine Research Center, China Medical University, Taichung, Taiwan dGraduate Institute of Integrated Medicine, China Medical University, Taichung, Taiwan eProteomics Core Laboratory, Department of Medical Research, China Medical University Hospital, Taichung, Taiwan fDepartment of Chinese Pharmaceutical Sciences and Chinese Medicine Resources, China Medical University, Taichung, Taiwan fDepartment of Chinese Pharmaceutical Sciences and Chinese Medicine Resources, China Medical University, Taichung, Taiwan CONTACT Chia-Lin Lee chlilee@mail.cmu.edu.tw CONTACT Chia-Lin Lee chlilee@mail.cmu.edu.tw ABSTRACT One new ent-kauran diterpene, 7β,16β,17-trihydroxy ent-kauran 19-(6β)-olide (1), along with eight known compounds were isolated from the seed of Ipomoea nil. Isolates caffeoylquinic acid derivatives 5−9 were found for the first time in this species. All structures were identified from various spectroscopic data. trans-Caffeic acid 3, phenylpropanoid 4, and caffeoylquinic acid derivatives 5−9 could inhibit ROS generations induced in human keratinocyte HaCaT cells with IC50 values of 0.94−28.40 μM. Compounds 3 and 5−9 also had DPPH free radical scavenging properties (IC50 values, 14.86−68.27 μM), however, isolate 4 did not show inhibition effect. Generally, I. nil and its secondary metabolites 3−9 could be further applied for oxidative stress damage resulted in skin disorders. KEYWORDS: Ipomoea nil; Convolvulaceae; ent-Kauran diterpenoid; Anti-ROS; Anti-DPPH KEYWORDS: Ipomoea nil; Convolvulaceae; ent-Kauran diterpenoid; Anti-ROS; Anti-DPPH S1 Figure S1. 1H NMR (500 MHz, CD3OD) of compound 1…………………..………………………......S3 Figure S2. 13C NMR (125 MHz, CD3OD) of compound 1……………………………………………S3 Figure S3. DEPT135 NMR (125 MHz, CD3OD) of compound 1.…………………………….………..S4 Figure S4. HSQC NMR (500 MHz, CD3OD) of compound 1….……………………………………….S4 Figure S5. COSY NMR (500 MHz, CD3OD) of compound 1…………………………..…..…………..S5 Figure S6. HMBC NMR (500 MHz, CD3OD) of compound 1….………………………….…………S5 Figure S7. NOESY NMR (500 MHz, CD3OD) of compound 1..…………………………………......S6 Figure S8. IR spectrum of compound 1..…………………………………….……………………….....S6 Figure S9. High ESI-MS spectrum of compound 1.………………………………………………….....S7 Figure S10. Key COSY and HMBC correlations for compound 1………………………………………S7 Figure S11. Key NOESY correlations for compound 1…………………………………………………S7 Figure S12. Anti-ROS generation in HaCaT cells (A-1 to D-1) and cytotoxicity toward HaCaT (A-2 to D-2) of crude extract MPS, fractions MPSH, MPSB, and MPSW, respectively…...S8 Figure S13. Anti-DPPH free radical scavenging properties of crude extract MPS, fractions MPSH, MPSB, and MPSW.………………….…………....S8 Figure S14. Cytotoxicity toward HaCaT cells of compounds 3−9.………………………………….….S9 Figure S15. Anti-ROS generation in HaCaT cells of compounds 3−9………………………………S9 Figure S16. Anti-DPPH free radical scavenging properties of compounds 3−9…………..……..….S10 Table S1. 1H and 13C NMR spectroscopic data (500 and 125 MHz, CD3OD) for 1……………………S10 Table S2. Antioxidant activities of crude extract, fractions, and pure compounds 3−9………………S11 S2 Figure S1. 1H NMR (500 MHz, CD3OD) of compound 1. Figure S2. 13C NMR (125 MHz, CD3OD) of compound 1. Figure S1. 1H NMR (500 MHz, CD3OD) of compound 1. Figure S1. 1H NMR (500 MHz, CD3OD) of compound 1. Figure S2. 13C NMR (125 MHz, CD3OD) of compound 1. Figure S2. 13C NMR (125 MHz, CD3OD) of compound 1. Figure S2. ABSTRACT 13C NMR (125 MHz, CD3OD) of compound 1. S3 S3 Figure S3. DEPT135 NMR (125 MHz, CD3OD) of compound 1. Figure S3. DEPT135 NMR (125 MHz, CD3OD) of compound 1. Figure S4. HSQC NMR (500 MHz, CD3OD) of compound 1. Figure S4. HSQC NMR (500 MHz, CD3OD) of compound 1. S4 S4 Figure S5. COSY NMR (500 MHz, CD3OD) of compound 1. Figure S5. COSY NMR (500 MHz, CD3OD) of compound 1. Figure S6. HMBC NMR (500 MHz, CD3OD) of compound 1. Figure S5. COSY NMR (500 MHz, CD3OD) of compound 1. Figure S5. COSY NMR (500 MHz, CD3OD) of compound 1. Figure S6. HMBC NMR (500 MHz, CD3OD) of compound 1. Figure S6. HMBC NMR (500 MHz, CD3OD) of compound 1. S5 S5 Figure S7. NOESY NMR (500 MHz, CD3OD) of compound 1. S6 Figure S7. NOESY NMR (500 MHz, CD3OD) of compound 1. Figure S8. IR spectrum of compound 1. Figure S7. NOESY NMR (500 MHz, CD3OD) of compound 1. Figure S8. IR spectrum of compound 1. Figure S8. IR spectrum of compound 1. S6 S6 158.8431 369.2394 389.1728 453.1664 MPSB3354112_350.d: +MS, 0.3min #17 0.0 0.5 1.0 1.5 7 x10 Intens. 100 200 300 400 500 600 m/z Figure S9. High ESI-MS spectrum of compound 1. Figure S10. Key COSY and HMBC correlations for compound 1. 158.8431 369.2394 389.1728 453.1664 MPSB3354112_350.d: +MS, 0.3min #17 0.0 0.5 1.0 1.5 7 x10 Intens. 100 200 300 400 500 600 m/z Figure S9. High ESI-MS spectrum of compound 1. 158.8431 369.2394 389.1728 453.1664 MPSB3354112_350.d: +MS, 0.3min #17 0.0 0.5 1.0 1.5 7 x10 Intens. 100 200 300 400 500 600 m/z Figure S9. High ESI-MS spectrum of compound 1. Figure S10. Key COSY and HMBC correlations for compound 1. Figure S10. Key COSY and HMBC correlations for compound 1. Figure S11. Key NOESY correlations for compound 1. Figure S11. Key NOESY correlations for compound 1. S7 S7 Figure S12. Anti-ROS generation in HaCaT cells (A-1 to D-1) and cytotoxicity toward HaCaT (A-2 to D-2) of crude extract MPS, fractions MPSH, MPSB, and MPSW, respectively. Figure S12. Anti-ROS generation in HaCaT cells (A-1 to D-1) and cytotoxicity toward HaCaT (A-2 to D-2) of crude extract MPS, fractions MPSH, MPSB, and MPSW, respectively. Figure S13 Anti-DPPH free radical scavenging properties of crude extract MPS, fractions MPSH, MPSB, and MPSW. ABSTRACT Figure S13 Anti-DPPH free radical scavenging properties of crude extract MPS, fractions MPSH, MPSB, and MPSW. S8 S8 Figure S14. Cytotoxicity toward HaCaT cells of compounds 3−9. Figure S15. Anti-ROS generation in HaCaT cells of compounds 3−9. Figure S14. Cytotoxicity toward HaCaT cells of compounds 3−9. Figure S14. Cytotoxicity toward HaCaT cells of compounds 3−9. Figure S15. Anti-ROS generation in HaCaT cells of compounds 3−9. Figure S15. Anti-ROS generation in HaCaT cells of compounds 3−9. S9 S9 Figure S16. Anti-DPPH free radical scavenging properties of compounds 3−9. Figure S16. Anti-DPPH free radical scavenging properties of compounds 3−9. Table S1. 1H and 13C NMR spectroscopic data (500 and 125 MHz, CD3OD) for 1. 1 position δH (J in Hz) δC 1 0.95, m 1.80, ma 33.1 2 1.80, ma (2H) 17.8 3 1.55, ma 1.73, ma 25.0 4 42.0 5 2.34, d (11.5) 49.1 6 4.33, dd (11.5, 1.5) 79.9 7 3.78, brs 78.7 8 51.8 9 1.52, ma 55.8 10 40.5 11 1.53, ma 2.08, ma 19.2 12 1.53, ma 1.80, ma 27.7 13 2.11, m 42.3 14 1.30, dd (13.5, 5.0) 1.90, dd (13.5, 2.0) 39.6 15 1.49, d (14.5)a 1.93, d (14.5) 49.5 16 80.4 17 3.34, d (11.0) 3.42, d (11.0) 70.7 18 1.23, s 29.8 19 185.8 20 1.13, s 17.9 a Overlapped signals Table S1. 1H and 13C NMR spectroscopic data (500 and 125 MHz, CD3OD) for 1 S10 Table S2. Antioxidant activities of crude extract, fractions, and pure compounds 3−9. Crude extract and fractions IC50 (μg/mL) MPS MPSH MPSB MPSW Vit. C HaCaT-ROSa 9.18±0.66 >25 6.80±0.98 19.11±1.01 - DPPH 150.63±19.18 >500 122.21±9.50 312.63±19.42 < 7.81 Pure compound IC50 (μM) 3 4 5 6 HaCaT-ROSa 3.78±0.32 28.40±6.57 1.04±0.16 0.94±0.08 DPPH 57.24±0.59 >200 18.48±0.49 14.86±0.26 7 8 9 Vit. C HaCaT-ROSa 1.24±0.09 1.00±0.18 2.61±0.24 < 20 DPPH 17.41±1.41 18.96±1.22 68.27±1.80 26.76±2.37 a All test compounds should inhibit ROS generations induced in HaCaT without cytotoxicity toward HaCaT cells. Antioxidant activities of crude extract, fractions, and pure compounds 3−9. a All test compounds should inhibit ROS generations induced in HaCaT without cytotoxicity toward HaCaT cells. S11
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Benefits and challenges of EMR implementations in low resource settings: a state-of-the-art review
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* Correspondence: bjawhari@ualberta.ca 1Department of Medicine, Faculty of Medicine & Dentistry, University of Alberta, Clinical Sciences Building, 8440-112 St NW 5th floor, 5-112E, T6G 2B7 Edmonton, AB, Canada 2Innovative Canadians for Change, Edmonton, AB, Canada Full list of author information is available at the end of the article Benefits and challenges of EMR implementations in low resource settings: a state-of-the-art review Badeia Jawhari1,2*, Dave Ludwick3, Louanne Keenan1, David Zakus4 and Robert Hayward1 © 2016 The Author(s). Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Jawhari et al. BMC Medical Informatics and Decision Making (2016) 16:116 DOI 10.1186/s12911-016-0354-8 Jawhari et al. BMC Medical Informatics and Decision Making (2016) 16:116 DOI 10.1186/s12911-016-0354-8 Jawhari et al. BMC Medical Informatics and Decision Making (2016) 16:116 DOI 10.1186/s12911-016-0354-8 Background and classification of revealed literature, as well as analysis of the content of the selected literature. Health Information Systems (HIS), including Electronic Medical Record (EMR) systems, show promise for fa- cilitating health care improvement. Many sub-Saharan African countries recognize this opportunity and ac- tively deploy e-health technologies, including mobile health devices, electronic medical records, electronic health records, and risk surveillance systems. Despite their characterization as developing countries, some have demonstrated leadership through significant in- vestment in recent-generation health information sys- tems. However, relatively little is known about how the HIS promise can be realized in resource-constrained settings, or about the applicability of evidence arising from well-resourced settings. This review examines published reports about how EMRs have been deployed in sub-Saharan African slums, which intervention attri- butes associate with deployment success, which cat- egories of benefits and harms are observed, what forms of inquiry have been employed, and where important uncertainty remains. A starter list of search concepts reflected key elements of the review objectives. The list was modified as search cycles were conducted and new concepts emerged in re- trieved reports, yielding optimized inclusion and exclu- sion criteria (Appendix 1). These were matched to standardized Medical Subject Heading (MeSH) terms for use in database-specific search strategies (Appendix 2). Publication dates were not specified because a relative paucity of relevant studies and because the recent ap- pearance of EMRs in the settings of interest made the publication date implicit in other search criteria. Major North American (MEDLINE) and European (EMBASE) citation databases, and one specialty citation database (GLOBAL HEALTH) were searched in addition to the Cochrane database of reviews and the Cochrane controlled trial registry. A general Internet scan was conducted using the Google search engine. The “Grey literature,” including conference proceedings, theses, websites, and government reports, was explored using Google and Google Scholar. Reference lists of retrieved publications were checked for literature not found through searching. All databases were searched from in- ception through start of February 2015. A preliminary search of mainstream bibliographic da- tabases revealed few reports about experiences with EMRs in resource-limited settings. Most focused on Hu- man Immunodeficiency Virus (HIV) and Tuberculosis (TB) patient management [1–3]. Little was reported about the effects of EMRs on primary care practices or on general health outcomes in slum settings. Background Experimen- tal inquiry is rare and the published reports do not pro- vide the level of detail about methods or findings required for systematic review or meta-analytic synthesis methods. Accordingly, this review adopts a “State-of-the- Art” [4] approach; describing what has been published, how insights were derived from observation, and which issues have been explored by what method. The objective is to provide a foundation for the future application of sys- tematic review methods to an expanding literature about EMR impacts in resource-constrained settings. There were challenges minimizing false positives while avoiding false negatives associated with search strategies, possibly because key concepts were represented differently in different databases. For example, MEDLINE, GLOBAL HEALTH and the COCHRANE LIBRARY used the “Africa South of the Sahara” instead of “sub-Saharan Africa” found in EMBASE [1, 5]. Terms for digital health records (e.g., “Electronic Health Record,” “Elec- tronic Medical Record,” “Patient Health Record,” etc.) varied widely. Full-text synonym searching proved import- ant in all indexed databases, having the greatest impact on GOOGLE and GOOGLE SCHOLAR performance. p The results of optimized bibliographic searches were combined to constitute the initial “population” of 695 potentially relevant citations. Internet and grey literature searches discovered 54 additional relevant communica- tions. Of the 749 pooled bibliographic and grey literature citations, 738 referenced papers or articles possibly relevant to EMR use in resource-constrained settings. The abstracts of these were passed through more specific setting (country, practice type, intervention type) and methods (literature type, study type, process or outcome focus) filters to yield 96 papers addressing EMR imple- mentation or adoption challenges in resource-constrained parts of sub-Saharan Africa. The introduction, objectives and methods sections were reviewed to re-apply relevance and methods filters, excluding 54 more reports where EMRs were used in mainly in hospitals rather than community-based clinics. Abstract Background: The intent of this review is to discover the types of inquiry and range of objectives and outcomes addressed in studies of the impacts of Electronic Medical Record (EMR) implementations in limited resource settings in sub-Saharan Africa. Methods: A state-of-the-art review characterized relevant publications from bibliographic databases and grey literature repositories through systematic searching, concept-mapping, relevance and quality filter optimization, methods and outcomes categorization and key article analysis. Results: From an initial population of 749 domain articles published before February 2015, 32 passed context and methods filters to merit full-text analysis. Relevant literature was classified by type (e.g., secondary, primary), design (e.g., case series, intervention), focus (e.g., processes, outcomes) and context (e.g., location, organization). A conceptual framework of EMR implementation determinants (systems, people, processes, products) was developed to represent current knowledge about the effects of EMRs in resource-constrained settings and to facilitate comparisons with studies in other contexts. Discussion: This review provides an overall impression of the types and content of health informatics articles about EMR implementations in sub-Saharan Africa. Little is known about the unique effects of EMR efforts in slum settings. The available reports emphasize the complexity and impact of social considerations, outweighing product and system limitations. Summative guides and implementation toolkits were not found but could help EMR implementers Conclusion: The future of EMR implementation in sub-Saharan Africa is promising. This review reveals various examples and gaps in understanding how EMR implementations unfold in resource-constrained settings; and opportunities for new inquiry about how to improve deployments in those contexts. Keywords: Electronic medical record, Electronic health record, Implementation, Urban slum, Limited resource setting, Sub-Saharan Africa Abbreviations: EMR, Electronic medical record; HIS, Health information system; HIV, Human immunodeficiency virus; ID, Identification card; MeSH, Medical subject heading; TB, Tuberculosis © 2016 The Author(s). Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Jawhari et al. BMC Medical Informatics and Decision Making (2016) 16:116 Jawhari et al. BMC Medical Informatics and Decision Making (2016) 16:116 Page 2 of 12 Page 2 of 12 Methods The review was conducted as a step-wise process. First, a general search strategy was derived from a concept map linking question-appropriate concepts. Associated key- words were discovered from multiple search-review cycles in diverse databases. Second, specific search strategies were optimized for each source database. Third, relevance filters were developed and applied to the search results to determine the prevalence of reports addressing specific settings, interventions and outcomes of interest. Fourth, methods descriptors were devised and used to classify the relevant literature. Finally, papers that were both relevant and methodologically credible were reviewed in detail. The overview results are expressed through description Jawhari et al. BMC Medical Informatics and Decision Making (2016) 16:116 Jawhari et al. BMC Medical Informatics and Decision Making (2016) 16:116 Jawhari et al. BMC Medical Informatics and Decision Making (2016) 16:116 Page 3 of 12 Table 1 Relevance-filtered publications grouped by inquiry type Inquiry type Citations Primary 28 Case Reports 21 Implementation focus 16 Adoption focus 5 Program Descriptions 22 EMR deployment benefits, challenges and system design 22 Observational Inquiry 16 - Qualitative Inquiry 0 User perceptions 2 Patient perceptions 1 - Program evaluation 15 Data quality review 3 Appointment management 6 Workflow assessment 2 Time motion study 2 Experimental Inquiry 1 Uncontrolled trials 1 Secondary Literature 17 - Commentary and editorials 6 - Position statements and guidelines 2 - Narrative reviews 7 - Systematic reviews 2 Table 1 Relevance-filtered publications grouped by inquiry type Inquiry type Citations Primary 28 Case Reports 21 Implementation focus 16 Adoption focus 5 Program Descriptions 22 EMR deployment benefits, challenges and system design 22 Observational Inquiry 16 - Qualitative Inquiry 0 User perceptions 2 Patient perceptions 1 - Program evaluation 15 Data quality review 3 Appointment management 6 Workflow assessment 2 Time motion study 2 Experimental Inquiry 1 Uncontrolled trials 1 Secondary Literature 17 - Commentary and editorials 6 - Position statements and guidelines 2 - Narrative reviews 7 - Systematic reviews 2 A total of 32 reports remained for comprehensive full- text review. Seven proved a close fit to the review objec- tives, six about EMR implementations in Kenya and one about Cameroon experiences [6–12]. None specifically addressed EMR implementation challenges in slum set- tings. Most were published within the previous 5 years and reports published between 2000–2009 were least in- formative about EMR challenges, most referencing EMR technology new to low resource settings. Inquiry types Relevance-filtered publications were grouped by whether they reported original observations or interpreted the observations of others. The primary literature was fur- ther subdivided by the type of inquiry used to generate observations (Table 1). There were 21 case series reports, where a common intervention crossed multiple EMR implementations. Foci of reportage included paper-to-digital record transform- ation challenges [13], clinician distraction by user interfaces [14], training effects, and determinants of user acceptance [14]. One case series explored hardware and software barriers to implementation, including corrupted files and server failures [14]. implementation or in non-implementation settings. Where observational studies claimed overall user satisfaction with EMRs, the authors often did not reconcile this with their own report of user complaints respecting training burdens, loss of productivity and difficulty finding key information [19]. Many case studies shared experience-based recom- mendations about best practices, with a common theme that user involvement increases buy-in before, during and after implementation. Such buy-in is enhanced by EMR customization, sustainable funding and access to a digitally- capable workforce [14]. Implementation opportunities include, for example, loss of paper storage space and im- provements in record filing, stock control [15] and report acceptance by government or funding agencies [11, 12, 15]. One case series shared experiences with different open- source EMRs, including financial implications for groups contemplating adoption in resource-limited settings [16]. g y Program evaluations tended to focus on the quality and application of data accrued by EMRs while com- menting on operational considerations like error rates, visit duration, appointment no-shows, wait times, clinic efficiency, and fulfillment of service delivery expecta- tions [18, 19, 21, 22]. One evaluation included a formal time-motion study and noted a patient visit duration reduction of about 10 min [18]. Apparently, productiv- ity improvements were associated with less staff time socializing with colleagues [18]. Another program evalu- ation reported a 30 % reduction in missed appointments, 24 % reduction in erroneous appointments, and an overall reduction in wait times for nurse and lab technician access [21]. An extraordinarily positive program evaluation claimed a reduction of scheduling error rates from 66.5 to 2.1 % [17]. Of the retrieved observational studies, none used rigorous qualitative research methods. Although survey studies were common [17–19], few described a-priori objectives, how survey question concepts were devel- oped, how instrument validity was established, or how results were interpreted in light of an analytic frame- work. Thompson et al. Methods There were no reports of long-term sustained initiatives. Greater weight was given to findings reported in the last 5 years. The detailed key paper review did not uncover new search concepts, MeSH terms or full-text synonyms, and bibli- ography searches did not expose reports not already known from the iterative searching described above. Inquiry types (2010) conducted an observa- tional study using data gathered in ethnographic field notes, but did not report an explicit approach to data- abstraction, coding or purposeful analysis of the recorded observations [20]. Rarely were observations captured pre- Some observational reports provided detailed descrip- tions of EMR designs and pilot implementations, focusing Jawhari et al. BMC Medical Informatics and Decision Making (2016) 16:116 Page 4 of 12 Table 2 Categorization of inquiry topics Inquiry topic Citations Matters of Process 22 - Patient identification 5 - Encounter and patient management 8 - Medication management 2 - Laboratory management 2 - Document and information management 7 - Systems integration 1 - Human resource utilization 7 - Clinic efficiency 3 - Continuity of care 1 - Communications and team relations 2 - Data integrity 3 - Reporting and Analytics 3 - Auditing 1 Matters of Outcome 22 - Chronic disease guideline compliance 2 - HIV/AIDS management compliance 17 - Tuberculosis management compliance 1 - Medication reconciliation 2 - Medical errors 0 - Quality of care 1 - Maternal and child health guideline compliance 1 - Clinical decision support compliance 1 Table 2 Categorization of inquiry topics Inquiry topic Citations Matters of Process 22 - Patient identification 5 - Encounter and patient management 8 - Medication management 2 - Laboratory management 2 - Document and information management 7 - Systems integration 1 - Human resource utilization 7 - Clinic efficiency 3 - Continuity of care 1 - Communications and team relations 2 - Data integrity 3 - Reporting and Analytics 3 - Auditing 1 Matters of Outcome 22 - Chronic disease guideline compliance 2 - HIV/AIDS management compliance 17 - Tuberculosis management compliance 1 - Medication reconciliation 2 - Medical errors 0 - Quality of care 1 - Maternal and child health guideline compliance 1 - Clinical decision support compliance 1 Table 2 Categorization of inquiry topics on things like data models, software architecture and per- formance specifications [1, 15–17, 23, 24]. A common theme related to the benefits of open-source systems in resource-limited settings, presumably because lower up- front costs, with many focus on feature customization, local adaptation and hidden costs of adoption [12, 14–16]. No formal clinical trials, where an EMR-exposed group is compared to a suitable control group, were found among relevance and methods-filtered studies. However, a number of before-after time-series comparisons appeared. Inquiry types These tended to examine impacts on resources and bar- riers to sustainability, such as staffing requirements, em- ployee retention, training needs, hardware reliability and infrastructure requirements [7, 9, 10, 13, 15, 20, 25–27]. There was a tendency to report positive impacts, with unintended negative effects possibly not included in the recorded observations. Positive effects included increased access to Internet information resources [26], quicker retrieval of patient records, timely access to clinical data, more legible documentation and improved quality and safety of care [1, 6, 13, 26, 28]. - Auditing - Chronic disease guideline compliance Seventeen secondary literature reports appeared among relevance-filtered literature, commonly addressing general facilitators and impediments to EMR implementation. Reported success factors include stakeholder engage- ment in pre-implementation design, building trust among stakeholders, encouraging emergence of local leadership, nurturing embedded champions, and avoid- ing big staffing changes. Additionally, implementers are encouraged to use existing systems and software, collabor- ate with other organizations (leveraging resources), invest in backup capacity, audit user actions, provide on-site training and track usage [10, 12, 15, 18, 25]. - Maternal and child health guideline compliance - Clinical decision support compliance this reason, the retrieved literature frequently credited EMRs for introducing identity management [1, 6, 7, 11, 18], with consequent improved clinic encounter management and human resource utlization [8, 14, 19, 20, 24, 30, 31], reduced chart filing times, improved continuity of care [28, 31], reduced data integrity issues [13, 23, 32], and improved accuracy of reports [18, 20, 23]. The re- ported improvements in tracking of health exposures and outcomes, reductions in inappropriate test dupli- cation and overall improvement in care coordination [1, 6, 7, 11, 18], are all contingent on the ability to retrieve and compare multiple episodes of care for a uniquely identified patient [12]. A unique report explored the ethical ramifications of EMR implementations. The authors lamented a lack of eth- ically grounded EMR policies in developing countries and cautioned enthusiasts to heed the principle of “do no harm” when navigating change for clinics, staff and patients [29]. Inquiry topics d d Considered together, the filtered literature addressed re- curring themes about EMR design, implementation and impact. Topics covered by both primary and secondary literature were categorized into matters of health pro- cesses and health outcomes (Table 2). Effective communication is another common challenge in resource-constrained settings. Even improved legibil- ity of communications can make a difference. One study reported improved clarity of orders and lists post EMR implementation, with particular improvement in pre- scription management [14]. Others noted increased use- fulness of health data associated with EMR structured data entry [17, 33, 34]. The most commonly emphasized process improvements associated with EMR implementations relate to improved efficiency of time-consuming or error-prone tasks. The most common of these is identity management. Resource- constrained settings often have difficulty consistently identifying patients from visit to visit and from clinic to clinic, with negative impacts on continuity of care. In sub-Saharan Africa, particularly in Kenya, standardized national personal identifiers are rare [7, 8, 18]. Perhaps for Clinics operating in resource-constrained settings are often accountable to diverse government programs, donor organizations and disease-specific grant programs. Page 5 of 12 Jawhari et al. BMC Medical Informatics and Decision Making (2016) 16:116 Fig. 1 Understanding EMR implementations in limited resource settings An important reported process improvement relates to EMR report-generating capabilities which can signifi- cantly reduce the time taken to comply with agency reporting requirements [8, 9, 18, 20, 23]. Resource-constrained settings also have difficulty attract- ing, training and retaining experienced staff; process problems compounded by the need to up-skill and up- manage for transitions from paper to digital processes. The retrieved literature made frequent reference to EMR impacts on human resources. Developing EMR- permissive skills, attitudes and knowledge within a clinic setting is a commonly reported challenge. Involv- ing users early on in the process development is cited as one strategy for enhancing buy-in and increasing systems awareness [9, 20]. One study reported that user empowerment can increase self-esteem and positive views about the EMR-enabled health facility, with spin- off benefits for the community [9]. Health outcomes affected by EMR implementation can be difficult to track for slum clinics. They typically have short-term interactions with clients, little opportunity for follow-up, and outcomes that are hard to measure. Accordingly, the retrieved literature rarely discusses true EMR-associated health outcomes, and tends to emphasize surrogate outcomes like immunization and medication dispensing rates that may be associated with improved health outcomes. Inquiry topics d d However, the effects of clinical decision support [30] on surrogate outcomes, including medication tracking [13, 14], were not widely explored. Little in the retrieved literature addressed chronic disease or functional outcomes [6, 9]. Most available reports focused on HIV/AIDS and TB management, a priority of global granting agencies, with tracking of medication dispens- ing and side effect monitoring presumed to improve health outcomes. Fig. 1 Understanding EMR implementations in limited resource settings applications. Success factors are those things that au- thors emphasize as determinants of EMR impact con- sistent with the goals of EMR implementation. We suggest that there are no generic facilitators or barriers to EMR implementation applicable in all resource-constrained settings. Rather, the interplay of local systems, people, process and product consider- ations determine which success factors best predict ef- fective EMR use. This approach is consistent with what the retrieved literature reveals about the variability of facilitators and barriers to effective EMR implementa- tions in resource-constrained settings; and it may sug- gest an approach to planning future interventions. One might start with a clear statement of desired outcomes, then consider how known success factors must be adapted and prioritized to fit with the local product, process, people and systems opportunities and challenges that will shape implementation experiences (Fig. 1). Conceptual framework A conceptual framework (Fig. 1) was developed to summarize and synthesize key messages appearing in the discovered literature. This highlights four determi- nants of EMR impacts in resource-constrained settings: 1) Systems 2) People, 3) Processes, and 4) Products. Sys- tems considerations include access to a reliable power source, suitably located and protected servers and com- puters, availability of backup systems and the speed and reliability of network and Internet services. People con- siderations relate to the types of human resources avail- able, how users are trained and supported, how users interact with technology and how users are influenced by workplace attitudes and leadership. Process consider- ations include change management at the time of deployment and supports post-deployment. Product considerations relate to the electronic medical record software in play and how it inter-operates with other Processes Descriptions of process changes, intentional or uninten- tional, consequential or collateral, figure prominently in the discovered literature. A number of authors observe that EMR implementation does not, by itself, improve the efficiency or effectiveness of health care. Instead, digital systems tend to bring dysfunctional processes into focus, even aggravating bad workflows. One author suggested optimization of paper-based processes as a pre-requisite to EMR implementation [9]. Another sug- gests that development of structured paper-based data collection forms can help bridge to EMR workflows [7]. Transitional retention of some kind of paper-based workflow can reassure staff that their job will not be re- placed or drastically changed post go-live [7]. Outcomes Desired, expected or achieved outcomes from an EMR implementation vary in the discovered literature. In some resource-limited settings, implementing unique identifiers and improving patient tracking can be suf- ficient for meeting improved care coordination goals [6, 7]. Other settings seek more complex changes, in- cluding the shaping of provider decisions, making clinical decision support an important success factor [6, 30]. Some EMR implementations are credited with tracking patient outcomes, access to a shared medical rec- ord, and reduction in medical errors [1, 13]. Others are credited with improved clinic productivity [18] where bet- ter appointment management is the outcome dependent on systems, people, processes and product factors. While it is commonly assumed that EMRs should improve health care for patients and populations, some authors contend that this is more likely when research, quality improve- ment and disease surveillance are explicit goals [11–13]. Some process improvement claims are common. For example, many authors emphasize the importance of user and leadership engagement, noting how training and support can protect against negative reactions to loss of familiar workflows. Achieving meaningful user engage- ment requires investment pre and post EMR deployment. Although commonly a struggle, user engagement can be facilitated by relatively simple interventions. For example, two reports suggested that providing patients with an identification card (ID) allows them to feel involved in the EMR process, even increasing buy-in because they feel valued [8, 11], possibly by having gained visible badge of association with a prestigeous clinic [11]. Financial incen- tives can help overcome implementation hurdles for some staff [12]. Details about how the incentives might be matched to performance, and for how long, are scant. Discussion Overall, available studies of EMR implementation in resource-constrained settings appeared methodologically limited and at an early stage of development. The most relevant reports appeared within the last 5 years, there were no controlled comparison studies, and most com- munications were descriptive in nature. Hypotheses about factors affecting EMR implementations in slums can be inferred, but they have not been tested. Clear evidence-based recommendations are rare and the pre- vailing advice is often conflicting. This is understandable given wide variations in the systems, people, process and product factors at play in the settings of interest. To the extent that fundamental infrastructure (e.g., move to wireless and mobile devices), cost (e.g., available open- source EMR software), and support (e.g., emerging in- formation literate workforce) challenges are dynamic, growth in the quantity and quality of relevant literature is anticipated. People other electronic systems [7]. Health clinics in resource- constrained settings require well-designed, easy to use EMR software that can be easily customized to the needs of clinic and staff; but the published consensus is that this has yet to be realized. p Socio-technical factors–interactions between patients, providers, staff and their digital environment–are fre- quently highlighted as powerful determinants of EMR uptake and impact. Typically cited barriers include high staff turnover, absence of local technical support, and low levels of computer literacy. Organizational barriers include lack of local information system leadership or coexistence of multiple co-deployed systems without co- ordinated leadership [6, 9, 10, 25]. Improving end-user engagement might, for example, require extraordinary effort to establish rapport with clinic staff, use of multiple site visits to fully understand how workflows and operations must change, strengthen relationships with local partners, find and involve stake- holders, customize product to better fit local needs, and build reliable methods for data collection to track user behavior change [6, 9, 10, 12]. Systems Many reports highlight the importance of appropriate information systems infrastructure, such as reliable power, connectivity and networking capabilities where EMRs are deployed [7, 8, 11]. Some authors recommend specific remedies for resource-constrained settings, in- cluding installation of multiple power supplies of differ- ent types (e.g., generator, solar, battery, uninterrupted power supply) to assure continuing hardware and soft- ware function [7, 8, 11, 25]. Where mobile EMR prod- ucts link to centralized information systems, the location of telecommunications towers and service centres be- come more important considerations. Page 6 of 12 Page 6 of 12 Jawhari et al. BMC Medical Informatics and Decision Making (2016) 16:116 Products One report emphasized how limitations of currently avail- able EMR systems contribute to user resistance; especially bugs, missing features and poor performance [10]. Some commonly maligned software features are mandated by government, especially in Kenya. For example, complex security associated with sign-on processes, unrealistically complex reporting requirements, or time-consuming backup rules can be beyond the means of clinics in resource-constrained settings [7, 8]. One study suggests that challenged clinics back up data to paper rather than Page 7 of 12 Page 7 of 12 Jawhari et al. BMC Medical Informatics and Decision Making (2016) 16:116 Jawhari et al. BMC Medical Informatics and Decision Making (2016) 16:116 Since completing the literature review, two new contri- butions have appeared [35, 36]. Fritz et al. (2015) exam- ined facilitators, but not barriers, to EMR implementation in limited resource settings [35]. Organizational (e.g., hu- man resource), technical (e.g., infrastructure, Internet and power), functional (e.g., data quality and reporting) and training factors were emphasized, consistent with findings reported here. In addition, “political” and “ethical” factors were observed, which did not figure prominently in the literature considered by this review. A review by Tierney et al. (2015) referenced studies considered in our review, with similar findings [7, 11, 18]. resource-limited settings. More consistent and informative reporting about implementation studies could improve our ability to discover the most important determinants of success, and the most important harms to avoid. There is a need for rigorous qualitative research before valid quan- titative studies can be contemplated. Comparisons be- tween emerging experiential and experimental reports could be facilitated by reference to a conceptual frame- work that organizes systems, people, process and product considerations. Inclusion criteria Inclusion criteria  Include papers that focused on EMRs or EHRs  Include papers that referred to eHealth systems or health information systems (that focused on EMRs or EHRs)  Include papers that include low resource settings or limited resource settings Limiting the literature search to sub-Saharan African countries may have limited opportunities to capture pa- pers that may have discussed EMR implementations in slum areas elsewhere. Given the breadth of the initial search strategy, and the size of the initial population of studies scanned, the impression is that any missed litera- ture about EMRs in slum settings elsewhere would not be more methodologically mature or likely to yield sig- nificantly different insights.  Include papers that focused on sub-Saharan Africa, African countries  Include papers that focused on Kenya and developing countries (that focus on sub-Saharan African countries)  Include papers that focused on implementation of EMRs/EHRs or HIS systems that also referred to challenges/barriers/disadvantages and benefits/ advantages of implementation Appendix 1: Literature review properties Search checklist Given the methodological state of the available litera- ture, and the types of questions raised by that literature, it would appear that credible qualitative studies are needed. The human factors affecting EMR uptake in resource-constrained environments are complex. These need to be better characterized before good implementa- tion impact measures are designed, assessment methods are developed, evaluation frameworks validated and comparative studies become doable.  Include papers that focus on implementation of EMRs and EHRs (some bibliographic databases and countries refer to these two terms interchangeably) g y  Include papers that focus on implementation challenges/barriers/disadvantages/failures of EMRs/ EHRs/HIS  Include papers that focus on implementation benefits/advantages/successes of EMRs Limitations  Include papers that focus on implementation of EMRs in low resource settings We are aware of a number of limitations to the State-of- the-Art review reported here. The literature retrieval and iterative review process was systematic, but not validated by checks for intra and inter-rater reliability. Portuguese, French and Swahili are commonly spoken in sub-Saharan Africa, but less commonly used for health informatics communications. Nonetheless, it is possible that our English-language constraint missed potentially important articles. Although potentially important research data- bases, such as CINAHL and INEEX Explorer, were not searched, careful checks of the bibliographies of retrieved papers suggest that the English language literature re- trieval was comprehensive for the time period covered.  Include papers that focus on implementation of EMRs in slum settings  Include papers that focus on sub-Saharan Africa and Kenya Appendix 2: Search strategy Medline  Exclude papers that refer to EHRs/EMRs/HIS implemented in hospital based settings Conclusion  Include papers which document the implementation or deployment of EMRs/EHRs/HIS system where authors discuss lessons learned, risks, outcomes or recommendations Systems, people, process and product factors play an integral role in the fate of EMR implementations in sub- Saharan African countries. Increased investment and deployment is likely given growth in multi-institutional collaborations, government support and funding prior- ities. This State-of-the-Art review identifies both knowl- edges gaps and learning opportunities for EMR use in  Include papers that include both positive, and negative views/results of implementations  Include papers that discussed human resources, workflow, patient outcomes, buy-in of stakeholders, Jawhari et al. BMC Medical Informatics and Decision Making (2016) 16:116 Page 8 of 12  Exclude papers on mental health systems or mental health information/tracking systems staff input or involvement in the implementation process, information technology infrastructure, privacy, confidentiality, safety, user perceptions, user satisfaction/dissatisfaction, successes, failures, adoption, or any other factors that are included in the pre, during, and post, implementation of such systems  Exclude papers on medication management systems or medication therapy management systems py g y  Exclude paper that focus on immunization based systems  Exclude papers that focus on dental information systems or dental health systems y  Include both quantitative and qualitative studies y  Include both quantitative and qualitative studies  Include papers that refer to or focus on implementation in slum settings  Exclude papers that focus on obstetrics health information systems  Include systematic reviews or literature reviews that align with the inclusion criteria  Exclude papers that focus on occupational health information systems  Include all papers that meet inclusion criteria regardless of date  Exclude papers that focus on animal management information systems, animal health information systems and animal tracking/surveillance systems  Include all papers that meet inclusion criteria regardless of date Exclusion criteria Exclusion criteria  Exclude papers on data management systems, nutrition information systems, reporting systems, surveillance systems or emergency based data health systems that did not refer to EMRs or EHRs  Exclude papers that did not include resource- limited environments  Exclude papers that focus on EMR/EHR/HIS implementations in developed countries or countries not in sub-Saharan Africa  Exclude papers that refer to databases or systems that manage health data such as District Health Information System, National Health Information Systems, National EMR/EHR/HIS implementations Embase (1974 to 2014 December 19) Search Terms: (1974 to 2014 December 19) Search Terms: 20. Kenya.mp. [mp = title, abstract, subject headings, heading word, drug trade name, original title, device manufacturer, drug manufacturer, device trade name, keyword] 1. electronic medical record/ 2. electronic medical record*.mp. [mp = title, abstract, subject headings, heading word, drug trade name, original title, device manufacturer, drug manufacturer, device trade name, keyword] , y ] 21. 19 or 20 22. 5 and 21 23. 18 or 22 3. electronic health record*.mp. [mp = title, abstract, subject headings, heading word, drug trade name, original title, device manufacturer, drug manufacturer, device trade name, keyword] Global health (1910–2014 Week 50) Search Terms: 4. exp medical information system/ 4. exp medical information system/ 5. 1 or 2 or 3 or 4 6. low resource*.mp. [mp = title, abstract, subject headings, heading word, drug trade name, original title, device manufacturer, drug manufacturer, device trade name, keyword] 1. Medical Records Systems.mp. 1. Medical Records Systems.mp. 2. electronic medical record*.mp. [mp = abstract, title, original title, broad terms, heading words, identifiers, cabicodes] 7. resource poor.mp. [mp = title, abstract, subject headings, heading word, drug trade name, original title, device manufacturer, drug manufacturer, device trade name, keyword] 3. electronic health record*.mp. [mp = abstract, title, original title, broad terms, heading words, identifiers, cabicodes] 4. health information system*.mp. [mp = abstract, title, original title, broad terms, heading words, identifiers, cabicodes] 8. limited resources.mp. [mp = title, abstract, subject headings, heading word, drug trade name, original title, device manufacturer, drug manufacturer, device trade name, keyword] 5. 1 or 2 or 3 or 4 6. low resource*.mp. [mp = abstract, title, original title, broad terms, heading words, identifiers, cabicodes] 9. marginalized population*.mp. [mp = title, abstract, subject headings, heading word, drug trade name, original title, device manufacturer, drug manufacturer, device trade name, keyword] 7. resource poor.mp. [mp = abstract, title, original title, broad terms, heading words, identifiers, cabicodes] 8. limited resources.mp. [mp = abstract, title, original title, broad terms, heading words, identifiers, cabicodes] 10. low income.mp. [mp = title, abstract, subject headings, heading word, drug trade name, original title, device manufacturer, drug manufacturer, device trade name, keyword] d l / 9. marginalized population*.mp. [mp = abstract, title, original title, broad terms, heading words, identifiers, cabicodes] 11. exp developing country/ 10. low income.mp. [mp = abstract, title, original title, broad terms, heading words, identifiers, cabicodes] 13. Ovid MEDLINE (R) In-Process & Other Non-Indexed Citations and Ovid MEDLINE (R) 1946 to Present. Search Terms: BMC Medical Informatics and Decision Making (2016) 16:116 Page 9 of 12 Page 9 of 12 heading word, keyword heading word, protocol supplementary concept word, rare disease supplementary concept word, unique identifier] heading word, keyword heading word, protocol supplementary concept word, rare disease supplementary concept word, unique identifier] 14. exp “Africa south of the Sahara”/ 15. 6 or 7 or 8 or 9 or 10 or 11 or 12 or 13 or 14 16. (adopt* or implement* or uptake).mp. [mp = title, abstract, subject headings, heading word, drug trade name, original title, device manufacturer, drug manufacturer, device trade name, keyword] 13. (Nairobi or Kenya).mp. [mp = title, abstract, original title, name of substance word, subject heading word, keyword heading word, protocol supplementary concept word, rare disease supplementary concept word, unique identifier] 17. (challeng* or barrier* or benefit*).mp. [mp = title, abstract, subject headings, heading word, drug trade name, original title, device manufacturer, drug manufacturer, device trade name, keyword] 14. 4 and 13 18. 5 and 15 and (16 or 17) 15. 12 or 14 19. Nairobi.mp. [mp = title, abstract, subject headings, heading word, drug trade name, original title, device manufacturer, drug manufacturer, device trade name, keyword] 19. Nairobi.mp. [mp = title, abstract, subject headings, heading word, drug trade name, original title, device manufacturer, drug manufacturer, device trade name, keyword] Ovid MEDLINE (R) In-Process & Other Non-Indexed Citations and Ovid MEDLINE (R) 1946 to Present. Search Terms: Ovid MEDLINE (R) In-Process & Other Non-Indexed Citations and Ovid MEDLINE (R) 1946 to Present. Search Terms:  Exclude papers that refer to hospital information systems, hospital management information systems, health management information systems, or health information systems implemented in a hospital setting 1. computerized medical record system.mp. or exp Medical Records Systems, Computerized/ y p p g  Exclude papers that included or solely focused on financial analysis, cost, return on investment of EMRs 2. (electronic medical record* or electronic health record* or emr or ehr).mp. [mp = title, abstract, original title, name of substance word, subject heading word, keyword heading word, protocol supplementary concept word, rare disease supplementary concept word, unique identifier]  Exclude papers that just focused on computerized physician order entry (CPOE) systems  Exclude papers that focused on clinical decision support systems or clinical summaries systems  Exclude papers that exclusively focused on electronic personal health records, electronic patient medical records, electronic patient registries, or patient centered health records 3. exp Health Information Systems/ 4. 1 or 2 or 3 5. Developing Countries/  Exclude papers that focused solely on personal digital assistant (PDA) 6. exp Poverty Areas/ or exp Poverty/ 7. exp “Africa South of the Sahara”/ 8. (low resource* or limited resource* or low income or resource poor or poverty or developing countr* or developing world).mp. [mp = title, abstract, original title, name of substance word, subject heading word, keyword heading word, protocol supplementary concept word, rare disease supplementary concept word, unique identifier]  Exclude papers that focused on mobile health technologies/systems, handheld technologies/systems/ computers and/or mhealth strategies/policies  Exclude papers that only focused on pharmacy stock systems or pharmacy medical systems  Exclude papers on ambulance systems or ambulatory care systems q 9. 5 or 6 or 7 or 8 10. 4 and 9 9. 5 or 6 or 7 or 8 10. 4 and 9 9. 5 or 6 or 7 or 8  Exclude papers on diabetes management systems or chronic disease management systems 11. (adopt* or implement* or uptake or challeng* or benefit* or barrier*).mp. [mp = title, abstract, original title, name of substance word, subject  Exclude paper on laboratory information systems or laboratory management information systems Jawhari et al. Embase (developing countr* or developing world).mp. [mp = title, abstract, subject headings, heading word, drug trade name, original title, device manufacturer, drug manufacturer, device trade name, keyword] 11. Developing Countries/ 12. exp Poverty/ 13. exp “Africa South of Sahara”/ Page 10 of 12 Page 10 of 12 Page 10 of 12 Jawhari et al. BMC Medical Informatics and Decision Making (2016) 16:116 14. (developing countr* or developing world).mp. [mp = abstract, title, original title, broad terms, heading words, identifiers, cabicodes] 15. 6 or 7 or 8 or 9 or 10 or 11 or 12 or 13 or 14 16. (adopt* or implement* or uptake).mp. [mp = abstract, title, original title, broad terms, heading words, identifiers, cabicodes] 17. (challeng* or barrier* or benefit*).mp. [mp = abstract, title, original title, broad terms, heading words, identifiers, cabicodes] 18. 16 or 17 19. nairobi.mp. [mp = abstract, title, original title, broad terms, heading words, identifiers, cabicodes] 20. kenya.mp. [mp = abstract, title, original title, broad terms, heading words, identifiers, cabicodes] 21. 5 and 15 and 18 22. 19 or 20 23. 5 and 22 24. 21 or 23 14. (developing countr* or developing world).mp. [mp = abstract, title, original title, broad terms, heading words, identifiers, cabicodes] 10. 4 and 9 11. (adopt* or implement* or uptake or challeng* or benefit* or barrier*).mp. [mp = title, abstract, original title, name of substance word, subject heading word, keyword heading word, protocol supplementary concept word, rare disease supplementary concept word, unique identifier] 15. 6 or 7 or 8 or 9 or 10 or 11 or 12 or 13 or 14 16. (adopt* or implement* or uptake).mp. [mp = abstract, title, original title, broad terms, heading words, identifiers, cabicodes] 16. (adopt* or implement* or uptake).mp. [mp = abstract, title, original title, broad terms, heading words, identifiers, cabicodes] 17. (challeng* or barrier* or benefit*).mp. [mp = abstract, title, original title, broad terms, heading words, identifiers, cabicodes] 18 16 17 12. 10 and 11 (total papers 206) 13. (Nairobi or Kenya).mp. [mp = title, abstract, original title, name of substance word, subject heading word, keyword heading word, protocol supplementary concept word, rare disease supplementary concept word, unique identifier] 19. nairobi.mp. [mp = abstract, title, original title, broad terms, heading words, identifiers, cabicodes] pp y p q 14. 4 and 13 15. 12 or 14 14. 4 and 13 14. 4 and 13 15. 12 or 14 15. 12 or 14 (All EMB Reviews) EBM Reviews - Cochrane Database of Systematic Re- views 2005 to November 2014, EBM Reviews-ACP Journal Club 1991 to December 2014, EBM Reviews-Database of Abstracts of Reviews of Effects 4th Quarter 2014, EBM Reviews-Cochrane Central Register of Controlled Trials November 2014, EBM Reviews-Cochrane Methodology Register 3rd Quarter 2012, EBM Reviews-Health Technol- ogy Assessment 4th Quarter 2014, EBM Reviews-NHS Economic Evaluation Database 4th Quarter 2014 Search Terms 3. (“electronic medical record system”) + (“challenge” or “benefit” or “advantages” or “disadvantages” or “implement” or “deploy” or “adopt”) + (“Nairobi” or “Kenya”) 4. (“electronic medical record system” or “electronic health record system” or “health information system”) + (“challenges” or “benefits” or “advantages” or “disadvantages” or “implement” or “deploy” or “adopt”) + (“limited resource settings” or “limited settings” or “slums” or “poverty areas”) 1. computerized medical record system.mp. or exp Medical Records Systems, Computerized/ 5. (“electronic medical record system” or “electronic health record system” or “health information system”) + (“challenges” or “benefits” or “advantages” or “disadvantages” or “implement” or “deploy” or “adopt”) + (“Kenya” or “Nairobi” or “Africa South”) + (“limited resource settings” or “limited settings” or “slums” or “poverty areas”) 5. (“electronic medical record system” or “electronic health record system” or “health information system”) + (“challenges” or “benefits” or “advantages” or “disadvantages” or “implement” or “deploy” or “adopt”) + (“Kenya” or “Nairobi” or “Africa South”) + (“limited resource settings” or “limited settings” or “slums” or “poverty areas”) 2. (electronic medical record* or electronic health record* or emr or ehr).mp. [mp = title, abstract, original title, name of substance word, subject heading word, keyword heading word, protocol supplementary concept word, rare disease supplementary concept word, unique identifier] 3. exp Health Information Systems/ 3. exp Health Information Systems/ Google Search Search Strings 1. “electronic medical record system” Kenya 9. 5 or 6 or 7 or 8 Cochrane 2. (“electronic medical record system” or “electronic health record system” or “health information system”) + (“Kenya” or “Nairobi” or “Africa South”) (All EMB Reviews) Funding g This work was supported by Innovative Canadians for Change and the Mitacs-Accelerate Program (www.mitacs.ca) studentship grant. This work was supported by Innovative Canadians for Change and the Mitacs-Accelerate Program (www.mitacs.ca) studentship grant. 11. Tierney WM, Rotich JK, Smith FE, Bii J, Einterz RM, Hannan TJ. Crossing the “digital divide:” implementing an electronic medical record system in a rural Kenyan health center to support clinical care and research. AMIA Annual Symposium Proceedings. 2002:792–5. http://www.ncbi.nlm.nih.gov/pmc/ articles/PMC2244335/. Accessed 6 Jan 2015. Consent for publication Not applicable. 15. Mamlin BW, Biondich PG, Wolfe BA, et al. Cooking up an open source EMR for developing countries: OpenMRS-a Recipe for Successful Collaboration. AMIA Annual Symposium Proceedings. 2006:529–33. http://www.ncbi.nlm.nih.gov/ pmc/articles/PMC1839638/pdf/AMIA2006_0529.pdf. Accessed 12 June 2014. Google scholar Search Search Strings: “Talkin’ about a revolution”: How electronic health records can facilitate the scale-up of HIV care and treatment and catalyze primary care in resource-constrained settings. J Acquir Immune Defic Syndr. 2009;52:S54–7. doi:10.1097/QAI.0b013e3181bbcb67. 7. (“electronic medical record system”) + (“developing countries”) + (“challenges” or “benefits” or “implement” or “deploy” or “adopt”) or y 7. Hannan TJ, Rotich JK, Odero WW, et al. The Mosoriot medical record system: design and initial implementation of an outpatient electronic record system in rural Kenya. Int J Med Inform. 2000;60(1):21–8. doi:10.1016/S1386-5056(00)00068-X. 8. (“electronic medical record system”) + (“developing countries”) + (“World Health Organization”) 8. Hannan TJ, Tierney WM, Rotich JK, et al. The MOSORIOT medical record system (MMRS) phase I to phase II implementation: an outpatient computer-based medical record system in rural Kenya. MEDINFO 2001. Stud Health Technol Inform. 2001;84(1):619–22. doi:10.3233/978-1-60750-928-8-619. 9. (“electronic medical record system”) + (“developing countries”) + (“United Nations”) countries”) + (“United Nations”) 9. Kamadjeu RM, Tapang EM, Moluh RN. Designing and implementing an electronic health record system in primary care practice in sub-Saharan Africa: a case study from Cameroon. Inform Prim Care. 2005;13(3):179–86. doi: http://dx.doi.org/10.14236/jhi.v13i3.595. 9. Kamadjeu RM, Tapang EM, Moluh RN. Designing and implementing an electronic health record system in primary care practice in sub-Saharan Africa: a case study from Cameroon. Inform Prim Care. 2005;13(3):179–86. doi: http://dx.doi.org/10.14236/jhi.v13i3.595. Ethics approval and consent to participate 16. Millard PS, Bru J, Berger CA. Open-source point-of-care electronic medical records for use in resource-limited settings: systematic review and questionnaire surveys. BMJ Open. 2012;2, e000690. doi:10.1136/bmjopen-2011-000690. Author details 1 1Department of Medicine, Faculty of Medicine & Dentistry, University of Alberta, Clinical Sciences Building, 8440-112 St NW 5th floor, 5-112E, T6G 2B7 Edmonton, AB, Canada. 2Innovative Canadians for Change, Edmonton, AB, Canada. 3Sherwood Park Primary Care Network, Sherwood Park, AB, Canada. 4Faculty of Community Services, School of Occupational and Public Health, Ryerson University, Toronto, ON, Canada. 17. Castelnuovo B, Kiragga A, Afayo V, et al. Implementation of provider-based electronic medical records and improvement of the quality of data in a large HIV program in sub-Saharan Africa. Plos ONE. 2012;7(12), e51631. doi:10.1371/journal.pone.0051631. 18. Rotich JK, Hannan TJ, Smith FE, et al. Installing and implementing a computer-based patient record system in sub-Saharan Africa: The mosoriot medical record system. J Am Med Inform Assoc. 2003;10(4):295–303. http://dx.doi.org/10.1197/jamia.M1301. 18. Rotich JK, Hannan TJ, Smith FE, et al. Installing and implementing a computer-based patient record system in sub-Saharan Africa: The mosoriot medical record system. J Am Med Inform Assoc. 2003;10(4):295–303. http://dx.doi.org/10.1197/jamia.M1301. Received: 4 May 2016 Accepted: 19 August 2016 Received: 4 May 2016 Accepted: 19 August 2016 19. Were MC, Emenyonu N, Achieng M, et al. Evaluating a scalable model for implementing electronic health records in resource-limited settings. J Am Med Inform Assoc. 2010;17(3):237–44. doi:10.1136/jamia.2009.002303. 19. Were MC, Emenyonu N, Achieng M, et al. Evaluating a scalable model for implementing electronic health records in resource-limited settings. J Am Med Inform Assoc. 2010;17(3):237–44. doi:10.1136/jamia.2009.002303. Availability of data and materials The datasets supporting the conclusions of this article are included within the article and its additional files, Appendix 1 and Appendix 2. Further information are also available at the University of Alberta repository, http://hdl.handle.net/10402/era.42770. 12. Tierney WM, Rotich JK, Hannan TJ, et al. The AMPATH Medical Record System: creating, implementing, and sustaining an electronic medical record system to support HIV/AIDS care in Western Kenya. MEDINFO 2007: Proceedings of the 12th World Congress on Health (Medical) Informatics; Studies in Health Technology and Informatics. 2007;129(Pt 1):372–6. Accessed 6 Jan 2015. Acknowledgements Th h ld l k The authors would like to thank the University of Alberta Faculty of Medicine & Dentistry Department of Medicine for access to facilities, computer equipment and software. 10. Mohammed-Rajput NA, Smith DC, Mamlin B, Biondich P, Doebbeling BN, OpenMRS Collaborative Investigators. OpenMRS, A global medical records system collaborative: factors influencing successful implementation. AMIA Annual Symposium Proceedings 2011. 2011:960–68. http://www.ncbi.nlm.nih.gov/pmc/ articles/PMC3243141/pdf/0960_amia_2011_proc.pdf. Accessed 6 Jan 2015. 10. Mohammed-Rajput NA, Smith DC, Mamlin B, Biondich P, Doebbeling BN, OpenMRS Collaborative Investigators. OpenMRS, A global medical records system collaborative: factors influencing successful implementation. AMIA Annual Symposium Proceedings 2011. 2011:960–68. http://www.ncbi.nlm.nih.gov/pmc/ articles/PMC3243141/pdf/0960_amia_2011_proc.pdf. Accessed 6 Jan 2015. Authors’ contributions ll h b d All authors contributed to the paper. BJ and RH conceived, designed and conducted the study. DL, LK, DZ reviewed the findings, edited the paper and provided general support. All authors approved the final draft of the manuscript. 13. Williams F, Boren SA. The role of the electronic medical record (EMR) in care delivery development in developing counties: a systematic review. Inform Prim Care. 2008;16(2):139–45. doi:http://dx.doi.org/10.14236/jhi.v16i2.685. 13. Williams F, Boren SA. The role of the electronic medical record (EMR) in care delivery development in developing counties: a systematic review. Inform Prim Care. 2008;16(2):139–45. doi:http://dx.doi.org/10.14236/jhi.v16i2.685. Google scholar Search Search Strings: Google scholar Search Search Strings: 4. 1 or 2 or 3 4. 1 or 2 or 3 5. Developing Countries/ 6. exp Poverty Areas/ or exp Poverty/ 5. Developing Countries/ 6. exp Poverty Areas/ or exp Poverty/ 5. Developing Countries/ 5. Developing Countries/ A / 6. exp Poverty Areas/ or exp Poverty/ 1. (“electronic medical record system” or “electronic health record system” or “health information system”) + (“Kenya” or “Africa South”) 7. exp “Africa South of the Sahara”/ 8. (low resource* or limited resource* or low income or resource poor or poverty or developing countr* or developing world).mp. [mp = title, abstract, original title, name of substance word, subject heading word, keyword heading word, protocol supplementary concept word, rare disease supplementary concept word, unique identifier] 2. (“electronic medical record system” or “electronic health record system” or “health information system”) + (“Kenya”) 3. (“electronic medical record system” or “electronic health record system” or “health information system”) + (“developing countries”) y ) ( p g ) Page 11 of 12 Jawhari et al. BMC Medical Informatics and Decision Making (2016) 16:116 Page 11 of 12 Page 11 of 12 4. (“electronic medical record system” or “electronic health record system” or “health information system”) + (“developing countries”) + (“challenges” or “benefits” or “advantages” or “disadvantages” or “implement” or “deploy” or “adopt”) of tuberculosis epidemiology. Med Inform Decis Mak. 2012;12(125):1–10. doi:10.1186/1472-6947-12-125. of tuberculosis epidemiology. Med Inform Decis Mak. 2012;12(125):1–10. doi:10.1186/1472-6947-12-125. 3. Ekouevi DK, Karcher S, Coffie PA. Strengthening health systems through HIV monitoring and evaluation in sub-Saharan Africa. Curr Opin HIV and Aids J. 2011;6(4):245–50. doi:10.1097/COH.0b013e3283479316. 4. Grant MJ, Booth A. A typology of reviews: an analysis of 14 review types and associated methodologies. Health Inf Libr J. 2009;26(2):91–108. doi:10.1111/j.1471-1842.2009.00848.x. 5. (“electronic medical record system” or “electronic health record system” or “health information technology”) + (“developing countries”) 5. Azubuike MC, Ehiri JE. Health information systems in developing countries: benefits, problems, and prospects. J R Soc Promot Health. 1999;119(3):180–4. doi:10.1177/146642409911900309. 6. (“electronic medical record system” or “health information technology”) + (“developing countries”) 6. Braitstein P, Robert M, Einterz JES, Kimaiyo S, Tierney W. “Talkin’ about a revolution”: How electronic health records can facilitate the scale-up of HIV care and treatment and catalyze primary care in resource-constrained settings. J Acquir Immune Defic Syndr. 2009;52:S54–7. doi:10.1097/QAI.0b013e3181bbcb67. 6. Braitstein P, Robert M, Einterz JES, Kimaiyo S, Tierney W. Competing interests Competing interests The authors declare that they have no competing interests. 14. O’Mahony D. Implementing an electronic medical record system in a rural general practice. South Africa Family Practice. 2009;51(4):346–7. doi:10.1080/20786204.2009.10873878. 14. O’Mahony D. Implementing an electronic medical record system in a rural general practice. South Africa Family Practice. 2009;51(4):346–7. doi:10.1080/20786204.2009.10873878. References 1. Fraser HS, Biondich P, Moodley D, Choi S, Mamlin BW, Szolovits P. Implementing electronic medical record systems in developing counties. Inform Prim Care. 2005;13(2):83-95. doi:http://dx.doi.org/10.14236/jhi.v13i2.585. 20. Thompson A, Castle E, Lubeck P, Makarfi PS. Experience implementing OpenMRS to support maternal and reproductive health in Northern Nigeria [abstract]. MEDINFO 2010. Stud Health Technol Inform. 2010;160(1):332–6. doi:10.3233/978-1-60750-588-4-332. 20. Thompson A, Castle E, Lubeck P, Makarfi PS. Experience implementing OpenMRS to support maternal and reproductive health in Northern Nigeria [abstract]. MEDINFO 2010. Stud Health Technol Inform. 2010;160(1):332–6. doi:10.3233/978-1-60750-588-4-332. 2. Fraser HS, Thomas D, Tomaylla J, et al. Adaptation of a web-based, open source electronic medical record system platform to support a large study 2. Fraser HS, Thomas D, Tomaylla J, et al. Adaptation of a web-based, open so rce electronic medical record s stem platform to s pport a large st d Page 12 of 12 Jawhari et al. BMC Medical Informatics and Decision Making (2016) 16:116 Jawhari et al. BMC Medical Informatics and Decision Making (2016) 16:116 21. Alamo ST, Wagner GJ, Sunday P, et al. Electronic medical records and same day patient tracing improves clinic efficiency and adherence to appointments in a community based HIV/AIDS care program, in Uganda. AIDS Behav. 2012;16(2):368–74. doi:10.1007/s10461-011-9996-9. 22. Talisuna S. Electronic medical records and same-day patient tracing improves clinic efficiency and adherence to appointments in a community- based HIV/AIDS care program in Uganda [abstract]. 7th International Conference on HIV Treatment and Prevention Adherence, 2012. Accessed 7 Jan 2015. 23. Allen C, Jazayeri D, Miranda J, et al. Experience in implementing the OpenMRS medical record system to support HIV treatment in Rwanda. MEDINFO 2007. Stud Health Technol Inform. 2007;129(1):382–6. http://www. ncbi.nlm.nih.gov/pubmed/17911744. Accessed 14 Jan 2015. 24. Nucita A, Bernava GM, Bartolo M, et al. A global approach to the management of EMR (electronic medical records) of patients with HIV/AIDS in sub-Saharan Africa: the experience of DREAM software. BMC Med Inform Decis Mak. 2009;9(42):1–13. doi:10.1186/1472-6947-9-42. 25. Fraser HS, Blaya J. Implementing medical information systems in developing countries, what works and what doesn’t. American Medical Informatics Association-Symposium Proceedings. 2010:232–36. http://www.ncbi.nlm.nih. gov/pmc/articles/PMC3041413/pdf/amia-2010_sympproc_0232.pdf. Accessed 29 Mar 2014. 26. Akanbi MO, Ocheke AN, Agaba PA, et al. Use of electronic health Records in sub-Saharan Africa: progress and challenges. J Med Trop. 2012;14(1):1–6. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4167769/pdf/nihms380682.pdf. Accessed 6 Jan 2015. 27. Sheikh M. Digital Health information system in Africa’s resource poor countries: current challenges and opportunities. J Health Inform Dev Ctries. 2014;8(1):78–87. http://www.jhidc.org/index.php/jhidc/article/view/118/162. References Accessed 6 Jan 2015. 28. Moster-Phipps N, Pottas D, Korpela M. Improving continuity of care through the use of electronic records: a South African perspective. South African Family Practice. 2012;54(4):326–31. doi:10.1080/20786204.2012.10874244. 29. Were MC, Meslin EM. Ethics of implementing electronic health records in developing countries: points to consider. AMIA Annual Symposium Proceedings, 2011. 2011. http://www.ncbi.nlm.nih.gov/pmc/articles/ PMC3243215/pdf/1499_amia_2011_proc.pdf. Accessed 6 Jan 2015. 30. Amoroso CL, Akimana B, Wise B, Fraser HS. Using electronic medical records for HIV care in rural Rwanda. MEDINFO 2010. Stud Health Technol Inform. 2010;160(1):337–41. doi:10.3233/978-1-60750-588-4-337. 31. Moster-Phipps N, Pottas D, Korpela M. A Socio-technical approach to continuity of care and electronic records in the South African context. MEDINFO 2010. Proceedings of the 13th World Congress on Medical Informatics, 2010. 2010;160(1):406–10. doi:10.3233/978-1-60750-588-4-406. 32. Manders EJ, José E, Solis M, Burlison J, Nhampossa JL, Moon T. Implementing OpenMRS for patient monitoring in an HIV/AIDS care and treatment program in rural Mozambique. MEDINFO 2010. Proceedings of the 13th World Congress on Medical Informatics, Studies in Health Technology and Informatics. 2010;160(1):411–5. doi:10.3233/978-1-60750-588-4-411. 33. Blaya JA, Fraser HSF, Holt B. E-Health technologies show promise in developing countries. Health Aff. 2010;29(2):244–51. doi:10.1377/hlthaff.2009.0894. 34. Kalogriopoulos NA, Baran J, Nimunkar AJ, Webster JG. Electronic medical record systems for developing countries: review. 31st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBS). 2009:1730–3. doi:10.1109/IEMBS.2009.5333561. 35. Fritz F, Tilahun B, Dugas M. Success criteria for electronic medical record implementations in low-resource settings: a systematic review. J Am Med Inform Assoc. 2015;22(2):479–88. 35. Fritz F, Tilahun B, Dugas M. Success criteria for electronic medical record implementations in low-resource settings: a systematic review. J Am Med Inform Assoc. 2015;22(2):479–88. Submit your next manuscript to BioMed Central and we will help you at every step: 33. Blaya JA, Fraser HSF, Holt B. E-Health technologies show promise in developing countries. Health Aff. 2010;29(2):244–51. doi:10.1377/hlthaff.2009.0894. Submit your next manuscript to BioMed Central and we will help you at every step: Submit your next manuscript to BioMed Central and we will help you at every step: 36. Tierney WM, Sidle JE, Diero LO, et al. Assessing the impact of a primary care electronic medical record system in three kenyan rural health centers. Journal American Medical Informatics Association. 2015:1–18. doi:10.1093/jamia/ocv074. 36. Tierney WM, Sidle JE, Diero LO, et al. Assessing the impact of a primary care electronic medical record system in three kenyan rural health centers. Journal American Medical Informatics Association. 2015:1–18. doi:10.1093/jamia/ocv074. • We accept pre-submission inquiries • Our selector tool helps you to find the most relevant journal • We provide round the clock customer support • Convenient online submission • Thorough peer review • Inclusion in PubMed and all major indexing services • Maximum visibility for your research Submit your manuscript at www.biomedcentral.com/submit and we will help you at every step:
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Psychosis risk research versus daily prognosis uncertainties: A qualitative study of French youth psychiatrists’ attitudes toward predictive practices
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Psychosis risk research versus daily prognosis uncertainties: A qualitative study of French youth psychiatrists’ attitudes toward predictive practices L il B it M i R M B F li d Ni l H k Leila Benoit, Marie Rose Moro, Bruno Falissard, Nicolas Henckes To cite this version: Leila Benoit, Marie Rose Moro, Bruno Falissard, Nicolas Henckes. Psychosis risk research versus daily prognosis uncertainties: A qualitative study of French youth psychiatrists’ attitudes toward predictive practices. PLoS ONE, 2017, 12 (7), pp.e0179849. ￿10.1371/journal.pone.0179849￿. ￿hal-03480076￿ Editor: Therese van Amelsvoort, Maastricht University, NETHERLANDS Editor: Therese van Amelsvoort, Maastricht University, NETHERLANDS Received: January 12, 2017 Accepted: June 5, 2017 Published: July 19, 2017 Copyright: © 2017 Benoit et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Editor: Therese van Amelsvoort, Maastricht University, NETHERLANDS University, NETHERLANDS Received: January 12, 2017 Accepted: June 5, 2017 Published: July 19, 2017 Received: January 12, 2017 Accepted: June 5, 2017 Published: July 19, 2017 Method Copyright: © 2017 Benoit et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The Grounded Theory is an agreed-upon qualitative method in social science field that links subjective experiences (individual narratives) to social processes (professional norms and mental health policies). 12 French youth psychiatrists were interviewed about psychosis early management and their daily prognosis practices with teenagers. Data Availability Statement: The study’s full- length interviews cannot be made publicly available due to the sensitive content and identifying information contained in them. However, relevant excerpts of these interviews can be made available to interested researchers upon request to the corresponding author at laelia@benoit.nom.fr. Data requests cannot be directed to a committee because sociological studies’ registrations were not required in France when this study has been designed. Additionally, a Supporting Information file with relevant excerpts is included with the Psychosis risk research versus daily prognosis uncertainties: A qualitative study of French youth psychiatrists’ attitudes toward predictive practices Laelia Benoit1,2*, Marie Rose Moro1,2☯, Bruno Falissard2☯, Nicolas Henckes3 Laelia Benoit1,2*, Marie Rose Moro1,2☯, Bruno Falissard2☯, Nicolas Henckes3 1 Department of Psychiatry at Cochin hospital, Paris, France, 2 CESP, INSERM U1018, Universite´ Paris- Saclay, Univ. Paris-Sud, UVSQ, Univ. Paris-Descartes, Paris, France, 3 CERMES3, CNRS, Villejuif, France Laelia Benoit1,2*, Marie Rose Moro1,2☯, Bruno Falissard2☯, Nicolas Henckes3 1 Department of Psychiatry at Cochin hospital, Paris, France, 2 CESP, INSERM U1018, Universite´ Paris- Saclay, Univ. Paris-Sud, UVSQ, Univ. Paris-Descartes, Paris, France, 3 CERMES3, CNRS, Villejuif, France 1 Department of Psychiatry at Cochin hospital, Paris, France, 2 CESP, INSERM U1018, Universite´ Paris- Saclay, Univ. Paris-Sud, UVSQ, Univ. Paris-Descartes, Paris, France, 3 CERMES3, CNRS, Villejuif, France a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 ☯These authors contributed equally to this work. * laelia@benoit.nom.fr ☯These authors contributed equally to this work. * laelia@benoit.nom.fr HAL Id: hal-03480076 https://cnrs.hal.science/hal-03480076v1 Submitted on 19 Jan 2022 L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. RESEARCH ARTICLE Background Citation: Benoit L, Moro MR, Falissard B, Henckes N (2017) Psychosis risk research versus daily prognosis uncertainties: A qualitative study of French youth psychiatrists’ attitudes toward predictive practices. PLoS ONE 12(7): e0179849. https://doi.org/10.1371/journal.pone.0179849 Over the last twenty years, predicting psychosis has become a priority of both research and policies. Those approaches include the use of the At Risk Mental State category (ARMS) and of standardized predictive tools. In comparison to most developed countries, early inter- ventions programs are only little developed in France. However, cases of young patients presenting unclear symptoms that might be a beginning psychosis or might as well reflect some adolescent unease are commonplace in psychiatry. Yet little is known about the rou- tine practices of youth psychiatrists regarding psychosis risk management. Do they antici- pate mental disorders? Abstract OPEN ACCESS Citation: Benoit L, Moro MR, Falissard B, Henckes N (2017) Psychosis risk research versus daily prognosis uncertainties: A qualitative study of French youth psychiatrists’ attitudes toward predictive practices. PLoS ONE 12(7): e0179849. https://doi.org/10.1371/journal.pone.0179849 Introduction Over the last twenty years the rise of Early Intervention in Psychiatry has stimulated the crea- tion of centers specialized in the assessment and treatment of patients at an early stage or even at risk of psychosis [1–3]. Yet in many countries these centers are not accessible to all patients, who, as a consequence, are seen by psychiatrists who do not propose a standardized assess- ment of the risk condition. Even when a specialized consultation is accessible, a psychiatrist might have to decide whether the unclear symptoms presented by his patient might be the early signs of a psychosis or not in order to refer him for assessment. Little is known, however, regarding the attitudes of psychiatrists towards these situations. Competing interests: The authors have declared that no competing interests exist. This study was conducted in France where centers of expertise in early interventions are not fully developed. If there has been an interest from the media and the higher health admin- istration in early intervention strategies [4–6], today only a few centers offer assessment and care for prodromal patients, most of them in the Paris region [7]. On another hand youth psy- chiatry is well developed thanks to the existence of an array of specialized facilities, including university consultations centers, adolescent health centers combining different specialized consultations—such as psychiatry, general medicine gynecology, dermatology -, as well as psy- chiatric consultations in many community mental health centers and private consultation. France has among the highest number of practicing psychiatrists and a strong influence of psy- choanalysis. Universal coverage of health costs creates a system accessible to young people. In order to grasp the present implementation of early interventions, a local assessment of daily practices appears particularly relevant. According to Christakis’ seminal work on prognosis in medicine, two different concepts of “prognosis” can be distinguished [8]. On the one hand “prognosis” refers to the theoretical course of a given disorder, as it is described for instance in handbooks. In that sense, even if there is scientific evidence that its course is more favourable than traditionally thought [9–12], schizophrenia remains usually conceived as a chronic disease in the public opinion; while depression, for instance, should not last longer than a few months. A second meaning of prog- nosis refers to the practice of envisioning the future course of a disorder in a given patient. Conclusion article. The transcript excerpts contained within the Supporting Information file do not contain information that may identify study participants. Anticipating a psychosis onset remains a highly uncertain task for psychiatrists. In France, psychiatrists’ inconspicuous risk management might be supported by the universal costs coverage that is not conditional on a diagnosis disclosure. Funding: This work is part of a project that explores the development of institutions promoting predictive psychiatry addressed for a young public in France, Germany, and Switzerland. It received funding from Paris City, through the project "Psychosis risk and misfortune anticipation in contemporary psychiatry, a sociological approach” and from the national research funding (A.N.R.) “PSYFRING on psychiatry fringes, an after war history and sociology of early psychosis in France and Germany”. Psychosis risk research versus daily prognosis uncertainties Results If all participants were aware of early intervention programs, most of them did not make use of standardized scales. Psychiatrists’ reluctance toward a psychosis risk standardized assessment was shaped by three difficulties: first the gap between theoretical knowledge and practice; second their impossibility to make reliable prognoses; and third, the many uncertainties surrounding medical judgment, adolescence and the nature of psychosis. Nev- ertheless, they provided their young patients with multiple months follow up without disclos- ing any risk category. 1 / 16 PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 Methods Participants were contacted via an email sent to the team mailing list of 4 public psychiatry departments of the Paris Region and of 2 community mental health centers. The same email was sent to two private practice contact-list to patients in the public services and the mailing list of a professional society (French Society of Child and Adolescent Psychiatry, SFPEADA). The email was titled “Anticipating young patients’ future: is prognosis part of your practice?” and proposed a one hour long interview on questions of prognosis. No retribution was offered. Twelve youth psychiatrists (6 women, 6 men) aged from 28 to 70, and working in a variety of settings agreed to participate. In order to ensure confidentiality, numbers were used in this article to refer to participants, Table 1. The interviews took place at their office and were semi- structured, using a schedule comprising a series of themes to be addressed during the session. The schedule was developed after a review of the relevant psychiatric and sociological litera- ture. The questions were meant to focus on the problem of psychosis risk and open a free dia- logue about its daily management: when you see a teenager presenting unclear symptoms that may be early signs of psychosis, do you feel able to predict psychotic transition? If not, do you however expect some difficulties? What appears a priority for his future? Do you make use of prevalence statistics or specific tools to assess psychosis risk? Do you refer your patients to expert centers? The interviews were recorded, fully transcribed and analyzed using the Grounded Theory (GT) methodology [13]. Inspired by ethnographical studies then theorized by Glaser and Strauss [14], GT is an agreed-upon standard for social sciences research since the 1960’s [15]. The Grounded Theory links social structures with processes occurring at an individual level by focusing on themes that represent underlying phenomena, interactions and their consequences [13]. As in other inductive methods, it is not necessary to define an exact number of respondents before the research begins. The data are coded in order to generate cat- egories which are then validated through constant comparisons as new interviews are done [16]. Thus data analysis, further sampling and theoretical development are simultaneously developed until saturation is reached allowing to build a new theory about the subject of research [14]. Results As part of our sociological perspective, this results section reflects the opinions of the inter- viewees—not the authors’ ones. For instance, we asked questions related to psychosis, but par- ticipants answered focusing on schizophrenia. Later on, the discussion section will analyze these views in the light of both medical sociology and the field of ARMS research. Introduction In this meaning prognosis might be broken down into three components: • the first is foreseeing, that is envisioning the future of this particular patient; • the second component consists of anticipating, that is acting on the basis of this prevision in order to prevent or manage an event that has to come; • the last component of prognosis is communicating to the patient this prevision, in other words “predicting”. In this second meaning, prognosis is a major dimension of medical practice, and yet it remains understudied. In a sociological perspective, this interdisciplinary study does not aim at providing a review of scientific evidence of early intervention efficiency. We evaluated a sample of French adolescent psychiatrists’ contemporary views regarding early intervention. PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 2 / 16 Psychosis risk research versus daily prognosis uncertainties We focused on their daily practice of prognosis: To what extent do they think that psychosis may be anticipated? How do they themselves make anticipations about the future of their patients? Methods To ensure reliability, the analysis is repeated by more than one researcher, a pro- cess which is called triangulation [17]. In this study, two researchers (LB and NH) indepen- dently coded and analyzed all data [18], and their findings were discussed during meetings of our research team (LB, NH, MRM, BF). The gap between research and practice If all participants were aware of early intervention programs, most of them did not make use of predictive scales such as the CAARMS or the SIPS [19], nor did they refer their patients to early management centers. Actually, it would not make sense for all practitioners to use them, as these scales require extensive training. While ARMS assessment instruments do not predict psychosis in an individual, our participants think that they have the ambition to do so, and 3 / 16 PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 4 / 16 Psychosis risk research versus daily prognosis uncertainties « I know the center of expertise. But I prefer to handle things myself a while, even with the first months fuzziness, than to expose the patient and his family to a check-list concluding “you are psychotic”. Well, even colleagues working in those centers say that one should be careful, that there is no 100% guarantee. » (psychiatrist number 5—see Table 1) Only one psychiatrist used the Comprehensive Assessment of At Risk Mental States (CAARMS) among various diagnostic instruments in her daily work. Nevertheless, she stressed that assessment results did not bring her any certitude about the problems a young patient experienced. “I followed this patient for 4 years, until his late teens. In the end, I am still not sure about his diagnosis. Parents reclaim standardized assessments. So we assess, we check things up, we give a sort of diagnostic listing! [laugh] But I am still not sure. Well, anyway, we evaluated.» “I followed this patient for 4 years, until his late teens. In the end, I am still not sure about his diagnosis. Parents reclaim standardized assessments. So we assess, we check things up, we give a sort of diagnostic listing! [laugh] But I am still not sure. Well, anyway, we evaluated.» (7) 2. Statistics do not help to predict psychosis. Even psychiatrists involved in outcome studies acknowledged a difficulty to match both statistical data and clinical sense. « For this girl, I would say that it will turn into a bipolar disorder. But we conducted a follow up study among 80 teens diagnosed with a bipolar disorder type I. As adults, a third of them had an onset of psychosis! [. . .] So, it brings a self-dialectic process, because I really feel that it will turn into a bipolar disorder”. (7) A psychiatrist explained that outcome results from early intervention research must not be disclosed to parents. « I know that kids with dyspraxia awake researchers’ interest. But I just can’t say to parents: ‘‘research teams believe that there is 30% risk of psychosis onset during adolescence”! We may think it, we may conduct studies about it, but in daily work this is not possible. Any- how, I keep an eye on them, I follow them up. » (6) Psychosis risk research versus daily prognosis uncertainties Table 1. Participants. Interview number Sex Age Setting(s): Paris Region Drug prescription Aware of early intervention programs and center of expertise Interest in early intervention research Already worked in partnership with early detection centers Involvement in research: personal involvement or partnership with a research team in youth psychiatry 1 F 55 • Public youth psychiatry consultation center • Private practice psychoanalysis No Yes No No No 2 M 60 • Public consultation center for children Yes Yes No No Pharmacology history 3 M 35 • Student help • Public youth psychiatry consultation center No Yes No No No 4 M 70 • Public youth psychiatry consultation center • Private practice, psychoanalysis No Yes No No No 5 M 70 • Public youth psychiatry consultation center Yes Yes Yes No No 6 F 50 • Public center of expertise for language disorder. • Private practice of psychoanalysis No Yes Yes Yes Cohort of children with dyspraxia in order to assess psychosis onset rates in adolescence and young adulthood. 7 F 42 • Public youth psychiatry department of a University Hospital Center. Yes Yes Yes Yes Cohort of teens after a first bipolar episode or psychotic episode 8 M 32 • Public youth psychiatry department of University Hospital Center. Yes Yes No Yes Qualitative studies of suicide among teens 9 F 50 • Public youth psychiatry consultation center Yes Yes Yes Yes Qualitative studies about ADHD 10 M 40 • School-based residential psychiatry unit Yes Yes No Yes No 11 F 50 • School-based residential psychiatry unit Yes Yes Yes Yes No 12 F 28 • Public youth psychiatry consultation center. Yes Yes No No Pharmacological management strategies for resistant psychosis. https://doi.org/10.1371/journal.pone.0179849.t001 Table 1. Participants. criticize it. Thus, they are reluctant to refer their patients to early management centers where ARMS might be assessed. However, either trained or not, all participants provided their young patients with multiple months follow up without use of an At Risk Mental State category (ARMS) [20,21]. 1. Scales do not bring certitude. Participants were either enthusiastic about ARMS research or not. Half of them had already worked in partnership with an early detection center, for research or clinical purposes [Table 1]. Nevertheless, most psychiatrists did not use stan- dardized tools to assess prodromal conditions. Impossible to predict psychosis in daily work Detection: An inescapable question without an answer. All psychiatrists considered prognosis as an unavoidable question but they stressed the difficulty to remain informed of their young patients’ outcomes. « I would say that prognosis is always a question, but we have no answer. We receive no news, but is it because the young people recovered or is it because they are somewhere else?” « I would say that prognosis is always a question, but we have no answer. We receive no news, but is it because the young people recovered or is it because they are somewhere else?” (10) (10) 5 / 16 PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 Psychosis risk research versus daily prognosis uncertainties Some psychiatrists preferred to avoid this question but fail to do so. « It isn’t useful for me to imagine that a 15 years old teen may become schizophrenic. It is pointless. « It isn’t useful for me to imagine that a 15 years old teen may become schizophrenic. It is pointless. - Ok. But do you still wonder about his future or not? - Yes! Yes. » - Yes! Yes. » (2) Prevention: no proof of success. Interviewees expressed doubts that early intervention could really prevent the onset of psychosis. «—Is it possible to prevent psychosis onset? «—Is it possible to prevent psychosis onset? - (Laughing) Good question! I would be curious to hear other psychiatrists’ answers. (Seri- ous again) I don’t know. I don’t know. I don’t know. It would be hard to prove. » - (Laughing) Good question! I would be curious to hear other psychiatrists’ answers. (Seri- ous again) I don’t know. I don’t know. I don’t know. It would be hard to prove. » (8) Most psychiatrists actually consider that early intervention should be seen as a form of ter- tiary prevention (aiming at reducing permanent impairment) rather than a strategy of primary or secondary prevention (avoiding the onset of psychosis) [22]. Despite increasing waiting lists, the French mental health system has been designed to provide free and accessible primary care since 1960 [23]. In this context, it appears unethical to evaluate the efficacy of early inter- vention on patients with subdued symptoms through a comparative outcome study. PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 Three sources of uncertainty Psychiatrists’ impossibility to predict psychosis emerges from three sources of uncertainty. Medical judgment. Each case is an individual one: Outcome statistics do not allow reli- able predictions for a given individual. Psychiatrists’ uncertainty emerges from the limits of their own knowledge, the limits of medical science, and their difficulty to distinguish between both sources of uncertainty. «[Speaking about outcome after a first psychotic episode] There is one third, one third, one third [in reference to 3 possible outcomes: psychosis, recurrent acute psychotic episodes, and no mental trouble]. But—unless you know new studies—there is no clue to guess in which third is your patient”. (8) Feeling relieved by uncertainty: Uncertainty disclosure may be used as a way to manage teenagers and parents expectancies. “I tell parents that I am not a soothsayer! There are three outcomes, but there is no way to know how it will evolve” “I tell parents that I am not a soothsayer! There are three outcomes, but there is no way to know how it will evolve” (8) Uncertainty also supports psychiatrists’ curiosity toward their patients’ evolution, and relieves them from the burdening responsibility of an unreliable prophecy. “If you tell me what the magic formula is to say “this one will be psychotic”, I would be glad to have it! But it would also make the job rather boring. That is something interesting in our job. Not to know. » “If you tell me what the magic formula is to say “this one will be psychotic”, I would be glad to have it! But it would also make the job rather boring. That is something interesting in our job. Not to know. » (8) Adolescence process. Is it teenage rebellion or mental trouble? Psychiatrists acknowledge having difficulties to distinguish what may reflect adolescent unease and what may be a true psychiatric disorder. “It is hard to set thing apart, from what is teenage rebellion and what is a deep psychic crisis. We are always providing a counterweight on the one side or on the other side ” “It is hard to set thing apart, from what is teenage rebellion and what is a deep psychic crisis. It is hard to set thing apart, from what is teenage rebellion and what is a deep psychic crisis. « Can psychiatric care avert psychosis onset? It is important to be far-sighted, but it is difficult.» (8). (8). « Can psychiatric care avert psychosis onset? « Can psychiatric care avert psychosis onset? - What a question! I don’t know. One can assume that without proper care—I don’t know if they would really develop schizophrenia—but they would surely have a psychological or cognitive impairment. Without care at all, I will never know. It would mean venturing a study following-up persons who receive care, and the same number who not receive any care, and assess the natural course. That is questionable, ethically. » - What a question! I don’t know. One can assume that without proper care—I don’t know if they would really develop schizophrenia—but they would surely have a psychological or cognitive impairment. Without care at all, I will never know. It would mean venturing a study following-up persons who receive care, and the same number who not receive any care, and assess the natural course. That is questionable, ethically. » (10) No theory spares worries about the future. Some participants spontaneously explained their reluctance toward predictive approaches by a theoretical choice such as psychoanalysis or a adolescent psychiatrist’s view. Nevertheless, this attitude did not spare them worries about the future of their young patients, and failed to provide an unequivocal answer to the prognos- tic question. « As a psychotherapist I should break free from [the prognosis] question to elaborate the sense of what is happening to him. But having in mind that he might be somehow delirious [. . .] makes me suspicious of what may happen. I referred him to a colleague for a prescrip- tion so as to break free from this problem. But, of course, I was not relieved! » « As a psychotherapist I should break free from [the prognosis] question to elaborate the sense of what is happening to him. But having in mind that he might be somehow delirious [. . .] makes me suspicious of what may happen. I referred him to a colleague for a prescrip- tion so as to break free from this problem. But, of course, I was not relieved! » (1) 6 / 16 PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 Psychosis risk research versus daily prognosis uncertainties « The adolescent psychiatrist attitude is to face teenagers’ immediate shifts. It is different from the attitude of an adult psychiatrist. [The long-term risk] is obviously a question when we stop and think about it, but not in our daily work. PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 Three sources of uncertainty Either it wasn’t schizophrenia or they managed to recover. That is harmful. If we have a doubt it is better not to mention it.” (10) Thus, the uncertainties surrounding medical practice, adolescence and psychosis shape youth psychiatrists’ impossibility to predict psychosis. Thus, the uncertainties surrounding medical practice, adolescence and psychosis shape youth psychiatrists’ impossibility to predict psychosis. Three sources of uncertainty We are always providing a counterweight on the one side or on the other side.” (10) (10) The adolescence processappears in between instability and self-construction.Youth psychia- trists express the feeling that teenagers are moving on an irretrievable trajectory that can be improved through psychiatric support. PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 7 / 16 PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 Psychosis risk research versus daily prognosis uncertainties « One gets structured, during adolescence and young adulthood by symptoms and mental suffering. When you work with teens you have this feeling that your influence allows them not to switch on the wrong side”. (4) Nevertheless, daily practice consists in dealing with immediate changes that make every short or long term outcome unpredictable. « When you think of something, the teen has already changed! » (8) Psychosis uncertainties. A historical vision of psychosis as a lifelong mental and social trouble shapes psychiatrists reluctance to anticipate psychotic transition. «One may be afraid to anticipate an illness that you do not still have. It is a serious problem, severe, resistant, with heavy treatments, side effects for sure, that impacts social and profes- sional life. It will be a lifelong problem, and he is only a teen!” «One may be afraid to anticipate an illness that you do not still have. It is a serious problem, severe, resistant, with heavy treatments, side effects for sure, that impacts social and profes- sional life. It will be a lifelong problem, and he is only a teen!” (12) Psychiatrists face a paradox. The success of early intervention would contradict the vision of this mental trouble as a social impairment. « Persons that turn out « normal » again a few years later, I am forced to consider that I was mistaken about a schizophrenia early diagnosis. » « Persons that turn out « normal » again a few years later, I am forced to consider that I was mistaken about a schizophrenia early diagnosis. » (5) Both eventualities of false positive patients and cases of successful care lead psychiatrists to avoid prediction and refuse to disclose an ARMS status. Both eventualities of false positive patients and cases of successful care lead psychiatrists to avoid prediction and refuse to disclose an ARMS status. “How many teens have been labeled schizophrenics? Time goes by and reveals that they aren’t schizophrenics. PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 The challenge of individual psychosis prediction The first source of uncertainty mentioned by participants refers to medical judgment and is consistent with the sociological analysis of medicine. Fox argued that learning to cope with the uncertainty of medical practice is a professional norm that is assimilated early in the curricu- lum. She distinguished three sources of uncertainty: the limits of a physician’s knowledge, the limits of medical science, and the inability of the physician to distinguish between those two sources of uncertainty [25,26]. Freidson and Hunter argued that medicine is taught as a sci- ence of individuals. Each clinical case is unique and therefore uncertain [27,28]. According to Light, medical trainees learn to control uncertainty through specialization, involvement in schools of thought, clinical experience, and growing autonomy [29]. Thus, claiming to belong to a school of thought such as psychoanalysis or youth psychiatry could merely be way to cope with uncertainty. Dealing with serious diseases, prognosis uncertainty can be functional, that is used by doctors in order to avoid distress reactions from patients and their relatives [30] and avoid being held responsible for the patient’s outcome [8]. In that sense, a prognosis disclosure is a too risky commitment. This opinion is expected to persist over some period of time, to account for the psychiatrist’s “consistent behavior”. According to Becker, commitments come into being when a person, by making a side bet, links extraneous interests with a consistent line of activity [31]. Side bets are often a consequence of the person’s participation in social organizations. In daily work, a person sometimes finds that he has made side bets constraining his present activity because the existence of general cultural expectations provides penalties for those who violate them [31]. For instance, the cultural expectation about the behavior account- ing for a practitioner’s trustworthiness is different from the expectation accounting for the trustworthiness of a researcher. People feel that a practitioner ought not to change his opinion too often and that one who does is inexperienced and untrustworthy [8]. On the contrary, a researcher’s shifting views on a subject might account for his commitment through his consis- tency in improving his study design. Thus, a practitioner will avoid prognosis disclosure, instead of sharing his worries about a psychosis onset to a young patient and then changing his opinion after a second appointment. Functional uncertainty is thus used by doctors in order to diminish their own level of commitment. Discussion According to participants, neither the results of research, standardized instruments nor clinical judgment enable the prediction of psychosis before its onset. The gap between ARMS research and daily work is related to the limitations of preventive instruments, as well as that of schools of thought. For a given teenager, detection and prevention efficiency remain impossible to prove. Nevertheless, neither psychoanalysis nor child development theories—both focusing on a present timeframe in order to support teenagers’ elaboration and positive identity construc- tion [24]–spare psychiatrists worries about their young patients future. Finally, individual psy- chosis prediction failure appears related to the many uncertainties surrounding medical PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 8 / 16 Psychosis risk research versus daily prognosis uncertainties practice, the adolescence process, and psychosis itself. In the following sections, we propose to discuss participants’ uncertainties through two ideas. First, individual prognosis is a challenge inherent to medical practice. Second, declared interest for or reluctance toward predictive approaches may be shaped by health systems. PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 Psychosis risk research versus daily prognosis uncertainties adult population, psychotic-like experiences are strongly correlated with distress, depression and poor functioning [41]. Participants’ third source of uncertainty was related to psychosis diagnosis and course. First, we asked questions focusing on psychosis but participants’ answers focus on schizophre- nia (in French “schizophre´nie”) instead of psychosis (psychose). According to the Grounded Theory, this is neither a methodological problem, nor a translation mistake, but a meaningful result. The use of schizophrenia as a synonym for psychosis enlightens participants’ contempo- rary representation of psychosis as an equivalent of schizophrenia. The schizophrenia label, if still used as a reliable research category [42,43] is increasingly contested in order to reduce stigma [44] and account for a complex and poorly understood etiology [45,46]. The Ultra High Risk of psychosis (UHR) low prediction accuracy (15% to 25%) [47], high rates of false positive identifications (from 50% to 84%) [48,49] and difficulties to evaluate if early treat- ments improve long-term outcomes are stressed as current research challenges [50–54]. Research teams believe that the risk of psychosis onset during adolescence is far lower than 30% when SIPS or CARMS is applied in the general community [49]. Authors attribute this low predictive value to low prevalence of the psychosis risk syndrome in a general adolescent clinical population [55]. Thus, given the potential stigma associated to a Psychosis Risk syn- drome [56] and its need to be further validated, it was not included in the DSM-V [57]. Sec- ond, participants expressed a contradiction between the practice of a probabilistic judgment in early diagnosis, due to the fact that psychosis diagnosis is based on a retrospective duration cri- teria [58]. Third, our results show that the vision of psychosis as a disastrous life-long trouble [59,60] refrains psychiatrists’ involvement in preventive approaches. Despite activism by for- mer patients and patient advocates who have argued that psychosis did not prevent persons to live meaningful lives and to maintain a social role in their community, as well as scientific evi- dences that the course of schizophrenia is not always negative [9–12,61,62], schizophrenia’s major economic costs and duration shapes the idea that “the onset of psychotic illness represents potential personal disaster in the life-course of an individual” [63]. Thus, interviewed psychia- trists extended the deadline before disclosing such a dreadful perspective. However, if the pri- mary outcome of interest in at-risk research was the development of psychotic disorder— whereby patients are categorized as either having ‘transitioned’ or ‘not transitioned’–recent research suggest that ‘non transitioned’ persons may have a poorer quality of life [64,65]. More than attenuated psychotic symptoms (APS), social and functioning difficulties as well as depressive symptoms can be the highest sources of distress leading UHR patients to seek help [66]. Thus, the term ‘outcome’ might be broadened to incorporate non-psychotic diagnoses, functioning and negative symptoms [67]. PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 The challenge of individual psychosis prediction The second source of uncertainty mentioned by the participants to this study was the immediacy and unpredictability of teenagers’ symptoms. The adolescent period is seen as a social, hormonal, neurological, and psychological storm both by public opinion and by health professionals [32,33]. As early as in 1958, Anna Freud famously suggested that calm teenagers may hide distressful emotions: “being normal during the adolescence period is abnormal” [34]. The participants in our study argued that they were not always able to distinguish adolescent unease or rebellion from subdued psychotic symptoms. Interviewees’ vision of ado- lescence as an unpredictable process combining daily mood instability and social skills devel- opment is supported by neurosciences [35,36]. Teenagers new access to abstract thinking, if formerly stressed by child development psychology [37] is now supported by brain imagery studies revealing a neuronal network reconfiguration through synaptic trimming [38] that extends into the second and third decades of life [39]. Another difficulty is related to the fact that the incidence of positive psychotic experiences in the general population is 100 times greater than the incidence of psychotic disorders [40]. Moreover, in the adolescent and young PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 9 / 16 Health systems beyond the research/clinic dichotomy Interactionism in sociology focuses on the way that people act and on the reasons they give to justify their action [68]. In this perspective, a meaning does not need to be “true” to be effec- tive. The meaning that people give to a thing or an event determines its symbolic reality, which has the power to induce a social effect. Which reasons can be used by our participants to support their views? Even if they know statistical data related to psychosis onset, in the end psychiatrists make decisions according to their clinical sense. This “in-between” strategy including both rational and non-rational strate- gies has been proven to be efficient in risk-management strategies [69]. Our results show that participants do not expect that early diagnosis tools improve the actual care provided. They legitimize their reluctance toward ARMS assessment by the clinic/research dichotomy. For instance, two reasons are used by our participants to avoid the referral of their young patients PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 10 / 16 Psychosis risk research versus daily prognosis uncertainties to assessment centers: first, it is impossible to predict an individual outcome; second, it is impossible to know if psychosis can be prevented in an individual. However, researchers of the ARMS field already agree with those critics [49]: first, ARMS assessment instruments aim at determining an ARMS, not predicting psychosis in an individual. Second, early interventions for ARMS individuals aim at improving functional outcome at group level. Nevertheless, “valid” or not in a scientific meaning, these reasons induce a real social effect: our participants’ reluctance to refer their young patients for ARMS standardized assessment. According to the Grounded Theory, this confusion does not reveal a methodological mistake or participants’ lack of perspective, but a meaningful result. Moreover, we will argue in the following section that participants’ inconspicuous risk management might as well be understood considering the characteristics of the French health system. How do our participants actually act? When they suspect a psychosis onset, interviewees start an inconspicuous risk management: multiple months follow up of this fuzzy clinical state. We suggest that this strategy may be influenced by the organization of youth mental health ser- vices in France. In this country 77% of mental health care is provided by the public system with a universal costs coverage [70]. A diagnosis of risk is not necessary in order to obtain reimbursement of mental health costs. Health systems beyond the research/clinic dichotomy Thus, psychiatrists use their subjective judgment to start a discreet follow-up. As early as in 1941, Ru¨mke described the “praecox feeling” as a feel- ing of unease emanating in the interviewer that reflects the detachment of the patient and the failure of an ‘affective exchange’ [71]. Praecox feeling reliability has mainly been evaluated among persons with an ongoing psychosis. Compared with the standardized diagnostic classi- fication the precision of the intuitive reasoning appears remarkably high [72–74]. On the con- trary, in a U.H.R. population, Nelson and Yung showed that the clinical impression of an incipient psychosis—that is, a clinical judgment that a particular patient may soon progress to a full-threshold disorder—is not sufficient for predicting a psychosis outcome and may lead physicians to improper antipsychotic medication [75]. This result stresses the need to design more adequate follow ups for young people. Youth psychiatry (child and adolescent) services usually stop following patients when they reach 18 years of age and are then referred to adult services. The communication between those services remains limited both for clinical and for research purposes. Today, despite psychosis peak onset in late adolescence—early adulthood [76], only few youth psychiatry departments are designed for following up young patients until 25 to 30 years. The participants to our study usually did not receive news from their patients after they had been referred. The lack of outcome studies following young patients from child to adult departments and of services specially designed for persons aged 15–30, increases the youth psychiatrists’ challenge to imagine young patients’ evolution after their 18s. Study limitations and implications: Rationale for a comparison of local mental health system changes If qualitative methods’ validity is increasingly acknowledged in medicine, the Grounded The- ory (GT) remains rarely known in the medical field. If Interpretative Phenomenological Anal- ysis (IPA) is the dominant method increasingly used in psychological studies—and previously employed by our team [77]–its’ main difficulty is to develop the analysis to a sufficient inter- pretative level [78]. IPA aims to understand the experiences (phenomenology) and meaning- making activities (interpretation) of the research participant [18]. The analyst attempts to make sense of the participants’ interpretation of their own experience, thus creating a double hermeneutic [79]. Nevertheless, improving the interpretation level can be facilitated by bor- rowing techniques from the GT [80]. Beyond the individual psychological experience PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 11 / 16 Psychosis risk research versus daily prognosis uncertainties described by IPA, the GT emphasizes its particular societal, cultural and political context. That is, participants’ views convey some knowledge about beliefs and practices shaped by profes- sional norms and institutions’ organization. IPA is better known than GT in the medical field due to the historical fact that most mental health qualitative research has been designed by psychologists in order to grasp individual experiences [81]. In the present context of positive mental health, Grounded Theory provides a particularly relevant approach for qualitative researches assessing the local impact of contemporary health system changes. The sampling strategy was to encounter diverse range of youth psychiatrists working in dif- ferent settings and being either actively involved in research or not [17]. However, if psychia- trists had distinctive clinical practices and attitudes toward research, they were unanimous about their impossibility to commit in prognostications in their daily work. Thus, saturation was rapidly reached. A validity criterion of qualitative studies is to expose results of the analysis to participants. Findings were directly communicated to four participants and five oral com- munications were addressed to more than 70 youth psychiatrists’ who agreed with our results (oral communications in the department meetings of three hospitals Cochin, Pitie´-Salpêtrière, and Avicenne (Paris Region), the annual conference of de French Society of Child and Adoles- cent Psychiatry (SFPEADA) in Lyon, May 2016, the annual conference of French Society for Psychiatric Information (SIP) in Bruxelles, September 2016). While it is not possible to gener- alize from such a small scale study, the opinion reported here may reflect the perspectives of a significant segment of French youth psychiatrists. Conclusion This study stressed the gap between the psychosis risk research and adolescent psychiatrists daily prognosis uncertainties [83]. Psychiatrists’ reluctance toward early psychosis detection was shaped by three difficulties: first the theoretical gap between research and practice; second their impossibility to make reliable prognoses; and third, their uncertainties relating to medical judgment, adolescence and the nature of psychosis. If our participants explained their reluc- tance toward ARMS assessment by the clinic/research dichotomy, their inconspicuous risk management appears merely supported by the French health system facilities. They allow free follow ups that are not conditional on ARMS assessment. Improving the early management of child and adolescent mental health disorders [84] is a necessity that increases the need to acknowledge uncertainty [85]. Meanwhile, daily predictive practices appear shaped by distinc- tive cultural, societal and political contexts, such as mental health services design and costs coverage. Study limitations and implications: Rationale for a comparison of local mental health system changes This study is first step to provide an account of early interventions implementation. The W.H.O. argues that given their historical and con- ceptual diversity, the efficiency of the mental health policies and practices in different coun- tries is difficult to compare in an evidence based perspective [82]. Using the GT in different countries would offer a qualitative comparison of young people access to mental health care and a particularly relevant insight of psychosis early management implementation in psychiat- ric services. Supporting information S1 Appendix. A supporting information file with relevant excerpts. (DOCX) Author Contributions Conceptualization: LB. Conceptualization: LB. 12 / 16 PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 Psychosis risk research versus daily prognosis uncertainties Data curation: LB. Formal analysis: LB NH. Funding acquisition: NH. Investigation: LB. Methodology: LB NH. Project administration: NH. Validation: LB NH MRM BF. Visualization: LB. Writing – original draft: LB. Writing – review & editing: LB. Data curation: LB. Formal analysis: LB NH. Funding acquisition: NH. Investigation: LB. Methodology: LB NH. Project administration: NH. Validation: LB NH MRM BF. Visualization: LB. Writing – original draft: LB. Writing – review & editing: LB. Data curation: LB. Formal analysis: LB NH. Funding acquisition: NH. Investigation: LB. Methodology: LB NH. Project administration: NH. Validation: LB NH MRM BF. Visualization: LB. Writing – original draft: LB. Writing – review & editing: LB. Data curation: LB. Formal analysis: LB NH. Funding acquisition: NH. Investigation: LB. Methodology: LB NH. Writing – original draft: LB. Writing – review & editing: LB. Writing – review & editing: LB. References 1. McGorry P, Bates T, Birchwood M. Designing youth mental health services for the 21st century: exam- ples from Australia, Ireland and the UK. Br J Psychiatry. 2013; 202: s30–s35. 2. Yung AR, Phillips LJ, McGorry PD, McFarlane CA, Francey S, Harrigan S, et al. Prediction of psychosis: A step towards indicated prevention of schizophrenia. Br J Psychiatry. 1998; 172: 14–20. 3. Yung AR, McGorry PD. The prodromal phase of first-episode psychosis: past and current conceptuali- zations. Schizophr Bull. 1996; 22: 353–370. PMID: 8782291 4. Cabut S. Nouveaux regards sur la schizophre´nie. Le Monde. juin 2015. 5. Carey B. Severe Mental Illness Found to Drop in Young, Defying Perceptions. NY-Times. mai 2015. http://www.nytimes.com/2015/05/21/health/reduction-is-found-in-severe-mental-illness-among-the- young.html?emc=edit_th_20150521&nl=todaysheadlines&nlid=49601210&_r=1. Accessed 21 May 2015. 6. Rosier F. Pre´dire la schizophre´nie par ordinateur—31 aouˆt 2015. Le Monde. 2015. 7. Oppetit A, Bourgin J, Martinez G, Kazes M, Mam-Lam-Fook C, Gaillard R, et al. The C’JAAD: a French team for early intervention in psychosis in Paris. Early Interv Psychiatry. 2016; n/a–n/a. 8. Christakis NA. Death Foretold: Prophecy and Prognosis in Medical Care. University of Chicago Press; 2001. 9. Kaplan RM. Being Bleuler: the second century of schizophrenia. Australas Psychiatry. 2008; 16: 305– 311. https://doi.org/10.1080/10398560802302176 PMID: 18781458 10. Fowler R, McCabe M, Cadoret R, Winokur G. The validity of good prognosis schizophrenia. Arch Gen Psychiatry. 1972; 26: 182–185. PMID: 5060405 11. Strauss JS, Carpenter WTJ. The prediction of outcome in schizophrenia: I. characteristics of outcome. Arch Gen Psychiatry. 1972; 27: 739–746. PMID: 4637891 12. Zipursky RB, Reilly TJ, Murray RM. The Myth of Schizophrenia as a Progressive Brain Disease. Schi- zophr Bull. 2013; 39: 1363–1372. https://doi.org/10.1093/schbul/sbs135 PMID: 23172002 13. Corbin J, Strauss A. Basics of qualitative research: Techniques and procedures for developing grounded theory. Sage. 2014. 14. Glaser BG, Strauss A. The discovery of the Grounded Theory: strategies for qualitative research. Aldine. Chicago; 1967. 15. Charmaz K, Mitchell R. Grounded Theory in Ethnography. Handbook of ethnography. London; 2001. pp. 160–174. 16. Whitley R. Introducing psychiatrists to qualitative research: a guide for instructors. Acad Psychiatry. 2009; 33: 252–255. https://doi.org/10.1176/appi.ap.33.3.252 PMID: 19574526 17. Mays N, Pope C. Qualitative research: rigour and qualitative research. Bmj. 1995; 311: 109–112. 18. Smith JA, Osborn M. Interpretative Phenomenological Analysis. Qualitative psychology: a practical guide to research met hods. Smith JA, editors. London: Sage Publications; 2008. PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 13 / 16 Psychosis risk research versus daily prognosis uncertainties 19. References Fusar-Poli P, Cappucciati M, Rutigliano G, Lee TY, Beverly Q, Bonoldi I, et al. Towards a Standard Psy- chometric Diagnostic Interview for Subjects at Ultra High Risk of Psychosis: CAARMS versus SIPS. Psychiatry J. 2016; 2016: 1–11. 20. McGorry PD, Yung AR, Phillips LJ, Yuen HP, Francey S, Cosgrave EM, et al. Randomized Controlled Trial of Interventions Designed to Reduce the Risk of Progression to First-Episode Psychosis in a Clini- cal Sample With Subthreshold Symptoms. Arch Gen Psychiatry. 2002; 59: 921–928. PMID: 12365879 21. Addington J, Cornblatt BA, Cadenhead KS, Cannon TD, McGlashan TH, Perkins DO, et al. At Clinical High Risk for Psychosis: Outcome for Nonconverters. Am J Psychiatry. 2011; 168: 800–805. https://doi. org/10.1176/appi.ajp.2011.10081191 PMID: 21498462 22. Caplan G. Principles of preventive psychiatry. Oxford, England: Basic Books; 1964. 23. Circulaire du 15 mars 1960, relative au programme d’organisation et d’e´quipement des de´partements en matière de lutte contre les maladie s mentales. Mar 15, 1960. 24. Kestemberg E. L’identite´ et l’identification chez les adolescents. Psychiatr Enfant. 1962; 5: 441. 25. Fox RC. Training for uncertainty. The student-physician Introductory studies in the sociology of medical education. Cambridge, MA: Harvard University Press; 1957. 26. Fox RC. Medical Uncertainty Revisited. The Handbook of Social Studies in Health and Medicine. Thou- sand Oaks. London: SAGE; 2000. 27. Hunter KM. Doctors’ Stories: The Narrative Structure of Medical Knowledge. Princeton University Press; 1991. 28. Freidson E. Profession of Medicine. Dodd, Mead. New York; 1970. 29. Light D. Uncertainty and Control in Professional Training. J Health Soc Behav. 1979; 20: 310. PMID: 541485 30. Davis F. Uncertainty in Medical Prognosis Clinical and Functional. Am J Sociol. 1960; 66: 41–47. 31. Becker HS. Notes on the concept of commitment. Am J Sociol. 1960; 32–40. 32. Arnett JJ. Adolescent Storm and Stress, Reconsidered. Am Psychol. 1999; 33. Hall WD, Patton G, Stockings E, Weier M, Lynskey M, Morley KI, et al. Why young people’s substance use matters for global health. Lancet Psychiatry. 2016; 3: 265–279. https://doi.org/10.1016/S2215- 0366(16)00013-4 PMID: 26905482 34. Freud A. Adolescence. Psychoanal Study Child. 1958; 255–278. PMID: 13614588 35. Blakemore S-J. The social brain in adolescence. Nat Rev Neurosci. 2008; 9: 267–277. https://doi.org/ 10.1038/nrn2353 PMID: 18354399 36. Mills KL, Lalonde F, Clasen LS, Giedd JN, Blakemore S-J. Developmental changes in the structure of the social brain in late childhood and adolescence. Soc Cogn Affect Neurosci. 2014; 9: 123–131. https://doi.org/10.1093/scan/nss113 PMID: 23051898 37. Piaget J. Psychologie de l’intelligence. References Deconstructing the Psychosis Risk Syndrome: Moving the Field of Preven- tion Forward. JAMA Psychiatry. 2016; 73: 105. https://doi.org/10.1001/jamapsychiatry.2015.2454 PMID: 26720422 51. McGlashan TH, Zipursky RB, Perkins D. Randomized, double-blind trial of olanzapine versus placebo in patients prodromally symptomatic for psychosis. Am J Psychiatry. 2006; 163: 790–799. https://doi. org/10.1176/ajp.2006.163.5.790 PMID: 16648318 52. Morrison AP. Morrison AP, French P, Parker S, et al. Three-year follow-up of a random- ized controlled trial of cognitive therapy for the prevention of psychosis in people at ultrahigh risk. Schizophr Bull. 2007; 33(3):682–687. https://doi.org/10.1093/schbul/sbl042 Schizophr Bull. 2007; PMID: 16973786 53. Phillips LJ, Mc Gorry PD, Yuen HP. Medium term follow-up of a randomized controlled trial of interven- tions for young people at ultra high risk of psychosis. Schizophr Res. 2007; 96: 25–33. https://doi.org/ 10.1016/j.schres.2007.05.018 PMID: 17611080 54. Yung AR, Phillips LJ, Nelson B, Francey SM, PanYuen H, Simmons MB, et al. Randomized controlled trial of interventions for young people at ultra high risk for psychosis: 6-month analysis. J Clin Psychia- try. 2010; 72: 430–440. https://doi.org/10.4088/JCP.08m04979ora PMID: 21034687 55. Yung AR, Nelson B, Stanford C, Simmons MB, Cosgrave EM, Killackey E, et al. Validation of “prodro- mal” criteria to detect individuals at ultra high risk of psychosis: 2 year follow-up. Schizophr Res. 2008; 105: 10–17. https://doi.org/10.1016/j.schres.2008.07.012 PMID: 18765167 56. Yang LH, Wonpat-Borja AJ, Opler MG, Corcoran CM. Potential stigma associated with inclusion of the psychosis risk syndrome in the DSM-V: An empirical question. Schizophr Res. 2010; 120: 42–48. https://doi.org/10.1016/j.schres.2010.03.012 PMID: 20399610 57. Yung AR, Nelson B, Thompson AD, Wood SJ. Should a “Risk Syndrome for Psychosis” be included in the DSMV? Schizophr Res. 2010; 120: 7–15. https://doi.org/10.1016/j.schres.2010.03.017 PMID: 20382506 58. DSM-5. Diagnostic and Statistical Manual of Mental Disorders 5th Ed. American Psychiatric Associa- tion; 2013. 59. Lanteri-Laura G. La chronicite´ dans la psychiatrie moderne franc¸aise. Note d’histoire the´orique et sociale. Ann Hist Sci Soc. 1972; 27: 548–568. 60. Kraepelin E. Compendium der Psychiatrie. Leipzig; 1883. 61. Fisher M, Holland C, Subramaniam K, Vinogradov S. Neuroplasticity-Based Cognitive Training in Schizophrenia: An Interim Report on the Effects 6 Months Later. Schizophr Bull. 2010; 36: 869–879. https://doi.org/10.1093/schbul/sbn170 PMID: 19269924 62. Fisher M, Loewy R, Carter C, Lee A, Ragland JD, Niendam T, et al. Neuroplasticity-Based Auditory Training Via Laptop Computer Improves Cognition in Young Individuals With Recent Onset Schizophre- nia. Schizophr Bull. 2014; 63. References A. Colin. Paris; 1967. 37. Piaget J. Psychologie de l’intelligence. A. Colin. Paris; 1967. 38. Dennis EL, Jahanshad N, McMahon KL, de Zubicaray GI, Martin NG, Hickie IB, et al. Development of Brain Structural Connectivity between Ages 12 and 30: A 4-Tesla Diffusion Imaging Study in 439 Ado- lescents and Adults. NeuroImage. 2013; 64: 671–684. https://doi.org/10.1016/j.neuroimage.2012.09. 004 PMID: 22982357 39. Steinberg L. Risk taking in adolescence new perspectives from brain and behavioral science. Curr Dir Psychol Sci. 2007; 16: 55–59. 40. Hanssen M, Bak M, Bijl R, Vollebergh W, Van Os J. The incidence and outcome of subclinical psychotic experiences in the general population. Br J Clin Psychol. 2005; 44: 181–191. https://doi.org/10.1348/ 014466505X29611 PMID: 16004653 41. Armando M, Nelson B, Yung AR, Ross M, Birchwood M, Girardi P, et al. Psychotic-like experiences and correlation with distress and depressive symptoms in a community sample of adolescents and young adults. Schizophr Res. 2010; 119: 258–265. https://doi.org/10.1016/j.schres.2010.03.001 PMID: 20347272 42. Jablensky A. The 100-year epidemiology of schizophrenia. Schizophr Res. 1997; 28: 111–125. PMID: 9468347 43. Ripke S, O’Dushlaine C, Chambert K, Moran JL, Ka¨hler AK, Akterin S, et al. Genome-wide association analysis identifies 13 new risk loci for schizophrenia. Nat Genet. 2013; 45: 1150–1159. https://doi.org/ 10.1038/ng.2742 PMID: 23974872 44. Lasalvia A, Penta E, Sartorius N, Henderson S. Should the label “schizophrenia” be abandoned? Schi- zophr Res. 2015; 162: 276–284. https://doi.org/10.1016/j.schres.2015.01.031 PMID: 25649288 45. Gaebel W, Zielasek J. Schizophrenia in 2020: Trends in diagnosis and therapy. Psychiatry Clin Neu- rosci. 2015; 69: 661–673. https://doi.org/10.1111/pcn.12322 PMID: 26011091 14 / 16 PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 Psychosis risk research versus daily prognosis uncertainties 46. Gur RE, Keshavan MS, Lawrie SM. Deconstructing Psychosis With Human Brain Imaging. Schizophr Bull. 2007; 33: 921–931. https://doi.org/10.1093/schbul/sbm045 PMID: 17548845 47. Fusar-Poli, Cappucciati M, Borgwardt S, Woods SW, Addington J, Nelson B, et al. Heterogeneity of Psychosis Risk Within Individuals at Clinical High Risk: A Meta-analytical Stratification. JAMA Psychia- try. 2016; 73: 113. https://doi.org/10.1001/jamapsychiatry.2015.2324 PMID: 26719911 48. Correll CU, Hauser M, Auther AM, Cornblatt BA. Research in people with psychosis risk syndrome: a review of the current evidence and future directions. J Child Psychol Psychiatry. 2010; 51: 390–431. https://doi.org/10.1111/j.1469-7610.2010.02235.x PMID: 20214698 49. Corcoran CM, First MB, Cornblatt B. The psychosis risk syndrome and its proposed inclusion in the DSM-V: A risk–benefit analysis. Schizophr Res. 2010; 120: 16–22. https://doi.org/10.1016/j.schres. 2010.03.018 PMID: 20381319 50. Cornblatt BA, Carrio´n RE. PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 References Hosman CMH, Jane´ Llopis E, Saxena S, World Health Organization, Department of Mental Health and Substance Abuse, Prevention Research Centre (Netherlands). Prevention of mental disorders: effec- tive interventions and policy options : summary report. Geneva: World Health Organization; 2004. 64. Fusar-Poli P, Rocchetti M, Sardella A, Avila A, Brandizzi M, Caverzasi E, et al. Disorder, not just state of risk: meta-analysis of functioning and quality of life in people at high risk of psychosis. Br J Psychiatry. 2015; 207: 198–206. https://doi.org/10.1192/bjp.bp.114.157115 PMID: 26329563 65. Lin A, Wood SJ, Nelson B, Brewer WJ, Spiliotacopoulos D, Bruxner A, et al. Neurocognitive predictors of functional outcome two to 13 years after identification as ultra-high risk for psychosis. Schizophr Res. 2011; 132: 1–7. https://doi.org/10.1016/j.schres.2011.06.014 PMID: 21763109 66. Rapado-Castro M, McGorry PD, Yung A, Calvo A, Nelson B. Sources of clinical distress in young peo- ple at ultra high risk of psychosis. Schizophr Res. 2015; 165: 15–21. https://doi.org/10.1016/j.schres. 2015.03.022 PMID: 25890793 15 / 16 PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 Psychosis risk research versus daily prognosis uncertainties 67. Lin A, Nelson B, Yung AR. ‘At-risk’ for psychosis research: where are we heading? Epidemiol Psychiatr Sci. 2012; 21: 329–334. https://doi.org/10.1017/S2045796012000388 PMID: 22846110 68. Glaser BG, Strauss AL. Awareness Contexts and Social Interaction. Am Sociol Rev. 1964; 29: 669– 679. 69. Zinn JO. Heading into the unknown: Everyday strategies for managing risk and uncertainty. Health Risk Soc. 2008; 10: 439–450. 70. Les comptes de la Se´curite´ Sociale. Etat des lieux de l’offre de soins en psychiatrie. 2014 pp. 116–119. 71. Ru¨mke HC. The nuclear symptom of schizophrenia and the praecoxfeeling. Hist Psychiatry. 1941; 1: 331–341. 72. Varga S. Vulnerability to psychosis, I-thou intersubjectivity and the praecox-feeling. Phenomenol Cogn Sci. 2013; 12: 131–143. 73. Carpenter WT Jr., Strauss JS, Muleh S. Are there pathognomonic symptoms in schizophrenia?: An empiric investigation of schneider’s first-rank symptoms. Arch Gen Psychiatry. 1973; 28: 847–852. PMID: 4707991 74. Grube M. Towards an Empirically Based Validation of Intuitive Diagnostic: Ru¨mke’s ‘Praecox Feeling’ across the Schizophrenia Spectrum: Preliminary Results. Psychopathology. 2006; 39: 209–217. https:// doi.org/10.1159/000093921 PMID: 16778451 75. Nelson B, Yung AR. Can clinicians predict psychosis in an ultra high risk group? Aust N Z J Psychiatry. 2010; 44: 625–630. https://doi.org/10.3109/00048671003620210 PMID: 20397780 76. Sadock BJ, Sadock VA, Ruiz P, Kaplan HI, editors. Kaplan & Sadock’s comprehensive textbook of psy- chiatry. 9. ed. Philadelphia, Pa.: Lippincott Williams & Wilkins; 2009. 77. PLOS ONE | https://doi.org/10.1371/journal.pone.0179849 July 19, 2017 References Benoit L, Harf A, Sarmiento L, Skandrani S, Moro MR. Shifting views but building bonds: narratives of internationally adopted children about their dual culture. Transcult Psychiatry. (corrected proof). 78. Hefferon K, Gil-Rodriguez E. Interpretative phenomenological analysis. Psychologist. 2011; 24: 756– 759. 79. Larkin M, Watts S, Clifton E. Giving voice and making sense in interpretative phenomenological analy- sis. Qual Res Psychol. 2006; 3: 102–120. 80. Strauss A, Corbin J. Basics of qualitative research. Sage. California; 1990. 81. Fossey E, Harvey C, McDermott F, Davidson L. Understanding and evaluating qualitative research*. Aust N Z J Psychiatry. 2002; 36: 717–732. https://doi.org/10.1046/j.1440-1614.2002.01100.x PMID: 12406114 82. World Health Organization. Policies and practices for mental health in Europe. [Internet]. Denmark: WHO : Stylus; 2008. http://site.ebrary.com/id/10268623 83. Benoit L. L’adolescent “fragile”: peut-on pre´dire en psychiatrie? Recherches. Paris; 2016. 84. Falissard B. Early detection of child and adolescent mental disorders: some elements of a necessary debate. Eur Child Adolesc Psychiatry. 2016; 25: 1041–1043. https://doi.org/10.1007/s00787-016-0906- 6 PMID: 27651078 85. Simpkin AL, Schwartzstein RM. Tolerating Uncertainty—The Next Medical Revolution? N Engl J Med. 2016; 375: 1713–1715. https://doi.org/10.1056/NEJMp1606402 PMID: 27806221 16 / 16
https://openalex.org/W2214390920
https://europepmc.org/articles/pmc2962143?pdf=render
Sinhala, Sinhalese
null
(3<i>R</i>,4<i>S</i>,5<i>S</i>)-4-Hydroxy-3-methyl-5-[(2<i>S</i>,3<i>R</i>)-3-methylpent-4-en-2-yl]tetrahydrofuran-2-one
Acta crystallographica. Section E
2,008
cc-by
4,393
(3R,4S,5S)-4-Hydroxy-3-methyl-5- [(2S,3R)-3-methylpent-4-en-2-yl]tetra- hydrofuran-2-one 1 restraint H-atom parameters constrained max = 0.14 e A˚ 3 min = 0.10 e A˚ 3 organic compounds b = 16.411 (3) A˚ c = 11.607 (2) A˚  = 95.46 (3) V = 1193.4 (4) A˚ 3 Z = 4 Mo K radiation  = 0.08 mm1 T = 291 (1) K 0.30  0.28  0.20 mm Data collection Nonius KappaCCD diffractometer Absorption correction: none 9263 measured reflections 2268 independent reflections 1228 reflections with I > 2(I) Rint = 0.026 Refinement R[F 2 > 2(F 2)] = 0.036 wR(F 2) = 0.080 S = 1.06 2268 reflections 262 parameters 1 restraint H-atom parameters constrained max = 0.14 e A˚ 3 min = 0.10 e A˚ 3 Acta Crystallographica Section E Structure Reports Online ISSN 1600-5368 Acta Crystallographica Section E Structure Reports Online ISSN 1600-5368 Mo K radiation  = 0.08 mm1 T = 291 (1) K 0.30  0.28  0.20 mm ISSN 1600-5368 Table 1 Received 30 May 2008; accepted 8 July 2008 D—H  A D—H H  A D  A D—H  A O2—H2  O3i 0.82 2.03 2.821 (3) 163 O20—H20  O30i 0.82 1.96 2.771 (3) 171 Symmetry code: (i) x þ 1; y; z. Key indicators: single-crystal X-ray study; T = 291 K; mean (C–C) = 0.005 A˚; R factor = 0.036; wR factor = 0.080; data-to-parameter ratio = 8.7. The title compound, C11H18O3, was synthesized to prove the relative configuration of the corresponding acyclic C1—C8 stereopentade. It crystallizes with two molecules in the asymmetric unit, which show only slight differences. The molecules are linked via O—H  O hydrogen bonds, resulting in two crystallographically independent chains of molecules propagating in the a-axis direction. The absolute configuration was known from the synthesis. Data collection: COLLECT (Nonius, 1998); cell refinement: DENZO and SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL-Plus (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003). Related literature Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HB2741). For related literature, see: Abraham, Ko¨rner & Hiersemann (2004); Abraham, Ko¨rner, Schwab & Hiersemann (2004); Corey & Snider (1972); Evans et al. (1981, 1999); Ko¨rner & Hiersemann (2006, 2007); Pollex & Hiersemann (2005). References Abraham, L., Ko¨rner, M. & Hiersemann, M. (2004). Tetrahedron Lett. 45, 3647–3650. Experimental Crystal data C11H18O3 Mr = 198.25 Monoclinic, P21 a = 6.2934 (13) A˚ Abraham, L., Ko¨rner, M., Schwab, P. & Hiersemann, M. (2004). Adv. Synth. Catal. 346, 1281–1294. Corey, E. J. & Snider, B. B. (1972). J. Am. Chem. Soc. 94, 2549–2550. Evans, D. A., Bartroli, J. & Shih, T. L. (1981). J. Am. Chem. Soc. 103, 2127– 2129. Evans, D. A., Miller, S. J., Lectka, T. & von Matt, P. (1999). J. Am. Chem. Soc. 121, 7559–7573. Ko¨rner, M. & Hiersemann, M. (2006). Synlett, pp. 121–123. Ko¨rner, M. & Hiersemann, M. (2007). Org. Lett. 9, 4979–4982. Nonius (1998). COLLECT. Nonius BV, Delft, The Netherlan Nonius (1998). COLLECT. Nonius BV, Delft, The Netherlands. ( ) Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, twinowski, Z. & Minor, W. (1997). Methods in Enzymolo Experimental Annika Becker, Markus Schu¨rmann, Hans Preut* and Martin Hiersemann Fakulta¨t Chemie, Technische Universita¨t Dortmund, Otto-Hahn-Strasse 6, 44221 Dortmund, Germany Correspondence e-mail: hans.preut@udo.edu Received 30 May 2008; accepted 8 July 2008 Key indicators: single-crystal X-ray study; T = 291 K; mean (C–C) = 0.005 A˚; R factor = 0.036; wR factor = 0.080; data-to-parameter ratio = 8.7. Fakulta¨t Chemie, Technische Universita¨t Dortmund, Otto-Hahn-Strasse 6, 44221 Dortmund, Germany Correspondence e-mail: hans.preut@udo.edu Table 1 Hydrogen-bond geometry (A˚ , ). D—H  A D—H H  A D  A D—H  A O2—H2  O3i 0.82 2.03 2.821 (3) 163 O20—H20  O30i 0.82 1.96 2.771 (3) 171 Symmetry code: (i) x þ 1; y; z. Table 1 Hydrogen-bond geometry (A˚ , ). Experimental ( ) Macromolecular Crystallography, Part A, edited by C. W. Carter Jr and R. M. Sweet, pp. 307–326, New York: Academic Press. R. M. Sweet, pp. 307 326, New York: Academic Press. Pollex, A. & Hiersemann, M. (2005). Org. Lett. 7, 5705–5708. Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. , pp , Pollex, A. & Hiersemann, M. (2005). Org. Lett. 7, 5705–5708. Sheldrick G M (2008) Acta Cryst A64 112 122 Pollex, A. & Hiersemann, M. (2005). Org. Lett. 7, 5705–570 Monoclinic, P21 a = 6.2934 (13) A˚ C11H18O3 Mr = 198.25 Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. ( ) Spek, A. L. (2003). J. Appl. Cryst. 36, 7–13. Becker et al. o1517 Acta Cryst. (2008). E64, o1517 Acta Cryst. (2008). E64, o1517 doi:10.1107/S1600536808021181 Comment The title compound, (I), was synthesized using a catalytic asymmetric Claisen rearrangement (Abraham et al., 2004a; Ab- raham et al. 2004b; Pollex & Hiersemann, 2005; Körner & Hiersemann, 2006; Körner & Hiersemann, 2007), a diastereose- lective reduction with K-Selectride (Körner & Hiersemann, 2006; Körner & Hiersemann, 2007), and an aldol addition un- der modified Evans conditions (Evans et al., 1981). In order to verify the relative configuration of the major diastereomer of the obtained aldol adduct (dr = 7/3), 4-(tert-butyldimethylsilyloxy)-3-hydroxy-2,5,6-trimethyloct-7-enoyl)-4-isopropyl- oxazolidin-2-one, (II), a γ-lactone, (I), was prepared by removal of the silyl protecting group (Corey et al., 1972) and sub- sequent in situ lactonization. Fig. 1 depicts the structure of the isolated major diastereomer (I). The configuration of the chiral C atoms in (I) can be attributed to the stereochemical course of the aldol addition (C3 R and C4 S), the diastereoselective reduction with K-Selectride (C5 S), and the catalytic asymmetric Claisen rearrangement (C2 S and C3 R) using the chiral Lewis acid [Cu{(S,S)-tert-Butyl-box}](H2O)2(SbF6)2 (Evans et al., 1999). There are two molecules of (I) in the asymmetric unit (Figs. 1 and 2) with similar conformations. In the crystal, the molecules interact via O—H···O hydrogen bonds (Table 1) to form two independent chains, both propagating in [100]. (3R,4S,5S)-4-Hydroxy-3-methyl-5-[(2S,3R)-3-methylpent-4-en-2-yl]tetrahydrofuran-2-one A. Becker, M. Schürmann, H. Preut and M. Hiersemann A. Becker, M. Schürmann, H. Preut and M. Hiersemann supplementary materials supplementary materials Acta Cryst. (2008). E64, o1517 [ doi:10.1107/S1600536808021181 ] Acta Cryst. (2008). E64, o1517 [ doi:10.1107/S1600536808021181 ] Experimental The title compound, (I), was synthesized from the corresponding anti-aldol adduct, (II), using tetrabutylammonium fluoride (TBAF) (Corey et al., 1972) for the removal of the silyl protecting group. The subsequent lactonization proceeded in situ. TBAF (1 M in tetrahydrofuran, 0.82 ml, 3.0 eq) was added to a solution of the diastereomeric mixture of (II) (dr = 7/3, 120 mg, 0.27 mmol, 1.0 eq) in dry tetrahydrofuran (2 ml) at 273 K. The mixture was stirred at 273 K for 15 min and then at 298 K for 30 min. The reaction was quenched by the addition of saturated aqueous NaHCO3 solution. The phases were separated, and the aqueous phase was extracted with CH2Cl2. The combined organic layers were dried over MgSO4 and concentrated under reduced pressure. Flash chromatography (isohexane/ethyl acetate 20/1 to 10/1) afforded (I) as a single diastereomer and additionally a mixture of (I) and the minor diastereomer with an overall yield of 72% (38.7 mg, 0.195 mmol) as colourless crystals. Single crystals of (I) were obtained by vapor diffusion recrystallization technique from isohexane and ethyl acetate to yield colourless cuboids: mp 412 K; Rf 0.33 (cyclohexane/ethyl acetate 2/1); 1H NMR (CDCl3, 400 MHz, δ): 0.84 (d, J = 7.0 Hz, 3H, (1)-H), 0.97 (d, J = 7.0 Hz, 3H, (3)'-H), 1.27 (d, J = 7.3 Hz, 3H, 3'-H), 1.85 (d, J = 4.8 Hz, 1H, –OH) overlapped by 1.89 (br. s), 2.19 (dqd, J = 10.6, 7.0, 3.0 Hz, 1H, (2)-H), 2.73 (dq, J = 4.8, 7.3 Hz, 1H, 3-H) overlapped by 2.62 - 2.72 (m, 1H, (3)-H), 4.07 (dd, J = 10.6, 3.0 Hz, 1H, 5-H), 4.37 (dd, J = 7.3, 4.8 Hz, 1H, 4-H), 5.03 (dd, 3J(E) = 17.0 Hz, 2J = 1.3 Hz, 1H, (5)-H), 5.04 (dd, 3J(Z) = 11.0 Hz, 2J = 1.3 Hz, 1H, (5)-H), 5.84 (ddd, 3J(E) = 17.0 Hz, 3J(Z) = 11.0 Hz, 3J = 6.3 Hz, 1H, (4)-H); 13C NMR (CDCl3, 100 MHz, δ): 8.4 (CH3), 9.7 (CH3), 12.3 (CH3), 35.7 (CH), 36.9 (CH), 42.7 (CH), 71.7 (CH), 84.3 (CH), 114.3 (CH2), 142.7 (CH), 178.4 (C); IR (cm-1): 3435(br, nm) (ν O—H, OH in H-bridges), 3085(w) 3020(w) (ν C—H, olefin), 2970(m) 2925(m) 2855(s) (νas,s C—H, CH2, CH3, CH), 1740(s) (ν sup-1 supplementary materials C=O, lactone), 1640(w) (ν C=C), 1465(m) (δas C—H, CH3, CH2), 1380(m) (δs C—H, CH3); Anal. Calcd. for C11H18O3: C, 66.6; H, 9.2; Found: C, 66.5; H, 9.3; [α]D20 +2.2 (c 0.472, CHCl3). Figures Fig. 1. : The molecular structure of molecule one of (I), with displacement ellipsoids for the non-hydrogen atoms shown at the 30% probability level. Fig. 2. : The molecular structure of molecule two of (I), with displacement ellipsoids for the non-hydrogen atoms shown at the 30% probability level. Refinement Anomalous dispersion was negligible and Friedel pairs were merged before refinement. The H atoms were geometrically placed (C—H = 0.93-0.98Å, O—H = 0.82Å) and refined as riding with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(methyl C, O). Figures Fig. 1. : The molecular structure of molecule one of (I), with displacement ellipsoids for the non-hydrogen atoms shown at the 30% probability level. Fig. 2. : The molecular structure of molecule two of (I), with displacement ellipsoids for the non-hydrogen atoms shown at the 30% probability level. (3R,4S,5S)-4-Hydroxy-3-methyl-5-[(2S,3R)- 3-methylpent-4-en-2-yl]tetrahydrofuran-2-one Figures F n F n Extinction correction: SHELXL97 (Sheldrick, 2008), Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 Primary atom site location: structure-invariant direct methods Extinction coefficient: 0.042 (4) Extinction coefficient: 0.042 (4) Extinction coefficient: 0.042 (4) (3R,4S,5S)-4-Hydroxy-3-methyl-5-[(2S,3R)- 3-methylpent-4-en-2-yl]tetrahydrofuran-2-one (3R,4S,5S)-4-Hydroxy-3-methyl-5-[(2S,3R)- 3-methylpent-4-en-2-yl]tetrahydrofuran-2-one Crystal data C11H18O3 F000 = 432 Mr = 198.25 Dx = 1.103 Mg m−3 Monoclinic, P21 Mo Kα radiation λ = 0.71073 Å Hall symbol: P 2yb Cell parameters from 9263 reflections a = 6.2934 (13) Å θ = 3.0–25.4º b = 16.411 (3) Å µ = 0.08 mm−1 c = 11.607 (2) Å T = 291 (1) K β = 95.46 (3)º Block, colourless V = 1193.4 (4) Å3 0.30 × 0.28 × 0.20 mm Z = 4 Data collection Nonius KappaCCD diffractometer 2268 independent reflections Radiation source: fine-focus sealed tube 1228 reflections with I > 2σ(I) Monochromator: graphite Rint = 0.026 Detector resolution: 19 vertical, 18 horizontal pixels mm-1 θmax = 25.4º T = 291(1) K θmin = 3.0º sup-2 supplementary materials 259 frames via ω–rotation (Δω=1%) and two times 120 s per frame (three sets at different κ–angles) scans h = −7→7 Absorption correction: none k = −19→19 9263 measured reflections l = −13→13 259 frames via ω–rotation (Δω=1%) and two times 120 s per frame (three sets at different κ–angles) scans h = −7→ Absorption correction: none k = −19 9263 measured reflections l = −13 259 frames via ω–rotation (Δω=1%) and two times 120 s per frame (three sets at different κ–angles) scans Secondary atom site location: difference Fourier map Hydrogen site location: inferred from neighbouring sites H-atom parameters constrained w = 1/[σ2(Fo 2) + (0.0276P)2] where P = (Fo 2 + 2Fc 2)/3 (Δ/σ)max = 0.001 Δρmax = 0.14 e Å−3 Δρmin = −0.10 e Å−3 Extinction correction: SHELXL97 (Sheldrick, 2008), Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance mat- rix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, convention- al R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R- factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) x y z Uiso*/Ueq O1 −0.2547 (2) 0.96841 (13) 0.63254 (16) 0.0723 (6) O2 0.1616 (3) 0.91394 (14) 0.55403 (19) 0.0818 (7) H2 0.2747 0.9160 0.5245 0.123* O3 −0.4523 (3) 0.95694 (15) 0.46477 (16) 0.0804 (6) C1 0.0831 (4) 0.99366 (19) 0.5670 (2) 0.0699 (9) H1 0.1979 1.0342 0.5700 0.084* C2 −0.0400 (4) 0.9980 (2) 0.6745 (2) 0.0717 (9) H2A −0.0512 1.0552 0.6971 0.086* C3 −0.2854 (5) 0.9770 (2) 0.5177 (3) 0.0677 (8) C4 −0.0916 (4) 1.0127 (2) 0.4718 (2) 0.0713 (9) H4 −0.1101 1.0720 0.4700 0.086* sup-3 supplementary materials supplementary materials sup-4 C5 −0.0562 (5) 0.9858 (2) 0.3503 (2) 0.0963 (11) H5A −0.0272 0.9284 0.3501 0.144* H5B 0.0629 1.0149 0.3246 0.144* H5C −0.1818 0.9971 0.2992 0.144* C6 0.0466 (4) 0.9499 (2) 0.7790 (2) 0.0766 (9) H6 0.0636 0.8934 0.7541 0.092* C7 0.2689 (5) 0.9825 (2) 0.8203 (3) 0.0999 (12) H7A 0.3668 0.9687 0.7647 0.150* H7B 0.3165 0.9585 0.8936 0.150* H7C 0.2628 1.0406 0.8283 0.150* C8 −0.1058 (5) 0.9493 (3) 0.8754 (3) 0.0969 (12) H8 −0.2441 0.9299 0.8397 0.116* C9 −0.1446 (7) 1.0344 (3) 0.9243 (3) 0.1352 (16) H9A −0.2459 1.0306 0.9809 0.203* H9B −0.1995 1.0698 0.8626 0.203* H9C −0.0125 1.0560 0.9598 0.203* C10 −0.0295 (7) 0.8869 (4) 0.9651 (4) 0.146 (2) H10 0.0090 0.8378 0.9327 0.175* C11 −0.0089 (10) 0.8863 (6) 1.0604 (6) 0.278 (5) H11A −0.0428 0.9323 1.1017 0.333* H11B 0.0422 0.8398 1.0995 0.333* O1' −0.6701 (3) 0.71545 (13) 0.46394 (18) 0.0769 (6) O2' −0.2446 (3) 0.67928 (15) 0.3828 (2) 0.0935 (7) H2' −0.1359 0.6868 0.3505 0.140* O3' −0.8637 (4) 0.71727 (16) 0.29367 (18) 0.0963 (8) C1' −0.3349 (5) 0.7549 (2) 0.4080 (3) 0.0777 (9) H1' −0.2255 0.7974 0.4203 0.093* C2' −0.4615 (4) 0.7458 (2) 0.5138 (3) 0.0727 (9) H2'1 −0.4816 0.8000 0.5465 0.087* C3' −0.7005 (5) 0.7353 (2) 0.3510 (3) 0.0794 (10) C4' −0.5091 (5) 0.7794 (2) 0.3145 (3) 0.0839 (10) H4' −0.5347 0.8379 0.3232 0.101* C5' −0.4680 (6) 0.7646 (3) 0.1898 (3) 0.1211 (15) H5'1 −0.3427 0.7940 0.1730 0.182* H5'2 −0.5883 0.7831 0.1396 0.182* H5'3 −0.4468 0.7074 0.1779 0.182* C6' −0.3719 (4) 0.6903 (2) 0.6094 (3) 0.0726 (9) H6' −0.3515 0.6367 0.5749 0.087* C7' −0.1534 (5) 0.7211 (2) 0.6567 (3) 0.0986 (12) H7'1 −0.0566 0.7169 0.5978 0.148* H7'2 −0.1013 0.6888 0.7224 0.148* H7'3 −0.1642 0.7770 0.6797 0.148* C8' −0.5233 (5) 0.6788 (2) 0.7046 (3) 0.0773 (9) H8' −0.6609 0.6623 0.6647 0.093* C9' −0.5664 (6) 0.7563 (3) 0.7697 (3) 0.1204 (14) H9'1 −0.4354 0.7760 0.8091 0.181* H9'2 −0.6664 0.7450 0.8252 0.181* H9'3 −0.6248 0.7968 0.7161 0.181* C10' −0.4516 (6) 0.6101 (3) 0.7795 (4) 0.1110 (13) sup-4 supplementary materials pp y sup H10' −0.4328 0.5614 0.7408 0.133* C11' −0.4126 (8) 0.6067 (4) 0.8851 (4) 0.183 (3) H11C −0.4276 0.6530 0.9300 0.220* H11D −0.3679 0.5579 0.9203 0.220* Atomic displacement parameters (Å2) U11 U22 U33 U12 U13 U23 O1 0.0470 (10) 0.0854 (17) 0.0864 (13) −0.0022 (11) 0.0168 (9) 0.0018 (13) O2 0.0649 (13) 0.0683 (17) 0.1164 (16) 0.0050 (11) 0.0310 (12) 0.0017 (13) O3 0.0569 (12) 0.0926 (18) 0.0930 (13) −0.0018 (13) 0.0134 (11) 0.0007 (13) C1 0.0543 (17) 0.052 (2) 0.106 (2) −0.0006 (16) 0.0204 (16) −0.0009 (18) C2 0.0513 (16) 0.072 (3) 0.094 (2) −0.0065 (16) 0.0167 (15) −0.0091 (19) C3 0.0549 (18) 0.063 (2) 0.088 (2) 0.0086 (17) 0.0190 (16) 0.0012 (19) C4 0.0609 (18) 0.065 (2) 0.090 (2) 0.0004 (16) 0.0210 (16) 0.0089 (17) C5 0.083 (2) 0.112 (3) 0.099 (2) −0.003 (2) 0.0322 (17) 0.004 (2) C6 0.0509 (16) 0.091 (3) 0.0888 (19) −0.0027 (17) 0.0115 (15) −0.007 (2) C7 0.0603 (18) 0.125 (4) 0.115 (2) −0.008 (2) 0.0097 (16) −0.012 (2) C8 0.0648 (19) 0.140 (4) 0.087 (2) −0.003 (2) 0.0156 (18) −0.007 (3) C9 0.111 (3) 0.173 (5) 0.128 (3) 0.024 (3) 0.047 (3) −0.021 (3) C10 0.106 (3) 0.249 (7) 0.086 (3) 0.007 (4) 0.027 (3) 0.030 (4) C11 0.147 (5) 0.476 (16) 0.222 (7) 0.051 (7) 0.075 (6) 0.165 (9) O1' 0.0496 (11) 0.0897 (18) 0.0938 (14) −0.0022 (11) 0.0186 (10) 0.0066 (12) O2' 0.0718 (14) 0.0719 (18) 0.1435 (19) 0.0044 (13) 0.0446 (13) 0.0045 (15) O3' 0.0646 (14) 0.125 (2) 0.1002 (15) −0.0110 (15) 0.0131 (12) 0.0065 (14) C1' 0.0634 (19) 0.056 (2) 0.117 (2) −0.0012 (17) 0.0241 (19) 0.003 (2) C2' 0.0534 (18) 0.060 (2) 0.106 (2) −0.0041 (16) 0.0122 (16) −0.003 (2) C3' 0.060 (2) 0.086 (3) 0.095 (2) 0.0041 (19) 0.0236 (18) 0.006 (2) C4' 0.073 (2) 0.069 (3) 0.112 (2) −0.0002 (18) 0.0255 (19) 0.011 (2) C5' 0.103 (3) 0.153 (4) 0.114 (3) −0.008 (3) 0.045 (2) 0.016 (3) C6' 0.0542 (17) 0.064 (2) 0.101 (2) 0.0017 (16) 0.0160 (16) −0.005 (2) C7' 0.0560 (18) 0.097 (3) 0.142 (3) −0.0047 (19) 0.0043 (18) −0.004 (2) C8' 0.0616 (18) 0.079 (3) 0.092 (2) 0.0030 (18) 0.0084 (16) 0.002 (2) C9' 0.107 (3) 0.128 (4) 0.128 (3) 0.021 (3) 0.019 (2) −0.026 (3) C10' 0.078 (2) 0.149 (4) 0.108 (3) 0.001 (3) 0.020 (2) 0.015 (3) C11' 0.134 (4) 0.252 (7) 0.161 (4) 0.028 (4) −0.001 (4) 0.069 (5) Geometric parameters (Å, °) O1—C3 1.336 (3) O1'—C3' 1.347 (3) O1—C2 1.474 (3) O1'—C2' 1.470 (3) O2—C1 1.411 (3) O2'—C1' 1.408 (4) O2—H2 0.8200 O2'—H2' 0.8200 O3—C3 1.211 (3) O3'—C3' 1.206 (3) C1—C4 1.515 (4) C1'—C4' 1.521 (4) C1—C2 1.532 (4) C1'—C2' 1.533 (4) C1—H1 0.9800 C1'—H1' 0.9800 C2—C6 1.504 (4) C2'—C6' 1.503 (4) C2—H2A 0.9800 C2'—H2'1 0.9800 Atomic displacement parameters (Å2) sup-5 supplementary materials supplementary materials 1.496 (4) C3'—C4' 1.515 (4) C4'—C5' 0.9800 C4'—H4' 0.9600 C5'—H5'1 0.9600 C5'—H5'2 0.9600 C5'—H5'3 1.531 (4) C6'—C7' 1.542 (4) C6'—C8' 0.9800 C6'—H6' 0.9600 C7'—H7'1 0.9600 C7'—H7'2 0.9600 C7'—H7'3 1.506 (7) C8'—C10' 1.536 (6) C8'—C9' 0.9800 C8'—H8' 0.9600 C9'—H9'1 0.9600 C9'—H9'2 0.9600 C9'—H9'3 1.102 (6) C10'—C11' 0.9300 C10'—H10' 0.9300 C11'—H11C 0.9300 C11'—H11D 109.6 (2) C3'—O1'—C2' 109.5 C1'—O2'—H2' 110.5 (3) O2'—C1'—C4' 109.8 (2) O2'—C1'—C2' 101.3 (2) C4'—C1'—C2' 111.6 O2'—C1'—H1' 111.6 C4'—C1'—H1' 111.6 C2'—C1'—H1' 110.1 (2) O1'—C2'—C6' 103.6 (2) O1'—C2'—C1' 117.4 (2) C6'—C2'—C1' 108.5 O1'—C2'—H2'1 108.5 C6'—C2'—H2'1 108.5 C1'—C2'—H2'1 120.9 (2) O3'—C3'—O1' 128.5 (3) O3'—C3'—C4' 110.6 (3) O1'—C3'—C4' 114.5 (3) C3'—C4'—C5' 102.7 (2) C3'—C4'—C1' 117.3 (2) C5'—C4'—C1' 107.3 C3'—C4'—H4' 107.3 C5'—C4'—H4' 107.3 C1'—C4'—H4' 109.5 C4'—C5'—H5'1 109.5 C4'—C5'—H5'2 109.5 H5'1—C5'—H5'2 109.5 C4'—C5'—H5'3 sup-6 C3—C4 1.496 (4) C3'—C4' C4—C5 1.515 (4) C4'—C5' C4—H4 0.9800 C4'—H4' C5—H5A 0.9600 C5'—H5'1 C5—H5B 0.9600 C5'—H5'2 C5—H5C 0.9600 C5'—H5'3 C6—C7 1.531 (4) C6'—C7' C6—C8 1.542 (4) C6'—C8' C6—H6 0.9800 C6'—H6' C7—H7A 0.9600 C7'—H7'1 C7—H7B 0.9600 C7'—H7'2 C7—H7C 0.9600 C7'—H7'3 C8—C10 1.506 (7) C8'—C10' C8—C9 1.536 (6) C8'—C9' C8—H8 0.9800 C8'—H8' C9—H9A 0.9600 C9'—H9'1 C9—H9B 0.9600 C9'—H9'2 C9—H9C 0.9600 C9'—H9'3 C10—C11 1.102 (6) C10'—C11' C10—H10 0.9300 C10'—H10' C11—H11A 0.9300 C11'—H11C C11—H11B 0.9300 C11'—H11D C3—O1—C2 109.6 (2) C3'—O1'—C2' C1—O2—H2 109.5 C1'—O2'—H2' O2—C1—C4 110.5 (3) O2'—C1'—C4' O2—C1—C2 109.8 (2) O2'—C1'—C2' C4—C1—C2 101.3 (2) C4'—C1'—C2' O2—C1—H1 111.6 O2'—C1'—H1' C4—C1—H1 111.6 C4'—C1'—H1' C2—C1—H1 111.6 C2'—C1'—H1' O1—C2—C6 110.1 (2) O1'—C2'—C6' O1—C2—C1 103.6 (2) O1'—C2'—C1' C6—C2—C1 117.4 (2) C6'—C2'—C1' O1—C2—H2A 108.5 O1'—C2'—H2'1 C6—C2—H2A 108.5 C6'—C2'—H2'1 C1—C2—H2A 108.5 C1'—C2'—H2'1 O3—C3—O1 120.9 (2) O3'—C3'—O1' O3—C3—C4 128.5 (3) O3'—C3'—C4' O1—C3—C4 110.6 (3) O1'—C3'—C4' C3—C4—C5 114.5 (3) C3'—C4'—C5' C3—C4—C1 102.7 (2) C3'—C4'—C1' C5—C4—C1 117.3 (2) C5'—C4'—C1' C3—C4—H4 107.3 C3'—C4'—H4' C5—C4—H4 107.3 C5'—C4'—H4' C1—C4—H4 107.3 C1'—C4'—H4' C4—C5—H5A 109.5 C4'—C5'—H5'1 C4—C5—H5B 109.5 C4'—C5'—H5'2 H5A—C5—H5B 109.5 H5'1—C5'—H5'2 C4—C5—H5C 109.5 C4'—C5'—H5'3 1.496 (4) C3'—C4' 1.500 (5) 1.515 (4) C4'—C5' 1.514 (4) 0.9800 C4'—H4' 0.9800 0.9600 C5'—H5'1 0.9600 0.9600 C5'—H5'2 0.9600 0.9600 C5'—H5'3 0.9600 1.531 (4) C6'—C7' 1.517 (4) 1.542 (4) C6'—C8' 1.538 (4) 0.9800 C6'—H6' 0.9800 0.9600 C7'—H7'1 0.9600 0.9600 C7'—H7'2 0.9600 0.9600 C7'—H7'3 0.9600 1.506 (7) C8'—C10' 1.469 (6) 1.536 (6) C8'—C9' 1.516 (5) 0.9800 C8'—H8' 0.9800 0.9600 C9'—H9'1 0.9600 0.9600 C9'—H9'2 0.9600 0.9600 C9'—H9'3 0.9600 1.102 (6) C10'—C11' 1.228 (5) 0.9300 C10'—H10' 0.9300 0.9300 C11'—H11C 0.9300 0.9300 C11'—H11D 0.9300 109.6 (2) C3'—O1'—C2' 109.9 (2) 109.5 C1'—O2'—H2' 109.5 110.5 (3) O2'—C1'—C4' 111.2 (3) 109.8 (2) O2'—C1'—C2' 109.3 (3) 101.3 (2) C4'—C1'—C2' 101.7 (2) 111.6 O2'—C1'—H1' 111.4 111.6 C4'—C1'—H1' 111.4 111.6 C2'—C1'—H1' 111.4 110.1 (2) O1'—C2'—C6' 110.1 (2) 103.6 (2) O1'—C2'—C1' 103.3 (2) 117.4 (2) C6'—C2'—C1' 117.6 (2) 108.5 O1'—C2'—H2'1 108.5 108.5 C6'—C2'—H2'1 108.5 108.5 C1'—C2'—H2'1 108.5 120.9 (2) O3'—C3'—O1' 120.8 (3) 128.5 (3) O3'—C3'—C4' 128.8 (3) 110.6 (3) O1'—C3'—C4' 110.4 (3) 114.5 (3) C3'—C4'—C5' 114.1 (3) 102.7 (2) C3'—C4'—C1' 102.4 (3) 117.3 (2) C5'—C4'—C1' 117.5 (3) 107.3 C3'—C4'—H4' 107.4 107.3 C5'—C4'—H4' 107.4 107.3 C1'—C4'—H4' 107.4 109.5 C4'—C5'—H5'1 109.5 109.5 C4'—C5'—H5'2 109.5 109.5 H5'1—C5'—H5'2 109.5 109.5 C4'—C5'—H5'3 109.5 sup-6 supplementary materials supplementary materials 109.5 H5'1—C5'—H5'3 109.5 H5'2—C5'—H5'3 108.6 (3) C2'—C6'—C7' 112.7 (3) C2'—C6'—C8' 112.9 (2) C7'—C6'—C8' 107.5 C2'—C6'—H6' 107.5 C7'—C6'—H6' 107.5 C8'—C6'—H6' 109.5 C6'—C7'—H7'1 109.5 C6'—C7'—H7'2 109.5 H7'1—C7'—H7'2 109.5 C6'—C7'—H7'3 109.5 H7'1—C7'—H7'3 109.5 H7'2—C7'—H7'3 114.5 (3) C10'—C8'—C9' 109.1 (3) C10'—C8'—C6' 113.1 (3) C9'—C8'—C6' 106.5 C10'—C8'—H8' 106.5 C9'—C8'—H8' 106.5 C6'—C8'—H8' 109.5 C8'—C9'—H9'1 109.5 C8'—C9'—H9'2 109.5 H9'1—C9'—H9'2 109.5 C8'—C9'—H9'3 109.5 H9'1—C9'—H9'3 109.5 H9'2—C9'—H9'3 134.4 (8) C11'—C10'—C8' 112.8 C11'—C10'—H10' 112.8 C8'—C10'—H10' 120.0 C10'—C11'—H11C 120.0 C10'—C11'—H11D 120.0 H11C—C11'—H11D −148.1 (3) C3'—O1'—C2'—C6' −21.8 (3) C3'—O1'—C2'—C1' −83.7 (3) O2'—C1'—C2'—O1' 33.2 (3) C4'—C1'—C2'—O1' 37.9 (3) O2'—C1'—C2'—C6' 154.7 (3) C4'—C1'—C2'—C6' −179.6 (3) C2'—O1'—C3'—O3' 0.5 (3) C2'—O1'—C3'—C4' −30.6 (5) O3'—C3'—C4'—C5' 149.3 (3) O1'—C3'—C4'—C5' −158.8 (3) O3'—C3'—C4'—C1' 21.1 (3) O1'—C3'—C4'—C1' 84.0 (3) O2'—C1'—C4'—C3' −32.4 (3) C2'—C1'—C4'—C3' −42.5 (4) O2'—C1'—C4'—C5' −158.9 (3) C2'—C1'—C4'—C5' −179.8 (2) O1'—C2'—C6'—C7' H5A—C5—H5C 109.5 H5'1—C5'—H5'3 H5B—C5—H5C 109.5 H5'2—C5'—H5'3 C2—C6—C7 108.6 (3) C2'—C6'—C7' C2—C6—C8 112.7 (3) C2'—C6'—C8' C7—C6—C8 112.9 (2) C7'—C6'—C8' C2—C6—H6 107.5 C2'—C6'—H6' C7—C6—H6 107.5 C7'—C6'—H6' C8—C6—H6 107.5 C8'—C6'—H6' C6—C7—H7A 109.5 C6'—C7'—H7'1 C6—C7—H7B 109.5 C6'—C7'—H7'2 H7A—C7—H7B 109.5 H7'1—C7'—H7'2 C6—C7—H7C 109.5 C6'—C7'—H7'3 H7A—C7—H7C 109.5 H7'1—C7'—H7'3 H7B—C7—H7C 109.5 H7'2—C7'—H7'3 C10—C8—C9 114.5 (3) C10'—C8'—C9' C10—C8—C6 109.1 (3) C10'—C8'—C6' C9—C8—C6 113.1 (3) C9'—C8'—C6' C10—C8—H8 106.5 C10'—C8'—H8' C9—C8—H8 106.5 C9'—C8'—H8' C6—C8—H8 106.5 C6'—C8'—H8' C8—C9—H9A 109.5 C8'—C9'—H9'1 C8—C9—H9B 109.5 C8'—C9'—H9'2 H9A—C9—H9B 109.5 H9'1—C9'—H9'2 C8—C9—H9C 109.5 C8'—C9'—H9'3 H9A—C9—H9C 109.5 H9'1—C9'—H9'3 H9B—C9—H9C 109.5 H9'2—C9'—H9'3 C11—C10—C8 134.4 (8) C11'—C10'—C8' C11—C10—H10 112.8 C11'—C10'—H10' C8—C10—H10 112.8 C8'—C10'—H10' C10—C11—H11A 120.0 C10'—C11'—H11C C10—C11—H11B 120.0 C10'—C11'—H11D H11A—C11—H11B 120.0 H11C—C11'—H11D C3—O1—C2—C6 −148.1 (3) C3'—O1'—C2'—C6' C3—O1—C2—C1 −21.8 (3) C3'—O1'—C2'—C1' O2—C1—C2—O1 −83.7 (3) O2'—C1'—C2'—O1' C4—C1—C2—O1 33.2 (3) C4'—C1'—C2'—O1' O2—C1—C2—C6 37.9 (3) O2'—C1'—C2'—C6' C4—C1—C2—C6 154.7 (3) C4'—C1'—C2'—C6' C2—O1—C3—O3 −179.6 (3) C2'—O1'—C3'—O3' C2—O1—C3—C4 0.5 (3) C2'—O1'—C3'—C4' O3—C3—C4—C5 −30.6 (5) O3'—C3'—C4'—C5' O1—C3—C4—C5 149.3 (3) O1'—C3'—C4'—C5' O3—C3—C4—C1 −158.8 (3) O3'—C3'—C4'—C1' O1—C3—C4—C1 21.1 (3) O1'—C3'—C4'—C1' O2—C1—C4—C3 84.0 (3) O2'—C1'—C4'—C3' C2—C1—C4—C3 −32.4 (3) C2'—C1'—C4'—C3' O2—C1—C4—C5 −42.5 (4) O2'—C1'—C4'—C5' C2—C1—C4—C5 −158.9 (3) C2'—C1'—C4'—C5' O1—C2—C6—C7 −179.8 (2) O1'—C2'—C6'—C7' sup-7 109.5 H5'1—C5'—H5'3 109.5 109.5 H5'2—C5'—H5'3 109.5 108.6 (3) C2'—C6'—C7' 109.2 (3) 112.7 (3) C2'—C6'—C8' 113.0 (2) 112.9 (2) C7'—C6'—C8' 112.5 (3) 107.5 C2'—C6'—H6' 107.3 107.5 C7'—C6'—H6' 107.3 107.5 C8'—C6'—H6' 107.3 109.5 C6'—C7'—H7'1 109.5 109.5 C6'—C7'—H7'2 109.5 109.5 H7'1—C7'—H7'2 109.5 109.5 C6'—C7'—H7'3 109.5 109.5 H7'1—C7'—H7'3 109.5 109.5 H7'2—C7'—H7'3 109.5 114.5 (3) C10'—C8'—C9' 114.0 (3) 109.1 (3) C10'—C8'—C6' 110.1 (3) 113.1 (3) C9'—C8'—C6' 114.1 (3) 106.5 C10'—C8'—H8' 106.0 106.5 C9'—C8'—H8' 106.0 106.5 C6'—C8'—H8' 106.0 109.5 C8'—C9'—H9'1 109.5 109.5 C8'—C9'—H9'2 109.5 109.5 H9'1—C9'—H9'2 109.5 109.5 C8'—C9'—H9'3 109.5 109.5 H9'1—C9'—H9'3 109.5 109.5 H9'2—C9'—H9'3 109.5 134.4 (8) C11'—C10'—C8' 130.3 (5) 112.8 C11'—C10'—H10' 114.9 112.8 C8'—C10'—H10' 114.9 120.0 C10'—C11'—H11C 120.0 120.0 C10'—C11'—H11D 120.0 120.0 H11C—C11'—H11D 120.0 −148.1 (3) C3'—O1'—C2'—C6' −149.0 (3) −21.8 (3) C3'—O1'—C2'—C1' −22.6 (3) −83.7 (3) O2'—C1'—C2'—O1' −84.1 (3) 33.2 (3) C4'—C1'—C2'—O1' 33.5 (3) 37.9 (3) O2'—C1'—C2'—C6' 37.4 (4) 154.7 (3) C4'—C1'—C2'—C6' 155.1 (3) −179.6 (3) C2'—O1'—C3'—O3' −178.9 (3) 0.5 (3) C2'—O1'—C3'—C4' 1.6 (3) −30.6 (5) O3'—C3'—C4'—C5' −31.2 (6) 149.3 (3) O1'—C3'—C4'—C5' 148.3 (3) −158.8 (3) O3'—C3'—C4'—C1' −159.3 (4) 21.1 (3) O1'—C3'—C4'—C1' 20.2 (4) 84.0 (3) O2'—C1'—C4'—C3' 84.1 (3) −32.4 (3) C2'—C1'—C4'—C3' −32.2 (3) −42.5 (4) O2'—C1'—C4'—C5' −41.7 (4) −158.9 (3) C2'—C1'—C4'—C5' −158.0 (3) −179.8 (2) O1'—C2'—C6'—C7' 178.0 (2) H5A—C5—H5C 109.5 H5'1—C5'—H5'3 109.5 H5B—C5—H5C 109.5 H5'2—C5'—H5'3 109.5 C2—C6—C7 108.6 (3) C2'—C6'—C7' 109.2 (3) C2—C6—C8 112.7 (3) C2'—C6'—C8' 113.0 (2) C7—C6—C8 112.9 (2) C7'—C6'—C8' 112.5 (3) C2—C6—H6 107.5 C2'—C6'—H6' 107.3 C7—C6—H6 107.5 C7'—C6'—H6' 107.3 C8—C6—H6 107.5 C8'—C6'—H6' 107.3 C6—C7—H7A 109.5 C6'—C7'—H7'1 109.5 C6—C7—H7B 109.5 C6'—C7'—H7'2 109.5 H7A—C7—H7B 109.5 H7'1—C7'—H7'2 109.5 C6—C7—H7C 109.5 C6'—C7'—H7'3 109.5 H7A—C7—H7C 109.5 H7'1—C7'—H7'3 109.5 H7B—C7—H7C 109.5 H7'2—C7'—H7'3 109.5 C10—C8—C9 114.5 (3) C10'—C8'—C9' 114.0 (3) C10—C8—C6 109.1 (3) C10'—C8'—C6' 110.1 (3) C9—C8—C6 113.1 (3) C9'—C8'—C6' 114.1 (3) C10—C8—H8 106.5 C10'—C8'—H8' 106.0 C9—C8—H8 106.5 C9'—C8'—H8' 106.0 C6—C8—H8 106.5 C6'—C8'—H8' 106.0 C8—C9—H9A 109.5 C8'—C9'—H9'1 109.5 C8—C9—H9B 109.5 C8'—C9'—H9'2 109.5 H9A—C9—H9B 109.5 H9'1—C9'—H9'2 109.5 C8—C9—H9C 109.5 C8'—C9'—H9'3 109.5 H9A—C9—H9C 109.5 H9'1—C9'—H9'3 109.5 H9B—C9—H9C 109.5 H9'2—C9'—H9'3 109.5 C11—C10—C8 134.4 (8) C11'—C10'—C8' 130.3 (5) C11—C10—H10 112.8 C11'—C10'—H10' 114.9 C8—C10—H10 112.8 C8'—C10'—H10' 114.9 C10—C11—H11A 120.0 C10'—C11'—H11C 120.0 C10—C11—H11B 120.0 C10'—C11'—H11D 120.0 H11A—C11—H11B 120.0 H11C—C11'—H11D 120.0 C3—O1—C2—C6 −148.1 (3) C3'—O1'—C2'—C6' −149.0 (3) C3—O1—C2—C1 −21.8 (3) C3'—O1'—C2'—C1' −22.6 (3) O2—C1—C2—O1 −83.7 (3) O2'—C1'—C2'—O1' −84.1 (3) C4—C1—C2—O1 33.2 (3) C4'—C1'—C2'—O1' 33.5 (3) O2—C1—C2—C6 37.9 (3) O2'—C1'—C2'—C6' 37.4 (4) C4—C1—C2—C6 154.7 (3) C4'—C1'—C2'—C6' 155.1 (3) C2—O1—C3—O3 −179.6 (3) C2'—O1'—C3'—O3' −178.9 (3) C2—O1—C3—C4 0.5 (3) C2'—O1'—C3'—C4' 1.6 (3) O3—C3—C4—C5 −30.6 (5) O3'—C3'—C4'—C5' −31.2 (6) O1—C3—C4—C5 149.3 (3) O1'—C3'—C4'—C5' 148.3 (3) O3—C3—C4—C1 −158.8 (3) O3'—C3'—C4'—C1' −159.3 (4) O1—C3—C4—C1 21.1 (3) O1'—C3'—C4'—C1' 20.2 (4) O2—C1—C4—C3 84.0 (3) O2'—C1'—C4'—C3' 84.1 (3) C2—C1—C4—C3 −32.4 (3) C2'—C1'—C4'—C3' −32.2 (3) O2—C1—C4—C5 −42.5 (4) O2'—C1'—C4'—C5' −41.7 (4) C2—C1—C4—C5 −158.9 (3) C2'—C1'—C4'—C5' −158.0 (3) O1—C2—C6—C7 −179.8 (2) O1'—C2'—C6'—C7' 178.0 (2) 109.5 H5'1—C5'—H5'3 109.5 H5'2—C5'—H5'3 108.6 (3) C2'—C6'—C7' 112.7 (3) C2'—C6'—C8' 112.9 (2) C7'—C6'—C8' 107.5 C2'—C6'—H6' 107.5 C7'—C6'—H6' 107.5 C8'—C6'—H6' 109.5 C6'—C7'—H7'1 109.5 C6'—C7'—H7'2 109.5 H7'1—C7'—H7'2 109.5 C6'—C7'—H7'3 109.5 H7'1—C7'—H7'3 109.5 H7'2—C7'—H7'3 114.5 (3) C10'—C8'—C9' 109.1 (3) C10'—C8'—C6' 113.1 (3) C9'—C8'—C6' 106.5 C10'—C8'—H8' 106.5 C9'—C8'—H8' 106.5 C6'—C8'—H8' 109.5 C8'—C9'—H9'1 109.5 C8'—C9'—H9'2 109.5 H9'1—C9'—H9'2 109.5 C8'—C9'—H9'3 109.5 H9'1—C9'—H9'3 109.5 H9'2—C9'—H9'3 134.4 (8) C11'—C10'—C8' 112.8 C11'—C10'—H10' 112.8 C8'—C10'—H10' 120.0 C10'—C11'—H11C 120.0 C10'—C11'—H11D 120.0 H11C—C11'—H11D −148.1 (3) C3'—O1'—C2'—C6' −21.8 (3) C3'—O1'—C2'—C1' −83.7 (3) O2'—C1'—C2'—O1' 33.2 (3) C4'—C1'—C2'—O1' 37.9 (3) O2'—C1'—C2'—C6' 154.7 (3) C4'—C1'—C2'—C6' −179.6 (3) C2'—O1'—C3'—O3' 0.5 (3) C2'—O1'—C3'—C4' −30.6 (5) O3'—C3'—C4'—C5' 149.3 (3) O1'—C3'—C4'—C5' −158.8 (3) O3'—C3'—C4'—C1' 21.1 (3) O1'—C3'—C4'—C1' 84.0 (3) O2'—C1'—C4'—C3' −32.4 (3) C2'—C1'—C4'—C3' −42.5 (4) O2'—C1'—C4'—C5' −158.9 (3) C2'—C1'—C4'—C5' −179.8 (2) O1'—C2'—C6'—C7' sup-7 supplementary materials supplementary materials C1—C2—C6—C7 62.1 (4) C1'—C2'—C6'—C7' 60.1 (4) O1—C2—C6—C8 −54.0 (4) O1'—C2'—C6'—C8' −56.0 (4) C1—C2—C6—C8 −172.1 (3) C1'—C2'—C6'—C8' −173.9 (3) C2—C6—C8—C10 168.6 (3) C2'—C6'—C8'—C10' 166.5 (3) C7—C6—C8—C10 −67.9 (5) C7'—C6'—C8'—C10' −69.3 (4) C2—C6—C8—C9 −62.7 (4) C2'—C6'—C8'—C9' −63.8 (4) C7—C6—C8—C9 60.8 (4) C7'—C6'—C8'—C9' 60.4 (4) C9—C8—C10—C11 7.2 (9) C9'—C8'—C10'—C11' −3.6 (7) C6—C8—C10—C11 135.1 (8) C6'—C8'—C10'—C11' 126.1 (5) Hydrogen-bond geometry (Å, °) D—H···A D—H H···A D···A D—H···A O2—H2···O3i 0.82 2.03 2.821 (3) 163 O2'—H2'···O3'i 0.82 1.96 2.771 (3) 171 Symmetry codes: (i) x+1, y, z. Hydrogen-bond geometry (Å, °) sup-8 supplementary materials Fig. 1 Fig. 1 sup-9 supplementary materials Fig. 2 Fig. 2 Fig. 2 sup-10
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https://pubs.aip.org/aip/cha/article-pdf/doi/10.1063/5.0147228/17961397/063120_1_5.0147228.pdf
en
Heteroclinic switching between chimeras in a ring of six oscillator populations
Chaos
2,023
cc-by
9,408
RESEARCH ARTICLE | JUNE 05 2023 Heteroclinic switching between chimeras in a ring of six oscillator populations Special Collection: Chimera states: from theory and experiments to technology and living systems Seungjae Lee ; Katharina Krischer  Chaos 33, 063120 (2023) https://doi.org/10.1063/5.0147228  View Online Export Citation 20 May 2024 10:05:47 Chaos ARTICLE scitation.org/journal/cha Heteroclinic switching between chimeras in a ring of six oscillator populations Cite as: Chaos 33, 063120 (2023); doi: 10.1063/5.0147228 Submitted: 20 February 2023 · Accepted: 15 May 2023 · Published Online: 5 June 2023 Seungjae Leea) View Online Export Citation CrossMark and Katharina Krischerb) AFFILIATIONS Physik-Department, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany Note: This paper is part of the Focus Issue on Chimera states from theory and experiments to technology and living systems. Electronic mail: seungjae.lee@tum.de b) Author to whom correspondence should be addressed: krischer@tum.de a) ABSTRACT © 2023 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). https://doi.org/10.1063/5.0147228 The synchronization of many coupled oscillators is a well-known phenomenon. An illustrative example is the synchronous flashing of fireflies in bushes in Southeast Asia.1 Let us now do a gedankenexperiment and consider six bushes full of fireflies arranged in a ring. Let us further assume that the fireflies within one bush exchange information on their respective “firing state” with a strong signal and to the fireflies on the neighboring bushes to the left and right with a weaker signal. We suggest in this paper that one possible outcome of such an interaction is that the fireflies in five of the six bushes still flash synchronously within each bush and with a phase difference of approximately 2π/6 to the other ones. In the sixth bush, however, the flashing occurs incoherently. Moreover, after some time, the incoherently flashing population becomes synchronized but a neighboring one loses synchrony and goes into incoherent flashing until a corresponding switching occurs between the next synchronously flashing population and the incoherent one. In this paper, we demonstrate with a simple generic model for six oscillator populations that such a cyclic Chaos 33, 063120 (2023); doi: 10.1063/5.0147228 © Author(s) 2023 switching between coherence and incoherence may, in fact, occur in systems of coupled oscillators. I. INTRODUCTION Collective dynamics of ensembles of coupled oscillators is of paramount importance in various interdisciplinary nonlinear sciences from physical systems to biological manifestations.1,2 Chimera states are symmetry-broken states emerging in a system of coupled oscillators in diverse fields of study. In the workshop, From theory and experiments to technology and living systems, an impressive collection of examples was presented.3 The archetypal chimera states were observed in a ring geometry with nonlocal interactions as a spatiotemporal dynamics.4–7 To simplify the nonlocal couplings on the ring while preserving its essential properties, many researchers have investigated systems of oscillator populations with all-to-all intra- and inter-population 33, 063120-1 20 May 2024 10:05:47 In a network of coupled oscillators, a symmetry-broken dynamical state characterized by the coexistence of coherent and incoherent parts can spontaneously form. It is known as a chimera state. We study chimera states in a network consisting of six populations of identical Kuramoto–Sakaguchi phase oscillators. The populations are arranged in a ring, and oscillators belonging to one population are uniformly coupled to all oscillators within the same population and to those in the two neighboring populations. This topology supports the existence of different configurations of coherent and incoherent populations along the ring, but all of them are linearly unstable in most of the parameter space. Yet, chimera dynamics is observed from random initial conditions in a wide parameter range, characterized by one incoherent and five synchronized populations. These observable states are connected to the formation of a heteroclinic cycle between symmetric variants of saddle chimeras, which gives rise to a switching dynamics. We analyze the dynamical and spectral properties of the chimeras in the thermodynamic limit using the Ott–Antonsen ansatz and in finite-sized systems employing Watanabe–Strogatz reduction. For a heterogeneous frequency distribution, a small heterogeneity renders a heteroclinic switching dynamics asymptotically attracting. However, for a large heterogeneity, the heteroclinic orbit does not survive; instead, it is replaced by a variety of attracting chimera states. Chaos II. GOVERNING EQUATIONS AND SADDLE CHIMERAS We study the dynamics of a network of six populations of Kuramoto–Sakaguchi phase oscillators: φj(a) (t) ∈ [−π , π ) =: T for j = 1, . . . , N (oscillator index) and a = 1, . . . , 6 (population index). Chaos 33, 063120 (2023); doi: 10.1063/5.0147228 © Author(s) 2023 scitation.org/journal/cha The 6N microscopic governing equations are given by   (a) d (a) −iφ φj = ωj(a) + Im Ha (t)e j e−iα dt = ωj(a) + 6 X N Kab b=1   1 X sin φk(b) − φj(a) − α , N (1) k=1 with j = 1, . . . , N and a = 1, . . . , 6. Ha (t) denotes an effective forcing function18 acting on the oscillators in population a defined by P Ha (t) := 6b=1 Kab 0b (t), where 0a (t) ∈ C is the complex Kuramoto order parameter of each population defined as N 0a (t) := 1 X iφj(a) (t) e N j=1 (2) for a = 1, . . . , 6. The coupling matrix (Kab ) is given by ( µ=1 for a = b, Kab = ν = 1 − A for a = b ± 1 mod 6, with a, b = 1, . . . , 6 (from here on, population indices are taken modulo 6). The coupling matrix defines a network topology that is schematically depicted in Fig. 1(a): each oscillator is coupled to all oscillators within the same population with coupling strength µ = 1 and connected to all oscillators in the two neighboring populations with ν = 1 − A, where A ∈ [0, 1]. The phase-lag parameter α is taken as α = π2 − β with a fixed value of β = 0.008 throughout the paper unless otherwise noted. First, we consider the thermodynamic limit in which, for each population, N → ∞. In this limit, the state function is a continuous distribution function fa (φ (a) , ω(a) , t) governed by the continuity equation,   ∂ ∂ (a) (a) (a) (a) (a) (a) fa (φ , ω , t) = − (a) fa (φ , ω , t)va (φ , ω , t) ∂t ∂φ (3)   va (φ (a) , ω(a) , t) := ω(a) + Im Ha (t)e−iφ (a) e−iα for a = 1, . . . , 6, and the Kuramoto order parameter of each population reads Z Z  (a) 0a (t) = fa φ (a) , ω(a) , t eiφ dφ (a) dω(a) . R T Exploiting the so-called Ott–Antonsen ansatz,38,39 the ensemble dynamics can be expressed through the dynamics of the order parameter. In the Ott–Antonsen invariant manifold, the Fourier series expansion of the oscillator phase density function can be written in terms of the first harmonic Za (ω(a) , t) ∈ C only, all the higher Fourier harmonics being a power of Za (ω(a) , t), ! ∞ h i X g(ω(a) ) n −inφ (a) (a) fa = (4) Za (ω , t) e + c.c . 1+ 2π n=1 Here, c.c. stands for the complex conjugate and g(ω) specifies the natural frequency distribution, which we assume to be a Cauchy–Lorentz distribution with half-width γ ∈ R and zero mean: 33, 063120-2 20 May 2024 10:05:47 coupling with different intra- and inter-population coupling strengths. Emphasis was initially on two-population networks8–13 and was later extended to three-population and multi-population networks.14–17 The chimera states in these networks exhibit a variety of dynamics distinguished by the temporal behavior of the degree of coherence of the incoherent populations. Examples range from stationary order parameter dynamics, over periodic breathing chimera states9,10 to quasiperiodic18,19 and chaotic chimera states.20–24 Also, more complex variants of chimera states, known as alternating or switching chimeras, have been reported. This state is characterized by continuously exchanging the coherent and the incoherent domains. Previous investigations have shown that switching chimeras occur in systems that exhibit either metastable states or heteroclinic cycles. In the former case, the switching is either triggered by large enough fluctuations,25–28 or by arbitrarily small noise with power-law scaling originating from intermingled basins of attraction,29 whereas in the latter case, the switching occurs between saddle states.30–36 In this paper, we investigate switching dynamics along a heteroclinic cycle between saddle chimeras in phase space. In previous works on this type of heteroclinic switching, populations of phase oscillators, governed by a non-pairwise sinusoidal coupling with a higher-order interaction were considered.30,31 Each oscillator was coupled to the oscillators in the same population and to those in the two nearest populations. The author demonstrated how the interplay between higher-order interactions and network topology enables switching dynamics between localized frequency synchronization patterns (so-called weak chimeras24,37) existing in populations with few oscillators. Our study here considers a similar network topology, i.e., a ring of oscillator populations with global intra-population coupling, whereby we focus on six populations. In contrast to the former works, we consider identical phase oscillators with harmonic or sinusoidal pairwise coupling, so-called Kuramoto–Sakaguchi oscillators. Furthermore, we study the dynamics both in the thermodynamic limit and in finite-sized ensembles with dimension reductions for each population, namely, the Ott–Antonsen (OA) ansatz38–40 and Watanabe–Strogatz (WS) transformation,18,19,41 respectively.42 In Sec. II, we introduce governing equations of the system in the thermodynamic limit using the Ott–Antonsen ansatz and show that the system possesses various saddle chimera states. In Sec. III, we study the dynamical and spectral properties of the saddle chimera states and demonstrate a heteroclinic switching between them, which is observed both in the thermodynamic limit and finitesized ensembles. In the deterministic system, the switching fades away after a long time transient. However, a small noise renders the switching persistent and the average switching period exhibits a power-law scaling. The impact of a heterogeneous natural frequency distribution on the system’s dynamics is considered in Sec. IV. Finally, we summarize the results in Sec. V. ARTICLE Chaos ARTICLE scitation.org/journal/cha FIG. 1. (a) Schematic of the considered network topology. The intra-population coupling is all-to-all with strength µ = 1 and the inter-population coupling is also all-to-all but only between the nearest-neighbor populations and with strength ν = 1 − A. (b) A normalized histogram of occurrence of chimera states from 300 random initial conditions at t = 5 × 104 . 1 1 d za (t) = −γ za + Ha (t)e−iα − z2a Ha (t)eiα . dt 2 2 (5) For simplification, we write Eq. (5) in polar coordinates 6 1 − ρa2 X dρa Kab ρb cos(ϕb − ϕa − α) = −γρa + dt 2 b=1  1 − ρa2 = −γρa + νρa+1 cos(ϕa+1 − ϕa − α) 2  + νρa−1 cos(ϕa−1 − ϕa − α) + µρa cos α (6) and 6 1 + ρa2 X dϕa Kab ρb sin(ϕb − ϕa − α) = dt 2ρa b=1  1 + ρa2 = νρa+1 sin(ϕa+1 − ϕa − α) 2ρa  + νρa−1 sin(ϕa−1 − ϕa − α) − µρa sin α , (7) where za (t) = ρa (t)eiϕa (t) for a = 1, . . . , 6. Up to Sec. IV, we only consider identical oscillators. Hence, first, we set γ = 0. Then, in terms of the OA variables, a synchronized (S) population is characterized by ρa = 1 and a common phase ϕa ∈ T while we denote a population as desynchronized (D) if 0 < ρa < 1. In the latter case, Chaos 33, 063120 (2023); doi: 10.1063/5.0147228 © Author(s) 2023 ϕa represents the mean phase.14 Solving Eqs. (6) and (7) and substituting the results into Eq. (4), the continuous distribution function is of the form (  δ ϕa − φ (a) for ρa = 1, (a) fa (φ , t) = (8) Pρa (ϕa − φ (a) ) for 0 < ρa < 1, where δ(θ ) is the Dirac delta distribution characterizing the syn2 is the normalized chronized population and Pr (θ ) = 2π1 1−2r1−r cos θ +r2 Poisson kernel corresponding to the desynchronized population.43 Possible solutions of Eqs. (6) and (7) are S6 = S · · · S (6 times) states in which ρa (t) = 1 and ϕa (t) = t + 2π6 q a with the common frequency  for a = 1, . . . , 6 and q ∈ {0,±1, ±2}. From Eqs. (6) and (7), we obtain  = −(µ + 2ν cos π3q ) sin α. Each population is internally synchronized while their mean phases follow a twisted state in a ring.44 Note that the case where all the populations have the same phase is q = 0. The linear stability analysis reveals that the S6 states with q = 0, ±1 are stable fixed points in a rotating reference frame, whereas those for q = ±2 are unstable. The real parts of the eigenvalues of the Jacobian matrix evaluated at S6 for q = 0, ±1 are all negative, except for one, which is zero and reflects the phase shift invariance. Furthermore, there are fixed points corresponding to chimera states. These fixed points are unstable in nearly the entire parameter regime. Their structure is dictated by the network 2 symmetry.45–47 Examples are (SD)3 = SDSDSD, (DS2 ) = DS2 DS2 5 or DS = DSSSSS and so on. Note that the equations of motion (6) and (7) are invariant under the group of transformation Z6 := Z/6Z such that cyclic permutations of the populations of the mentioned fixed points are fixed points as well with the same properties.30 In a large interval of A, the Jacobian matrix evaluated at each chimera state has at least one eigenvalue with positive real part. For instance, 2 for A = 0.3, (DS2 ) shows four real positive eigenvalues, (SD)3 has 33, 063120-3 20 May 2024 10:05:47 1 g(ω) = πγ ω2 +γ 2 . Using Eq. (4), continuity equation (3) yields the socalled Ott–Antonsen equation, an evolution equation for the order parameter za (t) := Za (iγ , t) = 0a (t) for a = 1, . . . , 6, Chaos ARTICLE scitation.org/journal/cha a pair of complex conjugate eigenvalues with positive real parts, and DS5 has one positive real eigenvalue. In summary, no stable chimera fixed point solution is found for A > 0.2; they all are saddle chimera solutions. To test for possible nontrivial long-term dynamics in the A − β parameter plane, we performed numerical integrations48 of Eqs. (6) and (7) from 300 random initial conditions at each set of parameters for A ∈ [0.2, 0.7] and β ∈ [0.002, 0.01]. In a considerable number of these simulations, the trajectory settles down to the DS5 chimera state or one of its cyclic permutations. The histogram depicted in Fig. 1(b) quantifies the probability with which a trajectory attains such a chimera dynamics in the long-term limit in the parameter plane. None other than a DS5 -type chimera was obtained. The latter observation is remarkable since in the considered parameter range all DS5 -type chimeras are unstable, and, starting from random initial conditions, one would not expect that trajectories approach a saddle fixed point. In Secs. III and IV, we will discuss the phase space structure that allows for this peculiar behavior in detail. III. HETEROCLINIC SWITCHING BETWEEN SADDLE CHIMERA STATES A. Stationary saddle chimeras q := M 1 X 1a+1,a ∈ Z, 2π a=1 (9) where 1a,b := ϕa − ϕb . In all cases, we obtain numerically q ∈ {+1, −1}. Let us first consider q = 1. The chimera state is found to be an unstable fixed point in a rotating reference frame, i.e., {DS5 } ⊂ [0, 1]6 × T6 is an invariant saddle point under the flow of Eqs. (6) and (7). Likewise, all the five cyclic permutations of it are unstable fixed points. In Fig. 2(a), eigenvalues of the Jacobian matrix evaluated at DS5 are depicted in the complex plane: there is one positive real eigenvalue λ1 > 0 as well as one zero eigenvalue reflecting the phase shift invariance. All the other eigenvalues have negative real parts. Hence, the DS5 state is indeed a saddle chimera state with a one-dimensional unstable manifold Wu (DS5 ). The eigenvector corresponding to λ1 has a form of v1 = (A+ , 0, 0, 0, 0, A− , δϕ)> ∈ R12 , where A+ , A− ∈ R and δϕ denotes a perturbation on phase variables which does not prominently affect the dynamics in this context. From now on, we consider only the perturbation directions of the Chaos 33, 063120 (2023); doi: 10.1063/5.0147228 © Author(s) 2023 radial variables: v1 = (A+ , 0, 0, 0, 0, A− )> . Here, A+ A− < 0, which means that a small perturbation along the unstable manifold of DS5 raises (A+ > 0) the radial variable of the incoherent population ρ1 < 1, while it lowers (A− < 0) the radial variable of the nearest synchronized population ρ6 = 1 as schematically depicted in Fig. 2(b). Corresponding unstable directions are found for all symmetric variants of the DS5 . For q = −1, the radial parts of the eigenvector corresponding to the positive real eigenvalue is of the form v1 = (A+ , A− , 0, 0, 0, 0)> , and, therefore, the unstable perturbation lowers the radial variable of the nearest sync population on the other side of D. In numerical simulations, starting from DS5 and imposing a small perturbation along v1 , the trajectory jumps to S5 D for q = 1 and to SDS4 for q = −1. This implies that the one-dimensional unstable manifold of DS5 is connected to the stable manifold of S5 D for q = 1, particularly, via the most contracting eigendirection: Wu (DS5 ) ∩ Ws (S5 D) 6= ∅. Furthermore, both manifolds intersect the invariant subspace Z1 S4 Z6 , where the populations two to five are synchronized and Z1,6 denotes the state of the first and the sixth populations, respectively. In this reduced subspace, DS5 is a saddle and S5 D a sink. Considering the Z6 symmetry of the full system, the heteroclinic connection between DS5 and S5 D implies30 that there is a heteroclinic cycle of six saddle chimera states that forms an invariant subspace of the phase space, ( [DS5 → S5 D → · · · → SDS4 → DS5 ] for q = 1, C(q) := [DS5 → SDS4 → · · · → S5 D → DS5 ] for q = −1, (10) 33, 063120-4 20 May 2024 10:05:47 As mentioned above, for A ∈ (0.071, 0.45) and starting from random initial conditions, the long-term dynamics observed in numerical integration of Eqs. (6) and (7) frequently approaches a DS5 chimera state or one of its Z6 -symmetric counterparts. In fact, in numerics, the six saddle chimeras are obtained equally often from random initial conditions. For the moment, we focus on DS5 at A = 0.3 for simplicity. This stationary chimera state is characterized by ρ1 (t) = ρ0 < 1, ρa (t) = 1 for a = 2, . . . , 6. The phase dynamics is locked at the common frequency  and follows nearly a twisted state. Yet, the distribution of the ϕa (t) exhibits small deviations from a “pure” twisted state, which arise from ρ1 6= ρa = 1 for a = 2, . . . , 6; cf. the S6 state above for which ρa = 1 for a = 1, . . . , 6. Thus, the state shows characteristics of a nontrivial twisted state.49 Nevertheless, we can define a winding number of the phase variables along the ring as FIG. 2. (a) Eigenvalues of the Jacobian matrix evaluated at DS5 in the complex plane for A = 0.3. (b) Schematic of the perturbation along the unstable eigenspace that raises the incoherent population up to sync and lowers the radial variable of one of the two neighboring synchronized populations. (c) Schematic of switching between saddle chimera states along the heteroclinic cycle C(±1) defined in Eq. (10). Chaos ARTICLE scitation.org/journal/cha population,29,30 6 dρa 1 − ρa2 X Kab ρb cos(ϕb − ϕa − α) − η|Wa (t)| = dt 2 (11) b=1 for a = 1, . . . , 6. Here, Wa (t) is Gaussian noise with unit standard deviation and 0 < η  1 is its strength. Note that by taking the absolute value of Wa (t) and subtracting the noise term, we ensure that ρa (t) < 1 also for the synchronized populations for all times. Figure 3(b) shows a persistent switching dynamics near the heteroclinic cycle of the saddle chimera states obtained for η = 10−15 . In Fig. 3(c), it can be seen that the average switching period hT̃i decreases with increasing noise strength η according to a power-law scaling. Hence, one may expect that the switching dynamics is persistent near C(q) even at much smaller noise intensity than we could achieve due to the resolution limit of the numerical simulations. In contrast, increasing η beyond the highest value depicted in Fig. 3(c) destroys the switching dynamics. FIG. 3. (a) Time evolution of the radial variables of the OA dynamics from a random initial condition. (b) Time evolution of the radial variables of the OA dynamics with an imposed noise: η = 10−15 . (c) Log–log plot of the average switching period vs the strength of the noise. The dashed line indicates hT̃i ∼ η−0.048 . Remaining parameters: A = 0.3 and β = 0.008. Chaos 33, 063120 (2023); doi: 10.1063/5.0147228 © Author(s) 2023 In Fig. 4(a), a bifurcation diagram of the stationary DS5 chimera state is depicted. It is born in a saddle-node bifurcation (LP) at ALP = 0.0678 (red, see upper inset). One of the two DS5 branches emerging from LP is, in fact, stable in a narrow A-interval. The other upper branch separates the basins of attraction of the stable DS5 chimera state and the stable S6 (q = 0) solution. This upper branch is not observable at all and is not considered further in this work. The stable DS5 chimera and its symmetric counterparts are destabilized in a transcritical bifurcation (BP) at ABP = 0.070 08 through an interaction with a DS4 D0 state (black), which possesses two incoherent populations that have different values of the radial variables, ρ1 6= ρ6 . This state exchanges at ABP its stability with DS5 . The unstable direction of the latter is of the form v = (A+ , 0, 0, 0, 0, A− )> as discussed above. Yet, close to the bifurcation point, a perturbation along this unstable eigendirection leads the trajectory not yet to the next symmetric variant along C(q) but to the DS4 D0 state. The heteroclininc cycle only emerges after a sequence of further bifurcations in which the DS4 D0 state interacts with several other solution branches, which are not further discussed here. At least from A = 0.15 on, we observe then the heteroclinic switching dynamics in numerical integrations as described above [cf. Fig. 3(a)]. This heteroclinic switching between the stationary saddle chimeras persists until they undergo a supercritical Hopf bifurcation (HB) at AHB = 0.451, giving rise to a limit-cycle solution characterized by ρ1 (t) = ρ1 (t + T) < 1 and ρa = 1 for a = 2, . . . , 6 (blue), where T denotes the period of it. Example trajectories at points (A) and (B) along the limit-cycle solution are shown in insets (A) and (B). The angular variables still behave like a nontrivial twisted state with the winding number q = ±1. This periodic breathing chimera solution is also unstable with one positive real Floquet multiplier larger than unity. Again, as for the stationary saddle SD5 state, in the long-term dynamics, we observe the unstable breathing chimera solutions from random initial conditions. In order to shed light on this observation, we calculate Lyapunov exponents (LEs)50,51 and covariant Lyapunov vectors (CLVs)52,53 along the observed breathing chimera trajectory. In Fig. 4(b), the Lyapunov exponents of the 33, 063120-5 20 May 2024 10:05:47 the winding number q taking over the role of a direction indicator of the heteroclinic switching. The heteroclinic cycles C(±1) are illustrated in Fig. 2(c). Note that for other chimera fixed points, such as 2 (SD)3 or (DS2 ) , neither switching nor any long-term dynamics is detected in numerical integration of Eqs. (6) and (7). In Fig. 3(a), a representative trajectory is depicted that shows the switching dynamics between the six saddle chimera states. The switching between synchronous and asynchronous dynamics occurs always between neighboring populations and has a unique sense of rotation. Hence, the trajectory follows the heteroclinic orbit. The average time intervals between the switching increases until eventually the trajectory remains in one of the saddle chimera states. Yet, the motion along the heteroclinic orbit constitutes a long-term switching. During this period, on average, the full symmetry of the system Eqs. (6) and (7) is recovered while a saddle chimera state has a broken symmetry.29 Furthermore, the formation of the heteroclinic cycle explains why saddle chimera states can be observed in a wide range of parameters, as quantified above with Fig. 1(b). When the switching happens, the radial dynamics of one synchronized population next to the incoherent population gets lowered along the unstable eigendirection of the saddle chimera state and shows an oscillatory damped motion before taking on an almost stationary value. The oscillatory transient is caused by complex conjugate eigenvalues with negative real parts and corresponding eigenvectors for a switching from DS5 to S5 D. Thus, upon switching, the trajectory spirals from one saddle chimera state to the next one along C(q) in Eq. (10). Next, for the switching dynamics between saddle chimera states to be persistent, we add a small noise to the radial dynamics of each B. Breathing saddle chimeras Chaos breathing chimera trajectory are shown. There is one positive LE, and two zero LEs corresponding to time and phase shift invariance. The positive LE 31 > 0 does not indicate a chaotic motion since the breathing chimera state exhibits periodic dynamics. Rather, it indicates a locally unstable direction of the reference trajectory in phase space. Furthermore, the CLV corresponding to 31 has a form v1 = (A+ , A− , 0, 0, 0, 0)> as the unstable eigenvector of the stationary saddle chimera. This suggests that all the symmetric variants of the unstable breathing chimera also form a heteroclinic cycle of type C(q). Indeed, we validate this conjecture with numerical integration from random initial conditions; a representative trajectory showing the switching dynamics near a heteroclinic cycle of the saddle limit-cycle chimeras along C(−1) is depicted in Fig. 4(c). It is Chaos 33, 063120 (2023); doi: 10.1063/5.0147228 © Author(s) 2023 scitation.org/journal/cha FIG. 5. Time evolutions of the radial variables of the WS dynamics in Eq. (16) from a random initial condition: (a) A = 0.3 (stationary chimeras). (b) A = 0.5 (breathing chimeras). (c) and (d) Lyapunov exponents corresponding to the stationary and breathing chimeras for A = 0.3 and A = 0.5, respectively. The same color scheme as in Fig. 4. All simulations were done with uniform constants of motion and N = 20. obtained for A = 0.5; compare the magnification of the limit-cycle in Fig. 4(c) and the inset (A) in Fig. 4(a). We confirmed that the switching dynamics near the heteroclinic cycle is persistent in the presence of noise [see Eq. (11), results not shown here]. C. Finite-sized ensembles We now turn our attention to finite-sized populations coupled in a ring topology as in Fig. 1(a). The macroscopic dynamics of each population can be formulated exploiting the Watanabe–Strogatz transformation,18,41 (a) (a) e iφj = ei8a ρa + e i(ψj −9a ) (a) 1 + ρa e i(ψj (12) −9a ) N for j = 1, . . . , N and a = 1, . . . , 6. Here, {ψj(a) }j=1 are N − 3 independent constants of motion for each population that satisfy three P P P constraints: Nj=1 cos ψj(a) = Nj=1 sin ψj(a) = 0 and Nj=1 ψj(a) = 0 41 for a = 1, . . . , 6. The distribution of the constants of motion takes an important role in the dynamics. First, we use uniform constants of motion given by ψj(a) = −π + 2π(j−1) for j = 1, . . . , N and a N 33, 063120-6 20 May 2024 10:05:47 FIG. 4. (a) Bifurcation diagram of the stationary chimera state DS5 . Upper inset: Magnification close to LP. Lower insets: The time evolutions of the radial variable of the incoherent population at points (A) and (B) of the bifurcation diagram corresponding to A = 0.5 and A = 0.6, respectively. Here, T is the period of the breathing chimera state. HB: Hopf bifurcation, LP: saddle-node bifurcation, and BP: transcritical bifurcation. Red (solid, dashed): (stable, unstable) unstable stationary chimera states, Blue dashed: unstable breathing chimera states. Note that the breathing chimera states undergo several saddle-node bifurcations. (b) Lyapunov exponents of the breathing chimera dynamics at A = 0.5. Red, blue, orange: positive, zero and negative LEs, respectively. (c) Switching dynamics of the radial variables of the OA dynamics as a function of time from a random initial condition at A = 0.5. Inset: Magnification of the times series around t = 6150. ARTICLE Chaos ARTICLE scitation.org/journal/cha   M d9a 1 − ρa2 X Kab ζb sin(ϕb − ϕa − α) + ξb cos(ϕb − ϕa − α) , = dt 2ρa b=1 ρa2 dϕa 1+ = dt 2ρa FIG. 6. Switching dynamics between quasiperiodic chimera states: Time evolution of the radial variables of the WS dynamics from a random initial condition with A = 0.5 and N = 20. The nonuniform constants of motion were obtained for p = 0.85. = 1, . . . , 6, such that the 3M governing equations of the WS variables read (13) for a = 1, . . . , 6. The WS variables are linked to the complex Kuramoto order parameter in Eq. (2) according to18,19 0a (t) = ρa (t)eiϕa (t) σa (ρa , 9a ; t) (14) for a = 1, . . . , 6. Here, σa is defined as 1 (ζa (t) + iξa (t)) ρa σa = N := (a) 1 X 2ρa + (1 + ρa2 ) cos(ψk − 9a ) ρa N 1 + 2ρa cos(ψk(a) − 9a ) + ρa2 k=1 N +i (a) 1 X (1 − ρa2 ) sin(ψk − 9a ) ρa N 1 + 2ρa cos(ψk(a) − 9a ) + ρa2 k=1 (15) for a = 1, . . . , 6. Using Eqs. (14) and (15), the 3M-dimensional WS dynamics is rewritten as10,54   M 1 − ρa2 X dρa Kab ζb cos(ϕb − ϕa − α) − ξb sin(ϕb − ϕa − α) , = dt 2 b=1 Chaos 33, 063120 (2023); doi: 10.1063/5.0147228 © Author(s) 2023 b=1   Kab ζb sin(ϕb − ϕa − α) + ξb cos(ϕb − ϕa − α) (16) for a = 1, . . . , 6. The Watanabe–Strogatz dynamics with the uniform constants of motion correspond to the finite-sized version of the Ott–Antonsen dynamics.19,40 In fact, we observe that the motion in both systems is qualitatively similar to each other from N = 10 on except for some finite-size effect due to σa (ρa , 9a ; t) in Eq. (15). Thus, the heteroclinic cycles of the stationary/breathing saddle chimeras exist also in the corresponding finite-sized systems. Exemplary results of the WS macroscopic dynamics with N = 20 are shown for stationary and breathing chimeras in Figs. 5(a) and 5(b), respectively. The time series of ρa (t) and the angular variables ϕa (t) for a = 1, . . . , 6 exhibit the same features as the corresponding Ott–Antonsen dynamics discussed in Sec. III. The stability analysis of the chimera trajectories in the finite-sized systems can be obtained from Lyapunov spectral analysis, which is shown in Figs. 5(c) and 5(d) for the states depicted in Figs. 5(a) and 5(b) after settling down to one of the saddle chimeras, respectively. Both chimera trajectories are characterized by one positive Lyapunov exponent, which again does not indicate a chaotic motion but rather a locally unstable direction along the reference trajectory. The CLV corresponding to the positive LE has the same form as the eigenvector corresponding to the positive eigenvalue in case of the OA dynamics, namely, v1 = (A+ , A− , 0, 0, 0, 0)> with A+ A− < 0. Note that one can distinguish the stationary and breathing chimera dynamics by counting the number of zero Lyapunov exponents. The breathing chimera state has one more zero LE than the stationary chimeras due to the additional Hopf frequency. In contrast to the OA dynamics, which is restricted to an invariant manifold, where the phases are distributed according to the normalized Poisson kernel, taking nonuniform constants of motion in the WS transformation, we can approach the dynamics outside the OA manifold. The nonuniform constants of motion are gen(a) erated from19 ψj(a) = (1 − p) π2 + π p(j−1) and ψj+N/2 = −(1 + p) π2 N/2 with p = 0.85. A dynamical state, which cannot be cap+ π p(j−1) N/2 tured by the OA dynamics, is the quasiperiodic chimera state reported in Ref. 18. In our network topology, we observe the switching dynamics between such quasiperiodic chimera states with nonuniform constants of motion. One realization for p = 0.85, A = 0.5, and N = 20 is shown in Fig. 6. This observation underlines that the heteroclinic cycle is a robust phenomenon dictated by the symmetry of the network topology. IV. NONIDENTICAL OSCILLATORS In Secs. IV A and IV B, we investigate nonidentical oscillators in a ring of the six oscillator populations. Here, we consider a heterogeneity characterized by γ in Eqs. (6) and (7) for the thermodynamic limit for which the OA manifold is known to be asymptotically attracting.11,39,55,56 Furthermore, the natural frequency of the 33, 063120-7 20 May 2024 10:05:47   d 1 − ρa2 ρa = Re Ha (t)e−iϕa e−iα , dt 2   d 1 − ρa2 9a = Im Ha (t)e−iϕa e−iα , dt 2ρa   1 + ρa2 d ϕa = Im Ha (t)e−iϕa e−iα dt 2ρa M X Chaos ARTICLE scitation.org/journal/cha oscillator is generated from the Cauchy–Lorentz distribution for finite-sized systems in Eq. (1). A. Small heterogeneity: γ = 10−6 First, we impose a small heterogeneity characterized by γ = 10−6 on the natural frequencies of the oscillators. This small heterogeneity renders the Ott–Antonsen dynamics, which is known to be neutrally stable for strictly identical oscillators, attracting.11,39,55,56 In Fig. 7(a), time series of the radial variables of the slightly heterogeneous systems are depicted for γ = 10−6 from a random initial condition. First of all, here we observe persistent switching of chimera states, which for identical oscillators was only detected in the presence of a low noise level. Yet, the switching phenomenology appears to be somewhat different. For most of the time, the chimera state is characterized by four S-populations and two D-populations.57 Consider, e.g., the evolution of the “brown” population in the time interval between T1 and T3 in Fig. 7(a). In the first half of this time interval, i.e., up to T2 , it switches roles with the “blue” neighboring population, which becomes an S-population while the brown one becomes a D-population. As soon as the “blue” population has reached the S-state, the switching process with the Chaos 33, 063120 (2023); doi: 10.1063/5.0147228 © Author(s) 2023 other “purple” neighbor sets in. Consequently, the trajectory corresponds to a strict DS5 chimera state or its symmetric counterparts only at periodic instants in time rather than during some time intervals. Furthermore, this persistent switching dynamics is attracting. This conjecture is confirmed by Lyapunov analysis. In Fig. 7(b), Lyapunov exponents that were obtained along a switching trajectory are shown. All the LEs are negative except for two zero arising from time and phase shift invariance. In order to study finite-sized ensembles, we need to directly investigate the microscopic dynamics in Eq. (1) (note that the Watanabe–Strogatz ansatz does not work for heterogeneous oscillator ensembles19). First, we obtain the natural frequencies from the Cauchy–Lorentz distribution according to j − 21 = N Z ωj g(ω)dω = −∞ 1 1 + tan−1 2 π  ω̃j γ  (17) oN n  . Direfor j = 1, . . . , N, which produces ωj = γ tan π(2j−1−N) 2N j=1 ctly solving the microscopic dynamics in Eq. (1) with γ = 10−6 , we observe a switching dynamics of the moduli of the Kuramoto order parameters defined in Eq. (2). In Fig. 7(c), time evolution of the 33, 063120-8 20 May 2024 10:05:47 FIG. 7. (a) Time evolution of the radial variables of the OA dynamics after discarding transient behavior from a random initial condition. (b) Lyapunov exponents of the switching dynamics calculated along the switching trajectory. (c) Time evolution of moduli of the Kuramoto order parameters obtained from the microscopic dynamics with a random initial condition and N = 20. The two arrows indicate the instants in time at which the snapshot in (d) were taken. (d) Phase snapshots of the microscopic dynamics for N = 20 at two points indicated in (c). Other parameters: γ = 10−6 and A = 0.3. Chaos ARTICLE scitation.org/journal/cha 20 May 2024 10:05:47 FIG. 8. (a) Time evolution of the radial variables for (DS)3 chimeras at A = 0.2. (b) Eigenvalues of the Jacobian matrix evaluated at (DS)3 in the complex plane at A = 0.2. (c) Bifurcation diagram of the (DS)3 chimera state. Solid and dashed lines indicate stable and unstable states, respectively. Black, red, blue, and green: uniform states, stationary, breathing, and period-doubled chimera solutions, respectively. moduli of the Kuramoto order parameters is depicted. The envelop of them follows the same switching dynamics as in Fig. 7(a), however with fluctuations superimposed, which stems from the finite-size effect. Two snapshots of the microscopic phases from a random initial condition are depicted in Fig. 7(d), which are indicated by the two arrows in Fig. 7(a). These are exactly the points in time at which there are five S- and one D-populations, corresponding to DS5 . As in the DS5 chimera state of the identical oscillator ensembles, the mean phases of the populations evolve as a nearly twisted state. Chaos 33, 063120 (2023); doi: 10.1063/5.0147228 © Author(s) 2023 B. Larger heterogeneity: γ = 10−4 1. Stationary chimera states Here, we consider a somewhat larger heterogeneity characterized by γ = 0.0001 in Eqs. (6) and (7). In this case, we do not observe any switching dynamics between chimera states from the numerical integration. We find an attracting stationary chimera state rather than the heteroclinic orbits between saddle chimeras. The attracting chimera state is of the type (DS)3 . No other type of chimeras is observed in our numerical integrations of Eqs. (6) and (7) from 33, 063120-9 Chaos ARTICLE scitation.org/journal/cha 20 May 2024 10:05:47 FIG. 9. Breathing [(a) and (b)], period-doubled [(c) and (d)], and quasiperiodic [(e) and (f)] chimera states for A = 0.274, A = 0.3, and A = 0.34, respectively. Left column: time series of the radial variables with insets magnifying the dynamics of the nearly synchronized populations. Right column: Lyapunov exponents with the same color scheme as in Fig. 4. random initial conditions. Looking at the network symmetry, the clusters C1 = {1, 3, 5} and C2 = {2, 4, 6} are, in fact, intertwined clusters,46,58 i.e., they form a so-called ISC set (independently synchronizable cluster set).45,59 This means that the stability of each cluster depends on the stability of the other cluster. In Fig. 8(a), time series of the radial variables of a stationary (DS)3 chimera starting from a random initial condition is shown for A = 0.2. It is characterized by ρa (t) = ρD < 1 (incoherent populations) for a = 1, 3, 5 and ρb (t) = ρS ≈ 1 (nearly synchronized populations) for b = 2, 4, 6. The phase variables are also locked at the common frequency. The phase differences between oscillators in the same cluster are found to be 2π3 , i.e., ϕa+2 − ϕa = 2π3 . In Chaos 33, 063120 (2023); doi: 10.1063/5.0147228 © Author(s) 2023 Fig. 8(b), the eigenvalues of the Jacobian matrix evaluated at (DS)3 are depicted in the complex plane. All the eigenvalues have negative real parts except for one zero corresponding to the phase shift invariance, confirming that the (DS)3 chimera is a linearly stable state. In Fig. 8(c), a bifurcation diagram of the (DS)3 chimera states is shown. For a small value of A, we find that a stable uniform solution (black) exists with ρa = ρ0 < 1 for a = 1, . . . , 6 and equally spaced phase variables. We can interpret this uniform state as consisting of two clusters C1 and C2 that are identical in their radial variables while the phase variables follow a twisted behavior. This uniform state is destabilized in a pitchfork bifurcation (PF) at APF 33, 063120-10 Chaos = 0.0323 in which one eigenvalue becomes positive. The eigenvector corresponding to the positive eigenvalue has the structure v = (δ+ , δ− , δ+ , δ− , δ+ , δ− )> , where δ+ δ− < 0. This means the uniform state is unstable along the transverse direction between two clusters. Due to the transversal instability, two symmetric solutions bifurcate from the uniform state in the pitchfork bifurcation, which is subcritical in our case (see Part A in Fig. 8). Each of the two solutions possesses a nearly synchronized cluster and an incoherent cluster which form together a chimera of the type (DS)3 or (SD)3 , respectively. Coming from low values of A, each of these two solution branches is born in a saddle-node bifurcation (LP) at ALP = 0.031 44 together with a stable, stationary (SD)3 —respectively, (DS)3 —chimera state. This chimera state is stable in a wide range of the parameter A as shown in Fig. 8(c). 2. Breathing, period-doubled and quasiperiodic chimera states FIG. 10. Time-parametric plot of ρ1 (t) vs ρ3 (t) for the time interval 1t = 3000 after discarding the transient behavior: breathing (blue), period-doubled (red), and quasiperiodic (black) chimera trajectories for A = 0.274, A = 0.3, and A = 0.34, respectively. Chaos 33, 063120 (2023); doi: 10.1063/5.0147228 © Author(s) 2023 scitation.org/journal/cha all Lyapunov exponents are negative, confirming that the breathing (DS)3 -type chimera is also attracting. This state exists only in a small interval of the parameter A. At APD = 0.279 95, it is destabilized in a supercritical period-doubling bifurcation (PD) [see Part B of Fig. 8(c)]. Panels (c) and (d) in Fig. 9 confirm the perioddoubled characteristics of the radial variables as well as the stability of the period-doubled chimera trajectory. Again, the radial variables exhibit the above specified spatiotemporal symmetry, with the difference that the period is nearly twice the period in Fig. 9(a). The period-doubled chimera state loses its stability in a supercritical torus bifurcation (TR) at ATR = 0.319 57. For A > ATR , one can observe a quasiperiodic chimera dynamics on a torus. An example dynamics and its stability are shown in Figs. 9(e) and 9(f). The quasiperiodic chimera is characterized by one more zero Lyapunov exponent arising from the second incommensurate frequency. The rich dynamics of the (DS)3 -type chimera states can be better appreciated in a time-parametric plot, where ρ1 (t) is plotted vs ρ3 (t) (Fig. 10). The breathing chimera state appears as a simple, closed loop (blue), whereas the period-doubled chimera state (red) follows a double-wound loop in the projected space. In contrast, the spatiotemporal symmetry of the quasiperiodic motion on the torus is broken (black). V. CONCLUSION AND OUTLOOK In this paper, we studied a system of six populations of identical Kuramoto–Sakaguchi phase oscillators in a ring topology. In the thermodynamic limit, the Ott–Antonsen dynamics possesses a variety of chimera solutions arising from the symmetry of the ring, most of them being unstable in nearly the entire parameter space. Only in a narrow interval of the inter-population coupling strength ν = 1 − A, we obtain stable chimera states characterized by one incoherent and five synchronized populations. These symmetric states are destabilized in a transcritical bifurcation and live in a large parameter region as saddle chimera states with one unstable direction. The six one-dimensional unstable manifolds of the saddle chimeras connect them in a heteroclinic cycle, rendering the chimera states observable in numerical integration from random initial conditions. Moreover, the trajectories display transient switching between the saddle chimera states, which becomes persistent when a small noise is imposed on the radial dynamics. At some large value of A, the stationary saddle chimeras undergo a Hopf bifurcation resulting in a heteroclinic orbit of saddle limitcycles. Thus, we also observe switching between breathing chimeras. Moreover, in finite-sized populations, we observed in addition a heteroclinic switching between quasiperiodic chimera states. A heteroclinic cycle even persists in the presence of small heterogeneity in the oscillator natural frequencies. This robust occurrence of heteroclinic cycles with three different variants of base states (stationary, breathing, and quasiperiodic) is in stark contrast to the dynamics of other network topologies. When using 3, 4, 5, 7, and 8 populations in a ring, we did not observe switching dynamics between chimera states from random initial conditions. Currently, we do not have a satisfactory explanation for why six populations behave differently. However, we note that in three-population networks, switching chimeras were obtained with different coupling functions, more precisely, pairwise intra-population coupling with higher harmonics 33, 063120-11 20 May 2024 10:05:47 The stationary (DS)3 -type chimera states are destabilized in a supercritical Hopf bifurcation (HB) at AHB = 0.268 12 giving rise to stable breathing chimera states. Trajectories of the radial variables are shown in Fig. 9(a) together with the Lyapunov spectrum in Fig. 9(b) for A = 0.274. The oscillations of the three populations within one cluster are time-shifted by T/3 and 2T/3, where T is the period of the radial variable, as can be clearly seen for the ) for a = incoherent population: ρa (t) = ρa+2 (t − T3 ) = ρa+4 (t − 2T 3 1, . . . , 6 (indices are taken modulo 6). In addition, except the two zero Lyapunov exponents connected to phase and time invariance, ARTICLE Chaos and sinusoidal nonpairwise inter-population coupling.30,31 It, thus, remains an interesting problem for future studies to investigate under which conditions observable heteroclinic cycles in oscillator networks exist. Finally, we considered oscillator ensembles with a wider distribution of the heterogeneous natural frequencies in the thermodynamic limit. Here, instead of saddle chimera states, attracting chimera states with various symmetries and complex order parameter dynamics dominate in phase space over a wide range of the parameter. The various macroscopic dynamics emerge in Hopf, period-doubling, and torus bifurcations. In conclusion, we have discovered several types of heteroclinic switching observable in the macroscopic dynamics of nearly identical oscillator populations arranged in a ring. One might be tempted to interpret this as a further step toward understanding the mechanism of the dynamics of neural oscillator networks,60,61 in particular, for encoding sequential information.30,62,63 However, as our study on a strong heterogeneity revealed, one has to be very careful before drawing this conclusion for a biological system. ACKNOWLEDGMENTS The authors would like to thank Young Sul Cho for providing additional computing facilities. This work has been supported by the Deutsche Forschungsgemeinschaft (Project No. KR1189/18-2). AUTHOR DECLARATIONS The authors have no conflicts to disclose. Author Contributions Seungjae Lee: Conceptualization (equal); Formal analysis (lead); Software (lead); Writing – original draft (lead); Writing – review & editing (supporting). Katharina Krischer: Funding acquisition (lead); Supervision (lead); Writing – review & editing (lead). DATA AVAILABILITY The data that support the findings of this study are available from the corresponding author upon reasonable request. REFERENCES 1 S. H. Strogatz, Sync (Hyperion, New York, 2003). A. Pikovsky, M. Rosenblum, and J. Kurths, Synchronization: A Universal Concept in Nonlinear Sciences (Cambridge University Press, Cambridge, 2001). 3 Chimera States: From Theory and Experiments to Technology and Living Systems (MPIPKS, Dresden, Germany, 2022), see https://www.pks.mpg.de/de/chimer22. 4 Y. Kuramoto and D. Battogtokh, “Coexistence of coherence and incoherence in nonlocally coupled phase oscillators,” Nonlinear Phenom. Complex Syst. 5, 380 (2002). 5 D. M. Abrams and S. H. Strogatz, “Chimera states for coupled oscillators,” Phys. Rev. Lett. 93, 174102 (2004). 6 M. J. Panaggio and D. M. Abrams, “Chimera states: Coexistence of coherence and incoherence in networks of coupled oscillators,” Nonlinearity 28, R67–R87 (2015). 7 O. E. Omel’chenko, “The mathematics behind chimera states,” Nonlinearity 31, R121–R164 (2018). 2 Chaos 33, 063120 (2023); doi: 10.1063/5.0147228 © Author(s) 2023 scitation.org/journal/cha 8 E. Montbrió, J. Kurths, and B. Blasius, “Synchronization of two interacting populations of oscillators,” Phys. Rev. E 70, 056125 (2004). 9 D. M. Abrams, R. Mirollo, S. H. Strogatz, and D. A. Wiley, “Solvable model for chimera states of coupled oscillators,” Phys. Rev. Lett. 101, 084103 (2008). 10 M. J. Panaggio, D. M. Abrams, P. Ashwin, and C. R. Laing, “Chimera states in networks of phase oscillators: The case of two small populations,” Phys. Rev. E 93, 012218 (2016). 11 S. Lee and K. Krischer, “Attracting Poisson chimeras in two-population networks,” Chaos 31, 113101 (2021). 12 O. Burylko, E. A. Martens, and C. Bick, “Symmetry breaking yields chimeras in two small populations of Kuramoto-type oscillators,” Chaos 32, 093109 (2022). 13 C. R. Laing, “Dynamics and stability of chimera states in two coupled populations of oscillators,” Phys. Rev. E 100, 042211 (2019). 14 E. A. Martens, “Bistable chimera attractors on a triangular network of oscillator populations,” Phys. Rev. E 82, 016216 (2010). 15 E. A. Martens, “Chimeras in a network of three oscillator populations with varying network topology,” Chaos 20, 043122 (2010). 16 C. R. Laing, “Chimeras on a ring of oscillator populations,” Chaos 33, 013121 (2023). 17 H. Hong, J. Jo, and S.-J. Sin, “Stable and flexible system for glucose homeostasis,” Phys. Rev. E 88, 032711 (2013). 18 A. Pikovsky and M. Rosenblum, “Partially integrable dynamics of hierarchical populations of coupled oscillators,” Phys. Rev. Lett. 101, 264103 (2008). 19 A. Pikovsky and M. Rosenblum, “Dynamics of heterogeneous oscillator ensembles in terms of collective variables,” Physica D 240, 872–881 (2011). 20 E. A. Martens, C. Bick, and M. J. Panaggio, “Chimera states in two populations with heterogeneous phase-lag,” Chaos 26, 094819 (2016). 21 D. Pazó and E. Montbrió, “Low-dimensional dynamics of populations of pulsecoupled oscillators,” Phys. Rev. X 4, 011009 (2014). 22 S. Olmi, “Chimera states in coupled Kuramoto oscillators with inertia,” Chaos 25, 123125 (2015). 23 S. Olmi, E. A. Martens, S. Thutupalli, and A. Torcini, “Intermittent chaotic chimeras for coupled rotators,” Phys. Rev. E 92, 030901 (2015). 24 C. Bick and P. Ashwin, “Chaotic weak chimeras and their persistence in coupled populations of phase oscillators,” Nonlinearity 29, 1468 (2016). 25 N. Semenova, A. Zakharova, V. Anishchenko, and E. Schöll, “Coherenceresonance chimeras in a network of excitable elements,” Phys. Rev. Lett. 117, 014102 (2016). 26 A. Buscarino, M. Frasca, L. V. Gambuzza, and P. Hövel, “Chimera states in timevarying complex networks,” Phys. Rev. E 91, 022817 (2015). 27 C. R. Laing, “Disorder-induced dynamics in a pair of coupled heterogeneous phase oscillator networks,” Chaos 22, 043104 (2012). 28 R. Ma, J. Wang, and Z. Liu, “Robust features of chimera states and the implementation of alternating chimera states,” Europhys. Lett. 91, 40006 (2010). 29 Y. Zhang, Z. G. Nicolaou, J. D. Hart, R. Roy, and A. E. Motter, “Critical switching in globally attractive chimeras,” Phys. Rev. X 10, 011044 (2020). 30 C. Bick, “Heteroclinic switching between chimeras,” Phys. Rev. E 97, 050201 (2018). 31 C. Bick, “Heteroclinic dynamics of localized frequency synchrony: Heteroclinic cycles for small populations,” J. Nonlinear Sci. 29, 2547–2570 (2019). 32 C. Bick and A. Lohse, “Heteroclinic dynamics of localized frequency synchrony: Stability of heteroclinic cycles and networks,” J. Nonlinear Sci. 29, 2571–2600 (2019). 33 S. W. Haugland, L. Schmidt, and K. Krischer, “Self-organized alternating chimera states in oscillatory media,” Sci. Rep. 5, 9883 (2015). 34 R. J. Goldschmidt, A. Pikovsky, and A. Politi, “Blinking chimeras in globally coupled rotators,” Chaos 29, 071101 (2019). 35 P. Ebrahimzadeh, M. Schiek, P. Jaros, T. Kapitaniak, S. van Waasen, and Y. Maistrenko, “Minimal chimera states in phase-lag coupled mechanical oscillators,” Eur. Phys. J. Spec. Top. 229, 2205–2214 (2020). 36 S. Brezetsky, P. Jaros, R. Levchenko, T. Kapitaniak, and Y. Maistrenko, “Chimera complexity,” Phys. Rev. E 103, L050204 (2021). 37 P. Ashwin and O. Burylko, “Weak chimeras in minimal networks of coupled phase oscillators,” Chaos 25, 013106 (2015). 38 E. Ott and T. M. Antonsen, “Low dimensional behavior of large systems of globally coupled oscillators,” Chaos 18, 037113 (2008). 33, 063120-12 20 May 2024 10:05:47 Conflict of Interest ARTICLE Chaos 39 E. Ott and T. M. Antonsen, “Long time evolution of phase oscillator systems,” Chaos 19, 023117 (2009). 40 S. A. Marvel, R. E. Mirollo, and S. H. Strogatz, “Identical phase oscillators with global sinusoidal coupling evolve by Möbius group action,” Chaos 19, 043104 (2009). 41 S. Watanabe and S. H. Strogatz, “Constants of motion for superconducting Josephson arrays,” Physica D 74, 197–253 (1994). 42 C. Bick, M. Goodfellow, C. R. Laing, and E. A. Martens, “Understanding the dynamics of biological and neural oscillator networks through exact mean-field reductions: A review,” J. Math. Neurosci. 10, 9 (2020). 43 C. R. Laing, “The dynamics of chimera states in heterogeneous Kuramoto networks,” Physica D 238, 1569–1588 (2009). 44 S. Lee, Y. S. Cho, and H. Hong, “Twisted states in low-dimensional hypercubic lattices,” Phys. Rev. E 98, 062221 (2018). 45 Y. S. Cho, T. Nishikawa, and A. E. Motter, “Stable chimeras and independently synchronizable clusters,” Phys. Rev. Lett. 119, 084101 (2017). 46 L. M. Pecora, F. Sorrentino, A. M. Hagerstrom, T. E. Murphy, and R. Roy, “Cluster synchronization and isolated desynchronization in complex networks with symmetries,” Nat. Commun. 5, 4079 (2014). 47 F. Sorrentino, L. Pecora, A. M. Hagerstrom, T. E. Murphy, and R. Roy, “Complete characterization of the stability of cluster synchronization in complex dynamical networks,” Sci. Adv. 2, e1501737 (2016). 48 W. R. Inc., “Mathematica, Version 12.0,” Champaign, IL, 2022: Numerical integration was performed in NDSolve with IDA. 49 S. Lee and K. Krischer, “Nontrivial twisted states in nonlocally coupled StuartLandau oscillators,” Phys. Rev. E 106, 044210 (2022). 50 A. Pikovsky and A. Politi, Lyapunov Exponents: A Tool to Explore Complex Dynamics (Cambridge University Press, Cambridge, 2016). ARTICLE scitation.org/journal/cha 51 V. Oseledets, “A multiplicative ergodic theorem. Characteristic Liapunov, exponents of dynamical systems,” Trans. Mosc. Math. Soc. 19, 197 (1968). 52 F. Ginelli, H. Chaté, R. Livi, and A. Politi, “Covariant Lyapunov vectors,” J. Phys. A: Math. Theor. 46, 254005 (2013). 53 P. V. Kuptsov and U. Parlitz, “Theory and computation of covariant Lyapunov vectors,” J. Nonlinear Sci. 22, 727 (2012). 54 S. Lee and K. Krischer, “Chaotic chimera attractors in a triangular network of identical oscillators,” Phys. Rev. E 107, 054205 (2023). 55 B. Pietras and A. Daffertshofer, “Ott-Antonsen attractiveness for parameterdependent oscillatory systems,” Chaos 26, 103101 (2016). 56 C. R. Laing, “Chimera states in heterogeneous networks,” Chaos 19, 013113 (2009). 57 Note that the small heterogeneity prevents the full synchronization of a population. Yet, we keep the same notation and refer to nearly synchronized populations with ρa ∈ [0.995, 1) as S-populations. 58 Y. S. Cho, “Concurrent formation of nearly synchronous clusters in each intertwined cluster set with parameter mismatches,” Phys. Rev. E 99, 052215 (2019). 59 To find cluster patterns, see https://github.com/tnishi0/grouping-clusters/. 60 P. Ashwin, S. Coombes, and R. Nicks, “Mathematical frameworks for oscillatory network dynamics in neuroscience,” J. Math. Neurosci. 6, 2 (2016). 61 E. Tognoli and J. S. Kelso, “The metastable brain,” Neuron 81, 35–48 (2014). 62 M. A. Komarov, G. V. Osipov, and J. A. K. Suykens, “Sequentially activated groups in neural networks,” Europhys. Lett. 86, 60006 (2009). 63 P. S. Skardal and A. Arenas, “Memory selection and information switching in oscillator networks with higher-order interactions,” J. Phys.: Complex. 2, 015003 (2021). 20 May 2024 10:05:47 Chaos 33, 063120 (2023); doi: 10.1063/5.0147228 © Author(s) 2023 33, 063120-13
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Measurement and Analysis of Urban Total Factor Energy Efficiency in China
E3S web of conferences
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Measurement and Analysis of Urban Total Factor Energy Efficiency in China Feifei Lu1, *, Yinling Lu2, and Na Lei3 1Management Science and Engineering, Lanzhou University of Technology, 730000Lanzhou, China 2Civil engineering, Xuchang City Planning and Design Institute, 461000Xuchang, China 3Civil engineering, Lanzhou University of Technology, 730000Lanzhou, China Abstract. The improvement of urban energy efficiency is of great significance to reduce carbon emissions and achieve China's goal of carbon peak in 2030. Taking 266 cities as the research objects, the energy efficiency of each city is measured by Super-SBM model. Then the energy efficiency is decomposed by Malmquist index. The results show that: In 2006, the number of cities in high-efficiency areas is small and high efficiency areas are mostly distributed in the northeast and southeast coastal areas. There was a phenomenon of low efficiency areas agglomeration. But in 2017, the number of high-efficiency cities increased significantly. The number of high-efficiency cities in Northeast China increased, the number of high-efficiency cities in Southeast coastal areas decreased, and the number of high-efficiency cities in Central China increased and showed a phenomenon of agglomeration of high-efficiency areas or relatively high efficiency areas. According to the decomposition of urban energy efficiency, technological progress is the main driving force for the improvement of energy efficiency, and the decline of technical efficiency inhibits the improvement of energy efficiency in various cities. energy efficiency is to create as high effective output as possible with as little resource input as possible, while restraining undesired output [2-5]. Most literatures believe that there is significant spatial difference in energy efficiency in different regions. *Corresponding author: lufeifei2505@163.com © The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/). 1 Introduction The Third China Energy Industry Development Annual Conference released the Review Framework of China's Urban Energy Reform, which believes that cities are the main body of the world's energy consumption and the main body of the implementation of various national energy policies. Analysis at the provincial level in China is difficult to solve the problem of total energy consumption distribution, so it is necessary to refine the study at the city level [1]. Cities gather all kinds of economic, technical and human support needed by energy transformation, so the study of urban energy efficiency has an important impact on exploring the characteristics of regional economic development. Urban economic development cannot be separated from energy, but economic development and energy development have brought serious problems of environmental degradation and energy depletion. In order to reduce the impact of economic development on the environment, the government has strengthened environmental regulation, but a debate has emerged between "green paradox" and "forcing emission reduction". In the face of multiple pressures, the breakthrough to improve urban energy efficiency is to actively explore the path of high-quality urban development, predict the comprehensive competitiveness of the city, and promote the sustainable development of the city. Based on the above analysis, although many scholars have studied energy efficiency, there are few analyses on the spatio-temporal differences of energy efficiency at the national level. Therefore, 266 cities in China are selected as the research objects, and the Super-SBM model is used to measure the energy efficiency of each city. According to Jenks natural breakpoint classification method, different energy efficiency zones are divided, and energy efficiency is further decomposed by Malmquist index. https://doi.org/10.1051/e3sconf/202126101020 https://doi.org/10.1051/e3sconf/202126101020 E3S Web of Conferences 261, 01020 (2021) ICEMEE 2021 @ EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 icenses/by/4.0/). 2.2 Establishment and explanation of China's urban energy efficiency measurement index system p p 1 1 1 1 1 1 1 0 1 ( , ) ( , ) ( , , , ) ( , ) ( , ) t t t t t t t t t t t t t t t t E x y E x y M x y x y E x y E x y          (2) The Malmquist index is further decomposed as follows: 0 sech M pech tech ch    (3) 1 1 1 1 1 1 1 0 1 ( , ) ( , ) ( , , , ) ( , ) ( , ) t t t t t t t t t t t t t t t t E x y E x y M x y x y E x y E x y          (2) (2) The Malmquist index is further decomposed as follows: 0 sech M pech tech ch    (3) According to "China City Statistical Yearbook", the prefecture-level cities and above were selected as the research objects, and the discontinuous data samples were eliminated. After adjusting the caliber of the unified administrative region, 266 cities and above were finally selected as the research samples. The research period was 12 years of panel data from 2006 to 2017. The selected index data and sources of China's urban energy efficiency measurement and spatial econometric model are shown in Table 1. (3) Where, pech represents the change of pure technical efficiency, reflecting the problem of technological dynamism; sech represents the change of scale efficiency, reflecting the impact of scale change on productivity by comparing the scale efficiency of different periods on the same production front; tech ch represents the change of technological progress, mainly describing the impact of technological progress on total factor productivity. The number of urban employees at the end of the year was used as the index of labor input. Capital stock as the substitution variable of capital input. 2.3 Decomposition model of urban energy efficiency in China (1) The urban energy efficiency is decomposed by the Malmquist index. The Malmquist index can be summarized into two aspects: one is the change of the technical efficiency of the evaluated unit in a period of time, the other is the change of the production technology of the evaluated unit itself. According to the decomposition method, the Malmquist index from period to period is decomposed as follows: In the formula,  is the effect value, m and s are input and output, iS  and iS  are relaxation variables of input and output respectively,  and are weights. 2.2 Establishment and explanation of China's urban energy efficiency measurement index system The perpetual inventory method is used to measure the capital stock, and the adjustment is carried out based on 2005.Energy consumption data is easy to cause errors due to different statistical calibers, and energy consumption is mostly output in the form of electricity, so the whole society's electricity consumption is selected as the measurement index of energy input. 2.1 Measurement model of urban energy efficiency in China Data Envelopment Analysis (DEA) model is used to construct a non-parametric "effective frontier" by using linear programming model, which is used to analysis the allocation of non-parametric technical efficiency of multiple inputs and outputs. DEA model does not need to set the weight, which can avoid the influence of subjective factors when establishing the production function. Super- SBM model uses the non-radial efficiency measurement method to avoid the problem of slack between input and At present, research on urban energy efficiency has made some progress. The core idea of optimizing urban E3S Web of Conferences 261, 01020 (2021) ICEMEE 2021 E3S Web of Conferences 261, 01020 (2021) https://doi.org/10.1051/e3sconf/202126101020 Expected output index Economic output GDP by City (adjusted for 2005) Undesired output indicators Pollutant output Industrial effluent discharge Industrial sulphur dioxide emissions Industrial soot emissions output. At the same time, linear combination is used to replace the decision-making unit of efficiency evaluation. When the efficiency value of decision-making unit reaches 1, further efficiency evaluation can still be carried out to realize the ranking of decision-making units. The formula of Super-SBM model is: 1 0 1 0 0 1, 0 0 1, 0 1 1 1 min 1 1 ( 1,2,..., ) . . ( 1,2,..., ) 1; 0; , , 0 m i i i s r r r n ij j jn ij j j n j j j S m X S s Y X X S j m s t Y Y S r s S S                                          (1) 3.1 Analysis of China's urban energy efficiency measurement results It shows that from 2006 to 2017, with the strengthening of environmental regulation, all cities in China can improve energy efficiency by Table 2. Energy efficiency decomp As can be seen from Figure 1, in 2006, most of the high-efficiency areas were distributed in the northeast and southeast coastal areas. In the central region, except for some cities in the high-efficiency area and the high- efficiency area, most of the provinces were in the low- efficiency area and the low-efficiency area. From the overall space, there was a phenomenon of agglomeration of low-efficiency areas. The number of cities with high efficiency in 2017 was significantly more than that in 2006. The number of cities with high efficiency in northeast China increased, but the number of cities with high efficiency in southeast coastal China decreased, and the number of cities with high efficiency in central China increased, showing the agglomeration of high efficiency areas or high efficiency areas. It shows that from 2006 to 2017, with the strengthening of environmental regulation, all cities in China can improve energy efficiency by accelerating green techno environmental governance technology. However, in the promoting the rapid econom of energy use brought by a transfer and the problem treatment may reduce the ene this area. 3.2 Decomposition of urb China In order to further study the changes, urban energy effici 2006 to 2017 through Malmq shown in Table 2. Table 2. Energy efficiency decomposition results of 266 cities in China accelerating green technology innovation, reducing environmental governance cost or improving energy technology. However, in the southeast coastal area, while promoting the rapid economic development, the pressure of energy use brought by a large number of population transfer and the problem of environmental pollution treatment may reduce the energy efficiency of the cities in this area. 3.2 Decomposition of urban energy efficiency in China In order to further study the causes of energy efficiency changes, urban energy efficiency was decomposed from 2006 to 2017 through Malmquist index, and the results are shown in Table 2. p gy y y Table 2. Energy efficiency decomposition results of 266 cities in China. Year Change of technical efficiency Change of technological progress Changes in pure technical efficiency Scale efficiency variation Energy efficiency variation 2006-2007 1.035 1.03 1.028 1.006 1.066 2007-2008 0.972 1.099 0.969 1.003 1.067 2008-2009 1.029 1.028 1.047 0.983 1.058 2009-2010 0.963 1.072 0.976 0.987 1.032 2010-2011 1.101 0.808 1.080 1.019 0.889 2011-2012 1.013 1.041 1.007 1.006 1.054 2012-2013 1.039 0.938 1.022 1.016 0.974 2013-2014 1.007 1.011 0.994 1.013 1.018 2014-2015 0.966 1.062 0.978 0.987 1.026 2015-2016 0.918 1.435 0.962 0.954 1.317 2016-2017 0.901 0.977 0.903 0.998 0.881 Mean 0.995 1.046 0.997 0.997 1.035 From Table 2, specific analysis shows that the technical efficiency can be decomposed into the product of pure technical efficiency and scale efficiency. From 2007 to 2008, the technical efficiency declined, the change of pure technical efficiency was less than 1, and the change of scale efficiency was greater than 1. Therefore, the energy efficiency. 2009-2010 and 2014-2017 technical efficiency drops, pure technical efficiency and scale efficiency changes are less than 1, therefore during the pure technical efficiency and scale efficiency drops to hinder the improvement of energy efficiency, in the meantime the city failed to embody the effect of industrial energy efficiency. 2009-2010 and 2014-2017 technical efficiency drops, pure technical efficiency and scale efficiency changes are less than 1, therefore during the pure technical efficiency and scale efficiency drops to hinder the improvement of energy efficiency, in the meantime the city failed to embody the effect of industrial structure optimization, to focus on industrial structure optimization of input-output efficiency. energy efficiency. 2009-2010 and 2014-2017 technical efficiency drops, pure technical efficiency and scale efficiency changes are less than 1, therefore during the pure technical efficiency and scale efficiency drops to hinder the improvement of energy efficiency, in the meantime the city failed to embody the effect of industrial structure optimization, to focus on industrial structure optimization of input-output efficiency. From Table 2, specific analysis shows that the technical efficiency can be decomposed into the product of pure technical efficiency and scale efficiency. 3.1 Analysis of China's urban energy efficiency measurement results Using DEA -- Solver Pro 5.0 to measure the energy efficiency of Chinese cities, the energy efficiency of each city from 2006 to 2017 can be obtained. In order to clearly express the distribution of energy efficiency, ArcGIS software is used. According to Jenks natural breakpoint classification method, 266 cities were divided into high efficiency area, high efficiency area, low efficiency area and low efficiency area. Due to space constraints, in order to further analyze the change of energy efficiency, the energy efficiency of each city in 2006 and 2017 is shown in Figure 1. Table 1. Selection of indicators for measuring energy efficiency in Chinese cities and data description. Table 1. Selection of indicators for measuring energy efficiency in Chinese cities and data description. Table 1. Selection of indicators for measuring energy efficiency in Chinese cities and data description. Table 1. Selection of indicators for measuring energy efficiency in Chinese cities and data description. Indicators Describe Input index Labor input Number of urban employees at year-end Capital investment Capital stock (adjusted for 2005) The energy input Electricity consumption by the whole society Table 1. Selection of indicators for measuring energy efficiency in Chinese cities and data description. Indicators Describe Input index Labor input Number of urban employees at year-end Capital investment Capital stock (adjusted for 2005) The energy input Electricity consumption by the whole society 2 2 https://doi.org/10.1051/e3sconf/202126101020 E3S Web of Conferences 261, 01020 (2021) E3S Web of Conferences 261, 01020 (2021) ICEMEE 2021 Fig. 1. Comparison of urban energy efficiency in 2006 and 2017. Fig. 1. Comparison of urban energy efficiency in 2006 and 2017. As can be seen from Figure 1, in 2006, most of the high-efficiency areas were distributed in the northeast and southeast coastal areas. In the central region, except for some cities in the high-efficiency area and the high- efficiency area, most of the provinces were in the low- efficiency area and the low-efficiency area. From the overall space, there was a phenomenon of agglomeration of low-efficiency areas. The number of cities with high efficiency in 2017 was significantly more than that in 2006. The number of cities with high efficiency in northeast China increased, but the number of cities with high efficiency in southeast coastal China decreased, and the number of cities with high efficiency in central China increased, showing the agglomeration of high efficiency areas or high efficiency areas. 3.2 Decomposition of urban energy efficiency in China From 2007 to 2008, the technical efficiency declined, the change of pure technical efficiency was less than 1, and the change of scale efficiency was greater than 1. Therefore, the decline of pure technical efficiency during this period hindered the improvement of energy efficiency, indicating that the lack of technological development impetus in each city during this period was the reason for the decrease of 3 3 https://doi.org/10.1051/e3sconf/202126101020 E3S Web of Conferences 261, 01020 (2021) ICEMEE 2021 E3S Web of Conferences 261, 01020 (2021) 4 Conclusions and policy recommendations (1) From time comparison, it can be seen that in 2006, most of the high efficiency areas were distributed in the northeast and southeast coastal areas, while most of the other provinces were in low efficiency and low efficiency areas, and there was a phenomenon of agglomeration of low efficiency areas. In 2017, the number of cities with high efficiency areas increased, and the central region showed the agglomeration phenomenon of high efficiency areas or high efficiency areas. (2) From the decomposition of urban energy efficiency, it can be seen that technological progress is the main driving force of urban energy efficiency improvement, and the decline of technical efficiency inhibits the improvement of urban energy efficiency. Therefore, the following suggestions are proposed. Promote regional coordinated development, and promote the overall energy efficiency of the central region in the way that high-efficiency zones drive surrounding areas. The southeast coastal areas should pay attention to the coordination and cooperation with the population policy and employment policy and give full play to the synergistic effect of the policies. Technological progress is the main driving force for energy efficiency, and technological innovation in energy utilization, pollution control and recycling should be strengthened. 5. Betsill, M., and M. J. Hoffmann. REV POLICY RES.28,83-106, (2011). Reference 1. M. Antonino, H. Lisanne, H. Oliver, F.Jimeno, G.Niki, R. Diana. RENEW SUST ENERG REV.124, (2020). 2. W. Guan, S. Xu. J. Geogr. Sci.06, 980-992 (2015). 3. Albrizio, S.,T. Kozluk, and Zipperer. J Environ Econ Manage81, 209-226, (2017). 4. Allen, F., J. Qian, and M. Qian. J financ econ77, 57- 116, (2005). 5. Betsill, M., and M. J. Hoffmann. REV POLICY RES.28,83-106, (2011). 5. Betsill, M., and M. J. Hoffmann. REV POLICY RES.28,83-106, (2011). 4
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The upper bound estimation on the spectral norm of r-circulant matrices with the Fibonacci and Lucas numbers
Journal of inequalities and applications
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R ES EA RCH Open Access Chengyuan He*, Jiangming Ma, Kunpeng Zhang and Zhenghua Wang *Correspondence: chengyuanh@163.com School of Mathematics and Computer Engineering, Xihua University Chengdu, Sichuan, 610039, P.R. China Abstract Let us define A = Circr(a0,a1,...,an–1) to be a n × n r-circulant matrix. The entries in the first row of A = Circr(a0,a1,...,an–1) are ai = Fi, or ai = Li, or ai = FiLi, or ai = F2 i , or ai = L2 i (i = 0,1,...,n – 1), where Fi and Li are the ith Fibonacci and Lucas numbers, respectively. This paper gives an upper bound estimation of the spectral norm for r-circulant matrices with Fibonacci and Lucas numbers. The result is more accurate than the corresponding results of S Solak and S Shen, and of J Cen, and the numerical examples have provided further proof. Keywords: r-circulant matrices; Fibonacci number; Lucas number; spectral norm; estimation Keywords: r-circulant matrices; Fibonacci number; Lucas number; spectral norm; estimation He et al. Journal of Inequalities and Applications ( 2015) 2015:72 DOI 10.1186/s13660-015-0596-5 He et al. Journal of Inequalities and Applications ( 2015) 2015:72 DOI 10.1186/s13660-015-0596-5 The upper bound estimation on the spectral norm of r-circulant matrices with the Fibonacci and Lucas numbers Chengyuan He*, Jiangming Ma, Kunpeng Zhang and Zhenghua Wang *Correspondence: chengyuanh@163.com School of Mathematics and Computer Engineering, Xihua University Chengdu, Sichuan, 610039, P.R. China 1 Introduction 1 Introduction For n > , the Fibonacci sequence {Fn} is defined by Fn+= Fn + Fn–, where F= and F= . If we start by zero, then the sequence is given by For n > , the Fibonacci sequence {Fn} is defined by Fn+= Fn + Fn–, where F= and F= . If we start by zero, then the sequence is given by n          ··· Fn          ··· () () If we deduce from Fn+that Ln+= Ln + Ln–, and let L= , L= , then we obtain the Lucas sequence {Ln}, n          ··· Ln          ··· () n          ··· Ln          ··· () n          ··· Ln          ··· () () Furthermore, the sequences {Fn} and {Ln} satisfy the following recursion: Fn + Ln = Fn+. () () Fn + Ln = Fn+. Definition .A matrix A is an r-circulant matrix if it is of the form Definition .A matrix A is an r-circulant matrix if it is of the form A = ⎛ ⎜⎜⎜⎜⎜⎜⎝ a a ··· an– an– ran– a ··· an– an– ··· ··· ··· ··· ··· ra ra ··· a a ra ra ··· ran– a ⎞ ⎟⎟⎟⎟⎟⎟⎠ . © 2015 He et al.; licensee Springer. This is an Open Access article distributed under the terms of the Creative Commons Attribu- tion License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. He et al. Journal of Inequalities and Applications ( 2015) 2015:72 He et al. Journal of Inequalities and Applications ( 2015) 2015:72 Page 2 of 10 Obviously, the elements of this r-circulant matrix are determined by its first row ele- ments a,a,...,an–and the parameter r, thus we denote A = Circr(a,a,...,an–). Espe- cially when r = , we obtain A = Circ(a,a,...,an–). Definition .A matrix A is called a symmetric r-circulant matrix if it is of the form A = ⎛ ⎜⎜⎜⎜⎜⎜⎝ a a ··· an– an– a a ··· an– ra ··· ··· ··· ··· ··· an– an– ··· ran– ran– an– ra ··· ran– ran– ⎞ ⎟⎟⎟⎟⎟⎟⎠ . Obviously, the elements of this r-circulant matrix are determined by its first row ele- ments a,a,...,an–and the parameter r; thus we denote A = SCircr(a,a,...,an–). Es- pecially when r = , we obtain A = SCirc(a,a,...,an–). For any A = (aij)m×n, the well-known spectral norm of the matrix A is For any A = (aij)m×n, the well-known spectral norm of the matrix A is ∥A∥=  max ≤i≤nλi AHA , ∥A∥=  max ≤i≤nλi AHA , in which λi(AHA) is the eigenvalue of AHA and AH is the conjugate transpose of matrix A. Define the maximum column length norm c(·) and the maximum row length norm r(·) of any matrix A by in which λi(AHA) is the eigenvalue of AHA and AH is the conjugate transpose of matrix A. Define the maximum column length norm c(·) and the maximum row length norm r(·) of any matrix A by c(A) = max j i |aij| and and r(A) = max i j |aij|, r(A) = max i j |aij|, espectively. respectively. respectively. Let A, B, and C be m × n matrices. If A = B ◦C, then in accordance with [] we have ∥A∥≤r(B)c(C) () ∥A∥≤r(B)c(C) () and and ∥A∥≤∥B∥∥C∥. () ∥A∥≤∥B∥∥C∥. () Here, we define B = (bij)m×n, C = (cij)m×n, and we let B ◦C be the Hadamard product of B and C. In recent years, many authors (see [–]) were concerned with r-circulant matrices as- sociated with a number sequence. References [–] calculate and estimate the Frobenius norm and the spectral norm of a circulant matrix where the elements of the r-circulant matrix are Fibonacci numbers and Lucas numbers; the authors found more accurate re- sults of the upper bound estimated, and the numerical examples also have provided further proof. He et al. Journal of Inequalities and Applications ( 2015) 2015:72 Page 3 of 10 Theorem .(see []) Let A = Circ(F,F,...,Fn–) be a circulant matrix, then we have Theorem .(see []) Let A = Circ(F,F,...,Fn–) be a circulant matrix, then we have ∥A∥≤FnFn–, ∥A∥≤FnFn–, where ∥· ∥is the spectral norm and Fn denotes the nth Fibonacci number. Theorem .(see []) Let A = Circ(L,L,...,Ln–) be a circulant matrix, then we have ∥A∥≤ ⎧ ⎨ ⎩  [FnFn–+ F n–+ Fn–Fn–+ ] × [FnFn–+ F n–+ Fn–Fn–+ ], n odd,  [FnFn–+ F n–+ Fn–Fn–] × [FnFn–+ F n–+ Fn–Fn–– ], n even, where ∥· ∥is the spectral norm, and Ln and Fn denote the nth Lucas and Fibonacci num- bers, respectively. where ∥· ∥is the spectral norm, and Ln and Fn denote the nth Lucas and Fibonacci num- bers, respectively. Theorem .(see []) Let A = Circr(F,F,...,Fn–) be a r-circulant matrix, in which |r| ≥, and then Theorem .(see []) Let A = Circr(F,F,...,Fn–) be a r-circulant matrix, in which |r| ≥, and then ∥A∥≤|r|FnFn–, where r ∈C, ∥· ∥is the spectral norm and Fn denotes the nth Fibonacci number. Theorem .(see []) Let A = Circr(L,L,...,Ln–) be a r-circulant matrix and |r| ≥, then we obtain ∥A∥≤ ⎧ ⎨ ⎩  (|r|FnFn–+ )(FnFn–+ ), n odd,  [|r|FnFn–+ (– |r|)](FnFn–– ), n even, where r ∈C, ∥· ∥is the spectral norm, and Ln and Fn denote the nth Lucas and Fibonacci numbers, respectively. where r ∈C, ∥· ∥is the spectral norm, and Ln and Fn denote the nth Lucas and Fibonacci numbers, respectively. we get A = B ◦C. 2 Main results Theorem .Let A = Circ(F,F,...,Fn–) be a circulant matrix, then we have ∥A∥≤  (n – )FnFn–, where ∥· ∥is the spectral norm and Fn denotes the nth Fibonacci number. Proof Since A = Circ(F,F,...,Fn–) is a circulant matrix, let the matrices B and C be Proof Since A = Circ(F,F,...,Fn–) is a circulant matrix, let the matrices B and C be B = ⎛ ⎜⎜⎜⎝ F  ···   F ···  ··· ··· ··· ···   ··· F ⎞ ⎟⎟⎟⎠, C = ⎛ ⎜⎜⎜⎜⎜⎜⎝ F F ··· Fn– Fn– Fn– F ··· Fn– Fn– ··· ··· ··· ··· ··· F F ··· F F F F ··· Fn– F ⎞ ⎟⎟⎟⎟⎟⎟⎠ , B = ⎛ ⎜⎜⎜⎝ F  ···   F ···  ··· ··· ··· ···   ··· F ⎞ ⎟⎟⎟⎠, C = ⎛ ⎜⎜⎜⎜⎜⎜⎝ F F ··· Fn– Fn– Fn– F ··· Fn– Fn– ··· ··· ··· ··· ··· F F ··· F F F F ··· Fn– F ⎞ ⎟⎟⎟⎟⎟⎟⎠ , we get A = B ◦C. we get A = B ◦C. He et al. Journal of Inequalities and Applications ( 2015) 2015:72 Page 4 of 10 For r(B) = max i j |bij|= √ n –  and For r(B) = max i j |bij|= √ n –  and c(C) = max j i |cij|= max j     n i= |cin|=     n– s= Fs =  FnFn–. From (), we have ∥A∥≤  (n – )FnFn–. □ ∥A∥≤  (n – )FnFn–. ∥A∥≤  (n – )FnFn–. □ □ Corollary .Let A = SCirc(F,F,...,Fn–) be a symmetric circulant matrix, then we have ∥A∥≤  (n – )FnFn–, Corollary .Let A = SCirc(F,F,...,Fn–) be a symmetric circulant matrix, then we have ∥A∥≤  (n – )FnFn–, Corollary .Let A = SCirc(F,F,...,Fn–) be a symmetric circulant matrix, then we have ∥A∥≤  (n – )FnFn–, ∥A∥≤  (n – )FnFn–, where ∥· ∥is the spectral norm and Fn denotes the nth Fibonacci number. where ∥· ∥is the spectral norm and Fn denotes the nth Fibonacci number. where ∥· ∥is the spectral norm and Fn denotes the nth Fibonacci number. 2 Main results Corollary .Let A = Circ(F ,F ,...,F n–) be a circulant matrix, then we have ∥A∥≤(n – )FnFn–, Corollary .Let A = Circ(F ,F ,...,F n–) be a circulant matrix, then we have ∥A∥≤(n – )FnFn–, ∥A∥≤(n – )FnFn–, where ∥· ∥is the spectral norm and Fn denotes the nth Fibonacci number. where ∥· ∥is the spectral norm and Fn denotes the nth Fibonacci number. Proof Since A = Circ(F ,F ,...,F n–) is a circulant matrix, if the matrices B = Circ(F,F, ...,Fn–), we get A = B ◦B; thus from () and Theorem .we obtain ∥A∥≤(n – )FnFn–. □ □ ∥A∥≤(n – )FnFn–. Theorem .Let A = Circ(L,L,...,Ln–) be a circulant matrix, then we have ∥A∥≤ ⎧ ⎨ ⎩ √nFnFn–+ n, n odd, √nFnFn–, n even, where ∥· ∥is the spectral norm and Ln denotes the Lucas number. where ∥· ∥is the spectral norm and Ln denotes the Lucas number. Proof Since A = Circ(L,L,...,Ln–) is a circulant matrix, let the following matrices be defined: B = ⎛ ⎜⎜⎜⎝   ···    ···  ··· ··· ··· ···   ···  ⎞ ⎟⎟⎟⎠, C = ⎛ ⎜⎜⎜⎜⎜⎜⎝ L L ··· Ln– Ln– Ln– L ··· Ln– Ln– ··· ··· ··· ··· ··· L L ··· L L L L ··· Ln– L ⎞ ⎟⎟⎟⎟⎟⎟⎠ , then A = B ◦C. then A = B ◦C. He et al. Journal of Inequalities and Applications ( 2015) 2015:72 Page 5 of 10 Page 5 of 10 We have r(B) = max i j |bij|= √n We have and Here n– s= F s = FnFn–, n– s= FsFs–= ⎧ ⎨ ⎩ F n–, n odd, F n–– , n even, n– s= F s–= Fn–Fn–+ , thus c(C) = ⎧ ⎨ ⎩ √FnFn–+ , n odd, √FnFn–, n even, c(C) = ⎧ ⎨ ⎩ √FnFn–+ , n odd, √FnFn–, n even, and from () we obtain and from () we obtain ∥A∥≤ ⎧ ⎨ ⎩ √nFnFn–+ n, n odd, √nFnFn–, n even. □ □ Corollary .Let A = SCirc(L,L,...,Ln–) be a symmetric circulant matrix, then we have Corollary .Let A = SCirc(L,L,...,Ln–) be a symmetric circulant matrix, then we have ∥A∥≤ ⎧ ⎨ ⎩ √nFnFn–+ n, n odd, √nFnFn–, n even, ∥A∥≤ ⎧ ⎨ ⎩ √nFnFn–+ n, n odd, √nFnFn–, n even, where ∥· ∥is the spectral norm, and Ln and Fn denote the nth Lucas and Fibonacci num- bers, respectively. where ∥· ∥is the spectral norm, and Ln and Fn denote the nth Lucas and Fibonacci num- bers, respectively. Corollary .Let A = Circ(L ,L ,...,L n–) be circulant matrices, then Corollary .Let A = Circ(L ,L ,...,L n–) be circulant matrices, then ∥A∥≤ ⎧ ⎨ ⎩ nFnFn–+ n, n odd, nFnFn–, n even, ∥A∥≤ ⎧ ⎨ ⎩ nFnFn–+ n, n odd, nFnFn–, n even, ∥A∥≤ ⎧ ⎨nFnFn–+ n, n odd, where ∥· ∥is the spectral norm, and Ln and Fn denote the nth Lucas and Fibonacci num- bers, respectively. where ∥· ∥is the spectral norm, and Ln and Fn denote the nth Lucas and Fibonacci num- bers, respectively. where ∥· ∥is the spectral norm and Ln denotes the Lucas number. Proof Since A = Circ(L ,L ,...,L n–) is a circulant matrix, if the matrices B = Circ(L,L, ...,Ln–), we get A = B ◦B; thus from () and Theorem ., we obtain ∥A∥≤ ⎧ ⎨ ⎩ nFnFn–+ n, n odd, nFnFn–, n even. ∥A∥≤ ⎧ ⎨ ⎩ nFnFn–+ n, n odd, nFnFn–, n even. □ ∥A∥≤ ⎧ ⎨nFnFn–+ n, n odd, □ He et al. Journal of Inequalities and Applications ( 2015) 2015:72 Page 6 of 10 Corollary .Let A = Circ(FL,FL,...,Fn–Ln–) be circulant matrices, then Corollary .Let A = Circ(FL,FL,...,Fn–Ln–) be circulant matrices, then ∥A∥≤ ⎧ ⎨ ⎩ √(n – )nFnFn–(FnFn–+ ), n odd, √(n – )nFnFn–, n even, ∥A∥≤ ⎧ ⎨ ⎩ √(n – )nFnFn–(FnFn–+ ), n odd, √(n – )nFnFn–, n even, A∥≤ ⎧ ⎨√(n – )nFnFn–(FnFn–+ ), n odd, where ∥· ∥is the spectral norm, and Ln and Fn denote the nth Lucas and Fibonacci num- bers, respectively. where ∥· ∥is the spectral norm, and Ln and Fn denote the nth Lucas and Fibonacci num- bers, respectively. Proof Since A = Circ(FL,FL,...,Fn–Ln–) is a circulant matrix, if the matrices B = Circ(F,F,...,Fn–) and C = Circ(L,L,...,Ln–), we get A = B ◦C; thus from (), The- orems ., and ., we obtain ∥A∥≤ ⎧ ⎨ ⎩ √(n – )nFnFn–(FnFn–+ ), n odd, √(n – )nFnFn–, n even. □ □ Theorem .Let A = Circr(F,F,...,Fn–) be a r-circulant matrix, in which |r| ≥, and then ∥A∥≤  (n – )|r|FnFn–, where r ∈C, ∥· ∥is the spectral norm and Fn denotes the nth Fibonacci number. Proof Since A = Circr(F,F,...,Fn–) is a r-circulant matrix, let B and C, respectively, be Proof Since A = Circr(F,F,...,Fn–) is a r-circulant matrix, let B and C, respectively, be B = ⎛ ⎜⎜⎜⎜⎜⎜⎝ F   ···  r F  ···  r r F ···  ··· ··· ··· ··· ··· r r r ··· F ⎞ ⎟⎟⎟⎟⎟⎟⎠ , C = ⎛ ⎜⎜⎜⎜⎜⎜⎝ F F F ··· Fn– Fn– F F ··· Fn– Fn– Fn– F ··· Fn– ··· ··· ··· ··· ··· F F F ··· F ⎞ ⎟⎟⎟⎟⎟⎟⎠ , then A = B ◦C. where ∥· ∥is the spectral norm and Ln denotes the Lucas number. For For r(B) = max i j |bij|=  (n – )|r| and r(B) = max i j |bij|=  (n – )|r| and c(C) = max j i |cij|=     n i= |cin|=     n– s= Fs =  FnFn–, from (), we have from (), we have □ ∥A∥≤  (n – )|r|FnFn–. He et al. Journal of Inequalities and Applications ( 2015) 2015:72 Page 7 of 10 Corollary .Let A = SCircr(F,F,...,Fn–) be a symmetric r-circulant matrix, in which |r| ≥, and then ∥A∥≤  (n – )|r|FnFn–, where r ∈C, ∥· ∥is the spectral norm and Fn denotes the nth Fibonacci number. Corollary .Let A = Circr(F ,F ,...,F n–) be a r-circulant matrix, while |r| ≥, then we obtain ∥A∥≤(n – )|r|FnFn–, where r ∈C, ∥· ∥is the spectral norm and Fn denotes the Fibonacci number. Proof Since A = Circr(F ,F ,...,F n–) is a r-circulant matrix, if the matrices B = Circr(F, F,...,Fn–) and C = Circ(F,F,...,Fn–), we get A = B ◦C; thus from (), Theorems ., and ., we obtain ∥A∥≤(n – )|r|FnFn–. □ ∥A∥≤(n – )|r|FnFn–. □ Corollary .Let A = Circr(FL,FL,...,Fn–Ln–) be a r-circulant matrix, while |r| ≥, then we obtain ∥A∥≤ ⎧ ⎨ ⎩  (n – )n|r|FnFn–(FnFn–+ ), n odd, FnFn–  |r|(n – )n, n even, ∥A∥≤ ⎧ ⎨ ⎩  (n – )n|r|FnFn–(FnFn–+ ), n odd, FnFn–  |r|(n – )n, n even, where r ∈C, ∥· ∥is the spectral norm, and Ln and Fn denote the nth Lucas and Fibonacci numbers, respectively. where r ∈C, ∥· ∥is the spectral norm, and Ln and Fn denote the nth Lucas and Fibonacci numbers, respectively. Proof Since A = Circr(FL,FL,...,Fn–Ln–) is a r-circulant matrix, if the matrices B = Circr(F,F,...,Fn–) and C = Circ(L,L,...,Ln–), we get A = B ◦C; thus from (), Theo- rems ., and ., we obtain ∥A∥≤ ⎧ ⎨ ⎩  (n – )n|r|FnFn–(FnFn–+ ), n odd, FnFn–  |r|(n – )n, n even. where ∥· ∥is the spectral norm and Ln denotes the Lucas number. □ □ Theorem .Let A = Circr(L,L,...,Ln–) be a r-circulant matrix and |r| ≥, then we obtain Theorem .Let A = Circr(L,L,...,Ln–) be a r-circulant matrix and |r| ≥, then we obtain ∥A∥≤ ⎧ ⎨ ⎩  (n – )|r|+ × √FnFn–+ , n odd,  (n – )|r|+ × √FnFn–, n even, where r ∈C, ∥· ∥is the spectral norm, and Ln and Fn denote the nth Lucas and Fibonacci numbers, respectively. He et al. Journal of Inequalities and Applications ( 2015) 2015:72 Page 8 of 10 He et al. Journal of Inequalities and Applications ( 2015) 2015:72 Page 8 of 10 He et al. Journal of Inequalities and Applications ( 2015) 2015:72 Page 8 of 10 Page 8 of 10 Proof Since A = Circr(L,L,...,Ln–) is a r-circulant matrix, let B and C, respectively, be Proof Since A = Circr(L,L,...,Ln–) is a r-circulant matrix, let B and C, respectively, be B = ⎛ ⎜⎜⎜⎜⎜⎜⎝    ···  r   ···  r r  ···  ··· ··· ··· ··· ··· r r r ···  ⎞ ⎟⎟⎟⎟⎟⎟⎠ , C = ⎛ ⎜⎜⎜⎜⎜⎜⎝ L L ··· Ln– Ln– Ln– L ··· Ln– Ln– ··· ··· ··· ··· ··· L L ··· L L L L ··· Ln– L ⎞ ⎟⎟⎟⎟⎟⎟⎠ , and then A = B ◦C. We have and then A = B ◦C. We have and then A = B ◦C. We have and then A = B ◦C. and then A = B ◦C. where ∥· ∥is the spectral norm and Ln denotes the Lucas number. Proof Since A = Circr(L ,L ,...,L n–) is a r-circulant matrix, if the matrices B = Circ(L,L, ...,Ln–) and C = Circr(L,L,...,Ln–), we get A = B ◦C; thus from (), Theorems ., and ., we obtain ∥A∥≤ ⎧ ⎨ ⎩ (FnFn–+ )  n[(n – )|r|+ ], n odd, FnFn–  n[(n – )|r|+ ], n even. □ □ ⎨ ⎩FnFn–  n[(n – )|r|+ ], n even. where ∥· ∥is the spectral norm and Ln denotes the Lucas number. We have We have r(B) = max i j |bij|=  (n – )|r|+  and c(C) = max j i |cij|=     n i= |cin|=     n– s= Ls =     n– s= (Fs + Fs–), n which n– s= F s = FnFn–, n– s= Fs–Fs = ⎧ ⎨ ⎩ F n–, n odd, F n–– , n even, n– s= F s–= Fn–Fn–+ , c(C) = max j i |cij|=     n i= |cin|=     n– s= Ls =     n– s= (Fs + Fs–), in which n– s= F s = FnFn–, n– s= Fs–Fs = ⎧ ⎨ ⎩ F n–, n odd, F n–– , n even, n– s= F s–= Fn–Fn–+ , and we get and we get and we get c(C) = ⎧ ⎨ ⎩ √FnFn–+ , n odd, √FnFn–, n even. From (), we further infer From (), we further infer From (), we further infer From (), we further infer ∥A∥≤ ⎧ ⎨ ⎩  (n – )|r|+ × √FnFn–+ , n odd,  (n – )|r|+ × √FnFn–, n even. □ □ Corollary .Let A = SCircr(L,L,...,Ln–) be a symmetric r-circulant matrix and |r| ≥, then we obtain ∥A∥≤ ⎧ ⎨ ⎩  (n – )|r|+ × √FnFn–+ , n odd,  (n – )|r|+ × √FnFn–, n even, where r ∈C, ∥· ∥is the spectral norm, and Ln and Fn denote the nth Lucas and Fibonacci numbers, respectively. Corollary .Let A = Circr(L ,L ,...,L n–) be a r-circulant matrix and |r| ≥, then ∥A∥≤ ⎧ ⎨ ⎩ (FnFn–+ )  n[(n – )|r|+ ], n odd, FnFn–  n[(n – )|r|+ ], n even, He et al. Journal of Inequalities and Applications ( 2015) 2015:72 Page 9 of 10 where r ∈C, ∥· ∥is the spectral norm, and Ln and Fn denote the nth Lucas and Fibonacci numbers, respectively. where r ∈C, ∥· ∥is the spectral norm, and Ln and Fn denote the nth Lucas and Fibonacci numbers, respectively. 3 Examples Example Let A = Circ(F,F,...,Fn–) be a circulant matrix, in which Fi (i = ,,...,n–) denotes the Fibonacci number. From Table , it is easy to find that the upper bounds for the spectral norm, of Theo- rem .are more accurate than Theorem .when n ≥. Example Let A = Circ(L,L,...,Ln–) be a circulant matrix, where Li (i = ,,...,n – ) denotes the Lucas sequence. Let n ≥, and it is easy to find that the upper bounds for the spectral norm of Theo- rem .are more accurate than Theorem .(see Table ). Example Let A = Circ(F,F,...,Fn–) be a -circulant matrix, in which Fi (i = ,,...,n – ) denotes the Fibonacci number. Let n ≥, and it is easy to find that the upper bounds for the spectral norm of Theo- rem .are more precise than Theorem .(see Table ). Table 1 Numerical results of ai = Fi, r = 1 n Theorem 2.1 Theorem 1.3 Third column Second column 2 1 1 1 1 = 1 3 2 2 2 2 = 1 4 3 √ 2 6 6 3 √ 2 = √ 2 5 √ 60 15 15 √ 60 ≈1.936 6 √ 200 40 40 √ 200 = 2 √ 2 n √(n – 1)FnFn–1 FnFn–1 FnFn–1 √ (n–1)FnFn–1 =  FnFn–1 n–1 Table 1 Numerical results of ai = Fi, r = 1 n Theorem 2.1 Theorem 1.3 Third column Second column 2 1 1 1 1 = 1 3 2 2 2 2 = 1 4 3 √ 2 6 6 3 √ 2 = √ 2 5 √ 60 15 15 √ 60 ≈1.936 6 √ 200 40 40 √ 200 = 2 √ 2 n √(n – 1)FnFn–1 FnFn–1 FnFn–1 √ (n–1)FnFn–1 =  FnFn–1 n–1 Acknowledgements Acknowledgements Project supported by Applied Fundamental Research Plan of Sichuan Province (No. 2013JY0178). Acknowledgements Project supported by Applied Fundamental Research Plan of Sichuan Province (No. 2013JY0178). Received: 25 September 2014 Accepted: 12 February 2015 Received: 25 September 2014 Accepted: 12 February 2015 Table 4 Numerical results of ai = Li, r = 2 Table 4 Numerical results of ai = Li, r = 2 n Theorem 2.12 Theorem 1.6 Third column Second column 1 2 2 2 2 = 1 2 5 4 4 5 = 4 5 3 3 √ 14 2 √ 231 2 √ 231 3 √ 14 ≈2.708 4 √ 390 54 54 √ 390 ≈2.734 5 √1,343 152 152 √1,343 ≈4.418 6 10 √ 42 394 394 10 √ 342 ≈6.080 n Theorem 2.12 Theorem 1.6 Third column Second column 1 2 2 2 2 = 1 2 5 4 4 5 = 4 5 3 3 √ 14 2 √ 231 2 √ 231 3 √ 14 ≈2.708 4 √ 390 54 54 √ 390 ≈2.734 5 √1,343 152 152 √1,343 ≈4.418 6 10 √ 42 394 394 10 √ 342 ≈6.080 Example Let A = Circ(L,L,...,Ln–) be a -circulant matrix where Li (i = ,,..., n – ) denotes the Lucas sequence. Example Let A = Circ(L,L,...,Ln–) be a -circulant matrix where Li (i = ,,..., n – ) denotes the Lucas sequence. It can be seen from Table that the upper bounds for the spectral norm of Theorem . are more precise than Theorem .when n ≥. It can be seen from Table that the upper bounds for the spectral norm of Theorem . are more precise than Theorem .when n ≥. Competing interests Competing interests The authors declare that they have no competing interests. Competing interests The authors declare that they have no competing interests. Authors’ contributions All authors contributed equally to the writing of this paper. All authors read and approved the final manuscript. Table 2 Numerical results of ai = Li, r = 1 n Theorem 2.4 Theorem 1.4 Third column Second column 1 2 2 2 2 = 1 2 √ 10 √ 10 √ 10 √ 10 = 1 3 √ 42 √ 154 √ 154 √ 42 ≈1.915 4 √ 120 √ 810 √ 810 √ 120 ≈2.598 5 √ 395 √6,004 √6,004 √ 395 ≈3.899 6 √1,200 √39,400 √39,400 √1,200 ≈5.730 n  n–1(5FnFn–1 + 1) n odd,  n–1(5FnFn–1 – 3) n even He et al. Journal of Inequalities and Applications ( 2015) 2015:72 Page 10 of 10 Table 3 Numerical results of ai = Fi, r = 2 n Theorem 2.8 Theorem 1.5 Third column Second column 2 2 2 2 2 = 1 3 4 4 4 4 = 1 4 6 √ 2 12 12 6 √ 2 = √ 2 5 4 √ 15 √ 30 30 4 √ 15 ≈1.936 6 20 √ 2 80 80 20 √ 2 = 2 √ 2 n  (n – 1)|r|2FnFn–1 |r|FnFn–1  (n – 1)–1FnFn–1 Table 4 Numerical results of ai = Li, r = 2 References References 1. Mathias, R: The spectral norm of a nonnegative matrix. Linear Algebra Appl. 131, 269-284 (1990) 1. Mathias, R: The spectral norm of a nonnegative matrix. Linear Algebra Appl. 131, 269-284 (1990) 1. Mathias, R: The spectral norm of a nonnegative matrix. Linear Algebra Appl. 131, 269 284 (1990) 2. Solak, S: On the norms of circulant matrices with the Fibonacci and Lucas numbers. Appl. Math. Comput. 160, 125-132 (2005) 2. Solak, S: On the norms of circulant matrices with the Fibonacci and Lucas numbers. Appl. Math. Comput. 160, 125-132 (2005) 3 Solak, S: Erratum to ‘On the norms of circulant matrices with the Fibonacci and Lucas numbers’ [Appl Math Comput , pp p , (2005) 3. Solak, S: Erratum to ‘On the norms of circulant matrices with the Fibonacci and Lucas numbers’ [Appl. Math. Comput. 160 (2005) 125-132]. Appl. Math. Comput. 190, 1855-1856 (2007) (2005) 3. Solak, S: Erratum to ‘On the norms of circulant matrices with the Fibonacci and Lucas numbers’ [Appl. Math. Comput. 160 (2005) 125-132]. Appl. Math. Comput. 190, 1855-1856 (2007) pp p , 4. Shen, S, Cen, J: On the bounds for the norms of r-circulant matrices with the Fibonacci and Lucas numbers. Appl. Math. Comput. 216, 2891-2897 (2010) 5. Yazlik, Y, Taskara, N: On the norms of an r-circulant matrix with the generalized k-Horadam numbers. J. Inequal. Appl. 2013, 394 (2013) 6. Bozkurt, D, Tam, T-Y: Determinants and inverses of r-circulant matrices associated with a number sequence. Linear Multilinear Algebra (2014). doi:10.1080/03081087.2014.941291
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Clostridium butyricum Alleviates Enterotoxigenic Escherichia coli K88-Induced Oxidative Damage Through Regulating the p62-Keap1-Nrf2 Signaling Pathway and Remodeling the Cecal Microbial Community
Frontiers in immunology
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ORIGINAL RESEARCH published: 11 November 2021 doi: 10.3389/fimmu.2021.771826 ORIGINAL RESEARCH published: 11 November 2021 doi: 10.3389/fimmu.2021.771826 Haihua Li 1, Zhiyuan Shang 2, Xuejiao Liu 1, Yingying Qiao 3, Kewei Wang 2 and Jiayun Qiao 2* Edited by: Hongkui Wei, Huazhong Agricultural University, China Edited by: Hongkui Wei, Huazhong Agricultural University, China 1 Tianjin Key Laboratory of Agricultural Animal Breeding and Healthy Husbandry, College of Animal Science and Veterinary Medicine, Tianjin Agricultural University, Tianjin, China, 2 Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, Tianjin, China, 3 Faculty of Biology and Technology, Sumy National Agrarian University, Sumy, Ukraine Reviewed by: Marie Van Der Merwe, University of Memphis, United States Xia Xiong, Institute of Subtropical Agriculture (CAS), China Reviewed by: Marie Van Der Merwe, University of Memphis, United States Xia Xiong, Institute of Subtropical Agriculture (CAS), China Clostridium butyricum (CB) can enhance antioxidant capacity and alleviate oxidative damage, but the molecular mechanism by which this occurs remains unclear. This study used enterotoxigenic Escherichia coli (ETEC) K88 as a pathogenic model, and the p62-Keap1-Nrf2 signaling pathway and intestinal microbiota as the starting point to explore the mechanism through which CB alleviates oxidative damage. After pretreatment with CB for 15 d, mice were challenged with ETEC K88 for 24 h. The results suggest that CB pretreatment can dramatically reduce crypt depth (CD) and significantly increase villus height (VH) and VH/CD in the jejunum of ETEC K88-infected mice and relieve morphological lesions of the liver and jejunum. Additionally, compared with ETEC- infected group, pretreatment with 4.4×106 CFU/mL CB can significantly reduce malondialdehyde (MDA) level and dramatically increase superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels in the serum. This pretreatment can also greatly increase the mRNA expression levels of tight junction proteins and genes related to the p62-Keap1-Nrf2 signaling pathway in the liver and jejunum in ETEC K88-infected mice. Meanwhile, 16S rDNA amplicon sequencing revealed that Clostridium disporicum was significantly enriched after ETEC K88 challenge relative to the control group, while Lactobacillus was significantly enriched after 4.4×106 CFU/mL CB treatment. Furthermore, 4.4×106 CFU/mL CB pretreatment increased the short-chain fatty acid (SCFA) contents in the cecum of ETEC K88-infected mice. Moreover, we found that *Correspondence: Jiayun Qiao skyqjy@tjnu.edu.cn *Correspondence: Jiayun Qiao skyqjy@tjnu.edu.cn Specialty section: This article was submitted to Nutritional Immunology, a section of the journal Frontiers in Immunology Specialty section: This article was submitted to Nutritional Immunology, a section of the journal Frontiers in Immunology Received: 07 September 2021 Accepted: 28 October 2021 Published: 11 November 2021 Received: 07 September 2021 Accepted: 28 October 2021 Published: 11 November 2021 Abbreviations: CFU, Colony forming unit; PCR, Polymerase chain reaction; MDA, Malondialdehyde; SOD, Superoxide dismutase; GSH-Px, Glutathione peroxidase; qRT-PCR, Quantitative real-time polymerase chain reaction; ZO-1, Zonula occludens-1; HO-1, Heme oxygenase-1; ROS, Reactive oxygen species; RNS, Reactive nitrogen species; Nrf2, NF-E2-related factor 2; Keap1, Kelch-like ECH-associated protein-1; ARE, Antioxidant response element; SCFAs, Short- chain fatty acids; GAPDH, Glyceraldehyde-3-phosphate dehydrogenase; CTAB, Cetyltrimethyl Ammonium Bromide; OTU, Operational taxonomic unit; VH, Villus height; CD, Crypt depth; ATP, Adenosine triphosphate; LDA, Linear discriminant analysis. INTRODUCTION response element (ARE) signaling pathway is a redox sensitive signal system and can regulate the body in the redox state and maintain the body stability. Nrf2 can respond to oxidative stress, is an important transcription factor that regulates oxidative stress in cells, and promotes the production of proteins involved in anti- oxidativestress, thereby exertingan antioxidanteffect(10). Keap1is a regulator of oxidative stress that combines with Nrf2 in the cytoplasm to fix Nrf2 in the cytoplasm and combines with E3 ubiquitination ligase to promote the ubiquitination and degradation of Nrf2. When the body is subjected to oxidative stress, Keap1 is inactivated, inhibits the ubiquitination and degradation of Nrf2, promotes Nrf2 accumulation, activates Nrf2, enters the nucleus, binds with ARE, and induces transcription and expression of downstream antioxidant enzyme genes to activate the defense system and alleviate oxidative damage (11, 12). In addition, the crossregulation between the Keap1-Nrf2 pathway and autophagy can resist oxidative stress (12). p62 is a substrate and active molecule involved in autophagy that can competitively bind to Keap1 with Nrf2, promote Nrf2 nuclear transfer, activate the Nrf2/AREsignaling pathway,andthenexert antioxidanteffectsand maintain the body’s barrier function (11–13). And it has been pointed out that intestinal microbiota and their metabolites are part of the intestinal ecosystem, which together maintain the intestinal health of humans and animals. The host provides colonization sites for intestinal microbiota, and intestinal microbiota help the intestine resist invasion by harmful substances, such as pathogens (14).Intestinalmicrobiotacaninteractwiththehosttomaintainthe integrity of the tissue morphology and barrier function and promote intestinal health (14). Therefore, effective regulation of p62-Keap1-Nrf2signalingpathwayandrestorationormaintenance of intestinal microbiota may be an effective strategy to alleviate ETEC K88-induced oxidative damage. Oxidative stress occurs when the production rate offree radicals in the body [mainly reactive oxygen species (ROS) and reactive nitrogen species (RNS)] exceeds the elimination rate of the body’s antioxidant system, resulting in an imbalance in oxidant and antioxidant effects (1). This induces lipid peroxide production, cross-linking of DNA or RNA, oxidative impairment, and protein configuration changes, which can cause dysfunction and diseases of tissues and cells. Oxidative stress can occur in response to various conditions. For example, when pathogens invade the animal body, adenosine triphosphate (ATP) is produced through the electron transport chain to provide immune response, but the body also produces a large quantity of ROS, inducing oxidative stress (2, 3). Citation: Li H, Shang Z, Liu X, Qiao Y, Wang K and Qiao J (2021) Clostridium butyricum Alleviates Enterotoxigenic Escherichia coli K88-Induced Oxidative Damage Through Regulating the p62-Keap1-Nrf2 Signaling Pathway and Remodeling the Cecal Microbial Community. Front. Immunol. 12:771826. doi: 10.3389/fimmu.2021.771826 November 2021 | Volume 12 | Article 771826 Frontiers in Immunology | www.frontiersin.org Li et al. CB Alleviates Oxidative Damage Lachnoclostridium, Roseburia, Lactobacillus, Terrisporobacter, Akkermansia, and Bacteroides are closely related to SCFA contents and oxidative indicators. Taken together, 4.4×106 CFU/mL CB pretreatment can alleviate ETEC K88-induced oxidative damage through activating the p62-Keap1-Nrf2 signaling pathway and remodeling the cecal microbiota community in mice. Lachnoclostridium, Roseburia, Lactobacillus, Terrisporobacter, Akkermansia, and Bacteroides are closely related to SCFA contents and oxidative indicators. Taken together, 4.4×106 CFU/mL CB pretreatment can alleviate ETEC K88-induced oxidative damage through activating the p62-Keap1-Nrf2 signaling pathway and remodeling the cecal microbiota community in mice. Keywords: Clostridium butyricum, enterotoxigenic Escherichia coli K88, oxidative damage, p62-Keap1-Nrf2 signaling pathway, cecal microbiota, mice Keywords: Clostridium butyricum, enterotoxigenic Escherichia coli K88, oxidative damage, p62-Keap1-Nrf2 signaling pathway, cecal microbiota, mice INTRODUCTION Additionally, when a pathogen is ingested, glycolysis is activated to increase the consumption of molecular oxygen, which in turn promotes the accumulation of ROS (2, 3). Enterotoxigenic Escherichia coli (ETEC) K88 is a gram-negative bacterium with adhesive flagella that can attach to intestinal epithelial cells (IECs), promote secretion of pro-inflammatory factors by IECs, and cause intestinal inflammation (4). After colonization, ETEC can produce enterotoxins that damage intestinal epithelial cells, causing the spread of pathogens to other organs, such as the spleen and liver (5,6).Yacoubetal.(7)foundthatETECinfectionscanincreaseliver enzyme levels, and induce reversible and irreversible liver damage. An important feature of ETEC infection is breakdown of the oxidation/antioxidant balance accompanied by the appearance of ROS (8). ROS, which are the main cause of impairment of normal cells and tissues, have been shown to be an inevitable result of the developmentofvariousdiseases.StudieshaveshownthatETECcan promote the metabolism of methionine and cysteine, and produce toxic homocysteine, which induces oxidative stress in the body (9). Therefore, ETEC can cause oxidative stress in the animal body. Accordingly, relieving oxidative stress has become a potential method of reducing the symptoms of ETEC infection. Clostridium butyricum (CB)is a strict anaerobe that can resist acid and tolerate high temperatures. This organism can colonize the cecum and colon, and can produce beneficial substances including a variety of digestive enzymes, vitamin B, and short- chain fatty acids (SCFAs) in its metabolic process (15, 16). Zhao et al. (17) found that CB can effectively reduce the inflammatory response and epithelial barrier damage in Salmonella-infected chickens through in vivo and in vitro studies. Similarly, our previous study found that CB alleviated ETEC-induced inflammatory responses in weaned piglets, and confirmed that CB is a safe and effective feed additive (18). Additionally, studies have reported that CB can alleviate oxidative damage (19, 20), but its mechanism is still not very clear. Therefore, this study was conducted to establish a pathogenic model for mice challenged Recent studies have shown that the Kelch-like ECH-associated protein-1 (Keap1)-NF-E2-related factor 2 (Nrf2)/antioxidant November 2021 | Volume 12 | Article 771826 Frontiers in Immunology | www.frontiersin.org 2 CB Alleviates Oxidative Damage Li et al. Li et al. Sample Collection and Processing Sample Collection and Processing Blood was collected from the retrobulbar venous sinus of mice and placed in ice for 2–3 h. Next, sera were obtained by centrifugation at 7,000 rpm and 4°C for 20 min, after which samples were stored at −20°C until determination of oxidation indexes. After the blood was collected, the mice were sacrificed by cervical dislocation (note that they were fasted for 12 h before sacrifice, but they could drink freely before the blood was collected). The liver and jejunum tissues were then taken under aseptic conditions and divided into two parts. One part was fixed in 4% paraformaldehyde and stored at room temperature to be used for the observation of shape and structure of tissue, while the other was put in a Ziplock bag and then immediately placed into liquid nitrogen. Samples were then moved to a −80°C freezer and stored until subsequent determination of the mRNA expression levels of the target gene. The cecum contents were collected under aseptic conditions, placed in a 1.5 mL centrifuge tube, and stored in a refrigerator at −80°C until use for the determination of SCFAs and the extraction of intestinal genomic DNA. Experiment 2 Effects of CB on Growth Performance in Mice Forty-eight mice were randomly divided into three groups [control group (CONT), low-dose group (L-CB), and high- dose group (H-CB)], with sixteen replicates in each group. The mice in the CONT group were gavaged with 0.2 mL normal saline, while those in the L-CB group were gavaged with 0.2 mL 4.4 × 105 CFU/mL CB and those in the H-CB group were gavaged with 0.2 ml 4.4 × 106 CFU/mL CB. All of the mice were gavaged once daily at 13:00 for 15 d. The weight of the mice was recorded on days 0, 7, and 14, after which the optimal concentration of CB was selected. INTRODUCTION were gavaged with 0.2 mL normal saline on days 1-15 and with 0.2 mL 3.7 × 108 CFU/mL ETEC K88 on day 16; mice in the L- CB group were gavaged with 0.2 mL 4.4 × 105 CFU/mL CB on days 1-16; mice in the H-CB group were gavaged with 0.2 mL 4.4 × 106 CFU/mL CB on days 1-16; mice in the L-CB+H-ETEC group were gavaged with 0.2 mL 4.4 × 105 CFU/mL CB on days 1–15 and with 0.2 mL 3.7 × 108 CFU/mL ETEC K88 on day 16; mice in the H-CB+H-ETEC group were gavaged with 0.2 mL 4.4 × 106 CFU/mL CB on days 1–15 and 0.2 mL 3.7×108 CFU/ mL ETEC K88 on day 16. Six mice with similar body weight were randomly selected and sacrificed in each group at 24 h after ETEC K88 challenge. The morphological structures of the liver and jejunum were observed, and the serum oxidation indexes and mRNA expression levels of the tight junction proteins and genes related to the p62-Keap1-Nrf2 signaling pathway in the liver and jejunum were determined. with ETEC K88, and to analyze the molecular mechanism of CB pretreatment in alleviating ETEC K88-induced oxidative damage in mice based on the p62-Keap1-Nrf2 signaling pathway and intestinal microbial community, in order to provide a basis for the rational use of CB in feed. Experimental Materials CB was isolated from the feces of healthy piglets and its identity confirmed based on colony morphology, Gram staining, and sequencing of its 16S rDNA. ETEC K88 was obtained from the Laboratory of College of Animal Science and Veterinary Medicine, TianjinAgriculturalUniversity.LiveETECK88wasinoculatedinto Luria–Bertani liquid medium and incubated at 37°C for 24 h. Live CB was inoculated into Reinforced Clostridial Medium, a liquid medium, and incubated at 37°C for 48 h. Bacteria liquid: glycerol (1:1) was then stored in a refrigerator at −80°C for subsequent experiments. CBandETECK88wereenumeratedonsolidmedium before the experiment. Kunming mice were purchased from the China National Institute for Food and Drug Control. Male Kunming mice aged 9–10 weeks that were in good health and weighed 22–25 g were selected for the experiment. Mice in the CONT, H-ETEC, H-CB and H-CB+H-ETEC groups were selected for analysis of the microbial community structure and its changes, and the contents of short-chain fatty acids (SCFAs) were determined. The mouse cages were disinfected before the test, and mice were allowedtoadapttotheenvironmentfor3d.Duringtheexperiment, all mice were allowed to drink and eat freely, and the temperature and humidity were controlled within ranges of 18–22°C and 50– 60%, respectively; moreover, there was a 12 h light/dark cycle, and good ventilation was maintained. The maintenance feed for mice was purchased from Beijing Keao Xieli Feed Co, Ltd (Beijing, China). The composition of the feed ingredients: corn, soybean meal, fish power, flour, bran, NaCl, calcium hydrogen phosphate, stone powder, a variety of vitamins, a variety of trace elements, amino acids, etc. The guaranteed values for product composition analysis are shown in Table S1 (Supplementary Material). Experimental Designs Experiment 1 Establishment of ETEC disease model Forty-eight mice were randomly divided into three groups [control group (CONT), low-dose group (L-ETEC), and high- dose group (H-ETEC)], with sixteen replicates in each group. The mice in the CONT group were gavaged with 0.2 mL normal saline, while those in the L-ETEC group were gavaged with 0.2 mL 3.7 × 107 CFU/mL ETEC K88 and those in the H-ETEC group were gavaged with 0.2 mL 3.7 × 108 CFU/mL ETEC K88. After 24 h, six mice with similar body weights were randomly selected and sacrificed in each group, and their serum antioxidant indexes were detected. The optimal concentration of the ETEC disease model was then selected. Observation of Tissue Histopathology Ninety-six mice were randomly divided into 6 groups, with 16 mice in each group. Mice in the CONT group were gavaged with 0.2 mL normal saline on days 1-16; mice in the H-ETEC group Mice liver and jejunum tissues were fixed in 4% paraformaldehyde for at least 48 h at room temperature. After dehydration in the November 2021 | Volume 12 | Article 771826 Frontiers in Immunology | www.frontiersin.org 3 CB Alleviates Oxidative Damage Li et al. Li et al. extracted with TRIzol reagent (Takara Biotechnology, Dalian, China) according to the manufacturer’s instructions. Following reverse transcription of RNA into cDNA, qPCR was performed using the primers shown in Table 1. Among them, p62 and Nrf2 specificprimersweredesignedusingprimer5andthefullsequences of their genes obtained from NCBI. p62, Nrf2, Heme oxygenase-1 (HO-1) (22), GSH-Px (23), SOD1 (24), SOD2 (22), claudin 1 (25), claudin 8 (26), occludin (27), and zonula occludens-1 (ZO-1) (25) mRNA expression levels were measured using LightCycler® 480 real-time PCR and calculated based on 2-DDCt. Data are shown as ratios of abundance of target gene transcripts in the treated mice to those in the control group after normalization to Glyceraldehyde-3- phosphate dehydrogenase (GAPDH) (25). Kits for nucleic acid extraction, reverse transcription, and qRT-PCR were purchased from GeneCopoeia (Rockville, USA). different concentrations of ethanol, the tissues were transparent with xylene, embedded in paraffin wax and then sectioned. Paraffin section (thickness usually 3-5 mm) were stained with hematoxylin and eosin (H&E) for routine examination. Some main steps were described below. First, the paraffin sections were dewaxed with xylene, hydrated with different concentrations of ethanol and washed with distilled water. Second, the sections were incubated in hematoxylin and eosin solution, and rinsed with distilled water. Third, the sections were dehydrated, and ethanol was removed with xylene. Finally, the sections were sealed by neutral balsam, and observed using an ECHO Revolve Hybrid microscope. Additionally, the ECHO app was used to measure villus height (VH) and crypt depth (CD) in the jejunum tissue. The VH was measured from the villus tip to the bottom. The CD was measured from the crypt tip to the bottom. An average of twelve villi and crypts was expressed as a mean VH and CD for each mouse. Detection of Serum Oxidation Indices After the collected samples were thawed, the genomic DNA of the mice ceca was extracted by the cetyltrimethyl ammonium bromide (CTAB) method, then stored in the refrigerator at low temperature (−20°C) until further PCR amplification and sequencing. The content of malondialdehyde (MDA) in the serum was determined by the TBA colorimetric method, the content of superoxide dismutase (SOD) in the serum was determined by the xanthineoxidasemethod,andthecontentofglutathioneperoxidase (GSH-Px)inthe serum was determined byvisible light colorimetry. The MDA, SOD and GSH-Px assay kits were purchased from Nanjing Jiancheng Biology Engineering Institute (Nanjing, China). Specific testing methods referred to Sun et al. (21). The following 16S rRNA gene primers were used to amplify the 16S rRNA gene V3-V4 region of cecum microbiota: 341F: 5’- CCTAYGGGRBGCASCAG; 806R: 5’-GGACTACNNG GGTATCTAAT-3’. Following amplification, 2% agarose gel electrophoresis was used to detect the purity and concentration of the extracted genomic DNA. PCR products were then purified and recovered with a PCR extraction kit for quantitative determination (QIAGEN, Germany). Finally, the amplified PCR products were sequenced on the Illumina NovaSeq 6000 platform F, shows forward primer; R, shows reverse primer. Statistical Analysis SPSS 22.0 was used to perform one-way ANOVA of the growth performance, oxidation index, relative gene expression, and cecal short-chain fatty acids of mice in different groups, with Duncan’s and LSD method used to identify significant differences among groups. For nonparametric data, Mann-Whitney U test was performed. p gy As shown in Figures 2A–F, the liver structure was normal with orderly arranged-hepatic in the CONT, L-CB and H-CB groups. In the liver of mice in H-ETEC group, a large number of inflammatory cells gathered around the vessels (red arrows), or inflammatory cells (blue arrows) dispersed in the vessels and hepatic sinuses, and the hepatic sinusoidal space was slightly enlarged. In the L-CB+H-ETEC and H-CB+H-ETEC groups, inflammatory cells diffused in the hepatic sinus space, and there was no large accumulation of inflammatory cells. Taken together, these results indicated that CB pretreatment can alleviate liver damage caused by ETEC K88 challenge. Flash V1.2.7 (28) was used to splice the sample reads after the primer and barcode sequences to give sequences, which were then filtered and analyzed using QIIME V1.9.1. Next, Uparse v7.0.1001 (29) was used to cluster the sequences, with those having more than 97% similarity being considered the same operational taxonomic unit (OTU). Each OTU sequence was subsequently extracted and annotated using Mothur and the SSUrRNA database (30) of SILVA132 (31). As shown in Figures 2G–L, jejunal villi were arranged neatly in the CONT, L-CB and H-CB groups, while in the H-ETEC group, the jejunal villi became shorter, the number of inflammatory cells in villi increased, intestinal epithelial cells separated from lamina propria, and even fell off in intestinal cavity. The degree of separation and abscission of epithelial cells from lamina propria were alleviated to a certain extent in L-CB+ H-ETEC and H-CB+H-ETEC groups. Taken together, these results indicated that CB pretreatment can alleviate ETEC K88-induced jejunum tissue lesions. QIIME (version 1.9.1) was used to conduct a-diversity analysis (including ACE, Shannon, Coverage, Chao1) for OTUs with similarity levels greater than 97%. R (version 2.15.3) was then used to make species composition histograms and linear discriminant analysis (LDA) distribution histograms based on the OTUs abundance information to visually characterize the similarities and differences in bacterial community composition. RESULTS by Beijing Novogene Biology Information Technology Co., Ltd (Beijing, China). All raw data have been deposited in NCBI BioProject (accession number: PRJNA765776). Optimization of ETEC K88 and CB Doses As shown in Figures 1A–C, after ETEC K88 challenge, the MDA level in the serum was significantly higher than that of the CONT group (all p < 0.001), especially in the H-ETEC group. The SOD and GSH-Px levels in the serum in the H-ETEC group were significantly lower than those in the CONT (all p < 0.001) and L- ETEC groups (all p < 0.001). Based on the obtained results, 3.7×108 CFU/mL was selected as the optimal concentration for the ETEC K88 pathogenic model. Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) After the frozen liver and jejunum tissues of mice were homogenized in liquid nitrogen, the RNA in the tissues was TABLE 1 | Primer sequences information. Gene names Primer sequence/(5’!3’) Product length/bp Annealing temperature/°C GenBank accession number p62 F: CAACTGTTCAGGAGGAGACGA R: CTGGTGGCAGATGTGGGTA 179 62 XM_036156414.1 Nrf2 F: CAGTGCTCCTATGCGTGAA R: GCGGCTTGAATGTTTGTC 109 56 NM_010902.4 HO-1 F: CAAGGAGGTACACATCCAAGCC R: TACAAGGAAGCCATCACCAGCT 102 56 NM_010442.2 GSH-Px F: GAAGTGCGAAGTGAATGG R: TGTCGATGGTACGAAAGC 224 56 X03920.1 SOD1 F: AACCAGTTGTGTTGTGAGGAC R: CCACCATGTTTCTTAGAGTGAGG 139 56 NM_011434.2 SOD2 F: ACGCCACCGAGGAGAAGTACC R: CGCTTGATAGCCTCCAGCAACTC 181 62 NM_013671.3 Claudin 1 F: GAGTCTCCGGTGCATCATTT R: CAGCTTGCTAGGGAACTTGG 143 56 NM_001379248.1 Claudin 8 F: GTGCTGCGTCCGTCTTGGCT R: TCGTCCCCCGTGCATCTGGT 79 62 NM_018778.3 Occludin F: CCTTCTGCTTCATCGCTTCCTTA R: CGTCGGGTTCACTCCCATTAT 164 56 NM_001360538.1 ZO-1 F: GGGAGGGTCAAATGAAGACA R: GGCATTCCTGCTGGTTACAT 145 56 XM_036152895.1 GAPDH F: GCACAGTCAAGGCCGAGAAT R: GCCTTCTCCATGGTGGTGAA 151 56/62 XM_036165840.1 F, shows forward primer; R, shows reverse primer. TABLE 1 | Primer sequences information. November 2021 | Volume 12 | Article 771826 Frontiers in Immunology | www.frontiersin.org CB Alleviates Oxidative Damage Li et al. Detection of Short-Chain Fatty Acids (SCFAs) After the collected samples were thawed, about 0.5 g of the cecal content was put into 1.5 mL centrifuge tubes. Next, 1.25 mL of ultrapure water was added, after which the samples were vortexed for 3–5 min. Samples were subsequently centrifuged at 5,000 rpm for 10 min, after which 1.5 mL of the supernatant was collected and placed in a centrifuge. To the tubes, 0.2 mL of 25% metaphosphoric acid solution was added at a ratio of 5: 1. Samples were subsequently shaken well, placed in an ice-water bath for 30 min, then centrifuged for 10 min at 10,000 rpm at 4°C for 10 min. The supernatant was then collected, after which the contents of butyrate, acetate, propionate and total SCFAs in the cecum contents were determined by gas chromatography (Agilent 7890B). Gas chromatographic conditions were described below. The separation was performed on a DB-FFAP (30 m × 0.25 mm × 0.25 mm) column. The injector temperatures were 220°C, and the carrier gas (nitrogen) was injected at a rate of 1.0 mL/min. The detector temperatures were 250°C. The initial temperature was 100°C and the temperature was risen at 30°C per minute for 6 min. p g As shown in Figures 1D, E, the average body weight of mice in the H-CB group was significantly higher than that of mice in the CONT (day 7 p = 0.038, day 14 p = 0.003) and L-CB groups (day 7 p = 0.012, day 14 p = 0.013) on day 7 and day 14. On days 0–7, the average daily weight gain of mice in the L-CB and H-CB groups was significantly higher than that in the CONT group (p = 0.017 and p < 0.001 respectively), and that the effects in the H-CB group were more obvious (p < 0.001). On days 7–14, the average daily gain of mice in the CONT group was significantly lower than that in the L-CB and H-CB groups (all p < 0.001). But based on the above body weight results, we are still not sure which concentration of CB has a better therapeutic effect on oxidative damage in mice. Therefore, 4.4 × 105 CFU/mL and 4.4×106 CFU/mL CB were used for subsequent experiments. Frontiers in Immunology | www.frontiersin.org Statistical Analysis As shown in Figure 3 and Table S2 (Supplementary material), when compared with the CONT group, ETEC K88 treatment alone could significantly increase crypt depth, reduce the jejunal villus height and VH/CD ratio (p = 0.031, p < 0.001 and p < 0.001, respectively). In addition, the jejunal villus height (p = 0.043 and p < 0.001, respectively) and VH/CD ratio (p = 0.043 and p < 0.001, respectively) showed significant changes Spearman’s correlation values of species, oxidative stress indices, and SCFA contents were calculated using the psych package in R, and their significance was tested to identify mutual relationships between the oxidative stress index, SCFA contents, and microbial species richness (alpha diversity). The top 20 species based on abundance at the genus level were chosen for correlation analysis. November 2021 | Volume 12 | Article 771826 Frontiers in Immunology | www.frontiersin.org 5 Li et al. CB Alleviates Oxidative Damage A B D E C FIGURE 1 | Effects of different levels of ETEC on (A) MDA, (B) SOD, and (C) GSH-Px in the serum of mice (n = 6 mice per group). Effects of different levels of CB on (D) body weight and (E) average daily gain of mice (n = 16 mice per group). Values shown are the means ± SEM. Different small letters indicate significant differences (p < 0.05). A B C D E E D FIGURE 1 | Effects of different levels of ETEC on (A) MDA, (B) SOD, and (C) GSH-Px in the serum of mice (n = 6 mice per group). Effects of different levels of CB on (D) body weight and (E) average daily gain of mice (n = 16 mice per group). Values shown are the means ± SEM. Different small letters indicate significant differences (p < 0.05). after treatment with CB alone. When compared with the H- ETEC group, co-treatment with CB and ETEC K88 dramatically decreased crypt depth (p = 0.047 and p < 0.001, respectively) and significantly increased the villus height and VH/CD (all p < 0.001). FIGURE 2 | Effects of CB and/or ETEC K88 on observation of tissular morphology. (A–F) hematoxylin-eosin staining in the liver of mice. (A) CONT, (B) H-ETEC, (C) L-CB, (D) H-CB, (E) L-CB+H-ETEC, (F) H-CB+H-ETEC; (G–L) hematoxylin-eosin staining in the jejunum of mice. (G) CONT, (H) H-ETEC, (I) L-CB, (J) H-CB, (K) L-CB+H-ETEC, (L) H-CB+H-ETEC. Bar = 100 mm. CB Helps to Maintains the Soundness of Barrier Function in Mice As shown in Figures 4A–D, following treatment with CB alone, the mRNA expression level of claudin 1 in the liver increased significantly (all p < 0.001). Additionally, the mRNA expression levels of occludin in the liver changed significantly after treatment with 4.4 × 106 CFU/mL CB (p < 0.001). Following challenge with 3.7 × 108 CFU/mL ETEC K88, the mRNA expression levels of claudin 1 and occludin in the liver did not change significantly (p = 0.815 and p = 0.210, respectively), while the mRNA expression levels of claudin 8 and ZO-1 in the liver were significantly reduced (all p < 0.001). CB pretreatment reversed the downregulation of claudin 8 and ZO-1 mRNA expression induced by ETEC K88 in a dose-dependent manner, further promoted the expression of claudin 1 and occludin at the transcriptional level in the liver. As shown in Figures 4E–H, when compared with the CONT group, the mRNA expression levels of claudin 1 in the jejunum did not change significantly (p = 0.939), the mRNA expression level of claudin 8 in the jejunum was significantly increased (p = 0.008), and the mRNA expression level of ZO-1 and occludin in the jejunum was significantly decreased (p = 0.045 and p = 0.036, respectively) in the H-ETEC group. Additionally, in the L-CB and H-CB groups, the mRNA expression level of claudin 1, claudin 8, occludin, and ZO-1 in the jejunum increased significantly (all p < 0.001). When compared with the H-ETEC group, the mRNA expression levels of claudin 8 (p = 0.002 and FIGURE 2 | Effects of CB and/or ETEC K88 on observation of tissular morphology. (A–F) hematoxylin-eosin staining in the liver of mice. (A) CONT, (B) H-ETEC, (C) L-CB, (D) H-CB, (E) L-CB+H-ETEC, (F) H-CB+H-ETEC; (G–L) hematoxylin-eosin staining in the jejunum of mice. (G) CONT, (H) H-ETEC, (I) L-CB, (J) H-CB, (K) L-CB+H-ETEC, (L) H-CB+H-ETEC. Bar = 100 mm. November 2021 | Volume 12 | Article 771826 Frontiers in Immunology | www.frontiersin.org 6 Li et al. Li et al. CB Alleviates Oxidative Damage A B C FIGURE 3 | Effect of CB and/or ETEC K88 on the jejunal form of mice. (A) villus height, (B) crypt depth, (C) VH/CD (n = 6 mice per group, n =12 villi and crypts per mouse). Values shown are the means ± SEM. Different small letters indicate significant differences (p < 0.05). CB Helps to Protect Mice Against ETEC K88-Induced Oxidative Damage Through Regulation of the p62-Keap1-Nrf2 Signaling Pathway PCR amplification and sequencing were performed on the 16S rDNA V3-V4 region of the genomic DNA of the cecal contents. After obtaining the raw tags of 12 samples and performing splicing, quality control, and filtering to remove the chimera, a total of 47,918 ± 2,940 effective tags, 19,785,811 ± 1,224,633 bp bases, and a 413 bp AvgLen (average length of effective tags) were obtained. Based on the minimum number of sample sequences and clustering the OTUs at 97% similarity, a total of 1296 OTUs were obtained, including 1 kingdom, 13 phyla, 21 classes, 43 orders, 72 families, 158 genera, and 141 species. As shown in Figures 5A–C, after treatment with CB alone, the MDA level in the serum did not differ significantly from that of the CONT group (p = 0.960 and p = 0.468, respectively), while the SOD and GSH-Px levels had increased significantly (all p < 0.001). Additionally, the MDA level in the H-ETEC group was significantly increased relative to the CONT group (p < 0.001), while the SOD and GSH-Px levels were significantly decreased (all p < 0.001). However, CB pretreatment significantly reduced MDA levels and increased SOD and GSH-Px levels in the serum in a dose-dependent manner in ETEC K88-infected mice, and 4.4 × 106 CFU/mL CB significantly interfered with ETEC K88- induced oxidative damage in mice. g p As shown in Figure 6A, the ACE and Chao1 indexes did not differ significantly among the four groups (p = 0.887), indicating that there was no significant difference in the abundance of cecal bacteria among treatment groups. Additionally, the coverage was around 0.99, indicating that the sequencing results fully reflected the actual situation of the microbiota. The Shannon’s index of the H-ETEC, H-CB, and H-CB+H-ETEC groups was lower than that of the CONT group, and there was a significant difference between the H-CB+H-ETEC group and CONT group (p = 0.021), indicating that the diversity of the bacterial community tended to decrease in ceca treated with ETEC K88 and CB. At the phylum level, the top 10 species in terms of relative abundance were selected. The mean value of abundance was then used to calculate the proportion of each bacterial group in the samples of the four groups, and relative abundance histograms of the species were made (Figure 6B). CB Helps to Protect Mice Against ETEC K88-Induced Oxidative Damage Through Regulation of the p62-Keap1-Nrf2 Signaling Pathway The results showed that Firmicutes and Bacteroidetes were the dominant phyla in all groups, and that there were no significant differences in relative abundance (p = 0.648 and p = 0.646, respectively). However, the Firmicutes/ Bacteroidetes ratio in the H-CB group was significantly higher than that in the other three groups (p = 0.003, p = 0.011 and p = 0.010, respectively). To determine the specific cecal microbiota in the different treatment groups, the LDA score was set at 4 at the phylum-to-species classification level, LEfSe multi-level species difference discriminant analysis was performed, and an LDA distribution histogram was made (Figures 7A–D). Mice in the H-ETEC group showed lower abundance of Bacillales, Staphylococcaceae, Staphylococcus, and Staphylococcus_lentus than in the H-CB group (Figure 7A), whereas unidentified_Clostridiales, unidentified_Clostridiales, and Clostridium_disporicum in the H-ETEC group exhibited higher abundance than in the CONT group (Figure 7B). Additionally, mice treated with 4.4 × 106 CFU/mL CB showed As shown in Figures 5D–I, the mRNA expression level of SOD2 in the liver was significantly reduced in the H-ETEC group compared to the CONT group (p = 0.012). In the L-CB and H- CB group, the mRNA expression levels of Nrf2 (p = 0.001 and p < 0.001, respectively), GSH-Px (p = 0.005 and p = 0.001, respectively), SOD1 (p = 0.014 and p = 0.018, respectively), and SOD2 (p = 0.018 and p < 0.001, respectively) in the liver were significantly increased compared to the CONT group. In addition, compared to the CONT group, the mRNA expression levels of p62 and HO-1 in the liver were significantly increased in the H-CB group (p = 0.008 and p = 0.007, respectively). When compared with the H-ETEC group, the mRNA expression levels of p62 (all p < 0.001), Nrf2 (all p < 0.001), HO-1 (p = 0.024 and p < 0.001, respectively), GSH-Px (all p < 0.001), SOD1 (all p < 0.001), and SOD2 (p = 0.033 and p < 0.001, respectively) in the liver were significantly increased in the L-CB+H-ETEC and H- CB+H-ETEC groups in a dose-dependent fashion. As shown in Figures 5J–O, the mRNA expression levels of p62, Nrf2, HO-1, GSH-Px, SOD1, and SOD2 in the jejunum were significantly decreased in the H-ETEC group when compared with the CONT group (p = 0.009, p = 0.002, p = 0.012, p = 0.043, p = 0.018 and p = 0.035, respectively). CB Helps to Maintains the Soundness of Barrier Function in Mice Taken together, these results indicated that 4.4 × 106 CFU/mL CB pretreatment can reverse the downregulation expression of tight junction proteins (claudin 1, claudin 8, occludin, and ZO-1) at the transcriptional level in the liver and jejunum. they did show an upward trend. Furthermore, co-treatment with 4.4 × 106 CFU/mL CB and ETEC K88 significantly increased the p62, Nrf2, HO-1, GSH-Px, SOD1, and SOD2 mRNA expression levels in the jejunum when compared with the H-ETEC group (all p < 0.001). Taken together, these results indicate that CB pretreatment can increase the mRNA expression of p62, Nrf2, HO-1, GSH-Px, SOD1, and SOD2 in the liver and jejunum of ETEC K88-infected mice in a dose-dependent manner. CB Helps to Maintains the Soundness of Barrier Function in Mice FIGURE 3 | Effect of CB and/or ETEC K88 on the jejunal form of mice. (A) villus height, (B) crypt depth, (C) VH/CD (n = 6 mice per group, n =12 villi and crypts per mouse). Values shown are the means ± SEM. Different small letters indicate significant differences (p < 0.05). A B D E F G H C FIGURE 4 | Effects of CB and/or ETEC K88 on the mRNA expression levels of tight junction proteins. (A–D) The mRNA expression levels of claudin 1, claudin 8, occludin, and ZO-1 in the livers of mice were measured by qRT-PCR (n = 6 mice per group). (E–H) The expression of claudin 1, claudin 8, occludin, and ZO-1 in the jejunum of mice was measured by qRT-PCR (n = 6 mice per group). Data are shown as the ratios of abundance of target gene transcripts in treated mice to those in control mice after normalization to GAPDH. Values shown are the means ± SEM. Different small letters indicate significant differences (p < 0.05). A B D D C E E F H G H H G FIGURE 4 | Effects of CB and/or ETEC K88 on the mRNA expression levels of tight junction proteins. (A–D) The mRNA expression levels of claudin 1, claudin 8, occludin, and ZO-1 in the livers of mice were measured by qRT-PCR (n = 6 mice per group). (E–H) The expression of claudin 1, claudin 8, occludin, and ZO-1 in the jejunum of mice was measured by qRT-PCR (n = 6 mice per group). Data are shown as the ratios of abundance of target gene transcripts in treated mice to those in control mice after normalization to GAPDH. Values shown are the means ± SEM. Different small letters indicate significant differences (p < 0.05). November 2021 | Volume 12 | Article 771826 Frontiers in Immunology | www.frontiersin.org 7 CB Alleviates Oxidative Damage Li et al. Li et al. p< 0.001, respectively), occludin (p = 0.033 and p < 0.001, respectively), and ZO-1 (p = 0.015 and p < 0.001, respectively) in the jejunum were significantly increased in the L-CB+H- ETEC and H-CB+H-ETEC groups. Additionally, the mRNA expression level of claudin 1 in the jejunum in the H-CB+H- ETEC group was significantly higher than that in H-ETEC group (p < 0.001). CB Helps to Protect Mice Against ETEC K88-Induced Oxidative Damage Through Regulation of the p62-Keap1-Nrf2 Signaling Pathway When compared with the H-ETEC group, co-treatment with 4.4 × 105 CFU/mL CB and ETEC K88 significantly increased the p62, Nrf2 and GSH-Px mRNA expression levels in the jejunum (p = 0.048, p = 0.020, and p = 0.035, respectively). Additionally, although HO-1, SOD1, and SOD2 mRNA expression levels in the jejunum did not change significantly (p = 0.912, p = 0.068, and p = 0.867, respectively), November 2021 | Volume 12 | Article 771826 Frontiers in Immunology | www.frontiersin.org 8 Li et al. CB Alleviates Oxidative Damage A B D E F G I H J K L M N C O FIGURE 5 | Effects of CB and/or ETEC K88 on the levels of MDA, SOD, GSH-Px, p62, Nrf2, HO-1, GSH-Px, SOD1, and SOD2 in mice. (A–C) The levels of MDA, SOD, and GSH-Px in the serum of mice were measured (n = 6 mice per group). (D–I) The mRNA expression levels of p62, Nrf2, HO-1, GSH-Px, SOD1, and SOD2 in the livers of mice were measured by qRT-PCR (n = 6 mice per group). (J–O) The mRNA expression levels of p62, Nrf2, HO-1, GSH-Px, SOD1, and SOD2 in the livers of mice were measured by qRT-PCR (n = 6 mice per group). Data are shown as ratios of abundance of target gene transcripts in the treated mice to those in the control mice after normalization to GAPDH. Values shown are the means ± SEM. Different small letters indicate significant differences (p < 0.05). D E F G I H J K L J M M N O O FIGURE 5 | Effects of CB and/or ETEC K88 on the levels of MDA, SOD, GSH-Px, p62, Nrf2, HO-1, GSH-Px, SOD1, and SOD2 in mice. (A–C) The levels of MDA, SOD, and GSH-Px in the serum of mice were measured (n = 6 mice per group). (D–I) The mRNA expression levels of p62, Nrf2, HO-1, GSH-Px, SOD1, and SOD2 in the livers of mice were measured by qRT-PCR (n = 6 mice per group). (J–O) The mRNA expression levels of p62, Nrf2, HO-1, GSH-Px, SOD1, and SOD2 in the livers of mice were measured by qRT-PCR (n = 6 mice per group). Data are shown as ratios of abundance of target gene transcripts in the treated mice to those in the control mice after normalization to GAPDH. Values shown are the means ± SEM. Frontiers in Immunology | www.frontiersin.org CB Helps to Protect Mice Against ETEC K88-Induced Oxidative Damage Through Regulation of the p62-Keap1-Nrf2 Signaling Pathway Different small letters indicate significant differences (p < 0.05). higher levels of Bacilli, Lactobacillales, Lactobacillaceae, Lactobacillus, Bacillales, Staphylococcaceae, and Staphylococcus than in the CONT and H-CB+H-ETEC groups, whereas unidentified_Lachnospiraceae, Bacteroidetes, Bacteroidia, and Bacteroidales in the H-CB group showed lower abundance than the CONT group (Figures 7C, D). 0.369 and p = 0.328, respectively), propionate (p = 0.124 and P = 0.192, respectively), butyrate (p = 0.374 and P = 0.478, respectively), and total SCFAs (p = 0.082 and p = 0.209, respectively) in the H-CB+H-ETEC group were not significantly different compared with those in the CONT and H-ETEC groups, but the concentrations tended to increase compared with the H-ETEC group. These findings indicated that CB pretreatment can increase the concentrations of SCFAs in the cecum of ETEC K88-infected mice to a certain extent. As shown in Figure 8, the concentrations of propionate (p = 0.014) and total SCFAs (p = 0.010) in the H-ETEC group were significantly lower than those in the CONT group. When compared with the CONT group, there were no significant differences in the concentrations of acetate (p = 0.211), propionate (p = 0.602), butyrate (p = 0.107), and total SCFAs (p = 0.238) in the H-CB group. The concentrations of acetate (p = Spearman’s correlation was used to analyze the oxidation indicators (MDA, SOD, GSH-Px), SCFAs, and microbiota to evaluate the correlation between ETEC K88-induced oxidative stress and changes in the intestinal microbiota and their November 2021 | Volume 12 | Article 771826 Frontiers in Immunology | www.frontiersin.org 9 Li et al. CB Alleviates Oxidative Damage A B A B A B FIGURE 6 | Effects of CB and/or ETEC K88 on the cecal microbial community structure. (A) Alpha diversity of cecal microbiota in mice (n = 3 mice per group). (B) Relative abundance of cecal microbiota of mice in different groups at the phylum level (n = 3 mice per group). Values shown are the means ± SEM. Different small letters indicate significant differences (p < 0.05). BBB AA FIGURE 6 | Effects of CB and/or ETEC K88 on the cecal microbial community structure. (A) Alpha diversity of cecal microbiota in mice (n = 3 mice per group). (B) Relative abundance of cecal microbiota of mice in different groups at the phylum level (n = 3 mice per group). Values shown are the means ± SEM. Different small letters indicate significant differences (p < 0.05). CB Helps to Protect Mice Against ETEC K88-Induced Oxidative Damage Through Regulation of the p62-Keap1-Nrf2 Signaling Pathway A B D C FIGURE 7 | Identification of specific microbial communities under CB and/or ETEC K88. Different bacteria communities from the phylum to species level were evaluated by linear discriminant analysis coupled with effect size (LEfSe). (A) Among four different groups, (B) between CONT and H-ETEC groups, (C) between CONT and H-CB groups, and (D) among CONT, H-CB and H-CB+H-ETEC groups (n = 3 mice per group). A A B A B D C C D C FIGURE 7 | Identification of specific microbial communities under CB and/or ETEC K88. Different bacteria communities from the phylum to species level were evaluated by linear discriminant analysis coupled with effect size (LEfSe). (A) Among four different groups, (B) between CONT and H-ETEC groups, (C) between CONT and H-CB groups, and (D) among CONT, H-CB and H-CB+H-ETEC groups (n = 3 mice per group). metabolites (Figures 9A, B). As shown in Figure 9A, Roseburia was significantly positively correlated with acetate and propionate (p = 0.027 and p = 0.048, respectively), while Lachnoclostridium was significantly positively correlated with SCFA contents (p = 0.032, p < 0.001, p = 0.032 and p = 0.002, respectively). Terrisporobacter was found to have a significant negative correlation with propionate and total short-chain fatty acids (p = 0.011 and p = 0.042, respectively). As shown in Figure 9B, Lachnoclostridium had a significant negative correlation with MDA (p = 0.010) and a significant positive correlation with SOD (p = 0.006). In addition, Bacteroides was significantly negatively correlated with GSH-Px and SOD (p < 0.001 and p = 0.011, respectively), Lactobacillus was positively correlated with SOD (p = 0.033), and Akkermansia was positively correlated with GSH-Px (p = 0.033). It should be noted that Lachnoclostridium, Lactobacillus, and Roseburia all belong to Lachnospiraceae. Taken together, these results indicate that a positive effect of CB pretreatment on ETEC K88-infected mice may be achieved by increasing the abundance of Lactobacillus and the contents of SCFAs. DISCUSSION In the animal body, when the oxidative and antioxidant balance is disturbed by a pathogen infection, oxidative stress will occur (32). The integrity of tissue morphology and barrier function is one of the most important indicators used to evaluate the health November 2021 | Volume 12 | Article 771826 Frontiers in Immunology | www.frontiersin.org 10 Li et al. CB Alleviates Oxidative Damage A B D C FIGURE 8 | Effects of CB and/or ETEC K88 on (A) acetate, (B) propionate, (C) butyrate and (D) total short-chain fatty acids in the cecum of mice (n = 3 mice per group). Values shown are the means ± SEM. Different small letters indicate significant differences (p < 0.05). A B B C D C FIGURE 8 | Effects of CB and/or ETEC K88 on (A) acetate, (B) propionate, (C) butyrate and (D) total short-chain fatty acids in the cecum of mice (n = 3 mice per group). Values shown are the means ± SEM. Different small letters indicate significant differences (p < 0.05). A B FIGURE 9 | Correlation among cecal microbiota, cecal SCFAs and oxidative stress indexes. (A) Spearman’s correlation analyses between the cecal SCFAs and microbiota at the genus level (n = 3 mice per group). (B) Spearman’s correlation analyses between the cecal microbiota and oxidative stress indexes at the genus level (n = 3 mice per group). * represents the specific genus whose abundance were significantly correlated with cecal SCFAs or oxidative stress indexes. * 0.01 < p ≤0.05, ** 0.001 < p ≤0.01. B A B A FIGURE 9 | Correlation among cecal microbiota, cecal SCFAs and oxidative stress indexes. (A) Spearman’s correlation analyses between the cecal SCFAs and microbiota at the genus level (n = 3 mice per group). (B) Spearman’s correlation analyses between the cecal microbiota and oxidative stress indexes at the genus level (n = 3 mice per group). * represents the specific genus whose abundance were significantly correlated with cecal SCFAs or oxidative stress indexes. * 0.01 < p ≤0.05, ** 0.001 < p ≤0.01. of animals. Additionally, villus height and crypt depth are key factors that determine intestinal absorption and digestion of nutrients, and their ratio reflects intestinal function (33). When the intestinal villus height becomes shorter, the absorption area of the intestine decreases, which affects nutrient absorption (34). DISCUSSION This study showed that ETEC K88 can reduce villus height and VH/CD ratio, increase crypt depth, which may affect digestion and absorption in mice. Oxidative stress has been reported to be important to impairment of barrier function. Specifically, it can change the structure of the occludin-ZO-1 complex by stimulating tyrosine phosphorylation, destroy tight junctions, and destroy barrier function (35). ETEC K88 was previously November 2021 | Volume 12 | Article 771826 Frontiers in Immunology | www.frontiersin.org 11 CB Alleviates Oxidative Damage Li et al. body and can regulate the expression of antioxidant enzyme genes (42). Therefore, we determined the expression of p62, Nrf2, HO-1, GSH-Px and SODs genes at the transcriptional level in mouse liver and jejunum. The results suggested that after treatment with ETEC K88 alone, the mRNA expression of genes related to the p62-Keap1-Nrf2 signaling pathway were all significantly lower in jejunum, while only SOD2 mRNA expression was significantly lower in liver, indicating that jejunum is more susceptible to ETEC K88 than liver. Moreover, CB pretreatment increased the expression of p62, Nrf2, HO-1, GSH-Px, and SODs genes in the liver and jejunum of ETEC K88- infected mice. The upregulation of antioxidant enzyme genes is an adaptation to oxidative stress. In addition, it has been confirmed in our previous in vitro study that CB could activate the Nrf2/ARE signaling pathway to alleviate ETEC K88-induced oxidative damage in porcine intestinal epithelial cells (43). Therefore, it is speculated that the role of CB in alleviating oxidative damage in ETEC K88-infected mice may be related to the activation of the p62-Keap1-Nrf2 signaling pathway, and the effect in the H-CB+ H-ETEC group was more obvious than that in the L-CB+H- ETEC group. FIGURE 10 | Diagram outlining the mechanism of CB on alleviating ETEC K88-induced oxidative damage. g p The intestinal microbiota constitutes a natural barrier against invasion by exogenous pathogens, and plays an important role in host metabolism, immunity, and evolution (44). Therefore, we used 16S rDNA amplicon sequencing to detect changes in mouse cecum microbiota. Firmicutes and Bacteroidetes dominate animal intestines, and their abundance ratio is often used as a sign of intestinal microbial disorders (45). This study found that at the phylum level, the dominant bacteria in the ceca of mice were Firmicutes and Bacteroidetes, and their ratio was significantly higher in the H-CB group, indicating CB treatment could maintain the balance of intestinal microbiota. DISCUSSION In addition, the abundance of Clostridium disporicum in ETEC K88-challenged mice was significantly higher than that in the CONT group, Staphylococcus_lentus and Lactobacillus were significantly clustered in the H-CB group in this study. Clostridium_disporicum is a saccharolytic species within Firmicutes that exists in the ceca of mice (46) and is related to the degradation of complex organic matter (47), but its actual effects in the intestine are unclear. However, studies have shown that Clostridium_disporicum was found in the intestinal microbiota of patients with gastrointestinal dysfunction (48), so it is speculated that this organism may play a negative role in the intestine. However, Lactobacillus are gram-positive bacteria that can promote the fermentation of carbohydrates into lactic acid. Moreover, the combination of Lactobacillus reuteri CCM8617 and flaxseed can increase the concentration of SCFAs in the intestines of mice, maintain the integrity of the mucosa, promote the growth of intestinal epithelial cells, have a biological antagonistic effect on the pathogenic bacteria E.coli O149:F4, and promote intestinal health (49). It is worth noting that Staphylococcus lentus, which was significantly enriched in the cecum after treatment with CB, is an animal pathogen (50). Moreover, it has been reported that CB may carry virulence genes capable of producing botulinum toxin or clostridium toxin, which are pathogenic and interfere with the balance of FIGURE 10 | Diagram outlining the mechanism of CB on alleviating ETEC K88-induced oxidative damage. shown to induce impairment of barrier function of pig intestinal epithelial cells by reducing the expression of ZO-1 and occludin (36), and these effects were confirmed in mice in the present study. This study also revealed that CB pretreatment can increase the villus height and VH/CD ratio in the jejunum of ETEC K88- infected mice, promote intestinal development, and maintain the integrity of intestinal villus structure. This pretreatment also improves expression of the tight junction protein in the liver and jejunum at the transcriptional level, maintains tissue barrier function, and alleviates oxidative damage caused by ETEC K88 in mice, which is consistent with the results reported by Chen et al. (37). Therefore, determining how CB pretreatment can improve ETEC K88-induced oxidative damage in mice was the focus of this study. MDA, SOD, and GSH are all important markers reflecting the degree of oxidative stress. Frontiers in Immunology | www.frontiersin.org DISCUSSION Among these, SOD and GSH are members of the body’s antioxidant system that can effectively decompose peroxides and lipid peroxides; therefore, the levels of SOD and GSH can reflect the body’s ability to scavenge oxygen free radicals (38, 39). GSH-Px can utilizes reduced GSH to convert H2O2 to water, effectively maintaining cell stability and protecting cell structure (40). MDA is a lipid metabolite that can directly reflect the intensity and rate of lipid peroxidation in the body and indirectly reflect the extent of tissue impairment by free radicals (41). This study revealed that CB pretreatment can reverse the upregulation of MDA levels and the downregulation of SOD and GSH-Px levels in the serum by ETEC K88, and alleviate oxidative damage. The p62-Keap1-Nrf2 signaling pathway is the most important endogenous antioxidant signaling pathway in the November 2021 | Volume 12 | Article 771826 Frontiers in Immunology | www.frontiersin.org 12 CB Alleviates Oxidative Damage Li et al. intestinal microbiota (51). Thus, the probiotic effects of CB and factors that trigger the expression of pathogenic factors require further investigation. Figure 10. CB can up-regulate the mRNA expression of genes related to the p62-Keap1-Nrf2 signaling pathway, promote the expression of tight junction proteins at the transcriptional level, and alleviate ETEC K88-induced oxidative damage. Additionally, it can also promote the proliferation of (Lactobacillus), compete with pathogenic bacteria for colonization sites, produce SCFAs, maintain body barrier function, and alleviate ETEC K88-induced oxidative damage. However, this study did not knock out the Nrf2 gene to further verify the role of the p62-Keap1-Nrf2 signaling pathway in the mitigation of oxidative damage by CB, which remains to be further investigated. The metabolites of gut microbiota, which are the result of interactions between the host and the microbiota, play key roles in maintenance of the integrity of the mucosal structure and tissue repair and can indirectly reflect the health of the body (14). SCFAs are derived from microbial fermented carbohydrates and play key roles in infection by pathogens (52). Therefore, this study determined the levels of butyrate, acetate, propionate, and total SCFAs in the cecum contents. It was found that ETEC K88 decreased the levels of SCFAs in the cecum contents, while CB pretreatment increased the levels of SCFAs to some extent. DISCUSSION Among SCFAs, butyrate can enhance intestinal barrier function by regulating endogenous host defense peptides and promote the body to clear ETEC O157:H7 (53, 54), acetate can impair metabolic function of ETEC K88, inhibit the accumulation of toxic homocysteine, and alleviate oxidative damage (9), and propionate can inhibit the growth and reproduction of Salmonella typhimurium by reducing pH (55). SCFAs can be quickly absorbed by the small intestine, after which they act as substrates to participate in energy production, maintain intestinal morphology and function, improve inflammation, and relieve oxidative stress (56, 57). Therefore, we hypothesized that CB alleviation of ETEC K88-induced oxidative damage in mice might be achieved by increasing the concentrations of SCFAs. ACKNOWLEDGMENTS The authors thank members of their laboratory for helpful and constructive suggestions. SUPPLEMENTARY MATERIAL In this study, ETEC K88 was used as the disease-causing model for in vivo tests. The results revealed that the alleviation of oxidative damage by CB was closely related to the p62-Keap1- Nrf2 signaling pathway and intestinal microbial community structure via the potential mechanism of action shown in The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fimmu.2021.771826/ full#supplementary-material DATA AVAILABILITY STATEMENT The original contributions presented in the study are publicly available. This data can be found here: https://www.ncbi.nlm.nih. gov/bioproject/, PRJNA765776. ETHICS STATEMENT The animal study was reviewed and approved by Tianjin Agricultural University. The animal study was reviewed and approved by Tianjin Agricultural University. FUNDING This project was financially supported by the Tianjin Natural Science Foundation [20JCZDJC00190] and the Tianjin “131” Innovative Talents Team [20180338]. AUTHOR CONTRIBUTIONS JQ, HL, and ZS designed the experiments. ZS, XL, YQ, and KW performed the experiments. ZS analyzed the experimental data. JQ and HL wrote this paper. All authors contributed to manuscript revision, read, and approved the submitted version. To better understand the relationship between intestinal microbiota and their metabolites and oxidative stress, this study used Spearman’s correlation analysis to determine if there was a close relationship between Lachnospiraceae (including Lachnoclostridium, Roseburia, and Lactobacillus), Terrisporobacter, Akkermansia, Bacteroides, and SCFAs content and oxidative stress indicators. It should be noted that Lachnospiraceae are producers of SCFAs (58). The results revealed that Terrisporobacter is positively correlated with oxidative stress, which is consistent with the results of previous studies (59). Moreover, Akkermansia is a Verrucomicrobia that can promote intestinal health (60). In this study, one important finding was that the abundance of Lactobacillus was significantly and positively correlated with SOD, suggesting that the CB pretreatment may have alleviated ETEC K88-induced oxidative damage by increasing the abundance of Lactobacillus. 4. Devriendt B, Stuyven E, Verdonck F, Goddeeris BM, Cox E. Enterotoxigenic Escherichia Coli (K88) Induce Proinflammatory Responses in Porcine Intestinal Epithelial Cells. Dev Comp Immunol (2010) 34(11):1175–82. doi: 10.1016/j.dci.2010.06.009 1. Kohen R, Nyska A. Oxidation of Biological Systems: Oxidative Stress Phenomena, Antioxidants, Redox Reactions, and Methods for Their Quantification. Toxicol Pathol (2002) 30:620–50. doi: 10.1080/01926230290166724 2. Muralidharan S, Mandrekar P. Cellular Stress Response and Innate Immune Signaling: Integrating Pathways in Host Defense and Inflammation. J Leukoc Biol (2013) 94(6):1167–84. doi: 10.1189/jlb.0313153 REFERENCES 3. Hernandez EP, Talactac MR, Fujisaki K, Tanaka T. The Case for Oxidative Stress Molecule Involvement in the Tick-Pathogen Interactions -an Omics Approach. Dev Comp Immunol (2019) 100:103409. doi: 10.1016/ j.dci.2019.103409 1. Kohen R, Nyska A. Oxidation of Biological Systems: Oxidative Stress Phenomena, Antioxidants, Redox Reactions, and Methods for Their Quantification. Toxicol Pathol (2002) 30:620–50. doi: 10.1080/01926230290166724 1. Kohen R, Nyska A. Oxidation of Biological Systems: Oxidative Stress Phenomena, Antioxidants, Redox Reactions, and Methods for Their Quantification. Toxicol Pathol (2002) 30:620–50. doi: 10.1080/01926230290166724 4. Devriendt B, Stuyven E, Verdonck F, Goddeeris BM, Cox E. Enterotoxigenic Escherichia Coli (K88) Induce Proinflammatory Responses in Porcine Intestinal Epithelial Cells. Dev Comp Immunol (2010) 34(11):1175–82. doi: 10.1016/j.dci.2010.06.009 2. Muralidharan S, Mandrekar P. Cellular Stress Response and Innate Immune Signaling: Integrating Pathways in Host Defense and Inflammation. J Leukoc Biol (2013) 94(6):1167–84. doi: 10.1189/jlb.0313153 November 2021 | Volume 12 | Article 771826 Frontiers in Immunology | www.frontiersin.org 13 CB Alleviates Oxidative Damage Li et al. 23. Yang SH, Yu LH, Li L, Guo Y, Zhang Y, Long M, et al. Protective Mechanism of Sulforaphane on Cadmium-Induced Sertoli Cell Injury in Mice Testis via Nrf2/ARE Signaling Pathway. Molecules (2018) 23:1774. doi: 10.3390/ molecules23071774 5. Gong Y, Jin X, Yuan B, Lv Y, Yan G, Liu M, et al. G Protein-Coupled Receptor 109A Maintains the Intestinal Integrity and Protects Against ETEC Mucosal Infection by Promoting IgA Secretion. Front Immunol (2021) 11:583652. doi: 10.3389/fimmu.2020.583652 6. Mirhoseini A, Amani J, Nazarian S. Review on Pathogenicity Mechanism of Enterotoxigenic Escherichia Coli and Vaccines Against it. Microb Pathog (2018) 117:162–9. doi: 10.1016/j.micpath.2018.02.032 24. Li C, Tan F, Yang J, Yang Y, Gou Y, Li S, et al. Antioxidant Effects of Apocynum Venetum Tea Extracts on D-Galactose-Induced Aging Model in Mice. Antioxidants (Basel) (2019) 8:381. doi: 10.3390/antiox8090381 7. Yacoub AM, Sabra S, Kourashi MA. Pathological Changes in Liver Structure and Function of Oreochromis Niloticus Experimentally Exposed to Escherichia Coli. Int J Biotech Bioeng (2017) 3:95–106. doi: 10.25141/2475- 3432-2017-4.0095 25. Ruan YC, Wang Y, Da Silva N,Kim B, Diao RY, Hill E,et al. CFTR InteractsWith ZO-1toRegulateTightJunctionAssemblyandEpithelialDifferentiationThrough the ZONAB Pathway. J Cell Sci (2014) 127:4396–408. doi: 10.1242/jcs.148098 26. Sassi A, Wang Y, Chassot A, Komarynets O, Roth I, Olivier V, et al. Interaction Between Epithelial Sodium Channel g-Subunit and Claudin-8 Modulates Paracellular Sodium Permeability in Renal Collecting Duct. J Am Soc Nephrol (2020) 31:1009–23. doi: 10.1681/ASN.2019080790 8. REFERENCES Tang Z, Yin Y, Zhang Y, Huang R, Sun Z, Li T, et al. Effects of Dietary Supplementation With an Expressed Fusion Peptide Bovine Lactoferricin- Lactoferrampin on Performance, Immune Function and Intestinal Mucosal Morphology in Piglets Weaned at Age 21 D. Br J Nutr (2009) 101:998–1005. doi: 10.1017/S0007114508055633 27. Li XF, Zhang XJ, Zhang C, Wang LN, Li YR, Zhang Y, et al. Ulinastatin Protects Brain Against Cerebral Ischemia/Reperfusion Injury Through Inhibiting MMP-9 and Alleviating Loss of ZO-1 and Occludin Proteins in Mice. Exp Neurol (2018) 302:68–74. doi: 10.1016/j.expneurol.2017.12.016 9. Ducarmon QR, Zwittink RD, Hornung BVH, van Schaik W, Young VB, Kuijper EJ. Gut Microbiota and Colonization Resistance Against Bacterial Enteric Infection. Microbiol Mol Biol Rev (2019) 83:e00007–19. doi: 10.1128/ MMBR.00007-19 28. Magoč T, Salzberg SL. FLASH: Fast Length Adjustment of Short Reads to Improve Genome Assemblies. Bioinformatics (2011) 27:2957–63. doi: 10.1093/bioinformatics/btr507 10. Loboda A, Damulewicz M, Pyza E, Jozkowicz A, Dulak J. Role of Nrf2/HO-1 System in Development, Oxidative Stress Response and Diseases: An Evolutionarily Conserved Mechanism. Cell Mol Life Sci (2016) 73:3221–47. doi: 10.1007/s00018-016-2223-0 29. Haas BJ, Gevers D, Earl AM, Feldgarden M, Ward DV, Giannoukos G, et al. Chimeric 16s rRNA Sequence Formation and Detection in Sanger and 454- Pyrosequenced PCR Amplicons. Genome Res (2011) 21:494–504. doi: 10.1101/gr.112730.110 11. Wen Z, Liu W, Li X, Chen W, Liu Z, Wen J, et al. A Protective Role of the NRF2-Keap1 Pathway in Maintaining Intestinal Barrier Function. Oxid Med Cell Longev (2019) 2019:1759149. doi: 10.1155/2019/1759149 30. Wang Q, Garrity GM, Tiedje JM, Cole JR. Naive Bayesian Classifier for Rapid Assignment of rRNA Sequences Into the New Bacterial Taxonomy. Appl Environ Microbiol (2007) 73:5261–7. doi: 10.1128/AEM.00062-07 12. Bartolini D, Dallaglio K, Torquato P, Piroddi M, Galli F. Nrf2-P62 Autophagy Pathway and its Response to Oxidative Stress in Hepatocellular Carcinoma. Transl Res (2018) 193:54–71. doi: 10.1016/j.trsl.2017.11.007 31. Edgar RC. UPARSE: Highly Accurate OTU Sequences From Microbial Amplicon Reads. Nat Methods (2013) 10:996–8. doi: 10.1038/nmeth.2604 13. Liu Y, Kern JT, Walker JR, Johnson JA, Schultz PG, Luesch H. A Genomic Screen for Activators of the Antioxidant Response Element. Proc Natl Acad Sci USA (2007) 104:5205–10. doi: 10.1073/pnas.0700898104 32. Valko M, Rhodes CJ, Moncol J, Izakovic M, Mazur M. Free Radicals, Metals and Antioxidants in Oxidative Stress-Induced Cancer. Chem Biol Interact (2006) 160:1–40. doi: 10.1016/j.cbi.2005.12.009 14. Kayama H, Okumura R, Takeda K. Interaction Between the Microbiota, Epithelia, and Immune Cells in the Intestine. REFERENCES Annu Rev Immunol (2020) 38:23–48. doi: 10.1146/annurev-immunol-070119-115104 33. Chang Y, Cai H, Liu G, Chang W, Zheng A, Zhang S, et al. Effects of Dietary Leucine Supplementation on the Gene Expression of Mammalian Target of Rapamycin Signaling Pathway and Intestinal Development of Broilers. Anim Nutr (2015) 1:313–9. doi: 10.1016/j.aninu.2015.11.005 15. Liu L, Zeng D, Yang M, Wen B, Lai J, Zhou Y, et al. Probiotic Clostridium Butyricum Improves the Growth Performance, Immune Function, and Gut Microbiota of Weaning Rex Rabbits. Probiotics Antimicrob Proteins (2019) 11:1278–92. doi: 10.1007/s12602-018-9476-x 34. Taylor SR, Ramsamooj S, Liang RJ, Katti A, Pozovskiy R, Vasan N, et al. Dietary Fructose Improves Intestinal Cell Survival and Nutrient Absorption. Nature (2021) 597(7875):263–7. doi: 10.1038/s41586-021-03827-2 16. Kong Q, He GQ, Jia JL, Zhu QL, Ruan H. Oral Administration of Clostridium Butyricum for Modulating Gastrointestinal Microflora in Mice. Curr Microbiol (2011) 62:512–7. doi: 10.1007/s00284-010-9737-8 35. Rao RK, Basuroy S, Rao VU, Karnaky KJJr, Gupta A. Tyrosine Phosphorylation and Dissociation of Occludin-ZO-1 and E-Cadherin-Beta- Catenin Complexes From the Cytoskeleton by Oxidative Stress. Biochem J (2002) 368:471–81. doi: 10.1042/BJ20011804 17. Zhao X, Yang J, Ju Z, Wu J, Wang L, Lin H, et al. Clostridium Butyricum Ameliorates Salmonella Enteritis Induced Inflammation by Enhancing and Improving Immunity of the Intestinal Epithelial Barrier at the Intestinal Mucosal Level. Front Microbiol (2020) 11:299. doi: 10.3389/fmicb.2020.00299 36. Roselli M, Finamore A, Britti MS, Konstantinov SR, Smidt H, de Vos WM, et al. The Novel Porcine Lactobacillus Sobrius Strain Protects Intestinal Cells From Enterotoxigenic Escherichia Coli K88 Infection and Prevents Membrane Barrier Damage. J Nutr (2007) 137:2709–16. doi: 10.1093/jn/ 137.12.2709 18. Li H, Liu X, Shang Z, Qiao J. Clostridium Butyricum Helps to Alleviate Inflammation in Weaned Piglets Challenged With Enterotoxigenic Escherichia coli K88. Front Vet Sci (2021) 8:683863. doi: 10.3389/ fvets.2021.683863 37. Chen L, Li S, Zheng J, Li W, Jiang X, Zhao X, et al. Effects of Dietary Clostridium Butyricum Supplementation on Growth Performance, Intestinal Development, and Immune Response of Weaned Piglets Challenged With Lipopolysaccharide. J Anim Sci Biotechnol (2018) 9:62. doi: 10.1186/s40104- 018-0275-8 19. Liu J, Fu Y, Zhang H, Wang J, Zhu J, Wang Y, et al. The Hepatoprotective Effect of the Probiotic Clostridium Butyricum Against Carbon Tetrachloride- Induced Acute Liver Damage in Mice. Food Funct (2017) 8:4042–52. doi: 10.1039/c7fo00355b 38. Poprac P, Jomova K, Simunkova M, Kollar V, Rhodes CJ, Valko M. Targeting Free Radicals in Oxidative Stress-Related Human Diseases. REFERENCES Trends Pharmacol Sci (2017) 38:592–607. doi: 10.1016/j.tips.2017.04.005 20. Li J, Shen H, Zhao Z, Cao D, Zeng M, Cai H, et al. Protective Effects of Clostridium Butyricum Against Oxidative Stress Induced by Food Processing and Lipid-Derived Aldehydes in Caco-2 Cells. Appl Microbiol Biotechnol (2020) 104:9343–61. doi: 10.1007/s00253-020-10896-2 39. Lehoux S. Redox Signalling in Vascular Responses to Shear and Stretch. Cardiovasc Res (2006) 71:269–79. doi: 10.1016/j.cardiores.2006.05.008 21. Sun Z, Li H, Li Y, Qiao J. Lactobacillus Salivarius, a Potential Probiotic to Improve the Health of LPS-Challenged Piglet Intestine by Alleviating Inflammation as Well as Oxidative Stress in a Dose-Dependent Manner During Weaning Transition. Front Vet Sci (2020) 7:547425. doi: 10.3389/ fvets.2020.547425 40. Fridlyand LE, Philipson LH. Oxidative Reactive Species in Cell Injury: Mechanisms in Diabetes Mellitus and Therapeutic Approaches. Ann N Y Acad Sci (2005) 1066:136–51. doi: 10.1196/annals.1363.019 41. Ho E, Karimi Galougahi K, Liu CC, Bhindi R, Figtree GA. Biological Markers of Oxidative Stress: Applications to Cardiovascular Research and Practice. Redox Biol (2013) 1:483–91. doi: 10.1016/j.redox.2013.07.006 22. Chen X, Xi Z, Liang H, Sun Y, Zhong Z, Wang B, et al. Melatonin Prevents Mice Cortical Astrocytes From Hemin-Induced Toxicity Through Activating Pkca/Nrf2/HO-1 Signaling In Vitro. Front Neurosci (2019) 13:760. doi: 10.3389/fnins.2019.00760 42. Li T, Jiang D, Wu K. P62 Promotes Bladder Cancer Cell Growth by Activating KEAP1/NRF2-Dependent Antioxidative Response. Cancer Sci (2020) 111 (4):1156–64. doi: 10.1111/cas.14321 November 2021 | Volume 12 | Article 771826 Frontiers in Immunology | www.frontiersin.org 14 CB Alleviates Oxidative Damage Li et al. Li et al. 55. Jacobson A, Lam L, Rajendram M, Tamburini F, Honeycutt J, Pham T, et al. A Gut Commensal-Produced Metabolite Mediates Colonization Resistance to Salmonella Infection. Cell Host Microbe (2018) 24:296–307.e7. doi: 10.1016/ j.chom.2018.07.002 43. Dou C, Shang Z, Qiao J, Wang Y, Li H. Clostridium Butyricum Protects IPEC- J2 Cells From ETEC K88-Induced Oxidative Damage by Activating the Nrf2/ ARE Signaling Pathway. Oxid Med Cell Longev (2021) 2021:4464002. doi: 10.1155/2021/4464002 44. Gagnière J, Raisch J, Veziant J, Barnich N, Bonnet R, Buc E, et al. Gut Microbiota Imbalance and Colorectal Cancer. World J Gastroenterol (2016) 22 (2):501–18. doi: 10.3748/wjg.v22.i2.501 56. Morrison DJ, Preston T. Formation of Short Chain Fatty Acids by the Gut Microbiota and Their Impact on Human Metabolism. Gut Microbes (2016) 7:189–200. doi: 10.1080/19490976.2015.1134082 57. Tong LC, Wang Y, Wang ZB, Liu WY, Sun S, Li L, et al. REFERENCES Propionate Ameliorates Dextran Sodium Sulfate-Induced Colitis by Improving Intestinal Barrier Function and Reducing Inflammation and Oxidative Stress. Front Pharmacol (2016) 7:253. doi: 10.3389/fphar.2016.00253 45. Wang QP, Browman D, Herzog H, Neely GG. Non-Nutritive Sweeteners Possess a Bacteriostatic Effect and Alter Gut Microbiota in Mice. PloS One (2018) 13:e0199080. doi: 10.1371/journal.pone.0199080 46. Horn N. Clostridium Disporicum Sp. Nov. A Saccharolytic Species Able to Form Two Spores Per Cell, Isolated From a Rat Cecum. Int J Syst Bacteriol (1987) 37:398–401. doi: 10.1099/00207713-37-4-398 58. Meehan CJ, Beiko RG. A Phylogenomic View of Ecological Specialization in the Lachnospiraceae, a Family of Digestive Tract-Associated Bacteria. Genome Biol Evol (2014) 6:703–13. doi: 10.1093/gbe/evu050 47. Vilajeliu-Pons A, Puig S, Pous N, Salcedo-Dávila I, Bañeras L, Balaguer MD, et al. Microbiome Characterization of MFCs Used for the Treatment of Swine Manure. J Hazard Mater (2015) 288:60–8. doi: 10.1016/j.jhazmat.2015.02.014 59. Cai C, Zhang Z, Morales M, Wang Y, Khafipour E, Friel J. Feeding Practice Influences Gut Microbiome Composition in Very Low Birth Weight Preterm Infants and the Association With Oxidative Stress: A Prospective Cohort Study. Free Radic Biol Med (2019) 142:146–54. doi: 10.1016/ j.freeradbiomed.2019.02.032 48. Mangin I, Bonnet R, Seksik P, Rigottier-Gois L, Sutren M, Bouhnik Y, et al. Molecular Inventory of Faecal Microflora in Patients With Crohn's Disease. FEMS Microbiol Ecol (2004) 50:25–36. doi: 10.1016/j.femsec.2004.05.005 60. Shin NR, Lee JC, Lee HY, Kim MS, Whon TW, Lee MS, et al. An Increase in the Akkermansia Spp. Population Induced by Metformin Treatment Improves Glucose Homeostasis in Diet-Induced Obese Mice. Gut (2014) 63:727–35. doi: 10.1136/gutjnl-2012-303839 49. Andrejčáková Z, Sopková D, Vlčková R, Hertelyová Z, Gancarčı́ková S, Nemcová R. The Application of Lactobacillus Reuteri CCM 8617 and Flaxseed Positively Improved the Health of Mice Challenged With Enterotoxigenic E. Coli O149:F4. Probiotics Antimicrob Proteins (2020) 12:937–51. doi: 10.1007/s12602-019-09578-x Conflict of Interest: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. 50. Mazal C, Sieger B. Staphylococcus Lentus: The Troublemaker. Int J Infect Dis (2010) 14:e397–7. doi: 10.1016/j.ijid.2010.02.502 51. Cassir N, Benamar S, La Scola B. Clostridium Butyricum: From Beneficial to a New Emerging Pathogen. Clin Microbiol Infect (2016) 22:37–45. November 2021 | Volume 12 | Article 771826 REFERENCES doi: 10.1016/ j.cmi.2015.10.014 Publisher’s Note: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher. 52. Leshem A, Liwinski T, Elinav E. Immune-Microbiota Interplay and Colonization Resistance in Infection. Mol Cell (2020) 78:597–613. doi: 10.1016/j.molcel.2020.03.001 53. Kelly CJ, Zheng L, Campbell EL, Saeedi B, Scholz CC, Bayless AJ, et al. Crosstalk Between Microbiota-Derived Short-Chain Fatty Acids and Intestinal Epithelial HIF Augments Tissue Barrier Function. Cell Host Microbe (2015) 17:662–71. doi: 10.1016/j.chom.2015.03.005 Copyright © 2021 Li, Shang, Liu, Qiao, Wang and Qiao. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. 54. Xiong H, Guo B, Gan Z, Song D, Lu Z, Yi H, et al. Butyrate Upregulates Endogenous Host Defense Peptides to Enhance Disease Resistance in Piglets via Histone Deacetylase Inhibition. Sci Rep (2016) 6:27070. doi: 10.1038/ srep27070 November 2021 | Volume 12 | Article 771826 Frontiers in Immunology | www.frontiersin.org 15
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Growth hormone inhibits adipogenic differentiation and induces browning in bovine subcutaneous adipocytes
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Growth hormone inhibits adipogenic differentiation and induces browning in bovine subcutaneous adipocytes Tingting Li  Nanjing Agricultural University Hui Bai  Nanjing Agricultural University Haoyuan Fang  Nanjing Agricultural University Liang Yang  Nanjing Agricultural University Peishi Yan Research Article Keywords: Growth hormone, Adipocyte, Bovine, STAT5B Posted Date: May 13th, 2022 DOI: https://doi.org/10.21203/rs.3.rs-1640988/v1 License:   This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License License:   This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Additional Declarations: No competing interests reported. Version of Record: A version of this preprint was published at Growth Hormone & IGF Research on October 1st, 2022. See the published version at https://doi.org/10.1016/j.ghir.2022.101498. Page 1/22 Page 1/22 Abstract It is well established that growth hormone (GH) has the ability to stimulate lipolysis. The effects of GH on adipocyte differentiation and browning have not been clearly described. Therefore, the present study aimed to elucidate the role of GH in the differentiation and browning of bovine subcutaneous adipocytes as well as its underlying molecular mechanisms. In this study, we demonstrated that GH inhibited lipid accumulation and decreased the expression levels of adipogenic key genes (SCD1, SREBP1, PPARγ, and CEBPα) during adipocyte differentiation. Moreover, we observed that the inhibitory effect of GH on the early stage of adipocyte differentiation (0–2 days) was stronger than that on the later stage of adipocyte differentiation (2–8 days). We also found that GH promoted the expression levels of browning-related genes such as uncoupling protein 1 (UCP1) in mature adipocytes. Concurrently, GH promoted mitochondrial biogenesis and increased the expression levels of mitochondrial biogenesis-related genes. In addition, GH promoted phosphorylation of signal transducers and activator of transcription 5 b (STAT5B) and contributed to translocation of STAT5B to nucleus. After blocking the expression of STAT5B protein, GH weakened the inhibition of adipogenic key genes and reduced the promotion of browning-related genes in bovine subcutaneous adipocytes. To sum up, our findings indicate that GH inhibits adipocyte differentiation and promotes adipocyte browning by regulating STAT5B in bovine subcutaneous adipocytes. Introduction As an important endocrine organ, adipose tissue can regulate energy balance and maintain metabolic homeostasis in the body [1]. Traditionally, there are two colors of adipose tissues in humans and animals, white and brown. Recent studies have found that the white adipocytes from white adipose tissue (WAT) can be converted into beige or brite adipocytes in response to external stimuli such as cold or drugs [2, 3]. Adipocytes with different colors have different functions, white adipocytes store energy, while brown and beige adipocytes consume energy to produce heat [4]. The main reason for the different metabolic types of adipocytes is the difference in mitochondrial content [5]. Compared with white adipocytes, brown and beige adipocytes have more mitochondria to produce heat through the uncoupling protein 1 (UCP1) rather than catalyzing ATP synthesis [6]. Since the process of browning can consume excess energy and reduce fat deposition, thus combating obesity and related metabolic diseases, more and more studies attempt to identify regulatory factors that can promote the browning of white adipocytes. The differentiation of adipocytes is the key process for adipogenesis in adipose tissue and is regulated by many transcription factors. Peroxisome proliferator-activated receptor gamma (PPARγ) has been reported to significantly promote adipocyte differentiation, and the differentiation is inhibited by the knockout of PPARγ [7, 8]. Moreover, CCAAT enhancer binding protein alpha (CEBPα) is also a key transcription factor regulating adipogenic differentiation, which promotes differentiation combined with PPARγ [9]. In adipocytes cultured in vitro, the differentiation of adipocytes is often induced by a medium containing MDI (insulin + IBMX + dexamethasone). Notably, increasing evidence reveals that adding Page 2/22 Page 2/22 triiodothyronine, CL316243, and rosiglitazone to the medium during the induction stage of differentiation can induce white adipocytes to become beige adipocytes [10–12]. This provides a new insight for the study on inducing the browning of adipocytes in vitro. triiodothyronine, CL316243, and rosiglitazone to the medium during the induction stage of differentiation can induce white adipocytes to become beige adipocytes [10–12]. This provides a new insight for the study on inducing the browning of adipocytes in vitro. Growth hormone (GH) is a kind of polypeptide hormone, which participates in the regulation of body growth and development. GH possesses multiple biological functions, especially regulating fat deposition in adipose tissue. Previous studies have shown that GH treatment can significantly reduce the fat mass of mice [13, 14]. Introduction A study on human subcutaneous adipose tissue has also reported that GH supplementation markedly reduced the size of adipocytes [15]. These studies indicate that GH level is negatively correlated with adipose tissue content. In addition, research has disclosed that GH has a significant impact on fat distribution, and the content of subcutaneous WAT in GH knockout mice is quite higher than that in perigonadal WAT [16]. Previous evidence also identified that the extra-/intraperitoneal WAT ratio was upregulated in GH receptor antagonist (GHA) mice [17]. Although the inhibitory effect of GH on fat deposition has been widely confirmed, the effect of GH on adipocytes is still controversial. Accumulating evidences have reported that GH can promote the adipocyte differentiation of 3T3-L1 and 3T3-F442A, the cell lines from mice [18–20]. Inversely, the adipogenic differentiation of preadipocytes in primary cultures has been significantly inhibited during GH treatment [21, 22]. Furthermore, GH is also important in inducing WAT browning. For example, GH remarkably increases the expression level of UCP1 gene in subcutaneous WAT from mice [23]. To date, the ability of GH to induce the browning of adipocytes, especially subcutaneous adipocytes, has not been extensively studied. Signal transducers and activator of transcription 5 (STAT5) protein plays a pivotal role in the regulation of fat deposition by GH. Study has shown that STAT5 is activated in GH-treated mouse adipose tissue [24]. After STAT5 knockout, GH could not continue to stimulate lipolysis in mouse adipocytes and the fat mass was also increased in mice [25, 26]. STAT5 is divided into two subtypes, STAT5A and STAT5B. STAT5A mainly acts on mammary tissue, and researchers have found that STAT5A-deficient mice could not lactate normally [27]. It has been reported that STAT5A plays a role in promoting adipogenesis [28]. In contrast, STAT5B has been reported to inhibit adipocyte differentiation [29]. Therefore, the regulation of GH on STAT5B may be the key for GH to inhibit the differentiation of preadipocytes in primary cultures. Although the lipolysis of GH on adipose tissue has been established, the effect of GH on the differentiation and browning of bovine subcutaneous adipocytes remains unclear. In this study, we treated bovine subcutaneous preadipocytes with GH to detect the indicators related to differentiation and browning, and measured the expression of STAT5B protein during GH treatment. These results provide a theoretical basis for future studies into the mechanism of GH on fat metabolism of bovine subcutaneous adipocytes. Materials and reagents Page 3/22 GH was purchased from Prospec (Ness-Ziona, Israeli). Phosphate buffer saline (PBS), penicillin and streptomycin, and Dulbecco’s modified Eagle’s medium/nutrient mixture F12 (DMEM/F12) were obtained from Hyclone (Logan, UT, USA). Fetal bovine serum (FBS) was purchased from Sciencell (Carlsbad, CA, USA). Type I collagenase, insulin, rosiglitazone, dexamethasone, 3-isobutyl-1-methylxanthine (IBMX), and oil red O were purchased from Sigma-Aldrich (St. Louis, MO, USA). MitoTracker Red was purchased from Warbio (Nanjing, Jiangsu, China). Cell counting kit 8 (CCK-8), BCA assay kit, and ECL kit were purchased from Vazyme (Nanjing, Jiangsu, China). Bovine serum albumin (BSA), DAPI, RIPA buffer, and protease inhibitor were purchased from Beyotime (Shanghai, China). Genomic DNA Extraction Kit, Trizol, PrimeScript™ RT Master Mix, and SYBR Premix were purchased from TaKaRa (Tokyo, Japan). STAT5-IN-1 was purchased from Selleck (Houston, Texas, USA). GH was purchased from Prospec (Ness-Ziona, Israeli). Phosphate buffer saline (PBS), penicillin and streptomycin, and Dulbecco’s modified Eagle’s medium/nutrient mixture F12 (DMEM/F12) were obtained from Hyclone (Logan, UT, USA). Fetal bovine serum (FBS) was purchased from Sciencell (Carlsbad, CA, USA). Type I collagenase, insulin, rosiglitazone, dexamethasone, 3-isobutyl-1-methylxanthine (IBMX), and oil red O were purchased from Sigma-Aldrich (St. Louis, MO, USA). MitoTracker Red was purchased from Warbio (Nanjing, Jiangsu, China). Cell counting kit 8 (CCK-8), BCA assay kit, and ECL kit were purchased from Vazyme (Nanjing, Jiangsu, China). Bovine serum albumin (BSA), DAPI, RIPA buffer, and protease inhibitor were purchased from Beyotime (Shanghai, China). Genomic DNA Extraction Kit, Trizol, PrimeScript™ RT Master Mix, and SYBR Premix were purchased from TaKaRa (Tokyo, Japan). STAT5-IN-1 was purchased from Selleck (Houston, Texas, USA). Cell culture and adipogenic differentiation Bovine subcutaneous primary adipocytes were isolated from the subcutaneous adipose tissue in Simmental cattle. Firstly, the isolated adipose tissue samples were washed with PBS, minced with scissors, and digested with type I collagenase at 37 °C for 1 h. Next, the digested cell suspensions were filtered through the cell strainer, then centrifuged, re-suspended in a standard medium. The standard medium was DMEM/F12 supplemented with 10% FBS and 100 U/mL penicillin and streptomycin. Finally, the preadipocytes were incubated in a humidified atmosphere of 5% CO2 at 37°C. The culture medium was changed every 2 days. To induce adipogenic differentiation, the fully confluent preadipocytes were cultured in a standard medium for 2 days (day 0), then cultured in a differentiation medium for 6 days and finally cultured in a standard medium containing 1 μg/mL insulin for 2 days. The differentiation medium comprised of standard medium supplemented with 1 μg/mL insulin, 2 μM rosiglitazone, 1 μM dexamethasone, and 0.5 mM IBMX. Cell viability assay Bovine subcutaneous preadipocytes were seeded in a 96-well plate and incubated at 37℃ for 24 h. Next, the preadipocytes were treated with GH of various concentrations (0, 10, 100, 500 ng/mL) for 48 h. Afterward, 10 μL of CCK8 solution was added to each well and incubated at 37℃ for 4 h. The absorbance value was measured at 450 nm by using a microplate reader (Tecan, Switzerland). Oil red O staining After 8 days of adipogenic differentiation, adipocytes were washed with PBS and fixed in 4% paraformaldehyde for 30 min. Adipocytes were then washed with PBS three times and stained with oil red O working solution for 1 h at room temperature in dark. After washing with doubly distilled water 3-6 times, adipocytes were observed and photographed with a light microscope (CKX41, Olympus, Japan). Lipid contents in adipocytes were extracted with 100% isopropanol and the absorbance value at 510 nm was read by a microplate reader (Tecan, Switzerland). Real-time quantitative PCR (RT-qPCR) analysis Real-time quantitative PCR (RT-qPCR) analysis Page 4/22 Page 4/22 Page 4/22 Total RNA was extracted from adipocytes by using Trizol. After that, total RNA was used as a template for cDNA synthesis by using PrimeScript™ RT Master Mix. RT-qPCR was performed with the mixture of SYBR Premix, primers, and cDNA on a QuantStudio 5 system (ABI, Carlsbad, CA, USA). Details of the primer sequences for acetyl-CoA carboxylase (ACC), stearoyl-Coenzyme A desaturase 1 (SCD1), sterol regulatory element binding protein 1 (SREBP1), PPARγ, CEBPα, UCP1, peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α), PR domain containing 16 (PRDM16), cluster of differentiation 137 (CD137), T-box transcription factor 1 (TBX1), cell death inducing DFFA like effector A (CIDEA), deiodinase-2 (DIO2), mitochondrial transcription factors A (TFAM), nuclear respiratory factor 1 (NRF1), nuclear respiratory factor 2 (NRF2), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) are shown in Table 1. The expression level of relative genes was calculated using 2−∆∆Ct method and normalized to GAPDH [30]. Primers sequences for target and reference genes. Primers sequences for target and reference genes. Page 5/22 Gene Gene ID Primer sequences (5' to 3') Product size (bp) ACC NM_174224.2 F: GCTATGGAAGTCGGCTGTGGAAG R: GGAAGAGGCGGATGGGAATTGC 102 SCD1 NM_173959.4 F: CTACACAACCACCACCACCATCAC R: CTCTCATTTCAGGGCGGATGTCTTC 116 SREBP1 NM_001113302.1 F: CTCCGACACCACCAGCATCAAC R: GCAGCCCATTCATCAGCCAGAC 122 PPARγ NM_181024.2 F: TTGACCCAGAGAGTGAGCCCTTC R: CCACGGAGCTGATCCCAAAGTTG 117 CEBPα NM_176784. 2 F: TGGACAAGAACAGCAACGAGTACC R: GGCGGTCATTGTCACTGGTCAG 138 UCP1 NM_001166528.1 F: TGCGTGGCTGACATAATCACCTTC R: GGCACTGGAGATCAGGCATTCG 96 PGC-1α XM_024993058.1 F: AGGCAGAGGCAGAAGGCAATTAAC R: CCTCAGTTCTGTCCGTGTTGTGTC 117 PRDM16 XM_024976786.1 F: CTTGGAGCAGCACATGGTCGTC R: TCTGGTGGCGGATGAGGTTGG 101 CD137 NM_001035336.2 F: TGGCGTCCTTCCTGGTTCTCC R: CCTCTTGGGCTGTTTGTACTGGTC 108 TBX1 XM_024977887.1 F: GCAGTCACCGCCTATCAGAATCAC R: GTCACAGTCTCGGAAGCCTTTGG 84 CIDEA NM_001083449.1 F: CCTTCCGTGTCTCCAACCATGAC R: GCGACCACCAGTGCATCCAAG 100 DIO2 NM_001010992.7 F: CATCCGTGGCTGACTTCCTGTTG R: CTTCCTGGTTCCGGTGCTTCTTC 117 TFAM NM_001034016.2 F: AAACCGAAAAGACCTCGCTCAGC R: TACCTGTGATGTGCCATCCCTAGC 81 NRF1 NM_001098002.2 F: AATTATTCGGCGGTGGCTGATGG 82 Page 6/22 NRF2 NM_001011678.2 F: TCAGCCAGCACAACACATACCATC R: ACGGGAATGTCTCTGCCAAAAGC 128 ND1 NC_006853.1 F: CGTAGAATATGCAGCAGGACCA R: GTTCTGGTATGTGTGGATTGTGG 125 GAPDH NM_001034034.2 F: CGGCACAGTCAAGGCAGAGAAC R: CCACATACTCAGCACCAGCATCAC 116 ACC, acetyl-CoA carboxylase; SCD1, stearoyl-Coenzyme A desaturase 1; SREBP1, sterol regulatory element binding protein 1; PPARγ, peroxisome proliferator-activated receptor gamma; CEBPα, CCAAT enhancer binding protein alpha; UCP1, uncoupling protein 1; PGC-1α, peroxisome proliferator-activated receptor gamma coactivator 1 alpha; PRDM16, PR domain containing 16; CD137, cluster of differentiation 137; TBX1, T-box transcription factor 1; CIDEA, cell death inducing DFFA like effector A; DIO2, deiodinase-2; TFAM, mitochondrial transcription factors A; NRF1, nuclear respiratory factor 1; NRF2, nuclear respiratory factor 2; ND1, NADH dehydrogenase subunit 1; GAPDH, glyceraldehyde-3- phosphate dehydrogenase. NRF2 NM_001011678.2 F: TCAGCCAGCACAACACATACCATC R: ACGGGAATGTCTCTGCCAAAAGC 128 ND1 NC_006853.1 F: CGTAGAATATGCAGCAGGACCA R: GTTCTGGTATGTGTGGATTGTGG 125 GAPDH NM_001034034.2 F: CGGCACAGTCAAGGCAGAGAAC R: CCACATACTCAGCACCAGCATCAC 116 Mitochondrial DNA (mtDNA) quantification Adipocytes were treated with GH and performed for DNA extraction using the genomic DNA extraction kit. The mtDNA content was quantitatively analyzed by normalizing the NADH dehydrogenase subunit 1 (ND1) gene to GAPDH using RT-qPCR. The primer sequences are available in Table 1. The mtDNA content was calculated by using the 2−∆∆Ct method [30]. Western blot analysis The lysates of adipocytes were harvested using the mixture of RIPA buffer and protease inhibitor. After centrifugation, the supernatant was quantified by a BCA assay kit and boiled with sodium dodecyl sulfate sample buffer. Then, the isolated protein was loaded and run on a sodium dodecyl sulfate- polyacrylamide gel electrophoresis and transferred onto PVDF membranes. The membranes were blocked with fat-free milk followed by incubation with primary antibodies against PPARγ (SC-7196, Santa Cruz, 1:1000), GAPDH (10494-1-AP, Proteintech, 1:1000), STAT5B (bs-1142R, Bioss, 1:1000), and phosphor-STAT5B (bs-5703R, Bioss, 1:1000). The membranes were incubated with secondary antibody (7074P2, CST, 1:4000) and visualized using an ECL kit on the ChemiDocTM imaging system (BIO-RAD, Hercules, CA, USA). MitoTracker red staining Bovine subcutaneous adipocytes were differentiated into mature adipocytes in 6-well plates with coverslips on the bottom. Mature adipocytes were treated with 500 ng/mL GH for 6 h and stained with 200 nM MitoTracker red at 37℃ for 30 min. After fixing with 4% paraformaldehyde and washing with PBS, adipocytes were stained with DAPI for 10 min. Finally, coverslips containing labeled adipocytes Page 7/22 Page 7/22 were mounted on microscopic slides and the images were obtained with a laser scanning confocal microscope (LSM900, Zeiss, Germany). Statistical analysis All data were analyzed by the independent sample t-test using SPSS 22.0 software (IBM, Chicago, IL, USA). Data were shown as mean ± standard error of the mean (SEM). The p-values less than 0.05 were considered statistically significant. Immunofluorescent staining Adipocytes were differentiated in culture plates with coverslips and then treated with GH for 1 h. Next, adipocytes were fixed with 4% paraformaldehyde for 15 min and permeabilized with 0.5% Triton X-100 for 30min. After blocking with 5% BSA for 1 h, adipocytes were incubated with STAT5B antibody (bs- 1142R, Bioss, 1:200) overnight at 4 °C followed by staining with the florescent secondary antibody for 50 min. Then, the nuclei of adipocytes were counterstained with DAPI for 5 min. Fluorescence images were taken with laser scanning confocal microscope (LSM900, Zeiss, Germany). GH promoted the browning and mitochondrial biogenesis of bovine subcutaneous adipocytes To study the effect of GH on the browning of mature adipocytes, we cultured adipocytes in a differentiation medium for 8 days and then treated the differentiated adipocytes with GH. The expression level of the browning key gene UCP1 was analyzed by RT-qPCR. As shown in Fig. 3a, the expression level of UCP1 gene was significantly increased in fully differentiated adipocytes treated with 500 ng/mL GH for 2 h and 6 h. Then, we examined the expression levels of browning-related genes (PGC-1α, PRDM16, CD137, TBX1, CIDEA, and DIO2) in mature adipocytes treated with 500 ng/mL GH for 6 h, and found that GH treatment significantly increased the expression levels of PGC-1α, PRDM16, TBX1, and CIDEA genes (Fig. 3b). Mitochondrial biogenesis is one of the key characteristics of browning. We observed that 6 h of GH treatment significantly increased the content of mtDNA in mature adipocytes, suggesting the increased mitochondrial number (Fig. 3c). MitoTracker red staining in mature adipocytes further demonstrated that GH treatment enhanced mitochondrial red fluorescence signal (Fig. 3d). In addition, mitochondrial biogenesis-specific markers NRF1 and NRF2 were up-regulated in GH-treated mature adipocytes (Fig. 3e). Together, the above results showed that GH promoted the browning and mitochondrial biogenesis of bovine subcutaneous adipocytes. GH inhibited the differentiation of bovine subcutaneous preadipocytes RT-qPCR results showed that the expression levels of SCD1, SREBP1, PPARγ, and CEBPα were significantly reduced after GH treatment for 1 day, and the expression levels of ACC, SCD1, SREBP1, PPARγ, and CEBPα were significantly decreased after GH treatment for 2 days (Fig. 2d-e). Western blot analysis showed that the expression level of PPARγ protein decreased significantly after GH treatment for both 1 and 2 days (Fig. 2f). To further understand the inhibitory mechanism of GH on the differentiation of adipocytes, we treated adipocytes with GH at different stages of adipogenic differentiation (Fig. 2a). Adipogenesis of adipocytes was detected by oil red O staining. Compared with untreated adipocytes, the lipid content was significantly decreased in adipocytes treated with 500 ng/mL GH at different stages (Fig. 2b-c). Interestingly, we observed that the inhibitory effect of GH on the early stage of adipocyte differentiation (0-2 days) was stronger compared to the later stage of adipocyte differentiation (2-8 days). Therefore, adipocytes were collected for analysis of adipogenic key genes and proteins after treatment with differentiation medium and GH for 1 and 2 days. RT-qPCR results showed that the expression levels of SCD1, SREBP1, PPARγ, and CEBPα were significantly reduced after GH treatment for 1 day, and the expression levels of ACC, SCD1, SREBP1, PPARγ, and CEBPα were significantly decreased after GH treatment for 2 days (Fig. 2d-e). Western blot analysis showed that the expression level of PPARγ protein decreased significantly after GH treatment for both 1 and 2 days (Fig. 2f). GH inhibited the differentiation of bovine subcutaneous preadipocytes Firstly, we detected the cytotoxicity of GH on bovine subcutaneous preadipocytes by CCK8 assay. After GH treatment for 48 h, the cell viability of preadipocytes was unchanged at concentrations as high as 500 ng/mL (Fig. 1a). To investigate the effect on the differentiation of preadipocytes to mature adipocytes by GH treatment, we treated preadipocytes with different concentrations (0, 10, 100, and 500 ng/mL) of GH for 8 days during adipocyte differentiation (Fig. 1b). Oil red O staining showed clear lipid droplets in differentiated adipocytes without GH treatment (Fig. 1c). However, treatment with GH for 8 days inhibited the accumulation of lipid droplets in differentiated adipocytes (Fig. 1c). Lipid extraction of adipocytes after staining with oil red O showed that 100 and 500 ng/mL GH treatments significantly reduced the lipid content of differentiated adipocytes (Fig. 1d). To further demonstrate the inhibitory effect of GH on adipogenesis, we examined the expression levels of adipogenesis-related genes (ACC, SCD1, SREBP1, PPARγ, and CEBPα) in differentiated adipocytes after 8 days of GH treatment. Compared with those in the 0 ng/mL GH treatment group, 10 ng/mL GH treatment significantly inhibited the expression level of SREBP1 gene, 100 ng/mL GH treatment significantly decreased the expression level of PPARγ gene, and the expression levels of SCD1, SREBP1, PPARγ, and CEBPα genes were significantly decreased in 500 ng/mL GH treatment group (Fig. 1e). These results suggested that GH inhibited the differentiation of bovine subcutaneous preadipocytes. GH strongly suppressed the differentiation of bovine subcutaneous adipocytes at the early stage of differentiation Page 8/22 To further understand the inhibitory mechanism of GH on the differentiation of adipocytes, we treated adipocytes with GH at different stages of adipogenic differentiation (Fig. 2a). Adipogenesis of adipocytes was detected by oil red O staining. Compared with untreated adipocytes, the lipid content was significantly decreased in adipocytes treated with 500 ng/mL GH at different stages (Fig. 2b-c). Interestingly, we observed that the inhibitory effect of GH on the early stage of adipocyte differentiation (0-2 days) was stronger compared to the later stage of adipocyte differentiation (2-8 days). Therefore, adipocytes were collected for analysis of adipogenic key genes and proteins after treatment with differentiation medium and GH for 1 and 2 days. STAT5B showed that STAT5B protein could be translocated to the nucleus to regulate gene transcription (Fig. 4c). STAT5B showed that STAT5B protein could be translocated to the nucleus to regulate gene transcription (Fig. 4c). GH-induced differentiation and browning of bovine subcutaneous adipocy To further determine the activation mechanism of GH on STAT5B, we treated adipocytes in the differentiation stage (day 0) with GH for 1 h, with or without pretreatment with 100 μM STAT5-IN-1 (STAT5 inhibitor) for 1 h. Western blot analysis showed that 100 µM STAT5-IN-1 treatment significantly inhibited the phosphorylation of STAT5B initiated by GH (Fig. 5a). Moreover, we treated adipocytes with 100 μM STAT5-IN-1 for 1 h followed by GH for 24 h during the differentiated process (day 0). We found that pretreatment with STAT5-IN-1 significantly alleviated the downregulation of PPARγ and SREBP1 genes after GH treatment (Fig. 5b). In addition, treatment on fully differentiated adipocytes with STAT5- IN-1 and GH for 1 h and 6 h, respectively, significantly inhibited GH-induced the upregulation of UCP1 and PGC-1α genes. These results indicated that GH may inhibit adipogenic differentiation and promote the browning of adipocytes by activating STAT5B. GH increased the phosphorylation of STAT5B in bovine subcutaneous adipocytes STAT5 is widely involved in growth and development processes including cell proliferation, differentiation, etc. As a subtype of STAT5, STAT5B can participate in the GH-regulated lipolysis process [31, 32]. Therefore, to clarify whether GH can activate the expression of STAT5B in bovine subcutaneous adipocytes, we first treated preadipocytes (day 0) with a differentiation medium and 500 ng/mL GH for indicated time to detect the phosphorylation level of STAT5B. Although incubation with GH for 10 min and 30 min had no significant effect on the phosphorylation level of STAT5B, 60 min and 180 min of GH treatment significantly increased the phosphorylation level of STAT5B (Fig. 4a). Then we treated fully differentiated adipocytes with 500 ng/mL GH for 1 h and 6 h and found that both 1 h and 6 h of GH treatment markedly promoted STAT5B activation (Fig. 4b). Furthermore, immunofluorescence staining of Page 9/22 Page 9/22 Discussion GH is an important cytokine in regulating the growth and development of the body, and accumulating evidences have shown that GH has a significant impact on adipose tissue metabolism [33, 34]. In particular, GH can suppress the differentiation of primary cell cultures [35]. Indeed, although GH has been found to promote the expression of UCP1 in mouse model, the specific regulation mechanisms need further research [23]. STAT5B is a key transcription factor in cell development regulated by GH, which can transmit extracellular signals to the nucleus and regulate cell metabolic activities [36]. Therefore, in this research, we investigated the effects of GH on the differentiation and browning of bovine subcutaneous adipocytes by culturing bovine subcutaneous adipocytes in vitro, and explored the role of STAT5B protein in the regulation of GH on bovine subcutaneous adipocytes. It has been well accepted that GH can promote lipolysis and reduce WAT weight in the body [37]. Research on primary human mesenchymal stromal cells (MSCs) has confirmed that GH inhibited adipocyte differentiation [21]. In the present study, we found that GH treatment for 8 days significantly inhibited the lipid content of bovine subcutaneous adipocytes, which is consistent with the results of Zhao et al. [38]. Olarescu et al. [35] also found that bovine GH (bGH) cells from mice subcutaneous WAT displayed a decreased lipid accumulation compared to wild-type (WT) cells. Adipocyte differentiation is promoted by many key transcription factors, among which PPARγ is the core regulator of entire terminal differentiation [39]. In addition, CEBPα promotes adipogenic differentiation through reciprocal positive feedback regulation with PPARγ [39]. SREBP1 can promote the expression of PPARγ and SCD1, and both SREBP1 and SCD1 play an important role in regulating de novo lipogenesis [40, 41]. Our results suggested that GH inhibited adipogenesis of bovine subcutaneous adipocytes by down-regulating the expression levels of PPARγ, CEBPα, SREBP1, and SCD1 genes. This is contrary to the results in 3T3-L1 adipocytes, in which GH can significantly elevate the expression level of PPARγ protein [18, 42]. This may Page 10/22 Page 10/22 further confirm the opposite effects of GH on cell lines and primary adipocytes. The early phase of differentiation is the most crucial phase to initiate and ensure the normal differentiation process. Our study revealed that GH treatment had a stronger inhibitory effect on lipid accumulation in the early stage (0–2 days) than that in the later stage (2–8 days). Discussion Additionally, we identified the inhibitory effect of GH on the expression of key genes and proteins during adipogenic differentiation. These findings suggested that GH exerted the ability to inhibit adipogenic differentiation, especially in the early stage of differentiation, through inhibiting lipid accumulation and the expression of adipogenic-related genes. The browning of WAT is essential for the body to combat obesity, resist cold and increase heat production. Accordingly, researches related to inducing browning by using in vitro and in vivo models have attracted increasing attention. Recent work showed that compared with WT mice, the expression of UCP1 protein in bGH transgenic mice was increased [43]. As a marker of beige adipocytes, UCP1 leads protons to leak through the inner membrane of mitochondria and thus converting electrochemical energy into heat, which plays a central role in heat production [44]. Our study demonstrated that GH treatment could significantly increase the expression levels of UCP1 and browning-related key genes (PGC-1α, PRDM16, TBX1, and CIDEA) in bovine subcutaneous adipocytes, indicating a potential role of GH in inducing beige fat-like characteristic. Moreover, Hayashi et al. [45] also proposed that GH induced the expression of UCP1 protein in 3T3-L1 cells, which was coincident with our results. Due to beige adipocytes requiring more mitochondria for metabolism and thermogenesis, mitochondrial biogenesis has become a marker process of browning. Research has shown that mitochondrial biogenesis is dominant in the process of beige adipocytes formation [46]. The mtDNA replication is the main feature of mitochondrial biogenesis, which reflects the increase of mitochondrial number. In this study, GH treatment can increase mtDNA contents in bovine subcutaneous adipocytes. In addition, MitoTracker staining further demonstrated that GH treatment promoted mitochondrial biogenesis in bovine subcutaneous adipocytes. TFAM, NRF1, and NRF2 are key regulatory factors controlling mitochondrial biogenesis, and PGC-1α can activate the expression of these key transcription factors, led to an increase in mtDNA content, thus promoting mitochondrial biogenesis [47, 48]. In this work, we demonstrated that the expression levels of PGC-1α, NRF1, and NRF2 genes were increased in GH-treated adipocytes. Overall, these findings indicated that GH can induce the browning of bovine subcutaneous adipocytes and promote the mitochondrial biogenesis. There is increasing evidence that GH has the potential to activate STAT5B both in vivo and in vitro [18, 49]. Conclusion In conclusion, our data prove that GH can inhibit the adipogenic differentiation of bovine subcutaneous preadipocytes, and the inhibitory effect of GH is more obvious in the early stage of differentiation than that in the later stage. GH can also promote the browning of bovine subcutaneous adipocytes, accompanied by mitochondrial biogenesis. In addition, studies on STAT5B, a key factor in transcriptional regulation, found that GH regulated the differentiation and browning process of bovine subcutaneous adipocytes through activating STAT5B. Collectively, our results suggest the inhibitory effect of GH on the differentiation of preadipocytes and the feasibility of GH to induce the browning of adipocytes in vitro. Data availability The data that support the findings of the current study are available from the corresponding author on reasonable request. Funding This study was supported by the National Key Research and Development Plan of China (2016YFD0500508). Discussion Previous data have suggested that the expression of STAT5B protein was increased during adipocyte differentiation, and STAT5B knockdown up-regulated the expression of PPARγ and CEBPα [29, 50]. Moreover, several studies also confirmed that STAT5 promoted transcription by binding to the UCP1 promoter and cold exposure could not promote UCP1 protein increase in STAT5-deficient mice [45, 51]. Therefore, we hypothesized that GH could activate STAT5B expression to regulate the differentiation and browning of bovine subcutaneous adipocytes. As expected, our results showed that GH can activate STAT5B in differentiating as well as full differentiated adipocytes, suggesting that STAT5B plays an important role in GH-regulated differentiation and browning processes. STAT5B is widely present in the cytoplasm as a monomer when cells are not stimulated by cytokines and hormones. In response to GH Page 11/22 Page 11/22 stimulation, phosphorylated STAT5B separates from its receptor and forms different polymeric forms, which are transferred to the nucleus and activate or inhibit transcription by binding to specific DNA sequences [52]. This transcriptional regulation of nuclear translocation is the key for STAT5B to fulfill its function. In this study, STAT5B protein was translocated to the nucleus after GH treatment in bovine subcutaneous adipocytes. Consistent with our findings, it has been reported that GH promotes mitochondrial biogenesis by activating STAT5, which is then transported to the nucleus and interacts synergistically with other growth factors [53]. Next, we used STAT5-IN-1 to block the activity of STAT5B and found that the expression level of key genes involved in adipocyte differentiation and browning decreased significantly, indicating that GH inhibits adipocyte differentiation and promotes adipocyte browning in vitro by activating the expression of STAT5B protein. Author contributions TL performed the main experiments and drafted the manuscript. TL and HB designed this study. TL and HF carried out the data collection and analysis. TL and LY performed the material preparation. PY supervised the research and revised the manuscript. All authors reviewed and approved the final manuscript. References 1. Kershaw EE, Flier JS (2004) Adipose tissue as an endocrine organ. J Clin Endocrinol Metab 89(6):2548-2556. https://doi.org/10.1210/jc.2004-0395 1. Kershaw EE, Flier JS (2004) Adipose tissue as an endocrine organ. J Clin Endocrinol Metab 89(6):2548-2556. https://doi.org/10.1210/jc.2004-0395 2. Rosenwald M, Perdikari A, Rülicke T, Wolfrum C (2013) Bi-directional interconversion of brite and white adipocytes. Nat Cell Biol 15(6):659-667. https://doi.org/10.1038/ncb2740 2. Rosenwald M, Perdikari A, Rülicke T, Wolfrum C (2013) Bi-directional interconversion of brite and white adipocytes. Nat Cell Biol 15(6):659-667. https://doi.org/10.1038/ncb2740 3. Vargas-Castillo A, Fuentes-Romero R, Rodriguez-Lopez LA, Torres N, Tovar AR (2017) Understanding the biology of thermogenic fat: Is browning a new approach to the treatment of obesity? Arch Med Res 48(5):401-413. https://doi.org/10.1016/j.arcmed.2017.10.002 3. Vargas-Castillo A, Fuentes-Romero R, Rodriguez-Lopez LA, Torres N, Tovar AR (2017) Understanding the biology of thermogenic fat: Is browning a new approach to the treatment of obesity? Arch Med Res 48(5):401-413. https://doi.org/10.1016/j.arcmed.2017.10.002 4. Giralt M, Villarroya F (2013) White, brown, beige/brite: Different adipose cells for different functions? Endocrinology 154(9):2992-3000. https://doi.org/10.1210/en.2013-1403 4. Giralt M, Villarroya F (2013) White, brown, beige/brite: Different adipose cells for different functions? Endocrinology 154(9):2992-3000. https://doi.org/10.1210/en.2013-1403 5. Sell H, Deshaies Y, Richard D (2004) The brown adipocyte: update on its metabolic role. Int J Biochem Cell Biol 36(11):2098-2104. https://doi.org/10.1016/j.biocel.2004.04.003 5. Sell H, Deshaies Y, Richard D (2004) The brown adipocyte: update on its metabolic role. Int J Biochem Cell Biol 36(11):2098-2104. https://doi.org/10.1016/j.biocel.2004.04.003 6. Cohen P, Spiegelman BM (2015) Brown and beige fat: molecular parts of a thermogenic machine. Diabetes 64(7):2346-2351. https://doi.org/10.2337/db15-0318 6. Cohen P, Spiegelman BM (2015) Brown and beige fat: molecular parts of a thermogenic machine. Diabetes 64(7):2346-2351. https://doi.org/10.2337/db15-0318 7. Rosen ED, Sarraf P, Troy AE, Bradwin G, Moore K, Milstone DS, Spiegelman BM, Mortensen RM (1999) PPARγ is required for the differentiation of adipose tissue in vivo and in vitro. Molecular Cell 4(4):611-617. https://doi.org/10.1016/S1097-2765(00)80211-7 7. Rosen ED, Sarraf P, Troy AE, Bradwin G, Moore K, Milstone DS, Spiegelman BM, Mortensen RM (1999) PPARγ is required for the differentiation of adipose tissue in vivo and in vitro. Molecular Cell 4(4):611-617. https://doi.org/10.1016/S1097-2765(00)80211-7 8. Ethical approval The collection of adipose tissue samples were approved by the Institutional Animal Care and Use Committee at Nanjing Agricultural University (Permission number: SYXK-2017-0027). The collection of adipose tissue samples were approved by the Institutional Animal Care and Use Committee at Nanjing Agricultural University (Permission number: SYXK-2017-0027) The collection of adipose tissue samples were approved by the Institutional Animal Care and Use The collection of adipose tissue samples were approved by the Institutional Animal Care and Use Committee at Nanjing Agricultural University (Permission number: SYXK-2017-0027). Conflict of interest Page 12/22 The authors declare that they have no conflict of interest. The authors declare that they have no conflict of interest. Page 12/22 Page 12/22 References Kubota N, Terauchi Y, Miki H, Tamemoto H, Yamauchi T, Komeda K, Satoh S, Nakano R, Ishii C, Sugiyama T, Eto K, Tsubamoto Y, Okuno A, Murakami K, Sekihara H, Hasegawa G, Naito M, Toyoshima Y, Tanaka S, Shiota K, Kitamur T, Fujita T, Ezaki O, Aizawa S, Nagai R, Tobe K, Kimura S, Kadowaki T (1999) PPARγ mediates high-fat diet–induced adipocyte hypertrophy and insulin resistance. Molecular Cell 4(4):597-609. https://doi.org/10.1016/s1097-2765(00)80210-5 9. Rosen ED, Hsu CH, Wang X, Sakai S, Freeman MW, Gonzalez FJ, Spiegelman BM (2002) C/EBPα induces adipogenesis through PPARγ: a unified pathway. Genes Dev 16(1):22-26. https://doi.org/10.1101/gad.948702 10. Wang J, Zhang L, Dong L, Hu X, Feng F, Chen F (2019) 6-gingerol, a functional polyphenol of ginger, promotes browning through an AMPK-dependent pathway in 3T3-L1 adipocytes. J Agric Food Chem 67(51):14056-14065. https://doi.org/10.1021/acs.jafc.9b05072 11. Danysz W, Han Y, Li F, Nicoll J, Buch P, Hengl T, Ruitenberg M, Parsons C (2018) Browning of white adipose tissue induced by the β3 agonist CL-316,243 after local and systemic treatment - PK-PD relationship. Biochim Biophys Acta Mol Basis Dis 1864(9):2972-2982. https://doi.org/10.1016/j.bbadis.2018.06.007 Page 13/22 12. Xie S, Li Y, Teng W, Du M, Li Y, Sun B (2019) Liensinine inhibits beige adipocytes recovering to white adipocytes through blocking mitophagy flux in vitro and in vivo. Nutrients 11(7):1640-1654. https://doi.org/10.3390/nu11071640 13. List EO, Palmer AJ, Berryman DE, Bower B, Kelder B, Kopchick JJ (2009) Growth hormone improves body composition, fasting blood glucose, glucose tolerance and liver triacylglycerol in a mouse model of diet-induced obesity and type 2 diabetes. Diabetologia 52(8):1647-1655. https://doi.org/10.1007/s00125-009-1402-z 14. Berryman DE, List EO, Kohn DT, Coschigano KT, Seeley RJ, Kopchick JJ (2006) Effect of growth hormone on susceptibility to diet-induced obesity. Endocrinology 147(6):2801-2808. https://doi.org/10.1210/en.2006-0086 15. Bredella MA, Karastergiou K, Bos SA, Gerweck AV, Torriani M, Fried SK, Miller KK (2017) GH administration decreases subcutaneous abdominal adipocyte size in men with abdominal obesity. Growth Horm IGF Res 35:17-20. https://doi.org/10.1016/j.ghir.2017.06.001 16. List EO, Berryman DE, Buchman M, Jensen EA, Funk K, Duran-Ortiz S, Qian Y, Young JA, Slyby J, McKenna S, Kopchick JJ (2019) GH knockout mice have increased subcutaneous adipose tissue with decreased fibrosis and enhanced insulin sensitivity. Endocrinology 160(7):1743-1756. https://doi.org/10.1210/en.2019-00167 17. References Zvonic S, Story DJ, Stephens JM, Mynatt RL (2003) Growth hormone, but not insulin, activates STAT5 proteins in adipocytes in vitro and in vivo. Biochem Biophys Res Commun 302(2):359-362. https://doi.org/10.1016/s0006-291x(03)00179-7 24. Zvonic S, Story DJ, Stephens JM, Mynatt RL (2003) Growth hormone, but not insulin, activates STAT5 proteins in adipocytes in vitro and in vivo. Biochem Biophys Res Commun 302(2):359-362. https://doi.org/10.1016/s0006-291x(03)00179-7 25. Fain JN, Ihle JH, Bahouth SW (1999) Stimulation of lipolysis but not of leptin release by growth hormone is abolished in adipose tissue from Stat5a and b knockout mice. Biochem Biophys Res Commun 263(1):201-205. https://doi.org/10.1006/bbrc.1999.1302 25. Fain JN, Ihle JH, Bahouth SW (1999) Stimulation of lipolysis but not of leptin release by growth hormone is abolished in adipose tissue from Stat5a and b knockout mice. Biochem Biophys Res Commun 263(1):201-205. https://doi.org/10.1006/bbrc.1999.1302 26. Kaltenecker D, Mueller KM, Benedikt P, Feiler U, Themanns M, Schlederer M, Kenner L, Schweiger M, Haemmerle G, Moriggl R (2017) Adipocyte STAT5 deficiency promotes adiposity and impairs lipid mobilisation in mice. Diabetologia 60(2):296-305. https://doi.org/10.1007/s00125-016-4152-8 27. Liu X, Robinson GW, Wagner KU, Garrett L, Wynshaw-Boris A, Hennighausen L (1997) Stat5a is d t f d lt l d d l t d l t i G D 11(2) 179 186 26. Kaltenecker D, Mueller KM, Benedikt P, Feiler U, Themanns M, Schlederer M, Kenner L, Schweiger M, Haemmerle G, Moriggl R (2017) Adipocyte STAT5 deficiency promotes adiposity and impairs lipid mobilisation in mice. Diabetologia 60(2):296-305. https://doi.org/10.1007/s00125-016-4152-8 27. Liu X, Robinson GW, Wagner KU, Garrett L, Wynshaw-Boris A, Hennighausen L (1997) Stat5a is mandatory for adult mammary gland development and lactogenesis. Genes Dev 11(2):179-186. https://doi.org/10.1101/gad.11.2.179 28. Floyd ZE, Stephens JM (2003) STAT5A promotes adipogenesis in nonprecursor cells and associates with the glucocorticoid receptor during adipocyte differentiation. Diabetes 52(2):308-314. https://doi.org/10.2337/diabetes.52.2.308 29. Gao P, Zhang Y, Liu Y, Chen J, Zong C, Yu C, Cui S, Gao W, Qin D, Sun W, Li X, Wang X (2015) Signal transducer and activator of transcription 5B (STAT5B) modulates adipocyte differentiation via MOF. Cell Signal 27(12):2434-2443. https://doi.org/10.1016/j.cellsig.2015.09.010 30. Livak KJ, Schmittgen TD (2001) Analysis of relative gene expression data using real-time quantitative PCR and the 2(-Delta Delta C(T)) Method. Methods 25(4):402-408. https://doi.org/10.1006/meth.2001.1262 31. Barclay JL, Nelson CN, Ishikawa M, Murray LA, Kerr LM, McPhee TR, Powell EE, Waters MJ (2011) GH-dependent STAT5 signaling plays an important role in hepatic lipid metabolism. Endocrinology 152(1):181-192. https://doi.org/10.1210/en.2010-0537 32. References Comisford R, Lubbers ER, Householder LA, Suer O, Tchkonia T, Kirkland JL, List EO, Kopchick JJ, Berryman DE (2016) Growth hormone receptor antagonist transgenic mice have increased subcutaneous adipose tissue mass, altered glucose homeostasis and no change in white adipose tissue cellular senescence. Gerontology 62(2):163-172. https://doi.org/10.1159/000439050 18. Kawai M, Namba N, Mushiake S, Etani Y, Nishimura R, Makishima M, Ozono K (2007) Growth hormone stimulates adipogenesis of 3T3-L1 cells through activation of the Stat5A/5B-PPARγ pathway. J Mol Endocrinol 38(1-2):19-34. https://doi.org/10.1677/jme.1.02154 19. Xu A, Wong LC, Wang Y, Xu JY, Cooper GJS, Lam KSL (2004) Chronic treatment with growth hormone stimulates adiponectin gene expression in 3T3-L1 adipocytes. FEBS Lett 572(1-3):129-134. https://doi.org/10.1016/j.febslet.2004.07.020 19. Xu A, Wong LC, Wang Y, Xu JY, Cooper GJS, Lam KSL (2004) Chronic treatment with growth hormone stimulates adiponectin gene expression in 3T3-L1 adipocytes. FEBS Lett 572(1-3):129-134. https://doi.org/10.1016/j.febslet.2004.07.020 20. Shang CA, Waters MJ (2003) Constitutively active signal transducer and activator of transcription 5 can replace the requirement for growth hormone in adipogenesis of 3T3-F442A preadipocytes. Mol Endocrinol 17(12):2494-2508. https://doi.org/10.1210/me.2003-0139 20. Shang CA, Waters MJ (2003) Constitutively active signal transducer and activator of transcription 5 can replace the requirement for growth hormone in adipogenesis of 3T3-F442A preadipocytes. Mol Endocrinol 17(12):2494-2508. https://doi.org/10.1210/me.2003-0139 21. Bolamperti S, Signo M, Spinello A, Moro G, Fraschini G, Guidobono F, Rubinacci A, Villa I (2018) GH prevents adipogenic differentiation of mesenchymal stromal stem cells derived from human trabecular bone via canonical Wnt signaling. Bone 112:136-144. https://doi.org/10.1016/j.bone.2018.04.014 21. Bolamperti S, Signo M, Spinello A, Moro G, Fraschini G, Guidobono F, Rubinacci A, Villa I (2018) GH prevents adipogenic differentiation of mesenchymal stromal stem cells derived from human trabecular bone via canonical Wnt signaling. Bone 112:136-144. https://doi.org/10.1016/j.bone.2018.04.014 22. Sharma VM, Vestergaard ET, Jessen N, Kolind-Thomsen P, Nellemann B, Nielsen TS, Vendelbo MH, Møller N, Sharma R, Lee KY, Kopchick JJ, Jørgensen JOL, Puri V (2019) Growth hormone acts along the PPARγ-FSP27 axis to stimulate lipolysis in human adipocytes. Am J Physiol Endocrinol Metab 316(1):E34-E42. https://doi.org/10.1152/ajpendo.00129.2018 Page 14/22 Page 14/22 23. Hioki C, Yoshida T, Kogure A, Takakura Y, Umekawa T, Yoshioka K, Shimatsu A, Yoshikawa T (2004) Effects of growth hormone (GH) on mRNA levels of uncoupling proteins 1, 2, and 3 in brown and white adipose tissues and skeletal muscle in obese mice. Horm Metab Res 36(9):607-613. https://doi.org/10.1055/s-2004-825905 24. References Sharma R, Luong Q, Sharma VM, Harberson M, Harper B, Colborn A, Berryman DE, Jessen N, Jørgensen JOL, Kopchick JJ, Puri V, Lee KY (2018) Growth hormone controls lipolysis by regulation of FSP27 expression. J Endocrinol 239(3):289-301. https://doi.org/10.1530/JOE-18-0282 33. Flint DJ, Binart N, Kopchick J, Kelly P (2003) Effects of growth hormone and prolactin on adipose tissue development and function. Pituitary 6(2):97-102. https://doi.org/10.1023/b:pitu.0000004800.57449.67 34. Kopchick JJ, Berryman DE, Puri V, Lee KY, Jorgensen JOL (2020) The effects of growth hormone on adipose tissue: old observations, new mechanisms. Nat Rev Endocrinol 16(3):135-146. https://doi.org/10.1038/s41574-019-0280-9 Page 15/22 35. Olarescu NC, Berryman DE, Householder LA, Lubbers ER, List EO, Benencia F, Kopchick JJ, Bollerslev J (2015) GH action influences adipogenesis of mouse adipose tissue-derived mesenchymal stem cells. J Endocrinol 226(1):13-23. https://doi.org/10.1530/JOE-15-0012 36. Able AA, Burrell JA, Stephens JM (2017) STAT5-interacting proteins: a synopsis of proteins that regulate STAT5 activity. Biology (Basel) 6(1):20. https://doi.org/10.3390/biology6010020 36. Able AA, Burrell JA, Stephens JM (2017) STAT5-interacting proteins: a synopsis of proteins that regulate STAT5 activity. Biology (Basel) 6(1):20. https://doi.org/10.3390/biology6010020 37. Møller N, Jørgensen JOL (2009) Effects of growth hormone on glucose, lipid, and protein metabolism in human subjects. Endocr Rev 30(2):152-177. https://doi.org/10.1210/er.2008-0027 37. Møller N, Jørgensen JOL (2009) Effects of growth hormone on glucose, lipid, and protein metabolism in human subjects. Endocr Rev 30(2):152-177. https://doi.org/10.1210/er.2008-0027 38. Zhao L, Wang A, Corl BA, Jiang H (2014) Effect of growth hormone on the differentiation of bovine preadipocytes into adipocytes and the role of the signal transducer and activator of transcription 5b. J Anim Sci 92(5):1958-1967. https://doi.org/10.2527/jas.2013-7113 38. Zhao L, Wang A, Corl BA, Jiang H (2014) Effect of growth hormone on the differentiation of bovine preadipocytes into adipocytes and the role of the signal transducer and activator of transcription 5b. J Anim Sci 92(5):1958-1967. https://doi.org/10.2527/jas.2013-7113 39. Tontonoz P, Spiegelman BM (2008) Fat and beyond: the diverse biology of PPARγ. Annu Rev Biochem 77:289-312. https://doi.org/10.1146/annurev.biochem.77.061307.091829 39. Tontonoz P, Spiegelman BM (2008) Fat and beyond: the diverse biology of PPARγ. Annu Rev Biochem 77:289-312. https://doi.org/10.1146/annurev.biochem.77.061307.091829 40. Hagen RM, Rodriguez-Cuenca S, Vidal-Puig A (2010) An allostatic control of membrane lipid composition by SREBP1. FEBS Lett 584(12):2689-2698. https://doi.org/10.1016/j.febslet.2010.04.004 40. Hagen RM, Rodriguez-Cuenca S, Vidal-Puig A (2010) An allostatic control of membrane lipid composition by SREBP1. FEBS Lett 584(12):2689-2698. https://doi.org/10.1016/j.febslet.2010.04.004 41. Paton CM, Ntambi JM (2009) Biochemical and physiological function of stearoyl-CoA desaturase. Am J Physiol Endocrinol Metab 297(1):E28-E37. https://doi.org/10.1152/ajpendo.90897.2008 41. References Paton CM, Ntambi JM (2009) Biochemical and physiological function of stearoyl-CoA desaturase. Am J Physiol Endocrinol Metab 297(1):E28-E37. https://doi.org/10.1152/ajpendo.90897.2008 42. Stewart WC, Baugh Jr. JE, Floyd ZE, Stephens JM (2004) STAT 5 activators can replace the requirement of FBS in the adipogenesis of 3T3-L1 cells. Biochem Biophys Res Commun 324(1):355- 359. https://doi.org/10.1016/j.bbrc.2004.09.053 42. Stewart WC, Baugh Jr. JE, Floyd ZE, Stephens JM (2004) STAT 5 activators can replace the requirement of FBS in the adipogenesis of 3T3-L1 cells. Biochem Biophys Res Commun 324(1):355- 359. https://doi.org/10.1016/j.bbrc.2004.09.053 43. Nelson CN, List EO, Ieremia M, Constantin L, Chhabra Y, Kopchick JJ, Waters MJ (2018) Growth hormone activated STAT5 is required for induction of beige fat in vivo. Growth Horm IGF Res 42- 43:40-51. https://doi.org/10.1016/j.ghir.2018.08.004 43. Nelson CN, List EO, Ieremia M, Constantin L, Chhabra Y, Kopchick JJ, Waters MJ (2018) Growth hormone activated STAT5 is required for induction of beige fat in vivo. Growth Horm IGF Res 42- 43:40-51. https://doi.org/10.1016/j.ghir.2018.08.004 44. Keipert S, Jastroch M (2014) Brite/beige fat and UCP1 - is it thermogenesis? Biochim Biophys Acta 1837(7):1075-1082. https://doi.org/10.1016/j.bbabio.2014.02.008 44. Keipert S, Jastroch M (2014) Brite/beige fat and UCP1 - is it thermogenesis? Biochim Biophys Acta 1837(7):1075-1082. https://doi.org/10.1016/j.bbabio.2014.02.008 45. Hayashi M, Futawaka K, Koyama R, Fan Y, Matsushita M, Hirao A, Fukuda Y, Nushida A, Nezu S, Tagami T, Moriyama K (2017) Effects of growth hormone on uncoupling protein 1 in white adipose tissues in obese mice. Growth Horm IGF Res 37:31-39. https://doi.org/10.1016/j.ghir.2017.10.006 46. Mooli RGR, Mukhi D, Watt M, Edmunds L, Xie B, Capooci J, Reslink M, Eze C, Mills A, Stolz DB, Jurczak M, Ramakrishnan SK (2020) Sustained mitochondrial biogenesis is essential to maintain caloric restriction-induced beige adipocytes. Metabolism 107:154225. https://doi.org/10.1016/j.metabol.2020.154225 47. Wood Dos Santos T, Cristina Pereira Q, Teixeira L, Gambero A, Villena JA, Lima Ribeiro M (2018) Effects of polyphenols on thermogenesis and mitochondrial biogenesis. Int J Mol Sci 19(9):2757. https://doi.org/10.3390/ijms19092757 47. Wood Dos Santos T, Cristina Pereira Q, Teixeira L, Gambero A, Villena JA, Lima Ribeiro M (2018) Effects of polyphenols on thermogenesis and mitochondrial biogenesis. Int J Mol Sci 19(9):2757. https://doi.org/10.3390/ijms19092757 48. Cardanho-Ramos C, Morais VA (2021) Mitochondrial biogenesis in neurons: how and where. Int J Mol Sci 22(23):13059. https://doi.org/10.3390/ijms222313059 48. Cardanho-Ramos C, Morais VA (2021) Mitochondrial biogenesis in neurons: how and where. Int J Mol Sci 22(23):13059. https://doi.org/10.3390/ijms222313059 Page 16/22 49. References Clasen BF, Poulsen MM, Escande C, Pedersen SB, Møller N, Chini EN, Jessen N, Jørgensen JOL (2014) Growth hormone signaling in muscle and adipose tissue of obese human subjects: associations with measures of body composition and interaction with resveratrol treatment. J Clin Endocrinol Metab 99(12):E2565-E2573. https://doi.org/10.1210/jc.2014-2215 50. Richard AJ, Stephens JM (2014) The role of JAK-STAT signaling in adipose tissue function. Biochim Biophys Acta 1842(3):431-439. https://doi.org/10.1016/j.bbadis.2013.05.030 51. Kaltenecker D, Spirk K, Ruge F, Grebien F, Herling M, Rupprecht A, Kenner L, Pohl EE, Mueller KM, Moriggl R (2020) STAT5 is required for lipid breakdown and beta-adrenergic responsiveness of brown adipose tissue. Mol Metab 40:101026. https://doi.org/10.1016/j.molmet.2020.101026 52. Farrar MA, Heltemes-Harris LM (2011) Turning transcription on or off with STAT5: when more is less. Nat Immunol 12(12):1139-1140. https://doi.org/10.1038/ni.2163 52. Farrar MA, Heltemes-Harris LM (2011) Turning transcription on or off with STAT5: when more is less. Nat Immunol 12(12):1139-1140. https://doi.org/10.1038/ni.2163 53. Poudel SB, Dixit M, Neginskaya M, Nagaraj K, Pavlov E, Werner H, Yakar S (2020) Effects of GH/IGF on the aging mitochondria. Cells 9(6):1384. https://doi.org/10.3390/cells9061384 Figures Page 17/22 Page 18/22 Figure 1 GH inhibited the differentiation of bovine subcutaneous preadipocytes. a Cell viability of bovine subcutaneous preadipocytes treated with different concentrations (10, 100, 500 ng/mL) of GH for 48 h. b GH treatment (10, 100, 500 ng/mL) during the adipogenic differentiation program. c Oil red O staining of bovine subcutaneous adipocytes on day 8 after treatment with various concentrations of GH. Magnification, 200x and 100x. Scale bars, 50 µm and 100 µm. d The result of oil red O extraction. e The Figure 1 GH inhibited the differentiation of bovine subcutaneous preadipocytes. a Cell viability of bovine subcutaneous preadipocytes treated with different concentrations (10, 100, 500 ng/mL) of GH for 48 h. b GH treatment (10, 100, 500 ng/mL) during the adipogenic differentiation program. c Oil red O staining of bovine subcutaneous adipocytes on day 8 after treatment with various concentrations of GH. Magnification, 200x and 100x. Scale bars, 50 µm and 100 µm. d The result of oil red O extraction. e The Figure 1 GH inhibited the differentiation of bovine subcutaneous preadipocytes. a Cell viability of bovine subcutaneous preadipocytes treated with different concentrations (10, 100, 500 ng/mL) of GH for 48 h. b GH treatment (10, 100, 500 ng/mL) during the adipogenic differentiation program. c Oil red O staining of bovine subcutaneous adipocytes on day 8 after treatment with various concentrations of GH. Magnification, 200x and 100x. Scale bars, 50 µm and 100 µm. d The result of oil red O extraction. e The Page 18/22 Page 18/22 expression levels of adipogenic key genes was detected by RT-qPCR in adipocytes after GH treatment for 8 days. Data are presented as means ± SEM (n = 4). *P < 0.05, **P < 0.01 vs. the 0 ng/mL group. ( ) Page 19/22 Figure 2 GH strongly suppressed the differentiation of bovine subcutaneous adipocytes at the early stage of differentiation. a Adipocytes were treated with GH (500 ng/mL) at the indicated time point during the differentiated process. b Oil red O staining of differentiated bovine subcutaneous adipocytes. Figure 2 Figure 2 GH strongly suppressed the differentiation of bovine subcutaneous adipocytes at the early stage of differentiation. a Adipocytes were treated with GH (500 ng/mL) at the indicated time point during the differentiated process. b Oil red O staining of differentiated bovine subcutaneous adipocytes. Page 19/22 Page 19/22 Page 19/22 Magnification, 200x and 100x. Scale bars, 50 µm and 100 µm. c The content of oil red O extraction. d, e GH-treated adipocytes were collected for RT-qPCR analysis at 1 and 2 days of differentiation. f Western blot analysis of PPARγ at 1 and 2 days of differentiation. Data are presented as means ± SEM (n = 4). *P < 0.05, **P < 0.01 vs. the control group. Magnification, 200x and 100x. Scale bars, 50 µm and 100 µm. c The content of oil red O extraction. d, e GH-treated adipocytes were collected for RT-qPCR analysis at 1 and 2 days of differentiation. f Western blot analysis of PPARγ at 1 and 2 days of differentiation. Data are presented as means ± SEM (n = 4). *P < 0.05, **P < 0.01 vs. the control group. < 0.05, P < 0.01 vs. the control group. Figure 3 GH promoted the browning and mitochondrial biogenesis of bovine subcutaneous adipocytes. a The expression level of UCP1 gene in full differentiated adipocytes treated with 500 ng/mL GH for the indicated times. b After 6 h of GH treatment, the expression of browning-related genes was analyzed by RT-qPCR. c Mitochondrial DNA content quantification by RT-qPCR. d Mature bovine subcutaneous adipocytes were stained with MitoTracker red. Magnification, 200x. Scale bars, 50 µm. e The mRNA expression of TFAM, NRF1, and NRF2 genes in mature bovine subcutaneous adipocytes treated with 500 g p Figure 3 Figure 3 GH promoted the browning and mitochondrial biogenesis of bovine subcutaneous adipocytes. a The expression level of UCP1 gene in full differentiated adipocytes treated with 500 ng/mL GH for the indicated times. b After 6 h of GH treatment, the expression of browning-related genes was analyzed by RT-qPCR. c Mitochondrial DNA content quantification by RT-qPCR. d Mature bovine subcutaneous adipocytes were stained with MitoTracker red. Magnification, 200x. Scale bars, 50 µm. e The mRNA expression of TFAM, NRF1, and NRF2 genes in mature bovine subcutaneous adipocytes treated with 500 ng/mL GH for 6 h. Data are presented as means ± SEM (n = 3). *P < 0.05, **P < 0.01 vs. Figure 2 the control group. Page 20/22 Figure 4 GH increased the phosphorylation of STAT5B in bovine subcutaneous adipocytes. a Western blot analysis of p-STAT5B and STAT5B at day 0 of adipocyte differentiation with GH (500 ng/mL) treatment for 10, 30, 60, and 180 minutes. b Western blot analysis of p-STAT5B and STAT5B in mature adipocytes f ( ) f d h f d fl Figure 4 GH increased the phosphorylation of STAT5B in bovine subcutaneous adipocytes. a Western blot analysis of p-STAT5B and STAT5B at day 0 of adipocyte differentiation with GH (500 ng/mL) treatment for 10, 30, 60, and 180 minutes. b Western blot analysis of p-STAT5B and STAT5B in mature adipocytes after GH (500 ng/mL) treatment for 1 and 6 hours. c Images of adipocytes STAT5B immunofluorescent staining after GH (500 ng/mL) treatment for 60 min. Magnification, 200x. Scale bars, 50 µm. Data are presented as means ± SEM (n = 4). *P < 0.05, **P < 0.01 vs. the control group. Figure 4 GH increased the phosphorylation of STAT5B in bovine subcutaneous adipocytes. a Western blot analysis of p-STAT5B and STAT5B at day 0 of adipocyte differentiation with GH (500 ng/mL) treatment for 10, 30, 60, and 180 minutes. b Western blot analysis of p-STAT5B and STAT5B in mature adipocytes after GH (500 ng/mL) treatment for 1 and 6 hours. c Images of adipocytes STAT5B immunofluorescent staining after GH (500 ng/mL) treatment for 60 min. Magnification, 200x. Scale bars, 50 µm. Data are presented as means ± SEM (n = 4). *P < 0.05, **P < 0.01 vs. the control group. Page 21/22 Figure 5 GH-induced differentiation and browning of bovine subcutaneous adipocytes were mediated by STAT5B. a Adipocytes were preincubated with STAT5-IN-1 (100 μM) for 1 h and treated with GH (500 ng/mL) for 1 h during the differentiated process (day 0). Western blot was used to analyze the expression of p- STAT5B and STAT5B proteins (n = 4). b Adipocytes were preincubated with STAT5-IN-1 (100 μM) for 1 h and treated with GH (500 ng/mL) for 24 h during the differentiated process (day 0). RT-qPCR was used to analyze the expression of PPARγ, CEBPα, and SREBP1 genes (n = 3). c Mature adipocytes were preincubated with STAT5-IN-1 (100μM) for 1 h and treated with GH (500 ng/mL) for 6 h. Figure 2 RT-qPCR was used to analyze the expression levels of UCP1, PGC-1α, and PRDM16 genes (n = 3). Data are presented as means ± SEM. Statistical significance shows as *P < 0.05, **P < 0.01. Figure 5 Figure 5 GH-induced differentiation and browning of bovine subcutaneous adipocytes were mediated by STAT5B. a Adipocytes were preincubated with STAT5-IN-1 (100 μM) for 1 h and treated with GH (500 ng/mL) for 1 h during the differentiated process (day 0). Western blot was used to analyze the expression of p- STAT5B and STAT5B proteins (n = 4). b Adipocytes were preincubated with STAT5-IN-1 (100 μM) for 1 h and treated with GH (500 ng/mL) for 24 h during the differentiated process (day 0). RT-qPCR was used to analyze the expression of PPARγ, CEBPα, and SREBP1 genes (n = 3). c Mature adipocytes were preincubated with STAT5-IN-1 (100μM) for 1 h and treated with GH (500 ng/mL) for 6 h. RT-qPCR was used to analyze the expression levels of UCP1, PGC-1α, and PRDM16 genes (n = 3). Data are presented as means ± SEM. Statistical significance shows as *P < 0.05, **P < 0.01. Page 22/22
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3,434
ХИРУРГИЯ ХИРУРГИЯ © ПЕТУХОВ А.В., 2016 © ПЕТУХОВ А.В., 2016 ПЕТУХОВ А.В. УО «Витебский государственный ордена Дружбы народов медицинский университет», г.Витебск, Республика Беларусь Вестник ВГМУ. – 2016. – Том 15, №2. – С. 60-66. Резюме. Цель – оценить степень алиментарного истощения и биохимических нарушений, а также результаты при- менения баллонной дилятации у пациентов со стриктурами пищевода, путем оценки качества жизни. Материал и методы. В исследование включены 36 пациентов с послеожоговыми стриктурами пищевода, которым была произведена баллонная дилятация. У всех пациентов определялся индекс массы тела, опре- делялся уровень основных биохимических параметров крови, уровень гемоглобина, эритроцитов, а также степень дисфагии. Диагноз сриктуры пищевода у всех пациентов подтвержден рентгенологически и эндо- скопически. После проведенного лечения проводилось исследование качества жизни с помощью опросни- ка SF-36. Результаты. Установлено, что у 88,9% пациентов имеется дисфагия 3 степени, 69,4% пациентов имеют де- фицит массы тела. При этом грубых лабораторных изменений, таких как гипопротеинемия, гипоальбуми- немия, снижение уровня гемоглобина, эритроцитов не отмечается. Применение баллонной дилятации по- зволяет безопасно и эффективно восстановить просвет пищевода, при этом требуется от 1 до 3 процедур с интервалом в 1-2 дня. При исследовании качества жизни выявлено, что более других страдают показатели: общего здоровья, ролевого и эмоционального функционирования. А при расчете общих показателей более страдает «психологический компонент здоровья» – 40,15 балла по сравнению с «физическим компонентом здоровья», который составил 49,61 балла. Заключение. Основными показателями тяжести состояния пациентов с послеожоговыми стриктурами пи- щевода являются индекс массы тела и дисфагия. Баллонная дилятация является эффективным и безопас- ным методом восстановления проходимости пищевода. Снижение качества жизни пациентов с послеожо- говыми стриктурами происходит в основном за счет психологического компонента здоровья. Ключевые слова: стриктура пищевода, баллонная дилятация пищевода, качество жизни. PETUKHOV A.V. Educational Establishment «Vitebsk State Order of Peoples’ Friendship Medical University», Vitebsk, Republic of Belarus Vestnik VGMU. 2016;15(2):60-66. Abstract. Objectives. To assess the degree of alimentary inanition and biochemical disturbances as well as the life quality of patients with esophageal strictures after chemical burns following balloon dilatation. Material and methods. The total of 36 cases with esophageal burns strictures were treated with balloon dilatation. In all patients their body mass index, the level of the main biochemical parameters of the blood, the level of hemoglobin, erythrocytes as well as the degree of dysphagia were determined. The diagnosis of esophageal stricture was confirmed using both upper endoscopy and contrast radiography of the upper gastrointestinal tract. After the provided treatment the quality of life was estimated using SF-36 questionnaire. p q y g q Results. The third degree dysphagia was registered in 88,9% of patients and 69,4% of them were underweight. There were no gross deviations in blood analysis such as hypoproteinemia, hypoalbuminemia or decrease in the 60 ВЕСТНИК ВГМУ, 2016, ТОМ 15, №2 amount of red blood cells or hemoglobin. Esophageal balloon dilatation allows to safely and effectively restore luminal diameter of the esophagus requiring only 1 to 3 procedures with 1-2 days interval. The quality of life analysis has shown that such indices as general health, emotional health and role functioning are affected most of all. And when calculating general indices the «psychological component of health» suffers more – 40,15 points in comparison with the «physical component of health», which made up 49,61 points. p p y p p p Conclusions. The main indicators of the severity of patients’ condition with post-burn esophageal strictures are body mass index and dysphagia degree. Esophageal balloon dilatation is a safe and effective way to restore luminal diameter of the esophagus thus relieving dysphagia. The reduction of the life quality in patients with post-burn strictures occurs mainly due to the psychological health component. y p y g p Key words: esophageal stricture, esophageal balloon dilatation, quality of life. В настоящее время в доступной литера- туре имеется мало данных о частоте развития рубцовых стриктур пищевода, а также о совре- менных методах их лечения. Чаще всего в ка- честве основного метода лечения указывается бужирование пищевода [1]. Применение других методов лечения стриктур пищевода, в том чис- ле баллонной дилятации, в отечественной лите- ратуре практически не освещено [2]. Так, А.Ф. Черноусов и соавт. [3] упоминают об эндоско- пической баллонной гидростатической дилята- ции, однако в основном описывается методика различных вариантов бужирования. Abstract. В зарубеж- ной литературе встречаются сообщения о диля- тации пищевода в качестве дополнительного метода при паллиативном лечении рака пище- вода [4]. По данным Галлингер Ю.И., Годжел- ло Э.А. (1999), при коротких стриктурах пище- вода (до 5 см.) стойкого выздоровления после баллонной дилятации удается добиться в 85-90 % случаев [5]. В то же время, количество паци- ентов с данной патологией из года в год увели- чивается, что является основанием для более глубокого изучения проблемы. Материал и методы В исследования включены 36 пациентов с послеожоговыми стриктурами пищевода, которым была произведена баллонная диля- тация. Средний возраст 53,23±17,15 лет. Муж- чин было 22, женщин – 14 (61% и 39% соответ- ственно). Из анамнеза известно, что у 80,6% паци- ентов причиной развития рубцовых стенозов пищевода явилось употребление прижигаю- щей жидкости. Длительность заболевания ко- лебалась от 7 месяцев до 5,5 лет, среднее значе- ние составило 18,36±15,7 месяцев. Все пациенты отмечали снижение массы тела в большей или меньшей степени. Для объ- ективной оценки этого показателя нами иссле- дован индекс массы тела (ИМТ), который рас- считывали по формуле 1: считывали по формуле 1: (1) ф р у ИМТ=М/Р2, (1) где М – масса в кг, Р – рост в метрах. ф р у ИМТ=М/Р2, (1) где М – масса в кг, Р – рост в метрах. (1) Для оценки использовали общеприня- тую шкалу (табл. 1). Все пациенты обследованы лаборатор- ными и инструментальными методами. При лабораторных исследованиях обращали вни- мание на уровень гемоглобина, эритроцитов, а также на уровень основных биохимических Цель – оценить степень алиментарно- го истощения и биохимических нарушений, а также результаты применения баллонной ди- лятации у пациентов со стриктурами пищево- да, путем оценки качества жизни. Таблица 1 – Индекс массы тела ИМТ Оценка 16 и менее Выраженный дефицит массы тела 16-18,5 Недостаточная (дефицит) масса тела 18,5-24,99 Норма 25-30 Избыточная масса тела (предожирение) 30-35 Ожирение первой степени 35-40 Ожирение второй степени 40 и более Ожирение третьей степени (морбидное) 61 БАЛЛОННАЯ ДИЛЯТАЦИЯ И КАЧЕСТВО ЖИЗНИ параметров: АЛТ, АСТ, глюкоза, билирубин общий, билирубин прямой, мочевина, креати- нин, общий белок, альбумины, глобулины. параметров: АЛТ, АСТ, глюкоза, билирубин общий, билирубин прямой, мочевина, креати- нин, общий белок, альбумины, глобулины. индекса массы тела были получены следующие данные. Пациентов с ожирением 1, 2 и 3 степе- ни не было. У 3-х (8,33%) пациентов выявлено наличие избыточной массы тела (ИМТ 25-30). Нормальное значение ИМТ определено у 15 (41,67%) пациентов. 17 (47,2%) пациентов име- ли дефицит массы тела (ИМТ от 16 до 18), и у 1 (2,8%) пациента диагностирован выраженный дефицит массы тела (ИМТ 15,37). Наличие па- циентов с избыточной массой тела и нормаль- ными значениями ИМТ объясняется коротким анамнезом заболевания у данной группы, т.е. чем длительнее анамнез, тем более снижаются показатели ИМТ. Из инструментальных методов обяза- тельно проводилась фиброэзофагоскопия и рентгеноскопия пищевода. Исследование качества жизни осущест- влялось с применением опросника качества жизни SF-36 [6]. В опроснике выделено 8 шкал, по которым и оценивается качество жизни. 8. Психологическое здоровье (MH). Оценка результатов производилась пу- тем суммирования баллов согласно каждой шкале с последующим расчетом конкретного показателя по формуле 2: Основные биохимические показатели крови у мужчин и женщин представлены в та- блице 2. [ (реальное значение показателя) – (ми- нимально возможное значение показателя) ] : (возможный диапазон значений) * 100 (2) Из таблицы следует, что, вопреки ожи- даниям, грубых биохимических нарушений у пациентов с рубцовыми стриктурами не зави- симо от стажа заболевания не было. Это сви- детельствует о достаточной степени компен- сации организма в условиях ограниченного питания. При фиброэзофагоскопии явления эзофагита выявлены у 14 пациентов (38,9%). (возможный диапазон значений) 100 (2) Опрос пациентов производился путем почтовой рассылки анкет, а также путем анке- тирования пациентов при повторной госпита- лизации для очередного курса лечения. Всего разослано 30 анкет, получено 12 ответов, из них 1 анкета не доставлена адресату вслед- ствие смены места жительства, по данным еще одной анкеты пациент скончался, причина смерти родственниками не указана. Обработ- ке подверглись 10 анкет, полученных по по- чте, и 6 анкет, заполненных пациентами при повторной госпитализации. Таким образом, ответы получены от 44,4% респондентов. Об- работка материала проводилась с помощью пакета программ MSExcel 2007 и Statistica 6.0. Опрос пациентов производился путем почтовой рассылки анкет, а также путем анке- тирования пациентов при повторной госпита- лизации для очередного курса лечения. Всего разослано 30 анкет, получено 12 ответов, из них 1 анкета не доставлена адресату вслед- ствие смены места жительства, по данным еще одной анкеты пациент скончался, причина смерти родственниками не указана. Обработ- ке подверглись 10 анкет, полученных по по- чте, и 6 анкет, заполненных пациентами при повторной госпитализации. Таким образом, ответы получены от 44,4% респондентов. Об- работка материала проводилась с помощью пакета программ MSExcel 2007 и Statistica 6.0. При рентгенологическом исследовании пищевода и желудка был подтвержден топи- ческий диагноз патологического процесса (рис. 1), а также у двух пациентов выявлены признаки рубцовой деформации желудка с на- рушением эвакуаторной функции, у одного – признаки аксиальной грыжи пищеводного отверстия диафрагмы. Следует отметить, что такую характеристику, как протяженность стриктуры можно оценить только по данным рентгеноскопии пищевода. Материал и методы Чем ниже уровень показателя, тем ниже каче- ство жизни. Опросник SF – 36 включает следу- ющие шкалы: 1. Физическое функционирование (PF). 2. Ролевое (физическое) функционирова- ние (RР). При оценке анализов крови выявлено, что у мужчин показатели количества эритро- цитов и лейкоцитов были в пределах нормы (4,62±0,42*1012/л и 8,65±3,1*109/л соответствен- но), а уровень гемоглобина умеренно снижен (131,9±19,5 г/л), у женщин картина аналогич- ная: количество эритроцитов и лейкоцитов в пределах физиологической нормы, гемо- глобин – умеренно снижен (4,21±0,69*1012/л, 7,5±2,7*109/л и 108,4±31,6 г/л соответственно). 3. Боль (P). 4. Общее здоровье (GH). 5. Жизнеспособность (VT). 6. Социальное функционирование (SF). 7. Эмоциональное функционирование (RE). Результаты и обсуждение Кроме локализации стриктуры, оцени- вали оставшийся просвет пищевода. При этом выявлено, что при 3 степени дисфагии просвет, как правило, не превышал 5 мм. При дисфагии 2 степени просвет составлял 5-8 мм. При дисфагии 4 степени просвет пищевода был менее 2 мм. Основной жалобой всех пациентов была дисфагия. Дисфагия 2 степени выявлена у 3 па- циентов, 3 степени – у 32 пациентов, 4 степени – у 1 пациента. При исследовании показателей 62 ВЕСТНИК ВГМУ, 2016, ТОМ 15, №2 Таблица 2 – Биохимические показатели пациентов со стриктурами пищевода. Мужчины (n=22) M±SD Женщины (n=14) M±SD Норма АЛТ 35,1±28,3 26,4±15,2 28-178 АСТ 40,4±24,9 35,5±17,2 28-129 Глюкоза, ммоль/л 4,5±0,8 5,2±2,0 3,3-6,1 Билирубин общий, ммоль/л 13,4±4,2 12,9±3,4 8,5-20,5 Билирубин прямой, ммоль/л 2,8±0,6 3,1±1,4 менее 5,0 Мочевина, ммоль/л 4,2±1,9 4,6±1,8 менее 8,33 Креатинин, ммоль/л 0,104±0,14 0,102±0,12 менее 0,106 Общий белок, г/л 65,8±6,1 67,2±8,3 65-85 Альбумин, г/л 39,8±6,1 37,3±6,6 35-50 Глобулин, г/л 25,3±7,1 30,9±6,1 25-45 2 14 18 1 1 верхняя треть средняя треть нижняя треть верхняя + средняя треть верхняя + нижняя треть Рисунок 1 – Локализация стриктур. Таблица 2 – Биохимические показатели пациентов со стриктурами пищевода. Мужчины (n=22) M±SD Женщины (n=14) M±SD Норма АЛТ 35,1±28,3 26,4±15,2 28-178 АСТ 40,4±24,9 35,5±17,2 28-129 Глюкоза, ммоль/л 4,5±0,8 5,2±2,0 3,3-6,1 Билирубин общий, ммоль/л 13,4±4,2 12,9±3,4 8,5-20,5 Билирубин прямой, ммоль/л 2,8±0,6 3,1±1,4 менее 5,0 Мочевина, ммоль/л 4,2±1,9 4,6±1,8 менее 8,33 Креатинин, ммоль/л 0,104±0,14 0,102±0,12 менее 0,106 Общий белок, г/л 65,8±6,1 67,2±8,3 65-85 Альбумин, г/л 39,8±6,1 37,3±6,6 35-50 Глобулин, г/л 25,3±7,1 30,9±6,1 25-45 Таблица 2 – Биохимические показатели пациентов со стриктурами пищевода. 2 14 18 1 1 верхняя треть средняя треть нижняя треть верхняя + средняя треть верхняя + нижняя треть Рисунок 1 – Локализация стриктур. Рисунок 1 – Локализация стриктур. В клинике госпитальной хирургии ВГМУ на базе торакального отделения с 2010 года в качестве метода лечения рубцовых стриктур используется баллонная дилятация пищево- да. Причем, если в 2010 году таких пациентов было 4, то в 2011 – 9, в 2012 – 17, в 2013 – 17, при этом часть из них была госпитализирова- на повторно для проведения очередного курса лечения. Баллонная дилятация пищевода про- водилась под рентгеновским либо под видео- эндоскопическим контролем. В первом случае пациент укладывается на спину, под рентген- контролем в пищевод вводился контрастный катетер, а затем в просвет пищевода и желуд- ка вводился проводник. Необходимость при- менения катетера была продиктована тем, что проводник с гибким концом цепляется за структуры гортанно-глотки, загибается и не проходит в просвет стриктуры. Результаты и обсуждение После того, как проводник заведен в желудок, по нему производится введение дилятатора. При рент- геновском контроле баллон заводился ниже стриктуры, присоединялся шприц высоко- го давления, заполненный водорастворимым контрастом, при этом баллон раскрывается без дополнительного усилия. Затем баллон про- двигался проксимально до момента появления упругого сопротивления, т.е. места нахожде- ния стриктуры. При этом следует уменьшить наполнение баллона до того уровня, чтобы он прошел через зону стриктуры. Для профилак- тики миграции баллона во время процедуры дистально или проксимально баллон следует устанавливать так, чтобы стриктура распо- лагалась на его середине (рис. 2). Следующим этапом баллон сначала наполнялся мягко (без дополнительного усилия), затем, убедившись, что баллон стоит точно в зоне стриктуры, с по- мощью шприца высокого давления, в баллоне постепенно давление повышались с шагом 0,5 63 БАЛЛОННАЯ ДИЛЯТАЦИЯ И КАЧЕСТВО ЖИЗНИ Рисунок 2 – Баллон в зоне стриктуры. Рисунок 3 – Баллон полностью раскрыт. Рисунок 2 – Баллон в зоне стриктуры. Рисунок 3 – Баллон полностью раскрыт. При проведении процедуры под видеоэ- зофагоскопией, пациент укладывался, как при ФГДС, на левый бок. Под видеоконтролем в просвет пищевода через канал эндоскопа вво- дился проводник, а по проводнику баллон, затем баллон раскрывался в стриктуре. Ди- лятация проводилась аналогично описанной ранее. АТМ, между шагами делались паузы в 30-60 секунд. При этом на манометре обычно отме- чалось плавное снижение давления, что свиде- тельствует о постепенном разрыве рубцовой ткани в зоне стриктуры. Давление постепенно доводилось до максимальных значений, ука- занных на баллоне, т.к. в противном случае раскрытие могло быть неполным. Полностью раскрытый баллон оставляли еще на 5 минут с целью гемостаза (рис. 3). Баллон извлекался в расправленном состоянии, что позволяет до- полнительно диагностировать вышележащие стриктуры. Резкое снижение давления в балло- не может говорить о разрыве баллона, разрыве пищевода или разрыве «толстой» стриктуры. При разрыве баллона при рентген-контроле наблюдается вытекание контраста за пределы баллона. После процедуры обязательно про- водилась контрольная рентгеноскопия пище- вода с водорастворимым контрастом, которая позволяет оценить проходимость пищевода после баллонной дилятации, а также исклю- чить затекание контраста за пределы пищево- да. При необходимости производилась виде- оэзофагоскопия, компьютерная томография грудной клетки. Проведение баллонной дилятации под контролем видеоэзофагоскопии имеет как пре- имущества, так и недостатки. Главное преиму- щество заключается в более быстром и более точном проведении проводника по суженому просвету пищевода в желудок, точная установ- ка баллона в области стриктуры, возможность эндоскопического контроля как проведения самой процедуры, так и непосредственного результата дилятации. Результаты и обсуждение К недостаткам следу- ет отнести невозможность одномоментной дилятации протяженных или множественных стриктур, вследствие чего лечебный эффект может наступить не сразу. Курс лечения составлял от 1 до 3 проце- дур с интервалом в 1-2 дня. Несколько проце- дур проводилось при протяженных стриктурах и стриктурах с минимальным изначальным ди- 64 ВЕСТНИК ВГМУ, 2016, ТОМ 15, №2 и дефицит массы тела, а основные биохимиче- ские показатели крови диагностического зна- чения не имеют. аметром просвета. В таких случаях при первой процедуре дилятация проводилась баллоном меньшего диаметра (6-8 мм), диаметр которо- го при последующих процедурах постепенно доводился до 12-15 мм, что было обусловлено необходимостью видеоэндоскопического кон- троля как зоны дилятяции, так и осмотра же- лудка с целью выявления химического ожога последнего со стенозированием. аметром просвета. В таких случаях при первой процедуре дилятация проводилась баллоном меньшего диаметра (6-8 мм), диаметр которо- го при последующих процедурах постепенно доводился до 12-15 мм, что было обусловлено необходимостью видеоэндоскопического кон- троля как зоны дилятяции, так и осмотра же- лудка с целью выявления химического ожога последнего со стенозированием. 2. Наиболее частой причиной развития стриктуры пищевода у 80,56% пациентов яв- ляется употребление прижигающей жидкости. 3. Баллонная дилятация является эф- фективным и безопасным методом восстанов- ления проходимости пищевода, однако, для достижения стойкого эффекта необходим ре- гулярный контроль (не реже 2 раз в год) с про- ведением повторной баллонной дилятации, при необходимости. 19 пациентам баллонная дилятация пи- щевода проводилась в один этап, 13 паци- ентов были госпитализированы дважды для проведения баллонной дилятации, 1 пациент – трижды и 1 пациент за время наблюдения был госпитализирован 4 раза. 4. У пациентов с послеожоговыми стрик- турами пищевода, в наибольшей степени стра- дает психологический компонент здоровья, менее – физический компонент здоровья. При исследовании качества жизни с по- мощью опросника SF-36, получены следую- щие результаты, представленные в таблице 3. 5. Послеожоговые стриктуры пище- вода являются не только физиологической проблемой, но и откладывают отпечаток на социальное и психологическое благополу- чие пациентов, поэтому лечение их требуют комплексного подхода – лечения патологии пищевода и коррекции психологического со- стояния. р у , р Из таблицы следует, что меньше всего страдают такие показатели как физическое функционирование и показатель боли, что говорит об удовлетворительной компенсации питания в результате проводимой баллонной дилятации. Умеренно снижены показатели жизнеспособности, социального функциони- рования и психологического здоровья. Более всего снижены показатели общего здоровья, ролевого и эмоционального функционирова- ния, что является отражением необходимости соблюдать определенную диету, в первую оче- редь для компенсации имеющейся дисфагии. Литература 1. Черноусов, А. Ф. Пластика пищевода при раке и до- брокачественных стриктурах / А. Ф. Черноусов, В. С. Сильвестров, Ф. С. Курбанов. – М. : Медицина, 1990. – 114 с. 2. Сотников, А. В. Вибрационные и эндохирургические способы расширения рубцовых сужений пищевода / А. В. Сотников // 2-й Московский Международный конгрес по эндоскопической хирургии, 23–25 апр. 1997 г. : сб. тез. – М., 1997. – С. 334–335. 3. Черноусов, А. Ф. Хирургия пищевода : рук. для вра- чей / А. Ф. Черноусов, П. М. Богопольский, Ф. С. Курбанов. – М. : Медицина, 2000. – 352 с. По нашим наблюдениям, даже при хо- роших результатах баллонной дилятации пи- щевода, восстановления исходной массы тела пациентов не происходит на протяжении всего времени наблюдения. 4. Malignant esophagogastric junction obstruction: efficacy of balloon dilation combined with chemotherapy and/or radiation therapy / G.Y. Ko [et al.] // Cardiovasc. Intervent. Radiol. – 2003 Mar-Apr. – Vol. 26, N 2. – P. 141–145. 5. Галлингер, Ю. И. Оперативная эндоскопия пищево- да / Ю. И. Галлингер, Э. А. Годжелло. – М., 1999. – 273 с. Результаты и обсуждение Эти же данные подтверждаются при расчете общих показателей «Физический компонент здоровья» и «Психологический компонент здоровья» выявлено, что первый составляет 49,61 балла против 40,15 балла. БАЛЛОННАЯ ДИЛЯТАЦИЯ И КАЧЕСТВО ЖИЗНИ БАЛЛОННАЯ ДИЛЯТАЦИЯ И КАЧЕСТВО ЖИЗНИ Заключение 1. Основными показателями тяжести со- стояния пациентов с послеожоговыми стрик- турами пищевода являются степень дисфагии 6. Оценка качества жизни больного в медицине / А. А. Новик [и др.] // Клинич. медицина. – 2000. – № 2. – С. 10–13. Поступила 26.02.2016 г. Принята в печать 15.04.2016 г. Поступила 26.02.2016 г. Принята в печать 15.04.2016 г. Поступила 26.02.2016 г. Принята в печать 15.04.2016 г. 65 4. Ko GY, Song HY, Hong HJ, Sung KB, Seo TS, Yoon HK. Malignant esophagogastric junction obstruction: efficacy of balloon dilation combined with chemotherapy and/or radiation therapy. Cardiovasc Intervent Radiol. 2003 Mar-Apr;26(2):141-5. References р 4. Ko GY, Song HY, Hong HJ, Sung KB, Seo TS, Yoon HK. Malignant esophagogastric junction obstruction: efficacy of balloon dilation combined with chemotherapy and/or radiation therapy. Cardiovasc Intervent Radiol. 2003 Mar-Apr;26(2):141-5. 4. Ko GY, Song HY, Hong HJ, Sung KB, Seo TS, Yoon HK. Malignant esophagogastric junction obstruction: efficacy of balloon dilation combined with chemotherapy and/or radiation therapy. Cardiovasc Intervent Radiol. 2003 Mar-Apr;26(2):141-5. 1. Chernousov AF, Silvestrov VS, Kurbanov FS. Plastika pishchevoda pri rake i dobrokachestvennykh strikturakh [An esophagoplasty at cancer and good- quality strictures]. Moscow, RF: Meditsina; 1990. 114 р. 2. Sotnikov AV. Vibratsionnye i endokhirurgicheskie sposoby rasshireniia rubtsovykh suzhenii pishchevoda [Vibratory and endosurgical ways of expansion of cicatrical esophageal stenoses]. V: 2-i Moskovskii Mezhdunarodnyi kongres po endoskopicheskoi khirurgii 23–25 apr 1997 g: sb tez. Moskva, RF; 1997. Р. 334-5. p ( ) 5. Gallinger YuI, Godzhello EA. Operativnaia endoskopiia pishchevoda [Operational endoscopy of an esophagus]. Moscow, RF; 1999. 273 р. p ( ) 5. Gallinger YuI, Godzhello EA. Operativnaia endoskopiia pishchevoda [Operational endoscopy of an esophagus]. Moscow, RF; 1999. 273 р. 6. Novik AA, Matveev SA, Ionova TI, Maksimov AG, Povzun AS, Sukhonos YuA, Tsepkova AA. Otsenka kachestva zhizni bol'nogo v meditsine [An assessment of quality of life of the patient in medicine]. Klinich Meditsina. 2000;(2):10-3. 6. Novik AA, Matveev SA, Ionova TI, Maksimov AG, Povzun AS, Sukhonos YuA, Tsepkova AA. Otsenka kachestva zhizni bol'nogo v meditsine [An assessment of quality of life of the patient in medicine]. Klinich Meditsina. 2000;(2):10-3. 6. Novik AA, Matveev SA, Ionova TI, Maksimov AG, Povzun AS, Sukhonos YuA, Tsepkova AA. Otsenka kachestva zhizni bol'nogo v meditsine [An assessment of quality of life of the patient in medicine]. Klinich Meditsina. 2000;(2):10-3. 3. Chernousov AF, Bogopolskiy PM, Kurbanov FS. Khirurgiia pishchevoda [Esophagus surgery]: ruk dlia Received 26.02.2016 Accept 15.04.2016 Сведения об авторах: Сведения об авторах: д р Петухов А.В. – к.м.н., доцент кафедры госпитальной хирургии УО «Витебский государственный ордена Дружбы народов медицинский университет». Адрес для корреспонденции: Республика Беларусь, 210023, г. Витебск, пр. Фрунзе, 27, УО «Витебский госу- дарственный ордена Дружбы народов медицинский университет», кафедра госпитальной хирургии. E-mail: alex.v.pet@gmail.com – Петухов Алексей Владимирович. 66
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Effects and Implementation of a Mindfulness and Relaxation App for Patients With Cancer: Mixed Methods Feasibility Study
JMIR cancer
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Abstract Background: Cancer diagnosis and cancer treatment can cause high levels of distress, which is often not sufficiently addressed in standard medical care. Therefore, a variety of supportive nonpharmacological treatments have been suggested to reduce distress in patients with cancer. However, not all patients use these interventions because of limited access or lack of awareness. To overcome these barriers, mobile health may be a promising way to deliver the respective supportive treatments. Objective: The aim of this study is to evaluate the effects and implementation of a mindfulness and relaxation app intervention for patients with cancer as well as patients’ adherence to such an intervention. Methods: In this observational feasibility study with a mixed methods approach, patients with cancer were recruited through the web and through hospitals in Switzerland. All enrolled patients received access to a mindfulness and relaxation app. Patients completed self-reported outcomes (general health, health-related quality of life, anxiety, depression, distress, mindfulness, and fear of progression) at baseline and at weeks 4, 10, and 20. The frequency of app exercise usage was gathered directly through the app to assess the adherence of patients. In addition, we conducted interviews with 5 health professionals for their thoughts on the implementation of the app intervention in standard medical care. We analyzed patients’self-reported outcomes using linear mixed models (LMMs) and qualitative data with content analysis. Results: A total of 100 patients with cancer (74 female) with a mean age of 53.2 years (SD 11.6) participated in the study, of which 25 patients used the app regularly until week 20. LMM analyses revealed improvements in anxiety (P=.04), distress (P<.001), fatigue (P=.01), sleep disturbance (P=.02), quality of life (P=.03), and mindfulness (P<.001) over the course of 20 weeks. Further LMM analyses revealed a larger improvement in distress (P<.001), a moderate improvement in anxiety (P=.001), and a larger improvement in depression (P=.03) in patients with high levels of symptoms at baseline in the respective domains. The interviews revealed that the health professionals perceived the app as a helpful addition to standard care. They also made suggestions for improvements, which could facilitate the implementation of and adherence to such an app. Conclusions: This study indicates that a mindfulness and relaxation app for patients with cancer can be a feasible and effective way to deliver a self-care intervention, especially for highly distressed patients. Abstract Future studies should investigate if the appeal of the app can be increased with more content, and the effectiveness of such an intervention needs to be tested in a randomized controlled trial. (JMIR Cancer 2021;7(1):e16785) doi: 10.2196/16785 Effects and Implementation of a Mindfulness and Relaxation App for Patients With Cancer: Mixed Methods Feasibility Study Michael Mikolasek1, MSc; Claudia Margitta Witt1,2,3, MBA, MD; Jürgen Barth1, PhD 1Institute for Complementary and Integrative Medicine, University Hospital Zurich and University of Zurich, Zurich, Switzerland 2Institute for Social Medicine, Epidemiology and Health Economics, Charité, Universitätsmedizin Berlin, Berlin, Germany 3Center for Integrative Medicine, University of Maryland School of Medicine, Baltimore, MD, United States Corresponding Author: Michael Mikolasek, MSc Institute for Complementary and Integrative Medicine University Hospital Zurich and University of Zurich Sonneggstrasse 6 Zurich, 8091 Switzerland Phone: 41 44 255 51 49 Fax: 41 44 255 43 94 Email: michael.mikolasek@usz.ch Original Paper Effects and Implementation of a Mindfulness and Relaxation App for Patients With Cancer: Mixed Methods Feasibility Study Michael Mikolasek1, MSc; Claudia Margitta Witt1,2,3, MBA, MD; Jürgen Barth1, PhD 1Institute for Complementary and Integrative Medicine, University Hospital Zurich and University of Zurich, Zurich, Switzerland 2Institute for Social Medicine, Epidemiology and Health Economics, Charité, Universitätsmedizin Berlin, Berlin, Germany 3Center for Integrative Medicine, University of Maryland School of Medicine, Baltimore, MD, United States Corresponding Author: Mikolasek et al JMIR CANCER Mikolasek et al JMIR CANCER Original Paper https://cancer.jmir.org/2021/1/e16785 Michael Mikolasek1, MSc; Claudia Margitta Witt1,2,3, MBA, MD; Jürgen Barth1, PhD 1Institute for Complementary and Integrative Medicine, University Hospital Zurich and University of Zurich, Zurich, Switzerland 2Institute for Social Medicine, Epidemiology and Health Economics, Charité, Universitätsmedizin Berlin, Berlin, Germany 3Center for Integrative Medicine, University of Maryland School of Medicine, Baltimore, MD, United States Study Design For this feasibility study, we used a mixed methods approach. For quantitative data, we assessed 4 paper-and-pencil questionnaires that were sent to patients with cancer at baseline and at weeks 4, 10, and 20. Demographics and patient characteristics were assessed at baseline, and health outcomes (physical, mental, and social health, health-related quality of life, anxiety, depression, distress, mindfulness, and fear of progression) were assessed over the 4 time points. Qualitative data consisted of semistructured interviews with 5 health professionals. In those interviews, we inquired about health professionals’ perspectives on a mindfulness- and relaxation-based mHealth intervention for patients with cancer and its implementation in standard medical care. To receive feedback from different health professionals, we conducted 2 face-to-face group interviews (1 interview with 2 nursing experts and the second interview with 2 psychologists providing MBM treatment for patients with cancer) and 1 individual interview with an oncologist. All interviewees received access to the app before the interview and could test the app. The interviewer also demonstrated the app and its content to the interviewees before the interview started. However, the uptake of supportive treatments in distressed patients with cancer is moderate [17]. Barriers for the uptake of such treatments include stigmatization, unawareness of such interventions, or limited access [18,19]. This is problematic because untreated, elevated levels of distress can lead to additional negative effects, such as reduced quality of life, daily functioning, and lower adherence to medical treatment [20,21]. Access can be restricted, for instance, because of geographical distance, lack of treatment providers or knowledge thereof, and financial constraints [22-24]. To overcome these limitations in access, eHealth and mobile health (mHealth) interventions have been proposed. eHealth is defined more broadly as the delivery of health services or information through the internet and related technologies [25], whereas mHealth uses mobile technologies such as smartphones for the delivery of health services [26]. So far, research indicates that eHealth interventions with mindfulness or relaxation components can have beneficial effects on health outcomes in various patient populations [27-29]. However, eHealth studies focusing on patients with cancer have shown inconsistent results [30,31]. Nonetheless, eHealth interventions seem promising because they can have positive effects on the well-being of patients with cancer [31]. To assess the feasibility of our mHealth intervention, we used the RE-AIM implementation science framework [37]. Ethical approval for the study was granted in April 2016 by the cantonal ethics committee Zurich (BASEC-Nr. Introduction The aim of this study is to assess the feasibility of this mHealth intervention using the Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) evaluation framework, which was developed for the evaluation of public health interventions [37]. Although the results for the reach of the dimensions, adoption over the course of 10 weeks, and maintenance were published elsewhere [36], the present analyses focus on the 3 dimensions of effectiveness, adoption, and implementation over the course of 20 weeks to assess the pre-post effects of the app on a variety of health outcomes and adherence to the app intervention. In doing so, we investigate whether such an app may be a beneficial, supportive care tool for patients with cancer. Background Cancer diagnosis and subsequent medical treatments can cause high levels of distress [1-4]. However, adequate psychological support for patients with cancer is often lacking in standard medical care [5,6]. Therefore, a variety of supportive treatments have been suggested to reduce distress in patients with cancer, such as mind-body medicine (MBM) [7]. MBM combines various effective treatments such as mindfulness meditation, relaxation, yoga, and tai chi [7,8]. Such MBM treatments can have beneficial effects on cancer-related symptoms, such as pain, fatigue, and sleep disturbance [9-11]. Furthermore, MBM treatments can have beneficial effects on the quality of life of patients with cancer [12-14]. These treatments can be provided through guided MBM programs for patients with cancer, where the patients learn various exercises (eg, physical exercises, relaxation, and stress reduction) and are encouraged to practice these newly learned exercises at home [15,16]. KEYWORDS mobile app; mobile phone; mindfulness; relaxation; cancer; qualitative research; implementation science; mHealth; evaluation study; patient compliance; patient participation; patient preference JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 1 (page number not for citation purposes) https://cancer.jmir.org/2021/1/e16785 XSL•FO RenderX JMIR CANCER Mikolasek et al Mikolasek et al Study Design 2016-00258), and we registered the study in the German Clinical Trials Register (DRKS00010481). Although mHealth interventions have some advantages over web-based eHealth interventions (eg, more flexible access because of mobility, the possibility of reaching a large number of patients because of the large popularity of smartphones), little is known about the best practices for the implementation of mHealth interventions [32,33]. In addition, mHealth research so far indicates that the adoption of mHealth interventions by health professionals and patients can be inhibited by various factors, such as perceived usefulness and ease of use [34,35]. Furthermore, there is a lack of mHealth studies with mindfulness or relaxation-based interventions [27]. Therefore, we developed a research app to conduct a feasibility study of a mindfulness- and relaxation-based mHealth intervention for patients with cancer [36]. The app included 3 exercises, namely, mindfulness meditation, guided imagery, and progressive muscle relaxation. https://cancer.jmir.org/2021/1/e16785 JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 2 (page number not for citation purposes) App Intervention All enrolled patients received the mindfulness and relaxation app, which was specifically developed for this study and only available for patients participating in the study. The app could be downloaded in the Apple iTunes store and Google Play Store for Android devices and accessed with a code, which was provided to the patients after study inclusion. The app offered 3 exercises: mindfulness meditation, guided imagery, and progressive muscle relaxation. The exercises were included in the app as audio files with a duration of approximately 15 minutes each, and the patients could choose between a female or male narrator. Patients were free to choose which exercises they wanted to use and how often they wanted to practice. However, we recommended to the patients to use an exercise of their choice on a daily basis, ideally 5 times per week. To help patients practice regularly, the app included an optional notification feature that patients could set up to receive a daily push notification on the mobile device, reminding them to practice at an individually set time. Information about the use of exercises (exercise type, date, and start and end times) was saved in the backend and was only accessible to the researchers as an XML log file. More information about the app is presented in a previously published paper [36]. We measured anxiety and depression using the Hospital Anxiety and Depression Scale (HADS). The HADS assesses 7 items for the subscales anxiety (Cronbach α=.79) and depression (Cronbach α=.67) on a 4-point scale, with a maximum score of 21 for each subscale. A score of up to 7 is considered normal, a score between 8 and 11 is considered borderline, and a score above 11 is considered caseness [44]. For the assessment of fear of progression, we administered the Fear of Progression Questionnaire-Short Form (FoP-Q-SF) [45]. The FoP-Q-SF (Cronbach α=.81) consists of 12 items with a 5-point scale. A higher score indicates a greater fear of progression. We assessed PROMIS 29, FACT-G, and FMI at baseline and at weeks 4, 10, and 20 and HADS, FoP-Q-SF, and Distress Thermometer at baseline and at weeks 10 and 20. We defined a continuous app user as a patient who regularly used the app exercises (at least one exercise per week). Effects As we conducted a single-arm study without a control group, we were not able to assess the effectiveness of the app intervention. Therefore, for the RE-AIM dimension effectiveness, we looked into pre-post effects in a variety of health outcomes relevant to patients with cancer. We assessed physical, mental, and social health using the Patient-Reported Outcomes Measurement Information System (PROMIS 29) [38]. PROMIS 29 is a 29-item scale assessing 7 health domains: physical function (Cronbach α=.81), fatigue (Cronbach α=.94), pain interference (Cronbach α=.96), depressive symptoms (Cronbach α=.85), anxiety (Cronbach α=.81), ability to participate in social roles and activities (Cronbach α=.88), and sleep disturbance (Cronbach α=.86) with 4 items, each on a 5-point scale, and pain intensity with a single item on a 10-point numeric rating scale. Adoption For the RE-AIM dimension adoption, we looked at the number of completed app exercises over 20 weeks and app exercise preferences. We reported the median of completed app exercises by all enrolled patients per week as well as the median of completed app exercises by continuous app users. For exercise preferences, we reported frequencies of used exercises for all enrolled patients, stratified by gender of the patient and the narrator. Implementation For the RE-AIM dimension implementation, we reported results from interviews with health professionals regarding their opinion on the implementation of the app intervention in addition to standard medical care. In the interviews, we inquired about the general impression regarding the app, implementation of the app as an addition to standard medical care, and suggestions for improvements. For the assessment of health-related quality of life for patients with cancer, we administered the Functional Assessment of Cancer Therapy—General (FACT-G) [39,40]. The FACT-G consists of 4 subscales: physical well-being (Cronbach α=.85), social well-being (Cronbach α=.76), emotional well-being (Cronbach α=.70), and functional well-being (Cronbach α=.79), measured with 27 items on a 5-point scale. A higher score indicates a better quality of life. Participants Patients were eligible if they (1) had any cancer diagnosis at any stage of cancer, (2) were aged 18 years or older, and (3) owned either an iPhone (Apple Inc). or an Android-based smartphone with at least a weekly connection to the internet. Patients were excluded if they had suicidal ideation or insufficient German language skills, if they intended to move to another country, or if they had insufficient knowledge on how to use a smartphone. The patient recruitment process is described in detail elsewhere [36]. For the interviews with health professionals, we invited experts (an oncologist, nursing experts, JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 2 (page number not for citation purposes) JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 2 (page number not for citation purposes) XSL•FO RenderX JMIR CANCER Mikolasek et al and psychologists) from the University Hospital Zurich, who provide health care for patients with cancer. For the assessment of mindfulness, we administered the short version of the Freiburg Mindfulness Inventory (FMI) [43]. The FMI (Cronbach α=.87) assesses mindfulness with 14 items on a 4-point scale, with a higher score indicating higher mindfulness. and psychologists) from the University Hospital Zurich, who provide health care for patients with cancer. https://cancer.jmir.org/2021/1/e16785 App Intervention We counted an exercise as completed if the patient played the exercise audio file for at least 10 minutes of the total time of 15 minutes. We defined an intervention dropout as a patient who stopped using the exercises for 4 consecutive weeks because regular practice might be a prerequisite for a beneficial intervention. We defined the first week when the patient stopped using the exercises as a dropout week. A patient who never used an app exercise was counted as a week 1 intervention dropout. JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 3 (page number not for citation purposes) Sample Size One aspect evaluated in our feasibility study was the characteristics and number of patients with cancer who participated in the study (evaluation dimension reach), which was reported previously [36]. Therefore, we did not perform an a priori analysis to determine the required sample size for adequate power. However, we aimed to recruit at least 100 patients, which is sufficient to achieve 80% power for a For the assessment of distress, we administered the Distress Thermometer [41]. The Distress Thermometer is a numeric rating scale, ranging from 0 to 10. A score of 5 or higher is considered to indicate clinically relevant distress [42]. https://cancer.jmir.org/2021/1/e16785 JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 3 (page number not for citation purposes) XSL•FO RenderX Mikolasek et al JMIR CANCER two-tailed t test with an α level set at .05 and a small effect size of Cohen d of 0.28. included as a fixed effect. For group analyses, (continuous app users vs intervention dropouts), we added group and time-by-group as fixed effects. Hedge g effect sizes were calculated as mean differences (baseline and week 20) divided by pooled SDs for each health outcome of interest. Qualitative Data All printed case report forms were entered by trained researchers into the electronic database REDCap (Research Electronic Data Capture), which was hosted at the University Hospital Zurich. All analyses were carried out in SPSS version 25.0 (IBM Corp). For the dimension implementation, we recorded the interviews and transcribed the interviews verbatim. We used thematic coding for structuring the interviews using MAXQDA 11 (VERBI Software), and we used content analysis according to Mayring [46]. For baseline characteristics of patients, we used descriptive statistics (frequencies and percentages for categorical variables and mean and SD for continuous variables). For the analyses of pre-post effects, we used linear mixed models (LMMs) to analyze changes over time (baseline, week 4, week 10, and week 20) in health outcomes as well as differences between continuous app users and intervention dropouts in health outcomes. All patients who provided baseline data were included in the analyses, and because we used LMMs, patients with missing data in weeks, 4, 10, and 20 questionnaires were included. The dependent variables were the 7 PROMIS 29 domains, FACT-G, HADS subscales anxiety and depression, Distress Thermometer, FMI, and FoP-Q-SF. Furthermore, we looked at the changes in the respective health outcomes for subsamples with high distress (Distress Thermometer score ≥5), high anxiety (HADS anxiety score of ≥8), and high depression (HADS depression score of ≥8). As a covariance type, we used an autoregressive covariance structure (AR1). Time was JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 4 (page number not for citation purposes) Patient Characteristics Between June 2016 and December 2018, we were able to recruit 100 patients with cancer, all of whom provided baseline information. At week 20, 72 (72%) patients completed questionnaire 4 (Figure 1). Baseline characteristics of all enrolled patients (N=100) as well as subsamples of patients with high distress (62/100, 62%), high anxiety (35/100, 26%), and high depression (20/100, 20%) are summarized in Table 1. Most patients (74/100, 74%) were female. The mean age of all patients was 53.24 (SD 11.55) years, ranging from 23 to 84 years. Patients predominantly owned an iPhone smartphone (67/100, 67%), whereas 30 patients (30/100, 30%) owned an Android smartphone, and a few (3/100, 3%) owned both. Figure 1. Flowchart. JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 4 https://cancer.jmir.org/2021/1/e16785 (page number not for citation purposes) FO Figure 1. Flowchart. JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 4 (page number not for citation purposes) JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 4 (page number not for citation purposes) https://cancer.jmir.org/2021/1/e16785 https://cancer.jmir.org/2021/1/e16785 JMIR CANCER Mikolasek et al Table 1. Demographics for the total sample and high distress, high depression, and high anxiety subsamples. Patient Characteristics High depressionc subsample (n=20) High anxietyb subsample (n=35) High distressa subsample (n=62) Total sample (N=100) Patient demographics Gender, n (%) 15 (75) 26 (74) 48 (77) 74 (74) Female 5 (25) 9 (26) 14 (23) 26 (26) Male 51.74 (11.63) 51.22 (10.67) 52.74 (10.67) 53.24 (11.55) Age (years), mean (SD) Type of cancer, n (%) 8 (40) 18 (51) 27 (44) 39 (39) Breast cancer 3 (15) 2 (6) 7 (11) 9 (9) Colon cancer 0 (0) 2 (6) 3 (5) 6 (6) Ovarian or cervical cancer 1 (5) 0 (0) 3 (5) 6 (6) Lung cancer 8 (40) 13 (37) 22 (35) 40 (40) Others Status of cancer treatment, n (%) 11 (55) 24 (69) 33 (53) 46 (46) Total removal 5 (25) 6 (17) 15 (24) 25 (25) Recurrence or incomplete removal 2 (10) 1 (3) 1 (2) 3 (3) Uncertain 4 (20) 4 (11) 13 (21) 26 (26) Other Highest education, n (%) 0 (0) 2 (6) 2 (3) 3 (3) Primary school 5 (25) 5 (14) 16 (26) 22 (22) Apprenticeship 7 (35) 14 (40) 21 (34) 41 (41) Secondary education 7 (35) 14 (40) 22 (35) 33 (33) University degree 1 (5) 0 (0) 1 (2) 1 (1) Unknown aDistress Thermometer score ≥5. bHospital Anxiety and Depression Scale anxiety score ≥8. cHospital Anxiety and Depression Scale depression score ≥8. Effects The health outcome values at baseline and at week 20 as well as effect sizes for the total sample and the high distress, high anxiety, and high depression subsamples are presented in Table 2. Baseline distress was 5.29 (SD 2.31); therefore, patients were on average above an assumed clinically relevant threshold of 5, with 62% of patients (62/100) reporting a distress level of 5 or higher. At week 20, distress decreased to an average of 4.1 (SD 2.12; Hedge g=0.53). The mean HADS anxiety score at baseline was 6.88 (SD 3.50) and dropped to 6.31 (SD 3.78; Hedge g=0.16) at week 20. Overall, 35% (35/100) of patients reported an elevated HADS anxiety score (≥8) at baseline (mean 10.71, SD 1.95), which dropped to 8.85 (SD 3.50; Hedge g=0.68) at week 20. For HADS depression, the mean score at baseline was 4.96 (SD 2.78) and dropped to 4.55 (SD 3.31; Hedge g=0.14) at week 20. Patient Characteristics Overall, 20% (20/100) of patients reported an elevated HADS depression score (≥8) at baseline (mean 9.00, SD 1.12), which dropped to 8.85 (SD 3.50; Hedge g=0.61) at week 20. For the remaining measures without a proposed threshold (PROMIS, FACT-G, FMI, and FoP-Q-SF), changes from baseline to week 20 were small, with Hedges g effect sizes ranging from 0.04 to 0.33. ble 1. Demographics for the total sample and high distress, high depression, and high anxiety subsamples. aDistress Thermometer score ≥5. reported an elevated HADS anxiety score (≥8) at baseline (mean 10.71, SD 1.95), which dropped to 8.85 (SD 3.50; Hedge g=0.68) at week 20. For HADS depression, the mean score at baseline was 4.96 (SD 2.78) and dropped to 4.55 (SD 3.31; Hedge g=0.14) at week 20. Overall, 20% (20/100) of patients reported an elevated HADS depression score (≥8) at baseline (mean 9.00, SD 1.12), which dropped to 8.85 (SD 3.50; Hedge g=0.61) at week 20. For the remaining measures without a proposed threshold (PROMIS, FACT-G, FMI, and FoP-Q-SF), changes from baseline to week 20 were small, with Hedges g effect sizes ranging from 0.04 to 0.33. reported an elevated HADS anxiety score (≥8) at baseline (mean 10.71, SD 1.95), which dropped to 8.85 (SD 3.50; Hedge g=0.68) at week 20. For HADS depression, the mean score at baseline was 4.96 (SD 2.78) and dropped to 4.55 (SD 3.31; Hedge g=0.14) at week 20. Overall, 20% (20/100) of patients reported an elevated HADS depression score (≥8) at baseline (mean 9.00, SD 1.12), which dropped to 8.85 (SD 3.50; Hedge g=0.61) at week 20. For the remaining measures without a proposed threshold (PROMIS, FACT-G, FMI, and FoP-Q-SF), changes from baseline to week 20 were small, with Hedges g effect sizes ranging from 0.04 to 0.33. JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 5 (page number not for citation purposes) Effects Mean values of health outcomes at baseline and week 20, response rate (n), and effect sizes (N=100). Week 20 Baseline Sample and outcome aHADS: Hospital Anxiety Depression Scale; negative effect=improvement. bPROMIS physfunct: Patient-Reported Outcomes Measurement Information System Physical Function; positive effect=improvement. cPROMIS anxiety: Patient-Reported Outcomes Measurement Information System Anxiety; negative effect=improvement. dPROMIS depression: Patient-Reported Outcomes Measurement Information System Depression; negative effect=improvement. ePROMIS fatigue: Patient-Reported Outcomes Measurement Information System Fatigue; negative effect=improvement. fPROMIS sleep: Patient-Reported Outcomes Measurement Information System Sleep Disturbance; negative effect=improvement. gPROMIS social: Patient-Reported Outcomes Measurement Information System Ability to Participate in Social Roles and Activities; positive effect=improvement. hPROMIS pain: Patient-Reported Outcomes Measurement Information System Pain Interference; negative effect=improvement. iFACT-G: Functional Assessment of Cancer Therapy—General; positive effect=improvement. jFMI: Freiburg Mindfulness Inventory; positive effect=improvement. kFoP: Fear of Progression; negative effect=improvement. lDistress Thermometer score ≥5; negative effect=improvement; n=62. mHADS anxiety score ≥8; negative effect=improvement; n=35. nHADS depression score ≥8; negative effect=improvement; n=20. The results for effects over time are presented in Table 3. LMM analyses revealed that there was a significant decrease over time and fear of progression. LMM analyses for the subsamples revealed that distress decreased significantly in the high distress aHADS: Hospital Anxiety Depression Scale; negative effect=improvement. HADS: Hospital Anxiety Depression Scale; negative effect=improvement. bPROMIS physfunct: Patient-Reported Outcomes Measurement Information System Physical Function; positive effect=improvement. cPROMIS anxiety: Patient-Reported Outcomes Measurement Information System Anxiety; negative effect=improvement. dPROMIS depression: Patient-Reported Outcomes Measurement Information System Depression; negative effect=improvement. ePROMIS fatigue: Patient-Reported Outcomes Measurement Information System Fatigue; negative effect=improvement. fPROMIS sleep: Patient-Reported Outcomes Measurement Information System Sleep Disturbance; negative effect=improvement. gPROMIS social: Patient-Reported Outcomes Measurement Information System Ability to Participate in Social Roles and Activities; positive effect=improvement. h gPROMIS social: Patient-Reported Outcomes Measurement Information System Ability to Participate in Social Roles and Activities; positive effect=improvement. iFACT-G: Functional Assessment of Cancer Therapy—General; positive effect=improvement. jFMI: Freiburg Mindfulness Inventory; positive effect=improvement. kFoP: Fear of Progression; negative effect=improvement. lDistress Thermometer score ≥5; negative effect=improvement; n=62. HADS anxiety score ≥8; negative effect=improvement; n=35. The results for effects over time are presented in Table 3. LMM analyses revealed that there was a significant decrease over time in distress (P<.001), fatigue (P=.01), sleep disturbance (P=.02), and anxiety (P=.04) measured with the HADS. Furthermore, there was a significant increase in quality of life (P=.03) and mindfulness (P<.001). Effects The health outcome values at baseline and at week 20 as well as effect sizes for the total sample and the high distress, high anxiety, and high depression subsamples are presented in Table 2. Baseline distress was 5.29 (SD 2.31); therefore, patients were on average above an assumed clinically relevant threshold of 5, with 62% of patients (62/100) reporting a distress level of 5 or higher. At week 20, distress decreased to an average of 4.1 (SD 2.12; Hedge g=0.53). The mean HADS anxiety score at baseline was 6.88 (SD 3.50) and dropped to 6.31 (SD 3.78; Hedge g=0.16) at week 20. Overall, 35% (35/100) of patients JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 5 (page number not for citation purposes) https://cancer.jmir.org/2021/1/e16785 XSL•FO RenderX Mikolasek et al Mikolasek et al JMIR CANCER Table 2. Mean values of health outcomes at baseline and week 20, response rate (n), and effect sizes (N=100). Hedges g (95% CI) Week 20 Baseline Sample and outcome n Mean (SD) n Mean (SD) Total sample −0.16 (−0.46 to 0.15) 71 6.31 (3.78) 99 6.88 (3.50) HADSa anxiety −0.14 (−0.44 to 0.17) 71 4.55 (3.31) 100 4.96 (2.78) HADS depression −0.53 (−0.84 to 0.22) 71 4.10 (2.12) 99 5.29 (2.31) Distress −0.04 (−0.34 to 0.27) 71 46.30 (7.32) 99 46.55 (6.54) PROMIS physfunctb −0.15 (−0.45 to −0.16) 70 55.01 (6.83) 99 55.97 (6.46) PROMIS anxietyc −0.18 (−0.49 to 0.12) 71 53.88 (7.81) 100 55.20 (6.81) PROMIS depressiond −0.38 (−0.69 to −0.07) 70 52.40 (10.31) 99 56.11 (9.23) PROMIS fatiguee −0.23 (−0.53 to 0.08) 70 49.52 (8.02) 100 51.44 (8.85) PROMIS sleepf 0.18 (−0.12 to 0.49) 71 49.84 (7.87) 99 48.42 (7.64) PROMIS socialg 0.10 (−0.41 to 0.21) 70 51.96 (9.38) 97 52.88 (9.10) PROMIS painh 0.29 (−0.02 to 0.59) 70 79.62 (14.81) 99 75.54 (13.85) FACT-Gi 0.51 (−0.20 to 0.83) 69 41.80 (6.42) 96 38.46 (6.62) FMIj −0.13 (−0.45 to 0.19) 64 30.28 (7.99) 93 31.33 (7.83) FoPk High distressl −1.36 (−1.79 to −0.94) 46 4.39 (2.19) 62 6.79 (1.36) Distress High anxietym −0.69 (−1.20 to −0.16) 26 8.85 (3.50) 35 10.71 (1.95) HADS anxiety High depressionn −0.61 (−1.27 to 0.05) 17 7.47 (3.52) 20 9.00 (1.12) HADS depression aHADS: Hospital Anxiety Depression Scale; negative effect=improvement Table 2. Mean values of health outcomes at baseline and week 20, response rate (n), and effect sizes (N=100). Table 2. JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 6 (page number not for citation purposes) https://cancer.jmir.org/2021/1/e16785 Effects bPROMIS physfunct: Patient-Reported Outcomes Measurement Information System Physical Function. bPROMIS physfunct: Patient-Reported Outcomes Measurement Information System Physical Function. cPROMIS anxiety: Patient-Reported Outcomes Measurement Information System Anxiety. dPROMIS depression: Patient-Reported Outcomes Measurement Information System Depression. ePROMIS fatigue: Patient-Reported Outcomes Measurement Information System Fatigue. fPROMIS sleep: Patient-Reported Outcomes Measurement Information System Sleep Disturbance. gPROMIS social: Patient-Reported Outcomes Measurement Information System Ability to Participate in Social Roles and Activities. hPROMIS pain: Patient-Reported Outcomes Measurement Information System Pain Interference. iFACT-G: Functional Assessment of Cancer Therapy—General. jFMI: Freiburg Mindfulness Inventory PROMIS depression: Patient-Reported Outcomes Measurement Information System Depression. ePROMIS fatigue: Patient-Reported Outcomes Measurement Information System Fatigue. fPROMIS sleep: Patient-Reported Outcomes Measurement Information System Sleep Disturbance. gPROMIS social: Patient-Reported Outcomes Measurement Information System Ability to Participate in Social Roles and Activities. hPROMIS pain: Patient-Reported Outcomes Measurement Information System Pain Interference. iFACT-G: Functional Assessment of Cancer Therapy—General jFMI: Freiburg Mindfulness Inventory. kFoP: Fear of Progression. kFoP: Fear of Progression. lDistress Thermometer score ≥5. lDistress Thermometer score ≥5. mHADS anxiety score ≥8. nHADS depression score ≥8. nHADS depression score ≥8. to 0 at week 9. For continuous app users, who completed an app exercise at least once per week until week 20, the median of completed exercises at week 1 was 6. For the subsequent weeks up to week 20, the median of completed exercises varied between a median of 3 and 5 for the continuous app users. https://cancer.jmir.org/2021/1/e16785 Effects No significant effects were found for physical functioning, anxiety measured with PROMIS, depression, ability to participate in social roles and activities, and fear of progression. LMM analyses for the subsamples revealed that distress decreased significantly in the high distress subsample (P<.001), anxiety decreased significantly in the high anxiety subsample (P=.001), and depression decreased significantly in the high depression subsample (P=.03). Dose-response analyses using LMMs with group-by-time revealed no significant results. JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 6 (page number not for citation purposes) JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 6 (page number not for citation purposes) https://cancer.jmir.org/2021/1/e16785 XSL•FO RenderX Mikolasek et al JMIR CANCER Table 3. Linear mixed models: estimates of fixed effect of time on health outcomes from baseline to week 20. Estimates of fixed effects (time) Sample and dependent variable P value t test (df) Estimate (95% CI) Total sample (N=100) .04 −2.04 (201.95) −0.40 (−0.79 to −0.01) HADSa anxiety .09 −1.71 (206.42) −0.29 (−0.62 to 0.04) HADS depression <.001 −3.96 (325.86) −0.41 (−0.62 to −0.21) Distress .66 −.45 (318.35) −0.13 (−0.68 to 0.43) PROMIS physfunctb .16 −1.42 (325.74) −0.46 (−1.09 to 0.18) PROMIS anxietyc .09 −1.72 (324.81) −0.52 (−1.11 to 0.07) PROMIS depressiond .01 −2.61 (324.73) −1.15 (−2.02 to −0.28) PROMIS fatiguee .02 −2.39 (322.65) −0.85 (−1.55 to −0.15) PROMIS sleepf .15 1.45 (314.63) 0.43 (−0.15 to 1.01) PROMIS socialg .74 −.34 (322.51) −0.14 (−0.94 to 0.66) PROMIS painh .03 2.16 (307.58) 1.13 (0.10 to 2.15) FACT-Gi <.001 4.46 (300.46) 1.11 (0.62 to 1.59) FMIj .13 −1.52 (180.05) −0.68 (−1.56 to .20) FoPk High distressl (n=62) <.001 −6.64 (200.45) −0.81 (−1.05 to −0.57) Distress High anxietym (n=35) .001 −3.47 (81.69) −1.13 (−1.77 to −0.48) HADS anxiety High depressionn (n=20) .03 −2.23 (47.99) −0.87 (−1.65 to −0.09) HADS depression inear mixed models: estimates of fixed effect of time on health outcomes from baseline to week 20. Table 3. Linear mixed models: estimates of fixed effect of time on health outcomes from baseline to week 20. Estimates of fixed effects (time) Sample and dependent variable Table 3. Linear mixed models: estimates of fixed effect of time on health outcomes from baseline to week 20. Estimates of fixed effects (time) Sample and dependent variable t test (df) Estimate (95% CI) .03 aHADS: Hospital Anxiety Depression Scale. aHADS: Hospital Anxiety Depression Scale. Adoption According to our definition, 25% (25/100) of all enrolled patients used the app continuously (ie, at least one completed exercise per week) at week 20 of the intervention. The average number (median) of completed exercises during the 20-week intervention for all patients as well as continuous app users is presented in Figure 2. Across all patients, the median of completed exercises was 2 during the first week and dropped The percentage of completed exercises is presented in Figure 3. All patients together completed 3526 exercises. Mindfulness meditation was used most often, with a total of 1633 completed JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 7 (page number not for citation purposes) https://cancer.jmir.org/2021/1/e16785 XSL•FO RenderX JMIR CANCER Mikolasek et al exercises (46.31%), followed by guided imagery with 1077 completed exercises (30.55%). Progressive muscle relaxation was used least frequently, with 816 completed exercises (23.14%). In both mindfulness meditation and guided imagery, the female narrator voice was preferred. narrator vs 1031 completed exercises with a male narrator). However, male patients preferred exercises with a male narrator (389 completed exercises with a male narrator vs 171 completed exercises with a female narrator). The probability of choosing the same sex in audio files is therefore increased for women by 87% and for men by 127%, which corresponds to a 2-fold higher preference for the same sex as the narrator. Furthermore, female patients showed a preference for exercises with a female narrator (1935 completed exercises with a female Furthermore, female patients showed a preference for exercises with a female narrator (1935 completed exercises with a female y , p g preference for the same sex as the narrator. Figure 2. Completed app exercises by all enrolled patients (N=100) and by continuous app users (n=25) per week (median). Figure 3. Completed exercises (3526) of all patients (N=100) over 20 weeks by type (mindfulness meditation, guided imagery, and progressive muscle relaxation), gender of patient (male and female), and sex of narrator (male and female). Percentages refer to the total number of exercises per gender. JMIR C 2021 | l 7 | i 1 | 16785 | 8 htt // j i /2021/1/ 16785 Figure 2. Completed app exercises by all enrolled patients (N=100) and by continuous app users (n=25) per week (median). gure 2. Completed app exercises by all enrolled patients (N=100) and by continuous app users (n=25) per week (median). Implementation [...] And you can’t just hand out the flyer. You also need to say a few words [about the app] and that’s why I sometimes forgot [to mention the app]. Due to shortage of time. All health professionals perceived the app as appealing, clearly structured, and as a helpful supportive tool. In addition, the MBM psychologists liked the app as an addition to the 10-week face-to-face MBM course and appreciated the app as a good self-help tool complementing the course. The oncologist also stated that many patients with cancer look for something they can use to add to standard care and an app can provide a low threshold aid. As a negative aspect, a nursing expert stated that a smartphone is required and not every patient possesses such a device. The nursing experts also mentioned that the nurses oftentimes forgot about the app because it is not part of standard care. Therefore, the nursing experts stated that it might be helpful to better inform the nurses about the app and setting up standards regarding the communication about the app, for example, when to inform the patients and how. In addition, the nursing experts stated that it might be helpful if they had a demonstration device at the oncology unit so that they could better explain the app to the patients. All interviewed health professionals further mentioned that patients with cancer are very diverse and that although some patients are very eager to try out various treatments, others are not. One MBM therapist also stated that not all patients perceive relaxation as important and that those patients might need some additional information which indicates why relaxation is good for them. All health professionals also stated that implementing such an app does not result in a lot of additional work for them and they appreciate the app, which they could recommend to suitable patients. All health experts made various suggestions for improving the app. A shared opinion was that the content of the app (ie, number and variety of exercises) could be increased, as over an extended period, patients might get bored with a choice limited to 3 exercises. A nursing expert suggested that a new exercise could, for instance, be unlocked after completing the same exercise several times. Implementation A total of 5 health professionals took part in an interview: 2 female nursing experts (one from an inpatient unit and the other from an outpatient oncology unit), 2 female MBM psychologists, and 1 male oncologist. Interviews were conducted between January and March 2018 and lasted for an average of 45 minutes (SD 9.54). The qualitative analysis of the interviews yielded 4 themes: (1) general impression of the app, (2) suggestions for improvement, (3) implementation in standard care, and (4) experience with recommending the app to patients. The interviewees mentioned several factors that could influence the implementation of a mindfulness- and relaxation-based app into standard care. Both nursing experts and one of the MBM psychologists stated that the time point when the information of the app is delivered to the patient might be important. These health professionals mentioned that the patients were bombarded with information during the first consultation or during the first day when a patient enters the hospital and additional information about the app might overwhelm some patients. The outpatient nursing expert also mentioned that they are often limited because of time constraints during consultation hours: Overall, the general impression of the app was positive. For instance, the oncologist summarized his impression of the app as follows: I think [the app] is a very helpful thing because it is relatively easy [to use]. You can test it. You can try it and if you like it, you can integrate it relatively easy into everyday life. I think it is very practical. It is a practical thing and if patients are interested, I also see that they take it up willingly. On the one hand there are the concerns of the patients, which you have to discuss. But you also have a little bit of pressure, [to tell them] all relevant information. [...] And sometimes it’s already two minutes before the end [of the consultation]. [...] And you can’t just hand out the flyer. You also need to say a few words [about the app] and that’s why I sometimes forgot [to mention the app]. Due to shortage of time. On the one hand there are the concerns of the patients, which you have to discuss. But you also have a little bit of pressure, [to tell them] all relevant information. [...] And sometimes it’s already two minutes before the end [of the consultation]. Adoption Figure 3. Completed exercises (3526) of all patients (N=100) over 20 weeks by type (mindfulness meditation, guided imagery, and progressive muscle relaxation), gender of patient (male and female), and sex of narrator (male and female). Percentages refer to the total number of exercises per gender. JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 8 https://cancer.jmir.org/2021/1/e16785 (page number not for citation purposes) FO Figure 3. Completed exercises (3526) of all patients (N=100) over 20 weeks by type (mindfulness meditation, guided imagery, and progressive musc relaxation), gender of patient (male and female), and sex of narrator (male and female). Percentages refer to the total number of exercises per gende JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 8 (page number not for citation purposes) https://cancer.jmir.org/2021/1/e16785 JMIR CANCER Mikolasek et al If I could make a wish, then I would say, it would be totally cool to have an accompanying Mind Body Medicine app. That is to say that a lot of exercises—not all of them—but a lot of exercises we do [could be added to the app]. Possibly also guided body exercises. That would be totally cool. https://cancer.jmir.org/2021/1/e16785 JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 9 (page number not for citation purposes) Principal Findings In this study, we explored the feasibility of a mindfulness- and relaxation-based self-help app for patients with cancer. To evaluate the feasibility, we used the RE-AIM framework [37], and in this analysis, we focused on the framework dimensions effectiveness, adoption, and implementation. Our findings support the feasibility of this mHealth intervention. The results indicate that the intervention might have beneficial effects on patients’ distress and quality of life. Furthermore, the mHealth intervention is accepted by the target population as well as by health professionals. The results from the interviews with health professionals provide some insights into the implementation of a mindfulness and relaxation mHealth intervention into standard care. In general, all interviewed health professionals perceived the app as a helpful addition to standard care. The health professionals also suggested some improvements, which might increase the acceptance and long-term use of such mHealth interventions by patients. A suggested improvement shared by all health professionals is the increase in the content of the app, such as additional exercises or variations of the exercises. A statement about the implementation of the mHealth intervention given by several health professionals was the adequate provision of information. One of the interviewed MBM psychologists as well as the nursing experts stated that patients with cancer are, on the one hand, flooded with information, especially when they start their treatment. However, the provision of some information to the patients about a mHealth intervention is necessary, at least to let the patients know about the existing intervention. On the other hand, nursing experts also mentioned that nurses often forgot about the intervention, although they approve this kind of intervention. Therefore, a standardized procedure for informing patients about the mHealth intervention might facilitate the implementation of the intervention. In addition, health professionals such as nurses might have to be informed regularly about such interventions because it is not part of their standard treatment; therefore, they might forget about it, as seen in this study. Regarding the recruitment process, the health professionals made the observation that female patients were more interested in this mHealth intervention. This is also reflected by the gender ratio in this study’s sample, with 76 female and 24 male patients with cancer, which is typical for complementary and alternative treatments [51-53]. This gender difference raises the question of whether an effort should be made to better recruit male patients with cancer for such an intervention. JMIR CANCER I was surprised that so many older patients had the app on their phone and also used the app regularly [...]. I had the impression, that it appeals to the young. [...]. But oftentimes, the older people have more time, because they don’t work anymore. recommendation of 5 exercises per week. We consider this a good adoption of the mHealth intervention because the intervention was set up as a self-care intervention without the involvement of a therapist or health professional. Mindfulness was the preferred exercise, followed by guided imagery and progressive muscle relaxation. However, mindfulness meditation exercises were also presented as the first choice in the app, whereas guided imagery was placed at the second position, and progressive muscle relaxation was placed at the third position. Therefore, the preference for mindfulness meditation could also be caused by the placement of the exercises in the app. These results regarding adoption are comparable with those of a study conducted by Kubo et al [48], in which patients with cancer received access to the commercially available mindfulness app Headspace (TM). In this study, 40 of 54 patients with cancer allocated to the intervention group completed the 8-week study, and 20 patients with cancer used the app on at least 50% of the days [48]. Principal Findings A nursing expert, for instance, mentioned during the interview that a focus on more technical aspects or facts could be more appealing to male patients. For the dimension effectiveness, we looked into pre-post effects. Our results suggest that the app might have the potential to reduce distress, fatigue, sleep disturbance, and anxiety as well as improve health-related quality of life and mindfulness. This is in line with a recent pilot study [47], in which a mobile mindfulness-based stress reduction program improved, among others, stress, anxiety, depression, sleep quality, quality of life, and mindfulness in patients with breast cancer with small to large effects. Furthermore, a recent randomized controlled trial conducted by Kubo et al [48] assessed the feasibility of a commercially available mindfulness program in which they targeted patients with cancer and their caregivers. This program leads to an increase in quality of life in patients with cancer with a medium effect size [48]. Similar to these findings, Rosen et al [49] reported that the quality of life of patients with breast cancer improved with a small effect size using a commercially available mindfulness course when compared with a control group. As depressive symptoms and anxiety were not significantly reduced in the total sample in our study, we also looked at subsamples with higher HADS scores. In the high anxiety and high depression subsamples, anxiety and depression, respectively, decreased significantly over time. This might indicate that a mindfulness and relaxation mHealth intervention is especially beneficial for patients with cancer with higher emotional distress. This is also in line with a study by Barth et al [50], where highly distressed patients benefited most from psycho-oncological interventions. However, we did not find any group effects when comparing continuous app users with intervention dropouts. This might indicate that our definition of users and dropouts is not precise enough or that another variable than time spent practicing is responsible for changes in outcomes. For adoption, our results showed that at week 20 of the intervention, 25 of 100 patients were using the app continuously. With 54 of 100 continuous app users at week 10 [36], this leads to a dropout rate of approximately 50% every 10 weeks. The 25 continuous app users practiced on average 3 to 5 times per week (median), which comes close to our initially stated Strengths, Limitations, and Future Directions Implementation An MBM psychologist suggested that every week, a different selection of exercises could be activated with alternating topics such as meditation, relaxation, self-compassion, or body exercises. In addition, the inclusion of exercises with different degrees of complexity was suggested. An MBM psychologist stated that exercises for beginners (eg, more detailed instructions, fewer moments of silence) as well as exercises for patients experienced in mindfulness and relaxation could be added. MBM psychologists and nursing experts also recommended that some exercises should be accompanied by soothing background music because longer periods of silence might be uncomfortable for some patients. They also recommended exercises with various lengths of time so that patients had more flexibility if they were facing time constraints or if they were too impatient for longer exercises. The oncologist mentioned that adding exercises specifically for sleep disorders might be a good addition to the app, especially for inpatients, because poor sleep in hospitals is very common. As an additional topic that could be added, he mentioned body exercises such as yoga. An MBM psychologist mentioned that an app mirroring the MBM course more closely would be great: Regarding their experience with recommending the app to patients, health professionals shared the opinion that female patients are more drawn to mindfulness and relaxation exercises. Furthermore, the MBM therapists stated that patients who already practiced some form of relaxation or meditation often did not participate in the study. The MBM therapists also noticed that the composition of the MBM group had an influence on how many patients were willing to try out the app. For instance, if one patient was very motivated and expressed interest in the app, hesitant patients sometimes followed suit and were willing to try the app as well. One MBM therapist also noticed that many older people were willing to use the app: JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 9 (page number not for citation purposes) XSL•FO RenderX XSL•FO RenderX Mikolasek et al JMIR CANCER https://cancer.jmir.org/2021/1/e16785 JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 10 (page number not for citation purposes) Acknowledgments This study was funded by the Swiss Cancer League (KLS-3564-02-2015). This study was funded by the Swiss Cancer League (KLS-3564-02-2015). Conflicts of Interest None declared. Strengths, Limitations, and Future Directions This study has several strengths and limitations. A strength of the study is the collection of objective data in the form of https://cancer.jmir.org/2021/1/e16785 JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 10 (page number not for citation purposes) XSL•FO RenderX Mikolasek et al JMIR CANCER logging the exercise use for each patient over the course of 20 weeks. Therefore, data on using the app exercises were not biased through self-report. Another advantage of this study was the use of a mixed methods approach, which is recommended for the development of digital interventions [54]. helpful addition to standard care, but as described earlier, they also stated barriers to the implementation of such an intervention, which should be investigated in future studies. Future studies could also investigate an mHealth intervention with more content than in this study app, as suggested during the interviews by health professionals. For instance, audio files with background music or exercises with variations in their duration could be added. In addition to mindfulness and relaxation exercises, physical exercise programs could be added. Physical exercise can have beneficial effects on symptoms of patients with cancer [56], and physical exercise has already been implemented in mHealth apps for patients with cancer [57]. A limitation of the study is that we did not have a control group. Therefore, the effectiveness of the app cannot be determined in this study because regression to the mean could have an impact on the improvement of well-being. Furthermore, we used paper-and-pencil questionnaires, which might have led to more missing data compared with web-based questionnaires [55]. However, this was compensated by using LMM analyses, which take into account all patients who provided baseline data. Another limitation is that we did not assess whether patients were practicing mindfulness and relaxation exercises without the app, which could have an effect on the assessed outcomes. Conclusions The results of this observational feasibility study indicate that a mindfulness and relaxation app can be a feasible and an effective way to deliver a self-care intervention for patients with cancer. Our results indicate that such an intervention might be especially beneficial for highly distressed patients with cancer. The appeal of such an app could be increased with more diverse content, which might also positively affect the adherence of patients to such an intervention. The effectiveness and further aspects regarding the implementation of such an mHealth intervention should be investigated in a future randomized controlled trial. Therefore, future studies should investigate this topic with a randomized controlled trial to determine the effectiveness of a mindfulness and relaxation mHealth intervention. Our study provides some insights regarding the effects that might be expected in a similar study, which will be helpful to power future studies sufficiently. We also looked at aspects of implementing an mHealth intervention. All interviewed health professionals perceived such an mHealth intervention as a JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 11 (page number not for citation purposes) References 1. Mehnert A, Brähler E, Faller H, Härter M, Keller M, Schulz H, et al. Four-week prevalence of mental disorders in patients with cancer across major tumor entities. J Clin Oncol 2014 Nov 01;32(31):3540-3546. [doi: 10.1200/JCO.2014.56.0086] [Medline: 25287821] 2. Mehnert A, Hartung TJ, Friedrich M, Vehling S, Brähler E, Härter M, et al. One in two cancer patients is significantly distressed: prevalence and indicators of distress. Psychooncology 2018 Jan;27(1):75-82. [doi: 10.1002/pon.4464] [Medline: 28568377] ] 3. Vehling S, Koch U, Ladehoff N, Schön G, Wegscheider K, Heckl U, et al. Prevalence of affective and anxiety disorders in cancer: systematic literature review and meta-analysis]. Psychother Psychosom Med Psychol 2012 Jul;62(7):249-258. [doi: 10.1055/s-0032-1309032] [Medline: 22585582] 3. Vehling S, Koch U, Ladehoff N, Schön G, Wegscheider K, Heckl U, et al. Prevalence of affective and anxiety disorders in cancer: systematic literature review and meta-analysis]. Psychother Psychosom Med Psychol 2012 Jul;62(7):249-258. [doi: 10.1055/s-0032-1309032] [Medline: 22585582] 4. Renovanz M, Soebianto S, Tsakmaklis H, Keric N, Nadji-Ohl M, Beutel M, et al. Evaluation of the psychological burden during the early disease trajectory in patients with intracranial tumors by the ultra-brief Patient Health Questionnaire for Depression and Anxiety (PHQ-4). Support Care Cancer 2019 Dec;27(12):4469-4477. [doi: 10.1007/s00520-019-04718-z] [Medline: 30904948] 4. Renovanz M, Soebianto S, Tsakmaklis H, Keric N, Nadji-Ohl M, Beutel M, et al. Evaluation of the psychological burden during the early disease trajectory in patients with intracranial tumors by the ultra-brief Patient Health Questionnaire for Depression and Anxiety (PHQ-4). Support Care Cancer 2019 Dec;27(12):4469-4477. [doi: 10.1007/s00520-019-04718-z] [Medline: 30904948] 5. Burg MA, Adorno G, Lopez ED, Loerzel V, Stein K, Wallace C, et al. Current unmet needs of cancer survivors: analysis of open-ended responses to the American Cancer Society Study of Cancer Survivors II. Cancer 2015 Feb 15;121(4):623-630. [doi: 10.1002/cncr.28951] [Medline: 25581252] 5. Burg MA, Adorno G, Lopez ED, Loerzel V, Stein K, Wallace C, et al. Current unmet needs of cancer survivors: analysis of open-ended responses to the American Cancer Society Study of Cancer Survivors II. Cancer 2015 Feb 15;121(4):623-630. [doi: 10.1002/cncr.28951] [Medline: 25581252] 6. Faller H, Weis J, Koch U, Brähler E, Härter M, Keller M, et al. Utilization of professional psychological care in a large German sample of cancer patients. Psychooncology 2017 Apr;26(4):537-543. [doi: 10.1002/pon.4197] [Medline: 27327213] 6. Faller H, Weis J, Koch U, Brähler E, Härter M, Keller M, et al. Utilization of professional psychological care in a large German sample of cancer patients. References Psychooncology 2017 Apr;26(4):537-543. [doi: 10.1002/pon.4197] [Medline: 27327213] 7. Carlson LE, Zelinski E, Toivonen K, Flynn M, Qureshi M, Piedalue K, et al. Mind-body therapies in cancer: what is the latest evidence? Curr Oncol Rep 2017 Aug 18;19(10):67. [doi: 10.1007/s11912-017-0626-1] [Medline: 28822063] 8. Astin JA, Shapiro SL, Eisenberg DM, Forys KL. Mind-body medicine: state of the science, implications for practice. J Am Board Fam Pract 2003;16(2):131-147 [FREE Full text] [Medline: 12665179] p p y gy p ( ) p 7. Carlson LE, Zelinski E, Toivonen K, Flynn M, Qureshi M, Piedalue K, et al. Mind-body therapies in cancer: what is the latest evidence? Curr Oncol Rep 2017 Aug 18;19(10):67. [doi: 10.1007/s11912-017-0626-1] [Medline: 28822063] 7. Carlson LE, Zelinski E, Toivonen K, Flynn M, Qureshi M, Piedalue K, et al. Mind-body therapies in cancer: what is the latest evidence? Curr Oncol Rep 2017 Aug 18;19(10):67. [doi: 10.1007/s11912-017-0626-1] [Medline: 28822063] 8. Astin JA, Shapiro SL, Eisenberg DM, Forys KL. Mind-body medicine: state of the science, implications for practice. J Am Board Fam Pract 2003;16(2):131-147 [FREE Full text] [Medline: 12665179] 8. Astin JA, Shapiro SL, Eisenberg DM, Forys KL. Mind-body medicine: state of the science, implications for practice. J Am Board Fam Pract 2003;16(2):131-147 [FREE Full text] [Medline: 12665179] JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 11 (page number not for citation purposes) https://cancer.jmir.org/2021/1/e16785 XSL•FO RenderX JMIR CANCER Effects of yoga on psychologic function and quality of life in women with breast cancer: a meta-analysis of randomized controlled trials. J Altern Complement Med 2012 Nov;18(11):994-1002. [doi: 10.1089/acm.2011.0514] [Medline: 22909345] 15. Spahn G, Choi K, Kennemann C, Lüdtke R, Franken U, Langhorst J, et al. Can a multimodal mind-body program enhance the treatment effects of physical activity in breast cancer survivors with chronic tumor-associated fatigue? A randomized controlled trial. Integr Cancer Ther 2013 Jul;12(4):291-300. [doi: 10.1177/1534735413492727] [Medline: 23766391] g 16. Paul A, Cramer H, Lauche R, Altner N, Langhorst J, Dobos GJ. An oncology mind-body medicine day care clinic: concept and case presentation. Integr Cancer Ther 2013 Nov;12(6):503-507. [doi: 10.1177/1534735412473639] [Medline: 23329568] 17. Brebach R, Sharpe L, Costa DSJ, Rhodes P, Butow P. Psychological intervention targeting distress for cancer patients: a meta-analytic study investigating uptake and adherence. Psychooncology 2016 Aug;25(8):882-890. [doi: 10.1002/pon.4099] [Medline: 26893285] 18. Cohen A, Ianovski LE, Frenkiel S, Hier M, Zeitouni A, Kost K, et al. Barriers to psychosocial oncology service utilization in patients newly diagnosed with head and neck cancer. Psychooncology 2018 Dec;27(12):2786-2793. [doi: 10.1002/pon.4889] [Medline: 30216594] 19. Dilworth S, Higgins I, Parker V, Kelly B, Turner J. Patient and health professional's perceived barriers to the delivery of psychosocial care to adults with cancer: a systematic review. Psychooncology 2014 Jun;23(6):601-612. [doi: 10.1002/pon.3474] [Medline: 24519814] 20. Brown LF, Kroenke K, Theobald DE, Wu J, Tu W. The association of depression and anxiety with health-related quality of life in cancer patients with depression and/or pain. Psychooncology 2010 Jul;19(7):734-741 [FREE Full text] [doi: 10.1002/pon.1627] [Medline: 19777535] 21. Berry DL, Blonquist TM, Hong F, Halpenny B, Partridge AH. Self-reported adherence to oral cancer therapy: relationships with symptom distress, depression, and personal characteristics. Patient Prefer Adherence 2015;9:1587-1592 [FREE Full text] [doi: 10.2147/PPA.S91534] [Medline: 26604712] 22. Arcury TA, Gesler WM, Preisser JS, Sherman J, Spencer J, Perin J. The effects of geography and spatial behavior on health care utilization among the residents of a rural region. Health Serv Res 2005 Feb;40(1):135-155 [FREE Full text] [doi: 10.1111/j.1475-6773.2005.00346.x] [Medline: 15663706] j 23. Ensor T, Cooper S. Overcoming barriers to health service access: influencing the demand side. Health Policy Plan 2004 Mar;19(2):69-79. [Medline: 14982885] 24. Waller A, Williams A, Groff SL, Bultz BD, Carlson LE. Screening for distress, the sixth vital sign: examining self-referral in people with cancer over a one-year period. Psychooncology 2013 Feb;22(2):388-395. [doi: 10.1002/pon.2102] [Medline: 22135205] 25. Eysenbach G. JMIR CANCER JMIR CANCER Mikolasek et al 9. Kwekkeboom KL, Cherwin CH, Lee JW, Wanta B. Mind-body treatments for the pain-fatigue-sleep disturbance symptom cluster in persons with cancer. J Pain Symptom Manage 2010 Jan;39(1):126-138 [FREE Full text] [doi: 10.1016/j.jpainsymman.2009.05.022] [Medline: 19900778] j jp y 10. Cramer H, Lauche R, Klose P, Lange S, Langhorst J, Dobos GJ. Yoga for improving health-related quality of life, mental health and cancer-related symptoms in women diagnosed with breast cancer. Cochrane Database Syst Rev 2017 Jan 03;1:CD010802 [FREE Full text] [doi: 10.1002/14651858.CD010802.pub2] [Medline: 28045199] p 11. Haller H, Winkler MM, Klose P, Dobos G, Kümmel S, Cramer H. Mindfulness-based interventions for women with breast cancer: an updated systematic review and meta-analysis. Acta Oncol 2017 Dec;56(12):1665-1676. [doi: 10.1080/0284186X.2017.1342862] [Medline: 28686520] p 11. Haller H, Winkler MM, Klose P, Dobos G, Kümmel S, Cramer H. Mindfulness-based interventions for women with breast cancer: an updated systematic review and meta-analysis. Acta Oncol 2017 Dec;56(12):1665-1676. [doi: 10.1080/0284186X.2017.1342862] [Medline: 28686520] 12. Chen Z, Meng Z, Milbury K, Bei W, Zhang Y, Thornton B, et al. Qigong improves quality of life in women undergoing radiotherapy for breast cancer: results of a randomized controlled trial. Cancer 2013 May 01;119(9):1690-1698 [FREE Full text] [doi: 10.1002/cncr.27904] [Medline: 23355182] 12. Chen Z, Meng Z, Milbury K, Bei W, Zhang Y, Thornton B, et al. Qigong improves quality of life in women undergoing radiotherapy for breast cancer: results of a randomized controlled trial. Cancer 2013 May 01;119(9):1690-1698 [FREE Full text] [doi: 10.1002/cncr.27904] [Medline: 23355182] 13. Jeitler M, Jaspers J, von Scheidt C, Koch B, Michalsen A, Steckhan N, et al. Mind-body medicine and lifestyle modification in supportive cancer care: a cohort study on a day care clinic program for cancer patients. Psychooncology 2017 Dec;26(12):2127-2134. [doi: 10.1002/pon.4433] [Medline: 28370730] 13. Jeitler M, Jaspers J, von Scheidt C, Koch B, Michalsen A, Steckhan N, et al. Mind-body medicine and lifestyle modification in supportive cancer care: a cohort study on a day care clinic program for cancer patients. Psychooncology 2017 Dec;26(12):2127-2134. [doi: 10.1002/pon.4433] [Medline: 28370730] p 14. Zhang J, Yang K, Tian J, Wang C. Effects of yoga on psychologic function and quality of life in women with breast cancer: a meta-analysis of randomized controlled trials. J Altern Complement Med 2012 Nov;18(11):994-1002. [doi: 10.1089/acm.2011.0514] [Medline: 22909345] 14. Zhang J, Yang K, Tian J, Wang C. JMIR CANCER Fischer F, Gibbons C, Coste J, Valderas JM, Rose M, Leplège A. Measurement invariance and general population reference values of the PROMIS Profile 29 in the UK, France, and Germany. Qual Life Res 2018 Apr;27(4):999-1014. [doi: 10.1007/s11136-018-1785-8] [Medline: 29350345] 38. Fischer F, Gibbons C, Coste J, Valderas JM, Rose M, Leplège A. Measurement invariance and general population reference values of the PROMIS Profile 29 in the UK, France, and Germany. Qual Life Res 2018 Apr;27(4):999-1014. [doi: 10.1007/s11136-018-1785-8] [Medline: 29350345] 39. Bonomi AE, Cella DF, Hahn EA, Bjordal K, Sperner-Unterweger B, Gangeri L, et al. Multilingual translation of the Functional Assessment of Cancer Therapy (FACT) quality of life measurement system. Qual Life Res 1996 Jun;5(3):309-320. [doi: 10.1007/bf00433915] [Medline: 8763799] 40. Cella DF, Tulsky DS, Gray G, Sarafian B, Linn E, Bonomi A, et al. The Functional Assessment of Cancer Therapy scale: development and validation of the general measure. J Clin Oncol 1993 Mar;11(3):570-579. [doi: 10.1200/JCO.1993.11.3.570] [Medline: 8445433] 41. Mehnert A, Müller D, Lehmann C, Koch U. [Die deutsche Version des NCCN Distress-Thermometers]. Z Psychol Psychiatr Psychother 2006 Jan;54(3):213-223. [doi: 10.1024/1661-4747.54.3.213] 42. Jacobsen PB, Donovan KA, Trask PC, Fleishman SB, Zabora J, Baker F, et al. Screening for psychologic distress in ambulatory cancer patients. Cancer 2005 Apr 01;103(7):1494-1502 [FREE Full text] [doi: 10.1002/cncr.20940] [Medline: 15726544] ] 43. Walach H, Buchheld N, Buttenmüller V, Kleinknecht N, Schmidt S. Measuring mindfulness—the Freiburg Mindfulness Inventory (FMI). Pers Individ Dif 2006 Jun;40(8):1543-1555. [doi: 10.1016/j.paid.2005.11.025] 44. Snaith RP. The hospital anxiety and depression scale. Health Qual Life Outcomes 2003;1:29 [FREE Full text] [doi: 10 1186/1477 7525 1 29] [M dli 12914662] ] 43. Walach H, Buchheld N, Buttenmüller V, Kleinknecht N, Schmidt S. Measuring mindfulness—the Freiburg Mindfulness Inventory (FMI). Pers Individ Dif 2006 Jun;40(8):1543-1555. [doi: 10.1016/j.paid.2005.11.025] Inventory (FMI). Pers Individ Dif 2006 Jun;40(8):1543-1555. [doi: 10.1016/j.paid.2005.11.025] 44. Snaith RP. The hospital anxiety and depression scale. Health Qual Life Outcomes 2003;1:29 [FREE Full text] [doi: 10.1186/1477-7525-1-29] [Medline: 12914662] 44. Snaith RP. The hospital anxiety and depression scale. Health Qual Life Outcomes 2003;1:29 [FREE Full text] [doi: 10.1186/1477-7525-1-29] [Medline: 12914662] 45. Mehnert A, Herschbach P, Berg P, Henrich G, Koch U. [Fear of progression in breast cancer patients--validation of the short form of the Fear of Progression Questionnaire (FoP-Q-SF)]. Z Psychosom Med Psychother 2006;52(3):274-288. [doi: 10.13109/zptm.2006.52.3.274] [Medline: 17156600] p 46. Mayring P. Qualitative Inhaltsanalyse: Grundlagen und Techniken. Basel: Beltz Pädagogik; 2010. 47. JMIR CANCER Lengacher CA, Reich RR, Ramesar S, Alinat CB, Moscoso M, Cousin L, et al. Feasibility of the mobile mindfulness-based stress reduction for breast cancer (mMBSR(BC)) program for symptom improvement among breast cancer survivors. Psychooncology 2018 Feb;27(2):524-531. [doi: 10.1002/pon.4491] [Medline: 28665541] 48. Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [doi: 10.1177/1534735419850634] [Medline: 31092044] 48. Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [doi: 10.1177/1534735419850634] [Medline: 31092044] 49. Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug;27(8):2023-2030. [doi: 10.1002/pon.4764] [Medline: 29766596] 49. Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug;27(8):2023-2030. [doi: 10.1002/pon.4764] [Medline: 29766596] 50. Barth J, Delfino S, Künzler A. Naturalistic study on the effectiveness of psycho-oncological interventions in cancer patients and their partners. Support Care Cancer 2013 Jun;21(6):1587-1595. [doi: 10.1007/s00520-012-1700-8] [Medline: 23299560] 50. Barth J, Delfino S, Künzler A. Naturalistic study on the effectiveness of psycho-oncological interventions in cancer patients and their partners. Support Care Cancer 2013 Jun;21(6):1587-1595. [doi: 10.1007/s00520-012-1700-8] [Medline: 23299560] 51. Bishop FL, Lewith GT. Who uses CAM? A narrative review of demographic characteristics and health factors associated with CAM use. Evid Based Complement Alternat Med 2010 Mar;7(1):11-28 [FREE Full text] [doi: 10.1093/ecam/nen023] [M dli 18955327] 50. Barth J, Delfino S, Künzler A. Naturalistic study on the effectiveness of psycho-oncological interventions in cancer patients and their partners. Support Care Cancer 2013 Jun;21(6):1587-1595. [doi: 10.1007/s00520-012-1700-8] [Medline: 23299560] 51 Bishop FL Lewith GT Who uses CAM? A narrative review of demographic characteristics and health factors associated and their partners. Support Care Cancer 2013 Jun;21(6):1587 1595. [doi: 10.1007/s00520 012 1700 8] [Medline: 23299560] 51. Bishop FL, Lewith GT. Who uses CAM? JMIR CANCER What is e-health? J Med Internet Res 2001 Jun;3(2):E20. [doi: 10.2196/jmir.3.2.e20] [Medline: 11720962] 25. Eysenbach G. What is e-health? J Med Internet Res 2001 Jun;3(2):E20. [doi: 10.2196/jmir.3.2.e20] [Medline: 11720962] 26 van Heerden A Tomlinson M Swartz L Point of care in your pocket: a research agenda for the field of m health Bull y j 26. van Heerden A, Tomlinson M, Swartz L. Point of care in your pocket: a research agenda for the fie World Health Organ 2012 May 1;90(5):393-394 [FREE Full text] [doi: 10.2471/BLT.11.099788] [M 27. Mikolasek M, Berg J, Witt CM, Barth J. Effectiveness of mindfulness- and relaxation-based eHealth interventions for patients with medical conditions: a systematic review and synthesis. Int J Behav Med 2017 Jul 27. [doi: 10.1007/s12529-017-9679-7] [Medline: 28752414] 28. Fish J, Brimson J, Lynch S. Mindfulness interventions delivered by technology without facilitator involvement: what research exists and what are the clinical outcomes? Mindfulness (N Y) 2016;7(5):1011-1023 [FREE Full text] [doi: 10.1007/s12671-016-0548-2] [Medline: 27642370] 28. Fish J, Brimson J, Lynch S. Mindfulness interventions delivered by technology without facilitator involvement: what research exists and what are the clinical outcomes? Mindfulness (N Y) 2016;7(5):1011-1023 [FREE Full text] [doi: 10.1007/s12671-016-0548-2] [Medline: 27642370] 29. Spijkerman MP, Pots WT, Bohlmeijer ET. Effectiveness of online mindfulness-based interventions in improving mental health: a review and meta-analysis of randomised controlled trials. Clin Psychol Rev 2016 Apr;45:102-114 [FREE Full text] [doi: 10.1016/j.cpr.2016.03.009] [Medline: 27111302] 29. Spijkerman MP, Pots WT, Bohlmeijer ET. Effectiveness of online mindfulness-based interventions in improving mental health: a review and meta-analysis of randomised controlled trials. Clin Psychol Rev 2016 Apr;45:102-114 [FREE Full text] [doi: 10.1016/j.cpr.2016.03.009] [Medline: 27111302] JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 12 (page number not for citation purposes) https://cancer.jmir.org/2021/1/e16785 JMIR CANCER JMIR CANCER Mikolasek et al 30. McAlpine H, Joubert L, Martin-Sanchez F, Merolli M, Drummond KJ. A systematic review of types and efficacy of online interventions for cancer patients. Patient Educ Couns 2015 Mar;98(3):283-295. [doi: 10.1016/j.pec.2014.11.002] [Medline: 25535016] 31. Escriva Boulley G, Leroy T, Bernetière C, Paquienseguy F, Desfriches-Doria O, Préau M. Digital health interventions to help living with cancer: a systematic review of participants' engagement and psychosocial effects. Psychooncology 2018 Dec;27(12):2677-2686. [doi: 10.1002/pon.4867] [Medline: 30152074] ( ) [ p ] [ ] 32. Tomlinson M, Rotheram-Borus MJ, Swartz L, Tsai AC. Scaling up mHealth: where is the evidence? PLoS Med 2013;10(2):e1001382 [FREE Full text] [doi: 10.1371/journal.pmed.1001382] [Medline: 23424286] 32. Tomlinson M, Rotheram-Borus MJ, Swartz L, Tsai AC. Scaling up mHealth: where is the evidence? PLoS Med 2013;10(2):e1001382 [FREE Full text] [doi: 10.1371/journal.pmed.1001382] [Medline: 23424286] 33. Matthew-Maich N, Harris L, Ploeg J, Markle-Reid M, Valaitis R, Ibrahim S, et al. Designing, implementing, and evaluating mobile health technologies for managing chronic conditions in older adults: a scoping review. JMIR Mhealth Uhealth 2016 Jun 09;4(2):e29 [FREE Full text] [doi: 10.2196/mhealth.5127] [Medline: 27282195] 34. Gagnon M, Ngangue P, Payne-Gagnon J, Desmartis M. m-Health adoption by healthcare professionals: a systematic review. J Am Med Inform Assoc 2016 Jan;23(1):212-220. [doi: 10.1093/jamia/ocv052] [Medline: 26078410] j 35. Zhao Y, Ni Q, Zhou R. What factors influence the mobile health service adoption? A meta-analysi role of age. Int J Inf Manage 2018 Dec;43:342-350. [doi: 10.1016/j.ijinfomgt.2017.08.006] 36. Mikolasek M, Witt CM, Barth J. Adherence to a mindfulness and relaxation self-care app for cancer patients: mixed-methods feasibility study. JMIR Mhealth Uhealth 2018 Dec 06;6(12):e11271 [FREE Full text] [doi: 10.2196/11271] [Medline: 30522990] 37. Glasgow RE, Vogt TM, Boles SM. Evaluating the public health impact of health promotion interventions: the RE-AIM framework. Am J Public Health 1999 Sep;89(9):1322-1327. [doi: 10.2105/ajph.89.9.1322] [Medline: 10474547] 37. Glasgow RE, Vogt TM, Boles SM. Evaluating the public health impact of health promotion interventions: the RE-AIM framework. Am J Public Health 1999 Sep;89(9):1322-1327. [doi: 10.2105/ajph.89.9.1322] [Medline: 10474547] 38. Fischer F, Gibbons C, Coste J, Valderas JM, Rose M, Leplège A. Measurement invariance and general population reference values of the PROMIS Profile 29 in the UK France and Germany Qual Life Res 2018 Apr;27(4):999 1014 [doi: 37. Glasgow RE, Vogt TM, Boles SM. Evaluating the public health impact of health promotion interventions: the RE AIM framework. Am J Public Health 1999 Sep;89(9):1322-1327. [doi: 10.2105/ajph.89.9.1322] [Medline: 10474547] 38. JMIR CANCER Integr Cancer Ther 2018 Dec;17(4):1048-1058 [FREE Full text] [doi: 10.1177/1534735418807555] [Medline: 30352523] 57. Haberlin C, O'Dwyer T, Mockler D, Moran J, O'Donnell DM, Broderick J. The use of eHealth to promote physical activity in cancer survivors: a systematic review. Support Care Cancer 2018 Jun 16. [doi: 10.1007/s00520-018-4305-z] [Medline: 29909476] 57. Haberlin C, O'Dwyer T, Mockler D, Moran J, O'Donnell DM, Broderick J. The use of eHealth to promote physical activity in cancer survivors: a systematic review. Support Care Cancer 2018 Jun 16. [doi: 10.1007/s00520-018-4305-z] [Medline: 29909476] JMIR CANCER A narrative review of demographic characteristics and health factors associated with CAM use. Evid Based Complement Alternat Med 2010 Mar;7(1):11-28 [FREE Full text] [doi: 10.1093/ecam/nen023] [Medline: 18955327] 51. Bishop FL, Lewith GT. Who uses CAM? A narrative review of demographic characteristics and health factors associated with CAM use. Evid Based Complement Alternat Med 2010 Mar;7(1):11-28 [FREE Full text] [doi: 10.1093/ecam/nen023] [Medline: 18955327] JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 13 (page number not for citation purposes) https://cancer.jmir.org/2021/1/e16785 JMIR CANCER JMIR CANCER Mikolasek et al 52. Reid R, Steel A, Wardle J, Trubody A, Adams J. Complementary medicine use by the Australian population: a critical mixed studies systematic review of utilisation, perceptions and factors associated with use. BMC Complement Altern Med 2016 Jun 11;16:176 [FREE Full text] [doi: 10.1186/s12906-016-1143-8] [Medline: 27289517] 52. Reid R, Steel A, Wardle J, Trubody A, Adams J. Complementary medicine use by the Australian population: a critical mixed studies systematic review of utilisation, perceptions and factors associated with use. BMC Complement Altern Med 2016 Jun 11;16:176 [FREE Full text] [doi: 10.1186/s12906-016-1143-8] [Medline: 27289517] 53. Thomson P, Jones J, Evans JM, Leslie SL. Factors influencing the use of complementary and alternative medicine and whether patients inform their primary care physician. Complement Ther Med 2012;20(1-2):45-53. [doi: 10.1016/j.ctim.2011.10.001] [Medline: 22305248] 53. Thomson P, Jones J, Evans JM, Leslie SL. Factors influencing the use of complementary and alternative medicine and whether patients inform their primary care physician. Complement Ther Med 2012;20(1-2):45-53. [doi: 10.1016/j.ctim.2011.10.001] [Medline: 22305248] j ] [ ] 54. Michie S, Yardley L, West R, Patrick K, Greaves F. Developing and evaluating digital interventions to promote behavior change in health and health care: recommendations resulting from an international workshop. J Med Internet Res 2017 Jun 29;19(6):e232 [FREE Full text] [doi: 10.2196/jmir.7126] [Medline: 28663162] 54. Michie S, Yardley L, West R, Patrick K, Greaves F. Developing and evaluating digital interventions to promote behavior change in health and health care: recommendations resulting from an international workshop. J Med Internet Res 2017 Jun 29;19(6):e232 [FREE Full text] [doi: 10.2196/jmir.7126] [Medline: 28663162] 55. Kongsved SM, Basnov M, Holm-Christensen K, Hjollund NH. Response rate and completeness of questionnaires: a randomized study of internet versus paper-and-pencil versions. J Med Internet Res 2007;9(3):e25 [FREE Full text] [doi: 10.2196/jmir.9.3.e25] [Medline: 17942387] 55. Kongsved SM, Basnov M, Holm-Christensen K, Hjollund NH. Response rate and completeness of questionnaires: a randomized study of internet versus paper-and-pencil versions. J Med Internet Res 2007;9(3):e25 [FREE Full text] [doi: 10.2196/jmir.9.3.e25] [Medline: 17942387] j 56. Nakano J, Hashizume K, Fukushima T, Ueno K, Matsuura E, Ikio Y, et al. Effects of aerobic and resistance exercises on physical symptoms in cancer patients: a meta-analysis. Integr Cancer Ther 2018 Dec;17(4):1048-1058 [FREE Full text] [doi: 10.1177/1534735418807555] [Medline: 30352523] 56. Nakano J, Hashizume K, Fukushima T, Ueno K, Matsuura E, Ikio Y, et al. Effects of aerobic and resistance exercises on physical symptoms in cancer patients: a meta-analysis. Abbreviations Edited by G Eysenbach; submitted 27.10.19; peer-reviewed by E Børøsund, K Rosen; comments to author 20.01.20; revis received 13.03.20; accepted 18.11.20; published 13.01.21 Please cite as: Mikolasek M, Witt CM, Barth J Effects and Implementation of a Mindfulness and Relaxation App for Patients With Cancer: Mixed Methods Feasibility Study JMIR Cancer 2021;7(1):e16785 URL: https://cancer.jmir.org/2021/1/e16785 doi: 10.2196/16785 PMID: 33439132 ©Michael Mikolasek, Claudia Margitta Witt, Jürgen Barth. Originally published in JMIR Cancer (http://cancer.jmir.org), 13.01.2021. This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in JMIR Cancer, is properly cited. The complete bibliographic information, a link to the original publication on http://cancer.jmir.org/, as well as this copyright and license information must be included. JMIR Cancer 2021 | vol. 7 | iss. 1 | e16785 | p. 14 (page number not for citation purposes) https://cancer.jmir.org/2021/1/e16785 https://cancer.jmir.org/2021/1/e16785 XSL•FO RenderX XSL•FO RenderX
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Anti-Inflammatory Action of Dietary Wild Olive (Acebuche) Oil in the Retina of Hypertensive Mice
Foods
2,021
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Article Anti-Inflammatory Action of Dietary Wild Olive (Acebuche) Oil in the Retina of Hypertensive Mice Álvaro Santana-Garrido 1,2 , Claudia Reyes-Goya 1, Santiago Milla-Navarro 3 , Pedro de la Villa 3,4, Helder André 5 , Carmen M. Vázquez 1,2 and Alfonso Mate 1,2,* ntana-Garrido 1,2 , Claudia Reyes-Goya 1, Santiago Milla-Navarro 3 , Pedro de la Villa 3,4, ndré 5 , Carmen M. Vázquez 1,2 and Alfonso Mate 1,2,* 1 Departamento de Fisiología, Facultad de Farmacia, Universidad de Sevilla, 41012 Sevilla, Spain; asgarrido@us.es (Á.S.-G.); crgoya@us.es (C.R.-G.); vazquez@us.es (C.M.V.) g g y q 2 Epidemiología Clínica y Riesgo Cardiovascular, Instituto de Biomedicina de Sevilla (IBIS), Hospital Universitario Virgen del Rocío/Consejo Superior de Investigaciones Científicas/ Universidad de Sevilla, 41013 Sevilla, Spain p 3 Department of Systems Biology, University of Alcalá, 28871 Madrid, Spain; santiago milla@edu uah es (S M N ); pedro villa@uah es (Pd l V) p 3 Department of Systems Biology, University of Alcalá, 28871 Madrid, Spain; santiago.milla@edu.uah.es (S.M.-N.); pedro.villa@uah.es (P.d.l.V.) g ( ) p ( ) 4 Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), 28034 Madrid, Spain 4 Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), 28034 Madrid, Spain 5 D f Cli i l N i S E ik E H i l K li k I i 11282 S kh l S d 5 Department of Clinical Neuroscience, St. Erik Eye Hospital, Karolinska Institutet, 11282 Stockholm, Sweden; helder.andre@ki.se 5 Department of Clinical Neuroscience, St. Erik Eye Hospital, Karolinska Institutet, 11282 Stockholm, Sweden helder.andre@ki.se * Correspondence: mate@us.es Abstract: Inflammation plays a crucial role in the course of eye diseases, including many vascular retinopathies. Although olive oil is known to have beneficial effects against inflammatory processes, there is no information available on the anti-inflammatory potential of the wild olive tree (namely, acebuche (ACE) for the primitive Spanish lineages). Here we investigate the anti-inflammatory effects of ACE oil in the retina of a mouse model of arterial hypertension, which was experimentally induced by administration of L-NAME (NG-nitro-L-arginine-methyl-ester). The animals were fed supplements of ACE oil or extra virgin olive oil (EVOO, for comparative purposes). Retinal function was assessed by electroretinography (ERG), and different inflammation-related parameters were measured in the retina and choroid. Besides significant prevention of retinal dysfunction shown in ERG recordings, ACE oil-enriched diet upregulated the expression of the anti-inflammatory markers PPARγ, PPARα and IL-10, while reducing that of major proinflammatory biomarkers, IL-1β, IL-6, TNF-α and COX-2.   Citation: Santana-Garrido, Á.; Reyes-Goya, C.; Milla-Navarro, S.; de la Villa, P.; André, H.; Vázquez, C.M.; Mate, A. Anti-Inflammatory Action of Dietary Wild Olive (Acebuche) Oil in the Retina of Hypertensive Mice. Foods 2021, 10, 1993. https://doi.org/ 10.3390/foods10091993 Academic Editors: Ruth Hornedo- Ortega and Ana B. Cerezo Keywords: acebuche; arterial hypertension; inflammation; olive oil; retina; wild olive tree Received: 26 July 2021 Accepted: 23 August 2021 Published: 25 August 2021 foods foods Article Anti-Inflammatory Action of Dietary Wild Olive (Acebuche) Oil in the Retina of Hypertensive Mice This is the first report to highlight the anti-inflammatory properties of an ACE oil-enriched diet against hypertension-related retinal damage. Noteworthy, dietary supplementation with ACE oil yielded better results compared to a reference EVOO. 1. Introduction Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Numerous authors have recognized the pivotal role of extra virgin olive oil (EVOO) (Olea europaea L.) in the context of the well-known Mediterranean diet, and the potential benefits of its multiple bioactive compounds [1,2]. In this sense, EVOO has been identified as a key to reducing the risk of various diseases [3–5]. The beneficial health outcomes derived from the regular consumption of olive oil rely on its nutritional components to which antioxidant, anti-inflammatory and antitumoral properties are ascribed. y p p The major constituents of EVOO include acyclglycerols, free fatty acids, pigments and phosphatides, among others. A high proportion of monounsaturated fats also defines its distinctive biochemical profile [6], of which oleic acid (C18:1) is probably the most studied [7]. Polyunsaturated fatty acids (PUFAs) include linoleic (C18:2) and α-linolenic (C18:3) acids, whereas saturated fatty acids (SFA) account only for 8–14% [8]. Interestingly, EVOO also contains a wide range of minor components including sterols, tocopherols, triterpenic and phenolic compounds, which are involved in a profusion of pathways involved in homeostasis, inflammation and redox state [9–12]. Consequently, regular consumption of EVOO has been Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). https://www.mdpi.com/journal/foods Foods 2021, 10, 1993. https://doi.org/10.3390/foods10091993 Foods 2021, 10, 1993 2 of 18 2 of 18 proposed as a powerful nutraceutical tool to avert and mitigate cancer and cardiovascular or degenerative diseases [13,14], where noticeable contributions of hydroxytyrosol and its derivates (tyrosol, oleuropein and oleocanthal) have been reported [15]. Nonetheless, some authors have claimed the need to discover additional minor bioactive components of EVOO that might help understand its beneficial properties. g p p p Unlike the renowned reports concerning the consumption of fruits and oil obtained from the common olive tree (Olea europaea var. europaea) in the setting of the Mediterranean diet, the information available on the wild olive tree (Olea europaea var. sylvestris)—namely, acebuche (ACE) for the primitive Spanish lineages—is very limited. 1. Introduction Thus, although different studies have addressed the composition and therapeutic effects of EVOO, very little is known specifically about ACE oil, a product of growing interest in specific regions such as Andalusia, Spain. The conservation of genuine wild olive lineages is desirable from an environmental point of view; however, these olive varieties have remained largely under-exploited, because the fruit of the wild olive yields little oil compared to cultivated olives. Therefore, the small amounts of commercially available ACE oil are typically consumed as “gourmet” products that are generally recognized as spicier, more bitter and fruitier than standard EVOOs, possibly due to slight differences in minor compounds [16,17]. Some of the first evidences have attributed a higher content of tocopherols (e.g., vitamin E), sterols and triterpene acids in ACE oil than in EVOO, and also a higher amount of secoiridoid compounds relative to ortodiphenols in the former [18,19]. Moreover, ACE oil has been reported to have lower antigenic and allergenic capacities compared to cultivated olive trees [20]. g g p p Despite the importance of EVOO in protecting against cardiovascular diseases (CV), its potential role as a bioactive supplement able to counteract the development/progression of ocular diseases is not well established yet. Previous population studies have suggested that EVOO might be useful to delay the occurrence of age-related macular degenera- tion (AMD) [21–23], while in vivo and in vitro experiments described neuronal protec- tion of EVOO components (e.g., hydroxytyrosol and oleuropein) in diabetic retinopathy (DR) [24–27]. In this regard, we have recently demonstrated a retinoprotective action of EVOO- and ACE oil-enriched diets, showing better results in the latter case, in a context of arterial hypertension (AH). The beneficial actions of these oils were ascribed to their capacity to counteract the progression of hypertensive eye disease by reducing superoxide anions (O2·−) and by modulating the enzymes NADPH oxidase and nitric oxide synthase, among others [19]. Therefore, ACE oil and EVOO-based diets could represent a strategical tool to reduce AH-related ocular damage in pathologies such AMD, DR or hypertensive retinopathy, among others. However, knowing the precise mechanisms responsible for the beneficial properties of olive oil consumption at the ocular level requires further research. p p p q Along with oxidative stress, inflammation has been extensively studied as a key mech- anism in the pathogenesis of hypertension, especially in the context of persistent AH [28,29]. 1. Introduction The expression of major inflammatory biomarkers, including tumor necrosis factor-alpha (TNF-α) [30], cyclooxygenase-2 (COX-2) [31] and interleukin (IL) isoforms [32], is known to be modulated during the course of AH. In addition, it is well known that low-grade inflammation in AH is associated with several pathways involved in the development and progression of different ocular pathologies [33,34], including DR [35], glaucoma [36] and AMD [37], among others. While it is also noteworthy that the literature on the interplay between inflammation and AH supports the involvement of the former in hypertensive retinopathy [38] and DR [39], how hypertension contributes to inflammation and its rel- evance in the development/progression of major retinopathies has not been previously studied. Some of the components of EVOO mentioned above have been postulated as possible contributors to reduce the inflammation process in different diseases, including hydroxytyrosol [40], oleocanthal [41] or triterpenes such as ursolic and oleanolic acids [42], among others. Novel dietary and/or therapeutic strategies could help reduce retinal in- flammation (whether or not related to AH) and describe the possible implication of AH in this regard, thus contributing to unveil hypertension-associated target organ damage. Foods 2021, 10, 1993 3 of 18 3 of 18 The purpose of the current study was to test the ability of an ACE oil-enriched diet to counteract retinal inflammation, based on a plausible anti-inflammatory effect, in a rodent model of AH triggered by chronic administration of L-NAME (NG-nitro-L-arginine-methyl- ester). Visual function was estimated by electroretinography in unconscious hypertensive mice after a 6-week period of ACE oil administration. Moreover, the expression of peroxi- some proliferator-activated receptors (PPARs) and that of inflammation-related biomarkers (namely, interleukin isoforms (IL-1β, IL-6 and IL-10), TNF-α and COX-2) was assayed by immunohistofluorescence in retinal/choroid layers, and by Western blotting and real- time PCR in retinal homogenates. Additional experiments were carried out in parallel substituting EVOO for ACE oil, for comparative analysis. 2.3. Animal Characteristics Systolic and diastolic blood pressure values (SBP, DBP) were recorded every week throughout treatment by the non-invasive, tail-cuff occlusion method in conscious animals by means of a pressure recorder (NIPREM 645, CIBERTEC S.A., Madrid, Spain). Blood pressure values were pooled and averaged from three to four consecutive measurements. 2. Materials and Methods 2.1. Study Design The present study complies with the European Union (EU) Directive 2010/63/EU and the National (RD 53/2013) guidelines for the care and use of Laboratory animals and was approved by the relevant Institutional Animal Care and Use Committee (Dirección General de Producción Agrícola y Ganadería, Junta de Andalucía, reference #13/03/2019/031). 10–12-week-old male C57B/6J mice were supplied by the Center for Animal Production and Experimentation (University of Seville, Spain). The animals were randomly distributed into six groups: (1) Control (standard pellet diet), (2) ACE (standard pellet diet supplemented with 12% (w/w) of wild olive oil), (3) EVOO (standard pellet diet supplemented with 12% of extra virgin olive oil), (4) L-NAME (mice made hypertensive following treatment with 45 mg L-NAME/kg/day), (5) LN + ACE (L-NAME-treated hypertensive mice fed the same diet as in group 2; and (6) LN + EVOO group (L-NAME-treated hypertensive mice fed the same diet as in group 3). All treatments lasted 6 weeks under continuous monitoring of solid and liquid intake. Animals were housed under standard regulated conditions (23 ± 1 ◦C, 12 h/12 h light/dark cycles). 2.2. Dietary Supplementation A commercial rodent chow (ROD14IRR, Sodispan Research, Altromin, Germany) was supplemented with 12% of ACE oil (groups 2 and 5) or EVOO (groups 3 and 6), as mentioned above. The specifications for the preparation of the diets and the chemical composition of ACE oil and EVOO were previously reported [19]. The oil-powder pellets were kept cool and protected from light until daily use. Both oils were produced in Sierra de las Nieves (Málaga, Spain) using exactly the same extraction methods, in accordance with standard protocols to comply with extra virgin olive oil definition. Briefly, oils were obtained by a process of grinding, mixing and extraction at room temperature by centrifugation in a two-phase system. Then, they were kept in an insulated cellar with controlled temperature, protected from light and away from any source of external flavors. The oils were analyzed prior to their use in animal experiments [19]. The required amount of L-NAME in the water bottles was adjusted every week after monitoring each animal’s body weight and water intake; the specific dose was chosen from prior studies performed routinely in our laboratory. 2.5. Sample Harvesting Animals were anesthetized with intraperitoneal injections of ketamine (75 mg/Kg) plus diazepam (10 mg mg/Kg), then subjected to cervical dislocation. The retinas were immediately isolated under a binocular stereo microscope, immersed in liquid nitrogen and maintained at −80 ◦C until use for gene/protein expression analyses. For immunodetection of proteins of interest in retinal/choroidal tissue, eyes were processed as described below (Section 2.8). 2.4. Electroretinography (ERG) Dark-adapted mice (12 h) were anaesthetized, under dim red light, with an intraperi- toneal injection of a mix of ketamine (Ketamidor, Richter Pharma AG, Wels, Austria; 100 mg/mL) and xylazine (Xilagesic, CALIER, Barcelona, Spain; 20 mg/mL) in saline Foods 2021, 10, 1993 4 of 18 solution (NaCl 0.9%), at a final concentration of 0.5 mL/150 g body weight. The animals’ temperature was kept at 37 ◦C with a water-content heating pad, to avoid electric noise during the recording. Pupil dilation was achieved with 1% tropicamide (Alcon Cusí S.A., El Masnou, Barcelona, Spain). A needle was located at the base of the tail for grounding and a reference electrode was placed on the tongue. A gold band electrode was used to record ERGs from the right eye. The electrode was placed on the cornea, and a drop of 2% methyl-cellulose (Methocel 2%, Omnivision, Neuhausen, Switzerland) was placed between the cornea and the electrode to assure electrical conductivity and to protect the eye. y p y Full-field flash ERG was performed with a Ganzfeld dome. Initially, a first scotopic phase was performed with flashes of increasing intensity (−4.0, −3.0, −2.0, −1.5, −1.0, −0.5, −0.0, 0.5, 1.0, and 1.5 log cd·s−1·m−2). The interval between flashes in scotopic conditions ranged from 1.2 s for dim flashes to 15 s for the highest intensity stimuli. ERG signals were amplified and filtered between 0.3 and 1000 Hz with a Grass amplifier (CP511 AC amplifier, Grass Instruments, Quincy, MA, USA, EE.UU.). In general, scotopic b-wave (b-scot) informs about rod-driven circuitry, mixed waves (mixed) indicate rod and cone photoreceptors (a-mix) and their postsynaptic circuitry (b-mix) activity, and photopic b-wave (b-photo) test how photopic conditions affect cone-driven circuitry through rod- saturating light stimulation. Moreover, oscillatory potentials (OP) were isolated using a bright flash (1.5 log cd·s−1·m−2) and band pass filter between 30 and 10,000 Hz. Cone- mediated responses were recorded on a rod-saturating background of 30 cd/m2, after 5 min of adaptation, with flashes of increasing intensity (−1.0, −0.5, −0.0, 0.5, 1.0 and 1.5 log cd·s−1·m−2). Under photopic conditions, the interval between light flashes was fixed at 1.2 s. Flicker (FL) response was recorded at different frequencies (20, 30 and 50 Hz) and an intensity of 1.5 log cd·s−1·m−2. ERG wave components were measured manually using the commercial software LabChart Pro v.8.1.13 (ADInstruments Ltd., Oxfordshire, UK). 2.6. Western Blotting Analyses Retinal homogenates were prepared in protease inhibitor-containing phosphate buffer saline (50 mM PBS, Sigma Aldrich-Roche, Madrid, Spain) using a Potter-Elvehjem tissue grinder. Homogenized samples were centrifuged for 10 min at 10,000× g and aliquots of the corresponding supernatants were set aside to estimate the protein concentration according to the method described by Bradford [43]. Western blotting analyses were performed in retinal homogenates containing 40–50 µg of proteins, as previously described [19]. Specific primary and secondary antibodies are listed in Table 1. Blot signals were quantified by optical densitometry (Cytiva Europe GmbH, Barcelona, Spain), and constitutive β-actin was used as the loading control in all blots. Foods 2021, 10, 1993 5 of 18 Table 1. Antibodies used for Western blotting analysis. SCB = Santa Cruz Biotechnology (Santa Cruz, CA, USA). Primary Antibody Origin Dilution Secondary Antibody Dilution Reference Anti-PPARγ Mouse monoclonal 1:2000 Goat Anti-Mouse 1:4000 SCB Anti-PPARα Mouse monoclonal 1:2000 Goat Anti-Mouse 1:4000 SCB Anti-IL-6 Mouse monoclonal 1:1000 Goat Anti-Rabbit 1:2000 SCB Anti-IL-1β Mouse monoclonal 1:1000 Goat Anti-Mouse 1:2000 SCB Anti-IL-10 Mouse monoclonal 1:1000 Goat Anti-Mouse 1:2000 SCB Anti-TNF-α Mouse monoclonal 1:1000 Goat Anti-Mouse 1:2000 SCB Anti-COX2 Mouse monoclonal 1:1000 Goat Anti-Mouse 1:2000 SCB Anti-β-Actin Mouse monoclonal 1:20,000 Goat Anti-Mouse 1:30,000 SCB dies used for Western blotting analysis. SCB = Santa Cruz Biotechnology (Santa Cruz, CA, USA). 2.7. Real-Time PCR 2.8. Immunohistofluorescence Paraffin-embedded sections (5 µm thick) were obtained following intravitreal admin- istration of 4% paraformaldehyde (PFA) in PBS; eyes were then post-fixed in 4% PFA for 24 h. The localization of PPAR isoforms (PPARγ and PPARα) in the retina and choroid was evaluated by immunohistofluorescence staining after deparaffination of the sections. A heat retrieval solution (Diva Decloaker, Biocare Medical, LLC, Pacheco, CA, USA) was used prior to incubation with specific primary antibodies (Table 3). Goat anti-mouse Alexa Fluor® 647 (Cat. No. CSA3808) or Goat anti-rabbit Alexa Fluor® 488 (Cat. No. CSA3211), where appropriate, were chosen as fluorescent secondary antibodies, and DAPI Fluoromount-G® was used as a nuclear/chromosomal counterstain. Table 3. Primary antibodies used for immunofluorescence studies. Table 3. Primary antibodies used for immunofluorescence studies. Primary Antibody Origin Dilution Reference Anti-PPARγ Mouse monoclonal 1:200 Santa Cruz Biotechnology, Santa Cruz, CA, USA Anti-PPARα Mouse monoclonal 1:200 Santa Cruz Biotechnology Anti-CD31 Rabbit monoclonal 1:200 Rockland Immunochemicals, Limerick, PA, USA 2.7. Real-Time PCR Total RNA from each retina sample was isolated with TRIzol® (Thermo Fisher Scientific, Madrid, Spain); then, reverse transcription reactions were carried out as described else- where [44]. Specific primers are listed in Table 2. Gene products were amplified in a CFX96 real-time PCR system (Bio-Rad, Madrid, Spain), and relative mRNA expression was quan- tified by the standard 2−∆∆Ct method, using glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as the housekeeping gene. Table 2. Primers used for real-time PCR. Gene Forward Primer (5′→3′) Reverse Primer (5′→3′) IL-6 CTCTGCAAGAGACTTCCATCC TTCTGCAAGTGCATCATCGT IL-1β CCGTGGACCTTCCAGGATGA GGGAAGGTCACACACCAGCA IL-10 CTGGACAACATACTGCTAACCG GGGCATCACTTCTACCAGGTAA TNF-α CCACGCTCTTCTGTCTACTG ACTTGGTGGTTTGCTACGAC GAPDH GCCAAAAGGGTCATCATCTCCGC GGATGACCTTGCCCACAGCCTTG 2 8 I hi t fl Table 2. Primers used for real-time PCR. 2.9. Statistical Analyses Results are expressed as means ± standard error of the mean (SEM). GraphPad InStat Software (v. 3.10, San Diego, CA, USA) was used to run one-way analysis of variance (ANOVA) followed by post-hoc Tukey’s multiple comparison test, and p < 0.05 was considered statistically different. Foods 2021, 10, 1993 6 of 18 3.1. Validation of the Experimental Approach At the end of the 6-week experimental period, SBP/DBP values showed a significant (p < 0.05) rise of both parameters in the L-NAME group (189/110 mmHg, respectively), in comparison with all other animal groups (Figure 1A). Dietary supplementation with ACE oil counteracted the typical effect of L-NAME, such that the values recorded in the LN + ACE group fell slightly below the hypertensive threshold (136/85 mmHg). On the other hand, the blood pressure lowering effect of EVOO was milder than that of ACE oil (161/97 mmHg for LN + EVOO group). As shown in Figure 1A, the intake of either oil had no effect in normotensive (L-NAME-free) mice (126/83 and 134/89 mmHg for ACE and EVOO groups, respectively) when compared with the Control group (123/80 mmHg). In addition, no differences were observed among any of the study groups in terms of weight gain (Figure 1B) or solid/liquid intake (Figure 1C). Figure 1. General parameters. (A) Final blood pressure, (B) weight gain and (C) liquid and solid diet intake in the six experimental animal groups. Values are expressed as mean ± SEM of seven animals per group: a p < 0.05 vs. Control; b p < 0.05 vs. L-NAME; d p < 0.05 vs. LN + EVOO; e p < 0.05 vs. ACE. 3.2. Retinal Function Analyzed by Full-Field ERG Figure 1. General parameters. (A) Final blood pressure, (B) weight gain and (C) liquid and solid diet intake in the six experimental animal groups. Values are expressed as mean ± SEM of seven animals per group: a p < 0.05 vs. Control; b p < 0.05 vs. L-NAME; d p < 0.05 vs. LN + EVOO; e p < 0.05 vs. ACE. 3 2 Retinal Function Analyzed by Full Field ERG 3. Results 3.1. Validation of the Experimental Approach 3.1. Validation of the Experimental Approach 3.3. PPARs Expression in Retina Layers 3.3. PPARs Expression in Retina Layers Peroxisome proliferator-activated receptor (PPAR) γ and PPARα expression and localization were quantified by Western blotting and by immunofluorescence. The hyper- tensive L-NAME group showed a significant (p < 0.05) decrease of both PPARγ (36%) and PPARα (42%) expression compared to the Control group (Figure 3A,B). Although normoten- sive animal groups fed ACE oil displayed upregulation of PPAR isoforms (1.6-fold), the LN + ACE group showed even higher overexpression of these receptors (2.4- and 2-fold for PPARγ and PPARα, respectively). PPARγ and PPARα were also upregulated in EVOO (1.5- and 1.3-fold, respectively) and in LN + EVOO (1.6- and 1.5-fold, respectively) groups relative to normotensive animals. However, when comparing the global effects of ACE oil and EVOO, a significantly (p < 0.05) greater capacity to upregulate PPARs was observed in the former. Quantification of immunofluorescence signal of PPARs in the retinal layers yielded similar results to those obtained from Western blotting analysis (Figure 3C,D). As shown in Figure 3E, PPARγ and PPARα expression was localized at the ganglion cell layer (GCL), inner plexiform layer (IPL), outer plexiform layer (OPL), outer segments (OS) and reti- nal pigment epithelium/choroid (RPE/CH). Fluorescence signals dropped drastically for both PPARγ (19%, 25%, 30%, 67% and 31% in RPE/CH, OS, OPL, IPL and GCL, re- spectively) and PPARα (47%, 72%, 91%, 79% and 72% in the same respective layers) in retinal sections obtained from L-NAME-treated animals, in comparison with the Control group. Oil-supplemented groups displayed a clearly visible increase in the retinal ex- pression of PPARs, with a more prominent effect in the case of ACE oil-fed hypertensive animals (PPARγ: 1.5-, 1.3-, 4.6-, 3.2- and 4.7-fold increase; PPARα: 2.5-, 1.3- 6.9-, 6.5- and 7.4-fold increase in RPE/CH, OS, OPL, IPL and GCL, respectively, in comparison to Con- trol group). In turn, upregulation of PPARs (relative to Control group) was only noted in some retinal layers in hypertensive mice fed EVOO (e.g., PPARγ expression increased 3.6-, 2.3- and 3.4-fold, and PPARα increased 5.3-, 6.5- and 2.44-fold, in OPL, IPL and GCL, respectively). Interestingly, PPARα immunofluorescence signal was generally higher than that of PPARγ in the different animal groups. In addition, PPARγ seems to yield higher signals in GCL and OPL, whereas PPARα signal was more abundant in IPL and OPL. Since the endothelial marker (anti-CD31) co-localized with PPAR immunofluorescence signals, these experiments confirmed the relevance of endothelial retinal cells in PPAR release. 3.2. Retinal Function Analyzed by Full-Field ERG Waveforms of the different recording conditions are depicted in Figure 2A–E. The analyses of these responses to light recorded after overnight dark-adaptation showed a significant (p < 0.05) reduction in amplitudes of scotopic waves b-scot (rods), a-mix and b-mix (mixed), and oscillatory potentials (OP), in the L-NAME group in comparison with Control animals (Figure 2F). Although no significant differences were observed in the b- phot amplitude, indicating no modifications in retinal activity of cones, and flickers (FL), a decreasing trend in its amplitude secondary to treatment with L-NAME could be extracted from our results. Regarding the groups fed with oil-enriched diets, no disturbances were found in LN + ACE and LN + EVOO animals, thus demonstrating the efficacy of both oil diets to prevent the negative effects of L-NAME on retinal function. In addition, no differences were found between any of the oil-supplemented groups (with or without the hypertensive phenotype), which means that no better efficacy is displayed between the ACE oil and EVOO diets in terms of visual retinal function. 7 of 18 Foods 2021, 10, 1993 ure 2. Electroretinogram (ERG) responses. Waveforms of representative ERG recordings: (A) b-scot (rods), (B) a- mix (mixed), (C) b-phot (cones), (D) oscillatory potentials (OP) and (E) flickers of each experimental group are represen Mean amplitude of all waves from the different experimental groups. Values are expressed as mean ± SEM of mals per group: a p < 0.05 vs. Control; c p < 0.05 vs. EVOO; d p < 0.05 vs. LN + EVOO; e p < 0.05 vs. ACE; f p < 0.0 + ACE. Figure 2. Electroretinogram (ERG) responses. Waveforms of representative ERG recordings: (A) b-scot (rods), (B) a-mix, b-mix (mixed), (C) b-phot (cones), (D) oscillatory potentials (OP) and (E) flickers of each experimental group are represented. (F) Mean amplitude of all waves from the different experimental groups. Values are expressed as mean ± SEM of ten animals per group: a p < 0.05 vs. Control; c p < 0.05 vs. EVOO; d p < 0.05 vs. LN + EVOO; e p < 0.05 vs. ACE; f p < 0.05 vs. LN + ACE. Foods 2021, 10, 1993 8 of 18 3.3. PPARs Expression in Retina Layers Figure 3. Cont. Figure 3. Cont. 9 of 18 Foods 2021, 10, 1993 Figure 3. Cont. Figure 3. Cont. Figure 3. Cont. 10 of 18 10 of 18 Foods 2021, 10, 1993 Figure 3. Protein expression of (A) PPARγ and (B) PPARα in retina homogenates. Quantitative analyses of fluorescence signal of (C) PPARγ and (D) PPARα in the retinal layers and choroid, and (E) representative fluorescence signal of PPARγ (left) and PPARα (right), as indicated. Panels show PPAR expression (red) and double staining with CD-31 (green) in the different retinal layers, with the merge visible in yellow color. Nuclei staining with DAPI (blue color) was used to identify the different retinal layers in each experimental group. Magnification: 10×. Values are expressed as mean ± SEM of five animals per group: a p < 0.05 vs. Control; b p < 0.05 vs. L-NAME; c p < 0.05 vs. EVOO; d p < 0.05 vs. LN + EVOO; e p < 0.05 vs. ACE. GCL: ganglion cell layer; IPL, inner plexiform layer; INL, inner nuclear layer; OPL, outer plexiform layer; ONL, outer nuclear layer; OS, outer segments; RPE/CH, retinal pigmentary epithelium/choroid. Figure 3. Protein expression of (A) PPARγ and (B) PPARα in retina homogenates. Quantitative analyses of fluorescence signal of (C) PPARγ and (D) PPARα in the retinal layers and choroid, and (E) representative fluorescence signal of PPARγ (left) and PPARα (right), as indicated. Panels show PPAR expression (red) and double staining with CD-31 (green) in the different retinal layers, with the merge visible in yellow color. Nuclei staining with DAPI (blue color) was used to identify the different retinal layers in each experimental group. Magnification: 10×. Values are expressed as mean ± SEM of five animals per group: a p < 0.05 vs. Control; b p < 0.05 vs. L-NAME; c p < 0.05 vs. EVOO; d p < 0.05 vs. LN + EVOO; e p < 0.05 vs. ACE. GCL: ganglion cell layer; IPL, inner plexiform layer; INL, inner nuclear layer; OPL, outer plexiform layer; ONL, outer nuclear layer; OS, outer segments; RPE/CH, retinal pigmentary epithelium/choroid. 3.4. Inflammatory Biomarkers in the Retina In retinal homogenates, L-NAME-treated mice presented with upregulation of pro- tein/gene expression of IL-6 (2.2- and 2.7-fold for protein and mRNA levels, respectively), IL-1β (1.8- and 2.1-fold, respectively), TNF-α (2.3- and 3.3-fold, respectively), and COX2 (2.6-fold), when compared to the Control group (Figure 4A–D,G–I). 4. Discussion The model of L-NAME-treated rodents has been widely used for in vivo induced experimental arterial hypertension (AH). SBP and DBP values obtained at the end of the treatment indicate the presence of severe hypertension in our study design, according to current guidelines on AH [45]. As previously reported, no significant (p > 0.05) effects on feeding behavior or weight gain were observed between normotensive and hypertensive mice after a 6-week period of feeding oil-enriched diets [19]. Our research group was pioneer in describing a blood pressure lowering effect of ACE oil in mice treated with L-NAME, showing a preferential action of this “wild origin” oil compared to a parallel EVOO-enriched diet. Our former analyses showed that ACE oil presented higher content in sterol, tocopherols, triterpene acids, alcohols, and secoiridoids than an EVOO of similar origin/characteristics. Therefore, the reduction of SBP and DBP could be partly mediated by these minor compounds with known antioxidant properties [46–49]. Specifically, the high content of secoiridoid compounds observed in ACE oil led us to think that these compounds might be responsible for the greater hypotensive effect observed in hypertensive animals fed this particular oil. The importance of AH as a risk factor for many pathologies, including neurological disorders [50] and regrettably widespread hypertensive retinopathy, warrants exploring how retinal function is affected in L-NAME-induced arterial hypertension. In that exper- imental group, our ERG recordings exhibited a remarkable reduction in amplitudes of b-scot (rod functionality), b-mix and a-mix waves, and a sightly reduction in OP, but no dif- ferences were attributable to AH in b-phot (cone activity) and FL waves. These findings are in agreement with previous assessment of visual function in spontaneously hypertensive rats (SHR), where b-scot amplitude was also reduced [51]. Our diminished OP amplitudes are also in line with Negretto et al. [52], who reported smaller OP in hypertensive patients, thus suggesting that the inner retina might be affected by AH. Previous morphometric analysis in the retina of L-NAME-treated animals showed thinner GCL, OS and RPE/CH layers [19,53], which might be associated with arterial sclerosis and vascular contraction in choroid [54], as well as with the reduction of retinal blood flow described in hypertensive patients [55]. 3.3. PPARs Expression in Retina Layers Despite no significant changes seen in IL-10 protein expression between Control and L-NAME groups, the gene expression was significantly lower (29% reduction; p < 0.05) in the latter (Figure 4E,F). Foods 2021, 10, 1993 11 of 18 Figure 4. Protein and gene expression of inflammation-related biomarkers IL-6 (A,B), IL-1β (C,D), IL-10 (E,F), TNF-α (G,H) and COX2 (I) in retina homogenates. Gene expression was quantified as relative to GAPDH in each corresponding group. Values are expressed as mean ± SEM of five animals per group: a p < 0.05 vs. Control; b p < 0.05 vs. L-NAME; c p < 0.05 vs. EVOO; d p < 0.05 vs. LN + EVOO; e p < 0.05 vs. ACE; f p < 0.05 vs. LN + ACE. Figure 4. Protein and gene expression of inflammation-related biomarkers IL-6 (A,B), IL-1β (C,D), IL-10 (E,F), TNF-α (G,H) and COX2 (I) in retina homogenates. Gene expression was quantified as relative to GAPDH in each corresponding group. Values are expressed as mean ± SEM of five animals per group: a p < 0.05 vs. Control; b p < 0.05 vs. L-NAME; c p < 0.05 vs. EVOO; d p < 0.05 vs. LN + EVOO; e p < 0.05 vs. ACE; f p < 0.05 vs. LN + ACE. Foods 2021, 10, 1993 12 of 18 Focusing on olive oil-enriched diets, ACE oil and EVOO-fed hypertensive animals benefited from reduced IL-6 gene and protein expression up to values similar or even lower than those found in control normotensive animals, which supports the competence of both oils to reduce the levels of this cytokine locally in the retina. Similar results were obtained regarding the expression of IL-1β (Figure 4C,D), and no differences were found between LN + ACE and LN + EVOO groups with respect to these two pro-inflammatory cytokines, except for IL-6 protein expression that was significantly lower in the former (Figure 4A). In contrast, ACE oil induced substantial upregulation of anti-inflammatory IL-10 in both L-NAME-free (2.5- and 2.7-fold for protein/mRNA expression, respectively) and L-NAME co-administered mice (2.9-/2.2-fold), an effect that was not observed either in EVOO or in LN + EVOO groups (Figure 4E,F). g g The similar expression of TNF-α found in Control, ACE, EVOO, LN + ACE and LN + EVOO groups was much lower than the values of the L-NAME group (Figure 4G,H). 3.3. PPARs Expression in Retina Layers Concerning COX2, the two oil diets downregulated its expression in hypertensive mice, but the reduction was greater in LN + ACE than in LN + EVOO group (200% vs. 111% relative to L-NAME, respectively). No significant changes were found in this regard between oil-free (Control) and oil-fed (ACE, EVOO) normotensive animals. 4. Discussion In this regard, PPARs have been shown to downregulate the expression of pro-inflammatory biomarkers in retinopathy microvascular dysfunction, as well as to regulate endothelial cell function by targeting angiogenesis [62,63]. In the current study, the clear reduction of PPARγ and PPARα expression found in the L-NAME group indicates that the retinal inflammatory profile could be affected in arterial hypertension via PPAR inhibition, an alteration that could be prevented with ACE oil and with EVOO-enriched diets (thus supporting a beneficial anti-inflammatory strategy via PPAR upregulation), with better performance in the case of ACE oil. In addition, the colocalized expression of both PPAR isoforms with CD-31 in GCL, IPL, OPL, OS retinal layer and in RPE/CH confirms the relationship between PPARs and endothelial cells. Preliminary studies carried out in our laboratory also confer beneficial effects to ACE oil in terms of improving endothelial dysfunction in aortas from L-NAME treated rats (unpublished data); interestingly, vascular reactivity in the aorta recovered in parallel with a reduction of endothelial inflammatory biomarkers, supporting the idea that ACE oil could also modulate retinal/choroidal endothelial cell function. Both olive oil and some of its minor components, such as polyphenols, have been described as useful regulators of PPAR expression [64,65], although regulation of PPAR expression in the hypertensive retina has not previously been reported in animal studies or in humans. In view of this interesting regulation on PPAR isoforms, and to further characterize the anti-inflammatory capacity of olive oils in the retina, we postulated that the profile of major inflammation-related biomarkers would be unbalanced in our experimental AH setting. Indeed, pro-inflammatory biomarkers (IL-6, IL-1β, TNF-α and COX2) were all abnormally elevated in hypertensive animals, a situation that was reversed after the simultaneous administration of oil-enriched diets. On the other hand, the protein and gene expression of anti-inflammatory IL-10 was highly upregulated by the oil diets, especially after ACE oil consumption. Interventions to reduce inflammation have been used in many retinopathies as a way to prevent and/or to treat retinal damage. Thus, some components of EVOO, such as omega-3 fatty acids, have been explored against retinopathy of prematurity (ROP) [66], as have polyphenols and flavonoids in DR [67]. In the current study, the slight differences found between ACE oil and EVOO in this regard might be ascribed to a different proportion of minor components. 4. Discussion Since b-scot wave and OP responses inform about inner retinal cell layers, mainly the activity of amacrine and bipolar cells, while a-wave reflects the activity of photoreceptors, specific modifications of the ERG-pattern in L-NAME-administered mice could be explained by the presence of retinal vascular dysfunction due to AH, which, in turn, would affect both the inner retina and OS layer. Moreover, since modifications of a-wave amplitude have been related to loss of photoreceptors [56], the reduction in the thickness of the OS and RPE/CH layers found in L-NAME-induced hypertensive animals Foods 2021, 10, 1993 13 of 18 suggests the existence of damaged photoreceptors with compromised retinal function in our animal model of AH. Interestingly, both ACE oil and EVOO diets were able to reverse the ERG alterations seen in the L-NAME group, reaching patterns like those found in the Control group. This supports the notion that diets containing ACE oil- and EVOO could be postulated as nutraceutical tools to counteract AH-related retinal dysfunction. p y As mentioned above, there is a great deal of evidence concerning the healthy properties of olive oil components based on the modulation of oxidative stress and inflammation; unfortunately, the literature about specific effects of EVOO on hypertensive retinas is very limited, and studies on the general properties and healthy potential of ACE oil are even scarcer. After evaluating the antioxidant properties of ACE oil in hypertensive retinas [19], we decided to analyze the possible anti-inflammatory properties derived from the daily consumption of this oily product. In this sense, we first focused on the role of nuclear receptors PPARs. PPARs are involved in the control of metabolic activities through differential regulation of glucose and lipid metabolism following activation by fatty acids [57], which makes them attractive targets for oil-mediated regulation. Moreover, PPARs can reduce excess inflammation by transcriptional regulation of a wide variety of genes, not only those related to inflammation but also those involved in metabolism, proliferation and differentiation pathways [58], and they can even regulate neurotoxic activities related to microglia activation [58]. PPAR expression and activation provides clear beneficial effects on different retinopathies of vascular origin [58]. These pleiotropic effects have prompted the use of different PPAR agonists to treat various inflammatory retinopathies, including DR, oxygen-induced retinopathy and AMD [59–61]. 4. Discussion As mentioned above, tocopherols, triterpene acids and polyphenols, mainly secoiridoids, are found in higher proportion in ACE oil, Foods 2021, 10, 1993 14 of 18 14 of 18 and these components have been attributed important anti-inflammatory properties. For instance, oleocanthal, one of the major secoiridoids found in ACE oil, has antioxidant and anti-inflammatory properties that could help reduce glial activation and inflammatory biomarkers [68,69]. Triterpene acids might also account for a preferential anti-inflammatory effect in ACE oil compared to EVOO. Oleanolic acid seem to have neuroprotective effects through modulation of inflammatory biomarkers (e.g., IL-6, IL-1β, TNF-α) and nitric oxide (NO) bioavailability [70,71]; and, together with ursolic acid, they were postulated as a promising anti-inflammatory compounds [42]. In the same way, maslinic acid reduced the inflammatory response through regulation of IL-1β [72] and COX-2 reduction, among other inflammatory biomarkers [73]. Moreover, not only did these compounds reduce pro-inflammatory biomarkers, but they also increased IL-10 levels [74–76]. In summary, ACE oil and EVOO exerted a retinoprotective effect in hypertensive mice based upon their anti-inflammatory properties, which adds value to their antioxidant effect recently demonstrated [19]. Our study offers a broad vision of how these extra-virgin olive oils can regulate inflammatory events in L-NAME-treated animals, counteracting the retinal dysfunction observed in ERG recordings in a hypertensive context. Although ACE oil tends to show better results than EVOO due to a higher content of some minor components, further experiments with specific molecules contained in olive oil are necessary to clarify these healthy effects on hypertensive retinas. 5. Conclusions The present work describes changes on retinal function and inflammatory events in the retina and choroid of a mouse model of L-NAME-induced hypertension. A greater anti-inflammatory effect seems to be attributable to ACE (wild olive) oil in hypertension- related ocular diseases in comparison with a reference EVOO of similar geographic origin and extraction method. A different profile between ACE oil and EVOO regarding minor components might explain the better outcomes in favor of the former. We postulate ACE oil- enriched diets as a novel nutraceutical tool to abolish AH-related retinal anti-inflammatory damage. Considering also its demonstrated antioxidant capacity, ACE oil could represent a promising therapeutical approach to prevent and/or to treat retinal pathologies, including hypertensive retinopathy, AMD, diabetic retinopathy and other vascular retinopathies. References Gorzynik-Debicka, M.; Przychodzen, P.; Cappello, F.; Kuban-Jankowska, A.; Gammazza, A.M.; Knap, N.; Wozniak, M.; Gorska- Ponikowska, M. Potential health benefits of olive oil and plant polyphenols. Int. J. Mol. Sci. 2018, 19, 686. [CrossRef] 11. Declerck, K.; Szarc vel Szic, K.; Palagani, A.; Heyninck, K.; Haegeman, G.; Morand, C.; Milenkovic, D.; Vanden Berghe, W. Epigenetic control of cardiovascular health by nutritional polyphenols involves multiple chromatin-modifying writer-reader- eraser proteins. Curr. Top. Med. Chem. 2015, 16, 788–806. [CrossRef] 12. Szyma´nska, R.; Nowicka, B.; Kruk, J. Vitamin E—Occurrence, Biosynthesis by Plants and Functions in Human Nutrition. Mini-Rev. Med. Chem. 2017, 17, 1039–1052. [CrossRef] 13. Pascual Fuster, V. Utilidad de los esteroles vegetales en el tratamiento de la hipercolesterolemia. Nutr. Hosp. 2017, 34, 62–67. [CrossRef] 14. Marcelino, G.; Hiane, P.A.; Freitas, K.d.C.; Santana, L.F.; Pott, A.; Donadon, J.R.; Guimarães, R.d.C.A. Effects of olive oil and its minor components on cardiovascular diseases, inflammation, and gut microbiota. Nutrients 2019, 11, 1826. [CrossRef] 15. Reboredo-Rodríguez, P.; Varela-López, A.; Forbes-Hernández, T.Y.; Gasparrini, M.; Afrin, S.; Cianciosi, D.; Zhang, J.; Manna, P.P.; Bompadre, S.; Quiles, J.L.; et al. Phenolic compounds isolated from olive oil as nutraceutical tools for the prevention and management of cancer and cardiovascular diseases. Int. J. Mol. Sci. 2018, 19, 2305. [CrossRef] g 16. Genovese, A.; Mondola, F.; Paduano, A.; Sacchi, R. Biophenolic compounds influence the in-mouth perceived intensity of virgin olive oil flavours and off-flavours. Molecules 2020, 25, 1969. [CrossRef] 16. Genovese, A.; Mondola, F.; Paduano, A.; Sacchi, R. Biophenolic compounds infl olive oil flavours and off-flavours. Molecules 2020, 25, 1969. [CrossRef] 17. Pedan, V.; Popp, M.; Rohn, S.; Nyfeler, M.; Bongartz, A. Characterization of phenolic compounds and their contribution to sensory properties of olive oil. Molecules 2019, 24, 2041. [CrossRef] roperties of olive oil. Molecules 2019, 24, 2041. [CrossR io Analítico Comparado Entre el Aceite de Acebuchina y el Aceite de Oliva Virgen. Ph.D. Thesis, Universidad pain, 2005. 18. Maqueda, J.E. Estudio Analítico Comparado Entre el Aceite de Acebuchina y el Aceite de Oliva Virgen. P de Sevilla, Sevilla, Spain, 2005. 19. Santana-Garrido, Á.; Reyes-Goya, C.; Pérez-Camino, M.C.; André, H.; Mate, A.; Vázquez, C.M.; Santana-garrido, Á.; Reyes-goya, C.; Carmen Pérez-Camino, M.; André, H.; et al. Retinoprotective effect of wild olive (Acebuche) oil- enriched diet against ocular oxidative stress induced by arterial hypertension. Antioxidants 2020, 9, 885. [CrossRef] y yp 20. Conflicts of Interest: The authors declare no conflict of interests. Conflicts of Interest: The authors declare no conflict of interests. References 1. Piroddi, M.; Albini, A.; Fabiani, R.; Giovannelli, L.; Luceri, C.; Natella, F.; Rosignoli, P.; Rossi, T.; Taticchi, A.; Servili, M.; et al. Nutrigenomics of extra-virgin olive oil: A review. BioFactors 2017, 43, 17–41. [CrossRef] [PubMed] g g 2. Martínez-González, M.A.; Gea, A.; Ruiz-Canela, M. The Mediterranean Diet and Cardiovascular Health: A Critical Review. Circ. Res. 2019, 124, 779–798. [CrossRef] [PubMed] 3. Guasch-Ferré, M.; Hu, F.B.; Martínez-González, M.A.; Fitó, M.; Bulló, M.; Estruch, R.; Ros, E.; Corella, D.; Recondo, J.; Gómez-Gracia, E.; et al. Olive oil intake and risk of cardiovascular disease and mortality in the PREDIMED Study. BMC Med. 2014, 12, 78. [CrossRef] [PubMed] [ ] [ ] 4. Lourida, I.; Soni, M.; Thompson-Coon, J.; Purandare, N.; Lang, I.A.; Ukoumunne, O.C.; Llewellyn, D.J. Mediterranean diet, cognitive function, and dementia: A systematic review. Epidemiology 2013, 24, 479–489. [CrossRef] 5. Di Daniele, N.D.; Noce, A.; Vidiri, M.F.; Moriconi, E.; Marrone, G.; Annicchiarico-Petruzzelli, M.; D’Urso, G.; Tesauro, M.; Rovella, V.; De Lorenzo, A.D. Impact of Mediterranean diet on metabolic syndrome, cancer and longevity. Oncotarget 2017, 8, 8947–8979. [CrossRef] 6. Foscolou, A.; Critselis, E.; Panagiotakos, D. Olive oil consumption and human health: A narrative review. Maturitas 2018, 118, 60–66. [CrossRef] Liu, X.; Luo, R.; Liao, G.; Li, L.; Liu, J.; Cheng, J.; Lu, Y.; Chen, Y. Oleic acid protects saturated fatty acid media Li, L.; Liu, X.; Luo, R.; Liao, G.; Li, L.; Liu, J.; Cheng, J.; Lu, Y.; Chen, Y. Oleic acid protects saturated fatty acid ty in hepatocytes and rat of non-alcoholic steatohepatitis. Life Sci. 2018, 203, 291–304. [CrossRef] 7. Chen, X.; Li, L.; Liu, X.; Luo, R.; Liao, G.; Li, L.; Liu, J.; Cheng, J.; Lu, Y.; Chen, Y. Oleic acid protects saturated fatty acid mediated lipotoxicity in hepatocytes and rat of non-alcoholic steatohepatitis. Life Sci. 2018, 203, 291–304. [CrossRef] p y p y p f 8. European Commission. Commission Regulation (EU) No 1018/2013 of 23 October 2013 amending Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods other than those referring to the reduction of disease risk and to children’s development and heal. Off. J. Eur. Union L 282 2013, 56, 43–45. Available online: http://eur-lex.europa.eu/pri/en/oj/ dat/2003/l_285/l_28520031101en00330037.pdf (accessed on 26 July 2021). p y 9. Angeloni, C.; Malaguti, M.; Barbalace, M.C.; Hrelia, S. Bioactivity of olive oil phenols in neuroprotection. Int. J. Mol. Sci. 2017, 18, 2230. [CrossRef] 10. 21. Merle, B.M.; Silver, R.E.; Rosner, B.; Seddon, J.M. Adherence to a Mediterranean diet, genetic susceptibility, and progression to advanced macular degeneration: A prospective cohort study. Am. J. Clin. Nutr. 2015, 102, 1196–1206. [CrossRef] 6. Patents The retinoprotective effect of acebuche oil was previously applied for patent by the authors (application number P202030625) on 23 June 2020, at the Oficina Española de Patentes y Marcas (OEPM), Ministerio de Industria, Comercio y Turismo. Author Contributions: Study design: A.M., C.M.V. and Á.S.-G.; data management: A.M., Á.S.-G. and C.M.V.; data acquisition: Á.S.-G. and S.M.-N.; draft of the article: Á.S.-G.; revision of the article: Á.S.-G., C.R.-G., H.A., S.M.-N., P.d.l.V., A.M. and C.M.V. All authors have read and agreed to the published version of the manuscript. Funding: This research and the APC were funded by Agencia Estatal de Investigación, Ministerio de Ciencia e Innovación, Gobierno de España (PID2019-109002RB-I00/AEI/10.13039/501100011033); Consejería de Economía, Conocimiento, Empresas y Universidad, Junta de Andalucía (2020/275 and 2021/188; CTS-584); and VI PPIT Universidad de Sevilla (IV.7 Ayuda Suplementaria a Grupos de Investigación por captación de fondos en las convocatorias de proyectos de investigación del Plan Estatal, 2020/1163). AS is recipient of an FPU predoctoral fellowship from Ministerio de Universidades (FPU17/03465). CR-G was supported by Ministerio de Ciencia e Innovación, Ayudas para la Promoción de Empleo Joven e Implantación de la Garantía Juvenil en I + D+i 2017–2020 (PEJ2018-004474-A). Institutional Review Board Statement: The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the relevant Institutional Animal Care and Use Com- mittee: Dirección General de Producción Agrícola y Ganadería, Junta de Andalucía (protocol code 13/03/2019/031, date of approval 20 March 2019). 15 of 18 Foods 2021, 10, 1993 15 of 18 ta Availability Statement: The data presented in this study are available in the article. Acknowledgments: We are thankful for the technical support from Centro de Innovación, Tecnología e Innovación de la Universidad de Sevilla (CITIUS, Servicio de Biología, Servicio de Microscopía). The authors are also grateful to Alcazarín Reunidos FP, S.L. (Monda, Málaga, Spain) for providing the extra virgin olive (wild/cultivated) oils used in this study. Acknowledgments: We are thankful for the technical support from Centro de Innovación, Tecnología e Innovación de la Universidad de Sevilla (CITIUS, Servicio de Biología, Servicio de Microscopía). The authors are also grateful to Alcazarín Reunidos FP, S.L. (Monda, Málaga, Spain) for providing the extra virgin olive (wild/cultivated) oils used in this study. References Guzik, T.J.; Touyz, R.M. Oxidative stress, inflammation, and vascular aging in hypertension. Hypertension 2017, 70, 660–667. [CrossRef] [ ] 30. Mehaffey, E.; Majid, D.S.A. Tumor necrosis factor-α, kidney function, and hypertension. Am. J. Physiol.-Ren. Physiol. 2017, 313, F1005–F1008. [CrossRef] 31. Pinheiro Júnior, J.E.G.; Moraes, P.Z.; Rodriguez, M.D.; Simões, M.R.; Cibin, F.; Pinton, S.; Barbosa Junior, F.; Peçanha, F.M.; Vassallo, D.V.; Miguel, M.; et al. Cadmium exposure activates NADPH oxidase, renin–angiotensin system and cyclooxygenase 2 pathways in arteries, inducing hypertension and vascular damage. Toxicol. Lett. 2020, 333, 80–89. [CrossRef] 32. Tanase, D.M.; Gosav, E.M.; Radu, S.; Ouatu, A.; Rezus, C.; Ciocoiu, M.; Costea, C.F.; Floria, M. Arterial Hypertension and Interleukins: Potential Therapeutic Target or Future Diagnostic Marker? Int. J. Hypertens. 2019, 2019, 3159283. [CrossRef] [PubMed] [ ] 33. McMaster, W.G.; Kirabo, A.; Madhur, M.S.; Harrison, D.G. Inflammation, Immunity, and Hypertensive End-Organ Damage. Circ. Res. 2015, 116, 1022–1033. [CrossRef] 34. Formanowicz, D.; Rybarczyk, A.; Radom, M.; Formanowicz, P. A role of inflammation and immunity in essential hypertension— modeled and analyzed using Petri nets. Int. J. Mol. Sci. 2020, 21, 3348. [CrossRef] [PubMed] y g 35. Wang, W.; Lo, A.C.Y. Diabetic retinopathy: Pathophysiology and treatments. Int. J. Mol. Sci. 2018, 19 ; Lo, A.C.Y. Diabetic retinopathy: Pathophysiology and treatments. Int. J. Mol. Sci. 2018, 19, 1816. [CrossRef] 35. Wang, W.; Lo, A.C.Y. Diabetic retinopathy: Pathophysiology and treatments. Int. J. Mol. Sci. 2018, 19, 1816. [CrossRef] [PubMed] 36. Baudouin, C.; Kolko, M.; Melik-Parsadaniantz, S.; Messmer, E.M. Inflammation in Glaucoma: From the back to the front of the eye, and beyond. Prog. Retin. Eye Res. 2020, 100916. [CrossRef] g p y p y gy 36. Baudouin, C.; Kolko, M.; Melik-Parsadaniantz, S.; Messmer, E.M. Inflammation in Glaucoma: From the back to the front of the eye, and beyond. Prog. Retin. Eye Res. 2020, 100916. [CrossRef] y y g y 37. Kauppinen, A.; Paterno, J.J.; Blasiak, J.; Salminen, A.; Kaarniranta, K. Inflammation and its role in age-related macular degenera- tion. Cell. Mol. Life Sci. 2016, 73, 1765–1786. [CrossRef] [PubMed] 38. Coban, E.; Nizam, I.; Topal, C.; Akar, Y. The Association of Low-Grade Systemic Inflammation with Hypertensive Retinopathy. Clin. Exp. Hypertens. 2011, 32, 528–531. [CrossRef] 39. Silva, K.C.; Pinto, C.C.; Biswas, S.K.; De Faria, J.B.L.; De Faria, J.M.L. Hypertension increases retinal inflammation in experimental diabetes: A possible mechanism for aggravation of diabetic retinopathy by hypertension. Curr. Eye Res. 2007, 32, 533–541. [CrossRef] [ ] 40. References Carnés Sánchez, J.; Iraola, V.M.; Sastre, J.; Florido, F.; Boluda, E.; Fernández-Caldas, L.; Carnes Sanchez, J.; Iraola, V.M.; Sastre, J.; Florido, F.; et al. Allergenicity and immunochemical characterization of six varieties of Olea europaea. Allergy Eur. J. Allergy Clin. Immunol. 2002, 57, 313–318. [CrossRef] 21. Merle, B.M.; Silver, R.E.; Rosner, B.; Seddon, J.M. Adherence to a Mediterranean diet, genetic susceptibility, and progression to advanced macular degeneration: A prospective cohort study. Am. J. Clin. Nutr. 2015, 102, 1196–1206. [CrossRef] Foods 2021, 10, 1993 16 of 18 16 of 18 22. Merle, B.M.J.; Silver, R.E.; Rosner, B.; Seddon, J.M.; Mares, J.A.; Voland, R.P.; Sondel, S.A.; Millen, A.E.; LaRowe, T.; Moeller, S.M.; et al. Healthy lifestyles related to subsequent prevalence of age-related macular degeneration. Arch. Ophthalmol. 2011, 129, 470–480. [CrossRef] 24. Zhu, L.; Liu, Z.; Feng, Z.; Hao, J.; Shen, W.; Li, X.; Sun, L.; Sharman, E.; Wang, Y.; Wertz, K.; et al. Hydroxytyrosol protects against oxidative damage by simultaneous activation of mitochondrial biogenesis and phase II detoxifying enzyme systems in retinal pigment epithelial cells. J. Nutr. Biochem. 2010, 21, 1089–1098. [CrossRef] 25. Zou, X.; Feng, Z.; Li, Y.; Wang, Y.; Wertz, K.; Weber, P.; Fu, Y.; Liu, J. Stimulation of GSH synthesis to prevent oxidative stress-induced apoptosis by hydroxytyrosol in human retinal pigment epithelial cells: Activation of Nrf2 and JNK-p62/SQSTM1 pathways. J. Nutr. Biochem. 2012, 23, 994–1006. [CrossRef] p y 26. González-Correa, J.A.; Rodríguez-Pérez, M.D.; Márquez-Estrada, L.; López-Villodres, J.A.; Reyes, J.J.; Rodriguez-Gutierrez, G.; Fernández-Bolaños, J.; De La Cruz, J.P. Neuroprotective Effect of Hydroxytyrosol in Experimental Diabetic Retinopathy: Relation- ship with Cardiovascular Biomarkers. J. Agric. Food Chem. 2018, 66, 637–644. [CrossRef] 27. Benlarbi, M.; Jemai, H.; Hajri, K.; Mbarek, S.; Amri, E.; Jebbari, M.; Hammoun, I.; Baccouche, B.; Boudhrioua Mihoubi, N.; Zemmal, A.; et al. Neuroprotective effects of oleuropein on retina photoreceptors cells primary culture and olive leaf extract and oleuropein inhibitory effects on aldose reductase in a diabetic model: Meriones shawi. Arch. Physiol. Biochem. 2020, 1–8. [CrossRef] 28. Agita, A.; Thaha, M.; Agita, A.; Alsagaff, M.T. Inflammation, Immunity, and Hypertension. Acta Med. Indones. 2017, 49, 158–165. 29. Guzik, T.J.; Touyz, R.M. Oxidative stress, inflammation, and vascular aging in hypertension. Hypertension 2017, 70, 660–667. [CrossRef] 28. Agita, A.; Thaha, M.; Agita, A.; Alsagaff, M.T. Inflammation, Immunity, and Hypertension. Acta M 29 G ik T J T R M O id i i fl i d l i i h i H 29. References Robles-Almazan, M.; Pulido-Moran, M.; Moreno-Fernandez, J.; Ramirez-Tortosa, C.; Rodriguez-Garcia, C.; Quiles, J.L.; Ramirez- Tortosa, M. Hydroxytyrosol: Bioavailability, toxicity, and clinical applications. Food Res. Int. 2018, 105, 654–667. [CrossRef] zan, M.; Pulido-Moran, M.; Moreno-Fernandez, J.; Ramirez-Tortosa, C.; Rodriguez-Garcia, C.; Quiles, J.L.; R s-Almazan, M.; Pulido-Moran, M.; Moreno-Fernandez, J.; Ramirez-Tortosa, C.; Rodriguez-Garcia, C.; Quiles M H d t l Bi il bilit t i it d li i l li ti F d R I t 2018 105 654 667 [C s Almazan, M.; Pulido Moran, M.; Moreno Fernandez, J.; Ramirez Tortosa, C.; Rodriguez Garcia, C.; Quiles sa, M. Hydroxytyrosol: Bioavailability, toxicity, and clinical applications. Food Res. Int. 2018, 105, 654–667. [C 41. Francisco, V.; Ruiz-Fernández, C.; Lahera, V.; Lago, F.; Pino, J.; Skaltsounis, L.; González-Gay, M.A.; Mobasheri, A.; Gómez, R.; Scotece, M.; et al. Natural Molecules for Healthy Lifestyles: Oleocanthal from Extra Virgin Olive Oil. J. Agric. Food Chem. 2019, 67, 3845–3853. [CrossRef] 42. Kashyap, D.; Sharma, A.; Tuli, H.S.; Punia, S.; Sharma, A.K. Ursolic Acid and Oleanolic Acid: Pentacyclic Terpenoids with Promising Anti-Inflammatory Activities. Recent Pat. Inflamm. Allergy Drug Discov. 2016, 10, 21–33. [CrossRef] 43. Bradford, M.M. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal. Biochem. 1976, 72, 248–254. [CrossRef] 44. Santana-Garrido, Á.; Reyes-Goya, C.; André, H.; Aramburu, Ó.; Mate, A.; Vázquez, C.M. Sunitinib-induced oxidative imbalance and retinotoxic effects in rats. Life Sci. 2020, 257, 118072. [CrossRef] 45. Whelton, P.K.; Carey, R.M.; Aronow, W.S.; Casey, D.E.; Collins, K.J.; Himmelfarb, C.D.; DePalma, S.M.; Gidding, S.; Jamerson, K.A.; Jones, D.W.; et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Hypertension 2018, 71, e13–e115. [CrossRef] 17 of 18 17 of 18 Foods 2021, 10, 1993 46. He, W.-S.; Zhu, H.; Chen, Z.-Y. Plant Sterols: Chemical and Enzymatic Structural Modifications and Effects on Their Cholesterol- Lowering Activity. J. Agric. Food Chem. 2018, 66, 3047–3062. [CrossRef] g M.; Fitó, M. Olive oil phenolic compounds and high-density lipoprotein function. Curr. Opin. Lipidol. 2016 ] 47. Hernáez, A.; Farràs, M.; Fitó, M. Olive oil phenolic compounds and high-density lipoprotein function. Curr. Opin. Lipidol. 2016, 27, 47–53. [CrossRef] 48. Zarrouk, A.; Martine, L.; Grégoire, S.; Nury, T.; Meddeb, W.; Camus, E.; Badreddine, A.; Durand, P.; Namsi, A.; Yammine, A.; et al. References Profile of Fatty Acids, Tocopherols, Phytosterols and Polyphenols in Mediterranean Oils (Argan Oils, Olive Oils, Milk Thistle Seed Oils and Nigella Seed Oil) and Evaluation of their Antioxidant and Cytoprotective Activities. Curr. Pharm. Des. 2019, 25, 1791–1805. [CrossRef] cer, J.P.E.; Rowland, I.R.; Commane, D.M. Olive Polyphenols and the Metabolic Syndrome. Molecules 2017, 22 49. Saibandith, B.; Spencer, J.P.E.; Rowland, I.R.; Commane, D.M. Olive Polyphenols and the Metabolic Syndrome. Molecules 2017, 22, 1082. [CrossRef] ell, P.M. Blood pressure and the brain: The neurology of hypertension. Pract. Neurol. 2020, 20, 100–111 50. Kelly, D.M.; Rothwell, P.M. Blood pressure and the brain: The neurology of hypertension. Prac [CrossRef] 51. Sicard, P.; Acar, N.; Grégoire, S.; Lauzier, B.; Bron, A.M.; Creuzot-Garcher, C.; Bretillon, L.; Vergely, C.; Rochette, L. Influence of rosuvastatin on the NAD(P)H oxidase activity in the retina and electroretinographic response of spontaneously hypertensive rats. Br. J. Pharmacol. 2007, 151, 979–986. [CrossRef] 52. Negretto, A.D.; Rosa, A.A.M.; Nakashima, A.A.; Ortega, K.C.; Mion Júnior, D.; Oyamada, M.K.; Nakashima, Y. Avaliação da retinopatia hipertensiva através do potencial oscilatório do eletrorretinograma. Arq. Bras. Oftalmol. 2008, 71, 38–42. [CrossRef] [PubMed] 53. Santana-garrido, Á.; Reyes-goya, C.; Fernández-bobadilla, C.; Blanca, A.J.; Mate, A.; Vázquez, C.M. NADPH oxidase—Induced oxidative stress in the eyes of hypertensive rats. Mol. Vis. 2021, 28, 161–178. 54. Akay, F.; Gundogan, F.C.; Yolcu, U.; Toyran, S.; Uzun, S. Choroidal thickness in systemic arterial hyp 2015, 26, 152–157. [CrossRef] 55. Lim, H.B.; Lee, M.W.; Park, J.H.; Kim, K.; Jo, Y.J.; Kim, J.Y. Changes in Ganglion Cell–Inner Plexiform Layer Thickness and Retinal Microvasculature in Hypertension: An Optical Coherence Tomography Angiography Study. Am. J. Ophthalmol. 2019, 199, 167–176. [CrossRef] 56. Machida, S.; Kondo, M.; Jamison, J.A.; Khan, N.W.; Kononen, L.T.; Sugawara, T.; Bush, R.A.; Si transgenic rat: Correlation of retinal function with histopathology. Investig. Ophthalmol. Vis. Sci. 20 56. Machida, S.; Kondo, M.; Jamison, J.A.; Khan, N.W.; Kononen, L.T.; Sugawara, T.; Bush, R.A.; Sieving, P.A. P23H rhodopsin transgenic rat: Correlation of retinal function with histopathology. Investig. Ophthalmol. Vis. Sci. 2000, 41, 3200–3209. g p gy g p 57. Hernandez-Quiles, M.; Broekema, M.F.; Kalkhoven, E. PPARgamma in Metabolism, Immunity, and Mechanisms of Action. Front. Endocrinol. 2021, 12, 624112. [CrossRef] M.; Broekema, M.F.; Kalkhoven, E. PPARgamma in Metabolism, Immunity, and Cancer: Unified and Diverse on. Front. Endocrinol. 2021, 12, 624112. [CrossRef] 58. References Doroshenko, E.R.; Drohomyrecky, P.C.; Gower, A.; Whetstone, H.; Cahill, L.S.; Ganguly, M.; Spring, S.; Yi, T.J.; Sled, J.G.; Dunn, S.E. Peroxisome Proliferator-Activated Receptor-δ Deficiency in Microglia Results in Exacerbated Axonal Injury and Tissue Loss in Experimental Autoimmune Encephalomyelitis. Front. Immunol. 2021, 12, 371. [CrossRef] ; Weber, G.M.; Folkman, J.; Aiello, L.P. Rosiglitazone and delayed onset of proliferative diabetic retinopathy 08, 126, 793–799. [CrossRef] 59. Shen, L.Q.; Child, A.; Weber, G.M.; Folkman, J.; Aiello, L.P. Rosiglitazone and delayed onset of prolifera Arch. Ophthalmol. 2008, 126, 793–799. [CrossRef] 60. Ye, S.; Chen, Q.; Jiang, N.; Liang, X.; Li, J.; Zong, R.; Huang, C.; Qiu, Y.; Ma, J.X.; Liu, Z. PPARα-dependent effects of palmitoylethanolamide against retinal neovascularization and fibrosis. Investig. Ophthalmol. Vis. Sci. 2020, 61, 15. [CrossRef] p y g 61. Joharapurkar, A.; Patel, V.; Kshirsagar, S.; Patel, M.S.; Savsani, H.; Jain, M. Effect of dual PPAR-α/γ agonist saroglitazar on diabetic retinopathy and oxygen-induced retinopathy. Eur. J. Pharmacol. 2021, 899, 174032. [CrossRef] [PubMed] 62. Hu, Y.; Chen, Y.; Ding, L.; He, X.; Takahashi, Y.; Gao, Y.; Shen, W.; Cheng, R.; Chen, Q.; Qi, X.; et al. Pathogenic role of diabetes-induced PPAR-α down-regulation in microvascular dysfunction. Proc. Natl. Acad. Sci. USA 2013, 110, 15401–15406. [CrossRef] [PubMed] 63. Kotlinowski, J.; Jozkowicz, A. PPAR Gamma and Angiogenesis: Endothelial Cells Perspective. J. Diabetes Res. 2016, 2016, 8492353. [CrossRef] [PubMed] 64. Farràs, M.; Valls, R.M.; Fernández-Castillejo, S.; Giralt, M.; Solà, R.; Subirana, I.; Motilva, M.J.; Konstantinidou, V.; Covas, M.I.; Fitó, M. Olive oil polyphenols enhance the expression of cholesterol efflux related genes in vivo in humans. A randomized controlled trial. J. Nutr. Biochem. 2013, 24, 1334–1339. [CrossRef] [PubMed] 65. Medeiros-De-Moraes, I.M.; Gonçalves-De-Albuquerque, C.F.; Kurz, A.R.M.; De Jesus Oliveira, F.M.; Pereira de Abreu, V.H.; Torres, R.C.; Carvalho, V.F.; Estato, V.; Bozza, P.T.; Sperandio, M.; et al. Omega-9 oleic acid, the main compound of olive oil, mitigates inflammation during experimental sepsis. Oxid. Med. Cell. Longev. 2018, 2018, 6053492. [CrossRef] 66. Connor, K.M.; SanGiovanni, J.P.; Lofqvist, C.; Aderman, C.M.; Chen, J.; Higuchi, A.; Hong, S.; Pravda, E D.; et al. Omega-3 Reduces Pathological Retinal Angiogenesis. Nat. Med. 2007, 13, 868–873. [CrossRef] q g g ; et al. Omega-3 Reduces Pathological Retinal Angiogenesis. Nat. Med. 2007, 13, 868–873. [CrossRef] 67. Rossino, M.G.; Casini, G. Nutraceuticals for the treatment of diabetic retinopathy. References Nutrients 2019, 11, 7 68 Pang K L ; Chin K Y The biological activities of oleocanthal from a molecular perspective Nutrients 2 67. Rossino, M.G.; Casini, G. Nutraceuticals for the treatment of diabetic retinopathy. Nutrients 2019, 11, 771. [Cros 68. Pang, K.L.; Chin, K.Y. The biological activities of oleocanthal from a molecular perspective. Nutrients 2018, 10, 570. [CrossRef] 69. Scotece, M.; Conde, J.; Abella, V.; López, V.; Francisco, V.; Ruiz, C.; Campos, V.; Lago, F.; Gomez, R.; Pino, J.; et al. Oleocanthal Inhibits Catabolic and Inflammatory Mediators in LPS-Activated Human Primary Osteoarthritis (OA) Chondrocytes Through g, ; , g p p , , [ ] 69. Scotece, M.; Conde, J.; Abella, V.; López, V.; Francisco, V.; Ruiz, C.; Campos, V.; Lago, F.; Gomez, R.; Pino, J.; et al. Oleocanthal Inhibits Catabolic and Inflammatory Mediators in LPS-Activated Human Primary Osteoarthritis (OA) Chondrocytes Through MAPKs/NF-κB Pathways. Cell. Physiol. Biochem. 2018, 49, 2414–2426. [CrossRef] y 70. Bao, J.; Yan, W.; Xu, K.; Chen, M.; Chen, Z.; Ran, J.; Xiong, Y.; Wu, L. Oleanolic Acid Decreases IL-1 β -Induced Activation of Fibroblast-Like Synoviocytes via the SIRT3-NF- κ B Axis in Osteoarthritis. Oxid. Med. Cell. Longev. 2020, 2020, 7517219. [CrossRef] 18 of 18 Foods 2021, 10, 1993 18 of 18 71. Castellano, J.M.; Garcia-Rodriguez, S.; Espinosa, J.M.; Millan-Linares, M.C.; Rada, M.; Perona, J.S. Oleanolic acid exerts a neuroprotective effect against microglial cell activation by modulating cytokine release and antioxidant defense systems. Biomolecules 2019, 9, 683. [CrossRef] 72. Chen, Y.L.; Yan, D.Y.; Wu, C.Y.; Xuan, J.W.; Jin, C.Q.; Hu, X.L.; Bao, G.D.; Bian, Y.J.; Hu, Z.C.; Shen, Z.H.; et al. Maslinic acid prevents IL-1β-induced inflammatory response in osteoarthritis via PI3K/AKT/NF-κB pathways. J. Cell. Physiol. 2021, 236, 1939–1949. [CrossRef] 73. Lee, W.; Kim, J.; Park, E.K.; Bae, J.S. Maslinic acid ameliorates inflammation via the downregulation of NF-κB and STAT-1. Antioxidants 2020, 9, 106. [CrossRef] 74. Da Silva Ferreira, D.; Esperandim, V.R.; Toldo, M.P.A.; Kuehn, C.C.; Do Prado Júnior, J.C.; Cunha, W.R.; Silva, M.L.A.e.; Albuquerque, S.d. In vivo activity of ursolic and oleanolic acids during the acute phase of Trypanosoma cruzi infection. Exp. Parasitol. 2013, 134, 455–459. [CrossRef] 75. Giner, E.; Recio, M.C.; Ríos, J.L.; Giner, R.M. Oleuropein protects against dextran sodium sulfate-induced chronic colitis in mice. J. Nat. Prod. 2013, 76, 1113–1120. [CrossRef] 76. Patti, A.M.; Carruba, G.; Cicero, A.F.G.; Banach, M.; Nikolic, D.; Giglio, R.V.; Terranova, A.; Soresi, M.; Giannitrapani, L.; Montalto, G.; et al. 71. Castellano, J.M.; Garcia-Rodriguez, S.; Espinosa, J.M.; Millan-Linares, M.C.; Rada, M.; Perona, J.S. Oleanolic acid exerts a neuroprotective effect against microglial cell activation by modulating cytokine release and antioxidant defense systems. Biomolecules 2019, 9, 683. [CrossRef] References Daily use of extra virgin olive oil with high oleocanthal concentration reduced body weight, waist circumference, alanine transaminase, inflammatory cytokines and hepatic steatosis in subjects with the metabolic syndrome: A 2-month intervention study. Metabolites 2020, 10, 392. [CrossRef]
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Comfort experience in palliative care: a phenomenological study
BMC palliative care
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6,491
© 2016 The Author(s). Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Coelho et al. BMC Palliative Care (2016) 15:71 DOI 10.1186/s12904-016-0145-0 Coelho et al. BMC Palliative Care (2016) 15:71 DOI 10.1186/s12904-016-0145-0 Abstract Background: Palliative care aims to provide maximum comfort to the patient. However it is unknown what factors facilitate or hinder the experience of comfort, from the perspective of inpatients of palliative care units. This lack of knowledge hinders the development of comfort interventions adjusted to these patients. The aim of this research is to describe the comfort and discomfort experienced by inpatients at palliative care units. Methods: A phenomenological descriptive study was undertaken. Ten inpatients were recruited from a Spanish palliative care unit and seven from a Portuguese palliative care unit. Data were collected using individual interviews and analysed following the method of Giorgi. Results: Four themes reflect the essence of the lived experience: The Palliative Care as a response to the patient’s needs with advanced disease, attempt to naturalize advanced disease, confrontation with their own vulnerability, openness to the spiritual dimension. Conclusions: Informants revealed that they experience comfort through humanized care, differentiated environment, symptomatic control, hope and relationships. The discomfort emerges from the losses and powerlessness against their situation. Even if such findings may seem intuitive, documenting them is essential because it invites us to reflect on our convictions about what it means to be comfortable for these patients, and allows incorporating this information in the design of focused interventions to maximize the comfort experience. Keywords: Palliative care, End of life care, Inpatients, Qualitative research, Phenomenology, Comfor Comfort experience in palliative care: a phenomenological study Adriana Coelho1* , Vitor Parola1, Miguel Escobar-Bravo2 and João Apóstolo3 prehension of the phenomenon. However, in the cont of Palliative Care (PC), such investigations are scarce [ * Correspondence: adriananevescoelho@esenfc.pt 1Nursing School of Coimbra, Coimbra, Portugal Full list of author information is available at the end of the article © 2016 The Author(s). Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Background beyond physical symptoms management [5]. Nevertheless the literature continues to give more attention to the physical comfort [6–8], and little attention is given to other aspects of comfort commonly observed among these patients [9]. The development of science and technology is expressed in an increase in life expectancy [1]. Therefore the popu- lation’s aging in a society in which death may be delayed ever more, allows us to predict a gradual increase in the prevalence of degenerative and disabling diseases. Also in recent years the process of dying was displaced from the home environment for the hospital context [2]. Indeed, Kolcaba [10], defines comfort as the immediate experience of being strengthened by having the needs for three types of comfort (relief, ease, or renewal) met in four contexts of human experience (physical, psychospiritual, environmental, and social). In this sense, there has been an increment of palliative care units (PCUs) with the aim of provide the greatest comfort and dignity possible to patients and their families facing the problem associated with life-threatening illness [1, 3]. In this sense, knowing the experiences of comfort and discomfort of patients are a relevant aspect for the prac- tice of care, guiding the care provided for the patients’ needs and maximizing the effect of comfort interventions. However, patients with advanced disease still experi- ence discomfort [4]. This could be explained by the fact that these patients often have comfort needs that extend Some researchers have sought to understand the com- fort experience in the view of patients in other contexts [11–14]. These studies are important efforts to the com- prehension of the phenomenon. However, in the context of Palliative Care (PC), such investigations are scarce [8]. * Correspondence: adriananevescoelho@esenfc.pt 1Nursing School of Coimbra, Coimbra, Portugal Full list of author information is available at the end of the article Coelho et al. BMC Palliative Care (2016) 15:71 Coelho et al. BMC Palliative Care (2016) 15:71 Page 2 of 8 Table 1 Inclusion and exclusion criteria Inclusion criteria Exclusion criteria - Adult patients with incurable and advanced disease; - Patients with cognitive alterations; - Able to consent; - Dying patients. - Able to speak Spanish or Portuguese; - In health conditions that allow them to tolerate an interview of at least 20 min; - Stay period in the PCU equal or superior to 3 days. Background Table 1 Inclusion and exclusion criteria There are only studies that describe this experience, in some of the contexts of comfort, but from the professional [15–18], or families perspective [19, 20]. However, it is important to note that both family and health profes- sionals tend to describe the physical [21–24], and emo- tional symptoms [21, 25–27], differently to the patient. Therefore it is not clarified what is the patient comfort experience, and known that the patient’s comfort is an important objective of PC, their comfort experience should be taken into account. Furthermore, the analysis of the literature evidence that the comfort interventions in PC are intuitive or based on medical principles [28]. of being hospitalized in this unit?, with the intention of the significant experience of comfort and discomfort to emerge freely. Therefore being comfort/discomfort subjective states that can only be understood in the light of the patient’s experiences, starting from a concrete reality [29], and with the conviction that intervention processes must take into account the complexity and subjectivity of the patient experience, it was conducted this study in order to describe the comfort and discomfort experienced by inpatients at PCUs. Follow-up questions in order to deepen understanding of the experience of the informants were also carried, such as: How would you describe this in more detail? What does that mean to you? A pilot test with two patients was conducted in order to adjust the interview question. These interviews were not included. Study design The present study is a secondary aim of a larger project about confort interventions. This study was conducted using a qualitative phenom- enological descriptive design. A descriptive phenomenology was chosen, in order to study the complex phenomenon of human experience, giving emphasis to how the life-world is described by the participants voices [30]. It was assumed that saturation had been reached after the 10 Spanish PCU and 7 Portuguese PCU interview. Non-participants refused to participate in the study or dropped out during the interview. Data collection was carried exclusively by one of the in- vestigators (AC) in order to avoid significant differences in conduction the interview. Transcripts were reviewed by the interviewer (AC) to verify their accuracy. This study conforms to Consolidated Criteria for Reporting Qualitative Research (COREQ) guidelines (see Additional file 1). The findings were not returned to participants for confirmation because of participants’ declining health. Participants and setting Study participants were recruited from a Portuguese and Spanish PCUs, between March and May 2015. Table 2 Participants Spanish PCU Portuguese PCU Total Gender Male 5 3 8 Female 5 4 9 Age Range: 58–90 years Range: 56–78 years Mean: 70.5 Mean: 74 years Mean: 67 years Hospitalization time Range: 4–44 days Range: 9–76 days Mean: 22.5 Mean: 14 days Mean: 31 days Diagnoses Oncologic 7 7 14 Non-oncologic 3 0 3 The heads nurses, invited face-to-face those who were eligible to participate (Table 1). A purposive sampling strategy was performed to ensure a sample that included a wide spectrum of participant gender, ages, hospitalization time, and diagnoses [31]. A total of 17 inpatients participated (Table 2). Methods Study design Interviews were individual, mean duration was 32 min, and were held in a location of the participants’ choice (their room or an intimate space in the PCU). They were digitally audio-recorded and transcribed verbatim. The PC as a response to patient’s needs with advanced disease Informants acknowledge that, to find responses to their health care needs, they need to be hospitalized in a PCU: In third step the delineated meaning units identified in the previous step were transformed in appropriate lan- guage to the phenomenon under study and grouped into common themes and sub-themes that represent the es- sence of comfort experiences. In this step, the researchers performed imaginative variation by changing qualities of the object under analyzed so as to determine which data are essential. The imaginative variation permitted to deter- mine the essence of the phenomenal structure of the experience. P16 “(…) the pain and the shortness of breath, that is the thing I was not able to control, and that was creating some fearful respect. At the hospital I am well, arriving home, I stay there for a little longer and that’s it…loss of control.” The PCU is perceived as a relief space of physical discomfort, but also a space of comfort by the human competence, by the surrounding environment and by rapidly attention to the patient’s needs: The fourth analysis step consisted in synthesize all of the transformed meaning units into a consistent and descriptive statement regarding the subject’s experience of confort. P12 “If you need a nurse, a nurse will come immediately. If you need anything, just call them and they will come here straightaway. It is the comfort of knowing that if I need to call the nurses, they come here immediately.” According to Giorgi [30, 34, 35], how or where the meaning units are delineated is not absolute, different researchers may delineate the meaning units in different places in the same data. To ensure rigour, each authors performed individual analyses. Every step of analysis were compared and discussed to strengthen the validity of analysis. By making reference to these comfort factors, the infor- mants establish constant comparison with the experience lived in other services in which they were previously hospitalized: To manage the data was used the QSR NVivo version 10 software. P10 “I had never been in a facility with such human quality as this one. Here the staffs are attentive to everything, I mean everything. And always smiling”. Results The analysis of the findings allowed the access to a com- prehensive scheme (Fig. 1) organized in an interactive structure. Data collection Data were collected through non-structured inter- views. Interviews were chosen taking into account the vulnerability of participants [32]. Furthermore this technique facilitates a personal narrative by the participant [33]. Non-structured interviews were conducted, supported by the original question: How did you live the experience Page 3 of 8 Coelho et al. BMC Palliative Care (2016) 15:71 Page 3 of 8 Page 3 of 8 The patient’s vulnerable conditions constituted a limita- tion to the rigor of the study, since it was not possible to confirm the findings with the interviewees. Thus, during the interviews were performed cross-checks to clarify and confirm the coherence of the mentioned for patients in their reports. PCU. Participants were not acquainted to the researchers prior to the study commencements. They were made aware of the aim of the study, place of work and role of interviewer to inform their decision-making. Participation was voluntary and they were informed of their right to withdraw from the study at any time. Complete confidentiality was guaranteed and a written consent was obtained by the main researcher before each interview. Data analysis Consistent with Giorgi method [30, 34, 35], analysis involved four steps. The first step was a reading of transcripts, several times, to get a sense of the whole experience. This was done without a critical reflection on the experience. Posteriorly, in the second step, was performed a subsequent readings of the tran- scripts with the purpose of identify the meaning units (seccions of the collected data that could reveals po- tentials aspects of the phenomenon under investiga- tion). Each meaning unit is delimited by a change in the thematic content. Ethical considerations Ethical approval was obtained by the Research Ethics Committees of the Fundació d’Osona per a la Recerca i l’Educació Sanitària (reference 2015873), Arcebispo João Crisóstomo Hospital (04 February 2015) and Health Sciences Research Unit: Nursing (reference 228–10/2014). Participating organisations’ ethical re- quirements were met. P9 “It is a fact that here I have practically the same things as in the other hospital, my blood pressure is assessed, my medication is given to me. Nevertheless, here, besides it, there is a place where I can go down and go for a walk.” The interviewer works in the Spanish Center; however during the data collection period did not work in the Coelho et al. BMC Palliative Care (2016) 15:71 Page 4 of 8 Fig. 1 Conceptual representation of the sub-themes and themes based on the findings Fig. 1 Conceptual representation of the sub-themes and themes based on the findings P3 “The problem that I now have is a breathing one… I have difficulty even speaking…my body has given all it has got” P3 “The problem that I now have is a breathing one… I have difficulty even speaking…my body has given all it has got” P17 “This means a jail. It’s a prison to be locked here, a prison.” P17 “This means a jail. It’s a prison to be locked here, a prison.” P17 “This means a jail. It’s a prison to be locked here, a prison.” P14 “By saying: I am fine! The disease goes away quicker … “ P14 “By saying: I am fine! The disease goes away quicker … “ In the Spanish context, the loss of freedom, for some informants it relates to the fact that they have to share a room with another patient. quicker … “ Attempt to naturalize advanced disease Symptomatic control obtained through the hospitalization in PCU leads to some informants naturalized the ad- vanced disease, denying the proximity of death: P1 “Always the bedpan…I feel dependant. I am always waiting for someone to do everything for me.” P1 “(…) this is a temporary situation of one or two months which will end. This situation does not worry me, everyday I improve greatly and I am very positive.” P17 “(…) watch the land, listen to the birdies and look at the things I have…the yards, the trees… until this got to me in a stronger way and everything ended. To be comfortable is not to have anything, not to have any problem, it is to be at my home.” In this sense, they described a sense of hope regarding recovery and return home. P15 “My hope is to recover the least independence which I know is possible, so I can go home to my little dog and to my kittens.(…) I believe that there is always a tomorrow, that there is hope.” Informants of Portuguese PCU even describe as uncomfortable experience the loss of freedom, which corresponds with the lack of an exterior space intended for patients (this space exists in Spanish PCU and was described as comfort proportioning) The informant reports also reveal the conviction that it is possible to interfere with the course of the disease by the optimism: Openness to spiritual dimension The confrontation with their own vulnerability raises in some patients the opening to the relationship intraper- sonal, to the need to do a review of his personal history. The findings suggest that although some comfort in- terventions seem simple and of little technological com- plexity (such as availability, fondness, support), they had the ability to significantly affect the state of comfort. P14 “I believe I have not affected anybody…here we think about everything, we weigh everything, and here some things are left to be concluded and others left halfway.” Informants also make a clearly positive assessment of care received in PCU compared to other units in which they have already been admitted, stating that the PCU is a different human and environmental structure. Kolcaba [38, 39], to define environmental comfort makes reference to the environment and to internal and external conditions such as noise, light, temperature or natural elements. This time dedicated to the life review allows the re- valuation of what is really important. P10 “I lost too much time scolding my family…and today I can only think of that everything we lived was wonderful… We don’t regard things until they are lost.” Previous researches report the environment of the PCU [40, 41]. However, this study brings new data since pa- tients emphasize the PCU environment as evidence of the comfort experience through the external environment ad- justed (Spanish context) and reduced noise (Portuguese context). The setting was also described as a comfort fac- tor in the study of Hamilton [42], reported however to the presence of homelike elements to patients. During this process the world of relations contains a spe- cial importance. Thus, from the speech of the participants emerges comfort that comes from affection with peers, with friends, with family and with the professionals themselves. The satisfaction of needs that required hospitalization, leads to some patients try to naturalize advanced disease and make a denial of the proximity of death. P6 “I have a perfect partner. That means I can share with him my problems, that I can trust him as if he was my family.” According to Kubler-Ross “denial is usually a tempor- ary defence and will soon be replaced by partial accept- ance” [43] (p.39). The patient does not want to believe in what is happening, there is a threat that it is necessary to deny to continue living. Discussion In previous research under the comfort in PC, comfort often appears associated with the physical dimension of the person [7, 36, 37]. However, this study showed that in addition to physical symptoms, there are other fac- tors that promote significantly comfort and discomfort experiences of inpatients in PCU that should be taken into account. Due to those experienced losses and powerlessness that they generate, some informants sense the imminence of the end of life: P17 “That was why I was sent here… perhaps it was so that I could end my days in here… “ Therefore, informants recognize as comfort sources, technical competence and human competence with which they feel care in PCU. Confrontation with their own vulnerability P3 “I have a neighbour who wants the blinds always closed…I like to read the newspaper and because of that I can’t read and that also makes me feel uncomfortable.” Even if the PCU be recognized as an area that provide comfort, it is also seen as a discomfort space, where phys- ical and social losses, the feeling of helplessness, confronts informants with their vulnerability and finitude. Coelho et al. BMC Palliative Care (2016) 15:71 Page 5 of 8 Page 5 of 8 P9 “To be able to go outside for a walk is to inflate an internal joy which makes me feel alive.” The experience of all these losses generates impotence and devaluation feelings on the informants: P9 “To be able to go outside for a walk is to inflate an internal joy which makes me feel alive.” P17 “It is him (God) who comforts me, he is my saviour.” P14 “I feel inferior… I wanted to go alone (to the toilet) but I can’t. Asking for help means wanting and not being able to.” P17 “It is him (God) who comforts me, he is my saviour.” Conclusion The experience of comfort, in the patient’s perspective, has been ignored by the literature on PC. These findings indicate that experienced losses and the feeling of powerlessness to solve them are the main source of discomfort experienced by the informants. This study demonstrated that the PCU can be perceived as a space of comfort where the patient finds a suitable therapeutic context to their needs, but also as a place of discomfort where the patient is confronted with its vulner- ability. It can be a space where there is a process of de- nial or openness to spirituality. The discomfort has underlying the experienced losses and the inability to transcend. The patient feels comfortable through the symptomatic control, compassionate care, the PCU dif- ferentiated environment, hope, interpersonal, transper- sonal and intrapersonal relationships. Indeed, according Kolcaba [10], one dimension of com- fort is transcendence, defined as the state in which the person feels it has the potential to control their destiny, solve their problems. The discomfort allows informants to intuit their fini- tude, which could lead them to the denial but also to a personal growth. There is no social or biological restric- tion that is so powerful that can overcome the freedom to take a stand, the freedom to choose what attitude to adopt in the face of suffering [51]. Even if such findings may seem intuitive, documenting them is crucial because it invites the reader to reflect on their beliefs about what it means to be comfortable for these patients, and allows the incorporation of this infor- mation in the design of focused interventions to maximize the comfort experience. Unless one offers patients the opportunity to be heard on their experience, their per- spective will remain hidden and you could hardly provide comfort to them. Thus, some informants choose to open up to spiritu- ality, through intensification of the relationships and affections. Previous research in PC states that interper- sonal relationships are strengthened at the end of life [52]. Nevertheless this study provides a new under- standing by suggesting as comfort factors the intraper- sonal relationships (making a recapitulation of his life and an evaluation of what is really important), inter- personal (with professional, family and friends) but also transpersonal relationships (with God and nature), since these relationships generate love towards them- selves, others and the transcendent. Openness to spiritual dimension Thus, the informants speak about a future recovery. P15 “It is to feel loved, to feel nurtured, to feel spoiled.” (have friends visit) P17 “There is a moment which is special, which is my wife’s visit who comes here everyday.” This experiencing is congruent with findings obtained by Quill et al. [44], according to which one of the most important aspects to reach to the patient with advanced disease, would be the ability to change the trajectory of their illness. P9 “This team that cares us so well, with such kindness… I think that for a patient it is as important a good medication or treatment as it is a humanised and nurtured care.” The findings suggest that hope is a comfort factor, since patients trust that they still have some control over their health situation. Or even that it is possible to inter- fere with the course of the disease, as was also reported by other studies [45, 46]. The speech of patients also points to the comfort that comes from the relationship with the transcendent – with Nature and with God. Coelho et al. BMC Palliative Care (2016) 15:71 Page 6 of 8 Page 6 of 8 According to Broggy [47], sometimes denial is so intense that resists victoriously to the reason evidence, under surprising hopes. Nevertheless, the body, through physical losses that are becoming more evident, restrictive and generators of impotence, indicates every day more clearly what will be the end. itself, but also a sense of life that must be met or some- one to love. This study supports the experience of comfort and discomfort as a balanced process, in which there is an oscillation between the losses and the valorisation of re- lationships. If in a sense discomfort prevails, in other the intensification of the affections predominates. under surprising hopes. Nevertheless, the body, through physical losses that are becoming more evident, restrictive and generators of impotence, indicates every day more clearly what will be the end. As mentioned by Charmaz [48], there is a loss of iden- tity, a loss of the “self”. Likewise, Cassel [49], described suffering as the state of discomfort induced by the person disintegration threat. Even we mentioned the patient’s perspective, the major- ity of the interviewed (82 %) had cancer-related diagnoses, so the focus of the study was almost on palliative cancer patients. Openness to spiritual dimension As pointed out in our introduction, ageing popu- lations will lead to an increase in chronic conditions. Data indicates that these conditions could have a different dying trajectory than cancer [53]. Physical losses and lack of autonomy favor the experi- ences of psycho-spiritual discomfort, since the self-esteem of the patient is affected. Besides somatic vulnerability, informants are confronted with social vulnerability. The disease traps the patient and is a source of profound limitations, as the impossibility to return home. So, grouping the experience of all PC patients together (cancer/non-cancer) does not take these differences in comfort experience into account. We believe that our data covers the comfort experi- ences, but of course, the inclusion of more patients, with non-cancer diagnoses, and do the data analysis by separate in future research, might reveal additional relevant experiences. The fact of sharing a room represents, for some patients, social comfort, letting them share their ex- perience with other patients. For others, this is a dis- comfort factor since sharing a room deprives them of their freedom. These findings are consistent with the study of Williams y Gardiner [50], which states that PCU should have col- lective and single rooms since the choice between these two types of room is not unanimous among patients. Conclusion In addition, the findings provide useful information that leads us to two major future research lines: the need to de- velop and implement comfort interventions adapted and adjusted to these patients’ comfort needs; and the need to validate cross-culturally, to the contexts in study, an instrument for evaluating comfort, in order to assess the comfort interventions implemented. Indeed, Viktor Frankl [51], states that the core of the human being is the spirit, that is, the existence is always directed to something that is not only the very existence Page 7 of 8 Page 7 of 8 Page 7 of 8 Coelho et al. BMC Palliative Care (2016) 15:71 References 1. Worldwide Palliative Care Alliance. Global Atlas of Palliative Care at the End of Life. London: Worldwide Palliative Care Alliance; 2014. 1. Worldwide Palliative Care Alliance. Global Atlas of Palliative Care at the End of Life. London: Worldwide Palliative Care Alliance; 2014. 1. Worldwide Palliative Care Alliance. Global Atlas of Palliative Care at the End of Life. London: Worldwide Palliative Care Alliance; 2014. Additional file 1: COnsolidated criteria for REporting Qualitative research (COREQ): a 32-item checklist for interviews and focus groups. (DOCX 17 kb) 2. Tomás-Sábado J, Benito J. Variables relacionadas con la ansiedad ante la muerte. Rev Psicol Gen Apl. 2003;56(3):257–79. 2. Tomás-Sábado J, Benito J. Variables relacionadas con la ansiedad ante la muerte. Rev Psicol Gen Apl. 2003;56(3):257–79. muerte. Rev Psicol Gen Apl. 2003;56(3):257–79. 3. Twycross RG. Palliative Care: An international necessity. J Pain Palliat Care Pharmacother. 2002;16(1):61–79. 3. Twycross RG. Palliative Care: An international necessity. J Pain Palliat Care Pharmacother. 2002;16(1):61–79. 4. Currow DC, Ward AM, Plummer JL, Bruera E, Abernethy AP. Comfort in the last 2 weeks of life: relationship to accessing palliative care services. Support Care Cancer. 2008;16(11):1255–63. Availability of data and material Not apply. 10. Kolcaba K. A theory of holistic comfort for nursing. J Adv Nurs. 1994;19(6): 1178–84. Acknowledgements 6. Printz LA. Is withholding hydration a valid comfort measure in the terminally ill? Geriatrics. 1988;43(11):84–8. The authors would like to thank the Health Sciences Research Unit: Nursing, Nursing School of Coimbra School (Portugal), Santa Creu de Vic Hospital (Spain) and Arcebispo Joao Crisóstomo Hospital (Portugal). terminally ill? Geriatrics. 1988;43(11):84–8. 7. LeGrand SB, Walsh D. Comfort Measures: Practical Care of the Dying Cancer Patient. Am J Hosp Palliat Med. 2010;27(7):488–93. 7. LeGrand SB, Walsh D. Comfort Measures: Practical Care of the Dying Canc Patient. Am J Hosp Palliat Med. 2010;27(7):488–93. Patient. Am J Hosp Palliat Med. 2010;27(7):488–93. 8. Oliveira I. Comfort measures: a concept analysis. Res Theory Nurs Pract. 2013;27(2):95–114. 8. Oliveira I. Comfort measures: a concept analysis. Res Theory Nurs Pract. 2013;27(2):95–114. Abbreviations PCU, palliative care unit; PC, palliative care; COREQ, cOnsolidated criteria for reporting qualitative research. . Novak B, Kolcaba K, Steiner R, Dowd T. Measuring comfort in caregi 5. Novak B, Kolcaba K, Steiner R, Dowd T. Measuring comfort in caregivers and patients during late end-of-life care. Am J Hosp Palliat Care. 2001;18(3):170–80. Authors’ contribution 11. Morse JM. An ethnoscientific analysis of comfort: a preliminary investigation. Nurs Pap. 1983;15(1):6–20. AC, VP, JA, and MEB designed the study. AC conducted and transcribed all the interviews. AC and VP analysed the data and drafted the manuscript. All authors contributed to data analysis and helped in revising and making substantial contributions to the manuscript, and also read and approved the final manuscript. 12. Hamilton J. Comfort and the hospitalized chronically ill. J Gerontol Nurs. 1989;15(4):28–33. 13. Neves Arruda EN, Larson PJ, Meleis AI. Comfort. Immigrant Hispanic cancer patients’ views. Cancer Nurs. 1992;15(6):387–94. 14. Tutton E, Seers K. Comfort on a ward for older people. J Adv Nurs. 2004; 46(4):380–9. Ethics approval and consent to participate Ethical approval was obtained by the Research Ethics Committees of the Fundació d’Osona per a la Recerca i l’Educació Sanitària (reference 2015873), Arcebispo João Crisóstomo Hospital (04 February 2015) and Health Sciences Research Unit: Nursing (reference 228–10/2014). Participating organisations’ ethical requirements were met. 24. Jones JM, McPherson CJ, Zimmermann C, Rodin G, Le LW, Cohen SR. Assessing agreement between terminally ill cancer patients’ reports of their quality of life and family caregiver and palliative care physician proxy ratings. J Pain Symptom Manage. 2011;42(3):354–65. ratings. J Pain Symptom Manage. 2011;42(3):354–65. Participation was voluntary and they were informed of their right to withdraw from the study at any time. Complete confidentiality was guaranteed and a written consent was obtained by the main researcher before each interview. 25. Field D, Douglas C, Jagger C, Dand P. Terminal illness: views of patients and their lay carers. Palliat Med. 1995;9(1):45–54. 26. Milne DJ, Mulder LL, Beelen HCM, Schofield P, Kempen GIJM, Aranda S. Patients’ self-report and family caregivers’ perception of quality of life in patients with advanced cancer: How do they compare? Eur J Cancer Care (Engl). 2006;15(2):125–32. Consent for publication Not apply. 22. McMillan SC, Moody LE. Hospice patient and caregiver congruence in reporting patients’ symptom intensity. Cancer Nurs. 2003;26(2):113–8. 23. Redinbaugh EM, Baum A, DeMoss C, Fello M, Arnold R. Factors associated with the accuracy of family caregiver estimates of patient pain. J Pain Symptom Manage. 2002;23(1):31–8. Authors’ information AC, RN., MD. of Palliative Care, MD in Health Research, PhD. Student. Guest Assistant at the Nursing School of Coimbra (EsenfC). Collaborate Research at the Portugal Centre for Evidence-Based Practice (PCEBP): a Collaborating Centre of the Joanna Briggs Institute - Health Sciences Research Unit: Nursing (UICISA: E). VP, RN., MD. of Palliative Care, MD in Health Research, PhD. Student. Guest Assistant at the Nursing School of Coimbra (EsenfC). Collaborate Research at the Portugal Centre for Evidence-Based Practice (PCEBP): a Collaborating Centre of the Joanna Briggs Institute - Health Sciences Research Unit: Nursing (UICISA: E). 15. Waldrop DP, Kirkendall AM. Comfort measures: a qualitative study of nursing home-based end-of-life care. J Palliat Med. 2009;12(8):719–24. 16. Fleming C, Scanlon C, D’Agostino NS. A study of the comfort needs of patients with advanced cancer. Cancer Nurs. 1987;10(5):237–43. 17. Bottorff JL, Gogag M, Engelberg-Lotzkar M. Comforting: exploring the work of cancer nurses. J Adv Nurs. 1995;22(6):1077–84. 18. Searle C, Mcinerney F. Creating comfort: Nurses’ perspectives on pressure care management in the last 48 hours of life. Contemp Nurse. 2008;29(2):147–58. MEB, RN., PhD. Professor, University of Lleida, Faculty of Nursing and Physiotherapy, Lleida, Spain. MEB, RN., PhD. Professor, University of Lleida, Faculty of Nursing and Physiotherapy, Lleida, Spain. MEB, RN., PhD. Professor, University of Lleida, Faculty of Nursing and Physiotherapy, Lleida, Spain. 19. Addington-Hall J, McPherson C. After-Death Interviews with Surrogates/ Bereaved Family Members. J Pain Symptom Manage. 2001;22(3):784–90. JA, RN., PhD. Professor, Health Sciences Research Unit: Nursing, Nursing School of Coimbra, The Portugal Centre for Evidence-Based Practice: an Affiliate Centre of the Joanna Briggs Institute. Coimbra, Portugal. JA, RN., PhD. Professor, Health Sciences Research Unit: Nursing, Nursing School of Coimbra, The Portugal Centre for Evidence-Based Practice: an Affiliate Centre of the Joanna Briggs Institute. Coimbra, Portugal. 20. Lynn J, Teno JM, Phillips RS, Wu AW, Desbiens N, Harrold J, et al. Perceptions by family members of the dying experience of older and seriously ill patients. SUPPORT Investigators. Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments. Ann Intern Med. 1997;126(2):97–106. Competing interests p g The authors declared that they have no competing interests. 21. Lobchuk MM, Degner LF. Symptom experiences: Perceptual accuracy between advanced-stage cancer patients and family caregivers in the home care setting. J Clin Oncol. 2002;20(16):3495–507. Funding No funding was obtained. 9. Kamal AH, Gradison M, Maguire JM, Taylor D, Abernethy AP. Quality Measures for Palliative Care in Patients With Cancer: A Systematic Review. J Oncol Pract. 2014;10(4):281–7. Received: 1 December 2015 Accepted: 27 July 2016 Coelho et al. BMC Palliative Care (2016) 15:71 Author details 1 Dying trajectories in heart failure. Palliat Med. 2007;21(2):95–9. 53. Gott M, Barnes S, Parker C, Payne S, Seamark D, Gariballa S, et al. Dying trajectories in heart failure. Palliat Med. 2007;21(2):95–9. Author details 1 1Nursing School of Coimbra, Coimbra, Portugal. 2University of Lleida, Faculty of Nursing and Physiotherapy, Lleida, Spain. 3Health Sciences Research Unit: Nursing, Nursing School of Coimbra, The Portugal Centre for Evidence-Based Practice: an Affiliate Centre of the Joanna Briggs Institute, Coimbra, Portugal. 27. Spiller JA, Alexander DA. Domiciliary care: a comparison of the views of terminally ill patients and their family caregivers. Palliat Med. 1993;7(2):109–15. 28. Vendlinski S, Kolcaba K. Comfort care: A framework for hospice nursing. J Hosp Palliat Care. 1997;14(6):271–6. Received: 1 December 2015 Accepted: 27 July 2016 29. Kolcaba K. Comfort Theory and Practice: A Vision for Holistic Health Care and Research. New York: Springer Publishing Company; 2003. Page 8 of 8 Page 8 of 8 Coelho et al. BMC Palliative Care (2016) 15:71 30. Giorgi A. The Theory, Practice, and Evaluation of the Phenomenological Method as a Qualitative Research Procedure. J Phenomenol Psychol. 1997; 28(2):235–60. 31. Marshall MN. Sampling for qualitative research. Fam Pract. 1996;13(6):522–6 32. Rubiales AS, Del Valle ML, Flores LA, Hernansanz S, Gutiérrez C. ¿Cómo podemos adaptar la metodología de la investigación clínica a los Cuidados Paliativos? Med Paliativa. 2007;14(4):243–9. 33. Seymour J, Clark D. Phenomenological approaches to palliative care research. Palliat Med. 1998;12(2):127–131. 33. Seymour J, Clark D. Phenomenological ap research. Palliat Med. 1998;12(2):127–131. 33. Seymour J, Clark D. Phenomenological approaches to palliativ research. Palliat Med. 1998;12(2):127–131. 34. Giorgi A. Concerning the application of phenomenology to caring research. Scand J Caring Sci. 2000;14(1):11–5. Scand J Caring Sci. 2000;14(1):11–5. 35. Giorgi A. Concerning Variations in the Application of the Phenomenological Method. Humanist Psychol. 2006;34(4):305–19. Method. Humanist Psychol. 2006;34(4):305–19. 36. Jack B, Hillier V, Williams A, Oldham J. Hospital based palliative care teams improve the symptoms of cancer patients. Palliat Med. 2003;17(6):498–502. 36. Jack B, Hillier V, Williams A, Oldham J. Hospital based palliative care teams improve the symptoms of cancer patients. Palliat Med. 2003;17(6):498–502. 37. Jack B, Hillier V, Williams A, Oldham J. Improving cancer patients’ pain: The impact of the hospital specialist palliative care team. Eur J Cancer Care (Engl). 2006;15(5):476–80. 38. Kolcaba KY. A taxonomic structure for the concept comfort. Imagen J Nurs Sch. 1991;23(4):237–40. 39. Kolcaba KY. Holistic comfort: Operationalizing the co sensitive outcome. Adv Nurs Sci. 1992;15(1):1–10. sensitive outcome. Adv Nurs Sci. 1992;15(1):1–10. 40. Ingleton C. The views of patients and carers on one palliative care service. Int J Palliat Nurs. 1999;5(4):187–95. 40. Ingleton C. Author details 1 The views of patients and carers on one palliative care service. Int J Palliat Nurs. 1999;5(4):187–95. 41. Mckinlay EM. Within the circle of care: Patient experiences of receiving palliative care. J Palliat Care. 2001;17(1):22–9. palliative care. J Palliat Care. 2001;17(1):22–9. 42. Hamilton J. Comfort on a Palliative Care Unit: The cliente’s Percept Toronto, Canada: McGill University; 1985. 42. Hamilton J. Comfort on a Palliative Care Un Toronto, Canada: McGill University; 1985. 43. Kübler-Ross E. On death and dying: What the Dying Have to Teach Doctors Nurses, Clergy and Their Own Families. New York: Scribner; 2014. Nurses, Clergy and Their Own Families. New York: Scribner; 20 44. Quill T, Norton S, Shah M, Lam Y, Fridd C, Buckley M. What is Most Important for You to Achieve?: An Analysis of Patient Responses When Receiving Palliative Care Consultation. J Palliat Med. 2006;9(2):382–8. Receiving Palliative Care Consultation. J Palliat Med. 2006;9(2):382–8. 45. Benzein E, Norberg A, Saveman BI. The meaning of the lived experience of hope in patients with cancer in palliative home care. Palliat Med. 2001;15(2):117–26. 46. Fryback PB. Health for People With a Terminal Diagnosis. Nurs Sci Q. 1993; 6(3):147–59. 47. Broggi MA. Por una muerte apropiada. Barcelona: Anagrama; 2013. 48. Charmaz K. ‘Discovering’ chronic illness: Using grounded theory. Soc Sci Med. 1990;30(11):1161–72. 49. Cassell E. The nature of suffering and the goals of Medicine. 2ath ed. Oxford: Oxford University Press; 2004. 49. Cassell E. The nature of suffering and t Oxford: Oxford University Press; 2004. 49. Cassell E. The nature of suffering and the goals of Medicine. Oxford: Oxford University Press; 2004. 50. Williams C, Gardiner C. Preference for a single or shared room in a UK inpatient hospice: patient, family and staff perspectives. BMJ Support Palliat Care. 2015;5(2):169–74. 50. Williams C, Gardiner C. Preference for a single or shared room in a UK inpatient hospice: patient, family and staff perspectives. BMJ Support Palliat Care. 2015;5(2):169–74. 51. Frankl VE. El hombre en busca de sentido. 12a edició. Barcelona: Editorial Herder; 1991. 51. Frankl VE. El hombre en busca de sentido. 12a edició. Barcelona: Editorial Herder; 1991. 52. Prince-Paul M. Understanding the meaning of social well-being at the end of life. Oncol Nurs Forum. 2008;35(3):365–71. 52. Prince-Paul M. Understanding the meaning of social well-being at the end of life. Oncol Nurs Forum. 2008;35(3):365–71. 53. Gott M, Barnes S, Parker C, Payne S, Seamark D, Gariballa S, et al. 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Latitudinal changes of euphausiid assemblages related to the morphological variability of the sound scattering layer along Baja California, October 1994
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Latitudinal changes of euphausiid assemblages related to the morphological variability of the sound scattering layer along Baja California, October 1994* J. GÓMEZ-GUTIÉRREZ1, G. GONZÁLEZ-CHÁVEZ2, C.J. ROBINSON2, and V. ARENAS-FUENTES2 1Departamento de Plancton y Ecología Marina, Centro Interdisciplinario de Ciencias Marinas Apartado Postal 592, C.P. 23000 La Paz, Baja California Sur, México 1Current address: College of Oceanic and Atmospheric Sciences, Oregon State University, 104 Ocean. Admin. Building. Corvallis, OR 97331-5503, USA 2Laboratorio de Ecología de Pesquerías, Instituto de Ciencias del Mar y Limnología, UNAM Apartado Postal 70-305, C.P. 04510. México, D.F., México 1Departamento de Plancton y Ecología Marina, Centro Interdisciplinario de Ciencias Marinas Apartado Postal 592, C.P. 23000 La Paz, Baja California Sur, México 1Current address: College of Oceanic and Atmospheric Sciences, Oregon State University, 104 Ocean. Admin. Building. Corvallis, OR 97331-5503, USA 2Laboratorio de Ecología de Pesquerías, Instituto de Ciencias del Mar y Limnología, UNAM Apartado Postal 70-305, C.P. 04510. México, D.F., México SUMMARY: Latitudinal changes in the euphausiid assemblages were compared to the morphological structure (size and compactness) of the sound scattering layer (SSL) during ten 24-h surveys made in October 1994 along the west coast of Baja California, México. During October, upwelling was found in the northern area from Punta Eugenia (28°N) to Ensena- da (30°N) dominated by temperate species from the California Current System. In the southern sector of the peninsula, a northward movement of tropical waters transports a tropical zooplankton assemblage near Bahia Magdalena (24°N). The aggregation and the dispersion of the whole SSL (plankton and nekton) were investigated using a single beam vertical echosounder, Simrad EY-200, working at 200 kHz and the Hydro Acoustic Data Acquisition System (HADAS) that esti- mates patch variables of density and compactness. The size and shape of the SSL were obtained from the echogram visual- ization. The euphausiid species composition was obtained using an Isaacs-Kidd midwater trawl, bongo nets, and opening- closing nets. At Ensenada and Punta Eugenia, an area inhabited by a temperate euphausiid assemblage, large and dense SSLs were recorded over the continental shelf (mean sizes were 10-km and 7-km long with mean compactness of 15% and 19%). These regions were dominated by the neritic species Nyctiphanes simplex and the temperate species Nematoscelis difficilis, Euphausia pacifica, and Thysanoessa spinifera. In the southern area, a tropical euphausiid assemblage, dominated by Euphausia eximia, E tenera, and E. distinguenda, inhabits smaller and dispersed SSLs (mean size 5-km long and 11% com- pactness) located in the offshore area. The euphausiid biomass of the most abundant species indicated, N. simplex and N. SCIENTIA MARINA SCIENTIA MARINA SCI. MAR., 63 (1): 79-91 1999 Latitudinal changes of euphausiid assemblages related to the morphological variability of the sound scattering layer along Baja California, October 1994* difficilis, had their highest standing stock in the north (393 and 643 mg C 1000 m-3), with E. eximia in the southern area (186 mg C 1000 m-3). Euphausiid assemblage development in different biological environments, is evidenced by SSL morphol- ogy along the west coast of Baja California during autumn, is caused by strong latitudinal changes in physical oceanogra- phy that affect the biological interactions in each region. Key words: Euphausiids, sound scattering layer, Baja California.. *Received February 18, 1998. Accepted November 12, 1998. 1Departamento de Plancton y Ecología Marina, Centro Interdisciplinario de Ciencias Marinas Apartado Postal 592, C.P. 23000 La Paz, Baja California Sur, México 1Current address: College of Oceanic and Atmospheric Sciences, Oregon State University, 104 Ocean. Admin. Building. Corvallis, OR 97331-5503, USA 2Laboratorio de Ecología de Pesquerías, Instituto de Ciencias del Mar y Limnología, UNAM Apartado Postal 70-305, C.P. 04510. México, D.F., México MATERIAL AND METHODS An insight into the behavior within and between SSLs is important to understand the function of the epipelagic ecosystem. The analysis of echograms provides morphological descriptions of plankton and fish aggregations together with characteristics of their habitat. However, most studies have been made with fish schools (Misund, 1993; Misund et al., 1995; Petigas and Levenez, 1996; Massé et al., 1996). Studies of the SSL using nonintrusive tech- niques (hydroacoustic) may give clues to the link between euphausiids, the environment, and the rest of the pelagic community. Data were collected along the west coast of Baja California, México from October 17 to 30, 1994 on the RV ‘El Puma’. Ten 18-km transects perpendicu- lar to the coast, covering three areas, were sampled: north, from Ensenada to Punta Baja; center, from Punta Eugenia to Bahia Asuncion; and south, near Bahia Magdalena (Fig. 1). The transects covered three zones each approximately 6-km long: neritic, slope, and oceanic. Along each transect, there were three oceanographic stations, one at each end and one in the middle (slope zone) (Fig. 1). Each tran- Along the west coast of Baja California, a strong latitudinal environmental gradient occurs during autumn (Gómez-Gutiérrez et al., 1996, Gómez- Gutiérrez and Robinson, 1997). Because it is known that zooplankton assemblages have latitudinal changes along Baja California during this season (i. e. Brinton, 1962, 1979; Gómez-Gutiérrez et al., 1995, Gómez-Gutiérrez and Robinson, 1997), an interesting comparative study can be performed of the aggrega- tion behavior of the SSLs of temperate and tropical epipelagic assemblages. We hypothesize that temper- ate and tropical euphausiid community structures inhabit SSLs with different morphological character- istics (i.e. shape, size, and compactness). One of the most important goals of the study of the dynamics of the SSL is the development of models that include animal behavior and environmental factors control- ling this behavior. Field sampling on fine horizontal (i.e. < 10 km) and vertical scales is important for understanding patch phenomena. Model studies of small regions on fine horizontal scales may help determine how to include the effects of patches in models with coarser spatial resolution. FIG. 1. – Map of the study area, indicating the sampling stations covered during October 1994. E = Ensenada; PB = Punta Baja (northern zone, transects 1 to 4); PE = Punta Eugenia (central zone; transects 1 to 4); BM = Bahia Magdalena (southern zone, transect 1 and 2). FIG. 1. INTRODUCTION related to euphausiid distribution, abundance, and community structure have been studied extensively in the California Current System and Eastern Tropi- cal Pacific (i.e. Brinton, 1962, 1979; Gómez-Gutiér- rez, 1995; Gómez-Gutiérrez et al., 1995). However, little attention has been given to the biological inter- actions between these assemblages and the rest of the pelagic community. Euphausiids typically play a major role in the economy of the pelagic food web in oceanic and coastal waters. Physical and chemical variables LATITUDINAL CHANGES OF EUPHAUSIIDS ASSEMBLAGES 79 LATITUDINAL CHANGES OF EUPHAUSIIDS ASSEMBLAGES 79 We designed a sampling program to detect changes on a circadian time scale over about 18 kilometers of the SSL along the Baja California peninsula. The aim of this study was to determine if observed latitudinal changes in the euphausiid com- munity structure during October 1994 (autumn) alters according to the physical characteristics of the SSL along the west coast of Baja California, a region recognized as a transition zone of the Cali- fornia Current System. Studies employing both net sampling and remote techniques could help resolve the spatial and temporal dependence of species dis- tribution, particularly vertical, on an ecosystem scale. In the marine pelagic environment, planktonic and nektonic organisms form dense aggregations, hydroacoustically recognized as a Sound Scattering Layer (SSL). This is defined as the layer where a large number of pelagic organisms reflect the hydroacoustic signals. The SSLs are dynamic, active, and have a particular behavior as a function of their community structure causing changes in their vertical distribution, size, and shape over time and space. These variable structures could imply different biological interactions among their compo- nents. Pelagic organisms generally form tight aggre- gations during the day, often near the seabed, and break into less dense aggregations that are more amenable to acoustic observation at night when they move into midwater (Isaacs and Schwartzlose, 1965; Robinson and Gómez-Gutiérrez, 1998). MATERIAL AND METHODS – Map of the study area, indicating the sampling stations covered during October 1994. E = Ensenada; PB = Punta Baja (northern zone, transects 1 to 4); PE = Punta Eugenia (central zone; transects 1 to 4); BM = Bahia Magdalena (southern zone, transect 1 and 2). 80 J. GÓMEZ-GUTIÉRREZ et al. strengths (MacLennan and Simmonds, 1992), this echo-strength range was used based on i) results obtained in more than 400 Isaacs-Kidd mid-water trawls that we have made along the west coast of Baja California since 1992, and ii) compared the catches with echo-analysis obtained using the same frequency, the same calibrated echosounder, and the same variables to acquire hydroacoustic data. Accordingly, this target strength corresponds to zoo- plankton aggregations, mainly euphausiids, which are common in the area (Gómez-Gutiérrez, 1995, Gómez-Gutiérrez and Robinson, 1997; Robinson and Gómez-Gutiérrez, 1998). With this range, we were able to discriminate fish and other larger nek- tonic animals. Therefore, the rest of the TS range (- 32 to -52) was neglected in the statistical analyses. When the zooplankton abundance was high enough to be detected by the echo sounder, the acoustic technique detected and quantified the backscattering strength and distribution of the organisms with more detail than is possible with net sampling. Hydroa- coustic information, therefore, enabled us to map the vertical and horizontal zooplankton distribution continuously during 24 h. sect was monitored for approximately 24 hours, starting from the neritic station, heading to the oceanic, returning to the middle station and finish- ing at the neritic station about 4 h later. The loop was repeated for a total time of 24 h. About six samples (Bongo and CTD) per oceanographic station and about 18 samples per transect were taken. p p A continuous hydroacoustic survey of the water column was obtained along each transect. We used a single-beam echosounder, Simrad EY-200 (nominal beam width 7°) with a working frequency of 200 kHz, an average ping rate of 1.7 pulses per second, and a pulse duration of 0.3 ms was used. The trans- ducer depth was 4 m and the echo analysis started 1 m from the transducer. Before the cruise, calibration was done using a standard target, a 13-mm diameter copper sphere (-45 decibels dB). To analyze the echosounder information, the Hydro Acoustic Data Acquisition System (HADAS) was used (Lindem and Houri, 1988). HADAS processes hydroacoustic data in several steps. MATERIAL AND METHODS First, data are digitized and stored in a data file, later they can be displayed as an echogram and analyzed. This system is an echo- counting program that transforms the received echo distribution into area densities and abundance esti- mates. HADAS uses the Craig and Forbes (1969) algorithm to remove the beam pattern effect. A modified Isaacs-Kidd mid-water trawl net (a cod end liner of 500-µm mesh with a 2.5- x 2.5-m mouth area) was trawled between stations where dense SSLs occurred to determine the euphausiid species composition. Along each transect, water temperature and salinity were recorded at each oceanographic station using a CTD Inter-Ocean SO4 (from the surface to 200 m). Zooplankton sam- ples were collected at each station using Bongo nets fitted with 300- and 500-µm mesh obliquely towed from 200 m to the surface (or 10 m from the bottom in more shallow stations). At selected stations, an opening-closing net was trawled at three levels (above, within, and below the thermocline) to detect if the community structure of the shoal is different at these layers. The volumes filtered were estimated using a flowmeter. g p The hydroacoustic system is able to detect echoes between -32 to -57 dB and because a time- varied gain of 40 was used, an analysis of echo counts for individuals was done. Results are pre- sented as individuals per hectare (ind ha-1). More- over, using HADAS it is possible to obtain the num- ber of echoes found as single organism and, there- fore, calculates the degree of compactness of the scattering layer. The threshold for a single target is set arbitrarily by the user, but it depends on sound speed, pulse duration in seconds, and the corre- sponding length of the pulse in meters. In our case, the working pulse duration was 0.3 ms and the sound speed was 1500-m s-1. The pulse length in the water at any instant was 45 cm. We set ten as the threshold for single targets. That is, if a target lasted for less than 10 echoes it was considered to be a sin- gle organism. If it lasted for more, the target was considered a group. Results of compactness were then presented as the percentage of the total number of grouped echoes that were found. Environmental conditions The temperature-salinity (T-S) diagrams from the neritic and oceanic zones in the three latitudinal areas are shown in Figure 2. Strong latitudinal changes were evident along the west coast of Baja California. Surface waters of the California Current dominated the northern area with temperatures <18 °C and salinity < 33.4 ppt in the 50-m surface layer, the salinity increasing to about 34.3 ppt in deeper waters. The environmental conditions from the ner- itic and oceanic stations were quite different with lower temperature and slightly more saline water inshore indicating upwelling near shore. The decrease in minimum subsurface salinity can be assumed to be caused by the greater influence of California Current waters. In the center area, the 50- m layer was warmer (18 to 20 °C) and saltier (about 34.6 ppt) than the northern area. Like the north, in the center zone a neritic-oceanic gradient was evi- dent. A body of cool water was present inshore between 27° and 30°N, a feature perhaps indicative of recent upwelling. The southern area showed a marked influence of the Equatorial surface water mass with warmer surface waters (24-25 °C within FIG 2. – Representative temperature-salinity (T-S) diagrams for dif- ferent latitudinal zones, North = Ensenada; Center = Punta Eugenia, and South = Bahia Magdalena during October 1994. At each latitu- dinal zone, a neritic and an oceanic CTD vertical profile at night and another two during the day were chosen. the first 25 m) corresponding to surface Equatorial waters (Fig. 2). MATERIAL AND METHODS The zooplankton biomass was measured as dis- placement volume and was analyzed using multifac- tor analysis of variance for latitudinal, cross-shelf, and day vs. night patterns. All euphausiids from the 500-µm Bongo net were sorted from the samples, identified to species level, and counted. Numbers were standardized to individuals per 1000 m-3 and log-transformed to normalize them. Euphausiid species were grouped by biogeographic affinities following the classification of Brinton (1979). A cluster analysis (1-Pearson r using weighted pair- All the hydroacoustical analyses were made using target strengths measuring -53 to -57 dB. Although the use of a single beam echosounder is not the best method to calculate accurate target LATITUDINAL CHANGES OF EUPHAUSIIDS ASSEMBLAGES 81 FIG 2. – Representative temperature-salinity (T-S) diagrams for dif- ferent latitudinal zones, North = Ensenada; Center = Punta Eugenia, and South = Bahia Magdalena during October 1994. At each latitu- dinal zone, a neritic and an oceanic CTD vertical profile at night and another two during the day were chosen. group average) was used to determine the grouping based on the presence or absence of species using only samples obtained at night (2000 to 0500) because euphausiids are known to avoid nets during the day. Euphausia diomedeae Ortmann was the only species not included in the analysis because this was caught only during the day. The total length (from the posterior of the eye to the end of the telson, not including the spines) of all stages of the three most abundant euphausiid species was measured (Nyctiphanes simplex, Nematoscelis difficilis, and Euphausia eximia). To estimate euphausiid biomass in each region, the average body weight by size of these species was estimated as body carbon weight (mg C 1000 m-3) calculated from dry-weight equations reported by Gómez- Gutiérrez and Robinson (1997) (Nyctiphanes sim- plex DW = 0.005371 (TL)2.31596, Nematoscelis diffi- cilis DW = 0.001892 (TL)2.87750, and Euphausia eximia DW = 0.001057 (TL)3.10037, where DW is dry weight in mg and TL is total length in mm by assuming a carbon content of 45% (Parsons et al., 1984). Community structure of the euphausiids difficilis, and Stylocheiron affine, the euphausiid composition in the three latitudinal regions showed strong latitudi- nal differences (Table 1). Nineteen euphausiid species were caught in the Bongo trawls, showing a higher diversity than the Isaacs-Kidd net trawls. However, similar latitudinal trends in community structure of the euphausiids were observed. Changes in the species list were noted between latitudinal regions, and the relative abundance of species varied (Table 2). For example, Nyctiphanes simplex had its highest abundance when caught with a Bongo net in the north area, decreasing toward the south. Whereas, the catch using the Isaacs-Kidd net had its highest abundance in the cen- ter area. Nematoscelis difficilis abundance peaked in the north area using the bongo nets, but it was pre- sent only in the center area when caught in the LATITUDINAL CHANGES OF EUPHAUSIIDS ASSEMBLAGES 83 TABLE 2. – Average of sea surface temperature (°C), zooplankton biomass (ml 1000-3), and abundance (ind 1000 m-3) of the euphausiids obtained by Bongo net trawls along the west coast of Baja California, México. Relative abundance is shown in parentheses. * = abundance < 0.005 ind 1000 m-3. Community structure of the euphausiids Zooplankton samples from the Isaacs-Kidd midwater net trawls were dominated by seven euphausiid species (Table 1). All the other four euphausiid species were less than 8% of the total euphausiid abundance and, therefore, were grouped. Nyctiphanes simplex was the most abun- dant euphausiid collected with net gear in the north and central area and the second most abundant in the southern area, after Euphausia eximia. Using biogeographical affinities proposed by Brinton (1979), we found the north and central zones dom- 82 J. GÓMEZ-GUTIÉRREZ et al. TABLE 1. – Average density (ind dm-3) of the euphausiid species obtained by Isaacs-Kidd net trawls along the west coast of Baja California, México during October 1994. Relative abundance (%) is shown in parentheses, n = number of Isaacs-Kidd trawls analyzed, and * = species found in only one sample. TABLE 1. – Average density (ind dm-3) of the euphausiid species obtained by Isaacs-Kidd net trawls along the west coast of Baja California, México during October 1994. Relative abundance (%) is shown in parentheses, n = number of Isaacs-Kidd trawls analyzed, and * = species found in only one sample. TABLE 1. – Average density (ind dm-3) of the euphausiid species obtained by Isaacs-Kidd net trawls along the west coast of Baja California, México during October 1994. Relative abundance (%) is shown in parentheses, n = number of Isaacs-Kidd trawls analyzed, and * = species found in only one sample. Species North (n = 5) Center (n = 5) South (n = 6) Average SD Average SD Average SD Nyctiphanes simplex 4049 (84.57) 1844 7625 (60.02) 13603 4206 (40.65) 6626 Thysanoessa spinifera 333 (6.95) * Nematoscelis difficilis 266 (2.09) * Nematobrachion flexipes 66 (0.51) * Euphausia pacifica 3730 (29.36) 4804 Euphausia eximia 266 (2.09) * 5183 (50.08) 7477 Euphausia tenera 466 (4.51) * Others species (four) 406 (8.48) 409 753 (5.93) 879 493 (4.76) 445 inated by the marginal eastern tropical Pacific pro- liferator (ETP) N. simplex; three temperate Califor- nia Current terminus species, (Nematoscelis diffi- cilis, Thysanoessa spinifera, and Euphausia pacifi- ca) and several species of the offshore section of the California Current. In the southern zone, N. simplex and Euphausia eximia, another marginal ETP proliferator species, dominated, followed by two tropical and equatorial endemic ETP-adapted species (Euphausia tenera and Euphausia dis- tinguenda). Excluding N. simplex, N. TABLE 2. – Average of sea surface temperature (°C), zooplankton biomass (ml 1000-3), and abundance (ind 1000 m-3) of the euphausiids obtained by Bongo net trawls along the west coast of Baja California, México. Relative abundance is shown in parentheses. * = abundance < 0.005 ind 1000 m-3. Community structure of the euphausiids Abundance is expressed as individuals per hectare using a target strength range between - 53 to -57 dB. n = number of echograms analyzed. Zone and Transect Day Night Day and Night Relative ind ha-1 ind ha-1 ind ha-1 abundance (%) North 1 (n=6) 916 1910 2826 1.3 North 2 (n=7) 11416 18800 30216 14.1 North 3 (n=7) 95521 91852 187373 84.6 Mean 35951 37521 73472 55.4 Center 1 (n=6) 7969 18058 26027 15.5 Center 2 (n=6) 16966 13580 30546 18.3 Center 3 (n=7) 8744 17084 25828 15.5 Center 4 (n=6) 40030 44949 84979 50.7 Mean 18427 23418 41845 31.5 South 1 (n=7) 7428 8414 13846 43.3 South 2 (n=5) 2654 16219 18118 56.7 Mean 5041 12317 17358 13.1 Isaacs-Kidd net. This indicates the different catch efficiency of the different nets (Table 1 and 2). How- ever, these nets were not used in the same areas. The Bongo nets were used at each of the oceanographic stations, and the Isaacs-Kidd mid-water net was used between the oceanographic stations. Cluster analysis, using data only obtained during the night (2000 to 0500), showed three groups related to the three lati- tudinal sampling areas. Two groups, the center (except one northerly station) and southern areas, were independent. The third group was dominated by all the stations of the northern zone and the nine stations of the center zone (these last were located in transects C1 and C2 near the coast), suggesting an Isaacs-Kidd net. This indicates the different catch efficiency of the different nets (Table 1 and 2). How- ever, these nets were not used in the same areas. The Bongo nets were used at each of the oceanographic stations, and the Isaacs-Kidd mid-water net was used between the oceanographic stations. Cluster analysis, using data only obtained during the night (2000 to 0500), showed three groups related to the three lati- tudinal sampling areas. Two groups, the center (except one northerly station) and southern areas, were independent. The third group was dominated by all the stations of the northern zone and the nine stations of the center zone (these last were located in transects C1 and C2 near the coast), suggesting an overlapping of species from both areas (Fig. 3). A temperate California Current terminus assemblage dominated in the northern area, and a marginal ETP proliferator and an endemic ETP-adapted species dominated in the southern zone. Community structure of the euphausiids Zone North (29-31°N) Center (26-28° N) South (24-25°N) Day (n = 41) Night (n = 27) Day (n = 44) Night (n = 33) Day (n = 20) Night (n = 17) SST 18.12 17.83 20.32 19.99 25.34 25.21 Biomass 500 µm 40.33 47.00 63.35 74.02 19.98 29.87 Biomass 300 µm 59.80 84.59 80.27 74.34 25.35 28.50 Nyctiphanes simplex 43.82(92.21) 24.49 (77.72) 23.78 (96.76) 29.73 (94.32) 1.22 (18.96) 0.54 ( 3.47) Nematoscelis difficilis 2.58 ( 5.43) 4.61 (14.63) 0.18 ( 0.73) 0.66 ( 2.09) 0.05 ( 0.81) 0.04 ( 0.24) Stylocheiron affine 0.19 ( 0.40) 0.16 ( 0.50) 0.27 ( 1.10) 0.48 ( 1.54) 0.36 ( 5.59) 0.82 ( 5.24) Stylocheiron longicorne 0.03 ( 0.03) 0.03 ( 0.10) Stylocheiron maximun * ( 0.01) * ( 0.01) Euphausia hemigibba * ( 0.01) Euphausia pacifica 0.50 ( 1.05) 0.99 ( 3.14) * ( 0.01) Euphausia gibboides 0.27 ( 0.57) 0.91 ( 2.90) * ( 0.02) 0.04 ( 0.12) Euphausia recurva 0.01 ( 0.01) 0.01 ( 0.02) Stylocheiron abbreviatum 0.03 ( 0.06) 0.03 ( 0.09) * ( 0.01) Thysanoessa gregaria 0.08 ( 0.17) 0.09 ( 0.28) * ( 0.01) 0.03 ( 0.11) Thysanoessa spinifera 0.16 ( 0.52) * ( 0.01) Nematobrachion flexipes 0.01 ( 0.03) * ( 0.01) 0.02 ( 0.06) 0.01 ( 0.09) Euphausia eximia 0.01 ( 0.02) 0.02 ( 0.07) 0.33 ( 1.35) 0.54 ( 1.73) 4.34 (67.65) 12.58 (80.14) Nematoscelis tenella * ( 0.01) Nematoscelis gracilis * ( 0.01) 0.18 ( 2.85) 0.62 ( 3.92) Euphausia distinguenda 0.05 ( 0.84) 0.26 ( 1.64) Euphausia tenera 0.20 ( 3.14) 0.83 ( 5.27) Euphausia diomedeae 0.01 ( 0.16) Total 47.52 31.52 24.58 31.52 6.41 15.70 TABLE 2. – Average of sea surface temperature (°C), zooplankton biomass (ml 1000-3), and abundance (ind 1000 m-3) of the euphausiids obtained by Bongo net trawls along the west coast of Baja California, México. Relative abundance is shown in parentheses. * = abundance < 0.005 ind 1000 m-3. TABLE 3. – Mean abundance of the scattering layer recorded hydroacoustically by an echosounder, Simrad EY-200, (200 kHz), by latitudi- nal zone. Abundance is expressed as individuals per hectare using a target strength range between - 53 to -57 dB. n = number of echograms analyzed. TABLE 3. – Mean abundance of the scattering layer recorded hydroacoustically by an echosounder, Simrad EY-200, (200 kHz), by latitudi- nal zone. Community structure of the euphausiids The euphausiid community structure, and probably all the zooplank- ton community, showed strong latitudinal changes (Table 1 and 2). Nyctiphanes simplex was about two times more abundant during the day than at night at Ensenada (north) and Bahia Magdalena (south). At Punta Eugenia, this euphausiid had almost the same abundance, day or night. The rest of the species showed their highest abundance at night, suggesting night vertical migration to the surface (Table 2). FIG. 3. – Cluster analysis (1-Pearson r using weighted pair-group average) of the euphausiid species obtained with the Bongo net using samples (59 stations) obtained during the night (2000 to 0500) sorted by sampling stations (regional analysis). These groups were estimated considering a similarity level of about 2.1 (dashed line). Euphausia diomedeae was not included in the analysis because it was caught only during the day. Black points on the y-axis indicate the northern area stations. FIG. 3. – Cluster analysis (1-Pearson r using weighted pair-group average) of the euphausiid species obtained with the Bongo net using samples (59 stations) obtained during the night (2000 to 0500) sorted by sampling stations (regional analysis). These groups were estimated considering a similarity level of about 2.1 (dashed line). Euphausia diomedeae was not included in the analysis because it was caught only during the day. Black points on the y-axis indicate the northern area stations. 84 J. GÓMEZ-GUTIÉRREZ et al. and only zooplankton of 500 µm showed day-night difference, suggesting an active diel vertical migra- tion or net avoidance during daytime. The zooplankton biomass from the 300-µm mesh net trawls showed significant latitudinal changes (three-way ANOVA P < 0.05) but no significant dif- ferences between offshore-inshore regions and day- night (three-way ANOVA P > 0.05), indicating fac- tors, such as patchiness and vertical distribution of the individual species during day and night tend to balance each other out. The zooplankton biomass obtained using the 500-µm mesh net showed signif- icant latitudinal changes and day-night biomass changes (three-way ANOVA P < 0.05). These did not show significant differences among the off- shore-inshore regions (Three-way ANOVA P > 0.05). Thus, two different-size zooplankton had strong latitudinal changes probably related to changes in the zooplankton community structure, At particular SSLs, opening-closing net trawls were made to determine the euphausiid composition species above, within, and below the SSL. Nine euphausiid species were caught using this gear. Nyc- tiphanes simplex (96%) and E. Community structure of the euphausiids White bars are samples obtaining during the day (0600 to 1900) and black bars are samples taken during the night (2000 to 0500). FIG. 5. – Average body weight by size of the three most abundant euphausiid species (Nyctiphanes simplex, Nematoscelis difficilis, and Euphausia eximia), in the three latitudinal regions expressed as body carbon weight (mg C 1000 m-3) calculated from dry-weight equations reported by Gómez-Gutiérrez and Robinson (1997) by assuming a carbon content of 45%. White bars are samples obtaining during the day (0600 to 1900) and black bars are samples taken during the night (2000 to 0500). erentially above 20 m (15 to 17 °C). Whereas, in the southern area, both species were found below the thermocline at about 35 m with a similar range of temperature (15 to 17 °C) (Fig. 4). These patterns are similar to the vertical distribution of the zoo- plankton biomass estimated by the Bongo samples (volume displaced) and the abundance of echoes related to zooplankton shoals (-53 to -57 dB) esti- mated in layers 5-m thick (Fig. 4). individuals observed mainly during the night (<10- mm total length and an integrated biomass of 35-mg C 1000 m-3). Nematoscelis difficilis had an impor- tant standing stock only in the north during the night with an integrated standing stock of 643-mg C 1000 m-3. In the center and southern areas, its biomass was almost negligible with less than 6 mg C 1000 m- 3. Euphausia eximia had an opposite trend showing its highest standing stock in the southern area (186 mg C 1000 m-3) during the day, decreasing north- ward (center area 39 mg C 1000 m-3 and north area < 0.5 mg C 1000 m-3). In terms of carbon, the center area was the least productive of the three in euphausiid biomass partially caused by populations composed of relatively smaller individuals. Each latitudinal region showed a different stand- ing stock of the euphausiids expressed as mg C 1000 m-3 estimated for the three most abundant species (Fig. 5). Nyctiphanes simplex showed its highest biomass in the north with an integrated standing stock (the sum of the biomass of all the classes of sizes) of 393 mg C 1000 m-3, and the center area (76 mg C 1000 m-3) contributed to mainly by juveniles and adults. Relatively similar abundances were recorded during both day and night. Community structure of the euphausiids eximia (3%) (most of them in calyptope and furciliae stages) were the dominant species in most of these samples. The rest of the species contributed only 1% to the total abun- dance (E. tenera, S. affine, E. distinguenda, N. diffi- cilis, N. tenella, N. gracilis, and E. pacifica, in decreasing abundance). In the north and center, a thermocline was not evident, however, the dominant species (N. simplex and E. eximia) were found pref- FIG. 4. – Vertical distribution of zooplankton biomass estimated by Bongo net (bars expressed in percentage, the italic number is the biomass expressed as mL 1000 m-3), zooplankton abundance measured by the echosounder (continuous line; echoes between -53 and -57 dB expressed as ind ha-1), and vertical distribution of two of the most abundant euphausiid species Nyctiphanes simplex and Euphausia eximia in the three latitudinal regions expressed as relative abundance. White bars are day samples and black bars are night samples. The italic numbers are the total abundance integrated over all strata expressed as ind 1000 m-3. In the north and central areas, coastal stations are shown. In the southern area, the offshore stations where the SSL and these species were more abundant are shown. FIG. 4. – Vertical distribution of zooplankton biomass estimated by Bongo net (bars expressed in percentage, the italic number is the biomass expressed as mL 1000 m-3), zooplankton abundance measured by the echosounder (continuous line; echoes between -53 and -57 dB expressed as ind ha-1), and vertical distribution of two of the most abundant euphausiid species Nyctiphanes simplex and Euphausia eximia in the three latitudinal regions expressed as relative abundance. White bars are day samples and black bars are night samples. The italic numbers are the total abundance integrated over all strata expressed as ind 1000 m-3. In the north and central areas, coastal stations are shown. In the southern area, the offshore stations where the SSL and these species were more abundant are shown. LATITUDINAL CHANGES OF EUPHAUSIIDS ASSEMBLAGES 85 DINAL CHANGES OF EUPHAUSIIDS ASSEMBLAGE FIG. 5. – Average body weight by size of the three most abundant euphausiid species (Nyctiphanes simplex, Nematoscelis difficilis, and Euphausia eximia), in the three latitudinal regions expressed as body carbon weight (mg C 1000 m-3) calculated from dry-weight equations reported by Gómez-Gutiérrez and Robinson (1997) by assuming a carbon content of 45%. Community structure of the euphausiids A clear latitudi- nal cline of total length was observed with the larg- er animals in the north and the smaller animals in the south. This latter area had a population of smaller TABLE 4. – Frequency of records of the zooplankton patches per inshore-offshore regions. Average of the variables (length, depth, and elon- gation) of the scattering layer recorded hydroacoustically (200 kHz) by latitudinal zone using all target strength range (-32 to -57 dB). The standard deviation is show in parentheses. Echograms showed that no animal aggregations were neglected. Sound scattering layer characteristics recorded by the echosounder The northern transects had the highest concentra- tions of the SSL over the continental shelf; howev- er, in the south, a tropical assemblage had smaller 86 J. GÓMEZ-GUTIÉRREZ et al. FIG. 6. – Box-and-whisker plot of the abundance (ind ha-1) and percentage of sound scattering layer compactness of zooplankton and nekton (echoes -53 to -57 dB) at 0-50 m over time of the north (Ensenada) (A and B), center (Punta Eugenia) (C and D), and in the south (Bahia Magdalena) (E and F). FIG. 6. – Box-and-whisker plot of the abundance (ind ha-1) and percentage of sound scattering layer compactness of zooplankton and nekton (echoes -53 to -57 dB) at 0-50 m over time of the north (Ensenada) (A and B), center (Punta Eugenia) (C and D), and in the south (Bahia Magdalena) (E and F). shoals offshore. Ensenada (north) accounted for 55%, and Punta Eugenia (center) accounted for 32% of the total echoes recorded. Only about 13% were recorded in the southern area (Bahia Magdalena) (Table 3). Diel zooplankton backscatter showed Ensenada and Punta Eugenia to be the regions with the highest abundance in the 0- to 50-m layers (Fig. 6 a and c). The southern sector (Bahia Magdalena) had very low abundance with its highest abundance occurring during the night (Fig. 6 e). No significant differences were found between day and night backscattering recorded hydroacoustically in the three latitudinal regions (Kruskal-Wallis test; P > 0.001). The daily variation of percentage of com- pactness indicated that in the Ensenada region very concentrated SSLs were found during the night in the 0- to 50-m layer (Fig. 6 b). At Punta Eugenia, the SSLs were very compact during both day and night, particularly between 1100 and 2100 (Fig 6 d). At Bahia Magdalena, we found the lowest percentage of compactness (< 50%) of the SSL. Within the 0- to 50-m depth, the highest compactness was found dur- ing the night. SSL distribution in this region was extremely patchy, resulting in a skewed frequency distribution of density (Fig. 6 f) shoals offshore. Ensenada (north) accounted for 55%, and Punta Eugenia (center) accounted for 32% of the total echoes recorded. Only about 13% were recorded in the southern area (Bahia Magdalena) (Table 3). Diel zooplankton backscatter showed Ensenada and Punta Eugenia to be the regions with the highest abundance in the 0- to 50-m layers (Fig. 6 a and c). Sound scattering layer characteristics recorded by the echosounder The southern sector (Bahia Magdalena) had very low abundance with its highest abundance occurring during the night (Fig. 6 e). No significant differences were found between day and night backscattering recorded hydroacoustically in the three latitudinal regions (Kruskal-Wallis test; P > 0.001). The daily variation of percentage of com- pactness indicated that in the Ensenada region very concentrated SSLs were found during the night in the 0- to 50-m layer (Fig. 6 b). At Punta Eugenia, the The size and shape (elongation = length/depth) of the SSL was obtained from the echogram visual- ization. The size was estimated from each echogram based on the ship’s speed (11 knots) and time spent along the transect. In the northern region (Ensenada- Punta Baja) and the center region (Punta Eugenia- Bahia Asuncion), the zooplankton shoals hydroa- coustically recorded were large and dense (mean sizes were 10- and 7-km long with a mean compact- TABLE 4. – Frequency of records of the zooplankton patches per inshore-offshore regions. Average of the variables (length, depth, and elon- gation) of the scattering layer recorded hydroacoustically (200 kHz) by latitudinal zone using all target strength range (-32 to -57 dB). The standard deviation is show in parentheses. Echograms showed that no animal aggregations were neglected. LATITUDINAL CHANGES OF EUPHAUSIIDS ASSEMBLAGES 87 Zone and transects Time Frequency of positive SSLs Length of the Depth of m Elongation analyzed per region SSL m the SSL Length/Depth Neritic Slope Oceanic North 2 and 3 0800-1400 5 1 4 6663 (4425) 24 (15) 282 North 2 and 3 2200-0700 6 4 5 10100 (4588) 35 (17) 287 44% 20% 36% Center 1 to 4 0800-1900 7 2 3 4084 (3788) 33 (20) 124 Center 1 to 4 2000-0700 13 7 5 7148 (4087) 42 (22) 170 37% 33% 30% South 1 and 2 0800-1900 1 1 6 5139 (2684) 30 (15) 174 South 1 and 2 0000-0500 2 0 4 5012 (2480) 37 (13) 136 21% 7% 72% LATITUDINAL CHANGES OF EUPHAUSIIDS ASSEMBLAGES 87 FIG. 7. – Comparison of three typical scattering layers recorded hydroacoustically in the three latitudinal regions along the west coast of Baja California during the day and night and superimposed over sea temperature profiles. Echograms included all target strength ranges (-32 to - 56 dB). Sound scattering layer characteristics recorded by the echosounder North (transect N3) in day, 1006 (A) and night, 2310 (B); center (transect C4) in day, 0648 (C) and night, 0019 (D), and south (transect S2) in day, 1225 (E) and night, 0010 (F). The x-axis shows the length of the transect expressed as kilometers. FIG. 7. – Comparison of three typical scattering layers recorded hydroacoustically in the three latitudinal regions along the west coast of Baja California during the day and night and superimposed over sea temperature profiles. Echograms included all target strength ranges (-32 to - 56 dB). North (transect N3) in day, 1006 (A) and night, 2310 (B); center (transect C4) in day, 0648 (C) and night, 0019 (D), and south (transect S2) in day, 1225 (E) and night, 0010 (F). The x-axis shows the length of the transect expressed as kilometers. ness of 15% and 19%). The shoals were found to be mainly of the neritic species Nyctiphanes simplex and the temperate species Nematoscelis difficilis, Euphausia pacifica, and Thysanoessa spinifera. In the southern area, in the smaller and dispersed patches (mean size 5-km long and 11% compact- ness), we recorded tropical species, Euphausia eximia, E tenera, and E. distinguenda, which pre- sumably did not form swarms, with N. simplex in lower abundance (data from Bongo nets), found at night (Table 2). mid-water samples) and compactness over the coastal shelf both day and night (Fig. 7 c, d). A high acoustic intensity in the zooplankton-red crab inshore patches suggests this layer is not homoge- neous, probably as a result of the presence of fish schools within the zooplankton patches. In the southern area, the smallest patches were found in the offshore area with lower compactness (Fig. 6 e, f). North to south changes in patch structure was caused by strong latitudinal changes in physical oceanography that affect the species success at each region. Representative echograms (all target-strength ranges included) during the day and night along the three latitudinal zones are shown in Figure 7. Target- strength analysis indicated that pelagic fish were present within the zooplankton layer. The northern zone had long patches over the coastal shelf during the day, increasing in size and density during the night in the inshore and offshore areas (Fig. 7 a, b). In the center area, a dense shoal dominated by the decapod red crab (Pleuroncodes planipes) had extraordinary abundance (evidenced by Isaacs-Kidd DISCUSSION Sound-scattering-layer dynamics and euphausiid community structure obtained via the Isaacs-Kidd and Bongo nets showed a strong latitudinal cline during the autumn. According to Gómez-Gutiérrez and Robinson (1997), the euphausiid abundance and the biomass of macrozooplankton (> 1000 µm) were 88 J. GÓMEZ-GUTIÉRREZ et al. more important in the northern area than in the south during December 1993 along the west coast of Baja California, suggesting a recurrent latitudinal trend found during the second part of the year. Our data showed a 300- and 500-µm zooplankton biomass also had a significant latitudinal cline in its abun- dance and in the carbon content for three of the most abundant euphausiid species. This work tests the hypothesis that euphausiid community structure changes are parallel to morphological characteristics of the scattering layer where they live. The temper- ate euphausiid assemblages inhabit larger and more concentrated SSLs found mainly over the coastal shelf in the northern and central area. In these regions, the neritic euphausiid Nyctiphanes simplex, which frequently forms dense surface swarms, had its highest abundance over the continental shelf in the upper 25 meters (within and above a weak ther- mocline). Hydroacoustic measurements made for each five-meter depth also showed the highest abun- dance near the surface. In the southern region, the dispersed-offshore SSLs were dominated by a trop- ical pelagic assemblage of species like Euphausia eximia, E. distinguenda, and E. tenera. Euphausia eximia demonstrated its highest abundance below a strong thermocline > 30-m deep, and the rest of the zooplankton and nekton (recorded hydroacoustical- ly) remained also in deeper layers. These latitudinal trends are reasonably constant unlike the diel vari- ability observed in the SSLs appearance caused by the 24-h vertical migration reported by Robinson and Gómez-Gutiérrez (1998). Latitudinal changes in N. simplex growth production was reported by Gómez-Gutiérrez et al. (1996), supporting the idea that the southern region is less productive than northern ones, and the SSLs are less dense and smaller along the southern part of Baja California. Estimations of the standing stock expressed as the carbon content of three of the most abundant euphausiid species indicate that the northern area is at least four times more productive than the southern area, showing different productivity between these two environments. Petigas and Levenez (1996) made an echogram acoustic density of the layer decreased with increas- ing thermocline gradients. DISCUSSION Thus, the patchiness of whole zooplankton and nekton was less intense where vertical gradients were strong. This is con- trary to the results of Barange (1994) where a strong degree of physical forcing and cross-shelf activity along a frontal zone affected the intensity of patchi- ness in the Benguela upwelling system. Robinson et al. (1997) reported a similar dispersed offshore SSL in the southern region (Bahia Magdalena) in Decem- ber 1993, dominated by E. eximia, the red crab Pleu- roncodes planipes, and the mesopelagic fish Vin- ciguerria lucetia, indicating that this is a recurrent feature of the SSL dynamics in this southern area during the autumn. more important in the northern area than in the south during December 1993 along the west coast of Baja California, suggesting a recurrent latitudinal trend found during the second part of the year. Our data showed a 300- and 500-µm zooplankton biomass also had a significant latitudinal cline in its abun- dance and in the carbon content for three of the most abundant euphausiid species. This work tests the hypothesis that euphausiid community structure changes are parallel to morphological characteristics of the scattering layer where they live. The temper- ate euphausiid assemblages inhabit larger and more concentrated SSLs found mainly over the coastal shelf in the northern and central area. In these regions, the neritic euphausiid Nyctiphanes simplex, which frequently forms dense surface swarms, had its highest abundance over the continental shelf in the upper 25 meters (within and above a weak ther- mocline). Hydroacoustic measurements made for each five-meter depth also showed the highest abun- dance near the surface. In the southern region, the dispersed-offshore SSLs were dominated by a trop- ical pelagic assemblage of species like Euphausia eximia, E. distinguenda, and E. tenera. Euphausia eximia demonstrated its highest abundance below a strong thermocline > 30-m deep, and the rest of the zooplankton and nekton (recorded hydroacoustical- ly) remained also in deeper layers. These latitudinal trends are reasonably constant unlike the diel vari- ability observed in the SSLs appearance caused by the 24-h vertical migration reported by Robinson and Gómez-Gutiérrez (1998). Latitudinal changes in N. simplex growth production was reported by Gómez-Gutiérrez et al. (1996), supporting the idea that the southern region is less productive than northern ones, and the SSLs are less dense and smaller along the southern part of Baja California. DISCUSSION For example, Barange (1994), using a Sim- rad EK-400 38-kHz echo sounder at the Agulhas bank (South Africa), estimated that zooplankton patches are relatively long (71 m) and thin (5 m), and they are slightly larger than horse-mackerel patches. that other physicochemical variables or behavior can have an important role in the vertical distribu- tion of the SSL. Most euphausiids were caught with different net gear during the night in the 5- to 50-m layer where acoustic records were also more fre- quent. They migrated to deeper layers during the day crossing the thermocline and halocline. This suggests a typical vertical migration to the surface during the night (as found in the north and center areas) with little relation to the physicochemical variables. A relation between the appearance of a SSL and environmental variables alone may not pro- duce any new insight. Our estimations of the zooplankton-nekton shoaling (no patchiness sensu Ritz, 1994) are cur- rently too coarse; however, they are good enough to prove that the SSL morphological variability is a function of the community structure. Schoenherr (1991), although his main goal was to shown a rela- tion between the blue whale (Balaenoptera muscu- lus) and the temperate euphausiid (Thysanoessa spinifera) distribution, describes the deep scattering layer in the Monterey submarine canyon (37°N), reporting that the deep scattering layers were 1- to 2- km wide with the thickest patches concentrated at depths of 130-150 m located near the shelf break. His echograms (echosounder working with a fre- quency of 100-200 kHz) showed a similar SSL-mor- phological appearance similar to the SSL recorded at our north and center area and those reported by Robinson and Gómez-Gutiérrez (1998) near Ense- nada (30°N) during July 1995, where SSLs were dominated by the euphausiids Nyctiphanes simplex and Euphausia pacifica. According to Bongo net samples, Nyctiphanes simplex was found to be about two times more abun- dant during the day than at night at Ensenada (north) and Bahia Magdalena (south), probably because this species tended to form dense surface swarms during the day in environments favorable to reproduction and feeding. In the center area, there was a similar abundance during the day and night. DISCUSSION Dense euphausiid swarms were detected and showed high- ly concentrated swarms near the seabed during the night (Robinson and Gómez-Gutiérrez, 1998) sug- gesting that this species displays very different diel vertical patterns as a function, possibly, of the sea- son and local environmental conditions. Regions that were dominated by omnivorous temperate species like E. pacifica and N. difficilis along with N. simplex (these species have highly setose maxil- lae, nearly equal length periopods, disproportionate- ly large pars molaris on the mandible, and a feeding basket displaying mainly omnivorous feeding habits) were associated with SSLs with the highest values of compactness in the 0- to 50- m layer, sug- gesting that these temperate species form dense swarms (Robinson and Gómez-Gutiérrez, 1998). A tropical assemblage dominated by carnivorous species (the first and second pair of periopods elon- gated to form grasping legs, a small par molaris rel- ative to the incisor, and a coarser setose feeding bas- ket) like E. eximia, E. distinguenda, and E. tenera, was found within a relatively small SSL 4-km). Our findings represent a different SSL dynamic pattern to that described for offshore regions, which were done in regions of water depths of about 1,000 to 4,000 m. In offshore regions, depth distributions, vertical and horizontal dimensions of the aggrega- tions, and gaps between aggregations are relatively consistent (Smith et al., 1989). Our data over the continental shelf suggest a more variable SSL patch- iness dynamic than in the oceanic environment. Hydroacoustical records were, in fact, from all zoo- plankton and nekton assemblages, but we only ana- lyzed the euphausiid component. Therefore part of the echoes recorded could be animals detected with different patchiness behavior and vertical migration than that of the euphausiids. Probably this was the cause of several mismatches in the horizontal distri- bution of the biomass estimated via Bongo nets and Isaacs Kidd midwater nets, and recorded using the echosounder. The primary instrumental shortcomings originate in HADAS’ ability as an echo-counter and the lack of resolution of our echosounder (200 kHz) to record animals smaller than 7 mm, which includes most of the meso- and macrozooplankton communi- ty structure. In addition, because this device uses a single-beam, it was not possible to estimate the sin- gle target strength. Nevertheless, with new methods like dual-beam or split-beam for acoustical process- The Spearman rank correlation between abun- dance of zooplankton recorded by the echosounder vs. DISCUSSION Estimations of the standing stock expressed as the carbon content of three of the most abundant euphausiid species indicate that the northern area is at least four times more productive than the southern area, showing different productivity between these two environments. Gómez-Gutiérrez (1995) demonstrated that N. simplex and E. eximia have different inshore-off- shore life maintenance strategies showing their core distribution to be inshore (N. simplex) and offshore (E. eximia). Hydroacoustic results obtained in the present work suggest that other zooplanktonic and nektonic species have similar inshore-offshore dis- tribution preferences. The shape and patchiness properties of zooplankton can vary widely in differ- ent community structures, and as a result, the acoustic scattering properties vary accordingly. Sig- nificant inshore-offshore differences were found in the community structure and abundance estimated by Bongo net samples and hydroacoustic measure- ments along the peninsula, suggesting behavioral maintenance strategies of some dominant zooplank- ton and nekton species. The vertical migratory behavior of several zooplankton species (i.e. the euphausiids E. pacifica and N. simplex, clupeidae fish larvae, and other neritic species) may help them avoid offshore flow on the surface like other zoo- plankton species in areas dominated by coastal upwelling and complex advective processes in the California Current System. Using conventional nets, Wiebe (1970) provided one of the first direct estimates of zooplankton patch size, estimating a median patch length of between 23 and 27 m during daylight and between 66 and 110 m during the night and concluded that aggrega- tions were physically induced. Previous studies using sophisticated hydroacoustic devices (307-kHz acoustic Doppler current profiler ADCP and a Sim- rad EK-500 split-beam echosounder 120 kHz) reported wide gaps between zooplankton patches (Smith et al., 1989) suggest that the capacity and frequency of the echosounder used are critical to an adequate interpretation of the patch formation Petigas and Levenez (1996) made an echogram coding of fish schools according to the morphology of the echo traces, describing nine types. In this study, because we are describing whole SSLs with multispecies clusters instead of monospecies fish schools, we were unable to do a detailed description of these structures. However, we were able to dis- cern the difference in the SSL in a temperate and a tropical assemblage. Horizontal length and relative LATITUDINAL CHANGES OF EUPHAUSIIDS ASSEMBLAGES 89 process. ACKNOWLEDGEMENTS Isaacs, J.D. and R.A. Schwartzlose. – 1965. Migrant sound scatters: interaction with the sea floor. Science. 150: 1810-1813. Thanks are extended to the students from the Laboratory of Fisheries Ecology UNAM, to the RV ‘El Puma’ crew for assistance and comradeship at sea, and to Dr. Ellis Glazier, CIBNOR, for his edito- rial help with the English text. We thank Dr. Torfinn Lindem for comments and advice about the abilities of HADAS software. This research was supported by funds provided by the Dirección de Estudios de Posgrado e Investigación (DEPI 966584, 970123, and 988002) and by the Consejo Nacional de Cien- cia y Tecnología (CONACyT 940511, N511- N9108). The authors J.G.-G., C.J.R., and V.A.-F. are supported by Sistema Nacional de Investigadores (SNI), and the first author also is supported by a Comisión de Operación y Fomento Actividades Acádemicas del Instituto Politécnico Nacional (COFAA) fellowship. Lindem, T. and H.A. Houri. – 1988. Hydro Acoustic Data Acquisi- tion System HADAS. Department of Physics, University of Oslo, P. Box 0316. Oslo Norway, 4 pp. y pp MacLennan,D.N. and E.J., Simmonds. – 1992. Fisheries Acoustics. Chapman & Hall, Fish and Fisheries Series, London. Massé, J., C. Koutsikopoulos and W. Patty. – 1996. The structure and spatial distribution of pelagic fish schools in multispecies clusters: an acoustic study. ICES J. Mar. Sci., 53: 155-160. clusters: an acoustic study. ICES J. Mar. Sci., 53: 155- y Misund, O.V. – 1993. Dynamics of moving masses: variability in packing density, shape, and size among herring, sprat, and saithe schools. ICES J. Mar. Sci., 50: 145-160. Misund, O.V., A. Anglen and E. Frfnaes. – 1995. Mapping the shape, size, and density of fish schools by echo integration and a high-resolution sonar. ICES J. Mar. Sci., 52: 11-20. g Parsons,T.R., Y. Maita, and C.M. Lalli. – 1984. A manual of chem- ical and biological methods for sea water analysis. Pergamon Press, Oxford. Petigas, P. and J.J. Levenez. – 1996. Spatial organization of pelag- ic fish: echogram structure, spatio-temporal condition, and bio- mass in Senegalense waters. ICES J. Mar. Sci., 53: 147-153. i A 1994 S i l i i l i i b Ad Ritz, D.A. – 1994. Social aggregation in pelagic invertebrates. Adv. Mar. Biol. 30: 155-216. Robinson C.J. and J. Gómez-Gutiérrez. – 1998. Daily vertical migration of dense scattering layers related to shelf-break area in the northwest coast of Baja California, México. J. Plankt. Res., 20(9): 1679-1697. DISCUSSION temperature and salinity obtained via the CTD in the column water showed, in general, no significant correlation, P > 0.001; rs = -0.6190 (north), rs = - 0.7714 (center), and rs = -0.800 (south), suggesting 90 J. GÓMEZ-GUTIÉRREZ et al. Craig, R.E. and S.T., Forbes. – 1969. A sonar for fishing counting. FiskDir. Skr., Ser. Havunders., 15: 210-219. es at work in the ocean’s interior, ecologists can begin to gain insights into the processes associated with zooplankton and nekton patch dynamics. These types of studies should be made in different seasons to test our hypothesis concerning the importance of community structure on SSL dynamics and the probable homogeneity of SSL dynamics during spring-early summer in the southern portion of the California Current System. Gómez-Gutiérrez, J. – 1995. Distribution patterns, abundance and population dynamics of the euphausiids Nyctiphanes simplex and Euphausia eximia in the west coast of Baja California, México. Mar. Ecol. Prog. Ser., 119: 63-76. g Gómez-Gutiérrez, J. and C.J. Robinson. – 1997. Circadian biomass and abundance changes of five euphausiids along the west coast of Baja California Mexico, December 1993. Sci. Mar., 61: 27- 35. Gómez-Gutiérrez, J., R. Palomares-García and D. Gendron. – 1995. Community structure of the euphausiids populations along the west coast of Baja California, México during the weak ENSO 1986-87. Mar. Ecol. Prog. Ser., 120: 41-51. Gómez-Gutiérrez, J., De Silva-Dávila, R, Lavaniegos, E.B. – 1996. Growth production of the euphausiid Nyctiphanes simplex at the coastal shelf off Magdalena Bay, Baja California Sur, Méx- ico. Mar. Ecol. Progr. Ser. ,138: 309-314. ACKNOWLEDGEMENTS ( ) Robinson, C.M., J. Gómez-Gutiérrez and F.V. Arenas - 1997. On the structure of a scattering layer in the southwest coast of Baja California using net trawl samples and hydroacoustic. Cienc. Mar. Baja Calif. Méx., 23(1): 141-154. REFERENCES g p Mar. Baja Calif. Méx., 23(1): 141-154. Smith, P.E., M.D. Ohman and L.E. Eber. – 1989. Analysis of the patterns of distribution of zooplankton aggregations from an acoustic Doppler current profiler. Calif. Coop. Ocean. Fish. Invest. Rep., 30: 88-103. Barange, M. – 1994. Acoustic identification, classification and structure of biological patchiness on the edge of the Agulhas bank and its relation to frontal features. S. Afr. J. mar. Sci., 14: 333-347. p Schoenherr, J.R. – 1991. Blue whales feeding on high concentra- tions of euphausiids around Monterey submarine canyon. Can. J. Zool., 69: 583-594. Brinton, E. – 1962. Variable factors affecting the apparent range and estimated concentration of euphausiids in the North Pacif- ic. Pac. Sci., 16: 374-408. Wiebe, P.H. – 1970. Small scale spatial distribution in oceanic zoo- plankton. Limnol. Oceanogr., 15: 205-217. Brinton, E. – 1979. Parameters relating to the distribution of plank- tonic organisms, especially euphausiids in the Eastern Tropical Pacific. Prog. Oceanogr., 8: 125-189. Scient. ed.: M. Alcaraz
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Qeios · Definition, February 2, 2020 Open Peer Review on Qeios Open Peer Review on Qeios Specify IDH Family Mutation National Cancer Institute National Cancer Institute Qeios ID: 06O0XB · https://doi.org/10.32388/06O0XB Source National Cancer Institute. Specify IDH Family Mutation. NCI Thesaurus. Code C160578. National Cancer Institute. Specify IDH Family Mutation. NCI Thesaurus. Code C160578. A request to enter the specific IDH family mutations that were identified in the study. Qeios ID: 06O0XB · https://doi.org/10.32388/06O0XB 1/1
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A modular computational framework for automated peak extraction from ion mobility spectra
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METHODOLOGY ARTICLE Open Access *Correspondence: Sven.Rahmann@uni-due.de †Equal contributors 1Collaborative Research Center SFB 876, TU Dortmund University, Dortmund, Germany 3Genome Informatics, Institute of Human Genetics, Faculty of Medicine, University of Duisburg-Essen, Essen, Germany Full list of author information is available at the end of the article © 2014 D’Addario et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. D’Addario et al. BMC Bioinformatics 2014, 15:25 http://www.biomedcentral.com/1471-2105/15/25 D’Addario et al. BMC Bioinformatics 2014, 15:25 http://www.biomedcentral.com/1471-2105/15/25 A modular computational framework for automated peak extraction from ion mobility spectra arianna D’Addario1†, Dominik Kopczynski1†, Jörg Ingo Baumbach2 and Sven Rahmann1,3* Background consider Koczulla et al. [1] and Armenta et al. [2]. The analytes, metabolites present within exhaled breath, are pre-separated using the MCC, analogously to gas chro- matography (GC) before mass spectrometry (MS). While ion mobility (IM) spectrometry (IMS) is an estab- lished technology to detect volatile organic compounds (VOCs) in the air or exhaled breath, the more recent combination with multi-capillary columns (MCCs) has opened new applications in biotechnology and medicine, VOCs from the human metabolism in exhaled breath may hint at certain diseases. Applications to diagnosis of lung cancer, chronic obstructive pulmonary disease (COPD) or sarcoidosis have already been reported [3-7]. *Correspondence: Sven.Rahmann@uni-due.de †Equal contributors 1Collaborative Research Center SFB 876, TU Dortmund University, Dortmund, Germany 3Genome Informatics, Institute of Human Genetics, Faculty of Medicine, University of Duisburg-Essen, Essen, Germany Full list of author information is available at the end of the article Abstract Background: An ion mobility (IM) spectrometer coupled with a multi-capillary column (MCC) measures volatile organic compounds (VOCs) in the air or in exhaled breath. This technique is utilized in several biotechnological and medical applications. Each peak in an MCC/IM measurement represents a certain compound, which may be known or unknown. For clustering and classification of measurements, the raw data matrix must be reduced to a set of peaks. Each peak is described by its coordinates (retention time in the MCC and reduced inverse ion mobility) and shape (signal intensity, further shape parameters). This fundamental step is referred to as peak extraction. It is the basis for identifying discriminating peaks, and hence putative biomarkers, between two classes of measurements, such as a healthy control group and a group of patients with a confirmed disease. Current state-of-the-art peak extraction methods require human interaction, such as hand-picking approximate peak locations, assisted by a visualization of the data matrix. In a high-throughput context, however, it is preferable to have robust methods for fully automated peak extraction. Results: We introduce PEAX, a modular framework for automated peak extraction. The framework consists of several steps in a pipeline architecture. Each step performs a specific sub-task and can be instantiated by different methods implemented as modules. We provide open-source software for the framework and several modules for each step. Additionally, an interface that allows easy extension by a new module is provided. Combining the modules in all reasonable ways leads to a large number of peak extraction methods. We evaluate all combinations using intrinsic error measures and by comparing the resulting peak sets with an expert-picked one. Conclusions: Our software PEAX is able to automatically extract peaks from MCC/IM measurements within a few seconds. The automatically obtained results keep up with the results provided by current state-of-the-art peak extraction methods. This opens a high-throughput context for the MCC/IM application field. Our software is available at http://www.rahmannlab.de/research/ims. Keywords: Ion mobility spectrometry, Peak detection, Signal processing, Automated pipeline © 2014 D’Addario et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. D’Addario et al. BMC Bioinformatics 2014, 15:25 http://www.biomedcentral.com/1471-2105/15/25 D’Addario et al. BMC Bioinformatics 2014, 15:25 http://www.biomedcentral.com/1471-2105/15/25 D’Addario et al. BMC Bioinformatics 2014, 15:25 http://www.biomedcentral.com/1471-2105/15/25 For a sample pre-separated by an MCC, an IM spectrum is captured periodically at several different retention times, e.g. each 100 ms for up to 10 minutes. The retention time r is the time a compound needs to pass the MCC. are its coordinates (r, t) and signal intensity s (for exam- ple s = Sr,t). Additional parameters may describe the peak shape or alternative signal values. For typical anal- ysis algorithms, a triple (r, t, s) suffices, where we use s as shorthand for any signal at or around (r, t), how ever computed. The drift time t′ is the time a compound needs to drift through the IM spectrometer and is influenced by param- eters such as drift tube length, intensity of electric field as well as temperature or ambient pressure. Figure 1 illus- trates a schematic cross section of an IM spectrometer. It is thus advantageous to consider a normalized quan- tity: the reduced inverse mobility t in Vs/cm2. Each IM spectrum (at a specific MCC retention time r) provides a signal intensity (ion count, measured as voltage change on a Faraday plate; for technical details see [8]) for each value of t. The position and intensity of peaks indicates the pres- ence and concentration of certain VOCs. Peaks behaving differentially (presence vs. absence or quantitative differ- ence) in two classes of measurements (i.e., patients vs. controls) may represent potential biomarkers that can hint at specific diseases. The need for automated peak extraction: our contributions The fundamental step of peak extraction from a raw IMSC is the basis for all subsequent data mining classifi- cation steps [9]. Given a set of measurements, a domain expert assisted by visualization software (such as Visual- Now from B&S Analytik, Dortmund, Germany) is able to interactively pinpoint peak locations within a few minutes. An experienced expert can often distinguish weak signals from noise. We obtain a two-dimensional IM spectrum-chroma- togram (IMSC) S: R × T →Z with retention times r ∈R, inverse mobilities t ∈T, and signal intensities S(r, t) ∈Z (measured as unsigned 12-bit values). In prac- tice, we have equidistant points on both retention time and inverse mobility axes; therefore we may assume that R = {1, . . . , m} and T = {1, . . . MCC/IM measurements and peaks A single measurement with an IM spectrometer takes about 100 ms, using nitrogen or synthetic air as drift gas. Page 2 of 12 Page 2 of 12 D’Addario et al. BMC Bioinformatics 2014, 15:25 http://www.biomedcentral.com/1471-2105/15/25 , n}, where these index values correspond to actual times and reduced inverse mobilities. MCC/IMS technology has matured to a point where it is applied to automated monitoring [10] and moves towards a high-throughput domain. Here, interactive expert-driven and computer-assisted peak extraction is no longer possible. To a lesser extent, the same situ- ation holds true in exploratory medical studies, where the amount of available measurements increases beyond human analysis capabilities. Therefore, automated peak extraction methods are urgently required. As another advantage, they offer better reproducibility and increased speed. However, they may make certain assumptions about the data and lack in adaptability. We call a single row or spectrum Sr at a retention time r an IM spectrum. A single column S·,t at a certain t is called IM chromatogram. The whole matrix S is the IMSC. Regions of S with a high signal intensity are called peaks. An IMSC can be visualized as a heat map (Figure 2). In every IMSC, the reactant ion peak (RIP) produced by the ionisation of the drift gas is visible as a high-intensity chromatogram at a reduced inverse mobility of approx- imately t = 0.48 Vs/cm2. When additional analyte ions occur, the RIP is reduced and may even disappear if the analyte concentrations are extremely high. We describe each peak with a set of (at least three) descriptors, which We here provide a modular automated peak extrac- tion framework. The task of peak extraction is divided Figure 1 Schematic cross section of an IM spectrometer. Analyte compounds pre-separated by the MCC are ionized in the ionization chamber. The ions are accelerated by an electric field and move through the drift tube. They cause a voltage change when colliding with the Faraday plate; this is the measured signal. Figure 1 Schematic cross section of an IM spectrometer. Analyte compounds pre-separated by the MCC are ionized in the ionization chamber. The ions are accelerated by an electric field and move through the drift tube. They cause a voltage change when colliding with the Faraday plate; this is the measured signal. D’Addario et al. BMC Bioinformatics 2014, 15:25 http://www.biomedcentral.com/1471-2105/15/25 Page 3 of 12 Page 3 of 12 Figure 2 IMSC visualized before and after preprocessing. Top: Heat map of a raw IMSC. D’Addario et al. BMC Bioinformatics 2014, 15:25 http://www.biomedcentral.com/1471-2105/15/25 X-axis: reduced inverse mobility t in Vs/cm2; Y-axis: retention time r in seconds; signal: white (lowest) < blue < purple < red < yellow (highest), reactant ion peak (RIP) at t=0.48 Vs/cm2. Bottom: IMSC after preprocessing using bc-dn-s (see text). The peak extraction process is divided into four steps (Figure 3). Each step can be implemented by differ- ent modules represented by the yellow boxes containing an abbreviation for each module name. Each resulting pipeline requires a single IMSC as input and outputs a list of peaks. Each peak is represented at least by the following information: name of the measurement, an automatically given peak ID, reduced inverse mobility, retention time, signal value, reduced inverse mobility index and reten- tion time index. Knowing the name of measurement for each peak is convenient when comparing several peak lists from different measurements. We now discuss the four distinct steps. Preprocessing transforms a (raw) IMSC into another (processed) IMSC, i.e., no data reduction or peak extrac- tion takes place. Raw IMSCs are noisy and include the confounding RIP. To remove both noise and the RIP, we describe three modules: Baseline Correction (bc), De-Noising (dn) and Smoothing (s); every module’s input and output is an IMSC. Baseline Correction (bc) han- dles the RIP (and the baseline in general), removes it, and uncovers underlying peaks. De-Noising (dn) estimates the probability of a data point belonging to noise in order to remove the noise. Smoothing (s) applies a smoothing filter. The order of execution is commutable, but none of these modules can be omitted. Figure 2 shows a measurement before and after preprocessing. Figure 2 IMSC visualized before and after preprocessing. Top: Heat map of a raw IMSC. X-axis: reduced inverse mobility t in Vs/cm2; Y-axis: retention time r in seconds; signal: white (lowest) < blue < purple < red < yellow (highest), reactant ion peak (RIP) at t=0.48 Vs/cm2. Bottom: IMSC after preprocessing using bc-dn-s (see text). Figure 2 IMSC visualized before and after preprocessing. Top: Heat map of a raw IMSC. X-axis: reduced inverse mobility t in Vs/cm2; Y-axis: retention time r in seconds; signal: white (lowest) < blue < purple < red < yellow (highest), reactant ion peak (RIP) at t=0.48 Vs/cm2. Bottom: IMSC after preprocessing using bc-dn-s (see text). ure 2 IMSC visualized before and after preprocessing. Top: e 2 IMSC visualized before and after preprocessing. D’Addario et al. BMC Bioinformatics 2014, 15:25 http://www.biomedcentral.com/1471-2105/15/25 Top: Peak candidate detection finds a list of potential peaks within the preprocessed IMSC. We implemented two alternative modules called Local Maxima (lm) and Cross Finding (cf). The input of either module is a processed IMSC, and the output is a list of candidate peaks, which is further refined in the next step. Local Maxima finds local maxima within the two-dimensional IMSC, while Cross Finding searches for zeros in the first partial derivatives with respect to both retention time and reduced inverse mobility. into four steps that are performed in sequence. Each step allows us to use different specific methods, implemented as separate modules. Each (reasonable) combination of modules, together with individual module parameters, specifies a concrete peak extraction pipeline and trans- forms an IMSC into a list of peaks. In Section ‘Methods’ we introduce the peak extraction framework, enumerating briefly all pipeline steps. The next three sections (Sections ‘Modules for preprocessing, Modules for peak candidate detection, Modules for peak picking, A module for peak modeling (pme)’) explain the available modules for each step in detail. Information on the software architecture and implementation is given in Section ‘Architecture and implementation’. Results on a complete dataset are provided in Section ‘Results’, where we compare the different combinations with each other and to manual peak extraction. Section ‘Discussion and conclusion’ concludes. Peak picking examines the proposed candidates and generates the final list of extracted peaks. We have so far implemented three modules. All three methods cal- culate a representative peak for a set of peaks whose positions are too close to be considered distinct. Merging by signal intensity (ms) is a basic method considering the distance between two candidates; it picks highest signal peak from a set of close peaks within a surrounding box of given size. Cluster editing (ce) discovers peak clusters by solving the cluster editing problem and returns the peak with highest intensity of each cluster as representative. EM Clustering (emc) works similarly, but discovers peak clusters using the EM algorithm. Methods Peak modeling is an optional final step that can be used to estimate additional peak parameters, describing the shape and position more precisely. A module called Peak model estimation (pme) has been implemented. In Baseline correction (bc) Intuitively and informally, a baseline spectrum B = (Bt)t∈T is defined such that Bt is a typical or insignificantly high value at reduced inverse mobility t when consider- ing the whole measurement. Formally, for each reduced inverse mobility t, we consider a histogram Ht with bin size 1 of the chromatogram S·,t, i.e., Ht,i is the number of data points with intensity i in the chromatogram. Bader [13] presented a method that assumes a log-normal model as baseline and estimate its parameters before subtracting from spectrum. We developed a new method since Baders method does not erase the whole RIP. In a typical chro- matogram (mostly noise, one or a few peak(s), no RIP), most intensities are at noise level, so the most prominent peak in the histogram indicates that level. In a RIP chro- matogram, the most prominent peak corresponds to the RIP level (Figure 4). In both cases and in the intermedi- ate ones as well, we model the most prominent peak of the histogram by a Gaussian distribution and the remainder by the uniform distribution between lowest and highest observed intensity. Framework overview We present a framework for automatic processing of an MCC/IM measurement (ion mobility spectrum-chroma- togram, IMSC) to discover and quantify all present peaks. D’Addario et al. BMC Bioinformatics 2014, 15:25 http://www.biomedcentral.com/1471-2105/15/25 Page 4 of 12 Figure 3 Steps and modules of the peak extraction framework PEAX. Figure 3 Steps and modules of the peak extraction framework PEAX. time-critical applications this step is generally omitted by using the “empty module” ε. to our previous work on peak modeling (contained herein as the module Peak Model Estimation (pme)), where we describe how to apply the EM algorithm to a mixture of Inverse Gaussian distributions to infer peak shape parameters [12]. The Peak Modeling step can be exchanged with the Peak Picking step, meaning that each candidate peak is modeled, and picking is done on the modeled candidate peaks. In the following section we discuss all modules in detail and introduce several parameters, remark that user adjustable parameters are emphasized. Mixture models and expectation maximization Several of our modules use mixture modeling, i.e., the data is viewed as a realization of a mixture distribution f (x | θ) = C  c=1 ωc fc(x | θc), f (x | θ) = C  c=1 ωc fc(x | θc), where c indexes the C different components, θc denotes all parameters of distribution fc, and θ = (θ1, . . . , θc) is the collection of all parameters. We allow that the dis- tributions fc are of different types, e.g., a uniform and a Gaussian one. The mixture coefficients ωc satisfy ωc ≥0 for all c, and  c ωc = 1. c The goal of mixture model analysis is to estimate the mixture coefficients ω = (ωc) and the individual model parameters θc (whose number and interpretation depends on the parametric distribution fc). Since this maximum likelihood problem is non-convex, iterative locally optimizing methods such as the Expectation Max- imization (EM) algorithm [11] are frequently used. The EM algorithm consists of two repeated steps: The E-step (expectation) estimates the expected membership of each data point x in each component and then ω, given the current model parameters θ. The M-step (maximization) estimates maximum likelihood parameters θc for each parametric component fc individually, using the expected memberships as hidden variables that decouple the model. As the EM algorithm converges towards a local optimum of the likelihood function, it is crucial to choose reasonable starting parameters for θ. For details, we refer Thus, we describe the histogram Ht by a heterogeneous two-component mixture model (Gaussian plus uniform) and estimate its parameters (μ, σ 2 for the Gaussian, ωG for the Gaussian mixture coefficient) by the EM algo- rithm, as outlined above. To start the EM iteration, we set μ to the location of the maximum of Ht and σ 2 := 1, while ωG is immediately estimated in the E-step. After convergence, having estimated μ and σ, we say that all intensities up to μ + 2σ belong to the baseline and adjust the chromatogram as follows: S′ r,t := max{Sr,t −(μ + 2σ), 0} for all r ∈R. After repeating this step for every t D’Addario et al. BMC Bioinformatics 2014, 15:25 http://www.biomedcentral.com/1471-2105/15/25 Page 5 of 12 Figure 4 Histograms (y-axis: frequency) of signal intensities (x-axis) of two chromatograms, a typical one (top) and a RIP chromatogram (bottom). Modules for peak candidate detection We discuss two modules to find peak candidates. Both use parameter I (intensity_threshold) as signal intensity threshold. The method is not applied to S directly, but to the locally averaged Ar,t := 1 (2ρ + 1)2 · r+ρ  r′=r−ρ t+ρ  t′=t−ρ Sr′,t′, Ar,t := 1 (2ρ + 1)2 · r+ρ  r′=r−ρ t+ρ  t′=t−ρ Sr′,t′, Smoothing (s) The smoothing module consists of two consecutive meth- ods. The first method is a lowpass filter. The IMSC is transformed from the time/signal domain into the fre- quency/signal domain by a two-dimensional fast Fourier transform (2DFFT). All frequencies above a given fre- quency threshold (parameter fftcutoff) are removed, i.e., set to zero intensity. The inverse transformation of the filtered matrix is done using the inverse two-dimensional fast Fourier transform (I2DFFT). Figure 4 Histograms (y-axis: frequency) of signal intensities (x-axis) of two chromatograms, a typical one (top) and a RIP chromatogram (bottom). The prominent intensity peak is modeled by a Gaussian distribution. with individually estimated μ(t), σ(t), the baseline Bt = μ(t) + 2σ(t) has been removed. The result is smoothed by a Savitzky-Golay filter (SGF) [14] on local windows using smoothing_radius ρ = 4 (i.e., 9 × 9 data points) around each data point. To handle the boundaries of the measurement, we expand the data matrix with a margin containing only zero values. Since the data at the boundary of the measurement does not contain important data, this procedure is uncritical. The SGF computes a weighted average across the window. Mixture models and expectation maximization The prominent intensity peak is modeled by a Gaussian distribution. points with a maximum reduced inverse mobility of t = 1.45 Vs/cm2. With respect to tolerance t := 0.003 Vs/cm2 (value explained in Section ‘Modules for peak picking’) we obtain a tolerance of (2500 · 0.003)/1.45 ≈5 index units. We chose ρ = 4 to avoid taking noise into consideration for smoothing. Considering a histogram of all A-values also with bin size 1 (see Additional file 1: Supplement E), we iden- tify three components: the noise component (the one of interest and to be removed) is modeled as a Gaussian dis- tribution, the signal component (to be kept) is modeled as an Inverse Gaussian distribution and a background com- ponent (that explains every intensity not well explained by the other components) is modeled as a uniform distri- bution over all measured intensities. This yields a three- component heterogeneous mixture model (Gaussian plus Inverse Gaussian plus uniform), whose parameters are again estimated by the EM algorithm. After convergence and a final E-step, we obtain the expected membership values Wr,t (which are a weighted normalized values of every probability computed by the probability models) of each data point (r, t) in the noise component. We adjust the original IMSC such that only the non-noise fraction remains, i.e., S′ r,t := Sr,t · (1 −Wr,t) for all r ∈R, t ∈T. De-noising (dn) The goal of de-noising is to subtract a substantial amount of noise from the IMSC S(r, t) by estimating whether the intensity S(r, t) at coordinates (r, t) belongs to a peak region or can be explained by background noise. In previous work on de-noising Bader [13] uses a wavelet transform but applies it only spectrum wise. Our novel approach is similar to the Baseline Correction (bc) module in the sense that the EM algorithm is used, but the model is more complex and the subtraction works differently. Cross finding (cf) -1 0 1 2 3 4 5 0 2 4 6 8 10 The basic idea of Cross Finding is to find maxima based on the ideas by Fong et al. [15]. To avoid overlooking peaks at the borders, the matrix’s borders are temporarily padded by zeros. We construct two auxiliary matrices DR and DT, both with the same dimensions |R|×|T|. In DT, discrete deriva- tives of spectra are stored (partial derivatives with respect to reduced inverse mobility), DT r,t := Sr,t+1 −Sr,t; analo- gously derivatives of chromatograms are stored in DR. We describe how DT is analysed. 10 In each derived spectrum (for fixed retention time r), we mark downward zero crossings; these are indices t with DT r,t−1 ≥0 and DT r,t < 0. The resulting indices t are called active positions for retention time r. Figure 5 Cross finding: Active positions (marking potential peak maxima) are initially unaligned (top) and then connected by alignment across spectra (bottom; shown as red + and blue x). The same procedure is repeated over all chromatograms giving horizontal bands instead of vertical bands. Intersecting the results from both dimensions results in peak candidates. While we scan through the spectra, we maintain two data structures. The first one is an active set containing lists of active positions connected across several spectra. The second one is a finalized set, where lists from the active sets are moved when they have been processed. Initially both sets are empty. (2) If A+[j] is aligned to some A[i], the corresponding list containing A[i] is already in the active set and extended by A+[j]. (2) If A+[j] is aligned to some A[i], the corresponding list containing A[i] is already in the active set and extended by A+[j]. We want to connect active positions between consecu- tive retention times, i.e., we want to find active positions for spectrum r + 1 corresponding to active positions in spectrum r (see Figure 5(left)). To find the correspon- dences, we use a variant of global alignment between the two sorted integer lists A and A+ containing the active positions. The score of aligning A[i] to A+[j] depends on the distance between A[i] and A+[j]. We use the follow- ing score function: score(i, j) := (1+|A[i] −A+[j] |)−1 ∈ [0, 1]. To prevent that two positions with a high distance are aligned, we introduce a gap score γ = 0.1. Cross finding (cf) As we will thus never align positions A[i] and A+[j] with distance larger than 9 index units, we can solve the alignment problem very efficiently by only considering (i, j) with |A[i] −A+[j] | ≤9. (3) Each A[i] that is not aligned to any A+[j] finalizes its corresponding active list, and the list is moved into the finalized set. After processing all spectra and finalizing each remain- ing list, we obtain several position lists pointing out consecutive maxima throughout each spectrum; see Figure 5(right). The same procedure is analogously performed with matrix DR. We report the intersection of positions found from both matrices (which can be visualised as crosses; hence the name “Cross Finding”). If more than one posi- tion overlap is found between two lists, the position with the highest signal is reported. Each reported point whose signal exceeds I is a candidate for a peak location. Three scenarios are possible between the aligned position pairs: Local maxima (lm) This module reports a peak candidate for every local intensity maximum with intensity at least I in a surrounding area. To report a point (r, t), we require (1.) where ρ is the smoothing_radius parameter. The spectra in our measurements consist of 2500 data where ρ is the smoothing_radius parameter. The spectra in our measurements consist of 2500 data D’Addario et al. BMC Bioinformatics 2014, 15:25 http://www.biomedcentral.com/1471-2105/15/25 Page 6 of 12 -1 0 1 2 3 4 5 0 2 4 6 8 10 -1 0 1 2 3 4 5 0 2 4 6 8 10 Figure 5 Cross finding: Active positions (marking potential peak maxima) are initially unaligned (top) and then connected by alignment across spectra (bottom; shown as red + and blue x). The same procedure is repeated over all chromatograms giving horizontal bands instead of vertical bands. Intersecting the results from both dimensions results in peak candidates. that (r, t) is a local maximum in the sense the each of its eight direct neighbors has a lower or equal signal inten- sity than Sr,t but of at least I, and (2.) that the contiguous area around (r, t) with signal intensity at least I is of suf- ficient size. In other words, we discard points where the surrounding high-intensity area size consists of too few points. The required number of points is controlled by a parameter A ≥9 (area_size). (By the first condi- tion, (r, t) and its eight neighbors always account for nine points; the parameter A can be used to impose stricter conditions.) -1 0 1 2 3 4 5 0 2 4 6 8 10 Modules for peak picking (1) If A+[j] is not aligned to any A[i], it is a “new” active position, and a new list, containing only A+[j] is inserted into the active set. The previous step, peak candidate detection, consid- ers each potential peak location separately. Two peak D’Addario et al. BMC Bioinformatics 2014, 15:25 http://www.biomedcentral.com/1471-2105/15/25 D’Addario et al. BMC Bioinformatics 2014, 15:25 http://www.biomedcentral.com/1471-2105/15/25 Page 7 of 12 w(u, v) := 2b(1−d2(u,v)) −1 if d2(u, v) ≤1, 1 −d2(u, v) otherwise. w(u, v) := 2b(1−d2(u,v)) −1 if d2(u, v) ≤1, 1 −d2(u, v) otherwise. candidates may be called close to each other, e.g., by detecting two local maxima of the same underlying peak that arise because of noise in the data. The range for w(u, v) is therefore [−∞, 2b −1]. If the distance between the two candidates u and v is zero, then the edge (u, v) has the maximum weight 2b −1. If the t- and r-distances of u and v are equal to t and r, respectively, then d2(u, v) = 1 and w(u, v) = 0. For larger distances, the weights are negative. Parameter b called ce_weight_exponent can be set by the user. Thus, not every peak candidate corresponds to a VOC from the breath sample, and the purpose of peak picking is to thin out the candidate list. Bödeker [16] introduced a minimum distance in reten- tion time and in reduced inverse mobility such that two peaks exceeding those distances belong to distinct compounds. We write t for the necessary distance in reduced inverse mobility and r for that in retention time. We use a constant t := 0.003 Vs/cm2 (tol_rim) for the reduced inverse mobility. In retention time we use an affine-linear r := p · r + c for a peak at posi- tion (r, t), where c := 3 s (tol_rt) and p := 0.1 (tol_percent_rt), as suggested by Hauschild et al. [9]. We now describe three modules for peak picking. The weighted cluster editing problem is solved with the yoshiko 2.0 software (http://www.cwi.nl/research/planet- lisa). Merging by signal intensity (ms) Each component is a two-dimensional Gaussian distri- bution with independent dimensions, i.e., diagonal covari- ance matrix. Initially, the mean of every component is the (r, t) location of the corresponding peak candidate. The standard deviation on the r- and t-axis is set to r/3 and t/3, respectively, since 6σ covers most of a Gaussian bell curve. In the E-step, the hidden membership coefficients of each peak to each component are estimated. When a peak candidate is close to another one, the probability that the first model also (partially) describes the second candi- date is comparatively high. In the maximization phase, the parameters of each component are re-estimated based on candidate membership using maximum likelihood esti- mators. In the case of two close candidates, the mean of both components moves towards their middle. When the distance between the means of two components drops below a given threshold, the components are merged: The component of the candidate with lower signal is removed, and its weight is added to the remaining model. The E- and M-steps are repeated until convergence. We sort the n peak candidates by descending signal inten- sity into a list [(ri, ti, si)]i=1,...,n with s1 ≥s2 ≥· · · ≥sn, resolving ties arbitrarily. First we mark each candidate as unmerged. Iterating the list, we skip merged candi- dates and report each unmerged candidate we encounter. When this happens for candidate (ri, ti, si), we find which peaks fall into the box (ri ± r) × (ti ± t) and mark them as merged, and continue iterating through the list. In this way, we greedily pick peaks with highest signal as representative for all peaks in the surrounding box. This method [16] was used by Hauschild et al. [9]. EM clustering (emc) This module uses the EM algorithm once again. Initially, each peak candidate represents a component. During the course of the algorithm, components can be merged. The remaining components will represent the picked peaks. Cluster editing (ce) We find clusters of peaks, from which we pick a repre- sentative (peak with highest signal), by solving an instance of the weighted cluster editing problem [17,18]: Let G = (V, E) be a weighted, undirected graph without loops with a symmetric similarity weight function w: V 2  →R, such that E = {{u, v} : w(u, v) ≥0}. The graph can be modi- fied by adding a non-existing or removing an existing edge {u, v}, which incurs a cost of |w(u, v)|. The costs for several modifications are added to yield the total cost. The objec- tive is to find a set of edge modifications with minimum cost such that the resulting graph consists of disjoints cliques (i.e., is transitive). When updating the variance by maximum likelihood estimation, we must be aware that the variance of a com- ponent described by only one peak tends to zero, which leads to a singularity in the Gaussian density function. Therefore, we restrict the estimated standard deviation to values above the threshold τ := 10−5 Vs/cm2. Every candidate peak is a vertex u = (ru, tu). The similarity w(u, v) between two vertices u, v depends on their distances on the r- and t-axis. We use the distance measure Function interfaces Using unified function interfaces for each step ensures the modularity of the pipeline. A preprocessing function takes an IMSMeasurement and a parameter_map manipulating the provided matrix. A module for peak modeling (pme) Peak modeling is an optional step that estimates a para- metric model of a peak shape. We have so far imple- mented one module (simply called Peak Model Estimation (pme)) using shifted Inverse Gaussian distributions, con- sider [12]. If it is not desired to model the peaks, the empty ε module (e) can be used instead. It outputs the peak list without any modification. d2(u, v) := 1 2 tu −tv t 2 + ru −rv r 2 and the similarity weight function (with a constant scaling factor b) D’Addario et al. BMC Bioinformatics 2014, 15:25 http://www.biomedcentral.com/1471-2105/15/25 D’Addario et al. BMC Bioinformatics 2014, 15:25 http://www.biomedcentral.com/1471-2105/15/25 Page 8 of 12 IMSMatrix that represents an IMSC (Sr,t), i.e., it contains the raw intensity values as a matrix. IMSMatrix that represents an IMSC (Sr,t), i.e., it contains the raw intensity values as a matrix. A whole IMSC is interpreted as a sample from a mix- ture model of different shifted Inverse Gaussians plus a uniform background noise model. Each component (peak) can then be described by seven parameters (three for both shifted Inverse Gaussians in both r- and t- dimension, plus one mixture coefficient). The challenge is to estimate the parameters correctly, especially when peaks overlap. Again, the EM algorithm is utilized for this purpose. Output The class IMSPeak describes a single peak. It stores the name of the originating measurement, its peak name (ID), retention time and reduced inverse mobility of the peaks mode, the signal intensity and the volume (if not calculated, equal to the intensity). The indices of both retention time and reduced inverse mobility are also stored. A map peak_parameters may store additional parameters, e.g., parameters estimated for inverse Gaussian distributions, as described in Section ‘A module for peak modeling (pme)’. For efficiency, each component model is evaluated only in a surrounding box enclosing the peak. Starting from the picked peak location, the box borders are expanded in all four main directions until the signal intensity drops to zero in each direction. The parame- ter expansion_size determines how much the box around the peak is expanded additionally. The class IMSPeakList stores the resulting list of such peaks found by the candidate detection, picking and mod- eling steps. Every IMSPeakList contains a list named parameter_names, which stores the names of addi- tional parameters for every peak. These are the keys for the above mentioned peak_parameters map. When two boxes intersect, both boxes are merged into their convex hull. After that process we have a set of boxes containing at least one peak. Now we can apply EM to each box independently, with the advantage of processing smaller boxes in contrast to the whole signal matrix. Starting parameters for each component are esti- mated from the locations of picked peaks and additional assumptions: The parameters are chosen such that their modes correspond to the known (r, t) values, the mean is set slightly higher (μ = mode + 10−3 index units), and the standard deviation is set to 1 index unit in both dimensions. As the model parameters have a rather tech- nical interpretation, they are translated back into mode, mean and standard deviation of the distribution, which are conveniently compared and interpreted. The output format is a .csv file with one line per peak containing the peak’s measurement name, peak name, retention time, reduced inverse mobility, signal, volume, retention time index, reduced inverse mobility index and additional parameters. Module parameters A map called parameter_map stores all peak extraction parameters (Table 1). Architecture and implementation The framework consists of a number of classes represent- ing input, output and parameters and, importantly, four function interfaces, one for each major step of a pipeline. The steps have unified interfaces to guarantee the mod- ularity of the framework and the exchangeability of the modules with future ones. A candidate detection method requires an IMS- Measurement and a parameter_map and returns an IMSPeakList. The picking functions take those results as input and return an IMSPeakList that contain Dataset We tested the framework on a dataset of 69 measure- ments, of which 39 are from different patients suffering from the same disease and 30 from a control group not showing corresponding symptoms. The disease is known but irrelevant with respect to this article and cannot be disclosed due to confidentiality agreements within the clinical study approved by the state ethics committee. Our dataset has been anonymized and serves as an illustration of the framework. For every of the 69 measurements, a manually annotated peak list was provided by an expert annotator. Input Table 1 Parameters used for evaluation Modules Parameter name Value s fftcutoff 500 s, dn smoothing_radius 4 lm area_size 9 lm, cf intensity_threshold {5, 10, 15} ce ce_weight_exponent 26 All picking tol_rt 3 All picking tol_rt_percent 0.1 All picking tol_rim 0.003 pme expansion_size 10 All computations were repeated for three different values of intensity_threshold. Table 1 Parameters used for evaluation Modules Parameter name Value s fftcutoff 500 s, dn smoothing_radius 4 lm area_size 9 lm, cf intensity_threshold {5, 10, 15} ce ce_weight_exponent 26 All picking tol_rt 3 All picking tol_rt_percent 0.1 All picking tol_rim 0.003 pme expansion_size 10 All computations were repeated for three different values of intensity_threshold. The standardized .csv format for MCC/IMS measure- ments is described by Vautz et al. [19,20]. A more efficient binary format (.ims) has also been developed inter- nally. An abstract class IMSFile provides the interface for loading and storing those formats, and the classes IMSFileCSV and IMSFileIMS instantiate the interface for the respective format. The class IMSMeasurement stores a sequence of retention time points R, a sequence of drift time points and (proportionally) reduced inverse mobilities T. Addi- tionally, a measurement_parameters map stores all meta information e.g. date, time, name or various sam- ple information of a measurement. It also stores an D’Addario et al. BMC Bioinformatics 2014, 15:25 http://www.biomedcentral.com/1471-2105/15/25 Page 9 of 12 http://www.biomedcentral.com/1471-2105/15/25 a subset of the input list. Finally the modeling step requires again the IMSMeasurement in addition to an IMSPeakList and the parameter_map. This step returns an IMSPeakList of the same size as the input one. To augment a particular step with a new module, these interfaces must be used. Figure 6 Comparing the results of all pipelines with the manually picked peaks according to sensitivity and PPV. The green crosses indicate the Pareto front. Top, middle and bottom figure correspond to signal intensity thresholds I = 5, 10, 15, respectively. The dashed lines separate two clusters of pipelines. Evaluation of pipelines BMC Bioinformatics 2014, 15:25 http://www.biomedcentral.com/1471-2105/15/25 Page 10 of 12 Table 3 Pipelines of the Pareto front for signal threshold I = 10 Pipeline G d Pipeline dn-s -bc-cf-ce 0.741 0.776 dn-s -bc-cf-ce dn-bc-s -cf-ce 0.736 0.783 s -dn-bc-cf-ce bc-dn-s -cf-ce 0.733 0.785 s -bc-dn-cf-ce dn-bc-s -cf-emc 0.732 0.811 dn-bc-s -cf-ce bc-dn-s -cf-emc 0.729 0.822 bc-dn-s -cf-ce s -bc-dn-cf-emc 0.728 0.825 dn-bc-s -cf-emc s -dn-bc-cf-emc 0.727 0.827 bc-s -dn-cf-ce dn-bc-s -lm-ce 0.720 0.836 bc-dn-s -cf-emc dn-bc-s -cf-mi 0.717 0.838 s -bc-dn-cf-emc s -dn-bc-cf-mi 0.709 0.839 s -dn-bc-cf-emc Table 3 Pipelines of the Pareto front for signal threshold I 10 the sensitivity SENS := TP/(TP + FN) and the positive predictive value PPV := TP/(TP + FP). Their geomet- ric mean G := √ SENS · PPV summarizes both measures, which is referred to as Fowlkes-Mallows index [21]. Fur- ther, the Jaccard index between two peak lists is J := TP / (FN + TP + FP) ∈[0, 1]. From this, we derive a distance measure d := 1/J −1 ∈[0, ∞]. The distance and geomet- ric mean are calculated separately for each combination of pipeline and measurement. To determine these quantities for a particular pipeline, we average over all measure- ments of the dataset. It remains to define what it means that “the same” peak has been detected by both methods, since the location parameters (r, t) may differ slightly. All peak picking modules can be used for this decision, and we chose “Merging by Signal Intensity” (ms). Imagine a box around every manually annotated peak (r, t) of widths 2r and 2t, respectively. Then we successively count each box containing at least one automatically found peak and delete it. In case of two or more peaks within the box we count the closest one. groups. The first group has both relatively low sensitivity and low positive predictive value, while the second one has high values for both measures. We note that the pipelines of the first group are characterized by the utilization of the pme module (see Additional file 1: Supplements A, B and C). By modeling, the peak coordinate moves slightly, yielding larger average differences to the manual anno- tation based on grid coordinates. So module pme seems to be unnecessary. However, the volume of a peak may contain important information (not evaluated here), and we cannot infer it only from the position and intensity at those coordinates alone. Evaluation of pipelines Concerning the threshold I, the choice of 10 yields the best results. For both I = 10 and 15, the best pipeline is dn-s-bc-cf-ce. The top values in Table 3 range around 0.70 for the geometric mean. We note that individual measurement properties (high or low noise, characteristic VOCs, etc.) were not taken into consideration for choosing the module parameters. An additional step of parameter estimation from global measurement properties would likely improve the results. Evaluation of pipelines By combining the implemented modules, we obtain 108 individual pipelines. We name the pipelines by concate- nating the shortcuts of the used modules in order. For example, the pipeline using (in that order) the mod- ules Smoothing, De-Noising, Baseline Correction, Local Maxima, EM Clustering and No Modeling is named s-dn-bc-lm-emc-e. There are not 144 pipelines because of redundancy between pipelines using the empty module as fourth step and those using it as third one (consider the example before and s-dn-bc-lm-e-emc, which is the same computational pipeline). We used the parameters shown in Table 1. To evaluate each pipeline, we compare the final obtained peak list with one that was manually annotated by an expert MCC/IMS development engineer. For the com- parison, we considered only peaks with a retention time above 5 s and an inverse reduced mobility above 0.48 Vs/cm2, as is standard practice. Agreement of an automatically obtained peak list with that obtained by a domain expert is generally considered favourable. However, one should be aware that manu- ally annotated list may also be incomplete or contain extraneous peaks. Nevertheless considering the manually annotated peaks ground truth, we compute the follow- ing quantities. Peaks detected by both methods, manual and automatic, within one measurement are true posi- tives (TP). (Below, we address the question when peaks with slightly different location parameters should be con- sidered the same.) Accordingly, manually annotated peaks that are not detected by the pipeline are false negatives (FN) and automatically detected peaks not found in the manual annotation are false positives (FP). We compute Figure 6 Comparing the results of all pipelines with the manually picked peaks according to sensitivity and PPV. The green crosses indicate the Pareto front. Top, middle and bottom figure correspond to signal intensity thresholds I = 5, 10, 15, respectively. The dashed lines separate two clusters of pipelines. D’Addario et al. Ranking the pipelines Figure 6 shows a plot of SENS against PPV for each pipeline for different parameter values of the signal inten- sity threshold I. The Pareto front is visualized in each plot. Considering only pipelines that are Pareto-optimal, we rank the ten best ones by their geometric mean and distance separately. The results of the rankings are pre- sented in Tables 2, 3 and 4 for signal intensity thresholds I ∈{5, 10, 15}, respectively. Note that each of these tables reports two rankings, the first two columns for the geo- metric mean G and the both remaining columns for the distance d. We find that, for the candidate detection step, almost all Pareto-optimal pipelines use Cross Finding (cf). The picking step is best done by Cluster Editing (ce). For every signal intensity threshold I, the pipelines split into two Table 4 Pipelines of the Pareto front for signal threshold I = 15 Table 2 Pipelines of the Pareto front for signal threshold I = 5 Pipeline G d Pipeline bc-s -dn-cf-ce 0.729 0.850 bc-s -dn-cf-ce bc-s -dn-lm-ce 0.726 0.853 bc-s -dn-lm-ce dn-bc-s -cf-ce 0.725 0.855 bc-dn-s -cf-ce dn-bc-s -lm-ce 0.725 0.861 dn-bc-s -lm-ce bc-s -dn-cf-emc 0.697 0.862 bc-dn-s -lm-ce bc-dn-s -cf-emc 0.697 0.868 dn-bc-s -cf-ce dn-bc-s -cf-emc 0.693 1.012 bc-s -dn-cf-emc dn-bc-s -cf-mi 0.671 1.016 bc-s -dn-lm-emc s -dn-bc-lm-ce 0.658 1.018 bc-dn-s -cf-emc dn-s -bc-lm-ce 0.658 1.021 bc-dn-s -lm-emc Table 4 Pipelines of the Pareto front for signal threshold I = 15 Pipeline G d Pipeline dn-s -bc-cf-ce 0.718 0.916 dn-s -bc-cf-ce s -dn-bc-cf-ce 0.718 0.916 s -dn-bc-cf-emc s -dn-bc-cf-emc 0.718 0.916 s -bc-dn-cf-emc dn-s -bc-cf-emc 0.716 0.921 dn-s -bc-cf-emc s -dn-bc-cf-mi 0.707 0.923 s -dn-bc-cf-ce dn-s -bc-cf-mi 0.706 0.923 s -bc-dn-cf-ce dn-bc-s -cf-emc 0.697 0.959 s -dn-bc-cf-mi dn-bc-s -cf-ce 0.696 0.959 s -bc-dn-cf-mi bc-dn-s -cf-emc 0.695 0.962 dn-s -bc-cf-mi bc-dn-s -cf-ce 0.693 1.045 dn-bc-s -cf-emc Table 2 Pipelines of the Pareto front for signal threshold I 5 D’Addario et al. BMC Bioinformatics 2014, 15:25 http://www.biomedcentral.com/1471-2105/15/25 Page 11 of 12 D’Addario et al. BMC Bioinformatics 2014, 15:25 http://www.biomedcentral.com/1471-2105/15/25 Discussion and conclusion The framework with the modules described in this arti- cle are available at http://www.rahmannlab.de/research/ ims, as well as the anonymized datasets and Additional file 1: Supplement. We presented the first framework for fully automatic pro- cessing of MCC/IM measurements, consisting of different modules for four distinct computational steps. The pre- sented framework processes a single IM measurement and outputs a peak list within a few seconds. A domain expert, who before had the time consuming task of peak annotation, may now quickly verify the resulting auto- matically generated peak list and manually reject a few potential false positives. In practice, higher sensitivity of the automated pipeline (at the cost of more false positive predictions) may be desirable, as this type of error can be better compensated by statistical learning methods during classification than a false negative rate. Competing interests d l h h We declare that we have no competing financial interests. We do declare that JIB is chairman of a company, B & S Analytik GmbH that builds and sells ion mobility spectrometers. However, our algorithms are general-purpose and not restricted to their instruments. References 1. Koczulla R, Hattesohl A, Schmid S, Bödeker B, Maddula S, Baumbach JI: MCC/IMS as potential noninvasive technique in the diagnosis of patients with COPD with and without alpha 1-antitrypsin deficiency. Int J Ion Mobility Spectrom 2011, 14(4):177–185. 2. Armenta S, Alcala M, Blanco M: A review of recent, unconventional applications of ion mobility spectrometry (IMS). Analytica Chimica Acta 2011, 703(2):114–123. 3. Westhoff M, Litterst P, Freitag L, Urfer W, Bader S, Baumbach JI: Ion mobility spectrometry for the detection of volatile organic compounds in exhaled breath of patients with lung cancer: results of a pilot study. Thorax 2009, 64(9):744–748. y 4. Bödeker B, Vautz W, Baumbach JI: Peak comparison in MCC/IMS-data - searching for potential biomarkers in human breath data. Int J Ion Mobility Spectrom 2008, 11(1–4):89–93. 5. Bunkowski A, Bödeker B, Bader S, Westhoff M, Litterst P, Baumbach JI: MCC/IMS signals in human breath related to sarcoidosis - results of a feasibility study using an automated peak finding procedure. J Breath Res 2009, 3(4):046001. Authors’ contributions The best pipeline achieves a geometric mean of sensitiv- ity and positive predictive value of 0.741 when compared to a manual expert manual annotation, without tuning the parameters for the single modules. Since the manu- ally extracted peaks are annotated by one single expert, one cannot be certain whether that solution is fully cor- rect; some of the peaks evaluated as false positives in our pipelines might in fact be false negatives of the expert, but this is difficult to quantify, except on a case-by-case basis. MDA and DK developed and implemented the framework including every presented module. MDA, DK and SR drafted the manuscript and JIBB provided the data for evaluation. All authors read and approved the final manuscript. Received: 29 August 2013 Accepted: 17 January 2014 Published: 22 January 2014 Received: 29 August 2013 Accepted: 17 January 2014 Published: 22 January 2014 The state of the art today is that every expert has his own “manual procedure” for peak extraction, based on certain human-observable features of the visualized data matrix. We observed two experts and attempted to infer their “internal algorithm” and express this knowledge as our parameters. The most significant parameter values were determined by domain experts’ experiences, i.e. the tol- erances used for the picking step. The intensity threshold from the candidate detection step was tested empirically. We reported on three different values (Section ‘Results’). For the other parameters we used values selected by our own experience. These last parameters do not influence the results as much as the previously mentioned ones. Acknowledgements MDA, DK, JIBB, SR are supported by the Collaborative Research Center (Sonderforschungsbereich, SFB) 876 “Providing Information by Resource- Constrained Data Analysis” within project TB1 (http://sfb876.tu-dortmund.de). We thank Benjamin Yip and Henning Funke for preliminary work. Additional file 1: Supplement. Additional file 1: Supplement. Author details 1 1Collaborative Research Center SFB 876, TU Dortmund University, Dortmund, Germany. 2B & S Analytik, BioMedical Center, Dortmund, Germany. 3Genome Informatics, Institute of Human Genetics, Faculty of Medicine, University of Duisburg-Essen, Essen, Germany. Hauschild et al. [9] discovered that the hand picking method by domain experts yields the best results for clas- sification compared to automatic peak picking methods (e.g. IPHEx [22] or Visual Now [23]). Thus it is reasonable to compete with a domain expert. Future work f Our future work will consist in the effort to estimate as many of the algorithms’ parameters as possible from the given data matrix. The tolerance parameters of the picking step were so far determined by domain experts’ experiences, and it will be difficult to learn them purely from the data. For some other parameters it may be pos- sible, e.g. for the signal intensity by determining the noise level of the background noise. Also, for the area size of the peak candidate detection step and the expansion size for the peak modeling we see a possibility to automatically determine the values. 6. Westhoff M, Litterst P, Maddula S, Bödeker B, Rahmann S, Davies AN, Baumbach JI: Differentiation of chronic obstructive pulmonary disease (COPD) including lung cancer from healthy control group by breath analysis using ion mobility spectrometry. Int J Ion Mobility Spectrom 2010, 13(3–4):131–139. 6. Westhoff M, Litterst P, Maddula S, Bödeker B, Rahmann S, Davies AN, Baumbach JI: Differentiation of chronic obstructive pulmonary disease (COPD) including lung cancer from healthy control group by breath analysis using ion mobility spectrometry. Int J Ion Mobility Spectrom 2010, 13(3–4):131–139. 7. Ulanowska A, Ligor M, Amann A, Buszewski B: Determination of volatile organic compounds in exhaled breath by ion mobility spectrometry. Chemia Analityczna 2008, 53(6):953–965. 8. Eiceman GA, Karpas Z: Drift Tubes for Mobility Spectrometers. Ion Mobility Spectrometry: Boca Raton: CRC Press; 2010. 9 H hild AC K ki D D’Add i M B b h JI R h S Baumbach J: Peak detection method evaluation for ion mobility spectrometry by using machine learning approaches. Metabolites 2013, 3(2):277–293. Baumbach J: Peak detection method evaluation for ion mobility spectrometry by using machine learning approaches. Metabolites 2013, 3(2):277–293. Page 12 of 12 Page 12 of 12 D’Addario et al. BMC Bioinformatics 2014, 15:25 http://www.biomedcentral.com/1471-2105/15/25 10. Kreuder AE, Buchinger H, Kreuer S, Volk T, Maddula S, Baumbach J: Characterization of propofol in human breath of patients undergoing anesthesia. Int J Ion Mobility Spectrom 2011, 14:167–175. 11. Dempster AP, Laird NM, Rubin DB: Maximum likelihood from incomplete data via the EM algorithm. J R Stat Soc Ser B (Methodological) 1977, 39:1–38. 12. Kopczynski D, Baumbach JI, Rahmann S: Peak Modeling for Ion Mobility Spectrometry Measurements. In Signal Processing Conference (EUSIPCO) 2012 Proceedings of the 20th European, Bucharest, Romania: IEEE; 2012:1801–1805. 13. Future work f Bader S, Urfer W, Baumbach JI: Preprocessing of ion mobility spectra by lognormal detailing and wavelet transform. Int J Ion Mobility Spectrom 2008, 11(1–4):43–49. 14. Savitzky A, Golay MJE: Smoothing and differentiation of data by simplified least squares procedures. Anal Chem 1964, 36(8): 1627–1639. 15. Fong SS, Rearden P, Kanchagar C, Sassetti C, Trevejo J, Brereton RG: Automated peak detection and matching algorithm for gas chromatography-differential mobility spectrometry. Anal Chem 2011, 83(5):1537–1546. 16. Bödeker B, Vautz W, Baumbach JI: Peak finding and referencing in MCC/IMS-data. Int J Ion Mobility Spectrom 2008, 11(1):83–87. 17. Rahmann S, Wittkop T, Baumbach J, Martin M, Truss A, Böcker S: Exact and heuristic algorithms for weighted cluster editing. In Computational Systems Bioinformatics Conference Volume 6, San Diego, California, USA. Life Science Society; 2007:391–401. 18. Böcker S, Briesemeister S, Klau GW: Exact algorithms for cluster editing: evaluation and experiments. Algorithmica 2011, 60(2):316–334. 19. Vautz W, Bödeker B, Bader S, Baumbach JI: Recommendation of a standard format for data sets from GC/IMS with sensor-controlled sampling. Int J Ion Mobility Spectrom 2008, 11(1–4):71–76. 20. Maddula S, Rupp K, Baumbach JI: Recommendation for an upgrade to the standard format in order to cross-link the GC/MSD and the MCC/IMS data. Int J Ion Mobility Spectrom 2012, 15(2):79–81. 21. Fowlkes EB, Mallows CL: A method for comparing two hierarchical clusterings. J Am Stat Assoc 1983, 78(383):553–569. 22. Bunkowski A: MCC-IMS data analysis using automated spectra processing and explorative visualisation methods. PhD thesis, University Bielefeld, Bielefeld, Germany; 2011. 23. Bader S, Urfer W, Baumbach JI: Reduction of ion mobility spectrometry data by clustering characteristic peak structures. J Chemometrics 2007, 20(3–4):128–135. doi:10.1186/1471-2105-15-25 Cite this article as: D’Addario etal.: A modular computational framework for automated peak extraction from ion mobility spectra. BMC Bioinformatics 10. Kreuder AE, Buchinger H, Kreuer S, Volk T, Maddula S, Baumbach J: Characterization of propofol in human breath of patients undergoing anesthesia. Int J Ion Mobility Spectrom 2011, 14:167–175. 11. Dempster AP, Laird NM, Rubin DB: Maximum likelihood from incomplete data via the EM algorithm. J R Stat Soc Ser B (Methodological) 1977, 39:1–38. 12. Kopczynski D, Baumbach JI, Rahmann S: Peak Modeling for Ion Mobility Spectrometry Measurements. In Signal Processing Conference (EUSIPCO) 2012 Proceedings of the 20th European, Bucharest, Romania: IEEE; 2012:1801–1805. 13. Bader S, Urfer W, Baumbach JI: Preprocessing of ion mobility spectra by lognormal detailing and wavelet transform. Int J Ion Mobility Spectrom 2008, 11(1–4):43–49. 14. Future work f Savitzky A, Golay MJE: Smoothing and differentiation of data by simplified least squares procedures. Anal Chem 1964, 36(8): 1627–1639. 15. Fong SS, Rearden P, Kanchagar C, Sassetti C, Trevejo J, Brereton RG: Automated peak detection and matching algorithm for gas chromatography-differential mobility spectrometry. Anal Chem 2011, 83(5):1537–1546. 16. Bödeker B, Vautz W, Baumbach JI: Peak finding and referencing in MCC/IMS-data. Int J Ion Mobility Spectrom 2008, 11(1):83–87. 17. Rahmann S, Wittkop T, Baumbach J, Martin M, Truss A, Böcker S: Exact and heuristic algorithms for weighted cluster editing. In Computational Systems Bioinformatics Conference Volume 6, San Diego, California, USA. Life Science Society; 2007:391–401. 18. Böcker S, Briesemeister S, Klau GW: Exact algorithms for cluster editing: evaluation and experiments. Algorithmica 2011, 60(2):316–334. 19. Vautz W, Bödeker B, Bader S, Baumbach JI: Recommendation of a standard format for data sets from GC/IMS with sensor-controlled sampling. Int J Ion Mobility Spectrom 2008, 11(1–4):71–76. 20. Maddula S, Rupp K, Baumbach JI: Recommendation for an upgrade to the standard format in order to cross-link the GC/MSD and the MCC/IMS data. Int J Ion Mobility Spectrom 2012, 15(2):79–81. 21. Fowlkes EB, Mallows CL: A method for comparing two hierarchical clusterings. J Am Stat Assoc 1983, 78(383):553–569. 22. Bunkowski A: MCC-IMS data analysis using automated spectra processing and explorative visualisation methods. PhD thesis, University Bielefeld, Bielefeld, Germany; 2011. 23. Bader S, Urfer W, Baumbach JI: Reduction of ion mobility spectrometry data by clustering characteristic peak structures. J Chemometrics 2007, 20(3–4):128–135. doi:10.1186/1471-2105-15-25 Cite this article as: D’Addario etal.: A modular computational framework for automated peak extraction from ion mobility spectra. BMC Bioinformatics 2014 15:25. Submit your next manuscript to BioMed Central and take full advantage of: • Convenient online submission • Thorough peer review • No space constraints or color figure charges • Immediate publication on acceptance • Inclusion in PubMed, CAS, Scopus and Google Scholar • Research which is freely available for redistribution Submit your manuscript at www.biomedcentral.com/submit Submit your next manuscript to BioMed Central and take full advantage of:
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https://www.frontiersin.org/articles/10.3389/fgene.2023.1140400/pdf
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A review of the genomics of neonatal abstinence syndrome
Frontiers in genetics
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cc-by
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1 Background From 2010 to 2017, the number of pregnant women with opioid-related diagnoses [e.g., opioid use disorder (OUD)] increased from 3.5 to 8.2 per 1000 delivery hospitalizations (Hirai et al., 2021). This resulted in a concomitant increase in the number of neonates with neonatal abstinence syndrome (NAS) or neonatal opioid withdrawal syndrome (NOWS), from 4.0 to 7.3 per 1000 births1. This translated to a healthcare cost of $2.5 billion between 2004 and 2014 (Winkelman et al., 2018). Despite this substantial socioeconomic burden, there remains great variation in the diagnosis and management of NAS, highlighting an urgent need for objective and validated measures to address this challenge. KEYWORDS neonatal abstinence syndrome (NAS), genetics, epigenetics, inflammation, biomarker KEYWORDS neonatal abstinence syndrome (NAS), genetics, epigenetics, inflammation, biomarker OPEN ACCESS OPEN ACCESS EDITED BY Funda Tuzun, Dokuz Eylül University, Türkiye REVIEWED BY David J. Vandenbergh, The Pennsylvania State University (PSU), United States *CORRESPONDENCE Elizabeth Yen, Elizabeth.Yen2@tuftsmedicine.org SPECIALTY SECTION This article was submitted to Pharmacogenetics and Pharmacogenomics, a section of the journal Frontiers in Genetics RECEIVED 09 January 2023 ACCEPTED 01 February 2023 PUBLISHED 10 February 2023 CITATION Yen E, Gaddis N, Jantzie L and Davis JM (2023), A review of the genomics of neonatal abstinence syndrome. Front. Genet. 14:1140400. doi: 10 3389/fgene 2023 1140400 OPEN ACCESS EDITED BY Funda Tuzun, Dokuz Eylül University, Türkiye REVIEWED BY David J. Vandenbergh, The Pennsylvania State University (PSU), United States *CORRESPONDENCE Elizabeth Yen, Elizabeth.Yen2@tuftsmedicine.org SPECIALTY SECTION This article was submitted to Pharmacogenetics and Pharmacogenomics, a section of the journal Frontiers in Genetics Elizabeth Yen1,2,3*, Nathan Gaddis4, Lauren Jantzie5 and Jonathan M. Davis1,3,6 1Department of Pediatrics, Tufts Medical Center, Boston, MA, United States, 2Mother Infant Research Institute, Tufts Medical Center, Boston, MA, United States, 3Tufts University School of Medicine, Boston, MA, United States, 4Research Triangle Institute International, Research Triangle Park, Durham, NC, United States, 5Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 6Tufts Clinical and Translational Sciences Institute, Boston, MA, United States Neonatal abstinence syndrome (NAS) is a constellation of signs of withdrawal occurring after birth following in utero exposure to licit or illicit opioids. Despite significant research and public health efforts, NAS remains challenging to diagnose, predict, and manage due to highly variable expression. Biomarker discovery in the field of NAS is crucial for stratifying risk, allocating resources, monitoring longitudinal outcomes, and identifying novel therapeutics. There is considerable interest in identifying important genetic and epigenetic markers of NAS severity and outcome that can guide medical decision making, research efforts, and public policy. A number of recent studies have suggested that genetic and epigenetic changes are associated with NAS severity, including evidence of neurodevelopmental instability. This review will provide an overview of the role of genetics and epigenetics in short and longer-term NAS outcomes. We will also describe novel research efforts using polygenic risk scores for NAS risk stratification and salivary gene expression to understand neurobehavioral modulation. Finally, emerging research focused on neuroinflammation from prenatal opioid exposure may elucidate novel mechanisms that could lead to development of future novel therapeutics. OPEN ACCESS RECEIVED 09 January 2023 ACCEPTED 01 February 2023 PUBLISHED 10 February 2023 CITATION Yen E, Gaddis N, Jantzie L and Davis JM (2023), A review of the genomics of neonatal abstinence syndrome. Front. Genet. 14:1140400. doi: 10.3389/fgene.2023.1140400 COPYRIGHT © 2023 Yen, Gaddis, Jantzie and Davis. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. TYPE Mini Review PUBLISHED 10 February 2023 DOI 10.3389/fgene.2023.1140400 TYPE Mini Review PUBLISHED 10 February 2023 DOI 10.3389/fgene.2023.1140400 TYPE Mini Review PUBLISHED 10 February 2023 DOI 10.3389/fgene.2023.1140400 frontiersin.org 4.1.1 Single nucleotide polymorphism (SNP) Our knowledge of genetic risk factors underlying NAS severity is in its infancy, mainly due to the difficulty of providing sufficient statistical power for genetic analyses. More is known about the genetics of OUD in adults, for which an estimated ~60% of the population variability is attributable to genetic factors based on twin and family studies (Kendler et al., 2003; Goldman et al., 2005). Early studies of the genetics of NAS consisted primarily of candidate SNP analyses of loci identified in studies of adult opioid dependence or loci associated with opioid and stress pathways, with inconsistent results (Oei et al., 2012; Wachman et al., 2013; Wachman et al., 2015; Mactier et al., 2017; Wachman et al., 2017). In opioid-exposed neonates, the need for pharmacotherapy was associated with SNPs in cytochrome P450 family 2 subfamily B member 6 (CYP2B6). Hypermethylation in the opioid receptor mu 1 (OPRM1) promoter was linked to worse NAS outcomes, defined by the need for ≥2 medications (Wachman et al., 2014). Another study reported that SNPs in prepronociceptin (PNOC), opioid receptor kappa 1 (OPRK1), or opioid receptor delta 1 (OPRD1) were linked to the need for ≥2 medications and longer length of hospital stay (Mactier et al., 2017). A recent review provides a comprehensive synopsis of candidate SNP studies and the loci they identified as potentially being associated with NAS severity (Wachman and Farrer, 2019). The results of the candidate SNP studies in are seen in Table 1 and provide an update on the replication status of the identified loci (discussed below). The loci include OPRM1, OPRK1, and OPRD1, the endogenous opioid peptide PNOC, the dopamine-metabolizing enzyme catechol-O-methyltransferase (COMT), and the methadone-metabolizing enzyme CYP2B6. The majority of these associations with NAS severity were point-wise significant but failed to reach experiment-wise significance when applying multiple-testing correction. 2 Current practice: Clinical evaluation and management of NAS Multiple factors contribute to the challenge of a diagnosis and management of NAS. These include maternal characteristics (type of opioid used during pregnancy, comorbid Frontiers in Genetics 01 frontiersin.org Yen et al. 10.3389/fgene.2023.1140400 4.1.2 Genome-wide association study (GWAS) y For OUD and related phenotypes, GWAS have identified a small number of genome-wide association signals and few replicable findings (Gelernter et al., 2014; Nelson et al., 2016; Polimanti et al., 2020; Song et al., 2020; Zhou et al., 2020; Sanchez-Roige et al., 2021; Gaddis et al., 2022; Kember et al., 2022). Several recent large-scale GWAS of OUD have yielded promising loci with greater statistical support and consistency across multiple cohorts which could provide insight into the genetics of NAS (Zhou et al., 2020; Sanchez-Roige et al., 2021; Gaddis et al., 2022; Kember et al., 2022). A recent NAS GWAS allowed the development of a polygenic risk score (PRS) model that demonstrated the potential of using PRS for predicting NAS severity (Bibi et al., 2022); further model development based on larger sample sizes is needed. These scoring systems also do not account for sex of the neonates. While some studies have suggested that male sex is associated with worse NAS, others have not (Jansson et al., 2010; Unger et al., 2011; Charles et al., 2017). Sex is an important biological variable that contributes to the fundamental differences seen in many diseases and pharmacologic responses (Bartz et al., 2020; Kantarci et al., 2020; Zucker and Prendergast, 2020; Sharifiet al., 2021). An urgent need exists to incorporate sex in the evaluation and management of NAS. Based on the current one-size-fits-all model, the field needs molecular and other approaches to arrive at an objective method that considers an individual’s characteristics and enables personalized evaluation and management of NAS. The first ever GWAS examining the need for pharmacotherapy as a measure of NAS severity consisted of 476 in-utero opioid- exposed term neonates; 94 were of African ancestry (AA) and 382 European ancestry (EA) (Table 1) (Bibi et al., 2022). Although the sample was small for a GWAS due to the challenge of enrolling in-utero opioid-exposed neonates, obtaining consent, and performing genetic testing, this study did identify one genome- wide significant signal on chromosome 7 upstream of the G protein regulator and sorting nexin-13 gene (SNX13), which has been 4.1 Genetics in NAS physical/mental health conditions), neonatal characteristics (gestational age, sex), and hospital-based practice variation (e.g., location of care, breastmilk, supportive care) (Bogen et al., 2017; Minozzi et al., 2020; Jansson et al., 2017; Favara et al., 2019; Yen et al., 2021; O’Connor et al., 2017; Krans et al., 2021). Clinicians assign the diagnosis of NAS using varying criteria: 1) antenatal opioid exposure, 2) presence of any withdrawal signs following birth, and/or 3) use of pharmacotherapy (Jilani et al., 2021). In an effort to address the lack of a standardized clinical definition of NAS, the US Department of Health and Human Services convened a panel that proposed two key elements to diagnose NAS; prenatal exposure of opioids (with/without other substances) and presence of 2 of 5 most common clinical signs of NAS (high-pitched cry, poor sleep, tremors, hypertonia, gastrointestinal issues) (Jilani et al., 2022a; Jilani et al., 2022b). Frontiers in Genetics 3 Knowledge gaps surrounding NAS Compounding this diagnostic challenge is lack of objective diagnostic tools. The most commonly used scoring system is the Finnegan Neonatal Abstinence Scoring System (FNASS) (Finnegan et al., 1975). Given the intricacies of the FNASS, attempts have been made to simplify the system with the introduction of multiple approaches including Eat, Sleep, Console (Gomez Pomar et al., 2017; Grossman et al., 2018; Devlin et al., 2020; Kocherlakota et al., 2020). Utilizing other systems such as the NICU Network Neurobehavioral Scale (NNNS) that incorporates neurologic and behavioral measures and signs of stress may provide improved diagnostic information (Lester et al., 2004). Despite the simplification, all scoring systems are subjective and require education/training to minimize inter- rater variability (Timpson et al., 2018; Chin Foo et al., 2021). Scoring systems are tools that may be biased by subjective factors, resulting in over- and under-medication which could actually increase long-term risks. frontiersin.org 4 Emerging biomarker research in NAS Researchers have examined molecular mechanisms, genetic and epigenetic alterations that may increase the risk of more severe NAS and the need for pharmacotherapy (which prolongs hospitalizations and increases costs). Several of these approaches are quite promising and have contributed to a better understanding of the pathogenesis of NAS. 02 frontiersin.org Yen et al. 10.3389/fgene.2023.1140400 LE 1 Variants with evidence of association with NAS phenotypes. TABLE 1 Variants with evidence of association with NAS phenotypes. SNP Gene Phenotype Ancestry N Study type Candidate SNP replication (EA**, N = 113) [Oei et al. (2012)] GWAS replication (AA + EA, N = 476) [Bibi et al. (2022)] rs1799971 [Wachman et al. (2013); Wachman et al. (2015)] OPRM1 LOS EA** 86 Candidate SNP ND No NAS Treatment rs204076 [Wachman et al. (2015)]* OPRD1 LOS EA** 86 Candidate SNP ND No ≥2 Meds rs2614095 [Wachman et al. (2015)]* PNOC LOS EA** 86 Candidate SNP No No* ≥2 Meds rs351776 [Wachman et al. (2015)]* PNOC LOS EA** 86 Candidate SNP No No ≥2 Meds rs4732636 [Wachman et al. (2015)]* PNOC LOS EA** 86 Candidate SNP No No NAS Treatment ≥2 Meds rs702764 [Wachman et al. (2015)]* OPRK1 ≥2 Meds EA** 86 Candidate SNP ND No rs4680 [Wachman et al. (2013)] COMT LOS EA** 86 Candidate SNP No No NAS Treatment ≥2 Meds rs740603 [Wachman et al. (2015)]* COMT LOS EA** 86 Candidate SNP No No NAS Treatment rs3745274 [Mactier et al. (2017)] CYP2B6 NAS Treatment NR 21 Candidate SNP ND No rs2279343 [Mactier et al. (2017)] CYP2B6 NAS Treatment NR 21 Candidate SNP ND ND rs73313786 [Bibi et al. (2022)] SNX13 NAS Treatment AA + EA 476 GWAS ND ND NAS, neonatal abstinence syndrome; LOS, length of hospital stay; EA, European ancestry; AA, African ancestry; ND, not done; NR, not reported. *Associations demonstrated point-wise significance at α = 0.05, but not experiment-wise significance. **Cohorts were predominantly EA (98% in the candidate gene discovery cohort (Wachman et al., 2013, Wachman et al., 2015), 88% in the candidate SNP, replication cohort (Wachman et al., NAS, neonatal abstinence syndrome; LOS, length of hospital stay; EA, European ancestry; AA, African ancestry; ND, not done; NR, not reported. *Associations demonstrated point-wise significance at α = 0.05, but not experiment-wise significance. **Cohorts were predominantly EA (98% in the candidate gene discovery cohort (Wachman et al., 2013, Wachman et al., 2015), 88% in the candidate SNP, 2017)). Frontiers in Genetics frontiersin.org 4 Emerging biomarker research in NAS affecting individual variation in responses to opioids (Table 2). These adult studies have identified 25 independent loci and it will be important to determine whether any of these loci are also associated with NAS severity. Only one locus (OPRM1) has been associated with NAS severity, but this finding was not replicated in the NAS GWAS. Of the 25 loci identified in adults, the ones with greatest association with NAS severity in the gene-based analysis performed for the GWAS study are: 1) potassium calcium-activated channel subfamily N member 1 (KCNN1) which regulates neuronal excitability and potassium ion trafficking (p = 0.00024) (Kember et al., 2022); 2) solute carrier family 2 member 9 (SLC2A9) from which is a member of the facilitative glucose transporter family (p = 0.035) (Song et al., 2020); and 3) cornichon family AMPA receptor auxiliary protein 3 (CNIH3) which has channel regulator activity in associated with heart failure, neutrophil counts, high density lipoprotein cholesterol level, apolipoprotein A1 level, and mean platelet volume (Willer et al., 2013; Li et al., 2014; Chen et al., 2020; Richardson et al., 2020; Vuckovic et al., 2020). SNX13 has not previously been associated with addiction, but the related SNX27 has been implicated in attenuating response to cocaine in mice (Munoz and Slesinger, 2014; Rifkin et al., 2018). Given the sample size, it will be important to replicate these findings in an independent dataset. The GWAS failed to replicate any of the associations identified in the candidate SNP studies (Table 1). However, in a gene-based analysis of the GWAS results, OPRD1 demonstrated some association (p = 0.014) as did PNOC (p = 0.073). Large-scale adult GWAS of phenotypes related to opioid abuse/ dependence have provided greater insight into the genetic loci 03 frontiersin.org Yen et al. 10.3389/fgene.2023.1140400 TABLE 2 Summary of genome-wide significant loci identified in studies of opioid use disorder and related phenotypes in adults. Study Phenotype Ancestry (N) Variant-based loci Gene-based loci Gelernter et al. (2014) DSM-IV OD AA (5,432) KCNG2 NR EA (6,877) Nelson et al. (2016) OD EA (2,637) CNIH3 NR Polimanti et al. (2020) DSM-IV OD AA (7,138) C18orf32 C18orf32 Song et al. (2020) ICD-9/10 OUD EA (21,310) DEFB131/SLC2A9/RP11–1396O13.13/ZNF518B* NR Zhou et al. (2020) ICD-9/10 OUD EA (82,707) OPRM1 NR DSM-IV OD Sanchez-Roige et al. (2021) POU EA (132,113) KDM4A/PTPRF*; LRRIQ3 KDM4A; PTPRF; ARTN Gaddis et al. 4 Emerging biomarker research in NAS (2022) OA (DSM-IV OD or FOU- based) EA (88,114**) OPRM1 OPRM1; PPP6C; FURIN Kember et al. (2022) ICD-9/10 OUD AA (88,498) NNT; CDKAL1/SOX4*; BTNL2; OPRM1; MRS2; TSNARE1; SCAI/ RABEPK*; FBXW4; NCAM1; FURIN; KCNN1; RNF114; chromosome 10 locus CHRM2; OPRM1; FTO; DRD2 EA (302,585) HA (34,861) ICD, international classification of diseases; DSM, diagnostic and statistical manual of mental disorders; OUD, opioid use disorder; OD, opioid dependence; EA, European ancestry; AA, African ancestry; NR, none reported; POU, problematic prescription opioid use; OA, opioid addiction; FOU, frequency of use). *Gene mapping indeterminate. **Effective sample size. ICD, international classification of diseases; DSM, diagnostic and statistical manual of mental disorders; OUD, opioid use disorder; OD, opioid dependence; EA, European ancestry; AA, African ancestry; NR, none reported; POU, problematic prescription opioid use; OA, opioid addiction; FOU, frequency of use). *Gene mapping indeterminate. **Effective sample size. 5p, and miR-421 predicted the need for pharmacotherapy (area under the curve/AUC of 0.85) and length of hospital stay (AUC 0.90). Adding a few more miRNAs enhanced predictive validity of both models. the dendritic shaft and postsynaptic membrane and has been associated with schizophrenia (p = 0.061) (Drummond et al., 2012; Nelson et al., 2016). Like KCNN1, sorting nexins related to SNX13 (e.g., SNX14, SNX27) seem to have a role in regulating neuronal excitability which may cause an attenuated response to cocaine in mice (Huang et al., 2014; Munoz and Slesinger, 2014; Rifkin et al., 2018). Although dopamine receptor type (DRD2) is a key reward gene in OUD and has been extensively studied in adults, its role in NAS is not well elucidated. Oei et al. (2012) demonstrated that DRD2 polymorphisms were detectable in stored blood spots. Furthermore, the ins variant of the −141C Del/Ins polymorphism (located in the promoter region) was more prevalent in non-exposed compared to opioid-exposed neonates who did not require pharmacotherapy. The role of dopamine in NAS is also evident in neonatal salivary transcriptomic studies by Yen et al. (2019). Neonates with NAS have aberrant feeding behavior, especially those with more severe withdrawal. Using drops of saliva, Yen et al. demonstrated that DRD2 expression was significantly higher in opioid-exposed males than females, evidence of the sex-specific impact of prenatal opioids. Furthermore, a positive correlation was found between DRD2 expression and feeding volume suggesting that excessive and dysregulated feeding in NAS may be a compensatory mechanism responding to the abrupt end of the opioid supply at birth. 4.1.3 Other genetic research in NAS g In a study of 67 neonates (half opioid-exposed), plasma brain-derived neurotrophic factor (BDNF) was significantly elevated in opioid-exposed neonates compared to non-exposed neonates, suggesting that plasma BDNF might correlate with NAS severity (Subedi et al., 2017). Mahnke et al. (2022) demonstrated that three extracellular microRNAs (miRNAs) in the umbilical cord plasma of opioid-exposed neonates were predictive of NAS severity. In particular, miR-128-3p, miR-30c- Frontiers in Genetics 4 Emerging biomarker research in NAS The implication of this upregulated reward signaling on future reward-seeking behavior is yet unknown. Based on the results of our GWAS on NAS severity, we were able to develop a preliminary set of variants for calculating a PRS for predicting need for NAS treatment (Bibi et al., 2022). The PRS was developed in a training set of 290 EA neonates from the GWAS and it was confirmed to have good predictive ability in independent validation sets of 92 EA and 94 AA neonates when using effect sizes calculated in the validation sets. However, to predict need for NAS treatment in the clinical setting, it is necessary to calculate PRS using the effect sizes from previous analyses, not the neonate being assessed. In this scenario, the PRS did not effectively predict whether a neonate required NAS treatment. While these results demonstrate the potential of PRS for clinical assessment of NAS severity, larger sample sizes are needed to develop more effective PRS models. frontiersin.org 4.2 Epigenetics of NAS Although several studies have demonstrated that genetic factors may explain the variability of expression seen in NAS, epigenetic variation in the OPRM1 gene has also been linked to NAS severity. Cytosine methylation of DNA is a known epigenetic mechanism 04 frontiersin.org Yen et al. 10.3389/fgene.2023.1140400 central immune response by binding TLR4 and an accessory protein known as myeloid differentiation protein 2 (MD-2), inducing TLR4 oligomerization and nuclear factor kappa B (NFκB) activation (Wang et al., 2012). This increases the major pro- inflammatory cytokines interleukin 1-beta (IL-1β), tumor necrosis alpha (TNFα), interleukin 6 (IL-6), and monocyte chemoattractant protein-1 (MCP-1/CCL2) and C-X-C motif ligand 1 (CXCL1) (Coller and Hutchinson, 2012). Methadone induces many of these cytokines in the peripheral circulation and brain at P10, approximately human term equivalent (Jantzie et al., 2020). Opioids also activate NFκB, which promotes transcription of opioid receptors and peptides, propagating a detrimental intracellular signaling cascade (Wang et al., 2004; Chen et al., 2007; Rehni et al., 2008; Sawaya et al., 2009; Seney et al., 2021). In adults, microglia have been implicated as a driver for opioid- induced neuroplasticity, catalyzing changes in extracellular matrix, synaptic and dendritic structures, and are proposed to be a cellular bridge connecting opioids to the neural-immune system (Zhang et al., 2020b; Ryu et al., 2021; Seney et al., 2021). Opioid-induced glial activation may serve as an important mechanism underlying drug addiction by opposing opioid analgesia in the mature CNS and enhancing opioid tolerance, dependence, and reward (Hutchinson et al., 2008; Watkins et al., 2009). that results in the addition of a methyl group to cytosine residues of cytosine:guanine (CpG) dinucleotides. Chronic in utero opioid exposure may increase methylation at specific CpG sites within promoter regions of a gene, potentially increasing or decreasing gene expression (Nielsen et al., 2012; Doehring et al., 2013). Wachman et al. (2014) obtained DNA from 86 neonates receiving pharmacotherapy for NAS and measured methylation levels at 16 OPRM1 CpG sites. Increased methylation was detected in multiple areas within the OPRM1 promoter, with the highest levels in neonates with the most severe NAS, consistent with gene silencing. In a follow-up study, OPRM1 methylation was measured in 68 neonates who were exposed to antenatal opioids and their mothers (Wachman et al., 2018). 4.2 Epigenetics of NAS While higher levels at the −18, −14, and +23 CpG sites were associated with receipt of pharmacotherapy in neonates, elevations in mothers were associated with an increased length of neonatal hospital stay, confirming prior findings. In contrast, when placental methylation of the OPRM1 promoter was analyzed in opioid exposed and non-exposed placentas, no significant associations with neonatal outcome was noted (Wachman et al., 2020). While these studies suggested that increased methylation of OPRM1 is associated with more severe NAS, Camerota et al. (2022) hypothesized that pharmacotherapy for NAS would result in decreased DNA methylation and improvements in neonatal neurobehavior. They collected DNA from 37 neonates with NAS before and after treatment and examined methylation at 4 CpG sites within the OPRM1 gene. Path analysis was used to examine associations with pharmacotherapy, DNA methylation, and NNNS summary scores. DNA methylation did decrease in 1 of 4 CpG sites and was accompanied by less excitability, hypertonia, lethargy, signs of stress and abstinence, and abnormal movement after treatment was completed. Greater decreases in DNA methylation were associated with the most significant decreases in excitability and hypertonia on the NNNS. This study is the first to suggest that pharmacologic treatment in NAS may directly influence epigenetics and neonatal neurobehavior. Further studies are needed in treated and untreated neonates in order to establish a more definitive association. Jantzie et al. (2020) demonstrated that opioid-induced brain injuries shared many features of a profound neuroinflammatory disease characterized by the white matter loss and axonal injury seen in non-opioid brain injuries (Newville et al., 2020; Vasan et al., 2021; Madurai et al., 2022). Antenatal opioids primed the immune system with baseline elevations in cytokines/chemokines as well as exaggerated inflammatory responses in peripheral blood mononuclear cells after stimulation with lipopolysaccharide. At term equivalent age, antenatal opioids increased TLR4 and myeloid differentiation primary response 88 (MyD88) mRNA in the fetal brain in conjunction with glial activation, evidenced by increased expression of ionized-calcium binding adaptor molecule 1 (Iba1) and changes in microglial morphology and activation. The peripheral inflammation, immune priming, and sustained peripheral immune reactivity (SPIHR) extended beyond the neonatal period (Jantzie et al., 2020; Newville et al., 2020). Even as markers of serum inflammation and SPIHR normalized in adulthood, opioid-induced increases in cerebral immune cell populations (neutrophils and regulatory T-cells) remained (Madurai et al., 2022). 4.2 Epigenetics of NAS Maturing rats with prenatal opioid exposure also had reduced fractional anisotropy (FA) in major white matter tracts, as well as marked loss in cerebral microstructure and abnormalities in directional diffusion. Such robust systemic inflammatory response and immune dysfunction were accompanied by cognitive deficits well into adulthood, evidence of lasting inflammatory impact of antenatal opioids (Jantzie et al., 2020; Madurai et al., 2022). 4.3.2 Neonatal studies While the impact of prenatal opioids on the developing brain and neurodevelopmental outcomes has been studied in neonates (Yuan et al., 2014; Monnelly et al., 2017; Oei et al., 2017; Sirnes et al., 2017; Merhar et al., 2019; Yeoh et al., 2019; Lowe et al., 2022; Radhakrishnan et al., 2022), the role of inflammation is unknown. Based on the emerging animal data demonstrating the pro- 4.3 Genetic evidence of inflammation as a potential mechanism for NAS Emerging animal data highlight the role of inflammation in potentiating the effects of opioids in drug addiction. Opioids bind with toll-like receptor type 4 (TLR4) and propagate the inflammatory cascade through the release of cytokines and chemokines which precipitate opioid tolerance and dependency (Hutchinson et al., 2012; Wang et al., 2012; Zhang et al., 2020a). There is an urgent need to better understand the impact of inflammation in NAS as it may contribute to the immediate signs of withdrawal and provide the genetic underpinning of the long-term neurodevelopmental effects of antenatal opioids. Frontiers in Genetics frontiersin.org 4.3.1 Animal studies TLR4 signaling in the mature central nervous system occurs in response to many types of opioids (e.g., methadone, morphine, buprenorphine, oxycodone) (Jacobsen et al., 2014). Opioids induce a 05 frontiersin.org Yen et al. 10.3389/fgene.2023.1140400 genetic and epigenetic changes resulting from antenatal opioid exposure. Such advancement is key to the systematic understanding and prediction of NAS severity and the discovery of predictive biomarkers that are readily validated. Emerging animal and human data point to the crucial role of antenatal opioids on inflammatory pathways/gene expression in a sex-specific manner. This highlights the potential of non-opioid therapeutics targeting anti-inflammatory pathways. It is important to consider biological variables such as sex and carefully account and adjust for the confounding factors inherent to this type of research. There is also an urgent need to generate larger datasets that validate findings from smaller studies to arrive at robust genetic and epigenetic biomarkers that can be linked to brain structure and function in order to improve neurodevelopmental outcomes of these high-risk neonates. inflammatory effects of antenatal opioids on the offspring, Yen et al. (2022) conducted a novel pilot study to understand the role of inflammation in NAS. Neonatal salivary transcriptomic and brain magnetic resonance imaging (MRI) data demonstrate that opioid- exposed females, regardless of the need for pharmacotherapy, had greater expression of C-C motif chemokine ligand 2 (CCL2) and CXCL1 than males. MRI showed a higher incidence of punctate white matter hyperintensity in opioid-exposed compared to non- exposed neonates, with female predominance. Salivary transcriptomics also showed significantly higher expression of IL1β, IL6, TNFα, and IL10 in opioid-exposed neonates with white matter hyperintensity than in those without it. While this pilot study replicated the findings of punctate white matter injury by Merhar et al. (2019), salivary transcriptomic data from this study were the first to suggest the genetic mechanisms by which inflammation may underlie sex-specific white matter injury in opioid-exposed neonates. In a small subset of neonates, opioid- exposed neonates had smaller head circumference and qualitatively reduced FA in major white matter tracts compared to non-exposed neonates (Sikka et al., 2022). This novel research highlights the sex- specific and pro-inflammatory effects of antenatal opioid exposure and supports prior human and animal studies demonstrating the adverse effects of antenatal opioid exposure on brain development at both macro- and micro-structural levels (Monnelly et al., 2017; Jantzie et al., 2020). References 746,667 individuals from 5 global populations. Cell 182 (5), 1198–1213.e14. doi:10.1016/j.cell.2020.06.045 Bartz, D., Chitnis, T., Kaiser, U. B., Rich-Edwards, J. W., Rexrode, K. M., Pennell, P. B., et al. (2020). Clinical advances in sex- and gender-informed medicine to improve the health of all: A review. JAMA. Intern. Med. 180, 574–583. doi:10.1001/jamainternmed. 2019.7194 Bartz, D., Chitnis, T., Kaiser, U. B., Rich-Edwards, J. W., Rexrode, K. M., Pennell, P. B., et al. (2020). Clinical advances in sex- and gender-informed medicine to improve the health of all: A review. JAMA. Intern. Med. 180, 574–583. doi:10.1001/jamainternmed. 2019.7194 746,667 individuals from 5 global populations. Cell 182 (5), 1198–1213.e14. doi:10.1016/j.cell.2020.06.045 Chen, Y. L., Law, P. Y., and Loh, H. H. (2007). Action of NF-kappaB on the delta opioid receptor gene promoter. Biochem. Biophys. Res. Commun. 352, 818–822. doi:10. 1016/j.bbrc.2006.11.103 Bibi, S., Gaddis, N., Johnson, E. O., Lester, B. M., Kraft, W., Singh, R., et al. (2022). Polygenic risk scores and the need for pharmacotherapy in neonatal abstinence syndrome. Ped. Res. Aug. 16. doi:10.1038/s41390-022-02243-0 Bibi, S., Gaddis, N., Johnson, E. O., Lester, B. M., Kraft, W., Singh, R., et al. (2022). Polygenic risk scores and the need for pharmacotherapy in neonatal abstinence syndrome. Ped. Res. Aug. 16. doi:10.1038/s41390-022-02243-0 Chin Foo, C. A., Dansereau, L. M., Hawes, K., Oliveira, E. L., and Lester, B. M. (2021). Improving the assessment of neonatal abstinence syndrome (NAS). Children 8, 685. doi:10.3390/children8080685 Bogen, D. L., Whalen, B. L., Kair, L. R., Vining, M., and King, B. A. (2017). Wide variation found in care of opioid-exposed newborns. Acad. Pediatr. 17, 374–380. doi:10. 1016/j.acap.2016.10.003 Bogen, D. L., Whalen, B. L., Kair, L. R., Vining, M., and King, B. A. (2017). Wide variation found in care of opioid-exposed newborns. Acad. Pediatr. 17, 374–380. doi:10. 1016/j.acap.2016.10.003 Coller, J. K., and Hutchinson, M. R. (2012). Implications of central immune signaling caused by drugs of abuse: Mechanisms, mediators and new therapeutic approaches for prediction and treatment of drug dependence. Pharmacol. Ther. 134, 219–245. doi:10. 1016/j.pharmthera.2012.01.008 Camerota, M., Davis, J. M., Dansereau, L. M., Oliveira, E. L., Padbury, J. F., and Lester, B. M. (2022). Effects of pharmacologic treatment for neonatal abstinence syndrome on dna methylation and neurobehavior: A prospective cohort study. J. Pediatr. 243, 21–26. doi:10.1016/j.jpeds.2021.12.057 Devlin, L. A., Breeze, J. L., Terrin, N., Gomez Pomar, E., Bada, H., Finnegan, L. P., et al. (2020). Conflict of interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Publisher’s note Technology advancement in the last decade has enabled more sophisticated and objective platforms for the diagnosis of NAS, in particular in predicting withdrawal severity and the need for pharmacotherapy. Using cord blood, serum samples, buccal swabs, and drops of saliva, the field progressed rapidly using SNPs, DNA methylation, GWAS, and PRS models that highlights All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher. Author contributions EY and JD: paper concept, manuscript writing and editing. NG and LJ: manuscript writing and editing. All authors contributed to the article and approved the final/submitted version. 4.3.1 Animal studies Genetic underpinning that confirms the role of inflammation in NAS may provide exciting opportunities for non- opioid replacement therapy in neonates most severely affected by the opioid epidemic. Larger sample sizes are needed to validate these findings and correlate them with changes in gene expression. References Association of a simplified Finnegan neonatal abstinence scoring tool with the need for pharmacologic treatment for neonatal abstinence syndrome. JAMA netwk. Open 3, e202275. doi:10.1001/jamanetworkopen.2020.2275 Charles, M. K., Cooper, W. O., Jansson, L. M., Dudley, J., Slaughter, J. C., and Patrick, S. W. (2017). Male sex associated with increased risk of neonatal abstinence syndrome. Hosp. Pediatr. 7, 328–334. doi:10.1542/hpeds.2016-0218 Doehring, A., Oertel, B. G., Sittl, R., and Lotsch, J. (2013). Chronic opioid use is associated with increased DNA methylation correlating with increased clinical pain. Pain 154, 15–23. doi:10.1016/j.pain.2012.06.011 Chen, M. H., Raffield, L. M., Mousas, A., Sakaue, S., Huffman, J. E., Moscati, A., et al. (2020). Trans-ethnic and ancestry-specific blood-cell genetics in 06 Frontiers in Genetics frontiersin.org Yen et al. 10.3389/fgene.2023.1140400 Lester, B. M., Tronick, E. Z., and Brazelton, T. B. (2004). The neonatal intensive care unit network neurobehavioral scale procedures. Pediatrics 113, 641–667. (no doi). doi:10.1542/peds.113.s2.641 Drummond, J. B., Simmons, M., Haroutunian, V., and Meador-Woodruff, J. H. (2012). Upregulation of cornichon transcripts in the dorsolateral prefrontal cortex in schizophrenia. Neuroreport 23, 1031–1034. doi:10.1097/WNR.0b013e32835ad229 Li, J., Li, C., Zhang, D., Shi, D., Qi, M., Feng, J., et al. (2014). SNX13 reduction mediates heart failure through degradative sorting of apoptosis repressor with caspase recruitment domain. Nat. Comm. 5, 5177. doi:10.1038/ncomms6177 Favara, M. T., Carola, D., Jensen, E., Cook, A., Genen, L., Dysart, K., et al. (2019). Maternal breast milk feeding and length of treatment in infants with neonatal abstinence syndrome. J. Perinatol. 39, 876–882. doi:10.1038/s41372-019-0374-1 Finnegan, L. P., Connaughton, J. F., Jr, Kron, R. E., and Emich, J. P. (1975). Neonatal abstinence syndrome: Assessment and management. Add. Dis. 2, 141–158. (no doi). Lowe, J. R., DiDomenico, J., Stephen, J. M., Roberts, M. H., Rodriguez, D. E., and Bakhireva, L. N. (2022). Early developmental trajectory of children with prenatal alcohol and opioid exposure. Pediatr. Res. Aug 10. doi:10.1038/s41390-022-02252-z Gaddis, N., Mathur, R., Marks, J., Zhou, L., Quach, B., Waldrop, A., et al. (2022). Multi-trait genome-wide association study of opioid addiction: OPRM1 and beyond. Sci. Rep. 12, 16873. doi:10.1038/s41598-022-21003-y Mactier, H., McLaughlin, P., Gillis, C., and Osselton, M. D. (2017). Variations in infant CYP2B6 genotype associated with the need for pharmacological treatment for neonatal abstinence syndrome in infants of methadone-maintained opioid-dependent mothers. Am. J. Perinatol. 34, 918–921. doi:10.1055/s-0037-1600917 Gelernter, J., Kranzler, H. R., Sherva, R., Koesterer, R., Almasy, L., Zhao, H., et al. (2014). References B., Rezvani, N., et al. (2008). Proinflammatory cytokines oppose opioid-induced acute and chronic analgesia. Brain Behav. Immun. 22, 1178–1189. doi:10.1016/j.bbi.2008. 05.004 Nelson, E. C., Agrawal, A., Heath, A. C., Bogdan, R., Sherva, R., Zhang, B., et al. (2016). Evidence of CNIH3 involvement in opioid dependence. Mol. Psych. 21, 608–614. doi:10.1038/mp.2015.102 Hutchinson, M. R., Northcutt, A. L., Hiranita, T., Wang, X., Lewis, S. S., Thomas, J., et al. (2012). Opioid activation of toll-like receptor 4 contributes to drug reinforcement. J. Neurosci. 32, 11187–11200. doi:10.1523/JNEUROSCI.0684-12.2012 Newville, J., Maxwell, J. R., Kitase, Y., Robinson, S., and Jantzie, L. L. (2020). Perinatal opioid exposure primes the peripheral immune system toward hyperreactivity. Front. Pediatr. 8, 272. doi:10.3389/fped.2020.00272 Jacobsen, J. H., Watkins, L. R., and Hutchinson, M. R. (2014). Discovery of a novel site of opioid action at the innate immune pattern-recognition receptor TLR4 and its role in addiction. Int. Rev. Neurobiol. 118, 129–163. doi:10.1016/B978-0-12-801284-0.00006-3 Nielsen, D. A., Utrankar, A., Reyes, J. A., Simons, D. D., and Kosten, T. R. (2012). Epigenetics of drug abuse: Predisposition or response. Pharmacogenomics 13, 1149–1160. doi:10.2217/pgs.12.94 Jansson, L. M., Dipietro, J. A., Elko, A., and Velez, M. (2010). Infant autonomic functioning and neonatal abstinence syndrome. Drug Alcohol Depend. 109, 198–204. doi:10.1016/j.drugalcdep.2010.01.004 O’Connor, A. B., Kelly, B. K., and O’Brien, L. M. (2017). Maternal and infant outcomes following third trimester exposure to marijuana in opioid dependent pregnant women maintained on buprenorphine. Drug Alcohol Depend. 180, 200–203. doi:10.1016/j.drugalcdep.2017.08.012 Jansson, L. M., Velez, M. L., McConnell, K., Spencer, N., Tuten, M., Jones, H., et al. (2017). Maternal buprenorphine treatment and infant outcome. Drug Alcohol Depend. 180, 56–61. doi:10.1016/j.drugalcdep.2017.08.001 Oei, J. L., Melhuish, E., Uebel, H., Azzam, N., Breen, C., Burns, L., et al. (2017). Neonatal abstinence syndrome and high school performance. Pediatrics 139, e20162651. doi:10.1542/peds.2016-2651 Jantzie, L. L., Maxwell, J. R., Newville, J. C., Yellowhair, T. R., Kitase, Y., Madurai, N., et al. (2020). Prenatal opioid exposure: The next neonatal neuroinflammatory disease. Brain Behav. Immun. 84, 45–58. doi:10.1016/j.bbi.2019.11.007 Oei, J. L., Xu, H. X., Abdel-Latif, M. E., Vunnam, K., Al-Amry, A., Clews, S., et al. (2012). Dopamine D2 receptor gene polymorphisms in newborn infants of drug-using women. Arch. Dis. Child. Fetal Neonatal Ed. 97, F193–F198. doi:10.1136/archdischild-2011-300235 Jilani, S. M., Jones, H. E., and Davis, J. M. (2022). Implementation of a standardized clinical definition of opioid withdrawal in the neonate: Challenges and opportunities. JAMA 327, 1643–1644. doi:10.1001/jama.2022.5406 Polimanti, R., Walters, R. K., Johnson, E. References Genome-wide association study of opioid dependence: Multiple associations mapped to calcium and potassium pathways. Biol. Psych. 76, 66–74. doi:10.1016/j. biopsych.2013.08.034 Madurai, N. K., Kitase, Y., Hamimi, S., Kirk, S. E., Sevensky, R., Ramachandra, S., et al. (2022). Methadone alters the peripheral inflammatory and central immune landscape following prenatal exposure in rats. Adv. Drug Alcohol Res. 2, 10792. doi:10.3389/adar. 2022.10792 Goldman, D., Oroszi, G., and Ducci, F. (2005). The genetics of addictions: Uncovering the genes. Nat. Rev. Genet. 6, 521–532. doi:10.1038/nrg1635 Mahnke, A. H., Roberts, M. H., Leeman, L., Ma, X., Bakhireva, L. N., and Miranda, R. C. (2022). Prenatal opioid-exposed infant extracellular miRNA signature obtained at birth predicts severity of neonatal opioid withdrawal syndrome. Sci. Rep. 12, 5941. doi:10.1038/s41598-022-09793-7 Gomez Pomar, E., Finnegan, L. P., Devlin, L., Bada, H., Concina, V. A., Ibonia, K. T., et al. (2017). Simplification of the finnegan neonatal abstinence scoring system: Retrospective study of two institutions in the USA. BMJ Open 7, e016176. doi:10. 1136/bmjopen-2017-016176 Merhar, S. L., Parikh, N. A., Braimah, A., Poindexter, B. B., Tkach, J., and Kline-Fath, B. (2019). White matter injury and structural anomalies in infants with prenatal opioid exposure. Am. J. Neuroradiol. 40, 2161–2165. doi:10.3174/ajnr.A6282 Grossman, M. R., Lipshaw, M. J., Osborn, R. R., and Berkwitt, A. K. (2018). A novel approach to assessing infants with neonatal abstinence syndrome. Hosp. Pediatr. 8, 1–6. doi:10.1542/hpeds.2017-0128 Minozzi, S., Amato, L., Jahanfar, S., Bellisario, C., Ferri, M., and Davoli, M. (2020). Maintenance agonist treatments for opiate-dependent pregnant women. Cochrane Database Syst. Rev. 11, CD006318. doi:10.1002/14651858.CD006318.pub4 Hirai, A. H., Ko, J. Y., Owens, P. L., Stocks, C., and Patrick, S. W. (2021). Neonatal abstinence syndrome and maternal opioid-related diagnoses in the US, 2010-2017. JAMA 325, 146–155. doi:10.1001/jama.2020.24991 Monnelly, V. J., Anblagan, D., Quigley, A., Cabez, M. B., Cooper, E. S., Mactier, H., et al. (2017). Prenatal methadone exposure is associated with altered neonatal brain development. NeuroImage. Clin. 18, 9–14. doi:10.1016/j.nicl.2017.12.033 Huang, H. S., Yoon, B. J., Brooks, S., Bakal, R., Berrios, J., Larsen, R. S., et al. (2014). Snx14 regulates neuronal excitability, promotes synaptic transmission, and is imprinted in the brain of mice. PLOS. One 9, e98383. doi:10.1371/journal.pone.0098383 Munoz, M. B., and Slesinger, P. A. (2014). Sorting nexin 27 regulation of G protein- gated inwardly rectifying K⁺ channels attenuates in vivo cocaine response. Neuron 82, 659–669. doi:10.1016/j.neuron.2014.03.011 Hutchinson, M. R., Coats, B. D., Lewis, S. S., Zhang, Y., Sprunger, D. References C., McClintick, J. N., Adkins, A. E., Adkins, D. E., et al. (2020). Leveraging genome-wide data to investigate differences between opioid use vs. opioid dependence in 41,176 individuals from the Psychiatric Genomics Consortium. Mol. Psych. 25, 1673–1687. doi:10.1038/s41380-020-0677-9 Jilani, S. M., Jones, H. E., Grossman, M., Jansson, L. M., Terplan, M., Faherty, L. J., et al. (2022). Standardizing the clinical definition of opioid withdrawal in the neonate. J. Pediatr. 243, 33–39.e1. doi:10.1016/j.jpeds.2021.12.021 Jilani, S. M., Jordan, C. J., Jansson, L. M., and Davis, J. M. (2021). Definitions of neonatal abstinence syndrome in clinical studies of mothers and infants: An expert literature review. J. Perinatol. 41, 1364–1371. doi:10.1038/s41372-020-00893-8 Radhakrishnan, R., Vishnubhotla, R. V., Guckien, Z., Zhao, Y., Sokol, G. M., Haas, D. M., et al. (2022). Thalamocortical functional connectivity in infants with prenatal opioid exposure correlates with severity of neonatal opioid withdrawal syndrome. Neurorad 64, 1649–1659. doi:10.1007/s00234-022-02939-4 Kantarci, K., Morrow, M. M., and Miller, V. M. (2020). Incorporating sex as a biological variable into clinical and translational research training. J. Womens Health 29, 865–867. doi:10.1089/jwh.2019.8066 Rehni, A. K., Bhateja, P., Singh, T. G., and Singh, N. (2008). Nuclear factor-kappa-B inhibitor modulates the development of opioid dependence in a mouse model of naloxone-induced opioid withdrawal syndrome. Behav. Pharmacol. 19, 265–269. doi:10. 1097/FBP.0b013e3282febcd9 Kember, R. L., Vickers-Smith, R., Xu, H., Toikumo, S., Niarchou, M., Zhou, H., et al. (2022). Cross-ancestry meta-analysis of opioid use disorder uncovers novel loci with predominant effects in brain regions associated with addiction. Nat. Neurosci. 25, 1279–1287. doi:10.1038/s41593-022-01160-z Richardson, T. G., Sanderson, E., Palmer, T. M., Ala-Korpela, M., Ference, B. A., Davey Smith, G., et al. (2020). Evaluating the relationship between circulating lipoprotein lipids and apolipoproteins with risk of coronary heart disease: A multivariable mendelian randomisation analysis. PLoS. Med. 17, e1003062. doi:10. 1371/journal.pmed.1003062 Kendler, K. S., Jacobson, K. C., Prescott, C. A., and Neale, M. C. (2003). Specificity of genetic and environmental risk factors for use and abuse/dependence of cannabis, cocaine, hallucinogens, sedatives, stimulants, and opiates in male twins. Am. J. Psychiatry 160, 687–695. doi:10.1176/appi.ajp.160.4.687 Rifkin, R. A., Huyghe, D., Li, X., Parakala, M., Aisenberg, E., Moss, S. J., et al. (2018). GIRK currents in VTA dopamine neurons control the sensitivity of mice to cocaine- induced locomotor sensitization. Proc. Natl. Acad. Sci. USA. 115, E9479–E9488. doi:10. 1073/pnas.1807788115 Kocherlakota, P., Qian, E. C., Patel, V. C., Mandru, C., Vilar, R. E., Alpan, G., et al. (2020). Frontiers in Genetics References A new scoring system for the assessment of neonatal abstinence syndrome. Am. J. Perinatol. 37, 333–340. doi:10.1055/s-0039-3400310 Krans, E. E., Kim, J. Y., Chen, Q., Rothenberger, S. D., James, A. E., 3rd, Kelley, D., et al. (2021). Outcomes associated with the use of medications for opioid use disorder during pregnancy. Addiction 116, 3504–3514. doi:10.1111/add.15582 Ryu, J., Lee, S., Payne, B., Gorse, K., and Lafrenaye, A. (2021). Buprenorphine alters microglia and astrocytes acutely following diffuse traumatic brain injury. Sci. Rep. 11, 8620. doi:10.1038/s41598-021-88030-z 07 Frontiers in Genetics frontiersin.org Yen et al. 10.3389/fgene.2023.1140400 Sanchez-Roige, S., Fontanillas, P., Jennings, M. V., Bianchi, S. B., Huang, Y., Hatoum, A. S., et al. (2021). Genome-wide association study of problematic opioid prescription use in 132,113 23andMe research participants of European ancestry. Mol. Psych. 26, 6209–6217. doi:10.1038/s41380-021-01335-3 Wachman, E. M., Hayes, M. J., Sherva, R., Brown, M. S., Shrestha, H., Logan, B. A., et al. (2017). Association of maternal and infant variants in PNOC and COMT genes with neonatal abstinence syndrome severity. Am. J. Addict. 26, 42–49. doi:10.1111/ajad.12483 Wachman, E. M., Hayes, M. J., Shrestha, H., Nikita, F. N. U., Nolin, A., Hoyo, L., et al. (2018). Epigenetic variation in OPRM1 gene in opioid-exposed mother-infant dyads. Genes Brain Behav. 17, e12476. doi:10.1111/gbb.12476 Sawaya, B. E., Deshmane, S. L., Mukerjee, R., Fan, S., and Khalili, K. (2009). TNF alpha production in morphine-treated human neural cells is NF-kappaB-dependent. J. Neuroimmune. Pharmacol. 4, 140–149. doi:10.1007/s11481-008-9137-z Wachman, E. M., Wang, A., Isley, B. C., Boateng, J., Beierle, J. A., Hansbury, A., et al. (2020). Placental OPRM1 DNA methylation and associations with neonatal opioid withdrawal syndrome, a pilot study. Exp. Med. 1, 124–135. doi:10.37349/emed.2020.00009 Seney, M. L., Kim, S. M., Glausier, J. R., Hildebrand, M. A., Xue, X., Zong, W., et al. (2021). Transcriptional alterations in dorsolateral prefrontal cortex and nucleus accumbens implicate neuroinflammation and synaptic remodeling in opioid use disorder. Biol. Psych. 90, 550–562. doi:10.1016/j.biopsych.2021.06.007 Wang, X., Douglas, S. D., Commons, K. G., Pleasure, D. E., Lai, J., Ho, C., et al. (2004). A non-peptide substance P antagonist (CP-96,345) inhibits morphine-induced NF- kappa B promoter activation in human NT2-N neurons. J. Neurosci. Res. 75, 544–553. doi:10.1002/jnr.10873 Sharifi, S., Caracciolo, G., Pozzi, D., Digiacomo, L., Swann, J., Daldrup-Link, H. E., et al. (2021). The role of sex as a biological variable in the efficacy and toxicity of therapeutic nanomedicine. Adv. Drug Deliv. Rev. 174, 337–347. doi:10.1016/j.addr.2021. 04.028 Wang, X., Loram, L. References C., Ramos, K., de Jesus, A. J., Thomas, J., Cheng, K., et al. (2012). Morphine activates neuroinflammation in a manner parallel to endotoxin. Proc. Natl. Acad. Sci. USA. 109, 6325–6330. doi:10.1073/pnas.1200130109 Sikka, P., Madan, N., and Yen, E. (2022). Early white matter tract changes in neonates with prenatal opioid exposure: A pilot study. J. Perinatol. Jun 18. doi:10.1038/s41372- 022-01427-0 Watkins, L. R., Hutchinson, M. R., Rice, K. C., and Maier, S. F. (2009). The "toll" of opioid-induced glial activation: Improving the clinical efficacy of opioids by targeting glia. Trends Pharmacol. Sci. 30, 581–591. doi:10.1016/j.tips.2009.08.002 Sirnes, E., Oltedal, L., Bartsch, H., Eide, G. E., Elgen, I. B., and Aukland, S. M. (2017). Brain morphology in school-aged children with prenatal opioid exposure: A structural MRI study. Early Hum. Dev. 106, 33–39. doi:10.1016/j.earlhumdev.2017.01.009 Willer, C. J., Schmidt, E. M., Sengupta, S., Peloso, G. M., Gustafsson, S., Kanoni, S., et al. (2013). Discovery and refinement of loci associated with lipid levels. Nat. Gen. 45, 1274–1283. doi:10.1038/ng.2797 Song, W., Kossowsky, J., Torous, J., Chen, C. Y., Huang, H., Mukamal, K. J., et al. (2020). Genome-wide association analysis of opioid use disorder: A novel approach using clinical data. Drug Alcohol Depend. 217, 108276. doi:10.1016/j.drugalcdep.2020. 108276 Winkelman, T. N. A., Villapiano, N., Kozhimannil, K. B., Davis, M. M., and Patrick, S. W. (2018). Incidence and costs of neonatal abstinence syndrome among infants with medicaid: 2004-2014. Pediatrics 141, e20173520. doi:10.1542/peds.2017-3520 Subedi, L., Huang, H., Pant, A., Westgate, P. M., Bada, H. S., Bauer, J. A., et al. (2017). Plasma brain-derived neurotrophic factor levels in newborn infants with neonatal abstinence syndrome. Front. Pediatr. 5, 238. doi:10.3389/fped.2017.00238 Yen, E., Kaneko-Tarui, T., Ruthazer, R., Harvey-Wilkes, K., Hassaneen, M., and Maron, J. L. (2019). Sex-dependent gene expression in infants with neonatal opioid withdrawal syndrome. J. Pediatr. 214, 60–65. doi:10.1016/j.jpeds.2019.07.032 Timpson, W., Killoran, C., Maranda, L., Picarillo, A., and Bloch-Salisbury, E. (2018). A quality improvement initiative to increase scoring consistency and accuracy of the finnegan tool: Challenges in obtaining reliable assessments of drug withdrawal in neonatal abstinence syndrome. Adv. Neonatal Care 18, 70–78. doi:10.1097/ANC. 0000000000000441 Yen, E., Madan, N., Tarui, T., Kaneko-Tarui, T., Breeze, J. L., Davis, J. M., et al. (2022). Sex-specific inflammatory and white matter effects of prenatal opioid exposure: A pilot study. Pediatr. Res. Oct. 24. doi:10.1038/s41390-022-02357-5 Yen, E., Murphy, H. J., Friedman, H., Lucke, A. M., and Rodday, A. M. (2021). Neonatal abstinence syndrome practice variations across pediatric subspecialty. References J. Perinatol. 41, 1512–1514. doi:10.1038/s41372-020-00831-8 Unger, A., Jagsch, R., Bäwert, A., Winklbaur, B., Rohrmeister, K., Martin, P. R., et al. (2011). Are male neonates more vulnerable to neonatal abstinence syndrome than female neonates? Gend. Med. 8, 355–364. doi:10.1016/j.genm.2011.10.001 Yeoh, S. L., Eastwood, J., Wright, I. M., Morton, R., Melhuish, E., Ward, M., et al. (2019). Cognitive and motor outcomes of children with prenatal opioid exposure: A systematic review and meta-analysis. JAMA. netwk. Open 2, e197025. doi:10.1001/ jamanetworkopen.2019.7025 Vasan, V., Kitase, Y., Newville, J. C., Robinson, S., Gerner, G., Burton, V. J., et al. (2021). Neonatal opioid exposure: Public health crisis and novel neuroinflammatory disease. Neural. Regen. Res. 16, 430–432. doi:10.4103/1673-5374.293136 Yuan, Q., Rubic, M., Seah, J., Rae, C., Wright, I. M., Kaltenbach, K., et al. (2014). Do maternal opioids reduce neonatal regional brain volumes? A pilot study. J. Perinatol. 34, 909–913. doi:10.1038/jp.2014.111 Vuckovic, D., Bao, E. L., Akbari, P., Lareau, C. A., Mousas, A., Jiang, T., et al. (2020). The polygenic and monogenic basis of blood traits and diseases. Cell 182, 1214–1231.e11. doi:10.1016/j.cell.2020.08.008 Zhang, H., Largent-Milnes, T. M., and Vanderah, T. W. (2020). Glial neuroimmune signaling in opioid reward. Brain Res. Bull. 155, 102–111. doi:10.1016/j.brainresbull. 2019.11.012 Wachman, E. M., and Farrer, L. A. (2019). The genetics and epigenetics of neonatal abstinence syndrome. Semin. Fetal Neonatal Med. 24, 105–110. doi:10.1016/j.siny.2019. 01.002 Zhang, P., Yang, M., Chen, C., Liu, L., Wei, X., and Zeng, S. (2020). Toll-like receptor 4 (TLR4)/opioid receptor pathway crosstalk and impact on opioid analgesia, immune function, and gastrointestinal motility. Front. Immunol. 11, 1455. doi:10.3389/fimmu. 2020.01455 Wachman, E. M., Hayes, M. J., Brown, M. S., Paul, J., Harvey-Wilkes, K., Terrin, N., et al. (2013). Association of OPRM1 and COMT single-nucleotide polymorphisms with hospital length of stay and treatment of neonatal abstinence syndrome. JAMA 309, 1821–1827. doi:10.1001/jama.2013.3411 Zhou, H., Rentsch, C. T., Cheng, Z., Kember, R. L., Nunez, Y. Z., Sherva, R. M., et al. (2020). Association of OPRM1 functional coding variant with opioid use disorder: A genome-wide association study. JAMA. Psych. 77, 1072–1080. doi:10.1001/jamapsychiatry.2020.1206 Wachman, E. M., Hayes, M. J., Lester, B. M., Terrin, N., Brown, M. S., Nielsen, D. A., et al. (2014). Epigenetic variation in the mu-opioid receptor gene in infants with neonatal abstinence syndrome. J. Pediatr. 165, 472–478. doi:10.1016/j.jpeds.2014.05.040 Zucker, I., and Prendergast, B. J. (2020). Sex differences in pharmacokinetics predict adverse drug reactions in women. Biol. Sex. Differ. 11, 32. doi:10.1186/s13293-020- 00308-5 Wachman, E. Wachman, E. M., Hayes, M. J., Sherva, R., Brown, M. S., Davis, J. M., Farrer, L. A., et al. (2015). Variations in opioid receptor genes in neonatal abstinence syndrom. Drug Alcohol Depend. 155, 253–259. doi:10.1016/j.drugalcdep.2015.07.001 References M., Hayes, M. J., Sherva, R., Brown, M. S., Davis, J. M., Farrer, L. A., et al. (2015). Variations in opioid receptor genes in neonatal abstinence syndrom. Drug Alcohol Depend. 155, 253–259. doi:10.1016/j.drugalcdep.2015.07.001 08 Frontiers in Genetics 08 frontiersin.org
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Assessing children's cognitive flexibility with the Shape Trail Test
PloS one
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Evaluation of susceptibility to injuries resulting from falls of children with visual impairment
European Journal of Adapted Physical Activity
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EVALUATION OF SUSCEPTIBILITY TO INJURIES RESULTING FROM FALLS OF CHILDREN WITH VISUAL IMPAIRMENT Dariusz Boguszewski1, Martyna Zabłocka2, Jakub Grzegorz Adamczyk1,3 Katarzyna Boguszewska4, Dariusz Białoszewski1 1. Rehabilitation Department. Medical University of Warsaw, Poland 2. Students Science Club of Physiotherapy. Medical University of Warsaw, Poland 3. Theory of Sport Department. University of Physical Education in Warsaw, Poland 4. Piotr Skarga Catholic Educational Center in Warsaw, Poland The main purpose of the study was the analysis of safe falling skills visually impaired children. An attempt has been made to examine the relationship between ability of safe falls and occurrence injuries from the effect of falls. 103 children (10-16 years old) were in research and control groups. In the research group (Group I) was 39 visually impaired pupils, in control group (Group II) 64 sighted in a proper manner. Test of Susceptibility to Injury During the Falls (TSIDF) by Kalina and interview directed to determine the number and frequency of falls and their consequences were used as a research tools. There were 578 falls and 176 injuries resulting from them (7.33 falls per person in Group I and 4.96 in Group II; 2.51 injuries per person in Group I and 1.18 in Group II). Visually impaired people made more mistakes in test (TSIDF) than their non-disabled peers (p=0.007). This may prove that a high susceptibility to injury of the children from the research group (p=0.001). However visual impairment people had more injuries after the falls. Study confirmed positive effect of physical activity on the level of safe falls skills. The ability to fall down in a safe way in children suffering from visual impairment is more improperly developed when compared it to healthy children. Physical activity and especially exercises of safe falls skills can be important element of prevention of falls. European Journal of Adapted Physical Activity, 6(1), 7-16 © European Federation of Adapted Physical Activity, 2013 European Journal of Adapted Physical Activity, 6(1), 7-16 © European Federation of Adapted Physical Activity, 2013 INTRODUCTION large extent they are the primary causes of serious injuries, or even death. It is therefore vital to create a set of principles helping the avoid situations which may potentially result in falls and to implement a prophylactic study of body movements which could minimize the harmful effects of collapsing to the ground or hitting a vertical obstacle (Kalina, Kalina & Klukowski, 1998). Sense organs are our “primary channels” in receiving stimuli from the environment. Sight is seemingly the most important sense for every human being. However, it is particularly important for children who learn the world through knowing the objects and phenomena surrounding it (Gruszczyński & Rutkowska, 2003). Therefore, considerable impairment or complete loss of sight has great impact on the child’s cognitive abilities, even though it does not change the child’s potential developmental possibilities (Rutkowska, Morgulec- Adamowicz, Skowroński, 2009). Scientific research has proven that a falling persons have not the skills to secure themselves. This was the reason to develop the safe fall theory (Czerwiński et al., 2006; Kalina et al., 2003, 2011). The safe fall theory states the measures to be taken in order to completely avoid or mitigate the effects of injuries resulting from threatening situations. It should be noted that specialists in dangerous professions, affecting the falls and injuries (such as stuntmen, athletes or soldiers of the special units) the ability to the safe falling down use in everyday real life. Hence, the people who tend to fall down and suffer from Similarly to people undergoing limb amputation, suffering from osteoporosis or musculoskeletal system conditions, children suffering from visual impairment (VI) are a group which is particularly prone to injuries resulting from falls (Kalina, Kalina & Klukowski, 1998). In this case, falls are considered to be social problems, since to a EUJAPA, Vol. 6, No. 1 7 Susceptibility to injuries of children with VI Boguszewski at al. 2. Determine the relationship between physical activity and susceptibility to injury during falls. 2. Determine the relationship between physical activity and susceptibility to injury during falls. severe injuries resulting from the falls (occurring in the street, at home, on stairs, etc.) are usually those who do not possess the ability or knowledge of falling down safely (Kalina, Kalina & Klukowski, 1998; Boguszewski & Kerbaum, 2011). METHODS , ) Therefore, in order to reduce the risk of suffering from post-fall injuries, one should develop the habit of falling down in a safe way. Motor coordination, the ability to protect one’s head, the ability to loosen one’s muscles all contribute to preventing body injuries during falls. Such elements could reduce the risk entailed by falls or resulting personal injuries (Kalina et al., 2003, 2011; Boguszewski & Kerbaum, 2011). People with visual impairment are particularly prone to injuries resulting from falls (Coleman et al.; 2004, Black & Wood, 2005; Patino et al., 2010; Manduchi & Kurniawan, 2011). Therefore, a special preventive program dedicated entirely to the visually impaired could reduce the risk of life-threatening injuries. Similar solutions have been used with positive results among different groups (e.g. the elderly) (Rubenstein, et al., 2000; Barnett, et al., 2003; Li, et al., 2005; Rose, 2008; Groen et al., 2010). Participants p The research covered a group of 103 children between the age of 10 and 16 (including 43 girls and 60 boys). The children participating in the research were divided into two groups – the researched group (n=39) comprised children with visual impairment (VI) – Group I, and the control group (n=64) of children without visual impairment – Group II (table 1). The average age of children participating in the research was 13.1. There were not significant differences between groups in age, body mass and height. The WHO classification was applied in reference to the researched group. According to the WHO classification, the children were diagnosed with visual impairment – best corrected visual acuity was from 0.3 to 0.005 in the better eye. Additionally, only children without any other dysfunctions (e.g. neurological dysfunctions) which could potentially inhibit their motor abilities have been qualified for the research. The aim of the study was the diagnosis of safe falling skills visually impaired children and their healthy peers. An attempt has been made to: The research was carried out in the 2010/2011 school year in the Educational Center for Children with Visual Impairment in Warsaw (Group I) and in the public school in Warsaw (Group II). 1. Establish the relationship between the skills to safely falling down and the occurrence of injuries resulting from falls. TABLE 1 TABLE 1 Characteristics of research groups (mean value ± standard deviation) groups gender n age [years] body mass [kg] height [cm] physically active [n] Group I (visual impaired) girls 15 12.4 ± 1.5 45.8 ± 9.9 154.9 ± 10.3 5 boys 24 13.8 ± 2.1 60.2 ± 12.1 168.5 ± 11.1 13 Group II (control) girls 28 12.4 ± 2.1 46.6 ± 10.3 156.1 ± 8.9 14 boys 36 13.4 ± 2.1 54.4 ± 12.1 163.6 ± 12.5 24 Characteristics of research groups (mean value ± standard deviation) EUJAPA, Vol. 6, No. 1 EUJAPA, Vol. 6, No. 1 8 8 Susceptibility to injuries of children with VI Boguszewski at al. Test of Susceptibility to Injury During the Falls Children from Group I got significantly higher results in the Test of Susceptibility to Injury During the Falls (p=0.007), which means that they committed a larger number of errors performing the motor activities. The biggest disparities (p=0.004) occurred in the last activity, which was theoretically the most difficult one. The majority of errors committed by children from both groups concerned applying improper support with the hands. The biggest disparities between the two groups were recorded in this respect. The smallest disparities (statistically insignificant) were recorded with respect to protection of the head (fig. 1 and 2). The results of the Test of Susceptibility to Injury During the Falls acquired by boys and girls were quite similar. y y g In Group I almost 82% of the children were characterized by high or very high proneness to injuries resulting from falls. In comparison, nearly 67% of children from the control group were similarly classified. In opposition to non- active children, physically active children committed fewer errors while performing the assigned motor activities, although significant disparities (p=0.000) were recorded only in Group II. Only 5 (9%) of physically active children acquired a result standing for very high proneness to post-fall injuries. 17 (37%) non-active children acquired the same result. 23 (41%) of physically active children and 5 (11%) non-active children were characterized by low or medium proneness to post-fall injuries (tab. 2). The research was accompanied by an investigation of the types of falls (number of falls, circumstances of occurrence), the injuries incurred during falls (with the exception of sports-related injuries), and the types of physical activities performed (type, frequency). Information from the last three years was included in the investigation. MEASURES AND PROCEDURES minimum three times a week outside their school classes were classified as active (table 1). The second division into sub-groups referred to the age of the researched children – younger (10-13 years old) and older children (14-16 years old). One of the tools used in the research was Kalina’s Test of Susceptibility to Injury During the Falls (TSIDF). Reliability of the test was confirmed by the author (for groups of healthy young people) (Kalina et al., 2011). The test was based on performing three motor activities as fast as possible. The first motor activity was proceeding from the basic position to lying down on the back (on a mattress). In the second motor activity, apart from the above mentioned process, the child had to hold a small bag between the chin and the sternum and to clap its knees. In the third motor activity, apart from the above mentioned, basic movement, the child was to make a leap before proceeding to lying down on the back. However, children were not specifically instructed how to make the exercises. Each attempt was evaluated for errors – deviations from the correct mode of safe falling. The results were entered to the observation sheet. The sum of errors for particular body parts (head, legs, hips, arms) collected from all three activities serves as the Susceptibility to Injury During the Falls Index (SIDF). The higher the result, the higher was the proneness to injuries. The sum of points collected after all three activities serves as the Susceptibility to Injury During the Falls Index, in which 0 points stands for low proneness, 1 to 3 points stand for medium proneness, 4 to 9 points stand for high proneness, and 10 to 14 points stand for very high proneness (Kalina et al., 2011). All children were assessed by two specialists in physical education and physiotherapy (specializing in teaching safe falling down). Standard statistical tools, such as arithmetic mean and standard deviation, were applied in the research. The relations between particular variables (number of injuries and results of SIDF Test) were established with the Pearson’s correlation coefficient. The differences between particular data were calculated with independent t-test. The minimal significance level was established at p<0.05. Data Analysis For comparative purposes, two additional divisions into sub-groups have been isolated as part of the above mentioned groups. In the first division into sub-groups, undertaking or non- undertaking regular physical activity was the essential criterion. Children who participated in organized sports or recreational classes EUJAPA, Vol. 6, No. 1 9 9 Susceptibility to injuries of children with VI Boguszewski at al. FIGURE 2 Results of Test of Susceptibility to Injury During the Falls among the boys 1,63 1,75 2,83 1,00 1,11 1,44 1,61 1,17 0 0,5 1 1,5 2 2,5 3 lower limbs hips upper limbs head GROUP I GROUP II NS NS p=0,029 p=0,011 [SIDF] FIGURE 1 FIGURE 1 Results of Test of Susceptibility to Injury During the Falls among the girls FIGURE 2 Results of Test of Susceptibility to Injury During the Falls among the boys TABLE 2 Level of susceptibility to injury during a fall of girls and boys groups gender susceptibility to injury during a fall low average high very high Group I active girls 0 0 3 2 boys 1 3 6 3 non-active girls 0 2 4 4 boys 0 1 6 4 Group II active girls 1 4 9 0 boys 1 13 10 0 ti girls 0 1 10 3 1,80 1,60 3,13 2,00 1,32 1,14 1,93 1,57 0 0,5 1 1,5 2 2,5 3 3,5 lower limbs hips upper limbs head GROUP I GROUP II p=0,044 NS p=0,038 NS [SIDF] 1,63 1,75 2,83 1,00 1,11 1,44 1,61 1,17 0 0,5 1 1,5 2 2,5 3 lower limbs hips upper limbs head GROUP I GROUP II NS NS p=0,029 p=0,011 [SIDF] FIGURE 1 Results of Test of Susceptibility to Injury During the Falls among the girls FIGURE 2 1,80 1,60 3,13 2,00 1,32 1,14 1,93 1,57 0 0,5 1 1,5 2 2,5 3 3,5 lower limbs hips upper limbs head GROUP I GROUP II p=0,044 NS p=0,038 NS [SIDF] Results of Test of Susceptibility to Injury During the Falls among the girls Falls and injuries The majority of children participating in the research (88%) claimed to have fallen at least once in the last three years, 35 (90%) children from group one and 57 (89%) children from group two fell down at least once. In total, the research children declared 578 falls and 176 personal injuries (resulting from the falls). The average number of falls per person in Group I was 7.33, and 4.96 in Group II. Boys tended to fall down more often (in average 7.58 – Group I and 5.64 – Group II) than girls (correspondingly 6.93 and 4.11). The average number of personal injuries was 2.51 with respect to handicapped children and 1.18 with respect to healthy children. Girls tended to suffer from personal injuries more often (in average 2.97 – Group I and 1.21 – Group II) than boys (correspondingly 2.41 and 1.16). Comparison of the number of falls and injuries of children physically active and inactive, and younger and older children Children with visual impairment staying physically active usually suffered from injuries of the lower limbs (in average 1.2 per person) and of the upper limbs (in average – 1 per person). On the other hand, physically active children from Group II usually suffered from injuries of the lower limbs (0.5). Injuries of the head and spine area were rather rare (0.28 – Group I, 0.08 – Group II). Non-active children indicated more injuries of all aforementioned body parts (head and spine: in average 0.43 – Group I and 0.19 – Group II; upper limbs: 0.91 and 0.61; lower limbs: 1.38 and 0.81). Physically active children rarely suffered from post-fall injuries (in average 2.39 per person – Group I and 0.89 – Group II) in comparison to non-active children (correspondingly 2.62 and 1.62). Injuries incurred usually concerned the lower limbs (in average 1.06 per person in reference to non- active children and 0.62 in reference to active children). ) Younger children (10-13 years old) suffered from falls and resulting injuries slightly more often than older children. No significant disparities in the number of falls and resulting injuries were recorded between Groups I and Boguszewski at al. Younger children (between the age of 10- 13) from both groups acquired a higher result in the Test of Susceptibility to Injury During the Falls, which means that they committed more errors. Bigger disparities concerned boys rather than girls. When it comes to the sub- group of younger children, children with visual impairment committed more errors in all of three assigned motor activities. However, considerable disparities were recorded only in the “arm” category in girls (p=0.047) and in the “head” category in boys (p=0.014). When it comes to the sub-group of older children (14- 16 years old), the disparity between handicapped and healthy children were bigger. In particular, boys from Group I displayed a significantly lower level of motor skills in comparison to their peers from Group II. Statistically significant differences were recorded in the “legs” category (p=0.000), the “arms” category (p=0.003) and the “head” category (p=0.016). Visually impaired children suffered from more injuries resulting from collapsing to the ground (p=0.001). The most common injuries in group one were wounds and abrasions (in average – 1.15 per person), however, in group two – these were mainly contusions (0.67). The most severe injuries, such as bone fractures usually occurred in children suffering from visual impairment (in average 0.33 – Group I, 0.06 – Group II). Both physically active and non-active children suffered primarily from minor injuries – wounds, abrasions and contusions (slightly more incidents in the non-active group). Bone fractures occurred rarely in both groups. Still the number of fractures was bigger in the non- active group. The average number personal injuries was nearly identical with girls (1.72) and boys (1.67). When it comes to children with visual impairment, the injuries were generally located around the lower limb area (in average 1.15 per person) and, slightly rarer, in the upper limb area (1.07). Injuries of the head area or of the spinal area were rather rare (0.36), since these are the body parts which should be particularly protected during a fall. Similar tendency was recorded in the control group, where the majority of injuries concerned the lower limb area (0.62), and the upper limb area (0.41). Head and spine injuries were rare (0.12), even rarer than in the case of the first group (fig. 3 and 4). Level of susceptibility to injury during a fall of girls and boys groups gender susceptibility to injury during a fall low average high very high Group I active girls 0 0 3 2 boys 1 3 6 3 non-active girls 0 2 4 4 boys 0 1 6 4 Group II active girls 1 4 9 0 boys 1 13 10 0 non-active girls 0 1 10 3 boys 0 1 5 6 10 EUJAPA, Vol. 6, No. 1 EUJAPA, Vol. 6, No. 1 10 The type and location of injuries EUJAPA, Vol. 6, No. 1 11 Susceptibility to injuries of children with VI Boguszewski at al. Visually impaired girls suffered from post-fall injuries more often (p=0.048), whereas in the case of boys, the result was close to the significance level (p=0.077) (tab. 4). Visually impaired girls suffered from post-fall injuries more often (p=0.048), whereas in the case of boys, the result was close to the significance level (p=0.077) (tab. 4). II. The above mentioned events referred to children suffering from visual impairment only (tab. 3). When it comes to older children (14- 16 years old), the disparities (particularly in the number of injuries) were more significant. TABLE 4 F indicator value, the number of falls and injuries among the children aged 14-16 years SIDF indicator value, the number of falls and injuries among the children aged 14-16 years Girls Boys Group I (n=7) Group II (n=8) p Group I (n=17) Group II (n=17) p mean value SD mean value SD mean value SD mean value SD SIDF 6.25 4.35 3.75 3.54 0.364 7.41 3.82 2.76 2.31 0.000 falls 12.5 8.69 5.5 4.84 0.209 9.12 7.86 5.12 3.87 0.072 injuries 2.5 1.29 0.5 0.53 0.048 2.29 2.66 1 1.06 0.077 & Ocetkiewicz, 2003; Czerwiński et al., 2008). FIGURE 3 FIGURE 3 Number of injuries resulting from the fall of the girls FIGURE 4 Number of injuries resulting from the fall of the boys Children who acquired lower results in the Test of Susceptibility to Injury During the Falls declared to have suffered from post-fall injuries more often. The correlation between the Test result and the number of injuries was r=0.58 (p=0.000). To a great extent, t tendency concerned children with vis impairment (r=0.6 p=0.000) rather than heal children (r=0.53 p=0.000). 1,33 0,80 0,60 0,68 0,32 0,18 0 0,2 0,4 0,6 0,8 1 1,2 1,4 lower limb upper limb head, spine GROUP I GROUP II p=0,041 p=0,049 NS [n/person] 1,04 1,25 0,21 0,58 0,47 0,08 0 0,2 0,4 0,6 0,8 1 1,2 1,4 lower limb upper limb head, spine GROUP I GROUP II NS p=0,044 NS [n/person] Number of injuries resulting from the fall of the girls 1,33 0,80 0,60 0,68 0,32 0,18 0 0,2 0,4 0,6 0,8 1 1,2 1,4 lower limb upper limb head, spine GROUP I GROUP II p=0,041 p=0,049 NS [n/person] Number of injuries resulting from the fall of the girls FIGURE 4 FIGURE 4 Number of injuries resulting from the fall of the boys 1,04 1,25 0,21 0,58 0,47 0,08 0 0,2 0,4 0,6 0,8 1 1,2 1,4 lower limb upper limb head, spine GROUP I GROUP II NS p=0,044 NS [n/person] Children who acquired lower results in the Test of Susceptibility to Injury During the Falls declared to have suffered from post-fall injuries more often. The correlation between the Test result and the number of injuries was Children who acquired lower results in the Test of Susceptibility to Injury During the Falls declared to have suffered from post-fall injuries more often. The correlation between the Test result and the number of injuries was r=0.58 (p=0.000). To a great extent, this tendency concerned children with visual impairment (r=0.6 p=0.000) rather than healthy children (r=0.53 p=0.000). r=0.58 (p=0.000). To a great extent, this tendency concerned children with visual impairment (r=0.6 p=0.000) rather than healthy children (r=0.53 p=0.000). EUJAPA, Vol. 6, No. 1 12 Susceptibility to injuries of children with VI Boguszewski at al. TABLE 3 TABLE 3 SIDF indicator value, the number of falls and injuries among the children aged 10-13 years TABLE 3 SIDF indicator value, the number of falls and injuries among the children aged 10-13 years Girls Boys Group I (n=11) Group II (n=20) p Group I (n=4) Group II (n=19) p mean value SD mean value SD mean value SD mean value SD SIDF 8.81 3.97 6.85 2.43 0.156 6.43 2.28 7.73 3.19 0.332 falls 5.09 3.27 3.55 3.3 0.225 3.86 3.02 5.21 3.49 0.351 injuries 2.73 2.05 1.5 0.83 0.082 2.71 2.29 1.32 1.11 0.164 TABLE 4 SIDF indicator value, the number of falls and injuries among the children aged 14-16 years Girls Boys Group I (n=7) Group II (n=8) p Group I (n=17) Group II (n=17) p mean value SD mean value SD mean value SD mean value SD SIDF 6.25 4.35 3.75 3.54 0.364 7.41 3.82 2.76 2.31 0.000 falls 12.5 8.69 5.5 4.84 0.209 9.12 7.86 5.12 3.87 0.072 injuries 2.5 1.29 0.5 0.53 0.048 2.29 2.66 1 1.06 0.077 DISCUSSION People of all ages have and will fall down. This is considered one of the major problems of senior age, and the main cause of injuries in seniors. Nearly 20% of all causes of death of people over the age of 65 include post-fall injuries (Skalska, Walczewska & Ocetkiewicz, & Ocetkiewicz, 2003; Czerwiński et al., 2008). People who underwent lower limb amputation, people suffering from diabetes, people using wheelchairs, seniors, people suffering from osteoporosis, as well as people suffering from visual impairment are particularly prone to falling (Capella-McDonnal, 2007; Patino et al., 2010; Manduchi & Kurniawan, 2011; Odom, SIDF indicator value, the number of falls and injuries among the children aged 10-13 years Girls Boys Group I (n=11) Group II (n=20) p Group I (n=4) Group II (n=19) p mean value SD mean value SD mean value SD mean value SD SIDF 8.81 3.97 6.85 2.43 0.156 6.43 2.28 7.73 3.19 0.332 falls 5.09 3.27 3.55 3.3 0.225 3.86 3.02 5.21 3.49 0.351 injuries 2.73 2.05 1.5 0.83 0.082 2.71 2.29 1.32 1.11 0.164 SIDF indicator value, the number of falls and injuries among the children aged 10-13 years F indicator value, the number of falls and injuries among the children aged 10-13 years DISCUSSION , ; , ) People who underwent lower limb amputation, people suffering from diabetes, people using wheelchairs, seniors, people suffering from osteoporosis, as well as people suffering from visual impairment are particularly prone to falling (Capella-McDonnal, 2007; Patino et al., 2010; Manduchi & Kurniawan, 2011; Odom, Odom, Leys, 2011). People of all ages have and will fall down. This is considered one of the major problems of senior age, and the main cause of injuries in seniors. Nearly 20% of all causes of death of people over the age of 65 include post-fall injuries (Skalska, Walczewska & Ocetkiewicz, 2003; Bączkowicz, Szczegielniak & Proszkowiec, 2008; Czerwiński et al., 2008). The causes of falls include internal conditions (illness, senile conditions) and external conditions (environmental, situational conditions). Preventing falls is thus an essential, but expensive issue. Research clearly shows that it is possible to lower the risk of falls even by 40% if the patient is treated by a multidisciplinary team (Skalska, Walczewska Evaluations of proneness to injuries resulting from falls in people with visual impairment have been carried out very rarely. People suffering from complete blindness or partial visual impairment are examined primarily for their physical fitness and posture (Bolach et al., 2007, Bolach, Bolach & Józefowski, 2009; Patel et al., 2009; Jessup, Cornel & Bundy, 2010; Rutkowska, EUJAPA, Vol. 6, No. 1 13 Susceptibility to injuries of children with VI Boguszewski at al. Bednarczuk, Skowroński, 2010). The occurrence of injuries resulting from falls is generally evaluated in seniors or healthy children, without comparing their results with the results acquired by children suffering from various conditions and dysfunctions (Tinetti & Williams, 1997; Kalina, Kalina & Klukowski, 1998; Czerwiński et al. 2008). Bednarczuk, Skowroński, 2010). The occurrence of injuries resulting from falls is generally evaluated in seniors or healthy children, without comparing their results with the results acquired by children suffering from various conditions and dysfunctions (Tinetti & Williams, 1997; Kalina, Kalina & Klukowski, 1998; Czerwiński et al. 2008). of proneness to personal injuries resulting from falls after having undergone intense safe- falling training, for instance in the form of program based on the propaedeutics of combat sports (Kalina et al., 2008; Gąsienica-Walczak et al., 2010; Boguszewski & Kerbaum, 2011), in order to claim to what extent the abilities taught are acquired by the trainees and how they could be applied in everyday life. CONCLUSIONS 1. The ability to fall down in a safe way in children suffering from visual impairment is more improperly developed when compared it to healthy children. Therefore, children with visual impairment may be more prone to personal injuries resulting from situations ending with falls. 2. Visually impaired children often have injuries from falls. This may be a result of a lower level of special coordination and inability to safe falling. The risk of falls and injuries that may occur can be minimized by learning specific skills (safe fall). Epidemiological data indicates that the majority of effects of falls in the form of fractures were recorded in two age groups: from 8 to 15 and above 60 (Czerwiński, Borowy & Jasiak, 2006). However, there is no statistical data defining the types and locations of injuries in people suffering from visual impairment (Kalina, Kalina & Klukowski, 1998). The results of this research allow us to claim that children between the age of 10 and 16 may be prone to personal injuries resulting from falls, which is proven by high results of the Test of Susceptibility to Injury During the Falls carried out. 3. The results of research prove the beneficial effect of physical activity on the occurrence of defensive reflexes, protecting the body from being harmed. Children spending their time actively suffered from fewer injuries after falling down than non-active children. DISCUSSION Physical fitness may serve as the basis for fall prevention, since it contributes to improving bone structure, influences the operation of the respiratory and circulatory systems, and results in increasing the muscular structure as well as the scope of movement of the joints (Tinetti & Williams, 1997; Boguszewski & Kerbaum, 2011). Physical fitness helps us to properly position our bodies in order to fall in a safe manner. Therefore, thanks to physical fitness, we not only become fitter, but we also become less liable to fall down randomly – hence we are less prone to injuries resulting from a fall (Tinetti & Williams, 1997; Skalska, Walczewska & Ocetkiewicz, 2003; Skelton, Kennedy & Rutherford, 2004). REFERENCES Bączkowicz, D., Szczegielniak, J. & Proszkowiec, M. (2008). Relations between postural stability, gait and falls in elderly persons – preliminary report. Ortopedia Traumatologia Rehabilitacja, 10(5), 476- 480. The natural direction for further research would be to expand the groups of people covered and to include the cause of the loss of sight as a valid criterion. Due to frequent occurrence of posture defects, it would be justified to include an evaluation of postures in researched groups (Bolach et al., 2007; Bolach, Bolach & Józefowski, 2009). Additional elements to be diagnosed may be the ability to fall down in a safe manner in all variants of falls occurring in everyday lives – falls to the back, falls to the front and falls to the side). This would help to establish and evaluate self- protection movements to be applied in all possible situations. Yet another direction for research to be applied should be the diagnosis Barnett, A., Smith, B., Lord, S.R., Williams, M. & Baumand A. (2003). Community- based group exercise improves balance and reduces falls in at-risk older people: A randomized controlled trial. Age Ageing. 32(4), 407-414. Black, A. & Wood, J. (2005). Vision and falls. Clinical and Experimental Optometry, 88, 212-222. Boguszewski, D. & Kerbaum, K. (2011). Judo training as a means of reducing susceptibility to injury during falls. Medycyna Sportowa. Polish Journal of Sports Medicine, 27(3), 205-212. p ( ), Bolach, B., Bolach, E. & Józefowski, P. EUJAPA, Vol. 6, No. 1 14 Susceptibility to injuries of children with VI Boguszewski at al. (2009). Ocena aktywności ruchowej i postawy ciała u młodzieży niedowidzącej. [Assesment of physical activity and body posture visual imairment adolescent]. Postępy Rehabilitacji, 4, 45-51. (2009). Ocena aktywności ruchowej i postawy ciała u młodzieży niedowidzącej. [Assesment of physical activity and body posture visual imairment adolescent]. Postępy Rehabilitacji, 4, 45-51. sport blind people] [in:] Sozański, H., Perkowski, K., Śledziewski, D. (eds.) Kierunki doskonalenia treningu i walki sportowej, AWF Warszawa, 2003, 286-287. Jessup, G.M., Cornel, E. & Bundy, A.C. (2010). The Treasure in Leisure Activities: Fostering Resilience in Young People Who Are Blind. Journal of Visual Impairment & Blindness, 104, 7, 419-430. Bolach, E., Barczyk, K., Bolach, B., Sipko, T. & Skolimowski J. (2007). Evaluation of the influence of ballroom dance upon the posture of blind children. Polish Journal of Physiotherapy, 7(4), 63-70. Kalina, A., Kalina, R.M. & Klukowski, K. (1998). REFERENCES Ćwiczenia unikania zderzeń i bezpiecznego upadku dla potrzeb rehabilitacji, [Exercises of avoid a collisions and safe falls in rehabilitation] Wychowanie Fizyczne i Zdrowotne, 45(1), 20-26. Brambring, M. (2006). Divergent Development of Gross Motor Skills in Children Who Are Blind or Sighted. Journal of Visual Impairment & Blindness, 100, 10, 620-634. Capella-McDonnal, M. (2007). The Need for Health Promotion for Adults Who Are Visually Impaired. Journal of Visual Impairment & Blindness, 101, 3, 133-145. Kalina, R.M., Barczyński, B., Jagiełło, W., Kruszewski, A., Przeździecki, B., Harasymowicz, J., Syska, J. & Szamotulska K. (2008). Teaching of safe falling as most effective element of personal injury prevention in people regardless of gender, age and type of body build – the use of advanced information technologies to monitor the effects of education. Archives of Budo, 4, 82-90. Coleman, A.L., Stone, K., Ewing, S.K., Nevitt, M., Cummings, S. & Cauley, J.A. (2004). Higher risk of multiple falls among elderly women who lose visual acuity. Ophthalmology 111, 857–862. Czerwiński, E., Białoszewski, D., Borowy, P., Kumorek, A. & Białoszewski, A. (2008). Epidemiology, Clinical Significant, Cost and Fall Prevention in Elderly People. Ortopedia Traumatologia Rehabilitacja, 10(5), 419-428. Kalina, R.M., Barczyński, B., Klukowski, K., Langfort, J. & Gąsienica-Walczak, B. (2011). The method to evaluate the susceptibility of injuries during the fall – validation procedure of the specific motor test. Archives of Budo, 7(4), 201-215. Czerwiński, E., Borowy, P. & Jasiak, B. (2006). Current guidelines for using physiotherapy for prevent falls. Ortopedia Traumatologia Rehabilitacja, 8(4), 380- 387. Kalina, R.M., Kruszewski, A., Jagiełło, W. & Włoch, G. (2003). Combat sports propaedeutics – basics of judo. AWF, Warsaw. Czerwiński, E., Kumorek, A., Milert, A. & Borowy P. (2008). Causes of Falls in women in Krakow population. Ortopedia Traumatologia Rehabilitacja, 10(5), 429- 440. Li, F., Harmer, P., Fisher, K.J., McAuley, E., Chaumeton, N., Eckstrom, E. & Wilson, N.L. (2005). Tai Chi and fall reductions in older adults: A randomized controlled trial. J Gerontol A Biol Sci Med Sci. 60(2), 187- 194. Gąsienica-Walczak, B., Barczyński, B.J., Kalina, R.M. & Kucio C. (2010). The effectiveness of two methods of teaching safe falls to physiotherapy students. Archives of Budo, 6(2), 63-71. Manduchi, R. & Kurniawan, S. (2011). Mobility-related accidents experiences by people with visual impairment. Insight: Research & Practice in Visual Impairment & Blindness, 4(2), 44-53. Groen, E.B., Smulders, E., Duysens, J., van Lankveld, W. & Weerdesteyn, V. (2010). REFERENCES Could martial arts fall training be safe for persons with osteoporosis?: a feasibility study. BMC Research Notes, 2010, 3, 111. http://www.biomedcentral.com/1756- 0500/3/111 ( ) Odom, J.V., Odom, C.V. & Leys MJ. (2011). Does improving vision reduce the risk of falls? A Review. Insight: Research & Practice in Visual Impairment & Blindness, 4(2), 92-99. Patel, M., Gomez, S., Lush, D. & Fransson, P.A. (2009). Adaptation and vision change the relationship between muscle activity of Gruszczyński, K. & Rutkowska, I. (2003). Specyfika wychowania fizycznego i sportu osób niewidomych, [Physical education anf EUJAPA, Vol. 6, No. 1 15 Susceptibility to injuries of children with VI Boguszewski at al. non-fallers aged over 65. Age Ageing, 31, 119-125. the lower limbs and body movement during human balance perturbations. Clin Neurophysiol, 120, 601–609 Tinetti, M.E. & Williams, C.S. (1997). Falls, injures due to falls, and the risk of admission to a nursing home. The New England Journal of Medicine, 337(18), 1279-1284. Patino, C.M., McKean-Cowdin, R., Azen, S.P., Allison, J.C., Choudhury, F. & Varma, R. (2010). Central and peripheral visual impairment and the risk of falls and falls with injury. Ophthalmology, 117, 199–206. Rose, D.J. (2008). Preventing falls among older adults: No “one size suits all” intervention strategy. Journal of Rehabilitation Research & Development, 45(8), 1153-1166. Rubenstein, L.Z., Josephson, K.R., Trueblood, P.R., Loy, S., Harker, J.O., Pietruszka, F.M. & Robbins, A.S. (2000). Effects of a group exercise program on strength, mobility, and falls among fall-prone elderly men. J Gerontol A Biol Sci Med Sci. 55(6), M317- 321. Rutkowska, I., Bednarczuk, G. & Skowroński W. (2010). Porównanie równowagi ciała w pozycji stojącej chłopców niewidomych i pełnosprawnych w wieku 6-16 lat. [Comparison of body balance in standing position of blind and sighted 6-16 years old boys] Postępy Rehabilitacji, 2, 29-35. Rutkowska, I., Morgulec-Adamowicz, N. & Skowroński, W. (2009). Porównanie budowy ciała, aktywności i sprawności fizycznej uczniów niewidomych i niedowidzących, [Comparison of body structure, activity and physical fitness of blind and Visual impairment pupils] [in:] Kuder A., Perkowski K., Śledziewski D. (red.) Proces doskonalenia treningu i walki sportowej, PTNKF Warszawa 2009, t. VI, 348-357. Sipko, T., Skolimowski, T., Ostrowska, B. & Anwajler J. (1997). Wpływ chwilowej i trwałe utraty kontroli wzrokowej położenia ciała w przestrzeni na proces regulacji równowagi ciała w pozycji stojącej. [Impact of lack of sight control in body balance regulation process] Fizjoterapia, 5(2), 11-15. Skalska, A., Walczewska, J. & Ocetkiewicz, T. (2003). REFERENCES Wiek, płeć i aktywność fizyczna osób zgłaszających upadki oraz okoliczności ich występowania. Rehabilitacja Medyczna, 7(3), 49-53. Skelton, D.A., Kennedy, J. & Rutherford O.M. (2002). Explosive power and asymmetry in leg muscle function in frequent fallers and EUJAPA, Vol. 6, No. 1 16
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Construction of Environmental Knowledge: Experiences from India
Journal of sustainable development
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1. Background Despite the existence of international guidelines such as Principle 10 of the Rio Declaration passed in the 'Earth Summit' of 1992 (UNCED 1992), it is not still clear how and whether the issues of environment are integrated into the policy process. Positioned amidst ambiguity, are the tensions in how knowledge about the environment is constructed and by whom (Guha 1989). The significance of knowledge of the environment in the policy process is of great concern in the developing world which is rapidly exploiting natural resources to meet the rising demands of its population. A key aspect of this knowledge construction is in conceptualizing who should be involved in making decisions on the environment and how. Particularly in developing countries with a federal structure of government (where multiple levels of government including central, regional and/or local are involved in decision making), construction of the knowledge on the environment and the design of appropriate policy interventions is problematic. For instance, in the India, environment is a subject in the central list (exclusive authority of central government to legislate), land and water are subjects in the state list (exclusive authority of state government to legislate), and forest is a subject in the concurrent list (where both central and state governments have authority to legislate). More recently, the multiplicity of institutions has become particularly posed challenges with the inclusion of multinational enterprises (or corporate actors) in the policy arena. Thus, on one hand, the competing role of multiple institutions has created ambiguity in who should decide and why. While on the other hand, there are arguments to involve individual citizens in environmental governance (DoE 1994; DETR 1999; Barr 2003). Following on this path, Environment Canada (the federal ministry of the environment) coined the phrase ‘environmental citizenship’ as a broad concept to help different actors to think through their rights and duties as inhabitants of planet Earth (Szerzynski 2006). However, such a conceptualization has been vague and brings on board competing sets of arguments. The first is the inherent rights of different stakeholders on matters concerning their environment, such as rights to clean air, a safe environment, or a right to be involved in decision making. The second relates to the values and practices used to nudge citizens to be environmentally aware and responsible in their everyday practices, such as conserving water, switching off lights and so forth (Horton 2006). Abstract This paper explored key issues in how knowledge of the environment is constructed in the Third World. Drawing on which, it showed that there are both explicit and implicit ways in which this knowledge is contested. Particularly, it discussed how implicit forms of contestation are problematic in Third World economies because they are exclusionary and also where such issues become ‘headlines’ only after environmental damage and accompanying social injustices have resulted. It concludes by raising crucial questions for environmental research in the Third World where there is limited role of governments and communities in protecting their environment. words: Environment, Knowledge construction, Roles of actors, Ski Village project, India, Third Worl Construction of Environmental Knowledge: Experiences from India Deepak Gopinath Department of Town and Regional Planning, University of Sheffield Winter Street, Sheffield, S10 2TN, United Kingdom Tel: 44-114-2226913 E-mail: d.gopinath@sheffield.ac.uk Manik D Gopinath Former Research Associate, School of Planning and Architecture, Delhi, India Sheffield, United Kingdom Tel: 44-7733402251 E-mail: manik.gopinath@gmail.com Deepak Gopinath Department of Town and Regional Planning, University of Sheffield Winter Street, Sheffield, S10 2TN, United Kingdom Tel: 44-114-2226913 E-mail: d.gopinath@sheffield.ac.uk Manik D Gopinath Former Research Associate, School of Planning and Architecture, Delhi, India Sheffield, United Kingdom Tel: 44-7733402251 E-mail: manik.gopinath@gmail.com 1 le Development le evelopment Construction of Environmental Knowledge: Experiences from 1.1 Different forms of contestations Due to a lack of clear understanding on how to decide on the environment particularly in developing economies, competing arguments of ‘who should construct knowledge of the environment’ have broadly resulted in two forms of contestations. In some cases, competing arguments of who should construct knowledge of the environment are not explicitly stated. Such forms of ‘implicit’ contestation become particularly problematic in Third World economies where such environmental issues become ‘headlines’ only after the occurrence of environmental damage and accompanying social injustices. With the advent of global players in making decisions of local environments, this has in different ways shaped the roles of governments and communities in the Third World. This has raised concerns about when, how and why actors beyond the local communities should become involved in the decision-making process. Some of these encounters have produced ‘implicit’ contestations within the Indian context (as in the Himalayan Ski Village project). The contestations are ‘implicit’ since such concerns have not reached the attention of the academic and research community, which Smith (2003) rightly notes is partly due to limited awareness of where to look for emerging environmental debates and conflicts. This is also to a certain extent due to the insistence in academic scholarship of ‘reporting after something has happened’ and as a result there is hardly an academic paper that discusses the Ski Village project. On matters relating to the environment and particularly in sensitive eco-systems, opportunities for facilitating basis research to inform policy and applied research appear to be severely limited. In this regard, Hinchliffe and Blowers (2003) argue that environmental disasters are not chance events and that the context should be examined at various levels including an exploration of the socio-political context. Such an approach seems to imply of the need to research the environment starting with the possibility of involving more stakeholders in the decision making process so that there might be limited ecological damage and minimal social impacts. But ‘implicit’ forms of contestation present challenges for environmental research in knowing how such issues can be studied. In this regard, this paper first examines ‘explicit’ contestations, and through an example, brings out a set of questions that can be used as a framework to explore ‘implicit’ forms. More commonly, contestations are explicitly played out through different modes of ‘head-on’ confrontation among different stakeholders supplemented by media publicity (Bingham 2003). 1.1 Different forms of contestations For instance in the Indian context, and particularly with respect to the environment, water management practices in north-western India provide a useful insight into the nature of ‘explicit’ contestations. It was reported in the local media that following the ineffective intervention of multiple institutions in providing water supply to drought-prone areas in north-western India (Mago 2000), communities had explicitly contested the notion ‘that they were living in a water scarce environment’. Particularly, in the states of Gujarat (Das 2000) and Rajasthan (Nanda 2000), the traditional systems of water supply including large tanks, canals and aqueducts were cleaned up so that rainwater in the form of surface run-off could be collected and used for domestic consumption. This then provides one of the possibilities to unpack the tensions in how knowledge of the environment is being constructed – how did the state engage with the local context in constructing knowledge of the environment? Drawing on this inquiry, detailed studies were carried out in the desert city of Jodhpur in western Rajasthan (Gopinath 2001a). During the fieldwork however, it started to emerge that such forms of head-on confrontation and social action started to wither away particularly when quantities of public water supply became more readily available. Such tensions were generally treated as mere ‘cause and effect’- that individuals challenge notions ‘that they are living in a water scare environment’ on the basis of self-interest, i.e. to survive. And when the right to survive is not threatened, then they do not contest. However, such explanations appeared simplistic and did not in any way provide an understanding of the socio-political context. Detailed semi-structured interviews were then carried out with different stakeholders including state actors and community members. Discussions with state actors revealed how knowledge of the environment (that they were living in a water scarce environment) was constructed independent of understanding the local context (Gopinath 2001a). State actors were more concerned in using ‘scientific’ approaches in managing water – including pricing policy, augmenting water supply from neighboring states. More importantly, the state actors did not find the relevance of creating a platform for engaging with communities for whom water management measures were being designed. On the other hand, through the discussions with community members, it was learnt that there are underlying forces (such as the caste system) that were not visible even within ‘explicit’ forms (Gopinath 2001a). 1. Background These theorizations of environmental citizenship seem to suggest a rights-based as well as a responsibility-based approach, and this reflects the two broad traditions underpinning the notion of citizenship: a liberal notion, based on citizen rights, and a republican notion based on citizen responsibilities (Dobson and Bell 2006). However, such approaches are problematic in the Third World, where communities plagued by poverty and unemployment are more concerned on the different means for livelihood, and are to a lesser degree aware of their environmental rights – rights to clean air or the right to be involved in decision making. Also, responsible behavior to the environment is usually nudged through environmental regulations 2 Journal of Sustainable Development March, 2008 March, 2008 that are generally weak and prone to corrupt practices in developing economies. This has in many ways created ambiguity in what the roles of different stakeholders might be in engaging with the environment. that are generally weak and prone to corrupt practices in developing economies. This has in many ways created ambiguity in what the roles of different stakeholders might be in engaging with the environment. 2.1 Under-development in the Third World: tourism as a solution? Amidst the lack of sound institutional arrangements in developing countries, there has been the surge in multinational investments particularly within the tourism industry. This has been supported by claims that tourism investment is a means to reduce poverty and inequality (Cater 1995; Ashley, Boyd, and Goodwin 2000; Erb 2000) – through increased foreign exchange revenues and enhanced employment opportunities for the local population. The range of advantages suggests that the logic of tourism investment is linked to notions of ‘development’. The notion of ‘development’ was initially argued as a path to be traversed by ‘backward societies along the road to civilization’ (Rist 2002). Then with the advent of the ‘new development age’, agendas of ‘development’ as ‘modernization’, was reinforced by leading development models, including Walt Rostow’s ‘unilinear’ model (1960). The Rostovian Take-off model (as it sometimes called) is a linear theory of development which categorizes economies into primary, secondary and tertiary sectors by observing the patterns of change in the history of developed nations (Rostow 1960). This model was based on the premise that ‘development’ is a defining feature of advanced industrial economies and that regions in the Third World can progress toward development only by treading the same path, earlier traversed by advanced industrial economies. This was later followed by the Lewis model which regarded industrialization as the essence of development (Ranis 2004). It however accepted the classical British roadmap to development – of going through a phase of agricultural revolution first (and thus raising agricultural surplus) and then moving into a phase of industrial revolution (Figueroa 2004). Further it also assumed that for overpopulated nations a strategy of industrialization could help transform the subsistence (primary) sector through a process of labor transfer and growth of employment in the industrial sector (Figueroa 2004; Todaro 2000). These linear models of development attempted to reinforce the notion that there were no alternative paths to ‘development’ other than ‘modernization’ and by integrating into the world system. These had influences in the constitution of new international development agencies including the World Bank, and how development was normatively constructed by them. But ‘development’ as ‘modernization’ has been confronted by the ‘dependency school’ – which argues that ‘modernization’ in an unequal international system would not create autonomous entities but rather will force backward regions (the ‘periphery’) into a state of great dependence on advanced industrial nations (the ‘centre’) (Rist 2002). Vol. 1, No. 1 Journal of Sustainable Development it emerged from the rain-fed canals. After which, the water drained to further tanks on the plains where lower castes could access water. But in contemporary Jodhpur and especially in times of severe water shortage, such caste differentiations have been ignored and people come together to challenge notions ‘that they are living in a water scare environment’. But when more quantities of public water supply became available, then traditional water systems are no longer maintained and as a result precious rainwater is lost. At this point, caste differentiations deter communities from making collective action. This then suggested the possibility that underlying factors might be embedded within ‘explicit’ forms of contestation. Thus, this provides a second possibility to unpack the tensions in how knowledge of the environment is being constructed - whether and how the views of communities within their local socio-political context have been taken into consideration while constructing knowledge of the environment? it emerged from the rain-fed canals. After which, the water drained to further tanks on the plains where lower castes could access water. But in contemporary Jodhpur and especially in times of severe water shortage, such caste differentiations have been ignored and people come together to challenge notions ‘that they are living in a water scare environment’. But when more quantities of public water supply became available, then traditional water systems are no longer maintained and as a result precious rainwater is lost. At this point, caste differentiations deter communities from making collective action. This then suggested the possibility that underlying factors might be embedded within ‘explicit’ forms of contestation. Thus, this provides a second possibility to unpack the tensions in how knowledge of the environment is being constructed - whether and how the views of communities within their local socio-political context have been taken into consideration while constructing knowledge of the environment? This section brought out two questions that explored the challenges in constructing knowledge of the local environment. Drawing on these two questions, the following section will build an understanding of the range of ch allenges within ‘implicit’ forms of contestation through the example of the Himalayan Ski Village project in northern India. Such an inquiry has particularly become problematic in Third World where there is the lack of a guiding framework for environmental research. 2. Himalayan Ski Village and ‘implicit’ forms of contestation This section first provides a backdrop to the influence of global forces on developing economies and discusses how tourism investment has been used by multinational enterprises to engage with the environment. The ‘implicit’ form of contestation that has largely been under-researched is then discussed by examining the Himalayan Ski Village project in northern India. Vol. 1, No. 1 More significantly, ‘implicit’ contestations become ‘headlines’ only after the occurrence of environmental damage and accompanying social injustices. 1.1 Different forms of contestations The caste system is a form of social organization drawing on the ‘Brahmanic’ traditions and has existed for many centuries in many parts of India. At the top of the caste hierarchy, are the upper castes consisting of Brahmins (priests), Rajputs (kings) who have historically controlled the land. The middle stratum consists of peasant castes. And, at the bottom, are the landless communities including the group of Untouchables. The respondents revealed how ‘access to water’ was shaped by an individual’s caste identity. Prior to the introduction of public water supply, residents in Jodhpur relied on traditional systems of water supply. However at that time, settlements were designed in such a way that upper caste households were located on higher ground. This design consideration ensured that water was first consumed by the upper-castes as 3 3 Vol. 1, No. 1 2.2 The Himalayan Ski Village Project 2.2 The Himalayan Ski Village Project The northern state of Himachal Pradesh in India is an environmentally sensitive region where more than two-thirds of land area comes under forest land (Winrock International India 2004). Over the last decade, there has been a rampant sanction of projects in Himachal Pradesh ranging from dam constructions to the recent ski-village project. In this regard, Although the extent of the Himalayan environmental degradation received scholarly attention in the early 1980s (Ives and Messerli 1989), recent studies reveal an alarming situation with dwindling fuel wood supplies, and more frequent occurrence of landslides (Sharma, Goel, and Minhas 1991). Of particular concern has been the increased soil erosion: this has lead to increased sediment load in the rivers and has reduced the efficiency and lifespan of the many hydroelectric projects in Himachal Pradesh that provide power not only to the mountain communities but also to the neighboring states (Sharma and Minhas 1993). Of the total potential of hydroelectric power of 97000 MW in India, 21229 MW comes from Himachal Pradesh (Winrock International India 2004). Such large scale projects in sensitive environmental regions have also affected the lives of local communities who are dependent on natural resources for their subsistence. In this regard, many have advocated ‘sustainable livelihoods’ approach in mitigating the effects of such projects on the livelihoods of local communities (Chambers and Conway 1992; Stonich 1998; Scoones 1998). However, amidst such alarming concerns in how large-scale projects have started to affect the livelihoods of local communities, one of the biggest tourism projects in India was sanctioned in Himachal Pradesh in 2006 – the Himalayan Ski Village project. The Himalayan Ski Village project was set up at Kullu valley in the state of Himachal Pradesh by Alfred Ford, the great-grandson of Henry Ford (founder of Ford motors) who is keen on holding international ski tournaments including the Winter Olympic Games. Drawing on his company’s success in running a ski resort at Vedli in Colorado (USA), the Himachal Pradesh state cabinet approved the Preliminary Project Report (PPR) for the setting up of the Rs.3500 Crore (700 million USD) Himalayan Ski Village in November 2005. 2.2 The Himalayan Ski Village Project This tourism project, also called the ‘Fort’ is considered to be one of the biggest FDI (foreign direct investment) in India (The scale of the investment is interesting as according to 2006-07 budget estimates, the HP state annual income is around Rs.8000 Crore or 1.6 billion USD). In addition, the ski village project has been presented as ‘very local-friendly’, by promising to provide over 70 percent employment to the local population. The marketing schedule of the project has been spread over a period of five years starting in 2006. The first phase of the project started early in 2007 with the establishment of the training institute for winter sports. By early 2008, the presale of chalets and condo hotel rooms is expected to commence. The ski village is expected to be fully ready for commercial operations by early 2011 including the development of 700 hotel rooms, restaurants along with an 'Indian Village' shopping experience, twenty thousand square feet of convention facility and an entertainment/performing arts centre. 2.1 Under-development in the Third World: tourism as a solution? While ‘development as modernization’ has been used by multinational enterprises as a guiding principle for tourism investment in the developing economies, dependency theory has been used to explain how Third World countries can assume only a passive role in deciding the nature of tourism projects implemented within their borders (Mowforth and Munt 2003; Britton 1982). But the modernization school of thought has been criticized for adopting technocratic approaches such as cost-benefit analysis; rather than taking into consideration the needs and priorities of local communities (de Kadt 1979). Drawing on these arguments, many have cautioned on the perceived advantages of tourism in addressing persistent poverty and rising inequalities in the developing world (Britton 1982). In addition, based on the experience of past decades, such claims appear to be more of rhetoric than reality. For instance, studies have brought out far-reaching social and environmental impacts caused by tourism projects on local communities (Mathieson and Wall 1987; Wheeller 1997). The debates linking notions of ‘development’ to the environment raises crucial questions as to what the role of governments and communities in the Third World might be in protecting their 4 Journal of Sustainable Development March, 2008 environment and as a result, how they can and should engage with the activities of multinational enterprises (MNE), or enterprises that carry out its commercial operations outside its home or ‘parent’ economy (Bull 1991). To understand the implication of MNE activity and the resultant contestations, the next section takes up the case of the Himalayan Ski Village that is being developed by a multinational enterprise, the Himalayan Ski Village Project Company headed by Alfred Ford. environment and as a result, how they can and should engage with the activities of multinational enterprises (MNE), or enterprises that carry out its commercial operations outside its home or ‘parent’ economy (Bull 1991). To understand the implication of MNE activity and the resultant contestations, the next section takes up the case of the Himalayan Ski Village that is being developed by a multinational enterprise, the Himalayan Ski Village Project Company headed by Alfred Ford. Vol. 1, No. 1 Vol. 1, No. 1 Secondly, of whether the views of communities within their local socio-political context were taken into consideration? Based on the Memorandum of Understanding signed in 2006, the Ski Village project excludes local/indigenous knowledge of the environment from the policy process (Sethi 2006). In this regard, Gardner and Dekens (2007) have shown how local/indigenous knowledge has been used to protect communities from devastating floods in the Kullu valley – by locating the settlements at regular intervals on the hill slopes and surrounding them with areas of cultivated land. But more recently, the value of such local/indigenous knowledge has been ignored, and where rapid deforestation and intensification of human activities have increased the frequency and impact of floods and the damage they cause to the fragile eco-system (Gardner 2002). So on one hand, while the local communities conceive ‘a safe and protected environment’, the advocates of the Ski village project conceptualize the environment as synonymous with ‘rapid deforestation’ and ‘intensification of human activities’. It becomes further problematic when local communities are excluded from the policy process and do not have voice over ‘common property resources’. For instance, Section VII of the MoU gives the Ski Village company “irrevocable license for the use of ski trails and making of snow and ice on such trails for the duration of the [land] lease and for the construction of trail markers, retention ponds, underground water lines and water pumps...”(Sethi 2006). These contradictory understandings of engaging with the environment are seldom made explicit and where local communities remain passive players in the policy process. In addition, previous research seems to suggest the existence of implicit forms of knowledge construction prior to implementation of the Ski Village project – varied infrastructure provisions for different types of villages (highway villages, remote villages etc.), cultural differences between host and tourist populations etc. (Gopinath 2001b). Thus, being positioned in a culture that does not explicitly challenge notions of ‘environment’ conceptualized by powerful stakeholders, presents problems for protecting the fragile eco-system. Moreover, the exploitation of natural resources through large-scale tourism investments raises questions of whether it has compromised the livelihood opportunities of rural communities (Ellis-Jones 1999). Vol. 1, No. 1 Based on fieldwork carried out in 2000, rural populations of the Kullu valley have sustained a traditional way of engaging with members outside their community – through a form of community tourism – and have relied on a defined rural economic base for their survival (Gopinath 2001b). The rural households engaging in tourist activities have traditionally welcomed tourists into their ‘personal space’ in the form of family owned guest houses. Further, tourists are largely considered as members of rural community and not as a community beyond the rural population. By segregating the new, elite tourists from the host rural community, would in some ways create the notion of a ‘gated community’. However in literature, emergence of gated communities is generally viewed as an urban phenomenon where communities (mostly upper-class families) by virtue of their ability to pay, demand a homogenous social culture, a sense of privacy and security from an outside, seemingly alien world (Roitman 2003). And also justification for creation of such communities has been based on prevalence of urban violence and crime (Blakely and Snyder 1997; Caldeira 2000). The debates on ‘gated communities’ becomes interesting in the context of Himalayan Ski Village Project in Kullu valley where the residential development is neither in an urban context nor based on a need for security. But, the notion of development here in Kullu valley, is one of restricted access where public spaces are being privatized (Blakely and Snyder 1997; Goolbar 2002) and new lines are being drawn between an emerging, elite tourists and the host rural community. The sustainability of community tourism now appears threatened especially with the introduction of large scale projects like the Himalayan Ski village project. Thus, there are also concerns that the Ski Village project will bring about greater inequality in the region; particularly through the emergence of an elite-driven, tourism agendum (and for private use) as opposed to a traditional, community-based tourism. 2.3 Unpacking ‘implicit’ contestations This section examines the Ski Village Project through the two questions developed earlier in this paper. Firstly, of how the state had engaged with the local context in constructing knowledge of the environment .The role of the Himachal Pradesh state government appears to be caught between a social objective of providing welfare support to rural areas and to protect the environment, and an economic objective of responding to challenges and constraint of a global market (Mathew 2005). It is true that the role of the state has been quite pronounced in Himachal Pradesh with the National Institute of Rural Development placing the state government’s effort in first position with respect to indicators on human development and infrastructure provision in rural areas across the country (Sanan 2004). However, the upcoming investment opportunities in Himachal Pradesh owing to its tourism potential have in different ways put pressure on the state government to respond adequately. This is clearly reflected in the Memorandum of Understanding (MoU) signed by the state government and the Himalayan Ski Village (HSV) project company in 2006 (Sethi 2006). For instance, the opportunities for investment in property by the elites as well as the commencement of new chartered flights to the region, in contrast to the development of rural roads and infrastructure, seem to suggest that role of the state has become rather insignificant. Also, Section VII of the MoU gives the Ski Village company “water rights in the Project Area, including the tapping of unused nallas /ground water and for building retention ponds for snowmaking and supply to the resort village” (Sethi 2006). In addition, the sheer scale of the investment in the Ski Village project (700 million USD) in relation to the state government’s annual budget (1.6 billion USD) point to the state in the Third World as being a ‘passive player’ in development. Thus, rather than engaging with the local context in constructing knowledge of the environment, the state seems to have accepted the notion of ‘environment’ as conceived by the multinational enterprise promoting the Ski Village project – ‘that tourism investment as a means to reduce poverty and inequality, will result in a sustainable development of the local environment’. 5 5 Journal of Sustainable Development Vol. 1, No. 1 3. Conclusion This paper explored key issues in how knowledge of the environment is developed in the Third World. Cutting across the different aspects of such arguments, the paper showed that there are both explicit and implicit ways in which knowledge is contested. In particular, since implicit forms are under-researched, this paper brought out key challenges by discussing the Ski Village project. Firstly, the paper raises concerns that environmental degradation and accompanying social impacts caused by the Ski Village project are not explicitly revealed. Such concerns point to the influence of competing interest groups within the Kullu valley. Particularly, powerful stakeholders including those who wish to cater for an ‘elite’ tourist population at the Ski Village project seem to be shaping the notion of ‘environment’ in Kullu valley. That the less powerful, local communities are not involved in decisions shaping the environment seems to downplayed in the policy process. This seems to suggest why constructions of the ‘environment’ are implicit and exclusionary. However, such implicit forms of contestations will not prevent environmental degradation and accompanying social impacts. But after such damage has been done, it will provide material for a range of impact studies. Thus, the implementation of a large-scale tourism project such as the Himalayan Ski Village project in rural areas in the developing world raises many concerns particularly in who gets to decide on the nature of such projects. In addition, the paper also raises more general concerns. It brings out challenges in the context of a developing nation where the livelihoods of communities are greatly connected to their immediate environment. Closely linked to this are concerns that existing approaches to environmental planning and management do not adequately make provisions for 6 Journal of Sustainable Development March, 2008 March, 2008 stakeholder involvement in making policy decisions (Oduwaye 2006). This is particularly important because environmental projects that have been implemented without the involvement of intended beneficiaries have had limited success (Sharp 1992). These wider understandings are hoped to inform policy in re-examining the basis for creating knowledge of the environment particularly in the Third World particularly where such issues become ‘headlines’ only after environmental damage and accompanying social injustices have resulted. References Ashley, C., Boyd, C., & Goodwin, H. (2000). Pro-poor tourism: putting poverty at the heart of the tourism agenda. Natural Resource Perspectives 51 (Mar), 1-12. Ashley, C., Boyd, C., & Goodwin, H. (2000). Pro-poor tourism: putting poverty at the heart of the tourism agenda. Natural Resource Perspectives 51 (Mar), 1-12. Barr, S. (2003). Strategies for sustainability: citizens and responsible environmental behavior. Area Barr, S. (2003). Strategies for sustainability: citizens and responsible environmental behavior. Area 35 (3), 227-40. Bingham, N. (2003). Introduction. In N. Bingham, A. Blowers & C. Belshaw (Eds.), Contested Environments. Chichester: John Wiley & Sons Ltd. in association with The Open University. Bingham, N. (2003). Introduction. In N. Bingham, A. Blowers & C. Belshaw (Eds.), Contested Environments. Chichester: John Wiley & Sons Ltd. in association with The Open University. Blakely, E. J., & Snyder, M. G. (1997). Fortress America: Gated Communities in the United States. Cambridge, MA: Brookings Institution Press and Lincoln Institute of Land Policy. Britton, S. G. (1982). The political economy of tourism in the Third World. Annals of Tourism Research 9 (3), 331-358. Bull, A. (1991). The Economics of Travel and Tourism. Melbourne, Australia: Pitman Publishing. Britton, S. G. (1982). The political economy of tourism in the Third World. Annals of Tourism Research 9 (3), 331-358. ll h f l d lb li i bli hi Britton, S. G. (1982). The political economy of tourism in the Third World. Annals of Tourism Resear Bull, A. (1991). The Economics of Travel and Tourism. Melbourne, Australia: Pitman Publishing. Caldeira, T. P. R. (2000). City of Walls. Crime, Segregation and Citizenship in Sao Paulo. California: University of California Press. Cater, E. (1995). Consuming spaces: global tourism. In J. Allen & C. Hamnett (Eds.), A Shrinking World? Global Unevenness and Inequalities. Milton Keynes: Oxford University Press (in association with Open University Press). Chambers, R., & Conway, G. R. 1992. Sustainable rural livelihoods: practical concepts for the 21st century, IDS discussion paper 296. Brighton: Institute of Development Studies (IDS), University of Sussex. Das, R. (2000). Jamnagar cleans up Lakhota lake. Hindustan Times, 28 April 2000, national newspaper published by HT Media Limited, Delhi, India. de Kadt, E. (1979). Social planning for tourism in the developing countries. Annals of Tourism Research 6 (1), 36-48. artment of Environment (DoE). (1994). Sustainable Development: The UK Strategy. London: HMSO Department of Environment Transport and the Regions (DETR). (1999). References Too many water-related ministries leave people high and dry. The Times of India, 24 April 2000, national newspaper published by the Times Group, Delhi, India. Mathew, P. M. (2005). Rural industries and the international market - some issues. Journal of Rural Development 24 (2), 247-70. Mathieson, A., & Wall, G. (1987). Tourism: Economic, Physical, and Social Impacts. Harlow: Longman Scientific & Technical. Mowforth, M., & Munt, I. (2003). Tourism and Sustainability - Development and New Tourism in the Third World. London: Routledge. Nanda, R. (2000). Wellsprings of hope - recharge traditional water systems. Hindustan Times, 11 May 2000, national newspaper published by HT Media Limited, Delhi, India. Oduwaye, L. (2006). Citizen participation in environmental planning and management in Nigeria: suggestions. Journal of Human Ecology 20 (1), 43-48. (2002). The History of Development: From Western Origins to Global Faith. London: Zed Books. Roitman, S. (2003). Who segregates whom? Paper read at Conference on Gated communities: building social division or safer communities? 18-19 September, 2003 at University of Glasgow, Glasgow, United Kingdom. Sanan, D. (2004). Delivering basic public services in Himachal Pradesh - is the success sustainable? Economic and Political Weekly 39 (9), 975-78. Scoones, I. (1998). Sustainable rural livelihoods: a framework for analysis, IDS working paper 72. Brighton: Institute of Development Studies (IDS), University of Sussex. Sethi, A. (2006). On thin ice. Frontline, Volume 23, Issue 7, 8-21 April, 2006, national fortnightly published by the Hindu Group, Chennai, India. Sharma, P. D., Goel, A. K., & Minhas, R. S. (1991). Water and sediment yields into the Sutlej river from the high Himalaya. Mountain Research and Development 11 (2), 87-100. Sharma, P. D., & Minhas, R. S. (1993). Land use and the biophysical environment of Kinnaur district, Himachal Pradesh, India. Mountain Research and Development 13 (1), 41-60. Sharp, R. (1992). Organizing for change: people-power and the role of institutions. In J. Holmberg (Ed.) Policies for a Small Planet. London: Earthscan. Smith, J. (2003). Making environment news. In N. Bingham, A. Blowers & C. Belshaw (Eds.), Contested Environments. Chichester: John Wiley & Sons Ltd. in association with The Open University. Stonich, S. (1998). Political ecology of tourism. Annals of Tourism Research 25 (1), 25-54. Stonich, S. (1998). Political ecology of tourism. Annals of Tourism Research 25 (1), 25-54. Szerzynski, B. (2006). Local landscapes and global belonging: toward a situated citizenship of the environment. In A. Dobson & D. Bell (Eds.), Environmental Citizenship. References A Better Quality of Lif ustainable Development for the UK. London: The Stationary Office. Department of Environment Transport and the Regions (DETR). (1999). A Better Quality of Life: A Strategy for Sustainable Development for the UK. London: The Stationary Office. D b A & B ll D (2006) I d i I A D b & D B ll (Ed ) E i l Ci i hi C b id Dobson, A., & Bell, D. (2006). Introduction. In A. Dobson & D. Bell (Eds.), Environmental Citizenship. Cambridge, MA: The MIT Press. Ellis-Jones, J. (1999). Poverty, land care, and sustainable livelihoods in hillside and mountain regions. Mountain Research and Development 19 (3), 179-190. Erb, M. (2000). Understanding tourist: interpretations from Indonesia. Annals of Tourism Research nderstanding tourist: interpretations from Indonesia. Annals of Tourism Research 27 (3), 709-36. Gardner, J. S. (2002). Natural hazards risk in the Kullu district, Himachal Pradesh, India. The Geographical Review 92 (2), 282-306. Gardner, J. S., & Dekens, J. (2007). Mountain hazards and the resilience of social-ecological systems: lessons learned in India and Canada. Natural Hazards 41 (2), 317-336. Goolbar, A. (2002). Outside the walls: urban gated communities and their regulation within the British Planning System. European Planning Studies 10 (3), 321-334. Gopinath, D. (2001a). Water Management in Arid Areas: Case Study of Jodhpur City. Dissertation submitted for the Master of Planning degree (with specialization in Urban Planning), Department of Urban Planning, School of Planning and Architecture, New Delhi, India. Gopinath, M. D. (2001b). Impact of Tourism on Village Development: Case Study of Kullu Valley, Himachal Pradesh, India. Dissertation submitted toward the Master of Planning degree (with specialization in Regional Planning), Department of Regional Planning, School of Planning and Architecture, New Delhi, India. Guha, R. (1989). The Unquiet Woods: Ecological Change and Peasant Resistance in the Himalayas. Oxford: Oxford University Press. Hinchliffe, S. J., & Blowers, A. T. (2003). Environmental responses: radioactive wastes and uncertainty. In S. J. Hinchliffe & A. T. Blowers (Eds.), Environmental Responses. Chichester: John Wiley & Sons Ltd. in association with The Open University. 7 Vol. 1, No. 1 Journal of Sustainable Development Horton, D. (2006). Demonstrating environmental citizenship? A study of everyday life among green activists. In A. Dobson & D. Bell (Eds.), Environmental Citizenship. Cambridge, MA: The MIT Press. Ives, J. D., & Messerli, B. (1989). The Himalayan Dilemma: Reconciling Development and Conservation. London: Routledge. Mago, C. (2000). References Cambridge, MA: The MIT Press. United Nations Conference on Environment and Development (UNCED). (1992). Agenda 21: Action Plan for the Next Century. Rio de Janerio: United Nations. Wheeller, B. (1997). Tourism's troubled times: responsible tourism not the answer. In L. France (Ed.) The Earthscan Reader in Sustainable Tourism. London: Earthscan. Winrock International India. (2004). Markets for Watershed Protection Services and Improved Livelihood’s in India: A Policy Brief, 2004. Gurgaon, India: Winrock International India. 8 8
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Physiological and Behavioral Response of the Asian Shore Crab, Hemigrapsus sanguineus, 1 to Salinity: Implications for Estuarine Distribution and Invasion 2 3 David M. Hudson1,2*, D. Joseph Sexton2,3,4, Dinsdale Wint2,5, Connor Capizzano6, and Joseph F. 4 Crivello2 5 1 Department of Research and Conservation, The Maritime Aquarium at Norwalk, Norwalk, 6 Connecticut, United States of AmericaThe Maritime Aquarium at Norwalk, 10 N. Water Street, 7 Norwalk, CT 06854 8 2 Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, 9 United States of AmericaUniversity of Connecticut, Dept. of Physiology and Neurobiology, 75 N. 10 Eagleville Rd. U-3156, Storrs, CT 06269-3156 USA 11 3 Department of Biology, Georgia State University, Atlanta, Georgia, United States of AmericaA 12 USA 13 4 Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control, 14 Mycotic Disease Branch, Atlanta, Georgia, United States of America Mycotic Disease Branch, 15 Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control, 16 Atlanta, GA USA 17 5 Momenta Pharmaceuticals, Cambridge, Massachusetts, United States of AmericaA USA 18 6 University of Massachusetts Boston, School for the Environment, 100 William T. Morrissey 19 Blvd., Boston, MA 02125 USASchool for the Environment, University of Massachusetts at 20 Boston, Boston, Massachusetts, United States of America 21 22 *Corresponding Author: dmhudson@gmail.com 23 Physiological and Behavioral Response of the Asian Shore Crab, Hemigrapsus sanguineus, 1 to Salinity: Implications for Estuarine Distribution and Invasion 2 3 David M. Hudson1,2*, D. Joseph Sexton2,3,4, Dinsdale Wint2,5, Connor Capizzano6, and Joseph F. 4 Crivello2 5 1 Department of Research and Conservation, The Maritime Aquarium at Norwalk, Norwalk, 6 Connecticut, United States of AmericaThe Maritime Aquarium at Norwalk, 10 N. Water Street, 7 Norwalk, CT 06854 8 2 Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, 9 United States of AmericaUniversity of Connecticut, Dept. of Physiology and Neurobiology, 75 N. 10 Eagleville Rd. U-3156, Storrs, CT 06269-3156 USA 11 3 Department of Biology, Georgia State University, Atlanta, Georgia, United States of AmericaA 12 USA 13 4 Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control, 14 Mycotic Disease Branch, Atlanta, Georgia, United States of America Mycotic Disease Branch, 15 Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control, 16 Atlanta, GA USA 17 5 Momenta Pharmaceuticals, Cambridge, Massachusetts, United States of AmericaA USA 18 6 University of Massachusetts Boston, School for the Environment, 100 William T. Morrissey 19 Blvd., Boston, MA 02125 USASchool for the Environment, University of Massachusetts at 20 Boston, Boston, Massachusetts, United States of America 21 22 *Corresponding Author: dmhudson@gmail.com 23 Physiological and Behavioral Response of the Asian Shore Crab, Hemigrapsus sanguineus, 1 to Salinity: Implications for Estuarine Distribution and Invasion 2 3 David M. Hudson1,2*, D. Joseph Sexton2,3,4, Dinsdale Wint2,5, Connor Capizzano6, and Joseph F. 4 Crivello2 5 1 Department of Research and Conservation, The Maritime Aquarium at Norwalk, Norwalk, 6 Connecticut, United States of AmericaThe Maritime Aquarium at Norwalk, 10 N. Water Street, 7 Norwalk, CT 06854 8 2 Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, 9 United States of AmericaUniversity of Connecticut, Dept. of Physiology and Neurobiology, 75 N. 10 Eagleville Rd. U-3156, Storrs, CT 06269-3156 USA 11 3 Department of Biology, Georgia State University, Atlanta, Georgia, United States of AmericaA 12 USA 13 Physiological and Behavioral Response of the Asian Shore Crab, Hemigrapsus sanguineus, 1 to Salinity: Implications for Estuarine Distribution and Invasion 2 3 David M. Hudson1,2*, D. Joseph Sexton2,3,4, Dinsdale Wint2,5, Connor Capizzano6, and Joseph F. 4 Crivello2 5 1 Department of Research and Conservation, The Maritime Aquarium at Norwalk, Norwalk, 6 Connecticut, United States of AmericaThe Maritime Aquarium at Norwalk, 10 N. Physiological and Behavioral Response of the Asian Shore Crab, Hemigrapsus sanguineus, 1 Physiological and Behavioral Response of the Asian Shore Crab, Hemigrapsus sanguineus, 1 to Salinity: Implications for Estuarine Distribution and Invasion 2 3 David M. Hudson1,2*, D. Joseph Sexton2,3,4, Dinsdale Wint2,5, Connor Capizzano6, and Joseph F. 4 Crivello2 5 1 Department of Research and Conservation, The Maritime Aquarium at Norwalk, Norwalk, 6 Connecticut, United States of AmericaThe Maritime Aquarium at Norwalk, 10 N. Water Street, 7 Norwalk, CT 06854 8 2 Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, 9 United States of AmericaUniversity of Connecticut, Dept. of Physiology and Neurobiology, 75 N. 10 Eagleville Rd. U-3156, Storrs, CT 06269-3156 USA 11 3 Department of Biology, Georgia State University, Atlanta, Georgia, United States of AmericaA 12 USA 13 4 Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control, 14 Mycotic Disease Branch, Atlanta, Georgia, United States of America Mycotic Disease Branch, 15 Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control, 16 Atlanta, GA USA 17 5 Momenta Pharmaceuticals, Cambridge, Massachusetts, United States of AmericaA USA 18 6 University of Massachusetts Boston, School for the Environment, 100 William T. Morrissey 19 Blvd., Boston, MA 02125 USASchool for the Environment, University of Massachusetts at 20 Boston, Boston, Massachusetts, United States of America 21 22 *Corresponding Author: dmhudson@gmail.com 23 Water Street, 7 Norwalk, CT 06854 8 2 Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, 9 United States of AmericaUniversity of Connecticut, Dept. of Physiology and Neurobiology, 75 N. 10 Eagleville Rd. U-3156, Storrs, CT 06269-3156 USA 11 3 Department of Biology, Georgia State University, Atlanta, Georgia, United States of AmericaA 12 USA 13 4 Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control, 14 Mycotic Disease Branch, Atlanta, Georgia, United States of America Mycotic Disease Branch, 15 Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control, 16 Atlanta, GA USA 17 5 Momenta Pharmaceuticals, Cambridge, Massachusetts, United States of AmericaA USA 18 6 University of Massachusetts Boston, School for the Environment, 100 William T. Morrissey 19 Blvd., Boston, MA 02125 USASchool for the Environment, University of Massachusetts at 20 Boston, Boston, Massachusetts, United States of America 21 22 *Corresponding Author: dmhudson@gmail.com 23 3 Department of Biology, Georgia State University, Atlanta, Georgia, United States of AmericaA 12 USA 13 3 Department of Biology, Georgia State University, Atlanta, Georgia, United States of AmericaA 12 USA 13 4 Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control, 14 Mycotic Disease Branch, Atlanta, Georgia, United States of America Mycotic Disease Branch, 15 Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control, 16 Atlanta, GA USA 17 5 Momenta Pharmaceuticals, Cambridge, Massachusetts, United States of AmericaA USA 18 6 University of Massachusetts Boston, School for the Environment, 100 William T. Morrissey 19 Blvd., Boston, MA 02125 USASchool for the Environment, University of Massachusetts at 20 Boston, Boston, Massachusetts, United States of America 21 22 *Corresponding Author: dmhudson@gmail.com 23 Abstract 9 The invasive Asian shore crab, Hemigrapsus sanguineus, is ubiquitous in the rocky 10 intertidal zone of the western north North Atlantic. A likely contributor to this colonization is that 11 H. sanguineus is able to handle a wide range of salinities, and is thus more likely to spread through 12 a greater geographic area of estuariesadequately defend shelter from competitors within the mid 13 and upper intertidal zone. This studyWe investigatused an effective approached the salinity effects 14 on this animal question by observing survival across a range of salinities, and also running trials 15 to determine the maintenance of hemolymph osmolality under different salinities, and behavioral 16 preference for and avoidance of salinities. We find that H. sanguineus showeds high survival 17 across a broad range of salinities, has had little change in hemolymph osmolality over a short-term 18 salinity shock, and behaviorally distinguishes distinguished between salinities when presented 19 with a choice, regardless ounder both f acclimation salinitiesy of 5 PSU or 35 PSU. Such results 20 suggest H. sanguineus has a hardiness for the rapid changes in salinity that happen in the intertidal 21 zone, yet ishas a capable of willingness to physically movinge to a more optimal salinity. This 22 enhances their competitiveness as an invader, particularly in survivingal of lower salinities that 23 present PSU water strategies in ballast waterchallenges during high-precipitation events in rocky 1 intertidal areas, and partially explains this species’ dominance in this habitat type. 2 3 4 5 6 7 8 9 10 The invasive Asian shore crab, Hemigrapsus sanguineus, is aA particularly successful 11 invasive decapod crustacean species is the invasive Asian shore crab, Hemigrapsus sanguineus, 12 which is now found in estuaries and open coasts in areas along the western Nnorth Atlantic coast 13 (Lohrer et al., 2000; Brousseau et al., 2002) and western Europe, displacing resident species 14 (Lohrer et al., 2000; Brousseau et al., 2002; van den Brink, Wijnhoven & McLay, 2012; 15 Landschoff et al., 2013; Gothland et al., 2013; Gothland et al., 2014). The species has become the 16 most abundant crab in the rocky intertidal in New England (McDermott, 1998; Lohrer & 17 Whitlatch, 2002; Kraemer et al., 2007) since it was first found in New Jersey in 1988 ((McDermott, 18 1998; Williams & McDermott, 1990; Lohrer & Whitlatch, 2002; Kraemer et al., 2007; O’Connor, 19 2014)Williams & McDermott, 1990). Abstract 9 Previous work in this lab and by others investigated the 20 behavioral response of the intertidal and subtidal community to this species’ presence (Hudson et 21 al., 2016) to test the effect of this new member of the community on its neighbors(Epifanio, 2013; 22 Hudson et al., 2016). Conspecific tolerance also enhances its success in overcoming resistance to 23 behavioral response of the intertidal and subtidal community to this species’ presence (Hudson et 21 system by a particular species by incorporating a community component. This is similar to the 4 biologically-based system with five overlapping zones defined for fishes and invertebrates by 5 Bulger et al. (1993), in which zones include: 1) freshwater to 4 PSU; 2) 2 PSU to 14 PSU; 3) 11 16 PSU to 18 PSU; 4) 16 PSU to 27 PSU; and 5) 24 PSU to fully marine. Of these, H. sanguineus 17 would likely reside in zones 4 and 5. This idea has been visited beforeS (Gunter, 1961; Kneib, 18 1984), so this paradigmalinity tolerance may benefitcould therefore be used in the management of 19 PSU to 18 PSU; 4) 16 PSU to 27 PSU; and 5) 24 PSU to fully marine. Of these, H. sanguineus 17 PSU to 18 PSU; 4) 16 PSU to 27 PSU; and 5) 24 PSU to fully marine. Of these, H. sanguineus 17 would likely reside in zones 4 and 5. This idea has been visited beforeS (Gunter, 1961; Kneib, 18 1984), so this paradigmalinity tolerance may benefitcould therefore be used in the management of 19 resources in the context of locational risk for invasion by a particular species. 20 maenas (Towle & Kays, 1986; Cieluch et al., 2004). Crabs osmoregulate utilizing the posterior 12 maenas (Towle & Kays, 1986; Cieluch et al., 2004). Crabs osmoregulate utilizing the posterior 12 ( y ) g g p gill filaments (Koch, 1954; Burnett & Towle, 1990; Lucu & Towle, 2003), with far greater Na+/K+ 13 gill filaments (Koch, 1954; Burnett & Towle, 1990; Lucu & Towle, 2003), with far greater Na+/K+ 13 ATPase transport proteins expressed in the posterior gill than in the anterior gill (Burnett & Towle, 14 1990; Koch, 1954). Abstract 9 This transporter’s role is implicated in osmoregulation in crabs and other 15 crustacean species is well-establishedas well (Reviewed in Callinectes sapidus, Neufeld et al., 16 1980; Uca pugilator, D’Orazio & Holliday, 1985; Uca pugnax, Holliday, 1985; Pacifasticus 17 leniusculus, Henry & Wheatly, 1988; Artemia salina, Holliday et al., 1990; Callinectes sapidus 18 leniusculus, Henry & Wheatly, 1988; Artemia salina, Holliday et al., 1990; Callinectes sapidus 18 and Callinectes similis, Piller et al., 1995; Hemigrapsus nudus, Corotto & Holliday, 1996; 19 Carcinus maenas, Henry et al., 2002 [Reviewed in Lucu & Towle 2003]; Scylla paramamosain, 20 Macrophthalmus banzai, Macrophthalmus abbreviates, Uca lactea, Uca formosensis, Ocypode 21 stimpsoni, Chasmagnathus convexus, Helice formosensis, Eriocheir sinensis, Hemigrapsus 22 sanguineus, Hemigrapsus penicillatus, Perisesarma bidens, Chiromantes dehaani, Tsai & Lin, 23 ) g g y p y p y time of exposure, along with behavior, can therefore be a useful determinant of the implications 2 of salinity change in the whole animal. 3 Salinity stress for H. sanguineus experiences salinity stress belowseems to begin at 15 PSU 4 regardless of acclimation seawater, indicated by increased heart rate and activity level (Depledge, 5 1984). The congener Hemigrapsus crenulatus shows increased oxygen consumption as salinity 6 stress increases (as salinity decreases), strong hyper regulation at low salinities, with increases in 7 regulatory capacity as crab size increases (Urzúa & Urbina, 2017). However, this species is easily 8 exposed to this level of salinities below 15 PSUy during a freshwater event (i.e., rain, snow) in the 9 intertidal zone. Tsai & Lin (2007) noticed little decrease in Na+/K+ ATPase activity in H. 10 sanguineus between 5 PSU and 35 PSU treatments, while optima studies of congeners 11 Hemigrapsus H. crenulatus (Urbina et al., 2010) and Hemigrapsus takanoi (Shinji et al., 2009) 12 determined a 21 PSU optimum and 24.4 PSU optimum, respectively. Similarly, our previous initial 13 gill work found no significant change in Na+/K+ ATPase activity in posterior gill of H. sanguineus 14 when exposed to 35 PSU, 15 PSU, or 5 PSU seawater for 7 days, but did see observe a short-term 15 increase in activity at 2 and 4 hours post-treatment for 15 PSU treatments (Hudson, 2011). 16 Therefore, H. sanguineus has similar osmoregulatory ability with this transporter regardless of 17 treatment, but may be able to increase its activity in the short term. 18 Salinity stress for H. Abstract 9 As cChange in salinity is one of the most common 3 forms of stress in the intertidal zone in estuaries, and several invasive crab species are known to 4 be euryhaline in response (and therefore have the ability to osmoregulate well (Reisser & Forward, 1991; Henry et al., 2006; Roche et al., 2009; Fowler 5 et al., 2011)., Tthis underscores the value here is of a need to investigate how broad salinity tolerancesunderstanding how physiological capacity is related to 6 behavioral choice or avoidance, since both contribute to t are implicated in the invasiveness of a species, i.e., how 7 well a species reproduces and extends its range from its introduction point and starts populations 8 in new places ( (as defined by Rejmánek, 2011). 9 To investigate this interaction between physiology and behavior, the work reported here 10 includes physiological tolerance (i.e., maintenance of hemolymph ion concentration) and survival, 11 but also incorporates the behavioral preference of the animalH. sanguineus as an indicator of true risk of exposurhow well they 12 can avoid riske, mainly utilizing three methods: survival, maintenance of internal ion concentration, and behavioral choice of salinity. With the apparent advantage of H. sanguineus in surviving stressful changes in salinity during ocean crossings, it may arrive with more founding members and be more likely to establish in new areas. Since little change was detectable in gill physiology in previous work, we took a behavioral 13 approach for this work to look atinvestigated sublethal effects by quantifying behavioral avoidance and 14 hemolymph osmolality change, along with investigating differences in overall survivorship over 15 time. This tests the idea that H. sanguineus has an ability to tolerate wide salinity changes for a 16 significant amount of time, and can also behaviorally avoid maladaptive stressful salinities at small spatial 17 scales, as have other species (Teal, 1958; Lagerspetz & Mattila, 1961; Jansson, 1962; Thomas et 18 al., 1981; Ameyaw-Akumfi & Naylor, 1987; McGaw & Naylor, 1992a; McGaw & Naylor, 1992b). 19 This salinity-tolerance character is clearly important in determining invasiveness, particularly in 20 decapods, and sheds light on potential areas they can invade and environments they can alter. 21 Particularly, this research area provides information on the effectiveness of ballast exchange 22 methods, as this is an a major vector for invasive species introduction (Hulme, 2009). 23 Commented [DH1]: Moved to conclusions and edited. Abstract 9 sanguineus experiences salinity stress belowseems to begin at 15 PSU 4 regardless of acclimation seawater, indicated by increased heart rate and activity level (Depledge, 5 1984). The congener Hemigrapsus crenulatus shows increased oxygen consumption as salinity 6 stress increases (as salinity decreases), strong hyper regulation at low salinities, with increases in 7 regulatory capacity as crab size increases (Urzúa & Urbina, 2017). However, this species is easily 8 exposed to this level of salinities below 15 PSUy during a freshwater event (i.e., rain, snow) in the 9 intertidal zone. Tsai & Lin (2007) noticed little decrease in Na+/K+ ATPase activity in H. 10 sanguineus between 5 PSU and 35 PSU treatments, while optima studies of congeners 11 Hemigrapsus H. crenulatus (Urbina et al., 2010) and Hemigrapsus takanoi (Shinji et al., 2009) 12 determined a 21 PSU optimum and 24.4 PSU optimum, respectively. Similarly, our previous initial 13 gill work found no significant change in Na+/K+ ATPase activity in posterior gill of H. sanguineus 14 when exposed to 35 PSU, 15 PSU, or 5 PSU seawater for 7 days, but did see observe a short-term 15 increase in activity at 2 and 4 hours post-treatment for 15 PSU treatments (Hudson, 2011). 16 Therefore, H. sanguineus has similar osmoregulatory ability with this transporter regardless of 17 treatment, but may be able to increase its activity in the short term. 18 Species’ responses to gradients are particularly important in determining where they will 19 fall within a physical range (Case & Taper, 2000), so a wider tolerance will mean a wider 20 geographic footprint is possible. Specifically, salinity tolerance levels can greatly alter distribution 21 of species along a coast (Teal, 1958; Barnes, 1967; Engel, 1977; Felder, 1978; Young, 1978; 22 Young, 1979; Rabalais & Cameron, 1985; Hulathduwa et al., 2007; Fowler et al., 2011; DMH 23 pers. obs.). Freshwater events are common in spring and fall along the eastern coast of the United States, butestuarine areas, and salinity can also change on an 1 hourly timescale with the tides, meaning that organisms living there must rapidly manage these 2 challenges behaviorally and/or physiologically. Abstract 9 approach for this work to look atinvestigated sublethal effects by quantifying behavioral avoidance and 14 hemolymph osmolality change, along with investigating differences in overall survivorship over 15 time. This tests the idea that H. sanguineus has an ability to tolerate wide salinity changes for a 16 1 2 Methods 3 Crabs Adult crabs with carapace widths between 15 mm and 34 mm were collected by 4 hand off Avery Point in Groton, Connecticut, USA under Connecticut Department of 5 Environmental Protection Scientific Collector’s Permits # SC-06040 and # SC-09015. Crabs Crabs 6 were acclimated for at least 14 days in holding tanks at 35 PSU before use. 7 8 Survival 9 A lab-based holding study was performed to evaluate the survival of H. sanguineus 10 immersed into a broad range of salinity treatments typical for euryhaline species. Specifically, 11 cCrabs were exposed to salinity treatments of 1 PSU, 5 PSU, 10 PSU, 15 PSU, and or 35 PSU over 12 for 14 days, given the observed ability of members of the genus Hemigrapsus genus to tolerate 13 low salinities for extended periods of time (McGaw, 2001; Tsai & Lin, 2007). In addition to this 14 typical range of salinities, aThe treatment of 1 PSU treatment, in particular, was included to 15 simulate the use of nearly freshwater surface conditions during precipitation events in estuaries 16 and tide poolsballast in transoceanic shipping as an invasive species control measure. Specimens 17 were kept in tanks at room temperature (~20 °C ) that corresponded with spring and fall 18 environmental conditions from the original capture location, Long Island Sound, including a 12- 19 hour light/dark cycle. Crabs were held in groups, and cannibalism was accounted for as a cause of 20 mortality if it occurred upon observation of mortality events, as were molt failures. Each salinity 21 treatment consisted of 20 males and 20 females, which were fed with shrimp pellets every day to 22 Methods 3 satiety. Crab survival was monitored daily over the course of the 14-day experimental trial where 1 dead specimens were removed upon confirmation. 2 H. sanguineus survivorship over time (i.e., the survival function) was evaluated using 3 methods traditionally used in the context of longitudinal survival analyses. In contrast to “cross- 4 sectional” data, which yield numbers of alive and dead specimens at a specific point in time,L 5 “longitudinal” data provide information on the time animals either died or were last observed alive 6 due to ongoing monitoring of survival (Cox & Oakes, 1984; Benoit et al., 2015). Such longitudinal 7 data for H. sanguineus consist of records for each crab specimen, which include information about 8 the occurrence and timing of an event as well as salinity treatment values and sex that might affect 9 survival (i.e., covariates). Crabs that were still alive when last observed or at the end of the 10 experiment were treated as “right-censored” observations, for which where their time of death wais 11 unknown either because mortality did not occur or was not observed during the holding period the 12 event was not achieved or data collection was too short (Singer & Willett, 2003). 13 A set of non- and semi-parametric longitudinal analyses were first employed to select and 14 evaluate the effect of salinity treatment and sex on a parsimonious set of covariates that best 15 describe the H. sanguineus survival function. The semi-parametric Cox proportional-hazards 16 regression model was initially used given its ability to simultaneously evaluate the additive effect 17 of multiple covariates (Cox, 1972). Preliminary regression model results suggested that the 18 survival function was only dependent upon salinity (Table S1). Consequently, the non-parametric 19 Kaplan-Meier estimator of survival was used to preliminarily identify if each salinity treatment 20 produced distinct survival functions (Kaplan & Meier, 1958; Cox & Oakes, 1984; Fig. S1). The 21 Kaplan-Meier estimator follows the proportion of individuals alive as a function of time in the 22 Commented [DH2]: Comments from CC, other marked-up document. Commented [DH2]: Comments from CC, other marked-up document. Commented [DH3]: Comments from CC, other marked-up document. Commented [DH3]: Comments from CC, other marked-up document. absence of censored observations and is well-suited for univariate analyses with multiple factor 1 levels. 2 absence of censored observations and is well-suited for univariate analyses with multiple factor 1 levels. Methods 3 2 The Peto & Peto modification of the Gehan-Wilcoxon was then used to accept or reject the 3 null hypothesis that there was no statistical difference between survival functions (Harrington & 4 Fleming, 1982). Multiple pairwise comparisons using the Peto & Peto test with Benjamini- 5 Hochberg corrections to adjust for significance value inflation were subsequently applied to 6 determine if and which salinity-dependent survival functions were statistically distinct from one 7 another. Salinity-dependent survival functions that failed to reject the null hypothesis were 8 subsequently combined. Preliminary results indicated survival was only significantly different 9 between the 1 PSU and the 10 PSU, 15 PSU, and 35 PSU treatments (p < 0.01), and also between 10 5 PSU and 35 PSU (p < 0.05) (Table S2). However, due to inconsistent significance values between 11 salinity treatments (Table S2, Figure S1), no objective procedure could be performed to combine 12 the survival functions with confidence given inconsistencies between pairwise comparison 13 significance values (Table S2). For instance, while survival was not statistically different between 14 the 1 PSU and 5 PSU as well as the 5 PSU and 10 PSU groups (p>0.05), they could not be 15 combined since survival between the 1 PSU and 10 PSU groups was statistically significant (p < 16 0.01). Coarser salinity categories were therefore examined and presented for easier interpretation 17 of results, specifically fresh (1 PSU), estuarine (5 – 15 PSU), and seawater (35 PSU) salinity 18 groups. 19 All survival-related analyses were performed using the statistical computing software R 20 (version 3.4.2; R Core Team, 2017) with added functionality from the associated package 21 “survival” (version 2.38; Therneau, 2015) and “survminer” (version 0.4.0; Kassambara & 22 Kosinski, 2017). Statistical significance was accepted at a level of p < 0.05. 23 Commented [DH4]: Comments from CC, other marked-up document. All survival-related analyses were performed using the statistical computing software R 20 (version 3.4.2; R Core Team, 2017) with added functionality from the associated package 21 “survival” (version 2.38; Therneau, 2015) and “survminer” (version 0.4.0; Kassambara & 22 Kosinski, 2017). Statistical significance was accepted at a level of p < 0.05. 23 1 Salinity Preference 2 Individual crabs were presented with Salinity comparisons were varied 7 between pairwise choices between 5, 15, orand 35 PSU for a period of 12 hours, with final location 8 at 12 hoursdata recordedanalyzed, for 25 replicates for each sex and acclimation at two acclimation 9 temperatures (total of ~100 per salinity comparison). Due to the initial high activity of this crab 10 species, final location at 12 hours was considered the “chosen” condition. 11 Behavioral choice of salinity data were analyzed for binary choice by Chi-Square test, and 12 then the probability of leaving starting salinity was analyzed by one-way ANOVA for each of 13 starting salinity, sex, acclimation salinity, and temperature. In order to test interactive effects 14 Interaction between those four factors, multiple two-way was tested by a multi-way ANOVAs 15 were completed with the addition of multiple pairwise comparisons, in the statistical computing 16 software R (version 3.4.2; R Core Team, 2017). 17 18 19 Hemolymph Response to Salinity Change: 20 To quantify hemolymph osmolality response to salinity shock, crabs were acclimated to 21 full-strength seawater salinity (32 PSU) for 14 daystwo weeks to normalize gene expression (Tsai 22 & Lin, 2007), then 40 specimens were exposed for seven days (168 hours) to each of the following 23 a ballast tank, unlike the rapid changes (i.e., ~6 hours) that occur in the littoral zone. Given acclimation 1 conditions have been shown to modify preference behavior in other crustacean species 2 (Hernández, 2006; Gross, 1957), we investigated whether acclimation conditions (temperature and 3 salinity) affected the level of impact this original acclimation period had upon salinity preference. 4 We determinedSubsequent tests were performed to determine whether specimens had any 5 preference for a lower or higher salinity based upon the salinity and temperature during their 6 acclimation period. Individual crabs were presented with Salinity comparisons were varied 7 between pairwise choices between 5, 15, orand 35 PSU for a period of 12 hours, with final location 8 at 12 hoursdata recordedanalyzed, for 25 replicates for each sex and acclimation at two acclimation 9 temperatures (total of ~100 per salinity comparison). Due to the initial high activity of this crab 10 species, final location at 12 hours was considered the “chosen” condition. Salinity Preference 2 Given acclimation 1 conditions have been shown to modify preference behavior in other crustacean species 2 (Hernández, 2006; Gross, 1957), we investigated whether acclimation conditions (temperature and 3 salinity) affected the level of impact this original acclimation period had upon salinity preference. 4 We determinedSubsequent tests were performed to determine whether specimens had any 5 preference for a lower or higher salinity based upon the salinity and temperature during their 6 acclimation period. Individual crabs were presented with Salinity comparisons were varied 7 between pairwise choices between 5, 15, orand 35 PSU for a period of 12 hours, with final location 8 at 12 hoursdata recordedanalyzed, for 25 replicates for each sex and acclimation at two acclimation 9 temperatures (total of ~100 per salinity comparison). Due to the initial high activity of this crab 10 species, final location at 12 hours was considered the “chosen” condition. 11 Behavioral choice of salinity data were analyzed for binary choice by Chi-Square test, and 12 then the probability of leaving starting salinity was analyzed by one-way ANOVA for each of 13 starting salinity, sex, acclimation salinity, and temperature. In order to test interactive effects 14 Interaction between those four factors, multiple two-way was tested by a multi-way ANOVAs 15 were completed with the addition of multiple pairwise comparisons, in the statistical computing 16 software R (version 3.4.2; R Core Team, 2017). 17 18 19 Hemolymph Response to Salinity Change: 20 To quantify hemolymph osmolality response to salinity shock, crabs were acclimated to 21 full-strength seawater salinity (32 PSU) for 14 daystwo weeks to normalize gene expression (Tsai 22 & Lin, 2007), then 40 specimens were exposed for seven days (168 hours) to each of the following 23 a ballast tank, unlike the rapid changes (i.e., ~6 hours) that occur in the littoral zone. Given acclimation 1 conditions have been shown to modify preference behavior in other crustacean species 2 (Hernández, 2006; Gross, 1957), we investigated whether acclimation conditions (temperature and 3 salinity) affected the level of impact this original acclimation period had upon salinity preference. 4 We determinedSubsequent tests were performed to determine whether specimens had any 5 preference for a lower or higher salinity based upon the salinity and temperature during their 6 acclimation period. Salinity Preference 2 The behavioral preference of H. sanguineus to varying for specific salinities was evaluated 3 through a separate lab-based experimental trial with new specimens. This study utilizedSince past 4 literature primarily offered choice between only two salinities, (Teal, 1958; Lagerspetz & Mattila, 5 1961; Jansson, 1962; Thomas et al., 1981; Ameyaw-Akumfi & Naylor, 1987; McGaw & Naylor, 6 1992a, McGaw & Naylor, 1992b), we designed an arena that contained two 10 cm x 10 cm 7 chambers, each with a different salinity and bubbled with an airstone, connected by an above- 8 water bridge to offer a binary choice, consistent with past studies (Teal, 1958; Lagerspetz & 9 Mattila, 1961; Jansson, 1962; Thomas et al., 1981; Ameyaw-Akumfi & Naylor, 1987; McGaw & 10 Naylor, 1992a, McGaw & Naylor, 1992b). H. sanguineus is a highly mobile crab that in initial 11 trials actively ran back and forth between the chambers over the bridge, meaning that it was able 12 to effectively sample the conditions of both chambers. Therefore, individual crabs could chose to 13 either 1) stay in the initial chamber, 2) relocate to the second chamber by using the connecting 14 bridge, or 3) remain on the bridge since these are intertidal crabs. Because this species exists in 15 estuaries in the field and therefore along a broad salinity gradient, individual H. sanguineus were 16 acclimated to either 5 PSU or 35 PSU for a period of at least 14 days prior to the experiment to 17 test the effects of acclimation. Since these are poikilothermic animals, activity increases with 18 temperature. As such, tTemperature effects on preference were quantified by acclimating 19 specimens at either 10 °C or 20 °C at those same salinities to simulate seasonal water temperature 20 differences and gauge the general capacity of the animals to behaviorally regulate during different 21 seasons. An eExtended acclimation times up toof two weeks 14 days wasere used to account for 22 longer exposure to lower salinities further up an estuary and during freshwater influx eventsor in 23 trials actively ran back and forth between the chambers over the bridge, meaning that it was able 12 a ballast tank, unlike the rapid changes (i.e., ~6 hours) that occur in the littoral zone. Salinity Preference 2 11 Behavioral choice of salinity data were analyzed for binary choice by Chi-Square test, and 12 then the probability of leaving starting salinity was analyzed by one-way ANOVA for each of 13 starting salinity, sex, acclimation salinity, and temperature. In order to test interactive effects 14 Interaction between those four factors, multiple two-way was tested by a multi-way ANOVAs 15 were completed with the addition of multiple pairwise comparisons, in the statistical computing 16 software R (version 3.4.2; R Core Team, 2017). 17 18 19 Hemolymph Response to Salinity Change: 20 To quantify hemolymph osmolality response to salinity shock, crabs were acclimated to 21 full-strength seawater salinity (32 PSU) for 14 daystwo weeks to normalize gene expression (Tsai 22 & Lin, 2007), then 40 specimens were exposed for seven days (168 hours) to each of the following 23 salinity treatments: 32 PSU (control), 17.5 PSU, 10 PSU, and 5 PSU. Five animals were taken out 1 of the 32 PSU seawater after the 14-day acclimation period and used as the initial time point A 2 shared “time zero” was used for all treatments from five animals collected after the two-week 3 acclimation. A salinity of 32 PSU was used for the full-strength seawater treatment and salinity of 4 17.5 PSU for the middle salinity treatment, along with low salinity exposures at 10 PSU and 5 5 PSU. Due to high mortality in the survival study for some of the lowest salinities (Figs. 1, S1), the 6 experiment was only run for 7 days. Crab hemolymph was sampled from 5 new animals at each 7 post-exposure time points of 1, 2, 4, 8, 24, 48 and, 72, and 168 hours, and at (7 days (168 hours) 8 and frozen at -80 °C. The early time points were chosen to compare with results for other crabs, 9 as work in another euryhaline crab, Callinectes sapidus, supports little change in observed 10 hemolymph osmolality values within 12 hours (Sommer & Mantel, 1988; Towle, 1997; Henry et 11 al., 2002) of salinity shock. Hemolymph samples were taken with the use of a 21 gauge syringe 12 inserted into the crab’s branchial cavity, and stored at -80 °C in 1.5 mL centrifuge tubes. Samples’ 13 were quantified for hemolymph osmolality was measured after removal from thaw, centrifuged 14 for 1 minute at 10,000 rpm, and run in duplicate on a Wescor 5100C vapor pressure osmometer. Salinity Preference 2 15 Samples were run in duplicate, with the average of the two taken as the value for that sample. 16 These results were then analyzed by two-way ANOVA for effects of exposure time and treatment, 17 along with interactive effects between the two. A repeated measures ANOVA would be 18 inappropriate to analyze hemolymph data, as the individuals were sacrificed at each time point for 19 a separate study of the upregulation of proteins in posterior gill tissue. Each time point was 20 analyzed for differences between the four salinity treatments by a one-way ANOVA with Tukey 21 post-hoc analysis. Time zero was left out of analysis since it was the same for all four treatments. 22 of the 32 PSU seawater after the 14-day acclimation period and used as the initial time point A 2 shared “time zero” was used for all treatments from five animals collected after the two-week 3 acclimation. A salinity of 32 PSU was used for the full-strength seawater treatment and salinity of 4 All statistics were completed in in R statistical computing software (version 3.4.2; R Core Team, 1 2017). 2 3 4 Results 5 6 Survival 7 The semi-parametric Cox proportional hazards regression model indicated that the H. 8 sanguineus survival function was only dependent on salinity treatment with no effect from the sex 9 covariate (Table S1). When survival data were grouped into broader salinity designations for ease 10 of interpretation and applicability to representative scenarios, tThe non-parametric Kaplan-Meier 11 estimator suggested indicated that H. sanguineus survival functions for differed between the fresh, 12 estuarine, and seawater salinity groups were distinct (Fig. 1), which was reaffirmed by the Peto & 13 Peto test against all three survival functions (χ2 = 26.8, d.f. = 2, p <<0.001). No effect of sex was 14 seen on survival as previously mentioned (Table S1). Moreover, multiple pairwise comparisons 15 between all broader salinity survival functions were statistically different, thereby confirming 16 survival was distinct between groupings (Table S3). For instance, tAll multiple pairwise 17 comparisons between broad salinity survival functions failed to reject the null hypothesis and 18 consequently remained separate from one another (Table S3). he difference in survival between 19 the 35 PSU (highest survival) and pooled 5 PSU/10 PSU/15 PSU treatments (high survival but 20 some mortality) was significant (p < 0.05). Commented [CC5]: Dave; not entirely sure this is necessary since it was mentioned as preliminary information in the methods. All statistics were completed in in R statistical computing software (version 3.4.2; R Core Team, 1 All statistics were completed in in R statistical computing software (version 3.4.2; R Core Team, 1 2017). 2 Salinity Preference 2 There were also significant survival differences 21 between the 35 PSU treatment and the 1 PSU treatment (lowest survival rate) (p < 0.001), and 22 between 1 PSU (lowest survival) and the pooled 5 PSU/10 PSU/ 15 PSU treatments (high survival 23 Peto test against all three survival functions (χ2 = 26.8, d.f. = 2, p <<0.001). No effect of sex was 14 between all broader salinity survival functions were statistically different, thereby confirming 16 survival was distinct between groupings (Table S3). For instance, tAll multiple pairwise 7 but some mortality) (p < 0.001) (Table S3). So, it seems that while there is clearly a difference 1 between the highest and lowest salinity treatments, the middle three salinity treatments have a 2 moderate survival rate that is significantly different from both the upper and lower salinity 3 treatments. Interestingly, survival did not differ significantly among the three salinity groups over 4 the first 7 days of observation (p = 0.421). 5 6 Salinity Preference 7 Behavioral preference experiments indicated a significant preference (χ2 = 5.88, d.f. = 1, p 8 < 0.05, n = 75) of H. sanguineus for 35 PSU over 5 PSU seawater at 20 °C regardless of acclimation 9 (Fig. 2D), but no significant preference was exhibited when individuals were given a choice 10 between 35 PSU and 15 PSU (χ2 = 0.653, d.f. = 1, p > 0.05, n = 75), nor for 5 PSU and 15 PSU 11 PSU (χ2 = 1.174, d.f. = 1, p > 0.05, n = 69). This significance appears to come from two sources. 12 Males at 20 °C (Fig. 2B) showed a significant preference for 35 PSU over 5 PSU (χ2 = 9.52, d.f. = 13 1, p < 0.01, n = 42), and also have had a significant difference in preference towards 35 PSU when 14 first acclimated to 35 PSU (χ2 = 7.2, d.f. = 1, p < 0.01, n = 20). Crabs that were acclimated to 5 15 PSU prior to the experiment significantly chose 35 PSU over 5 PSU (χ2 = 4.8, d.f. = 1, p < 0.05, n 16 = 30). Aside from these, there are no other no significant effects of acclimation on final salinity 17 choice in this instance. 18 These data were also analyzed by whether the crab left the starting salinity in any 19 experiments (5 PSU, 15 PSU, or 35 PSU). There was a significant effect of starting salinity on 20 whether crabs where more or less likely to leave (one-way ANOVA, F = 32.55, d.f. = 2, p << 21 0.001, n = 635). Interactions between factors were not significant in the two-way ANOVAs used 22 to determine interactive effects between acclimation salinity and starting salinity nor between 23 These data were also analyzed by whether the crab left the starting salinity in any 19 experiments (5 PSU, 15 PSU, or 35 PSU). There was a significant effect of starting salinity on 20 whether crabs where more or less likely to leave (one-way ANOVA, F = 32.55, d.f. = 2, p << 21 0.001, n = 635). Salinity Preference 7 Interactions between factors were not significant in the two-way ANOVAs used 22 to determine interactive effects between acclimation salinity and starting salinity nor between 23 acclimation salinity and sex (Tables S4 and S5, respectively), but the interaction between starting 1 salinity and temperature was significant (Table S6), and a trend exists for an interaction between 2 sex and temperature (Table S7). Crabs that started in 5 PSU (at both temperatures), whether for 5 3 PSU x 35 PSU or 5 PSU x 15 PSU experiments, were more likely to leave that salinity (move to 4 There was a significant effect of salinity exposure to 32 PSU, 17.5 PSU, 10 PSU and 5 19 PSU seawater (n = 160 total) on hemolymph osmolality for H. sanguineus (Fig. 4) over the course 20 of seven days, by two-way ANOVA, for time of exposure (F = 4.6371, d.f. = 7, p < 0.001), 21 depending on salinity treatment (F = 12.0486, d.f. = 3, p << 0.001), and interaction between time 22 of exposure and treatment (F = 2.9242, d.f. = 21, p < 0.001). Time zero was left out of analysis 23 since it was the same for all four treatments. Salinity treatments were quite variable in hemolymph osmolality under 8 hours of exposure, bu 1 did not significantly vary differ from one another for the 8-hour, 24-hour, and 48-hour treatments, as analyzed by Tukey multiple pairwise comparisons after a one-way ANOVA for each time point. A 2 72 hours, hemolymph osmolality was significantly higher (one-way ANOVA, F = 7.055, d.f. = 3, 3 p < 0.01, n = 20) in the 32 PSU treatment than both the 5 PSU (Tukey’s post-hoc test,  = 0.05, p 4 <0.01) and the 17.5 PSU (Tukey’s post-hoc test,  = 0.05, p < 0.05) treatments. At 168 hours (7 5 days), hemolymph osmolality was significantly different across the four treatments (one-way 6 ANOVA, F = 9.383, d.f. = 3, p < 0.001, n = 20) and the 5 PSU treatment was significantly lower 7 in osmolality than all others (Tukey’s post-hoc test,  = 0.05, vs. 32 PSU p < 0.01, vs. 17.5 PSU p < 0.01, vs. 10 PSU p < 0.01) 8 9 10 Discussion 11 That survival declines for H. sanguineus over time for the 1 PSU treatment (Fig. 1)5 PSU 12 and 1 PSU treatments (Fig. 1, Fig. Commented [CC6]: Dave; attempting to remove confusion by removing the 5 PSU group. At this point, we should be remain consistent with the three groups we used in the main results. This may conflict with some data you have a few sentences later in this paragraph. Salinity Preference 7 S1) is noteworthy, but even prolonged periods of changeover 13 of ballast water to purely freshwater influx may not be effective in keeping out H. sanguineus from 14 surviving to establish a population, since the lowest survival rate after two weeks (ocean crossing 15 time) for these animals is still 65% at 1 PSU. Maintenance of internal hemolymph osmolality over 16 7 days (Fig. 4) by this species is consistent with its ability to survive during the survival trials. The 17 point at which deaths mortality began to occur more oftenincrease in the 1 PSU treatment, (~about 18 day 5), is consistent with the significantly lower internal hemolymph osmolality for the 5 PSU 19 treatment of the hemolymph data only after 7 days of exposure. Work with other euryhaline crabs, 20 like Callinectes sapidus, supports that this ability to maintain hemolymph osmolality values within 21 12 hours (Sommer & Mantel, 1988; Towle, 1997; Henry et al., 2002) helps the animal deal with 22 estuarine osmotic stress. Since the work with This study of H. sanguineus here seesobserved no 23 since it was the same for all four treatments. Salinity treatments were quite variable in hemolymph osmolality under 8 hours of exposure, but 1 Commented [CC6]: Dave; attempting to remove confusion by removing the 5 PSU group. At this point, we should be remain consistent with the three groups we used in the main results. This may conflict with some data you have a few sentences later in this paragraph. If you disagree, feel free to remove. Commented [CC6]: Dave; attempting to remove confusion by removing the 5 PSU group. At this point, we should be remain consistent with the three groups we used in the main results. This may conflict with some data you have a few sentences later in this paragraph. If you disagree, feel free to remove. change in hemolymph osmolality for 48 hours72 hours (three days), this underscoringes the survival ability of this crab and 1 therefore its ability to invade new continentsareas. This finding adds to earlier work whichthat merely indicated 2 that stress is induced at 15 PSU seawater for H. sanguineus (Depledge, 1984). 3 However, survival of in a particular salinity is likely different from avoidance of suboptimal 4 salinities. H. Salinity Preference 7 sanguineusIt individuals maintains a functional amount of Na+/K+ ATPase (Tsai & Lin, 5 2007; Hudson, 2011) to help themit navigate this constantly changing environment, and likely uses 6 behavioral strategies to avoid suboptimal salinities. There could be a major difference with one of 7 these physiological characters and the physiological characters of the previously dominant 8 intertidal crab, Carcinus maenas, which still has a depressed hemolymph osmolality at 7 days in 9 low salinity (Siebers et al., 1982; Henry et al., 2006), that may have impacted its competitive 10 interaction with H. sanguineus and facilitated the latter’s invasiontroduction. As H. sanguineus maintains 11 internal osmolality regardless of salinity treatment over short exposures, it may be more suited 12 than competitors to the varying conditions of the intertidal zone. Therefore, it and may be able to 13 behaviorally maintain its shelter against competitors that leave under suboptimal salinity 14 conditions, much like its congener Hemigrapsus nudus (McGaw, 2001). In the littoral zone, a 15 change in salinity can occur during each tidal cycle and during a period of prolonged precipitation 16 or spring melting, allowing these species to maintain territory if they are not behaviorally affected. 17 In the behavioral salinity choice data, a true choice of salinity was a far lesser signal (Fig. 18 2), and less informative, than the analysis of crabs leaving the starting level of salinity (Fig. 3). 19 The decrease in likelihood of leaving as salinity increased is expected for optimal behavioral 20 moderation of osmotic stress, but even the level of 51.3% of crabs leaving 5 PSU after 12 hours 21 still is far less than the tidal cycle. This means that a large portion of crabs would remain in 22 intertidal areas affected by regular salinity changes. This is an important finding with respect to 23 It is likely that theA large proportion of H. sanguineus individuals stayed in stressful 17 starting salinities of 5 PSU (48.7% of the time did not leave) and 15 PSU (69.1% of the time did 18 common trait to the genus, like their congener H. nudus (McGaw, 2001), and could result in faster 1 Hemigrapsus genus by decreasing species could be successful invaders as well as this probably 3 allows for these crabs to maintain higher quality shelters at low tide while other species move 4 vertically with the changing tides. Salinity Preference 7 sanguineus in the Gulf of Maine (Delaney et al., 2012) with small- 5 scale estuarine behavior will offer a far higher resolution to spatial prediction. As invasions often 6 gain a foothold on a small scale, the overall picture must include how the species in question 7 interacts with these parameters on that the local scale, in order to more accurately predict invasion 8 success. 9 10 Conclusions 11 As survival is high in this crab under low salinity conditions, the effectiveness of ballast 12 water exchange at mid-ocean or with freshwater would likely be ineffective. Additionally, seasonal 13 freshwater input into an estuary , unless it causes particularly low salinity for a long period of time, 14 will probably not greatly affect survival of populations of this species. The findings here indicate 15 an advantage of H. sanguineus in surviving stressful changes in salinity during those periods, so 16 more founding members should survive and therefore be more likely to establish in areas where it 17 is introduced. The level at which H. sanguineus maintains its internal hemolymph osmolality, 18 along with its high survival rate in a broad salinity range in this study, highlight itssome of its 19 particularly adept osmotic regulatoryion characters. However, as the energetic demands of this 20 animal do varybecome more variable as temperature increases (Jungblut, 2017), it is important to 21 investigate the interactive effect of seasonal salinity change on likely distribution. 22 As survival is high in this crab under low salinity conditions, the effectiveness of ballast 12 water exchange at mid-ocean or with freshwater would likely be ineffective. Additionally, seasonal 13 freshwater input into an estuary , unless it causes particularly low salinity for a long period of time, 14 will probably not greatly affect survival of populations of this species. The findings here indicate 15 an advantage of H. sanguineus in surviving stressful changes in salinity during those periods, so 16 more founding members should survive and therefore be more likely to establish in areas where it 17 is introduced. The level at which H. sanguineus maintains its internal hemolymph osmolality, 18 along with its high survival rate in a broad salinity range in this study, highlight itssome of its 19 particularly adept osmotic regulatoryion characters. Salinity Preference 7 When these other species migrate into the intertidal to feed at 5 high tide, there are fewer shelters available, and thus more exposure to predators (Jones & 6 Shulman, 2008) and, at low tide, avian and terrestrial predators. These behavioral differences is 7 may be part of what is responsible for the more subtidal than intertidal distribution of C. maenas 8 we observed in other previous work (Hudson et al., 2016), not seen in the intertidal zone in 9 estuarine areas where it does not overlap with H. sanguineus (Behrens Yamada & Gillespie, 2008; 10 Amaral et al., 2009). , D. Additionally, ecreased desiccation of the smaller size of H. sanguineus 11 may make it able to usinge of microhabitats in intertidal cobble fields that cause it to experience 12 lesser desiccationwhen compared to than the larger C. maenas (Altieri et al., 2010) may also have 13 contributed to this intertidal dominance. This is also, as is true for the mud crab Eurypanopeus 14 depressus in intertidal oyster reefs (Grant & McDonald, 1979). This is particularly evident in the 15 large quantity of C. maenas found in the intertidal zone in areas where it does not overlap with H. 6 sanguineus (Behrens Yamada & Gillespie, 2008; Amaral et al., 2009), whereas H. sanguineus does 7 large quantity of C. maenas found in the intertidal zone in areas where it does not overlap with H. 16 sanguineus (Behrens Yamada & Gillespie, 2008; Amaral et al., 2009), whereas H. sanguineus does 17 not seem to have high densities in the subtidal (Hudson et al., 2016). 18 large quantity of C. maenas found in the intertidal zone in areas where it does not overlap with H. 16 g q y p sanguineus (Behrens Yamada & Gillespie, 2008; Amaral et al., 2009), whereas H. sanguineus does 17 not seem to have high densities in the subtidal (Hudson et al 2016) 18 characters synthesized with ecological and biogeographical theory will help facilitate our 1 understanding of these processes. Behavior is becoming more prevalent as an explanation for 2 invasionves’ success (Weis, 2010), and this study adds to our understanding of how this invader’s 3 distribution and use pattern arises from its physiology and behavior. Combiningation of large-scale 4 physical models as done for H. Salinity Preference 7 However, as the energetic demands of this 20 animal do varybecome more variable as temperature increases (Jungblut, 2017), it is important to 21 investigate the interactive effect of seasonal salinity change on likely distribution. 22 The genus Hemigrapsus includes two prominent invaders in Europe and North America, 1 as H. takanoi demonstrates a wide salinity tolerance (Shinji et al., 2009) and invaded Europe 2 (originally misidentified as H. penicillatus) (Gollasch, 1999; Asakura & Watanabe, 2005) shortly 3 followed by H. sanguineus (d’Udekem d’Acoz & Fasse, 2002). The combination of the effects of 4 the behavioral dominance of H. sanguineus for shelter (Hudson et al., 2016) with its ability to 5 withstand salinity changes give it a unique ability to maintain valuable intertidal shelter from 6 predators and competitors during changes in tides and freshwater events. In the end, H. sanguineus 7 is a hardy, effective invasive species This in combination with broad salinity tolerances and 8 preferences , which provide it the opportunity for it to outlast competitors for shelter and food 9 when exposed to maladaptive suboptimal salinities, and allows it to survive ballast water changes. 10 11 12 Acknowledgements 13 The authors thank Stephen McCormick, Mike O’Dea, Amy Bataille and Dr. Larry Renfro 14 for advice and equipment, Igor Gurevich and the Aneskievich lab for use of imaging equipment, 15 and to Adriana Hudson, Kurt Schwenk, Courtney McGinnis, and Mike Gilman, and Barrett 16 Christie. Additional thanks to Hugues Benoît for his input and programming assistance with 17 survival modeling. 18 19 20 References 21 22 23 Altieri AH, van Wesenbeeck BK, Bertness MD, Silliman BR. 2010. Facilitation cascade drives 1 positive relationship between native biodiversity and invasion success. Ecology 91:1269–1275. 2 DOI: 10.1890/09-1301.1. 3 Altieri AH, van Wesenbeeck BK, Bertness MD, Silliman BR. 2010. Facilitation cascade drives 1 positive relationship between native biodiversity and invasion success. Ecology 91:1269–1275. 2 DOI: 10.1890/09-1301.1. 3 Altieri AH, van Wesenbeeck BK, Bertness MD, Silliman BR. 2010. Facilitation cascade drives 1 positive relationship between native biodiversity and invasion success. Ecology 91:1269–1275. 2 DOI: 10.1890/09-1301.1. 3 4 Amaral V, Cabral HN, Jenkins S, Hawkins S, Paula J. 2009. Comparing quality of estuarine and 5 nearshore intertidal habitats for Carcinus maenas. Estuarine, Coastal and Shelf Science 83:219– 6 226. DOI: 10.1016/j.ecss.2009.03.029. 7 8 Ameyaw-Akumfi C, Naylor E. 1987. Spontaneous and induced components of salinity preference 9 behaviour in Carcinus maenas. Salinity Preference 7 Marine Ecology Progress Series 37:153–158. 10 11 Asakura A, Watanabe S. 2005. Hemigrapsus takanoi, new species, a sibling species of the common 12 Japanese intertidal crab H. penicillatus (Decapoda: Brachyura: Grapsoidea). Journal of 13 Crustacean Biology 25:279–292. DOI: 10.1651/C-2514. 14 15 Barnes R. 1967. The osmotic behaviour of a number of grapsoid crabs with respect to their 16 differential penetration of an estuarine system. The Journal of Experimental Biology 47:535–551. 17 18 Behrens Yamada S, Gillespie G. 2008. Will the European green crab (Carcinus maenas) persist in 19 the Pacific Northwest? ICES Journal of Marine Science 65:725–729. DOI: 20 10.1093/icesjms/fsm191. 21 22 DOI: 10.1890/09-1301.1. 3 4 Amaral V, Cabral HN, Jenkins S, Hawkins S, Paula J. 2009. Comparing quality of estuarine and 5 nearshore intertidal habitats for Carcinus maenas. Estuarine, Coastal and Shelf Science 83:219– 6 226. DOI: 10.1016/j.ecss.2009.03.029. 7 8 Ameyaw-Akumfi C, Naylor E. 1987. Spontaneous and induced components of salinity preference 9 behaviour in Carcinus maenas. Marine Ecology Progress Series 37:153–158. 10 11 Asakura A, Watanabe S. 2005. Hemigrapsus takanoi, new species, a sibling species of the common 12 Japanese intertidal crab H. penicillatus (Decapoda: Brachyura: Grapsoidea). Journal of 13 Crustacean Biology 25:279–292. DOI: 10.1651/C-2514. 14 15 Barnes R. 1967. The osmotic behaviour of a number of grapsoid crabs with respect to their 16 Amaral V, Cabral HN, Jenkins S, Hawkins S, Paula J. 2009. Comparing quality of estuarine and 5 nearshore intertidal habitats for Carcinus maenas. Estuarine, Coastal and Shelf Science 83:219– 6 226. DOI: 10.1016/j.ecss.2009.03.029. 7 Ameyaw-Akumfi C, Naylor E. 1987. Spontaneous and induced components of salinity preference 9 behaviour in Carcinus maenas. Marine Ecology Progress Series 37:153–158. 10 Asakura A, Watanabe S. 2005. Hemigrapsus takanoi, new species, a sibling species of the common 12 Japanese intertidal crab H. penicillatus (Decapoda: Brachyura: Grapsoidea). Journal of 13 Crustacean Biology 25:279–292. DOI: 10.1651/C-2514. 14 Asakura A, Watanabe S. 2005. Hemigrapsus takanoi, new species, a sibling species of the common 12 Japanese intertidal crab H. penicillatus (Decapoda: Brachyura: Grapsoidea). Journal of 13 Crustacean Biology 25:279–292. DOI: 10.1651/C-2514. 14 Barnes R. 1967. The osmotic behaviour of a number of grapsoid crabs with respect to their 16 differential penetration of an estuarine system. The Journal of Experimental Biology 47:535–551. 17 18 Behrens Yamada S, Gillespie G. 2008. Will the European green crab (Carcinus maenas) persist in 19 the Pacific Northwest? ICES Journal of Marine Science 65:725–729. DOI: 20 10.1093/icesjms/fsm191. Salinity Preference 7 21 Benoît HP, Capizzano CW, Knotek RJ, Rudders DB, Sulikowski JA, Dean MJ, Hoffman W, 1 Zemeckis DR, Mandelman JW. 2015. A generalized model for longitudinal short- and long-term 2 mortality data for commercial fishery discards and recreational fishery catch-and-releases. ICES 3 Journal of Marine Science: Journal du Conseil 72:1834–1847. DOI: 10.1093/icesjms/fsv039. 4 5 van den Brink AM, Wijnhoven S, McLay CL. 2012. Competition and niche segregation following 6 the arrival of Hemigrapsus takanoi in the formerly Carcinus maenas dominated Dutch delta. 7 Journal of Sea Research 73:126–136. DOI: 10.1016/j.seares.2012.07.006. 8 9 Brousseau DJ, Baglivo JA, Filipowicz A, Sego L, Alt C. 2002. An experimental field study of site 10 fidelity and mobility in the Asian shore crab, Hemigrapsus sanguineus. Northeastern Naturalist 11 9:381–390. DOI: 10.1656/1092-6194(2002)009[0381:AEFSOS]2.0.CO;2. 12 13 Bulger AJ, Hayden BP, Monaco ME, Nelson DM, McCormick-Ray MG. 1993. Biologically-based 14 estuarine salinity zones derived from a multivariate analysis. Estuaries 16:311. DOI: 15 10.2307/1352504. 16 17 Burnett LE, Towle DW. 1990. Sodium ion uptake by perfused gills of the blue crab Callinectes 18 sapidus: effects of ouabain and amiloride. Journal of Experimental Biology 149:293. 19 20 Case TJ, Taper ML. 2000. Interspecific competition, environmental gradients, gene flow, and the 21 coevolution of species’ borders. The American Naturalist 155:583–605. DOI: 10.1086/303351. 22 23 Benoît HP, Capizzano CW, Knotek RJ, Rudders DB, Sulikowski JA, Dean MJ, Hoffman W, 1 Zemeckis DR, Mandelman JW. 2015. A generalized model for longitudinal short- and long-term 2 mortality data for commercial fishery discards and recreational fishery catch-and-releases. ICES 3 Journal of Marine Science: Journal du Conseil 72:1834–1847. DOI: 10.1093/icesjms/fsv039. 4 5 van den Brink AM, Wijnhoven S, McLay CL. 2012. Competition and niche segregation following 6 the arrival of Hemigrapsus takanoi in the formerly Carcinus maenas dominated Dutch delta. 7 Journal of Sea Research 73:126–136. DOI: 10.1016/j.seares.2012.07.006. 8 van den Brink AM, Wijnhoven S, McLay CL. 2012. Competition and niche segregation following 6 the arrival of Hemigrapsus takanoi in the formerly Carcinus maenas dominated Dutch delta. 7 Journal of Sea Research 73:126–136. DOI: 10.1016/j.seares.2012.07.006. 8 Brousseau DJ, Baglivo JA, Filipowicz A, Sego L, Alt C. 2002. An experimental field study of site 10 fidelity and mobility in the Asian shore crab, Hemigrapsus sanguineus. Northeastern Naturalist 11 9:381–390. DOI: 10.1656/1092-6194(2002)009[0381:AEFSOS]2.0.CO;2. 12 Brousseau DJ, Baglivo JA, Filipowicz A, Sego L, Alt C. 2002. Salinity Preference 7 An experimental field study of site 10 fidelity and mobility in the Asian shore crab, Hemigrapsus sanguineus. Northeastern Naturalist 11 9:381–390. DOI: 10.1656/1092-6194(2002)009[0381:AEFSOS]2.0.CO;2. 12 Cieluch U. 2004. Ontogeny of osmoregulatory structures and functions in the green crab Carcinus 1 maenas (Crustacea, Decapoda). Journal of Experimental Biology 207:325–336. DOI: 2 10.1242/jeb.00759. 3 4 Colnar AM, Landis WG. 2007. Conceptual Model Development for Invasive Species and a 5 Regional Risk Assessment Case Study: The European Green Crab, Carcinus maenas, at Cherry 6 Point, Washington, USA. Human and Ecological Risk Assessment: An International Journal 7 13:120–155. DOI: 10.1080/10807030601105076. 8 9 Corotto FS, Holliday CW. 1996. Branchial Na, K-ATPase and osmoregulation in the purple shore 10 crab, Hemigrapsus nudus (Dana). Comparative Biochemistry and Physiology Part A: Physiology 11 113:361–368. DOI: 10.1016/0300-9629(95)02076-4. 12 13 Cox DR. 1972. Regression models and life-tables. Journal of the Royal Statistical Society. Series 14 B (Methodological) 34:187–220. 15 16 Cox DR, Oakes D. 1984. Analysis of survival data. London ; New York: Chapman and Hall. 17 Delaney DG., Edwards PK., Leung B. 2012. Predicting regional spread of non-native species using 18 oceanographic models: validation and identification of gaps. Marine Biology 159:269–282. DOI: 19 10.1007/s00227-011-1805-5. 20 21 Depledge MH. 1984. Cardiac activity in the intertidal crab Hemigrapsus sanguineus (De Haan). 22 Asian Marine Biology 1:115–123. 23 Corotto FS, Holliday CW. 1996. Branchial Na, K-ATPase and osmoregulation in the purple shore 10 crab, Hemigrapsus nudus (Dana). Comparative Biochemistry and Physiology Part A: Physiology 11 113:361–368. DOI: 10.1016/0300-9629(95)02076-4. 12 13 Cox DR. 1972. Regression models and life-tables. Journal of the Royal Statistical Society. Series 14 B (Methodological) 34:187–220. 15 Cox DR, Oakes D. 1984. Analysis of survival data. London ; New York: Chapman and Hall. 17 1 D’Orazio SE, Holliday CW. 1985. Gill Na,K-ATPase and osmoregulation in the sand fiddler crab, 2 Uca pugilator. Physiological Zoology 58:364–373. DOI: 10.1086/physzool.58.4.30156011. 3 4 Engel DW. 1977. Comparison of the osmoregulatory capabilities of two portunid crabs, 5 Callinectes sapidus and C. similis. Marine Biology 41:275–279. DOI: 10.1007/BF00394915. 6 7 Epifanio CE. 2013. Invasion biology of the Asian shore crab Hemigrapsus sanguineus: A review. 8 Journal of Experimental Marine Biology and Ecology 441:33–49. DOI: 9 10.1016/j.jembe.2013.01.010. 10 11 Felder DL. 1978. Osmotic and ionic regulation in several Western Atlantic Callianassidae 12 (Crustacea, Decapoda, Thalassinidea). The Biological Bulletin 154:409–429. DOI: 13 10.2307/1541068. 14 15 Fowler AE, Gerner NV, Sewell MA. 2011. D’Orazio SE, Holliday CW. 1985. Gill Na,K-ATPase and osmoregulation in the sand fiddler crab, 2 Salinity Preference 7 Temperature and salinity tolerances of Stage 1 zoeae 16 predict possible range expansion of an introduced portunid crab, Charybdis japonica, in New 17 Zealand. Biological Invasions 13:691–699. DOI: 10.1007/s10530-010-9860-2. 18 19 Fowler A, Forsström T, von Numers M, Vesakoski O. 2013. The North American mud crab 20 Rhithropanopeus harrisii (Gould, 1841) in newly colonized Northern Baltic Sea: distribution and 21 ecology. Aquatic Invasions 8:89–96. DOI: 10.3391/ai.2013.8.1.10. 22 23 Uca pugilator. Physiological Zoology 58:364–373. DOI: 10.1086/physzool.58.4.30156011. 3 4 Engel DW. 1977. Comparison of the osmoregulatory capabilities of two portunid crabs, 5 Callinectes sapidus and C. similis. Marine Biology 41:275–279. DOI: 10.1007/BF00394915. 6 Formatted: Font: Italic Gollasch S. 1998. The Asian decapod Hemigrapsus penicillatus (de Haan, 1835) (Grapsidae, 1 Decapoda) introduced in European waters: status quo and future perspective. Helgoländer 2 Meeresuntersuchungen 52:359–366. DOI: 10.1007/BF02908909. 3 Gollasch S. 1998. The Asian decapod Hemigrapsus penicillatus (de Haan, 1835) (Grapsidae, 1 Decapoda) introduced in European waters: status quo and future perspective. Helgoländer 2 Meeresuntersuchungen 52:359–366. DOI: 10.1007/BF02908909. 3 4 Gothland M, Dauvin JC, Denis L, Dufossé F, Jobert S, Ovaert J, Pezy JP, Tous Rius A, Spilmont 5 N. 2014. Biological traits explain the distribution and colonisation ability of the invasive shore 6 crab Hemigrapsus takanoi. Estuarine, Coastal and Shelf Science 142:41–49. DOI: 7 10.1016/j.ecss.2014.03.012. 8 9 Gothland M, Dauvin J-C, Denis L, Jobert S, Ovaert J, Pezy J-P, Spilmont N. 2013. Additional 10 records and distribution (2011-2012) of Hemigrapsus sanguineus (De Haan, 1835) along the 11 French coast of the English Channel. Management of Biological Invasions 4:305–315. DOI: 12 10.3391/mbi.2013.4.4.05. 13 14 Grant J, McDonald J. 1979. Desiccation tolerance of Eurypanopeus depressus (Smith) (Decapoda: 15 Xanthidae) and the exploitation of microhabitat. Estuaries 2:172. DOI: 10.2307/1351731. 16 17 Gross WJ. 1957. A behavioral mechanism for osmotic regulation in a semi-terrestrial crab. The 18 Biological Bulletin 113:268–274. DOI: 10.2307/1539084. 19 20 Gunter G. 1961. Some relations of estuarine organisms to salinity. Limnology and Oceanography 21 6:182–190. DOI: 10.4319/lo.1961.6.2.0182. 22 23 Gothland M, Dauvin JC, Denis L, Dufossé F, Jobert S, Ovaert J, Pezy JP, Tous Rius A, Spilmont 5 N. 2014. Biological traits explain the distribution and colonisation ability of the invasive shore 6 crab Hemigrapsus takanoi. Estuarine, Coastal and Shelf Science 142:41–49. DOI: 7 10.1016/j.ecss.2014.03.012. 8 Gothland M, Dauvin JC, Denis L, Dufossé F, Jobert S, Ovaert J, Pezy JP, Tous Rius A, Spilmont 5 N. 2014. Salinity Preference 7 Biological traits explain the distribution and colonisation ability of the invasive shore 6 crab Hemigrapsus takanoi. Estuarine, Coastal and Shelf Science 142:41–49. DOI: 7 10.1016/j.ecss.2014.03.012. 8 9 Gothland M, Dauvin J-C, Denis L, Jobert S, Ovaert J, Pezy J-P, Spilmont N. 2013. Additional 10 records and distribution (2011-2012) of Hemigrapsus sanguineus (De Haan, 1835) along the 11 French coast of the English Channel. Management of Biological Invasions 4:305–315. DOI: 12 10.3391/mbi.2013.4.4.05. 13 14 Grant J, McDonald J. 1979. Desiccation tolerance of Eurypanopeus depressus (Smith) (Decapoda: 15 Xanthidae) and the exploitation of microhabitat. Estuaries 2:172. DOI: 10.2307/1351731. 16 Grant J, McDonald J. 1979. Desiccation tolerance of Eurypanopeus depressus (Smith) (Decapoda: 15 Xanthidae) and the exploitation of microhabitat. Estuaries 2:172. DOI: 10.2307/1351731. 16 Gross WJ. 1957. A behavioral mechanism for osmotic regulation in a semi-terrestrial crab. The 18 Biological Bulletin 113:268–274. DOI: 10.2307/1539084. 19 Gross WJ. 1957. A behavioral mechanism for osmotic regulation in a semi-terrestrial crab. The 18 Biological Bulletin 113:268–274. DOI: 10.2307/1539084. 19 Gunter G. 1961. Some relations of estuarine organisms to salinity. Limnology and Oceanography 21 6:182–190. DOI: 10.4319/lo.1961.6.2.0182. 22 Harrington DP, Fleming TR. 1982. A class of rank test procedures for censored survival data. 1 Biometrika 69:553–566. DOI: 10.1093/biomet/69.3.553. 2 3 Henry RP, Garrelts EE, McCarty MM, Towle DW. 2002. Differential induction of branchial 4 carbonic anhydrase and NA+/K+ ATPase activity in the euryhaline crab, Carcinus maenas, in 5 response to low salinity exposure. Journal of Experimental Zoology 292:595–603. DOI: 6 10.1002/jez.10075. 7 8 Henry RP, Thomason KL, Towle DW. 2006. Quantitative changes in branchial carbonic anhydrase 9 activity and expression in the euryhaline green crab, Carcinus maenas, in response to low salinity 10 exposure. Journal of Experimental Zoology Part A: Comparative Experimental Biology 11 305A:842–850. DOI: 10.1002/jez.a.298. 12 13 Henry RP, Wheatly MG. 1988. Dynamics of salinity adaptations in the euryhaline crayfish 14 Pacifasticus leniusculus. Physiological Zoology 61:260–271. DOI: 15 10.1086/physzool.61.3.30161239. 16 17 Herborg L-M, Rudnick DA, Siliang Y, Lodge DM, MacIsaac HJ. 2007. Predicting the range of 18 Chinese mitten crabs in Europe. Conservation Biology 21:1316–1323. DOI: 10.1111/j.1523- 19 1739.2007.00778.x. 20 21 Harrington DP, Fleming TR. 1982. A class of rank test procedures for censored survival data. 1 Biometrika 69:553–566. DOI: 10.1093/biomet/69.3.553. 2 Henry RP, Garrelts EE, McCarty MM, Towle DW. 2002. Differential induction of branchial 4 carbonic anhydrase and NA+/K+ ATPase activity in the euryhaline crab, Carcinus maenas, in 5 response to low salinity exposure. Salinity Preference 7 Journal of Experimental Zoology 292:595–603. DOI: 6 10.1002/jez.10075. 7 Henry RP, Garrelts EE, McCarty MM, Towle DW. 2002. Differential induction of branchial 4 carbonic anhydrase and NA+/K+ ATPase activity in the euryhaline crab, Carcinus maenas, in 5 response to low salinity exposure. Journal of Experimental Zoology 292:595–603. DOI: 6 10.1002/jez.10075. 7 8 Henry RP, Thomason KL, Towle DW. 2006. Quantitative changes in branchial carbonic anhydrase 9 activity and expression in the euryhaline green crab, Carcinus maenas, in response to low salinity 10 exposure. Journal of Experimental Zoology Part A: Comparative Experimental Biology 11 305A:842–850. DOI: 10.1002/jez.a.298. 12 13 Henry RP, Wheatly MG. 1988. Dynamics of salinity adaptations in the euryhaline crayfish 14 Pacifasticus leniusculus. Physiological Zoology 61:260–271. DOI: 15 10.1086/physzool.61.3.30161239. 16 17 Herborg L-M, Rudnick DA, Siliang Y, Lodge DM, MacIsaac HJ. 2007. Predicting the range of 18 Chinese mitten crabs in Europe. Conservation Biology 21:1316–1323. DOI: 10.1111/j.1523- 19 1739.2007.00778.x. 20 21 8 Henry RP, Thomason KL, Towle DW. 2006. Quantitative changes in branchial carbonic anhydrase 9 activity and expression in the euryhaline green crab, Carcinus maenas, in response to low salinity 10 exposure. Journal of Experimental Zoology Part A: Comparative Experimental Biology 11 305A:842–850. DOI: 10.1002/jez.a.298. 12 Hernández RM, Bückle R. LF, Palacios E, Barón S. B. 2006. Preferential behavior of white shrimp 1 Litopenaeus vannamei (Boone 1931) by progressive temperature–salinity simultaneous 2 interaction. Journal of Thermal Biology 31:565–572. DOI: 10.1016/j.jtherbio.2006.05.008. 3 4 Hobbs N-VS, Cobb JS, Thornber CS. 2017. Conspecific tolerance and heterospecific competition 5 as mechanisms for overcoming resistance to invasion by an intertidal crab. Biological Invasions 6 19:765–772. DOI: 10.1007/s10530-016-1290-3. 7 8 Holliday CW. 1985. Salinity-induced changes in gill Na, K-ATPase activity in the mud fiddler 9 crab, Uca pugnax. Journal of Experimental Zoology 233:199–208. DOI: 10.1002/jez.1402330206. 10 11 Holliday CW, Roye DB, Roer RD. 1990. Salinity-induced changes in branchial Na+/K+- ATPase 12 activity and transepithelial potential difference in the brine shrimp Artemia sauna. Journal of 13 Experimental Biology 151:279. 14 15 Hudson DM. 2011. Characteristics contributing to invasiveness of the Asian Shore Crab, 16 Hemigrapsus sanguineus. D. Phil. Thesis. Storrs: University of Connecticut. 17 18 Hudson DM, Reagan D, Crivello JF. 2016. Community shelter use in response to two benthic 19 decapod predators in the Long Island Sound. PeerJ 4:e2265. DOI: 10.7717/peerj.2265. 20 21 Holliday CW. 1985. Salinity-induced changes in gill Na, K-ATPase activity in the mud fiddler 9 crab, Uca pugnax. Salinity Preference 7 Journal of Experimental Zoology 233:199–208. DOI: 10.1002/jez.1402330206. 10 11 Holliday CW, Roye DB, Roer RD. 1990. Salinity-induced changes in branchial Na+/K+- ATPase 12 activity and transepithelial potential difference in the brine shrimp Artemia sauna. Journal of 13 Experimental Biology 151:279. 14 15 Hudson DM. 2011. Characteristics contributing to invasiveness of the Asian Shore Crab, 16 Hemigrapsus sanguineus. D. Phil. Thesis. Storrs: University of Connecticut. 17 Hudson DM. 2011. Characteristics contributing to invasiveness of the Asian Shore Crab, 16 Hemigrapsus sanguineus. D. Phil. Thesis. Storrs: University of Connecticut. 17 Hudson DM, Reagan D, Crivello JF. 2016. Community shelter use in response to two benthic 19 decapod predators in the Long Island Sound. PeerJ 4:e2265. DOI: 10.7717/peerj.2265. 20 Hulathduwa YD, Stickle WB, Brown KM. 2007. The effect of salinity on survival, bioenergetics 1 and predation risk in the mud crabs Panopeus simpsoni and Eurypanopeus depressus. Marine 2 Biology 152:363–370. DOI: 10.1007/s00227-007-0687-z. 3 4 Hulme PE. 2009. Trade, transport and trouble: managing invasive species pathways in an era of 5 globalization. Journal of Applied Ecology 46:10–18. DOI: 10.1111/j.1365-2664.2008.01600.x. 6 7 Jones PL., Shulman MJ. 2008. Subtidal-intertidal trophic links: American lobsters [Homarus 8 americanus (Milne-Edwards)] forage in the intertidal zone on nocturnal high tides. Journal of 9 Experimental Marine Biology and Ecology 361:98–103. DOI: 10.1016/j.jembe.2008.05.004. 10 11 Jungblut S. 2017. Ecology and ecophysiology of invasive and native decapod crabs in the southern 12 North Sea. D. Phil. Thesis. Bremen: University of Bremen, Germany. 13 14 Kaplan EL, Meier P. 1958. Nonparametric estimation from incomplete observations. Journal of 15 the American Statistical Association 53:457–481. DOI: 10.1080/01621459.1958.10501452. 16 17 Kassambara A, Kosinski M. 2017. survminer: drawing survival curves using “ggplot2”. R package 18 version 0.4.0. 19 20 Kimball ME, Miller JM, Whitfield PE, Hare JA. 2004. Thermal tolerance and potential distribution 21 of invasive lionfish (Pterois volitans/miles complex) on the east coast of the United States. Marine 22 Ecology Progress Series 283:269–278. DOI: 10.3354/meps283269. 23 Jungblut S. 2017. Ecology and ecophysiology of invasive and native decapod crabs in the southern 12 North Sea. D. Phil. Thesis. Bremen: University of Bremen, Germany. 13 Kaplan EL, Meier P. 1958. Nonparametric estimation from incomplete observations. Journal of 15 the American Statistical Association 53:457–481. DOI: 10.1080/01621459.1958.10501452. 16 1 Kneib RT. 1984. Patterns of invertebrate distribution and abundance in the intertidal salt marsh: 2 causes and questions. Estuaries 7:392. DOI: 10.2307/1351621. 3 4 Koch HJ. 1954. Salinity Preference 7 Cholinesterase and active transport of sodium chloride through the isolated gills 5 of the crab Eriocheir sinensis (M.Edw.). In: Kitching JA ed. Recent Developments in Cell Biology. 6 New York: Academic Press Inc., Publishers, 15–27. 7 8 Kraemer GP, Sellberg M, Gordon A, Main J. 2007. Eight-year Record of Hemigrapsus sanguineus 9 (Asian Shore Crab) Invasion in Western Long Island Sound Estuary. Northeastern Naturalist 10 14:207–224. DOI: 10.1656/1092-6194(2007)14[207:EROHSA]2.0.CO;2. 11 12 Lagerspetz K, Mattila M. 1961. Salinity reactions o fo some fresh- and brackish-water crustaceans. 13 The Biological Bulletin 120:44–53. DOI: 10.2307/1539336. 14 15 Landschoff J, Lackschewitz D, Kesy K, Reise K. 2013. Globalization pressure and habitat change: 16 Pacific rocky shore crabs invade armored shorelines in the Atlantic Wadden Sea. Aquatic 17 Invasions 8:77–87. DOI: 10.3391/ai.2013.8.1.09. 18 19 Lohrer AM, Whitlatch RB. 2002. Interactions among aliens: apparent replacement of one exotic 20 species by another. Ecology 83:719–732. DOI: 10.1890/0012- 21 9658(2002)083[0719:IAAARO]2.0.CO;2. 22 23 Kneib RT. 1984. Patterns of invertebrate distribution and abundance in the intertidal salt marsh: 2 causes and questions. Estuaries 7:392. DOI: 10.2307/1351621. 3 Koch HJ. 1954. Cholinesterase and active transport of sodium chloride through the isolated gills 5 of the crab Eriocheir sinensis (M.Edw.). In: Kitching JA ed. Recent Developments in Cell Biology. 6 New York: Academic Press Inc., Publishers, 15–27. 7 Koch HJ. 1954. Cholinesterase and active transport of sodium chloride through the isolated gills 5 of the crab Eriocheir sinensis (M.Edw.). In: Kitching JA ed. Recent Developments in Cell Biology. 6 New York: Academic Press Inc., Publishers, 15–27. 7 Kraemer GP, Sellberg M, Gordon A, Main J. 2007. Eight-year Record of Hemigrapsus sanguineus 9 (Asian Shore Crab) Invasion in Western Long Island Sound Estuary. Northeastern Naturalist 10 14:207–224. DOI: 10.1656/1092-6194(2007)14[207:EROHSA]2.0.CO;2. 11 12 Lagerspetz K, Mattila M. 1961. Salinity reactions o fo some fresh- and brackish-water crustaceans. 13 The Biological Bulletin 120:44–53. DOI: 10.2307/1539336. 14 Lohrer AM, Whitlatch RB, Wada K, Fukui Y. 2000. Home and away: comparisons of resource 1 utilization by a marine species in native and invaded habitats. Biological Invasions 2:41–57. DOI: 2 10.1023/A:1010069327402. 3 4 Lucu Č, Towle DW. 2003. Na++K+-ATPase in gills of aquatic crustacea. Comparative 5 Biochemistry and Physiology Part A: Molecular & Integrative Physiology 135:195–214. DOI: 6 10.1016/S1095-6433(03)00064-3. 7 8 McDermott J. 1998. The western Pacific brachyuran (Hemigrapsus sanguineus: Grapsidae), in its 9 new habitat along the Atlantic coast of the United States: geographic distribution and ecology. Salinity Preference 7 10 ICES Journal of Marine Science 55:289–298. DOI: 10.1006/jmsc.1997.0273. 11 12 McGaw IJ. 2001. Impacts of habitat complexity on physiology: purple shore crabs tolerate osmotic 13 stress for shelter. Estuarine, Coastal and Shelf Science 53:865–876. DOI: 14 10.1006/ecss.2001.0826. 15 16 McGaw IJ, Naylor E. 1992a. Salinity preference of the shore crab Carcinus maenas in relation to 17 coloration during intermoult and to prior acclimation. Journal of Experimental Marine Biology 18 and Ecology 155:145–159. DOI: 10.1016/0022-0981(92)90059-J. 19 20 McGaw IJ, Naylor E. 1992b. The effect of shelter on salinity preference behaviour of the shore 21 crab Carcinus maenas. Marine Behaviour and Physiology 21:145–152. DOI: 22 10.1080/10236249209378823. 23 Lohrer AM, Whitlatch RB, Wada K, Fukui Y. 2000. Home and away: comparisons of resource 1 utilization by a marine species in native and invaded habitats. Biological Invasions 2:41–57. DOI: 2 10.1023/A:1010069327402. 3 Lucu Č, Towle DW. 2003. Na++K+-ATPase in gills of aquatic crustacea. Comparative 5 Biochemistry and Physiology Part A: Molecular & Integrative Physiology 135:195–214. DOI: 6 10.1016/S1095-6433(03)00064-3. 7 Lucu Č, Towle DW. 2003. Na++K+-ATPase in gills of aquatic crustacea. Comparative 5 Biochemistry and Physiology Part A: Molecular & Integrative Physiology 135:195–214. DOI: 6 10.1016/S1095-6433(03)00064-3. 7 10.1016/S1095-6433(03)00064-3. 7 8 McDermott J. 1998. The western Pacific brachyuran (Hemigrapsus sanguineus: Grapsidae), in its 9 new habitat along the Atlantic coast of the United States: geographic distribution and ecology. 10 ICES Journal of Marine Science 55:289–298. DOI: 10.1006/jmsc.1997.0273. 11 12 8 McDermott J. 1998. The western Pacific brachyuran (Hemigrapsus sanguineus: Grapsidae), in its 9 new habitat along the Atlantic coast of the United States: geographic distribution and ecology. 10 ICES Journal of Marine Science 55:289–298. DOI: 10.1006/jmsc.1997.0273. 11 McGaw IJ, Naylor E. 1992a. Salinity preference of the shore crab Carcinus maenas in relation to 17 coloration during intermoult and to prior acclimation. Journal of Experimental Marine Biology 18 and Ecology 155:145–159. DOI: 10.1016/0022-0981(92)90059-J. 19 McGaw IJ, Naylor E. 1992b. The effect of shelter on salinity preference behaviour of the shore 21 crab Carcinus maenas. Marine Behaviour and Physiology 21:145–152. DOI: 22 10.1080/10236249209378823. 23 1 Neufeld GJ, Holliday CW, Pritchard JB. 1980. Salinity adaption of gill Na, K-ATPase in the blue 2 crab, Callinectes sapidus. Journal of Experimental Zoology 211:215–224. DOI: 3 10.1002/jez.1402110210. 4 5 O’Connor NJ. 2014. Invasion dynamics on a temperate rocky shore: from early invasion to 6 establishment of a marine invader. Biological Invasions 16:73–87. DOI: 10.1007/s10530-013- 7 0504-1. Salinity Preference 7 8 9 Piller SC, Henry RP, Doeller JE, Kraus DW. 1995. A comparison of the gill physiology of two 10 euryhaline crab species, Callinectes sapidus and Callinectes similis: energy production, transport- 11 related enzymes and osmoregulation as a function of acclimation salinity. The Journal of 12 Experimental Biology 198:349–358. 13 14 Rabalais NN, Cameron JN. 1985. Physiological and morphological adaptations of adult Uca 15 subcylindrica to semi-arid environments. The Biological Bulletin 168:135–146. DOI: 16 10.2307/1541179. 17 18 R Core Team. 2017. R: A Language and Environment for Statistical Computing. 19 20 Reisser CE, Forward RB. 1991. Effect of salinity on osmoregulation and survival of a 21 rhizocephalan parasite, Loxothylacus panopaei, and its crab host, Rhithropanopeus harrisii. 22 Estuaries 14:102–106. DOI: 10.2307/1351987. 23 Rabalais NN, Cameron JN. 1985. Physiological and morphological adaptations of adult Uca 15 subcylindrica to semi-arid environments. The Biological Bulletin 168:135–146. DOI: 16 10.2307/1541179. 17 1 Rejmánek M. 2011. Invasiveness. In: Simberloff D, Rejmánek M eds. Encyclopedia of Biological 2 Invasions. Berkeley: University of California Press, 379–385. 3 4 5 Kotta J., Ojaveer H. 2012. Rapid establishment of the alien crab Rhithropanopeus harrisii (Gould) 6 in the Gulf of Riga. Estonian Journal of Ecology 61:293. DOI: 10.3176/eco.2012.4.04. 7 8 Roche DG, Torchin ME, Leung B, Binning SA. 2009. Localized invasion of the North American 9 Harris mud crab, Rhithropanopeus harrisii, in the Panama Canal: implications for eradication and 10 spread. Biological Invasions 11:983–993. DOI: 10.1007/s10530-008-9310-6. 11 12 Rudnick D, Veldhuizen T, Tullis R, Culver C, Hieb K, Tsukimura B. 2005. A life history model 13 for the San Francisco Estuary population of the Chinese mitten crab, Eriocheir sinensis (Decapoda: 14 Grapsoidea). Biological Invasions 7:333–350. DOI: 10.1007/s10530-004-2286-y. 15 16 Shinji J, Strüssmann CA, Wilder MN, Watanabe S. 2009. Short-term responses of the adults of the 17 common Japanese intertidal crab, Hemigrapsus takanoi (Decapoda: Brachyura: Grapsoidea) at 18 different salinities: osmoregulation, oxygen consumption, and ammonia excretion. Journal of 19 Crustacean Biology 29:269–272. DOI: 10.1651/08-2998R.1. 20 21 Siebers D, Leweck K, Markus H, Winkler A. 1982. Sodium regulation in the shore crab Carcinus 22 maenas as related to ambient salinity. Marine Biology 69:37–43. DOI: 10.1007/BF00396958. 23 Roche DG, Torchin ME, Leung B, Binning SA. 2009. Localized invasion of the North American 9 Harris mud crab, Rhithropanopeus harrisii, in the Panama Canal: implications for eradication and 10 spread. Biological Invasions 11:983–993. DOI: 10.1007/s10530-008-9310-6. Rejmánek M. 2011. Invasiveness. In: Simberloff D, Rejmánek M eds. Encyclopedia of Biological 2 Invasions. Berkeley: University of California Press, 379–385. 3 Salinity Preference 7 11 Rudnick D, Veldhuizen T, Tullis R, Culver C, Hieb K, Tsukimura B. 2005. A life history model 13 for the San Francisco Estuary population of the Chinese mitten crab, Eriocheir sinensis (Decapoda: 14 Grapsoidea). Biological Invasions 7:333–350. DOI: 10.1007/s10530-004-2286-y. 15 Shinji J, Strüssmann CA, Wilder MN, Watanabe S. 2009. Short-term responses of the adults of the 17 common Japanese intertidal crab, Hemigrapsus takanoi (Decapoda: Brachyura: Grapsoidea) at 18 different salinities: osmoregulation, oxygen consumption, and ammonia excretion. Journal of 19 Crustacean Biology 29:269–272. DOI: 10.1651/08-2998R.1. 20 Shinji J, Strüssmann CA, Wilder MN, Watanabe S. 2009. Short-term responses of the adults of the 17 common Japanese intertidal crab, Hemigrapsus takanoi (Decapoda: Brachyura: Grapsoidea) at 18 different salinities: osmoregulation, oxygen consumption, and ammonia excretion. Journal of 19 Crustacean Biology 29:269–272. DOI: 10.1651/08-2998R.1. 20 1 Singer JD, Willett JB. 2003. Applied longitudinal data analysis: modeling change and event 2 occurrence. Oxford ; New York: Oxford University Press. 3 4 Sommer MJ, Mantel LH. 1988. Effect of dopamine, cyclic AMP, and pericardial organs on sodium 5 uptake and Na/K-ATPase activity in gills of the green crab Carcinus maenas (L). Journal of 6 Experimental Zoology 248:272–277. DOI: 10.1002/jez.1402480305. 7 8 Teal JM. 1958. Distribution of fiddler crabs in Georgia salt marshes. Ecology 39:185–193. DOI: 9 10.2307/1931862. 10 11 Therneau T. 2015.Survival: a package for survival analysis in S. R package version 2.38. Available 12 at http://cran.r-project.org/package=survival 13 14 Thomas NJ, Lasiak TA, Naylor E. 1981. Salinity preference behaviour in Carcinus. Marine 15 Behaviour and Physiology 7:277–283. DOI: 10.1080/10236248109386988. 16 17 Towle DW. 1997. Molecular approaches to understanding salinity adaptation of estuarine animals. 18 American Zoologist 37:575–584. DOI: 10.1093/icb/37.6.575. 19 20 Towle DW, Kays WT. 1986. Basolateral localization of Na+ + K+-ATPase in gill epithelium of 21 two osmoregulating crabs, Callinectes sapidus and Carcinus maenas. Journal of Experimental 22 Zoology 239:311–318. DOI: 10.1002/jez.1402390302. 23 Singer JD, Willett JB. 2003. Applied longitudinal data analysis: modeling change and event 2 occurrence. Oxford ; New York: Oxford University Press. 3 Sommer MJ, Mantel LH. 1988. Effect of dopamine, cyclic AMP, and pericardial organs on sodium 5 uptake and Na/K-ATPase activity in gills of the green crab Carcinus maenas (L). Journal of 6 Experimental Zoology 248:272–277. DOI: 10.1002/jez.1402480305. 7 Thomas NJ, Lasiak TA, Naylor E. 1981. Salinity preference behaviour in Carcinus. Marine 15 Behaviour and Physiology 7:277–283. DOI: 10.1080/10236248109386988. 16 Towle DW. 1997. Salinity Preference 7 Molecular approaches to understanding salinity adaptation of estuarine animals. 18 American Zoologist 37:575–584. DOI: 10.1093/icb/37.6.575. 19 Towle DW, Kays WT. 1986. Basolateral localization of Na+ + K+-ATPase in gill epithelium of 21 two osmoregulating crabs, Callinectes sapidus and Carcinus maenas. Journal of Experimental 22 Zoology 239:311–318. DOI: 10.1002/jez.1402390302. 23 1 Tsai J-R, Lin H-C. 2007. V-type H+-ATPase and Na+,K+-ATPase in the gills of 13 euryhaline crabs 2 during salinity acclimation. Journal of Experimental Biology 210:620–627. DOI: 3 10.1242/jeb.02684. 4 5 d’Udekem d’Acoz C, Faasse M. 2002. De huidige status van Hemigrapsus sanguineus (de Haan, 6 1835) en H. penicillatus (de Haan, 1835) in de noordelijke Atlantische Oceaan, in het bijzonder in 7 Nederland, met opmerkingen over hun biologie (Crustacea, Decapoda, Brachyura). Het Zeepaard 8 62:101–115. 9 10 Urbina M, Paschke K, Gebauer P, Chaparro OR. 2010. Physiological energetics of the estuarine 11 crab Hemigrapsus crenulatus (Crustacea: Decapoda: Varunidae): responses to different salinity 12 levels. Journal of the Marine Biological Association of the United Kingdom 90:267–273. DOI: 13 10.1017/S0025315409990889. 14 15 Urzúa Á, Urbina MA. 2017. Ecophysiological adaptations to variable salinity environments in the 16 crab Hemigrapsus crenulatus from the Southeastern Pacific coast: sodium regulation, respiration 17 and excretion. Comparative Biochemistry and Physiology Part A: Molecular & Integrative 18 Physiology 210:35–43. DOI: 10.1016/j.cbpa.2017.05.010. 19 20 Weihrauch D, Morris S, Towle DW. 2004. Ammonia excretion in aquatic and terrestrial crabs. 21 Journal of Experimental Biology 207:4491–4504. DOI: 10.1242/jeb.01308. 22 23 Tsai J-R, Lin H-C. 2007. V-type H+-ATPase and Na+,K+-ATPase in the gills of 13 euryhaline crabs 2 during salinity acclimation. Journal of Experimental Biology 210:620–627. DOI: 3 10.1242/jeb.02684. 4 5 d’Udekem d’Acoz C, Faasse M. 2002. De huidige status van Hemigrapsus sanguineus (de Haan, 6 1835) en H. penicillatus (de Haan, 1835) in de noordelijke Atlantische Oceaan, in het bijzonder in 7 Nederland, met opmerkingen over hun biologie (Crustacea, Decapoda, Brachyura). Het Zeepaard 8 62:101–115. 9 d’Udekem d’Acoz C, Faasse M. 2002. De huidige status van Hemigrapsus sanguineus (de Haan, 6 1835) en H. penicillatus (de Haan, 1835) in de noordelijke Atlantische Oceaan, in het bijzonder in 7 Nederland, met opmerkingen over hun biologie (Crustacea, Decapoda, Brachyura). Het Zeepaard 8 62:101–115. 9 Urbina M, Paschke K, Gebauer P, Chaparro OR. 2010. Physiological energetics of the estuarine 11 crab Hemigrapsus crenulatus (Crustacea: Decapoda: Varunidae): responses to different salinity 12 levels. Journal of the Marine Biological Association of the United Kingdom 90:267–273. Salinity Preference 7 DOI: 13 10.1017/S0025315409990889. 14 Weihrauch D, Morris S, Towle DW. 2004. Ammonia excretion in aquatic and terrestrial crabs. 21 Weihrauch D, Morris S, Towle DW. 2004. Ammonia excretion in aquatic and terrestrial crabs. 21 Journal of Experimental Biology 207:4491–4504. DOI: 10.1242/jeb.01308. 22 23 Weis JS. 2010. The role of behavior in the success of invasive crustaceans. Marine and Freshwater 1 Behaviour and Physiology 43:83–98. DOI: 10.1080/10236244.2010.480838. 2 3 Williams AB, McDermott JJ. 1990. An eastern United States record for the western Indo-Pacific 4 crab, Hemigrapsus sanguineus (Crustacea: Decapoda: Grapsidae). Proceedings of the Biological 5 Society of Washington 103:108–109. 6 7 Wolf B, Kiel E, Hagge A, Krieg H-J, Feld CK. 2009. Using the salinity preferences of benthic 8 macroinvertebrates to classify running waters in brackish marshes in Germany. Ecological 9 Indicators 9:837–847. DOI: 10.1016/j.ecolind.2008.10.005. 10 11 Young AM. 1978. Desiccation tolerances for three hermit crab species Clibanarius vittatus (Bosc), 12 Pagurus pollicaris Say and P. longicarpus Say (Decapoda, Anomura) in the North Inlet Estuary, 13 South Carolina, U.S.A. Estuarine and Coastal Marine Science 6:117–122. DOI: 10.1016/0302- 14 3524(78)90047-6. 15 16 Young AM. 1979. Osmoregulation in three hermit crab species, Clibanarius vittatus (Bosc), 17 Pagurus longicarpus Say and P. pollicaris Say (Crustacea: Decapoda; Anomura). Comparative 18 Biochemistry and Physiology Part A: Physiology 63:377–382. DOI: 10.1016/0300- 19 9629(79)90606-6. 20 Weis JS. 2010. The role of behavior in the success of invasive crustaceans. Marine and Freshwater 1 Behaviour and Physiology 43:83–98. DOI: 10.1080/10236244.2010.480838. 2 Williams AB, McDermott JJ. 1990. An eastern United States record for the western Indo-Pacific 4 crab, Hemigrapsus sanguineus (Crustacea: Decapoda: Grapsidae). Proceedings of the Biological 5 Society of Washington 103:108–109. 6 Williams AB, McDermott JJ. 1990. An eastern United States record for the western Indo-Pacific 4 crab, Hemigrapsus sanguineus (Crustacea: Decapoda: Grapsidae). Proceedings of the Biological 5 Society of Washington 103:108–109. 6 Wolf B, Kiel E, Hagge A, Krieg H-J, Feld CK. 2009. Using the salinity preferences of benthic 8 macroinvertebrates to classify running waters in brackish marshes in Germany. Ecological 9 Indicators 9:837–847. DOI: 10.1016/j.ecolind.2008.10.005. 10 Young AM. 1978. Desiccation tolerances for three hermit crab species Clibanarius vittatus (Bosc), 12 Pagurus pollicaris Say and P. longicarpus Say (Decapoda, Anomura) in the North Inlet Estuary, 13 South Carolina, U.S.A. Estuarine and Coastal Marine Science 6:117–122. DOI: 10.1016/0302- 14 3524(78)90047-6. 15 16 Young AM. 1979. Osmoregulation in three hermit crab species, Clibanarius vittatus (Bosc), 17 Pagurus longicarpus Say and P. Zacherl D, Gaines SD, Lonhart SI. 2003. The limits to biogeographical distributions: insights from 1 the northward range extension of the marine snail, Kelletia kelletii (Forbes, 1852). Journal of 2 Biogeography 30:913–924. DOI: 10.1046/j.1365-2699.2003.00899.x. 3 Salinity Preference 7 pollicaris Say (Crustacea: Decapoda; Anomura). Comparative 18 Biochemistry and Physiology Part A: Physiology 63:377–382. DOI: 10.1016/0300- 19 9629(79)90606-6. 20 21 4
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Following Mixed Tree Nut Biscuit Challenge, Are the Nuts Still Included in the Diet?
SN Comprehensive Clinical Medicine
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ERROR: type should be string, got "https://doi.org/10.1007/s42399-020-00484-w\nSN Comprehensive Clinical Medicine (2020) 2:2208–2213 MEDICINE MEDICINE To the Editor Undiagnosed food allergy without known reaction to the\navoided food could result in elimination of the suspected food\nfrom a child’s diet [1]. Performing OFC to individual tree nuts\nis time consuming and impractical. Following a negative OFC\nchildren need to regularly include that food in their diet with\nevidence showing this may help to maintain tolerance to that\nfood [2]. The patients in this study are from a retrospective review of\npatients with a negative OFC to mixed tree nut biscuit per-\nformed at Princess Margaret Hospital (PMH), Western\nAustralia between 2016 and 2018. The tree nuts used in the OFC are almond, Brazil nut,\nmacadamia, cashew, pistachio, walnut, pecan, hazel nut, pine\nnut, and coconut. Mixed tree nut biscuit OFC included at least\n2 of the above nuts. The cohort of patients had predominantly negative or low\npositive skin prick test (< 6-mm mean skin prick test weal\ndiameter). Although most of the patients had a negative skin\nprick test (SPT), the challenge was done in hospital as families\nwere anxious or reluctant to introduce the nuts at home. Abstract We studied the introduction rate after a negative challenge to mixed tree nut biscuit. This is a retrospective review of patients who\nunderwent and passed mixed tree nut biscuit challenges performed at Princess Margaret Hospital (PMH) between 2016 and 2018. Follow-up phone calls were made to families to ascertain if the tree nuts included in the tree nut biscuit were still included in the\nchild’s diet 1 to 3 years following negative oral food challenge (OFC). A total of 162 children underwent mixed tree nut biscuit\nchallenge between 2016 and 2018 at Princess Margaret Hospital, Perth, Western Australia. A total of 141 (87%) passed mixed\ntree nut biscuit challenge. Of the 133 children that were contacted (8 children could not be contacted), 104 children still included\nsome or all of the challenge nuts in the child’s diet; with 24 children completely eliminating the challenge nuts (18%), 5 children\neliminated some of the challenge nuts (3.5%). We found a high introduction rate (82%); however, some families may require\nmore support to maintain the tree nuts in the child’s diet following a negative OFC. Keywords Mixed tree nut challenge Following Mixed Tree Nut Biscuit Challenge, Are the Nuts Still\nIncluded in the Diet? Benedicta Itotoh1\n& Ingrid Roche1 & Catherine Power1 Accepted: 24 August 2020\n# The Author(s) 2020\n/ Published online: 7 September 2020 1\nDepartment of Immunology, Perth Children’s Hospital,\nNedlands, Western Australia, Australia Introduction We studied the dietary introduction rate of tree nuts following\na negative OFC. Most of the children avoided tree nuts be-\ncause they were allergic to other foods or sensitized to tree\nnuts with no known clinical reaction. Some were avoiding tree\nnuts because another family member has a nut allergy. The SPT was performed and read as per the published\nguidelines of the Australasian Society of Clinical\nImmunology and Allergy [3]. The SPT size on the day of\nthe challenge was recorded. This article is part of the Topical Collection on Medicine\n* Benedicta Itotoh\nbenedicta.itotoh@health.wa.gov.au\n1\nDepartment of Immunology, Perth Children’s Hospital,\nNedlands, Western Australia, Australia The treating physician decides what nuts were included in\nthe biscuit, and the patient’s family baked and provided the\nmixed tree nut biscuit according to the recipe provided by the\nPMH Immunology Department. The biscuit was then admin-\nistered in a 5-step procedure starting with 1/16, 1/8, 1/4, 1/2,\nand the reminder of the biscuit given at 15-min intervals if\nchallenge was performed in the outpatient department * Benedicta Itotoh\nbenedicta.itotoh@health.wa.gov.au Materials and Methods To the Editor This article is part of the Topical Collection on Medicine This article is part of the Topical Collection on Medicine * Benedicta Itotoh\nbenedicta.itotoh@health.wa.gov.au SN Compr. Clin. Med. (2020) 2:2208–2213 2209 Table 1\nPossible factors associated with failed introduction following\nnegative OFC to three nuts\nSuccessful\n(eating all nuts\nPartial (eating\nsome nuts)\nUnsuccessful\n(not eating any\nof the nuts)\nTotal\n104\n5\n24\nGender\nMale\n65\n3\n8\nFemale\n39\n2\n16\nAge range\n1 year\n5 months to\n17 years\n7 months\n1 year\n8 months to\n10 years\n4 months\n1 year\n8 months to\n16 years\nSymptoms to\nchallenged nuts\nfollowing\nsuccessful OFC\n0\n1\nHives to hazel\nnut\n1\nRespiratory\nsymptoms Table 1\nPossible factors associated with failed introduction following\nnegative OFC to three nuts Data was obtained from electronic patient records as well\nas patient charts and used in strictly anonymous form, accord-\ning to the code of conduct for medical research approved by\nthe hospital’s Medical Ethical Committee (Child and\nAdolescent Health Service Safety and Quality Committee). Results A total of 162 children underwent mixed tree nut biscuit OFC\nbetween 2016 and 2018 at PMH. A total of 141 passed mixed\ntree nut biscuit challenge (87%). The majority of OFCs were\nconducted in the OPD (70.4%). All 141 patient charts were\nexamined with follow-up phone calls made to families to as-\ncertain if the nuts were still included in the child’s diet 1–\n3 years following the OFC. Eight families could not be\ncontacted. The majority were male (55%). Median age at chal-\nlenge was 8 years and 5 months (range 1 year and 7 months to\n17 years and 7 months). Twenty-seven children were admin-\nistered six nut challenge, 40 underwent 5 nut challenge, 38\nhad 4 nut challenge, 23 had 3 nut challenge, and 13 patients\nhad 2 nut challenge. (OPD) or as a 7-step procedure starting with 1/64, 1/32, 1/16,\n1/8, 1/4, 1/2, and reminder of the biscuit given at 20-min\nintervals if challenge was performed in the day procedure unit\n(DPU). The decision to either perform the challenge in the\nOPD or DPU was determined by the treating physician based\non the clinical risk of allergic reaction. Eight grams of each\nchallenge nut were included in the biscuit. Of the 133 families that were contacted, 104 families still\nincluded some or all of the challenge nuts in the child’s diet. Twenty-four patients completely eliminated the challenge\nnuts (18%) and 5 patients eliminated some of the challenge\nnuts (3.5%). Signed consent for the challenge was obtained from the\nparents prior to the challenge. Patients were recorded as a positive OFC if there were\nobjective signs of an IgE-mediated reaction as follows: angio-\nedema, generalized skin erythema, stridor, cough, wheeze, at\nleast 3 or more noncontact urticaria persisting for 5 min or\nmore, rhinoconjunctivitis, abdominal pain, vomiting, and hy-\npotension [4]. All patients had follow-up phone contact 2–\n4 weeks following the OFC. The patients were termed tolerant\nif they had a negative OFC and were tolerating the nuts at their\n2–4-week follow-up phone calls. Patients that passed the chal-\nlenge were advised to continue eating the nuts included in the\nbiscuit regularly (at least weekly). Discussion Possible factors influencing the introduction of the challenge\nnuts in the diet are shown in Table 1. Other patient character-\nistics with successful, partial, and unsuccessful challenge nut\ndietary introduction are shown in Table 1. There are no statis-\ntically relevant differences between the three groups. Fig. 1 Reasons for eliminating\nnuts from diet Fig. 1 Reasons for eliminating\nnuts from diet 2210 SN Compr. Clin. Med. (2020) 2:2208–2213 Table 2\nTree nuts included in biscuit, rate of introduction, and\nelimination from diet\nNuts included in\nmixed tree nut\nbiscuit\nNuts eliminated\nfrom diet following\nOFC\nNuts maintained\nin diet following\nOFC\nAlmond\n97\n21\n77\nBrazil nut\n97\n21\n76\nMacadamia 114\n21\n76\nHazel nut\n66\n13\n53\nPecan\n17\n1\n16\nWalnut\n76\n17\n59\nCashew\n50\n9\n41\nPistachio\n6\n1\n5\nPine nut\n23\n5\n18\nCoconut Table 2\nTree nuts included in biscuit, rate of introduction, and\nelimination from diet The other family describes exacerbation of the child’s asthma\nto all nuts. However, there was no clinical correlation between\nexposure to nuts and exacerbation of asthma with the elimination\nof nuts having no impact on the asthma symptoms. This patient\nwas challenged to almond, Brazil nut, walnut (negative SPT),\nhazel nut (2 × 2 mm SPT), and macadamia nut (1 × 1mm SPT). Of the 5 children whose families partially introduced the\ntree nuts, we note the following: The first child is the same child that excluded hazel nut\nbecause she had hives to hazel nut. She retained almond,\nBrazil, macadamia, and pine nuts in her diet. Two children ate almond only for no defined reason. One\nchild had challenge to almond, Brazil nut, walnut, and\nmacadamia, while the other child had challenge to almond,\nmacadamia, Brazil, hazel, and pine nuts. One child retained 2 of the 4 nuts included in their biscuit\nchallenge (hazel and macadamia nuts) with the remaining nuts\n(brazil and cashew nuts) excluded as this child is reported to\nbe a “fussy eater” by parents. The reasons for the 24 families who completely eliminated\nthe challenge nuts from the child’s diet, in spite of a negative\nOFC, are depicted in Fig. 1. The last child retained 3 of the 5 nuts included in their biscuit\nchallenge (almond, hazel, and macadamia nuts) with the re-\nmaining nuts (brazil and walnut) excluded based on taste. Review of Fig. Fig. 2 SPT prior to OFC Discussion 1 shows 3 children being scared to continue\neating the challenge nuts; 4 children being diagnosed with\nanother nut allergy that was not included in the OFC so the\nfamily choose to avoid all nuts; 1 child being busy with final\nyear of high school; and another child having general poor\nhealth. Average number of tree nuts in challenges was four. Macadamia was the most frequently included tree nut in the\nOFC. Table 2 is a representation of the tree nuts included in\nthe biscuit and tree nuts eliminated or maintained in the diet\nfollowing OFC. Just as macadamia, almond, and Brazil nuts\nwere most likely to be maintained in the diet, they also had\nhigh rates of elimination from diet which may be a reflection\nof the frequency these nuts were included in the OFC. More boys (90%) than girls (83%) had partially or success-\nfully introduced the nuts. Of those that continued to eat the\nnuts, all but 2 families reported there was no reactions to any\nof the nuts. One family reported that the child developed hives\nsecondary to hazel nut exposure. This child had OFC per-\nformed which included almond, hazel nut, Brazil nut,\nmacadamia, and pine nut with the following SPTs: Almond,\nBrazil nut, and macadamia are all negative SPT. Hazel nut\nSPT was 4 × 4 mm. Pine nut SPT was 3 × 3 mm. SPT ranged from negative to 7 × 5 mm prior to the test. SPT was done for all nuts included in the biscuit. Figure 2 is a\nrepresentation of the SPT performed prior to the challenge. Previous reaction to tree nuts included in the biscuit range\nfrom none (sensitized only with no previous exposure) to ob-\njective symptoms as well as nonobjective symptoms. Fig. 2 SPT prior to OFC Fig. 2 SPT prior to OFC 2211 SN Compr. Clin. Med. Discussion (2020) 2:2208–2213 Table 3\nSymptoms to nuts included in biscuits prior to OFC, SPT on day, and outcome on follow-up\nPatients (age and gender)\nSymptoms to nuts in biscuits\nprior to OFC\nNuts included in biscuits\nSPT to nuts on the\nday of OFC\nOutcome on follow-up\nMale\n8 years 6 months\nUpper respiratory symptoms\nAlmond, pine nut, macadamia\nNegative to all\nAll nuts maintained in diet\nMale\n2 years 10 months\nGeneralized rash\nAlmond, Brazil nut, cashew\nNegative to all\nAll nuts maintained in diet\nFemale 12 years 1 month\nThroat tightness\nAlmond, hazel nut, Brazil nut,\ncashew, macadamia\nNegative to all\nNone of the nuts maintained\nin diet, no reason given\nFemale 13 years 6 months\nUrticaria to products labeled\nmay contain traces\nAlmond, Brazil nut, walnut,\nMacadamia\nAlmond (3 × 4 mm)\nBrazil nut (2 × 4 mm)\nwalnut negative\nMacadamia(3 × 3 mm)\nAll nuts maintained in diet\nFemale 3 years 2 months\nFacial rash, itchy tongue\nAlmond, Brazil nut, cashew,\nwalnut, macadamia\nNegative to all\nAll nuts maintained in diet\nMale\n13 years 10 months\nFacial erythema to pine nuts\nBrazil nut, pine nut, macadamia\nBrazil nut 4 × 5 mm\nMacadamia 2 × 3 mm\nPine nut negative\nAll nuts maintained in diet 3\nSymptoms to nuts included in biscuits prior to OFC, SPT on day, and outcome on follow-up Of all the 139 who had negative OFC, 6 describe symp-\ntoms to the challenge nuts prior to the challenge. Characteristics of this group are reflected in Table 3. Our study reveals that there is a high success rate of passing\nthe mixed tree nut OFC with the majority of families continu-\ning to eat the nuts. Recurrence of tree nut allergy following\nOFC has not been reported to date. The presence of asthma, eczema, allergic rhinitis, and other\nfood allergies was determined in out-patient clinic consulta-\ntion before the OFC. This information is detailed in Table 4. It will be interesting to follow up children that failed the\nintroduction of the challenge nuts to note if immunologic tol-\nerance is maintained. Most of the patients that passed the challenge had multiple\nfood allergies. There were 256 cases of documented single or\nmultiple food allergies. Conclusion There are some limitations to our study. It is a retrospective\nstudy which relied on the documentation of the treating physi-\ncian. We also note the majority of patients had negative or low\npositive SPT which is not representative of patients with true tree\nnut allergy. The families prepared the tree nut biscuit as per our\nguidelines though this is not standardized with all tested tree nuts. Our data show that open mixed tree nut OFC is useful in\nexcluding multiple tree nut allergies in children with low sus-\npicion of clinical allergy. Some families will require more\nsupport to maintain the challenge nuts in the child’s diet fol-\nlowing a negative OFC. Table 4\nPatient characteristics for successful, partially successful, and\nunsuccessful introduction of tree nuts\nSuccessful\nPartially successful\nUnsuccessful\nEczema\n25\n1\n7\nAsthma\n25\n0\n5\nAllergic rhinitis\n21\n1\n4\nOther tree nut allergy\n50\n3\n5\nPeanut allergy\n53\n3\n8\nOther food allergy\n111\n2\n21 Table 4\nPatient characteristics for successful, partially successful, and\nunsuccessful introduction of tree nuts Authors’ Contribution Authors 1, 2, and 3 contributed to the conception\nand design of the work and acquisition, analysis, and interpretation of\ndata and also contributed to drafting the work and revising it critically for\nimportant intellectual content as well as final approval of the version to be\npublished. All authors agree to be accountable for all aspects of the work\nin ensuring that questions related to the accuracy or integrity of any part of\nthe work are appropriately investigated and resolved. Discussion Of these 64 are allergic to peanuts, 58\nallergic to other tree nuts not included in the OFC, 47 allergic\nto egg, 18 allergic to cow’s milk, and 69 allergic to other foods\n(wheat, other legumes, sesame, sea food, and kiwi fruit). To further improve rates of introduction of the tree nuts\nfollowing negative OFC, we should encourage families to\nmaintain the nuts in the child’s diet. Contact between families\nand the Immunology Department should be streamlined to\nallow contemporaneous contact at the time of a possible reac-\ntion to the challenge nuts. Previous study by Van Der Valk et al. looked at introduc-\ntion of cashew nut following a negative OFC at 6 months with\na successful introduction rate of 43.3% [5]. Our study found a\ncombined total of successful and partial introduction rate of\n82% for all challenge nuts. Compliance with Ethical Standards Conflict of Interest\nThe authors declare that they have no conflict of\ninterest. 2212 SN Compr. Clin. Med. (2020) 2:2208–2213 patient records as well as patient charts and used in strictly anonymous\nform. Verbal consent was obtained from the parent prior to commencing\nthe phone interview. Ethical Approval\nData was obtained from electronic patient records as\nwell as patient charts and used in strictly anonymous form, according to\nthe code of conduct for medical research approved by the hospital’s\nMedical Ethical Committee (Child and Adolescent Health Service\nSafety and Quality Committee). patient records as well as patient charts and used in strictly anonymous\nform. Verbal consent was obtained from the parent prior to commencing\nthe phone interview. Appendix Informed Consent\nSigned consent for the challenge was obtained from\nthe parents prior to the challenge. In accordance with the hospital’s guide-\nlines for use of patient’s records, data was obtained from electronic Recipe for mixed tree nut biscuit. 1.\nDiagnosing and managing food allergy in children Holloway,\nEdward; Fox, Adam, Fitzsimons, Roisin. Practitioner; London Vol.\n255, Iss. 1741. 2213 SN Compr. Clin. Med. (2020) 2:2208–2213 Open Access This article is licensed under a Creative Commons\nAttribution 4.0 International License, which permits use, sharing, adap-\ntation, distribution and reproduction in any medium or format, as long as\nyou give appropriate credit to the original author(s) and the source, pro-\nvide a link to the Creative Commons licence, and indicate if changes were\nmade. The images or other third party material in this article are included\nin the article's Creative Commons licence, unless indicated otherwise in a\ncredit line to the material. If material is not included in the article's\nCreative Commons licence and your intended use is not permitted by\nstatutory regulation or exceeds the permitted use, you will need to obtain\npermission directly from the copyright holder. To view a copy of this\nlicence, visit http://creativecommons.org/licenses/by/4.0/. 2. Fleischer DM, Conover-Walker MK, Christie L, Burks AW, Wood\nRA. The natural progression of peanut allergy: resolution and the\npossibility of recurrence. J Allergy Clin Immunol St Louis. 2003;112(1):183–9. https://doi.org/10.1067/mai.2003.1517. 3. Australasian Society of Clinical Immunology and Allergy. Skin\nPrick Testing Working Party. Skin Prick testing for the diagnosis\nof allergic disease. Updated 2020. Available at https://\nwww.allergy.org.au/ASCIA_HP_SPT_Guide_2020 4. Thalayasingam M, Noble V, Franzmann A, O’Sullivan M. Outcome\nof mixed nut biscuit challenge in low risk patients who are on tree nut\nexclusion diet. Paediatr Allergy Immunol. 2015. https://doi.org/10. 1111/pai.12437. 5. van der Valk JPM, van Wijk RG, Dubois AEJ, de Groot H, de Jong\nNW. Failure of introduction of cashew nut after a negative oral food\nchallenge test in children. Paediatr Allergy Immunol. 2016. https://\ndoi.org/10.1111/PAI.12591. References Publisher’s Note\nSpringer Nature remains neutral with regard to juris-\ndictional claims in published maps and institutional affiliations."
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BIOFILMELE FUNGICE – PROVOCARE ACTUALĂ LA NIVEL MONDIAL
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Introducere Biofilmele microbiene constituie în prezent o problemă de sănătate publică care afectează populația din toate țările, indiferent de gradul de dezvoltare al acestora. Biofilmele microbiene constituie în prezent o problemă de sănătate publică care afectează populația din toate țările, indiferent de gradul de dezvoltare al acestora. ț g Conceptul de biofilm reprezintă o nouă paradigmă în microbiologie: 99% din bacteriile de pe Terra trăiesc asociate în consorţii complexe, ataşate suprafeţelor, iar abordarea lor indică noi perspective de cercetare [1,2]. Studiul biofilmelor devine astfel un domeniu interdisciplinar şi multidisciplinar, antrenând microbiologi, i i i di i l i i li ti î l ți i i i ti i i hi i ti fi i i i t ti i i Conceptul de biofilm reprezintă o nouă paradigmă în microbiologie: 99% din bacteriile de pe Terra trăiesc asociate în consorţii complexe, ataşate suprafeţelor, iar abordarea lor indică noi perspective de cercetare [1,2]. Conceptul de biofilm reprezintă o nouă paradigmă în microbiologie: 99% din bacteriile de pe Terra trăiesc asociate în consorţii complexe, ataşate suprafeţelor, iar abordarea lor indică noi perspective de cercetare [1,2]. Studiul biofilmelor devine astfel un domeniu interdisciplinar şi multidisciplinar, antrenând microbiologi, ingineri, medici, ecologi, specialiști în evoluționism, microscopie, geneticieni, chimiști, fizicieni, matematicieni, igienişti, toxicologi din întreaga lume [3,4]. Studiul biofilmelor devine astfel un domeniu interdisciplinar şi multidisciplinar, antrenând microbiologi, ingineri, medici, ecologi, specialiști în evoluționism, microscopie, geneticieni, chimiști, fizicieni, matematicieni, igienişti, toxicologi din întreaga lume [3,4]. Biofilmele au subminat graniţa biologică între eucariote şi procariote [5]. Aceste consorții reprezintă niște structuri complexe de microorganisme legate în mod ireversibil de suprafeţe solide inerte sau vii şi înconjurate de o matrice polimerică organică amorfă, fiind o secreție extracelulară a microorganismelor – substanțe poli- merice extracelulare. Autorii studiilor definesc biofilmul microbian ca o structură tridimensională care aderă atât la suprafețele vii, cât și la cele inerte, fiind constituită din agregate de celule microbiene (proteine şi ADN) încorporate într-o matrice polimerică, extracelulară, exopolizaharidică, autosecretată [6,7]. Aderarea microorganismelor la o suprafaţă şi dezvoltarea biofilmului reprezintă una dintre „strategiile” de supravieţuire a acestora la acțiunea factorilor de mediu. În natură biofilmele sunt răspândite pretutindeni fiind constituite din bacterii, protozoare, actinomicete, ciuperci și alge microscopice aflate în relaţii de mutualism şi comensalism, care se exprimă prin cooperarea reciproc avantajoasă pentru consorţi, cu referire la hrană, apă, protecţie, transport etc. [8]. CZU: 579.61 BIOFILMELE FUNGICE – PROVOCARE ACTUALĂ LA NIVEL MONDIAL Olga BURDUNIUC Olga BURDUNIUC Agenţia Naţională pentru Sănătate Publică, Universitatea de Stat de Medicină şi Farmacie „Nicolae Testemiţanu” g ţ ţ p Universitatea de Stat de Medicină şi Farmacie „Nicolae Testemiţanu” În prezenta lucrare sunt analizate cele mai relevante publicații din literatura medicală selectate printr-o cercetare utili- zând bazele de date PubMed, EMBASE, HINARI și site-urile web ale OMS, CDC privind unul dintre factorii de viru- lenţă a fungilor precum formarea biofilmelor. Scopul acestui review este de a furniza informație științifică actuală refe- ritore la acest subiect. Au fost revizuite un șir de studii și s-a constatat că ambele tipuri de fungi – atît levuriformi, cât și filamentoși – pot adera la suprafețe biotice și abiotice, dezvoltându-se în comunități extrem de organizate, rezistente la preparatele antimicotice și la factorii de mediu. p p ș Cuvinte-cheie: fungi, biofilme, persistenţă, rezistență la antimicotice. FUNGAL BIOFILMS – CURRENT CHALLENGE WORLDWIDE This paper is a literature review that analyzes the most relevant publications in the medical literature, selected through a search in databases such as PubMed EMBASE, HINARI, WHO and CDC websites regarding one of the fungal virulence factors - biofilm formation. The purpose of this review is to provide up-to-date scientific information on this topic. In carrying out these objectives, a series of studies were reviewed and it was found that both yeasts and filamentous fungi can adhere to biotic and abiotic surfaces, developing in highly organized communities, resistant to antifungal drugs and environmental factors. Keywords: fungi, biofilms, persistence, resistance to antifungals. S T U D I A U N I V E R S I T A T I S M O L D A V I A E S T U D I A U N I V E R S I T A T I S M O L D A V I A E S T U D I A U N I V E R S I T A T I S M O L D A V I A E Revist= [tiin\ific= a Universit=\ii de Stat din Moldova, 2020, nr.1(131) CZU: 579.61 BIOFILMELE FUNGICE – PROVOCARE ACTUALĂ LA NIVEL MONDIAL CZU: 579.61 Introducere Natura prezintă biofilmele, adesea multispecifice, de aceea această formă de existență a fost studiată pe larg în ultimul timp. Cercetătorii au evidențiat în structura biofilmelor agenți microbieni cu expresie genetică și fenotipică și rată de multiplicare diferită de ale celor aflați în stare planctonică. Biofilmele sunt considerate ca un stil de viață universal pentru supraviețuirea microbilor în acțiunea preparatelor antimicotice și predomină în natură comparativ cu celulele planctonice [9,10]. Biofilmele au fost studiate pe larg în ultimul timp și s-a demonstrat implicarea acestora în dezvoltarea unui spectru larg de maladii infecțioase, inclusiv fungice. Totodată, biofilmelor le datorăm atât rezistenţa la antimi- crobiene, mecanisme de apărare a organismului, precum și persistenţa portajului [10]. 100 Seria “{tiin\e reale [i ale naturii” {tiin\e Biologice ISSN 1814-3237 Implicarea biofilmelor microbiene în apariția infecțiilor persistente și evoluția microorganismelor rezistente la antimicrobiene este astăzi o certitudine. Biofilmele fungice au fost raportate a fi de până la 1000 de ori mai rezistente la antifungice decât celulele planctonice, dar mecanismul acestei rezistențe rămâne neclar [10–12]. Studiile recente subliniază că o bună parte din patologia infecțioasă este generată și/sau întreținută de bio- filme acestea fiind implicate în cel puțin 60% din totalul cazurilor de infecții cronice sau recurente [12] Implicarea biofilmelor microbiene în apariția infecțiilor persistente și evoluția microorganismelor rezistente la antimicrobiene este astăzi o certitudine. Biofilmele fungice au fost raportate a fi de până la 1000 de ori mai rezistente la antifungice decât celulele planctonice, dar mecanismul acestei rezistențe rămâne neclar [10–12]. rezistente la antifungice decât celulele planctonice, dar mecanismul acestei rezistențe rămâne neclar [10–12]. Studiile recente subliniază că o bună parte din patologia infecțioasă este generată și/sau întreținută de bio- filme, acestea fiind implicate în cel puțin 60% din totalul cazurilor de infecții cronice sau recurente [12]. Studiile recente subliniază că o bună parte din patologia infecțioasă este generată și/sau întreținută de bio- filme, acestea fiind implicate în cel puțin 60% din totalul cazurilor de infecții cronice sau recurente [12]. Celulele persistente din biofilme formează cel puțin 1% din populație. Acestea sunt celule latente, care asi- gură supraviețuirea chiar și după un curs extensiv și pe termen lung de terapie antifungică, acest aspect şi duce la recurență și recidivă [14]. Fungii formează biofilme pentru cooperare metabolică, dobândirea de noi trăsături genetice și creșterea re- zistenței la factorii de mediu. Actualmente se atestă creșterea ponderii infecțiilor fungice. Introducere Medicina modernă a furnizat fungilor multe nișe, cum ar fi catetere, șunturi, tuburi, implanturi, lentile de contact, proteze și dis- pozitive protetice. Dispozitivele sunt colonizate de fungi și formează biofilme pe suprafețele abiotice [12,15]. Biofilmele au fost în atenția multor savanți renumiți, care descriu procesul de formare a acestora într-o manieră secvențială: (a) aderența și adsorbția. Fixarea iniţială: începe cu o ataşare reversibilă de o suprafaţă a microorganismelor. Aceşti primi colonişti aderă slab la suprafaţă, legându-se prin forţe Van der Waals. Ataşarea ireversibilă: dacă coloniştii nu sunt îndepărtaţi imediat de pe suprafaţă, ei se pot ancora mai ferm, folosindu-se de structurile de adeziune celulară, cum sunt pilii; (b) stadiul intermediar (maturizarea I) are o activitate metabolică maximă. Matricea polimerică extracelulară (PME) fiind îmbunătățită, reprezintă sursa de nutrienți și protejează comunitatea biofilmelor de desicare, radiații ultraviolete, celulele imune și antimicro- biene; (c) stadiul de maturizare (I, II). Primii colonişti facilitează sosirea altor celule prin furnizarea diverselor situsuri de adeziune, prin începerea construcţiei matricei care ţine unit biofilmul. Câteva specii nu sunt capa- bile să se ataşeze prin suprafeţele lor, dar adesea sunt capabile să se ancoreze la matrice sau direct la primii colonişti. În timpul colonizării aceste celule sunt capabile să comunice prin „molecule semnalˮ – quorum sensing sau folosind produşi ca lactonele homoserin acilate. În a doua faza de maturizare, biofilmul creşte prin com- binaţia dintre diviziunea celulară şi recrutarea de noi celule, procesul de formare a biofilmulului este stabil şi se poate modifică numai în formă şi dimensiune; d) etapa de eliberare și diseminare de celule din colonia biofilmului. Aceasta etapă permite biofilmelor să se răspândească şi să colonizeze noi suprafeţe, constituind o etapă esenţială a ciclului de viaţă al biofilmelor [16–18]. Formarea biofilmului nu este un factor clasic de virulență. Cu toate acestea, biofilmele conduc la creșterea patogenității, deoarece comunitatea celulelor devine prea mare pentru a fi fagocitată. Fungii din biofilme sunt mai rezistenți la stres oxidativ, iar PME afectează recunoașterea epitopilor fungici de suprafață de către celu- lele imune [17]. Biofilmele formate de fungi sunt subiectul unui șir de cercetări demonstrând implicarea celor mai importanți fungi din punct de vedere medical în formarea biofilmelor, precum Candida, Aspergillus, Cryptococcus, Trichos- poron, Coccidioides, Pneumocystis. Biofilmele fungice au implicații notabile din punct de vedere clinic și re- prezintă o formă specifică de creștere microbiană și veriga principală în dezvoltarea infecțiilor fungice [19–24]. Introducere p p ș ș g p p ț g [ Studiile realizate în ultimul deceniu au listat principalele caracteristici ale biofilmelor fungice importante pentru evoluția infecțiilor invazive: desprinderea agregatelor de biofilme, care pot genera infecții de flux sangvin sau embolii, schimbul intercelular de plasmide ce este implicat direct în transmiterea rezistenței antimicrobiene, microbii din biofilm sunt protejați de acțiunea antimicrobiană, biofilmele nu sunt afectate de clearance-ul sis- temului imun al gazdei [25]. Formarea biofilmelor de către tulpinile relevante clinic pe endoproteze, catetere, suprafața dispozitivelor medi- cale, ventilatoarelor mecanice, precum și măsurile de combatere a formării acestora au fost descrise într-un şir de cercetări din ultima perioadă. Alţi cercetători descriu consecinţele clinice semnificative ale infecţiei asociate cu biofilmele mature. Astfel, tratamentul antimicrobian de durată este adesea necesar pentru eradica- rea acestor infecţii (osteomielita, endocardita etc.); din păcate, chiar şi această strategie de multe ori eşuează, necesitând excizia chirurgicală a biofilmului contaminant [25–27]. Savanți din diferite țări cu puternic potențial de cercetare au semnalat necesitatea şi urgența studiilor privind elucidarea aprofundată a biofilmelor şi a celor de dezvoltare a strategiilor eficiente de prevenire a formării biofilmelor și/sau de tratamente pentru infecțiile cauzate. S T U D I A U N I V E R S I T A T I S M O L D A V I A E S T U D I A U N I V E R S I T A T I S M O L D A V I A E Revist= [tiin\ific= a Universit=\ii de Stat din Moldova, 2020, nr.1(131) nizațiilor internaționale în domeniu. Pentru elicidarea acestui subiect au fost revizuite şi sistematizate 98 de surse bibliografice, informaţiile publicate în ultimele decenii. În procesul de analiză au fost excluse 5 articole vechi care nu s-au găsit a fi sugestive. Astfel, în final au fost selectate 87 de publicații actuale și relevante, 6 articole mai vechi dar foarte demonstrative (în total 93 de lucrări stiintifice) privind structura, compoziția, me- canismele de formare, factorii ce influențează formarea și înlăturarea biofilmului. nizațiilor internaționale în domeniu. Pentru elicidarea acestui subiect au fost revizuite şi sistematizate 98 de surse bibliografice, informaţiile publicate în ultimele decenii. În procesul de analiză au fost excluse 5 articole vechi care nu s-au găsit a fi sugestive. Astfel, în final au fost selectate 87 de publicații actuale și relevante, 6 articole mai vechi dar foarte demonstrative (în total 93 de lucrări stiintifice) privind structura, compoziția, me- canismele de formare, factorii ce influențează formarea și înlăturarea biofilmului. Material şi metode Lucrarea analizează cele mai relevante publicații din literatura medicală din țară și de peste hotarele ei utilizând bazele de date PubMed, EMBASE, Scopus, HINARI, Google Academic și site-urile web ale orga- 101 Rezultate şi discuţii Istoricul biofilmelor și gradul de investigare a problemei la momentul actual Microorganismele au fost descrise sub formă planctonică și caracterizate pe baza proprietăților lor culturale, percepția clasică a microorganismelor unicelulare. Van Leewenhoek a fost primul savant care a descris feno- menul prin care aceste microorganisme aderă și se multiplică pe majoritatea suprafețelor, atât cele exterioare, cât și în organism, dând naștere biofilmului [2]. Termenul „biofilm” a fost introdus de Costerton în 1985. Autorul a definit biofilmul drept „o comunitate sesilă microbiană caracterizată prin celule care sunt atașate ireversibil de un substrat sau una de cealaltă, într- o matrice de substanță polimerică extracelulară și prezintă un fenotip modificat în raport cu rata de creștere și transcripția genelor” [28]. Primele biofilme au fost descrise în secolul al XIX-lea pe plăci dentare, apoi fibroza chistică a oferit modele de biofilme viabile, cu status sesil, fixat permanent sau temporar de substrat, constituind comunităţi celulare, comparative cu cele planctonice ce nu aderau la suprafaţă [11, 29]. Î p p p ţ [ , ] În alte studii se subliniază că biofilmele au devenit un domeniu de studiu începând cu sfârșitul anilor șaptezeci, când aceste structuri au fost aduse în atenția publicului de Bill Costerton și colaboratorii în 1978 [30]. Din acea perioadă până în prezent au apărut numeroase articole științifice, monografii ce abordează prob- lema privind formarea biofilmelor şi o parte din ele vor fi prezentate în prezenta lucrare. Interesul sporit al cercetătorilor faţă de biofilme se explică prin semnificaţia medicală, ecologică, biotehnologică şi teoretică a fenomenelor de aderenţă şi agregare microbiană. ţ ş g g Unele particularități ale biofilmelor formate de fungi din genul Candida g g Unele particularități ale biofilmelor formate de fungi din genul Candida Evidențele publicate privind biofilmelor fungice atestă o predominare a speciilor din genul Candida în etio- logia patologiei infecțioase de origine micotică. Speciile genului Candida, reprezențanț ai microflorei comen- sale, frecvent sunt implicate și în patologia infecțioasă. Dispozitive de tip: stent, șunt, proteze, implante sonde endotraheale, catetere etc., sunt frecvent colonizate de aceste tulpini și reprezintă surse pentru dezvoltarea de biofilme candidozice. Practic ultimul deceniu a cunoscut o creștere exponențială a infecțiilor de flux sangvin cauzate de Candida spp. (predominant Candida albicans), în paralel cu utilizarea pe scară tot mai largă a dis- pozitivelor mai sus amintite, astfel încât în acest moment fungii (și în special Candida albicans) reprezintă cea de-a treia cauză de infecții de cateter, soldate cu rată înaltă de mortalitate [12]. Î În colonizarea suprafețelor celulele fungice trebuie să adere la o suprafața hidrofobă a unui biomaterial, aspect mediat de forțele electrostatice, dar și adezine fungice, ce recunosc liganzi din suprafața de aderat (fibrinogen, fibronectină) etc. [53,56]. Biofilmele C. albicans sunt formate pe diverse suprafețe abiotice și biotice [31–33,43]. Alte specii de Candida, incluzând C. tropicalis, C. parapsiloză și C. glabrata, formează biofilme care conțin ECM, dar nu produc o hifă adevărată. Totodată, aceste specii pot coagrega bacterii, cu formarea de biofilme polimicrobiene: bacte- riene și fungice. Aderarea celulelor la un substrat este urmată de diviziune celulară, proliferare și dezvoltarea biofilmului, structură tridimensională complexă, cu aranjament spațial optim pentru transportul nutrienților și eliminarea deșeurilor [35]. Studiile analizate demonstrează implicarea biofilmelor formate de microorganismele din genul Candida la bolnavi cu dispozitive implantabile (proteze valvulare, endovasculare, articulare, dar, mai ales, catetere ve- noase centrale). Autorii subliniază că pătrunderea acestora în circulația sistemică constituie adesea puncte de plecare pentru infecții micotice invasive [12, 33, 43]. Cercetările evidențiază în dezvoltarea biofilmelor de Candida spp. unele particularități, aderarea celulelor fungice fiind urmată la 3-6 ore de formarea structurilor tubulare. După o incubație de 24-48 ore biofilmele ma- turate de Candida albicans dispun de o rețea densă de celule fungice, hife și pseudohife și matrice polimerică extracelulară. Dat fiind faptul că filamentarea nu a fost descrisă la formele planctonice, este posibil ca acest aspect să fie favorizat de formarea biofilmului. Microscopia electronică a permis vizualizarea de canale hi- drice ramificate în biofilm, cu dimensiuni de 25-450 µm [36]. 102 Seria “{tiin\e reale [i ale naturii” {tiin\e Biologice ISSN 1814-3237 Capacitatea de a se transforma reversibil din celule fungice în filamente a celulelor de C. g g Unele particularități ale biofilmelor formate de fungi din genul Candida albicans (conversia morfogenetică) are rol decisiv în dezvoltarea biofilmului. Autorii studiilor axate inclusiv pe conversia morfo- genetică denotă că hifele constituie elemente esențiale pentru integritatea structurală, arhitectura multistratificată ce caracterizează biofilme maturate [37]. Ramage și col. au demonstrat că substratul molecular al filamentării celulelor de Candida și dezvoltării bio- filmelor mature, înalt structurate, este asigurat de prezența proteinei Efg1 [38]. Majoritatea studiilor analizate subliniază rolul decesiv al comunicării intercelulare (quorum sensing-QS) în procesul de formare a biofilmului. QS controlat de proteina de transducție Chk1p asigură monitorizarea multiplicării celulare pentru a evita suprapopularea, dar și competiția pentru nutrienți, cu implicații serioase pentru procesul infecțios, în special în diseminarea infecției și apariția de emboli septici la distanță. Un exemplu interesant de comunicare intercelulară în biofilm este dat de interacțiunea Candida albicans și Pseudomonas aeruginosa. Celulele de Pseudomonas formează un biofilm extrem de dens pe filamentele de Candida și distruge fungii, dar bacteriile nu distrug formele celulare de Candida. Totodată, celulele de Candida spp. pot stopa filamentarea ca răspuns la expunerea contactului cu molecule de comunicare cu Pseudomonas de tip 3-oxo- C12homoserin lactonă. Studiile demonstrează că morfogeneza Candidei albicans se află sub controlul mediului înconjurător al biofilmului [39–41]. j [ ] Arhitectura biofilmului fungic pathogen Dezvoltarea arhitecturii biofilmelor este în mare măsură legată de producerea matricei polimerice extracelu- lare (MPE) de către microorganisme. MPE reține apa și nutrienții obținuți din materialele matricei hidrolizate de enzimele produse de microorganisme [12,42]. Prin urmare, matricea include toate elementele biofilmului şi este compusă în principal din apă (până la 97%), polimeri polizaharidici secretaţi de microorganisme și produse de degradare a substanțelor din mediul extern și alte componente, cum ar fi ADN, ARN și lipide. Spre deosebire de culturile clasice de microorga- nisme din mediile lichide agitate, biofilmul nu este un mediu omogen, deoarece prezintă zone cu conţinut va- riabil de oxigen şi nutrienţi, pH diferit [42–44]. Regiunile din centrul agregatelor bacteriene sunt în general anaerobe şi sărace în nutrimente, în timp ce cele situate în vecinătatea canalelor sau la interfaţa dintre biofilm şi lichid sunt mai bine oxigenate şi mai bo- gate în nutrienţi [45]. Biofilmul este acoperit în întregime de MPE, astfel protejează și oferă o structură ideală pentru coeziunea și adeziunea celulelor [42]. Cea mai relevantă funcție din punct de vedere medical a matricei extracelulare este capacitatea sa de a oferi o barieră fizică între celulele de biofilm și sistemul imunitar și adesea medicamentele utilizate pentru tratament [46]. MPE este autoprodusă și poate conține proteine, polizaharide, lipide, acizi nucleici și alte molecule care pot interacționa între ele și cu suprafața celulei pentru a forma o rețea rigidă de protecție [47]. Compoziția MPE variază în funcție de specii și chiar de condiții de creștere; cu toate acestea, pentru multe biofilme compoziția MPE rămâne necunoscută [42,48]. Funcțional, MPE poate servi drept barieră protectoare împotriva agenților antimicrobieni, chimici și biologici, inclusiv către preparate antimicotice prescrise [48,49]. Biofilmele, fiind populații complexe de celule asociate suprafeței înglobate într-un MPE, posedă fenotipuri distincte în comparație cu omologii lor celulari planctonici. Elementele nutritive, moleculele sensibile la cvorum și contactul cu suprafața sunt factori favorizanți. Biofilmele de C. albicans sunt constituite în principal din celule sub formă de levuri și hife, ambele fiind necesare pentru formarea biofilmului [19]. MPE se acumulează pe măsură ce biofilmul se maturizează și contribuie la coeziune [50]. Biofilmele de Aspergillus se pot forma atât pe suprafețele abiotice, cât și pe cele biotice. Celulele inițiale colonizatoare care aderă la substrat sunt conidii. Micelia (forma hifală) se dezvoltă pe măsură ce biofilmul se maturizează [51]. MPE care încheagă biofilmul a fost observat in vitro și în vivo. Revist= [tiin\ific= a Universit=\ii de Stat din Moldova, 2020, nr.1(131) C. neoformans formează biofilme constând din celule de drojdie pe multe substraturi abiotice, iar poliza- haridul capsular sintetizat formează ECM. Cu toate că C. neoformans formează hifa în cursul grupării, până în prezent nu s-au observat hife în biofilmele de C. neoformans [21]. Î p f În mod similar, speciile Pneumocystis nu produc structuri hifale ca parte a biofilmelor lor. Astfel, formarea hifală nu este o caracteristică uniformă a biofilmelor fungice [24]. g Comunicarea intercelulară prin semnale (quorum sensing - QS) Î Comunicarea intercelulară prin semnale (quorum sensing - QS) Î În biofilme QS este gândit să joace un rol în producţia de biofilme sănătoase şi pe deplin dezvoltate. Aceste complexe microbiene definesc structuri multistratificate arhitectural formând comunităţi bacteriene relativ stabile ce trăiesc în sesile într-un mediu protejat [28, 56–59]. Comunicarea intercelulară, este legată de mecanismul prin care microorganismele comunică și își coordo- nează comportamentul prin secreția de molecule de semnalizare [60,61]. Sistemele QS par să fie implicate în toate etapele de formare a biofilmelor. Ele reglează densitatea populaţiei şi activitatea metabolică în biofilmul matur pentru a se potrivi cu cerinţele nutriţionale şi resursele disponibile. Bacteriile care locuiesc în biofilme au programe semnificativ diferite de transcripţie faţă de bacteriile plancto- nice vii libere ale aceleiaşi tulpini. Dovezi recente privind Streptococcus pneumoniae indică faptul că orga- nismele existente într-o stare sesilă în biofilm sunt mai în măsură să stabilească infecţii localizate (de exemplu, în ţesutul pulmonar) decât microorganismele izogenice într-o stare planctonică fiziologic [62–65]. QS joacă rol în mai multe mecanisme, inclusiv dezvoltarea biofilmului, morfogeneza, limitarea populației celulare și, în special, pentru diseminarea procesului infecțios [61,63]. Detectarea QS este de o importanță funda- mentală și este datorată rolului specific ce îl determină în fiziologia biofilmului. Celulele persistente reprezintă o mică subpopulație de celule care intră spontan într-o stare latentă ce nu divizează. Atunci când o populație este tratată cu antimicrobiane, celulele normale pier, în timp ce cele persistente supraviețuiesc. În cazul în care terapia este întreruptă, celule persistente pot reface biofilmele, inducând recurența infecțiilor [66]. Mecanismele moleculare care promovează rezistența antifungică în biofilmele fungice nu sunt complet elu- cidate. Unele studii au arătat că pompele de eflux contribuie la dezvoltarea rezistenței față de azoli numai în faza inițială a formării biofilmului. În plus, conținutul de sterol în membrană contribuie la rezistența anti-azoli, ce apare în timpul fazelor intermediare și mature [67]. Revist= [tiin\ific= a Universit=\ii de Stat din Moldova, 2020, nr.1(131) Conform Soto și col., reglarea pompelor de eflux medicamentos determină, de asemenea, rezistența la anti- microbiene la majoritatea microorganisme ce formează biofilm [68]. Aceste pompe sunt împărțite în două grupuri: primul este legat de transportoarele- casetă ATP-ligande co- dificate de genele CDR, în timp ce al doilea este compus din facilitatorul principal codificat de genele MDR [49]. Activarea pompelor de eflux are loc prin „expulzarea” preparatelor antifungice după contactul cu biofilmul. Totodată, crește expresia genelor CDR1 și MDR1, care a fost corelată cu rezistența fungilor la azoli. Unele studii privind rezistența la biofilm demonstrează expresia înaltă a genelor pompei de eflux în primele ore de formare a biofilmului [49]. Semnificația biofilmelor în dezvoltarea rezistenței antifungice j [ ] Arhitectura biofilmului fungic pathogen Organizarea hifală este diferită în cele două forme ale infecției cu biofilm de A fumigatus: infecțiile cu aspergillom prezintă o minge de hife interconectate; MPE se acumulează pe măsură ce biofilmul se maturizează și contribuie la coeziune [50]. Biofilmele de Aspergillus se pot forma atât pe suprafețele abiotice, cât și pe cele biotice. Celulele inițiale colonizatoare care aderă la substrat sunt conidii. Micelia (forma hifală) se dezvoltă pe măsură ce biofilmul se maturizează [51]. MPE care încheagă biofilmul a fost observat in vitro și în vivo. Organizarea hifală este diferită în cele două forme ale infecției cu biofilm de A. fumigatus: infecțiile cu aspergillom prezintă o minge de hife interconectate; infecțiile cu aspergiloză prezintă hife separate individuale [42,51,52]. Hifele C. albicans și A. fumigatus pot forma pori sau canale pe suprafețe biotice [43,75]. Patogenul fungic emergent T. asahii formează biofilme compuse din levuri și celule hifale încorporate în matrice, la fel ca cele ale Coccidioides immitis [22,53–55]. 103 S T U D I A U N I V E R S I T A T I S M O L D A V I A E Semnificația biofilmelor în dezvoltarea rezistenței antifungice Majoritatea cercetărilor descriu rezistența antifungică a biofilmelor ca un fenomen complex cu multe aspecte neelucidate. Microorganismele din structura biofilmelor își încetinesc rata de multiplicare, ceea ce face mai greu de distrus de antimicrobiene. Prezența microorganismelor facilitează dezvoltarea matricei polimerice care protejează microbii din fluxul sangvin de actiunea preparatelor antifungice. În același timp, se atestă modificări de com- portament microbian tipice germenilor din biofilm și faptul că majoritatea acestora suferă de modificări la ni- velul genelor (de tip up- sau down-regulation) caracteristice fiecărei clase în parte, evidențiază că biofilmele reprezintă o modalitate de creștere a rezistenței antimicrobiene și se conturează ca o problemă de sănătate pub- lică, mai ales pentru bolnavul critic și pentru cel cu imunodepresie severă de diverse cauze [69]. Î În biofilm, este facilitat transferul de ADN extracromozomial (plasmide) între celule, element care de asemenea favorizează apariția și răspândirea rezistenței antimicrobiene. Agregatele de biofilm se pot desprinde și celu- lele microbiene își pot relua rapid proprietățile planctonice sau de aderare la alte suprafețe. În ambele situații, aceste structuri posedă potențial de a transfera la distanță și genele de rezistență antimicrobiană. Astfel, după cum a fost evidențiat și de alți savanți, microorganismele din structura biofilmului sunt o populație cu metabo- lism diferit de al celor în stare planctonică și pot declanșa infecții grave [70]. 104 Seria “{tiin\e reale [i ale naturii” {tiin\e Biologice ISSN 1814-3237 Totodată, aglomerările de celule ce formează biofilme sunt mult mai rezistente la preparatele antifungice decât celulele planctonice. Factorii care contribuie la acest fenomen includ complexitatea structurală a biofil- mului, prezența matricei extracelulare (ECM), heterogenitatea metabolică intrinsecă a biofilmelor și reglarea asociată genelor generatoare de biofilm cu efect asupra pompei de eflux. Nivelul de rezistență variază în de- pendență de preparatul antifungic și specia de micete [70–72]. Evidențele în acest domeniu subliniază că modificările sau supraexpresia moleculelor țintă, extruzarea activă prin pompe de eflux, difuzia limitată, rezistența și comunicarea intercelulară (quorum sensing) și matricea polimerică extracelulară sunt mecanisme caracteristice fungilor pentru combaterea efectelor tratamentului antimicotic [72, 73]. MPE este produsă de celulele aderente, constituind o barieră în difuziunea antifungicelor. Studiile denotă că, în unele cazuri, MPE poate contribui la rezistența antifungică prin legarea la antifungice, împiedicând astfel accesul la suprafața țintei dorite sau la celulele fungice [74]. Actualmente o provocare aparte reprezintă dovezile științifice insuficiente privind rezistența la antifungice a acestor biofilme. Semnificația biofilmelor în dezvoltarea rezistenței antifungice Majoritatea standardelor internaționale existente permit testarea formelor planctonice, dar nu și estimarea sensibilității antifungice pentru celulele din biofilme. Acest aspect ar putea fi o explicație pentru discrepanța dintre investigațiile de laborator și evoluția clinică a acestor infecții [75]. Actualmente există puține studii ce descriu astfel de metodologii, iar în unul dintre ele se propune folosirea microplăcilor pe care se for- mează biofilme, ce sunt expuse ulterior la diverse antifungice. Biofilmele de Candida spp. sunt descrise de un șir de autori ca una dintre cauzele evoluției rezistenței antifungice. Este îmbucurător faptul că antifungice noi, cum ar fi echinocandinele și forma liposomală a Amfotericinei B, au dovedit acțiunea fungicidă pentru microorganismele din biofilme [76]. Celulele planctonice depind de modificări genetice ireversibile pentru a menține un fenotip rezistent, în timp ce biofilmele persistă din cauza prezenței lor fizice și a densității populației, oferind un fenotip rezistent aproape indus, indiferent de modificările genetice definite [77,78]. Mai mulți factori ai mediului, inclusiv pH-ul, temperatura, disponibilitatea oxigenului și alții, modifică arhi- tectura biofilmului și susceptibilitatea antifungică [79]. Rezistența intrinsecă a biofilmelor de Candida presupune diferite mecanisme: densitatea celulară mare a biofilmului, reducerea ratei multiplicării și limitarea nutrienților, activitatea matrice polimerice extracelulare, expresia genelor responsabile de rezistență (în special a celor care codifică pompele de eflux) etc. [80]. Chandra și col. au demonstrat că intensitatea ratei metabolice a biofilmului este corelată cu creșterea rezis- tenței antifungice. Reducerea semnificativă a cantității de ergosterol din biofilme în fazele intermediară și de maturitate, face ca majoritatea antifungicelor care au mecanism fungicid (interferența cu metabolismul stero- lilor) să reducă eficiența acestora [81]. Candida parapsilosis este relativ rezistentă la fluconazol, amfotericină B, nistatină, voriconazol și altele. Biofilmele Aspergillus fumigatus sunt relativ rezistente la itraconazol și, într-o oarecare măsură, la caspofungină. Biofilmele criptococice nu sunt afectate de fluconazol și voriconazol, iar biofilmele de Trichosporon asahii prezintă o rezistență crescută la amfotericină B, caspofungin, voriconazol și fluconazol. Terapiile cu azoli și amfotericină B sunt ineficiente împotriva biofilmelor de Pneumocystis carinii. Mecanismele de rezistență asociate biofilmului au fost caracterizate pentru C. albicans și A. fumigatus și includ legarea medicamentelor prin MPE și producerea de celule persistente. Aceste mecanisme se pot referi și la alți fungi [20,82–84]. Antifungicele nu reușesc să acționeze eficient, deoarece există un gradient de mediu (heterogenitate) în cadrul biofilmelor. Revist= [tiin\ific= a Universit=\ii de Stat din Moldova, 2020, nr.1(131) [tiin\ific= a Universit=\ii de Stat din Moldova, 2020, nr.1(131) Noi strategii alternative de control al biofilmelor Majoritatea studiilor analizate propun noi strategii alternative de control al biofilmelor microbiene, precum sunt compușii biologici cu proprietăți antibacteriene și antibiofilme. Există foarte puţine preparate antimicotice ca opţiuni împotriva formelor de fungi încadrate în biofilm; printre ele se enumeră amfotericina B și echino- candinele. Prin urmare, este nevoie de mai mulți agenți, care pot inhiba aderența la biofilm sau pot elimina sau perturba biofilmul deja format [87]. Civilizaţiile antice au lăsat informaţii scrise legate de utilizarea produselor naturale în terapia maladiilor infecțioase. Cel mai vechi document scris datează de acum 4000 de ani, acesta conţine informaţii ce prevăd remedierea diverselor boli. Totodată, cercetarea metaboliţilor biologici activi secundari pentru aplicaţii folo- sitoare este departe de a fi considerată nouă [88, 89, 90]. La moment au fost identificate mai multe ținte noi sub formă de componente ale MPE. Multe extracte ve- getale, nanoparticule de argint, oxid nitric, chitosan etc. au fost încercate pentru a preveni formarea biofilmului pe suprafețele cateterelor și dispozitivelor intravasculare [91]. Avantajul produselor naturale este dezvoltarea şi perfecţionarea continuă, de-a lungul milioanelor de ani de presiune evolutivă, pentru a ajunge puternice din punct de vedere biologic. Substanțele obținute natural, comparativ cu cele artificiale, posedă potențial de biodegradare mult mai înalt şi rapid, fiind acceptate pe piață mult mai usor din punct de vedere ecologic [88]. Produsele naturale sunt remarcabile prin diversitatea structurii şi activităţii biologice, în contrast cu substan- ţele produse de industria farmaceutică, ce utilizează metode sintetice, care rareori prezintă o activitate puternică și diversificată biologic [92]. ș g Aceste ipoteze se bazează pe diversitatea şi capacitatea microorganismelor de a se adapta și, prin urmare, acestea reuşesc să degradeze majoritatea substanţelor naturale. Istoric de mii de ani, produsele naturale au ju- cat un rol foarte important în fortificarea sănătății și prevenirea maladiilor infecțioase [93]. Î Aceste ipoteze se bazează pe diversitatea şi capacitatea microorganismelor de a se adapta și, prin urmare, acestea reuşesc să degradeze majoritatea substanţelor naturale. Istoric de mii de ani, produsele naturale au ju- cat un rol foarte important în fortificarea sănătății și prevenirea maladiilor infecțioase [93]. Î În pofida faptului că până la moment există multe studii ce țin de activitatea antimicrobiană a extractelor vegetale asupra microorganismelor rezistente, totodată relativ puţine din ele s-au dovedit a fi suficient de active și inofensive pentru organismul uman. S T U D I A U N I V E R S I T A T I S M O L D A V I A E S T U D I A U N I V E R S I T A T I S M O L D A V I A E Concluzii Concluzii 1. Biofilmele sunt omniprezente, aproape fiecare specie de microorganisme are mecanismele prin care acestea pot adera la suprafeţe vii sau non-vii; ele pot fi răspândite pretutindeni în natură. 1. Biofilmele sunt omniprezente, aproape fiecare specie de microorganisme are mecanismele prin care acestea pot adera la suprafeţe vii sau non-vii; ele pot fi răspândite pretutindeni în natură. p p p p p 2. Majoritatea biofilmelor fungice sunt responsabile de infecții foarte rezistente la antimicrobiene, constituind o preocupare serioasă a serviciilor de sănătate publică, prin creșterea duratei de spitalizare, ratei de morta- litate și a impactului asupra economiei naționale și globale. 2. Majoritatea biofilmelor fungice sunt responsabile de infecții foarte rezistente la antimicrobiene, constituind o preocupare serioasă a serviciilor de sănătate publică, prin creșterea duratei de spitalizare, ratei de morta- litate și a impactului asupra economiei naționale și globale. 3. Actualmente, pe plan mondial sunt disponibile noi strategii alternative de control al biofilmelor, cum ar fi: substanțe biologic active de origine vegetală, enzime și bacteriofagi. Aceste studii sunt la etapa inițială, de cercetare in vitro, și necesită studii clinice aprofundate. transmitem recomandări cercetătorilor privind necesitatea studiilor ce țin de identificarea soluțiil pentru prevenirea și controlul infecțiilor cauzate de biofilm. 4. În final transmitem recomandări cercetătorilor privind necesitatea studiilor ce țin de identificarea soluțiilor eficiente pentru prevenirea și controlul infecțiilor cauzate de biofilm. Noi strategii alternative de control al biofilmelor În pofida faptului că până la moment există multe studii ce țin de activitatea antimicrobiană a extractelor vegetale asupra microorganismelor rezistente, totodată relativ puţine din ele s-au dovedit a fi suficient de active și inofensive pentru organismul uman. ș p g Autorii acestui rewiu subliniază necesitatea studiilor suplimentare privind metodele alternative de obținere a preparatelor cu acțiune antifungică, naturale, ecologic standardizate, inofensive. ș p g Autorii acestui rewiu subliniază necesitatea studiilor suplimentare privind metodele alternative de obținere a preparatelor cu acțiune antifungică, naturale, ecologic standardizate, inofensive. Semnificația biofilmelor în dezvoltarea rezistenței antifungice Aceste biofilme fiind după structură asemănătoare cu fungii duc la formarea gradientului de concentrație sub formă de gradient de oxigen chimic, pH sau gradient de nutrienți. Diferite concentrații de antimicrobiene ating diverse celule individuale în diferite straturi de biofilme. Această concentrație suboptimă acționează ca stimul pentru formarea suplimentară a biofilmului și, de asemenea, duce la dezvoltarea rezistenței la antimicrobiene [85]. Alte mecanisme implicate în rezistența la antimicrobiene sunt: densitatea celulară crescută, modificarea țintelor medicamentoase și reglarea pompelor de eflux pe măsură ce biofilmele se maturizează. MPE se ma- nifestă ca o barieră fizică și împiedică pătrunderea preparatelor antifungice în interiorul biofilmului. Există o concentrație crescută de substanțe, cum ar fi beta-glucanii și mananele, în MPE, care acționează ca „bureți medicamentoși” și sechestrează azolii, pirimidinele sau polienele. MPE conține ADN extracelular. Dacă se adaugă AND-aze la modelele de biofilm, CMI-ul antifungicelor scade semnificativ [73,86]. 105 gy p 6. Harvey, R.J., Lund, V.J. Biofilms and chronic rhinosinusitis: systematic review of evidence, current concepts and directions for research. În: Rhinology, 2007, no.45, p.3-13. 2. McCARTY, S., WOODS, E., PERCIVAL, S.L. Biofilms: from Concept to Reality. Elsevier Inc., 2014. 3. COSTERTON, J.W., WILSON, M. Introducing biofilms. Biofilms. In: Cambridge University Press, UK, 2004, p.1-4. ISBN 0-521-66275-3. ISBN 0 521 66275 3. 4. WEST, S.A., DIGGLE, S.P., BUCKLING, A., GARDNER, A., GRIFFIN, A.S. The social lives of microbes. In: The Annual Review of Ecology, Evolution and Systematics, 2007, no.38, p.53-77. eISSN 1545-2069 5. COSTERTON, J.W., LEWANDOWSKI, Z., CALDWELL, D.E., et al. Microbial films. In: Annual Reviews in Micro- biology, 1995, no.49, p.711-745. eISSN 1545-3251 Referințe: 1. COSTERTON, J.W., CHENG, K.J., GESSEY, G.G., LADD, T.I., NICKEL, J.C., DASGUPTA, M., MARRIE, T.J. Bacterial biofilms in nature and disease. In: Annual Reviews in Microbiology. 1987, no.41, p.435-464. eISSN 1545- 3251 1. COSTERTON, J.W., CHENG, K.J., GESSEY, G.G., LADD, T.I., NICKEL, J.C., DASGUPTA, M., MARRIE, T.J. Bacterial biofilms in nature and disease. In: Annual Reviews in Microbiology. 1987, no.41, p.435-464. eISSN 1545- 3251 , , , , , f f p y , 3. COSTERTON, J.W., WILSON, M. Introducing biofilms. Biofilms. In: Cambridge University Press, UK, 2004, p.1-4. ISBN 0-521-66275-3. 4. WEST, S.A., DIGGLE, S.P., BUCKLING, A., GARDNER, A., GRIFFIN, A.S. The social lives of microbes. In: The Annual Review of Ecology, Evolution and Systematics, 2007, no.38, p.53-77. eISSN 1545-2069 5. COSTERTON, J.W., LEWANDOWSKI, Z., CALDWELL, D.E., et al. Microbial films. In: Annual Reviews in Micro- biology, 1995, no.49, p.711-745. eISSN 1545-3251 106 Seria “{tiin\e reale [i ale naturii” ISSN 1814-3237 {tiin\e Biologice 7. Hall Stoodley, L., Stoodley, P. Evolving concepts in biofilm infections. În: Cell Microbiol Infect Immun, 2009, no.73, p.4653-4667. M.W., MARQUES, L.L.R., HOWARD, R.J., OLSON, M.E. Can filamentous fungi form biofilms? In: crobiology, 2009, no.17, p.475-480. ISSN 1878-4380 (online) 9. KECK, T., LEIACKER, R., RIECHELMANN, H. et al. Temperature profile in the nasal cavity. In: Laryngoscope, 2000, no.110, p.651-654. Online ISSN: 1531-4995 , , p 10. BRANDA, S.S., VIK, A., FRIEDMAN, L., KOLTER, R. Biofilms: the matrix revisited. In: Trends in Microbiology, 2005, no.13, p.20-26. ISSN 1878-4380 (online) 11. COSTERTON, J.W., STEWART, P.S. and GREENBERG, E.P. Bacterial biofilms: a common cause of persistent infections. In: Science, 1999, vol.284, no5418, p.1318-1322. 12. JAMAL, M., AHMAD, W., ANDLEEB, S., JALIL, F., IMRAN, M., NAWAZ, M.A., et al. Bacterial biofilm and associated infections. In: Journal of the Chinese Medical Association, 2018, no.81, p.7-11. . WOLCOTT, R.D., EHRLICH, G.D. Biofilms and chronic infections. In: Journal of the American Medical 2008, no.299, p.2682-2684. ISSN 0098-7484 (print), 1538-3598 (web) p p . LEWIS, K. Persister cells. In: Annual Reviews in Microbiology, 2010, nr.64, p.357-72. eISSN 1545-325 15. JABRA-RIZK, M.A., FALKLER, W.A., MEILLER, T.F. Fungal biofilms and drug resistance. In: Emerging Infectious Diseasis, 2004, no.10:14-9. ISSN 1080-6059 . KARATAN, E., WATNICK, P. Signals, regulatory networks, and materials that build and break bacterial Microbiology and Molecular Biology Reviews, 2009, no.73(2):310-47. Print ISSN 1092-2172, online ISSN gy gy 17. RAJENDRAN, R., MAY, A., SHERRY, L., KEAN, R., WILLIAMS, C., JONES, B.L. et al. Referințe: Integrating Candida albicans metabolism with biofilm heterogeneity by transcriptome mapping. In: Scientific Reports, 2016, no.6, p.354,356. ISSN: 2045-2322 (online) ( ) . FLEMMING, H.C., NEU, T.R., WOZNIAK, D.J. The EPS matrix: The „house of biofilm cells”. In: Journa logy, 2007, no.189:7945-7947. Print ISSN 0021-9193, online ISSN 1098-5530 gy 19. FINKEL, J.S., MITCHELL, A.P. Genetic control of Candida albicans biofilm development. In: Nature Reviews Micro- biology, 2011, no.9, p.109-118. ISSN 1740-1534 (online) gy, , , p ( ) 20. BEAUVAIS, A., MULLER, F.M. Biofilm formation in Aspergillus fumigatus. In: Latge J.P., Steinbach W.J., editors. Aspergillus fumigatus and aspergillosis. Washington (D.C.): ASM Press. 2009, p.149-157. 21. MARTINEZ, L.R., CASADEVALL, A. Cryptococcus neoformans biofilm formation depends on surface support and carbon source and reduces fungal cell susceptibility to heat, cold, and UV light. In: Applied Environmental Micro- biology, 2007, no.73, p.4592-4601. online ISSN 1098-5336 gy p 22. Di BONAVENTURA, G., POMPILIO, A., PICCIANI, C., IEZZI, M., D’ANTONIO, D. et al. Biofilm formation by the emerging fungal pathogen Trichosporon asahii: development, architecture, and antifungal resistance. In: Antimicrobial Agents and Chemotherapy, 2006, no.50, p.3269-3276. g py p 23. DAVIS, L.E., COOK, G., COSTERTON, J.W. Biofilm on ventriculo-peritoneal shunt tubing as a cause of treatment failure in coccidioidal meningitis. In: Emergyng Infectious Diseases, 2002, no.8, p.376-379. ISSN 1080-6059 24. CUSHION, M.T., COLLINS, M.S., LINKE, M.J. Biofilm formation by Pneumocystis spp. In: Eukaryotic Cell., 2009, nr.8: 197-206. Print ISSN 1535-9778, online ISSN 1535-9786 25. MILLER, M.B., BASSLER, B.L. Quorum sensing in bacteria. In: Annual Reviews in Microbiology, 2001, no.55, p.164-199. eISSN 1545-3251 p 26. Hall-Stoodley. Bacterial biofilms: from the natural environment to infectious diseases. In: Nature Reviews Microbiology, 2004, no.2(2), p.95-108. ISSN 1740-1534 (online) 27. KONG, K.F., VUONG, C., OTTO, M. Staphylococcus quorum sensing in biofilm formation and infec tional Journal of Medical Microbiology, 2006, no.296, p.133-139. ISSN 1438-4221 27. KONG, K.F., VUONG, C., OTTO, M. Staphylococcus quorum sensing in biofilm formation and infection. In: Interna- tional Journal of Medical Microbiology, 2006, no.296, p.133-139. ISSN 1438-4221 28. DONLAN, R.M., COSTERTON, J.W. Biofilms: Survival mechanisms of clinically relevant microorganisms. In: Clinical Mi bi l R i 2002 15 167 193 P i t ISSN 0893 8512 li ISSN 1098 6618 tional Journal of Medical Microbiology, 2006, no.296, p.133-139. ISSN 1438-4221 28. DONLAN, R.M., COSTERTON, J.W. Biofilms: Survival mechanisms of clinically relevant microorganisms. In: Clinical Microbiology Reviews 2002 no15 p 167-193 Print ISSN 0893-8512 online ISSN 1098-6618 28. Referințe: Microbiol., 2009, no35(4), p.340-355. doi: 10.3109/10408410903241436 39. de BARROS, P.P., ROSSONI, R.D., de SOUZA, C.M., et al. Candida Biofilms: An Update on Developmental Mechanisms and Therapeutic Challenges. In: Mycopathologia, 2020, no185, p.415-424. [Accesat: 20.03.2020]. Disponibil: https://doi.org/10.1007/s11046-020-00445-w Print ISSN 0301-486X, electronic ISSN 1573-0832 p p g , 40. PADDER, S.A., PRASAD, R. and SHAH, A.H. Quorum sensing: A less known mode of communication among fungi. In: Microbiological Research., 2018, no.210, p.51-58. DOI: 10.1016/j.micres.2018.03.007. ISSN 0944-5013 , , , , Q g g fungi. In: Microbiological Research., 2018, no.210, p.51-58. DOI: 10.1016/j.micres.2018.03.007. ISSN 0944-5013 41. RUTHERFORD, S.T., BASSLER, B.L. Bacterial quorum sensing: its role in virulence and possibilities for its control. In: Cold Spring Harbor Perspectives in Medicine, 2012, no2(11), p.a012427. Published 2012 Nov 1. doi:10.1101/cshperspect.a 012427. Online ISSN 2157-1422 41. RUTHERFORD, S.T., BASSLER, B.L. Bacterial quorum sensing: its role in virulence and possibilities for its control. In: Cold Spring Harbor Perspectives in Medicine, 2012, no2(11), p.a012427. Published 2012 Nov 1. doi:10.1101/cshperspect.a 012427. Online ISSN 2157-1422 p p 42. FLEMMING, H.C., WINGENDER, J., SZEWZYK, U., STEINBERG, P., RICE, S.A., KJELLEBERG, S. Biofilms: an emergent form of bacterial life. In: Nature Reviews Microbiology, 2016, no14, p.563-575. ISSN 1740-1534 (online) 43. SIMOES, M., SIMOES, L.C., VIEIRA, M.J. A review of current and emergent biofilm control strategies. In: LWT – Food Science and Technology. (Lebensmittel-Wissenschaft-Technol.), 2010, no.43, p.573-583. 44. STOODLEY, P., DEBEER, D., LEWANDOWSKI, Z. Liquid Flow in Biofilm Systems. In: Applied Environmental Microbiology, 1994, vol.60, p.2711-27. Print ISSN 0099-2240, online ISSN 1098-5336 45. LAWRENCE, Jr., KORBER, D.R., HOYLE, B.D., COSTERTON, J.W., CALD-WELL, D.E. Optical sectioning ofmicrobial biofilms. In: Journal of Bacteriology, 1991, vol.173, p.6558-6567. Print ISSN 0021-9193, online ISSN 1098-5530 46. MITCHELL, K.F., ZARNOWSKI, R., ANDES, D.R. The extracellular matrix of fungal biofilms. In: Advances in Experimental Medicine and Biology, 2016, no 931, p.21-35. ISSN 0065-2598 47. JENNINGS, L.K., STOREK, K.M., LEDVINA, H.E. et al. Pel is a cationic exopolysaccharide that cross-links extra- cellular DNA in the Pseudomonas aeruginosa biofilm matrix. In: Procedeengs of the National Academy of Science of the United States of America, 2015, no.112, p.11353-11358. Online ISSN 1091-6490 48. REICHHARDT, C., STEVENS, D.A., CEGELSKI, L. Fungal biofilm composition and opportunities in drug discovery. In: Future Medicinal Chemistry, 2016, no.8, p.1455-1468. ISSN (print): 1756-8919, ISSN (online): 1756-8927 49. MATHE, L., van DIJCK, P. Recent insights into Candida albicans biofilm resistance mechanisms. In: Current Genetics, 2013, no.59, p.251-264. ISSN: 0172-8083 50. Referințe: DONLAN, R.M., COSTERTON, J.W. Biofilms: Survival mechanisms of clinically relevant microorgani Microbiology Reviews, 2002, no15, p.167-193. Print ISSN 0893-8512, online ISSN 1098-6618 gy p 29. ALLEGRUCCI, M., SAUER, K. Characterization of colony morphology variants isolated from S. Pneumoniae biofilms. In: Journal of Bacteriology, 2007, no189(5), p.2030-2038. Print ISSN 0021-9193, online ISSN 1098-5530 f gy p 30. COSTERTON, J.W., GEESEY, G.G., CHENG, K.J. How bacteria stick. In: Scientific American, 1978, no238, p.86-95. ISSN 0036-8733 31. ANDES, D, NETT, J, OSCHEL, P, ALBRECHT, R, MARCHILLO, K, et al. Development and characterization of an in vivo central venous catheter Candida albicans biofilm model. In: Infect Immun, 2004, no72, p.6023-6031. 32. MM, Harriott, EA, Lilly, TE, Rodriguez, FIDEL, PL Jr, NOVERR, MC. Candida albicans forms vaginal mucosa. In: Microbiology, 2010, no156, p.3635-3644. 32. MM, Harriott, EA, Lilly, TE, Rodriguez, FIDEL, PL Jr, NOVERR, MC. Candida albicans forms biofilms on the vaginal mucosa. In: Microbiology, 2010, no156, p.3635-3644. 33 KAMAI Y KUBOTA M HOSOKAWA T FUKUOKA T FILLER S G N d l f h l didi i . KAMAI, Y., KUBOTA, M., HOSOKAWA, T., FUKUOKA, T., FILLER S.G. New model of oropharyngea in mice. In: Antimicrob Agents Chemother, 2001, no45, p.3195-3197. g p 34. DONGARI-BAGTZOGLOU, A., KASHLEVA, H., DWIVEDI, P., DIAZ, P., VASILAKOS, J. Characterization of mucosal. In: Candida albicans biofilms, 2009. PLoS ONE 4: e7967 107 S T U D I A U N I V E R S I T A T I S M O L D A V I A E Revist= [tiin\ific= a Universit=\ii de Stat din Moldova, 2020, nr.1(131) 35. SILVA, S., NEGRI, M., HENRIQUES, M., OLIVEIRA, R., WILLIAMS, D.W. et al. Adherence and biofilm formation of non-Candida albicans Candida species. In: Trends Microbiol, 2011, no.19, p.241-247. 35. SILVA, S., NEGRI, M., HENRIQUES, M., OLIVEIRA, R., WILLIAMS, D.W. et al. Adherence and biofilm formation of non-Candida albicans Candida species. In: Trends Microbiol, 2011, no.19, p.241-247. p p 36. MIQUEL, S, LAGRAFEUILLE, R, SOUWEINE, B, FORESTIER, C. Anti-biofilm activity as a health Microbiol., 2016, no7, p.592. doi: 10.3389/fmicb.2016.00592 , , , p 37. BAILLIE, GS., DOUGLAS, L.J. Matrix polymers of Candida biofilms and their possible role in biofilm resistance to antifungal agents. In: J. Antimicrob Chemother, 2000, no46(3), p.397-403. doi:10.1093/jac/46.3.397 g g , , ( ), p j 38. RAMAGE G., MOWAT E., JONES B., WILLIAMS C., LOPEZ-RIBOT, J. Our current understanding of fungal biofilms. In: Crit Rev. Referințe: Al-FATTANI, M.A., DOUGLAS, L.J. Biofilm matrix of Candida albicans and Candida tropicalis: chemical composition and role in drug resistance. In: Journal of Medical Microbiology, 2006, no55, p.999-1008. ISSN 0022- 2615, e-ISSN 1473-5644 , 51. MOWAT, E., WILLIAMS, C., JONES, B., McCHLERY, S., RAMAGE, G. The characteristics of Aspergillus fumigatus mycetoma development: is this a biofilm? In: Medical Mycology, 2009, no47: Suppl 1S, p.120-126. ISSN 1369-3786 52 LOUSSERT C SCHMITT C PREVOST M C BALLOY V FADEL E et al In vivo biofilm composition of 51. MOWAT, E., WILLIAMS, C., JONES, B., McCHLERY, S., RAMAGE, G. The characteristics of Aspe mycetoma development: is this a biofilm? In: Medical Mycology, 2009, no47: Suppl 1S, p.120-126. ISS 51. MOWAT, E., WILLIAMS, C., JONES, B., McCHLERY, S., RAMAGE, G. The characteristics of Aspergillus fumigatus mycetoma development: is this a biofilm? In: Medical Mycology, 2009, no47: Suppl 1S, p.120-126. ISSN 1369-3786 52. LOUSSERT, C., SCHMITT, C., PREVOST, M.C., BALLOY, V., FADEL, E., et al. In vivo biofilm composition of Aspergillus fumigatus. In: Cellular Microbiology, 2010, no.12, p.405-410. mycetoma development: is this a biofilm? In: Medical Mycology, 2009, no47: Suppl 1S, p.120 126. ISSN 1369 3786 52. LOUSSERT, C., SCHMITT, C., PREVOST, M.C., BALLOY, V., FADEL, E., et al. In vivo biofilm composition of Aspergillus fumigatus. In: Cellular Microbiology, 2010, no.12, p.405-410. 53. SINGHAL, D., BAKER, L., WORMALD, P.J., TAN, L. Aspergillus fumigatus biofilm on primary human sinonasal epithelial culture. In: American Journal of Rhinology and Allergy, 2011, no25, p.219-225. ISSN 1945-8924, online ISSN 1945-8932 54. LERMANN, U., MORSCHHAUSER, J. Secreted aspartic proteases are not required for invasion of reconstituted human epithelia by Candida albicans. In: Journal of Microbiology, 2008, no.154, p.3281-3295. Print ISSN 1225- 8873, electronic ISSN 1976-3794 , 55. DAVIS, L.E., COOK, G., COSTERTON, J.W. Biofilm on ventriculo-peritoneal shunt tubing as a cause of treatment failure in coccidioidal meningitis. In: Emerging Infectious Diseasis, 2002, no8, p.376-379. ISSN 1080-6059 , 55. DAVIS, L.E., COOK, G., COSTERTON, J.W. Biofilm on ventriculo-peritoneal shunt tubing as a cause of treatment failure in coccidioidal meningitis. In: Emerging Infectious Diseasis, 2002, no8, p.376-379. ISSN 1080-6059 56. LEAR, G., LEWIS, G.D. Microbial Biofilms: Current Research and Applications. Norfolk: Caister Academic Press, 2012 failure in coccidioidal meningitis. In: Emerging Infectious Diseasis, 2002, no8, p.376-379. ISSN 1080-6059 56. LEAR, G., LEWIS, G.D. Microbial Biofilms: Current Research and Applications. Norfolk: Caister Academic Press, 2012. 56. LEAR, G., LEWIS, G.D. Referințe: Mechanism of fluconazole resistance in Candida albicans biofilms: Phase-specific role of efflux pumps and membrane sterols. In: Infection and Immunity, 2003, no71, p.4333-4340 p 68. SOTO, S.M. Role of efflux pumps in the antibiotic resistance of bacteria embedded in a biofilm. In: Virulence, 2013, no.4, p.223-229. Print ISSN 2150-5594, Online ISSN 2150-5608 69. GEBREYOHANNES, G., NYERERE, A., BII, C., SBHATU, D.B. Challenges of intervention, treatment, and antibiotic resistance of biofilm-forming microorganisms. In: Heliyon, 2019, no5(8), p.e 02192. Published 2019 Aug 19. doi:10.1016/j.heliyon.2019.e02192. ISSN: 2405-8440. j y 70. SHARMA, D., MISBA, L. and KHAN, A.U. Antibiotics versus biofilm: an emerging battleground in microbial communities. In: Antimicrobial Resistance and Infection Control, 2019, no8, p.76. [Accesat: 15.01.2020] Disponibil https://doi.org/10.1186/s13756-019-0533 . ISSN 2047-2994 p g 71. THIEN-FAH, C. Mah, George A. O'TOOLE. Review. Mechanisms of biofilm resistance to antimicrobial agents. In: Trends in Microbiology, 2001, vol.9, Issue 1, p.34-39. [Accesat: 18.04. 2020] Disponibil: https://doi.org/10.1016/S0966-842X(00)01913-2. ISSN 1878-4380 (online) gy p 16/S0966-842X(00)01913-2. ISSN 1878-4380 (onlin 72. SANDAI, D., TABANA, Y.M., OUWEINI, A.E., AYODEJI, I.O. Resistance of Candida albicans Biofilms to Drugs and the Host Immune System. In: Jundishapur Journal of Microbiology, 2016, no.9(11), p. e37385. doi: 10.5812/jjm.37385. ISSN print: 2008-3645, electronic: 2008-4161. p 73. SINGH, S., SINGH, S.K., CHOWDHURY, I., SINGH, R. Understanding the Mechanism of Bacterial Biofilms Resistance to Antimicrobial Agents. In: Open Microbiology Journal, 2017, no11, p.53-62. doi:10.2174/1874285801711010053. ISSN 1874-2858 74. TAFF, H.T., MITCHELL, K.F., EDWARD, J.A., ANDES, D.R. Mechanisms of Candida biofilm drug resistance. In: Future Microbiology, 2013, no8, p.1325-1337. 75. SHUNMUGAPERUMAL, T. Biofilm Eradication and Prevention: A Pharmaceutical Approach to Medical Device Infections. New Jersey: John Wiley & Sons, Inc.; 2010, p.116-151. f y y p 76. McCALL, A.D., PATHIRANA, R.U., PRABHAKAR, A. et al. Candida albicans biofilm development is governed by cooperative attachment and adhesion maintenance proteins. In: npj Biofilms and Microbiomes, 2019, no5, p.21. [Accesat: 12.05.2020] Disponibil: https://doi.org/10.1038/s41522-019-0094-5. ISSN 2055-5008 (online) p p g 77. MOWAT, E., LANG, S., WILLIAMS, C., McCULLOCH, E., JONES, B., RAMAGE, G. Phase-dependent antifungal activityagainst Aspergillus fumigatus developing multicellular filamentous biofilms. In: Journal of Antimicrobial Chemotherapy, 2008, no62, p.1281-1284. py p 78. NIIMI, M., FIRTH, N.A., CANNON, R.D. Antifungal drug resistance of oral fungi. In: Odontology, 2010, no98, p.15-25. 79. RAMAGE, G., RAJENDRAN, R., SHERRY, L., WILLIAMS, C. Fungal biofilm resistance. In: International Journal of Microbiology, 2012, p.521-528. ISSN 1687-918X (Print), ISSN 1687-9198 (Online) 80. CAVALHEIRO, M., TEIXEIRA, M.C. Referințe: Microbial Biofilms: Current Research and Applications. Norfolk: Caister Academic Press, 2012. 57. DAVIES, D.G., MARQUES, C.N. A fatty acid messenger is responsible for inducing dispersion in microbial biofilms. In: Journal of Bacteriology, 2009, no191(5), p.1393-403. Print ISSN 0021-9193, online ISSN 1098-5530 f gy ( ) p 58. GREENBERG, E.P. Bacterial communication and group behavior. In: Journal of Clinical Investigatio p.1288-1290. ISSN 0021-9738 (print), 1558-8238 (online) gy p G, E.P. Bacterial communication and group behavior. In: Journal of Clinical Investigation, 2003, no112, ISSN 0021-9738 (print), 1558-8238 (online) 59. WOLCOTT, R.D., EHRLICH, G.D. Biofilms and chronic infections. In: Journal of the American Medical Association, 2008, no299, p.2682-2684. ISSN 0098-7484 108 Seria “{tiin\e reale [i ale naturii” {tiin\e Biologice ISSN 1814-3237 60. RAMAGE, G., MOWAT, E., JONES, B., WILLIAMS, C., LOPEZ-RIBOT, J. Our current understanding of fungal biofilms. In: Critical Reviews in Microbiology, 2009, no35, p.340-355. ISSN 1040-841X (print); 1549-7828 (web). 61. WONGSUK, T., PUMEESAT, P., LUPLERTLOP, N. Fungal quorum sensing molecules: Role in funga and pathogenicity. In: Journal of Basic Microbiology, 2016, no56, p.440-447. p g y f gy p 62. SARDI, J. de C., PITANGUI, N. de S., RODRIGUEZ-ARELLANES, G., TAYLOR, M.L., FUSCO-ALMEIDA, A.M., MENDES-GIANNINI, M.J. Highlights in pathogenic fungal biofilms. In: Revista Iberoamericana de Micologia, 2014, no31, p.22-29. ISSN 1130-1406 63. ALBUQUERQUE, P., CASADEVALL, A. Quorum sensing in fungi – A review. In: Medical Mycology, 2012, no50, p.337-345. ISSN 1369-3786 63. ALBUQUERQUE, P., CASADEVALL, A. Quorum sensing in fungi A review. In: Medical Mycology, 2012, no50, p.337-345. ISSN 1369-3786 64 DEEP A CHAUDHARY U GUPTA V Quorum sensing and Bacterial Pathogenicity: From Molecules to Disease p 64. DEEP, A., CHAUDHARY, U., GUPTA, V. Quorum sensing and Bacterial Pathogenicity: From Molec In: Journal of Laboratory Physicians, 2011, no3(1), p.4-11. doi: 10.4103/0974-2727.78553. ISSN: 0 ., CHAUDHARY, U., GUPTA, V. Quorum sensing and Bacterial Pathogenicity: From Molecules to Diseas al of Laboratory Physicians, 2011, no3(1), p.4-11. doi: 10.4103/0974-2727.78553. ISSN: 0974-2727. 65. LI, Y.H., TIAN, X. Quorum sensing and bacterial social interactions in p.2519-2538. doi:10.3390/s120302519. ISSN 1424-8220 65. LI, Y.H., TIAN, X. Quorum sensing and bacterial social interactions in biofilms. In: Sensors (Basel), 2012, no12(3), p.2519-2538. doi:10.3390/s120302519. ISSN 1424-8220 p 66. LEWIS, K. Persister cells: Molecular mechanisms related to antibiotic tolerance. In: Handbook of Experimental Pharmacology, 2012, p.121-133. ISSN 0171-2004 gy, , p 67. MUKHERJEE, P.K., CHANDRA, J., KUHN, D.M., GHANNOUM, M.A. g py p . RODRIGUES, M.E. et al. Candida spp./Bacteria Mixed Biofilms. In: Journal of Fungi, 2020, no6, p.5; doi:10.3390/jof6010005. ISSN 2309-608X Referințe: Candida Biofilms: Threats, Challenges, and Promising Strategies. In: Frontiers in Medicine (Lausanne), 2018, no5, p.28. Pdoi:10.3389/fmed.2018.00028. ISSN: 2095-0217 (print), 2095- 0225 (web) 81. CHANDRA, J., MUKHERJEE, P.K., LEIDICH, S.D. et al. Antifungal resistance of candidal biofilms formed on denture acrylic in vitro. In: Journal of Dental Research, 2001, no80(3), p.903-908. y f ( ) p 82. LaFLEUR, M.D., KUMAMOTO, C.A., LEWIS, K. Candida albicans biofilms produce antifungal-t cells. In: Antimicrobial Agents and Chemotherapy, 2006, no50, p.3839-3846. 83. RODRIGUES, M.E. et al. Candida spp./Bacteria Mixed Biofilms. In: Journal of Fungi, 2020, no6, p.5; doi:10.3390/jof6010005. ISSN 2309-608X 109 S T U D I A U N I V E R S I T A T I S M O L D A V I A E Revist= [tiin\ific= a Universit=\ii de Stat din Moldova, 2020, nr.1(131) 84. LEWIS, K.I.M. Riddle of biofilm resistance. In: Antimicrobial Agents and Chemotherapy, 2001, no45, p.999-1007. doi:10.1128/AAC.45.4.999-1007.2001. Print ISSN 0066-4804, online ISSN 1098-6596 85. LEBEAUX, D., GHIGO, J.M., BELOIN, C. Biofilm-related infections: bridging the gap between clinical management and fundamental aspects of recalcitrance toward antibiotics. In: Microbiology and Molecular Biology Reviews, 2014, no78(3), p.510-543. ( ) p 86. MARTINS, M., UPPULURI, P., THOMAS, D.P., CLEARY, I.A., HENRIQUES, M., LOPEZ-RIBOT, J.L., et al. Presence of extracellular DNA in the Candida albicans biofilm matrix and its contribution to biofilms. In: Mycopathologia, 2010, no169, p.323-31. 87. COENYE, T., BRACKMAN, G., RIGOLE, P., et al. Eradication of Propionibacterium acnes biofilms by plant extracts and putative identification of icariin, resveratrol and salidroside as active compounds. In: Phytomedicine, 2012, no19, p.409-412. p 88. CRAGG, G.M., NEWMAN, D.J. Natural products: a continuing source of novel drug leads. In: Biochimica et Biophysica Acta, 2013, no1830(6), p.3670-3695. 89. BORCHARDT, J.K. The Beginnings of Drug Therapy: Ancient Mesopotamian Medicine. In: Drug News and Perspectives, 2002, no15(3), p.187-192. ISSN 0214-0934 90. DEV, S. Ancient-modern concordance in Ayurvedic plants: some examples. In: Environmental Health Perspectives, 1999, no107(10), p.783-9. ISSN 0091-6765 (print); 1552-9924 (web) 90. DEV, S. Ancient-modern concordance in Ayurvedic plants: some examples. In: Environment 1999, no107(10), p.783-9. ISSN 0091-6765 (print); 1552-9924 (web) y p p 1999, no107(10), p.783-9. ISSN 0091-6765 (print); 1552-9924 (web) 91. BINK, A., PELLENS, K., CAMMUE, B.P., THEVISSEN, K. Anti-biofilm strategies: How to eradicate Candida biofilms? In: Open Microbiology Journal, 2011, no5, p.29-38. ISSN 1874-2858 p gy p W., TIAN, Z., et al. Developing natural products as potential anti-biofilm agents. In: Chinese Medical 9, no14, p.11. 92. LU, L., Hu, W., TIAN, Z., et al. Developing natural products as potential anti-biofilm agents. In: C Journal, 2019, no14, p.11. 93. SHAHID, M., SHAHZAD, A., SOBIA, F., et al. Plant natural products as a potential source for antibacterial agents: recent trends. În: Anti-Infective Agents in Medicinal Chemistry, 2009, no8, p.211-225. ISSN (Print) 1871-5214, ISSN (Online) 1875-6018 Date despre autor: Date despre autor: Olga BURDUNIUC, doctor în ştiinţe medicale, conferenţiar universitar, USMF „Nicolae Testemiţanu”; șef laborator Microbiologie, Agenţia Naţională pentru Sănătate Publică. E-mail: olgaburduniuc3@gmail.com ORCID: 0000-0002-6944-0800 E-mail: olgaburduniuc3@gmail.com ORCID: 0000-0002-6944-0800 E-mail: olgaburduniuc3@gmail.com ORCID: 0000-0002-6944-0800 Prezentat la 29.06.2020 110
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COMPORTAMENTO E EFEITO DO TITÂNIO DURANTE O PROCESSAMENTO DE UM MINÉRIO DE FERRO
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TURRER ET AL. (2014) DOI: http://dx.doi.org/10.15628/holos.2014.1761 DOI: http://dx.doi.org/10.15628/holos.2014.1761 RESUMO realização de testes em laboratório que simulassem o processo produtivo industrial. Testes de flotação mostraram que a recuperação desse elemento é proporcional a do ferro, indicando associação da hematita com o titânio. As análises em microscópio ótico não foram capazes de identificar minerais portadores de titânio, reforçando a hipótese anterior. Por fim, os teores de dióxido de titânio obtidos no concentrado foram usados para estimar a qualidade esperada do pellet feed. Os resultados mostraram que o teor de dióxido de titânio no concentrado ficou abaixo dos limites exigidos pelo mercado. O minério de ferro da Serra do Sapo possui características diferentes daqueles oriundos dos mais importantes polos produtores brasileiros, uma vez que foi formado em condições geológicas distintas. Uma característica que o difere é o seu teor de titânio, que alcança valores pouco usuais em algumas regiões do depósito. Este trabalho objetivou verificar o comportamento desse elemento no tratamento de minérios e seu possível efeito nos processos subsequentes da cadeia produtiva do aço. Inicialmente, foi realizada uma revisão bibliográfica sobre o assunto. Em seguida, foram coletadas amostras da região de maior concentração desse elemento para PALAVRAS-CHAVE: minério de ferro, flotação, pellet feed, titânio. KEYWORDS: iron ore, flotation, pellet feed, titanium. H. D. G. TURRER1, K. B. MENEZES, C. R. MAGALHÃES, F. H. P. GONZAGA, J. C. SILVA, J. A. ALMEIDA e C. M. NASCIMENTO ¹Gerência de Controle de Qualidade e Desenvolvimento de Processos do Minas-Rio - Anglo American henrique.turrer@angloamerican.com Artigo submetido em novembro/2013 e aceito em janeiro/2014 Artigo submetido em novembro/2013 e aceito em janeiro/2014 1 INTRODUÇÃO O depósito da Serra do Sapo, localizado no município de Conceição do Mato Dentro, MG, possui, até o momento, aproximadamente 5 bilhões de toneladas de recursos geológicos. A partir desse minério serão produzidos 26,5 milhões de toneladas naturais de pellet feed por ano. O processo produtivo contemplará a extração do minério por escavadeiras e caminhões, fragmentação por britadores de mandíbulas e cônicos, prensas de rolos e moinhos de bolas, seguido por deslamagem, flotação, remoagem em moinhos verticais, espessamento, bombeamento por 525 km de mineroduto e separação sólido-liquido para embarque. A reserva, com mais de 1 bilhão de toneladas de minério de ferro, formará uma cava que se estenderá por mais de 12 quilômetros na direção norte-sul. Foi observado que em algumas regiões do depósito, onde a operação de lavra foi planejada para ter início, a concentração de titânio é pouco usual comparado à média dos minérios de ferro brasileiros. Por isso, este trabalhou objetivou verificar o comportamento desse elemento no tratamento do minério e seu possível efeito nos processos subsequentes da cadeia produtiva do aço. Inicialmente foi feita uma revisão bibliográfica em busca de informações que pudessem guiar e suportar as avaliações experimentais. Em seguida, foram realizados testes em escala de laboratório que simulassem o processo produtivo para prever o comportamento do óxido de titânio durante seu futuro processamento industrial. TURRER ET AL. (2014) HOLOS, Ano 30, Vol. 3 - Edição Especial - XXV ENTMME / VII MSHNT ABSTRACT were collected to perform laboratory tests to simulate the industrial process. Flotation tests showed that titanium recovery is proportional to iron recovery, indicating association with hematite. Optical microscopy analysis could not identify titanium minerals, reinforcing the previous hypothesis. Lastly, the titanium dioxide amount in the concentrates was used to estimate the pellet feed quality. The results showed that concentrate titanium dioxide content will be below the usual limits requested by the market. Iron ore from Serra do Sapo’s deposit has distinct characteristics from the ones exploited in the main Brazilian iron ore production poles since it was formed in different geological conditions. One of these characteristics is the titanium amount, which presents unusual values in some regions of the deposit. This work aimed verifies this element behavior during the mineral processing and its effect in the steelmaking following process. Initially, a bibliographic revision about the subject was performed. Subsequently, ore samples from the region where this element concentration is higher 203 HOLOS, Ano 30, Vol. 3 - Edição Especial - XXV ENTMME / VII MSHNT HOLOS, Ano 30, Vol. 3 - Edição Especial - XXV ENTMME / VII MSHNT TURRER ET AL. (2014) para que isso ocorra, é de 0,112 e 0,196% em 1.400 e 1.500 °C, respectivamente [5]. Contudo, a presença do mesmo apresenta um efeito positivo ao processo, pois promove a formação de uma camada protetora no refratário, elevando sua vida útil. Estudos mostram que adições de 15 até 20 kg/t de gusa são necessários para que porções de carbonidretos de titânio sejam mantidos no forno e atuem na proteção dos refratários, uma vez que boa parte do cristais de titânio, precipitados no gusa líquido, são arrastados em direção aos canais de corrida durante o vazamento [6]. Entretanto, essa quantidade pode variar em função da estrutura mineralógica do portador do titânio, pois menores quantidades do mesmo são necessárias quando este se encontra em condições termodinamicamente mais favoráveis [7]. No aço, o titânio eleva a resistência e a dureza, mas diminuiu a ductibilidade. Essas propriedades apresentam uma repentina mudança de comportamento quando o teor de titânio é maior que 0,115% no gusa, fato atribuído à precipitação do mesmo [8]. Poucos estudos são encontrados sobre o efeito de minerais portadores de titânio no processamento mineral. Em um deles, a concentração de várias amostras provenientes de dois depósitos de minério de ferro na Suécia foi avaliada. Ao todo, 172 amostras foram tratadas, produzindo concentrados com TiO2 variando de 0,002 até 0,399% com média de 0,059%. Isso permitiu determinar a média dos concentrados oriundos dos dois depósitos como sendo igual a 0,054 e 0,096%. O autor atribui a presença de titânio a diferentes minerais, já que a relação entre TiO2 e Al2O3 nas amostras antes do tratamento não era constante. Foi ainda afirmado que os valores de TiO2 das amostras de concentrado estão bem abaixo dos limites máximos exigidos para pelotas de redução direta, que são fornecidas pela empresa exploradora do depósito, com exceção de pequenas partes onde outras técnicas de processamento poderiam ser necessárias [9]. Em se tratando de minérios brasileiros, foi possível obter alguns indicativos do comportamento do óxido de titânio em trabalhos que não tinham esse tópico como um dos objetivos, mas reportaram resultados dos teores de TiO2 nos produtos, possibilitando essa avaliação. Os minerais portadores de titânio tiveram uma maior recuperação no concentrado da etapa de flotação da usina de Brucutu, de propriedade da Vale S.A. 2 REVISÃO BIBLIOGRÁFICA A apresentação das referências encontradas será feita na ordem inversa do processamento do minério. Iniciará com questões relativas ao titânio na siderurgia, passando pelo tratamento de minério e, por fim, abordará sua forma de ocorrência em alguns depósitos. A presença de elevadas quantidades de titânio no pellet feed pode ser prejudicial para os processos de redução do óxido de ferro à ferro metálico. Grande parte dos estudos sobre esse assunto é relativa a depósitos de minério de ferro com origem completamente diferente daquele da Serra do Sapo, que possuem titanomagnetita, apresentando um teor de titânio na ordem de 7% [1,2]. Durante o processo de pelotização, o titânio pode alterar as propriedades da pelota através da difusão na rede da hematita, com geração de trincas ao longo da matriz do aglomerado. Em solução sólida, o titânio também promove uma aceleração da taxa de oxidação da magnetita para hematita [3]. Fornecedores de módulo de redução direta associam o teor de titânio da pelota ao inchamento da mesma. Por isso, sugerem adoção de limites máximos de especificação para evitar a ocorrência de cachos, que diminuem a permeabilidade do leito [4]. No alto forno, o óxido de titânio é reduzido gerando compostos estáveis, chamados de carbonidretos de titânio, ou Ti(N,C), com pontos de fusão muito elevados, que aumentam a viscosidade das fases em que se encontram. Dependendo da temperatura e da quantidade de titânio, esses compostos podem se precipitar na forma sólida. Com isso, o vazamento da escoria e do gusa se tornam muito mais complexos. A concentração mínima de óxido de titânio no gusa, HOLOS, Ano 30, Vol. 3 - Edição Especial - XXV ENTMME / VII MSHNT 204 Nos resultados apresentados, o teor de titânio na alimentação dessa etapa foi, em dois momentos distintos, de 0,047 e 0,039%, enquanto no concentrado o teor foi de, respectivamente, 0,131 e 0,122% [10]. Minério de ferro hematítico, com elevado grau de hidratação, abaixo de 0,15 mm e contendo elevado teor de ferro, 58,7%, apresentou teor de titânio igual a 0,139% [11]. Testes de concentração de flotação em bancada com minério anfibolítico também resultaram numa elevada concentração do titânio no concentrado. O TiO2 dessa amostra subiu de 0,01% na alimentação da concentração para 0,10% no concentrado de duas flotações, catiônica reversa e aniônica direta [12]. Testes de concentração magnética com materiais abaixo de 1,0 mm, provenientes de barragem de rejeitos da usina de Córrego do Feijão, no Quadrilátero Ferrífero, resultaram em concentrados com TiO2 de 0,063 e 0,054%. Nesses testes, a recuperação de titânio no concentrado foi perto de 30% [13]. Minérios provenientes das minas de Jangada, João Pereira, Fábrica Nova e Serra Serpentina, todas localizadas no Quadrilátero Ferrífero, apresentaram TiO2 de, respectivamente, 0,016, 0,033, 0,023 e 0,036% no ROM. Contudo, os teores no concentrado não foram reportados [14]. Titânio foi identificado em finas lamelas, de 5 até 0,2 μm, dispostas em planos cristalinos da estrutura dos óxidos de ferro em concentrados magnéticos brasileiros com teor de TiO2 de 3,16 e 2,51%. Apesar da difração de raios X não ter detectado nenhum mineral de titânio, a análise em HOLOS, Ano 30, Vol. 3 - Edição Especial - XXV ENTMME / VII MSHNT 205 TURRER ET AL. (2014) microscópio de luz refletida permitiu a identificação de três formas de ocorrência de ilmenita: exsolução com magnetita, cristais em contato com magnetita e cristais individuais [15]. microscópio de luz refletida permitiu a identificação de três formas de ocorrência de ilmenita: exsolução com magnetita, cristais em contato com magnetita e cristais individuais [15]. A caracterização de um minério intemperizado, proveniente da mina de Alegria no Quadrilátero ferrífero, mostrou que o titânio encontrado nas amostras de goethita apresentava teores diversos, independente de sua textura e seu grau de cristalinidade, e estaria alojado dentro da estrutura cristalográfica da goethita. Também foi identificada a presença de fases intermediárias da solução sólida hematita-ilmenita [16]. Cinquenta e nove amostras de granulados provenientes de diferentes minas do Quadrilátero foram caracterizadas. O teor médio de TiO2 foi de 0,050%, variando numa ampla faixa, de 0,010 até 0,201%. O autor identificou poros preenchidos por um plasma goethítico- hematítico nas amostras mais superficiais com altos valores de alumínio e titânio. Além disso, a proximidade com os cristais de magnetita permitiu concluir que esses plasmas goethítico- hematíticos possuíam uma origem supergênica. O teor de 0,201% de TiO2 em uma amostra foi atribuído a associação com rochas básicas e a alteração supergênica concentrou o elemento no minério mais superficial. Por fim, concluiu-se que o titânio é mais elevado nas tipologias associadas à canga e, secundariamente, nas tipologias porosas, itabiríticas e protominério, relacionado aos eventos genéticos de alteração supergênica [17]. O teor de titânio não é um item contratual de especificação usual para o pellet feed. O pellet feed produzido a partir de minérios do Quadrilátero Ferrífero, e exportado, não apresentam teores de titânio em sua especificação, porém, pelotas produzidas a partir do mesmo minério apresentam um teor máximo de TiO2 que pode variar de 0,038 a 0,045% [18]. O teor máximo de óxido de titânio máximo da especificação de sinter feed produzidos a partir de três diferentes minas australianas varia de 0,08 a 0,09% [19]. 3 MATERIAL E MÉTODOS As amostras de minério de ferro foram obtidas através de sondagem de circulação reversa, com broca de diâmetro igual a 50,5 ou 63,5 mm. Ao todo foram realizados 27 furos, totalizando 1.478 metros. A amostra foi dividida em quarteador rotativo, de forma que um quarto de cada amostra foi usado para compor as amostras de teste. As amostras foram compostas em intervalos de 15 m aproximadamente. A moagem do material foi realizada segundo procedimentos internos até obtenção de 90% passante na malha de 0,150 mm, o que permitiu a determinação do consumo energético da moagem primária. O produto da moagem foi deslamado em ciclone piloto com diâmetro de 2”, apex e vortex de 4,8 e 13 mm, respectivamente,. Na deslamagem, solução de soda cáustica foi adicionada até que a polpa, com 17% de sólidos em peso, atingisse o pH de 11. A velocidade de bombeamento foi ajustada até a produção de um underflow com 50% de sólidos em peso. Os testes de flotação foram realizados em cuba de 4,5 l com percentual de sólidos no condicionamento e na flotação ajustados em 60 e 40%, respectivamente,. Foram utilizadas soluções a 1% de amina EDA-C da Clariant e amido de milho da Kowaslki. Amido foi gelatinizado com soda cáustica na relação de 5:1 e dosado em somente um nível. O pH da polpa foi ajustado para 10,5 com soda cáustica. O amido foi condicionado por 5 minutos antes da adição da amina, que foi condicionada por 1 minuto. A agitação foi controlada em 1.300 e 1.500 rpm, no HOLOS, Ano 30, Vol. 3 - Edição Especial - XXV ENTMME / VII MSHNT 206 TURRER ET AL. (2014) condicionamento e na flotação, respectivamente. A coleta do material flotado aconteceu por 6 minutos após inicio da aeração. Os resultados foram reconciliados com programa de balanço de massas Bilco. condicionamento e na flotação, respectivamente. A coleta do material flotado aconteceu por 6 minutos após inicio da aeração. Os resultados foram reconciliados com programa de balanço de massas Bilco. Ensaios granulométricos à úmido foram realizados em vibrador suspenso com peneiras da série Tyler. Os ensaios para determinação da composição química das amostras foram realizados por fluorescência de raios X de pó prensado ou, em alguns casos, de pastilha fundida com equipamento Axios da Panalytical. A perda ao fogo foi determinada por calcinação em mufla, a 1.100 °C. 3 MATERIAL E MÉTODOS Análise mineralógica foi conduzida em microscópio ótico Olympus BX51TRF com magnificação máxima de 200 vezes. TURRER ET AL. (2014) TURRER ET AL. (2014) Não foram observadas, Figura 3, altas correlações entre o teor de óxido de titânio no minério e seu desempenho na flotação, indicando que esse fator não tem forte efeito no desempenho dessa etapa. Figura 2 - Comportamento do titânio durante o processamento do minério: recuperações em função da tipologia (a) e correlação de teor no minério e no concentrado (b). Litotipo Concentrado Lama QF IFX IF HM CGM QF IFX IF HM CGM 100 80 60 40 20 0 %RTiO2 6,0 6,5 6,8 8,3 18,3 6,0 6,5 6,8 8,3 18,3 6,0 6,5 6,8 8,3 18,3 75,9 55,4 78,8 89,5 63,0 75,9 55,4 78,8 89,5 63,0 75,9 55,4 78,8 89,5 63,0 0,30 0,25 0,20 0,15 0,10 0,05 0,00 0,4 0,3 0,2 0,1 0,0 %TiO2_rom %TiO2_concentrado S 0,0352399 R-Sq 76,3% R-Sq(adj) 76,0% Regression 95% CI TiO2_c70 = 0,03307 + 1,059 TiO2_rom Fitted Line Plot %SiO2_c70 = - 0,0598 + 7,893 TiO2_rom Fitted Line Plot %RM = 42,44 + 51,79 TiO2_rom Fitted Line Plot %RFe = 81,05 - 76,49 TiO2_rom a) b) Litotipo Concentrado Lama QF IFX IF HM CGM QF IFX IF HM CGM 100 80 60 40 20 0 %RTiO2 6,0 6,5 6,8 8,3 18,3 6,0 6,5 6,8 8,3 18,3 6,0 6,5 6,8 8,3 18,3 75,9 55,4 78,8 89,5 63,0 75,9 55,4 78,8 89,5 63,0 75,9 55,4 78,8 89,5 63,0 Fitted Line Plot %SiO2_c70 = - 0,0598 + 7,893 TiO2_rom Fitted Line Plot %RM = 42,44 + 51,79 TiO2_ro a) 0,30 0,25 0,20 0,15 0,10 0,05 0,00 0,4 0,3 0,2 0,1 0,0 %TiO2_rom %TiO2_concentrado S 0,0352399 R-Sq 76,3% R-Sq(adj) 76,0% Regression 95% CI TiO2_c70 = 0,03307 + 1,059 TiO2_rom m Fitted Line Plot %RFe = 81,05 - 76,49 TiO2_rom b) Figura 2 - Comportamento do titânio durante o processamento do minério: recuperações em função da tipologia (a) e correlação de teor no minério e no concentrado (b). Figura 3 - Efeito do teor de titânio no ROM no desempenho (sílica no concentrado, recuperação mássica e metalúrgica) no processamento do minério. 4 RESULTADOS E DISCUSSÕES As amostras foram classificadas tipologicamente segundo os teores de ferro, fósforo e alumina, além da descrição visual do testemunho. Grande parte das amostras foi classificada como itabirito friável (IF), com pequena participação de cangas mineralizadas (CGM), localizadas nas porções superficiais dos furos, seguido de quartzito ferruginoso (QF), itabirito friável com alta alumina (IFX) e hematita (HM). As amostras de IFX e CGM apresentaram teores de óxido de titânio maior que as demais, com exceção de algumas poucas classificadas como IF, Figura 1a. Além disso, foi observada uma nítida correlação entre o teor de alumina e de óxido de titânio nas amostras de minério, Figura 1b. Suspeita-se que o titânio esteja presente em minerais associados a intrusões do manto de rochas meta-diabásicas ricas em alumina e titânio durante os eventos de formação do depósito. Figura 1 - Teores de óxido de titânio das amostras avaliadas, classificadas em função da litologia (a) e em função do teor de alumínio das mesmas (b). QF IFX IF HM CGM 0,30 0,25 0,20 0,15 0,10 0,05 0,00 Litotipo %TiO2_rom 0,046 0,246 0,052 0,059 0,158 10 8 6 4 2 0 0,35 0,30 0,25 0,20 0,15 0,10 0,05 0,00 %Al2O3_rom %TiO2_rom CGM HM IF IFX QF Litologia R2 = 77,4 %TiO 2_rom = 0,008972 + 0,03415 x %A l2O 3_rom a) b) 10 8 6 4 2 0 0,35 0,30 0,25 0,20 0,15 0,10 0,05 0,00 %Al2O3_rom %TiO2_rom CGM HM IF IFX QF Litologia R2 = 77,4 %TiO 2_rom = 0,008972 + 0,03415 x %A l2O 3_rom b) Figura 1 - Teores de óxido de titânio das amostras avaliadas, classificadas em função da litologia (a) e em função do teor de alumínio das mesmas (b). Grande parte do titânio alimentado foi recuperado no concentrado, Figura 2a. Somente a canga apresentou uma maior recuperação desse elemento nas lamas. Contudo, essa tipologia foi a que apresentou uma maior perda de massa nas lamas também. Foi comprovado, através de análise de variância e pela correlação da Figura 2b, que o teor de titânio no minério tem um grande efeito no seu teor no concentrado. HOLOS, Ano 30, Vol. 3 - Edição Especial - XXV ENTMME / VII MSHNT 207 TURRER ET AL. (2014) 0,30 0,15 0,00 6 5 4 3 2 1 0 -1 -2 TiO2_rom %SiO2_c70 S 0,677308 R-Sq 32,6% R-Sq(adj) 31,8% Regression 95% CI 95% PI 0,30 0,15 0,00 90 80 70 60 50 40 30 20 10 TiO2_rom %RM S 13,5570 R-Sq 4,9% R-Sq(adj) 3,8% 0,30 0,15 0,00 100 90 80 70 60 50 40 30 TiO2_rom %RFe S 10,2564 R-Sq 16,5% R-Sq(adj) 15,6% 0,30 0,15 0,00 6 5 4 3 2 1 0 -1 -2 TiO2_rom %SiO2_c70 S 0,677308 R-Sq 32,6% R-Sq(adj) 31,8% Regression 95% CI 95% PI 0,30 0,15 0,00 90 80 70 60 50 40 30 20 10 TiO2_rom %RM S 13,5570 R-Sq 4,9% R-Sq(adj) 3,8% 0,30 0,15 0,00 100 90 80 70 60 50 40 30 TiO2_rom %RFe S 10,2564 R-Sq 16,5% R-Sq(adj) 15,6% Figura 3 - Efeito do teor de titânio no ROM no desempenho (sílica no concentrado, recuperação mássica e metalúrgica) no processamento do minério. Algumas das amostras testadas sequer seriam consideradas minérios, por exibirem teores de alumina elevados, maior que 8%, e baixo teor de ferro, menor que 25%. Por isso, as mesmas não seriam direcionadas para usina de tratamento, mesmo em pequenas proporções. Ainda assim, a média das amostras restantes não representa a média de toda a região de onde elas foram extraídas. Para a determinação desse valor, as massas representativas de cada amostra no depósito deveriam ser consideradas para determinação da média ponderada, como feito por Abongwa [9]. Uma vez que ainda não é possível determinar as massas representativas, é aconselhável que somente as amostras de IF, que serão alimentadas em grandes proporções na usina, sejam consideradas para projeção da qualidade média do concentrado. As amostras de IF apresentaram qualidade média do ROM e do concentrado muito próxima do planejado. Contudo, observa-se que algumas poucas amostras, 25% do total, estão com valores mais elevados. Em casos HOLOS, Ano 30, Vol. 3 - Edição Especial - XXV ENTMME / VII MSHNT 208 TURRER ET AL. (2014) como esse, em que a variabilidade das amostras é elevada, valores extremos podem influenciar muito a média. Nesses casos, a mediana se torna uma medida descritiva mais adequada para as amostras [20]. Uma forma de quantificar a variabilidade é através do coeficiente de variação, razão entre o desvio padrão e média. Quando o mesmo for superior a 20%, é aconselhável que a mediana seja usada para representar a população. TURRER ET AL. (2014) As amostras apresentaram um coeficiente de variação de 57% para o TiO2 no concentrado e uma mediana de 0,077%. como esse, em que a variabilidade das amostras é elevada, valores extremos podem influenciar muito a média. Nesses casos, a mediana se torna uma medida descritiva mais adequada para as amostras [20]. Uma forma de quantificar a variabilidade é através do coeficiente de variação, razão entre o desvio padrão e média. Quando o mesmo for superior a 20%, é aconselhável que a mediana seja usada para representar a população. As amostras apresentaram um coeficiente de variação de 57% para o TiO2 no concentrado e uma mediana de 0,077%. Por fim, foram realizadas análises mineralógicas em busca da identificação do mineral portador de titânio em duas amostras, uma de IF e outra de IFX, que apresentaram elevado teor de titânio no ROM e no concentrado com morfologia distinta, Tabela I. Tabela I - Composição química das amostras analisadas em microscópio Tipologia Composição do minério (%) Composição do concentrado (%) Fe Al2O3 SiO2 P TiO2 Fe Al2O3 SiO2 P TiO2 IFX 53,5 8,01 14,2 0,111 0,287 67,2 1,07 0,7 0,044 0,282 IF 45,3 3,52 29,3 0,067 0,204 67,2 0,49 2,4 0,054 0,308 A análise das imagens geradas por microscópio eletrônico não permitiu a identificação de nenhum mineral portador de titânio, como titanita ou ilmenita, indicando que o titânio poderia estar presente na estrutura cristalina do mineral de ferro. Essa hipótese só poderá ser comprovada com a utilização de outras técnicas de caracterização, como microscopia eletrônica de varredura aliada a espectroscopia de energia dispersiva, como realizado por Rocha [16]. Contudo, optou-se por não prosseguir com uma caracterização mais detalhada, uma vez que o objetivo principal do estudo não era a caracterização da fonte de titânio e o mesmo não apresentou efeito significativo no desempenho do processamento mineral e nem na qualidade final do concentrado. Na Figura 4, um exemplo das imagens obtidas, é possível identificar uma série de óxidos de ferro e quartzo, mas nenhum mineral de titânio. Figura 4 - Imagem obtida em microscópio de concentrado (IF) com elevado teor de titânio. Figura 4 - Imagem obtida em microscópio de concentrado (IF) com elevado teor de titânio. 6 AGRADECIMENTOS Os autores gostariam de registrar o agradecimento aos colegas de Anglo American Aguinaldo Pereira Sander, Junio Simões Pereira, Marcelo de Castro, Naldio da Silva Vertelo, Rodrigo Faustino Gomes pela dedicação, esforço e comprometimento na realização dos testes e análises. 7 REFERÊNCIAS BIBLIOGRÁFICAS 1. PARK, P.; OSTROVSKI, O. Reduction of Titania–Ferrous Ore by Carbon Monoxide. ISIJ International, v. 43, n.9, p.1316-1325, 2003. 1. PARK, P.; OSTROVSKI, O. Reduction of Titania–Ferrous Ore by Carbon Monoxide. ISIJ International, v. 43, n.9, p.1316-1325, 2003. 2. PARK, P.; OSTROVSKI, O. Reduction of Titania–Ferrous Ore by Hydrogen. ISIJ International, v.44, n.6, p.999-1005, 2004. 2. PARK, P.; OSTROVSKI, O. Reduction of Titania–Ferrous Ore by Hydrogen. ISIJ International, v.44, n.6, p.999-1005, 2004. 3. BUDZIK, R. The balance of titanium and vanadium in the blast furnace with the use of sinter containing a titanium-vanadium-magnetite concentrate. Metalurgia, v. 46, n. 2, p.145-147, 2007 apud Domingues, A. L. A.; Scudeller, L. A. M.; Pereira, A. S. G. Caracterização mineralógica de concentrado magnetítico com presença de titânio e bário. In: Anais do 41º Seminário de Redução de Minério de Ferro e Matérias-primas e 12º Seminário Brasileiro de Minério de Ferro. p.928-939, 2011. 3. BUDZIK, R. The balance of titanium and vanadium in the blast furnace with the use of sinter containing a titanium-vanadium-magnetite concentrate. Metalurgia, v. 46, n. 2, p.145-147, 2007 apud Domingues, A. L. A.; Scudeller, L. A. M.; Pereira, A. S. G. Caracterização mineralógica de concentrado magnetítico com presença de titânio e bário. In: Anais do 41º Seminário de Redução de Minério de Ferro e Matérias-primas e 12º Seminário Brasileiro de Minério de Ferro. p.928-939, 2011. 4. HYL. Disponível em <http://www.energiron.com/Tour/HYL%20DR-Minimill%20QTVR%20tour /start.html> Acessado em: 08/01/2013. 5. WU, J.Y.; HO, C.K. Investigation of Titanium Compound Formation in the Blast Furnace Hearth. China Steel Technical Report, n.22, p.23-28, 2009. 6. PEREIRA, J.L.G.; CAMPANHOLO, B.A.; SILVA, M.B.L.; SILVA, A.L.; SILVA, R.B.L. Titanium Goiás – Decades of experience in marketing of ilmenite for blast furnaces in Brazil. In: Proceedings of 6th International Congress on the Science and Technology of Ironmaking, 42nd International Meeting on Ironmaking and 13th International Symposium on Iron Ore, p.642-657, 2012. 7. MANSO, G.A.C.; SANTOS, G.S.; OLIVEIRA, M.A.G.; FERNANDES, M.V.; AMIRZADEH-ASL, D.; FÜNDERS, D. Preservação do cadinho do alto forno 3 da Usiminas com injeção de titânio sintético. In: Anais do 41º Seminário de Redução de Minério de Ferro e Matérias-primas e 12º Seminário Brasileiro de Minério de Ferro, p.533-543, 2011. 8. OKANO, A.N. Influência do titânio na microestrutura e propriedades mecânicas de um aço C- Mn microligado com 0,08 a 0,16% de titânio produzindo em tiras laminadas a quente. 5 CONCLUSÕES O teor de dióxido de titânio no ROM é diretamente proporcional ao teor de alumina. A média de TiO2 das amostras analisadas é igual a 0,069%. O titânio é recuperado preferencialmente HOLOS, Ano 30, Vol. 3 - Edição Especial - XXV ENTMME / VII MSHNT 209 TURRER ET AL. (2014) no concentrado, ou, em outras palavras, 76% do TiO2 alimentado foi, em média, recuperado no concentrado. O teor de titânio no ROM não afetou o desempenho do processamento mineral. Foi possível estimar o teor médio de TiO2 no concentrado do minério extraído da região como sendo igual a 0,077%. Não foram identificados minerais portadores de titânio. no concentrado, ou, em outras palavras, 76% do TiO2 alimentado foi, em média, recuperado no concentrado. O teor de titânio no ROM não afetou o desempenho do processamento mineral. Foi possível estimar o teor médio de TiO2 no concentrado do minério extraído da região como sendo igual a 0,077%. Não foram identificados minerais portadores de titânio. TURRER ET AL. (2014) 126p., 2009. 126p., 2009. 10. SALES, C. G.;LIPPER, G.;PAULA, N. N.;PEREIRA, J. M.;ROBERTO, J. B.; FONSECA, A.;MACHADO, B. H. Otimização do circuito de flotação reversa de minério de ferro da usina de concentração de Brucutu. In: Anais do 40º Seminário de Redução de Minério de Ferro e Matérias-primas e 11º Seminário Brasileiro de Minério de Ferro, p.111-118, 2010. 11. TOTOU, A.R. Efeito da dispersão em polpas de minérios hematíticos com elevado grau de hidratação. In: Anais do 40º Seminário de Redução de Minério de Ferro e Matérias-primas e 11º Seminário Brasileiro de Minério de Ferro, p.186-194, 2010. 11. TOTOU, A.R. Efeito da dispersão em polpas de minérios hematíticos com elevado grau de hidratação. In: Anais do 40º Seminário de Redução de Minério de Ferro e Matérias-primas e 11º Seminário Brasileiro de Minério de Ferro, p.186-194, 2010. 12. SANTOS; D.F.; VIANA, P.R.M.; ARAUJO, A.C.; SANTOS, J.G.; TEIXEIRA, H.G. Flotação de minérios de ferro anfibolíticos – uma revisão. In: Anais do 39º Seminário de Redução de Minério de Ferro e Matérias-primas e 10º Seminário Brasileiro de Minério de Ferro, 10p., 2009. 13. ZAPPAROLI, A.C.; GUIMARÃES, N.C.; PIRET, W.; CALIXTO, M.; PAULA, C.J.; BENTO, P.; SIMÕES, H.G. Reaproveitamento de depósitos de rejeitos de minério de ferro nos sistemas sul e sudeste da vale: exemplo da barragem de córrego do feijão. Anais do 39º Seminário de Redução de Minério de Ferro e Matérias-primas e 10º Seminário Brasileiro de Minério de Ferro, 12p., 2009. 14. LIMA, R.M.F.; LOPES, G.M.; GONTIJO, C.F. Flotação inversa de minérios de ferro de baixos teores do quadrilátero ferrífero – MG. In: Anais do 40º Seminário de Redução de Minério de Ferro e Matérias-primas e 11º Seminário Brasileiro de Minério de Ferro, p.155-164, 2010. 15. DOMINGUES, A.L.A.; SCUDELLER, L.A.M.; PEREIRA, A.S.G. Caracterização mineralógica de concentrado magnetítico com presença de titânio e bário. In: Anais do 41º Seminário de Redução de Minério de Ferro e Matérias-primas e 12º Seminário Brasileiro de Minério de Ferro, p.928-939, 2011. 16. ROCHA, J.M.P. Caracterização Mineralógica de minérios goethíticos-limoníticos da mina de Alegria, MG. Dissertação de Mestrado em Engenharia Metalúrgica e de Minas da Escola de Engenharia da UFMG, 263p., 1997. 17. FERNANDES, E.Z. Caracterização física, química, mineralógica e metalúrgica dos produtos granulados de minério de ferro. Tese de Doutorado em Engenharia Metalúrgica e de Minas da Escola de Engenharia da UFMG, 299p., 2008. 18. SAMARCO. Disponível em <http://www.samarco.com/uploads/xgccbf.pdf> Acessado em: 08/01/2013. 19. HOLOS, Ano 30, Vol. 3 - Edição Especial - XXV ENTMME / VII MSHNT 7 REFERÊNCIAS BIBLIOGRÁFICAS Dissertação de Mestrado em Engenharia Metalúrgica e de Minas da Escola de Engenharia da UFMG, 80p., 1985. 8. OKANO, A.N. Influência do titânio na microestrutura e propriedades mecânicas de um aço C- Mn microligado com 0,08 a 0,16% de titânio produzindo em tiras laminadas a quente. Dissertação de Mestrado em Engenharia Metalúrgica e de Minas da Escola de Engenharia da UFMG, 80p., 1985. 9. ABONGWA, P.W. Mineral texture and composition of magnetite in the sahavaara IOCG deposit, Pajala área – A mineral processing approach. Master’s thesis presented to the Departmant of Chemincal Engineering and Geosciences of Lulea University of Technology, 9. ABONGWA, P.W. Mineral texture and composition of magnetite in the sahavaara IOCG deposit, Pajala área – A mineral processing approach. Master’s thesis presented to the Departmant of Chemincal Engineering and Geosciences of Lulea University of Technology, HOLOS, Ano 30, Vol. 3 - Edição Especial - XXV ENTMME / VII MSHNT 210 20. STEVENSON, W.J. Estatística aplicada à administração. Harper & Row do Brasil, p.23, 1981. BHP. Disponível em <http://www.google.com.br/url?sa=t&rct=j&q=bhp%20billiton%20pro duct%20specifications_march%202012&source=web&cd=1&cad=rja&ved=0CDQQFjAA&url= http%3A%2F%2Fwww.bhpbilliton.com%2Fhome%2Fbusinesses%2FDocuments%2FBHP%252 0Billiiton%2520Product%2520Specifications%2520June%25202011.pdf&ei=k1rsULLUHtSY1A WjloGgDQ&usg=AFQjCNFcS3-WmfSYIrxwj07hxY_ur72RkA&bvm=bv.1357316858,d.d2k> Acessado em: 08/01/2013. HOLOS, Ano 30, Vol. 3 - Edição Especial - XXV ENTMME / VII MSHNT 211
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Archaeologia Polona
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SPECIAL THEME: THE LORDS OF FLINT – 100TH ANNIVERSARY OF THE DISCOVERY OF THE PREHISTORIC STRIPED FLINT MINES IN KRZEMIONKI The Centenary of the Discovery of the Prehistoric Striped Flint Mines in Krzemionki Andrzej Przychodni and Artur Jedynak  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Krzemionki in the Literature Published in the Years 1923–1939 Magdalena Malak  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Non-invasive Investigation of Segment C of the Krzemionki Exploitation Field. Initial Research Results Artur Jedynak and Piotr Wroniecki  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Re-working the Past: Evidence for Late Neolithic and Early Bronze Age Flint Extraction at the Early Neolithic Mines of Sussex Jon Bączkowski  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 At the Turn: Flint Mining as an Element of Social Changes in the Second Half of the Fifth Millennium BC in Western Lesser Poland Elżbieta Trela-Kieferling and Damian Stefański  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 Workshop Places at Chessy (Seine-et-Marne Dpt., France): Contextual and Technological Aspects Anne Hauzeur, Gilles Monin, Harold Lethrosne, Paul Fernandes and Vincent Delvigne  . . . . . . . . . . SPECIAL THEME: THE LORDS OF FLINT – 100TH ANNIVERSARY OF THE DISCOVERY OF THE PREHISTORIC STRIPED FLINT MINES IN KRZEMIONKI 109 The Flint Quarry of Pozarrate (Treviño, Spain) in the Context of Iberian and Early European Neolithic Mining Antonio Tarriño, Irantzu Elorrietab, Diego Alonso-Herrero, Cristina López-Tascón, Hugo Hernández-Hernández, Nuria Castañeda, David Larreina, Mikel Aguirre and José Antonio Mujika  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127 Mapping Natural Exposures of Siliceous Marls and Cherts as Potential Zones of Raw Material Acquisition. The Case of the Eastern Polish Carpathian Foothills and the Rzeszów Settlement Region (SE Poland) in the Neolithic and Bronze Age. Preliminary Results Andrzej Pelisiak  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 Striped Flint in Archaeological Materials Around the Outcrops of the Kraków-Częstochowa Striped Flint Variety Magdalena Sudoł-Procyk, Magdalena Malak, Hubert Binnebesel and Maciej T. Krajcarz  . . . . . . . . 163 Prehistoric Stone Raw Materials from the Bükk Mountains in Northeastern Hungary Norbert Faragó, Réka Katalin Péter, Orsolya Viktorik, László Máté and Zsolt Mester  . . . . . . . . . . . . 187 Online access to previous volumes of Archaeologia Polona is available at the address: https://journals.iaepan.pl/apolona Archaeologia Polona is regularly indexed in the International Bibliography of the Social Sciences; in IBZ – International Bibliography of Periodical Literature; IBZ – CD-ROM; IBR – International Bibliography of Book Reviews of Scholarly Literature; IBR – CD-ROM. Archaeologia Polona is included within the database of the Anthropological Index Online of the Royal Anthropological Institute of Great Britain and Ireland (http://www.aio.anthropology.org.uk). BOOK REVIEWS Wojciech Brzeziński (ed.), Kopalnie krzemienia na stanowisku „Za garncarzami” w Oża­rowie [Flint mines at the “Za garncarzami” site in Ożarów], Warsaw 2020 Hubert Binnebesel  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231 Elżbieta Trela-Kieferling (ed.), Nakopalniane pracownie krzemieniarskie z okresu neolitu w Bęble, stan. 4, woj. małopolskie [Neolithic Flint Workshops at the Mine in Bębło, Site 4, Małopolska]. Kraków 2021 Dagmara H. Werra  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
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NFAT5-mediated expression of S100A4 contributes to proliferation and migration of renal carcinoma cells
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Christoph Küper 1*, Franz-Xaver Beck 1 and Wolfgang Neuhofer 2 Christoph Küper 1*, Franz-Xaver Beck 1 and Wolfgang Neuhofer 2 Christoph Küper 1*, Franz-Xaver Beck 1 and Wolfgang Neuhofer 2 1 Department of Physiology, University of Munich, Munich, Germany 2 Department of Internal Medicine, Medical Faculty of Mannheim, Medical Clinic V, University of Heidelberg, Mannheim, Germany 1 Department of Physiology, University of Munich, Munich, Germany 2 Department of Internal Medicine, Medical Faculty of Mannheim, Medical Clinic V, University of Heidelberg, Mannheim, Germany The osmosensitive transcription factor nuclear factor of activated T-cells (NFAT) 5, also known as tonicity enhancer binding protein (TonEBP), has been associated with the development of a variety of tumor entities, among them breast cancer, colon carcinoma, and melanoma. The aim of the present study was to determine whether NFAT5 is also involved in the development of renal cell carcinoma (RCC). The most common type of RCC, the clear cell RCC, originates from the proximal convoluted tubule. We tested our hypothesis in the clear cell RCC cell line CaKi-1 and the non-cancerous proximal tubule cell line HK-2, as control. Basal expression of NFAT5 and NFAT5 activity in CaKi-1 cells was several times higher than in HK-2 cells. Osmotic stress induced an increased NFAT5 activity in both CaKi-1 and HK-2 cells, again with significantly higher activities in CaKi-1 cells. Analysis of NFAT5-regulating signaling pathways in CaKi-1 cells revealed that inhibition of the MAP kinases p38, c-Jun-terminal kinase (JNK) and extracellular regulated kinase (ERK) and of the focal adhesion kinase (FAK) partially blunted NFAT5 activity. FAK and ERK were both constitutively active, even under isotonic conditions, which may contribute to the high basal expression and activity of NFAT5 in CaKi-1 cells. In contrast, the MAP kinases p38 and JNK were inactive under isotonic conditions and became activated under osmotic stress conditions, indicating that p38 and JNK mediate upregulation of NFAT5 activity under these conditions. siRNA-mediated knockdown of NFAT5 in CaKi-1 cells reduced the expression of S100A4, a member of the S100 family of proteins, which promotes metastasis. Knockdown of NFAT5 was accompanied by a significant decrease in proliferation and migration activity. Taken together, our results indicate that NFAT5 induces S100A4 expression in CaKi-1 cells, thereby playing an important role in RCC proliferation and migration. Edited by: Edited by: Hyug Moo Kwon, Ulsan National Institute of Science and Technology, South Korea Edited by: Hyug Moo Kwon, Ulsan National Institute of Science and Technology, South Korea Reviewed by: Sang Do Lee, Chungnam National University School of Medicine, South Korea Soo Youn Choi, Ulsan National Institute of Science and Technology, South Korea *Correspondence: Christoph Küper, Department of Physiology, University of Munich, Pettenkoferstrasse 12, 80336 Munich, Germany e-mail: christoph.kueper@ lrz.uni-muenchen.de *Correspondence: Christoph Küper, Department of Physiology, University of Munich, Pettenkoferstrasse 12, 80336 Munich, Germany e-mail: christoph.kueper@ lrz.uni-muenchen.de ORIGINAL RESEARCH ARTICL published: 08 August 201 doi: 10.3389/fphys.2014.0029 NFAT5-mediated expression of S100A4 contributes to proliferation and migration of renal carcinoma cells ORIGINAL RESEARCH ARTICLE bli h d 08 A t 2014 ORIGINAL RESEARCH ARTICLE bli h d 08 A t 2014 published: 08 August 2014 doi: 10.3389/fphys.2014.00293 Keywords: NFAT5, S100A4, renal cell carcinoma, CaKi-1, cell proliferation, cell migration www.frontiersin.org INTRODUCTION involved signaling pathways have been approved in recent years (Motzer, 2011). Although these agents increase the therapeutic options in the treatment of metastatic RCC, continuous research is necessary to gain a better insight to the biological basis of car- cinogenesis and metastasis of renal tubular cells and to identify potential targets for new therapeutic strategies. Renal cell carcinoma (RCC) was the sixth and eighth most com- mon malignancy among men and women, respectively, in 2012, contributing to almost 14,000 deaths in the US (Siegel et al., 2012). The most common type of RCC, the clear cell RCC orig- inates from the proximal convoluted tubule. Metastatic RCC in particular has a very poor prognosis due to the high resistance of the tumors to conventional radiation-, immune-, and chemother- apies. To develop new therapeutic strategies, significant efforts have been made in the last two decades to identify the genetic basis of clear cell RCC. In most cases of sporadic RCC, deletion or mutation of the tumor suppressor gene Von-Hippel-Lindau (VHL) can be detected (Linehan et al., 2003). Under normoxic conditions, VHL catalyzes ubiquitination and, hence, degradation of the transcription factor hypoxia-inducible factor α (HIF-α). Loss of VHL results in accumulation of HIF-α even under nor- moxic conditions and downstream induction of diverse growth and angiogenic factors that contribute to malignant transforma- tion of tubular epithelial cells (Patel et al., 2006). Based on these observations, several new pharmaceutical agents that target the The aim of the present study was to determine whether the osmosensitive transcription factor nuclear factor of activated T- cells (NFAT) 5, also known as tonicity enhancer binding protein (TonEBP), is involved in the development of RCC. The NFAT protein family consists of five members (NFAT1-5) that con- tain a DNA-binding domain with structural similarity to the Rel-homology-region of NF-κB (Muller and Rao, 2010). While activity of NFAT1-4 is regulated by calcineurin, NFAT5 activity is modulated under hyperosmotic conditions at various lev- els: increased expression, increased transcriptional activity, and increased nuclear localization. Upon activation, NFAT5 binds to tonicity enhancer (TonE) elements in the regulatory region of target genes to stimulate transcription (Cheung and Ko, 2013). NFAT5 was discovered originally in the renal medulla, where it August 2014 | Volume 5 | Article 293 | 1 www.frontiersin.org www.frontiersin.org NFAT5 and renal cell carcinoma Küper et al. METHODS MATERIALS Pharmacological inhibitors SB202190, SP600125, U0126, SrcI- 1, and PF-228 were obtained from Sigma (Deisenhofen, Germany). Anti-NFAT5 antibody, anti-Src antibody, anti-FAK antibody, and anti-phospho-FAK antibody were from Santa Cruz Biotechnology (Santa Cruz, CA, USA); anti-actin antibody was from Sigma; anti-p38, anti-phospho-p38, anti-ERK1/2, anti- phospho-ERK1/2, anti-JNK, anti-phospho-JNK, and horseradish peroxidase-conjugated anti-rabbit IgG were purchased from Cell Signaling (Beverly, MA, USA); anti-phospho–Src antibody was from Abgent (Suzhou, China); anti-S100A4 antibody was from Spring Bioscience (Pleasanton, CA, USA). Accell SMARTpool siRNA constructs for knockdown of NFAT5 or S100A4, and qRT-PCR ANALYSIS d For determination of NFAT5, S100A4, AR, and β-Actin mRNA expression levels, the total RNA from HK-2 or CaKi-1 cells was prepared by adding TRIFAST Reagent (Peqlab, Erlangen, Germany). The primers (Metabion, Martinsried, Germany) used in this experiment are: NFAT5_fw: 5′- AAT CGC CCA AGT CCC TCT AC -3′; NFAT5_rev: 5′- GGT GGT AAA GGA GCT GCA AG -3′; Actin_fw: 5′- CCA ACC GCG AGA AGA TGA -3′; Actin_rev: 5′- CCA GAG GCG TAC AGG GAT AG -3′; S100A4_fw: 5′-CGC TTC TTC TTT CTT GGT TTG-3′; S100A4_rev: 5′-GAG TAC TTG TGG AAG GTG GAC A-3′; AR_fw: 5′ATC CGA GCC AAG CAC AAT AA -3′; AR_rev: 5′-AGC AAT GCG TTC TGG TGT CA -3′ Experiments were caried out on a Roche LightCycler 480 using the SensiMix SYBR One-Step Kit (Bioline, Luckenwalde, Germany) according to the manufacturer’s recommendations. Specificity of PCR product formation was confirmed by melting point analysis and by agarose gel electrophoresis. In the present study, we provide evidence that NFAT5 and S100A4 are expressed abundantly in RCC cells, proba- bly due to the constitutive activation of the extracellular reg- ulated kinase (ERK). Under hyperosmotic conditions, NFAT5 is upregulated and, in turn, induces enhanced expression of S100A4. Knockdown of NFAT5 blunts S100A4 expression and also decreased proliferation and migration activity of the cells. CELL CULTURE Immortalized human proximal tubule cells HK-2 (ATCC CRL-2190) and clear cell renal carcinoma cells CaKi-1 (ATCC HTB-46) were cultured in RPMI 1640 supplemented with 10% fetal bovine serum (FBS; Biochrom, Berlin, Germany), 100 units/ml penicillin, and 100 μg/ml streptomycin (Invitrogen, Karlsruhe, Germany). Cells were grown at 37◦C in a humidified atmosphere (95% air/5% CO2). For experiments involving pharmacological inhibitors, cells were preincubated for 30 min with the appropriate inhibitor; medium osmolality was increased by addition of NaCl. p Various reports have also suggested involvement of NFAT5 in the pathogenesis of various tumor entities, such as non-small cell lung cancer (Zhong et al., 2004; Mijatovic et al., 2006), melanoma (Levy et al., 2010), leiomyoma (McCarthy-Keith et al., 2011), breast cancer (Jauliac et al., 2002; Chen et al., 2009; Germann et al., 2012), or colon carcinoma (Chen et al., 2011; Slattery et al., 2011; Alvarez-Diaz et al., 2012). In colon and breast car- cinoma cells NFAT5 drives the expression of the pro-metastatic factor S100A4, also known as metastasin (Chen et al., 2009, 2011). S100A4 belongs to the family of S100 proteins that consists of at least 21 calcium-binding, low-molecular-weight (10–12 kDa) proteins with no known enzymatic activity. S100 proteins form homo- or heterodimers that bind to various target proteins, thereby modulating their activities. Many studies indicated a pathophysiological role for S100A4 in the development of can- cer by promoting proliferation, angiogenesis, cell motility and invasiveness (Garrett et al., 2006). S100A4 binds to several target proteins, among them the tumor suppressor p53 and the non- muscle myosin IIa. Recent studies suggest that S100A4 also plays a role in the development of RCC and may be useful as prognostic marker (Bandiera et al., 2009; Lopez-Lago et al., 2010; Wang et al., 2012; Yang et al., 2012). INTRODUCTION drives the expression of osmoprotective genes such as betaine- GABA-transporter-1 (BGT-1) (Miyakawa et al., 1998), aldose reductase (AR) (Miyakawa et al., 1999), sodium-myo-inositol transporter (Smit) (Miyakawa et al., 1999), taurine transporter (TauT) (Zhang et al., 2003) or heat shock protein (HSP) 70 (Woo et al., 2002), as well as genes that are part of the urinary con- centrating mechanism, such as aquaporin-2 (AQP-2) and urea transporter-A (UT-A) (Han et al., 2004). Besides this function in the kidney, NFAT5 also plays important roles in other cells and tissues, partly in a tonicity-independent manner, during embry- onic development, cell differentiation, inflammatory processes, and cellular stress response (Halterman et al., 2012). Accell non-targeting siRNA (#2) were obtained from Thermo Fisher Scientific (Epsom, UK). Unless otherwise indicated, other reagents were purchased from Biomol (Hamburg, Germany), Biozol (Eching, Germany), Carl Roth (Karlsruhe, Germany), or Sigma. IMMUNOBLOT ANALYSIS Aliquots (10–30 μg protein) were subjected to sodium dode- cylsulphate polyacrylamide gelelectrophoresis (SDS-PAGE) and blotted onto nitrocellulose membranes (Amersham Pharmacia Biotech, Buckinghamshire, UK). Non-specific binding sites were blocked with 5% non-fat dry milk in PBS containing 0.1% Tween-20 (PBS-T) at room temperature for 1 h. Samples were incubated with primary antibodies in PBS-T containing 5% non-fat dry milk over night at 4◦C. Subsequently, the blots were washed 3 times with PBS-T for 5 min each and the membranes then incubated with appropriate secondary antibody at room temperature for 1 h in PBS-T containing 5% non-fat dry milk. After washing with PBS-T 3 times for 5 min each, immunocom- plexes were visualized by enhanced chemiluminescence (Pierce, Rockford, IL, USA). NFAT5 AND NFAT5 TARGET GENES ARE EXPRESSED ABUNDANTLY IN RENAL CARCINOMA CELLS The cell line CaKi-1 was used as model for metastatic clear cell RCC. As non-cancerous control cells, the proximal tubule cell line HK-2 was used. Expression of NFAT5 in CaKi-1 and HK-2 cells was determined at both the mRNA (Figure 1A) and pro- tein (Figure 1B) levels. NFAT5 levels were significantly higher in CaKi-1 cells compared to HK-2 cells. In both cell lines, NFAT5 expression increased during hyperosmotic stress (Figures 1A,B), whilst again expression levels were significantly higher in CaKi- 1 cells. Expression of S100A4 was almost completely absent in HK-2 cells, while substantial amounts were present in CaKi-1 cells. Under hyperosmotic stress conditions, S100A4 expression in CaKi-1 cells increased further. As control, we also evalu- ated expression levels of the well-defined NFAT5 target gene AR. In accordance with the results above, expression levels of AR were also enhanced in CaKi-1 cells, presumably due to increased NFAT5 activity. Cellular activity of NFAT5 in CaKi- 1 and HK-2 cells was assayed using a TonE-driven reporter vector. Cells, transiently transfected with the reporter con- struct, were incubated for 24 h in iso- or hyperosmotic medium. Basal NFAT5 activities under isoosmotic conditions were sig- nificantly higher in CaKi-1 cells (Figure 1C). Under hyperos- motic conditions, NFAT5 activity increased approximately 10 times in both cell types, and hence was significantly higher in CaKi-1 cells, which is in accordance with the higher expres- sion levels of the NFAT5 target genes S100A4 and AR in these cells. REPORTER GENE ASSAYS Activation of NFAT5 in response to hyperosmolality was assessed using the secreted alkaline phosphatase system (SEAP), with August 2014 | Volume 5 | Article 293 | 2 Frontiers in Physiology | Integrative Physiology NFAT5 and renal cell carcinoma Küper et al. a reporter construct, in which the SEAP open reading frame is under control of two TonE sites (Neuhofer et al., 2007). As transfection control, the vector pcDNA3-lacZ, expressing β- galactosidase under the control of the constitutive active CMV promoter, was co-transfected. For transfection, CaKi-1 or HK- 2 cells were grown to ∼80% confluency, trypsinated, washed in PBS and ∼106 cells were finally resuspended in 200 μl modified HBS electroporation buffer (0.5% HEPES, 1% glu- cose, 0.5% Ficoll, 5 mM NaCl, 135 mM KCl, 2 mM MgCl2, pH 7.4) together with 10 μg reporter vector. Electroporation was carried out with a Gene Pulser Xcell Electroporation System (Biorad, Hercules, CA, USA) at 140 V and 1000 μF (exponential decay pulse) in a 2-mm cuvette and the cells seeded immediately thereafter in 96-well plates. After growing to confluency, the cells were treated as indicated and SEAP activity in the medium determined as described in detail else- where (Neuhofer et al., 2007). SEAP activity was normalized to β-galactosidase activity to adjust for uneven transfection of cells. confluency. Subsequently, Accell delivery medium was replaced by RPMI 1640 medium + 10% FCS and the cell momolayer was “scratched” with a 10 μl pipette tip. Cell migration to close the scratch was monitored by capturing images in regular intervals. KNOCKDOWN OF NFAT5 AND S100A4 CaKi-1 cells were grown to ∼80% confluency, trypsinated, washed in PBS and finally resuspended in 100 μl modified HBS electroporation buffer (see above) containing 2 μM of NFAT5 siRNA, S100A4 siRNA or unspecific Accell non-targeting siRNA (#2), as control. Electroporation was carried out as described above. Cells were incubated for 5 days, and knock- down efficiency was determined by qRT-PCR or by Western blot analysis. PROLIFERATION AND SURVIVAL ASSAY For proliferation assays, CaKi-1 cells were transfected with NFAT5-specific, S100A4-specific, or unspecific (control)-siRNA constructs by electroporation as described above. After the elec- tric pulse, cells were seeded immediately in 96-well plates at a den- sity of ∼104 cells/well. After 4 days, viable cells were determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bro- mide (MTT) assay. For this purpose, cells were incubated with MTT (final concentration 0.5 mg/ml in growth medium) for 2 h at 37◦C. Thereafter, growth medium was removed and for- mazan crystals were solubilized in 200 μl acidified isopropanol and absorption was rmeasured at 570 nm. For cell survival assays, cells were treated as described above, but after 4 days the medium osmolality was raised to 600 mosmol/kg H2O by addition of NaCl, and cells were incubated for an additional 24 h. Thereafter, viable cells were determined by MTT assay as described. KNOCKDOWN OF NFAT5 BLUNTS S100A4 EXPRESSION IN CaKi-1 CELLS To confirm that NFAT5 regulates the expression of S100A4 in CaKi-1 cells, we knocked down NFAT5 in CaKi-1 cells. Transfection of the cells with a NFAT5-specific siRNA construct resulted in an approximately 80% reduction of NFAT5 expres- sion compared with cells transfected with an unspecific control siRNA (Figure 2). NFAT5 knockdown was accompanied by sig- nificantly reduced S100A4 expression, both under isosmotic and hyperosmotic conditions (Figure 2). Accordingly, the expression of the designated NFAT5 target gene AR was also significantly decreased in NFAT5-knockdown cells. We also performed siRNA- mediated knockdown of S100A4; as expected, this maneuver had no significant effect on expression of NFAT5 or AR. These results suggest strongly that S100A4 expression in CaKi-1 cells is under the control of NFAT5. STATISTICAL ANALYSES Data are expressed as means ± s.e.m. The significance of differ- ences between the means was assessed by Student’s t-test. P < 0.05 was regarded as significant. All experiments were performed at least 3 times and representative results are shown. SCRATCH ASSAY (B) Cells were incubated for 24 h and subsequently processed for immunoblotting to determine expression of NFAT5, S100A4, and AR as described in Methods. To demonstrate comparable protein loading, the blots were also probed for β-actin. Representative blots from 4 independent experiments are shown. (C) Cells were transfected transiently with a reporter construct in which the SEAP gene is under control of two TonE sites. After 24 h incubation in iso- or hyperosmotic medium, SEAP activity was measured as described in Methods. Data are means ± s.e.m. for n = 4 per point; #P < 0.05 vs. HK-2 isoosmotic medium; ∗P < 0.05 vs. HK-2 hyperosmotic medium. FIGURE 1 | Expression of NFAT5 and NFAT5 target genes in CaKi-1 and HK-2 cells. CaKi-1 cells, as model for clear cell renal cell carcinoma, or HK-2 cells, as proximal tubular control cells, were kept in isoosmotic medium (■; p p 300 mosm/kg H2O) or were exposed to hyperosmotic medium (■; 500 mosm/kg H2O). Medium osmolality was elevated by addition of NaCl. (A) Cells were incubated for 6 h (for determination of NFAT5 transcription) or 16 h (for determination of S100A4 and AR transcription). Thereafter, RNA was extracted and the abundance of NFAT5, S100A4, AR, and β-actin mRNA transcripts determined by qRT-PCR as described in Methods. Relative mRNA abundance of NFAT5, S100A4, or AR was normalized to that of β-actin to correct for differences in RNA input. Data are means ± s.e.m. for n = 4 per p p 300 mosm/kg H2O) or were exposed to hyperosmotic medium (■; 500 mosm/kg H2O). Medium osmolality was elevated by addition of NaCl. (A) Cells were incubated for 6 h (for determination of NFAT5 transcription) or 16 h (for determination of S100A4 and AR transcription). Thereafter, RNA was extracted and the abundance of NFAT5, S100A4, AR, and β-actin mRNA transcripts determined by qRT-PCR as described in Methods. Relative mRNA abundance of NFAT5, S100A4, or AR was normalized to that of β-actin to correct for differences in RNA input. Data are means ± s.e.m. for n = 4 per SCRATCH ASSAY To demonstrate comparable protein loading, the blots were also probed for β-actin. Representative blots from 4 independent experiments are shown. (C) Cells were transfected transiently with a reporter construct in which the SEAP gene is under control of two TonE sites. After 24 h incubation in iso- or hyperosmotic medium, SEAP activity was measured as described in Methods. Data are means ± s.e.m. for n = 4 per point; #P < 0.05 vs. HK-2 isoosmotic medium; ∗P < 0.05 vs. HK-2 hyperosmotic medium. FIGURE 1 | Expression of NFAT5 and NFAT5 target genes in CaKi-1 and HK-2 cells. CaKi-1 cells, as model for clear cell renal cell carcinoma, or HK-2 cells, as proximal tubular control cells, were kept in isoosmotic medium (■; 300 mosm/kg H2O) or were exposed to hyperosmotic medium (■; 500 mosm/kg H2O). Medium osmolality was elevated by addition of NaCl. (A) Cells were incubated for 6 h (for determination of NFAT5 transcription) or 16 h (for determination of S100A4 and AR transcription). Thereafter, RNA was extracted and the abundance of NFAT5, S100A4, AR, and β-actin mRNA transcripts determined by qRT-PCR as described in Methods. Relative mRNA abundance of NFAT5, S100A4, or AR was normalized to that of β-actin to correct for differences in RNA input. Data are means ± s.e.m. for n = 4 per FIGURE 1 | Expression of NFAT5 and NFAT5 target genes in CaKi-1 and HK-2 cells. CaKi-1 cells, as model for clear cell renal cell carcinoma, or HK-2 ll i l b l l ll k i i i di (■ point; #P < 0.05 vs. HK-2 isoosmotic medium; ∗P < 0.05 vs. HK-2 hyperosmotic medium. (B) Cells were incubated for 24 h and subsequently processed for immunoblotting to determine expression of NFAT5, S100A4, and AR as described in Methods. To demonstrate comparable protein loading, the blots were also probed for β-actin. Representative blots from 4 independent experiments are shown. (C) Cells were transfected transiently with a reporter construct in which the SEAP gene is under control of two TonE sites. After 24 h incubation in iso- or hyperosmotic medium, SEAP activity was measured as described in Methods. Data are means ± s.e.m. for n = 4 per point; #P < 0.05 vs. HK-2 isoosmotic medium; ∗P < 0.05 vs. HK-2 hyperosmotic medium. point; #P < 0.05 vs. HK-2 isoosmotic medium; ∗P < 0.05 vs. HK-2 hyperosmotic medium. KNOCKDOWN OF NFAT5 AND S100A4 DECREASES PROLIFERATION AND MIGRATION OF CaKi-1 CELLS were exposed to hyperosmotic conditions (600 mosm/kg H2O) for 24 h and cell survival determined by MTT assay. Compared with control cells incubated under isosmotic conditions, ∼80% of CaKi-1 cells transfected with a control or S100A4-siRNA con- struct survived hyperosmotic stress conditions (Figure 3C), while only ∼65% of NFAT5-knockdown cells survived under these conditions. S100A4 is known to stimulate proliferation and metastasis in renal carcinoma cells (Yang et al., 2013). In the knockdown exper- iments described above, we noticed decelerated growth of CaKi-1 cells transfected with NFAT5- or S100A4-specific siRNA, presum- ably due to downregulation of S100A4. To quantify this effect, we transfected CaKi-1 cells with NFAT5-specific siRNA, S100A4- specific siRNA or unspecific control siRNA, let the cells grow for 96 h in a 96-well plate and determined the number of viable cells by MTT assay. As shown in Figure 3A, NFAT5 siRNA and S100A4 siRNA had significant inhibitory effects on CaKi-1 cell proliferation. These results clearly indicate that both NFAT5 and S100A4 are important for proliferation and migration ability of CaKi-1 cells. NFAT5 is also important for survival during hyperosmotic stress, while S100A4 is probably not essential under these conditions. Frontiers in Physiology | Integrative Physiology SCRATCH ASSAY Cell migration was analyzed using the in vitro scratch assay (Liang et al., 2007), also known as the wound healing assay. CaKi-1 cells at ∼80% confluency were treated for 5 days with Accell SMARTpool NFAT5 siRNA, Accell SMARTpool S100A4 siRNA, or unspecific Accell non-targeting siRNA (#2), as control, with a final concentration of 1000 nM in Accell delivery medium, con- taining 2% FCS, in accordance with the manufacturer’s recom- mendations. During the 5-days incubation period, cells reached August 2014 | Volume 5 | Article 293 | 3 www.frontiersin.org www.frontiersin.org NFAT5 and renal cell carcinoma Küper et al. FIGURE 1 | Expression of NFAT5 and NFAT5 target genes in CaKi-1 and HK-2 cells. CaKi-1 cells, as model for clear cell renal cell carcinoma, or HK-2 cells, as proximal tubular control cells, were kept in isoosmotic medium (■; 300 mosm/kg H2O) or were exposed to hyperosmotic medium (■; 500 mosm/kg H2O). Medium osmolality was elevated by addition of NaCl. (A) Cells were incubated for 6 h (for determination of NFAT5 transcription) or 16 h (for determination of S100A4 and AR transcription). Thereafter, RNA was extracted and the abundance of NFAT5, S100A4, AR, and β-actin mRNA transcripts determined by qRT-PCR as described in Methods. Relative mRNA abundance of NFAT5, S100A4, or AR was normalized to that of β-actin to correct for differences in RNA input. Data are means ± s.e.m. for n = 4 per point; #P < 0.05 vs. HK-2 isoosmotic medium; ∗P < 0.05 vs. HK-2 hyperosmotic medium. (B) Cells were incubated for 24 h and subsequently processed for immunoblotting to determine expression of NFAT5, S100A4, and AR as described in Methods. To demonstrate comparable protein loading, the blots were also probed for β-actin. Representative blots from 4 independent experiments are shown. (C) Cells were transfected transiently with a reporter construct in which the SEAP gene is under control of two TonE sites. After 24 h incubation in iso- or hyperosmotic medium, SEAP activity was measured as described in Methods. Data are means ± s.e.m. for n = 4 per point; #P < 0.05 vs. HK-2 isoosmotic medium; ∗P < 0.05 vs. HK-2 hyperosmotic medium. point; #P < 0.05 vs. HK-2 isoosmotic medium; ∗P < 0.05 vs. HK-2 hyperosmotic medium. (B) Cells were incubated for 24 h and subsequently processed for immunoblotting to determine expression of NFAT5, S100A4, and AR as described in Methods. SIGNAL TRANSDUCTION PATHWAYS INVOLVED IN NFAT5 REGULATION CaKi-1 cells were transfected with siRNA constructs for NFAT5 (siNFAT5), S100A4 (siS100A4) or with non-targeting siRNA (siControl) as indicated. Cells were kept in isoosmotic medium (■; 300 mosm/kg H2O) or were exposed to hyperosmotic medium (■; 500 mosm/kg H2O). Medium osmolality was elevated by addition of NaCl. (A) Cells were incubated for 6 h (for NFAT5 determination) or 16 h (for S100A4 and AR determination). Thereafter, RNA was extracted and the abundance of NFAT5, S100A4, AR, and β-actin mRNA transcripts determined by qRT-PCR as described in Methods. Relative mRNA abundance of NFAT5, S100A4, or AR was normalized to that of β-actin to correct for differences in RNA input. Data are means ± s.e.m. for n = 4 per point; #P < 0.05 vs. siControl isoosmotic medium; ∗P < 0.05 vs. siControl hyperosmotic medium. (B) Cells were incubated for 24 h and subsequently processed for immunoblotting to determine expression of NFAT5, S100A4, and AR as described in Methods. To demonstrate comparable protein loading, the blots were also probed for β-actin. Representative blot from 4 independent experiments is shown. FIGURE 2 | NFAT5-knockdown attenuates S100A4 expression in CaKi-1 cells. CaKi-1 cells were transfected with siRNA constructs for NFAT5 (siNFAT5), S100A4 (siS100A4) or with non-targeting siRNA (siControl) as indicated. Cells were kept in isoosmotic medium (■; 300 mosm/kg H2O) or were exposed to hyperosmotic medium (■; 500 mosm/kg H2O). Medium osmolality was elevated by addition of NaCl. (A) Cells were incubated for 6 h (for NFAT5 determination) or 16 h (for S100A4 and AR determination). Thereafter, RNA was extracted and the abundance of NFAT5, S100A4, AR, and β-actin mRNA transcripts determined by FIGURE 2 | NFAT5-knockdown attenuates S100A4 expression in CaKi-1 cells. CaKi-1 cells were transfected with siRNA constructs for NFAT5 (siNFAT5), S100A4 (siS100A4) or with non-targeting siRNA (siControl) as indicated. Cells were kept in isoosmotic medium (■; 300 mosm/kg H2O) or were exposed to hyperosmotic medium (■; 500 mosm/kg H2O). Medium osmolality was elevated by addition of NaCl. (A) Cells were incubated for 6 h (for NFAT5 determination) or 16 h (for S100A4 and AR determination). Thereafter, RNA was extracted and the abundance of NFAT5, S100A4, AR, and β-actin mRNA transcripts determined by evidence that NFAT5 is also involved in the development and pro- gression of clear cell RCC. We found increased expression and activity of NFAT5 in the RCC cell line CaKi-1 compared with non-cancerous proximal tubule cells. SIGNAL TRANSDUCTION PATHWAYS INVOLVED IN NFAT5 REGULATION Moreover, the metastasis- associated protein S100A4, which has been previously identified in colon cancer cells as an NFAT5 target gene, is very strongly upregulated in CaKi-1 cells. Accordingly, knockdown of NFAT5 also decreased S100A4 expression. In control HK-2 cells, sub- stantial NFAT5 expression and activity can be observed especially during hyperosmotic stress, but S100A4 expression is still almost undetectable under these conditions. This indicates that, in addi- tion to regulation by NFAT5 activity, one or more further mecha- nisms control S100A4 expression. The most probable mechanism is methylation of the S100A4 promoter in normal cells, which effi- ciently prevents S100A4 expression, while the promoter is often hypomethylated in cancer cells, as has been observed in colon cancer cells (Chen et al., 2011). Accordingly, hypomethylation of the S100A4 promoter has also been reported in RCC cells (Lopez-Lago et al., 2010). kinases decreased NFAT5 activity and expression in CaKi-1 cells (Figure 5). However, FAK and Src kinase are also constitutively active in HK-2 cells (Figure 4), indicating that FAK and Src are necessary, but alone not sufficient to account for the high NFAT5 activity in CaKi-1 cells. The MAP kinases p38, ERK1/2 (p44/42), and c-jun-terminal kinase (JNK or p54/46) also regulate NFAT5 activity. p38 and JNK are inactive under isosmotic conditions and are activated under hyperosmotic conditions in both CaKi-1 and HK-2 cells. In contrast, ERK1/2 is constitutively active in CaKi- 1 cells, even under isosmotic conditions, but not in HK-2 cells. Inhibition of ERK1/2, but not of p38 or JNK, decreased NFAT5 activity and expression under isosmotic conditions in CaKi-1 cells (Figures 5A,C), while inhibition of p38 and JNK impaired osmolality-induced upregulation of NFAT5 activity and expres- sion (Figures 5B,D). Accordingly, osmolality induced enhance- ment of S100A4 was attenuated by pharmacological inhibition of Src, FAK, ERK1/2, and p38 (Figure 5F). Surprisingly, JNK inhibition attenuated hyperosmolality-induced S100A4 expres- sion only slightly, the reason for this is unclear. Taken together, these results indicate that constitutive activation of FAK and Src is a prerequisite for NFAT5 expression, osmolality-induced activa- tion of p38 and possibly JNK stimulate NFAT5 activation under hyperosmotic conditions, and constitutive activation of ERK1/2 in CaKi-1 cells is probably responsible for the higher basal activity and expression of NFAT5 in these cells compared with HK-2 cells. The role of S100A4 in RCC has not yet been studied in detail. SIGNAL TRANSDUCTION PATHWAYS INVOLVED IN NFAT5 REGULATION However, in the last years three clinical studies provided evidence that high expression of S100A4 in primary tumors correlates with metastasis and poor prognosis in RCC (Bandiera et al., 2009; Wang et al., 2012; Yang et al., 2012). It has been proposed that upregulation of S100A4 mediates epithelial-to-mesenchymal transition, an initial step in the development of metastasis. Accordingly, S100A4 is highly expressed in the metastatic RCC cell line LM2, whilst knockdown decreases metastatic activity (Lopez-Lago et al., 2010). In another study on RCC cells S100A4 SIGNAL TRANSDUCTION PATHWAYS INVOLVED IN NFAT5 REGULATION We next analyzed the activation of signal transduction path- ways to elucidate the molecular basis for the high basal NFAT5 activity in CaKi-1 cells, compared to HK-2 cells. Various signal- ing molecules are believed to mediate NFAT5 activity, among them focal adhesion kinase (FAK) (Neuhofer et al., 2014), the SRC kinase (Chen et al., 2011), often associated with FAK, and the MAP kinases p38, ERK1/2, and JNK (Tsai et al., 2007). We found that FAK and Src kinase are constitutively active in CaKi-1 cells (Figure 4), and pharmacological inhibition of these Next, the effect of NFAT5- and S100A4-knockdown on the migratory capacity of cells was evaluated using the in vitro scratch assay (Liang et al., 2007). For this purpose, a scratch was created in a confluent monolayer and cell migration to close the scratch was observed under the microscope. As can be seen in Figure 3B, knockdown of NFAT5 or S100A4 clearly decreased the migration ability of CaKi-1 cells. Finally, the effect of NFAT5- and S100A4-knockdown on cell survival during osmotic stress was examined. Confluent cells August 2014 | Volume 5 | Article 293 | 4 Frontiers in Physiology | Integrative Physiology NFAT5 and renal cell carcinoma Küper et al. FIGURE 2 | NFAT5-knockdown attenuates S100A4 expression in CaKi-1 cells. CaKi-1 cells were transfected with siRNA constructs for NFAT5 (siNFAT5), S100A4 (siS100A4) or with non-targeting siRNA (siControl) as indicated. Cells were kept in isoosmotic medium (■; 300 mosm/kg H2O) or were exposed to hyperosmotic medium (■; 500 mosm/kg H2O). Medium osmolality was elevated by addition of NaCl. (A) Cells were incubated for 6 h (for NFAT5 determination) or 16 h (for S100A4 and AR determination). Thereafter, RNA was extracted and the abundance of NFAT5, S100A4, AR, and β-actin mRNA transcripts determined by qRT-PCR as described in Methods. Relative mRNA abundance of NFAT5, S100A4, or AR was normalized to that of β-actin to correct for differences in RNA input. Data are means ± s.e.m. for n = 4 per point; #P < 0.05 vs. siControl isoosmotic medium; ∗P < 0.05 vs. siControl hyperosmotic medium. (B) Cells were incubated for 24 h and subsequently processed for immunoblotting to determine expression of NFAT5, S100A4, and AR as described in Methods. To demonstrate comparable protein loading, the blots were also probed for β-actin. Representative blot from 4 independent experiments is shown. FIGURE 2 | NFAT5-knockdown attenuates S100A4 expression in CaKi-1 cells. DISCUSSION Data are means ± s.e.m. for n = 6; ∗P < 0.05 vs. siControl hyperosmotic medium. FIGURE 3 | Effect of NFAT5 and S100A4 knockdown on proliferation, FIGURE 3 | Effect of NFAT5 and S100A4 knockdown on proliferation, migration and survival of CaKi-1 cells. (A) Proliferation. CaKi-1 cells (104 per case) were transfected with NFAT5-specific (siNFAT5), S100A4-specific (siS100A4), or unspecific control (siControl) siRNA constructs as described in Methods and seeded into one well of a 96-well plate. After 96 h, the cell number in each well was determined by MTT assay. The number of viable cells treated with control siRNA was defined as 100%. Data are means ± s.e.m. for n = 6; ∗P < 0.05 vs. siControl. (B) Migration. CaKi-1 cells were treated with NFAT5-specific (siNFAT5), S100A4-specific (siS100A4), or unspecific control (siControl) siRNA constructs as described in Methods. After reaching confluency, the stimulates the expression of Bcl-2, thereby attenuating apoptosis, and MMP-2, which may also stimulate metastatic activity (Yang et al., 2013). conditions. The absence of this osmoadaptive response in NFAT5- knockdown cells is probably the reason for the observed decreased resistance to hyperosmotic conditions in these cells. CaKi-1 cells, as a model for clear cell RCC, originate from the cortical proximal tubule. Since this region is not exposed to hyperosmotic stress, even during antidiuresis, osmolality-induced increase of cellular NFAT5 activity may be not relevant as long as tumor cells remain in the cortex. However, if cells of a growing tumor invade the renal medullary region, these cells are exposed to hyperosmotic condi- tions, which means that NFAT5 activity is increased. On the one hand, this probably facilitates survival of tumor cells by elevating the expression of S100A4 and other osmoadaptive genes like AR, HSP70, or BGT-1; on the other, the elevated S100A4 expression may also increase the metastatic activity of the tumor cells. Interestingly, S100A4 is expressed in the normal (i.e., non- cancerous) kidney under physiological conditions (Rivard et al., 2007). While it is not expressed in the isosmotic renal cortex, S100A4 can be detected in the hyperosmotic renal medulla, where its expression is even more stimulated during antidiuresis. In the same study, the authors showed that S100A4 is strongly induced under hyperosmotic conditions in inner medullary collecting duct cells and that knockdown of S100A4 results in a 48 h-delay in the onset of adaptation to hypertonic stress. DISCUSSION The osmosensitive transcription factor NFAT5 has been associ- ated with a variety of cancers. Here we present for the first time August 2014 | Volume 5 | Article 293 | 5 www.frontiersin.org www.frontiersin.org NFAT5 and renal cell carcinoma Küper et al. FIGURE 3 | Effect of NFAT5 and S100A4 knockdown on proliferation, migration and survival of CaKi-1 cells. (A) Proliferation. CaKi-1 cells (104 per case) were transfected with NFAT5-specific (siNFAT5), S100A4-specific (siS100A4), or unspecific control (siControl) siRNA constructs as described in Methods and seeded into one well of a 96-well plate. After 96 h, the cell number in each well was determined by MTT assay. The number of viable cells treated with control siRNA was defined as 100%. Data are means ± s.e.m. for n = 6; ∗P < 0.05 vs. siControl. (B) Migration. CaKi-1 cells were treated with NFAT5-specific (siNFAT5), S100A4-specific (siS100A4), or unspecific control (siControl) siRNA constructs as described in Methods. After reaching confluency, the cell layer was scratched with a 10 μl pipette tip. Shown are representative phase-contrast images of cells migrating into the wounded area, immediately after scratching (0 h) and after an incubation time of 24 h. (C) Cell survival. CaKi-1 cells were treated with NFAT5-specific (siNFAT5), S100A4-specific (siS100A4), or unspecific control (siControl) siRNA constructs as described in Methods. Confluent cells were kept in isoosmotic medium (■; 300 mosm/kg H2O) or were exposed to hyperosmotic medium (■; 600 mosm/kg H2O) for 24 h. Thereafter, the cell number in each well was determined by MTT assay. Cell numbers in isosmotic controls (■) were defined as 100%. Data are means ± s.e.m. for n = 6; ∗P < 0.05 vs. siControl hyperosmotic medium. FIGURE 3 | Effect of NFAT5 and S100A4 knockdown on proliferation, migration and survival of CaKi-1 cells (A) Proliferation CaKi-1 cells cell layer was scratched with a 10 μl pipette tip. Shown are representative phase-contrast images of cells migrating into the wounded area, immediately after scratching (0 h) and after an incubation time of 24 h. (C) Cell survival. CaKi-1 cells were treated with NFAT5-specific (siNFAT5), S100A4-specific (siS100A4), or unspecific control (siControl) siRNA constructs as described in Methods. Confluent cells were kept in isoosmotic medium (■; 300 mosm/kg H2O) or were exposed to hyperosmotic medium (■; 600 mosm/kg H2O) for 24 h. Thereafter, the cell number in each well was determined by MTT assay. Cell numbers in isosmotic controls (■) were defined as 100%. DISCUSSION Inhibiton of JNK decreased NFAT5 activity, but expression of S100A4 was only slightly and non-significantly decreased. The reason for this discrepancy is not clear. Most reports in the lit- erature deny an involvement of JNK in NFAT5 activation (Kultz et al., 1997; Kojima et al., 2010; Roth et al., 2010). In colon cancer cells NFAT5-mediated upregulation of S100A4 has been shown to be stimulated by Integrins and Src kinase (Chen et al., 2011). Integrins are transmembrane receptors that link the extracellular matrix to the intracellular actin cytoskele- ton. Integrins can also initiate intracellular signaling events by co-clustering with receptor- and non-receptor protein tyrosine kinases (PTK). The non-receptor PTK Src often forms a dual kinase complex with the non-receptor PTK FAK. Activated FAK- Src complex promotes cell cycle progression, cell motility and cell survival and is therefore often associated with the develop- ment of cancer and metastasis (Mitra and Schlaepfer, 2006). It was reported recently that Src and FAK are also expressed and activated in patients with clear cell RCC (Qayyum et al., 2012). Our own studies suggest that FAK is a positive regulator of NFAT5 expression in HEK 293 cells (Neuhofer et al., 2014). Accordingly, the data of the present study provide evidence that NFAT5 expres- sion and activity in CaKi-1 cells is positive regulated by Src and FAK. Pharmacological inhibition of these kinases decreased cellu- lar NFAT5 activity and expression of S100A4, and both kinases are constitutively active in CaKi-1 cells. Since Src and FAK were also constitutively active in HK-2 cells it is doubtful whether patho- physiological upregulation of FAK-Src activity is responsible for the elevated NFAT5 activity in RCC cells. In contrast, the MAP kinase ERK1/2 was constitutively active in CaKi-1 cells, but not in HK-2 cells. The role of ERK in NFAT5 activation is currently controversial and may depend on the cell type (Tsai et al., 2007; Morancho et al., 2008). In the present study, inhibition of ERK in CaKi-1 cells attenuated both NFAT5 activation and expression and also S100A4 expression, indicating that constitutive activa- tion of this kinase is at least partly responsible for the high NFAT5 activity in RCC cells. Constitutive activation of the Ras-Raf- MEK-ERK pathway, which mediates cellular responses to growth signals under physiological conditions, has been observed in a wide variety of cancers (Roberts and Der, 2007), but the molec- ular mechanisms underlying this constitutive activation vary. DISCUSSION These data sug- gest that S100A4 is under physiological conditions part of the osmoadaptive response that allows cells to tolerate the harsh con- ditions in the renal inner medulla, however, in the present study knockdown of S100A4 had no significant effect on CaKi-1 cell survival during hyperosmotic stress. Whether S100A4 expression in medullary collecting duct cells is driven by NFAT5 has not been studied extensively, but the present results and other stud- ies (Chen et al., 2009, 2011) strongly suggest that this is so. In the present study, we also observed an “intact” osmoadaptive response in CaKi-1 cells, meaning that NFAT5 mediates upreg- ulation of osmoadaptive genes such as AR under hyperosmotic We observed also that NFAT5 knockdown decreases prolifera- tion and migration of CaKi-1 cells. This is probably due, at least in part, to the decreased S100A4 expression, since it has been shown before that S100A4 promotes proliferation and migration in renal carcinoma cells (Yang et al., 2013). However, it cannot be ruled out that other NFAT5 target genes also stimulate tumor development and metastasis. Especially the designated NFAT5 target gene HSP70 has been implicated in tumor cell prolifera- tion, differentiation, and metastasis in a wide variety of cancers August 2014 | Volume 5 | Article 293 | 6 Frontiers in Physiology | Integrative Physiology Küper et al. NFAT5 and renal cell carcinoma FIGURE 4 | Activation of signaling molecules in CaKi-1 and HK-2 cells. CaKi-1 cells or HK-2 cells were incubated in isoosmotic medium (300 mosm/kg H2O) or hyperosmotic medium (500 mosm/kg H2O). Medium osmolality was elevated by addition of NaCl. Cells were incubated for 1 h and subsequently lysed and abundance and phosphorylation status of FAK, Src, JNK, ERK1/2, and p38 determined by immunoblotting as described in Methods. Representative blots from 4 independent experiments are shown. FIGURE 4 | Activation of signaling molecules in CaKi-1 and HK-2 cells We investigated osmolality-related signal transduction pro- cesses and observed activation of the MAP kinases p38 and JNK in both CaKi-1 and HK-2 cells in response to hyperosmotic conditions. Our results indicate clearly that p38 is involved in upregulation of NFAT5 activity and expression of the NFAT5 tar- get gene S100A4 in CaKi-1 cells under these conditions, consistent with previous reports (Lee et al., 2008; Roth et al., 2010). The role of JNK for NFAT5 activation in CaKi-1 cells is more uncer- tain. DISCUSSION An important mechanism that has been identified in various tumor entities is mutation of the BRAF gene, which results in expression of a constitutive active B-Raf kinase and hence constitutive acti- vation of ERK (Davies et al., 2002). However, since CaKi-1 cells harbor a wildtype BRAF gene (Friday et al., 2008), this mecha- nism can be excluded. A possible mechanism for constitutive ERK activation in RCC cells is increased expression of transforming growth factor-α (TGF-α), a ligand of the epidermal growth factor receptor (EGFR). We have previously found in (non-cancerous) FIGURE 4 | Activation of signaling molecules in CaKi-1 and HK-2 cells. FIGURE 4 | Activation of signaling molecules in CaKi-1 and HK-2 cells. CaKi-1 cells or HK-2 cells were incubated in isoosmotic medium (300 mosm/kg H2O) or hyperosmotic medium (500 mosm/kg H2O). Medium osmolality was elevated by addition of NaCl. Cells were incubated for 1 h and subsequently lysed and abundance and phosphorylation status of FAK, Src, JNK, ERK1/2, and p38 determined by immunoblotting as described in Methods. Representative blots from 4 independent experiments are shown. CaKi-1 cells or HK-2 cells were incubated in isoosmotic medium (300 mosm/kg H2O) or hyperosmotic medium (500 mosm/kg H2O). Medium osmolality was elevated by addition of NaCl. Cells were incubated for 1 h and subsequently lysed and abundance and phosphorylation status of FAK, Src, JNK, ERK1/2, and p38 determined by immunoblotting as described in Methods. Representative blots from 4 independent experiments are shown. (Ciocca and Calderwood, 2005). In non-small cell lung cancer, NFAT5-mediated upregulation of HSP70 confers enhanced resis- tance against apoptosis on tumor cells by inhibition of lysosomal membrane permeabilization (Zhong et al., 2004; Mijatovic et al., 2006). High expression of HSP70 has also been observed in RCC, however, it is not clear whether HSP70-mediated inhibition of apoptosis plays an important role in carcinogenesis and tumor progression in RCC (Ramp et al., 2007). Other proposed NFAT5 target genes reportedly upregulated in RCC are Cyr61 (O’Connor et al., 2007; Chintalapudi et al., 2008), and COX-2 (Chen et al., 2004; Favale et al., 2009), whether NFAT5 is responsible for this upregulation remains to be established. (Ciocca and Calderwood, 2005). In non-small cell lung cancer, NFAT5-mediated upregulation of HSP70 confers enhanced resis- tance against apoptosis on tumor cells by inhibition of lysosomal membrane permeabilization (Zhong et al., 2004; Mijatovic et al., 2006). DISCUSSION High expression of HSP70 has also been observed in RCC, however, it is not clear whether HSP70-mediated inhibition of apoptosis plays an important role in carcinogenesis and tumor progression in RCC (Ramp et al., 2007). Other proposed NFAT5 target genes reportedly upregulated in RCC are Cyr61 (O’Connor et al., 2007; Chintalapudi et al., 2008), and COX-2 (Chen et al., 2004; Favale et al., 2009), whether NFAT5 is responsible for this upregulation remains to be established. August 2014 | Volume 5 | Article 293 | 7 www.frontiersin.org NFAT5 and renal cell carcinoma Küper et al. FIGURE 5 | Inhibition of FAK, Src, and MAP kinases attenuates NFAT5 activity in CaKi-1 cells. CaKi-1 cells were preincubated with the ERK1/2 inhibitor U0126 (U0; 10 μM), the p38 inhibitor SB202190 (SB; 10 μM), the JNK inhibitor SP600125 (SP; 10 μM), the FAK inhibitor PF-228 (PF; 5 μM), the Src inhibitor SrcI-1 (SrcI; 10 μM), or vehicle DMSO (Veh) for 30 min. Subsequently, cells were incubated at 300 or 500 mosm/kg H2O as indicated. (A,B) CaKi-1 cells were transfected transiently with a reporter construct in which the SEAP gene is under control of two TonE sites. After preincubation, the transfected cells were incubated for 24 h at 300 or 500 mosm/kg H2O, as indicated. Subsequently, SEAP activity was measured as described in Methods. Data are means ± s.e.m. for n = 4 per point; ∗P < 0.05 vs. vehicle; #P < 0.05 vs. vehicle hyperosmotic medium. (C–F) After preincubation, CaKi-1 cells were incubated for 16 h at 300 or 500 mosm/kg H2O, as indicated. Subsequently, RNA was extracted and the abundance of NFAT5, S100A4 and β-actin mRNA transcripts was determined by qRT-PCR as described in Methods. Relative mRNA abundance of NFAT5 and S100A4 was normalized to that of β-actin to correct for differences in RNA input. Data are means ± s.e.m. for n = 4 per point; *P < 0.05 vs. vehicle; #P < 0.05 vs. vehicle hyperosmotic medium. FIGURE 5 | Inhibition of FAK, Src, and MAP kinases attenuates NFAT5 activity in CaKi-1 cells. CaKi-1 cells were preincubated with the ERK1/2 inhibitor U0126 (U0; 10 μM), the p38 inhibitor SB202190 (SB; 10 μM), the JNK inhibitor SP600125 (SP; 10 μM), the FAK inhibitor PF-228 (PF; 5 μM), the Src inhibitor SrcI-1 (SrcI; 10 μM), or vehicle DMSO (Veh) for 30 min. Subsequently, cells were incubated at 300 or 500 mosm/kg H2O as indicated. DISCUSSION (A,B) CaKi-1 cells were transfected transiently with a reporter construct in which the SEAP gene is under control of two TonE sites. After preincubation, the transfected cells were incubated for 24 h at 300 or 500 mosm/kg H2O, as indicated. Subsequently, SEAP activity was measured as described in Methods. Data are means ± s.e.m. for n = 4 per point; ∗P < 0.05 vs. vehicle; #P < 0.05 vs. vehicle hyperosmotic medium. (C–F) After preincubation, CaKi-1 cells were incubated for 16 h at 300 or 500 mosm/kg H2O, as indicated. Subsequently, RNA was extracted and the abundance of NFAT5, S100A4 and β-actin mRNA transcripts was determined by qRT-PCR as described in Methods. Relative mRNA abundance of NFAT5 and S100A4 was normalized to that of β-actin to correct for differences in RNA input. Data are means ± s.e.m. for n = 4 per point; *P < 0.05 vs. vehicle; #P < 0.05 vs. vehicle hyperosmotic medium. FIGURE 5 | Inhibition of FAK, Src, and MAP kinases attenuates NFAT5 ACKNOWLEDGMENTS renal collecting duct cells that maximal NFAT5 activation requires TGF-α-mediated activation of the EGFR and the downstream ERK kinase (Küper et al., 2009). Furthermore, overexpression of TGF-α has long been known as a characteristic feature and has been implicated with proliferation and vascularization of RCC (Gomella et al., 1989; Gunaratnam et al., 2003; Pelletier et al., 2009). We plan to investigate this potential mechanism for ERK activation in RCC cells in future studies. Work in the authors’ laboratory was supported by grants from the Deutsche Forschungsgemeinschaft, the Deutsche Nierenstiftung, the Münchener Medizinische Wochenschrift, and by the Friedrich Baur Stiftung, Munich. We thank Dr. John Davies for critical reading of the manuscript. The help of Maria-Luisa Fraek is gratefully acknowledged. Work in the authors’ laboratory was supported by grants from the Deutsche Forschungsgemeinschaft, the Deutsche Nierenstiftung, the Münchener Medizinische Wochenschrift, and by the Friedrich Baur Stiftung, Munich. We thank Dr. John Davies for critical reading of the manuscript. The help of Maria-Luisa Fraek is gratefully acknowledged. CONCLUSIONS NFAT5 in cellular adaptation to hyper- tonic stress–regulations and functional significance. J. Mol. Signal. 8:5. doi: 10.1186/1750-2187-8-5 Linehan, W. M., Walther, M. M., and Zbar, B. (2003). The genetic basis of cancer of the kidney. J. Urol. 170, 2163–2172. doi: 10.1097/01.ju.0000096060.92397.ed Lopez-Lago, M. A., Thodima, V. J., Guttapalli, A., Chan, T., Heguy, A., Molina, A. M., et al. (2010). Genomic deregulation during metastasis of renal cell carci- noma implements a myofibroblast-like program of gene expression. Cancer Res. 70, 9682–9692. doi: 10.1158/0008-5472.CAN-10-2279 Chintalapudi, M. R., Markiewicz, M., Kose, N., Dammai, V., Champion, K. J., Hoda, R. S., et al. (2008). Cyr61/CCN1 and CTGF/CCN2 mediate the proangio- genic activity of VHL-mutant renal carcinoma cells. Carcinogenesis 29, 696–703. doi: 10.1093/carcin/bgn019 McCarthy-Keith, D. M., Malik, M., Britten, J., Segars, J., and Catherino, W. H. (2011). Gonadotropin-releasing hormone agonist increases expression of osmotic response genes in leiomyoma cells. Fertil. Steril. 95, 2383–2387. doi: 10.1016/j.fertnstert.2011.03.084 Ciocca, D. R., and Calderwood, S. K. (2005). Heat shock proteins in can- cer: diagnostic, prognostic, predictive, and treatment implications. Cell Stress Chaperones 10, 86–103. doi: 10.1379/CSC-99r.1 Davies, H., Bignell, G. R., Cox, C., Stephens, P., Edkins, S., Clegg, S., et al. (2002). Mutations of the BRAF gene in human cancer. Nature 417, 949–954. doi: 10.1038/nature00766 Mijatovic, T., Mathieu, V., Gaussin, J. F., De Neve, N., Ribaucour, F., Van Quaquebeke, E., et al. (2006). Cardenolide-induced lysosomal membrane permeabilization demonstrates therapeutic benefits in experimental human non-small cell lung cancers. Neoplasia 8, 402–412. doi: 10.1593/neo.05850 Favale, N. O., Casali, C. I., Lepera, L. G., Pescio, L. G., and Fernandez-Tome, M. C. (2009). Hypertonic induction of COX2 expression requires TonEBP/NFAT5 in renal epithelial cells. Biochem. Biophys. Res. Commun. 381, 301–305. doi: 10.1016/j.bbrc.2008.12.189 Mitra, S. K., and Schlaepfer, D. D. (2006). Integrin-regulated FAK-Src signal- ing in normal and cancer cells. Curr. Opin. Cell Biol. 18, 516–523. doi: 10.1016/j.ceb.2006.08.011 Miyakawa, H., Woo, S. K., Chen, C. P., Dahl, S. C., Handler, J. S., and Kwon, H. M. (1998). Cis- and trans-acting factors regulating transcription of the BGT1 gene in response to hypertonicity. Am. J. Physiol. 274, F753–F761. Friday, B. B., Yu, C., Dy, G. K., Smith, P. D., Wang, L., Thibodeau, S. N., et al. (2008). BRAF V600E disrupts AZD6244-induced abrogation of negative feedback path- ways between extracellular signal-regulated kinase and Raf proteins. Cancer Res. 68, 6145–6153. doi: 10.1158/0008-5472.CAN-08-1430 Miyakawa, H., Woo, S. K., Dahl, S. C., Handler, J. S., and Kwon, H. M. (1999). CONCLUSIONS Tonicity-responsive enhancer binding protein, a rel-like protein that stimu- lates transcription in response to hypertonicity. Proc. Natl. Acad. Sci. U.S.A. 96, 2538–2542. doi: 10.1073/pnas.96.5.2538 Garrett, S. C., Varney, K. M., Weber, D. J., and Bresnick, A. R. (2006). S100A4, a mediator of metastasis. J. Biol. Chem. 281, 677–680. doi: 10.1074/jbc.R500 017200 Germann, S., Gratadou, L., Zonta, E., Dardenne, E., Gaudineau, B., Fougere, M., et al. (2012). Dual role of the ddx5/ddx17 RNA helicases in the control of the pro-migratory NFAT5 transcription factor. Oncogene 31, 4536–4549. doi: 10.1038/onc.2011.618 Morancho, B., Minguillon, J., Molkentin, J. D., Lopez-Rodriguez, C., and Aramburu, J. (2008). Analysis of the transcriptional activity of endogenous NFAT5 in primary cells using transgenic NFAT-luciferase reporter mice. BMC Mol. Biol. 9:13. doi: 10.1186/1471-2199-9-13 Gomella, L. G., Sargent, E. R., Wade, T. P., Anglard, P., Linehan, W. M., and Kasid, A. (1989). Expression of transforming growth factor alpha in normal human adult kidney and enhanced expression of transforming growth factors alpha and beta 1 in renal cell carcinoma. Cancer Res. 49, 6972–6975. Motzer, R. J. (2011). New perspectives on the treatment of metastatic renal cell carcinoma: an introduction and historical overview. Oncologist 16(Suppl. 2), 1–3. doi: 10.1634/theoncologist.2011-S2-01 Muller, M. R., and Rao, A. (2010). NFAT, immunity and cancer: a transcription factor comes of age. Nat. Rev. Immunol. 10, 645–656. doi: 10.1038/nri2818 Gunaratnam, L., Morley, M., Franovic, A., De Paulsen, N., Mekhail, K., Parolin, D. A., et al. (2003). Hypoxia inducible factor activates the transforming growth factor-alpha/epidermal growth factor receptor growth stimulatory pathway in VHL(-/-) renal cell carcinoma cells. J. Biol. Chem. 278, 44966–44974. doi: 10.1074/jbc.M305502200 Neuhofer, W., Kuper, C., Lichtnekert, J., Holzapfel, K., Rupanagudi, K. V., Fraek, M. L., et al. (2014). Focal adhesion kinase regulates the activity of the osmosen- sitive transcription factor TonEBP/NFAT5 under hypertonic conditions. Front. Physiol. 5:123. doi: 10.3389/fphys.2014.00123 Halterman, J. A., Kwon, H. M., and Wamhoff, B. R. (2012). Tonicity- independent regulation of the osmosensitive transcription factor TonEBP (NFAT5). Am. J. Physiol. Cell Physiol. 302, C1–C8. doi: 10.1152/ajpcell. 00327.2011 Neuhofer, W., Steinert, D., Fraek, M. L., and Beck, F. X. (2007). Prostaglandin E2 stimulates expression of osmoprotective genes in MDCK cells and pro- motes survival under hypertonic conditions. J. Physiol. 583, 287–297. doi: 10.1113/jphysiol.2007.135178 O’Connor, R. S., Mills, S. T., Jones, K. A., Ho, S. N., and Pavlath, G. K. (2007). A combinatorial role for NFAT5 in both myoblast migration and differ- entiation during skeletal muscle myogenesis. CONCLUSIONS Alvarez-Diaz, S., Valle, N., Ferrer-Mayorga, G., Lombardia, L., Herrera, M., Dominguez, O., et al. (2012). MicroRNA-22 is induced by vitamin D and con- tributes to its antiproliferative, antimigratory and gene regulatory effects in colon cancer cells. Hum. Mol. Genet. 21, 2157–2165. doi: 10.1093/hmg/dds031 Taken together, the present study shows that the osmosensitive transcription factor NFAT5 is expressed abundantly and is highly active in the RCC cell line CaKi-1. NFAT5 stimulates the expres- sion of the S100A4 metastasis factor in these cells, thereby regu- lating proliferation and migration activity. These results indicate that NFAT5 may contribute to the development and progression of RCC. Bandiera, A., Melloni, G., Freschi, M., Giovanardi, M., Carretta, A., Borri, A., et al. (2009). Prognostic factors and analysis of S100a4 protein in resected pul- monary metastases from renal cell carcinoma. World J. Surg. 33, 1414–1420. doi: 10.1007/s00268-009-0023-5 Chen, M., Sastry, S. K., and O’Connor, K. L. (2011). Src kinase pathway is involved in NFAT5-mediated S100A4 induction by hyperosmotic stress in colon August 2014 | Volume 5 | Article 293 | 8 Frontiers in Physiology | Integrative Physiology | 8 NFAT5 and renal cell carcinoma Küper et al. cancer cells. Am. J. Physiol. Cell Physiol. 300, C1155–C1163. doi: 10.1152/ajp- cell.00407.2010 Lee, J. H., Kim, M., Im, Y. S., Choi, W., Byeon, S. H., and Lee, H. K. (2008). NFAT5 induction and its role in hyperosmolar stressed human limbal epithelial cells. Invest. Ophthalmol. Vis. Sci. 49, 1827–1835. doi: 10.1167/iovs.07-1142 cancer cells. Am. J. Physiol. Cell Physiol. 300, C1155–C1163. doi: 10.1152/ajp- cell.00407.2010 Chen, M., Sinha, M., Luxon, B. A., Bresnick, A. R., and O’Connor, K. L. (2009). Integrin alpha6beta4 controls the expression of genes associated with cell motil- ity, invasion, and metastasis, including S100A4/metastasin. J. Biol. Chem. 284, 1484–1494. doi: 10.1074/jbc.M803997200 Levy, C., Khaled, M., Iliopoulos, D., Janas, M. M., Schubert, S., Pinner, S., et al. (2010). Intronic miR-211 assumes the tumor suppressive function of its host gene in melanoma. Mol. Cell 40, 841–849. doi: 10.1016/j.molcel.2010.11.020 Chen, Q., Shinohara, N., Abe, T., Watanabe, T., Nonomura, K., and Koyanagi, T. (2004). Significance of COX-2 expression in human renal cell carcinoma cell lines. Int. J. Cancer 108, 825–832. doi: 10.1002/ijc.11646 Liang, C. C., Park, A. Y., and Guan, J. L. (2007). In vitro scratch assay: a convenient and inexpensive method for analysis of cell migration in vitro. Nat. Protoc. 2, 329–333. doi: 10.1038/nprot.2007.30 Cheung, C. Y., and Ko, B. C. (2013). CONCLUSIONS 282, 6644–6652. doi: 10.1074/jbc.M609432200 involved in the renal osmoadaptive response. J. Biol. Chem. 282, 6644–6652. doi: 10.1074/jbc.M609432200 Yang, X. C., Wang, X., Luo, L., Dong, D. H., Yu, Q. C., Wang, X. S., et al. (2013). RNA interference suppression of A100A4 reduces the growth and metastatic phenotype of human renal cancer cells via NF-kB-dependent MMP-2 and bcl-2 pathway. Eur. Rev. Med. Pharmacol. Sci. 17, 1669–1680. Roberts, P. J., and Der, C. J. (2007). Targeting the Raf-MEK-ERK mitogen-activated protein kinase cascade for the treatment of cancer. Oncogene 26, 3291–3310. doi: 10.1038/sj.onc.1210422 Zhang, Z., Ferraris, J. D., Brooks, H. L., Brisc, I., and Burg, M. B. (2003). Expression of osmotic stress-related genes in tissues of normal and hyposmotic rats. Am. J. Physiol. Renal Physiol. 285, F688–F693. doi: 10.1152/ajprenal.00028.2003 Roth, I., Leroy, V., Kwon, H. M., Martin, P. Y., Feraille, E., and Hasler, U. (2010). Osmoprotective transcription factor NFAT5/TonEBP modulates nuclear factor- kappaB activity. Mol. Biol. Cell 21, 3459–3474. doi: 10.1091/mbc.E10-02-0133 Zhong, L., Peng, X., Hidalgo, G. E., Doherty, D. E., Stromberg, A. J., and Hirschowitz, E. A. (2004). Identification of circulating antibodies to tumor- associated proteins for combined use as markers of non-small cell lung cancer. Proteomics 4, 1216–1225. doi: 10.1002/pmic.200200679 Siegel, R., Naishadham, D., and Jemal, A. (2012). Cancer statistics, 2012. CA Cancer J. Clin. 62, 10–29. doi: 10.3322/caac.20138 Slattery, M. L., Lundgreen, A., Bondurant, K. L., and Wolff, R. K. (2011). Tumor necrosis factor-related genes and colon and rectal cancer. Int. J. Mol. Epidemiol. Genet. 2, 328–338. Conflict of Interest Statement: The authors declare that the research was con- ducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Tsai, T. T., Guttapalli, A., Agrawal, A., Albert, T. J., Shapiro, I. M., and Risbud, M. V. (2007). MEK/ERK signaling controls osmoregulation of nucleus pulposus cells of the intervertebral disc by transactivation of TonEBP/OREBP. J. Bone Miner. Res. 22, 965–974. doi: 10.1359/jbmr.070322 Received: 30 December 2013; accepted: 21 July 2014; published online: 08 August 2014. Citation: Küper C, Beck F-X and Neuhofer W (2014) NFAT5-mediated expression of S100A4 contributes to proliferation and migration of renal carcinoma cells. Front. Physiol. 5:293. doi: 10.3389/fphys.2014.00293 This article was submitted to Integrative Physiology, a section of the journal Frontiers Wang, L. J., Matoso, A., Sciandra, K. T., Yakirevich, E., Sabo, E., Zhang, Y., et al. (2012). Expression of S100A4 in renal epithelial neoplasms. Appl. Immunohistochem. CONCLUSIONS J. Cell Sci. 120, 149–159. doi: 10.1242/jcs.03307 Han, K. H., Woo, S. K., Kim, W. Y., Park, S. H., Cha, J. H., Kim, J., et al. (2004). Maturation of TonEBP expression in developing rat kidney. Am. J. Physiol. Renal Physiol. 287, F878–F885. doi: 10.1152/ajprenal.00047.2004 Jauliac, S., Lopez-Rodriguez, C., Shaw, L. M., Brown, L. F., Rao, A., and Toker, A. (2002). The role of NFAT transcription factors in integrin-mediated carcinoma invasion. Nat. Cell Biol. 4, 540–544. doi: 10.1038/ncb816 Patel, P. H., Chadalavada, R. S., Chaganti, R. S., and Motzer, R. J. (2006). Targeting von Hippel-Lindau pathway in renal cell carcinoma. Clin. Cancer Res. 12, 7215–7220. doi: 10.1158/1078-0432.CCR-06-2254 Kojima, R., Taniguchi, H., Tsuzuki, A., Nakamura, K., Sakakura, Y., and Ito, M. (2010). Hypertonicity-induced expression of monocyte chemoattractant protein-1 through a novel cis-acting element and MAPK signaling pathways. J. Immunol. 184, 5253–5262. doi: 10.4049/jimmunol.0901298 Pelletier, S., Tanguay, S., Lee, S., Gunaratnam, L., Arbour, N., and Lapointe, R. (2009). TGF-alpha as a candidate tumor antigen for renal cell carcinomas. Cancer Immunol. Immunother. 58, 1207–1218. doi: 10.1007/s00262-008-0630-2 Kultz, D., Garcia-Perez, A., Ferraris, J. D., and Burg, M. B. (1997). Distinct regula- tion of osmoprotective genes in yeast and mammals. Aldose reductase osmotic response element is induced independent of p38 and stress-activated pro- tein kinase/Jun N-terminal kinase in rabbit kidney cells. J. Biol. Chem. 272, 13165–13170. doi: 10.1074/jbc.272.20.13165 Qayyum, T., McArdle, P. A., Lamb, G. W., Jordan, F., Orange, C., Seywright, M., et al. (2012). Expression and prognostic significance of Src family members in renal clear cell carcinoma. Br. J. Cancer 107, 856–863. doi: 10.1038/bjc.2012.314 Ramp, U., Mahotka, C., Heikaus, S., Shibata, T., Grimm, M. O., Willers, R., et al. (2007). Expression of heat shock protein 70 in renal cell carcinoma and its relation to tumor progression and prognosis. Histol. Histopathol. 22, 1099–1107. Küper, C., Steinert, D., Fraek, M. L., Beck, F. X., and Neuhofer, W. (2009). EGF receptor signaling is involved in expression of osmoprotective TonEBP target gene aldose reductase under hypertonic conditions. Am. J. Physiol. Renal Physiol. 296, F1100–F1108. doi: 10.1152/ajprenal.90402.2008 Rivard, C. J., Brown, L. M., Almeida, N. E., Maunsbach, A. B., Pihakaski- Maunsbach, K., Andres-Hernando, A., et al. (2007). Expression of the calcium- binding protein S100A4 is markedly up-regulated by osmotic stress and is August 2014 | Volume 5 | Article 293 | 9 www.frontiersin.org NFAT5 and renal cell carcinoma Küper et al. involved in the renal osmoadaptive response. J. Biol. Chem. August 2014 | Volume 5 | Article 293 | 10 Frontiers in Physiology | Integrative Physiology CONCLUSIONS Mol. Morphol. 20, 71–76. doi: 10.1097/PAI.0b013e31821 fc8b7 of S100A4 contributes to proliferation and migration of renal carcinoma cells. Front. Physiol. 5:293. doi: 10.3389/fphys.2014.00293 This article was submitted to Integrative Physiology, a section of the journal Frontiers in Physiology. Woo, S. K., Lee, S. D., Na, K. Y., Park, W. K., and Kwon, H. M. (2002). TonEBP/NFAT5 stimulates transcription of HSP70 in response to hypertonicity. Mol. Cell. Biol. 22, 5753–5760. doi: 10.1128/MCB.22.16.5753-5760.2002 Copyright © 2014 Küper, Beck and Neuhofer. This is an open-access article dis- tributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this jour- nal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Copyright © 2014 Küper, Beck and Neuhofer. This is an open-access article dis- tributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this jour- nal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Yang, H., Zhao, K., Yu, Q., Wang, X., Song, Y., and Li, R. (2012). Evaluation of plasma and tissue S100A4 protein and mRNA levels as potential markers of metastasis and prognosis in clear cell renal cell carcinoma. J. Int. Med. Res. 40, 475–485. doi: 10.1177/147323001204000209 August 2014 | Volume 5 | Article 293 | 10 Frontiers in Physiology | Integrative Physiology Frontiers in Physiology | Integrative Physiology
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Preferences and Perceptions in Provision and Maintenance Public Goods
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a b s t r a c t Article history: Received 28 October 2021 Available online 15 July 2022 JEL classification: C92 H41 Keywords: Maintenance and provision social dilemmas Conditional cooperation Kindness Misperceptions Experiments Framing We study two generic versions of public goods problems: in Provision problems, the public good does not exist initially and needs to be provided; in Maintenance problems, the public good already exists and needs to be maintained. In four lab and online experiments (n = 2,105), we document a robust asymmetry in preferences and perceptions in two incentive- equivalent versions of these public good problems. We find fewer conditional cooperators and more free riders in Maintenance than Provision, a difference that is replicable, stable, and reflected in perceptions of kindness. Incentivized control questions administered before gameplay reveal dilemma-specific misperceptions but controlling for them neither eliminates game-dependent conditional cooperation, nor differences in perceived kindness of others’ cooperation. Thus, even when sharing the same game form, Maintenance and Provision are different social dilemmas that require separate behavioral analyses. © 2022 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Simon Gächter a,b,c,∗, Felix Kölle d,∗, Simone Quercia e,∗ a University of Nottingham, Nottingham NG7 1BW, United Kingdom b CESifo, 81679 Munich, Germany c IZA, 53113 Bonn. Germany d University of Cologne, 50923 Cologne, Germany e University of Verona, 37129 Verona, Italy https://doi.org/10.1016/j.geb.2022.06.009 0899-8256/© 2022 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Games and Economic Behavior 135 (2022) 338–355 Games and Economic Behavior 135 (2022) 338–355 * Corresponding authors. E-mail addresses: simon.gaechter@nottingham.ac.uk (S. Gächter), felix.koelle@uni-koeln.de (F. Kölle), simone.quercia@univr.it (S. Quercia). Preferences and perceptions in Provision and Maintenance public goods Simon Gächter a,b,c,∗, Felix Kölle d,∗, Simone Quercia e,∗ * Corresponding authors. E-mail addresses: simon.gaechter@nottingham.ac.uk (S. Gächter), felix.koelle@uni-koeln.de (F. Kölle), simone.quercia@univr.it (S. Quercia). https://doi.org/10.1016/j.geb.2022.06.009 0899 8256/© 2022 Th A th ( ) P bli h d b El i I Thi i ti l d th CC BY li 1. Introduction In this paper, we study two generic forms of voluntary cooperation: providing initially inexistent public goods and main- taining existing ones. Contributing to charities, volunteering, being a team player, or participating in collective action, are examples of voluntary cooperation that provides public goods. Shared natural resources, known as “common-pool resources” (e.g., Ostrom, 1990), but also biodiversity and a stable climate, are important public goods that nature has provided but peo- ple need to limit extraction or environmentally damaging emissions if they want to maintain them. Similarly, public goods that previous generations created, such as democracy and the rule of law, only continue existing if people limit rule-bending, rent-seeking, and corruption. As the examples illustrate, “provision” and “maintenance” public goods differ along many dimensions. Crucially, however, for selfish players, they are all social dilemmas: providing or maintaining the public good is often collectively beneficial, but individual incentives are to hold back on provision and to exploit rather than to maintain the public good – the “tragedy of the commons” (Hardin, 1968). Although the comparison between these two problems has been studied both in economics and psychology (see, e.g., Sell and Son, 1997 and Dufwenberg et al., 2011), until recently, most studies only investigated S. Gächter, F. Kölle and S. Quercia Games and Economic Behavior 135 (2022) 338–355 cooperative behavior, and less the psychological mechanisms that produce cooperation.1 Here, we ask whether, from the perspective of social preferences and perceptions, maintenance and provision dilemmas are psychologically different social dilemmas. cooperative behavior, and less the psychological mechanisms that produce cooperation.1 Here, we ask whether, from the perspective of social preferences and perceptions, maintenance and provision dilemmas are psychologically different social dilemmas. Studying preferences and perceptions as drivers of cooperation and understanding whether their impact on cooperative behavior differs across maintenance and provision dilemmas is important from both a theoretical and practical point of view. 1. Introduction From a theoretical viewpoint, studying preferences and perceptions is interesting because it can help explain why people often cooperate even in anonymous one-shot games without communication, where mechanisms that can support cooperation, such as reputation or repeated interactions (e.g., Dal Bó and Fréchette, 2018; Rand and Nowak, 2013) do not apply (see, e.g., Fischbacher and Gächter, 2010; and Gächter et al., 2017 for evidence from the lab; and, e.g., Frey and Meier, 2004; Alpizar et al., 2008; Rustagi et al., 2010; Fehr and Leibbrandt, 2011 for evidence from the field). Do people cooperate because they misperceive their incentives in a social dilemma, or do they have a ‘genuine’ preference for cooperation? If people misunderstand their incentives, they may implement choices they otherwise would not. Thus, observing cooperation without controlling for perception of incentives may not be a conclusive revelation of a preference for cooperation (for related arguments see, e.g., Koszegi and Rabin, 2008 and Cason and Plott, 2014). Apart from potential differences in the understanding of the incentive structure, maintenance and provision might also differ in the way people perceive others’ actions, e.g., in terms of kindness. Perceptions of the kindness of other players’ actions are important because, in social dilemmas, they can explain why some people cooperate in the first place (e.g., Falk and Fischbacher, 2006). The practical relevance of our research question comes from the fact that any policy intervention aimed at fostering cooperation must rest on accurate behavioral mechanisms. If these mechanisms are dilemma-specific, this would imply that maintenance and provision might require different approaches to overcome the tragedy of the commons. To answer these questions, and to provide a comprehensive understanding of the fundamental nature of cooperation in maintenance and provision dilemmas, we present the results from four experiments, in which we study preferences and perceptions in conjunction. We compare two versions of a linear public good game that share the same game form: A Provision game and a Maintenance game. In Provision, the public good initially does not exist; four players in a group are endowed with 20 tokens each and decide simultaneously how many of them to contribute to the public good. In Maintenance, players have no endowment, but the public good already exists because 80 tokens are invested at the outset in the public good. Players decide simultaneously how many (up to 20) tokens to withdraw from the public good. 1. Introduction Any token contributed to the public good (in Provision) or not withdrawn from the public good (in Maintenance) is worth 1.6 money units to the group, which is then shared equally between group members; any token not contributed to the public good or withdrawn from the public good is worth 1 money unit.2 of preferences and perceptions in influencing cooperation in these two dilemmas, we proceed in marize in Table 1. To ascertain the role of preferences and perceptions in influencing cooperation in these two four steps that we summarize in Table 1. Our first step is to ensure that what we study is a replicable phenomenon (Drazen et al., 2021). This is the purpose of Experiment 1. In this experiment, we replicate the one-shot results of Gächter et al. (2017) using a diverse online subject pool (MTurk). We find that in a simultaneous one-shot game, people contribute 52% of their endowment in Provision com- pared to 39% in Maintenance, a difference that is highly statistically significant. Furthermore, using the Fischbacher et al. (2001) strategy-method experiment to separate beliefs from preferences, we replicate that there are systematically fewer conditional cooperators and more free riders in Maintenance than Provision. In two additional experiments (Experiments 2a and 2b in Table 1), we collect new evidence to test whether, within-participants, our measure of cooperation prefer- ences is stable over time and, together with beliefs, predicts contribution or withdrawal decisions in one-shot games played immediately or five months after preferences were elicited. In Steps 2 and 3 we turn to our central question of how people perceive others’ behavior (Step 2) and the incentives in the dilemmas (Step 3). Our second step measures people’s perceptions about the kindness of others’ behavior. While differences in kindness perceptions could support a preference interpretation, it is possible that some people misperceive the game form because they do not understand the material incentives of the public good game. Such “confusion” is likely because of previous evidence (e.g., Andreoni, 1995a; Houser and Kurzban, 2002; Ferraro and Vossler, 2010; Bayer et al., 2013). Moreover, irrespective of the game form, cooperation preferences as measured by the strategy method might be influenced by misperceptions (Burton-Chellew et al., 2016). Testing for misperception of incentives is our third step. 1 The behavioral evidence about cooperation in maintenance and provision dilemmas comes from largely separate literatures. For cooperation in main- tenance (common-pool resource) problems, see, e.g., the surveys by Ostrom (1990) and Ostrom (2006). Evidence on cooperation in public goods provision problems is surveyed in, e.g., Ledyard (1995); Gächter and Herrmann (2009); Chaudhuri (2011) and Fehr and Schurtenberger (2018). 2 We focus sharply on the social dilemma dimension of provision and maintenance public goods, and abstract from technological features (e.g., resource rivalry in common-pool resources vs. non-rivalrous public goods) and institutional details (rules and regulations) that define real-world social dilemmas (e.g., Ostrom, 1990; Cornes and Sandler, 1996; Poppe, 2005; Apesteguía and Maier-Rigaud, 2006; Levin, 2014). 1 The behavioral evidence about cooperation in maintenance and provision dilemmas comes from largely separate literatures. For cooperation in main- tenance (common-pool resource) problems, see, e.g., the surveys by Ostrom (1990) and Ostrom (2006). Evidence on cooperation in public goods provision problems is surveyed in, e.g., Ledyard (1995); Gächter and Herrmann (2009); Chaudhuri (2011) and Fehr and Schurtenberger (2018). 2 We focus sharply on the social dilemma dimension of provision and maintenance public goods, and abstract from technological features (e.g., resource rivalry in common-pool resources vs. non-rivalrous public goods) and institutional details (rules and regulations) that define real-world social dilemmas (e.g., Ostrom, 1990; Cornes and Sandler, 1996; Poppe, 2005; Apesteguía and Maier-Rigaud, 2006; Levin, 2014). Table 1 Table 1 Four steps to test whether Maintenance and Provision are different dilemmas. Measure how kind or unkind people perceive a certain cooperation level to be. Measured on a scale of -100 (=very unkind) to +100 (= very kind) Measure with 8 incentivized questions about payoffs and goals how people perceive the incentives in the public good game. Control for misperceptions to test for potential differences in cooperative preferences * Data taken from https://doi .org /10 .5061 /dryad .8d9t2. ences using the strategy method by Fischbacher et al. (2001).3 Controlling for people’s misunderstanding will then allow us to test whether cooperation preferences continue to differ statistically significantly between Maintenance and Provision. Our fourth step is to discuss how various theories of social preferences can explain our results. ences using the strategy method by Fischbacher et al. (2001).3 Controlling for people’s misunderstanding will then allow us to test whether cooperation preferences continue to differ statistically significantly between Maintenance and Provision. Our fourth step is to discuss how various theories of social preferences can explain our results. Our paper offers several contributions to the literature. Our methodology of holding the nature of the social dilemma constant relates us to literatures on framing and context effects in other-regarding behavior.4 More specifically, our focus on provision/maintenance of public goods leads us naturally to a design that is a version of what psychologists (Dawes, 1980) have called “take-some” vs. “give-some” dilemmas (e.g., Sell and Son, 1997; van Dijk and Wilke, 1997; Sonnemans et al., 1998; Messer et al., 2007; Cubitt et al., 2011a; Dufwenberg et al., 2011; Cox, 2015; Cox and Stoddard, 2015; Fosgaard et al., 2014; Fosgaard et al., 2017; Khadjavi and Lange, 2015; Isler et al., 2021). Our maintenance/provision design differs from designs that manipulate whether the positive externality of contributing to the public good or the negative externality of not contributing is emphasized. Papers in this line of research are Andreoni (1995b); Park (2000); and Fujimoto and Park (2010). For a comparative discussion of give/take or positive/negative externality framing effects and an overview of studies see Cartwright (2016).5 Different from most early literature on give-some and take-some games, our analysis consists of separating preferences and perceptions as determinants of cooperation rather than focusing only on cooperation decisions. 3 To measure confusion, previous studies used various experimental designs, like changed incentive structures (Andreoni, 1995a), information conditions (Bayer et al., 2013), or computerized players (Houser and Kurzban, 2002; Ferraro and Vossler, 2010; Burton-Chellew et al., 2016). Fosgaard et al. (2017) used an incentivized post-experimental questionnaire. 4 Our focus is on public goods games, but also relates to the importance of context effects. For instance, previous evidence from dictator games reveals that people are less willing to give if the choice set also includes the option to take away money (List, 2007; Bardsley, 2008; Cappelen et al., 2013; Dreber et al., 2013; Korenok et al., 2014; Bicchieri et al., 2022). Also, the approval of egoistic behavior seems to be context-dependent too, e.g., in markets vs. non-market settings (Bartling et al., 2021). 5 Another dimension of framing effects is due to attaching labels to games (e.g., “Wallstreet vs Community game”; e.g., Ellingsen et al., 2012 and Dufwenberg et al., 2011). In this paper we use neutral labels. 6 Our focus on social preferences and (mis-)perception does not deny the possibility that cognitive ability, risk preferences and loss aversion might matter too (e.g., De Dreu and McCusker, 1997; Iturbe-Ormaetxe et al., 2011), but we leave this for future research, not least to keep this paper manageable. ming effects is due to attaching labels to games (e.g., “Wallstreet vs Community game”; e.g., Ellingsen et al., 2012 an his paper we use neutral labels. 1. Introduction To this end, we designed a set of eight incentivized control ques- tions that people answered after they had correctly solved ten standard understanding questions covering payoffs in the public good game. We administered the incentivized control questions before we measured participants’ cooperation prefer- 339 Games and Economic Behavior 135 (2022) 338–355 S. Gächter, F. Kölle and S. Quercia Table 1 Four steps to test whether Maintenance and Provision are different dilemmas. Table 1 Four steps to test whether Maintenance and Provision are different dilemmas. Exp. Experiment Number of participants Subject pool Purpose Step 1: Establishing the replicability and stability of cooperative preferences (Section 3) 0 Gächter et al. (2017)* (n = 703) Students (UoN) These data provide a previous benchmark result, which we replicate in Experiment 1 1 Replication study n = 704 US citizens (MTurk) Assess whether Experiment 0 with students can be replicated in a non-student subject pool 2a Temporal stability (5 months delay) n = 119 Students (UoN, sampled from experiment 0) Assess the role of stability of conditionally cooperative preferences over time 2b Predictive power of cooperation attitudes n = 116 Students (UoN, sampled from experiment 4) Assess the predictive power of conditionally cooperative preferences plus beliefs to explain actual cooperation levels Step 2: Measuring perceptions of kindness (Section 4) 3 Kindness survey n = 185 Students (UoN, new participants) Measure how kind or unkind people perceive a certain cooperation level to be. Measured on a scale of -100 (=very unkind) to +100 (= very kind) n = 401 US citizens (MTurk, new participants) Step 3: Measuring game form misperceptions and controlling for them (Section 5) 4 Dilemma-specific game-form misperceptions n = 696 Students (UoN, new participants) Measure with 8 incentivized questions about payoffs and goals how people perceive the incentives in the public good game. Control for misperceptions to test for potential differences in cooperative preferences Step 4: Assessing theoretical explanations (Section 6) * Data taken from https://doi .org /10 .5061 /dryad .8d9t2. 5 Another dimension of framing effects is due to attaching labels to games (e.g., “Wallstreet vs Community game”; e.g., Ellingsen et al., 2012 and Dufwenberg et al., 2011). In this paper we use neutral labels. 6 Our focus on social preferences and (mis-)perception does not deny the possibility that cognitive ability, risk preferences and loss aversion might matter too (e.g., De Dreu and McCusker, 1997; Iturbe-Ormaetxe et al., 2011), but we leave this for future research, not least to keep this paper manageable. 6 Our focus on social preferences and (mis-)perception does not deny the possibility that cognitive ability, risk preferences and loss aversion might matter too (e.g., De Dreu and McCusker, 1997; Iturbe-Ormaetxe et al., 2011), but we leave this for future research, not least to keep this paper manageable. 3 To measure confusion, previous studies used various experimental designs, like changed incentive structures (Andreoni, 1995a), information conditions (Bayer et al., 2013), or computerized players (Houser and Kurzban, 2002; Ferraro and Vossler, 2010; Burton-Chellew et al., 2016). Fosgaard et al. (2017) used an incentivized post-experimental questionnaire. 4 s and (mis-)perception does not deny the possibility that cognitive ability, risk preferences and loss aversion might matter 997; Iturbe-Ormaetxe et al., 2011), but we leave this for future research, not least to keep this paper manageable. 2. The basic setup and the proxy for cooperation preferences Our setup consists of the two social dilemmas described above, Provision and Maintenance. In both conditions, partici- pants are randomly assigned to groups of n = 4. In Provision, each group member i is endowed with 20 tokens, which they can either keep or (partly or fully) contribute (ci) to a “group project”. Contributions to the group project are summed up, multiplied by a factor of 1.6, and distributed equally among the four members. Equation (1) describes the material incentives of individual i: πi = 20 −ci + 1.6 4 4  j=1 c j. (1) In Maintenance, 80 tokens are initially placed in a “group project”. Each group member i decides about the allocation of 20 tokens, which they can either leave or (partially or fully) withdraw (wi) from the project. Material incentives are described by equation (2): πi = wi + 1.6 4 (80 − 4  j=1 w j). (2) πi = wi + 1.6 4 (80 − 4  j=1 w j). (2) If people are only motivated by material incentives, (1) and (2) are incentive-equivalent social dilemmas because ci = 20 – wi. Furthermore, because the material costs of cooperation outweigh its benefits, both the Maintenance and Provision dilemma have full free-riding (ci = 0; wi = 20) as the unique Nash equilibrium in dominant strategies, no matter what other members of their group (are believed to) do. All experiments were based on these two incentive-equivalent social dilemmas and consisted of several parts. In the first part of each experiment, participants were introduced to the basic decision situation explaining either the Maintenance or the Provision dilemma and its incentive structure, that is, each participant only faced one of the two social dilemmas (between-subjects design). To ensure understanding, participants then had to complete a set of ten computerized control questions. Only after correctly answering all of them, participants could proceed with the experiment. The exact design of the remaining parts differed across our experiments.7 In most of our experiments, in the second part we implemented a strategy-method public goods game (described below) through which we measure cooperation attitudes, our main proxy for cooperation preferences. Some of the sessions in these experiments included a third part in which participants played a direct-response game in which they simultaneously had to state their contribution decision and belief about others’ contributions. 7 At the beginning of the experiment, participants were told that the experiment consists of several parts, but that the details about later parts would be disclosed only after they had completed the respective parts. The different designs of the later parts could therefore not affect behavior in previous parts. 8 As a robustness check, we used an alternative classification method by Thöni and Volk (2018), who proposed a refinement of the criteria of Fischbacher et al. (2001). All results are qualitatively and quantitatively in line with those reported below. Table 1 With regard to prefer- ences, our paper joins the small literature that elicits preferences for conditional cooperation in maintenance or provision problems (e.g., Frackenpohl et al., 2016; Gächter et al., 2017; Fosgaard et al., 2014; Fosgaard et al., 2017; Isler et al., 2021). Our experiments also measure the perception of incentives before we elicit preferences for cooperation. This heeds argu- ments by Koszegi and Rabin (2008) and Cason and Plott (2014) that measuring preferences requires controlling for the perception of incentives.6 Our goals relate us to Fosgaard et al. (2017). They also measure preferences for conditional cooperation and misper- ceptions albeit after the elicitation of preferences and with fewer questions. Theirs is a representative subject pool from Denmark (n = 2, 042), whereas we present evidence from a student subject pool in the UK and online workers (MTurk) from the general population in the US (total n = 2, 105). More importantly, unlike Fosgaard et al. (2017), we report evi- dence on the temporal stability of preferences, perceptions of kindness and guilt, and link our results to theories of social preferences. Our four-step analysis that combines lab and online experiments, replications, between and within-subject sta- 340 S. Gächter, F. Kölle and S. Quercia Games and Economic Behavior 135 (2022) 338–355 bility tests, measurement of perceptions of kindness as well as of the incentives in the games, establishes that Maintenance and Provision are different social dilemmas even when sharing the same game form and when controlling for possible misperceptions of incentives. bility tests, measurement of perceptions of kindness as well as of the incentives in the games, establishes that Maintenance and Provision are different social dilemmas even when sharing the same game form and when controlling for possible misperceptions of incentives. 2. The basic setup and the proxy for cooperation preferences In the experiments in which we elicited game-form misperceptions, the strategy-method game in part 2 was preceded by a set of incentivized control questions. In the following, we explain how we elicited cooperation attitudes, which is our main variable of interest. All instructions and control questions are in Online Appendix A. To elicit a proxy for cooperation preferences we used the design introduced by Fischbacher et al. (2001), which employs a variant of the strategy method (Selten, 1967). This design elicits an individual’s willingness to cooperate as a function of other group members’ cooperation. Participants played a one-shot version of the game and were asked to make an un- conditional and a conditional contribution (or withdrawal) decision. In the unconditional decision, participants chose one contribution or withdrawal level. In the conditional decision, participants were asked to fill in a table in which they had to indicate their contribution (or withdrawal) decision for each possible (rounded) average contribution (or withdrawal) of the other three group members. To guarantee incentive compatibility, in each group a random mechanism selected three members for whom the unconditional decision was payoff-relevant and one member for whom the conditional decision was payoff-relevant. For this participant, the conditional decision was calculated according to the (rounded) average uncon- ditional decision of the other three group members. The incentive-compatibly elicited attitudes are a proxy for cooperation preferences in the sense that they measure people’s willingness to pay for conditional cooperation. Following Fischbacher et al. (2001), we classify a participant as a (i) conditional cooperator if their contribution/withdrawal schedule exhibits a (weakly) monotonically increasing pattern, or if the Spearman correlation coefficient between their schedule and the others’ average contribution (or withdrawal) is positive and significant at p < 0.01; (ii) a free rider if they never contribute anything or withdraw everything irrespective of how much the others contribute (or withdraw); and (iii) as other if none of the criteria in (i) & (ii) apply.8 341 S. Gächter, F. Kölle and S. Quercia Games and Economic Behavior 135 (2022) 338–355 Our data come from four experiments and three main sources: the CeDEx lab at the University of Nottingham; the online labor market platform Amazon Mechanical Turk (MTurk); and online experiments conducted with students at the University of Nottingham (see Table 1 for an overview of our experiments). We used z-Tree (Fischbacher, 2007) for conducting the laboratory sessions. 2. The basic setup and the proxy for cooperation preferences For the online experiments on MTurk and the University of Nottingham, we used the survey software Qualtrics. For the lab and online experiments at Nottingham, we recruited student participants (average age 20.2 years; 58% female) from various disciplines at the University of Nottingham using the software ORSEE (Greiner, 2015). Students were only allowed to participate in one lab or online session. On MTurk, participants (all US residents) were 31.9 years old and 41% were female.9 Average payments were £20.60 for lab sessions, and $2.60 for MTurk sessions (corresponding to an hourly wage of $13.00). 3. Step 1: replicability and stability of preferences in Maintenance and Provision We start by summarizing the findings from our previous study (Gächter et al., 2017). We then compare these results with an online replication study conducted on MTurk. Being able to replicate the basic phenomenon we want to study is an important first step in our analysis.10 After that, we show that cooperation preferences are not only stable between different subject pools but are also stable over time within participants. Finally, we investigate the predictive power of the elicited cooperation preferences for simultaneous gameplay and compare it across Maintenance and Provision. All procedural details and further supporting evidence are in Online Appendix B1. 11 The category ‘others’ contains “unconditional cooperators” who contribute a constant positive amount irrespective of what other group members contribute, “anti-conditional cooperators” whose cooperation depends negatively on the cooperation of other group members, “triangle cooperators” who are conditionally cooperative up to a certain level when they turn into anti-conditional and the rest. See Online Appendix B1 for further details and the relative frequencies of these subtypes. 9 See Horton et al. (2011) and Arechar et al. (2018) for a detailed description of MTurk, and a comparison of MTurk versus lab experiments. Both studies as well as Snowberg and Yariv (2021) demonstrate that behavior in a variety of games is similar on MTurk and the lab. 10 See Maniadis et al. (2014), Camerer et al. (2016), Camerer et al. (2019), and Drazen et al. (2021) on the importance of replicability in experimental economics. 11 The category ‘others’ contains “unconditional cooperators” who contribute a constant positive amount irrespective of what other group members contribute, “anti-conditional cooperators” whose cooperation depends negatively on the cooperation of other group members, “triangle cooperators” who are conditionally cooperative up to a certain level when they turn into anti-conditional and the rest. See Online Appendix B1 for further details and the relative frequencies of these subtypes. 12 We decided to replicate the findings of Gächter et al. (2017) with a planned sample size of n = 700 because we were interested in the robustness of our lab results with undergraduates in a much more diverse subject pool. Based on the differences in the type distributions in the left panel of Fig. 1, a sample size of n = 215 would have sufficed to detect the same effect size with a power of 0.99 at α = 0.001 (calculations based on G*Power 3.1, Faul et al., 2007). However, given the different socio-demographic characteristics of the subject pool and the online nature of the experiment in MTurk, we decided to increase the sample to n = 700. 13 The different levels of the frequency of types across our two studies is not surprising given the different cultural and sociodemographic background of the participants. We note, however, that the results from our MTurk study are very similar to Kocher et al. (2008) who elicited cooperation types among US students using a Provision public goods game: When comparing their results to ours, we find a remarkably similar distribution of types (χ 2(2) = 0.02; p = 0.992): 81% vs. 80% conditional cooperators, 8% vs. 8% free riders, and 11% vs. 12% others. We thank M. Kocher for providing the data. Disaggregating the category ‘others’ in our MTurk data shows similar results than in Gächter et al. (2017). See Table B1 (Panel B) in Online Appendix B. 14 We note that the differences across Maintenance and Provision are somewhat less pronounced in the MTurk sample compared to the student sample: the difference in the share of conditional cooperators amounts to 13 and 20 percentage points, respectively; the difference in the share of free riders is 8 and 11 percentage points, resp.; and the difference in the share of others is 4 and 11 percentage points, resp.. To test whether these differences across the two samples are significant, we run logistic regressions in which we use the different types as dependent variable, a treatment dummy, a MTurk dummy, and an interaction between the latter two as independent variables. The results, reported in Table B2 in Online Appendix B, confirm that there are significantly more conditional cooperators and significantly less free riders and others in Provision than Maintenance and on MTurk, but that there are no significant interaction effects (Provision × MTurk). 9 See Horton et al. (2011) and Arechar et al. (2018) for a detailed description of MTurk, and a comparison of MTurk versus lab experiments. Both studies as well as Snowberg and Yariv (2021) demonstrate that behavior in a variety of games is similar on MTurk and the lab. 10 See Maniadis et al. (2014), Camerer et al. (2016), Camerer et al. (2019), and Drazen et al. (2021) on the importance of replicability in experimental economics. increase the sample to n = 700. 13 The different levels of the frequency of types across our two studies is not surprising given the different cultural and sociodemographic background of the participants. We note, however, that the results from our MTurk study are very similar to Kocher et al. (2008) who elicited cooperation types among US students using a Provision public goods game: When comparing their results to ours, we find a remarkably similar distribution of types (χ 2(2) = 0.02; p = 0.992): 81% vs. 80% conditional cooperators, 8% vs. 8% free riders, and 11% vs. 12% others. We thank M. Kocher for providing the data. Disaggregating the category ‘others’ in our MTurk data shows similar results than in Gächter et al. (2017). See Table B1 (Panel B) in Online Appendix B. 14 We note that the differences across Maintenance and Provision are somewhat less pronounced in the MTurk sample compared to the student sample: the difference in the share of conditional cooperators amounts to 13 and 20 percentage points, respectively; the difference in the share of free riders is 8 and 11 percentage points, resp.; and the difference in the share of others is 4 and 11 percentage points, resp.. To test whether these differences across the two samples are significant, we run logistic regressions in which we use the different types as dependent variable, a treatment dummy, a MTurk dummy, and an interaction between the latter two as independent variables. The results, reported in Table B2 in Online Appendix B, confirm that there are significantly more conditional cooperators and significantly less free riders and others in Provision than Maintenance and on MTurk, but that there are no significant interaction effects (Provision × MTurk). 0 See Maniadis et al. (2014), Camerer et al. (2016), Camerer et al. (2019), and Drazen et al. (2021) on the importance o conomics. 1 h h d l h b are conditionally cooperative up to a certain level when they turn into anti conditional and the rest. See Online Appendix B1 for further details and the relative frequencies of these subtypes. 12 We decided to replicate the findings of Gächter et al. (2017) with a planned sample size of n = 700 because we were interested in the robustness of our lab results with undergraduates in a much more diverse subject pool. Based on the differences in the type distributions in the left panel of Fig. 1, a sample size of n = 215 would have sufficed to detect the same effect size with a power of 0.99 at α = 0.001 (calculations based on G*Power 3.1, Faul et al., 2007). However, given the different socio-demographic characteristics of the subject pool and the online nature of the experiment in MTurk, we decided to increase the sample to n = 700. 13 The different levels of the frequency of types across our two studies is not surprising given the different cultural and sociodemographic background of the participants. We note, however, that the results from our MTurk study are very similar to Kocher et al. (2008) who elicited cooperation types among US students using a Provision public goods game: When comparing their results to ours, we find a remarkably similar distribution of types (χ 2(2) = 0.02; p = 0.992): 81% vs. 80% conditional cooperators, 8% vs. 8% free riders, and 11% vs. 12% others. We thank M. Kocher for providing the data. Disaggregating the category ‘others’ in our MTurk data shows similar results than in Gächter et al. (2017). See Table B1 (Panel B) in Online Appendix B. 14 We note that the differences across Maintenance and Provision are somewhat less pronounced in the MTurk sample compared to the student sample: the difference in the share of conditional cooperators amounts to 13 and 20 percentage points, respectively; the difference in the share of free riders is 8 and 11 percentage points, resp.; and the difference in the share of others is 4 and 11 percentage points, resp.. To test whether these differences across the two samples are significant, we run logistic regressions in which we use the different types as dependent variable, a treatment dummy, a MTurk dummy, and an interaction between the latter two as independent variables. The results, reported in Table B2 in Online Appendix B, confirm that there are significantly more conditional cooperators and significantly less free riders and others in Provision than Maintenance and on MTurk, but that there are no significant interaction effects (Provision × MTurk). 9 See Horton et al. (2011) and Arechar et al. (2018) for a detailed description of MTurk, and a comparison of MTurk ve as well as Snowberg and Yariv (2021) demonstrate that behavior in a variety of games is similar on MTurk and the lab. 12 We decided to replicate the findings of Gächter et al. (2017) with a planned sample size of n = 700 because we were interested in the robustness of our lab results with undergraduates in a much more diverse subject pool. Based on the differences in the type distributions in the left panel of Fig. 1, a sample size of n = 215 would have sufficed to detect the same effect size with a power of 0.99 at α = 0.001 (calculations based on G*Power 3.1, Faul et al., 2007). However, given the different socio-demographic characteristics of the subject pool and the online nature of the experiment in MTurk, we decided to increase the sample to n = 700. See Horton et al. (2011) and Arechar et al. (2018) for a detailed description of MTurk, and a comparison of MTurk versus lab experiments. Both studies as well as Snowberg and Yariv (2021) demonstrate that behavior in a variety of games is similar on MTurk and the lab. 10 See Maniadis et al. (2014), Camerer et al. (2016), Camerer et al. (2019), and Drazen et al. (2021) on the importance of replicability in experimental economics. 12 We decided to replicate the findings of Gächter et al. (2017) with a planned sample size of n = 700 because we were interested in the robustness of our lab results with undergraduates in a much more diverse subject pool. Based on the differences in the type distributions in the left panel of Fig. 1, a sample size of n = 215 would have sufficed to detect the same effect size with a power of 0.99 at α = 0.001 (calculations based on G*Power 3.1, Faul et al., 2007). However, given the different socio-demographic characteristics of the subject pool and the online nature of the experiment in MTurk, we decided to increase the sample to n = 700. 13 The different levels of the frequency of types across our two studies is not surprising given the different cultural and sociodemographic background of the participants. We note, however, that the results from our MTurk study are very similar to Kocher et al. (2008) who elicited cooperation types among US students using a Provision public goods game: When comparing their results to ours, we find a remarkably similar distribution of types (χ 2(2) = 0.02; 3.1. Gächter et al. (2017) and a replication on MTurk 3.1. Gächter et al. (2017) and a replication on MTurk The left panel of Fig. 1 summarizes the main relevant finding for our paper from Gächter et al. (2017), which was based on a one-shot strategy method experiment as described in Section 3. Participants were significantly more likely to be conditional cooperators (χ 2(1) = 31.03; p < 0.001) and significantly less likely to be free riders (χ 2(1) = 10.46; p = 0.001) and others (χ 2(1) = 11.08; p = 0.001) in Provision than in Maintenance.11 In a one-shot direct response game played after the type elicitation, Gächter et al. (2017) further found that cooperation rates were significantly higher in Provision than in Maintenance (41% vs. 30%; two-sided t-test: p = 0.007). Our replication for the purposes of this paper was conducted on MTurk with n = 703 US participants (instructions are in Online Appendix A).12 The results match our previous findings. While the levels in the frequency of types are different compared to our UK student sample – we observe more conditional cooperators (73% vs. 53%, χ 2(1) = 62.21; p < 0.001) and less free riders (13% vs. 22%, χ 2(1) = 23.26; p < 0.001) and others (14% vs. 24%, χ 2(1) = 24.97; p < 0.001) on MTurk - treatment differences are highly significant.13 Specifically, as shown in the right panel of Fig. 1, in line with Gächter et al. (2017), we find a significantly different distribution of types across treatments (χ 2(2) = 15.96, p < 0.001) with a larger fraction of conditional cooperators (80% vs. 67%, χ 2(1) = 14.75; p < 0.001), and a lower fraction of free riders (8% vs. 17%, χ 2(1) = 10.75; p = 0.001) and others (12% vs. 16%, χ 2(1) = 3.07; p = 0.080) in Provision compared to Maintenance.14 Like in our previous study, we also find that effective cooperation rates (after contributions/withdrawals), measured in a one-shot direct-response game played after the type elicitation, are significantly higher in Provision than in Maintenance (52% vs. 39%, two-sided t-test: p < 0.001). In both samples, we also find unconditional contributions in the strategy method 342 Games and Economic Behavior 135 (2022) 338–355 S. Gächter, F. Kölle and S. Quercia Fig. 1. Distribution of cooperation types. Left panel: n = 704 students from the UK (source: Gächter et al. (2017)). 3.2. Temporal stability To test whether the observed difference in the distribution of types is also stable within participants, we ran an additional experiment in which we re-invited a subset of participants from the Gächter et al. (2017) sample (left panel of Fig. 1) four months after their first participation. Without knowing in advance, participants took part in sessions that were identical to the ones in which they participated before. We report results from n = 119 participants (n = 65 in Provision and n = 54 in Maintenance) who showed up in both waves. At the aggregate level, cooperation preferences are remarkably stable over a period of four months; the distribution of types within treatments is very similar and does not significantly change between waves, neither in Maintenance (χ 2(2) = 0.51, p = 0.776) nor Provision (χ 2(2) = 1.57, p = 0.456). Consequently, when comparing the distribution of types across treatments, we find a significantly different distribution across Maintenance and Provision for both Wave 1 and Wave 2 (χ 2(2) = 10.32, p = 0.006 and χ 2(2) = 11.87, p = 0.003, respectively; see also Table B3 in Online Appendix B). Regarding individual-level stability of cooperation preferences, we find that in Provision 66% of participants are classified as the same type in both waves, compared to 59% in Maintenance, a difference that is not statistically significant (χ 2(1) = 0.60, p = 0.438). While these numbers indicate that the stability of types across waves is clearly not perfect, for both treatments we find it to be significantly higher than chance (which amounts to 46% and 35%, in Provision and Maintenance, resp.; t-tests, both p < 0.001; see Table B4 in Online Appendix B). The stability rate in Provision is similar to Volk et al. (2012) who, using a similar setup and a gap of 2.5 months between waves, find a stability rate of 64%. No such comparison is possible for Maintenance because, as far as we are aware of, no previous study has investigated the stability of cooperation preferences using a maintenance dilemma. 3.1. Gächter et al. (2017) and a replication on MTurk Right panel: n = 703 US participants from MTurk (source: new experiments). p-values from χ 2-tests. Fig. 1. Distribution of cooperation types. Left panel: n = 704 students from the UK (source: Gächter et al. (2017)). Right panel: n = 703 US participants from MTurk (source: new experiments). p-values from χ 2-tests. to differ significantly across both dilemmas (Lab: Provision: 42%, Maintenance: 34%, two-sided t-test: p = 0.003; MTurk: Provision: 53%, Maintenance: 38%, two-sided t-test: p < 0.001). to differ significantly across both dilemmas (Lab: Provision: 42%, Maintenance: 34%, two-sided t-test: p = 0.003; MTurk: Provision: 53%, Maintenance: 38%, two-sided t-test: p < 0.001). 3.2. Temporal stability 3.3. Predictive power of cooperation preferences If our proxy for cooperation preferences measures something fundamental about people’s attitude towards cooperation, it should be predictive of actual behavior in another comparable environment. To test this, we rely on the third part of our experiment in which a subset of participants took part in a one-shot direct-response public goods game in which they made a single contribution decision. We also elicited incentivized beliefs about the average contribution of the other group members. Following Fischbacher et al. (2012), by combining elicited cooperation attitudes with stated beliefs we can 343 S. Gächter, F. Kölle and S. Quercia Games and Economic Behavior 135 (2022) 338–355 Fig. 2. Deviations from predicted choices in Maintenance and Provision. Left panel: Students (n = 288). Middle panel: MTurk (n = 703). Right panel: Students who participated in the direct-response experiment five months after the preference elicitation experiment (n = 116). Games and Economic Behavior 135 (2022) 338–355 S. Gächter, F. Kölle and S. Quercia Fig. 2. Deviations from predicted choices in Maintenance and Provision. Left panel: Students (n = 288). Middle panel: MTurk (n = 703). Right panel: Students who participated in the direct-response experiment five months after the preference elicitation experiment (n = 116). make a point prediction about the contribution decision, ˆci. We then compare ˆci with ci (i’s actual contribution in the direct-response game), delivering an individual-level measure of consistency. In total, we have (1) n = 288 observations from our Gächter et al. (2017) sample, and (2) n = 703 observations from our MTurk experiment.15 We further report data from (3) a set of n = 116 participants, for which the elicitation of cooperation preferences and the direct-response game took place in two separate sessions that lay five months apart. To our knowledge, this is the first paper that undertakes such a test of temporal stability. Our results are shown in Fig. 2, depicting the distribution of individual deviations from predicted choices, ci −ˆci, separately for Maintenance and Provision and for each of the three samples. Fig. 2 reveals that in all cases the modal and the median deviation is zero, that is, participants’ contribution decision in the direct-response game is perfectly consistent with their predicted contribution from the strategy-method, even after a delay of 5 months. 15 The remaining participants from Gächter et al. (2017) played a repeated game. The results on the predicted power for the first-period contributions are similar to the one reported here (see Gächter et al., 2017). 3.3. Predictive power of cooperation preferences While not all participants are completely consistent (see Online Appendix B for further details), for none of the three samples the distribution of deviations is significantly different across Maintenance and Provision (Kolmogorov Smirnov tests; Lab: p = 0.195; MTurk: p = 0.532; Lab (5 months): p = 0.472). Overall, this demonstrates that the elicited attitudes are, together with elicited beliefs, an equally good predictor of actual cooperation behavior in both Maintenance and Provision. 16 Since we asked participants for their personal perceptions, answers were not incentivized. However, we did incentivize participation. Student partici- pants were offered three randomly drawn prizes of £50 each. MTurkers received a flat payment of $2. According to Cubitt et al. (2011b) who studied moral judgments in social dilemmas, incentivizing participation does not affect moral judgments, making it unlikely that it affects kindness evaluations. 3.4. Discussion Consistent with the evidence from Frackenpohl et al. (2016) and Fosgaard et al. (2017), in Gächter et al. (2017) we have shown that Maintenance and Provision dilemmas elicit systematically different cooperation attitudes with significantly fewer participants behaving conditionally cooperative in the former than in the latter. In Gächter et al. (2017) we have further shown that together with differences in the beliefs about others’ cooperation, this translates into different levels of cooperation in both one-shot and repeated games. We extend this prior evidence by showing that (i) differences in cooperation attitudes across Maintenance and Provision are replicable across different subject pools, (ii) elicited attitudes in both dilemmas are equally stable within participants over a period of four months, and (iii) elicited attitudes are (jointly with beliefs) an equally good predictor of actual cooperation decision in both dilemmas, even after a delay of five months. We summarize these findings in our first result: 344 Games and Economic Behavior 135 (2022) 338–355 S. Gächter, F. Kölle and S. Quercia Gächter, F. Kölle and S. Quercia Games and Economic Behavior 135 (2022) 338–3 Fig. 3. Kindness perceptions in Provision and Maintenance of others’ effective contributions (±1 s.e.m). Fig. 3. Kindness perceptions in Provision and Maintenance of others’ effective contributions (±1 s.e.m). Result 1: Maintenance and Provision evoke systematically different cooperation attitudes. Most importantly, conditional coop- eration is more frequent in Provision than Maintenance. The elicited attitudes are stable within individuals and, jointly with beliefs, predictive of actual cooperation decisions. Result 1: Maintenance and Provision evoke systematically different cooperation attitudes. Most importantly, conditional coop- eration is more frequent in Provision than Maintenance. The elicited attitudes are stable within individuals and, jointly with beliefs, predictive of actual cooperation decisions. While replicability, stability, and predictive power are necessary conditions to interpret the effects as differences in underlying social preferences, they are not sufficient. An alternative interpretation of the observed differences is that they are due to stable and systematic misperceptions of the game form. In the next two steps (and sections), we disentangle the relative importance of social preferences and misperceptions. We start in the next section by investigating whether the differences between Provision and Maintenance can be related to different social perceptions across the two contexts. 5.1. Conceptualization of game form misperceptions 5.1. Conceptualization of game form misperceptions 5.1. Conceptualization of game form misperceptions Our conceptualization of game-form misperceptions draws on Cason and Plott (2014). They analyze the tension between standard theory, which assumes that preferences are only influenced by elements of the game form (i.e., the set of actions, the set of material consequences, and the links between actions and consequences), and non-standard theories, which postulate that preferences may depend on elements outside the game form such as how the game form is described. In their example, Cason and Plott investigate anomalous bidding behavior in the Becker et al. (1964) mechanism. While observed bids are consistent with frame-dependent preferences, Cason and Plott show that this effect is driven by a subset of participants who mistakenly perceive the situation as a first-price auction rather than a second-price auction. They conclude that in their case, the description of the decision situation affected participants’ perception of the game form, which, in turn, led them to implement ‘wrong’ behavioral responses given their underlying preferences. Cason and Plott’s general conclusion is that researchers should be careful when interpreting choices as revealed preferences, an issue that Koszegi and Rabin (2008) also point out. The implication of Cason and Plott’s argument for our context is that interpreting differences in behavioral responses across treatments as evidence for dilemma-dependent preferences might be erroneous because such differences can be due to dilemma-dependent misperceptions of the game form. If failure of correct game-form recognition is also at work in our setup, which is possible given previous evidence on confusion (see Introduction), then the observed distribution of cooperation types might not reflect participants’ true cooperation preferences as some of the participants might have mis- takenly implemented behavior different from their preferred one. For example, if some participants erroneously believe that to maximize their individual income, they should increase their contribution if the contributions of other group members increase, this might lead to an inflated rate of conditional cooperation. Moreover, if this type of game-form misperception is more frequent in Provision than in Maintenance, this could explain the observed treatment effect of a higher frequency of conditional cooperation and a lower frequency of free riding in the former than the latter. Some evidence for this possibility comes from Fosgaard et al. 5.1. Conceptualization of game form misperceptions (2017) who find that many participants fail to recognize the dominant strategy of full free-riding and that this type of mistake occurs more frequently in Provision than in Maintenance. In the next subsection, we describe the details of a new experiment that was specifically designed to examine the role of misperceptions in our context. 4. Step 2: perceptions of kindness in Maintenance and Provision In these cases, payoff equivalent actions are considered as unkinder in Maintenance compared to Provision (two-sided t-tests, average others’ contribution = 10, p = 0.045 and p = 0.001 for students and MTurkers, respectively; average others’ contribution = 20, p = 0.007 and p = 0.062 for students and MTurkers, respectively). pattern for medium and high effective contributions of 10 and 20, respectively. In these cases, payoff equivalent actions are considered as unkinder in Maintenance compared to Provision (two-sided t-tests, average others’ contribution = 10, p = 0.045 and p = 0.001 for students and MTurkers, respectively; average others’ contribution = 20, p = 0.007 and p = 0.062 for students and MTurkers, respectively). Further support comes from OLS regressions in which we use kindness evaluations as the dependent variable, others’ average contributions, a dummy for Provision, and an interaction term of the last two as independent variables. We run this regression separately for each subject pool. The results are in Table B5 in Online Appendix B. In line with Fig. 3, we find a positive and significant coefficient for the interaction term, indicating greater responsiveness of kindness evaluations to others’ contributions in Provision than in Maintenance. We summarize these findings in our second result: Result 2: Maintenance and Provision evoke systematically different perceptions of kindness: Complete free-riding is perceived to be unkinder in Provision than in Maintenance, while positive contributions (of 10 and 20) are perceived as more kind in Provision than in Maintenance. Overall, Result 2 suggests that both with respect to kindness and unkindness, individuals have stronger reactions in their perception of others’ contributions when contributing to, rather than withdrawing from, a public good. Result 2 is also con- sistent with Cubitt et al. (2011b) who found a similar pattern for moral judgments: Failing to contribute to the public good was perceived as morally worse than withdrawing everything. These stronger reactions likely trigger a stronger need to re- ciprocate and, hence, can explain the higher frequency of conditional cooperators in Provision compared to Maintenance. The result from our kindness survey thus favors the explanation that the differences in cooperation attitudes across treatments are rooted in differences in the underlying preferences. 4. Step 2: perceptions of kindness in Maintenance and Provision A prominent psychological explanation for the existence of conditional cooperation is that individuals are reciprocal, that is, they have a desire to reward kind intentions with kindness and punish unkind intentions with unkindness (see Fehr and Schurtenberger, 2018 for a review). Hence, as reciprocity is the behavioral response to perceived kindness or unkind- ness (Rabin, 1993; Dufwenberg and Kirchsteiger, 2004; Falk and Fischbacher, 2006), a crucial question is how participants evaluate actions of others in terms of (un)kindness, and whether these evaluations differ across games. If people perceive payoff-equivalent actions differently in terms of kindness across Maintenance and Provision, this could trigger game-specific reciprocal responses which, in turn, could explain the observed differences in conditional cooperation across the two setups. p p p p p To test this conjecture, we conducted two online studies in which we elicited kindness perceptions about other people’s contribution behavior for both types of social dilemmas (see Falk and Fischbacher, 2006 for a related exercise and Wilson, 2012 for a cautionary note). In the questionnaire, we explained to participants either a Maintenance or a Provision dilemma and then asked them to evaluate the kindness of average effective contributions of three other group members on a scale from -100 to +100 (where -100 corresponds to ‘very unkind’ and +100 corresponds to ‘very kind’). We asked participants to evaluate the kindness of a low, an intermediate, and a high effective contribution of 0, 10, and 20, respectively (see Online Appendix A3). We recruited n = 185 students from the University of Nottingham and n = 401 participants from MTurk. No participant was involved in any of our experimental sessions before.16 Fig. 3 reports the average kindness evaluation of others’ average effective contributions. The results from the two samples are remarkably similar. While low effective contributions of 0 are considered as significantly less kind in Provision than in Maintenance (two-sided t-tests, p < 0.001 and p < 0.001 for students and MTurkers, respectively), we observe the reverse 345 S. Gächter, F. Kölle and S. Quercia Games and Economic Behavior 135 (2022) 338–355 pattern for medium and high effective contributions of 10 and 20, respectively. 5. Step 3: measuring and controlling for game form misperceptions One alternative explanation for our results is that participants may have systematic misperceptions of the game form and that these misperceptions may be dilemma specific. If this were the case, differences in conditional cooperation may not be due to different social preferences but due to differences in the understanding of the incentives of the game. In this section, we assess to what extent game-form misperceptions can explain our results. Table 2 i i Table 2 Table 2 Incentivized misperception questions and percentage of correct answers across Maintenance (M, n = 320) and Provision (P, n = 376). % Correct answers M P χ 2 – test Payoff questions: Q1: Assume that you contribute 20 tokens to the project and the other three group members contribute nothing to the project. What will your total income be? 95.3 95.5 p = 0.917(q = 0.917) Q2: Assume that you contribute 20 tokens to the project and the other three group members contribute nothing to the project. What will the total income of each of the other group members be? 90.9 84.3 p = 0.009 (q = 0.035) Q3: Assume that you contribute 0 tokens to the project and each of the other three group members contributes 20 tokens to the project. What will your total income be? 94.4 92.8 p = 0.405 (q = 0.649) Q4: Assume that you contribute 0 tokens to the project and each of the other three group members contributes 20 tokens to the project. What will the total income of each of the other group members be? 95.9 93.1 p = 0.103 (q = 0.275) Goal questions: Q5: Suppose the other group members contribute on average 0 tokens to the project. How much should a person who wants to make as much money as possible for him/herself contribute to the project? 92.8 95.0 p = 0.239 (q = 0.478) Q6: Suppose the other group members contribute on average 20 tokens to the project. How much should a person who wants to make as much money as possible for him/herself contribute to the project? 93.8 85.6 p = 0.001 (q = 0.004) Q7: Suppose the other group members contribute on average 0 tokens to the project. How much should a person who wants that the group as a whole makes as much money as possible contribute to the project? 79.1 77.1 p = 0.539 (q = 0.664) Q8: Suppose the other group members contribute on average 20 tokens to the project. How much should a person who wants that the group as a whole makes as much money as possible contribute to the project? 93.1 92.0 p = 0.581 (q = 0.664) Total 91.9 89.4 p = 0.030 Notes: Shown are the questions in Provision. The questions for Maintenance were formulated equivalently. Payoff questions: Notes: Shown are the questions in Provision. The questions for Maintenance were formulated equivalently. q-values correspond to p-values corrected for multiple comparisons using the Benjamini and Hochberg (1995) false discovery rate procedure. For testing the total effect (last row) we use logistic regressions with standard errors clustered at the individual level. correct answer.17 After that, the experiment proceeded with the elicitation of cooperation preferences using the strategy method. We asked the incentivized questions before we elicited participants’ preferences to ensure maximal understanding of the situation and incentives.18 correct answer.17 After that, the experiment proceeded with the elicitation of cooperation preferences using the strategy method. We asked the incentivized questions before we elicited participants’ preferences to ensure maximal understanding of the situation and incentives.18 The first four questions, which we label payoff questions, are akin to standard control questions in which participants have to calculate earnings for various contribution scenarios. We asked participants to determine their own and others’ monetary earnings in case (i) they would contribute their whole endowment, but the other group members would contribute nothing, and (ii) they would contribute nothing but each of the other group members would contribute their whole endowment (20 tokens) (see Q1 – Q4 in Table 2 for the exact wording of questions). Our first measure of game-form misperception classifies a participant as misperceiving if they make at least one mistake in the payoff questions (see Bartling et al., 2015 for a similar approach in a value elicitation task). In the other four questions (compare Q5 – Q8 in Table 2), which we label goal questions, we follow a similar strategy as Fosgaard et al. (2017) and ask participants what a person who wants to implement a specific goal should do. The first goal was individual payoff maximization; participants were asked how much a person who “wants to make as much money as possible for him/herself” should contribute given the other group members contribute either 0 or 20. The second goal was group payoff maximization: we asked participants how much a person who “wants that the group as a whole makes as much money as possible” should contribute given the other group members contribute either 0 or 20. We classify a participant as misperceiving if they make at least one mistake in the goal questions. This constitutes our second measure of game-form misperception. 18 In this methodological aspect, our approach is akin to Plott and Zeiler (2005) who used a battery of experimental tools designed to maximize under- standing before eliciting WTA-WTP valuations. Payoff questions: Compared to the payoff questions, which require an understanding of the incentive structure as well as sufficient calculation skills, the goal questions require the ability to put oneself into the shoes of another person that might have different objectives than oneself, a task that is arguably more difficult than just calculating payoffs. Finally, our third measure checks whether a participant is a mistaken conditional cooperator, that is, whether they think that maximizing their own income requires increasing own contribution if others’ contributions increase (from 0 to 20), that is if their response to Q6 is strictly higher than their response to Q5. Such a mistake could lead participants to believe that they face incentives akin to a coordination game rather than a social dilemma game. As a result, participants may then implement ‘wrong’ behavioral responses given their underlying preferences. That is, while the behavioral response of such a misperceiving participant in the strategy method might look like evidence of prosocial, reciprocal preferences, such behavior is also consistent with a model in which a purely selfish participant maximizes their misperceived payoffs. 5.3. Misperceptions are dilemma specific To avoid any income effects when eliciting cooperation preferences, incentives were modest, and participants were informed about the number of questions they answered correctly only at the very end of the experiment. 18 In this methodological aspect, our approach is akin to Plott and Zeiler (2005) who used a battery of experimental tools designed to maximize under- standing before eliciting WTA-WTP valuations. 17 To avoid any income effects when eliciting cooperation preferences, incentives were modest, and participants wer questions they answered correctly only at the very end of the experiment. Table 2 i i q-values correspond to p-values corrected for multiple comparisons using the Benjamini and Hochberg (1995) false discovery rate procedure. For testing the total effect (last row) we use logistic regressions with standard errors clustered at the individual level. 5.2. Measurement of game form misperceptions 5.2. Measurement of game form misperceptions We measure game-form misperceptions in a new experiment with n = 696 Nottingham students who had not partici- pated in any of our experiments before. The experiment followed the structure presented in Section 2, except that there was no direct-response experiment after the strategy-method experiment. Instead, after participants answered the standard set of ten control questions, we asked them two additional sets of four incentivized questions (see Table 2), paying £0.1 per 346 Games and Economic Behavior 135 (2022) 338–355 S. Gächter, F. Kölle and S. Quercia 5.4. Misperceptions and cooperation attitudes In the following, we analyze the connection between misperceptions and the elicited cooperation attitudes. If there was none, i.e., if mistakes were randomly distributed across types, then the different degrees in the level of misperception across Maintenance and Provision should not affect the distribution of types. If, instead, the likelihood of game-form misperception is correlated with displaying a certain cooperation type, this could explain the differences in conditional cooperation we observed across our two treatments. Table 4 reports the fraction of misperceiving participants conditional on type classification. We report these numbers separately for Maintenance and Provision and our three measures of misperception. Table 4 reveals that the null hypothe- sis of no relationship between types and misperceptions can be rejected for both Maintenance and Provision according to Measure 2 (goal questions, χ 2 – tests, both p < 0.007) and Measure 3 (mistaken conditional cooperation, χ 2 – tests, both p < 0.003), but not for Measure 1 (payoff questions, χ 2 – tests, both p > 0.065). On top of that, our results reveal that the way misperceptions interact with the elicited attitudes is treatment-specific. In Maintenance we observe mainly the participants classified as others who display some form of misperceptions; compared to free riders their odds of displaying misperceptions (calculated as the ratio between misperceiving and non-misperceiving participants) are increased by a factor of 2.3 (Measure 1) up to 5.9 (Measure 3). In Provision, in contrast, we find that mainly the group of conditional cooperators exhibiting misperceptions; compared to free riders their odds of displaying misperceptions is increased by a factor of 1.6 (Measure 1) up to 8.3 (Measure 3). These results show that the two types of dilemmas not only affect the overall level of misperception but also how perceptions interfere with preferences. This provides a strong case for the need of controlling for misperceptions before in- terpreting behavioral differences as dilemma-dependent preferences. In the following, we therefore test whether accounting for the different types of misperceptions can explain the observed treatment differences in the distribution of cooperation preferences. We report this analysis in Table 5. Panel A of Table 5 shows the distribution of types in the full sample (without controlling for misperceptions). 19 The relative frequency of types is somewhat different compared to the one found in our initial student sample as reported in Section 3.1. Specifically, we find a significant change in the distribution of types in both Provision (χ2(2) = 14.26, p = 0.001) and Maintenance (χ2(2) = 11.01, p = 0.004), with more free riders (Provision: 27% vs. 17%, χ2(1) = 10.43, p = 0.001, Maintenance 39% vs. 28%, χ2(1) = 10.44, p = 0.001) and fewer conditional cooperators 5.3. Misperceptions are dilemma specific When comparing the fraction of correct answers between Maintenance and Provision for each question separately, we find significant differences for two out of the eight questions, Q2 (p = 0.009) and Q6 (p = 0.001). Next, we turn to an individual-level analysis of mistakes by applying our three measures of game-form misperceptions as described above. As shown in Table 3, for all measures, we find that misperceptions are significantly more frequent in Provision than in Maintenance; the number of people misperceiving is between 8 and 9 percentage points higher in Provision than in Maintenance (χ 2 – tests, all p < 0.023). (χ p ) We summarize these findings in our third result: Result 3: Provision dilemmas cause significantly higher levels of misperceptions of the game form tha 5.4. Misperceptions and cooperation attitudes 5.3. Misperceptions are dilemma specific Table 2 summarizes the percentages of correct answers separately for each question and for Maintenance and Provision. It reveals that, at the aggregate level, in both treatments there is an overall very low level of misperception. With a few 347 Games and Economic Behavior 135 (2022) 338–355 S. Gächter, F. Kölle and S. Quercia Table 3 Percent of participants classified as misperceiving in Maintenance and Provision. Maintenance [n = 320] Provision [n = 376] χ 2 - test Measure 1 – At least one mistake in the payoff questions Q1-Q4 13% [n = 40] 22% [n = 84] p = 0.001 Measure 2 – At least one mistake in the goal questions Q5-Q8 29% [n = 93] 37% [n = 140] p = 0.023 Measure 3 – Mistaken conditional cooperation 5% [n = 17] 13% [n = 47] p = 0.001 Table 4 Fraction of misperceiving participants in Maintenance and Provision by type. Maintenance Provision Measure 1 Measure 2 Measure 3 Measure 1 Measure 2 Measure 3 Conditional Cooperators 0.103 0.252 0.028 0.247 0.447 0.200 Free Riders 0.095 0.230 0.024 0.165 0.262 0.029 Others 0.195 0.425 0.126 0.241 0.337 0.072 χ 2 - tests p = 0.066 p = 0.005 p = 0.002 p = 0.247 p = 0.006 p < 0.001 Table 4 Fraction of misperceiving participants in Maintenance and Provision by type. exceptions, the percentage of correct answers is above 90% for every single question and treatment. On average, participants answer 91% of the questions correctly, 92% in Maintenance (7.35 out of 8) and 89% in Provision (7.15 out of 8). Despite the overall treatment differences being small, they are statistically significant at the 5% level (p = 0.030). When comparing the fraction of correct answers between Maintenance and Provision for each question separately, we find significant differences for two out of the eight questions, Q2 (p = 0.009) and Q6 (p = 0.001). exceptions, the percentage of correct answers is above 90% for every single question and treatment. On average, participants answer 91% of the questions correctly, 92% in Maintenance (7.35 out of 8) and 89% in Provision (7.15 out of 8). Despite the overall treatment differences being small, they are statistically significant at the 5% level (p = 0.030). Table 5 Table 5 Distribution of cooperation preferences in Maintenance and Provision after controlling for different types of misperceptions. Panel A: Full sample Panel B: No mistake in payoff questions Type Maintenance (n = 320) Provision (n = 376) χ 2-test Maintenance (n = 280) Provision (n = 292) χ 2-test Conditional Cooperators 34% 51% p < 0.001 34% 49% p < 0.001 Free Riders 39% 27% p = 0.001 41% 29% p = 0.005 Others 27% 22% p = 0.118 25% 22% p = 0.332 χ 2-test p < 0.001 p = 0.001 Panel C: No mistake in goal questions Panel D: No mistaken conditional cooperation Type Maintenance (n = 227) Provision (n = 236) χ 2-test Maintenance (n = 303) Provision (n = 329) χ 2-test Conditional Cooperators 35% 45% p = 0.042 34% 46% p = 0.002 Free Riders 43% 32% p = 0.019 41% 31% p = 0.007 Others 22% 23% p = 0.743 25% 23% p = 0.623 χ 2-test p = 0.050 p = 0.006 ation preferences in Maintenance and Provision after controlling for different types of misperceptions. In panels B, C, and D, we compare the distribution of types across Maintenance and Provision after dropping participants who are classified as misperceiving according to Measures 1, 2, and 3, respectively. The results reveal that our main result of different distributions of cooperation preferences across Maintenance and Provision is robust to the exclusion of participants who do not fully understand the game form. That is, the distribution of types is significantly different across Maintenance and Provision across all subsamples of non-confused participants (χ 2 – tests, all p ≤0.05). χ Regarding the distribution of types, we observe significantly more conditional cooperators (χ 2 – tests, all p < 0.05) and significantly fewer free riders (χ 2 – tests, all p < 0.02) in Provision than in Maintenance (the difference in others is never significant, χ 2 – tests, all p > 0.117; see also Table B7 in Online Appendix B). Notably, however, we find that once we control for misperceptions, the differences in the distribution of types become smaller compared to the full sample. The percentage difference in conditional cooperators decreases from 17 percentage points in the full sample to 10 to 15 percentage points depending on the misperception measure. (Provision: 63% vs. 51%, χ2(1) = 12.50, p < 0.001, Maintenance 33% vs. 43%, χ2(1) = 5.84, p = 0.016) in the new experiment. We believe that the reason for this result is that we administered the incentivized control questions before the elicitation of cooperation attitudes. This might have made the incentive structure of the social dilemma situation even clearer, which, in turn, might have corrected some ‘mistaken’ conditional cooperation. Alternatively, it could be that the incentivized questions increased the salience of material incentives, thereby priming participants to be more self-interested. While we cannot rule out neither of these channels, we can ascertain whether the shifts in the distribution of types had any effect on the differences across treatments. To this end, similar to our analysis in which we compared our student with the MTurk sample, we run logistic regressions in which we use the different types as dependent variable, a treatment dummy, a sample dummy, and an interaction between the latter two as independent variables. The results, reported in Table B6 in Online Appendix B, show that there are no significant interaction effects between the treatment and the sample, indicating that adding the additional questions at the beginning of the experiment had no systematic effect on our treatment comparison. Table 5 The difference in the fraction of free riders, in contrast, remains stable, varying between 10 and 12 percentage points. This demonstrates that while misperceptions can account for some of the observed differences across treatments, even after controlling for misperceptions, we observe substantial and significantly different degrees of conditional cooperation in Maintenance and Provision. We summarize these findings in our fourth result: g p g Result 4: Even after accounting for the different degrees of misperceptions across Maintenance and Provision, we find significantly more conditional cooperators and fewer free riders in Provision than in Maintenance. 5.5. Misperceptions do not affect perceptions of kindness 5.4. Misperceptions and cooperation attitudes In line with our results from Section 3, we find again a highly significant difference in the distribution of preferences across treatments (χ 2(2) = 21.23, p < 0.001), with significantly fewer conditional cooperators (χ 2(1) = 20.65, p < 0.001) and significantly more free riders (χ 2(1) = 11.24, p = 0.001) in Maintenance than in Provision.19 348 Games and Economic Behavior 135 (2022) 338–355 S. Gächter, F. Kölle and S. Quercia 5.5. Misperceptions do not affect perceptions of kindness The results above already strongly suggest that the observed differences in cooperation types across Maintenance and Provision are rooted in differences in the underlying social preferences. As we have argued above, these differences can be explained by differences in the perceived kindness of others’ actions across the two treatments. As a final test of this argu- ment, we provide evidence that the different perceptions of kindness that we presented in Section 4 are not a consequence of game-form misperceptions. This is important because if differences in kindness perceptions are indeed the main trigger of differences in conditional cooperation across the two social dilemmas, we should observe that perceptions of kindness still differ when controlling for misperceptions. If, instead, the different kindness perceptions across Maintenance and Provi- sion disappear when controlling for misperceptions, then the elicited kindness perceptions may not be considered a relevant explanation for the differences in conditional cooperation across the two dilemmas. To test this, in some sessions of the misperception experiment reported in the previous two subsections, we included the kindness questionnaire at the end of the experiment before participants received feedback about the outcome of the game. Hence, while the kindness results reported in Section 4 (see Fig. 3) were elicited using non-involved participants, we can now test whether the results hold when participants have experienced the decision situation. Furthermore, we can test whether the differences in kindness perceptions across Maintenance and Provision are robust to the exclusions of participants who exhibit some misperception. Our sample comprises n = 200 participants, n = 80 in Maintenance and n = 120 in Provision. The results are shown in Fig. 4. 349 Games and Economic Behavior 135 (2022) 338–355 S. Gächter, F. Kölle and S. Quercia Fig. 4. Kindness perceptions in Provision and Maintenance of participants who experienced the decision situation (±1 s.e.m). Fig. 4. Kindness perceptions in Provision and Maintenance of participants who experienced the decision situation (±1 s.e.m). The first (upper left) panel of Fig. 4 depicts the comparison between the kindness schedules between Maintenance and Provision for the full sample. The second, third, and fourth panel show the same data for the subset of participants without misperceptions according to our three measures. Fig. 4 shows that the differences in kindness schedules across Maintenance and Provision are not only similar across the four panels but also similar to the ones reported in Fig. 3. 20 Parametric estimates further corroborate these results. Using regression analyses in which we regress kindness evaluations on others’ average contri- butions, a Provision dummy, and an interaction term between the last two, we find that the Provision dummy is significantly negative and the interaction term between the Provision dummy and others’ average contributions is positive and significant. The size of these effects, which we report in Table B8 in Online Appendix B, is similar to the ones reported in Section 4 where we analyze the kindness evaluations of uninvolved participants (compare also Table B5). 5.5. Misperceptions do not affect perceptions of kindness This indicates that the differences in kindness perceptions across Maintenance and Provision are robust to having experienced the decision situation beforehand and, more importantly, to the exclusion of participants who exhibit some form of game-form misperception.20 We summarize these findings in our fifth result: We summarize these findings in our fifth result: Result 5: Even after accounting for the different degrees of misperceptions across Maintenance and Provision, we find that the two dilemmas evoke systematically different perceptions of kindness that can explain why there are more conditional cooperators and fewer free riders in Provision than in Maintenance. 6.1. Explaining dilemma-specific conditional cooperation 6.1. Explaining dilemma-specific conditional cooperation We start our discussion with theories of distributional preferences (Fehr and Schmidt, 1999; Bolton and Ockenfels, 2000; Charness and Rabin, 2002). While all these theories can explain conditional cooperation, e.g., if advantageous inequity aversion is strong enough, they do not predict any dilemma-specific conditional cooperation. The reason is that these the- ories are only based on payoff consequences, which are identical across the two incentive-equivalent social dilemmas of Maintenance and Provision.21 Note that this prediction hinges on the original assumption of these theories that individual preference parameters are game-independent. If one would be willing to relax this assumption by allowing preference pa- rameters to differ across contexts, then these models could potentially rationalize our findings. For example, if one assumes, using Fehr and Schmidt (1999) preferences, that agents are more advantageous inequity-averse when facing a Provision rather than a Maintenance dilemma, then this could explain why we observe more conditional cooperators and fewer free riders in the former than in the latter. We note, however, that while such shifts in advantageous inequity aversion might be empirically relevant, there is no psychological mechanism in the formal assumptions of Fehr and Schmidt (1999) that postulate such shifts. Next, we consider theories of reciprocity (Rabin, 1993; Dufwenberg and Kirchsteiger, 2004; Falk and Fischbacher, 2006), in which agents’ motivations derive from their material payoff as well as a psychological payoff that depends on their first-order beliefs about others’ actions. These theories can also explain conditional cooperation (Dufwenberg et al., 2011) because agents want to reward kind actions with kindness and punish hostile actions with unkindness. Kindness is thereby assumed to be evaluated relative to a reference point that is the midpoint between the maximum and minimum possible payoff (see Online Appendix C, and Dufwenberg and Kirchsteiger, 2019 for a recent discussion). Because the payoff sets are the same in Maintenance and Provision, the reference point must be the same. Therefore, beliefs are the only channel through which simultaneous gameplay may differ in Maintenance and Provision. Since in our strategy-method experiment (i) first-order beliefs are fixed because participants condition their contributions on all possible average contributions of others, and (ii) as argued by Dufwenberg et al. (2011), in a linear public goods game the evaluation of others’ kindness only depends on first-order beliefs, these models do not predict dilemma-dependent conditional cooperation. 6.1. Explaining dilemma-specific conditional cooperation This prediction also hinges on the assumption that the concern for reciprocity as measured by a reciprocity parameter does not vary across dilemmas. If one would be willing to relax this assumption to allow that the reciprocity parameter is stronger under Provision than Maintenance, then reciprocity theory could also rationalize our finding that conditional cooperation is more frequent in Provision than Maintenance. Note, however, that also in this theory there is no psychological mechanism in the formal assumptions that postulates such a shift. The next theory we discuss is guilt aversion. We rely on a model of guilt by Battigalli and Dufwenberg (2007) that assumes that an agent’s utility depends on her material payoff as well as her second-order beliefs, that is, what she believes the other players believe she will do. Applied to the context of a public goods game (see also Dufwenberg et al., 2011), guilt aversion predicts that player i will suffer guilt if i contributes less than what i thinks the other three group members expect i to contribute (on average). If the disutility from guilt becomes large enough, player i has an incentive to contribute whatever she thinks others expect her to contribute (that is, her second-order beliefs). Given that in our strategy-method experiment first-order beliefs are fixed, differences in cooperation attitudes could be reconciled via dilemma-dependent second-order beliefs: If more participants in Provision than in Maintenance would have second-order beliefs that others expect them to reciprocate their contributions, the perceived guilt from not matching others’ contributions would be stronger, which, in turn, could lead to a higher fraction of conditional cooperators in Provision than in Maintenance. However, guilt aversion theory does not explicitly model any mechanism for why there should be any difference in second-order beliefs between Maintenance and Provision. Similarly, the guilt-sensitivity parameter is also assumed to be the same across dilemmas and there is no psychological mechanism in the formal assumptions that would suggest dilemma-specific guilt sensitivity.22 In sum, all standard theories of social preferences discussed so far can explain conditional cooperation. However, to be able to explain dilemma-specific conditional cooperation they all require some adjustments not present in the original formulations of these theories, such as modeling mechanisms of dilemma-dependent beliefs or preference parameters. One theory that has the potential to predict a difference between Maintenance and Provision is revealed altruism by Cox et al. (2008). 6. Step 4: which theory of social preferences can explain our results? In our fourth step, we investigate which of the existing models of social preferences, using their original formulations, can reconcile the observation of a higher share of conditional cooperators and fewer free riders in Provision than in Maintenance as found in our experiments as well as in some previous research (Fosgaard et al., 2014; Frackenpohl et al., 2016; Gächter et al., 2017; Isler et al., 2021). We emphasize that our aim here is not to conduct a horse race between different models of social preferences (see, e.g., Miettinen et al., 2020, for such an analysis in a sequential PD), but to provide a discussion about whether, and under which assumptions, existing theories of social preferences can explain dilemma-dependent conditional cooperation (note that all theories we discuss here can explain conditional cooperation in a given social dilemma). In the following, we only describe the main arguments, more details and formal analyses are in Online Appendix C. In Section 6.1., we discuss how theories of social preferences might explain dilemma-specific conditional cooperation. In Section 6.2., we discuss the models also in relation to our results on kindness perceptions (Results 2 and 5). 350 Games and Economic Behavior 135 (2022) 338–355 Games and Economic Behavior 135 (2022) 338–355 S. Gächter, F. Kölle and S. Quercia A similar argument holds for models of altruism and fairness such as Levine (1998) and Cox et al. (2007). 22 Evidence from two online surveys in which we elicited ex post feelings of guilt further reveal that participants do not feel more guilty when free riding on others’ contributions in Provision than in Maintenance, indicating that ex post feelings of guilt cannot explain the observed differences in conditional cooperation across the two dilemmas (see Online Appendix D for further details). 21 A similar argument holds for models of altruism and fairness such as Levine (1998) and Cox et al. (2007). Evidence from two online surveys in which we elicited ex post feelings of guilt further reveal that participants do n on others’ contributions in Provision than in Maintenance, indicating that ex post feelings of guilt cannot explain the cooperation across the two dilemmas (see Online Appendix D for further details). 6.1. Explaining dilemma-specific conditional cooperation This theory is governed by two axioms, the reciprocity Axiom R, and Axiom S, which allows for status quo effects. Applying Cox et al.’s Axiom R to our public goods games, the model predicts that participants will perceive higher contributions by the other group members as more generous towards them, and, therefore, they will be more altruistic towards the others. In our strategy-method experiment, this will be manifested in a positive slope of the contribution schedule (see Cox et al., 2013 for a related analysis). In Axiom S, Cox et al. (2008) assume that, based on the psychological asymmetry behind omission and commission (see, e.g., Spranca et al., 1991), generous actions that change the status quo trigger stronger reciprocity than generous actions that just uphold the status quo. That is, Axiom S strengthens or weakens the effect of Axiom R depending on the status quo. If one assumes that players perceive the original allocation to the public good before decision making (0 in Provision and 351 S. Gächter, F. Kölle and S. Quercia Games and Economic Behavior 135 (2022) 338–355 80 in Maintenance) as the status quo (as in Cox et al., 2013), then, applying Axiom S to our strategy-method experiment, the theory predicts that second movers will be less altruistic towards first movers in Maintenance than in Provision. The reason is that in Provision any positive contribution by the other three group members increases the payoff opportunities of the second mover compared to the status quo where nothing is contributed to the public good. In Maintenance, in contrast, where all resources are initially allocated to the public good, any withdrawal by the other three group members reduces the payoff opportunities for the second mover. This asymmetry triggers a stronger preference for reciprocity in Provision than Maintenance, which can explain our finding of more conditional cooperators and fewer free riders in Provision than in Maintenance (see Online Appendix C for further details).23 80 in Maintenance) as the status quo (as in Cox et al., 2013), then, applying Axiom S to our strategy-method experiment, the theory predicts that second movers will be less altruistic towards first movers in Maintenance than in Provision. The reason is that in Provision any positive contribution by the other three group members increases the payoff opportunities of the second mover compared to the status quo where nothing is contributed to the public good. 23 Here we have assumed that, as in Cox et al. (2013), the initial resource allocation is taken as the status quo. We acknowledge, however, that different assumptions on the status quo could be plausible. For example, the status quo could be the wealth level of participants before entering the lab. In this case, the Cox et al. (2008) theory would predict no differences between Maintenance and Provision. 24 Formally, Axiom S would need to be modified to allow the status quo allocation to affect not only the MAT (more altruistic than) partial ordering but also the MGT (more generous than) partial ordering (see Online Appendix C for further details). 6.2. Explaining dilemma-specific kindness perceptions As a next step, we discuss which of the above theories can reconcile the robust and replicable evidence on different perceptions of kindness between Maintenance and Provision (Results 2 and 5). First, notice that models of distributional preferences are only based on payoff consequences and therefore do not incorporate any evaluation of others’ actions. Guilt aversion is also mute with respect to others’ kindness as players evaluate their own action with respect to the distance from their second-order belief but make no evaluation about others’ actions. Reciprocity models such as those by Dufwenberg and Kirchsteiger (2004) and Falk and Fischbacher (2006) are natural candidates to explain our kindness results: these theories incorporate the perception of other’s (un)kindness as a central element into their models and the positive and negative kindness evaluations we observe are consistent with typical modeling assumptions. In these models, kindness is evaluated with respect to a reference point that is only based on material payoffs. Because material payoffs are identical in Maintenance and Provision, for a given effective contribution perceived kindness is predicted to be the same across Maintenance and Provision. Finally, we consider the revealed altruism model by Cox et al. (2008) that also incorporates kindness. However, like the reciprocity models, this model also does not predict any differences in kindness perceptions across the dilemmas. Instead, it postulates that the different status-quo allocation in Maintenance and Provision directly affect the reciprocity parameter (see Axiom S). If one would be willing to adjust the model by allowing Axiom S to also affect perceptions of kindness, then every effective contribution in Provision should be perceived as more generous than the corresponding effective contribution in Maintenance.24 The results from our kindness survey reveal, however, that while this is indeed true for average effective contributions of 10 and 20, for effective contributions of 0 we find the opposite as contributing 0 in Provision is perceived as unkinder than withdrawing everything in Maintenance. Hence, although Cox et al. (2008) comes closest to explaining our results as it is the only theory that postulates an explicit mechanism for why one could expect stronger conditional cooperation in Provision than in Maintenance, some discrepancies between the theory and our data remain as we have seen in our results on kindness perceptions (Results 2 and 5). 6.1. Explaining dilemma-specific conditional cooperation In Maintenance, in contrast, where all resources are initially allocated to the public good, any withdrawal by the other three group members reduces the payoff opportunities for the second mover. This asymmetry triggers a stronger preference for reciprocity in Provision than Maintenance, which can explain our finding of more conditional cooperators and fewer free riders in Provision than in Maintenance (see Online Appendix C for further details).23 7. Discussion and conclusion In this paper, we provided a comprehensive behavioral analysis of two generic and incentive-equivalent social dilemmas of voluntary cooperation: providing and maintaining public goods. We first established a lower fraction of conditional co- operators (and higher fraction of free riders) in Maintenance than Provision (Result 1). We then focused on two fundamental dimensions: social preferences and (mis)perceptions of others’ intentions and the game form. We reported two important asymmetries. First, regarding perceptions, we found that perceptions of the kindness of others’ actions differ between Main- tenance and Provision because withdrawing everything from the public good is seen as less unkind than failing to contribute to the public good; and contributing everything is considered kinder in Provision than in Maintenance (Result 2). Regard- ing perceptions of the game form, we found that misperceptions are game-specific: misunderstandings are more likely in Provision than Maintenance (Result 3). Second, even after controlling for misperceptions, we observe substantial and signifi- cantly different degrees of conditional cooperation in Maintenance and Provision (Result 4); perceptions of kindness remain unaffected by misperceptions (Result 5). Hence, conditional cooperation is not just mistaken cooperation (as argued, e.g., by Burton-Chellew et al., 2016), but a true preference that is less frequently found in Maintenance than in Provision dilemmas. ) p q y Our Result 4 somewhat differs from the results by Fosgaard et al. (2017). Like them, we find that the differences in conditional cooperation across dilemmas become smaller once accounting for misperceptions. Unlike us, in their case the differences become statistically insignificant while in ours they remain economically and statistically significant. One pos- sible explanation for the different findings is that Fosgaard et al. (2017) asked their misperception questions, which are similar to our Measure 2, only at the end of the experiment rather than before the elicitation of cooperation preferences as we do. Another reason could be the different subject pools used across the two studies – our results are based on a UK student sample while theirs is based on a representative sample of the Danish population – which could also explain why 352 S. Gächter, F. Kölle and S. Quercia Games and Economic Behavior 135 (2022) 338–355 the overall level of misperceptions is much higher in Fosgaard et al.: In their sample, 41% and 51% of participants exhibit some form of misperception in Maintenance and Provision, respectively, compared to 29% and 37% in our case. Data availability The data and analysis code of this paper are available at https://osf .io /3jpgh/ Acknowledgments This work was supported by the European Research Council [grant numbers ERC-AdG 295707 COOPERATION and ERC- AdG 101020453 PRINCIPLES] and the Economic and Social Research Council [grant number ES/K002201/1]. The research reported in this paper was approved by the Research Ethics Committee of the Nottingham School of Economics. The au- thors declare they have no relevant or material financial interests that relate to the research described in this paper. We thank Ben Beranek for excellent research support and Abigail Barr, Tim Cason, Gary Charness, Jim Cox, Robin Cubitt, Mar- tin Dufwenberg, Urs Fischbacher, Maria Garcia-Vega, Werner Güth, Georg Kirchsteiger, Friederike Mengel, Charles Noussair, Elena Manzoni, Vjollca Sadiraj, Maroš Servátka, Chris Starmer, Robert Sugden, and referees and participants from various seminars and conferences for helpful comments. 7. Discussion and conclusion Our finding that kindness perceptions remain different across dilemmas also after removing misperceiving subjects reinforces further a preference explanation for the difference between Maintenance and Provision. Our Results 1 – 5 also suggest an important general lesson: the revealed preference approach, that is, using choices to infer social preferences and/or dilemma-specific effects, requires controlling for perceptions.25 This includes potential misperceptions of the game form to ensure measurement of preferences over clearly understood alternatives. Administering simple understanding questions at the beginning of experiments is nowadays quite common in experimental economics. However, it might not be enough. Our evidence on the existence of misperceived conditional cooperation is a point in case. Our results also have implications for future literature. Hitherto, behavioral investigations of public goods provision and common pool resource problems have largely been conducted in independent literatures, in particular regarding conditional cooperation, which was mostly studied in the context of linear public goods provision games (see, e.g., Chaudhuri, 2011; Fehr and Schurtenberger, 2018; and Thöni and Volk, 2018). Our comparative analysis of preferences and perceptions in maintenance and provision problems with identical social dilemma incentives is only a first step in bringing these two literatures closer together. Finally, our results are not only of theoretical significance but have some potential policy implications. If many people are conditional cooperators, any factor that shifts beliefs about others’ cooperativeness will shift cooperation – a fact that can be used for policy interventions (e.g., Gächter, 2007). The observation that conditional cooperation, even after being corrected for misperceptions, is weaker in Maintenance than Provision suggests that policy proposals that reckon with conditional cooperation (e.g., MacKay et al., 2015) need to take into account that the extent of it is dilemma-specific. Some of the pressing challenges for mankind such as global warming and sustaining natural resources and biodiversity concern mainly Maintenance dilemmas (e.g., Fehr-Duda and Fehr, 2016). Our results suggest that the power of conditional cooperation may be limited in maintenance problems, at least in comparison with provision dilemmas. Other solutions such as punishment (Gächter et al., 2017; Ramalingam et al., 2019) or incentives may instead be needed. Supplementary material related to this article can be found online at https://doi .org /10 .1016 /j .geb .2022 .06 .009. Supplementary material related to this article can be found online at https://doi .org /10 .1016 /j .geb .2022 .06 .009. 25 Alternatively, when it is not possible to measure misperceptions directly (e.g., in representative surveys), econometric techniques such as those proposed by Goldin and Reck (2020) can be applied to correct for potential measurement error ex post. Alpizar, F., Carlsson, F., Johansson-Stenman, O., 2008. Anonymity, reciprocity, and conformity: evidence from voluntary contributions to a national park in Costa Rica. J. Public Econ. 92, 1047–1060. Andreoni, J., 1995a. Cooperation in public-goods experiments - kindness or confusion? Am. Econ. Rev. 85, 891–904. Andreoni, J., 1995b. Warm glow versus cold prickle - the effects of positive and negative framing on cooperation in experiments. Q. J. Econ. 110, 1–21. Apesteguía, J., Maier-Rigaud, F.P., 2006. The role of rivalry. Public goods versus common-pool resources. J. Confl. Resolut. 50, 646–663. Arechar, A.A., Gächter, S., Molleman, L., 2018. Conducting interactive experiments online. Exp. Econ. 21, 99–131. Bardsley, N., 2008. Altruism or artefact? A note on dictator game giving. Exp. Econ. 11, 122–133. Bartling, B., Engl, F., Weber, R.A., 2015. Game form misconceptions are not necessary for a willingness-to-pay vs. willingness-to-accept gap. J. Econ. Sci. Assoc. 1, 72–85. Bartling, B., Fehr, E., Özdemir, Y., 2021. Does market interaction erode moral values? Rev. Econ. Stat., 1–32. Battigalli, P., Dufwenberg, M., 2007. Guilt in games. Am. Econ. Rev. 97, 170–176. Bayer, R.-C., Renner, E., Sausgruber, R., 2013. Confusion and learning in the voluntary contributions game. Exp. Econ. 16, 478–496. Becker, G.M., DeGroot, M.H., Marschak, J., 1964. Measuring utility by a single-response sequential method. Behav. Sci. 9, 226–232. Benjamini, Y., Hochberg, Y., 1995. Controlling the false discovery rate: a practical and powerful approach to multiple testing. J. R. Stat. Soc. B 57, 289–300. Games and Economic Behavior 135 (2022) 338–355 Social framing effects: preferences or beliefs? Games Econ. Behav. 76, 117–130. Falk, A., Fischbacher, U., 2006. A theory of reciprocity. Games Econ. Behav. 54, 293–315. llingsen, T., Johannesson, M., Mollerstrom, J., Munkhammar, S., 2012. Social framing effects: preferences or beliefs? Games E alk, A., Fischbacher, U., 2006. A theory of reciprocity. Games Econ. Behav. 54, 293–315. Faul, F., Erdfelder, E., Lang, A.-G., Buchner, A., 2007. G*Power 3: a flexible statistical power analysis program for the social, behavioral, and biomedical sciences. Behav. Res. Methods, 1–17. Fehr, E., Leibbrandt, A., 2011. A field study on cooperativeness and impatience in the Tragedy of the Commons. J. Public Econ. 95, 1144–1155. Fehr, E., Schmidt, K.M., 1999. A theory of fairness, competition, and cooperation. Q. J. Econ. 114, 817–868. ehr, E., Schurtenberger, I., 2018. Normative foundations of human cooperation. Nat. Hum. Behav. 2, 458–468. h d h 2016 G h fidi d l d i d d ll Fehr-Duda, H., Fehr, E., 2016. Game human nature: finding ways to adapt natural tendencies and nudge collective action is central to the wel future generations. Nature 530, 413–416. J., Vossler, C.A., 2010. The source and significance of confusion in public goods experiments. B.E. J. Econ. Anal. Policy 10, 1–4 er, U., 2007. z-Tree: Zurich toolbox for readymade economic experiments. Exp. Econ. 10, 171–178. Fischbacher, U., Gächter, S., 2010. Social preferences, beliefs, and the dynamics of free riding in public good experiments. Am. Econ. Rev. 100, 541–556. Fischbacher, U., Gächter, S., Fehr, E., 2001. Are people conditionally cooperative? Evidence from a public goods experiment. Econ. Lett. 71, 397–404. bacher, U., Gächter, S., Quercia, S., 2012. The behavioral validity of the strategy method in public good experiments. J. Econ. ard, T.R., Hansen, L.G., Wengström, E., 2014. Understanding the nature of cooperation variability. J. Public Econ. 120, 134–14 Fischbacher, U., Gächter, S., Quercia, S., 2012. The behavioral validity of the strategy method in public good experiments. J. Econ. Psychol. 33, 897–913. Fosgaard, T.R., Hansen, L.G., Wengström, E., 2014. Understanding the nature of cooperation variability. J. Public Econ. 120, 134–143. g , , , , g , , g p y J , osgaard, T.R., Hansen, L.G., Wengström, E., 2017. Framing and misperception in public good experiments. Scand. J. Econ. 119 rackenpohl, G., Hillenbrand, A., Kube, S., 2016. Leadership effectiveness and institutional frames. Exp. Econ. 19, 842–863. Frey, B.S., Meier, S., 2004. Social comparisons and pro-social behavior. Games and Economic Behavior 135 (2022) 338–355 Cox, J.C., Friedman, D., Sadiraj, V., 2008. Revealed altruism. Econometrica 76, 31–69. Cox, J.C., Ostrom, E., Sadiraj, V., Walker, J.M., 2013. Provision versus appropriation in symmetric and asymmetric social dilemmas. South. Econ. J. 79, 496–512. Cubitt, R., Drouvelis, M., Gächter, S., 2011a. Framing and free riding: emotional responses and punishment in social dilemma games. Exp. Econ. 14, 254–272. Cubitt R Drouvelis M Gächter S Kabalin R 2011b Moral judgments in social dilemmas: how bad is free riding? J Public Econ 95 253 264 ox, J.C., Ostrom, E., Sadiraj, V., Walker, J.M., 2013. Provision versus appropriation in symmetric and asymmetric social dilemma ubitt, R., Drouvelis, M., Gächter, S., 2011a. Framing and free riding: emotional responses and punishment in social dilemma g Cox, J.C., Ostrom, E., Sadiraj, V., Walker, J.M., 2013. Provision versus appropriation in symmetric and asymmetric social dilemmas. South. Econ. J. 79, 496–512. Cubitt, R., Drouvelis, M., Gächter, S., 2011a. Framing and free riding: emotional responses and punishment in social dilemma games. Exp. Econ. 14, 254–272. b l h b l b l d l d l h b d f d bl g g p p g t, R., Drouvelis, M., Gächter, S., Kabalin, R., 2011b. Moral judgments in social dilemmas: how bad is free riding? J. Public Eco Dal Bó, P., Fréchette, G.R., 2018. On the determinants of cooperation in infinitely repeated games: a survey. J. Econ. Lit. 56, 60–114. Dawes, R.M., 1980. Social dilemmas. Annu. Rev. Psychol. 31, 169–193. Dal Bó, P., Fréchette, G.R., 2018. On the determinants of cooperation in infinitely repeated games: a survey. J. Econ. Lit. 56, 60–114. Dawes, R.M., 1980. Social dilemmas. Annu. Rev. Psychol. 31, 169–193. C.K.W., McCusker, C., 1997. Gain–loss frames and cooperation in two-person social dilemmas: a transformational analysis. J. –1106. Drazen, A., Dreber, A., Ozbay, E.Y., Snowberg, E., 2021. Journal-based replication of experiments: an application to “Being chosen to lead”. J. Public Econ. 202, 104482. Dreber, A., Ellingsen, T., Johannesson, M., Rand, D., 2013. Do people care about social context? Framing effects in dictator games. Exp. Econ. 16, 349–371. Dufwenberg, M., Gächter, S., Hennig-Schmidt, H., 2011. The framing of games and the psychology of play. Games Econ. Behav. 73, 459–478. Dufwenberg, M., Kirchsteiger, G., 2019. Modelling kindness. J. Econ. Behav. Organ. 167, 228–234. Dufwenberg, M., Kirchsteiger, G., 2019. Modelling kindness. J. Econ. Behav. Organ. 167, 228 234. Ellingsen, T., Johannesson, M., Mollerstrom, J., Munkhammar, S., 2012. Levin, S.A., 2014. Public goods in relation to competition, cooperation, and spite. Proc. Natl. Acad. Sci. 111, 10838–10845. Levine, D.K., 1998. Modeling altruism and spitefulness in experiments. Rev. Econ. Dyn. 1, 593–622. List, J.A., 2007. On the interpretation of giving in dictator games. J. Polit. Econ. 115, 482–493. Games and Economic Behavior 135 (2022) 338–355 Games and Economic Behavior 135 (2022) 338–355 S. Gächter, F. Kölle and S. Quercia Bicchieri, C., Dimant, E., Gächter, S., Nosenzo, D., 2022. Social proximity and the erosion of norm compliance. Games Econ. Behav. 132, 59–72. Bolton, G.E., Ockenfels, A., 2000. ERC: a theory of equity, reciprocity, and competition. Am. Econ. Rev. 90, 166–193. Bicchieri, C., Dimant, E., Gächter, S., Nosenzo, D., 2022. Social proximity and the erosion of norm compliance. Games Econ. Behav. 132, 59–72. Bolton, G.E., Ockenfels, A., 2000. ERC: a theory of equity, reciprocity, and competition. Am. Econ. Rev. 90, 166–193. Burton-Chellew, M.N., El Mouden, C., West, S.A., 2016. Conditional cooperation and confusion in public-goods experiments. Proc. Natl. Acad. Sci. 113, 1291–1296. Burton-Chellew, M.N., El Mouden, C., West, S.A., 2016. Conditional cooperation and confusion in public-goods experiments. Proc. Natl. Acad. Sci. 113, 1291–1296. Camerer, C.F., Dreber, A., Forsell, E., Ho, T.-H., Huber, J., Johannesson, M., Kirchler, M., Almenberg, J., Altmejd, A., Chan, T., Heikensten, E., Holzmeister, F., Imai, T., Isaksson, S., Nave, G., Pfeiffer, T., Razen, M., Wu, H., 2016. Evaluating replicability of laboratory experiments in economics. Science 351, 1433–1436. Camerer, C.F., Dreber, A., Johannesson, M., 2019. Replication and other practices for improving scientific quality in experimental economics. In: Schram, A., Ule, A. (Eds.), Handbook of Research Methods and Applications in Experimental Economics. Edward Elgar Publishing, Cheltenham, pp. 83–102. C l A W Ni l U H S E Ø T dd B T J R 2013 Gi d k i di E L 118 280 283 Camerer, C.F., Dreber, A., Forsell, E., Ho, T.-H., Huber, J., Johannesson, M., Kirchler, M., Almenberg, J., Altmejd, A., Chan, T., Heikensten, E., Holzmeister, F., Imai, T., Isaksson, S., Nave, G., Pfeiffer, T., Razen, M., Wu, H., 2016. Evaluating replicability of laboratory experiments in economics. Science 351, 1433–1436. Camerer, C.F., Dreber, A., Johannesson, M., 2019. Replication and other practices for improving scientific quality in experimental economics. In: Schram, A., Ule, A. (Eds.), Handbook of Research Methods and Applications in Experimental Economics. Edward Elgar Publishing, Cheltenham, pp. 83–102. Cappelen A W Nielsen U H Sørensen E Ø Tungodden B Tyran J R 2013 Give and take in dictator games Econ Lett 118 280 283 g p y y p Camerer, C.F., Dreber, A., Johannesson, M., 2019. Replication and other practices for improving scientific quality in experimental economics. In: Schram, A., Ule, A. (Eds.), Handbook of Research Methods and Applications in Experimental Economics. Games and Economic Behavior 135 (2022) 338–355 Edward Elgar Publishing, Cheltenham, pp. 83–102. Cappelen A W Nielsen U H Sørensen E Ø Tungodden B Tyran J R 2013 Give and take in dictator games Econ Lett 118 280 283 Cappelen, A.W., Nielsen, U.H., Sørensen, E. Ø, Tungodden, B., Tyran, J.-R., 2013. Give and take in dictator games. Econ. Let Cartwright, E., 2016. A comment on framing effects in linear public good games. J. Econ. Sci. Assoc. 2, 73–84. C T N Pl C R 2014 Mi i d f i i h ll h i f l d Cason, T.N., Plott, C.R., 2014. Misconceptions and game form recognition: challenges to theories of revealed preferenc 1235–1270. harness, G., Rabin, M., 2002. Understanding social preferences with simple tests. Q. J. Econ. 117, 817–869. Charness, G., Rabin, M., 2002. Understanding social preferences with simple tests. Q. J. Econ. 117, 817–869. Chaudhuri A 2011 Sustaining cooperation in laboratory public goods experiments: a selective survey of the l haudhuri, A., 2011. Sustaining cooperation in laboratory public goods experiments: a selective survey of the literature. Exp. R S dl T 1996 Th Th f E li i P bli G d d Cl b G d C b id U i i P C b id Cornes, R., Sandler, T., 1996. The Theory of Externalities, Public Goods and Club Goods. Cambridge University Press, Camb Cox, C.A., 2015. Decomposing the effects of negative framing in linear public goods games. Econ. Lett. 126, 63–65. Cornes, R., Sandler, T., 1996. The Theory of Externalities, Public Goods and Club Goods. Cambridge University Press, Cambridge. Cornes, R., Sandler, T., 1996. The Theory of Externalities, Public Goods and Club Goods. Cambridge University Press, Cambridge. Cox C A 2015 Decomposing the effects of negative framing in linear public goods games Econ Lett 126 63–65 Cox, C.A., Stoddard, B., 2015. Framing and feedback in social dilemmas with partners and strangers. Games 6, 394–412. C J C F i d D Gj d S 2007 A bl d l f i i d f i G E B h 59 17 45 , . ., , ., . g p g . , . Cox, J.C., Friedman, D., Gjerstad, S., 2007. A tractable model of reciprocity and fairness. Games Econ. Behav. 59, 17–45. , , , , g p g , Cox, J.C., Friedman, D., Gjerstad, S., 2007. A tractable model of reciprocity and fairness. Games Econ. Behav. 59, 17–45. References Bartling, B., Engl, F., Weber, R.A., 2015. Game form misconceptions are not necessary for a willingness-to-pay vs. willi Assoc. 1, 72–85. Game form misconceptions are not necessary for a willingness-to-pay vs. willingness-to-accept gap. J. Econ. Sci. Bartling, B., Fehr, E., Özdemir, Y., 2021. Does market interaction erode moral value Battigalli, P., Dufwenberg, M., 2007. Guilt in games. Am. Econ. Rev. 97, 170–176. 25 Alternatively, when it is not possible to measure misperceptions directly (e.g., in representative surveys), econometric techniques such as those proposed by Goldin and Reck (2020) can be applied to correct for potential measurement error ex post. 353 orenok, O., Millner, E.L., Razzolini, L., 2014. Taking, giving, and impure altruism in dictator games. Exp. Econ. 17, 488–500. oszegi, B., Rabin, M., 2008. Choices, situations, and happiness. J. Public Econ. 92, 1821–1832. d d bli d f i l h h l ( d ) h db k f g pp J Ledyard, J.O., 1995. Public goods: a survey of experimental research. In: Roth, A.E., Kagel, J.H. (Eds.), The Handbook of Experimental Economics. Princeton University Press, Princeton, pp. 111–181. O., Millner, E.L., Razzolini, L., 2014. Taking, giving, and impure altruism in dictator games. Exp. Econ. 17, 488–500. B., Rabin, M., 2008. Choices, situations, and happiness. J. Public Econ. 92, 1821–1832. Games and Economic Behavior 135 (2022) 338–355 Testing ‘conditional cooperation’ in a field experiment. Am. Econ. Rev. 94, 1717–1722. Fujimoto, H., Park, E.-S., 2010. Framing effects and gender differences in voluntary public goods provision experiments. J. Socio-Econ. 39, 455–457. Fujimoto, H., Park, E. S., 2010. Framing effects and gender differences in voluntary public goods provision experiments. J. Gächter, S., 2007. Conditional cooperation: behavioral regularities from the lab and the field and their policy implication j , , , , g g y p g p p J , Gächter, S., 2007. Conditional cooperation: behavioral regularities from the lab and the field and their policy implications. In: Frey, B.S., Stutzer, A. (Eds.), Psychology and Economics: A Promising New Cross-Disciplinary Field (CESifo Seminar Series). The MIT Press, Cambridge, pp. 19–50. Gächter S Herrmann B 2009 Reciprocity culture and human cooperation: previous insights and a new cross cultural experiment Philos Trans R Soc p g p y p y ( ) Psychology and Economics: A Promising New Cross-Disciplinary Field (CESifo Seminar Series). The MIT Press, Cambridge, pp. 19–50. Gächter, S., Herrmann, B., 2009. Reciprocity, culture, and human cooperation: previous insights and a new cross-cultural experiment. Philos. Trans. - R. Soc., Biol. Sci. 364, 791–806. Psychology and Economics: A Promising New Cross-Disciplinary Field (CESifo Seminar Series). The MIT Press, Cambridge, pp. 19–50. Gächter, S., Herrmann, B., 2009. Reciprocity, culture, and human cooperation: previous insights and a new cross-cultural experiment. Philos. Trans. - R. Soc., Gächter, S., Kölle, F., Quercia, S., 2017. Reciprocity and the tragedies of maintaining and providing the commons. Nat. Hum. Behav. 1, 650–656. Goldin, J., Reck, D., 2020. Revealed-preference analysis with framing effects. J. Polit. Econ. 128, 2759–2795. er, B., 2015. Subject pool recruitment procedures: organizing experiments with ORSEE. J. Econ. Sci. Assoc. 1, 114–125. n, G., 1968. The tragedy of the commons. Science 162, 1243–1248. Horton, J.J., Rand, D.G., Zeckhauser, R.J., 2011. The online laboratory: conducting experiments in a real labor market. Exp. Econ. 14, 399–425. Houser, D., Kurzban, R., 2002. Revisiting kindness and confusion in public goods experiments. Am. Econ. Rev. 92, 1062–1069. Horton, J.J., Rand, D.G., Zeckhauser, R.J., 2011. The online laboratory: conducting experiments in a real labor market. Exp. Econ. 14, 399 425. Houser, D., Kurzban, R., 2002. Revisiting kindness and confusion in public goods experiments. Am. Econ. Rev. 92, 1062–1069. Games and Economic Behavior 135 (2022) 338–355 Cambridge University Press O t E 2006 Th l dd d f l b t i t f th t d f i tit ti d l J Ostrom, E., 1990. Governing the Commons. The Evolution of Institutions for Collective Action. Cambridge University Press, Cambridge. Ostrom, E., 1990. Governing the Commons. The Evolution of Institutions for Collective Action. Cambridge University Press, Cambridge. Ostrom, E., 1990. Governing the Commons. The Evolution of Institutions for Collective Action. Cambridge University Press, Cambridge. Ostrom, E., 1990. Governing the Commons. The Evolution of Institutions for Collective Action. Cambridge University Press, Cambridge. Ostrom, E., 2006. The value-added of laboratory experiments for the study of institutions and common-pool resources. J. Econ. Behav. Organ. 61, 149–163. Park, E.-S., 2000. Warm-glow versus cold-prickle: a further experimental study of framing effects on free-riding. J. Econ. Behav. Organ. 43, 405–421. Plott, C.R., Zeiler, K., 2005. The willingness to pay-willingness to accept gap, the “endowment effect”, subject misconceptions, and experimental procedures for eliciting valuations. Am. Econ. Rev. 95, 530–545. Ostrom, E., 2006. The value-added of laboratory experiments for the study of institutions and common-pool resources. J. Econ. Behav. Organ. 61, 149–163. Park, E.-S., 2000. Warm-glow versus cold-prickle: a further experimental study of framing effects on free-riding. J. Econ. Behav. Organ. 43, 405–421. Plott, C.R., Zeiler, K., 2005. The willingness to pay-willingness to accept gap, the “endowment effect”, subject misconceptions, and experimental procedures for eliciting valuations. Am. Econ. Rev. 95, 530–545. y p y p J Park, E.-S., 2000. Warm-glow versus cold-prickle: a further experimental study of framing effects on free-riding. J. Econ. B Park, E.-S., 2000. Warm-glow versus cold-prickle: a further experimental study of framing e Park, E. S., 2000. Warm glow versus cold prickle: a further experimental study of framing effects on free riding. J. Econ. Behav. Organ. 43, 405 421. Plott, C.R., Zeiler, K., 2005. The willingness to pay-willingness to accept gap, the “endowment effect”, subject misconceptions, and experimental procedures for eliciting valuations. Am. Econ. Rev. 95, 530–545. Plott, C.R., Zeiler, K., 2005. The willingness to pay-willingness to accept gap, the “endowmen for eliciting valuations. Am. Econ. Rev. 95, 530–545. Poppe, M., 2005. The specificity of social dilemma situations. J. Econ. Psychol. 26, 431–441. Poppe, M., 2005. The specificity of social dilemma situations. J. Econ. Psychol. 26, 431–441. b f h d Rabin, M., 1993. Incorporating fairness into game-theory and economics. Am. Econ. Rev. 83, 1281–1302. Games and Economic Behavior 135 (2022) 338–355 , , p g g y , Ramalingam, A., Morales, A.J., Walker, J.M., 2019. Peer punishment of acts of omission versus acts of commission in give and take social dilemmas. J. Econ. Behav. Organ. 164, 133–147. , , p g g y , Ramalingam, A., Morales, A.J., Walker, J.M., 2019. Peer punishment of acts of omission versus acts of commission in give and take social dilemmas. J. Econ. Behav. Organ. 164, 133–147. Ramalingam, A., Morales, A.J., Walker, J.M., 2019. Peer punishment of acts of omission versus acts of commission in give Behav. Organ. 164, 133–147. Rand, D.G., Nowak, M.A., 2013. Human cooperation. Trends Cogn. Sci. 17, 413–425. R i D E l S K f ld M 2010 C di i l i d l Rand, D.G., Nowak, M.A., 2013. Human cooperation. Trends Cogn. Sci. 17, 413 425. Rustagi, D., Engel, S., Kosfeld, M., 2010. Conditional cooperation and costly monitoring explain success in forest commons management. Science 330, 961–965. , , , , p g , Rustagi, D., Engel, S., Kosfeld, M., 2010. Conditional cooperation and costly monitoring explain success in forest commons management. Science 330, 961–965. ell, J., Son, Y., 1997. Comparing public goods and common pool resources: three experiments. Soc. Psychol. Q. 60, 118–137. elten, R., 1967. Die Strategiemethode zur Erforschung des eingeschränkt rationalen Verhaltens im Rahmen eines Oligopolexp Selten, R., 1967. Die Strategiemethode zur Erforschung des eingeschränkt rationalen Verhaltens im Rahmen eines Oligopolexperimentes. In: Sauermann, H. (Ed.), Beiträge zur Experimentellen Wirtschaftsforschung. J.C.B. Mohr (Paul Siebeck), Tübingen, pp. 136–168. S b E Y i L 2021 T i h b h i i i l A E R 111 687 719 Selten, R., 1967. Die Strategiemethode zur Erforschung des eingeschränkt rationalen Verhaltens im Rahmen eines Oligopolexperimentes. In: Sauermann, H. (Ed.), Beiträge zur Experimentellen Wirtschaftsforschung. J.C.B. Mohr (Paul Siebeck), Tübingen, pp. 136–168. , ., . g g g g p p . : , . (Ed.), Beiträge zur Experimentellen Wirtschaftsforschung. J.C.B. Mohr (Paul Siebeck), Tübingen, pp. 136–168. g g g g p p (Ed.), Beiträge zur Experimentellen Wirtschaftsforschung. J.C.B. Mohr (Paul Siebeck), Tübingen, pp. 136–168. nowberg, E., Yariv, L., 2021. Testing the waters: behavior across participant pools. Am. Econ. Rev. 111, 687–719. Sonnemans, J., Schram, A., Offerman, T., 1998. Public good provision and public bad prevention: the effect of framing. J. Econ. Behav. Organ. 34, 143–161. Spranca, M., Minsk, E., Baron, J., 1991. olk, S., Thöni, C., Ruigrok, W., 2012. Temporal stability and psychological foundations of cooperation preferences. J. Econ. Beh Wilson, B.J., 2012. Contra private fairness. Am. J. Econ. Sociol. 71, 407–435. Games and Economic Behavior 135 (2022) 338–355 l O G h S l A S C 2021 C li d i i l i lfl i d i lfih i i i d k i l Gächter, S., Maule, A.J., Starmer, C., 2021. Contextualised strong reciprocity explains selfless cooperation despite selfish intui stics. Sci. Rep. 11, 13868. Iturbe-Ormaetxe, I., Ponti, G., Tomás, J., Ubeda, L., 2011. Framing effects in public goods: Prospect Theory and experimental evidence. Games Econ. Behav. 72, 439–447. Khadjavi, M., Lange, A., 2015. Doing good or doing harm: experimental evidence on giving and taking in public good games. Exp. Econ. 18, 432–441. Kocher, M.G., Cherry, T., Kroll, S., Netzer, R.J., Sutter, M., 2008. Conditional cooperation on three continents. Econ. Lett. 101, 175–178. Ledyard, J.O., 1995. Public goods: a survey of experimental research. In: Roth, A.E., Kagel, J.H. (Eds.), The Handbook of Experimental Economics. Princeton University Press, Princeton, pp. 111–181. University Press, Princeton, pp. 111–181. Levin, S.A., 2014. Public goods in relation to competition, cooperation, and spite. Proc. Natl. Acad. Sci. 111, 10838–10845. Levine, D.K., 1998. Modeling altruism and spitefulness in experiments. Rev. Econ. Dyn. 1, 593–622. List, J.A., 2007. On the interpretation of giving in dictator games. J. Polit. Econ. 115, 482–493. 354 Games and Economic Behavior 135 (2022) 338–355 S. Gächter, F. Kölle and S. Quercia MacKay, D.J.C., Cramton, P., Ockenfels, A., Stoft, S., 2015. Price carbon — I will if you will. Nature 526, 315–316. d f ll d k d h ff MacKay, D.J.C., Cramton, P., Ockenfels, A., Stoft, S., 2015. Price carbon — I will if you will. Nature 526, 315–316. Maniadis, Z., Tufano, F., List, J.A., 2014. One swallow doesn’t make a summer: new evidence on anchoring effects. Maniadis, Z., Tufano, F., List, J.A., 2014. One swallow doesn’t make a summer: new evidence on anchoring effects. Am. Econ. Rev. 104, 277–290. Messer, K.D., Zarghamee, H., Kaiser, H.M., Schulze, W.D., 2007. New hope for the voluntary contributions mechanism: the effects of context. J. Public Econ. 91, 1783–1799. J g Messer, K.D., Zarghamee, H., Kaiser, H.M., Schulze, W.D., 2007. New hope for the voluntary contributions mechanism: the effects of context. J. Public Econ. 91, 1783–1799. Miettinen, T., Kosfeld, M., Fehr, E., Weibull, J., 2020. Revealed preferences in a sequential prisoners’ dilemma: a horse-ra Econ. Behav. Organ. 173, 1–25. Ostrom, E., 1990. Governing the Commons. The Evolution of Institutions for Collective Action. Games and Economic Behavior 135 (2022) 338–355 Omission and commission in judgment and choice. J. Exp. Soc. Psychol. 27, 76–105. Sonnemans, J., Schram, A., Offerman, T., 1998. Public good provision and public bad prevention: the effect of framing. J. Econ. Behav. Organ. 34, 143–161. Spranca, M., Minsk, E., Baron, J., 1991. Omission and commission in judgment and choice. J. Exp. Soc. Psychol. 27, 76–105. p J j g J p Thöni, C., Volk, S., 2018. Conditional cooperation: review and refinement. Econ. Lett. 171, 37–40. Thöni, C., Volk, S., 2018. Conditional cooperation: review and refinement. Econ. Lett. 171, 37–40. van Dijk, E., Wilke, H., 1997. Is it mine or is it ours? Framing property rights and decision making in social dilemmas. Organ. Behav. Hum. Decis. Process. 71, 195–209. van Dijk, E., Wilke, H., 1997. Is it mine or is it ours? Framing property rights and decision making in social dilemmas. Organ. Behav. Hum. Decis. Process. 71, 195–209. Volk, S., Thöni, C., Ruigrok, W., 2012. Temporal stability and psychological foundations of cooperation preferences. J. Econ. Behav. Organ. 81, 664–676. Wilson, B.J., 2012. Contra private fairness. Am. J. Econ. Sociol. 71, 407–435. Volk, S., Thöni, C., Ruigrok, W., 2012. Temporal stability and psychological foundations of cooperation preferences. J. Econ. Behav. Organ. 81, 664–676. Wilson, B.J., 2012. Contra private fairness. Am. J. Econ. Sociol. 71, 407–435. 355
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Targeting a therapeutic LIF transgene to muscle via the immune system ameliorates muscular dystrophy
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ARTICLE 1 Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095-1606, USA. 2 Molecular, Cellular & Integrative Physiology Program, University of California, Los Angeles, CA 90095-1606, USA. 3 Department of Neurology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095, USA. 4 Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095, USA. 5These authors contributed equally: Steven S. Welc, Ivan Flores. Correspondence and requests for materials should be addressed to J.G.T. (email: jtidball@physci.ucla.edu) Targeting a therapeutic LIF transgene to muscle via the immune system ameliorates muscular dystrophy Coinciding with the unpredictable ebb and flow of pathology in muscular dys- trophy, inflammatory cells invade in numbers that coincide with the magnitude of muscle pathology. Although the immune cell infiltrate in dystrophin-deficient muscle is complex7–12, macro- phages comprise the vast majority and they can reach con- centrations that exceed 107 cells per pound of muscle at the peak of mdx pathology7. They are also rich sources of regulatory molecules that can amplify muscle damage but also promote muscle repair and regeneration in muscular dystrophy7,13,14. Thus, the introduction of therapeutic transgenes that are expressed at elevated levels in activated macrophages or other immune cells could provide a strategy for intrinsically-regulated targeting of therapeutic molecules specifically to dystrophic muscles at the time of active pathology and at levels that were commensurate with the extent of pathology. We assessed effects of the transgene on mdx pathology over the course of the disease, sampling at the acute onset of pathology (1- month-old), the period of successful regeneration (3-months- old), and the late, progressive stage of pathology (12-months-old) in TA muscles. Diaphragm muscles show a progressive pathology following disease onset. The CD11b/LIF transgene reduced numbers of macrophages expressing the pan-macrophage marker F4/80 at the stages of pathology characterized by extensive, muscle inflammation (1-month-old in TA; 12-months-old in diaphragm) (Fig. 2e–g). The transgene also reduced numbers of CD163+ macrophages at the acute onset of pathology in both TA and diaphragm (Fig. 2h–j) but did not affect numbers of CD68+ macrophages in either muscle at any stage of the disease that we tested (Supplementary Fig. 2). In this investigation, we test whether transplantation of bone marrow cells (BMCs) into which we have introduced a leukemia inhibitory factor (LIF) transgene controlled by the human CD11b promoter reduces the pathology of mdx dystrophy. Although mdx pathology is less severe than DMD pathology, they share the pathological features of muscle inflammation and progressive fibrosis that persist over the entire lifespan and impair muscle function, reduce health and increase mortality. The CD11b pro- moter was chosen to drive the therapeutic transgene because CD11b is expressed at low or undetectable levels in myeloid precursors, but at increasingly elevated levels during myeloid cell differentiation and activation15–17. LIF was selected as a ther- apeutic molecule to test this system because it is expressed by macrophages and can influence muscle growth, fibrosis, and inflammation during disease or following injury18–21. Targeting a therapeutic LIF transgene to muscle via the immune system ameliorates muscular dystrophy Per- haps more valuable, the findings indicate that inflammatory cells can be exploited as natural vectors to deliver therapeutic trans- genes for the treatment of chronic diseases in which there is a significant inflammatory component. marrow-derived macrophages isolated bone marrow mononucl genic mice had a ~2.8-fold high wild-type (WT). After 9 days of fold higher in transgenic BMDM transgene expression increased w activation as monocytes differen Upon becoming fully-differentiat transgene had an autocrine eff increasing expression of Cd68 by arginase-1 (Arg1) by 47% and 42% present at high levels in macrop inflammatory phenotype (M1-bi present in macrophages that are reparative phenotype (M2-biased CD11b/LIF transgene reduces m fibrosis. We assayed whether th transgene affected mdx patholo muscle inflammation and fibr expression of Lif in the tibialis muscles of transgenic mice (CD1 observed that cells in inflammat mice showed higher levels of L mice (Fig. 2b–d). However, sera f elevation in LIF protein assayed b 19.25 ± 1.85 and LIF/mdx 26.19 ± P = 0.25; two-tailed t-test). We ences in the concentrations of cy influencing the pathology of mus 4, and IL-10) in the serum of tra transgenic mice (Supplementary We assessed effects of the trans course of the disease, sampling at month-old), the period of succ old), and the late, progressive stag in TA muscles. Diaphragm musc following disease onset. The numbers of macrophages express F4/80 at the stages of patholo muscle inflammation (1-month diaphragm) (Fig. 2e–g). The tran CD163+ macrophages at the acu and diaphragm (Fig. 2h–j) but di macrophages in either muscle at tested (Supplementary Fig. 2). We tested whether the CD11b accumulation in mdx muscles, w reduction in numbers or activit promote fibrosis of dystrophic diaphragm showed significant red acute onset of pathology, and the collagen type 1 accumulation in months-old (Fig. 2k–m). The CD accumulation of collagen type 1 reduced accumulation of collagen late stages of pathology and redu marrow-derived macrophages (BMDMs) (Fig. 1a). Freshly- isolated bone marrow mononuclear cells (BMMCs) from trans- genic mice had a ~2.8-fold higher Lif expression compared to wild-type (WT). After 9 days of culture, Lif expression was ~10- fold higher in transgenic BMDMs than WT (Fig. 1b). Thus, LIF transgene expression increased with increased CD11b promoter activation as monocytes differentiate into mature macrophages. Targeting a therapeutic LIF transgene to muscle via the immune system ameliorates muscular dystrophy Our find- ings show that this intervention significantly modifies intramus- cular macrophage phenotype and reduces inflammation and fibrosis of dystrophic muscle, thereby reducing pathology. Per- haps more valuable, the findings indicate that inflammatory cells can be exploited as natural vectors to deliver therapeutic trans- genes for the treatment of chronic diseases in which there is a significant inflammatory component. pp y g We tested whether the CD11b/LIF transgene reduced collagen accumulation in mdx muscles, which would be consistent with a reduction in numbers or activity of CD163 macrophages that promote fibrosis of dystrophic muscle23. Both the TA and diaphragm showed significant reductions in collagen type 1 at the acute onset of pathology, and the transgene completely abrogated collagen type 1 accumulation in the TA muscle, at least until 12- months-old (Fig. 2k–m). The CD11b/LIF transgene also reduced accumulation of collagen type 1 in diaphragms (Fig. 2n–p) and reduced accumulation of collagen types 3 and 5 in diaphragms at late stages of pathology and reduced collagen type 5 in 3-month- old TA muscles (Supplementary Fig. 3). pp y g Because the CD11b/LIF transgene prevented collagen type 1 accumulation in TA muscles and collagen type 1 is primarily responsible for increased muscle stiffness caused by fibrosis, we assayed for changes in the passive mechanical properties of TA muscles in CD11b/LIF transgenic mdx mice. We subjected TA muscles to cyclic, dynamic loading using 20% strains at a 0.6/s strain rate, which is within the physiological range. Lissajous Targeting a therapeutic LIF transgene to muscle via the immune system ameliorates muscular dystrophy Upon becoming fully-differentiated macrophages, the CD11b/LIF transgene had an autocrine effect on macrophage phenotype, increasing expression of Cd68 by ~31% and reducing Cd163 and arginase-1 (Arg1) by 47% and 42%, respectively (Fig. 1c). CD68 is present at high levels in macrophages that are biased to a pro- inflammatory phenotype (M1-biased). Arginase and CD163 are present in macrophages that are biased toward a pro-fibrotic and reparative phenotype (M2-biased)22. O ver recent years, investigators have identified numerous, potentially-therapeutic molecules for the treatment of Duchenne muscular dystrophy (DMD), a lethal and incurable muscle-wasting disease. For example, systemic delivery of therapeutic agents that can inhibit fibrosis (e.g., block TGFβ function1–3), inhibit muscle wasting (e.g., myostatin blocking molecules4), and increase numbers of muscle stem cells called satellite cells (e.g., Klotho5) all reduce pathology in the mdx mouse model of DMD. However, systemic delivery of any of these molecules presents risks of unintended off-target effects which provide an obstacle to their clinical application for the treatment of DMD. In addition, the occurrence of muscle pathology is not synchronized in DMD patients. The unpredictable timing and severity of disease vary between muscles in a single individual at any given time, and also vary between locations in a single muscle6. Even if a therapeutic agent were specifically targeted to dystrophic muscle, achieving delivery only when pathology is active presents an additional challenge. CD11b/LIF transgene reduces mdx muscle inflammation and fibrosis. We assayed whether the expression of the CD11b/LIF transgene affected mdx pathology, focusing on influences on muscle inflammation and fibrosis. We confirmed elevated expression of Lif in the tibialis anterior (TA) and diaphragm muscles of transgenic mice (CD11b/LIF mdx mice) (Fig. 2a) and observed that cells in inflammatory lesions in CD11b/LIF mdx mice showed higher levels of LIF protein than non-transgenic mice (Fig. 2b–d). However, sera from transgenic mice showed no elevation in LIF protein assayed by ELISA (mean ± sem: WT/mdx 19.25 ± 1.85 and LIF/mdx 26.19 ± 4.86 pg/ml , n = 3 per data set, P = 0.25; two-tailed t-test). We also found no significant differ- ences in the concentrations of cytokines previously implicated in influencing the pathology of muscular dystrophy (IFNγ, TNF, IL- 4, and IL-10) in the serum of transgenic mice, compared to non- transgenic mice (Supplementary Fig. 1). Nature has provided a naturally-occurring system for targeted delivery of potentially-therapeutic molecules to dystrophic muscle at stages of the disease when pathology is active. NATURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038/s41467-019-10614-1 | www.nature.com/naturecommunications Targeting a therapeutic LIF transgene to muscle via the immune system ameliorates muscular dystrophy Steven S. Welc 1,5, Ivan Flores2,5, Michelle Wehling-Henricks1, Julian Ramos1, Ying Wang2, Carmen Bertoni3 & James G. Tidball 1,2,4 Steven S. Welc 1,5, Ivan Flores2,5, Michelle Wehling-Henricks1, Julian Ramos1, Ying Wang2, Carmen Bertoni3 & James G. Tidball 1,2,4 Many potentially therapeutic molecules have been identified for treating Duchenne muscular dystrophy. However, targeting those molecules only to sites of active pathology is an obstacle to their clinical use. Because dystrophic muscles become extensively inflamed, we tested whether expressing a therapeutic transgene in leukocyte progenitors that invade muscle would provide selective, timely delivery to diseased muscle. We designed a transgene in which leukemia inhibitory factor (LIF) is under control of a leukocyte-specific promoter and transplanted transgenic cells into dystrophic mice. Transplantation diminishes pathology, reduces Th2 cytokines in muscle and biases macrophages away from a CD163+/CD206+ phenotype that promotes fibrosis. Transgenic cells also abrogate TGFβ signaling, reduce fibro/adipogenic progenitor cells and reduce fibrogenesis of muscle cells. These findings indicate that leukocytes expressing a LIF transgene reduce fibrosis by suppressing type 2 immunity and highlight a novel application by which immune cells can be genetically modified as potential therapeutics to treat muscle disease. 1 Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095-1606, USA. 2 Molecular, Cellular & Integrative Physiology Program, University of California, Los Angeles, CA 90095-1606, USA. 3 Department of Neurology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095, USA. 4 Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095, USA. 5These authors contributed equally: Steven S. Welc, Ivan Flores. Correspondence and requests for materials should be addressed to J.G.T. (email: jtidball@physci.ucla.edu) 1 NATURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038/s41467-019-10614-1 | www.nature.com/naturecommunications TURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038 ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 O ver recent years, investigators have identified numerous, potentially-therapeutic molecules for the treatment of Duchenne muscular dystrophy (DMD), a lethal and incurable muscle-wasting disease. For example, systemic delivery of therapeutic agents that can inhibit fibrosis (e.g., block TGFβ function1–3), inhibit muscle wasting (e.g., myostatin blocking molecules4), and increase numbers of muscle stem cells called satellite cells (e.g., Klotho5) all reduce pathology in the mdx mouse model of DMD. However, systemic delivery of any of these molecules presents risks of unintended off-target effects which provide an obstacle to their clinical application for the treatment of DMD. Targeting a therapeutic LIF transgene to muscle via the immune system ameliorates muscular dystrophy In addition, the occurrence of muscle pathology is not synchronized in DMD patients. The unpredictable timing and severity of disease vary between muscles in a single individual at any given time, and also vary between locations in a single muscle6. Even if a therapeutic agent were specifically targeted to dystrophic muscle, achieving delivery only when pathology is active presents an additional challenge. Nature has provided a naturally-occurring system for targeted delivery of potentially-therapeutic molecules to dystrophic muscle at stages of the disease when pathology is active. Coinciding with the unpredictable ebb and flow of pathology in muscular dys- trophy, inflammatory cells invade in numbers that coincide with the magnitude of muscle pathology. Although the immune cell infiltrate in dystrophin-deficient muscle is complex7–12, macro- phages comprise the vast majority and they can reach con- centrations that exceed 107 cells per pound of muscle at the peak of mdx pathology7. They are also rich sources of regulatory molecules that can amplify muscle damage but also promote muscle repair and regeneration in muscular dystrophy7,13,14. Thus, the introduction of therapeutic transgenes that are expressed at elevated levels in activated macrophages or other immune cells could provide a strategy for intrinsically-regulated targeting of therapeutic molecules specifically to dystrophic muscles at the time of active pathology and at levels that were commensurate with the extent of pathology. In this investigation, we test whether transplantation of bone marrow cells (BMCs) into which we have introduced a leukemia inhibitory factor (LIF) transgene controlled by the human CD11b promoter reduces the pathology of mdx dystrophy. Although mdx pathology is less severe than DMD pathology, they share the pathological features of muscle inflammation and progressive fibrosis that persist over the entire lifespan and impair muscle function, reduce health and increase mortality. The CD11b pro- moter was chosen to drive the therapeutic transgene because CD11b is expressed at low or undetectable levels in myeloid precursors, but at increasingly elevated levels during myeloid cell differentiation and activation15–17. LIF was selected as a ther- apeutic molecule to test this system because it is expressed by macrophages and can influence muscle growth, fibrosis, and inflammation during disease or following injury18–21. Our find- ings show that this intervention significantly modifies intramus- cular macrophage phenotype and reduces inflammation and fibrosis of dystrophic muscle, thereby reducing pathology. NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 Significant findings were verified with biological replicates of experiments from independent donors. * Indicates significantly different from WT BMDMs at P < 0.05. P-values based on two-tailed t-test. F-test Cd206 (P = 0.0258) and Il10 (P = 0.0311). Source data are provided as a Source Data file Cs into macrophages increases CD11b/LIF transgene expression, causing suppression of M2-biased macrophage ma ences in the level of Cd11b expression in C57BL6 BMCs stimulated with MCSF and differentiated to macrophages for 3 macrophages increases CD11b/LIF transgene expression, causing suppression of M2-biased macrophage markers. the proportions of dMHC+ fibers in 3-months-old and 12- months-old diaphragms were increased by the transgene (Sup- plementary Fig. 4C). Collectively, these observations indicate that the CD11b/LIF transgene does not impair muscle growth or regeneration, despite the reduction of CD163+ cells. figures obtained by measuring force–strain relationships showed that muscle stiffness (indicated by the slope of the tangent to the loading phase of each cycle) was significantly less in CD11b/LIF transgenic mdx mice (Fig. 2q, r). In addition, the transgenic mdx muscles showed less energy dissipation during each cycle of loading (proportional to the area inside each hysteresis loop during a cycle of loading/unloading) (Fig. 2q, s), indicating higher mechanical efficiency in the CD11b/LIF transgenic muscles. Transplanted CD11b/LIF cells reduce inflammation. Our ana- lyses of CD11b/LIF transgenic mdx mice showed that the trans- gene reduces muscle inflammation and fibrosis, thereby validating the transgene as a therapeutic molecule for muscular dystrophy. However, our primary goal in the investigation was to determine whether transplanted bone marrow derived cells (BMDCs) could serve as vehicles to deliver therapeutic molecules to dystrophic muscle through a clinically-relevant approach; in particular, we questioned whether transplantation of genetically- modified BMCs into dystrophic animals provides a strategy for targeted delivery of therapeutic cargo to diseased muscle. We assayed treatment effects in 6-months-old mdx mice at 4 months post-bone marrow transplantation (BMT) for scientific and technical reasons. First, we anticipated that a likely, beneficial outcome of leukocyte delivery of a LIF transgene to muscle would be reductions in fibrosis. Our previous work5 showed that 6- months-old mdx muscles show significantly elevated CD11b/LIF transgene does not impair muscle growth. Although previous investigations showed that M2-biased mac- rophages promote muscle fibrosis, they also promote regeneration23,24. NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 Source data are provided as a Source Data file 4 20 15 10 5 0 BMMCs BMDMs WT CD11b/ LIF WT CD11b/ LIF 3 2 1 Relative expression Relative expression 0 3 days 5 days 7 days 9 days CD11b # LIF a b 4 20 15 10 5 0 2.0 2.5 1.5 1.0 0.5 0.0 M1 M2 Th1 Th2 n.d. BMMCs BMDMs WT WT BMDMs CD11b/LIF BMDMs CD11b/ LIF WT CD11b/ LIF 3 2 1 Relative expression Relative expression Relative expression 0 3 days CD68 iNOS CD163 CD206 ARG1 ARG2 TNF IFNγ IL-1β TGFβ1 SOCS3 IL-6 IL-12 IL-4 IL-10 5 days 7 days 9 days CD11b # LIF a b c b 2.0 2.5 1.5 1.0 0.5 0.0 M1 M2 Th1 Th2 n.d. WT BMDMs CD11b/LIF BMDMs Relative expression CD68 iNOS CD163 CD206 ARG1 ARG2 TNF IFNγ IL-1β TGFβ1 SOCS3 IL-6 IL-12 IL-4 IL-10 c Th2 M1 Fig. 1 Differentiation of BMCs into macrophages increases CD11b/LIF transgene expression, causing suppression of M2-biased macrophage markers. a QPCR data showing differences in the level of Cd11b expression in C57BL6 BMCs stimulated with MCSF and differentiated to macrophages for 3–9 days. Values are normalized to 3-day cultures, n = 4 for each data set; * indicates significantly different from 3-day data set and # indicates significantly different from 5- and 7-day data sets at P < 0.05. P-values based on ANOVA with Tukey’s multiple comparison test. For all histograms in the figure, the bars indicate mean ± sem. b QPCR data showing increased Lif expression in freshly-isolated BMMCs and BMDMs cultured for 9 days from CD11b/LIF transgenic mice compared to transgene negative littermate controls (WT). Data are presented as mean ± sem. BMCs were isolated from three independent donors, n = 3 per data set. * Indicates significantly different from WT at P < 0.05. P-values based on two-tailed t-test. F-test BMDMs day 9 (P = 0.0038). c QPCR analysis shows that CD11b/LIF BMDMs have increased the expression of Cd68 and reduced the expression of Cd163 and Arg1. Data are presented as mean ± sem, n = 5 for each data set, n = 4 for WT BMDMs Inos, and CD11b/LIF BMDMs Arg1 data sets (P < 0.05). n.d. indicates that no expression was detected. Data presented for BMDMs (b, c) were isolated from a single donor animal of each genotype and cultured as n = 5 technical replicates. NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 4 20 15 10 5 0 2.0 2.5 1.5 1.0 0.5 0.0 M1 M2 Th1 Th2 n.d. BMMCs BMDMs WT WT BMDMs CD11b/LIF BMDMs CD11b/ LIF WT CD11b/ LIF 3 2 1 Relative expression Relative expression Relative expression 0 3 days CD68 iNOS CD163 CD206 ARG1 ARG2 TNF IFNγ IL-1β TGFβ1 SOCS3 IL-6 IL-12 IL-4 IL-10 5 days 7 days 9 days CD11b # LIF a b c Fig. 1 Differentiation of BMCs into macrophages increases CD11b/LIF transgene expression, causing suppression of M2-biased macrophage markers. a QPCR data showing differences in the level of Cd11b expression in C57BL6 BMCs stimulated with MCSF and differentiated to macrophages for 3–9 days. Values are normalized to 3-day cultures, n = 4 for each data set; * indicates significantly different from 3-day data set and # indicates significantly different from 5- and 7-day data sets at P < 0.05. P-values based on ANOVA with Tukey’s multiple comparison test. For all histograms in the figure, the bars indicate mean ± sem. b QPCR data showing increased Lif expression in freshly-isolated BMMCs and BMDMs cultured for 9 days from CD11b/LIF transgenic mice compared to transgene negative littermate controls (WT). Data are presented as mean ± sem. BMCs were isolated from three independent donors, n = 3 per data set. * Indicates significantly different from WT at P < 0.05. P-values based on two-tailed t-test. F-test BMDMs day 9 (P = 0.0038). c QPCR analysis shows that CD11b/LIF BMDMs have increased the expression of Cd68 and reduced the expression of Cd163 and Arg1. Data are presented as mean ± sem, n = 5 for each data set, n = 4 for WT BMDMs Inos, and CD11b/LIF BMDMs Arg1 data sets (P < 0.05). n.d. indicates that no expression was detected. Data presented for BMDMs (b, c) were isolated from a single donor animal of each genotype and cultured as n = 5 technical replicates. Significant findings were verified with biological replicates of experiments from independent donors. * Indicates significantly different from WT BMDMs at P < 0.05. P-values based on two-tailed t-test. F-test Cd206 (P = 0.0258) and Il10 (P = 0.0311). Results A CD11b regulated LIF transgene suppresses M2-biased mar- kers. We generated mice with a LIF transgene under control of the CD11b promoter (CD11b/LIF transgenic mice). Quantitative PCR (QPCR) analysis of Cd11b mRNA levels confirmed that Cd11b expression increased as BMCs differentiate into bone 2 ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 We tested this possibility by assaying for effects of the transgene on TA muscle fiber cross-sectional area as an index of regeneration and found no difference in TA fiber size between transgenic and non-transgenic mdx mice at any age sampled (Supplementary Fig. 4A). We also assayed for the pro- portion of muscle fibers that expressed developmental myosin heavy chain (dMHC), which is upregulated in regenerating fibers. We observed a higher proportion of dMHC+ fibers in TAs of CD11b/LIF transgenic mdx mice at 3-months-old and a trend for more dMHC+ fibers at 1-month and 12-months-old, compared to non-transgenic mdx mice (Supplementary Fig. 4B). Similarly, TURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038/s41467-019-10614-1 | www.nature.com/naturecommunications 3 ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 umulation of type I and type III collagen. We also showed that -months-old, mdx limb muscles contain elevated numbers of biased macrophages that contribute to muscle fibrosis5. The nical rationale for sampling at 6 months is that engraftment l d ll k i d li i i showed that high levels of engraftment could be achieved 4 months post-BMT. NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 At the time of tissue collection from transplant recipie circulating leukocytes were 86.6% donor-derived (sem = 1 25) QPCR f l h d h CD11b/LIF i i 3 2 1 0 TA Diaphragm 1 month 3 months 12 months 1 month 3 months 12 months 1 month 3 months 12 months 1 month 3 months 12 months 1 month 3 months 12 months 1 month 3 months 12 months WT/mdx LIF/mdx LIF LIF Relative expression 60 40 20 0 30,000 20,000 10,000 0 0 2000 4000 6000 8000 MFI (arbitrary units) F4/80+ cells/mm3 CD163+ cells/mm3 0 2000 4000 6000 8000 CD163+ cells/mm3 25 50 40 30 20 10 0 600 25,000 20,000 15,000 10,000 5000 0 500 Energy dissipation Collagen 1: diaphragm # # #φ #φ #φ # # # # # # # # # # # #φ Collagen 1: TA CD163+ cells: diaphragm CD163+ cells: TA F4/80+ cells: TA F4/80+ cells: diaphragm Stiffness 400 300 200 100 0 20 15 10 5 0 Collagen 1 (% section area) Collagen 1 (% section area) Work-loop area Stiffness (mN) 30,000 20,000 10,000 0 F4/80+ cells/mm3 1 2 3 4 5 4000 3000 2000 1000 0 0 Strain (%) Force (mN) 15 5 10 20 a b c d e f g h i j k l m n o p q r s RTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-106 LIF 60 40 20 0 MFI (arbitrary units) d MFI (arbitrary units) d 3 2 1 0 TA Diaphragm WT/mdx LIF/mdx LIF Relative expression a d c a b c 1 month 3 months 12 months 30,000 20,000 10,000 0 F4/80+ cells/mm3 #φ # F4/80+ cells: TA f 1 month 3 months 12 months # # # # F4/80+ cells: diaphragm 30,000 20,000 10,000 0 F4/80+ cells/mm3 g 3 f f e g month months months 1 month 3 months 12 months 0 2000 4000 6000 8000 CD163+ cells/mm3 # # # # CD163+ cells: TA i 3 j 1 month 3 months 12 months 0 2000 4000 6000 8000 CD163+ cells/mm3 # # CD163+ cells: diaphragm j i h i CD163+ cells/mm3 1 month 3 months 12 months 25 #φ Collagen 1: TA 20 15 10 5 0 Collagen 1 (% section area) m k m l l 1 month 3 months 12 months 50 40 30 20 10 0 Collagen 1: diaphragm # # #φ #φ Collagen 1 (% section area) p n o p o 1 2 3 4 5 4000 3000 2000 1000 0 0 Strain (%) Force (mN) 15 5 10 20 q q 25,000 20,000 15,000 10,000 5000 0 Stiffness Stiffness (mN) r month months months 600 500 Energy dissipation 400 300 200 100 0 Work-loop area s Strain (%) accumulation of type I and type III collagen. NATURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038/s41467-019-10614-1 | www.nature.com/naturecommunications ARTICLE Additionally, the transgene affected the expression of Th2 cytokines associated with M2-biased macro- phage activation, IL-4 (Il4) and IL-10 (Il10), which were reduced by ~79% and ~84%, respectively (Fig. 3a). Reduced cytokine expression was accompanied by a ~2.8-fold increase in the expression of suppressor of cytokine signaling 3 (Socs3) in CD11b/LIF BMT recipients (Fig. 3a). Socs3 expression is activated by LIF25 and its elevation in muscles of CD11b/LIF BMT recipients verifies an increase in LIF signaling in muscle. that expressed detectible CCR2 but found that the proportion of CD68+ or CD206+ macrophages that expressed CCR2 was not influenced by the transgene (Fig. 4c, d). This indicates that reductions in macrophage-derived CCR2 in muscles reflect reductions in macrophage numbers, rather than ablating the expression of CCR2 in macrophages in CD11b/LIF BMT recipients. However, stimulation of BMDMs with LIF reduced Ccl2 expression and CCL2 protein secretion (Fig. 4e, f), indicating that LIF acts directly on macrophages to negatively regulate Ccl2. In addition, F4/80+ macrophages were prominent sources of CCL2 in mdx muscle (Fig. 4g), and transplantation of CD11b/LIF BMCs reduced the proportion of F4/80+ macrophages that expressed detectible CCL2 by 15% (Fig. 4h). p g g We tested the effect of CD11b/LIF BMT on macrophage numbers and phenotype because changes in macrophages have profound effects on dystrophic muscle pathology7,13,14,26. We performed immunohistochemistry using anti-F4/80, to identify total macrophage populations, or anti-CD68 (M1-biased macro- phages), anti-CD163 (M2-biased), or anti-CD206 (M2-biased). Mdx mice that received CD11b/LIF BMCs had 37% fewer F4/80+ cells compared to mice receiving WT BMCs (Fig. 3b). Quantita- tion of CD68+, CD163+ and CD206+ macrophages showed no difference in CD68+ cells (mean ± sem: WT BMT/mdx 17,525 ± 1502 and LIF BMT/mdx 16,377 ± 1440 cells/mm3, n = 5 per data set, P = 0.60; two-tailed t-test), a 32% reduction of CD163+ cells (Fig. 3e) and 46% fewer CD206+ cells (Fig. 3h) in the dystrophic muscle. However, numbers of CD4+ T-cells and neutrophils in mdx muscles were unaffected by transplantation of CD11b/LIF BMCs (Fig. 3k, l), indicating a selective reduction of M2-biased macrophages caused by transgenic BMDCs. Transplanted CD11b/LIF cells reduce muscle fibrosis. Fibrosis of dystrophin-deficient muscle is largely driven by arginine metabolism by arginase expressed by M2-biased macrophages23. Arginine hydrolysis by arginase produces metabolites that are utilized to generate substrate molecules necessary for connective tissue production28. ARTICLE Fig. 2 CD11b/LIF transgene expression modulates inflammation and reduces fibrosis. a QPCR data showing Lif expression in muscles of CD11b/LIF transgenic mdx mice (LIF/mdx) and non-transgenic littermates (WT/mdx), normalized to WT/mdx. TA muscles: n = 10. Diaphragm muscles: n = 8 or 7 for WT/mdx and LIF/mdx data sets, respectively. * Indicates significant difference versus WT/mdx (P < 0.05). For all histograms, bars indicate mean ± sem. b, c Cross-sections of WT/mdx (b) and LIF/mdx (c) TA muscles labeled with anti-LIF. Bars = 50 μm. d Mean fluorescence intensity (MFI) of inflammatory lesions in sections immunolabeled for LIF. * Indicates significant difference from WT/mdx (n = 4; P < 0.05). e–j Cross-sections of muscles from WT/mdx and LIF/mdx mice were immunolabeled with antibodies to F4/80 (e) and CD163 (h). Numbers of F4/80+ (f, g) and CD163+ (i, j) cells were normalized to muscle volume. Labeling of F4/80+ (e) and CD163+ (h) cells in TA muscle from 1-month-old WT/mdx muscle. Bars = 100 μm. N = 5 for each group, except n = 4 for F4/80 WT/mdx 1- and 12-month TA, LIF/mdx 12-month TA, WT/mdx 1- and 3-month diaphragm, and CD163 WT/mdx 12-month TA data sets. k–p Cross-sections of TA (k, i) and diaphragm (n, o) muscles from 12-month-old WT/mdx (k, n) and LIF/mdx (l, o) mice were immunolabeled with anti-collagen type 1. Bars = 50 μm. The volume fraction of muscle occupied by collagen type 1 (m, p). N = 5 for each group, except n = 4 for 3-month TA. * Indicates significant difference versus age-matched WT/mdx mice (P < 0.05). # and Φ indicate significant difference versus 1- and 3-months-old, genotype-matched mice, respectively (P < 0.05). P-values based on two-tailed t-test. q–s The passive mechanical properties of TA muscles of WT/mdx (curves 1 and 2) and LIF/mdx (curves 3–5) mice were measured in-situ. Lissajous curves (q) show passive stiffness (r) and energy dissipation (s) of TAs. N = 2 and 3 for WT/mdx and LIF/mdx groups, respectively. * Indicates significant difference versus WT/mdx mice. P-values based on two-tailed t-test. Source data are provided as a Source Data file (LIF BMT/mdx mice) had reduced expression of the M2-biased markers Cd163, CD206 (Mrc1), and arginase-2 (Arg2) expression by 51%, 49%, and 43%, respectively (Fig. 3a). This effect resembles the autocrine effect of CD11b/LIF on macrophages in vitro (Fig. 1c). NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 We also showed that at 6-months-old, mdx limb muscles contain elevated numbers of M2-biased macrophages that contribute to muscle fibrosis5. The technical rationale for sampling at 6 months is that engraftment of transplanted cells takes time and our preliminary experiments showed that high levels of engraftment could be achieved by 4 months post-BMT. showed that high levels of engraftment could be achieved by 4 months post-BMT. At the time of tissue collection from transplant recipients, circulating leukocytes were 86.6% donor-derived (sem = 1.14; n = 25). QPCR of muscles showed that CD11b/LIF recipients NATURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038/s41467-019-10614-1 | www.nature.com/naturecommunicatio 4 NATURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038/s41467-019-10614-1 | www.nature.com/naturecommunications ARTICLE Because we observed reductions in M2- biased macrophages in muscles of mdx mice that were recipients of CD11b/LIF BMT and lower levels of expression of Arg2, we assayed whether fibrosis was affected. Transplantation of CD11b/ LIF BMCs reduced collagen types 1, 3, and 5 in mdx muscle by ~41%, 22%, and 25%, respectively, compared to WT BMT reci- pients (Fig. 5a–i). However, the anti-fibrotic effect of CD11b/LIF BMT cannot be solely attributed to reductions of arginine metabolism by M2-biased macrophages. QPCR data showed that mRNA levels of collagen types 1 alpha 1 (Col1a1), 3 alpha 1 (Col3a1), and 5 alpha 3 (Col5a3) were reduced by ~57%, 51%, and 30%, respectively, in CD11b/LIF BMC recipients (Fig. 5j), indicating treatment effects on fibrogenic cells, in addition to effects on macrophages that provide substrate for fibrogenesis. LIF reduces Ccl2 expression in muscle and macrophages. The large reductions of M2-biased macrophages in dystrophic muscle of mice transplanted with CD11b/LIF BMCs (Fig. 3) suggest that LIF inhibits their recruitment. Because abrogation of CCR2 signaling reduces macrophage accumulation in dystrophic muscle27, we tested whether CCR2 signaling was affected by LIF. QPCR assays showed reduced expression of Ccr2 and its ligands Ccl2, Ccl8 and Ccl12 in muscles of CD11b/LIF BMT recipients, and a strong trend for lower levels of Ccl7 expression (P = 0.06) (Fig. 4a). M2-biased macrophages can act directly on fibrogenic cells through TGFβ which activates fibro/adipogenic progenitor cells (FAPs) into fibroblasts and stimulates fibroblasts to produce collagen29–32. TGFβ can also activate Wnt-signaling, which increases myogenic-to-fibrogenic conversion of muscle stem cells, further contributing to dystrophic muscle fibrosis33. We tested whether the CD11b/LIF BMT affected key transcripts of the Wnt and TGFβ pro-fibrotic pathways. Although there was no effect on the expression of Tgfb1 or Axin2, a Wnt-target gene (Fig. 5k), the expression of downstream TGFβ target genes connective tissue growth factor (Ctgf), fibronectin (Fn1), and snail family zinc finger 1 (Snai1)34–37 were reduced by ~33%, 43%, and 33%, respectively (Fig. 5k). We next tested the possibility that LIF acts directly on macrophages to inhibit CCR2 signaling in vitro. Unexpectedly, brief periods of macrophage stimulation with LIF had no effect on Ccr2 expression and extended periods significantly increased Ccr2 expression (Fig. 4b). We assayed whether the CD11b/LIF transgene affected the numbers of intramuscular macrophages 5 5 TURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038/s41467-019-10614-1 | www.nature.com/naturecommunications ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 6 WT BMT/mdx LIF BMT/mdx WT BMT/mdx LIF BMT/mdx 5 4 3 2.0 1.5 1.0 0.5 0.0 20,000 F4/80+ 15,000 10,000 5000 0 6000 5000 4000 3000 2000 1000 30,000 20,000 10,000 CD206+ CD4+ CD163+ 0 0 10 20 30 40 150 100 50 0 Neutrophils 0 M1 M2 Th1 Th2 CD68 iNOS CD163 CD206 ARG1 ARG2 TNF IFNγ IL-1β IL-6 IL-12 IL-4 IL-10 SOCS3 Relative expression F4/80+ cells/mm3 CD163+ cells/mm3 CD206+ cells/mm3 CD4+ cells/mm3 Ly6B.2+ cells/mm3 a b c d e f g h i j k l splantation of CD11b/LIF transgenic BMCs into mdx mice reduces inflammation in dystrophic muscle. a QPCR analysis s ion of CD11b/LIF transgenic BMCs into mdx recipients (LIF BMT/mdx) reduced expression of transcripts associated wit 6 WT BMT/mdx LIF BMT/mdx 5 4 3 2.0 1.5 1.0 0.5 0.0 M1 M2 Th1 Th2 CD68 iNOS CD163 CD206 ARG1 ARG2 TNF IFNγ IL-1β IL-6 IL-12 IL-4 IL-10 SOCS3 Relative expression a a Th2 20,000 F4/80+ 15,000 10,000 5000 0 F4/80+ cells/mm3 b b d c d 6000 5000 4000 3000 2000 1000 CD163+ 0 CD163+ cells/mm3 e e g f g 30,000 20,000 10,000 CD206+ 0 CD206+ cells/mm3 h h j i j i WT BMT/mdx LIF BMT/mdx 150 100 50 0 Neutrophils Ly6B.2+ cells/mm3 l CD4+ 0 10 20 30 40 CD4+ cells/mm3 k l 3 l k Fig. 3 Transplantation of CD11b/LIF transgenic BMCs into mdx mice reduces inflammation in dystrophic muscle. a QPCR analysis shows that the transplantation of CD11b/LIF transgenic BMCs into mdx recipients (LIF BMT/mdx) reduced expression of transcripts associated with M2-biased macrophages (Cd163, Cd206, and Arg2), Th2 cytokines (Il4 and Il10), and increased expression of the negative regulator of cytokine signaling (Socs3) compared to WT BMT mdx recipients (WT BMT/mdx) 4 months post-transplantation. N = 7 or 8 for WT BMT/mdx and LIF BMT/mdx data sets, respectively, except n = 7 for LIF BMT/mdx Arg1 data set. * Indicates significantly different from WT BMT/mdx recipients at P < 0.05. F-test Ifng (P = 0.0145), Il6 (P < 0.0001), Il4 (P = 0.0015), Il10 (P < 0.0001), and Socs3 (P = 0.0061). For all histograms in the figure, the bars indicate mean ± sem. b–j Cross-sections of TA muscles from WT BMT/mdx (c, f, i) or LIF BMT/mdx (d, g, j) mice were immunolabeled with antibodies to F4/80 (c, d), CD163 (f, g), and CD206 (i, j). NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 3 WT BMT/mdx CCR2 Vehicle LIF Vehicle LIF LIF BMT/mdx WT BMT/mdx LIF BMT/mdx WT BMT/mdx LIF BMT/mdx WT BMT/mdx LIF BMT/mdx 2 Relative expression Relative expression Relative expression 1 0 100 50 2.0 1.5 1.0 0.5 0.0 40 30 20 10 0 (CCR2+/CD68+) × 100 (CCR2+/CD206+) × 100 80 60 40 20 250 60 (CCL2+/F4/80+) × 100 50 40 30 20 10 0 200 150 CCL2 (pg/ml) 100 50 0 0 3 2 1 0 3 h 24 h 3 h 24 h 6 h 24 h CCR2 CCL2 CCL7 CCL8 CCL12 CCL2 Vehicle LIF CCL2 a b c d e f g h Fig. 4 Transplantation of CD11b/LIF transgenic BMCs disrupts Ccl2 expression in dystrophic muscles by inhibiting macrophage expression of CCL2. a QPCR analysis shows that TA muscles from LIF BMT/mdx recipients have reduced expression of Ccr2 and its ligands Ccl2, Ccl7 (P = 0.06), Ccl8, and Ccl12. N = 7 or 8 for WT BMT/mdx and LIF BMT/mdx data sets, respectively, except n = 7 for LIF BMT/mdx Ccl8 data set. * Indicates significantly different from WT BMT/mdx recipients at P < 0.05. F-test Ccr2 (P = 0.0087), Ccl2 (P < 0.0001), Ccl7 (P = 0.0001), Ccl8 (P = 0.001), and Ccl12 (P = 0.001). For all histograms in the figure, the bars indicate mean ± sem. b QPCR analysis for Ccr2 gene expression of BMDMs treated with recombinant LIF (10 ng/ml) for 3- and 24-h. c, d Muscle sections co-labeled with antibodies to CD68 (c) or CD206 (d) and CCR2 show no change in the proportions of cells co-expressing CCR2 between transplant recipient groups. N = 5 for each data set. e QPCR analysis shows reduced Ccl2 gene expression in BMDMs stimulated with LIF as described in (b). f ELISA of conditioned media showed less CCL2 secreted into the media of BMDMs stimulated with LIF for 6- and 24-h compared to control cultures. For cell culture experiments, N = 5 technical replicates for each data set, cells for each time point were isolated from independent donors. Significant findings were verified with biological replicates of experiments from independent donors. P-values based on two-tailed t-test. F-test CCL2 protein 24 h (P = 0.0337). g, h Cross-sections of TA muscles from WT BMT/mdx or LIF BMT/mdx mice were immunolabeled with antibodies to F4/80 (green) and CCL2 (red) show that F4/80+ cells express CCL2 (g). NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 f ELISA of conditioned media showed less CCL2 secreted into the media of BMDMs stimulated with LIF for 6- and 24-h compared to control cultures. For cell culture experiments, N = 5 technical replicates for each data set, cells for each time point were isolated from independent donors. Significant findings were verified with biological replicates of experiments from independent donors. P-values based on two-tailed t-test. F-test CCL2 protein 24 h (P = 0.0337). g, h Cross-sections of TA muscles from WT BMT/mdx or LIF BMT/mdx mice were immunolabeled with antibodies to F4/80 (green) and CCL2 (red) show that F4/80+ cells express CCL2 (g). Nuclei are stained blue with DAPI. Bar = 10 μm. h The proportion of F4/80+ cells co- expressing CCL2 was reduced in LIF BMT/mdx recipients. N = 5 for each data set, * indicates significantly different from WT BMT/mdx recipients at P < 0.05. P-values based on two-tailed t-test. Source data are provided as a Source Data file a negative regulator of TGFβ1 expression in macrophages. However, Tgfb1 gene expression was not reduced after 3 h of LIF stimulation, suggesting that LIF-mediated inhibition of Tgfb1 could be a secondary effect. LIF reduces macrophage TGFβ1 expression. Although we observed no effect of CD11b/LIF BMT on Tgfb1 mRNA in whole muscle homogenates, we assayed more specifically for effects on TGFβ expression in intramuscular macrophages by assaying the proportion of macrophages that expressed TGFβ. We found that there were 17.7% fewer intramuscular macrophages that expres- sed detectible TGFβ in CD11b/LIF recipients, compared to WT recipients (Fig. 6a). Interestingly, the greatest reduction of TGFβ expressing macrophages was seen in inflammatory lesions of CD11b/LIF recipients (Fig. 6c) compared to WT recipients (Fig. 6b). LIF reduces fibrogenesis and Ctgf mRNA in muscle cells. TGFβ signaling promotes the fibrogenic conversion of myogenic cells in dystrophic muscle, thereby contributing to fibrosis33. Because transplantation of CD11b/LIF BMCs into mdx mice reduces fibrosis, we tested whether LIF reduces the proportion of myo- genic cells acquiring a fibrogenic phenotype. Muscle sections that were double-labeled with anti-Pax7, a marker of satellite cells, and anti-HSP47, a collagen-specific molecular chaperone38,39 showed that the proportion of Pax7+ cells that expressed HSP47 was reduced by 27.8% in CD11b/LIF recipients (Fig. 7a–c); this We tested whether reduced TGFβ1 expression in CD11b/LIF BMT recipients reflected direct actions of LIF on macrophages to inhibit TGFβ1 expression. NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 Nuclei are stained blue with DAPI. Bar = 10 μm. h The proportion of F4/80+ cells co- expressing CCL2 was reduced in LIF BMT/mdx recipients. N = 5 for each data set, * indicates significantly different from WT BMT/mdx recipients at P < 0.05. P-values based on two-tailed t-test. Source data are provided as a Source Data file 3 WT BMT/mdx CCR2 Vehicle LIF LIF BMT/mdx 2 Relative expression Relative expression 1 0 3 2 1 0 3 h 24 h CCR2 CCL2 CCL7 CCL8 CCL12 a b CCR2 Vehicle LIF Relative expression 3 2 1 0 3 h 24 h b 3 WT BMT/mdx LIF BMT/mdx 2 Relative expression 1 0 CCR2 CCL2 CCL7 CCL8 CCL12 a b a WT BMT/mdx LIF BMT/mdx 50 40 30 20 10 0 (CCR2+/CD206+) × 100 d WT BMT/mdx LIF BMT/mdx 100 (CCR2+/CD68+) × 100 80 60 40 20 0 c d Vehicle LIF Relative expression 2.0 1.5 1.0 0.5 0.0 3 h 24 h CCL2 e WT BMT/mdx LIF BMT/mdx 60 (CCL2+/F4/80+) × 100 50 40 30 20 10 0 h 250 200 150 CCL2 (pg/ml) 100 50 0 6 h 24 h Vehicle LIF CCL2 f g g Fig. 4 Transplantation of CD11b/LIF transgenic BMCs disrupts Ccl2 expression in dystrophic muscles by inhibiting macrophage expression of CCL2. a QPCR analysis shows that TA muscles from LIF BMT/mdx recipients have reduced expression of Ccr2 and its ligands Ccl2, Ccl7 (P = 0.06), Ccl8, and Ccl12. N = 7 or 8 for WT BMT/mdx and LIF BMT/mdx data sets, respectively, except n = 7 for LIF BMT/mdx Ccl8 data set. * Indicates significantly different from WT BMT/mdx recipients at P < 0.05. F-test Ccr2 (P = 0.0087), Ccl2 (P < 0.0001), Ccl7 (P = 0.0001), Ccl8 (P = 0.001), and Ccl12 (P = 0.001). For all histograms in the figure, the bars indicate mean ± sem. b QPCR analysis for Ccr2 gene expression of BMDMs treated with recombinant LIF (10 ng/ml) for 3- and 24-h. c, d Muscle sections co-labeled with antibodies to CD68 (c) or CD206 (d) and CCR2 show no change in the proportions of cells co-expressing CCR2 between transplant recipient groups. N = 5 for each data set. e QPCR analysis shows reduced Ccl2 gene expression in BMDMs stimulated with LIF as described in (b). NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 Bars = 50 μm. The numbers of F4/80+ (b), CD163+ (e), and CD206+ (h) cells normalized to muscle volume were reduced in LIF BMT/ mdx recipients. Similarly, cross-sections were immunolabeled with antibodies to CD4 and Ly-6B.2 (neutrophils) to test for changes in the concentrations of other populations of immune cells. There was no change in the concentrations of CD4+ (k) and Ly-6B.2+ (l) cells. N = 5 for each data set, except n = 4 for CD206 LIF BMT/mdx data set. * Indicates significantly different from WT BMT/mdx recipients at P < 0.05. All P-values based on two-tailed t-test. Source data are provided as a Source Data file Fig. 3 Transplantation of CD11b/LIF transgenic BMCs into mdx mice reduces inflammation in dystrophic muscle. a QPCR analysis shows that the transplantation of CD11b/LIF transgenic BMCs into mdx recipients (LIF BMT/mdx) reduced expression of transcripts associated with M2-biased macrophages (Cd163, Cd206, and Arg2), Th2 cytokines (Il4 and Il10), and increased expression of the negative regulator of cytokine signaling (Socs3) compared to WT BMT mdx recipients (WT BMT/mdx) 4 months post-transplantation. N = 7 or 8 for WT BMT/mdx and LIF BMT/mdx data sets, respectively, except n = 7 for LIF BMT/mdx Arg1 data set. * Indicates significantly different from WT BMT/mdx recipients at P < 0.05. F-test Ifng (P = 0.0145), Il6 (P < 0.0001), Il4 (P = 0.0015), Il10 (P < 0.0001), and Socs3 (P = 0.0061). For all histograms in the figure, the bars indicate mean ± sem. b–j Cross-sections of TA muscles from WT BMT/mdx (c, f, i) or LIF BMT/mdx (d, g, j) mice were immunolabeled with antibodies to F4/80 (c, d), CD163 (f, g), and CD206 (i, j). Bars = 50 μm. The numbers of F4/80+ (b), CD163+ (e), and CD206+ (h) cells normalized to muscle volume were reduced in LIF BMT/ mdx recipients. Similarly, cross-sections were immunolabeled with antibodies to CD4 and Ly-6B.2 (neutrophils) to test for changes in the concentrations of other populations of immune cells. There was no change in the concentrations of CD4+ (k) and Ly-6B.2+ (l) cells. N = 5 for each data set, except n = 4 for CD206 LIF BMT/mdx data set. * Indicates significantly different from WT BMT/mdx recipients at P < 0.05. All P-values based on two-tailed t-test. Source data are provided as a Source Data file NATURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038/s41467-019-10614-1 | www.nature.com/naturecommunicatio 6 ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 Source data are provided as a Source Data file 50 40 30 20 2.0 Relative expression Relative expression 1.5 1.0 0.5 Col 1 Col 3 Col 5 0.0 2.0 WT BMT/mdx LIF BMT/mdx 1.5 1.0 0.5 0.0 n2 β1 GF FN AI1 10 0 Collagen 5 Collagen 5 (% section area) g h i j k i g h Relative expression 2.0 WT BMT/mdx LIF BMT/mdx 1.5 1.0 0.5 0.0 Axin2 TGFβ1 CTGF FN SNAI1 k 2.0 Relative expression 1.5 1.0 0.5 Col 1 Col 3 Col 5 0.0 j k Fig. 5 Transplantation of CD11b/LIF transgenic BMCs into mdx mice reduces muscle fibrosis. a–i TA muscles from WT BMT/mdx (b, e, h) and LIF BMT/ mdx transplant recipients (c, f, i) were immunolabeled for collagen types 1 (a–c), 3 (d–f), and 5 (g–i). Bars = 50 µm. The volume fraction of muscle occupied by collagen types 1 (a), 3 (d), and 5 (g) was reduced in LIF BMT/mdx recipients. N = 5 for WT BMT/mdx and LIF BMT/mdx data sets, except n = 4 WT BMT/mdx collagen type 3 and LIF BMT/mdx collagen type 1. * Indicates significantly different from WT BMT/mdx recipients at P < 0.05. F-test collagen type 3 (P = 0.0055) and type 5 (P = 0.0155). For all histograms in the figure, the bars indicate mean ± sem. j QPCR data presented as mean ± sem shows that LIF BMT/mdx recipients also had reduced expression of transcripts encoding Col1a1, Col3a1, and Col5a3. N = 7 or 8 for WT BMT/mdx and LIF BMT/mdx data sets, respectively, except n = 5 for Col5a3 data sets. k QPCR analysis of transcripts associated with the pro-fibrotic Wnt- (Axin2) and TGFβ1-signaling (Tgfb1, Ctgf, Fn1, and Snai1) pathways showed reduced expression of Ctgf, Fn1, and Snai1 in LIF BMT/mdx recipients. N = 7 or 8 for WT BMT/mdx and LIF BMT/mdx data sets, respectively, except n = 7 for LIF BMT/mdx Axin2 group. * Indicates significantly different from WT BMT/mdx recipients at P < 0.05. P-values based on two-tailed t-test. F-test Col1a1 (P = 0.0250). Source data are provided as a Source Data file shifted away from a myogenic phenotype, toward a fibrogenic phenotype40,41. Our data show that the transgene reduced the proportion of satellite cells that expressed ERTR7 in mdx muscle in vivo, similar to the reduction of satellite cells expressing HSP47 (Fig. 7c, d). NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 Source data are provided as a Source Data file 25 Collagen 1 20 Collagen 1 (% section area) 15 10 5 0 a b b c c 60 50 40 30 20 10 0 Collagen 3 Collagen 3 (% section area) d d f e f f e 50 40 30 20 2.0 Relative expression Relative expression 1.5 1.0 0.5 Col 1 Col 3 Col 5 0.0 2.0 WT BMT/mdx LIF BMT/mdx 1.5 1.0 0.5 0.0 Axin2 TGFβ1 CTGF FN SNAI1 10 0 Collagen 5 Collagen 5 (% section area) g h i j k Fig. 5 Transplantation of CD11b/LIF transgenic BMCs into mdx mice reduces muscle fibrosis. a–i TA muscles from WT BMT/mdx (b, e, h) and LIF BMT/ mdx transplant recipients (c, f, i) were immunolabeled for collagen types 1 (a–c), 3 (d–f), and 5 (g–i). Bars = 50 µm. The volume fraction of muscle occupied by collagen types 1 (a), 3 (d), and 5 (g) was reduced in LIF BMT/mdx recipients. N = 5 for WT BMT/mdx and LIF BMT/mdx data sets, except n = 4 WT BMT/mdx collagen type 3 and LIF BMT/mdx collagen type 1. * Indicates significantly different from WT BMT/mdx recipients at P < 0.05. F-test collagen type 3 (P = 0.0055) and type 5 (P = 0.0155). For all histograms in the figure, the bars indicate mean ± sem. j QPCR data presented as mean ± sem shows that LIF BMT/mdx recipients also had reduced expression of transcripts encoding Col1a1, Col3a1, and Col5a3. N = 7 or 8 for WT BMT/mdx and LIF BMT/mdx data sets, respectively, except n = 5 for Col5a3 data sets. k QPCR analysis of transcripts associated with the pro-fibrotic Wnt- (Axin2) and TGFβ1-signaling (Tgfb1, Ctgf, Fn1, and Snai1) pathways showed reduced expression of Ctgf, Fn1, and Snai1 in LIF BMT/mdx recipients. N = 7 or 8 for WT BMT/mdx and LIF BMT/mdx data sets, respectively, except n = 7 for LIF BMT/mdx Axin2 group. * Indicates significantly different from WT BMT/mdx recipients at P < 0.05. P-values based on two-tailed t-test. F-test Col1a1 (P = 0.0250). NATURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038/s41467-019-10614-1 | www.nature.com/naturecommunications NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 When we treated BMDMs with LIF for 24 h, Tgfb1 gene expression was reduced by 47% and secreted TGFβ protein expression by 29% (Fig. 6d, e), showing that LIF is 7 NATURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038/s41467-019-10614-1 | www.nature.com/naturecommunications ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 25 60 50 40 30 20 10 0 50 40 30 20 2.0 Relative expression Relative expression 1.5 1.0 0.5 Col 1 Col 3 Col 5 0.0 2.0 WT BMT/mdx LIF BMT/mdx 1.5 1.0 0.5 0.0 Axin2 TGFβ1 CTGF FN SNAI1 10 0 Collagen 1 Collagen 3 Collagen 5 20 Collagen 1 (% section area) Collagen 3 (% section area) Collagen 5 (% section area) 15 10 5 0 a b c d e f g h i j k 5 Transplantation of CD11b/LIF transgenic BMCs into mdx mice reduces muscle fibrosis. a–i TA muscles from WT BMT/mdx (b, e, h ransplant recipients (c, f, i) were immunolabeled for collagen types 1 (a–c), 3 (d–f), and 5 (g–i). Bars = 50 µm. The volume fractio pied by collagen types 1 (a), 3 (d), and 5 (g) was reduced in LIF BMT/mdx recipients. N = 5 for WT BMT/mdx and LIF BMT/mdx data s T BMT/mdx collagen type 3 and LIF BMT/mdx collagen type 1. * Indicates significantly different from WT BMT/mdx recipients at P gen type 3 (P = 0.0055) and type 5 (P = 0.0155). For all histograms in the figure, the bars indicate mean ± sem. j QPCR data presented s that LIF BMT/mdx recipients also had reduced expression of transcripts encoding Col1a1, Col3a1, and Col5a3. N = 7 or 8 for WT BM /mdx data sets, respectively, except n = 5 for Col5a3 data sets. k QPCR analysis of transcripts associated with the pro-fibrotic Wnt 1-signaling (Tgfb1, Ctgf, Fn1, and Snai1) pathways showed reduced expression of Ctgf, Fn1, and Snai1 in LIF BMT/mdx recipients. N = /mdx and LIF BMT/mdx data sets, respectively, except n = 7 for LIF BMT/mdx Axin2 group. * Indicates significantly different from W ents at P < 0.05. P-values based on two-tailed t-test. F-test Col1a1 (P = 0.0250). NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 d QPCR analysis of BMDMs treated with recombinant LIF (10 ng/ml) for 3- or 24-h shows that Tgfb1 expression is inhibited by LIF after 24 h of stimulation. e The concentration of secreted TGFβ was also reduced in BMDMs stimulated with LIF for 24 h, analyzed by ELISA. N = 5 technical replicates for each data set. Significant findings were verified with biological replicates of experiments from independent donors. * Indicates significantly different from control at P < 0.05. Source data are provided as a Source Data file PDGFRα+ cells that expressed HSP47 was unaffected by the transgene (Fig. 8d). The findings indicate that reductions in numbers of FAPs in the muscles of mdx mice receiving CD11b/ LIF BMT may contribute to reduced muscle fibrosis. integrin+ cells) from CD11b/LIF transgenic mdx mice showed lower expression levels of Fn1 and Col3a1 compared to non- transgenic mice (Supplementary Fig. 5). In addition, we observed strong trends for the reduction in expression of Serpinh1 (HSP47) and Col1a1 in freshly-isolated MPCs. y We then tested whether LIF influenced the fibrogenic activity of FAP-derived fibroblasts in vitro. We sorted FAPs (CD11b/31/ 45- PDGFRα+) from WT muscles (Fig. 8e) and subcultured them prior to stimulation with TGFβ1, LIF, or TGFβ1 + LIF41,42. We used fibroblasts derived from FAPs rather than freshly-isolated FAPs because fibroblasts differentiated from FAPs are the primary source of connective tissue proteins in muscle32. We tested if LIF affected Pdgfra expression in fibroblasts in vitro because enhanced PDGFRα signaling can cause pathological fibrosis43. However, LIF did not affect Pdgfra expression in fibroblasts (mean ± sem: control cells 1 ± 0.04 and LIF-treated cells 1.13 ± 0.23, n = 4 per data set, P = 0.61; two-tailed t-test). Treatments for 3 h with TGFβ1-induced Ctgf expression in fibroblasts, but LIF had no effect on basal or TGFβ1-induced Ctgf (Fig. 8f). The magnitude of TGFβ1-induced Ctgf expression in fibroblasts (1.9-fold) was less than in myoblasts (~11.6-fold) and myotubes (~7.1-fold) (Fig. 7e). TGFβ1, LIF or TGFβ1 + LIF had no effect on Fn1 or Col1a1 expression in fibroblasts (Fig. 8g, h). We then tested whether prolonged stimulation of fibroblasts with TGFβ1, LIF, or TGFβ1 + LIF affected Ctgf, Fn1, or Col1a1 expression. Similar to effects of brief stimulations, Ctgf expression was induced ~2.0-fold by TGFβ1 but the induction was not affected by LIF. NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 80 WT BMT/mdx LIF BMT/mdx 60 (TGFβ1+/F4/80+) × 100 40 20 1.5 150 100 50 0 TGFβ1 TGFβ1 Vehicle LIF TGFβ1 (pg/ml) 1.0 Relative expression 0.5 0.0 3 h 24 h 24 h 0 a b c d e Fig. 6 LIF inhibits macrophage TGFβ1 expression. a–c Muscle sections were co-labeled with antibodies to pro-fibrotic TGFβ (red) and the pan macrophage marker F4/80 (green) to test for changes in macrophage expression of TGFβ. Nuclei appear blue (DAPI). Bars = 25 μm. a The proportion of F4/80+ cells co-expressing TGFβ was reduced in LIF BMT/mdx recipients. The greatest reduction in the number of F4/80+ cells positive for TGFβ (orange) was in inflammatory lesions of LIF BMT/mdx (c) compared to WT BMT/mdx recipients (b). N = 5 for each data set, * indicates significantly different from WT BMT/mdx recipients at P < 0.05. For all histograms in the figure, the bars indicate mean ± sem. d QPCR analysis of BMDMs treated with recombinant LIF (10 ng/ml) for 3- or 24-h shows that Tgfb1 expression is inhibited by LIF after 24 h of stimulation. e The concentration of secreted TGFβ was also reduced in BMDMs stimulated with LIF for 24 h, analyzed by ELISA. N = 5 technical replicates for each data set. Significant findings were verified with biological replicates of experiments from independent donors. * Indicates significantly different from control at P < 0.05. Source data are provided as a Source Data file 80 WT BMT/mdx LIF BMT/mdx 60 (TGFβ1+/F4/80+) × 100 40 20 0 a b c b a c 1.5 TGFβ1 1.0 Relative expression 0.5 0.0 3 h 24 h d 150 100 50 0 TGFβ1 Vehicle LIF TGFβ1 (pg/ml) 24 h e e Fig. 6 LIF inhibits macrophage TGFβ1 expression. a–c Muscle sections were co-labeled with antibodies to pro-fibrotic TGFβ (red) and the pan macrophage marker F4/80 (green) to test for changes in macrophage expression of TGFβ. Nuclei appear blue (DAPI). Bars = 25 μm. a The proportion of F4/80+ cells co-expressing TGFβ was reduced in LIF BMT/mdx recipients. The greatest reduction in the number of F4/80+ cells positive for TGFβ (orange) was in inflammatory lesions of LIF BMT/mdx (c) compared to WT BMT/mdx recipients (b). N = 5 for each data set, * indicates significantly different from WT BMT/mdx recipients at P < 0.05. For all histograms in the figure, the bars indicate mean ± sem. NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 indicates that satellite cells had a less fibrogenic phenotype in CD11b/LIF recipients. Expression of Serpinh1, the gene that encodes HSP47, was also reduced 24% in the whole muscle lysate of CD11b/LIF recipients (mean ± sem: WT BMT/mdx 1 ± 0.08 and LIF BMT/mdx 0.76 ± 0.06, n = 7 and 8 per data set, respec- tively, P = 0.03; two-tailed t-test). We also assayed whether transplantation of CD11b/LIF BMCs affected the proportion of satellite cells that expressed ERTR7 in vivo. ERTR7 was chosen in addition to HSP47 because satellite cells in injured and aging muscle that display elevated levels of ERTR7 expression have g We also tested whether the CD11b/LIF transgene affected the phenotype of myogenic progenitor cells (MPCs) in later stages of mdx pathology by assaying for changes in the expression of fibrogenic genes in MPCs that were freshly-isolated from muscles of 14-months-old mice. MPCs (CD11b-CD31-CD45-Sca1-α7 TURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038/s41467-019-10614-1 | www.nature.com/naturecommunications 8 ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 There was also no effect of prolonged stimulation with TGFβ1 on the expression of Fn1 or Col1a1 (Fig. 8i–k). y We also examined the effects of LIF on TGFβ1-induced muscle cell fibrogenesis in vitro. We assayed myoblasts and myotubes treated with TGFβ1 and/or LIF for changes in expression of fibrogenic genes downregulated in CD11b/LIF BMT recipients (Ctgf, Fn1, and Col1a1; Fig. 5j, k). Co-stimulation with TGFβ1 and LIF inhibited Ctgf expression, compared to cells treated with TGFβ1 only (Fig. 7e, h). LIF also reduced basal Ctgf expression after 24 h of stimulation in myotubes. Fn1 expression was stable in myoblasts treated with TGFβ1, LIF, or TGFβ1 + LIF for 3 h (Fig. 7f). After 24 h, TGFβ1-induced Fn1 expression, but co- stimulation with LIF had no effect (Fig. 7i). TGFβ1 stimulation for 3 h induced the expression of Col1a1 in myotubes, and LIF attenuated TGFβ1-induced expression of Col1a1 in myotubes (Fig. 7g). LIF stimulation for 24 h reduced basal Col1a1 expression in myoblasts, but not TGFβ1-induced expression of Col1a1 (Fig. 7j). LIF reduces the prevalence of FAPs in dystrophic muscle. Because FAP-derived fibroblasts are important sources of con- nective tissue proteins, we assayed whether CD11b/LIF BMT affected FAP numbers in vivo or whether LIF affected the expression of fibrogenic proteins by FAP-derived fibroblasts in vitro. QPCR analysis showed that CD11b/LIF BMT recipients had a 47% reduction in Pdgfra expression (Fig. 8a) which could reflect fewer FAPs. Recipients of CD11b/LIF BMT had fewer cells that expressed PDGFRα and were double-negative for CD31 and CD45, which are FAPs42 (Fig. 8b, c), although the proportion of Transplanted CD11b/LIF cells do not affect muscle growth. NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 Because changes in macrophage phenotype and numbers influ- ence muscle regeneration and myogenesis14,44–47, we assayed TURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038/s41467-019-10614-1 | www.nature.com/naturecommunications 9 ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 40 40 60 80 100 15 CTGF FN COL1 CTGF FN COL1 #φ #φ #φ φ φ φ #φ # # # # # # # # 10 5 1.5 Relative expression Relative expression 1.0 0.5 0.0 Veh TGFβ1 LIF TGFβ1+ LIF Veh TGFβ1 LIF TGFβ1+ LIF Veh TGFβ1 LIF TGFβ1+ LIF 1.5 1.0 0.5 0.0 Relative expression 2.5 1.5 2.0 1.0 0.5 0.0 30 20 10 2.0 1.5 Relative expression Relative expression 1.0 0.5 0.0 Veh TGFβ1 LIF TGFβ1+ LIF Veh TGFβ1 LIF TGFβ1+ LIF Veh TGFβ1 LIF TGFβ1+ LIF 2 1 0 Relative expression 1.5 2.0 1.0 0.5 0.0 30 20 20 10 0 0 (HSP47+/Pax7+) × 100 (ERTR7+/Pax7+) × 100 WT BMT/mdx LIF BMT/mdx Myoblasts Myotubes a b c d e f g h j i Fig. 7 LIF inhibits fibrogenesis and TGFβ1-induced Ctgf expression in muscle cells. a TA muscle sections were co-labeled with antibodies to Pax7 (red) and HSP47 (green) in WT BMT/mdx (a) and LIF BMT/mdx (b) recipients. Nuclei appear blue (DAPI). Bars = 5 μm. c Fewer Pax7+ cells co-expressed HSP47 in LIF BMT/mdx recipients (green symbols) compared to WT BMT/mdx recipients (black symbols). d Muscle sections were also co-labeled with antibodies to Pax7 and fibrogenic marker Ertr7 to confirm that fewer Pax7+ cell acquired a fibrogenic phenotype in LIF BMT/mdx recipients. N = 5 for each data set, except n = 4 for WT BMT/mdx Pax7/HSP47 data set, * indicates significantly different from WT BMT/mdx at P < 0.05. P-values based on two-tailed t-test. For all histograms in the figure, the bars indicate mean ± sem. e–j Myoblasts (black symbols) and myotubes (green symbols) were stimulated with LIF (10 ng/ml) and TGFβ1 (10 ng/ml) for 3- (e–g) or 24-h (h–j). e, h LIF inhibited TGFβ1-induced Ctgf mRNA in myoblasts and myotubes after 3- and 24-h of stimulation. LIF inhibited basal Ctgf expression in myotubes at 24 h (h). f, i LIF did not affect Fn1 expression in myoblasts or myotubes after 3- or 24-h. Additionally, LIF attenuated TGFβ1-induced Col1a1 expression in myotubes, but not myoblasts after 3 h of stimulation (g). Myoblasts stimulated with LIF for 24 h had reduced Col1a1 expression (j). N = 4 technical replicates per group. NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 Additionally, LIF attenuated TGFβ1-induced Col1a1 expression in myotubes, but not myoblasts after 3 h of stimulation (g). Myoblasts stimulated with LIF for 24 h had reduced Col1a1 expression (j). N = 4 technical replicates per group. Significant findings were verified with biological replicates of experiments from independent cultures. * Indicates significantly different from control, # indicates significantly different from TGFβ1-stimulated, and Φ indicates significantly different from LIF-stimulated at P < 0.05. P-values based on ANOVA with Tukey’s multiple comparison test. Source data are provided as a Source Data file Fig. 7 LIF inhibits fibrogenesis and TGFβ1-induced Ctgf expression in muscle cells. a TA muscle sections were co-labeled with antibodies to Pax7 (red) and HSP47 (green) in WT BMT/mdx (a) and LIF BMT/mdx (b) recipients. Nuclei appear blue (DAPI). Bars = 5 μm. c Fewer Pax7+ cells co-expressed HSP47 in LIF BMT/mdx recipients (green symbols) compared to WT BMT/mdx recipients (black symbols). d Muscle sections were also co-labeled with antibodies to Pax7 and fibrogenic marker Ertr7 to confirm that fewer Pax7+ cell acquired a fibrogenic phenotype in LIF BMT/mdx recipients. N = 5 for each data set, except n = 4 for WT BMT/mdx Pax7/HSP47 data set, * indicates significantly different from WT BMT/mdx at P < 0.05. P-values based on two-tailed t-test. For all histograms in the figure, the bars indicate mean ± sem. e–j Myoblasts (black symbols) and myotubes (green symbols) were stimulated with LIF (10 ng/ml) and TGFβ1 (10 ng/ml) for 3- (e–g) or 24-h (h–j). e, h LIF inhibited TGFβ1-induced Ctgf mRNA in myoblasts and myotubes after 3- and 24-h of stimulation. LIF inhibited basal Ctgf expression in myotubes at 24 h (h). f, i LIF did not affect Fn1 expression in myoblasts or myotubes after 3- or 24-h. Additionally, LIF attenuated TGFβ1-induced Col1a1 expression in myotubes, but not myoblasts after 3 h of stimulation (g). Myoblasts stimulated with LIF for 24 h had reduced Col1a1 expression (j). N = 4 technical replicates per group. Significant findings were verified with biological replicates of experiments from independent cultures. * Indicates significantly different from control, # indicates significantly different from TGFβ1-stimulated, and Φ indicates significantly different from LIF-stimulated at P < 0.05. P-values based on ANOVA with Tukey’s multiple comparison test. Source data are provided as a Source Data file whether regeneration was affected in CD11b/LIF BMT recipients. NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 There were no significant differences in TA muscle weight, total muscle fiber number, proportions of regenerating fibers or muscle fiber size (Fig. 9a–d). No muscle fibers expressed dMHC in WT BMT/mdx or LIF BMT/mdx mice. Additionally, QPCR assays showed no effect of CD11b/LIF on expression of the myogenic transcription factors: Pax7, Myod1, Myog, or Mrf4 (Fig. 9e). These data indicate that the CD11b/LIF transgene did not influence processes through which immune cells modulate regeneration in mdx muscle. whether regeneration was affected in CD11b/LIF BMT recipients. There were no significant differences in TA muscle weight, total muscle fiber number, proportions of regenerating fibers or muscle fiber size (Fig. 9a–d). No muscle fibers expressed dMHC in WT BMT/mdx or LIF BMT/mdx mice. Additionally, QPCR assays showed no effect of CD11b/LIF on expression of the myogenic transcription factors: Pax7, Myod1, Myog, or Mrf4 (Fig. 9e). These data indicate that the CD11b/LIF transgene did not influence processes through which immune cells modulate regeneration in mdx muscle. recipients that is responsive to the magnitude and site of inflammation. This system also permits long-term delivery of therapeutic molecules following a single therapeutic intervention. Although tissues were analyzed 4 months following transplanta- tion in the present investigation, at that time circulating leukocyte populations were nearly 87% donor-derived. However, in humans experiencing BMT, stable mixed chimerism can persist for years in peripheral blood cell populations48,49, showing that long-term benefits to humans can result from a single transplantation. The potential therapeutic advantage of targeting therapeutic molecules to diseased tissue by using transgenes under control of the CD11b promoter is emphasized by comparing our findings with the outcomes of previous strategies to deliver LIF via hematopoietic cell transplantation. Transplantation of a hema- topoietic cell line in which the cells were multiply-transduced with a retroviral construct containing cDNA encoding LIF pro- duced high systemic levels of LIF and killed the recipient mice50,51. In those experiments the retrovirus-transplant reci- pients reached serum LIF concentrations at 1400 units/ml, although serum LIF was undetectable in mice transplanted with cells that did not contain the LIF expressing retrovirus50,51. This NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 Significant findings were verified with biological replicates of experiments from independent cultures. * Indicates significantly different from control, # indicates significantly different from TGFβ1-stimulated, and Φ indicates significantly different from LIF-stimulated at P < 0.05. P-values based on ANOVA with Tukey’s multiple comparison test. Source data are provided as a Source Data file a b c d FN Relative expression Veh TGFβ1 LIF TGFβ1+ LIF 1.5 1.0 0.5 0.0 f 15 CTGF #φ #φ # # 10 5 1.5 Relative expression 1.0 0.5 0.0 Veh TGFβ1 LIF TGFβ1+ LIF e COL1 # Veh TGFβ1 LIF TGFβ1+ LIF Relative expression 2.5 1.5 2.0 1.0 0.5 0.0 Myoblasts Myotubes g e g FN φ # Relative expression Veh TGFβ1 LIF TGFβ1+ LIF 2 1 0 i CTGF #φ #φ # # 30 20 10 2.0 1.5 Relative expression 1.0 0.5 0.0 Veh TGFβ1 LIF TGFβ1+ LIF h COL1 φ φ # # Veh TGFβ1 LIF TGFβ1+ LIF Relative expression 1.5 2.0 1.0 0.5 0.0 j Fig. 7 LIF inhibits fibrogenesis and TGFβ1-induced Ctgf expression in muscle cells. a TA muscle sections were co-labele Fig. 7 LIF inhibits fibrogenesis and TGFβ1-induced Ctgf expression in muscle cells. a TA muscle sections were co-labeled with antibodies to Pax7 (red) and HSP47 (green) in WT BMT/mdx (a) and LIF BMT/mdx (b) recipients. Nuclei appear blue (DAPI). Bars = 5 μm. c Fewer Pax7+ cells co-expressed HSP47 in LIF BMT/mdx recipients (green symbols) compared to WT BMT/mdx recipients (black symbols). d Muscle sections were also co-labeled with antibodies to Pax7 and fibrogenic marker Ertr7 to confirm that fewer Pax7+ cell acquired a fibrogenic phenotype in LIF BMT/mdx recipients. N = 5 for each data set, except n = 4 for WT BMT/mdx Pax7/HSP47 data set, * indicates significantly different from WT BMT/mdx at P < 0.05. P-values based on two-tailed t-test. For all histograms in the figure, the bars indicate mean ± sem. e–j Myoblasts (black symbols) and myotubes (green symbols) were stimulated with LIF (10 ng/ml) and TGFβ1 (10 ng/ml) for 3- (e–g) or 24-h (h–j). e, h LIF inhibited TGFβ1-induced Ctgf mRNA in myoblasts and myotubes after 3- and 24-h of stimulation. LIF inhibited basal Ctgf expression in myotubes at 24 h (h). f, i LIF did not affect Fn1 expression in myoblasts or myotubes after 3- or 24-h. Discussion h l a QPCR analysis shows that TA muscles from LIF BMT/mdx recipients have reduced Pdgfra gene expression. N = 7 or 8 for WT BMT/mdx and LIF BMT/mdx data sets, respectively, * indicates significantly different from WT BMT/mdx recipients at P < 0.05. P-values based on two-tailed t-test. For all histograms in the figure, the bars indicate mean ± sem. b To quantify the number of FAPs, muscle sections were co-labeled with antibodies to PDGFRα (red) and CD31, CD45 (green). Arrowheads indicate FAPs (CD31-CD45-PDGFRα+). Bar = 50 μm. c Fewer FAPs (CD31-CD45-PDGFRα+) in TA cross-sections of LIF BMT/mdx recipients compared to WT BMT/mdx recipients. N = 5 for each data set. d There was no detectible change in phenotype of PDGFRα+ cells assayed for co-expression of the fibrogenic marker HSP47. e FACS plots demonstrating strategy for sorting FAPs (Hoechst + CD11b-CD31-CD45-PDGFRα+). Fibroblasts derived from FAPs were stimulated with LIF (10 ng/ml) and/or TGFβ1 (10 ng/ml) for 3 h (f–h) or 3 days (i–k) and assayed by QPCR for Ctgf (f, i), Fn1 (g, j), and Col1a1 (h, k). N = 4 technical replicates for each data set. Significant findings were verified with biological replicates of cells sorted from independent donors. * Indicates significantly different from control cultures, # indicates significantly different from TGFβ1 treated cultures, and Φ indicates significantly different from LIF-treated cultures at P < 0.05. P-values based on ANOVA with Tukey’s multiple comparison test. Discussion h l Source data are provided as a Source Data file 40 20 0 (HSP47+/PDGFRα+) ×100 WT BMT/mdx LIF BMT/mdx d FAPs 5000 4000 3000 2000 1000 0 CD31–/CD45–/PDGFRα+ (cells/mm3) c b Relative expression 1.5 2.0 1.0 0.5 0.0 PDGFRα a d b c SSC-A 105 104 103 102 –102 –403 0 102 103 104 105 M Hoechst CD11b/31/45 FITC 105 104 103 –1173 0 102 103 FAPs (lin- PDGFRα+) PDGFRα PeCy7 104 105 M SSC-A 105 104 103 102 –102 50 100 150 200 250 (×1000) –403 0 M e FSC-A e e CD11b/31/45 FITC Relative expression 1.5 1.0 0.5 0.0 Veh TGFβ1 LIF Fβ1+LIF COL1 h Relative expression 2.5 1.5 2.0 1.0 0.5 0.0 Veh TGFβ1 LIF GFβ1+LIF FN g Relative expression Veh TGFβ1 LIF Fβ1+LIF 3 2 1 0 CTGF # φ f h f h g Relative expression 1.5 1.0 0.5 0.0 Veh TGFβ1 LIF TGFβ1+LIF T COL1 k Relative expression 2.5 1.5 2.0 1.0 0.5 0.0 Relative expression 1.5 1.0 0.5 0.0 Relative expression 1.5 1.0 0.5 0.0 T Veh TGFβ1 LIF TGFβ1+LIF Veh TGFβ1 LIF TGFβ1+LIF Veh TGFβ1 LIF TGFβ1+LIF T T CTGF FN COL1 # φ i j k k Fig. 8 Transplantation of CD11b/LIF transgenic BMCs reduces the numbers of FAPs in dystrophic muscle but does not affect phenotype. a QPCR analysis shows that TA muscles from LIF BMT/mdx recipients have reduced Pdgfra gene expression. N = 7 or 8 for WT BMT/mdx and LIF BMT/mdx data sets, respectively, * indicates significantly different from WT BMT/mdx recipients at P < 0.05. P-values based on two-tailed t-test. For all histograms in the figure, the bars indicate mean ± sem. b To quantify the number of FAPs, muscle sections were co-labeled with antibodies to PDGFRα (red) and CD31, CD45 (green). Arrowheads indicate FAPs (CD31-CD45-PDGFRα+). Bar = 50 μm. c Fewer FAPs (CD31-CD45-PDGFRα+) in TA cross-sections of LIF BMT/mdx recipients compared to WT BMT/mdx recipients. N = 5 for each data set. d There was no detectible change in phenotype of PDGFRα+ cells assayed for co-expression of the fibrogenic marker HSP47. e FACS plots demonstrating strategy for sorting FAPs (Hoechst + CD11b-CD31-CD45-PDGFRα+). Fibroblasts derived from FAPs were stimulated with LIF (10 ng/ml) and/or TGFβ1 (10 ng/ml) for 3 h (f–h) or 3 days (i–k) and assayed by QPCR for Ctgf (f, i), Fn1 (g, j), and Col1a1 (h, k). Discussion h l The results of our investigation demonstrate that transplantation of genetically-modified BMCs provides a means to deliver ther- apeutic molecules to dystrophic muscle. In addition, by regulating the expression of the therapeutic transgene with the CD11b promoter, LIF delivery can be modified by the stages of maturation and activation of innate immune cells that differ- entiate from BMCs. This strategy provides a mechanism for the endogenous regulation of transgene expression by the transplant NATURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038/s41467-019-10614-1 | www.nature.com/naturecommunications 10 ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 Relative expression SSC-A 1.5 2.0 1.0 0.5 0.0 105 40 FAPs 5000 4000 3000 2000 1000 0 20 0 (HSP47+/PDGFRα+) ×100 CD31–/CD45–/PDGFRα+ (cells/mm3) WT BMT/mdx LIF BMT/mdx PDGFRα Relative expression Relative expression 2.5 1.5 2.0 1.0 0.5 0.0 ession 2.5 2.0 Relative expression 1.5 1.0 0.5 0.0 ession 1.5 1.0 ession 1.5 Veh TGFβ1 LIF TGFβ1+LIF Veh TGFβ1 LIF TGFβ1+LIF Veh TGFβ1 LIF TGFβ1+LIF 3 2 1 0 CTGF FN COL1 CTGF FN COL1 # φ φ 104 103 102 –102 50 100 150 200 250 (×1000) –403 0 SSC-A 105 104 103 102 –102 –403 0 CD11b/31/45 FITC 105 104 103 –1173 0 M 102 103 104 105 102 103 FAPs (lin- PDGFRα+) PDGFRα PeCy7 104 105 M M a e f g h i j k b c d FSC-A Hoechst Relative expression SSC-A 1.5 2.0 1.0 0.5 0.0 105 40 FAPs 5000 4000 3000 2000 1000 0 20 0 (HSP47+/PDGFRα+) ×100 CD31–/CD45–/PDGFRα+ (cells/mm3) WT BMT/mdx LIF BMT/mdx PDGFRα Relative expression Relative expression 2.5 1.5 2.0 1.0 0.5 0.0 Relative expression 2.5 1.5 2.0 1.0 0.5 0.0 Relative expression 1.5 1.0 0.5 0.0 Relative expression 1.5 1.0 0.5 0.0 Relative expression 1.5 1.0 0.5 0.0 Veh TGFβ1 LIF TGFβ1+LIF Veh TGFβ1 LIF TGFβ1+LIF Veh TGFβ1 LIF TGFβ1+LIF Veh TGFβ1 LIF TGFβ1+LIF Veh TGFβ1 LIF TGFβ1+LIF Veh TGFβ1 LIF TGFβ1+LIF 3 2 1 0 CTGF FN COL1 CTGF FN COL1 # # φ φ 104 103 102 –102 50 100 150 200 250 (×1000) –403 0 SSC-A 105 104 103 102 –102 –403 0 CD11b/31/45 FITC 105 104 103 –1173 0 M 102 103 104 105 102 103 FAPs (lin- PDGFRα+) PDGFRα PeCy7 104 105 M M a e f g h i j k b c d FSC-A Hoechst Fig. 8 Transplantation of CD11b/LIF transgenic BMCs reduces the numbers of FAPs in dystrophic muscle but does not affect phenotype. NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 Source data are provided as a Source Data file stages of the disease1,2,29. In addition to increasing the production of connective tissue proteins, TGFβ can also influence muscle fibrosis by promoting the differentiation of myofibroblasts from muscle55,56 and by increasing the expression of other profibrotic growth factors, especially CTGF53,54. Our finding that LIF reduced or prevented the TGFβ-mediated induction of Ctgf expression in muscle cells may be particularly significant in mdx pathology because reductions in Ctgf expression can significantly slow pathology57. Thus, our in vitro and in vivo data collectively indicate that increases in LIF diminish fibrosis of dystrophic muscle by opposing the profibrotic influence of TGFβ on muscle cells. contrasts with the delivery system we employ, in which elevated LIF production was detectible within inflammatory lesions in dystrophic muscle and pathology was reduced, but LIF remained undetectable in the sera. This indicates that more precise tem- poral and spatial delivery of LIF is necessary for safe and bene- ficial therapeutic application. p pp Exogenous LIF has been reported previously to increase the growth of dystrophic muscle fibers19,20, but we did not observe an effect of the CD11b/LIF transgene on muscle mass or fiber size in transgenic mice or in CD11b/LIF BMT recipients. These differ- ences in outcome may reflect the different modes of LIF delivery, in which increased fiber size resulted from continuous delivery of high concentrations of exogenous LIF19,20. However, we found that transplantation of CD11b/LIF transgenic BMCs affected mdx muscle by decreasing muscle fibrosis, consistent with the treat- ment effect achieved by delivery of exogenous LIF19,20,52. In part, the anti-fibrotic influences of the CD11b/LIF transgene were attributable to modifying the phenotype of satellite cells, reflected in the reduced proportion of satellite cells that expressed detec- tible levels of the collagen chaperone, HSP47, and expressed ERTR7, a connective tissue protein expressed by pro-fibrotic satellite cells40. This is functionally important in the context of DMD pathology because the transition of satellite cells from an HSP47−/ERTR7−to an HSP47+/ERTR7+ phenotype reflects a reduction in their myogenic capacity and an increase in their production of connective tissue proteins that may exacerbate the pathology of muscular dystrophy33 and lead to a reduction in the regenerative capacity of muscle over time40. NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 Mass ratio Total fibers Regen fibers WT BMT/mdx LIF BMT/mdx 2 4000 60 40 20 0 3000 2000 2000 2500 CSA 3 2 1 0 Pax7 MyoD Myogenin Mrf4 1000 1000 1500 500 0 0 Muscle mass/ body mass Fiber X-se area (μm2) Relative expression Fiber number Central nucleated fibers (% total) 1 0 WT BMT/mdx LIF BMT/mdx a b c d e Fig. 9 Transplantation of CD11b/LIF transgenic BMCs does not affect muscle growth or regeneration. Assays of muscle mass to body mass ratio (a), fiber number (b), proportion of centrally-nucleated regenerating fibers (c), and muscle fiber cross-sectional area (d) indicate no difference in muscle growth or regeneration between WT BMT/mdx and LIF BMT/mdx recipients. N = 5 per group. For all histograms in the figure, the bars indicate mean ± sem. e QPCR analysis shows no difference in the expression of myogenic transcription factors (Pax7, Myod1, Myog, and Mrf4) in WT BMT/mdx versus LIF BMT/mdx recipients. N = 7 or 8 for WT BMT/mdx and LIF BMT/mdx data sets, respectively. No significant differences were identified between groups at P < 0.05, determined by two-tailed t-test. Source data are provided as a Source Data file Mass ratio 2 Muscle mass/ body mass 1 0 a Total fibers 4000 3000 2000 1000 0 Fiber number b Regen fibers WT BMT/mdx LIF BMT/mdx 60 40 20 0 Central nucleated fibers (% total) c b a c 2000 2500 CSA 1000 1500 500 0 Fiber X-se area (μm2) d 3 2 1 0 Pax7 MyoD Myogenin Mrf4 Relative expression WT BMT/mdx LIF BMT/mdx e d e Fig. 9 Transplantation of CD11b/LIF transgenic BMCs does not affect muscle growth or regeneration. Assays of muscle mass to body mass ratio (a), fiber number (b), proportion of centrally-nucleated regenerating fibers (c), and muscle fiber cross-sectional area (d) indicate no difference in muscle growth or regeneration between WT BMT/mdx and LIF BMT/mdx recipients. N = 5 per group. For all histograms in the figure, the bars indicate mean ± sem. e QPCR analysis shows no difference in the expression of myogenic transcription factors (Pax7, Myod1, Myog, and Mrf4) in WT BMT/mdx versus LIF BMT/mdx recipients. N = 7 or 8 for WT BMT/mdx and LIF BMT/mdx data sets, respectively. No significant differences were identified between groups at P < 0.05, determined by two-tailed t-test. Discussion h l N = 4 technical replicates for each data set. Significant findings were verified with biological replicates of cells sorted from independent donors. * Indicates significantly different from control cultures, # indicates significantly different from TGFβ1 treated cultures, and Φ indicates significantly different from LIF-treated cultures at P < 0.05. P-values based on ANOVA with Tukey’s multiple comparison test. Source data are provided as a Source Data file 11 11 NATURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038/s41467-019-10614-1 | www.nature.com/naturecommunications ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 Some of the immunomodulatory effects achieved by trans- plantation of CD11b/LIF transgenic cells reflect the effects of transgene expression within the diseased muscle. For example, Socs3 expression was significantly elevated in muscles of mice that received CD11b/LIF BMT, although expression of the transgene in macrophages in vitro did not affect the expression of Socs3. LIF can increase Socs3 expression in multiple cell types62 and elevated expression or activity of Socs3 in macrophages can strongly influence their phenotype and cytokine production. In vivo models of inflammation show that siRNA-silencing of SOCS3 or targeted deletion of SOCS3 in macrophages can either promote63 or oppose64 the M1-biased phenotype. In experimental perito- nitis, SOCS3 mRNA silencing in macrophages caused elevated expression of the M2 phenotypic markers Il10, Mrc1, and Arg164, which is consistent with the inverse relationship we observed between elevated Socs3 expression in CD11b/LIF BMT recipients and reduced expression of Il10, Arg2, and Mrc1. Together, these observations suggest that the shift of CD11b/LIF macrophages away from an M2-biased phenotype in mdx BMT recipients may result, in part, from LIF induction of Socs3 after the transgenic macrophages enter the diseased muscle. However, some of the treatment effects that we observed may have resulted from immunomodulatory roles of the transgene that occurred before their invasion into the pathological muscle. Our finding that isolated BMCs from CD11b/LIF mice showed greatly reduced levels of Cd163 and Arg1 expression as they differentiated to macrophages in vitro shows that some autocrine influences of the transgene on macrophage gene expression do not require locali- zation of the cells in the dystrophic muscle. This contrasts with the reduced expression of TGFβ in intramuscular macrophages of CD11b/LIF BMT recipients that did not occur in transgenic macrophages in vitro. The reduction in arginase expression in CD11b/LIF transgenic macrophages may be particularly impor- tant in the pathophysiology of muscular dystrophy because arginine metabolism by arginase increases proline production which is necessary for collagen synthesis and contributes sig- nificantly to increased fibrosis in mdx muscles during progressive stages of pathology23. p p yp Collectively, our findings show that expression of a CD11b/LIF transgene in BMDCs can disrupt multiple processes that con- tribute to fibrosis of dystrophic muscle, including affecting macrophage recruitment, phenotype and production of pro- fibrotic cytokines and enzymes, in addition to preventing the fibrogenic conversion of satellite cells and reducing numbers of FAPs (Fig. 10). NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 Monocytes/ macrophages LIF LIF LIF LIF FAPs Intramuscular macrophages Pro-fibrotic macrophages 2 1 3 4 Increased arginase expression Increased TGFβ expression Myogenic muscle cells Fibrogenic muscle cells Fibrosis Fibrosis Fibrosis Fig. 10 Potential immunomodulatory and anti-fibrotic actions of LIF expressed by the CD11b/LIF transgene in muscular dystrophy. (1) LIF can serve an immunomodulatory role by reducing the expression of Ccl2 in macrophages, which is associated with reduced recruitment of monocytes/macrophages into dystrophic muscle. (2) LIF can serve an immunomodulatory role by reducing the activation of monocytes/macrophages to a CD163+, M2-biased phenotype that can increase fibrosis of dystrophic muscle. (3) LIF can reduce the expression of the pro-fibrotic molecules Arg1 and Tgfb1 in macrophages. (4) LIF can reduce the TGFβ1-mediated induction of pro-fibrotic genes in muscle cells, including Ctgf and Col1a1 Monocytes/ macrophages Increased TGFβ expression Fig. 10 Potential immunomodulatory and anti-fibrotic actions of LIF expressed by the CD11b/LIF transgene in muscular dystrophy. (1) LIF can serve an immunomodulatory role by reducing the expression of Ccl2 in macrophages, which is associated with reduced recruitment of monocytes/macrophages into dystrophic muscle. (2) LIF can serve an immunomodulatory role by reducing the activation of monocytes/macrophages to a CD163+, M2-biased phenotype that can increase fibrosis of dystrophic muscle. (3) LIF can reduce the expression of the pro-fibrotic molecules Arg1 and Tgfb1 in macrophages. (4) LIF can reduce the TGFβ1-mediated induction of pro-fibrotic genes in muscle cells, including Ctgf and Col1a1 characteristic of type 2 immunity; much of the lethality of DMD is attributable to fibrosis of cardiac and respiratory muscles. Thus, by modulating the numbers and phenotype of macrophages in dystrophic muscle, LIF can produce broad effects on muscle pathology. established that signaling through CCR2 is a primary mechanism for recruiting macrophages to diseased or injured muscle by showing that blockade or deletion of CCR2 greatly reduces macrophage entry into injured muscle27,45,47. We found that CD11b/LIF BMT decreased expression of CCR2 ligands in muscle and reduced the numbers of macrophages that expressed CCL2. Those reductions were also associated with large reductions in total numbers of F4/80+ intramuscular macrophages, including CD206+ and CD163+ macrophages. Thus, much of the anti- inflammatory effect of the transgene may occur through disrup- tion of CCR2-mediated signaling, leading to reduced numbers of intramuscular macrophages and impairing their activation to a pro-fibrotic, M2-biased phenotype. NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 The observation that the CD11b/LIF BMT reduced TGFβ1 expression in intramuscular macrophages without causing reductions in total TGFβ1 expression in whole muscle also indicates the specificity of targeting treatment effects that are achieved by the CD11b/LIF transgene. This may provide advan- tages over other experimental and therapeutic approaches that have been explored previously to reduce fibrosis of dystrophic muscle by inhibiting TGFβ1 expression or activity through pharmacological approaches1,3,58,59. While those pharmacologi- cal approaches are technically straight-forward and effective at reducing fibrosis in dystrophic muscle, their systemic adminis- tration does not provide delivery specifically to sites of inflam- mation, and increases the risks of off-target effects. Although CD11b/LIF BMT reduced pathological changes in satellite cells, we found that some beneficial effects of CD11b/LIF transgenic cells are attributable to modulation of the inflamma- tory response, rather than direct actions on muscle (Fig. 10). Despite the fact that DMD and mdx dystrophy result from mutations that cause loss of the membrane-associated structural protein, dystrophin, and lead to a mechanically-weaker muscle cell membrane60,61, most muscle fiber damage results from lysis caused by myeloid cells, especially macrophages expressing inducible nitric oxide synthase (iNOS) that are biased toward the M1, pro-inflammatory phenotype7,26. However, as the disease progresses, macrophages in dystrophic muscle shift to a CD163 +/CD206+ phenotype that increases muscle fibrosis23 and is g p y Although the CD11b/LIF transgene reduced the expression of pro-fibrotic molecules by muscle cells in CD11b/LIF BMT reci- pients in vivo, LIF did not reduce the basal level of expression of genes encoding connective tissue proteins by muscle cells in vitro. Instead, we found that LIF reduced the activation of pro-fibrotic genes in myoblasts that was induced by the cytokine TGFβ. TGFβ has broad, profibrotic effects by increasing the expression of major, connective tissue proteins, including collagen and fibronectin53,54, and reductions in TGFβ can significantly decrease fibrosis of dystrophin-deficient muscle, at least at early TURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038/s41467-019-10614-1 | www.nature.com/naturecommunications 12 ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 However, we believe that the more broadly- significant finding in our investigation is that our data show that genetically-modified BMCs can be used as vectors to deliver therapeutic genes to dystrophic muscle. This approach is applicable not only to LIF, but may provide a more specific tar- geting strategy for the numerous gene products that have been previously identified as potentially-useful, therapeutic molecules for DMD. ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 488 (1:200, 30 min at RT, Abcam, #ab102260) and horse anti-rabbit IgG Dylight 594 (1:200, 30 min at RT, Vector, #DI-1094) or horse anti-goat IgG Dylight 594 (1:200, 30 min at RT, Vector, #DI-3094). Sections were then washed with PBS and mounted with Prolong Gold mounting media (Invitrogen). line is maintained as hemizygous to produce transgenic mice and wild-type, littermate controls for experimentation. Mice were randomly allocated to experimental groups. WT or CD11b/LIF BMCs were transplanted into mdx mice assigned non-sequential identification numbers. Investigators collecting data and performing analysis were aware of animal numbers only and were blinded to treatment groups. g g g For identification of CCR2+ macrophages, sections were fixed with 4% PFA for 10 min and then incubated with blocking buffer for 1 h. Sections were then labeled with rabbit anti-mouse CCR2 (1:50, Abcam, clone E68) and rat anti-mouse CD68 or rat anti-mouse CD206 at 4 °C overnight. Sections were washed with PBS and then incubated with donkey anti-rat IgG Dylight 594 (1:200, 30 min at RT, Abcam, #ab102262) and horse anti-rabbit IgG Dylight 488 (1:200, 30 min at RT, Vector, #DI-1088). CD11b/LIF mdx transgenic mice were produced by crossing CD11b/LIF hemizygous males with mdx females to generate CD11b/LIF hemizygous, transgenic mice that were also dystrophin-deficient (CD11b/LIF mdx). Dystrophin- deficient status was verified by ARMS PCR screening65 and presence of the hCD11b/LIF construct was determined as described above. The CD11b/LIF mdx mice were backcrossed with wild-type mdx mice for 7 generations to produce CD11b/LIF mdx mice that were dystrophin-deficient and either hemizygous or wild-type controls for the CD11b/LIF transgene. For identification of fibrogenic satellite cells, sections were fixed in 2% paraformaldehyde for 10 min. Slides were then immersed in antigen retrieval buffer (10 mM sodium citrate, 0.05% Tween-20, pH 6) at 95–100 °C for 40 min, except for sections undergoing Pax7/Ertr7 co-labeling this step was omitted. Sections were then treated with blocking buffer from a mouse-on-mouse immunohistochemistry kit (M.O.M. kit; Vector) for 1 h and immunolabeled with mouse anti-Pax7 and rabbit anti-HSP47 (1:200, Abcam, #77609) or anti-Ertr7 (1:1000, SCBT, #SC- 73355) overnight at 4 °C. Anti-Pax7 was purified from hybridoma cell supernatant (Developmental Studies Hybridoma Bank, Iowa City, Iowa)68. Sections were washed with PBS and then incubated with horse anti-mouse IgG Dylight 594 (1:200, 30 min at RT, Vector, DI-2594) and horse anti-rabbit IgG Dylight 488 (1:200, 30 min at RT). ARTICLE The number of cells per volume of muscle was determined by mea- suring the total volume of each section using a stereological, point-counting technique to determine section area and then multiplying that value by the section thickness (10 μm)7. The numbers of immunolabeled cells in each section were counted and expressed as the number of cells per unit volume of each section. RNA was isolated from FACS sorted cells by first sorting cells directly into Buffer RLT RNA lysis buffer (Qiagen). RNA was isolated using a Qiagen RNeasy Micro Kit according to the manufacturer’s protocol. RNA yield was quantified using a BioDrop μLite. RNA (50 ng/reaction) was reverse transcribed using a qScript XLT cDNA Supermix (QuantaBio). QPCR experiments were performed on a QuantStudio 5 Real-Time PCR System (Thermo Fisher) with PerfeCTa SYBR Green Supermix, Low Rox (QuantaBio)13. Assays for fiber number, central nucleation, and size. TA muscles were sec- tioned at the midbelly of muscles and used for fiber cross-sectional area mea- surements5. The proportion of fibers containing central nuclei, an indicator of fiber regeneration, was also determined. Central-nucleation was expressed as the ratio of central nucleated fibers relative to the entire population of fibers sampled for each muscle. The cross-sectional areas of >300 muscle fibers were measured using a digital imaging system (BioQuant). Immunohistochemistry. Muscles dissected from euthanized mice were frozen in liquid nitrogen-cooled isopentane. Cross-sections 10-µm thick were taken from the mid-belly of muscles and fixed in ice-cold acetone or 2% paraformaldehyde for 10 min. Endogenous peroxidase activity in the sections was quenched by immersion in 0.3% H2O2. Most sections were blocked for 1 h with blocking buffer (3% bovine serum albumin (BSA), 2% gelatin, and 0.05% Tween-20 in 50 mM Tris–HCl pH 7.6 containing 150 mM NaCl). Alternatively, sections were incubated with 10% horse serum in PBS with 0.1% Tween-20 or mouse-on-mouse blocking reagent (M.O.M. kit; Vector) for sections to be incubated with primary antibodies from goat or mouse origin, respectively. ARTICLE Sections were then incubated with: rat anti-mouse F4/80 (1:100, overnight at 4 °C, eBioscience, clone BM8), rat anti-mouse CD68 (1:100, 3 h at room temperature (RT), AbD Serotec, clone FA-11), rabbit anti-mouse CD163 (1:100, 3 h at RT, Santa Cruz Biotech, clone M-96), rat anti-mouse CD206 (1:50, 3 h at RT, AbD Serotec, clone MR5D3), rat anti-CD4 (1:25, overnight at 4 °C, Biolegend, clone GK1.5), rat anti-Ly-6B.2 (1:25, 2 h at RT, Bio-Rad, clone 7/4), rabbit anti-collagen type 1 (1:50, 3 h at RT, Chemicon, #AB745), goat anti-collagen type 3 (1:50, 3 h at RT, Southern Biotech #1330-01), goat anti-collagen type 5 (1:50, overnight at 4 °C, Southern Biotech, #1350-01), goat anti-LIF (1:66, overnight at 4 ° C, R&D Systems, #AB-449), and mouse anti-developmental myosin heavy chain (1:100, overnight at 4 °C, Novacastra, #106304). The sections were washed with phosphate buffered saline (PBS) and probed with biotin-conjugated secondary antibodies (1:200, 30 min at RT, Vector Laboratories). Sections were then washed with PBS and incubated with avidin D-conjugated HRP (1:1000, 30 min at RT, Vector). Staining was visualized with the peroxidase substrate, 3-amino-9- ethylcarbazole (Vector). Assay of muscle connective tissue content. The volume fraction of muscle that was occupied by collagen types 1, 3, and 5 was determined by overlaying a 10 × 10 eye-piece grid on microscopic images of cross-sections of entire muscle that were immunolabeled with antibodies to collagen types 1, 3, or 5. Assay of muscle connective tissue content. The volume fraction of muscle that was occupied by collagen types 1, 3, and 5 was determined by overlaying a 10 × 10 eye-piece grid on microscopic images of cross-sections of entire muscle that were immunolabeled with antibodies to collagen types 1, 3, or 5. Preparation of BMMCs and BMDMs. BMMCs were separated from whole BMC preparations flushed from WT or CD11b/LIF femurs and tibiae and separated using a histopaque-1077 gradient (Sigma). The freshly-isolated BMMCs were then used for RNA isolation and analysis. For preparation of BMDMs, BMCs were aseptically flushed from WT or CD11b/LIF femurs and tibiae and differentiated in vitro to BMDMs24. BMDMs were stimulated for 24 h with activation media consisting of Dulbecco’s Modified Eagle Medium (DMEM) with 0.25% heat- inactivated fetal bovine serum (FBS; Omega), 100 U/ml penicillin, 100 µg/ml streptomycin (1% P/S), and 10 ng/ml macrophage colony stimulating factor (MCSF; R&D). ELISA analysis of BMDM conditioned media. ARTICLE Bone marrow transplantation. Beginning 1 week prior to BMT, mouse drinking water was supplemented with trimethoprim/sulfamethoxazole (80 μg/ml tri- methoprim and 400 μg/ml sulfamethoxazole) and continued for 3 weeks. Two- month-old female mdx mice underwent myeloablative preconditioning via intra- peritoneal injections of 1,4-butanediol dimethanesulfonate (Sigma-Aldrich) (20 mg/kg body weight) 72-, 48-, and 24-h prior to BMT. On the day of transplan- tation, male WT and CD11b/LIF donor mice were euthanized and their femur and tibia bones were sterilely dissected and flushed of BMCs. BMCs were isolated and recipient mice received 107 donor BMCs by tail-vein injection. At 4 months post- BMT, tissues and BMCs were collected from recipient mice. BMCs were used for chimerism analysis by fluorescent in situ hybridization of the Y-chromosome (Kreatech FISH Probes). For identification of FAPs, sections were fixed in ice-cold acetone for 10 min and then incubated with blocking buffer for 1 h. Sections were then labeled with rat anti-mouse CD31 conjugated with FITC (1:50, eBioscience, clone 390), rat anti- mouse CD45 conjugated with FITC (1:100, eBioscience, clone 30-F11), and goat anti-PDGFRα (1:100, R&D Systems, #AF1062) at 4 °C overnight. Sections were washed with PBS and then incubated with horse anti-goat IgG Dylight 594 (1:200, 30 min at RT, Vector). RNA isolation and QPCR. RNA was isolated from muscle homogenates and reverse transcribed to produce cDNA24. QPCR experiments were designed using established guidelines for experimental design, data normalization and data ana- lysis to maximize the rigor of quantifying the relative levels of mRNA13,66,67. The expression for each gene in control samples was set to 1 and the other expression values were then scaled to that value. PCR primers are listed in Supplementary Table 1. For identification of fibrogenic PDGFRα+ cells, sections were fixed in ice-cold acetone for 10 min and then incubated with blocking buffer for 1 h. Sections were then labeled with rabbit anti-mouse HSP47 (1:100, ABcam, clone EPR4217) and goat anti-PDGFRα at 4 °C overnight. Sections were washed with PBS and then incubated with horse anti-goat IgG Dylight 594 (1:200, 30 min at RT) and horse anti-rabbit IgG Dylight 488 (1:200, 30 min at RT). Cultured cells were washed twice with ice-cold DPBS and collected in Trizol (Invitrogen). RNA was extracted and isolated with chloroform extraction and isopropyl alcohol precipitation, followed by clean-up with an RNA Clean and Concentrator Kit (Zymo Research). Total RNA was quantified, reverse transcribed, and used for QPCR13. Stereology. Methods Mi ll Mice. All experimentation complied with all relevant ethical regulations for animal testing and research, and the study protocol was approved by the Chancellor’s Animal Research Committee at the University of California, Los Angeles. C57BL/ 10ScSn-Dmdmdx/J mice (mdx mice) were purchased from The Jackson Laboratory (Bar Harbor, ME) and bred in pathogen-free vivaria. Mdx mice were selected for use in these experiments instead of more rapidly progressive models of DMD because the goal of our investigation is to test our hypothesis that transplantation of genetically-modified BMCs provides a novel therapeutic strategy for muscular dystrophy. If we used a rapidly, progressive mouse model, such as the mdx/utr− mouse line in which the mice die at 2–3 months of age, we would be unable to assay for treatment effects achieved by bone marrow transplantation because the mice would die before enough time passed for sufficient BMC engraftment and then for the transplanted cells to mediate their therapeutic effects. In preparation for generating CD11b/LIF mice, the complete Mus musculus LIF cDNA sequence (611-bp; NM_008501) was amplified by PCR and ligated into a pGL3-Basic vector (Promega) at the Nco I/Xba I sites. The pGL3-Basic vector contained a 550-bp fragment of the human CD11b promoter at the Hind III site, upstream of the LIF insertion site. The 1215-bp, hCD11b/LIF fragment was isolated from pGL3-Basic by restriction endonuclease digestion with Xho I/Xba I and used for pronuclear injection into CB6F1 eggs to generate transgenic mice. Positive founders were identified by PCR screening for presence of the hCD11b/LIF construct and backcrossed with C57BL/6J mice for 7 generations. The hCD11b/LIF g p gy The immunomodulatory influences of the transgene extend beyond autocrine effects on macrophage phenotype, because the muscles of CD11b/LIF BMC recipients showed large reductions in the expression of ligands for CCR2. Previous investigators 13 NATURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038/s41467-019-10614-1 | www.nature.com/naturecommunications ARTICLE ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 concentration of each cytokine was determined by comparing the optical density of the samples to the standard curve. concentration of each cytokine was determined by comparing the optical density of the samples to the standard curve. fiber length (Lf). To measure elasticity, the muscle was left unstimulated while the lever arm oscillated at ±20% of the Lf for 20 s. Muscles were allowed to rest for 60 s before subsequent oscillation series. Muscles were allowed to rest for 60 s before a series of oscillations at 3 Hz, which provides a physiological strain and strain rate70. Dynamic Muscle Control and Dynamic Muscle Analysis (Aurora Scientific) soft- ware was used to conduct experiments and record data. Force measurements were normalized to muscle cross-sectional area, and position measurements were nor- malized to percent of Lf. fiber length (Lf). To measure elasticity, the muscle was left unstimulated while the lever arm oscillated at ±20% of the Lf for 20 s. Muscles were allowed to rest for 60 s before subsequent oscillation series. Muscles were allowed to rest for 60 s before a series of oscillations at 3 Hz, which provides a physiological strain and strain rate70. Dynamic Muscle Control and Dynamic Muscle Analysis (Aurora Scientific) soft- ware was used to conduct experiments and record data. Force measurements were normalized to muscle cross-sectional area, and position measurements were nor- malized to percent of Lf. ELISA analysis of serum. Whole blood was collected from the femoral artery and allowed to clot on ice for at least 30 min. The whole blood was spun for 10 min at 2000×g at 4 °C. The serum was collected and stored in liquid nitrogen until ana- lyzed for circulating LIF, TNFα, IFNγ, IL-4, and IL-10 by ELISA, according to manufacturer’s instructions (R&D Systems, Quantikine ELISAs, #MLF00, MTA00B, MIF00, M4000B, and M1000B). Each group contained 3 replicates. Statistical analyses. All data are presented as mean ± sem. Statistical significance was calculated using unpaired Student’s t-tests or ordinary one-way ANOVA with Tukey’s multiple comparison test to determine differences among multiple groups. Differences with a P-value < 0.05 were considered statistically significant. The equality of variance between the groups that are being compared was tested with an F test, experiments with a P-value < 0.05 are denoted in the figure legend. Addi- tionally, for immunohistochemistry and immunofluorescence experiments, slides were only included if concurrently immunolabeled. References 1. Nelson, C. A. et al. Inhibiting TGF-β activity improves respiratory function in mdx mice. Am. J. Pathol. 178, 2611–2621 (2011). 2. Andreetta, F. et al. Immunomodulation of TGF-beta 1 in mdx mouse inhibits connective tissue proliferation in diaphragm but increases inflammatory response: implications for antifibrotic therapy. J. Neuroimmunol. 175, 77–86 (2006). MPCs were isolated from 14-months-old CD11b/LIF mdx mice and littermate controls. Hindlimb and forelimb muscles were dissected and digested as described for FAPs isolation. Isolated cells were resuspended in staining buffer with CD16/32 for 10 min to block Fc receptor binding. Cells were labeled with cell impermeant dye DAPI (Sigma) to distinguish live cells and antibodies against CD11b, CD31, and CD45 conjugated with FITC and Sca-1 conjugated with PE-Cy5 (eBioscience #15-5981; 0.2 µg/test), integrin α7 conjugated with PE (Medical and Biological Laboratories #K0046-5; 15 µl/test). Live MPCs (DAPI-CD11b/31/45-Sca1-α7int+) were sorted into Buffer RLT RNA lysis buffer (Qiagen) using a FACSAriaIII high speed cell sorter. 3. Taniguti, A. P. T., Pertille, A., Matsumura, C. Y., Santo Neto, H. & Marques, M. J. Prevention of muscle fibrosis and myonecrosis in mdx mice by suramin, a TGF-β1 blocker. Muscle Nerve 43, 82–87 (2011). 4. Bogdanovich, S. et al. Functional improvement of dystrophic muscle by myostatin blockade. Nature 420, 418–421 (2002). myostatin blockade. Nature 420, 418–421 (2002). 5. Wehling-Henricks, M. et al. Klotho gene silencing promotes pathology in the mdx mouse model of Duchenne muscular dystrophy. Hum. Mol. Genet. 25, 2465–2482 (2016). 6. Straub, V., Rafael, J. A., Chamberlain, J. S. & Campbell, K. P. Animal models for muscular dystrophy show different patterns of sarcolemmal disruption. J. Cell Biol. 139, 375–385 (1997). Primary fibroblast cell culture. Sorted FAPs were cultured in growth medium (DMEM, 20% FBS, 10% heat-inactivated horse serum, 1% P/S and 2.5 ng/ml bFGF) on tissue culture plates coated with Matrigel41. After plating, cells were cultured for 3 days and half the medium was changed. Cells were expanded and subcultured. Prior to stimulation, cells were cultured in reduced serum media overnight (DMEM, 2% FBS, 1% P/S, and 2.5 ng/ml bFGF). Fibrogenic cell cultures were stimulated with vehicle, TGFβ1 (10 ng/ml), LIF (10 ng/ml), or TGFβ1 + LIF for 3 h or 3 days (with media changes at 24- and 48-h). 7. Wehling, M., Spencer, M. J. & Tidball, J. G. A nitric oxide synthase transgene ameliorates muscular dystrophy in mdx mice. J. Cell Biol. 155, 123–131 (2001). 8. Spencer, M. Data availability Th h d l h The authors declare that the data supporting the findings of this study are available within the paper and its Supplementary Information files. The source data pertaining to Figs. 1a–c, 2a, d, f, g, i, j, m, p–r, 3a, b, e, h, k, l, 4a–f, h, 5g, j, k, 6a, d, e, 7c–f, 9a–d, f and Supplementary Figs. 1a, 1b, 1c, 1d, 2a, 2b, 3a, 3b, 3c, 3d, 4a, 4b, 4c, 5b, 5c, 5d, 5e, and 5f are provided as a Source Data file. Received: 22 June 2018 Accepted: 22 May 2019 ARTICLE Statistical analysis was per- formed using GraphPad Prism. Assays for LIF effects on muscle cell fibrogenesis. The C2C12 cell line was purchased from American Type Culture Collection (ATCC CRL-1772 cell line). The cells were authenticated as myoblasts by confirming their differentiation into contractile myotubes that express characteristic muscle proteins. Cells were seeded in six-well plates at 6 × 104 cells per well and cultured in DMEM containing 10% FBS, 1% P/S at 37 °C in 5% CO2 for 24 h and then serum-starved overnight prior to stimulation. To generate myotubes, myoblasts were grown to 90% confluence and then differentiated in serum-free DMEM for 24 h. The cells were then returned to DMEM containing 10% FBS for 5 days. Myoblast and myotube cultures were stimulated with vehicle, TGFβ1 (10 ng/ml), LIF (10 ng/ml), or TGFβ1 + LIF for 3- or 24-h. Reporting summary. Further information on research design is available in the Nature Research Reporting Summary linked to this article. FAPs and myogenic progenitor cell preparation and isolation. FAPs were iso- lated from 6-month-old WT mice. Hindlimb and forelimb muscles were dissected and rinsed in DMEM. Muscles were minced and digested in 5 ml of enzyme buffer (DMEM, 25 mM HEPES (Sigma), 5 mM MgCl2 (Fisher), 2% P/S, 12.5 U dispase, type II, 12.5 U collagenase B, and 20 μg/ml DNase I (Roche)) for 60 min at 37 °C with gentle trituration. The digestion was neutralized with 2 volumes of staining buffer (DMEM, 10 mM NaHCO3 (EMD Millipore), 25 mM HEPES, 5 mM EDTA, 5 mM MgCl2, 1 mM L-glutamine, 2% BSA, and 2% P/S). The digestate was passed through 100 μm mesh filters and cells were pelleted at 350g for 5 min. Cells were resuspended in ACK lysis buffer (Lonza) for 5 min followed by the addition of an equal volume of staining buffer and cells were pelleted at 350g for 5 min. Cells were resuspended in staining buffer with CD16/32 (eBioscience #14-0161-85; 0.5 µg/test) for 10 min to block Fc receptor binding. Cells were labeled with Hoechst (Sigma #14533) and antibodies against CD11b (eBioscience #11-0112; 0.25 µg/test), CD31 (eBioscience #11-0311; 0.5 µg/test) and CD45 (eBioscience #11-0451; 0.1 µg/test) conjugated with FITC and PDGFRα conjugated with PE-Cy7 (eBioscience #25- 1401; 0.2 µg/test). FAPs (Hoechst + CD11b/31/45-PDGFRα+) were sorted into collection buffer (DMEM, 10 mM NaHCO3 and 20% FBS) using a BD SORP FACSAriaII cell sorter. References J., Walsh, C. M., Dorshkind, K. A., Rodriguez, E. M. & Tidball, J. G. Myonuclear apoptosis in dystrophic mdx muscle occurs by perforin- mediated cytotoxicity. J. Clin. Invest. 99, 2745–2751 (1997). 9. Spencer, M. J., Montecino-Rodriguez, E., Dorshkind, K. & Tidball, J. G. Helper (CD4(+)) and cytotoxic (CD8(+)) T cells promote the pathology of dystrophin-deficient muscle. Clin. Immunol. 98, 235–243 (2001). Physiological analysis. We assayed muscle stiffness and viscoelasticity at 14 months of age because connective tissue accumulation in mdx muscle is pro- gressive between 3 and 24 months of age. We expected that if we sampled for effects of the transgene on muscle stiffness during the late, progressive stage of the disease, the magnitude of the effect would be greater, which would enable us to address more definitively the question of whether the transgene influenced muscle stiffness. Male WT/mdx and LIF/mdx mice were anesthetized by the intraper- itoneal (i.p.) injection of ketamine (40 mg/kg body weight). Anesthesia was checked by testing mice for a positive reflex response to a hind foot pinch and by mon- itoring respiration. Additional i.p. injections of ketamine were given throughout the study, as needed. For in-situ analysis of the TA muscle the knee was immo- bilized to the heated (37 °C) platform of an 809C in-situ mouse apparatus (Aurora Scientific). Silk sutures (5-0; Ethicon) were knotted to the distal, severed tendon and then secured to the lever arm of a dual-mode force transducer-servomotor (Aurora Scientific, Model 305C-5N). After placing platinum-tipped electrodes into the leg above the knee, flanking the sciatic nerve, the TA muscle was stimulated by pulses and manipulated on three axes to find the optimal muscle length (Lo). Lo was multiplied by the pennation of 0.6 for the TA muscle69 to determine optimal 10. Cai, B., Spencer, M. J., Nakamura, G., Tseng-Ong, L. & Tidball, J. G. Eosinophilia of dystrophin-deficient muscle is promoted by perforin-mediated cytotoxicity by T cell effectors. Am. J. Pathol. 156, 1789–1796 (2000). 11. Hodgetts, S., Radley, H., Davies, M. & Grounds, M. D. Reduced necrosis of dystrophic muscle by depletion of host neutrophils, or blocking TNFalpha function with Etanercept in mdx mice. Neuromuscul. Disord. 16, 591–602 (2006). 12. Gorospe, J. R., Nishikawa, B. K. & Hoffman, E. P. Recruitment of mast cells to muscle after mild damage J Neurol Sci 135 10 17 (1996) 11. Hodgetts, S., Radley, H., Davies, M. & Grounds, M. D. NATURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038/s41467-019-10614-1 | www.nature.com/naturecommunicatio ARTICLE Cultures of BMDM from WT mice were established as described above. On the 6th day of culture, the BMDMs were switched to DMEM containing 1% P/S, 0.25% heat-inactivated FBS, and M-CSF or media containing 10 ng/ml recombinant mouse LIF (eBioscience) (stimulation media). After 24 h of stimulation, conditioned media (CM) were collected, briefly centrifuged to remove particulates and then frozen at −20 °C. Separate aliquots of BMDM CM from each sample were analyzed for expression of CCL2 (Duoset ELISA, R&D Systems, #DY479) and TGFβ (Emax immunoassay; Promega, #G7590), according to manufacturer’s instructions. Following an HRP-based reaction, a colored product was formed in proportion to the amount of cytokine present, which was analyzed by a spectrophotometer (Bio-Rad Benchmark Microplate Reader) at a wavelength of 450 nm with a 540 nm correction. The Immunofluorescence. For co-labeling of macrophages, sections were fixed in ice- cold acetone for 10 min and then incubated in blocking buffer for 1 h. Sections were then incubated with rat anti-F4/80 and goat anti-CCL2 (1:50, R&D Systems, AB-479-NA) or rabbit anti-TGFβ1 (1:100, Abcam, #ab92486) overnight at 4 °C. Sections were washed with PBS and then incubated with donkey anti-rat Dylight 14 TURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038/s41467-019-10614-1 | www.nature.com/naturecommunications ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 15. Todd, R. F., Nadler, L. M. & Schlossman, S. F. Antigens on human monocytes identified by monoclonal antibodies. J. Immunol. 126, 1435–1442 (1981). 43. Mueller, A. A., van Velthoven, C. T., Fukumoto, K. D., Cheung, T. H. & Rando, T. A. Intronic polyadenylation of PDGFRα in resident stem cells attenuates muscle fibrosis. Nature 540, 276–279 (2016). y 16. Griffin, J. D., Ritz, J., Nadler, L. M. & Schlossman, S. F. Expression of myeloid differentiation antigens on normal and malignant myeloid cells. J. Clin. Invest. 68, 932–941 (1981). 44. Tidball, J. G. & Wehling-Henricks, M. Macrophages promote muscle membrane repair and muscle fibre growth and regeneration during modified muscle loading in mice in vivo. J. Physiol. 578, 327–336 (2007). 17. Rosmarin, A. G. et al. Differential expression of CD11b/CD18 (Mo1) and myeloperoxidase genes during myeloid differentiation. Blood 73, 131–136 (1989). g J y , ( ) 45. Shireman, P. K. et al. MCP-1 deficiency causes altered inflammation with impaired skeletal muscle regeneration J Leukoc Biol 81 775 785 (2007) g y 45. Shireman, P. K. et al. MCP-1 deficiency causes altered inflammation with impaired skeletal muscle regeneration. J. Leukoc. Biol. 81, 775–785 (2007). p g ( ) 46. Segawa, M. et al. Suppression of macrophage functions impairs skeletal muscle regeneration with severe fibrosis. Exp. Cell Res. 314, 3232–3244 (2008). 18. Robertson, T. A., Maley, M. A., Grounds, M. D. & Papadimitriou, J. M. The role of macrophages in skeletal muscle regeneration with particular reference to chemotaxis. Exp. Cell Res. 207, 321–331 (1993). 47. Martinez, C. O. et al. Regulation of skeletal muscle regeneration by CCR2- activating chemokines is directly related to macrophage recruitment. Am. J. Physiol. Regul. Integr. Comp. Physiol. 299, R832–R842 (2010). p 19. Kurek, J., Bower, J., Romanella, M. & Austin, L. Leukaemia inhibitory factor treatment stimulates muscle regeneration in the mdx mouse. Neurosci. Lett. 212, 167–170 (1996). 48. Ball, L. M. et al. Paediatric allogeneic bone marrow transplantation for homozygous beta-thalassaemia, the Dutch experience. Bone Marrow Transpl. 31, 1081–1087 (2003). 20. Austin, L. et al. Leukemia inhibitory factor ameliorates muscle fiber degeneration in the mdx mouse. Muscle Nerve 23, 1700–1705 (2000). 49. Reuter, U. et al. Correction of complete interferon-gamma receptor 1 deficiency by bone marrow transplantation. Blood 100, 4234–4235 (2002). 21. Hunt, L. C., Upadhyay, A., Jazayeri, J. A., Tudor, E. M. & White, J. D. ARTICLE An anti- inflammatory role for leukemia inhibitory factor receptor signaling in regenerating skeletal muscle. Histochem. Cell Biol. 139, 13–34 (2013). 50. Metcalf, D. & Gearing, D. P. Fatal syndrome in mice engrafted with cells producing high levels of the leukemia inhibitory factor. Proc. Natl. Acad. Sci. USA 86, 5948–5952 (1989). g g 22. Sica, A. & Mantovani, A. Macrophage plasticity and polarization: in vivo veritas. J. Clin. Invest. 122, 787–795 (2012). 51. Metcalf, D. & Gearing, D. P. A myelosclerotic syndrome in mice engrafted with cells producing high levels of leukemia inhibitory factor (LIF). Leukemia 3, 847–852 (1989). 23. Wehling-Henricks, M. et al. Arginine metabolism by macrophages promotes cardiac and muscle fibrosis in mdx muscular dystrophy. PLoS ONE 5, e10763 (2010). 24. Wehling-Henricks, M. et al. Macrophages escape Klotho gene silencing in the mdx mouse model of Duchenne muscular dystrophy and promote muscle growth and increase satellite cell numbers through a Klotho-mediated pathway. Hum. Mol. Genet. 27, 14–29 (2018). 52. White, J. D., Davies, M., McGeachie, J. & Grounds, M. D. An evaluation of leukaemia inhibitory factor as a potential therapeutic agent in the treatment of muscle disease. Neuromuscul. Disord. 12, 909–916 (2002). 53. Igarashi, A., Okochi, H., Bradham, D. M. & Grotendorst, G. R. Regulation of connective tissue growth factor gene expression in human skin fibroblasts and during wound repair. Mol. Biol. Cell 4, 637–645 (1993). 25. Adams, T. E. et al. Growth hormone preferentially induces the rapid, transient expression of SOCS-3, a novel inhibitor of cytokine receptor signaling. J. Biol. Chem. 273, 1285–1287 (1998). 54. Frazier, K., Williams, S., Kothapalli, D., Klapper, H. & Grotendorst, G. R. Stimulation of fibroblast cell growth, matrix production, and granulation tissue formation by connective tissue growth factor. J. Invest. Dermatol. 107, 404–411 (1996). 26. Villalta, S. A., Nguyen, H. X., Deng, B., Gotoh, T. & Tidball, J. G. Shifts in macrophage phenotypes and macrophage competition for arginine metabolism affect the severity of muscle pathology in muscular dystrophy. Hum. Mol. Genet. 18, 482–496 (2009). 55. Zanotti, S., Gibertini, S. & Mora, M. Altered production of extra-cellular matrix components by muscle-derived Duchenne muscular dystrophy fibroblasts before and after TGF-beta1 treatment. Cell Tissue Res. 339, 397–410 (2010). 27. Mojumdar, K. et al. Inflammatory monocytes promote progression of Duchenne muscular dystrophy and can be therapeutically targeted via CCR2. EMBO Mol. Med. 6, 1476–1492 (2014). 28. Curran, J. N., Winter, D. C. & Bouchier-Hayes, D. ARTICLE Biological fate and clinical implications of arginine metabolism in tissue healing. Wound Repair Regen. 14, 376–386 (2006). 56. Cencetti, F., Bernacchioni, C., Nincheri, P., Donati, C. & Bruni, P. Transforming growth factor-beta1 induces transdifferentiation of myoblasts into myofibroblasts via up-regulation of sphingosine kinase-1/S1P3 axis. Mol. Biol. Cell 21, 1111–1124 (2010). 29. Vidal, B. et al. Fibrinogen drives dystrophic muscle fibrosis via a TGFbeta/ alternative macrophage activation pathway. Genes Dev. 22, 1747–1752 (2008). 57. Morales, M. G. et al. Reducing CTGF/CCN2 slows down mdx muscle dystrophy and improves cell therapy. Hum. Mol. Genet. 22, 4938–4951 (2013). 30. Zhou, L. et al. Temporal and spatial mRNA expression patterns of TGF-beta1, 2, 3 and TbetaRI, II, III in skeletal muscles of mdx mice. Neuromuscul. Disord. 16, 32–38 (2006). 58. Gosselin, L. E. et al. Localization and early time course of TGF-beta 1 mRNA expression in dystrophic muscle. Muscle Nerve 30, 645–653 (2004). 31. Lemos, D. R. et al. Nilotinib reduces muscle fibrosis in chronic muscle injury by promoting TNF-mediated apoptosis of fibro/adipogenic progenitors. Nat. Med. 21, 786–794 (2015). 59. Cohn, R. D. et al. Angiotensin II type 1 receptor blockade attenuates TGF-β- induced failure of muscle regeneration in multiple myopathic states. Nat. Med. 13, 204–210 (2007). 32. Uezumi, A. et al. Fibrosis and adipogenesis originate from a common mesenchymal progenitor in skeletal muscle. J. Cell Sci. 124, 3654–3664 (2011). 60. Hoffman, E. P., Brown, R. H. & Kunkel, L. M. Dystrophin: the protein product of the Duchenne muscular dystrophy locus. Cell 51, 919–928 (1987). 33. Biressi, S., Miyabara, E. H., Gopinath, S. D., Carlig, P. M. M. & Rando, T. A. A Wnt-TGFβ2 axis induces a fibrogenic program in muscle stem cells from dystrophic mice. Sci. Transl. Med. 6, 267ra176 (2014). 61. Petrof, B. J., Shrager, J. B., Stedman, H. H., Kelly, A. M. & Sweeney, H. L. Dystrophin protects the sarcolemma from stresses developed during muscle contraction. Proc. Natl. Acad. Sci. USA 90, 3710–3714 (1993). 34. Peinado, H., Quintanilla, M. & Cano, A. Transforming growth factor beta-1 induces snail transcription factor in epithelial cell lines: mechanisms for epithelial mesenchymal transitions. J. Biol. Chem. 278, 21113–21123 (2003). 62. Laszlo, G. S. & Nathanson, N. M. Src family kinase-independent signal transduction and gene induction by leukemia inhibitory factor. J. Biol. Chem. 278, 27750–27757 (2003). 35. Liu, Y. et al. ARTICLE Transforming growth factor-β (TGF-β)-mediated connective tissue growth factor (CTGF) expression in hepatic stellate cells requires Stat3 signaling activation. J. Biol. Chem. 288, 30708–30719 (2013). 63. Qin, H. et al. SOCS3 deficiency promotes M1 macrophage polarization and inflammation. J. Immunol. 189, 3439–3448 (2012). 36. Ignotz, R. A. & Massagué, J. Transforming growth factor-beta stimulates the expression of fibronectin and collagen and their incorporation into the extracellular matrix. J. Biol. Chem. 261, 4337–4345 (1986). 64. Arnold, C. E. et al. A critical role for suppressor of cytokine signalling 3 in promoting M1 macrophage activation and function in vitro and in vivo. Immunology 141, 96–110 (2014). 65. Amalfitano, A. & Chamberlain, J. S. The mdx-amplification-resistant mutation system assay, a simple and rapid polymerase chain reaction-based detection of the mdx allele. Muscle Nerve 19, 1549–1553 (1996). 37. Lustig, B. et al. Negative feedback loop of Wnt signaling through upregulation of Conductin/Axin2 in colorectal and liver tumors. Mol. Cell. Biol. 22, 1184–1193 (2002). 38. Ishida, Y. & Nagata, K. Hsp47 as a collagen-specific molecular chaperone. Methods Enzymol. 499, 167–182 (2011). 66. Nolan, T., Hands, R. E. & Bustin, S. A. Quantification of mRNA using real- time RT-PCR. Nat. Protoc. 1, 1559–1582 (2006). 39. Taguchi, T., Nazneen, A., Al-Shihri, A. A., Turkistani, K. A. & Razzaque, M. S. Heat shock protein 47: a novel biomarker of phenotypically altered collagen- producing cells. Acta Histochem. Cytochem. 44, 35–41 (2011). 67. Bustin, S. A. et al. The MIQE guidelines: minimum information for publication of quantitative real-time PCR experiments. Clin. Chem. 55, 611–622 (2009). 40. Brack, A. S. et al. Increased Wnt signaling during aging alters muscle stem cell fate and increases fibrosis. Science 317, 807–810 (2007). 68. Wang, Y., Wehling-Henricks, M., Samengo, G. & Tidball, J. G. Increases of M2a macrophages and fibrosis in aging muscle are influenced by bone marrow aging and negatively regulated by muscle-derived nitric oxide. Aging Cell 14, 678–688 (2015). 41. Joe, A. W. B. et al. Muscle injury activates resident fibro/adipogenic progenitors that facilitate myogenesis. Nat. Cell Biol. 12, 153–163 (2010). 69. Burkholder, T. J., Fingado, B., Baron, S. & Lieber, R. L. Relationship between muscle fiber types and sizes and muscle architectural properties in the mouse hindlimb. J. Morphol. 221, 177–190 (1994). 42. Uezumi, A., Fukada, S., Yamamoto, N., Takeda, S. & Tsuchida, K. Mesenchymal progenitors distinct from satellite cells contribute to ectopic fat cell formation in skeletal muscle. Nat. Cell Biol. References Reduced necrosis of dystrophic muscle by depletion of host neutrophils, or blocking TNFalpha function with Etanercept in mdx mice. Neuromuscul. Disord. 16, 591–602 (2006). function with Etanercept in mdx mice. Neuromuscul. Disord. 16, 591–602 (2006). 12. Gorospe, J. R., Nishikawa, B. K. & Hoffman, E. P. Recruitment of mast cells to muscle after mild damage. J. Neurol. Sci. 135, 10–17 (1996). 12. Gorospe, J. R., Nishikawa, B. K. & Hoffman, E. P. Recruitment of mast cells to muscle after mild damage. J. Neurol. Sci. 135, 10–17 (1996). 13. Villalta, S. A., Deng, B., Rinaldi, C., Wehling-Henricks, M. & Tidball, J. G. IFN-γ promotes muscle damage in the mdx mouse model of Duchenne muscular dystrophy by suppressing M2 macrophage activation and inhibiting muscle cell proliferation. J. Immunol. 187, 5419–5428 (2011). 14. Villalta, S. A. et al. Interleukin-10 reduces the pathology of mdx muscular dystrophy by deactivating M1 macrophages and modulating macrophage phenotype. Hum. Mol. Genet. 20, 790–805 (2011). 15 TURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038/s41467-019-10614-1 | www.nature.com/naturecommunications Acknowledgements Hybridoma Bank, created by the NICHD of the NIH and maintained at The University of Iowa, Department of Biology, Iowa City, IA 52242, USA. ARTICLE 12, 143–152 (2010). 16 NATURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038/s41467-019-10614-1 | www.nature.com/naturecommunicatio ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-10614-1 Additional information 70. Bellardita, C. & Kiehn, O. Phenotypic characterization of speed-associated gait changes in mice reveals modular organization of locomotor networks. Curr. Biol. 25, 1426–1436 (2015). Supplementary Information accompanies this paper at https://doi.org/10.1038/s41467- 019-10614-1. Acknowledgements Reprints and permission information is available online at http://npg.nature.com/ reprintsandpermissions/ g Research reported in this publication was supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health under Award Numbers F32AR065845 (to S.S.W.), F31AR071783 (to I.F.), F32AR071233 (to J.R.), and RO1AR066036, RO1AR062579, and R21AR066817 (to J.G.T.). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Flow cytometry was performed in the UCLA Jonsson Com- prehensive Cancer Center (JCCC) and Center for AIDS Research Flow Cytometry Core Facility that is supported by National Institutes of Health awards P30 CA016042 and 5P30 AI028697, and by the JCCC, the UCLA AIDS Institute, the David Geffen School of Medicine at UCLA, the UCLA Chancellor’s Office, and the UCLA Vice Chancellor’s Office of Research. Confocal laser scanning microscopy was performed at the California NanoSystems Institute Advanced Light Microscopy/Spectroscopy Shared Resource Facility at UCLA. DNA microinjections for the production of the CD11b/LIF transgenic mice were performed at the University of California, Irvine Transgenic Mouse Facility. The Pax7 hybridoma developed by T.M. Jessell, Columbia University, was obtained from the Developmental Studies Hybridoma Bank, created by the NICHD of the NIH and maintained at The University of Iowa, Department of Biology, Iowa City, IA 52242, USA. Peer review information: Nature Communications thanks the anonymous reviewers for their contribution to the peer review of this work. Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/ licenses/by/4.0/. Author contributions S.S.W., M.W.-H., I.F., and J.G.T. conceived and designed the experiments. S.S.W., M.W.-H., I.F., C.B., J.R., and Y.W. performed the experiments. S.S.W., I.F., and J.G.T. analyzed the data and wrote the manuscript. © The Author(s) 2019 © The Author(s) 2019 17 NATURE COMMUNICATIONS | (2019) 10:2788 | https://doi.org/10.1038/s41467-019-10614-1 | www.nature.com/naturecommunications
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Human Occipital and Parietal GABA Selectively Influence Visual Perception of Orientation and Size
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Chen Song1,2,3, Kristian Sandberg1,4,5, Lau Møller Andersen4,6, Jakob Udby Blicher4 and Geraint Rees1,2 Chen Song1,2,3, Kristian Sandberg1,4,5, Lau Møller Andersen4,6, Jakob Udby Blicher4 and Geraint Rees1,2 1Institute of Cognitive Neuroscience, University College London, London WC1N 3AR, UK 2Wellcome Trust Centre for Neuroimaging, University College London, London WC1N 3BG, UK 3Department of Psychiatry, University of Wisconsin - Madison, Madison 53719 WI, USA 4Center of Functionally Integrative Neuroscience, Aarhus University, 8000 Aarhus C, Denmark 5Hammel Neurorehabilitation and Research Centre, Aarhus University Hospital, 8450 Hammel, Denmark 6NatMEG, Department of Clinical Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden Author contributions: C.S., K.S., and G.R. designed research; C.S., K.S., L.M.A., and J.B. performed research; C.S., K.S., L.M.A., and J.B. contributed unpublished reagents/analytic tools; C.S., K.S., L.M.A., and J.B. analyzed data; C.S., K.S., L.M.A., J.B., and G.R. wrote the paper. his Accepted Manuscript has not been copyedited and formatted. The final version may differ from this version. his Accepted Manuscript has not been copyedited and formatted. The final version may differ from this version. This Accepted Manuscript has not been copyedited and formatted. The final version may differ from this version. Research Articles: Behavioral/Cognitive DOI: 10.1523/JNEUROSCI.3945-16.2017 Department of Psychiatry, University of Wisconsin - Madison, Madison 11 12 4. Center of Functionally Integrative Neuroscience, Aarhus University, 80 13 14 5. Hammel Neurorehabilitation and Research Centre, Aarhus University H 15 16 6. NatMEG, Department of Clinical Neuroscience, Karolinska Institutet, 1 17 18 * These two authors contributed equally. 19 20 21 Correspondence: 22 23 Chen Song 24 Institute of Cognitive Neuroscience 25 University College London 26 London WC1N 3AR 27 UK 28 chen.song.09@ucl.ac.uk 29 30 OR 31 32 Kristian Sandberg 33 Center of Functionally Integrative Neuroscience 34 Aarhus University 35 8000 Aarhus C 36 Denmark 37 krissand@rm.dk 38 39 40 Abbreviated title: Selective influence of GABA on visual perception 41 42 43 Number of pages: 17 44 Number of figures: 5 45 Number of words for Abstract: 230 46 Number of words for Introduction: 529 47 Number of words for Discussion: 1003 48 49 50 Conflict of interest: None 51 52 53 Acknowledgements: We thank Dr. Jamie Near and Dr. Peter Jezzard at FM 54 providing the Magnetic Resonance Spectroscopy (MRS) sequence used in 55 supported by the Brain Research Trust (CS), the Danish Ministry of Scien 56 UNIK program (KS), and the Wellcome Trust (GR). 57 DOI: 10.1523/JNEUROSCI.3945-16.2017 Received: 23 December 2016 Revised: 27 April 2017 Accepted: 3 May 2017 Published: 21 August 2017 Author contributions: C.S., K.S., and G.R. designed research; C.S., K.S., L.M.A., and J.B. performed research; C.S., K.S., L.M.A., and J.B. contributed unpublished reagents/analytic tools; C.S., K.S., L.M.A., and J.B. analyzed data; C.S., K.S., L.M.A., J.B., and G.R. wrote the paper. Conflict of Interest: The authors declare no competing financial interests. We thank Dr. Jamie Near and Dr. Peter Jezzard at FMRIB, Oxford University, UK for providing the Magnetic Resonance Spectroscopy (MRS) sequence used in the current study. The study was supported by the Brain Research Trust (CS), the Danish Ministry of Science, Technology and Innovation's UNIK program (KS), and the Wellcome Trust (GR). We thank Dr. Jamie Near and Dr. Peter Jezzard at FMRIB, Oxford University, UK for providing the Magnetic Resonance Spectroscopy (MRS) sequence used in the current study. The study was supported by the Brain Research Trust (CS), the Danish Ministry of Science, Technology and Innovation's UNIK program (KS), and the Wellcome Trust (GR). Correspondence: Chen Song, Institute of Cognitive Neuroscience, University College London, London WC1N 3AR, UK, chen.song.09@ucl.ac.uk, OR Kristian Sandberg, Center of Functionally Integrative Neuroscience, Aarhus University, 8000 Aarhus C, Denmark, krissand@rm.dk Correspondence: Chen Song, Institute of Cognitive Neuroscience, University College London, London WC1N 3AR, UK, chen.song.09@ucl.ac.uk, OR Kristian Sandberg, Center of Functionally Integrative Neuroscience, Aarhus University, 8000 Aarhus C, Denmark, krissand@rm.dk Cite as: J. Neurosci ; 10.1523/JNEUROSCI.3945-16.2017 Cite as: J. Neurosci ; 10.1523/JNEUROSCI.3945-16.2017 Alerts: Sign up at www.jneurosci.org/cgi/alerts to receive customized email alerts when the fully formatted version of this article is published. Alerts: Sign up at www.jneurosci.org/cgi/alerts to receive customized email alerts when the fully formatted version of this article is published. Accepted manuscripts are peer-reviewed but have not been through the copyediting, formatting, or proofreading process. Copyright © 2017 Song et al. Copyright © 2017 Song et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license, which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed. Human occipital and parietal GABA selectivel 1 perception of orientation and size 2 3 4 Chen Song1,2,3,*, Kristian Sandberg1,4,5,*, Lau Møller Andersen4,6, Jakob Ud 5 6 1. Institute of Cognitive Neuroscience, University College London, Londo 7 8 2. Wellcome Trust Centre for Neuroimaging, University College London, 9 10 3. Human occipital and parietal GABA selectively influence visual 1 perception of orientation and size 2 3 perception of orientation and size 2 3 4 Chen Song1,2,3,*, Kristian Sandberg1,4,5,*, Lau Møller Andersen4,6, Jakob Udb 5 6 1. Institute of Cognitive Neuroscience, University College London, London 7 8 2. Wellcome Trust Centre for Neuroimaging, University College London, L 9 10 3. Department of Psychiatry, University of Wisconsin - Madison, Madison 11 12 4. Center of Functionally Integrative Neuroscience, Aarhus University, 800 13 14 5. Hammel Neurorehabilitation and Research Centre, Aarhus University Ho 15 16 6. NatMEG, Department of Clinical Neuroscience, Karolinska Institutet, 17 17 18 * These two authors contributed equally. 19 20 21 Correspondence: 22 23 Chen Song 24 Institute of Cognitive Neuroscience 25 University College London 26 London WC1N 3AR 27 UK 28 chen.song.09@ucl.ac.uk 29 30 OR 31 32 Kristian Sandberg 33 Center of Functionally Integrative Neuroscience 34 Aarhus University 35 8000 Aarhus C 36 Denmark 37 krissand@rm.dk 38 39 40 Abbreviated title: Selective influence of GABA on visual perception 41 42 43 Number of pages: 17 44 Number of figures: 5 45 Number of words for Abstract: 230 46 Number of words for Introduction: 529 47 Number of words for Discussion: 1003 48 49 50 Conflict of interest: None 51 52 53 Acknowledgements: We thank Dr. Jamie Near and Dr. Peter Jezzard at FMR 54 providing the Magnetic Resonance Spectroscopy (MRS) sequence used in t 55 supported by the Brain Research Trust (CS), the Danish Ministry of Science 56 UNIK program (KS), and the Wellcome Trust (GR). 57 Acknowledgements: We thank Dr. Jamie Near and Dr. Peter Jezzard at FMRIB, Oxford University, UK for 54 providing the Magnetic Resonance Spectroscopy (MRS) sequence used in the current study. The study was 55 supported by the Brain Research Trust (CS), the Danish Ministry of Science, Technology and Innovation's 56 UNIK program (KS), and the Wellcome Trust (GR). 57 1 ABSTRACT 58 Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in human brain. GABA level 59 varies substantially across individuals and this variability is associated with inter-individual differences in visual 60 perception. However, it remains unclear whether the association between GABA level and visual perception 61 reflects a general influence of visual inhibition, or whether GABA level of different cortical regions selectively 62 influences perception of different visual features. To address this, we studied how GABA level in parietal and 63 occipital cortices related to inter-individual differences in size, orientation, and brightness perception, in a group 64 of healthy young male participants. We used visual contextual illusion as a perceptual assay, since it dissociates 65 perceptual content from stimulus content and its magnitude reflects the effect of visual inhibition. Across 66 individuals, we observed selective correlations between GABA level and the magnitude of contextual illusion. 67 Specifically, parietal GABA level correlated with size illusion magnitude but not with orientation or brightness 68 illusion magnitude; in contrast, occipital GABA level correlated with orientation illusion magnitude but not with 69 size or brightness illusion magnitude. Our findings reveal a region- and feature-dependent influence of GABA 70 level on human visual perception. Parietal and occipital cortices contain, respectively, topographic maps of size 71 and orientation preference in which neural responses to sizes or orientations are modualted by intra-regional 72 lateral connections. We propose that these lateral connections may underlie the selective influence of GABA 73 level on visual feature perception. 74 SIGNIFICANCE STATEMENT 75 Gamma-aminobutyric acid (GABA), the primary inhibitory neurotransmitter in human visual system, varies 76 substantially across individuals and this variability is linked to inter-individual differences in many aspects of 77 visual perception. The widespread influence of GABA raises the question of whether inter-individual variability 78 in GABA reflects an overall variability in visual inhibition and has a general influence on visual perception, or 79 whether GABA level of different cortical regions has selective influence on perception of different visual 80 features. Here we report a region- and feature-dependent influence of GABA level on human visual perception. 81 Our findings suggest that GABA level of a cortical region selectively influences perception of visual features 82 that are topographically mapped in this region through intra-regional lateral connections. 83 Gamma-aminobutyric acid (GABA), the primary inhibitory neurotransmitter in human visual system, varies 76 substantially across individuals and this variability is linked to inter-individual differences in many aspects of 77 visual perception. The widespread influence of GABA raises the question of whether inter-individual variability 78 in GABA reflects an overall variability in visual inhibition and has a general influence on visual perception, or 79 whether GABA level of different cortical regions has selective influence on perception of different visual 80 features. Here we report a region- and feature-dependent influence of GABA level on human visual perception. 81 Our findings suggest that GABA level of a cortical region selectively influences perception of visual features 82 that are topographically mapped in this region through intra-regional lateral connections. 83 2 The inhibitory neurotransmitter Gamma-aminobutyric acid (GABA) plays a central role in visual processing 85 ranging from neural selectivity and neural response gain control, to synaptic plasticity and network oscillation 86 (Katzner et al., 2011; Lehmann et al., 2012; Priebe et al., 2008). GABA level (measured using Magnetic 87 Resonance Spectroscopy) varies substantially across human individuals and this variability may contribute to 88 inter-individual differences in visual processing and visual perception. Indeed, a higher GABA level is 89 associated with higher visual discrimination ability, lower susceptibility to distraction, stronger surround 90 suppression and stronger interocular suppression (Edden et al., 2009; Lunghi et al., 2015; Sandberg et al., 2014; 91 Sandberg et al., 2016; Vanloon et al., 2013; Yoon et al., 2010). This wide range of observations raises the question of whether inter-individual variability in GABA reflects an 95 overall variability in visual inhibition and has a general influence on visual perception, or whether GABA level 96 of different cortical regions has selective influence on perception of different visual features. One hypothesis is 97 that, GABA level of each cortical region is uniquely determined in each individual, possibly by a combination 98 of genetic and environmental factors (Bachtiar et al., 2015; Lunghi et al., 2015; Marenco et al., 2010; Taniguchi 99 et al., 2011). As such, GABA level of different cortical regions may exhibit dissociable inter-individual 100 variability and influence perception of different visual features separately. An alternative hypothesis is that, 101 GABA level of different cortical regions may co-vary as a result of common embryonic origins or shared 102 subcortical GABAergic projections (Caputi et al., 2013; Chen et al., 2015; Dammerman et al., 2000; Jinno et al., 103 2007; Picardo et al., 2011), and may influence perception of different visual features concurrently. 104 This wide range of observations raises the question of whether inter-individual variability in GABA reflects an 95 overall variability in visual inhibition and has a general influence on visual perception, or whether GABA level 96 of different cortical regions has selective influence on perception of different visual features. One hypothesis is 97 that, GABA level of each cortical region is uniquely determined in each individual, possibly by a combination 98 of genetic and environmental factors (Bachtiar et al., 2015; Lunghi et al., 2015; Marenco et al., 2010; Taniguchi 99 et al., 2011). As such, GABA level of different cortical regions may exhibit dissociable inter-individual 100 variability and influence perception of different visual features separately. An alternative hypothesis is that, 101 GABA level of different cortical regions may co-vary as a result of common embryonic origins or shared 102 subcortical GABAergic projections (Caputi et al., 2013; Chen et al., 2015; Dammerman et al., 2000; Jinno et al., 103 2007; Picardo et al., 2011), and may influence perception of different visual features concurrently. 104 To test these two alternative hypotheses, we studied how GABA level of parietal and occipital cortices related to 105 inter-individual differences in size, orientation, and brightness perception. SIGNIFICANCE STATEMENT 75 Moreover, in neurological disorders such as 92 attention-deficit / hyperactivity disorder and schizophrenia, both an abnormal level of GABA and an abnormal 93 performance in perceptual tasks are observed (Edden et al., 2012; Moult, 2009; Yoon et al., 2010). 94 Participants 120 Thirty-seven healthy volunteers (aged 20 to 40, all males, females ineligible due to menstrual cycle) gave 121 written informed consent to participate in this study that was approved by the local ethics committee, De 122 Videnskabsetiske Komitéer for Region Midtjylland, Denmark. All participants had normal or corrected-to- 123 normal vision, and no neurological or psychiatric history. The Magnetic Resonance Spectroscopy data of four 124 participants were contaminated by signal from lipids and the psychophysics data of three participants were 125 outliers of the normal distribution (Shapiro-Wilk test). These data were therefore excluded from further analysis. 126 Magnetic resonance spectroscopy measure of GABA 127 Neuroimaging took place in a Siemens Trio 3T MRI scanner. Structural MRI data were acquired using a T1- 128 weighted MPRAGE sequence (TR: 2420 msec; TE: 3.7 msec; resolution: 1 mm isotropic; scanning time: 5.5 129 min) and were used to guide the voxel placement in Magnetic Resonance Spectroscopy (MRS). Resting GABA 130 measures were acquired from a 2 cm isotropic voxel in the parietal lobe (TR: 2500 msec; TE: 68 msec; 240 edit 131 on and edit off averages; scan time: 20 min) and a 3 cm isotropic voxel in the occipital lobe (TR: 2500 msec; TE: 132 68 msec; 96 edit on and edit off averages; scan time: 8 min), using MEGA-PRESS method (Edden et al., 2007; 133 Mescher et al., 1998). To compensate for the size differences between the two voxels, the parietal voxel had a 134 longer scan time (20 min) than the occipital voxel (8 min). An even longer scan time (40 min) could lead to a 135 better compensation, however the subject motion would be a drawback. 136 Neuroimaging took place in a Siemens Trio 3T MRI scanner. Structural MRI data were acquired using a T1- 128 weighted MPRAGE sequence (TR: 2420 msec; TE: 3.7 msec; resolution: 1 mm isotropic; scanning time: 5.5 129 min) and were used to guide the voxel placement in Magnetic Resonance Spectroscopy (MRS). Resting GABA 130 measures were acquired from a 2 cm isotropic voxel in the parietal lobe (TR: 2500 msec; TE: 68 msec; 240 edit 131 on and edit off averages; scan time: 20 min) and a 3 cm isotropic voxel in the occipital lobe (TR: 2500 msec; TE: 132 68 msec; 96 edit on and edit off averages; scan time: 8 min), using MEGA-PRESS method (Edden et al., 2007; 133 Mescher et al., 1998). To compensate for the size differences between the two voxels, the parietal voxel had a 134 longer scan time (20 min) than the occipital voxel (8 min). An even longer scan time (40 min) could lead to a 135 better compensation, however the subject motion would be a drawback. 136 We used a standard resting state protocol where participants had their eyes open and faced the insider of the 137 scanner with no mirrors attached or no visual stimuli presented (Edden et al., 2009; Ogorman et al., 2011). Occipital cortex contains a map of 106 orientation preference in which individual neurons respond preferentially to specific orientation and neighboring 107 neurons to adjacent orientations; by contrast, parietal cortex contains a map of size preference in which 108 individual neuronal populations respond preferentially to specific size of a visually presented object and 109 neighboring neurons to adjacent sizes (Harvey et al., 2015; Yacoub et al., 2007). Since neurotransmitters are 110 contained in and released at synapses, GABA level of a cortical region may influence visual feature perception 111 through lateral connections within the region. These lateral connections link neighboring neurons with similar 112 feature preferences, and underlie contextual illusions where the perceived feature (e.g., orientation, size) of a 113 3 visual stimulus is modulated by the stimulus surrounding it (Bosten et al., 2010; Cannon et al., 1996; Kapadia et 114 al., 1999; Stettler et al., 2002; Song et al., 2013). We therefore used contextual illusion as a perceptual assay, 115 hypothesizing that selective correlation may be observed between GABA level of a cortical region and 116 contextual illusion for visual features topographically mapped in this region. Specifically, parietal and occipital 117 GABA level may correlate selectively with the magnitude of size and orientation illusion. 118 visual stimulus is modulated by the stimulus surrounding it (Bosten et al., 2010; Cannon et al., 1996; Kapadia et 114 al., 1999; Stettler et al., 2002; Song et al., 2013). We therefore used contextual illusion as a perceptual assay, 115 hypothesizing that selective correlation may be observed between GABA level of a cortical region and 116 contextual illusion for visual features topographically mapped in this region. Specifically, parietal and occipital 117 GABA level may correlate selectively with the magnitude of size and orientation illusion. 118 A theoretical model has been proposed to subtract MM 152 contribution post-hoc (Murdoch et al, 2011). Nevertheless, this technique could introduce additional variability 153 into the estimated GABA values, and is thus rarely used (see discussion in Mullins et al., 2014). Newer 154 sequences such as MEGA-SPECIAL (Near et al., 2011) and SPECIAL (Near et al., 2013) aims to remove MM 155 contribution by editing and modelling, respectively. However, both sequences have other drawbacks such as the 156 imperfect lipid suppression. The raw GABA value is subject to bias from day-to-day scanner-related variation. 157 For an unbiased estimate of GABA, a normalization of raw GABA value to Cr is typically applied (Mullins et 158 al., 2012), since Cr resonates around the same frequency (3 ppm) as GABA and is not affected by disturbances 159 that depend on the resonance frequency. The ratio GABA+/Cr was calculated to quantify GABA level. 160 The analysis of MRS data was performed by author JUB who was blind to the psychophysics data, and 161 constituted part of a database that have been reported in previous studies (Near et al., 2014; Sandberg et al., 162 2014; Sandberg et al., 2016). The MRS data were first preprocessed in MATLAB with FID-A software for 163 motion corruption removal, drift correction and phasing, and then analyzed in jMRUI software with AMARES 164 package (Edden et al., 2007; Mescher et al., 1998; Simpson et al., 2015). Data were visually inspected for noise, 165 line broadening, voxel misplacement and lipid contamination. Four participants who had spectra with large lipid 166 contamination failed to pass the visual inspection and were excluded from further analysis. The quality of the 167 included spectra was evaluated by calculating signal-to-noise ratio (SNR), line width and fit uncertainty. 168 The analysis of MRS data was performed by author JUB who was blind to the psychophysics data, and 161 constituted part of a database that have been reported in previous studies (Near et al., 2014; Sandberg et al., 162 2014; Sandberg et al., 2016). The MRS data were first preprocessed in MATLAB with FID-A software for 163 motion corruption removal, drift correction and phasing, and then analyzed in jMRUI software with AMARES 164 package (Edden et al., 2007; Mescher et al., 1998; Simpson et al., 2015). Data were visually inspected for noise, 165 line broadening, voxel misplacement and lipid contamination. The MEGA-PRESS method measures GABA concentrations through the acquisition of two spectra: one with an 146 editing pulse targeting the C3-GABA peak at 1.9 ppm (edit on), and one with an editing pulse targeting the 147 water peak on the symmetrical side at 7.5 ppm (edit off). By averaging the two spectra, the Creatine (Cr) peak at 148 3.0 ppm was quantified. By subtracting the two spectra, the C4-GABA peak at 3 ppm was quantified. This C4- 149 GABA peak is often referred to as GABA+, since a coupled macromolecule (MM) resonance at 3 ppm is co- 150 edited and contributes to the measured signal. Due to the limitation of the MEGA-PRESS sequence, the exact 151 MM contribution is difficult to estimate or remove. A theoretical model has been proposed to subtract MM 152 contribution post-hoc (Murdoch et al, 2011). Nevertheless, this technique could introduce additional variability 153 into the estimated GABA values, and is thus rarely used (see discussion in Mullins et al., 2014). Newer 154 sequences such as MEGA-SPECIAL (Near et al., 2011) and SPECIAL (Near et al., 2013) aims to remove MM 155 contribution by editing and modelling, respectively. However, both sequences have other drawbacks such as the 156 imperfect lipid suppression. The raw GABA value is subject to bias from day-to-day scanner-related variation. 157 For an unbiased estimate of GABA, a normalization of raw GABA value to Cr is typically applied (Mullins et 158 al., 2012), since Cr resonates around the same frequency (3 ppm) as GABA and is not affected by disturbances 159 that depend on the resonance frequency. The ratio GABA+/Cr was calculated to quantify GABA level. 160 The MEGA-PRESS method measures GABA concentrations through the acquisition of two spectra: one with an 146 editing pulse targeting the C3-GABA peak at 1.9 ppm (edit on), and one with an editing pulse targeting the 147 water peak on the symmetrical side at 7.5 ppm (edit off). By averaging the two spectra, the Creatine (Cr) peak at 148 3.0 ppm was quantified. By subtracting the two spectra, the C4-GABA peak at 3 ppm was quantified. This C4- 149 GABA peak is often referred to as GABA+, since a coupled macromolecule (MM) resonance at 3 ppm is co- 150 edited and contributes to the measured signal. Due to the limitation of the MEGA-PRESS sequence, the exact 151 MM contribution is difficult to estimate or remove. Magnetic resonance spectroscopy measure of GABA 127 MRS 138 measure of resting GABA varies little across day or even months (Evans et al., 2010; Near et al., 2014). The 139 We used a standard resting state protocol where participants had their eyes open and faced the insider of the 137 scanner with no mirrors attached or no visual stimuli presented (Edden et al., 2009; Ogorman et al., 2011). MRS 138 measure of resting GABA varies little across day or even months (Evans et al., 2010; Near et al., 2014). The 139 We used a standard resting state protocol where participants had their eyes open and faced the insider of the 137 scanner with no mirrors attached or no visual stimuli presented (Edden et al., 2009; Ogorman et al., 2011). MRS 138 measure of resting GABA varies little across day or even months (Evans et al., 2010; Near et al., 2014). The 139 4 high test-retest reliability suggests that the scanning order will not bias the measures. Nevertheless, to minimize 140 the between-subject variance of no interest, we kept the scanning order identical for all participants, collecting 141 data for the occipital voxel first and the parietal voxel second. The parietal voxel was placed on the anterior part 142 of the superior parietal lobe with its anterior border in parallel to the postcentral gyrus. The occipital voxel was 143 placed to cover the calcarine sulcus bilaterally with its anterior border in alignment with the parietal-occipital 144 sulcus. Care was taken to avoid the inclusion of the scalp and/or the tentorium cerebelli in the voxels. 145 Psychophysics measure of contextual illusion 178 The size illusion stimulus comprised two white circles 182 (1° diameter), a reference one surrounded by sixteen small white circles (0.2° diameter) and a test one by seven 183 large white circles (2° diameter), presented simultaneously for 500 msec on two sides of the fixation (3.85° 184 eccentricity) with randomized spatial order. The orientation illusion stimulus comprised two circular gratings 185 (45° orientation, 1.5° diameter, 2.5 cycles/° spatial frequency, 100% contrast), a reference one surrounded by an 186 annular grating (60° orientation, 4.5° diameter, 2.5 cycles/° spatial frequency, 100% contrast) and a test one 187 with no surround. The brightness illusion stimulus comprised two gray circles (50% luminance, 1.5° diameter), 188 a reference one surrounded by white annulus (4.5° diameter) and a test one by black annulus (4.5° diameter). 189 Psychophysics took place in a dark room. Visual stimuli were presented on a 17-inch LCD monitor (spatial 179 resolution: 1024 x 768 pixels; temporal resolution: 60 Hz) and viewed through a chin rest. The magnitudes of 180 size illusion (Ebbinghaus illusion), orientation illusion (tilt illusion), and brightness illusion (simultaneous 181 contrast illusion) were measured in separate experiments. The size illusion stimulus comprised two white circles 182 (1° diameter), a reference one surrounded by sixteen small white circles (0.2° diameter) and a test one by seven 183 large white circles (2° diameter), presented simultaneously for 500 msec on two sides of the fixation (3.85° 184 eccentricity) with randomized spatial order. The orientation illusion stimulus comprised two circular gratings 185 (45° orientation, 1.5° diameter, 2.5 cycles/° spatial frequency, 100% contrast), a reference one surrounded by an 186 annular grating (60° orientation, 4.5° diameter, 2.5 cycles/° spatial frequency, 100% contrast) and a test one 187 with no surround. The brightness illusion stimulus comprised two gray circles (50% luminance, 1.5° diameter), 188 a reference one surrounded by white annulus (4.5° diameter) and a test one by black annulus (4.5° diameter). 189 To minimize the confounding factors such as decision factors (Gold et al., 2012; Vogels et al., 1986), we kept 190 the psychophysical procedures identical for all three illusions. Psychophysics measure of contextual illusion 178 Psychophysics took place in a dark room. Visual stimuli were presented on a 17-inch LCD monitor (spatial 179 resolution: 1024 x 768 pixels; temporal resolution: 60 Hz) and viewed through a chin rest. The magnitudes of 180 size illusion (Ebbinghaus illusion), orientation illusion (tilt illusion), and brightness illusion (simultaneous 181 contrast illusion) were measured in separate experiments. The size illusion stimulus comprised two white circles 182 (1° diameter), a reference one surrounded by sixteen small white circles (0.2° diameter) and a test one by seven 183 large white circles (2° diameter), presented simultaneously for 500 msec on two sides of the fixation (3.85° 184 eccentricity) with randomized spatial order. The orientation illusion stimulus comprised two circular gratings 185 (45° orientation, 1.5° diameter, 2.5 cycles/° spatial frequency, 100% contrast), a reference one surrounded by an 186 annular grating (60° orientation, 4.5° diameter, 2.5 cycles/° spatial frequency, 100% contrast) and a test one 187 with no surround. The brightness illusion stimulus comprised two gray circles (50% luminance, 1.5° diameter), 188 a reference one surrounded by white annulus (4.5° diameter) and a test one by black annulus (4.5° diameter). 189 To minimize the confounding factors such as decision factors (Gold et al., 2012; Vogels et al., 1986), we kept 190 the psychophysical procedures identical for all three illusions. Participants first performed a match-to-standard 191 session in which they manually adjusted the size, orientation, or luminance of the test stimulus till it matched 192 the perceived size, orientation, or luminance of the reference stimulus, and a visual discrimination session in 193 which the size, orientation, and luminance discrimination threshold was measured through a standard 2-up-1- 194 down staircase. The point of subjective equality measured from the match-to-standard session and the visual 195 discrimination threshold measured from the staircase session were used to guide the choices of stimulus 196 Psychophysics took place in a dark room. Visual stimuli were presented on a 17-inch LCD monitor (spatial 179 resolution: 1024 x 768 pixels; temporal resolution: 60 Hz) and viewed through a chin rest. The magnitudes of 180 size illusion (Ebbinghaus illusion), orientation illusion (tilt illusion), and brightness illusion (simultaneous 181 contrast illusion) were measured in separate experiments. Four participants who had spectra with large lipid 166 contamination failed to pass the visual inspection and were excluded from further analysis. The quality of the 167 included spectra was evaluated by calculating signal-to-noise ratio (SNR), line width and fit uncertainty. 168 5 Examples of typical spectra are shown in Fig. 1. SNR was calculated using the difference spectrum following 169 the phase adjustment such that the N-acetylaspartate (NAA) peak was upright with a phase of 0 degree. Signal 170 was calculated as the maximal intensity of the NAA peak in the difference spectrum; noise was calculated as the 171 standard deviation of the noise in the signal-free spectrum, following a baseline correction to remove any 1st 172 and 2nd order baseline variations. SNR was 108 for the parietal voxel and 226 for the occipital voxel. Line 173 width was calculated by measuring the full width at half maximum of the NAA peak in the difference spectrum. 174 Mean line width was 4.8 Hz for the parietal voxel and 5.4 Hz for the occipital voxel. Fit uncertainty was 175 measured as the SD/amplitude ratio output by jMRUI. Mean SD/amplitude ratio was 0.04 for the parietal voxel 176 and 0.03 for the occipital voxel. 177 The data from the two-alternative-forced choice session were fitted with psychometric function to measure the 202 50% threshold point where the two central stimuli appeared perceptually equal despite their physical difference. 203 The goodness-of-fitting (R-square) was 0.963 ± 0.033 for orientation illusion, 0.956 ± 0.041 for size illusion, 204 and 0.960 ± 0.033 for brightness illusion. It did not differ significantly between illusions (size illusion versus 205 orientation illusion: T(29) = 1.03, p = 0.313; size illusion versus brightness illusion: T(29) = 0.47, p = 0.640; 206 orientation illusion versus brightness illusion: T(29) = 0.28, p = 0.785), or correlate significantly with GABA 207 (size illusion and parietal GABA: r = -0.194, p = 0.304; size illusion and occipital GABA: r = 0.143, p = 0.451; 208 orientation illusion and parietal GABA: r = 0.244, p = 0.194; orientation illusion and occipital GABA: r = 0.142, 209 p = 0.456; brightness illusion and parietal GABA: r = -0.224, p = 0.234; brightness illusion and occipital GABA: 210 r = 0.174, p = 0.359). The physical difference between the two central stimuli at the 50% threshold point was 211 calculated to quantify the illusion magnitude. 212 The data from the two-alternative-forced choice session were fitted with psychometric function to measure the 202 50% threshold point where the two central stimuli appeared perceptually equal despite their physical difference. 203 The goodness-of-fitting (R-square) was 0.963 ± 0.033 for orientation illusion, 0.956 ± 0.041 for size illusion, 204 and 0.960 ± 0.033 for brightness illusion. It did not differ significantly between illusions (size illusion versus 205 orientation illusion: T(29) = 1.03, p = 0.313; size illusion versus brightness illusion: T(29) = 0.47, p = 0.640; 206 orientation illusion versus brightness illusion: T(29) = 0.28, p = 0.785), or correlate significantly with GABA 207 (size illusion and parietal GABA: r = -0.194, p = 0.304; size illusion and occipital GABA: r = 0.143, p = 0.451; 208 orientation illusion and parietal GABA: r = 0.244, p = 0.194; orientation illusion and occipital GABA: r = 0.142, 209 p = 0.456; brightness illusion and parietal GABA: r = -0.224, p = 0.234; brightness illusion and occipital GABA: 210 r = 0.174, p = 0.359). The physical difference between the two central stimuli at the 50% threshold point was 211 calculated to quantify the illusion magnitude. Psychophysics measure of contextual illusion 178 Participants first performed a match-to-standard 191 session in which they manually adjusted the size, orientation, or luminance of the test stimulus till it matched 192 the perceived size, orientation, or luminance of the reference stimulus, and a visual discrimination session in 193 which the size, orientation, and luminance discrimination threshold was measured through a standard 2-up-1- 194 down staircase. The point of subjective equality measured from the match-to-standard session and the visual 195 discrimination threshold measured from the staircase session were used to guide the choices of stimulus 196 6 parameters in the subsequent two-alternative-forced choice session. There, participants were asked on 112 trials 197 to judge which central stimulus was larger (for size illusion), more tilted (for orientation illusion), or brighter 198 (for brightness illusion). The size, orientation, or luminance of the reference stimulus was kept constant; that of 199 the test stimulus was varied between seven values (16 trials per value) around the point of subjective equality 200 acquired from match-to-standard session, with a step size equal to visual discrimination threshold. 201 212 7 To account for the influence of Weber’s law (Shen, 2013), we used the log transform of the illusion magnitude 213 and the semi-log plots (Fig. 3~5) to assess inter-individual differences. Since the magnitude of orientation 214 illusion is subject to oblique effect (Clifford, 2014), we performed additional control experiments in a group of 215 twenty healthy volunteers (aged 21 to 35, 11 females) to test the influence of stimulus orientation (cardinal 216 versus oblique) on the measure of inter-individual differences. We found that although the illusion magnitude 217 was weaker for cardinal condition than oblique condition (t(19) = 20.362, p < 10-13), the illusion magnitude were 218 highly correlated between the two conditions (r = 0.866, p < 10-6). This observation suggested that inter- 219 individual differences in orientation illusion magnitude were not biased by oblique effect. 220 Statistics 221 Pearson’s correlation can capture the linearity in the relation between two variables, whereas Spearman’s rank 222 correlation can only reflect whether two variables are monotonically related or not. For example, Spearman’s 223 To account for the influence of Weber’s law (Shen, 2013), we used the log transform of the illusion magnitude 213 and the semi-log plots (Fig. 3~5) to assess inter-individual differences. Since the magnitude of orientation 214 illusion is subject to oblique effect (Clifford, 2014), we performed additional control experiments in a group of 215 twenty healthy volunteers (aged 21 to 35, 11 females) to test the influence of stimulus orientation (cardinal 216 versus oblique) on the measure of inter-individual differences. We found that although the illusion magnitude 217 was weaker for cardinal condition than oblique condition (t(19) = 20.362, p < 10-13), the illusion magnitude were 218 highly correlated between the two conditions (r = 0.866, p < 10-6). This observation suggested that inter- 219 Pearson’s correlation can capture the linearity in the relation between two variables, whereas Spearman’s rank 222 correlation can only reflect whether two variables are monotonically related or not. For example, Spearman’s 223 Pearson’s correlation can capture the linearity in the relation between two variables, whereas Spearman’s rank 222 correlation can only reflect whether two variables are monotonically related or not. RESULTS 234 We found that GABA level in parietal cortex (0.252 ± 0.035) and GABA level in occipital cortex (0.299 ± 0.042) 235 exhibited dissociable inter-individual variability (Fig. 2; r = -0.066, 95% C.I. of r = [-0.372, 0.250], p = 0.730, N 236 = 30). Subsequently, we studied how parietal GABA level versus occipital GABA level contributed to inter- 237 individual differences in size illusion (Ebbinghaus illusion), orientation illusion (tilt illusion), and brightness 238 illusion (simultaneous contrast illusion). 239 We found that GABA level in parietal cortex (0.252 ± 0.035) and GABA level in occipital cortex (0.299 ± 0.042) 235 exhibited dissociable inter-individual variability (Fig. 2; r = -0.066, 95% C.I. of r = [-0.372, 0.250], p = 0.730, N 236 = 30). Subsequently, we studied how parietal GABA level versus occipital GABA level contributed to inter- 237 individual differences in size illusion (Ebbinghaus illusion), orientation illusion (tilt illusion), and brightness 238 illusion (simultaneous contrast illusion). 239 Across individuals, we observed a positive correlation between the magnitude of size illusion and parietal 240 GABA level (Fig. 3; r = 0.395, 95% C.I. of r = [0.117, 0.610], p = 0.031, N = 30). By contrast, we did not 241 observe any significant correlation between the magnitude of size illusion and occipital GABA level (Fig. 3; r = 242 -0.038, 95% C.I. of r = [-0.317, 0.250], p = 0.841, N = 30). Moreover, compared to occipital GABA level, 243 parietal GABA level showed a significantly higher correlation with size illusion magnitude (t(27) = 2.369, p = 244 0.018). These results suggest a selective correlation between size illusion and parietal GABA. 245 Across individuals, we observed a positive correlation between the magnitude of size illusion and parietal 240 GABA level (Fig. 3; r = 0.395, 95% C.I. of r = [0.117, 0.610], p = 0.031, N = 30). By contrast, we did not 241 observe any significant correlation between the magnitude of size illusion and occipital GABA level (Fig. 3; r = 242 -0.038, 95% C.I. of r = [-0.317, 0.250], p = 0.841, N = 30). Moreover, compared to occipital GABA level, 243 parietal GABA level showed a significantly higher correlation with size illusion magnitude (t(27) = 2.369, p = 244 0.018). These results suggest a selective correlation between size illusion and parietal GABA. For example, Spearman’s 223 7 correlation coefficient will return the same result of 1 for two variables that both monotonically increase, 224 regardless of whether their rates of increase are linearly or non-linearly correlated; by contrast, Pearson’s 225 correlation coefficient can capture the difference between these two conditions. As such, Pearson’s correlation 226 coefficient is a more suitable test for studying the difference in correlation coefficient between conditions (e.g., 227 between size illusion and parietal versus occipital GABA). Application of Pearson’s correlation requires the 228 data to satisfy normal distribution. Shapiro-Wilk test failed to refute the assumption of normality for parietal 229 GABA level (W = 0.952, p = 0.187), occipital GABA level (W = 0.962, p = 0.295), size illusion magnitude (W 230 = 0.937, p = 0.072), orientation illusion magnitude (W = 0.985, p = 0.942), or brightness illusion magnitude (W 231 = 0.960, p = 0.314). Therefore, Pearson’s correlation was used throughout the study to test the relations between 232 variables, with age regressed out. 233 RESULTS 234 255 These results suggest that GABA level does not influence all types of contextual illusion, and its correlation 256 with size or orientation illusion may relate with the way how stimulus size or orientation is cortically processed. 257 For the brightness illusion, we did not observe any significant correlation across individuals between the illusion 251 magnitude and parietal GABA level (Fig. 5; r = -0.149, 95% C.I. of r = [-0.456, 0.163], p = 0.431, N = 30) or 252 occipital GABA level (Fig. 5; r = -0.017, 95% C.I. of r = [-0.377, 0.391], p = 0.927, N = 30). Accordingly, the 253 correlation between parietal GABA level and brightness illusion magnitude was not significantly different from 254 the correlation between occipital GABA level and brightness illusion magnitude (t(27) = 0.690, p = 0.490). 255 These results suggest that GABA level does not influence all types of contextual illusion, and its correlation 256 with size or orientation illusion may relate with the way how stimulus size or orientation is cortically processed. 257 RESULTS 234 245 Conversely, across individuals, the magnitude of orientation illusion exhibited a positive correlation with 246 occipital GABA level (Fig. 4; r = 0.367, 95% C.I. of r = [0.042, 0.599], p = 0.046, N = 30), but not with parietal 247 GABA level (Fig. 4; r = 0.002, 95% C.I. of r = [-0.363, 0.355], p = 0.990, N = 30). Moreover, occipital GABA 248 level correlated with orientation illusion magnitude significantly higher than parietal GABA level did (t(27) = 249 1.990, p = 0.047). These results suggest a selective correlation between orientation illusion and occipital GABA. 250 Conversely, across individuals, the magnitude of orientation illusion exhibited a positive correlation with 246 occipital GABA level (Fig. 4; r = 0.367, 95% C.I. of r = [0.042, 0.599], p = 0.046, N = 30), but not with parietal 247 GABA level (Fig. 4; r = 0.002, 95% C.I. of r = [-0.363, 0.355], p = 0.990, N = 30). Moreover, occipital GABA 248 level correlated with orientation illusion magnitude significantly higher than parietal GABA level did (t(27) = 249 1.990, p = 0.047). These results suggest a selective correlation between orientation illusion and occipital GABA. 250 Conversely, across individuals, the magnitude of orientation illusion exhibited a positive correlation with 246 occipital GABA level (Fig. 4; r = 0.367, 95% C.I. of r = [0.042, 0.599], p = 0.046, N = 30), but not with parietal 247 GABA level (Fig. 4; r = 0.002, 95% C.I. of r = [-0.363, 0.355], p = 0.990, N = 30). Moreover, occipital GABA 248 level correlated with orientation illusion magnitude significantly higher than parietal GABA level did (t(27) = 249 1.990, p = 0.047). These results suggest a selective correlation between orientation illusion and occipital GABA. 250 8 For the brightness illusion, we did not observe any significant correlation across individuals between the illusion 251 magnitude and parietal GABA level (Fig. 5; r = -0.149, 95% C.I. of r = [-0.456, 0.163], p = 0.431, N = 30) or 252 occipital GABA level (Fig. 5; r = -0.017, 95% C.I. of r = [-0.377, 0.391], p = 0.927, N = 30). Accordingly, the 253 correlation between parietal GABA level and brightness illusion magnitude was not significantly different from 254 the correlation between occipital GABA level and brightness illusion magnitude (t(27) = 0.690, p = 0.490). DISCUSSION 258 Taken together, our study reveals a region- and feature-dependent influence of neurotransmitter level on human 259 visual perception. We show that inter-individual variability in parietal GABA level correlated with size illusion 260 magnitude but not with orientation or brightness illusion magnitude; in contrast, inter-individual variability in 261 occipital GABA level correlated with orientation illusion magnitude but not with size or brightness illusion 262 magnitude. Our findings suggest that inter-individual variability in GABA does not reflect a general variability 263 in visual inhibition; instead, GABA level of different cortical regions has selective influence on perception of 264 different visual features. This influence is likely to be exerted through lateral connections within the cortical 265 region and is observed specifically for visual features mediated by such connections. 266 In occipital cortex, neurons exhibit orientation preference such that their response is the strongest for a preferred 267 orientation and gradually decays as the stimulus orientation deviates from this preferred orientation (Ringach et 268 al., 2002). Neurons preferring adjacent orientations are cortically adjacent to one another and are connected by 269 intra-regional lateral connections (Bock et al., 2011; Li et al., 2012; Yacoub et al., 2007). This topographical 270 organization of lateral connections allows the orientation preference of neurons to be modulated by the activity 271 of their adjacent neurons, and the level of occipital GABA to affect the degree of modulation (Burr et al., 1981; 272 Chavane et al., 2011; Eysel et al., 1990; Fitzpatrick, 2000; Gilbert et al., 1996; Morrone et al., 1987; Smith et al., 273 2006; Stettler et al., 2002). This neural-level modulation may then give rise to perceptual-level modulation, 274 where the perceived orientation of a stimulus is modulated by the orientation of the stimulus surrounding it 275 (Schwartz et al., 2007; Song et al., 2013). If so, the correlation between orientation illusion magnitude and 276 occipital GABA level could be a perceptual reflection of the link between neural-level modulation and GABA. 277 9 9 Whereas orientation preference is topographically mapped in occipital cortex with neurons preferring more 278 similar orientations being more highly connected, there is no topographic map of size preference in occipital 279 cortex (Chklovskii et al., 2004; Swindale, 2000). As such, a local GABA influence, exerted through lateral 280 connections within occipital cortex, is likely to be specific to orientation illusion and not generalizable to size 281 illusion. DISCUSSION 258 Just as the topographic map of orientation preference is prominent in occipital cortex (Kaschube et al., 282 2010; Wolf et al., 1998; Yacoub et al., 2007), a topographic map of size preference exists in parietal cortex 283 where individual neuronal populations respond preferentially to specific size and adjacent neurons to adjacent 284 sizes (Harvey et al., 2015). By contrast, there is no map of orientation preference in parietal cortex. Therefore, a 285 local GABA influence, exerted through lateral connections within parietal cortex, would be specific to size 286 illusion and not generalizable to orientation illusion. Similar to the topogrpahical maps of orientation preference 287 and size preference in visual cortices, neurons in the retina exhibit preference for stimulus luminance and are 288 topographically connected by their luminance preference. Possibly, the inter-individual differences in brightness 289 illusions may associate with inter-individual variability in retinal GABA (Lukasiewicz et al., 1998; Wu, 2010). 290 Moreover, since neural responses to visual features are modulated not only by intra-regional lateral connections 291 but also by inter-regional feedback connections (Fitzpatrick, 2000; Smith et al., 2006), the lack of correlation 292 between brightness illusion and occipital or parietal GABA could also indicate a predominant contribution of 293 inter-regional (as opposed to intra-regional) modulation to this illusion (Kinoshita, 2001; Perna et al., 2005). 294 Whereas orientation preference is topographically mapped in occipital cortex with neurons preferring more 278 similar orientations being more highly connected, there is no topographic map of size preference in occipital 279 cortex (Chklovskii et al., 2004; Swindale, 2000). As such, a local GABA influence, exerted through lateral 280 connections within occipital cortex, is likely to be specific to orientation illusion and not generalizable to size 281 illusion. Just as the topographic map of orientation preference is prominent in occipital cortex (Kaschube et al., 282 2010; Wolf et al., 1998; Yacoub et al., 2007), a topographic map of size preference exists in parietal cortex 283 where individual neuronal populations respond preferentially to specific size and adjacent neurons to adjacent 284 sizes (Harvey et al., 2015). By contrast, there is no map of orientation preference in parietal cortex. Therefore, a 285 local GABA influence, exerted through lateral connections within parietal cortex, would be specific to size 286 illusion and not generalizable to orientation illusion. DISCUSSION 258 Similar to the topogrpahical maps of orientation preference 287 and size preference in visual cortices, neurons in the retina exhibit preference for stimulus luminance and are 288 topographically connected by their luminance preference. Possibly, the inter-individual differences in brightness 289 illusions may associate with inter-individual variability in retinal GABA (Lukasiewicz et al., 1998; Wu, 2010). 290 Moreover, since neural responses to visual features are modulated not only by intra-regional lateral connections 291 but also by inter-regional feedback connections (Fitzpatrick, 2000; Smith et al., 2006), the lack of correlation 292 between brightness illusion and occipital or parietal GABA could also indicate a predominant contribution of 293 inter-regional (as opposed to intra-regional) modulation to this illusion (Kinoshita, 2001; Perna et al., 2005). 294 This account, that GABA level of a cortical region influences perception of visual features topographically 295 mapped in this region, would be able to explain the reported correlations between occipital GABA level and 296 orientation discrimination threshold (Edden et al., 2009). The intra-regional modulation exerted through lateral 297 connections may not only shift the orientation preference of neurons, and give rise perceptual shifts in 298 orientation illusion, but also sharpen the orientation tuning of neurons, and give rise perceptual sharpenings in 299 orientation discrimination (Benyishiai et al., 1995; Orban et al., 1998; Somers et al., 1995; Song et al., 2013; 300 Song et al., 2015). As such, the influence of occipital GABA level on orientation illusion could be mirrored in 301 orientation discrimination (Song et al., 2013). In addition to orientation preference, ocular preference is also 302 topographically mapped in occipital cortex, where individual neurons respond preferentially to stimulus from a 303 specific eye, and adjacent neurons to opposite eyes (Adams et al., 2007; Dechent et al., 2000; Menon et al., 304 1997). There, lateral connections would link neurons with opposite ocular preference, allowing the influence of 305 occipital GABA on orientation perception to generalize to binocular perception. This would explain the reported 306 decrease in both occipital GABA and interocular suppression after monocular deprivation (Lunghi et al., 2015). 307 10 This account, that GABA level of a cortical region influences perception of visual features topographically 308 mapped in this region, further predicts a correlation between parietal GABA level and numerosity perception. 309 Just as occipital cortex is crucial for processing low-level visual features and contains maps of orientation 310 preference and ocular preference, parietal cortex is important for processing high-level visual features and 311 contains maps of size preference and numerosity preference (Bueti et al., 2009; Chklovskii et al., 2004; Dehaene 312 et al., 2007; Dormal et al., 2008; Harvey et al., 2013; Harvey et al., 2015; Kadosh et al., 2009; Nieder et al., 313 2009; Pinel et al., 2004; Roitman et al., 2007; Roitman et al., 2012; Walsh, 2003). The lateral connections in 314 parietal cortex are likely to link neighboring neurons with similar numerosity preference, which would allow 315 parietal GABA to influence numerosity discrimination and numerosity illusion (Almeida et al., 2007; Bosten et 316 al., 2010; Dormal et al., 2008; Pinel et al., 2004). Almeida, A., Arantes, J., & Machado, A. (2007). Numerosity discrimination in preschool children. Journal of 327 the experimental analysis of behavior, 88(3), 339-354. 328 Bachtiar, V., Near, J., Johansen-Berg, H., & Stagg, C. J. (2015). Modulation of GABA and resting state 329 functional connectivity by transcranial direct current stimulation. Elife, 4, e08789. 330 Ben-Yishai, R., Bar-Or, R. L., & Sompolinsky, H. (1995). Theory of orientation tuning in visual cortex. 331 Proceedings of the National Academy of Sciences, 92(9), 3844-3848. 332 Ben-Yishai, R., Bar-Or, R. L., & Sompolinsky, H. (1995). Theory of orientation tuning in visual cortex. 331 Proceedings of the National Academy of Sciences 92(9) 3844-3848 332 Bock, D. D., Lee, W. C. A., Kerlin, A. M., Andermann, M. L., & Reid, R. C. (2011). Network anatomy and in 333 vivo physiology of visual cortical neurons. Nature, 471(7337), 177-182. 334 Bosten, J. M., & Mollon, J. D. (2010). Is there a general trait of susceptibility to simultaneous contrast? Vision 335 research, 50(17), 1656-1664. 336 Bueti, D., & Walsh, V. (2009). The parietal cortex and the representation of time, space, number and other 337 magnitudes. Philosophical Transactions of the Royal Society of London B: Biological Sciences, 364(1525), 338 1831-1840. 339 Burr, D., Morrone, C., & Maffei, L. (1981). Intra-cortical inhibition prevents simple cells from responding to 340 textured visual patterns. Experimental Brain Research, 43(3-4), 455-458. 341 Cannon, M. W., & Fullenkamp, S. C. (1996). A model for inhibitory lateral interaction effects in perceived 342 contrast. Vision research, 36(8), 1115-1125. 343 Caputi, A., Melzer, S., Michael, M., & Monyer, H. (2013). The long and short of GABAergic neurons. Current 344 opinion in neurobiology, 23(2), 179-186. 345 Chavane, F., Sharon, D., Jancke, D., Marre, O., Frégnac, Y., & Grinvald, A. (2011). Lateral spread of 346 orientation selectivity in V1 is controlled by intracortical cooperativity. Frontiers in Systems Neuroscience, 5, 4. 347 Chen, J., & Kriegstein, A. R. (2015). A GABAergic projection from the zona incerta to cortex promotes cortical 348 neuron development. Science, 350(6260), 554-558. 349 Chklovskii, D. B., & Koulakov, A. A. (2004). Maps in the brain: what can we learn from them? Annu. Rev. 350 Neurosci., 27, 369-392. 351 Clifford, C. W. (2014). The tilt illusion: Phenomenology and functional implications. Vision research, 104, 3-11. 352 Constantinescu, A. O., O’Reilly, J. X., & Behrens, T. E. (2016). Organizing conceptual knowledge in humans 353 with a gridlike code. Science, 352(6292), 1464-1468. While the posterior (e.g., occipital, parietal) part of the cortex 317 is involved in sensory processing, a topographic map of conceptual knowledge was discovered in prefrontal 318 cortex, suggesting a potential role of frontal GABA in conceptual categorization (Constantinescu et al., 2016). It 319 would be of interest for future studies to test the links between parietal GABA and numerosity perception, as 320 well as between frontal GABA and conceptual categorization. 321 322 11 323 REFERENCES 324 Adams, D. L., Sincich, L. C., & Horton, J. C. (2007). Complete pattern of ocular dominance columns in human 325 primary visual cortex. The Journal of Neuroscience, 27(39), 10391-10403. 326 Edden, R. A., & Barker, P. B. (2007). Spatial effects in the detection of γ-aminobutyric acid: Improved 362 sensitivity at high fields using inner volume saturation. Magnetic Resonance in Medicine, 58(6), 1276-1282. 363 Edden, R. A., & Barker, P. B. (2007). Spatial effects in the detection of γ-aminobutyric acid: Improved 362 sensitivity at high fields using inner volume saturation. Magnetic Resonance in Medicine, 58(6), 1276-1282. 363 Edden, R. A., Crocetti, D., Zhu, H., Gilbert, D. L., & Mostofsky, S. H. (2012). Reduced GABA concentration in 364 attention-deficit/hyperactivity disorder. Archives of general psychiatry, 69(7), 750-753. 365 Edden, R. A., Muthukumaraswamy, S. D., Freeman, T. C., & Singh, K. D. (2009). Orientation discrimination 366 performance is predicted by GABA concentration and gamma oscillation frequency in human primary visual 367 cortex. The Journal of Neuroscience, 29(50), 15721-15726. 368 Edden, R. A., Muthukumaraswamy, S. D., Freeman, T. C., & Singh, K. D. (2009). Orientation discrimination 366 performance is predicted by GABA concentration and gamma oscillation frequency in human primary visual 367 t Th J l f N i 29(50) 15721 15726 368 Evans, C. J., McGonigle, D. J., & Edden, R. A. E. (2010). Diurnal stability of γ‐aminobutyric acid concentration 369 in visual and sensorimotor cortex. Journal of Magnetic Resonance Imaging, 31(1), 204-209. 370 Eysel, U. T., Crook, J. M., & Machemer, H. F. (1990). GABA-induced remote inactivation reveals cross- 371 orientation inhibition in the cat striate cortex. Experimental brain research, 80(3), 626-630. 372 Fitzpatrick, D. (2000). Seeing beyond the receptive field in primary visual cortex. Current opinion in 373 neurobiology, 10(4), 438-443. 374 Gilbert, C. D., Das, A., Ito, M., Kapadia, M., & Westheimer, G. (1996). Spatial integration and cortical 375 dynamics. Proceedings of the National Academy of Sciences, 93(2), 615-622. 376 Gold, J. I., & Ding, L. (2013). How mechanisms of perceptual decision-making affect the psychometric 377 function. Progress in neurobiology, 103, 98-114. 378 Harvey, B. M., Fracasso, A., Petridou, N., & Dumoulin, S. O. (2015). Topographic representations of object 379 size and relationships with numerosity reveal generalized quantity processing in human parietal 380 cortex. Proceedings of the National Academy of Sciences, 112(44), 13525-13530. 381 Harvey, B. M., Klein, B. P., Petridou, N., & Dumoulin, S. O. (2013). Topographic representation of numerosity 382 in the human parietal cortex. Science, 341(6150), 1123-1126. 383 Ikeda, K., & Bekkers, J. M. (2009). Counting the number of releasable synaptic vesicles in a presynaptic 384 terminal. 354 Dammerman, R. S., Flint, A. C., Noctor, S., & Kriegstein, A. R. (2000). An excitatory GABAergic plexus in 355 developing neocortical layer 1. Journal of Neurophysiology, 84(1), 428-434. 356 Dammerman, R. S., Flint, A. C., Noctor, S., & Kriegstein, A. R. (2000). An excitatory GABAergic plexus in 355 developing neocortical layer 1 Journal of Neurophysiology 84(1) 428-434 356 12 Dechent, P., & Frahm, J. (2000). Direct mapping of ocular dominance columns in human primary visual 357 cortex. Neuroreport, 11(14), 3247-3249. 358 Dehaene, S., & Cohen, L. (2007). Cultural recycling of cortical maps. Neuron, 56(2), 384-398. 359 Dormal, V., Andres, M., & Pesenti, M. (2008). Dissociation of numerosity and duration processing in the left 360 intraparietal sulcus: a transcranial magnetic stimulation study. Cortex, 44(4), 462-469. 361 Kinoshita, M., & Komatsu, H. (2001). Neural representation of the luminance and brightness of a uniform 396 surface in the macaque primary visual cortex. Journal of neurophysiology, 86(5), 2559-2570. 397 Lehmann, K., Steinecke, A., & Bolz, J. (2012). GABA through the ages: regulation of cortical function and 398 plasticity by inhibitory interneurons. Neural plasticity, 2012. 399 Li, Y., Lu, H., Cheng, P. L., Ge, S., Xu, H., Shi, S. H., & Dan, Y. (2012). Clonally related visual cortical 400 neurons show similar stimulus feature selectivity. Nature, 486(7401), 118-121. 401 Lukasiewicz, P. D., & Shields, C. R. (1998). A diversity of GABA receptors in the retina. Seminars in cell & 402 developmental biology. Academic Press. 403 Lunghi, C., Emir, U. E., Morrone, M. C., & Bridge, H. (2015). Short-term monocular deprivation alters GABA 404 in the adult human visual cortex. Current Biology, 25(11), 1496-1501. 405 Marenco, S., et al. (2010). Genetic modulation of GABA levels in the anterior cingulate cortex by GAD1 and 406 COMT. Neuropsychopharmacology, 35(8), 1708-1717. 407 Menon, R. S., Ogawa, S., Strupp, J. P., & Uǧurbil, K. (1997). Ocular dominance in human V1 demonstrated by 408 functional magnetic resonance imaging. Journal of Neurophysiology, 77(5), 2780-2787. 409 Mescher, M., Merkle, H., Kirsch, J., Garwood, M., & Gruetter, R. (1998). Simultaneous in vivo spectral editing 410 and water suppression. NMR in Biomedicine, 11(EPFL-ARTICLE-177509), 266-272. 411 Morrone, M. C., Burr, D. C., & Speed, H. D. (1987). Cross-orientation inhibition in cat is GABA 412 mediated. Experimental Brain Research, 67(3), 635-644. 413 Moult, P. R. (2009). Neuronal glutamate and GABAA receptor function in health and disease. Biochemical 414 Society Transactions, 37(6), 1317-1322. 415 Mullins, P. G., McGonigle, D. J., O'Gorman, R. L., Puts, N. A., Vidyasagar, R., Evans, C. J., & Edden, R. A. 416 (2014). Current practice in the use of MEGA-PRESS spectroscopy for the detection of GABA. Neuroimage, 86, 417 43-52. 418 (2014). Current practice in the use of MEGA-PRESS spectroscopy for the detection of GABA. Neuroimage, 86, 417 43-52. 418 Murdoch, J. B., & Dydak, U. (2011). Modeling MEGA-PRESS macromolecules for a better grasp of GABA. 419 Proc Intl Soc Mag Reson Med, 19, 1394. 420 Near, J., Andersson, J., Maron, E., Mekle, R., Gruetter, R., Cowen, P., & Jezzard, P. (2013). Unedited in vivo 421 detection and quantification of γ‐aminobutyric acid in the occipital cortex using short‐TE MRS at 3 T. NMR in 422 Biomedicine, 26(11), 1353-1362. Proceedings of the National Academy of Sciences, 106(8), 2945-2950. 385 Ikeda, K., & Bekkers, J. M. (2009). Counting the number of releasable synaptic vesicles in a presynaptic 384 terminal. Proceedings of the National Academy of Sciences, 106(8), 2945-2950. 385 Ikeda, K., & Bekkers, J. M. (2009). Counting the number of releasable synaptic vesicles in a presynaptic 384 i l P di f h N i l A d f S i 106(8) 2945 2950 385 Jinno, S., Klausberger, T., Marton, L. F., Dalezios, Y., & Somogyi, P. (2007). Neuronal diversity in GABAergic 386 long-range projections from the hippocampus. The Journal of neuroscience, 27(33), 8790-8804. 387 Kadosh, R. C., & Walsh, V. (2009). Numerical representation in the parietal lobes: abstract or not abstract? 388 Behavioral and brain sciences, 32(3-4), 313-328. 389 Kaschube, M., Schnabel, M., Löwel, S., Coppola, D. M., White, L. E., & Wolf, F. (2010). Universality in the 390 evolution of orientation columns in the visual cortex. science, 330(6007), 1113-1116. 391 Kaschube, M., Schnabel, M., Löwel, S., Coppola, D. M., White, L. E., & Wolf, F. (2010). Universality in the 390 evolution of orientation columns in the visual cortex science 330(6007) 1113 1116 391 13 Katzner, S., Busse, L., & Carandini, M. (2011). GABAA inhibition controls response gain in visual cortex. The 392 Journal of neuroscience, 31(16), 5931-5941. 393 Kapadia, M. K., Westheimer, G., & Gilbert, C. D. (2000). Spatial distribution of contextual interactions in 394 primary visual cortex and in visual perception. Journal of neurophysiology, 84(4), 2048-2062. 395 423 Near, J., Ho, Y. C. L., Sandberg, K., Kumaragamage, C., & Blicher, J. U. (2014). Long-term reproducibility of 424 GABA magnetic resonance spectroscopy. Neuroimage, 99, 191-196. 425 14 14 Near, J., Simpson, R., Cowen, P., & Jezzard, P. (2011). Efficient γ‐aminobutyric acid editing at 3T without 426 macromolecule contamination: MEGA-SPECIAL. NMR in biomedicine, 24(10), 1277-1285. 427 Nieder, A., & Dehaene, S. (2009). Representation of number in the brain. Annual review of neuroscience, 32, 428 185-208. 429 Ogorman, R. L., et al. (2011). In vivo detection of GABA and glutamate with MEGA-PRESS: Reproducibility 430 and gender effects. Journal of magnetic resonance imaging, 33(5), 1262-1267. 431 Orban, G. A., & Vogels, R. (1998). The neuronal machinery involved in successive orientation discrimination. 432 Progress in neurobiology, 55(2), 117-147. 433 Perna, A., Tosetti, M., Montanaro, D., & Morrone, M. C. (2005). Neuronal mechanisms for illusory brightness 434 perception in humans. Neuron, 47(5), 645-651. 435 Picardo, M. A., et al. (2011). Pioneer GABA cells comprise a subpopulation of hub neurons in the developing 436 hippocampus. Neuron, 71(4), 695-709. 437 Pinel, P., Piazza, M., Le Bihan, D., & Dehaene, S. (2004). Distributed and overlapping cerebral representations 438 of number, size, and luminance during comparative judgments. Neuron, 41(6), 983-993. 439 Priebe, N. J., & Ferster, D. (2008). Inhibition, spike threshold, and stimulus selectivity in primary visual 440 cortex. Neuron, 57(4), 482-497. 441 Ringach, D. L., Shapley, R. M., & Hawken, M. J. (2002). Orientation selectivity in macaque V1: diversity and 442 laminar dependence. The Journal of neuroscience, 22(13), 5639-5651. 443 Roitman, J. D., Brannon, E. M., & Platt, M. L. (2007). Monotonic coding of numerosity in macaque lateral 444 intraparietal area. PLoS biology, 5(8), e208. 445 Roitman, J. D., Brannon, E. M., & Platt, M. L. (2012). Representation of numerosity in posterior parietal 446 cortex. Frontiers in integrative neuroscience, 6, 25. 447 Sandberg, K., Blicher, J. U., Dong, M. Y., Rees, G., Near, J., & Kanai, R. (2014). Occipital GABA correlates 448 with cognitive failures in daily life. NeuroImage, 87, 55-60. 449 Sandberg, K., Blicher, J. U., Del Pin, S. H., Andersen, L. M., Rees, G., & Kanai, R. (2016). Improved estimates 450 for the role of grey matter volume and GABA in bistable perception. Cortex, 83, 292-305. 451 Schwartz, O., Hsu, A., & Dayan, P. (2007). Space and time in visual context. Nature Review Neuroscience, 8(7), 452 522-535. 453 Shen, J. (2003). On the foundations of vision modeling: I. Weber’s law and Weberized TV restoration. Physica 454 D: Nonlinear Phenomena, 175(3), 241-251. 455 Simpson, R., Devenyi, G. A., Jezzard, P., Hennessy, T. J., & Near, J. (2015). Advanced processing and 456 simulation of MRS data using the FID appliance. Magnetic resonance in medicine. 457 Smith, M. A., Bair, W., & Movshon, J. A. (2006). Dynamics of suppression in macaque primary visual 458 cortex. Journal of Neuroscience, 26(18), 4826-4834. Song, C., Schwarzkopf, D. S., & Rees, G. (2013). Variability in visual cortex size reflects tradeoff between local 465 orientation sensitivity and global orientation modulation. Nature communications, 4. 466 Song, C., Schwarzkopf, D. S., Kanai, R., & Rees, G. (2015). Neural population tuning links visual cortical 467 anatomy to human visual perception. Neuron, 85(3), 641-656. 468 Stettler, D. D., Das, A., Bennett, J., & Gilbert, C. D. (2002). Lateral connectivity and contextual interactions in 469 macaque primary visual cortex. Neuron, 36(4), 739-750. 470 Stettler, D. D., Das, A., Bennett, J., & Gilbert, C. D. (2002). Lateral connectivity and contextual interactions in 469 macaque primary visual cortex. Neuron, 36(4), 739-750. 470 Swindale, N. V. (2000). How many maps are there in visual cortex? Cerebral cortex, 10(7), 633-643. 471 Taniguchi, H., et al. (2011). A resource of Cre driver lines for genetic targeting of GABAergic neurons in 472 cerebral cortex. Neuron, 71(6), 995-1013. 473 Van Loon, A. M., Knapen, T., Scholte, H. S., John-Saaltink, E. S., Donner, T. H., & Lamme, V. A. (2013). 474 GABA shapes the dynamics of bistable perception. Current Biology, 23(9), 823-827. 475 Vogels, R., & Orban, G. A. (1986). Decision factors affecting line orientation judgments in the method of single 476 stimuli. Attention, Perception, and Psychophysics, 40(2), 74-84. 477 Walsh, V. (2003). A theory of magnitude: common cortical metrics of time, space and quantity. Trends in 478 Cognitive Sciences, 7(11), 483-488. 479 Wolf, F., & Geisel, T. (1998). Spontaneous pinwheel annihilation during visual development. Nature, 395 480 (6697), 73-78. 481 Wu, S. M. (2010). Synaptic organization of the vertebrate retina: general principles and species-specific 482 variations. Investigative Ophthalmology and Visual Science, 51(3), 1264-1274. 483 Yacoub, E., Harel, N., & Uğurbil, K. (2008). High-field fMRI unveils orientation columns in humans. 484 Proceedings of the National Academy of Sciences, 105(30), 10697-10612. 485 Yoon, J. H., Maddock, R. J., Rokem, A., Silver, M. A., Minzenberg, M. J., Ragland, J. D., & Carter, C. S. 486 (2010). GABA concentration is reduced in visual cortex in schizophrenia and correlates with orientation- 487 specific surround suppression. The Journal of Neuroscience, 30(10), 3777-3781. 488 Yoon, J. H., Maddock, R. J., Rokem, A., Silver, M. A., Minzenberg, M. J., Ragland, J. D., & Carter, C. S. 486 (2010). 459 15 15 Somers, D. C., Nelson, S. B., & Sur, M. (1995). An emergent model of orientation selectivity in cat visual 460 cortical simple cells. The Journal of neuroscience, 15(8), 5448-5465. 461 Somers, D. C., Nelson, S. B., & Sur, M. (1995). An emergent model of orientation selectivity in cat visu 460 ti l i l ll Th J l f i 15(8) 5448 5465 461 Song, C., Schwarzkopf, D. S., Lutti, A., Li, B., Kanai, R., & Rees, G. (2013). Effective connectivity within 462 human primary visual cortex predicts interindividual diversity in illusory perception. The Journal of 463 Neuroscience, 33(48), 18781-18791. 464 Song, C., Schwarzkopf, D. S., Lutti, A., Li, B., Kanai, R., & Rees, G. (2013). Effective connectivity within 462 human primary visual cortex predicts interindividual diversity in illusory perception. The Journal of 463 Neuroscience 33(48) 18781-18791 464 Figure 2. Parietal and occipital GABA. Parietal and occipital GABA levels were plotted against each other, 496 illustrating a lack of inter-individual correlation between these two variables. Each data point represents a 497 participant. Statistics are Pearson’s correlation and bootstrap results. 498 Figure 2. Parietal and occipital GABA. Parietal and occipital GABA levels were plotted against each other, 496 illustrating a lack of inter-individual correlation between these two variables. Each data point represents a 497 participant. Statistics are Pearson’s correlation and bootstrap results. 498 Figure 2. Parietal and occipital GABA. Parietal and occipital GABA levels were plotted against each other, 496 illustrating a lack of inter-individual correlation between these two variables. Each data point represents a 497 participant. Statistics are Pearson’s correlation and bootstrap results. 498 Figure 3. GABA and size illusion. In the Ebbinghaus illusion, two physically identical central circles appear to 499 have different perceived size as a result of the surrounding context of either smaller or larger circles. The 500 magnitude of Ebbinghaus illusion for each participant was plotted in semi-log graph against their parietal or 501 occipital GABA level, illustrating a positive correlation between size illusion magnitude and parietal GABA 502 level, as well as a lack of significant correlation between size illusion magnitude and occipital GABA level. 503 Each data point represents a participant. Statistics are Pearson’s correlation and bootstrap results. 504 Figure 3. GABA and size illusion. In the Ebbinghaus illusion, two physically identical central circles appear to 499 have different perceived size as a result of the surrounding context of either smaller or larger circles. The 500 magnitude of Ebbinghaus illusion for each participant was plotted in semi-log graph against their parietal or 501 occipital GABA level, illustrating a positive correlation between size illusion magnitude and parietal GABA 502 level, as well as a lack of significant correlation between size illusion magnitude and occipital GABA level. 503 Each data point represents a participant. Statistics are Pearson’s correlation and bootstrap results. 504 Figure 4. GABA and orientation illusion. In the tilt illusion, two physically identical central gratings appear to 505 have different perceived orientation as a result of their immediate surroundings. GABA concentration is reduced in visual cortex in schizophrenia and correlates with orientation- 487 specific surround suppression The Journal of Neuroscience 30(10) 3777 3781 488 489 16 16 FIGURE LEGENDS 490 Figure 1. MRS Spectra. MRS measure of resting GABA was acquired in separate experiment runs, from a 491 parietal voxel (blue) placed on the anterior part of the superior parietal lobe with its anterior border parallel to 492 the postcentral gyrus, and a occipital voxel (red) placed to cover the calcarine sulcus bilaterally with its anterior 493 border in alignment with the parietal-occipital sulcus. Examples of MRS spectra from ten randomly selected 494 participants are shown. The GABA peak is seen at 3 ppm and the inverted NAA peak at around 2 ppm. 495 Figure 1. MRS Spectra. MRS measure of resting GABA was acquired in separate experiment runs, from a 491 parietal voxel (blue) placed on the anterior part of the superior parietal lobe with its anterior border parallel to 492 the postcentral gyrus, and a occipital voxel (red) placed to cover the calcarine sulcus bilaterally with its anterior 493 border in alignment with the parietal-occipital sulcus. Examples of MRS spectra from ten randomly selected 494 participants are shown. The GABA peak is seen at 3 ppm and the inverted NAA peak at around 2 ppm. 495 The magnitude of tilt illusion 506 for each participant was plotted in semi-log graph against their parietal or occipital GABA level, illustrating a 507 positive correlation between orientation illusion magnitude and occipital GABA level, as well as a lack of 508 significant correlation between orientation illusion magnitude and parietal GABA level. Each data point 509 represents a participant. Statistics are Pearson’s correlation and bootstrap results. 510 Figure 4. GABA and orientation illusion. In the tilt illusion, two physically identical central gratings appear to 505 have different perceived orientation as a result of their immediate surroundings. The magnitude of tilt illusion 506 for each participant was plotted in semi-log graph against their parietal or occipital GABA level, illustrating a 507 positive correlation between orientation illusion magnitude and occipital GABA level, as well as a lack of 508 significant correlation between orientation illusion magnitude and parietal GABA level. Each data point 509 represents a participant. Statistics are Pearson’s correlation and bootstrap results. 510 Figure 4. GABA and orientation illusion. In the tilt illusion, two physically identical central gratings appear to 505 have different perceived orientation as a result of their immediate surroundings. The magnitude of tilt illusion 506 for each participant was plotted in semi-log graph against their parietal or occipital GABA level, illustrating a 507 positive correlation between orientation illusion magnitude and occipital GABA level, as well as a lack of 508 significant correlation between orientation illusion magnitude and parietal GABA level. Each data point 509 represents a participant. Statistics are Pearson’s correlation and bootstrap results. 510 Figure 5. GABA and brightness illusion. In the simultaneous contrast illusion, two physically identical central 511 circles appear to have different brightness as a result of their immediate surroundings. The magnitude of 512 simultaneous contrast illusion for each participant was plotted in semi-log graph against their parietal or 513 occipital GABA level, illustrating a lack of significant correlation between brightness illusion magnitude and 514 either parietal or occipital GABA level. Each data point represents a participant. Statistics are Pearson’s 515 correlation and bootstrap results. 516 17 17 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 1 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 2 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 3 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 4 GABA NAA Participant 5 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 6 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 7 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 8 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 9 GABA NAA Participant 10 Parietal Voxel Occipital Voxel 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 1 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 2 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 3 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 4 GABA NAA Participant 5 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 6 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 7 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 8 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 9 GABA NAA Participant 10 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 1 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 2 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 3 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 6 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 7 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 8 Parietal Voxel Occipital Voxel 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 1 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 2 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 3 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 6 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 7 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 8 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 1 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 6 Participant 6 Participant 2 Participant 7 Participant 7 1 2 3 4 5 Frequency (ppm) GABA NAA p 1 2 3 4 5 Frequency (ppm) GABA NAA p Participant 8 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 4 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 9 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 4 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 9 Participant 9 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 5 1 2 3 4 5 Frequency (ppm) GABA NAA Participant 10 r = -0.066 [-0.372 0.250], p = 0.730, N = 30 Occipital GABA (GABA+/Cr Ratio) 0.22 0.28 0.34 0.40 Parietal GABA (GABA+/Cr Ratio) 0.20 0.24 0.28 0.32 r = -0.066 [-0.372 0.250], p = 0.730, N = 30 Occipital GABA (GABA+/Cr Ratio) 0.22 0.28 0.34 0.40 Parietal GABA (GABA+/Cr Ratio) 0.20 0.24 0.28 0.32 r = -0.066 [-0.372 0.250], p = 0.730, N = 30 Parietal GABA (GABA+/Cr Ratio) diameter: 1.0 deg of visual angle Size Illusion Magnitude (deg) Parietal GABA (GABA+/Cr Ratio) 0.20 0.24 0.28 0.32 r = 0.395 [0.117 0.610], p = 0.031, N = 30 0.13 0.21 0.34 0.55 Size Illusion Magnitude (deg) Occipital GABA (GABA+/Cr Ratio) 0.22 0.28 0.34 0.40 r = -0.038 [-0.317 0.250], p = 0.841, N = 30 0.13 0.21 0.34 0.55 diameter: 2.0 deg of visual angle diameter: 0.2 deg of visual angle diameter: 1.0 deg of visual angle diameter: 2.0 deg of visual angle diameter: 0.2 deg of visual angle Size Illusion Magnitude (deg) Parietal GABA (GABA+/Cr Ratio) 0.20 0.24 0.28 0.32 r = 0.395 [0.117 0.610], p = 0.031, N = 30 0.13 0.21 0.34 0.55 Size Illusion Magnitude (deg) Occipital GABA (GABA+/Cr Ratio) 0.22 0.28 0.34 0.40 r = -0.038 [-0.317 0.250], p = 0.841, N = 30 0.13 0.21 0.34 0.55 Size Illusion Magnitude (deg) Occipital GABA (GABA+/Cr Ratio) 0.22 0.28 0.34 0.40 r = -0.038 [-0.317 0.250], p = 0.841, N = 30 0.13 0.21 0.34 0.55 Size Illusion Magnitude (deg) Parietal GABA (GABA+/Cr Ratio) 0.20 0.24 0.28 0.32 r = 0.395 [0.117 0.610], p = 0.031, N = 30 0.13 0.21 0.34 0.55 Brightness Illusion Magnitude (%) Parietal GABA (GABA+/Cr Ratio) 0.20 0.24 0.28 0.32 r = -0.149 [-0.456 0.163], p = 0.431, N = 30 1.76 4.66 12.3 32.7 Brightness Illusion Magnitude (%) Occipital GABA (GABA+/Cr Ratio) 0.22 0.28 0.34 0.40 r = -0.017 [-0.377 0.391], p = 0.927, N = 30 1.76 4.66 12.3 32.7 luminance: 100% luminance: 0% luminance: 50% luminance: 100% luminance: 0% luminance: 50% 456 0.163], p = 0.431, N = 30 r = -0.017 [-0.377 0.391 luminance: 100% luminance: 0% luminance: 50% Brightness Illusion Magnitude (%) Parietal GABA (GABA+/Cr Ratio) 0.20 0.24 0.28 0.32 r = -0.149 [-0.456 0.163], p = 0.431, N = 30 1.76 4.66 12.3 32.7 Brightness Illusion Magnitude (%) Occipital GABA (GABA+/Cr Ratio) 0.22 0.28 0.34 0.40 r = -0.017 [-0.377 0.391], p = 0.927, N = 30 1.76 4.66 12.3 32.7 Brightness Illusion Magnitude (%) Occipital GABA (GABA+/Cr Ratio) 0.22 0.28 0.34 0.40 r = -0.017 [-0.377 0.391], p = 0.927, N = 30 1.76 4.66 12.3 32.7 Brightness Illusion Magnitude (%) Parietal GABA (GABA+/Cr Ratio) 0.20 0.24 0.28 0.32 r = -0.149 [-0.456 0.163], p = 0.431, N = 30 1.76 4.66 12.3 32.7 r = -0.017 [-0.377 0.391], p = 0.927, N = 30 r = -0.149 [-0.456 0.163], p = 0.431, N = 30
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Dual RNA-Seq Uncovers Metabolic Amino Acids Dependency of the Intracellular Bacterium Piscirickettsia salmonis Infecting Atlantic Salmon
Frontiers in microbiology
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ORIGINAL RESEARCH published: 27 November 2018 doi: 10.3389/fmicb.2018.02877 Citation: Valenzuela-Miranda D and Gallardo-Escárate C (2018) Dual RNA-Seq Uncovers Metabolic Amino Acids Dependency of the Intracellular Bacterium Piscirickettsia salmonis Infecting Atlantic Salmon. Front. Microbiol. 9:2877. doi: 10.3389/fmicb.2018.02877 Dual RNA-Seq Uncovers Metabolic Amino Acids Dependency of the Intracellular Bacterium Piscirickettsia salmonis Infecting Atlantic Salmon Diego Valenzuela-Miranda and Cristian Gallardo-Escárate* Diego Valenzuela-Miranda and Cristian Gallardo-Escárate* Laboratory of Biotechnology and Aquatic Genomics, Interdisciplinary Center for Aquaculture Research, University of Concepción, Concepción, Chile High-throughput sequencing technologies have offered the possibility to understand the complexity of the transcriptomic responses of an organism during a wide variety of biological scenarios, such as the case of pathogenic infections. Recently, the simultaneous sequencing of both pathogen and host transcriptomes (dual RNA-seq) during the infection has become a promising approach to uncover the complexity of the host–pathogen interactions. In this study, through a double rRNA depletion and RNA sequencing protocols, we simultaneously analyzed the transcriptome of the intracellular bacterium Piscirickettsia salmonis and its host the Atlantic salmon (Salmo salar) during the course of the infection. Beyond canonical host immune-related response and pathogen virulent factors, both bacteria and host displayed a large number of genes associated with metabolism and particularly related with the amino acid metabolism. Notably, genome-wide comparison among P. salmonis genomes and different fish pathogens genomes revealed a lack of the biosynthetic pathway for several amino acids such as valine, leucine, and isoleucine. To support this finding, in vitro experiments evidenced that when these amino acids are restricted the bacterial growth dynamics is significantly affected. However, this condition is phenotypically reversed when the amino acids are supplemented in the bacterial growth medium. Based on our results, a metabolic dependency of P. salmonis on S. salar amino acids is suggested, which could imply novel mechanisms of pathogenesis based on the capacity to uptake nutrients from the host. Overall, dual transcriptome sequencing leads to the understanding of host–pathogen interactions from a different perspective, beyond biological processes related to immunity. Valenzuela-Miranda D and Gallardo-Escárate C (2018) Dual RNA-Seq Uncovers Metabolic Amino Acids Dependency of the Intracellular Bacterium Piscirickettsia salmonis Infecting Atlantic Salmon. Front. Microbiol. 9:2877. doi: 10.3389/fmicb.2018.02877 Keywords: dual RNA-seq, Piscirickettsia salmonis, Atlantic salmon, nutritional immunity, metabolic dependency, amino acids Edited by: Edited by: Suhelen Egan, University of New South Wales, Australia Reviewed by: Weiming Sun, Yantai University, China Chang Chen, University of Illinois at Chicago, United States Khalil Eslamloo, Memorial University of Newfoundland, Canada *Correspondence: Cristian Gallardo-Escárate crisgallardo@udec.cl; crisgallardo@oceanografia.udec.cl Specialty section: This article was submitted to Microbial Symbioses, a section of the journal Frontiers in Microbiology Received: 07 August 2018 Accepted: 09 November 2018 Published: 27 November 2018 Keywords: dual RNA-seq, Piscirickettsia salmonis, Atlantic salmon, nutritional immunity, metabolic dependency, amino acids INTRODUCTION High-throughput sequencing technologies applied to transcriptomic studies (RNA-Seq) have offered the possibility to understand complex molecular responses under different biological scenarios. Among them, a pathogenic infection entails a deep transcriptomic remodeling of the host to promote the pathogenic clearance; in turn, pathogens display the expression of different November 2018 | Volume 9 | Article 2877 Frontiers in Microbiology | www.frontiersin.org Dual RNA-Seq of P. salmonis Infecting S. salar Valenzuela-Miranda and Gallardo-Escárate pathogen can evade host immune response are still unclear. Due to the high prevalence, negative impact and scientific interest on this pathogen, different efforts have tried to understand salmonids defensive mechanism against P. salmonis and how the bacteria overcome this response. Host transcriptomic response has been mainly associated with a regulation of genes involved in the innate immunity, apoptosis, different signaling pathways, endocytosis, non-coding RNAs and iron metabolism among others (Rise et al., 2004; Tacchi et al., 2011; Pulgar et al., 2015; Valenzuela-Miranda and Gallardo-Escarate, 2016; Valenzuela-Miranda et al., 2017). On the other hand, P. salmonis transcriptomic response has been assessed after the in vitro infection in Sf21 cell lines (Machuca and Martinez, 2016). Although different genes associated with the type IV secretion and iron acquisition system were identified, it remains unexplored how P. salmonis transcriptome is modulated during the infection. Due to this, we explore a dual RNA-Seq approach to unravel novel mechanisms of interactions during the infection of P. salmonis on the Atlantic salmon. A special emphasis was placed in bacterial gene expression, since transcriptional response of the Atlantic salmon against P. salmonis have been widely described previously (Tacchi et al., 2011; Pulgar et al., 2015; Valenzuela-Miranda and Gallardo-Escarate, 2016; Tarifeno-Saldivia et al., 2017). Beyond canonical pathogenic and immune related-genes, our results evidenced a common transcriptomic response between host and pathogen associated with the amino acid metabolism. Further analyses revealed a lack of P. salmonis genes associated with different amino acids biosynthetic pathways and the importance of the availability of some amino acids for the bacterial growth medium. We hypothesize metabolic amino acids dependency of P. salmonis on S. salar, which could imply novel mechanisms of pathogenesis based on the capacity to uptake nutrients from the host and capacity of the host to regulate the availability of free amino acids. genes to grant their survival and replicate within the host. INTRODUCTION In this context, the simultaneous analysis of host and pathogen transcriptomes (dual RNA-Seq) during their interaction can reveal novel aspects of the infective process (Westermann et al., 2017). Initially, this approach was limited to viral, fungal and parasitic infections, where the pathogen resembles host transcripts (Tierney et al., 2012; Strong et al., 2013; Choi et al., 2014; Pittman et al., 2014) and scarcely reported in bacterial models (Westermann et al., 2012). However, the improvement of high-throughput sequencing and the development of novel RNA capture/depletion methods offer a promising opportunity to also expand this approach to bacterial infections (Westermann et al., 2016). Although most dual RNA-seq approaches applied in bacterial infections have been exploratory, some of them have unraveled novel mechanisms of host–pathogen interaction. For instance, a dual RNA-seq was used to discover a possible strategy employed by Chlamydia trachomatis for the in vitro infection of human epithelial cells based on an early iron acquisition and a host immune depletion strategy (Humphrys et al., 2013). Furthermore, the simultaneous transcriptome analysis of the Gram-negative bacterium Haemophilus influenza during the infection of mucosal epithelial cells revealed the importance of the host oxidative response and the mechanisms employed by the bacteria to overcome this adverse environment (Baddal et al., 2016). Likewise, the co-transcriptomic analysis of the uropathogenic Escherichia coli (UPEC) and its host evidenced that while host transcriptomic response was similar to different bacterial strains, different expression patterns were identified in UPEC strains with contrasting pathogenic effects (Mavromatis et al., 2015). These results were used to reveal novel insights into the mechanisms employed by the bacteria for the intra-macrophage survival. Moreover, a dual RNA-Seq was used to characterize the regulatory role of small RNAs (sRNAs) in Salmonella enterica infection. Here, researchers identified bacterial sRNA involved in the regulation of both host and pathogenic genes, revealing the hidden roles of S. enterica transcripts during the pathogenesis (Westermann et al., 2016). Simultaneous profiling of host-pathogen transcriptomes has become a powerful approach tool to unravel key aspects during the infection process. In the present study, we apply a dual RNA-Seq approach to reveal novel aspects of the infective process of the intracellular bacterium Piscirickettsia salmonis during the infection on the Atlantic salmon (Salmo salar). Frontiers in Microbiology | www.frontiersin.org Experimental Design Experimental Design Atlantic salmons (154.7 ± 13.5g) were obtained from a commercial farm located at Puerto Montt, Chile and transferred to the Marine Biology Station of the University of Concepción (Dichato, Chile). Here, individuals were randomly screened to discard the presence of different pathogens commonly present salmonid aquaculture. After quarantine, individuals were randomly divided into two independent marine water-based recirculating lines, each containing five 370 L tanks. For each line, three tanks were used for sampling (six in total), one tank was used to record mortality (two in total) and the remaining tank was not considered in this experiment. A total of 50 individuals per tank were maintained during an acclimation period of 14 days before the challenge. After this period, each individual was anesthetized and intraperitoneally injected with 0.2 ml of P. salmonis (EM-90 strain) containing 1 × 106 bacteria per dose, as previously standardized. Later, samples were collected from infected individuals at 3, 7, and 14 days post Piscirickettsia salmonis is a facultative intracellular gram-negative bacterium that causes the salmonid rickettsial septicemia (SRS), a severe systemic disease responsible for up to 85% of the infectious moralities in farmed salmons in Chile. Just in this country, the economic losses associated with this pathogen has been estimated in around US$100 million per year (Smith et al., 1997; Bravo and Midtlyng, 2007; Pulgar et al., 2015), becoming one of the main concerns for the industry (Mauel and Miller, 2002). Beyond this negative impact, perhaps one of the most remarkable features of P. salmonis is its capability to infect and replicate within host immune cells, such as in macrophages (McCarthy et al., 2008; Rajas et al., 2009; Ramirez et al., 2015). In this context, the mechanism whereby this November 2018 | Volume 9 | Article 2877 Frontiers in Microbiology | www.frontiersin.org 2 Dual RNA-Seq of P. salmonis Infecting S. salar Valenzuela-Miranda and Gallardo-Escárate infection (dpi). Head kidney and spleen tissues were collected from two individuals of each sampling tank (12 individuals per point) and stored in RNA later solution (Ambion, United States) at −80◦C. In the remaining tanks, mortalities were daily recorded (Supplementary Figure S1), clinically and molecularly confirmed as a result of SRS. All animal procedures were carried out under the guidelines approved by the Ethics Committee of University of Concepción. were used as baseline for gene expression comparison. RNA Isolation and Sequencing Strategy RNA Isolation and Sequencing Strategy Infected tissues stored at −80◦C in RNA later solution were thawed at room temperature and total RNA (host and pathogen) was isolated from 10 different individuals using the TRIzol reagent kit (Thermo Fisher Scientific) according to manufactures instructions. RNA integrity was verified using the R6K screen tape 2200 on the TapeStation (Agilent Technologies, United States) platform. Thus, isolated RNAs with RNA Integrity Numbers (RIN) above 8 were considered for further analysis. Based on RNA quality, 3 different pools of RNA were prepared from 3 distinct individuals for each tissue and time (biological replicates). RNA pools were precipitated in absolute ethanol and shipped in dry ice to Macrogen Inc. (Korea). Here, two Ribo-Zero rRNA Removal Kit (Illumina, San Diego, CA, United States) were used to remove both bacterial and host rRNAs. Remaining RNA containing both P. salmonis and S. salar transcripts were used to prepare high-throughput sequencing libraries using the TrueSeq RNA sample preparation kit (Illumina, San Diego, CA, United States). Each library was sequenced on a HiSeq platform at 100 bp paired-end reads (Macrogen, Korea). All sequencing data will be available under the SRA accession number SUB4576220. Sequencing statistics for each RNA-seq data are presented in Supplementary Table S1. Molecular annotation of the differentially expressed transcripts for both P. salmonis and S. salar was carried out to identify the most representative biological processes. For this purpose, the Gene Ontology (GO) annotation was conducted through the BLAST2GO software V 4.1.9 (Conesa et al., 2005) and the enrichment analysis was performed using as reference the genomes of P. salmonis and S. salar. Further, resulting GO enrichment analysis was visualized in REVIGO platform (Supek et al., 2011). Finally, KEGG pathway annotation analysis was also conducted using the KEGG automatic annotation server (Moriya et al., 2007) through the bidirectional best-hit assignment method. Furthermore, RT-qPCR were used to validate sequencing results. To do this, 10 genes from the bacteria and 10 genes from the fish were randomly selected and used to RT-qPCR primer design (Supplementary Table S2). After primer validation, each RT-qPCR was conducted in a thermocycler StepOne plus (Applied Biosystems, United States) using the Maxima SYBR Green/ROX kit according to manufactures instructions. Amplification cycles were used as following 95◦C for 10 min, 40 cycles at 95◦C for 30 s, 60◦C for 30 s, and 72◦C for 30 s. RNA Isolation and Sequencing Strategy All qPCRs were carried on five biological and three technical replicates and expression values were estimated through the 21 Ct method using 16s and elongation factor 1a as normalizer genes for P. salmonis and S. salar, respectively. Significant differences between 7 and 14 dpi regarding 3 dpi were estimated with the Student’s t-test (p < 0.05). A comparison between fold-changes obtained through RT-qPCR and RNA-seq evidence a r2 value above 0.8, evidencing a high correlation between the fold changes obtained by RT-qPCR and RNA-seq (Supplementary Figure S2). Individual fold changes were included as Supplementary Figure S3. Dual RNA-Seq and Differential Expression Analysis Raw sequencing reads were filtered by quality and adapter/index were identified and removed from remaining reads using CLC Genomics Workbench (V10, CLC Bio, Denmark). In order to discriminate pathogen and host transcriptomes, cleaned reads were mapped against the last available version of the Atlantic salmon (S. salar)1 and against P. salmonis available genomes2. Mapping parameters included a mismatch cost of 2, insertion/deletion cost of 3 and a similarity/length fraction of 0.8. Effectively mapped reads against both genomes were separated in different files and used for further RNA-Seq analysis. RNA-Seq analysis was conducted using CLC Genomics Workbench (V10, CLC Bio, Denmark). Previously discriminated reads from host and pathogen were used to perform RNA-Seq analysis using all coding sequences annotated in the Atlantic salmon and P. salmonis genomes. For RNA-Seq analyses, similarity/length fraction was set as 0.9 in order to minimize the probability to include misassigned reads for each species. Expression values were estimated as transcripts per million (TPM) and normalized by totals per million read. Expression values obtained at 3 dpi Experimental Design We decided to use this dataset as reference because we needed transcriptomic data that contained reads from the pathogen to compare, since pathogenic reads in any type of control would not be present. Further, statistical differences were identified through a Baggerly’s test adjusting p-values through a false discovery rate (FDR) correction. Genes with a fold change > 4 and FDR p-values < 0.01 were considered as differentially expressed. 1https://www.ncbi.nlm.nih.gov/assembly/GCF_000233375.1/ 2https://www.ncbi.nlm.nih.gov/genome/genomes/11769 3https://www.ncbi.nlm.nih.gov/genome/genomes/511 4https://www.ncbi.nlm.nih.gov/genome/genomes/540 Exploring the Amino Acid Metabolism of P. salmonis Dual RNA-Seq analysis revealed a large number of genes differentially expressed associated with amino acid metabolism during the infection process. Due to this, we further explored the importance of amino acids in P. salmonis metabolism. First, a genome-scale comparison was conducted between P. salmonis, a second salmonid pathogen such as Aeromonas salmonicida and a closely related bacterium as Francisella tularensis. For this purpose, coding genes were obtained from NCBI for P. salmonis (see text footnote 2), F. tularensis3 and A. salmonicida4 3https://www.ncbi.nlm.nih.gov/genome/genomes/511 4https://www.ncbi.nlm.nih.gov/genome/genomes/540 November 2018 | Volume 9 | Article 2877 Frontiers in Microbiology | www.frontiersin.org 3 Dual RNA-Seq of P. salmonis Infecting S. salar Valenzuela-Miranda and Gallardo-Escárate FIGURE 1 | (A) Global transcriptome analysis of Piscirickettsia salmonis (blue) and S. salar (red) at 3, 7, and 14 days post-infection (dpi) in spleen and head kidney tissues. Expression values were estimated as transcripts per million reads (TPM) and Log2 transformed for heat map clustering. (B) Differentially expressed genes in spleen and head kidney at 7 and 14 dpi using as control the expression values at 3 dpi. Three days post-infection were used as baseline gene expression since no bacterial reads would be present in any type of control group. FIGURE 1 | (A) Global transcriptome analysis of Piscirickettsia salmonis (blue) and S. salar (red) at 3, 7, and 14 days post-infection (dpi) in spleen and head kidney tissues. Expression values were estimated as transcripts per million reads (TPM) and Log2 transformed for heat map clustering. (B) Differentially expressed genes in spleen and head kidney at 7 and 14 dpi using as control the expression values at 3 dpi. Three days post-infection were used as baseline gene expression since no bacterial reads would be present in any type of control group. material for the growth of P. salmonis in CM medium. When the exponential phase was reached, 300 µL from the liquid culture was used to inoculate 2.7 ml of liquid culture containing the different experimental mediums. All cultures were carried on triplicates and maintained at 20◦C with a constant agitation of 100 rpm. Bacterial growth was daily based monitored through the change in the optical density at an absorbance of 600 nm. A multiple t-test was carried out to identify statistically significant differences (p < 0.01) between treatments. genomes. RESULTS Exploring Host and Pathogen Transcriptome During Pathogenesis Dual RNA-Seq analysis evidenced the modulation of P. salmonis and S. salar transcriptomes during the infection. This modulation is represented in two heat maps, one for the fish host (red) and another one for the pathogen (blue), where different clusters Exploring the Amino Acid Metabolism of P. salmonis All coding sequences were annotated through KAAS annotation server as described above, focusing our attention in Histidine metabolism (00340), valine, leucine and isoleucine degradation/biosynthesis (00280 and 00290), Arginine and proline metabolism (00330), Lysine biosynthesis/degradation (00300 and 00310), Cysteine and methionine metabolism (00270), Glycine, serine and threonine metabolism (00260), Phenylalanine, tyrosine and tryptophan biosynthesis (00400) and Alanine, aspartate and glutamate metabolism (00250). Furthermore, liquid cultures of P. salmonis were conducted considering different experimental culture media with distinct amino acid composition. A basal medium (BM) was prepared with Eugon (30.4 g/l) supplemented with FeCl3 (2 mM), a complete medium (CM) prepared with Eugon (30.4 g/l) supplemented with FeCl3 (2 mM) and Casamino acid (1%) and experimental cultures medias were prepared with BM + 1% of the desired amino acid (Valine, leucine, and Isoleucine). A bacterial inoculum previously obtained from CHSE-214 cells infected with P. salmonis at 90% of lysis was used as starting Frontiers in Microbiology | www.frontiersin.org Exploring Host and Pathogen Transcriptome During Pathogenesis Dual RNA-Seq analysis evidenced the modulation of P. salmonis and S. salar transcriptomes during the infection. This modulation is represented in two heat maps, one for the fish host (red) and another one for the pathogen (blue), where different clusters November 2018 | Volume 9 | Article 2877 Frontiers in Microbiology | www.frontiersin.org 4 Dual RNA-Seq of P. salmonis Infecting S. salar Valenzuela-Miranda and Gallardo-Escárate FIGURE 2 | Venn diagram showing the number of exclusive and shared genes in the transcriptome of P. salmonis during the infection in spleen (blue) and head kidney (red) tissues of Atlantic salar. The heat maps show a subset of exclusive and shared genes expressed by P. salmonis in both tissues. FIGURE 2 | Venn diagram showing the number of exclusive and shared genes in the transcriptome of P. salmonis during the infection in spleen (blue) and head kidney (red) tissues of Atlantic salar. The heat maps show a subset of exclusive and shared genes expressed by P. salmonis in both tissues. the genes exclusively regulated in head kidney included a MATE efflux family protein, DNA repair protein RecN, chaperone protein HtpG and membrane proteins among others (Figure 2). Among shared genes, different Protein phosphatase 1, ribosomal protein, chaperones and Asn/Gln aminotransferase subunits were also found (Figure 2). The complete list of differentially expressed genes for the Atlantic salmon and P. salmonis is included as Supplementary Table S3. of expression profiles were identified (Figure 1A). Regarding S. salar transcriptome, 771 and 829 genes were differentially expressed in spleen at 7 and 14 dpi, respectively (Figure 1B). Meanwhile, 412 and 467 genes were differentially modulated in the head kidney at the same time-points (Figure 1B). On the other hand, 68 and 79 P. salmonis genes were differentially expressed in the spleen at 7 and 14 days, respectively, while 14 and 44 were identified in the head kidney (Figure 1B). Thus, the number of bacterial genes differentially expressed were increased together with the course of the infection. Since transcriptional responses for the host have been previously reported, a special focus was placed on bacterial gene expression. Herein, a Venn diagram analysis revealed that 31 P. salmonis genes were differentially regulated in both spleen and head kidney, while 101 and 15 transcripts were exclusively regulated in spleen and head kidney, respectively. Exploring Host and Pathogen Transcriptome During Pathogenesis Genes exclusively regulated in spleen included a ferritin-like domain protein, genes associated with the type IV secretion system (VirB9, IcmL, and IcmW) and several outer membrane proteins (Figure 2). On the other hand, Frontiers in Microbiology | www.frontiersin.org Amino Acid Metabolism: A Common Response Between P. salmonis and S. salar A functional annotation of the different differentially expressed genes for both S. salar and P. salmonis was conducted in order to identify key molecular pathways regulated during the infective process. GO enrichment analysis evidenced that a large percent of differentially expressed genes in P. salmonis belonged to biological processes related with the metabolism of November 2018 | Volume 9 | Article 2877 Frontiers in Microbiology | www.frontiersin.org 5 Dual RNA-Seq of P. salmonis Infecting S. salar Valenzuela-Miranda and Gallardo-Escárate FIGURE 3 | Gene ontology annotation (A) and KEGG pathway annotation (B) of the differentially expressed genes in Salmo salar and P. salmonis during the infection. The size of each circle represents the frequency of the GO term in the underlying GO database (larger circles represent more general terms) and the color represents the number of genes in each term (value). Both host and pathogen displayed a large number of genes associated to amino acid biosynthesis and degradation. FIGURE 3 | Gene ontology annotation (A) and KEGG pathway annotation (B) of the differentially expressed genes in Salmo salar and P. salmonis during the infection. The size of each circle represents the frequency of the GO term in the underlying GO database (larger circles represent more general terms) and the color represents the number of genes in each term (value). Both host and pathogen displayed a large number of genes associated to amino acid biosynthesis and degradation. signaling pathways (Supplementary Table S4), but also with key metabolic pathways, including the “biosynthesis of amino acids” (Figure 3B). Overall, the results evidenced that although the metabolism of amino acids was not the predominant transcriptomic response in the host, both P. salmonis and S. salar displayed a large number of genes involved with biosynthesis and degradation of amino acids. Due to this common response, we further investigate the role of amino acids in P. salmonis metabolism. proteins and nitrogen compounds, such as the terms “protein metabolism,” “cellular protein metabolism” and “cellular nitrogen compound biosynthesis” among others (Figure 3A). On the other hand, a more complex transcriptomic response was found in Atlantic salmon. Here, multiple biological processes were represented, such as organic acid metabolic process, oxidation-reduction process, response to external stimulus, chemotaxis among others (Supplementary Table S2). However, terms related to the metabolism of amino acids was also represented within differentially expressed transcripts, such as the “cellular amino acid metabolism” (Figure 3A). Amino Acid Metabolism: A Common Response Between P. salmonis and S. salar Enrichment of genes associated with protein metabolism was also found through KEGG annotation. Furthermore, one of the most represented pathways among differentially regulated genes in P. salmonis transcriptome included different metabolic pathways, among them, the “biosynthesis and degradation of amino acids” (Figure 3B). Regarding host transcriptome, the response of the Atlantic salmon was associated not just associated with endocytosis, cytokine-cytokine receptor interaction, apoptosis, phagosome and Nod-like receptor Frontiers in Microbiology | www.frontiersin.org DISCUSSION involved in biosynthesis/degradation of amino acids (Figure 4). However, a significant lack of genes related with valine, leucine, and isoleucine metabolism was found in P. salmonis compared with F. tularensis and A. salmonicida, where over 60% of all possible genes were found (Figure 4A). However, a deeper look into this metabolic pathway evidenced that although P. salmonis lacks the majority of the genetic background for the biosynthesis of this amino acids, it was possible to found the gene that encodes for the primary degradation of valine, leucine, and isoleucine (Figure 4B). These results suggest that the bacterium is not able to biosynthesize these amino acids and therefore a metabolic dependency of P. salmonis on environmental host amino acid availability can be expected. To further explore the importance of amino acid availability to the bacteria, P. salmonis was growth in different liquid culture mediums with different amino acidic availability. A control medium (CM) fully supplemented with amino acids, a basal medium (BM) with no supplementation of amino acids and basal mediums supplemented with 1% of either valine (BM + V), leucine (BM + I) or isoleucine (BM + L) were used as experimental mediums. The results evidence that the bacteria are not able to grow when no amino acid is supplemented. However, when BM is supplemented with either valine, leucine or isoleucine, the growth kinetics of P. salmonis resembles the one observed in a fully amino acidic supplemented condition (Figure 5). involved in biosynthesis/degradation of amino acids (Figure 4). However, a significant lack of genes related with valine, leucine, and isoleucine metabolism was found in P. salmonis compared with F. tularensis and A. salmonicida, where over 60% of all possible genes were found (Figure 4A). However, a deeper look into this metabolic pathway evidenced that although P. salmonis lacks the majority of the genetic background for the biosynthesis of this amino acids, it was possible to found the gene that encodes for the primary degradation of valine, leucine, and isoleucine (Figure 4B). These results suggest that the bacterium is not able to biosynthesize these amino acids and therefore a metabolic dependency of P. salmonis on environmental host amino acid availability can be expected. To further explore the importance of amino acid availability to the bacteria, P. salmonis was growth in different liquid culture mediums with different amino acidic availability. Role of Amino Acids in P. salmonis Metabolism To explore the importance of amino acids in P. salmonis metabolism, a genome-scale comparison was used to identify the presence/absence of genes directly involved in the degradation/biosynthesis of different bacterial pathogens. Thus, P. salmonis genome was compared with F. tularensis and A. salmonicida available genomes. Results showed that all three pathogens dispose of a similar genetic background of genes November 2018 | Volume 9 | Article 2877 Frontiers in Microbiology | www.frontiersin.org 6 Dual RNA-Seq of P. salmonis Infecting S. salar Valenzuela-Miranda and Gallardo-Escárate FIGURE 4 | (A) Genomic-wide comparison of genes involved in the biosynthesis and degradation of amino acid in P. salmonis, a close related bacterium (F. tularensis) and another fish Gram negative bacterium (A. salmonicida). Bars represent the percentage of genes identified for each pathogen underlying all the possible genes for the pathway in KEGG pathway database. (B) Subset of the biosynthesis and degradation pathway for valine, leucine, and isoleucine in P. salmonis, F. tularensis, and A. salmonicida. Circles represent intermediate molecules and arrows the genes catalyzing each reaction. Thus, a green arrow represents a gene that was found in the genome of each pathogen and gray ones for those absent. Thus, P. salmonis evidenced a smaller number of genes involved in valine, leucine, and isoleucine biosynthesis/degradation. FIGURE 4 | (A) Genomic-wide comparison of genes involved in the biosynthesis and degradation of amino acid in P. salmonis, a close related bacterium (F. tularensis) and another fish Gram negative bacterium (A. salmonicida). Bars represent the percentage of genes identified for each pathogen underlying all the possible genes for the pathway in KEGG pathway database. (B) Subset of the biosynthesis and degradation pathway for valine, leucine, and isoleucine in P. salmonis, F. tularensis, and A. salmonicida. Circles represent intermediate molecules and arrows the genes catalyzing each reaction. Thus, a green arrow represents a gene that was found in the genome of each pathogen and gray ones for those absent. Thus, P. salmonis evidenced a smaller number of genes involved in valine, leucine, and isoleucine biosynthesis/degradation. DISCUSSION th t i ti l d l ti f th of several members of the type IV secretion system, including VirB9, IcmL, and IcmW. The type IV secretion system it has been described as a conserved mechanism for the delivery of virulent factors from host to pathogen (Thanassi and Hultgren, 2000). This system has been previously described in P. salmonis (Gomez et al., 2013) and even the directed mutagenesis of this locus has resulted in the attenuation of the pathogenesis of P. salmonis (Mancilla et al., 2018). On the other hand, the repertory of genes displayed by the Atlantic salmon in response to infection was classified into different molecular pathways. These processes included endocytosis, cytokine-cytokine receptor interaction, apoptosis, phagosome and Nod-like receptor signaling pathways, which has been previously described as key responses triggered during the infection of P. salmonis in S. salar tissues (Valenzuela-Miranda and Gallardo-Escarate, 2016). However, beyond the canonical pathogenic genes commonly associated with bacterial pathogenesis and the Atlantic salmon immunity (Valenzuela-Miranda and Gallardo-Escarate, 2016; Tarifeno-Saldivia et al., 2017), a common response associated with protein metabolism and particularly the biosynthesis/degradation of amino acids was present in both S. salar and P. salmonis transcriptomic response during the infection process. Due to this, a genome-scale comparison was performed in order to evidence the genetic background of genes involved in biosynthesis degradation of amino acids in P. salmonis, a close related bacterium F. tularensis and another salmonid bacterial pathogen A. salmonicida. The genomic background has been previously used to predict essential and non-essential amino acids in different pathogens (Meibom and Charbit, 2010). Based on our results, we found a lack of biosynthetic genes associated with the metabolism of valine, leucine, and isoleucine for P. salmonis when compared with F. tularensis and A. salmonicida genomes. Therefore, the availability of these amino acids for P. salmonis might rely upon the presence of these resources in the host intracellular environment. During infection, intracellular pathogens must overcome different adverse condition, such as the entrance to host cells, host immune response, free radicals and also nutrient deprivation. Although host cytosol was previously considered as an abundant source of nutrients for invading pathogens (Ray et al., 2009), recent evidence suggests that hosts can reduce the intracellular availability of certain nutrients as a protective response against the invading pathogens (Abu Kwaik and Bumann, 2013; Barel and Charbit, 2013). DISCUSSION A control medium (CM) fully supplemented with amino acids, a basal medium (BM) with no supplementation of amino acids and basal mediums supplemented with 1% of either valine (BM + V), leucine (BM + I) or isoleucine (BM + L) were used as experimental mediums. The results evidence that the bacteria are not able to grow when no amino acid is supplemented. However, when BM is supplemented with either valine, leucine or isoleucine, the growth kinetics of P. salmonis resembles the one observed in a fully amino acidic supplemented condition (Figure 5). Dual RNA-Seq has emerged as a promising approach to elucidate host–pathogen interaction. Although this approach was previously limited to pathogens that resembles host transcripts (Westermann et al., 2017), the development of high-throughput sequencing technologies has allowed to expand this approach to bacterial infections. In this context, we applied a dual RNA-Seq approach to explore novel means of interaction between the intracellular bacterium P. salmonis and its main host the Atlantic salmon (S. salar). In addition to being the main threat to Chilean salmonid aquaculture (Rozas and Enriquez, 2014), the intracellular nature of this pathogen makes it an interesting model to study host immune evasion strategies and intracellular survival mechanisms employed by intracellular pathogens. The dual RNA-Seq analysis revealed the presence of different bacterial genes among the spleen and head kidney transcriptome. Thus, the spleen showed the largest number of bacterial genes regarding the ones found in head kidney data. This can be attributable due to when IP injection is used as infection method in previous IP challenges with P. salmonis, the spleen is one of the first tissues to be infected, followed by head kidney (Valenzuela-Miranda and Gallardo-Escarate, 2016). Therefore, the differences between November 2018 | Volume 9 | Article 2877 Frontiers in Microbiology | www.frontiersin.org 7 Dual RNA-Seq of P. salmonis Infecting S. salar Valenzuela-Miranda and Gallardo-Escárate FIGURE 5 | Growth kinetics of P. salmonis in liquid culture media supplemented with different amino acids. Bacteria was growth in a control medium (CM), a basal medium without amino acids (BM) and in basal mediu supplemented with valine (BM + V), leucine (BM + L), and isoleucine (BM + I) amino acids at 1%. ∗Represents statistically significant differences (p < 0.01 between the supplemented medium (Val, Leu, or Ile) regarding control group (no amino acids). Frontiers in Microbiology | www.frontiersin.org DISCUSSION This deprivation results in a struggle between host and pathogen for the limited nutrient availability, which commonly known as nutritional immunity (Hood and Skaar, 2012). Thus, it has been suggested that part of the immune response of the Atlantic salmon to P. salmonis infection relies on the nutritional immunity. This has been exclusively explored due to the struggle for iron availability. From P. salmonis perspective, it has been suggested the importance of a siderophore-based mechanism to capture iron from different host sources (Calquin et al., 2018). On the other hand, the infection of P. salmonis induces a FIGURE 5 | Growth kinetics of P. salmonis in liquid culture media supplemented with different amino acids. Bacteria was growth in a control medium (CM), a basal medium without amino acids (BM) and in basal medium supplemented with valine (BM + V), leucine (BM + L), and isoleucine (BM + I) amino acids at 1%. ∗Represents statistically significant differences (p < 0.01) between the supplemented medium (Val, Leu, or Ile) regarding control group (no amino acids). FIGURE 5 | Growth kinetics of P. salmonis in liquid culture media supplemented with different amino acids. Bacteria was growth in a control medium (CM), a basal medium without amino acids (BM) and in basal medium supplemented with valine (BM + V), leucine (BM + L), and isoleucine (BM + I) amino acids at 1%. ∗Represents statistically significant differences (p < 0.01) between the supplemented medium (Val, Leu, or Ile) regarding control group (no amino acids). the transcriptional modulation of pathogen genes among this tissue could be as a result of different infection stages rather than a tissue-specific transcriptomic response of the pathogen. Nevertheless, different classical pathogenic related genes were identified in transcriptomic data. Such as the case November 2018 | Volume 9 | Article 2877 Frontiers in Microbiology | www.frontiersin.org 8 Dual RNA-Seq of P. salmonis Infecting S. salar Valenzuela-Miranda and Gallardo-Escárate strong transcriptomic modulation of genes involved in iron availability in S. salar (Pulgar et al., 2015; Valenzuela- Miranda and Gallardo-Escarate, 2016). In this context, our results evidence that both host and pathogen display a large number of genes involved in the biosynthesis/degradation of amino acids. Considering the lack of biosynthetic pathways in leucine, valine and isoleucine in P. DISCUSSION salmonis and that these same amino acids are defined as essential amino acids for salmonids (Helland et al., 2010), we suggest that this transcriptional modulation can be reflecting an amino acid-based nutritional immunity triggered by S. salar to overcome P. salmonis infection. In turn, P. salmonis displayed a transcriptional modulation of different genes associated with amino acid metabolism to deal with host response. acid sources could become an advantage in a resource- limited scenario. This metabolic plasticity has been reported in other intracellular pathogens like F. tularensis, where the intracellular survival of this bacteria relies on their availability to exploit multiple host amino acids (Meibom and Charbit, 2010; Barel et al., 2015). Based in our results, and considering the recently proposed metabolic models for P. salmonis (Cortes et al., 2017; Fuentealba et al., 2017), we can hypothesize that this bacteria is capable to use different amino acids as a carbon an energy resource. This strategy has been adopted by others intracellular bacterium, where this capability has been described as a crucial factor for virulence development (Eisenreich et al., 2010; Meibom and Charbit, 2010; Barel et al., 2015). In this scenario, the implications of a metabolic plasticity in P. salmonis and its link to virulence of different bacterial strains must be further explored. Intracellular pathogens have developed different strategies to overcome amino acids starvation triggered by the host during infection. Some of these adaptations include the growth arrest and differentiation, an amino acid self-sufficiency and to exploit host machinery to obtain amino acids form host cell (Zhang and Rubin, 2013). Based on our results and considering the recent reconstruction of metabolic models for the bacteria (Cortes et al., 2017), the self-sufficiency strategy for amino acids in the P. salmonis can be rejected. Regarding growth arrest and differentiation, it has been reported that during an amino acid restricted scenario C. trachomatis morphologically changes into an aberrant form that is unable to grow but protects them from a nutrient restricted environment (Leonhardt et al., 2007). However, the addition of tryptophan or isoleucine can restore these aberrant forms and reactivate bacterial growth (Hatch, 1975; Ibana et al., 2011). Previously, it has been reported the existence of morphological small variants of P. salmonis, which were suggested as a survival mechanism employed by the bacteria to overcome adverse scenarios (Veronica Rojas et al., 2008). FUNDING This work was supported by the CONICYT-PCHA/Doctorado Nacional (Grant 2015-21150728), FONDECYT (1180867), and FONDAP (1510027). ACKNOWLEDGMENTS The authors are grateful for the support provided by the Ph.D. Program in Renewable Resource Management of the University of Concepción, Chile. DISCUSSION However, the role of these variants during an amino acid restricted scenario and its relation with virulence remains unexplored. On the other hand, pathogens like Legionella pneumophila have devolved mechanism that grants the access to host nutrients by promoting the expression of host amino acid transporters and taking advantage of proteasomes of infected cells to generate free amino acids for bacterial growth (Wieland et al., 2005; Price et al., 2011). In this context, it has been suggested that one of the mechanisms employed by P. salmonis to evade immune response can be related with the regulation of host transcriptional response through non-coding RNAs (Valenzuela-Miranda and Gallardo-Escarate, 2016; Valenzuela- Miranda et al., 2017), therefore, the idea that P. salmonis is able to hijack host machinery to obtain amino acids should also be explored. Overall, our results showed how a dual RNA-Seq approach can lead us to the understanding of novel means of interaction between host and pathogens. However, the importance of an amino acid-based nutritional immunity of S. salar in response to P. salmonis infection must be further investigated. This information will not just lead us to the development of novel treatments for the pathogen, but also to the understanding of the pathogenesis process from a different perspective, beyond canonical immunological mechanisms. AUTHOR CONTRIBUTIONS DV-M and CG-E conceived the study and drafted the manuscript. DV-M performed the experiments and analyzed the data under CG-E extensive supervision. Frontiers in Microbiology | www.frontiersin.org REFERENCES Mancilla, M., Saavedra, J., Grandon, M., Tapia, E., Navas, E., Grothusen, H., et al. (2018). The mutagenesis of a type IV secretion system locus of Piscirickettsia salmonis leads to the attenuation of the pathogen in atlantic salmon, Salmo salar. J. Fish Dis. 41, 625–634. doi: 10.1111/jfd.12762 Abu Kwaik, Y., and Bumann, D. (2013). Microbial quest for food in vivo: ‘nutritional virulence’ as an emerging paradigm. Cell. Microbiol. 15, 882–890. doi: 10.1111/cmi.12138 j Mauel, M. J., and Miller, D. L. (2002). Piscirickettsiosis and piscirickettsiosis-like infections in fish: a review. Vet. Microbiol. 87, 279–289. Baddal, B., Muzzi, A., Censini, S., Calogero, R. A., Torricelli, G., Guidotti, S., et al. (2016). Erratum for baddal et al., dual RNA-seq of nontypeable Haemophilus influenzae and host cell transcriptomes reveals novel insights into host-pathogen cross talk. Mbio 7:e003 73–16. Mavromatis, C. H., Bokil, N. J., Totsika, M., Kakkanat, A., Schaale, K., Cannistraci, C. V., et al. (2015). The co-transcriptome of uropathogenic Escherichia coli-infected mouse macrophages reveals new insights into host-pathogen interactions. Cell. Microbiol. 17, 730–746. doi: 10.1111/cmi. 12397 reveals novel insights into host-pathogen cross talk. Mbio 7:e003 73–16. Barel, M., and Charbit, A. (2013). Francisella tularensis intracellular survival: to eat or to die. Microb. Infect. 15, 989–997. McCarthy, U. M., Bron, J. E., Brown, L., Pourahmad, F., Bricknell, I. R., Thompson, K. D., et al. (2008). Survival and replication of Piscirickettsia salmonis in rainbow trout head kidney macrophages. Fish Shellfish Immun. 25, 477–484. doi: 10.1016/j.fsi.2008.07.005 Barel, M., Ramond, E., Gesbert, G., and Charbit, A. (2015). The complex amino acid diet of francisella in infected macrophages. Front. Cell. Infect. Microbiol. 5:9. doi: 10.3389/fcimb.2015.00009 Bravo, S., and Midtlyng, P. J. (2007). The use of fish vaccines in the chilean salmon industry 1999-2003. Aquaculture 270, 36–42. Meibom, K. L., and Charbit, A. (2010). Francisella tularensis metabolism and its relation to virulence. Front. Microbiol. 1:140. doi: 10.3389/fmicb.2010.00140 Calquin, P., Ruiz, P., Oliver, C., Sanchez, P., Haro, R., Oliva, H., et al. (2018). Physiological evidence that Piscirickettsia salmonis produces siderophores and uses iron from different sources. J. Fish Dis. 41, 553–558. Moriya, Y., Itoh, M., Okuda, S., Yoshizawa, A. C., and Kanehisa, M. (2007). KAAS: an automatic genome annotation and pathway reconstruction server. Nucleic Acids Res. 35, W182–W185. Pittman, K. J., Aliota, M. T., and Knoll, L. J. (2014). Dual transcriptional profiling of mice and Toxoplasma gondii during acute and chronic infection. BMC Genomics 15:806. doi: 10.1186/1471-2164-15-806 Choi, Y. REFERENCES Microarray analyses identify molecular biomarkers of atlantic salmon macrophage and hematopoietic kidney response to Piscirickettsia salmonis infection. Physiol. Genomics 20, 21–35. Hatch, T. P. (1975). Competition between Chlamydia psittaci and L cells for host isoleucine pools: a limiting factor in chlamydial multiplication. Infect. Immun. 12, 211–220. to Piscirickettsia salmonis infection. Physiol. Genomics 20, 21–35. Helland, S. J., Hatlen, B., and Grisdale-Helland, B. (2010). Energy, protein and amino acid requirements for maintenance and efficiency of utilization for growth of atlantic salmon post-smolts determined using increasing ration levels. Aquaculture 305, 150–158. Rozas, M., and Enriquez, R. (2014). Piscirickettsiosis and Piscirickettsia salmonis in fish: a review. J. Fish Dis. 37, 163–188. doi: 10.1111/jfd.12211 Smith, P. A., Contreras, J. R., Larenas, J. J., Aguillon, J. C., Garces, L. H., Perez, B., et al. (1997). Immunization with bacterial antigens: piscirickettsiosis. Dev. Biol. 90, 161–166. Hood, M. I., and Skaar, E. P. (2012). Nutritional immunity: transition metals at the pathogen-host interface. Nat. Rev. Microbiol. 10, 525–537. doi: 10.1038/ nrmicro2836 Steeb, B., Claudi, B., Burton, N. A., Tienz, P., Schmidt, A., Farhan, H., et al. (2013). Parallel exploitation of diverse host nutrients enhances Salmonella virulence. PLoS Pathog. 9:e1003301. doi: 10.1371/journal.ppat.1003301 Humphrys, M. S., Creasy, T., Sun, Y., Shetty, A. C., Chibucos, M. C., Drabek, E. F., et al. (2013). Simultaneous transcriptional profiling of bacteria and their host cells. PLoS One 8:e80597. doi: 10.1371/journal.pone.008 0597 Strong, M. J., Xu, G., Coco, J., Baribault, C., Vinay, D. S., Lacey, M. R., et al. (2013). Differences in gastric carcinoma microenvironment stratify according to EBV infection intensity: implications for possible immune adjuvant therapy. PLoS Pathog. 9:e1003341. doi: 10.1371/journal.ppat.1003341 Ibana, J. A., Belland, R. J., Zea, A. H., Schust, D. J., Nagamatsu, T., AbdelRahman, Y. M., et al. (2011). Inhibition of indoleamine 2,3-dioxygenase activity by levo- 1-methyl tryptophan blocks gamma interferon-induced Chlamydia trachomatis persistence in human epithelial cells. Infect. Immun. 79, 4425–4437. doi: 10. 1128/IAI.05659-11 Pathog. 9:e1003341. doi: 10.1371/journal.ppat.1003341 Supek, F., Bosnjak, M., Skunca, N., and Smuc, T. (2011). REVIGO summarizes and visualizes long lists of gene ontology terms. PLoS One 6:e21800. doi: 10.1371/ journal.pone.0021800 Tacchi, L., Bron, J. E., Taggart, J. B., Secombes, C. J., Bickerdike, R., Adler, M. A., et al. (2011). Multiple tissue transcriptomic responses to Piscirickettsia salmonis in atlantic salmon (Salmo salar). Physiol. Genomics 43, 1241–1254. doi: 10.1152/ physiolgenomics.00086.2011 Leonhardt, R. M., Lee, S. J., Kavathas, P. B., and Cresswell, P. (2007). REFERENCES J., Aliota, M. T., Mayhew, G. F., Erickson, S. M., and Christensen, B. M. (2014). Dual RNA-seq of parasite and host reveals gene expression dynamics during filarial worm-mosquito interactions. PLoS Negl. Trop. Dis. 8:e2905. doi: 10.1371/journal.pntd.0002905 Price, C. T., Al-Quadan, T., Santic, M., Rosenshine, I., and Abu Kwaik, Y. (2011). Host proteasomal degradation generates amino acids essential for intracellular bacterial growth. Science 334, 1553–1557. doi: 10.1126/science.1212868 Conesa, A., Gotz, S., Garcia-Gomez, J. M., Terol, J., Talon, M., and Robles, M. (2005). Blast2GO: a universal tool for annotation, visualization and analysis in functional genomics research. Bioinformatics. 21, 3674–3676. Pulgar, R., Hodar, C., Travisany, D., Zuniga, A., Dominguez, C., Maass, A., et al. (2015). Transcriptional response of atlantic salmon families to Piscirickettsia salmonis infection highlights the relevance of the iron-deprivation defence system. BMC Genomics 16:495. doi: 10.1186/s12864-015-1716-9 Cortes, M. P., Mendoza, S. N., Travisany, D., Gaete, A., Siegel, A., Cambiazo, V., et al. (2017). Analysis of Piscirickettsia salmonis metabolism using genome-scale reconstruction, modeling, and testing. Front. Microbiol. 8:2462. doi: 10.3389/ fmicb.2017.02462 Rajas, V., Galanti, N., Bols, N. C., and Marshall, S. H. (2009). Productive Infection of Piscirickettsia salmonis in macrophages and monocyte-like cells from rainbow trout, a possible survival strategy. J. Cell. Biochem. 108, 631–637. doi: 10.1002/jcb.22295 Eisenreich, W., Dandekar, T., Heesemann, J., and Goebel, W. (2010). Carbon metabolism of intracellular bacterial pathogens and possible links to virulence. Nat. Rev. Microbiol. 8, 401–412. doi: 10.1038/nrmicro2351 Ramirez, R., Gomez, F. A., and Marshall, S. H. (2015). The infection process of Piscirickettsia salmonis in fish macrophages is dependent upon interaction with host-cell clathrin and actin. FEMS Microbiol. Lett. 362, 1–8. doi: 10.1093/femsle/ fnu012 Fuentealba, P., Aros, C., Latorre, Y., Martinez, I., Marshall, S., Ferrer, P., et al. (2017). Genome-scale metabolic reconstruction for the insidious bacterium in aquaculture Piscirickettsia salmonis. Bioresour. Technol. 223, 105–114. doi: 10.1016/j.biortech.2016.10.024 Ray, K., Marteyn, B., Sansonetti, P. J., and Tang, C. M. (2009). Life on the inside: the intracellular lifestyle of cytosolic bacteria. Nat. Rev. Microbiol. 7, 333–340. doi: 10.1038/nrmicro2112 Gomez, F. A., Tobar, J. A., Henriquez, V., Sola, M., Altamirano, C., and Marshall, S. H. (2013). Evidence of the presence of a functional Dot/Icm type IV-B secretion system in the fish bacterial pathogen Piscirickettsia salmonis. PLoS One 8:e54934. doi: 10.1371/journal.pone.0054934 Rise, M. L., Jones, S. R., Brown, G. D., von Schalburg, K. R., Davidson, W. S., and Koop, B. F. (2004). SUPPLEMENTARY MATERIAL The importance of amino acids in pathogenic cell cycle has not only be associated as a primary resource for the biogenesis of proteins, but also as alternative sources of carbon and nitrogen (Steeb et al., 2013). Therefore, a metabolic plasticity to obtain carbon and energy from multiple amino The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fmicb. 2018.02877/full#supplementary-material November 2018 | Volume 9 | Article 2877 Frontiers in Microbiology | www.frontiersin.org 9 Dual RNA-Seq of P. salmonis Infecting S. salar Valenzuela-Miranda and Gallardo-Escárate REFERENCES Severe tryptophan starvation blocks onset of conventional persistence and reduces reactivation of Chlamydia trachomatis. Infect. Immun. 75, 5105–5117. Tarifeno-Saldivia, E., Valenzuela-Miranda, D., and Gallardo-Escarate, C. (2017). In the shadow: the emerging role of long non-coding RNAs in the immune response of atlantic salmon. Dev. Comp. Immunol. 73, 193–205. doi: 10.1016/ j.dci.2017.03.024 Machuca, A., and Martinez, V. (2016). Transcriptome analysis of the intracellular facultative pathogen Piscirickettsia salmonis: expression of putative groups of genes associated with virulence and iron metabolism. PLoS One 11:e0168855. doi: 10.1371/journal.pone.0168855 November 2018 | Volume 9 | Article 2877 Frontiers in Microbiology | www.frontiersin.org 10 Dual RNA-Seq of P. salmonis Infecting S. salar Valenzuela-Miranda and Gallardo-Escárate Thanassi, D. G., and Hultgren, S. J. (2000). Multiple pathways allow protein secretion across the bacterial outer membrane. Curr. Opin. Cell Biol. 12, 420–430. Westermann, A. J., Forstner, K. U., Amman, F., Barquist, L., Chao, Y., Schulte, L. N., et al. (2016). Dual RNA-seq unveils noncoding RNA functions in host- pathogen interactions. Nature 529, 496–501. doi: 10.1038/nature16547 Tierney, L., Linde, J., Muller, S., Brunke, S., Molina, J. C., Hube, B., et al. (2012). An interspecies regulatory network inferred from simultaneous RNA- seq of candida albicans invading innate immune cells. Front. Microbiol. 3:85. doi: 10.3389/fmicb.2012.00085 Westermann, A. J., Gorski, S. A., and Vogel, J. (2012). Dual RNA-seq of pathogen and host. Nat. Rev. Microbiol. 10, 618–630. Wieland, H., Ullrich, S., Lang, F., and Neumeister, B. (2005). Intracellular multiplication of Legionella pneumophila depends on host cell amino acid transporter SLC1A5. Mol. Microbiol. 55, 1528–1537. Valenzuela-Miranda, D., and Gallardo-Escarate, C. (2016). Novel insights into the response of atlantic salmon (Salmo salar) to Piscirickettsia salmonis: interplay of coding genes and lncRNAs during bacterial infection. Fish Shellfish Immunol. 59, 427–438. doi: 10.1016/j.fsi.2016.11.001 Zhang, Y. J., and Rubin, E. J. (2013). Feast or famine: the host-pathogen battle over amino acids. Cell Microbiol. 15, 1079–1087. doi: 10.1111/cmi.12140 Conflict of Interest Statement: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Valenzuela-Miranda, D., Valenzuela-Munoz, V., Farlora, R., and Gallardo- Escarate, C. (2017). MicroRNA-based transcriptomic responses of atlantic salmon during infection by the intracellular bacterium Piscirickettsia salmonis. Dev. Comp. Immunol. 77, 287–296. doi: 10.1016/j.dci.2017.08.016 ev. Comp. Immunol. 77, 287–296. doi: 10.1016/j.dci.2017.08.016 Copyright © 2018 Valenzuela-Miranda and Gallardo-Escárate. Frontiers in Microbiology | www.frontiersin.org November 2018 | Volume 9 | Article 2877 REFERENCES This is an open- access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Copyright © 2018 Valenzuela-Miranda and Gallardo-Escárate. This is an open- access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Veronica Rojas, M., Olivares, P. J., del Rio, R., and Marshall, S. H. (2008). Characterization of a novel and genetically different small infective variant of Piscirickettsia salmonis. Microb. Pathog. 44, 370–378. doi: 10.1016/j.micpath. 2007.10.012 Westermann, A. J., Barquist, L., and Vogel, J. (2017). Resolving host-pathogen interactions by dual RNA-seq. PLoS Pathog. 13:e1006033. doi: 10.1371/journal. ppat.1006033 November 2018 | Volume 9 | Article 2877 Frontiers in Microbiology | www.frontiersin.org 11
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https://www.nature.com/articles/cddis2013105.pdf
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Gap junctional communication promotes apoptosis in a connexin-type-dependent manner
Cell death and disease
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1Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universita¨t Mu¨nchen and Munich University Hospital, Munich, Germany; 2DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany and 3Munich Cluster for Systems Neurology (SyNergy), Munich, Germany *Corresponding author: P Kameritsch, Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universita¨t Mu¨nchen and Munich University Hospital, Marchioninistrasse 27, Mu¨nchen 81377, Germany. Tel: þ 49 89 2180 76536; Fax: þ 49 89 2180 76532; E-mail: Kameritsch@lmu.de Received 10.8.12; revised 31.1.13; accepted 21.2.13; Edited by Y Shi Keywords: gap junction; connexin; apoptosis; streptonigrin; Fas; Ca2 þ; IP3 Abbreviations: GJ, gap junction; Cx, connexin/s; NT, N-terminal part; CT, C-terminal part; SN, streptonigrin; Ca2 þ i, intracellular free calcium; FITC, fluorescein isothiocyanate; PI, propidium iodide; aa, amino acids; IP3, inositol triphosphate; a, anti Gap junctional communication promotes apoptosis in a connexin-type-dependent manner P Kameritsch*,1, N Khandoga1, U Pohl1,2,3 and K Pogoda1 Gap junctions (GJs) have been described to modulate cell death and survival. It still remains unclear whether this effect requires functional GJ channels or depends on channel-independent effects of connexins (Cx), the constituents of GJs. Therefore, we analysed the apoptotic response to streptonigrin (SN, intrinsic apoptotic pathway) or to a-Fas (extrinsic apoptotic pathway) in HeLa cells expressing Cx43 as compared with empty vector-transfected (CTL) cells. Apoptosis assessed by annexin V-fluorescein isothiocyanate/propidium iodide staining was significantly higher in HeLa-Cx43 compared with HeLa-CTL cells. Moreover, the cleavage of caspase-7 or Parp occurred earlier in HeLa-Cx43 than in HeLa-CTL cells. Comparative analysis of the effect of two further (endothelial) Cx (Cx37 and Cx40) on apoptosis revealed that apoptosis was highest in HeLa-Cx43 and lowest in HeLa-Cx37 cells, and correlated with the GJ permeability (assessed by spreading of a GJ-permeable dye and locally induced Ca2 þ signals). Pharmacologic inhibition of GJ formation in HeLa-Cx43 cells reduced apoptosis significantly. The role of GJ communication was further analysed by the expression of truncated Cx43 proteins with and without channel-forming capacity. Activation of caspases was higher in cells expressing the channel-building part (HeLa-Cx43NT-GFP) than in cells expressing the channel-incompetent C-terminal part of Cx43 (HeLa-Cx43CT-GFP) only. A hemichannel-dependent release and, hence, paracrine effect of proapoptotic signals could be excluded since the addition of a peptide (Pep)-blocking Cx43-dependent hemichannels (but not GJs) did not reduce apoptosis in HeLa-Cx43 cells. Treatment with SN resulted in a significant higher increase of the intracellular free Ca2 þ concentration in HeLa-Cx43 and HeLa-Cx43NT-GFP cells compared with HeLa-CTL or HeLa-Cx43CT-GFP cells, suggesting that Ca2 þ or a Ca2 þ-releasing agent could play a signalling role. Blocking of inositol triphosphate receptors reduced the SN-induced Ca2 þ increase as well as the increase in apoptosis. Our observations suggest that Cx43 and Cx40 but not Cx37 promote apoptosis via gap junctional transfer of pro-apoptotic signals between cells. Cell Death and Disease (2013) 4, e584; doi:10.1038/cddis.2013.105; published online 11 April 2013 Subject Category: Experimental Medicine decreased expression of bcl-2 has been described, and a suppression of Src activity was observed in Cx43-expressing malignant mesothelioma cells.14,15 Moreover, the intracellular localisation of Cx43 at the mitochondrial16–19 or nuclear20 membranes has been shown to have a role in this context. Other reports refer to a distinct role of gap junctional communication in promoting apoptosis. Citation: Cell Death and Disease (2013) 4, e584; doi:10.1038/cddis.2013.105 & 2013 Macmillan Publishers Limited All rights reserved 2041-4889/13 Citation: Cell Death and Disease (2013) 4, e584; doi:10.1038/cddis.2013.105 & 2013 Macmillan Publishers Limited All rights reserved 2041-4889/13 Results The fluorescence intensity (red fluorescence units (RFUs)), indicating activated caspases, was significantly higher in the channel-forming HeLa-Cx43-GFP (mean±S.E.M.: 21 422±1494) and HeLa-Cx43NT-GFP cells (22 546±2031) as compared with the channel-incompetent HeLa-Cx43CT-GFP cells (14 543±758; Figure 4). The Cx effect on apoptosis varies with the Cx type and correlates with gap junctional dye or calcium transfer. To elucidate the effect of other Cx proteins and their channel properties on the development of apoptosis, HeLa cells expressing either Cx37 or Cx40 or Cx43 were compared. The expression of the different Cx proteins was analysed by western blot (Figure 2a). Immunocytochemically, the cells showed the typical expression pattern with an increased localisation at cell–cell contacts (Figure 2b). Cx-deficient HeLa-CTL cells were used as controls. Apoptosis was induced with SN (1 mM, 3 h) and measured by annexin V-FITC/PI staining. The increase of apoptotic cells after stimulation with SN was lowest in HeLa-CTL cells and highest in Cx43-expressing cells (Figure 2c). The SN-induced increase in apoptotic cells was significantly higher in Cx43-expressing cells compared with HeLa-Cx37 cells. p g p To figure out whether the differences in the increase of SN-induced apoptotic cells were associated with different GJ channel permeabilities, we assessed cell coupling by inter- cellular spreading of a GJ-permeable fluorescent dye after injection of a single cell (Figure 2d). HeLa-CTL cells showed no (n stained cells, mean±S.E.M.: 0.1±0.1) and HeLa-Cx37 only little dye transfer (2±1). In contrast, cell coupling of Cx40- and Cx43-expressing HeLa cells (Cx40: 9±1; Cx43: 17±2) was significantly elevated as compared with HeLa- CTL cells. Thus, the highest number of stained neighbouring cells was observed in HeLa-Cx43 cells. In addition, we analysed the intercellular spreading of a Ca2 þ signal after mechanical stimulation of a single cell. Again, the signal spread wider in HeLa-Cx43 cells compared with HeLa-Cx37 and HeLa-CTL cells (n cells with elevated Ca2 þ; mean± S.E.M. – Cx43: 21±3; Cx37: 12±2; CTL: 0±0; Po0.05; two different cell cultures, n ¼ 10–14). Hemichannels are not involved in augmented apoptosis of Cx43-expressing cells. Gap junctional communication promotes apoptosis in a connexin-type-dependent manner For example, experi- ments performed with heavy ions21 or cytochrome C22,23 as inducers of apoptosis demonstrated cell death in untreated neighbouring cells, which points towards a role of GJs in modulating apoptosis. Not only death signals but also cell survival factors have been proposed to be transferred via GJs.24–26 However, in most cases, it has not been studied whether GJ channels or channel-independent effects were important. Thus, it remains unclear which of the two potential Cx-related pathways is quantitatively more important and whether the modulatory effect of Cx on apoptosis depends on the type of Cx expressed. It is also unclear which signals or small molecules, which are able to pass GJs, could be involved in promotion of apoptosis. A growing body of evidence shows that connexins (Cx) are able to modulate essential cellular processes such as proliferation, differentiation and migration. Likewise, survival and apoptosis have been shown to be partially Cx-dependent processes.1–3 However, it remains unclear whether Cx exert their functions in a manner which is dependent on their ability to form gap junction (GJ) channels or whether channel- independent properties of Cx play a role such as that observed in cell migration and proliferation.4–7 This question is still controversially discussed. There are a few studies suggesting that Cx, and in particular Cx43, have effects on cell death and survival by mechanisms independent of gap junctional communication. Most of these effects have been related to the potential role of hemichannels that may allow the passage of proapoptotic or survival factors from the intracel- lular to the extracellular space or vice versa.8–12 Alternatively, regulatory effects of Cx were found to play a role in pro- and antiapoptotic genes.1 DNA arrays of Cx43-null and wild-type mice indeed showed clear differences in gene expression.13 For example, in Cx43-expressing glioblastoma cells, a Gap junctions promote apoptosis P Kameritsch et al 2 2 To clarify these questions, we studied apoptosis in Cx-transfected HeLa cells with no background expression of Cx in the wild-type state. Our results show that the Cx-dependent enhancement of apoptosis requires gap junctional communica- tion and that this effect varies with the type of Cx expressed. We further investigated whether the treatment with SN has an influence on the gap junctional coupling. Dye transfer via GJs was measured in HeLa-Cx43 cells, the cell population with the highest amount of apoptosis. Results Expression of Cx43 enhances the rate of apoptosis. To examine the effect of Cx43 expression on apoptosis, we used HeLa cells stably transfected with Cx43 or Cx-deficient empty vector-transfected HeLa cells (CTL) as controls. Apoptosis was either induced by streptonigrin (SN; intrinsic pathway) or a-Fas (extrinsic receptor-stimulated pathway). Treatment with SN (1, 10 mM) or a-Fas (10, 100 ng/ml) lasted for 5 h and the rate of apoptosis was determined by annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) staining. Under both conditions, the apoptosis was signifi- cantly higher in HeLa-Cx43 cells compared with HeLa-CTL cells (Figure 1b). Likewise, treatment with SN (10 mM) resulted in a higher and earlier increase of cleavage products of Parp (cl. Parp) and caspase-7 (cl. Cas7) when Cx43 was present (Figure 1c). Similarly, stimulation with a-Fas (100ng/ml) resulted in cleaved Parp and caspase-7 already after 2h in HeLa-Cx43 cells, whereas in HeLa-CTL cells, it started only after 4h (Figure 1c). Gap junctional communication is required for enhance- ment of apoptosis. The role of GJ communications for the enhanced apoptosis was firstly investigated by using the GJ blockers meclofenamic acid (M; 100 mM) and heptanol (H, 0.25 mM). The amount of SN- or a-Fas-induced apoptotic HeLa-Cx43 cells (mean±S.E.M. – 1 mM SN: 15.5±4.7%; 100 ng/ml Fas: 24.1±3.6%) was significantly reduced under treatment with GJ blockers (1 mM SN þ MH: 7.1±0.4%; 100 ng/ml Fas þ MH: 11.8±1.1%; Figure 3). GJ blockers alone did not affect the basal rate of apoptosis (untreated cells: 6.4±0.6%; cells treated with the GJ blockers only – MH: 6.0±0.7%). To further analyse whether an intact channel function between cells was necessary for the enhanced apoptosis in Cx43-expressing cells, we compared apoptosis in HeLa cells expressing the N-terminal channel-building part of Cx43 (Cx43NT-GFP) with cells expressing the cytoplasmic C-term- inal part (CT) of Cx43 (Cx43CT-GFP), which cannot form GJs or hemichannels but exerts channel-independent functions of Cx43.5 As controls, we used HeLa cells expressing full-length Cx43 (Cx43-GFP). To determine the rate of SN-induced apoptosis in these cells, the amount of activated caspases (caspase-1, -3, -4, -5, -6, -7, -8 and -9) was measured (binding of a red fluorescent-labelled inhibitor to active caspases), as the expression of GFP interfered with the annexin V-FITC/PI assay otherwise used. Gap junctional communication promotes apoptosis in a connexin-type-dependent manner After treatment with SN for 1 or 3 h, the cells were still able to form functional GJs, although the rate of coupling decreased over time (n stained cells; mean±S.E.M. – untreated cells: 17±2; 1 mM SN for 1 h: 11±2; 1 mM SN for 3 h: 6±1; nZ7 in three different cell cultures). Results Cas) (induced by 10 mM SN and 100 ng/ml a-Fas) is time-dependent and earlier detectable in HeLa-Cx43 cells compared with HeLa-CTL cells 20 15 10 5 25 30 untreated 1 10 100 200 SN (M) -FAS (ng/ml) apoptotic cells (%) CTL Cx43 * # * # * # * # untreated + -Fas HeLa-Cx43 HeLa-Cx43 PI annexin V-FITC annexin V-FITC 104 104 103 103 102 102 101 101 100 100 104 103 102 101 100 104 103 102 101 100 FL2-H FL2-H FL1-H FL1-H 20 15 10 5 25 30 untreated 1 10 100 200 SN (M) -FAS (ng/ml) apoptotic cells (%) CTL Cx43 * # * # * # * # 4 untreated HeLa-Cx43 PI annexin V-FITC 104 104 103 103 102 102 101 101 100 100 FL2-H FL1-H Cx43 h SN (10 M) 0 8 16 6 CTL 0 8 16 6 -FAS (100 ng/ml) 0 4 6 2 0 4 6 2 CTL Cx43 h -cl. Parp -GAPDH -cl. Cas7 Figure 1 Cx43 expression enhances apoptosis of HeLa cells. (a) Representative contour plots of untreated and a-Fas (100 ng/ml, 5 h)-treated HeLa-Cx43 cells. The amount of apoptotic cells was determined by annexin V-FITC/PI staining and is displayed in the lower right quadrant (grey). (b) SN- or a-Fas-induced apoptotic cell death of HeLa cells is significantly increased by the expression of Cx43. Apoptosis of HeLa-Cx43 and HeLa-CTL cells untreated or treated with increasing concentrations of SN or a-Fas for 5 h was detected by annexin V-FITC/PI labelling. Mean±S.E.M., *Po0.05 versus untreated (NG); #Po0.05 versus CTL cells (NG); nZ8 in at least three different cell cultures. (c) Representative western blots show that apoptotic cleavage of Parp (cl. Parp) and clevage of caspase-7 (cl. Cas) (induced by 10 mM SN and 100 ng/ml a-Fas) is time-dependent and earlier detectable in HeLa-Cx43 cells compared with HeLa-CTL cells untreated and SN-treated cells (10 mM) showed a low basal PI uptake, which was significantly increased in the presence of the hemichannel opener ATP (Figure 5b). This ATP-induced enhancement was abolished after pretreatment with the inhibitory Pep (50 mM). The ConPep did not reduce the ATP-induced PI uptake in HeLa-Cx43 cells (mean fluores- cence of single cells (mean grey) untreated: 149±1; SN: 155±1; ATP: 194±3; ATP þ Pep: 155±1; ATP þ ConPep: 207±2; in three different cultures, nZ80–160; Po0.001 ATP/ATP þ ConPep versus untreated and SN). Results corresponds well with the amount of GJ-deficient cells responding with a Ca2 þ i increase to stimulation with SN (Figure 6b). The inhibition of IP3 receptors by xestospongin C reduced the rate of SN-induced apoptosis only in HeLa-Cx43 but not in HeLa-CTL cells (Figure 6c). untreated and SN-treated cells (10 mM) showed a low basal PI uptake, which was significantly increased in the presence of the hemichannel opener ATP (Figure 5b). This ATP-induced enhancement was abolished after pretreatment with the inhibitory Pep (50 mM). The ConPep did not reduce the ATP-induced PI uptake in HeLa-Cx43 cells (mean fluores- cence of single cells (mean grey) untreated: 149±1; SN: 155±1; ATP: 194±3; ATP þ Pep: 155±1; ATP þ ConPep: 207±2; in three different cultures, nZ80–160; Po0.001 ATP/ATP þ ConPep versus untreated and SN). Discussion In this study, we have shown that the enhancing effect of Cx expression on apoptosis in HeLa cells is dependent on their channel-forming capacity and their influence on channel permeability. In contrast, channel-independent effects, such as that observed to have a role in migration in the same type of cells5 or in cell proliferation as shown in Neuro2a cells,28 could not be observed. Thus, our study confirms and extends previous reports on a decisive role of gap junctional communication on augmentation of apoptosis in tumour cell lines such as BC31 (a rat bladder carcinoma cell line)29 or C6 glioma cells,30 as well as in neuronal cells, for example, astrocytes31 and Neuro2a cells.32 GJ channels enhance the amount of cells responding to SN with a Ca2 þ i increase. Ca2 þ and inositol triphosphate (IP3) are known to represent potential proapoptotic signal molecules, which are small enough to pass through GJs. We, therefore, analysed changes of intracellular free calcium (Ca2 þ i) in cells without GJs (CTL and Cx43CT-GFP) and in cells with functional GJs (Cx43, Cx43NT-GFP) after treat- ment with SN. SN (10 mM) increased Ca2 þ i in 84±5% of cells expressing full-length Cx43 and 59±8% of cells expressing the N-terminal channel-building part of Cx43 (Cx43NT-GFP; Figure 6a). In contrast, only 27±7% of HeLa cells expressing no Cx (CTL) or 28±7% of HeLa cells expressing the channel-incompetent cytoplasmic CT of Cx43 (Cx43CT-GFP) reacted to SN with an increase of Ca2 þ i. Our conclusion of gap junctional communication being a prerequisite for the augmented apoptosis is based on several lines of evidence. Firstly, the pharmacologic inhibition of GJs decreased the extent of SN- or a-Fas-induced apoptosis. In agreement with an inhibitory action of meclofenamic acid and heptanol on GJ coupling,33 we have shown that GJs remain open during the development of apoptosis and this concurs with results from other groups.30,34 Although the inhibitors used, meclofenamic acid and heptanol, may have unspecific effects, they did not directly interfere with apoptotic signalling processes since they did not affect the rate of apoptosis in untreated cells. Second, the decisive role of gap junctional communication but not of channel-independent effects of Inhibition of IP3 receptor-mediated Ca2 þ release dimin- ish apoptosis in GJ-coupled HeLa-Cx43 cells. Results The potential release of proa- poptotic signals via Cx hemichannels, which may act in a paracrine manner, was investigated by specific blockade of Cx43 hemichannels using an inhibitory Pep (50 mM),27 which does not affect gap junctional communication (HeLa-Cx43 cells; Ca2 þ spreading due to mechanical stimulation; untreated: 25±2 cells; control peptide (ConPep): 28±3 cells; Pep: 27±2 cells; n ¼ 9 in three different cell culture wells). The amount of apoptosis of HeLa-Cx43 cells with SN (10 mM) or a-Fas (100 ng/ml) was not changed under treatment with the hemichannel-blocking Pep (SN þ Pep; Fasþ Pep; Figure 5a). Apoptosis of cells incubated with the inhibitory Pep alone was as low as that of untreated cells or of cells incubated with the ConPep (Figure 5a). The efficiency of the hemichannel-blocking Pep was tested by measuring the uptake of PI via hemichannels in HeLa-Cx43 cells. Both Cell Death and Disease Gap junctions promote apoptosis P Kameritsch et al 3 3 -FAS (100 ng/ml) 0 4 6 2 0 4 6 2 CTL Cx43 h -cl. Parp -GAPDH -cl. Cas7 20 15 10 5 25 30 untreated 1 10 100 200 SN (M) -FAS (ng/ml) apoptotic cells (%) CTL Cx43 * # * # * # * # untreated + -Fas HeLa-Cx43 HeLa-Cx43 PI annexin V-FITC annexin V-FITC Cx43 h SN (10 M) 0 8 16 6 CTL 0 8 16 6 104 104 103 103 102 102 101 101 100 100 104 103 102 101 100 104 103 102 101 100 FL2-H FL2-H FL1-H FL1-H Figure 1 Cx43 expression enhances apoptosis of HeLa cells. (a) Representative contour plots of untreated and a-Fas (100 ng/ml, 5 h)-treated HeLa-Cx43 cells. The amount of apoptotic cells was determined by annexin V-FITC/PI staining and is displayed in the lower right quadrant (grey). (b) SN- or a-Fas-induced apoptotic cell death of HeLa cells is significantly increased by the expression of Cx43. Apoptosis of HeLa-Cx43 and HeLa-CTL cells untreated or treated with increasing concentrations of SN or a-Fas for 5 h was detected by annexin V-FITC/PI labelling. Mean±S.E.M., *Po0.05 versus untreated (NG); #Po0.05 versus CTL cells (NG); nZ8 in at least three different cell cultures. (c) Representative western blots show that apoptotic cleavage of Parp (cl. Parp) and clevage of caspase-7 (cl. Discussion GAPDH, glyceraldehyde 3-phosphate dehydrogenase -GAPDH Cx43 -Cx43 CTL CTL Cx37 -Cx37 Cx40 CTL -Cx40 Cx37 Cx43 CTL Cx40 CTL Cx37 Cx40 Cx43 fold increase of apoptotic cells 0 1 2 3 4 5 6 * # * * apoptosis cell coupling stained cells CTL Cx37 Cx40 Cx43 0 5 10 15 20 * # * # Figure 2 The rate of apoptosis is dependent on the Cx type expressed and correlates to the GJ permeability. (a) Western blot analysis for the expression of Cx37, Cx40 and Cx43 in stably transfected HeLa cells compared with empty vector-transfected HeLa (CTL). (b) Immunofluorescence stainings of Cx proteins in stably transfected HeLa cells demonstrate typical localisation at the membrane of adjacent cells. HeLa-CTL cells were used as controls and showed no Cx43 expression by staining for Cx43. (c) Apoptosis (induced by 1 mM SN, 3 h) of stably transfected HeLa cells is dependent on the Cx type expressed and significantly increased by expression of Cx40 or Cx43 compared with HeLa-CTL. Apoptosis was determined by annexin V-FITC/PI labelling and fold increase of apoptotic cells is expressed as mean±S.E.M.; *Po0.05 versus CTL; #Po0.05 versus Cx37; nZ5 in at least three different cell cultures. (d) Gap junctional cell coupling of HeLa cells varies with the Cx type expressed and correlates with the rate of apoptosis. Cell coupling was measured by dye spreading (Alexa Fluor 488). The number of dye-stained cells is displayed as mean±S.E.M. (nZ18 dye injections in Z3 different cell cultures; *Po0.05 versus CTL; #Po0.05 versus Cx37; NG). GAPDH, glyceraldehyde 3-phosphate dehydrogenase untreated 0 5 10 15 20 25 30 MH SN+MH SN Fas Fas+MH apoptotic cells (%) * * Figure 3 Impact of gap junctional communication on apoptosis of HeLa cells. Apoptosis induced by SN (1 mM, 5 h) or a-Fas (100 ng/ml, 5 h) in HeLa-Cx43 cells is significantly reduced by blocking the GJ channels with meclofenamic acid (M, 100 mM) and heptanol (H, 0.25 mM). Apoptosis was measured by annexin V-FITC/PI staining and quantified using flow cytometry. The percentage of apoptotic cells from the total cell number is expressed as mean±S.E.M. *Po0.05; NG; nZ3 in at least three different cell cultures untreated 0 5 10 15 20 25 30 MH SN+MH SN Fas Fas+MH apoptotic cells (%) * * apoptosis was only augmented in cells expressing the N-terminal channel-building part but not in cells expressing the C-terminal cytoplasmic part of Cx43. Discussion In another set of experiments (Figure 6b), preincubation (15 min) with the IP3 receptor blocker xestospongin C (Sigma Aldrich, Taufkirchen, Germany; 40 mM) restricted the SN-induced Ca2 þ increase to 36±12% of the cells (Cx43 þ SN: 99±1, Po0.001, n ¼ 8, in 3–4 different cultures). This number Inhibition of IP3 receptor-mediated Ca2 þ release dimin- ish apoptosis in GJ-coupled HeLa-Cx43 cells. In another set of experiments (Figure 6b), preincubation (15 min) with the IP3 receptor blocker xestospongin C (Sigma Aldrich, Taufkirchen, Germany; 40 mM) restricted the SN-induced Ca2 þ increase to 36±12% of the cells (Cx43 þ SN: 99±1, Po0.001, n ¼ 8, in 3–4 different cultures). This number Cell Death and Disease Gap junctions promote apoptosis P Kameritsch et al 4 4 Cx37 Cx43 CTL Cx40 -GAPDH Cx43 -Cx43 CTL CTL Cx37 -Cx37 Cx40 CTL -Cx40 cell coupling stained cells CTL Cx37 Cx40 Cx43 0 5 10 15 20 * # * # CTL Cx37 Cx40 Cx43 fold increase of apoptotic cells 0 1 2 3 4 5 6 * # * * apoptosis Figure 2 The rate of apoptosis is dependent on the Cx type expressed and correlates to the GJ permeability. (a) Western blot analysis for the expression of Cx37, Cx40 and Cx43 in stably transfected HeLa cells compared with empty vector-transfected HeLa (CTL). (b) Immunofluorescence stainings of Cx proteins in stably transfected HeLa cells demonstrate typical localisation at the membrane of adjacent cells. HeLa-CTL cells were used as controls and showed no Cx43 expression by staining for Cx43. (c) Apoptosis (induced by 1 mM SN, 3 h) of stably transfected HeLa cells is dependent on the Cx type expressed and significantly increased by expression of Cx40 or Cx43 compared with HeLa-CTL. Apoptosis was determined by annexin V-FITC/PI labelling and fold increase of apoptotic cells is expressed as mean±S.E.M.; *Po0.05 versus CTL; #Po0.05 versus Cx37; nZ5 in at least three different cell cultures. (d) Gap junctional cell coupling of HeLa cells varies with the Cx type expressed and correlates with the rate of apoptosis. Cell coupling was measured by dye spreading (Alexa Fluor 488). The number of dye-stained cells is displayed as mean±S.E.M. (nZ18 dye injections in Z3 different cell cultures; *Po0.05 versus CTL; #Po0.05 versus Cx37; NG). Discussion We conclude that the expression of functional Cx43 GJ channels is required for enhancement of apoptosis. A further piece of evidence that gap junctional communica- tion enhances apoptosis can be deducted from the observa- tion that the rate of apoptosis was clearly dependent on the permeability of the gap junctions as determined by the Cx s studied here: Cx43ZCx40ZCx374Cx-deficient controls. These Cx-dependent differences in GJ permeabilities are in agreement with own previous observations35 and another recently published study, showing the highest dye transfer for Cx43-composed channels, followed by Cx40 channels and lowest transfer for Cx37 channels.36 Of note, our results are based on the use of the GJ-permeant dye Alexa Fluor 488. Although the cellular exchange of GJ-permeant dyes between cells can differ with respect to their size and surface charge and may not represent the permeability of any potential proapoptotic molecule,36,37 it underpins a close connection between gap junctional permeability and augmentation of apoptosis in the experiments reported here. However, the finding that the spreading of Ca2 þ signals through GJs showed a similar behaviour than Alexa Fluor 488 suggests that the different permeabilities are not unique for this dye. Figure 3 Impact of gap junctional communication on apoptosis of HeLa cells. Apoptosis induced by SN (1 mM, 5 h) or a-Fas (100 ng/ml, 5 h) in HeLa-Cx43 cells is significantly reduced by blocking the GJ channels with meclofenamic acid (M, 100 mM) and heptanol (H, 0.25 mM). Apoptosis was measured by annexin V-FITC/PI staining and quantified using flow cytometry. The percentage of apoptotic cells from the total cell number is expressed as mean±S.E.M. *Po0.05; NG; nZ3 in at least three different cell cultures Cx43 could be confirmed by our results obtained in HeLa cells expressing truncated variants of Cx43. We have shown before that cells expressing the N-terminal part (NT) of Cx43 are able to form functional GJs, whereas cells expressing the C terminus of Cx43 did not.5 Accordingly, SN-induced Cell Death and Disease Gap junctions promote apoptosis P Kameritsch et al 5 5 for such a mechanism in our experimental setting. A hemichannel-blockingPep,27 which did not affect gap junctional coupling could not decrease SN- or a-Fas-induced apoptosis in Cx43-expressing HeLa cells. The fact that the cellular uptake of PI in the presence of ATP as reported elsewhere40 could be blocked by preincubation with the hemichannel-blocking Pep confirmed its expected inhibitory action in our experimental setting. Discussion Our study shows a role of gap junctional communication on apoptosis for both the exogenous and endogenous pathway as induced by two different stimuli. Although our study does not allow to conclude that there is a general role of gap junctional communication in the control of apoptosis, it is not limited to a single stimulus. Furthermore, a more general role of gap junctional communication is suggested by the observation that cells in a cluster are more susceptible to the induction of apoptosis than single cells.29,31 However, our experiments also clearly show that gap junctional commu- nication is not an essential prerequisite for the development of apoptosis but rather enhances its development. p g Obviously, the requirement of functional GJs for the augmentation of apoptosis suggests that some proapoptotic signals may be exchanged between apoptotic cells and their neighbours. Such signals cannot comprise caspases or proapoptotic regulator proteins like bad or bax, as these molecules are too large to pass GJs, which allow passage only for molecules up to 1.8 kDa.41 Small-molecule candi- dates that have been suggested to be potential death mediators when transferred via GJs are Ca2 þ, IP3 and cAMP.1,42 Several apoptosis-inducing stimuli are known to affect Ca2 þ i. Ca2 þ signals in turn can lead to the activation of caspases, the mainstream apoptosis executioners and open- ing of mitochondrial permeability transition pores (PTPs). PTP formation and opening result in the release of cytochrome C, which in turn has a role in the activation of the caspase cascade, and other proapoptotic proteins.1,43 The impact of the GJ-permeable molecule IP3 on apoptosis is related to IP3-triggered Ca2 þ release, whereby it contributes to the induction of apoptotic cell events.1,42 The importance of Ca2 þ as a proapoptotic signal has been shown by the treatment of cells with the calcium ionophore ionomycin or with thapsigargin. Such induced sustained elevation of Ca2 þ was sufficient to trigger apoptosis without any other apoptosis-inducing stimuli.44,45 Several studies have implicated a role of hemichannels in cell survival and death.8,10,38,39 Although Cx s can form hemichannels that could enable the release of pro-apoptotic signals independent of gap junctions, we found no evidence SN-induced increase in RFUs 25000 20000 15000 10000 5000 0 Cx43-GFP Cx43NT- GFP Cx43CT- GFP * * Figure 4 The channel-building part of Cx43 mediates enhanced apoptosis. Discussion SN-induced apoptosis (1 mM, 16 h) of HeLa cells expressing green fluorescent protein (GFP)-labelled Cx43 or truncated Cx43 proteins was determined by caspase activation. SN-induced apoptosis of HeLa cells expressing full-length Cx43 (Cx43- GFP) or the channel-building part of Cx43 (Cx43NT-GFP) was significantly enhanced compared with cells expressing the cytoplasmic part of Cx43 (Cx43CT- GFP). RFUs indicating activation of caspases in apoptotic cells are depicted as mean±S.E.M.; *Po0.05 versus Cx43CT-GFP, NG; nZ3 in different cell cultures SN-induced increase in RFUs 25000 20000 15000 10000 5000 0 Cx43-GFP Cx43NT- GFP Cx43CT- GFP * * Figure 4 The channel-building part of Cx43 mediates enhanced apoptosis. SN-induced apoptosis (1 mM, 16 h) of HeLa cells expressing green fluorescent protein (GFP)-labelled Cx43 or truncated Cx43 proteins was determined by caspase activation. SN-induced apoptosis of HeLa cells expressing full-length Cx43 (Cx43- GFP) or the channel-building part of Cx43 (Cx43NT-GFP) was significantly enhanced compared with cells expressing the cytoplasmic part of Cx43 (Cx43CT- GFP). RFUs indicating activation of caspases in apoptotic cells are depicted as mean±S.E.M.; *Po0.05 versus Cx43CT-GFP, NG; nZ3 in different cell cultures g We analysed whether changes of Ca2 þ i could be involved into the enhanced rate of apoptosis observed in cells coupled by gap junctions. Indeed, treatment with SN resulted in a fast increase of Ca2 þ i. An increase of Ca2 þ i upon treatment with SN has been described previously in lymphoblastoid cells.46 However in cells without gap junctional coupling only a minor However, in cells without gap junctional coupling, only a minor PIuptake (meang rey) untreated SN ATP ATP+Pep ATP+ConPep 0 100 120 140 160 180 200 220 * * apoptotic cells (%) a b untreated 0 5 10 15 20 25 30 ConPep SN+ConPep SN Fas Fas+ConPep Pep SN+Pep Fas+Pep Figure 5 Effect of hemichannels on apoptosis. (a) The inhibition of Cx43 hemichannels with a blocking Pep (50 mM, Pep) does not affect the rate of apoptosis induced by SN (10 mM, 5 h) or a-Fas (100 ng/ml, 5 h) in HeLa-Cx43 cells. A non-inhibitory ConPep (50 mM) was used as a control. Apoptosis was measured by annexin V-FITC/PI staining and quantified using flow cytometry. The percentage of apoptotic cells from the total cell number is expressed as mean±S.E.M.; nZ6 in at least three different cell cultures. Discussion (b) The uptake of PI (mean red fluorescence of single cells) by HeLa-Cx43 cells from the culture medium could be stimulated by opening the hemichannels with ATP (50 mM) and was efficiently blocked by preincubation with a hemichannel-blocking Pep (50 mM). Treatment with SN (10 mM) did not affect the PI uptake. A non-inhibitory Pep (ConPep) was used as a control. PI uptake of single cells is displayed as mean±S.E.M.; nZ80–160 cells in at least three different cell cultures *Po0.001 versus untreated, SN and ATP þ ConPep, NG Cell Death and D PIuptake (meang rey) untreated SN ATP ATP+Pep ATP+ConPep 0 100 120 140 160 180 200 220 * * apoptotic cells (%) a b untreated 0 5 10 15 20 25 30 ConPep SN+ConPep SN Fas Fas+ConPep Pep SN+Pep Fas+Pep a Figure 5 Effect of hemichannels on apoptosis. (a) The inhibition of Cx43 hemichannels with a blocking Pep (50 mM, Pep) does not affect the rate of apoptosis induced by SN (10 mM, 5 h) or a-Fas (100 ng/ml, 5 h) in HeLa-Cx43 cells. A non-inhibitory ConPep (50 mM) was used as a control. Apoptosis was measured by annexin V-FITC/PI staining and quantified using flow cytometry. The percentage of apoptotic cells from the total cell number is expressed as mean±S.E.M.; nZ6 in at least three different cell cultures. (b) The uptake of PI (mean red fluorescence of single cells) by HeLa-Cx43 cells from the culture medium could be stimulated by opening the hemichannels with ATP (50 mM) and was efficiently blocked by preincubation with a hemichannel-blocking Pep (50 mM). Treatment with SN (10 mM) did not affect the PI uptake. A non-inhibitory Pep (ConPep) was used as a control. PI uptake of single cells is displayed as mean±S.E.M.; nZ80–160 cells in at least three different cell cultures *Po0.001 versus untreated, SN and ATP þ ConPep, NG Cell Death and Disease 0 20 40 60 80 100 Cx43NT- GFP Cx43 Cx43CT- GFP CTL cells with elevated Ca2+ i (%) Cx43+SN Cx43+SN xesto 0 20 40 60 80 100 cells with elevated Ca2+ i (%) * * * 0 3 1 2 4 CTL Cx43 untreated SN SN+xesto fold increase of apoptosis * * * * # Figure 6 The immediate Ca2 þ i response is increased in cells expressing functional Cx43 channels. Discussion (a) The number of cells responding within 3 min with a Ca2 þ i increase due to SN treatment (10 mM) was significantly enhanced in Cx43- and Cx43NT-expressing HeLa cells compared with HeLa-CTL or HeLa-Cx43CT cells. The percentage of cells with a Ca2 þ i increase from the total cell number is expressed as mean±S.E.M.; *Po0.05 versus CTL/Cx43CT, nZ8 in at least three different cell cultures. In another series of experiments (b), the Ca2 þ increase induced by SN (10 mM) was blocked by preincubation (15 min) with xestospongin C (xesto, 40 mM). The percentage of cells with a Ca2 þ i increase from the total cell number is expressed as mean±S.E.M.; *Po0.05, NG; n ¼ 8 in three different cell cultures. (c) Inhibition of IP3-mediated Ca2 þ release (by xesto, 40 mM) reduces significantly SN (10 mM, 5 h)-induced apoptosis of HeLa-Cx43 cells but does not affect Cx-deficient control cells. Apoptosis was determined by annexin V-FITC/PI labelling and fold increase of apoptotic cells is expressed as mean±S.E.M.; *Po0.05 versus corresponding untreated; #Po0.05 versus Cx43 SN; n ¼ 6 in three different cell cultures Gap junctions promote apoptosis P Kameritsch et al Gap junctions promote apoptosis P Kameritsch et al 6 6 0 20 40 60 80 100 Cx43NT- GFP Cx43 Cx43CT- GFP CTL cells with elevated Ca2+ i (%) Cx43+SN Cx43+SN xesto 0 20 40 60 80 100 cells with elevated Ca2+ i (%) * * * P Kameritsch et al 6 0 3 1 2 4 CTL Cx43 untreated SN SN+xesto fold increase of apoptosis * * * * # SN+xesto Figure 6 The immediate Ca2 þ i response is increased in cells expressing functional Cx43 channels. (a) The number of cells responding within 3 min with a Ca2 þ i increase due to SN treatment (10 mM) was significantly enhanced in Cx43- and Cx43NT-expressing HeLa cells compared with HeLa-CTL or HeLa-Cx43CT cells. The percentage of cells with a Ca2 þ i increase from the total cell number is expressed as mean±S.E.M.; *Po0.05 versus CTL/Cx43CT, nZ8 in at least three different cell cultures. In another series of experiments (b), the Ca2 þ increase induced by SN (10 mM) was blocked by preincubation (15 min) with xestospongin C (xesto, 40 mM). Discussion The percentage of cells with a Ca2 þ i increase from the total cell number is expressed as mean±S.E.M.; *Po0.05, NG; n ¼ 8 in three different cell cultures. (c) Inhibition of IP3-mediated Ca2 þ release (by xesto, 40 mM) reduces significantly SN (10 mM, 5 h)-induced apoptosis of HeLa-Cx43 cells but does not affect Cx-deficient control cells. Apoptosis was determined by annexin V-FITC/PI labelling and fold increase of apoptotic cells is expressed as mean±S.E.M.; *Po0.05 versus corresponding untreated; #Po0.05 versus Cx43 SN; n ¼ 6 in three different cell cultures part responded with a Ca2 þ i increase, whereas virtually all cells responded when the cells were coupled. Interestingly, pretreatment with the IP3 receptor inhibitor xestospongin C47 limited the calcium response to a fraction of cells, which was numerically identical with the fraction of cells that responded in the absence of gap junctions. We have shown before that xestospongin C reliably abolished IP3-mediated Ca2 þ responses.33 Therefore, our findings are consistent with the view that SN induced an IP3-independent increase of Ca2 þ i in SN-sensitive cells. This Ca2 þ signal could have spread to neighbouring cells via GJs, which is also consistent with our findings that part of the cells responded with a delayed Ca2 þ i increase (up to 30 s) upon SN treatment (data not shown). As shown before, an increase of Ca2 þ i can induce a secondary release of calcium via IP3 receptors,48 which in our setting may have spread via GJs to non-SN-responsive neighbouring cells to induce increases of Ca2 þ i as well. Thus, both absence of gap junctional communication and inhibition of IP3 receptors may restrict apoptosis by the same amount as observed here. Discussion We have recently described that a similar mechanism plays a pivotal role in the Ca2 þ response of endothelial cells to stimulation with histamine or ATP.49 Ca2 þ i increases were also reported for Fas-initiated apoptosis with a sustained increase in Ca2 þ i commencing between 1 and 2 h after treatment.50,51 granulosa cells52 or astrocytes.53 A so-called bystander death induced by gap junctional spreading of cell-killing signals from cells undergoing apoptosis to healthy surrounding cells has been described for several apoptosis-inducing condi- tions.21,22 Although the physiologic role of a spread of apoptosis signals to potentially healthy neighbouring cells remains a matter of debate, the passage of ‘death signals’, for example, from lethally irradiated cells to their neighbours via GJs54,55 seems to be very promising for cancer therapies.56 GJ-mediated bystander effects are described also for a few diseases, for example, retinitis pigmentosa57 or HIV-1 infection,58 and may represent a potentially important therapeutic principle in these disease states. part responded with a Ca2 þ i increase, whereas virtually all cells responded when the cells were coupled. Interestingly, pretreatment with the IP3 receptor inhibitor xestospongin C47 limited the calcium response to a fraction of cells, which was numerically identical with the fraction of cells that responded in the absence of gap junctions. We have shown before that xestospongin C reliably abolished IP3-mediated Ca2 þ responses.33 Therefore, our findings are consistent with the view that SN induced an IP3-independent increase of Ca2 þ i in SN-sensitive cells. This Ca2 þ signal could have spread to neighbouring cells via GJs, which is also consistent with our findings that part of the cells responded with a delayed Ca2 þ i increase (up to 30 s) upon SN treatment (data not shown). As shown before, an increase of Ca2 þ i can induce a secondary release of calcium via IP3 receptors,48 which in our setting may have spread via GJs to non-SN-responsive neighbouring cells to induce increases of Ca2 þ i as well. Thus, both absence of gap junctional communication and inhibition of IP3 receptors may restrict apoptosis by the same amount as observed here. Discussion Apoptosis was measured with the sulforhodamine FLICA apoptosis detection kit (Immunochemistry Technologies, Biomol, Hamburg, Germany). The red fluorescent inhibitor of caspases SR-VAD-FMK detects activated caspases (caspase-1, -3, -4, -5, -6, -7, -8 and -9) of apoptotic cells. Untreated or SN-treated (1 mM, 16 h) HeLa cells expressing full-length Cx43-GFP, Cx43NT-GFP or Cx43CT-GFP were detached with trypsin-EDTA (Sigma Aldrich) and 300 ml cell suspension (5  106 cells per ml) were stained with FLICA reagent according to the manufacturer’s instructions. After staining, the cells were washed three times with 1  wash buffer and cell concentrations of untreated and SN-treated cells were determined again. After equilibration of the cell concentrations, the cells were resuspended in PBS and the red fluorescence intensity of sulforhodamine (RFU) was measured in a fluorescence plate reader at excitation/emission wavelengths of 550/595 nm. Annexin V-FITC/PI staining. The annexin V-FITC apoptosis detection kit (BD Biosciences, Heidelberg, Germany) was used according to the manufacturer’s recommendations. The cells were treated as indicated, detached with Accutase (PAA Laboratories, Coelbe, Germany) and collected by centrifugation (1500 r.p.m., 5 min). Cell pellets were washed with phosphate-buffered saline (PBS), resuspended in 1  binding buffer (0.01 M HEPES/NaOH, pH 7.4, 140 mM NaCl and 2.5 mM CaCl2), and stained with annexin V-FITC and PI for 15 min at room temperature in the dark. A total of 10 000 cells of each sample were analysed by fluorescence-activated cell sorting (FACSort; BD Bioscience). Apoptotic cells were defined as annexin V-FITC-positive and PI-negative cells. Analysis of GJ-independent transfer of proapoptotic signals via hemichannels. The effect of hemichannels on the rate of apoptosis was analysed with a hemichannel-blocking Pep. HeLa-Cx43 cells were incubated with a Cx43-specific Pep (H-Val-Asp-Cys-Phe-Leu-Ser-Arg-Pro-Thr-Glu-Lys-Thr-OH; 50 mM; Biosyntan, Berlin, Germany), which reportedly inhibits hemichannels at a concentration of 50 mM by affecting the extracellular loop of Cx43.27 For control experiments, cells were incubated with 50 mM ConPep (H-Gly-Asp-Glu-Gln-Ser- Ala-Phe-Arg-Cys-Asn-Thr-Gln-OH). Apoptosis was induced by the addition of SN (10 mM) or a-Fas (100 ng/ml) for 5 h and the amount of apoptotic cells was measured by annexin V-FITC/PI staining. Western blot analysis. Empty vector-transfected HeLa cells (CTL) or HeLa cells stably expressing Cx37, Cx40 or Cx43 were seeded in 6-well plates and lysed in Laemmli buffer59 the next day. The samples were boiled for 5 min and size-separated by SDS-PAGE using 8–16% Tris-glycine gels (Thermo Scientific, Bonn, Germany). Discussion On the next day, the cells were treated with 10 mM SN (Sigma Aldrich) or 100 ng/ml a-Fas (Millipore) for the indicated time points and lysed in Laemmli buffer.59 For detection of cleaved Parp, an a-Parp antibody (1 : 500; Cell Signaling, NEB, Frankfurt am Main, Germany), and for cleaved caspase-7, an a-caspase-7 antibody (1 : 500; Cell Signaling), was used. Detection of GAPDH (a-GAPDH, 1 : 10000; Chemicon, Merck Chemicals, Schwalbach, Germany) was used to demonstrate equal loading. The Ca2þ-sensitive dye was alternatively excited at 340 and 380 nm and the signal was detected at 505 nm with a computerised system (Till Photonics). Frames at 340 and 380nm of the analysed areas (640nm  480nm) were stored every 500ms for 3 min and the signal ratio corrected for the background was determined for each pixel after the experiment. Based on changes of the mean ratio of single cells over time, the percentage of cells showing a Ca2 þ i increase due to stimulation (reacting cells per cells in the visible area) was calculated. No attempt was made to calculate the exact Ca2 þ i concentration from the ratio. Immunofluorescence staining. HeLa cells expressing Cx37, Cx40 or Cx43 or HeLa-CTL cells were seeded on glass coverslips. On the next day, the cells were fixed with 3.7% formaldehyde in PBS for 20min at room temperature. After rinsing with PBS, cells were permeabilised with 0.1% Triton X-100 (AppliChem) in PBS for 4min. Unspecific antibody binding was blocked with PBS containing 0.5% BSA for 1h. Cells were incubated with rabbit a-Cx37 (Alpha Diagnostic; 1:100), rabbit a-Cx40 (Alpha Diagnostic; 1:100) or rabbit a-Cx43 (Sigma Aldrich; 1:100) overnight at 41C. The cells were washed and incubated with a secondary antibody (1:200) coupled to the fluorochrome Alexa Fluor 488 (Invitrogen) for 1h at room temperature. Coverslips were mounted and expression and localisation of the Cx proteins were analysed using confocal microscopy (Leica, Wetzlar, Germany). Cells were stimulated mechanically or by the addition of SN (10 mM). Mechanical stimulation of single cells by touching with glass pipettes (tip diameter 1 mm) increased the Ca2 þ i of the stimulated cell. In the presence of apyrase (Sigma Aldrich; 50 U/ml), which degraded the ATP released due to the stimulation, the Ca2 þ signal spread to neighbouring cells via gap junctions. The number of cells showing an elevated Ca2 þ level (except of the stimulated cell) was counted. Discussion The proteins were electrophoretically transferred to a Hybond-P membrane (Amersham, GE Healthcare, Freiburg, Germany) at 0.8 mA/cm2 for 1 h and unspecific antibody binding was blocked by 5% skimmed milk powder (AppliChem, Darmstadt, Germany) in PBS solution containing 0.1% Tween-20 (Sigma Aldrich) for 1 h at room temperature. The membranes were incubated with rabbit a-Cx37 (1 : 1000; Alpha Diagnostic, Biotrend, Koeln, Germany), rabbit a-Cx40 (1 : 1000; Alpha Diagnostic) or rabbit a-Cx43 (1 : 1000; Sigma Aldrich) overnight at 4 1C. After washing with PBS–0.1% Tween, the blots were incubated for 2 h with the secondary antibody coupled to horseradish peroxidase (1 : 1000; Calbiochem, Merck, Darmstadt, Germany). Primary antibodies were diluted in 5% bovine serum albumin (BSA; AppliChem) in PBS–0.1% Tween and secondary antibodies in 5% skimmed milk powder in PBS–0.1% Tween. The blots were washed four times for 10 min each and bound antibodies were detected using a chemiluminescence detection kit for horseradish peroxidase (AppliChem). PI uptake via hemichannels. To analyse the activity of hemichannels, HeLa-Cx43 cells were incubated with PI (20 mg/ml, 10 min) and fluorescence images (excitation: 546 nm; emission: 570 nm; exposure time 1000 ms; experi- mental set-up: see calcium measurements) were taken immediately after washout of PI. The mean fluorescence (mean grey value) of single cells was calculated by the the Till Vision software (Till Photonics, Gra¨felfing, Germany). To verify that the PI uptake is not due to cell death, the cells were stained with Trypan blue afterwards and blue stained cells were excluded from calculations. Hemichannels were activated by ATP (50 mM). Measurement of the Ca2 þ i. Intracellular changes of free Ca2 þ were detected with the Ca2 þ-sensitive dye Fura2 (Invitrogen). After incubation with 4 mM Fura2 solved in DMEM (30 min at 37 1C and 5% CO2), HeLa cells (grown on coverslips) were washed two times, transferred to the experimental chamber (which had a wide opening on the top) and incubated in HEPES (pH 7.4; 125 mM NaCl, 3 mM KCl, 1.25 mM NaH2PO4, 2.5 mM CaCl2, 1.5 mM MgCl, 10 mM glucose). The chamber filled with 200 ml HEPES was mounted on an inverted microscope (Axiovert S100; Zeiss, Go¨ttingen, Germany). To analyse the apoptotic cleavage of caspase-7 and Parp in HeLa-Cx43 and HeLa-CTL cells, the cells were seeded in 6-well-plates to 80% confluence. Discussion We have recently described that a similar mechanism plays a pivotal role in the Ca2 þ response of endothelial cells to stimulation with histamine or ATP.49 Ca2 þ i increases were also reported for Fas-initiated apoptosis with a sustained increase in Ca2 þ i commencing between 1 and 2 h after treatment.50,51 In conclusion, our study has shown that Cx expression enhances apoptosis induction. This is not a class effect but varies considerably dependent on the type of the Cx as studied here for Cx being expressed in vascular tissue. Our results suggest that this effect is due to the transfer of proapoptotic signals, among which IP3 may play a significant role. Thus, gap junctional communication and the control of gap junctional permeability by variation of Cx expression may be a potential target for therapeutic control of apoptosis. Materials and Methods Cell cultures. HeLa cells stably transfected with murine Cx37, murine Cx40 or rat Cx43 were kindly provided by Dr. Klaus Willecke (University of Bonn, Bonn, Germany). HeLa cells transfected with the empty vector pBEHpac18 (CTL; kindly provided by Dr. Willecke, Bonn, Germany) using SuperFect (Qiagen, Hilden, In agreement with our study, it has been reported that the blockade of intercellular communication via GJs attenuated the extent of apoptosis, for example, in BC31 cells,29 Cell Death and Disease 7 Gap junctions promote apoptosis P Kameritsch et al amount of apoptotic cells was quantified by flow cytometry with annexin V-FITC staining as described above. amount of apoptotic cells was quantified by flow cytometry with annexin V-FITC staining as described above. amount of apoptotic cells was quantified by flow cytometry with annexin V-FITC staining as described above. Germany), which served as controls. Generation of stably transfected HeLa cells expressing the NT (amino acids (aa) 1–257, Cx43NT-GFP) or the CT of Cx43 (aa 257–382, Cx43CT-GFP) was described previously.5 Cells were cultured in Dulbecco’s modified Eagle’s medium (DMEM; Invitrogen, Life Technologies, Darmstadt, Germany) with 10% new born calf serum (Biochrom, Berlin, Germany), penicillin (100 U/ml; Sigma Aldrich) and streptomycin (100 mg/ml; Sigma Aldrich) at 37 1C and 5% CO2. Growth medium of stably transfected HeLa- CTL, HeLa-Cx37, HeLa-Cx40 and HeLa-Cx43 was supplemented with puromycin (1 mg/ml; Sigma Aldrich) and of HeLa-Cx43NT-GFP and HeLa-Cx43CT-GFP with zeocin (200 mg/ml; Invitrogen, Life Technologies). Apoptosis was induced with SN (Sigma Aldrich) or a-Fas antibody (Millipore Merck, Schwalbach, Germany) as indicated. FLICA staining. Discussion The dye was injected using a dye-filled borosilicate micropipette (at a tip pressure of 60 mm Hg for 0.6 s, tip diameter o1 mm) connected to an injecting system (FemtoJet; Eppendorf, Wesseling- Berzdorf, Germany). The fluorescent dye was excited at 488 nm and fluorescence signals were detected using a long-pass emission filter lemZ515 nm. Following dye injection, images were captured using a digital camera (Imago; Till Photonics) that was mounted on the inverted microscope (Axiovert S100; Zeiss). To assess cellular coupling, the total number of dye-stained cells at the 5-min postinjection timepoint was counted. 17. Halestrap AP. Mitochondria and preconditioning: a connexin connection? Circ Res 2006; 99: 10–12. 18. Li H, Brodsky S, Kumari S, Valiunas V, Brink P, Kaide J et al. Paradoxical overexpression and translocation of connexin43 in homocysteine-treated endothelial cells. Am J Physiol Heart Circ Physiol 2002; 282: H2124–H2133. 19. Rodriguez-Sinovas A, Boengler K, Cabestrero A, Gres P, Morente M, Ruiz-Meana M et al. Translocation of connexin 43 to the inner mitochondrial membrane of cardiomyocytes through the heat shock protein 90-dependent TOM pathway and its importance for cardioprotection. Circ Res 2006; 99: 93–101. 20. Huang RP, Fan Y, Hossain MZ, Peng A, Zeng ZL, Boynton AL. Reversion of the neoplastic phenotype of human glioblastoma cells by connexin 43 (cx43). Cancer Res 1998; 58: 5089–5096. Statistics. Gaussian distributed data were analysed for statistically significant differences by the Student’s t-test (two groups, unpaired data). Differences between more than two groups were determined by one-way ANOVA, followed by Student–Newman–Keuls method for multiple comparisons. Error probabilities of Pr0.05 were considered significant. All values are expressed as means±S.E.M. Non-Gaussian distributed data (indicated as ‘NG’ in the figure legends) were analysed by the non-parametric Mann–Whitney rank-sum test. For multiple comparisons, the Kruskal–Wallis test on ranks followed by pairwise multiple comparisons with Dunn’s method was used. Although these tests do not allow analysing differences of mean values, for descriptive reasons mean values are presented throughout the manuscript. Medians are not displayed as they did not differ from the means more than 20%. 21. Harada K, Nonaka T, Hamada N, Sakurai H, Hasegawa M, Funayama T et al. Heavy-ion- induced bystander killing of human lung cancer cells: role of gap junctional intercellular communication. Cancer Sci 2009; 100: 684–688. 22. Cusato K, Ripps H, Zakevicius J, Spray DC. Gap junctions remain open during cytochrome c-induced cell death: relationship of conductance to ‘bystander’ cell killing. Conflict of Interest Cell population dynamics (apoptosis, mitosis, and cell– cell communication) during disruption of homeostasis. Exp Cell Res 2000; 254: 257–268. 5. Behrens J, Kameritsch P, Wallner S, Pohl U, Pogoda K. The carboxyl tail of Cx43 augments p38 mediated cell migration in a gap junction-independent manner. Eur J Cell Biol 2010; 89: 828–838. 35. Kameritsch P, Khandoga N, Nagel W, Hundhausen C, Lidington D, Pohl U. Nitric oxide specifically reduces the permeability of Cx37-containing gap junctions to small molecules. J Cell Physiol 2005; 203: 233–242. 6. Bates DC, Sin WC, Aftab Q, Naus CC. Connexin43 enhances glioma invasion by a mechanism involving the carboxy terminus. Glia 2007; 55: 1554–1564. y 36. Weber PA, Chang HC, Spaeth KE, Nitsche JM, Nicholson BJ. The permeability of gap junction channels to probes of different size is dependent on connexin composition and permeant-pore affinities. Biophys J 2004; 87: 958–973. 7. Kameritsch P, Pogoda K, Pohl U. Channel-independent influence of connexin 43 on cell migration. Biochim Biophys Acta 2012; 1818: 1993–2001. 8. Decrock E, De Vuyst E, Vinken M, Van Moorhem M, Vranckx K, Wang N et al. Connexin 43 hemichannels contribute to the propagation of apoptotic cell death in a rat C6 glioma cell model. Cell Death Differ 2009; 16: 151–163. 37. Elfgang C, Eckert R, Lichtenberg-Frate H, Butterweck A, Traub O, Klein RA et al. Specific permeability and selective formation of gap junction channels in connexin-transfected HeLa cells. J Cell Biol 1995; 129: 805–817. 9. Decrock E, Vinken M, De Vuyst E, Krysko DV, D’Herde K, Vanhaecke T et al. Connexin- related signaling in cell death: to live or let die? Cell Death Differ 2009; 16: 524–536. 38. Contreras JE, Sanchez HA, Veliz LP, Bukauskas FF, Bennett MV, Saez JC. Role of connexin-based gap junction channels and hemichannels in ischemia-induced cell death in nervous tissue. Brain Res Brain Res Rev 2004; 47: 290–303. 10. Hur KC, Shim JE, Johnson RG. A potential role for cx43-hemichannels in staurosporin- induced apoptosis. Cell Commun Adhes 2003; 10: 271–277. nervous tissue. Brain Res Brain Res Rev 2004; 47: 290–303. 39. Plotkin LI, Manolagas SC, Bellido T. Transduction of cell survival signals by connexin-43 hemichannels. J Biol Chem 2002; 277: 8648–8657. 11. Kalvelyte A, Imbrasaite A, Bukauskiene A, Verselis VK, Bukauskas FF. Connexins and apoptotic transformation. Biochem Pharmacol 2003; 66: 1661–1672. 40. Baroja-Mazo A, Barbera-Cremades M, Pelegrin P. The participation of plasma membrane hemichannels to purinergic signaling. Conflict of Interest The authors declare no conflict of interest. 26. Yasui K, Kada K, Hojo M, Lee JK, Kamiya K, Toyama J et al. Cell-to-cell interaction prevents cell death in cultured neonatal rat ventricular myocytes. Cardiovasc Res 2000; 48: 68–76. Acknowledgements. We thank Silvia Mu¨nzing, Dorothea Go¨ssel and Katarzyna Stefanowski for excellent technical assistance and Dr. Klaus Willecke (Institute of Genetics, University of Bonn) for kindly providing HeLa cells, HeLa cells stably transfected with mouse Cx37, mouse Cx40 and rat Cx43 and the plasmid pBEHpac18. This work was supported by grants from the Deutsche Forschungs- gemeinschaft (DFG-PO 414/2-1 to UP and KP). 27. Danesh-Meyer HV, Kerr NM, Zhang J, Eady EK, O’Carroll SJ, Nicholson LF et al. Connexin43 mimetic peptide reduces vascular leak and retinal ganglion cell death following retinal ischaemia. Brain 2012; 135(Part 2): 506–520. 28. Moorby C, Patel M. Dual functions for connexins: Cx43 regulates growth independently of gap junction formation. Exp Cell Res 2001; 271: 238–248. 29. Krutovskikh VA, Piccoli C, Yamasaki H. Gap junction intercellular communication propagates cell death in cancerous cells. Oncogene 2002; 21: 1989–1999. 30. Lin JH, Weigel H, Cotrina ML, Liu S, Bueno E, Hansen AJ et al. Gap-junction-mediated propagation and amplification of cell injury. Nat Neurosci 1998; 1: 494–500. 1. Krysko DV, Leybaert L, Vandenabeele P, D’Herde K. Gap junctions and the propagation of cell survival and cell death signals. Apoptosis 2005; 10: 459–469. 31. Cotrina ML, Kang J, Lin JH, Bueno E, Hansen TW, He L et al. Astrocytic gap junctions remain open during ischemic conditions. J Neurosci 1998; 18: 2520–2537. 2. Rodriguez-Sinovas A, Cabestrero A, Lopez D, Torre I, Morente M, Abellan A et al. The modulatory effects of connexin 43 on cell death/survival beyond cell coupling. Prog Biophys Mol Biol 2007; 94: 219–232. 32. Andrade-Rozental AF, Rozental R, Hopperstad MG, Wu JK, Vrionis FD, Spray DC. Gap junctions: the ‘kiss of death’ and the ‘kiss of life’. Brain Res Brain Res Rev 2000; 32: 308–315. 3. Wei CJ, Xu X, Lo CW. Connexins and cell signaling in development and disease. Annu Rev Cell Dev Biol 2004; 20: 811–838. 33. Kameritsch P, Pogoda K, Ritter A, Munzing S, Pohl U. Gap junctional communication controls the overall endothelial calcium response to vasoactive agonists. Cardiovasc Res 2012; 93: 508–515. 4. Jiang JX, Gu S. Gap junction- and hemichannel-independent actions of connexins. Biochim Biophys Acta 2005; 1711: 208–214. 34. Wilson MR, Close TW, Trosko JE. Discussion Cell Death Differ 2006; 13: 1707–1714. 23. Frank DK, Szymkowiak B, Josifovska-Chopra O, Nakashima T, Kinnally KW. Single-cell microinjection of cytochrome c can result in gap junction-mediated apoptotic cell death of bystander cells in head and neck cancer. Head Neck 2005; 27: 794–800. 24. Blanc EM, Bruce-Keller AJ, Mattson MP. Astrocytic gap junctional communication decreases neuronal vulnerability to oxidative stress-induced disruption of Ca2 þ homeostasis and cell death. J Neurochem 1998; 70: 958–970. 25. Ozog MA, Siushansian R, Naus CC. Blocked gap junctional coupling increases glutamate- induced neurotoxicity in neuron–astrocyte co-cultures. J Neuropathol Exp Neurol 2002; 61: 132–141. Discussion In another set of experiments, SN was solved in double concentration (20 mM) in HEPES and 200 ml of this solution was rapidly added to the cells (120±14 cells per visual field were counted). Addition of the solution without stimuli did not change the Ca2 þ i signals. SN did not change the pH of the HEPES solution. IP3 receptors were inhibited by preincubation (15 min) with xestospongin C (40 mM). Detection of apoptosis in cells with inhibited gap junctional coupling. To investigate the impact of GJs on the rate of apoptosis, HeLa- Cx43 cells were incubated with meclofenamic acid (M; 100 mM; Sigma Aldrich) and heptanol (H; 0.25 mM; Sigma Aldrich), which nearly abolished the gap junctional coupling and minimised the drugs’ side effects.33 To induce apoptosis, the cells were additionally treated with 1 mM SN or 100 ng/ml a-Fas for 5 h and the Dye coupling. Gap junctional coupling was detected by injecting a GJ-permeable, membrane-impermeable fluorescent dye (3.5 mM Alexa Fluor 488 dissolved in 150 mM KCl; Invitrogen) into single cells and analysing the dye Cell Death and Disease Gap junctions promote apoptosis P Kameritsch et al Gap junctions promote apoptosis P Kameritsch et al 8 8 spreading within 5 min. The cell incubation unit and experimental settings were the same as for the Ca2 þ i measurement. The dye was injected using a dye-filled borosilicate micropipette (at a tip pressure of 60 mm Hg for 0.6 s, tip diameter o1 mm) connected to an injecting system (FemtoJet; Eppendorf, Wesseling- Berzdorf, Germany). The fluorescent dye was excited at 488 nm and fluorescence signals were detected using a long-pass emission filter lemZ515 nm. Following dye injection, images were captured using a digital camera (Imago; Till Photonics) that was mounted on the inverted microscope (Axiovert S100; Zeiss). To assess cellular coupling, the total number of dye-stained cells at the 5-min postinjection timepoint was counted. 16. Boengler K, Dodoni G, Rodriguez-Sinovas A, Cabestrero A, Ruiz-Meana M, Gres P et al. Connexin 43 in cardiomyocyte mitochondria and its increase by ischemic preconditioning. Cardiovasc Res 2005; 67: 234–244. spreading within 5 min. The cell incubation unit and experimental settings were the same as for the Ca2 þ i measurement. Conflict of Interest Biochim Biophys Acta 2013; 1828: 79–93. 12. Plotkin LI, Bellido T. Bisphosphonate-induced, hemichannel-mediated, anti-apoptosis through the Src/ERK pathway: a gap junction-independent action of connexin 43. Cell Commun Adhes 2001; 8: 377–382. 41. Neijssen J, Pang B, Neefjes J. Gap junction-mediated intercellular communication in the immune system. Prog Biophys Mol Biol 2007; 94: 207–218. 13. Iacobas DA, Urban-Maldonado M, Iacobas S, Scemes E, Spray DC. Array analysis of gene expression in connexin-43 null astrocytes. Physiol Genom 2003; 15: 177–190. 42. Foss B, Tronstad KJ, Bruserud O. Connexin-based signaling in acute myelogenous leukemia (AML). Biochim Biophys Acta 2010; 1798: 1–8. 14. Huang RP, Hossain MZ, Huang R, Gano J, Fan Y, Boynton AL. Connexin 43 (cx43) enhances chemotherapy-induced apoptosis in human glioblastoma cells. Int J Cancer 2001; 92: 130–138. 43. Orrenius S, Zhivotovsky B, Nicotera P. Regulation of cell death: the calcium-apoptosis link. Nat Rev Mol Cell Biol 2003; 4: 552–565. 44. Jiang S, Chow SC, Nicotera P, Orrenius S. Intracellular Ca2 þ signals activate apoptosis in thymocytes: studies using the Ca(2 þ )-ATPase inhibitor thapsigargin. Exp Cell Res 1994; 212: 84–92. 15. Sato H, Iwata H, Takano Y, Yamada R, Okuzawa H, Nagashima Y et al. Enhanced effect of connexin 43 on cisplatin-induced cytotoxicity in mesothelioma cells. J Pharmacol Sci 2009; 110: 466–475. Cell Death and Disease Gap junctions promote apoptosis P Kameritsch et al 9 9 54. Liu B, Wang Q, Yuan DD, Hong XT, Tao L. Berberine potentizes apoptosis induced by X-rays irradiation probably through modulation of gap junctions. Chin Med J (Engl) 2011; 124: 1221–1228. 45. Martikainen P, Kyprianou N, Tucker RW, Isaacs JT. Programmed death of nonproliferating androgen-independent prostatic cancer cells. Cancer Res 1991; 51: 4693–4700. g p p 46. Yan J, Khanna KK, Lavin MF. Defective radiation signal transduction in ataxia– telangiectasia cells. Int J Radiat Biol 2000; 76: 1025–1035. 55. Azzam EI, de Toledo SM, Little JB. Direct evidence for the participation of gap junction- mediated intercellular communication in the transmission of damage signals from alpha- particle irradiated to nonirradiated cells. Proc Natl Acad Sci USA 2001; 98: 473–478. 47. Miyamoto S, Izumi M, Hori M, Kobayashi M, Ozaki H, Karaki H et al. Xestospongin C, a selective and membrane-permeable inhibitor of IP(3) receptor, attenuates the positive inotropic effect of alpha-adrenergic stimulation in guinea-pig papillary muscle. Br J Pharmacol 2000; 130: 650–654. 56. Zhou H, Randers-Pehrson G, Suzuki M, Waldren CA, Hei TK. Conflict of Interest Genotoxic damage in non-irradiated cells: contribution from the bystander effect. Radiat Prot Dosimetry 2002; 99: 227–232. 48. Yamamoto K, Hashimoto K, Isomura Y, Shimohama S, Kato N. An IP3-assisted form of Ca2 þ-induced Ca2 þ release in neocortical neurons. NeuroReport 2000; 11: 535–539. 57. Ripps H. Cell death in retinitis pigmentosa: gap junctions and the ‘bystander’ effect. Exp Eye Res 2002; 74: 327–336. p 49. Kameritsch P, Pogoda K, Ritter A, Munzing S, Pohl U. Gap junctional communication 49. Kameritsch P, Pogoda K, Ritter A, Munzing S, Pohl U. Gap junctional communication controls the overall endothelial calcium response to vasoactive agonists. Cardiovasc Res 93: 508–515. controls the overall endothelial calcium response to vasoactive agonists. Cardiovasc Res 93: 508–515. 58. Oyaizu N, Adachi Y, Hashimoto F, McCloskey TW, Hosaka N, Kayagaki N et al. Monocytes express Fas ligand upon CD4 cross-linking and induce CD4 þ T cells apoptosis: a possible mechanism of bystander cell death in HIV infection. J Immunol 1997; 158: 2456–2463. 50. Chien MM, Zahradka KE, Newell MK, Freed JH. Fas-induced B cell apoptosis requires an increase in free cytosolic magnesium as an early event. J Biol Chem 1999; 274: 7059–7066. 59. Laemmli UK. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature 1970; 227: 680–685. 51. Scoltock AB, Bortner CD, St J Bird G, Putney JW Jr, Cidlowski JA. A selective requirement for elevated calcium in DNA degradation, but not early events in anti-Fas-induced apoptosis. J Biol Chem 2000; 275: 30586–30596. Cell Death and Disease is an open-access journal published by Nature Publishing Group. This work is licensed under a Creative Commons Attribution-NonCommercial- NoDerivs 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/ 52. Krysko DV, Mussche S, Leybaert L, D’Herde K. Gap junctional communication and connexin43 expression in relation to apoptotic cell death and survival of granulosa cells. J Histochem Cytochem 2004; 52: 1199–1207. 53. Nodin C, Nilsson M, Blomstrand F. Gap junction blockage limits intercellular spreading of astrocytic apoptosis induced by metabolic depression. J Neurochem 2005; 94: 1111–1123. Cell Death and Disease Cell Death and Disease
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Development and Field Validation of Lidocaine-Loaded Castration Bands for Bovine Pain Mitigation
Animals
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UVicSPACE: Research & Learning Repository Faculty of Science Faculty Publications Faculty of Science Faculty Publications Development and Field Validation of Lidocaine-Loaded Castration Bands for Bovine Pain Mitigation James W. Saville, Joseph A. Ross, Tyler Trefz, Crystal Schatz, Heather Matheson- Bird, Brenda Ralston, … & Merle Olson December 2020 © 2020 James W. Saville et al. This is an open access article distributed under the terms of the Creative Commons Attribution License. https://creativecommons.org/licenses/by/4.0/ s W. Saville et al. This is an open access article distributed under the terms of Commons Attribution License. https://creativecommons.org/licenses/by/4.0/ This article was originally published at: https://doi.org/10.3390/ani10122363 Development and Field Validation of Lidocaine-Loaded Castration Bands for Bovine Pain Mitigation James W. Saville, Joseph A. Ross, Tyler Trefz, Crystal Schatz, Heather Matheson- Bird, Brenda Ralston, … & Merle Olson December 2020 Received: 6 November 2020; Accepted: 8 December 2020; Published: 10 December 2020 Simple Summary: Castration is among the most common management procedures performed in the dairy and beef cattle industries. Despite the widely accepted benefits of castration, all castration methods produce pain and distress. While slower than other approaches, castration by banding is simple, inexpensive, and produces fewer complications. We have therefore focused the present study on developing herd-level pain mitigation during banded castration. Because lidocaine is effective at reducing pain and can be delivered topically, we have formulated lidocaine-loaded castration bands (LLBs) to deliver local pain relief to calves and bulls during banded castration. Laboratory results indicated a rapid release of lidocaine for the first 30 min, followed by a slow release for at least 48 h. Field studies indicated that, for both lidocaine delivery into tissues and pain mitigation, LLBs performed at least as well as standard lidocaine injections in the short term and outperformed lidocaine injections in the long term. LLBs delivered therapeutic quantities of lidocaine into scrotal tissues over a period of at least seven days in cattle. This approach would provide long-term pain mitigation to the animals and, by avoiding surgery or the administration of injections, would also decrease the time and handling costs for the producer. Abstract: Castration is among the most common management procedures performed in the dairy and beef cattle industries and is mainly performed by surgery or elastic banding. Despite the various benefits of castration, all methods produce pain and distress. Castration by banding is simple, inexpensive, produces fewer complications, and can be performed in a high-throughput manner. Because lidocaine, a local anesthetic, can be delivered to trauma sites topically, we have formulated lidocaine-loaded castration bands (LLBs) to deliver local pain relief to calves during banded castration. The initial lidocaine content of three band types developed was between 80 and 200 mg per band. The transfer kinetics of lidocaine into tissue was determined in vitro, indicating a rapid release for the first 30 min, followed by a slow release lasting at least 48 h. Furthermore, the lidocaine delivery and pain mitigation effects of these LLBs were compared to standard lidocaine injections in vivo. Field studies indicated that LLBs performed at least as well as lidocaine injections for short-term lidocaine delivery into tissues and pain mitigation. Moreover, LLBs significantly outperformed lidocaine injections for long-term delivery and pain mitigation. animals animals animals Development and Field Validation of Lidocaine-Loaded Castration Bands for Bovine Pain Mitigation James W. Saville 1, Joseph A. Ross 2 , Tyler Trefz 1, Crystal Schatz 2, Heather Matheson-Bird 2, Brenda Ralston 3 , Ori Granot 1, Karin Schmid 4, Richard Terry 5, Nicholas D. Allan 2,* , Jeremy E. Wulff1,* and Merle Olson 6 1 Department of Chemistry, University of Victoria, Victoria, BC V8W 3V6, Canada; jameswsaville@gmail.com (J.W.S.); ttrefz@uvic.ca (T.T.); origuvic@gmail.com (O.G.) 1 Department of Chemistry, University of Victoria, Victoria, BC V8W 3V6, Canada; jameswsaville@gmail.com (J.W.S.); ttrefz@uvic.ca (T.T.); origuvic@gmail.com (O.G.) 2 Chinook Contract Research Inc., Airdrie, AB T4A 0C3, Canada; joe.ross@ccr01.com (J.A.R.); crystal.schatz@ccr01.com (C.S.); heather@ccr01.com (H.M.-B.) 3 Alberta Agriculture and Forestry, Airdrie, AB T4A 0C3, Canada; Brenda.Ralston@gov.ab.ca 4 Alberta Beef Producers, Calgary, AB T2E 7H7, Canada; KarinS@albertabeef.org 5 Richard Terry Innovations, LLC, Conyers, GA 30094, USA; rt33@bellsouth.net 6 Alberta Veterinary Laboratories, Calgary, AB T2C 5N6, Canada; merle.olson@avetlabs.com * Correspondence: nick.allan@ccr01.com (N.D.A.); wulff@uvic.ca (J.E.W.) www.mdpi.com/journal/animals Animals 2020, 10, 2363; doi:10.3390/ani10122363 This article was originally published at: https://doi.org/10.3390/ani10122363 Saville, J. W., Ross, J. A., Trefz, T., Schatz, C., Matheson-Bird, H., Ralston, B., … Olson, M. (2020). Development and Field Validation of Lidocaine-Loaded Castration Bands for Bovine Pain Mitigation. Animals, 10(12), 1-16. https://doi.org/10.3390/ani10122363. animals 1. Introduction Castration is one of the most common management procedures performed in the dairy and beef cattle industries. In the United States alone, an estimated 15 million bovine castration procedures are performed each year [1]. In modern agriculture, castration is undertaken to: (i) decrease aggression, enhancing safety for handlers and animals; (ii) selectively control livestock populations; and (iii) produce higher-quality meats that command higher market prices [1–3]. Despite the widely accepted benefits of castration, all methods of castration result in physiological, neuroendocrine, and behavioural changes indicative of distress and pain [1–6]. The Canadian Code of Practice for the Care and Handling of Beef Cattle has recently been updated, advising that pain control be used for castration of bulls older than 6 months, and it is expected that pain management will be advised for all castrations in the near future [7]. Pain management is important for the well-being of the animal and castration recovery time [3,4]. Existing techniques (i.e., ring blocking the scrotum or spermatic cord injection) to deliver anesthesia during castration are not practical at the herd level [7]. Currently, only one pain control product (Meloxicam) is labeled for alleviating the pain associated with castration. This product’s label claim is for up to 56 h of pain relief, requiring approximately 2.5 h to reach maximal plasma concentration [5]; however, given the practicalities of cattle handling, and the desire of producers to mitigate the stress of handling, it is often administered at the time of castration. This means that pain control does not begin until sometime after the initial castration procedure and wears offwell before the wounds have healed. Accordingly, producers, scientists, and agriculture ministries are seeking practical solutions to the challenge of herd-level pain mitigation for castration. Many methods of castration are employed by the cattle industry, each with inherent advantages, disadvantages, and unique considerations. Surgical testicle removal is a common means of castration but is losing popularity [1]. Surgical castration is rapid and effective; however, in certain jurisdictions, a licensed veterinarian may be required on site to perform this procedure [8]. Complications are not uncommon and include hemorrhage, infection, and myiasis. Castration by banding (Figure 1) is an alternative technique and the second-most common method applied [1]. Banded castration takes 3–6 weeks before the testes are sloughed off, making it the slowest means of castration [1,9]. Received: 6 November 2020; Accepted: 8 December 2020; Published: 10 December 2020 The concentrations of lidocaine in the LLB-treated tissue samples were generally in the range of 0.5–3.5 mg of lidocaine per gram of tissue www.mdpi.com/journal/animals Animals 2020, 10, 2363; doi:10.3390/ani10122363 2 of 16 Animals 2020, 10, 2363 and were overall highest after 6 h. Lidocaine-loaded elastration bands deliver therapeutic quantities of lidocaine into scrotal tissues over a period of at least seven days in cattle. This approach would provide long-term pain mitigation to the animals and, by avoiding surgery or the administration of injections, would also decrease the time and handling costs for the producer. Keywords: animal welfare; bovine; castration; elastration; lidocaine; pain mitigation 1. Introduction Although there are fewer complications with banded castration, it produces chronic pain that can last at least 42 days [10]. Additionally, castration band application is simple and may be performed in a high-throughput manner [1,9]. We have therefore focused this study on developing herd-level pain mitigation for banded bovine castrations of different ages and body weights. Local anesthetics are used to numb acute, chronic, and surgical pain across all species. Anesthetics decrease pain sensation by preventing the transmission of nerve impulses from the site of trauma to the brain. Lidocaine is an archetypal local anesthetic, characterized by its rapid onset and prolonged duration of effect [11]. Meléndez et al. (2018) found that injected lidocaine was effective at reducing physiological and behavioural indicators of pain (measured by salivary cortisol, white blood cell counts, scrotal circumference, leg movement, head distance, and escape response) [5]. Additionally, Stafford et al. (2002) showed that lidocaine injected into the scrotum virtually abolished the cortisol response to banded castration [12]. Lidocaine may be effectively delivered to trauma sites non-invasively, through simple topical application [11]. 3 of 16 3 of 17 Animals 2020, 10, 2363 Animals 2020 10 x FOR Figure 1. Castration procedure using elastic castration bands. Figure 1. Castration procedure using elastic castration bands. Figure 1. Castration procedure using elastic castration bands Figure 1. Castration procedure using elastic castration bands. Local anesthetics are used to numb acute, chronic, and surgical pain across all species. Anesthetics decrease pain sensation by preventing the transmission of nerve impulses from the site of trauma to the brain. Lidocaine is an archetypal local anesthetic, characterized by its rapid onset and prolonged duration of effect [11]. Meléndez et al. (2018) found that injected lidocaine was effective at reducing physiological and behavioural indicators of pain (measured by salivary cortisol, white blood cell counts, scrotal circumference, leg movement, head distance, and escape response) [5]. Additionally, Stafford et al. (2002) showed that lidocaine injected into the scrotum virtually abolished the cortisol response to banded castration [12] Lidocaine may be effectively delivered to Motivated by the results available in the literature, we have formulated castration bands containing therapeutic amounts of lidocaine, to deliver local pain relief to calves during banded castration. Based on industry stakeholder inputs, three different sized bands were developed for evaluation and field trialing in staggered parallel development streams to optimize resources and development timelines. medium (beige bands) for b The band material was ma 2. Materials and Methods The band material was made of latex, which is sufficiently permeable to permit the release of local anesthetic from the lumen of the band to exterior surfaces, where it can then penetrate the scrotal tissue. The objective of this study was to evaluate the lidocaine content, tissue transfer, and release kinetics of these lidocaine-loaded bands in vitro. Furthermore, the lidocaine delivery and pain mitigation effects of these lidocaine castration bands were determined in vivo through field trials. Manufacturing and release of lidocaine formulations for each device subtype was evaluated in a matrix-driven design. This development testing also evaluated occupational health and safety considerations, human factors, animal application factors, environmental durability, shelf life, and simulated use case stresses. 2. Materials and Methods Three types of latex elastrator band—small (green), medium (beige), and large (CallicrateTM)— were loaded with free-base lidocaine (no epinephrine) according to a proprietary process that Three types of latex elastrator band—small (green), medium (beige), and large (CallicrateTM)—were loaded with free-base lidocaine (no epinephrine) according to a proprietary process that impregnates lidocaine and a skin permeation enhancer into the material of the band using a solvent carrier to produce LLBs, which were evaluated in this study. The first LLB was developed for small (4.3 cm circumference, 0.5 g) green elastrator bands recommended to be used in calves less than 90 Kg. These small bands had an average of 100 mg of lidocaine per band. The second LLB for the larger beige (5.3 cm circumference, 1.4 g) Tri-bander bands contained an average of 250 mg of lidocaine per band. The CallicrateTM band, recommended for use in animals 180 Kg or greater, is much larger and forms a loop, so only the lower portion of the loop that would be in contact with tissue once applied was loaded with lidocaine. This lidocaine formulation had a blue dye added to help determine where the formulation was placed on the band and had an average of 86.4 mg of lidocaine per gram of band material. Under the conditions of our pilot manufacturing, this was found to be the maximum amount of lidocaine the bands were able to consistently retain. 1. Introduction The size categories include large (CallicrateTM) bands for bulls > 180 Kg, medium (beige bands) for bulls between 90 and 180 Kg, and small (green bands) for calves < 90 Kg. The band material was made of latex, which is sufficiently permeable to permit the release of local anesthetic from the lumen of the band to exterior surfaces, where it can then penetrate the scrotal tissue. abolished the cortisol response to banded castration [12]. Lidocaine may be effectively delivered to trauma sites non-invasively, through simple topical application [11]. Motivated by the results available in the literature, we have formulated castration bands containing therapeutic amounts of lidocaine, to deliver local pain relief to calves during banded castration. Based on industry stakeholder inputs, three different sized bands were developed for evaluation and field trialing in staggered parallel development streams to optimize resources and development timelines. The size categories include large (CallicrateTM) bands for bulls >180 Kg, The objective of this study was to evaluate the lidocaine content, tissue transfer, and release kinetics of these lidocaine-loaded bands in vitro. Furthermore, the lidocaine delivery and pain mitigation effects of these lidocaine castration bands were determined in vivo through field trials. Manufacturing and release of lidocaine formulations for each device subtype was evaluated in a matrix-driven design. This development testing also evaluated occupational health and safety considerations, human factors, animal application factors, environmental durability, shelf life, and simulated use case stresses. ( p p ) impregnates lidocaine and a skin permeation enhancer into the i t d LLB hi h l t d i thi t d T 2.1. In Vitro Measurement of Initial Lidocaine Content in the Bands carrier to produce LLBs, which were evaluated in this study. The first LLB was developed for small (4.3 cm circumference, 0.5 g) green elastrator bands recommended to be used in calves less than 90 Kg. These small bands had an average of 100 mg of lidocaine per band. The second LLB for the larger The lidocaine from several castration bands was extracted in 100 mL tetrahydrofuran (THF) for 2 h at 37 ◦C. The extraction solution was diluted 12.5 times with acetone (in duplicate) and filtered through 4 of 16 Animals 2020, 10, 2363 a 0.2 µm syringe filter prior to injection (in duplicate) onto a gas chromatography–mass spectrometry (GC–MS) instrument (see Table 1 for specifications and run conditions). A standard curve was obtained using solutions of 0.05, 0.1, 0.2, 0.4, 0.8 mg/mL of lidocaine prepared in the same solvent composition as the samples. The standards were injected (in duplicate) onto the same instrument, and the resulting data were used for quantitation. Table 1. GC–MS specifications and run conditions. Table 1. GC–MS specifications and run conditions. Instrument or Parameter Details GC–MS PerkinElmer Clarus 680-AxION iQT Column Elite-5MS, 30 m × 0.25 mm, 0.25 µm Carrier Gas Nitrogen Analysis Time 15 min Flow Rate 1 mL/min Injection Volume 0.5 µL Injection Temperature 250 ◦C Split Ratio 20:1 Oven Program 60 ◦C →300 ◦C over 15 min Detection MS Scan 50—1045 m/z GC–MS PerkinElmer Clarus 680-AxION iQT Column Elite-5MS, 30 m × 0.25 mm, 0.25 µm 2.2. In Vitro Measurement of Lidocaine Transfer into Steak Tissue over Time Table 1. GC–MS specifications and run conditions. Instrument or Parameter Details GC–MS PerkinElmer Clarus 680-AxION iQT Column Elite-5MS, 30 m × 0.25 mm, 0.25 µm Carrier Gas Nitrogen Analysis Time 15 min Flow Rate 1 mL/min Injection Volume 0.5 µL Injection Temperature 250 ◦C Split Ratio 20:1 Oven Program 60 ◦C →300 ◦C over 15 min Detection MS Scan 50—1045 m/z GC–MS PerkinElmer Clarus 680-AxION iQT Column Elite-5MS, 30 m × 0.25 mm, 0.25 µm 2.2. In Vitro Measurement of Lidocaine Transfer into Steak Tissue over Time 2.2. 2.3. Field Study Overview The protocols were reviewed and approved by Chinook Contract Research’s Institutional Animal Care and Use Committee (OLAW #F19-00433, Application #14026-002-2,3,7) and the animals were cared for in accordance with Canadian Council on Animal Care (CACC) guidelines [13]. We developed and conducted a series of field studies to evaluate lidocaine release kinetics and pain mitigation effects in vivo for each band type. The three studies reported here first examined the green bands in May 2018, then the beige bands in July 2018, followed by the CallicrateTM bands in October 2018. Each study was conducted at the same commercial veal operation and feedlot in southern Alberta. For each study, animals were weighed, ranked by weight, and allocated to treatment (LLB) or control (lidocaine injection) groups using random numbers. The animal was the experimental unit. All calves were intact male Holstein calves which were brought to the facility from multiple dairy farms in Southern Alberta. For study number 1 (green band) or 2 (beige band): Forty-eight calves (each study), weaned at birth and 3–4 weeks of age (53 ± 4.0 kg of body weight for study 1, 56.0 ± 8.0 kg of body weight for study 2), were used in an 8 day trial. Upon arrival at the farm (at approximately 4–5 days of age), calves were placed into individual pens (2.1 m × 0.76 m) with a partially slatted floor for waste removal. All animals were housed in the same room of a barn with forced air ventilation. Calves were vaccinated with an 8-way clostridial vaccine (Tasvax 8, Merck Animal Health, Kirkland, QC, Canada), respiratory disease vaccine (Inforce 3, Intranasal vaccine Zoetis Canada Inc., Kirkland, QC, Canada), topical parasiticide (Solmectin Pour-On for Cattle, Alberta Veterinary Laboratories Ltd., Calgary, AB, Canada), and allowed a minimum of two week adaptation period prior to the start of the trial. Calves were fed twice daily (morning and afternoon) via 7.6 L buckets attached to the front gate of each calf’s individual pen. One bucket contained milk replacer, 5 L per day (Mapleview Express Start + Deccox, Mapleview Agri Ltd., Drayton, ON, Canada) and the second bucket a dry pelleted complete feed (21% Protein Calf Starter, Landmark Feeds, Strathmore, AB, Canada). On the days of castration, biopsy, and biometrics collection, calves were manually restrained within their individual pen by a staffmember utilizing proper restraining methods for young calves. ( p p ) impregnates lidocaine and a skin permeation enhancer into the i t d LLB hi h l t d i thi t d T 2.1. In Vitro Measurement of Initial Lidocaine Content in the Bands In Vitro Measurement of Lidocaine Transfer into Steak Tissue over Time The transfer kinetics of lidocaine into steak tissue (shown schematically in Figure 2) was determined for the small green bands as follows: A bovine sterling silver inside round steak was cut into 1 cm3 portions, and a LLB was placed around the steak and incubated for 0, 0.5, 5, 24, and 48 h at 37 ◦C, 5% CO2 (in triplicate for each time point). The LLB was removed from the steak cube following the prescribed incubation time, and both band and steak were stored in separate sealed containers at 4 ◦C. Steak cubes were cut into 10 uniformly sized pieces and extracted (twice) with 100 mL THF for 2 h at 37 ◦C. The extraction solution was diluted 2 times with acetone and filtered through a 0.2 µm syringe filter prior to injection (in duplicate) onto a GC–MS instrument. The LLBs from each time point were also extracted (three times) in 100 mL THF, and the extraction solution was diluted and analyzed as described above. Animals 2020, 10, x FOR PEER REVIEW 5 of 17 Figure 2. Schematic overview of lidocaine quantitation in steak tissue. Figure 2. Schematic overview of lidocaine quantitation in steak tissue. Figure 2. Schematic overview of lidocaine quantitation in steak tissue. Figure 2. Schematic overview of lidocaine quantitation in steak tissue. 5 of 16 Animals 2020, 10, 2363 2.4.1. Infrared Imaging of Scrotal Temperature Images of the scrotal neck were captured above and below the placement of the elastration band using a thermal imaging camera (Model E75 1.1, lense 42◦; FLIR Systems, Made in Estonia and Distributed by ITM Instruments Inc., Calgary, AB, Canada) from a distance of approximately 1 m (Emissivity = 0.95). The temperatures were registered and recorded at a single point (indicated by cross hairs in the thermographs) of the target scrotal areas approximately 2 cm above or below the castration band for each band type. Temperatures were also measured for the under belly of the animal, with the center of the scrotum targeted (beige and CallicrateTM bands only; under belly temperatures were only considered and introduced at the conclusion of the green band field trial). Note also that the timing of the temperature measurements was updated between the green band trial (1, 1.5, 24, 48, and 144 h) and the later field trials (2, 6, 24, 48, and 168 h). 2.4. Measuring Lidocaine Release Kinetics and Pain-Associated Behaviour In Vivo The amount of lidocaine was determined from two tissue biopsies taken at each time point (2, 6, 24, 48, and 168 h after band placement) to determine in vivo lidocaine release rates. After removing the bands, two tissue biopsy samples (punch biopsy comprising both skin and subcutaneous tissue, 4 mm) were collected from the area that was in direct contact with the band. Each biopsy sample was placed in a microtube and stored at −80 ◦C. Tissue lidocaine extraction was initiated by chemically homogenizing the skin and subcutaneous tissue with 1 M Sodium Hydroxide and then neutralizing the dissolved solution with hydrochloric acid. A liquid–liquid extraction was performed with ethyl ether to separate and allow the removal of the organic layer. The remaining ether-lidocaine solution was evaporated to dryness and the residue re-dissolved with 1 mL of high-performance liquid chromatography (HPLC)-grade methyl alcohol. Lidocaine concentrations were measured by HPLC to determine lidocaine release (see Table 2 for specifications and run conditions). Table 2. HPLC specifications and run conditions. Instrument or Parameter Details HPLC Hewlett Packard 1100 Series Column Kinetex 2.6 µm C18 (100A, 150 × 4.6 mm) Mobile Phase 40:60 (Acetonitrile: 0.05 M Sodium Phosphate Buffer Solution), 0.05% Diethylamine Analysis Time 6 min Flow Rate 1 mL/min Injection Volume 10 µL Column Temperature 28 ◦C Detector Variable Wavelength Detector (VWD) Wavelength 210 nm Bandwidth 10 nm Table 2. HPLC specifications and run conditions. Table 2. HPLC specifications and run conditions. At each time point, prior to punch biopsies, the animals were monitored for inflammation and pain-associated behaviour as follows: 2.3. Field Study Overview 2.4. Measuring Lidocaine Release Kinetics and Pain-Associated Behaviour In Vivo 2.4. Measuring Lidocaine Release Kinetics and Pain-Associated Behaviour In Vivo 2.3. Field Study Overview For study number 3 (CallicrateTM band): Thirty calves, weaned at birth and 5 months of age (225 ± 20.0 kg of body weight), were used in an 8 day trial. Calves were comingled in a rectangular open-air pen (37 m × 55 m) with a wind break fence, a feed bunk along the front of the pen, straw bedding, and ad libitum well water supplied via an automatic watering system. Calves were vaccinated with an 8-way clostridial vaccine (Tasvax, Merck Animal Health, Kirkland, QC, Canada), respiratory disease vaccine (Inforce 3, Intranasal vaccine Zoetis Canada Inc., Kirkland, QC, Canada), and topical parasiticide (Solmectin Pour-On for Cattle, Alberta Veterinary Laboratories Ltd., Calgary, AB, Canada) at 1–2 weeks of age, and an 8-way clostridial vaccine again at castration. Calves also received an implant at Castration (Component E-S, Elanco Animal Health, Guelph, ON, Canada). Calves were adapted on farm for a minimum of four months prior to the start of the trial. Calves were fed once daily, approximately 3.5% of their body weight: 7.7–8.2 kg total mixed ration (TMR) comprising 30% barley silage, 15% corn dried distillers grain, 2.5% Premix containing mineral and vitamins (Landmark Feeds, Strathmore, AB, Canada), and 52.5% barley grain. On the days of castration, biopsy, and biometrics collection, calves were restrained in a manual squeeze chute (Lakeland, Stonewall, MB, Canada). Animals in each study were randomly assigned to either experimental group 1 (control: lidocaine injection and castration with plain castration band) or 2 (treatment: castration using lidocaine-loaded band). Each experimental group contained 5 sampling time points (2, 6, 24, 48, and 168 h post-elastration), yielding 3 animals per treatment per time point (n = 3 per treatment per time point). A 20 mg/mL solution of lidocaine hydrochloride with 0.01 mg/mL epinephrine [5] (LIDO-2, Rafter 8 products, Calgary, AB, Canada; 1 mL for the Green- or Beige-banded small calves, 3 mL for the CallicrateTM-banded, larger calves) was injected subcutaneously into each of the spermatic cords in the neck of the scrotum of control animals before application of the plain castration band. LLBs and plain castration bands were administered to the treatment and control groups, respectively, at t = 0 h. All of Animals 2020, 10, 2363 6 of 16 the animals were weighed individually using a Jorvet scale (model J825PM, Jorgensen Laboratories, CO, USA) on day 0 and day 7 to calculate an average daily gain (ADG) for each experimental condition. 3.1. Transfer Kinetics for Lidocaine-Loaded Castration Bands (LLBs) In Vitro GC–MS was employed to measure lidocaine concentrations in vitro (shown schematically in Figure 2). The amount of lidocaine in the LLBs was quantified by comparison to a standard curve (Figure 3A), indicating an initial content of approximately 80–210 mg of lidocaine per band (Figure 3B) for the three different LLBs developed. As an initial proof of concept, the transfer kinetics of lidocaine into ex vivo tissue (steak) was determined for the small green castration bands (Figure 4). The amount of lidocaine released from the bands was rapid for the first 30 min, followed by a slower release lasting at least 48 h (Figure 4A). Similarly, the amount of lidocaine transferred into the tissue was initially rapid, reaching approximately 7 mg in the first 30 min before plateauing at approximately 13.5 mg at 5 h, which was sustained for at least 48 h after band placement (Figure 4B). Taken together, these data suggest that LLBs are capable of delivering significant concentrations of lidocaine into tissue for at least 48 h. Animals 2020, 10, x FOR PEER REVIEW 8 of 17 Figure 3. Calibration curve and lidocaine quantitation by GC–MS. (A) Standard curve for various lidocaine concentrations quantified (in duplicate) by GC–MS. (B) Quantitation of lidocaine extracted from each type of lidocaine-loaded castration band (LLB). Note that, for the Callicrate bands, only a section of the band (corresponding with the surface that would contact the animal’s scrotum) was analyzed. Bars represent the mean ± standard deviation for 6 (green), 3 (beige), or 4 (Callicrate) independent replicates. Figure 3. Calibration curve and lidocaine quantitation by GC–MS. (A) Standard curve for various lidocaine concentrations quantified (in duplicate) by GC–MS. (B) Quantitation of lidocaine extracted from each type of lidocaine-loaded castration band (LLB). Note that, for the Callicrate bands, only a section of the band (corresponding with the surface that would contact the animal’s scrotum) was analyzed. Bars represent the mean ± standard deviation for 6 (green), 3 (beige), or 4 (Callicrate) independent replicates. Figure 3. Calibration curve and lidocaine quantitation by GC–MS. (A) Standard curve for various lidocaine concentrations quantified (in duplicate) by GC–MS. (B) Quantitation of lidocaine extracted from each type of lidocaine-loaded castration band (LLB). Note that, for the Callicrate bands, only a section of the band (corresponding with the surface that would contact the animal’s scrotum) was analyzed. 2.5. Statistical Analyses Statistical significance was determined using an unpaired, two-tailed t-test. Data were assessed for normality using a Shapiro–Wilk test. The cutofffor significance was p < 0.05. The experimental unit was defined as each individual animal. Statistical analyses were carried out in Prism v 8.4.3 (GraphPad Software, San Diego, CA, USA). 2.4.2. Electrostimulation After infrared imaging, cutaneous stimulation was performed according to the procedure of Fierheller et al. [14] for the beige and CallicrateTM banded experimental groups. This procedure was not performed for the animals castrated with green bands, as the evaluation methodology was not developed at the time of the green band field trial. A peripheral variable output nerve stimulator with the provided extension lead wires (one positive and one negative) and infant monitoring electrodes (8-1053-60; SunStim Peripheral Nerve Stimulator; Distributed by SunMed, Largo, FL, USA) was 7 of 16 Animals 2020, 10, 2363 used to stimulate the skin over the banded area of the calf’s scrotum (after removing the band). Measurements were made at t = 2, 6, 24, 48, 168 h post-elastration. The uniformly effective stimulus setting was established to be 90 mAmp. The response of the animals to electrostimulation was graded [14] by a blinded large-animal veterinarian, using the following scale: 0 = no reaction, 1 = slight reaction (e.g., muscle tightening, twitch in the hind area, stiffening of stance), 2 = moderate reaction (e.g., flinch, slight jump with hind, tightening and stiffer stance), and 3 = severe reaction (e.g., severe flinch, obvious jump, abrupt stiffening). Reactions (if any) were immediate. 3.1. Transfer Kinetics for Lidocaine-Loaded Castration Bands (LLBs) In Vitro Lidocaine transfer kinetics between lidocaine-loaded, green castration bands and steak tissue Figure 4. Lidocaine transfer kinetics between lidocaine-loaded, green castration bands and steak tissue. (A) The amount of lidocaine recovered from lidocaine-loaded green castration bands (LLBs) following various periods of incubation wrapped around steak tissue. (B) The amount of lidocaine extracted from steak tissue following various incubation periods wrapped with LLBs. Lidocaine was quantified by GC–MS. Bars represent the mean ± standard deviation for three independent replicates. Figure 4. Lidocaine transfer kinetics between lidocaine-loaded, green castration bands and steak tissue. (A) The amount of lidocaine recovered from lidocaine-loaded green castration bands (LLBs) following various periods of incubation wrapped around steak tissue. (B) The amount of lidocaine extracted from steak tissue following various incubation periods wrapped with LLBs. Lidocaine was quantified by GC–MS. Bars represent the mean ± standard deviation for three independent replicates. 3.2. LLBs Deliver Therapeutic Quantities of Lidocaine into Scrotal Tissue In Vivo In order to confirm the efficacy of LLBs for lidocaine delivery into scrotal tissue during band castration, three field studies were performed to evaluate lidocaine release kinetics and pain mitigation effects in vivo. For each of the three band types (green, beige, and CallicrateTM), animals were castrated with either LLBs or with plain bands; the latter (control) group were injected with lidocaine immediately prior to band application for pain mitigation (in compliance with Institutional Animal Use and Care Committee recommendations). Scrotal tissue from the banding site was sampled, and the concentration of lidocaine therein was measured by HPLC over the course of a one-week study period (Figure 5). For the green bands (small calf bands for bulls < 90 Kg), LLBs generally delivered quantities of lidocaine that were similar to those of the lidocaine-injected control samples, although the 24 h tissue sample contained significantly more lidocaine in the LLB group than in the injected group (Figure 5A). In the case of the beige bands (medium bands for bulls < 180 Kg), LLBs generally delivered higher lidocaine concentrations relative to the injected controls, with statistically significant increases at 6, 24, and 168 h (Figure 5B). Similarly, LLB-treated tissue samples generally contained more lidocaine than their injected counterparts for CallicrateTM bands (large bands for bulls > 180 Kg), with significant differences at all but the 2 and 24 h time points (Figure 5C). 3.1. Transfer Kinetics for Lidocaine-Loaded Castration Bands (LLBs) In Vitro Bars represent the mean ± standard deviation for 6 (green), 3 (beige), or 4 (Callicrate) independent replicates. Figure 3. Calibration curve and lidocaine quantitation by GC–MS. (A) Standard curve for various lidocaine concentrations quantified (in duplicate) by GC–MS. (B) Quantitation of lidocaine extracted from each type of lidocaine-loaded castration band (LLB). Note that, for the Callicrate bands, only a section of the band (corresponding with the surface that would contact the animal’s scrotum) was analyzed. Bars represent the mean ± standard deviation for 6 (green), 3 (beige), or 4 (Callicrate) independent replicates. 8 of 16 te) Animals 2020, 10, 2363 analyzed. Bars independent re Figure 4. Lidocaine transfer kinetics between lidocaine-loaded, green castration bands and steak tissue. (A) The amount of lidocaine recovered from lidocaine-loaded green castration bands (LLBs) following various periods of incubation wrapped around steak tissue. (B) The amount of lidocaine extracted from steak tissue following various incubation periods wrapped with LLBs. Lidocaine was quantified by GC–MS. Bars represent the mean ± standard deviation for three independent replicates. Figure 4. Lidocaine transfer kinetics between lidocaine-loaded, green castration bands and steak tissue. (A) The amount of lidocaine recovered from lidocaine-loaded green castration bands (LLBs) following various periods of incubation wrapped around steak tissue. (B) The amount of lidocaine extracted from steak tissue following various incubation periods wrapped with LLBs. Lidocaine was quantified by GC–MS. Bars represent the mean ± standard deviation for three independent replicates. LLB D li Th i Q i i f Lid i i S l Ti I Vi Figure 4. Lidocaine transfer kinetics between lidocaine-loaded, green castration bands and steak tissue. (A) The amount of lidocaine recovered from lidocaine-loaded green castration bands (LLBs) following various periods of incubation wrapped around steak tissue. (B) The amount of lidocaine extracted from steak tissue following various incubation periods wrapped with LLBs. Lidocaine was quantified by GC–MS. Bars represent the mean ± standard deviation for three independent replicates. Figure 4. Lidocaine transfer kinetics between lidocaine-loaded, green castration bands and steak tissue. (A) The amount of lidocaine recovered from lidocaine-loaded green castration bands (LLBs) following various periods of incubation wrapped around steak tissue. (B) The amount of lidocaine extracted from steak tissue following various incubation periods wrapped with LLBs. Lidocaine was quantified by GC–MS. Bars represent the mean ± standard deviation for three independent replicates. Figure 4. Lidocaine transfer kinetics between lidocaine-loaded, green castration bands and steak Figure 4. 3.1. Transfer Kinetics for Lidocaine-Loaded Castration Bands (LLBs) In Vitro The concentrations of lidocaine in the LLB-treated tissue samples were generally in the range of 0.5–3.5 mg of lidocaine per gram of tissue and were generally highest after 6 h (Figure 5). Taken together, the results indicate that, over the short term, LLBs deliver at least as much lidocaine into scrotal tissue as injections into the spermatic cords. Over the long term (i.e., upwards of 6 h), LLBs can deliver significantly higher levels of lidocaine than injections. 9 of 16 deliver Animals 2020, 10, 2363 as injections into t significantly highe Figure 5. Lidocaine concentrations from scrotal biopsy samples collected over time. Time indicates the duration the band was on the animal prior to biopsy. Biopsies from animals treated with green Figure 5. Lidocaine concentrations from scrotal biopsy samples collected over time. Time indicates the duration the band was on the animal prior to biopsy. Biopsies from animals treated with green (A), beige (B), or CallicrateTM (C) bands (LLB), or their corresponding controls (lidocaine injection), were homogenized, extracted, and the lidocaine content measured by HPLC. Bars represent the mean ± standard error of the mean (SEM) for three independent replicates per time point. Figure 5. Lidocaine concentrations from scrotal biopsy samples collected over time. Time indicates the duration the band was on the animal prior to biopsy. Biopsies from animals treated with green Figure 5. Lidocaine concentrations from scrotal biopsy samples collected over time. Time indicates the duration the band was on the animal prior to biopsy. Biopsies from animals treated with green (A), beige (B), or CallicrateTM (C) bands (LLB), or their corresponding controls (lidocaine injection), were homogenized, extracted, and the lidocaine content measured by HPLC. Bars represent the mean ± standard error of the mean (SEM) for three independent replicates per time point. Figure 5. Lidocaine concentrations from scrotal biopsy samples collected over time. Time indicates the duration the band was on the animal prior to biopsy. Biopsies from animals treated with green Figure 5. Lidocaine concentrations from scrotal biopsy samples collected over time. Time indicates the duration the band was on the animal prior to biopsy. Biopsies from animals treated with green (A), beige (B), or CallicrateTM (C) bands (LLB), or their corresponding controls (lidocaine injection), were homogenized, extracted, and the lidocaine content measured by HPLC. Bars represent the mean ± standard error of the mean (SEM) for three independent replicates per time point. 3.1. Transfer Kinetics for Lidocaine-Loaded Castration Bands (LLBs) In Vitro As an indicator of overall performance, the animals were weighed on induction to this study (day 0) and on day 7 to calculate an average daily gain (ADG) for each experimental condition. ADG was comparable for LLB-treated versus lidocaine-injected animals, indicating similar performance between these groups (Table 3). No statistically significant differences in ADG were observed between the LLB-treated and injected animals (statistical significance was determined using an unpaired, two-tailed t-Test). Infrared thermography is a non-invasive means of measuring tissue inflammation [15,16]. Accordingly, we used thermal imaging to assess the temperature of different scrotal regions, and representative images are presented in Figure 6, with the results quantitated in Figure 7. As expected, scrotal temperatures were generally lower below the banding site over time, consistent with the restriction of blood flow imposed by the bands (Figure 7). No significant differences in scrotal temperature were observed for LLBs relative to their injected counterparts, indicating similar levels of inflammation (Figure 7). However, at 168 h, the under-belly temperature was significantly lower for CallicrateTM LLBs relative to their injected controls, suggesting decreased inflammation for the LLB-treated animals at this time point (Figure 7C). The number of tail flicks and average heart rate were also measured, and indicated no significant differences between LLB-treated and lidocaine-injected animals (Supplemental Figures S1 and S2). 10 of 16 Animals 2020, 10, 2363 Table 3. Average daily gain for control versus treatment animals. Average Animal Size at Banding Band Type Treatment Group ADG a (Kg/Day) ± SD b 225 ± 20 Kg CallicrateTM Injection (n = 14) 0.43 0.52 LLB (n = 15) 0.80 0.67 56 ± 8 Kg Beige Injection (n = 21) 0.93 0.33 LLB (n = 20) 0.99 0.23 53 ± 4 Kg Green Injection (n = 3) 0.73 0.27 LLB (n = 3) 0.89 0.65 a ADG: average daily gain, calculated 7 days post-castration. b SD: standard deviation. nimals 2020, 10, x FOR PEER REVIEW 11 of 17 Figure 6. Infrared imaging of animals with castration bands. Representative infrared images (left) and corresponding photographs (right) are presented for (A) above the castration band, (B) below the band, and (C) the underbelly of the animal. Cross hairs (left-most images) indicate the point at which the temperature was registered. Orange arrows (right-most images) indicate the bands. The temperatures were quantitated and are presented in Figure 7. Figure 6. Infrared imaging of animals with castration bands. 3.1. Transfer Kinetics for Lidocaine-Loaded Castration Bands (LLBs) In Vitro Representative infrared images (left) and corresponding photographs (right) are presented for (A) above the castration band, (B) below the band, and (C) the underbelly of the animal. Cross hairs (left-most images) indicate the point at which the temperature was registered. Orange arrows (right-most images) indicate the bands. The temperatures were quantitated and are presented in Figure 7. Figure 6. Infrared imaging of animals with castration bands. Representative infrared images (left) and corresponding photographs (right) are presented for (A) above the castration band, (B) below the band, and (C) the underbelly of the animal. Cross hairs (left-most images) indicate the point at which the temperature was registered. Orange arrows (right-most images) indicate the bands. The temperatures were quantitated and are presented in Figure 7. Figure 6. Infrared imaging of animals with castration bands. Representative infrared images (left) and corresponding photographs (right) are presented for (A) above the castration band, (B) below the band, and (C) the underbelly of the animal. Cross hairs (left-most images) indicate the point at which the temperature was registered. Orange arrows (right-most images) indicate the bands. The temperatures were quantitated and are presented in Figure 7. Figure 6. Infrared imaging of animals with castration bands. Representative infrared images (left) and corresponding photographs (right) are presented for (A) above the castration band, (B) below the band, and (C) the underbelly of the animal. Cross hairs (left-most images) indicate the point at which the temperature was registered. Orange arrows (right-most images) indicate the bands. The temperatures were quantitated and are presented in Figure 7. Figure 6. Infrared imaging of animals with castration bands. Representative infrared images (left) and corresponding photographs (right) are presented for (A) above the castration band, (B) below the band, and (C) the underbelly of the animal. Cross hairs (left-most images) indicate the point at which the temperature was registered. Orange arrows (right-most images) indicate the bands. The temperatures were quantitated and are presented in Figure 7. Figure 6. Infrared imaging of animals with castration bands. Representative infrared images (left) and corresponding photographs (right) are presented for (A) above the castration band, (B) below the band, and (C) the underbelly of the animal. Cross hairs (left-most images) indicate the point at which the temperature was registered. Orange arrows (right-most images) indicate the bands. The temperatures were quantitated and are presented in Figure 7. Figure 6. Infrared imaging of animals with castration bands. 3.1. Transfer Kinetics for Lidocaine-Loaded Castration Bands (LLBs) In Vitro Representative infrared images (left) and corresponding photographs (right) are presented for (A) above the castration band, (B) below the band, and (C) the underbelly of the animal. Cross hairs (left-most images) indicate the point at which the temperature was registered. Orange arrows (right-most images) indicate the bands. The temperatures were quantitated and are presented in Figure 7. 11 of 16 12 of 17 Animals 2020, 10, 2363 Animals 2020 10 x FOR Figure 7. Scrotal temperatures of control and treatment calves above and below castration band placement over time. Scrotal temperature above and below the green (A), beige (B), and CallicrateTM (C) castration bands were plotted against the duration of band placement for test (LLB) and control (injection) animals. The temperature of the animal’s belly was also measured for the animals treated with beige (B) and CallicrateTM (C) bands. Bars represent the mean ± standard error of the mean (SEM) for three independent replicates per time point. Statistical significance was determined using an unpaired, two-tailed t-test. Data were assessed for normality using a Shapiro–Wilk test. The cutoff for significance was p < 0.05. Figure 7. Scrotal temperatures of control and treatment calves above and below castration band placement over time. Scrotal temperature above and below the green (A), beige (B), and CallicrateTM (C) castration bands were plotted against the duration of band placement for test (LLB) and control (injection) animals. The temperature of the animal’s belly was also measured for the animals treated with beige (B) and CallicrateTM (C) bands. Bars represent the mean ± standard error of the mean (SEM) for three independent replicates per time point. Statistical significance was determined using an unpaired, two-tailed t-test. Data were assessed for normality using a Shapiro–Wilk test. The cutofffor significance was p < 0.05. Fi ll f t l b t th t ti it l t ti l ti d Figure 7 Scrotal temperatures of control and treatment calves above and below castration band Figure 7. Scrotal temperatures of control and treatment calves above and below castration band Figure 7. Scrotal temperatures of control and treatment calves above and below castration band placement over time. Scrotal temperature above and below the green (A), beige (B), and CallicrateTM (C) castration bands were plotted against the duration of band placement for test (LLB) and control (injection) animals. 3.1. Transfer Kinetics for Lidocaine-Loaded Castration Bands (LLBs) In Vitro The temperature of the animal’s belly was also measured for the animals treated with beige (B) and CallicrateTM (C) bands. Bars represent the mean ± standard error of the mean (SEM) for three independent replicates per time point. Statistical significance was determined using an unpaired, two-tailed t-test. Data were assessed for normality using a Shapiro–Wilk test. The cutoff for significance was p < 0 05 Figure 7. Scrotal temperatures of control and treatment calves above and below castration band placement over time. Scrotal temperature above and below the green (A), beige (B), and CallicrateTM (C) castration bands were plotted against the duration of band placement for test (LLB) and control (injection) animals. The temperature of the animal’s belly was also measured for the animals treated with beige (B) and CallicrateTM (C) bands. Bars represent the mean ± standard error of the mean (SEM) for three independent replicates per time point. Statistical significance was determined using an unpaired, two-tailed t-test. Data were assessed for normality using a Shapiro–Wilk test. The cutofffor significance was p < 0.05. Finally, as a measure of scrotal numbness at the castration sites, electrostimulation was used to elicit a pain response, which was graded according to the scale detailed in Materials and Methods. For both the beige and CallicrateTM bands, LLBs gave comparable pain responses to their injected controls up to 48 h (Figure 8). However, at 168 h, LLBs gave significantly decreased pain responses relative to the injected controls, indicating that LLBs are more effective at inducing long-term numbness in the relevant tissue (Figure 8) Finally, as a measure of scrotal numbness at the castration sites, electrostimulation was used to elicit a pain response, which was graded according to the scale detailed in Materials and Methods. For both the beige and CallicrateTM bands, LLBs gave comparable pain responses to their injected controls up to 48 h (Figure 8). However, at 168 h, LLBs gave significantly decreased pain responses relative to the injected controls, indicating that LLBs are more effective at inducing long-term numbness in the relevant tissue (Figure 8). 12 of 16 13 of 17 Animals 2020, 10, 2363 Animals 2020, 10, x FOR Figure 8. Response of control and treatment calves to electrostimulation at the castration site. Animals were treated with electrostimulation at the banding site and their pain response measured according to a graded scale as described in Materials and Methods. 4. Discussion 4. Discussion The main goal of this study was to establish whether lidocaine could be topically delivered from elastration bands into tissue for pain mitigation during banded castration. As an initial proof of concept, the transfer kinetics of lidocaine into ex vivo tissue (steak) was successfully determined. These data suggest that lidocaine delivery by LLBs into tissue is initially fast, followed by a sustained delivery lasting at least 48 h (Figure 4). Similar results were obtained in a study that evaluated lidocaine permeation across rabbit ear skin from a transdermal patch [17]. We note that the transfer kinetics of lidocaine into steak tissue was only determined for the small green bands; given the conserved latex composition of the three different band types and the similar amount of lidocaine in each band (Figure 3), it is reasonable to expect similar results for both the beige and CallicrateTM bands. We acknowledge that steak and scrotal tissue have different characteristics that could affect lidocaine release and diffusion. Accordingly, we have moved future in vitro lidocaine transfer experiments into tissue models incorporating epidermal and dermal tissues to better replicate bovine scrotal tissue. However, at the inception of this study, these tissue models were not yet in place and therefore steak tissue was used to provide a rough approximation of lidocaine transfer kinetics prior The main goal of this study was to establish whether lidocaine could be topically delivered from elastration bands into tissue for pain mitigation during banded castration. As an initial proof of concept, the transfer kinetics of lidocaine into ex vivo tissue (steak) was successfully determined. These data suggest that lidocaine delivery by LLBs into tissue is initially fast, followed by a sustained delivery lasting at least 48 h (Figure 4). Similar results were obtained in a study that evaluated lidocaine permeation across rabbit ear skin from a transdermal patch [17]. We note that the transfer kinetics of lidocaine into steak tissue was only determined for the small green bands; given the conserved latex composition of the three different band types and the similar amount of lidocaine in each band (Figure 3), it is reasonable to expect similar results for both the beige and CallicrateTM bands. We acknowledge that steak and scrotal tissue have different characteristics that could affect lidocaine release and diffusion. 3.1. Transfer Kinetics for Lidocaine-Loaded Castration Bands (LLBs) In Vitro Graded responses for the beige (A) and CallicrateTM (B) bands were plotted against the duration of band placement for test (LLB) and control (injection) animals. Bars represent the mean ± standard error of the mean (SEM) for three independent replicates per time point. Statistical significance was determined using an unpaired, two-tailed t-test. Data were assessed for normality using a Shapiro–Wilk test. The cutoff for significance was p < 0.05. Figure 8. Response of control and treatment calves to electrostimulation at the castration site. Animals were treated with electrostimulation at the banding site and their pain response measured according to a graded scale as described in Materials and Methods. Graded responses for the beige (A) and CallicrateTM (B) bands were plotted against the duration of band placement for test (LLB) and control (injection) animals. Bars represent the mean ± standard error of the mean (SEM) for three independent replicates per time point. Statistical significance was determined using an unpaired, two-tailed t-test. Data were assessed for normality using a Shapiro–Wilk test. The cutofffor significance was p < 0.05. Figure 8. Response of control and treatment calves to electrostimulation at the castration site. Animals were treated with electrostimulation at the banding site and their pain response measured according to a graded scale as described in Materials and Methods. Graded responses for the beige (A) and CallicrateTM (B) bands were plotted against the duration of band placement for test (LLB) and control (injection) animals. Bars represent the mean ± standard error of the mean (SEM) for three independent replicates per time point. Statistical significance was determined using an unpaired, two-tailed t-test. Data were assessed for normality using a Shapiro–Wilk test. The cutoff for significance was p < 0.05. Figure 8. Response of control and treatment calves to electrostimulation at the castration site. Animals were treated with electrostimulation at the banding site and their pain response measured according to a graded scale as described in Materials and Methods. Graded responses for the beige (A) and CallicrateTM (B) bands were plotted against the duration of band placement for test (LLB) and control (injection) animals. Bars represent the mean ± standard error of the mean (SEM) for three independent replicates per time point. Statistical significance was determined using an unpaired, two-tailed t-test. Data were assessed for normality using a Shapiro–Wilk test. The cutofffor significance was p < 0.05. 4. Discussion 4. Discussion Accordingly, we have moved future in vitro lidocaine transfer experiments into tissue models incorporating epidermal and dermal tissues to better replicate bovine scrotal tissue. However, at the inception of this study, these tissue models were not yet in place and therefore steak tissue was used to provide a rough approximation of lidocaine transfer kinetics prior to field studies. therefore steak tissue was used to provide a rough approximation of lidocaine transfer kinetics prior to field studies. The in vitro observations were generally corroborated by the in vivo data (in which all three band types were assessed): tissue concentrations of lidocaine were similar over the short term (i.e., up to 6 h), but higher over the longer term (i.e., up to 7 days) for LLBs relative to injected control animals (Figure 5). These results confirm that lidocaine absorption is initially similar for the two routes of administration (i.e., transdermal vs subcutaneous injection), despite the difference between The in vitro observations were generally corroborated by the in vivo data (in which all three band types were assessed): tissue concentrations of lidocaine were similar over the short term (i.e., up to 6 h), but higher over the longer term (i.e., up to 7 days) for LLBs relative to injected control animals (Figure 5). These results confirm that lidocaine absorption is initially similar for the two routes of administration (i.e., transdermal vs subcutaneous injection), despite the difference between the two tissue types. However, lidocaine tends to be significantly higher in LLB-treated vs injected samples 13 of 16 Animals 2020, 10, 2363 13 of 16 starting at approximately the 6 h time point, likely reflecting the fact that lidocaine injection is a one-offtreatment at Time 0, while LLBs were shown continue to deliver lidocaine for at least 7 days. This would have obvious benefits for both acute and chronic pain management during castration, with immediate pain relief at the time of band application and sustained pain-relief over the course of at least 7 days. In order to confirm whether LLBs continue to deliver therapeutic quantities of lidocaine beyond 7 days, it will be necessary to conduct a longer-term study. The concentrations of lidocaine in the LLB-treated tissue samples were generally in the range of 0.15–3.5 mg of lidocaine per gram of tissue. 4. Discussion 4. Discussion In contrast, lidocaine levels were generally lower for injected tissue samples—in fact, beyond the 6 h time point, they were generally either undetectable or around 0.1 mg of lidocaine per gram of tissue (100 µg/g of tissue). For reference, tissue concentrations below 100 µg/g are not considered therapeutic [18]. It thus appears that lidocaine injection is often—but not always—sufficient to achieve therapeutic levels of lidocaine in the scrotal tissue, while LLBs consistently yield levels well above this threshold. Accordingly, with regard to the performance metrics evaluated in this study, LLBs often perform similarly to lidocaine injection. For instance, LLBs yielded no statistically significant differences in ADG versus lidocaine injection (Table 3), suggesting that LLB-treated animals gained at least as much weight as the lidocaine-injected animals. ADG is a common indicator for post-operative performance in livestock [19–21]. The lack of statistically significant differences in ADG could also reflect the high variability in this data due, at least in part, to the low n value (especially for the green bands). The green-banded ADG sampling is especially low (n = 3) because measuring ADG was only considered and introduced at the conclusion of the green band trial. Based on this pilot work, it would be interesting to measure ADG in a future trial involving a larger number of animals. Additionally, scrotal and underbelly temperatures were generally similar for LLB-treated versus injected animals according to infrared thermography (Figures 6 and 7), with only one statistically significant difference: for Callicrate™bands, at 168 h, the under-belly temperature was significantly lower for LLB-treated vs injected animals (Figure 7C). In this context, lower temperature indicates reduced blood flow and/or decreased inflammation [15,16]. This difference might reflect the fact that lidocaine levels were significantly higher in the LLB-treated tissues at this time point; in fact, lidocaine was undetectable in the injected samples (Figure 5C). Finally, LLB-treated animals had similar responses to electrostimulation relative to lidocaine-injected animals (Figure 8), with significantly reduced responses only at the 168 h time points of the Callicrate™and Beige-banded animals. This might reflect the significantly reduced levels of lidocaine in the injected animals at this time point (Figure 5B,C), even though the injected levels were above the therapeutic threshold for the Beige-banded cohort (Figure 5B). 4. Discussion 4. Discussion Moreover, the average heart rate and number of tail flicks were not significantly different between LLB-treated and lidocaine-injected animals (Supplemental Figures S1 and S2), suggesting a similar performance of these two methods of pain mitigation. From a safety perspective, no adverse events or mortalities were observed in either the treatment or control groups over the course of the in vivo field studies. Taken together, these results indicate that LLBs perform at least as well as lidocaine injections for short-term lidocaine delivery and pain mitigation (up to approximately 6 h). Moreover, LLBs generally outperform lidocaine injections for long-term delivery and pain mitigation (up to at least 7 days). Of note, we elected to compare the performance of the LLBs to injections of lidocaine into the spermatic cord rather than a ring block delivery because the LLB technology incorporates a skin permeation enhancer which is designed to deliver anesthetic deep into the scrotal tissue. Therefore, the cord injection was chosen over the ring block to facilitate a more accurate comparison to the LLB delivery profile. We acknowledge that future studies could also include a ring block control group to make an evaluation of deep versus surface anesthesia. The relatively short duration of lidocaine delivery and pain mitigation reported here for lidocaine injection at the time of castration is in keeping with other published studies. For instance, in a study of the effect of lidocaine on indicators of pain and distress during and after knife castration in beef calves, Melendez et al. (2018) noted that salivary cortisol concentrations were only significantly lower Animals 2020, 10, 2363 14 of 16 14 of 16 in lidocaine-injected versus untreated animals at 0.5 and 1 h after castration [5]. Stafford et al. (2002) found that lidocaine injection significantly reduced mean plasma cortisol concentrations in calves in response to band castration over a similar time period (0.5 to 3 h post-banding) [12]. Generally, this pilot work facilitated the prototype development and field validation of lidocaine-loaded castration bands for bovine pain mitigation. Due to the complex, multi-faceted nature of accurately assessing and reporting pain in animal studies [3,4], a robust, unambiguous measurement protocol should be employed. 4. Discussion 4. Discussion To evaluate the effectiveness of the LLB compared to lidocaine injection, the methods presented here combined the measurement of two behavioural responses (tail flicks and response to electrocutaneous stimulation) with the quantitation of one performance indicator (ADG), two physiological indicators (tissue inflammation and average heart rate), and tissue lidocaine levels. In future studies, it might be advantageous to include additional physiological indicators of pain and inflammation, such as substance P and salivary cortisol levels. While the field studies presented here lasted 7 days, future work should increase the study duration to approximately 3–6 weeks to reflect the actual duration of banded castration. A secondary objective of this work was to develop an objective assessment tool that generated more consistent results between different observers and different instruments [19] for the specific application of evaluating topical lidocaine delivery to generate an effective local anesthetic effect. To this aim, we took cues from the work of Melendez et al. (2018) [5], Musk et al. (2017) [19], and Winder et al. (2017) [22], and developed an evaluation protocol that incorporated a combination of physiological and behavioural metrics to evaluate pain response over the course of our field trials. Moreover, we adopted the use of an electrocutaneous nerve stimulation protocol (a standard of practice in guiding and monitoring peripheral nerve blocks) [23,24] to evaluate the loss of sensation in the animals’ scrotums over acute and chronic observation periods. For the purposes of this study, we define ‘acute’ and ‘chronic’ as the first several hours (up to approximately 6 h) and the first several days (up to at least one week) post-castration, respectively. Our method also incorporated the use of precision analytical HPLC to detect and quantify the lidocaine directly in the sampled tissue of interest. This analysis was originally incorporated into the trial design to better understand the LLB device performance; however, the addition of this analytical step provided this protocol with the means to attain comparable objective measurements between instruments (electrocutaneous stimulation results assessed against physiologically relevant levels of lidocaine in the tissue). The ultimate goal of this work is to provide producers with a practical and effective tool to provide long-term pain control for banded castration. 4. Discussion 4. Discussion The benefits to the industry include a simplified banding procedure (eliminating the need for lidocaine injection), reduced costs, societal and animal welfare benefits associated with improved pain control, and a potentially improved castration device (i.e., through increased ADG and enhanced recovery). Finally, as pain management is important for the well-being of the animal and castration recovery time [3,4], this work has obvious benefits for animal welfare. Author Contributions: Conceptualization, N.D.A., C.S., H.M.-B., B.R., K.S. and M.O.; methodology, N.D.A., C.S., H.M.-B., B.R., K.S., M.O., T.T., O.G., J.E.W. and R.T.; formal analysis, J.W.S., J.A.R., C.S., N.D.A., H.M.-B., B.R. and M.O.; investigation, J.W.S., N.D.A., C.S., H.M.-B., B.R., K.S. and M.O.; writing—original draft preparation, J.A.R. and J.W.S.; writing—review and editing, J.A.R., J.W.S., C.S., N.D.A. and J.E.W.; visualization, J.A.R. and Supplementary Materials: The following are available online at http://www.mdpi.com/2076-2615/10/12/2363/s1, Figure S1: Number of tail flicks for control (lidocaine injection) or treated (LLB) animals over time. Figure S2: Average heart rate for control (lidocaine injection) or treated (LLB) animals over time. References 1. Coetzee, J.F.; Nutsch, A.L.; Barbur, L.A.; Bradburn, R.M. A survey of castration methods and associated livestock management practices performed by bovine veterinarians in the United States. BMC Vet. Res. 2010, 6, 12. [CrossRef] [PubMed] 1. Coetzee, J.F.; Nutsch, A.L.; Barbur, L.A.; Bradburn, R.M. A survey of castration methods and associated livestock management practices performed by bovine veterinarians in the United States. BMC Vet. Res. 2010, 6, 12. [CrossRef] [PubMed] 2. AVMA. Literature Review on the Welfare Implications of Castration of Cattle. Am. Vet. Med. Assoc. 2014. Available online: https://www.avma.org/sites/default/files/resources/castration-cattle-bgnd.pdf (accessed on 8 December 2020). 2. AVMA. Literature Review on the Welfare Implications of Castration of Cattle. Am. Vet. Med. Assoc. 2014. Available online: https://www.avma.org/sites/default/files/resources/castration-cattle-bgnd.pdf (accessed on 8 December 2020). 3. Coetzee, J.F. A review of pain assessment techniques and pharmacological approaches to pain relief after bovine castration: Practical implications for cattle production within the United States. Appl. Anim. Behav. Sci. 2011, 135, 192–213. [CrossRef] 3. Coetzee, J.F. A review of pain assessment techniques and pharmacological approaches to pain relief after bovine castration: Practical implications for cattle production within the United States. Appl. Anim. Behav. Sci. 2011, 135, 192–213. [CrossRef] 4. Fajt, V.R.; Wagner, S.A.; Norby, B. Analgesic drug administration and attitudes about analgesia in cattle among bovine practitioners in the United States. J. Am. Vet. Med. Assoc. 2011, 238, 755–767. [CrossRef] [PubMed] 4. Fajt, V.R.; Wagner, S.A.; Norby, B. Analgesic drug administration and attitudes about analgesia in cattle among bovine practitioners in the United States. J. Am. Vet. Med. Assoc. 2011, 238, 755–767. [CrossRef] [PubMed] 5. Melendez, D.M.; Marti, S.; Pajor, E.A.; Sidhu, P.K.; Gellatly, D.; Moya, D.; Janzen, E.D.; Coetzee, J.F.; Schwartzkopf-Genswein, K.S. Effect of meloxicam and lidocaine administered alone or in combination on indicators of pain and distress during and after knife castration in weaned beef calves. PLoS ONE 2018, 13, e0207289. [CrossRef] [PubMed] 6. Olson, M.E.; Ralston, B.; Burwash, L.; Matheson-Bird, H.; Allan, N.D. Efficacy of oral meloxicam suspension for prevention of pain and inflammation following band and surgical castration in calves. BMC Vet. Res. 2016, 12, 102. [CrossRef] [PubMed] 7. NFACC. Code of Practice for the Care and Handling of Beef Cattle; National Farm Animal Care Council: Lacombe, AB, Canada, 2013; Available online: https://www.nfacc.ca/pdfs/codes/beef_code_of_practice.pdf (accessed on 8 December 2020). 8. Anderson, N. Castration of Calves; Ontario Ministry of Agriculture, Food and Rural Affairs: Guelph, ON, Canada, 2015. Available online: http://www.omafra.gov.on.ca/english/livestock/beef/facts/07-029.htm (accessed on 8 December 2020). 5. Conclusions Lidocaine-loaded elastration bands are capable of delivering significant quantities of lidocaine into scrotal tissues over at least seven days. This approach could provide long-term pain mitigation to the animals and, by avoiding surgery or the administration of injections, decrease time and handling costs for the producer. Supplementary Materials: The following are available online at http://www.mdpi.com/2076-2615/10/12/2363/s1, Figure S1: Number of tail flicks for control (lidocaine injection) or treated (LLB) animals over time. Figure S2: Average heart rate for control (lidocaine injection) or treated (LLB) animals over time. Author Contributions: Conceptualization, N.D.A., C.S., H.M.-B., B.R., K.S. and M.O.; methodology, N.D.A., C.S., H.M.-B., B.R., K.S., M.O., T.T., O.G., J.E.W. and R.T.; formal analysis, J.W.S., J.A.R., C.S., N.D.A., H.M.-B., B.R. and M.O.; investigation, J.W.S., N.D.A., C.S., H.M.-B., B.R., K.S. and M.O.; writing—original draft preparation, J.A.R. and J.W.S.; writing—review and editing, J.A.R., J.W.S., C.S., N.D.A. and J.E.W.; visualization, J.A.R. and 15 of 16 15 of 16 Animals 2020, 10, 2363 J.W.S.; supervision, N.D.A., J.E.W. and M.O.; project administration, C.S., H.M.-B. and N.D.A.; funding acquisition, J.E.W., N.D.A. and M.O. All authors have read and agreed to the published version of the manuscript. J.W.S.; supervision, N.D.A., J.E.W. and M.O.; project administration, C.S., H.M.-B. and N.D.A.; funding acquisition, J.E.W., N.D.A. and M.O. All authors have read and agreed to the published version of the manuscript. Funding: Partial salary support for J.W.S. came from an NSERC USRA, while laboratory studies were funded in part by NSERC Engage and Engage Plus grants to J.W. (award #531133-18 and 538474-19). CCR funded the field studies and additional support came from the Canada Research Chairs program and the University of Victoria. Development work and field trial work was supported in part by Canadian Advancing Agriculture Grant P074 (held by Alberta Beef Producers) and AAF Strategic Research and Develop Program Grant 2018R033R (held by CCR). Acknowledgments: The authors wish to acknowledge the study design inputs from Karen Schwartzkopf-Genswein and Daniela Meledez Suarez. The authors also wish to acknowledge the excellent technical assistance of Denis Nagel, Les Burwash, Andrea Hanson, Karen Wickerson and Patty Manum (animal handling and data collection), Henry Van Huigenbos, Wei (Ruth) Wei, Peri Donaghy, Tong Li, and Rebecca Hof. Finally, the authors wish to acknowledge the critical input from the Canadian cattle industry for design inputs and feedback, particularly Alberta Beef Producers, Alberta Farm Animal Care, and Mary-Anne Schwengler of the Calgary Central Feeders Association. 5. Conclusions Conflicts of Interest: J.A.R., C.S., N.D.A., and H.M.-B. receive a salary from Chinook Contract Research Inc. (CCR); M.O. and N.D.A. own shares of CCR, which has applied for patents relating to the contents of this manuscript. R.T. has patent interests. R.T. has patent interests. References 9. Carter, B.; Mathis, C.P.; Löest, C.; Wenzel, J. Castrating Beef Calves: Age and Method; New Mexico State University: College of Agricultural, Consumer, and Environmental Sciences: Las Cruces, NM, USA, 2011; Available online: https://aces.nmsu.edu/pubs/_b/B227.pdf (accessed on 8 December 2020). 10. Molony, V.; Kent, J.E.; Robertson, I.S. Assessment of acute and chronic pain after different methods of castration of calves. Appl. Anim. Behav. Sci. 1995, 46, 33–48. [CrossRef] 11. Golzari, S.E.; Soleimanpour, H.; Mahmoodpoor, A.; Safari, S.; Ala, A. Lidocaine and pain management in the emergency department: A review article. Anesth. Pain Med. 2014, 4, e15444. [CrossRef] [PubMed] 16 of 16 Animals 2020, 10, 2363 16 of 16 12. Stafford, K.J.; Mellor, D.J.; Todd, S.E.; Bruce, R.A.; Ward, R.N. Effects of local anaesthesia or local anaesthesia plus a non-steroidal anti-inflammatory drug on the acute cortisol response of calves to five different methods of castration. Res. Vet. Sci. 2002, 73, 61–70. [CrossRef] 13. Tennessen, T.; Connor, L.; Passillé, A.M.D.; Duncan, I.; Feddes, J.; Keaney, M.; Kochhar, H.; MacDonald, S.; Rushen, J.; Silversides, F.; et al. CCAC Guidelines on: The Care and Use of Farm Animals in Research, Teaching and Testing; Canadian Council on Animal Care: Ottawa, ON, Canada, 2009; Available online: https://www.ccac.ca/Documents/Standards/Guidelines/Farm_Animals.pdf (accessed on 8 December 2020). Rushen, J.; Silversides, F.; et al. CCAC Guidelines on: The Care and Use of Farm Animals in Research, Teaching and Testing; Canadian Council on Animal Care: Ottawa, ON, Canada, 2009; Available online: https://www.ccac.ca/Documents/Standards/Guidelines/Farm Animals.pdf (accessed on 8 December 2020). 14. Fierheller, E.E.; Caulkett, N.A.; Haley, D.B.; Florence, D.; Doepel, L. Onset, duration and efficacy of four methods of local anesthesia of the horn bud in calves. Vet. Anaesth. Analg. 2012, 39, 431–435. [CrossRef] [PubMed] 15. Alsaaod, M.; Schaefer, A.L.; Büscher, W.; Steiner, A. The Role of Infrared Thermography as a Non-Invasive Tool for the Detection of Lameness in Cattle. Sensors 2015, 15, 14513–14525. [CrossRef] [PubMed] 16. Purohit, R.C.; Hudson, R.S.; Riddell, M.G.; Carson, R.L.; Wolfe, D.F.; Walker, D.F. Thermography of the bovine scrotum. Am. J. Vet. Res. 1985, 46, 2388–2392. [PubMed] 7. Padula, C.; Colombo, G.; Nicoli, S.; Catellani, P.L.; Massimo, G.; Santi, P. Bioadhesive film for the transder delivery of lidocaine: In vitro and in vivo behavior. J. Control. Release 2003, 88, 277–285. [CrossRef] 17. Padula, C.; Colombo, G.; Nicoli, S.; Catellani, P.L.; Massimo, G.; Santi, P. Bioadhesive film for the transdermal delivery of lidocaine: In vitro and in vivo behavior. J. Control. © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). References Release 2003, 88, 277–285. [CrossRef] 18. Tanaka, E.; Yoshida, K.; Kawaai, H.; Yamazaki, S. Lidocaine Concentration in Oral Tissue by the Addition of 8. Tanaka, E.; Yoshida, K.; Kawaai, H.; Yamazaki, S. Lidocaine Concentration in Oral Tissue by the Additio Epinephrine. Anesth. Prog. 2016, 63, 17–24. [CrossRef] [PubMed] 19. Musk, G.C.; Jacobsen, S.; Hyndman, T.H.; Lehmann, H.S.; Tuke, S.J.; Collins, T.; Gleerup, K.B.; Johnson, C.B.; Laurence, M. Objective Measures for the Assessment of Post-Operative Pain in Bos indicus Bull Calves Following Castration. Animals 2017, 7, 76. [CrossRef] [PubMed] 20. Canozzi, M.E.A.; Mederos, A.; Manteca, X.; Turner, S.; McManus, C.; Zago, D.; Barcellos, J.O.J. A meta-analysis of cortisol concentration, vocalization, and average daily gain associated with castration in beef cattle. Res. Vet. Sci. 2017, 114, 430–443. [CrossRef] [PubMed] 21. Van der Saag, D.; Lomax, S.; Windsor, P.A.; Taylor, C.; Thomson, P.; Hall, E.; White, P.J. Effects of topical anaesthetic and buccal meloxicam on average daily gain, behaviour and inflammation of unweaned beef calves following surgical castration. Animal 2018, 12, 2373–2381. [CrossRef] [PubMed] 22. Winder, C.B.; LeBlanc, S.J.; Haley, D.B.; Lissemore, K.D.; Godkin, M.A.; Duffield, T.F. Clinical trial of local anesthetic protocols for acute pain associated with caustic paste disbudding in dairy calves. J. Dairy Sci. 2017, 100, 6429–6441. [CrossRef] [PubMed] 23. Bomberg, H.; Wetjen, L.; Wagenpfeil, S.; Schöpe, J.; Kessler, P.; Wulf, H.; Wiesmann, T.; Standl, T.; Gottschalk, A.; Döffert, J.; et al. Risks and Benefits of Ultrasound, Nerve Stimulation, and Their Combination for Guiding Peripheral Nerve Blocks: A Retrospective Registry Analysis. Anesth. Analg. 2018, 127, 1035–1043. [CrossRef] [PubMed] 24. Warren, V.T.; Fisher, A.G.; Rivera, E.M.; Saha, P.T.; Turner, B.; Reside, G.; Phillips, C.; White, R.P., Jr. Buffered 1% Lidocaine with Epinephrine Is as Effective as Non-Buffered 2% Lidocaine With Epinephrine for Mandibular Nerve Block. J. Oral Maxillofac. Surg. 2017, 75, 1363–1366. [CrossRef] [PubMed] Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
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Geological education scenario in India and role of open educational resources in the light of COVID-19 pandemic
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El escenario de la educación geológica en India y el rol de los recursos pedagógicos abiertos a las luces de la pandemia del covid-19 El escenario de la educación geológica en India y el rol de los recursos pedagógicos abiertos a las luces de la pandemia del covid-19 resources in the light of COVID-19 pandemic Omkar Vermaa*, Manthena Prashantha, Roberto Grecob, Ashu Khoslac, Kulwant Singhd a. Geology Discipline Group, School of Sciences, Indira Gandhi National Open University, New Delhi, India. E-mail: omkarverma@ignou.ac.in b Instituto de Geociências, Universidade Estadual de Campinas, Rua Carlos Gomes, 250, Campinas, SP, Brazil. c. Department of Geology, Panjab University, Chandigarh, India. d. Department of Geology, GGM Science College, Jammu Tawi, India. d. Department of Geology, GGM Science College, Jammu Tawi, India. Palabras clave: Educación geológica; datos de inscripciones; educación superior; recursos educativos abiertos; covid-19; trabajo de campo geológico; India. ABSTRACT Keywords: Geological education; Enrolment data; Higher education; OER; COVID-19; Geological fieldwork; India. Geological education plays a major role in the social, economic, and cultural growth and development of any coun- try. India is a vast diversified country with wide-ranging geological features, consisting of rocks of all geological ages with well-developed physiographic divisions. The Indian lithospheric plate is a storehouse of vast georesources and also serves as a natural field laboratory for developing and testing numerous geological principles. The exploration of Indian georesources began in the past; with the organized exploration began way back in the 1830s. The number of institutions offering geological education is, however, comparatively low. Thus, Geology as a science discipline is less popular in comparison with other science subjects such as Physics, Chemistry, Zoology, Botany, and Environmental science, based on enrolment data of the learners enrolled in academic sessions from 2011-2012 to 2018-2019 of the Master’s degree programs. Analysis indicates that teaching-learning resources of foreign origin are dominantly being adopted as learning resources in the teaching-learning pedagogy of degree programs in Geology, and are over-riding those of Indian origin. The COVID-19 pandemic is affecting geological education in two ways namely, the disruption of conventional (face-to-face) teaching together with not allowing learners of Geology programs to complete their compulsory out-door geological fieldwork assignments. The analysis of data gathered by an online questionnaire survey shows that the use of indigenous open educational resources in Geology appears as a plausible solution to overcome the learning barriers created by the COVID-19 pandemic, and also to enrich teaching-learning resources of Indian origin. This article provides an up-to-date detailed account of the necessity and evolution of geological education, the current popularity of Geology as a science discipline, the nature of available geological teaching-learning resources, the impact of the COVID-19 on geological education, and the role of open educational resources in providing quality and equita- ble geological education, whilst removing educational barriers created by COVID-19 in India. How to cite item: Verma, O., Prashanth, M., Greco, R., Khosla, A., & Singh, K. (2022). Geological education scenario in India and role of open educational resources in the light of COVID-19 pandemic. Earth Sciences Research Journal, 26(3), 239-254. https://doi. org/10.15446/esrj.v26n3.96209 Geological education scenario in India and role of open educational resources in the light of COVID-19 pandemic Geological education scenario in India and role of open educational EARTH SCIENCES RESEARCH JOURNAL Earth Sci. Res. J. Vol. 26, No. 2 (September, 2022): 239 - 254 EARTH SCIENCES RESEARCH JOURNAL Earth Sci. Res. J. Vol. 26, No. 2 (September, 2022): 239 - 254 GEOLOGY EARTH SCIENCES RESEARCH JOURNAL Earth Sci. Res. J. Vol. 26, No. 2 (September, 2022): 239 - 254 ISSN 1794-6190 e-ISSN 2339-3459 https://doi.org/10.15446/esrj.v26n3.96209 RESUMEN La educación geológica juega un papel importante en el desarrollo y en el crecimiento social, económico y cultural de cualquier país. La India es un país vasto y diverso y con un amplio rango de características geológicas que consiste en rocas de todas las edades geológicas y divisiones fisiográficas bien desarrolladas. La placa litosférica india es un depósito de grandes georecursos y también sirve como un laboratorio de campo para el desarrollo y evaluación de numerosos principios geológicos. La exploración organizada de los georrecursos indios comenzó en la década de 1830. El número de instituciones que ofrecen educación geológica es, sin embargo, comparativamente bajo. De este modo, la geología es una ciencia disciplinar menos popular en comparación con otras materias de estudio como la física, la química, la zoología, la botánica y la ciencia ambiental, con base en la información de inscripciones de los estudiantes en los programas de maestría para los períodos de 2011-2012 hasta 2018-2019. El análisis indica que los recursos foráneos de enseñanza-aprendizaje son adoptados dominantemente como los recursos de aprendizaje en la pedagogía de los progra- mas de pregrado en Geología y superan aquellas de origen indio. La pandemia del covid-19 está afectando la educación geológica en dos vías especificamente: la disrupción de la enseñanza convencional (presencial) junto con no permitir a los estudiantes de los programas de geología completar sus tareas obligatorias de trabajo de campo. El análisis de la in- formación recopilada por una encuesta digital muestra que el uso de recursos educativos nativos abiertos en geología es una solución posible para superar las barreras de aprendizaje creadas por la pandemia, y también enriquecen los recur- sos de enseñanza-aprendizaje de origen indio. Este artículo provee un recuento detallado y actualizado de la necesidad y evolución de la educación geológica, la actual popularidad de la geología como una ciencia disciplinar, la naturaleza de los recursos disponibles de enseñanza-aprendizaje, el impacto de la pandemia del covid-19 en la educación geológica, y el rol de los recursos pedagógicos para proveer educación geológica equitativa y de calidad mientras se remueven las barreras educativas creadas por la pandemia en India. Record Manuscript received: 28/05/2021 Accepted for publication: 17/08/2022 Record Manuscript received: 28/05/2021 Accepted for publication: 17/08/2022 2. Methodology y Geology plays a significant role in the overall growth and development of society. In support of geological education, an International Geoscience Education Organization (IGEO) was formally established in 2000 (King, 2019). The main objectives of the IGEO are to promote geoscience education at the global level, enhance its quality and equity, and increase its awareness in all sectors of society at all levels (http://www.igeoscied.org/about- the-igeo/). In this context, eight international conferences on geoscience education have been organized worldwide so far by the IGEO since 1993 (http://www.igeoscied.org/activities/geoscied/). The IGEO is also promoting open online teaching geological resources encompassing Earth learning ideas, complete teaching units, and geoscience textbooks for the use of the global teaching-learning community in various international languages (King, 2008; http://www.igeoscied.org/teaching-resources/). Apart from this, the IGEO has been conducting International Earth Science Olympiad since 2007 for popularizing geoscience education among school kids (http://www.igeoscied.org/activities/ieso-2/). Two methodological approaches were adopted for this study. The first approach involved the collection and analysis of literature to evaluate the importance of imparting geological education, trace the development of geological education from 1851 to the present in India, evaluate the status of geological education in comparison with other sciences at the level of Master’s degree programs, and finally, know the nature of geological TLR in India. It was found that almost all research dealing with the historical development of geological education in India was undertaken by historians. To date, no researcher with a geological background had investigated evolutionary development and the future of geological education in India. The data dealing with the enrolment and successful completion of Master’s degree programs in Geology, Physics, Chemistry, Botany, Zoology, and Environmental science for academic sessions from 2011-2012 to 2018- 2019 was obtained from the annual reports of the Ministry of Human Resources and Development (now renamed as the Ministry of Education), GOI within the ‘all India survey on higher education’ available on its website (http://aishe. nic.in/aishe/reports); this allowed comparative analysis between Geology and other science disciplines. The data dealing with learners’ enrolment and their successful completion in the Bachelor’s degree programs are not available; therefore, Bachelor’s degree programs were not included in this study. 1. Introduction media platforms like youtube. It has been shown that course-based-specific OER (including virtual labs, virtual field experiences, and Google Earth-based laboratory/field manuals) for Bachelor’s and Master’s degree programs in Geology are the need of the hour (Verma, 2021a). The use of OER in teaching- learning practice offers an opportunity to narrow down the gap of the TLR of Indian origin. OER provide off-campus specific-course-based learning during any pandemic like COVID-19, and also can, to an extent, facilitate the learners to complete their geological field-based assignments using Google Earth-based virtual field manuals. Research focusing on the past, present, and future of geological education is a major concern and is being carried out in the Western Hemisphere particularly, in the US and UK (King, 2008, 2018; GSA Position Statement, 2016; Dolphin et al., 2019). As a consequence, a journal has been launched, the “Journal of Geoscience Education” for publishing geological education research. To date, substantial research on geological education has not taken place in India, and probably, this article may be first of its kind in India. The primary objectives of this paper are threefold: first, to evaluate why geological education is necessary for the country and review its historical development; second, to assess the current popularity of Geology as a science discipline, the nature of available geological TLR, and impact of COVID-19 on higher geological education; and third, to evaluate OER role in providing high quality and equitable geological education, and in removing some of the educational barriers created by COVID-19. The usage of the word “Geology” in the scientific literature can be traced to the beginning of the eighteenth century (Howarth, 2020). In the late nineteenth century, the scope of the discipline of Geology was massively broadened in the Western World (King, 2008). As a result, different terminologies for the discipline of Geology came into existence. The new terms “Earth sciences” emerged in 1852; “Geoscience” appeared in 1929 and later, “Geological sciences” in 1938, in the geological literature (Wilson, 1883; Adams, 1938; Field, 1941; Howarth, 2020). All these words are synonymous with each other and broadly, involved in the study of the whole Earth and other planetary systems (Manduca & Kastens, 2012). Geology has been described as a historical and descriptive science, where processes and conditions of Earth, atmosphere, and oceans are investigated to understand Earth for the well-being of the society (Frodeman, 1995; Manduca & Kastens, 2012). 2. Methodology Both, geological education and research are essential in India, because the Indian subcontinent is endowed with significant amounts of georesources, whilst research on its geological settings has proved to be valuable in unraveling various mechanisms of the Earth system and generation of the georesources of the subcontinent (Wadia, 1964; Tandon et al., 1991; Naqvi, 2005; Radhakrishna, 2005; Santosh, 2012; Valdiya, 2016; Searle  &  Treloar, 2019; Kumari et al., 2020). Geological research in India began in 1836 (Oldham, 1856), but, Geology as an independent educational science discipline first appeared in a few Indian universities in the 1890s (Murty, 1982). An analysis of the enrolment data for the Master’s degree program in Geology shows that Geology is still a less popular science discipline in India. It also indicates that a majority of Teaching-Learning Resources (TLR) consisting of reading material used in higher geological education, are more of foreign origin, and may or may not be accessible to the teaching-learning community in India. Two types of negative impacts are visualized in the light of the current pandemic (i.e. COVID-19) on geological education, firstly, temporary suspension of classroom/face-to- face teaching, and secondly, the creation of an unfavorable environment for completing geological field-based compulsory assignments for Bachelor’s and Master’s degree programs. We downloaded two curricula of Bachelor’s degree programs in Geology from the website of the University Grant Commission and the curricula of Master’s degree programs from 25 universities (including Central Universities and State/Union Territory Universities) from their websites to discover the nature of existing TLR. The number of TLR of foreign and Indian origin recommended in the above-mentioned curricula were counted and analyzed. We had not disclosed the names of 25 universities and presented them as anonymous because the purpose of the research was to evaluate the nature of TLR available or used in India. The second method followed was a structured online survey. A Google-based questionnaire dealing with the current use of the OER for geological teaching-learning practices in India, their role in overcoming the learning restrictions imposed by the prevailing COVID-19 pandemic, and enriching teaching-learning resources of Indian origin were prepared and sent by email to numerous academicians and researchers covering almost all parts of the country. The responses received were evaluated and interpreted. 1. Introduction It is a scientific discipline of societal relevance in meeting many of its needs notably, natural resources, environmental quality, and resilience to natural hazards (King, 2019). Geoscientists use current natural phenomenon data to understand Earth’s past data to evaluate Earth’s present conditions and together, predict how Earth will likely behave in the future. Thus, geological education is the backbone of the socio-economic development of any country, and the dissemination of its knowledge to the different individuals (learners, public, and policymakers), is crucial in the decision-making processes, and for the long-term survival of humanity on the Mother Earth.i How to cite item: ISSN 1794-6190 e-ISSN 2339-3459 https://doi.org/10.15446/esrj.v26n3.96209 240 Omkar Verma, Manthena Prashanth, Roberto Greco, Ashu Khosla, Kulwant Singh 2. Methodology Recently, Open Education Resources (OER) are becoming popular among science disciplines and the global teaching-learning community has been using them extensively in day-to-day teaching-learning practices (Smith, 2009; Henderson & Ostashewski, 2018; y Verma, 2021a). OER are also gaining importance in India and currently, there are a few OER in Geology, which are available on online platforms of the Government of India (GOI), for example, the e-pgpathshala portal of the University Grant Commission (UGC) and Swayam of the Ministry of Human Resources Development (MHRD) (https:// epgp.inflibnet.ac.in/; https://swayam.gov.in/), and a few available on social Omkar Verma, Manthena Prashanth, Roberto Greco, Ashu Khosla, Kulwant Singh Geological education: why it is important in India? DC stands for Dharwar craton, BC Bastar craton, SC Singhbhum craton, BKC Bundelkhand craton, AC Aravalli craton, MC Meghalaya craton; PMB Pandyan mobile belt, EGMB Eastern Ghat mobile belt, SMB Satpura mobile belt, ADMB Aravalli-Delhi mobile belt; CKB Cuddapah- Kurnool basin, CGB Chhattisgarh basin, KB Kaladgi basin, BB Bhima basin, PB Pakhal basin, VB Vindhyan basin, GB Gwalior basin, MB Marwar basin; PGV Pranhita-Godavari valley, MV Mahanadi valley, DV Damodar valley, SV Satpura valley; DT Deccan traps, and RT Rajmahal traps. Figure 1. Map of India showing the main physiographic divisions and geological units (modified after Kumar, 2010; Valdiya, 2016; Shah, 2018). DC stands for Dharwar craton, BC Bastar craton, SC Singhbhum craton, BKC Bundelkhand craton, AC Aravalli craton, MC Meghalaya craton; PMB Pandyan mobile belt, EGMB Eastern Ghat mobile belt, SMB Satpura mobile belt, ADMB Aravalli-Delhi mobile belt; CKB Cuddapah- Kurnool basin, CGB Chhattisgarh basin, KB Kaladgi basin, BB Bhima basin, PB Pakhal basin, VB Vindhyan basin, GB Gwalior basin, MB Marwar basin; PGV Pranhita-Godavari valley, MV Mahanadi valley, DV Damodar valley, SV Satpura valley; DT Deccan traps, and RT Rajmahal traps. Prominent rift valleys such as Pranhita-Godavari, Satpura, Mahanadi, and Damodar (Fig. 1) probably developed during Proterozoic times, where thick sedimentary covers developed within these valleys that are termed Gondwana basins containing huge deposits of coal and a wealth of animal and plant fossils over Upper Palaeozoic to Mesozoic time intervals (Naqvi, 2005; Valdiya, 2016; Fareeduddin et al., 2020). The fossils of Gondwana deposits have provided data enabling the reconstruction of land ecosystems of Upper Palaeozoic to Mesozoic of peninsular India, together with their interrelations with ecosystems of continents that were adjacent at the time (Valdiya, 2016). The prominent Cretaceous volcanic traps (Rajmahal and Deccan) offer opportunities to study the interior of the Earth, the role of mantle plumes in the rifting and drifting of the former Gondwanan continents, the movement rate of the Indian plate, and the environmental impacts of volcanic eruption on contemporary biota (Beane et al., 1986; Courtillot, 1990; Verma, 2015; Verma et al., 2016, Mukherjee et al., 2016; Verma & Khosla, 2019; Kania et al., 2022; Khosla et al., 2022). Geological education: why it is important in India? Indian geological education has many strategies for meeting the varied needs of society, addressing the economic growth of the country using natural resources, and refining basic and applied principles of Geology (Sharma, 1998; Radhakrishna, 2005; Sheth, 2007; Jain et al., 2016; Mandal, 2016; Mukherjee et al., 2016; Mazumder et al., 2019; Parsons et al., 2020). Since geological 241 Geological education scenario in India and role of open educational resources in the light of COVID-19 pandemic and industrial materials, gemstones, and decorative stones, and are excellent sites for investigating Precambrian tectonism. The Proterozoic sedimentary successions have yielded much biotic evidence, which is useful in studying the early evolution of Earth’s life and atmosphere (Naqvi, 2005; Kumar, 2010; Santosh, 2012; Mohanty, 2015; Valdiya, 2016; Shah, 2018; Mazumder et al., 2019; Fareeduddin et al., 2020). education includes the whole Earth system, geoscientists study where we get most of the things that we use in everyday life, such as minerals, soils, oil and natural gas, energy, air, water, and food (Radhakrishna, 2005; Press, 2008). Geo- professionals also play a critical role in numerous other societal services like the management of waste (sewage, water pollution, landfills, non-biodegradable, nuclear, and recycling), site selection for the construction of mega-projects (dams, tunnels, reservoirs, roads, rail tracks, and buildings) together with providing remedial measures for various environment-related problems. Geoscientists study natural hazards (earthquakes, tsunamis, volcanoes, landslides, subsidence, floods, heat waves, droughts, natural contaminations, cyclones, and severe storms) to determine the magnitude of their risks and to develop resilient societies where life and property losses are minimized and preparedness, mitigation and recovery are initiated (Shalley, 1971; Chakraborti et al., 2011; Mora, 2013; Mukherjee, 2019; Valdiya, 2016; Fareeduddin et al., 2020; Ali et al., 2021; Verma, 2021b; Prashanth & Verma, 2022). In today’s world, due to the rapid increase in population and unsustainable practices in the use of natural resources, there is tremendous stress on Earth’s resources, causing many problems such as climate change, global warming, fossil fuels scarcity, natural resources depletion, biodiversity loss, extreme weather events, water contamination, and air pollution. Thus, nowadays, geo-professionals have been working to resolve various Earth and environment-related issues whilst ensuring sustainability in the use of natural resources, and their protection for future generations (Häggquist & Söderholm, 2015; Valdiya, 2016). Geological education: why it is important in India? Additionally, geological education has important societal implications in improving human health standards and the environment by suggesting key remedial measures to reduce the impact of geogenic elements and anthropogenic interventions in the Earth’s natural environment. The geogenic contaminants of groundwater, especially fluoride and arsenic, pose a serious threat to human health in India (Ali et al., 2016; Ali et al., 2021). The endemic fluorosis caused due to high concentration of fluoride in groundwater was recognized in 1937 and arsenic contaminated health effects in the year 1976. However, groundwater was not properly investigated for these contaminants until the late 1990s, resulting in the poor health of millions of people in India (Chakraborti et al., 2011; Raju, 2017; Ali et al., 2019; Saha et al., 2021). Figure 1. Map of India showing the main physiographic divisions and geological units (modified after Kumar, 2010; Valdiya, 2016; Shah, 2018). DC stands for Dharwar craton, BC Bastar craton, SC Singhbhum craton, BKC Bundelkhand craton, AC Aravalli craton, MC Meghalaya craton; PMB Pandyan mobile belt, EGMB Eastern Ghat mobile belt, SMB Satpura mobile belt, ADMB Aravalli-Delhi mobile belt; CKB Cuddapah- Kurnool basin, CGB Chhattisgarh basin, KB Kaladgi basin, BB Bhima basin, PB Pakhal basin, VB Vindhyan basin, GB Gwalior basin, MB Marwar basin; PGV Pranhita-Godavari valley, MV Mahanadi valley, DV Damodar valley, SV Satpura valley; DT Deccan traps, and RT Rajmahal traps. The awareness of geological time, the evolution of life, and Earth’s past environments through the deep time is critically useful for society in view of the alternative perspectives of myths and religions that help us to understand how to live in harmony with the Earth (Ayala, 2008; Kölbl-Ebert, 2009). Overall, geological education, information, and guidance play key roles in the decision-making process in numerous societal services such as sustainable natural resources management, mega-structures construction, natural hazards mitigation and management, local and regional planning, and environmental impact assessments (Häggquist & Söderholm, 2015). Geological education is also critical in meeting some of the sustainable development goals of the United Nations (UN) such as zero hunger, good health and well-being, clean water and environment, infrastructure, sustainable cities, climate action, and sustainable marine resources (UN, 2015; Stewart & Gill, 2017). Figure 1. Map of India showing the main physiographic divisions and geological units (modified after Kumar, 2010; Valdiya, 2016; Shah, 2018). Geological education: why it is important in India? The GSI has recognized 26 geological sites as National Geological Monuments of India that are located in various geologically rich states such as Andhra Pradesh, Telangana, Chhattisgarh, Gujarat, Himachal Pradesh, Karnataka, Kerala, Odisha, Rajasthan, Maharashtra, and Tamil Nadu (INTACH, 2016). However, there are numerous geoheritage sites are in India, which are yet to be recognized (Fig. 2). The Himalayan mountains belt, which is a product of the India-Asia collision that took place in Eocene times, created a unique monsoon system, and provided numerous natural resources, together with increased risks of natural hazards across the Indian subcontinent (Sharma, 1998; Valdiya, 2016; Searle & Treloar, 2019; Parsons et al., 2020). The monsoon system is a boon for the agro-economic sector of the subcontinent. There are opportunities to study the monsoon system to understand its mechanisms and the influence of the El Niño-Southern Oscillation cycle on it (Das, 2015; Dimri et al., 2016). The complex geological framework of the Himalayan makes it as an astonishing natural laboratory to investigate pre-, post-, and syn-collisional and depositional events associated with geodynamics of the Indian lithospheric plates and their influence on the environment. The rich fossiliferous Palaeozoic-Mesozoic successions of the north-western Himalaya provide excellent rock outcrops for investigating the biological evolution of invertebrates (corals, mollusks, brachiopods, echinoderms). The Himalayan Cenozoic successions contain well-preserved vertebrate fossils (particularly of mammals), which are useful for reconstructing mammalian diversity and their bearing on paleoecology, paleoenvironment, and paleobiogeography of the Indian subcontinent (Naqvi, 2005; Valdiya, 2016). The Himalayan contains large regions of glaciers, snow, and ice that serve as a significant freshwater reserve in Asia and provide uninterrupted water supply to the nine river systems of Asia, and these give a lifeline for nearly one-third of humanity. Climate change is seriously impacting the snow and ice cover of the Himalayan ecosystem, which needs to be investigated (Bisht et al. 2019; Sabin et al., 2020). The Himalaya is divided into five tectonic belts from north to south: Trans, Tethys, Greater, Lesser, and Outer Himalaya (Fig. 1). Each belt is bounded by prominent tectonic features such as Tethyan, Main Central, Main Boundary, and Himalayan Frontal Thrusts (Naqvi, 2005; Valdiya, 2016). These thrusts are seismically active zones and any tectonic movement along these thrusts can cause serious natural hazards such as slope instability, landslides, and earthquakes (Rajendran et al., 2017; Prashanth et al., 2021). Geological education: why it is important in India? A vast majority, around 75%, of total global landslides occur in the Asian continent alone, with a significant number of landslide events occurring along the Himalaya mountain belts (Froude & Petley, 2018). Thus, the Himalayan region provides unique opportunities for studying plate movements, plate boundaries, seismicity, neotectonics, slope stabilization, soil erosion proneness, climate change, glacial melting, harnessing geological resources, and mountain building processes (Jain & Sinha, 2005; Rajendran et al., 2017; Prashanth et al., 2021, 2022; Kouser et al., 2022; Tandon, 2022). 2a 2a 2b Figure 2. Photographs showing potential geoheritage sites in India. a. Huge granite batholith, situated nearly 50 km from Hyderabad along the Hyderabad-Warangal national highway at Bhongir town, Telangana, South India. This batholith is a part of the Eastern Dharwar Craton and around 2.7 to 2.5 billion years old. b. Quaternary fluvio-lacustrine deposits at Lamayuru, Union Territory of Ladakh, Northern India. These deposits are 105 m thick, dominantly composed of clay and sand layers, which develop a lunar landscape at Lamayuru. These deposits are popularly known as “moonland” of the Lamayuru. Both these geosites are places of tourist’s attraction (Courtesy: Naveen Kumar, Geologist, Geological Survey of India for b). 2b 2b The vast Indo-Gangetic plains of northern India comprise recent sediments, which were brought down from the rising Himalayan by its various rivers (Tandon et al., 1991; Tandon, 2022). These plains contain enormous water resources and their sediments have made the soil cover of the plains very fertile and so suitable for agriculture and industrial activities. As a result, nearly 50% of the total food grain production to feed 40% population of India comes from these plains (Pal et al., 2009). These plains are currently facing alarming amounts of soil degradation and water contamination (Mythili & Goedecke, 2016). The Great Thar Desert of Western India is an active area for exploring mineral resources and for harnessing renewable energy such as solar and wind. Thus, geoscientific research plays an influential role in studying the availability and spatial distribution of natural resources, regions of natural hazards, environment-related issues, and sustainable natural resources management, which are of direct concern to the society. Historically, the importance of the geological richness of the country was understood in earlier times by the Mughal Empire, and as a result, they ruled the subcontinent for 332 years from 1526 to 1858 (Babu & Nautiyal, 2013). Meanwhile, Britishers (i.e. Geological education: why it is important in India? The coastal regions of India contain a considerable cover of sedimentary successions such as Bombay high (Maharashtra), Cambay basin (Gujarat), Assam shelf (Assam), and Krishna-Cauvery basins (south India) largely formed in response to marine transgression and regression during Cenozoic time, and have provided valuable sources of lignite, coal, oil and natural gas (Biswas, 1982, 1987; Nagendra et al., 2011; Shah, 2018). These allow us to study the phenomenon of the past sea level changes concerning changes in paleoclimate (Naqvi, 2005; Kundal & Humane, 2007; Valdiya, 2016; Fareeduddin et al., 2020 y Verma, 2021b). Apart from education, geological research on the Indian lithospheric plate provides a platform for generating new geological ideas and offers many opportunities to study the geodynamics of the Earth on the global scale (Tandon et al., 1991; Radhakrishna, 2005; Naqvi, 2005; Jain et al., 2016; Santosh, 2012; Mandal, 2016; Mukherjee et al., 2016; Valdiya, 2016; Searle & Treloar, 2019; Parsons et al., 2020). The Indian subcontinent has a distinctive topography with the Indian Ocean lying to the south and the snow-covered Himalayan mountains belt to the north. It includes three main physiographic divisions (Fig. 1): peninsular India to the south, extra-peninsular India (i.e., Himalayan division) to the north, and the Indo-Gangetic plains sandwiched between them (Shah, 2018). The Indian lithospheric plate preserves the vast history of the Earth from Archean to Holocene (4.6 billion years to the present) in its rock record (Naqvi, 2005; Santosh, 2012; Mohanty, 2015; Valdiya, 2016; Shah, 2018). The peninsular region of India is dominantly composed of rocks of the Precambrian age and is an amalgamation of Archean cratons (Dharwar, Bastar, Singhbhum, Bundelkhand, Aravalli, and Meghalaya), and Proterozoic mobile belts (Eastern Ghat, Pandyan, Satpura, and Aravalli-Delhi) and sedimentary basins (Vindhyan, Kurnool-Cuddapah, Chhattisgarh, Gwalior, Pakhal, Marwar, Bhima, and Kaladgi) (Fig. 1; Valdiya, 2016; Shah, 2018). The cratons and mobile belts suffered various phases of Archean tectonic activity and as a consequence, they are a rich storehouse of varied economic minerals, building 242 Omkar Verma, Manthena Prashanth, Roberto Greco, Ashu Khosla, Kulwant Singh “geosites of significant educational, cultural, scientific, and aesthetic value” (https://www.americasgeoheritage.com/geoheritage/). India has numerous rich and diversified geocultural heritage sites and thus, provides ample opportunities to promote education, research, and tourism related to geoheritage (Shekhar et al., 2019; Biswas & Chauhan, 2021; Chauhan et al., 2021). Development of Indian higher geological education Development of Indian higher geological education The study of geological phenomena in India had been recorded from time immemorial when Indians started to observe and record the behavior of Earth’s natural processes. The Bronze Age and Iron Age, which were associated with the growth and development of human civilizations and their presence in the country, clearly indicate the exploration and utilization of mineral resources by ancient Indians. There are several references for using basic concepts of Geology and Metallurgy in the ancient literature of the country. However, reliable evidence of the early existence of geological information and its utilization for the development of society comes from an old Treatise “Arthashastra”, composed by an ancient Indian statesman and philosopher, Kautilya, around 321-296 BC (Chakraborty, 1970; Murty, 1979). This Treatise provides an account of geological knowledge, which is used to discover and extract metals from various ores (GOI, 2012). The growth of Geology as an independent science discipline emerged in the eighteenth century (Chakraborty, 1971; Rajendran, 2019). The initial phase of realization of the importance of Geology in India was seen with the establishment of the Survey of India in 1767 and the Asiatic Society of Bengal in 1784 by the East India Company. The main objective of the Survey of India was to map the country and produce maps at different scales for discovering natural resources and Society had as its objective “enquiry into the history and antiquities, arts, science and literature of Asia” (Chakraborty, 1971). The results of the survey and society together later played a profound role in the growth of geological studies in India. The opening of a museum in Calcutta (now Kolkata) in 1840 by the East India Company was considered a step towards the beginning of geological education (Stubblefield, 1970). Indeed, the East India Company understood the importance of the geological richness of India, especially the coal resources before 1835. As a consequence, they established a Coal Committee in 1836 for discovering the coal and mineral resources of the country (Kumar, 1982). Figure 3. Map of India showing the distribution of higher learning institutes offering geological education in India.f Based on the rich and varied geology of the subcontinent, with its huge resource potential, the East India Company formally established the world’s second-largest organization, the Geological Survey of India (GSI) in 1851, to undertake geological mapping and exploration of mineral resources of the country (Oldham, 1856). Development of Indian higher geological education In 1858, the East India Company developed into the British Raj (i.e. Government of colonial India). But before the 1850s, the colleges of the East India Company taught Geology and Mineralogy, but there was no separate department of Geology (Larwood, 1958; Tolman, 2016). p p gy ( ) The opening of the GSI marked the informal beginning of geological higher education in India (Kumar, 1982; Murty, 1982; Palit, 2013). Shortly after its establishment, Henry B. Medlicott, an Irish geologist, came to India in 1854 to become a Professor of Geology at the Thomson College of Civil Engineering, Roorkee (now Indian Institute of Technology, Roorkee) founded in 1847. He was probably the first teacher of Geology in India. For a long period, British geologists undertook all activities of the GSI and they were of the view that Indians were not capable of doing any kind of sophisticated teaching and research in Geology, and no Indian university was properly equipped to impart higher geological education. In fact, they were not much interested to open geological education in the higher learning institutes of India (Kumar, 1982; Tolman, 2016). As a consequence, geological education did not become part of higher education in Indian universities until the 1870s (Kumar, 1982; Tolman, 2016). Over time, the British Raj found difficulties in recruiting geologists from Europe because they rejected the offer of British Raj to join GSI due to limited financial benefits and serious health problems in India; particularly, unfavorable climatic conditions, which often caused their death within a few years of joining the GSI (Grout, 1995; Kumar, 1995). This led to a shortage of geologists in the GSI and to fill this gap, the British Raj decided to recruit Indian geologists. In 1886, the British Raj constituted two positions exclusively for Indian geologists within the GSI and also felt the need to establish a sound education system to teach Geology (Kumar, 1995).i Figure 3. Map of India showing the distribution of higher learning institutes offering geological education in India. There were around 14 universities in the country that offered geological education before1952 (Stubblefield, 1970). Following one and a half decades of independence, out of a total of 35 universities, around 20 had departments of Geology (Wadia, 1964). Later, geological education witnessed a substantial expansion, thus, many Geology departments were opened in various colleges and universities across the country. Geological education: why it is important in India? Over time, many Geology departments were opened in other universities namely, Banaras Hindu University, Varanasi in 1923; Indian School of Mines (now Indian Institute of Technology), Dhanbad in 1926; Andhra University, Visakhapatnam in 1941; Lucknow University, Lucknow in 1942; Aligarh Muslim University, Aligarh in 1946; Patna University, Patna in 1946, and Rashtrasant Tukadoji Maharaj University, Nagpur in 1946 (Stubblefield, 1970; Bhattacharya, 2016). Thus, the development of geological education was seen as a by-product of the GSI growth and rich georesources of the country. (now Chennai), and Bombay University in the 1890s (Murty, 1982). Geology as an optional subject was introduced at Bombay University in 1879. In 1892, a separate department of Geology was opened at the Presidency College (now Presidency University), Kolkata. Another Presidency College (now Madras University) at Chennai already had Geology as an auxiliary subject, but an independent department of Geology was started in 1910 (Murty, 1982). Meanwhile, the spread of geological education also reached northern India with the visit of the Prince of Wales to Jammu in 1906. To commemorate his visit, His Highness, the Maharaja (i.e. ruler) Sir Pratap Singh of Jammu and Kashmir, built the Prince of Wales College (now Government Gandhi Memorial Science College and is a part of the Cluster University of Jammu) on the banks of the River Tawi. In this college, Geology education commenced in 1907, under the stewardship of the renowned Indian geologist, Dr. D. N. Wadia (Stubblefield, 1970). Over time, many Geology departments were opened in other universities namely, Banaras Hindu University, Varanasi in 1923; Indian School of Mines (now Indian Institute of Technology), Dhanbad in 1926; Andhra University, Visakhapatnam in 1941; Lucknow University, Lucknow in 1942; Aligarh Muslim University, Aligarh in 1946; Patna University, Patna in 1946, and Rashtrasant Tukadoji Maharaj University, Nagpur in 1946 (Stubblefield, 1970; Bhattacharya, 2016). Thus, the development of geological education was seen as a by-product of the GSI growth and rich georesources of the country. Given this wide geological background, geological education is crucial for India to refine existing geological principles, establish geoheritage sites, explore georesources and ensure their sustainability, and resolve geo- environment-related problems across the country. Geological education: why it is important in India? East India Company) invaded the country in 1757, and later, expanded their imperialism, and ruled the country from 1858 to 1947 (Wagh, 2018). They understood mineral resource richness, especially the coal resources of the country, and extensively mined several mineral resources during their rule (Fox, 1947). The country still has many georesources. Some world-famous diamonds namely, Kohinoor, Great Moghul, and Regent were discovered from gravels of the Krishna valley that were derived from the Krishna lamproite (ultramafic igneous rock) field, near the north-eastern margin of the Cuddapah Basin, southern India (GSI, 2011). Recently, geoheritage emerged as an important field of public and scientific interest that promotes geoscience education, research, geotourism, and sustainable development. Geoheritage is an essential part of the natural (geocultural) heritage and encompasses 2b 2b Figure 2. Photographs showing potential geoheritage sites in India. a. Huge granite batholith, situated nearly 50 km from Hyderabad along the Hyderabad-Warangal national highway at Bhongir town, Telangana, South India. This batholith is a part of the Eastern Dharwar Craton and around 2.7 to 2.5 billion years old. b. Quaternary fluvio-lacustrine deposits at Lamayuru, Union Territory of Ladakh, Northern India. These deposits are 105 m thick, dominantly composed of clay and sand layers, which develop a lunar landscape at Lamayuru. These deposits are popularly known as “moonland” of the Lamayuru. Both these geosites are places of tourist’s attraction 243 (now Chennai), and Bombay University in the 1890s (Murty, 1982). Geology as an optional subject was introduced at Bombay University in 1879. In 1892, a separate department of Geology was opened at the Presidency College (now Presidency University), Kolkata. Another Presidency College (now Madras University) at Chennai already had Geology as an auxiliary subject, but an independent department of Geology was started in 1910 (Murty, 1982). Meanwhile, the spread of geological education also reached northern India with the visit of the Prince of Wales to Jammu in 1906. To commemorate his visit, His Highness, the Maharaja (i.e. ruler) Sir Pratap Singh of Jammu and Kashmir, built the Prince of Wales College (now Government Gandhi Memorial Science College and is a part of the Cluster University of Jammu) on the banks of the River Tawi. In this college, Geology education commenced in 1907, under the stewardship of the renowned Indian geologist, Dr. D. N. Wadia (Stubblefield, 1970). Development of Indian higher geological education At present, there are more than 153 higher learning institutes that host Geology departments imparting geological education in India up to a Master’s degree level (excluding colleges). These institutes include various universities (state/union territory, central and private), Indian Institutes of Technology, Indian Institute of Science, Indian Statistical Institute, and Indian Institutes of Science Education and Research (Fig. 3). Apart from conventional learning systems, geological education is also offered through open and distance modes of learning in India, with the opening of departments at Dr. B. R. Ambedkar Open University in 1991, and Indira Gandhi National Open University in 2010. Currently, higher education in Geology is being offered at three-degree levels across the country viz., To fill the shortage gaps of geologists and associated skilled manpower needed in the GSI and through continuous struggle by the Indian educationists, a more systematic effort was made by the British Raj and GSI for opening the Geology departments at the Presidency Colleges of Kolkata and Madras 244 Omkar Verma, Manthena Prashanth, Roberto Greco, Ashu Khosla, Kulwant Singh Bachelor’s degree programs of three-year duration, Master’s degree programs of two-year duration, and integrated Bachelor’s-Master’s degree programs of five-year duration. Apart from this, Ph.D. in Geology is a common research degree program in Indian universities.i Bachelor’s degree programs of three-year duration, Master’s degree programs of two-year duration, and integrated Bachelor’s-Master’s degree programs of five-year duration. Apart from this, Ph.D. in Geology is a common research degree program in Indian universities.i the performance of Master’s degree programs in Geology, in terms of the successful completion of the program by learners and to make comparisons between the Master’s degree programs in Geology and other science disciplines to evaluate the percentage of their success rate and to ascertain awareness of Geology among the learners. For this analysis, five science disciplines comprising Physics, Chemistry, Botany, Zoology, and Environmental science were selected. The data about the learners’ enrolment and their successful pass rates (i.e. completion of programs) for the academic sessions from 2011-2012 to 2018-2019 of Master’s degree programs in Geology, Physics, Chemistry, Botany, Zoology, and Environmental science was obtained from reports of the MHRD, GOI on “all India survey on higher education” (Table 1). Status of Geology education among other sciences: a comparative analysis Numerous public and private sectors including non-governmental organizations in India offer job opportunities to those who had qualified with a Master’s degree in Geology. Thus, an analysis was carried out to evaluate Table 1. Learner’s enrolment and successful completion data of Master’s degree programs in Geology, Physics, Chemistry, Botany, Zoology, and Environmental science (complied after MHRD Reports, 2014, 2015a, b, 2016a, b, 2017, 2018, 2019). Academic sessions Master’s programs in Geology Physics Chemistry Botany Zoology Environmental science Enrol- ment Quali- fied Enrol- ment Quali- fied Enrol- ment Quali- fied Enrol- ment Quali- fied Enrol- ment Quali- fied Enrol- ment Qualified 2011-2012 3564 1801 36954 16585 73984 34588 22850 10288 27581 12606 4520 3335 2012-2013 4028 1962 42898 17202 77858 35495 24896 11140 31965 14008 5100 2549 2013-2014 4749 1786 52496 18829 90101 35142 29680 12276 36559 15184 5395 3129 2014-2015 5179 2008 56824 20558 95295 37142 32619 12140 38850 15703 5797 2528 2015-2016 5597 2076 60889 20759 99888 34639 36736 12473 41025 13899 5393 2462 2016-2017 6039 2133 69754 24211 114328 38216 42542 14625 48774 17453 6252 2484 2017-2018 6281 2469 75114 26915 125805 44027 43967 17131 51672 19134 6766 2553 2018-2019 7134 2843 72797 28737 124526 46925 43036 19208 50904 20903 7281 3243 Total 42571 17078 467726 173796 801785 306174 276326 109281 327330 128890 46504 22283 Average completion percentage 40.11 37.15 38.18 39.54 39.37 47.91 Figure 4. a. Pie-chart showing relative enrolment data percentage for Master’s degree programs in six science disciplines of academic sessions from 2011-2012 to 2018- 2019. b. Bar-chart showing average successful completion percentage of learners in Master’s programs in six science disciplines of academic sessions from 2011-2012 to 2018-2019. Refer to Table 1 for enrolment data. Env sci stands for Environmental science. 40.86% 23.84% 16.68% 14.09% 2.37% 2.16% Chemistry Physics Zoology Botany Envi sci Geology 4b Env sci Geology Botany Zoology Chemistry Physics 47.91 40.11 39.54 39.37 38.18 31.15 Successful compleƟon percentage Table 1. Learner’s enrolment and successful completion data of Master’s degree programs in Geology, Physics, Chemistry, Botany, Zoology, and Environmental science (complied after MHRD Reports, 2014, 2015a, b, 2016a, b, 2017, 2018, 2019). Development of Indian higher geological education the performance of Master’s degree programs in Geology, in terms of the successful completion of the program by learners and to make comparisons between the Master’s degree programs in Geology and other science disciplines to evaluate the percentage of their success rate and to ascertain awareness of Geology among the learners. For this analysis, five science disciplines comprising Physics, Chemistry, Botany, Zoology, and Environmental science were selected. The data about the learners’ enrolment and their successful pass rates (i.e. completion of programs) for the academic sessions from 2011-2012 to 2018-2019 of Master’s degree programs in Geology, Physics, Chemistry, Botany, Zoology, and Environmental science was obtained from reports of the MHRD, GOI on “all India survey on higher education” (Table 1). The need for geology education at the school level in India was first highlighted by Wadia in 1964 (Stubblefield, 1970). So far, the picture of geology education offered at the school level is very sparse; it is largely neglected in comparison with other science disciplines: Physics, Chemistry, Mathematics, Biology, Engineering, and Computer science (Tandon, 2005). From kindergarten to 10th grade of high school level (pupils with age range 4 to 16 years), geology education is taught as a part of either general studies or social sciences (Paliwal, 2005). In 11th and 12th grade higher school education (pupils with age range 16 to 18 years), there are very few school boards of Indian states/union territories offering Geology as an independent subject in their science or arts streams. The states/union territories that do so are Kerala, Rajasthan, Jammu and Kashmir, Jharkhand, Karnataka, Maharashtra, and Manipur (Paliwal, 2005; Padmanabhan, 2018). Analysis of the data shows that there was an increasing trend in enrolment numbers of learners in the Master’s degree programs of all six science disciplines in the academic sessions 2011-2012 to 2018-2019 (Table 1). Nearly 40.86% of learners were enrolled in the Master’s degree program in Chemistry whilst a minimum of learners, at 2.16%, were enrolled in the Master’s degree program in Geology (Fig. 4a). Surprisingly that the importance of Geology in India was realized in 1851 with the establishment of the GSI, but the enrolment percentage of the Master’s degree program in Geology indicates that Geology had the lowest popularity as a science subject among these six science disciplines (Fig. 4a). Geology education among other sciences: a comparative ana Status of Geology education among other sciences: a comparative analysis Academic sessions Master’s programs in Geology Physics Chemistry Botany Zoology Environmental science Enrol- ment Quali- fied Enrol- ment Quali- fied Enrol- ment Quali- fied Enrol- ment Quali- fied Enrol- ment Quali- fied Enrol- ment Qualified 2011-2012 3564 1801 36954 16585 73984 34588 22850 10288 27581 12606 4520 3335 2012-2013 4028 1962 42898 17202 77858 35495 24896 11140 31965 14008 5100 2549 2013-2014 4749 1786 52496 18829 90101 35142 29680 12276 36559 15184 5395 3129 2014-2015 5179 2008 56824 20558 95295 37142 32619 12140 38850 15703 5797 2528 2015-2016 5597 2076 60889 20759 99888 34639 36736 12473 41025 13899 5393 2462 2016-2017 6039 2133 69754 24211 114328 38216 42542 14625 48774 17453 6252 2484 2017-2018 6281 2469 75114 26915 125805 44027 43967 17131 51672 19134 6766 2553 2018-2019 7134 2843 72797 28737 124526 46925 43036 19208 50904 20903 7281 3243 Total 42571 17078 467726 173796 801785 306174 276326 109281 327330 128890 46504 22283 Average completion percentage 40.11 37.15 38.18 39.54 39.37 47.91 Figure 4. a. Pie-chart showing relative enrolment data percentage for Master’s degree programs in six science disciplines of academic sessions from 2011-2012 to 2018- 2019. b. Bar-chart showing average successful completion percentage of learners in Master’s programs in six science disciplines of academic sessions from 2011-2012 to 2018-2019. Refer to Table 1 for enrolment data. Env sci stands for Environmental science. 40.86% 23.84% 16.68% 14.09% 2.37% 2.16% Chemistry Physics Zoology Botany Envi sci Geology 4b Env sci Geology Botany Zoology Chemistry Physics 47.91 40.11 39.54 39.37 38.18 31.15 Successful compleƟon percentage Figure 4. a. Pie-chart showing relative enrolment data percentage for Master’s degree programs in six science disciplines of academic sessions from 2011-2012 to 2018- 2019. b. Bar-chart showing average successful completion percentage of learners in Master’s programs in six science disciplines of academic sessions from 2011-2012 to 2018-2019. Refer to Table 1 for enrolment data. Env sci stands for Environmental science. 245 The analysis of recommended TLR by the UGC for Bachelor’s degree program in Geology under its CBCS and LOCF schemes shows that 75.69% of the TLR listed in the syllabi are of foreign origin, and only 24.31% are of Indian origin (Table 2; Fig. 5a). Status of Geology education among other sciences: a comparative analysis Similarly, the analysis of recommended TLR in the syllabi of Master’s degree programs in Geology of 25 universities of five Indian regions namely, northern, western, southern, eastern, and central shows that these regions contain 81.36%, 81.05%, 78.30%, 80.20%, 76.29%, and 18.64%, 18.95%, 21.70%, 19.80%, 23.71% TRL of foreign and Indian origin, respectively (Table 3; Fig. 5b). As a whole, the recommended TRL of these 25 universities include 79.68% of foreign origin, and only 20.32% of Indian origin (Table 3; Fig. 5b). A few of the MOOCs in Geology such as Physical and Structural Geology, Stratigraphy and Palaeontology, Crystallography and Mineralogy, Photogeology and Remote Sensing, Metamorphic Petrology and Thermodynamics, Metamorphic Petrology, and Environmental Geology are on offer through the UGC-MOOCs portal (http://ugcmoocs.inflibnet.ac.in/ ugcmoocs/moocs_courses.php). In addition, some modules related to geological courses namely, Igneous and Metamorphic Petrology, Sedimentology and Petroleum Geology, Crystallography and Mineralogy, Economic Geology and Mineral Resources of India, Hydrogeology and Engineering Geology, Remote Sensing and Geographic Information System are available as open TLR at e-pgpathshala portal of the UGC (https://epgp.inflibnet.ac.in/Home/ ViewSubject?catid=448). Further data analysis of learner’s enrolment and their successful completion in Master’s programs in all six science disciplines from 2011- 2012 to 2018-2019 had given quite interesting results (Fig. 4b). The results indicate that the Master’s degree program in Geology had a very good learner’s average completion rate i.e. 40.11%, and stands second, after average program completion rate of Environmental science, which is 47.91% (Fig. 4b). The average successful program completion rate for Botany, Zoology, and Chemistry was 39.59%, 39.37%, and 38.18%, respectively. Physics had the lowest average completion rate, which is 31.15% (Fig. 4b). This may indicate that better quality education was available to the qualified learners of the Master’s program in Geology, and alternatively, reflects a higher quality of qualified postgraduates of Geology. The Union Public Service Commission (UPSC) of the GOI recruits candidates who had Master’s degrees in Geology as geologists for the GSI almost every year. The applicants from all over the country appear for the UPSC written examination to obtain geologist positions in the GSI after completing their Master’s degree in Geology. Thus, the performance of applicants in the UPSC geologists’ written examination can provide a means of checking the quality of masters-level geological education in India. Nature of Teaching-Learning Resources in Geology Over the past few years, several reforms in the country’s higher educational system had been made by the UGC and Department of Higher Education of the MHRD of the GOI. Recently, the UGC implemented a minimum course curriculum under, the Choice-Based Credit System (CBCS) and Learning Outcomes-Based Curriculum Framework (LOCF) for Bachelor’s degree programs in India to provide high-quality and equitable education (UGC, 2015a, 2019). Under the CBCS and LOCF, the UGC issued a national curriculum in Geology for implementation in Bachelor’s (both general and honors) degree programs for all higher education institutes in India (UGC, 2015b, c, 2019). The MHRD had taken several remarkable steps in enhancing the quality and providing equity with extensive use of Information and Communication Technology (ICT) in higher education. Nowadays, online higher education is also being offered to learners through Massive Open Online Courses (MOOCs) through various online platforms (http://www.sakshat.ac.in). In addition, TLR in the form of the OER in various disciplines for the use of teachers and learners have also been provided by the GOI (e.g., https://epgp.inflibnet.ac.in/). CBCS LOCF CBCS-LOCF 79.08 72.23 75.69 20.92 27.77 24.31 5a 5a To know the nature of the TLR in Geology for its Bachelor’s and Master’s degree programs, the TLR recommended for all the courses of these programs were evaluated. For Bachelor’s degree programs, the TLR mentioned in UGC- CBCS and LOCF in Geology, in the form of recommended books/texts, were evaluated (Table 2). For Master’s degree programs, the Master’s curricula of 25 universities (including five universities each from northern, western, southern, eastern, and central regions of India) were downloaded from their respective websites, and the TLR were recommended for all courses of programs were evaluated (Table 3). Northen Western Southern Eastern Central Total TRL 81.36 81.05 78.3 80.2 76.29 79.68 18.64 18.95 21.7 19.8 23.71 20.32 TRL percentage of foreign origin TRL percentage of Indian origin 5b Table 2. Statistics of the TLR recommended for Bachelor’s program in Geology by the UGC. Curricula types of the UGC Total TLR recom- mended TLR of foreign origin TLR of Indian origin No. % No. % CBCS curriculum 239 189 79.08 50 20.92 LOCF curriculum 234 169 72.23 65 27.77 Total TLRs recommended 473 358 75.69 115 24.31 Table 2. Statistics of the TLR recommended for Bachelor’s program in Geology by the UGC. 5b Figure 5. a. Status of Geology education among other sciences: a comparative analysis In the past few years of the UPSC recruitment process for geologists had shown that the subject-specific knowledge of the applicants was a little low and applicants were securing average marks in the written examination, i.e. 30 to 40% (Saha, 2016, 2018). j ) CBCS LOCF CBCS-LOCF 79.08 72.23 75.69 20.92 27.77 24.31 TRL percentage of foreign origin TRL percentage of Indian origin 5a Northen Western Southern Eastern Central Total TRL 81.36 81.05 78.3 80.2 76.29 79.68 18.64 18.95 21.7 19.8 23.71 20.32 TRL percentage of foreign origin TRL percentage of Indian origin 5b Figure 5. a. Bar-chart showing percentage of the TLR recommended in the curricula issued by the UGC under its CBCS and LOCF schemes for Bachelor’s degree programs in Geology. b. Bar-chart showing the percentage of TLR recommended in the curricula of 25 universities across India for their Master’s degree programs in Geology. Refer to Table 2 for the TLR data. TRL percentage of foreign origin TRL percentage of Indian origin Nature of Teaching-Learning Resources in Geology Bar-chart showing percentage of the TLR recommended in the curricula issued by the UGC under its CBCS and LOCF schemes for Bachelor’s degree programs in Geology. b. Bar-chart showing the percentage of TLR recommended in the curricula of 25 universities across India for their Master’s degree programs in Geology. Refer to Table 2 for the TLR data. 246 Omkar Verma, Manthena Prashanth, Roberto Greco, Ashu Khosla, Kulwant Singh Table 3. Statistics of the TLR recommended for Master’s program in Geology covering all parts of India. The letters A to Y have been sequentially assigned to these universities within parentheses for identification purposes as their names have been kept anonymous. S. No. University selected for accessing curricula / syllabi Total TRL rec- ommended TLR of foreign origin TLR of Indian or- igin Region of India No. % No. % 1. Union Territory University (A) 274 218 79.56 56 20.44 Northern 2. Union Territory University (B) 151 128 84.76 23 15.24 3. State University (C) 185 139 75.14 46 24.86 4. State University (D) 240 197 82.10 43 17.90 5. Central University (E) 202 174 86.14 28 13.86 Subtotal of TRL 1052 856 81.36 196 18.64 6. State University (F) 222 191 86.10 31 13.90 Western 7. State University (G) 275 221 80.36 54 19.64 8. State University (H) 123 97 78.86 26 21.14 9. State University (I) 200 164 82.00 36 18.00 10. State University (J) 394 311 78.94 83 21.06 Subtotal of TRL 1214 984 81.05 230 18.95 11. Central University (K) 150 122 81.34 28 18.66 Southern 12. State University (L) 187 150 80.21 37 19.79 13. State University (M) 287 210 73.17 77 26.83 14. State University (N) 156 131 83.97 25 16.03 15. State University (O) 192 148 77.08 44 22.92 Subtotal of TRL 972 761 78.30 211 21.70 16. State University (P) 148 114 77.03 34 22.97 Eastern 17. Central University (Q) 182 149 81.87 33 18.13 18. Central University (R) 267 210 78.65 57 21.35 19. Central University (S) 249 206 82.73 43 17.27 20. State University (T) 169 135 79.88 34 20.12 Subtotal of TRL 1015 814 80.20 201 19.80 21. State University (U) 121 96 79.34 25 20.66 Central 22. Central University (V) 172 139 80.82 33 19.18 23. State University (W) 145 114 78.62 31 21.38 24. Central University (X) 167 109 65.27 58 34.73 25. OER and their role in geological higher education OER and their role in geological higher education The global teaching-learning community has come to understand the real value of the OER at a time when COVID-19 has led to the sudden closure of educational institutions (Huang et al., 2020). In order to meet educational challenges posed by the COVID-19 outbreak, many countries, including India, advised institutions to adopt a policy of undisrupted learning by offering online, remote, and distance teaching (Huang et al., 2020; UGC, 2020). In this context, OER emerged as ideal educational resources because they are in digital format, freely accessible at anytime, anywhere, and easy to incorporate into the existing learning system of any educational institution (Smith, 2009). The OER had been a part of the education system since the advent of computer and internet technology around the 1990s. OER are “teaching, learning, and research materials in any medium – digital or otherwise – that reside in the public domain or have been released under an open license that permits no-cost access, use, adaptation, and redistribution by others with no or limited restrictions” (https:// hewlett.org/strategy/open-educational-resources/). There are numerous types of OER comprising course materials, full courses, modules, encyclopedias, text-books, games, lesson plans, syllabi, quizzes, instructional modules, model tests, assignments, practical modules, educational audios/videos, virtual field trips, virtual field experiences, and virtual science laboratories (Smith, 2009; Waldrop, 2013). In addition, the OER also contain rich teaching resources, including methods and tools of teaching that led to improved pedagogical skills, growth, and professional development of teachers. COVID-19 has had at least two impacts on higher geological education, firstly, the suspension of regular classroom teaching, and secondly, not allowing learners to undertake geological fieldwork in out-door environments because it involves moving learners between sites and use of public transport in groups. The loss of classroom teaching can be substituted by the use of online TLR, although the value of online TLR for particular courses or programs needs to be considered. However, geological fieldwork is one of the distinctive and compulsory components of both Bachelor’s and Master’s degree programs in Geology. It involves out-door visits of learners where they study rock outcrops exposed in their natural settings, for example, in quarries or mines, road cuttings, hilly and mountainous terrains, and along the river valleys. In the field, the learners carefully observe, record, and measure various geological features. Nature of Teaching-Learning Resources in Geology State University (Y) 171 134 78.36 37 21.64 Subtotal of TRL 776 592 76.29 184 23.71 Total of TRL 5029 4007 79.68 1022 20.32 COVID-19 pandemic and geological higher education: Challenges and opportunities COVID-19 pandemic and geological higher education: Challenges and opportunities Overall, data indicate that a majority of the TLR for higher education programs in Geology in India are of foreign origin. These resources are costly for learners and may or may not be sufficient to meet all content requirements of the various courses in the programs. Geology is a distinctive and field-based science discipline so a majority of its courses are based on the geological setting of the country. Therefore, the teaching-learning practice of such courses usually demands TLR of Indian origin (Wadia, 1916; Krishnan, 1949; Kumar, 2010; Mishra, 2016; Shah, 2018). The need to develop TLR of Indian origin taking the Indian geological setting into account has been highlighted by various workers (Wadia, 1919; Mishra, 2016; Kumar, 2010; Verma, 2017, 2018, 2019, 2021; Shah, 2018). The recent development of TLR in the form of MOOCs and modules of e-pgpathshala of the UGC are progressive steps taken to enrich TLR of the Indian origin for some Geology courses, but these resources are still meagre and need to be added extensively. The Corona virus disease 2019 (COVID-19) was declared a global pandemic by the World Health Organisation (WHO) in March 2020 (WHO, 2020) and recognized as a health, economic, and social crisis. It can be viewed as both a challenge and opportunity as far as geological education and research are concerned. Due to the COVID-19 outbreak, all educational institutions including schools, colleges, and universities in India were closed from 24th March 2020 due to lockdown implementation across the country by the GOI, which opened later on in a phased manner (https://www.mohfw.gov.in/). The months-long closure of educational institutions in 2020-2021 had stopped classroom teaching and thus, badly hampered teaching-learning processes whilst 247 Geological education scenario in India and role of open educational resources in the light of COVID-19 pandemic disengaging learners from active learning. It impacted the mental health of both learners and teachers. In order to provide uninterrupted learning to learners, the UGC and MHRD advised higher learning institutes to make extensive use of the ICT to deliver online higher education to learners (UGC, 2020). Nature of Teaching-Learning Resources in Geology It also advised learners to use the OER available on various online platforms such as Swayam online courses, e-pgpathshala, etc. to continue their learning. (b) if, it becomes impossible to arrange geological fieldwork in the coming two years due to travel restrictions because of the extended COVID-19 infection, what would be the best possible solution to the problem might be. OER and their role in geological higher education They learn to identify various rock-types, fossils, structural features (fold, faults, joints, unconformities), and techniques for collecting samples in the field (Lisle et al., 2011). In addition, they also learn how to measure dip, strike, and thickness of rock units and structural features, and how to document field data in field diaries. The overall purpose of geological fieldwork is to develop field-based geological skills and understanding in the learners (Lisle et al., 2011). As Geology is a field-based science, a degree without having field-related skills is of no value to learners. Therefore, learners of degree programs in Geology in one region of the country normally visit other regions to undertake geological fieldwork and develop sound field-based geological skills, often traveling distances of hundreds of kilometers. To summarize, the major challenges posed by COVID-19 to the geological teaching community are: (a) to evaluate whether the currently available online TLR are sufficient to meet the current and future demands or whether more TLRs are required, and There are several higher education organizations/societies around the world that have been developing OER in geological education and offering them free online in various formats like PDF, HTML, videos, etc. for the benefit of the global teaching-learning community (Table 4). Table 4. Name and web link of educational institutions and societies offering geological OER S.No. Name educational institution /society/ organization Web link of geological OER 1. Humboldt State University https://libguides.humboldt.edu/openedu/geol 2. University of Houston-Victoria https://library.uhv.edu/oer/geology 3. Washtenaw Community College https://libguides.wccnet.edu/oer-subjects/geology 4. Mt San Antonio College https://mtsac.libguides.com/oer/earth-science 5. University of Kentucky https://libguides.uky.edu/c.php?g=222941&p=6722485 6. Austin Community College https://researchguides.austincc.edu/c.php?g=434670&p=5818520 7. East Tennessee State University https://libraries.etsu.edu/research/guides/geosciences/oer 8. Salt Lake Community College https://opengeology.org/textbook/ 9. San Bernardino Valley College https://www.valleycollege.edu/open-education-resources/faculty/geology.php, 10. Creative Commons https://www.oercommons.org/browse?f.search=Geology 11. The Open University https://www.open.edu/openlearn/science-maths-technology/science/geology 12. University of Edinburgh https://open.ed.ac.uk/tag/geoscience/ 13. International Geoscience Education Organization http://www.igeoscied.org/teaching-resources/ 14. Geological Society https://www.geolsoc.org.uk/heresources 15. British Geological Survey https://www.bgs.ac.uk/discoveringGeology/newsAndEvents/links.html 16. US Geological Survey https://www.usgs.gov/science-support/osqi/yes/resources-teachers 17. Society of Vertebrate Palaeontology http://vertpaleo.org/What-is-Vertebrate-Paleontology/Resources-for- Educators-and-Students.aspx Table 4. Name and web link of educational institutions and societies offering geological OER 248 Omkar Verma, Manthena Prashanth, Roberto Greco, Ashu Khosla, Kulwant Singh Many higher learning institutes in India had both typed and handwritten specific-course-based study material uploaded on their websites to provide continuity of learning to their learners during the COVID-19 crisis. The GOI has previously noted the potential of OER to offer high-quality and equitable education across the country (GOI, 2009). Data collection and interpretation Data collection and interpretation A structured questionnaire was prepared to investigate the value of OER in higher geological education in India and their role in the COVID-19 response efforts. The questionnaire was divided into three parts: personal data, educational resources in geological education, and, the use and need of OER in the higher Indian geological education system. All questions of the questionnaire were simple, easy to understand, and consisted mainly of multiple-choice options with a few short answer types. Part A: Personal Data provided information regarding age, gender, educational qualification, profession, affiliation, teaching experience, and mode of teaching before the COVID-19 pandemic of the respondents. Part B: Use of Educational Resources in Geological Education was designed to get information from respondents about the TLR of Indian and foreign origin that they had been using before and during the COVID-19. Part C: OER contained questions related to familiarity of the OER to the faculty, changes in their use before and during the COVID-19, and their potential to meet the requirement of compulsory components (fieldwork and laboratory) of higher degree programs. Figure 6. Map of India showing the distribution of places and response numbers in parenthesis from where the completed questionnaires were received. OER and their role in geological higher education The COVID-19 crisis prompted the Geology teaching-learning community to appreciate the potential of OER in higher education. As a consequence, a few OER in Geology are available at the e-pgpathshala portal of the UGC (https://epgp.inflibnet.ac.in/). Laboratory experiments and fieldwork are very important components in the successful completion of any degree program of higher geological education. In this regard, OER consisting of laboratory experiments, virtual geological laboratories, virtual field experiences, and geological field modules can offer hands-on training to learners in geological education. For example, Google Earth images have been extensively used as resources for teaching geological principles as well as for mapping, identifying, and interpreting geological features since 2005 (Lisle, 2006; Monet & Greene, 2012). The Indian lithospheric plate contains numerous geological features notably; geomorphic, tectonic, structural, stratigraphic, and petrologic that can be examined by utilizing freely downloadable high-resolution satellite images from the Google Earth program (http://earth.google.com). OER consisting of geological virtual fieldwork and modules of field-specific problems based on Indian outcrops using images of Google Earth were being developed, through which learners of Bachelor’s and Master’s degree programs in Geology may complete their compulsory fieldwork-based assignments in the light of the COVID-19 outbreak. Figure 6. Map of India showing the distribution of places and response numbers in parenthesis from where the completed questionnaires were received. OER usefulness in higher geological education: OER usefulness in higher geological education: Part A: Personal Data The analyzed sample shows that out of the total sample number (n = 63), the majority (i.e. 81%) of respondents hold doctorate degrees (Ph.D.) and a small group of just 17% holds master’s degrees. 83% (52) of respondents were males and only 17% (11) were females. The mean age of respondents was 44 years. They had a wide range of teaching experience and had been working at various positions viz., assistant professors (51%), professors (19%), associate professors (6%), researchers (5%), and geoscientists (5%) in descending order. A majority of respondents were at the beginning or in the middle of their teaching career, as is apparent from their teaching experience statistics: 0-5 years (28%), 5-10 years (23%), 10-15 years (15%) and 15-20 years (15%). Two (3%) respondents were not involved in teaching and the remaining 61 (97%) were directly involved in Bachelor’s and/or Master’s level teaching. The consolidated list of all Indian universities was obtained from the website of the UGC (https://www.ugc.ac.in/#) and one by one, the websites of all the universities were visited to find whether or not the university had a Department of Geology/Applied Geology/Earth Science/Geological Sciences, and further e-mail addresses of the existing teaching faculty of the departments were collected. The questionnaire was prepared using the Google Forms service of Google Docs (https://www.google.com/forms/about/) and sent online to the collected e-mail addresses of almost all universities faculty of Geology in the entire country. Additionally, the questionnaire was also sent to the geological teaching faculty of Indian Institutes of Technology, Indian Institutes of Science Education and Research, a few geologists of the GSI, and the Indian Statistical Institute. The questionnaire was sent to a total of 790 people, from which, 63 responses were received covering almost all parts of the country (Fig. 6). The data was collected between July and October 2020. A majority of responses were complete and usable for interpretation. Part B: Educational resources in geological education, use of TLR of Indian and foreign origin before and during the COVID-19 Trends in use of Indian and foreign OER before and during the COVID-19 OER types Indian OER Foreign OER Before COVID-19 During COVID-19 Before COVID-19 During COVID-19 Open textbooks 79% 56% 66% 48% Online videos 67% 77% 69% 83% Online audios 12% 28% 26% 31% Online lesson plans 34% 30% 19% 26% Modules 24% 28% 24% 19% Complete courses 24% 16% 17% 12% MOOCs 29% 37% 22% 24% Practical modules 24% 16% 12% 17% Virtual science laboratory 16% 7% 12% 14% Virtual field trips 16% 8% 10% 10% Assignment for students 38% 38% 25% 21% Table 6. Trends in use of Indian and foreign OER before and during the COVID-19 The questionnaire tested the change in the usage of TLR for teaching before and during COVID-19 (Table 5). The data showed a significant decrease in the use of hand-written content, followed by real field trips and real science laboratory work. However, typed learning content continued to be used almost in the same way as it was used before and during COVID-19. During the pandemic, the use of online platforms increased significantly from 26% to 66%. Table 5. Kind and percentage of TLR used before and after the COVID-19 Kind of TLR Before COVID-19 During COVID-19 Hand written contents 61% 29% Typed contents 65% 66% Typed containing all learning requirements and plagiarism free with no copyright issue 47% 42% Real science laboratory activities 55% 6% Real field trips 69% 3% Online platforms like SWAYAM, e-pgpathshala, and other online platforms 26% 66% Table 5. Kind and percentage of TLR used before and after the COVID-19 Thematic analysis indicates that the respondents thought that virtual open laboratory and field-based manuals could enhance the practical and field skills of learners to a reasonable extent. In fact, they (35%) were also of the view that virtual field trips based on Google Earth programs and, identification and measurement of various geological features by using high-resolution images, was a good alternative for completing compulsory geological fieldwork assignment for learners during the COVID-19 pandemic; 48% believed this at least to some extent. As far as practical components of the curriculum of programs are concerned, 35% of respondents realized that open laboratory manuals and virtual open labs were a good alternative, whilst nearly 48% thought this alternative was useful to a certain extent only. Part B: Educational resources in geological education, use of TLR of Indian and foreign origin before and during the COVID-19 Part B: Educational resources in geological education, use of TLR of Indian and foreign origin before and during the COVID-19 Before the COVID-19 pandemic, a majority of respondents (84%) were involved in face-to-face teaching and a minor proportion was also involved in online teaching (16%). It is inferred that out of the 61 respondents who responded to this item, the institutes/universities of almost one-third of the respondents (27%) did not provide any support and training in shifting from face-to-face to online modes of teaching. However, the institutes/universities of the remaining respondents, who were involved in face-to-face teaching before the pandemic, did provide support and training in moving to online modes of teaching. Such institutions had the advantage of being able to provide undisrupted learning during the pandemic. We followed Braun & Clarke’s (2006) six-step approach for undertaking thematic analysis of questionnaires received that involves becoming familiar with data, generating initial codes, searching themes, reviewing themes, defining themes, and, finally, undertaking interpretation. 249 eological education scenario in India and role of open educational resources in the light of COVID-19 pandemic to 28% (Table 6). The use of online lesson plans and assignments for students remained almost the same. It was anticipated that there might have been an increase in the use of virtual field trips or virtual science lab OER, but this is not the case, at least not according to the data so far collected. This may reflect the non-availability of virtual field trips or virtual science lab OER of Indian origin. The respondents, in assessing the quality of the TLR, showed more positivity towards the foreign origin resources (62%) in terms of cost, quality and availability, in comparison to the Indian origin resources (38%). However, they were of the view that the TLR of Indian origin are slightly more comprehensible than that of foreign origin. They thought that more preference should be given to the TLR of Indian origin (75%) in comparison to those of foreign origin (67%). Moreover, the majority (77%) declared that they found some shortage in the TLR of Indian origin and almost all the respondents (94%) thought that more courses-based TLR incorporating Indian geological context are needed. Almost one-third (28%) of the respondents commented that the TLR of Indian origin are not up-to-date. Table 6. Part B: Educational resources in geological education, use of TLR of Indian and foreign origin before and during the COVID-19 A small group consisting of 11% of respondents were quite negative about the potential use of virtual open laboratory, open field-based manuals, and open virtual field trips based on Google Earth. Overall, 20% of respondents were enthusiastic about exploring all the possibilities of the OER related to field and laboratory components. Meanwhile, more than one-third of the respondents (37%) were positive about the availability of Indian origin OER for teaching Geology. 4. Conclusions They can play a critical role in offering high-quality and equitable education. The availability of these resources in higher geological education is poor and not sufficient to meet the current demands of the teaching-learning community of the country. The questionnaire data show that there is an urgent need for open educational resources in all branches of Geology especially focused on course-specific modules, open lab manuals, open field-based manuals, virtual field experiences, and virtual field trips based on the Google Earth program. The latter should be based on Indian geological contexts to provide effective teaching-learning practices in Geological education. Therefore, it is critical to design and develops more open educational resources in Geology to meet the current demand of the country in terms of indigenous learning as well as to face any future COVID-19-like challenges. COVID-19 has hit geological higher education badly by disrupting face- to-face teaching-learning processes and preventing learners from undertaking compulsory geological fieldwork assignments in their programs. In this context, Open Educational Resources, which are course-based or chapter-specific free digital resources available in various downloadable formats (like PDF), have provided a suitable option for providing undisrupted, online, and remote learning, in overcoming many of the educational challenges posed by the COVID-19 pandemic. Open educational resources policies are valued by the Government of India and many educational institutions are implementing them. f Beane, J. E., Turner, C. A., Hooper, P. R., Subbarao, K. V., & Walsh, J. N. (1986). Stratigraphy, composition and form of the Deccan basalts, Western Ghats, India. Bulletin of Volcanology, 48, 61–83. https://doi.org/10.1007/ BF01073513 They can play a critical role in offering high-quality and equitable education. The availability of these resources in higher geological education is poor and not sufficient to meet the current demands of the teaching-learning community of the country. The questionnaire data show that there is an urgent need for open educational resources in all branches of Geology especially focused on course-specific modules, open lab manuals, open field-based manuals, virtual field experiences, and virtual field trips based on the Google Earth program. The latter should be based on Indian geological contexts to provide effective teaching-learning practices in Geological education. Therefore, it is critical to design and develops more open educational resources in Geology to meet the current demand of the country in terms of indigenous learning as well as to face any future COVID-19-like challenges. Bhattacharya, B. B. (2016). 4. Conclusions Geological education and research are the basic building blocks of the socio-economic growth and development of any country. Geologically, India is a unique country, because of the huge amount of georesources it contains. The mineral resource richness of the country was first fully understood by the British East India Company in 1835. They established the world’s second- largest organization, the GSI, in 1851 in India, to prospect for mineral resources. After a long time gap, Geology emerged as an independent science education discipline in the 1890s as a by-product of the GSI development. In the early nineteenth century, only a few universities offered higher education degree programs in Geology. Then, the number of institutes offering higher education programs in Geology substantially expanded in the late nineteenth to the early twentieth century. However, Geology as a science discipline within higher education is still less popular than other science disciplines in India. Further, Indian higher education in Geology still relies on costly and less accessible teaching-learning resources. Ali, S., Shekhar, S., Chandrasekhar, T., Yadav, A. K., Arora, N. K., Kashyap, C. A., Bhattacharya, P., Rai, S. P., Pande, P., & Chandrasekharam, D. (2021). Influence of the water–sediment interaction on the major ions chemis- try and fluoride pollution in groundwater of the Older Alluvial Plains of Delhi, India. Journal of Earth System Science, 130(2), 1–16. https://doi. org/10.1007/s12040-021-01585-3 Ali, S., Thakur, S. K., Sarkar, A., & Shekhar, S. (2016). Worldwide contamination of water by fluoride. Environmental chemistry letters, 14(3), 291–315. https://doi.org/10.1007/s10311-016-0563-5 Ayala, F. J. (2008) Science, evolution, and creationism. Proceedings of the National Academy of Sciences of the United States of America, 105(1), 3–4. https:// doi.org/10.1073/pnas.0711608105 Babu, M. S. U., & Nautiyal, S. (2015). Historical issues and perspectives of land re- source management in India: a review. The Institute for Social and Eco- nomic Change, Bangalore. http://www.isec.ac.in/WP%20309%20-%20 Umesh%20Babu%20and%20Sunil%20 Nautiyal_final.pdf (last accessed April 2021) COVID-19 has hit geological higher education badly by disrupting face- to-face teaching-learning processes and preventing learners from undertaking compulsory geological fieldwork assignments in their programs. In this context, Open Educational Resources, which are course-based or chapter-specific free digital resources available in various downloadable formats (like PDF), have provided a suitable option for providing undisrupted, online, and remote learning, in overcoming many of the educational challenges posed by the COVID-19 pandemic. Open educational resources policies are valued by the Government of India and many educational institutions are implementing them. Part C: OER use before and during the COVID-19 The respondents reported that they were quite well informed about OER. Around 81% had heard about OER before the survey, and nearly 61% had previously used them in the teaching-learning process. They (79%) had informed their students about the existence of the OER, and more than half (65%) were familiar with the appropriate geological OER, while 63% were acquainted with the OER of Indian origin. A majority of respondents reported that they were aware of Indian OER offering online platforms such as Nptel (https://nptel.ac.in/), Swayam (https://swayam.gov.in/), e-pgpathshala (https:// epgp.inflibnet.ac.in/), and others. Additionally, they were also aware of several foreign geological OER offering online platforms. The data also revealed that respondents were using various types of OER such as open textbooks, educational audios and videos, lesson plans, modules, and practical modules both before and during the COVID-19 pandemic. The majority of respondents were of the view that OER could work well for learners pursuing Bachelor’s (70%) and even more, for Master’s (78%) degree programs in Geology. The majority of respondents (75%) thought that it is quite important to use OER of either Indian or foreign origin, where content is enriched with Indian geological examples. Almost two-thirds (65%) feel that learners would benefit through the use of OER and that they have great potential to contribute to equitable and high-quality geological education across the country. When they were asked through the questionnaire what they had planned for the completion of compulsory geological fieldwork assignment during the COVID-19 pandemic, almost one-third (31%) hoped to be able to carry out the fieldwork Even before the COVID-19 pandemic, there was a quite wide variety of OER that had been used in teaching-learning practice; the most commonly used were open textbooks and videos available online (Table 6). There was a slight decrease in the use of open textbooks during COVID-19 and an increase in the use of online audio and videos, especially of Indian origin increasing from 12% 250 Omkar Verma, Manthena Prashanth, Roberto Greco, Ashu Khosla, Kulwant Singh after the end of the COVID-19 pandemic, around 20% had no plan, and 10% would like to wait until the end of the pandemic, and in the meantime, they will use online resources. The remaining one-third (39%) planned to use the online training and virtual field geology programs available from professional organizations and webinars for this purpose. valuable views. We are highly thankful to Late Prof. C. Dedication To complete the laboratory component of the curriculum during the COVID-19 pandemic, around one-third (34%) plan to complete it after the end of the COVID-19 pandemic, almost another third (24%) plan to complete the laboratory component of the curriculum by maintaining social distancing, using precautionary measures, and calling students in small groups to the laboratory, 15% had no plan, and the remaining 27% will think about the use of OERs and online video demonstrations for completing the activity. The authors are pleased to dedicate this paper to Late Prof. Chris King. He was a Professor and Director of Earth Science Education Unit, Keele University, United Kingdom. Prof. King was deeply involved in the establishment and development of the International Geoscience Organization and in organizing the first International Conference in Geoscience Education. He was a great promoter of geological education across the globe and immensely contributed to the field of geological education by designing and developing several teaching-learning resources till his last breath. Finally, in the comment section of the questionnaire, respondents were of the view that Geology is a field-based science and geological fieldwork is therefore vital for imparting real field skills to the learners. However, OER, particularly course-specific, open lab manuals, open field-based manuals, virtual field experiences, and virtual field trips based on the Google Earth program related to the Indian geological context, should be developed in almost all branches of Geology. Overall, the questionnaire data indicates that OER will enhance understanding of Geology and increase the skill of the learners, which will reduce the paucity of TLR. Further, they will help in providing equitable and high-quality higher geological education and make geological education more flexible by providing a new teaching-learning experience with the potential to tackle any future COVID-19-like situation. Part C: OER use before and during the COVID-19 King for offering initial comments on the manuscript. The authors also sincerely thank five anonymous reviewers, Prof. M.A. Malik, and Prof. Alexander Caneva (Editor-in-Chief) for constructive criticism. 4. Conclusions Geoscience education – experiences and future pers- pective. In: K. Sain & A.S.S.S.R.S. Prasad (Editors). Geoscience for Sus- tainability. Indian Geophysical Union, National Geophysical Research Institute, Hyderabad, India, 14–15. Bisht, H., Rani, M., Kumar, K., Sah, S., & Arya, P. C. (2019). Retreating rate of Chaturangi glacier, Garhwal Himalaya, India derived from kinematic GPS survey and satellite data. Current Science, 1169(2), 304–311. DOI: 10.18520/cs/v116/i2/304-311 Biswas, S. K. (1982). Rift basins in western margin of India and their hydro- carbon prospects with special reference to Kutch Basin. American As- sociation of Petroleum Geologists Bulletin, 66, 1497–1513. https://doi. org/10.1306/2F919C1A-16CE-11D7-8645000102C1865D References Adam, D. (2020). Special report: the simulations driving the world’s response to COVID-19. Nature, 580, 316–318. https://doi.org/10.1038/d41586- 020-01003-6 Adams, F. D. (1938). The Birth and Development of the Geological Sciences. Wi- lliams and Wilkins, Baltimore. Ali, S., Fakhri, Y., Golbini, M., Thakur, S. K., Alinejad, A., Parseh, I., Shekhar, S., & Bhattacharya, P. (2009). Concentration of fluoride in groundwater of India: A systematic review, meta-analysis and risk assessment. Ground- water for Sustainable Development, 9, 100224. https://doi.org/10.1016/j. gsd.2019.100224 Acknowledgments Biswas, S. K. (1987). Regional tectonic framework, structure and evolution of the western marginal basins of India. Tectonophysics, 135, 307–327. https:// doi.org/10.1016/0040-1951(87)90115-6 The authors are highly thankful to the geological professionals (teachers and scientists) for their participation in the online survey and for offering their 251 Geological education scenario in India and role of open educational resources in the light of COVID-19 pandemic Grout, A. (1995). Geology and India, 1770-1851. A study in the methods and motivations of a colonial science. PhD dissertation, London University, London. Biswas, S. K., & Chauhan, G. (2021). The Kutch rift basin–potential location for a national geopark of India. A Monograph on Potential Geoparks of India. Indian National Trust for Art and Cultural Heritage (INTACH). New Delhi, 1–36. Häggquist, E., & Söderholm, P. (2015). The economic value of geological infor- mation: synthesis and directions for future research. Resources Policy, 43, 91–100. https://doi.org/10.1016/j.resourpol.2014.11.001 Braun, V., & Clarke, V. (2006). Using thematic analysis in psychology. Quali- tative Research in Psychology, 3, 77–101. http://dx.doi.org/10.1191/ 1478088706qp063oa Henderson, S., & Ostashewski, N. (2018). Barriers, incentives, and benefits of the open educational resources (OER) movement: An exploration into instructor perspectives. First Monday, 23(12). https://doi.org/10.5210/ fm.v23i12.9172 Chakraborty, A. R. (1970). Scatter of Indian geological documents in Indian and foreign journals. Annals of Library Science and Documentation, 17(1–2), 47–53. Howarth, R. J. (2020). Etymology in the earth sciences: from ‘Geologia’ to ‘Geos- cience’. Earth Sciences History, 39(1), 1–27. DOI: 10.17704/1944-6187- 39.1.1 Chakraborty, A. R. (1971). Early attempts of documentation of geological lite- rature in India- a review. Annals of Library Science and Documentation, 18, 132–140. Chakraborti, D., Das, B., & Murrill, M. T. (2011). Examining India’s groundwater quality management. Environmental Science & Technology, 45, 27–33. https://doi.org/10.1021/es101695d Huang, R., Liu, D., Tlili, A., Knyazeva, S., Chang, T. W., Zhang, X., Burgos, D., Jemni, M., Zhang, M., Zhuang, R., & Holotescu, C. (2020). Guidance on open educational practices during school closures: utilizing OER under COVID-19 pandemic in line with UNESCO OER recommendation. Smart Learning Institute of Beijing Normal University, Beijing.https:// iite.unesco.org/wp-content/uploads/2020/05/Guidance-on-Open-Edu- cational-Practices-during-School-Closures-English-Version-V1_0.pdf (last accessed April 2021) Chauhan, G., Biswas, S. K., Thakkar, M. G., & Page, K. N. (2021). The unique geoheritage of the Kachchh (Kutch) Basin, Western India, and its con- servation. Geoheritage,  13(1), 1–34. https://doi.org/10.1007/s12371- 021-00535-1 Courtillot, V. (1990). Deccan volcanism at the Cretaceous-Tertiary boundary: past climatic crises as a key to the future? Palaeogeography, Palaeocli- matology, Palaeoecology, 89(3), 291–299. Acknowledgments https://doi.org/10.1016/0921- 8181(90)90025-8 Indian National Trust for Art and Cultural Heritage. (2016). A monograph on national geoheritage monuments of India. Indian National Trust for Art and Cultural Heritage, Natural Heritage Division, New Delhi. http://na- turalheritage.intach.org/geoheritage-publications/ Das, P. K. (2015). The Monsoon. National Book Trust, New Delhi, India. Jain, A. K., Dasgupta, S., Bhargava, O. N., Israil, M., Perumal, R. J., Patel, R. C., Mukul, M., Parcha, S. K., Adlakha, V., Agarwal, K. K., Singh, P., Bha- ttacharyya, K., Pant, N. C., & Banerjee, D. M. (2016). Tectonics and evolution of the Himalaya. Proceedings of the Indian National Science Academy, 82(3), 581–604. Dimri, A. P., Yasunari, T. Y., Kotlia, B. S., Mohanty, U. C., & Sikka, D. R. (2016). Indian winter monsoon: Present and past. Earth-Science Review, 163, 297–322. https://doi.org/10.1016/j.earscirev.2016.10.008 Dolphin, G., Dutchak, A., Karchewski, B., & Cooper, J. (2019). Virtual field ex- periences in introductory geology: addressing a capacity problem, but finding a pedagogical one. Journal of Geoscience Education, 67(2), 114– 130. https://doi.org/10.1080/10899995.2018.1547034 Jain, V., & Sinha, R. (2005). Response of active tectonics on the alluvial Bagh- mati River, Himalayan foreland basin, eastern India. Geomorphology, 70(3–4), 339–356. https://doi.org/10.1016/j.geomorph.2005.02.012 Fareeduddin, Pant, N. C., Gupta, S., Chakraborty, P., Sensarma, S., Jain, A. K., Prasad, G. V. R., Srivastava, P., Rajan, S., & Tiwari, V. M., (2020). The geodynamic evolution of the Indian Subcontinent- An introduction. Episodes, 43(1), 7–18. https://doi.org/10.18814/epiiugs/2020/020001 Kania, S., Khosla, A., Verma, O., & Prashanth, M. (2022). Charophyte assembla- ge in the Cretaceous–Palaeogene boundary from Chhindwara District (Madhya Pradesh), Central India. Himalayan Geology, 43(2), 383–396. Khosla, A., Lucas, S. G., Kania, S., & Verma, O. (2022). Charophytes from the Cretaceous–Palaeogene transition in the Jhilmili intertrappean beds of Central India. Geological Journal, 1-27. https://doi.org/10.1002/gj.4528 Field, R. M. (1941). Geophysics and world affairs: a plea for geoscience. Eos, 22, 225–234. Fox, C. S. (1947). The Geological Survey of India, 1846 to 1947. Nature, 4078, 889–891. King, C. (2008). Geoscience education: an overview. Studies in Science Education, 44(2), 187–222. https://doi.org/10.1080/03057260802264289 Frodeman, R. (1995). Geological reasoning: geology as an interpretive and his- torical science. Geological Society of America Bulletin, 107(8), 960–968. King, C. (2018). Earth Science education across the globe. M.L.M., Hernandez (Editor). Geoscience in Primary and Secondary Education. United Na- tions Educational, Scientific and Cultural Organization, France, 16–33. Froude, M. J., & Petley, D. N. (2018). Global fatal landslide occurrence from 2004 to 2016. Natural Hazards and Earth System Sciences, 18, 2161–2181. https://doi.org/10.1111/j.1365-2451.2006.00546.x https://doi.org/10.1111/j.1365-2451.2006.00546.x Mora, G. (2013). The need for geologists in sustainable development. GSA Today, 23(12), 36–37. DOI: 10.1130/GSATG185GW.1 Lisle, R. J., Brabham, P., & Barnes, J. W. (2011). Basic Geological Mapping. John Wiley & Sons, Oxford. Mukherjee, S. (2019). Tectonics and Structural Geology: Indian Context. Springer Nature, Switzerland. Mandal, N. (2016). Current trends of geodynamic research in India: A review of theoretical and experimental studies. Proceedings of the Indian National Science Academy, 82(3), 425–434. Mukherjee, S., Misra, A. A., Calves, G., & Nemcok, M. (2016). Tectonics of the Deccan Large Igneous Province. Geological Society London Special Pu- blication, 445, 1–363. Manduca, C. A., & Kastens, K. A. (2012). Geoscience and geoscientists: uniquely equipped to study Earth. Geological Society of America Special Paper, 486, 1–12. https://doi.org/10.1130/2012.2486(01) Murty, K. S. (1979). History of geoscience information in India. In: A. P. Harvey & J. A. Diment (Eds.). Geoscience Information: A state-of-the art review. Proceedings of the 1st International Conference on Geological Informa- tion, London, 51–60. Mazumder, R., De, S., & Raju, P. V. S. (2019). Archean-Paleoproterozoic transition: The Indian perspective. In: R. Mazumder & P. Eriksson (Eds.). Archean Earth Processes. Earth Science-Review, 188, 427–440. https://doi.or- g/10.1016/j.earscirev.2018.11.013 Murty, K. S. (1982). Geological sciences in India in the 18th-19th century. Indian Journal of History of Science, 17(1), 164–178. Ministry of Human Resource Development Report. (2014). All India survey on higher education (2011-2012). Department of Higher Education, Mi- nistry of Human Resource Development, Government of India, New Delhi. https://mhrd.gov.in/sites/upload_files/mhrd/files/statistics-new/ AISHE2011-12.pdf (last accessed April 2021) Mythili, G., & Goedecke, J. (2016). Economics of land degradation in India. In: E. Nkonya, A. Mirzabaec, & J. von Braun. (Eds.). Economics of Land Degradation and Improvement – A Global Assessment for Sustainable Development, Springer, Cham, 431–469. Ministry of Human Resource Development Report. (2015a). All India survey on higher education (2012-2013). Department of Higher Education, Mi- nistry of Human Resource Development, Government of India, New Delhi. https://mhrd.gov.in/sites/upload_files/mhrd/files/statistics-new/ AISHE2012-13.pdf (last accessed April 2021) Nagendra, R., Kamalak Kannan, B. V., Sen, G., Gilbert, H., Reddy, A. N., & Jai- prakash, B. C. (2011). Sequence surfaces and paleobathymetric trends in Albian to Maastrichtian sediments of Ariyalur area, Cauvery Basin, India. Marine and Petroleum  Geology, 28(4), 895–905. https://doi.or- g/10.1016/j.marpetgeo.2010.04.002 Naqvi, S. M. (2005). Geology and Evolution of the Indian Plate (From Hadean to Holocene – 4 Ga to 4 Ka). Capital Publishing Company, New Delhi. Ministry of Human Resource Development Report. (2015b). Acknowledgments ht- tps://doi.org/10.5194/nhess-18-2161-2018 King, C. (2019). Exploring Geoscience Across the Globe. International Geos- cience Education Organization. http://www.igeoscied.org/wp-content/ uploads/2019/12/Geotextbook_Dec_2019.pdf (last accessed April 2021) Government of India (2009). National Knowledge Commission: report to the nation 2006-2009. National Knowledge Commission, Government of In- dia, New Delhi. Kölbl-Ebert, M. (2009). Geology and Religion: A History of Harmony and Hosti- lity. Geological Society London Special Publication, 310(1), 1–357. Government of India (2012). Report of the Committee for review and restructu- ring of the functions and role of the Indian Bureau of Mines. Ministry of Mines, Government of India. https://ibm.gov.in/index.php?c=pa- ges&m=index&id=366 (last accessed April 2021) Kouser, B., Bala, A., Verma, O., Prashanth, M., Khosla, A., & Pir, R. A. (2022). Hydrochemistry for the assessment of groundwater quality in the Ka- thua region, Jammu and Kashmir, India. Applied Water Science, 12:143. https://doi.org/10.1007/s13201-022-01673-9 GSA Position Statement (2016). Expanding and improving geoscience in hi- gher education. https://www.geosociety.org/documents/gsa/positions/ pos18_HigherEd.pdf (last accessed April 2021) Krishnan, M. S. (1949). Geology of India and Burma. The Madras Law Journal Office, Madras, India. Geological Survey of India (2011). Detailed information dossier on diamond in India. Geological Survey of India, Kolkata, India. https://employee.gsi. gov.in/cs/groups/public/documents/document/b3zp/mdyy/~edisp/ dcport1gsigovi062248.pdf (last accessed April 2021) Kumar, D. (1982). Economic compulsions and the Geological Survey of India. Indian Journal of History of Science, 17(2), 289–300. Kumar, D. (1995). Science and the Raj, 1857-1905. Oxford University Press, New Delhi. Kumar, R. (2010). Fundamentals of Historical Geology and Stratigraphy of In- dia. New Age International Publishers, New Delhi. 252 Omkar Verma, Manthena Prashanth, Roberto Greco, Ashu Khosla, Kulwant Singh Kumari, V., Tandon, S. K., Kumar, N., & Ghatak, A. 2020. Epicontinental Per- mian-Cretaceous seaways in central India: The debate for the Nar- mada versus Godavari rifts for the Cretaceous-Tertiary incursion. Earth-Science Reviews, 211, 103284. https://doi.org/10.1016/j.earsci- rev.2020.103284 Ministry of Human Resource Development Report. (2019). All India survey on higher education 2018-2019. Department of Higher Education, Ministry of Human Resource Development, Government of India, New Delhi. http://aishe.nic.in/aishe/viewDocument.action?documentId=262 (last accessed April 2021) Kundal, P., & Humane, S. K. (2007). Stratigraphic, paleobiogeograhic and paleoen- vironmental significance of Mesophyllum, a nongeniculate coralline alga from western Kachchh (Middle Eocene to Oligocene), India. In: D. K. Sin- ha (Editor). Micropaleontology: Application in Stratigraphy and Paleo- ceanography. Narosa Publishing House Pvt. Ltd., New Delhi, 145–154. Mishra, V. P. (2016). Geoscience education in India: framework and structure in a digital age. In: K. Sain & A.S.S.S.R.S. Prasad (Eds.). Geoscience for Sus- tainability. Acknowledgments Indian Geophysical Union, National Geophysical Research Institute, Hyderabad, India, 11-13. Mohanty, S. (2015). Precambrian continent assembly and dispersal events of South Indian and East Antarctic Shields. International Geology Review, 57(6), 1992–2027. https://doi.org/10.1080/00206814.2015.1048751 Larwood, H. J. G. (1958). Science in India before 1850. British Journal of Educa- tional Studies, 7(1), 36–49. Lisle, R. J. (2006). Google Earth: a new geological resource. Geology Today 22(1), 29–32. Monet, J., & Greene, T. (2012). Using Google earth and satellite imagery to foster place-based teaching in an introductory physical geology course. Jour- nal of Geoscience Education, 60, 10–20. https://doi.org/10.5408/10-203.1 https://doi.org/10.1111/j.1365-2451.2006.00546.x Prashanth, M., Kumar, A., Dhar, S., Verma, O., & Gogoi, K. (2022). Hypsome- tric analysis for determining erosion proneness of Dehar watershed, Himachal Himalaya, North India. Journal of Geosciences Research, 7(1), 86–94. https://doi.org/10.1016/j.pgeola.2017.01.002 Prashanth, M., & Verma, O. (2022). Medical geology: An interdisciplinary approach intended to unfold the issues of natural environment on pu- blic health. Journal of Geosciences Research, 7(2), 139–144. Stubblefield, C. J. (1970). Darashaw Nosherwan Wadia 1883-1969. Biographical Memoirs of Fellows of the Royal Society, 16, 542–562. Tandon, S. K. (2005). The science of the earth, and earth science education in India. Current Science, 88(4), 546–547. Press, F. (2008). Earth science and society. Nature, 451, 301–303. Rajendran, C. P. (2019). Shifting paradigms: why history matters in geological sciences. Current Science, 117(6), 927–931. DOI: 10.18520/cs/v117/ i6/927-931 Tandon, S. K. (2022). The Himalayan foreland basin- stratigraphic records of continent-to-continent collisional processes. Journal of the Geological Society of India, 98(7), 1015–1015. Rajendran, K., Parameswaran, R. M., & Rajendran, C. P. (2017). Seismotecto- nic perspectives on the Himalayan arc and contiguous areas: Inferences from past and recent earthquakes. Earth-Science Review, 173, 1–30. ht- tps://doi.org/10.1016/j.earscirev.2017.08.003 https://doi.org/10.1007/s12594-022-2110-2 Tandon, S. K., Pant, C. C., & Casshyap, S. M. (1991). Sedimentary Basins of India: Tectonic Context. Gnyanodaya Prakashan, Nainital, India. Tolman, A. B. (2016). Geologists and the British Raj, 1870-1910. All Graduate Theses and Dissertations. Department of History, Utah State University. https://digitalcommons.usu.edu/etd/4989 (last accessed April 2021) Raju, N. J. (2017). Prevalence of fluorosis in the fluoride enriched groundwater in semi-arid parts of eastern India: Geochemistry and health implications. Quaternary  International, 443, 265–278. https://doi.org/10.1016/j. quaint.2016.05.028 University Grant Commission. (2015a). Instructional template for facilitating implementation of Choice Based Credit System (CBCS) (Online). ht- tps://www.ugc.ac.in/pdfnews/4426331_Instructional-Template.pdf (last accessed April 2021) Radhakrishna, B. P. (2005). Relevance of geology. Journal of the Geological Socie- ty of India, 65, 531–536. Sabin, T. P., Krishnan, R, Vellore, R., Priya, P., Borgonkar, H. P., Singh, B. B., & Sagar, A. (2020). Climate change over the Himalayas. In: R. Krishnan, J. Sanjay, C. Gnanaseelan, M. Mujumdar, & A. Kulkarni (Eds.). Assess- ment of Climate Change over the Indian Region. Springer, Singapore, 207–222. University Grant Commission. (2015b). Syllabus for B.Sc. (Hons.) Geology Six Semester Course Under Choice Based Credit System. https://www.ugc. ac.in/pdfnews/1853907_B.Sc.-Hons.-Goelogy.pdf (last accessed April 2021) University Grant Commission. (2015c). Proposed syllabus and Scheme of Exa- mination for B.Sc. with Geology Under Choice Based Credit System. https://www.ugc.ac.in/pdfnews/7834290_B.Sc.-with-Geology.pdf (last accessed April 2021) Saha, D. (2016). https://doi.org/10.1111/j.1365-2451.2006.00546.x All India survey on higher education (2013-2014). Department of Higher Education, Mi- nistry of Human Resource Development, Government of India, New Delhi. https://mhrd.gov.in/sites/upload_files/mhrd/files/statistics-new/ AISHE2013-14.pdf (last accessed April 2021) Oldham, T. (1856). Memoir of the Geological Survey of India. Bengal Military Orphan Press, Calcutta, India, 1, 1–309. Padmanabhan, G. (2018). Why no geology at plus two? The Hindu News Paper (Online). https://www.thehindu.com/education/why-no-geology-in- plus-two/article23934680.ece (last accessed April 2021) Ministry of Human Resource Development Report. (2016a). All India survey on higher education (2014-2015). Department of Higher Education, Mi- nistry of Human Resource Development, Government of India, New Delhi. https://mhrd.gov.in/sites/upload_files/mhrd/files/statistics-new/ AISHE2014-15.pdf (last accessed April 2021) Pal, D. K., Bhattacharyya, T., Srivastava, P., Chandran, P., & Ray, S. K. (2009). Soils of the Indo-Gangetic plains: their historical perspective and ma- nagement. Current Science, 96, 1193–1202. Ministry of Human Resource Development Report. (2016b). All India survey on higher education (2015-2016). Department of Higher Education, Mi- nistry of Human Resource Development, Government of India, New Delhi. https://mhrd.gov.in/sites/upload_files/mhrd/files/statistics-new/ AISHE2015-16.pdf(last accessed April 2021) Palit, C. (2013). Symbiotic relation between geology and botany – Pramatha Nath Bose and Girish Chandra Bose. Indian Journal  of  History  of  Science, 48(3), 477–484. Paliwal, B. S. (2005). Geology introduced as an optional subject in schools in Rajasthan. Journal of the Geological Society of India, 66, 658. Ministry of Human Resource Development Report. (2017). All India survey on higher education (2016-2017). Department of Higher Education, Mi- nistry of Human Resource Development, Government of India, New Delhi. https://mhrd.gov.in/sites/upload_files/mhrd/files/statistics-new/ AISHE2016-17.pdf(last accessed April 2021) Parsons, A. J., Hosseini, K., Palin, R. M., & Sigloch, K. (2020). Geological, geophy- sical and plate kinematic constraints for models of the India-Asia colli- sion and the post-Triassic central Tethys oceans. Earth-Science Review, 208(103084), 1–63. https://doi.org/10.1016/j.earscirev.2020.103084 Ministry of Human Resource Development Report. (2018). All India survey on higher education 2017-2018. Department of Higher Education, Ministry of Human Resource Development, Government of India, New Delhi. https://mhrd.gov.in/sites/upload_files/mhrd/files/statistics-new/AI- SHE2017-18.pdf (last accessed April 2021) Prashanth, M., Kumar, A., Dhar, S., Verma, O., & Sharma, S. (2021). Morphome- tric characterization and prioritization of sub-watersheds for assessing soil erosion susceptibility in the Dehar watershed (Himachal Himala- ya), Northern India. Himalayan Geology, 42(2), 345–358. 253 Geological education scenario in India and role of open educational resources in the light of COVID-19 pandemic Stewart, I. S., & Gill, J. C. (2017). Social geology — integrating sustainability concepts into Earth sciences. Proceedings of the Geologists’ Association, 128(2), 165–172. https://doi.org/10.1111/j.1365-2451.2006.00546.x Course curriculum in geology and quality of geoscience education in India. In: K. Sain, & A.S.S.S.R.S. Prasad (Eds.). Geoscience for Sus- tainability. Indian Geophysical Union, National Geophysical Research Institute, Hyderabad, India, 8–10. University Grant Commission. (2019). Learning Outcomes based Curriculum Framework (LOCF) for Undergraduate Programme B.Sc. (Geology). https://www.ugc.ac.in/pdfnews/4480737_Geology.pdf (last accessed April 2021) Saha, D. (2018). Woes of geoscience education in India. Current Science, 115(4), 595–596. https://doi.org/10.18520/cs%2Fv115%2Fi4%2F595-596 Saha, D., Shekhar, S., Ali, S., Elango, L., & Vittala, S. (2020). Recent scientific perspectives on the Indian hydrogeology. Proceedings of the Indian Na- tional Science Academy, 86(1), 459–478. University Grant Commission. (2020). Let COVID 19 not stop you from lear- ning- ICT initiatives of MHRD and UGC. https://www.ugc.ac.in/pdf- news/1573010_On-Line-Learning---ICT-initiatives-of-MHRD-and- UGC.pdf (last accessed April 2021) Santosh, M. (2012). India’s Palaeoproterozoic legacy. In: R. Mazumder & D. Saha (Eds.). Palaeoproterozoic of India. Geological Society London Special Pu- blication, 263–288. United Nations (2015). Sustainable Development Goals (Online). http://www.un.org/sustainabledevelopment/sustainable-development-goals/. (last accessed April 2021) Searle, M. P., & Treloar, P. J. (2019). Introduction to Himalayan tectonics: a mo- dern synthesis. Geological Society London Special Publication, 483, 1–17. https://doi.org/10.1144/SP483-2019-20 Valdiya, K. S. (2016). The Making of India: Geodynamic Evolution. Springer In- ternational Publishing, Switzerland. Shah, S. K. (2018). Historical Geology of India. Scientific Publishers, Jodhpur, In- dia. Verma, O. (2015). Cretaceous vertebrate fauna of the Cauvery Basin, southern India: palaeodiversity and palaeobiogeographic implications. Palaeo- geography, Palaeoclimatology, Palaeoecology, 431, 53–67. Shalley, M. J. (1971). The role of geology and geophysics in mineral exploration. Exploration Geophysics, 2(2), 38–44. Verma, O. (2017). Elements of Palaeontology. Current Science, 113(10), 2037. Verma, O. (2017). Elements of Palaeontology. Current Science, Shekhar, S., Kumar, P., Chauhan, G., & Thakkar, M. G. (2019). Conservation and sustainable development of geoheritage, geopark, and geotourism: a case study of Cenozoic successions of Western Kutch, India. Geoherita- ge, 11(4), 1475–1488. https://doi.org/10.1007/s12371-019-00362-5 Verma, O. (2018) Paleoecology: Past, Present and Future. Journal of the Geolo- gical Society of India, 91(1): 115–116. https://doi.org/10.1007/s12594- 018-0843-8 Verma, O. (2019). Historical Geology of India. Journal of the Palaeontological Society of India, 64(1), 43–145. Sheth, H. C. (2007). ‘Large Igneous Provinces (LIPs)’: Definition, recommen- ded terminology, and a hierarchical classification. Earth-Science Review, 85(3–4), 117–124. Verma, O. (2021). Role of open educational resources to support higher geos- cience education in India. Journal of Geosciences Research, 6(1), 1–10. https://doi.org/10.1016/j.earscirev.2007.07.005 Verma, O., & Khosla, A. (2019) Developments in the stratigraphy of the Dec- can Volcanic Province, peninsular India. Comptes Rendus Geoscience, 351(7), 461–476. https://doi.org/10.1016/j.crte.2019.10.002 Sharma, K. K. (1998). Geologic and tectonic evolution of the Himalaya before and after the India-Asia collision. Proceedings of the Indian Academy of Sciences (Earth and Planetary Sciences), 107(4), 265–282. Smith, M. S. (2009). Opening education. Science, 323, 89–93. 254 Omkar Verma, Manthena Prashanth, Roberto Greco, Ashu Khosla, Kulwant Singh Waldrop, M. M. (2013). Education online: The virtual lab. Nature, 499, 268–270. https://doi.org/10.1038/499268a Verma, O., Khosla, A., Goin, F. J., & Kaur, J. (2016). Historical biogeography of the Late Cretaceous vertebrates of India: comparison of geophysical and paleontological data. New Mexico Museum of Natural History and Scien- ce Bulletin, 71, 317–330. World Health Organization (2020). Coronavirus disease (COVID-19) pan- demic. https://www.who.int/emergencies/diseases/novel-coronavi- rus-2019 (last accessed April 2021) Wadia, D. N. (1919). Geology of India. Macmillan and Co., London. Wilson, A. (1883). Facts and fictions of zoology. The World’s Cyclopedia of Science. J.B. Alden, New York. 1, 207–272. Wadia, D. N. (1964). Progress of geology. Journal of the Geological Society of In- dia, 5, 1–4. Wagh, S. (2018). The British rule and its impact on India. Atharva Publications, Maharashtra, India.
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Design and Performance Investigation of a New Distributed Amplifier Architecture for 40 and 100 Gb/s Optical Receivers
International journal of computer and technology
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ISSN 2277-3061 Design and Performance Investigation of a New Distributed Amplifier Architecture for 40 and 100 Gb/s Optical Receivers Essra E. Al-Bayati, R. S. Fyath Department of Electronic and Communications Engineering, Al-Nahrain University, Baghdad, Iraq. Email: eema_87@yahoo.com Department of Computer Engineering, Al-Nahrain University, Baghdad, Iraq. Email: rsfyath@yahoo.com ABSTRACT The design of distributed amplifiers (DAs) is one of the challenging aspects in emerging ultra high bit rate optical communication systems. This is especially important when implementation in submicron silicon complementary metal oxide semiconductor (CMOS) process is considered. This work presents a novel design scheme for DAs suitable for frontend amplification in 40 and 100 Gb/s optical receivers. The goal is to achieve high flat gain and low noise figure (NF) over the ultra wideband operating bandwidth (BW). The design scheme combines shifted second tire (SST) matrix configuration with cascode amplification cell configuration and uses m-derived technique. Performance investigation of the proposed DA architecture is carried out and the results are compared with that of other DA architectures reported in the literature. The investigation covers the gain and NF spectra when the DAs are implemented in 180, 130, 90, 65 and 45 CMOS standards.The simulation results reveal that the proposed DA architecture offers the highest gain with highest degree of flatness and low NF when compared with other DA configurations. Gain-BW products of 42772 and 21137 GHz are achieved when the amplifier is designed for 40 and 100 Gb/s operation, respectively, using 45 nm CMOS standard. The simulation is performed using AWR Microwave Office (version 10). Indexing terms/Keywords Distributed Amplifier; 40Gb/s Distributed amplifier; 100Gb/s Distributed amplifier Academic Discipline And Sub-Disciplines Electronics and Commun iocation Engineering- Optical Communications TYPE (METHOD/APPROACH) Anaylisis and Simulation Council for Innovative Research Peer Review Research Publishing System Journal: INTERNATIONAL JOURNAL OF COMPUTERS & TECHNOLOGY Vol 14 . No. 5 www.ijctonline.com , editorijctonline@gmail.com 5661 | P a g e Februarury 28, 2015 ISSN 2277-3061 1- INTRODUCTION Everybody wants to benefit from the evaluation in the field of communication especially through internet. Due to the expanding demand of communication services, the volume of data exchanged in the communication systems has increased. This leads to increase data rate of the global communication systems from tens of Gb/s to Tb/s. BW requirements will increase by more than 100 times and applications such as virtual reality require data rate that are 10,000 times higher than currently available. To transport such data rate, a media with low loss and high BW is required [1, 2]. Among the available medium to transfer the data, optical fibers have the best performance. Optical fibers are very common these days to transport very high rate digital data. Such high speed data rates can be transported over kilometers of optical fiber and without significant loss. Normally loss is very low when the signal is transmitted using light rather than electrical signal. These fibers also have the advantage of being low cost in addition to improvement of performance. Fiber optic devices and systems are evidently employed to realize very high data rates. Fiber optic communication is a solution because high data rates can be transmitted through this high capacity cable with high performance [3]. The exponential growth of Internet traffic is fueling the research and development of wavelength division multiplexed passive optical network technology in the access network segment [4]. Driven by the continues increase in BW demand and number of subscribers, future access networks will require 40 Gb/s high speed service per wavelength channel [5, 6] on a 50 GHz dense wavelength grid. The realization of high-speed analog-to-digital conversation and digital signal processing have enabled a bit rate of 100 Gb/s in long-haul coherent optical communication system [7]. However, for short-reach 100 Gb/s applications, solutions that use intensity modulation and direction detection are seen as more practical [8]. With the advances in semiconductor technologies, integrated circuits operating at 40 Gb/s have been realized in standard CMOS process [9]. Among all kinds of high speed circuits, the broadband amplifier is a key building block at both the transmitting and receiving ends, see Fig. 1. In fact there is demand for wideband CMOS amplifiers in the frontend section of the optical receivers. Distributed amplification is one of the well-known methods to provide such performance by absorbing the parasitic capacitances of parallel gain distributed cell into an artificial transmission line, which in return, guarantees the gain uniformity and input/output matching within the BW of operation. However, design DA for 40 Gb/s (and above) optical receivers needs careful consideration related to the gain, frequency spectrum and NF.This paper addresses the design issues and performance investigation of CMOS DA for the front-end amplification stage in 40 and 100 Gb/s optical receivers. Figure 1: Optical communication system [10]. 2- RELATED WORK In 2005, Wolf et al [11] demonstrated an eight-stage DA with 12.5 dB ± 0.45 dB gain and 50 GHz BW in a commercially available 0.1 μm metamorphic GaAs HEMT technology. The amplifier has a minimum NF lower than 2.5 dB in the BW. The group delay variation from 9 to 40 GHz is ± 7.5 ps and circuit power consumption is 0.4 W. Such amplifier packaged with a high responsively PD into a fiber pig-tailed module. Eye diagrams measurements demonstrate the successful highspeed operation of the photoreceiver. In 2007, Chien and Lu [12] presented a novel circuit topology for high-gain 40 Gb/s DAs. Based on the conventional distributed architecture, the gain cells were realized by cascading cascode stages for gain enhancement. In addition, the stagger-tuning technique was extensively utilized in the design of the cascode stages as well as the cascaded stages, leading to significant improvement in terms of the operating BW and the gain flatness. With the proposed circuit architecture, two amplifiers were implemented in a standard 180 nm CMOS technology. The amplifier with a 3 x3 configuration exhibits a gain of 16.2 dB and a 3 dB BW of 33.4 GHz, while the one in a form of 2x4 demonstrates a gain of 5662 | P a g e Februarury 28, 2015 ISSN 2277-3061 20 dB and a BW of 39.4 GHz. Consuming a DC power of 260 mW from a 2.8-V supply voltage, both circuits provide clear eye-opening with a pseudorandom bit sequence at 40 Gb/s. In 2009, Moez and Elmasry [13] presented a circuit technique to compensate for the metal and substrate loss of the onchip transmission lines, and, consequently, to improve the gain flatness and BW of CMOS DAs for optical receivers. An eight-stage DA suitable for 40 Gb/s optical communication was devised and implemented in a 130 nm CMOS process. The DA achieves a flat gain of 10 dB from DC to 44 GHz with an input and output matching better than −8 dB. The measured NF varies from 2.5 to 7.5 dB with the amplifier‟s band. The proposed DA dissipates 103mW from two 1-V and 1.2-V DC supplies. In 2009, Entesari et al [14] presented a state-of-the-art DA with coupled inductors in the gate line. The proposed coupled inductors, in conjunction with series-peaking inductors in cascode gain stages, provide BW extension with flat gain response for the amplifier without any additional power consumption. On the other hand, gate-inductor coupling improves the input matching of the amplifier considerably. The detailed analysis and design methodology for the proposed DA were presented. The new four-stage DA, fabricated using an IBM 0.18- m CMOS process, achieves a power gain of around 10 dB, input and output return losses better than 16 and 18 dB, respectively, a NF of 3.6–4.9 dB, and a power consumption of 21mW over a 16-GHz flat 1-dB BW. is between 0.1 and 3.75 dBm across the entire band. In 2010, Ghadiri and Moez [15] presented a new high-gain structure for DA. Negative capacitance cells were exploited to ameliorate the loading effects of parasitic capacitors of gain cells in order to improve the gain of the DA while keeping the desired BW. In addition, the negative capacitance circuit creates a negative resistance that can be used to increase the amplifier BW. Implemented in 130 nm IBM‟s CMRF8SF CMOS, the proposed six-stage DA presents an average gain of 13.2 dB over a BW of 29.4 GHz. The measured input return loss is less than 9 dB and the output return loss is less than 9.5 dB over the entire BW. With a chip area of 1.5 mm X 0.8 mm, the amplifier consumes 136 mW from a 1.5-V DC power supply. In 2010, Chien et al [16] presented a transimpedance amplifier (TIA) with a tunable BW for optical communications. The proposed TIA is composed of two cascaded stages in which an input network with inductive peaking elements is employed in the first stage for broadband operations while a modified DA is utilized as the second stage for enhanced transimpedance gain. In addition, a feedback loop is incorporated as the bandwidth-tuning mechanism. By tuning the BW of the TIA, optimum circuit operation with lowest bit error rate (BER) can be achieved in the receiver front end for highspeed data transmission. The proposed circuit was implemented in a 180 nm CMOS process. Consuming a DC power of 33.3 mW from a 1.8-V supply, the fabricated TIA exhibits a transimpedance gain of 47.8 dB and a variable 3-dB BW from 6.2 to 10.5 GHz. Providing a -1 pseudorandombit sequence at 9-15 Gb/s, a BER less than was demonstrated experimentally by the TIA with the BW tuning mechanism. In 2011, KimandBuckwalter [17] demonstrated a low-power cascode DA in a 45 nm silicon-on-insulator (SOI) CMOS process. The amplifier achieves a 3 dB BW of 92 GHz. The peak gain is 9 dB with a gain-ripple of less 1.5 dB over the BW. The group-delay variation is under ± 4.7ps over the 3 dB BW. The amplifier consumes 73.5mW from a 1.2V supply and results in a GBW efficiency figure of merit of 3.53 GHz/mW. The chip occupies an area of 0.45 including the pads. In 2012, Jahanian and Heydari [18] presented a CMOS DA with distributed active input balun that achieves a GBW product of 818 GHz, while improving linearity. Each cell within the DA employs dual-output two-stage topology that improves gain and linearity without adversely affecting BW and power. Comprehensive analysis and simulations were carried out to investigate gain, BW, linearity, noise, and stability of the proposed cell, and compare them with conventional cells. Fabricated in a 65-nm low-power CMOS process, the 0.9-mm DA achieves 22 dB of gain and a P1dB of 10 dBm, while consuming DC power of 97 mW from a 1.3-V supply. A distributed balun, designed and fabricated in the same process, using the same topology achieves a BW larger than 70 GHz and a gain of 4 dB with 19.5-mW power consumption from 1.3-V supply. In 2013, Feng et al [19] realized compact self-biased wideband low noise amplifier (LNA) in Global Foundries 65 nm CMOS technology. Wideband input matching characteristic is achieved by placing a series gate inductor and a parallel tuning capacitor in the resistive-feedback network. Combined with the inductive-series peaking technique which further extends the BW, the proposed cascaded three-stage resistive-feedback amplifier obtains a large operating BW which is comparable with the DA. Measurement shows that the proposed amplifier achieves a power gain of with input and output return losses better than 8 dB and NF ranging from 4.5 to 6.8 dB between 2.1–39 GHz. The fabricated low LNA occupies a silicon area of 0.16 including all testing pads and draws 17 mA from a 1.5 V power supply. In 2013, Kao et al. [20] proposed a new DA topology which is a combination of the conventional DA and the cascaded single-stage DA. This DA topology can provide wide BW with considerations of the gain, NF, and output power simultaneously, and requires reasonable DC power consumption. Two termination methods of this combination were investigated. From the measurements, the first DA has a small-signal gain of 20.5 dB, a 3-dB BW of 35 GHz, and a GBW product of 371 GHz. The maximum output power at 1-dB output compression point is 8.6 dBm and the NF is between 6.8– 8 dB at frequencies lower than 18 GHz. The chip size, including testing pads, is only 0.78 mm, and the ratio of the GBW to chip size is 476GHz/mm. The second DA has a small-signal gain of 24dB, a 3-dB BW of 33 GHz, and a GBW product of 523 GHz. The maximum output power is 9 dBm and the NF is between 6.5-7.5 dB at frequencies lower than 18 GHz. The chip size including testing pads is only 0.83 mm, and the ratio of the GBW to chip size is 630 GHz mm. 5663 | P a g e Februarury 28, 2015 ISSN 2277-3061 In 2013, Cho et al. [21] proposed a wideband switchless bi-directional DA in a commercial 130 nm CMOS technology, which realizes multi-octave BW with high gain and low NF using DA technique and cascode amplifier pair. The measured gain is over 10 dB and measured NF is 3.2-6.5 dB. The input and output return losses are better than 9 dB at 3–20 GHz. The measured output power 1dB and output input power (OIP3) is larger than 8 dBm and 17 dBm at 4–15 GHz. The chip sizeis 0.96 x 0.85 including pads. The proposed switchless bi-directional amplifier has almost the same chip size compared to the conventional uni-directional DA. In 2014, Kim and Nguyen [22] presented a new tri-band power amplifier on a 180 nm SiGeBiCMOS process, operating concurrently in Ku/K/Ka and -band, is presented. The concurrent tri-band PA design is based on the DA structure with capacitive coupling to enable large device size, while maintaining wide BW, gain cells with the enhanced-gain peaking inductor, and negative-resistance active notch filters for improved tri-band gain response. The concurrent tri-band PA exhibits measured small-signal gain around 15.4, 14.7 and 12.3 dB in the low band (10–19 GHz), midband (23–29 GHz), and high band (33–40 GHz), respectively. It is clear from the above survey that the reported designs of DAs suitable for high bit rate optical receiver don‟t achieves simultaneously wide BW, high flat gain and low NF. This issue is addressed in this thesis where a modified DA topology is introduced to reach these goals. 3- PROPOSED DA ARCITECTURE AND DESIGN CONCEPTS In the literature, different DA architectures have been discussed. Each one has its own design topology and uses different techniques to enhance one of the design requirements: wide BW, high flat gain and low NF. In this section, a new DA architecture is proposed to achieve ultrawide band operation under high amplification gain and low NF conditions. The proposed architecture collects the main features behind different topologies and techniques adopted in previous DA designs such as shifted second stage (SST) topology, matrix configuration, cascode cell amplifier configuration, and mderived matching technique. Design issues based on deep submicron CMOS technology are discussed toward achieving efficient front-end amplification in 40 Gb/s and 100 Gb/s optical receivers. 3.1 - Architecture of the Proposed Distributed Amplifier The main idea behind the proposed DA is to combine high-feature topologies and techniques adopted by other DA designs. The task in this work is primarily to design CMOS-based DA with ultrawide BW, high flat gain and low NF suitable for high bit rate optical receivers ( 40 Gb/s). The proposed DA uses the following techniques and topologies a- m-derived technique m-derived techniques is used at the input and output of constant-k filter sections in order to obtain flat BW and constant impedance matching. b- Shifted-Second Tire Matrix Configuration This type of DA uses additive and multiplicative technique to achieve high flat gain. The configuration uses M stages and N distributed cells (N tires). Simulation results show that design the DA with two stages and four distributed cells is sufficient to get the require design target. Using M>2 and N>4 will increase the complexity of the design without offering reasonable performance improvement. c- Cascode Amplification Cell Configuration Cascode DA is obtained by adding common-gate amplifier section to the drain line of common-source amplifier stage. Using cascode amplification cells in DA configuration will decrease the variation of the capacitance seen by the transmission line and offer a nearly flat gain over wider BW as compared with the simple common-source amplifier. The cascode amplifier can be considered as a two-stage amplifier composed of a transconductance amplifier followed by a current buffer [23]. Compared to a single amplifier stage, this combination may have one or more of the following characteristics: higher input-output isolation, higher input impedance, higher output impedance, higher gain or higher BW. Thus cascade configuration can be designed to improve input-output isolation (or reverse transmission) as there is no direct coupling from the output to the input. Fig. 2a shows a MOSFET cascode amplifier. If one make a small-signal analysis for this amplifier using the simplified small-signal equivalent circuit shown in Fig. 2b, the following results are obtained [23]. The voltage gain =-( 5664 | P a g e ) (1.a) Februarury 28, 2015 ISSN 2277-3061 (a) (b) Figure 2: a- Cascode MOSFET amplifier b- Simplified small-signal equivalent circuit of MOSFET [23]. ≈ when >>1 (1.b) Note that the cascode amplifier behaves as a common-source amplifier with higher gain. If identical transistor is used, the ≈ . The input resistance of the cascode amplifier tends to infinitely since the input signal source is applied to the high impedance gate terminal. The output resistance of the cascode amplifier is given by (2.a) For identical transistors (2.b) ≈ when >>2. This yields higher output impedance compared with conventional common-source amplifier. Fig. 3 shows a block diagram for the proposed DA configuration. The structure contains two amplification stages each with four amplification cells. The corresponding circuit-level description of the proposed DA is illustrated in Fig. 4. Figure 3: Block diagram of the proposed shifted second tier with m-derived DA. 5665 | P a g e Februarury 28, 2015 ISSN 2277-3061 3.2- Design Concepts The gate and drain transmission lines are designed with equal inductance and capacitance to ensure equal wave propagation velocities along both lines. The cutoff frequency and characteristic impedance of the transmission lines are given by = = = = = (3.a) = (3.b) where L and C stand, respectively, to the inductance and capacitance of the transmission line, while the subscripts g and d denote gate and drain, respectively. For given values of and , the transmission line elements can be calculated as follows = = (4.a) = = (4.b) Figure 4: Circuit-level description of the proposed DA having two stages each with four amplifications cells with m-drive techniques. 5666 | P a g e Februarury 28, 2015 ISSN 2277-3061 Note that both capacitance and inductance are inversely proportional to the cutoff frequency . This is illustrated in Figs. 5 a and b which show respectively, the dependence of = and = on the transmission line cutoff frequency when =50 Ω. At nH for =10 GHz, = = 0.63 pF and = nH. These values are to be compared with 0.08 pF and 0.19 =80 GHz. (a) (b) Figure 5: Dependence of the transmission line capacitance (a) and inductance (b) on the cutoff frequency. The next step is to determine transistor gate width for different submicron CMOS standards. The gate length (channel length) L is set equal to the used CMOS standard [24].The gate width is estimated using the following relation. = WL (5) W= (6.a) W= (6.b) where is the oxide capacitance per unit area. Unfortunately, values of for submicron CMOS standards used in this thesis <180 nm are not reported in the literature. For example, Ref. [25] gives for CMOS standards 800, 500, 250 and 180 nm (see Table 1). These data are curve fitted to the flowing equation = where + + (7) is the CMOS standard in nm. The values of the fitting coefficients are = 0.017188 = -25.876 5667 | P a g e Februarury 28, 2015 ISSN 2277-3061 = 12084 Fig. 6 shows the variation of with CMOS standard. The marks are the data taken for Ref. [25] while the solid line denotes curve fitting. The curve fitting is used to extract for CMOS standards 130, 90, 65 and 45 nm (see Table 1 and Fig. 7). Table 1: Oxide Capacitance CMOSStandard (nm) 800 ( for various CMOS standards. OxideCapacitance 2300 ) Referenc es [25] 500 3800 [25] 250 5800 [25] 180 8600 [25] 130 9001 This work 90 9089 This work 65 45 10005 11000 This work This work Figure 6: Variation of oxide capacitance with CMOS standard (>180 nm) Figure 7: Extracted values of oxide capacitance for 130, 90, 65 and 45 nm standards It is clear from Table 1 and Figs. 6 and 7 that increases as CMOS standard increases. This result can be explained by treating the gate capacitance simply as a two-parallel plate capacitance arises from the dioxide layer. 5668 | P a g e Februarury 28, 2015 ISSN 2277-3061 = (8.a) = = (8.b) =3.9 =3.45 x F/m where is the gate area and is the permittivity of the sillicon oxide which has decreases, thickness decreases too and leading to higher values for . thickness. As CMOS standard The dependence of the gate width on the cutoff frequency of the transmission line is reflected in Equ. 6b. For a given CMOS standard, the gate width is inversely proportional to the cutoff frequency. This relation is illustrated graphically in Fig. 8 where the gate width is plotted versus cutoff frequency for different values of CMOS standards. According to Equ. 6b, W Increases as CMOS standard decreases. Figure 8: Dependence of gate width on transmission line cutoff frequency for different CMOS standards. The next design step is to calculate the transistor transconductance as a function of transmission line cutoff frequency for different values of CMOS standards. Recall that =( ) when the transistor operates in the saturation region. Here is the electron mobility in the channel (assuming NMOS structure) and is the over drive voltage which is set to 0.2V in the simulation. With the aid of Equ. 6b one can arrive to the following expression for the transconductance = (9) Investigating Equ. 9 reveals the following findings I. is independent of oxide capacitance and gate width II. is inversely proportion to both cutoff frequency . and the square of the gate length. The electron mobility for NMOS transistors fabricated with standards 180 nm and above are reported in Ref. [25] and listed in Table 2. These data is curve fitted to the following polynomial in order to extract the values of for standards below 180 nm (see Fig. 9) = where + in + / / b2= 1.7265 x / b1= 0.14487 b0= 423.09 5669 | P a g e (10) / Februarury 28, 2015 ISSN 2277-3061 The extracted values of for standards 130, 90, 65 and 45 nm are listed in Table 2. Table 2: Electron mobility for various CMOS standards. CMOS Standard (nm) Electron Mobility ( Reference ) 800 550 [25] 500 500 [25] 250 460 [25] 180 450 [25] 130 442 This work 90 436 This work 65 433 This work 45 430 This work Figure 9: Variation of electron mobility with CMOS standard. Figs. 10 a-e show the variation of transconductance with transmission line cutoff frequency for different CMOS standards 180, 130, 90, 65 and 45 nm, respectively. Note that increases rapidly as the fabrication process goes to a smaller standard. This result is expected since is inversely proportional to and the gate length L decreases as one dopted deeper submicron standards. For example, the values of at = 40 GHz are 0.053S, 0.124S, 0.256S, 0.488S and 1.012S for 180, 130, 90, 65 and 45 nm standards, respectively. Table 3 lists the required transistor design parameters (L, W and ) for NMOS transistor fabricated using deep submicron standards and operates at a specific value of cutoff frequency . 5670 | P a g e Februarury 28, 2015 ISSN 2277-3061 Figuer 10: Dependence of NMOS transconductance with transmission line cutoff frequency for different standards. (a) 180 nm, (b) 130 nm, (c) 90 nm, (d) 65 nm, (e) 45 nm. 5671 | P a g e Februarury 28, 2015 ISSN 2277-3061 Table 3: NMOS transistor parameters for different values of cutoff frequency and fabrication standards. Standard (nm) 180 Transistor Parameter 80 180 180 W (µm) 270 138 87 69 0.104 0.053 0.033 0.026 L (nm) 130 130 130 130 W (µm) 396 203 128 101 0.243 0.124 0.078 0.062 L (nm) 90 90 90 90 W (µm) 522 267 168 134 0.500 0.256 0.161 0.128 L (nm) 65 65 65 65 W (µm) 681 349 219 174 0.953 0.488 0.307 0.244 L (nm) 45 45 45 45 W (µm) 939 481 303 241 1.974 1.012 0.637 0.507 (S) 45 60 180 (S) 65 40 180 (S) 90 20 L (nm) (S) 130 Cutoff frequency ( GHz) (S) 4- PERFORMANCE SIMULATION RESULTS 4.1- Introduction This section presents simulation results characterizing the gain, NF and BW of the proposed distributed amplifier for 40 and 100 Gb/s operation. The results are compared with the performance of five DA architectures, namely I. Conventional DA which uses common-source amplification cells. II. Cascode DA which uses cascode configuration for the amplification. III. m-derived DA which is a conventional DA supported with both input and output m-derived stages. IV. Matrix DA where the amplification cells are arranged in matrix-form topology. V. Shifted second tier (SST) DA. All the DAs considered here are designed with four amplification cells per stage. The proposed DA, matrix and SST distributed amplifiers have two stages. Simulation results related to DA characteristic are obtained using AWR Microwave Office (version 10). The results are then used to design the proposed DA for 40 and 100 Gb/s optical receivers. 4.2- Gain and Noise Figure Spectra The aim of this section is to investigate the gain and NF spectra when the proposed DA is designed using different nano scale CMOS technologies. The results are to be compared with other DA architectures to assess the main features behind the proposed DA. Figs. 11 a-e illustrates the variation of the DA gains with frequency when the amplifiers are designed with 35 GHz cutoff frequency. This value of cutoff frequency is found to be suitable for operation around 40 Gb/s. Parts a-e of this figure are related to 180, 130, 90, 65 and 45 nm standards, respectively. Investigating these figures highlights the following finding. The proposed DA offers the highest gain with almost flat characteristic in the passband region compared with other DAs. Tables 4 and 5 list, respectively, the DC gain and BW of various DAs under investigation and taking the CMOS standard as independent parameter. 5672 | P a g e Februarury 28, 2015 ISSN 2277-3061 130 nm 180 nm (a) (b) 65 nm 90 nm (c) (d) 45 nm (e) Figure 11: Gain spectra of various DA configurations designed with 35 GHz cutoff frequency using (a) 180 nm standard, (b) 130 nm standard, (c) 90 nm standard, (d) 65 nm standard, (e) 45 nm standard. 5673 | P a g e Februarury 28, 2015 ISSN 2277-3061 Table 4: DC gain of various DAs designed with 35 GHz cutoff frequency. DC Gain (dB) Distributed Amplifier 180 nm 130 nm 90 nm 65 nm 45 nm Conventional 13 dB 19 dB 17 dB 20 dB 20 dB Cascode 9 dB 15 dB 23 dB 23 dB 24 dB m-derived 12 dB 19 dB 17 dB 19 dB 20 dB Matrix 22 dB 27 dB 29 dB 29 dB 35 dB Shifted second tier 21 dB 29 dB 33 dB 33 dB 39 dB This work 24 dB 42 dB 47 dB 56 dB 62 dB Table 5: Bandwidth of various DAs designed with 35 GHz cutoff frequency. Bandwidth ( GHz) Distributed Amplifier 180 nm 130 nm 90 nm 65 nm 45 nm Conventional 1.2 GHz 3 GHz 6 GHz 5 GHz 6 GHz Cascode 30 GHz 32 GHz 26 GHz 28 GHz 29 GHz m-derived 7 GHz 8 GHz 11 GHz 10 GHz 19 GHz Matrix 3.7 GHz 4 GHz 5 GHz 5.5 GHz 7 GHz Shifted second tier 9.7 GHz 20 GHz 13 GHz 16 GHz 18 GHz This work 31 GHz 31 GHz 34 GHz 32 GHz 34 GHz From the results illustrated in Fig. 11 and Tables 4 and 5 one can find out that the proposed DA the best results (highest gain and BW) when compared with other DAs. Conventional DA gives medium gain but not flat with low BW. Cascode DA gives low gain with BW range close to this work. M-derived DA gives flat medium gain with low BW. Matrix DA gives high gain but not flat with low BW. SST gives flat high gain with low BW. The simulation is repeated to investigate the characteristics of 80 GHz-cut off frequency DAs suitable for around 100 Gb/s operation. The results are presented in Fig. 12 to highlight the gain spectrum and summarised in Tables 6 and 7 to assess the DC gain and BW, respectively, of various DAs synthesized with nanoscale CMOS standards. 130 nm 180 nm (a) (b) Figure12: Gain spectra of various DA configurations designed with 80 GHz cut off frequency using (a) 180 nm standard, (b) 130 nm standard, (c) 90 nm standard, (d) 65 nm standard, (e) 45 nm standard. 5674 | P a g e Februarury 28, 2015 ISSN 2277-3061 90 nm 65 nm (c) (d) 45 nm (e) Figure12: (Continued) Table 6: DC gain of various DAs designed with 80 GHz cutoff frequency. DC Gain (dB) Distributed Amplifier 180 nm 130 nm 90 nm 65 nm 45 nm Conventional 3 dB 9 dB 9 dB 9 dB 11 dB Cascode 2 dB 8 dB 12 dB 15 dB 17 dB m-derived 3 dB 8 dB 8 dB 10 dB 12 dB Matrix 6 dB 15 dB 15 dB 15 dB 19 dB Shifted second tier 9 dB 12 dB 14 dB 15 dB 20 dB This work 10 dB 23 dB 34 dB 42 dB 49 dB 5675 | P a g e Februarury 28, 2015 ISSN 2277-3061 Table 7: Bandwidth of various DAs designed with 80 GHz cutoff frequency. Bandwidth ( GHz) Distributed Amplifier 180 nm 130 nm 90 nm 65 nm 45 nm Conventional 19 GHz 20 GHz 16 GHz 17 GHz 12 GHz Cascode 50 GHz 52 GHz 59 GHz 63 GHz 68 GHz m-derived 27 GHz 28 GHz 25 GHz 29 GHz 35 GHz Matrix 10 GHz 10 GHz 9 GHz 9 GHz 13 GHz Shifted second tier 27 GHz 31 GHz 32 GHz 30 GHz 58 GHz This work 70 GHz 75 GHz 74 GHz 71 GHz 75 GHz Investigating the results in Fig 12 and Tables 6 and 7 reveals that the same conclusions drawn from the 35 GHz cutoff frequency DAs are also applied. The results also show that when the cutoff frequency increases, the gain decreases for all DAs. However, the proposed DA gives the highest gain. One can apply these results to all standards (180, 130, 90, 65 and 45 nm). The simulation is carried further to assess the NF spectrum of 35 GHz – and 80 GHz cut off frequency DAs and the results are displayed in Figs. 13 and 4.4, respectively. Tables 8 and 9 summarises the dependants of low frequency NF on CMOS standard for various DA configurations. 180 nm (a) 130 nm (b) Figure13: Noise figure spectra of various DA configurations designed with 35 GHz cutoff frequency using (a) 180 nm standard, (b) 130 nm standard, (c) 90 nm standard, (d) 65 nm standard, (e) 45 nm standard. 5676 | P a g e Februarury 28, 2015 ISSN 2277-3061 90 nm (c) 65 nm (d) 45 nm (e) Figure13: (Continued) 5677 | P a g e Februarury 28, 2015 ISSN 2277-3061 180 nm 130 nm (a) (b) 90 nm 65 nm (c) (d) 45 nm (e) Figure14: Noise figure spectra of various DA configurations designed with 80 GHz cutoff frequency using (a) 180 nm standard, (b) 130 nm standard, (c) 90 nm standard, (d) 65 nm standard, (e) 45 nm standard. 5678 | P a g e Februarury 28, 2015 ISSN 2277-3061 Table 8: Noise figure of various DAs designed with 35 GHz cutoff frequency. DC Noise figure (dB) Distributed Amplifier 180 nm 130 nm 90 nm 65 nm 45 nm Conventional 3 dB 4 dB 16 dB 30 dB 3 dB Cascode 15 dB 25 dB 14 dB 10 dB 9 dB m-derived 5.1 dB 4.5 dB 8 dB 18 dB 1.7 dB Matrix 2.4 dB 2.2 dB 3.7 dB 2.2 dB 4 dB Shifted second tier 3 dB 3.6 dB 10 dB 5 dB 2 dB This work 4 dB 1.5 dB 5 dB 1.7 dB 2 dB Table 9: Noise figure of various DAs designed with 80 GHz cutoff frequency. DC Noise figure (dB) Distributed Amplifier 180 nm 130 nm 90 nm 65 nm 45 nm Conventional 18 dB 12 dB 26 dB 30 dB 36 dB Cascode 7 dB 7.3 dB 10.1 dB 8 dB 5 dB m-derived 18 dB 5 dB 0.8 dB 1 dB 0.3 dB Matrix 2.5 dB 2.5 dB 1.5 dB 4 dB 2 dB Shifted second tier 2 dB 3 dB 3 dB 4.5 dB 4 dB This work 6 dB 1.7 dB 3 dB 3.5 dB 3.5 dB From the results illustrated in Figs. 5 and 6 and Tables 8 and 9 one can find out that proposed DA gives low NF with almost flat spectrum when compared with other DAs. The value of the NF of this DA doesn‟t exceed 6 dB for all standards (180, 130, 90, 65 and 45 nm). 4.3- Effect of Transmission Line Cutoff Frequency The cutoff frequency of drain and gate transmission lines is usually used as one of the main entry design parameters for DAs. This section illustrates the depends of DA characteristic on the cutoff frequency. The results are reported for various DA architectures and various CMOS standards. The investigation is focused on low-frequency gain, low-frequency NF, and 3 dB BW. Figs. 15 a-e shows the dependence of the low-frequency gain on the line cutoff frequency for CMOS standards 180, 130, 90, 65 and 45 nm, respectively. Note that the proposed DA has the highest gain among the DAs considered here and this conclusion holds true for all cutoff frequency and CMOS standards. Note further that the amplifier gain decreases as the cutoff frequency increases. 5679 | P a g e Februarury 28, 2015 ISSN 2277-3061 180 nm 130 nm (a) (b) 90 nm 65 nm (c) (d) 45 nm (e) Figure15: Dependence ofgain on cutoff frequency for various DAs designed using CMOS technology of (a) 180 nm standard, (b) 130 nm standard, (c) 90 nm standard, (d) 65 nm standard and (e) 45 nm standard. Variation of low-frequency NF with cutoff frequency is given in Fig. 16. The results are reported for various DA configuration and CMOS standards. Investigation the results in this figure highlights the following findings. The proposed DA is characterized by relatively low NF over all values of cutoff frequency and CMOs standards. 5680 | P a g e Februarury 28, 2015 ISSN 2277-3061 180 nm 130 nm (a) (b) 65 nm 90 nm (c) (d) 45 nm (e) Figure16: Dependence ofnoise figure on cutoff frequency for various DAs designed using CMOS technology of (a) 180 nm standard, (b) 130 nm standard, (c) 90 nm standard, (d) 65 nm standard and (e) 45 nm standard. The calculation is carried further to estimate the 3 dB BW of the DAs and the results are displayed in Fig. 17 for various CMOS standards. The main conclusions drawn from this figure are I. For a given cutoff frequency, the proposed DA generally offers the highest BW compared with other DAs and this effect is more pronounced for high CMOS standards. For example, at 35 GHz cutoff frequency and 180 nm standard, the BWs of the proposed, cascode, SST, m-derived, matrix and conventional DAs are 31, 30, 9.7, 7, 3.7 and 1.2 GHz, respectively. These values are to be compared with 31, 31, 10, 8, 4 and 3 GHz for 130 nm DAs designed with 35 GHz cutoff frequency. II. In general, the BW of all DAs increases with cutoff frequency and this effect is more pronounced with the proposed DA. For example, if the DAs are designed with = 80 GHz and 180 nm standard, then the BW are 5681 | P a g e Februarury 28, 2015 ISSN 2277-3061 enhanced by 2.25, 1.66, 2.7, 3.85, 2.70 and 15.83 for the proposed, cascode, SST, m-derived, matrix and conventional DAs when compared with 35 GHz cutoff frequency counterparts. 130 nm 180 nm (a) (b) 90 nm 65 nm (c) (d) Figure17: Dependence ofbandwidth on cutoff frequency for various DAs designed using CMOS technology of (a) 180 nm standard, (b) 130 nm standard, (c) 90 nm standard, (d) 65 nm standard and (e) 45 nm standard. 45 nm (e) Figure17: (Continued) 5682 | P a g e Februarury 28, 2015 ISSN 2277-3061 4.4- Designing the Proposed DAs for 40 and 100 Gb/s Operation The results reported in the previous sections can be used as a guideline to design the proposed DA for front-end amplification in 40 Gb/s and 100 Gb/s optical receivers. The BW of the optical receiver is usually set equal to 0.7x bit rate as a hand of thumb estimate. From Fig. 17, one can deduced the cutoff frequencies for various CMOs standards that can be used as a design parameter to achieve BWs corresponding to 40 and 100 Gb/s. This design parameter is used to deduce both geometric and characteristics parameters of the DAs. Tables 10 and 11 list the obtained results, for both 40 and 100 Gb/s DAs, respectively. Again various CMOS standards are used to estimate the DA parameters for both operating bit rates. The thickness of the oxide layer is calculated from the gate capacitance using a simple model based on parallel-plate capacitance, = =3.9 (11.a) =3.45 x F/m (11.b) Figs. 18a and 18b show the gain and NF spectra for 40 Gb/s DAs designed with different CMOS standards. The calculations are repeated in Figs. 19a and 19b for the designed 100 Gb/s DAs. (a) (b) Figure 18: Gain and noise figure spectra for the proposed 40 Gb/s DA designed using different CMOS standards. (a) (b) Figure 19: Gain and noise figure spectra for the proposed 100 Gb/s DA designed using different CMOS standards. 5683 | P a g e Februarury 28, 2015 ISSN 2277-3061 Table 10: Design and characteristics parameters of the proposed DA for 40 Gb/s operation. Cutoff frequency of 35 GHz is used in the design. Value Parameter 180 nm 130 nm 90 nm 65 nm 45 nm Gate length (nm) 180 130 90 65 45 Gate width (µm) 158 233 306 399 551 Oxide thickness (nm) 4 3.8 3.7 3.4 3.1 Transconductance (S) 0.061 0.142 0.293 0.559 1.159 Gain (dB) 25 42 47 59 62 Noise figure (dB) 3 1.5 3.5 1.7 2 Gain - BandwidthProduct ( GHz) 551 3902 7611 28512 42772 Table 11: Design and characteristics parameters of the proposed DA for 100 Gb/s operation. Cutoff frequency of 80 GHz is used in the design. Value Parameter 180 nm 130 nm 90 nm 65 nm 45 nm Gate length (nm) 180 130 90 65 45 Gate width (µm) 69 101 134 174 241 Oxide thickness (nm) 4 3.8 3.7 3.4 3.1 Transconductance (S) 0.026 0.062 0.128 0.244 0.507 Gain (dB) 10 23 34 42 49 Noise figure (dB) 6 1.2 3 3.5 3.5 Gain x Bandwidth 221 1059 3708 8938 21137 Product ( GHz) From the results illustrated in graphs and tables above, one can find that the gain is increased by increasing the standard values, this can applied at both 35 and 80 GHz cutoff frequency, and the value of NF remains low. Gate width also increased by increasing the standard values, oxide thickens decrease by increasing the standard value, while transconductance increase by increasing standard value. 5- CONCLUSIONS A new distributed amplifier architecture has been introduced to achieve high flat gain and low noise figure over ultra wideband bandwidth. Investigation has been carried out to assess the performance of the proposed DA when it is implemented in various submicron CMOS standards process. The results have been used to design DAs for front-end amplification in 40 and 100 Gb/s optical receivers. The main conclusions drawn from this work are I. The proposed DA offers the highest gain among various DAs investigated in this work. II. The proposed DA offers a nearly flat gain over the wide bandwidth. The degree of gain flatness is the highest among the investigated DAs. III. Designing the DAs with high cutoff frequency leads to gain reduction. IV. The noise figure of the proposed DA does not exceed 6 dB for various CMOS standards. 6- REFERENCES [1] B. Razavil, „„Integrated circuit for optical communication‟‟, Second edition, Johenwiely and Sons Inc, 2012. [2] K. Kurokawa, „„Optical fiber for high power optical communication‟‟, Journal of Crystals, Vol. 2, No. 2, PP. 1382-1392, 2012. [3] V.S. Bagad, „„Optical fiber communication‟‟, First edition, MC. Grow. Hill, 2009. 5684 | P a g e Februarury 28, 2015 ISSN 2277-3061 [4] R. Zhou, M. Anandarujah, R. Maher, M. Paskov, D. Lavery, B.C. Thomsen, S. J. Savory and L.P. Barry, „„80 -km coherent DWDM-PON on 20-GHz grid with injected gain switched comb source”, IEEE Photonics Technology Letters, Vol. 26, No. 4, PP. 364-366, 2014. [5] G. Cossu, F. Bottoni, R. Corsini, M. Presi, and E. Ciaramella, „„40 Gb/s single R-SOA transmission by optical equalization and adaptive of DM‟‟, IEEE Photonics Technology Letters, Vol. 25, No. 21, PP. 2119 - 2122, 2013. [6] Q. Guo and V. Tran, „„Demonstration of a 40 Gb/s wave length reused WDM – PON using coding and equalization‟‟, IEEE Journal of Optical Communication and Networking, Vol. 5, No. 10, PP. 119 – 124, 2013. [7] J. Yu, and X. Zhou, „„Ultra–high–capacity DWDM transmission systems for 100 G and beyond‟‟, IEEE Communication Magazine, PP. 556 – 563, 2010. [8] J.C. Cartledge and A.S. karar, „„100 Gb/s intensity modulation and direct detection‟‟, Journal of Lightwave Technology, Vol. 32, No. 16, PP. 2809-2813, 2014. [9] N.A. Quadir, P.D. Townsend and P. Ossieur, „„An inductorless linear optical receiver for Gbaud/s (40Gb/s) PAM-4 modulation using 28nm CMOS‟‟, IEEE International Symposium on Circuits and Systems, Melbourne, PP. 2473-247, 2014. [10] J.M. Gene Bernaus, “Fiber-optic communication”, Departament de Teoria del Senyal i Comunicacions, UniversitatPolitecnica de Catalunya, 2010. (http://ocw.upc.edu/sites/default/files/materials/15011956/oc_chapter_i_100224-2804.pdf) [11] G. Wolf, S. Demichel, R. Leblanc, F. Bdache, R. Lefevre, G. Dambrine and H. Happy, “A metamorphic GaAS HEMT Distribut Amplifier with 50 GHZ bandwidth and low noise for 40 Gb/s optical receivers‟‟ , InstitutElectronique de Microelectronique de Nanotechnologie (IEMN), DepartementHyperfrequences et semiconductors, PP. 93-94, 2005. [12] J. C. Chien and L. –H. Lu, “40-Gb/s high-gain distributed amplifiers with cascaded gain stages in 0.18-µm CMOS”, IEEE Journal of Solid-State Circuits, Vol. 42, No. 12, PP. 2715-2724, 2007. [13] K. Moez and M. Elmusry, “A new loss compensation technique for CMOS distributed amplifiers‟‟, IEEE Transactions on Crcuits and Systems, Vol. 56, No. 3, PP. 185-188, 2009. [14] K. Entesari, A.R. Tavakoli and A. Helmy, “CMOS distributed amplifier with extended flat bandwidth and improved input matching using gate line with coupled inductors‟‟, IEEE Transactions on Microwave Theory and Techniques, Vol. 57, No. 12, PP. 2862 – 2870, 2009. [15] A. Ghadiri and K. Moez, “Gain-Enhanced distributed amplifier using negative capacitance‟‟, IEEE Transactions on Circuit and Systems, Vol. 57, No. 11, PP. 2834 – 2841, 2010. [16] C. K. Chien, H. H. Hsich, H. S. Chen and L. H. Lu, “A transimpedance amplifier with tunable bandwidth in 0.18 µm CMOS‟‟, IEEE Transactions on Microwave Theory and Techniques, Vol. 58, No. 3, PP. 498-504, 2010. [17] J. Kim and J. F. Buckwalter, „„A 92 GHz bandwidth distributed amplifier in 45nm SOI CMOS Technology‟‟, IEEE Microwave and Wireless Components Letters, Vol. 21, No. 6, PP. 329 – 331, 2011. [18] A. Jahanian and P. Heydari, „„A CMOS distributed amplifier with distributed active input balun using GBW and linearity enhancing techniques‟‟, IEEE Transactions on Microwave Theory and Techniques, Vol. 60, No. 5, PP. 1331 – 1340, 2012. [19] C. Feng, W. M. Lim and K. S. Yeo, „„A compact 2.1 – 39 GHz self – biased low – niose amplifier in 65nm CMOS technology‟‟, IEEE Microwave and Wireless Components Letters, Vol. 23, No. 12, PP. 662 – 669, 2013. [20] J. C. Kao, P. C. Huang and H. W. fellow, „„A novel distributed amplifier with high gain, Low noise, and high output power in 0.18 m CMOS technology‟‟, IEEE Transactions on Microwave Theory and Techniques, Vol. 61, No. 4, PP. 1533 – 1541, 2013. [21] M. K. Cho, J. G. Kim and D. Baek, “A switch less CMOS Bi- Directional distributed gain amplifier with multi – octave bandwidth‟‟ , IEEE Microwave and Wireless Component Letters, Vol. 23, No. 11, PP. 611 – 613, 2013. [22] K. Kim and C. N. Fellow, “A concurrent Ku / K / Ka Tri-band distributed power amplifier with negative – resistance active notch using SiGeBiCMOS process” , IEEE Transactions on Microwave Theory and Techniques, Vol. 62, No. 1, PP. 125-135, 2014. [23] J. Kim, J.F.Buckwalter, “A 92 GHz bandwidth distributed amplifier in 45 nm SOI CMOS technology” ,IEEE Microwave and Wireless Component Letters, Vol.21, No.6,June 2011. [24] Y. Cao, “Predictive technology model for robust nanoelectronic design”, 1 2011. st Edition, Predictive Process Design Kids, th [25] S. Serdar and C. Smith, “Microelectronic circuits”, 6 Edition, Oxford University Press, 2010. 5685 | P a g e Februarury 28, 2015 ISSN 2277-3061 Author’s biography EsraaEhsan Al-Bayati was born in London, UK, in 1987. She received the B.Sc. degree in Electronic and Communications Engineering from Al-Nahrain University, Iraq in 2009. Currently, she is an M.Sc. student in the Electronic and Communications Engineering Department at Al-Nahrain University. Her research interests include Optical and wireless communications, Distributed microwave amplifiers and receivers, CMOS and Communication systems. Raad Sami Fyathwas born in Maysan, Iraq, in 1954. He received the B.Sc. degree in Electrical Engineering from the University of Basrah, Iraq, in 1976, the M.Sc. degree in Electronics and Communications Engineering from the University of Baghdad, Iraq, in 1987, and the PhD degree in Electronics Engineering from University of Wales-Bangor, UK, in 1990. Currently, he is a professor of electronics and communications engineering at the College of Engineering, Al-Nahrain University, Baghdad, Iraq. His research interests include Optical and wireless communications, Optoelectronics, and Nanophotonics. He published more than 100 papers in different scientific journals and conference proceedings. 5686 | P a g e Februarury 28, 2015
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Biophosphorescence in fluorescent millipedes (Diplopoda: Xystodesmidae) and its relationships with bioluminescence OPEN Vadim R. Viviani Three types of luminescence have been reported in living organisms: bioluminescence (BL), ultraweak chemiluminescence and biofluorescence (FL). In millipedes, both BL and FL have been reported in Motyxia sequoiae and related Xystodesmidae species. Noteworthy, when walking at night with a UV lantern at the Biological Station of Highlands, I found three blue-fluorescent millipedes (Deltotaria brimleii, Deltotoria sp and Euryus orestes) that also displayed phosphorescence after turning off the UV source. The phosphorescence of the cuticle was in the green region (λmax = 525 nm). The phosphorescence remained associated with cuticle and pellets, but frozen fluorescent supernatants, also displayed phosphorescence. The fluorescent compounds extracted from the cuticles in water and methanol and separated by TLC, displayed fluorescence spectra similar to that of 6-pteridine carboxylic acid. In contrast to Motyxia sequoiae cuticle extracts, no bioluminescence was found in Deltatoria and Euryus extracts  in the presence of MgATP, but weak green chemiluminescence was detected with ­H2O2 and superoxide. The spectral overlapping of phosphorescence of these millipedes with the bioluminescence of Motyxia (~ 507 nm) and the intimate association of both types of luminescence with the cuticles, raises the possibility that bioluminescence in Motyxia may arise from chemiluminescence reactions preferentially generating triplet excited states instead of singlet states. In living organisms, three types of luminescence have been reported: (1) bioluminescence, a special case of enzymatically catalyzed chemiluminescence for communicative ­purposes1, (2) ultraweak chemiluminescence resulting from side-reactions of the oxidative ­metabolism2 and (3) fluorescence, also referred as biofluorescence, a kind of photoluminescence which depends on excitation by light. Biofluorescence, has been reported for several classes of organisms, including mainly marine organisms with fluorescent proteins (FPs), arthropods, amphib- ians, reptiles, birds and even ­mammals3–6. In marine organisms such as jellyfishes, GFPs participate in modula- tion of bioluminescence spectrum through energy transfer (BRET)7, and possibly as fluorescent light dissipators of damaging UV light in some corals. In some cases, such in the case of bird´s plumage, in which fluorescence enhances the plumage color effect for sexual attraction ­purposes8,9, the biological function of fluorescence is evident. In some insects and amphibians, fluorescence may also display an amplification effect on visual clues. In other cases, such as the scorpion´s cuticle, fluorescence does not have any apparent function, being just a side effect of production of cuticle fluorescent ­compounds10. fl Bioluminescence occurs in several organisms, both marine and terrestrial. www.nature.com/scientificreports www.nature.com/scientificreports www.nature.com/scientificreports Department of Physics, Chemistry and Mathematics, Center for Sustainable Sciences and Technologies (CCTS), UFSCar, Sorocaba, SP, Brazil. email: viviani@ufscar.br Results and discussion Field observations of millipede fluorescence and phosphorescence Field observations of millipede fluorescence and phosphorescence pl p p When walking at night in the late April and beginning of May spring at HBS, 3 strongly fluorescent millipedes were readily observed upon turning an UV LED lantern. These species were identified as Deltotaria bremleii, Deltotaria sp and Euryus orestes (Fig. 1). During the day, these millipedes were found in the woods hidden under the litter and near and under decayed logs in the forest. At night they were easily found by their strong bluish fluorescence upon turning on a LED UV lantern. Upon touching them, they release from lateral glands a defensive cyanide secretion with characteristic almond fragrance. In Deltoria sp, only the legs and antennae fluoresced, whereas in D. bremleii and Euryurus orestes the dorsal cuticle exhibited strong fluorescence. The fluorescence of wandering millipedes at night could also be filmed with a cell phone video camera (Video-1). Noteworthy, I observed that after turning off the UV lantern, the millipedes still phosphoresced for less than 1 s. www.nature.com/scientificreports/ Besides bioluminescent species, the Xystodesmidae family also includes a diversity of colorful millipedes which release hydrogen cyanide and benzaldeyde from lateral glands for defensive purposes, being especially repre- sented in Eastern United ­States16,17.i Noteworthy, bioluminescence in Motyxia spp is cuticular, does not involve a defined light organ, and involves a still poorly investigated photoprotein system which is dependent on ATP and ­Ca2+ or ­Mg2+11,18,19. The photo- protein, which was partially isolated by Shimomura, has ~ 100 kDa and it may involve a porphyrin chromophore being very unstable in ­solution11,19. Furthermore, besides the cuticular bioluminescence, Motyxia also displays strong cuticular blue-green fluorescence under UV light, but it is not clear whether there is or not a relationship between bioluminescence and fluorescence in these millipedes. Similar fluorescence has also been reported in the non-bioluminescent xystodesmid train millipede, Parafrontaria laminate, from ­Japan20. The fluorescent compounds isolated from the cuticles of Motyxia sequoiae and Parafrontaria millipedes were identified as pterin- 6´carboxylic and 7,8-dihydropterin carboxylic ­acids20,21. The authors suggested that these compounds could be the putative emitters of Motyxia bioluminescence based on the fluorescence, and also on chemiluminescent properties in the presence of hydrogen peroxide, but no conclusive experiment has been shown yet regarding chemiluminescence of such compounds. Furthermore, the spectral properties of the bioluminescence (green) and of the fluorescence (blue-green) in Motyxia do not match, which would be expected if these compounds functioned as the bioluminescence emitters. Thus, whether there is a relationship between the blue fluorescence these pteridin carboxylic acids and the greenish bioluminescence in millipedes remains unclear. p y g p Very recently, when walking in the woods at night at the Biological Station of Highlands (HBS) in North- Carolina with a LED UV lantern, I found 3 species of Xystodesmidae millipedes that are strongly fluorescent, emitting a blue-green fluorescence (Fig. 1). To my surprise, after turning off the UV light source, these millipedes also displayed a rapidly vanishing phosphorescence (Fig. 1). In this note, I report the first characterization of this phosphorescence and also of the fluorescence of these millipedes, and compare these photophysical properties with the bioluminescence properties of the xystodesmid millipede relative, Motyxia sequoiae, kindly provided by J.W ­Hastings† in 2005. To our knowledge, this is the first report of occurrence of phosphorescence in animals. Anatomical location of fluorescence and phosphorescencel l p p Back in the lab, I could photograph the fluorescence (Fig. 1) and phosphorescence. The fluorescence is bluish and arises from both the dorsal and ventral cuticles of the body in these millipedes. However, in the black-reddish specimens of Deltoria bremleii the blue fluorescence was more intense in the reddish/yellowish parts of the dorsal segments (Fig. 1A, B), and less intense in the dark parts. In of Deltotoria sp, only the legs and antennae displayed intense fluorescence (Fig. 1D, E). In Euryurus orestes the fluorescence was intense in most of the dorsal cuticle, and weaker in the reddish marks (Fig. 1G, H). The blue fluorescence could be more easily seen from the whitish areas, especially the legs and ventral tegument (Fig. 1F).h y g g g The phosphorescence of these millipedes was usually more intense in the whitish intersegmental and ventral areas, and in the legs. In Deltatoria bremleii, the more intense phosphorescence was usually detected in the intersegmental parts and legs, whereas in Euryurus orestes it was detected over all ventral area and almost all the dorsal part of the segments, with the exception of the reddish spots (Fig. 1I). Therefore, there was a good match between the anatomical location of fluorescence and phosphorescence in the dorsal part of the segments as well as the legs (Fig. 1H and I), an indication that the compounds responsible for fluorescence and phosphorescence could be the same. Fluorescence and phosphorescence spectrah The phosphorescence decay is very fast: it visually decays completely in less than 1 s. By using a spectrofluorom- eter and also a very sensitive CCD based spectroluminometer, we were able to scan the emission spectrum of the rapidly vanishing phosphorescence of the cuticle after UV light irradiation. The emission was in the green region, with a peak at 525–530 nm (Fig. 2; Table 1). Therefore, the emission spectrum of this luminescence after turning off the UV light source was red-shifted in relation to the fluorescence spectrum, indicating that this luminescence is indeed phosphorescence. Delayed fluorescence is unlikely considering the red-shifted spectrum in relation to fluorescence. Biophosphorescence in fluorescent millipedes (Diplopoda: Xystodesmidae) and its relationships with bioluminescence OPEN It arises from exothermic oxidative reactions in which compounds generally called luciferins are oxidized by molecular oxygen in the presence of enzymes called luciferases or photoproteins, producing peroxidic intermediates, whose spontaneous cleavage preferentially yield singlet (fluorescent state) excited products that decay, emitting ­light1. Among arthropods, it occurs in marine crustaceans, millipedes and mainly ­insects11. Despite some confusion in the old literature regarding the use of the term phosphorescence for biolumines- cence, until recently phosphorescence was not known to occur among living organisms or biological materials. Recently, phosphorescence has been reported in rice, starch and frozen serum albumin ­solutions12. An image of phosphorescence has been published in millipedes of Xystodermidae family, but no detailed characterization of this phosphorescence has been carried out ­yet13. p p y In millipedes, bioluminescence was originally reported in Motyxia sequoiae from the Xystodesmidae family, which occurs in ­California14. More recently, weak bioluminescence was also reported in other Motyxia ­species15. Scientific Reports | (2023) 13:22171 | https://doi.org/10.1038/s41598-023-47860-9 www.nature.com/scientificreports/ Fluorescence and phosphorescence properties of extracted material Upon extraction of Deltatoria bremleii and Euryus orestes cuticles and centrifugation, intense bluish fluorescence was recovered in both aqueous and acidic methanol supernatants (Fig. 3). The fluorescence spectra of aqueous extracts had excitation peaks at 251 and 364 nm, and emission at 468 nm (Fig. 4; Table 1). In methanol, although the extracted pigments displayed similar excitation spectra of the aqueous extracts, the emission spectrum was https://doi.org/10.1038/s41598-023-47860-9 Scientific Reports | (2023) 13:22171 | www.nature.com/scientificreports/ /scientificreports/ slightly blue-shifted peaking at 450 nm. The fluorescent pigments were highly soluble in water and Figure 1. Highlands Biological station (HBS) millipedes: (A) Deltatoria bremleii; (B) Deltatoria brem displaying dorsal fluorescence upon UV irradiation; (C) Deltatoria bremleii lateral body phosphoresc Deltatoria sp fluorescence; (E) Deltatoria sp showing only legs fluorescence; (F) Euryurus orestes; (G) orestes displaying blue fluorescence; (H) Euryurus orestes dorsal blue fluorescence; (I) Euryurus oreste phosphorescence. al station (HBS) millipedes: (A) Deltatoria bremleii; (B) Deltatoria bremleii upon UV irradiation; (C) Deltatoria bremleii lateral body phosphorescence; (D) Deltatoria sp showing only legs fluorescence; (F) Euryurus orestes; (G) Euryurus ence; (H) Euryurus orestes dorsal blue fluorescence; (I) Euryurus orestes dorsal Figure 1. Highlands Biological station (HBS) millipedes: (A) Deltatoria bremleii; (B) Deltatoria bremleii displaying dorsal fluorescence upon UV irradiation; (C) Deltatoria bremleii lateral body phosphorescence; Deltatoria sp fluorescence; (E) Deltatoria sp showing only legs fluorescence; (F) Euryurus orestes; (G) Euryu orestes displaying blue fluorescence; (H) Euryurus orestes dorsal blue fluorescence; (I) Euryurus orestes dors phosphorescence. Figure 1. Highlands Biological station (HBS) millipedes: (A) Deltatoria bremleii; (B) Deltatoria bremleii displaying dorsal fluorescence upon UV irradiation; (C) Deltatoria bremleii lateral body phosphorescence; (D) Deltatoria sp fluorescence; (E) Deltatoria sp showing only legs fluorescence; (F) Euryurus orestes; (G) Euryurus orestes displaying blue fluorescence; (H) Euryurus orestes dorsal blue fluorescence; (I) Euryurus orestes dorsal phosphorescence. Figure 1. Highlands Biological station (HBS) millipedes: (A) Deltatoria bremleii; (B) Deltatoria bremleii displaying dorsal fluorescence upon UV irradiation; (C) Deltatoria bremleii lateral body phosphorescence; (D) Deltatoria sp fluorescence; (E) Deltatoria sp showing only legs fluorescence; (F) Euryurus orestes; (G) Euryurus orestes displaying blue fluorescence; (H) Euryurus orestes dorsal blue fluorescence; (I) Euryurus orestes dorsal phosphorescence. Figure 1. Fluorescence and phosphorescence properties of extracted material Highlands Biological station (HBS) millipedes: (A) Deltatoria bremleii; (B) Deltatoria bremleii displaying dorsal fluorescence upon UV irradiation; (C) Deltatoria bremleii lateral body phosphorescence; (D) Deltatoria sp fluorescence; (E) Deltatoria sp showing only legs fluorescence; (F) Euryurus orestes; (G) Euryurus orestes displaying blue fluorescence; (H) Euryurus orestes dorsal blue fluorescence; (I) Euryurus orestes dorsal phosphorescence. slightly blue-shifted peaking at 450 nm. The fluorescent pigments were highly soluble in water and methanol, but could not be efficiently acid extracted in ethyl acetate, indicating that such compounds are highly polar. The residue obtained upon solvent evaporation of methanol extracts was whitish for the ventral cuticle and reddish for the dorsal cuticle, and in both cases displayed strong blue fluorescence. https://doi.org/10.1038/s41598-023-47860-9 Scientific Reports | (2023) 13:22171 | www.nature.com/scientificreports/ Figure 2. Phosphorescence spectrum of Deltatoria bremleii ventral cuticle and pellet of extracted material. The phosphorescence was obtained by short irradiation with UV LED lantern (370 nm), and shortly after luminescence spectra scanning. Figure 2. Phosphorescence spectrum of Deltatoria bremleii ventral cuticle and pellet of extracted material. The phosphorescence was obtained by short irradiation with UV LED lantern (370 nm), and shortly after luminescence spectra scanning. Luminescence/λmax (nm) Motyxia sequoiae* Deltatoria bremleii Euryus orestes Phosphorescence (λPh ) Cuticle – 525 520 Pellet – 525 525 Frozen supernatant 498 – 507 Fluorescence λEX – 251/364 251/364 λFL ­(H2O) 467 453 (467) 459 λFL (metanol) 454 447 450 Chemiluminescence (λCL )† – 513 – Bioluminescence (λBL )‡ 507 – – Luminescence/λmax (nm) Motyxia sequoiae* Deltatoria bremleii Euryus orestes Phosphorescence (λPh ) Cuticle – 525 520 Pellet – 525 525 Frozen supernatant 498 – 507 Fluorescence λEX – 251/364 251/364 λFL ­(H2O) 467 453 (467) 459 λFL (metanol) 454 447 450 Chemiluminescence (λCL )† – 513 – Bioluminescence (λBL )‡ 507 – – Table 1. Comparative photoluminescence and chemi- and bioluminescence spectral properties of millipedes. *We did not test Motyxia cuticle for phosphorescence. † Chemiluminescence of concentrated methanol extracts in DMSO with potassium superoxide. ‡ Bioluminescence of crude extracts in the presence of ­MgSO4 and ATP. Table 1. Comparative photoluminescence and chemi- and bioluminescence spectral properties of millipedes. *We did not test Motyxia cuticle for phosphorescence. † Chemiluminescence of concentrated methanol extracts in DMSO with potassium superoxide. ‡ Bioluminescence of crude extracts in the presence of ­MgSO4 and ATP. Table 1. Comparative photoluminescence and chemi- and bioluminescence spectral properties of millipedes. *We did not test Motyxia cuticle for phosphorescence. Fluorescence and phosphorescence properties of extracted material † Chemiluminescence of concentrated methanol extracts in DMSO with potassium superoxide. ‡ Bioluminescence of crude extracts in the presence of ­MgSO4 and ATP. Table 1. Comparative photoluminescence and chemi- and bioluminescence spectral properties of millipedes. *We did not test Motyxia cuticle for phosphorescence. † Chemiluminescence of concentrated methanol extracts in DMSO with potassium superoxide. ‡ Bioluminescence of crude extracts in the presence of ­MgSO4 and ATP. Figure 3. Phosphorescence and fluorescence of Deltatoria bremleii extracted material upon UV light irradiation: (A) fluorescence; (B) phosphorescence of pelleted material and debris after UV light irradiation; (C) phosphorescence of frozen supernatant. Figure 3. Phosphorescence and fluorescence of Deltatoria bremleii extracted material upon UV light irradiation: (A) fluorescence; (B) phosphorescence of pelleted material and debris after UV light irradiation; (C) phosphorescence of frozen supernatant. Scientific Reports | (2023) 13:22171 | https://doi.org/10.1038/s41598-023-47860-9 www.nature.com/scientificreports/ p Figure 4. Fluorescence spectra of Deltatoria bremleii millipedes cuticle extracts: (A) excitation spectrum; (B) fluorescence spectra excited at 364 nm: (a) methanol extract of ventral cuticle; (b) methanol extract of dorsal cuticle; (c) aqueous extract of dorsal cuticle; (d) aqueous extract of ventral cuticle. Figure 4. Fluorescence spectra of Deltatoria bremleii millipedes cuticle extracts: (A) excitation spectrum; (B) fluorescence spectra excited at 364 nm: (a) methanol extract of ventral cuticle; (b) methanol extract of dorsal cuticle; (c) aqueous extract of dorsal cuticle; (d) aqueous extract of ventral cuticle. On the other hand, phosphorescence always remained in the pelleted material and decanted debris (Fig. 3). As expected, both aqueous and methanol extracts did not display any visually observable phosphorescence, even when oxygen was removed by slight vacuum made inside a blood collecting type vessel, using a hypoder- mic syringe. However, the fluorescent aqueous extracts of these millipedes, once frozen in dry ice, displayed intense phosphorescence in the green region (Table 1). Under such conditions we could also measure the life time of phosphorescence of frozen extracts, which averaged ~75 ms. Once again, these results confirm that the delayed light emission is true phosphorescence and not delayed fluorescence and the possibility that the pigment responsible for the fluorescence and phosphorescence could be the same compound, however phosphorescence is displayed only in the solid state of the cuticle or frozen crystals. Pigment partial isolation and propertiesh g The methanol extracts and aqueous extracts were submitted to TLC to separate the compounds in the fluorescent spots. Under Ethyl acetate/ethanol/H2O as mobile phase, the Deltatoria bremleii dorsal cuticle extracts displayed at least 4 fluorescent spots, two with higher migration coefficients displaying blue fluorescence, and two almost merging bands with lower Rf displaying blue-green fluorescence spectra upon excitation at 364 nm (Fig. 5). The ventral cuticle displayed mainly a pigment with blue-green fluorescence with lower Rf. On the other hand, when using 60% methanol as a mobile phase, the TLC of both ventral and dorsal cuticle extracts displayed a main blue fluorescent spot with very high Rf, and a smear with the same Rf of commercial 6-pteridinic acid (Table 2). It is also noteworthy that a considerable amount of the blue fluorescent material was retained at the origin of TLC. Previously, Kuse et al. isolated from the bioluminescent millipede Motyxia sequoiae20 and from the Japanese fluorescent train millipede Parafrontaria laminate21 two main fluorescent compounds with similar fluorescence spectral properties and structures, 7,8-dihydropterin-6-carboxylic acid and pterin-6-carboxylic acid. The fluorescence properties of the eluted compounds from the blue fluorescent spots from Deltatoria bremleii and Euryus orestes millipedes, are similar to those of 7,8-dihydropterin-6-carboxylic acid and pterin-6-carboxylic acid, suggesting that these compounds could be similar to pteridine compounds. Comparison of photoluminescence and bioluminescence in millipedes extracts §Peak of fluorescence spectra of water eluted compounds. Table 2. Migration (Rf) and Fluorescence properties of TLC partially isolated compounds from millipede cuticles. *Solvent system I: Methanol 60%. **Solvent system II: Ethyl acetate/Ethanol/H2O (5:3:2). §Peak of fluorescence spectra of water eluted compounds. were phosphorescent too. However, similarly to Deltatoria and Euryus aqueous extracts, stored frozen Motyxia sequoiae cuticle aqueous extracts were also phosphorescent upon UV light irradiation. As expected, the crude extracts of Motyxia sequoiae cuticle produced weak greenish bioluminescence in the presence of ATP and mag- nesium or calcium ions (Table 1). The peak of the in vitro bioluminescence spectrum of Motyxia sequoiae was 507 nm (Fig. 6), just in the green region. No light emission, however, could be luminometrically detected using non-bioluminescent Deltatoria and Euryus millipedes cuticle extracts under the same conditions, indicating that these millipedes do not have an active photoprotein. Furthermore, the cross-reaction between Motyxia sequoiae photoprotein active cold extracts and Deltotaria cuticle hot extracts were negative for the biolumines- cence reaction. Comparison of photoluminescence and bioluminescence in millipedes extracts The fluorescence and bioluminescence of Motyxia have been already ­studied11. The thawed millipedes pro- duced weak bioluminescence and also displayed fluorescence when irradiated with UV. Unfortunately, at the time we investigated the phosphorescence of the millipedes Deltotaria and Euryus, we had already run out of Motyxia sequoiae millipedes, which hampered the possibility to further investigate whether their cuticles https://doi.org/10.1038/s41598-023-47860-9 Scientific Reports | (2023) 13:22171 | www.nature.com/scientificreports/ www.nature.com/scientificreports/ Figure 5. TLC of fluorescent pigments on silica-gel plates after UV light irradiation: (A) Ethyl acetate/Ethanol/ H2O (5:2:3); (B) Methanol 60%. (1) 6´-pteridinic carboxylic acid; (2) methanol/TFA extract of Deltatoria ventral cuticle; (3) methanol/TFA extract of Deltatoria bremleii dorsal cuticle; (4) aqueous extract of Deltatoria bremleii ventral cuticle; (5) aqueous extract of Deltatoria bremleii dorsal cuticle; (6) aqueous extract of Euryus orestes cuticle. Figure 5. TLC of fluorescent pigments on silica-gel plates after UV light irradiation: (A) Ethyl acetate/Ethanol/ H2O (5:2:3); (B) Methanol 60%. (1) 6´-pteridinic carboxylic acid; (2) methanol/TFA extract of Deltatoria ventral cuticle; (3) methanol/TFA extract of Deltatoria bremleii dorsal cuticle; (4) aqueous extract of Deltatoria bremleii ventral cuticle; (5) aqueous extract of Deltatoria bremleii dorsal cuticle; (6) aqueous extract of Euryus orestes cuticle. Table 2. Migration (Rf) and Fluorescence properties of TLC partially isolated compounds from millipede cuticles. *Solvent system I: Methanol 60%. **Solvent system II: Ethyl acetate/Ethanol/H2O (5:3:2). §Peak of fluorescence spectra of water eluted compounds. Solvent System/Fluorescent spots Deltatoria bremleii Euryus orestes Motyxia sequoiae Rf λFL (nm)§ Rf Rf λFL (nm)§ Solvent I*  Spot 1 0.69 449 0.69 0.72 443  Spot 2 0.57 456 0.57 Solvent II**  Spot 3 0.57 449 0.57 – –  Spot 2 0.52 456 0.52 – –  Spot 1 0.42 465 0.42 – – Table 2. Migration (Rf) and Fluorescence properties of TLC partially isolated compounds from millipede cuticles. *Solvent system I: Methanol 60%. **Solvent system II: Ethyl acetate/Ethanol/H2O (5:3:2). §Peak of fluorescence spectra of water eluted compounds. Solvent System/Fluorescent spots Deltatoria bremleii Euryus orestes Motyxia sequoiae Rf λFL (nm)§ Rf Rf λFL (nm)§ Solvent I*  Spot 1 0.69 449 0.69 0.72 443  Spot 2 0.57 456 0.57 Solvent II**  Spot 3 0.57 449 0.57 – –  Spot 2 0.52 456 0.52 – –  Spot 1 0.42 465 0.42 – – Table 2. Migration (Rf) and Fluorescence properties of TLC partially isolated compounds from millipede cuticles. *Solvent system I: Methanol 60%. **Solvent system II: Ethyl acetate/Ethanol/H2O (5:3:2). Chemiluminescence properties of millipedes cuticles Despite being non-bioluminescent, the Deltatoria bremleii and Euryus orestes millipedes cuticle extracts, simi- larly to the Japanese millipede Parafrontaria laminate21, produced a very weak chemiluminescence, just above the detection limit of the luminometer (Table 1), in the presence of 0.1–3% ­H2O2, indicating the presence of chemiluminescent compounds, similarly to the report of Kuse et al.21. The pelleted material also displayed chemi- luminescence upon addition of 0.1–1% ­H2O2 or potassium superoxide, which could be detected using a highly sensitive CCD camera (Fig. 7). The concentrated methanolic extracts, once dissolved in DMSO in the presence of potassium superoxide, produced weak chemiluminescence which was intense enough to allow the measure- ment of the emission spectrum using a sensitive spectroluminometer, displaying an emission peak at 507 nm. Although the chemiluminescence under such harsh circumstances could not be easily attributed to a specific reaction of the isolated pigments yet, the chemiluminescence spectrum (507 nm) considerably overlaps with the phosphorescence and bioluminescence spectra of these millipedes, suggesting that this chemiluminescence may arise from the oxidation of the same compounds responsible for phosphorescence and bioluminescence. Further studies are undergoing to better understand the origin of such chemiluminescence. Scientific Reports | (2023) 13:22171 | https://doi.org/10.1038/s41598-023-47860-9 www.nature.com/scientificreports/ www.nature.com/scientificreports/ Figure 6. In vitro bioluminescence spectrum of Motyxia sequoiae crude extracts. Figure 6. In vitro bioluminescence spectrum of Motyxia sequoiae crude ext Figure 6. In vitro bioluminescence spectrum of Motyxia sequoiae crude extracts. Figure 7. Chemiluminescence of Deltatoria bremleii millipedes cuticles precipitated debris: (A) upon addition of ­H2O2 and (B) upon addition of potassium superoxide. Figure 7. Chemiluminescence of Deltatoria bremleii millipedes cuticles precipitated debris: (A) upon addition of ­H2O2 and (B) upon addition of potassium superoxide. www.nature.com/scientificreports/ of the relatively close relatives Motyxia spp of the Xystodesmidae family. It is noteworthy that the phosphores- cent spectra of Deltatoria and Euryus cuticles, as well as Motyxia sequoiae frozen extracts, in the green region, considerably overlap with the bioluminescent spectrum of Motyxia sequoiae. of the relatively close relatives Motyxia spp of the Xystodesmidae family. It is noteworthy that the phosphores- cent spectra of Deltatoria and Euryus cuticles, as well as Motyxia sequoiae frozen extracts, in the green region, considerably overlap with the bioluminescent spectrum of Motyxia sequoiae. y p p y q It is generally considered that all known bioluminescence examples arise from chemiluminescent reactions that yield mainly excited singlet species (fluorescent state). This is valid and expected for liquid state solvent environments, such as the cytoplasm of many photocytes where most luciferin-luciferase enzymatic reactions occur, in which the lifetime of the excited state shall be extremely short to be emissive. On the other hand, triplet excited species, with the exception of ultraweak ­chemiluminescence2,22, have not been usually considered reason- able candidates for the highly efficient bioluminescent reactions, because of their long life-times that makes them easily quenched by oxygen and other molecules in solution rather than decaying emitting light. Similarly to the Deltatoria and Euryues phosphorescence, Motyxia sequoiae bioluminescence is also strictly associated with the cuticle which is an almost solid-state tissue, and not with soft tissues. In such case, triplet spe- cies may have a chance to be emissive, giving off phosphorescence instead of being quenched, as we have shown for the first time in the cuticles of the non-bioluminescent related species Deltatoria spp and Euryus orestes from the same subfamily. It is likely that Motyxia sequoiae cuticle is also phosphorescent, as indicated by their frozen extracts, although this property may have been overlooked in live millipedes.h g p p y y p Therefore, here I raise the possibility that, in the case of millipedes of the Xystodesmidae family, biolumi- nescence could be associated with the generation of triplet excited species and that the emissive process of such chemiluminescence could be phosphorescence instead of fluorescence. Alternatives could be delayed fluorescence or sensitized triplet-singlet luminescence. Concluding remarksi Here I report for the first time the occurrence of phosphorescence in the cuticles of fluorescent millipedes, Deltoria spp and Euryus orestes occurring in North Carolina forests, being also the first report characterizing phosphorescence in arthropods and animals. The phosphorescence of these millipedes arises from the cuticle, has a short life time and its emission spectrum in the green region is red-shifted as compared with the spectrum of its fluorescence. This phosphorescence may arise from pteridine acid derivatives in the cuticle that may also be responsible for the fluorescence. Remarkably, the considerable overlapping of the phosphorescence spectrum of these millipedes cuticles and frozen extracts with the bioluminescence spectrum of the close relative Motyxia sequoiae and its extracts raises the possibility, for the first time, that bioluminescence in millipedes could be generated by a chemiluminescent reaction generating preferentially triplet excited states (phosphorescent state) instead of singlet states (fluorescent state). www.nature.com/scientificreports/ However, such possibilities are unlikely, considering the red-shifted spectrum of phosphorescence that argues against delayed fluorescence, and the closely matching of the biolumi- nescence spectrum of Motyxia with the phosphorescence spectrum of the related Deltatoria bremleii and Euryus orestes, that argues against an energy transfer process which requires a higher energy phosphorescence spectrum donor to sensitize the fluorescent emitter.h l The photoprotein responsible for the bioluminescence reaction in Motyxia sequoiae has been isolated in the active form in solution, but is very unstable, indicating that it is more likely an insoluble protein which could be incorporated in the cuticle during the sclerotization process. In arthropods, the process of sclerotization and hardening of cuticles involve oxidation by reactive pigment intermediates, such as quinones and pteridines, that may react with proteins, thereby generating excited species. Although the active photoprotein has been partially isolated in the soluble fraction, which in principle argues against the participation of emissive triplet excited states, the definition of photoprotein itself does not exclude such possibility. The photoprotein is a pro- tein that oxidizes the substrate, stabilizing a peroxide intermediate, which in the presence of triggering agents such as calcium, undergoes conformational changes promoting its breakdown and generating an excited prod- uct that decays emitting light just once, without apparent turnover like a typical ­luciferase1. Furthermore, the relatively efficient enzyme generation of triplet species chemiluminescence is not an unlikely possibility, it has been already demonstrated in vitro for the HRP/Isobutanal system which produces triplet acetone by Cilento and ­coworkers22. In such a circumstance, a triplet excited product generated inside a closed, relatively rigid and protective environment against solvent quenching of a protein associated to the cuticle could be in principle emissive. Studies are awaited to investigate this interesting possibility. Material and methods Millipedes p Frozen Motyxia sequoiae millipedes, previously obtained from California, were graciously provided by J. W. ­Hastings† at Harvard University in 2005 and used in our laboratory for biochemical studies. Fluorescent mil- lipedes Deltatoria brimleii, Deltotaria sp and Euryus orestes were collected during May of 2019 and 2023 at the Highland Biological Station (Highlands, NC) and were kindly identified by Derek Merret (Virginia Technology Natural History Museum). sible biological function for fluorescence and phosphorescence in millipedes l b fl h b d l l l l l Possible biological function for fluorescence and phosphorescence in millipedes Recently, biofluorescence has been suggested to play important signaling ecological role in crepuscular-nocturnal ­mammals23. In nocturnal millipedes, both fluorescence and phosphorescence may have not a readily recognizable biological function, considering they are blind, ruling out an inter-specific function such as sexual attraction, and because they are active just at night, when there is not strong illumination to excite the fluorescence and phosphorescence. Similarly, the coloration may not have an apparent biological function for the same reasons. However, in the case of Motyxia spp millipedes, it was recently demonstrated that bioluminescence has an aposematic function since that millipedes turned dark upon artificial painting their cuticles with black ink were much less prone to ­predation24. Thus a strong pigmentation could be also indicative of an aposematic defensive function, and a biological function could be hypothesized for coloration and fluorescence during the day or twilight, whenever the millipede is exposed to sunlight by a predator, showing an aposematic coloration which could be amplified by fluorescence, similarly to some bird´s plumage. Another possibility that would be worth investigating is whether there is a function during moonlit nights. Are those millipedes more active during such nights? Is moonlight, especially during a full moon, bright enough to excite this fluorescence and phos- phorescence? The moonlit emission spectrum certainly has a considerable proportion of near-UV light that can potentially excite both fluorescence and phosphorescence in these millipedes. In such cases both fluorescence and phosphorescence could amplify visual warning aposematic signals that may deter a predator: after all these millipedes produce and secrete cyanide whenever disturbed, giving off their characteristic and pleasant, albeit dangerous, and sweet almond smell! Relationship between phosphorescence, fluorescence and bioluminescence in millipedes Relationship between phosphorescence, fluorescence and bioluminescence in millipedes Independently of whether or not there is a biological function for the observed phosphorescence in millipedes, such photophysical processes are interesting and may have a relationship with the bioluminescence mechanism https://doi.org/10.1038/s41598-023-47860-9 Scientific Reports | (2023) 13:22171 | www.nature.com/scientificreports/ Fluorescence and phosphorescence spectra l d h h b Fluorescence and phosphorescence spectra were obtained using mainly a Hitachi F4500 spectrofluorometer (Japan). Fluorescence spectra were obtained upon excitation at 364 nm with an excitation window of 2.5–5.0 nm and an emission window of 10 nm. Phosphorescence spectra were scanned from 400 to 700 nm with excitation at 364 nm, excitation window at 10 nm and speed 240 nm/min, using the phosphorescence mode. Bioluminescence and phosphorescence spectra were also obtained with a refrigerated CCD camera provided spectroluminometer LumiSpectra (ATTO, Japan). Phosphorescence spectra in this latter equipment were measured in the high sen- sitivity mode upon pre-irradiation with a SouthWalker lantern provided with Nichia UV LED (Japan) followed by turning off the UV light source. Phosphorescence life‑timeh The phosphorescence life-time was measured using a Hitachi F4500 spectrofluorometer in the module Time scan (Phosphorescence), upon excitation at 364 nm and emission at 525 nm. Photography Ph hi i Photographic images and videos of millipede fluorescence were obtained using a Galaxy S10Plus camera. Images of millipede phosphorescence were obtained using a Canon Ti5 camera with a 100 mm macro lens, and 10 s exposure at 12,200 ISO after UV irradiation using a SouthWalker lantern provided with Nichia UV LED (Japan) during 10 s. Scientific Reports | (2023) 13:22171 | https://doi.org/10.1038/s41598-023-47860-9 www.nature.com/scientificreports/ Supplemental information pp Link for Video-1. Fluorescent Deltatoria bremleii millipede: https://​drive.​google.​com/​file/d/​1TT_​Pajh6​MGCc8​ a9Q6c​saWjD​WFHAq-​Ok_/​view?​usp=​drive_​link Fluorescent compound extraction Bioluminescence and Chemiluminescence spectra Thin Layer Chromatography (TLC)h h Thin Layer Chromatography (TLC) was performed using pre-coated silica-gel 60 sheets (Alugram XtraSIL G, Germany) using methanol 60% in water or ethyl acetate/ethanol/water (5:3:2) as mobile phases at room tem- perature. Fluorescence was revealed using UV irradiation at 370 nm. Fluorescent compound extraction Fluorescent compound extractionl To obtain fluorescent pigments, frozen Deltatoria millipides were allowed to partially thaw, and then laterally opened with a scissor. After removing the still frozen digestive tube, the remaining dorsal (pigmented) and ventral (whitish) cuticles, including legs, were separately ground with a mortar on ice using methanol/1% TFA. The suspension was then centrifuged at 15,000 g during 15 min at 4 °C, and the supernatant used to measure fluorescence spectra and for Thin Layer Chromatography (TLC) analysis. The cuticles were also ground in 50 mM sodium acetate buffer pH 5.8 supplemented with 10 mM EGTA and 0.20 M NaCl, centrifuged and the supernatants used for fluorescence and phosphorescence analysis. Bioluminescence system extraction y In the case of photoprotein extraction from either Motyxia or other fluorescent millipedes, we followed the pro- tocol of ­Shimomura11. The cuticles of 1 or 2 of these frozen millipedes were also excised with scissors using the procedure described above, and grounded in an ice-cold mortar, with an ice-cold extraction buffer consisting of 10 mM sodium acetate buffer pH 5.8, containing 0.2 M NaCl, 10 mM EDTA supplemented with an antiprotease cocktail (Merck). The homogenates were then centrifuged at 15,000 g for 15 min at 4 °C, and the supernatants used for photoprotein in vitro bioluminescence and chemiluminescence luminometric assays and spectra. Bioluminescence and chemiluminescence assaysh y The in vitro bioluminescence was assayed using an adaptation of the protocol described by ­Shimomura11. Inside a luminometer tube, 10–20 µl of crude extract were mixed with a solution consisting of 80–90 µl of 0.10 M Tris–HCL buffer pH 8.5, 2 mM ATP and 4 mM MgSO4. The luminescence output was measured in counts per second (cps) using an ATTO AB220 luminometer (Tokyo, Japan). Chemiluminescence assays were performed by mixing crude and methanolic millipede cuticle extracts with hydrogen peroxide 0.1–3% in buffer and light intensities were measured using an ATTO luminometer. Bioluminescence and Chemiluminescence spectra Bioluminescence and chemiluminescence spectra were measured using a LumiSpectra spectroluminometer (ATTO, Japan). For bioluminescence spectra 10–20 µl of Millipede crude extracts were mixed with a solu- tion consisting of 80–90 µl of 0.10 M Tris–HCL buffer pH 8.5, 2 mM ATP and 4 mM ­MgSO4 inside a lumi- nometer tube. Chemiluminescence spectra were measured upon mixing 2–10 µl of concentrated methanolic cuticle extracts with 100 µl of a solution of potassium superoxide (8 mg/mL) dissolved in anhydrous DMSO (SIGMA-Aldrich). Data availabilityh & Moore, W. Discovery of a glowing millipede in California and the gradual evolution of bioluminescence in Diplopoda PNAS. 112, 6419–6424 (2015). 6. Blum, M. S. & Woodring, J. P. Secretion of benzaldehyde and hydrogen cyanide by the millipede Pachydesmus crassicutis (Wood) Science 138, 512–513 (1962). 7. Means, J. C., Hennen, D. A., Tanabe, T. & Marek, P. E. Phylogenetic systematics of the millipede family Xystodesmidae. Insect Syst Divers. 5, 1–26 (2021). 18. Shimomura, O. A new type of ATP-activated bioluminescent system in the millipede Luminodesmus sequoiae. FEBS Lett. 128, 242 244 (1981) 18. Shimomura, O. A new type of ATP-activated bioluminescent system in the millipede Luminodesmus sequoiae. FEBS Lett. 128, 242–244 (1981). ( ) 19. Shimomura, O. Porphyrin chromophore in Luminodesmus photoprotein. Comp. Biochem. Physiol. 79B, 565–567 (1984). 20. Kuse, M. et al. 7,8-dihydropterin-6-carboxylic acid as light emitter of luminous millipede. Luminodesmus sequeiae. Bioorg. Med. Chem. Lett. 11, 1037–1040 (2001).il 1. Kuse, M., Yanagi, M., Tanaka, E., Tani, N. & Nishikawa, T. Identification of a fluorescent compound in the cuticle of the train millipede Parafrontaria laminate armigera. Biosci. Biotechnol. Biochem. 11, 2307–2309 (2010). 2. Ramos, L. D., Gomes, T. M. V., Stevani, C. V. & Bechara, E. J. H. Mining reactive triplet carbonyls in biological systems. J. Photo chem. Photobiol. B. 243, 112712 (2023).l 23. Olson, E. R. et al. Vivid biofluorescence discovered in the nocturnal Springhare (Pedetidae). Sci. Rep 11, 4125 (2021). 23. Olson, E. R. et al. Vivid biofluorescence discovered in the nocturnal Springhare (Pedetidae). Sci. Rep 11, 4125 (2021). l 24. Marek, P., Papaj, D., Yeager, J., Molina, S. & Moore, W. Bioluminescent aposematism in millipedes. Current Biol. 21, Data availabilityh y The datasets used and/or analysed during the current study are available from the corresponding autho reasonable request. Received: 28 July 2023; Accepted: 19 November 2023 References 1. Viviani, V. R. Bioluminescence in Handbook of Organic Photochemistry and Photobiology (eds. Griesbeck, A., Oelgemöller, M. & Ghetti, F.) 1265–1288 (CRC Press, 2012). Scientific Reports | (2023) 13:22171 | https://doi.org/10.1038/s41598-023-47860-9 www.nature.com/scientificreports/ 3. Sparks, J. S. et al. The covert world of fish biofluorescence: a phylogenetically widespread and phenotypically variable phenomenon. PLoS ONE 9, e83259 (2014).l M. O. Salamanders and other amphibians are aglow with biofluores p gl p 5. Taboada, C., Brunetti, A. E., Pedron, F. N. & Faivovich, J. Naturally occurring fluorescence in frogs. PNAS 114, 3672–3677 (2017 l 6. Taboada, C., Brunetti, A. E., Lyra, M. L. & Bari, S. E. Multiple origins of green coloration in frogs mediated by a novel biliverdin binding serpin. PNAS 117, 18574–18581 (2020). g p ( ) 7. Haddock, S. T. D., Moline, M. A. & Case, J. F. Bioluminescence in the sea. Annu. Rev. Mar. Sci. 2, 293–343 (2010). 7. Haddock, S. T. D., Moline, M. A. & Case, J. F. Bioluminescence in the sea. Annu. Rev. Mar. Sci. 2, 293–343 (2010). 8. Hausmann, F., Arnold, K. E., Marshal, N. J. & Owens, I. P. F. Ultraviolet signals in birds are special. Proc. Royal Soc. 270, 61–67 (2003). 8. Hausmann, F., Arnold, K. E., Marshal, N. J. & Owens, I. P. F. Ultraviolet signals in birds are special. Proc. Royal Soc. 270, 6 (2003). 9. Marshall, J. & Johnsen, S. Fluorescence as a means of colour enhancement. Phyl. Trans. R. Soc. B. 372, 20160335 (2017). y 10. Lourenço, W. L. Fluorescence in scorpions under UV light: can chaelirids be a possible exception?. C. R. Biol. 335, 731–734 (2012) 11. Shimomura, O. Bioluminescence: Chemical Principles and Methods (World Scientific Publishing Co Pte Ltd, 2006). y 10. Lourenço, W. L. Fluorescence in scorpions under UV light: can chaelirids be a possible exception?. C. R. Biol. 335, 731–734 (2 Shimomura, O. Bioluminescence: Chemical Principles and Metho i 12. Yang, Y. G. et al. Room temperature phosphorescence from natural products: christallization matters. Chem. Sci China 56, 1 1182 (2013). ( ) 3. https://​www.​opens​pace.​org/​stori​es/​natur​es-​night-​lights-​learn-​about-​glow-​dark-​organ​isms-​santa-​cruz-​mount​ains). tps://​www.​opens​pace.​org/​stori​es/​natur​es-​night-​lights-​learn-​about p p p g g g g g 14. Hastings, J. H. & Davenport, D. The luminescence of the millipede Luminodesmus sequoia. Biol Bull. 113, 120–128 (1957). h 5. Marek, P. Acknowledgements g I am grateful to Prof. James Costa for allowing my visit to the Highlands Biological Station and discussions, Dr. Derek Hennen from Virginia Tech for kind identification of the millipede specimens and especially Prof. Carl H. Johnson (Vanderbilt University) for his kind support and helpful comments on the manuscript. This work was supported by grants from FAPESP 2010/05426-8 and 2022/04800-0, and CNPq. Author contributionsh The author discovered phosphorescence in millipedes, made the experimental work and wrote the manuscript Competing interests h p g The author declares no competing interests. The author declares no competing interests. © The Author(s) 2023 Additional informationh Supplementary Information The online version contains supplementary material available at https://​doi.​org/​ 10.​1038/​s41598-​023-​47860-9. Supplementary Information The online version contains supplementary material available at https://​doi.​org/​ 10.​1038/​s41598-​023-​47860-9. Correspondence and requests for materials should be addressed to V.R.V. Correspondence and requests for materials should be addressed to V.R.V. Reprints and permissions information is available at www.nature.com/reprints. Reprints and permissions information is available at www.nature.com/reprints. 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The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping
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The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping Jorge Ga´mezID, Germa´n MendozaID, Luis Prado, Abraham BetancourtID H M h Jorge Ga´mezID, Germa´n MendozaID, Luis Prado, Abraham BetancourtID Hugo MerchantID* Jorge Ga´mezID, Germa´n MendozaID, Luis Prado, Abraham BetancourtID, Hugo MerchantID* Instituto de Neurobiologı´a, Universidad Nacional Auto´noma de Me´xico, Campus Juriquilla, Quere´taro, Me´xico Hugo MerchantID* Instituto de Neurobiologı´a, Universidad Nacional Auto´noma de Me´xico, Campus Juriquilla, Quere´taro, Me´xico Instituto de Neurobiologı´a, Universidad Nacional Auto´noma de Me´xico, Campus Juriquilla, Quere´taro, Me´xico * hugomerchant@unam.mx a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 RESEARCH ARTICLE Academic Editor: Robert Zatorre, McGill University, CANADA Academic Editor: Robert Zatorre, McGill University, CANADA Received: September 13, 2018 Accepted: March 19, 2019 Published: April 8, 2019 Copyright: © 2019 Ga´mez et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Received: September 13, 2018 Accepted: March 19, 2019 Published: April 8, 2019 Copyright: © 2019 Ga´mez et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All underlying experimental data used in this study have been deposited in G-Node (https://doid.gin.g-node.org/ d315b3db0cee15869b3d9ed164f88cfa/). Abstract Our motor commands can be exquisitely timed according to the demands of the environ- ment, and the ability to generate rhythms of different tempos is a hallmark of musical cogni- tion. Yet, the neuronal underpinnings behind rhythmic tapping remain elusive. Here, we found that the activity of hundreds of primate medial premotor cortices (MPCs; pre-supple- mentary motor area [preSMA] and supplementary motor area [SMA]) neurons show a strong periodic pattern that becomes evident when their responses are projected into a state space using dimensionality reduction analysis. We show that different tapping tempos are encoded by circular trajectories that travelled at a constant speed but with different radii, and that this neuronal code is highly resilient to the number of participating neurons. Cru- cially, the changes in the amplitude of the oscillatory dynamics in neuronal state space are a signature of duration encoding during rhythmic timing, regardless of whether it is guided by an external metronome or is internally controlled and is not the result of repetitive motor commands. This dynamic state signal predicted the duration of the rhythmically produced intervals on a trial-by-trial basis. Furthermore, the increase in variability of the neural trajec- tories accounted for the scalar property, a hallmark feature of temporal processing across tasks and species. Finally, we found that the interval-dependent increments in the radius of periodic neural trajectories are the result of a larger number of neurons engaged in the pro- duction of longer intervals. Our results support the notion that rhythmic timing during tapping behaviors is encoded in the radial curvature of periodic MPC neural population trajectories. Citation: Ga´mez J, Mendoza G, Prado L, Betancourt A, Merchant H (2019) The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping. PLoS Biol 17(4): e3000054. https://doi.org/10.1371/journal. pbio.3000054 OPEN ACCESS Citation: Ga´mez J, Mendoza G, Prado L, Betancourt A, Merchant H (2019) The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping. PLoS Biol 17(4): e3000054. https://doi.org/10.1371/journal. pbio.3000054 Academic Editor: Robert Zatorre, McGill University, CANADA Introduction Precise timing is a fundamental requisite for a select group of complex actions such as the exe- cution and appreciation of music and dance [1]. In these behaviors, the perception of time intervals is facilitated by the presence of a regular beat in the rhythmic sequence, and individ- ual intervals are encoded relative to this pulse or beat. This is called beat-based timing and serves as a framework for rhythmic entrainment, in which subjects perform movements syn- chronized to music [2–4]. Most of occidental music is organized by a quasi-isochronous pulse and frequently also in a metrical hierarchy, in which the beats of one level are typically spaced at two or three times those of a faster level (i.e., the tempo of one level is 1/2 [march meter] or 1/3 [waltz meter] that of the other), and humans can typically synchronize at more than one level of the metrical hierarchy [5,6]. Rhythmic tapping to an isochronous metronome is the simplest case of beat entrainment [7] and has been thoroughly studied in humans [8,9]. In contrast to the large human flexibility to perceive and entrain to complex beats in music, non- human primates can perceive [10–13] and synchronize to simple isochronous beats [14–16]. On the other hand, other sets of behaviors, such as the interception of a moving target or the production of a single interval, seem to depend on a duration-based timing mechanism, in which the absolute duration of individual time intervals is encoded discretely, like a stopwatch [2,17]. Functional imaging and behavioral studies have suggested the existence of a partially segregated timing neural substrate, with the cerebellum as a key structure for duration-based timing, the basal ganglia as main nuclei for beat-based timing, and medial premotor cortices (MPCs; which include the pre-supplementary motor area [preSMA] and supplementary motor area [SMA]) as a potential master clock for both timing mechanisms [7,18–20]. Yet, the neural substrate for absolute timing, and especially for beat perception and rhythmic entrain- ment, is still largely unknown. Recent advances on the neurophysiology of absolute timing during single interval repro- duction tasks suggest that time is represented in the structured patterns of activation of cell populations in timing areas such as the MPC and the neostriatum [21–24]. The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping data collection and analysis, decision to publish, or preparation of the manuscript. metronome. Using principal component analysis, we projected the time-varying activity of hundreds of neurons into a low-dimensional space. The projected activity of the neural population generated a circular trajectory for every interval produced in the sequence, which travelled at a constant speed but with different radii for different tapping tempos. In addition, the increase in amplitude and variability of the neural trajectories accounted for the scalar property of timing, a generalized feature of temporal processing across tasks and species and which defines a linear relationship between the variability of temporal performance and interval duration. Competing interests: The authors have declared that no competing interests exist. Abbreviations: a.u., arbitrary unit; CC, continuation condition; DAT, Dynamic Attending Theory; dPCA, demixed PCA; EEG, electroencephalogram; MPC, medial premotor cortex; MSE, mean square error; PC, principal component; PCA, principal component analysis; preSMA, pre-supplementary motor area; SC, synchronization condition; SCT, synchronization-continuation task; SI, surprise index; SMA, supplementary motor area; SRTT, serial reaction time task; ST, synchronization task; SVM, support vector machine; TDNN, time-delay neural network; TIND, target interval normalized data; UTND, unit time normalized data. Author summary The ability to extract the regular pulse in music and to respond in synchrony to this pulse is called beat synchronization and is a natural human behavior exhibited during dancing and musical ensemble playing. A part of the brain called the medial premotor cortex has been associated with rhythmic entrainment, and yet the neural basis of this complex behavior is still far from known. In this work, we recorded the neuronal activity from the medial premotor cortices of macaques trained to tap rhythmically to the frequency of a Funding: This work was funded by Consejo Nacional de Ciencia y Tecnologia #236836 and #196, https://www.conacyt.gob.mx/, and Programa de Apoyo a Proyectos de Investigacio´n e Innovacio´n Tecnolo´gica #IN202317, http://dgapa. unam.mx/index.php/impulso-a-la-investigacion/ papiit. The funders had no role in study design, 1 / 32 PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping produced interval. The moving bump repeats itself on each produced interval of the tapping sequence [4,21,28]. Nevertheless, single MPC cells multiplex the interval, the serial order, and task phase of the SCT, showing complex and heterogenous time-varying profiles of activation that make it difficult to understand the neural population mechanisms behind rhythmic tap- ping. A successful approach to determine the latent task variables in cell populations is to proj- ect high-dimensional individual neural activity into a low-dimensional topological space, in order to generate a robust and stable manifold [29]. Recent studies have reconstructed key hid- den task parameters in the neural state population dynamics [30–32]. Thus, the combined use of high-density single unit recordings with dimensional reduction methods have revealed basic organizing principles at the level of the population dynamics, which seem to be extremely complex at the level of individual neurons [29,33]. p Here, we investigated the population dynamics of hundreds of MPC neurons in monkeys performing two isochronous tapping tasks, testing whether low-dimensional state network tra- jectories can act as a neural clock during rhythmic tapping. Using dimensional reduction anal- ysis, we found highly stereotyped neural trajectories that had two main properties during the SCT. First, the three first principal components showed a periodic path for each produced interval. Notably, these oscillatory state trajectories did not overlap across durations, a signa- ture of temporal scaling; instead, they showed a linear increase in their radius and a constant linear speed as a function of the target interval during metronome guidance (synchronization condition [SC]), as well as during internally controlled rhythmic tapping (continuation condi- tion [CC]). Second, the intertrial variability of the trajectories’ radial magnitude also increased as a function of the interval, accounting for a key feature of timing behavior: the scalar prop- erty, which states that the variability of produced or estimated intervals increases linearly as a function of interval duration. These properties were highly resilient to the number of partici- pating neurons and were replicated using simultaneously recorded cells during synchronized tapping, but not during a serial reaction time-control task that precluded rhythmic prediction. Finally, we found a tight correlation between the interval-associated changes in trajectory amplitude and variability during SCT, the number of neurons involved in the sequential tran- sient activation patterns, and the duration of the neural activation periods within these moving bumps. Indeed, moving bumps simulations revealed that scaling the duration of the transient period of activity and increasing the number of neurons participating in the evolving patterns produced an increase in the radius and the variability of the corresponding neural trajectories, replicating the empirical findings. These results suggest that rhythmic timing depends on the radial amplitude of periodic state population trajectories in MPC, which in turn depend on the number of neurons involved and the duration of these cells’ activation periods within moving bumps. Introduction Rather than being quantified in the instantaneous activity of single cells that accumulate elapsed time or encode the time remaining for an action [25–27], the duration of produced intervals depends on the speed at which the neural population response changes. This implies that the activation pro- files are compressed for short and elongated for long intervals due to temporal scaling on the activity of the same population of cells [23,24]. On the other hand, MPC neurons are tuned to the duration and ordinal sequence of rhyth- mic movements produced either in synchrony with a metronome or guided by an endogenous tempo (synchronization-continuation task [SCT]) [4,21]. Remarkably, the time-varying profile of activation of these interval-specific neural circuits forms a moving bump, which is defined as a sequential pattern of responses in which the cells are activated consecutively within a PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 2 / 32 PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 Rhythmic tapping behavior We trained two monkeys (M01 and M02) in the SCT. M01 was also trained in two additional tapping tasks: the synchronization task (ST) and the serial reaction time task (SRTT). During SCT, the animals tapped on a push button in synchronization with a rhythmic metronome for four times, thus producing three intervals (SC phase), followed by three internally generated intervals (CC phase; Fig 1A). In the ST, the monkey produced five intervals guided by a metro- nome, similarly to the SC of SCT (Fig 1B). During the SRTT, the animal pressed the button in response to five brief visual stimuli presented in a sequence but separated by a random inter- stimulus interval, precluding the prediction of the next stimulus-response loop (Fig 1C). Thus, during SCT and ST, the animals entrained their rhythmic movements to a sensory 3 / 32 PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping Fig 1. Tasks. A. SCT. The trial started when the monkey placed his hand on a lever for a variable delay. Then, a visual metronome was presented, and the monkey tapped on a button to produce three intervals of a specific duration following the isochronous stimuli (synchronization phase), after which the animal had to maintain the tapping rate to produce three additional intervals without the metronome (continuation phase). Correct trials were rewarded with an amount of juice that was proportional to the trial length. The instructed target intervals were 450, 550, 650, 850, and 1,000 ms. B. ST. Similar to the synchronization phase of the SCT, the animal had to produce five intervals guided by a visual metronome. The instructed intervals were 450, 550, 650, 750, 850, and 950 ms. C. SRTT. As in ST, the trial started when the monkey placed its hand on a lever for a variable delay. However, in this task, the monkey tapped the button after six stimuli separated by a random interstimulus interval, precluding the temporalization of the tapping behavior. D. Rhythmic tapping behavior Constant error (mean ± SD/2) as a function of target interval during the SC (orange) and CC (red) of the SCT (ANOVA main effect interval, F(4, 1,112) = 61.01, p < 0.0001; main effect task condition, F(1, 1,112) = 43.16, p < 0.0001; interval × condition interaction, F(4, 1,112) = 17.66, p < 0.0001), and the ST (purple) as a function of target interval (ANOVA for 450, 550, 650, and 850 target intervals between SC of the SCT and the ST, main effect interval, F(3, 631) = 4.18, p < 0.01; main effect condition, F(1, 631) = 202.16, p < 0.0001; nonsignificant interval × condition interaction, F(3, 631) = 2.46, p = 0.06). Underlying data are available in https:// doid.gin.g-node.org/d315b3db0cee15869b3d9ed164f88cfa/. CC, continuation condition; SC, synchronization condition; SCT, synchronization-continuation task; SRTT, serial reaction time task; ST, synchronization task. Fig 1. Tasks. A. SCT. The trial started when the monkey placed his hand on a lever for a variable delay. Then, a visual metronome was presented and the monkey tapped on a button to produce three intervals of a specific duration following the isochronous stimuli Fig 1. Tasks. A. SCT. The trial started when the monkey placed his hand on a lever for a variable delay. Then, a visual metronome was presented, and the monkey tapped on a button to produce three intervals of a specific duration following the isochronous stimuli (synchronization phase), after which the animal had to maintain the tapping rate to produce three additional intervals without the metronome (continuation phase). Correct trials were rewarded with an amount of juice that was proportional to the trial length. The instructed target intervals were 450, 550, 650, 850, and 1,000 ms. B. ST. Similar to the synchronization phase of the SCT, the animal had to produce five intervals guided by a visual metronome. The instructed intervals were 450, 550, 650, 750, 850, and 950 ms. C. SRTT. As in ST, the trial started when the monkey placed its hand on a lever for a variable delay. However, in this task, the monkey tapped the button after six stimuli separated by a random interstimulus interval, precluding the temporalization of the tapping behavior. D. PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 Neural state trajectories We characterized the dynamics of the evolving response patterns using the projection of the neural population time-varying activity onto a low-dimensional state space using principal component analysis (PCA) on a population of 1,477 MPC cells recorded during SCT (see Materials and methods, recording locations in S1 Fig). The results showed highly stereotyped trajectories with a strong periodicity in the first three principal components (PCs) (Fig 2A– 2D). Indeed, PC2 and PC3 showed together a cyclic path for each produced interval (Fig 2C and 2D). Each loop in the trajectory corresponded to the periodic network state variation dur- ing the production of the rhythmic tapping sequence of the SCT. The circular trajectories in the plane exhibited the tendency to start at the same position in the phase-space after each tap, suggesting the existence of a movement-triggering point at a particular location in the popula- tion trajectory across durations (see below). Crucially, from this common phase-space loca- tion, longer intervals produced larger state trajectory loops, with a monotonic increase in the trajectory radius as a function of target interval during both the SC and CC (Fig 2E). However, the observed interval-dependent modulations in curvilinear amplitude were not accompanied by modulations of the linear speeds of the periodic neural trajectories, as these remained con- stant across durations (Fig 2F). The same properties were observed in PC1 and when the PCA is computed from a subpopulation of neurons whose activity was task related (see S2 Fig). Hence, contrary to a prototypical temporal scaling, in which there is a decrease in linear speed as a function of interval and similar trajectory paths and traversed distances for different dura- tions [24,34], the present results show that rhythmic timing during the SCT is represented as an increase in curvature radii in the neural network state dynamics. To test the relationship between the radius of the curvature in the neural-state trajectories and the monkeys’ behavior during SC and CC, we split the produced intervals into two groups: those in which the monkeys produced an inter-tap time that was below the 20th percentile, and those with inter-tap times above the 80th percentile [21]. Strikingly, on those intervals in which the monkeys tended to produce shorter inter-tap durations, the state trajectory radius was smaller, and vice versa (Fig 2G). The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping target durations (Fig 1D). Finally, the temporal variability (a measure of timing precision) dur- ing the SCT and ST are depicted in Fig 2H and Fig 4E, respectively. PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 Rhythmic tapping behavior Constant error (mean ± SD/2) as a function of target interval during the SC (orange) and CC (red) of the SCT (ANOVA main effect interval, F(4, 1,112) = 61.01, p < 0.0001; main effect task condition, F(1, 1,112) = 43.16, p < 0.0001; interval × condition interaction, F(4, 1,112) = 17.66, p < 0.0001), and the ST (purple) as a function of target interval (ANOVA for 450, 550, 650, and 850 target intervals between SC of the SCT and the ST, main effect interval, F(3, 631) = 4.18, p < 0.01; main effect condition, F(1, 631) = 202.16, p < 0.0001; nonsignificant interval × condition interaction, F(3, 631) = 2.46, p = 0.06). Underlying data are available in https:// doid.gin.g-node.org/d315b3db0cee15869b3d9ed164f88cfa/. CC, continuation condition; SC, synchronization condition; SCT, synchronization-continuation task; SRTT, serial reaction time task; ST, synchronization task. https://doi.org/10.1371/journal.pbio.3000054.g001 metronome, while in the CC of SCT, this was done to an internal representation of the same rhythm. The asynchronies in the SC of SCT were (mean ± SD: 288.7 ± 70 ms). On the other hand, the SRTT involved similar stimuli, tapping behavior, and sequential structure, but no predictive rhythmic timing was possible. Expectedly, the reaction times were significantly larger in the SRTT than the asynchronies in the ST (mean ± SD: 263 ± 37 ms in the ST and 381 ± 46 ms in the SRTT; ANOVA main effect of task: F(1, 718) = 1443.93, p < 0.0001). The constant error, a measure of timing accuracy that corresponds to the difference between the produced and the instructed interval, was slightly negative during SCT and ST, indicating that the monkeys were able to properly produce the intervals with a small underestimation across PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 4 / 32 Neural state trajectories Another important property of the curvilinear radii in the PCA neural trajectories was that their variability (SD of the trajectory radii) followed the same linear increase as a function of target interval observed in the monkeys’ behavior (Fig 2H). This linear relation between tem- poral variability and interval duration, known as scalar property of interval timing, has been widely reported in the timing literature, and our findings suggest that it depends on the radius of the rotatory dynamical state of MPC neural populations during both SCT conditions. It is important to mention that all the described properties in the neural trajectories are resilient on the methods used to compute the PCs (see S3 Fig). The dynamics in the MPC population activity during the SCT was also characterized using demixed PCA (dPCA; Fig 3, see Materials and methods). This method not only captures most of the variance in the neural data but, most importantly, also decomposes the dependencies of the neural population activity into latent components associated with task parameters [30]. In contrast, PCA only focuses on the total variance explained using orthogonal decomposition. The first dPCA (dPCA1) showed a strong periodic structure with a minimum value around the beginning of each produced interval in the SCT sequence, similar to the findings from the PCA neural trajectories (Fig 2C and 2D). In addition, the dPCA1 showed a strong change in amplitude with target duration (Fig 3A). Because we used time-normalized neural data as PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 5 / 32 The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping Fig 2. Neural population trajectories during SCT and their oscillatory dynamic properties. A, C. Projection of the neural activity in the MPC (1,477 neurons) during the SC of the SCT onto the first (A) or second and third PCs (C). The first three PCs explained the 10.7%, 3.8%, and 2.3% of p p j p y pp g Fig 2. Neural population trajectories during SCT and their oscillatory dynamic properties. A, C. Projection of the neural activity in the MPC (1,477 neurons) during the SC of the SCT onto the first (A) or second and third PCs (C). The first three PCs explained the 10.7%, 3.8%, and 2.3% of Fig 2. Neural population trajectories during SCT and their oscillatory dynamic properties. A, C. Variability (SD) of SCT rotational neural trajectories (orange, mean ± SD, normalized data slope = 0.0019, constant = −1.02, R2 = 0.94, p = 0.005) and the monkeys’ produced intervals (gray, mean ± SD, normalized data slope = 0.005, constant = −0.721, R2 = 0.98, p = 0.0008) as a function of target interval. The Weber increase in tapping variability was not statistically different from the increase in the variability of neural trajectories across target intervals (normalized data, slope t test = 0.86, p = 0.42; constant t test = 1.36, p = 0.22). Underlying data are available in https://doid.gin.g-node.org/d315b3db0cee15869b3d9ed164f88cfa/. a.u., arbitrary unit; CC, continuation condition; MPC, medial premotor cortex; PC, principal component; SC, synchronization condition; SCT, synchronization- continuation task. input to the dPCA, all trials had the same length regardless of the target interval. In this sce- nario, a scaling mechanism should have produced similar dPCAs across durations. Instead, we observed a time-dependent modulation in dPCA1 amplitude. In order to compare the two methods for dimensional reduction, we computed the bin-by-bin distance between the 450-ms and the other four target intervals (Fig 3D) using the PCAs (Fig 3B) and dPCA1 (Fig 3C). The resulting distance profiles are very similar between methods, with a periodic structure whose amplitude mean and variability increased as a function of the target interval (Fig 3E and 3F). Thus, with a separate set of assumptions, the dPCA corroborates the existence of both the periodic structure of the neural state dynamics and a beat-based timing mechanism based on the amplitude modulation of the rotatory population trajectories during SCT. The analyses described above were done on neurons recorded throughout different ses- sions. Thus, as a next step we determine the neural state trajectories on simultaneously recorded cells while monkey M01 performed an ST (Fig 1B) and an SRTT (Fig 1C). This strat- egy not only allows us to validate the data of the SCT on the ST but also permits us to deter- mine population dynamics on a trial-by-trial basis. As in the SCT, the PCA-projected activity during the ST showed periodic state dynamics (Fig 4A; S4A Fig), whereas the SRTT neural tra- jectories were not as periodic (Fig 4B; S4B Fig). The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping the total variance. Each point in the trajectory represents the neural network state at a particular moment. The trajectory completes an oscillatory cycle on every produced interval during the synchronization and continuation phases of the SCT. Target interval in milliseconds is color coded (450, green; 650, blue; 1,000, red). Color progression within each target interval corresponds to the elapsed time. A cube indicates the beginning of each trajectory, while an octahedron indicates the end. B, D. Projection of the neural activity during CC of the SCT onto the first (B) or the second and third (D) PC. Color code is the same as (A). E. Monotonic increase of the radii in the oscillatory neural trajectories during SC (orange, mean ± SD, slope = 0.0009, constant = 0.0679, R2 = 0.9, p = 0.01) and CC (red, mean ± SD, slope = 0.0009, constant = −0.0296, R2 = 0.9, p < 0.01) as a function of target interval. F. Linear speed of neural trajectories during SC (orange, mean ± SD, slope = 0.0001, constant = 7.322, R2 = 0.0007, p = 0.896) and CC (red, mean ± SD, slope = 0.002, constant = 4.049, R2 = 0.354, p = 0.002) as a function of target interval (ANOVA main effect interval, F(4, 39) = 92.15, p < 0.0001; main effect condition, F(1,39) = 381.46, p < 0.0001; interval × condition interaction, F(4, 39) = 15.15, p < 0.0001). The linear speed was similar (SC) or showed a slight increase (CC) with the target interval. G. Neural trajectory radii for the top 20% (red, slope = 0.0011, constant = −0.035, R2 = 0.7, p < 0.0001) and bottom 20% (green, slope = 0.00088, constant = −0.009, R2 = 0.75, p < 0.0001) inter-tap intervals across target intervals. Note that on those intervals in which the monkeys tended to produce shorter inter-tap durations, the state trajectory radius was smaller, and vice versa (ANOVA main effect interval, F(4, 40) = 155.7, p < 0.0001; main effect population, F(1, 40) = 33.3, p < 0.0001; interval × population interaction, F(4, 40) = 3.98, p = 0.008). H. https://doi.org/10.1371/journal.pbio.3000054.g002 Neural state trajectories Projection of the neural activity in the MPC (1,477 neurons) during the SC of the SCT onto the first (A) or second and third PCs (C). The first three PCs explained the 10.7%, 3.8%, and 2.3% of PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 6 / 32 PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 Linear speed of neural trajectories during ST (purple, mean ± SD, slope = 0.0001, constant = 7.322, R2 = 0.0007, p = 0.896) and SRTT (green, mean ± SD, slope = 0.002, constant = 4.049, R2 = 0.354, p = 0.002) did not change as a function of target interval. G. Output of the time-delay neural network (TDNN, in blue) Fig 4. Comparison of ST and SRTT trajectories in simultaneously recorded neurons. A. Neural activity data projected on the PC1 (solid line, linearly detrended) and the correspondent sinusoidal fit (dotted line) during a trial of ST for the target interval of 650 ms. B. Similar to (A) for SRTT. Note that the strong periodic structure of the ST neural trajectory is lost during SRTT for the same population of cells. C. The MSE of the sinusoidal fits during ST (purple) is significantly smaller than during SRTT (green; 60 trials, two-sample t test = −6.78, p < 0.0001). D. Radii of the neural trajectories during ST (purple, slope = 0.000087, constant = 0.055, R2 = 0.619, p < 0.0001) and SRTT (green, nonsignificant linear regression, R2 = 0.0172 and Fig 4. Comparison of ST and SRTT trajectories in simultaneously recorded neurons. A. Neural activity data projected on the PC1 (solid line, linearly detrended) and the correspondent sinusoidal fit (dotted line) during a trial of ST for the target interval of 650 ms. B. Similar to (A) for SRTT. Note that the strong periodic structure of the ST neural trajectory is lost during SRTT for the same population of cells. C. The MSE of the sinusoidal fits during ST (purple) is significantly smaller than during SRTT (green; 60 trials, two-sample t test = −6.78, p < 0.0001). D. Radii of the neural trajectories during ST (purple, slope = 0.000087, constant = 0.055, R2 = 0.619, p < 0.0001) and SRTT (green, nonsignificant linear regression, R2 = 0.0172 and p = 0.489) as a function of target interval. E. Variability of the neural trajectories during ST (purple, data slope = 0.000037, constant = 0.028, R2 = 0.368, p < 0.0001), SRTT (green, nonsignificant linear regression, R2 = 0.0005 and p = 0.903), and temporal variability of the monkeys’ produced intervals (gray, mean ± SD/2, data slope = 0.0009, constant = −0.003, R2 = 0.999, p < 0.0001) across target intervals during ST. F. Radii of the neural trajectories during ST (purple, slope = 0.000087, constant = 0.055, R2 = 0.619, p < 0.0001) and SRTT (green, nonsignificant linear regression, R2 = 0.0172 and p = 0.489) as a function of target interval. E. Variability of the neural trajectories during ST (purple, data slope = 0.000037, constant = 0.028, R2 = 0.368, p < 0.0001), SRTT (green, nonsignificant linear regression, R2 = 0.0005 and p = 0.903), and temporal variability of the monkeys’ produced intervals (gray, mean ± SD/2, data slope = 0.0009, constant = −0.003, R2 = 0.999, p < 0.0001) across target intervals during ST. F. Linear speed of neural trajectories during ST (purple, mean ± SD, slope = 0.0001, constant = 7.322, R2 = 0.0007, p = 0.896) and SRTT (green, mean ± SD, slope = 0.002, constant = 4.049, R2 = 0.354, p = 0.002) did not change as a function of target interval. G. Output of the time-delay neural network (TDNN, in blue) The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping Fig 4. Comparison of ST and SRTT trajectories in simultaneously recorded neurons. A. Neural activity data projected on the PC1 (solid line, linearly detrended) and the correspondent sinusoidal fit (dotted line) during a trial of ST for the target interval of 650 ms. B. Similar to (A) for SRTT. Note that the strong periodic structure of the ST neural trajectory is lost during SRTT for the same population of cells. C. The MSE of the sinusoidal fits during ST (purple) is significantly smaller than during SRTT (green; 60 trials, two-sample t test = −6.78, p < 0.0001). D. Radii of the neural trajectories during ST (purple, slope = 0.000087, constant = 0.055, R2 = 0.619, p < 0.0001) and SRTT (green, nonsignificant linear regression, R2 = 0.0172 and p = 0.489) as a function of target interval. E. Variability of the neural trajectories during ST (purple, data slope = 0.000037, constant = 0.028, R2 = 0.368, p < 0.0001), SRTT (green, nonsignificant linear regression, R2 = 0.0005 and p = 0.903), and temporal variability of the monkeys’ produced intervals (gray, mean ± SD/2, data slope = 0.0009, constant = −0.003, R2 = 0.999, p < 0.0001) across target intervals during ST. F. In fact, the fitting of a normalized sinusoidal function on the first PC was statistically more robust for ST than SRTT (in terms of mean square error [MSE]: Fig 4C), even when the length of the inter-tap PCA-projected activity was matched between different produced intervals (see Materials and methods). Again, the radius of the neural trajectories during the ST showed a significant increase in both mean radius (Fig 4D, purple) and variability (Fig 4E), but a constant linear speed (Fig 4F), as a function of the target interval, reproducing the findings in SCT. In contrast, the radius and variability of the trajectories during SRTT showed small changes across target intervals, with a nonsignificant linear fit as a function of target interval for the three parameters (Fig 4D, 4E and 4F, green). This phenomenological comparison suggests that rhythmic tapping to a metronome depends on the amplitude of the cyclic dynamics of population activity and that the shift from a predic- tive to a reactive behavior during SRTT precludes the organization of periodic population state This phenomenological comparison suggests that rhythmic tapping to a metronome depends on the amplitude of the cyclic dynamics of population activity and that the shift from a predic- tive to a reactive behavior during SRTT precludes the organization of periodic population state trajectories. The simultaneity of the recordings during ST [35] allowed for the decoding of the produced intervals on a trial-by-trial basis. Using a time-delay neural network (TDNN; see Materials and methods) (Fig 4G), we found that an ideal reader of the neural trajectories could predict PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 7 / 32 The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping Fig 4. Comparison of ST and SRTT trajectories in simultaneously recorded neurons. A. Neural activity data projected on the PC1 (solid line, linearly detrended) and the correspondent sinusoidal fit (dotted line) during a trial of ST for the target interval of 650 ms. B. Similar to (A) for SRTT. Note that the strong periodic structure of the ST neural trajectory is lost during SRTT for the same population of cells. C. The MSE of the sinusoidal fits during ST (purple) is significantly smaller than during SRTT (green; 60 trials, two-sample t test = −6.78, p < 0.0001). D. Mean inter-tap Euclidean distance (mean ± SD) between the 450-ms and each target interval for the PCA data using PC1–3, (orange) and dPCA using dPC1 (magenta). There was no significant difference between the slopes of PCA and dPCA (slope t test = 1.97, p = 0.0539) F. Variability of the distance between the 450-ms and each target interval for the PCA (orange) and dPCA (magenta). The variability increased monotonically as a function of the target interval for both analyses. Underlying data are available in https://doid.gin.g-node.org/d315b3db0cee15869b3d9ed164f88cfa/. a.u., arbitrary unit; dPCA, demixed PCA; PC, principal component; PCA, principal component analysis; SCT, synchronization-continuation task. https://doi.org/10.1371/journal.pbio.3000054.g003 Fig 3. dPCA applied to neural population activity during SCT. A, dPC1 of the dPCA of the neural activity associated with the target interval (explains 7.8% of the total variance). Target interval in milliseconds is color coded (see inset A). The neural trajectories show oscillatory activity, and their amplitude varies across target intervals. B,C. Euclidean distance between the first PC of the 450-ms target interval and the first PC of each target interval across time for (B) time- normalized PCA and (C) dPCA. Target interval is color coded as in (A). Two-sample Kolmogorov–Smirnov test on the distributions of PCA and dPCA distances showed nonsignificant differences (p < 0.05) across target intervals. D. Distance calculation diagram for PCA data. The inter-tap trajectories for two target intervals are shown (green, 450 ms; red, 1,000 ms). The 450-ms target interval trajectory is used as the reference for distance calculation. The Euclidean distance between each sequential bin is calculated among the reference interval and the other target intervals trajectories. Both population analyses, PCA and dPCA, produced population signals with similar characteristics. Thus, oscillatory activity, modulation of the amplitude with the target interval, and an intersection close to the tap time are characteristics of the underlying neural population activity, irrespective of the dimension reduction algorithm. E. Mean inter-tap Euclidean distance (mean ± SD) between the 450-ms and each target interval for the PCA data using PC1–3, (orange) and dPCA using dPC1 (magenta). There was no significant difference between the slopes of PCA and dPCA (slope t test = 1.97, p = 0.0539) F. Variability of the distance between the 450-ms and each target interval for the PCA (orange) and dPCA (magenta). The variability increased monotonically as a function of the target interval for both analyses. Underlying data are available in https://doid.gin.g-node.org/d315b3db0cee15869b3d9ed164f88cfa/. The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping trained to decode the duration of produced intervals based on the PC1 neural trajectories (orange) during a target interval of 850 ms. Tapping times are shown in yellow. H. TDNN error, defined as the difference between the produced and the decoded interval, as a function of produced interval. TDNN predicted accurately the performance of the monkey on a trial-by-trial basis (the decoded mean was not statistically different from 0, t test = −0.5228, p = 0.6). Underlying data are available in https://doid.gin.g-node.org/d315b3db0cee15869b3d9ed164f88cfa/. a.u., arbitrary unit; MSE, mean square error; PC, principal component; SRTT, serial reaction time task; ST, synchronization task; TDNN, time-delay neural network. https://doi org/10 1371/journal pbio 3000054 g004 https://doi.org/10.1371/journal.pbio.3000054.g004 accurately the tapping times during ST on 86% of the produced intervals. Indeed, the decoding accuracy was better than the actual percent of correct trials in this demanding task (Fig 4H), supporting the notion that the neural trajectories can robustly predict the rhythmic tapping behavior. Fig 3. dPCA applied to neural population activity during SCT. A, dPC1 of the dPCA of the neural activity associated with the target interval (explains 7.8% of the total variance). Target interval in milliseconds is color coded (see inset A). The neural trajectories show oscillatory activity, and their amplitude varies across target intervals. B,C. Euclidean distance between the first PC of the 450-ms target interval and the first PC of each target interval across time for (B) time- normalized PCA and (C) dPCA. Target interval is color coded as in (A). Two-sample Kolmogorov–Smirnov test on the distributions of PCA and dPCA distances showed nonsignificant differences (p < 0.05) across target intervals. D. Distance calculation diagram for PCA data. The inter-tap trajectories for two target intervals are shown (green, 450 ms; red, 1,000 ms). The 450-ms target interval trajectory is used as the reference for distance calculation. The Euclidean distance between each sequential bin is calculated among the reference interval and the other target intervals trajectories. Both population analyses, PCA and dPCA, produced population signals with similar characteristics. Thus, oscillatory activity, modulation of the amplitude with the target interval, and an intersection close to the tap time are characteristics of the underlying neural population activity, irrespective of the dimension reduction algorithm. E. Linear speed of neural trajectories during ST (purple, mean ± SD, slope = 0.0001, constant = 7.322, R2 = 0.0007, p = 0.896) and SRTT (green, mean ± SD, slope = 0.002, constant = 4.049, R2 = 0.354, p = 0.002) did not change as a function of target interval. G. Output of the time-delay neural network (TDNN, in blue) PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 8 / 32 Distributed nature of the trajectories’ timing information We determined whether we could extract information about the target interval from the neural population dynamics, and how this information was modulated by the size of the neural popu- lation used to compute the trajectories. To this end, we first segregated each segment of the single-dimension trajectory according to the SCT target interval (450, 550, . . . 1,000 ms; see insets in Fig 6A). Then, to capture the shape of the trajectory segments as a single three-dimen- sional coordinate, we applied a second-layer PCA (PCA0) and kept the first three PCs. As a result, we obtained a dot cloud in 3D, in which each point represents a particular produced interval trajectory segment (Fig 6A). We trained support vector machines (SVMs) to classify the cloud of points for the five target intervals of the SCT. We trained the SVM ten times and used 5-fold cross-validation to evaluate the performance of the classifier. On the other hand, each neuron was sorted according to the weight magnitude of the original PCAs. The neurons with the largest PC participation were removed in steps of 10% from the original population size, and the second-layer PCAs were computed on the new trajectories. Finally, the SVM was carried out on the second-layer PCAs for different population sizes (see Fig 6). There was an asymptotic decline in the classifier performance with the removal of a larger percentage of the neural population (Fig 7A). However, even with very small populations (total cells: 15), the classifier was able to extract all SCT target intervals above chance. These results are in line with the idea that the temporal structure of rhythmic behavior depends on a neural population code that is distributed within MPC. The population state dynamics are not related to the tapping kinematics The cyclic and smooth nature of the neural trajectories during ST and SCT sharply contrast with the kinematics of movement (Fig 5A, 5C and 5D), which is characterized by stereotypic tapping movements separated by a dwell period that increased as a function of the target inter- val (Fig 5E; [16,37]). These observations suggest that during rhythmic tapping, an explicit tim- ing mechanism in MPC keeps track of the dwell time by setting in motion a continuous and periodic change in the neural population state. According to this scheme, the tapping com- mand is triggered once the state trajectories get to a specific position in the phase-space that corresponds to the intersection point between the tangent circular paths whose radii increase with the tapping tempo. To test the hypothesis, we computed the distance between a point in state space and the position of the taps in the neural trajectory and found a similar distance across target intervals (Fig 5B, see inset). In addition, the distance between the same point and half inter-tap position increased as a function of target interval (Fig 5B). Therefore, these results support the idea that the neural trajectories behave as tangent circles and encode the dwell time between taps in the PC amplitude and trigger the stereotypic tapping movements once the neural dynamics reach a point in state space (S5 Fig). The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping a.u., arbitrary unit; dPCA, demixed PCA; PC, principal component; PCA, principal component analysis; SCT, synchronization-continuation task. https://doi org/10 1371/journal pbio 3000054 g003 PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 9 / 32 PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 Neural population trajectories and evolving activation patterns The results of the previous section revealed a distributed representation of tapping tempo across MPC cell populations. However, a critical question is what aspects of the time-varying activity defined the changes in amplitude in the neural trajectories as a function of the timed duration [28]. Based on our previous observations [4,21], we hypothesized that the evolving patterns of neural activity could be directly linked with the time-encoding features of the neu- ral trajectories during the SCT. Consequently, to test this idea we first characterized the prop- erties of neuronal moving bumps [21,23,36] during this task. With this information we carried out simulations to determine whether the key features of the moving bumps were linked to the PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 10 / 32 The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping Fig 5. Neural trajectories do not follow the tapping kinematics. A. Diagram of the rotational trajectory of the SCT neural activity during three inter-tap intervals: one 450-ms interval (green) and two 1,000-ms intervals (red). Each tap is numbered and projected in the trajectory as a white circle. A blue triangle marks the beginning, whereas a yellow triangle marks the end of the movement time. The monkeys produced phasic stereotypic movements whilst timing the dwell between taps during SCT [37]. B. Euclidean distance (dt, see inset) between an anchor point (red) and the position of each tap (green, mean ± SD, slope = 0.00007, R2 = 0.0633, p = 0.225), or half of the inter-tap interval position on the neural trajectories (blue, mean ± SD, slope = −0.001, R2 = 0.801, p < 0.0001) across target intervals for SC. A two-way ANOVA detected significant main Fig 5. Neural trajectories do not follow the tapping kinematics. A. Diagram of the rotational trajectory of the SCT neural activity during three inter-tap intervals: one 450-ms interval (green) and two 1,000-ms intervals (red). Each tap is numbered and projected in the trajectory as a white circle. A blue triangle marks the beginning, whereas a yellow triangle marks the end of the movement time. The monkeys produced phasic stereotypic movements whilst timing the dwell between taps during SCT [37]. B. A two-way ANOVA showed significant main effects on kinematic state (movement/dwell duration, F(1, 228) = 1,850.61, p < 0.0001), target interval (F(5, 228) = 272.72, p < 0.0001), and their interaction (F(5, 228) = 236.18, p < 0.0001). Tukey HSD post hoc test showed that dwell durations across intervals were significantly different (p < 0.05). Therefore, the monkey modulated the dwell duration to successfully temporalize her behavior, while the down-push-up sequence of the tapping movement was phasic and stereotypic across target intervals. F. Mean ± SD of the peak speed during the tapping movement as a function of the target interval during ST (ANOVA main effect interval, F(5, 114) = 5.13, p < 0.001). The Tukey HSD post hoc test showed that only the peak speed of the 450-ms target interval trials were significantly different from the 650-, 750-, 850-, and 950-ms trials (p < 0.05). Underlying data are available in https://doid.gin. g-node.org/d315b3db0cee15869b3d9ed164f88cfa/. a.u., arbitrary unit; dh, Euclidean distance of the anchor point to the half inter-tap position; dt, Euclidean distance from the anchor point to the tap position; HSD, honestly significant difference; PC, principal component; SCT, synchronization-continuation task; ST, synchronization task. https://doi.org/10.1371/journal.pbio.3000054.g005 https://doi.org/10.1371/journal.pbio.3000054.g005 observed changes in curvature radius and variability as a function of duration in the neural state trajectories. As expected, a substantial proportion of MPC cells during the SCT showed a progressive pattern of activation in the neuronal population, consisting of a gradual response onset of sin- gle cells within a produced interval (Fig 8, see Materials and methods). This activation pattern started before a tap, migrated during the timed interval, and finished after the next tap (Fig 8). In addition, a similar response profile was repeated in a cyclical manner for the three intervals of SC and the three intervals of CC (Fig 8A and 8B) [4,21]. These findings suggest that rhyth- mic timing can be encoded in the sequential activation of neural populations [23]. A central question is what parameters of the neuronal response profiles are encoding the target interval and the SCT condition. Remarkably, the number of neurons involved in these evolving activa- tion patterns (Fig 8A and 8B, Fig 9C), as well as the duration of neural activation periods (Fig 9D), increased as a function of the target interval. SC showed a larger number of active cells, whereas CC showed a longer activation period. The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping effects on position (F(1, 40) = 1855.72, p < 0.0001), target interval (F(4, 40) = 77, p < 0.0001) and their interaction (F(4, 40) = 63.68, p < 0.0001). Tukey HSD post hoc test showed that the distances of the anchor point to tap and half inter-tap positions were significantly different (p < 0.05). In contrast, the anchor to tap distances across target intervals were not statistically different. Inset: scheme of the distance calculation; red sphere marks the anchor point and two-sample inter-tap trajectories for 550 ms (dark gray) and 1,000 ms (light gray) are shown. The green sphere marks the tap position and the blue sphere marks the half inter-tap position. Thus, the neural trajectories converge on an attractor around the tap time, to later diverge at half the inter-tap interval. Note that these results suggest the existence of tangent circular trajectories that converge in an intersection zone close to the tapping moment, although their amplitude changed as a function of interval. C. Speed of the tapping movement (orange trace) from the second to the sixth tap of ST, and the PC1 projected neural information (cyan) for 26 simultaneously recorded neurons during a trial with a target interval of 550 ms. Taps were represented as yellow squares and stimuli as red circles. Movement and dwell times are depicted in green and magenta, respectively. D. Similar to (C) during an 850-ms target interval (PC1 projected neural information as a yellow trace). E. Mean ± SD of the duration of the movement (green) and the dwell between movements (magenta) across target intervals, computed from the speed profile of the tapping movements. A two-way ANOVA showed significant main effects on kinematic state (movement/dwell duration, F(1, 228) = 1,850.61, p < 0.0001), target interval (F(5, 228) = 272.72, p < 0.0001), and their interaction (F(5, 228) = 236.18, p < 0.0001). Tukey HSD post hoc test showed that dwell durations across intervals were significantly different (p < 0.05). Therefore, the monkey modulated the dwell duration to successfully temporalize her behavior, while the down-push-up sequence of the tapping movement was phasic and stereotypic across target intervals. F. Neural population trajectories and evolving activation patterns Euclidean distance (dt, see inset) between an anchor point (red) and the position of each tap (green, mean ± SD, slope = 0.00007, R2 = 0.0633, p = 0.225), or half of the inter-tap interval position on the neural trajectories (blue, mean ± SD, slope = −0.001, R2 = 0.801, p < 0.0001) across target intervals for SC. A two-way ANOVA detected significant main PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 11 / 32 PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 Mean ± SD of the peak speed during the tapping movement as a function of the target interval during ST (ANOVA main effect interval, F(5, 114) = 5.13, p < 0.001). The Tukey HSD post hoc test showed that only the peak speed of the 450-ms target interval trials were significantly different from the 650-, 750-, 850-, and 950-ms trials (p < 0.05). Underlying data are available in https://doid.gin. g-node.org/d315b3db0cee15869b3d9ed164f88cfa/. a.u., arbitrary unit; dh, Euclidean distance of the anchor point to the half inter-tap position; dt, Euclidean distance from the anchor point to the tap position; HSD, honestly significant difference; PC, principal component; SCT, synchronization-continuation task; ST, synchronization task. effects on position (F(1, 40) = 1855.72, p < 0.0001), target interval (F(4, 40) = 77, p < 0.0001) and their interaction (F(4, 40) = 63.68, p < 0.0001). Tukey HSD post hoc test showed that the distances of the anchor point to tap and half inter-tap positions were significantly different (p < 0.05). In contrast, the anchor to tap distances across target intervals were not statistically different. Inset: scheme of the distance calculation; red sphere marks the anchor point and two-sample inter-tap trajectories for 550 ms (dark gray) and 1,000 ms (light gray) are shown. The green sphere marks the tap position and the blue sphere marks the half inter-tap position. Thus, the neural trajectories converge on an attractor around the tap time, to later diverge at half the inter-tap interval. Note that these results suggest the existence of tangent circular trajectories that converge in an intersection zone close to the tapping moment, although their amplitude changed as a function of interval. C. Speed of the tapping movement (orange trace) from the second to the sixth tap of ST, and the PC1 projected neural information (cyan) for 26 simultaneously recorded neurons during a trial with a target interval of 550 ms. Taps were represented as yellow squares and stimuli as red circles. Movement and dwell times are depicted in green and magenta, respectively. D. Similar to (C) during an 850-ms target interval (PC1 projected neural information as a yellow trace). E. Mean ± SD of the duration of the movement (green) and the dwell between movements (magenta) across target intervals, computed from the speed profile of the tapping movements. In contrast, the neural recruitment lapse, namely the time between pairs of consecutively activated cells (Fig 9E), and the cells’ discharge rate (Fig 9F) did not show statistically significant changes across target intervals and task phases. These results suggest that both the size of the circuits involved in measuring the pas- sage of time and the duration of their activation times are core time-encoding signals in MPC, and suggest the existence of a delicate balance between these two measures to produce the pro- gressive activation profiles of neurons when tapping to a metronome or an internally gener- ated rhythmic signal (Fig 9C and 9D). Next, we simulated evolving patterns of population activity with different response profiles and evaluated their translation onto PCA state space. First, we generated activity patterns on individual units that were complex, heterogenous, and that scaled in time, producing activa- tion periods with the same time-varying activity but different durations (Fig 10A, see Materials and methods) [24]. Then, we simulated population cascade patterns for three consecutive intervals, emulating two key features on the MPC population responses: a gradual response onset of single cells that started before, migrated within, and finished after the end of an inter- val, with a constant overall recruitment of cells over time; and the cyclical repetition of this response profile for the three intervals (Fig 10C and 10D). In addition, Fig 11A shows that neu- rons were added randomly in the intermediate portion of the simulated moving bumps when PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 12 / 32 The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping Fig 6. Robustness in the classifier for SCT target interval using segments of the PCA neural trajectory between taps with different neural population sizes. A-C. Three principal components projection of the second-layer PCA0 applied to each of the six inter-tap neural trajectory segments and the five trial repetitions (see inset) for (A) 100%, (B) 50%, and (C) 1% of the neural population. Each dot in the second-layer PCA0 corresponds to ogy | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 13 / 32 Fig 6. Robustness in the classifier for SCT target interval using segments of the PCA neural trajectory between taps with different neural population sizes. A-C. Simulations with constant values in both parameters produced PCA trajectories with similar radii or variability across interval durations, and a decrease in speed with target interval consistent with the notion of temporal scaling (Fig 10E– 10G, Fig 11B–11E). Furthermore, the scaling of the response duration alone did not reproduce the observed changes in radii and variability across durations in the state trajectories (Fig 11D–11E). These findings indicate not only a close relation between the properties of the sequential neural patterns of activation and the neural state trajectories during rhythmic tap- ping, but also suggest that an increment in the number of neurons engaged in the evolving pat- terns of population activity is fundamental to reproducing the two critical duration-dependent features of the PCA neural population trajectories: the increase in the magnitude and variabil- ity of the radii as a function of target interval. Fig 7. Trajectory classifier robustness across neural population sizes during SCT. A. SVM classifier performance (mean ± SD of percent of correct classifications) for target interval (five instructed intervals) during the SCT task based on the neural trajectory computed from different population sizes. The total initial population size was of 1,477 neurons. Dotted lines correspond to random level. The neurons with the largest PC participation were removed in steps of 10% of the original population size, until reaching 1% of the original population. Inset shows the original time-normalized neural trajectory PC used to generate the second-layer PCA0. B. Point cloud in 3D for the second-layer PCAs’ for target interval. See color code in the inset. Note that the percentage of correct classification decreased as a function of the population size; however, the classification was above chance even for the trajectories based on small cell ensembles. Underlying data are available in https://doid.gin.g-node.org/d315b3db0cee15869b3d9ed164f88cfa/. a.u., arbitrary unit; PC, principal components; PCA, principal component analysis; SCT, synchronization-continuation task; SVM, support vector machine. https://doi.org/10.1371/journal.pbio.3000054.g007 Fig 7. Trajectory classifier robustness across neural population sizes during SCT. A. SVM classifier performance (mean ± SD of percent of correct classifications) for target interval (five instructed intervals) during the SCT task based on the neural trajectory computed from different population sizes. The total initial population size was of 1,477 neurons. Dotted lines correspond to random level. The neurons with the largest PC participation were removed in steps of 10% of the original population size, until reaching 1% of the original population. Three principal components projection of the second-layer PCA0 applied to each of the six inter-tap neural trajectory segments and the five trial repetitions (see inset) for (A) 100%, (B) 50%, and (C) 1% of the neural population. Each dot in the second-layer PCA0 corresponds to PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 13 / 32 The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping an inter-tap trajectory segment. Target interval color in the inset in (A). D-F. Distances between cluster centroids of data projection across target intervals for (D) 100%, (E) 50%, and (F) 1% of the neural population. Underlying data are available in https://doid.gin.g-node.org/ d315b3db0cee15869b3d9ed164f88cfa/. a.u., arbitrary unit; PC, principal component; PCA, principal component analysis; SCT, synchronization- continuation task. https://doi.org/10.1371/journal.pbio.3000054.g006 https://doi.org/10.1371/journal.pbio.3000054.g006 increasing the total number of neurons. The projection of the simulated cascades onto PCA space produced oscillatory trajectories (Fig 10B), whose radii and variability increased but the linear speed was similar with the target interval, as seen in the actual population responses. Importantly, these properties were only followed when the simulated neural cascades included an increase in both the number of neurons and the duration of the activation periods as a func- tion of target interval (Fig 10E and 10F). Simulations with constant values in both parameters produced PCA trajectories with similar radii or variability across interval durations, and a decrease in speed with target interval consistent with the notion of temporal scaling (Fig 10E– 10G, Fig 11B–11E). Furthermore, the scaling of the response duration alone did not reproduce the observed changes in radii and variability across durations in the state trajectories (Fig 11D–11E). These findings indicate not only a close relation between the properties of the sequential neural patterns of activation and the neural state trajectories during rhythmic tap- ping, but also suggest that an increment in the number of neurons engaged in the evolving pat- terns of population activity is fundamental to reproducing the two critical duration-dependent features of the PCA neural population trajectories: the increase in the magnitude and variabil- ity of the radii as a function of target interval. increasing the total number of neurons. The projection of the simulated cascades onto PCA space produced oscillatory trajectories (Fig 10B), whose radii and variability increased but the linear speed was similar with the target interval, as seen in the actual population responses. Importantly, these properties were only followed when the simulated neural cascades included an increase in both the number of neurons and the duration of the activation periods as a func- tion of target interval (Fig 10E and 10F). Inset shows the original time-normalized neural trajectory PC used to generate the second-layer PCA0. B. Point cloud in 3D for the second-layer PCAs’ for target interval. See color code in the inset. Note that the percentage of correct classification decreased as a function of the population size; however, the classification was above chance even for the trajectories based on small cell ensembles. Underlying data are available in https://doid.gin.g-node.org/d315b3db0cee15869b3d9ed164f88cfa/. a.u., arbitrary unit; PC, principal components; PCA, principal component analysis; SCT, synchronization-continuation task; SVM, support vector machine. PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 14 / 32 The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping Fig 8. Overall patterns of activity in cell populations. A,B. Neural activation periods, sorted by their mean peak activation time, during the SCT task for the target intervals of 450 (A) and 850 (B) ms. Each horizontal line corresponds to the onset and duration of the significant activation period of a cell according to the Poisson-train analysis (see Materials and methods). The Poisson-train analysis was carried out on the discharge rate of cells that was warped in relation to the tapping times (seven white vertical lines [4,73]). Note that the number of cells with significant activation periods is larger for the longer target interval. Underlying data are available in https://doid.gin.g-node.org/ d315b3db0cee15869b3d9ed164f88cfa/. SCT, synchronization-continuation task. Fig 8. Overall patterns of activity in cell populations. A,B. Neural activation periods, sorted by their mean peak activation time, during the SCT task for the target intervals of 450 (A) and 850 (B) ms. Each horizontal line corresponds to the onset and duration of the significant activation period of a cell according to the Poisson-train analysis (see Materials and methods). The Poisson-train analysis was carried out on the discharge rate of cells that was warped in relation to the tapping times (seven white vertical lines [4,73]). Note that the number of cells with significant activation periods is larger for the longer target interval. Underlying data are available in https://doid.gin.g-node.org/ d315b3db0cee15869b3d9ed164f88cfa/. SCT, synchronization-continuation task. https://doi org/10 1371/journal pbio 3000054 g008 Fig 8. Overall patterns of activity in cell populations. A,B. Neural activation periods, sorted by their mean peak activation time, during the SCT task for the target intervals of 450 (A) and 850 (B) ms. Discussion The present study supports four conclusions. First, the time-varying discharge rate of MPC cells shows a strong periodic organization when projected onto a two-dimensional state space, generating a circular neural trajectory during each produced interval. The amplitude of this trajectory increases with target duration and is closely related to the rhythmic tapping during the SCT and ST, but not during the reactive tapping of SRTT. Second, the scalar property, a hallmark of timing behavior, was accounted for by the variability of the curvilinear radii in the PCA neural trajectories. Third, the population dynamics for simultaneously recorded MPC cell populations during ST contained information to accurately decode the tapping times on a trial-by-trial basis. Last, there is a strong correlation between the interval-associated changes in radial magnitude and variability of the periodic neural trajectories during SCT and the number of neurons involved in the sequential activation patterns, as well as the duration of their tran- sient periods of activation within these moving bumps. Each horizontal line corresponds to the onset and duration of the significant activation period of a cell according to the Poisson-train analysis (see Materials and methods). The Poisson-train analysis was carried out on the discharge rate of cells that was warped in relation to the tapping times (seven white vertical lines [4,73]). Note that the number of cells with significant activation periods is larger for the longer target interval. Underlying data are available in https://doid.gin.g-node.org/ d315b3db0cee15869b3d9ed164f88cfa/. SCT, synchronization-continuation task. In contrast with the temporal scaling model [24], we found that the neural trajectories do not scale in time, because they present a time-related amplitude modulation with similar linear speed profiles across durations. In line with our observations, neural-network simulations of complex sensorimotor patterns showed that temporal scaling of input stimuli produced curvilinear trajectories that increased in radii for longer intervals [38]. Hence, amplitude modulations in neural population trajectories can be associated with rhythmic timing [39] or complex temporal processing [38]. y g p p p g We found a strong correlation between the duration of the produced intervals and the cur- vilinear amplitude of the MPC neural trajectories during the SCT and ST, and, due to the simultaneity of the recordings in the latter task, we decoded accurately the produced durations on a trial-by-trial basis. In addition, the cyclic and smooth nature of the neural trajectories during ST and SCT sharply contrasts with the tapping kinematics, which are characterized by stereotypic tapping movements separated by a dwell period that increases with the timed inter- val [16,37]. Previous studies have demonstrated that cell populations in premotor and motor cortical areas show rotatory non-muscle-like trajectories that reflect the internal dynamics needed for controlling reaching and cycling [40,41]. Under this scenario, we found evidence supporting the notion that the periodic MPC trajectories during rhythmic tapping encode the dwell between taps in their curvilinear radii and that the tapping command is triggered when- ever the trajectory reaches a specific phase-space, which corresponds to the intersection point between the tangent circular paths. This dynamical geometry contrasts with the neural trajec- tories of medial frontal areas during a single interval reproduction task [34]. In this interval- based paradigm, the state trajectories not only evolve at different speeds but also generate par- allel paths for different timed intervals, depending on the initial conditions of the neural popu- lation dynamics [34]. Thus, the present data are consistent with the notion that timing is encoded in a neural population clock [28,42–45] and puts forward the hypothesis that tempo- ral processing during the entrainment to an isochronous metronome depends on the ampli- tude of tangent circular trajectories in MPC populations. Under this scenario, temporal processing is governed by MPC neural population clocks that switch from temporal scaling of their state dynamics during interval timing to amplitude modulation in their tangent circular trajectories during rhythmic timing. The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping Fig 9. Evolving patterns of activation. A. Neural activation periods for the second produced interval (second and third taps as white vertical lines) during SC for the target interval of 850 ms. The horizontal lines of each row correspond to the onset and extent of the activation periods detected by the Poisson-train analysis. Cells were sorted by their time of peak activity. B. Recruitment lapse as a function of cell number. The activation lapse was the difference in the time of peak activity between contiguous cells in the neural avalanche. The mean activation lapse (±SEM) was 2.98 ± 0.08 ms. C. Number of cells with significant activation periods across target intervals for SC (blue) and CC (red). Avalanches for longer intervals recruited more cells (ANOVA main effect target interval, F(4, 20) = 21.1, p < 0.0001; main effect task condition, F(1, 20) = 6.2, p < 0.02; interval × condition interaction, F(4, 20) = 0.71, p = 0.594). D. Duration of the activation periods during the SC (blue) and CC (red) increased as a function of target intervals. (ANOVA main effect target interval, F(4, 20) = 18.9, p < 0.0001; main effect task condition, F(1, 20) = 26.7, p < 0.0001; interval × condition interaction, F(4, 20) = 1.3, p = 0.268). E. Mean neural recruitment lapse during SC (blue) and CC (red) did not change as a function of target interval (ANOVA main effect target interval, F(4, 20) = 2.7, p = 0.06; main effect task condition, F(1, 20) = 3.4, p = 0.08; interval × condition interaction, F(4, 20) = 0.79, p = 0.55). F. The discharge rate during activation periods in SC (blue) and CC (red) did not vary across target intervals (ANOVA main effect target interval, F(4, 20) = 2.2, p = 0.06; main effect task condition, F(1, 20) = 0.86, p = 0.35; interval × condition interaction, F(4, 20) = 0.92, p = 0.45). Underlying data are available in https://doid.gin.g-node.org/d315b3db0cee15869b3d9ed164f88cfa/. CC, continuation condition; SC, synchronization condition. https://doi.org/10.1371/journal.pbio.3000054.g009 https://doi.org/10.1371/journal.pbio.3000054.g009 https://doi.org/10.1371/journal.pbio.3000054.g009 ST. Furthermore, the switch from predictive rhythmic tapping to a reaction time task (SRTT) produced a profound disorganization in the periodicity of neural trajectories, accompanied by no changes in radial amplitude. PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 Rhythmic timing and the amplitude of neural state trajectories The network state trajectories showed the following properties: they were simple, periodic, exhibited an amplitude modulation according to the timed duration, and were different from the stereotypic kinematics of the phasic tapping movements and the timing control of the dwell between movements in this task [16,37]. Notably, the increases in trajectory amplitude as a function of target interval were observed during the two rhythmic tapping tasks, repro- duced with dPCA, and closely related with the monkeys’ produced intervals during SCT and PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 15 / 32 The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping 16 / 32 PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping Fig 10. Simulations of moving bumps and neural trajectories. A. Activity profile of one simulated neuron during its activation period is scaled for the five simulated durations. B. Neural trajectories generated from the population activity of moving bumps simulations. The number of neurons and activation periods varied across intervals (see Materials and methods). The simulated interval is color coded. Second and third simulated taps are marked as white spheres on each trajectory. C,D. Activation profiles of neurons for three consecutive simulated intervals with durations of 450 ms (C) and 1,000 ms (D). The white vertical lines correspond to the tap events defining the intervals. The activation profiles follow a Gaussian shape of cell recruitment, with slow activation rates at the tails (close to each tap). The number of neurons and the duration of the activation periods increased as a function of simulated interval. E,F,G. Radii (E), variability (F), and linear speed (G) of the neural trajectories generated from simulations. Data from the simulated neural activity with growing numbers of neurons and activation periods (expanding simulation: red), constant duration of activation periods and constant number of neurons (static simulation: orange), and from the actual recorded population during SCT (blue) across target intervals. Note that a constant was added to both simulation data in graphs. (E) Radii for simulation with expanding parameters (red, mean ± SD, slope = 0.0009, R2 = 0.811, p < 0.0001), simulation with static parameters (orange, mean ± SD, nonsignificant linear regression, slope = −0.0001, R2 = 0.811, p = 0.214), and actual neural activity (blue, mean ± SD, slope = 0.0009, R2 = 0.897, p < 0.0001). The slopes of the radius, variability, and linear speed were not statistically different between the simulations with expanding parameters and the actual neuronal trajectories (radius slope t test = 0.15, p = 0.878; variability slope t test = 0.25, p = 0.803; linear speed slope t test = 1.8, p = 0.077). However, the slopes between the simulations with constant parameters and neuronal trajectories showed statistically significant differences (radius slope t test = 9.13, p < 0.0001; variability slope t test = 3.73, p < 0.001; linear speed slope t test = 17.71, p < 0.0001). Underlying data are available in https://doid.gin.g-node.org/d315b3db0cee15869b3d9ed164f88cfa/. a.u., arbitrary unit; PC, principal component; SCT, synchronization-continuation task. htt //d i /10 1371/j l bi 3000054 010 Beat perception in humans is shaped by the temporal structure of extrinsic musical sound and by the metrical interpretation that defines where a subject hears the beat. Thus, the percep- tion of a beat and the corresponding movement entrainment depend on a mental interpreta- tion of the metrics of music. The Dynamic Attending Theory (DAT) is one of the most successful hypotheses to explain these phenomena. According to DAT, it is possible to match the tapping movements to a beat during rhythmic entrainment because the periodic dynamics of music drive our attention [50,51], allowing the prediction of the next pulse in the rhythmic auditory sequence. The DAT suggests that attention is a dynamic process that can be success- fully modeled by internal self-sustained oscillations in the auditory system [52,53]. These inter- nal oscillations generate periodic shifts in attention to the most salient events in the sound signal (the pulse that constructs an isochronous sequence in the musical stream), so that the brain generates rhythmic expectations that correspond to the subjective interpretation of the beat. Indeed, electroencephalogram recordings in auditory areas of humans have shown that the brain oscillates at both the exogenous frequency of stimuli and at the metric interpretation of the beat, providing strong support for DAT [54]. In addition, the perception of an inferred musical beat in humans strongly engages the motor system, including the basal ganglia and the MPC [55,56], supporting the notion that rhythmic perception and entrainment depend on a dynamic interaction between the auditory and motor systems in the brain [15,43,57]. Conse- quently, the present findings add important elements to these ideas, namely, neural popula- tions in the motor system show cyclic dynamics whose period is tightly associated with the tempo of the isochronous metronome, even when the metronome is turned off and the mon- keys continue tapping with the same tempo. Hence, in accordance with DAT, the MPC neural trajectories act as a neural oscillator, with a period similar to the tapping tempo during both the sensory cued and the internally driven rhythmic tapping. Importantly, because MPC is part of both the cortico- basal ganglia and the cortico-cerebellar circuits, it can play an important role in both interval and rhythmic timing and can act as a synergistic context-dependent element within the two core timing systems, as suggested previously [46–49]. 17 / 32 PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 18 / 32 PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 Furthermore, in agreement with the audiomotor hypothesis for beat perception and entrainment, our data suggest that preSMA and SMA generate a periodic and predictive neural population signal that not only times the inter-tap dwell and triggers the rhythmic tapping movement, but also may help the sensory system to expect a specific temporal structure on the metronome [57,58]. However, a couple of cautionary notes are in place here. First, monkeys can perceive and predictively synchronize to isochronous metronomes [11,16,59]. We still do not know what the metrical hierarchy is that monkeys can perceive and entrain to [11], but, definitively, nonhuman primates do not have the flexibility to predictively perceive and entrain to a pulse across the range of tempi and meters observed in humans [6]. Hence, our present data may generalize only to isochronous rhythmic timing in humans. Second, monkeys show a bias to synchronize to visual rather than PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 19 / 32 The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping Fig 11. Moving bump simulation parameters. A. Temporal positions of the activation periods of the neurons that were included to the simulation of the 1,000-ms target interval trial (red), in addition to the position of the activation periods of neurons that also participated in the 450-ms simulation (shaded). B,C. Radius (B) and variability (C) of PCA trajectories generated from moving bump simulations when the number of neurons was modified by a constant number (−100, green; −50, cyan; +50, yellow; and +100, red) from the original number of ( f l f l f l Fig 11. Moving bump simulation parameters. A. Temporal positions of the activation periods of the neurons that were included to the Fig 11. Moving bump simulation parameters. A. Temporal positions of the activation periods of the neurons that were included to the simulation of the 1,000-ms target interval trial (red), in addition to the position of the activation periods of neurons that also participated in the 450-ms simulation (shaded). B,C. A two-way ANOVA on the radius showed significant main effects for number of neurons (F(4, 100) = 10,544.2, p < 0.0001), target interval (F(4, 100) = 4,013.12, p < 0.0001), and their interaction (F(16, 100) = 25.8, p < 0.0001). Tukey HSD post hoc test showed significant differences for the radii of all simulations with different numbers of neurons and for all target intervals (p < 0.05). Additionally, A two-way ANOVA on the variability showed significant main effects for number of neurons (F(4, 100) = 2,421.8, p < 0.0001), target interval (F (4, 100) = 3,476.91, p < 0.0001), and their interaction (F(16, 100) = 22.53, p < 0.0001). Tukey HSD post hoc test showed significant differences for the variability of all simulations with different numbers of neurons (p < 0.05). D,E. Radius (D) and variability (E) of the trajectories generated from neural moving bumps in which the duration of the activation periods was reduced by 50% (short, green) or increased by 50% (long, red) of the original scaled duration (197 ms for 450-ms target interval, 205 ms for 550-ms target interval, 213 ms for 650-ms target interval, 233 ms for 850-ms target interval, and 257 ms for 1,000-ms target interval; blue) while the number of neurons was kept constant at 130 across target intervals. A two-way ANOVA on the variability showed significant main effects for activation duration (F(2, 60) = 3,081.54, p < 0.0001), target interval (F(4, 60) = 2,801.16, p < 0.0001), and their interaction (F(8, 60) = 211.34, p < 0.0001). Tukey HSD post hoc test showed significant differences for all simulations with different activation durations (p < 0.05). In addition, a two-way ANOVA on the variability showed significant main effects for activation duration (F(2, 60) = 1,227.53, p < 0.0001), target interval (F(4, 60) = 257.49, p < 0.0001), and their interaction (F(8, 60) = 24.87, p < 0.0001). Tukey HSD post hoc test showed significant differences for all simulations with different activation durations (p < 0.05). Thus, the number of neurons and the activation duration within moving bumps produce large changes in the radius and variability of the simulated neural trajectories. a.u., arbitrary unit; HSD, honestly significant difference; PCA, principal component analysis. https://doi.org/10.1371/journal.pbio.3000054.g011 https://doi.org/10.1371/journal.pbio.3000054.g011 auditory metronomes [16], whereas humans have a strong entrainment bias towards auditory sequences, including music [1,14]. The scalar property of timing and the state dynamics variability The scalar property states that temporal variability increases linearly as a function of timed duration [60]. This hallmark feature of temporal processing has been documented across many timing tasks and species [20,60–63]. Several computational models based on neural pop- ulation time representations have been implemented to describe this property, including drift diffusion [64,65] and recurrent networks [36,66]. Here, we found that the variability in the radii of neural trajectories increased as a function of target interval during SCT and ST, but remained similar during the SRTT, a task that precludes time prediction while preserving the sensory and tapping components. Therefore, these results suggest that the amplitude of the MPC state-network trajectories is a feasible neural correlate of the scalar property during rhythmic tapping. It has been suggested that the connections between the dor- sal auditory regions and the motor planning areas via parietal cortex are stronger in humans than in nonhuman primates, conferring the latter their larger ability for beat perception and entrainment [15,57]. Therefore, it is quite possible that the neural state dynamics in the audio- motor system of the Homo sapiens are more flexible and complex than what we report here. The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping target intervals. A two-way ANOVA on the radius showed significant main effects for number of neurons (F(4, 100) = 10,544.2, p < 0.0001), target interval (F(4, 100) = 4,013.12, p < 0.0001), and their interaction (F(16, 100) = 25.8, p < 0.0001). Tukey HSD post hoc test showed significant differences for the radii of all simulations with different numbers of neurons and for all target intervals (p < 0.05). Additionally, A two-way ANOVA on the variability showed significant main effects for number of neurons (F(4, 100) = 2,421.8, p < 0.0001), target interval (F (4, 100) = 3,476.91, p < 0.0001), and their interaction (F(16, 100) = 22.53, p < 0.0001). Tukey HSD post hoc test showed significant differences for the variability of all simulations with different numbers of neurons (p < 0.05). D,E. Radius (D) and variability (E) of the trajectories generated from neural moving bumps in which the duration of the activation periods was reduced by 50% (short, green) or increased by 50% (long, red) of the original scaled duration (197 ms for 450-ms target interval, 205 ms for 550-ms target interval, 213 ms for 650-ms target interval, 233 ms for 850-ms target interval, and 257 ms for 1,000-ms target interval; blue) while the number of neurons was kept constant at 130 across target intervals. A two-way ANOVA on the variability showed significant main effects for activation duration (F(2, 60) = 3,081.54, p < 0.0001), target interval (F(4, 60) = 2,801.16, p < 0.0001), and their interaction (F(8, 60) = 211.34, p < 0.0001). Tukey HSD post hoc test showed significant differences for all simulations with different activation durations (p < 0.05). In addition, a two-way ANOVA on the variability showed significant main effects for activation duration (F(2, 60) = 1,227.53, p < 0.0001), target interval (F(4, 60) = 257.49, p < 0.0001), and their interaction (F(8, 60) = 24.87, p < 0.0001). Tukey HSD post hoc test showed significant differences for all simulations with different activation durations (p < 0.05). Thus, the number of neurons and the activation duration within moving bumps produce large changes in the radius and variability of the simulated neural trajectories. a.u., arbitrary unit; HSD, honestly significant difference; PCA, principal component analysis. target intervals. PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 Radius (B) and variability (C) of PCA trajectories generated from moving bump simulations when the number of neurons was modified by a constant number (−100, green; −50, cyan; +50, yellow; and +100, red) from the original number of neurons (208 neurons for 450-ms target interval, 220 neurons for 550-ms target interval, 230 neurons for 650-ms target interval, 270 neurons for 850-ms target interval, and 282 neurons for 1,000-ms target interval; blue) while the activation period was kept constant at 257 ms across PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 20 / 32 The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping moving bumps was constant and was accompanied by an increase in the number of neurons participating in the evolving patterns of population activity. Thus, an optimal reader could estimate the tempo of rhythmic tapping based on two signals: the location of the activity within a bump, in which longer intervals engaged moving bumps composed of a larger number of neurons, and the resetting between consecutive evolving activation patterns [65]. Strikingly, our simulations revealed a tight relation between the scaling of the duration of the transient period of activity, the increase in the number of neurons within moving bumps, and the increase in radius and variability of the corresponding neural trajectories. The simulations also suggest that neurons have the same relative position within a moving bump independently of the timed interval, as seen previously in the rat striatum [23]. Consequently, the increase in neural population size for longer intervals implies incorporation of new cells at intermediate locations within the moving bump [21]. These results not only replicate our empirical observa- tions but also support the notion that the properties of moving bumps, especially the number of participating neurons, can shape the curvilinear amplitude and the corresponding variabil- ity in neural state trajectories during SCT. Subjects Two monkeys (M01 and M02, Macaca mulatta, both males, 5–7 kg BW) were trained to tap on a push button in SCT, ST, and SRTT. The monkeys were monitored daily by the research- ers and the animal care staff to check their conditions of health and welfare. Ethics statement All the animal care, housing, and experimental procedures (protocol 090.A INB) were approved by the Ethics in Research Committee of the Universidad Nacional Auto´noma de Me´xico and conformed to the principles outlined in the Guide for Care and Use of Laboratory Animals (NIH, publication number 85–23, revised 1985). Conclusions Overall, these findings support the notion that the rhythmic timing mechanism is based on the changes in curvature radii of the neural population state dynamics in MPC, with slower tem- pos encoded in larger traversed distances in the tangent periodic neural trajectories, and sug- gest that the variability in these neural trajectories is a feasible neural substrate of the scalar property during rhythmic tapping. The relation between neural trajectories and moving bumps during rhythmic tapping The dynamics of coordinated neural population activity define the evolution of the network state trajectories, which in turn have revealed functional principles in a variety of behaviors that are not evident at the single cell level [24,30,32,67]. Notably, the tapping tempo is strongly mapped in the neural trajectories and is encoded in a distributed fashion, not dependent on a particular response profile of individual neurons. Within this neural population framework, we found large groups of neurons that showed sequential transient activation patterns that tra- versed each produced interval during the SCT. Previous studies have reported moving bumps as a timing mechanism in parietal cortex [68], MPC [4,21], the basal ganglia [23,69,70], and hippocampus [71,72]. For example, the bump activity in the rat striatum during a peak interval task moved progressively slower as the timed interval progressed, providing a functional basis for the decrease in the animals’ timing accuracy as the length of the timed interval increased [23]. In contrast, during the SCT we found that the rate of engagement of the neurons within PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 21 / 32 PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 Neural recordings For the SCT, the extracellular recordings were obtained from the MPC of the monkeys using a system with 7 or 16 independently movable microelectrodes (1–3 MO, Uwe Thomas Record- ing, Germany, S3). Only correct trials were analyzed. All isolated neurons were recorded regardless of their activity during the task, and the recording sites changed from session to ses- sion. At each site, raw extracellular membrane potentials were sampled at 40 kHz. Single-unit activity was extracted from these records using the Plexon offline sorter (Plexon, Dallas, TX). Using the seven-electrode system, the number of simultaneously recorded cells ranged from 5 to 14 cells, whereas with the 16-electrode system the number ranged from 10 to 35 cells during a recording session. In the present paper we analyzed the activity of 1,477 (1,074 of Monkey 1 and 403 of Monkey 2) MPC neurons in both monkeys. The functional properties of some of these cells (1,083 neurons) have been reported previously [20,21,25]. In addition, using a semi- chronic, high-density electrode system [35], 26 and 41 MPC cells were recorded simulta- neously while Monkey 1 was performing the ST and SRTT tasks. All the isolated neurons were recorded regardless of their activity during the SCT, ST, and SRTT, and the recording sites changed from session to session. The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping ST. This task was similar to the synchronization phase of the SCT [16]. The subject had to push a button with a stimulus. Six stimuli with a constant interstimulus were presented (red square with a side length of 5 cm, shown for 33 ms). Thus, the metronome was always present during the task. The target intervals were 450, 550, 650, 750, 850, and 950 ms. Five repetitions were collected for each target interval. SRTT. This task is also described elsewhere [14]. Monkeys were required to push a button each time a stimulus was presented, but in this case the interstimulus interval within a trial was random (picking randomly from the same 450, 550, 650, 750, 850, or 950 ms), precluding the explicit temporalization of tapping (Fig 1B). Monkeys received a reward if the response time to each of the five stimuli was within a window of 200 to 500 ms. The intertrial interval was as ST. Visual (white square with a side length of 5 cm, presented for 33 ms) stimuli were used, and five repetitions were collected. PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 Tasks SCT. The SCT has been described before [14]. Briefly, the monkeys were trained to push a button each time stimuli with a constant interstimulus interval were presented. This resulted in a stimulus-movement cycle (Fig 1A). After four consecutive synchronized movements, the stimuli were eliminated, and the monkeys had to continue tapping with the same interval for three additional intervals. Monkeys received a reward (drops of juice) if each of the intervals produced had an error <30% of the target interval. The daily performance of the monkeys was >70% of correct trials. The amount of juice was proportional to the trial length. Trials were separated by a variable intertrial interval (1.2–4 s). The target intervals, defined by visual sti- muli (red square with a side length of 5 cm, presented for 33 ms), were 450, 550, 650, 850, and 1,000 ms. The target intervals were chosen pseudorandomly within a repetition. Five repeti- tions were collected for each target interval. PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 22 / 32 Neural trajectories Event time normalization and binarization. We developed a time-normalization algo- rithm to align the neural data from different tapping times of different recording sessions in the same relative time framework. For each neuron, we calculated the produced interval (time between two taps). Then, we subtracted the time of the second tap of a produced interval in the task sequence from all spike and stimulus times (eventtimes) and divided them by the pro- duced interval. The tapping times acquired values of minus one and zero, and all the other eventtimes were normalized between these two values. Finally, we added the tap sequence num- ber. Thus, all the normalized values for movement, sensory, and spike events acquired values between zero and seven in an SCT trial, as follows: time normalized event ¼ ðevent time tap timeÞ produced interval þ tap sequence time normalized event ¼ ðevent time tap timeÞ produced interval þ tap sequence time normalized event ¼ ðevent time tap timeÞ produced interval þ tap sequence Therefore, the time range of events between the first and the last tap of the normalized data of a trial (unit time normalized data [UTND]) was the same regardless of the target interval. In addition to the trial relative time framework, we also used the target interval normalized data (TIND), which corresponds to the UTND multiplied by the target interval. This time-normali- zation procedure was not necessary for simultaneously recorded data. Trial binarization. For UTND, TIND, and simultaneously recorded data, we divided the neural data in bins by calculating the discharge rate on consecutive windows of 0.02 units. For UTND, we always got 50 bins between each pair of taps across target intervals, whereas for TIND and the simultaneously recorded data, this number depended on the target interval of the trial. For example, the total number of bins was 23 and 50 for trials with the 450- and 1,000-ms intervals, respectively. The binned data of each neuron were divided by the maxi- mum discharge rate of that particular neuron across all repetitions and target intervals of the SCT. We did not use this time-normalization algorithm on the ST and SRTT data. Principal component coefficients matrix. The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping period is statistically different from the average discharge rate r, considering that the firing of the cell is following a nonhomogenous Poisson process (see also [73]). The detection of activa- tion periods above randomness has been described previously [4,74]. Importantly, the Pois- son-train analysis provided the response-onset latency and the activation period for each cell and for each combination of target interval/serial order. Y ¼ PX Y ¼ PX Hence, we first calculated the matrix P using a matrix X that includes all trials and target interval combinations for the visual SCT of our UTND cell population. Using this P on other data guarantees that the same transformation is applied to different neural activity sets. There- fore, using the UTND framework we avoided over- or underrepresentation of the information for different target intervals, due to the constant total number of bins across conditions. Neural activation periods We used the Poisson-train analysis to identify the cell activation periods within each interval defined by two subsequent taps. This analysis determines how improbable it is that the number of action potentials within a specific condition (i.e., target interval and ordinal sequence) was a chance occurrence. For this purpose, the actual number of spikes within a time window was compared with the number of spikes predicted by the Poisson distribution derived from the mean discharge rate during the entire recording of the cell. The measure of improbability was the surprise index (SI), defined as follows: SI ¼ logP where P was defined by the Poisson equation: P ¼ erT X 1 i¼n ðrTÞ i i! where P is the probability that, given the average discharge rate r, the spike train for a produced interval T contains n or more spikes in a trial. Thus, a large SI indicates a low probability that a specific elevation in activity was a chance occurrence. This analysis assumes that an activation PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 23 / 32 Neural trajectories Given a linear transformation of a matrix X into a matrix Y, such that each dimension of Y explains variance of the original data X in descending order, PCA can be described as the search for matrix P that transforms X into Y, as follows: PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping trial allowed the comparison of trajectories for different trials and tasks. A locally weighted scatterplot smoothing function was applied to the columns of the Y matrix. The first three dimensions of Y were used to generate graphical three-dimensional trajectories, while the first eight dimensions, which explained at least 1% of the variance, were used for the other analysis. Trajectory radius and variability The first three PCs explained 10.7%, 3.8%, and 2.3% of the total variance. These three first PCs produced highly stereotyped trajectories with a strong periodicity. In addition, the PC2 and PC3 showed a strong oscillatory structure with a phase difference of π/2 radians during SCT. For these two PCs, we calculated the centroids of the segments of trajectories between adjacent taps. We measured the radius of the 2D trajectory segment as the mean of the Euclidean dis- tances between the centroid and each point in the trajectory segment. The variability of the tra- jectory was calculated as the standard deviation of the Euclidean distances between the centroid and each point in the trajectory segment across the six serial order elements (three of the SC and three of the CC) for each target interval. Accordingly, the temporal variability of the behavior for each target interval was computed as the standard deviation of the produced intervals within a trial, namely the across-six-serial-order elements of the SCT. Neural trajectory decoder We trained a TDNN [75] to decode the produced intervals from the first PC of the simulta- neously recorded neural activity during ST. The TDNN architecture had an input layer with 20 time delays and one hidden 10-unit layer. The output layer consisted of a single unit that was trained to generate a value of 1 when a tap occurred, or 0 otherwise. We trained the net- work using a Bayesian regularization backpropagation algorithm that minimized the mean squared error of the output. The tap time was defined as the time of the peak of the neural net- work output higher than a threshold of 0.12. We considered a correctly decoded interval when the decoded and the produced taps times’ difference was less than 60 ms. We used 5-fold cross-validation to evaluate the performance of the neural network. PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 Generating neural trajectories The TIND information for every trial of all neurons constituted the columns of the X’ matrix. The principal component coefficients matrix P were multiplied by the X’ matrix to transform the neural data into the space of the original Y. Using the same transformation matrix for each PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 24 / 32 SVM classifier We were interested in studying the relation between the neural trajectory dynamics and the instructed interval of the SCT (450 ms, 550 ms, . . . 1,000 ms). Therefore, we first normalized the length of each segment of the first eight PCs of the neural trajectory associated with a pro- duced interval (the time between two taps) to 30 bins (see inset, Fig 7A). This step was neces- sary to avoid a bias associated with the length of the segment. Then, we applied a second-layer PCA0 to each of the original neural trajectory segments for each PC independently. We kept the first three PCs, as they explained 96% of the variance. As a result, a point in a new three- dimensional coordinate for each 30-bin trajectory segment was obtained (see Fig 7B). In order to assess which PC had more information about each of the SCT parameters, we carried out a classification procedure for each PC using an SVM algorithm [76]. Each classifier was retrained 10 times, and we used 5-fold cross-validation to evaluate the performance of the clas- sifier. Thus, we identified the PC with more information for each SCT parameter and called it best-PC. Additionally, we were interested in studying how the size of the neural population used to generate the PCA affected the information contained in the trajectory. We sorted each neuron according to the magnitude of the PCA weights for the best-PC. We iteratively removed the activity of 10% of the neurons with the largest PCA weights for the best-PC until reaching 1% (15 total neurons). Finally, for each population size, we computed the second-layer PCAs on the new trajectories and the corresponding SVM classification. Oscillatory activity analysis To characterize the phase, frequency, and amplitude of the neural trajectories, we calculated a series of nonlinear regression models over the residuals of linear regressions on the first PC projected data. Each inter-tap segment of the projected data was resampled to 30 bins and time normalized to 1 s before calculating the regressions. The general function of the nonlinear models was as follows: PC ¼ a  sineð2p  t þ cÞ þ d where t is time. In addition, the parameter a is the amplitude of the oscillatory function, c the phase offset, and d is a constant. For each trial of both tasks (ST and SRTT), we calculated the MSE. The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 dPCA The dPCA method finds separate decoder (F) and encoder (D) matrices for each task parame- ter (;) by minimizing the loss function, LdPCA ¼ X ; kX; F;D;Xk 2 LdPCA ¼ X ; kX; F;D;Xk 2 where X is a linear decomposition of the data matrix, which contains the instantaneous firing rate of the recorded neurons, into parameter-specific averages: where X is a linear decomposition of the data matrix, which contains the instantaneous firing rate of the recorded neurons, into parameter-specific averages: X ¼ X ; X; þ Xnoise The decoder and encoder axes permit us to reduce the data into a few components captur- ing the majority of the variance of the data dependent on each task parameter [30]. We used the TIND resampled to 30 bins for all target intervals as the input data to the dPCA, and the target interval as the marginalization parameter. Therefore, the length of all the trials for all target intervals was the same. We calculated the bin-by-bin Euclidean distance between the 450-ms first PC and all the target intervals using the PCA and dPCA analyses. PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 25 / 32 Supporting information S1 Fig. Location of the silicon shank for the MPC recordings in Monkey 1 during the ST. MRI cortical surface reconstruction of the macaque brain and the recording position of the Buszaki-64 silicon shank over MPC. The green line corresponds to the anterior-posterior loca- tion of the spur of the arcuate sulcus that divides preSMA from SMA. The silicon shank was implanted according to this landmark, so that four more anterior shanks were located in pre- SMA and other four posterior shanks in SMA. For the recording locations of MPC in Monkeys 1 and 2 during SCT, see Fig 1B of Merchant and colleagues, 2011. AS, arcuate sulcus; CS, cen- tral sulcus; IPS, intraparietal sulcus; MPC, medial premotor cortex; preSMA, pre-supplemen- tary motor cortex; PS, principal sulcus; SMA, presupplementary motor cortex proper; ST, synchronization task. S2 Fig. Neural population trajectories during SCT from a subpopulation of cells with task- related activity. The PCA was performed on the time-varying activity of 104 cells that showed at least 15 activation periods on the Poisson-train analysis across the five target durations and six serial order elements of the SCT. The first three PCs explained 32.5% of the total variance. A. Projection of the neural activity during the SC and CC of SCT onto the first three PCs. The trajectory completes an oscillatory cycle on every produced interval during the synchroniza- tion and continuation phases of the SCT. Target interval in milliseconds is color coded (450, green; 650, blue; 1,000, red). Color progression within each target interval corresponds to the elapsed time. A cube indicates the beginning of each trajectory, while an octahedron indicates the end. B. Linear increase of the radii in the oscillatory neural trajectories during SC and CC (mean ± SD, slope = 0.0003, constant = 0.2, R2 = 0.7, p < 0.0001) as a function of target inter- val. C. Linear speed of neural trajectories during SC and CC (mean ± SD, slope = −0.002, con- stant = 6.3, R2 = 0.42, p = 0.001) as a function of target interval. D. Variability of neural trajectories (mean ± SD, normalized data slope = 0.0002, constant = −0.05, R2 = 0.87, p < 0.0001) as a function of target interval. Underlying data are available in https://doid.gin.g- node.org/d315b3db0cee15869b3d9ed164f88cfa/. CC, continuation condition; PC, principal component; PCA, principal component analysis; SC, synchronization condition; SCT, syn- chronization-continuation task. S3 Fig. The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping Moving bumps simulations In order to investigate how the properties of the pattern of neuronal activation affected the generation of population neuronal trajectories, we generated five repetitions of simulations of neuronal activity for each target interval. The individual neuronal activation period was com- posed of the sum of 20 random gamma functions. The activation period was constant for all the neurons on one simulation, but varied with the target interval: 197-, 205-, 213-, 233-, and 257-ms activation durations for 450-, 550-, 650-, 850-, 1,000-ms target intervals, respectively. The initial activation time for each neuron was adjusted so that the population activation rate followed a Gaussian function as to produce a moving bump pattern. The number of neurons in the simulation was incremented according to the target interval (450 ms, 108 neurons; 550 ms, 120 neurons; 650 ms, 130 neurons; 850 ms, 170 neurons; 1,000 ms, 182 neurons). Fig 11A shows neurons were added randomly in the intermediate portion of the moving bumps. Movement kinematics We applied the Lucas-Kanade optic flow method to measure the monkey’s arm speed during the ST. This method calculates a flow field from the intensity changes between two consecutive video frames. The analyzed video was recorded with a Microsoft Kinect for Windows camera with a 640 × 480 resolution. The optic flow method was applied to a smaller area of 141 × 141 pixels from the original video that contained the monkey’s arm during the whole trial, and no other moving objects. The arm’s movement velocity vector was calculated across all frames as the magnitude of the sum of all the individual flow fields vectors whose magnitude was larger than a predefined threshold. The velocity vector was calculated from the first to the last tap on each correct trial. We reported the speed as the magnitude of the velocity vector. Posteriorly, the kinematic state of the arm was tagged as movement when the velocity vector was larger than a threshold or dwell otherwise. The tagging algorithm considered a change on the kine- matic state when the new state lasted longer than three consecutive frames. PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 26 / 32 (H) PC2, nonsignificant linear regression, R2 = 0.089, p = 0.145, ANOVA main effect target interval, F(4, 20) = 8.18, p < 0.001. Underlying data are available in https://doid. gin.g-node.org/d315b3db0cee15869b3d9ed164f88cfa/. PC, principal component; PCA, princi- pal component analysis; SCT, synchronization-continuation task. (TIF) C,D. Coefficients and trajectories are computed using time-normalized data. (C) PC1, data slope = 0.0012, constant = −0.651, R2 = 0.902, p < 0.0001, ANOVA main effect target interval, F(4, 20) = 875.21, p < 0.0001. (D) PC1, data slope = 0.0048, constant = −1.638, R2 = 0.98, p < 0.0001, ANOVA main effect target interval, F(4, 20) = 390.94, p < 0.0001. E,F. Coefficients and trajectories are computed using actual time data. (E) PC1, data slope = 0.00084, constant = −0.225, R2 = 0.899, p < 0.0001, ANOVA main effect target interval, F(4, 20) = 332.76, p < 0 0001 (F) PC1 data slope 0 0034 constant 0 641 R2 0 686 p < 0 0001 ANOVA C,D. Coefficients and trajectories are computed using time-normalized data. (C) PC1, data slope = 0.0012, constant = −0.651, R2 = 0.902, p < 0.0001, ANOVA main effect target interval, F(4, 20) = 875.21, p < 0.0001. (D) PC1, data slope = 0.0048, constant = −1.638, R2 = 0.98, p < 0.0001, ANOVA main effect target interval, F(4, 20) = 390.94, p < 0.0001. E,F. Coefficients and trajectories are computed using actual time data. (E) PC1, data slope = 0.00084, constant = −0.225, R2 = 0.899, p < 0.0001, ANOVA main effect target interval, F(4, 20) = 332.76, p < 0.0001. (F) PC1, data slope = 0.0034, constant = 0.641, R2 = 0.686, p < 0.0001, ANOVA main effect target interval, F(4, 20) = 100.04, p < 0.0001. G,H. Same as (A,B) but using non- normalized firing rate data to calculate the trajectories. (G) PC2, data slope = 0.175, con- stant = 62.162, R2 = 0.625, p < 0.0001, ANOVA main effect target interval, F(4, 20) = 27.58, p < 0.0001. (H) PC2, nonsignificant linear regression, R2 = 0.089, p = 0.145, ANOVA main effect target interval, F(4, 20) = 8.18, p < 0.001. Underlying data are available in https://doid. gin.g-node.org/d315b3db0cee15869b3d9ed164f88cfa/. PC, principal component; PCA, princi- pal component analysis; SCT, synchronization-continuation task. (TIF) S4 Fig. State trajectories during ST and SRTT using simultaneously recorded neurons. A, B. Three-dimensional neural dynamics trajectory of 650-ms single ST (A) and SRTT (B) inter- vals. The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping fitted a sine function on each of the first 10 PCs and measured their amplitude and speed. For all the possible normalization combinations, we found at least one of the first three PCs that showed a robust fit of the sine function that was accompanied by a monotonic increase in the mean and the variability of the trajectory radius and a similar speed across target intervals. Here, we show only one PC for each normalization combination (see A, C, E, G). (A-F) These were generated using normalized firing rate data to calculate the trajectories. The left row cor- responds to PC radial amplitude and the right row to the PC linear speed. A,B. Coefficients computed with time normalized but trajectories calculated on actual time bins, as presented across this paper for SCT. (A) PC amplitude increased with target interval: PC3, data slope = 0.00081, constant = 0.011, R2 = 0.899, p < 0.0001, ANOVA main effect target interval, F(4, 20) = 128.69, p < 0.0001. (B) PC linear speed is similar across target intervals: PC3, non- significant linear regression, R2 = 0.07, p = 0.201, ANOVA main effect target interval, F(4, 20) = 22.12, p < 0.0001. C,D. Coefficients and trajectories are computed using time-normalized data. (C) PC1, data slope = 0.0012, constant = −0.651, R2 = 0.902, p < 0.0001, ANOVA main effect target interval, F(4, 20) = 875.21, p < 0.0001. (D) PC1, data slope = 0.0048, constant = −1.638, R2 = 0.98, p < 0.0001, ANOVA main effect target interval, F(4, 20) = 390.94, p < 0.0001. E,F. Coefficients and trajectories are computed using actual time data. (E) PC1, data slope = 0.00084, constant = −0.225, R2 = 0.899, p < 0.0001, ANOVA main effect target interval, F(4, 20) = 332.76, p < 0.0001. (F) PC1, data slope = 0.0034, constant = 0.641, R2 = 0.686, p < 0.0001, ANOVA main effect target interval, F(4, 20) = 100.04, p < 0.0001. G,H. Same as (A,B) but using non- normalized firing rate data to calculate the trajectories. (G) PC2, data slope = 0.175, con- stant = 62.162, R2 = 0.625, p < 0.0001, ANOVA main effect target interval, F(4, 20) = 27.58, p < 0.0001. Supporting information Effect of timing and firing rate normalization on the amplitude and speed of neural trajectories. We used different combinations of the time and firing rate normalization of the neural data in order to calculate the PCA coefficients and then the neural trajectories. We 27 / 32 PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping Conceptualization: Jorge Ga´mez, Hugo Merchant. Conceptualization: Jorge Ga´mez, Hugo Merchant. Conceptualization: Jorge Ga´mez, Hugo Merchant. Data curation: Jorge Ga´mez, Abraham Betancourt, Hugo Merchant. Formal analysis: Jorge Ga´mez, Abraham Betancourt, Hugo Merchant. Funding acquisition: Hugo Merchant. Investigation: Jorge Ga´mez, Germa´n Mendoza, Luis Prado, Hugo Merchant. Methodology: Jorge Ga´mez, Germa´n Mendoza, Luis Prado, Hugo Merchant. Project administration: Luis Prado. Data curation: Jorge Ga´mez, Abraham Betancourt, Hugo Merchant. Data curation: Jorge Ga´mez, Abraham Betancourt, Hugo Merchant. Software: Jorge Ga´mez, Abraham Betancourt, Hugo Merchant. Supervision: Germa´n Mendoza, Luis Prado, Hugo Merchant. Supervision: Germa´n Mendoza, Luis Prado, Hugo Merchant. Validation: Hugo Merchant. Validation: Hugo Merchant. Visualization: Hugo Merchant. Writing – original draft: Jorge Ga´mez, Hugo Merchant. Writing – review & editing: Jorge Ga´mez, Germa´n Mendoza. Acknowledgments We thank Victor de LaFuente, Ranulfo Romo, and Roman Rossi for their fruitful comments on the manuscript. We also thank Raul Paulı´n for his technical assistance. Jorge Ga´mez is a doctoral student from Programa de Doctorado en Ciencias Biome´dicas, Universidad Nacional Auto´noma de Me´xico (UNAM), and received fellowship 339118 from CONACYT. PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 Elapsed time is color coded. The previous and the next taps are marked as red and white spheres, respectively. The stimuli are marked as a white pyramid. Underlying data are available in https://doid.gin.g-node.org/d315b3db0cee15869b3d9ed164f88cfa/. SRTT, serial reaction time task; ST, synchronization task. (TIF) S5 Fig. State trajectory progress during SCT. A,B. One trajectory loop for the second pro- duced interval of the (A) SC and (B) CC, during 450-ms (dark gray) and a 1,000-ms (light gray) target intervals. Trajectory progression marked as colored spheres is as follows: previous tap (green), first inter-tap quarter (cyan), second inter-tap quarter/half interval (blue), third inter-tap quarter (yellow), and next tap (red). Therefore, the neural trajectories follow circular paths with different radii that increase according to the target interval, but with similar speed profiles. Underlying data are available in https://doid.gin.g-node.org/ d315b3db0cee15869b3d9ed164f88cfa/. CC, continuation condition; SC, synchronization con- dition; SCT, synchronization-continuation task. (TIF) S5 Fig. State trajectory progress during SCT. A,B. One trajectory loop for the second pro- duced interval of the (A) SC and (B) CC, during 450-ms (dark gray) and a 1,000-ms (light gray) target intervals. Trajectory progression marked as colored spheres is as follows: previous tap (green), first inter-tap quarter (cyan), second inter-tap quarter/half interval (blue), third inter-tap quarter (yellow), and next tap (red). Therefore, the neural trajectories follow circular paths with different radii that increase according to the target interval, but with similar speed profiles. Underlying data are available in https://doid.gin.g-node.org/ d315b3db0cee15869b3d9ed164f88cfa/. CC, continuation condition; SC, synchronization con- dition; SCT, synchronization-continuation task. (TIF) 28 / 32 PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping 11. Honing H, Bouwer FL, Prado L, Merchant H. Rhesus Monkeys (Macaca mulatta) Sense Isochrony in Rhythm, but Not the Beat: Additional Support for the Gradual Audiomotor Evolution Hypothesis. Front. Neurosci. 2018; 12: 475. https://doi.org/10.3389/fnins.2018.00475 PMID: 30061809 12. Hoeschele M, Merchant H, Kikuchi Y, Hattori Y, ten Cate C. Searching for the origins of musicality across species. Philos Trans R Soc Lond B Biol Sci. 2015; 370(1664): 20140094. https://doi.org/10. 1098/rstb.2014.0094 PMID: 25646517 13. Ayala YA, Lehmann A, Merchant H. Monkeys share the neurophysiological basis for encoding sound periodicities captured by the frequency- following response with humans. Sci Rep. 2017; 7(1): 16687. https://doi.org/10.1038/s41598-017-16774-8 PMID: 29192170 14. Zarco W, Merchant H, Prado L, Mendez JC. Subsecond timing in primates: comparison of interval pro- duction between human subjects and rhesus monkeys. J Neurophysiol. 2009; 102(6): 3191–3202. https://doi.org/10.1152/jn.00066.2009 PMID: 19812296 15. Merchant H, Honing H. Are non-human primates capable of rhythmic entrainment? Evidence for the gradual audiomotor evolution hypothesis. Front Neurosci. 2014; 7: 274. https://doi.org/10.3389/fnins. 2013.00274 PMID: 24478618 16. Ga´mez J, Yc K, Ayala YA, Dotov D, Prado L, Merchant H. Predictive rhythmic tapping to isochronous and tempo changing metronomes in the nonhuman primate. Ann N Y Acad Sci. 2018; 1–20. https://doi. org/10.1111/nyas.13671 PMID: 29707785 17. Merchant H, Georgopoulos AP. Neurophysiology of Perceptual and Motor Aspects of Interception. J Neurophysiol. 2006; 95(1): 1–13. https://doi.org/10.1152/jn.00422.2005 PMID: 16339504 18. Kotz SAE, Schwartze M. Differential Input of the Supplementary Motor Area to a Dedicated Temporal Processing Network: Functional and Clinical Implications. Front Integr Neurosci. 2011; 5: 86. https:// doi.org/10.3389/fnint.2011.00086 PMID: 22363269 19. Merchant H, Harrington DL, Meck WH. Neural Basis of the Perception and Estimation of Time. Annu Rev Neurosci. 2013; 36: 313–336. https://doi.org/10.1146/annurev-neuro-062012-170349 PMID: 23725000 20. Merchant H, Pe´rez O, Zarco W, Ga´mez J. Interval tuning in the primate medial premotor cortex as a general timing mechanism. J Neurosci. 2013; 33(21): 9082–9096. https://doi.org/10.1523/ JNEUROSCI.5513-12.2013 PMID: 23699519 21. Crowe DA, Zarco W, Bartolo R, Merchant H. Dynamic Representation of the Temporal and Sequential Structure of Rhythmic Movements in the Primate Medial Premotor Cortex. J Neurosci. 2014; 34(36): 11972–11983. https://doi.org/10.1523/JNEUROSCI.2177-14.2014 PMID: 25186744 22. Bartolo R, Prado L, Merchant H. Information Processing in the Primate Basal Ganglia during Sensory- Guided and Internally Driven Rhythmic Tapping. J Neurosci. 2014; 34(11): 3910–3923. https://doi.org/ 10.1523/JNEUROSCI.2679-13.2014 PMID: 24623769 23. Mello GBM, Soares S, Paton JJ. PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 References 1. Patel AD. The Evolutionary Biology of Musical Rhythm: Was Darwin Wrong? PLoS Biol. 2014; 12(3): 1– 6. https://doi.org/10.1371/journal.pbio.1001821 PMID: 24667562 2. Teki S, Grube M, Kumar S, Griffiths TD. Distinct neural substrates of duration-based and beat-based auditory timing. J Neurosci. 2011; 31(10): 3805–3812. https://doi.org/10.1523/JNEUROSCI.5561-10. 2011 PMID: 21389235 3. Grahn JA. Neuroscientific Investigations of Musical Rhythm: Recent Advances and Future Challenges. Contemp Music Rev. 2009; 28(3): 251–277. https://doi.org/10.1080/07494460903404360 3. Grahn JA. Neuroscientific Investigations of Musical Rhythm: Recent Advances and Future Challenges. Contemp Music Rev. 2009; 28(3): 251–277. https://doi.org/10.1080/07494460903404360 4. Merchant H, Pe´rez O, Bartolo R, Me´ndez JC, Mendoza G, Ga´mez J, et al. Sensorimotor neural dynam- ics during isochronous tapping in the medial premotor cortex of the macaque. Eur J Neurosci. 2015; 41 (5): 586–602. https://doi.org/10.1111/ejn.12811 PMID: 25728178 5. Phillips-Silver J, Trainor LJ. Hearing what the body feels: Auditory encoding of rhythmic movement. Cognition. 2007; 105(3): 533–546. https://doi.org/10.1016/j.cognition.2006.11.006 PMID: 17196580 6. Fitch WT. Rhythmic cognition in humans and animals: distinguishing meter and pulse perception. Front Syst Neurosci. 2013; 7: 68. https://doi.org/10.3389/fnsys.2013.00068 PMID: 24198765 7. Merchant H, Grahn J, Trainor L, Rohrmeier M, Fitch WT. Finding the beat: a neural perspective across humans and non-human primates. Philos Trans R Soc Lond B Biol Sci. 2015; 370(1664): 20140093. https://doi.org/10.1098/rstb.2014.0093 PMID: 25646516 8. Repp BH. Sensorimotor synchronization: A review of the tapping literature. Psychon Bull Rev. 2005; 12 (6): 969–992. https://doi.org/10.3758/BF03206433 PMID: 16615317 9. Repp BH, Su Y-H. Sensorimotor synchronization: A review of recent research (2006–2012). Psychon Bull Rev. 2013; 20(3): 403–452. https://doi.org/10.3758/s13423-012-0371-2 PMID: 23397235 10. Honing H, Merchant H, Ha´den GP, Prado L, Bartolo R. Rhesus Monkeys (Macaca mulatta) Detect Rhythmic Groups in Music, but Not the Beat. PLoS ONE. 2012; 7(12): e51369. https://doi.org/10.1371/ journal.pone.0051369 PMID: 23251509 PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 29 / 32 The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping 33. Shenoy K V, Sahani M, Churchland MM. Cortical control of arm movements: a dynamical systems per- spective. Annu Rev Neurosci. 2013; 36: 337–359. https://doi.org/10.1146/annurev-neuro-062111- 150509 PMID: 23725001 34. Remington ED, Narain D, Hosseini EA, Jazayeri M. Flexible Sensorimotor Computations through Rapid Reconfiguration of Cortical Dynamics. Neuron. 2018; 98(5): 1005–1019.e5. https://doi.org/10.1016/j. neuron.2018.05.020 PMID: 29879384 35. Mendoza G, Peyrache A, Ga´mez J, Prado L, Buzsa´ki G, Merchant H. Recording extracellular neural activity in the behaving monkey using a semichronic and high-density electrode system. J Neurophysiol. 2016; 116(2): 563–574. https://doi.org/10.1152/jn.00116.2016 PMID: 27169505 36. Hardy NF, Buonomano D V. Encoding Time in Feedforward Trajectories of a Recurrent Neural Network Model. Neural Comput. 2018; 30(2): 378–396. https://doi.org/10.1162/neco_a_01041 PMID: 29162002 37. Donnet S, Bartolo R, Fernandes JM, Cunha JPS, Prado L, Merchant H. Monkeys time their pauses of movement and not their movement-kinematics during a synchronization-continuation rhythmic task. J Neurophysiol. 2014; 111(10): 2138–2149. https://doi.org/10.1152/jn.00802.2013 PMID: 24572098 38. Goudar V, Buonomano D V. Encoding sensory and motor patterns as time-invariant trajectories in recurrent neural networks. Elife. 2018; 7: 1–28. https://doi.org/10.7554/eLife.31134 PMID: 29537963 39. Mendoza G, Merchant H. Motor system evolution and the emergence of high cognitive functions. Prog Neurobiol. 2014; 122: 73–93. https://doi.org/10.1016/j.pneurobio.2014.09.001 PMID: 25224031 40. Russo AA, Bittner SR, Perkins SM, Seely JS, London BM, Lara AH, et al. Motor Cortex Embeds Mus- cle-like Commands in an Untangled Population Response. Neuron. 2018; 97(4): 953—966.e8. https:// doi.org/10.1016/j.neuron.2018.01.004 PMID: 29398358 41. Churchland MM, Cunningham JP, Kaufman MT, Foster JD, Nuyujukian P, Ryu SI, et al. Neural popula- tion dynamics during reaching. Nature. 2012; 487(7405): 51–56. https://doi.org/10.1038/nature11129 PMID: 22722855 42. Karmarkar UR, Buonomano D V. Timing in the absence of clocks: encoding time in neural network states. Neuron. 2007; 53(3): 427–438. https://doi.org/10.1016/j.neuron.2007.01.006 PMID: 17270738 43. Merchant H, Yarrow K. How the motor system both encodes and influences our sense of time. Curr Opin Behav Sci. 2016; 8: 22–27. https://doi.org/10.1016/j.cobeha.2016.01.006 44. Paton JJ, Buonomano D V. The Neural Basis of Timing: Distributed Mechanisms for Diverse Functions. Neuron. 2018; 98(4): 687–705. https://doi.org/10.1016/j.neuron.2018.03.045 PMID: 29772201 45. Merchant H, Bartolo R, Pe´rez O, Me´ndez JC, Mendoza G, Ga´mez J, et al. Neurophysiology of Timing in the Hundreds of Milliseconds: Multiple Layers of Neuronal Clocks in the Medial Premotor Areas. Adv Exp Med Biol. 2014; 829: 143–154. https://doi.org/10.1007/978-1-4939-1782-2_8 PMID: 25358709 46. Teki S, Grube M, Griffiths T. PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 A Scalable Population Code for Time in the Striatum. Curr Biol. 2015; 25(9): 1113–1122. https://doi.org/10.1016/j.cub.2015.02.036 PMID: 25913405 24. Wang J, Narain D, Hosseini EA, Jazayeri M. Flexible timing by temporal scaling of cortical responses. Nat Neurosci. 2018; 21(1): 102–110. https://doi.org/10.1038/s41593-017-0028-6 PMID: 29203897 25. Merchant H, Zarco W, Pe´rez O, Prado L, Bartolo R. Measuring time with different neural chronometers during a synchronization-continuation task. Proc Natl Acad Sci U S A. 2011; 108(49): 19784–19789. https://doi.org/10.1073/pnas.1112933108 PMID: 22106292 26. Knudsen EB, Powers ME, Moxon KA. Dissociating Movement from Movement Timing in the Rat Pri- mary Motor Cortex. J Neurosci. 2014; 34(47): 15576–15586. https://doi.org/10.1523/JNEUROSCI. 1816-14.2014 PMID: 25411486 27. Jazayeri M, Shadlen MN. A Neural Mechanism for Sensing and Reproducing a Time Interval. Curr Biol. 2015; 25(20): 2599–2609. https://doi.org/10.1016/j.cub.2015.08.038 PMID: 26455307 28. Merchant H, Bartolo R. Primate beta oscillations and rhythmic behaviors. J Neural Transm. 2018; 125 (3): 461–470. https://doi.org/10.1007/s00702-017-1716-9 PMID: 28364174 29. Cunningham JP, Yu BM. Dimensionality reduction for large-scale neural recordings. Nat Neurosci. 2014; 17(11): 1500–1509. https://doi.org/10.1038/nn.3776 PMID: 25151264 30. Kobak D, Brendel W, Constantinidis C, Feierstein CE, Kepecs A, Mainen ZF, et al. Demixed principal component analysis of neural population data. Elife. 2016; 5: 1–36. https://doi.org/10.7554/eLife.10989 PMID: 27067378 31. Murray JM, Escola GS. Learning multiple variable-speed sequences in striatum via cortical tutoring. Elife. 2017; 6: 1–24. https://doi.org/10.7554/eLife.26084 PMID: 28481200 32. Rossi-Pool R, Zainos A, Alvarez M, Zizumbo J, Vergara J, Romo R. Decoding a Decision Process in the Neuronal Population of Dorsal Premotor Cortex. Neuron. 2017; 96(6): 1432—1446.e7. https://doi.org/ 10.1016/j.neuron.2017.11.023 PMID: 29224726 PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 30 / 32 The amplitude in periodic neural state trajectories underlies the tempo of rhythmic tapping 55. Chen JL, Penhune VB, Zatorre RJ. Moving on Time: Brain Network for Auditory-Motor Synchronization is Modulated by Rhythm Complexity and Musical Training. J Cogn Neurosci. 2008; 20(2): 226–239. https://doi.org/10.1162/jocn.2008.20018 PMID: 18275331 56. Grahn JA, Rowe JB. Feeling the Beat: Premotor and Striatal Interactions in Musicians and Nonmusi- cians during Beat Perception. J Neurosci. 2009; 29(23): 7540–7548. https://doi.org/10.1523/ JNEUROSCI.2018-08.2009 PMID: 19515922 57. Patel AD, Iversen JR. The evolutionary neuroscience of musical beat perception: the Action Simulation for Auditory Prediction (ASAP) hypothesis. Front Syst Neurosci. 2014; 8: 57. https://doi.org/10.3389/ fnsys.2014.00057 PMID: 24860439 58. Honing H, Merchant H. Differences in auditory timing between human and nonhuman primates. Behav Brain Sci. 2014; 37(6): 557–558. https://doi.org/10.1017/S0140525X13004056 PMID: 25514947 59. Cadena-Valencia J, Garcı´a-Garibay O, Merchant H, Jazayeri M, De Lafuente V. Entrainment and main- tenance of an internal metronome in supplementary motor area. Elife. 2018; 7. https://doi.org/10.7554/ eLife.38983 PMID: 30346275 60. Gibbon J, Malapani C, Dale CL, Gallistel CR. Toward a neurobiology of temporal cognition: Advances and challenges. Curr Opin Neurobiol. 1997; 7(2): 170–184. https://doi.org/10.1016/S0959-4388(97) 80005-0 PMID: 9142762 61. Merchant H, Zarco W, Prado L. Do we have a common mechanism for measuring time in the hundreds of millisecond range? Evidence from multiple-interval timing tasks. J Neurophysiol. 2008; 99(2): 939– 949. https://doi.org/10.1152/jn.01225.2007 PMID: 18094101 62. Garcı´a-Garibay O, Cadena-Valencia J, Merchant H, de Lafuente V. Monkeys Share the Human Ability to Internally Maintain a Temporal Rhythm. Front Psychol. 2016; 7: 1–12. https://doi.org/10.3389/fpsyg. 2016.01971 PMID: 28066294 63. Mendez JC, Prado L, Mendoza G, Merchant H. Temporal and Spatial Categorization in Human and Non-Human Primates. Front Integr Neurosci. 2011; 5: 1–10. https://doi.org/10.3389/fnint.2011.00050 PMID: 21927599 64. Simen P, Balci F, DeSouza L, Cohen JD, Holmes P. A Model of Interval Timing by Neural Integration. J Neurosci. 2011; 31(25): 9238–9253. https://doi.org/10.1523/JNEUROSCI.3121-10.2011 PMID: 21697374 65. Merchant H, Averbeck BB. The Computational and Neural Basis of Rhythmic Timing in Medial Premotor Cortex. J Neurosci. 2017; 37(17): 4552–4564. https://doi.org/10.1523/JNEUROSCI.0367-17.2017 PMID: 28336572 66. Pe´rez O, Merchant H. The synaptic properties of cells define the hallmarks of interval timing in a recur- rent neural network. J Neurosci. 2018; 38(17): 4186–4199. https://doi.org/10.1523/JNEUROSCI.2651- 17.2018 PMID: 29615484 67. Kaufman MT, Churchland MM, Ryu SI, Shenoy K V. Cortical activity in the null space: permitting prepa- ration without movement. Nat Neurosci. 2014; 17(3): 440–448. https://doi.org/10.1038/nn.3643 PMID: 24487233 68. Crowe DA, Averbeck BB, Chafee M V. PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 A Unified Model of Time Perception Accounts for Duration-Based and Beat-Based Timing Mechanisms. Front Integr Neurosci. 2012; 5: 90. https://doi.org/10.3389/fnint.2011. 00090 PMID: 22319477 47. Schwartze M, Kotz SA. A dual-pathway neural architecture for specific temporal prediction. Neurosci Biobehav Rev. 2013; 37(10 Pt 2): 2587–2596. https://doi.org/10.1016/j.neubiorev.2013.08.005 PMID: 23994272 48. Allman MJ, Teki S, Griffiths TD, Meck WH. Properties of the Internal Clock: First- and Second-Order Principles of Subjective Time. Annu Rev Psychol. 2014; 65: 743–771. https://doi.org/10.1146/annurev- psych-010213-115117 PMID: 24050187 49. Bartolo R, Merchant H. β Oscillations Are Linked to the Initiation of Sensory-Cued Movement Sequences and the Internal Guidance of Regular Tapping in the Monkey. J Neurosci. 2015; 35(11): 4635–4640. https://doi.org/10.1523/JNEUROSCI.4570-14.2015 PMID: 25788680 50. Jones MR, Boltz M. Dynamic attending and responses to time. Psychol Rev. 1989; 96(3): 459–491. PMID: 2756068 51. Large EW, Jones MR. The dynamics of attending: How people track time-varying events. Psychol Rev. 1999; 106(1): 119–159. https://doi.org/10.1037/0033-295X.106.1.119 52. Fujioka T, Trainor LJ, Large EW, Ross B. Internalized Timing of Isochronous Sounds Is Represented in Neuromagnetic Beta Oscillations. J Neurosci. 2012; 32(5): 1791–1802. https://doi.org/10.1523/ JNEUROSCI.4107-11.2012 PMID: 22302818 53. Iversen JR, Repp BH, Patel AD. Top-down control of rhythm perception modulates early auditory responses. Ann N Y Acad Sci. 2009; 1169: 58–73. https://doi.org/10.1111/j.1749-6632.2009.04579.x PMID: 19673755 54. Nozaradan S, Peretz I, Missal M, Mouraux A. Tagging the Neuronal Entrainment to Beat and Meter. J Neurosci. 2011; 31(28): 10234–10240. https://doi.org/10.1523/JNEUROSCI.0411-11.2011 PMID: 21753000 31 / 32 PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019 Rapid Sequences of Population Activity Patterns Dynamically Encode Task-Critical Spatial Information in Parietal Cortex. J Neurosci. 2010; 30(35): 11640–11653. https://doi.org/10.1523/JNEUROSCI.0954-10.2010 PMID: 20810885 69. Jin DZ, Fujii N, Graybiel AM. Neural representation of time in cortico-basal ganglia circuits. Proc Natl Acad Sci. 2009; 106(45): 19156–19161. https://doi.org/10.1073/pnas.0909881106 PMID: 19850874 70. Gouvêa TS, Monteiro T, Motiwala A, Soares S, Machens C, Paton JJ. Striatal dynamics explain dura- tion judgments. Elife. 2015; 4: 1–14. https://doi.org/10.7554/eLife.11386 PMID: 26641377 71. Pastalkova E, Itskov V, Amarasingham A, Buzsaki G. Internally Generated Cell Assembly Sequences in the Rat Hippocampus. Science. 2008; 321(5894): 1322–1327. https://doi.org/10.1126/science. 1159775 PMID: 18772431 72. MacDonald CJ, Lepage KQ, Eden UT, Eichenbaum H. Hippocampal “time cells” bridge the gap in mem- ory for discontiguous events. Neuron. 2011; 71(4): 737–749. https://doi.org/10.1016/j.neuron.2011.07. 012 PMID: 21867888 73. Perez O, Kass RE, Merchant H. Trial time warping to discriminate stimulus-related from movement- related neural activity. J Neurosci Methods. 2013; 212(2): 203–210. https://doi.org/10.1016/j.jneumeth. 2012.10.019 PMID: 23147009 74. Merchant H, Battaglia-mayer A, Georgopoulos AP. Effects of optic flow in motor cortex and area 7a. J Neurophysiol. 2001; 86(4): 1937–54. https://doi.org/10.1152/jn.2001.86.4.1937 PMID: 11600652 75. Waibel A, Hanazawa T, Hinton G, Shikano K, Lang KJ. Phoneme recognition using time-delay neural networks. IEEE Trans Acoust. 1989; 37(3): 328–339. https://doi.org/10.1109/29.21701 76. Cortes C, Vapnik V. Support-vector networks. Mach Learn. 1995; 20(3): 273–297. https://doi.org/10. 1007/BF00994018 32 / 32 PLOS Biology | https://doi.org/10.1371/journal.pbio.3000054 April 8, 2019
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Mitochondrial Function in Gilles de la Tourette Syndrome Patients With and Without Intragenic IMMP2L Deletions
Frontiers in neurology
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BRIEF RESEARCH REPORT published: 24 March 2020 doi: 10.3389/fneur.2020.00163 Mitochondrial Function in Gilles de la Tourette Syndrome Patients With and Without Intragenic IMMP2L Deletions Victoria A. Bjerregaard 1, Bitten Schönewolf-Greulich 1, Lene Juel Rasmussen 2, Claus Desler 2† and Zeynep Tümer 1,3*† 1 Department of Clinical Genetics, Kennedy Center, Copenhagen University Hospital, Rigshospitalet, Denmark, 2 Department of Cellular and Molecular Medicine, Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark, 3 Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark Background: Gilles de la Tourette syndrome (GTS) is a neurodevelopmental condition characterized by motor and vocal tics. The underlying etiology remains largely unknown, and GTS is considered as a complex multifactorial disorder associated with effects of several genes in combination with environmental factors. The inner mitochondrial membrane peptidase, subunit 2 (IMMP2L) has been suggested as one of the susceptibility genes for GTS, and IMMP2L-deficient mouse and human cells show increased levels of mitochondrial oxidative stress and altered cell fate programming. Hence, a potential involvement of IMMP2L-induced mitochondrial dysfunction in GTS pathology is yet to be elucidated. To address this, we investigated mitochondrial function in a group of GTS patients with intragenic IMMP2L deletions and compared with GTS without IMMP2L deletions and healthy controls. Edited by: Davide Martino, University of Calgary, Canada Reviewed by: Danielle Cath, University of Groningen, Netherlands Thomas V. Fernandez, Yale University, United States *Correspondence: Zeynep Tümer zeynep.tumer@regionh.dk †These authors share senior authorship Edited by: Davide Martino, University of Calgary, Canada Reviewed by: Danielle Cath, University of Groningen, Netherlands Thomas V. Fernandez, Yale University, United States *Correspondence: Zeynep Tümer zeynep.tumer@regionh.dk Methods: Mitochondrial function in fibroblasts from GTS patients and non-GTS parents (with and without IMMP2L deletions) compared to healthy controls were evaluated by measuring mitochondrial superoxide production, mitochondrial membrane potential, mitochondrial mass, and mitochondrial respiration. In addition, we evaluated apoptosis and senescence. Specialty section: This article was submitted to Movement Disorders, a section of the journal Frontiers in Neurology Specialty section: This article was submitted to Movement Disorders, a section of the journal Frontiers in Neurology Received: 21 October 2019 Accepted: 20 February 2020 Published: 24 March 2020 Results: None of the mitochondrial parameters assessed in this study were significantly distinctive when comparing GTS patients with and without IMMP2L deletions against healthy controls or parents with or without IMMP2L deletions, and we did not observe altered cell programming. Received: 21 October 2019 Accepted: 20 February 2020 Published: 24 March 2020 Conclusion: This study suggests that IMMP2L deletions do not lead to a substantial general mitochondrial dysfunction in GTS fibroblasts. Assessing a large cohort of controls and patients of similar age and gender would possibly reveal small differences in mitochondrial function. However, it is possible that IMMP2L variants affect mitochondrial function during specific instances of stress stimuli or in brain regions suggested to be affected in GTS. Keywords: Gilles de la Tourette syndrome, GTS, IMMP2L, mitochondria, oxidative stress Citation: Bjerregaard VA, Schönewolf-Greulich B, Juel Rasmussen L, Desler C and Tümer Z (2020) Mitochondrial Function in Gilles de la Tourette Syndrome Patients With and Without Intragenic IMMP2L Deletions. Front. Neurol. 11:163. doi: 10.3389/fneur.2020.00163 Keywords: Gilles de la Tourette syndrome, GTS, IMMP2L, mitochondria, oxidative stress March 2020 | Volume 11 | Article 163 Frontiers in Neurology | www.frontiersin.org 1 Mitochondrial Function in Gilles de la Tourette Syndrome Bjerregaard et al. INTRODUCTION (7). We hypothesized that impaired mitochondrial function through a defective cerebellar IMMP2L may contribute to GTS pathogenesis. To test this hypothesis, we conducted a series of mitochondrial studies in fibroblasts obtained from GTS patients with or without IMMP2L deletions compared to control fibroblasts obtained from parents without GTS and with or without deletions, and from asymptomatic controls. To our knowledge, this is the first study to evaluate mitochondrial function in fibroblasts from GTS patients. Gilles de la Tourette syndrome (GTS) is a neurodevelopmental disorder, characterized by sudden, repetitive, non-rhythmic movements or sounds, referred to as tics. The GTS diagnosis is based on several motor and at least one vocal tic that have persisted for more than a year. There is significant comorbidity between GTS and other neurobiological/neuropsychiatric conditions, especially attention deficit hyperactivity disorder (ADHD) and obsessive–compulsive disorder (OCD). The disease etiology is complex and multifactorial, with an evident genetic component (1). One of the suggested GTS susceptibility genes is the inner mitochondrial membrane peptidase, subunit 2 (IMMP2L) (2–7), and structural variants involving this gene are also implicated in other neurobiological/neuropsychiatric conditions including autism and ADHD (8–11). IMMP2L transcript is expressed in several brain regions including the cerebellum (7). Cerebellum is implied to have a role not only in motor function, but also in cognitive and emotional processes, and its dysfunction is implicated both in movement disorders (e.g., ataxia and dystonia) and non-motor neuropsychiatric diseases (e.g., autism and ADHD) (12). As mitochondrial dysfunction is also linked to disorders affecting cerebellum (13), IMMP2L is a plausible susceptibility factor for neurobiological/neuropsychiatric disorders including GTS. Subjects and Study Design j y g In this study, we analyzed skin fibroblasts available from four of our previously published GTS patients (P1, P2, P5, P6) and three non-GTS parents (of P1, P2, P6) with IMMP2L deletions (7). According to their own descriptions, the three parents had some behavioral features at subclinical level (Table 1). Three anonymous GTS patients and four non-GTS controls (including mothers of P1 and P6) without deletions were also included in the study. The following considerations were made for the inclusion of family members: (1) inclusion of two asymptomatic mothers without deletions (of P1 and P6) in the control group would ensure similar mitochondrial DNA background when comparing fibroblasts with and without IMMP2L deletions; (2) inclusion of the parents with a deletion and without a GTS diagnosis (of P1, P2, P6) would minimize the effect of the background variation in the nuclear genome on mitochondrial function, as half of the genetic material in the nuclear genome is identical between child–parent. g Studies in different organisms (yeast, mice, and human cells) show that substrates processed by IMMP2L include cytochrome c1, mitochondrial glycerol-3-phosphate dehydrogenase 2 (GPD- M), and apoptosis inducing factor (AIF) (14–16). Cytochrome c1 is involved in electron transfer in the mitochondrial electron transport chain, and GPD-M is a component of the mitochondrial glycerol phosphate shuttle, which functions in shuttling of electrons mitochondrial carriers in the oxidative phosphorylation pathway. Both peptides hence have important roles in mitochondrial respiratory chain and metabolism (17– 19). AIF triggers apoptosis and promotes removal of damaged and irreparable cells when activated by IMMP2L under oxidative stress, while in the absence of IMMP2L, cells are driven toward a senescent state (16). Thus, IMMP2L has an important role both in both mitochondrial metabolism and cell- fate determination. All the experiments investigating mitochondrial dysfunction were repeated at least three times. Quantitative visual scoring was performed blinded to avoid bias. Cell Cultures Fibroblasts were cultured in Dulbecco’s modified Eagle’s medium (DMEM) (Gibco) supplemented with 10% fetal bovine serum (FBS) (Gibco) and 1% penicillin/streptomycin, at 37◦C in a humidified atmosphere with 5% CO2. Cells were routinely tested for mycoplasma. Brain tissue from Immp2l mutant mice show increased production of reactive oxygen species (ROS), hyperpolarization, and increased levels of ATP, but seem to have a normal volume of mitochondria and bioenergetic capacity (15, 20). Phenotypically, Immp2l mutant mice display a series of features including altered behavior, reduced social interaction, early onset ataxia, and age-dependent degeneration of cerebellar granule neurons (21–25). The majority of these phenotypes has been proposed to be a consequence of cytotoxic insults caused by an increased superoxide production. Frontiers in Neurology | www.frontiersin.org Superoxide Generation Assay p y The level of mitochondrial ROS was quantified by measuring MitoSOX red (Molecular Probes, Invitrogen) using high- throughput microscopy (Nucleocounter 3000). Fibroblasts were incubated with 5 µM MitoSOX for 20 min at 37◦C and washed once in phosphate-buffered saline (PBS) before harvest. Cells were harvested, resuspended in 10 µg/ml Hoechst 33342 (Tocris), incubated for 10 min at 37◦C, and immediately analyzed. MitoSOX Red was excited at 530 nm, and data were collected at 675/75 nm. Hoechst was excited at 365 nm, and data were collected at 430/20 nm. Only live cells were included, and the mean fluorescence intensity (MFI) was obtained by subtracting the fluorescence of the control cells (not stained with MitoSOX) from the fluorescence of the MitoSOX stained cells. Our group has previously identified intragenic IMMP2L deletions in a Danish cohort of GTS patients, and these deletions had an occurrence that was significantly high compared to Danish controls (frequency, 3.7 vs. 0.9%, respectively) March 2020 | Volume 11 | Article 163 Frontiers in Neurology | www.frontiersin.org 2 Mitochondrial Function in Gilles de la Tourette Syndrome Bjerregaard et al. TABLE 1 | Subjects investigated in this study and information on fibroblast cultures. Superoxide Generation Assay Fibroblast Subject identification Sex Symptoms IMMP2L status (deleted exons)§ IMMP2L status effected transcript§ Age# Passage IMMP2L-1 P1 M GTS, ADHD Deletion (1a, 1b, 2, 3, 3a, 3b) Long/short 23 3 IMMP2L-2 P1 father M Dyslexia*, Temper* Deletion (1a, 1b, 2, 3, 3a, 3b) Long/short 52 2 IMMP2L-3 P2 M GTS, ADHD Deletion (2, 3) Long 20 3 IMMP2L-4 P2 mother F Tics*, OCD* Deletion (2, 3) Long 53 3 IMMP2L-5 P5 M GTS Deletion (3a, 3b) Short 23 2 IMMP2L-6 P6 M GTS, ADHD, OCD Deletion (3a, 3b) Short 19 2 IMMP2L-7 P6 father M Stubbornness* Deletion (3a, 3b) Short 62 3 TS-1 M GTS No deletion – 22 3 TS-2 M GTS No deletion – 24 3 TS-3 M GTS No deletion – 21 3 Control-1 P1 mother F No symptoms No deletion – 50 2 Control-2 P6 mother F No symptoms No deletion – 56 2 Control-3 104027 F No symptoms No deletion – 30 3 Control-4 104028 M No symptoms No deletion – 45 3 §IMMP2L has two alternative transcripts differing at the 5′-end: The long transcript has exons 1a, 1b, 2, 3, 5–7 (ATG start codon in exon2) and the short transcript has exons 3a, 3b, 5–7 (ATG start codon in exon 3a) (7). #Age (years) when biopsy was taken. *Subclinical symptoms according to individuals own description. GTS, Gilles de la Tourette syndrome; ADHD, attention deficit hyperactivity disorder; OCB, obsessive–compulsive behavior; OCD, obsessive–compulsive disorder; M, male; F, female. TABLE 1 | Subjects investigated in this study and information on fibroblast cultures. §IMMP2L has two alternative transcripts differing at the 5′-end: The long transcript has exons 1a, 1b, 2, 3, 5–7 (ATG start codon in exon2) and the short transcript has exons 3a, 3b, 5–7 (ATG start codon in exon 3a) (7). #Age (years) when biopsy was taken. *Subclinical symptoms according to individuals own description. GTS, Gilles de la Tourette syndrome; ADHD, attention deficit hyperactivity disorder; OCB, obsessive–compulsive behavior; OCD, obsessive–compulsive disorder; M, male; F, female. Mitochondrial Membrane Potential The mitochondrial membrane potential was determined by detecting tetramethylrhodamine, ethyl ester (TMRE) (Abcam) by high-throughput microscopy (Nucleocounter 3000). Fibroblasts were incubated with 100 nm TMRE for 15 min at 37◦C, briefly washed in PBS, and harvested by standard procedures. Cells were resuspended in 10 µg/ml Hoechst 33342 (Tocris), incubated 10 min at 37◦C, and immediately analyzed. TMRE was excited at 530 nm, and data were collected at 675/75 nm. Hoechst was excited at 365 nm, and data were collected at 430/20 nm. Only live cells were included in the MFI, and 20 µM carbonyl cyanide 4- (trifluoromethoxy) phenylhydrazone (FCCP) (Abcam) was used as a positive control. For each sample, a minimum of 5,000 cells were scored. The mitochondrial respiration was measured using an XF- 96 Extracellular Flux Analyzer (Seahorse Bioscience, Agilent). Seeded cells were washed and resuspended in Seahorse assay media (Seahorse Bioscience, Agilent), supplemented with 1 mM pyruvate, 2 mM glutamine, and adjusted to pH 7.4. Oxygen consumption rates (OCRs) were measured to establish a baseline. Subsequently, wells were injected with either 1 µM oligomycin, to measure ATP turnover from the changes in OCR, or with 0.5 µM carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (FCCP) to determine reserve respiratory capacity from change in OCR. All cells were finally treated with 2 µM antimycin A as a control. ATP Content and Mitochondrial Respiration Antimycin A (150 µM) (Sigma-Aldrich) was used as a positive control. For each sample, a minimum of 5,000 cells were scored. The ATP content was determined using the luciferase-based assay Vialight MDA Plus kit (Lonza) according to the manufacturer’s instructions. Levels of luminescence was quantified in a Microbeta2 scintillation counter (Perkin Elmer). DISCUSSION In this study, we investigated whether mitochondrial dysfunction was a contributing factor in disease etiology of GTS patients with and without deletions affecting the mitochondrial peptidase IMMP2L. Having the highest mitochondrial energy demand of all organs, the brain in particular is sensitive to mitochondrial dysfunction, which indeed has been implicated in the etiology of a wide spectrum of neurobiological and neuropsychiatric disorders (27, 28). IMMP2L has a dual role in the mitochondria affecting both the mitochondrial metabolism and the cell fate. IMMP2L deficiency has been linked to mitochondrial dysfunction in the form of increased oxidative stress, a pathological feature common to several central nervous system disorders (29), and increased occurrence of cellular senescence, a pathological feature of neurodegeneration (30). In line with this, rare structural variants affecting IMMP2L were implicated as susceptibility factors in autism spectrum disorders (31) and ADHD (11). To determine the level of mitochondrial ROS, we measured mitochondrial levels of superoxide, which represents total mitochondrial ROS, using mitoSOX in living and unstressed fibroblasts. In cells from all subjects, the level of ROS was below that of the stressed positive control (antimycin A), and we did not observe any significant differences between each subject or between the IMMP2L deletion, GTS-without deletion, or control group (Figure 1A). The results did not change when the non-GTS parents with or without IMMP2L deletions were omitted from the analysis (statistical analysis not included, raw data available). Mitochondrial membrane potential was measured using the fluorophore TMRE that labels mitochondria proportional to the potential across the inner membrane. Depolarized or inactive mitochondria fail to sequester TMRE. The membrane potential of mitochondria is related to its ability to produce ATP by oxidative phosphorylation, but it is also an indicator of general apoptosis, as collapse of the mitochondrial membrane triggers an apoptotic cascade. No significant difference in mitochondrial membrane potential was demonstrated between fibroblasts of individual patients or between the three groups (Figure 1B). p IMMP2L has been suggested as a candidate susceptibility gene in GTS (3, 6), and we have shown that intragenic IMMP2L deletions were present at a higher frequency in GTS patients compared to control population. We hypothesized that the IMMP2L deletions could exert their effect through impaired mitochondrial function (7). Apoptosis and Senescence The mitochondrial mass of active mitochondria was quantified by measuring MitoTracker Green probe (Molecular Probes, Invitrogen) by high-throughput microscopy (Nucleocounter 3000). Cells were incubated with 100 nM MitoTracker for 20 min at 37◦C and washed once in PBS before harvest. Cells were resuspended in 10 µg/ml Hoechst 33342 (Tocris), incubated 10 min at 37◦C, and immediately analyzed. MitoTracker Green was excited at 475 nm, and data were collected in the 560/35 nm channel. Hoechst was excited at 365 nm, and data were collected in the 430/20 nm channel. Only live cells were included. For each sample, a minimum of 5,000 cells were scored. The apoptotic state of the fibroblasts was evaluated using the Annexin V-CF488A conjugate (Biotium) following the instructions of the Nucleocounter NC-3000 Annexin V Assay (Application note no. 3017 Rev. 1.4). For each sample, a minimum of 5,000 cells were scored. Senescence was analyzed using the SA-β-Gal-based senescence detection kit (Abcam) according to the manufacturer’s instructions. The percentage of senescent cells were scored after five passages using the EVOS XL Core Cell Imaging System (Life Technologies) and the cell counter plugin March 2020 | Volume 11 | Article 163 Frontiers in Neurology | www.frontiersin.org 3 Mitochondrial Function in Gilles de la Tourette Syndrome Bjerregaard et al. ImageJ software (NIH). A minimum of 200 cells were counted per sample per experimental replica. ImageJ software (NIH). A minimum of 200 cells were counted per sample per experimental replica. between fibroblasts of individual patients or between different groups as described above. To evaluate cell fate of the fibroblasts, we quantified the percentage of cells in apoptosis and senescence. Live apoptotic cells were stained with the apoptotic marker Annexin V and distinguished from dead cells by propidium iodine. The percentage of apoptotic cells were within a normal range for all fibroblasts, and we did not observe any differences between individuals or when comparing the two groups of GTS patients with controls (Figure 3A). To determine the percentage of cells in senescence, cells were fixed and stained with β-Gal in their exponential phase. Since the number of cells in senescence increases with age (26), individuals over 50 years of age were excluded from this assay (see Table 1). No significant difference was observed between individuals or between different groups as described above (Figure 3C). RESULTS The subjects investigated in this study were divided into three groups: (1) seven individuals with IMMP2L deletions (IMMP2L1–7), where four of them were clinically diagnosed with GTS (P1, P2, P5, and P6) and three of them were parents (of P1, P2, and P6) without a GTS diagnosis; (2) three GTS patients without IMMP2L deletions (TS 1–3); and (3) four controls without any GTS symptoms (control 1–4) including mothers of patients P1 and P6 (Table 1). The subjects investigated in this study were divided into three groups: (1) seven individuals with IMMP2L deletions (IMMP2L1–7), where four of them were clinically diagnosed with GTS (P1, P2, P5, and P6) and three of them were parents (of P1, P2, and P6) without a GTS diagnosis; (2) three GTS patients without IMMP2L deletions (TS 1–3); and (3) four controls without any GTS symptoms (control 1–4) including mothers of patients P1 and P6 (Table 1). Statistics Results are presented as mean ± SD from at least three experimental replicas. A one-way analysis of variance (ANOVA) and Tukey tests were used to compare subjects individually or as specified groups (Table 1). A p < 0.05 was considered significant. All statistical analyses were carried out using Prism software (Graphpad). Frontiers in Neurology | www.frontiersin.org DISCUSSION To test this hypothesis, we conducted a series of experiments to assess whether fibroblasts from GTS patients with or without IMMP2L deletions would show phenotypes of oxidative stress or other signs of mitochondrial dysfunction compared to controls. As control individuals, we also included parents without GTS and with IMMP2L deletions, to ensure a more similar background for the nuclear genome to minimize any confounding effect of background variations, and asymptomatic mothers without deletions and to ensure a similar mitochondrial DNA background (Table 1). This would be an important issue in case we found a difference in mitochondrial function. However, we found no evidence for altered mitochondrial ROS, membrane potential, mass, respiration, or ATP content, suggesting that there is no substantial mitochondrial dysfunction in fibroblasts of GTS patients with or without IMMP2L deletions. However, these Determination of mitochondrial mass provides a simplified overview of mitochondrial dynamics and is one of the signs of an altered activity of mitochondrial fission, fusion, biogenesis, or mitophagy. To label mitochondria in live cells, we used a MitoTracker probe, which passively diffuses across the plasma membrane and accumulates in active mitochondria. We did not observe significant difference in mitochondrial mass between individual subjects or between the three groups (Figure 1C). To evaluate the bioenergetic capacity, we quantified basal respiration rate, ATP turnover, and reserve respiratory in live cells by standard protocols using the Seahorse XF analyzer (Figures 2A–D), and for a total overview of the energy metabolism, whole-cell count of ATP was determined (Figure 2E). None of the assays showed a significant difference March 2020 | Volume 11 | Article 163 Frontiers in Neurology | www.frontiersin.org 4 Mitochondrial Function in Gilles de la Tourette Syndrome Bjerregaard et al. y RE 1 | Fibroblasts of Gilles de la Tourette syndrome (GTS) patients with and without IMMP2L deletions display no signs of oxidative stress, altered membrane tial, or abnormal mitochondrial mass. (A) Mitochondrial reactive oxygen species (ROS) levels presented as relative MitoSOX MFI ± SD of each subject (left) and h group (right). (B) Mitochondrial membrane potential presented as relative TMRE MFI ± SD of each subject (left) and of each group (right). (C) Mitochondrial presented as MitoTracker MFI ± SD of each subject (left) and of each group (right). All MFI values are normalized to the mean of the healthy control cells within experimental replica. Each bar represents at least three independent experiments. DISCUSSION Black stars mark non-GTS individuals with IMMP2L deletions. gs do not exclude that processing of known IMMP2L ates, such as cytochrome c1, GPD-M, and AIF is affected, IMMP2L has a key role in cell-fate programming during conditions of increased ROS by either promoting apoptosis FIGURE 1 | Fibroblasts of Gilles de la Tourette syndrome (GTS) patients with and without IMMP2L deletions display no signs of oxidative stress, altered membrane potential, or abnormal mitochondrial mass. (A) Mitochondrial reactive oxygen species (ROS) levels presented as relative MitoSOX MFI ± SD of each subject (left) and of each group (right). (B) Mitochondrial membrane potential presented as relative TMRE MFI ± SD of each subject (left) and of each group (right). (C) Mitochondrial mass presented as MitoTracker MFI ± SD of each subject (left) and of each group (right). All MFI values are normalized to the mean of the healthy control cells within each experimental replica. Each bar represents at least three independent experiments. Black stars mark non-GTS individuals with IMMP2L deletions. IMMP2L has a key role in cell-fate programming during conditions of increased ROS by either promoting apoptosis by AIF activation or being shut down upon the onset of IMMP2L has a key role in cell-fate programming during conditions of increased ROS by either promoting apoptosis by AIF activation or being shut down upon the onset of findings do not exclude that processing of known IMMP2L substrates, such as cytochrome c1, GPD-M, and AIF is affected, and further studies are necessary to clarify this. March 2020 | Volume 11 | Article 163 Frontiers in Neurology | www.frontiersin.org 5 Mitochondrial Function in Gilles de la Tourette Syndrome Bjerregaard et al. E 2 | Properties of mitochondrial respiration were unaltered in fibroblasts of Gilles de la Tourette syndrome (GTS) patients with and without IMMP2L deletions. spiration overview of groups. (B) Basal respiration as determined as initial resting consumption of oxygen. (C) ATP turnover as measured as a decrease in consumption after addition of oligomycin. (D) Reserve respiratory capacity as measured as a percentage of basal respiration, after addition of FCCP. The y between the groups was also present in whole-cell ATP levels. (E) Mean percentage ± SD of whole-cell ATP presented for each subject (left) and the three (right). Black stars mark non-GTS individuals with IMMP2L deletions. DISCUSSION All values are normalized to the mean of the healthy control cells within each experimental Each bar represents at least three independent experiments. FIGURE 2 | Properties of mitochondrial respiration were unaltered in fibroblasts of Gilles de la Tourette syndrome (GTS) patients with and without IMMP2L deletions. (A) Respiration overview of groups. (B) Basal respiration as determined as initial resting consumption of oxygen. (C) ATP turnover as measured as a decrease in oxygen consumption after addition of oligomycin. (D) Reserve respiratory capacity as measured as a percentage of basal respiration, after addition of FCCP. The similarity between the groups was also present in whole-cell ATP levels. (E) Mean percentage ± SD of whole-cell ATP presented for each subject (left) and the three groups (right). Black stars mark non-GTS individuals with IMMP2L deletions. All values are normalized to the mean of the healthy control cells within each experimental replica. Each bar represents at least three independent experiments. March 2020 | Volume 11 | Article 163 6 Frontiers in Neurology | www.frontiersin.org Mitochondrial Function in Gilles de la Tourette Syndrome Bjerregaard et al. Gilles de la Tourette syndrome (GTS) patients with and without IMMP2L deletions show no signs of increased apoptosis or senescence (A) Mean FIGURE 3 | Gilles de la Tourette syndrome (GTS) patients with and without IMMP2L deletions show no signs of increased apoptosis or senescence. (A) Mean percentage ± SD of apoptotic cells presented for each subject (left) and the three groups (right). (B) Representatives of dot plot and histogram for Annexin V and propidium iodine (PI) staining. As indicated on the dot plot, the cell population was divided into apoptotic, late apoptotic/dead, and dead. The apoptotic population was included in the charts. Black stars mark non-GTS individuals with IMMP2L deletions. (C) Mean percentage ± SD of senescent cells presented for each subject (left) and the three groups (right). (D) Representative image of a fibroblast culture with a senescent cell positive for β-Gal (arrow). For all charts, each bar represents three independent experiments. n indicates the number of cells analyzed per replica. FIGURE 3 | Gilles de la Tourette syndrome (GTS) patients with and without IMMP2L deletions show no signs of increased apoptosis or senescence. (A) Mean percentage ± SD of apoptotic cells presented for each subject (left) and the three groups (right). (B) Representatives of dot plot and histogram for Annexin V and propidium iodine (PI) staining. REFERENCES 8. Leblond CS, Cliquet F, Carton C, Huguet G, Mathieu A, Kergrohen T, et al. Both rare and common genetic variants contribute to autism in the Faroe Islands. NPJ Genom Med. (2019) 4:1. doi: 10.1038/s41525-018-0075-2 1. Robertson MM, Eapen V, Singer HS, Martino D, Scharf JM, Paschou P, et al. Gilles de la Tourette syndrome. Nat Rev Dis Primers. (2017) 3:16097. doi: 10.1038/nrdp.2016.97 1. Robertson MM, Eapen V, Singer HS, Martino D, Scharf JM, Paschou P, et al. Gilles de la Tourette syndrome. Nat Rev Dis Primers. (2017) 3:16097. doi: 10.1038/nrdp.2016.97 9. Baldan F, Gnan C, Franzoni A, Ferino L, Allegri L, Passon N, et al. Genomic deletion involving the IMMP2L gene in two cases of autism spectrum disorder. Cytogenet Genome Res. (2018) 154:196–200. doi: 10.1159/000489001 2. Boghosian-Sell L, Comings DE, Overhauser J. Tourette syndrome in a pedigree with a 7;18 translocation: identification of a YAC spanning the translocation breakpoint at 18q22.3. Am J Hum Genet. (1996) 59:999–1005. 2. Boghosian-Sell L, Comings DE, Overhauser J. Tourette syndrome in a pedigree with a 7;18 translocation: identification of a YAC spanning the translocation breakpoint at 18q22.3. Am J Hum Genet. (1996) 59:999–1005. 10. Viñas-Jornet M, Esteba-Castillo S, Baena N, Ribas-Vidal N, Ruiz A, Torrents- Rodas D, et al. High incidence of copy number variants in adults with intellectual disability and co-morbid psychiatric disorders. Behav Genet. (2018) 48:323–36. doi: 10.1007/s10519-018-9902-6 3. Petek E, Windpassinger C, Vincent JB, Cheung J, Boright AP, Scherer SW, et al. Disruption of a novel gene (IMMP2L) by a breakpoint in 7q31 associated with Tourette syndrome. Am J Hum Genet. (2001) 68:848–58. doi: 10.1086/319523 3. Petek E, Windpassinger C, Vincent JB, Cheung J, Boright AP, Scherer SW, et al. Disruption of a novel gene (IMMP2L) by a breakpoint in 7q31 associated with Tourette syndrome. Am J Hum Genet. (2001) 68:848–58. doi: 10.1086/319523 11. Elia J, Gai X, Xie HM, Perin JC, Geiger E, Glessner JT, et al. Rare structural variants found in attention-deficit hyperactivity disorder are preferentially associated with neurodevelopmental genes. Mol Psychiatry. (2010) 15:637– 46. doi: 10.1038/mp.2009.57 4. Kroisel PM, Petek E, Emberger W, Windpassinger C, Wladika W, Wagner K. Candidate region for Gilles de la Tourette syndrome at 7q31. Am J Med Genet. (2001) 101:259–61. doi: 10.1002/1096-8628(20010701)101:3<259:: AID-AJMG1374>3.0.CO;2-%23 4. Kroisel PM, Petek E, Emberger W, Windpassinger C, Wladika W, Wagner K. Candidate region for Gilles de la Tourette syndrome at 7q31. Am J Med Genet. (2001) 101:259–61. DISCUSSION As indicated on the dot plot, the cell population was divided into apoptotic, late apoptotic/dead, and dead. The apoptotic population was included in the charts. Black stars mark non-GTS individuals with IMMP2L deletions. (C) Mean percentage ± SD of senescent cells presented for each subject (left) and the three groups (right). (D) Representative image of a fibroblast culture with a senescent cell positive for β-Gal (arrow). For all charts, each bar represents three independent experiments. n indicates the number of cells analyzed per replica. FIGURE 3 | Gilles de la Tourette syndrome (GTS) patients with and without IMMP2L deletions show no signs of increased apoptosis or senescence. (A) Mean percentage ± SD of apoptotic cells presented for each subject (left) and the three groups (right). (B) Representatives of dot plot and histogram for Annexin V and propidium iodine (PI) staining. As indicated on the dot plot, the cell population was divided into apoptotic, late apoptotic/dead, and dead. The apoptotic population was included in the charts. Black stars mark non-GTS individuals with IMMP2L deletions. (C) Mean percentage ± SD of senescent cells presented for each subject (left) and the three groups (right). (D) Representative image of a fibroblast culture with a senescent cell positive for β-Gal (arrow). For all charts, each bar represents three independent experiments. n indicates the number of cells analyzed per replica. March 2020 | Volume 11 | Article 163 7 Frontiers in Neurology | www.frontiersin.org Bjerregaard et al. Mitochondrial Function in Gilles de la Tourette Syndrome ACKNOWLEDGMENTS We thank all the families for their participation and contribution to this work. ETHICS STATEMENT This study was approved by the Danish Regional Committee on Health Research Ethics (H-1-2014-109). All included participants gave their specific consent to participate and for the publication of the data. Cerebellum has been implicated in GTS pathophysiology (32, 33), and our group has previously shown that IMMP2L transcripts were highly expressed in the granular and Purkinje cell layer of the cerebellum (7). Abnormal or dysfunctional cerebellum and Purkinje cells have also been implicated in other neurodevelopmental and movement disorders, such as autism spectrum disorders, ataxia, and dystonia, and notably, mitochondrial dysfunction is linked to these disorders (34– 36). It is thus possible that IMMP2L deletions have a more pronounced effect in high energy-dependent neurons, such as the Purkinje cells, which are known to be vulnerable to mitochondrial dysfunction (36). Notably, Purkinje cells are a class of GABAergic (γ-aminobutyric acid) neurons, and altered GABA function has been suggested to contribute to GTS pathology (37). Further studies using induced pluripotent stem cell (iPSC)-derived brain cells, including GABAergic neurons, are necessary to understand the involvement of mitochondrial dysfunction in brain tissues. FUNDING This study was supported by the Lundbeck Foundation (R100- 2001-933). LJ was supported by Nordea-fonden and Olav Thon Stiftelsen. CD was supported by Nordea-fonden. This study was supported by the Lundbeck Foundation (R100- 2001-933). LJ was supported by Nordea-fonden and Olav Thon Stiftelsen. CD was supported by Nordea-fonden. In summary, we could not show a substantial mitochondrial dysfunction in GTS patients with or without IMMP2L deletions in fibroblast. However, involvement of IMMP2L in GTS pathogenesis cannot be completely excluded, and further studies investigating larger number of patients and using iPSC-derived neuronal cells are necessary. AUTHOR CONTRIBUTIONS VB designed and carried out the experiments presented in Figures 1, 3. CD designed and conducted the experiments presented in Figure 2, with assistance from VB. BS-G collected the skin biopsies from patients. VB and CD performed the data analysis and interpretation. ZT conceptualized the project and guided the experimental design. LJ contributed with equipment and reagents. The manuscript was written by VB and ZT with the contribution of CD. DATA AVAILABILITY STATEMENT senescence (16). In GTS fibroblasts, we did not observe induction of either apoptosis or senescence, but this could be due to the normal ROS levels that we have measured. It is therefore plausible that in high ROS levels, a defective IMMP2L may not be able to process AIF to its proapoptotic active form. Further studies may elucidate how fibroblasts with IMMP2L deletions would respond to exogenous stimulation of ROS. All datasets generated for this study are included in the article/supplementary material. REFERENCES doi: 10.1002/1096-8628(20010701)101:3<259:: AID-AJMG1374>3.0.CO;2-%23 12. Phillips JR, Hewedi DH, Eissa AM, Moustafa AA. The cerebellum and psychiatric disorders. Front Public Health. (2015) 3:66. doi: 10.3389/fpubh.2015.00066 5. Díaz-Anzaldúa A, Joober R, Rivière JB, Dion Y, Lespérance P, Chouinard S, et al. Association between 7q31 markers and Tourette syndrome. Am J Med Genet A. (2004) 127A:17–20. doi: 10.1002/ajmg.a.20631 5. Díaz-Anzaldúa A, Joober R, Rivière JB, Dion Y, Lespérance P, Chouinard S, et al. Association between 7q31 markers and Tourette syndrome. Am J Med Genet A. (2004) 127A:17–20. doi: 10.1002/ajmg.a.20631 13. Ward JM, Stoyas CA, Switonski PM, Ichou F, Fan W, Collins B, et al. Metabolic and organelle morphology defects in mice and human patients define spinocerebellar ataxia type 7 as a mitochondrial disease. Cell Rep. (2019) 26:1189–202.e6. doi: 10.1016/j.celrep.2019.01.028 6. Patel C, Cooper-Charles L, McMullan DJ, Walker JM, Davison V, Morton J. Translocation breakpoint at 7q31 associated with tics: further evidence for IMMP2L as a candidate gene for Tourette syndrome. Eur J Hum Genet. (2011) 19:634–9. doi: 10.1038/ejhg.2010.238 14. Luo W, Fang H, Green N. Substrate specificity of inner membrane peptidase in yeast mitochondria. Mol Genet Genomics. (2006) 275:431– 6. doi: 10.1007/s00438-006-0099-7 7. Bertelsen B, Melchior L, Jensen LR, Groth C, Glenthøj B, Rizzo R, et al. Intragenic deletions affecting two alternative transcripts of the IMMP2L gene in patients with Tourette syndrome. Eur J Hum Genet. (2014) 22:1283– 9. doi: 10.1038/ejhg.2014.24 7. Bertelsen B, Melchior L, Jensen LR, Groth C, Glenthøj B, Rizzo R, et al. Intragenic deletions affecting two alternative transcripts of the IMMP2L gene in patients with Tourette syndrome. Eur J Hum Genet. (2014) 22:1283– 9. doi: 10.1038/ejhg.2014.24 15. Lu B, Poirier C, Gaspar T, Gratzke C, Harrison W, Busija D, et al. A mutation in the inner mitochondrial membrane peptidase 2-like gene (Immp2l) affects March 2020 | Volume 11 | Article 163 Frontiers in Neurology | www.frontiersin.org 8 Mitochondrial Function in Gilles de la Tourette Syndrome Bjerregaard et al. mitochondrial function and impairs fertility in mice. Biol Reprod. (2008) 78:601–10. doi: 10.1095/biolreprod.107.065987 mitochondrial function and impairs fertility in mice. Biol Reprod. (2008) 78:601–10. doi: 10.1095/biolreprod.107.065987 28. Pei L, Wallace DC. Mitochondrial etiology of neuropsychiatric disorders. Biol Psychiatry. (2018) 83:722–30. doi: 10.1016/j.biopsych.2017.11.018 y y j y 29. Patel M. Targeting oxidative stress in central nervous system disorders. Trends Pharmacol Sci. (2016) 37:768–78. doi: 10.1016/j.tips.2016.06.007 16. Yuan L, Zhai L, Qian L, Huang D, Ding Y, Xiang H, et al. REFERENCES Switching offIMMP2L signaling drives senescence via simultaneous metabolic alteration and blockage of cell death. Cell Res. (2018) 28:625–43. doi: 10.1038/s41422-018-0043-5 30. Kritsilis M, V Rizou S, Koutsoudaki PN, Evangelou K, Gorgoulis VG, Papadopoulos D. Ageing, cellular senescence and neurodegenerative disease. Int J Mol Sci. (2018) 19:E2937. doi: 10.3390/ijms19102937 17. Hunte C, Palsdottir H, Trumpower BL. Protonmotive pathways and mechanisms in the cytochrome bc1 complex. FEBS Lett. (2003) 545:39– 46. doi: 10.1016/s0014-5793(03)00391-0 31. Maestrini E, Pagnamenta AT, Lamb JA, Bacchelli E, Sykes NH, Sousa I, et al. High-density SNP association study and copy number variation analysis of the AUTS1 and AUTS5 loci implicate the IMMP2L–DOCK4 gene region in autism susceptibility. Mol Psychiatry. (2010) 15:954– 68. doi: 10.1038/mp.2009.34 18. Lee YJ, Jeschke GR, Roelants FM, Thorner J, Turk BE. Reciprocal phosphorylation of yeast glycerol-3-phosphate dehydrogenases in adaptation to distinct types of stress. Mol Cell Biol. (2012) 32:4705–17. doi: 10.1128/MCB.00897-12 32. Bohlhalter S, Goldfine A, Matteson S, Garraux G, Hanakawa T, Kansaku K, et al. Neural correlates of tic generation in Tourette syndrome: an event-related functional MRI study. Brain. (2006) 129:2029–37. doi: 10.1093/brain/awl050 19. Vance JE. Phospholipid synthesis and transport in mammalian cells. Traffic. (2015) 16:1–18. doi: 10.1111/tra.12230 20. Bharadwaj MS, Zhou Y, Molina AJ, Criswell T, Lu B. Examination of bioenergetic function in the inner mitochondrial membrane peptidase 2-like (Immp2l) mutant mice. Redox Biol. (2014) 2:1008–15. doi: 10.1016/j.redox.2014.08.006 33. Tobe RH, Bansal R, Xu D, Hao X, Liu J, Sanchez J, et al. Cerebellar morphology in Tourette syndrome and obsessive-compulsive disorder. Ann Neurol. (2010) 67:479–87. doi: 10.1002/ana.21918 21. Soler R, Füllhase C, Lu B, Bishop CE, Andersson KE. Bladder dysfunction in a new mutant mouse model with increased superoxide–lack of nitric oxide? J Urol. (2010) 183:780–5. doi: 10.1016/j.juro.2009.09.074 34. Hollis F, Kanellopoulos AK, Bagni C. Mitochondrial dysfunction in Autism Spectrum Disorder: clinical features and perspectives. Curr Opin Neurobiol. (2017) 45:178–87. doi: 10.1016/j.conb.2017.05.018 22. George SK, Jiao Y, Bishop CE, Lu B. Mitochondrial peptidase IMMP2L mutation causes early onset of age-associated disorders and impairs adult stem cell self-renewal. Aging Cell. (2011) 10:584–94. doi: 10.1111/j.1474-9726.2011.00686.x 35. Flønes IH, Tzoulis C. Movement disorders in mitochondrial disease: a clinicopathological correlation. Curr Opin Neurol. (2018) 31:472– 83. doi: 10.1097/WCO.0000000000000583 36. Ghaoui R, Sue CM. Movement disorders in mitochondrial disease. J Neurol. (2018) 265:1230–40. doi: 10.1007/s00415-017-8722-6 36. Ghaoui R, Sue CM. Movement disorders in mitochondrial disease. J Neurol. (2018) 265:1230–40. doi: 10.1007/s00415-017-8722-6 23. Frontiers in Neurology | www.frontiersin.org REFERENCES George SK, Jiao Y, Bishop CE, Lu B. Oxidative stress is involved in age- dependent spermatogenic damage of Immp2l mutant mice. Free Radic Biol Med. (2012) 52:2223–33. doi: 10.1016/j.freeradbiomed.2012.04.003 37. Jackson GM, Draper A, Dyke K, Pépés SE, Jackson SR. Inhibition, disinhibition, and the control of action in Tourette syndrome. Trends Cogn Sci. (2015) 19:655–65. doi: 10.1016/j.tics.2015.08.006 37. Jackson GM, Draper A, Dyke K, Pépés SE, Jackson SR. Inhibition, disinhibition, and the control of action in Tourette syndrome. Trends Cogn Sci. (2015) 19:655–65. doi: 10.1016/j.tics.2015.08.006 24. Liu C, Li X, Lu B. The Immp2l mutation causes age-dependent degeneration of cerebellar granule neurons prevented by antioxidant treatment. Aging Cell. (2016) 15:167–76. doi: 10.1111/acel.12426 Conflict of Interest: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. 25. Kreilaus F, Chesworth R, Eapen V, Clarke R, Karl T. First behavioural assessment of a novel Immp2l knockdown mouse model with relevance for Gilles de la Tourette syndrome and Autism spectrum disorder. Behav Brain Res. (2019) 374:112057. doi: 10.1016/j.bbr.2019. 112057 Copyright © 2020 Bjerregaard, Schönewolf-Greulich, Juel Rasmussen, Desler and Tümer. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. 26. Herbig U, Ferreira M, Condel L, Carey D, Sedivy JM. Cellular senescence in aging primates. Science. (2006) 311:1257. doi: 10.1126/science.1122446 27. Rezin GT, Amboni G, Zugno AI, Quevedo J, Streck EL. Mitochondrial dysfunction and psychiatric disorders. Neurochem Res. (2009) 34:1021– 9. doi: 10.1007/s11064-008-9865-8 March 2020 | Volume 11 | Article 163 Frontiers in Neurology | www.frontiersin.org 9
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Acoustic Intervention in a Cultural Heritage: The Chapel of the Royal Palace in Caserta, Italy
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Acoustic Intervention in a Cultural Heritage: The Chapel of the Royal Palace in Caserta, Italy Umberto Berardi 1,†, Gino Iannace 2,*,† and Carmine Ianniello 3,† 1 Department of Architectural Science, Ryerson University, Toronto, ON M5B 2K3, Canada; uberardi@ryerson.ca 1 Department of Architectural Science, Ryerson University, Toronto, ON M5B 2K3, Canada; uberardi@ryerson.ca 2 Dipartimento di Architettura e Disegno Industriale, Seconda Università di Napoli, Aversa 81031, Italy 3 Dipartimento di Ingegneria Industriale, Università di Napoli “Federico II”, Napoli 80125, Italy; ianniell@unina2.it 2 Dipartimento di Architettura e Disegno Industriale, Seconda Università di Napoli, Aversa 81031, Italy 3 Dipartimento di Ingegneria Industriale, Università di Napoli “Federico II”, Napoli 80125, Italy; ianniell@unina2.it * Correspondence: gino.iannace@unina2.it; Tel.: +39-081-5010845; Fax: +39-081-8149266 h h b d ll h k * Correspondence: gino.iannace@unina2.it; Tel.: +39-081-5010845; Fax: +39-081-8149266 † These authors contributed equally to this work. * Correspondence: gino.iannace@unina2.it; Tel.: +39-081-5010845; Fax: +39-081-8149266 † These authors contributed equally to this work. Correspondence: gino.iannace@unina2.it; Tel.: +39-081-5010845; Fax: +39-081-8149266 † These authors contributed equally to this work. † These authors contributed equally to this work. † These authors contributed equally to this work. Abstract: The modern use of ancient heritage sites can be, to say the least, challenging from an acoustical perspective. In fact, modern needs may require acoustical interventions in contrast with the preservation issues of the cultural heritage. This paper deals with this topic in an UNESCO designated world heritage site, the Palatine Chapel of the Royal Palace in Caserta, Italy. Since this chapel is currently being used for meetings and music chamber concerts, the acoustical characteristics of the chapel, originally used for religious purposes, are investigated. Field measurements were undertaken to evaluate the acoustical performance of the empty chapel. The measurements were then used to calibrate and validate a computer simulation model. Different acoustical treatments are then considered and simulations are used to determine the related acoustical improvements. Finally, the benefits of different acoustical treatments which are respectful of the aesthetic and historical value of this cultural heritage are discussed. Keywords: room acoustics; cultural heritage; reverberation; simulations; sound absorption panels Keywords: room acoustics; cultural heritage; reverberation; simulations; sound absorption pane Buildings 2016, 6, 1; doi:10.3390/buildings6010001 1. Introduction Italy, one of the cradles of Western Civilization, has over 100,000 monuments such as churches, cathedrals, archaeological sites, and historical palaces, and it has the most United Nations Educational, Scientific and Cultural Organization (UNESCO) designated world heritage sites [1]. Among the 51 sites on the list there is the 18th-Century Royal Palace at Caserta with its park, the Aqueduct of Vanvitelli, and the San Leucio Complex. This large scale palace was created by the Bourbon King of Naples Charles III as the Italian response to the Palace of Versailles or the Royal Palace in Madrid [2]. The building exemplifies the Italian way of bringing together a magnificent palace with its park and gardens, as well as natural woodland, hunting lodges, and a silk factory. In fact, the site expresses the beauty of the integration of the architectural masterpiece into the natural landscape. The Palace, designed and built by the architect Luigi Vanvitelli, was the Bourbon dynasty’s way to showcase the Kingdom of the Two Sicilies [2]. The Palatine Chapel, the focus of the current study, is located within the Royal Palace and was opened with a midnight mass on Christmas day, 1784 in the presence of King Ferdinand IV. The chapel emulates the analogous room of the Palace of Versailles. Originally dedicated to religious purposes, the magnificent chapel, located on the first floor of the Palace (Figure 1), is currently used for public events such as meetings and chamber music concerts. The new functions have shown the inadequacy of the acoustics of this marbled and highly decorated room (Figure 2). www.mdpi.com/journal/buildings 2 of 14 Buildings 2016, 6, 1 Figure 1. Plans of the Royal Palace in Caserta, showing the position of the Palatine Chapel. Figure 1. Plans of the Royal Palace in Caserta, showing the position of the Palatine Chapel. The chapel is rectangular with a semi-circular apse at one end. On the opposite side to the apse is the entrance portal, above which is the royal tribune used by high dignitaries and the court ladies during sacral functions. Two galleries run along the side walls with double Corinthian columns that rise in support of a barrel vault with a richly decorated coffered ceiling. An abundance of colored marble characterizes most of the surfaces of the chapel. 2.1. Acoustic Parameters of Analysis In room acoustics, the reverberation time is the most common parameter and it can be described as the persistence of sound after a source has stopped. In particular, the reverberation time is the time needed to have a reduction of 60 dB in the sound pressure level. In sound diffuse rooms, the reverberation time has the advantage of being steady throughout the space and predictable using simple formulas. However, it requires the capability of creating an energy gain of more than 60 dB over the background noise, before being able to measure the 60 dB sound pressure decay. In this paper, the early decay time (EDT) which is the slope of the best-fit linear regression line of the initial 10 dB, between 0 and ´10 dB, of the decay was evaluated as it is often shown to correlate better to the early reverberation effect in the room. Several acoustic parameters defined in the ISO 3382-1 [4] were analyzed. These parameters have been defined in order to better describe the perception of a sound field, even though their prediction depends on many factors, such as the relative position of sources and receivers. In particular, this study focused on the values assumed by the center time, the clarity, and the definition. The center time (Ts) is defined as the time of the center of gravity of the squared impulse response of the sound energy, and it is related to the balance between early sound and delayed sound respect to the Ts value. In reverberant rooms such as churches, where late reflections reach listeners with a long delay, Ts can assume values up to several hundreds of milliseconds. Late sound contributes to have a long reverberation of the room and although it may improve the perception of the music, it is generally detrimental for listening to speeches. The clarity measures the balance between the useful and detrimental sound for the listening perception. It represents the degree to which different reflections arrives and are perceived by the listener, and it is assessed as an early-to-late arriving sound energy ratio. This ratio can be calculated for either a 50 ms or an 80 ms early time limit, depending on whether it relates to conditions for speech or music respectively. 1. Introduction A large icon painted by Giuseppe Bonito portraying the Immaculate Conception is suspended in the apse, while originally organ pipes are placed on the two side galleries. The Chapel suffered severe damages during World War II, and was then restored according to the original design. Figure 2. Views of the Palatine Chapel toward the apse (a) and toward the royal tribune (b). Figure 2. Views of the Palatine Chapel toward the apse (a) and toward the royal tribune (b). Figure 3 shows the floorplan and a cross section of the Palatine Chapel with its main geometrical dimensions. The total length of the chapel is 37 m, and the transversal width is 15 m, while the vault has a maximum height of 25 m. The inner volume is about 22,860 m3. It can be seen from Figure 2 that the chapel has highly decorated sound reflective surfaces. The instances of heritage preservation 3 of 14 Buildings 2016, 6, 1 suggest the use of transparent plastic chairs for audience seating, as seen in Figure 2, in order to show the aesthetic beauty of the marble floor. suggest the use of transparent plastic chairs for audience seating, as seen in Figure 2, in order to show the aesthetic beauty of the marble floor. Figure 3. Cross section and plan of the Palatine Chapel, with location of the sound source ( ) and of the receivers ( ). Figure 3. Cross section and plan of the Palatine Chapel, with location of the sound source ( ) and of the receivers ( ). The present study aims to explore feasible acoustical treatments to obtain better acoustic conditions for the events planned to be held in the chapel. Acoustical treatments had to consider the preservation of the heritage site. The study consisted of both field measurements inside the chapel and computer simulations of different intervention hypothesis with the aid of the software Odeon [3]. 2.1. Acoustic Parameters of Analysis In particular, the C80 is defined as the ratio, expressed in decibels, of the early energy (from 0 to 80 ms) over the late reverberant energy (from 80 ms to infinite). The definition (D50) considers the early arriving sound energy over the total sound energy and it is calculated using 50 ms as the early time limit. 4 of 14 Buildings 2016, 6, 1 Finally, the parameter of sound strength (G) was assessed since this is representative of the subjective level of sound, and it is defined as the gain from the sound pressure level, which is produced by the same sound source with the same power level in a free field at a distance of 10 m from the sound source. In order to establish suggested values of the different monaural acoustic parameters considered in this study different references were used. In this phase, it was important to select the most adequate function for this room. In order to guarantee a certain flexibility in the use, the room was supposed to host public meetings with speech comprehension (talks and receptions are common in this room), but also some baroque chamber music or small orchestra listening. The different requests of the several sound messages required some compromises in the acoustics goals. Using recent studies about the typical listening preference in sacred spaces [5–7], the following criteria were finally established: - The early decay time (EDT) should assume values between 1 s, a value adequate for a clearer perception of speeches, and 2.5 s, a value adequate for music listening preference. In churches reverberation time and early decay time values well above 3 s are common and may well fit for example with organ music. However, since this kind of music is not contemplated in the programming of the Palatine chapel anymore, a shorter reverberation was considered necessary; - The center time (Ts) should assume values below 100 ms for a clearer perception of speeches, while it may assume greater values, up to 200 or 250 ms for music listening preference; - The clarity (C80) expressing the balance between the early and late arriving energy, should have an higher value if the goal is to separate the initial sounds from the diffuse ones and making the discrete sounds stand apart from each other. 2.1. Acoustic Parameters of Analysis For the purposes of good listening conditions of music, it is generally preferable that C80 should be in the range between ´2 dB and 2 dB, while it is expected to be above 2 dB if speech perception is a priority; - The definition (D50) which may assume values from 0 to 1, should be above 0.50 for a good speech comprehension. - The definition (D50) which may assume values from 0 to 1, should be above 0.50 for a good speech comprehension. Obviously, the preferred values for the different parameters refer to fully occupied conditions so in a room such as the Palatine chapel, were the audience would represent the main sound absorbing surfaces, it is important to analyze the effect of the presence of the audience. 2.2. Acoustic Measurements The sound source used to perform acoustic measurements consisted of a dodecahedron loudspeaker Peeker Sound JA12 (Peeker Sound Corportation, Reggio Emilia, Italy). MLS signals of order 16 with a length of 5 s were generated by a 01 dB Symphonie system. The sound pressure was recorded with a ½” microphone GRAS 40 connected with a preamplifier 01 dB PRE 12 H. The floor plan in Figure 3 shows the location of the sound source and of the fifteen receivers. The sound source was placed at the height of 1.5 m over the floor at the center of the area in front of the altar where musicians are usually located during concerts. The measurement microphone was placed at the height of 1.5 m over the floor too. Measurements were done both in the empty conditions of the chapel or with transparent chairs that are generally used (Figure 2). The recorded impulse responses were then elaborated with the software Dirac 4.0 [5], and several acoustic parameters defined in the ISO 3382-1 [4], such as the early decay time (EDT), the center time (Ts), the clarity (C80), and the definition (D50) were analyzed. Figure 4 reports the measured values of EDT, Ts, C80, and D50, averaged among the fifteen receiver locations together with the intervals of the standard deviation for each octave band from 125 Hz to 4 kHz. All the measurements were done in unoccupied conditions. Obviously, the audience would have had an absorbing effect with a consequent reduction of the reverberation and hence of the EDT and Ts. However, the results of the measurements suggested that the hall in the observed state is clearly over reverberant and it is not well suited neither for chamber music nor for the intelligibility of speech. This led to study the possibility to introduce in this room some acoustic treatments. 5 of 14 Buildings 2016, 6, 1 Acoustic measurements with the presence of chairs were also realized using the same measurement equipment and setup described previously. The measurement with the chairs showed no significant difference in the reverberation parameter (EDT), while other parameters, such as C80 or Ts had more remarkable difference within the room. In fact, the sound scattering realized by the chairs reduced the clarity while increased the center time. Figure 4. 2.2. Acoustic Measurements Comparison between measured and simulated results averaged among the 15 receiver positions of four room acoustic parameters, EDT, Ts, C80, and D50, and their standard deviations. Figure 4. Comparison between measured and simulated results averaged among the 15 receiver positions of four room acoustic parameters, EDT, Ts, C80, and D50, and their standard deviations. 3.1. The Virtual Model To obtain realistic data for the Palatine Chapel in actual use, including the effect of audience, computer simulations were carried out using the software Odeon [3]. This software model was then used to study the effect of temporary sound absorbing systems that can be adopted in the respect of the architectural value of the venue. Odeon uses the principles of the geometrical acoustics and adopts a hybrid calculation method that combines the image source method and the ray-tracing method. The approach used by the software merges the best features of both models, since the image source method is used for the early-scattered rays of the first reflections, while a ray-tracing technique which also considers the surface scattering according to a Lambert’s cosine law, is used for the more statistically computed late part of the impulse response [8–10]. Early reflections are generated by point sources for which the reflection order is less than or equal to the Transition Order (TO). The early reflections take into account the scattering properties of the surfaces. Every time a ray is reflected at a surface, the position of an image source is found. In this early part of the impulse response calculation, rays are only used indirectly to detect image sources that are likely to be valid. The image sources are then split into a specular contribution and a scattering contribution which consists of secondary sources on the image-source surfaces, allowing for a realistic calculation of early scattering. All reflections that are not accounted for by the early reflection method are treated by the late-reflection method. Every Buildings 2016, 6, 1 6 of 14 time a late ray is reflected at a surface, a secondary source is generated, having directivity varying according to Lambert’s law. The late-reflection process keeps the reflection density constant in order to reduce the calculation time. Usually, a computer software simulation requires a first step aimed at the development of a model of the space as it exists and for which acoustic measurements are available. Unavoidable approximations about the geometry and the acoustic behavior of materials must be faced with. A second step consists of the comparison between measured and simulated parameters which allows a suitable calibration of the acoustic model in order to reduce the difference between measured and simulated acoustical parameters to minimal values or at least to a value below the just noticeable difference (JND) of each parameter. 3.1. The Virtual Model After having obtained a virtual model that represents adequately the observed state of a room, desired changes or insertions are considered [11,12]. In situ checks and detailed 3D drawings of the Palatine Chapel allowed the realization of the reticulated version of the geometry of the room (Figure 5). The number of surfaces in the model was 3849. The estimated inner surface amounted to 15,864 m2. Clearly, many details of the CAD drawings could not be handled. Based on previous experience and software suggestions for the given volume of the simulated room, the simulations were performed using the following parameters: TO = 2, impulse response length = 6 s., resolution = 3 ms, and number of rays = 50,000. Other parameters were assigned the default values of the software. Figure 5. Palatine Chapel: reticulated geometry (a) and rendering as given by Odeon (b). Figure 5. Palatine Chapel: reticulated geometry (a) and rendering as given by Odeon (b). 3.2. The Calibration of the Virtual Model The results of the difference expressed in JND as receiver-averaged values and the relevant standard deviation for each octave band showed satisfactory values (Figure 4). The highest errors were found in the octave band of 4 kHz for the EDT, and in that of 250 Hz for the Ts, C80, and D50. Overall, results in Figure 4 shows that the calibration was highly satisfactory. g y y In order to assess the effect of occupancy, the area where chairs are generally located was simulated as a series of boxes with a height of 0.8 m, with absorption coefficients typical of lightly upholstered seats, as reported in Table 1 [17–19]. In the virtual model, the area occupied by the public is 200 m2. Figure 6 shows the plan distribution of the occupancy, which was modeled as boxes. Table 1. Absorption and scattering coefficient used in the simulated model, data taken from [13–17]. Table 1. Absorption and scattering coefficient used in the simulated model, data taken from [13–17]. Material Absorption (α) Scattering (s) 125 Hz 250 Hz 500 Hz 1000 Hz 2000 Hz 4000 Hz Hard walls 0.048 0.047 0.045 0.05 0.053 0.03 0.05 Ceiling 0.145 0.13 0.14 0.145 0.098 0.06 0.01 Windows 0.35 0.25 0.18 0.12 0.07 0.02 0.05 Audience 0.51 0.64 0.75 0.80 0.82 0.78 0.70 The effect of the occupancy and the exact location of the source in historical churches have recently received increasing attention due to the highly reflective characteristics of these spaces [17,20]. In previous studies, it was found that the presence of the audience in churches determines a significant improvement of the monaural acoustical parameters, especially since the reverberation reduces once the presence of the audience is considered. Reversely, the sound source position has generally a limited effect over the reverberation time and a more significant impact on other acoustical parameters, as these strongly depend on the source-receiver position. The results in Figure 7 show that the presence of the public is not sufficient to make the acoustics of the chapel in line with the goals reported in Section 2. Consequently, some acoustic correction treatments based on sound-absorbing surfaces were implemented. These treatments are considered necessary since the early decay time in fully occupied conditions still resulted to be above 3 s at middle frequencies. Figure 6. 3.2. The Calibration of the Virtual Model Most of the internal surfaces of the Palatine Chapel are constituted by flat marbles, which is an acoustically reflective material. The vault is made of a thick structure composed of cocciopesto, a lime mortar with crushed pottery. A relatively small fraction of the inner envelope is constituted of windows, doors and a few canvases, which could have a more sound absorbing behavior. The initial values of the sound absorption (α) and sound scattering (s) were selected from literature data [12–17]. Then, in order to validate the acoustic model, measured averaged values of the different parameters were compared with the corresponding values calculated with the software. An iterative procedure was used to reduce the difference between the measured and calculated values. This implied little adjustments to the sound absorption and scattering coefficients [13]. In order to maintain the simplicity of the model together with its practicality, richly decorated surfaces were modelled as flat ones while the absorption and scattering coefficients were modified accordingly [17]. Figure 4 displays the results of the calibration of the virtual model of the Palatine Chapel, as well as the measured parameters, and it shows that the virtual model was able to obtain results particularly close to the measured ones. When measured and simulated are compared, it is a common practice in room acoustics to evaluate them in terms of the JND, the subjective limen of the specific parameter. This approach follows the common assumption that “what cannot be heard can be neglected” [14–16]. According to the standard ISO 3382 [4], the JND of the EDT is 5% of its value, while that of Ts, 7 of 14 Buildings 2016, 6, 1 C80, and D50 should be 10 ms, 1 dB, and 0.05, respectively. Thus, the precision of the simulated parameters was assessed in terms of number of JND. The results of the difference expressed in JND as receiver-averaged values and the relevant standard deviation for each octave band showed satisfactory values (Figure 4). The highest errors were found in the octave band of 4 kHz for the EDT, and in that of 250 Hz for the Ts, C80, and D50. Overall, results in Figure 4 shows that the calibration was highly satisfactory. C80, and D50 should be 10 ms, 1 dB, and 0.05, respectively. Thus, the precision of the simulated parameters was assessed in terms of number of JND. 3.2. The Calibration of the Virtual Model Plan distribution of the location of the audience (a), and position of banner treatments on the sides and in the apse (b). Figure 6. Plan distribution of the location of the audience (a), and position of banner treatments on the sides and in the apse (b). 8 of 14 8 of 14 Buildings 2016, 6, 1 Figure 7. Simulation results obtained considering the presence of the audience (full occupancy), and with the acoustic absorbing curtains or perforated panels along lateral walls and in the apse. Figure 7. Simulation results obtained considering the presence of the audience (full occupancy), and with the acoustic absorbing curtains or perforated panels along lateral walls and in the apse. 4. Acoustic Treatments Historic buildings, such as the Palatine Chapel, are heritage buildings whose cultural value prevents invasive or irreversible interventions. In this case, given the completely marbled nature of all the surfaces, permanent acoustic treatments to the room surfaces were not allowed. The need to create acoustic conditions closer to the actual needs led to evaluate removable elements that could be mounted and dismounted easily for specific events. Among the different acoustic treatment options, it was considered the possibility to adopt transparent vibrating banners, eventually micro-perforated, as well as heavy curtains. y Vibrating panels and perforated (or micro-perforated) ones once mounted at a given distance from a back rigid wall provide significant absorption at low frequencies. According to the theory, the largest absorption of vibrating panels occur for a distance from the rear wall of a quarter of the wavelength [21]. Micro-perforation in glazing or polycarbonate transparent panels were considered as a solution to get an absorber with a minimal visual presence. These panels being micro-perforated (with holes as small as 0.1 mm) behave as Helmholtz devices, but without the normal resistive material. The holes are drilled mechanically and provide absorption through high viscous losses as air passes through the holes. Micro-perforated transparent absorbers have reached an increasing attention since they are transparent when looked at from straight on, although at oblique angles the holes become more apparent although the surface is still translucent [21]. Panels with holes dimeters ranging between 0.1 and 0.2 mm and with a percentage of holes in the range between 8% and 10% of the surface were considered. Panels with a surface density of 0.48 kg/m2 and a thickness of 1.41 mm were then selected. Another category of acoustics treatments that was considered is that of heavy textile materials. The absorption of these surfaces have received increasing attention in room acoustics application [22]. Add curtains sustained by rigid frame next to the base of the lateral walls could guarantee high absorption especially at high frequency. Moreover, if the curtains were mounted at a given distance from the back wall, the sound absorption would also be higher at lower frequencies, as a consequence of the smaller impedance of the sound wave far from the wall. 4. Acoustic Treatments 9 of 14 Buildings 2016, 6, 1 Obviously, the specific effect of the absorption of curtains would depend on their distance from the back walls, but the typical drapes of curtains determine a significant variation of their distance from the rigid backing walls. This means that an exact determination of the sound absorption could not be defined. In order to simulate the effects of curtains, the literature values reported by Cox and D’Antonio for heavy curtains with a density of 610 g/m2 were used [22]. The absorption coefficient values of the different acoustic treatments considered for the acoustic intervention are reported in Table 2. Overall, the acoustic treatments consisted of 250 square meter panels, mainly distributed along the lateral walls each one with a height of 3.5 m from the floor (Figure 6). The treatments were considered as temporary elements to display in the room in occasion of specific events. In particular, the transparent vibrating panels, absorbing the low frequency could guarantee a more tonal balanced acoustics of the room, which would be highly beneficial for speech listening; reversely, the introduction of heavy curtains would represent an elegant way to reduce the reverberation of the room, although their acoustic effect would be more appreciable at higher frequencies. Table 2. Absorption coefficient of the acoustic treatments proposed in the Palatine chapel. Acoustic Treatment Frequency (Hz) 125 250 500 1000 2000 4000 Transparent micro-perforated panel 0.15 0.70 0.40 0.30 0.20 0.15 Heavy curtain banner 0.10 0.20 0.40 0.50 0.60 0.70 Table 2. Absorption coefficient of the acoustic treatments proposed in the Palatine chapel. Figure 7 shows the acoustic parameters of the fully occupied room and the effects of the addition of banners placed on the side walls and in the apse. It can be noticed that the chapel still remains with an excess of reverberation showing the typical behavior of large churches influenced by air absorption at high frequencies [23]. Overall, the simulated values showed that the investigated room with the proposed acoustic corrections has acoustical properties that could be considered adequate for musical performance. Figures 8 and 9 report the color maps at 1 kHz of the T30, C80, and STI in the configuration with the audience and with the heavy curtains and vibrating transparent micro-perforated panels respectively. 4. Acoustic Treatments The figures show that the homogeneity of the sound field through the room also with the introduction of sound absorbing treatments along the two sides. At middle frequencies, the area where the audience seats would have a reverberation time equal to 2.6 s with the treatments of the heavy curtain banners and to 2.8 s with the vibrating micro-perforated panels (Figure 7). The clarity reduces with the distance from the sound source, showing a remarkable behavior from values up to 8 dB closer to the sound source to values between ´2 dB and ˘2 dB in the rest of the chapel, both with the heavy curtains as well as with the vibrating panels. Finally, in order to assess the possibility to use this room for meetings, which involve speech listening, the Speech Transmission Index (STI) was considered. This parameter represents the degree of amplitude modulation in a speech signal and refers to the distortion in speech signals caused by reverberation, echoes, and background noise. This index can assume values between 0 and 1, being greater than 0.5 for favorable speech conditions. Results in Figures 8 and 9 show that the STI would be acceptable in the first half of the audience area, while the area farther from the sound source (simulated in the apse) would have a STI value around 0.45. Such a value generally corresponds to a “poor” speech listening condition. However, it should be stated that these results were obtained with an omnidirectional sound source. This means that a sound reinforcement system consisting of directive loudspeakers should be used for a better speech listening in order to have improved STI values even in the back of the Chapel if this has to host events were highly speech intelligibility is required. 10 of 14 Buildings 2016, 6, 1 gure 8. Color maps at 1 kHz of the T30, C80, and STI in the configuration with the audi oustic treatments heavy curtain banners (the maps only cover the area where the audi Figure 8. Color maps at 1 kHz of the T30, C80, and STI in the configuration with the audience and the acoustic treatments heavy curtain banners (the maps only cover the area where the audience seats). 11 of 14 Buildings 2016, 6, 1 e 9. 4. Acoustic Treatments Color maps at 1 kHz of the T30, C80, and STI in the configuration with the audienc rated transparent banners (the maps only cover the area where the audience seats). Figure 9. Color maps at 1 kHz of the T30, C80, and STI in the configuration with the audience and the perforated transparent banners (the maps only cover the area where the audience seats). 12 of 14 12 of 14 Buildings 2016, 6, 1 Figure 10. Sound strength (G) at the frequency of 250 Hz and 1 kHz in different configurations. Figure 10. Sound strength (G) at the frequency of 250 Hz and 1 kHz in different configurations. Figure 10. Sound strength (G) at the frequency of 250 Hz and 1 kHz in different configurations. A final evaluation of the acoustic interventions presented in this paper regarded the impact of the sound absorption materials over the sound strength. The sound strength was evaluated along the central axes of the Royal Chapel room both at 250 Hz and 1 kHz (Figure 10). The choice to check the sound absorption at both low and middle frequencies was due to the highly absorptive behavior of the vibrating panels at low frequencies. In fact, although the acoustics intervention with micro perforated vibrating panels aimed to absorb the low frequencies and hence to reduce the frequency unbalanced response of the rom, it was considered important to control the overall sound strength levels. The sound strength (G) was simulated in different scenarios: in the actual condition, with and without the audience, and after the introduction of the acoustic treatments of the banners. As expected, in the empty condition of the hall, the parameter G has higher values than when the audience and the acoustic treatments are introduced. In particular, in the room before the introduction of the acoustic treatments, the G decreases almost linearly closer to the sound source, while at a larger distance the sound field becomes diffuse and the G assumes more stable values. Reversely, after the introduction of the acoustics treatments the sound field does not become diffuse quickly, while the sound strength reduces with the distance from the sound source. References 1. United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage Sites. Available online: http://whc.unesco.org/en/list (accessed on 21 December 2015). 1. United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage Sites. Available online: http://whc.unesco.org/en/list (accessed on 21 December 2015). 2. Guide to the Royal Palace of Caserta, (In Italian: Guida Reggia di Caserta). Available online: http://reggiadicaserta.beniculturali.it/index.php/guida-guide/guida-alla-reggia/palazzo/ cappella-palatina.html (accessed on 21 December 2015). 2. Guide to the Royal Palace of Caserta, (In Italian: Guida Reggia di Caserta). Available online: http://reggiadicaserta.beniculturali.it/index.php/guida-guide/guida-alla-reggia/palazzo/ cappella-palatina.html (accessed on 21 December 2015). 3. Odeon, Version 2011. Room Acoustics Software, Version 11, Combined Edition by Christensen C.L., Odeon A/S, Scion DTU, Lyngby, Denmark. Available online: http://www.odeon.dk/specifications (accessed on 21 December 2015). 3. Odeon, Version 2011. Room Acoustics Software, Version 11, Combined Edition by Christensen C.L., Odeon A/S, Scion DTU, Lyngby, Denmark. Available online: http://www.odeon.dk/specifications (accessed on 21 December 2015). 4. ISO 3382-1 Acoustics-Measurement of Room Acoustic Parameters—Part 1: Performance Spaces; ISO: Geneva, Switzerland, 2009. 4. ISO 3382-1 Acoustics-Measurement of Room Acoustic Parameters—Part 1: Performance Spaces; ISO: Geneva, Switzerland, 2009. 5. Dirac 4.0 Manual, Bruel & Kjaer. Available online: http://www.bksv.com/ (accessed on 21 December 2015). 6. Berardi, U. A double synthetic index to evaluate the acoustics of churches. Arch. Acoust. 2012, 37, 521–528. [CrossRef] , j p // / ( ) 6. Berardi, U. A double synthetic index to evaluate the acoustics of churches. Arch. Acoust. 2012, 37, 521–528. [CrossRef] 6. Berardi, U. A double synthetic index to evaluate the acoustics of churches. Arch. Acoust. 2012, 37, 521–528. [CrossRef] 7. Martellotta, F. Subjective study of preferred listening conditions in italian catholic churches. J. Sound Vib. 2008, 317, 378–399. [CrossRef] 8. Katz, B.F.G. International round robin on room acoustical impulse response analysis software. Acoust. Res. Lett. Online 2004, 5, 158–164. [CrossRef] 9. Krokstad, A.; Strøm, S.; Sørsdal, S. Calculating the acoustical room response by the use of a ray tracing technique. J. Sound Vib. 1968, 8, 118–125. [CrossRef] 10. Patania, F.; Gagliano, A.; Nocera, F.; Galesi, A. Intervention of acoustic correction to improve speech quality of two conference halls in a Sicilian historical building (XVI sec.). In Proceedings of the 38th International Congress on Noise Control Engineering, Ottawa, Canada, 23–26 August 2009. Congress on Noise Control Engineering, Ottawa, Canada, 23–26 August 2009. 11. Bork, I. Report on the 3rd round robin on room acoustical computer simulation—Part I: Measurements. Acta Acust. United Acust. 2005, 91, 740–752. 12. Bork, I. 5. Conclusions This paper has reported a study about the acoustics in a cultural heritage buildings, the Palatine Chapel in the Royal Palace in Caserta (Italy). Average reverberation times of about 5 s recorded initially at mid frequencies in unoccupied conditions were deemed inappropriate for the public events hosted in this room nowadays. This situation requires to propose acoustics treatments that could modify the acoustics of the room, while respecting the historical and architectonical value of the room. Simulation techniques provided useful information for understanding how to improve the acoustics of this room. Firstly, simulations were used for to obtain realistic data about the current acoustics of the room in fully occupied conditions. The study showed that even in fully occupancy conditions, the reverberation time would still be too long. Hence a study of the effects of temporary acoustic treatments compatible with the specific nature of the room was carried out. For this scope, heavy curtains along the lateral walls as well as transparent vibrating panels were considered opportunities to introduce occasionally high sound absorption with minimal aesthetic or visual impact respectively. 13 of 14 13 of 14 Buildings 2016, 6, 1 The acoustic treatments that were proposed guaranteed a reduction of the reverberation to about 2.5 s at middle frequencies. The final acoustic characteristics were therefore considered acceptable for the functions hosted in this chapel while also considering the historical value of this cultural heritage. Author Contributions: Umberto Berardi, Gino Iannace and Carmine Ianniello contributed equally to this work. Conflicts of Interest: The authors declare no conflict of interest. Conflicts of Interest: The authors declare no conflict of interest. References Report on the 3rd round robin on room acoustical computer simulation—Part II: Calculations. Acta Acust. United Acust. 2005, 91, 753–763. 13. Zeng, X.; Christensen, C.L.; Rindel, J.H. Practical methods to define scattering coefficients in a room acoustics computer model. Appl. Acoust. 2006, 67, 771–786. [CrossRef] 14. Christensen, C.L.; Koutsouris, G.; Rindel, J.H. The ISO 3382 parameters: Can we simulate them? Can we measure them? In Proceedings of the International Symposium on Room Acoustics, Toronto, ON, Canada, 9–10 June 2013. 15. Galindo, M.; Zamarreno, T.; Girón, S. Acoustic simulations of Mudejar-Gothic churches. J. Acoust. Soc. Am. 2009, 126, 1207–1218. [CrossRef] [PubMed] 16. Vorländer, M. Computer simulations in room acoustics: Concepts and uncertaintie. J. Acoust. Soc. Am. 2013, 133, 1203–1213. [CrossRef] [PubMed] 17. Berardi, U. Simulation of acoustical parameters in rectangular churches. J. Build. Perform. Simul. 2014, 7, 1–16. [CrossRef] 18. Hidaka, T.; Nishihara, N.; Beranek, L.L. Mechanism of sound absorption by seated audiences in concert halls. J. Acoust. Soc. Am. 1996, 100, 2705–2706. [CrossRef] 19. Beranek, L.L.; Hidaka, T. Sound absorption in concert halls by seats, occupied and unoccupied, and by the hall’s interior surfaces. J. Acoust. Soc. Am. 1998, 104, 3169–3177. [CrossRef] 20. Alvarez-Morales, L.; Martellotta, F. A geometrical acoustic simulation of the effect of occupancy and source position in historical churches. Appl. Acoust. 2015, 91, 47–58. [CrossRef] 14 of 14 14 of 14 Buildings 2016, 6, 1 21. Berardi, U.; Cirillo, E.; Martellotta, F. A comparative analysis of energy models in churches. J. Acoust. Soc. Am. 2009, 126, 1838–1849. [CrossRef] [PubMed] 22. Asdrubali, F.; Pispola, G. Properties of transparent sound-absorbing panels for use in noise barriers. J. Acoust. Soc. Am. 2007, 121, 214–221. [CrossRef] 23. D’Antonio, P.; Cox, T. Technical Bulletin on the Design of Microperforated Transparent Absorbers; RPG Diffusor Systems, Inc., 2005. Available online: http://www.rpginc.com/docs/ Technology/White%20Papers/Clearsorber%20White%20Paper.pdf (accessed on 21 December 2015). © 2015 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons by Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).
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Mass and Heat Transfer During Two-Phase Flow in Porous Media - Theory and Modeling
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0 1 Mass and Heat Transfer During Two-Phase Flow in Porous Media - Theory and Modeling Jennifer Niessner1 and S. Majid Hassanizadeh2 1 Institute 2 Department of Hydraulic Engineering, University of Stuttgart, Stuttgart of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht 1 Germany 2 The Netherlands 1. Introduction 1.1 Motivation This chapter focusses on the description and modeling of mass transfer processes occurring between two fluid phases in a porous medium. The principle underlying physical process comprises a transport of particles from one phase to the other phase. This process takes place across fluid–fluid interfaces (see Fig. 1) and may constitute evaporation, dissolution, or condensation, for example. Such mass transfer processes are crucial in many applications involving flow and transport in porous media. Major examples are found in soil science (where the evaporation from soils is of interest), soil and groundwater remediation (like thermally-enhanced soil vapor extraction where dissolution, evaporation, and condensation play a role), storage of carbon dioxide in the subsurface (where the dissolution of carbon dioxide in the surrounding groundwater is a crucial storage mechanism), CO2 -enhanced oil recovery (where after primary and secondary recovery, carbon dioxide is injected into the reservoir in order to mobilize an additional 8-20 per cent of oil), and various industrial porous systems (such as certain types of fuel cells). Let us have a closer look at a few of these applications and identify where interphase mass transfer is relevant. Four specific examples are shown in Fig. 2 and briefly described. solid phase fluid phase 1 fluid phase 2 Fig. 1. Mass transfer processes (evaporation, dissolution, condensation) imply a transfer of particles across fluid–fluid interfaces. www.intechopen.com 2 2 Transfer Mass Transfer in Multiphase Systems andMass its Applications (a) Carbon dioxide storage in the subsurface (figure from IPCC (2005)) (b) Soil contamination and remediation precipitation radiation infiltration evaporation groundwater (c) Enhanced www.oxy.com) oil recovery (figure from (d) Evaporation from soil Fig. 2. Four applications of flow and transport in porous media where interphase mass transfer is important www.intechopen.com Massand andHeat HeatTransfer TransferDuring During Two-Phase Flow in Porous Media - Theory and Modeling Mass Two-Phase Flow in Porous Media - Theory and Modeling 33 (a) Carbon capture and storage (Fig. 2 (a)) is a recent strategy to mitigate the greenhouse effect by capturing the greenhouse gas carbon dioxide that is emitted e.g. by coal power plants and inject it directly into the subsurface below an impermeable caprock. Here, three different storage mechanisms are relevant on different time scales: 1) The capillary barrier mechanism of the caprock. This geologic layer is meant to keep the carbon dioxide in the storage reservoir as a separate phase. 2) Dissolution of the carbon dioxide in the surrounding brine (salty groundwater). This is a longterm storage mechanism and involves a mass transfer process as carbon dioxide molecules are “transferred” from the gaseous phase to the brine phase. 3) Geochemical reactions which immobilize the carbon dioxide through incorporation into the rock matrix. (b) Shown in Fig. 2 (b) is a cartoon of a light non-aqueous phase liquid (LNAPL) soil contamination and its clean up by injection of steam at wells located around the contaminated soil. The idea behind this strategy is to mobilize the initially immobile (residual) LNAPL by evaporation of LNAPL component at large rates into the gaseous phase. The soil gas is then extracted by a centrally located extraction well. It means that the remediation mechanism relies on the evaporation of LNAPL component which represents a mass transfer from the liquid LNAPL phase into the gaseous phase. (c) In order to produce an additional 8-20% of oil after primary and secondary recovery, carbon dioxide may be injected into an oil reservoir, e.g. alternatingly with water, see Fig. 2 (c). This is called enhanced oil recovery. The advantage of injecting carbon dioxide lies in the fact that it dissolves in the oil which in turn reduces the oil viscosity, and thus, increases its mobility. The improved mobility of the oil allows for an extraction of the otherwise trapped oil. Here, an interphase mass transfer process (dissolution) is responsible for an improved recovery. (d) The last example (Fig. 2 (d)) shows the upper part of the soil. The water balance of this part of the subsurface is extremely important for agriculture or plant growth in general. Plants do not grow well under too wet or too dry conditions. One of the very important factors influencing this water balance (besides surface runoff and infiltration) is the evaporation of water from the soil, which is again an interphase mass transfer process. 1.2 Purpose of this work Mass transfer processes are essential in a large variety of applications—the presented examples only show a small selection of systems. A common feature of all these applications is the fact that the relevant processes occur in relatively large domains such that it is not possible to resolve the pore structure and the fluid distribution in detail (left hand side of Fig. 3). Instead, a macro-scale approach is needed where properties and processes are averaged over a so-called representative elementary volume (right hand side of Fig. 3). This means that the common challenge in all of the above-mentioned applications is how to describe mass transfer processes on a macro scale. This transition from the pore scale to the macro scale is illustrated in Fig. 3 where on the left side, the pore-scale situation is shown (which is impossible to be resolved in detail) while on the right hand side, the macro-scale situation is shown. 2. Overview of classical mass transfer descriptions 2.1 Pore-scale considerations In order to better understand the physics of interphase mass transfer, which is essential to provide a physically-based description of this process, we start our considerations on the pore www.intechopen.com 4 4 Transfer Mass Transfer in Multiphase Systems andMass its Applications n w non−wetting fluid phase wetting fluid phase s solid phase macro scale pore scale Fig. 3. Pore-scale versus macro-scale description of flow and transport in a porous medium. scale. From there, we try to get a better understanding of the macro-scale physics of mass transfer, which is our scale of interest. In Fig. 1 we have seen that interphase mass transfer is inherently a pore-scale process as it—naturally—takes place across fluid–fluid interfaces. Let us imagine a situation where two fluid phases, a wetting phase and a non-wetting phase, are brought in contact as shown in Fig. 4. Commonly, when the two phases are brought in contact (time t = t0 ), equilibrium is quickly established directly at the interface. With respect to mass transfer, this means that the concentration of non-wetting phase particles in the wetting phase at the interface as well as the concentration of wetting-phase particles in the non-wettting phase at the interface are 1 . At t = t , away from the interface, there 2 both at their equilibrium values, C1,eq and C2,eq 0 is still no presence of α-phase particles in the β-phase. At a later time t = t1 , concentration profiles develop within the phases. However, within the bulk phases, the concentrations are still different from the respective equilibrium concentration at the interface. Considering a still later point of time, t = t2 , the equilibrium concentration is finally reached everywhere in the bulk phases. These considerations show that mass transfer on the pore scale is inherently a kinetic process that is very much related to phase-interfaces. But how is this process represented on the macro scale, i.e. on a volume-averaged scale? This is what we will focus on in the next section. t = t0 t = t1 t = t2 solid phase solid phase solid phase fluid phase 1 fluid phase 1 fluid phase 2 C C 2 2 C1,eq 1 C2,eq 1 C2,eq 1 C2,eq x Fig. 4. Pore-scale picture of interphase mass transfer. www.intechopen.com fluid phase 2 C C1,eq 2 C1,eq fluid phase 1 fluid phase 2 x x Massand andHeat HeatTransfer TransferDuring During Two-Phase Flow in Porous Media - Theory and Modeling Mass Two-Phase Flow in Porous Media - Theory and Modeling 55 2.2 Current macro-scale descriptions In Fig. 3, we illustrated the fact that when going from the pore scale to the macro scale, information about phase-interfaces is lost. The only information present on the macro scale is related to volume ratios, such as porosity and fluid saturations. But, as mentioned earlier, mass transfer is strongly linked to the presence of interfaces and interfacial areas and all the information about phase-interfaces disappears on the macro scale. This means that the description of mass transfer on the macro scale is not straight forward. Classical approaches for describing mass transfer generally rely on one of the following two principles: 1. assumption of local chemical equilibrium within an averaging volume or 2. kinetic description based on a fitted (linear) relationship. These two classical approaches will be discussed in more detail in the following. An alternative approach which accounts for the phase-interfacial area will be presented later in Sec. 3. 2.2.1 Local equilibrium assumption The assumption of local chemical equilibrium within an averaging volume means that the equilibrium concentrations are reached instantaneously everywhere within an averaging volume (in both phases). That means it is assumed that everywhere within the averaging volume, the situation at t = t2 in Fig. 4 is reached from the beginning (t = t0 ). Thus, at each point in the wetting phase and at each point in the non-wetting phase within the averaging volume, the equilibrium concentration of the components of the other phase is reached. This is an assumption which may be good in case of fast mass transfer, but bad in case of slow mass transfer processes. To be more precise, the assumption that the composition of a phase is at or close to equilibrium may be good if the characteristic time of mass transfer is small compared to that of flow. However, if large flow velocities occur as e.g. during air sparging, the local equilibrium assumption gives completely wrong results, see Falta (2000; 2003) and van Antwerp et al. (2008). We will investigate and quantify this issue later in Sec. 3.3 . Local equilibrium models for multi-phase systems have been introduced and developed e.g. by Miller et al. (1990); Powers et al. (1992; 1994); Imhoff et al. (1994); Zhang & Schwartz (2000) and have been used and advanced ever since. Let us consider a system with a liquid phase (denoted by subscript l) and a gaseous phase (denoted by subscript g) composed of air and water components. Then, Henry’s Law is employed to determine the mole fraction of air in the liquid phase, while the mole fraction of water in the gas phase is determined by assuming that the vapor pressure in the gas phase is equal to the saturation vapor pressure. Denoting the water component by superscript w and the air component by superscript a, this yields xla xw g = p ag · Hla− g (1) = pw sat (2) pg , where xla [−] is the mole fraction of air in the liquid phase, x w g [−] is the mole fraction of water   1 a in the gaseous phase, Hl − g Pa is the Henry constant for the dissolution of air in the liquid a phase, pw sat [ Pa ] is the saturation vapor pressure of water, p g [ Pa ] is the partial pressure of air www.intechopen.com 6 6 Transfer Mass Transfer in Multiphase Systems andMass its Applications in the gas phase while p g [ Pa] is the gas pressure. The remaining mole fractions result simply from the condition that mole fractions in each phase have to sum up to one, xlw x ga = = 1 − xla 1− xw g. (3) (4) Note that while for a number of applications the equilibrium mole fractions are constants or merely a function of temperature, in our case, they will be functions of space and time as pressure and the composition of the phases changes. 2.2.2 Classical kinetic approach Kinetic mass transfer approaches are traditionally applied to the dissolution of contaminants in the subsurface which form a separate phase from water, the so-called non-aqueous phase liquids (NAPLs). If such a non-aqueous phase liquid is heavier than water, it is called “dense non-aqueous phase liquid” or DNAPL. When an immobile lense of DNAPL is present at residual saturation (i.e. at a saturation which is so low that the phase is immobile) and dissolves into the surrounding groundwater, the kinetics of this mass transfer process usually plays an important role: the dissolution of DNAPL is a rate-limited process. This is also the case when a pool of DNAPL is formed on an impermeable layer. In these relatively simple cases, only the mass transfer of a DNAPL component from the DNAPL phase into the water phase has to be considered. For these cases, classical models acknowledge the fact that the rate of mass transfer is highly dependent (proportional to) interfacial area and assume a first-order rate of kinetic mass transfer between fluid phases in a porous medium on a macroscopic (i.e. volume-averaged) scale which can be expressed as (see e.g. Mayer & Hassanizadeh (2005)): κ Qκα→ β = kκα→ β aαβ (Cβ,s − Cβκ ), (5)   kg where Qκα→ β m3 s is the interphase mass transfer rate of component κ from phase α to     phase β, kκα→ β ms is the mass transfer rate coefficient, aαβ m1 is the specific interfacial   kg κ area separating phases α and β, Cβ,s is the solubility limit of component κ in phase m3   kg β, and finally, Cβκ m3 is the actual concentration of component κ in phase β. The actual κ . The case C κ = C κ corresponds concentration is not larger than the solubility limit, Cβκ ≤ Cβ,s β β,s to the local equilibrium case. In the absence of a physically-based estimate of interfacial area in classical kinetic models, the mass transfer coefficient kκα→ β and the specific interfacial area aαβ are often lumped into one single parameter (Miller et al. (1990); Powers et al. (1992; 1994); Imhoff et al. (1994); Zhang & Schwartz (2000)). This yields, in a simplified notation, Q = k(Cs − C ). (6) Here, Cs is the solubility limit of the DNAPL component in water and C is its actual   1 concentration. The lumped mass transfer coefficient k s is commonly related to a modified Sherwood number Sh by Dm k = Sh 2 , (7) d50 www.intechopen.com Massand andHeat HeatTransfer TransferDuring During Two-Phase Flow in Porous Media - Theory and Modeling Mass Two-Phase Flow in Porous Media - Theory and Modeling 77  2 where Dm ms is the aqueous phase molecular diffusion coefficient, and d50 [m] is the mean size of the grains. The Sherwood number is then related to Reynold’s number Re and DNAPL saturation Sn [−] by Sh = pReq Snr , (8) where p, q, and r are dimensionless fitting parameters. This is a purely empirical relationship. Although interphase mass transfer is proportional to specific interfacial area in the original Eq. (5), this dependence cannot explicitly be accounted for as the magnitude of specific interfacial area is not known. An alternative classical approach for DNAPL pool dissolution has been proposed by Falta (2003) who modeled the dissolution of DNAPL component by a dual domain approach for a case with simple geometry. For this purpose, they divided the contaminated porous medium into two parts: one that contains DNAPL pools and one without DNAPL. For their simple case, the dual domain approach combined with an analytical solution for steady-state advection and dispersion provided a means for modeling rate-limited interphase mass transfer. While this approach provided good results for the case of simplified geometry, it might be oversimplified for the modeling of realistic situations. 3. Interfacial-area-based approach for mass transfer description 3.1 Theoretical background Due to a number of deficiencies of the classical model for two-phase flow in porous media (one of which is the problem in describing kinetic interphase mass transfer on the macro scale), several approaches have been developed to describe two-phase flow in an alternative and thermodynamically-based way. Among these are a rational thermodynamics approach by Hassanizadeh & Gray (1980; 1990; 1993b;a), a thermodynamically constrained averaging theory approach by Gray and Miller (e.g. Gray & Miller (2005); Jackson et al. (2009)), mixture theory (Bowen (1982)) and an approach based on averaging and non-equilibrium thermodynamics by Marle (1981) and Kalaydjian (1987). While Marle (1981) and Kalaydjian (1987) developed their set of constitutive relationships phenomenologically, Hassanizadeh & Gray (1990; 1993b); Jackson et al. (2009), and Bowen (1982) exploited the entropy inequality to obtain constitutive relationships. To the best of our knowledge, the two-phase flow models of Marle (1981); Kalaydjian (1987); Hassanizadeh & Gray (1990; 1993b); Jackson et al. (2009) are the only ones to include interfaces explicitly in their formulation allowing to describe hysteresis as well as kinetic interphase mass and energy transfer in a physically-based way. In the following, we follow the approach of Hassanizadeh & Gray (1990; 1993b) as it includes the spatial and temporal evolution of phase-interfacial areas as parameters which allows us to model kinetic interphase mass transfer in a much more physically-based way than is classically done. It has been conjectured by Hassanizadeh & Gray (1990; 1993b) that problems of the classical two-phase flow model, like the hysteretic behavior of the constitutive relationship between capillary pressure and saturation, are due to the absence of interfacial areas in the theory. Hassanizadeh and Gray showed (Hassanizadeh & Gray (1990; 1993b)) that by formulating the conservation equations not only for the bulk phases, but additionally for interfaces, and by exploiting the residual entropy inequality, a relationship between capillary pressure, saturation, and specific interfacial areas (interfacial area per volume of REV) can be derived. This relationship has been determined in various experimental works (Brusseau et al. (1997); Chen & Kibbey (2006); Culligan et al. (2004); Schaefer et al. (2000); Wildenschild et al. (2002); www.intechopen.com 8 8 Transfer Mass Transfer in Multiphase Systems andMass its Applications Chen et al. (2007)) and computational studies (pore-network models and CFD simulations on the pore scale, see Reeves & Celia (1996); Held & Celia (2001); Joekar-Niasar et al. (2008; 2009); Porter et al. (2009)). The numerical work of Porter et al. (2009) using Lattice Boltzman simulations in a glass bead porous medium and experiments of Chen et al. (2007) show that the relationship between capillary pressure, the specific fluid-fluid interfacial area, and saturation is the same for drainage and imbibition to within the measurement error. This allows for the conclusion that the inclusion of fluid–fluid interfacial area into the capillary pressure–saturation relationship makes hysteresis disappear or, at least, reduces it down to a very small value. Niessner & Hassanizadeh (2008; 2009a;b) have modeled two-phase flow—using the thermodynamically-based set of equations developed by Hassanizadeh & Gray (1990)—and showed that this interfacial-area-based model is indeed able to model hysteresis as well as kinetic interphase mass and also energy transfer in a physically-based way. 3.2 Simplified model After having presented the general background of our interfacial-area-based model, we will now proceed by discussing the mathematical model. The complete set of balance equations based on the approach of Hassanizadeh & Gray (1990) is too large to be handled numerically. In order to do numerical modeling, simplifying assumptions need to be made. In the following, we present such a simplified equation system as was derived in Niessner & Hassanizadeh (2009a). This set of balance equations can be described by six mass and three momentum balance equations. These numbers result from the fact that mass balances for each component of each phase and the fluid–fluid interface (that is 2 × 3) while momentum balances are given for the bulk phases and the interface. Governing equations were derived by Hassanizadeh & Gray (1979) and Gray & Hassanizadeh (1989; 1998) for the case of flow of two pure fluid phases with no mass transfer. Extending these equations to the case of two fluid phases, each made of two components, we obtain the following equations. mass balance for phase components (κ = w, a):    ∂ φSl ρ̄l X̄lκ κ + ∇ · (φSl ρ̄l X̄lκ v̄l ) − ∇ · φSl j̄l ∂t    1 = ρ̄l Qκl + (9) ρl Xlκ vlg − vl + jκ · nlg dA l V Alg    ∂ φSg ρ̄ g X̄gκ κ + ∇ · φSg ρ̄ g X̄gκ v̄ g − ∇ · φSg j̄ g ∂t    1 = ρ̄ g Qκg + (10) ρ g Xgκ v g − vlg − jκ · nlg dA g V Alg mass balance for lg-interface components (κ = w, a):  κ a   ∂ Γ̄lg X̄lg lg κ κ + ∇ · Γ̄lg X̄lg alg v̄lg − ∇ · j̄ alg − lg ∂t     1 ρl Xlκ vl − vlg − jκ − ρ g Xgκ v g − vlg + jκ · nlg dA = l g V Alg www.intechopen.com (11) Massand andHeat HeatTransfer TransferDuring During Two-Phase Flow in Porous Media - Theory and Modeling Mass Two-Phase Flow in Porous Media - Theory and Modeling 99 momentum balance for phases: = = ∂ (φSl ρ̄l v̄l ) + ∇ · (φSl ρ̄l v̄l v̄l ) − ∇ · (φSl T l ) ∂t    1 ρl vl vlg − vl + tl · nlg dA V Alg    ∂ φSg ρ̄ g v̄ g + ∇ · φSg ρ̄ g v̄ g v̄ g − ∇ · φSg T g ∂t    1 ρ g v g v g − vlg − t g · nlg dA V Alg momentum balance for lg-interface:    ∂ Γ̄lg v̄lg alg + ∇ · Γ̄lg v̄lg alg v̄lg − ∇ · T lg alg ∂t     1 = ρl vl vl − vlg − tl − ρ g v g v g − vlg + t g · nlg dA, V Alg (12) (13) (14) κ where the overbars denote volume-averaged (macro-scale)  3  quantities. Here, Xα [−] is the mass fraction of component κ in phase α, t is time, Qκα ms is an external source of component   kg·m4 κ in phase α, jκ is the diffusive flux of component κ in phase α, V is the magnitude of s α the averaging volume, Alg denotes the interfaces separating the l-phase and the g-phase in an   averaging volume, vlg ms is the velocity of the lg-interface, and nlg is the unit vector normal κ [−] is the mass fraction of component κ to Alg and pointing into the g-phase. Furthermore, Xlg     4 kg kg · m is the diffusive flux of component κ in the lg-interface, tα m·s2 in the lg-interface, jκ s lg   kg is the α-phase micro-scale stress tensor, T α s2 is the α-phase macro-scale stress tensor, and   kg T lg s2 is the macro-scale lg-interfacial stress tensor. In the following, we provide a simplified version of Eq. (9) through (14). First, we assume that the composition of the interface does not change. This is a reasonable assumption as long as no surfactants are involved. This reduces the number of balance equations to eight, as we can sum up the mass balance equations for interface components. Furthermore, we assume that momentum balances can be simplified so far that we end up with Darcy-like equations for both bulk phases and interface. We further proceed by applying Fick’s law to relate the micro-scale diffusive fluxes jκ to the local concentration gradient resulting in the following α approximation:  κ  ρα Dκ jκ · nlg = ± κ alg Xα,s − Xακ , (15) α d  2 where Dκ ms is the micro-scale Fickian diffusion coefficient for component κ, dκ [m] is the κ [−] is the solubility limit of component κ in phase α diffusion length of component κ, Xα,s (i.e. the mass fraction corresponding to local equilibrium), and Xακ [−] is the micro-scale mass fraction of component κ in phase α at a distance dκ away from the interface. Niessner & www.intechopen.com 10 10 Transfer Mass Transfer in Multiphase Systems andMass its Applications Hassanizadeh (2009a) obtained the following determinate set of macro-scale equations:    ∂ φSl ρ̄l X̄lw w + ∇ · (ρ̄l X̄lw v̄l ) − ∇ · j̄l ∂t  D w ρ̄ g w w = ρl Qw l − dw alg X g,s − X g    ∂ φSl ρ̄l X̄la a + ∇ · (ρ̄l X̄la v̄l ) − ∇ · j̄l ∂t  D a ρ̄ a − Xla = ρl Qla + a l alg Xl,s d  ∂ φSg ρ̄ g X̄gw + ∂t =  ∂ φSg ρ̄ g X̄ga + ∂t = ∂alg ∂t  + ∇ · alg vlg = Elg v̄l = −K v̄ g = v̄lg + Xla + Xga = = = = = −Klg ∇ alg p g − pl 1 1 1 alg = alg (Sl , pc ), pc Sl + S g Xlw Xgw   w ∇ · ρ̄ g X̄gw v̄ g − ∇ · j̄ g  D w ρ̄ g w ρ g Qw alg Xg,s − Xgw g + w d   a ∇ · ρ̄ g X̄ga v̄ g − ∇ · j̄ g  D a ρ̄ a − Xla ρ g Q ag − a l alg Xl,s d Sl2  ∇ pl − ρ̄l g µl S2g  −K ∇ p g − ρ̄ g g µg (16) (17) (18) (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) κ α The macro-scale mass fluxes j̄ are given by a Fickian dispersion equation, κ α j̄ = −ρα D̄ακ ∇ ( X̄ακ ) , (29) where D̄ακ is the macro-scale dispersion coefficient. Note that in Eq. (16) through (19), we have acknowledged the fact that an internal source of a component in one of the phases must correspond to a sink of that component of equal magnitude in the other phase. The w and X a are obtained from a local equilibrium assumption at the solubility limits Xg,s l,s fluid–fluid interface. If, for example, we consider a two-phase–two-component air–water system solubility limits with respect to mole fractions are given by Eqs. (1) and (2). www.intechopen.com Massand andHeat HeatTransfer TransferDuring During Two-Phase Flow in Porous Media - Theory and Modeling Mass Two-Phase Flow in Porous Media - Theory and Modeling 11 11 3.3 Is a kinetic approach necessary? Depending on the parameters, initial conditions, and boundary conditions of the system, kinetics might be important for mass transfer. If so, then it may not be sufficient to use a classical local equilibrium model instead of the more complex interfacial-area-based model. To allow for a decision, Niessner & Hassanizadeh (2009a) make the system of equations (16) through (28) dimensionless and study the dependence of kinetics on Damköhler number and Peclet number. To do so, they define dimensionless variables: t∗ = a∗lg = ∗ Elg = p∗α = tv R , φL alg a R,lg ∇ ∗ = L ∇, a R,lg φL vR pα , pR D̄ακ ∗ = , D̄ακ , DR,α g∗ = Elg , α p∗c = v̄∗α = pc , pR v̄α , vR v∗lg = ρ̄α gL pR Qκα L κ v , Xα,s R (30) φ v , v R lg ∗ Klg = , ρ∗g = Qκα∗ = ρ̄ g ρ̄l (31) φKlg La R,lg v R µ∗l = , (32) µl . µg (33) Here, ρ∗g is density ratio, µ∗l is viscosity ratio, v R is a reference velocity, L is a characteristic length, a R,lg is a reference specific interfacial area, DR,α is a reference dispersion coefficient, and p R is a reference pressure. We assume that p R and v R can be chosen such that Also, Peclet number Peα and Damköhler number Daκ are defined by Peα = vR L , DR,α Daκ = Dκ La R,lg dv R Kp R µl v R L . = 1. (34) These definitions lead to the following dimensionless form of Eq. (16) through (28): Dlw∗ ∗ w ∇ X̄l Pel Dla∗ ∗ a ∂ ∗ a ∗ ∗ a − ∇ · v + ∇ · S ∇ X̄l X̄ X̄ ) ) ( ( l l l l ∂t∗ Pel   Dgw∗ ∗ w ∂  ∗ ∗ w ∗ w ∇ X̄g Sg X̄g + ∇ · X̄g v g − ∇ · ∂t∗ Peg   Dga∗ ∗ a ∂  ∗ ∗ a ∗ a Sg X̄g + ∇ · X̄g v g − ∇ · ∇ X̄g ∂t∗ Peg ∂ (S X̄ w ) + ∇∗ · ( X̄lw v∗l ) − ∇∗ · ∂t∗ l l ∂a∗lg ∂t∗ www.intechopen.com  + ∇∗ · a∗lg v∗lg =  w w ∗ w ∗ ∗ Qw l − Da alg ρ g X g,s − X̄ g (35) =  a Qla∗ + Daa a∗lg Xl,s − X̄la (36) =  ∗ w ∗ w w Qw g + Da alg X g,s − X̄ g (37) = = v∗l = v∗g = 1  a Q ag∗ − Daa a∗lg ∗ Xl,s − X̄la (38) ρg ∗ Elg (39)  −Sl2 ∇∗ p∗l − g∗l  −S2g µ∗l ∇∗ p∗g − g∗g (40) (41) 12 12 Transfer Mass Transfer in Multiphase Systems andMass its Applications v∗lg = ∗ ∗ ∗ −Klg ∇ alg (42) p∗c = = = = p∗g − p∗l (43) 1 (44) 1 (45) 1 (46) = a∗lg (Sl , p∗c ) . (47) Sl + S g X̄lw + X̄la X̄gw + X̄ga a∗lg In order to investigate the importance of kinetics, we define Pe := Pel = Peg and Da := Daw = Daa and vary Pe and Da independently over five orders of magnitude. Therefore, we consider a numerical example where dry air is injected into a horizontal (two-dimensional) porous medium of size 0.7 m × 0.5 m that is almost saturated with water (initial and boundary water saturation of 0.9). a Fig. 5 shows a comparison of actual mass fractions X̄la and X̄gw to solubility mass fractions Xl,s w and Xg,s for five different Damköhler numbers. Therefore, a cut through the domain is shown and two different time steps are compared. Da=0.1 Da0 Da=0.01 Da0 4.0E-5 4E−5 Da=Da0 4.0E-5 4E−5 Da=10 Da0 4.0E-5 4E−5 Da=100 Da0 4.0E-5 4E−5 4.0E-5 4E−5 a Xl [−] t = 0.0035s 0m x 0.7m 0.7 00 0.014 0.014 0m x 0.7m 0.7 00m 0 x 0.7m 0.7 00m 0 x 0.7m 0.7 00 0.014 0.014 0m x 0.7m 0.7 0m x 0.7m 0.7 00m 0 x 0.7m 0.7 00m 0 x 0.7m 0.7 00 0.014 0.014 00 0.014 0.014 00m 0 0.014 0.014 x 0.7m 0.7 w Xg [−] 4.0E-5 4E−5 4.0E-5 4E−5 4.0E-5 4E−5 4.0E-5 4E−5 00m 0 x 0.7m 0.7 4.0E-5 4E−5 a Xl [−] 00m 0 t = 0.01s x 0.7m 0.7 0.014 0.014 00m 0 x 0.7m 0.7 0.014 0.014 00m 0 x 0.7m 0.7 0.014 0.014 00m 0 x 0.7m 0.7 0.014 0.014 00m 0 x 0.7m 0.7 0.014 0.014 w Xg [−] 00m 0 x 0.7m 0.7 00m 0 x 0.7m 0.7 00m 0 x 0.7m 0.7 00m 0 x 0.7m 0.7 00m 0 x 0.7m 0.7 solubility limit actual mass fraction a and X w and actual mass fractions X̄ a and X̄ w for two different Fig. 5. Solubility limits Xl,s g g,s l time steps (0.0035 s and 0.01 s) and 5 different Damköhler numbers. www.intechopen.com Massand andHeat HeatTransfer TransferDuring During Two-Phase Flow in Porous Media - Theory and Modeling Mass Two-Phase Flow in Porous Media - Theory and Modeling 13 13 It can be seen that the system is practically instantaneously in equilibrium with respect to the mass fraction X̄gw (water mass fraction in the gas phase) for the whole range of considered Damköhler numbers (see the second and forth row of graphs). With respect to the mass fraction X̄la (air mass fraction in the water phase), for low Damköhler numbers and early times, the system is far from equilibrium (see the first and third row of graphs). With increasing time and with increasing Damköhler number, the system approaches equilibrium. As for high Damköhler numbers mass transfer is very fast, an ”overshoot“ occurs and the system becomes oversaturated before it reaches equilibrium. One might argue that the considered time steps are extremely small and not relevant for the time scale relevant for the whole domain. However, what happens at this very early time has a large influence on the state of the system at all subsequent times. It turned out that for different Peclet numbers, there is no difference in results. That means that kinetic interphase mass transfer is independent of Peclet number, at least within the four orders of magnitude considered here. 4. Extension to heat transfer The concept of describing mass transfer based on modeling the evolution of interfacial areas using the thermodynamically-based approach of Hassanizadeh & Gray (1990; 1993b) can be extended to describing interphase heat transfer as well. The main difference between interphase mass and heat transfer is that, in addition to fluid–fluid interfaces, heat can also be transferred across fluid–solid interfaces, see Fig. 6. Similarly to mass transfer, classical two-phase flow models describe heat transfer on the macro scale by either assuming local thermal equilibrium within an averaging volume or by formulating empirical models to describe the transfer rates. The latter is necessary as classically, both fluid–fluid and fluid–solid interfacial areas are unknown on the macro scale. And similiarly to mass transfer, we can use the thermodynamically-based approach of Hassanizadeh & Gray (1990; 1993b) which includes both fluid–fluid and fluid–solid interfacial areas in order to describe mass transfer in a physically-based way. We can (1) (2) wetting non−wetting mass transfer wetting non−wetting heat transfer Fig. 6. Mass transfer takes place across fluid–fluid interfaces (left hand side) and heat transfer across fluid–fluid as well as fluid–solid interfaces (right hand side) www.intechopen.com 14 14 Transfer Mass Transfer in Multiphase Systems andMass its Applications also perform a dimensional analysis and derive dimensionless numbers that help to decide whether kinetics of heat transfer needs to be accounted for or whether a local equilibrium model is sufficiently accurate on the macro scale. For more details on these issues, we refer to Niessner & Hassanizadeh (2009b). 5. Macro-scale example simulations For the numerical solution of the system of Eq.s (16) through (28), we use a fully-coupled vertex-centered finite element method (an in-house code) which not only conserves mass locally, but is also applicable to unstructured grids. For time discretization, a fully implicit Eulerian approach is used, see e.g. Bastian et al. (1997); Bastian & Helmig (1999). The nonlinear system is linearized using a damped inexact Newton-Raphson solver, and the linear system is subsequently solved using a Bi-Conjugate Gradient Stabilized method (known as BiCGStab method). Full upwinding is applied to the flux terms of the bulk phase equations, but in the interfacial area flux term, central weighting is used. 5.1 Evaporator As a simulation example, we consider a setup which is relevant in many industrial processes where a product needs to be concentrated (e.g. foods, chemicals, and salvage solvents) or dried through evaporation of water. The aqueous solution containing the desired product is fed into the evaporator mostly consisting of micro-channels and then passes a heat source. Heat converts the water in the solution into vapor and the vapor is subsequently removed from the solution. We model the heating and evaporation process through a setup as shown in Fig. 7. This means we consider a horizontal domain that is closed along the sides (top and bottom in the figure) and that is subjected to a gradient in wetting phase pressure from left to right in the undisturbed situation. This system is assumed to be at the following initial conditions: a temperature of 293 K, gas phase at atmospheric pressure, water saturation of 0.9, a corresponding capillary pressure based on the primary drainage curve, and mass fractions that correspond to the local chemical equilibrium conditions as prescribed by Henry’s Law and Raoult’s Law (Lüdecke & Lüdecke (2000)). The porous medium is heated with a rate of Qs in a square-shaped part of the domain, causing the evaporation of water (see Fig. 7). Note that the heat source heats up only the walls of the microchannels (the solid phase) and the heat is then transferred from the solid phase to the water phase. Sil = 0.9 pgi = 106875 Pa pci = pcdr (0.9) ai a Xl = Xl,s (pgi , Til ) w (p i , Ti ) Xwg i = Xg,s g g Tli = 293.15 K i Tg = 293.15 K Tsi = 293.15 K Sil = 0.9 pgi = 101325 Pa pci = pcdr (0.9) ai a Xl = Xl,s (pgi , Tli ) w Xwg i = Xg,s (pgi , Tni ) Tli = 293.15 K Tgi = 293.15 K Tsi = 293.15 K Qs Sil = 0.9 pgi = 101325 Pa pci = pcdr (0.9) a i i Xai l = Xl,s (pg , Tl ) w Xwg i = Xg,s (pgi , Tgi ) Tli = 293.15 K Tgi = 293.15 K Tsi = 293.15 K 0.5 m 0.7 m Fig. 7. Setup of the numerical example: water passes a heat source and is evaporated. www.intechopen.com 15 15 Massand andHeat HeatTransfer TransferDuring During Two-Phase Flow in Porous Media - Theory and Modeling Mass Two-Phase Flow in Porous Media - Theory and Modeling For comparison, the same setup is used for simulations using a classical two-phase flow model, where—in the absence of interfacial areas as parameters—local chemical and thermal equilibrium is assumed. This means that the heat source cannot be defined for the solid phase only; instead, the applied heat will instantaneously lead to a heating of all three phases. The distribution of water saturation and water–gas specific interfacial area are shown in Fig. 8 at the time of 17 seconds after the heat source is switched on. The saturation distribution given by the interfacial area-based model is compared to that of the classical model. Obviously, water saturation decreases in the heated region due to the evaporation of water. Downstream of the heated zone, water saturation increases indicating that in the colder regions, water condenses again. Due to the decrease in water saturation, gas–water interfacial areas are created. The classical model predicts a much lower decrease in water saturation in the heated region. Fig. 9 shows the mass fraction of air dissolved in the liquid phase after 17 seconds. There, also the equilibrium value (solubility limit) predicted by the interfacial area-based model is shown. Clearly, chemical non-equilibrium effects occur, but the classical model predicts approximately the same result as the equilibrium values in the interfacial area-based model. This is due to the fact that the classical two-phase flow approach always assumes local equilibrium and can only represent mass fractions corresponding to the equilibrium values. The analogous comparison is shown in Fig. 10 with respect to the mass fractions of vapor in the gas phase. Here, the mass fractions in the interfacial area-based model are very close to the equilibrium values, but larger differences to the classical model can be detected. Sl from interfacial area model Sw: 0.8 0.81 0.82 0.83 0.84 0.85 0.86 0.87 0.88 0.89 0.9 0.91 Sl from classical model S l Sw: alg from interfacial area model awn: a lg [1/m] 0.8 0.81 0.82 0.83 0.84 0.85 0.86 0.87 0.88 0.89 0.9 0.91 380 400 420 440 460 480 500 520 540 560 580 Fig. 8. Water saturation and water–gas specific interfacial area after 17s. a Xl from interfacial area model a a Xl,s from interfacial area model Xl from classical model a Xsw2 2.36E-05 2.34E-05 2.32E-05 2.3E-05 2.28E-05 2.26E-05 2.24E-05 2.22E-05 2.2E-05 2.18E-05 2.16E-05 2.14E-05 Xl 2.36E.6 2.24E−6 Fig. 9. Mass fraction of air in the liquid phase after 17s. Left: results using the interfacial area-based model, middle: equilibrium values given by the interfacial area-based model, right: results given by the classical model. www.intechopen.com 16 16 Transfer Mass Transfer in Multiphase Systems andMass its Applications w Xw g from interfacial area model w Xg,s from interfacial area model Xg from classical model w X g [−] Xsn1 XWG 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 Fig. 10. Mass fractions of vapor in the gas phase after 17s. Left: results using the interfacial area-based model, middle: equilibrium values given by the interfacial area-based model, right: results given by the classical model. Fig. 11 shows the temperatures of the three phases (liquid l, gas g, solid s) after 17s using the interfacial area-based model and the classical model. It can be seen that a lower temperature rise is predicted by the classical model than by the interfacial area-based model. T l from interfacial area model T g from interfacial area model T s from interfacial area model T from classical model T[K]Te Tn 375 370 365 360 355 350 345 340 335 330 325 320 315 310 305 300 295 375 370 365 360 355 350 345 340 335 330 325 320 315 310 305 300 295 Fig. 11. Temperatures of the phases after 17s using the interfacial area-based model (three pictures on left) and the classical model (right picture). Fig. 12 shows the temperature differences between the phases using the interfacial area-based model. We find that there are differences of up to 8 K between the phases. The classical two-phase model assumes local thermal equilibrium, i.e. Tw = Tn = Ts . In reality, however, the heat exchange between the phases is restricted by the respective interfacial areas and the heat equalization does not take place instantaneously. Tl − Tg T[K] dTwTn -0.5 -1 -1.5 -2 -2.5 -3 -3.5 -4 -4.5 -5 -5.5 -6 -6.5 -7 -7.5 -8 Tg − Ts T[K] dTnTs 0 -0.2 -0.4 -0.6 -0.8 -1 -1.2 -1.4 -1.6 -1.8 -2 -2.2 -2.4 -2.6 -2.8 -3 -3.2 -3.4 Fig. 12. Temperatures differences between wetting and non-wetting phase (left hand side) and between non-wetting and solid phase (right hand side) after 17s. www.intechopen.com 17 17 Massand andHeat HeatTransfer TransferDuring During Two-Phase Flow in Porous Media - Theory and Modeling Mass Two-Phase Flow in Porous Media - Theory and Modeling 5.2 Drying of a porous medium As a second example, we consider the drying of an initially almost water-saturated porous medium through injection of hot dry air (50 ◦ C). This process is relevant in the textile, construction, and paper industries as well as in medical applications. The setup is shown in Fig. 13. For comparison, this setup is also simulated using the classical model. Note that in the classical model, due to the assumption of local chemical and thermal equilibrium, it is impossible to apply a source of hot dry air. Instead, the air supplied to the system instantaneously redistributes among the phases in order to yield equilibrium composition. The temperature of the air source will instantaneously heat up all three phases. Sil = 0.9 pgi = 101475 Pa pci = pcdr (0.9) ai a Xl = Xg,s (pgi , Til ) w (p i , Ti ) Xwg i = Xg,s g g Tli = 293 K Tgi = 293 K Tsi = 293 K Sil = 0.9 pgi = 101325 Pa pci = pcdr (0.9) a i i Xai l = Xl,s (pg , Tl ) w (pi , Ti ) Xwg i = Xg,s g g Tli = 293 K Tgi = 293 K Tsi = 293 K a Sil = 0.9 Qn pgi = 101325 Pa T = 333 K pci = pcdr (0.9) ai a i i Xl = Xl,s (pg, Tl ) w i , Ti ) Xwi g = Xg,s (pg g Tli = 293 K i Tg = 293 K Tsi = 293 K 0.5 m 0.7 m Fig. 13. Setup of the numerical example: drying of a porous medium through injection of warm dry air. Fig. 14 shows the water saturation and the specific gas–water interfacial area after 12 seconds. The water saturation decreases due to the gas injection and interfaces are produced. The saturation distribution is different if the classical model is used. This may be due to the fact that the source term needs to be specified differently for the two models (see the above comments on the problem description). Sl from interfacial area model Sl from classical model Sw 0.89 0.88 0.87 0.86 0.85 0.84 0.83 0.82 0.81 0.8 0.79 0.78 0.77 0.76 0.75 0.74 0.73 0.72 SSw l 0.89 0.88 0.87 0.86 0.85 0.84 0.83 0.82 0.81 0.8 0.79 0.78 0.77 0.76 0.75 0.74 0.73 0.72 alg from interfacial area model a lg awn[1/m] 600 580 560 540 520 500 480 460 440 420 Fig. 14. Water saturation (using both interfacial area-based and classical model) and specific fluid–fluid interfacial area using the interfacial area-based model after 12s. In Fig. 15, the mass fraction of air disolved in the water phase is shown after 12s. The actual mass fraction distribution using the interfacial-area-based approach is shown in the left picture. The mass fraction corresponding to local chemical equilibrium is shown in the middle figure. For comparison, the mass fraction distribution resulting from the classical model is shown in the right figure. Obviously, significant deviations from equilibrium can be detected. This implies that chemical non-equilibrium is very important in this example. The www.intechopen.com 18 18 Transfer Mass Transfer in Multiphase Systems andMass its Applications a a a Xl,s from interfacial area model Xl from interfacial area model Xl from classical model a XXAW l XAW 2.348E-05 2.347E-05 2.346E-05 2.345E-05 2.344E-05 2.343E-05 2.342E-05 2.341E-05 2.348E-05 2.347E-05 2.346E-05 2.345E-05 2.344E-05 2.343E-05 2.342E-05 2.341E-05 Fig. 15. Mass fractions of air in water. Left: interfacial-area-based model, actual mass fractions; middle: equilibrium mass fractions. Right: classical model. equilibrium mass fractions of the interfacial area-based model are also very different from that predicted by the classical model, probably due to the differently specified source. Fig. 16 shows the same for water vapor in the gas phase. Here, the deviation from chemical equilibrium is also significant, but the equilibrium mass fractions using the interfacial area-based model and the classical model are very similar. Xw g from interfacial area model Xwg,s from interfacial area model w Xg from classical model w XWG XXWG g [−] 0.0175 0.017 0.0165 0.016 0.0155 0.015 0.0175 0.017 0.0165 0.016 0.0155 0.015 Fig. 16. Mass fractions of vapor in the gas phase. Left: interfacial-area-based model, actual mass fractions; middle: equilibrium mass fractions. Right: classical model. In Fig. 17, the temperatures of the three phases (liquid l, gas g, and solid phase s) resulting from the interfacial area-based model are shown and compared to the temperature given by the classical model. Unlike the mass fractions, the temperatures are not very far from equilibrium (maximum difference in phase temperatures is approximately 0.17 K, see also Fig. 18). An interesting aspect is that the temperature difference is lower in the middle of the injection zone than in the surrounding area. This is due to the fact that specific interfacial area is at a maximum in this middle part leading to higher heat transfer rates in this region and phase temperature closer to each other and thus, closer to thermal equilibrium. 6. Summary and conclusions In this chapter, the issue of interphase mass transfer during two-phase flow in a porous medium has been discussed. Starting from pore-scale considerations, the classical approaches for describing mass transfer have been presented which—due to the absence of interfacial area as a parameter—either assume local equilibrium within an averaging volume or use empirical approaches to describe the kinetics. www.intechopen.com 19 19 Massand andHeat HeatTransfer TransferDuring During Two-Phase Flow in Porous Media - Theory and Modeling Mass Two-Phase Flow in Porous Media - Theory and Modeling T l from interfacial area model T g from interfacial area model T s from interfacial area model T from classical model T[K] Te Ts 296.4 296.2 296 295.8 295.6 295.4 295.2 295 294.8 294.6 294.4 294.2 294 293.8 293.6 293.4 293.2 296.6 296.4 296.2 296 295.8 295.6 295.4 295.2 295 294.8 294.6 294.4 294.2 294 293.8 293.6 293.4 Fig. 17. Temperatures of the phases using the interfacial area-based model (three pictures on left hand side) and the classical model (right hand side picture). Tl − Tg Tg − Ts dTnTs T[K] T[K] dTwTn 0 -0.01 -0.02 -0.03 -0.04 -0.05 -0.06 -0.07 -0.08 -0.09 -0.1 -0.11 -0.12 -0.13 -0.14 -0.15 -0.16 -0.17 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Fig. 18. Temperature differences between the phases. As an alternative, a thermodynamically-based model was presented which explicitly accounts for the presence of interfaces and describes their evolution in space and time. Due to the knowledge of interfacial area, kinetic interface mass transfer can be modeled in a physically-based way. In order to decide whether kinetics of mass transfer needs to be accounted for or whether an equilibrium model would give sufficiently good results, a dimensional analysis was carried through. Also, the concept was extended to kinetic interphase heat transfer where in addition to fluid–fluid interfaces, fluid–solid interfaces are important. Two examples have illustrated the issues presented: in our results, we could observe that in the drying example, chemical non-equilibrium is significant. In the evaporator example, contrarily, thermal non-equilibrium is very pronounced. In order to advance the description of real life systems, such as those described in Sec. 1.1, an important future step would be to apply the presented model concept to practical applications and to verify the results by comparison to experimental data. 7. Acknowledgements We thank Benjamin Ahrenholz for providing the interfacial - area - capillary pressure saturation relationships from Lattice - Boltzman simulations that entered the numerical simulations shown in this chapter. 8. References Bastian, P., Birken, K., Johannsen, K., Lang, S., Eckstein, K., Neuss, N., Rentz-Reichert, H. & Wieners, C. (1997). UG - A Flexible Software Toolbox for Solving Partial Differential Equations, Computing and Visualization in Science, 1(1):27–40. Bastian, P. & Helmig, R. (1999). Efficient Fully-Coupled Solution Techniques for Two Phase Flow in Porous Media. Parallel Multigrid Solution and Large Scale Computations., www.intechopen.com 20 20 Transfer Mass Transfer in Multiphase Systems andMass its Applications Advances in Water Resources 23: 199–216. Bowen, R. (1982). Compressible Porous Media Models by Use of the Theory of Mixtures, International Journal of Engineering Science 20(6): 697–735. Brusseau, M., Popovicova, J. & Silva, J. (1997). Characterizing gas–water interfacial and bulk-water partitioning for gas phase transport of organic contaminants in unsaturated porous media, Environmental Sciences Technology 31: 1645–1649. Chen, D., Pyrak-Nolte, L., Griffin, J. & Giordano, N. (2007). Measurement of interfacial area per volume for drainage and imbibition, Water Resources Research 43(12). Chen, L. & Kibbey, T. (2006). Measurement of air–water interfacial area for multiple hysteretic drainage curves in an unsaturated fine sand, Langmuir 22: 6674–6880. Culligan, K., Wildenschild, D., Christensen, B., Gray, W., Rivers, M. & Tompson, A. (2004). Interfacial area measurements for unsaturated flow through a porous medium, Water Resources Research 40: 1–12. Falta, R. W. (2000). Numerical modeling of kinetic interphase mass transfer during air sparging using a dual-media approach, Water Resources Research 36(12): 3391–3400. Falta, R. W. (2003). Modeling sub-grid-block-scale dense nonaqueous phase liquid (DNAPL) pool dissolution using a dual-domain approach, Water Resources Research 39(12). Gray, W. & Hassanizadeh, S. (1989). Averaging theorems and averaged equations for transport of interface properties in multiphase systems, International Journal of Multi-Phase Flow 15: 81–95. Gray, W. & Hassanizadeh, S. (1998). Macroscale continuum mechanics for multiphase porous-media flow including phases, interfaces, common lines, and common points, Advances in Water Resources 21: 261–281. Gray, W. & Miller, C. (2005). Thermodynamically Constrained Averaging Theory Approach for Modeling of Flow in Porous Media: 1. Motivation and Overview, Advances in Water Resources 28(2): 161–180. Hassanizadeh, S. M. & Gray, W. G. (1979). General Conservation Equations for Multi-Phase Systems: 2. Mass, Momenta, Energy, and Entropy Equations, Advances in Water Resources 2: 191–203. Hassanizadeh, S. M. & Gray, W. G. (1980). General Conservation Equations for Multi-Phase Systems: 3. Constitutive Theory for Porous Media Flow, Advances in Water Resources 3: 25–40. Hassanizadeh, S. M. & Gray, W. G. (1990). Mechanics and Thermodynamics of Multiphase Flow in Porous Media Including Interphase Boundaries, Advances in Water Resources 13(4): 169–186. Hassanizadeh, S. M. & Gray, W. G. (1993a). Thermodynamic Basis of Capillary Pressure in Porous Media, Water Resources Research 29(10): 3389 – 3405. Hassanizadeh, S. M. & Gray, W. G. (1993b). Toward an improved description of the physics of two-phase flow, Advances in Water Resources 16(1): 53–67. Held, R. & Celia, M. (2001). Modeling support of functional relationships between capillary pressure, saturation, interfacial area and common lines, Advances in Water Resources 24: 325–343. Imhoff, P., Jaffe, P. & Pinder, G. (1994). An experimental study of complete dissolution of a nonaqueous phase liquid in saturated porous media, Water Resources Research 30(2): 307–320. IPCC (2005). Carbon Dioxide Capture and Storage. Special Report of the Intergovernmental Panel on Climate Change, Cambridge University Press. www.intechopen.com Massand andHeat HeatTransfer TransferDuring During Two-Phase Flow in Porous Media - Theory and Modeling Mass Two-Phase Flow in Porous Media - Theory and Modeling 21 21 Jackson, A., Miller, C. & Gray, W. (2009). Thermodynamically constrained averaging theory approach for modeling flow and transport phenomena in porous medium systems: 6. two-fluid-phase flow, Advances in Water Resources 32(6): 779–795. Joekar-Niasar, V., Hassanizadeh, S. M. & Leijnse, A. (2008). Insights into the relationship among capillary pressure, saturation, interfacial area and relative permeability using pore-scale network modeling, Transport in Porous Media 74: 201–219. Joekar-Niasar, V., Hassanizadeh, S. M., Pyrak-Nolte, L. J. & Berentsen, C. (2009). Simulating drainage and imbibition experiments in a high-porosity micro-model using an unstructured pore-network model, Water Resources Research 45(W02430, doi:10.1029/2007WR006641). Kalaydjian, F. (1987). A Macroscopic Description of Multiphase Flow in Porous Media Involving Spacetime Evolution of Fluid/Fluid Interface, Transport in Porous Media 2: 537 – 552. Lüdecke, C. & Lüdecke, D. (2000). Thermodynamik, Springer, Berlin. Marle, C.-M. (1981). From the pore scale to the macroscopic scale: Equations governing multiphase fluid flow through porous media, Proceedings of Euromech 143, pp. 57–61. Delft, Verruijt, A. and Barends, F. B. J. (eds.). Mayer, A. & Hassanizadeh, S. (2005). Soil and Groundwater Contamination: Nonaqueous Phase Liquids, American Geophysical Union. Miller, C., Poirier-McNeill, M. & Mayer, A. (1990). Dissolution of trapped nonaqueous phase liquids: Mass transfer characteristics, Water Resources Research 21(2): 77–120. Niessner, J. & Hassanizadeh, S. (2008). A Model for Two-Phase Flow in Porous Media Including Fluid–Fluid Interfacial Area, Water Resources Research . 44, W08439, doi:10.1029/2007WR006721. Niessner, J. & Hassanizadeh, S. (2009a). Modeling kinetic interphase mass transfer for two-phase flow in porous media including fluid–fluid interfacial area, Transport in Porous Media . doi:10.1007/s11242-009-9358-5. Niessner, J. & Hassanizadeh, S. (2009b). Non-equilibrium interphase heat and mass transfer during two-phase flow in porous media—theoretical considerations and modeling, Advances in Water Resources 32: 1756–1766. Porter, M., Schaap, M. & Wildenschild, D. (2009). Lattice-boltzmann simulations of the capillary pressure-saturation-interfacial area relationship for porous media, Advances in Water Resources 32(11): 1632–1640. Powers, S., Abriola, L. & Weber, W. (1992). An experimental investigation of nonaqueous phase liquid dissolution in saturated subsurface systems: steady state mass transfer rates, Water Resources Research 28: 2691–2706. Powers, S., Abriola, L. & Weber, W. (1994). An experimental investigation of nonaqueous phase liquid dissolution in saturated subsurface systems: transient mass transfer rates, Water Resources Research 30(2): 321–332. Reeves, P. & Celia, M. (1996). A functional relationship between capillary pressure, saturation, and interfacial area as revealed by a pore-scale network model, Water Resources Research 32(8): 2345–2358. Schaefer, C., DiCarlo, D. & Blunt, M. (2000). Experimental measurements of air–water interfacial area during gravity drainage and secondary imbibition in porous media, Water Resources Research 36: 885–890. van Antwerp, D., Falta, R. & Gierke, J. (2008). Numerical Simulation of Field-Scale Contaminant Mass Transfer during Air Sparging, Vadose Zone Journal 7: 294–304. www.intechopen.com 22 22 Transfer Mass Transfer in Multiphase Systems andMass its Applications Wildenschild, D., Hopmans, J., Vaz, C., Rivers, M. & Rikard, D. (2002). Using X-ray computed tomography in hydrology. Systems, resolutions, and limitations, Journal of Hydrology 267: 285–297. Zhang, H. & Schwartz, F. (2000). Simulating the in situ oxidative treatment of chlorinated compounds by potassium permanganate, Water Resources Research 36(10): 3031–3042. www.intechopen.com Mass Transfer in Multiphase Systems and its Applications Edited by Prof. Mohamed El-Amin ISBN 978-953-307-215-9 Hard cover, 780 pages Publisher InTech Published online 11, February, 2011 Published in print edition February, 2011 This book covers a number of developing topics in mass transfer processes in multiphase systems for a variety of applications. The book effectively blends theoretical, numerical, modeling and experimental aspects of mass transfer in multiphase systems that are usually encountered in many research areas such as chemical, reactor, environmental and petroleum engineering. From biological and chemical reactors to paper and wood industry and all the way to thin film, the 31 chapters of this book serve as an important reference for any researcher or engineer working in the field of mass transfer and related topics. How to reference In order to correctly reference this scholarly work, feel free to copy and paste the following: Jennifer Niessner and S. Majid Hassanizadeh (2011). Mass and Heat Transfer During Two-Phase Flow in Porous Media - Theory and Modeling, Mass Transfer in Multiphase Systems and its Applications, Prof. Mohamed El-Amin (Ed.), ISBN: 978-953-307-215-9, InTech, Available from: http://www.intechopen.com/books/mass-transfer-in-multiphase-systems-and-its-applications/mass-and-heattransfer-during-two-phase-flow-in-porous-media-theory-and-modeling InTech Europe InTech China University Campus STeP Ri Slavka Krautzeka 83/A 51000 Rijeka, Croatia Phone: +385 (51) 770 447 Fax: +385 (51) 686 166 www.intechopen.com Unit 405, Office Block, Hotel Equatorial Shanghai No.65, Yan An Road (West), Shanghai, 200040, China Phone: +86-21-62489820 Fax: +86-21-62489821 © 2011 The Author(s). Licensee IntechOpen. 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https://ph.pollub.pl/index.php/acs/article/download/3230/2796
English
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AN EFFECTIVE METAHEURISTIC FOR TOURIST TRIP PLANNING IN PUBLIC TRANSPORT NETWORKS
Applied Computer Science
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Submitted: 2018-05-14 Revised: 2018-06-03 Accepted: 2018-06-21 Submitted: 2018-05-14 Revised: 2018-06-03 Accepted: 2018-06-21 Applied Computer Science, vol. 14, no. 2, pp. 5–19 doi:10.23743/acs-2018-09 time-dependent orienteering problem with time-windows, evolutionary algorithm, public transport network, tourist trip planning Krzysztof OSTROWSKI* * Faculty of Computer Science, Białystok University of Technology, Wiejska 45A, 15-001 Białystok, Poland, k.ostrowski@pb.edu.pl Abstract ract The Time-Dependent Orienteering Problem with Time Windows (TDOPTW) is a combinatorial optimization problem defined on graphs. Its real life applications are particularly associated with tourist trip planning in trans- port networks, where travel time between two points depends on the moment of travel start. In the paper an effective TDOPTW solution (evolutionary algorithm with local search operators) was presented and applied to gen- erate attractive tours in real public transport networks of Białystok and Athens. The method achieved very high-quality solutions in a short execution time. 1. INTRODUCTION The Time-Dependent Orienteering Problem with Time Windows (TDOPTW) belongs to the Orienteering Problem (OP) family. The classic OP is defined on a weighted graph with nonnegative profits associated to vertices and nonnegative costs associated to edges. The goal of the OP is to find a path between given two vertices that maximizes total profit of visited vertices and its total cost does not exceed a given limit. The OP solution does not have to contain all vertices (usually it is impossible because of cost limit) and each vertex can be visited only once. The Time-Dependent Orienteering Problem with Time Windows (TDOPTW) is a generalization of the OP defined for time-dependent graphs. Edge costs are identified with travel times, which depend on the moment of travel start (edge 5 weights are time-dependent functions). In addition each vertex has a visit time and a time-window. Arriving too early means waiting for the time-window to open while arriving too late makes it impossible to visit a given vertex. Transport networks are examples of time-dependent graphs are. Travel time between two points depends on traffic intensity (i.e. longer during rush hours) and timetables (in case of public transport networks). Problems from the TDOPTW family have many practical applications including tourist trip planning (Garcia, Vansteenwegen, Arbelaitz, Souffriau & Linaza, 2013) and transport logistics. In tourist trip planning each tourist attraction (point of interest – POI) has some profit (i.e. dependent on its popularity), visit time and opening hours (time- window). Finding an attractive tour of a limited duration in a time-dependent transport network is equivalent to solving the TDOPTW. The paper is organized as follows. In section 2 a mathematical formulation of the TDOPTW is given. In section 3 a literature review is presented. Section 4 describes public transport network as a time-dependent graph. Section 5 describes methods applied. In section 6 experimental results are given. Section 7 is the con- clusion of the paper. 2. PROBLEM DEFINITION Let G = (V, E) be a directed, weighted graph. Each vertex i has a nonnegative profit pi, a nonnegative visit time τi and a time-window <oi, ci>. Travel time between vertices i and j (i, j ∈ V ) is a nonnegative function wij(t) dependent on the moment of travel start t. The goal of the TDOPTW is to find a path from vertex s to vertex e starting at time t0 which maximizes total profit of visited vertices without exceeding total travel time (Tmax) and without violating time- windows of visited vertices. TDOPTW can be formulated as a Mixed Integer Programming (MIP) problem. Let’s introduce three additional variables. Variable xij is 1 if a path contains a direct travel from vertex i to vertex j and 0 otherwise. Let tai and tdi be a time of arrival at vertex i and a time of departure from it – these functions are defined only for vertices included in the path. It’s assumed that vertices s and e have no profit, zero visit time and no time-window. 2. PROBLEM DEFINITION The purpose of the TDOPTW is to maximize formula 1 without violating constraints 2–8: , max i ij i j V p x    (1) 1 sj ie j V i V x x       (2) (1) 1 sj ie j V i V x x       (2) (2) 6 6 \{ , } 1 ik kj k V s e i V j V x x               (3) 0 s td t  (4) (5) \{ , } ( max( , ) ) i i i i i V s e td ta o      (6) 0 max e ta t T   (7) \{ , } ( ) i i i V s e ta c    (8)   , 1 ( ) ij j i ij i i j V x ta td w td      \{ , } ( max( , ) ) i i i i i V s e td ta o      (8) Equation 2 guarantees that the solution starts at vertex s and ends at vertex e while formula 3 means that each vertex can be visited only once. Formula 4 forces travel to start at time t0 while formulas 5 and 6 defines a relation between arrival and departure times at subsequent vertices (based on travel times, visit times and time-windows). Assuming that travel times between different vertices are positive, formulas 4–6 guarantee that there are no sub-cycles in the path. Constraints 7 and 8 are associated with maximum travel time and time-windows. 3. LITERATURE REVIEW Problems from the Orienteering Problem family are NP-hard (Golden, Levy, Vohra, 1987) and exact algorithms can be very time-consuming for larger graphs. For this reason most papers are devoted to metaheuristics. Various approaches for the OP were based i.a. on greedy and randomized construction of solutions (Campos, Marti, Sanchez-Oro & Duarte, 2014), local search methods (Chao, Golden & Wasil, 1996; Vensteenwegen, Souffriau, Vanden Berghe & Oudheusden, 2009), tabu search (Gendreau, Laporte & Semet, 1998), ant-colony optimization (Schilde, Doerner, Hartl & Kiechle, 2009) and genetic algorithms (Tasgetiren, 2001). g g g Most papers about Time-Dependent versions of the Orienteering Problem were published in recent years and emphasize practical aspects of the problem, especially tourist trip planning in transport networks. Garcia et al. (2013) presented the first paper describing its application in POI and public transport network of San Sebastian. To solve the problem the authors proposed Iterated Local Search method (ILS). However, they performed computations on average daily travel times and assumed periodicity of public transport timetables. 7 Gavalas et al. (2015) proposed an approach which uses real time-dependent travel times in a transport network of Athens. The authors introduced two fast heuristics (TD_CSCR and TDSlCSCR), which based on ILS and vertex clustering, and made comparisons of a few methods. Verbeeck at al. (2014) developed new benchmark instances for the TDOP, which model street traffic. The authors proposed an ant-colony approach, which achieved high quality results in a short execution time. Gunawan et al. (2014) modified Verbeeck's benchmarks (discretization of time) and compared a few approaches (adaptive ILS proved to be the most effective of them). The author's previous papers were devoted to metaheuristics for problems from the OP family. Methods developed by the author (composition of evolutionary algorithms and local search heuristics) proved successful on the OP (Ostrowski, Karbowska-Chilinska, Koszelew & Zabielski, 2017; Ostrowski, 2015) as well as TDOP benchmark instances (Ostrowski, 2017). The algorithms achieved results close to optimal and outperformed other methods: GRASP (Campos et al, 2014), GLS (Vensteenwegen et al., 2009), ACS (Verbeeck at al 2014) and Adaptive ILS (Gunawan et al, 2014). The purpose of this work was to adapt the TDOP algorithm to the TDOPTW, apply it for tourist trip planning in real public transport and POI network and verify quality of its solutions. 4. PUBLIC TRANSPORT AND POI NETWORK AS A TIME-DEPENDENT GRAPH It’s assumed that a tourist uses means of public transport (buses in the city of Białystok) when travelling between attractions (POIs). Travel time between POIs depends on bus timetables. For this reason a network of POIs connected by public transportation is a time-dependent graph. Here are assumptions made by the author: y 1. A travel between two POIs can consist of two kinds of edges: walk links and bus connections. 2. Walk links have a limited length (Dmax) and walk times are determined by assuming that walking speed is 3 km/h. A tourist can walk directly between POIs, between POIs and bus stops and between bus stops (during bus transfers). 3. During a travel between a pair of POIs a tourist can use up to k bus transfers (k+1 bus connections). 4. To compensate for deviations of bus arrival times from timetables a min- imum waiting time at a bus stop (3 minutes) was introduced. 5. Each graph weight wij(t) is the duration of the shortest travel from POI i to POI j starting at time t. To compute weights it’s necessary to execute shortest path algorithm in multimodal time-dependent graph. 8 6. Time is discrete (resolution of 1 minute), which is consistent with time- tables. For this reason there are 1440n2 graph weights (n is number of POIs and there are 1440 minutes in a day). Fig. 1. An exemplary travel between two POIs Fig. 1. An exemplary travel between two POIs In fig. 1. there is an exemplary travel between two POIs consisting of 3 bus connections (2 transfers) and 3 walk links. A tourist leaves POI 1, walks to bus stop B1 and gets on a bus (line A). He gets off at bus stop B2 and waits there for another bus (line B). Afterwards he goes by bus B to bus stop B4. From there he walks to a nearby bus stop B5, where he gets onto another bus (line C) and travels to bus stop B7. From there he walks to his destination (POI 2). Computation of such shortest paths is necessary to get time-dependent weights, which will be used by the metaheuristic solving the Time-Dependent Orienteering Problem. 5. METHOD DESCRIPTION To realize tourist trip planning in a public transport network of Białystok two tasks should be done: 1. Computation of time-dependent weights based on bus timetables and POIs location. 2. Execution of the TDOP algorithm, which operates on time-dependent weights and generates attractive tours. 9 Shortest travels from a given POI at a given start time to all other POIs In order to compute all weights efficiently the author decided to use modified Ford-Bellman algorithm and optimize some precomputation steps. The basic Ford-Bellman procedure computes shortest travels starting at time t0 from a given start POI s to all other POIs and bus stops. The algorithm has k+1 main iterations (k – number of bus transfers). It enables to efficiently compute shortest paths consisted of a limited number of bus connections. During the first iteration bus connections starting at bus stops not farther than max. walk distance (Dmax) from s are considered. Only earliest possible buses of given lines are considered. Afterwards all possible bus stops, where a tourist can get off the bus (exit bus stops), are analysed. From there destination POIs (within walking distance from exit bus stops) are checked. In this way all shortest travel times (consisting of one transport connection) are computed. Analogically the second iteration computes all shortest travels consisted of at most two transport connections (one bus transfer): when analysing an exit bus stop the algorithm searches for other bus connections leaving from the current bus stop and from other neighbouring bus stops (transfer step). The same steps are performed for subsequent iterations. For optimization purposes the algorithm only analyses those bus stops, for which travel time improved in the previous iteration. 5.1. Precomputation of weights During its execution the TDOP metaheuristic refers to graph weights millions of times. Computing shortest path in a time-dependent network so many times can cause an additional time overhead. For this reason the author decided to precompute and save all 1440n2 weights. Precomputed weights are stored in a 3-dimensional array. Thanks to the precomputation step the TDOP algorithm has access to all weights in constant time. Shortest travels between all POIs for all start times To compute all possible weights for all 1440 start times the above procedures are executed for all starting POIs. Thanks to the described optimization precomputation time was significantly reduced. Shortest travels from a given POI for all start times The purpose of precomputation is to compute shortest travels for all 1440 start times (minutes) in a day. Instead of executing the same shortest path algorithm (described above) 1440 times an optimization can be done. It arises from a simple observation (known as FIFO property): t + wij(t) ≤ (t+1) + wij(t+1). The formula means that earlier travel start implies not later travel finish – in the most pessimistic case travel starting at time t will use the same bus connections as travel starting at time t+1 (the only difference is one more minute of waiting at the first bus stop). Thanks to this property shortest travels for consecutive start times can be computed much faster. When computing shortest travels starting at time t the algorithm uses shortest travel times previously computed for start time t+1. The algorithm considers only those bus connections, which were impossible 10 to catch one minute later. This significantly reduces precomputation time, especially when frequency of bus connections is less than a minute (which is common in public transport networks – see fig. 2). In the below figure there is an example of time-dependent arrival times: the function is nondecreasing (and constant in intervals). Inside these intervals an equality t + wij(t) = (t+1) + wij(t+1) holds, which usually means that the same set of connections is used and computation time can be reduced. What is more, the FIFO property in time-dependent networks implies existence of polynomial time shortest-paths algorithms (Dean, 2004), which made it possible to develop fast precomputation procedure. Fig. 2. Arrival time at POI j as a function of departure time from POI i Fig. 2. Arrival time at POI j as a function of departure time from POI i 5.2. TDOPTW metaheuristic for tourist trip planning To solve the trip planning problem the author used an evolutionary algorithm, which is based on the method solving the TDOP (Ostrowski, 2017). The author adapted the method to the presence of time-windows. It uses both random and local search operators, 2-point heuristic crossover, disturb operator and deter- ministic crowding as selection mechanism. What is more, infeasible solutions (too long paths) are present in the population (penalized by the fitness function). A path representation is used – subsequent genes in a chromosome correspond to successive vertices in a path. After a random initialization the algorithm continues computations until a given generations limit (Ng) is achieved or there was no solution improvement in the last Cg generations. 11 Selection After crossover children compete with their own parents for places in the pop- ulation – survivor selection in the form of deterministic crowding (Mahfoud, 1992). Distance metric used bases on the length of longest common subsequence of two solutions. This form of selection preserve population diversity for longer, which allows a more effective search of the solution space (Ostrowski, 2015). Evaluation Fitness of a feasible solution s is equal to its profit. Otherwise it is described by the formula: fitness(s) = p(s)[Tmax/t(s)]k, where p(s) and t(s) are profit and travel time of solution s. Parameter k (penalty severity) is initially equal to 1 but it is adaptive and increases if more than α percent of paths in the population are infeasible. Crossover Parent selection is random. Crossover probability determines the fraction of population chosen for reproduction (selected individuals arranged in random pairs). The algorithm uses specialized 2-point heuristic crossover. Crossover procedure exchanges one pair of path fragments between consecutive common points of both parents. In fig. 3. an example of crossover is illustrated. There are three possible crossings (varying in exchanged fragments). Heuristic crossover chooses the option which maximizes fitness of the better child. Mutation Mutation probability determines the fraction of individuals which are selected (randomly) for mutation. Initially, selected paths undergo 2-opt procedure, which tries to reverse a path fragment in order to reduce total travel time as much as possible. Afterwards a vertex insertion or vertex deletion is carried out (each with a probability of 0.5). Both insert and delete operators have two versions: local search and random. Local search insert from all options of inserting a new vertex chooses the one that maximizes profit to travel time increase ratio. Analogically delete searches for a vertex which minimizes profit to travel time reduction ratio. Random versions choose vertices arbitrary but insertion place is chosen in order to minimize travel time increase. Probability of local search during mutation is determined by a parameter (heuristic coefficient). 12 Fig. 3. An example of crossover Fig. 3. An example of crossover Fig. 3. An example of crossover Time-Windows All operators used in the algorithm were modified in order to take into account time-windows. Given a POI with a time-window <o, c> and arrival time t, arriving too early (t<o) means that additional waiting time (o-t) was added to the tour duration. Arriving too late (t>c) made it impossible to visit a vertex and such cases weren’t allowed by the algorithm operators. Disturb Disturb procedure is another form of mutation, which applies bigger changes in individuals but is executed rarely. A small fraction of population (determined by disturb probability) is randomly chosen and a path fragment (no longer than 10 percent of vertices) is removed from each of them. Path fragment is chosen randomly or in a heuristic way (to minimize profit to travel time reduction ratio). 6. EXPERIMENTAL RESULTS Experiments were conducted on a computer with Intel Core i7 3.5 GHz processor and the algorithms were implemented in C++. First part of experiments was devoted to precomputation of travel times between POIs in public transport network of Białystok and in the second part the TDOPTW metaheuristic was applied for tourist trip planning in this network (using precomputed weights). 13 6.1. Precomputation and network properties Public transport and POI network of Białystok consists of 74 POIs (museums, palaces, churches etc), 37 bus lines and 693 bus stops. Thanks to optimizations (described in the previous section) precomputation time was only a few seconds. Shortest travel times between all pairs of POIs for all start times (1440 minutes in a day) were stored in a 3-dimensional array (occupying 18 MB of RAM). To find out about interesting features of the network, precomputation was executed many times for different values of parameters: maximal walk distance (Dmax) and maximal number of bus transfers (k). Tests were conducted for two Dmax values (0.3 and 0.6 km) and four k values (0, 1, 2, 3). In fig. 4. a dependency between percentage of connected POIs and pre- computation parameters is illustrated. It can be seen that large majority of POI pairs are connected when travel consists of at most one bus transfer (two transport connections) and there is no connectivity improvement for more than 2 bus transfers. Connection percentage improves for larger value of Dmax. Longer walk links enable to reach larger number of bus stops, which naturally implies more connection options. One can see that for shorter walk links connectivity is always less than 100 percent (regardless of number of bus transfers). This is due to the fact that a few POIs were farther than 0.3 km from nearest bus stop. In fig. 5. it can be seen that most of shortest travels between POIs are very simple (no bus transfer or one transfer) and almost no paths consist of more than 2 transfers. This is due to the fact that Białystok is a relatively compact city. Larger Dmax value influences paths simplicity for the same reason as it influenced connections percentage. Fig. 4. Percentage of connected POI pairs depending on Dmax and k Fig. 4. Percentage of connected POI pairs depending on Dmax and k Fig. 4. Percentage of connected POI pairs depending on Dmax and k 14 14 Fig. 5. Percentage of different types of shortest paths depending on Dmax Fig. 6. Histogram of travel times between POIs for different Dmax values (computed for daily hours 6:00–18:00). ig. 6. it can be seen that travel times of 20–40 minutes are most c 9 percent) and the majority of travels last less than an hour. In additio re short travels and less long travels when increasing Dmax. 6.2. Trip planning in Białystok The tested network included 74 POIs and 2 start/end points. For each attraction a profit, a visit time and a time-window (opening hours) were assigned (link to network: http://p.wi.pb.edu.pl/krzysztof-ostrowski/node/1252). Trips were 3, 6 and 9 hours long (Tmax) and started at 6:00, 9:00, 12:00 and 15:00 (t0). Time unit used in test files as well as during computations was a minute i.e. 9:00 is 540 and 4 hours are 240 minutes. There were two variants of trips: starting and ending in the city centre (s = e = 1) and in the western part of the city (s = e = 2). The author tested two methods: the TDOPTW metaheuristic (evolutionary algorithm with local search heuristics) as well as an exact algorithm (composition of branch-and-bound and dynamic programming developed by the author). Thanks to the exact algorithm optimal solutions are known (up to a few hours of computation time for longest trips) and it’s possible to access the quality of paths generated by the metaheuristic. p q y p g y Algorithm parameter values were derived from EVO100 in the author’s previous TDOP article (Ostrowski, 2017) with a small change: mh = 0.8 and ch = 1 instead of mh = 1 and ch = 0.8 (minor error in the article). For each test case the evolutionary algorithm was executed 30 times and average result was calculated. Gaps are given in percent and illustrate relative quality loss to optimal solutions. Execution times are given in seconds. The author’s metaheuristic is marked as EVO while OPT indicate profits of optimal tours (expressed as the sum of attractiveness of visited POIs). In tab. 1. results of trip planning are given (trips start and end in the city centre). One can see that EVO achieves optimal results in most cases and average gap is only 0.02 and 0.19 percent (for Dmax = 0.3 and 0.6 km). High-quality results are achieved in short execution times (0.3–1.4 s). It can be seen that optimal trips are a few percent better for larger value of Dmax. This is due to shorter travel times when using longer walk links (as described in the previous subsection), which enables to visit more POIs within a given time frame. Tab.1. 6.1. Precomputation and network properties It is ass e fact that for larger Dmax value travel times are generally shorter (m ctions are considered when searching for paths) – average daily trav nd 41 minutes (for Dmax 0.3 and 0.6 accordingly). Fig. 5. Percentage of different types of shortest paths depending on Dmax Fig. 5. Percentage of different types of shortest paths depending on Dmax Fig. 6. Histogram of travel times between POIs for different Dmax values (computed for daily hours 6:00–18:00). Fig. 6. Histogram of travel times between POIs for different Dmax values (computed for daily hours 6:00–18:00). In fig. 6. it can be seen that travel times of 20–40 minutes are most common (46–49 percent) and the majority of travels last less than an hour. In addition, there are more short travels and less long travels when increasing Dmax. It is associated with the fact that for larger Dmax value travel times are generally shorter (more bus connections are considered when searching for paths) – average daily travel time is 45 and 41 minutes (for Dmax 0.3 and 0.6 accordingly). In fig. 6. it can be seen that travel times of 20–40 minutes are most common (46–49 percent) and the majority of travels last less than an hour. In addition, there are more short travels and less long travels when increasing Dmax. It is associated with the fact that for larger Dmax value travel times are generally shorter (more bus connections are considered when searching for paths) – average daily travel time is 45 and 41 minutes (for Dmax 0.3 and 0.6 accordingly). 15 6.2. Trip planning in Białystok Trip planning results for s = e = 1 Dmax = 0.3 km Dmax = 0.6 km EVO EVO Tmax t0 Gap Time OPT Tmax t0 Gap Time OPT 3h 6:00 0.0 0.3 327 3 h 6:00 0.0 0.5 342 9:00 0.0 0.4 475 9:00 0.0 0.5 475 12:00 0.0 0.4 475 12:00 0.0 0.5 512 15:00 0.0 0.5 485 15:00 1.6 0.5 506 6 h 6:00 0.0 0.9 741 6 h 6:00 0.1 0.8 769 9:00 0.0 0.8 813 9:00 0.0 0.8 878 12:00 0.1 0.9 850 12:00 0.0 0.7 900 9 h 6:00 0.1 1.4 1089 9 h 6:00 0.0 1.2 1144 9:00 0.0 1.1 1178 9:00 0.0 1.2 1218 Average 0.02 0.75 – Average 0.19 0.75 – 16 In tab. 2. analogical results are presented for trips starting and ending in the western part of the city (s = e = 2). Optimal solutions were obtained by EVO for all but 2 test cases in short execution times. Trips quality is lower than it the previous table because most attractions are located in the city centre and additional time is needed to get there. In fig. 7. a trip generated by the algorithm is presented. It is short and all visited POIs are in the city centre so only one bus connection is needed. It worth noting that the algorithm usually chooses consecutive POIs which are close to each other in order to use the time budget effectively. For this reason travels between POIs found in solutions are usually short (only 5–15 minutes, compared to average of 40–45 minutes) and simple (a walk link or a single bus connection). Tab. 2. Trip planning results for s = e = 2 Dmax = 0.3 km Dmax = 0.6 km EVO EVO Tmax t0 Gap Time OPT Tmax t0 Gap Time OPT 3 h 6:00 0.0 0.3 226 3 h 6:00 0.0 0.4 226 9:00 0.0 0.4 338 9:00 0.0 0.4 350 12:00 0.0 0.4 338 12:00 0.0 0.4 338 15:00 0.0 0.4 358 15:00 0.0 0.4 375 6 h 6:00 0.0 0.7 659 6 h 6:00 0.0 0.6 677 9:00 0.0 0.7 708 9:00 0.5 0.7 721 12:00 0.0 0.8 786 12:00 0.0 0.7 805 9 h 6:00 0.0 1.1 996 9 h 6:00 0.1 1.2 1024 9:00 0.0 1.1 1125 9:00 0.0 1.0 1162 Average 0.0 0.65 – Average 0.07 0.65 – Tab. 2. 6.2. Trip planning in Białystok Trip planning results for s = e = 2 Dmax = 0.3 km Dmax = 0.6 km EVO EVO Tmax t0 Gap Time OPT Tmax t0 Gap Time OPT 3 h 6:00 0.0 0.3 226 3 h 6:00 0.0 0.4 226 9:00 0.0 0.4 338 9:00 0.0 0.4 350 12:00 0.0 0.4 338 12:00 0.0 0.4 338 15:00 0.0 0.4 358 15:00 0.0 0.4 375 6 h 6:00 0.0 0.7 659 6 h 6:00 0.0 0.6 677 9:00 0.0 0.7 708 9:00 0.5 0.7 721 12:00 0.0 0.8 786 12:00 0.0 0.7 805 9 h 6:00 0.0 1.1 996 9 h 6:00 0.1 1.2 1024 9:00 0.0 1.1 1125 9:00 0.0 1.0 1162 Average 0.0 0.65 – Average 0.07 0.65 – Fig. 7. A tour generated by the algorithm (Google Maps): walk links in red, bus connections in blue; icons: camera (POI), bus (bus stop), house (start/end), Tmax = 3h, t0 = 9:00. Tab. 2. Trip planning results for s = e = 2 Fig. 7. A tour generated by the algorithm (Google Maps): walk links in red, bus connections in blue; icons: camera (POI), bus (bus stop), house (start/end), Tmax = 3h, t0 = 9:00. Fig. 7. A tour generated by the algorithm (Google Maps): walk links in red, bus connections in blue; icons: camera (POI), bus (bus stop), house (start/end), Tmax = 3h, t0 = 9:00. 17 6.3. Trip planning in the city of Athens Additional tests were performed on public transport and POI network in Athens (tests created by Gavalas et al, 2015). The authors proposed 2000 different test cases (varying in topology and tourist preferences) and the presented results are average of all 2000 algorithm runs. The evolutionary algorithm was compared with the following heuristics: g 1. Time-dependent heuristics: TD_CSCR, TD_SlCSCR (Gavalas et al, 2015) and their version working on average travel times (AvgCSCR). 2. ILS algorithm working on average travel times (AvgILS, Garcia et al, 2013) and its time-dependent version (TD_ILS). 3. Exact algorithm implemented by the author (OPT). Compared methods were very fast (execution times of less than 0.1 s) and in order to achieve similar execution times the author tested another version of the evolu- tionary algorithm with reduced population size (EVO30). Population size and gen- eration parameters were scaled (Psize = 30, Ng = 1500, Cg = 150). In tab. 3. experimental results are presented. It can be seen that the proposed evolutionary algorithm (in both versions) achieves results very close to optimal. They are 0.6–2.0 percent better than the best of other metaheuristics (TD_SlCSCR and TD_CSCR). Gaps to other methods are much bigger (3.5–13.5 percent). It confirms effectiveness of the proposed method. Tab. 3. Trip planning results for the city of Athens (Tmax = 5h, t0 = 10:00) Method Score Gap Method Score Gap EVO100 344.57 0.02 Avg_CSCR 332.01 3.7 EVO30 344.34 0.1 TD_ILS 326.28 5.3 TD_SlCSCR 342.06 0.7 Avg_ILS 298.53 13.4 TD_CSCR 337.78 2.0 OPT 344.6 – REFERENCES Campos, V., Marti, R., Sanchez-Oro, J., & Duarte, A. (2014). Grasp with Path Relinking for the Orienteering Problem. Journal of the Oper. Res. Society, 65(12), 1800–1813. doi:10.1057/jors.2013.156 Chao, I., Golden, B., & Wasil, E. (1996). Theory and methodology - a fast and effective heuristic for the orienteering problem. European Journal of Operational Research, 88(3), 475–489. doi:10.1016/0377-2217(95)00035-6 Dean, B.C. (2004). Shortest paths in FIFO time-dependent networks: theory and algorithms. Technical report, MIT Department of Computer Science. Garcia, A., Vansteenwegen, P., Arbelaitz, O., Souffriau, W., & Linaza, M. T. (2013). Integrating public transportation in personalised electronic tourist guides. Computers and Operations Research, 40(3), 758–774. doi:10.1016/j.cor.2011.03.020 Gavalas, D., Konstantopoulos, C., Mastakas, K., Pantziou, G., & Vathis, N. (2015). Heuristics for the time dependent team orienteering problem: Application to tourist route planning. Computers and Operation Research, 62, 36-50. doi:10.1016/j.cor.2015.03.016 Gendreau, M., Laporte, G., & Semet, F. (1998). A tabu search heuristic for the undirected selective travelling salesman problem. European Journal of Operational Research, 106(2–3), 539–545. doi:10.1016/S0377-2217(97)00289-0 Golden, B., Levy, L., & Vohra, R. (1987). The orienteering problem. Naval Research Logistics, 34, 307-318. doi:10.1002/1520-6750(198706)34:3<307::AID-NAV3220340302>3.0. CO;2-D Gunawan, A., Yuan, Z., & Lau, H. C. (2014). A Mathematical Model and Metaheuristics for Time Dependent Orienteering Problem. In PATAT 2014: Proceedings of the 10th International Conference of the Practice and Theory of Automated Timetabling, 26–29 August 2014 (pp. 202–217). Research Collection School Of Information Systems. Mahfoud, S. W. (1992). Crowding and preselection revisited. In Proceedings of the 2nd International Conference on Parallel Problem Solving from Nature (PPSN II), Brussels, Belgium, 1992 (pp. 27–36). Amsterdam: Elsevier. Ostrowski, K. (2015). Parameters Tuning of Evolutionary Algorithm for the Orienteering Problem. Advances in Computer Science Research, 12, 53–78. Ostrowski, K., Karbowska-Chilinska, J., Koszelew, J., & Zabielski, P. (2017). Evolution-inspired local improvement algorithm solving orienteering problem. Annals of Operations Research, 253(1), 519-543. doi:10.1007/s10479-016-2278-1 Ostrowski, K. (2017). Evolutionary Algorithm for the Time-Dependent Orienteering Problem. In K. Saeed, W. Homenda, & R. Chaki (Eds.), Computer Information Systems and Industrial Management. CISIM 2017, Lecture Notes in Computer Science (10244, pp. 50–62). Cham: Springer. doi:10.1007/978-3-319-59105-6_5 p g Schilde, M., Doerner, K., Hartl, R., & Kiechle, G. (2009). Metaheuristics for the biobjective orienteering problem. Swarm Intelligence, 3(3), 179–201. doi:10.1007/s11721-009-0029-5 Tasgetiren, M. (2001). A genetic algorithm with an adaptive penalty function for the orienteering problem. Journal of Economic and Social Research, 4(2), 1–26. Vansteenwegen, P., Souffriau, W., Vanden Berghe, G., & Oudheusden, D.V. (2009). 7. CONCLUSION In this paper a metaheuristic solving the Time-Dependent Orienteering Problem with Time Windows (TDOPTW) was presented and applied to tourist trip planning in public transport networks. The algorithm was tested on public transport and POI networks of Białystok and Athens and in all cases obtained optimal or close to optimal solutions (tours) in short execution times. The composition of evolutionary algorithm and local search heuristics confirmed to be effective for the problems from the Orienteering Problem family (high-quality results were previously obtained by the author for the OP and TDOP benchmarks). Further re- search will concentrate on adaptation of the proposed method to the Time-Dependent Team Orienteering Problem with Time Windows (TDTOPTW). In this version of the problem m paths are generated (instead of one) and effective TDTOPTW solutions can be applied to planning multi-day tours. 18 REFERENCES A guided local search metaheuristic for the team orienteering problem. European Journal of the Operational Research, 196(1), 118–127. doi:10.1016/j.ejor.2008.02.037 Verbeeck, C., Sörensen, K., Aghezzaf, E.H., & Vansteenwegen, P. (2013). A fast solution method for the time-dependent orienteering problem. European Journal of Operational Research, 236(2), 419–432. doi:10.1016/j.ejor.2013.11.038 19
https://openalex.org/W1969650498
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English
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Do the Historical Biogeography and Evolutionary History of the Digenean Margotrema spp. across Central Mexico Mirror Those of Their Freshwater Fish Hosts (Goodeinae)?
PloS one
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100 0 100 Kilometers H I L F B A K J C D G E N 2 -115 -105 -110 -110 -95 -90 -30 -20 -15 -115 -105 -100 -95 -90 -30 -25 -20 -15 -25 -110 M Figure S1. Hydrological systems from this study. Black dots indicate collecting sites within each of the water bodies, represented by uppercase letters in coloured circles (A = Lower Conchos River; B = Upper and Middle Mezquital River; C = Lower Lerma River; D = Zacapu Lake; E = Cuitzeo Lake F = Pátzcuaro Lake; G = Zirahuén Lake; H = Armería-Ayuquila Rivers; I = Cuzalapa River; J = Cotija; K = Lower Balsas River; L = Upper Balsas River. Codes correspond 100 0 100 Kilometers H I L F B A K J C D G E N 2 -115 -105 -110 -110 -95 -90 -30 -20 -15 -115 -105 -100 -95 -90 -30 -25 -20 -15 -25 -110 M Figure S1. Hydrological systems from this study. Black dots indicate collecting sites within each of the water bodies, represented by uppercase letters in coloured circles (A = Lower Conchos River; B = Upper and Middle Mezquital River; C = Lower Lerma River; D = Zacapu Lake; E = Cuitzeo Lake F = Pátzcuaro Lake; G = Zirahuén Lake; H = Armería-Ayuquila Rivers; I = Cuzalapa River; J = Cotija; K = Lower Balsas River; L = Upper Balsas River. Codes correspond Figure S1. Hydrological systems from this study. Figure S1. Hydrological systems from this study. Black dots indicate collecting sites within each of the water bodies, represented by uppercase letters in coloured circles (A = Lower Conchos River; B = Upper and Middle Mezquital River; C = Lower Lerma River; D = Zacapu Lake; E = Cuitzeo Lake; F = Pátzcuaro Lake; G = Zirahuén Lake; H = Armería-Ayuquila Rivers; I = Cuzalapa River; J = Cotija; K = Lower Balsas River; L = Upper Balsas River. Codes correspond to those found in Table 1 of the manuscript.
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https://downloads.hindawi.com/journals/jat/2022/1785199.pdf
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Pricing Method of the Flexible Bus Service Based on Cumulative Prospect Theory
Journal of advanced transportation
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Hindawi Journal of Advanced Transportation Volume 2022, Article ID 1785199, 14 pages https://doi.org/10.1155/2022/1785199 Research Article Pricing Method of the Flexible Bus Service Based on Cumulative Prospect Theory Wanjing Ma ,1 Yuhang Guo ,1 Kun An ,1 and Lei Wang 1 2 1,2 The Key Laboratory of Road and Traffic Engineering, Ministry of Education, Tongji University, Shanghai 201804, China College of Transport and Communications, Shanghai Maritime University, Shanghai, China Correspondence should be addressed to Kun An; kunan@tongji.edu.cn Received 26 October 2021; Revised 11 January 2022; Accepted 5 February 2022; Published 16 March 2022 Academic Editor: Ren-Yong Guo Copyright © 2022 Wanjing Ma et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Pricing directly affects the sustainable development of the flexible bus service. This study proposes a profit maximization model and a social welfare maximization model for the flexible bus operator based on the cumulative prospect theory. Fares and uncertain travel time due to unforeseen detours in serving passengers jointly affect passengers’ mode choice. On the other hand, fares and passengers’ probabilistic choices over the flexible bus jointly determine the profits of the flexible bus company and social welfare. This study explores the relationship between the probability of passengers choosing the flexible bus, trip fares, and uncertain travel time. Serving more passengers indicates more profits, which also results in longer detour time thus decreasing the probability of passengers choosing the flexible bus. Considering the interactive influence among passengers, we further calculate the detour time distribution. Finally, a pricing model is established to compensate for the side effects of the detour. The results show that heterogeneous fares can help the flexible bus company to obtain higher profits but have negligible influence on social welfare. In addition, the development of long-distance services and regulations over the detour time can also help to obtain more profits. 1. Introduction The flexible bus can be regarded as a bridging mode between the conventional fixed-route transit and dial-a-ride services. The flexible bus typically uses small or medium-sized vehicles to provide door-to-door travel services subject to passenger demand [1]. Since taxies are way more expensive despite their high level of service, the flexible bus service with its high flexibility and customization capability is an attractive alternative for high-to-medium income customers [2]. It is critical for operators to seek an appropriate pricing method for the flexible bus service. On the one hand, reasonable pricing can affect the behavior of travelers, reduce the demand for private cars/taxies, and transfer it to public transit, thereby alleviating urban traffic congestion. On the other hand, pricing also directly affects the financial sustainability of the flexible bus company. In recent years, a growing number of studies investigated the pricing problem for many emerging travel modes such as flexible bus and customized bus. Li et al. [3] formulated a competitive game model in which the objective was to maximize the profits of customized bus services and ridesharing based on passengers’ transport mode choices. Sayarshad and Gao [4] developed a dynamic pricing scheme that utilized a balking rule considering socially efficient levels and revenue-maximizing price. An equilibriumjoining threshold was obtained by imposing a toll on the customers who joined the on-demand mobility system. Kaddoura et al. [5] proposed an agent-based transport simulation to investigate different design concepts for the demand-responsive transit. The simulation results show that a small service area and low prices may result in an unwanted mode shift effect from walk and bicycle to Demand Responsive Transit. Gong et al. [6] constructed a game theory model between the customized city bus service and the conventional urban bus transportation to maximize the profits of the two transportation modes. Wang et al. [2] integrated the disaggregated trip choice model with the 2 vehicle routing model to determine incentive schemes. They concluded that passengers’ sensitivity towards incentives is decisive to the result. In addition, there are many studies on the pricing for other on-demand responsive travel modes, such as ridehailing and ride-pooling. Ozkan [7] studied the interrelationship between pricing and matching decisions of a ridesharing firm. He formulated a stylized ride-sharing model that captured customer and driver behaviors considering the geospatial nature of the system. The results showed that optimizing the pricing decisions alone with fixed matching rules did not increase the number of matchings in general. Yan et al. [8] designed and implemented a matching and pricing algorithm at scale to strike a balance between model complexity and accurate description of the marketplace dynamics. Wang et al. [9] found that if the platform offers the carpool service option, they can achieve a larger market coverage and the riders can enjoy more affordable rides without compromising on service quality. Bai et al. [10] considered an on-demand service platform using earningsensitive independent providers with heterogeneous reservation prices (for work participation) to serve its time and price-sensitive customers with the heterogeneous valuation of the service. Zhong et al. [11] examined how an on-demand ride-hailing platform in competition with the traditional taxi industry designs its pricing strategies under unregulated and regulated pricing scenarios. They found that the monopolistic on-demand ride-hailing platform’s price rate and profit under the unregulated pricing scenario are relatively higher than those under the regulated pricing scenario. Detours are a problem faced by both the flexible bus and carpooling companies. However, few studies considered how the detour time would affect the pricing strategy of the flexible bus. Ke et al. [12] innovatively established a set of nonlinear equations to explore the relationships between the platform decision variables (i.e., trip fare) and endogenous variables (e.g., actual detour time) in ride-sourcing markets with and without on-demand ride-pooling services. By considering the extra detour time experienced by passengers and drivers, they found that decrease in trip fare not only directly increases passenger demand due to negative price elasticity, but also reduces actual detour time, which in turn increases passenger demand. Zhang and Nie [13] established a market equilibrium based on a spatial driver–passenger matching model that determines the passenger wait time for both solo and pooling rides. They found the system’s benefit diminishes quickly as the average en-route detour time increases. Both ride pooling and flexible bus are travel demandresponsive travel modes and how to pricing for both of them considering the uncertainty of the detour time is a challenging problem. However, a flexible bus can serve more passengers at the same time, making possible detours outcomes more complicated. The uncertainty in detour time affects passengers’ travel decisions to a greater extent, thereby affecting demand. Only few pricing studies considered travel decisions under uncertain travel time conditions. Choi et al. [14] applied the mean-risk theory to analytically explore how the risk attitude of customers affects the optimal service pricing decision of the on- Journal of Advanced Transportation demand platform. Wu et al. [15] proposed a choice-based framework for modeling the supply/demand interaction in risky choice contexts. The model allowed the system operator to set an optimal pricing strategy regardless of whether user risk preferences are risk-seeking or riskaverse. There are few studies on the relationship between pricing, detours, and passenger decision-making under uncertain conditions. Instead, most existing studies considered the relationship between price and demand from a macro perspective. Flat and homogenous fare is provided to all passengers [3, 6]. When passengers receive different service levels in terms of detour level, their fares should be different. Cumulative prospect theory (CPT) is widely used to solve travel decision-making problems and transportation pricing problems. As a descriptive decision-making model under uncertainty, the prospect theory was proposed by Kahneman and Tversky [16] as a critique of the expected utility theory. In 1992, Kahneman and Tversky [17] extended their model to CPT. CPT is based on the assumption of bounded rationality of decision-makers and can describe decision-makers’ behavior under uncertain conditions more accurately. Katsikopoulos et al. [18] found that drivers were risk-averse when choosing among routes in the gain domain and risk-seeking in the loss domain. It is consistent with the view of CPT. Sepehr et al. [19] introduced a CPT-based framework for mode choice modeling using observational data. The framework utilized CPT for modeling reliability in the trip-based models. CPT has also been widely applied to congestion pricing. Liu et al. [20] considered the psychological factors of passengers in the congestion pricing model and verified the feasibility of the model based on user equilibrium and CPT. Xu et al. [21] developed an optimal congestion pricing model in which user equilibrium was adopted to capture travelers’ response to pricing signals under risk based on CPT. However, the application of CPT in the pricing of the flexible bus is limited. We aim to study the pricing of the flexible bus service considering the interaction between passenger travel behavior and fares and thus propose a profit-maximization pricing strategy for the flexible bus system based on CPT. Considering the travel time of the flexible bus is uncertain due to its high route flexibility, we can apply CPT to our pricing model. The relationship of detour time distribution, fares, and acceptance of detours (choosing to take the flexible bus) are explored. On this basis, considering the detour problem of the flexible bus, we build a pricing model under static demand for the flexible bus company with the goal of expected profit maximization and social welfare maximization. In summary, the aims of this research are as follows: (1) Under uncertain travel time of trips by the flexible bus, we explore the influence of fares and uncertain travel time on passengers’ travel mode choices based on CPT (2) We establish two customized pricing models with the objective of profit maximization for the flexible Journal of Advanced Transportation bus company and social welfare, considering the impacts of trip detours on-demand loss The remainder of this paper is organized as follows. Section 2 establishes the mode choice model and the pricing model. The parameters are calibrated through a stated preference (SP) survey. Section 3 describes the design of two case studies and analyzes the results. The last section summarizes the innovations and conclusions. 2. Methodology In this section, we first introduce the hypotheses used in the flexible bus pricing problem. Based on prospect theory, we calculate the perceived travel time utility of passengers. Taking the travel time utility and out-of-pocket costs as the components in the utility function, we can obtain the probability of passengers taking flexible buses for a given detour time. In addition, considering the mutual influence among passengers in each other’s travel time, we develop a series of equations to obtain the detour time distribution. Finally, a flexible bus pricing model is constructed, which aims at maximizing the bus company’s profit and maximizing the social welfare respectively. The model parameters are calibrated through the SP survey and Maximum Likelihood Estimation (MLE). The main ideas are shown in Figure 1. 2.1. Problem Description. We consider regional flexible bus service in this study [22], which allows vehicles to operate in a demand-responsive way through reservation within the service area. Passengers can only board or alight in the predefined service areas. The pick-up region and drop-off region are connected by a non-stop fast route. It can be regarded as a variant of customized buses. Figure 2 illustrates the operation of the regional flexible bus. In this paper, we aim to investigate the pricing problem for this regional flexible bus service. The flexible bus adopts small and medium-sized vehicles and provides door-to-door services based on reservation. In the responsive area, the stops and bus routes depend on the demand of passengers, and the demand of passengers is elastic which is subject to the utility of the flexible bus. Compared with the taxi, the flexible bus will detour when delivering multiple passengers. More passengers to be served will probably lead to longer detour time. To passengers, a longer travel time would decrease the utility of the flexible bus thus affecting his/her mode choice probability. It is necessary to make reasonable pricing to compensate for the side effects of detours so as to make flexible buses competitive with taxies. In addition, as flexible buses may adjust routes dynamically while en-route, the travel time of passengers on-board may be prolonged and thus is uncertain. Passengers’ risk attitude and personal preference also influence passengers’ decision-making in the case of uncertain travel time. Therefore, it is necessary to accurately measure the impact of these factors on passenger decision-making to obtain the probability of passengers choosing the flexible bus. The mode choice probability and ticket price jointly 3 affect the expected profit of the flexible bus company and the social welfare. This section solves the pricing problem considering the interactions among passengers in the system. The price for each passenger is optimized to maximize the expected profit and the social welfare respectively. Due to the similarity of flexible bus and taxi services, we assume passengers can choose between the flexible bus and the taxi for their trip. They mainly consider the travel time and the fare assuming the other influencing factors are the same. The flexible bus knows the demand of passengers in advance through the reservation, but it is uncertain whether passengers will take it in the end. After knowing the passengers’ demand, the flexible bus will plan the route. If the passenger eventually chooses to get on the bus, the bus will pick him up. According to the probability of passenger boarding, the flexible bus can estimate the travel time through the probability of passengers getting on the bus. Before boarding, the flexible bus displays passengers the fare, travel time, possible detour time, and corresponding probabilities (in this paper, they are captured by the detour time distribution). Detour time refers to the increased time for passengers due to picking up other passengers (the time loss for waiting for boarding, etc.) after boarding compared with the shortest travel time from the origin to the destination. The shortest travel time is equal to the travel time of a taxi. The distribution of detour time refers to the detour time and its corresponding probability. 2.2. Behavior of Passengers. When passengers make mode choice decisions, they will be affected by many factors such as travel time, cost, and uncertainty of travel time [5]. In addition, passengers will also be influenced by their risk attitudes and preferences [21]. Considering the characteristics of the flexible bus, serving other passengers leads to the increase of uncertain detour time for the loaded passengers. The uncertain travel time and fare jointly affect the passengers’ mode choice decisions. This part explores the interrelationship between the distribution of detour time, the fare, and the acceptance of detours under the condition of uncertain travel time of the flexible bus. 2.2.1. Perceived Time Utility. Most of the traditional travel decision-making models are based on the expected utility theory, assuming that the decision-maker is entirely rational. In fact, people in the process of making travel decisions are often affected by the traveler’s habits, attitude towards risk, preferences, and other factors. Decision-makers often canno’t be entirely rational. CPT was developed by Kahneman and Tversky [17] based on prospect theory (PT), which is different from the traditional expected utility theory (EUT). CPT has three main observations about an individual’s bounded rationality. (i) People usually consider possible outcomes relative to a certain reference point (x0 ) rather than to the final state. The payoffs are defined as the gains or losses relative to x0 before making choices. The payoffs that people perceive can be described by a concave function for gains and a convex function for losses which results in diminishing sensitivity. 4 Journal of Advanced Transportation Mutual Influence among Passengers Behavior of Passengers Perceived Time Utility: Calculate the Time Utility Perceived by the passengers based on the CPT Detour Time Distribution: Calculate the detour time distribution using the probability of passengers choosing to take the flexible bus Calibration of Parameters: Calibrate the parameters of the pricing model through SP survey and MLE Acceptance of Detours: Calculate the probability of passengers choosing to take the flexible bus based on the utility maximization theory Pricing Model: Calculate the fare for each person with the goals of maximizing profit and maximizing social welfare Figure 1: Main idea of the method. can lead to k different outcomes, quantified by x1 , x2 , . . . , xk , The outcome i happens with probability Pi . Each alternative can be seen as a prospect (xi , Pi ). The following value function proposed by Kahneman and Tversky [17] is used in this paper: Region 1 Region 2 Responsive area Fixed route (between regions) Responsive route (within regions) Responsive boarding station Responsive alighting station Figure 2: Operation of the regional flexible bus. (ii) People tend to be loss aversion. People are more sensitive to losses than gains. (iii) People tend to overweight the probability of extreme, but rare events, and underweight more common events. People’s decisions are affected by the decision weights, not actual probabilities. In conclusion, CPT argues that decision-makers perceive values v(xi ) (travel time in the case of this paper) differently from the actual values xi , and probabilities Pi (probability of experiencing a certain travel time for a given trip) are converted to decision weights w(Pi ). Although some studies have considered the influence of detour time, they have not considered the uncertainty of detour [12]. Due to demand uncertainty, the travel time of the flexible bus is uncertain. Therefore, the choice between flexible public transportation and other modes of transportation is a typical travel decision-making problem under uncertain conditions. Given that CPT provides a well-supported descriptive paradigm for individuals’ decisionmaking under risk or uncertainty, we can apply CPT to measure travelers’ perceived utility of time. We assume that a passenger intends to choose between a flexible bus and a taxi for a trip. Choosing each alternative α ⎪ ⎧ ⎨ xi − x 0 􏼁 , x i ≥ x 0 , v xi 􏼁 � ⎪ where 0 < α, β < 1, λ ≥ 1, ⎩ −λ x − x 􏼁β , x < x , 0 i i 0 (1) where x0 is the reference point; α is the exponent of the value function over the gain region, and β is the exponent of the value function over the loss region. v(xi ) is the value function, reflecting an individual’s perceived value. The parameters α and β measure the degree of diminishing sensitivity of the value function. λ is the loss aversion coefficient, indicating that individuals are more sensitive to losses than gains. The following probability weighting function by Kahneman and Tversky [17] is used: c w Pi 􏼁 � Pi c c 1/c 􏼂 Pi + 1 − P i 􏼁 􏼃 where 0 < c < 1, (2) where c is the probability weighting parameter, representing the level of distortion in probability judgment in the decision-making process. w(Pi ) is the probability weighting function, reflecting an individual’s perception of probability. Figures 3 and 4 show the value function and the weighting function. As shown in Figures 3 and 4, the value function v(xi ) is S-shaped, concave in the gain region and convex in the loss region. Besides, individuals are more sensitive to losses than gains. Furthermore, the probability weighting function w(Pi ) expands the influence of rare events and shrinks the influence of common events. The cumulative prospect value is defined as Journal of Advanced Transportation 5 v (x) k CPV tm 􏼁 � 􏽘 v􏼐tm,i 􏼑π􏼐Pm,i 􏼑, (10) i�1 x0 where CPV(tm ) is the perceived time utility of mode m. (6) calculates the perceived utility v(tm,i ) corresponding to the travel time tm,i . (7), (8), (9) calculate the decision weight π(Pm,i ) corresponding to the travel time tm,i . (10) calculates the total perceived time utility of mode m. x Figure 3: Value function. CPV � 􏽘 v xi 􏼁π Pi 􏼁, (3) k π Pi 􏼁 � w Pi + Pi+1 · · · + Pk 􏼁 − w Pi+1 + Pi+2 · · · + Pk 􏼁, where i � 1, 2, . . . , k − 1, (4) π Pk 􏼁 � w Pk 􏼁, β v􏼐tm,i 􏼑 � −λ􏼐tm,i − t0 􏼑 , tm,i ≥ t0 , (6) c Pm,i c Vm � 􏽘 θm ym , (5) The decision weight π(Pi ) is calculated based on the cumulative distribution function. All potential outcomes are ranked in increasing order in terms of preference. In these equations, k is the number of all potential outcomes, and i denotes a generic outcome. For mode-alternative m, the travel time can be tm,1 , tm,2 , · · · , tm,k with probabilities Pm,1 , Pm,2 , · · · , Pm,k , respectively. To apply CPT, we need to define the reference point, the value function, and the weighting function first. In the case of the flexible bus detour problem, people will pay more attention to the increase in detour time compared with the shortest travel time when making travel decisions. Therefore, the shortest travel time t0 (equal to taxi travel time) is selected as the reference point. (1) is assumed to be the value function. (2) is assumed to be the probability weighting function. Since tm,i ≥ t0 , ∀i ∈ k, we only model in the loss domain. The calculation process of perceived time utility CPV(tm ) is as follows: w􏼐Pm,i 􏼑 � 2.2.2. Acceptance of Detours. We assume that the speeds of the flexible bus and the taxi are equal. The difference in travel time between the flexible bus and the taxi is because that the flexible bus needs to detour to serve multiple passengers in one trip. Therefore, we define the probability of passengers choosing a flexible bus as the acceptance of detours. According to the assumption, the fare will also have an important impact on passengers’ decision-making. When travelers make travel decisions, they always choose the one with a larger utility, which is called the utility maximization theory. The formula of the utility maximization theory is as follows: c 1/c , 􏽨Pm,i + 􏼐1 − Pm,i 􏼑 􏽩 (7) A where ym is the characteristic variable and θm is the parameter reflecting travelers’ perceived relative importance of different attributes. According to the discussion above, travel time and travel cost are selected as characteristic variables. Considering that travel time is uncertain, the utility of travel time is more suitable to be described by CPT. The travel cost is a deterministic factor. Therefore, the probability estimation and risk attitude of travelers will not affect the utility of the travel cost. The modified utility function is MVm � β0 σ m + βt CPV tm 􏼁 + βc Cm , p� (8) where i � 1, 2, . . . , k − 1 (12) where Cm is the travel cost of mode m; CPV(tm ) is the perceived travel time utility of mode m; σ m is a dummy variable indicating whether a particular mode-alternative is the flexible bus or not; β0 is the mode-specific constant added to capture the effect of unforeseen variables; βc is the coefficient of cost, and βt is the coefficient of time. CPT can be used to calculate the value of the modified utility (MVm ) of each mode (the flexible bus and the taxi) and the mode decision between the two modes. Acceptance of detours can be described by a Logit function: π􏼐Pm,i 􏼑 � w􏼐Pm,i + Pm,i+1 · · · + Pm,k 􏼑 − w􏼐Pm,i+1 + Pm,i+2 · · · + Pm,k 􏼑, (11) p� exp􏼐MVfb 􏼑 exp􏼐MVfb 􏼑 + exp MVtaxi 􏼁 , (13) 1 1 + exp􏼐−β0 + βt 􏼐CPV ttaxi 􏼁 − CPV􏼐tfb 􏼑􏼑 + βc ΔC􏼑 , (14) π􏼐Pm,k 􏼑 � w􏼐Pm,k 􏼑, (9) ΔC � Ctaxi − Cfb , (15) 6 Journal of Advanced Transportation 1.0 w (p) 0.8 0.6 0.4 0.2 0.0 0.0 0.2 0.4 p 0.6 0.8 1.0 Figure 4: Weighting function. where p is the acceptance of detours; fb refers to the flexible bus; MVfb is the modified utility of the flexible bus; MVtaxi is the modified utility of the taxi, and ΔC is the difference between taxi cost and flexible bus cost. CPV(ttaxi ) is equal to 0 and CPV(tfb ) can be calculated by (6), (7), (8), (9), and (10). Therefore, passengers’ acceptance of detour can be simplified as p� 1 1 + exp􏼐−β0 + Δti � ti − t0 , βt λ 􏽐ki�1 β Δti 􏼁 π Pi 􏼁 + βc ΔC􏼑 , (16) (17) where Δti is the detour time for taking the flexible bus. 2.3. Detour Time Distribution. In (16), the probability of taking the flexible bus is affected by the perceived time utility and fare. The perceived time utility is jointly affected by the detour time and its corresponding probability. Calculating the perceived time utility of a passenger requires the detour time distribution. By analyzing the reasons for the detour, we propose a method to calculate the time distribution of the detour. For a certain passenger, the detour he/she faced is caused by serving other passengers during his/her ride. Generally speaking, the more stations served, the longer the detour time the passenger suffers. However, the detour does no’t necessarily happen. It is related to the probability of passengers choosing to take the flexible bus. Considering that the passenger demand is usually densely distributed in a certain area, it can be assumed that, for each passenger, the detour time increases by T for serving every extra station (including the boarding station and the alighting station). To explain the method, we consider a case of five passengers, A-E, and they get on and off at given stations. Figure 5 shows everyone’s boarding and alighting stations. Since the flexible bus provides door-to-door service, the 2 B (on) C (on) D (on) 4 E (on) A (off) A (on) 1 6 B (off) D (off) 3 5 C (off) E (off) The boarding or alighting station of A The boarding or alighting station of B-E The route of a taxi The route of a flexible bus A (on) : A gets on at this station A (off) : A gets off at this station Figure 5: Boarding and alighting stations of A-E. boarding and alighting stations are also the origin and the destination respectively. Take A as an example, if B-E choose to take the flexible bus, A will be affected by the detour caused by serving B-E. If B-E do no’t take the flexible bus, A will not suffer a detour. This is related to the probability that B-E choose to take the flexible bus. The probabilities of B, C, D, and E taking the flexible bus are pB , pC , pD , and pE respectively. They further affect the probability of the flexible bus serving Stations 2–5. The probabilities of serving Stations 2–5 are sp2 , sp3 , sp4 , and sp5 respectively, which can be calculated as follows: sp2 � 1 − 1 − pB 􏼁 1 − pC 􏼁 1 − pD 􏼁, (18) sp3 � 1 − 1 − pB 􏼁 1 − pD 􏼁, (19) sp4 � pE , (20) Journal of Advanced Transportation sp5 � 1 − 1 − pC 􏼁 1 − pE 􏼁, 7 (21) According to the assumption, the detour time increases by T for serving every extra station. For A, the detour time can be 0, T, 2T, 3T, and 4T with probabilities P1 , P2 , P3 , P4 , and P5 , respectively. By combining Stations 2–5, the corresponding probability of the detour time can be obtained. Taking the detour time Δt � 0 as an example, the corresponding probability is calculated as follows: P1 � P(Δt � 0) � 1 − sp2 􏼁 1 − sp3 􏼁 1 − sp4 􏼁 1 − sp5 􏼁, The operating cost is assumed to be L, which is the system parameter related to operating distance, the vehicle types, fuel consumption, and other factors of the flexible bus system. The calculation of operating cost is similar to the calculation method of taxi fare. The operating distance is composed of the operating distance within the region and the operating distance between regions. The operating distance between regions is a constant, while operating distance within the region is related to the spatial distribution of passengers. Besides, detours within the region will also affect the operation costs. The operating cost L is (22) where sp2 , sp3 sp4 , and sp5 can be calculated by (18), (19), (20), and (21). P2 , P3 , P4 , and P5 can be calculated in the same way. The possible detour time for A is (0, T, 2T, 3T, 4T, 5T). Then, we can get the detour time distribution of A. Similarly, we can use this method to calculate the detour time distribution for customers B-E. This idea of calculating detour time distribution can then be extended to a flexible public transport system with Q individuals. In general, for a passenger, his/her detour time is related to the number of other stations served by the flexible bus. The probability corresponding to the detour time is determined by the probability of passengers choosing to take the flexible bus in other stations. 2.4. Pricing Model 2.4.1. Service Provider Profit. The profit of flexible buses is the fare revenue minus the operating cost. The expected fare revenue of passenger is (23) where xj is the fare of the flexible bus for passenger j and pj is the probability of passenger j taking the flexible bus. According to (12), (13), (14), (15), (16), and (17), pj is related to detour time and the difference between taxi fare c and flexible bus fare xj : 1 β 1 + exp􏼒−β0 + βt λ 􏽐ki�1 􏼐Δti,j 􏼑 π􏼐Pi,j 􏼑 + βc 􏼐c − xj 􏼑􏼓 , (26) where φ is the fare of taxi per kilometer; s is the travel distance between regions; v is the average speed of the flexible bus and Δt is the expected detour time. Δt can be calculated by the distribution of detour time mentioned in Section 2.4. The profit of the service provider Z1 can be expressed as Q Z1 � 􏽘 xj · pj − L, (27) j�1 where L is the operating cost; pj is the probability of passenger j taking the flexible bus, and c is the fare of the taxi. 2.4.2. Passenger Surpluses. The passenger surplus is the fare that a passenger is willing to pay for the flexible bus service minus the actual out of pocket costs. The fare that a passenger is willing to pay for the flexible bus service can be expressed as: W � c − UΔt , k rj � xj · pj , pj � L � φ(s + vΔt), (28) β UΔt � βt λ 􏽘 Δti 􏼁 π Pi 􏼁, (29) i�1 where W is the fare that a passenger is willing to pay, and UΔt is the disutility caused by detours. The passenger surpluses Z2 can be expressed as: Q Z2 � 􏽘􏼐Wj − xj 􏼑, (30) j�1 (24) Taxi fare c is related to the travel distance of the passenger. The travel distance is composed of the travel distance within the region and the travel distance between regions. The travel distance between regions is a constant, while travel distance within the region is related to the origin and the destination of the passenger. Considering that the travel distance between regions accounts for the main part, we assume that ticket fare and the distance between regions are positively correlated. The taxi fare c is: c � μs, (25) where μ is the fare of taxi per kilometer and s is the travel distance between regions. 2.4.3. Optimization Model of Fares. We consider two objectives (profit maximization and social welfare maximization) to optimize the fare of the flexible bus. (i) Expected profit maximization: compared with the taxi, the flexible bus will detour, so the fare of the flexible bus will not exceed the fare of the taxi. The profit maximization model of the flexible bus can be expressed as max Z1 (31) 0 ≤ xj ≤ c, (32) s.t. (12)-(27) 8 Journal of Advanced Transportation (ii) Social welfare maximization: social welfare includes the profit of the service provider and passenger surpluses, considering the interests of the flexible bus operator and the passengers simultaneously. The profit of the flexible bus operator should not be less than the threshold θ. The social welfare maximization model of the flexible bus can be expressed as max Z1 + Z2 , (33) s.t. (12)-(30) Z1 ≥ θ, (34) (12), (13), (14), (15), (16), and (17) calculate the probability of passenger j taking the flexible bus. (18), (19), (20), (21), and (22) propose a method of calculating the time distribution of each passenger. (23) calculates the expected fare revenue of passenger j. (24) displays the probability of passenger j taking the flexible bus. (25) calculates the taxi fare. (26) calculates the operating cost. (27) calculates the service provider profit. (28) calculates the fare that a passenger is willing to pay for the flexible bus service. (29) calculates the disutility caused by detours. (30) calculates the passenger surpluses. The objective function aims at maximizing the expected profits of the flexible bus and maximizing the social welfare respectively. Constraint (32) ensures that the fare is within a reasonable range. Constraint (34) ensures that the profit of the flexible bus operator should not be less than a certain threshold. Combined with the calculation of detour time distribution proposed in Section 2.3, we can find that the passengers in the flexible bus system affect each other. Take the service order as A-B-A-B as an example, the reduction in A’s fare will increase A’s probability of choosing the flexible bus. Because of the increase in the probability of A choosing the flexible bus, the probability of B’s detour also increases, resulting in a decrease in the probability of B choosing to take the flexible bus. Therefore, the fare of each passenger directly affects his probability of taking the flexible bus, and indirectly affects the probability of other people’s detours, thereby affecting the probability of other passengers’ taking the flexible bus. Figure 6 shows the relationship between A and B. Therefore, a reasonable price should be set for each passenger in the flexible bus system to maximize the expected profit or the social welfare. The final output of the pricing model is the optimal fare that is shown to each reserved passenger before the flexible bus departs. However, the model is under static demand. The actual operation of a flexible bus is a dynamic process. When a passenger refuses service or completes the service, new passengers will enter the system. This situation will lead to an increase in detour time. It will reduce the level of service for loaded passengers who have already received the initial fare on the bus. Correspondingly, the fare should be reduced. From the perspective of fairness to passengers, the result calculated by the profit maximization model should be the highest price given by the flexible bus in real-world operation. 2.5. Calibration of Parameters. To calibrate the parameters of our model, we conducted an online stated preference survey. The SP survey includes three parts: The first part is the individual socioeconomic attributes of the participants. The second part is regarding people’s risk attitudes towards time. We design a set of binary travel plan choices. Each has a different travel time distribution. The average travel time of the choice is equal, but the variance is not. Participants need to choose their preferred travel plan. The third part is related to mode choice between the flexible bus and the taxi. Finally, 246 questionnaires were returned in this SP survey. After sorting the questionnaires, 205 valid questionnaires were obtained, with an effective rate of 83%. Overall, the collected data samples are representative. The model parameters were calibrated using the data of the SP survey. In many existing studies on travel decision-making based on CPT, researchers use the parameters in the value and weighting functions which are directly estimated by Kahneman and Tversky. However, parameters in Kahneman and Tversky are estimated from the results of gambling in the economic field. In different scenarios, the parameters β of the value function in the loss domain of different travelers should be different [21]. The values of β in our model are estimated based on the experimental results of stated choice questions of the second part and the CPV parameter values (i.e., λ � 2.25 and c � 0.69). A logit model and MLE are used to estimate the value function parameter β. On this basis, the values of β0 , βt , βc in our model are estimated by using logistic regression. Our estimation results are β � 0.60, β0 � −0.326, βt � 0.252, and βc � −0.285. The rate of substitution between CPV(t) and travel cost in our study is 0.252/0.285 � 0.88 RMB/min. For passengers, the detour is essentially a loss. Compared with taxi fares, the decrease of flexible bus fares is compensation for detours. Therefore, the results mean that travelers’ willingness to accept every unit increase in CPV(t) is about 0.88 RMB per minute in our SP survey. Passengers’ willingness to accept CPT(t) includes the willingness to accept detour time and the willingness to accept the uncertainty of travel time. Most studies on the value of time or uncertainty addressed users of cars, buses, and taxis, while few considered ride-sharing or flexible bus passengers [23]. There are mainly three approaches considering reliability in the utility maximization theory. Small [24] proposed a scheduling model to analyze travelers’ departure time choices to ensure on-time arrival. Small and Noland [25] improved Small’s scheduling model to understand choices under uncertainty by adding the probability distribution of travel time. The mean lateness at departure and/or arrival [26] is another approach to measuring the value of uncertainty. The mean-variance (MV) model [25] estimates the values of travel time and uncertainty within the utility maximization framework. We choose the mean-variance model to compare with our model based on CPT framework. In the mean-variance model, the utility of mode i is Ui � βt E ti 􏼁 + βSD SD ti 􏼁 + βc ci + βσ σ i , (35) where E(ti ) is the expected travel time of mode i, SD(ti ) is the standard deviation of travel time, ci is the ticket fare, σ i is Journal of Advanced Transportation 9 (+) Probability of B taking the flexible bus Fare of A (+) (+) (−) (−) Expected profit (−) (+) (+) Probability of A taking the flexible bus (−) Fare of B (+) direct effect indirect effect Figure 6: The relationship between A and B. a dummy variable indicating whether a particular modealternative is the flexible bus or not, and βt , βSD , βc and βσ are the parameters. The value of travel time and value of uncertainty can be defined as βt /βc and βSD /βc . We used the data based on the experimental results of stated choice questions to calibrate the parameters in the mean-variance model. The estimation results are βσ � −0.054, βt � 0.152, βSD � 0.018, βc � −0.311. The value of travel time is 0.49 RMB/min and the value of time uncertainty is 0.06 RMB/ min. The value of time uncertainty is too small, which is unreasonable. The rate of substitution between CPV(t) and travel cost in our model is 0.88 RMB/min, which is bigger than 0.49 RMB/min. Because our model considers the time uncertainty when calculating the value of travel time are shown in Table 1. In addition, travel time variability generates utility or disutility depending on the relationship between the reference point. Therefore, the time value and uncertainty perceived by travelers cannot be estimated separately. And according to the above analysis, the subjective perception value of the traveler will affect the utility. Therefore, it is more reasonable to apply CPT to describe the passengers’ decision-making behavior in this context. Table 1: Parameter calibration results of the mean-variance model. 3. Case Study km, v � 30 km/h, Q � 8, T � 2 min, μ � 3 RMB/km, φ � 4 RMB/km, and θ � 100 RMB. λ, c, β are parameters in CPT. λ, c are obtained by referring to the research of Tversky and Kahneman. β is calibrated through the SP survey. We set λ � 2.25, c � 0.69, and β � 0.60. β0 , βt , βc are the parameters in the pricing model, which are also calibrated through the SP survey. We set β0 � − 0.326, βt � 0.252, and βc � −0.285. In two cases, we omit the average detour time because the average detour time is much smaller than the travel time between regions. 3.1. Case Description and Parameter Settings. We suppose that there are two small areas, area R is a residential area, and area S is a commercial area. The distance between the two areas is 20 km. There are Q passengers going from R to S, and passengers can choose between flexible bus and taxi. The flexible bus can obtain the demand of all passengers in advance and determines the passengers’ boarding and alighting order at the stops. Two cases are set up in this section. Table 2 describes the stops where passengers get on and off the bus. Case 1 adopts the first-on, first-off service principle. In Case 2, there is no specific service principle (random service principle). The parameters of the two cases are set as follows: s, v, Q, T, μ, φ, and θ are system parameters. We set s � 20 Parameters Coef. P-value βσ βt βSD βc −0.054 0.712 0.152 0.000 0.018 0.615 −0.311 0.000 Table 2: Passengers’ boarding and alighting stops in Case 1 and Case 2. Stop Passenger Case 1 1 1 (on) 2 2 (on), 3 (on) 3 4 (on) 4 5 (on) 5 6 (on), 7 (on) 6 8 (on) Case 2 1 1 (on), 2 (on) 2 3 (on) 3 4 (on), 5 (on), 6 (on) 4 7 (on), 8 (on) Stop Passenger 7 8 9 10 11 12 1 (off) 2 (off), 3 (off) 4 (off) 5 (off) 6 (off), 7 (off) 8 (off) 5 6 7 8 3 (off), 6 (off), 7 (off) 2 (off), 4 (off) 5 (off) 1 (off), 8 (off) Note. 1 (on) means Passenger 1 gets on the flexible bus. 3.2. Results 3.2.1. Case 1. Table 3 shows the fares for each passenger in profit maximization and social welfare maximization 10 Journal of Advanced Transportation Table 3: Results of case 1. Passenger Detour stops Profit maximization model Social welfare maximization model Fares (RMB) Maximum profit (RMB) Fares (RMB) Maximum social welfare (RMB) models. In addition, the number of stops that affect each passenger’s detour is also listed. In the profit maximization model, the average fare is 43.4, and the std is 0.3. The expected maximum profit is 235.9. The fare of each passenger is almost the same. It is because that the number of detour stops (referring to the detour suffered by the passenger due to serving other stops) is the same. The increase in the fare of passenger 1 will result in a reduction in the probability of Passengers 2–8 taking the flexible bus. It is the same for every passenger. When the individual’s fare is set as the average, the expected profit is reduced to 235.8 with negligible differences from the maximum profit. In the social welfare maximization model, the average fare is 22.5, and the std is 1.2. The maximum social welfare is 381.9 with the constraint that the service provider profit is at least 100. The fare of each passenger is slightly different. When the individual’s fare is set as the average, the social welfare is also with negligible differences from the maximum social welfare. Figure 7 shows that the profit and social welfare (without the constraint that the service provider profit is at least 100 RMB) change with the fare. Here, we set the fare equal for each passenger. As the fare increases, the profit first increases and then decreases, reaching the maximum at around 43 RMB/trip, while the social welfare first remains almost unchanged and then gradually decreased after around 34 RMB/trip. 3.2.2. Case 2. Table 4 shows the fares for each passenger in profit maximization and social welfare maximization models. In addition, the number of stops that affect each passenger’s detour is also listed. In the profit maximization model, the average fare is 45.5, and the std is 2.2. The expected maximum profit is 254.8. In the profit maximization model, the average fare is 22.5, and the std � 2.64. The expected maximum profit is 254.8. Since the number of detour stops for each person is different, the individual fare is also different. Figure 8 shows the relationship between detour stops and fares in Case 2. When the travel distance is certain, the more stops you take, the lower the fare is. It is because the effective distance (the distance from the origin to the destination) is fixed for passengers. Detours caused by serving other stops increase the travel time of the passengers. Therefore, for the flexible bus system, the more detour stops a passenger travels, the lower the fare should be. This is consistent with the calculation results of our model. When an equal fare is used, the expected profit is 249.9, reduced by 1.9% compared to the 1 5 43.6 2 5 43.1 3 5 43.1 23.7 21.0 21.3 4 5 5 5 43.6 43.6 235.9 24.0 23.3 381.9 6 5 43.1 7 5 43.1 8 5 43.6 21.3 21.9 23.4 maximum expected profit, and the social welfare is 388.7. It shows that it is better to take a different fare for each user when aimed at gaining more profits. However, taking a different fare has negligible influence on social welfare. The travel distance, number of passengers, and other parameters of Case 1 and Case 2 are all the same except for the service order. By comparing Case 1 and Case 2, the maximum profit of Case 2 is 8.0% higher than Case 1, and the maximum social welfare of Case 2 is 1.8% higher than Case 1. This is due to the fact there are more detour stops in Case 1 that affect each passenger than in Case 2. It shows that the detour time has an important influence on the expected profit of the system. 3.3. Effects of the Travel Distance. We set the travel distance to vary from 10 to 40 km while maintaining the other parameters unchanged. Figure 9 shows that as the travel distance increases, the profit and the social welfare per unit distance increase, and the magnitude of the increase decreases. Take the maximum profit model as an example, when the travel distance is 10 km, the maximum profit per unit distance is 7.1 RMB; when the travel distance is 40 km, the profit per unit distance is 15.2 RMB. Compared with the travel distance of 10 km, the profit per unit distance increased by 114.1%, indicating that the flexible bus can obtain more profit in long-distance transportation. The trend of social welfare and profit is consistent. Therefore, the development of long-distance flexible bus services should be a priority strategy for the company and the whole society. Focusing on providing long-distance flexible public transportation services, such as between residential areas, transportation hubs, large shopping malls, and work areas can increase profit and social welfare. With the change of travel distance, the optimal fares per unit distance of the two objectives range from 1.8 to 2.5 and 1.1 to 1.2 respectively. The variation range is small, which indicates that the pricing model has good robustness when travel distance changes. 3.4. Effects of the Average Detour Time. The average detour time is caused by serving other stops for passenger boarding and alighting. We set the average detour time to vary from 1 to 9 minutes for serving one extra stop. Figure 10 shows that as the average detour time increases, the maximum expected profit and social welfare decrease, and the magnitude decreases. Take the maximum profit model as an example, when the average detour time is 1 minute, the maximum profit is 254.2 RMB; when the average detour time is Journal of Advanced Transportation 11 500 400 300 200 100 0 0 5 10 15 20 25 30 35 40 45 50 55 60 -100 -200 Fares (RMB) Social welfare (RMB) Profit (RMB) Figure 7: The relationship between fares, profit, and social welfare in Case 1. Table 4: Results of case 2. Passenger Detour stops Profit maximization model 2 4 43.7 3 2 45.8 16.6 21.2 24.5 1 2 51.0 27.0 49.0 25.0 Fares (RMB) Fares (RMB) Social welfare maximization model Fares (RMB) Maximum profit (RMB) Fares (RMB) Maximum social welfare (RMB) 1 6 42.0 47.0 45.0 43.0 41.0 4 5 2 3 45.7 44.7 254.8 22.4 24.3 388.7 6 1 47.1 7 0 50.0 8 3 44.9 23.2 25.9 22.1 23.0 21.0 19.0 17.0 0 1 2 3 4 Detour stops 5 6 (a) 7 15.0 0 3 4 Detour stops 5 6 7 (b) Figure 8: The relationship between detour stops and fares in Case 2. (a) The profit maximization model, (b) The social welfare maximization model. 9 minutes, the maximum profit is 161.1 RMB, substantially reduced by 36.6%. As the average detour time increases, a lower fare is needed to compensate for the delay suffered by passengers, resulting in a decrease in the maximum profit and social welfare. Therefore, the flexible bus company should pay attention to setting an upper limit for the detour time in operation. With the change of average detour time, the optimal fares per unit distance of the two objectives range from 1.7 to 2.3 and 1.1 to 1.2 respectively. This small range indicates that the pricing model has good robustness when average detour time changes. 3.5. Effects of the Value of Time. βt /βc measures the value of time, which is related to the individual’s attributes. We set βt /βc to vary from 0.6 to 1.5 RMB/min while maintaining the other parameters unchanged. Figure 11 shows that as the value of time increases, the maximum expected profit and social welfare decreases, and the magnitude decreases. Take the maximum profit model as an example, when βt /βc is 0.4 RMB/minute, the maximum profit is 265.5 RMB; when βt /βc is 1.2 RMB/minute, the maximum profit is 217.0 RMB, substantially reduced by 18.3%. As the value of time increases, the operator needs to compensate more for the same 12 Journal of Advanced Transportation 25.0 20.0 15.0 10.0 5.0 0.0 10 15 20 25 30 Travel distance (km) 35 40 Profit (RMB/km) Social welfare (RMB/km) Figure 9: Effects of the travel distance (Case 1). 450.0 400.0 350.0 300.0 250.0 200.0 150.0 100.0 50.0 0.0 1 2 3 4 5 6 Average detour time (min) 7 8 9 Profit (RMB) Social welfare (RMB) Figure 10: Effects of the average detour time (Case 1). 500.0 400.0 300.0 200.0 100.0 0.0 0.4 0.6 0.8 Value of time (RMB/min) 1 Profit (RMB) Social welfare (RMB) Figure 11: Effects of the value of time. 1.2 Journal of Advanced Transportation delay suffered by the passenger whose value of time is higher, resulting in a decrease in the maximum profit and social welfare. Therefore, the flexible bus company should determine the scope of target passengers in combination with the available service level in operation. With the change of the value of time, the optimal fares per unit distance of the two objectives range from 2.0 to 2.3 and 1.1 to 1.5, respectively, indicating good robustness when the value of time changes. 4. Conclusions With the goals of maximizing the expected profit and maximizing social welfare, the pricing model is constructed based on the cumulative prospect theory for the regional flexible bus service. The parameters of the model were calibrated through a stated preference survey, and two flexible bus cases were designed to analyze the performance of the model. First, we considered the passenger detour in the flexible bus pricing problem and explored the influence of uncertain detour time and fare on passengers’ mode choice probability. Second, we modeled the mutual influence among passengers and found that the certain passenger’s mode choice probability would affect the detour probability of other passengers. Thus, a calculation method for detour time distribution was proposed. The results showed that the detour time has a greater impact on the profit and social welfare of the system. More detour stops lead to a lower fare. As the travel distance increases, both the maximum expected profit and social welfare per unit distance increase. As the average detour time increases, the maximum expected profit and social welfare decrease. It is suggested that the flexible bus company may develop long-distance services and set a proper upper limit to the detour time to achieve higher profit. Besides, the passengers’ value of time and uncertainty also has a vital influence on the profit and social welfare of the system. The flexible bus company should determine the scope of target passengers in combination with the available service level in operation. With the change of the parameters, the optimal fares per unit distance vary in a small range. The pricing model has good robustness. There were some limitations to this study. When the area is small and the passengers are densely distributed, a detour time distribution can be calculated. But for few passengers in a large area, there may not be a specific detour time distribution. In addition, the current pricing model can only be used to handle static demand. How to dynamically price the flexible bus needs to be explored further. Data Availability The data used to support the findings of this study are available from the corresponding author upon request. Conflicts of Interest The authors declare that they have no conflicts of interest. 13 Acknowledgments The study was supported by the Shanghai Science and Technology Innovation Action Plan Project (20DZ1202805 and 21692110900), National Natural Science Foundation of China (nos. 72101186, 52131204, and 52002280). References [1] S. C. Ho, W. Y. Szeto, Y.-H. Kuo, J. M. Y. Leung, M. Petering, and T. W. H. Tou, “A survey of dial-a-ride problems: literature review and recent developments,” Transportation Research Part B: Methodological, vol. 111, pp. 395–421, 2018. [2] L. Wang, L. Zeng, W. Ma, and Y. Guo, “Integrating passenger incentives to optimize routing for demand-responsive customized bus systems,” Ieee Access, vol. 9, pp. 21507–21521, 2021. [3] Y. Li, X. Li, and S. Zhang, “Optimal pricing of customized bus services and ride-sharing based on a competitive game model,” Omega, vol. 103, p. 102413, 2021. [4] H. R. Sayarshad and H. Oliver Gao, “A scalable non-myopic dynamic dial-a-ride and pricing problem for competitive ondemand mobility systems,” Transportation Research Part C: Emerging Technologies, vol. 91, pp. 192–208, 2018. [5] I. Kaddoura, G. Leich, and K. Nagel, “The impact of pricing and service area design on the modal shift towards demand responsive transit,” Procedia Computer Science, vol. 170, pp. 807–812, 2020. [6] H. Gong, W. Jin, X. Hao, and Q. Luo, “Investigation into pricing game of customized city bus service,” Journal of South China University of Technology, vol. 45, no. 8, pp. 70–76, 2017. [7] E. Özkan, “Joint pricing and matching in ride-sharing systems,” European Journal of Operational Research, vol. 287, no. 3, pp. 1149–1160, 2020. [8] C. Yan, H. Zhu, N. Korolko, and D. Woodard, “Dynamic pricing and matching in ride hailing platforms,” Naval Research Logistics, vol. 67, no. 8, pp. 705–724, 2019. [9] X. Wang and R. Zhang, “Carpool services for ride sharing platforms: price and welfare implications,” Naval Research Logistics, 2021. [10] J. Bai, K. C. So, C. S. Tang, X. Chen, and H. Wang, “Coordinating supply and demand on an on-demand service platform with impatient customers,” Manufacturing & Service Operations Management, vol. 21, no. 3, pp. 556–570, 2019. [11] Y. Zhong, T. Yang, B. Cao, and T. C. E. Cheng, “On-demand ride-hailing platforms in competition with the taxi industry: pricing strategies and government supervision,” International Journal of Production Economics, vol. 243, p. 108301, 2022. [12] J. Ke, H. Yang, X. Li, H. Wang, and J. Ye, “Pricing and equilibrium in on-demand ride-pooling markets,” Transportation Research Part B: Methodological, vol. 139, pp. 411–431, 2020. [13] K. Zhang and Y. Nie, “To pool or not to pool: equilibrium, pricing and regulation,” Transportation Research Part B: Methodological, vol. 151, pp. 59–90, 2021. [14] T.-M. Choi, S. Guo, N. Liu, and X. Shi, “Optimal pricing in on-demand-service-platform-operations with hired agents and risk-sensitive customers in the blockchain era,” European Journal of Operational Research, vol. 284, no. 3, pp. 1031–1042, 2020. [15] C. Wu, S. Le Vine, A. Sivakumar, and J. Polak, “Dynamic pricing of free-floating carsharing networks with sensitivity to travellers’ attitudes towards risk,” Transportation, pp. 1–24, 2021. 14 [16] D. Kahneman and A. Tversky, “Prospect Theory: an analysis of decision under risk,” Econometrica, vol. 47, no. 2, pp. 263–291, 1979. [17] A. Tversky and D. Kahneman, “Advances in prospect theory: cumulative representation of uncertainty,” Journal of Risk and Uncertainty, vol. 5, no. 4, pp. 297–323, 1992. [18] K. V. Katsikopoulos, Y. Duse-Anthony, D. L. Fisher, and S. A. Duffy, “Risk attitude reversals in drivers’ route choice when range of travel time information is provided,” Human Factors: The Journal of the Human Factors and Ergonomics Society, vol. 44, no. 3, pp. 466–473, 2002. [19] S. Ghader, A. Darzi, and L. Zhang, “Modeling effects of travel time reliability on mode choice using cumulative prospect theory,” Transportation Research Part C: Emerging Technologies, vol. 108, pp. 245–254, 2019. [20] Y. Y. Liu, W. M. Liu, Y. M. Hu, and J. Li, “Pricing model of traffic demand management based on cumulative prospect theory,” in Proceedings of the 2010 8th World Congress on Intelligent Control and Automation, pp. 5175–5180, Jinan, 7-9 July 2010. [21] H. Xu, Y. Lou, Y. Yin, and J. Zhou, “A prospect-based user equilibrium model with endogenous reference points and its application in congestion pricing,” Transportation Research Part B: Methodological, vol. 45, no. 2, pp. 311–328, 2011. [22] D. Koffman, “Operational experiences with flexible transit services,” 2004. [23] Z. Li, D. A. Hensher, and J. M. Rose, “Willingness to pay for travel time reliability in passenger transport: a review and some new empirical evidence,” Transportation Research Part E: Logistics and Transportation Review, vol. 46, no. 3, pp. 384–403, 2010. [24] K. A. Small, “The scheduling of consumer activities: work trips,” The American Economic Review, vol. 72, no. 3, pp. 467–479, 1982, http://www.scientific.net/SSP.23-24.117. [25] K. A. Small, R. B. Noland, X. Chu, and D. L. Lewis, Valuation of Travel-Ime Savings and Predictability in Congested Conditions for Highway User-Cost Estimation, Transportation Research Board, Washington Dc, 1999. [26] R. Batley and J. N. Ibáñez, “Randomness in preference orderings, outcomes and attribute tastes: an application to journey time risk,” Journal of Choice Modelling, vol. 5, no. 3, pp. 157–175, 2012. Journal of Advanced Transportation
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Understanding carbon dioxide capture on metal–organic frameworks from first-principles theory: The case of MIL-53(X), with X = Fe3+, Al3+, and Cu2+
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Understanding carbon dioxide capture on metal–organic frameworks from first- principles theory: The case of MIL-53(X), with X = Fe3+, Al3+, and Cu2+ Cite as: J. Chem. Phys. 155, 024701 (2021); https://doi.org/10.1063/5.0054874 Submitted: 22 April 2021 • Accepted: 18 June 2021 • Published Online: 09 July 2021 Cite as: J. Chem. Phys. 155, 024701 (2021); https://doi.org/10.1063/5.0054874 Submitted: 22 April 2021 • Accepted: 18 June 2021 • Published Online: 09 July 2021 Giane B. Damas, Luciano T. Costa, Rajeev Ahuja, et al. ABSTRACT Metal–organic frameworks (MOFs) constitute a class of three-dimensional porous materials that have shown applicability for carbon dioxide capture at low pressures, which is particularly advantageous in dealing with the well-known environmental problem related to the carbon dioxide emissions into the atmosphere. In this work, the effect of changing the metallic center in the inorganic counterpart of MIL-53 (X), where X = Fe3+, Al3+, and Cu2+, has been assessed over the ability of the porous material to adsorb carbon dioxide by means of first-principles theory. In general, the non-spin polarized computational method has led to adsorption energies in fair agreement with the experimental outcomes, where the carbon dioxide stabilizes at the pore center through long-range interactions via oxygen atoms with the axial hydroxyl groups in the inorganic counterpart. However, spin-polarization effects in connection with the Hubbard corrections, on Fe 3d and Cu 3d states, were needed to properly describe the metal orbital occupancy in the open-shell systems (Fe- and Cu-based MOFs). This methodology gave rise to a coherent high-spin configuration, with five unpaired electrons, for Fe atoms leading to a better agreement with the experimental results. Within the GGA+U level of theory, the binding energy for the Cu-based MOF is found to be Eb = −35.85 kJ/mol, which is within the desirable values for gas capture applications. Moreover, it has been verified that the adsorption energetics is dominated by the gas–framework and internal weak interactions. © 2021 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). https://doi.org/10.1063/5.0054874 Understanding carbon dioxide capture on metal–organic frameworks from first-principles theory: The case of MIL-53(X), with X = Fe3+, Al3+, and Cu2+ Cite as: J. Chem. Phys. 155, 024701 (2021); doi: 10.1063/5.0054874 Submitted: 22 April 2021 • Accepted: 18 June 2021 • Published Online: 9 July 2021 AFFILIATIONS 1 Materials Theory Division, Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden 2Department of Physics Chemistry and Biology Linköping University 58330 Linköping Sweden 1 Materials Theory Division, Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden 2Department of Physics, Chemistry and Biology, Linköping University, 58330 Linköping, Sweden 3MolMod-CS- Department of Physical-Chemistry, Campus Valonguinho, Institute of Chemistry, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil 4Department of Engineering and Physics, Karlstad University, 65188 Karlstad, Sweden Fluminense Federal University, Niterói, Rio de Janeiro, Brazil 4Department of Engineering and Physics, Karlstad University, 65188 Karlstad, Sweden a)Authors to whom correspondence should be addressed: giane.benvinda.damas@liu.se and moyses.araujo@physics.uu.se a)Authors to whom correspondence should be addressed: giane.benvinda.damas@liu. a)Authors to whom correspondence should be addressed: gia a)Authors to whom correspondence should be addressed: giane.benvinda.damas@liu.se and moyses.araujo@physics.uu.se ARTICLES YOU MAY BE INTERESTED IN A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu The Journal of Chemical Physics 132, 154104 (2010); https://doi.org/10.1063/1.3382344 Deep learning combined with IAST to screen thermodynamically feasible MOFs for adsorption-based separation of multiple binary mixtures The Journal of Chemical Physics 154, 234102 (2021); https://doi.org/10.1063/5.0048736 Machine learning using host/guest energy histograms to predict adsorption in metal– organic frameworks: Application to short alkanes and Xe/Kr mixtures The Journal of Chemical Physics 155, 014701 (2021); https://doi.org/10.1063/5.0050823 A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu The Journal of Chemical Physics 132, 154104 (2010); http J. Chem. Phys. 155, 024701 (2021); https://doi.org/10.1063/5.0054874 155, 024701 © 2021 Author(s). J. Chem. Phys. 155, 024701 (2021); https://doi.org/10.1063/5.0054874 © 2021 Author(s). © 2021 Author(s). The Journal of Chemical Physics ARTICLE scitation.org/journal/jcp I. INTRODUCTION have found that strong interactions between water molecules and the framework lead to enhanced water adsorption that could be beneficial or not for gas capture.24 In another work, Siegelman et al. have found an improvement in efficiency by an amine-functionalized Mg-based MOF due to hydrogen-bonding interactions between water molecules and carbamate nitrogen atoms, which favor carbon dioxide binding.37 However, it is more common that trace amounts of water can exert a negative impact on the adsorption capacity.33 For instance, Liu et al.33 have verified a decrease in carbon dioxide adsorption from 3.74 to 2.69 mol/kg in a Ni-based MOF with water traces besides the negative effect on the CO2/N2 selectivity.l i In general, the presence of open metal sites with appropri- ate geometry and pore size in metal–organic frameworks is directly associated with high adsorption capacity and selectivity.12,28 Addi- tionally, the material should present high heat or enthalpy of adsorption for good performance at low pressures.28 This important macroscopic quantity is directly associated with the gas–framework interaction strength, which is expected to be strong enough to main- tain the latter inside the pore through weak interactions at the end of the process and also provide a suitable post-processing based cat- alytic reaction where the activated carbon dioxide can be converted in raw materials.29 On the other hand, the ideal condition of process reversibility is maintained with intermediate values for this quantity. y This work aims at understanding the influence of the metal- lic center from MIL-53 (X), where X = Fe3+, Al3+, or Cu2+, on the carbon dioxide capture. Such analysis is performed on a ther- modynamic point of view by means of first-principles calculations based on density functional theory (DFT). The outcomes suggest that the organic counterpart of the metal–organic framework also participates in the adsorption energetics as the oxygen atoms in this region and hydroxyl groups interact in a different extent in each material. In general, the non-spin polarized results have shown consistency to describe the energetics for these systems, but the open shell configuration exhibited by Fe- and Cu-based MOFs is better described with inclusion of such effects. Additionally, the Hubbard corrections have led to a consistent description of the atomic magnetic moment for the metallic center in these systems, a property that has been found to affect severely the adsorption energetics. I. INTRODUCTION It is important to emphasize that further developments in the field are still made necessary in order to turn these mate- rials competitive in an industrial point of view. In this context, different strategies have been proposed to improve the perfor- mance of metal–organic frameworks for gas capture applications. In analogy with the amine-based solvents that are traditionally employed in post-combustion methods, the functionalization by amine groups has been widely considered to increase the storage capacity and selectivity by improving the interaction strength with carbon dioxide.13,27,28,30 For instance, Hu et al.13 have evaluated the effects of anchoring alkylamine groups in unsaturated Cr3+ cen- ters of MOF-101 at room temperature conditions. In their series, the diethylenetriamine-functionalized MOF exhibits the best CO2 uptake (3.5 mmol g−1) even with a significant reduction in the sur- face area. In another work, 2-aminoterephthalic acid has been tested as an organic linker in an amino-functionalized Cu-based MOF to increase the gas uptake to 5.85 mmol g−1.15 Methacrylamides have also been employed to enhance the carbon dioxide capture in MOFs.31 I. INTRODUCTION capture and storage (CCS) program4–6 has different technologies to partially deal with the carbon emissions, finding applications in several industrial installations that include thermodynamic power plants and steel production. In the post-combustion approach, car- bon dioxide is captured from the gas stream due to its affinity to amine-based solutions.7–9 In general, these compounds present kinetically favored reactivity with carbon dioxide, as well as low solubility of hydrocarbon compounds that are quite interesting.10 Nonetheless, the low selectivity in the presence of sulfur dioxide and the high energy necessary for solvent regeneration represent a The World Meteorological Organization (WMO) has pointed out an expected average temperature of 1.5 ○C higher than the pre- industrial levels in less than 35 years, as the most abundant green- house gas, carbon dioxide, has reached an increase in 3.3 ppm (0.83%) in one year of analysis, which corresponds to an overall increase of about 145% compared to the pre-industrial levels.1 In this context, great efforts are necessary from different sectors of our society for a further change in the current scenario.2,3 The carbon J. Chem. Phys. 155, 024701 (2021); doi: 10.1063/5.0054874 © Author(s) 2021 155, 024701-1 155, 024701-1 The Journal of Chemical Physics The Journal of Chemical Physics ARTICLE scitation.org/journal/jcp major problem for capture-related applications.11 Thus, the devel- opment and synthesis of new chemical absorbers that can address these problems without losing the capacity for gas adsorption are highly desired.6 chloride groups. Although still containing amine groups in the struc- ture, the extra adsorption sites promote an increase of about ∼20% in gas uptake by the resulting MOFs when compared to the initial amine-functionalized material.32 g y Metal–organic frameworks (MOFs) constitute a class of three- dimensional porous materials formed by interconnecting inorganic and organic counterparts, which has found large applicability in this field.12–16 In particular, the MIL-53 frameworks comprise an inorganic region formed by the metallic centers connecting oxy- gen atoms from hydroxyl groups (axial positions) or benzene dicar- boxylate (BDC) ligands (equatorial positions) in an octahedral con- figuration.17–19 In recent years, the applicability of this series has been widely evaluated by means of experimental14,18,20–25 and the- oretical methods17,26 for gas adsorption, including carbon diox- ide,14,18,20–23,26,27 methane,18,23,25,26 and hydrogen sulfide.24 Traces of water can also affect the adsorption capacity and selectivity for carbon dioxide capture in a gas mixture.33–36 Huang et al. II. COMPUTATIONAL METHODS The applicability of metal–organic frameworks to gas capture at low pressures has direct association with certain macroscopic properties, such as adsorption capacity and heat/enthalpy of adsorption.12,28 The latter has a thermodynamic definition that requires the inclusion of thermal corrections to the total energies for its full assessment, i.e., zero point energies and thermal effects acting over the internal energy of each system, but the main contributing term is the total energy itself.17 Hence, variations in this property prior and posterior to adsorption give a reliable estimation of the enthalpy of reaction/adsorption that is crucial to evaluate how good the material is for gas capture. From a microscopic standpoint, such variations are generally dictated by the interaction strength between the metal–organic framework and the guest molecule (carbon dioxide), namely, the binding energy (Eb). Furthermore, pore functionalization by other chemical groups, including methyl, hydroxyl, and carboxyl groups, has been reported.12,27,28 In this sense, Torrisi et al.27 have shown that embed- ding carboxyl and hydroxyl groups into MIL-53(Al3+) is particu- larly advantageous for gas capture applications in comparison to amine functionalities. Nonetheless, anchoring chemical groups in metal–organic frameworks is not always straightforward in a practi- cal point of view since the synthesis conditions, given by high pres- sures and temperatures, do not favor the anchoring process of sev- eral chemical functionalities.32 To overcome this issue, Yan et al.32 have initially synthesized the template with active amine groups that were further substituted by the desired acetic acid and trimesoyl Therefore, the heat/enthalpy of adsorption has been assessed by calculating the binding energy (Eb) of the solid-state system within the framework of the density functional theory (DFT) as imple- mented in the Vienna Ab-Initio Simulation Package (VASP).38 Fur- ther details on the computational methodology for modeling the metal–organic framework are given in Subsections II A and II B. J. Chem. Phys. 155, 024701 (2021); doi: 10.1063/5.0054874 © Author(s) 2021 155, 024701-2 155, 024701-2 The Journal of Chemical Physics The Journal of Chemical Physics ARTICLE scitation.org/journal/jcp A. Bulk structures Fe, Al, Cu, C, O, and H atoms. As the semi-local generalized gradi- ent approximation (GGA) functional fails to describe the bandgap of semiconducting materials, Hubbard corrections have been applied on Fe 3d and Cu 3d states through spin-polarized static calculations within the tetrahedron method with Blöchl corrections. The partial occupancies for each orbital have also been determined by using the Gaussian smearing for visual analysis of the orbital hybridization. Here, the assessment of the electronic structure is basically intended to complement the material description. To model the metal–organic frameworks here under consid- eration, the crystallographic data of MIL-53 (Fe3+) reported by Millange et al have been used.39 The original structure has been modified to include hidden hydrogen atoms at the inorganic region, more specifically at the oxygen atoms that are displaced in axial posi- tions related to the metallic center.17 Furthermore, it was necessary to remove the water molecules lying inside the pores in order to activate the material for gas adsorption (Fig. 1).40 The Perdew–Burke–Ernzerhof (PBE) functional41 was the functional of choice to treat the exchange-correlation potential in the initial solid-state calculations, as it has provided good agree- ment with experimental data obtained for the evaluation of similar thermodynamic properties in previous reports.42–45 In the current study, the ionic relaxations were carried out until the total ener- gies reached the convergence criterion of 1.0 × 10−3 eV. Dispersion effects and weak interactions were taken into account by including the D3-Grimme corrections46 in all steps. The plane wave-basis set was defined with a cutoff energy of 800 eV after convergence tests in the sampled region (400–1000 eV). The Brillouin zone was sam- pled by a 2 × 2 × 4 Monkhorst–Pack k-point mesh. Spin-polarization effects were further considered for the frameworks with an open shell configuration [MIL-53 (X), where X = Fe3+ and Cu2+]. Alterna- tively, the lattice parameters have been fully relaxed for these systems as displayed in Table S1 of the supplementary material. A. Bulk structures In order to evaluate how the metallic center affects the ability of a non-functionalized metal–organic framework to capture carbon dioxide, we have considered the bulk structure from MIL-53 (Fe3+) with a diamond-shape pore, also called the narrow pore form. This material crystallizes in a P21/c space group with unit cell dimensions given by a = 19.32 Å, b = 15.04 Å, c = 6.84 Å, and β = 96.3○. Initially, lattice parameters have been constrained during the relaxation step in order to maintain the spatial group symmetry of the crystalline structure. Table S1 shows that the optimization of lattice parameters leads to a slight decrease of ∼1–2 Å of the b lattice parameter and variation of <2○in the lattice angles for these systems that are not expected to affect the adsorption thermodynamics upon expansion into the 2 × 2 supercell. g An interesting point is that μ for oxygen atoms is slightly increased at the hydroxyl groups in the Cu-based MOF (∼0.3 μb/atom) in comparison with the Fe-based system (<0.2 μb/atom), which is not verified for the oxygen atoms connected to the BDC ligands. Although the Cu-based MOF does not exhibit a significant change in the atomic μ for the metallic centers regarding the level of theory, the iron-based material does have a significant variation in this property (1.0–4.0 μb) within the PBE level, which would lead to Fe3+ ions displaying different electronic configurations along the symmetric crystal environment. Such inaccuracy to describe the Fe-based MOF electronic structure could affect the thermodynamic properties if this effect is not propagated upon addition of the carbon dioxide molecule in the further steps. p In MIL-53 (Fe3+), the inorganic counterpart formed by the iron metallic center is linked to the benzene dicarboxylate (BDC) ligands via oxygen atoms that are located in equatorial positions. In the axial positions, the hydroxyl groups form a region that can interact with the guest molecule as the hydrogen atoms are pointed out vertically to the pore center, while not presenting any steric hindrance. In this sense, the vertical distance between hydrogen atoms from different inorganic counterparts has been calculated as dH–H = 5.20–5.40 Å, with iron atoms from adjacent parts being distanced by 19.32 Å. A. Bulk structures Replacing the metallic center by aluminum or copper in MIL-53 (Al) and MIL-53 (Cu) does not promote variations in the pore width (∼19.3 Å), but its size is diminished for the aluminum case (dH–H = 5.11 Å). Additionally, there is a shortage in the Al–O chemical bond of about ∼0.2 Å in comparison to Fe–O or Cu–O, which might be resultant from a stronger interaction between the metallic center and the oxygen connecting the organic counterpart. At this point, it is necessary to emphasize that MIL-53 (Al3+) does not present the same crystal structure as the iron-based material; thus, it is an approximate model for this study.17 p For MIL-53 (Fe3+), the optimum value for the Hubbard param- eter on Fe 3d states was estimated to be U = 7 eV and J = 1 eV to give a theoretical bandgap (Eg = 2.20 eV) that shows fair agree- ment with the experimental report.47 As displayed in Fig. 2(a), this system has the valence band maximum (VBM) mainly com- posed of O 2p orbitals connecting to the metallic center, which persists until −2.6 eV. In the valence band, the spin-up contri- butions from Fe 3d states have a rising contribution from ∼−0.3 to −0.7 eV, but the conduction band minimum (CBM) is basi- cally determined by the position of the spin-down contributions from these atoms. Fingerprints from C–H and O–H bonds can be easily identified in the H 1s plot [Fig. 2(a)- bottom] with four clear peaks in the interval from −1.8 to −5.7 eV that match well with C 2p states and O 2p states that are present in the same interval. In Fig. S1(b), the calculated bandgap for MIL-53 (Al3+) is Eg = 3.23 eV, which also shows good agreement with the experi- mental value reported by Guo et al. (Eexp = 3.56 eV).51 In the same work, the authors have found that this material has an absorption B. Structure model 155, 024701 (2021); doi: 10.1063/5.0054874 © Author(s) 2021 155, 024701-3 155, 024701-3 © Author(s) 2021 The Journal of Chemical Physics The Journal of Chemical Physics The Journal of Chemical Physics ARTICLE scitation.org/journal/jcp 0.01 and 0.03 eV/Å for the pore structure and the guest molecule, respectively. The GGA+U relaxations have been carried out using U = 7 eV and J = 1 eV as Hubbard parameters on Fe 3d and Cu 3d states, while employing the same energy convergence criteria for the electronic/ionic steps. structural parameters that are optimized during the relaxation pro- cess, i.e., the ionic positions are always considered but the lattice parameters are usually kept fixed throughout the relaxation. i MIL-53 (Fe3+) has shown photoactivity in the visible light region with an experimental optical gap of 2.64 eV, which corre- sponds to an absorption edge at λ = 470 nm.47 Furthermore, the authors point out that the maximum absorption at λ = 220 nm is due to the ligand to metal charge transfer, O (II) →Fe (II).47 Figure 2 and Fig. S1 depict the density of states of MIL-53 (X), where X = Fe3+, Al3+, and Cu2+, as obtained using the Gaussian smear- ing and tetrahedron method with Blöchl corrections, respectively. The latter choice is justified by the semiconducting nature of these materials, which requires such a methodology for an appropriate description of their intrinsic bandgaps, whereas the Gaussian smearing facilitates the plot visualization. The binding energy Eb of the adsorbed species to the frame- work has been calculated by subtracting the total energy prior and posterior to the adsorption, i.e., Eb = EMOF−gas −(EMOF + Egas), (1) (1) where EMOF-gas is the total energy of the gas–framework system and the last terms correspond to the individual total energies before adsorption. Zero-point energies and thermal corrections are not considered in this definition. Effects of spin-polarization and Hub- bard corrections (GGA+U) on Fe 3d and Cu 3d states over the quantity expressed by Eq. (1) have also been evaluated for the Fe- and Cu-based metal–organic frameworks. For Fe- and Cu-based metal–organic frameworks, the GGA+U methodology has been used to deal with the self-interaction prob- lem from the GGA approximation to density functional theory that often leads to an underestimated bandgap.48–50 In this sense, these calculations were performed in a static mode after spin-polarized ionic relaxation within the PBE level of theory. B. Structure model These open-shell systems present an octahedral d orbital splitting with the electron occupancy in Cu d-orbitals expressed as (t3↑↓ 2g e2↑,1↓ g ), whereas the magnetic moment (μ) for Fe3+ (4.5 μb/atom) suggests a high-spin state with electron occupancy given by (t3↑ 2ge2↑ g ). B. Structure model The gas capture process has been evaluated by expanding the initial bulk structure into a 2 × 2 supercell aiming to avoid adsor- bate interactions with their respective images in the periodic system. Initially, it has been assumed that the pore structures do not vary in a significant way upon gas uptake by allowing partial relaxation of the system, i.e., the ionic positions. This is an oversimplifica- tion that is expected to describe the gas adsorption process in a proper way. Nonetheless, we have also considered eventual changes in the crystal lattice by enabling full relaxation of the system. These results are briefly discussed in this publication. In the former case, the partial relaxations were performed within the Γ-point with a plane-wave cutoff energy of 550 eV. A tighter energy convergence criterion has been applied for electronic/ionic steps (1.0 × 10−5/1.0 × 10−4 eV) in order to guarantee that the global minimum on the potential energy surface (PES) has been reached. The final atomic forces over the metal–organic frameworks are found to be less than The electronic structure has been attained by calculating the density of states (DOS) and its projected components (pDOS) on FIG. 1. Bulk structure of MIL-53 (Fe3+) after ionic position relaxation at the PBE/800 eV level of theory including spin-polarization effects. In detail, it is possible to observe the narrow pore structure of this material. The red, gray, and white spheres correspond to oxygen, carbon, and hydrogen atoms, respectively, whereas the golden sphere is representative of Fe, Al, or Cu. Code: VASP. FIG. 1. Bulk structure of MIL-53 (Fe3+) after ionic position relaxation at the PBE/800 eV level of theory including spin-polarization effects. In detail, it is possible to observe the narrow pore structure of this material. The red, gray, and white spheres correspond to oxygen, carbon, and hydrogen atoms, respectively, whereas the golden sphere is representative of Fe, Al, or Cu. Code: VASP. FIG. 1. Bulk structure of MIL-53 (Fe3+) after ionic position relaxation at the PBE/800 eV level of theory including spin-polarization effects. In detail, it is possible to observe the narrow pore structure of this material. The red, gray, and white spheres correspond to oxygen, carbon, and hydrogen atoms, respectively, whereas the golden sphere is representative of Fe, Al, or Cu. Code: VASP. J. Chem. Phys. B. Electronic structure edge at λ = 348 nm; therefore, it would not exhibit activity in the visible region for eventual photocatalytic purposes. Here, it is veri- fied that the valence band is formed mainly of O 2p and C 2p states from the top (−0.3 eV) until −2.3 eV. Al 3p states do not participate in the VBM or CBM composition, which are prominent just in the range of −2.1 to −7.1 eV with very low density of states (<2.6 den- sity of states/eV). In the VBM, a very low contribution from Al 3s states (0.11 DOS/eV) can be seen at −2.9 eV. This is the reason for the large bandgap shown by this material, since the CBM is formed by the overlapping of 2p states from carbon and oxygen atoms that lie much higher in energy than the unoccupied d states from Fe and Cu atoms. Here, the C–H and O–H bonds are verified upon orbital overlapping from −1.74 to −10.0 eV with four major peaks that are shifted in about +0.25 eV compared to the Fe-based MOF. p As displayed in Fig. 2(c), MIL-53 (Cu2+) has a similar den- sity of states profile shown by the iron-based system with Cu 3d unoccupied states lying much lower in energy compared to Fe 3d states. Therefore, the overlapping with unoccupied states from oxy- gen atoms is promoted initially at +0.23 eV (1.4 eV lower than Fe-based MOF) to significantly reduce the bandgap. On the other hand, carbon unoccupied orbitals will just appear with a higher intensity at about +3.0 eV. This material has a calculated bandgap of Eg = 0.83 eV using U = 7 eV and J = 1 eV for Cu 3d states [see Fig. S1(c)]. p Mahdipoor et al. have previously determined the absolute heat of adsorption for MIL-53 (Fe3+) in 58.7 kJ/mol by experi- mental methods.52 Table I (second column) indicates that Eb lies between −47.60 and −73.42 kJ/mol for this material, which gives an overestimation of ∼25% for the most favorable configuration (site 1). In this system, the final configuration shows a small angular shift for a better (CO2) O⋅⋅⋅H (MOF) interaction at ∼1.97 Å. Such an interaction does not alter the O–H bond (∼0.98 Å) from the hydroxyl groups or the C=O bond (1.18 Å), a typical behavior for weak van der Waals interactions. B. Electronic structure This analysis has been primarily considered to validate the density functional theory methodology, but also to establish the J. Chem. Phys. 155, 024701 (2021); doi: 10.1063/5.0054874 © Author(s) 2021 155, 024701-4 155, 024701-4 © Author(s) 2021 The Journal of Chemical Physics ARTICLE scitation.org/journal/jcp FIG. 2. Density of states obtained for the metal–organic frameworks under investigation at the level of theory: PBE/800 eV for MIL-53 (Al3+) and GGA+U/800 eV, with U = 7 eV on Fe 3d or Cu 3d states of MIL-53 (X = Fe3+, Cu2+). Code: VASP /Gaussian smearing method with σ = 0.1. The Journal of Chemical Physics scitation.org/journal/jcp FIG. 2. Density of states obtained for the metal–organic frameworks under investigation at the level of theory: PBE/800 eV for MIL-53 (Al3+) and GGA+U/800 eV, with U = 7 eV on Fe 3d or Cu 3d states of MIL-53 (X = Fe3+, Cu2+). Code: VASP /Gaussian smearing method with σ = 0.1. FIG. 2. Density of states obtained for the metal–organic frameworks under investigation at the level of theory: PBE/800 eV for MIL-53 (Al3+) and GGA+U/800 eV, with U = 7 eV on Fe 3d or Cu 3d states of MIL-53 (X = Fe3+, Cu2+). Code: VASP /Gaussian smearing method with σ = 0.1. FIG. 2. Density of states obtained for the metal–organic frameworks under investigation at the level of theory: PBE/800 eV for MIL-53 (Al3+) and GGA+U/800 eV, with U = 7 eV on Fe 3d or Cu 3d states of MIL-53 (X = Fe3+, Cu2+). Code: VASP /Gaussian smearing method with σ = 0.1. that are connected to the metallic center in the axial positions. At site (2), the interaction occurs with the ligand carbon and hydrogen atoms through the oxygen atom. At site (3), the molecule is expected to move freely inside the pore to interact via carbon or oxygen atoms. Horizontal interactions with hydrogen from the BDC ligand have been considered at site (4). Finally, at site (5), the guest molecule has been placed to interact with both inorganic (via hydroxyl groups) and organic (via carbon) counterparts. Table I contains the gas–framework binding energies (Eb) calculated via Eq. (1) for all configurations (in kJ/mol). Inclusion of spin-polarization has been considered at the third and fourth columns, in which the latter column is estimated within the GGA+U level of the- ory. The experimental values are available in the last column for comparison. B. Electronic structure Thus, one should not expect any changes in the electronic structure of this system since there is no orbital hybridization between O 2p (CO2) and H 1s orbitals (-OH group). Here, the comparison between experiment/calculation methods is given with the absolute values for heat of adsorption. C. Gas capture Figure 3 displays the adsorption sites (labeled by different num- bers) here under consideration for CO2 capture. At site (1), the interaction takes place via hydrogen atoms from hydroxyl groups J. Chem. Phys. 155, 024701 (2021); doi: 10.1063/5.0054874 © Author(s) 2021 155, 024701-5 155, 024701-5 scitation.org/journal/jcp FIG. 3. Initial configurations for CO2 adsorption inside the MOF structures under investigation: the interaction takes place vertically in 1, 2, and 5, whereas in 3 (in detail) and 4, the carbon dioxide molecule has been placed in a horizontal position. The red, gray, and white spheres correspond to oxygen, carbon, and hydrogen atoms, respectively, whereas the golden sphere is representative of Fe, Al or Cu. FIG. 3. Initial configurations for CO2 adsorption inside the MOF structures under investigation: the interaction takes place vertically in 1, 2, and 5, whereas in 3 (in detail) and 4, the carbon dioxide molecule has been placed in a horizontal position. The red, gray, and white spheres correspond to oxygen, carbon, and hydrogen atoms, respectively, whereas the golden sphere is representative of Fe, Al or Cu. FIG. 3. Initial configurations for CO2 adsorption inside the MOF structures under investigation: the interaction takes place vertically in 1, 2, and 5, whereas in 3 (in detail) and 4, the carbon dioxide molecule has been placed in a horizontal position. The red, gray, and white spheres correspond to oxygen, carbon, and hydrogen atoms, respectively, whereas the golden sphere is representative of Fe, Al or Cu. (Eb = −189.58 to −245.43 kJ/mol). In order to investigate the under- lying reasons for such a discrepancy, the atomic magnetic moment (μ) at the metallic site has been evaluated for each case (see Table S2). The supercell prior to adsorption has ∼1–3 unpaired electrons at the It is interesting to note that applying spin-polarization effects, within the DFT/GGA theory level (third column), does not improve the theory–experiment agreement, instead leading to an even more significant overestimation in terms of absolute values TABLE I. Binding energies (Eb) for several possible configurations upon carbon dioxide adsorption within the GGA level without spin-polarized effects (second column, ISPIN = 1), as well as with its inclusion (third column, ISPIN-2). GGA+U values correspond to spin-polarized calculations with U = 7 eV and J = 1 eV on Fe 3d or Cu 3d states. C. Gas capture S2 (a) and (b) illus- trate the final structures after ionic relaxation with the experimental result than that found by previous works.17,27i metallic center (μ = 1.0–2.7 μB), but the introduction of the guest molecule promotes oscillations in the electron occupancy across the framework for all sites. As a result, the total magnetization does not remain constant in the series, even with multiple reoptimizations being carried out after the convergence is reached. These data clearly indicate the lack of consistency in the GGA level of theory to describe the open shell configuration of these frameworks, i.e., to find the correct minimum energy configuration in the potential energy surface, since the gas capture does not involve the metallic center in a direct way to justify the change in its electronic structure. The Cu-based MOF has site (1) as the most favorable config- uration within the PBE level of theory, with Eb = −39.80 kJ/mol in the non-spin polarized case. The final geometry can be visualized in Figs. S3(a) and S3(b), where the guest molecule is also rotated in rela- tion to site (1) in a similar position to that verified for the Fe-based MOF. Here, it is remarkable that the inclusion of spin-polarization effects provides a smoother trend with Eb = −37.49 to −47.36 kJ/mol in comparison with the Fe-based MOF. This can be associated with the lower number of unpaired electrons in the Cu-based MOF that approximates the solution to the non-spin polarized case, but it still provides a different chemical trend for this framework series. On the other hand, μ remains constant upon addition of car- bon dioxide within the GGA+U approximation as displayed in the fourth column in Table S2. In this case, the use of Hubbard cor- rections has returned Eb = −47.13 kJ/mol, which has an agreement of 80.3% with the experimental reported value.52 The total magne- tization determined for this material (mag = 80.00 μB) establishes a coherent high spin configuration with five unpaired electrons for each Fe atom. Changes in the U parameter (U = 6 and 8 eV) have been tested for better tuning of Eb, but no significant improvement has been observed (<1 kJ/mol) for site (1). C. Gas capture Note that the comparison between the heat of adsorption and Eb, which is based on the total energy variation prior and posterior to the adsorption, is held using the absolute values. In the last column, the absolute values of heat of adsorption are taken from the literature. The boldfaces denote the most favorable Eb for each case. Binding energies (Eb, kJ/mol) GGA GGA+U Heat of adsorption Configuration ISPIN-1 ISPIN-2 ISPIN-2 (kJ/mol) MIL-53 (Fe3+) 1 −73.42 −242.04 −47.13 58.752 2 −69.57 −198.47 −38.19 3 −48.34 −189.58 −21.26 4 −47.60 −215.50 −29.11 5 −51.55 −245.43 −17.71 MIL-53 (Al3+) 1 −36.19 ⋅⋅⋅ 2 −35.61 ⋅⋅⋅ 3 −36.73 ⋅⋅⋅ 35.018 4 −34.17 ⋅⋅⋅ 5 −19.39 ⋅⋅⋅ MIL-53 (Cu2+) 1 −39.80 −42.87 −35.85 2 −28.34 −39.90 −32.19 3 −33.23 −46.97 −33.66 n/a. 4 −30.38 −47.36 −30.97 5 −29.71 −37.49 −34.18 J. Chem. Phys. 155, 024701 (2021); doi: 10.1063/5.0054874 155, 024701-6 © Author(s) 2021 The Journal of Chemical Physics ARTICLE scitation.org/journal/jcp FIG. 4. Final configurations for CO2 adsorption inside MIL-53 (Fe3+) after ionic relaxation. In (a), the most favor- able configuration at site 1 is shown, whereas the other systems are rep- resented in (b). Note: the position of the hydrogen (from -OH groups) slightly varies for each case. The red, gray, and white spheres correspond to oxygen, carbon, and hydrogen atoms, respec- tively, whereas the golden sphere is rep- resentative of Fe. scitation.org/journal/jcp FIG. 4. Final configurations for CO2 adsorption inside MIL-53 (Fe3+) after ionic relaxation. In (a), the most favor- able configuration at site 1 is shown, whereas the other systems are rep- resented in (b). Note: the position of the hydrogen (from -OH groups) slightly varies for each case. The red, gray, and white spheres correspond to oxygen, carbon, and hydrogen atoms, respec- tively, whereas the golden sphere is rep- resentative of Fe. FIG. 4. Final configurations for CO2 adsorption inside MIL-53 (Fe3+) after ionic relaxation. In (a), the most favor- able configuration at site 1 is shown, whereas the other systems are rep- resented in (b). Note: the position of the hydrogen (from -OH groups) slightly varies for each case. The red, gray, and white spheres correspond to oxygen, carbon, and hydrogen atoms, respec- tively, whereas the golden sphere is rep- resentative of Fe. functions applied on hydrogen atoms, using a different model for MIL-53 (Al3+) that is based on its crystallographic data.17 Thus, the present study shows better agreement, and Fig. C. Gas capture The main H⋅⋅⋅O interactions in MIL-53 (X), where X = Fe3+, Al3+, or Cu2+ before the gas adsorption. The red, gray, and white spheres correspond to oxygen, carbon, and hydrogen atoms, respectively, whereas the golden sphere is representative of Fe, Al, or Cu. Level of theory: PBE/non-spin polarized. electronic convergence that remains constant in the further steps until the ionic relaxation is finished. This is not verified for the PBE method, where the magnetization tuning along with the ionic relax- ation process could lead to different electronic structure descriptions for some systems. same final configuration as site (3) for Al and Cu] as the GGA+U methodology has not been employed for structural relaxation of the Al-based MOF. All relevant data are reported in Table II. It is noticeable that the vertical distance between hydrogen atoms from different inorganic counterparts d(H1⋅⋅⋅H2) increases in the order Fe < Al < Cu as the H–O bond in the hydroxyl group is bent toward the organic counterpart. Such geometrical distortion is an overall effect of the electrostatic attraction between hydrogen (H1) and the surrounding oxygen atoms connected to that counterpart. In MIL-53 (Cu2+), the attraction is more evident due to the shorter H1⋅⋅⋅O1 and H1⋅⋅⋅O2 distances (2.55 and 2.62 Å), while the (O1⋅⋅⋅H1⋅⋅⋅O2) angle is about 26○higher than that in the other MOFs. Nonetheless, these interactions are weakened upon gas adsorption, as indicated by the stretching of H1⋅⋅⋅O1 and H1⋅⋅⋅O2 distances to up to 2.98 Å (an increase of ∼0.4 Å) in MIL- 53 (Cu2+), which is a more significant variation than that observed for the other frameworks. Furthermore, the decrease of 56.4○in the a(O1⋅⋅⋅H1⋅⋅⋅O2) angle for this framework upon adsorption indicates a weakened interaction between the gas and the organic region. Albeit these frameworks have crystal structures that only dif- fer by the metallic center, it is noticeable that the Fe-based MOF has a binding energy (Eb) for carbon dioxide capture that is much higher than the other frameworks (see Table I). Such disparity is not explained by the gas–framework interaction strength since the inter- action distance remains unaltered (1.97–2.04 Å) regardless of the material. Moreover, the van der Waals nature of these interactions points out the inactivity of the metallic center in the gas adsorp- tion. Thus, we should account for other weak interactions inside the framework that could play a significant role in the adsorption energetics. C. Gas capture p In the GGA+U case, Eb = −35.85 kJ/mol is 7.0 kJ/mol lower than that predicted by the PBE method, suggesting a very simi- lar heat of adsorption for this material in comparison with MIL-53 (Al3+). The final magnetization in the supercell (mag = 32.00) is coherent with the presence of one unpaired electron in each metallic center (∼0.9 μB/atom) and a slight magnetization on O atoms from the metal–organic framework (∼0.1–0.3 μB). Hence, the presence of an unpaired electron confirms the Cu d9 electronic configuration arising from the Cu2+ oxidation state in these systems. Therefore, this methodology is consistent to determine the electronic config- uration for these materials prior and posterior to the adsorption, thus providing total energies that can be compared with each other. The method itself determines the correct magnetization in the first The absolute heat of adsorption measured by Bourrelly et al.18 (35 kJ/mol) is indicative of a much weaker gas–framework inter- action in MIL-53 (Al3+) in comparison with the Fe-based MOF (58.7 kJ/mol).52 This property has been properly described by our calculations, where the most favorable configuration (3) over- estimates the experimental value by only 1.73 kJ/mol (<5%, Eb = −36.73 kJ/mol). For matters of comparison, Ramsahye et al. have determined Eb = −41 kJ/mol for MIL-53 (Al3+) within the PW91 level of theory/double numerical basis set with polarization J. Chem. Phys. 155, 024701 (2021); doi: 10.1063/5.0054874 © Author(s) 2021 155, 024701-7 155, 024701-7 The Journal of Chemical Physics ARTICLE scitation.org/journal/jcp FIG. 5. The main H⋅⋅⋅O interactions in MIL-53 (X), where X = Fe3+, Al3+, or Cu2+ before the gas adsorption. The red, gray, and white spheres correspond to oxygen, carbon, and hydrogen atoms, respectively, whereas the golden sphere is representative of Fe, Al, or Cu. Level of theory: PBE/non-spin polarized. ARTICLE scitation.org/journal/jcp FIG. 5. The main H⋅⋅⋅O interactions in MIL-53 (X), where X = Fe3+, Al3+, or Cu2+ before the gas adsorption. The red, gray, and white spheres correspond to oxygen, carbon, and hydrogen atoms, respectively, whereas the golden sphere is representative of Fe, Al, or Cu. Level of theory: PBE/non-spin polarized. FIG. 5. The main H⋅⋅⋅O interactions in MIL-53 (X), where X = Fe3+, Al3+, or Cu2+ before the gas adsorption. The red, gray, and white spheres correspond to oxygen, carbon, and hydrogen atoms, respectively, whereas the golden sphere is representative of Fe, Al, or Cu. Level of theory: PBE/non-spin polarized. FIG. 5. C. Gas capture Subsection III D will address this point in detail. J. Chem. Phys. 155, 024701 (2021); doi: 10.1063/5.0054874 © Author(s) 2021 D. Structural analysis: The non-spin polarized case In the second column, the oxygen atoms (O1–O6) are located either at the organic counterpart (organic) or the gas molecule (CO2). Level of theory: PBE/non-spin polarized. TABLE II. Structural parameters given by atomic distances (d, in Å) and angle (a, in ○) of the main contributions to the gas adsorption energetics in MIL-53 (X), with X = Fe3+, Al3+, or Cu2+. In the second column, the oxygen atoms (O1–O6) are located either at the organic counterpart (organic) or the gas molecule (CO2). Level of theory: PBE/non-spin polarized MIL-53 (Fe3+) MIL-53 (Al3+) MIL-53 (Cu2+) Atomic distance (Å)/Angle(○) Oxygen Initial +CO2 Δd Initial +CO2 Δd Initial +CO2 Δd d(O1⋅⋅⋅H1) Organic 2.87 2.82 −0.05 2.90 2.85 −0.05 2.55 2.69 0.14 d(O2⋅⋅⋅H1) Organic 2.64 2.64 0.00 2.71 2.69 −0.02 2.62 2.98 0.36 d(O3⋅⋅⋅H1) Organic 2.71 2.95 0.14 2.68 2.89 0.21 3.12 2.97 −0.15 d(H1⋅⋅⋅H2) ⋅⋅⋅ 5.16 5.44 0.28 5.22 5.39 0.17 5.50 5.76 0.26 d(X–X) ⋅⋅⋅ 7.50 8.46 1.16 7.52 8.42 0.90 7.52 8.47 0.95 d(H1⋅⋅⋅O4) CO2 ⋅⋅⋅ 1.97 ⋅⋅⋅ ⋅⋅⋅ 1.98 ⋅⋅⋅ ⋅⋅⋅ 2.04 ⋅⋅⋅ d(H2⋅⋅⋅O5) CO2 ⋅⋅⋅ 1.97 ⋅⋅⋅ ⋅⋅⋅ 1.98 ⋅⋅⋅ ⋅⋅⋅ 2.05 ⋅⋅⋅ d(C1⋅⋅⋅O6) ⋅⋅⋅ ⋅⋅⋅ 2.88 ⋅⋅⋅ ⋅⋅⋅ 2.90 ⋅⋅⋅ ⋅⋅⋅ 2.81 ⋅⋅⋅ a(O1⋅⋅⋅H1⋅⋅⋅O2) Organic 114.6 115.1 0.5 112.0 113.2 1.2 138.9 82.5 −56.4 Eb (kJ/mol) −73.42 −36.73 −39.18 and with a CO2 binding energy of −47.13 kJ/mol in good agreement with the experimental finding for heat of adsorption. It should be pointed out that our thermodynamics assessment includes only the total energy contribution for the reaction enthalpy, i.e., temperature- dependent contributions to the internal energy, zero-point energy, and pV term are not included. Therefore, the agreement with the experimental outcome could be further improved if such contri- butions are included and specific thermodynamics conditions are properly simulated. However, it lays beyond the scope of the cur- rent study. In the case of the Cu-based MOF, we have obtained a CO2 binding energy of −35.85 kJ/mol. The latter is similar to the one obtained for the Al-based MOF, viz., −36.73 kJ/mol. These results indicate that Cu-based MIL-53 is a promising framework for CO2 capture applications. Concerning the structure, the CO2 guest molecule is stabilized within the MOF pore center through weak interactions with the hydroxyl groups of the inorganic counterpart, which shows the relevance of the coordinating molecule on the metal site. These results provide insights for future design of suitable MOF compounds for CO2 capture and storage. IV. CONCLUSIONS In the current study, we have investigated the effect of vary- ing the metallic center in the inorganic counterpart of MIL-53 (X), where X = Fe3+, Al3+, Cu2+, on the carbon dioxide adsorp- tion by using first-principles methods. The relevance of applying spin-polarization and Hubbard corrections (GGA+U method) to describe the electronic structure and gas adsorption energetics has been investigated. The Hubbard parameters for Cu- and Fe-based MOFs have been initially estimated through electronic structure assessment, in which the values of U = 7 eV and J = 1 eV are found to be appropriate to treat the Fe d and Cu d states. Within this theory level, MIL-53 (Cu2+) has a calculated bandgap of 0.83 eV, whereas MIL-53 (Fe3+) and MIL-53 (Al3+) display bandgaps of 2.20 and 3.23 eV, respectively, in fair agreement with experimental reports. D. Structural analysis: The non-spin polarized case The process of gas accommodation inside the framework pore promotes an increase in the distance between metallic centers in about d(X–X) = 0.9–1.2 Å. As this distance is decreased in the adja- cent unit cells by ∼0.5 Å, it is suggested that the presence of the guest molecule slightly opens the pore, whereas the flexibility of this model is clarified. Thus, the wider space opened between dif- ferent inorganic regions in MIL-53 (Cu2+) could slightly decrease the interaction strength with the guest molecule, i.e., the adsorp- tion enthalpy or heat of adsorption, as the hydrogen atoms are the main sites contributing to the adsorption. However, the constant gas–framework interactions suggest that internal interactions inside the framework involving the hydroxyl group and organic counter- part have significant contributions to the binding energy of these materials. SUPPLEMENTARY MATERIAL See the supplementary material for density of states obtained for the metal–organic frameworks under investigation using the tetrahedron method with Blöchl corrections and final configura- tion for gas adsorption inside MIL-53(Al3+) and MIL-53(Cu2+) after ionic relaxation. The supplementary material is available free of charge on the ACS Publications website. D. Structural analysis: The non-spin polarized case It has been discussed in Subsection III C that the inactivity of the metallic center to affect the gas–framework interactions should lead to more similar values for Eb. In order to address this ques- tion, the main gas–framework and framework–framework interac- tions are investigated in this subsection. Figures 5 and 6 highlight these interactions prior and posterior to the gas adsorption, respec- tively, where O1–O3 correspond to oxygen atoms from the organic counterpart. This analysis has been performed using the non-spin polarized case for the same interaction site [site (1) for Fe has the Other interactions inside the framework after adsorption are quite constant regardless of the metallic center. For instance, d(H1⋅⋅⋅O4) and d(H2⋅⋅⋅O5) distances lie in the range 1.97–2.05 Å for all systems, whereas the interaction between the oxygen atom from the organic counterpart and the carbon atom, i.e., d(C1⋅⋅⋅O6), is about 2.81–2.90 Å. Thus, these interactions are not dictating the differences seen in the gas adsorption energetics of these frameworks. FIG. 6. The main interactions after gas adsorption at site (1) inside the MIL-53 (Fe3+). Note that the interactions may vary according to each system. The red, gray, and white spheres correspond to oxygen, carbon, and hydrogen atoms, respectively, whereas the golden sphere is representative of Fe, Al, and Cu. Level of theory: PBE/non-spin polarized. FIG. 6. The main interactions after gas adsorption at site (1) inside the MIL-53 (Fe3+). Note that the interactions may vary according to each system. The red, gray, and white spheres correspond to oxygen, carbon, and hydrogen atoms, respectively, whereas the golden sphere is representative of Fe, Al, and Cu. Level of theory: PBE/non-spin polarized. r gas adsorption at site (1) inside the MIL-53 (Fe3+). Note that the interactions may vary according to each system. The red, gray, and white arbon, and hydrogen atoms, respectively, whereas the golden sphere is representative of Fe, Al, and Cu. Level of theory: PBE/non-spin J. Chem. Phys. 155, 024701 (2021); doi: 10.1063/5.0054874 J. Chem. Phys. 155, 024701 (2021); doi: 10.1063/5.0054874 © Author(s) 2021 155, 024701-8 © Author(s) 2021 The Journal of Chemical Physics The Journal of Chemical Physics ARTICLE scitation.org/journal/jcp TABLE II. Structural parameters given by atomic distances (d, in Å) and angle (a, in ○) of the main contributions to the gas adsorption energetics in MIL-53 (X), with X = Fe3+, Al3+, or Cu2+. REFERENCES 21B. C. R. Camacho, R. P. P. L. Ribeiro, I. A. A. C. Esteves, and J. P. B. Mota, “Adsorption equilibrium of carbon dioxide and nitrogen on the MIL-53(Al) metal organic framework,” Sep. Purif. Technol. 141, 150–159 (2015). 22 1World Meteorological Organization, “Greenhouse gas bulletin,” World Meteorol. Organ. Bull. 12, 1–4 (2017). 2J. Tollefson, “IPCC says limiting global warming to 1.5 ○C will require drastic action,” Nature 562(7726), 172–173 (2018). 22M. Mendt, B. Jee, D. Himsl, L. Moschkowitz, T. Ahnfeldt, N. Stock, M. Hartmann, and A. Pöppl, “A continuous-wave electron paramagnetic resonance study of carbon dioxide adsorption on the metal–organic framework MIL-53,” Appl. Magn. Reson. 45, 269–285 (2014). 3D. Y. C. Leung, G. Caramanna, and M. M. Maroto-Valer, “An overview of current status of carbon dioxide capture and storage technologies,” Renewable Sustainable Energy Rev. 39, 426–443 (2014). 23A. Boutin, F.-X. Coudert, M.-A. Springuel-Huet, A. V. Neimark, G. Férey, and A. H. Fuchs, “The behavior of flexible MIL-53(Al) upon CH4 and CO2 adsorption,” J. Phys. Chem. C 114(50), 22237–22244 (2010). 4H. Hellevang, “Carbon capture and storage (CCS),” in Petroleum Geoscience: From Sedimentary Environments to Rock Physics, 2nd ed. (Springer, 2015), pp. 591–602 24L. Hamon, C. Serre, T. Devic, T. Loiseau, F. Millange, G. Férey, and G. De Weireld, “Comparative study of hydrogen sulfide adsorption in the MIL-53(Al, Cr, Fe), MIL-47(V), MIL-100(Cr), and MIL-101(Cr) metal–organic frameworks at room temperature,” J. Am. Chem. Soc. 131(25), 8775–8777 (2009). 24L. Hamon, C. Serre, T. Devic, T. Loiseau, F. Millange, G. Férey, and G. De Weireld, “Comparative study of hydrogen sulfide adsorption in the MIL-53(Al, Cr, Fe), MIL-47(V), MIL-100(Cr), and MIL-101(Cr) metal–organic frameworks 5S. C. Page, A. G. Williamson, and I. G. Mason, “Carbon capture and stor- age: Fundamental thermodynamics and current technology,” Energy Policy 37(9), 3314–3324 (2009). Weireld, Comparative study of hydrogen sulfide adsorption in the MIL 53(Al, Cr, Fe), MIL-47(V), MIL-100(Cr), and MIL-101(Cr) metal–organic frameworks at room temperature,” J. Am. Chem. Soc. 131(25), 8775–8777 (2009). 25 6G. B. Damas, A. B. A. Dias, and L. T. Costa, “A quantum chemistry study for ionic liquids applied to gas capture and separation,” J. Phys. Chem. B 118(30), 9046–9064 (2014). 25P. Rallapalli, D. Patil, K. P. Prasanth, R. S. Somani, R. V. Jasra, and H. C. Bajaj, “An alternative activation method for the enhancement of methane storage capac- ity of nanoporous aluminium terephthalate, MIL-53(Al),” J. Porous Mater. 17, 523–528 (2010). 7M. R. M. Abu-Zahra, L. H. J. REFERENCES Schneiders, J. P. M. Niederer, P. H. M. Feron, and G. F. Versteeg, “CO2 capture from power plants: Part I. A parametric study of the technical performance based on monoethanolamine,” Int. J. Greenhouse Gas Control 1(1), 37–46 (2007). 26L. Vanduyfhuys and G. Maurin, “Thermodynamic modeling of the selective adsorption of carbon dioxide over methane in the mechanically constrained breathing MIL-53(Cr),” Adv. Theory Simul. 2, 1900124 (2019). 8Z. Liang, M. Marshall, and A. L. Chaffee, “CO2 adsorption-based separation by metal organic framework (Cu-BTC) versus zeolite (13X),” Energy Fuels 23(5), 2785–2789 (2009). 27A. Torrisi, R. G. Bell, and C. Mellot-Draznieks, “Functionalized MOFs for enhanced CO2 capture,” Cryst. Growth Des. 10(7), 2839–2841 (2010). 28i 28Z. Xiang, S. Leng, and D. Cao, “Functional group modification of metal–organic frameworks for CO2 capture,” J. Phys. Chem. C 116(19), 10573–10579 (2012). 9B. Dutcher, M. Fan, and A. G. Russell, “Amine-based CO2 capture technology development from the beginning of 2013—A review,” ACS Appl. Mater. Interfaces 7(4), 2137–2148 (2015). 29C. A. Trickett, A. Helal, B. A. Al-Maythalony, Z. H. Yamani, K. E. Cordova, and O. M. Yaghi, “The chemistry of metal–organic frameworks for CO2 capture, regeneration and conversion,” Nat. Rev. Mater. 2, 17045 (2017). 10F. Vega, M. Cano, S. Camino, L. M. G. Fernández, E. Portillo, and B. Navarrete, “Solvents for carbon dioxide capture,” in Carbon Dioxide Chemistry (Capture and Oil Recovery, 2018). 30A. Das, M. Choucair, P. D. Southon, J. A. Mason, M. Zhao, C. J. Kepert, A. T. Harris, and D. M. D’Alessandro, “Application of the piperazine-grafted CuBTTri metal-organic framework in postcombustion carbon dioxide capture,” Microporous Mesoporous Mater. 174, 74–80 (2013). 11C. H. Yu, C. H. Huang, and C. S. Tan, “A review of CO2 capture by absorption and adsorption,” Aerosol Air Qual. Res. 12, 745–769 (2012). 12 12L. Mathivathanan, J. Torres-King, J. N. Primera-Pedrozo, O. J. García-Ricard, A. J. Hernández-Maldonado, J. A. Santana, and R. G. Raptis, “Selective CO2 adsorption on metal-organic frameworks based on trinuclear Cu3-pyrazolato complexes: An experimental and computational study,” Cryst. Growth Des. 13(6), 2628–2635 (2013). 31D. K. Yoo, T.-U. Yoon, Y.-S. Bae, and S. H. Jhung, “Metal-organic framework MIL-101 loaded with polymethacrylamide with or without further reduction: Effective and selective CO2 adsorption with amino or amide functionality,” Chem. Eng. J. 380, 122496 (2020). 32Q. Yan, Y. Lin, P. Wu, L. Zhao, L. Cao, L. Peng, C. Kong, and L. ACKNOWLEDGMENTS This research project received financial support from the Swedish Research Council (VR) and STandUP for Energy collab- oration, with computational resources provided by the Swedish National Infrastructure for Computing (SNIC) at the PDC Cen- ter for High Performance Computing and National Supercom- puter Centre (NSC). G.B.D. acknowledges CAPES (Coordenação de Aperfeiçoamento de Pessoal de Ensino Superior) for financial In fact, the proper description of the metal orbital occupancy in the open shell systems is achieved using the spin-polarized GGA+U calculations. The atomic magnetic moment on the metallic center is, in this context, an important parameter to be tracked throughout the adsorption process, as it should remain constant prior and pos- terior to the adsorption. Here, MIL-53(Fe3+) is found to stabilize on the high-spin configuration with five unpaired electrons per atom J. Chem. Phys. 155, 024701 (2021); doi: 10.1063/5.0054874 © Author(s) 2021 155, 024701-9 The Journal of Chemical Physics The Journal of Chemical Physics ARTICLE scitation.org/journal/jcp frameworks materials MIL-53 (Al, Cr) and MIL-47 (V) by density functional theory,” J. Phys. Chem. C 112(2), 514–520 (2008). support of her Ph.D. studies. L.T.C. acknowledges support from CAPES/Print/UFF Grant No. 8881.310460/2018-01 and CAPES- frameworks materials MIL-53 (Al, Cr) and MIL-47 (V) by density functional theory,” J. Phys. Chem. C 112(2), 514–520 (2008). 18S. Bourrelly, P. L. Llewellyn, C. Serre, F. Millange, T. Loiseau, and G. Férey, “Different adsorption behaviors of methane and carbon dioxide in the iso- typic nanoporous metal terephthalates MIL-53 and MIL-47,” J. Am. Chem. Soc. 127(39), 13519–13521 (2005). STINT Grant No. 88887.465528/2019-00 and the CNPq Fellowship. The authors declare no conflicts of interest. DATA AVAILABILITY 19S. Andonova, E. Ivanova, J. Yang, and K. Hadjiivanov, “Adsorption forms of CO2 on MIL-53(Al) and MIL-53(Al)–OHx as revealed by FTIR spectroscopy,” J. Phys. Chem. C 121(34), 18665–18673 (2017). The data that support the findings of this study are available within the article. 20D. Angi and F. Cakicioglu-Ozkan, “Adsorption kinetics of methane reformer off-gases on aluminum based metal-organic framework,” Int. J. Hydrogen Energy 45, 34918 (2020). REFERENCES 155, 024701 (2021); doi: 10.1063/5.0054874 155, 024701-10 © Author(s) 2021 The Journal of Chemical Physics The Journal of Chemical Physics ARTICLE scitation.org/journal/jcp 45G. Kumari, N. R. Patil, V. S. Bhadram, R. Haldar, S. Bonakala, T. K. Maji, and C. Narayana, “Understanding guest and pressure-induced porosity through structural transition in flexible interpenetrated MOF by Raman spectroscopy,” J. Raman Spectrosc. 47, 149–155 (2016). 37R. L. Siegelman, P. J. Milner, A. C. Forse, J.-H. Lee, K. A. Colwell, J. B. Neaton,i J. A. Reimer, S. C. Weston, and J. R. Long, “Water enables efficient CO2 cap- ture from natural gas flue emissions in an oxidation-resistant diamine-appended metal–organic framework,” J. Am. Chem. Soc. 141(33), 13171–13186 (2019). 46S. Grimme, J. Antony, S. Ehrlich, and H. Krieg, “A consistent and accurate ab initio parametrization of density functional dispersion correc- tion (DFT-D) for the 94 elements H-Pu,” J. Chem. Phys. 132(15), 154104 (2010). 38J. Hafner and G. Kresse, “The vienna ab-initio simulation program VASP: An efficient and versatile tool for studying the structural, dynamic, and elec- tronic properties of materials,” in Properties of Complex Inorganic Solids (Springer, Boston, MA, 1997), pp. 69–82. 39F. Millange, N. Guillou, R. I. Walton, J.-M. Grenèche, I. Margiolaki, and G. Férey, “Effect of the nature of the metal on the breathing steps in MOFs with dynamic frameworks,” Chem. Commun. 2008(39), 4732–4734. 40 47C. Zhang, L. Ai, and J. Jiang, “Solvothermal synthesis of MIL-53(Fe) hybrid magnetic composites for photoelectrochemical water oxidation and organic pol- lutant photodegradation under visible light,” J. Mater. Chem. A 3(6), 3074–3081 (2015). 40S. Chibani, F. Chiter, L. Cantrel, and J.-F. Paul, “Capture of iodine species in MIL-53(Al), MIL-120(Al), and HKUST-1(Cu) periodic DFT and ab-initio molecular dynamics studies,” J. Phys. Chem. C 121(45), 25283–25291 (2017). 48J. P. Perdew, “Density functional theory and the band gap problem,” Int. J. Quantum Chem. 28(S19), 497–523 (1985). 41J. P. Perdew, K. Burke, and M. Ernzerhof, “Generalized gradient approximation made simple,” Phys. Rev. Lett. 77, 3865 (1996). 49G. B. Damas, C. R. Miranda, R. Sgarbi, J. M. Portela, M. R. Camilo, F. H. B. Lima, and C. M. Araujo, “On the mechanism of carbon dioxide reduction on Sn-based electrodes: Insights into the role of oxide surfaces,” Catalysts 9(8), 636 (2019). 42Z. Akimbekov, A. D. Katsenis, G. P. Nagabhushana, G. Ayoub, M. Arhangelskis, A. J. Morris, T. Friˇsˇci´c, and A. J. Chem. Phys. 155, 024701 (2021); doi: 10.1063/5.0054874 © Author(s) 2021 REFERENCES Chen, “Designed synthesis of functionalized two-dimensional metal–organic frameworks with pref- erential CO2 capture,” ChemPlusChem 78, 86–91 (2013). 13Y. Hu, W. M. Verdegaal, S. H. Yu, and H. L. Jiang, “Alkylamine-tethered stable metal–organic framework for CO2 capture from flue gas,” ChemSusChem 7(3), 734–737 (2014). 33J. Liu, J. Tian, P. K. Thallapally, and B. P. McGrail, “Selective CO2 capture from flue gas using metal–organic frameworks—A fixed bed study,” J. Phys. Chem. C 116(17), 9575–9581 (2012). 14P. L. Llewellyn, S. Bourrelly, C. Vagner, N. Heymans, H. Leclerc, A. Ghoufi, P. Bazin, A. Vimont, M. Daturi, T. Devic, C. Serre, G. De Weireld, and G. Maurin, “Evaluation of MIL-47(V) for CO2-related applications,” J. Phys. Chem. C 117(2), 962–970 (2013). 14P. L. Llewellyn, S. Bourrelly, C. Vagner, N. Heymans, H. Leclerc, A. Ghoufi, P. Bazin, A. Vimont, M. Daturi, T. Devic, C. Serre, G. De Weireld, and G. Maurin, “Evaluation of MIL-47(V) for CO2-related applications,” J. Phys. Chem. C 117(2), 962–970 (2013). 34H. Huang, W. Zhang, D. Liu, and C. Zhong, “Understanding the effect of trace amount of water on CO2 capture in natural gas upgrading in metal–organic frame- works: A molecular simulation study,” Ind. Eng. Chem. Res. 51(30), 10031–10038 (2012). 15J. Khan, N. Iqbal, A. Asghar, and T. Noor, “Novel amine functionalized metal organic framework synthesis for enhanced carbon dioxide capture,” Mater. Res. Express 6(10), 105539 (2019). 35Y. F. Chen, R. Babarao, S. I. Sandler, and J. W. Jiang, “Metal–organic frame- work MIL-101 for adsorption and effect of terminal water molecules: From quantum mechanics to molecular simulation,” Langmuir 26(11), 8743–8750 (2010). 16N. Mosca, R. Vismara, J. A. Fernandes, G. Tuci, C. Di Nicola, K. V. Doma- sevitch, C. Giacobbe, G. Giambastiani, C. Pettinari, M. Aragones-Anglada, P. Z. Moghadam, D. Fairen-Jimenez, A. Rossin, and S. Galli, “Nitro-functionalized bis(pyrazolate) metal–organic frameworks as carbon dioxide capture materials under ambient conditions,” Chem. - Eur. J. 24(50), 13170–13180 (2018). 36R. Babarao, S. Dai, and D.-E. Jiang, “Functionalizing porous aromatic frame- works with polar organic groups for high-capacity and selective CO2 separation: A molecular simulation study,” Langmuir 27(7), 3451–3460 (2011). 17N. A. Ramsahye, G. Maurin, S. Bourrelly, P. L. Llewellyn, C. Serre, T. Loiseau, T. Devic, and G. Férey, “Probing the adsorption sites for CO2 in metal organic J. Chem. Phys. 155, 024701 (2021); doi: 10.1063/5.0054874 © Author(s) 2021 J. Chem. Phys. REFERENCES Navrotsky, “Experimental and theoretical evalu- ation of the stability of true MOF polymorphs explains their mechanochemical interconversions,” J. Am. Chem. Soc. 139(23), 7952–7957 (2017). 50I. N. Yakovkin and P. A. Dowben, “The problem of the band gap in LDA calculations,” Surf. Rev. Lett. 14(3), 481–487 (2007). 43W. You, Y. Liu, J. D. Howe, D. Tang, and D. S. Sholl, “Tuning binding ten- dencies of small molecules in metal–organic frameworks with open metal sites by metal substitution and linker functionalization,” J. Phys. Chem. C 122(48), 27486–27494 (2018). 51D. Guo, R. Wen, M. Liu, H. Guo, J. Chen, and W. Weng, “Facile fabrication of G-C3N4/MIL-53(Al) composite with enhanced photocatalytic activities under visible-light irradiation,” Appl. Organomet. Chem. 29(10), 690–697 (2015). 52H. R. Mahdipoor, R. Halladj, E. Ganji Babakhani, S. Amjad-Iranagh, and J. Sadeghzadeh Ahari, “Synthesis, characterization, and CO2 adsorption properties of metal organic framework Fe-BDC,” RSC Adv. 11, 5192–5203 (2021). 44G. W. Mann, K. Lee, M. Cococcioni, B. Smit, and J. B. Neaton, “First-principles Hubbard U approach for small molecule binding in metal-organic frameworks,” J. Chem. Phys. 144, 174104 (2016). J. Chem. Phys. 155, 024701 (2021); doi: 10.1063/5.0054874 © Author(s) 2021 155, 024701-11 155, 024701-11
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Transcriptomic analysis between self- and cross-pollinated pistils of tea plants (Camellia sinensis)
BMC genomics
2,018
cc-by
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Ma et al. BMC Genomics (2018) 19:289 https://doi.org/10.1186/s12864-018-4674-1 Ma et al. BMC Genomics (2018) 19:289 https://doi.org/10.1186/s12864-018-4674-1 Open Access © The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Transcriptomic analysis between self- and cross-pollinated pistils of tea plants (Camellia sinensis) Qingping Ma1, Changsong Chen2, Zhongping Zeng1, Zhongwei Zou3, Huan Li1, Qiongqiong Zhou1, Xuan Chen1, Kang Sun1 and Xinghui Li1* Abstract Background: Self-incompatibility (SI) is a major barrier that obstructs the breeding process in most horticultural plants including tea plants (Camellia sinensis). The aim of this study was to elucidate the molecular mechanism of SI in tea plants through a high throughput transcriptome analysis. Results: In this study, the transcriptomes of self- and cross-pollinated pistils of two tea cultivars ‘Fudingdabai’ and ‘Yulv’ were compared to elucidate the SI mechanism of tea plants. In addition, the ion components and pollen tube growth in self- and cross-pollinated pistils were investigated. Our results revealed that both cultivars had similar pollen activities and cross-pollination could promote the pollen tube growth. In tea pistils, the highest ion content was potassium (K+), followed by calcium (Ca2+), magnesium (Mg2+) and phosphorus (P5+). Ca2+ content increased after self-pollination but decreased after cross-pollination, while K+ showed reverse trend with Ca2+. A total of 990 and 3 common differentially expressed genes (DEGs) were identified in un-pollinated vs. pollinated pistils and self- vs. cross-pollinated groups after 48 h, respectively. Function annotation indicated that three genes encoding UDP-glycosyltransferase 74B1 (UGT74B1), Mitochondrial calcium uniporter protein 2 (MCU2) and G-type lectin S-receptor-like serine/threonine-protein kinase (G-type RLK) might play important roles during SI process in tea plants. Conclusion: Ca2+ and K+ are important signal for SI in tea plants, and three genes including UGT74B1, MCU2 and G-type RLK play essential roles during SI signal transduction. Keywords: Self-incompatibility, Ion components, Pollen tube growth, Transcriptome GSI has been found in many plant species, such as Solanaceae [3, 4] and Rosaceae [5–7], while SSI is typically found in Brassicaceae [8]. Both GSI and SSI have male or female determinate conditions which are regulated by different prominent genes [9]. In GSI system, S locus- encoded F-box (SLF/SFB) proteins control the pollen recognition of S-RNase based SI [10–12]. In SSI systems, S-locus receptor kinase (SRK) gene and S-locus cysteine- rich protein (SCR)/S-locus protein-11 (SP11) function as a receptor-ligand pair to recognize self-pollens at the surface of stigma epidermal papilla cells [13]. The SRK is a membrane-spanning receptor protein in stigma containing an extracellular domain (S-domain) for recogni- tion of SP11, a transmembrane domain, and an intracellular serine/threonine kinase domain [14]. S-locus glycoprotein gene (SLG) and SRK exhibit series characteristics which are Background lf b Self-incompatibility (SI) is a common phenomenon in plant reproduction system, which prevents self-fertilization in flowering plants. There are two classical known mecha- nisms for SI, namely, homomorphic gametophytic self- incompatibility (GSI) and homomorphic sporophytic self-incompatibility (SSI). In GSI system, the pollen incompatibility (haploid male gametophyte) is controlled by the S allele, pollen and pistils bearing the same S allele trigger an incompatible reaction [1]. While in SSI system, incompatibility is determined by both S alleles of the (diploid-sporophyte) pollen parents [2]. * Correspondence: lxh@njau.edu.cn 1Tea Research Institute, Nanjing Agricultural University, Nanjing 210095, China Full list of author information is available at the end of the article Pollen culture in vitro Pollen culture medium was prepared with the following substances: 0.59 g MES, 0.02 g H3BO3, 0.05 g Ca(NO3) ·4H2O, 5 g sucrose and 5 g polyethylene glycol 4000 (PEG 4000), diluted with distilled water to 100 mL. Pollens were cultured in the medium in the dark and observed by Olympus light microscope (Olympus, Tokyo, Japan). Pollen germination rate and mean pollen tube length at 1, 2, and 4 h were calculated based on eight visual fields. Page 2 of 12 Ma et al. BMC Genomics (2018) 19:289 associated with the female determinant of SSI in Brassica [15]. The S domain of SRK is highly similar to the SLG, which is the first S-locus gene to be identified and a soluble glycoprotein secreted to the stigma surface [16, 17]. Besides, the pollen coat protein SCR/ SP11 controls pollen deter- minant of SSI in Brassica [8, 18], and many SP11, SRK, and SLG alleles were inherited together to term different S haplotypes. Fig. 1 Morphology of flowers from ‘Fudingdabai’ and ‘Yulv’ cultivars Self-incompatibility mechanism remains unclear in tea plant. Previous studies suggested that tea plant SI might be in late-acting self-incompatibility system (LSI), in that self-pollinated pollen tubes elongated through the style but failed in fertilization [19, 20]. This has made it almost impossible to obtain fruits in self-pollinated tea plants (Camellia sinensis); thus, breeding process in tea plant is not encouraged. LSI is a novel SI system in plants, but the molecular mechanism of this system is still unclear. Recently, Zhang et al. [21] found that tea plant SI might be categorized to GSI through transcrip- tome analysis. Therefore, the SI mechanism in tea plants is still controversial and needs further exploration. Fig. 1 Morphology of flowers from ‘Fudingdabai’ and ‘Yulv’ cultivars 8, 24, 48 and 72 h were picked from each combination and frozen quickly in liquid nitrogen and stored at −80 °C for RNA extraction. Three biological replicates were conducted with at least five pistils for each replicate. To understand the mechanism of SI in tea plant, the ion components and pollen tube growth in self- and cross-pollinated pistils were investigated. Furthermore, the transcriptome of self- and cross-pollinated pistils of two tea cultivars ‘Fudingdabai’ and ‘Yulv’ was compared to figure out the DEGs which may be involved in SI of tea plant. ‘Fudingdabai’ is a national superior clone and cultivated widely in China because of its good quality, high yield, and excellent stress resistance, while ‘Yulv’ is a high-quality cultivar selected from the hybrid offsprings of ‘Yabukita’. Both cultivars are self-incompatible and show high fruiting rates after cross-pollination. This study will provide reference for understanding SI mechanism of tea plant. Methods Fig. 2 The flow diagram of the experiment design. Red and green indicate pollination combination of the two tea cultivars in this study. The color dots mean pollens from the corresponding cultivars Identification of differentially expressed genes Identification of differentially expressed genes Fragments per Kilobase of transcript per Million mapped reads (FPKM) estimates produced by RNA-Seq by Cuffquant and Cuffnorm of Cufflinks was used to evaluate the expression of transcripts [29]. The transcriptome com- parisons of un-pollinated vs. pollinated groups and self- pollinated vs. cross-pollinated groups were conducted to find the differentially expressed genes (DEGs). Differential expression analyses were performed using the DESeq R package 1.10.1 [30], which provides statistical routines to determine DEGs based on a negative binomial distribution model. The P values were adjusted by the Benjamini and Hochberg’s approach for controlling the false discovery rate [31]. False discovery rate < 0.01 and fold change > 2 was considered to be significantly differentially expressed. Pearson’s Correlation Coefficient was used to evaluate the correlation of biological repeats [30]. Genome alignment and gene annotation Raw data of fastq format were processed, and then were cleaned by trimming the adapter sequences, ploy-A con- taining reads and low quality reads. The clean reads were aligned to the reference genome (http://www.plantking- domgdb.com/tea_tree/) by TopHat2 using the default parameters [22]. The mapped reads were assembled into possible transcripts by Cufflinks [23]. The unannotated transcripts were annotated by BLAST [24] based on the Statistical analysis The statistical analysis was conducted using Excel 2016 and GraphPad Prism 5.0 (San Diego, USA). The signifi- cance analysis of difference between two samples was evaluated with Student t-test and multiple comparisons were analyzed using One-way ANOVA and P < 0.05 was considered to be statistically significant. The results were displayed as mean ± standard deviation. Plant materials and treatments Two ten-year-old tea cultivars, namely, C. sinensis cv. Fudingdabai and C. sinensis cv. Yulv, cultivated in tea germplasm repository of Tea Research Institute of Fujian Academy of Agricultural Sciences were used in this study. Flowers from both of the two tea cultivars have three petals and trifid stigmas. The stigmas of ‘Fudingdabai’ divided at the base but ‘Yulv’ at the upper part (Fig. 1). Flower buds of the two tea cultivars were harvested at 4:00 pm for pollens collection. Besides, the remaining flower buds of two cultivars were emasculated and used for artificial pollination next morning. A total of four pollination combinations were conducted: ‘Fudingdabai’ (♂) × ‘Fudingdabai’ (♀),‘Yulv’ (♂) × ‘Yulv’ (♀),‘Fudingdabai’ (♂) × ‘Yulv’ (♀), and Yulv’ (♂) × ‘Fudingdabai’ (♀), as shown in Fig. 2. The un-pollinated and pollinated pistils at Fig. 2 The flow diagram of the experiment design. Red and green indicate pollination combination of the two tea cultivars in this study. The color dots mean pollens from the corresponding cultivars Ma et al. BMC Genomics (2018) 19:289 Page 3 of 12 Quantitative real time PCR verification Quantitative real time PCR verification The first-strand cDNA was synthesized from 1 μg of total RNA by using the RevertAid™First Strand cDNA Synthesis Kit (Thermo Scientific, MA, USA) according to the manual. Quantitative real time PCR (QRT-PCR) was performed using SYBR Premix EX Taq (Takara, Japan) on Roche LightCycler® 480II (Switzerland) as instruction specified. The qRT-PCR primers (Table 1) were designed by using Primer Premier 5.0 (Premier Biosoft International, Palo Alto, CA). The GAPDH (GenBank: GE651107) from tea plant was used as the reference gene. All of the PCR reac- tions were conducted in triplicate and the average expres- sion values were calculated. The relative expression level of each gene was calculated with the 2-ΔΔCT method [32]. RNA extraction, library construction and sequencing Total RNA was extracted using Plant RNA extraction kit (Bioteke, China) according to the manual. RNA quality and concentration were assessed by 1% agarose gels, Qubit®2.0 Fluorometer (Invitrogen, Carlsbad, USA), and Agilent Bioanalyzer 2100 system (Agilent, Palo Alto, USA). A total of 3 μg RNA per sample was used for sequencing libraries preparation by NEBNext®Ultra™ RNA Library Prep Kit for Illumina® (NEB, USA) following manufacturer’s instructions and library quality was assessed on the Agilent Bioanalyzer 2100 system (Agilent Technologies, Palo Alto, CA). The clustering of samples was performed using TruSeq PE Cluster Kit v3-cBot-HS (Illumina) according to the manufacturer’s instructions. Finally, sequencing analysis was carried out with an Illumina Hiseq 2500 platform to generate pair-end reads. Ion components of pistils Un-pollinated and pollinated styles were dried at 80 °C for 4 h. A total of 0.1 g dried samples (at least 15 pistils) were ground and digested in 5 ml nitric acid by ETHOS One high performance microwave digestion system (Milestone, Bergamo, Italy) for 1 h. The digested samples were diluted with nitric acid to 25 mL and analyzed by inductively coupled plasma-optical emission spectrometer (PerkinElmer Optima 2100DV, Massachusetts, USA). A total of nine ions were detected, including potassium (K+), calcium (Ca2+), magnesium (Mg2+), phosphorus (P5+), zinc (Zn2+), boron (B3+), Ferrous (Fe2+), aluminium (Al3+), and manganese (Mn2+). The contents of the ions were quantified by establishing standard curve. Fluorescence activity of pollen tube following databases: NR (NCBI non-redundant protein sequences) [25], COG (Clusters of Orthologous Groups of proteins) [26], Swiss-Prot (A manually annotated and reviewed protein sequence database) [27], KEGG (Kyoto Encyclopedia of Genes and Genomes) and GO (Gene Ontology) [28]. following databases: NR (NCBI non-redundant protein sequences) [25], COG (Clusters of Orthologous Groups of proteins) [26], Swiss-Prot (A manually annotated and reviewed protein sequence database) [27], KEGG (Kyoto Encyclopedia of Genes and Genomes) and GO (Gene Ontology) [28]. Fresh un-pollinated and pollinated styles were fixed in FAA fixative buffer (5 mL formalin, 6 mL acetic acid, and 89 mL 50% ethanol) for 24 h [19]. The styles were washed with deionized water and then softened by 2 M NaOH overnight. The softened styles were stained by 0.1% aniline blue solution dissolved with 0.15 M K2HPO4. Finally, the styles were observed under Leica DM6B fluorescence microscope (Leica, Bannockburn, USA) after 15 min staining. At least five styles were observed for each sample. Results Pollen germination in vitro and fluorescence of pollen tubes In order to evaluate the pollen vitality, pollen germination rate and tube growth between ‘Fudingdabai’ and ‘Yulv’ were assessed and compared. As shown in Additional Ma et al. BMC Genomics (2018) 19:289 Page 4 of 12 Table 1 The primers used for qRT-PCR verification ID Forward (5′-3′) Reverse (5′-3′) CSA006398 GGCGTATCCAACAATCTTATCG CCAAACCCAATCATCATCCA CSA005891 GAACGTGTGTTGGTCATTGAT CATAAATTGTCTACTGGCGAG CSA028406 GAGATTCAGTTGTCGCTTTG AGAGCCACCATTTCATTAGC CSA024717 CCACTGCCACTTGTCGTTGTT GAGTTTGCCACCGTGAATTCG CSA002728 GTCGTTCCACTGGCTTCCTAC GGCAGTAGTTGTTCATAGAGA CSA026098 GGCTCCCTCTTTCTTTATATG CCACCATCAATTTCTCCCTTG CSA024379 TCCCATCATTAGCCTGCCAAC ATCCCATCTCAGCCCATAAC GAPDH TTGGCATCGTTGAGGGTCT CAGTGGGAACACGGAAAGC pistils, respectively. Taken these results together, pollens from other cultivars would grow faster in pistils than that from themselves. This result was similar to that by Zhang et al. [21]. In addition, reciprocal cross-pollination showed that the pollen tube growth was slower when ‘Fudingdabai’ was used as maternal parent. However, pollen tubes in all of the self- and cross-pollinated samples reached the base of styles after 48 h. Ion components in self- and cross-fertilized pistils Ion components, especially Ca2+, are an indicator of self-incompatibility [33]. In tea pistils, the highest level of ion component observed in the tea pistil was K+, followed by Ca2+, Mg2+ and P5+ in sequence (Fig. 3a). Pistils of ‘Fudingdabai’ contained more K+ but less Ca2+ than those in ‘Yulv’. Ca2+ content in self-pollinated pistils of ‘Yulv’ (YLS) was higher than that in cross-pollinated pistils of ‘Yulv’ (YLC), but no apparent difference between self- (FDS) and cross-pollinated pistils of ‘Fudingdabai’ (FDC). In FDS pistils, the K+ content was higher than in FDC pistils, suggesting that Ca2+ and K+ may be involved in potential signal transduction in SI. file 1: Figure S1A, the pollen appearance between two cultivars has no significant difference. Pollen germination rate and mean length of pollen tubes of the two cultivars were similar and increased gradually with prolongation of the growth time (Additional file 1: Figure S1B). The fluorescence of pollen tube was observed to exam- ine the growth of pollens in pistils (Additional file 2: Figure S2). After 8 h self-fertilization of ‘Fudingdabai’, the pollens germinated at stigma but no fluorescence was seen in styles. After 24 h, a few pollen tubes entered styles and the fluorescence on the base of styles was observed firstly after 48 h. Pollen tubes of ‘Yulv’ (♂) × ‘Fudingdabai’ (♀) cross-fertilized pistils showed higher growth rate than ‘Fudingdabai’ self-fertilization. Results The pollen tubes arrived at the base of styles after 24 and 8 h in self-fertilized ‘Yulv’ pistils and ‘Fudingdabai’ (♂) × ‘Yulv’ (♀) cross-fertilized Differentially expressed genes between self- and cross-pollinated groups Correlation analysis showed that T02 of self-pollinated ‘Fudingdabai’ at 48 h (FDS48) revealed low correlation to other two FDS48 samples (T07 and T12) with R2 of 0. 33 and 0.43, respectively. T15 of self-pollinated ‘Yulv’ pistil sample at 48 h (YLS48) deviated from other two replicates (T05 and T10) with R2 of 0.46 and 0.52, respectively. These two samples (T02 and T15) were therefore removed in further DEG analysis. All replicates of remaining samples showed high correlation (Fig. 4). In comparison of self- and cross-pollinated groups, only three common DEGs were found (Fig. 6a). The 1160 common DEGs identified at least in two comparisons were therefore considered in further analysis. COG func- tion classification revealed that ‘General function predic- tion only’ contained the most common DEGs followed by ‘Replication, recombination and repair’, ‘Transcription’ and ‘Signal transduction’. This result shows that cross- fertilization caused a series of responses in transcriptional level. In addition, the three common DEGs in all compari- sons were UDP-glycosyltransferase 74B1 (UGT74B1, CSA001819), Mitochondrial calcium uniporter protein 2 (MCU2, CSA014152) and G-type lectin S-receptor- like serine/threonine-protein kinase RLK1 (G-lecRLK, Camellia_sinensis_newGene_13508). These genes showed similar expression patterns in un-pollinated and pollinated pistils. They also expressed at same levels during reciprocal cross-pollinations, but adversely expressed during self- A total of 1948, 3399, 3927, 3682, 145, 2061, 1343, 600 and 1859 genes were found to be differentially expressed between each of un-pollinated ‘Fudingdabai’ pistils (FD0) vs. FDS48, FD0 vs. cross-pollinated ‘Fudingdabai’ (♀) pistils after 48 h (FDC48), un-pollinated ‘Yulv’ pistils (YL0) vs. YLS48, YL0 vs. cross-pollinated ‘Yulv’ (♀) pistils after 48 h (YLC48), FDS48 vs. FDC48, FDS48 vs. YLC48, YLS48 vs. FDC48, YLS48 vs. YLC48 and FDC48 vs. YLC48, respect- ively (Fig. 5a). By comparing the pollinated groups with un-pollinated groups, 990 common DEGs were found (Fig. 5b). Transcriptome assembly and function annotation A total of 18 samples were sequenced and 122.75 Gb clean data were obtained. The percentages of clean reads having a base quality greater or equal than Q30 were above 85.01% indicating that the data produced by sequencing are of high quality. The clean reads from the Fig. 3 Ion components in self- and cross-pollinated pistils of tea plants. a 1 un-pollinated ‘Fudingdabai’ pistils; 2–5 self-pollinated ‘Fudingdabai’ pistils at 8 h, 24 h, 48 h and 72 h; 6–9 ‘Yulv’(♂) × ‘Fudingdabai’(♀) at 8 h, 24 h, 48 h and 72 h; 10 un-pollinated ‘Yulv’ pistils; 11–14 self-pollinated ‘Yulv’ pistils at 8 h, 24 h, 48 h and 72 h; 15–18 ‘Yulv’(♀) × ‘Fudingdabai’(♂) at 8 h, 24 h, 48 h and 72 h. b The Ca2+ and K+ content during self- and cross-pollinated pistils Fig. 3 Ion components in self- and cross-pollinated pistils of tea pla pistils at 8 h, 24 h, 48 h and 72 h; 6–9 ‘Yulv’(♂) × ‘Fudingdabai’(♀) a Fig. 3 Ion components in self- and cross-pollinated pistils of tea plants. a 1 un-pollinated ‘Fudingdabai’ pistils; 2–5 self-pollinated ‘Fudingdabai’ pistils at 8 h, 24 h, 48 h and 72 h; 6–9 ‘Yulv’(♂) × ‘Fudingdabai’(♀) at 8 h, 24 h, 48 h and 72 h; 10 un-pollinated ‘Yulv’ pistils; 11–14 self-pollinated ‘Yulv’ pistils at 8 h, 24 h, 48 h and 72 h; 15–18 ‘Yulv’(♀) × ‘Fudingdabai’(♂) at 8 h, 24 h, 48 h and 72 h. b The Ca2+ and K+ content during self- and cross-pollinated pistils Page 5 of 12 Ma et al. BMC Genomics (2018) 19:289 Page 5 of 12 ‘General function prediction only’ enriched most of DEGs, followed by ‘Transcription’,‘Signal transduction mechanisms’, ‘Replication, recombination and repair’ and ‘Secondary metabolites biosynthesis, transport and catabolism’ (Fig. 5c). GO enrichment analysis revealed that metabolic process in biological process, cell part in cellular component and cata- lytic activity in molecular function enriched the most DEGs (Additional file 3: Figure S3). 18 samples showed alignment ratios between 47.77% and 54.96% (SRA accession: SRP110788, Table 2). Based on the alignment with the reference genome of tea, 8136 unannotated genes were found, and 6621 of these genes were annotated after BLAST, with 1481 unigenes in COG database, 3465 in GO database, 2301 in KEGG database, 4285 in Swissprot database and 6588 in Nr database. Differentially expressed genes between self- and cross-pollinated groups COG classification of these DEGs showed that Table 2 The alignment of transcriptomic reads on genome Sample Total Reads Mapped Reads (%) Unique Mapped Reads Multiple Map Reads FD0–1 41,191,716 21,483,151 (52.15%) 49.14% 3.01% FD0–2 47,556,326 22,717,253 (47.77%) 43.74% 4.03% FD0–3 42,082,490 22,243,075 (52.86%) 49.41% 3.44% FDS48–1 42,900,034 22,929,028 (53.45%) 49.59% 3.86% FDS48–2 47,034,306 23,852,770 (50.71%) 46.94% 3.77% FDS48–3 45,609,388 23,605,185 (51.76%) 48.43% 3.33% FDC48–1 48,440,032 25,869,526 (53.41%) 50.72% 2.68% FDC48–2 41,896,840 21,354,194 (50.97%) 47.74% 3.23% FDC48–3 49,373,892 25,641,271 (51.93%) 49.57% 2.37% YL0–1 46,464,662 23,481,565 (50.54%) 47.86% 2.68% YL0–2 43,549,168 23,651,982 (54.31%) 52.27% 2.04% YL0–3 41,549,084 21,639,699 (52.08%) 49.26% 2.82% YLS48–1 53,246,958 26,180,870 (49.17%) 46.35% 2.82% YLS48–2 50,605,784 27,367,119 (54.08%) 51.17% 2.91% YLS48–3 40,743,908 21,133,266 (51.87%) 45.29% 6.57% YLC48–1 45,900,260 25,068,461 (54.62%) 51.87% 2.74% YLC48–2 53,049,730 29,157,364 (54.96%) 52.29% 2.67% YLC48–3 47,106,846 24,086,169 (51.13%) 48.49% 2.64% Ma et al. BMC Genomics (2018) 19:289 Page 6 of 12 Fig. 4 Correlation analysis of the samples for differential expression analysis. Different sample numbers represent un-pollinated ‘Fudingdabai’ pistils (FD0), self-pollinated ‘Fudingdabai’ pistils at 48 h (FDS48), ‘Yulv’(♂) × ‘Fudingdabai’(♀) at 48 h (FDC48), un-pollinated ‘Yulv’ pistils (YL0), self-pollinated ‘Yulv’ pistils at 48 h (YLS48) and ‘Yulv’(♀) × ‘Fudingdabai’(♂) at 48 h (YLC48), respectively. Bold values are R2 for replicates of each sample Fig. 4 Correlation analysis of the samples for differential expression analysis. Different sample numbers represent un-pollinated ‘Fudingdabai’ pistils (FD0), self-pollinated ‘Fudingdabai’ pistils at 48 h (FDS48), ‘Yulv’(♂) × ‘Fudingdabai’(♀) at 48 h (FDC48), un-pollinated ‘Yulv’ pistils (YL0), self-pollinated ‘Yulv’ pistils at 48 h (YLS48) and ‘Yulv’(♀) × ‘Fudingdabai’(♂) at 48 h (YLC48), respectively. Bold values are R2 for replicates of each sample Fig. 4 Correlation analysis of the samples for differential expression analysis. Different sample numbers represent un-pollinated ‘Fudingdabai’ pistils (FD0), self-pollinated ‘Fudingdabai’ pistils at 48 h (FDS48), ‘Yulv’(♂) × ‘Fudingdabai’(♀) at 48 h (FDC48), un-pollinated ‘Yulv’ pistils (YL0), self-pollinated ‘Yulv’ pistils at 48 h (YLS48) and ‘Yulv’(♀) × ‘Fudingdabai’(♂) at 48 h (YLC48), respectively. Bold values are R2 for replicates of each sample pollinations of the two cultivars (Fig. 6b). Function annotation found that G-lecRLK was functioned on ‘Signal transduction mechanisms’. MCU2 worked on ‘Energy pro- duction and conversion’ and ‘Carbohydrate transport and metabolism’. Finally, UGT74B1 was annotated to ‘General function prediction only’. Except for ‘general function prediction only’, the classes of ‘Replication, recombination and repair’, ‘Transcription’ and ‘Signal transduction’ enriched most of the DEGs. Differentially expressed genes between self- and cross-pollinated groups In addition, G-lecRLK, MCU2 and UGT74B1 were found in these common DEGs, suggesting that these DEGs played vital roles during SI process. In the five overlapping genes, MCU2 and UGT74B1 were found. G-lecRLK was only expressed in the comparisons in our study because it was annotated by database blast but not genome mapping. In order to compare our results to the previous study [21], the data from self-pollinated (FDS48–1, SRR3290055) and cross-pollinated ‘Fudingdabai’ samples (FDC48–1, SRR3290084) at 48 h were downloaded and re-analyzed based on genome of tea plants. A total of 4262 DEGs were identified between FDS48–1 and FDC48–1 comparison. According to the large number of DEGs, we suggested that ‘Fudingdabai’ should be used as the paternal parent in the study of Zhang et al. [21]. As shown in Fig. 7, in compari- son of self- and cross-pollinated groups (FDS48 vs. FDC48, FDS48 vs. YLC48 and FDS48–1 vs. FDC48–1), only five common DEGs were filtered. Therefore, the common DEGs identified at least in two comparisons were con- cerned. COG function classification revealed similar result to the four groups comparisons in our study (Fig. 7). Verification of differentially expressed genes and resulting in self-recognition. Interactions between pollen and pistil in the same haplotype triggered a SI response, which inhibits pollen tube growth and leads to failure of fertilization [34]. During SI process, a series of signal changes occurred in plants. The earliest identified physiological event caused by SI recognition is the increase of Ca2+ in incompatible pollen tubes or stigma papilla cells [35, 36]. In the present study, Ca2+ changes suggest a potential correlation between pollen tube growth and Ca2+ content. Furthermore, the opposing trend of Ca2+ ion content of the two cultivars between self- and cross-pollinated pistils reveals that Ca2+ may be an important signal for SI in tea plants. DEGs between reciprocal cross-pollinations In the present study, 1859 DEGs were identified in FDC48 vs. YLC48 comparison. Except for ‘General function predic- tion only’, most of these DEGs were involved in ‘Transcrip- tion’ and ‘Replication, recombination and repair’ (Fig. 8a). KEGG pathway enrichment analysis showed that ‘Galactose metabolism’ possessed the highest rich factor and ‘Phe- nylpropanoid biosynthesis’ had the most DEGs (Fig. 8b). This result suggests different responses between reciprocal cross-pollinations in tea cultivars. Ma et al. BMC Genomics (2018) 19:289 Page 7 of 12 Fig. 5 Differentially expressed genes identified in different comparisons. a The number of DEGs found in different comparisons. b, c Venn diagram and COG annotation for DEGs between un-pollinated and pollinated groups Fig. 5 Differentially expressed genes identified in different comparisons. a The number of DEGs found in different comparisons. b, c Venn diagram and COG annotation for DEGs between un-pollinated and pollinated groups Fig. 5 Differentially expressed genes identified in different comparisons. a The number of DEGs found in different comparisons. b, c Venn diagram and COG annotation for DEGs between un-pollinated and pollinated groups Verification of differentially expressed genes In order to verify the reliability of RNA-Seq data, eight DEGs were selected for qRT-PCR analysis. As shown in Fig. 9, most of the DEGs showed similar expression trend compared to the RNA-Seq analysis. Therefore, the RNA-Seq analysis is credible. Discussion Self-incompatibility is a common phenomenon in angio- sperm. In order to understand the SI mechanism of tea plants, we studied the ion components and pollen growth in self- and cross-pollinated pistils from two tea cultivars. The results showed that pollen tubes grew faster in cross-pollinated pistils than those in self-pollinated pistils. Furthermore, Ca2+ in pistils increased after self-pollinations but decreased after cross-pollinations. In addition, compara- tive transcriptome analysis showed that G-type LecRLK, UGT74B1 and MCU2 genes might contribute the SI signal transduction mechanism in tea plant. In the present study, a DEG MCU2 was identified between self- and cross-pollination, which undertook the mitochondrial Ca2+ uptake [37]. In animals, Ca2+ uptake could regulate the mitochondrial energy production that is a stimulation of sperm-induced Ca2+ release [38]. There is evidence that the Ca2+ uptake also occurred at fertilization in mammalian eggs [39]. Inhibition of the mitochondrial function also disrupted the sperm-induced Ca2+ oscillatory pattern and intracellular Ca2+ homeostasis, and resulted in low developmental competence in mammals Signal transduction during self-incompatibility in tea plants Self-incompatibility is genetically regulated by a multi- allelic S-locus which links pollen and pistil S-determinants Ma et al. BMC Genomics (2018) 19:289 Page 8 of 12 Fig. 6 DEGs identified between self- and cross-pollinated groups. a Venn diagram for DEGs between self- and cross-pollinated groups. b The ex- pression of the three common DEGs between self- and cross-pollinated groups Fig. 6 DEGs identified between self- and cross-pollinated groups. a Venn diagram for DEGs between self- and cross-pollinated groups. b The ex- pression of the three common DEGs between self- and cross-pollinated groups Ca2+ after pollination (Fig. 3). We can therefore propose that SI activates a nonspecific ion channel in tea plants. [40]. Unlike in animals, the functional mechanism of MCU in tea plants has been less studies, and; therefore, needs verification except for Ca2+, K+ is also sensitive to SI. In Papaver rhoeas, conductance of some monovalent cations, such as K+ and NH4 + were also stimulated by SI [41]. Interestingly, content of K+ changes was opposite to Role of self-incompatibility related genes in tea plants LecRLK family has been classified to three subfamilies: L-type, G-type and C-type LecRLKs. This classification Fig. 7 Venn diagram and COG function classification for DEGs identified between self- and cross-pollinated groups. FDS48–1 and FDC48–1 are self- and cross pollinated samples from the study by Zhang et al. Fig. Discussion 7 Venn diagram and COG function classification for DEGs identified between self- and cross-pollinated groups. FDS48–1 and FDC48–1 are self- and cross pollinated samples from the study by Zhang et al. Ma et al. BMC Genomics (2018) 19:289 Page 9 of 12 Fig. 8 The DEGs between reciprocal cross-pollinations. a COG function classification of DEGs between reciprocal cross-pollinations. b KEGG enrichment analysis of DEGs between reciprocal cross-pollinations Fig. 8 The DEGs between reciprocal cross-pollinations. a COG function classification of DEGs between reciprocal cross-pollinations. b KEGG enrichment analysis of DEGs between reciprocal cross-pollinations Fig. 8 The DEGs between reciprocal cross-pollinations. a COG function classification of DEGs between reciprocal cross-pollinations. b KEGG enrichment analysis of DEGs between reciprocal cross-pollinations Fig. 8 The DEGs between reciprocal cross-pollinations. a COG function classification of DEGs between reciprocal cross-pollinations. b KEGG enrichment analysis of DEGs between reciprocal cross-pollinations is supported by the structure analysis of these proteins. L-type LecRLK contains a legume lectin-like extracellular domain, and G-type LecRLK has a α-mannose binding bulb lectin domain, while C-type LecRLKs are characterized due to the presence of calcium-dependent carbohydrate- binding domain [42]. G-type LecRLKs were historically known as SRKs, since they hold the D-mannose binding lectin (B_lectin) and catalytic domain of the serine/threo- nine kinases. a similar SRK gene (Camellia_sinensis_newGene_13508) from tea plant which differently expressed between self- and cross-pollinated pistils and might contribute to the signal transduction of SI in tea plant. In general, the SRK genes function in SI through the diversity of S domain. Therefore, the S domain of the SRK gene should be identified in different tea cultivars to explore the role of SRK on SI process of tea. The previous studies have identified a LSI or an ovarian sterility (OS) type controlling self-incompatibility in tea plants [19, 20]. The same phenomenon was also observed in our study. However, the molecular mechanism of this SI system remained unclear until Zhang et al. [21, 45] SRK genes have a S domain which is responsible for SI in Brassicaceae [15, 43]. Recently, these genes were also reported to confer abiotic stress tolerance and delay dark-induced leaf senescence in rice [44]. Here, we screened Ma et al. BMC Genomics (2018) 19:289 Page 10 of 12 Fig. 9 The qRT-PCR verification for RNA-Seq analysis. * means different significantly (P < 0.05) proposed a gametophytic SI mechanism based on S- RNase control in tea plant. Discussion Unexpectedly, S-RNase gene was not found in tea plant in the present study, but three DEGs were identified in comparison between self- and cross-pollinated pistils: G-type LecRLK, MCU2 and UGT74B1. Pollen tube reception, the crosstalk be- tween the male and female gametophytes when pollen tubes arrive at the synergid cells of the ovule in flower- ing plants, mutation of TURAN(TUN) and EVAN(EVN) genes led to overgrowth of the pollen tubes inside the female gametophyte and inhibited the rupture of pollen tubes. TUN encodes a UGT superfamily protein and is required for pollen tube growth and integrity by affecting the stability of the pollen-specific FERONIA RLKs [46, 47]. In this work, whether the UGT74B1 and G-type RLK genes work together on fertilization in tea plant remains unknown. Nevertheless, we can suggest that both of the genes may codetermine the SI mechanism in tea plant. It is difficult to explain that G-type LecRLK, MCU2 and UGT74B1 showed so different expression patterns be- tween self-pollinations. It may be due to the variety differ- ence of tea plants. More cultivars should be adopted to detect the expression of these genes in self- and cross- pollinations to interpret their roles in SI. Besides, function analysis through transgenic test to clarify the mechanism of these two genes in SI will be a good way in the future if more studies can be conducted to overcome the barriers in tea plant transformation. Our study suggests a dis- tinctive mode of action of SI in tea, and the results therein provide new guidance and reference for exploration of SI mechanism in tea. Page 11 of 12 Page 11 of 12 Ma et al. BMC Genomics (2018) 19:289 Funding Thi k This work was supported by the National Natural Science Foundation of China (31470690, 31570689) and the China Earmarked Fund for Modern Agro-industry Technology Research System (CARS-19). The funders had no role in study design, data collection, analysis and interpretation, or preparation of the manuscript. This work was supported by the National Natural Science Foundation of China (31470690, 31570689) and the China Earmarked Fund for Modern Agro-industry Technology Research System (CARS-19). The funders had no role 11. Qiao H, Wang F, Zhao L, Zhou J, Lai Z, Zhang Y, Robbins TP, Xue Y. The F- box protein AhSLF-S2 controls the pollen function of S-RNase–based self- incompatibility. Plant Cell. 2004;16(9):2307–22. y y y in study design, data collection, analysis and interpretation, or preparation of the manuscript. 12. Williams JS, Natale CA, Wang N, Li S, Brubaker TR, Sun P. Kao T-h. Four previously identified Petunia inflata S-locus F-box genes are involved in pollen specificity in self-incompatibility. Mol Plant. 2014;7(3):567–9. References 1. Newbigin E, Anderson MA, Clarke AE. Gametophytic self-incompatibility systems. Plant Cell. 1993;5(10):1315. 1. Newbigin E, Anderson MA, Clarke AE. Gametophytic self-incompatibility systems. Plant Cell. 1993;5(10):1315. 1. Newbigin E, Anderson MA, Clarke AE. Gametophytic self-incompatibility systems. Plant Cell. 1993;5(10):1315. Additional file 1: Figure S1. Pollen appearance and activity between ‘Fudingdabai’ and ‘Yulv’ in vitro. A Pollen germination and phenotype of ‘Fudingdabai’ and ‘Yulv’. B Pollen germination rate and average length of pollen tubes of ‘Fudingdabai’ and ‘Yulv’. (TIF 1137 kb) 2. Charlesworth D. Evolution of homomorphic sporophytic self-incompatibility. Heredity. 1988;60(3):445–53. 3. McClure BA, Gray JE, Anderson MA, Clarke AE. Self-incompatibility in Nicotiana alata involves degradation of pollen rRNA. Nature. 1990;347(6295):757–60. Additional file 2: Figure S2. Fluorescence of pollen tubes in self- and cross-pollinated pistils of tea plants at 48 h. “Top” and “Base” means the stigma and the base of the style of tea flower, respectively. Arrows indicate the pollen tubes with fluoresce. (TIF 4517 kb) 4. Li W, Chetelat RT. The role of a pollen-expressed Cullin1 protein in gametophytic self-incompatibility in solanum. Genetics. 2014;196(2):439–42. 5. Tao R, Yamane H, Sassa H, Mori H, Gradziel TM, Dandekar AM, Sugiura A. Identification of stylar RNases associated with gametophytic self- incompatibility in almond (Prunus dulcis). Plant Cell Physiol. 1997;38(3):304–11. Additional file 3: Figure S3. Gene Ontology enrich analysis of DEGs between unpollinated and pollinated samples. (TIF 755 kb) Additional file 3: Figure S3. Gene Ontology enrich analysis of DEGs between unpollinated and pollinated samples. (TIF 755 kb) 6. Mariette S, Tavaud M, Arunyawat U, Capdeville G, Millan M, Salin F. Population structure and genetic bottleneck in sweet cherry estimated with SSRs and the gametophytic self-incompatibility locus. BMC Genet. 2010; 11(1):77. 6. Mariette S, Tavaud M, Arunyawat U, Capdeville G, Millan M, Salin F. Population structure and genetic bottleneck in sweet cherry estimated with SSRs and the gametophytic self-incompatibility locus. BMC Genet. 2010; 11(1):77. Authors’ contributions QM performed pollination experiment, RNA extraction, RNA-Seq analysis and drafted the manuscript. CC cultivated the tea plants and participated in pollination experiment and samples collection. ZZ was involved in samples collection and detected the pollen activity of tea flowers. ZZ contributed to samples collection and observation of pollen tubes fluorescence. HL conducted the ion assay and edited the figures in the manuscript. QZ carried out qRT-PCR experiment. XC was involved in the study design and RNA-Seq analysis. KS performed statistical analysis and participated in the revision and finalization of the manuscript. XL conceived of the study, participated in its design and coordination, and helped to draft the manuscript. All authors read and approved the final manuscript. 15. Takasaki T, Hatakeyama K, Suzuki G, Watanabe M, Isogai A, Hinata K. The S receptor kinase determines self-incompatibility in Brassica stigma. Nature. 2000;403(6772):913–6. 16. Nasrallah JB, Nasrallah ME. Pollen-stigma signaling in the Sporophytic self- incompatibility response. Plant Cell. 1993;5(10):1325. 17. Nasrallah JB, Yu S-M, Nasrallah ME. Self-incompatibility genes of Brassica oleracea: expression, isolation, and structure. PNAS. 1988;85(15):5551–5. 18. Takayama S, Shiba H, Iwano M, Shimosato H, Che F-S, Kai N, Watanabe M, Suzuki G, Hinata K, Isogai A. The pollen determinant of self-incompatibility in Brassica campestris. PNAS. 2000;97(4):1920–5. 19. Chen X, Hao S, Wang L, Fang W, Wang Y, Li X. Late-acting self- incompatibility in tea plant (Camellia sinensis). Biologia. 2012;67(2):347–51. Availability of data and materials The datasets generated and/or analysed during the current study are l bl h S R d h (h // b l h / /) 13. Kachroo A, Schopfer CR, Nasrallah ME, Nasrallah JB. Allele-specific receptor- ligand interactions in Brassica self-incompatibility. Science. 2001;293(5536): 1824–6. available in the Sequence Read Archive (https://www.ncbi.nlm.nih.gov/sra/) with the accession number of SRR3290055. 14. Stein JC, Howlett B, Boyes DC, Nasrallah ME, Nasrallah JB. Molecular cloning of a putative receptor protein kinase gene encoded at the self- incompatibility locus of Brassica oleracea. PNAS. 1991;88(19):8816–20. Publisher’s Note The present study revealed that cross-pollination could promote the growth of pollens in styles and Ca2+ and K+ are involved in signal transduction in SI process of tea plants, and also G-type LecRLK and UGT74B1 may function together in controlling SI in tea plants. However, the specific role of these genes in SI process needs further identification. Our study will help understand the SI mechanism of tea plant further. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Ethics approval and consent to participate Tea plants used in this study were cultivated in tea germplasm repository of Tea Research Institute of Fujian Academy of Agricultural Sciences (FAAS). This study was permitted by FAAS and conducted in accordance with stipulations of FAAS. 20. Wachira F, Kamunya S. Pseudo-self-incompatibility in some tea clones (Camellia sinensis (L.) O. Kuntze). J Hort Sci Biotech. 2005;80(6):716–20. 21. Zhang C-C, Wang L-Y, Wei K, Wu L-Y, Li H-L, Zhang F, Cheng H, Ni D-J. Transcriptome analysis reveals self-incompatibility in the tea plant (Camellia sinensis) might be under gametophytic control. BMC Genomics. 2016;17(1):359. Abbreviations DEGs: Differentially expressed genes; GSI: Gametophytic self-incompatibility; G-type RLK: G-type lectin S-receptor-like serine/threonine-protein kinase; LSI: Late-acting self-incompatibility system; MCU2: Mitochondrial calcium uniporter protein 2; SI: Self-incompatibility; SLG: S-Locus glycoprotein gene; SRK: S-Locus receptor kinase; SSI: Sporophytic self-incompatibility; UGT74B1: UDP-glycosyltransferase 74B1 7. Vieira J, Ferreira PG, Aguiar B, Fonseca NA, Vieira CP. Evolutionary patterns at the RNase based gametophytic self-incompatibility system in two divergent Rosaceae groups (Maloideae and Prunus). BMC Evol Biol. 2010;10(1):200. 7. Vieira J, Ferreira PG, Aguiar B, Fonseca NA, Vieira CP. Evolutionary patterns at the RNase based gametophytic self-incompatibility system in two divergent Rosaceae groups (Maloideae and Prunus). BMC Evol Biol. 2010;10(1):200. 8. Schopfer CR, Nasrallah ME, Nasrallah JB. The male determinant of self- incompatibility in Brassica. Science. 1999;286(5445):1697–700. 8. Schopfer CR, Nasrallah ME, Nasrallah JB. The male determinant of self- incompatibility in Brassica. Science. 1999;286(5445):1697–700. 9. Takayama S, Isogai A. Self-incompatibility in plants. Annu Rev Plant Biol. 2005;56:467–89. 10. Sijacic P, Wang X, Skirpan AL, Wang Y, Dowd PE, McCubbin AG, Huang S. Kao T-h. Identification of the pollen determinant of S-RNase-mediated self- incompatibility. Nature. 2004;429(6989):302–5. Author details 1 h 1Tea Research Institute, Nanjing Agricultural University, Nanjing 210095, China. 2Tea Research Institute, Fujian Academy of Agricultural Sciences, Ningde 355015, China. 3Department of Plant Science, University of Manitoba, Winnipeg R3T 2N2, Canada. 355015, China. 3Department of Plant Science, University of Manitoba, Winnipeg R3T 2N2, Canada. Received: 26 July 2017 Accepted: 13 April 2018 Received: 26 July 2017 Accepted: 13 April 2018 Competing interests Th h d l h 22. Trapnell C, Roberts A, Goff L, Pertea G, Kim D, Kelley DR, Pimentel H, Salzberg SL, Rinn JL, Pachter L. Differential gene and transcript expression The authors declare that they have no competing financial interests. Page 12 of 12 Ma et al. BMC Genomics (2018) 19:289 analysis of RNA-seq experiments with TopHat and cufflinks. Nat Protoc. 2012;7:562. analysis of RNA-seq experiments with TopHat and cufflinks. Nat Protoc. 2012;7:562. 23. Ghosh S, Chan C. Analysis of RNA-Seq data using TopHat and cufflinks. Methods Mol Biol. 2015;1374:339–61. 24. Altschul SF, Madden TL, Schäffer AA, Zhang J, Zhang Z, Miller W, Lipman DJ. Gapped BLAST and PSI-BLAST: a new generation of protein database search programs. Nucleic Acids Res. 1997;25(17):3389–402. 25. Deng Y, Li J, Wu S, Zhu Y, Chen Y, He F. Integrated nr database in protein annotation system and its localization. Comput Eng. 2006;32(5):71–4. 26. Tatusov RL, Galperin MY, Natale DA, Koonin EV. The COG database: a tool for genome-scale analysis of protein functions and evolution. Nucleic Acids Res. 2000;28(1):33–6. 27. Apweiler R, Bairoch A, Wu CH, Barker WC, Boeckmann B, Ferro S, Gasteiger E, Huang H, Lopez R, Magrane M. UniProt: the universal protein knowledgebase. Nucleic Acids Res. 2004;32(1):D115–9. 28. Ashburner M, Ball CA, Blake JA, Botstein D, Butler H, Cherry JM, Davis AP, Dolinski K, Dwight SS, Eppig JT. Gene ontology: tool for the unification of biology. Nat Genet. 2000;25(1):25–9. 29. Florea L, Song L, Salzberg SL. Thousands of exon skipping events differentiate among splicing patterns in sixteen human tissues. F1000Research. 2013;2:188. 30. Anders S, Huber W. Differential expression analysis for sequence count data. Genome Biol. 2010;11(10):R106. 30. Anders S, Huber W. Differential expression analysis for sequence count data. Genome Biol. 2010;11(10):R106. 31. Reiner A, Yekutieli D, Benjamini Y. Identifying differentially expressed genes using false discovery rate controlling procedures. Bioinformatics. 2003;19(3): 368–75. 32. Livak KJ, Schmittgen TD. Analysis of relative gene expression data using real- time quantitative PCR and the 2−ΔΔCT method. Methods. 2001;25(4):402–8. 33. Franklin-Tong N. Self-incompatibility: calcium signalling in Brassica. Nat Plants. 2015;1:15129. 34. Eaves DJ, Flores-Ortiz C, Haque T, Lin Z, Teng N, Franklin-Tong VE. Self- incompatibility in Papaver: advances in integrating the signalling network: Portland Press Limited; 2014. 35. Iwano M, Ito K, Fujii S, Kakita M, Asano-Shimosato H, Igarashi M, Kaothien- Nakayama P, Entani T, Kanatani A, Takehisa M. Calcium signalling mediates self-incompatibility response in the Brassicaceae. Nat Plants. 2015;1:15128. 36. Competing interests Th h d l h Jiang X, Gao Y, Zhou H, Chen J, Wu J, Zhang S. Apoplastic calmodulin promotes self-incompatibility pollen tube growth by enhancing calcium influx and reactive oxygen species concentration in Pyrus pyrifolia. Plant Cell Rep. 2014;33(2):255–63. 37. Kirichok Y, Krapivinsky G, Clapham DE. The mitochondrial calcium uniporter is a highly selective ion channel. Nature. 2004;427(6972):360–4. 38. Campbell K, Swann K. Ca2+ oscillations stimulate an ATP increase during fertilization of mouse eggs. Dev Biol. 2006;298(1):225–33. 39. Dumollard R, Duchen M, Sardet C. Calcium signals and mitochondria at fertilisation. In: Seminars in cell & developmental biology: 2006: Elsevier; 2006. p. 314–23. 40. Miao Y-L, Williams CJ. Calcium signaling in mammalian egg activation and embryo development: the influence of subcellular localization. Mol Rep Dev. 2012;79(11):742–56. 41. Wu J, Wang S, Gu Y, Zhang S, Publicover SJ, Franklin-Tong VE. Self- incompatibility in Papaver rhoeas activates nonspecific cation conductance permeable to Ca2+ and K+. Plant Physiol. 2011;155(2):963–73. 42. Vaid N, Macovei A, Tuteja N. Knights in action: lectin receptor-like kinases in plant development and stress responses. Mol Plant. 2013;6(5):1405–18. 43. Goring DR, Rothstein SJ. The S-locus receptor kinase gene in a self- incompatible Brassica napus line encodes a functional serine/threonine kinase. Plant Cell. 1992;4(10):1273–81. 44. Chen L-J, Wuriyanghan H, Zhang Y-Q, Duan K-X, Chen H-W, Li Q-T, Lu X, He S-J, Ma B, Zhang W-K. An S-domain receptor-like kinase, OsSIK2, confers abiotic stress tolerance and delays dark-induced leaf senescence in rice. Plant Physiol. 2013;163(4):1752–65. 45. Zhang C-C, Tan L-Q, Wang L-Y, Wei K, Wu L-Y, Zhang F, Cheng H, Ni D-J. Cloning and characterization of an S-RNase gene in Camellia sinensis. Sci Hortic. 2016;207:218–24. 46. Lindner H, Kessler SA, Müller LM, Shimosato-Asano H, Boisson-Dernier A, Grossniklaus U. TURAN and EVAN mediate pollen tube reception in Arabidopsis Synergids through protein glycosylation. PLoS Biol. 2015;13(4):e1002139. 47. Escobar-Restrepo J-M, Huck N, Kessler S, Gagliardini V, Gheyselinck J, Yang W-C, Grossniklaus U. The FERONIA receptor-like kinase mediates male-female interactions during pollen tube reception. Science. 2007;317(5838):656–60.
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Foreword from Handling Editor - 7th Edition
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Recommended Citation Recommended Citation Dwiranti, Astari (2020). Foreword from Handling Editor - 7th Edition. ASEAN Journal of Community Engagement, 4(1). Available at: https://doi.org/10.7454/ajce.v4i1.1097 Available at: https://doi.org/10.7454/ajce.v4i1.1097 Foreword from Handling Editor - 7th Edition Foreword from Handling Editor - 7th Edition Astari Dwiranti astari.dwiranti@sci.ui.ac.id Follow this and additional works at: https://scholarhub.ui.ac.id/ajce Part of the Social and Behavioral Sciences Commons Recommended Citation Recommended Citation This work is licensed under a Creative Commons Attribution-Share Alike 4.0 License. This Front Matter is brought to you for free and open access by the Universitas Indonesia at ASEAN Journal of Community Engagement. It has been accepted for inclusion in ASEAN Journal of Community Engagement. ASEAN Journal of Community ASEAN Journal of Community Engagement Engagement Volume 4 Number 1 July Article 1 7-31-2020 Foreword from Handling Editor - 7th Edition Foreword from Handling Editor - 7th Edition Astari Dwiranti astari.dwiranti@sci.ui.ac.id Follow this and additional works at: https://scholarhub.ui.ac.id/ajce Part of the Social and Behavioral Sciences Commons Recommended Citation Recommended Citation Dwiranti, Astari (2020). Foreword from Handling Editor - 7th Edition. ASEAN Journal of Community Engagement, 4(1). Available at: https://doi.org/10.7454/ajce.v4i1.1097 Creative Commons License ASEAN Journal of Community ASEAN Journal of Community Engagement Engagement Volume 4 Number 1 July Article 1 7-31-2020 Foreword from Handling Editor - 7th Edition Foreword from Handling Editor - 7th Edition Astari Dwiranti astari.dwiranti@sci.ui.ac.id ASEAN Journal of Community ASEAN Journal of Community Engagement Engagement Volume 4 Number 1 July Article 1 7-31-2020 ASEAN Journal of Community ASEAN Journal of Community Engagement Engagement Volume 4 Number 1 July Article 1 7-31-2020 Foreword from Handling Editor - 7th Edition Foreword from Handling Editor - 7th Edition Dear Readers, It is very happy for us to present this edition, Volume 4 Number 1, July 2020. Amid the concerns of the Covid-19 pandemic, which influences human life around the globe, we are honor to select and publish the best submitted-papers in the field of community engagement (5 papers from Indonesia, 3 Papers from Philippines, 1 Paper from Portugal, 1 Paper from Australia, 1 Paper from Thailand, and 1 Paper from Malaysia and Vietnam). At the first insight, we present an article with type of Research Paper, Review Articles, and Case- based Articles. For Research Paper, we have excellent of 8 articles. First article about creative economy clinic. The authors: Andri Zainal, T. Citra Nisa Farza, Khairunnisa Harahap, and Pasca Dwi Putra writes, “Developing an on-campus creative economy clinic to elevate the quality of existing community service program”. The article is to highlights the potential outcomes of establishing an in-campus creative economy clinic that ensuring the business sustainability of MSMEs in the disruptive technology era. Initial assessment related to the needs of MSME is further required as a strategic step for the development of the ecosystem of related creative economy clinic based on competitive advantage attached to each university Next, we present the paper an enriching creative communities through literature, “Enriching creative communities through young adult (YA) literature: a content analysis of zines from Philippine High School for the Arts” written by Reya Mari Soriaga Veloso. This article conclude that YA zines provide alternative creative community to the youth, are a form of counter- storytelling, and a means for sociological theorizing—all of which are necessary functions for enriching creative communities among the youth. On the topic of health, we present articles by the author Hugo Oliveira and Jorge Bonito. with the title “Health education projects in Portuguese schools: A multicases study”. Authors presents there is a lack of instruments and methodologies able to record the behavioral changes developed within the scope of health education, while simultaneously stimulating the reflection on these behavioural changes and their causes. Next article, still with Research Paper, written by Sri Ismiyati Damayanti, Simparmin Ginting, Otik Nawansih, and Siti Hudaidah, with the article “Implementation of biogas-based energy security program and evaluation of its sustainability in Kediri Village, Pringsewu District, Lampung Province”. Creative Commons License This work is licensed under a Creative Commons Attribution-Share Alike 4.0 License. This work is licensed under a Creative Commons Attribution-Share Alike 4.0 License. This Front Matter is brought to you for free and open access by the Universitas Indonesia at ASEAN Journal of Community Engagement. It has been accepted for inclusion in ASEAN Journal of Community Engagement. This Front Matter is brought to you for free and open access by the Universitas Indonesia at ASEA Community Engagement It has been accepted for inclusion in ASEAN Journal of Community Eng Community Engagement. It has been accepted for inclusion in ASEAN Journal of Community Eng Dear Readers, Authors concluded that the Biogas-based Energy Security Program has succeeded in making the community awareness, accept and apply the technology of processing cow manure into biogas, where the people whose houses have biogas flow, all the fuel needs for cooking and electricity off, 100% have been met by biogas. A discussion of current issues about Covid-19 written by Yeni, Najmah, and Sharyn Graham Davies. The paper “Predicitive modeling, empowering women, and Covid-19 in South Sumatra, Indonesia” shows modelling indicates that over 1,000 people had Covid-19 by the end of April, reaching over 150,000 by the end of May, and over a third of South Sumatra’s population is likely to be infected by the end of June. Multiple interventions are needed to reduce cases and flatten the curve. Women are key to flattening the curve and must be empowered to undertake actions from a familial base. to be infected by the end of June. Multiple interventions are needed to reduce cases and flatten the curve. Women are key to flattening the curve and must be empowered to undertake actions from a familial base. On the topic of kids related to protection, we present a paper “Self protection and stop bullying campaign for kids at RPTRA Sungai Bambu, Tanjung Priok, Jakarta Utara” written by Suraya Mansur. The result shown that children who take part in community service activities shown an increase level of knowledge and awareness of self-protection by following the instructions in the song “Sentuhan Boleh Sentuhan Tidak Boleh” (What You Can Touch, and What You Can’t Touch). These approach must be done together with other friends, for more mature children to guide younger children. On the topic of kids related to protection, we present a paper “Self protection and stop bullying campaign for kids at RPTRA Sungai Bambu, Tanjung Priok, Jakarta Utara” written by Suraya Mansur. The result shown that children who take part in community service activities shown an increase level of knowledge and awareness of self-protection by following the instructions in the song “Sentuhan Boleh Sentuhan Tidak Boleh” (What You Can Touch, and What You Can’t Touch). These approach must be done together with other friends, for more mature children to guide younger children. Another article from health, is written by Artemio Morado Gonzales Jr. The article “Empowering the lowland indigenous community through child health and nutrition program in Occidental Mindoro Province, Philippines”. Dear Readers, The common tools used from this article were seating arrangement, flipcharting, props, social hours, and recreation. In terms of the evaluation of the program, the child health remains poor despite of the effort of the different blocks that is working in the health system. Thus, this program could enhance their health knowledge and practice in other forms of extension modalities. Development of technology for dairy cattle production, is discussed in a paper entitled “Intensifying forage legumes strata system technology through dairy cattle production” written by Marcos E. Bollido, Teresa B. Polbos, and Feleciano R. Bejar. These technologies was implemented in collaboration with the Department of Agriculture and Local Government Unit of San Jorge, Samar. Beneficiaries were selected based on the set criteria and qualifications. For Review Articles we have 3 selected papers. First, about Social Life Cycle Assessment (S- LCA) is written in the article “Enhancing the community engagement of Indonesian Palm Oil Companies through the implementation of the Social Life Cycle Assessment (SLCA)” by Indah Budiani. The study highlights importance of community stakeholders’ inclusion in decision- making processes as the means to prevent conflict, and to maintain company reputation. Other approaches such as capacity building and social economic development can be also effective as long as there is a thorough assessment in advance and participation of local community in developing the intervention plan. Next article is from Thailand with the topic of cross-border development in Universities, with the title “Cross-border development - a long-term role for Universities” by Robert Brian Smith and Nucharee Nuchkoom Smith. The results showed that there are three issues were identified as priority areas to be addressed: quality of higher education, complex government bureaucracies and ineffective on the job training. This will require universities to provide high quality offerings which are relevant to their community and the wider world market. Third article for Review Article is written by Ma Tin Cho Mar and Pham Huong Trang, with the title of “Malay minorities in The Tenasserim coast”. This paper discussed Malay Minorities in the Tenasserim Coast and then Tanintharyi Division is an administrative region of Myanmar at present. This study methodology combined two complementary approaches for identifying, analyzing and understanding patterns of knowledges sharing within complex social systems. Furthermore, the paper discussed the significance attached to the aspects of human migration in Southeast Asia. Dear Readers, Last one article for Case-based Articles is written by Hanna Lianti, Novi Kurnia, Kshetra Rinaldhy, Amanda Safira Aji, M Febriadi Ismet, and Rizky Amaliah. This article about knowledge regarding Biliary Atresia, with the title of “Analysis of knowledge regarding Biliary Atresia among healthcare providers and laypersons in East Jakarta after educational intervention”. The result are there were significant increase in the median value between pre-test and post-test knowledge scores in both healthcare providers and laypersons groups. We want to express our thanks to the Directorate of Community Engagement and Empowerment, Universitas Indonesia, and reviewers who gave inputs and contributions to improve the quality of the articles. Our greatest thanks are also due to Azhar Firdaus for helping us with the publication process and to the Directorate of Administration, Data, and Management of Research Product and Innovation (DADPPRI UI) for providing a journal development grant and proofread assistance through Enago. Finally, we hope that readers enjoy the articles that we present in this edition. We hope that readers enjoy exploring the papers on this edition and keep healthy and safe. Best Regards, https://scholarhub.ui.ac.id/ajce/ Astari Dwiranti, Ph.D. Handling Editor - ASEAN Journal of Community Engagement Handling Editor - ASEAN Journal of Community Engagement https://scholarhub.ui.ac.id/ajce/
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Knowledge, Attitudes and Perceptions towards COVID-19 Vaccinations: A Cross-Sectional Survey in Pakistan
Medicina
2,023
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9,361
Article Knowledge, Attitudes and Perceptions towards COVID-19 Vaccinations: A Cross-Sectional Survey in Pakistan Abbas 1, Saima Mushtaq 2, Atika Mansoor 3, Ivan R. Green 4 , Tauqeer Hussain Mallhi 5 , and Amjad Khan 1,* Asima Bibi 1, Sameen Abbas 1, Saima Mushtaq 2, Atika Mansoor 3, Ivan R. Green 4 , Tauqeer Hussain Mallhi 5 , Yusra Habib Khan 5 and Amjad Khan 1,* 1 Department of Pharmacy, Quaid-i-Azam University, Islamabad 45320, Pakistan 1 Department of Pharmacy, Quaid-i-Azam University, Islamabad 45320, Pakistan 2 Department of Healthcare Biotechnology, Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad 44000, Pakistan 3 Institute of Biomedical and Genetic Engineering (IBGE), KRL Hospital, Islamabad 44000, Pakistan 4 Department of Chemistry and Polymer Science, University of Stellenbosch, Matieland, Stellenbosch 7600, South Africa 5 Department of Clinical Pharmacy, College of Pharmacy, Jouf University, Sakaka 72388, Saudi Arabia * Correspondence: amjadkhan@qau.edu.pk 1 Department of Pharmacy, Quaid-i-Azam University, Islamabad 45320, Pakistan 2 Department of Healthcare Biotechnology, Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad 44000, Pakistan 3 Institute of Biomedical and Genetic Engineering (IBGE), KRL Hospital, Islamabad 44000, Pakistan 4 Department of Chemistry and Polymer Science, University of Stellenbosch, Matieland, Stellenbosch 7600, South Africa 5 Department of Clinical Pharmacy, College of Pharmacy, Jouf University, Sakaka 72388, Saudi Arabia * Correspondence: amjadkhan@qau.edu.pk 5 Department of Clinical Pharmacy, College of Pharmacy, Jouf University, Sakaka 72388, Saudi Arabia * Correspondence: amjadkhan@qau.edu.pk Abstract: Background and Objectives: Several vaccines have been approved for the prevention of the coronavirus disease, discovered on 31 December in Wuhan, China. Pakistan procured vaccines from various countries. However, the lack of knowledge and reluctance of the general population to embrace the use of the vaccines are considered to be the major determinant of the slow vaccination rate. Hence, it is necessary to evaluate the willingness of the general population about their perception of the COVID-19 vaccination. Materials and Methods: A cross sectional survey based on a self-structured questionnaire comprising 18 questions was conducted (from 21 April–21 June) on 400 Pakistani participants to evaluate their knowledge, attitude, and perception towards the COVID-19 vaccination. Chi-square independent t-test and one-way Anova including a multiple step wise linear regression were used to draw conclusions about the results. p < 0.05 was considered significant. Results: A total of 400 participants responded in the knowledge, attitude, and perception (KAP) survey of which 46.5% were female and 53.5% were male. The mean age of participants was 36.08 years. Academic Editor: Gennaro De Pascale Keywords: COVID-19; vaccine; knowledge; attitude; perception; survey; questionnaire Received: 29 October 2022 Revised: 14 December 2022 Accepted: 15 December 2022 Published: 31 January 2023 Keywords: COVID-19; vaccine; knowledge; attitude; perception; survey; questionnaire Article Knowledge, Attitudes and Perceptions towards COVID-19 Vaccinations: A Cross-Sectional Survey in Pakistan This survey showed a poor knowledge (50.5%), a fair attitude (75.1%) and a poor perception (58.1%) towards the COVID-19 vaccination. Higher mean knowledge and attitude scores were reported in the age group 21–40, females, and unmarried urban citizens. Regression analysis showed that age, education, residence, and employment status influenced the knowledge and perception score to a considerable extent. Conclusions: The findings reflect an inadequate knowledge and perception on the one hand, but a better attitude towards the COVID-19 vaccination. This knowledge attitude and perception (KAP) survey will help in better understanding the opinion of the general population towards vaccination, and will be useful for policy makers and health care authorities aiming to increase the vaccination rate. medicina medicina medicina Citation: Bibi, A.; Abbas, S.; Mushtaq, S.; Mansoor, A.; Green, I.R.; Mallhi, T.H.; Khan, Y.H.; Khan, A. Knowledge, Attitudes and Perceptions towards COVID-19 Vaccinations: A Cross-Sectional Survey in Pakistan. Medicina 2023, 59, 272. https://doi.org/10.3390/ medicina59020272 Citation: Bibi, A.; Abbas, S.; Mushtaq, S.; Mansoor, A.; Green, I.R.; Mallhi, T.H.; Khan, Y.H.; Khan, A. Knowledge, Attitudes and Perceptions towards COVID-19 Vaccinations: A Cross-Sectional Survey in Pakistan. Medicina 2023, 59, 272. https://doi.org/10.3390/ medicina59020272 Academic Editor: Gennaro De Pascale 1. Background After the Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS) outbreak, a new virus was discovered on 31 December in Wuhan, China, named 2019 n-CoV by the World Health Organization (WHO), and later named SARS- CoV-2 by the International Committee on the taxonomy of viruses [1]. The WHO declared COVID-19 to be the sixth Public Health Emergency of International Concern (PHEIC), and later declared it to be a global pandemic on 11 March 2020 (WHO, 2005). The first COVID-19 case was reported in Pakistan on 26 February 2020 [2]. Since then, the number of cases increased rapidly. Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). https://www.mdpi.com/journal/medicina Medicina 2023, 59, 272. https://doi.org/10.3390/medicina59020272 Medicina 2023, 59, 272 2 of 14 Persons infected with COVID-19 develop the common conditions of fever, cough, shortness of breath, sore throat, nasal congestion, weakness, fatigue, and dyspnea [3–5]. Various risk factors are involved with the complexity of COVID-19. These risk factors are: old age, respiration distress, and various chronic co-morbid conditions [6,7] Other risk factors includes respiratory distress, sepsis, metabolic acidosis, arrhythmia heart failure, kidney failure, and hypoxic encephalopathy [8]. Treatment strategies were initially mainly focused on corticosteroids, blood thinners, and neutralizing antibodies, due to the lack of a specific cure, such as vaccination [9]. After an extensive development phase, vaccination became one of the best treatment strategies recommended by the WHO to generate herd immunity in the general population [10,11]. Despite supply challenges, the Pakistan government acquired 40 million COVID-19 vaccines from China, the WHO, USA, UK and Germany, in order to be able to vaccinate an estimated 70 million people [12–16]. Statistics shared by the Government of Pakistan showed that only 18.2% of the Pakistan population is fully vaccinated [17]. Pakistan has a history of a relatively low vaccination rate for a variety of vaccine preventable diseases, such as HBV and polio [18]. Unless this COVID-19 low vaccination rate is not seriously addressed, it will take an unnecessarily longer time for the general population to return a semblance of normalcy from this pandemic [19]. 2.2. Study Setting The study was conducted on the general population of all the provinces (Punjab, Sindh, Khyber Pakhtunkhwa, Balochistan) of Pakistan. 2.1. Study Design Cross sectional studies were performed to assess knowledge, attitude, and perception of the Pakistani population towards the COVID-19 vaccination. 1. Background p It is well known that, generally, any new medical intervention has its own acceptabil- ity rate among the general population, and thus the acceptance of the COVID-19 vaccine, along with its distribution and proper utilization to every member of society, is also very important. [20]. Previous reported data showed that those reluctant to take the COVID-19 vaccination due to safety concerns totaled, in the USA, 33% of general participants and 50% of health care workers [21]; in Turkey, 45.3% of general participants and 42.2% of health care workers; and in Oman, 23% of general respondents and 40% of healthcare workers [22–26]. In the USA, its acceptance was 50%, in France its acceptance was only 62% [20,27]. While in Italy, acceptance of the COVID-19 vaccination was 59% [28,29]. Similarly, one of China’s surveys about COVID-19 vaccination declared that only one half, that is 54% pf the population, was willing to have vaccination [30]. Several important factors, such as health knowledge, serve as being important for the participants in increasing their acceptance, as more knowledge by the general population towards breakouts such as the COVID-19 pandemic, its vaccination and potential benefits, coupled with its precautionary measures, contributes in a better implemen- tation of health system facilities [30,31]. Similarly, attitude and perception are the two primary cognitive factors that play a vital role in the vaccination coverage rate of COVID-19. Knowledge, attitude, and perception (KAP) surveys mostly help to identify knowl- edge gaps and behavior patterns of the general population on the basis of their socio- demographics, in order to implement effective public health interventions [32]. This study aimed to determine the knowledge, acceptance, and perception of the COVID-19 vaccine among the Pakistani population. 2.7. Questionnaires Development and Validation A self-structured questionnaire was designed based on a previous literature review. After an extensive literature review, the questionnaire was designed in English [33]. The English version of the questionnaire was translated into Urdu by using a back-to-back translation procedure [34]. This questionnaire was tested for its reliability and internal consistency. The internal consistency of the knowledge, attitude, and perception (KAP) survey questionnaire calculated by Cronbach’s alpha was 0.720 for knowledge, 0.642 for attitude, and 0.629 for perception, and found to be in an acceptable range. An initial pilot study was performed among 20 participants to evaluate its acceptability and consistency, but these results were not included in the final study. 2.8. Scoring Criteria and Statistical Analysis The scoring criteria was based on the original bloom’s cut-off point used in previ- ous studies conducted on dengue fever anticipation in male people of the Maldives and Bangkok in 2007, as well as a KAP study performed on COVID-19 among Chronic Dis- ease Patients in Northwest Ethiopia in 2020 [35,36]. Criteria of bloom’s cut-off point were 80–100% (good), 60.0–79.0% (fair), and ≤59.0% (poor). In statistical analysis categorical variables were represented in form percentages and frequencies and Chi Square Indepen- dent was used to analyze significant association between demographics and knowledge, attitude, and perception. Independent t-test (for two groups) and one-way ANOVA (for more than two groups) were used to measure association within groups. Similarly, multiple linear regression model was used to analyze the impact of an independent variable over a dependent variable. The statistical software package for social sciences (IBM SPSS for Windows, Version 21.0. SPSS Inc., Chicago, IL, USA) was used to evaluate the data. p-value less than 0.05 are considered significant. 2.4. Inclusion and Exclusion Criteria Participants were 18 years or older and Pakistani residents, having an easy access to the Internet and were voluntary participants. People below the targeted age of 18 years were excluded from this study. 2.3. Study Duration The study was carried out from April–June 2021 through an online questionnaire, which was distributed on different social media platforms (e.g., Facebook and WhatsApp). During this time duration of April to June (3rd and 4th wave of COVID-19), a community- based national survey was not possible. So, relying on online social media links, the Medicina 2023, 59, 272 3 of 14 3 of 14 questionnaire was posted/reposted to local people living in different areas of Pakistan. In this online survey, answers to all questions was mandatory for final submission. questionnaire was posted/reposted to local people living in different areas of Pakistan. In this online survey, answers to all questions was mandatory for final submission. 2.4. Inclusion and Exclusion Criteria 2.5. Sample Size and Sampling Technique Initially, the convenient sampling technique was used for sample size estimation. In this survey, thousands of participants could be included, however, due to the limited time period, sample size was calculated from the estimated current population of Pakistan by using the Rao-soft calculator to have an idea of the least number of participants that must be included in this survey. The current population of Pakistan is 213,222,917 as per 2017 Census of Pakistan. With a 95% confidence interval, 50% population representation and 5% margin of error, a 385 sample size was calculated by using the Rao-soft calculator. However, data from 400 participants was collected. It was a limited sample size because of the limited time duration of survey during the 3rd and 4th wave. 2.6. Study Tool A self-structured 18-item questionnaire, along with the appropriate demographics, was prepared and divided into three sections. In addition to demographics, six questions explored knowledge about COVID-19 while eight questions focused on attitude and four questions focused on perception of participants towards the COVID-19 vaccination. 2.9. Ethical Approval This survey was conducted after ethical approval from the institutional research and ethics forum of Rawalpindi Medical University (Vide letter number: 64/IREF/RMU/2021, Medicina 2023, 59, 272 4 of 14 Dated 23 April 2021). Respondents were clearly informed about the purpose of the study and privacy of their data was also assured. 3.1. Demographics of Knowledge, Attitude and Perception Study Age, gender, marital status, employment, education status, and residence of partici- pants are articulated in Table 1. All these were categorical variables to facilitate statistical analysis in the form of frequencies and percentages to be performed. In all, 400 participants completed the survey. Both males 53.5% (n = 214) and females 46.5% (n = 186) participated in the study. The mean age of participants was 36.08 years. (S.D 15.54). The majority of the respondents were from age group 21–40 years. Most of the participants were urban 281 (70.2%) and married citizens 220 (55.0%). In the educational category, 43.22% (n = 172) of the participants had a higher education or below, while those with a graduate level of education were 30.3% (n = 121). Participants having a postgraduate level of education were 26.7% (n = 107). Participants having government jobs account for 20.3% (n = 81), non-government employees were 18.9% (n = 75), unemployed 16.9% (n = 67), retired 9.1% (n = 36), self-employed 8.0% (n = 32) and students 27.3% (n = 109). This classification illustrates a greater number of government employee participation in the study. Table 1. Demographic characteristics of study participants. Demographics Frequency (n) Percentages (%) Age <20 39 9.7 21–40 218 54.5 41–60 109 27.2 >61 34 8.5 Gender Female 186 46.5 Male 214 53.5 Marital status Unmarried 180 45 Married 220 55.0 Education level High school or below 172 43.2 Graduate 121 30.3 Postgraduate 107 26.7 Employment status Gov. employee 81 20.3 Non Gov. employee 75 18.9 Self employed 32 8.0 Student 109 27.3 Retired 36 9.0 Unemployed 67 16.9 Residence Urban 281 70.2 Rural 119 29.8 Note: number of participants (n); percentages (%) n = 400. Table 1. Demographic characteristics of study participants. Table 1. Demographic characteristics of study participants. 3.2. Frequency of Response to Knowledge Knowledge was evaluated by six questions about several aspects of the COVID-19 vaccination, with a corresponding scale ranging from 0–6. Responses were scored as 0 for no/don’t know and 1 for yes. Total score was calculated by the sum of six knowledge scores and ranged from 0–6. This led to the finding that 318 (79.5%) know about the COVID- 19 vaccination, 250 (62.5%) know about the effectiveness of the vaccination, 177 (44.3%) responded that it is unsafe to use an overdose of vaccination, 302 (75.5%) responded that Medicina 2023, 59, 272 5 of 14 wledge ut the 5 of 14 wledge ut the vaccination cannot cause allergic reactions, while 305 (76.2%) don’t know that the vaccine is recommended for pregnant women and 272 (68.0%) of the participants reported that vaccination is available in two doses with an additional booster dose becoming available at a later stage. Figure 1 also shows the response to knowledge. (44.3%) responded that it is unsafe to use an overdose of vaccination, 302 (75.5%) re- sponded that vaccination cannot cause allergic reactions, while 305 (76.2%) don’t know that the vaccine is recommended for pregnant women and 272 (68.0%) of the participants reported that vaccination is available in two doses with an additional booster dose becom- ing available at a later stage. Figure 1 also shows the response to knowledge. vaccination cannot cause allergic reactions, while 305 (76.2%) don’t know that the vaccine is recommended for pregnant women and 272 (68.0%) of the participants reported that vaccination is available in two doses with an additional booster dose becoming available at a later stage. Figure 1 also shows the response to knowledge. (44.3%) responded that it is unsafe to use an overdose of vaccination, 302 (75.5%) re- sponded that vaccination cannot cause allergic reactions, while 305 (76.2%) don’t know that the vaccine is recommended for pregnant women and 272 (68.0%) of the participants reported that vaccination is available in two doses with an additional booster dose becom- ing available at a later stage. Figure 1 also shows the response to knowledge. Figure 1. Response to knowledge of the vaccination. Figure 1. Response to knowledge of the vaccination. Figure 1. Response to knowledge of the vaccination. Figure 1. Response to knowledge of the vaccination. Figure 1. Response to knowledge of the vaccination. Figure 1. Response to knowledge of the vaccination. 3.3. Frequency of Response to Attitude A i d l d b i h 3.3. Frequency of Response to Attitude Frequency of Response to Perception Perception was assessed by four questions, which were scored as yes, no, do not know, and scaled as 0, for no/do not know and 1 was for a yes response. Scoring scale ranged from 0–4. Responses of participants showed that: 57.0% (n = 228) indicated that after taking the vaccination they should follow guidelines to combat new variants; 56.0% (n = 224) believe that COVID-19 can be eradicated by taking preventive measures instead Figure 2. Response to attitude of the vaccination. 3.4. Frequency of Response to Perception Perception was assessed by four questions, which were scored as yes, no, do not know, and scaled as 0, for no/do not know and 1 was for a yes response. Scoring scale ranged from 0–4. Responses of participants showed that: 57.0% (n = 228) indicated that after taking the vaccination they should follow guidelines to combat new variants; 56.0% (n = 224) believe that COVID-19 can be eradicated by taking preventive measures instead of vaccination; 79.5% (n = 318) indicated that they prefer to have the vaccination even if h i h l h i i d b h il d 60 0% ( 240) d d h h (a) Frequency of response to attitude of 5 questions (a) Frequency of response to attitude of 5 questions (b) Frequency of response to attitude of 3 questions (b) Frequency of response to attitude of 3 questions Figure 2. Response to attitude of the vaccination. (a tions; (b) Frequency of response to attitude of 3 que Figure 2. Response to attitude of the vaccination. ; ( ) q y p 3 4 F f R t P ti 3.4. Frequency of Response to Perception 3.3. Frequency of Response to Attitude A i d l d b i h 3.3. Frequency of Response to Attitude Attitude was evaluated by eight questions. Each question was scored as disagree, undecided and agree and scaled as 0, 1 and 2 respectively. Scoring scale ranged from 0– 16. In these eight questions of attitude assessment, 400 participants responded, out of which: 207 (51.8%) agreed that the vaccine is safe; 310 (77.5%) agreed that the vaccine is essential; 257 (64.3%) agreed that they will take the vaccination when it becomes available in Pakistan; 301 (75.3%) responded that they will encourage their friends, family, and rel- atives to get vaccinated; 215 (53.8%) agreed to the response that COVID-19 eradication without vaccination is impossible; 325 (81.3%) agreed that the vaccine should be circulated on a priority basis; 206 (51.5%) believed that by taking precautionary measures instead of vaccination COVID-19 could be eradicated; and 317 (79.3%) agreed that vaccination is their social responsibility to control the spread of COVID-19. Similarly, Figure 2 also shows response to attitude. Attitude was evaluated by eight questions. Each question was scored as disagree, undecided and agree and scaled as 0, 1 and 2 respectively. Scoring scale ranged from 0–16. In these eight questions of attitude assessment, 400 participants responded, out of which: 207 (51.8%) agreed that the vaccine is safe; 310 (77.5%) agreed that the vaccine is essential; 257 (64.3%) agreed that they will take the vaccination when it becomes available in Pakistan; 301 (75.3%) responded that they will encourage their friends, family, and relatives to get vaccinated; 215 (53.8%) agreed to the response that COVID-19 eradication without vaccination is impossible; 325 (81.3%) agreed that the vaccine should be circulated on a priority basis; 206 (51.5%) believed that by taking precautionary measures instead of vaccination COVID-19 could be eradicated; and 317 (79.3%) agreed that vaccination is their social responsibility to control the spread of COVID-19. Similarly, Figure 2 also shows response to attitude. Medicina 2023, 59, 272 Medicina 2022, 58, x FOR 6 of 14 of 14 (a) Frequency of response to attitude of 5 questions (b) Frequency of response to attitude of 3 questions Figure 2. Response to attitude of the vaccination. (a) Frequency of response to attitude of 5 ques- tions; (b) Frequency of response to attitude of 3 questions. 3.4. ; ( ) q y p 3 4 F f R t P ti 3.4. Frequency of Response to Perception 3.4. Frequency of Response to Perception Perception was assessed by four questions, which were scored as yes, no, do not know, and scaled as 0, for no/do not know and 1 was for a yes response. Scoring scale ranged from 0–4. Responses of participants showed that: 57.0% (n = 228) indicated that after taking the vaccination they should follow guidelines to combat new variants; 56.0% (n = 224) believe that COVID-19 can be eradicated by taking preventive measures instead of vaccination; 79.5% (n = 318) indicated that they prefer to have the vaccination even if their health is compromised by any other ailment; and 60.0% (n = 240) responded that they could not afford vaccination at their own cost if it was not given free of charge by the state. Perception was assessed by four questions, which were scored as yes, no, do not know, and scaled as 0, for no/do not know and 1 was for a yes response. Scoring scale ranged from 0–4. Responses of participants showed that: 57.0% (n = 228) indicated that after taking the vaccination they should follow guidelines to combat new variants; 56.0% (n = 224) believe that COVID-19 can be eradicated by taking preventive measures instead of vaccination; 79.5% (n = 318) indicated that they prefer to have the vaccination even if their health is compromised by any other ailment; and 60.0% (n = 240) responded that they could not afford vaccination at their own cost if it was not given free of charge by the state. Figure 3 shows response to perception of the participants towards vaccination. Medicina 2023, 59, 272 Medicina 2022, 58, x FO 7 of 14 7 of 14 Figure 3. Response to perception of the vaccination. Figure 3. Response to perception of the vaccination. 3 5 Categorization of Participant’s Score and Their Association with Demographics 3.5. Categorization of Participant’s Score and Their Association with Demographics 3 5 Categorization of Participant’s Score and Their Association with Demographics 3.5. Categorization of Participant’s Score and Their Association with Demographics 3.5. Categorization of Participant s Score and Their Association with Demographics Characterization of the participants’ response based on blooms’ cut-off points. Crite- ria of bloom’s cut-off point were 80–100% (good), 60.0–79.0% (fair), and ≤59.0% (poor). Similarly for knowledge, this score was determined from scale 0–6, for attitude score, 0– 16 and for perception score, 0–4. ; ( ) q y p 3 4 F f R t P ti 3.4. Frequency of Response to Perception Responses regarding knowledge, age group of partici- pants and the maximum number of ‘fair knowledge’ was observed in people of the age group of 21–40 years. In the gender category, both male and female participants had an equal level of ‘fair knowledge’. In the marital status group, married people had a high rate of fair knowledge. Students and government employees also had a high rate of fair knowledge. Chi-square analysis was used to find any significant association between de- mographics and knowledge related questions about COVID-19 vaccination. A significant Characterization of the participants’ response based on blooms’ cut-off points. Cri- teria of bloom’s cut-off point were 80–100% (good), 60.0–79.0% (fair), and ≤59.0% (poor). Similarly for knowledge, this score was determined from scale 0–6, for attitude score, 0–16 and for perception score, 0–4. Responses regarding knowledge, age group of participants and the maximum number of ‘fair knowledge’ was observed in people of the age group of 21–40 years. In the gender category, both male and female participants had an equal level of ‘fair knowledge’. In the marital status group, married people had a high rate of fair knowledge. Students and government employees also had a high rate of fair knowledge. Chi-square analysis was used to find any significant association between demographics and knowledge related questions about COVID-19 vaccination. A significant relationship was found between education, employment, and the residence group. relationship was found between education, employment, and the residence group. In responses regarding attitude, participants in the age group of 21–40 years showed a good attitude response. In the gender category, female participants had a high level of ‘good attitude score’. In the marital status group, unmarried people had a high rate of good attitude. Students and urban citizens also had a high rate of good attitude. A signif- icant relationship was found between age, education, marital status, employment, and the p y g p In responses regarding attitude, participants in the age group of 21–40 years showed a good attitude response. In the gender category, female participants had a high level of ‘good attitude score’. In the marital status group, unmarried people had a high rate of good attitude. Students and urban citizens also had a high rate of good attitude. A significant relationship was found between age, education, marital status, employment, and the residence group. residence group. ; ( ) q y p 3 4 F f R t P ti 3.4. Frequency of Response to Perception In responses about perception, participants in the age group of 21–40 years showed a fair attitude response. In the gender category, male participants had a high level of ‘fair perception’. In the marital status group, married people had a high rate of fair perception. Students and urban citizens also had a high rate of fair perception. No significant associ- ation of perception score was noticed with any demographics’ variable. Table 2 summa- In responses about perception, participants in the age group of 21–40 years showed a fair attitude response. In the gender category, male participants had a high level of ‘fair perception’. In the marital status group, married people had a high rate of fair perception. Students and urban citizens also had a high rate of fair perception. No significant association of perception score was noticed with any demographics’ variable. Table 2 summarizes the p value obtained. Medicina 2023, 59, 272 8 of 14 Table 2. Categorization of participants and association of demographics with knowledge, attitude and perception. Knowledge Attitude Perception Variables Good Fair Poor p Value Good Fair Poor p Value Good Fair Poor p Value Age <20 4 25 7 0.347 20 13 3 0.001 8 10 18 0.064 21–40 43 142 29 132 54 28 39 112 63 41–60 26 64 15 35 44 26 22 54 29 Gender >61 10 15 5 10 10 10 8 16 5 Female 32 129 25 103 56 27 0.148 31 96 59 0.077 Male 51 129 30 96 74 40 54 100 55 Marital status Unmarried 40 115 24 0.831 105 49 24 0.005 37 80 62 0.088 Married 44 144 32 94 82 44 49 116 54 Education level high school or below 38 100 34 0.043 66 72 33 0.001 39 82 50 0.577 graduate 27 83 11 67 34 20 28 63 30 postgraduate 19 75 11 66 24 15 19 50 36 Employment status Gov. employee 9 62 10 0.030 38 32 11 0.019 21 40 20 0.615 non Gov. Note: for knowledge score 4.8–6 considered (Good) 3.6–4.7 (Fair) and ≤3.5 (Poor); for attitude score 12.8–16 consid considered good, 2.4–3.16 Fair and ≤2.3 Poor. p value < 0.05 compared within groups. Bold p values showed signifi Note: for knowledge score 4.8–6 considered (Good) 3.6–4.7 (Fair) and ≤3.5 (Poor); for attitude score 12.8–16 considered Good, 9.6–12.7 Fair and ≤9.5 Poor; for perception score 3.2–4 considered good, 2.4–3.16 Fair and ≤2.3 Poor. p value < 0.05 compared within groups. Bold p values showed significant association. 3.6. Analysis of Mean Knowledge, Attitude and Perception To estimate association within groups with mean knowledge, an independent t-test (for two groups) including one for more than two groups and a one-way ANOVA test was performed. The mean count of knowledge was considerably higher among participants aged 21–40 years. Females, unmarried, graduates or below, students, and urban citizens had a higher mean knowledge score. It was found that the mean knowledge score is significantly associated with age, gender, marital status, residence, and employment status. The mean score of attitude was appreciably higher among participants in the age group of 21–40 years. In terms of gender, females had a high mean attitude score. The educational level of participants also plays a role since a higher mean score of attitude was found in postgraduates and similarly in unmarried and non-government participants. Urban residents also showed a higher mean score. Mean attitude is significantly related with age, gender, education level, marital status, residence, and employment status. g g p y The mean score of perception was considerably higher among participants aged 21– 40 years. In terms of gender, females have a high mean perception score. Educational level is a factor contributing to a higher mean score of perception in graduates, while unmarried and student participants also showed a higher mean perception score, as did urban residents. In this survey, the mean attitude is significantly linked with age, gender, education level, marital status, residence, and employment status. Table 3 below shows association within groups with mean knowledge, mean attitude and mean perception score. Table 3. Association within groups with mean knowledge, mean attitude and mean perception score. ; ( ) q y p 3 4 F f R t P ti 3.4. Frequency of Response to Perception employee 13 53 9 42 22 11 13 39 23 self employed 9 17 4 7 15 8 10 13 7 Student 27 63 17 64 25 17 19 55 33 Retired 14 15 7 12 14 10 10 17 8 Unemployed 12 47 8 34 22 11 13 30 24 Residence Urban 48 187 44 0.015 149 85 44 0.051 58 141 80 0.755 Rural 35 69 13 47 46 24 27 54 35 Note: for knowledge score 4.8–6 considered (Good) 3.6–4.7 (Fair) and ≤3.5 (Poor); for attitude score 12.8–16 considered Good, 9.6–12.7 Fair and ≤9.5 Poor; for perception score 3.2–4 considered good, 2.4–3.16 Fair and ≤2.3 Poor. p value < 0.05 compared within groups. Bold p values showed significant association. gorization of participants and association of demographics with knowledge, attitude and perception. Medicina 2023, 59, 272 9 of 14 3.6. Analysis of Mean Knowledge, Attitude and Perception 3.6. Analysis of Mean Knowledge, Attitude and Perception Mean Knowledge Mean Attitude Mean Perception Variables Mean (S.D) p Value Mean (S.D) p Value Mean (S.D) p Value Age 0.5602 (0.165) 0.5964 (0.19568) 0.3759 (0.26572) 0.1944 (0.19615) 0.009 1.5556 (0.28730) 1.5736 (0.37016) 1.4029 (0.34624) 1.3375 (0.39000) 0.001 0.6111 (0.24960) 0.6752 (0.21860) 0.4762 (0.29114) 0.3750 (0.29906) 0.001 <20 21–40 41–60 >61 Gender 0.5658 (0.20926) 0.4525 (0.26746) 0.001 1.5390 (0.36552) 1.4705 (0.37266) 0.066 0.6452 (0.23052) 0.5226 (0.30705) 0.017 Female Male Marital Status 0.6134 (0.19448) 0.4188 (0.25468) 0.012 1.5475(0.37851) 1.4662(0.36106) 0.029 0.6508 (0.23912) 0.5239 (0.29792) 0.002 Unmarried Married Education Level 0.3777 (0.25744) 0.6074 (0.19467) 0.5997 (0.19107) 0.001 1.4523 (0.33256) 1.5289 (0.38587) 1.5560 (0.40541) 0.051 0.4753 (0.29452) 0.6426(0.26581) 0.6810 (0.20655) 0.001 High school or below Graduate Postgraduate Employment Status 0.5251 (0.20190) 0.5431 (0.23216) 0.2889 (0.25496) 0.6184(0.19018) 0.2269 (0.23622) 0.5075 (0.24521) 0.001 1.5231 (0.29981) 1.5724 (0.33364) 1.2750 (0.40921) 1.5339 (0.39624) 1.3819 (0.31756) 1.5037 (0.41342) 0.002 0.5494 (0.30726) 0.5967 (0.25959) 0.5250 (0.33701) 0.6752 (0.21504) 0.3750 (0.29580) 0.5821 (0.26610) 0.001 Gov. employee Non Gov. employee Self employed Student Retired Unemployed Residence 0.5446 (0.21737) 0.4074 (0.29152) 0.019 1.5302 (0.35036) 1.4306 (0.41015) 0.015 0.6246 (0.26132) 0.4722 (0.29503) 0.026 Urban Rural Note: S.D is standard deviation. Statistics: one way ANOVA and independent t test; p value < 0.05 compared within groups. Bold p values showed significant association. Table 3. Association within groups with mean knowledge, mean attitude and mean perception score. Medicina 2023, 59, 272 10 of 14 10 of 14 3.7. Factors Affecting Knowledge, Attitude and Perception Response on the Use of Vaccine A multiple linear regression model was used to analyze the impact of an independent variable over a dependent variable, as illustrated in Table 4. Age, education, residence, and employment status influenced the knowledge score to a considerable extent. Gender and marital status had no significant impact on the knowledge score. Correlation analyses shows that the relationship between the dependent and independent variable is a reliable factor for further analysis. Perception score was significantly influenced by age, education, and residence. Table 4. Analysis of factors affecting knowledge, attitude, and perception score. 3.6. Analysis of Mean Knowledge, Attitude and Perception Independent Variable Knowledge Attitude Perception R Square 0.316 R Square 0.063 R Square 0.224 Adjusted R Square 0.293 Adjusted R Square 0.031 Adjusted R Square 0.198 Durbin Watson 1.657 Durbin Watson 1.938 Durbin Watson 1.718 B SE p-Value B SE p-Value B SE p-Value (Constant) 0.622 0.057 0.000 1.641 0.090 0.000 0.678 0.066 0.000 Age −0.070 0.028 0.013 −0.073 0.045 0.106 −0.069 0.033 0.036 Gender 0.007 0.040 0.869 0.024 0.063 0.704 −0.033 0.046 0.471 Marital status 0.076 0.047 0.110 −0.053 0.076 0.483 0.054 0.055 0.329 Education level 0.077 0.025 0.002 0.013 0.040 0.751 0.076 0.029 0.009 Employment status −0.028 0.010 0.006 −0.015 0.016 0.349 −0.021 0.012 0.067 Residence −0.075 0.034 0.030 −0.034 0.055 0.533 −0.140 0.040 0.001 Note: B = unstandardized regression coefficient; SE = Standard error; p value < 0.05 considered significant. Bold p values showed significant association. Statistics: Multiple linear regression model; p value < 0.05 compared within groups. Table 4. Analysis of factors affecting knowledge, attitude, and perception score. Note: B = unstandardized regression coefficient; SE = Standard error; p value < 0.05 considered significant. Bold p values showed significant association. Statistics: Multiple linear regression model; p value < 0.05 compared within groups. 4. Discussion In order to overcome the aftermath of the COVID-19 pandemic, the implementation of COVID-19 vaccination is the best if not the ideal solution. After an extensive development phase and positive responses of clinical trials, various countries approved specific vaccines for further implementation. Although various campaigns have been implemented to increase knowledge about vaccination and previous studies also suggests that COVID- 19 vaccines are safe and effective in general, based on the billions of doses administered worldwide and the rare incidence of adverse events only in at-risk group [37]. However, due to the newness of this disease, it poses a serious question for policy-makers regarding the knowledge, attitude, and perceptions of the general population about receiving the COVID- 19 vaccination. The present survey has been conducted to assess knowledge, attitude, and perceptions of participants including large demographics factors that influence the knowledge and attitude of the general population [38]. This knowledge-based survey suggest that the people of Pakistan that participated in this study had an average knowledge (50.4%) about the vaccine, its side effects, allergic reactions, and its effect on autoimmune diseases. Knowledge was considerably linked with education, employment status, and residence. This finding is in contrast with the knowl- edge, attitude, and perception survey conducted in Bangladesh, where knowledge was significantly associated with education, family type, and monthly income of a family [38]. The findings of our survey suggest that the mean knowledge score was found to be higher for female participants, in respondents of the age group 21–40, among graduates, and in unmarried participants. These findings concur with two previous surveys conducted in China and the USA. Data from this survey also indicate that gender and education level Medicina 2023, 59, 272 11 of 14 11 of 14 could have a constructive impact on the knowledge field of participants [39,40]. In our survey, 76.2% of participants had a lack of knowledge regarding the safety of the COVID-19 vaccination in pregnant women. These findings stress the need to convey effective and updated information for the general population through various social media platforms. Regarding the attitude domain of this study, a mean attitude score is more associated with females than males. This finding is in line with the results of the studies conducted in Indonesia and Bangladesh [41,42]. 4. Discussion We believe this result can be of significant value by appealing to women with a domestic level of education and an encouragement for COVID-19 vaccination could strongly suggest the way to a drastic enhancement in the vaccination program. The findings of a high level of a positive attitude of participants towards the preventive measure of vaccination is also reported globally [42]. Our findings show that 64.3% of the participants were willing to take the COVID-19 vaccination without any hesitation, and 75.3% advised their family, friends, and relatives to also take the COVID-19 vaccination. Findings from our study illustrate the wide scale of variation among countries. A study conducted in France during the pandemic shows that 77% of their participants would agree to take the vaccination [43]. While comparing attitude globally in terms of willingness to take the vaccine, studies show that a high percentage of positive attitude responses come from Panama (87.44%), a lower reaction was from Russia (51.34%), Australia had the highest response (92.88%), while the very lowest response was observed in Egypt (43.55%) for taking the COVID-19 vaccination [44]. An average number of participants (51.8%) in our study agreed that the vaccine is safe. This limited knowledge regarding safety of vaccination may be due to rumors and misinformation related to safety issues of the vaccine. Since the pandemic is generally accepted to have started in December 2019, there was only limited knowledge about the disease, along with rumors and misinformation that affected its perception globally [45]. g p p g y In the perception domain, 57% of participants believe that COVID-19 vaccination had side effects. This apprehension may be due to misinformation regarding fatal and adverse events associated with the COVID-19 vaccine [46,47]. Overall, in our study, female participants had a better ranking of knowledge, at- titude, and perception, as compared to males, which is in agreement with findings of prior studies [48]. Possible reasons identified for this were education and socio-economic factors [49,50]. Equal participation by both genders is important for any social survey. This is because both males and females are equally important for forming an opinion about any critical social issues, such as the COVID-19 vaccination. However, in our study, female participa- tion was found to be less than males, which agrees with a previous knowledge, attitude, and perception survey [51]. 4. Discussion These findings suggest that more focused research needs to be conducted to determine the possible barriers that women might be facing in participating in such responses. p In this survey, graduates and postgraduates illustrated high scores towards knowledge, attitude, and perception. This finding suggests that education plays an important role to overcome such pandemics since educated citizens had a greater tendency to analyze the critical situations and consequently behave positively. Various research studies have been conducted to initiate effective strategies in order to improve the vaccination rate. These studies show that information alone has a limited impact on enhancing the vaccination rate. Acceptance and a willingness of vaccination is still an unparalleled challenge. Data of this survey could strengthen the efforts of health authorities to achieve their targets of high vaccination coverage through effective communication and updated information. Limitations This survey was conducted over a short time period with incompetence to reach people residing in far-off, remote locations with no access to the Internet, and therefore the findings obtained in this survey might not express the perspective of the whole general Medicina 2023, 59, 272 12 of 14 12 of 14 population, and the sample was not generalized to a meaningful population. The general population who do not have Internet access and were not proficient in working with online platforms were difficult to connect with. The study used a virtual self-reporting system that may be exposed to social acceptability and memory biases. There would be a response biasness, too, about being judged on knowledge or on financial situations, that also resulted in low responses being one of the drawbacks of online survey. 5. Conclusions Until the development of vaccines, the COVID-19 pandemic was a major global threat. Our survey reflects a poor knowledge (50.6%), fair attitude (75.1%), and poor perception (58.1%) towards vaccination. These findings suggest that more educational campaigns and the advertisement of the correct information status could contribute fairly to eradicating the pandemic. Guiding principle makers can take preliminary steps to ensure the distribution of positive information about the attitudes and perceptions towards COVID-19 vaccinations in order to decrease the vaccine timidity and to increase the vaccination rate. However, research should be performed on participants not included in this study, such as immigrants and the elderly, who do not have access to social media and technology. Author Contributions: Conceptualization: A.B. and A.K.; data curation: A.K. and A.M.; formal analysis: S.M.; investigation: A.B. and A.K.; methodology: A.B. and A.K.; project administration: A.B.; resources: A.M.; supervision: A.K.; visualization: A.M. and Y.H.K.; writing—original draft: A.B.; writing—review and editing: A.K., S.A., T.H.M., and I.R.G. All authors have read and agreed to the published version of the manuscript. Funding: This research received no external funding. Funding: This research received no external funding. Institutional Review Board Statement: The study was conducted after ethical approval by the Institutional Review Board (or Ethics Committee) of RAWALPINDI MEDICAL UNIVERSITY (ref. no. 64/IREF/RMU/2021 and date of approval was 23 April 2021). Informed Consent Statement: Purpose of this survey was clearly explained and written informed consent has been obtained from the participants to publish this paper. Acknowledgments: We acknowledge all the participants who consented to be a part of this re- search project. Conflicts of Interest: The authors declare no conflict of interest. Conflicts of Interest: The authors declare no conflict of interest. References 1. Lim, Y.; Ng, Y.; Tam, J.; Liu, D. Human Coronaviruses: A Review of Virus–Host Interactions. Diseases 2016, 4, 26. [CrossRef] [PubMed] 2. Abid, K.; Bari, Y.A.; Younas, M.; Tahir Javaid, S.; Imran, A. Progress of COVID-19 Epidemic in Pakistan. Asia-Pac. J. Public Health 2020, 32, 154–156. [CrossRef] [PubMed] 3. Kim, E.S.; Chin, B.S.; Kang, C.K.; Kim, N.J.; Kang, Y.M.; Choi, J.P.; Oh, D.H.; Kim, J.-H.; Koh, B.; Kim, S.E.; et al. Clinical course and outcomes of patients with severe acute respiratory syndrome coronavirus 2 infection: A preliminary report of the first 28 patients from the korean cohort study on COVID-19. J. Korean Med. Sci. 2020, 35, e142. [CrossRef] [PubMed] 4. Lei, S.; Jiang, F.; Su, W.; Chen, C.; Chen, J.; Mei, W.; Zhan, L.-Y.; Jia, Y.; Zhang, L.; Liu, D.; et al. Clinical characteristics and outcomes of patients undergoing surgeries during the incubation period of COVID-19 infection. EClinicalMedicine 2020, 21, 100331. [CrossRef] [PubMed] 5. Xie, J.; Tong, Z.; Guan, X.; Du, B.; Qiu, H. Clinical Characteristics of Patients Who Died of Coronavirus Disease 2019 in China. JAMA Netw Open 2020, 3, e205619. [CrossRef] 5. Xie, J.; Tong, Z.; Guan, X.; Du, B.; Qiu, H. Clinical Characteristics of Patients Who Died of Coronavirus Disease 2019 in China. JAMA Netw Open 2020, 3, e205619. [CrossRef] 6. Gandhi, R.T.; Lynch, J.B.; del Rio, C. Mild or Moderate Covid-19. N. Engl. J. Med. 2020, 383, 1757–1766. [CrossRef] 7. Fu, L.; Wang, B.; Yuan, T.; Chen, X.; Ao, Y.; Fitzpatrick, T.; Li, P.; Zhou, Y.; Lin, Y.-F.; Duan, Q.; et al. Clinical characteristics of coronavirus disease 2019 (COVID-19) in China: A systematic review and meta-analysis. J. Infect. 2020, 80, 656–665. [CrossRef] 8. Helmy, Y.A.; Fawzy, M.; Elaswad, A.; Sobieh, A.; Kenney, S.P.; Shehata, A.A. The COVID-19 pandemic: A comprehensive review of taxonomy, genetics, epidemiology, diagnosis, treatment, and control. J. Clin. Med. 2020, 9, 1225. [CrossRef] 7. Fu, L.; Wang, B.; Yuan, T.; Chen, X.; Ao, Y.; Fitzpatrick, T.; Li, P.; Zhou, Y.; Lin, Y.-F.; Duan, Q.; et al. Clinical characteristics of coronavirus disease 2019 (COVID-19) in China: A systematic review and meta-analysis. J. Infect. 2020, 80, 656–665. [CrossRef] 8. Helmy, Y.A.; Fawzy, M.; Elaswad, A.; Sobieh, A.; Kenney, S.P.; Shehata, A.A. The COVID-19 pandemic: A comprehensive review of taxonomy, genetics, epidemiology, diagnosis, treatment, and control. J. Clin. Med. 2020, 9, 1225. [CrossRef] y y f 8. 9. Tang, D.; Tou, J.; Wang, J.; Chen, Q.; Wang, W.; Huang, J.; Zhao, H.; Wei, J.; Xu, Z.; Zhao, D.; et al. Prevention and control strategies for emergency, limited-term, and elective operations in pediatric surgery during the epidemic period of COVID-19. World J. Pediatr. Surg. 2020, 3, e000122. [CrossRef] References Helmy, Y.A.; Fawzy, M.; Elaswad, A.; Sobieh, A.; Kenney, S.P.; Shehata, A.A. The COVID-19 pandemic: A comprehensive review of taxonomy, genetics, epidemiology, diagnosis, treatment, and control. J. Clin. Med. 2020, 9, 1225. [CrossRef] y g p gy g J [ ] 9. Tang, D.; Tou, J.; Wang, J.; Chen, Q.; Wang, W.; Huang, J.; Zhao, H.; Wei, J.; Xu, Z.; Zhao, D.; et al. Prevention and control strategies for emergency, limited-term, and elective operations in pediatric surgery during the epidemic period of COVID-19. World J. Pediatr. Surg. 2020, 3, e000122. [CrossRef] 13 of 14 13 of 14 Medicina 2023, 59, 272 10. Chan, J.F.-W.; Yuan, S.; Kok, K.-H.; To, K.K.-W.; Chu, H.; Yang, J.; Xing, F.; Liu, J.; Yip, C.C.-Y.; Poon, R.W.-S.; et al. A familial cluster of pneumonia associated with the 2019 novel coronavirus indicating person to person transmission: A study of a family cluster. Lancet 2020, 395, 514–523. [CrossRef] 11. Chirwa, G.C. “Who knows more, and why?” Explaining socioeconomic-related inequality in know Sci. Afr. 2020, 7, e00213. [CrossRef] knows more, and why?” Explaining socioeconomic-related inequality in knowledge about HIV in Malawi 213. [CrossRef] f 12. UNICEF. Another 1.2 Million Doses of COVID-19 Vaccine Reach Pakistan through COVAX. 2021. Available online: https://www. unicef.org/pakistan/press-releases/another-12-million-doses-covid-19-vaccine-reach-pakistan-through-covax (accessed on 29 July 2021). y 13. Farooq, U.; Pakistan to Receive 13 Million Doses of Pfizer Vaccine—Minister. Reuters. Sec. Asia Pacific. 2021. Available online: https://www.reuters.com/world/asia-pacific/pakistan-receive-13-mln-doses-pfizer-vaccine-minister-2021-06-22/ (accessed on 31 July 2021). J y ) 14. Hussain, S.; Pakistan Set to Procure 30 Million Doses of Coronavirus Vaccine. Yahoo! News. 2021. Available online: https: //in.news.yahoo.com/pakistan-set-procure-30-million-120755420.html (accessed on 31 July 2021). 15. Widakuswara, P. US Ships Moderna Vaccine to Pakistan Amid Delta Variant Surge | Voice of America—English. Voice of America. 2021. Available online: https://www.voanews.com/covid-19-pandemic/us-ships-moderna-vaccine-pakistan-amid- delta-variant-surge (accessed on 31 July 2021). g ( J y ) 16. Shahzad, A.; Pakistan Commits $1.1 Bln for COVID Vaccine to Cover Eligible Population. Reuters. Sec. Asia Pacific. 2021. Available online: https://www.reuters.com/world/asia-pacific/pakistan-administers-10-mln-covid-vaccine-doses-eyes-70 -mln-target-2021-06-09/ (accessed on 31 July 2021). g / ( J y ) 17. Government of Pakistan. Covid-19 Situation. 2021. Available online: https://covid.gov.pk/ (accessed on 31 July 2021). g ( y ) 17. Government of Pakistan. Covid-19 Situation. 2021. Available online: https://covid.gov.pk/ (accessed p g p 18. Gavi the Vaccine Alliance. Pakistan Progressing on Immunization Efforts. 2016. Available online: https media-room/pakistan-progressing-immunisation-efforts (accessed on 31 July 2021). p p g g y 19. References Khan, M.S.; Improving the Covid-19 Vaccination Rate in Pakistan—A Multipronged Policy Approach. Front. Public Health 2021. Available online: https://www.frontiersin.org/article/10.3389/fpubh.2021.729102 (accessed on 29 July 2021). 20. Reiter, P.L.; Pennell, M.L.; Katz, M.L. Acceptability of a COVID-19 vaccine among adults in the United States: How many people would get vaccinated? Vaccine 2020, 38, 6500–6507. [CrossRef] [PubMed] 21. Akbulut, S.; Gokce, A.; Boz, G.; Saritas, H.; Unsal, S.; Ozer, A.; Akbulut, M.S.; Colak, C. Evaluation of Vaccine Hesitancy and Anxiety Levels among Hospital Cleaning Staff and Caregivers during COVID-19 Pandemic. Vaccines 2022, 10, 1426. [CrossRef] [PubMed] 22. ˙Ikiı¸sık, H.; Akif Sezerol, M.; Ta¸sçı, Y.; Maral, I. COVID-19 vaccine hesitancy: A community-based research in Turkey. Int. J. Clin. Pract. 2021, 75, e14336. [CrossRef] [PubMed] 23. Khamis, F.; Badahdah, A.; Al Mahyijari, N.; Al Lawati, F.; Al Noamani, J.; Al Salmi, I.; Al Bahrani, M. Attitudes Towards COVID-19 Vaccine: A Survey of Health Care Workers in Oman. J. Epidemiol. Glob. Health 2022, 12, 1–6. [CrossRef] 24. Malik, A.A.; McFadden, S.A.M.; Elharake, J.; Omer, S.B. Determinants of COVID-19 vaccine acceptance in the US. EClinicalMedicine 2020, 26, 100495. [CrossRef] 25. Yakut, S.; Karagülle, B.; Atçalı, T.; Öztürk, Y.; Açık, M.N.; Çetinkaya, B. Knowledge, attitudes, practices and some characteristic features of people recovered from COVID-19 in Turkey. Medicina 2021, 57, 431. [CrossRef] 26. Al-Marshoudi, S.; Al-Balushi, H.; Al-Wahaibi, A.; Al-Khalili, S.; Al-Maani, A.; Al-Farsi, N.; Al-Jahwari, A.; Al-Habsi, Z.; Al-Shaibi, M.; Al-Msharfi, M.; et al. Knowledge, attitudes, and practices (Kap) toward the covid-19 vaccine in oman: A pre-campaign cross-sectional study. Vaccines 2021, 9, 602. [CrossRef] 27. Neumann-Böhme, S.; Varghese, N.E.; Sabat, I.; Barros, P.P.; Brouwer, W.; van Exel, J.; Stargardt, T. Once we have it, will we use it? A European survey on willingness to be vaccinated against COVID-19. Eur. J. Health Econ. 2020, 21, 977–982. [CrossRef] 28. Akhu-Zaheya, L.M.; Jagbir, M.T.; Othman, A.; Ahram, M. Media use for seeking health/cancer-related information: Findings from knowledge, attitudes and practices towards cancer prevention and care survey in Jordan. Int. J. Nurs. Pract. 2014, 20, 608–615. [CrossRef] 29. Gallè, F.; Sabella, E.A.; Roma, P.; Da Molin, G.; Da Molin, G.; Diella, G.; Montagna, M.T.; Ferracuti, S.; Liguori, G.; Orsi, G.B.; et al. Acceptance of covid-19 vaccination in the elderly: A cross-sectional study in Southern Italy. Vaccines 2021, 9, 1–12. [CrossRef] [PubMed] [ ] 30. Lin, Y.; Hu, Z.; Zhao, Q.; Alias, H.; Danaee, M.; Wong, L.P. References [CrossRef] Ahttp://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=PMC9527088 (accessed on 31 July 202 Islam, M.; Siddique, A.B.; Akter, R.; Tasnim, R.; Safaet, M.; Sujan, H.; Ward, P.R.; Sikder, M.T. Knowledge 39. Saiful Islam, M.; Siddique, A.B.; Akter, R.; Tasnim, R.; Safaet, M.; Sujan, H.; Ward, P.R.; Sikder, M.T. Knowledge, attitudes and perceptions towards COVID-19 vaccinations: A cross-sectional community survey in Bangladesh. BMC Public Health 2021, 21, 1–11. [CrossRef] 40. Fu, C.; Wei, Z.; Pei, S.; Li, S.; Sun, X.; Liu, P. Acceptance and preference for COVID-19 vaccination in health-care workers (HCWs). medRxiv 2020, 548, 2962. 41. Larson, H.J.; Smith, D.M.D.; Paterson, P.; Cumming, M.; Eckersberger, E.; Freifeld, C.C.; Ghinai, I.; Jarrett, C.; Paushter, L.; Brownstein, J.S.; et al. Measuring vaccine confidence: Analysis of data obtained by a media surveillance system used to analyse public concerns about vaccines. Lancet Infect. Dis. 2013, 13, 606–613. [CrossRef] [PubMed] p f 42. Harapan, H.; Anwar, S.; Bustaman, A.; Radiansyah, A.; Angraini, P.; Fasli, R.; Salwiyadi, S.; Bastian, R.A.; Oktiviyari, A.; Akmal, I.; et al. Modifiable determinants of attitude towards dengue vaccination among healthy inhabitants of Aceh, Indonesia: Findings from a community-based survey. Asian Pac. J. Trop. Med. 2016, 9, 1115–1122. Available online: https://www.sciencedirect.com/ science/article/pii/S1995764516303686 (accessed on 29 July 2021). [CrossRef] [PubMed] 43. Ferdous, M.Z.; Islam, M.S.; Sikder, M.T.; Mosaddek, A.S.M.; Zegarra-Valdivia, J.A.; Gozal, D. Knowledge, attitude, and practice regarding COVID-19 outbreak in Bangladesh: An online-based cross-sectional study. PLoS ONE 2020, 15, e0239254. [CrossRef] 44. Detoc, M.; Bruel, S.; Frappe, P.; Tardy, B.; Botelho-Nevers, E.; Gagneux-Brunon, A. Intention to participate in a COVID-19 vaccine clinical trial and to get vaccinated against COVID-19 in France during the pandemic. Vaccine 2020, 38, 7002–7006. [CrossRef] [PubMed] 43. Ferdous, M.Z.; Islam, M.S.; Sikder, M.T.; Mosaddek, A.S.M.; Zegarra-Valdivia, J.A.; Gozal, D. Knowledge, attitude, and practice regarding COVID-19 outbreak in Bangladesh: An online-based cross-sectional study. PLoS ONE 2020, 15, e0239254. [CrossRef] regarding COVID-19 outbreak in Bangladesh: An online-based cross-sectional study. PLoS ONE 2020, 15, e0239254. [CrossRef] 44. Detoc, M.; Bruel, S.; Frappe, P.; Tardy, B.; Botelho-Nevers, E.; Gagneux-Brunon, A. Intention to participate in a COVID-19 vaccine clinical trial and to get vaccinated against COVID-19 in France during the pandemic. Vaccine 2020, 38, 7002–7006. [CrossRef] [PubMed] 45. Mannan, K.A.; Farhana, K.M. Knowledge, Attitude and Acceptance of a COVID-19 Vaccine: A Global Cross-Sectional Study. SSRN Electron. J. 2021, 6, 1–23. [CrossRef] 46. Lazarus, J.V.; Ratzan, S.C.; Palayew, A.; Gostin, L.O.; Larson, H.J.; Rabin, K.; Kimball, S.; El-Mohandes, A. Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content. References Understanding COVID-19 vaccine demand and hesitancy: A nationwide online survey in China. PLoS Negl. Trop. Dis. 2020, 14, e0008961. [CrossRef] [PubMed] 31. Palamenghi, L.; Barello, S.; Boccia, S.; Graffigna, G. Mistrust in biomedical research and vaccine hesitancy: The forefront challenge in the battle against COVID-19 in Italy. Eur. J. Epidemiol. 2020, 35, 785–788. [CrossRef] [PubMed] 31. Palamenghi, L.; Barello, S.; Boccia, S.; Graffigna, G. Mistrust in biomedical research and vaccine hesitancy: The forefront challenge in the battle against COVID-19 in Italy. Eur. J. Epidemiol. 2020, 35, 785–788. [CrossRef] [PubMed] 32. MacDonald, N.E.; Smith, J.; Appleton, M. Risk perception, risk management and safety assessment: increase public confidence in their vaccine system? Biologicals 2012, 40, 384–388. [CrossRef] onald, N.E.; Smith, J.; Appleton, M. Risk perception, risk management and safety assessment: What can go se public confidence in their vaccine system? Biologicals 2012, 40, 384–388. [CrossRef] p y g 33. Papagiannis, D.; Malli, F.; Raptis, D.G.; Papathanasiou, I.V. Assessment of knowledge, attitudes, and practices towards new coronavirus (SARS-CoV-2) of health care professionals in Greece before the outbreak period. Int. J. Environ. Res. Public Health 2020, 17, 4925. [CrossRef] 34. Harkness, J.A.; Schoua-Glusberg, A. Questionnaires in Translation. ZUMA-Nachr. Spez. 1998, 3, 87–126. Available online: http://isites.harvard.edu/fs/docs/icb.topic506406.files/znspez3_04_Harkness_Glusberg.pdf (accessed on 22 July 2021). 14 of 14 Medicina 2023, 59, 272 14 of 14 35. A Guide To Developing Knowledge, Attitude and Practice Surveys; WHO: Geneva, Switzerland, 2008. 36. Akalu, Y.; Ayelign, B.; Molla, M.D. Knowledge, attitude and practice towards covid-19 among chronic disease patients at addis zemen hospital, Northwest Ethiopia. Infect. Drug Resist. 2020, 13, 1949–1960. [CrossRef] , y g , , g , p g zemen hospital, Northwest Ethiopia. Infect. Drug Resist. 2020, 13, 1949–1960. [CrossRef] p p 37. Policy, H. The Knowledge and Attitude of the Community from the Aseer Region, Saudi Arabia, T Precautionary Measures Against the Disease. Risk Manag. Healthc. Policy 2020, 13, 1825. y, H. The Knowledge and Attitude of the Community from the Aseer Region, Saudi Arabia, Toward COVID utionary Measures Against the Disease. Risk Manag. Healthc. Policy 2020, 13, 1825. 38. Goyal, L.; Zapata, M.; Ajmera, K.; Chaurasia, P.; Pandit, R.; Pandit, T. A Hitchhiker’s Guide to Worldwide COVID-19 Vaccinations: A Detailed Review of Monovalent and Bivalent Vaccine Schedules, COVID-19 Vaccine Side Effects, and Effectiveness Against Omicron and Delta Variants. Cureus 2022, 14, e29837. Available online: http://www.ncbi.nlm.nih.gov/pubmed/36204257%0 Ahttp://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=PMC9527088 (accessed on 31 July 2021). References A global survey of potential acceptance of a COVID-19 vaccine. Nat. Med. 2021, 27, 225–228. [CrossRef] 47. Lombardi, A.; Bozzi, G.; Ungaro, R.; Villa, S.; Castelli, V.; Mangioni, D.; Muscatello, A.; Gori, A.; Bandera, A. Mini Review Immunological Consequences of Immunization With COVID-19 mRNA Vaccines: Preliminary Results. Front. Immunol. 2021, 12, 1–11. [CrossRef] 48. Voysey, M.; Clemens, S.A.C.; Madhi, S.A.; Weckx, L.Y.; Folegatti, P.M.; Aley, P.K.; Angus, B.; Baillie, V.L.; Barnabas, S.L.; Bhorat, Q.E.; et al. Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: An interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK. Lancet 2021, 397, 99–111. [CrossRef] 49. Al-Zalfawi, S.M.; Rabbani, S.I.; Asdaq, S.M.B.; Alamri, A.S.; Alsanie, W.F.; Alhomrani, M.; Mohzari, Y.; Alrashed, A.A.; AlRifdah, A.H.; Almagrabe, T. Public knowledge, attitude, and perception towards COVID-19 vaccination in Saudi Arabia. Int. J. Environ. Res. Public Health 2021, 18, 10081. [CrossRef] 50. Green, M.S.; Abdullah, R.; Vered, S.; Nitzan, D. A study of ethnic, gender and educational differences in attitudes toward COVID-19 vaccines in Israel—Implications for vaccination implementation policies. Isr. J. Health Policy Res. 2021, 10, 1–12. [CrossRef] [PubMed] 51. Jabal, K.A.; Ben-Amram, H.; Beiruti, K.; Batheesh, Y.; Sussan, C.; Zarka, S.; Edelstein, M. Impact of age, ethnicity, sex and prior infection status on immunogenicity following a single dose of the BNT162b2 MRNA COVID-19 vaccine: Real-world evidence from healthcare workers, Israel, December 2020 to January 2021. Eurosurveillance 2021, 26, 2100096. [CrossRef] [PubMed] Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.
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Modelling the emergence of rodent filial huddling from physiological huddling
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Subject Category: Biology (whole organism) Subject Category: Biology (whole organism) on November 22, 2017 http://rsos.royalsocietypublishing.org/ Downloaded from on November 22, 2017 http://rsos.royalsocietypublishing.org/ Downloaded from rsos.royalsocietypublishing.org Research Cite this article: Wilson SP. 2017 Modelling the emergence of rodent filial huddling from physiological huddling. R.Soc.opensci. 4: 170885. http://dx.doi.org/10.1098/rsos.170885 SPW, 0000-0001-8125-5133 SPW, 0000-0001-8125-5133 SPW, 0000-0001-8125-5133 Huddling behaviour in neonatal rodents reduces the metabolic costs of physiological thermoregulation. However, animals continue to huddle into adulthood, at ambient temperatures where they are able to sustain a basal metabolism in isolation from the huddle. This ‘filial huddling’ in older animals is known to be guided by olfactory rather than thermal cues. The present study aimed to test whether thermally rewarding contacts between young mice, experienced when thermogenesis in brown adipose fat tissue (BAT) is highest, could give rise to olfactory preferences that persist as filial huddling interactions in adults. To this end, a simple model was constructed to fit existing data on the development of mouse thermal physiology and behaviour. The form of the model that emerged yields a remarkable explanation for filial huddling; associative learning maintains huddling into adulthood via processes that reduce thermodynamic entropy from BAT metabolism and increase information about social ordering among littermates. Received: 11 July 2017 Accepted: 24 October 2017 Received: 11 July 2017 Accepted: 24 October 2017 Research 1Department of Psychology, and 2Sheffield Robotics, The University of Sheffield, Sheffield, UK 1Department of Psychology, and 2Sheffield Robotics, The University of Sheffield, Sheffield, UK Cite this article: Wilson SP. 2017 Modelling the emergence of rodent filial huddling from physiological huddling. R.Soc.opensci. 4: 170885. rsos.royalsocietypublishing.org R.Soc. opensci. 4: 170885 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . p g The huddling behaviour of laboratory rodents, in particular rats and mice, has emerged as a model system for the study of social thermoregulation. This is due to their prevalence as laboratory species, and to the precision with which the thermal physiology of these species has been investigated [12,13]. A number of agent-based computer models [5,8,14–20] have been formulated to describe how rodent huddling behaviours at the level of the group emerge from simple rules of interaction between individuals [5,6,21,22]. The individual behaviour from which rodent huddling emerges has been described formally as ‘homeothermotaxis’; turning in the direction that brings the body temperature closer to a preferred temperature [18,19]. As such, individuals act like the magnetic spins in an Ising model, or the particles in a Vicsek model from statistical physics, attracted or repelled by the relative body temperatures of their littermates [20]. These thermodynamic models have been used to explain a phase transition in mouse huddling behaviours, from aggregation in cold environments to dispersion at warmer temperatures [5,18], and by analogy with particle systems they generate new predictions, such as a temperature- dependent peak in ‘pup flow’, where animals cycle between the cold huddle periphery and its warm core [6,20]. Central to thermodynamic descriptions of huddling is a role for brown adipose fat tissue (BAT), which evolved as the organ of thermogenesis in early mammals [23,24], and has been shown to be a requirement for the emergence of huddling [25–28]. Individual differences in early huddling can be explained in terms of individual differences in thermal physiology, for example sex differences in rat huddling can be understood by considering females, who are born with more BAT, as heat sources and males as heat sinks [29]. Syrian golden hamsters, which start to produce heat by BAT thermogenesis relatively late in postnatal development, will initiate huddling behaviours when introduced into groups of age-matched rats, who are generating heat via BAT at this age [26,27]. In turn, early individual differences in huddling behaviours have been shown to predict metrics of adult social behaviour. For example, rabbit pups that tend to occupy peripheral versus central positions in the huddle during the first postnatal week are more likely to jump a gap to attend to the cries of a distressed littermate when tested as adults ([30]; see also [31–33]). 1. Introduction Social thermoregulation has been described in social insects, reptiles, birds and mammals, including humans. For example, honeybee swarms cluster to form structures whose surface density varies with the environment temperature, maintaining the porous core at thermal homeostasis [1]. Common garter snakes in Canada have been found to hibernate in dens comprising 8000 animals for up to a third of the year during winter [2]. Emperor penguins aggregate at a density of up to 10 birds per square metre, adapting the overall shape of the huddle to weather cold winds [3]. Bats huddle to compensate for poor insulation in forest roosting sites, and huddling is important for the initiation and maintenance of group cohesion during collective roost-switching behaviours [4]. Other rodents, including mice [5], rats [6], rabbits [7] and degus [8], huddle to insulate from the Author for correspondence: Stuart P. Wilson e-mail: s.p.wilson@sheffield.ac.uk Electronic supplementary material is available online at https://doi.org/10.6084/m9. figshare.c.3928318 Electronic supplementary material is available online at https://doi.org/10.6084/m9. figshare.c.3928318 2017 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited. 2017 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited. on November 22, 2017 http://rsos.royalsocietypublishing.org/ Downloaded from on November 22, 2017 http://rsos.royalsocietypublishing.org/ Downloaded from cold, by collectively reducing the exposed surface-area-to-volume ratio of the group [9,10]. And social thermoregulation in primates (bamboo lemurs) has recently been shown to be more important for temperature homeostasis than the choice of resting site [11]. cold, by collectively reducing the exposed surface-area-to-volume ratio of the group [9,10]. And social thermoregulation in primates (bamboo lemurs) has recently been shown to be more important for temperature homeostasis than the choice of resting site [11]. 2 2. Models A Monte Carlo algorithm has recently been shown to capture the statistics of huddling behaviour [20], i.e. the distribution of groups of pups in contact, as predicted by more elaborate models of the underlying physical interactions between littermates (see [18,19,47]). The idea is to iteratively reconfigure the distribution of pups between groups by choosing pairs of pups at random from the litter and either joining together the groups to which they belong, or isolating one from its group. The decision between these two alternatives is made by comparing a randomly generated number each time to a value representing the probability that those two pups will remain in contact. If the random number is less than the probability of remaining in contact, then the groups to which the two pups belong are joined together to form a larger group; else one pup is isolated to form a new group of size 1. In this way, a higher probability makes larger huddles more likely to form. More precisely, the huddling algorithm involves iteratively selecting a pup at random, a, then selecting a second pup at random from a different group, b, and then either joining together the groups to which pups a and b belong with probability ρa,b, or detaching a from its group to form a new group of size 1, where ρa,b = (1 + e−T)−1, (2.1) (2.1) and the threshold T is referred to as the ‘temperature parameter’. Predicting how huddling statistics change over developmental time thus requires a definition of how T, which determines the likelihood of two groups joining to form a larger huddle, changes as the thermal physiology matures. Although studies of the developing thermal physiology of mice are numerous, few have quantified the relationship between the maturing thermal physiology and the development of thermal behaviour in the same animals and under the same experimental conditions. The basis of the model is therefore a dataset published by Eedy & Ogilvie [48], which describes, for the same set of mice, how the body mass, the mass-specific metabolic rate and crucially the preferred ambient temperature of the animals change across the first 60 postnatal days. In that study, animals were briefly isolated from the huddle on successive days and placed on a thermocline, i.e. an apparatus in which temperature varies continuously from hot on one side to cold on the other. rsos.royalsocietypublishing.org R.Soc. opensci. 4: 170885 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . In rodents, this may occur during postnatal development, as odour-heat conditioning between huddling littermates on November 22, 2017 http://rsos.royalsocietypublishing.org/ Downloaded from replaces the physiological drive for huddling with a drive based on the strength of association to olfactory cues. 3 hysiological drive for huddling with a drive based on the strength of association to 3 To make explicit these assumptions about the role of odour-heat conditioning in social thermoregulation, and to test the idea that social thermoregulation can provide a scaffold for the development of non-thermal social behaviours, the current study presents a model, based on the thermodynamic description of rodent huddling by Wilson [20], which predicts how huddling behaviours should change over time as BAT physiology matures in litters of mice. The model is then extended to ask how odour-heat conditioning during contact in the huddle shapes the emergent group behaviour. The model is calibrated to data on the development of thermal physiology and individual thermal behaviour in mice, and thus it may be used to generate testable predictions about the developmental time course of the emergence of social behaviour. rsos.royalsocietypublishing.org R.Soc. opensci. 4: 170885 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . In similar terms, social thermoregulation is thought to confer, in a number of species, human-like social behaviours [34,35], such as the ‘contact comfort’ offered in consolation to distressed conspecifics by prairie voles [36], bonobos [37] and chimpanzees [38]. As precocial mammals develop, maximal energy in BAT stores at birth decay, as does the drive towards huddling based on physiological demands [6,24,26,39,40]. However, rodents continue to huddle into adulthood, and the transition from physiological huddling to ‘filial huddling’ is characterized by a preference for (even cool) objects whose odours have been associated with a warm soft touch [6,39,41–44]. According to Alberts [45]: ‘The olfactory-perceptual preferences that direct and maintain social contact (huddling) behavior in rat pups are established by the association of olfactory cues with the thermotactile stimulation present during mother-litter interactions. The induction of odor preferences that guide affiliative social behaviour are not susceptible to other reinforcers such as suckling rewards.’ Thus, associative learning, and in particular odour-heat conditioning, is thought to play a primary role in the emergence of rodent social behaviour. Emerging theories of social thermoregulation in primates are beginning to extrapolate from the data on rodent huddling to explain how complex human psychological concepts, such as the establishment of distinct attachment styles, and the formation of internal models for social behaviour, may be supported by the same neural systems that regulate huddling behaviours in rats and mice [34], such as hypothalamic circuitry and oxytocin regulation [6,35,46]. A central theme in these discussions is that neural systems which evolved under selection pressure to allow animals to react to thermal stimuli, to help minimize the energetic costs of physiological thermoregulation, have since been supplanted by more elaborate (presumably neocortical) circuitry that enables animals to predict the thermal consequences of contact with conspecifics [34]. The idea has recently been developed further by Morrison [35], who proposes that ‘[Neural] pathways involved in social thermoregulation may have evolved to use conspecific touch patterns as shorthand for “warm and close”. [. . .Such] temporal and contextual shorthand may manifest in regulatory neural shortcuts in which “warm and close” states can be instigated by social touch alone, rather than requiring a cycle of behaviorally mediated physical warmth restoration following actual temperature decreases.’ Essentially, the neural substrate of social thermoregulation may provide a scaffold for the emergence of non-thermal social behaviours. 2. Models The recorded temperature of the location at which the animals settled is referred to herein as the preferred ambient temperature. The next section shows how, together with existing data describing changes in mouse BAT over a similar period [49], the preferred ambient temperature of developing mice can be related to the changing thermal physiology, and thus how the physiological drive towards huddling, T, develops. To investigate the transition from physiological to filial huddling, the data of [48,49] were first approximated by a series of simple expressions to estimate the preferred ambient temperature T; then values of T were fed through the huddling model (equation (2.1)) to predict how group sizes change during postnatal development. Corresponding to a ‘no-learning’ control condition, the algorithm begins with n = 7 pups joined in a single group, and then evaluates equation (2.1) many thousands of times, comparing ρa,b to a random number between 0 and 1 each time to determine the reconfiguration of the pups between subgroups, while T changes according to the fit to the preferred ambient temperature measured by Eedy & Ogilvie [48]. Corresponding to the main ‘learning’ condition, the same procedure is repeated, using an associative learning rule to adapt a set of associative strengths between pups, and in turn to weight T by these associative strengths, on each iteration. This extension is detailed in the final Results section and represents the ability of animals to learn, by odour-heat conditioning, to predict the outcome of future contacts. on November 22, 2017 http://rsos.royalsocietypublishing.org/ Downloaded from y yp g g p . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 0.4 0 5 10 15 20 25 30 35 0.6 0.8 brown fat per 100 g metabolism (cal g–1h–1) 1.0 1.2 (a) (b) 10 20 30 t (days) 40 50 60 P = 0 P = e–t/k G = k(1 + S), S = –kP lnP P = 1 k 0 10 20 30 t (days) 40 50 60 Figure 1. Development of mouse physiology. Data recorded by Lagerspetz [49] in (a) and Eedy & Ogilvie [48] in (b) are shown as black dots. Curves show the fit of the model. 3.1. Metabolism as the entropy of brown adipose fat tissue energy consumption The points p plotted in figure 1a show the weights of BAT, as a percentage of the body weight, as measured in mice at different ages by Lagerspetz [49]. Using the first (p1) and final (p0) measurements to define p′ = (p −p0)/(p1 −p0), the rescaled points p′ were well approximated by an exponential decay, P = e−t/k, (3.1) (3.1) with k a time constant describing the rate of depletion of BAT reserv Fi 1b h h ifi b li ( d with k a time constant describing the rate of depletion of BAT reserves. Figure 1b shows the mass-specific metabolic rate (converted to calories per gram per hour) reported by Eedy & Ogilvie [48], and a fit to these data by G, defined as S = −kP ln P (3.2) S = −kP ln P (3.2) S = −kP ln P (3.2) and G = k(1 + S), (3.3) (3.3) where the unit term corresponds to the basal metabolic rate and S is the entropy associated with P. As such, k is a unit of energy, and the fit obtained using k = 8.31 ascribes particular significance to k as the universal gas constant [50]. Thus the mass-specific metabolic rate is proposed to be the thermodynamic entropy generated by the conversion of energy that is stored in BAT at birth. where the unit term corresponds to the basal metabolic rate and S is the entropy associated with P. As such, k is a unit of energy, and the fit obtained using k = 8.31 ascribes particular significance to k as the universal gas constant [50]. Thus the mass-specific metabolic rate is proposed to be the thermodynamic entropy generated by the conversion of energy that is stored in BAT at birth. Entropy is a measure of disorder, describing the number of different configurations of a system that are possible. Only in open systems can entropy decrease, i.e. in systems that exchange matter with the surrounding environment. From day 8, figure 1 shows a decrease in the entropy (per unit mass) that relates the amount of BAT to the rate of metabolism. This suggests that as the mouse uses energy stored in BAT, and exchanges matter with its environment via respiration, the number of possible states of the brown fat tissue decreases from day 8. 2. Models (a) The depletion of brown adipose fat reserves was modelled as an exponential decay, P, with a timeconstantofk = 8.31.(b)Themass-specificmetabolicrate,G,wasmodelledintermsoftheentropy,S,associatedwithP.According to this model, the mass-specific metabolic rate is predicted to peak at postnatal day k = 8.31. 4 rsos.royalsocietypublishing.org R.Soc. opensci. 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 5 10 15 20 25 30 35 metabolism (cal g–1h–1) (b) G = k(1 + S), S = –kP lnP k 0 10 20 30 t (days) 40 50 60 0 0.4 0.6 0.8 brown fat per 100 g 1.0 1.2 (a) 10 20 30 t (days) 40 50 60 P = 0 P = e–t/k P = 1 4 rsos.royalsocietypublishing.org R.Soc. opensci. 4: 170885 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Figure 1. Development of mouse physiology. Data recorded by Lagerspetz [49] in (a) and Eedy & Ogilvie [48] in (b) are shown as black dots. Curves show the fit of the model. (a) The depletion of brown adipose fat reserves was modelled as an exponential decay, P, with a timeconstantofk = 8.31.(b)Themass-specificmetabolicrate,G,wasmodelledintermsoftheentropy,S,associatedwithP.According to this model, the mass-specific metabolic rate is predicted to peak at postnatal day k = 8.31. A full implementation of the model in C++ is included as electronic supplementary material, S1, together with a script, written in Python, to extract and display the changing huddling statistics, i.e. the average group size predicted on each postnatal day. A full implementation of the model in C++ is included as electronic supplementary material, S1, together with a script, written in Python, to extract and display the changing huddling statistics, i.e. the average group size predicted on each postnatal day. 3.1. Metabolism as the entropy of brown adipose fat tissue energy consumption 0 5 10 weight (g) 15 20 25 30 k 0 10 20 30 t (days) 40 50 60 M = k(1 – P) W = M + ce–kT1 (a) 5 Figure 2. Development of mouse behavioural thermoregulation. Data recorded by Eedy & Ogilvie [48] are shown as black dots. Curves show the fit of the model. (a) The growth curve was modelled as a muscle mass M, plus a non-muscle mass that rises as temperature T1 falls. (b) The environment temperature selected by mice on a thermocline was modelled as a combination of temperatures T1 and T2, related to the development of muscle and non-muscle masses, respectively. The model suggests that behavioural thermoregulation (b) is driven by the developing metabolism, defined in terms of the entropy associated with brown adipose fat depletion. 3.1. Metabolism as the entropy of brown adipose fat tissue energy consumption Intuitively, the effect is similar to the way that water molecules become more ordered when they freeze to create ice. on November 22, 2017 http://rsos.royalsocietypublishing.org/ Downloaded from 5 rsos.royalsocietypublishing.org R.Soc. opensci. 4: 170885 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 5 10 weight (g) 15 20 25 30 k 0 32 33 34 preference (°C) 35 36 37 38 39 10 20 30 t (days) 40 50 60 0 10 20 30 t (days) 40 50 60 M = k(1 – P) W = M + ce–kT1 Tp+ [T1µ P] Tp– [T2µ G(W – M)] Tp (a) (b) Figure 2. Development of mouse behavioural thermoregulation. Data recorded by Eedy & Ogilvie [48] are shown as black dots. Curves show the fit of the model. (a) The growth curve was modelled as a muscle mass M, plus a non-muscle mass that rises as temperature T1 falls. (b) The environment temperature selected by mice on a thermocline was modelled as a combination of temperatures T1 and T2, related to the development of muscle and non-muscle masses, respectively. The model suggests that behavioural thermoregulation (b) is driven by the developing metabolism, defined in terms of the entropy associated with brown adipose fat depletion. 5 rsos.royalsocietypublishing.org R.Soc. opensci. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 33 34 preference (°C) 35 36 37 38 39 0 10 20 30 t (days) 40 50 60 Tp+ [T1µ P] Tp– [T2µ G(W – M)] Tp (b) 5 rsos.royalsocietypublishing.org R.Soc. opensci. 4: 170885 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2. Behavioural thermoregulation as a competition between fat and muscle The growth curves of mice typically display an initial rise (of decreasing magnitude) followed by the more familiar sigmoidal shape that is often modelled as a logistic/autocatalytic function (e.g. [51–53]; see electronic supplementary material, figure S2). Figure 2a shows that the growth curves measured by Eedy & Ogilvie [48] are well described as sums of two quantities, M = k(1 −P) (3.4) (3.4) and and W = M + c e−kT1, (3.5) (3.5) where c = 19 is a constant (see electronic supplementary material, figure S2) and T1 is a temperature. where c = 19 is a constant (see electronic supplementary material, figure S2) and T1 is a temperature. Viewed in terms of the growth rates, the growth curve comprises a mass M that is driven towards a saturating value of k by dM/dt = k −M, and a second mass N = W −M, which increases with M at a rate that decreases as M →k, according to dN/dM ∝N. The initial rise in N occurs at around postnatal day 15, which for mice coincides with a rapid development of muscle shivering as a response to cold challenge [49]. The quantity M is thus interpreted to be the muscle mass and the quantity N is therefore referred to as the non-muscle mass. The temperatures selected by the developing mice (when isolated) on a thermocline, as recorded by Eedy & Ogilvie [48], are shown in figure 2b. Selected temperatures could also be approximated by a combination of two curves, when added to a ‘target’ adult body temperature assumed to be Tp ≈36◦C: T1 ∝P (3.6) (3.6) T1 ∝P and T2 ∝GN, (3.7) (3.7) T2 ∝GN, where the constants of proportionality were estimated as c1 = 3 and c2 = 0.025, respectively. here the constants of proportionality were estimated as c1 = 3 and c2 = 0.025, respectively. On each postnatal day, the animals appear to select either Tp + T1 or Tp −T2, suggesting that thermoregulatory systems based on BAT energy metabolism (responsible for T1) and total (non-muscle) metabolism (responsible for T2) are in competition for behavioural thermoregulation. Compared with the dominance of BAT in determining the preferred temperature in the first few postnatal days, the later dominance of other thermoregulatory systems represented by T2 may correspond with increases in e.g. liver, thyroid and adrenal activity [49]. on November 22, 2017 http://rsos.royalsocietypublishing.org/ Downloaded from 6 rsos.royalsocietypublishing.org R.Soc. opensci. 3.2. Behavioural thermoregulation as a competition between fat and muscle In the control condition, the predicted mean group size decreases with T (light trace), but with associative learning enabled (heavy trace) high huddling levels remain stable into adulthood, with huddling dominated by ‘filial’ preferences(basedonα)ratherthanphysiology(basedonT)fromapproximatelyday15.(b)Developmentoftheassociativestrengthsof an arbitrary pup to the odours of its littermates in the ‘learning’ condition. Heavier traces highlight the emergent heterogeneity of filial huddling preferences (litter size; n = 7). 3.2. Behavioural thermoregulation as a competition between fat and muscle 4: 170885 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 1.0 –0.05 0 0.05 0.10 0.15 0.20 0.25 control learning a1,2, a1,3 ...a1,n 1.5 2.0 2.5 huddle size association 3.0 3.5 4.0 10 20 30 t (days) 40 50 60 0 10 20 30 t (days) 40 50 60 (a) (b) Figure 3. From physiological huddling to filial huddling. (a) Huddling statistics were generated by supplying a Monte Carlo model [20] with temperatures T = T1 −T2, weighted either by α = 1 to define a ‘physiological huddling’ control condition, or by allowing associative strengths αa,b to adapt. In the control condition, the predicted mean group size decreases with T (light trace), but with associative learning enabled (heavy trace) high huddling levels remain stable into adulthood, with huddling dominated by ‘filial’ preferences(basedonα)ratherthanphysiology(basedonT)fromapproximatelyday15.(b)Developmentoftheassociativestrengthsof an arbitrary pup to the odours of its littermates in the ‘learning’ condition. Heavier traces highlight the emergent heterogeneity of filial huddling preferences (litter size; n = 7). –0.05 0 0.05 0.10 0.15 0.20 0.25 a1,2, a1,3 ...a1,n association 0 10 20 30 t (days) 40 50 60 (b) 6 rsos.royalsocietypublishing.org R.Soc. opensci. 4: 170885 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 1.0 control learning 1.5 2.0 2.5 huddle size 3.0 3.5 4.0 10 20 30 t (days) 40 50 60 (a) 6 association rom physiological huddling to filial huddling. (a) Huddling statistics were generated by supplying a Monte Carlo model [20]i Figure 3. From physiological huddling to filial huddling. (a) Huddling statistics were generated by supplying a Monte Carlo model [20] with temperatures T = T1 −T2, weighted either by α = 1 to define a ‘physiological huddling’ control condition, or by allowing associative strengths αa,b to adapt. 7 rsos.royalsocietypublishing.org R.Soc. opensci. 4: 170885 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The quantities and expressions derived in modelling the data of [48,49] suggest the following about the development of the thermal physiology and behaviour of the mouse. Mice are born with maximum BAT stores, which decrease exponentially over time as P = e−t/k, as is the typical profile for a precocial mammal [23]. From birth, mice accumulate body mass by a process that converts between fat and muscle, such that muscle mass increases as M = k(1 −P). As such, the unit of energy k may be interpreted as a conversion factor between the (mass-specific) energy stored in fat tissue and the (absolute) muscle mass. The energy released in the conversion between fat and muscle is reflected by a spike in the entropy of BAT, measured as a peak in the mass-specific metabolic rate, i.e. the oxygen consumption. This spike is similar to the fluctuation in entropy (or heat capacity) measured by physicists during a Schottky anomaly (see [50,55]), or as occurs when an open system undergoes a transition from a low-energy ground state to a steady state of higher energy [56]. Here, the ground state corresponds to ectothermy, and the transition is to the higher-energy thermal physiology associated with endothermy. Ectothermy in the newborn makes it highly resistant to a cold environment, for example neonatal mice can recover from hypothermia at 0◦C, whereas adults cannot [49]. However, the later transition to endothermy, through a peak in entropy, is required in order for the adult to sustain a higher energy metabolism; In the words of Erwin Schrödinger ‘. . .the higher temperature of the warm-blooded animal includes the advantage of enabling it to get rid of its entropy at a quicker rate, so that it can afford a more intense life process’ [57]. g g py q p The results of adding odour-heat conditioning to the model of [20] provides a parsimonious explanation for the persistence of rodent filial huddling into adulthood, confirming the intuitions of several researchers (e.g. [34,35,45]). Equation (3.9) makes explicit the distinction between reactive behaviour (i.e. physiological huddling with all α = 1; figure 3a, ‘control’) and predictive behaviour (i.e. filial huddling based on a learnt distribution of α values among littermates; figure 3a, ‘learning’). More detailed models of associative learning are expected to yield qualitatively similar results. 7 rsos.royalsocietypublishing.org R.Soc. opensci. 4: 170885 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Beyond the a priori prediction that odour-heat conditioning might lead to the persistence of huddling into adulthood, the additional prediction that associative strengths among the litter can develop to be increasingly positive or negative was not anticipated, although the effect is simple to understand post hoc. Once two pups have developed a moderate association, an early contact that by chance results in a surprising outcome will lead to an adjustment in association that makes that predicted outcome less likely to result from future encounters. For example, two pups that expect to maintain contact (α > 0) but do not, will adjust α to predict that future contacts are unlikely to be maintained (α < 0), and in doing so reduce the probability of maintaining future contacts. Steady increases or steady decreases in associative strength between pups (figure 3b) thus reflect an amplification of early individual differences between them and result from closing the loop between behaviour (equation (2.1)) and learning (equation (3.9)). By driving the summation term in equation (3.9) towards binary values of r, the overall associative strengths among the group remain bounded, thus enforcing a competition where pairwise increases and decreases in associative strength are balanced. The net effect is a steady state in which the system remains poised in a critical regime (ρ ≈0.5). These dynamics demonstrate the usefulness of computational modelling as a tool for teasing out the predictions of how even simple systems behave when learning is allowed to interact with behaviour. The new prediction in this case is that while associative learning enables huddling to persist into adulthood, individuals will become increasingly selective in their choice of huddling partners. This prediction could in principle be tested by measuring the changing preferences of animals, at thermoneutral temperatures, to huddle with surrogate objects scented with different littermate odours in a forced-choice experimental set-up. In similar set-ups using artificial odours, rats have been shown to spend more time on postnatal day 6 exploring odours recently paired with the experience of warmth, whereas on days 7 and 8 rats spend less time exploring an odour paired with the experience of cold, compared to baseline times spent exploring the warmer of two odour-neutral locations [44]. Filial huddling preferences can be induced by exposure to novel odours when paired with soft contacts and/or warm environments (rather than food [58]). 3.3. From physiological huddling to filial huddling The Monte Carlo method developed by Wilson [20] (equation (2.1)) can be used to translate T1 and T2 into a prediction of how the mean group size varies with age as the physiology matures from ectothermy to endothermy, using T ∝T1 −T2. Figure 3a (light trace) confirms that huddling (average group size) is predicted to decrease as the preferred temperature falls. To model how pups learn from huddling interactions, each is assumed to maintain a strength of association α for the odour of each of its littermates. The thermodynamic temperature parameter T is then weighted at each time step by the strength of association of pup b for the odour of pup a, T = αb,a(T1 −T2)β, (3.8) (3.8) where β = 0.2 is an arbitrary scaling constant. Note that in the control condition, where huddling interactions are determined only by the maturing physiology, α = 1 for all strengths of association. The Delta rule from animal learning theory [54] can then be used to modify these associative strengths, treating each simulated encounter between a and b as a conditioning trial. On each iteration of the huddling algorithm, the strength of association of pup a for the odour of pup b, αa,b, is updated to better predict whether future contacts between them will be maintained, αa,b = γ ⎛ ⎝r −  i̸=a αa,i ⎞ ⎠, (3.9) (3.9) where the reward is r ≡1 whenever the groups of a and b are combined, or r ≡0 otherwise, and the learning rate is set to γ = 0.001. where the reward is r ≡1 whenever the groups of a and b are combined, or r ≡0 otherwise, and the learning rate is set to γ = 0.001. Figure 3a (heavy trace) shows that when littermates can learn to predict the outcome of huddling interactions, large huddles persist into adulthood, with larger huddles predicted from around day 15 in littermates able to learn compared to non-learning controls. Figure 3b shows the associative strengths learnt by an arbitrary pup, which grow to an early peak for all littermates, but thereafter increasingly discriminate among the littermates. The development of two associative strengths are highlighted, showing how littermates can learn strong positive or negative associations to one another. This emergent heterogeneity of preferences for maintaining contacts with specific littermates may constitute the basis of a rudimentary social system. on November 22, 2017 http://rsos.royalsocietypublishing.org/ Downloaded from 4. Discussion 7 References Biosci.Landmark 16, 1428–1444. (doi:10.2741/ 3797) 1. Ocko SA, Mahadevan L. 2014 Collective thermoregulation in bee clusters. J.R.Soc.Interface 11, 20131033. (doi:10.1098/rsif.2013.1033) thermoregulatory huddling. PLoSComput.Biol. 13, 1–22. (doi:10.1371/journal.pcbi.1005378) 21. Alberts JR. 1978 Huddling by rat pups: multisensory controlofcontactbehavior.J.Comp.Physiol.Psychol. 92, 220–230. (doi:10.1037/h0077458) 11. Eppley TM, Watzek J, Dausmann KH, Ganzhorn JU, Donati G. 2017 Huddling is more important than rest site selection for thermoregulation in southern bamboo lemurs. Anim.Behav. 127, 153–161. (doi:10.1016/j.anbehav.2017.03.019) 2. Gregory PT. 1984 Communal denning in snakes. In Contributionstovertebrateecologyandsystematics: atributetoHenryS.Fitch (eds RA Seigel, LE Hunt, JL Knight, L Malaret, NL Zuschlag), pp. 57–75. Lawrence, KS: University of Kansas, Museum of Natural History. 2. Gregory PT. 1984 Communal denning in snakes. In Contributionstovertebrateecologyandsystematics: atributetoHenryS.Fitch (eds RA Seigel, LE Hunt, JL Knight, L Malaret, NL Zuschlag), pp. 57–75. Lawrence, KS: University of Kansas, Museum of Natural History. 22. Alberts JR. 2012 Observe, simplify, titrate, model, and synthesize: a paradigm for analyzing behavior. Behav.BrainRes. 231, 250–261. (doi:10.1016/j.bbr. 2012.03.007) 12. Gordon CJ. 1990 Thermal biology of the laboratory rat. Physiol.Behav. 47, 963–991. (doi:10.1016/ 0031-9384(90)90025-Y) 23. CannonB,NedergaardJ.2004Brownadiposetissue: function and physiological significance. Physiol.Rev. 84, 277–359. (doi:10.1152/physrev.00015.2003) 3. Waters A, Blanchette F, Kim AD. 2012 Modeling huddling penguins. PLoSONE 7, e50277. (doi:10.1371/journal.pone.0050277) 13. Gordon CJ. 2012 Thermal physiology of laboratory mice: defining thermoneutrality. J.Therm.Biol. 37, 654–685. (doi:10.1016/j.jtherbio.2012.08.004) 84, 277–359. (doi:10.1152/physrev.00015.2003) 24. Morrison SF. 2004 Central pathways controlling brown adipose tissue thermogenesis. NewsPhysiol. Sci. 19, 67–74. (doi:10.1152/nips.01502.2003) 4. Russo D etal. 2017 Sociality influences thermoregulation and roost switching in a forest bat using ephemeral roosts. Ecol.Evol. 7, 5310–5321. (doi:10.1002/ece3.3111) 14. Schank JC, Alberts JR. 1997 Self-organized huddles of rat pups modeled by simple rules of individual behavior. J.Theor.Biol. 189, 11–25. (doi:10.1006/ jtbi.1997.0488) 25. Sokoloff G, Blumberg MS. 2001 Competition and cooperation among huddling infant rats. Dev. Psychobiol. 39, 65–75. (doi:10.1002/dev.1030) 5. Canals M, Bozinovic F. 2011 Huddling behavior as critical phase transition triggered by low temperatures. Complexity 17, 35–43. (doi:10.1002/ cplx.20370) 15. Schank JC, Alberts JR. 2000 The developmental emergence of coupled activity as cooperative aggregation in rat pups. Proc.R.Soc.Lond.B 267, 2307–2315. (doi:10.1098/rspb.2000.1284) 26. Sokoloff G, Blumberg MS. 2002 Contributions of endothermy to huddling behavior in infant Norway rats (Rattusnorvegicus) and Syrian golden hamsters (Mesocricetusauratus). J.Comp.Psychol. 116, 240–246. (doi:10.1037/0735-7036.116.3.240) 6. Alberts JR. 2007 Huddling by rat pups: ontogeny of individual and group behavior. Dev.Psychobiol. 49, 22–32. (doi:10.1002/dev.20190) 16. Schank JC. 2008 The development of locomotor kinematics in neonatal rats: an agent-based modeling analysis in group and individual contexts. rsos.royalsocietypublishing.org R.Soc. opensci. 4: 170885 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . According to the model, mechanisms of classical conditioning, which presumably involve the pre- optic region of the hypothalamus [23,24,46,60–62] and the olfactory bulb [39], adjust the relative strengths of association to the smells of littermates to better predict the thermal consequences of huddling encounters. As a result, huddling levels are maintained into adulthood, despite a decline in the immediate energetic benefits to huddling. In the process, the thermodynamic entropy is essentially converted into an information-theoretic entropy, storing among the relative strengths of association information about the history of rewarding and non-rewarding thermotactile experiences between littermates. This information represents a potential template for an adult social system in which animals prefer to interact with certain others. Data accessibility. The datasets supporting this article have been uploaded as part of the electronic supplementary material. mpeting interests. I declare I have no competing interests Funding. I received no funding for this study. Funding. I received no funding for this study. Acknowledgements. The author is grateful to Hannes Saal and Tony Prescott at the University of Sheffield and Paul Wilson at the University of Hull for useful discussions. For Pippa April Wilson. 7 rsos.royalsocietypublishing.org R.Soc. opensci. 4: 170885 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The efficacy with which the association between odour and a warm soft touch can induce filial responses increases from birth [59] during the first two postnatal weeks [41], affecting huddling behaviours until around day 15 [45]. Consistent with these data, the point at which the two traces in figure 3a intersect defines a transition from physiological to filial huddling, i.e. at around postnatal day 15. Day 15 represents a landmark in the development of rat social thermoregulation. Preferences measured in rats on day 15 can be induced by a single 2 h exposure at postnatal day 14 to a scented object other than the mother, only if it is both warm and soft (consistent with the definition of r), suggesting on November 22, 2017 http://rsos.royalsocietypublishing.org/ Downloaded from on November 22, 2017 http://rsos.royalsocietypublishing.org/ Downloaded from that a combination of the thermal and tactile properties of a contact determine its valence as a reward for odour conditioning. The emergence of filial huddling shown in figure 3a is thus consistent with the general finding that preferences for conspecifics are stronger for older (15–20 days) animals than younger animals (5–10 days), and are disrupted in older animals to a greater extent by blocking olfaction (e.g. by intranasal infusion of zinc sulphate) [39]. An important test of the model will be to establish whether day 15 is also a landmark in the development of mouse social behaviour. 8 9 rsos.royalsocietypublishing.org R.Soc. opensci. 4: 170885 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31. Rödel HG, Meyer S. 2011 Early development influences ontogeny of personality types in young laboratory rats. Dev.Psychobiol. 53, 601–613. (doi:10.1002/dev.20522) 52. Richards FJ. 1959 A flexible growth model for empirical use. J.Exp.Bot. 10, 290–301. (doi:10.1093/ jxb/10.2.290) 41. Kojima S, Alberts JR. 2009 Maternal care can rapidly induce an odor-guided huddling preference in rat pups. Dev.Psychobiol. 51, 95–105. (doi:10.1002/ dev.20349) 32. Hudson R, Bautista A, Reyes-Meza V, Montor JM, Rödel HG. 2011 The effect of siblings on early development: a potential contributor to personality differences in mammals. Dev.Psychobiol. 53, 564–574. (doi:10.1002/dev.20535) 53. Yamauchi C, Fujita S, Obara T, Ueda T. 1983 Effects of room temperature on reproduction, body and organ weights,foodandwaterintakes,andhematologyin mice. JikkenDobutsu 32, 1–11. (doi:10.1538/expanim 1978.32.1_1) 42. Gilbert C, McCafferty Y, Le Maho D, Martrette JM, Giroud S, Blanc S, Ancel A. 2010 One for all and all for one: the energetic benefits of huddling in endotherms. Biol.Rev.Camb.Philos.Soc. 85, 545–569. (doi:10.1111/j.1469-185X.2009.00115.x) 33. Bautista A, Zepeda JA, Reyes-Meza V, Féron C, Rödel HG, Hudson R. 2017 Body mass modulates huddling dynamics and body temperature profiles in rabbit pups. Physiol.Behav. 179, 184–190. (doi:10.1016/j.physbeh.2017.06.005) 54. Rescorla RA, Wagner AR. 1972 A theory of Pavlovian conditioning: variations in the effectiveness of reinforcement and nonreinforcement. In Classical ConditioningII:CurrentResearchandTheory, AppletonCenturyCrofts (eds AH Black, WF Prokasy), pp. 64–99. New York, NY: Appleton Century Crofts. 43. Kojima S, Alberts JR. 2011 Warmth from skin-to-skin contact with mother is essential for the acquisition of filial huddling preference in preweanling rats. Dev.Psychobiol. 53, 813–827. (doi:10.1002/dev. 20565) 34. IJzerman H, Coan J, Wagemans F, Missler M, Van Beest I, Lindenberg S, Tops M. 2015 A theory of social thermoregulation in human primates. Front. Psychol. 6, 1–17. (doi:10.3389/fpsyg.2015. 00464) 55. MacKay DJC. 2003 Informationtheory,inference,and learningalgorithms. Cambridge, UK: Cambridge University Press. 44. Bollen B, Matrot B, Ramanantsoa N, Van den Bergh O, D’Hooge R, Gallego J. 2012 Olfactory classical conditioning in neonatal mouse pups using thermal stimuli. Behav.BrainRes. 229, 250–256. (doi:10.1016/j.bbr.2011.12.030) 56. Von Bertalanffy L. 1968 Generalsystemtheory: foundations,development,applications. New York, NY: George Braziller. 35. Morrison I. 2016 Keep calm and cuddle on: social touch as a stress buffer. Adapt.Human.Behav. Physiol. 2, 344–362. (doi:10.1007/s40750-016- 0052-x) 45. Alberts JR, May B. 1984 Nonnutritive, thermotactile induction of filial huddling in rat pups. Dev. Psychobiol. 17, 161–181. (doi:10.1002/dev.420170207) 57. Schrödinger E. 2005 Whatislife? Cambridge, UK: Cambridge University Press. 36. Burkett JP, Andari E, Johnson ZV, Curry DC, de Waal FBM, Young LJ. References J.Theor.Biol. 254, 826–842. (doi:10.1016/j.jtbi. 2008.07.024) 27. Blumberg MS. 1997 Ontogeny of cardiac rate regulation and brown fat thermogenesis in golden hamsters (Mesocricetusauratus). J.Comp.Physiol.B 167, 552–557. (doi:10.1007/s003600050108) 7. Rödel HG, Von Holst D, Kraus C. 2009 Family legacies: short- and long-term fitness consequences of early-life conditions in female European rabbits. J.Anim.Ecol. 78, 789–797. (doi:10.1111/j.1365-2656.2009.01537.x) 17. May CJ, Schank JC, Joshi S. 2011 Modelling the influence of morphology on the movement ecology of groups of infant rats (Rattusnorvegicus). Adapt. Behav. 19, 280–291. (doi:10.1177/1059712311413476) 28. Haig D. 2008 Huddling: brown fat, genomic imprinting and the warm inner glow. Curr.Biol. 18, R172–R174. (doi:10.1016/j.cub.2007.12.040) 8. Sanchez ER, Solis R, Torres-Contreras H, Canals M. 2015 Self-organization in the dynamics of huddling behavior in Octodondegus in two contrasting seasons. Behav.Ecol.Sociobiol. 69, 787–794. (doi:10.1007/s00265-015-1894-0) 8. Sanchez ER, Solis R, Torres-Contreras H, Canals M. 2015 Self-organization in the dynamics of huddling behavior in Octodondegus in two contrasting seasons. Behav.Ecol.Sociobiol. 69, 787–794. (doi:10.1007/s00265-015-1894-0) 29. Harshaw C, Culligan JJ, Alberts JR. 2014 Sex differences in thermogenesis structure behavior and contact within huddles of infant mice. PLoSONE 9, e87405. (doi:10.1371/journal.pone. 0087405) 18. Glancy J, Groß R, Stone JV, Wilson SP. 2015 A self-organising model of thermoregulatory huddling. PLoSComput.Biol. 11, e1004283. (doi:10.1371/journal.pcbi.1004283) 9. Canals M, Rosenmann M, Bozinovic F. 1989 Energetics and geometry of huddling in small mammals. J.Theor.Biol. 141, 181–189. (doi:10.1016/ S0022-5193(89)80016-5) 19. Glancy J, Stone JV, Wilson SP. 2016 How self-organization can guide evolution. R.Soc.open. sci. 3, 160553. (doi:10.1098/rsos.160553) 30. Reyes-Meza V, Hudson R, Martínez-Gómez M, Nicolás L, Rödel HG, Bautista A. 2011 Possible contribution of position in the litter huddle to long-term differences in behavioral style in the 20. Wilson SP. 2017 Self-organised criticality in the evolution of a thermodynamic model of rodent 20. Wilson SP. 2017 Self-organised criticality in the evolution of a thermodynamic model of rodent 10. Terrien J, Perret M, Aujard F. 2011 Behavioral thermoregulation in mammals: a review. Front. on November 22, 2017 http://rsos.royalsocietypublishing.org/ Downloaded from on November 22, 2017 http://rsos.royalsocietypublishing.org/ Downloaded from 51. Von Bertalanffy L. 1957 Quantitative laws in metabolism and growth. Q.Rev.Biol. 32, 217–231. (doi:10.1086/401873) domestic rabbit. Physiol.Behav. 104, 778–785. (doi:10.1016/j.physbeh.2011.07.019) thermogenesis during postnatal development. Behav.Neurosci. 121, 1333–1341. (doi:10.1037/ 0735-7044.121.6.1333) domestic rabbit. Physiol.Behav. 104, 778–785. (doi:10.1016/j.physbeh.2011.07.019) 9 9 rsos.royalsocietypublishing.org R.Soc. opensci. 4: 170885 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2016 Oxytocin-dependent consolation behavior in rodents. Science 351, 375–378. (doi:10.1126/science.aac4785) 46. Moriceau S, Sullivan R. 2004 Neurobiology of infant attachment. Dev.Psychobiol. 47, 230–242. (doi:10.1002/dev.20093) 58. Brunjes PC, Alberts JR. 1979 Olfactory stimulation induces filial preferences for huddling in rat pups. J.Comp.Physiol.Psychol. 93, 548–555. (doi:10.1037/h0077571) 47. Wilson SP. 2017 Self-organising thermoregulatory huddling in a model of soft deformable littermates. In BiomimeticandBiohybridSystems (eds M Mangan, A Mura, PF Verschure, TJ Prescott), pp. 1–13. Lecture Notes in Computer Science, vol. 10384. Berlin, Germany: Springer. 37. Clay Z, de Waal FBM. 2013 Development of socio-emotional competence in bonobos. Proc.Natl Acad.Sci.USA 110, 18 121–18 126. (doi:10.1073/pnas. 1316449110) 59. Bouslama M, Durand L, Chauvière E, Van den Bergh O, Gallego J. 2005 Olfactory classical conditioning in newborn mice. Behav.Brain.Res. 161, 102–106. (doi:10.1016/j.bbr.2005.01.010) 38. Romero T, Castellanos MA, de Waal FBM. 2010 Consolation as possible expression of sympathetic concern among chimpanzees. Proc.NatlAcad.Sci. USA 107, 12 110–12 115. (doi:10.1073/pnas. 1006991107) 38. Romero T, Castellanos MA, de Waal FBM. 2010 Consolation as possible expression of sympathetic concern among chimpanzees. Proc.NatlAcad.Sci. USA 107, 12 110–12 115. (doi:10.1073/pnas. 1006991107) 60. Boulant JA, Gonzalez RR. 1977 The effect of skin temperature on the hypothalamic control of heat loss and heat production. Brain.Res. 120, 367–372. (doi:10.1016/0006-8993(77)90916-7) 48. Eedy JW, Ogilvie DM. 1970 The effect of age on the thermal preference of white mice (Musmusculus) and gerbils (Merionesunguiculatus). Can.J.Zool. 48, 1301–1306. (doi:10.1139/z70-221) 61. Boulant JA. 2000 Role of the preoptic-anterior hypothalamus in thermoregulation and fever. Clin. Infect.Dis. 31, S157–S161. (doi:10.1086/317521) 49. Lagerspetz KYH. 1966 Postnatal development of thermoregulation in laboratory mice. Helgoländer wissenschaftlicheMeeresuntersuchungen 14, 559–571. (doi:10.1007/BF01611645) 39. Alberts JR, Brunjes PC. 1978 Ontogeny of thermal and olfactory determinants of huddling in the rat. J.Comp.Physiol.Psychol. 92, 897–906. (doi:10.1037/ h0077533) 62. Conti B etal. 2006 Transgenic mice with a reduced core body temperature have an increased life span. Science 314, 825–828. (doi:10.1126/science. 1132191) 40. Farrell WJ, Alberts JR. 2007 Rat behavioral thermoregulation integrates with nonshivering 50. Mandl F. 1988 Statisticalphysics. New York, NY: John Wiley and Sons. 50. Mandl F. 1988 Statisticalphysics. New York, NY: John Wiley and Sons.
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A computational model to predict the Diels–Alder reactivity of aryl/alkyl-substituted tetrazines
Monatshefte für Chemie
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& Hannes Mikula hannes.mikula@tuwien.ac.at Introduction Abstract The tetrazine ligation is one of the fastest bioorthogonal ligations and plays a pivotal role in time- critical in vitro and in vivo applications. However, pre- diction of the reactivity of tetrazines in inverse electron demand Diels–Alder-initiated ligation reactions is not straight-forward. Commonly used tools such as frontier molecular orbital theory only give qualitative and often even wrong results. Applying density functional theory, we have been able to develop a simple computational method for the prediction of the reactivity of aryl/alkyl-substituted tetrazines in inverse electron demand Diels–Alder reactions. Tetrazine ligations (TLs) are bioorthogonal inverse elec- tron demand Diels–Alder (IEDDA) initiated cycloadditions proceeding with exceptional high second-order rates of up to 3,300,000 M-1 s-1 [1]. In TLs, an 1,2,4,5-tetrazine (Tz) reacts with an electron-rich dienophile in an IEDDA reaction followed by cycloreversion under the loss of nitrogen (Fig. 1). Strained alkenes such as norbornenes [2, 3], cyclopropenes [4, 5], and trans-cyclooctenes (TCOs) [1, 6–8] are commonly used dienophiles, with TCOs pro- viding the highest reactivity. The rate-determining step is the Diels–Alder cycloaddition, while the cycloreversion has only a low energy barrier and is suspected to show strong non-statistical effects [9]. Graphical Abstract Graphical Abstract Keywords Cycloadditions  Computational chemistry  Click chemistry  Bioorthogonal chemistry Due to the high reaction rates, these ligations can be used in time-critical applications such as rapid radiolabel- ing and pretargeted PET imaging [10–16] and provide high yields within short reaction times even at low concentra- tions as usually encountered in radiochemistry and in vivo. Therefore, kinetics is one of the most important charac- teristics of bioorthogonal reactions. However, prediction of reactivities using the chemist’s understanding of organic chemistry, especially of IEDDA reactions, might lead to wrong predictions [17] and only qualitative estimates. In addition, synthesis of tetrazines is often low yielding and involves handling or even requires the production of anhydrous hydrazine (not commercially available in Eur- ope), which limits the feasibility of screening for high Diels–Alder reactivity. Hence, there is the need of reliable computational tools to predict the reactivity of various tetrazines in TLs. Keywords Cycloadditions  Computational chemistry  Click chemistry  Bioorthogonal chemistry Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00706-017-2110-x) contains supple- mentary material, which is available to authorized users. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00706-017-2110-x) contains supple- mentary material, which is available to authorized users. 1 Institute of Applied Synthetic Chemistry, TU Wien, Vienna, Austria Monatsh Chem (2018) 149:833–837 https://doi.org/10.1007/s00706-017-2110-x Monatsh Chem (2018) 149:833–837 https://doi.org/10.1007/s00706-017-2110-x ORIGINAL PAPER A computational model to predict the Diels–Alder reactivity of aryl/alkyl-substituted tetrazines Dennis Svatunek1 • Christoph Denk1 • Hannes Mikula1 Received: 18 October 2017 / Accepted: 20 November 2017 / Published online: 29 November 2017  The Author(s) 2017. This article is an open access publication Introduction Herein, we introduce a computational model for the prediction of the reactivity of aryl/alkyl-substituted Tz in the cycloaddition with trans-cyclooctene (TCO), thus 12 3 834 D. Svatunek et al. Fig. 1 Mechanism of the bioorthogonal ligation of 1,2,4,5-tetrazine (Tz) and trans-cyclooctene (TCO) Fig. 1 Mechanism of the bioorthogonal ligation of 1,2,4,5-tetrazine (Tz) and trans-cyclooctene (TCO) eliminating the need for expensive and even dangerous synthetic work, finally enabling in silico screening for tetrazines with desired reactivity. imaging (Fig. 2). While the alkyl substituent is the same for all eight tetrazines the aryl component shows consid- erable variation including electron-rich and electron-poor aryl groups. In addition, Tz 9 and 10 were included to investigate the influence of the alkyl group and an ortho- substituted aryl residue, respectively. While 3,6-bisaryl- and 3-aryl-substituted Tz show the highest reactivity, aryl/alkyl-substituted Tz are commonly used due to higher stability [18, 19] and show favorable properties in Tz-triggered bioorthogonal elimination reac- tions [20, 21]. The second-order rate constants of Tz 1–10 in the reaction with trans-cyclooctene 11 at 25 C in anhydrous 1,4-dioxane were measured by stopped-flow spectropho- tometry, which gave rates ranging from 1.00 M-1 s-1 for electron-rich trimethoxyphenyl-substituted Tz 3 to 14.6 M-1 s-1 for Tz 8 bearing an electron withdrawing 2-pyridyl substituent (Fig. 3). A computational model to predict the Diels–Alder reactivity of aryl/alkyl-substituted… 835 a b HOMO HOMO LUMO+1 LUMO 1 2 3 4 5 6 7 8 9 10 11 -12 -10 -8 0.0 0.5 1.0 1.5 2.0 orbitalenergy / eV tetrazine HOMO LUMO LUMO+1 c Fig. 4 a HOMO, LUMO, and LUMO?1 of 3-methyl-6- phenyl-Tz (9); b HOMO of TCO (11); c energy levels of selected orbitals for tetrazines 1–10 and TCO (11) a HOMO LUMO+1 LUMO Fig. 4 a HOMO, LUMO, and LUMO?1 of 3-methyl-6- phenyl-Tz (9); b HOMO of TCO (11); c energy levels of selected orbitals for tetrazines 1–10 and TCO (11) a HOMO Fig. 4 a HOMO, LUMO, and LUMO?1 of 3-methyl-6- phenyl-Tz (9); b HOMO of TCO (11); c energy levels of selected orbitals for tetrazines 1–10 and TCO (11) LUMO LUMO+1 LUMO LUMO+1 b HOMO 1 2 3 4 5 6 7 8 9 10 11 -12 -10 -8 0.0 0.5 1.0 1.5 2.0 orbitalenergy / eV tetrazine HOMO LUMO LUMO+1 c b HOMO 1 2 3 4 5 6 7 8 9 10 11 -12 -10 -8 0.0 0.5 1.0 1.5 2.0 orbitalenergy / eV tetrazine HOMO LUMO LUMO+1 c orbitalenergy / eV tetrazine tetrazine According to the FMO theory, a smaller energy gap between the interacting orbitals facilitates the reaction. Thus, one might expect that a more electron withdrawing and thus LUMO?1-lowering substituent accelerates the reaction, while an electron-rich aryl substituent will decrease reactivity. HF/6-311?G(d,p)//M06-2X/6- 311?G(d,p)-calculated orbital energies are shown in Fig. 4c. Tz 4 and 7 bearing an electron-withdrawing tri- fluoromethyl or sulfone group, respectively, show the lowest LUMO and LUMO?1 energies. However, the tet- razine with the highest reactivity, Tz 8, has one of the highest LUMO and a rather high LUMO?1 energy within the series. As shown in Fig. 5, there is no significant correlation between the LUMO?1-energy levels and the rate constants (R2 = 0.07). This can be rationalized by the fact that FMO interactions are not the only major con- tributors to activation energies in such cycloadditions [17, 27–29]. Therefore, the FMO theory cannot be applied for the reliable prediction of the Diels–Alder reactivity of aryl/alkyl-substituted Tz. However, the calculated energies of activation (DE) of the reactions between tetrazines 1–10 and TCO (11) show excellent linear correlation with the natural logarithm of the measured rate constants, as per transition state theory (Fig. 6). M06-2X/6-311?G(d,p) calculated energies of Fig. Fig. 4 a HOMO, LUMO, and LUMO?1 of 3-methyl-6- phenyl-Tz (9); b HOMO of TCO (11); c energy levels of selected orbitals for tetrazines 1–10 and TCO (11) Results and discussion Recently, we have investigated the reactivity of several 3-aryl-6-(3-fluoropropyl)-1,2,4,5-tetrazines 1–8 as chemi- cal probes for rapid radiolabeling and pretargeted PET These experimental results were selected as a basis for the construction of a predictive computational tool. DFT was successfully used in the past by our group [16, 22] and others [7, 17, 23, 24] to predict or explain the reactivity of dienophiles and tetrazines in the tetrazine ligation. There- fore, the Minnesota density functional M06-2X in combination with the 6-311?G(d,p) basis set, was used as model chemistry. This density functional has been proven to produce accurate results for thermodynamics of cycloaddition reactions [25, 26]. was successfully used in the past by our group [16, 22] and others [7, 17, 23, 24] to predict or explain the reactivity of dienophiles and tetrazines in the tetrazine ligation. There- fore, the Minnesota density functional M06-2X in combination with the 6-311?G(d,p) basis set, was used as model chemistry. This density functional has been proven to produce accurate results for thermodynamics of cycloaddition reactions [25, 26]. Diels–Alder reactions can be described by HOMO/ LUMO interactions using the frontier molecular orbital (FMO) theory. In case of the IEDDA cycloaddition the main orbital interaction is between a low-lying unoccupied orbital of the dienophile, usually being the LUMO?1 for aryl/alkyl tetrazines (Fig. 4a) [17], and the HOMO of the electron-rich dienophile (in this case TCO, Fig. 4b). Fig. 2 Investigated aryl/alkyl substituted 1,2,4,5-tetrazines in the IEDDA reaction with trans-cyclooctene (11) Fig. 3 Second-order rate constants of tetrazines 1–10 with trans- cyclooctene (11) in 1,4-dioxane at 25 C Fig. 2 Investigated aryl/alkyl substituted 1,2,4,5-tetrazines in the IEDDA reaction with trans-cyclooctene (11) Diels–Alder reactions can be described by HOMO/ LUMO interactions using the frontier molecular orbital (FMO) theory. In case of the IEDDA cycloaddition the main orbital interaction is between a low-lying unoccupied orbital of the dienophile, usually being the LUMO?1 for aryl/alkyl tetrazines (Fig. 4a) [17], and the HOMO of the electron-rich dienophile (in this case TCO, Fig. 4b). Fig. 3 Second-order rate constants of tetrazines 1–10 with trans- cyclooctene (11) in 1,4-dioxane at 25 C Fig. 3 Second-order rate constants of tetrazines 1–10 with trans- cyclooctene (11) in 1,4-dioxane at 25 C Fig. 2 Investigated aryl/alkyl substituted 1,2,4,5-tetrazines in the IEDDA reaction with trans-cyclooctene (11) 123 123 A computational model to predict the Diels–Alder reactivity of aryl/alkyl-substituted… Experimental Table 2 Observed rate constants, concentrations of TCO (11) and the corresponding Tz, and calculated second-order rate constants of the IEDDA reaction between Tz 1–10 and 11 Table 2 Observed rate constants, concentrations of TCO (11) and the corresponding Tz, and calculated second-order rate constants of the IEDDA reaction between Tz 1–10 and 11 Reaction kobs/s-1 cTCO/M ctetrazine/M k/M-1 s-1 1 ? 11 0.003278 0.002081 0.000064 1.58 2 ? 11 0.002652 0.002096 0.00005 1.27 3 ? 11 0.00205 0.002051 0.000049 1.00 4 ? 11 0.007801 0.002015 0.00005 3.87 5 ? 11 0.002703 0.002081 0.000034 1.30 6 ? 11 0.005811 0.00196 0.000046 2.96 7 ? 11 0.009894 0.001933 0.000103 5.12 8 ? 11 0.03064 0.002096 0.00005 14.6 9 ? 11 0.00461 0.002813 0.000058 1.64 10 ? 11 0.004514 0.002224 0.000061 2.03 Kinetic measurements Kinetic measurements were performed on a SX20 stopped- flow spectrophotometer (Applied Photophysics, UK) using a 535 nm LED light source. A 4 mM solution of 11 and approximately 0.1 mM solutions of Tz 1–10 were prepared in anhydrous 1,4-dioxane (note: for correct measurements it is of utmost importance to use anhydrous 1,4-dioxane, A computational model to predict the Diels–Alder reactivity of aryl/alkyl-substituted… 6 Correlation between natural logarithm of second-order rate constants and M06-2X/6-311?G(d,p) calculated energies of activation Fig. 5 Second-order rate constants plotted against HF/6- 311?G(d,p)//M06-2X/6-311?G(d,p) calculated LUMO?1 energies of the corresponding tetrazine Fig. 6 Correlation between natural logarithm of second-order rate constants and M06-2X/6-311?G(d,p) calculated energies of activation Fig. 5 Second-order rate constants plotted against HF/6- 311?G(d,p)//M06-2X/6-311?G(d,p) calculated LUMO?1 energies of the corresponding tetrazine Fig. 6 Correlation between natural logarithm of second-order rate constants and M06-2X/6-311?G(d,p) calculated energies of activation Fig. 6 Correlation between natural logarithm of second-order rate constants and M06-2X/6-311?G(d,p) calculated energies of activation Fig. 5 Second-order rate constants plotted against HF/6- 311?G(d,p)//M06-2X/6-311?G(d,p) calculated LUMO?1 energies of the corresponding tetrazine 12 3 836 D. Svatunek et al. Table 1 Calculated total electronic energies of compounds 1–11 and transition states for the reaction between 1–10 and 11, and calculated energies of activation (DE) activation can, therefore, be used to reliably predict the reactivity of aryl/alkyl-Tz in IEDDA reactions with trans- cyclooctenes. Table 1 Calculated total electronic energies of compounds 1–11 and transition states for the reaction between 1–10 and 11, and calculated energies of activation (DE) Table 1 Calculated total electronic energies of compounds 1 11 and transition states for the reaction between 1–10 and 11, and calculated energies of activation (DE) Compound E(Tz)/hartree E(TS)/hartree DE/kJ mol-1 1 - 744.464487 - 1057.63536 4.74 2 - 783.771996 - 1096.942379 6.02 3 - 1087.994366 - 1401.164459 6.78 4 - 1081.515706 - 1394.687804 1.52 5 - 1181.953194 - 1495.123556 6.08 6 - 1257.12132 - 1570.293123 2.29 7 - 1332.328085 - 1645.501028 - 0.70 8 - 760.498963 - 1073.674144 - 6.57 9 - 566.619295 - 879.789737 5.87 10 - 641.851471 - 955.023032 2.93 TCO (11) - 313.172677 – – Compound E(Tz)/hartree E(TS)/hartree DE/kJ mol-1 Using the linear correlation between ln(k) and calculated DE, Eq. (1) can be constructed which allows the predic- tion of the rate constant of new aryl/alkyl-Tz for the reaction with TCO (11) in anhydrous 1,4-dioxane at 25 C. k ¼ e0:1963DEzþ1:460 ð1Þ k ¼ e0:1963DEzþ1:460 ð1Þ energies for Tz 1–10 and the respective transition states (for the reaction with TCO) are shown in Table 1. energies for Tz 1–10 and the respective transition states (for the reaction with TCO) are shown in Table 1. energies for Tz 1–10 and the respective transition states (for the reaction with TCO) are shown in Table 1. Synthesis Trans-cyclooctene (11) and tetrazines 9 and 10 were pre- pared following known procedures [31, 32]. The synthesis of compounds 1–8 will be published elsewhere (manuscript in preparation). We are convinced that our method will aid the devel- opment of new aryl/alkyl tetrazines for bioorthogonal applications, and represents a step forward to the devel- opment of a universal computational tool being able to predict the reactivity of tetrazines with various substitution patterns. Conclusion Prediction of the reactivity of Tz in bioorthogonal ligation reactions is essential to reduce synthetic work, the resulting costs and associated risks. However, the chemist’s pre- diction of these reactivities, mainly based on frontier molecular orbital theory, can only yield qualitative or even wrong results as shown in this work. We were able to develop a computational method for the prediction of reactivities of aryl/alkyl-substituted 1,2,4,5-tetrazines in the reaction with trans-cyclooctene based on M06-2X- calculated energies of activation. This method is compu- tationally cheap as it requires only the optimization of the tetrazine and the corresponding transition state with trans- cyclooctene at the M06-2X/6-311?G(d,p) level of theory, which can even be done on an average desktop PC within hours. Computational methods Calculations were performed at the M06-2X/6-311?G(d,p) level of theory in the gas phase using the Gaussian 09 Rev. D.01 software package [30]. Vibrational analysis was per- formed to confirm stationary points are energetic minima or transition states, respectively. Orbital energies were calcu- lated by performing a HF/6-311?G(d,p) single-point calculation on M06-2X/6-311?G(d,p) optimized structures. DE was determined by calculating the difference in ener- gies between transition state and reactants. Data analysis was preformed using Gaussview 5 and Chemcraft. XYZ coordinate files of all reactants and transition states are available as electronic supplementary material. Calculated 12 123 123 A computational model to predict the Diels–Alder reactivity of aryl/alkyl-substituted… 837 since even small amounts of water will accelerate the reaction, leading to irreproducible data). These solutions were loaded into the driver syringes and equal volumes of TCO and Tz solution were mixed, resulting in concentra- tions of 2 and 0.05 mM, respectively. The reaction progress was followed by measuring the absorption around 535 nm. All measurements were performed in triplicates. Observed reaction constants (kobs) were determined by non-linear regression (one-phase-decay) using Prism 6 (Graphpad) and second-order rate constants (k) were cal- culated from kobs. Table 2 lists kobs, cTCO, cTz and k for all reactions. 12. Rossin R, van Duijnhoven SMJ, van den Bosch SM, Robillard MS (2014) Nucl Med Biol 41:630 13. Li Z, Cai H, Hassink M, Blackman ML, Brown RCD, Conti PS, Fox JM (2010) Chem Commun 46:8043 14. Liu S, Hassink M, Selvaraj R, Yap L, Park R, Wang H, Chen X, Fox JM, Li Z, Conti PS (2013) Mol Imaging 12:121 15. Meyer JP, Houghton JL, Kozlowski P, Abdel-Atti D, Reiner T, Pillarsetty NVK, Scholz WW, Zeglis BM, Lewis JS (2016) Bioconjug Chem 27:298 16. Denk C, Svatunek D, Filip T, Wanek T, Lumpi D, Fro¨hlich J, Kuntner C, Mikula H (2014) Angew Chem Int Ed 53:9655 17. Liu F, Liang Y, Houk KN (2014) J Am Chem Soc 136:11483 18. Carlson JCT, Meimetis LG, Hilderbrand SA, Weissleder R (2013) Angew Chem Int Ed 52:6917 19. Karver MR, Weissleder R, Hilderbrand SA (2011) Bioconjug Chem 22:2263 20. Fan X, Ge Y, Lin F, Yang Y, Zhang G, Ngai WSC, Lin Z, Zheng S, Wang J, Zhao J, Li J, Chen PR (2016) Angew Chem Int Ed 55:14046 Acknowledgements Open access funding provided by TU Wien (TUW). The authors thank Heidi Fittner (TU Wien) for her support. References 27. Levandowski BJ, Houk KN (2015) J Org Chem 80:3530 28. Liu F, Paton RS, Kim S, Liang Y, Houk KN (2013) J Am Chem Soc 135:15642 1. Darko A, Wallace S, Dmitrenko O, Machovina MM, Mehl RA, Chin JW, Fox JM (2014) Chem Sci 5:3770 29. Levandowski BJ, Hamlin TA, Bickelhaupt FM, Houk KN (2017) J Org Chem 82:8668 2. Devaraj NK, Weissleder R, Hilderbrand SA (2008) Bioconjug Chem 19:2297 30. Frisch MJ, Trucks GW, Schlegel HB, Scuseria GE, Robb MA, Cheeseman JR, Scalmani G, Barone V, Petersson GA, Nakatsuji H, Li X, Caricato M, Marenich A, Bloino J, Janesko BG, Gom- perts R, Mennucci B, Hratchian HP, Ortiz JV, Izmaylov AF, Sonnenberg JL, Williams-Young D, Ding F, Lipparini F, Egidi F, Goings J, Peng B, Petrone A, Henderson T, Ranasinghe D, Zakrzewski VG, Gao J, Rega N, Zheng G, Liang W, Hada M, Ehara M, Toyota K, Fukuda R, Hasegawa J, Ishida M, Nakajima T, Honda Y, Kitao O, Nakai H, Vreven T, Throssell K, Mont- gomery Jr JA, Peralta JE, Ogliaro F, Bearpark M, Heyd JJ, Brothers E, Kudin KN, Staroverov VN, Keith T, Kobayashi R, Normand J, Raghavachari K, Rendell A, Burant JC, Iyengar SS, Tomasi J, Cossi M, Millam JM, Klene M, Adamo C, Cammi R, Ochterski JW, Martin RL, Morokuma K, Farkas O, Foresman JB, Fox DJ (2016) Gaussian 09, Rev. D.01. Gaussian Inc., Wallingford 3. Knall A-C, Hollauf M, Slugovc C (2014) Tetrahedron Lett 55:4763 ˇ 4. Yang J, Sˇecˇkut_e J, Cole CM, Devaraj NK (2012) Angew Chem Int Ed 51:7476 ˇ ngs J, Peng B, Petrone A, Henderson T, Ranasinghe 5. Yang J, Liang Y, Sˇecˇkut_e J, Houk KN, Devaraj NK (2014) Chemistry 20:3365 6. Rossin R, van den Bosch SM, Ten Hoeve W, Carvelli M, Ver- steegen RM, Lub J, Robillard MS (2013) Bioconjug Chem 24:1210 7. Taylor MT, Blackman ML, Dmitrenko O, Fox JM (2011) J Am Chem Soc 133:9646 Brothers E, Kudin KN, Staroverov VN, Keith T, Kobayashi R, Normand J, Raghavachari K, Rendell A, Burant JC, Iyengar SS, 8. Selvaraj R, Fox JM (2013) Curr Opin Chem Biol 17:753 Tomasi J, Cossi M, Millam JM, Klene M, Adamo C, Cammi R, 9. To¨rk L, Jime´nez-Ose´s G, Doubleday C, Liu F, Houk KN (2015) J Am Chem Soc 137:4749 10. Computational methods Quantum-chemical calculations were performed using the Vienna Scientific Cluster (VSC). This project has received funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No 668532 (‘Click-It’). 21. Rossin R, van Duijnhoven SMJ, ten Hoeve W, Janssen HM, Kleijn LHJ, Hoeben FJM, Versteegen RM, Robillard MS (2016) Bioconjug Chem 27:1697 22. Denk C, Svatunek D, Mairinger S, Stanek J, Filip T, Matscheko D, Kuntner C, Wanek T, Mikula H (2016) Bioconjug Chem 27:1707 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http:// creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. 23. Liang Y, Mackey JL, Lopez S, Liu F, Houk KN (2012) J Am Chem Soc 134:17904 24. Lambert WD, Scinto SL, Dmitrenko O, Boyd SJ, Magboo R, Mehl RA, Chin JW, Fox JM, Wallace S (2017) Org Biomol Chem 15:6640 25. Lan Y, Zou L, Cao Y, Houk KN (2011) J Phys Chem A 115:13906 26. Paton RS, Mackey JL, Kim WH, Lee JH, Danishefsky SJ, Houk KN (2010) J Am Chem Soc 132:9335 References Wang M, Svatunek D, Rohlfing K, Liu Y, Wang H, Giglio B, Yuan H, Wu Z, Li Z, Fox J (2016) Theranostics 6:887 31. Svatunek D, Denk C, Rosecker V, Sohr B, Hametner C, Allmaier G, Fro¨hlich J, Mikula H (2016) Monatsh Chem 147:579 11. Wu Z, Liu S, Hassink M, Nair I, Park R, Li L, Todorov I, Fox JM, Li Z, Shively JE, Conti PS, Kandeel F (2013) J Nucl Med 54:244 32. Suh S-E, Barros SA, Chenoweth DM (2015) Chem Sci 6:5128 12 123
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Clinical influence of conversion of laparoscopic sleeve gastrectomy to one anastomosis gastric bypass on gastroesophageal reflux disease
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Does Conversion of Sleeve Gastrectomy to One- Anastomosis Gastric Bypass induce Gastro- Esophageal Reflux Disease? Shlomi Rayman  (  shlomirayman@gmail.com ) Assuta Ashdod Public Hospital, Ben-Gurion University Maor Staierman  Assuta Ashdod Public Hospital, Ben-Gurion University Dan Assaf  Chaim Sheba Medical Center Jacob Rachmuth  Assuta Ashdod Public Hospital, Ben-Gurion University Idan Carmeli  Assuta Ashdod Public Hospital, Ben-Gurion University Andrei Keidar  Assuta Ashdod Public Hospital, Ben-Gurion University Research Article Keywords: Revisional surgery, sleeve gastrectomy, one-anastomosis gastric bypass, GERD, bariatric surgery Posted Date: September 27th, 2022 DOI: https://doi.org/10.21203/rs.3.rs-2081268/v1 License:   This work is licensed under a Creative Commons Attribution 4.0 International License.   Read Full License Additional Declarations: No competing interests reported. Version of Record: A version of this preprint was published at Langenbeck's Archives of Surgery on April 27th, 2023. See the published version at https://doi.org/10.1007/s00423-023-02892-7. Does Conversion of Sleeve Gastrectomy to One- Anastomosis Gastric Bypass induce Gastro- Esophageal Reflux Disease? Shlomi Rayman  (  shlomirayman@gmail.com ) Assuta Ashdod Public Hospital, Ben-Gurion University Maor Staierman  Assuta Ashdod Public Hospital, Ben-Gurion University Dan Assaf  Chaim Sheba Medical Center Jacob Rachmuth  Assuta Ashdod Public Hospital, Ben-Gurion University Idan Carmeli  Assuta Ashdod Public Hospital, Ben-Gurion University Andrei Keidar  Assuta Ashdod Public Hospital, Ben-Gurion University Research Article Keywords: Revisional surgery, sleeve gastrectomy, one-anastomosis gastric bypass, GERD, bariatric surgery Posted Date: September 27th, 2022 DOI: https://doi.org/10.21203/rs.3.rs-2081268/v1 License:   This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Additional Declarations: No competing interests reported. Version of Record: A version of this preprint was published at Langenbeck's Archives of Surgery on April 27th, 2023. See the published version at https://doi.org/10.1007/s00423-023-02892-7. Does Conversion of Sleeve Gastrectomy to One- Anastomosis Gastric Bypass induce Gastro- Esophageal Reflux Disease? Shlomi Rayman  (  shlomirayman@gmail.com ) Assuta Ashdod Public Hospital, Ben-Gurion University Maor Staierman  Assuta Ashdod Public Hospital, Ben-Gurion University Dan Assaf  Chaim Sheba Medical Center Jacob Rachmuth  Assuta Ashdod Public Hospital, Ben-Gurion University Idan Carmeli  Assuta Ashdod Public Hospital, Ben-Gurion University Andrei Keidar  Assuta Ashdod Public Hospital, Ben-Gurion University Research Article Keywords: Revisional surgery, sleeve gastrectomy, one-anastomosis gastric bypass, GERD, bariatric surgery Posted Date: September 27th, 2022 DOI: https://doi.org/10.21203/rs.3.rs-2081268/v1 License:   This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Additional Declarations: No competing interests reported. Results During the study period, 37 patients underwent revision from LSG to OAGB. Mean age at LSG and pre- OAGB were 38 ± 11.74 and 46 ± 12.75, respectively. Median follow-up time was 21.5 months (range 3– 65). DRQ and GERD-HRQL scores were obtained at a median of 14 months (range 3–51) between pre- and post-OAGB. Median RDQ score pre-OAGB vs post-OAGB was significantly reduced [30 (range 12–72) vs 14 (range 12–60), p = 0.007]. All 3 parts of the GERD- HRQL questionnaires were significantly reduced between pre-OAGB and post-OAGB: Symptoms (20; 62.5% vs 10; 31.3%, p = 0.012), overall score [15(0– 39) vs 7(0–28), p = 0.04] and subjective improvement [10; 31% vs 20; 62.5%, p = 0.025). Purpose Assess the subjective impact of GERD symptoms on patients undergoing revision from LSG to OAGB using the Diagnostic Questionnaire for GERD (DRQ) and the GERD-health related quality of life score (GERD-HRQL), prior to- and following conversion. Conversion of LSG to OAGB does not induce subjective GERD symptoms in a short-term follow up. Conversion of LSG to OAGB does not induce subjective GERD symptoms in a short-term follow up. Methods Patients undergoing revision from LSG to OAGB were prospectively followed between May 2015 and December 2020. Data retrieved included demographics, anthropometrics, previous bariatric history, time interval between LSG and OAGB, weight loss and co-morbidities. Pre- and post-OAGB DRQ and GERD- HRQL questionnaires were obtained. In case of sleeve dilatation, a partial gastrectomy was performed. Research Article Additional Declarations: No competing interests reported. Version of Record: A version of this preprint was published at Langenbeck's Archives of Surgery on April 27th, 2023. See the published version at https://doi.org/10.1007/s00423-023-02892-7. Page 1/13 Page 1/13 Introduction Over the last two decades Laparoscopic sleeve gastrectomy (LSG) has become the most popular bariatric operation performed worldwide [1]. Although LSG is frequently performed, up to 20% of patients undergo conversional operations [2–4]. Conversion of LSG to other bariatric operations is safe, feasible and effective, for multiple indications, which include inadequate weight loss, weight recidivism, gastro- esophageal reflux disease (GERD), staple line leak, sleeve stenosis and dysphagia[5–8]. Although LSG is utilized extensively, a systematic review by Laffin et al. showed that there is an indeterminate rate of post- LSG de novo GERD, with a wide diversity of reports ranging from 2.1–34.9% of post-LSG patients suffering from GERD [9–11]. The one-anastomosis gastric bypass (OAGB) has gained popularity in recent years as a primary bariatric operation and as an acceptable conversional option following LSG [8, Page 2/13 12–16]. While OAGB is being increasingly utilized as a primary and revisional bariatric operation, it remains under scrutiny for potentially inducing GERD symptoms or bile reflux [14, 17, 18]. Our aim was to assess the results of conversion of LSG to OAGB, emphasizing evaluation of the reflux symptoms with the Diagnostic Questionnaire for Gastroesophageal Reflux Disease (DRQ)[19] and the GERD-Health Related Quality of Life Questionnaire (GERD-HRQL)[20]. Our hypothesis was that conversion of LSG to OAGB does not induce or worsens GERD. Materials And Methods Following an institutional review board (IRB) approval, patients undergoing conversion of LSG to OAGB from May 2015 to December 2020 were prospectively followed and consented. Inclusion criteria included patients aged 18 years and above who previously underwent a LSG and sought revisional operative management due to weight-related indications (weight regain or insufficient weight-loss), complication- related indications (dysphagia or GERD), or both. Patients were presented with data regarding expected weight-loss and risks of complications (specifically GERD) following conversion options suitable for LSG failure which included Roux-en-Y Gastric Bypass (RYGB), Biliopancreatic Diversion with Duodenal Switch (BPD/DS), Single Anastomosis Duodeno-Ileal Bypass (SADI) and the aforementioned OAGB. Exclusion criteria included patients who opted to undergo a conversion operation other than OAGB. Data collected included demographics, anthropometrics, previous operative & bariatric history, time interval between LSG and conversion, medications and co-morbidities. All patients underwent endoscopic & fluoroscopic studies prior to undergoing conversion. The diagnostic questionnaires for GERD symptoms were compared between prior to- and following the conversion to OAGB. Weight results are expressed in change in Body Mass Index (BMI) & percent Total Weight Loss (%TWL) from the pre-LSG weight to the post-OAGB nadir weight. Perioperative complications were logged according the Clavien- Dindo Classification [21]. Patients were routinely followed up at 1, 3, 6 & 12 months post-operatively. Patients that haven’t showed up to clinic in over 12 months or have not answered a telephone, email or virtual communication were considered lost to follow up. Post-operative course Patients were allowed a clear liquid diet on day 1, discharged on day 2 and allowed a pureed diet after 2 weeks following their first office visit post-op. The drain was removed prior to discharge. All patients underwent a nutritionist consult prior to discharge with a routine diet and supplement education. All patients received daily physiotherapy care and enoxaparin injections (40-60mg od) for 1 week along with an oral PPI od for 3 months. Patients with lack of oral diet advancement underwent an UGI prior to discharge, the findings of which did not change the expected post-op course. Pre-operative Assessment All patients underwent a multidisciplinary assessment prior to approval of conversional bariatric surgery which included psychosocial, nutritional, radiological and gastroenterological assessment. Smokers were counseled for smoking cessation. An esophago-gastro-duodenoscopy (EGD) and an Upper GI fluoroscopic swallow study (UGI) were performed on all patients prior to conversional surgery. The RDQ and the GERD-HRQL questionnaires were obtained before conversion and at follow up. Pre-operative blood work analysis included an anemia panel, lipid profile, vitamin D, B12 and folic acid levels, bone densitometry, thyroid and parathyroid hormone and HbA1c. Correction of abnormal values was ensued prior to conversion.Surgical Technique Page 3/13 Page 3/13 All operations were performed laparoscopically with the patient positioned in a standard supine position and standard 5-port trocar placement. A 10mm 30o scope optic device was used. Following port placement, a liver retractor was placed and lysis of adhesions using a harmonic scalpel was performed to ensure visualization of the entire sleeve. Sleeve size assessment was made in concordance with the pre- operative UGI. In case of sleeve dilatation, a linear stapled partial-gastrectomy was ensued to resize the sleeve over a 36F-40F bougie tube. Next, the stomach was stapled proximal to the pylorus at the level of the gastric incisura, to form a long (12-18 cm) and narrow tubular pouch and a separated antral remnant. We then performed a side-to-side stapled gastro-jejunostomy anastomosis between the gastric pouch and a loop of bowel (afferent limb) measuring 200-350cm from the ligament of Treitz. Common enterotomy was closed with 2 layers of continuous 3/0 Prolene sutures. Longer afferent limbs (≥250cm) were tailored individually, following a measurement of a common channel of more than 300cm and performed in patients with weight recidivism who desired and comprehended enhanced long-term weight- loss with its following consequences. A leak test of the anastomosis was performed via a naso-gastric tube using methylene blue dye in water. A Jackson-Prat drain was left along the anastomosis and staple line of stomach. Statistical Analysis Group comparison was performed using non-parametric, Wilcoxon signed rank test for two dependent groups, and Friedman test for non-parametric comparison of more than two dependent groups. Significant levels were considered at p value <0.05. %TWL was calculated from initial weight (prior to LSG) and current weight (post-OAGB). Results During the study period, 37 patients underwent conversion from LSG to OAGB, with 5 patients (13%) lost to follow up. Of the remaining 32 patients undergoing conversion from LSG to OAGB, 26 were female (70%), mean age at LSG and at conversion was 38.8 ± 11.75 years (range 14–59) and 46 ± 12.75 years (range 20–66 years), respectively (Table 1). Median time interval between LSG and conversion to OAGB was 7 years (range 1–14) and median follow-up time was 21.5 months (range 3–65). Mean BMI pre-LSG, pre-OAGB and post-OAGB nadir were 44.2 (range 35-61.7) kg/m2, 38.9 (23.2–48.3) kg/m2and 29.7 (18.4– 39.5) kg/m2, respectively (p < 0.0001, Table 1). Partial gastrectomy of enlarged sleeves was performed in Page 4/13 Page 4/13 all patients and the median afferent loop length was 230cm (range 200–360) from the ligament of Treitz to the gastro-jejunostomy. Three patients (10%) had a previous laparoscopic adjustable gastric band prior to their LSG. %TWL at post-LSG nadir was 33.9% (range 10–55%) and the %TWL at nadir weight following conversion was 33.3% (range 7%-56%). all patients and the median afferent loop length was 230cm (range 200–360) from the ligament of Treitz to the gastro-jejunostomy. Three patients (10%) had a previous laparoscopic adjustable gastric band prior to their LSG. %TWL at post-LSG nadir was 33.9% (range 10–55%) and the %TWL at nadir weight following conversion was 33.3% (range 7%-56%). following conversion was 33.3% (range 7%-56%). Results Table 1 Patients demographics, anthropometrics and co-morbidities Variable Pre-LSG Pre-OAGB Post-OAGB p value Age in years, mean (range) 39.7 (14–62) 47.81 (22–67) / / Gender   / / / Male, n (%) 11 (34.4%)       Female, n (%) 21 (65.6%)       BMI mean (range) 44.21 (34.06– 61.71) 38.89 (23.2– 48.3) 29.66 (18.4– 39.5) <  0.0001 TWL at nadir, % (range)   33.9% (10–55%) 33.3% (7%-56%) NS Excess weight in Kg 54.47 (25.28–99.9) 39.47 (-5.2-64.4) 12.71 (-20.4- 44.4) <  0.0001 Nadir weight in Kg / 82.28 (56–120) 83.73 (57–121) 0.78 Indication         Weight, n (%) 32 (100%) 28 (87.5%) / / Reflux, n (%)   9 (28.1%)     Comorbidity, n (%)         DM 7 (21.8%) 2 (6.2%) 4 (12.5%)   HTN 6 (18.8%) 6 (18.8%) 8 (25%)   Hyper-cholesterolemia 6 (18.8%) 8 (25%) 8(25%) NS Hyper TG 2 (6.3%) 4 (12.5%) 4 (12.5%)   Proteinuria 1 (3.1%) 1 (3.1%) 0   OSA 3 (9.4%) 1 (3.1%) 2 (6.3%)   Fatty liver 12 (37.5%) 11 (34.4%) 11 (34.4%)   LSG – Laparoscopic sleeve gastrectomy, OAGB – One-anastomosis gastric bypass, BMI – body mass index, DM – diabetes mellitus, HTN – hypertension, %TWL – percent total weight loss Table 1 LSG – Laparoscopic sleeve gastrectomy, OAGB – One-anastomosis gastric bypass, BMI – body mass index, DM – diabetes mellitus, HTN – hypertension, %TWL – percent total weight loss LSG – Laparoscopic sleeve gastrectomy, OAGB – One-anastomosis gastric bypass, BMI – body mass ndex, DM – diabetes mellitus, HTN – hypertension, %TWL – percent total weight loss Page 5/13 Pre-conversion EGD showed narrowing of the sleeve in 2 patients (6%), LA grade A esophagitis in 9 patients (28%), HH in 8 patients (25%) and 13 patients (40%) had an unremarkable exam. Pre-conversion UGI showed reflux of contrast in 9 patients (28%), a widened esophagus in 3 patients (9%), a HH in 10 patients (31%) and 18 patients (56%) had an unremarkable exam. There were no findings of Barrette’s dysplasia or malignancy in any of the patients. Table 2 represents the outcomes of the DRQ and GERD-HRQL scores at a median interval of 14 months (range 3–51) between pre- and post-OAGB. Median RDQ score pre-OAGB vs post-OAGB was significantly reduced [30 (range 12–72) vs 14 (range 12–60), p = 0.007]. Results All 3 parts of the GERD-HRQL questionnaires were significantly reduced between pre-OAGB and post-OAGB: Symptoms (20; 62.5% vs 10; 31.3%, p =  0.012), overall score [15(0–39) vs 7(0–28), p = 0.04] and subjective improvement [10; 31% vs 20; 62.5%, p  = 0.025). Table 2 Gastro-esophageal reflux disease questionnaires Variable Pre-OAGB Post-OAGB p value RDQ score (median) 30 (12–72) 14 (12–60) 0.007 GERD-HRQL score       Symptoms 20 (62.5%) 10 (31.3%) 0.012 Score 15 (0–39) 7 (0–28) 0.04 subjective 10 (31.3%) 20 (62.5%) 0.025 RDQ- reflux disease questionnaire, GERD-HRQL- gastro-esophageal reflux disease quality of life scale Table 2 Major perioperative complications (CD ≥ 3) occurred in 8 (25%) patients (Table 3). Complications requiring re-operation included 2 proximal staple line leaks from the partial gastrectomy which required laparoscopic lavage with drainage with one patient undergoing endoluminal stent placement. Further fluoroscopic studies confirmed leak resolution 4 weeks post-op for both patients with subsequent removal of drains and endoluminal stent. Dysphagia with reflux requiring conversion to RYGB occurred in 3 patients, 2 in the immediate post-operative course (POD 2 & 14), both for technical problems, one pouch stenosis and one anastomotic stenosis, and 1 within one year of conversion to OAGB. Complications beyond the 30-days post-op period included loose stools (n = 6, 19%) and marginal ulcers (n = 2, 6%) which were managed with oral PPI continuation. There were no conversions to “open” operations and no conversion related deaths. Page 6/13 Table 3 Post-operative complications   n = 32 CD ≥ 3 Total 16 (50%) 8 (25%) Diarrhea/loose stools 6 (19%) 0 Leakage 2 (6%) 2 (6%) Dysphagia 4 (12.5%) 2 (6%) Anastomosis ulcer 2 (6%) 2 (6%) CD- Clavien-Dindo classification score Table 3 Discussion LSG is the most popular bariatric operation in the world[1]. Although the majority of patients undergoing LSG achieve adequate weight loss without concomitant complications, a substantial amount of patients undergo secondary operations [8, 22]. As LSG is extensively utilized, bariatric surgeons worldwide are frequently encountered with patients requiring revision of their LSG, with several options for conversions available. Nonetheless, specific guidelines for conversion of LSG for any indication are lacking. OAGB is a prominent primary and revisional bariatric operation that is under scrutiny for inducing GERD and bile reflux [17, 18]. Our study examines whether revising LSG to OAGB induces or worsens GERD by assessing patients’ subjective GERD complaints by 2 validated clinical questionnaires. Population of our study was composed of predominantly morbidly obese, adult women with a median time interval between LSG and conversion of 7 years and a short to medium median follow up time of 21 months. Our results show a significant improvement of reflux symptoms in both the RDQ (p = 0.007) and GERD-HRQL (p = 0.012, p =  0.04 and p = 0.025; Table 2) while adding and maintaining adequate weight-loss (mean %TWL 33%). As expected for revisional bariatric operations, the peri-operative major complications (CD ≥ 3) rate was high (n = 8, 25%) with 2 (6%) patients undergoing early reoperations for conversion to RYGB. We believe that happened due to overly tight trimming of the enlarged sleeve which may have been avoided by abstaining from resizing. The link between morbid obesity, LSG and GERD has multiple proposed mechanisms that include a hypotensive lower esophageal sphincter, decreased gastric emptying, increase in intraluminal gastric pressure, hiatal hernia (HH) presence and angle of His anatomy disruption [9, 23–27]. Several long term (> 5 years) post-LSG studies weigh on the impact of de-novo GERD following LSG. Kowalewski et al. have reported that 93% of post-LSG patients develop de-novo GERD in over 8 years of follow-up, without any correlation between weight loss and reflux development [10]. Himpens et al. have documented that post- LSG GERD is evident in 20% of patients and have postulated that post-LSG GERD occurs in the setting of a neo-fundus formation, secondary to mid-stomach stenosis, which in turn causes stasis of food and Page 7/13 increased acid production. The authors showed increased GERD frequency at 6 years vs. 3 years post- LSG, which suggests a delayed development of post-LSG GERD [28]. Discussion For decades, RYGB was considered the optimal operative management for GERD [29]. A recent large (n =  2454) Swedish nationwide cohort study by Holmberg et al. assessed the long-term impact of GERD by chronic use of PPI and showed a 48% recurrence of GERD symptoms in 10 years following RYGB [30]. Nevertheless, the optimal operation for GERD resolution has yet to be determined and many patients rely on life-long PPI use. Landreneau et al., Yorke et al. and Parmar et al. have all reported on conversions of LSG to RYGB for the surgical treatment of post-LSG GERD for patients refractory to medical therapy, with effective treatment and resolution of GERD in over 70% in all series [31–33]. Weight-regain and de-novo GERD following LSG are closely linked. As conversion to RYGB may resolve GERD symptoms, its effectiveness as a revisional bariatric operation for weight-regain following LSG is limited. On the other hand, revision to OAGB following a failed LSG induces a more efficient weight-loss compared to RYGB [8]. If OAGB resolves or improves GERD symptoms, it may turn out to be the optimal conversion option for post-LSG patients suffering from both weight regain and GERD. Though OAGB is increasingly utilized worldwide as a primary bariatric operation with respectable outcomes, its safety for both primary and as a revisional procedure is still debated. Several publications postulate that OAGB by itself can induce GERD and unsurprisingly, OAGB has been under scrutiny for inducing GERD, bile reflux and their sequelae. Furthermore, there is a concern that patients undergoing OAGB are at an increased risk of developing erosive esophagitis, esophageal carcinoma and gastric stump cancer [34]. As the potential biliary reflux induced by OAGB may stimulate esophageal metaplasia, converting LSG with de- novo GERD may further contribute to increased risk of carcinogenesis. In a systemic review of the literature, Georgiadou et al. have found that bile reflux and esophagitis are rare events following OAGB that occur at rates of 0–2% [35]. Similarly, in a comparison between RYGB and OAGB, Lee WJ et al. reported no significant difference in clinical symptoms of bile reflux following either procedure [14]. Kassir et al. reported on 2780 OAGB patients with a 1.2% (n = 32) rate of biliary reflux occurrence requiring revision to RYGB at 30 months follow up with 75% of them having a previous LSG prior to OAGB. Discussion Conversely, other publications document higher rates of bile reflux following OAGB. A randomized control trial of 40 patients by Saarinen et al., utilizing EGD and bile reflux scintigraphy at 6 months following primary OAGB showed 2.6% (1 patient) with esophageal bile reflux and 31.6% (12 patients) had bile reflux in their gastric pouch. Keleidari et al., reviewed 5 cohort studies with a wide range of biliary reflux incidence of 7.8–55%. As for factors increasing the frequency of GERD following OAGB, a multi-institutional survey of 2678 patients with 5 Years of follow-up by Musella et al. showed that GERD following primary OAGB is significantly higher in patients with gastric pouch length of less than 9cm [36]. Additionally, in a long-term follow-up of more than 6 years of 1200 primary OAGB procedures, Carbajo et al. have shown that 53% (n  = 636) of their cohort had pre-operative GERD which resolved in 92% and improved in 8% following OAGB [37]. Conversely, in a long-term follow up of over 10 years of 385 patients undergoing a OAGB by Page 8/13 Caradina et al., biliary reflux was reported in 9.8% with the majority of them having a previous banding operation and 5.7% suffered from intractable reflux which required further conversion to RYGB[38]. Though the majority of our cohort benefited from conversion of LSG to OAGB with significant improvement of subjective symptoms, 3 patients (9%) suffered from intractable reflux symptoms and required further revision to RYGB, 2 in the immediate post-op period and 1 in the year following conversion to OAGB. Chevallier et al.[39] and Musela et al.[36] showed an OAGB to RYGB conversion rate of 0.9% (9 of 1000 cases) and 2.5% (28 of 1091 cases), respectively, both at 5 years of follow up. Conversely, Winstanely et al.[40] reported a 14% conversion rate(n = 5/34) in patients suffering from preoperative GERD at a median interval of 16 months. Whereas our results fall somewhat in the range of these conversion rates, future reflux recurrence may be inevitable and longer follow up is needed to estimate the true rate of further conversion to RYGB. It is still unclear and thus challenging to predict which patients will suffer exacerbation of reflux symptoms following conversion to OAGB. Our study shows that OAGB can be safely performed for failed LSG, with an acceptable subjective post-conversion GERD rate along with improvement of subjective GERD symptoms in a short-term follow up. Author Contribution: DA- Statistical and data analysis AK- Study conception and design, interpretation of data and critical revision of manuscript. Discussion However, a careful review of the pre-operative EGD and UGI is necessary, in order to tailor patient-directed treatment and decrease the chances of post-conversion GERD and thus decrease the need for further revision to RYGB. Furthermore, we advocate the formation of a long and narrow gastric pouch to prevent GERD symptoms following conversion to OAGB. The benefits and shortcomings of sleeve re-sizing in revisional bariatric surgery are uncertain. The desire to reinstate further weight loss led us to resize the sleeve, and in two patients it caused complication of immediate postoperative dysphagia, which required an anastomosis resection with subsequent conversion to RYGB. Although we believe that a smaller and narrower pouch in OAGB has reflux- protective properties and promotes further weight loss, this purported benefit must be balanced with constructing a too narrow pouch and stricture. As malabsorption has a substantial contribution to weight- loss in OAGB, trimming of the gastric sleeve may be unnecessary in any circumstances. Furthermore, as the malabsorptive properties of OAGB may potentially lead to severe malnutrition, determining the afferent limb length for individual patients is essential, as well as careful post-operative nutritional assessment. Our study has several limitations, as the majority of subjects underwent their primary LSG at outside hospitals with various pre-operative evaluation, surgical technique and post-operative care. Furthermore, the diagnosis and improvement of GERD was made by clinical symptoms, pre-conversion EGD findings, PPI use and the aforementioned questionnaires, without pH studies or post-conversion EGD. Findings of biliary reflux were absent which may reflect our small population size and short-term follow up. There are also multiple patients which had a previous bariatric operation (banding) prior to their LSG and patients who underwent conversion due to different indications, which may confound our findings. Despite these limitations, our study deals with daily situations of patients resorting to a secondary operation following Page 9/13 LSG. It is also a viable addition to the literature regarding GERD following OAGB and following conversion of LSG to OAGB. Conclusion OAGB does not induce or worsens subjective GERD in patients with a previous LSG on a short term. OAGB does not induce or worsens subjective GERD in patients with a previous LSG on a short term. Author disclosure: All authors have no conflict of interest or financial ties to disclose, relevant for this paper. References 1. Welbourn R, Hollyman M, Kinsman R, et al (2019) Bariatric Surgery Worldwide: Baseline Demographic Description and One-Year Outcomes from the Fourth IFSO Global Registry Report 2018. Obes Surg 29:782–795. https://doi.org/10.1007/s11695-018-3593-1 1. Welbourn R, Hollyman M, Kinsman R, et al (2019) Bariatric Surgery Worldwide: Baseline Demographic Description and One-Year Outcomes from the Fourth IFSO Global Registry Report 2018. Obes Surg 29:782–795. https://doi.org/10.1007/s11695-018-3593-1 2. Altieri MS, Yang J, Nie L, et al (2018) Rate of revisions or conversion after bariatric surgery over 10 years in the state of New York. Surgery for Obesity and Related Diseases 14:500–507. https://doi.org/10.1016/j.soard.2017.12.019 3. Lazzati A, Bechet S, Jouma S, et al (2020) Revision surgery after sleeve gastrectomy: a nationwide study with 10 years of follow-up. Surgery for Obesity and Related Diseases 16:1497–1504. https://doi.org/10.1016/j.soard.2020.05.021 Page 10/13 Page 10/13 4. Clapp B, Wynn M, Martyn C, et al (2018) Long term (7 or more years) outcomes of the sleeve gastrectomy: a meta-analysis. Surgery for Obesity and Related Diseases 14:741–747. https://doi.org/10.1016/j.soard.2018.02.027 5. Iannelli A, Debs T, Martini F, et al (2016) Laparoscopic conversion of sleeve gastrectomy to Roux-en-Y gastric bypass: indications and preliminary results. Surgery for Obesity and Related Diseases 12:1533–1538. https://doi.org/10.1016/j.soard.2016.04.008 5. Iannelli A, Debs T, Martini F, et al (2016) Laparoscopic conversion of sleeve gastrectomy to Roux-en-Y gastric bypass: indications and preliminary results. Surgery for Obesity and Related Diseases 12:1533–1538. https://doi.org/10.1016/j.soard.2016.04.008 6. Homan J, Betzel B, Aarts EO, et al (2015) Secondary surgery after sleeve gastrectomy: Roux-en-Y gastric bypass or biliopancreatic diversion with duodenal switch. Surgery for Obesity and Related Diseases 11:771–777. https://doi.org/10.1016/j.soard.2014.09.029 6. Homan J, Betzel B, Aarts EO, et al (2015) Secondary surgery after sleeve gastrectomy: Roux-en-Y gastric bypass or biliopancreatic diversion with duodenal switch. Surgery for Obesity and Related Diseases 11:771–777. https://doi.org/10.1016/j.soard.2014.09.029 7. Langer FB, Bohdjalian A, Shakeri-Leidenmühler S, et al (2010) Conversion from sleeve gastrectomy to roux-en-y gastric bypass-indications and outcome. Obes Surg 20:835–840. https://doi.org/10.1007/s11695-010-0125-z 7. Langer FB, Bohdjalian A, Shakeri-Leidenmühler S, et al (2010) Conversion from sleeve gastrectomy to roux-en-y gastric bypass-indications and outcome. Obes Surg 20:835–840. https://doi.org/10.1007/s11695-010-0125-z 8. Rayman S, Assaf D, Azran C, et al (2021) Sleeve Gastrectomy Failure—Revision to Laparoscopic One- Anastomosis Gastric Bypass or Roux-n-Y Gastric Bypass: a Multicenter Study. Obes Surg 3–10. https://doi.org/10.1007/s11695-021-05334-9 8. Rayman S, Assaf D, Azran C, et al (2021) Sleeve Gastrectomy Failure—Revision to Laparoscopic One- Anastomosis Gastric Bypass or Roux-n-Y Gastric Bypass: a Multicenter Study. Obes Surg 3–10. https://doi.org/10.1007/s11695-021-05334-9 9. References Laffin M, Chau J, Gill RS, et al (2013) Sleeve gastrectomy and gastroesophageal reflux disease. J Obes 2013:. https://doi.org/10.1155/2013/741097 9. Laffin M, Chau J, Gill RS, et al (2013) Sleeve gastrectomy and gastroesophageal reflux disease. J Obes 2013:. https://doi.org/10.1155/2013/741097 10. Kowalewski PK, Olszewski R, Walędziak MS, et al (2018) Long-Term Outcomes of Laparoscopic Sleeve Gastrectomy—a Single-Center, Retrospective Study. Obes Surg 28:130–134. https://doi.org/10.1007/s11695-017-2795-2 10. Kowalewski PK, Olszewski R, Walędziak MS, et al (2018) Long-Term Outcomes of Laparoscopic Sleeve Gastrectomy—a Single-Center, Retrospective Study. Obes Surg 28:130–134. https://doi.org/10.1007/s11695-017-2795-2 11. Mandeville Y, Van Looveren R, Vancoillie PJ, et al (2017) Moderating the Enthusiasm of Sleeve Gastrectomy: Up to Fifty Percent of Reflux Symptoms After Ten Years in a Consecutive Series of One Hundred Laparoscopic Sleeve Gastrectomies. Obes Surg 27:1797–1803. https://doi.org/10.1007/s11695-017-2567-z 11. Mandeville Y, Van Looveren R, Vancoillie PJ, et al (2017) Moderating the Enthusiasm of Sleeve Gastrectomy: Up to Fifty Percent of Reflux Symptoms After Ten Years in a Consecutive Series of One Hundred Laparoscopic Sleeve Gastrectomies. Obes Surg 27:1797–1803. https://doi.org/10.1007/s11695-017-2567-z 12. Rutledge R (2001) The mini-gastric bypass: Experience with the first 1,274 cases. Obes Surg 11:276– 280. https://doi.org/10.1381/096089201321336584 12. Rutledge R (2001) The mini-gastric bypass: Experience with the first 1,274 cases. Obes Surg 11:276– 280. https://doi.org/10.1381/096089201321336584 13. Parmar CD, Bryant C, Luque-de-Leon E, et al (2019) One Anastomosis Gastric Bypass in Morbidly Obese Patients with BMI ≥ 50 kg/m2: a Systematic Review Comparing It with Roux-En-Y Gastric Bypass and Sleeve Gastrectomy. Obes Surg 29:3039–3046. https://doi.org/10.1007/s11695-019- 04034-9 14. Lee WJ, Almalki OM, Ser KH, et al (2019) Randomized Controlled Trial of One Anastomosis Gastric Bypass Versus Roux-En-Y Gastric Bypass for Obesity: Comparison of the YOMEGA and Taiwan Studies. Obes Surg 29:3047–3053. https://doi.org/10.1007/s11695-019-04065-2 15. Jamal W, Zagzoog MM, Sait SH, et al (2019) Initial outcomes of one anastomosis gastric bypass at a single institution. Diabetes Metab Syndr Obes 12:35–41. https://doi.org/10.2147/DMSO.S180111 15. Jamal W, Zagzoog MM, Sait SH, et al (2019) Initial outcomes of one anastomosis gastric bypass at a single institution. Diabetes Metab Syndr Obes 12:35–41. https://doi.org/10.2147/DMSO.S180111 16. Moszkowicz D, Rau C, Guenzi M, et al (2013) Laparoscopic omega-loop gastric bypass for the conversion of failed sleeve gastrectomy: early experience. J Visc Surg 150:373–378. https://doi.org/10.1016/j.jviscsurg.2013.08.010 Page 11/13 Page 11/13 17. Bruzzi M, Chevallier JM, Czernichow S (2017) One-Anastomosis Gastric Bypass: Why Biliary Reflux Remains Controversial? Obes Surg 27:545–547. https://doi.org/10.1007/s11695-016-2480-x 18. References Mahawar KK, Borg CM, Kular KS, et al (2017) Understanding Objections to One Anastomosis (Mini) Gastric Bypass: A Survey of 417 Surgeons Not Performing this Procedure. Obes Surg 27:2222–2228. https://doi.org/10.1007/s11695-017-2663-0 19. Shaw M, Dent J, Beebe T, et al (2008) The reflux disease questionnaire: A measure for assessment of treatment response in clinical trials. Health Qual Life Outcomes 6:1–6. https://doi.org/10.1186/1477-7525-6-31 20. Velanovich V (1998) Comparison of generic (SF-36) vs. disease-specific (GERD-HRQL) quality-of-life scales for gastroesophageal reflux disease. J Gastrointest Surg 2:141–145. https://doi.org/10.1016/s1091-255x(98)80004-8 21. Clavien PA, Barkun J, de Oliveira ML, et al (2009) The clavien-dindo classification of surgical complications: Five-year experience. Ann Surg 250:187–196. https://doi.org/10.1097/SLA.0b013e3181b13ca2 22. Clapp B, Wynn M, Martyn C, et al (2018) Long term (7 or more years) outcomes of the sleeve gastrectomy: a meta-analysis. Surgery for Obesity and Related Diseases 14:741–747. https://doi.org/10.1016/j.soard.2018.02.027 23. Yehoshua RT, Eidelman LA, Stein M, et al (2008) Laparoscopic Sleeve gastrectomy - Volume and pressure assessment. Obes Surg 18:1083–1088. https://doi.org/10.1007/s11695-008-9576-x 24. Braghetto I, Lanzarini E, Korn O, et al (2010) Manometric changes of the lower esophageal sphincter after sleeve gastrectomy in obese patients. Obes Surg 20:357–362. https://doi.org/10.1007/s11695- 009-0040-3 25. Himpens J, Dapri G, Cadière GB (2006) A prospective randomized study between laparoscopic gastric banding and laparoscopic isolated sleeve gastrectomy: Results after 1 and 3 years. Obes Surg 16:1450–1456. https://doi.org/10.1381/096089206778869933 26. Chiu S, Birch DW, Shi X, et al (2011) Effect of sleeve gastrectomy on gastroesophageal reflux disease: A systematic review. Surgery for Obesity and Related Diseases 7:510–515. https://doi.org/10.1016/j.soard.2010.09.011 27. Del Genio G, Tolone S, Limongelli P, et al (2014) Sleeve gastrectomy and development of “de novo” gastroesophageal reflux. Obes Surg 24:71–77. https://doi.org/10.1007/s11695-013-1046-4 gastroesophageal reflux. Obes Surg 24:71–77. https://doi.org/10.1007/s11695-013-1046-4 28. Himpens J, Dobbeleir J, Peeters G (2010) Long-term results of laparoscopic sleeve gastrectomy for obesity. Ann Surg 252:319–324. https://doi.org/10.1097/SLA.0b013e3181e90b31 28. Himpens J, Dobbeleir J, Peeters G (2010) Long-term results of laparoscopic sleeve gastrectomy for obesity. Ann Surg 252:319–324. https://doi.org/10.1097/SLA.0b013e3181e90b31 29. Adil MT, Al-taan O, Rashid F, et al (2019) A Systematic Review and Meta-Analysis of the Effect of Roux-en-Y Gastric Bypass on Barrett’s Esophagus. Obes Surg 29:3712–3721. https://doi.org/10.1007/s11695-019-04083-0 29. Adil MT, Al-taan O, Rashid F, et al (2019) A Systematic Review and Meta-Analysis of the Effect of Roux-en-Y Gastric Bypass on Barrett’s Esophagus. Obes Surg 29:3712–3721. https://doi.org/10.1007/s11695-019-04083-0 30. Holmberg D, Santoni G, Xie S, Lagergren J (2019) Gastric bypass surgery in the treatment of gastro- oesophageal reflux symptoms. Aliment Pharmacol Ther 50:159–166. References https://doi.org/10.1111/apt.15274 30. Holmberg D, Santoni G, Xie S, Lagergren J (2019) Gastric bypass surgery in the treatment of gastro- oesophageal reflux symptoms. Aliment Pharmacol Ther 50:159–166. https://doi.org/10.1111/apt.15274 Page 12/13 Page 12/13 31. Yorke E, Sheppard C, Switzer NJ, et al (2017) Revision of sleeve gastrectomy to Roux-en-Y Gastric Bypass: A Canadian experience. Am J Surg 213:970–974. https://doi.org/10.1016/j.amjsurg.2017.04.003 32. Parmar CD, Mahawar KK, Boyle M, et al (2017) Conversion of Sleeve Gastrectomy to Roux-en-Y Gastric Bypass is Effective for Gastro-Oesophageal Reflux Disease but not for Further Weight Loss. Obes Surg 27:1651–1658. https://doi.org/10.1007/s11695-017-2542-8 33. Landreneau JP, Strong AT, Rodriguez JH, et al (2018) Conversion of Sleeve Gastrectomy to Roux-en-Y Gastric Bypass. Obes Surg 28:3843–3850. https://doi.org/10.1007/s11695-018-3435-1 33. Landreneau JP, Strong AT, Rodriguez JH, et al (2018) Conversion of Sleeve Gastrectomy to Roux-en-Y Gastric Bypass. Obes Surg 28:3843–3850. https://doi.org/10.1007/s11695-018-3435-1 34. Schafer LW, Larson DE, Melton LJ 3rd, et al (1983) The risk of gastric carcinoma after surgical treatment for benign ulcer disease. A population-based study in Olmsted County, Minnesota. N Engl J Med 309:1210–1213. https://doi.org/10.1056/NEJM198311173092003 35. Georgiadou D, Sergentanis TN, Nixon A, et al (2014) Efficacy and safety of laparoscopic mini gastric bypass. A systematic review. Surgery for Obesity and Related Diseases 10:984–991. https://doi.org/10.1016/j.soard.2014.02.009 35. Georgiadou D, Sergentanis TN, Nixon A, et al (2014) Efficacy and safety of laparoscopic mini gastric bypass. A systematic review. Surgery for Obesity and Related Diseases 10:984–991. https://doi.org/10.1016/j.soard.2014.02.009 36. Musella M, Susa A, Manno E, et al (2017) Complications Following the Mini/One Anastomosis Gastric Bypass (MGB/OAGB): a Multi-institutional Survey on 2678 Patients with a Mid-term (5 Years) Follow-up. Obes Surg 27:2956–2967. https://doi.org/10.1007/s11695-017-2726-2 36. Musella M, Susa A, Manno E, et al (2017) Complications Following the Mini/One Anastomosis Gastric Bypass (MGB/OAGB): a Multi-institutional Survey on 2678 Patients with a Mid-term (5 Years) Follow-up. Obes Surg 27:2956–2967. https://doi.org/10.1007/s11695-017-2726-2 37. Carbajo MA, Luque-de-León E, Jiménez JM, et al (2017) Laparoscopic One-Anastomosis Gastric Bypass: Technique, Results, and Long-Term Follow-Up in 1200 Patients. Obes Surg 27:1153–1167. https://doi.org/10.1007/s11695-016-2428-1 37. Carbajo MA, Luque-de-León E, Jiménez JM, et al (2017) Laparoscopic One-Anastomosis Gastric Bypass: Technique, Results, and Long-Term Follow-Up in 1200 Patients. Obes Surg 27:1153–1167. https://doi.org/10.1007/s11695-016-2428-1 38. Carandina S (2021) Long-Term Results of One Anastomosis Gastric Bypass: a Single Center Experience with a Minimum Follow-Up of 10 Years. 3468–3475 38. Carandina S (2021) Long-Term Results of One Anastomosis Gastric Bypass: a Single Center Experience with a Minimum Follow-Up of 10 Years. 3468–3475 39. References Chevallier JM, Arman GA, Guenzi M, et al (2015) One Thousand Single Anastomosis (Omega Loop) Gastric Bypasses to Treat Morbid Obesity in a 7-Year Period: Outcomes Show Few Complications and Good Efficacy. Obes Surg 25:951–958. https://doi.org/10.1007/s11695-014-1552-z 39. Chevallier JM, Arman GA, Guenzi M, et al (2015) One Thousand Single Anastomosis (Omega Loop) Gastric Bypasses to Treat Morbid Obesity in a 7-Year Period: Outcomes Show Few Complications and Good Efficacy. Obes Surg 25:951–958. https://doi.org/10.1007/s11695-014-1552-z 40. Winstanley J, Ahmed S, Courtney M, et al (2021) One Anastomosis Gastric Bypass in Patients with Gastrooesophageal Reflux Disease and/or Hiatus Hernia. Obes Surg 31:1449–1454. https://doi.org/10.1007/s11695-020-05149-0 40. Winstanley J, Ahmed S, Courtney M, et al (2021) One Anastomosis Gastric Bypass in Patients with Gastrooesophageal Reflux Disease and/or Hiatus Hernia. Obes Surg 31:1449–1454. https://doi.org/10.1007/s11695-020-05149-0 Page 13/13
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Conjugation of the 9-kDa Isoform of Granulysin with Liposomes Potentiates Its Cytotoxicity
International journal of molecular sciences
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Citation: Soler-Agesta, R.; Guerrero-Ochoa, P.; Marco-Brualla, J.; Ibáñez-Pérez, R.; Marzo, I.; Martínez-Lostao, L.; Anel, A. Conjugation of the 9-kDa Isoform of Granulysin with Liposomes Potentiates Its Cytotoxicity. Int. J. Mol. Sci. 2022, 23, 8705. https:// doi.org/10.3390/ijms23158705 Academic Editor: Christian Celia Received: 13 July 2022 Accepted: 3 August 2022 Published: 5 August 2022 Citation: Soler-Agesta, R.; Guerrero-Ochoa, P.; Marco-Brualla, J.; Ibáñez-Pérez, R.; Marzo, I.; Martínez-Lostao, L.; Anel, A. Conjugation of the 9-kDa Isoform of Granulysin with Liposomes Potentiates Its Cytotoxicity. Int. J. Mol. Sci. 2022, 23, 8705. https:// doi.org/10.3390/ijms23158705 Keywords: granulysin; lipid nanoparticles; acute lymphoid leukemia; apoptosis; immunotherapy Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. International Journal of Molecular Sciences International Journal of Molecular Sciences International Journal of Molecular Sciences International Journal of Molecular Sciences Article Ruth Soler-Agesta 1, Patricia Guerrero-Ochoa 1 , Joaquín Marco-Brualla 1 , Raquel Ibáñez-Pérez 1, Isabel Marzo 1 , Luis Martínez-Lostao 2,3 and Alberto Anel 1,* Ruth Soler-Agesta 1, Patricia Guerrero-Ochoa 1 , Joaquín Marco-Brualla 1 , Raquel Ibáñez-Pérez 1 Isabel Marzo 1 , Luis Martínez-Lostao 2,3 and Alberto Anel 1,* 1 Apoptosis, Immunity & Cancer Group, Department of Biochemistry and Molecular and Cell Biology, Faculty of Sciences, Aragón Health Research Institute (IIS Aragón), University of Zaragoza, 50009 Zaragoza, Spain Nanoscience Institute of Aragon (INA), 50018 Zaragoza, Spain 3 Immunology Department, Clinical University Hospital “Lozano Blesa”, 50009 Zaragoza, Spain * C d l@ i * Correspondence: anel@unizar.es Abstract: Nine kDa granulysin (GRNLY) is a human cytolytic protein secreted by cytotoxic T lym- phocytes (CTL) and NK cells of the immune system whose demonstrated physiological function is the elimination of bacteria and parasites. In previous studies by our group, the anti-tumor capacity of recombinant granulysin was demonstrated, both in vitro and in vivo. In the present work, we developed lipid nanoparticles whose surfaces can bind recombinant granulysin through the forma- tion of a complex of coordination between the histidine tail of the protein and Ni2+ provided by a chelating lipid in the liposome composition and termed them LUV-GRNLY, for granulysin-bound large unilamellar vesicles. The objective of this formulation is to increase the granulysin concen- tration at the site of contact with the target cell and to increase the cytotoxicity of the administered dose. The results obtained in this work indicate that recombinant granulysin binds to the surface of the liposome with high efficiency and that its cytotoxicity is significantly increased when it is in association with liposomes. In addition, it has been demonstrated that the main mechanism of death induced by both granulysin and LUV-GRNLY is apoptosis. Jurkat-shBak cells are resistant to GRNLY and also to LUV-GRNLY, showing that LUV-GRNLY uses the mitochondrial apoptotic pathway to induce cell death. On the other hand, we show that LUV-GRNLY induces the expression of the pro-apoptotic members of the Bcl-2 family Bim and especially PUMA, although it also induced the expression of anti-apoptotic Bcl-xL. In conclusion, we demonstrate that binding of GRNLY to the surfaces of liposomes clearly augments its cytotoxic potential, with cell death executed mainly by the mitochondrial apoptotic pathway. 1. Introduction Granulysin (GRNLY) is a protein with two isoforms of 9 and 15 kDa molecular weight, respectively. The 9 kDa isoform is a cytolytic protein present in the granules of activated human cytotoxic T lymphocytes (CTL) and natural killer (NK) cells, while the 15 kDa isoform is rather an immune alarmin [1–3]. The antibacterial and antiparasitic functions of 9 kDa GRNLY have long been known, and they have been confirmed and expanded in recent studies [4–6]. We have shown previously that recombinant GRNLY is able to kill tumor cells in vitro using the mitochondrial apoptotic pathway [7–9]. On the other hand, there are abundant data that relate granulysin expression to an active antitumor immune response and to patient good prognosis [10–13]. Although mice do not express a granulysin homologue, transgenic mice that expressed human granulysin were generated, showing increased resistance to tumor development [14]. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). https://www.mdpi.com/journal/ijms Int. J. Mol. Sci. 2022, 23, 8705. https://doi.org/10.3390/ijms23158705 2 of 13 Int. J. Mol. Sci. 2022, 23, 8705 More recently, we demonstrated the efficacy of recombinant GRNLY in three xeno- transplantation models of human tumors in athymic mice, the mammary adenocarcinoma MDA-MB-231, the multiple myeloma NCI-H929 and the melanoma UACC62 [15,16]. The intra-tumor administration of GRNLY in these models correlated with apoptosis induction in the tumor tissue and with prominent NK cell infiltration into the tumor mass, indicat- ing that granulysin-induced tumor cell death in vivo could be immunogenic [15,16]. In an effort to target recombinant GRNLY specifically to tumors, we developed an immuno- toxin by GRNLY gene fusion to the anti- carcinoembryonic antigen (CEA/CEACAM5) single chain Fv antibody fragment MFE23. Systemic administration of the immunotoxin demonstrated a decrease in tumor growth in a CEA+ tumor-bearing mouse model, whereas GRNLY did not exhibit a therapeutic effect [17]. Other GRNLY-based immunotoxins di- rected against the MUC1-Tn tumor antigen have been applied, demonstrating in vitro and in vivo efficacy in pre-clinical models [18,19]. These immunotoxins could have a broader application to different solid tumors and leukemia than the anti-CEA immunotoxin [20]. Considering the perspective of the therapeutic use of GRNLY in a broader spectrum of cancers, it is important to develop strategies that allow its systemic administration. 1. Introduction This will require vehicles that increase GRNLY ability to access the tumor while preserving or increasing its bioactivity. In previous experiences using large unilamellar vesicles (LUVs), a drug delivery vehicle that consists of a phospholipid bilayer containing an inner, aque- ous pocket [21], our group demonstrated greater cytotoxicity against tumors using LUV conjugated with TNF-related apoptosis-inducing ligand (TRAIL) compared with TRAIL in soluble phase [22–24]. We also demonstrated both in vitro and in vivo that this anti-tumor effect was increased if doxorubicin was encapsulated in the TRAIL-decorated LUVs [25]. In the present study, we generated LUV conjugated with GRNLY (LUV-GRNLY) and tested its antitumor efficacy and mechanism of tumor cell death induction. Results demonstrate that our hypothesis of a possible increase in GRNLY cytotoxicity by binding to liposomes was correct, and offer new perspectives for this novel cytotoxic formulation based on a human protein. GRNLY Binds Efficiently to LUV Surface through the DOGS-NTA-Ni Lipid . GRNLY Binds Efficiently to LUV Surface through the DOGS-NTA-Ni Lipid In order to optimize the binding of GRNLY-His6 to DOGS-NTA-Ni in the liposom everal concentrations of granulysin, between 4 and 30 μM, were incubated with lipo omes, ultracentrifugated, and pellet and supernatant collected separately. The presenc of the recombinant protein in each fraction was assessed by Western blot using an ant body against the histidine-tag motif. As shown in Figure 1B, from 4 to 10 μM, all of th ecombinant protein was found only in the pellet fraction, indicating that all of the protei was bound to the liposome surfaces. Nevertheless, at 15 μM, a small portion of the protei emained free in the supernatant, indicating that the surfaces of the liposomes began t be saturated. Finally, at 30 μM, a significant protein band appeared in the supernatan raction, showing the full saturation of the liposome surface. In the following experiment he stock of LUV GRNLY was prepared with a 15 μM concentration of recombinan In order to optimize the binding of GRNLY-His6 to DOGS-NTA-Ni in the liposome, several concentrations of granulysin, between 4 and 30 µM, were incubated with liposomes, ultracentrifugated, and pellet and supernatant collected separately. The presence of the recombinant protein in each fraction was assessed by Western blot using an antibody against the histidine-tag motif. As shown in Figure 1B, from 4 to 10 µM, all of the recombinant protein was found only in the pellet fraction, indicating that all of the protein was bound to the liposome surfaces. Nevertheless, at 15 µM, a small portion of the protein remained free in the supernatant, indicating that the surfaces of the liposomes began to be saturated. Finally, at 30 µM, a significant protein band appeared in the supernatant fraction, showing the full saturation of the liposome surface. In the following experiments, the stock of LUV-GRNLY was prepared with a 15 µM concentration of recombinant GRNLY. he stock of LUV-GRNLY was prepared with a 15 μM concentration of recombinan GRNLY. To confirm that the recombinant protein binds to the liposome surface through th ipid DOGS-NTA-Ni, increasing granulysin concentrations were incubated with LUV.0, variant liposome formulation without DOGS-NTA-Ni. As shown in Figure 1C, recomb nant granulysin was found mainly in the supernatant fractions for all tested concentra ions. 2. Results 2.1. Production and Purification of the Recombinant 9 kDa GRNLY in Pichia Pastoris As described in Materials and Methods, granulysin was subcloned into the pPICZαA vector for its production in Pichia pastoris. The recombinant protein was secreted in yeast culture supernatant and purified using a gravity-flow column containing an Ni+2- NTA resin. During the purification process, the presence of granulysin was controlled by recollecting samples in each step (concentrated, dialysis, resin washes, post-resin and post-amicon fractions) and resolved in an SDS-PAGE 15% polyacrylamide gel stained with Coomassie blue. The migration pattern of the dialysate fraction, as shown in Figure 1A, revealed several bands that correspond to a mixture of proteins produced by Pichia pastoris. Discarded fractions such as the permeate, the dialysis buffer and the resin washes showed that there was no loss of protein at the granulysin molecular weight. Finally, the migration pattern of post-resin and post-amicon fractions showed a single concentrated band that was consistent with the molecular weight of glycosylated recombinant granulysin produced in Pichia pastoris [17,26]. 3 of 13 3 of 1 Int. J. Mol. Sci. 2022, 23, 8705 . J. Mol. Sci. 2022, 23, x FOR P Figure 1. (A) Analysis of the purification process using SDS-PAGE polyacrylamide 15% gel staine with Coomassie blue. (B) Western-blot analysis of ultracentrifugated pellets (P) and supernatant (S fractions from LUV-GRNLY using an anti-His antibody. (C) Western blot of ultracentrifugated pe lets and supernatant fractions from LUV.0-GRNLY using an anti-His antibody. (D) Schematic rep resentation of the interaction between GRNLY-His6 and liposome surface through DOGS-NTA-N Figure 1. (A) Analysis of the purification process using SDS-PAGE polyacrylamide 15% gel stained with Coomassie blue. (B) Western-blot analysis of ultracentrifugated pellets (P) and supernatant (S) fractions from LUV-GRNLY using an anti-His antibody. (C) Western blot of ultracentrifugated pellets and supernatant fractions from LUV.0-GRNLY using an anti-His antibody. (D) Schematic representation of the interaction between GRNLY-His6 and liposome surface through DOGS-NTA-Ni. Figure 1. (A) Analysis of the purification process using SDS-PAGE polyacrylamide 15% gel staine with Coomassie blue. (B) Western-blot analysis of ultracentrifugated pellets (P) and supernatant ( ractions from LUV-GRNLY using an anti-His antibody. (C) Western blot of ultracentrifugated pe ets and supernatant fractions from LUV.0-GRNLY using an anti-His antibody. (D) Schematic rep esentation of the interaction between GRNLY-His6 and liposome surface through DOGS-NTA-N Figure 1. (A) Analysis of the purification process using SDS-PAGE polyacrylamide 15% gel stained with Coomassie blue. 2. Results (B) Western-blot analysis of ultracentrifugated pellets (P) and supernatant (S) fractions from LUV-GRNLY using an anti-His antibody. (C) Western blot of ultracentrifugated pellets and supernatant fractions from LUV.0-GRNLY using an anti-His antibody. (D) Schematic representation of the interaction between GRNLY-His6 and liposome surface through DOGS-NTA-Ni. .2. GRNLY Binds Efficiently to LUV Surface through the DOGS-NTA-Ni Lipid 2.2. GRNLY Binds Efficiently to LUV Surface through the DOGS-NTA-Ni Lipid GRNLY Binds Efficiently to LUV Surface through the DOGS-NTA-Ni Lipid . GRNLY Binds Efficiently to LUV Surface through the DOGS-NTA-Ni Lipid A small portion of the protein was also found in the pellet, showing that granulysi To confirm that the recombinant protein binds to the liposome surface through the lipid DOGS-NTA-Ni, increasing granulysin concentrations were incubated with LUV.0, a variant liposome formulation without DOGS-NTA-Ni. As shown in Figure 1C, recombinant granulysin was found mainly in the supernatant fractions for all tested concentrations. A small portion of the protein was also found in the pellet, showing that granulysin binds partially to the lipid membrane. A schematic representation of LUV-GRNLY once synthesized is shown in Figure 1D. Int. J. Mol. Sci. 2022, 23, 8705 Int. J. Mol. Sci. 2022, 23, x FOR 4 of 13 4 of 13 2.3. In Vitro Cytotoxic Effect of LUV-GRNLY on the Jurkat Cell Line We then determined the in vitro cytotoxicity of LUV-GRNLY lymphocytic leukemia cell line and compared it with soluble GRN We then determined the in vitro cytotoxicity of LUV-GRNLY against the Jurkat acute lymphocytic leukemia cell line and compared it with soluble GRNLY using flow cytometry. It has been described previously that soluble GRNLY is cytotoxic against Jurkat cells and that it is cytotoxic against a large panel of cancer cells [7,8]. We confirmed this observation in the dose–response assays shown in Figure 2A, showing an LC50 of around 10 µM, compatible with previous data using GRNLY produced in Pichia pastoris [17]. Besides that, as shown in Figure 2B, we demonstrated that LUV-GRNLY exhibited a higher cytotoxicity than GRNLY in soluble phase, reducing the LC50 by at least two-fold. In addition, the mortality rate of cells that were treated with liposomes alone was not significant compared to the control. Therefore, we concluded that the cytotoxicity of LUV-GRNLY is attributed to the formula by itself, discarding the possibility that liposomes could be toxic at this dose. lymphocytic leukemia cell line and compared it with soluble GRNLY using flow cytome try. It has been described previously that soluble GRNLY is cytotoxic against Jurkat cells and that it is cytotoxic against a large panel of cancer cells [7,8]. We confirmed this obser- vation in the dose–response assays shown in Figure 2A, showing an LC50 of around 10 μM, compatible with previous data using GRNLY produced in Pichia pastoris [17]. Be- sides that, as shown in Figure 2B, we demonstrated that LUV-GRNLY exhibited a higher cytotoxicity than GRNLY in soluble phase, reducing the LC50 by at least two-fold. GRNLY Binds Efficiently to LUV Surface through the DOGS-NTA-Ni Lipid . GRNLY Binds Efficiently to LUV Surface through the DOGS-NTA-Ni Lipid In ad- dition, the mortality rate of cells that were treated with liposomes alone was not signifi- cant compared to the control. Therefore, we concluded that the cytotoxicity of LUV- GRNLY is attributed to the formula by itself, discarding the possibility that liposomes could be toxic at this dose. Figure 2. In vitro cytotoxicity of GRNLY and LUV-GRNLY against Jurkat cell line. (A) Jurkat cells were incubated with increasing concentrations of GRNLY for 24 h. Cell death was determined by detection on phosphatidylserine exposure (PS) by staining with annexin-V-FITC using flow cytom- etry. (B) Jurkat cells were incubated with increasing concentrations of GRNLY and LUV-GRNLY (2.5, 5 and 7.5 μM) for 24 h, and cell death was determined by flow cytometry as previously de- scribed. The results are expressed as the mean ± SD of 3 independent experiments. *** p < 0.001. (C) Representative flow cytometry histograms corresponding to one of the experiments performed, showing the Annexin-V-FITC staining data (FL1-H channel) on Jurkat cells treated with control LUVs, with 7.5 μM GRNLY, or with 7.5 μM LUV-GRNLY, as indicated. 2 4 A l i f h M h i f C ll D h I d d b GRNLY d LUV GRNLY i J k Figure 2. In vitro cytotoxicity of GRNLY and LUV-GRNLY against Jurkat cell line. (A) Jurkat cells were incubated with increasing concentrations of GRNLY for 24 h. Cell death was determined by detection on phosphatidylserine exposure (PS) by staining with annexin-V-FITC using flow cytometry. (B) Jurkat cells were incubated with increasing concentrations of GRNLY and LUV-GRNLY (2.5, 5 and 7.5 µM) for 24 h, and cell death was determined by flow cytometry as previously described. The results are expressed as the mean ± SD of 3 independent experiments. *** p < 0.001. (C) Representative flow cytometry histograms corresponding to one of the experiments performed, showing the Annexin- V-FITC staining data (FL1-H channel) on Jurkat cells treated with control LUVs, with 7.5 µM GRNLY, or with 7.5 µM LUV-GRNLY, as indicated. Figure 2. In vitro cytotoxicity of GRNLY and LUV-GRNLY against Jurkat cell line. (A) Jurkat cells were incubated with increasing concentrations of GRNLY for 24 h. Cell death was determined by detection on phosphatidylserine exposure (PS) by staining with annexin-V-FITC using flow cytom- etry. GRNLY Binds Efficiently to LUV Surface through the DOGS-NTA-Ni Lipid . GRNLY Binds Efficiently to LUV Surface through the DOGS-NTA-Ni Lipid (B) Jurkat cells were incubated with increasing concentrations of GRNLY and LUV-GRNLY (2.5, 5 and 7.5 μM) for 24 h, and cell death was determined by flow cytometry as previously de- scribed. The results are expressed as the mean ± SD of 3 independent experiments. *** p < 0.001. (C) Representative flow cytometry histograms corresponding to one of the experiments performed, showing the Annexin-V-FITC staining data (FL1-H channel) on Jurkat cells treated with control LUVs, with 7.5 μM GRNLY, or with 7.5 μM LUV-GRNLY, as indicated. Figure 2. In vitro cytotoxicity of GRNLY and LUV-GRNLY against Jurkat cell line. (A) Jurkat cells were incubated with increasing concentrations of GRNLY for 24 h. Cell death was determined by detection on phosphatidylserine exposure (PS) by staining with annexin-V-FITC using flow cytometry. (B) Jurkat cells were incubated with increasing concentrations of GRNLY and LUV-GRNLY (2.5, 5 and 7.5 µM) for 24 h, and cell death was determined by flow cytometry as previously described. The results are expressed as the mean ± SD of 3 independent experiments. *** p < 0.001. (C) Representative flow cytometry histograms corresponding to one of the experiments performed, showing the Annexin- V-FITC staining data (FL1-H channel) on Jurkat cells treated with control LUVs, with 7.5 µM GRNLY, or with 7.5 µM LUV-GRNLY, as indicated. 2.4. Analysis of the Mechanism of Cell Death Induced by GRNLY and LUV-GRNLY in Jurkat Cells 2.4. Analysis of the Mechanism of Cell Death Induced by GRNLY and LUV-GRNLY in Jurkat Cells However, over-expression o he anti-apoptotic protein Bcl-xL in mutant cells provides protection against granulysin ut not against LUV-GRNLY (Figure 3C), suggesting that the LUV-GRNLY-induced cel eath signal is more powerful than that of GRNLY alone. Figure 3. Analysis of the mechanism of cell death induced by GRNLY and LUV-GRNLY. (A) Jurkat cells were treated with 7.5 μM of GRNLY or LUV-GRNLY for 24 h, respectively. Then, cells were simultaneously stained with annexin-V-FITC and 7-AAD and were analyzed using flow cytometry The dot-plots (upper, left panel) represent the evolution of treated cell population compared to the Figure 3. Analysis of the mechanism of cell death induced by GRNLY and LUV-GRNLY. (A) Jurkat cells were treated with 7.5 µM of GRNLY or LUV-GRNLY for 24 h, respectively. Then, cells were simultaneously stained with annexin-V-FITC and 7-AAD and were analyzed using flow cytometry. The dot-plots (upper, left panel) represent the evolution of treated cell population compared to the control. The values shown correspond to a percentage of cells in each quadrant. The upper right figure corresponds to a graphical representation of obtained data. Data shown are representative of four different experiments. (B,C) Jurkat and mutant cells (Jurkat-Bcl-xL, Jurkat-plvTHM and Jurkat-shBak) were treated with 7.5 µM of GRNLY or LUV-GRNLY, respectively, for 24 h. Cell death was determined by exposure of PS by staining with annexin-V-APC and analyzing by flow cytometry. The results are expressed as the mean ± SD of 3 independent experiments. *** p < 0.001. igure 3. Analysis of the mechanism of cell death induced by GRNLY and LUV-GRNLY. (A) Jurka ells were treated with 7.5 μM of GRNLY or LUV-GRNLY for 24 h, respectively. Then, cells wer imultaneously stained with annexin-V-FITC and 7-AAD and were analyzed using flow cytometry he dot-plots (upper, left panel) represent the evolution of treated cell population compared to th Figure 3. Analysis of the mechanism of cell death induced by GRNLY and LUV-GRNLY. (A) Jurkat cells were treated with 7.5 µM of GRNLY or LUV-GRNLY for 24 h, respectively. Then, cells were simultaneously stained with annexin-V-FITC and 7-AAD and were analyzed using flow cytometry. The dot-plots (upper, left panel) represent the evolution of treated cell population compared to the control. The values shown correspond to a percentage of cells in each quadrant. The upper right figure corresponds to a graphical representation of obtained data. Data shown are representative of four different experiments. 2.4. Analysis of the Mechanism of Cell Death Induced by GRNLY and LUV-GRNLY in Jurkat Cells 2.4. Analysis of the Mechanism of Cell Death Induced by GRNLY and LUV-GRNLY in Jurkat Cells Cells To further investigate the mechanism of cell death induced by GRNLY and LUV- GRNLY, we carried out flow cytometry experiments in which cells were stained at the same time with annexin-V and 7-AAD. The presence of a population of cells that were positive for annexin-V staining and still negative for 7-AAD staining was indicative of an apoptotic type of cell death, although at long times of in vitro exposure to toxic agents, To further investigate the mechanism of cell death induced by GRNLY and LUV- GRNLY, we carried out flow cytometry experiments in which cells were stained at the same time with annexin-V and 7-AAD. The presence of a population of cells that were positive for annexin-V staining and still negative for 7-AAD staining was indicative of an apoptotic type of cell death, although at long times of in vitro exposure to toxic agents, cells were found to be positive for both markers in a secondary necrosis process. The single positive population could be detected after treatment with 7.5 µM GRNLY for 24 h, constituting Int. J. Mol. Sci. 2022, 23, 8705 5 of 13 nd thus o the in 5 of 13 nd thus o the in 7% of the total population; at this time, the double positive population represented 15% (Figure 3A). This observation indicated the presence of an apoptotic type of cell death, in agreement with previous observations made with this cell line [7]. Cells treated with 7.5 µM LUV-GRNLY for 24 h showed the same staining characteristics: we observed again the single positive population (16% of the total population) and the double positive population (45%). Confirming data shown in Figure 2, the total percentage of cell death induced by LUV-GRNLY was higher (61.4% vs. 22.3%). Thus, we showed that both GRNLY and LUV-GRNLY induce a rather apoptotic type of cell death, although LUV-GRNLY was more cytotoxic than GRNLY alone. Indeed, the silencing of the pro-apoptotic protein Bak in the mutant Jurkat-shBak cel ne was able to fully inhibit cell death induced by both treatments compared with it ositive control (Jurkat plvTHM), indicating that GRNLY and LUV-GRNLY-induced cel eath depends on the presence of the pro-apoptotic proteins Bak and Bax and proceed hrough the mitochondrial apoptosis pathway (Figure 3B). 2.4. Analysis of the Mechanism of Cell Death Induced by GRNLY and LUV-GRNLY in Jurkat Cells 2.4. Analysis of the Mechanism of Cell Death Induced by GRNLY and LUV-GRNLY in Jurkat Cells (B,C) Jurkat and mutant cells (Jurkat-Bcl-xL, Jurkat-plvTHM and Jurkat-shBak) were treated with 7.5 µM of GRNLY or LUV-GRNLY, respectively, for 24 h. Cell death was determined by exposure of PS by staining with annexin-V-APC and analyzing by flow cytometry. The results are expressed as the mean ± SD of 3 independent experiments. *** p < 0.001. he dot-plots (upper, left panel) represent the evolution of treated cell population compared to th The dot-plots (upper, left panel) represent the evolution of treated cell population compared to the control. The values shown correspond to a percentage of cells in each quadrant. The upper right figure corresponds to a graphical representation of obtained data. Data shown are representative of four different experiments. (B,C) Jurkat and mutant cells (Jurkat-Bcl-xL, Jurkat-plvTHM and Jurkat-shBak) were treated with 7.5 µM of GRNLY or LUV-GRNLY, respectively, for 24 h. Cell death was determined by exposure of PS by staining with annexin-V-APC and analyzing by flow cytometry. The results are expressed as the mean ± SD of 3 independent experiments. *** p < 0.001. Previous work has shown that recombinant 9 kDa GRNLY was able to induce apoptosis mainly through the mitochondrial apoptotic pathway [7]. In order to assess if LUV-GRNLY followed the same type of mechanism, we carried-out cytotoxicity experiments with modi- fied Jurkat cell lines: Jurkat-Bcl-xL, which over-expressed the anti-apoptotic protein Bcl-xL, and Jurkat-shBak, which did not express the pro-apoptotic protein Bak. Jurkat cells are naturally deficient in the expression of the pro-apoptotic protein Bax and thus, Jurkat- shBak is a double Bax and Bak mutant and, in consequence, is resistant to the intrinsic apoptosis pathway [22]. Indeed, the silencing of the pro-apoptotic protein Bak in the mutant Jurkat-shBak cell line was able to fully inhibit cell death induced by both treatments compared with its positive control (Jurkat plvTHM), indicating that GRNLY and LUV-GRNLY-induced cell Int. J. Mol. Sci. 2022, 23, 8705 6 of 13 per righ ntative o death depends on the presence of the pro-apoptotic proteins Bak and Bax and proceeds through the mitochondrial apoptosis pathway (Figure 3B). However, over-expression of the anti-apoptotic protein Bcl-xL in mutant cells provides protection against granulysin, but not against LUV-GRNLY (Figure 3C), suggesting that the LUV-GRNLY-induced cell death signal is more powerful than that of GRNLY alone. 2.5. GRNLY and LUV-GRNLY Treatments Increase PUMA, Bim and Bcl-xL Expression the induction of expression of BH3-only pro-apoptotic proteins of the Bcl-2 supe such as Bim and PUMA [27] Since the mitochondrial apoptotic pathway is impl 2.5. GRNLY and LUV-GRNLY Treatments Increase PUMA, Bim and Bcl-xL Expression the induction of expression of BH3-only pro-apoptotic proteins of the Bcl-2 supe such as Bim and PUMA [27] Since the mitochondrial apoptotic pathway is impli The mitochondrial apoptotic pathway or intrinsic cell death pathway is initiated by the induction of expression of BH3-only pro-apoptotic proteins of the Bcl-2 superfamily, such as Bim and PUMA [27]. Since the mitochondrial apoptotic pathway is implicated in GRNLY- or LUV-GRNLY-induced cell death, we next studied if GRNLY or LUV-GRNLY was able to induce Bim or PUMA expression in Jurkat cells. such as Bim and PUMA [27]. Since the mitochondrial apoptotic pathway is implicated in GRNLY- or LUV-GRNLY-induced cell death, we next studied if GRNLY or LUV-GRNLY was able to induce Bim or PUMA expression in Jurkat cells. As shown in Figure 4, we observed that GRNLY clearly induced PUMA expression, while the induction of Bim was rather limited. However, LUV-GRNLY clearly induced the expression of both Bim and PUMA further demonstrating that it is a more potent p As shown in Figure 4, we observed that GRNLY clearly induced PUMA expression, while the induction of Bim was rather limited. However, LUV-GRNLY clearly induced the expression of both Bim and PUMA, further demonstrating that it is a more potent cellular stressor and cell death inductor than GRNLY alone. We also confirmed the absence of expression of Bax in these cells, which is not induced by either GRNLY or LUV-GRNLY. Re- markably, both GRNLY and LUV-GRNLY also induced the expression of the anti-apoptotic member of the Bcl-2 family Bcl-xL, probably as a mechanism of cell defense. Finally, the low levels of Bcl-2 were not affected by the treatments. the expression of both Bim and PUMA, further demonstrating that it is a more potent cellular stressor and cell death inductor than GRNLY alone. We also confirmed the ab- sence of expression of Bax in these cells, which is not induced by either GRNLY or LUV- GRNLY. Remarkably, both GRNLY and LUV-GRNLY also induced the expression of the anti-apoptotic member of the Bcl-2 family Bcl-xL, probably as a mechanism of cell defense. Finally, the low levels of Bcl-2 were not affected by the treatments. Figure 4. Expression levels of proteins from the Bcl-2 family upon treatment with GRNLY or LUV- GRNLY. 2.4. Analysis of the Mechanism of Cell Death Induced by GRNLY and LUV-GRNLY in Jurkat Cells 2.4. Analysis of the Mechanism of Cell Death Induced by GRNLY and LUV-GRNLY in Jurkat Cells s a ) e e ea e i 5 μ o G N Y o U G N Y, espe i e y, o Ce ea as determined by exposure of PS by staining with annexin-V-APC and analyzing by flow cytometry The results are expressed as the mean ± SD of 3 independent experiments. *** p < 0.001. 2.5. GRNLY and LUV-GRNLY Treatments Increase PUMA, Bim and Bcl-xL Expression The mitochondrial apoptotic pathway or intrinsic cell death pathway is initiated by 2.5. GRNLY and LUV-GRNLY Treatments Increase PUMA, Bim and Bcl-xL Expression the induction of expression of BH3-only pro-apoptotic proteins of the Bcl-2 supe such as Bim and PUMA [27] Since the mitochondrial apoptotic pathway is impl The expression of Bim, PUMA, Bax, Bcl-xL or Bcl-2 in Jurkat cells treated with 7.5 μM of GRNLY or LUV-GRNLY for 24 h was analyzed by Western blot using specific antibodies. Cell ly- sates (5 × 106 cells) were separated by SDS-PAGE 12% polyacrylamide gel, transferred to PVDF membranes and analyzed by Western blot using specific antibodies. Levels of β-actin were used as a control of protein loading. 2.6. Toxicity against PBMC and T Cell Blasts from Healthy Donors Figure 4. Expression levels of proteins from the Bcl-2 family upon treatment with GRNLY or LUV- GRNLY. The expression of Bim, PUMA, Bax, Bcl-xL or Bcl-2 in Jurkat cells treated with 7.5 µM of GRNLY or LUV-GRNLY for 24 h was analyzed by Western blot using specific antibodies. Cell lysates (5 × 106 cells) were separated by SDS-PAGE 12% polyacrylamide gel, transferred to PVDF membranes and analyzed by Western blot using specific antibodies. Levels of β-actin were used as a control of protein loading. 2.6. Toxicity against PBMC and T Cell Blasts from Healthy Donors Figure 4. Expression levels of proteins from the Bcl-2 family upon treatment with GRNLY or LUV- GRNLY. The expression of Bim, PUMA, Bax, Bcl-xL or Bcl-2 in Jurkat cells treated with 7.5 μM of GRNLY or LUV-GRNLY for 24 h was analyzed by Western blot using specific antibodies. Cell ly- sates (5 × 106 cells) were separated by SDS-PAGE 12% polyacrylamide gel, transferred to PVDF membranes and analyzed by Western blot using specific antibodies. Levels of β-actin were used as a control of protein loading. Figure 4. Expression levels of proteins from the Bcl-2 family upon treatment with GRNLY or LUV- GRNLY. The expression of Bim, PUMA, Bax, Bcl-xL or Bcl-2 in Jurkat cells treated with 7.5 µM of GRNLY or LUV-GRNLY for 24 h was analyzed by Western blot using specific antibodies. Cell lysates (5 × 106 cells) were separated by SDS-PAGE 12% polyacrylamide gel, transferred to PVDF membranes and analyzed by Western blot using specific antibodies. Levels of β-actin were used as a control of protein loading. Figure 4 Expression levels of proteins from the Bcl 2 family upon treatment with GRNLY or LUV Figure 4. Expression levels of proteins from the Bcl-2 family upon treatment with GRNLY or LUV Figure 4. Expression levels of proteins from the Bcl-2 family upon treatment with GRNLY or LUV- GRNLY. 2.5. GRNLY and LUV-GRNLY Treatments Increase PUMA, Bim and Bcl-xL Expression the induction of expression of BH3-only pro-apoptotic proteins of the Bcl-2 supe such as Bim and PUMA [27] Since the mitochondrial apoptotic pathway is impl The expression of Bim, PUMA, Bax, Bcl-xL or Bcl-2 in Jurkat cells treated with 7.5 μM of GRNLY or LUV-GRNLY for 24 h was analyzed by Western blot using specific antibodies. Cell ly- sates (5 × 106 cells) were separated by SDS-PAGE 12% polyacrylamide gel, transferred to PVDF membranes and analyzed by Western blot using specific antibodies. Levels of β-actin were used as a control of protein loading. Figure 4. Expression levels of proteins from the Bcl-2 family upon treatment with GRNLY or LUV- GRNLY. The expression of Bim, PUMA, Bax, Bcl-xL or Bcl-2 in Jurkat cells treated with 7.5 µM of GRNLY or LUV-GRNLY for 24 h was analyzed by Western blot using specific antibodies. Cell lysates (5 × 106 cells) were separated by SDS-PAGE 12% polyacrylamide gel, transferred to PVDF membranes and analyzed by Western blot using specific antibodies. Levels of β-actin were used as a control of protein loading. 3. Discussion 3. Discussion Our previous studies using recombinant TRAIL anchored to the surface of liposomes (LUV-TRAIL) demonstrated that this new formulation was much more potent than solu- ble TRAIL both in different tumor types both in vitro and in vivo [22–24]. Although the liposomes for disease treatment have been extensively used in different diseases, lipo- somes have also been used as a vehicle to encapsulate drugs [28–30], or more recently, mRNA in vaccine development [31]. However, attachment of bioactive compounds on the liposome surface has been a less explored therapeutic strategy. In this line, the attachment of TRAIL to the surface of liposomes, an improvement proposed by our group, resulted in increased anti-tumor bioactivity, and in fact tried to mimic the natural way of secretion of TRAIL and FasL bound to exosomes, described initially in human T cell blasts [32–34]. Liposome-based treatments show several advantages: biocompatibility, increased efficacy and stability of encapsulated agents as well as reduction of their toxicity, and provide selective passive targeting to tumor tissues. In fact, liposome-based formulations would take advantage of the well-known enhancing permeability and retention (EPR) effect. Ac- cording to the EPR effect, nanoparticles in the 100 nm diameter range spontaneously lo- calize in tumor sites by extravasation in the leaky blood capillary system irrigating the Our previous studies using recombinant TRAIL anchored to the surface of liposomes (LUV-TRAIL) demonstrated that this new formulation was much more potent than soluble TRAIL both in different tumor types both in vitro and in vivo [22–24]. Although the lipo- somes for disease treatment have been extensively used in different diseases, liposomes have also been used as a vehicle to encapsulate drugs [28–30], or more recently, mRNA in vaccine development [31]. However, attachment of bioactive compounds on the liposome surface has been a less explored therapeutic strategy. In this line, the attachment of TRAIL to the surface of liposomes, an improvement proposed by our group, resulted in increased anti-tumor bioactivity, and in fact tried to mimic the natural way of secretion of TRAIL and FasL bound to exosomes, described initially in human T cell blasts [32–34]. Liposome-based treatments show several advantages: biocompatibility, increased efficacy and stability of encapsulated agents as well as reduction of their toxicity, and provide selective passive targeting to tumor tissues. In fact, liposome-based formulations would take advantage of the well-known enhancing permeability and retention (EPR) effect. 2.6. Toxicity against PBMC and T Cell Blasts from Healthy Donors 2.6. Toxicity against PBMC and T Cell Blasts from Healthy Donors * p < 0.5; ** p < 0.01; *** p < 0.001. Figure 5. Toxicity of GRNLY or LUV-GRNLY towards fresh PBMC or 7-day T cell blasts obtained from healthy donors. (A) Freshly isolated PBMCs from healthy donors were treated for 24 h with increasing concentrations of LUV-GRNLY, as indicated. (B) Seven-day T cell blasts from the same healthy donors were treated for 24 h with increasing concentrations of GRNLY or LUV-GRNLY, as indicated. Then, cells were stained with annexin-V-FITC and analyzed using flow cytometry. * p < 0.5; ** p < 0.01; *** p < 0.001. 2.6. Toxicity against PBMC and T Cell Blasts from Healthy Donors 2.6. Toxicity against PBMC and T Cell Blasts from Healthy Donors 2.6. Toxicity against PBMC and T Cell Blasts from Healthy Donors We have previously shown that recombinant GRNLY, while being toxic against tu- mor cells, was not active against fresh PBMC obtained from healthy donors [7]. We per- formed a similar experiment using LUV-GRNLY and found that it was toxic against freshly isolated PBMC (Figure 5A). In addition, we also demonstrated that, while GRNLY We have previously shown that recombinant GRNLY, while being toxic against tumor cells, was not active against fresh PBMC obtained from healthy donors [7]. We performed a similar experiment using LUV-GRNLY and found that it was toxic against freshly isolated PBMC (Figure 5A). In addition, we also demonstrated that, while GRNLY was not toxic against day-7 T cell blasts, at least until a concentration of 7.5 µM, LUV-GRNLY proved to be highly toxic (Figure 5B). 7 of 13 LUV- Int. J. Mol. Sci. 2022, 23, 8705 Figure 5. Toxicity of GRNLY or LUV-GRNLY towards fresh PBMC or 7-day T cell blasts obtained from healthy donors. (A) Freshly isolated PBMCs from healthy donors were treated for 24 h with increasing concentrations of LUV-GRNLY, as indicated. (B) Seven-day T cell blasts from the same healthy donors were treated for 24 h with increasing concentrations of GRNLY or LUV-GRNLY, as indicated. Then, cells were stained with annexin-V-FITC and analyzed using flow cytometry. * p < 0.5; ** p < 0.01; *** p < 0.001. Figure 5. Toxicity of GRNLY or LUV-GRNLY towards fresh PBMC or 7-day T cell blasts obtained from healthy donors. (A) Freshly isolated PBMCs from healthy donors were treated for 24 h with increasing concentrations of LUV-GRNLY, as indicated. (B) Seven-day T cell blasts from the same healthy donors were treated for 24 h with increasing concentrations of GRNLY or LUV-GRNLY, as indicated. Then, cells were stained with annexin-V-FITC and analyzed using flow cytometry. * p < 0.5; ** p < 0.01; *** p < 0.001. Figure 5. Toxicity of GRNLY or LUV-GRNLY towards fresh PBMC or 7-day T cell blasts obtained from healthy donors. (A) Freshly isolated PBMCs from healthy donors were treated for 24 h with increasing concentrations of LUV-GRNLY, as indicated. (B) Seven-day T cell blasts from the same healthy donors were treated for 24 h with increasing concentrations of GRNLY or LUV-GRNLY, as indicated. Then, cells were stained with annexin-V-FITC and analyzed using flow cytometry. 3. Discussion 3. Discussion A possible explanation for the increased cyto- toxicity of LUV-GRNLY, as mentioned above, is that association of GRNLY to liposome surface increases the local concentration of recombinant protein that can interact with cell membrane surface, in turn increasing its bioactivity. We have also investigated the cell death mechanisms induced by LUV-GRNLY, finding that it was similar to that previously described for recombinant GRNLY, mainly depending on the mitochondrial apoptotic pathway. Remarkably, we found that although LUV- GRNLY-induced cell death was abrogated in the absence of Bax and Bak expression in Jurkat-shBak cells, LUV-GRNLY was still effective against Jurkat cells over-expressing Bcl-xL, while GRNLY was not. This is an interesting observation regarding the possible clinical application of our formulation, since in many instances, tumor cells resistant to conventional chemotherapy over-express anti-apoptotic members of the Bcl-2 family [37]. This, in fact, has led to the recent introduction, into the antitumor arsenal, of BH3 mimetics that counteract these types of resistance, such as venetoclax, which has been approved for the treatment of a variety of hematological malignancies [38,39]. In a previous study, we showed that although recombinant GRNLY was toxic against hematological tumor cells, it was not active against fresh PBMCs obtained from healthy donors [7]. This indicated that GRNLY had some tumor selectivity, probably dependent on the different membrane lipid compositions of normal and tumor cells [20,40], something that has been confirmed by its absence of in vivo toxicity [15]. However, LUV-GRNLY proved to be toxic against freshly isolated PBMCs and also against T cell blasts, indicating that increases in its bioactivity could also lead to undesired secondary effects. Although one of the advantages of liposomal formulations is the reduction in toxic effects of the bioactive molecules, mainly for encapsulated drugs, a crucial step in the generation of functionalized liposomes is the final concentration of the bioactive compounds either encapsulated or attached to their surface, to avoid their adverse effects. One possibility that could explain the toxicity of LUV-GRNLY against healthy cells would be that the liposome surface is saturated with GRNLY molecules. In this line, previous studies by our group have demonstrated that reducing the concentration of bioactive compounds in liposomal formulations reduced their toxic adverse effects while retaining their cytotoxic effects against tumor cells [25]. 3. Discussion 3. Discussion According to the EPR effect, nanoparticles in the 100 nm diameter range spontaneously localize in tumor sites by extravasation in the leaky blood capillary system irrigating the tumor [35,36]. calize in tumor sites by extravasation in the leaky blood capillary system irrigating the tumor [35,36]. Based on our previous work, our working hypothesis was that the association of GRNLY with liposomes could increase protein concentration at the site of contact with the ta get cell a d the efo e it could pote tiate the cytoto icity of the ad i iste ed dose Based on our previous work, our working hypothesis was that the association of GRNLY with liposomes could increase protein concentration at the site of contact with the target cell, and, therefore, it could potentiate the cytotoxicity of the administered dose. This approach could lead to a reduction in the dose needed to attain anti-tumor effects. target cell, and, therefore, it could potentiate the cytotoxicity of the administered dose. This approach could lead to a reduction in the dose needed to attain anti-tumor effects. Analysis of interaction of recombinant GRNLY containing a histidine tag with LUV demonstrated that the attachment of GRNLY using a novel Ni2+-NTA–containing lipid in Analysis of interaction of recombinant GRNLY containing a histidine tag with LUV demonstrated that the attachment of GRNLY using a novel Ni2+-NTA–containing lipid in the liposome composition was extremely efficient, with recoveries close to 100% at 10–15 µM GRNLY concentrations. The chemical basis for conjugation of GRNLY to lipo- some surface is the formation of a stable coordination complex between the histidine tag of the recombinant GRNLY and the Ni2+ cation of DOG-NTA-Ni. When higher concentrations Int. J. Mol. Sci. 2022, 23, 8705 8 of 13 8 of 13 of recombinant GRNLY (more than 15 µM) were used, the liposome surface was saturated, not admitting higher loading of more GRNLY molecules. In any case, assuming that the binding efficiency of GRNLY to liposomes surface is 100%, we estimated that each liposome should harbor around 1438 GRNLY molecules on its surface when using 15 µM GRNLY. We have shown that our hypothesis was correct, since the cytotoxicity of LUV-GRNLY is higher than that of the same dose of GRNLY in the soluble phase, reducing the LC50 against Jurkat cells between 2- and 3-fold. 3. Discussion 3. Discussion Therefore, further studies generating LUV-GRNLY with lower amounts of GRNLY on their surface could show that this non-saturated LUV-GRNLY is able to retain its anti-tumoral effects while reducing its toxic effects against healthy cells. 4.2. Expression and Purification of 9 kDa Granulysin Synthetic genes encoding 6× His-tagged 9 kDa granulysin, kindly provided by Dr. Alan M. Krensky, were synthesized by Geneart GmbH (Thermo Fisher Scientific Re- gensburg, Regensburg, Germany) and subcloned between Cla I and XbaI sites into pCR3.1, resulting in pCR3.1-GRNLY, as indicated in [17]. Then, 293 T cells were transiently trans- fected with the vector using calcium phosphate, and supernatants were analyzed for protein expression. The Cla I/XbaI -digested fragments of pCR3.1-GRNLY were then ligated into the Cla I/XbaI digested backbone of plasmid pPICZα A to obtain pPICZα A-GRNLY. The plasmid was then amplified in E.coli and isolated by NucleoSpin® Plasmid EasyPure (Macherey-Nagel, Düren, Germany). Plasmids were linearized with SacI (Takara) and purified by Ilustra™GFX™PCR DNA and Gel Band Purification kit (GE Healthcare). p y ( ) Competent cultures of Pichia pastoris were then transfected with the pPICZαA vector containing recombinant 9 kDa granulysin and expanded in aseptic YPD agar (Formedium, Hunstanton, UK) plate supplemented with zeocin (100 µg/mL) (Invitrogen, Carlsbad, CA, USA) for 3 days, as indicated in [17]. One of the colonies was transferred in a BMGY medium (10 g/L yeast extract; 20 g/L de peptone; 100 mM potassium phosphate pH = 6.0; 13.4 g/L yeast base; 1 ml/L glycerol and 0.4 mg/L biotin, all purchased from Formedium, Hunstanton, UK) and was incubated at 30 ◦C and 250 rpm for 24 h. Next, culture medium was exchanged with BMMY medium (10 g/L yeast extract; 20 g/L peptone; 100 mM phosphate buffer pH = 6.0; 13.4 g/L yeast base; 0.5 mL/L methanol y 0.4 mg/L de biotin, all purchased from Formedium, Hunstanton, UK) by centrifugation at 4400 rpm for 25 min. Then, yeast culture was incubated at 18 ◦C with agitation for 48 h. Every 24 h, methanol was added in a weight ratio of 1:100 in order to induce granulysin expression. For protein purification, the supernatant was filtered through 0.45 and 0.22 µm filters (Merck Milli- pore, Tullagreen, Ireland) and concentrated with a Pellicon XL Ultracel 50 cm2 cassette (Merck Millipore, Jaffrey, NH, USA) connected to a vacuum pump. The concentrated supernatant was dialyzed overnight in a dialysis buffer (300 mM NaCl; 50 mM Tris-HCl y 20 mM imidazole, pH = 7.8) at 4 ◦C. Next, the dialyzed fraction was incubated with Ni-NTA resin (Qiagen, Redwood City, CA, USA) at 4 ◦C for 2 h, gently shaking. 4. Materials and Methods 4.1. Cell Culture The acute T cell leukemia Jurkat cell line was purchased from ATCC. Cells over- expressing the anti-apoptotic protein Bcl-xL (Jurkat-Bcl-xL) and cells lacking the expression of the pro-apoptotic protein Bak (Jurkat-shBak) were generated in our laboratory using a lentiviral system, as previously described [22]. These cell lines are completely resistant to doxorubicin, a drug that kills cells through the mitochondrial apoptotic pathway [22]. Cell lines were routinely cultured in RPMI 1640 medium with GlutaMAX (Life Technologies, Paisley, UK) supplemented with 10% fetal calf serum (FCS), penicillin (1000 U/mL) and streptomycin (10 mg/mL) (PanBiotech, Aidenbach, Germany) at 37 ◦C and 5% CO2 using standard procedures. Human PBMCs from healthy donors were obtained by Ficoll density centrifugation from Leukopacks provided by the “Banco de Sangre y Tejidos de Aragón”. T-cell blasts were generated from PBMCs from the same donors by stimulation with PHA at 10 µg/mL overnight, with posterior washing and culture for at least 7 days in the Int. J. Mol. Sci. 2022, 23, 8705 9 of 13 9 of 13 presence of 30 IU/mL of IL-2, with medium changes each 48 h, as described in [41]. The use of human samples was approved by the “Comité Etico de la Investigación de Aragón” (CEICA) and written informed consent was obtained from each donor. 4.4. Optimization Procedure for LUV-GRNLY Synthesis; Binding and Affinity Assays In order to examine the affinity of the histidine-tagged granulysin to DOGS-NTA-Ni and the protein load that each liposome can harbor on its surface, different concentrations of granulysin (4, 6, 8, 10, 15 y 30 µM) were incubated with liposomes in KHE buffer for 30 min at 37 ◦C and 800 rpm. Every mixture was ultracentrifugated for 5 h at 14,000 rpm in an L8-60M Ultracentrifuge (Beckman and Coulter). The supernatant was separated from the pellet and dissolved in the same volume of KHE buffer. Finally, the presence of protein in both fractions was analyzed by Western-blot technique using an anti-His antibody (GenScript, Piscataway, NJ, USA) and Coomassie blue staining in 15% SDS-PAGE gel electrophoresis. Equally, in order to demonstrate that granulysin binds to liposome through DOGS-NTA-NI, liposomes without DOGS-NTA-Ni (LUV.0) were synthetized and incubated with increased concentrations of granulysin. The protein union to the surface was assessed by reproducing the same procedure. 4.2. Expression and Purification of 9 kDa Granulysin The resin was washed 3 times and then transferred in a gravity-flow column in which the protein was eluted with an elution buffer composed of 400 mM imidazole, 300 mM NaCl and 50 mM de Tris- HCl, pH 7.4. The imidazole was exchanged with KHE buffer using Amicon® filters (Merck Millipore, Tullagreen, Ireland). Protein concentration was measured using a BCA assay (Thermo Fisher, Rockford, IL, USA), and its purity was checked by SDS-PAGE in 15% polyacrylamide gel, Coomassie blue staining and immunoblot incubated with specific anti-His antibody (Genescript, Piscataway, NJ, USA). Finally, the protein was sterilized through a 0.22 µm filter and was stored at 4 ◦C. The stability of the protein was maintained at 4 ◦C for at least 1 month. 4.3. Large Unilamellar Vesicle (LUV) Synthesis and Preparation of Lipid Nanoparticles Coated with 9 kDa Recombinant Granulysin (LUV-GRNLY) The generation of large unilamellar vesicles (LUVs) was achieved by preparing a mix- ture of phosphatidylcholine, sphingomyelin, cholesterol, 1,2-dioleoyl-sn-glycero-3[N-(5- amino-1-carboxypentyl)-iminodiacetic acid]succinyl (DOGS-NTA-Ni) and polyethylene glycol (PEG) in a weight ratio of 55:30:10:5:5, previously dissolved in chloroform/methanol (2:1), as originally described in [42]. All lipids were purchased from Avanti Polar Lipids, Alabama, AL, USA. The chloroform and methanol were removed under nitrogen gas for 10 min and then under vacuum conditions at 45 ◦C for 6 h. After that, lipids were dissolved in a KHE buffer, and the aliquots were frozen overnight (−20 ◦C). The next day, aliquots were thawed and extruded at least 10 times through a polycarbonate filter with 200 nm Int. J. Mol. Sci. 2022, 23, 8705 10 of 13 pore diameter (Whatman, Maidstone, UK) using an extruder (Northern Lipids, Burnaby, BC, Canada), to generate classical large unilamellar vesicles (LUVs), which mimic the com- position of natural exosomes. Finally, LUVs were incubated with 9 KDa granulysin in KHE buffer for 30 min at 37 ◦C with gentle shaking (800 rpm). During this step, the polyhistidine tail of granulysin established a complex of coordination with Ni2+ provided by a chelating lipid (DOGS-NTA-Ni) in the liposome composition that remained attached permanently. LUV-GRNLY could be stored at 4 ◦C for 1 month without losing its bioactivity. 4.5. Estimation of the Number of GRNLY Molecules per Liposome Assuming that 100% of the generated liposomes are unilamellar and that their di- ameters are approximately 150 nm, the lipid number that composes one liposome can be calculated with the following equation: N◦lipo TOT =  4π  d 2 2 + 4π h d 2 −h i2 a a where: d is the diameter of the liposome (150 nm) d is the diameter of the liposome (150 nm) h is the thickness of the liposome (5 nm) a is the area of the hydrophilic heads of phospholipids (0.55 nm2) From the equation, we calculated that one liposome is composed of approximately 240,000 lipid molecules, of which 5% correspond to DOGS-NTA-Ni. Therefore, the number of DOGS-NTA-Ni molecules that would be theoretically available for binding to the protein was 12,000. For a final concentration of lipids/mL of 2.5 mM, we calculated that the total number of liposomes/mL would be 6.26 × 1012. Finally, if we prepared an aliquot of 15 µM of LUV-GRNLY, the number of GRNLY molecules in 1 mL would be 9 × 1015. Assuming that the bonding efficiency of GRNLY to liposome surfaces is 100%, we estimated that each liposome should harbor around 1438 GRNLY molecules on its surface. 4.7. Western-Blot Analysis 4.7. Western-Blot Analysis A total of 5 × 106 cells were lysed with 100 µL of a lysis buffer 1× (1% Triton-X-100; 150 mM NaCl; 50 mM Tris/HCl pH 7.6; 10% v/v glycerol; 1mM EDTA; 1mM sodium orthovanadate; 10 mM sodium pyrophosphate; 10 µg/mL leupeptin; 10 mM sodium fluoride; 1 mM methyl phenyl sulfide, Sigma, St. Louis, MO, USA) for 30 min in ice. The mixture was centrifuged at 12,000 rpm for 20 min at 4 ◦C. The protein concentration in supernatant was analyzed using a BCA assay (Thermo Fisher, Rockford, IL, USA) and was mixed with lysis buffer 3× (SDS; 150 mM Tris/HCl; 0.3 mM sodium molybdate; 30% v/v glycerol; 30 mM sodium pyrophosphate; 30 mM sodium fluoride; 0.006% w/v bromophenol blue; 30% v/v 2-mercaptoethanol, all purchased from Sigma, St. Louis, MO, USA). Protein separation was performed using SDS-PAGE 12% polyacrylamide gel, and then proteins were transferred to nitrocellulose membranes using a semi dry electro transfer (Biorad, Alcobendas, Spain). Membranes were blocked with TBS-T buffer (Tris/HCl 10 mM, pH 8; NaCl 0.12 M; Tween-20 0.1%, thimerosal 0.1 g/L, Sigma, St. Louis, MO, USA) containing 5% skimmed milk. Protein detection was performed by the Western-blot technique, using specific antibodies against PUMA (Novus International, St. Louis, MO, USA), Bax, Bim, Bcl- xL (Cell Signaling, Danvers, MA, USA), Bcl-2 (Santa Cruz, Dallas, USA) and β-actin (Cell Signaling, Danvers, MA, USA) that were incubated overnight at 4 ◦C with agitation. Anti- rabbit and anti-mouse secondary antibodies labeled with peroxidase (Sigma, St. Louis, MO, USA) were incubated for 1 h at room temperature, gently shaking. Proteins were revealed with the reagent Pierce ELC Western Blotting Substrate (Thermo Scientific, Rockford, IL, USA) using Amersham Imager 680 (GE Healthcare Life Sciences). 4.6. In Vitro Cytotoxicity Assays—Apoptosis Quantification by Flow Cytometry Cytotoxicity assays were carried-out as follows: 50 µL aliquots of 3 × 104 cells were seeded per well in 96-well plates and 50 µL aliquots of increasing concentrations of GRNLY or LUV-GRNLY were added and incubated for 24 h at 37 ◦C. For controls wells the same volume of KHE buffer was added. Cell death was analyzed using a FACScalibur flow cytometer (BD, Biosciences, Franklin Lakes, NJ, USA) after incubation with annexin-V- FITC or APC (BD Biosciences) in annexin binding buffer (140 mM NaCl, 2.5 mM CaCl2, 10 mM HEPES/NaOH, pH 7.4) for 20 min. The 7-AAD staining (BD Biosciences) was also performed in some experiments. The data obtained was analyzed using FlowJo 0.7 (Tree star Inc., San Francisco, CA, USA). Int. J. Mol. Sci. 2022, 23, 8705 11 of 13 11 of 13 1. Clayberger, C.; Finn, M.W.; Wang, T.; Saini, R.; Wilson, C.; Barr, V.A.; Sabatino, M.; Castiello, L.; Stroncek, D.; Krensky, A.M. 15 kDa Granulysin Causes Differentiation of Monocytes to Dendritic Cells but Lacks Cytotoxic Activity. J. Immunol. 2012, 188, 6119–6126. [CrossRef] [PubMed] 4.8. Statistical Analysis Computer-based statistical analysis was performed using the GraphPad Prism pro- gram (GraphPad Software Inc., San Diego, CA, USA). For quantitative variables, results are shown as median ± standard deviation (SD). Statistical significance was evaluated using Student t test, and differences were considered significant when p < 0.05. Author Contributions: Conceptualization, A.A. and L.M.-L.; methodology, J.M.-B. and I.M.; investi- gation, R.S.-A., P.G.-O., J.M.-B. and R.I.-P.; resources, J.M.-B. and I.M.; data curation, R.S.-A. and A.A.; writing—original draft preparation, R.S.-A. and A.A.; writing—review and editing, L.M.-L., J.M.-B. and IM; visualization, R.S.-A.; supervision, A.A. and L.M.-L.; project administration, A.A.; funding acquisition, A.A. All authors have read and agreed to the published version of the manuscript. Funding: This research was financed in part by the project PID2019-105128RB-I00 financed by MCIN/AEI/10.13039/501100011033/ and “FEDER Una manera de hacer Europa” to AA and IM and was also supported by Government of Aragon grant B31_20R to AA. PGO was supported by a Senescyt fellowship (Ecuador). Funding: This research was financed in part by the project PID2019-105128RB-I00 financed by MCIN/AEI/10.13039/501100011033/ and “FEDER Una manera de hacer Europa” to AA and IM and was also supported by Government of Aragon grant B31_20R to AA. PGO was supported by a Senescyt fellowship (Ecuador). Institutional Review Board Statement: The study was conducted in accordance with the Declaration of Helsinki, and approved by the Ethics Committee for Research of the Government of Aragón, “Comité Etico de la Investigación de Aragón” (CEICA; protocol code PI19/452, date of approval 12 April 2019). Informed Consent Statement: Informed consent was obtained from all donors. Data Availability Statement: The data presented in this study are available on request from the corresponding author. Data Availability Statement: The data presented in this study are available on request from the corresponding author. Conflicts of Interest: The authors declare no conflict of interest. Conflicts of Interest: The authors declare no conflict of interest. Conflicts of Interest: The authors declare no conflict of interest. [ ] [ ] 2. Clayberger, C.; Krensky, A.M. Granulysin. Curr. Opin. Immunol. 2003, 15, 560–565. [CrossRef] 1. Clayberger, C.; Finn, M.W.; Wang, T.; Saini, R.; Wilson, C.; Barr, V.A.; Sabatino, M.; Castiello, L.; Stroncek, D.; Krensky, A.M. 15 kDa Granulysin Causes Differentiation of Monocytes to Dendritic Cells but Lacks Cytotoxic Activity. J. Immunol. 2012, 188, 6119–6126. [CrossRef] [PubMed] 2. Clayberger, C.; Krensky, A.M. Granulysin. Curr. Opin. Immunol. 2003, 15, 560–565. [CrossRef] References An antimicrobial activity of cytolytic T cells mediated by granulysin. Science 1998, 282, 121–125. [CrossRef] 7. Aporta, A.; Catalán, E.; Galán-Malo, P.; Ramírez-Labrada, A.; Pérez, M.; Azaceta, G.; Palomera, L.; Naval, J.; Marzo, I.; Pardo, J.; et al. Granulysin induces apoptotic cell death and cleavage of the autophagy regulator Atg5 in human hematological tumors. Biochem. Pharmacol. 2014, 87, 410–423. [CrossRef] 8. Gamen, S.; Hanson, D.A.; Kaspar, A.; Naval, J.; Krensky, A.M.; Anel, A. Granulysin-induced apoptosis. I. Involvement of at least two distinct pathways. J. Immunol. 1998, 161, 1758–1764. p y 9. Martinez-Lostao, L.; de Miguel, D.; Al-Wasaby, S.; Gallego-Lleyda, A.; Anel, A. Death ligands and granulysin: Mechanisms of tumor cell death induction and therapeutic opportunities. Immunotherapy 2015, 7, 883–892. [CrossRef] 10. Kishi, A.; Takamori, Y.; Ogawa, K.; Takano, S.; Tomita, S.; Tanigawa, M.; Niman, M.; Kishida, T.; Fujita, S. Differential expression of granulysin and perforin by NK cells in cancer patients and correlation of impaired granulysin expression with progression of cancer. Cancer Immunol. Immunother. 2002, 50, 604–614. [CrossRef] 11. Pagès, F.; Berger, A.; Camus, M.; Sanchez-Cabo, F.; Costes, A.; Molidor, R.; Mlecnik, B.; Kirilovsky, A.; Nilsson, M.; Damotte, D.; et al. Effector Memory T Cells, Early Metastasis, and Survival in Colorectal Cancer. N. Eng. J. Med. 2005, 353, 2654–2666. [CrossRef] [PubMed] 12. Sparrow, E.; Bodman-Smith, M. Granulysin: The attractive side of a natural born killer. Immunol. Lett. 2020, 217, 126–132. [CrossRef] [PubMed] 13. Tong, X.; Qu, X.; Wang, M. A Four-Gene-Based Prognostic Model Predicts Overall Survival in Patients with Cutaneous Melanoma. Front. Oncol. 2021, 11, 639874. [CrossRef] [PubMed] 14. Huang, L.P.; Lyu, S.C.; Clayberger, C.; Krensky, A.M. Granulysin-Mediated Tumor Rejection in Transgenic Mice. J. Immunol. 2007, 178, 77–84. [CrossRef] 15. Al-Wasaby, S.; de Miguel, D.; Aporta, A.; Naval, J.; Conde, B.; Martínez-Lostao, L.; Anel, A. In vivo potential of recombinant granulysin against human tumors. Oncoimmunology 2015, 4, e1036213. [CrossRef] 16. Al-Wasaby, S.; Guerrero-Ochoa, P.; Ibáñez-Pérez, R.; Soler, R.; Conde, B.; Martínez-Lostao, L.; Anel, A. In vivo potential of recombinant granulysin against human melanoma. Cancer Treat. Res. Commun. 2021, 27, 100355. [CrossRef] ; Guerrero-Ochoa, P.; Al-Wasaby, S.; Navarro, R.; Tapia-Galisteo, A.; De Miguel, D.; Gonzalo, O.; Conde 17. Ibáñez Pérez, R.; Guerrero Ochoa, P.; Al Wasaby, S.; Navarro, R.; Tapia Galisteo, A.; De Miguel, D.; Gonzalo, O.; Conde, B.; Martínez-Lostao, L.; Hurtado-Guerrero, R.; et al. Anti-tumoral potential of a human granulysinbased, CEA-targeted cytolytic immunotoxin. OncoImmunology 2019, 8, 1641392. [CrossRef] 18. References 1. Clayberger, C.; Finn, M.W.; Wang, T.; Saini, R.; Wilson, C.; Barr, V.A.; Sabatino, M.; Castiello, L.; Stroncek, D.; Krensky, A.M. 15 kDa Granulysin Causes Differentiation of Monocytes to Dendritic Cells but Lacks Cytotoxic Activity. J. Immunol. 2012, 188, 6119–6126. [CrossRef] [PubMed] 2 Clayberger C ; Krensky A M Granulysin Curr Opin Immunol 2003 15 560 565 [CrossRef] 12 of 13 Int. J. Mol. Sci. 2022, 23, 8705 12 of 13 3. Peña, S.V.; Hanson, D.A.; Carr, B.A.; Goralski, T.J.; Krensky, A.M. Processing, subcellular localization, and function of 519 (granulysin), a human late T cell activation molecule with homology to small, lytic, granule proteins. J. Immunol. 1997, 158, 2680–2688. [PubMed] [ ] 4. Crespo, Â.; Mulik, S.; Dotiwala, F.; Ansara, J.; Sen Santara, S.; Ingersoll, K.; Ovies, C.; Junqueira, C.; T et al. Decidual NK Cells Transfer Granulysin to Selectively Kill Bacteria in Trophoblasts. Cell 2020, 182 [ ] Â.; Mulik, S.; Dotiwala, F.; Ansara, J.; Sen Santara, S.; Ingersoll, K.; Ovies, C.; Junqueira, C.; Tilburgs, T.; Stro al. Decidual NK Cells Transfer Granulysin to Selectively Kill Bacteria in Trophoblasts. Cell 2020, 182, 1125– et al. Decidual NK Cells Transfer Granulysin to Selectively Kill Bacteria in Trophoblasts. Cell 2020, 182, 1125 1139. [CrossRef] 5. Dotiwala, F.; Mulik, S.; Polidoro, R.; Ansara, J.; Burleigh, B.; Walch, M.; Gazzinelli, R.; Lieberman, J. Killer lymphocytes use granulysin, perforin and granzymes to kill intracellular parasites. Nat. Med. 2016, 22, 210–216. [CrossRef] wala, F.; Mulik, S.; Polidoro, R.; Ansara, J.; Burleigh, B.; Walch, M.; Gazzinelli, R.; Lieberman, J. Killer lym 5. Dotiwala, F.; Mulik, S.; Polidoro, R.; Ansara, J.; Burleigh, B.; Walch, M.; Gazzinelli, R.; Lieberman, J granulysin, perforin and granzymes to kill intracellular parasites. Nat. Med. 2016, 22, 210–216. [CrossR g y p g y p 6. Stenger, S.; Hanson, D.A.; Teitelbaum, R.; Dewan, P.; Niazi, K.R.; Froelich, C.J.; Ganz, T.; Thoma-Uszynski, S.; Melián, A.; B d C t l A ti i bi l ti it f t l ti T ll di t d b l i S i 1998 282 121 125 [C R f] g y p g y p 6. Stenger, S.; Hanson, D.A.; Teitelbaum, R.; Dewan, P.; Niazi, K.R.; Froelich, C.J.; Ganz, T.; Thoma-Uszynski, S.; Melián, A.; Bogdan, C.; et al. An antimicrobial activity of cytolytic T cells mediated by granulysin. Science 1998, 282, 121–125. [CrossRef] Bogdan, C.; et al. References Guerrero-Ochoa, P.; Aguilar-Machado, D.; Ibáñez-Pérez, R.; Macías-León, J.; Hurtado-Guerrero, R.; Raso, J.; Anel, A. Production of a Granulysin-Based, Tn-Targeted Cytolytic Immunotoxin Using Pulsed Electric Field Technology. Int. J. Mol. Sci. 2020, 21, 6165. [CrossRef] 19. Guerrero-Ochoa, P.; Ibáñez-Pérez, R.; Berbegal-Pinilla, G.; Aguilar, D.; Marzo, I.; Corzana, F.; Minjárez-Sáenz, M.; Macías-León, J.; Conde, B.; Raso, J.; et al. Preclinical Studies of Granulysin-Based Anti-MUC1-Tn Immunotoxins as a New Antitumoral Treatment. Biomedicines 2022, 10, 1223. [CrossRef] 20. Sanz, L.; Ibáñez-Pérez, R.; Guerrero-Ochoa, P.; Lacadena, J.; Anel, A. Antibody-Based Immunotoxins for Colorectal Cancer Therapy. Biomedicines 2021, 9, 1729. [CrossRef] 21. Shah, P.; Shende, P. Biomacromolecule-Functionalized Nanoparticle-Based Conjugates for Potentiation of Anticancer Therapy. Curr. Cancer Drug Targets 2022, 22, 31–48. [CrossRef] [PubMed] 22. De Miguel, D.; Basáñez, G.; Sánchez, D.; Galán, P.; Marzo, I.; Larrad, L.; Naval, J.; Pardo, J.; Anel, A.; Martinez-Lostao, L. Thethering Apo2L/TRAIL to liposomes overcomes chemoresistance of human hematological tumor cells. Mol. Pharm. 2013, 10, 893–904. [CrossRef] [PubMed] 23. De Miguel, D.; Lemke, J.; Anel, A.; Walczak, H.; Martinez-Lostao, L. Onto better TRAILs for cancer treatment. Cell Death Differ. 2016, 23, 733–747. [CrossRef] [PubMed] 24. Gallego-Lleyda, A.; De Miguel, D.; Anel, A.; Martinez-Lostao, L. Lipid Nanoparticles Decorated with TNF-Related Aptosis- Inducing Ligand (TRAIL) Are More Cytotoxic than Soluble Recombinant TRAIL in Sarcoma. Int. J. Mol. Sci. 2018, 19, 1449. [CrossRef] [PubMed] 25. De Miguel, D.; Gallego-Lleyda, A.; Martinez-Ara, M.; Plou, J.; Anel, A.; Martinez-Lostao, L. Double-Edged Lipid Nanoparticles Combining Liposome-Bound TRAIL and Encapsulated Doxorubicin Showing an Extraordinary Synergistic Pro-Apoptotic Potential. Cancers 2019, 11, 1948. [CrossRef] 26. Guo, Y.; Luan, G.; Shen, G.; Wu, L.; Jia, H.; Zhong, Y.; Li, R.; Li, G.; Shen, Y.; Sun, J.; et al. Production and characterization of recombinant 9 and 15 kDa granulysin by fed-batch fermentation in Pichia pastoris. Appl. Microbiol. Biotechnol. 2013, 97, 7669–7677. [CrossRef] 13 of 13 Int. J. Mol. Sci. 2022, 23, 8705 13 of 13 27. Singh, R.; Letai, A.; Sarosiek, K. Regulation of apoptosis in health and disease: The balancing act of BCL-2 family proteins. Nat. Rev. Mol. Cell Biol. 2019, 20, 175–193. [CrossRef] 28. Cheong, I.; Huang, X.; Thornton, K.; Diaz, L.; Zhou, S. Targeting cancer with bugs and liposomes: Ready, aim, fire. Cancer Res. 2007, 67, 9605–9608. [CrossRef] 29. Ibrahim, M.; Abuwatfa, W.; Awad, N.; Sabouni, R.; Husseini, G. Encapsulation, Release, and Cytotoxicity of Doxorubicin Loaded in Liposomes, Micelles, and Metal-Organic Frameworks: A Review. Pharmaceutics 2022, 14, 254. References [CrossRef] 30. Tarner, I.; Muller-Ladner, U. Drug delivery systems for the treatment of rheumatoid arthritis. Expert Opin. Drug Deliv. 2008, 5, 1027–1037. [CrossRef] 31. Hou, X.; Zaks, T.; Langer, R.; Dong, Y. Lipid nanoparticles for mRNA delivery. Nat. Rev. Mater. 2021, 6, 10 31. Hou, X.; Zaks, T.; Langer, R.; Dong, Y. Lipid nanoparticles for mRNA delivery. Nat. Rev. Mater. 2021, 6, 1078–1094. [CrossRef] [PubMed] 32. Anel, A.; Gallego-Lleyda, A.; de Miguel, D.; Naval, J.; Martinez-Lostao, L. Role of Exosomes in the Regulation of T-cell Mediated Immune Responses and in Autoimmune Disease Cells 2019 8 154 [CrossRef] [PubMed] 32. Anel, A.; Gallego-Lleyda, A.; de Miguel, D.; Naval, J.; Martinez-Lostao, L. Role of Exosomes in the Regulation of T-cell Mediated Immune Responses and in Autoimmune Disease. Cells 2019, 8, 154. [CrossRef] [PubMed] 32. Anel, A.; Gallego-Lleyda, A.; de Miguel, D.; Naval, J.; Martinez-Lostao, L. Role of Exosomes in the Re Immune Responses and in Autoimmune Disease. Cells 2019, 8, 154. [CrossRef] [PubMed] mmune Responses and in Autoimmune Disease. Cells 2019, 8, 154. [CrossRef] [PubMed] p 33. Martínez-Lorenzo, M.J.; Anel, A.; Gamen, S.; Monleón, I.; Lasierra, P.; Larrad, L.; Piñeiro, A.; Alava, M.A.; Naval, J. Activated human T cells release bioactive Fas ligand and APO2 ligand in microvesicles. J. Immunol. 1999, 163, 1274–1281. [PubMed] 34 Naval J ; de Miguel D ; Gallego Lleyda A ; Anel A ; Martinez Lostao L Importance of TRAIL Molecular Anatomy in Receptor g g J 34. Naval, J.; de Miguel, D.; Gallego-Lleyda, A.; Anel, A.; Martinez-Lostao, L. Importance of TRAIL Molecular Anatomy in Receptor Oligomerization and Signaling. Implications for Cancer Therapy. Cancers 2019, 11, 444. [CrossRef] [PubMed] 34. Naval, J.; de Miguel, D.; Gallego-Lleyda, A.; Anel, A.; Martinez-Lostao, L. Importance of TRAIL Mo Oligomerization and Signaling. Implications for Cancer Therapy. Cancers 2019, 11, 444. [CrossRef] 34. Naval, J.; de Miguel, D.; Gallego-Lleyda, A.; Anel, A.; Martinez-Lostao, L. Importance of TRAIL Molecular Anatomy in Receptor Oligomerization and Signaling. Implications for Cancer Therapy. Cancers 2019, 11, 444. [CrossRef] [PubMed] g g y p merization and Signaling. Implications for Cancer Therapy. Cancers 2019, 11, 444. [CrossRef] [PubMed] 35. Ejigah, V.; Owoseni, O.; Bataille-Backer, P.; Ogundipe, O.; Fisusi, F.; Adesina, S. Approaches to Improve Macromolecule and Nanoparticle Accumulation in the Tumor Microenvironment by the Enhanced Permeability and Retention Effect. Polymers 2022, 14, 2601. [CrossRef] [PubMed] 36. Stylianopoulos, T. EPR-effect: Utilizing size-dependent nanoparticle delivery to solid tumors. Ther. Deliv. 42. Martinez-Lostao, L.; García-Alvarez, F.; Basáñez, G.; Alegre-Aguarón, E.; Desportes, P.; Larrad, L.; Naval, J.; Martínez-Lorenzo, M.J.; Anel, A. Liposome-Bound APO2L/TRAIL Is an Effective Treatment in a Rabbit Model of Rheumatoid Arthritis. Arthrit. Rheum. 2010, 62, 2272–2282. [CrossRef] [PubMed] 41. Bosque, A.; Pardo, J.; Martínez-Lorenzo, M.J.; Iturralde, M.; Marzo, I.; Piñeiro, A.; Alava, M.A.; Naval, J.; Anel, A. Down-regulation of normal human T cell blast activation: Roles of APO2L/TRAIL, FasL and c- FLIP, Bim or Bcl-x isoform expression. J. Leukoc. Biol. 2005, 77, 568–578. [CrossRef] [PubMed] References 2013, 4, 421–423. [CrossRef] [PubMed] 37. Kaufmann, S.; Vaux, D. Alterations in the apoptotic machinery and their potential role in anticancer d 2003, 22, 7414–7430. [CrossRef] 38. Merino, D.; Kelly, G.; Lessene, G.; Wei, A.; Roberts, A.; Strasser, A. BH3-Mimetic Drugs: Blazing the Trail for New Cancer Medicines. Cancer Cell 2018, 34, 879–891. [CrossRef] , , [ ] 39. Radha, G.; Raghavan, S. BCL2: A promising cancer therapeutic target. Biochim. Biophys. Acta Rev. Cancer 2017, 1868, 309–314. [CrossRef] 40 B H W l h M L i i G li S D C D ld M G h P Zi l U Ch l l i N i l Ch d 39. Radha, G.; Raghavan, S. BCL2: A promising cancer therapeutic target. Biochim. Biophys. Acta Rev. Cancer 2017, 1868, 309–314. [CrossRef] 40. Barman, H.; Walch, M.; Latinovic-Golic, S.; Dumrese, C.; Dolder, M.; Groscurth, P.; Ziegler, U. Cholesterol in Negatively Charged Lipid Bilayers Modulates the Effect of the Antimicrobial Protein Granulysin. J. Membr. Biol. 2006, 212, 29–39. [CrossRef] 41. Bosque, A.; Pardo, J.; Martínez-Lorenzo, M.J.; Iturralde, M.; Marzo, I.; Piñeiro, A.; Alava, M.A.; Naval, J.; Anel, A. Down-regulation of normal human T cell blast activation: Roles of APO2L/TRAIL, FasL and c- FLIP, Bim or Bcl-x isoform expression. J. Leukoc. Biol. 2005, 77, 568–578. [CrossRef] [PubMed] 42. Martinez-Lostao, L.; García-Alvarez, F.; Basáñez, G.; Alegre-Aguarón, E.; Desportes, P.; Larrad, L.; Naval, J.; Martínez-Lorenzo, M.J.; Anel, A. Liposome-Bound APO2L/TRAIL Is an Effective Treatment in a Rabbit Model of Rheumatoid Arthritis. Arthrit. Rheum. 2010, 62, 2272–2282. [CrossRef] [PubMed]
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Terms of Use This article was downloaded from Harvard University’s DASH repository, and is made available under the terms and conditions applicable to Other Posted Material, as set forth at http:// nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#LAA Permanent link http://nrs.harvard.edu/urn-3:HUL.InstRepos:5332929 Citation Fritsch, Christine, Johan Hoebeke, Hayet Dali, Vincent Ricchiuti, David A Isenberg, Olivier Meyer, and Sylviane Muller. 2006. 52-kDa Ro/SSA epitopes preferentially recognized by antibodies from mothers of children with neonatal lupus and congenital heart block. Arthritis Research & Therapy 8(1): R4. Share Your Story The Harvard community has made this article openly available. Please share how this access benefits you. Submit a story . Accessibility Available online http://arthritis-research.com/content/8/1/R4 Abstract Antibodies to Ro52 peptide 365–382 have been shown previously to cross-react with residues 165– 185 of the heart 5-HT4 serotoninergic receptor, and might be pathologically important. The level of these Ro52 antibody subsets decreased at the end of pregnancy and after delivery. IgG antibodies to Ro52 peptides 1–13, 107–122, 277–292 and 365–382 may therefore represent important biomarkers to predict a complication in pregnant lupus women with Ro52 antibodies. Christine Fritsch1, Johan Hoebeke1, Hayet Dali1, Vincent Ricchiuti1,2, David A Olivier Meyer4 and Sylviane Muller1 1UPR 9021 Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire et Cellulaire, Strasbourg, France 2Division of Endocrinology, Diabetes & Hypertension, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA 3Centre for Rheumatology, The Middlesex Hospital, University College London, UK 4G H it li Bi h t Cl d B d S i d Rh t l i P i F Corresponding author: Sylviane Muller, S.Muller@ibmc.u-strasbg.fr Received: 24 Aug 2005 Revisions requested: 22 Sep 2005 Revisions received: 30 Sep 2005 Accepted: 6 Oct 2005 Published: 4 Nov 2005 Received: 24 Aug 2005 Revisions requested: 22 Sep 2005 Revisions received: 30 Sep 2005 Accepted: 6 Oct 2005 Published: 4 Nov 2005 A th iti R h & Th 2006 8 R4 (d i 10 1186/ 1848) Received: 24 Aug 2005 Revisions requested: 22 Sep 2005 Revisions received: 30 Sep 2005 Accepted: 6 O Arthritis Research & Therapy 2006, 8:R4 (doi:10.1186/ar1848) This article is online at: http://arthritis-research.com/content/8/1/R4 p © 2005 Fritsch et al.; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract differences were found between Sjögren's syndrome and asymptomatic mothers of group I, who had at least one infant with neonatal lupus, and of group II, who had healthy babies only, significant differences were observed between lupus mothers from both groups. In the former group of lupus mothers, a significantly higher frequency of antibodies to Ro52 peptides 107–122 and 277–292 was observed. Between 18 and 30 weeks of gestation, the period of risk, there was clearly an elevated level of antibodies reacting with Ro52 peptides 1–13, 277–292 and 365–382. Antibodies to Ro52 peptide 365–382 have been shown previously to cross-react with residues 165– 185 of the heart 5-HT4 serotoninergic receptor, and might be pathologically important. The level of these Ro52 antibody subsets decreased at the end of pregnancy and after delivery. IgG antibodies to Ro52 peptides 1–13, 107–122, 277–292 and 365–382 may therefore represent important biomarkers to predict a complication in pregnant lupus women with Ro52 antibodies. Neonatal lupus erythematosus is a rare disorder caused by the transplacental passage of maternal autoantibodies. The 52-kDa Ro/SSA antigen (Ro52) ribonucleoprotein represents an antigenic target strongly associated with the autoimmune response in mothers whose children have neonatal lupus and cardiac conduction disturbances, mainly congenital heart block. The objective of this study was to identify putative Ro52/60-kDa Ro/SSA antigen (Ro60) epitopes associated with neonatal lupus and congenital heart block. The reactivity of IgG antibodies present in the sera from mothers with systemic lupus erythematosus and Sjögren's syndrome and in the sera from asymptomatic mothers (a longitudinal study of 192 samples from 66 subjects) was investigated by ELISA using Ro52, Ro60 and 48-kDa La/SSB antigen proteins, as well as 45 synthetic peptides, 13–24 residues long, of Ro52/Ro60 proteins. One to 19 samples collected before, during and after pregnancy were available for each mother. Forty-three disease controls selected randomly and normal sera were tested in parallel. Although no differences were found between Sjögren's syndrome and asymptomatic mothers of group I, who had at least one infant with neonatal lupus, and of group II, who had healthy babies only, significant differences were observed between lupus mothers from both groups. In the former group of lupus mothers, a significantly higher frequency of antibodies to Ro52 peptides 107–122 and 277–292 was observed. Between 18 and 30 weeks of gestation, the period of risk, there was clearly an elevated level of antibodies reacting with Ro52 peptides 1–13, 277–292 and 365–382. CHB = congenital heart block; ELISA = enzyme-linked immunosorbent assay; 5-HT4-R, 5-HT4 receptor; La, 48-kDa La/SSB antigen; NLE, neonatal lupus erythematosus; OD, optical density; Ro52, 52-kDa Ro/SSA antigen; Ro60, 60-kDa Ro/SSA antigen; SLE, systemic lupus erythematosus; SS, Sjögren's syndrome. Patients and methods Patients Two groups of mothers were defined in this study (Table 1). Group I was composed of 41 consecutive mothers who gave birth to 58 children, of whom at least one infant per mother was affected with NLE. In this group, 10 mothers had a lupus, 15 mothers had SS and 16 mothers were asymptomatic. Among the 58 children of these 41 mothers, 45 children had a CHB (14 males, 18 females, 13 unknowns), five children had a cutaneous NLE (one male, four females), and eight children were healthy (three males, four females, one unknown). The diagnosis of complete CHB was based on fetal echocardiog- raphy when the diagnosis of CHB was obtained during fetal life, and was based on postnatal electrocardiogram when bradycardia was detected. Among the 41 mothers who gave birth to a child with NLE, four had a pregnancy that resulted in at least one abortion after an in utero fetal demise or early death of a baby younger than 6 months. These 41 mothers were aged 19–56 years (average 32.9 years) when their blood was collected, for some of them a long period of time after pregnancy (maximum 12 years). Group II corresponded to 25 mothers with 30 healthy children. In this group, 18 mothers had a lupus and seven mothers had an SS, the mothers were aged 23–42 years (average 33.6 years) and three abortions occurred. Patients selected in our study mainly presented rheumatological and dermatological manifestations. The association of CHB with maternal autoantibodies to Ro and La antigens might be due to cross-reactions between maternal anti-Ro/La antibodies and fetal cardiac-specific anti- gens. A possible antigen targeted by La antibodies might be laminin, a major component of the sarcolemmal membrane of cardiomyocytes, which undergoes conformational changes during development (residues EAKLRA are common to La and B1 laminin) [10,11]. Molecular mimicry between these two self-antigens could thus contribute to the pathogenesis of CHB at an early stage during fetal cardiac development. We have more recently identified a cross-reactive B-cell epitope between the Ro52 protein (in residues 365–382) and the heart 5-HT4 serotoninergic receptor (residues 165–185), and have demonstrated that these cross-reactive antibodies antagonized the serotonin-induced L-type Ca2+ channel acti- vation on human atrial cells [12]. Introduction ble. In contrast, noncardiac manifestations are transient, resolving by 1 year of age without specific treatment [1]. The mothers of these children often have an autoimmune disorder (i.e. systemic lupus erythematosus [SLE] and/or Sjögren's syndrome [SS]), with antibodies against SSA/Ro and/or SSB/ La antigens. However, entirely asymptomatic mothers with these antibodies (generally diagnosed after delivery) can also Neonatal lupus erythematosus (NLE) is a rare, but severe, pas- sively acquired autoimmune syndrome of neonates character- ized by cardiac, dermatological, hepatic and hematological manifestations. Autoimmune-associated congenital heart block (CHB) is often detected between 18 and 24 weeks of gestation and, to date, in its complete form, remains irreversi- CHB = congenital heart block; ELISA = enzyme-linked immunosorbent assay; 5-HT4-R, 5-HT4 receptor; La, 48-kDa La/SSB antigen; NLE, neonatal lupus erythematosus; OD, optical density; Ro52, 52-kDa Ro/SSA antigen; Ro60, 60-kDa Ro/SSA antigen; SLE, systemic lupus erythematosus; SS, Sjögren's syndrome. Page 1 of 11 (page number not for citation purposes) Page 1 of 11 (page number not for citation purposes) Arthritis Research & Therapy Vol 8 No 1 Fritsch et al. heart [14]. The expression of 5-HT4-R in the human fetal heart has also been confirmed [15]. give birth to infants with CHB. Maternal antibodies to the 52- kDa Ro/SSA (Ro52) and 48-kDa La/SSB (La) antigens have been reported to be more strongly associated with CHB than antibodies to the 60-kDa (Ro60) alone [2,3]. The prevalence of CHB in newborns of prospectively followed women with anti-SSA antibodies and known autoimmune rheumatic dis- ease is 2% [4]. give birth to infants with CHB. Maternal antibodies to the 52- kDa Ro/SSA (Ro52) and 48-kDa La/SSB (La) antigens have been reported to be more strongly associated with CHB than antibodies to the 60-kDa (Ro60) alone [2,3]. The prevalence of CHB in newborns of prospectively followed women with anti-SSA antibodies and known autoimmune rheumatic dis- ease is 2% [4]. Although many questions remain to be solved to understand the involvement of 5-HT4-R in the pathogenicity of CHB, the quest for biomarkers that predict mothers at risk remains an important challenge. Introduction In this study, we have tested the sera from 66 mothers (a longitudinal study of 192 samples) in dif- ferent clinical subgroups for the presence in their serum of IgG antibodies reacting with Ro52, Ro60 and La proteins, as well as with 39 synthetic peptides covering the whole sequence of the Ro52 protein and with six peptides of the Ro60 protein. The appearance of protein and peptide-reactive antibodies was examined regularly in mothers before, during and after delivery. The aim of this study was twofold; first, to determine whether antibodies to the Ro52 peptide 365–382 are impor- tant in predicting a complication in pregnant women with Ro antibodies; and, second, to identify other putative Ro52 epitopes associated with neonatal lupus and CHB. Several lines of evidence support the pathogenic role of Ro and La antibodies, which presumably cross the placenta and damage the conduction system of the developing fetus. It is notable, however, that abnormalities are not detectable in maternal cardiac functions despite exposure to the identical antibodies. The pathogenic role of maternal antibodies is poorly understood. Direct implication of Ro/La antibodies has been described in two studies of fatal CHB. Maternal IgG bearing anti-La idiotypes were identified on the surface of fetal cardiac myocytes [5] and Ro antibodies were found in an affected fetal heart [6]. In addition, complete atrioventricular block could be induced in the rabbit and human fetal heart after perfusion of the aorta with anti-Ro52 antibodies [7,8]. These same antibodies inhibited the whole-cell and single- channel L-type Ca2+ channels. The pathogenic role of Ro52 antibodies in the development of CHB was also supported by an experiment using BALB/c mice as a murine model [9]. Page 2 of 11 (page number not for citation purposes) ELISA, immunodiffusion and Western blotting From each mother of groups I and II, 1–19 serum samples were available to study. A total of 192 sera from mothers were tested all together. All of the women gave informed consent to participate, and the study was approved by the Ethics Com- mittee at the Paris Bichat-Claude Bernard Hospital. Disease controls were studied in addition, including the serum from patients with SLE (n = 14), with SS (n = 15) and with rheuma- toid arthritis (RA; n = 14) selected randomly (women without indication of pregnancy), and the sera from 24 healthy blood donors were also tested. Lupus patients' sera were randomly taken from the serum collection from one of the authors (DAI) and no pre-selection according to disease manifestation or severity was made. The global score (British Isles Lupus Assessment Group system) used to measure the lupus dis- ease severity of 14 female patients (aged 17–58 years; aver- age 28.4 years) was between 1 and 22 (inactive/mildly active disease, score 1–5, n = 6; moderately to severely active dis- ease, score 6 or greater, n = 8). Eight of these patients were Caucasian, four patients were Afro-Caucasian and two patients were Chinese. Informed consent was obtained from all participants in accordance with the medical ethical regula- tions of the local committee. Sera were stored at -70°C until use. The methods used for testing antibodies reacting with rRo52, Ro60 and La proteins in the three types of assay and Ro52/ Ro60 peptides in ELISA have been previously described [16,17]. Only the IgG response was tested in the ELISA and Western blotting assay. Peptides were found to be satisfacto- rily attached to the plastic surface of ELISA plates using anti- bodies induced in rabbits against these peptides [18]. For calculations, all optical density (OD) values >3 measured in the ELISA were considered as 3.0. The cutoff points of each assay were determined from a series of sera collected from 24 normal donors using the mean OD values of these normal sera tested in parallel + 2 standard deviations. For convenience, the 192 sera screened with the 48 antigens (proteins and peptides) were considered positive when OD ≥0.3. When this threshold value was used, none of the normal sera was found positive. Mean OD values correspond to the arithmetic mean of all OD values, including values under the cutoff line for pos- itivity. Patients and methods Patients Further studies showed that antibodies against the human 5-HT4 receptor (5-HT4-R) have no intrinsic activity on the receptor itself but block receptor activation on human atrial cells by the cognate hormone sero- tonin [13]. Most importantly, it was also demonstrated that pups from normal female mice immunized with the 5-HT4-R peptide 165–185 showed bradycardia, atrioventricular blocks of type I and type II, longer QT intervals, skin rash and neuro- motoric problems [14]. We have thus clearly demonstrated that anti-5-HT4-R antibodies are associated with neonatal lupus, that they are pathogenic and that they cross-react with the Ro52 antigen [12-14]. It is notable that while the 5-HT4-R is not functional in adult rodents, it is expressed in mouse fetal For patients with SLE, the symptoms were usually mild to mod- erately severe, and generally no treatment was necessary by the time surrounding pregnancy. Those who needed to be treated were well controlled by either corticosteroids (about 5–20 mg/day Cortancyl®) or hydroxychloroquine (Plaquenil®). The latter was in most cases interrupted during pregnancy. Only a few mothers (3/22 documented lupus mothers) required a more aggressive treatment such as Page 2 of 11 (page number not for citation purposes) Available online http://arthritis-research.com/content/8/1/R4 Table 1 Table 1 Table 1 Description of the study groups Symptom Group I Group II Total Mothers Children Mothers Children Mothers Children Systemic lupus erythematosus 10 (24) 13 18 (91) 21 28 (115) 34 Sjögren's syndrome 15 (17) 26 7 (40) 9 22 (57) 35 Asymptomatic 16 (20) 19 0 0 16 (20) 19 Total 41 (61) 58 25 (131) 30 66 (192) 88 Numbers in parentheses indicate the number of serum samples tested in each group. Description of the study groups Numbers in parentheses indicate the number of serum samples tested in each jugated to ovalbumin through the -SH group of cysteine 38 using m-maleimido benzoyl-N-hydroxy succinimide ester as a coupling agent [17]. cyclophosphamide (Endoxan®), which was replaced by corti- costeroids during pregnancy. Plasmapheresis was realized to prevent CHB when the risk was high. Aspirin was introduced during pregnancy to prevent the risk of thrombosis. ELISA, immunodiffusion and Western blotting Statistically significant frequency differences between groups were determined by Student's t test. Mean OD values differences between groups were analyzed using the Mann- Whitney U test. P < 0.05 was considered significant. Page 3 of 11 (page number not for citation purposes) Table 2 Thus, for each mother, the frequency of positivity (%) to each peptide was determined as the number of positive sera reported to the total number of samples. quently detected in the serum from patients with SLE and SS than in the serum from asymptomatic mothers (Table 2). Inter- estingly most of the sera from SLE, SS and asymptomatic mothers contained antibodies reacting with both Ro52 and Ro60. Very few sera contained antibodies reacting with only one Ro protein (or with La only; data not shown), and this reac- tivity profile was consistently observed in mothers of both groups I and II. No statistically significant difference was observed between the sera of groups I and II when the reac- tivity of sera with the Ro52 and Ro60 proteins was examined. peptide 277–292 (83% versus 49%; P = 0.049) and to Ro60 peptide 21–41 (64% versus 27%, P = 0.044) was more fre- quently elevated in the serum from mothers of group I. These differences were statistically significant with P ≤ 0.050. Some peptides were recognized much more frequently by the anti- bodies from mothers of group I, although in a non-statistically significant manner; for example, with the Ro52 peptide 107– 126 (37% versus 7%; P = 0.062) and the Ro52 peptide 365– 382 (77% versus 47%; P = 0.054). quently detected in the serum from patients with SLE and SS than in the serum from asymptomatic mothers (Table 2). Inter- estingly most of the sera from SLE, SS and asymptomatic mothers contained antibodies reacting with both Ro52 and Ro60. Very few sera contained antibodies reacting with only one Ro protein (or with La only; data not shown), and this reac- tivity profile was consistently observed in mothers of both groups I and II. No statistically significant difference was observed between the sera of groups I and II when the reac- tivity of sera with the Ro52 and Ro60 proteins was examined. It is noticeable that in contrast to what was observed with the sera from lupus mothers, the sera from mothers with SS reacted with fewer Ro peptides; namely, four Ro52 peptides (sequences 1–13, 107–122, 277–292 and 365–382) and two Ro60 peptides (sequences 21–41 and 304–324), which were recognized by at least 25% of sera. The percentage of sera positive with these peptides in groups I and II was not sta- tistically significantly different (Table 3). Ro proteins and Ro synthetic peptides Affinity-purified Ro60 and La proteins were obtained from Immunovision (ref. SSA-300; Springdale, AR, USA). The pro- duction and purification of human recombinant Ro52 (rRo52), a kind gift from G Pruijn and W van Venrooij (Nijmegen, The Netherlands), has been described previously [16]. Synthesis and purification of 39 overlapping peptides of Ro52 and of six peptides of Ro60 have been described previously [16,17]. Ro52 peptides encompassed 13–24 amino acid residues and, in general, overlapped each other by 1–10 residues. Selection of peptides that have been synthesized have also been made according to difficulties of synthesis and/or solu- bility in aqueous solvents. The Ro60 peptide 21–41 was con- The sera from mothers with SLE and SS as well as sera from asymptomatic mothers were tested with Ro proteins by immu- nodiffusion, Western blotting and ELISA. Previous studies have shown that distinct antibody subsets are identified using these different immunoassays [16]. This observation was con- firmed in the present study (Table 2). In general, the ELISA detected Ro52 and Ro60 antibodies in a higher number of sera than Western blotting. A number of sera were positive in immunodiffusion tests but negative in ELISA and/or Western blotting tests. Conversely, some immunodiffusion-negative sera were positive in the ELISA and/or Western blotting tests. It is noticeable, however, that Ro antibodies were more fre- Page 3 of 11 (page number not for citation purposes) Arthritis Research & Therapy Vol 8 No 1 Fritsch et al. Arthritis Research & Therapy Vol 8 No 1 Fritsch et al. Page 4 of 11 (page number not for citation purposes) Table 2 Table 2 Reactivity in different tests of sera from mothers of groups I and II Mothers Immunodiffusion Western blotting ELISA Ro (%) Ro52 (%) Ro60 (%) Ro52 (%) Ro60 (%) Systemic lupus erythematosus Group I (n = 9 mothers; 12 samples) 25 67 25 92 67 Group II (n = 14 mothers; 26 samples) 69 12 23 62 69 Total (n = 23 mothers; 38 samples) 47 39 24 77 68 Sjögren's syndrome Group I (n = 14 mothers; 14 samples) 71 57 29 64 64 Group II (n = 6 mothers; 12 samples) 100 50 25 100 100 Total (n = 20 mothers; 26 samples) 86 54 27 82 82 Asymptomatic Group I (n = 13 mothers; 13 samples) 38 23 8 31 38 The results are shown for mothers, the serum of whom has been systematically tested in the three assays. Only the IgG antibody response was tested in Western blotting and ELISA. The first figure in parentheses represents the number of mothers and the second represents the total number of samples tested. The data take into account the number of samples collected from each mother, which differs from 1 to 5. Thus, for each mother, the frequency of positivity (%) to each peptide was determined as the number of positive sera reported to the total number of samples. Reactivity in different tests of sera from mothers of groups I and II The results are shown for mothers, the serum of whom has been systematically tested in the three assays. Only the IgG antibody response was tested in Western blotting and ELISA. The first figure in parentheses represents the number of mothers and the second represents the total number of samples tested. The data take into account the number of samples collected from each mother, which differs from 1 to 5. Thus, for each mother, the frequency of positivity (%) to each peptide was determined as the number of positive sera reported to the total number of samples. The results are shown for mothers, the serum of whom has been systematically tested in the three assays. Only the IgG antibody response was tested in Western blotting and ELISA. The first figure in parentheses represents the number of mothers and the second represents the total number of samples tested. The data take into account the number of samples collected from each mother, which differs from 1 to 5. Table 2 The 192 sera from 41 mothers of group I and from 25 mothers of group II were then tested for their ability to react in the ELISA with 39 overlapping peptides covering the whole Ro52 sequence and with six Ro60 peptides. The reactivity of autoim- mune sera with these 45 peptides has been described previ- ously [16,17,19]. The data (frequency and P values) presented in Table 3 take into account the number of samples collected from each mother that differs from 1 to 19. The anal- ysis of data showed that, among the 45 peptides tested in ELISA, only three (sequences 191–208, 262–279 and 326– 340 of Ro52) were never recognized by IgG antibodies con- tained in the sera of groups I and II. Thirty-one other peptides were recognized by less than 25% of sera, and 11 peptides were recognized by at least 25% of sera (Table 3). The sera from asymptomatic mothers with affected children collected 3 months-10 years after delivery (mean 4.8 years) reacted weakly and infrequently with Ro52 and Ro60 peptides (Table 3). The reactivity of sera with La protein follows the same pattern of reactivity; namely, a highly significant elevation of positive sera from lupus mothers of group I as compared with lupus mothers of group II, positivity of sera from mothers with SS that was not statistically different in groups I and II, and a low frequency of positive sera in the group of asympto- matic mothers of group I (Table 3). When the reactivity of SLE sera was analyzed and compared in both groups I and II, we observed first that the spectrum of reactivity of antibodies from mothers of group I was larger (11 peptides versus 5 peptides recognized by at least 25% of sera). Table 2 Arthritis Research & Therapy Vol 8 No 1 Fritsch et al. 436–451 CAFTGPLRPFFSPGFN 13 7 13 10 0 447–463 SPGFNDGGKNTAPLTLC 8 9 0 6 0 463–475 CPLNIGSQGSTDY 0 7 7 1 0 Ro60 PROTEIN 80 67 67 99 0.022* 31 1–23 MEESVNQMQPLNEKQIANSQDGY 15 6 17 1 6 18–38 NSQDGYVWQVTDMNRLHRFLC 32 11 20 1 0.097 0 21–41 DGYVWQVTDMNRLHRFLCFGS 64 27 0.044* 23 38 0 304–324 VCEKLCNEKLLKKARIHPFHI 50 18 27 4 13 495–518 KLIVCGMTSNGFTIADPDDRGMLD 10 24 0.058 7 11 0.079 13 524–538 TGALDVIRNFTLDMI 10 17 3 9 0 La PROTEIN 93 30 <0.00 01* 40 68 13 The 192 samples described in Table 1 were systematically tested in at least two independent tests. Only the IgG response was tested. Patients' sera were diluted 1:1,000. To be tested in the ELISA, peptide 21–41 of Ro60 protein was conjugated to ovalbumin. The sera were considered positive when optical density ≥0.3. Statistically significant differences between groups were determined by Student's t test. *P < 0.05 considered significant. Table 3 (Continued) Reactivity in ELISA of sera from mothers of groups I and II The 192 samples described in Table 1 were systematically tested in at least two independent tests. Only the IgG response was tested. Patients' sera were diluted 1:1,000. To be tested in the ELISA, peptide 21–41 of Ro60 protein was conjugated to ovalbumin. The sera were considered positive when optical density ≥0.3. Statistically significant differences between groups were determined by Student's t test. *P < 0.05 considered significant. antigens (Ro52, Ro60, La proteins and the 45 peptides of Ro52 and Ro60) was then examined in serial samples from lupus mothers of groups I and II in order to establish, in a more individual manner, whether correlations exist between the presence of these antibody subsets and different parameters related to the disease, the treatment and the course of preg- nancy. Figure 1 shows longitudinal testing of sera from four representative mothers. Table 2 In summary, the most significant differences observed between mothers of groups I and II were in lupus mothers of group I, who possessed a significantly higher frequency of IgG antibodies to Ro52 peptides 107–122 and 277–292 and to Ro60 peptide 21–41. In a series of disease control sera col- lected from randomly selected patients with SLE, SS and RA, the data showed that, in good agreement with our previous results, the two Ro52 peptides were not recognized or were recognized infrequently [16,19] by the sera from these patients. In summary, the most significant differences observed between mothers of groups I and II were in lupus mothers of group I, who possessed a significantly higher frequency of IgG antibodies to Ro52 peptides 107–122 and 277–292 and to Ro60 peptide 21–41. In a series of disease control sera col- lected from randomly selected patients with SLE, SS and RA, the data showed that, in good agreement with our previous results, the two Ro52 peptides were not recognized or were recognized infrequently [16,19] by the sera from these patients. Table 2 The cumulative data are reported in Figure 2, in which we have subdivided the analysis into three periods: before pregnancy (in a range of 18 months with a mean at 11 weeks for group I, and in a range of 21 months with a mean at 48 weeks for group II; Figure 2a,d), during preg- nancy (Figure 2b,e) and after pregnancy (in a range of 26 months with a mean at 21 weeks for the group I, and in a range of 12 months with a mean at 17 weeks for the group II; Figure 2c,f). In a general manner, whichever period is examined and for most of the antibody specificities, the level of IgG antibod- ies (expressed as mean OD values) and their frequency (%) were clearly higher in the mothers of group I as compared with mothers of group II. This observation is true for antibodies reacting with several Ro peptides and for the antibodies to whole Ro proteins (most particularly for La and Ro52 antibod- ies). Before pregnancy, the levels of antibodies to Ro52 pep- tides 277–292 and 365–382 (in terms of mean OD values) as well as Ro52 peptides 1–13, 107–122 and 107–126 (in terms of frequency) were particularly elevated in group I. Dur- ing pregnancy the same antibodies except the antibodies to Ro52 peptide 107–126 were also elevated, and after preg- nancy antibodies to Ro52 peptides 277–292 and 365–382 were elevated. account the number of serum samples available for each mother, very similar results were obtained. Between group I (n = 10) and group II (n = 18) of mothers with lupus, statistically different reactivities were found with Ro52 peptide 107–122 (88% versus 33%, P = 0.011), peptide 277–292 (100% ver- sus 44%, P = 0.007) and peptide 365–382 (100% versus 61%, P = 0.039), and with Ro60 peptide 21–41 (75% versus 33%, P = 0.049) and peptide 304–324 (75% versus 33%, P = 0.049). Reactivities with recombinant Ro52 protein (100% versus 78%), Ro52 peptide 1–13 (88% versus 56%) and La protein (100% versus 50%) were no longer statistically differ- ent between groups I and II of lupus patients. No difference was observed between groups I and II of mothers with SS. Table 2 Second, we found that the level of IgG antibodies to Ro52 peptide 107–122 (69% versus 28%; P = 0.023) and If we considered a mother positive when at least one of sam- ples was positive with a given peptide, instead of taking into Page 4 of 11 (page number not for citation purposes) Available online http://arthritis-research.com/content/8/1/R4 Available online http://arthritis-research.com/content/8/1/R4 Table 3 Table 3 Reactivity in ELISA of sera from mothers of groups I and II Antigen Systemic lupus erythematosus Sjögren's syndrome Asymptoma Group I (%) Group II (%) P Group I (%) Group II (%) P Group I (%) Recombinant Ro52 protein 97 66 0.009* 67 98 0.027* 31 1–13 MASAARLTMMWEE 77 46 0.084 47 58 31 10–25 MWEEVTPICLDPFVE 0 14 0 0 0 12–35 EEVTCPICLDPFVEPVSIECGHSF 10 16 20 8 13 25–40 EPVSIECGHSFCQECI 0 13 10 0 6 34–56 SFCQECISQVGKGGGSVCAVCRQ 0 1 7 0 13 38–53 ECISQVGKGGGSVCAV 3 4 7 0 0 50–64 VCAVCRQRFLLKNLR 25 3 13 5 6 63–79 LRPNRQLANMVNNLKEI 0 6 0 3 0 77–94 KEISQEAREGTQGERCAV 18 1 3 0 0 93–116 AVHGERLHLFCEKDGKALCWVCAQ 40 12 10 9 0 94–109 VHGERLHLFCEKDGKA 3 13 0 0 0 107–122 GKALCWVCAQSRKHRD 69 28 0.023* 47 33 13 107–126 GKALCWVCAQSRKHRDHAMV 37 7 0.062 13 8 13 121–137 RDHAMVPLEEAAQEYQE 0 4 0 0 0 135–151 YQEKLQVALGELRRKQE 3 14 0 0 0 149–166 KQELAEKLEVEIAIKRAD 0 12 0 1 0 164–180 RADWKKTVETQKSRIHA 0 9 0 0 6 178–193 IHAEFVQQKNFLVEEE 3 14 0 0 0 191–208 EEEQRQLQELEKDEREQL 0 0 0 0 0 206–224 EQLRILGEKEAKLAQQSQA 0 1 7 0 9 222–235 SQALQELISELDRRCHS 17 3 23 1 6 236–250 CHSSALELLQEVIIV 27 6 10 7 0 249–264 IVLERSESWNLKDLDI 0 5 7 0 0 262–279 LDITSPELRSVCHVPGLK 0 0 0 0 0 277–292 GLKKMLRTCAVHITLD 83 49 0.049* 40 24 6 290–304 TLDPDTANPWLILSE 0 7 7 0 0 302–317 LSEDRRQVRLGDTQQS 10 2 7 0 0 314–328 TQQSIPGNEERFDSY 0 9 0 9 0 326–340 DSYPMVLGAQHFHSG 0 0 0 0 0 337–352 FHSGKHYWEVDVTGKE 23 11 3 12 6 350–367 GKEAWDLGVCRDSVRRKG 0 1 0 0 9 365–382 RKGHFLLSSKSGFWTIWL 77 47 0.054 50 33 25 380–396 IWLWNKQKYEAGTYPQT 0 5 0 2 0 394–412 PQTPLHLQVPPCQVGIFLD 18 1 3 10 0 411–423 LDYEAGMVSFYNI 0 2 0 0 0 422–438 NITDHGSLIYSFSECAF 16 2 0 0 0 Reactivity in ELISA of sera from mothers of groups I and II g (page number not for citation purposes) Arthritis Research & Therapy Vol 8 No 1 Fritsch et al. Page 6 of 11 (page number not for citation purposes) I and II All samples were systematically tested in at least two independent tests – the results shown in the figure correspond to one complete representative experiment. The sera were considered positive when the optical density (OD) values were ≥0.3 (horizon- tal lane). All sera were tested with the 48 antigens. Only the Ro antigens showing the highest reactivity are depicted in the figures; ◆, recombinant Ro52; ■, Ro52 peptide 1–13; •, Ro52 peptide 107–122; š, Ro52 peptide 277–292; ❍, Ro52 peptide 365–382; ▲, La. Longitudinal study of sera from lupus mothers of groups I and II with Ro antigens Longitudinal study of sera from lupus mothers of groups I and II with Ro antigens. The sera from lupus mothers of (a) group I and (b)–(d) group II were tested by ELISA before (b), during (g, for gestation) and after (p, for post) pregnancy. The number of weeks is indicated. Mother D had two consecutive pregnancies (D1 and D2). The rectangles represent the period known to be at risk (approximately weeks 16–26 of gestation), knowing that autoimmune-associated congenital heart block most often occurs between 18 and 24 weeks of gestation. Sera were tested at a 1:1,000 dilu- tion. Only the IgG response was evaluated. All samples were systematically tested in at least two independent tests – the results shown in the figure correspond to one complete representative experiment. The sera were considered positive when the optical density (OD) values were ≥0.3 (horizon- tal lane). All sera were tested with the 48 antigens. Only the Ro antigens showing the highest reactivity are depicted in the figures; ◆, recombinant Ro52; ■, Ro52 peptide 1–13; •, Ro52 peptide 107–122; š, Ro52 peptide 277–292; ❍, Ro52 peptide 365–382; ▲, La. sequentially during her pregnancy. The mother gave birth to a healthy child. In Figure 3, the analysis was further focused on the pregnancy period and the data were examined by defining four testing periods: weeks 1–8, weeks 16–20, weeks 26–30 and weeks 31–35 of pregnancy. Seven samples from five mothers and 24 samples from 17 mothers were examined for group I and group II, respectively. I and II The major features of this study were that the overall level of antibodies was higher in the mothers of group I as compared with group II, and that between 16 and 30 weeks of gestation, the period of risk, there was clearly an elevated level of antibodies reacting with Ro52 peptides 1– 13, 277–292 and 365–382. I and II The data already described indicate that certain antibody sub- types occur more frequently in the serum of lupus mothers of children with NLE than in the samples from lupus mothers with healthy children. The appearance of IgG antibodies to Ro Page 6 of 11 (page number not for citation purposes) Available online http://arthritis-research.com/content/8/1/R4 Figure 1 Figure 1 Longitudinal study of sera from lupus mothers of groups I and II with Ro antigens Longitudinal study of sera from lupus mothers of groups I and II with Ro antigens. The sera from lupus mothers of (a) group I and (b)–(d) group II were tested by ELISA before (b), during (g, for gestation) and after (p, for post) pregnancy. The number of weeks is indicated. Mother D had two consecutive pregnancies (D1 and D2). The rectangles represent the period known to be at risk (approximately weeks 16–26 of gestation), knowing that autoimmune-associated congenital heart block most often occurs between 18 and 24 weeks of gestation. Sera were tested at a 1:1,000 dilu- tion. Only the IgG response was evaluated. All samples were systematically tested in at least two independent tests – the results shown in the figure correspond to one complete representative experiment. The sera were considered positive when the optical density (OD) values were ≥0.3 (horizon- tal lane). All sera were tested with the 48 antigens. Only the Ro antigens showing the highest reactivity are depicted in the figures; ◆, recombinant Ro52; ■, Ro52 peptide 1–13; •, Ro52 peptide 107–122; š, Ro52 peptide 277–292; ❍, Ro52 peptide 365–382; ▲, La. Longitudinal study of sera from lupus mothers of groups I and II with Ro antigens Longitudinal study of sera from lupus mothers of groups I and II with Ro antigens. The sera from lupus mothers of (a) group I and (b)–(d) group II were tested by ELISA before (b), during (g, for gestation) and after (p, for post) pregnancy. The number of weeks is indicated. Mother D had two consecutive pregnancies (D1 and D2). The rectangles represent the period known to be at risk (approximately weeks 16–26 of gestation), knowing that autoimmune-associated congenital heart block most often occurs between 18 and 24 weeks of gestation. Sera were tested at a 1:1,000 dilu- tion. Only the IgG response was evaluated. Discussion The antigenic structure of Ro52, Ro60 and La has been exten- sively studied by several independent groups, and a number of dominant epitopes have been identified in these proteins [20- 22]. However, probably because the number of available sera is relatively low, there are very few systematic mapping studies aimed at the characterization of particular regions of Ro and La antigens recognized by CHB-associated antibodies from mothers of affected infants or, in this context, from children suf- fering from NLE [11,23]. Studies with Ro antigens reported the reactivity of selected sera with recombinant fragments tested by ELISA and Western blotting assay, and it was found that anti-Ro reactivity in mothers of infants with CHB reacted mainly against the Ro52 sequence 200–239, whereas the predominant activity in control mothers was against the sequence 176–196 [23]. This result was confirmed with syn- thetic peptides, and the most recent study demonstrated that pups born from rats immunized with the Ro52 peptide 200– 239 developed atrioventricular block [24]. In the present One of our patients with high levels of IgG antibodies reacting with Ro60, rRo52, Ro52 peptides 1–13, 107–122, 277–292 and 365–382, and Ro60 peptide 21–41 was treated by plas- mapheresis. This lupus mother had a first baby with CHB. Plasmapheresis was used for her second pregnancy as a method of treatment aimed at removing antibodies from her plasma to decrease potential autoimmune activity after placen- tal passage. IgG antibodies were efficiently removed from the bloodstream as measured in serum samples collected Page 7 of 11 (page number not for citation purposes) Page 7 of 11 (page number not for citation purposes) Arthritis Research & Therapy Vol 8 No 1 Fritsch et al. Figure 2 Reactivity in ELISA of sera from lupus mothers of groups I and II with Ro antigens Reactivity in ELISA of sera from lupus mothers of groups I and II with Ro antigens. Sera were classified into three subgroups: (a), (d) before, (b), (e) during, and (c), (f) after pregnancy. The results are expressed in terms of frequency (%) of positive reaction ((a)–(c)) and antibody level (mean optical density [OD] values + standard deviation) ((d)–(f)). Mothers' sera were tested at a 1:1,000 dilution and the IgG response only was evaluated. Discussion The number of samples (number of mothers) was as follows; group I (black bars): (a)–(d), 5 (3); (b)–(e), 8 (5); (c)–(f), 6 (5); group II (white bars): (a)–(d), 18 (4); (b)–(e), 44 (16); (c)–(f), 12 (7). All samples were systematically tested in at least two independent tests. The results shown in the figure cor- respond to one complete representative experiment. The sera were considered positive when OD ≥0.3 (visualized by a longitudinal lane in panels (d)–(f)). All sera were tested with the 48 antigens. Only the Ro antigens showing reactivity are depicted. For clarity, the first residue of each peptide sequence is indicated in the figures (107-1 for 107–122; 107-2 for 107–126). (a)–(c) Student's t test, *0.05 > P > 0.01, **P ≤ 0.01; (d) and (e) Mann-Whitney U test, *0.05 > P > 0.005, **P ≤ 0.005. Reactivity in ELISA of sera from lupus mothers of groups I and II with Ro antigens Reactivity in ELISA of sera from lupus mothers of groups I and II with Ro antigens. Sera were classified into three subgroups: (a), (d) before, (b), (e) during, and (c), (f) after pregnancy. The results are expressed in terms of frequency (%) of positive reaction ((a)–(c)) and antibody level (mean optical density [OD] values + standard deviation) ((d)–(f)). Mothers' sera were tested at a 1:1,000 dilution and the IgG response only was evaluated. The number of samples (number of mothers) was as follows; group I (black bars): (a)–(d), 5 (3); (b)–(e), 8 (5); (c)–(f), 6 (5); group II (white bars): (a)–(d), 18 (4); (b)–(e), 44 (16); (c)–(f), 12 (7). All samples were systematically tested in at least two independent tests. The results shown in the figure cor- respond to one complete representative experiment. The sera were considered positive when OD ≥0.3 (visualized by a longitudinal lane in panels (d)–(f)). All sera were tested with the 48 antigens. Only the Ro antigens showing reactivity are depicted. For clarity, the first residue of each peptide sequence is indicated in the figures (107-1 for 107–122; 107-2 for 107–126). (a)–(c) Student's t test, *0.05 > P > 0.01, **P ≤ 0.01; (d) and (e) Mann-Whitney U test, *0.05 > P > 0.005, **P ≤ 0.005. Page 8 of 11 (page number not for citation purposes) Discussion The IgG response only was evaluated. The sera were considered positive when OD ≥0.3 (horizontal lane). All sera were tested with the 48 antigens. Only the Ro antigens showing reactivity are depicted in the figures. Antigens tested: columns 1, 6 and 9 (black bars), recombinant Ro52, Ro60 and La proteins, respectively; columns 2–5 (grey bars), Ro52 peptides 1–13, 107–122, 277–292 and 365–382; columns 7 and 8, Ro60 peptides 21– 41 and 304–324. Reactivity in ELISA of sera collected from lupus mothers of groups I and II during pregnancy Reactivity in ELISA of sera collected from lupus mothers of groups I and II during pregnancy. Sera were classified in four subgroups, corresponding to weeks 1–8, 16–20, 26–30 and 31–35 of gestation. The number of sera in each subgroup is indicated (n). Sera were tested at a 1:1,000 dilution. The IgG response only was evaluated. The sera were considered positive when OD ≥0.3 (horizontal lane). All sera were tested with the 48 antigens. Only the Ro antigens showing reactivity are depicted in the figures. Antigens tested: columns 1, 6 and 9 (black bars), recombinant Ro52, Ro60 and La proteins, respectively; columns 2–5 (grey bars), Ro52 peptides 1–13, 107–122, 277–292 and 365–382; columns 7 and 8, Ro60 peptides 21– 41 and 304–324. envisaged study will be to evaluate the reactivity of mother's sera with overlapping La peptides. ity of sera with the whole proteins Ro52, Ro60 and La was high in subgroups of SLE and SS mothers and did not help to distinguish the group of mothers at risk, the overall level of IgG antibodies reacting with several Ro peptides, however, was significantly higher in lupus mothers of group I as compared with group II. These peptides encompass residues 107–122 and 277–292 of Ro52 and residues 21–41 of Ro60. Antibod- ies reacting with Ro52 peptides 1–13 and 365–382 were also particularly elevated in lupus mothers of group I. In con- trast, no statistically significant difference was observed between groups I and II of mothers with SS, and low levels of Ro peptide reactive antibodies were measured in asympto- matic mothers who gave birth to babies with NLE. An important feature demonstrated in this study was that, dur- ing the critical window of pregnancy between 18 and 30 weeks of gestation, there was a high level of IgG antibodies reacting with Ro52 peptides 1–13, 277–292 and 365–382 in lupus mothers of group I. Discussion total test antigen used in immunodiffusion or to the fact that the Ro antigen used was extracted from bovine spleen, which is known to be less effectively recognized by patients' autoan- tibodies than human Ro [25,26]. study, synthetic peptides 13–24 residues long were used in an ELISA to analyze the Ro52 and Ro60 antibody response in mothers whose children have NLE. The whole proteins Ro52, Ro60 and La were also included in this study. The 192 sera from a total of 66 mothers in the two different clinical groups I and II (with or without infants with NLE) as well as the 43 dis- ease controls were studied. The appearance of protein and peptide-reactive antibodies was examined before and during the time of pregnancy, as well as after delivery. A second set of data was obtained by examining the reactivity of sera with 45 peptides of Ro52 and Ro60 proteins. Eleven Ro peptides were recognized by IgG antibodies from at least 25% of mothers included in this study. These peptides encom- pass residues 1–13, 50–64, 93–116, 107–122, 107–126, 236–250, 277–292, 365–382 of Ro52 and residues 18–38, 21–41 and 304–324 of Ro60. Although the actual fragments 176–196 and 200–239 of Ro52 described by Wahren-Herle- nius and colleagues [23,24] were not tested in this study, thus precluding any direct conclusion, we noted infrequent reactiv- ity in the four peptides covering these regions (Ro52 peptides 178–193, 191–208, 206–224, 222–235). While the reactiv- A thorough mapping of autoantibody specificities was under- taken. The high frequency of IgG antibodies to the whole pro- teins Ro52, Ro60 and La in all selected sera was notable, but a large number of discrepancies between the results obtained via immunodiffusion, Western blotting and ELISA was observed. This lack of correlation has been described previ- ously and may be due, for example, to the absence of Ro52 in Page 8 of 11 (page number not for citation purposes) Page 8 of 11 (page number not for citation purposes) Available online http://arthritis-research.com/content/8/1/R4 Figure 3 Figure 3 Reactivity in ELISA of sera collected from lupus mothers of groups I and II during pregnancy Reactivity in ELISA of sera collected from lupus mothers of groups I and II during pregnancy. Sera were classified in four subgroups, corresponding to weeks 1–8, 16–20, 26–30 and 31–35 of gestation. The number of sera in each subgroup is indicated (n). Sera were tested at a 1:1,000 dilution. Authors' contributions 13. Sallé L, Eftekhari P, Aupart M, Cosnay P, Hoebeke J, Argibay JA: Inhibitory activity of antibodies against the human atrial 5-HT4 receptor. J Mol Cell Cardiol 2001, 33:405-417. CF performed and analyzed the immunoassays. JH was involved in the analysis of the immunoassay results. HD per- formed and analyzed the immunoassays. VR performed and analyzed the immunoassays. DAI collected the patient sera and provided patient data. OM conceived of the study, participated in its design, collected the patient sera and pro- vided patient data. SM conceived of the study and was involved in its design and coordination. All authors read and approved the final manuscript. 14. Eftekhari P, Roegel JC, Lezoualc'h F, Fischmeister R, Imbs JL, Hoe- beke J: Induction of neonatal lupus in pups of mice immunized with synthetic peptides derived from amino acid sequences of the serotoninergic 5-HT4 receptor. Eur J Immunol 2001, 31:573-579. 15. Buyon JP, Clancy R, Di Donato F, Miranda-Carus ME, Askanase AD, Garcia J, Qu Y, Hu K, Yue Y, Chan EK, Boutjdir M: Cardiac 5- HT4 serotoninergic receptors, 52 kD SSA/Ro and autoim- mune-associated congenital heart block. J Autoimmun 2002, 19:79-86. 16. Ricchiuti V, Briand JP, Meyer O, Isenberg DA, Pruijn G, Muller S: Epitope mapping with synthetic peptides of 52-kD SSA/Ro protein reveals heterogeneous antibody profiles in human autoimmune sera. Clin Exp Immunol 1994, 95:397-407. Conclusion Longitudinal analysis of mothers with SLE and SS showed that in the group of lupus mothers whose at least one child had NLE, a significantly higher frequency of IgG antibodies to Ro52 peptides 107–122 and 277–292 was observed. Between 18 and 30 weeks of gestation, the period of risk, there was clearly an elevated level of circulating antibodies reacting with Ro52 peptides 1–13, 277–292 and 365–382. This result is particularly important since antibodies to Ro52 peptide 365–382 have been shown previously to cross-react with residues 165–185 of the heart 5-HT4 serotoninergic receptor and might be pathologically important. The level of these Ro52 antibody subsets decreased at the end of preg- nancy and after delivery. IgG antibodies to Ro52 peptides 1– 13, 107–122, 277–292 and 365–382 could therefore be important to predict a complication in pregnant lupus women with Ro52 antibodies. 7. Garcia S, Nascimiento JH, Bonfa E, Levy R, Oliveira SF, Tavares AV, de Carvalho AC: Cellular mechanisms of the conduction abnormalities induced by serum from anti-Ro/SSA-positive patients in rabbit hearts. J Clin Invest 1994, 93:718-724. 8. 8. Boutjdir M, Chen L, Zhang ZH, Tseng CE, Di Donato F, Rashbaum W, Morris A, el-Sherif N, Buyon JP: Arrhythmogenicity of IgG and anti-52 kD SSA/Ro affinity purified antibodies from mothers of children with congenital heart block. Circ Res 1997, 80:354-362. 9. Miranda-Carus ME, Boutjdir M, Tseng CE, DiDonato F, Chan EK, Buyon JP: Induction of antibodies reactive with SSA/Ro-SSB/ La and development of congenital heart block in a murine model. J Immunol 1998, 161:5886-5892. 10. Li JM, Horsfall AC, Maini RN: Anti-La (SS-B) but not anti-Ro52 (SS-A) antibodies cross-react with laminin – a role in the pathogenesis of congenital heart block? Clin Exp Immunol 1995, 99:316-324. , 11. Chang SH, Huh MS, Kim HR, Kim IS, Lee JS, Semsei I, Grölz D, Bachmann M: Cross reactivity of antibodies immunoadsorbed to laminin with recombinant human La (SS-B) protein. J Autoimmun 1998, 11:163-167. Acknowledgements The authors thank G Pruijn and W van Venrooij (Nijmegen) for a gift of recombinant Ro52, and thank J-P Briand for the synthesis of peptides. This work was supported by CNRS. p 17. Barakat S, Meyer O, Torterotot F, Youinou P, Briand JP, Kahn MF, Muller S: IgG antibodies from patients with primary Sjögren's syndrome and systemic lupus erythematosus recognize dif- ferent epitope in 60-kD SSA/Ro protein. Clin Exp Immunol 1992, 89:38-45. Competing interests , 12. Eftekhari P, Sallé L, Lezoualc'h F, Mialet J, Gastineau M, Briand JP, Isenberg DA, Fournié GJ, Argibay J, Fischmeister R, et al.: Anti- SSA/Ro52 autoantibodies blocking the cardiac 5-HT4 serot- oninergic receptor could explain neonatal lupus congenital heart block. Eur J Immunol 2000, 30:2782-2790. p g The authors declare that they have no competing interests. Arthritis Research & Therapy Vol 8 No 1 Fritsch et al. 3. Dörner T, Feist E, Pruss A, Chaoui R, Göldner B, Hiepe F: Signif- icance of antibodies in neonatal lupus erythematosus. Int Arch Allergy Immunol 2000, 123:58-66. Our previous studies have provided some important features concerning the pathological consequences for the fetal heart of antibodies to 5-HT4-R [12-14]. It would be of interest to prolong this study by demonstrating the possible physiopatho- logical role of Ro antibodies reacting with Ro52 peptide 365– 382, and to determine whether the other antibody subsets of Ro52 antibodies (antibodies reacting with Ro52 peptides 1– 13, 107–122 and 277–292, for example) also generate elec- trophysiological disturbances compatible with CHB. 4. Brucato A, Frassi M, Franceschini F, Cimaz R, Faden D, Pisoni MP, Muscara M, Vignati G, Stramba-Badiale M, Catelli L, et al.: Risk of congenital complete heart block in newborns of mothers with anti-Ro/SSA antibodies detected by counterimmunoelectro- phoresis: a prospective study of 100 women. Arthritis Rheum 2001, 44:1832-1835. 5. , 5. Horsfall AC, Venables PJ, Taylor PV, Maini RN: Ro and La anti- gens and maternal anti-La idiotype on the surface of myocar- dial fibres in congenital heart block. J Autoimmun 1991, 4:165-176. 6. Reichlin M, Brucato A, Frank MB, Maddison PJ, McCubbin VR, Wolfson-Reichlin M, Lee LA: Concentration of autoantibodies to native 60-kd Ro/SS-A and denatured 52-kd Ro/SS-A in elu- ates from the heart of a child who died with congenital com- plete heart block. Arthritis Rheum 1994, 37:1698-1703. Discussion This result is particularly important to highlight because these antibodies might play an important role in the pathogenesis of CHB at an early stage during fetal cardiac development, and also because the Ro52 sequence 365–382 does correspond to the site of homology with the serotoninergic 5-HT4-R [12-14]. It has been confirmed recently that IgG antibodies reacting with peptide 165–185 of 5-HT4-R effectively occurred in a higher proportion of mothers whose children had CHB [27]. Although a meta-analysis should be performed to confirm the data, this study raises the point that tracing IgG antibodies reacting with peptide 365– 382 of Ro52 might be important in patients with lupus to fol- low at-risk pregnancies. The lack of significant association of any antibody subset in groups I and II of patients with SS is intriguing. It is not known whether this result suggests that there are different physio- pathological mechanisms involved in SLE and SS. This important question will be examined further in a larger group of mothers. On the other hand, since La reactivity within the group of mothers with SLE seems to be significantly more prevalent in group I compared with group II (Table 3), another Page 9 of 11 (page number not for citation purposes) Arthritis Research & Therapy Vol 8 No 1 Fritsch et al. References 1. Clancy RM, Buyon JP: Autoimmune-associated congenital heart block: dissecting the cascade from immunologic insult to relentless fibrosis. Anat Rec A Discov Mol Cell Evol Biol 2004, 280:1027-1035. 1. Clancy RM, Buyon JP: Autoimmune-associated congenital heart block: dissecting the cascade from immunologic insult to relentless fibrosis. Anat Rec A Discov Mol Cell Evol Biol 2004, 280:1027-1035. 18. Ricchiuti V, Pruijn GJM, Thijssen JP, van Venrooij WJ, Muller S: Accessibility of epitopes on the 52-kD Ro/SSA protein (Ro52) and on the RoRNP associated Ro52 protein as determined by anti-peptide antibodies. J Autoimmun 1997, 10:181-191. 2. Buyon JP, Winchester RJ, Slade SG, Arnett F, Copel J, Friedman D, Lockshin MD: Identification of mothers at risk for congenital heart block and other neonatal lupus syndromes in their chil- dren. Comparison of enzyme-linked immunosorbent assay and immunoblot for measurement of anti-SS-A/Ro and anti- SS-B/La antibodies. Arthritis Rheum 1993, 36:1263-1273. 2. Buyon JP, Winchester RJ, Slade SG, Arnett F, Copel J, Friedman D, Lockshin MD: Identification of mothers at risk for congenital heart block and other neonatal lupus syndromes in their chil- dren. Comparison of enzyme-linked immunosorbent assay and immunoblot for measurement of anti-SS-A/Ro and anti- SS-B/La antibodies. Arthritis Rheum 1993, 36:1263-1273. anti peptide antibodies. J Autoimmun 1997, 10:181 191. 19. Ricchiuti V, Isenberg D, Muller S: HLA association of anti-Ro60 and anti-Ro52 antibodies in Sjögren's syndrome. J Autoimmun 1994, 7:611-621. , 20. Scofield RH, Farris AD, Horsfall AC, Harley JB: Fine specificity of the autoimmune response to the Ro/SSA and La/SSB ribonucleoproteins. Arthritis Rheum 1999, 42:199-209. Page 10 of 11 (page number not for citation purposes) Available online http://arthritis-research.com/content/8/1/R4 21. Wahren-Herlenius M, Muller S, Isenberg D: Analysis of B-cell epitopes of the Ro/SSA autoantigens. Immunol Today 1999, 20:234-240. 22. Moutsopoulos NM, Routsias JG, Vlachoyiannopoulos PG, Tzioufas AG, Moutsopoulos HM: B-cell epitopes of intracellular autoan- tigens: myth and reality. Mol Med 2000, 6:141-151. S l S D T Th d E B K L P , p p p tigens: myth and reality. Mol Med 2000, 6:141-151. 23. Salomonsson S, Dörner T, Theander E, Bremme K, Larsson P, Wahren-Herlenius M: A serologic marker for fetal risk of con- genital heart block. Arthritis Rheum 2002, 46:1233-1241. g genital heart block. Arthritis Rheum 2002, 46:1233 S S S S O 24. Page 11 of 11 (page number not for citation purposes) References Salomonsson S, Sonesson SE, Ottosson L, Muhallab S, Olsson T, Sunnerhagen M, Kuchroo VK, Thorén P, Herlenius E, Wahren-Her- lenius M: Ro/SSA autoantibodies directly bind cardiomyocytes, disturb calcium homeostasis, and mediate congenital heart block. J Exp Med 2005, 201:11-17. p 25. Reichlin M, Wolfson Reichlin M: Autoantibodies to the Ro/SS-A particle react preferentially with the human antigen. J Immunol 1989, 2:359-365. 26. Slobbe RL, Pruijn GJ, Damen WG, Van der Kemp JW, Van Venrooij WJ: Detection and occurence of the 60- and 52-kD Ro (SS-A) antigens and of autoantibodies against these proteins. Clin Exp Immunol 1991, 86:99-105. p , 27. Kamel R, Eftekhari P, Clancy R, Buyon JP, Hoebeke J: Autoanti- bodies serotoninergic against the 5-HT4 receptor and congen- ital heart block: a reassessment. J Autoimmun 2005, 25:72-76. Page 11 of 11 (page number not for citation purposes) Page 11 of 11 (page number not for citation purposes)
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Meningitis caused by Salmonella enterica serotype Panama in Brazil: first case reported
Revista da Sociedade Brasileira de Medicina Tropical
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Abstract Salmonella infections usually occur as gastroenteritis that is generally self-limited. However, some serotypes of Salmonella can cause severe extra-intestinal infections, such as bacteremia and meningitis. Here, we report the first Salmonella Panama case of meningitis in 4-month-old male newborn in Brazil. The invasive strain isolated was susceptible to all antimicrobial agents tested. The genes agfA, fimA, invA, sfbA, phoP, and slyA were detected using polymerase chain reactions. These findings are relevant and physicians should be alert to the possibility of meningitis in newborns due to S. Panama, which can present a high rate of mortality or recurrence of infection. Keywords: S. Panama. Meningitis. Newborn. Keywords: S. Panama. Meningitis. Newborn. Keywords: S. Panama. Meningitis. Newborn. INTRODUCTION and the concentration of glucose was 134mg/dL. Gram staining of the CSF was positive for gram-negative bacilli. The patient showed drowsiness with a fixed upward stare, irritation, a lack of appetite to the extent of rejecting food, and uncontrolled movements in the right arm resembling convulsions or shock. The patient was then moved to a larger medical center in the City of Fortaleza, where he was diagnosed with neck rigidity and fontanel protuberant. Salmonella Panama belongs to the D1 serogroup and is frequently found in cases of nontyphoid salmonellosis in patients from different countries1,2. This serotype generally causes gastroenteritis, but it is one of the many serotypes that tends to cause invasive illnesses and may be associated with bacteremia and meningitis in children1-4. We describe here the first case of meningitis in humans caused by S. Panama in Brazil. The CSF sample was subjected to bacteriological analysis and standard biochemical reactions yielded the presence of Salmonella spp., which was subsequently typed as S. enterica serotype Panama. Blood culture testing was not carried out. The isolate was sensitive to ampicillin, ceftazidime, ceftriaxone, ciprofloxacin, chloramphenicol, and sulfamethoxazole-trimethoprim. The patient was initiated on intravenous ceftriaxone for 21 days (80mg/kg of body weight/ day). CSF analysis carried out before his discharge from the hospital revealed a cell count of 40/mm3, of which 89% were lymphocytes and 7% were neutrophils. The protein and glucose concentrations were 132mg/dL and 12mg/dL, respectively. Blood analysis revealed a leucocyte concentration of 8.6×103 cells/mm3, with a neutrophilic versus mononuclear cell ratio of 64% versus 34%. The platelet count was 393,000 cells/mm3. The CSF bacterioscopy and culture, and the urine cultures were negative for S. Panama. Stool culture was not carried out on admission or on discharge. The patient lived with his parents and his 5-year-old brother, who were all healthy, in a good-standard residence in terms of plumbing and sanitary conditions, and the family had a pet dog. Maria Regina Pires Carneiro[1], Maria Iracema de Aguiar Patrício[2], Sona Jain[1], Dalia dos Prazeres Rodrigues[3] and Sergio Eduardo Longo Fracalanzza[4] [1]. Departamento de Morfologia, Universidade Federal de Sergipe, São Cristóvão, SE, Brasil. [2]. Laboratório Central de Saúde Pública, Secretaria de Saúde do Estado do Ceará, Fortaleza, CE, Brasil. [3]. Laboratório de Referência Nacional de Enteroinfecções Bacterianas, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil. [4]. Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brasil. Rev Soc Bras Med Trop 51(2):244-246, March-April, 2018 doi: 10.1590/0037-8682-0367-2017 Case Report Corresponding author: Drª Maria Regina Pires Carneiro. e-mail: profregina@hotmail.com Received 23 September 2017 Accepted 25 January 2018 DISCUSSION incriminated as the source of S. Panama in a case of meningitis in a newborn. On the other hand, rehydration of powdered milk with contaminated water could also carry infection. However, we did not find any reference of the type of food consumed in the patient’s records. The fecal-oral transmission from an adult living in the same house is a possibility1, but this hypothesis was not investigated in cultures of fecal material from the parents or the brother, even if they did not exhibit symptoms, which does not exclude the possibility of an asymptomatic infection or carrier condition. S. Panama has been found to colonize or cause infection in dogs12 and the family of the patient studied considered the presence of a pet dog, but this hypothesis was not analyzed either. An interesting point in our study was the susceptibility of the S. Panama isolate to all the antimicrobials tested. Similar results were obtained in a wider study carried out with 43 S. Panama isolates obtained from the same geographical region (NE Brazil), from different sources such as human, animal, and food (unpublished data). In contrast with our findings, studies carried out in other countries including Brazil have suggested that invasive strains of S. Panama generally present a very high resistance rate to antimicrobial agents3,5-7. Our results suggest that the acquisition of antimicrobial resistance may not be the main factor of virulence that favors the colonization and posterior invasion of S. Panama in humans in Brazil. Thus, we report in this paper the first case of meningitis caused by S. Panama in a 4-month-old baby in Brazil. This finding is relevant and Brazilian physicians should be alert to the possibility of the occurrence of meningitis in newborns under 12 months of age that have Salmonella detected in feces, urine, and blood, especially S. Panama, which can be invasive and present a high rate of mortality or recurrence of infection. Virulence markers produced by the invasive strain were analyzed using polymerase chain reaction (PCR) assays, which revealed the presence agfA and fimA (related to adherence to host cell receptors), invA (invasion), sfbA (component of the iron transport system), phoP (survival in macrophages), and slyA (resistance to oxidative stress) genes. Acknowledgements The authors thank Central Laboratory of Public Health [Laboratório Central de Saúde Pública (LACEN)] of the Ceará, Pernambuco, Bahia, Sergipe and Rio Grande do Norte States for providing Salmonella strains. DISCUSSION The presence and expression of these virulence genes could play an important role and contribute to the capacity of this serotype to cause illnesses, including invasive illnesses such as meningitis, as has already been shown with other serotypes of Salmonella species8. Experiments carried out using the murine infection model showed that some serotypes of Salmonella could have invasive characteristics, but S. Panama did not show this ability9. However, another study suggested that S. Panama is more invasive than S. Typhimurium when tested in Hep-2 cells2. CASE REPORT A 4-month-old male newborn weighing 5,500g with a body temperature of 39ºC, diarrhea, and cough was taken to a small hospital in the town of Russas, 150km from Fortaleza, the capital of Ceará State, Northeast (NE) Brazil, where he was admitted and remained for two days with suspected virosis. Without showing any improvement, the patient underwent lumbar puncture and the cerebrospinal fluid (CSF) presented intense pleocytosis with a leucocytic count of 11.9×103 cells/mm3 (neutrophilic versus mononuclear cells, 93% versus 7%). The erythrocyte count in the CSF was 320 cells/mm3, concentration of proteins was 440mg/dL, and glucose level was 1 mg/dL. The blood analysis revealed a leucocytic count of 11.1 x 103 cells/ mm3 (neutrophilic versus mononuclear cells, 86% versus 14%) Corresponding author: Drª Maria Regina Pires Carneiro. e-mail: profregina@hotmail.com Received 23 September 2017 Accepted 25 January 2018 244 Carneiro MRP et al. - Meningitis caused by S. panama Conflict of interest The authors declare that there is no conflict of interest. The authors declare that there is no conflict of interest. Few articles in the international scientific literature show the presence of virulence-related genes in S. Panama isolates8-11. In strains of animals originating from Spain, it was demonstrated that S. Panama harbored all the virulence genes tested, such as invE/A, phoP/Q, stn, iroB, slyA, hin/H2, and agfA10. Another study also carried out in Spain in the Principality of Asturias with isolates from different sources showed that all the strains of S. Panama were negative for spvC, which is a virulence plasmidial gene, but were positive for invA, phoP, stn, and slyA8. More studies are necessary to clarify the role of virulence-related genes in the invasiveness of the S. Panama serotype. 12. Tsai HJ, Huang HC, Lin CM, Lien YY, Chou CH. Salmonellae and campylobacters in household and stray dogs in northern Taiwan. Vet Res Commun. 2007;31(8):931-9. 8. Soto SM, Guerra B, del Cerro A, González-Hevia MA, Mendoz MC. Outbreaks and sporadic cases of Salmonella serovar panama studied by DNA fingerprinting and antimicrobial resistance. Int J Food Microbiol. 2001;71(1):35-43. REFERENCES 1. Choudhury SA, Berthaud V, Weitkamp JH. Meningitis caused by Salmonella Panama in infants. J Natl Med Assoc. 2006;98(2):219-22. 2. Yang YJ, Huang MC, Wang SM, Wu JJ, Cheng CP, Liu CC. Analysis of risk factors for bacteremia in children with nontyphoidal Salmonella gastroenteritis. Eur J Clin Microbiol Infect Dis. 2002;21(4):290-3. 3. Tsai KS, Yang YJ, Wang SM, Chiou CS, Liu CC. Change of serotype pattern of Group D non-typhoidal Salmonella isolated from pediatric patients in southern Taiwan. J Microbiol Immunol Infect. 2007;40(3):234-9. Unfortunately, we were not able to determine the source and the route of transmission of the invasive S. Panama strain in the patient. In children with gastroenteritis from nontyphoid Salmonella, prolonged fever over five or more days and infection by a specific serotype of Salmonella, such as S. Panama, are strong factors associated with the development of bacteremia2, and consequently, meningitis. The newborn studied in this work presented a fever of 39ºC for more than five days and had diarrhea, which suggested gastroenteritis, but a stool culture was not requested by the physician that was taking care of the patient. 4. Chen TL, Thien PF, Liaw SC, Fung CP, Siu LK. First report of Salmonella enterica serotype Panama meningitis associated with consumption of contaminated breast milk by a neonate. J Clin Microbiol. 2005;43(10):5400-2. 5. Carvalho FCT, Sousa OV, Carvalho EMR, Hofer E, Vieira RHSF. Antibiotic resistance of Salmonella spp. isolated from shrimp farming freshwater environment in Northeast region of Brazil. J Pathog. 2013;2013, ID 685193:5p. doi:10.1155/2013/685193. 6. Palmeira ALB, Santos LR, Borsoi A, Rodrigues LB, Calasans M, Nascimento VP. Serovars and antimicrobial resistance of Salmonella spp. isolated from turkey and broiler carcasses in southern Brazil between 2004 and 2006. Rev Inst Med Trop São Paulo. 2016;58:19. It is widely known that salmonellosis in humans occurs mainly due to the consumption of contaminated water and food. Due to the age of the patient (4 months), it is probable that he only fed on maternal milk or another type of milk, whether it was natural, pasteurized, or even reconstituted powdered milk. In this situation, contamination could have originated from different sources. In this study, contaminated maternal milk was 7. Huang SC, Chiu CH, Chiou CS, Yang YJ. Multidrug-resistant Salmonella enterica serovar Panama carrying class 1 integrons is invasive in Taiwanese children. J Formos Med Assoc. 2013;112(5):269-75. Salmonella isolated from samples of animal origin. Food Microbiol. 2003;20(4):431-8. Salmonella isolated from samples of animal origin. Food Microbiol. 2003;20(4):431-8. REFERENCES 245 Rev Soc Bras Med Trop 51(2):244-246, March-April, 2018 Salmonella isolated from samples of animal origin. Food Microbiol. 2003;20(4):431-8. 8. Soto SM, Guerra B, del Cerro A, González-Hevia MA, Mendoz MC. Outbreaks and sporadic cases of Salmonella serovar panama studied by DNA fingerprinting and antimicrobial resistance. Int J Food Microbiol. 2001;71(1):35-43. 11. Rowlands REG, Ristori CA, Ikuno AA, Barbosa ML, Jakabi M, Franco BDGM. Prevalence of drug resistance and virulence features in Salmonella spp. isolated from foods associated or not with salmonellosis in Brazil. Rev Inst Med Trop Sao Paulo. 2014;56(6):461-7. 11. 9. Helmuth R, Stephan R, Bunge C, Hoog B, Steinbeck A, Bulling E. Epidemiology of virulence-associated plasmids and outer membrane protein patterns within seven common Salmonella serotypes. Infect Immun. 1985;48(1):175-82. 12. Tsai HJ, Huang HC, Lin CM, Lien YY, Chou CH. Salmonellae and campylobacters in household and stray dogs in northern Taiwan. Vet Res Commun. 2007;31(8):931-9. 10. Del Cerro A, Soto SM, Mendoza MC. Virulence and antimicrobial- resistance gene profiles determined by PCR-based procedures for 246
https://openalex.org/W2122372545
https://biblio.ugent.be/publication/1095705/file/1101030
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74-week follow-up of safety of infliximab in patients with refractory rheumatoid arthritis
Arthritis research & therapy
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10,069
RESEARCH ARTICLE Open Access © 2010 Delabaye and De Keyser; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and repro- duction in any medium, provided the original work is properly cited. Abstract Introduction: The objective was to describe the prevalence, types, and predictors of adverse events (AEs) in rheumatoid arthritis (RA) patients treated with infliximab and methotrexate in a daily clinical setting. Methods: This was a prospective, multi-center, open-label, 74-week observational study in patients with active RA despite treatment with methotrexate and at least one other disease-modifying anti-rheumatic drug. Patients were treated with 3 mg/kg infliximab at weeks 0, 2, and 6 and then every 8 weeks. At weeks 0, 6, 26, 50, and 74, patients answered a health assessment questionnaire, a swollen joint count was made, and adverse events (AEs) occurring during the previous period were registered. Results: Five hundred and seventy-five patients were treated with infliximab, of which 346 were still on infliximab at the study end, 158 discontinued treatment, and 71 were lost to follow-up. Reasons for discontinuation included safety (n = 74), elective reasons (n = 43), and inefficacy (n = 41). Infusion reactions (n = 33) and infections (n = 20) were the most common AEs causing discontinuation and the most common AEs overall. There were four cases of tuberculosis, all of which occurred in patients negative at screening. Total AEs, serious AEs, and infusion reactions as well as discontinuations for AEs were most frequent during the first 26 weeks. Higher age was a predictor of serious adverse events (SAEs), infection, and discontinuation due to an SAE, but odds ratios were close to one. Conclusions: AEs and discontinuations due to AEs occur most frequently during the first half year of infliximab treatment in refractory RA patients. The main reasons for discontinuing treatment are infections and infusion reactions. Tuberculosis and other infections remain an important concern in these patients. advance in the treatment of RA [1]. Many of these biolog- ical agents act by neutralizing TNF-α, which plays a cen- tral role in the chronic inflammation and tissue damage of RA [6]. Infliximab is a monoclonal antibody that binds with high affinity and specificity to human TNF and neu- tralizes its biologic activity [7]. To date, four double- blind, placebo-controlled, randomized studies have been completed in patients with active RA despite DMARD therapy [8-11]. These studies have shown clinical response rates of 40% to 60% in patients treated with a combination of MTX and infliximab. * Correspondence: filip.dekeyser@ugent.be 2 Ghent University, Department of Rheumatology, Ghent University Hospital, De Pintelaan 185, Ghent, B-9000, Belgium Full list of author information is available at the end of the article Delabaye et al. Arthritis Research & Therapy 2010, 12:R121 http://arthritis-research.com/content/12/3/R121 Delabaye et al. Arthritis Research & Therapy 2010, 12:R121 http://arthritis-research.com/content/12/3/R121 Research article 74-week follow-up of safety of infliximab in patients with refractory rheumatoid arthritis Isabelle Delabaye1,3, Filip De Keyser*2 for the REMITRACT study group Isabelle Delabaye1,3, Filip De Keyser*2 for the REMITRACT study group Introduction Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disorder of unknown etiology that occurs in approximately 0.8% of the population [1]. Initial therapy for RA has included non-steroidal anti-inflammatory drugs (NSAIDs), ultimately giving way to oral steroids and disease-modifying antirheumatic drugs (DMARDs). More recent practice is to initiate DMARDs early [2-4]. Methotrexate (MTX) has become the DMARD of choice because of its relatively rapid mode of action and good control during prolonged use; however, for many patients, MTX provides only partial relief of signs and symptoms [5]. The most common adverse events (AEs) found in clini- cal trials of infliximab include upper respiratory tract infection, headache, nausea, sinusitis, rash, pharyngitis, and cough, with infusion reactions (IRs) reported in 5% to 20% of patients [9,12]. Although the clinical trials did not show a significant increase in the risk of infections with the use of infliximab, a meta-analysis of randomized clinical studies found a significantly higher rate of serious The development of biological agents targeting the interaction between effector cells has been a major Delabaye et al. Arthritis Research & Therapy 2010, 12:R121 http://arthritis-research.com/content/12/3/R121 Page 2 of 12 infections [13]. Also, some reports have suggested an increased risk of malignancies, especially lymphoma, in RA patients treated with anti-TNF-α therapies [13-15], but this has been refuted by several recent studies [16- 18]. Several observational and retrospective studies have shown that, in daily practice, up to one-fourth or one- third of patients discontinue infliximab within one year and that roughly one-third of discontinuations are due to AEs, with IRs the most common type causing discontinu- ation [19-21]. teins; serious infections, such as hepatitis, pneumonia, and pyelonephritis in the previous three months; history of opportunistic infections such as herpes zoster within two months of screening; evidence of active cytomegalo- virus, active Pneumocystis carinii, drug-resistant atypical mycobacterium, or other opportunistic infections; docu- mented infection with HIV; current signs or symptoms of severe, progressive, or uncontrolled renal, hepatic, hema- tologic, endocrine, pulmonary, cardiac, neurologic, or cerebral disease; previous or concurrent malignancies, with the exception of surgically cured carcinoma in situ of the cervix and surgically cured basal or squamous cell carcinoma of the skin; alcoholism, alcoholic liver disease, or other chronic liver disease; and congestive heart failure grade III and IV. Here, we performed a multi-center, prospective, obser- vational study on the safety of infliximab in combination with MTX. Treatments Treatment was initiated in eligible patients within four weeks of the screening visit. Patients received an infusion of 3 mg/kg infliximab (Remicade®; Centocor, Leiden, The Netherlands) at weeks 0, 2, and 6 and then every 8 weeks. Dose escalations or shortening of treatment intervals were not permitted. Introduction The aims of this study were to describe the prevalence and types of AEs and identify predictors of AEs and treatment discontinuation. This information should provide expanded data to health care workers and authorities to help estimate and support the appropriate use of infliximab. Study design and patient selection This was a prospective, multi-center, open-label, observa- tional study of infliximab in the treatment of patients with active RA despite treatment with MTX and at least one other DMARD. The study was carried out at 77 cen- ters in Belgium between July 2002 and June 2006. The protocol was approved by the ethics committees of the participating study centers, and the study was conducted in accordance with the Declaration of Helsinki. Prior to initiating treatment, written informed consent was obtained from all patients by the treating physician using a form approved by the ethics committees. The study was not registered because it was purely observational and was started in 2002. Clinical evaluations At screening, demographic data and medical history were obtained, and the patient underwent a physical examina- tion, had routine baseline (hematology and chemistry) exams, a chest X-ray, and a Mantoux test. At screening and at weeks 6, 26, 50, and 74 after the start of treatment, patients completed a HAQ [22]. In addition, a swollen joint count (SJC) based on 66 joints was determined [23]. Concurrent medications were recorded at weeks 6, 26, 50, and 74. Patients eligible for this study had to be diagnosed with erosive RA and have evidence of active disease despite treatment with MTX and at least one other DMARD. Eli- gible patients also had to be on a stable dose of 15 mg/wk or more of MTX given orally or parenterally for at least three months. Patients with intolerance to MTX despite the association with folic acid could also be included. Additional inclusion criteria were as follows: men or women 17 years or older; 8 or more swollen joints; Health Assessment Questionnaire (HAQ) index of 25 or more (HAQ score × 10 ÷ 6); and absence of tuberculosis dem- onstrated by simultaneous negative Mantoux test and negative chest X-ray. In the case of a positive Mantoux test or X-ray, the patient had to have had adequate treat- ment of the tuberculosis for six months before treatment with infliximab. Women of childbearing potential had to be using adequate birth control measures. Statistical analysis 77). Other common (>5%) AEs included dermatological reactions (n = 40), cardiovascular disorders (n = 22), RA- related disease manifestations (n = 17), and gastrointesti- nal disorders (n = 17). The most common SAE was infec- tion (n = 47), followed by IRs (n = 15), cardiovascular events (n = 15), and RA-related disease manifestations (n = 11). 77). Other common (>5%) AEs included dermatological reactions (n = 40), cardiovascular disorders (n = 22), RA- related disease manifestations (n = 17), and gastrointesti- nal disorders (n = 17). The most common SAE was infec- tion (n = 47), followed by IRs (n = 15), cardiovascular events (n = 15), and RA-related disease manifestations (n = 11). Descriptive statistics were used for groups with and with- out AEs, SAEs, and IRs. T-tests were used to examine dif- ferences in the age, age at diagnosis, severity (HAQ index and SJC), the dose of MTX, and the duration of disease between the patients with AEs or SAEs and the patients who had no AEs or SAEs. Fisher's Exact Tests (or chi square tests) were used to look for association between the presence of an AE/SAE and the use of corticosteroids, the use of MTX, and sex. Logistic (stepwise) regression analysis was used to assess the ability of baseline charac- teristics to predict the manifestation of AEs, SAEs, or infections. Fisher's exact test was used to examine the association between the use of corticosteroids and the manifestation of an infection. Means are presented ± standard deviations, and odds ratios are given with 95% confidence intervals (CI). There were 93 reported infections in 81 patients. Infec- tions were most common during the first 26 weeks of the study (Figure 2b). Approximately half (n = 47) of the infections were reported as SAEs (Table 2). For cases where the infectious agent was known, the most common type was non-tuberculosis-type bacteria (n = 38). Tuber- culosis accounted for four of the infections (three con- firmed, one suspected), all of which were considered SAEs. One was a confirmed case of unspecified tubercu- losis in a 28-year-old woman who had been exposed to a family member with an overt tuberculosis infection. The remaining two confirmed cases were pulmonary tubercu- losis in a 38-year-old woman and a 43-year-old man who did not have known exposure to overt tuberculosis. Baseline demographics and patient disposition A total of 596 patients were screened for this study. Of the 596 screened patients, 575 started infliximab. There were 71 losses to follow-up, so that 504 patients were evaluable (Figure 1a). Of these, 158 discontinued inflix- imab before week 74, and the remaining 346 patients were still on infliximab according to protocol at week 74. The baseline demographics of the patients receiving at least one dose of infliximab are shown in Table 1. Nearly three-quarters of the patients (n = 419; 72.9%) were female. The mean age of patients was 57 ± 13 years, and the mean duration of disease was 10.3 ± 9.4 years. The mean HAQ index at screening was 56.1 ± 15.4, and the mean SJC at screening was 16.3 ± 7.5. Almost all patients (n = 537; 93.4%) were taking MTX, and the mean MTX dose was 14.5 mg/week. A total of 596 patients were screened for this study. Of the 596 screened patients, 575 started infliximab. There were 71 losses to follow-up, so that 504 patients were evaluable (Figure 1a). Of these, 158 discontinued inflix- imab before week 74, and the remaining 346 patients were still on infliximab according to protocol at week 74. The baseline demographics of the patients receiving at least one dose of infliximab are shown in Table 1. Nearly three-quarters of the patients (n = 419; 72.9%) were female. The mean age of patients was 57 ± 13 years, and the mean duration of disease was 10.3 ± 9.4 years. The mean HAQ index at screening was 56.1 ± 15.4, and the mean SJC at screening was 16.3 ± 7.5. Almost all patients (n = 537; 93.4%) were taking MTX, and the mean MTX dose was 14.5 mg/week. The 77 reported IRs occurred in 64 patients. Fifteen of these IRs were recorded as SAEs, and 33 led to treatment discontinuation. Overall, the highest incidence of IRs and the highest incidence of IRs leading to discontinuation occurred during the first 26 weeks (Figure 2c). The most common specific symptoms associated with IRs were allergic skin reactions (n = 24) and hemodynamic events (n = 16; Table 3). Both allergic skin reactions and hemo- dynamic events were most frequent during the first 26 weeks (i.e., following infusion at weeks 6, 14, and 22). Safety evaluations Safety data were collected at weeks 6, 26, 50, and 74 for events occurring during weeks 0 to 6, 7 to 26, 27 to 50, and 51 to 74, respectively. A serious adverse event (SAE) was defined as any AE that resulted in death, was life- threatening, resulted in a persistent or significant disabil- ity or incapacity, required hospitalization or prolonged a hospitalization, or resulted in a congenital anomaly or birth defect. Also, important medical events that may not have resulted in death, were not life-threatening, or did not require hospitalization may have been considered a SAE when, according to the investigator, they jeopardized the subject or required medical or surgical intervention to prevent one of the outcomes defining a SAE. An IR was defined as any AE that occurred during an infusion, within one hour after an infusion, or was considered by the investigator to be infusion-related. For each time period, the presence or absence of IRs was recorded only once. Exclusion criteria were as follows: women pregnant, nursing, or planning a pregnancy within two years of enrollment; a history of known allergies to murine pro- Delabaye et al. Arthritis Research & Therapy 2010, 12:R121 http://arthritis-research.com/content/12/3/R121 Delabaye et al. Arthritis Research & Therapy 2010, 12:R121 http://arthritis-research.com/content/12/3/R121 Page 3 of 12 Efficacy of therapy Efficacy of the treatment was assessed using the HAQ and by counting the number of swollen joints. The mean HAQ index decreased from 56.0 ± 15.4 at baseline to 29.0 ± 21.4 at week 74 (P < 0.0001), and the SJC decreased from 16.3 ± 7.5 at baseline to 3.2 ± 4.0 at week 74 (P < 0.0001). During the study, seven tumors were reported in seven patients (Table 2). Four of the tumors were malignant (one epidermoid epithelioma of the right lung, one lung cancer, one carcinoma in situ of the cervix, and one case of chronic myelomonocytic leukemia). Tumors led to dis- continuation of treatment in five cases. Further details about these cases are presented in the Supporting infor- mation in Additional file 1. Baseline demographics and patient disposition Other common IRs (>5%) included hyperventilation/dys- pnea (n = 13), flushing (n = 7), hypertension (n = 6), tachycardia/palpitation (n = 5), and headache (n = 4), all of which were most frequent during the first 26 weeks of treatment. Statistical analysis The fourth case was suspected tuberculosis meningitis in a 69-year-old man that was not confirmed by laboratory tests and later had a differential diagnosis of viral menin- gitis. All four reported cases of tuberculosis were in patients taking corticosteroids at baseline. Further details about the cases of tuberculosis are presented in the Sup- porting information in Additional file 1. Adverse events Patients screened (n=596) Did not start infliximab (n=21) Patients started on infliximab (n=575) Treatment discontinuations (n=158) Safety (n=74) Non-serious AE (n=27) SAE (n=47) Inefficacy (n=41) Elective (n=43) Noncompliance with protocol (n=22) Patient withdrew consent (n=17) Other (n=4) Patients still on infliximab at study end (week 74) (n=346) Lost to follow-up (n=71) (a) (b) Evaluable patients (n=504) Discontinuation- safety (n=74) 14.7% Discontinuation- inefficacy (n=41) 8.1% Discontinuation- elective (n=43) 8.5% Completed to w eek 74 (n=346) 68.7% (c) 575 524 444 369 346 0 100 200 300 400 500 600 700 Week 0 Week 6 Week 26 Week 50 Week 74 Patients on infliximab Patients screened (n=596) Did not start infliximab (n=21) Patients started on infliximab (n=575) Treatment discontinuations (n=158) Safety (n=74) Non-serious AE (n=27) SAE (n=47) Inefficacy (n=41) Elective (n=43) Noncompliance with protocol (n=22) Patient withdrew consent (n=17) Other (n=4) Patients still on infliximab at study end (week 74) (n=346) Lost to follow-up (n=71) (a) Evaluable patients (n=504) Patients screened (n=596) Did not start infliximab (n=21) Patients started on infliximab (n=575) Treatment discontinuations (n=158) Safety (n=74) Non-serious AE (n=27) SAE (n=47) Inefficacy (n=41) Elective (n=43) Noncompliance with protocol (n=22) Patient withdrew consent (n=17) Other (n=4) Patients still on infliximab at study end (week 74) (n=346) Lost to follow-up (n=71) (a) Evaluable patients (n=504) (a) Patients screened (n=596) Did not start infliximab (n=21) Lost to follow-up (n=71) Evaluable patients (n=504) Treatment discontinuations (n=158) Safety (n=74) Non-serious AE (n=27) SAE (n=47) Inefficacy (n=41) Elective (n=43) Noncompliance with protocol (n=22) Patient withdrew consent (n=17) Other (n=4) (b) Discontinuation- safety (n=74) 14.7% Discontinuation- inefficacy (n=41) 8.1% Discontinuation- elective (n=43) 8.5% Completed to w eek 74 (n=346) 68.7% (c) 575 524 444 369 346 0 100 200 300 400 500 600 700 Week 0 Week 6 Week 26 Week 50 Week 74 Patients on infliximab (c) (b) Discontinuation- safety (n=74) 14.7% Figure 1 Patient disposition. (a) Flow chart of patient disposition. A total of 596 patients were screened for this study, of which 575 started infliximab. Of these, 71 were lost to follow-up, so that 504 were evaluated. There were 158 patients that discontinued treatment before week 74, and the remain- ing 346 completed the study according to protocol and were still on infliximab at study end. 'Other' under treatment discontinuations included three patients that wished to become pregnant and one that withdrew prior to an elective surgery. (b) Patients remaining on infliximab at each visit. Adverse events A total of 338 AEs were registered during the study. Of these, 121 (35.8%) were considered SAEs (Table 2). The highest number of AEs occurred during the first 26 weeks of treatment with infliximab (Figure 2a). Thereafter, the incidence of AEs decreased gradually over time. Similarly, AEs considered serious (SAEs) were most common dur- ing the first 26 weeks. There were 22 cardiovascular disorders reported dur- ing the study, 15 of which (68.2%) were considered SAEs. Four of these events led to discontinuation, including one As detailed in Table 2, infection was the most com- monly reported type of AE (n = 93), followed by IRs (n = Delabaye et al. Arthritis Research & Therapy 2010, 12:R121 http://arthritis-research.com/content/12/3/R121 Page 4 of 12 Figure 1 Patient disposition. (a) Flow chart of patient disposition. A total of 596 patients were screened for this study, of which 575 started infliximab. Of these, 71 were lost to follow-up, so that 504 were evaluated. There were 158 patients that discontinued treatment before week 74, and the remain- ing 346 completed the study according to protocol and were still on infliximab at study end. 'Other' under treatment discontinuations included three patients that wished to become pregnant and one that withdrew prior to an elective surgery. (b) Patients remaining on infliximab at each visit. (c) Fraction of evaluable patients completing the study or discontinuing for safety reasons, inefficacy, or elective reasons. Treatment discontinuations The number of patients remaining in the study at each visit is shown in Figure 1b. Of the 504 evaluable patients, a total of 158 (31.3%) discontinued treatment before week 74, so that the continuation rate at the end of the study was 68.7% (Figure 1c). The leading reason for discontinu- ation was safety (n = 74; 14.7% of evaluable patients). Dis- continuation due to inefficacy occurred in 41 cases (8.1%; Figure 1c). The remaining discontinuations (n = 43; 8.5%) were due to elective reasons, including withdrawal of consent (n = 17), noncompliance with the study protocol (n = 22), wish for pregnancy (n = 3), and wish to stop prior to an elective surgery (n = 1). Of the 74 discontinua- tions for safety, the majority (n = 47) were for SAEs, although many (n = 27) were for AEs that were not seri- ous (Figure 1a). Treatment discontinuations overall and for safety or inefficacy were most common during the first 26 weeks (Figure 3). The AEs most commonly leading to discontinuation were IRs (n = 33), infections (n = 20), tumors (n = 5 (2 benign and 3 malignant)), cardiovascular events (n = 4), and dermatological disorders (n = 4; Table 2). There was a significant association between the occurrence of an AE and discontinuation due to the AE for IRs (P < 0.0001), tuberculosis (P = 0.034), tumors (P = 0.0065), and malig- nant tumors (P = 0.034). Non-serious AEs leading to dis- continuation included IRs (n = 21), dermatological disorders (n = 3), neurological (optical neuritis) disorders (n = 1), psychiatric disorders (n = 1), and RA-related symptoms (n = 1). Adverse events (c) Fraction of evaluable patients completing the study or discontinuing for safety reasons, inefficacy, or elective reasons. Page 5 of 12 Delabaye et al. Arthritis Research & Therapy 2010, 12:R121 http://arthritis-research.com/content/12/3/R121 Table 1: Baseline demographics of patients receiving at least one dose of infliximab Characteristic Value Age (years) (n = 575) Mean ± SD 57 ± 13 Median 58 Range 19 -99 Sex Female, N (%) 419 (72.9%) Male, N (%) 156 (27.1%) Age at diagnosis (years) (n = 564) Mean ± SD 46.2 ± 13.6 Median 47 Range 5-81 Duration of disease (years) (n = 564) Mean ± SD 10.3 ± 9.4 Median 8 Range 0-53 HAQ index at screening (n = 573) Mean ± SD 56.1 ± 15.4 Median 55 Range 2-98 Swollen joint count at screening (n = 568) Mean ± SD 16.3 ± 7.5 Median 14 Range 0-49 MTX doses in mg/week (n = 425) Mean ± SD 14.5 ± 3.0 Median 15 Range 5-25 MTX use Yes, N (%) 537 (93.4%) No, N (%) 14 (2.4%) Unknown, N (%) 24 (4.2%) NSAID use Yes, N (%) 414 (72%) No, N (%) 46 (8%) Unknown, N (%) 115 (20%) Corticosteroid use Yes, N (%) 341 (59.3%) No, N (%) 84 (14.6%) Unknown, N (%) 150 (26.1%) HAQ, health assessment questionnaire; MTX, methotrexate; NSAIDs, nonsteroidal anti-inflammatory drugs; SD, standard Table 1: Baseline demographics of patients receiving at least one dose of infliximab pulmonary thromboembolism, one case of cardiac isch- emia, and two fatal events (one myocardial infarct and one cardiac arrest). Of the dermatological and gastroin- testinal disorders reported, most (38/40 (95%) and 16/17 (94.1%), respectively) were not considered SAEs. There were a total of nine deaths during the study, including five for which the main cause of death was infection (three bacterial, one other opportunistic infec- tion, and one unknown type), two due to cardiovascular events (one cardiac arrest and one myocardial infarct), one due to a traumatic event (traffic accident), and one due to a psychiatric disorder (suicide). All patients that died for health reasons were at least 69 years old at the time of death. Details about the deaths occurring during this study are provided in the Supporting information in Additional file 1. Predictors of adverse events, infusion reactions, and treatment discontinuation Statistical tests were used to determine whether baseline demographics (age at screening, age at diagnosis, dura- tion of disease, HAQ index, SJC, sex, use of corticoster- oids, and dose of MTX) were associated with or could Delabaye et al. Arthritis Research & Therapy 2010, 12:R121 http://arthritis-research.com/content/12/3/R121 Page 6 of 12 Table 2: Types and severity of adverse events All AEs SAEs AEs Leading to discontinuation Any 338 (168) 121 (89) 74 Infection 93 (81) 47 (42) 20 Tuberculosisa 4 (4) 4 (4) 3 Other bacterial Infection 38 (33) 29 (24) 10 Viral Infection 8 (8) 5 (5) 1 Opportunistic infectiona 8 (8) 3 (3) 2 Other 35 (32) 6 (6) 4 Infusion reactionb 77 (64) 15 (15) 33 Dermatological disorders 40 (33) 2 (2) 4 Cardiovascular disorders 22 (20) 15 (13) 4 RA-related disease manifestations 17 (16) 11 (11) 2 Gastrointestinal disorders 17 (16) 1 (1) - Respiratory disorders 11 (10) 4 (4) - Neurologic disorder 11 (10) 1 (1) 1 Non-RA joint manifestations 8 (8) 4 (4) - Tumora 7 (7) 6 (6) 5 Benign 3 (3) 2 (2) 2 Malignant 4 (4) 4 (4) 3 Traumatic event 7 (7) 4 (4) 1 Hematologic disorders 4 (4) 4 (4) 1 Psychiatric disorders 3 (3) 1 (1) 2 Liver toxicities 2 (2) 1 (1) - Other 19 (16) 5 (5) 1 Values are numbers of AEs, with the number of patients affected shown in parentheses. a See Supporting information in Additional file 1 for further details. b Individual infusion reactions are described in Table 3. AE, adverse event; RA, rheumatoid arthritis; SAE, serious adverse event. Table 2: Types and severity of adverse events was longer than most randomized clinical trials that have examined the safety of infliximab (mean 0.8 years) [16]. In this study, the most common reason for discontinuing treatment was an AE, of which infections and IRs were the most frequent causes. We also found that AEs as well as discontinuations for AEs most often occurred during the first 26 weeks of treatment. predict the manifestation of AEs overall, infections, or IRs or the discontinuation of treatment. Higher age at screening was significantly associated with (P = 0.043) AEs. Predictors of adverse events, infusion reactions, and treatment discontinuation In addition, higher age was a predictor of the mani- festation of AEs (P = 0.0016), infection (P = 0.018), and discontinuation due to an SAE (P = 0.0017), but the odds ratios were all close to 1.0 (1.047 (95% CI, 1.018 to 1.077)), 1.047 (95% CI, 1.008 to 1.087), and 1.076 (95% CI, 1.028 to 1.127), respectively). Neither corticosteroid use nor any of the other baseline variables besides age was associated with or was predictive (P > 0.05) of the occur- rence of AEs overall, SAEs, infections, IRs, or discontinu- ation for AEs, SAEs, IRs, or inefficacy. Our study confirmed that infections are the most com- mon type of AE in RA patients receiving the combination of infliximab and MTX [20,24,25]. Approximately half of all infections were considered SAEs, and infections were also the most common type of SAE. The rate of infections considered SAEs in this study (7.4%; (42 of 575 patients)) was similar to that reported using the same dose of inflix- imab in ATTEST (Abatacept or infliximab vs placebo, a Trial for Tolerability, Efficacy and Safety in Treating rheu- matoid arthritis) (8.5%) [26]. In addition, after IRs, infec- tions were the second leading cause of discontinuation. Discussion This was a 74-week prospective study on the safety of inf- liximab in patients that had active RA despite treatment with MTX and at least one other DMARD. This study Delabaye et al. Arthritis Research & Therapy 2010, 12:R121 http://arthritis-research.com/content/12/3/R121 Page 7 of 12 (a) 124 49 36 71 33 15 0 50 100 150 200 250 Week 0-26 Week 27-50 Week 51-74 Number of AEs SAE Non-serious AE (a) Figure 2 Incidence of (a) AEs, (b) infections, and (c) IRs during the study. The incidence of (a) all adverse events (AEs), (b) infections, and (c) in- fusion reactions (IRs) are shown for weeks 0 to 26, 27 to 50, and 51 to 74. The week 0 to 26 values were calculated by summing the number events for weeks 0 to 6 and weeks 7 to 26. For each time period, the presence or absence of IRs was recorded only a single time. However, this did not affect the calculation of the week 0 to 26 value from the week 0 to 6 and week 7 to 26 values. (a) (b) 39 12 11 12 3 0 10 20 30 40 50 60 Week 0-26 Week 27-50 Week 51-74 Number of IRs SAE Non-serious AE 124 49 36 71 33 15 0 50 100 150 200 250 Week 0-26 Week 27-50 Week 51-74 Number of AEs SAE Non-serious AE (c) 23 12 11 28 13 6 0 10 20 30 40 50 60 Week 0-26 Week 27-50 Week 51-74 Number of Infections SAEs Non-serious AEs (b) 23 12 11 28 13 6 0 10 20 30 40 50 60 Week 0-26 Week 27-50 Week 51-74 Number of Infections SAEs Non-serious AEs (b) 39 12 11 12 3 0 10 20 30 40 50 60 Week 0-26 Week 27-50 Week 51-74 Number of IRs SAE Non-serious AE (c) (c) Figure 2 Incidence of (a) AEs, (b) infections, and (c) IRs during the study. The incidence of (a) all adverse events (AEs), (b) infections, and (c) in- fusion reactions (IRs) are shown for weeks 0 to 26, 27 to 50, and 51 to 74. The week 0 to 26 values were calculated by summing the number events for weeks 0 to 6 and weeks 7 to 26. For each time period, the presence or absence of IRs was recorded only a single time. Discussion However, this did not affect the calculation of the week 0 to 26 value from the week 0 to 6 and week 7 to 26 values. Delabaye et al. Arthritis Research & Therapy 2010, 12:R121 http://arthritis-research.com/content/12/3/R121 Page 8 of 12 Table 3: Infusion-related events and symptoms Table 3: Infusion-related events and symptoms Week 0 to 6 Week 7 to 26 Week 27 to 50 Week 51 to 74 Total Infusion-related eventsa 23 28 15 11 77 Symptom Allergic skin reaction 2 13 6 3 24 Hemodynamic events (hypotension, syncope, bradycardia, cyanosis) 4 8 2 2 16 Hyperventilation/dyspnea 1 5 5 2 13 Flushing 0 4 2 1 7 Hypertension 2 3 0 1 6 Tachycardia/palpitation 2 2 1 0 5 Headache 1 1 1 1 4 Throat, Quincke's, or mouth edema 0 2 1 0 3 Polyathralgia 2 0 0 1 3 Limb edema 1 1 0 0 2 Flu-like symptom 2 0 0 0 2 Allergic reaction, unspecified 1 0 0 0 1 Other 9 8 5 4 26 a Each infusion reactions could result in multiple symptoms so that the total number of symptoms (n = 112) exceeded the number of infusion- related events (n = 77). Also, infections led to five of the nine deaths. The most common type of infection was non-tuberculosis bacteria, although viral infections were also common. This agrees with data from the Swedish practice-based registry ARTIS (AntiRheumatic Therapies In Sweden), which indicate that there is a slight increase in the risk of infec- tion in RA patients treated with anti-TNF-α agents but that it is not driven by any particular type of infection [27]. A recent meta-analysis of randomized clinical trials by Leombruno and colleagues, however, did not find an increased risk of serious infections in RA patients treated with recommended doses of anti-TNF-α therapies [16]. Similar to Takeuchi and colleagues [28], we found that older patients were more likely to have infections, although the odds ratio was close to 1.0. It is also note- worthy that all patients that died from infections were at least 69 years old. Finally, although our study confirms that infections are a reason for concern in refractory RA patients, we cannot determine whether the risk for infec- tion or death due to an infection was increased by treat- ment with infliximab. Discussion There were four cases of malignant tumors, three of which led to treatment discontinuation. However, there were no cases of lymphoma, all four were different tumor types, and there were no obvious relations between the incidence of tumors and any of the patient characteris- tics. Infections were also most common during the first 26 weeks of the study. This agrees with the findings of the ARTIS study, where the risk of infection was highest in the first year [27]. We suspect that this was due to the dis- continuation of susceptible patients rather than an adap- tation to the treatment. This is supported by the fact that discontinuation for any AE was most common during the first 26 weeks. Moreover, using data from a registry of British patients, Dixon and colleagues showed that the risk of serious infection is highest in the first six months after the initiation of anti-TNF-α therapies and that the reduction in risk thereafter is associated with physicians excluding patients considered at high risk [41]. Regard- less of the reason for the lower risk for infection with time, some risk is always present, so physicians should remain vigilant during the course of treatment with inf- liximab or any other anti-TNF-α therapy. We also paid close attention to the incidence of cardio- vascular AEs because RA patients are at increased risk [33]. Cardiovascular events accounted for 4 of 74 treat- ment discontinuations, and they were the fourth most common AE overall. They also accounted for two of the nine deaths. Despite the importance of cardiovascular events, there is good evidence that anti-TNF-α therapies reduce the risk in patients with RA to the level in the non- RA population [33-35]. AEs overall, SAEs, and IRs were most common during the first 26 weeks of treatment. We found an association with higher age and the appearance of AEs overall. Also, higher age was a predictor of SAEs, infections, and dis- continuation due to a SAE, but the odds ratios were all close to 1.0. Otherwise, we did not identify significant risk factors for AEs overall, SAEs, infections, or IRs in this study. Prior to beginning the study, we speculated that the use of corticosteroids would reduce the frequency of IRs and increase the frequency of infections. Discussion With regard to infections, of particular concern is the increased risk for tuberculosis in patients treated with infliximab, which is generally thought to be due to a lack of compliance with recommendations to prevent reacti- vation of latent tuberculosis infections [29,30]. In the cur- rent study, there were four cases of tuberculosis (three confirmed, one suspected). All four were in patients with negative Mantoux tests and chest X-rays at screening. One of the confirmed cases of tuberculosis appeared to be a new case caused by exposure to a family member with overt tuberculosis. The remaining could have been new cases of tuberculosis, but they may have also been due to latent infections that went undetected by the screening tests [30]. Interestingly, all four cases of tuber- culosis were in patients taking corticosteroids at baseline, which could have masked the Mantoux test or caused further suppression of the patient's immune system. Regardless of the reasons for these infections, we concur Figure 3 Treatment discontinuations over time. 43 25 6 14 5 21 18 4 22 0 10 20 30 40 50 60 70 80 90 100 Week 0-26 Week 27-50 Week 51-74 Patients discontinuing Elective Inefficacy Safety Figure 3 Treatment discontinuations over time. Delabaye et al. Arthritis Research & Therapy 2010, 12:R121 http://arthritis-research.com/content/12/3/R121 Delabaye et al. Arthritis Research & Therapy 2010, 12:R121 http://arthritis-research.com/content/12/3/R121 Page 9 of 12 with the conclusion of Theis and Rhodes [30] that, despite screening and efforts to treat latent infections, cli- nicians need to carefully monitor for the emergence of tuberculosis infections in patients receiving anti-TNF-α therapies. respectively) in a previous multicenter study carried out in Belgium [39]. This difference was partly due to the fact that dose increases were possible in the previous study but not here. In addition, the current study took place after etanercept and adalimumab became available, so that patients had the option of switching to alternative anti-TNF-α therapies. Thus, patients would have been more likely in the current study to discontinue treatment if they or the investigator were uncomfortable with the AEs or the level of efficacy. In addition to infection, IRs are common in patients treated with anti-TNF-α therapies and are a frequent rea- son for discontinuation [31]. In this study, IRs were the second-most common type of AE. Discussion In nearly half of these cases (42.8%), the IRs caused treatment discontinuation, although, in many cases, the IR causing discontinuation was not considered an SAE. In agreement with Kapetanovic and colleagues [32], age, sex, and HAQ results were not risk factors for IRs. In contrast to their report, however, we did not find an association between IRs and age at diagnosis/onset or longer disease duration. In addition to infection, IRs are common in patients treated with anti-TNF-α therapies and are a frequent rea- son for discontinuation [31]. In this study, IRs were the second-most common type of AE. In nearly half of these cases (42.8%), the IRs caused treatment discontinuation, although, in many cases, the IR causing discontinuation was not considered an SAE. In agreement with Kapetanovic and colleagues [32], age, sex, and HAQ results were not risk factors for IRs. In contrast to their report, however, we did not find an association between IRs and age at diagnosis/onset or longer disease duration. Some early studies suggest that anti-TNF-α agents may increase the risk of malignancies, especially lymphoma [13-15]. However, this is not supported by a more recent meta-analysis of clinical trial data or more recent data from clinical registries [16-18]. Nevertheless, we paid close attention to the appearance of malignant tumors. There were four cases of malignant tumors, three of which led to treatment discontinuation. However, there were no cases of lymphoma, all four were different tumor types, and there were no obvious relations between the incidence of tumors and any of the patient characteris- tics. Treatment discontinuations were most frequent during the first 26 weeks. The AEs most frequently leading to discontinuation were IRs, followed by infections. Baseline characteristics, including age, did not appear to predis- pose patients to discontinuation due to an AE. Higher age was a significant predictor of discontinuation due to an SAE, but the odds ratio was close to 1.0. Similarly, Chevil- lotte-Maillard et al. reported no difference in discontinu- ation rates (median one-year follow-up) or drug survival curves between older and younger patients treated with infliximab [40]. Some early studies suggest that anti-TNF-α agents may increase the risk of malignancies, especially lymphoma [13-15]. However, this is not supported by a more recent meta-analysis of clinical trial data or more recent data from clinical registries [16-18]. Nevertheless, we paid close attention to the appearance of malignant tumors. Discussion Poriau S., Elisa- bethziekenhuis - Sijsele; Dr. Praet J., Aalst; Dr. Raeman F., Jan Palfijnziekenhuis - Merksem; Dr. Ravelingien I., Onze Lieve Vrouwziekenhuis - Aalst; Dr. Ribbens C., CHU Sart Tilman - Liège; Dr. Ronsmans I., Clinique Sainte-Elisa- beth - Namur; Dr. Schatteman L., AZ Sint-Augustinus - Wilrijk; Dr. Schreiber S., CHU Tivoli - La Louvière; Dr. Stappaerts G., AZ Maria Middelares St.Jozef - Gent; Dr. Stasse P., Clinique St-Joseph - Mons; Dr. Stuer A., Heilig Hart Ziekenhuis - Roeselare; Dr. Van Bruwaene F., Heilig Hart Ziekenhuis - Roeselare; Dr. Van Den Berghe M., AZ Zusters van Barmhartigheid - Ronse; Dr. Van Den Bosch F., Elisabethziekenhuis - Sijsele; Dr. Van den Bossche N., Stadskliniek - St.Niklaas; Dr. Van Essche E., Onze Lieve Vrouwziekenhuis - Mechelen; Dr. Van Wanghe P., Virga Jesse Ziekenhuis - Hasselt; Dr. Vanden Berghe M., Hôpit- al St- Thérèse - Montignies-Sur-Sambre; Dr. Vanhoof J., ZOL - Genk; Dr. Vanneuville B., Stedelijk Ziekenhuis - Roeselare; Dr. Villers C., CH Grand Hornu; Dr. Volders P., Reuma Centrum - Genk; Dr. Vroninks P., Salvatorzieken- huis -Hasselt;Dr. Walravens M., Mol; Dr. Williame L., AZ Middelheim - Antwerp; Dr. Wouters M., Parc Leopold - Brussels; Dr. Zmierczak HG., Kliniek St-Elisabeth - Zotte- gem; Prof. Appelboom T., ULB - Hôpital Erasme - Brus- sels; Prof. Boutsen Y., UCL Mont-Godinne; Prof. De Clerck L., UZ Antwerp; Prof. Devogelaer JP., UCL Saint- Luc - Brussels; Prof. E.M. Veys, UZ Gent; Prof. Houssiau F., UCL Saint-Luc - Brussels; Prof. Mielants H., AZ Sint- Augustinus - Wilrijk; Prof. Peretz A., CHU Brugmann - Brussels; Prof. Steinfeld S., ULB - Hôpital Erasme - Brus- sels; Prof. Verbruggen G., Prive Praktijk - Izegem; Prof. Verbruggen L., AZ VUB - Brussels; Prof. Westhovens R., UZ Gasthuisberg - Leuven. oids masked the Mantoux results or increased the risk for tuberculosis infections in these patients by suppressing their immune systems. Acknowledgements The authors would like to thank Dr. Phillip Leventhal (4Clincs, Paris) for assistance in writing this manuscript, and Mrs. Annelies Vanneuville (Denys Research Consul- tants bvba, Gent) for assistance in data management, and Mrs. Hermine Leroi for assistance in data analysis. The members of the REMITRACT study group are Dr. Ackerman C., AZ St-Lucas Gent; Dr. André B., CHU Sart Tilman - Liège; Dr. Badot V., CHU Brugmann - Brussels; Dr. Bailleul Y., CH Institut Bracops site Anderlecht; Dr. Bentin J., RHMS Louis Caty - Baudour; Dr. Berghs H., ZOL - Genk; Dr. Brasseur J.P., Clinique St-Pierre - Ottig- nies; Dr. Castro S., AZ Maria Middelares St.Jozef - Gent; Dr. Cheroutre G., Polikliniek Bond Moyson - Wetteren; Dr. Coigné E., Jan Yperman Ziekenhuis - Ieper; Dr. Cop- pens M., ZOL - Genk; Dr. Corluy L., Virga Jesse Zieken- huis - Hasselt; Dr. Cornet Fr., CHR La Tourelle - Verviers; Dr. Courtois C., Clinique Notre Dame - Tournai; Dr. Cou- tellier P., Clinique Saint Luc - Bouge; Dr. Dall Armellina S., Clinique Notre Dame De Grace - Gosselies; Dr. Daumerie F., Hôpital de Jolimont - Haine-Saint-Paul; Dr. De Brabanter G., AZ Sint Lucas/Sint Jozef - Assebroek; Dr. De Clercq L., AZ Sint-Augustinus - Wilrijk; Dr. De Decker V., CHU André Vésale - Montigny-le-tilleul; Dr. De Graeve B., Maria Middelares - St.Niklaas; Dr. De Vlam K., Sint Andries Ziekenhuis - Tielt; Dr. Declerck K., Imeldaziekenhuis - Mechelen; Dr. Dhondt E., AZ St-Jan - Brugge; Dr. Di Romana S., CHU St-Pierre - Brussels; Dr. Docquier C., Hôpital de Jolimont - Haine-Saint-Paul; Dr. Dufour JP., UCL Saint-Luc - Brussels; Dr. Dumont M., CH Bois Abbaye et Hesbaye - Waremme; Dr. Durez P., UCL Saint-Luc - Brussels; Dr. Engelbeen J.P., Clinique Ste-Anne/St-Rémi - Brussels; Dr. Fernandez Lopez MJ., CHU Brugmann - Brussels; Dr. Francois D., Clinique Europe St-Michel - Brussels; Dr. Geusens P., ZOL - Genk; Dr. Ghyselen G., OCMW Stadskliniek - Lokeren; Dr. Goemaere S., UZ Gent; Dr. Goethals L., AZ Stuyvenberg - Antwerp; Dr. Golstein M., Hôpital César de Paepe - Brussels; Dr. Gyselbrecht L., Aalsters Stedelijk Zieken- huis; Dr. Halleux R., Clinique Sainte-Elisabeth - Heusy; Dr. Herman H., AZ Sint Blasius - Dendermonde; Dr. Her- manns P., AZ Maria Middelares - Gent; Dr. Heuse E., Conclusions In conclusion, we found that, in RA patients treated with infliximab and MTX, discontinuations and AEs occur most frequently during the first 26 weeks of treatment. The study also emphasizes that physicians should care- fully monitor patients for the appearance of infections, including but not limited to tuberculosis and other bacte- rial infections. Discussion Ronsmans I., Clinique Sainte-Elisa- beth - Namur; Dr. Schatteman L., AZ Sint-Augustinus - Wilrijk; Dr. Schreiber S., CHU Tivoli - La Louvière; Dr. Stappaerts G., AZ Maria Middelares St.Jozef - Gent; Dr. Stasse P., Clinique St-Joseph - Mons; Dr. Stuer A., Heilig Hart Ziekenhuis - Roeselare; Dr. Van Bruwaene F., Heilig Hart Ziekenhuis - Roeselare; Dr. Van Den Berghe M., AZ Zusters van Barmhartigheid - Ronse; Dr. Van Den Bosch F., Elisabethziekenhuis - Sijsele; Dr. Van den Bossche N., Stadskliniek - St.Niklaas; Dr. Van Essche E., Onze Lieve Vrouwziekenhuis - Mechelen; Dr. Van Wanghe P., Virga Jesse Ziekenhuis - Hasselt; Dr. Vanden Berghe M., Hôpit- al St- Thérèse - Montignies-Sur-Sambre; Dr. Vanhoof J., ZOL - Genk; Dr. Vanneuville B., Stedelijk Ziekenhuis - Roeselare; Dr. Villers C., CH Grand Hornu; Dr. Volders P., Reuma Centrum - Genk; Dr. Vroninks P., Salvatorzieken- huis -Hasselt;Dr. Walravens M., Mol; Dr. Williame L., AZ Middelheim - Antwerp; Dr. Wouters M., Parc Leopold - Brussels; Dr. Zmierczak HG., Kliniek St-Elisabeth - Zotte- gem; Prof. Appelboom T., ULB - Hôpital Erasme - Brus- sels; Prof. Boutsen Y., UCL Mont-Godinne; Prof. De Clerck L., UZ Antwerp; Prof. Devogelaer JP., UCL Saint- Luc - Brussels; Prof. E.M. Veys, UZ Gent; Prof. Houssiau F., UCL Saint-Luc - Brussels; Prof. Mielants H., AZ Sint- Augustinus - Wilrijk; Prof. Peretz A., CHU Brugmann - Brussels; Prof. Steinfeld S., ULB - Hôpital Erasme - Brus- sels; Prof. Verbruggen G., Prive Praktijk - Izegem; Prof. Verbruggen L., AZ VUB - Brussels; Prof. Westhovens R., UZ Gasthuisberg - Leuven. Additional material Hôpital de la Citadelle - Liège; Dr. Heylen A., Clinique Sainte-Elisabeth - Namur; Dr. Immesoete C., Aalsters Stedelijk Ziekenhuis; Dr. Itzkowitch D., CH Tubize-Niv- elle; Dr. Janssens X., AZ St-Lucas Gent; Dr. Jeukens T., CH Bois Abbaye et Hesbaye - Waremme; Dr. Joos R., Jan Palfijnziekenhuis - Merksem; Dr. Kaiser M-J., CHU Sart Tilman - Liège; Dr. Langenaken C., Virga Jesse Ziekenhuis - Hasselt; Dr. Lefebvre S., CH Mouscron Site Refuge; Dr. Lenaerts J., Virga Jesse Ziekenhuis - Hasselt; Dr. Léon M., CHU Ambroise Pare - Mons; Dr. Luyten H., Volkskliniek E.Moyson - Gent; Dr. Maenaut K., Sint Jozefziekenhuis - Malle; Dr. Maertens M., AZ Damiaan - Oostende; Dr. Maeyaert B., AZ Sint Lucas/Sint Jozef - Assebroek; Dr. Martin F., Hôpital de Warquignies - Boussu; Dr. Moens Ph., Cliniques de l'Europe/Ste Elisabeth - Brussels; Dr. Pater C., Clinique St.Joseph - Arlon; Dr. Discussion However, our analy- sis showed that the use of corticosteroids was not associ- ated with a difference in the likelihood of AEs overall, SAEs, IRs, allergic skin reactions, or infections, nor did it appear to influence the likelihood of discontinuation due to AEs or IRs. These results suggest that patients can con- tinue corticosteroid use during treatment with inflix- imab, if indicated, without increasing the chance for discontinuation or occurrence of an AE, including infec- tions. The results also suggest that corticosteroids do not prevent infliximab-induced IRs. Notably, all four reported cases of tuberculosis were in patients taking corticosteroids at baseline, and all had negative Mantoux tests at screening. Thus, it is possible that the corticoster- One of the key aims of this study was to identify rea- sons for discontinuation in RA patients treated with inf- liximab. In the evaluable population, the continuation rate at 74 weeks was 68.7%. This is comparable with most other studies of daily clinical practice, which have shown one-year continuation rates between 65% and 73% and two-year continuation rates between 67% and 75% [21,36-38]. The continuation rate in the current study was lower than the one-and two-year rates (91% and 81%, Page 10 of 12 Delabaye et al. Arthritis Research & Therapy 2010, 12:R121 http://arthritis-research.com/content/12/3/R121 Delabaye et al. Arthritis Research & Therapy 2010, 12:R121 http://arthritis-research.com/content/12/3/R121 Hôpital de la Citadelle - Liège; Dr. Heylen A., Clinique Sainte-Elisabeth - Namur; Dr. Immesoete C., Aalsters Stedelijk Ziekenhuis; Dr. Itzkowitch D., CH Tubize-Niv- elle; Dr. Janssens X., AZ St-Lucas Gent; Dr. Jeukens T., CH Bois Abbaye et Hesbaye - Waremme; Dr. Joos R., Jan Palfijnziekenhuis - Merksem; Dr. Kaiser M-J., CHU Sart Tilman - Liège; Dr. Langenaken C., Virga Jesse Ziekenhuis - Hasselt; Dr. Lefebvre S., CH Mouscron Site Refuge; Dr. Lenaerts J., Virga Jesse Ziekenhuis - Hasselt; Dr. Léon M., CHU Ambroise Pare - Mons; Dr. Luyten H., Volkskliniek E.Moyson - Gent; Dr. Maenaut K., Sint Jozefziekenhuis - Malle; Dr. Maertens M., AZ Damiaan - Oostende; Dr. Maeyaert B., AZ Sint Lucas/Sint Jozef - Assebroek; Dr. Martin F., Hôpital de Warquignies - Boussu; Dr. Moens Ph., Cliniques de l'Europe/Ste Elisabeth - Brussels; Dr. Pater C., Clinique St.Joseph - Arlon; Dr. Poriau S., Elisa- bethziekenhuis - Sijsele; Dr. Praet J., Aalst; Dr. Raeman F., Jan Palfijnziekenhuis - Merksem; Dr. Ravelingien I., Onze Lieve Vrouwziekenhuis - Aalst; Dr. Ribbens C., CHU Sart Tilman - Liège; Dr. References 1. Venkateshan SP, Sidhu S, Malhotra S, Pandhi P: Efficacy of biologicals in the treatment of rheumatoid arthritis. a meta-analysis. Pharmacology 2009, 83:1-9. 19. Bertoli AM, Strusberg I, Baravalle M, Betelu Z, Calas D, Morales L, Strusberg AM: Rate and causes of infliximab discontinuation in patients with rheumatoid arthritis in a private clinical practice. J Clin Rheumatol 2008, 14:313-317. 2. Roberts LJ, Cleland LG, Thomas R, Proudman SM: Early combination disease modifying antirheumatic drug treatment for rheumatoid arthritis. Med J Aust 2006, 184:122-125. Roberts LJ, Cleland LG, Thomas R, Proudman SM: Early combina 3. Rubbert-Roth A, Finckh A: Treatment options in patients with rheumatoid arthritis failing initial TNF inhibitor therapy: a critical review. Arthritis Res Ther 2009, 11(Suppl 1):S1. 20. Figueiredo IT, Morel J, Sany J, Combe B: Maintenance and tolerability of infliximab in a cohort of 152 patients with rheumatoid arthritis. Clin Exp Rheumatol 2008, 26:18-23. 4. Sizova L: Approaches to the treatment of early rheumatoid arthritis with disease-modifying antirheumatic drugs. Br J Clin Pharmacol 2008, 66:173-178. 21. Wendling D, Materne GE, Michel F, Lohse A, Lehuede G, Toussirot E, Massol J, Woronoff-Lemsi MC: Infliximab continuation rates in patients with rheumatoid arthritis in everyday practice. Joint Bone Spine 2005, 72:309-312. 5. Swierkot J, Szechinski J: Methotrexate in rheumatoid arthritis. Pharmacol Rep 2006, 58:473-492. 5. Swierkot J, Szechinski J: Methotrexate in rheumatoid arthritis. Pharmacol Rep 2006, 58:473-492. 22. Fries JF, Spitz P, Kraines RG, Holman HR: Measurement of patient outcome in arthritis. Arthritis Rheum 1980, 23:137-145. 6. Brennan FM, McInnes IB: Evidence that cytokines play a role in rheumatoid arthritis. J Clin Invest 2008, 118:3537-3545. 6. Brennan FM, McInnes IB: Evidence that cytokines play a role in rheumatoid arthritis. J Clin Invest 2008, 118:3537-3545. rheumatoid arthritis. J Clin Invest 2008, 118:3537-3545 23. Scott DL, Houssien DA: Joint assessment in rheumatoid arthritis. Br J Rheumatol 1996, 35(Suppl 2):14-18. 7. Knight DM, Trinh H, Le J, Siegel S, Shealy D, McDonough M, Scallon B, Moore MA, Vilcek J, Daddona P, Ghraveb J: Construction and initial characterization of a mouse-human chimeric anti-TNF antibody. Mol Immunol 1993, 30:1443-1453. 7. Knight DM, Trinh H, Le J, Siegel S, Shealy D, McDonough M, Scallon B, Moore MA, Vilcek J, Daddona P, Ghraveb J: Construction and initial characterization of a mouse-human chimeric anti-TNF antibody. Mol Immunol 1993, 30:1443-1453. 24. Schaible TF: Long term safety of infliximab. Can J Gastroenterol 2000, 14(Suppl C):29C-32C. 25. References Flendrie M, Creemers MC, Welsing PM, van Riel PL: The influence of previous and concomitant leflunomide on the efficacy and safety of infliximab therapy in patients with rheumatoid arthritis; a longitudinal observational study. Rheumatology (Oxford) 2005, 44:472-478. 8. Lipsky PE, van der Heijde DM, St Clair EW, Furst DE, Breedveld FC, Kalden JR, Smolen JS, Weisman M, Emery P, Feldmann M, Harriman GR, Maini RN: Infliximab and methotrexate in the treatment of rheumatoid arthritis. Anti-Tumor Necrosis Factor Trial in Rheumatoid Arthritis with Concomitant Therapy Study Group. N Engl J Med 2000, 343:1594-1602. 26. Schiff M, Keiserman M, Codding C, Songcharoen S, Berman A, Nayiager S, Saldate C, Li T, Aranda R, Becker JC, Lin C, Cornet PL, Dougados M: Efficacy and safety of abatacept or infliximab vs placebo in ATTEST: a phase III, multi-centre, randomised, double-blind, placebo-controlled study in patients with rheumatoid arthritis and an inadequate response to methotrexate. Ann Rheum Dis 2008, 67:1096-1103. Concomitant Therapy Study Group. N Engl J Med 2000, 343:1594-1602. 9. Maini R, St Clair EW, Breedveld F, Furst D, Kalden J, Weisman M, Smolen J, Emery P, Harriman G, Feldmann M, Lipsky P: Infliximab (chimeric anti- tumour necrosis factor alpha monoclonal antibody) versus placebo in rheumatoid arthritis patients receiving concomitant methotrexate: a randomised phase III trial. ATTRACT Study Group. Lancet 1999, 354:1932-1939. 27. Askling J, Fored CM, Brandt L, Baecklund E, Bertilsson L, Feltelius N, Coster L, Geborek P, Jacobsson LT, Lindblad S, Lysholm J, Rantapaa-Dahlqvist S, Saxne T, van Vollenhoven RF, Klareskog L: Time-dependent increase in risk of hospitalisation with infection among Swedish RA patients treated with TNF antagonists. Ann Rheum Dis 2007, 66:1339-1344. 10. Quinn MA, Conaghan PG, O'Connor PJ, Karim Z, Greenstein A, Brown A, Brown C, Fraser A, Jarret S, Emery P: Very early treatment with infliximab in addition to methotrexate in early, poor-prognosis rheumatoid arthritis reduces magnetic resonance imaging evidence of synovitis and damage, with sustained benefit after infliximab withdrawal: results from a twelve-month randomized, double-blind, placebo- controlled trial. Arthritis Rheum 2005, 52:27-35. 28. Takeuchi T, Tatsuki Y, Nogami Y, Ishiguro N, Tanaka Y, Yamanaka H, Kamatani N, Harigai M, Ryu J, Inoue K, Kondo H, Inokuma S, Ochi T, Koike T: Postmarketing surveillance of the safety profile of infliximab in 5000 Japanese patients with rheumatoid arthritis. Ann Rheum Dis 2008, 67:189-194. 11. Competing interests ID was an employee of Schering-Plough at the time the study was performed and the article was written. FDK received financial support from Schering- Plough and has received research grants from (in alphabetic order): Abbott, Centocor, Roche, Schering-Plough, and UCB. 14. Brown SL, Greene MH, Gershon SK, Edwards ET, Braun MM: Tumor necrosis factor antagonist therapy and lymphoma development: twenty-six cases reported to the Food and Drug Administration. Arthritis Rheum 2002, 46:3151-3158. Delabaye et al. Arthritis Research & Therapy 2010, 12:R121 http://arthritis-research.com/content/12/3/R121 12. Augustsson J, Eksborg S, Ernestam S, Gullstrom E, van Vollenhoven R: Low-dose glucocorticoid therapy decreases risk for treatment-limiting infusion reaction to infliximab in patients with rheumatoid arthritis. Ann Rheum Dis 2007, 66:1462-1466. Author Details 1Department of Immunology, Schering-Plough nv, 73 Rue de Stalle, Brussels 1180, Belgium, 2Ghent University, Department of Rheumatology, Ghent University Hospital, De Pintelaan 185, Ghent, B-9000, Belgium and 319 Avenue des Vieux Amis, Waterloo 1410, Belgium 1Department of Immunology, Schering-Plough nv, 73 Rue de Stalle, Brussels 1180, Belgium, 2Ghent University, Department of Rheumatology, Ghent University Hospital, De Pintelaan 185, Ghent, B-9000, Belgium and 319 Avenue 1Department of Immunology, Schering-Plough nv, 73 Rue de Stalle, Brussels 1180, Belgium, 2Ghent University, Department of Rheumatology, Ghent 1Department of Immunology, Schering-Plough nv, 73 Rue de Stalle, Brussels 1180, Belgium, 2Ghent University, Department of Rheumatology, Ghent University Hospital, De Pintelaan 185, Ghent, B-9000, Belgium and 319 Avenue des Vieux Amis, Waterloo 1410, Belgium 17. Wolfe F, Michaud K: The effect of methotrexate and anti-tumor necrosis factor therapy on the risk of lymphoma in rheumatoid arthritis in 19,562 patients during 89,710 person-years of observation. Arthritis Rheum 2007, 56:1433-1439. University Hospital, De Pintelaan 185, Ghent, B-9000, Belgium and 319 Avenue des Vieux Amis, Waterloo 1410, Belgium Received: 29 October 2009 Revised: 17 March 2010 Accepted: 22 June 2010 Published: 22 June 2010 This article is available from http //arthritis research com/content/12/3/R121 © 2010 Delabaye and De Keyser licensee BioMed Central Ltd This is an open access article distributed under the terms of the Creative Commons Attribution License (http //creativecommons org/licenses/by/2 0) which permits unrestricted use distribution an Arthritis Research & Therapy 2010 12 R121 Received: 29 October 2009 Revised: 17 March 2010 Accepted: 22 June 2010 Published: 22 June 2010 Thi ti l i il bl f htt // th iti h / t t/12/3/R121 © 2010 D l b d D K li Bi M d C t l Ltd Thi i ti l di t ib t d d th t f th C ti C Att ib ti Li (htt // ti /li /b /2 0) hi h it t i t d di t ib ti A th iti R h & Th 2010 12 R121 18. Askling J, Baecklund E, Granath F, Geborek P, Fored M, Backlin C, Bertilsson L, Coster L, Jacobsson LT, Lindblad S, Lysholm J, Rantapaa-Dahlqvist S, Saxne T, van Vollenhoven R, Klareskog L, Feltelius N: Anti-tumour necrosis factor therapy in rheumatoid arthritis and risk of malignant lymphomas: relative risks and time trends in the Swedish Biologics Register. Ann Rheum Dis 2009, 68:648-653. Abbreviations d AE: adverse event; CI: confidence interval; DMARD: disease-modifying anti- rheumatic drug; HAQ: health assessment questionnaire; IR: infusion reaction; MTX: methotrexate; NSAIDs: nonsteroidal anti-inflammatory drugs; RA: rheu- matoid arthritis; SAE: serious adverse event; SJC: swollen joint count; TNF: tumor necrosis factor. 13. Bongartz T, Sutton AJ, Sweeting MJ, Buchan I, Matteson EL, Montori V: Anti-TNF antibody therapy in rheumatoid arthritis and the risk of serious infections and malignancies: systematic review and meta- analysis of rare harmful effects in randomized controlled trials. JAMA 2006, 295:2275-2285. Authors' contributions d d 15. Wolfe F, Michaud K: Lymphoma in rheumatoid arthritis: the effect of methotrexate and anti-tumor necrosis factor therapy in 18,572 patients. Arthritis Rheum 2004, 50:1740-1751. ID and FDK interpreted and analyzed the data and participated in the writing of the manuscript. 16. Leombruno JP, Einarson TR, Keystone EC: The safety of anti-tumour necrosis factor treatments in rheumatoid arthritis: meta and exposure- adjusted pooled analyses of serious adverse events. Ann Rheum Dis 2009, 68:1136-1145. Additional material Additional file 1 Supporting information. This file contains the three supplemental tables. Supplemental table 1 gives details on opportunistic infections during the study, Supplemental table 2 on tuberculosis cases during the study, Supplemental table 3 on tumor cases during the study, and supplemental table 4 on deaths during the study. Page 11 of 12 Delabaye et al. Arthritis Research & Therapy 2010, 12:R121 http://arthritis-research.com/content/12/3/R121 Delabaye et al. Arthritis Research & Therapy 2010, 12:R121 http://arthritis-research.com/content/12/3/R121 References Westhovens R, Yocum D, Han J, Berman A, Strusberg I, Geusens P, Rahman MU: The safety of infliximab, combined with background treatments, among patients with rheumatoid arthritis and various comorbidities: a large, randomized, placebo-controlled trial. Arthritis Rheum 2006, 54:1075-1086. 29. Gomez-Reino JJ, Carmona L, Valverde VR, Mola EM, Montero MD: Treatment of rheumatoid arthritis with tumor necrosis factor inhibitors may predispose to significant increase in tuberculosis risk: a Page 12 of 12 multicenter active-surveillance report. Arthritis Rheum 2003, 48:2122-2127. multicenter active-surveillance report. Arthritis Rheum 2003, 48:2122-2127. 30. Theis VS, Rhodes JM: Review article: minimizing tuberculosis during anti-tumour necrosis factor-alpha treatment of inflammatory bowel disease. Aliment Pharmacol Ther 2008, 27:19-30. 31. Du Pan SM, Dehler S, Ciurea A, Ziswiler HR, Gabay C, Finckh A: Comparison of drug retention rates and causes of drug discontinuation between anti-tumor necrosis factor agents in rheumatoid arthritis. Arthritis Rheum 2009, 61:560-568. 32. Kapetanovic MC, Larsson L, Truedsson L, Sturfelt G, Saxne T, Geborek P: Predictors of infusion reactions during infliximab treatment in patients with arthritis. Arthritis Res Ther 2006, 8:R131. 33. Wolfe F, Michaud K: Heart failure in rheumatoid arthritis: rates, predictors, and the effect of anti-tumor necrosis factor therapy. Am J Med 2004, 116:305-311. 34. Jacobsson LT, Turesson C, Gulfe A, Kapetanovic MC, Petersson IF, Saxne T, Geborek P: Treatment with tumor necrosis factor blockers is associated with a lower incidence of first cardiovascular events in patients with rheumatoid arthritis. J Rheumatol 2005, 32:1213-1218. 35. Listing J, Strangfeld A, Kekow J, Schneider M, Kapelle A, Wassenberg S, Zink A: Does tumor necrosis factor alpha inhibition promote or prevent heart failure in patients with rheumatoid arthritis? Arthritis Rheum 2008, 58:667-677. 36. Zink A, Listing J, Kary S, Ramlau P, Stoyanova-Scholz M, Babinsky K, von Hinueber U, Gromnica-Ihle E, Wassenberg S, Antoni C, Herzer P, Kekow J, Schneider M, Rau R: Treatment continuation in patients receiving biological agents or conventional DMARD therapy. Ann Rheum Dis 2005, 64:1274-1279. 37. Flendrie M, Creemers MC, Welsing PM, den Broeder AA, van Riel PL: Survival during treatment with tumour necrosis factor blocking agents in rheumatoid arthritis. Ann Rheum Dis 2003, 62(Suppl 2):ii30-33. 38. Geborek P, Crnkic M, Petersson IF, Saxne T: Etanercept, infliximab, and leflunomide in established rheumatoid arthritis: clinical experience using a structured follow up programme in southern Sweden. Ann Rheum Dis 2002, 61:793-798. 39. Vander Cruyssen B, Van Looy S, Wyns B, Westhovens R, Durez P, Van den Bosch F, Mielants H, De Clerck L, Peretz A, Malaise M, Verbruggen L, Vastesaeger N, Geldhof A, Boullart L, De Keyser F: Four-year follow-up of infliximab therapy in rheumatoid arthritis patients with long-standing refractory disease: attrition and long-term evolution of disease activity. Arthritis Res Ther 2006, 8:R112. y 40. Chevillotte-Maillard H, Ornetti P, Mistrih R, Sidot C, Dupuis J, Dellas JA, Tavernier C, Maillefert JF: Survival and safety of treatment with infliximab in the elderly population. Rheumatology (Oxford) 2005, 44:695-696. doi: 10.1186/ar3058 Cite this article as: Delabaye et al., 74-week follow-up of safety of infliximab in patients with refractory rheumatoid arthritis Arthritis Research & Therapy 2010, 12:R121 multicenter active-surveillance report. Arthritis Rheum 2003, 48:2122-2127. 40. Chevillotte-Maillard H, Ornetti P, Mistrih R, Sidot C, Dupuis J, Dellas JA, Tavernier C, Maillefert JF: Survival and safety of treatment with infliximab in the elderly population. Rheumatology (Oxford) 2005, 44:695-696. 41. Dixon WG, Symmons DP, Lunt M, Watson KD, Hyrich KL, Silman AJ: Serious infection following anti-tumor necrosis factor alpha therapy in patients with rheumatoid arthritis: lessons from interpreting data from observational studies. Arthritis Rheum 2007, 56:2896-2904. doi: 10.1186/ar3058 Cite this article as: Delabaye et al., 74-week follow-up of safety of infliximab in patients with refractory rheumatoid arthritis Arthritis Research & Therapy 2010, 12:R121 doi: 10.1186/ar3058 Cite this article as: Delabaye et al., 74-week follow-up of safety of infliximab in patients with refractory rheumatoid arthritis Arthritis Research & Therapy 2010, 12:R121
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A Transdisciplinary Approach to Characterize Hydrological Controls on Groundwater-Dependent Ecosystem Health
Frontiers in environmental science
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Lawrence Berkeley National Laboratory LBL Publications Title A Transdisciplinary Approach to Characterize Hydrological Controls on Groundwater- Dependent Ecosystem Health Permalink https://escholarship.org/uc/item/6bc6791n Authors Rohde, Melissa M Sweet, Sara B Ulrich, Craig et al. Publication Date 2019 DOI 10.3389/fenvs.2019.00175 Copyright Information This work is made available under the terms of a Creative Commons Attribution License available at https://creativecommons.org/licenses/by/4.0/ Peer reviewed Lawrence Berkeley National Laboratory LBL Publications Title A Transdisciplinary Approach to Characterize Hydrological Controls on Groundwater- Dependent Ecosystem Health Permalink https://escholarship.org/uc/item/6bc6791n Authors Rohde, Melissa M Sweet, Sara B Ulrich, Craig et al. Publication Date 2019 DOI 10.3389/fenvs.2019.00175 Copyright Information This work is made available under the terms of a Creative Commons Attribution License available at https://creativecommons.org/licenses/by/4.0/ Peer reviewed Lawrence Berkeley National Laboratory LBL Publications Title A Transdisciplinary Approach to Characterize Hydrological Controls on Groundwater- Dependent Ecosystem Health Permalink https://escholarship.org/uc/item/6bc6791n Authors Rohde, Melissa M Sweet, Sara B Ulrich, Craig et al. Publication Date 2019 DOI 10.3389/fenvs.2019.00175 Copyright Information This work is made available under the terms of a Creative Commons Attribution License available at https://creativecommons.org/licenses/by/4.0/ Peer reviewed Lawrence Berkeley National Laboratory A Transdisciplinary Approach to Characterize Hydrological Controls on Groundwater- Dependent Ecosystem Health 10.3389/fenvs.2019.00175 Copyright Information Copyright Information This work is made available under the terms of a Creative Commons Attribution License, available at https://creativecommons.org/licenses/by/4.0/ This work is made available under the terms of a Creative Commons Attribution License, available at https://creativecommons.org/licenses/by/4.0/ Peer reviewed Peer reviewed eScholarship.org Powered by the California Digital Library University of California Powered by the California Digital Library University of California A Transdisciplinary Approach to Characterize Hydrological Controls on Groundwater-Dependent Ecosystem Health Sustainable groundwater management provides an opportunity for environmental water needs to be considered and secured by establishing appropriate groundwater thresholds. Ecosystems that require access to groundwater for some or all their water requirements are referred to as groundwater dependent ecosystems (GDEs). However, large data gaps often exist around the cause-and-effect relationships between groundwater conditions and the impacts they have on GDEs. These data gaps are largely attributed to a lack of shallow monitoring wells near GDEs, and a lack of practical biological metrics to characterize ecosystem health. This transdisciplinary study explores the use of geophysics (electrical resistivity tomography) to fill in our understanding of shallow subsurface soil-hydrological conditions within GDEs. In addition, we develop an approach to characterize ecosystem health within GDEs, using groundwater-dependent vegetation (phreatophytes) as indicators. Ten vegetation variables were used to characterize six biological indicators—growth, diversity, recruitment, structure, native plant dominance, and survivorship—which were used to infer ecosystem health conditions. Health indicators for groundwater-dependent vegetation were found to directly correlate with subsurface conditions, where greater groundwater availability (higher soil moisture content and shallower groundwater levels) was associated with “healthier” vegetation. This study provides a new approach to integrate hydrological, geophysical, and biological data to strengthen monitoring programs and inform water resource management decisions. Reviewed by: Reviewed by: Nitin Kaushal, World Wide Fund for Nature, India Josep Mas-Pla, Catalan Institute for Water Research, Spain *Correspondence: Melissa M. Rohde melissa.rohde@tnc.org Specialty section: This article was submitted to Freshwater Science, a section of the journal Frontiers in Environmental Science Keywords: groundwater dependent ecosystem, electrical resistivity tomography, groundwater, riparian forest, ecosystem health, sustainable groundwater management, biological response functions, vegetation surveys Received: 29 January 2019 Accepted: 16 October 2019 Published: 06 November 2019 INTRODUCTION Sustainable groundwater management policies worldwide are increasingly incorporating environmental considerations (Rohde et al., 2017), creating new opportunities to maintain and preserve ecosystems. Groundwater-dependent ecosystems (GDEs), which are species and ecosystems maintained by direct or indirect access to groundwater, offer a wide range of ecosystem services that benefit our economy and society such as soil preservation, water purification, carbon sequestration, flood control, pollination of crops, and recreational opportunities [Schuyt and Brander, 2004; Blevins and Aldous, 2011; Water Land Ecosystems (WLE) and CRPO, 2015]. Sustainable groundwater management policies worldwide are increasingly incorporating environmental considerations (Rohde et al., 2017), creating new opportunities to maintain and preserve ecosystems. Groundwater-dependent ecosystems (GDEs), which are species and ecosystems maintained by direct or indirect access to groundwater, offer a wide range of ecosystem services that benefit our economy and society such as soil preservation, water purification, carbon sequestration, flood control, pollination of crops, and recreational opportunities [Schuyt and Brander, 2004; Blevins and Aldous, 2011; Water Land Ecosystems (WLE) and CRPO, 2015]. Powered by the California Digital Library University of California eScholarship.org eScholarship.org ORIGINAL RESEARCH published: 06 November 2019 doi: 10.3389/fenvs.2019.00175 Edited by: Sergi Sabater, University of Girona, Spain Citation: Rohde MM, Sweet SB, Ulrich C and Howard J (2019) A Transdisciplinary Approach to Characterize Hydrological Controls on Groundwater-Dependent Ecosystem Health. Front. Environ. Sci. 7:175. doi: 10.3389/fenvs.2019.00175 November 2019 | Volume 7 | Article 175 Frontiers in Environmental Science | www.frontiersin.org Hydrological Controls on Groundwater-Dependent Ecosystem Health Rohde et al. would otherwise be isolated from deeper aquifers by attenuating recharge rates and flow pathways within unconfined aquifers and thereby supporting gaining conditions in streams (Palkovics et al., 1975; Fleckenstein et al., 2006; Rassam et al., 2006; Niswonger and Fogg, 2008). This is the particular case for GDEs in regions where large seasonal or interannual fluctuations occur in the water table of unconfined regional aquifers. Figure 1 provides a conceptual model of how large seasonal fluctuations in the position of the water table within an aquifer can support perched groundwater near a seasonally intermittent river. While perched groundwater itself cannot directly be managed due to its position in the vadose zone, the water table position within the aquifer, and its interactions with surface water can be managed (via pumping rate restrictions, restricted pumping at certain depths, restricted pumping around GDEs, well density rules, managed aquifer recharge projects) to prevent adverse impacts to ecosystems due to changes in groundwater quality and quantity. The presence of groundwater and its interconnections with surface water provide critical habitat conditions for a wide range of species, including rare and endangered species, by sustaining instream flows and providing access to groundwater through the rooting network. However, as humans increasingly depend upon groundwater for irrigation and drinking water supplies (Wada et al., 2012), this reliable water source for GDEs is threatened (Gleeson et al., 2015), especially during dry summer months of Mediterranean climates and drought years. As water managers work toward bringing groundwater basins into balance under sustainable groundwater policies, there is a need for practical approaches to monitor how ecosystems are responding to changing groundwater conditions and determine what groundwater thresholds protect GDEs. GDEs can rely on groundwater occurring near, on, or within the ground surface. Riparian vegetation within GDEs can access groundwater by either: (1) hydraulically lifting groundwater from the water table via capillary action to fill pore spaces in the vadose zone; or (2) accessing soil water in the unsaturated zone residual from seasonal water table fluctuations. 1ftp://ftp.consrv.ca.gov/pub/dmg/rgmp/Prelim_geo_pdf/Lodi_100K_prelim.pdf 2https://casoilresource.lawr.ucdavis.edu/soilweb-apps/ Citation: Only more recently has geophysics been used to characterize and monitor the interaction between subsurface soil moisture and plant roots (Binley and Kemna, 2005; Robinson et al., 2008, 2012; Schwartz et al., 2008; Nijland et al., 2010; Ma et al., 2014; Hübner et al., 2015; Cassiani et al., 2016). ERT was more specifically used in this study to develop a subsurface conceptual model beneath each GDE. FIGURE 2 | Study Site Map: Cosumnes River Preserve, Sacramento County, California. p To sustainably manage groundwater for GDEs, baselines and thresholds need to be established to prevent groundwater conditions from having impacts on ecosystem conditions. While numerous field-based studies have investigated the short- and long-term impacts of groundwater pumping on individual biological responses (i.e., growth, reproduction, recruitment, ecosystem structure, ecosystem function, and survivorship) for individual groundwater-dependent species, there are fewer studies that examine multiple biological responses across multiple groundwater-dependent species (Costanza and Mageau, 1999; Eamus et al., 2015). Integrating ecosystem- scale biological indicators into water management monitoring programs can provide water managers the ability to integrate biological concerns into basin-wide hydrological monitoring efforts. In combination with hydrological data, biological data provides an opportunity for water managers to assess the cause-and-effect relationships between the groundwater conditions and ecosystem-scale biological responses. Since it can be onerous to examine the biological response of all organisms within an ecosystem, groundwater-dependent vegetation is investigated in this study as a practical proxy for monitoring ecosystem-scale changes in GDE health. This is because changes in groundwater conditions impact not only the health of plants themselves, but also subsequently impact the food supply and habitat conditions for animals within the ecosystem. However, if a GDE is a seep or spring with little vegetation associated with it or there are particular focal groundwater-dependent species, then other proxies may be more appropriate. FIGURE 2 | Study Site Map: Cosumnes River Preserve, Sacramento County, California. hydrology, geophysics, and ecology to better understand how subsurface conditions can influence GDE health. Citation: Characterizing groundwater reliance in GDEs can be challenging, especially in river environments where groundwater and surface water interactions occur around heterogeneous sedimentary units that support perched groundwater, such as clay-rich aquitards formed by fluvial deposits. Clay lenses in the subsurface that support perched groundwater can contribute an important groundwater supply for riparian ecosystems and wetlands that Near-surface aquifer environments, especially at the interface of groundwater and surface water are difficult to capture in regional-scale groundwater numerical models typically used by water managers for water balancing and management. Alternatively, geophysics—specifically electrical resistivity tomography (ERT)—provides the opportunity to investigate subsurface conditions over small and large spatial scales that are applicable to understanding subsurface conditions in shallow portions of the aquifer. ERT is a well-established geophysical technique and has been used to investigate subsurface lithology FIGURE 1 | Conceptual model of how seasonal fluctuations in the water table and its interactions with surface water can support perched groundwater availability near intermittent rivers for GDEs in (A) Wet season and (B) Dry season. FIGURE 1 | Conceptual model of how seasonal fluctuations in the water table and its interactions with surface water can support perched groundwater availability near intermittent rivers for GDEs in (A) Wet season and (B) Dry season. FIGURE 1 | Conceptual model of how seasonal fluctuations in the water table and its interactions with surface water can support perched groundwater availability near intermittent rivers for GDEs in (A) Wet season and (B) Dry season. Frontiers in Environmental Science | www.frontiersin.org Frontiers in Environmental Science | www.frontiersin.org Frontiers in Environmental Science | www.frontiersin.org November 2019 | Volume 7 | Article 175 2 Hydrological Controls on Groundwater-Dependent Ecosystem Health Rohde et al. (Tabbagh et al., 2000; Samouëlian et al., 2005; Sudha et al., 2009) and moisture state (Rhoades et al., 1976; Kean et al., 1987; Daily et al., 2010). Only more recently has geophysics been used to characterize and monitor the interaction between subsurface soil moisture and plant roots (Binley and Kemna, 2005; Robinson et al., 2008, 2012; Schwartz et al., 2008; Nijland et al., 2010; Ma et al., 2014; Hübner et al., 2015; Cassiani et al., 2016). ERT was more specifically used in this study to develop a subsurface conceptual model beneath each GDE. (Tabbagh et al., 2000; Samouëlian et al., 2005; Sudha et al., 2009) and moisture state (Rhoades et al., 1976; Kean et al., 1987; Daily et al., 2010). Frontiers in Environmental Science | www.frontiersin.org Study Site Qhb is a basin deposit consisting of fine-grained sediments from the late Holocene that were generally deposited with horizontal stratification in topographic lows. The study sites are underlain by the Columbia, Cosumnes, and San Joaquin soil units. Both the Cosumnes and San Joaquin typical pedons are silty loams and loams, compared to a typical Columbia pedon that is a fine sandy loam. All of these soil types are typical of 0–2% slopes, moderately to poorly drained, and occur along the Cosumnes River floodplain. current from the instrument into the ground through electrodes (metal stakes inserted into the ground) along a profile. The change in the potential voltage as the current travels through the ground is measured at other adjacent electrode pairs along the profile (for more detail see Reynolds, 2011). Alternating combinations of the electrodes results in large resistivity datasets (thousands of measurements) that are collected in a relatively short time period. The resulting resistivity distributions are inverted to get the true spatial distribution of resistivity within the subsurface that describes the actual soil and moisture distributions. This results in ERT images that map how resistive the subsurface based on how quickly the electrical pulses return to the sensors at the land surface. The flow of current through the ground is controlled by the water content and soil type, and can be influenced by rapid temperature change or salinity, if present. Seven ERT profiles were collected in total: one in Tall Forest, two in Shaw Forest, two in Castello Forest, and two at the Oneto-Denier site (Figure 3). Four ERT profiles (one in Tall, one in Shaw, and two at Castello) were collected in September 2016; and, two in Oneto-Denier and one in Shaw Forest in October 2016. ERT data was collected at the end of the summer dry season, in September 2016 and October 2016, to capture subsurface conditions when the riparian forests are most reliant on groundwater. This timing also circumvents any subsurface moisture irregularities due to rewetting fronts, because (1) no rain fell for the previous ∼5 months due to the strongly seasonal Mediterranean climate, and (2) the relatively low elevation of the headwaters precluded substantial snowmelt effects on river flow. ERT data collected in September used a Multi-Phase Technologies (MPT) eight-channel resistivity system with 128 electrodes and 1-m electrode spacing. Study Site The Cosumnes River drains ∼3,400 km2 and flows 129 km westward from its headwaters at ∼2,200 m in California’s Sierra Nevada Mountains toward its outlet in the Sacramento-San Joaquin Delta. Within the study reach (Figure 2), the river follows the boundary between two administratively defined groundwater basins: South American Basin (Sacramento River Hydrologic Region) and Cosumnes Basin (San Joaquin River Hydrologic Region). Human reliance on groundwater for agricultural and domestic use in both basins has substantially lowered regional groundwater levels, creating two cones of depression in the groundwater basins adjacent to the Cosumnes River. Both basins are subject to California’s Sustainable Groundwater Management Act of 2014 (SGMA). This study explores the health of three groundwater- dependent riparian forests along an interconnected surface water body within groundwater basins with an unconfined aquifer, which is not bounded on top by an aquitard and the upper surface of the saturated zone is the water table. By monitoring vegetative growth, species diversity, regenerative capacity (sapling recruitment), native plant density, vegetative structure (strata), and survivorship (canopy cover remaining over time), we explore whether hydrological conditions in the subsurface are correlated with the health of GDEs. The objectives of this paper are to: (1) characterize shallow subsurface hydrological conditions in each forest using ERT, (2) identify practical biological indicators to assess the health of GDEs, and (3) evaluate how differences in hydrological conditions correlate to health indicators for groundwater-dependent riparian forests. These objectives are intended to illustrate how discipline-specific tools can be combined to solve a common problem in sustainable groundwater management. The research presented in this paper adopts this transdisciplinary approach to bridge the fields of A soil and geological evaluation of the study sites along the Cosumnes River was completed using USGS and CA Geological Survey maps1 and the SoilWeb interactive soil maps2 The local November 2019 | Volume 7 | Article 175 3 Hydrological Controls on Groundwater-Dependent Ecosystem Health Rohde et al. geology is dominated by Quaternary Period unconsolidated clays, silts, and sands deposited during the Holocene Epoch. The CA Geological Survey map shows that two deposits dominate the study area, Qha and Qhb; both are alluvial. Qha is an undivided deposit on fans, terraces, or in basins, and consists of sand, gravel, and silts that are poorly to moderately sorted. Electrical Resistivity Tomography Electrical resistivity tomography is a geophysical technique for imaging subsurface environments by transmitting electrical Study Site ERT data collected in October again used an MPT resistivity system, but with 112 electrodes and 1.5-m electrode spacing. The average time to collect a full dataset was ∼2 h or less. A maximum current of 2,000 milliamps (mA) and 400 volts (V) was set during data acquisition, but the system automatically optimizes the injected current if less is needed; on average 42 mA and 140 V were injected during each measurement using a dipole-dipole configuration with 100% reciprocals. The ERT data were inverted using the BERT inversion code (Gunther and Rucker, 2006), which is based on a finite-element model that discretizes the subsurface as a tetrahedral mesh with a grid cell spacing equal to ½ the electrode spacing. All ERT profiles were inverted using a flat surface, since topographic changes along each profile were <30 cm and the dense tree canopy prevented the use of a high- accuracy Global Positioning System (GPS). ERT data of low quality, defined as a measured potential <2 mV, were removed from each data set along with reciprocal errors >5%, which resulted in <10% of data removal from each data set. Model convergence resulted in a mean absolute difference (MAD) error of <6% for all ERT profiles between the measured and modeled data. The Cosumnes River Preserve (Preserve) consists of over 20,000 ha of wildlife habitat that includes riparian forests, seasonal wetlands, grasslands, and habitat for birds migrating along the Pacific Flyway (Kleinschmidt Group, Inc., 2008). Three riparian stands were included in this study: Castello Forest (40 ha), Shaw Forest (60 ha), and Tall Forest (52 ha). Each of these riparian forest stands have been identified in the Natural Communities Commonly Associated with Groundwater Dataset3 (NC Dataset), which is hosted by the California Department of Water Resources (DWR). The NC dataset is a compilation of 48 publicly available State and Federal agency datasets that maps vegetation, wetlands, springs, and seeps that are commonly associated with groundwater in California (Klausmeyer et al., 2018). The overstory is dominated by valley oak (Quercus lobata) in all three forest stands, but the understory differs. The understory in Castello Forest is heavily dominated by non-native winter annual grasses, with very few shrubs or young trees. In contrast, the understory at Shaw and Tall Forests is multi-layered, containing young trees, shrubs, vines, and herbaceous plants. Hydrologic Data Six groundwater monitoring wells (Figure 2) were selected for this study to corroborate groundwater levels and lithological data with the ERT results. One well (MW2) is within Shaw Forest and two wells (MW5 and MW9) are within the Oneto-Denier site (open land within the Preserve). The remaining three wells are historic groundwater monitoring wells from DWR’s Water Data Library4 two near Castello Forest (06N06E28C002M and 06N06E29K001M) and one near Tall Forest (05N05E28L003M). Precipitation data were accessed using the PRISM (Parameter- elevation Regressions on Independent Slopes Model) Monthly Spatial Climate Dataset5, produced by the PRISM Climate Group at Oregon State University. Electrical Resistivity Tomography 3https://gis.water.ca.gov/app/NCDatasetViewer/ 4http://wdl.water.ca.gov/waterdatalibrary/ 5https://developers.google.com/earth-engine/datasets/catalog/ OREGONSTATE_PRISM_AN81m Vegetation Monitoring 3https://gis.water.ca.gov/app/NCDatasetViewer/ 4http://wdl.water.ca.gov/waterdatalibrary/ 5https://developers.google.com/earth-engine/datasets/catalog/ OREGONSTATE_PRISM_AN81m Vegetation data were collected during the summer of 2016 as part of a multi-year vegetation monitoring program. Crown dieback calculations also relied on canopy cover data collected during November 2019 | Volume 7 | Article 175 Frontiers in Environmental Science | www.frontiersin.org 4 Hydrological Controls on Groundwater-Dependent Ecosystem Health Rohde et al. FIGURE 3 | Location of ERT profiles, monitoring wells, and vegetation macroplots at the four study sites: (A) Shaw Forest and Oneto-Denier, (B) Castello Forest, (C) Tall Forest. GURE 3 | Location of ERT profiles, monitoring wells, and vegetation macroplots at the four study sites: (A) Shaw Forest and Oneto-Denier, (B) Castello Forest, (C) all Forest. monitoring wells, and vegetation macroplots at the four study sites: (A) Shaw Forest and Oneto-Denier, (B) Castello Forest, (C) FIGURE 3 | Location of ERT profiles, monitoring wells, and vegetation macroplots at the four study sites: (A) Shaw Forest and Oneto-Denier, (B) Castello Forest, (C) Tall Forest. FIGURE 3 | Location of ERT profiles, monitoring wells, and vegetation macroplots at the four study sites: (A) Shaw Forest and O Tall Forest Model C, Robert E. Lemmon, Forest Densiometers). Diameter at breast height (DBH) was recorded for all mature tree individuals ≥135 cm tall (Bernhardt and Swiecki, 1991). The number of trees that were saplings (defined arbitrarily as those between 50 and 135 cm tall) and young trees (DBH of 0.1 to 10 cm) were also recorded by species. the summer of 2013. Each forest stand was sampled with evenly spaced, permanent 20 × 20 m macroplots. We visually estimated absolute vascular plant cover by species within seven strata that were based on a simplified version of the California Wildlife Habitat Relationships protocol (CDFW, 1988) and categorized as: (1) herb, (2) small shrub (0–2 m tall), (3) tall shrub (>2 m tall), (4) tree seedling (<0.5 m tall), (5) understory tree (0.5–<10 m tall), (6) overstory tree (≥10 m tall), and (7) woody vine. For percent cover calculations, the cover class values were first converted to their midpoints (Table 1). Total canopy cover per macroplot was the mean of four spherical densiometer measurements taken at the center of the macroplot, one facing in each of the four cardinal directions (according to the manufacturer protocol; Frontiers in Environmental Science | www.frontiersin.org Growth The amount of vegetative canopy cover in the overstory was used to characterize growth. Growth was quantified using a spherical densiometer, which is a handheld instrument with a spherical-shaped mirror on which small squares are engraved to assist in determining the amount of tree canopy in the mirror’s reflection (Strickler, 1959). Canopy cover represents the amount of overstory tree biomass that exists at a given point in time. It is a relative value and can range from 0 to 100%, where higher percentages denote denser growth. ecosystem can be characterized as one that is sustainable— having the ability to “maintain its structure (organization) and function (vigor) over time in face of external stress (resilience)” (Costanza and Mageau, 1999). In general, stress to ecosystems caused by changes in groundwater availability can influence six key ecological processes: growth, reproduction, recruitment, mortality, ecosystem structure, and ecosystem function (Eamus et al., 2006b). In response to stress, the response functions of native plants and aquatic ecosystems follow a reasonably predictable and progressive series of events that cascade across molecular, individual, landscape, and ecosystem scales (Davies and Jackson, 2006; Eamus et al., 2006a; USEPA, 2016). For vegetation, a natural progression in response to insufficient water availability would begin with stomatal closure, resulting in a reduction in transpiration and photosynthesis. If water stress persists, xylem embolism can result in reductions in growth rates and contribute to die-back. Reduced growth would then subsequently result in a reduction in reproduction (seed set) and recruitment (sapling growth) processes that are necessary for forest succession to occur. In extreme cases of water stress, the absence of growth and recruitment of younger plants may reduce the biomass physically present in various elevations above the ground surface. The absence may also create the opportunity for new species with different growth forms (e.g., grasses instead of shrubs) to populate the area, thus changing the ecosystem structure (Eamus et al., 2006a). This could then result in the alteration of ecosystem function, since changes in ecosystem structure (the species composition and diversity) could change the functional traits expressed by individual species where the absence of key species could alter ecosystem processes, such as nutrient cycling, predator-prey relationships, and competition for resources (Chapin, 1997). Health Indicators Ecosystems are complex systems composed of living organisms interacting with each other and their environment (e.g., soil, water, and air). The health of an ecosystem is a measure of its overall performance resulting from the biological responses of individual species and their interaction with each other. A healthy November 2019 | Volume 7 | Article 175 Frontiers in Environmental Science | www.frontiersin.org Hydrological Controls on Groundwater-Dependent Ecosystem Health Rohde et al. TABLE 1 | Classes used to record the visual estimation of percent cover for each plant species as well as each stratum as a whole. TABLE 1 | Classes used to record the visual estimation of percent cover for each plant species as well as each stratum as a whole. Percent cover (%) Midpoint (%) <1 0.5 1 to <5 3 5 to <25 15 25 to <50 37.5 50 to <75 62.5 75 to <95 85 >95 97.5 The midpoint value was used to represent each cover class during quantitative analyses. TABLE 1 | Classes used to record the visual estimation of percent cover for each plant species as well as each stratum as a whole. Percent cover (%) Midpoint (%) <1 0.5 1 to <5 3 5 to <25 15 25 to <50 37.5 50 to <75 62.5 75 to <95 85 >95 97.5 The midpoint value was used to represent each cover class during quantitative analyses. the open-source software R (R Development Core Team, 2008). Mean values for each vegetation health indicator were compared between forests using a one-way ANOVA followed by the Tukey HSD statistical test. This post-hoc test was performed using the glht() function in the multcomp package (Hothorn et al., 2017). This parametric statistical test was applied using the argument vcov=vcocHC for its robustness and ability to work with unbalanced group sizes, non-normality, and heteroscedasticity (Herberich et al., 2010). Diversity Th Sh The Shannon-Wiener Evenness Index, which incorporates both species richness and the abundance of each species, was used to characterize diversity. The index represents the relative abundance of different species comprising the richness of an area. The index for each forest stand was calculated using the following Shannon-Wiener Evenness Index equation: Hj = − s X i=1 piln pi  where for each macroplot (j), H is the Shannon-Wiener Evenness Index value, S is the total number of species (richness), and pi is the proportional cover of each species (i) to the total cover of all species in the macroplot. Each index value, which varies between 0 and 1, was converted into a percentile value that ranges between 0 and 100%, where higher percentages denote greater species richness and abundance. Frontiers in Environmental Science | www.frontiersin.org November 2019 | Volume 7 | Article 175 Hydrologic Conditions Figure 4 shows precipitation by month and groundwater levels for three wells from the mid-1960s through August 2019. Historical depth to groundwater (defined as the position of the water table relative to the ground surface) near Castello Forest has ranged between 9.0 and 25.2 m at 06N06E28C002M (Figure 4B) and 5.1 and 23.7 m at 06N06E29K001M (Figure 4C), and near Tall forest has ranged between 0.5 and 3.7 m at 05N05E28L003M (Figure 4D). Depth to groundwater in the unconfined aquifer at four of the ERT sites (ERT-P1, ERT-P2, ERT-P5, and ERT-P6) fluctuated between 6.2 and 14.0 m at MW5, 1.5 and 12.0 m at MW9, and 4.2 and 13.1 m at MW2 (Figure 5), since groundwater data collection began in December 2012. At all three monitoring wells within the study area, depth to groundwater was deepest after the dry summer season and before the rainy winter season. Depth to groundwater gradually increased between 2012 and 2016, which corresponds to the historic drought conditions California experienced during this period. At the time of ERT data collection, depth to groundwater was 11.6 m at ERT-P1, 10.0 m at ERT-P2, and 12.5 m at ERT-P6. Structure Ecosystem structure is generally defined as the community of living organisms coexisting in conjunction with abiotic components (e.g., soil, air, and water). In most habitats, vegetation provides the main structure of the environment (Rutten et al., 2015). More vertical structure (or vertical layering) creates habitat complexity that can support a greater vertical distribution of birds (Pearson, 1971), mammals (Grelle, 2003), and insects (Schulze et al., 2001). Vertical stratification, or the number of layers (strata) present, was used to characterize ecosystem structure and was calculated using the following equation: Regeneration The number of saplings (defined in this study as tree individuals either 50–135 cm tall or with DBH <10 cm) present was used to characterize regeneration. The height and DBH of plants were used to reflect age, where smaller trees are younger than larger ones. At a given time, the presence of trees at different sizes, particularly smaller ones (saplings), indicates that recruitment is occurring. Regeneration was calculated using the following equation: To characterize, infer, and spatially compare health conditions between forest stands in this study, six indicators were derived from the vegetation survey data: growth (species) diversity, regeneration, structure, native plant dominance, and survivorship. A brief description of the rationale and assumptions used to define each health indicator, as well as how vegetation survey data were used to quantify each indicator for this study, is provided in the subsections below. Rj = Sapj Sapj + YTj + MTj where for each macroplot (j), R is Regeneration, Sap is the number of saplings, YT is the number of young trees (DBH 10–25 cm), and MT is the number of mature trees (DBH >25 cm). Regeneration was converted into a percentile value that The health indicators determined for each forest were statistically compared to the other forests in the study using November 2019 | Volume 7 | Article 175 6 Hydrological Controls on Groundwater-Dependent Ecosystem Health Rohde et al. ranges between 0 and 100%, where higher percentages denote greater recruitment. introduced (non-native) plant species. Ecosystem function was converted into a percentile value that ranges between 0 and 100%, where higher values denote greater function. Survivorship The percentage of overstory vegetation cover remaining from 2013 to 2016 was used to characterize survivorship and was quantified using spherical densiometer data. Survivorship was calculated using the following equation: Sj = SDj (t) SDj (t−1) where for macroplot (j), S is survivorship, SD is the spherical densiometer value, (t) represents data from 2016, and (t-1) represents data from 2013. Survivorship was converted into a percentile value, where higher percentages denote less crown dieback. Percentages over 100% were possible if cover increased during this time period. ESj = Strataj Stratamax ESj = Strataj Stratamax where for each macroplot (j), ES is the ecosystem structure, Strata is the number of strata, and Stratamax is the maximum number of strata. In this case, Stratamax was seven based on the chosen protocol to characterize vegetation. Ecosystem structure was converted into a percentile value that ranges between 0 and 100%, where higher percentages denote greater vertical structure in the forest. Native Plant Dominance Native plant dominance was used as a health indicator because it can provide insight on whether the ecosystem’s function is intact. Ecosystem function is generally defined as an ecosystem’s ability to maintain multiple functions, such as carbon storage, nutrient cycling, and the transfer of energy via growth and decomposition. Functional responses to stress induced by changes in groundwater have been reported to cause changes in community composition such that native species are outcompeted by non-native species (Keddy and Reznicek, 1986; Moore and Keddy, 1988; Sommer and Froend, 2014). Numerous studies have also shown the ability of non-native invasive species to alter the flow of energy and cycling of materials within an ecosystem, and thus its functioning (Vitousek et al., 1987; D’Antonio, 1992; Vitousek, 1997; Gordon, 1998; Mack and D’Antonio, 1998; Cicchetti and Diaz, 2002; Meyerson et al., 2002; Ehrenfeld, 2003; Kourtev et al., 2003; Levine et al., 2003; Dukes and Mooney, 2004; USEPA, 2016). Although the presence of non- native invasive species may not necessarily alter the functioning of an ecosystem (Barney et al., 2013), the presence of native species can at a minimum be indicative that ecosystem function is more likely to be intact. In this study, we use native plant dominance as a rough proxy for ecosystem function, which was calculated by comparing the percent of native plant cover to total plant cover: Frontiers in Environmental Science | www.frontiersin.org Electrical Resistivity Tomography ect ca es st ty o og ap y The following subsections outline the ERT results from the Oneto-Denier area and each forest block (Castello, Shaw, and Tall). At the time of the survey no rainfall had been recorded in the area for 5+ months, leaving the water table at the bottom extents of the ERT images. Data acquisition was completed in <2 h per profile and temperatures remained constant throughout the survey. The study area is known to have low salinity. Therefore, ERT responses are interpreted as a function of soil texture and water content. Well logs indicate the lower resistivity values (20 m or less) to be associated with clay-dominated sediments, and higher resistivity values (40 m and greater) with sand-dominated sediments. Fj = NPj NPj + IPj where for macroplot (j), F is the ecosystem function, NP is the total cover of native plant species, and IP is the total cover of November 2019 | Volume 7 | Article 175 Frontiers in Environmental Science | www.frontiersin.org 7 Hydrological Controls on Groundwater-Dependent Ecosystem Health Rohde et al. Rohde et al. Hydrological Controls on Groundwater-Dependent Ecosystem Health FIGURE 4 | Long-term hydrologic time series. (A) Monthly precipitation (mm), and depth to groundwater in the unconfined aquifer (meters below ground surface) near (B) Castello forest, (C) Castello forest, and (D) Tall forest. The vertical red line denotes when ERT data collection occurred nearby. FIGURE 4 | Long-term hydrologic time series. (A) Monthly precipitation (mm), and depth to groundwater in the unconfined aquifer (meters below ground surface) near (B) Castello forest, (C) Castello forest, and (D) Tall forest. The vertical red line denotes when ERT data collection occurred nearby. Frontiers in Environmental Science | www.frontiersin.org Oneto-Denier sediments is expected to be the cause of this shallow high- resistive zone. The ERT results correlated well with local geologic maps1 and lithologic data from the MW5 well log (Figure 6B). At the time of ERT-P1 data acquisition, the groundwater table (pink triangle, Figure 6B) at MW5 was 11.6 m below ground and was obscured by the clay content of the local soil. ERT-P1 results (Figure 6) show some lateral and vertical soil heterogeneity. The MW5 lithologic log (Figure 6B) is dominated by silts and clays with some sand that result in low (cool colors) resistivity values throughout the profile, with the exception of a slightly more resistive zone at 6–12 m depth from 60 to 120 m along the profile, which we interpret is associated with sandier material below the more laterally extensive silt and clay observed in the lithologic log. Near the river bank at the beginning of ERT-P1 (0–50 m along the profile) we observed a shallow highresistivity zone that corresponds to coarser alluvial substrate that has been deposited in an eroded elevated part of the channel (like an over-flow channel) when stream flows exceed capacity. The deposition of these coarse The results for ERT-P2 (Figure 6C) show strong heterogeneity both laterally and vertically, where more resistive soils at 40– 60 m (depth of 6–10 m) and 100–130 m (depth of 6–12 m) indicate sandy soil zones that are consistent with the MW9 lithological log data. At the time of ERT-P2 data acquisition, the groundwater table at MW9 was 10.0 m below ground (pink triangle, Figure 6C) and again was obscured by the soil texture. November 2019 | Volume 7 | Article 175 Frontiers in Environmental Science | www.frontiersin.org 8 Hydrological Controls on Groundwater-Dependent Ecosystem Health Rohde et al. FIGURE 5 | Recent hydrologic time series. (A) Monthly precipitation (mm), and depth to groundwater in the unconfined aquifer (meters below ground surface) at (B) MW5 in Oneto-Denier, (C) MW9 in Oneto-Denier, and (D) MW2 in Shaw forest. The vertical red line denotes when ERT data collection occurred at each site. FIGURE 5 | Recent hydrologic time series. (A) Monthly precipitation (mm), and depth to groundwater in the unconfined aquifer (meters below ground surface) at (B) MW5 in Oneto-Denier, (C) MW9 in Oneto-Denier, and (D) MW2 in Shaw forest. The vertical red line denotes when ERT data collection occurred at each site. Oneto-Denier Both ERT-P1 and ERT-P2 exhibit a more resistive layer near the ground surface (<2 m depth), which likely corresponds to and is affected by the vegetative root zone. Differences in the duration of plant water uptake between ERT-P1 (dead winter annual grass) and ERT-P2 (live perennial grass) likely contributed to the more resistive topsoil in ERT-P2. documents indicates that in the mid-1800s, the Cosumnes River ran west of its current course, breaking into distributaries just south of present-day Shaw Forest and creating a mosaic of seasonal and perennial wetlands (Whipple et al., 2012). Frontiers in Environmental Science | www.frontiersin.org Castello Forest Overall, results from ERT-P2 and lithologic logs indicate the west side of the river at Oneto-Denier has slightly more sandy soils than ERT-P1 on the east side of the river. The observed differences in soil type at depth between ERT-P1 and ERT-P2 are supported by the geologic and land history record. The geologic map (how to cite?) shows the very clay-dominated Riverbank Formation underlying soils on the east side of the river at this latitude. Recent compilation and interpretation of historical Profiles ERT-P3 and ERT-P4 were collected at Castello Forest (Figure 7A) adjacent to macroplots (MP) MP-6 and MP-13, respectively. ERT-P3 was enclosed within the canopy of mature trees except for a gap at ∼70 m, and ERT-P4 was positioned across a boundary between mature canopy and a more open area dominated by annual grasses with few scattered shrubs. Both ERT-P3 and ERT-P4 (Figures 7B,C) show a more resistive subsurface with greater vertical heterogeneity than any of the November 2019 | Volume 7 | Article 175 9 Hydrological Controls on Groundwater-Dependent Ecosystem Health Rohde et al. Oneto-Denier (A) ERT study site, (B) ERT-P1 inversion results, and (C) ERT-P2 inversion results. ERT data were collected in October 2016 after significant cm). The water table at the time of data collection is denoted by the pink inverted triangle. FIGURE 6 | Oneto-Denier (A) ERT study site, (B) ERT-P1 inversion results, and (C) ERT-P2 inversion results. ERT data were collected in October 2016 after significant rainfall (∼5 cm). The water table at the time of data collection is denoted by the pink inverted triangle. FIGURE 6 | Oneto-Denier (A) ERT study site, (B) ERT-P1 inversion results, and (C) ERT-P2 inversion results. ERT data were collected in October 2016 after significant rainfall (∼5 cm). The water table at the time of data collection is denoted by the pink inverted triangle. other ERT profiles (see Figures 6B,C, 8B,C, 9B,C). In ERT-P3, a zone of higher resistivity in the near surface (∼2 m depth) extends along the entire profile except where it thins to ∼1 m depth around 70 m (red box, Figure 7B). This variation in the near-surface resistive zone is consistent with the greater water demands and water lifting capabilities of mature trees as compared to shallowly rooted grasses. Frontiers in Environmental Science | www.frontiersin.org Castello Forest Likewise, from 0 to 40 m in ERT-P4, the near-surface resistive zone is thinner than after the transition from the grass to the tree coverage (red box, Figure 7C), again showing a potential influence of plant life form (grass vs. tree) on soil moisture. Beyond 40 m in ERT-P4 within the tree coverage, the near-surface resistive zone extends even slightly deeper than observed in ERT- P3. Given the overall higher subsurface resistivity values at Castello Forest, along with the observed sandier surface soils and their similarity to the higher resistivity values in the sandy soil zones in ERT-P2 (MW9), these soils are interpreted as sandy. November 2019 | Volume 7 | Article 175 Frontiers in Environmental Science | www.frontiersin.org 10 Hydrological Controls on Groundwater-Dependent Ecosystem Health Rohde et al. FIGURE 7 | Castello Forest (A) ERT study site, (B) ERT inversion results for ERT-P3, and (C) ERT inversion results for ERT-P4. Red boxes denote sections along the ERT transect with less woody vegetation and resulting wetter soils (low resistivity) compared to remainder of the vegetated transect line. FIGURE 7 | Castello Forest (A) ERT study site, (B) ERT inversion results for ERT-P3, and (C) ERT inversion results for ERT-P4. Red boxes denote sections along the ERT transect with less woody vegetation and resulting wetter soils (low resistivity) compared to remainder of the vegetated transect line. FIGURE 7 | Castello Forest (A) ERT study site, (B) ERT inversion results for ERT-P3, and (C) ERT inversion results for ERT-P4. Red boxes denote sections along the ERT transect with less woody vegetation and resulting wetter soils (low resistivity) compared to remainder of the vegetated transect line. Shaw Forest resistivity that is interpreted as sandier soils (based on interpreted resistivity values at ERT-P2, ERT-P3, and ERT-P4). The near- surface soils (<2 m depth) are more resistive from 60 to 128 m along ERT-P5, which correlates to denser understory vegetation (red box, Figure 8B). A lower density of understory vegetation along the first half of ERT-P5 correlates with less resistive near-surface soils. The ERT-P6 profile correlates well with MW2 (Figure 8C) and the low-density understory vegetation matches with less resistive near-surface soils (<2 m depth). The Perpendicular profiles ERT-P5 and ERT-P6 were collected at Shaw Forest (Figure 8A) adjacent to MP-18 and MW-2, respectively. ERT-P5 results (Figure 8B) indicate silt/clay soils, much like those at ERT-P1 (Oneto-Denier), with both vertical and lateral soil heterogeneity. Nearby lithologic data from the MW-2 well log indicate pervasive silts and clays from 0 to 12 m depth. Resistivity values along ERT-P5 show agreement with this well log, except at 80 m where there is an isolated zone of low November 2019 | Volume 7 | Article 175 Frontiers in Environmental Science | www.frontiersin.org 11 Rohde et al. Hydrological Controls on Groundwater-Dependent Ecosystem Health aw forest (A) ERT study site, (B) ERT inversion results for ERT-P5, and (C) ERT inversion results for ERT-P6. Dashed yellow lines in (B,C) denote the nt between these two ERT profiles. The red box in (B) denotes the section of the ERT profile that is more vegetated by thick blackberry bushes, er resistivity. FIGURE 8 | Shaw forest (A) ERT study site, (B) ERT inversion results for ERT-P5, and (C) ERT inversion results for ERT-P6. Dashed yellow lines in (B,C) denote the intersection point between these two ERT profiles. The red box in (B) denotes the section of the ERT profile that is more vegetated by thick blackberry bushes, resulting in higher resistivity. FIGURE 8 | Shaw forest (A) ERT study site, (B) ERT inversion results for ERT-P5, and (C) ERT inversion results for ERT-P6. Dashed yellow lines in (B,C) denote the intersection point between these two ERT profiles. The red box in (B) denotes the section of the ERT profile that is more vegetated by thick blackberry bushes, resulting in higher resistivity vegetation along ERT-P6 and the beginning (0–60 m) of ERT-P5 comprised the same dominant plant species compared to the end of ERT-P5. with mild lateral and vertical heterogeneity. Shaw Forest Although there are no monitoring wells nor lithological logs in Tall Forest, ERT- P7 resistivity values were compared to the range of values in Shaw Forest and Oneto-Denier, where monitoring wells exist. The subsurface soils at ERT-P7 are interpreted as silt and clay deposits from 0 to 60 m along the profile. Conversely, beyond 60 m the soils show slightly higher resistivity, which based on results observed at ERT-P2 were interpreted as slightly sandier. Tall Forest One ERT profile (ERT-P7) was collected at Tall Forest (Figure 9) adjacent to a dirt access road just inside the edge of the forest due to the density of the forest undergrowth. ERT-P7 resistivity results (Figure 9B) show low resistivity conditions November 2019 | Volume 7 | Article 175 Frontiers in Environmental Science | www.frontiersin.org 12 Rohde et al. Hydrological Controls on Groundwater-Dependent Ecosystem Health FIGURE 9 | Tall Forest (A) ERT study site and (B) ERT inversion results for ERT-P7. Forest (A) ERT study site and (B) ERT inversion results for ERT-P7. FIGURE 9 | Tall Forest (A) ERT study site and (B) ERT inversion results for ERT-P7. FIGURE 9 | Tall Forest (A) ERT study site and (B) ERT inversion results for ERT-P7. DISCUSSION Vegetation Health Indicators November 2019 | Volume 7 | Article 175 Vegetation Health Indicators For each forest stand, summary statistics were calculated for: (1) the 2013 and 2016 vegetation survey data (Table 2) used to calculate each health indicator, and (2) the six health indicators for each forest (Table 3; Figure 10). Castello Forest was found to be statistically different (p < 0.05) from both Shaw Forest and Tall Forest for all six health indicators. Shaw Forest and Tall Forest were statistically similar (Table 3) for four of the health indicators (growth, diversity, structure, and survivorship), and statistically different (p < 0.05) for two of the health indicators (regeneration and native plant dominance). Castello Forest scored lower than both Shaw Forest and Tall Forest on every health indicator, and Tall Forest scored higher than Shaw Forest for the regeneration and native plant dominance indicators. Relative differences in health indicators between forests resulted in Castello Forest having the least healthy conditions due to lower growth, species diversity, regeneration, vertical structure, and survivorship of canopy from between 2013 and 2016. Health conditions of Tall and Shaw Forests were more similar to each other in comparison to Castello Forest, but slightly higher scores for regeneration and native plant dominance resulted in Tall Forest having the healthiest conditions. Lithological and Hydrological Conditions Subsurface lithological conditions in each forest were characterized using ERT and lithological logs from available monitoring wells. These independent data sources corroborated each other and indicated broad qualitative differences across the forest stands studied. Castello Forest showed sandier soils than Shaw and Tall Forests, which both showed high clay/silt content. Strong precedence exists to link soil texture as imaged by ERT with the hydrological factor of soil moisture. It is broadly accepted that clays and silts have much greater water retention capacity than sands. Development of the ERT method identified soil moisture as a separate factor influencing resistivity, and when present with clay, the two are highly correlated. These principles developed from empirical testing were applied in a similar study by Robinson et al. (2008), where soil electrical conductivity (inverse of resistivity) was used to map soil spatial distributions across a large landscape with diverse plant communities. After testing soil samples for clay content and volumetric water content, they found soil resistivity to be controlled by both factors, which were also positively correlated with each other and soil water retention. These results are very similar to findings Frontiers in Environmental Science | www.frontiersin.org Lithological and Hydrological Conditions n Mean SD Min Max Castello forest Total species count 19 14.1 2.5 11 18 Total # of native species 19 6.7 1.3 5 9 Total # of invasive species 19 7.3 1.9 4 11 Spherical Densiometer (2013) 19 66.1 25.9 18.2 98.7 Spherical Densiometer (2016) 19 35.0 14.7 12.2 59.1 Total cover of native plants 19 30.5 17.7 6.0 80.5 Total cover of introduced plants 19 95.0 19.8 17.0 114.5 Shannon-Wiener Evenness index 19 0.4 0.1 0.2 0.6 Total # of saplings 19 0.8 1.2 0 4 Total # of young trees 19 2.1 1.3 0 4 Total # of mature trees 19 1.7 1.1 0 4 Number of strata 19 3.6 1.4 2 6 Shaw forest Total species count 20 16.1 5.5 10 32 Total # of native species 20 9.8 3.0 5 18 Total # of invasive species 20 6.2 2.8 3 13 Spherical Densiometer (2013) 19 90.9 8.7 61.7 98.4 Spherical Densiometer (2016) 20 69.1 13.8 27.6 92.4 Total cover of native plants 20 90.5 39.2 32.0 182.0 Total cover of introduced plants 20 34.0 31.0 2.0 124.0 Shannon-Wiener Evenness index 20 0.6 0.1 0.3 0.7 Total # of saplings 20 12.1 10.7 0 43 Total # of young trees 20 5.8 3.2 0 15 Total # of mature trees 20 3.3 2.1 0 9 Number of strata 20 6.4 0.7 5 7 Tall forest Total species count 17 14.0 8.4 5 37 Total # of native species 17 10.8 5.3 5 24 Total # of invasive species 17 2.9 3.2 0 13 Spherical Densiometer (2013) 17 88.1 14.6 46.1 99.2 Spherical Densiometer (2016) 14 71.1 18.7 22.9 93.2 Total cover of native plants 17 117.6 35.7 64.5 170.5 Total cover of introduced plants 17 4.8 8.8 0.0 35.5 Shannon-Wiener Evenness index 17 0.6 0.1 0.5 0.8 Total # of saplings 17 35.5 22.6 2 78 Total # of young trees 17 9.2 4.9 1 20 Total # of mature trees 17 3.6 2.8 0 10 Number of strata 17 5.9 0.9 4 7 All forests Total species count 56 14.8 5.8 5 37 Total # of native species 56 9.1 3.8 5 24 Total # of invasive species 56 5.6 3.2 0 13 Spherical Densiometer (2013) 55 81.4 21.0 18.2 99.2 Spherical Densiometer (2016) 53 57.4 22.8 12.2 93.2 Total cover of native plants 56 78.4 48.2 6.0 182.0 Total cover of introduced plants 56 45.8 43.5 0.0 124.0 Shannon-Wiener Evenness index 56 0.5 0.1 0.2 0.8 Total # of saplings 56 15.4 19.8 0 78 Total # of young trees 56 5.6 4.4 0 20 Total # of mature trees 56 2.9 2.2 0 10 Number of strata 56 5 3 1 6 2 7 TABLE 2 | Summary statistics for vegetation data included in analyses. Lithological and Hydrological Conditions g y g Subsurface lithological conditions in each forest were characterized using ERT and lithological logs from available monitoring wells. These independent data sources corroborated each other and indicated broad qualitative differences across the forest stands studied. Castello Forest showed sandier soils than Shaw and Tall Forests, which both showed high clay/silt content. Strong precedence exists to link soil texture as imaged by ERT with the hydrological factor of soil moisture. It is broadly accepted that clays and silts have much greater water retention capacity than sands. Development of the ERT method identified soil moisture as a separate factor influencing resistivity, and when present with clay, the two are highly correlated. These principles developed from empirical testing were applied in a similar study by Robinson et al. (2008), where soil electrical conductivity (inverse of resistivity) was used to map soil spatial distributions across a large landscape with diverse plant communities. After testing soil samples for clay content and volumetric water content, they found soil resistivity to be controlled by both factors, which were also positively correlated with each other and soil water retention. These results are very similar to findings November 2019 | Volume 7 | Article 175 Frontiers in Environmental Science | www.frontiersin.org 13 Hydrological Controls on Groundwater-Dependent Ecosystem Health Rohde et al. TABLE 2 | Summary statistics for vegetation data included in analyses. Lithological and Hydrological Conditions from this study, where low resistivity values were associated with soils of high clay content as observed in well logs. We therefore adopt the fundamental concept that water retention was higher in our clay-rich soils compared to the sandier soils. Hydrologic evidence from the lower Cosumnes study system also strongly supports the connection between ERT measurements and soil moisture. Figures 4, 5 show that the predominance of silt and clay that was observed in Tall Forest was also coincident with the shallowest groundwater levels observed through the historical record over nearly 50 years (Figure 4C), with groundwater levels ranging between 0.5 and 3.7 m. In contrast, Castello forest had predominantly sandy soils and the deepest groundwater levels observed (5.1–25.2 m; Figures 4A,B). Four years of data over a prolonged drought show that Shaw Forest had groundwater levels intermediate between these two (4.2–13.5 m; Figure 5C). Therefore, groundwater availability (higher soil moisture content and shallower groundwater levels) increased progressively downstream from Castello Forest to Shaw Forest to Tall Forest. Increasing groundwater availability along the Cosumnes River is likely a combination of groundwater flow gradients and soil type differences between forests. The spatial distribution of riparian forests along this groundwater gradient provides an opportunity to observe which groundwater levels are supportive of healthy conditions within a GDE. GDE Health In this study, we developed an approach to quantify ecosystem health within GDEs, using metrics of groundwater-dependent vegetation as indicators, so that health conditions could be statistically compared across the landscape. Vegetation indicators used to infer GDE health conditions demonstrated that Shaw and Tall Forests have statistically similar and greater health conditions than Castello Forest. One of the major biological differences between the forests was that Shaw and Tall Forests both had a lush understory, whereas Castello Forest did not. This difference was captured in the vegetative growth, regeneration, and structure indicators, such that both Shaw and Tall Forests exhibited higher vegetative growth (canopy cover), regeneration (sapling recruitment), and structure (number of strata present, including young trees) than Castello Forest. A lack of regeneration at Castello Forest indicates that health conditions may be in an unsustainable state in comparison to Shaw and Tall Forests. Greater vertical structure at Tall and Shaw Forests compared to Castello Forest was also correlated to the diversity and native plant dominance indicators. Greater species diversity in Tall and Shaw Forests in comparison to Castello Forest was also accompanied by a greater proportion of native plant cover. These observations are consistent with previous research studies, which found changes in groundwater availability to cause a functional shift in the ecosystem away from native habitat toward more favorable conditions for invasive species (Keddy and Reznicek, 1986; Moore and Keddy, 1988; Sommer and Froend, 2014). Frontiers in Environmental Science | www.frontiersin.org Hydrological Controls on GDE Health y g On the larger scale of the river reach studied, comparisons among ERT profiles and groundwater monitoring well data showed November 2019 | Volume 7 | Article 175 Frontiers in Environmental Science | www.frontiersin.org 14 Hydrological Controls on Groundwater-Dependent Ecosystem Health Rohde et al. TABLE 3 | Statistical results for each ecological health indicator. Growth Diversity Regeneration Ecosystem structure Native plant dominance Survivorship Castello n 19 19 18 19 19 19 Mean 35.0 0.4 20.2 51.9 24.4 56.8 SD 14.7 0.1 32.5 19.8 15.2 19.3 Min 12.2 0.2 0 28.6 6.4 14.1 Max 59.1 0.6 100 85.7 74.4 86.9 Shaw n 20 20 20 20 20 19 Mean 69.1 0.6 50.5 91.4 73.1 77.4 SD 13.8 0.1 24.2 9.7 20.5 14 Min 27.6 0.3 0 71.4 32.8 32.5 Max 92.4 0.7 100 100 98.4 101.7 Tall n 17 17 17 17 17 15 Mean 73.8 0.6 68.6 84.9 96.7 80.5 SD 18.0 0.1 16.9 12.8 5.3 18.6 Min 22.9 0.5 18.2 57.1 79.2 30.4 Max 93.2 0.8 95.8 100 100 113.4 ANOVA (Herberich et al., 2010) Castello: shaw p < 0.05 p < 0.05 p < 0.05 p < 0.05 p < 0.05 p < 0.05 Castello: tall p < 0.05 p < 0.05 p < 0.05 p < 0.05 p < 0.05 p < 0.05 Shaw: tall p = 0.68 p = 0.26 p < 0.05 p = 0.22 p < 0.05 p = 0.87 TABLE 3 | Statistical results for each ecological health indicator. that clay-dominated sites (Shaw and Tall Forests) had shallower depth to groundwater, retained more soil moisture, and sustained healthier vegetation than the sandier site (Castello Forest), with its greater depth to groundwater, reduced soil moisture, and less healthy vegetation. This shows the strong influence of groundwater availability and soil type on groundwater- dependent riparian vegetation. Further studies may elucidate more detailed mechanisms shaping groundwater availability, such as hydraulic effects of root networks and surface flood regimes. Further work may also refine the spatial scale at which within-forest differences could be affected by small-scale variations in underlying sediments. Our study, however, operated at the scale of entire forest stands underlain by a sequence of substantially different groundwater and soil conditions that together influenced subsurface water retention and availability of that water to a broad suite of plant species. Hydrological Controls on GDE Health can range in severity from declines in productivity to increased mortality (Scott et al., 1999; Shafroth et al., 2000; Canham et al., 2012, 2015). Even in cases where some individual groundwater- dependent plants have the capacity to adapt to gradual increases in water stress due to groundwater decline, changes in the ecosystem structure and community composition can still result (Froend and Sommer, 2010). This phenomenon is consistent with the decrease in number of strata and greater presence of non-native species in Castello Forest in contrast to Shaw and Tall Forests, thereby suggesting that long-term trends in groundwater conditions may be contributing to the poorer health conditions observed in Castello Forest. The absence of understory trees at Castello Forest sends a strong biological signal that regeneration is lacking and that the current groundwater regime may not be accessible to younger plants with shallower root systems. This is problematic because if the groundwater regime is not restored to conditions where sapling recruitment can occur, there will be no younger trees present to replace mature trees once they inevitably reach mortality. Groundwater depths near Castello Forest were also deeper than the water depth value of ∼10 m that is often used to indicate the likelihood that plant rooting depths are capable of accessing groundwater (Canadell et al., 1996; Eamus et al., 2015; Rohde et al., 2018). Routine monitoring of health indicators within each of the forest blocks, in conjunction with groundwater level data from monitoring wells over time, would help identify the groundwater level thresholds necessary to enable regeneration and support GDE health in this area. However, healthy conditions in Shaw Forest provide a preliminary insight into what groundwater levels (observed at MW2) may be necessary to support nearby riparian forests. With only 5 years of groundwater level data available at MW2, continuous monitoring of groundwater levels and biological responses over Therefore, differences in groundwater availability are most likely the cause for the observed differences in ecosystem health at our study sites, due to the spatial differences in groundwater availability influenced by soil type and the groundwater level gradient along the Cosumnes River. Our results support our hypothesis that differences in ecosystem health correlate to hydrological conditions, such that access to greater subsurface moisture from shallower groundwater levels results in the healthier conditions that were observed in Shaw and Tall Forests in comparison to Castello Forest. Frontiers in Environmental Science | www.frontiersin.org Hydrological Controls on GDE Health Some groundwater-dependent plants may have the adaptive capacity to cope with absolute and relative changes to groundwater availability depending on the rate, magnitude, and duration of groundwater changes. However, previous research demonstrates that if absolute and relative groundwater changes are too drastic for rooting networks to adapt, groundwater changes can result in a spectrum of biological responses, which November 2019 | Volume 7 | Article 175 15 Hydrological Controls on Groundwater-Dependent Ecosystem Health Rohde et al. FIGURE 10 | Box plots for each vegetation health indicator by forest stand. Dots represent data points outside the 25th and 75th percentiles (represented as the vertical, thin black line). FIGURE 10 | Box plots for each vegetation health indicator by forest stand. Dots represent data points outside the 25th and 75th percentiles (represented as the vertical, thin black line). vegetation health indicator by forest stand. Dots represent data points outside the 25th and 75th percentiles (represented as the FIGURE 10 | Box plots for each vegetation health indicator by forest stand. Dots represent data points outside the 25th and 75th vertical, thin black line). time would help elucidate cause-and-effect relationships between groundwater and the riparian forest, so adaptive management can occur as more information becomes available. approach for deducing the subsurface structure and soil moisture distribution within ecosystems. Transdisciplinary approaches such as these can elucidate insights on how these systems functionally respond to changes or spatial differences in groundwater availability. Frontiers in Environmental Science | www.frontiersin.org November 2019 | Volume 7 | Article 175 CONCLUSION This study also demonstrated the value of using vegetation survey data to deduce GDE health. Vegetation survey data offers the ability to determine a wide variety of biological responses in an ecosystem ranging from growth to survivorship, which can be used to investigate groundwater impacts to ecosystems. It is highly advised that groundwater sustainability managers interpret biological information in conjunction with hydrologic data so that only those changes to ecosystem health due to groundwater are addressed (Rohde et al., 2018). It is important to note that although using vegetation data to deduce ecosystem health is best used as a surveillance indicator in routine monitoring, that it may overlook some critical biological responses of rare, threatened, and endangered species. In these circumstances, it is highly advised that water managers consider This transdisciplinary study exemplifies the utility of combining geophysical, geological, hydrological, and biological data to explore potential groundwater impacts on GDEs in an unconfined aquifer system. Hydrologic data gaps in interconnected surface water systems are common due to heterogeneous subsurface conditions, but are important to understand since the interconnections between surface water and groundwater can support perched groundwater, which can offer an accessible source of groundwater to riparian vegetation when unconfined aquifers are too deep. While it may be difficult to accurately represent subsurface conditions in these aquifer settings using sparse monitoring well networks and numerical groundwater models, geophysics offers a complementary November 2019 | Volume 7 | Article 175 Frontiers in Environmental Science | www.frontiersin.org 16 Hydrological Controls on Groundwater-Dependent Ecosystem Health Rohde et al. additional biological investigations that can better characterize the condition of these valuable environmental assets. led collection and management of the vegetation survey data, assisted with the ERT data collection, helped in all aspects of the research especially those pertaining to the vegetation data, and assisted with the writing of the manuscript. CU collected and analyzed all of the ERT data, and assisted in writing of the manuscript. JH assisted in the analysis and writing. Successful implementation of sustainable groundwater legislation relies on practical biological and hydrologic metrics that can be incorporated into monitoring regimes. For practical reasons, monitoring regimes should at a minimum provide some basic surveillance of the hydrologic conditions supporting GDEs and the biological conditions within the GDE, so that cause- and-effect relationships can be deduced. REFERENCES orchard in Trentino, North-Eastern Italy. Sci. Total Environ. 543, 851–861. doi: 10.1016/j.scitotenv.2015.03.113 orchard in Trentino, North-Eastern Italy. Sci. Total Environ. 543, 851–861. doi: 10.1016/j.scitotenv.2015.03.113 Barney, J. N., Tekiela, D. R., Dollete, E. S., and Tomasek, B. J. (2013). What is the “real” impact of invasive plant species? Front. Ecol. Environ. 11, 322–329. doi: 10.1890/120120 CDFW (1988). A Guide to Wildlife Habitats of California. Available online CDFW (1988). A Guide to Wildlife Habitats of California. Available online at: https://www.wildlife.ca.gov/Data/CWHR/Wildlife-Habitats (accessed December 12, 2018). at: https://www.wildlife.ca.gov/Data/CWHR/Wildlife-Habitats (accessed December 12, 2018). Bernhardt, E. A., and Swiecki, T. J. (1991). Guidelines for Developing and Evaluating Tree Ordinances. Available online at: http://www.isa-arbor.com/education/ resources/educ_treeordinanceguidelines.pdf (accessed March 16, 2017). Chapin, F. S. III (1997). Biotic control over the functioning of ecosystems. Science 277, 500–504. doi: 10.1126/science.277.5325.500 Cicchetti, G., and Diaz, R. J. (2002). “Types of salt marsh edge and export of trophic energy from marshes to deeper habitats,” in Concepts and Controversies in Tidal Marsh Ecology, eds M. P. Weinstein and D. A. Kreeger (Dordrecht: Kluwer Academic Publishers), 515–541. Binley, A., and Kemna, A. (2005). “DC resistivity and induced polarization methods,” in Hydrogeophysics, eds Y. Rubin and S. S. Hubbard (Dordrecht: Springer), 129–156. Blevins, E., and Aldous, A. (2011). Biodiversity Value of Groundwater-Dependent Ecosystems. Portland, OR: Wetland Science & Practice, 18–24. Available online at: https://www.conservationgateway.org/ConservationByGeography/ NorthAmerica/UnitedStates/oregon/freshwater/Documents/GW_Blevins %20and%20Aldous_2011_WSP.pdf (accessed October 28, 2019). Costanza, R., and Mageau, M. (1999). What is a healthy ecosystem? Aquatic Ecol. 33, 105–115. doi: 10.1023/A:10099303 13242 %20and%20Aldous_2011_WSP.pdf (accessed October 28, 2019). Daily, W., Ramirez, A., LaBrecque, D., and Nitao, J. (2010). Electrical resistivity tomography of vadose water movement. Water Resour. Res. 28, 1429–1442. doi: 10.1029/91WR03087 Canadell, J., Jackson, R. B., Ehleringer, J. B., Mooney, H. A., Sala, O. E., and Schulze, E. D. (1996). Maximum rooting depth of vegetation types at the global scale. Oecologia 108, 583–595. doi: 10.1007/BF00329030 D’Antonio, C. (1992). Biological invasions by exotic grasses, the grass fire cycle, and global change. Annu. Rev. Ecol. Syst. 23, 63–87. doi: 10.1146/annurev.es.23.110192.000431 Canham, C. A., Froend, R. H., and Stock, W. D. (2015). Rapid root elongation by phreatophyte seedlings does not imply tolerance of water table decline. Trees 29, 815–824. doi: 10.1007/s00468-015-1161-z Davies, S. P., and Jackson, S. K. (2006). The biological condition gradient: a descriptive model for interpreting change in aquatic ecosystems. Ecol. Appl. 16, 1–16. doi: 10.1890/1051-0761(2006)016[1251:TBCGAD] 2.0.CO;2 Canham, C. A., Froend, R. H., Stock, W. D., and Davies, M. (2012). ACKNOWLEDGMENTS The authors would like to thank The Nature Conservancy’s seasonal staff(Audrey Kelly, Victor Oelschlaegel, Troy Shea, and Jane Thompson) for their help in the field with vegetation monitoring and geophysical data collection. We also would like to thank Jesse Roseman for inspiring this research work in the Cosumnes River Preserve. We also thank Dr. Graham Fogg, Stephen Maples, and Alysa (Amy) Yoder at the University of California, Davis for providing monitoring well data within the Cosumnes River Preserve. We also thank Dr. Baptiste Dafflon and Dr. Emmanuel Leger for their help interpreting ERT data by integrating the BERT inversion code using Matlab routines. AUTHOR CONTRIBUTIONS MR was the lead researcher, developed the ecosystem health indicators, analyzed the results, and drafted the manuscript. SS CONCLUSION Practical biological indicators that can integrate ecosystem-scale biological data into water management monitoring programs and be used to assess the health of GDEs in relation to hydrological conditions are necessary but often missing in groundwater management and monitoring programs. This study provides an approach for water managers to integrate practical biological indicators that can characterize GDE health into monitoring programs, so that groundwater thresholds can be locally determined and adverse impacts to ecosystems can be avoided. By monitoring GDE health over time, water practitioners can determine if a correlation exists between GDE health metrics and hydrologic datasets that signal that potential groundwater impacts to the ecosystem are occurring. This would help water managers identify groundwater thresholds that can sustain GDEs and prioritize limited funds and management efforts so that adaptive management of GDEs under sustainable groundwater management can ensue. FUNDING We would like to thank the S. D. Bechtel, Jr. Foundation for their philanthropic financial support to The Nature Conservancy’s ongoing groundwater research on GDEs in sustainable groundwater management. We would like to thank the S. D. Bechtel, Jr. Foundation for their philanthropic financial support to The Nature Conservancy’s ongoing groundwater research on GDEs in sustainable groundwater management. We would like to thank the S. D. Bechtel, Jr. Foundation for their philanthropic financial support to The Nature Conservancy’s ongoing groundwater research on GDEs in sustainable groundwater management. REFERENCES Dynamics of phreatophyte root growth relative to a seasonally fluctuating water table in a mediterranean-type environment. Oecologia 170, 909–916. doi: 10.1007/s00442-012-2381-1 Dukes, J. S., and Mooney, H. A. (2004). Disruption of ecosystem processes in western North America by invasive species. Rev. Chil. Hist. Nat. 77, 411–437. doi: 10.4067/S0716-078X2004000300003 Cassiani, G., Boaga, J., Rossi, M., Putti, M., Fadda, G., Majone, B., et al. (2016). Soil–plant interaction monitoring: small scale example of an apple November 2019 | Volume 7 | Article 175 Frontiers in Environmental Science | www.frontiersin.org 17 Hydrological Controls on Groundwater-Dependent Ecosystem Health Rohde et al. Eamus, D., Froend, R., Loomes, R., Hose, G., and Murray, B. (2006a). A functional methodology for determining the groundwater regime needed to maintain the health of groundwater-dependent vegetation. Aust. J. Bot. 54:97. doi: 10.1071/BT05031 Meyerson, L. A., Vogt, K. A., and Chambers, R. M. (2002). “Linking the success of phragmites to the alteration of ecosystem nutrient cycles,” in Concepts and Controversies in Tidal Marsh Ecology, eds M. P. Weinstein and D. A. Kreeger (Dordrecht: Kluwer Academic Publishers), 827–844. Eamus, D., Hatton, T., Cook, P., and Colvin, C. (2006b). Ecohydrology: Vegetation Function, Water and Resource Management. Collingwood, VIC: CSIRO Publishing. Moore, D. R. J., and Keddy, P. A. (1988). Effects of a water-depth gradient on the germination of lakeshore plants. Can. J. Bot. 66, 548–552. doi: 10.1139/ b88-078 Nijland, W., van der Meijde, M., Addink, E. A., and de Jong, S. M. (2010). Detection of soil moisture and vegetation water abstraction in a Mediterranean natural area using electrical resistivity tomography. CATENA 81, 209–216. doi: 10.1016/j.catena.2010.03.005 Eamus, D., Zolfaghar, S., Villalobos-Vega, R., Cleverly, J., and Huete, A. (2015). Groundwater-dependent ecosystems: recent insights from satellite and field-based studies. Hydrol. Earth Syst. Sci. 19, 4229–4256. doi: 10.5194/hess-19-4229-2015 Ehrenfeld, J. G. (2003). Effects of exotic plant invasions on soil nutrient cycling processes. Ecosystems 6, 503–523. doi: 10.1007/s10021-002-0151-3 Niswonger, R. G., and Fogg, G. E. (2008). Influence of perched groundwater on base flow. Water Resour. Res. 44:602. doi: 10.1029/2007WR0 06160 Fleckenstein, J. H., Niswonger, R. G., and Fogg, G. E. (2006). River-aquifer interactions, geologic heterogeneity, and low-flow management. Ground Water 44, 837–852. doi: 10.1111/j.1745-6584.2006.00190.x Palkovics, W. E., Petersen, G. W., and Matelski, R. P. (1975). Perched water table fluctuation compared to streamflow1. Soil Sci. Soc. Am. J. 39:343. doi: 10.2136/sssaj1975.03615995003900020030x Froend, R., and Sommer, B. (2010). REFERENCES Phreatophytic vegetation response to climatic and abstraction-induced groundwater drawdown: examples of long- term spatial and temporal variability in community response. Ecol. Eng. 36, 1191–1200. doi: 10.1016/j.ecoleng.2009.11.029 Pearson, D. L. (1971). Vertical stratification of birds in a tropical dry forest. Condor 73, 46–55. doi: 10.2307/1366123 R Development Core Team (2008). R: A Language and Environment for Statistical Computing. Available online at: http://www.R-project.org (accessed September 7, 2017). Gleeson, T., Befus, K. M., Jasechko, S., Luijendijk, E., and Cardenas, M. B. (2015). The global volume and distribution of modern groundwater. Nat. Geosci. 9, 161–167. doi: 10.1038/ngeo2590 Rassam, D. W., Fellows, C. S., De Hayr, R., Hunter, H., and Bloesch, P. (2006). The hydrology of riparian buffer zones; two case studies in an ephemeral and a perennial stream. J. Hydrol. 325, 308–324. doi: 10.1016/j.jhydrol.2005.10.023 Gordon, D. R. (1998). Effects of invasive, non-indigenous plant species on ecosystem processes: lessons from Florida. Ecol. Appl. 8, 975–989. doi: 10.1890/ 1051-0761(1998)008[0975:EOINIP]2.0.CO;2 Reynolds, J. M. (2011). An Introduction to Applied and Environmental Geophysics (Chichester: John Wiley & Sons, Ltd). Grelle, C. E. V. (2003). Forest structure and vertical stratification of small mammals in a secondary atlantic forest, Southeastern Brazil. Stud. Neotrop. Fauna Environ. 38, 81–85. doi: 10.1076/snfe.38.2.81.15926 Rhoades, J. D., Raats, P. A. C., and Prather, R. J. (1976). Effects of liquid- phase electrical conductivity, water content, and surface conductivity on bulk soil electrical conductivity1. Soil Sci. Soc. Am. J. 40:651. doi: 10.2136/sssaj1976.03615995004000050017x Gunther, T., and Rucker, C. (2006). “A new joint inversion approach applied to the combined tomography of DC resistivity and seismic refraction data,” in Society of Exploration Geophysicists, 1196–1202. Robinson, D. A., Campbell, C. S., Hopmans, J. W., Hornbuckle, B. K., Jones, S. B., Knight, R., et al. (2008). Soil moisture measurement for ecological and hydrological watershed-scale observatories: a review. Vadose Zone J. 7:358. doi: 10.2136/vzj2007.0143 Herberich, E., Sikorski, J., and Hothorn, T. (2010). A robust procedure for comparing multiple means under heteroscedasticity in unbalanced designs. PLoS ONE 5:e9788. doi: 10.1371/journal.pone.0009788 Robinson, J. L., Slater, L. D., and Schäfer, K. V. R. (2012). Evidence for spatial variability in hydraulic redistribution within an oak–pine forest from resistivity imaging. J. Hydrol. 430–431, 69–79. doi: 10.1016/j.jhydrol.2012. 02.002 Hothorn, T., Bretz, F., Westfall, P., Heiberger, R. M., Schuetzenmeister, A., and Scheibe, S. (2017). multcomp: Simultatenous Interference in General Parametric Models. Available online at: https://cran.r-project.org/web/ packages/multcomp/multcomp.pdf (accessed July 12, 2018). Rohde, M. M., Froend, R., and Howard, J. (2017). REFERENCES A global synthesis of managing groundwater dependent ecosystems under sustainable groundwater policy. Groundwater 55, 293–301. doi: 10.1111/gwat.12511 Hübner, R., Heller, K., Günther, T., and Kleber, A. (2015). Monitoring hillslope moisture dynamics with surface ERT for enhancing spatial significance of hydrometric point measurements. Hydrol. Earth Syst. Sci. 19, 225–240. doi: 10.5194/hess-19-225-2015 Rohde, M. M., Matsumoto, S., Howard, J. K., Liu, S., Riege, L., and Remson, E. J. (2018). Groundwater Dependent Ecosystems Under The Sustainable Groundwater Management Act: Guidance for Preparing Groundwater Sustainability Plans. San Francisco, CA: The Nature Conservancy. Kean, W. F., Waller, M. J., and Layson, H. R. (1987). Monitoring moisture migration in the vadose zone with resistivity. Ground Water 25, 562–571. doi: 10.1111/j.1745-6584.1987.tb02886.x Keddy, P. A., and Reznicek, A. A. (1986). Great lakes vegetation dynamics: the role of fluctuating water levels and buried seeds. J. Great Lakes Res. 12, 25–36. doi: 10.1016/S0380-1330(86)71697-3 Rutten, G., Ensslin, A., Hemp, A., and Fischer, M. (2015). Vertical and horizontal vegetation structure across natural and modified habitat types at mount kilimanjaro. PLoS ONE 10:e0138822. doi: 10.1371/journal.pone. 0138822 Klausmeyer, K. R., Howard, J. K., Keeler-Wolf, T., Davis-Fadtke, K., Hull, R., and Lyons, A. (2018). Mapping Indicators of Groundwater Dependent Ecosystems in California: Methods Report. San Francisco, CA: The Nature Conservancy. Samouëlian, A., Cousin, I., Tabbagh, A., Bruand, A., and Richard, G. (2005). Electrical resistivity survey in soil science: a review. Soil Tillage Res. 83, 173–193. doi: 10.1016/j.still.2004.10.004 Kleinschmidt Group, Inc. (2008). Cosumnes River Preserve Management Plan. Sacramento, CA: Privately Published. Available online at: http://cosumnes.org/ documents/managementplan.pdf (accessed October 28, 2019). Schulze, C. H., Linsenmair, K. E., and Fiedler, K. (2001). Plant Ecol. 153, 133–152. doi: 10.1023/A:1017589711553 Kourtev, P. S., Ehrenfeld, J. G., and Häggblom, M. (2003). Experimental analysis of the effect of exotic and native plant species on the structure and function of soil microbial communities. Soil Biol. Biochem. 35, 895–905. doi: 10.1016/S0038-0717(03)00120-2 Schuyt, K., and Brander, L. (2004). The Economic Value of the World’s Wetlands. Living Waters - Conserving the Source of Life, 1–32. Available online at: https:// www.researchgate.net/publication/288267725_The_economic_values_of_the_ world’s_wetlands (accessed October 28, 2019). Levine, J. M., Vila, M., Antonio, C. M. D., Dukes, J. S., Grigulis, K., and Lavorel, S. (2003). Mechanisms underlying the impacts of exotic plant invasions. Proc. R. Soc. B Biol. Sci. 270, 775–781. doi: 10.1098/rspb.2003.2327 Schwartz, B. F., Schreiber, M. E., and Yan, T. (2008). Quantifying field-scale soil moisture using electrical resistivity imaging. J. Hydrol. 362, 234–246. REFERENCES doi: 10.1016/j.jhydrol.2008.08.027 j j y Scott, M., Shafroth, P., and Auble, G. (1999). Responses of riparian cottonwoods to alluvial water table declines. Environ. Manage. 23, 347–358. doi: 10.1007/s002679900191 Ma, Y., Van Dam, R. L., and Jayawickreme, D. H. (2014). Soil moisture variability in a temperate deciduous forest: insights from electrical resistivity and throughfall data. Environ. Earth Sci. 72, 1367–1381. doi: 10.1007/s12665-014-3362-y Mack, M. C., and D’Antonio, C. M. (1998). Impacts of biological invasions on disturbance regimes. Trends Ecol. Evol. 13, 195–198. doi: 10.1016/S0169-5347(97)01286-X Shafroth, P. B., Stromberg, J. C., and Patten, D. T. (2000). Woody riparian vegetation response to different alluvial water table regimes. West. North Am. Nat. 60, 66–76. November 2019 | Volume 7 | Article 175 Frontiers in Environmental Science | www.frontiersin.org 18 Hydrological Controls on Groundwater-Dependent Ecosystem Health Rohde et al. Wada, Y., van Beek, L. P. H., and Bierkens, M. F. P. (2012). Nonsustainable groundwater sustaining irrigation: a global assessment. Water Resour. Res. 48:219. doi: 10.1029/2011WR010562 Sommer, B., and Froend, R. (2014). Phreatophytic vegetation responses to groundwater depth in a drying mediterranean-type landscape. J. Veg. Sci. 25, 1045–1055. doi: 10.1111/jvs.12178 Water Land and Ecosystems (WLE) and CRPO (2015). Groundwater and Ecosystem Services: A Framework for Managing Smallholder Groundwater- Dependent Agrarian Socio-Ecologies - Applying an Ecosystem Services and Resilience Approach. International Water Management Institute (IWMI); CGIAR Research Program on Water Land and Ecosystems (WLE). Strickler, G. S. (1959). Use of the Densiometer to Estimate Density of Forest Canopy on Permanent Sample Plots. Research Note - Number 180. Portland, OR: U. S. Department of Agriculture. Sudha, K., Israil, M., Mittal, S., and Rai, J. (2009). Soil characterization using electrical resistivity tomography and geotechnical investigations. J. Appl. Geophys. 67, 74–79. doi: 10.1016/j.jappgeo.2008. 09.012 Whipple, A. A., Grossinger, R. M., Rankin, D., and Stanford, B. (2012). Sacramento-San Joaquin Delta Historical Ecology Investigation: Exploring Pattern and Process. Richmond, VA: San Francisco Estuary Institute; Aquatic Science Center. Tabbagh, A., Dabas, M., Hesse, A., and Panissod, C. (2000). Soil resistivity: a non-invasive tool to map soil structure horizonation. Geoderma 97, 393–404. doi: 10.1016/S0016-7061(00)00047-1 Conflict of Interest: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. USEPA (2016). A Practitioner’s Guide to the Biological Condition Gradient: A Framework to Describe Incremental Change in Aquatic Ecosystems. EPA-842-R-16-001. Washington, DC: U.S.Environmental Protection Agency. Vitousek, P. M. (1997). Frontiers in Environmental Science | www.frontiersin.org November 2019 | Volume 7 | Article 175 REFERENCES Human domination of earth’s ecosystems. Science 277, 494–499. doi: 10.1126/science.277.5 325.494 Copyright © 2019 Rohde, Sweet, Ulrich and Howard. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Vitousek, P. M., Walker, L. R., Whiteaker, L. D., Mueller-Dombois, D., and Matson, P. A. (1987). Biological invasion by myrica faya alters ecosystem development in Hawaii. Science 238, 802–804. doi: 10.1126/science.238. 4828.802 November 2019 | Volume 7 | Article 175 Frontiers in Environmental Science | www.frontiersin.org 19
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Association between executive function and excess weight in pre-school children
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PLOS ONE RESEARCH ARTICLE Narueporn LikhitweerawongID1, Jiraporn Khorana2,3,4, Nonglak Boonchooduang1, Phichayut Phinyo3,5, Jayanton Patumanond3, Orawan Louthrenoo1* 1 Department of Pediatrics, Division of Growth and Development, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand, 2 Department of Surgery, Division of Pediatric Surgery, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand, 3 Center of Clinical Epidemiology and Clinical Statistic, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand, 4 Department of Surgery, Clinical Surgical Research Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand, 5 Department of Family Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 * orawan.l@cmu.ac.th * orawan.l@cmu.ac.th Editor: Hae Sang Lee, Ajou University School of Medicine, REPUBLIC OF KOREA Copyright: © 2022 Likhitweerawong et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: The data and code used to generate plots and perform statistical analyses have been uploaded to the Open Science Framework archive: https://osf.io/jdq6z/?view_ only=b2081b6607804ab8b95ada2ae27ba6d4. Association between executive function and excess weight in pre-school children Narueporn LikhitweerawongID1, Jiraporn Khorana2,3,4, Nonglak Boonchooduang1, Phichayut Phinyo3,5, Jayanton Patumanond3, Orawan Louthrenoo1* OPEN ACCESS Citation: Likhitweerawong N, Khorana J, Boonchooduang N, Phinyo P, Patumanond J, Louthrenoo O (2022) Association between executive function and excess weight in pre-school children. PLoS ONE 17(10): e0275711. https://doi. org/10.1371/journal.pone.0275711 Editor: Hae Sang Lee, Ajou University School of Medicine, REPUBLIC OF KOREA Received: May 10, 2022 Accepted: September 20, 2022 Published: October 10, 2022 Copyright: © 2022 Likhitweerawong et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Editor: Hae Sang Lee, Ajou University School of Medicine, REPUBLIC OF KOREA Received: May 10, 2022 Accepted: September 20, 2022 Published: October 10, 2022 Editor: Hae Sang Lee, Ajou University School of Medicine, REPUBLIC OF KOREA PLOS ONE PLOS ONE Abstract The association between executive function and excess weight is becoming increasingly evident. However, the results of previous studies are still inconclusive, and there is a lack of evidence in early childhood. This study aims to examine the association between executive function, in terms of overall and subscales of executive function (e.g., inhibition, working memory, and shifting), and weight excess in preschoolers. A population-based cross-sec- tional study was conducted on children aged 2–5 years of age from public and private schools in Chiang Mai, Thailand. Participants’ weights and heights were measured and clas- sified into three weight status groups (i.e., children with normal weight, overweight, and obe- sity groups). Executive function was assessed using the parent-report Behavior Rating Inventory of Executive Function-Preschool (BRIEF-P). Multivariable polynomial regression was performed to analyze the association between executive function and weight status. A total of 1,181 children were included in the study. After adjusting for confounders, impaired overall executive function significantly increased the probability of being overweight (odds ratio [OR] = 2.47; 95% confidence interval [CI] 1.33 to 4.56). A similar trend of association was also found between impaired inhibition and overweight status (OR = 2.33; 95%CI 1.11 to 4.90). Furthermore, poor working memory was associated with both overweight and obe- sity (OR = 1.87; 95%CI 1.09 to 3.20 and OR = 1.74; 95%CI 1.09 to 2.78, respectively). Our data suggest that deficits in executive function, particularly inhibition and working memory, are associated with weight excess in preschoolers. Early promotion of executive function may be needed at this developmental age to prevent unhealthy weight status. Competing interests: The authors have declared that no competing interests exist. EF involves the high-level mental processes required to control thoughts, emotions, and behaviors. Three fundamental EFs are inhibitory control/inhibition, working memory, and cognitive flexibility/shifting [10]. These three core EFs contribute to higher-order EF, such as problem-solving, reasoning, and planning [10]. EF develops dramatically in the preschool period [11], corresponding to the time of decline in body fat mass, before reaching the inflec- tion point of adiposity rebound (adiposity rebound usually occurs about 6 years of age) [12]. The energy expenditure to develop the brain, especially the area of the brain related to EF, dur- ing this early childhood might influence the composition of body fat and the changes in body mass index (BMI) later [13, 14]. Several studies investigating the correlation between lower EF and higher BMI have focused mainly on school-age children, adolescents, and adults [15–18]. Most of the key results from these studies are found to be a small to medium effect size of the association. A paucity of stud- ies regarding EF and weight excess has been conducted on preschool children due to the rela- tively low prevalence of overweight and obesity in preschoolers (whose body fat typically declines during this period) and the scarcity of valid instruments to measure EF in this age group [19]. Furthermore, the results of some studies conducted on young children are incon- sistent. For example, Pieper and Laugero reported that BMI percentile was not correlated with most measures of EF in children 3–6 years old [20]. Tandon and colleagues showed that effort- ful control and delay ability were not associated with BMI changes [21]. Similarly, a recent study by Gross and colleagues reported that the EF score was not a predictor of weight status in preschoolers [22]. On the other hand, Hughes and colleagues indicated that eating self-regu- lation was related to the child’s BMI-for-age z-scores [23]. Schmitt and colleagues also sug- gested a negative correlation between the composite EF score and BMI percentile in preschoolers [24]. Due to a few studies focusing on young children and the inconsistent results mentioned above, this study aims to investigate the association between EF and weight excess in pre- school-aged children by controlling for potential confounders reviewed from previous litera- ture. The findings of this study may contribute to an understanding of the relationship between these variables in early childhood and obesity intervention by promoting EF. Introduction Funding: This work was supported by the Faculty of Medicine, Chiang Mai University (Grant number 087/2564 to Narueporn Likhitweerawong) (https:// www.med.cmu.ac.th/web/research/). The funders had no role in study design, data collection and Children and adolescents are increasingly facing the health problems of weight excess. The worldwide prevalence of overweight and obesity in young children has continuously increased over the past few decades, regardless of geography and culture [1]. In the conceptual 1 / 13 PLOS ONE | https://doi.org/10.1371/journal.pone.0275711 October 10, 2022 PLOS ONE Association between executive function and excess weight in preschoolers understanding of obesity, it is a chronic metabolic disease that primarily involves increased calorie intake and decreased physical exercise. To date, the evidence is apparent that obesity is a multifactorial disease, originating not only from obesity-related behaviors but also influenced by genetics, environments, and gene-environment interactions [2]. Robust evidence has dem- onstrated several risk factors associated with weight excess in childhood, such as preterm, low birth weight, lack of breastfeeding, excessive screen time, and deficient amount of sleep [3–7]. Neurocognition, particularly executive function (EF), has been assumed to contribute to excess weight through the theoretical hypothesis of lacking control related to eating behaviors [8, 9]. understanding of obesity, it is a chronic metabolic disease that primarily involves increased calorie intake and decreased physical exercise. To date, the evidence is apparent that obesity is a multifactorial disease, originating not only from obesity-related behaviors but also influenced by genetics, environments, and gene-environment interactions [2]. Robust evidence has dem- onstrated several risk factors associated with weight excess in childhood, such as preterm, low birth weight, lack of breastfeeding, excessive screen time, and deficient amount of sleep [3–7]. Neurocognition, particularly executive function (EF), has been assumed to contribute to excess weight through the theoretical hypothesis of lacking control related to eating behaviors [8, 9]. analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist. Competing interests: The authors have declared that no competing interests exist. Measures Study determinants–executive function. The parent-report version of the Behavior Rat- ing Inventory of Executive Function–Preschool version (BRIEF-P) in Thai was used to mea- sure EF of the child [25]. There were 63 items with a three-point Likert scale asking whether each behavior issue is problematic relative to other children of the same age, as never, some- times, or often in the preceding six months. BRIEF-P measured overall EF (global executive composite) and EF subscales (i.e., inhibit, shift, emotional control, working memory, and plan/organize). The T-score for each scale was calculated based on standardized age and sex. Participants were categorized into impaired or normal EF groups, according to the cut-off point (T-score at or above 65), which was considered clinically significant regarding the diffi- culty of executive functioning [25]. This tool demonstrated good reliability with a Cronbach’s alpha of 0.80–0.95 for the EF subscales and global executive composite scale [25]. Study endpoints–weight status. The weight status was divided into three groups: 1) nor- mal weight group was defined as preschoolers with BMI equal to or greater than the 5th per- centile but not reaching the 85th percentile for children of the same age and sex; 2) overweight group was defined as preschoolers with BMI equal to or greater than the 85th percentile but not reaching the 95th percentile; 3) obesity group was defined as preschoolers with BMI equal to or greater than the 95th percentile [26]. The body weight and height of the participants were measured at school using a digital weighing scale and stadiometer by teachers or school nurses. Then, the outcome assessors computed the percentile of BMI. Pre-specified confounders. Potential confounders of overweight/obesity, including child’s age, sex, birth weight, gestational age, breastfeeding, maternal age, maternal BMI, maternal education, socioeconomic status, screen time, physical activity, sleep, and parenting styles, were reviewed from previous literature [3–7, 27–30]. Due to this substantial number of variables contributing to obesity and their potential complex interactions, we created a directed acyclic graph (DAG) using DAGitty [31] to determine confounding factors that require conditioning and to evaluate minimally sufficient adjustment sets of confounders when handling causal assumptions [32], as summarized in S1 Fig. A consensus was reached with all authors (i.e., developmental-behavioral pediatricians and clinical epidemiologists) to determine the conditioning and adjustments of confounders in DAG. Study design and participants This cross-sectional study was conducted on preschoolers from seven public and private schools in Chiang Mai, Thailand, between June to December 2021. Seven participating schools in Chiang Mai represented middle-class socioeconomic status (SES) based on the characteris- tics and facilities of the individual schools, such as the size of the school, number of students, teaching facilities, and school fees. The inclusion criteria were children aged 2–5 years and studying at the pre-kindergarten or kindergarten level. The exclusion criteria were 1) under- weight children (BMI less than the 5th percentile); 2) children diagnosed with neurodevelop- mental disorders or genetic diseases reported by parents (e.g., autism spectrum disorder, PLOS ONE | https://doi.org/10.1371/journal.pone.0275711 October 10, 2022 2 / 13 PLOS ONE Association between executive function and excess weight in preschoolers attention-deficit/hyperactivity disorder, intellectual disability, and Down syndrome); 3) not being ethnically Thai; and 4) parents refusing to participate in the study. This study was approved by the Research Ethics Committee of the Faculty of Medicine, Chiang Mai Univer- sity (051/2564). Before participating in the research, all parents/guardians of the child were informed of the relevant study detail. Their written informed consent was obtained. PLOS ONE | https://doi.org/10.1371/journal.pone.0275711 October 10, 2022 Measures Age, sex, birth weight, gestational age, breastfeeding, maternal age, maternal BMI, maternal education, and screen time were evaluated using a general questionnaire. SES was assessed using the parent-report family income and classified into low (a monthly family income of not more than 18,000 Thai baht aTHB), and high SES (a monthly family income of over 85,000 THB) based on the Thai SES classification [33]. Physical activity and sleep questions were developed to assess the child’s duration of moderate to vigorous physical activity and sleep. These questions were validated and found to be acceptable in reliability and validity, as pre- sented in S1 Table. Parenting styles were evaluated and classified into authoritative, authoritar- ian, and permissive styles based on Baumrind [34] using the Short Form of Parenting Styles and Dimensions Questionnaires (PSDQ)–Thai version [35]. PSDQ demonstrated good reli- ability and validity [35]. 3 / 13 PLOS ONE | https://doi.org/10.1371/journal.pone.0275711 October 10, 2022 PLOS ONE Association between executive function and excess weight in preschoolers Sample size The sample size was calculated using the combination of ‘comparing two independent means’ and ‘rule of thumb of logistic regression’ methods, and then the largest sample size would be selected. Using the comparing two independent means method with alpha 0.05 (two-sided test), power 0.80, and effect size (mean and SD) from the previous study [24] required at least 500 samples, while using the rule of thumb of logistic regression needed at least 600 samples (overweight 60/obesity 60/normal weight 480) to evaluate six factors (5 EF subscales and 1 global executive composite scale), considering the prevalence of overweight and obesity approximately 10–20% [1, 36–38]. Finally, the total sample sizes of the overweight, obesity, and normal weight groups were at least 72, 72, and 576 individuals, respectively, considering an expected incomplete data/no response rate of 20%. Baseline characteristics and comparing variables among individuals with overweight, obesity, and normal weight A total of 1,181 healthy children were included in this study, as presented in the study flow dia- gram (Fig 1). The baseline characteristics are shown in Table 1. The potential variables contrib- uting to weight excess categorized by weight status are presented in Table 2. The results show that there are significant differences in the variables of birth weight (p = 0.002), breastfeeding (p = 0.042), and maternal weight status (p < 0.001) across the three groups. Statistical analysis Statistical analyses in this study were performed using Stata version 16 (StataCorp, College Sta- tion, Texas, USA) [39]. We used frequency (%), mean (SD), and median (IQR) to report descriptive statistics. To evaluate statistically significant differences between groups, the exact probability test and the one-way ANOVA test were performed for categorical data and nor- mally distributed continuous data, respectively. The study endpoint “weight status” were con- sidered as three discrete categories: overweight, obesity, and normal weight (a reference category) in the polynomial logistic regression model, rather than a range in the ordinal one. Although it was likely to have severity grading of weight excess (i.e., overweight and obesity), it could not be guaranteed that there is an association between the levels of the variables in this context of EF impacting weight excess. However, the goodness of fit of the two models was compared using the log-likelihood ratio test with no significant differences between the two models. Therefore, we selected the polynomial logistic regression as our representative model to assess the association between executive functioning and overweight/obesity in preschool- ers. We also performed a multivariable polynomial logistic regression analysis separately for each EF subscale/global executive composite scale on weight status and reported the odds ratio estimates with 95% CI. We used a pairwise deletion technique to handle missing data. Statisti- cal significance was defined as a p-value of less than 0.05. Comparing executive function among individuals with overweight, obesity, and normal weight For EF T-scores, overweight and obesity groups have higher T-scores on all EF subscales and global executive composite scale compared to the normal weight group, as presented in Fig 2A. The result also shows that the working memory subscale has the highest T-score compared to the other EF subscales. No significant differences are found in T-scores between the three groups in most of the EF subscales and global executive composite scale, except for the 4 / 13 PLOS ONE | https://doi.org/10.1371/journal.pone.0275711 October 10, 2022 PLOS ONE Association between executive function and excess weight in preschoolers Fig 1. Study flow diagram. https://doi.org/10.1371/journal.pone.0275711.g001 Fig 1. Study flow diagram. https://doi.org/10.1371/journal.pone.0275711.g001 https://doi.org/10.1371/journal.pone.0275711.g001 marginally significant contribution of the working memory subscale (p = 0.045). After using a Bonferroni method for the multiple pairwise comparisons of the working memory subscale among the three groups, there are no significant differences in the T-scores between groups. When categorizing EF T-scores into EF status based on the cut-off point (impaired EF and normal EF), overweight and obesity groups show a higher percentage of participants with impaired EF than normal weight group on the global executive composite scale and most EF subscales, except for emotional control and plan/organize, as shown in Fig 2B. There is a sig- nificant difference only in the global executive composite scale (p = 0.005) between the three groups. After using the exact probability test for pairwise comparison for the global executive composite scale, the significant difference in the percentage of participants is found only in the normal weight and overweight groups (p = 0.001), while the other two comparisons (normal weight vs. obesity groups and overweight vs. obesity groups) do not show significant differences. PLOS ONE | https://doi.org/10.1371/journal.pone.0275711 October 10, 2022 Association between executive function and excess weight The association between EF and excess weight using multivariable polynomial logistic regres- sion (overweight vs. normal weight groups and obesity vs. normal weight groups) is presented in Table 3. After adjusting for confounders, the significant odds ratio observed in the polyno- mial logistic regression model (overweight vs. normal weight groups) indicates that individuals with impaired inhibition, working memory, and global EF are more likely to be overweight compared to those with normal EFs. The polynomial logistic regression model (obesity vs. normal weight groups) suggests that participants with impaired working memory are signifi- cantly associated with higher odds of being obese compared to those with normal working memory. The increased probability of being both overweight and obese is associated with impaired working memory. However, the effect of impaired working memory on overweight PLOS ONE | https://doi.org/10.1371/journal.pone.0275711 October 10, 2022 5 / 13 PLOS ONE Association between executive function and excess weight in preschoolers Table 1. General characteristics of the study participants. Characteristic No. of participants (Total N = 1,181) Value Male, n (%) 1,181 546 (46.23) Age (years), mean (SD) 1,181 4.68 (0.85) Grade, n (%) 1,181 Pre-kindergarten 93 (7.87) Kindergarten-1 260 (22.02) Kindergarten-2 477 (40.39) Kindergarten-3 351 (29.72) BMI, mean (SD) 1,181 16.38 (2.48) BMI percentile, median (IQR) 1,181 58.20 (29.80, 88.40) Weight status, n (%) 1,181 Normal weight 860 (72.82) Overweight 126 (10.67) Obesity 195 (16.51) Maternal age (years), mean (SD) 1,157 35.53 (5.02) Maternal weight status, n (%) 1,081 Normal weight 816 (75.49) Overweight 193 (17.85) Obesity 72 (6.66) Maternal educational level, n (%) 1,134 Lower than bachelor’s degree 250 (22.05) Bachelor’s degree or higher 884 (77.95) Socioeconomic status, n (%) 1,125 Low 174 (15.47) Middle 831 (73.87) High 120 (10.67) Abbreviations: BMI: body mass index; SD: standard deviation; IQR: interquartile range. https://doi org/10 1371/journal pone 0275711 t001 Table 1. General characteristics of the study participants. vs. normal weight does not significantly differ from the effect of impaired working memory on obesity vs. normal weight (X2 = 0.05, p = 0.832). vs. normal weight does not significantly differ from the effect of impaired working memory on obesity vs. normal weight (X2 = 0.05, p = 0.832). vs. normal weight does not significantly differ from the effect of impaired working memory on obesity vs. normal weight (X2 = 0.05, p = 0.832). PLOS ONE | https://doi.org/10.1371/journal.pone.0275711 October 10, 2022 Discussion After adjusting for confounders using multivariable polynomial regression analysis, we found the associations between overall EF/EF subscales and excess weight. These associations were: i) overall EF was significantly related to the overweight status, but not obesity; ii) EF subscale– inhibition was significantly associated with overweight, but not obesity; and iii) EF subscale– working memory was significantly related to both overweight and obesity. For the overall EF, this study was in line with previous studies that showed lower EF was significantly associated with weight excess [24, 40, 41]. Evidence shows that executive dysfunc- tion can cause excess weight through unhealthy lifestyle behaviors such as increased high-calo- rie intake, decreased fruit/vegetable consumption, less physical activity, and more sedentary behaviors [17]. However, when we categorized excess weight into overweight and obesity sepa- rately, a significant association remained only in overweight. In our opinion, deficits in overall executive functioning in young children may not be a strong factor contributing to obesity, as seen in the previous study [41]. As we all know, additional factors contribute to obesity, such as genetics, eating behaviors, physical activity, and parenting and feeding styles. Most of the PLOS ONE | https://doi.org/10.1371/journal.pone.0275711 October 10, 2022 6 / 13 Association between executive function and excess weight in preschoolers PLOS ONE Table 2. Possible variables contributing to weight excess categorized by weight status. Variables No. of participants (Total N = 1,181) Obesity group (n = 195) Overweight group (n = 126) Normal weight group (n = 860) p-value Male, n (%) 1,181 99 (50.77) 61 (48.41) 386 (44.88) 0.289 Age (years), mean (SD) 1,181 4.78 (0.82) 4.77 (0.82) 4.64 (0.85) 0.052 Gestational age, n (%) 999 Preterm 41 (23.98) 20 (17.70) 115 (16.08) 0.058 Term 130 (76.02) 93 (82.30) 600 (83.92) Birth weight, n (%) 1,043 Low birth weight 20 (11.05) 7 (6.19) 54 (7.21) 0.002 Normal birth weight 145 (80.11) 97 (85.84) 671 (89.59) High birth weight 16 (8.84) 9 (7.96) 24 (3.20) Breastfeeding, n (%) 1,041 Never 13 (7.47) 9 (8.11) 37 (4.89) 0.042 No more than 6 months 33 (18.97) 20 (18.02) 98 (12.96) At least 6 months 128 (73.56) 82 (73.87) 621 (82.14) Moderate to vigorous physical activity, n (%) 1,179 Less than 1 hour per day 163 (83.59) 106 (84.13) 711 (82.87) 0.951 At least 1 hour per day 32 (16.41) 20 (15.87) 147 (17.13) Screen use, n (%) 1,171 More than 1 hour per day 140 (72.92) 87 (70.73) 601 (70.21) 0.774 Not more than 1 hour per day 52 (27.08) 36 (29.27) 255 (39.79) Sleep, n (%) 1,176 Adequate amount for age 151 (77.84) 98 (78.40) 715 (83.43) 0.097 Inadequate amount for age 43 (22.16) 27 (21.60) 142 (16.57) Maternal age (years), mean (SD) 1,157 35.82 (5.28) 35.89 (4.78) 35.41 (5.00) 0.419 Maternal weight status, n (%) 1,081 Normal weight 103 (55.98) 88 (76.52) 625 (79.92) <0.001 Overweight 59 (32.07) 20 (17.39) 114 (14.58) Obesity 22 (11.96) 7 (6.09) 43 (5.50) Maternal education level, n (%) 1,134 Lower than bachelor’s degree 52 (27.96) 22 (18.49) 176 (21.23) 0.092 Bachelor’s degree or higher 134 (72.04) 97 (81.51) 653 (78.77) Socioeconomic status, n (%) 1,125 Low 25 (13.23) 16 (13.11) 133 (16.34) 0.314 Middle 150 (79.37) 91 (74.59) 590 (72.48) High 14 (7.41) 15 (12.30) 91 (11.18) Parenting styles, n (%) 1,168 Authoritative 187 (97.91) 123 (98.40) 826 (96.95) 0.973 Authoritarian 0 (0) 0 (0) 4 (0.47) Permissive 4 (2.09) 2 (1.60) 22 (2.58) Abbreviations: SD: standard deviation. h //d i /10 1371/j l 0275711 002 Table 2. Possible variables contributing to weight excess categorized by weight status. contributing to weight excess categorized by weight status. PLOS ONE time, access to food and eating behaviors in young children depends on parental management of the food environment. Therefore, the EF of children may not have a direct and robust impact on their weight [22]. time, access to food and eating behaviors in young children depends on parental management of the food environment. Therefore, the EF of children may not have a direct and robust impact on their weight [22]. p g When considering the aspect of EF subscales, we found only inhibition and working mem- ory related to excess weight. This finding was consistent with the previous study that showed a PLOS ONE | https://doi.org/10.1371/journal.pone.0275711 October 10, 2022 7 / 13 PLOS ONE Association between executive function and excess weight in preschoolers Fig 2. Boxplot and bar chart. The boxplot depicting T-scores of executive function subscales/global executive composite scale (a) and bar chart depicting the percentage of the number of children with impaired executive function among three weight status groups (b). https://doi.org/10.1371/journal.pone.0275711.g002 Fig 2. Boxplot and bar chart. The boxplot depicting T-scores of executive function subscales/global executive composite scale (a) and bar chart depicting the percentage of the number of children with impaired executive function among three weight status groups (b). https://doi.org/10.1371/journal.pone.0275711.g002 https://doi.org/10.1371/journal.pone.0275711.g002 significant association between these EF subscales and weight excess [42, 43]. For EF subscale– inhibition, the possible link between inhibition and the risk of having excess weight is unhealthy eating behaviors. For example, children with lower inhibition usually have larger self-served portions and more food servings, display more compulsive overeating due to diffi- culties inhibiting response to food stimuli, and have less control to eat despite the absence of hunger [9, 23]. Subsequently, all these obesity-related eating behaviors lead to excess weight in later life. For EF subscale–working memory, working memory is the fundamental EF support- ing self-regulation and inhibitory control by holding mental representation, cutting off distrac- tions, and maintaining behaviors to achieve long-term goals [44, 45]. The explanation of the association between working memory and weight excess is that, in terms of maintaining a healthy weight, working memory helps engage with healthy habits and consequently leads to favorable physical health outcomes [46]. Unlike working memory, inhibition was significantly associated with overweight but not obesity. The undetectable association between inhibition and obesity in this study may reflect, to some extent, the clues to the direction of the association. PLOS ONE | https://doi.org/10.1371/journal.pone.0275711 October 10, 2022 PLOS ONE Impaired inhibitory control could precede weight excess through overeating and obesity-related behavior mechanisms. Nonethe- less, inhibition is not a sufficiently potent factor by itself to affect obesity, and hence it merely produces overweight. Conversely, working memory deficit could be a result from excessive weight via inflammation activity. Inflammatory responses from adipose tissue chronically induce brain alterations via neurohormonal transport perturbation, endothelial-neurovascular disruption, and ultimately changes in cortical gray matter and microstructure of white matter, 8 / 13 PLOS ONE | https://doi.org/10.1371/journal.pone.0275711 October 10, 2022 PLOS ONE Association between executive function and excess weight in preschoolers Table 3. Multivariable polynomial logistic regression analysis of weight status outcome and executive function subscales/global executive function scalea (N = 799). Executive Function Obesity groupb Overweight groupb mORc (95% CI) p-value mORc (95% CI) p-value Impaired inhibit 1.84 (0.94–3.61) 0.077 2.33 (1.11– 4.90) 0.026 Impaired shift 1.71 (0.66–4.45) 0.268 2.32 (0.86– 6.22) 0.095 Impaired emotional control 0.60 (0.15–2.31) 0.457 0.80 (0.17– 3.81) 0.777 Impaired working memory 1.74 (1.09–2.78) 0.019 1.87 (1.09– 3.20) 0.023 Impaired plan/organize 0.66 (0.31–1.41) 0.280 1.07 (0.47– 2.42) 0.866 Impaired overall executive function (GEC) 1.30 (0.73–2.34) 0.374 2.47 (1.33– 4.56) 0.004 Abbreviations: mOR: multivariable polynomial logistic regression odds ratio; 95% CI: 95% confidence interval; GEC: global executive composite. a note that the multivariable polynomial logistic regression models were separately executed for each executive function subscales/global executive composite scale. b the reference group was the normal weight group. c adjusted for age, gender, gestational age, birth weight, breastfeeding, maternal age, maternal weight status, maternal education, socioeconomic status, parenting styles, screen use, moderate to vigorous intensity of physical activity, and sleep variables. https://doi.org/10.1371/journal.pone.0275711.t003 Table 3. Multivariable polynomial logistic regression analysis of weight status outcome and executive function subscales/global executive function scalea (N = 799). c adjusted for age, gender, gestational age, birth weight, breastfeeding, maternal age, maternal weight status, maternal education, socioeconomic status, parenting styles, screen use, moderate to vigorous intensity of physical activity, and sleep variables. https://doi.org/10.1371/journal.pone.0275711.t003 which connect areas of the brain that facilitate working memory [47–49]. Therefore, once obe- sity presents, both overweight and obesity can impair working memory. However, there may be a bidirectional effect between these EFs and weight excess [15, 50]. Executive dysfunction may lead to a cycle of obesogenic behaviors and excess weight, which in turn induces inflam- matory activity in the EF-related brain areas, resulting in impaired executive control over time [46]. PLOS ONE | https://doi.org/10.1371/journal.pone.0275711 October 10, 2022 PLOS ONE We did not find a significant association between the other EF subscales (e.g., shifting and planning) and excess weight. Our finding contrasts with a previous study that reported shifting was significantly negatively correlated with the BMI percentile in preschool children [24]. This could be from the prior study that used performance tasks to assess EF, while our study used the parent-report BRIEF-P questionnaire. Another explanation is that a relatively low number of participants identified impaired shifting, which decreased the power to detect the significant association. The possible reason for the absence of significant relationships between planning and weight status is that planning is a higher-level EF that needs time to develop; thus, this ability at the younger age of our study is comparable among the normal weight and over- weight/obesity groups. The strength of our study is that we conducted a large sample size of typically developing preschool-aged children. We used DAG to manage the potential source of confounding for causal assumptions, which is an efficient and systematic method [51]. The findings found in PLOS ONE | https://doi.org/10.1371/journal.pone.0275711 October 10, 2022 9 / 13 PLOS ONE Association between executive function and excess weight in preschoolers this study support the body of knowledge in the prevention and early intervention of child- hood obesity by promoting EF since early childhood. Emerging EF-targeted interventions such as computerized EF training and episodic future thinking, adjunct to the mainstay treat- ment of obesity, are mostly in preliminary studies but promising therapeutic paradigms to help promote EF and weight loss-related behaviors in children [52]. There are some limitations to this study. Firstly, we were unable to conclude the association as a causal relationship due to the cross-sectional nature of the design. Secondly, an indirect measure, such as BMI, may not be the best representative measure of obesity as body fat. How- ever, BMI could be a good substitute for measuring obesity, as it is closely related to body fat, particularly in prepubescent children [53]. Thirdly, we were unable to examine all potential associated factors of weight excess, including unmeasured genetic effects that might confound the weight excess outcomes. Nonetheless, we collected maternal BMI and weight status as sur- rogate variables of genetic influence. Fourthly, there were a large number of sample exclusions; however, this study yielded sufficient power to detect the differences in executive functioning between weight status groups. PLOS ONE Lastly, there could be benefits and weaknesses due to the homo- geneity of the middle-class SES samples included in this study. This sample homogeneity could facilitate controlling covariates between individuals as they shared common ethnic and cultural behaviors, but it might limit the generalizability of the study to the low-/high-class SES populations. In conclusion, this study found an association between deficits in EF and weight excess in preschoolers. The result suggests that inhibition and working memory might be key compo- nents of such a relationship. Strategies directly targeting the promotion of EF, specifically inhi- bition and working memory, in early childhood might help young children maintain a healthy weight throughout their developmental period. However, longitudinal studies are needed to investigate further the causal effect between EF and weight excess, and the treatment effect of EF intervention on weight outcomes. Acknowledgments The authors thank these people comprising: Prof. Weerasak Chonchaiya for translating the PSDQ and BRIEF-P into the Thai version; Mahippathorn Chinnapha, Eric B Tedstrom, and the Language Learning Center team for editing and proofreading the manuscript; and all chil- dren and their parents for participating in this study. Supporting information S1 Fig. Directed acyclic graph (DAG). DAG presents the causal model of the association between executive function and overweight/obesity. Thirteen confounders (ancestor of expo- sure and outcome) were determined as the minimal sufficient adjustment sets for estimating the effect of executive function on overweight/obesity. (TIF) Author Contributions Conceptualization: Narueporn Likhitweerawong, Jiraporn Khorana, Nonglak Boonchoo- duang, Phichayut Phinyo, Jayanton Patumanond, Orawan Louthrenoo. PLOS ONE | https://doi.org/10.1371/journal.pone.0275711 October 10, 2022 10 / 13 PLOS ONE Association between executive function and excess weight in preschoolers Data curation: Narueporn Likhitweerawong. Formal analysis: Narueporn Likhitweerawong, Jiraporn Khorana. Investigation: Narueporn Likhitweerawong, Orawan Louthrenoo. Methodology: Narueporn Likhitweerawong, Jiraporn Khorana, Nonglak Boonchooduang, Phichayut Phinyo, Jayanton Patumanond, Orawan Louthrenoo. Supervision: Jiraporn Khorana, Nonglak Boonchooduang, Phichayut Phinyo, Jayanton Patu- manond, Orawan Louthrenoo. Validation: Narueporn Likhitweerawong. Writing – original draft: Narueporn Likhitweerawong. Writing – review & editing: Narueporn Likhitweerawong, Jiraporn Khorana, Nonglak Boonchooduang, Phichayut Phinyo, Jayanton Patumanond, Orawan Louthrenoo. Data curation: Narueporn Likhitweerawong. Formal analysis: Narueporn Likhitweerawong, Jiraporn Khorana. Formal analysis: Narueporn Likhitweerawong, Jiraporn Khorana. Investigation: Narueporn Likhitweerawong, Orawan Louthrenoo. nvestigation: Narueporn Likhitweerawong, Orawan Louthrenoo. Methodology: Narueporn Likhitweerawong, Jiraporn Khorana, Nonglak Boonchooduang, Phichayut Phinyo, Jayanton Patumanond, Orawan Louthrenoo. Methodology: Narueporn Likhitweerawong, Jiraporn Khorana, Nonglak Boonchooduang, Phichayut Phinyo, Jayanton Patumanond, Orawan Louthrenoo. Supervision: Jiraporn Khorana, Nonglak Boonchooduang, Phichayut Phinyo, Jayanton Patu- manond, Orawan Louthrenoo. Validation: Narueporn Likhitweerawong. Validation: Narueporn Likhitweerawong. Writing – original draft: Narueporn Likhitweerawong. Writing – original draft: Narueporn Likhitweerawong. Writing – review & editing: Narueporn Likhitweerawong, Jiraporn Khorana, Nonglak Boonchooduang, Phichayut Phinyo, Jayanton Patumanond, Orawan Louthrenoo. References 1. World Health Organization (WHO). Obesity and overweight. 2021. Available from: https://www.who.int/ news-room/fact-sheets/detail/obesity-and-overweight 2. Lin X, Li H. Obesity: epidemiology, pathophysiology, and therapeutics. Frontiers in Endocrinology. 2021;12. https://doi.org/10.3389/fendo.2021.706978 3. Ou-Yang MC, Sun Y, Liebowitz M, Chen CC, Fang ML, Dai W, et al. Accelerated weight gain, prematu- rity, and the risk of childhood obesity: a meta-analysis and systematic review. PLoS One. 2020; 15(5): e0232238. https://doi.org/10.1371/journal.pone.0232238 PMID: 32369502 4. Andriani H. Birth weight and childhood obesity: effect modification by residence and household wealth. Emerging Themes in Epidemiology. 2021; 18(1):6. https://doi.org/10.1186/s12982-021-00096-2 PMID: 33975611 5. Yan J, Liu L, Zhu Y, Huang G, Wang PP. The association between breastfeeding and childhood obesity: a meta-analysis. BMC Public Health. 2014; 14(1):1267. https://doi.org/10.1186/1471-2458-14-1267 PMID: 25495402 6. Fang K, Mu M, Liu K, He Y. Screen time and childhood overweight/obesity: a systematic review and meta-analysis. Child: Care, Health and Development. 2019; 45(5):744–53. https://doi.org/10.1111/cch. 12701 7. Miller MA, Kruisbrink M, Wallace J, Ji C, Cappuccio FP. Sleep duration and incidence of obesity in infants, children, and adolescents: a systematic review and meta-analysis of prospective studies. Sleep. 2018; 41(4). https://doi.org/10.1093/sleep/zsy018 8. Byrne M, LeMay-Russell S, Tanofsky-Kraff M. Loss-of-control eating and obesity among children and adolescents. Current Obesity Reports. 2019;8. https://doi.org/10.1007/s13679-019-0327-1 9. Fogel A, McCrickerd K, Goh AT, Fries LR, Chong Y-S, Tan KH, et al. Associations between inhibitory control, eating behaviours and adiposity in 6-year-old children. International Journal of Obesity. 2019; 43(7):1344–53. https://doi.org/10.1038/s41366-019-0343-y PMID: 30923368 10. Diamond A. Want to optimize executive functions and academic outcomes? simple, just nourish the human spirit. In: Zelazo PD, Sera MD, editors. Minnesota Symposia on Child Psychology. 2014; 37:205–32. https://doi.org/10.1002/9781118732373.ch7 PMID: 25360055 11. Garon N, Bryson SE, Smith IM. Executive function in preschoolers: a review using an integrative frame- work. Psychological Bulletin. 2008; 134(1):31–60. https://doi.org/10.1037/0033-2909.134.1.31 PMID: 18193994 12. Rolland-Cachera MF, Deheeger M, Bellisle F, Sempe´ M, Guilloud-Bataille M, Patois E. Adiposity rebound in children: a simple indicator for predicting obesity. The American Journal of Clinical Nutrition. 1984; 39(1):129–35. https://doi.org/10.1093/ajcn/39.1.129 PMID: 6691287 13. Blair C, Kuzawa CW, Willoughby MT. The development of executive function in early childhood is inversely related to change in body mass index: evidence for an energetic tradeoff? Developmental Sci- ence. 2020; 23(1):e12860. https://doi.org/10.1111/desc.12860 PMID: 31102547 14. Kuzawa CW, Blair C. A hypothesis linking the energy demand of the brain to obesity risk. Proceedings of the National Academy of Sciences. 2019; 116(27):13266–75. https://doi.org/10.1073/pnas. References 1816908116 PMID: 31209026 11 / 13 PLOS ONE | https://doi.org/10.1371/journal.pone.0275711 October 10, 2022 PLOS ONE Association between executive function and excess weight in preschoolers 15. Favieri F, Forte G, Casagrande M. The executive functions in overweight and obesity: a systematic review of neuropsychological cross-sectional and longitudinal studies. Frontiers in Psychology. 2019; 10:2126. https://doi.org/10.3389/fpsyg.2019.02126 PMID: 31616340 16. Mamrot P, Hanć T. The association of the executive functions with overweight and obesity indicators in children and adolescents: a literature review. Neuroscience & Biobehavioral Reviews. 2019; 107:59– 68. https://doi.org/10.1016/j.neubiorev.2019.08.021 PMID: 31470031 17. Liang J, Matheson BE, Kaye WH, Boutelle KN. Neurocognitive correlates of obesity and obesity-related behaviors in children and adolescents. International Journal of Obesity. 2014; 38(4):494–506. https:// doi.org/10.1038/ijo.2013.142 PMID: 23913029 18. Pearce AL, Leonhardt CA, Vaidya CJ. Executive and reward-related function in pediatric obesity: a meta-analysis. Childhood Obesity. 2018; 14(5):265–79. https://doi.org/10.1089/chi.2017.0351 PMID: 29874102 19. O’Meagher S, Norris K, Kemp N, Anderson P. Examining the relationship between performance-based and questionnaire assessments of executive function in young preterm children: implications for clinical practice. Child Neuropsychology. 2019; 25(7):899–913. https://doi.org/10.1080/09297049.2018. 1531981 PMID: 30301415 20. Pieper JR, Laugero KD. Preschool children with lower executive function may be more vulnerable to emotional-based eating in the absence of hunger. Appetite. 2013; 62:103–9. https://doi.org/10.1016/j. appet.2012.11.020 PMID: 23211377 21. Tandon P, Thompson S, Moran L, Lengua L. Body mass index mediates the effects of low income on preschool children’s executive control, with implications for behavior and academics. Childhood Obe- sity. 2015; 11(5):569–76. https://doi.org/10.1089/chi.2014.0071 PMID: 26440385 22. Gross AC, Kaizer AM, Vock DM, Siddiqui S, Fox CK. Cognitive, emotional, and behavioral contributors to early childhood weight status. The Journal of Child Health Care. 2019; 23(3):382–91. https://doi.org/ 10.1177/1367493519852462 PMID: 31159558 23. Hughes SO, Power TG, O’Connor TM, Orlet Fisher J. Executive functioning, emotion regulation, eating self-regulation, and weight status in low-income preschool children: how do they relate? Appetite. 2015; 89:1–9. https://doi.org/10.1016/j.appet.2015.01.009 PMID: 25596501 24. Schmitt SA, Korucu I, Jones BL, Snyder FJ, Evich CD, Purpura DJ. Self-regulation as a correlate of weight status in preschool children. Early Child Development and Care. 2019; 189(1):68–78. https://doi. org/10.1080/03004430.2017.1299715 25. Gioia GA, Espy KA, Isquith PK. BRIEF-P: Behavior Rating Inventory of Executive Function-Preschool version: professional manual. Florida: Psychological Assessment Resources; 2003. 26. Barlow SE, and the Expert Committee. Expert committee recommendations regarding the prevention, assessment, and treatment of child and adolescent overweight and obesity: summary report. Pediat- rics. 2007; 120(Supplement_4):S164–S92. https://doi.org/10.1542/peds.2007-2329C 27. References BMC Pediatrics. 2019; 19(1):159. https://doi.org/10.1186/ s12887-019-1540-5 PMID: 31109318 39. StataCorp. Stata Statistical Software: Release 16. College Station. Texas: StataCorp LLC; 2019. 40. Ronan L, Alexander-Bloch A, Fletcher PC. Childhood obesity, cortical structure, and executive function in healthy children. Cerebral Cortex. 2019; 30(4):2519–28. https://doi.org/10.1093/cercor/bhz257 41. Nelson TD, James TD, Hankey M, Nelson JM, Lundahl A, Espy KA. Early executive control and risk for overweight and obesity in elementary school. Child Neuropsychology. 2017; 23(8):994–1002. https:// doi.org/10.1080/09297049.2016.1183606 PMID: 27187746 42. Tomaso CC, James T, Nelson JM, Espy KA, Nelson TD. Longitudinal associations between executive control and body mass index across childhood. Pediatric Obesity. 2022; 17(4):e12866. https://doi.org/ 10.1111/ijpo.12866 PMID: 34725959 43. almusalam S, Asdaq SMB, Almazial N, Alsomali N, Alqahtani N, Mohammed R, et al. Examining the relationship between obesity and memory function in female school children of Riyadh, Saudi Arabia. Journal of King Saud University—Science. 2021; 33(8):101663. https://doi.org/10.1016/j.jksus.2021. 101663 44. Dohle S, Diel K, Hofmann W. Executive functions and the self-regulation of eating behavior: a review. Appetite. 2018; 124:4–9. https://doi.org/10.1016/j.appet.2017.05.041 PMID: 28551113 45. Hofmann W, Schmeichel BJ, Baddeley AD. Executive functions and self-regulation. Trends in Cognitive Sciences. 2012; 16(3):174–80. https://doi.org/10.1016/j.tics.2012.01.006 PMID: 22336729 46. Shields GS, Deer LK, Hastings PD, Hostinar CE. Adiposity, inflammation, and working memory: Evi- dence for a vicious cycle. Brain, Behavior, & Immunity—Health. 2021; 13:100202. https://doi.org/10. 1016/j.bbih.2021.100202 47. Alarco´n G, Ray S, Nagel BJ. Lower working memory performance in overweight and obese adolescents is mediated by white matter microstructure. The Journal of the International Neuropsychological Soci- ety. 2016; 22(3):281–92. https://doi.org/10.1017/S1355617715001265 PMID: 26708324 48. Garcı´a-Garcı´a I, Michaud A, Dadar M, Zeighami Y, Neseliler S, Collins DL, et al. Neuroanatomical dif- ferences in obesity: meta-analytic findings and their validation in an independent dataset. International Journal of Obesity. 2019; 43(5):943–51. https://doi.org/10.1038/s41366-018-0164-4 PMID: 30022057 49. Buie JJ, Watson LS, Smith CJ, Sims-Robinson C. Obesity-related cognitive impairment: the role of endothelial dysfunction. Neurobiology of Disease. 2019; 132:104580. https://doi.org/10.1016/j.nbd. 2019.104580 PMID: 31454547 50. Lowe CJ, Reichelt AC, Hall PA. The prefrontal cortex and obesity: a health neuroscience perspective. Trends in Cognitive Sciences. 2019; 23(4):349–61. https://doi.org/10.1016/j.tics.2019.01.005 PMID: 30824229 51. Piccininni M, Konigorski S, Rohmann JL, Kurth T. Directed acyclic graphs and causal thinking in clinical risk prediction modeling. BMC Medical Research Methodology. 2020; 20(1):179. https://doi.org/10. 1186/s12874-020-01058-z PMID: 32615926 52. Hayes JF, Eichen DM, Barch DM, Wilfley DE. Executive function in childhood obesity: promising inter- vention strategies to optimize treatment outcomes. Appetite. 2018; 124: 10–23. https://doi.org/10. References Heslehurst N, Vieira R, Akhter Z, Bailey H, Slack E, Ngongalah L, et al. The association between mater- nal body mass index and child obesity: a systematic review and meta-analysis. PLoS Med. 2019; 16(6): e1002817. https://doi.org/10.1371/journal.pmed.1002817 PMID: 31185012 28. Ruiz M, Goldblatt P, Morrison J, Porta D, Forastiere F, Hryhorczuk D, et al. Impact of low maternal edu- cation on early childhood overweight and obesity in europe. Paediatric and Perinatal Epidemiology. 2016; 30(3):274–84. https://doi.org/10.1111/ppe.12285 PMID: 26945670 29. Bridger Staatz C, Kelly Y, Lacey RE, Blodgett JM, George A, Arnot M, et al. Socioeconomic position and body composition in childhood in high- and middle-income countries: a systematic review and nar- rative synthesis. International Journal of Obesity. 2021; 45(11):2316–34. https://doi.org/10.1038/ s41366-021-00899-y PMID: 34315999 30. Sokol R, Qin B, Poti J. Parenting styles and body mass index: a systematic review of prospective stud- ies among children. Obesity Reviews. 2017;18. https://doi.org/10.1111/obr.12497 31. Textor J, van der Zander B, Gilthorpe MS, Liskiewicz M, Ellison GT. Robust causal inference using directed acyclic graphs: the R package ’dagitty’. The International Journal of Epidemiology. 2016; 45 (6):1887–94. https://doi.org/10.1093/ije/dyw341 PMID: 28089956 32. Tennant PWG, Murray EJ, Arnold KF, Berrie L, Fox MP, Gadd SC, et al. Use of directed acyclic graphs (DAGs) to identify confounders in applied health research: review and recommendations. International Journal of Epidemiology. 2020; 50(2):620–32. https://doi.org/10.1093/ije/dyaa213 33. Poomontre J, Setthawong P. A prediction system based on the TMRS standardized socio-economic status (SES) classification of Bangkok and Metropolian subjects XIV International Business and Econ- omy Conference (IBEC) Bangkok, Thailand. 2015. http://dx.doi.org/10.2139/ssrn.2550078 34. Baumrind D. The discipline controversy revisited. Family Relations. 1996; 45(4):405–14. https://doi.org/ 10.2307/585170 12 / 13 PLOS ONE | https://doi.org/10.1371/journal.pone.0275711 October 10, 2022 PLOS ONE Association between executive function and excess weight in preschoolers 35. Robinson C, Mandleco B, Olsen S, Hart C. The parenting styles and dimensions questionnaire. Califor- nia: Sage; 2001. 36. Health Systems Research Institute, Mahidol University, Faculty of Medicine Ramathibodi Hospital. Management of obesity and complications [in Thai]. [Cited 2022 August 27]. Available from: http://164. 115.27.97/digital/files/original/596c43663f7bfdb66c2d60d8dd57ccec.pdf 37. Nonboonyawat T, Pusanasuwannasri W, Chanrat N, Wongthanavimok N, Tubngern D, Panutrakul P, et al. Prevalence and associates of obesity and overweight among school-age children in a rural com- munity of Thailand. Korean Journal of Pediatrics. 2019; 62(5):179–86. https://doi.org/10.3345/kjp.2018. 06499 PMID: 30744316 38. Armoon B, Karimy M. Epidemiology of childhood overweight, obesity and their related factors in a sam- ple of preschool children from central Iran. PLOS ONE | https://doi.org/10.1371/journal.pone.0275711 October 10, 2022 References 1016/j.appet.2017.05.040 PMID: 28554851 53. Dencker M, Thorsson O, Linden C, Wollmer P, Andersen L, Karlsson M. BMI and objectively measured body fat and body fat distribution in prepubertal children. Clinical Physiology and Functional Imaging. 2007; 27:12–6. https://doi.org/10.1111/j.1475-097X.2007.00709.x PMID: 17204032 13 / 13 PLOS ONE | https://doi.org/10.1371/journal.pone.0275711 October 10, 2022
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Pharmacological effects and target analysis of Guipi wan in the treatment of cerebral ischemia-reperfusion injury
Frontiers in pharmacology
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OPEN ACCESS KEYWORDS guipi wan, ischemia-reperfusion injury, network analysis, GABBR1, PI3K/AKT KEYWORDS guipi wan, ischemia-reperfusion injury, network analysis, GABBR1, PI3K/AKT frontiersin.org TYPE Original Research PUBLISHED 07 March 2024 DOI 10.3389/fphar.2024.1346226 TYPE Original Research PUBLISHED 07 March 2024 DOI 10.3389/fphar.2024.1346226 TYPE Original Research PUBLISHED 07 March 2024 DOI 10.3389/fphar.2024.1346226 guipi wan, ischemia-reperfusion injury, network analysis, GABBR1, PI3K/AKT OPEN ACCESS Jianfeng Zhang1†, Li Luo 2†, Yanyan Guo2, An Liu2, Mengjia Zhang3, Wei Jiang2, Xi Li2, Qingqing Liu2 and Jiaoyan Yu2* 1Department of Pharmacy, Eighth Hospital of Xi’an City, Xi’an, China, 2Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi’an, China, 3Air Force Medical University, Xi’an, China Guipi wan (GPW) is a traditional Chinese medicine commonly used in clinical practice, typically to treat neurological diseases such as neurasthenia and traumatic brain injury. It may have positive effects on cerebral ischemia‒ reperfusion injury (cI/R). This study aimed to assess the effects of GPW in a mouse model of cI/R and find its possible targets. C57BL/6J mice were used to establish the cI/R model, and the laser speckle doppler was used to determine the success of the model. GPW was administered intragastrically for 7 days, brain tissue sections were stained with TTC, HE, and TUNEL, Western blot assay was performed to detect the effect of apoptosis-related proteins. Furthermore, we screened active ingredients from the TCM Database and constructed a compound‒target network using the Cytoscape 3.8.0 software. Moreover, we employed protein‒protein interaction and component‒target‒pathway network analyses to determine the potential components of GPW and its target genes, the key target was verified through molecular docking. Finally, we detected the influence of the downstream signaling pathway of the target through Western blot. The results showed that GPW decreased the cerebral infarction area, neurological function scores, and neuronal apoptosis in mice by regulating PI3K/AKT signaling pathway. Network analysis indicated that gamma- aminobutyric acid B receptor 1 (GABBR1) might be a potential target for the treatment of cI/R. Molecular docking indicated that 9 active components in GPW could bind to GABBR1 with desirable binding energy. This study represented the demonstratable effect of GPW in the treatment of cI/R injury and suggested GABBR1 as a potential target using network analysis. Front. Pharmacol. 15:1346226. doi: 10.3389/fphar.2024.1346226 COPYRIGHT © 2024 Zhang, Luo, Guo, Liu, Zhang, Jiang, Li, Liu and Yu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Pharmacological effects and target analysis of Guipi wan in the treatment of cerebral ischemia-reperfusion injury OPEN ACCESS EDITED BY Junfeng Wang, Massachusetts General Hospital and Harvard Medical School, United States REVIEWED BY Shuang Pan, Tufts University, United States Weirong Wang, Xi’an Jiaotong University, China *CORRESPONDENCE Jiaoyan Yu, 969027046@qq.com †These authors have contributed equally to this work RECEIVED 29 November 2023 ACCEPTED 19 February 2024 PUBLISHED 07 March 2024 CITATION Zhang J, Luo L, Guo Y, Liu A, Zhang M, Jiang W, Li X, Liu Q and Yu J (2024), Pharmacological effects and target analysis of Guipi wan in the treatment of cerebral ischemia- reperfusion injury. Front. Pharmacol. 15:1346226. doi: 10.3389/fphar.2024.1346226 OPEN ACCESS EDITED BY Junfeng Wang, Massachusetts General Hospital and Harvard Medical School, United States REVIEWED BY Shuang Pan, Tufts University, United States Weirong Wang, Xi’an Jiaotong University, China *CORRESPONDENCE Jiaoyan Yu, 969027046@qq.com †These authors have contributed equally to this work RECEIVED 29 November 2023 ACCEPTED 19 February 2024 PUBLISHED 07 March 2024 CITATION Zhang J, Luo L, Guo Y, Liu A, Zhang M, Jiang W, Li X, Liu Q and Yu J (2024), Pharmacological effects and target analysis of Guipi wan in the treatment of cerebral ischemia- reperfusion injury. Front. Pharmacol. 15:1346226. doi: 10.3389/fphar.2024.1346226 1 Introduction Ischemic stroke (IS) is the second leading cause of death worldwide and shows a high disability rate (Walter., 2022). It accounts for 70% of all strokes and carries a high risk of long-term recurrence. In 2019, the total number of IS-related deaths reached 3.29 million, accounting for 50.3% of stroke deaths and 17.7% of all cardiovascular disease-related deaths. And research predictive analysis suggested that this number could increase to 4.9 million by 2030 (Fan et al., 2023). Ischemic stroke occurs when blood flow to the brain is blocked due 01 Frontiers in Pharmacology frontiersin.org Zhang et al. 10.3389/fphar.2024.1346226 FIGURE 1 GPW reduces the brain damage caused by cerebral ischemia/reperfusion injury (cI/R). (A) Laser speckle Doppler shows the success of cI/R induction. (B) Neurological function score. N = 8 (C) Representative images of TTC staining in brain sections from different experimental groups. (D) Quantitative assessments of the infarct area from TTC staining. N = 6; #p < 0.01 versus the sham group; *p < 0.05, **p < 0.01 compared with the Model group. FIGURE 1 GPW reduces the brain damage caused by cerebral ischemia/reperfusion injury (cI/R). (A) Laser speckle Doppler shows the success of cI/R induction. (B) Neurological function score. N = 8 (C) Representative images of TTC staining in brain sections from different experimental groups. (D) Quantitative assessments of the infarct area from TTC staining. N = 6; #p < 0.01 versus the sham group; *p < 0.05, **p < 0.01 compared with the Model group. Codonopsis radix, Atractylodes macrocephala rhizoma, Astragali radix, Glycyrrhizae radix et rhizoma, Poria, Polygalae radix, The seed of Ziziphus jujuba var. Spinos, Longan arillus, Angelicae sinensis radix, Aucklandiae radix and Jujubae fructus. Clinical experimental studies have confirmed that Astragali radix can significantly recover the clinical symptoms of cerebral ischemia, and play anti-atherosclerosis and neuroprotective roles. (Li et al., 2023a). Atractylenolide III in Atractylodes macrocephala Koidz ameliorates cerebral ischemic injury and neuroinflammation associated with inhibiting JAK2/STAT3/Drp1-dependent mitochondrial fission in microglia (Zhou et al., 2019). Several medicinal materials and components of GPW have been reported to improve cerebral ischemia reperfusion injury (Hao et al., 2023). These results suggest that GPW, as a clinical prescription of traditional Chinese medicine, may be effective in treating cerebral ischemia-reperfusion injury, but the underlying pharmacological mechanism remains unclear. to a blocked or ruptured artery, disrupting the brain’s energy supply, causing tissue damage, and leading to widespread neuronal death (Tuo et al., 2022). Frontiers in Pharmacology frontiersin.org 1 Introduction The current treatment for this condition is the use of a recombinant tissue plasminogen activator, which triggers intravenous thrombolysis. However, the window for this treatment is narrow, and patients often face the risk of permanent disability after a stroke (Lin and Lang, 2022). In addition, blood flow restoration can cause more serious cerebral ischemia‒reperfusion injury (cI/R) (Campbell and Khatri, 2019). Therefore, a reliable treatment plan is urgently needed to improve the disability and nerve damage caused by reperfusion injury after a stroke. To date, many drugs have been experimentally shown to have neuroprotective effects, but their clinical application has not yet been confirmed (Tsivgoulis et al., 2023). Specifically, traditional Chinese medicine (TCM) has been used to treat patients during the recovery period after a stroke, and many compound prescriptions have been demonstrated to be effective (Tao et al., 2020). Guipi wan (GPW) is often used to treat neurasthenia and traumatic brain injury, and also to improve the emotional and cognitive dysfunctions that arise after stroke (Li et al., 2020). It mainly comprises 11 traditional Chinese active ingredients, including The systemic nature of TCM, which comprises multiple components with numerous downstream targets and complex mechanisms of action, cannot be accurately captured by the principles of Western medical research, which focuses on individual targets and components. Consequently, the Western 02 frontiersin.org Zhang et al. 10.3389/fphar.2024.1346226 FIGURE 2 GPW alleviates the pathological damage of model mice. (A) Hematoxylin and eosin staining results of infarct area (20×). (B) Nissl staining results of infarct area (20×), The black arrow shows the Nissl corpuscles. (C) Numerical analysis of Nissl staining with ImageJ program. (D) TUNEL staining results of brain tissue sections in different experimental groups. (E) Statistical analysis of the percentage of intact neurons in the infarct area of mice by TUNEL staining. Scale bar = 75 μm; N = 6 mice per group; #p < 0.01 versus the sham group; *p < 0.05, **p < 0.01 compared with the Model group. FIGURE 2 GPW alleviates the pathological damage of model mice. (A) Hematoxylin and eosin staining results of infarct area (20×). (B) Nissl staining results of infarct area (20×), The black arrow shows the Nissl corpuscles. (C) Numerical analysis of Nissl staining with ImageJ program. (D) TUNEL staining results of brain tissue sections in different experimental groups. (E) Statistical analysis of the percentage of intact neurons in the infarct area of mice by TUNEL staining. 1 Introduction Scale bar = 75 μm; N = 6 mice per group; #p < 0.01 versus the sham group; *p < 0.05, **p < 0.01 compared with the Model group. FIGURE 2 GPW alleviates the pathological damage of model mice. (A) Hematoxylin and eosin staining results of infarct area (20×). (B) Nissl staining results of infarct area (20×), The black arrow shows the Nissl corpuscles. (C) Numerical analysis of Nissl staining with ImageJ program. (D) TUNEL staining results of brain tissue sections in different experimental groups. (E) Statistical analysis of the percentage of intact neurons in the infarct area of mice by TUNEL staining. Scale bar = 75 μm; N = 6 mice per group; #p < 0.01 versus the sham group; *p < 0.05, **p < 0.01 compared with the Model group. signaling pathway was verified, with the intent to elucidate elucidate the therapeutic effect and molecular mechanism of GPW on cI/R injury. approach has not been satisfactory in elucidating the pharmacodynamics of TCM compound prescriptions (Li et al., 2023b). However, with the advancement of network analysis techniques, more and more studies have begun to use this method to conduct holistic and systematic exploration to explain the mechanism of action of Chinese herbal medicine (Wang et al., 2021a), thus broadening their range of clinical applications. Many studies have successfully used network analysis to explain how effectively these drugs treat various diseases. Therefore, this study intends to combine pharmacological experiments and network analysis techniques to clarify the efficacy and possible targets of GPW in the treatment of cI/R. Frontiers in Pharmacology frontiersin.org 2.2 MCAO model underwent middle cerebral artery occlusion (MCAO) under anesthesia and then were administered a gastric injection with 0.9% saline or GPW extract (Lanzhou Foci Pharmaceutical, Lanzhou, 200,934, China). The MCAO model was established with a modified suture method (Barthels and Das, 2020) After intraperitoneal injection of sodium pentobarbital anesthetized, the mouse was fixed in the supine position. Following alcohol disinfection of the neck skin, we incised the midline of the neck, bluntly separating the right common carotid artery (CCA), external carotid artery (ECA), and internal carotid artery (ICA). We threaded the CCA, ICA, and ECA separately. Next, we clamped the proximal end of the CCA and the ICA, and tied the two cords at the proximal end of the ECA to a dead knot, while we tied the cords at the proximal end of the ECA to a slipknot. We cut a small “V" between the two cords at the proximal end of the ECA, inserted the thread plug, and insert the thread. We tightened the proximal end of the ECA line, fixed the line tether, lifted the ECA, and untied the ICA arterial clamp. We then slowly pushed the line tether toward the ICA. When the thread end entered about 1.2 cm, we stopped when we felt some resistance. We then untied the CCA artery clip, at this time. The end of the thread plug was just at the beginning of the middle cerebral artery (MCA), causing an occlusion. After 2 h of ischemia, the thread plug was pulled out to generate the ischemia‒reperfusion model. GPW extraction process: Codonopsis radix (80 g), Atractylodes macrocephala rhizoma (60 g), Astragali radix (80 g), Glycyrrhizae radix et rhizoma (40 g), Poria (160 g), Polygalae radix (160 g). The seed of Ziziphus jujuba var. Spinosa (80 g), Longan arillus (160 g), Angelicae sinensis radix (160 g), Aucklandiae radix (40 g), Jujubae fructus (40 g), total 1,000 g. 2.1 Animals and drug administration Adult male C57BL/6J mice aged 6–8 weeks, weighing 20–25 g, were provided by the Experimental Animal Center of the Fourth Military Medical University. The mice were housed at a constant temperature of 25°C ± 2°C and humidity of 50% ± 10%, with an alternating 12 h light/dark cycle and free access to food and water, they were randomly divided into five groups. Four groups This study confirmed that GPW has a significant therapeutic effect on cI/R model mice, in addition, predicted that GABBR1 is an important target for its therapeutic effect, and the downstream 03 frontiersin.org frontiersin.org Zhang et al. 10.3389/fphar.2024.1346226 FIGURE 3 Effect of GPW on apoptosis-related proteins. (A) Western blot detection of caspase 3, cleaved-caspase 3, Bax, and Bcl-2 bands in the brain tissue of each group of mice. (B–E) Statistical analysis of protein expression. N = 6 mice per group; #p < 0.01 versus the sham group; *p < 0.05, **p < 0.01 compared with the Model group. FIGURE 3 Effect of GPW on apoptosis-related proteins. (A) Western blot detection of caspase 3, cleaved-caspase 3, Bax, and Bcl-2 bands in the brain tissue of each group of mice. (B–E) Statistical analysis of protein expression. N = 6 mice per group; #p < 0.01 versus the sham group; *p < 0.05, **p < 0.01 compared with the Model group. 2.2 MCAO model Codonopsis radix, Angelicae sinensis radix, Glycyrrhizae radix et rhizoma and Aucklandiae radix were crushed into fine powder, and the other medicinal materials 10 times the volume of water boiled 2 times, for 2 h each time, combined and concentrated into extract, and mixed with fine powder to make pill, weighing about 167 g, that is, 1,000 g of crude drug is equivalent to 167 g of extract, The quality of the extract was identified and the content of astragaloside in the extract detected by HPLC was 0.33 mg/g, which met the extraction requirement of ≥0.1 mg/g in Chinese Pharmacopoeia, as shown in Supplementary Figure S1. During gastric administration, 1 g extract was dissolved in 10 mL normal saline to obtain 6 g crude drug/1g extract/10 mL GPW administration solution. The clinical dose of drug 15 g crude drug/60 kg used in humans was converted to approximately 3 g crude drug/kg in mouse, with a proportion of 12.3 times based on body surface areas (Reagan-Shaw et al., 2008), this dose was selected as the medium dose group. The low, medium and high doses calculated by the equal ratio of 2 times were 1.5, 3 and 6 crude drugs/kg. These values corresponded to the extract dosage of 0.25, 0.5, 1 g/kg, thereby obtaining the intragastric volume of 2.5 mL/kg, 5 mL/kg, and 10 mL/kg, respectively. The remaining group underwent a sham operation and then received intragastric administration of 0.9% normal saline. Frontiers in Pharmacology 2.3 Laser speckle Doppler Mice were anesthetized by intraperitoneal injection of 1% sodium pentobarbital solution at 50 μg/kg of body weight. Once anesthetized, the head was fixed on the operating table, the skin was cut along the midline, connective tissue was removed, and brain blood flow images were collected by laser speckle doppler flow imager (RFLSI 111). Frontiers in Pharmacology 04 frontiersin.org Zhang et al. 10.3389/fphar.2024.1346226 FIGURE 4 GPW component selection and target prediction. (A) The active ingredients of GPW and their targets are represented by nodes. The circles represent the plant components of GPW, the number of the corresponding compound is found in Supplementary Table S1, the polygons of different colors represent the main components of each plant, and the purple square represents the relevant target of the component. Edges represent the interaction between the biologically active ingredient and the target. (B) The Venn diagram of GPW and cI/R targets. Purple represents component targets, yellow represents disease targets, and the intersection represents common targets. (C) Protein‒protein interaction network diagram. Nodes represent different proteins, and lines represent interactions. FIGURE 4 GPW component selection and target prediction. (A) The active ingredients of GPW and their targets are represented by nodes. The circles represent the plant components of GPW, the number of the corresponding compound is found in Supplementary Table S1, the polygons of different colors represent the main components of each plant, and the purple square represents the relevant target of the component. Edges represent the interaction between the biologically active ingredient and the target. (B) The Venn diagram of GPW and cI/R targets. Purple represents component targets, yellow represents disease targets, and the intersection represents common targets. (C) Protein‒protein interaction network diagram. Nodes represent different proteins, and lines represent interactions. Frontiers in Pharmacology 2.8 TUNEL staining Sections were washed twice for 5 min with xylene. After gradient ethanol immersion, sections were infused with proteinase K to increase cell permeability and incubated at 37°C for 20 min. Next, sections were first incubated with 100 μL of TUNEL (6- Diamidino-2-phenylindole) reaction mixture (ab66110, Abcam) at 37°C for 1 h under dark conditions, and then with 100 μL DAB solution at room temperature for 10 min. Counterstaining with hematoxylin was performed for 3 min and, after rinsing, sections were dehydrated in a graded series of ethanol, made transparent in xylene, and mounted on neutral gum. The number of TUNEL-positive cells was counted under a fluorescence microscope (Ts2-FL, Nikon), and the percentage of TUNEL-positive cells was calculated to calculate the rate of apoptosis. 2.4 Neurological scores 2021). According to this method, a score of 0–4 corresponds to no neurological dysfunction, inability to fully extend the left front paw, hovering left, falling left, low level of consciousness and inability to walk autonomously. A score of 5 represents death. After model establishment and drug or saline administration, neurological deficits were assessed with a 5 point scoring system, as previously described (Kuai et al., 05 frontiersin.org Zhang et al. 10.3389/fphar.2024.1346226 TABLE 1 Compounds screened according to degree value and druggability. Molecule name Degree Molecule name Degree Nuciferine 31 Selina-4(14),7(11)-dien-8-one 11 Atractylone 19 (−)-Caryophyllene oxide 11 Beta-carotene 19 5,6,7,8-Tetrahydro-2,4-dimethylquinoline 11 3β-Acetoxyatractylone 17 Benzo [a]carbazole 16 Juniper camphor 10 Coumarin 14 Harman 10 Harmine 13 Ermanthin 9 (+/−)-Isoborneol 13 2-[(2R,5S,6S)-6,10-dimethylspiro [4.5]dec-9-en-2-yl]propan-2-ol 9 α-Cubebol 13 (5E,9Z)-3,6,10-trimethyl-4,7,8,11-tetrahydrocyclodeca [b]furan 11 (5E,9Z)-3,6,10-trimethyl-4,7,8,11-tetrahydrocyclodeca [b]furan TABLE 2 The top 20 targets out of 213 possible GPW targets. Target name Degree Target name Degree GABBR1 38 SLC6A2 15 PTGS2 30 ADRB2 13 CHRM1 29 ADRA1A 13 CHRM2 29 GABRA3 13 CHRM3 28 BCHE 12 NCOA2 21 GABRA6 12 GABRA2 20 ADRA1B 13 PTGS1 18 SCN5A 10 PRSS3 16 SLC6A3 10 CHRNA7 16 RXRA 10 brain tissue structure was observed under an optical microscope (Ts2-FL, Nikon, Tokyo, Japan). TABLE 2 The top 20 targets out of 213 possible GPW targets. 2.7 Nissl staining Paraffin sections were sequentially dehydrated with xylene, and absolute, 95%, 80%, and 70% ethanol. Sections were then washed with distilled water, soaked in 1% tar violet dye for 10 min, washed with distilled water again, and decolorized with gradient ethanol immersion. After becoming transparent, sections were mounted on clear slides with neutral gum, and tissue was observed under an optical microscope. 2.5 2,3,5-Triphenyltetrazolium chloride staining After 24 h, the mice in each group were deeply anesthetized, their brain tissue was removed, and residual blood was washed out with normal saline. Brains were then quickly frozen at −20°C for 20 min and cut into 2 mm slices with a brain slice mold (68,714, RWD Life Science). Sections were stained with 1% 2,3,5- triphenyltetrazolium chloride (TTC, purity >98.0%; Sigma- Aldrich, St Louis, MO, United States) for 30 min at 37°C. ImageJ software (NIH) was used to measure the percentage of tissue affected by cerebral infarction. Frontiers in Pharmacology frontiersin.org 2.9 Western blotting For Western blotting, 20 mg of brain tissue from the infarct area was lysed in 100 μL RIPA buffer, and homogenized by ultrasonication. Samples were centrifuged at 12,000 rpm for 10 min at 4 °C. The supernatant was removed, and the total Brain tissue was immersed in 4% paraformaldehyde for 24 h and then embedded in paraffin. Thereafter, 4-μm-thick sections were prepared for hematoxylin and eosin (HE) staining. After dehydration with a gradient series of ethanol and xylene, the 06 frontiersin.org Zhang et al. 10.3389/fphar.2024.1346226 FIGURE 5 Enrichment analysis of core targets. (A) The top 10 results for the biological process (BP), cell component (CC), and molecular function (MF) categories in Gene Ontology (GO) annotation analysis. The y-axis represents the target-enriched GO, and the x-axis represents the gene number in the GO annotation results. (B) Top 20 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment bubble chart (p < 0.05). The y-axis represents the name of the enriched pathway, and the x-axis represents the enrichment value. FIGURE 5 Enrichment analysis of core targets. (A) The top 10 results for the biological process (BP), cell component (CC), and molecular function (MF) categories in Gene Ontology (GO) annotation analysis. The y-axis represents the target-enriched GO, and the x-axis represents the gene number in the GO annotation results. (B) Top 20 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment bubble chart (p < 0.05). The y-axis represents the name of the enriched pathway, and the x-axis represents the enrichment value. protein concentration in each sample was quantified by bicinchoninic acid assay (Pierce BCA Protein Assay Kit; Thermo Fisher Scientific, Waltham, MA, United States). After heating the samples in the presence of a loading buffer, SDS- PAGE (sodium dodecyl sulphate-polyacrylamide gel electrophoresis) was performed on 8–10% gels. Proteins were later transferred to PVDF membranes, which were blocked in 5% skim milk for 1 h and incubated at 4°C overnight with primary antibodies (1:1,000 dilution) for PI3K (13666S; Cell Signaling Technology, Danvers, MA, United States), AKT (2920ST, Cell Signaling Technology), P-AKT (13038S, Cell Signaling Technology), caspase-3 (9664T, Cell Signaling Technology), cleaved caspase-3 (9664s, Cell Signaling Technology), Bcl-2 (3498s, Cell Signaling Technology), Bax (14796s, Cell Signaling Technology), and β-actin (059M4770v, Sigma- Aldrich). After repeated washing, membranes were incubated with secondary antibodies (1:5,000 dilution) at room temperature for 1 h and subsequently washed. 2.9 Western blotting Membranes were then observed and photographed through a gel imager (Bio-Rad, United States). ImageJ was utilized to analyze the relative expression levels of the proteins, with β-actin as a reference. (DL) ≥0.1, and blood‒brain barrier (BBB) ≥1 (Liu et al., 2020). The information concerning the main active compounds of GPW and their corresponding targets was collected and standardized through the Uniport database (https://www.uniprot.org/), and the gene names of each target were obtained. 2.11 Compound-target network construction Cytoscape 3.8.0 (National Institute of General Medical Sciences, Bethesda, MD, United States) was used to construct a compound- target network for GPW. We also used the GeneCards (https://www. genecards.org/), OMIM (https://omim.org) and DisGeNET (https:// www.disgenet.org/) databases with cI/R as the keyword to acquire the key therapeutic targets for cI/R. The downstream targets of GPW and cI/R were imported into the online platform of Venny 2.1.0 for analysis, and Venn diagrams were used to visualize the common targets of GPW and cI/R injury. Frontiers in Pharmacology 2.10 Target prediction of GPW components The common targets were imported into the STRING database (https://string-db.org/), and “multiple proteins” and “Homo sapiens” were selected to obtain protein-protein interaction (PPI) data. This information was imported into Cytoscape 3.8.0 to perform a visual analysis by drawing PPI network diagrams. The CytoHubba plug-in was employed for network topology analysis (Athanasios et al., 2017). We selected targets with a degree higher than the average as the key targets in the PPI network. We used the Traditional Chinese Medicine System Pharmacological Analysis Platform (TCMSP, http://tcmspw.com/ tcmsp.php) and the Bioinformatics Analysis Tool for Molecular mechanism of Traditional Chinese Medicine (BATMAN-TCM) database (http://bionet.ncpsb.org/batman-tcm) to identify the main active compounds of GPW. The screening conditions were the following: oral bioavailability (OB) ≥30%, drug-like activity 07 frontiersin.org Zhang et al. 10.3389/fphar.2024.1346226 FIGURE 6 Representative results of molecular docking analyses. (A) Binding of the positive control baclofen to GABBR1. (B) Representative docking results of 3 GPW components. b1: (−)-Caryophylleneoxide; b2: 3β-acetoxyatractylone; b3: Ermanthin. FIGURE 6 Representative results of molecular docking analyses. (A) Binding of the positive control baclofen to GABBR1. (B) Representative docking results of 3 GPW components. b1: (−)-Caryophylleneoxide; b2: 3β-acetoxyatractylone; b3: Ermanthin. Frontiers in Pharmacology 2.14 Molecular docking studies concerning the lowest binding energy resulting from molecular docking was obtained. The lower the binding energy, the stronger the binding force between the active ingredient and the target protein: a drug molecule with binding energy ≤−5. 0 kJ/mol is considered to have a good binding activity to the target (Li et al., 2021). The main chemical components and the core targets obtained from database screening were verified by molecular docking analyses (Taha et al., 2020). The structures of the key components were searched on the PubChem database (http://zinc. docking. org/), optimized, and saved in. mol format (Xia et al., 2020). The Cryo-EM structure of GABBR1 was downloaded from the Protein Data Bank (PDB) and saved in. pdb format. Water molecules and the docking ligand were removed with the PyMOL software (Schrödinger, New York, NY, United States). The obtained protein structures were then imported into AutoDock (Center for Computation Structural Biology, The Scripps Research Institute, La Jolla, CA, United States) to apply pre treatments such as hydrogenation. The active ingredients of GPW and the target proteins were saved as. pdbqt files, and AutoDock was utilized to simulate the docking of each active ingredient and target protein. The data 2.13 Gene function annotation and pathway enrichment analysis Finally, Cytoscape 3.8.0 was employed to construct a component‒target‒path (CTP) network to study the reciprocity of components, targets, and paths (Cui et al., 2020). In such a network, the degree value of a node was defined as the number of edges connected to the rest of the network, where each edge corresponds to the interaction between a biologically active ingredient and its target, thus representing the physiological relevance of the node in the network. To study the potential molecular mechanism through which GPW exerts positive effects on cI/R, the key targets were analyzed by gene function annotation (Gene Ontology, GO), and pathway enrichment analysis (Kyoto Encyclopedia of Genes and Genomes, KEGG). Statistical significance was set at p < 0.05. 08 frontiersin.org Zhang et al. 10.3389/fphar.2024.1346226 TABLE 3 Molecular docking results between ligands and core target receptors. Molecule name Binding energy (kcal/mol) Baclofen (GABBR1 agonist)PTGS2 −7.0 3β-acetoxyatractylone −5.3 (+/−)-Isoborneol −4.2 α-Cubebol −5.1 Selina-4(14),7(11)-dien-8-one −3.4 (−)-Caryophyllene oxide −6.3 Juniper camphor −4.8 2-[(2R,5S,6S)-6,10-dimethylspiro [4.5]dec-9-en-2-yl]propan-2-ol −5.7 Ermanthin −5.8 FIGURE 7 Effect of GPW on PI3K/AKT signaling pathways in the infarct area. (A) WB representative result chart. (B) Statistical analysis results of PI3K expression. (C) Quantitative statistical results of AKT expression. (D) Quantitative statistical results of the p-AKT expression. N = 6 mice per group; #p < 0.01 versus the sham group; *p < 0.05, **p < 0.01 compared with the Model group. TABLE 3 Molecular docking results between ligands and core target receptors. Molecule name Binding energy (kcal/mol) Baclofen (GABBR1 agonist)PTGS2 −7.0 3β-acetoxyatractylone −5.3 (+/−)-Isoborneol −4.2 α-Cubebol −5.1 Selina-4(14),7(11)-dien-8-one −3.4 (−)-Caryophyllene oxide −6.3 Juniper camphor −4.8 2-[(2R,5S,6S)-6,10-dimethylspiro [4.5]dec-9-en-2-yl]propan-2-ol −5.7 Ermanthin −5.8 FIGURE 7 Effect of GPW on PI3K/AKT signaling pathways in the infarct area. (A) WB representative result chart. (B) Statistical analysis results of PI3K expression. (C) Quantitative statistical results of AKT expression. (D) Quantitative statistical results of the p-AKT expression. N = 6 mice per group; #p < 0.01 versus the sham group; *p < 0.05, **p < 0.01 compared with the Model group. Frontiers in Pharmacology 3.2 GPW reduced neuronal damage in MCAO mice To predict the target receptor of GPW for the treatment of cI/R, we performed the analysis from three aspects. First, we list the top 20 targets among the 213 possible action targets selected based on the degree values (Table 2) and found theγ-aminobutyric acid receptor (GABBR1) with the degree value of 38. Second, we selected 130 target receptors that are relevant to the treatment of cI/R with GPW from 5,992 (Figure 4B). After drawing the PPI network structure with the STRING database website, 36 targets with degree values greater than the average were obtained for visualization (Figure 4C). The results showed GABBR1 is included in the main genes that can be exploited for treatment of cI/R. Finally, we employed the GO and KEGG pathway enrichment combined with CTP network analysis. As illustrated in Figure 5A, the top 10 biological process (BP), molecular function (MF), and cellular composition (CC) were represented from 130 potential targets. Furthermore, KEGG analysis revealed that 112 signal pathways are involved in GPW-mediated effects on cI/R injury, among which the top 20 were selected to make a bubble map (Figure 5B). According to the results, GPW mainly acts on cI/R injury through neuroactive ligand‒receptor interaction, fluid shear stress, atherosclerosis, calcium signaling pathway, and the cAMP and PI3K/AKT signaling pathways. Interestingly, GABBR1 is a key target in the neuroactive ligand-receptor interaction signaling pathway. Thus, these results, taking three aspects of drug intervention, disease correlation, and pathway enrichment, demonstrated GABBR1 may be an important target for GPW treatment of cI/R. HE staining showed that, in the sham group, hippocampal neuronal cell bodies were large and round with obvious nucleoli, and the cells were arranged in multiple well-organized layers. In the model group, the number of cells on the affected side was reduced, the arrangement was sparse, the cell bodies were shrunken, the nuclei were constricted in triangles, and some cell nuclei had disappeared. On the contrary, the proportion of atrophied neurons in the GPW-treated groups was significantly reduced (Figure 2A). Nissl staining showed the same trend. Compared with the sham group, the number of Nissl bodies in the model group was significantly reduced, while that in GPW-treated model groups was significantly increased (Figures 2B, C). Furthermore, almost no TUNEL-positive cells were observed in the sham group, but their number was significantly increased in the model group. 3.3 GPW decreased the expression of apoptosis-related proteins in MCAO mice The expression of the pro-apoptotic proteins caspase-3, cleaved caspase-3, and Bax was significantly increased in the model group but significantly decreased after GPW administration (Figure 3A‒ D). Accordingly, the expression of the anti-apoptotic protein Bcl-2 was significantly reduced in the model group, while the administration of GPW was able to counteract this decrease (Figure 3E). These results indicated that GPW had the potential to inhibit neuronal apoptosis at the molecular level. 3 Results from 11 herbs (Supplementary Table S1). Using the uniprot databases to normalize cI/R targets and delete duplicates, a total of 213 targets were obtained. Then we used cystoscope software to construct the “component-target network” diagram of GPW (Figure 4A). In this diagram, the “degree” is defined as the number of connected edges in the network, representing the importance of the network. We found a total of 29 compounds with a degree value greater than the average value of 8.76. Among these, we further excluded 12 compounds due to a lack of compatibility with Lipinski’s rules (Chen et al., 2020); 2) the structure conforming to the characteristics of Pan-Assay Interference Compounds (PAINS), which could indicate positive readouts in biochemical assays via different mechanisms (Grigalunas et al., 2020). Thus, only 17 compounds were selected for the prediction of subsequent targets (Table 1). The total blood flow on the ischemic side after reperfusion was measured by laser speckle Doppler, and blood flow recovery was greater than 70%, indicating successful induction of cI/R (Figure 1A). Different doses of GPW significantly improved the neurological score of the model mice (Figure 1B). TTC staining showed that GPW significantly reduced the size and volume of the infarct in the model mice compared with that in the sham operation group (Figures 1C, D). 3.2 GPW reduced neuronal damage in MCAO mice After GPW administration, the number of TUNEL- positive cells in the model mice was reduced in a dose-dependent manner (Figures 2D, E). This further revealed that GPW could reduce neuronal apoptosis of cI/R injury. 3.5 Molecular docking further confirmed that GABBR1 might be a reliable target for GPW therapy cI/R To further explore the binding mechanism of GPW on cI/R, we obtained 8 compounds including 3β-acetoxyatractylone, (+/−)-isoborneol, α-cubebol, selina-4(14),7(11)-dien-8-one, (−)-caryophyllene oxide, juniper camphor, 2-[(2R,5S, 6S)-6,10- dimethylspiro [4.5]dec-9-en-2-yl]propan-2-ol, and ermanthin after intersecting the 17 main components of the preliminary screening with 38 components that interact with GABBR1 (Supplementary Figure S2A). Here, we intend to explore the binding mechanism between these active compounds and GABBR1. As illustrated in Figure 6A, taking baclofen as a probe, 2.15 Statistical analysis All data are expressed as mean ± standard deviation (Mean ± SD). SPSS19.0 (IBM, Armonk, NY, United States) and GraphPad 9.0 (GraphPad, La Jolla, CA, United States) were used for statistical analysis and graph plotting. t-test was used to compare the means of two samples. A one-way analysis of variance and Tukey’s test were employed for comparisons of three or more group means. Statistical significance was set at p < 0.05. 09 frontiersin.org Zhang et al. 10.3389/fphar.2024.1346226 Frontiers in Pharmacology 3 Results 3.1 GPW reduced the cerebral infarction area in MCAO mice 3 Results 3.4 Network analysis predicted the main related targets of GPW The role of GPW in the treatment of cI/R has been determined; further, it is intended to predict its possible targets through network analysis. Through TCMSP, according to the conditions of OB ≥ 30%, DL ≥0.1, and BBB ≥1, 95 active components were selected Frontiers in Pharmacology 10 frontiersin.org Zhang et al. 10.3389/fphar.2024.1346226 prescription in TCM, which has been reported to be effective against many neurological diseases. However, its effect and mechanism of action on cI/R injury have not been reported. This study is of great significance for the development of therapeutic drugs for ischemic stroke based on TCM. prescription in TCM, which has been reported to be effective against many neurological diseases. However, its effect and mechanism of action on cI/R injury have not been reported. This study is of great significance for the development of therapeutic drugs for ischemic stroke based on TCM. we observed baclofen formed one hydrogen bond with Glu251, the alkyl conjugation interactions with Tyr279, and Ile276, and π-π interactions with Tyr250 and Trp278. In addition, the formation of the ligand-receptor complex was also dependent on van der Waals forces with Ser153, Ser131, Trp65, Tyr279, and Phe202. The binding energy of baclofen was −7.0 kcal/mol, indicating the strong binding ability between baclofen and GABBR1. Firstly, we used the classical mouse MCAO model to further evaluate the therapeutic effect of GPW (Walter, 2022). The success of the model was verified by laser speckle Doppler, and GPW was found to reduce cerebral infarction size and neural function score and reduce neuronal apoptosis in model mice. Apoptosis is an important pathway leading to neuronal death after stroke, and caspase-3, bax, and blc-2 are apoptosis-related proteins. We further used WB to find that GPW can counteract these changes in stroke levels. The effect of GPW on cI/R was confirmed by experimental pharmacological methods. Next, we performed the molecular docking between these 8 compounds and GABBR1. As illustrated in Figure 6B; Supplementary Figure S2B, we obtained the binding energies ranked −6.3 to −3.4 kcal/mol (Table 3), whereby suggested that these 8 compounds had good binding ability with GABBR1. Similarly, the formation of these 8 ligand-receptor complexes was also based on the hydrogen bond, conjugation interactions, and van der Waals forces formed by 8 compounds with the above-mentioned key amino acid residues in GABBR1. 3.4 Network analysis predicted the main related targets of GPW In parallel, these results indicated that the mechanism of the interaction between bioactive compound and GABBR1 was similar to that of clinical drugs, thus proving the promising potential of GPW for cI/ R treatment. Next, the main components and targets of cI/R treatment with GPW were screened and predicted by network analysis. Using the TCMSP database and according to OB, DL, and BBB standards, 96 components of 11 kinds of Chinese herbs in GPW were screened out. Further, the degree values were ranked according to the number of corresponding targets, those less than the average are excluded, and those greater than the average are 29 in total. The druggability of the compound requires compliance with Lipinski’s Rule of Five and the PAIN rule, which further excludes some compounds, S-(2- Carboxyethyl)-L-Cysteine and Stigmasterol meet the druggability rules, but there are many targets and poor specificity. Therefore, 17 compounds such as nuciferine, atractylone, β-carotene, and coumarin were obtained. Among these, previous studies have shown that nuciferine was found to significantly improve neurological deficit scores, cerebral edema, and infarction by regulating fat metabolism and inflammatory response (Wu et al., 2020). Similarly, patients with higher serum β-carotene were found to have a significantly lower risk of stroke and death (Huang et al., 2018). Additionally, coumarin is a common oral anticoagulant used for the prevention and treatment of stroke (Cordonnier, 2018). These findings, together with our results, confirm that the core components of GPW can effectively reduce cI/R injury. However, although atractylone, 3β-acetoxyatractylone, and harmine have not been reported to have a therapeutic effect on ischemic stroke, they may play a synergistic role in the treatment of GPW, which needs to be verified by subsequent experiments. 3.6 GPW affected the expression of PI3K/ AKT signaling pathway-related proteins It has been shown that modulating GABBR1 can inhibit apoptosis of rat hippocampal neurons through the PI3K/Akt pathway in the treatment of refractory epilepsy. We speculate that GPW may affect the PI3K/AKT signaling pathway by activating GABBR1, Therefore, We used Western blotting to evaluate changes in the expression of the related proteins (Figure 7A). Compared with the sham group, the model group had significantly reduced levels of PI3K, whose expression increased after GPW administration (Figure 7B). Also, while the total expression of AKT did not change (Figure 7C), that of phosphorylated AKT (p-AKT) was significantly reduced in the model group; this reduction was restored in GPW-treated mice (Figure 7D). In summary, the results show that GPW can activate the PI3K/AKT signaling pathway. frontiersin.org Frontiers in Pharmacology 4 Discussion Furthermore, in the results of network analysis, GABBR1 was found to have the highest degree in the target of GPW components. Additionally, combined with the analysis results of PPI, GO, and KEEG analysis found that GABBR1 was closely related to the effect of GPW on cI/R. Combined with the above results, we analyzed and speculated that GABBR1 may be a key target for the treatment of cI/ R by GPW. Molecular docking provides further validation and suggests that multiple components in GPW may synergistically act on GABBR1 to produce neuroprotective effects. GABBR1 is the metabolic receptor 1 subtype of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA), It is a G protein-coupled receptor expressed in neurons and glial cells throughout the brain (Cediel et al., 2022). GABBR1 exerts presynaptic and postsynaptic effects to inhibit the release of neurotransmitters and produce a later inhibitory postsynaptic potential, respectively (Gassmann and Bettler, 2012). It has been shown that GABBR1 controls neuronal activity to prevent overexcitation, thereby preventing excitotoxicity In this study, we validated the pharmacological effect of GPW in the treatment of cI/R injury. The prevention and treatment of ischemic stroke remain a worldwide challenge. A central issue is the risk of bleeding associated with anticoagulants and antiplatelet drugs (Sandercock et al., 2015). Due to its low side effects, TCM is often sought as an alternative drug therapy for ischemic stroke prevention and rehabilitation intervention in China. Natural medicines in TCM are the origin of many new medicines, such as Salvia miltiorrhiza, which has been used to treat cerebrovascular diseases in China for thousands of years. TCM has been used in humans for more than 2,000 years. The valuable experience provided by this practice can provide powerful guidance for drug discovery (Sun et al., 2015). However, there are still some limitations of TCM, such as the low quality of TCM tests and unclear ingredients and mechanisms. GPW in this study is a classic 11 frontiersin.org Zhang et al. 10.3389/fphar.2024.1346226 study was conducted in accordance with the local legislation and institutional requirements. study was conducted in accordance with the local legislation and institutional requirements. and cell death. Selective continuous activation of GABBR1 can provide neuroprotection in vitro and in vivo models of cerebral ischemia (Kim et al., 2014). Moreover, studies have shown that the GABBR-mediated PI3K/AKT signaling pathway can reduce oxidative stress and neuronal cell damage in rat models of Alzheimer’s disease (Sun et al., 2020). 4 Discussion After a stroke, activation of the PI3K/AKT signaling pathway can counteract neuronal apoptosis (Lv et al., 2019). Further, we found that GPW reduced the amount of PI3K protein in cI/R mice and inhibited the phosphorylation of AKT. Our analysis showed that GPW may be mediated by GABBR1 to produce neuroprotective effects in cI/R injury by activating PI3K/AKT signaling. Publisher’s note All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher. Funding The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by the project of Shaanxi Provincial Administration of Traditional Chinese Medicine (grant number 2021-ZZ-JC030), Tangdu Hospital National Natural Science Foundation Support Program (grant number 2021ZTXM-025). Data availability statement The original contributions presented in the study are included in the article/Supplementary Material, further inquiries can be directed to the corresponding author. 5 Conclusion The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. In conclusion, this study confirmed the neuroprotective effect of GPW by regulating the PI3K/AKT signaling pathway. In addition, the combination of network analysis and molecular docking predicted that GPW might target GABBR1 for the treatment of cI/R, preliminarily indicating that GPW may be a candidate herb for further research. This work provided a theoretical basis for the clinical application of GPW. Author contributions JZ: Writing–original draft. LL: Writing–original draft. YG: Writing–original draft. AL: Writing–review and editing. MZ: Writing–review and editing. WJ: Writing–review and editing. XL: Writing–review and editing. QL: Writing–review and editing. JY: Writing–original draft, Writing–review and editing. It is necessary to acknowledge the limitations of this work. First, the composition and target of GPW are statistically obtained from the database, which cannot contain all the compounds and target genes. Second, the effect of GPW on cerebral ischemia-reperfusion injury needs more clinical verification. Finally, in addition to GABBR1, PTGS2, CHRM1, CHRM3, and other targets are also highly correlated. Whether other components of GPW interact with them and participate in the treatment of cerebral ischemia-reperfusion injury is still unclear, and more experiments are needed to verify it. Ethics statement The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fphar.2024.1346226/ full#supplementary-material The animal study was approved by the Animal Experiment Ethics Committee of Air Force Military Medical University. The Fan, J., Li, X., Yu, X., Liu, Z., Jiang, Y., Fang, Y., et al. (2023). Global burden, risk factor analysis, and prediction study of ischemic stroke. Neurology 101, 137–150. doi:10.1212/ WNL.0000000000207387 Frontiers in Pharmacology Cui, Q., Zhang, Y. L., Ma, Y. H., Yu, H. Y., Zhao, X. Z., Zhang, L. H., et al. (2020). A network pharmacology approach to investigate the mechanism of Shuxuening injection in the treatment of ischemic stroke. J. Ethnopharmacol. 257, 112891. doi:10.1016/j.jep. 2020.112891 References Chen, X., Li, H., Tian, L., Li, Q., Luo, J., and Zhang, Y. (2020). Analysis of the physicochemical properties of Acaricides based on Lipinski’s rule of five. J. Comput. Biol. 27, 1397–1406. doi:10.1089/cmb.2019.0323 Chen, X., Li, H., Tian, L., Li, Q., Luo, J., and Zhang, Y. (2020). Analysis of the physicochemical properties of Acaricides based on Lipinski’s rule of five. J. Comput. Biol. 27, 1397–1406. doi:10.1089/cmb.2019.0323 Athanasios, A., Charalampos, V., Vasileios, T., and Ashraf, G. M. (2017). Protein- protein interaction (PPI) network: recent advances in drug discovery. Curr. Drug Metab. 18 (1), 5–10. doi:10.2174/138920021801170119204832 Cordonnier, C. (2018). Balancing risks versus benefits of anticoagulants in stroke prevention. Lancet Neurol. 17, 487–488. doi:10.1016/s1474-4422(18)30164-9 Barthels, D., and Das, H. (2020). Current advances in ischemic stroke research and therapies. Biochim. Biophys. Acta Mol. Basis Dis. 1866 (4), 165260. doi:10.1016/j.bbadis. 2018.09.012 Cui, Q., Zhang, Y. L., Ma, Y. H., Yu, H. Y., Zhao, X. Z., Zhang, L. H., et al. (2020). A network pharmacology approach to investigate the mechanism of Shuxuening injection in the treatment of ischemic stroke. J. Ethnopharmacol. 257, 112891. doi:10.1016/j.jep. 2020.112891 Campbell, B. C. V., and Khatri, P. (2020). Stroke. Lancet 396 (10244), 129–142. doi:10. 1016/s0140-6736(20)31179-x Campbell, B. C. V., and Khatri, P. (2020). Stroke. Lancet 396 (10244), 129–142. doi:10. 1016/s0140-6736(20)31179-x Cediel, M. L., Stawarski, M., Blanc, X., Nosková, L., Magner, M., Platzer, K., et al. (2022). GABBR1 monoallelic de novo variants linked to neurodevelopmental delay and epilepsy. Am. J. Hum. Genet. 109, 1885–1893. doi:10.1016/j.ajhg.2022. 08.010 Cediel, M. L., Stawarski, M., Blanc, X., Nosková, L., Magner, M., Platzer, K., et al. (2022). GABBR1 monoallelic de novo variants linked to neurodevelopmental delay and epilepsy. Am. J. Hum. Genet. 109, 1885–1893. doi:10.1016/j.ajhg.2022. 08.010 12 frontiersin.org Zhang et al. Zhang et al. 10.3389/fphar.2024.1346226 Gassmann, M., and Bettler, B. (2012). Regulation of neuronal GABA(B) receptor functions by subunit composition. Nat. Rev. Neurosci. 13, 380–394. doi:10.1038/nrn3249 Sandercock, P. A., Counsell, C., Kane, E. J., and Signorini, D. (2015). Anticoagulants for acute ischaemic stroke. Cochrane Database Syst. Rev. 2015, 1451–1462. doi:10.1002/ 14651858.CD000024 Grigalunas, M., Burhop, A., Christoforow, A., and Waldmann, H. (2020). Pseudo- natural products and natural product-inspired methods in chemical biology and drug discovery. Curr. Opin. Chem. Biol. 56, 111–118. doi:10.1016/j.cbpa.2019.10.005 Sun, K., Fan, J., and Han, J. (2015). Ameliorating effects of traditional Chinese medicine preparation, Chinese materia medica and active compounds on ischemia/ reperfusion-induced cerebral microcirculatory disturbances and neuron damage. Acta Pharm. Sin. B 5, 8–24. References doi:10.1016/j.apsb.2014.11.002 Hao, D. L., Li, J. M., Xie, R., Huo, H. R., Xiong, X. J., Sui, F., et al. (2023). The role of traditional herbal medicine for ischemic stroke: from bench to clinic-A critical review. Phytomedicine 109, 154609. doi:10.1016/j.phymed.2022.154609 Sun, Z., Sun, L., and Tu, L. (2020). GABAB receptor-mediated PI3K/Akt signaling pathway alleviates oxidative stress and neuronal cell injury in a rat model of Alzheimers disease. J. Alzheimers Dis. 76, 1513–1526. doi:10.3233/jad-191032 Huang, J., Weinstein, S. J., Yu, K., Männistö, S., and Albanes, D. (2018). Serum beta carotene and overall and cause-specific mortality. Circ. Res. 123 (12), 1339–1349. doi:10. 1161/circresaha.118.313409 Taha, K. F., Khalil, M., Abubakr, M. S., and Shawky, E. (2020). Identifying cancer- related molecular targets of Nandina domestica Thunb. by network pharmacology- based analysis in combination with chemical profiling and molecular docking studies. J. Ethnopharmacol. 249, 112413. doi:10.1016/j.jep.2019.112413 Kim, J. Y., Ho, H., Kim, N., Liu, J., Tu, C. L., Yenari, M. A., et al. (2014). Calcium- sensing receptor (CaSR) as a novel target for ischemic neuroprotection. Ann. Clin. Transl. Neurol. 1, 851–866. doi:10.1002/acn3.118 Tao, T., Liu, M., Chen, M., Luo, Y., Wang, C., Xu, T., et al. (2020). Natural medicine in neuroprotection for ischemic stroke: challenges and prospective. Pharmacol. Ther. 216, 107695. doi:10.1016/j.pharmthera.2020.107695 Kuai, F., Zhou, L., Zhou, J., Sun, X., and Dong, W. (2021). Long non-coding RNA THRIL inhibits miRNA-24-3p to upregulate neuropilin-1 to aggravate cerebral ischemia-reperfusion injury through regulating the nuclear factor κB p65 signaling. Aging (Albany NY) 13 (6), 9071–9084. doi:10.18632/aging.202762 Tsivgoulis, G., Katsanos, A. H., Sandset, E. C., Turc, G., Nguyen, T. N., Bivard, A., et al. (2023). Thrombolysis for acute ischaemic stroke: current status and future perspectives. Lancet Neurol. , 22, 418–429. doi:10.1016/S1474-4422(22)00519-1 Li, M., Lan, R., Wen, Y., Shi, K., and Yang, D. (2020). Guipi decoction for insomnia: systematic review and meta-analysis. Med. Baltim. 99 (27), e21031. doi:10.1097/md. 0000000000021031 Tuo, Q. Z., Zhang, S. T., and Lei, P. (2022). Mechanisms of neuronal cell death in ischemic stroke and their therapeutic implications. Med. Res. Rev. 42, 259–305. doi:10. 1002/med.21817 Li, X., Liu, Z., Liao, J., Chen, Q., Lu, X., and Fan, X. (2023a). Network pharmacology approaches for research of Traditional Chinese Medicines. Chin. J. Nat. Med. 21, 323–332. doi:10.1016/S1875-5364(23)60429-7 Walter, K. (2022). What is acute ischemic stroke? Jama 327, 885. doi:10.1001/jama. 2022.1420 Li, Y., Wang, D., Guo, R., Ma, B., Miao, L., Sun, M., et al. (2023b). References Neuroprotective effect of Astragali Radix on cerebral infarction based on proteomics. Front. Pharmacol. 14, 1162134. doi:10.3389/fphar.2023.1162134 Wang, X., Wang, Z. Y., Zheng, J. H., and Li, S. (2021a). TCM network pharmacology: a new trend towards combining computational, experimental and clinical approaches. Chin. J. Nat. Med. 19 (1), 1–11. doi:10.1016/s1875-5364(21)60001-8 Li, Z. H., Yu, D., Huang, N. N., Wu, J. K., Du, X. W., and Wang, X. J. (2021). Immunoregulatory mechanism studies of ginseng leaves on lung cancer based on network pharmacology and molecular docking. Sci. Rep. 11 (1), 18201. doi:10.1038/ s41598-021-97115-8 Wang, Y., Gai, S., Zhang, W., Huang, X., Ma, S., Huo, Y., et al. (2021b). The GABA(B) receptor mediates neuroprotection by coupling to G(13). Sci. Signal 14 (705), eaaz4112. doi:10.1126/scisignal.aaz4112 Wu, L., Chen, C., Li, Y., Guo, C., Fan, Y., Yu, D., et al. (2020). UPLC-Q-TOF/MS- Based serum metabolomics reveals the anti-ischemic stroke mechanism of nuciferine in MCAO rats. ACS Omega 5 (51), 33433–33444. doi:10.1021/acsomega.0c05388 Lin, K., and Lang, E. (2022). In ischemic stroke upon wakening, IV thrombolysis or EVT improves functional outcome at 90 d. Ann. Intern Med. 175, 41. doi:10.7326/J22-0020 Liu, Y., Xue, Q., Li, A., Li, K., and Qin, X. (2020). Mechanisms exploration of herbal pair of HuangQi-DanShen on cerebral ischemia based on metabonomics and network pharmacology. J. Ethnopharmacol. 253, 112688. doi:10.1016/j.jep.2020.112688 Xia, Q. D., Xun, Y., Lu, J. L., Lu, Y. C., Yang, Y. Y., Zhou, P., et al. (2020). Network pharmacology and molecular docking analyses on Lianhua Qingwen capsule indicate Akt1 is a potential target to treat and prevent COVID-19. Cell. Prolif. 53 (12), e12949. doi:10.1111/cpr.12949 Lv, Y., Liu, W., Ruan, Z., Xu, Z., and Fu, L. (2019). Myosin IIA regulated tight junction in oxygen glucose-deprived brain endothelial cells via activation of TLR4/PI3K/Akt/ JNK1/2/14-3-3ε/NF-κB/MMP9 signal transduction pathway. Cell. Mol. Neurobiol. 39, 301–319. doi:10.1007/s10571-019-00654-y Zhou, K., Chen, J., Wu, J., Wu, Q., Jia, C., Yang, X. Z. X., et al. (2019). Atractylenolide III ameliorates cerebral ischemic injury and neuroinflammation associated with inhibiting JAK2/STAT3/Drp1-dependent mitochondrial fission in microglia. Phytomedicine 59, 152922. doi:10.1016/j.phymed.2019.152922 Reagan-Shaw, S., Nihal, M., and Ahmad, N. (2008). Dose translation from animal to human studies revisited. Faseb J. 22, 659–661. doi:10.1096/fj.07-9574LSF 13 13 Frontiers in Pharmacology Frontiers in Pharmacology frontiersin.org
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Correlation between Heart fatty acid binding protein and severe COVID-19: A case-control study
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Results Of these 46 cases, 16 cases with confirmed COVID-19 were tested for HFABP> 7 ng / mL upon admission; among them, 14 cases were diagnosed with severe COVID-19 within the hospitalization. The Odds ratio of the measured HFABP elevation was 6.81(95% confidence interval [CI] 5.23–8.40), and 3 patients with severe COVID-19 progressed in 5 patients with mild HFABP> 7 ng/mL. Copyright: © 2020 Yin et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Background Heart-fatty acid binding protein (HFABP) has been recognized as a highly heart-specific marker. However, it is currently unknown that its HFABP is also closely related to the sever- ity of COVID-19. Citation: Yin L, Mou H, Shao J, Zhu Y, Pang X, Yang J, et al. (2020) Correlation between Heart fatty acid binding protein and severe COVID-19: A case-control study. PLoS ONE 15(4): e0231687. https://doi.org/10.1371/journal.pone.0231687 RESEARCH ARTICLE Correlation between Heart fatty acid binding protein and severe COVID-19: A case-control study RESEARCH ARTICLE Li Yin1☯, Huaming Mou1☯, Jiang Shao1☯, Ye Zhu2☯, Xiaohua Pang1☯, Jianjun Yang1☯, Jianming Zhang1☯, Wei Shi1☯, Shimei Yu3☯, Hailong WangID1☯* 1 Department of Cardiology, Heart Center, Chongqing Three Gorges Central Hospital, Affiliated Three Gorges Hospital of Chongqing University, Chongqing, China, 2 Department of Cardiology, West China Hospital of Sichuan University, Chengdu, China, 3 Department of Otorhinolaryngology, Wanzhou First People Hospital, Chongqing, China a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 ☯These authors contributed equally to this work. * wangjinlong2007666@163.com * wangjinlong2007666@163.com Methods Editor: Xia Jin, Institut Pasteur of Shanghai Chinese Academy of Sciences, CHINA Editor: Xia Jin, Institut Pasteur of Shanghai Chinese Academy of Sciences, CHINA Editor: Xia Jin, Institut Pasteur of Shanghai Chinese Academy of Sciences, CHINA Received: February 26, 2020 Accepted: March 26, 2020 Published: April 29, 2020 We retrospectively screened 46 patients who met our inclusion criteria within 4 weeks. They were tested for HFABP after the diagnosis of COVID-19, and monitored for HFABP during their hospital stay. We tracked the patients during their hospital stay to determine if they had severe COVID-19 or mild-to-severe transition features. We calculated the chi-square test values found for HFABP to predict the correlation between HFABP levels and the severity of the COVID-19. Peer Review History: PLOS recognizes the benefits of transparency in the peer review process; therefore, we enable the publication of all of the content of peer review and author responses alongside final, published articles. The editorial history of this article is available here: https://doi.org/10.1371/journal.pone.0231687 PLOS ONE PLOS ONE Trial registration Competing interests: No authors have competing interests. Competing interests: No authors have competing interests. Our study has been registered with the Chinese Clinical Trial Registry, the registration num- ber: ChiCTR2000029829. Conclusion These data indicate that the elevation of HFABP is closely related to the severity of COVID- 19 in the patients, and the elevated HFABP may cause rapid development of patients with mild COVID-19 into severe COVID-19. But serum HFABP negative maybe make patients with mild COVID-19 safer, the current data show no effect on the all-cause mortality. Data Availability Statement: All relevant data are within the manuscript and its Supporting Information files. Funding: Unfunded studies. 1 / 7 PLOS ONE | https://doi.org/10.1371/journal.pone.0231687 April 29, 2020 PLOS ONE Correlation between Heart fatty acid binding protein and severe COVID-19: A case-control study Introduction Coronaviruses belong to the Coronaviridae family of non-segmented positive-sense RNA viruses and are widely parasitic in humans and other mammals [1]. Although most infections with human coronavirus are mild, two coronaviruses, including severe acute respiratory syn- drome coronavirus (SARS-CoV) [2–4] and Middle East respiratory syndrome coronavirus (MERS-CoV) [5,6], cause severe infection. They can cause fulminant disease and severe illness. In December 2019, a new coronavirus named 2019 New Coronavirus (2019-nCoV) was found in Wuhan, Hubei, China. The disease caused by this coronavirus is COVID-19 [7–11]. At pres- ent, many cases have been confirmed in all provinces of China and in other countries. For making the diagnosis of patients with COVID-19, it is a great challenge for doctors to deter- mine the condition of patients with severe illness as early as possible. Heart fatty acid-binding protein, a serum biomarker for myocardial injury, is highly cardiac specific [12–14]. Recently, we have found that elevated HFABP levels are associated with severe COVID-19 or mild-to-severe transition features. Our study sought to determine whether the measurement of the HFABP can predict short-term turnover and prognosis in patients with COVID-19. Our study retrospectively analyzed the epidemiological, clinical, and laboratory characteris- tics of patients with COVID-19 and compared HFABP levels with severe COVID-19 and mild-to-severe transition features. We hope that our findings will provide information to the global community about predicting the condition and outcomes of patients with COVID-19. Measurement All blood samples were collected and sent to the laboratory immediately. All selected patients were measured for HFABP. The results were provided to the clinical medical staff. HFABP lev- els were measured by the Roche Modular Analyzer (Roche Diagnostics, Laval, Quebec). These tests were performed with reagents provided by the manufacturer and in strict accordance with the procedures. The cut-off value is defined as the internationally agreed value of 7 ng / mL. Patients and trial designs During January 2020, we retrospectively screened all patients with COVID-19 admitted to Chongqing Three Gorges Central Hospital, and we obtained approval from the Ethics Com- mittee of the Chongqing Three Gorges Central Hospital. Eligible patients included patients older than 14 years of age, patients who were diagnosed with COVID-19, and patients who had been assessed for HFABP serum concentrations at any time during the hospital stay. We excluded patients who were younger than 14 years of age, patients who had not received the measurement of HFABP serum concentrations at any time during the hospital stay. We per- formed follow-up (during the hospital stay, 9–21 days) of the patients in the study and recorded their status (mild, severe, or death) and whether they changed from mild to severe, defined as any of the following conditions: Mild COVID-19: The patient presents with only fever, respiratory tract infection, and other symptoms, and imaging shows pneumonia. Those who have one of the following pathogenic evidences: 1. Real-time fluorescent RT-PCR of respiratory specimens or blood specimens for detection of novel coronavirus nucleic acid; 2. Sequencing of viral genes of respiratory speci- mens or blood specimens, highly homologous to known novel coronavirus. 2 / 7 PLOS ONE | https://doi.org/10.1371/journal.pone.0231687 April 29, 2020 PLOS ONE Correlation between Heart fatty acid binding protein and severe COVID-19: A case-control study Severe COVID-19: confirmed as COVID-19 and meets any of the following criteria: 1. Respi- ratory distress, RR  30 times / min; 2. Means oxygen saturation  93%; Arterial blood oxygen partial pressure (PaO2) / oxygen concentration (FiO2) 300 mmHg (1 mmHg = 0.133 kPa). Death: Total deaths from all causes during the hospital stay. Patients During the research period, 245 patients arrived at our hospital and were diagnosed with COVID-19. Of these patients, 199 patients were excluded from our research because they did not undergo testing for serum HFABP within a week of admission, and 46patients (25 patients with severe disease and 21 patients with mild disease) were finally included. In our study, 45 patients were tested for serum HFABP from the day of admission to the 5th day of admission, and one patient was tested for serum HFABP on the 6th day of admission. In addition, 2 criti- cally severe COVID-19 patients died during hospitalization. Three COVID-19 patients with serum HFABP-positive result changed from mild to severe state during hospitalization. Demo- graphic and disease characteristics of 15 patients with serum HFABP-positive COVID-19 and 30 patients with serum HFABP- negative COVID-19 are presented in Table 1. The results of HFABP analysis showed a normal distribution, with values decreasing from 1.76 ng/mL to 24.68 ng/mL (mean 6.81, 95% CI 5.23–8.40, SD 5.33). Statistical analyses Categorical data were expressed as counts and percentages. Continuous data for normal and skew distribution are expressed as mean standard deviation and median, respectively. The Kol- mogorov Smirnov test was used to test the normality of the data distribution. Categorical vari- ables are expressed as numbers (%) and compared between the HFABP-raised group and the normal group by the Chi2 test or the Fisher’s exact test, and classification clinical, characteris- tics, and outcome rates were tested using the Chi2 test. A P value of less than 0.05 was considered statistically significant. Statistical analysis was performed using SPSS software(version 23, IBM Inc., Armonk, NY, USA). Outcomes Table 2 summarizes the relationship between positive HFABP and severe COVID-19. In the HFABP positive group, a significant increase in the prevalence of severe illness was observed during hospitalization of patients with COVID-19 (87.5% vs 40%, P = 0.002). Among them, in the HFABP positive group, 3 of 5 patients with mild COVID-19 worsened to severe COVID- 19 during hospitalization, and the incidence was 60%. One patient died in each of the two groups (P > 0.05), which was not statistically significant (Table 2). 3 / 7 PLOS ONE | https://doi.org/10.1371/journal.pone.0231687 April 29, 2020 PLOS ONE Correlation between Heart fatty acid binding protein and severe COVID-19: A case-control study Table 1. Demographic and disease characteristics of enrolled patients. Characteristic Group; no. (%) of patients All n = 45 HFABP Positive n = 15 HFABP negative n = 30 Male 25 5 22 Age, mean (SD), yr 52.4 65.3(17.9) 45.6(12.5) Tobacco smoking 3 0(0) 3(9.6) Car T 39 3(7.6) 2(5.1) Any comorbidity Diabetes 7 2(14.2) 5(16.1) Hypertension 4 1(7.1) 3(9.6) Cardiovascular disease 2 1(7.1) 1(3.2) Malignancy 3 1(7.1) 2(6.4) COPD 2 0(0) 2(6.4) CLD 0 0(0) 0(0) CKD 0 0(0) 0(0) Chronic obstructive pulmonary disease = COPD, Chronic liver disease = CLD, Chronic kidney disease = CKD, Cardiac troponin T = Ca T. Note: All differences were statistically nonsignificant. SD = standard deviation. Except as indicated for Age. https://doi.org/10.1371/journal.pone.0231687.t001 Table 1. Demographic and disease characteristics of enrolled patients. PLOS ONE | https://doi.org/10.1371/journal.pone.0231687 April 29, 2020 hronic obstructive pulmonary disease = COPD, Chronic liver disease = CLD, Chronic kidney disease = CKD, Discussion Both SARS-CoV and MERS-CoV are thought to originate in bats, and many studies have found coronaviruses with many other genomic sequences in bats. In 2013, Ge and colleagues reported the genome-wide sequence of a new coronavirus similar to SARS in bats. This virus can utilize human receptors and has the potential to replicate in human cells. 2019-nCoV has the potential to cause a pandemic, and it is still being studied in depth to prevent it from becoming a global health threat. Reliable and rapid differential diagnosis and reasonable treat- ment of diagnosed patients with COVID-19 are still essential to control the epidemic [15,16]. Our study screened 46 laboratory-confirmed patients with COVID-19. The patient was severe viral pneumonia and was fatal. All patients were sent to Chongqing Three Gorges Central Hos- pital before February 22, 2020, and their clinical symptoms were very similar to SARS. Acute respiratory distress syndrome (ARDS) can occur in severe patients, and they will require admission to the Intensive Care Unit and assistant treatment with mechanical ventilation. During the retrospective study, 2 of 46 patients included in this research died (4.3%); thus, the mortality of COVID-19 was very high. At present, the determination of severe COVID-19 is mainly based on the comprehensive analysis of clinical symptoms, signs, and blood gas analysis results. The global judgment of the severity of COVID-19 is based on the Chinese guidelines, and there is no clinical serum marker for comprehensive judgment. This study shows that in patients with COVID-19, Table 2. Clinical outcomes of the matched study population of COVID-19 with HFABP levels. Clinical outcomes HFABP Positive group N = 15 HFABP Negative group N = 30 P value Severe COVID-19 13 12 0.002 Mild-to-severe COVID-19 0 3 / Death 1 1 >0.05 Heart fatty acid-binding protein = HFABP. https://doi.org/10.1371/journal.pone.0231687.t002 Table 2. Clinical outcomes of the matched study population of COVID-19 with HFABP levels. 4 / 7 PLOS ONE | https://doi.org/10.1371/journal.pone.0231687 April 29, 2020 PLOS ONE Correlation between Heart fatty acid binding protein and severe COVID-19: A case-control study elevated serum HFABP is closely related to the severity of disease in the patients, and there is a significant statistical difference from patients with normal serum HFABP. Therefore, elevated serum HFABP can be used as an indicator of severe COVID-19 and an independent risk factor for patient prognosis. Discussion Among the patients in this study, 40 patients were monitored for tropo- nin T, and only 6 patients were positive for troponin T; however, there was no statistical differ- ence between the serum HFABP-negative and HFABP-positive groups. The hypothesis that HFABP is affected by troponin T does not hold, and the serum HFABP levels show an inde- pendent stable performance. This can happen because, like SARS-CoV and MERS-CoV, novel coronavirus infections also induce the secretion of a large number of cytokines [17–21], lead- ing to inflammatory lung injury, which reduces blood oxygen concentration and puts myocar- dial cells in a hypoxic state, thereby increasing the release of HFABP into the blood. We noted that 86.7% of patients with elevated serum HFABP are patients with severe COVID-19; there- fore, it is of great significance to judge and predict the outcome of patients with severe COVID-19. At present, there is no objective laboratory index for assessing the outcome of patients with COVID-19. Serum HFABP can be used as an effective index; thus, it can guide the clinicians to judge patients with severe COVID-19 in the short term, and elevated HFABP can also severely affect the outcome of patients with COVID-19. We also observed a phenomenon in which five patients with mild COVID-19 were positive for serum HFABP upon admission. Three patients deteriorated to severe neo-coronavirus pneumonia very quickly after admission, and the incidence of this event was 60%. However, 30 patients with mild COVID-19 were negative for serum HFABP, and none of these patients developed severe disease. Therefore, we speculate that if patients with mild COVID-19 are pos- itive for serum HFABP, they can easily deteriorate to severe COVID-19. Based on the small sample size of our screened cases, we did not perform a statistically significant difference analysis. In addition, two deaths were reported in our study, and they were severe COVID-19 patients. There was one case in the HFABP positive group, and the other case was in the HFABP negative group. We performed a statistical analysis for these groups, and there was no statistical difference in mortality between the two groups. However, we avoided sensitivity and specificity analysis because the sample size was small and we could not draw convincing con- clusions. A larger sample size is needed for further confirmation. Conclusion Our conclusion is that the elevation of HFABP is closely related to the severity of COVID-19 in the patients, and the elevated HFABP may cause rapid development of patients with mild COVID-19 into severe COVID-19. But serum HFABP negative maybe make patients with mild COVID-19 safer, the current data show no effect on the all-cause mortality. New corona- viruses have acquired effective human transmission capabilities [17,22]. We are deeply aware of the challenges and concerns that our global medical care encounters with COVID-19. Every effort should be made to study and control this disease. Therefore, we recommend worldwide promotion of HFABP application, which will help to judge and predict severe COVID-19. Supporting information S1 Data. (XLSX) S2 Data. (XLSX) 5 / 7 PLOS ONE | https://doi.org/10.1371/journal.pone.0231687 April 29, 2020 PLOS ONE Correlation between Heart fatty acid binding protein and severe COVID-19: A case-control study Author Contributions Conceptualization: Li Yin, Jiang Shao, Ye Zhu, Hailong Wang. Conceptualization: Li Yin, Jiang Shao, Ye Zhu, Hailong Wang. Data curation: Li Yin, Jiang Shao, Hailong Wang. Formal analysis: Li Yin, Huaming Mou, Ye Zhu, Jianming Zhang, Wei Shi, Shimei Yu, Hai- long Wang. Formal analysis: Li Yin, Huaming Mou, Ye Zhu, Jianming Zhang, Wei Shi, Shimei Yu, Hai- long Wang. Funding acquisition: Li Yin, Hailong Wang. Funding acquisition: Li Yin, Hailong Wang. Investigation: Xiaohua Pang, Jianjun Yang, Jianming Zhang. Methodology: Li Yin, Huaming Mou, Jiang Shao, Ye Zhu, Hailong Wang. Project administration: Li Yin, Hailong Wang. Resources: Huaming Mou. Software: Jianming Zhang. Supervision: Jiang Shao. Supervision: Jiang Shao. Validation: Huaming Mou. Visualization: Jianming Zhang, Wei Shi, Shimei Yu. Visualization: Jianming Zhang, Wei Shi, Shimei Yu. Writing – original draft: Li Yin, Huaming Mou, Jiang Shao, Hailong Wang. Writing – review & editing: Li Yin, Huaming Mou, Jiang Shao, Ye Zhu, Xiaohua Pang, Jian- jun Yang, Jianming Zhang, Wei Shi, Shimei Yu, Hailong Wang. Acknowledgments We thank LetPub (www.letpub.com) for its linguistic assistance during the preparation of this manuscript. References 1. Richman DD, Whitley RJ, Hayden FG, eds. Clinical virology, 4th edn. Washington: ASM Press, 2016. 2. Ksiazek TG, Erdman D, Goldsmith CS, Zaki SR, Peret T, Emery S, et al. A novel coronavirus associ- ated with severe acute respiratory syndrome. N Engl J Med 2003; 348: 1953–66. https://doi.org/10. 1056/NEJMoa030781 PMID: 12690092 3. Kuiken T, Fouchier RAM, Schutten M, Rimmelzwaan GF, Amerongen G, Riel D, et al. Newly discovered coronavirus as the primary cause of severe acute respiratory syndrome. Lancet 2003; 362: 263–70. https://doi.org/10.1016/S0140-6736(03)13967-0 PMID: 12892955 4. Drosten C, Gu¨nther S, Preiser W, Werf S, Brodt BR, Becker S, et al. Identification of a novel coronavirus in patients with severe acute respiratory syndrome. N Engl J Med 2003; 348: 1967–76. https://doi.org/ 10.1056/NEJMoa030747 PMID: 12690091 5. de Groot RJ, Baker SC, Baric RS, Brown CS, Drosten C, Enjuanes L, et al. Middle East respiratory syn- drome coronavirus (MERS-CoV): announcement of the Coronavirus Study Group. J Virol 2013; 87: 7790–92. https://doi.org/10.1128/JVI.01244-13 PMID: 23678167 6. Zaki AM, van Boheemen S, Bestebroer TM, Osterhaus ADME, Fouchierr RAM. Isolation of a novel coronavirus from a man with pneumonia in Saudi Arabia. N Engl J Med 2012; 367: 1814–20. https:// doi.org/10.1056/NEJMoa1211721 PMID: 23075143 7. WHO. Novel coronavirus Thailand (ex-China). Geneva: World Health Organization, Jan 14, 2020. https://www.who.int/csr/don/14-january-2020-novel-coronavirus-thailand/en/ (accessed Jan 23, 2020). 8. WHO. Novel Coronavirus Japan (ex-China). Geneva: World Health Organization, Jan 16, 2020. https://www.who.int/csr/don/16-january-2020-novel-coronavirus-japan-ex-china/en/ (accessed Jan 23, 2020). 6 / 7 PLOS ONE | https://doi.org/10.1371/journal.pone.0231687 April 29, 2020 PLOS ONE Correlation between Heart fatty acid binding protein and severe COVID-19: A case-control study 9. China National Health Commission. Update on the novel coronavirus pneumonia outbreak (Jan 24, 2020). Beijing: China National Health Commission, 2020. http://www.nhc.gov.cn/xcs/yqfkdt/202001/ c5da49c4c5bf4bcfb320ec2036480627.shtml (accessed Jan 24, 2020). 10. WHO. Novel coronavirus Republic of Korea (ex-China). Geneva: World Health Organization, 2020. https://www.who.int/csr/don/21-january-2020-novel-coronavirus-republic-of-korea-ex-china/en/ (accessed Jan 24, 2020). 11. US Centers for Disease Control and Prevention. First travel-related case of 2019 novel coronavirus detected in United States. Atlanta, GA: US Centers for Disease Control and Prevention, 2020. https:// www.cdc.gov/media/ releases/2020/p0121-novel-coronavirus-travel-case.html (accessed Jan 24, 2020). 12. Glatz JF, Kleine AH, van Nieuwenhoven FA, Hermens WT, van Dieijen-Visser MP, van der Vusse GJ. Fatty-acid-binding protein as a plasma marker for the estimation of myocardial infarct size in humans. British Heart Journal 1994; 71 (2): 135–40. https://doi.org/10.1136/hrt.71.2.135 PMID: 8130020 13. Kleine AH, Glatz JF, Van Nieuwenhoven FA, Van der Vusse GJ. PLOS ONE | https://doi.org/10.1371/journal.pone.0231687 April 29, 2020 References Release of heart fatty acid-binding pro- tein into plasma after acute myocardial infarction in man. Molecular and Cellular Biochemistry 1992; 116 (1–2): 155–62. https://doi.org/10.1007/bf01270583 PMID: 1480144 14. Hai-Long W, Xiao-Hua P, Jian-Jun Y. The Prognostic Value of Heart-Type Fatty Acid Binding Protein in Patients with Acute Coronary Syndrome. J Coll Physicians Surg Pak. 2018 Jan; 28(1):56–60. https:// doi.org/10.29271/jcpsp.2018.01.56 PMID: 29290194 15. Ge X-Y, Li J-L, Yang X-L, Chmura AA, Zhu G-J, Epstein JH, et al. Isolation and characterization of a bat SARS-like coronavirus that uses the ACE2 receptor. Nature 2013; 503: 535–38. https://doi.org/10. 1038/nature12711 PMID: 24172901 16. Wang M, Hu Z. Bats as animal reservoirs for the SARS coronavirus: hypothesis proved after 10 years of virus hunting. Virol Sin 2013; 28: 315–17. https://doi.org/10.1007/s12250-013-3402-x PMID: 24174406 17. Wong CK, Lam CWK, Wu AKL, Lp W K, Lee NLS, Chan IHS, et al. Plasma inflammatory cytokines and chemokines in severe acute respiratory syndrome. Clin Exp Immunol 2004; 136: 95–103. https://doi. org/10.1111/j.1365-2249.2004.02415.x PMID: 15030519 18. Mahallawi WH, Khabour OF, Zhang Q, Makhdoum HM, Suliman BA. MERS-CoV infection in humans is associated with a pro-inflammatory Th1 and Th17 cytokine profile. Cytokine 2018; 104: 8–13. https:// doi.org/10.1016/j.cyto.2018.01.025 PMID: 29414327 19. He L, Ding Y, Zhang Q, Che X, He Y, Shen H, et al. Expression of elevated levels of pro-inflammatory cytokines in SARS-CoV-infected ACE2+ cells in SARS patients: relation to the acute lung injury and pathogenesis of SARS. J Pathol 2006; 210: 288–97. https://doi.org/10.1002/path.2067 PMID: 17031779 20. Faure E, Poissy J, Goffard A, Fournier C, Kipnis E, Titecat M, et al. Distinct immune response in two MERS-CoV-infected patients: can we go from bench to bedside? PLoS One 2014; 9: e88716. https:// doi.org/10.1371/journal.pone.0088716 PMID: 24551142 21. Falzarano D, de Wit E, Rasmussen AL, Feldmann F, Feldmann H. Treatment with interferon-α2b and ribavirin improves outcome in MERS-CoVinfected rhesus macaques. Nat Med 2013; 19: 1313–17. https://doi.org/10.1038/nm.3362 PMID: 24013700 22. Assiri A, Al-Tawfiq JA, Al-Rabeeah AA, Al-Rabiah FA, Al-Hajjar S, Al-Barrak A, et al. Epidemiological, demographic, and clinical characteristics of 47 cases of Middle East respiratory syndrome coronavirus disease from Saudi Arabia: a descriptive study. Lancet Infect Dis 2013; 13: 752–61. https://doi.org/10. 1016/S1473-3099(13)70204-4 PMID: 23891402 7 / 7
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ENERGETICS ENERGETICS DOI 10.51582/interconf.19-20.06.2023.028 Моделювання аеродинаміки турбулізаторів теплообмінних елементів Денисенко Олександр Іванович1, Савранська Алла Володимирівна2 1 кандидат технічних наук, доцент, доцент кафедри системного аналізу та обчислювальної математики; Національний університет «Запорізька політехніка»; Украї 2 кандидат фізико-математичних наук, доцент, доцент кафедри системного аналізу та обчислювальної математики; Національний університет «Запорізька політехніка»; Україна 2 кандидат фізико-математичних наук, доцент, доцент кафедри системного аналізу та обчислювальної математики; Національний університет «Запорізька політехніка»; Україна 2 кандидат фізико-математичних наук, доцент, доцент кафедри системного аналізу та обчислювальної математики; Національний університет «Запорізька політехніка»; Україна ENERGETICS Proceedings of the 4th International Scientific and Practical Conference «Concepts for the Development of Society’s Scientific Potential» (June 19-20, 2023). Prague, Czech Republic No 159 ENERGETICS Proceedings of the 4th International Scientific and Practical Conference «Concepts for the Development of Society’s Scientific Potential» (June 19-20, 2023). Prague, Czech Republic No 159 Proceedings of the 4th International Scientific and Practical Conference «Concepts for the Development of Society’s Scientific Potential» (June 19-20, 2023). Prague, Czech Republic Анотація. Анотація. За допомогою програмного комплексу COMSOL Multiphisics, використовуючи метод скінчених елементів проведено 3-D моделювання аеродинаміки турбулізаторів циліндричних теплообмінників різної геометрії. Отримана візуалізація структури потоків газоповітряної суміші. Проведено серію чисельних експериментів для різних геометричних параметрів та фізичних умов. Ключові слова: тубулізатори 3-D моделювання теплообмінники This work is distributed under the terms of the Creative Commons Attribution-ShareAlike 4.0 International License (https://creativecommons.org/licenses/by-sa/4.0/). 286 ENERGETICS Proceedings of the 4th International Scientific and Practical Conference «Concepts for the Development of Society’s Scientific Potential» (June 19-20, 2023). Prague, Czech Republic No 159 Proceedings of the 4th International Scientific and Practical Conference «Concepts for the Development of Society’s Scientific Potential» Proceedings of the 4th International Scientific and Practical Conference «Concepts for the Development of Society’s Scientific Potential» (June 19-20, 2023). Prague, Czech Republic 287 This work is distributed under the terms of the Creative Commons Attribution-ShareAlike 4.0 International License (https://creativecommons.org/licenses/by-sa/4.0/). This work is distributed under the terms of the Creative Commons Attribution-ShareAlike 4.0 International License (https://creativecommons.org/licenses/by-sa/4.0/). This work is distributed under the terms of the Creative Commons Attribution-ShareAlike 4.0 International License ENERGETICS Проблема ефективного використання енергоресурсів останнім часом набула особливої актуальності. Коефіцієнт корисної дії опалювального обладнання в значній мірі залежить від конструктивних особливостей опалювальних котлів та теплообмінних елементів. З метою інтенсифікації теплообміну в опалювальних пристроях використовують турбулізатори різної геометрії [1-2]. Зазвичай, теплообмінні елементи у таких пристроях мають призматичну або циліндричну форму з вбудованими турбулізаторами у вигляді скрученої стрічки, або зигзагоподібного каналу, або іншої, більш складної геометрії. В роботі досліджуються аеродинамічні характеристики конструкцій теплообмінників у вигляді циліндричних патрубків з вбудованими турбулізаторами різної геометрії (рис.1). а) б) в) г) д) Рисунок 1. Турбулізатори з різною геометрією: а) скручена стрічка; б) подвійна скручена стрічка; в) потрійна скручена стрічка; г) стрічка зі змінним кроком закрутки; д) фрагментована стрічка з різноспрямованою закруткою д) г) б) а) в) Рисунок в) Рисунок д) г) б) а) Рисунок у 1. Турбулізатори з різною геометрією: а) скручена стрічка; б) подвійна скручена стрічка; в) потрійна скручена стрічка; г) стрічка зі змінним кроком закрутки; д) фрагментована стрічка з різноспрямованою закруткою у 1. Турбулізатори з різною геометрією: а) скручена стрічка; б) подвійна скручена стрічка; в) потрійна скручена стрічка; г) стрічка зі змінним кроком закрутки; д) фрагментована стрічка з різноспрямованою закруткою у 1. Турбулізатори з різною геометрією: а) скручена стрічка; б) подвійна скручена стрічка; в) потрійна скручена стрічка; г) стрічка зі змінним кроком закрутки; д) фрагментована стрічка з різноспрямованою закруткою Процес теплообміну відбувається в результаті проходження гарячої газоповітряної суміші через теплообмінник, який омивається зовні рідинним теплоносієм. Проведення натурних експериментів для дослідження таких 287 This work is distributed under the terms of the Creative Commons Attribution-ShareAlike 4.0 International License (https://creativecommons.org/licenses/by-sa/4.0/). 287 ENERGETICS Proceedings of the 4th International Scientific and Practical Conference «Concepts for the Development of Society’s Scientific Potential» (June 19-20, 2023). Prague, Czech Republic No 159 Proceedings of the 4th International Scientific and Practical Conference «Concepts for the Development of Society’s Scientific Potential» (June 19-20, 2023). Prague, Czech Republic Proceedings of the 4th International Scientific and Practical Conference «Concepts for the Development of Society’s Scientific Potential» Proceedings of the 4th International Scientific and Practical Conference «Concepts for the Development of Society’s Scientific Potential» ENERGETICS пристроїв вимагає великих витрат, а використання спрощених балансових моделей дає досить наближені результати без можливості візуалізації складних аеродинамічних ефектів. Враховуючи складну геометрію розрахункової області, аналітичний розв’язок задачі неможливий. Тому, використання сучасних чисельних методів і алгоритмів є оптимальним шляхом для аналізу складних тривимірних моделей. пристроїв вимагає великих витрат, а використання спрощених балансових моделей дає досить наближені результати без можливості візуалізації складних аеродинамічних ефектів. Враховуючи складну геометрію розрахункової області, аналітичний розв’язок задачі неможливий. Тому, використання сучасних чисельних методів і алгоритмів є оптимальним шляхом для аналізу складних тривимірних моделей. В роботі досліджувались окремо тільки аеродинамічні характеристики турбулізаторів, тобто температурний фактор не враховувався. В якості математичної моделі використовувалась тривимірна система диференційних рівнянь Нав’є-Стокса. Розрахунки здійснювалися методом скінчених елементів за допомогою програмного комплексу COMSOL Multiphisics [3]. Геометрія розрахункової області та форми турбулізаторів будувались за допомогою внутрішніх інструментів COMSOL Multiphisics. COMSOL має змогу імпортувати геометричні об’єкти з інших програмних продуктів, а саме з AutoCAD, але в даному випадку достатньо вбудованих можливостей COMSOL. Всі фізичні характеристики обирались із вбудованої в COMSOL бібліотеки матеріалів. Розбивка розрахункової області на скінчені елементи також виконувалась вбудованими засобами. Поверхня турбулізатора визначалась параметричними рівняннями 𝑥= 𝑠1 cos 𝑠2 , 𝑦= 𝑠1 sin 𝑠2, 𝑧= ℎ( 𝑠2 𝜋𝑘𝑣) 𝑛 , (1) 𝑠1 ∈[−𝑟, 𝑟], 𝑠2 ∈[0, 𝜋𝑘𝑣], (1) де r - внутрішній радіус патрубка, h – висота патрубка, kv – кількість витків стрічки, n – параметр, який визначає щільність витків стрічки. де r - внутрішній радіус патрубка, h – висота патрубка, kv – кількість витків стрічки, n – параметр, який визначає щільність витків стрічки. Для n=1 будемо мати стрічку з рівномірним кроком закрутки, інші значення n створюють змінний рівень щільності закрутки по степеневому закону. Така параметризація дозволяє досить гнучко змінювати геометрію стрічки для нових чисельних експериментів. Проведено серію чисельних експериментів для різних геометричних параметрів турбулізаторів та властивостей газоповітряної суміші. Розглядались випадки граничних умов, This work is distributed under the terms of the Creative Commons Attribution-ShareAlike 4.0 International License (https://creativecommons.org/licenses/by-sa/4.0/). 288 ENERGETICS Proceedings of the 4th International Scientific and Practical Conference «Concepts for the Development of Society’s Scientific Potential» (June 19-20, 2023). Prague, Czech Republic No 159 Proceedings of the 4th International Scientific and Practical Conference «Concepts for the Development of Society’s Scientific Potential» (June 19-20, 2023). Prague, Czech Republic This work is distributed under the terms of the Creative Commons Attribution-ShareAlike 4.0 International License (https://creativecommons.org/licenses/by-sa/4.0/). ENERGETICS коли на границях патрубка задавався перепад тиску, а також випадки, коли на вході в патрубок задавалась швидкість газового потоку. На внутрішніх поверхнях патрубків та на стрічках задавались умови прилипання. коли на границях патрубка задавався перепад тиску, а також випадки, коли на вході в патрубок задавалась швидкість газового потоку. На внутрішніх поверхнях патрубків та на стрічках задавались умови прилипання. р д у р В наведених прикладах розрахунків для порівняння характеристик турбулізаторів з різною геометрією розглядались циліндричні теплообмінники однакової висоти h=0.3 м та однакових радіусів r=0.028м, перепад тиску на границях патрубків теж був фіксований ∆𝑃= 5Па. Кількість витків стрічок у всіх наведених прикладах теж однакова і дорівнює 5. На Рис 2 7 наведені деякі результати розрахунків В наведених прикладах розрахунків для порівняння характеристик турбулізаторів з різною геометрією розглядались циліндричні теплообмінники однакової висоти h=0.3 м та однакових радіусів r=0.028м, перепад тиску на границях патрубків теж був фіксований ∆𝑃= 5Па. Кількість витків стрічок у всіх наведених прикладах теж однакова і дорівнює 5. На Рис. 2 – 7 наведені деякі результати розрахунків. Рисунок 3 Ізобари в структурі потоку повітряної суміші Рисунок 2 Лінії току та розподіл швидкостей в поперечних перерізах теплообмінника з однією стрічкою Рисунок 3 Ізобари в структурі потоку повітряної суміші Рисунок 2 Лінії току та розподіл швидкостей в поперечних перерізах теплообмінника з однією стрічкою Рисунок 3 Ізобари в структурі потоку повітряної суміші Рисунок 3 Ізобари в структурі потоку повітряної суміші Рисунок 2 Лінії току та розподіл швидкостей в поперечних перерізах теплообмінника з однією стрічкою This work is distributed under the terms of the Creative Commons Attribution-ShareAlike 4.0 International License (https://creativecommons.org/licenses/by-sa/4.0/). 289 ENERGETICS Proceedings of the 4th International Scientific and Practical Conference «Concepts for the Development of Society’s Scientific Potential» (June 19-20, 2023). Prague, Czech Republic No 159 Proceedings of the 4th International Scientific and Practical Conference «Concepts for the Development of Society’s Scientific Potential» (June 19-20, 2023). Prague, Czech Republic (June 19-20, 2023). Prague, Czech Republic This work is distributed under the terms of the Creative Commons Attribution-ShareAlike 4.0 International License (https://creativecommons.org/licenses/by-sa/4.0/). This work is distributed under the terms of the Creative Commons Attribution-ShareAlike 4.0 International License (https://creativecommons.org/licenses/by-sa/4.0/). ENERGETICS Турбулізатори зі скручених стрічок з постійним кроком закрутки формують структуру потоку, де лінії току мають гвинтоподібну форму адаптовану до геометрії турбулізатора (Рис. 2-5). Як показали розрахунки, аеродинамічні характеристики пристроїв з подвійною і потрійною стрічкою мало чим відрізняться, тому немає потреби ускладнювати технологію виготовлення та використання багатострічкових турбулізаторів. Рисунок 4 Лінії току та розподіл швидкостей в поперечних перерізах теплообмінника з подвійною стрічкою Рисунок 5 Розподіл швидкостей в поперечних перерізах теплообмінника з потрійною стрічкою Турбулізатори зі змінним кроком закрутки (Рис. 6) дозволяють перерозподіляти теплове навантаження по довжині теплообмінника, збільшуючи турбулізацію потоку за рахунок Рисунок 4 Лінії току та розподіл швидкостей в поперечних перерізах теплообмінника з подвійною стрічкою Рисунок 5 Розподіл швидкостей в поперечних перерізах теплообмінника з потрійною стрічкою Рисунок 4 Лінії току та розподіл швидкостей в поперечних перерізах теплообмінника з подвійною стрічкою Турбулізатори зі змінним кроком закрутки (Рис. 6) дозволяють перерозподіляти теплове навантаження по довжині теплообмінника, збільшуючи турбулізацію потоку за рахунок 290 ENERGETICS Proceedings of the 4th International Scientific and Practical Conference «Concepts for the Development of Society’s Scientific Potential» (June 19-20, 2023). Prague, Czech Republic No 159 Proceedings of the 4th International Scientific and Practical Conference «Concepts for the Development of Society’s Scientific Potential» 291 This work is distributed under the terms of the Creative Commons Attribution-ShareAlike 4.0 International License (https://creativecommons.org/licenses/by-sa/4.0/). ENERGETICS Таблиця 1 Витратні характеристики турбулізаторів Тип конструкції турбулізатора а б в г д Витрати повітря (м3/с) 0,0019 0,00127 0,0011 0,00872 0,00154 Таблиця 1 Проведення чисельних експериментів дозволяє дослідити складну структуру та визначити витратні характеристики газових потоків. Відомо, що використання турбулізаторів підвищує ефективність теплообміу. З іншого боку, турбулізатори суттєво збільшують аеродинамічний опір газовому потоку. Оскільки в побутових системах опалення зазвичай використовують теплообмінники з вільною конвекцією, при проектуванні необхідно обирати такі геометричні параметри турбулізаторів, які б дозволяли в критичних умовах забезпечити повну евакуацію продуктів горіння. Для остаточного висновку щодо обрання оптимальної геометрії турбулізаторів необхідно вирішення спряженої задачі тепломасообміну, що також можливо за допомогою програмного комплексу COMSOL Multiphisics. Використання чисельного моделювання дозволяє на стадії проектування прогнозувати поведінку теплообмінників в різних фізичних умовах та для різних геометричних параметрів, що надає можливість заощадити на проведенні коштовних натурних експериментів. This work is distributed under the terms of the Creative Commons Attribution-ShareAlike 4.0 International License (https://creativecommons.org/licenses/by-sa/4.0/). ENERGETICS підвищення щільності закрутки в зонах з невеликими температурними градієнтами і зменшуючи щільність закрутки в зонах з великими температурними градієнтами. Як показали розрахунки, в порівнянні з іншими конструкціями такий тип турбулізатора має найбільший аеродинамічний опір Турбулізатори з різноспрямованою закруткою (Рис. 7) в порівняні з попередніми більш інтенсивно перемішують газовий потік, що має позитивний вплив на інтенсифікацію теплообміну. Технологія виготовлення таких турбулізаторів також ускладнена. Рисунок 6 Розподіл швидкостей в поперечних перерізах теплообмінника зі стрічкою з нерівномірним кроком закрутки Рисунок 7 Лінії току та розподіл швидкостей в поперечних перерізах теплообмінника зі стрічкою з різноспрямованою закруткою В Таблиці 1 наведені витратні характеристики розглянутих конструкцій. Рисунок 7 Лінії току та розподіл швидкостей в поперечних перерізах теплообмінника зі стрічкою з різноспрямованою закруткою Рисунок 6 Розподіл швидкостей в поперечних перерізах теплообмінника зі стрічкою з нерівномірним кроком закрутки Рисунок 7 Лінії току та розподіл швидкостей в поперечних перерізах теплообмінника зі стрічкою з різноспрямованою закруткою і Рисунок 6 Розподіл швидкостей в поперечних перерізах теплообмінника зі стрічкою з нерівномірним кроком закрутки Рисунок 7 Лінії току та розподіл швидкостей в поперечних перерізах теплообмінника зі стрічкою з різноспрямованою закруткою В Таблиці 1 наведені витратні характеристики розглянутих конструкцій. В Таблиці 1 наведені витратні характеристики розглянутих конструкцій. 291 ENERGETICS Proceedings of the 4th International Scientific and Practical Conference «Concepts for the Development of Society’s Scientific Potential» (June 19-20, 2023). Prague, Czech Republic No 159 Proceedings of the 4th International Scientific and Practical Conference «Concepts for the Development of Society’s Scientific Potential» (June 19-20, 2023). Prague, Czech Republic References: [1] Денисенко А.И., Пархоменко Л.А. 3D-моделирование закрученных потоков в трубах с ленточными винтообразными вставками/ А.И Денисенко., Л.А. Пархоменко // TENDENZE ATTUALI DELLA MODERNA RICERCA SCIENTIFICA: der Sammlung wissenschaftlicher Arbeiten «ΛΌГOΣ» zu den Materialien der internationalen wissenschaftlich-praktischen Konferenz (B. 3), 5. Juni, 2020. Stuttgart, Deutschland: Europäische Wissenschaftsplattform. – р.63-65. [2] Goodarzi, K., Goudarzi, S.Y., Zendehbudi G. (2015). Investigation of the effect of using tube inserts for the intensification of heat transfer. Thermal Engineering, 62(1), 68–75. [3] Математическое моделирование физико-химических процессов в среде COMSOL Multiphysics 5.2 [Текст]: учебное пособие /Коваленко А.В., Узденова А.М., Уртенов М.X. и др. – С-Петербург. : Лань, Планета музыки, 2017– 238 с. 292
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Promising Approaches to Optimize the Biological Properties of the Antimicrobial Peptide Esculentin-1a(1–21)NH2: Amino Acids Substitution and Conjugation to Nanoparticles
Frontiers in chemistry
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Citation: Casciaro B, Cappiello F, Cacciafesta M and Mangoni ML (2017) Promising Approaches to Optimize the Biological Properties of the Antimicrobial Peptide Esculentin-1a(1–21)NH2: Amino Acids Substitution and Conjugation to Nanoparticles. Front. Chem. 5:26. doi: 10.3389/fchem.2017.00026 Promising Approaches to Optimize the Biological Properties of the Antimicrobial Peptide Esculentin-1a(1–21)NH2: Amino Acids Substitution and Conjugation to Nanoparticles Bruno Casciaro 1, Floriana Cappiello 1, Mauro Cacciafesta 2 and Maria Luisa Mangoni 1* 1 Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, Rome, Italy, 2 Department of Cardiovascular, Respiratory, Nephrological, Anesthesiological and Geriatric Sciences, Sapienza University of Rome, Rome, Italy Antimicrobial peptides (AMPs) represent an interesting class of molecules with expanding biological properties which make them a viable alternative for the development of future antibiotic drugs. However, for this purpose, some limitations must be overcome: (i) the poor biostability due to enzymatic degradation; (ii) the cytotoxicity at concentrations slightly higher than the therapeutic dosages; and (iii) the inefficient delivery to the target site at effective concentrations. Recently, a derivative of the frog skin AMP esculentin-1a, named esculentin-1a(1–21)NH2, [Esc(1–21): GIFSKLAGKKIKNLLISGLKG-NH2] has been found to have a potent activity against the Gram-negative bacterium Pseudomonas aeruginosa; a slightly weaker activity against Gram-positive bacteria and interesting immunomodulatory properties. With the aim to optimize the antimicrobial features of Esc(1–21) and to circumvent the limitations described above, two different approaches were followed: (i) substitutions by non-coded amino acids, i.e., α-aminoisobutyric acid or D-amino acids; and (ii) peptide conjugation to gold nanoparticles. In this mini-review, we summarized the structural and functional properties of the resulting Esc(1–21)-derived compounds. Overall, our data may assist researchers in the rational design and optimization of AMPs for the development of future drugs to fight the worldwide problem of antibiotic resistance. MINI REVIEW MINI REVIEW published: 25 April 2017 doi: 10.3389/fchem.2017.00026 Edited by: John D. Wade, Florey Institute of Neuroscience and Mental Health, Australia Reviewed by: Predrag Cudic, Florida Atlantic University, USA Daniel Knappe, Leipzig University, Germany *Correspondence: Maria Luisa Mangoni marialuisa.mangoni@uniroma1.it Specialty section: This article was submitted to Chemical Biology, a section of the journal Frontiers in Chemistry Received: 30 January 2017 Accepted: 05 April 2017 Published: 25 April 2017 Keywords: antimicrobial peptide, frog-skin, antibiotic-resistance, D-amino acids, gold nanoparticles, Pseudomonas aeruginosa Esculentin-1a(1–21)NH2: Synthesis and Characterization All members of the esculentin-1 family have a primary structure composed of 46 amino acids and contain a C-terminal hepta- membered ring stabilized by a disulfide bridge (Mangoni et al., 2015). They adopt an amphipathic α-helix structure in membrane mimicking environments and have a net charge of +5 at neutral pH (Wang et al., 2016). AMPs belonging to the esculentin-1 family were initially isolated and purified by reverse- phase high performance liquid chromatography (RP-HPLC) from the cutaneous secretions of Pelophylax lessonae/ridibundus (previously classified as Rana esculenta) specimen (Simmaco et al., 1993). They have a highly conserved C-terminal half and differ by only one or two residues in the N-terminal region (Simmaco et al., 1994). Interestingly, a fragment corresponding to the 19–46 portion of esculentin-1 peptides was isolated from one of the HPLC fractions but it was devoid of antimicrobial activity, probably due to its low net positive charge (+1 vs. +5 of the full-length AMP, Simmaco et al., 1994). It was then investigated whether the antimicrobial activity was retained in the N-terminal half of the molecule. For this reason, a peptide corresponding to the 1–18 fragment of esculentin-1b was chemically synthesized and amidated at its C-terminus (Mangoni et al., 2003). Note that the C-terminal amidation is a common post-translational modification in linear AMPs from frog skin (Nicolas and El Amri, 2009). This peptide, named Esc(1–18), had a comparable antimicrobial activity to that of the full-length parent esculentin-1, but a lower hemolytic capacity (Mangoni et al., 2003). Structurally, Esc(1–18) was found to adopt an α-helix structure in lipid vesicles mimicking the anionic character of microbial membranes (Mangoni et al., 2003). It rapidly killed bacteria (e.g., Escherichia coli) within 15–20 min with concomitant leakage of cytosolic material, presumably due to the formation of transient membrane-breakages (Marcellini et al., 2009). Since the minimum length for a peptide in α-helix conformation to span a phospholipid bilayer (∼30 Å thick) is about 20 amino acids, a longer analog named esculentin-1a(1– 21)NH2, Esc(1–21), was further synthesized and characterized for its biological properties. Esc(1–21) shares the first 20 residues with esculentin-1a (Figure 1) followed by an amidated ANTIMICROBIAL PEPTIDES: GENERAL FEATURES Peptide-membrane interaction is the most important step controlling the selectivity of AMPs toward microbial membranes, which are much richer in anionic phospholipids compared to those of mammalian cells mainly made of electrically-neutral (zwitterionic) lipids (Oren et al., 1999). However, peptide- membrane interaction is dictated not only by the peptide’s cationicity, but also by other physiochemical parameters of AMPs encompassing their length, hydrophobicity, amphipathicity, and helicity (Marín-Medina et al., 2016). Remarkably, unlike conventional antibiotics, this non-specific mechanism of action of AMPs very rarely induces resistance (Bechinger and Gorr, 2017) and makes them an interesting class of molecules for the development of new antimicrobial compounds (Mazer- Amirshahi et al., 2016). To date, thousands of AMPs have been characterized from a variety of natural sources as well as their synthetic derivatives (Liu et al., 2016). Noteworthy, an increasing number of AMPs has already entered into advanced stages of clinical trials for topical treatment of different types of infections. Nevertheless, several limitations can hinder their development as new therapeutics (da Cunha et al., 2017). Among them: (i) the cytotoxicity at concentrations slightly higher than antimicrobial dosing; (ii) the low peptide biostability due to fast proteolytic degradation; and (iii) the inefficient delivery to the target site at effective concentrations (Fjell et al., 2012). Nowadays, thanks to the progress in computational studies and nanotechnologies, it is possible to circumvent these issues. In this mini-review article, after a brief overview on amphibian AMPs and the structural/functional relationships of the frog skin-derived AMP esculentin-1a(1–21)NH2, Esc(1–21), we will mainly focus on the principal approaches that have been used to optimize the biological properties of Esc(1–21): (i) substitution by non-coded amino acids and (ii) conjugation to inorganic nanoparticles. ANTIMICROBIAL PEPTIDES: GENERAL FEATURES Gene-encoded antimicrobial peptides (AMPs) are evolutionally conserved molecules produced by almost all living organisms (e.g., bacteria, fungi, higher eukaryotes including humans, Ageitos et al., 2016). As part of key effectors of the innate immunity, they act as a sudden response against a multitude of microorganisms before the adaptive immune system comes into action (Boman, 1995; Hemshekhar et al., 2016). Despite their different length and secondary structure ranging from an April 2017 | Volume 5 | Article 26 Frontiers in Chemistry | www.frontiersin.org Amino Acids Substitution and Gold-Nanoparticles Casciaro et al. α-helix, a β-strand, a loop, or an extended conformation in hydrophobic environments, most of them share an amphipathic and cationic character at neutral pH (Powers and Hancock, 2003). These two properties are crucial factors, especially for the mechanism of action of α-helical AMPs, which is generally based on the perturbation of the target microbial membrane (Bechinger and Gorr, 2017). More specifically, it consists in an initial electrostatic interaction between the positively- charged AMP and the negatively-charged components of the microbial cell surface, such as lipoteichoic acids in Gram-positive bacteria, or lipopolysaccharides (LPS) in Gram-negatives, to finally reach the plasma-membrane. This is then destabilized by pores formation/local cracks or disintegration in a detergent- like manner, with consequent cell death (Hall and Aguilar, 2010). Peptide-membrane interaction is the most important step controlling the selectivity of AMPs toward microbial membranes, which are much richer in anionic phospholipids compared to those of mammalian cells mainly made of electrically-neutral (zwitterionic) lipids (Oren et al., 1999). However, peptide- membrane interaction is dictated not only by the peptide’s cationicity, but also by other physiochemical parameters of AMPs encompassing their length, hydrophobicity, amphipathicity, and helicity (Marín-Medina et al., 2016). Remarkably, unlike conventional antibiotics, this non-specific mechanism of action of AMPs very rarely induces resistance (Bechinger and Gorr, 2017) and makes them an interesting class of molecules for the development of new antimicrobial compounds (Mazer- Amirshahi et al., 2016). To date, thousands of AMPs have been characterized from a variety of natural sources as well as their synthetic derivatives (Liu et al., 2016). Noteworthy, an increasing number of AMPs has already entered into advanced stages of clinical trials for topical treatment of different types of infections. Nevertheless, several limitations can hinder their development as new therapeutics (da Cunha et al., 2017). ANTIMICROBIAL PEPTIDES: GENERAL FEATURES Among them: (i) the cytotoxicity at concentrations slightly higher than antimicrobial dosing; (ii) the low peptide biostability due to fast proteolytic degradation; and (iii) the inefficient delivery to the target site at effective concentrations (Fjell et al., 2012). Nowadays, thanks to the progress in computational studies and nanotechnologies, it is possible to circumvent these issues. In this mini-review article, after a brief overview on amphibian AMPs and the structural/functional relationships of the frog skin-derived AMP esculentin-1a(1–21)NH2, Esc(1–21), we will mainly focus on the principal approaches that have been used to optimize the biological properties of Esc(1–21): (i) substitution by non-coded amino acids and (ii) conjugation to inorganic nanoparticles. surface in a holocrine mechanism after stress or tissue injury (König et al., 2015). It was first discovered that amphibian AMPs do not only protect the host from invading microbial pathogens, but also regulate the animal’s natural flora (Simmaco et al., 1998); a trait which has then been confirmed also for human AMPs (Mangoni et al., 2016). Over the years, since the discovery of magainins from the skin of Xenopus laevis (Zasloff, 1987), an increasing number of AMPs has been identified from different Anuran species (Coccia et al., 2011; Conlon, 2011a). In particular, from various Rana genera, a large number of AMPs has been isolated and characterized. On the basis of their common structural features, they have been classified into several families encompassing brevinins-1, brevinins-2, nigrocins, temporins, esculentins-1, and esculentins-2 (Conlon et al., 2004). α helix, a β strand, a loop, or an extended conformation in hydrophobic environments, most of them share an amphipathic and cationic character at neutral pH (Powers and Hancock, 2003). These two properties are crucial factors, especially for the mechanism of action of α-helical AMPs, which is generally based on the perturbation of the target microbial membrane (Bechinger and Gorr, 2017). More specifically, it consists in an initial electrostatic interaction between the positively- charged AMP and the negatively-charged components of the microbial cell surface, such as lipoteichoic acids in Gram-positive bacteria, or lipopolysaccharides (LPS) in Gram-negatives, to finally reach the plasma-membrane. This is then destabilized by pores formation/local cracks or disintegration in a detergent- like manner, with consequent cell death (Hall and Aguilar, 2010). Frontiers in Chemistry | www.frontiersin.org AMPHIBIAN SKIN ANTIMICROBIAL PEPTIDES Among natural storehouses of AMPs, frog skin is one of the richest (Conlon, 2011b). The expression of genes encoding for these peptides in dermal serous glands is induced upon contact with microorganisms (Mangoni et al., 2001); and the produced AMPs are stored within granules that are released onto the skin Frontiers in Chemistry | www.frontiersin.org April 2017 | Volume 5 | Article 26 2 Casciaro et al. Amino Acids Substitution and Gold-Nanoparticles FIGURE 1 | Schematic representation of the amino acids substitutions used to design the Esc(1–21)-analogs and a representative image of the peptide-conjugated AuNPs. FIGURE 1 | Schematic representation of the amino acids substitutions used to design the Esc(1–21)-analogs and a representative image of the peptide-conjugated AuNPs. glycine (Islas-Rodrìguez et al., 2009). It differs from Esc(1– 18) for having (i) an Ile residue at position 11 instead of a Leu and (ii) three additional C-terminal residues (Leu-Lys-Gly) which confer it a higher net positive charge at neutral pH (+6). This should strengthen the electrostatic interaction of the peptide with the negatively-charged membrane of microbial cells. Indeed, Esc(1–21) exhibited a higher antimicrobial potency than Esc(1–18) (Mangoni et al., 2015), especially against Gram- negative bacteria, e.g., the opportunistic pathogen Pseudomonas aeruginosa (Gellatly and Hancock, 2013). Esc(1–21) displayed a quick bactericidal activity within 15 min against both reference and clinical isolates of P. aeruginosa with concentrations causing 99.9% killing between 0.5 and 1 µM in physiological solution (Luca et al., 2013). Differently, a weaker activity was detected against Gram-positive bacteria, as pointed out by the higher values of minimum inhibitory concentration (MIC) compared to those recorded toward Gram-negatives (Kolar et al., 2015). to increase the biostability of this peptide and to decrease its cytotoxicity without compromising its antimicrobial efficacy: modification of Esc(1–21) by non-coded amino acids i.e., α-aminoisobutyric acid (Aib) or D-amino acids, and (ii) its conjugation to gold nanoparticles (AuNPs). All these modifications are represented in Figure 1. The Analog [Aib1,10,18]-Esc(1–21) Aib-rich peptides, such as peptaibiotics, Aib residues are located either within the hydrophobic face or at its boundary with the hydrophilic one (Toniolo et al., 1994; De Zotti et al., 2012b). Aib-rich peptides, such as peptaibiotics, Aib residues are located either within the hydrophobic face or at its boundary with the hydrophilic one (Toniolo et al., 1994; De Zotti et al., 2012b). replacement of two L-amino acids with the corresponding D- enantiomers was carried out at position 14 and 17. Note that it was improbable that the C-terminal tail Gly18-Gly21 of Esc(1– 21) folded in a stable helical conformation. y p The secondary structure of both Esc(1–21) and its [Aib1,10,18]- Esc(1–21) was initially investigated by circular dichroism (CD) (Biondi et al., 2016) in water and two different membrane-mimicking environments e.g., sodium dodecyl sulfate (SDS) aqueous solution and trifluoroethanol (TFE). The results confirmed that both peptides adopted an unordered conformation in water and an α-helix structure in both SDS and TFE. However, at increasing concentration of TFE (from 20 to 50%) the helical content in [Aib1,10,18]-Esc(1–21) sharply increased with respect to the parent peptide. The helical and less flexible structure of [Aib1,10,18]-Esc(1–21) compared to Esc(1– 21) was also confirmed by 2D-NMR analysis in TFE solution (Biondi et al., 2016). The stability of both isomers was initially examined in the presence of 10 and 30% fresh human serum after 24 h incubation at 37◦C. The data revealed that in comparison with Esc(1–21) <50% of the diastereomer was degraded (Di Grazia et al., 2015a). Besides, the presence of these two D-amino acids made the peptide significantly more resistant to the proteolytic cleavage caused by both human and bacterial elastases (Cappiello et al., 2016). When the structure of the two peptides was analyzed by CD in lysophosphatidylcholine (LPC), which simulates the zwitterionic nature of mammalian cell membranes, a loss of α-helix structure was clearly detected for Esc(1–21)-1c (Di Grazia et al., 2015a). In contrast with data obtained for the Aib-analog, this diastereomer was significantly less toxic than Esc(1–21) against mammalian cells, either circulating cells (e.g., erythrocytes, macrophages) or epithelial cells. More precisely, its LD50 was higher than 256 µM in comparison with a LD50 ranging from 64 to 150 µM for the all- L peptide toward macrophages and epithelial cells, respectively (Di Grazia et al., 2015a; Cappiello et al., 2016). The Analog [Aib1,10,18]-Esc(1–21) Interestingly, the introduction of these two residues in the D-configuration also conferred the peptide: (i) a higher tendency than the all-L counterpart to kill P. aeruginosa biofilms at concentrations lower than 25 µM (despite the diastereomer had a slightly reduced bactericidal activity against the free-living form of this pathogen); and (ii) a higher “wound” healing activity in vitro (Di Grazia et al., 2015a). Overall, the greater stability and content of α-helix in the Aib-analog were found to influence the biological properties of the peptide. More precisely, the Aib-analog gained an overall higher activity against Gram-positive bacteria, especially those belonging to Staphylococcus genus [MIC of 2–4 vs. 16–64 µM of Esc(1–21)] without losing its efficacy against Gram-negative bacteria and Candida species (Biondi et al., 2016). It is possible that differences in the composition of the membrane or cell wall among these microorganisms account for the different activity of the two esc-peptides against them. However, a higher α-helicity in [Aib1,10,18]-Esc(1–21) resulted in increased cytotoxicity against mammalian cell lines (e.g., alveolar epithelial cells and keratinocytes). The experimental data showed that, at the antimicrobial concentrations, Esc(1–21) and [Aib1,10,18]-Esc(1–21) were harmless to human cells, while at higher concentrations the cytotoxic effect of the Aib-analog became clearly evident in comparison with the parent Esc(1– 21) (Biondi et al., 2016). This is consistent with the notion that both α-helix conformation and its stability are crucial parameters for mammalian membrane perturbation and cell lysis, likely assisting the peptide’s penetration into the hydrophobic core of phospholipids bilayers (Shai and Oren, 1996). AuNPs@Esc(1–21) Amino acids replacement is not the only strategy to increase the stability of a peptide to proteolytic degradation. Moreover, this approach does not allow a peptide to overcome biological barriers (e.g., mucus, skin layers) before reaching the site of infection at high active concentrations (d’Angelo et al., 2015). A different biochemical approach to also assist drug delivery at effective concentrations is given by its conjugation to nanoparticles (NPs). This would enable not only to protect the drug from the external environment but also to increase its local concentration. The Analog [Aib1,10,18]-Esc(1–21) The Analog [Aib1,10,18]-Esc(1–21) The Aib residue is a non-natural amino acid mainly used to increase the stability of α-helix conformation (Bellanda et al., 2001). Due to their strong helicogenicity (De Zotti et al., 2012a), when Aib residues are inserted into the primary structure of peptides, they are expected to increase their helical content and to protect them from proteolytic attack (Rink et al., 2010). The usage of Aib residues is also expected to enlarge the spectrum of activity of Esc(1–21). This is because a stabilized α-helix structure is reported to be correlated to the AMPs’ activity against Gram-positive bacteria (Giangaspero et al., 2001) toward which Esc(1–21) is not particularly active. The Aib-analog was synthesized by replacing three amino acids in positions 1, 10, and 18 with Aib residues (Figure 1). This replacement was rationally designed on the basis of the following considerations: (i) an Aib residue in position 1 should prevent enzymatic degradation by aminopeptidases, while the protection of the C-terminus from carboxypeptidases would not be necessary, due to the presence of an amidated glycine in Esc(1–21) (Rink et al., 2010); (ii) Aib residues in positions 10 and 18 should contribute to stabilize the α-helix structure, due to their stronger α-helix-promoting activity when placed internally to the primary structure of a peptide; (iii) according to an ideal α-helix folding of Esc(1–21), it was possible to identify an hydrophobic face and an hydrophilic one (Biondi et al., 2016). It is known that in naturally-occurring Among other interesting biological features, Esc(1–21) was found to have the ability (i) to hinder the secretion of the pro-inflammatory cytokine TNF-α from P. aeruginosa LPS- stimulated immune cells and (ii) to induce re-epithelialization of a pseudo-“wound” area generated in a monolayer of keratinocytes, the most abundant cells in epidermis (Haslam et al., 2014), at a faster rate than the mammalian AMP LL-37 (Di Grazia et al., 2015b). This is a relevant matter, which is not shown by any traditional antibiotic. Note that the healing of an injured infected tissue does not only require elimination of microbial pathogens but also the recovery of the tissue integrity along with its barrier function to prevent pathogens penetration. Nevertheless, Esc(1–21) is not free from the restrictions mentioned above. In the following sections, we summarize the outcome of two different rational approaches employed April 2017 | Volume 5 | Article 26 3 Amino Acids Substitution and Gold-Nanoparticles Casciaro et al. Frontiers in Chemistry | www.frontiersin.org FUNDING The work was supported by grants from Sapienza University of Rome (Ricerca Università 2016). Part of the work was also supported by FILAS Grant Prot. FILAS RU-2014-1020. CONCLUSIONS • Greater efficacy in promoting migration of human lung epithelial cells Antibiotic-resistant microbial infections cause thousands of deaths per year worldwide and this necessitates the discovery of new compounds to counter them. In this scenario, AMPs represent promising anti-infective molecules with expanding properties. However, their low biostability, cytotoxic effect at concentrations higher than therapeutic dosages and the difficulty in reaching target sites at active concentration, remain disadvantages that must be overcome. In this mini-review, by using Esc(1–21) as a reference, we have summarized how (i) substitution of natural amino acids by non-coded residues as well as (ii) peptide conjugation to AuNPs represent encouraging methodologies to optimize the biological properties of an AMP. Each synthetized analog/compound showed its own peculiarities according to its structural features (Table 1). Overall, the two different approaches should serve as an example to assist and to ameliorate the development of new peptide-based formulation for an efficient treatment of different types of infectious diseases. AuNPs@Esc(1–21) • Conjugation to AuNPs via PEG linker (∼16 peptide molecules per AuNP@PEG) • Higher activity against both planktonic and sessile forms of P. aeruginosa • Higher resistance to trypsin degradation • Invariant membrane- perturbing activity • Negligible cytotoxicity on human keratinocytes • Similar ≪wound≫healing effect *with respect to Esc(1–21). • Higher resistance to trypsin degradation • Invariant membrane- perturbing activity • Negligible cytotoxicity on human keratinocytes • Similar ≪wound≫healing effect *with respect to Esc(1–21). attached to the AuNPs via a gold-thiol bond (AuNPs@PEG), while the carboxylic group was used for further derivatization with the peptide via carbodiimide-mediated coupling (Casciaro et al., 2017). The Analog Esc(1–21)-1c Compound Structural Properties* Biological Features* [Aib1,10,18]- Esc(1–21) • Higher α-helical content in the secondary structure • Same activity against Gram- negative bacteria and yeasts • Higher activity against Gram- positive bacteria • Higher cytotoxicity against mammalian cells Esc(1–21)-1c • Lower α-helical content in the secondary structure • Higher resistance to proteolytic degradation • Slightly lower activity against the planktonic form of P. aeruginosa • Higher activity against the sessile form of P. aeruginosa • Lower cytotoxicity against mammalian cells • Greater efficacy in promoting migration of human lung epithelial cells AuNPs@Esc(1–21) • Conjugation to AuNPs via PEG linker (∼16 peptide molecules per AuNP@PEG) • Higher activity against both planktonic and sessile forms of P. aeruginosa • Higher resistance to trypsin degradation • Invariant membrane- perturbing activity • Negligible cytotoxicity on human keratinocytes • Similar ≪wound≫healing effect *with respect to Esc(1–21). TABLE 1 | Structural properties and biological features of the designed Esc(1–21)-derived compounds. disruption of the membrane and leakage of cytosolic material. Otherwise, our unconjugated bare-AuNPs did not show any anti- pseudomonal activity and were not detected around bacterial cells (Casciaro et al., 2017). This is in line with the findings that non-functionalized AuNPs are harmless also to other bacterial pathogens (Williams et al., 2006) and suggests that the cationic AMP represents the driving force allowing AuNPs@Esc(1–21) to reach the target site at high concentration. In addition, AuNPs@Esc(1–21) were resistant to proteolytic degradation preserving their antibacterial activity 2 h after treatment with trypsin (Casciaro et al., 2017). Finally, AuNPs@Esc(1–21) were harmless to keratinocytes and retained the peptide’s capability to stimulate migration of keratinocytes in a pseudo-“wound” healing assay. Altogether these findings make AuNPs@Esc(1– 21) an attractive nano-formulation for topical treatment of skin infections (Casciaro et al., 2017). • Slightly lower activity against the planktonic form of P. aeruginosa • Higher activity against the sessile form of P. aeruginosa • Lower cytotoxicity against mammalian cells The Analog Esc(1–21)-1c The Analog Esc(1 21) 1c With the aim to reduce the cytotoxicity and to protect Esc(1– 21) from proteolytic degradation, another analog carrying two D-amino acids was synthesized: Esc(1–21)-1c. It was obtained by replacing two L-amino acids i.e., Leu14 and Ser17 with the corresponding D-amino acid enantiomers (Figure 1). This diastereomer was rationally designed on the basis of the following considerations: (i) D-amino acids are known to be “α-helix breakers” (Grieco et al., 2013) and a reduction in the α-helix content of the peptide should reduce its propensity to perturb mammalian membranes leading to cell death (Strahilevitz et al., 1994); (ii) previous studies on the shorter analog Esc(1–18) pointed out that in electrically-neutral lipid vesicles the peptide adopted an α-helix conformation at its C-terminal half. With the purpose to disrupt at least the first turn of the α-helix expected to be present in the C-terminal half of Esc(1–21) in mammalian cell membranes, analogously to what found for Esc(1–18), Among the various NPs produced in recent years, AuNPs have attracted most attention due to their small size, high solubility, stability, biocompatibility, and chemical inertness (Connor et al., 2005). They can diffuse through all layers of human skin (Williams et al., 2006) and because of their large surface area, they can be functionalized with a high number of molecules (Yih and Al-Fandi, 2006; Pietro et al., 2016; Soica et al., 2016). Nevertheless, only a limited number of studies has been reported to date on the effects of conjugation of AMPs to AuNPs (Rai et al., 2016). By using Esc(1–21) as a model peptide, it was demonstrated for the first time how a chemical conjugation of an AMP via polyethylene glycol (PEG) linker to AuNPs increases its antimicrobial activity while retaining its mode of action without becoming toxic to human keratinocytes. AuNPs were synthetized by the citrate reduction of gold and stabilized with a bifunctional PEG bearing a thiol and a carboxylic group. The PEG was April 2017 | Volume 5 | Article 26 4 Amino Acids Substitution and Gold-Nanoparticles Casciaro et al. TABLE 1 | Structural properties and biological features of the designed Esc(1–21)-derived compounds. AUTHOR CONTRIBUTIONS Remarkably, the obtained AuNPs@Esc(1–21) resulted to be more active than the free peptide against both planktonic and sessile forms of P. aeruginosa. This was indicated by the corresponding minimal concentrations causing 50% killing of both bacterial phenotypes which were found to be ∼15-fold lower than those of the free Esc(1–21). This is presumably due to the higher concentration of peptide molecules at the site of bacterium-NP contact, as visualized by electron microscopy images which evidenced how these AuNPs@Esc(1– 21) form clusters at various points on the bacterial surface with BC wrote the review article; FC prepared and assembled the figure/table; MC and MM critically revised the manuscript. *with respect to Esc(1–21). REFERENCES Bechinger, B., and Gorr, S. U. (2017). Antimicrobial Peptides: mechanisms of action and resistance. J. Dent. Res. 96, 254–260. doi: 10.1177/0022034516679973 Ageitos, J. M., Sánchez-Pérez, A., Calo-Mata, P., and Villa, T. G. (2016). Antimicrobial peptides (AMPs): ancient compounds that represent novel weapons in the fight against bacteria. Biochem. Pharmacol. doi: 10.1016/j.bcp.2016.09.018. [Epub ahead of print]. Bellanda, M., Peggion, E., Bürgi, R., van Gunsteren, W., and Mammi, S. (2001). Conformational study of an Aib-rich peptide in DMSO by NMR. J. Pept. Res. 57, 97–106. doi: 10.1034/j.1399-3011.2001.00794.x Frontiers in Chemistry | www.frontiersin.org April 2017 | Volume 5 | Article 26 5 Amino Acids Substitution and Gold-Nanoparticles Casciaro et al. Biondi, B., Casciaro, B., Di Grazia, A., Cappiello, F., Luca, V., Crisma, M., et al. (2016). Effects of Aib residues insertion on the structural-functional properties of the frog skin-derived peptide esculentin-1a(1-21)NH2. Amino Acids 49, 139–150. doi: 10.1007/s00726-016-2341-x Grieco, P., Carotenuto, A., Auriemma, L., Saviello, M. R., Campiglia, P., Gomez- Monterrey, I. M., et al. (2013). The effect of D-amino acid substitution on the selectivity of temporin L towards target cells: identification of a potent anti-Candida peptide. Biochim. Biophys. Acta 1828, 652–660. doi: 10.1016/j.bbamem.2012.08.027 Boman, H. G. (1995). Peptide antibiotics and their role in innate immunity. Annu. Rev. Immunol. 13, 61–92. doi: 10.1146/annurev.iy.13.040195.000425 Hall, K., and Aguilar, M. I. (2010). Surface plasmon resonance spectroscopy for studying the membrane binding of antimicrobial peptides. Methods Mol. Biol. 627, 213–223. doi: 10.1007/978-1-60761-670-2_14 Cappiello, F., Di Grazia, A., Segev-Zarko, L. A., Scali, S., Ferrera, L., Galietta, L., et al. (2016). Esculentin-1a-derived peptides promote clearance of Pseudomonas aeruginosa internalized in bronchial cells of cystic fibrosis patients and lung cell migration: biochemical properties and a plausible mode of action. Antimicrob. Agents Chemother. 60, 7252–7262. doi: 10.1128/AAC.00904-16 Haslam, I. S., Roubos, E. W., Mangoni, M. L., Yoshizato, K., Vaudry, H., Kloepper, J. E., et al. (2014). From frog integument to human skin: dermatological perspectives from frog skin biology. Biol. Rev. Camb. Philos. Soc. 89, 618–655. doi: 10.1111/brv.12072 Casciaro, B., Moros, M., Rivera-Fernández, S., Bellelli, A., de la Fuente, J. M., and Mangoni, M. L. (2017). Gold-nanoparticles coated with the antimicrobial peptide esculentin-1a(1-21)NH2 as a reliable strategy for antipseudomonal drugs. Acta Biomater. 47, 170–181. doi: 10.1016/j.actbio.2016.09.041 Hemshekhar, M., Anaparti, V., and Mookherjee, N. (2016). Functions of cationic host defense peptides in immunity. Pharmaceuticals 9:40. doi: 10.3390/ph9030040 Islas-Rodrìguez, A. E., Marcellini, L., Orioni, B., Barra, D., Stella, L., and Mangoni, M. L. (2009). REFERENCES Peptides 71, 286–295. doi: 10.1016/j.peptides.2015.04.018 da Cunha, N. B., Cobacho, N. B., Viana, J. F., Lima, L. A., Sampaio, K. B., Dohms, S. S., et al. (2017). The next generation of antimicrobial peptides (AMPs) as molecular therapeutic tools for the treatment of diseases with social and economic impacts. Drug Discov. Today 22, 234–248. doi: 10.1016/j.drudis.2016.10.017 Mangoni, M. L., McDermott, A. M., and Zasloff, M. (2016). Antimicrobial peptides and wound healing: biological and therapeutic considerations. Exp. Dermatol. 25, 167–173. doi: 10.1111/exd.12929 De Zotti, M., Biondi, B., Park, Y., Hahm, K. S., Crisma, M., Toniolo, C., et al. (2012a). Antimicrobial lipopeptaibol trichogin GA IV: role of the three Aib residues on conformation and bioactivity. Amino Acids 43, 1761–1777. doi: 10.1007/s00726-012-1261-7 Mangoni, M. L., Miele, R., Renda, T. G., Barra, D., and Simmaco, M. (2001). The synthesis of antimicrobial peptides in the skin of Rana esculenta is stimulated by microorganisms. FASEB J. 15, 1431–1432. doi: 10.1096/fj.00-0695fje De Zotti, M., Biondi, B., Peggion, C., Formaggio, F., Park, Y., Hahm, K. S., et al. (2012b). Trichogin GA IV: a versatile template for the synthesis of novel peptaibiotics. Org. Biomol. Chem. 10, 1285–1299. doi: 10.1039/c1ob 06178j Marcellini, L., Borro, M., Gentile, G., Rinaldi, A. C., Stella, L., Aimola, P., et al. (2009). Esculentin-1b(1-18)–a membrane-active antimicrobial peptide that synergizes with antibiotics and modifies the expression level of a limited number of proteins in Escherichia coli. FEBS J. 276, 5647–5664. doi: 10.1111/j.1742-4658.2009.07257.x Di Grazia, A., Cappiello, F., Cohen, H., Casciaro, B., Luca, V., Pini, A., et al. (2015a). D-Amino acids incorporation in the frog skin-derived peptide esculentin-1a(1-21)NH2 is beneficial for its multiple functions. Amino Acids 47, 2505–2519. doi: 10.1007/s00726-015-2041-y Marín-Medina, N., Ramírez, D. A., Trier, S., and Leidy, C. (2016). Mechanical properties that influence antimicrobial peptide activity in lipid membranes. Appl. Microbiol. Biotechnol. 100, 10251–10263. doi: 10.1007/s00253-016-7975-9 Di Grazia, A., Cappiello, F., Imanishi, A., Mastrofrancesco, A., Picardo, M., Paus, R., et al. (2015b). The frog skin-derived antimicrobial peptide Esculentin-1a(1- 21)NH2 promotes the migration of human HaCaT keratinocytes in an EGF receptor-dependent manner: a novel promoter of human skin wound healing? PLoS ONE 10:e0128663. doi: 10.1371/journal.pone.0128663 Mazer-Amirshahi, M., Pourmand, A., and May, L. (2016). A review of newly approved antibiotics and antibiotics reserved for resistant infections: implications for emergency medicine. Am. J. Emerg. Med. 35, 154–158. doi: 10.1016/j.ajem.2016.10.034 Nicolas, P., and El Amri, C. (2009). The dermaseptin superfamily: a gene-based combinatorial library of antimicrobial peptides. Biochim. Biophys. REFERENCES Esculentin 1-21: a linear antimicrobial peptide from frog skin with inhibitory effect on bovine mastitis-causing bacteria. J. Pept. Sci. 15, 607–614. doi: 10.1002/psc.1148 Coccia, C., Rinaldi, A. C., Luca, V., Barra, D., Bozzi, A., Di Giulio, A., et al. (2011). Membrane interaction and antibacterial properties of two mildly cationic peptide diastereomers, bombinins H2 and H4, isolated from Bombina skin. Eur. Biophys. J. 40, 577–588. doi: 10.1007/s00249-011-0681-8 Kolar, S. S., Luca, V., Baidouri, H., Mannino, G., McDermott, A. M., and Mangoni, M. L. (2015). Esculentin-1a(1-21)NH2: a frog skin- derived peptide for microbial keratitis. Cell. Mol. Life Sci. 72, 617–627. doi: 10.1007/s00018-014-1694-0 Conlon, J. M. (2011a). The contribution of skin antimicrobial peptides to the system of innate immunity in anurans. Cell Tissue Res. 343, 201–212. doi: 10.1007/s00441-010-1014-4 König, E., Bininda-Emonds, O. R., and Shaw, C. (2015). The diversity and evolution of anuran skin peptides. Peptides 63, 96–117. doi: 10.1016/j.peptides.2014.11.003 Conlon, J. M. (2011b). Structural diversity and species distribution of host- defense peptides in frog skin secretions. Cell. Mol. Life Sci. 68, 2303–2315. doi: 10.1007/s00018-011-0720-8 Liu, S., Fan, L., Sun, J., Lao, X., and Zheng, H. (2016). Computational resources and tools for antimicrobial peptides. J. Pept. Sci. 23, 4–12. doi: 10.1002/psc.2947 Conlon, J. M., Kolodziejek, J., and Nowotny, N. (2004). Antimicrobial peptides from ranid frogs: taxonomic and phylogenetic markers and a potential source of new therapeutic agents. Biochim. Biophys. Acta 1696, 1–14. doi: 10.1016/j.bbapap.2003.09.004 Luca, V., Stringaro, A., Colone, M., Pini, A., and Mangoni, M. L. (2013). Esculentin(1-21), an amphibian skin membrane-active peptide with potent activity on both planktonic and biofilm cells of the bacterial pathogen Pseudomonas aeruginosa. Cell. Mol. Life Sci. 70, 2773–2786. doi: 10.1007/s00018-013-1291-7 Connor, E. E., Mwamuka, J., Gole, A., Murphy, C. J., and Wyatt, M. D. (2005). Gold nanoparticles are taken up by human cells but do not cause acute cytotoxicity. Small 1, 325–327. doi: 10.1002/smll.200400093 Mangoni, M. L., Fiocco, D., Mignogna, G., Barra, D., and Simmaco, M. (2003). Functional characterisation of the 1-18 fragment of esculentin- 1b, an antimicrobial peptide from Rana esculenta. Peptides 24, 1771–1777. doi: 10.1016/j.peptides.2003.07.029 d’Angelo, I., Casciaro, B., Miro, A., Quaglia, F., Mangoni, M. L., and Ungaro, F. (2015). Overcoming barriers in Pseudomonas aeruginosa lung infections: engineered nanoparticles for local delivery of a cationic antimicrobial peptide. Colloids Surf. B Biointerf. 135, 717–725. doi: 10.1016/j.colsurfb.2015.08.027 Mangoni, M. L., Luca, V., and McDermott, A. M. (2015). Fighting microbial infections: a lesson from amphibian skin-derived esculentin-1 peptides. REFERENCES Acta 1788, 1537–1550. doi: 10.1016/j.bbamem.2008.09.006 Fjell, C. D., Hiss, J. A., Hancock, R. E., and Schneider, G. (2012). Designing antimicrobial peptides: form follows function. Nat. Rev. Drug Discov. 11, 37–51. doi: 10.1038/nrd3591 Oren, Z., Lerman, J. C., Gudmundsson, G. H., Agerberth, B., and Shai, Y. (1999). Structure and organization of the human antimicrobial peptide LL-37 in phospholipid membranes: relevance to the molecular basis for its non-cell- selective activity. Biochem. J. 341(Pt 3), 501–513. Gellatly, S. L., and Hancock, R. E. (2013). Pseudomonas aeruginosa: new insights into pathogenesis and host defenses. Pathog. Dis. 67, 159–173. doi: 10.1111/2049-632X.12033 Giangaspero, A., Sandri, L., and Tossi, A. (2001). Amphipathic alpha helical antimicrobial peptides. Eur. J. Biochem. 268, 5589–5600. doi: 10.1002/1097- 0282(2000)55:1<4::AID-BIP30>3.0.CO;2-M Pietro, P. D., Strano, G., Zuccarello, L., and Satriano, C. (2016). Gold and silver nanoparticles for applications in theranostics. Curr. Top. Med. Chem. 16, 3069–3102. April 2017 | Volume 5 | Article 26 Frontiers in Chemistry | www.frontiersin.org 6 Amino Acids Substitution and Gold-Nanoparticles Casciaro et al. Powers, J. P., and Hancock, R. E. (2003). The relationship between peptide structure and antibacterial activity. Peptides 24, 1681–1691. doi: 10.1016/j.peptides.2003.08.023 Strahilevitz, J., Mor, A., Nicolas, P., and Shai, Y. (1994). Spectrum of antimicrobial activity and assembly of dermaseptin-b and its precursor form in phospholipid membranes. Biochemistry 33, 10951–10960. j Rai, A., Pinto, S., Velho, T. R., Ferreira, A. F., Moita, C., Trivedi, U., et al. (2016). One-step synthesis of high-density peptide-conjugated gold nanoparticles with antimicrobial efficacy in a systemic infection model. Biomaterials 85, 99–110. doi: 10.1016/j.biomaterials.2016. 01.051 Toniolo, C., Peggion, C., Crisma, M., Formaggio, F., Shui, X., and Eggleston, D. S. (1994). Structure determination of racemic trichogin A IV using centrosymmetric crystals. Nat. Struct. Biol. 1, 908–914. Wang, Y., Zhang, Y., Lee, W. H., and Yang, X. (2016). Novel peptides from skins of amphibians showed broad-spectrum antimicrobial activities. Chem. Biol. Drug Des. 87, 419–424. doi: 10.1111/cbdd.12672 Rink, R., Arkema-Meter, A., Baudoin, I., Post, E., Kuipers, A., Nelemans, S. A., et al. (2010). To protect peptide pharmaceuticals against peptidases. J. Pharmacol. Toxicol. Methods 61, 210–218. doi: 10.1016/j.vascn.2010. 02.010. Williams, D. N., Ehrman, S. H., and Pulliam Holoman, T. R. (2006). Evaluation of the microbial growth response to inorganic nanoparticles. J. Nanobiotechnology 4:3. doi: 10.1186/1477-3155-4-3 Shai, Y., and Oren, Z. (1996). Diastereoisomers of cytolysins, a novel class of potent antibacterial peptides. J. Biol. Chem. 271, 7305–7308. Yih, T. C., and Al-Fandi, M. (2006). Frontiers in Chemistry | www.frontiersin.org REFERENCES Engineered nanoparticles as precise drug delivery systems. J. Cell. Biochem. 97, 1184–1190. doi: 10.1002/jcb.20796. Zasloff, M. (1987). Magainins, a class of antimicrobial peptides from Xenopus skin: isolation, characterization of two active forms, and partial cDNA sequence of a precursor. Proc. Natl. Acad. Sci. U.S.A. 84, 5449–5453. Simmaco, M., Mangoni, M. L., Boman, A., Barra, D., and Boman, H. G. (1998). Experimental infections of Rana esculenta with Aeromonas hydrophila: a molecular mechanism for the control of the normal flora. Scand. J. Immunol. 48, 357–363. Simmaco, M., Mignogna, G., Barra, D., and Bossa, F. (1993). Novel antimicrobial peptides from skin secretion of the European frog Rana esculenta. FEBS Lett. 324, 159–161. Conflict of Interest Statement: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Simmaco, M., Mignogna, G., Barra, D., and Bossa, F. (1994). Antimicrobial peptides from skin secretions of Rana esculenta. Molecular cloning of cDNAs encoding esculentin and brevinins and isolation of new active peptides. J. Biol. Chem. 269, 11956–11961. Copyright © 2017 Casciaro, Cappiello, Cacciafesta and Mangoni. This is an open- access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Copyright © 2017 Casciaro, Cappiello, Cacciafesta and Mangoni. This is an open- access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Soica, C., Coricovac, D., Dehelean, C., Pinzaru, I., Mioc, M., Danciu, C., et al. (2016). Nanocarriers as tools in delivering active compounds for immune system related pathologies. Recent Pat. Nanotechnol. 10, 128–145. April 2017 | Volume 5 | Article 26 Frontiers in Chemistry | www.frontiersin.org 7
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Dynamics control in four-wave mixing processes in optical fiber
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Dynamics control in four-wave mixing processes in optical fiber Anastasiia Sheveleva1,*, Pierre Colman1, John M. Dudley2, Christophe Finot1 1Laboratoire Interdisciplinaire CARNOT de Bourgogne, UMR 6303 CNRS-Université de Bourgogne, Dijon, France 2Université de Franche-Comté, Institut FEMTO-ST, CNRS UMR 6174, Besançon, France Anastasiia Sheveleva1,*, Pierre Colman1, John M. Dudley2, Christophe Finot1 Abstract. A nonlinear interaction of waves in a dispersive medium manifests itself in a four-wave mixing process that can be described as an evolution of waves’ parameters on a phase plane in a form of closed orbits. Here we propose a method to control these trajectories and to switch from one state to another in an optimal manner by implementing an abrupt change of the average power. The method is confirmed experimentally by the reconstruction of a fundamental four-wave mixing dynamics in an idealized model using iterative propagation in a short segment of fiber. 1.2 Experimental setup In order to remain in the framework of the ideal FWM without any new cascaded spectral component, we developed a devoted experimental setup presented in Fig. 1 which relies on standard components of the telecommunication industry [3]. We generate a comb at 40 GHz from a continuous wave (CW) laser modulated by a phase modulator, which is then shaped in the frequency domain to reach the desired ,. The signal is amplified by an erbium-doped fiber amplifier (EDFA) to reach P0 and then propagates in a single-mode fiber (2 = -8 ps2 km-1 ;  = 1.7 W-1 km-1). By using a limited length of optical fiber (500 m), we avoid cascaded interactions as well as spurious additional nonlinear effects. The level of dissipation is negligeable. The output relative amplitude is measured with an optical spectrum analyser (OSA), and the phase is obtained from relative sinusoidal beating of two filtered signals measured on a high-speed sampling oscilloscope. After the output , are measured, the input is updated, and the process is repeated * Corresponding author: anastasiia.sheveleva@u-bourgogne.fr , 06020 (2023) EPJ Web of Conferences EOSAM 2023 287 , 06020 (2023) EPJ Web of Conferences EOSAM 2023 287 https://doi.org/10.1051/epjconf/202328706020 1 Introduction ( ) ( ) 2 2 3 2 1 cos 1 2 H      = − + + − , (1) and H H           = = −     . (2) The nonlinear Schrodinger equation is a basis of nonlinear fiber optics. In the focusing regime of propagation, the four-wave mixing (FWM) process can explain a broad range of observations such as modulation instability, generation of ultrashort high-repetition pulse trains, parametric amplification… In its simplest configuration, FWM involves the interaction of three waves (a strong continuous wave pump and two other components located symmetrically on both sides of this pump) with exchange of energy and phase variation. The dynamics of this system is of recurrent nature and can be depicted as closed orbits in reduced coordinates on a phase plane. The trajectories follow unique paths depending on the initial energy distribution and dephasing between the three waves as well as the average power [1]. Hence, it is impossible to link two states unless they belong to the same orbit. Here we seek to remove this fundamental limitation by introducing an approach based on an abrupt change of the average power. If it is done at a relevant point on the phase plane the switching allows an efficient transition between the two desired states. Here the 2 = sign(2)(2πfm )2/(|2|/P0) is a nonlinear mismatch parameter with P0 being the average power, 2 and  - the second-order dispersion and the nonlinear coefficient of a fiber, respectively.  = z/(P0) is the normalized distance. To characterize the dynamics, the evolution of  and  can be put on a phase plane: ( cos ,  sin). There exist two families of solutions following the recurrent orbits, that are divided by a separatrix [1, 2]. © The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http ://creativecommons.org/licenses/by/4.0/). s DP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 nses/by/4.0/). References 1. S. Trillo and S. Wabnitz, Opt. Lett. 16, 986-988 (1991). 2. C. Naveau et al., Front. Phys. 9 :637812 (2021) 3. Sheveleva, U. Andral, B. Kibler, P. Colman, J.M. Dudley, C. Finot, Optica 9, 656-662 (2022) 4. A. Sheveleva, P. Colman, J. M. Dudley, and C. Finot, Opt. Lett. 47, 6317-6320 (2022). 5. A. Bendahmane et al, Opt. Lett. 39, 4490-4493 (2014). 6. A. Gomel et al, Phys. Rev. Lett. 126, 174501 (2021). 7. Z. Deng, J. Zhang, D. Fan, and L. Zhang, New J. Phys. 24, 063018 (2022). 8. A. Sheveleva, P. Colman, J.M. Dudley, C. Finot, Opt. Comm. 129472 (2023). arXiv:2303.08469 1. S. Trillo and S. Wabnitz, Opt. Lett. 16, 986-988 (1991). 1. S. Trillo and S. Wabnitz, Opt. Lett. 16, 986-988 (1991). 3. Sheveleva, U. Andral, B. Kibler, P. Colman, J.M. Dudley, C. Finot, Optica 9, 656-662 (2022) 4. A. Sheveleva, P. Colman, J. M. Dudley, and C. Finot, Opt. Lett. 47, 6317-6320 (2022). 5. A. Bendahmane et al, Opt. Lett. 39, 4490-4493 (2014). 6. A. Gomel et al, Phys. Rev. Lett. 126, 174501 (2021). 3.1 Principle Early experiments in fiber optics or hydrodynamics have already explored the idea of an abrupt change of the medium properties to freeze the longitudinal evolution of a breathing wave [5,6]. Indeed, depending on the fiber characteristics the orbits would have different shapes and the normalized mismatch parameter  in Eq. (1) will change. Therefore,  represents a key control parameter [7] which change will enable a control of dynamics and states transitions. In our approach, instead of varying the fiber properties, we choose the average power as a the degree of freedom and we do not restrict ourself to targeting a stationary state. Fig. 2 Experimental trajectories that connect (a) IN = 0.90, IN =  and OUT = 0.90, OUT = 0, (b) IN = 0.90, IN = 0 and OUT = 0.80, OUT = 0, by an abrupt power change. The colour depicts value of input average power that is used for each part of the trajectory. Conclusion We have conceptually and experimentally demonstrated that an abrupt change of the average power allows tailored manipulation of the ideal FWM dynamics and can help to connect two states that are not part of the same orbit [8]. We have conceptually and experimentally demonstrated that an abrupt change of the average power allows tailored manipulation of the ideal FWM dynamics and can help to connect two states that are not part of the same orbit [8]. This switching technique is robust to small deviations from the ideal simulations. The results follow well the numerical predictions, and the theoretical estimation of the switching point is accurate. If there are no limitations in reachable values of , any two points on the phase plane can be connected by a single abrupt change of this parameter. In practice, however, experimental conditions limit the control: we consider fixed fiber characteristics, and the input power is restricted in order not to damage the equipment. In our case, only values 2  [-2.51 : -0.95] can be reached. This switching technique is robust to small deviations from the ideal simulations. The results follow well the numerical predictions, and the theoretical estimation of the switching point is accurate. To make a state transition, first, we select the input IN, IN and the output OUT, OUT points we want to connect. Then, using a Hamiltonian conservation, we find all reachable states for both points within the given limits of . Out of this range of reachable states we find an optimum, i.e. an intersection point that allows to connect input and output on the shortest propagation length. To change the  we adjust the input power accordingly in the intersection point. 1.1 Theoretical background An ideal FWM assumes that nonlinear interaction occurs solely between the pump 0 and the two spectral lines ±1 at ±m (with m = 2πfm being the modulation frequency). To describe the dynamics, one may use reduced parameters: the relative spectral amplitude  = |0|2/ |i|2 and the relative phase  = -1 + 1 - 20 with i being the phase of each spectral line. In this case the evolution of spectral lines with propagation distance can be described by the one-dimensional conservative Hamiltonian [1]: , 06020 (2023) EPJ Web of Conferences EOSAM 2023 287 https://doi.org/10.1051/epjconf/202328706020 continuously, so that a complete trajectory can be reconstructed. Note that an alternative design of this setup has been developed to benefit to machine-learning approaches [4]. the trajectory can cross the separatrix and switch to another type of dynamics (panel (a)). The transition takes 11 km with a switching taking place after 6.5 km. It is also possible to control the orbits within the same family of solutions (panel (b)). Here a trajectory starting on the right side makes a transition to the inner orbit after power increase by 1 dB. Fig. 1 Experimental setup. PC – polarization controller, Att. – attenuator, OBPF – optical band pass filter, PD – photodiode, RF amp. – radiofrequency amplifier. Fig. 2 Experimental trajectories that connect (a) IN = 0.90, IN =  and OUT = 0.90, OUT = 0, (b) IN = 0.90, IN = 0 and OUT = 0.80, OUT = 0, by an abrupt power change. The colour depicts value of input average power that is used for each part of the trajectory. Fig. 1 Experimental setup. PC – polarization controller, Att. – attenuator, OBPF – optical band pass filter, PD – photodiode, RF amp. – radiofrequency amplifier. 8. A. Sheveleva, P. Colman, J.M. Dudley, C. Finot, Opt. Comm. 129472 (2023). arXiv:2303.08469 3.1 Experimental demonstration 7. Z. Deng, J. Zhang, D. Fan, and L. Zhang, New J. Phys. 24, 063018 (2022). Two examples of experimental demonstrations are presented in Fig. 2 (solid lines ; dashed lines represent ideal close orbits for the input and output powers). We confirm that with a single change in the average power, 8. A. Sheveleva, P. Colman, J.M. Dudley, C. Finot, Opt. Comm. 129472 (2023). arXiv:2303.08469 2
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Novel Deep Learning Approaches for Mapping Variation of Ground Level from Spirit Level Measurements Abstract: This study investigates the use of new machine learning techniques in mapping variation in 15 ground levels based on ordinary spirit levelling (SL) measurements. Convolution Neural Network (CNN), 16 Recurrent Neural Networks (RNN), Long Short-Term Memory (LSTM), and bi-directional LSTM (BI- 17 LSTM) were developed and compared in the current study to estimate the leveling through SL 18 measurements. SL measurements of the Manzalla region, Egypt, were used in the current study. 3253 19 datasets of SL observation points, including 229 benchmarks of precise levelling (PL), were used to design 20 and verify the proposed model’s results. The results show the developed LSTM model outperforms CNN, 21 RNN, and BI-LSTM in modeling ground leveling in the training and testing stages. The root mean square 22 error and correlation determination of the LSTM model are 7.4 cm and 0.99, respectively, in the testing 23 stage. The accuracy of mapping ground levelling through the developed LSTM model is close to 99% in 24 terms of model error. 25 https://doi.org/10.5194/gmd-2023-62 Preprint. Discussion started: 12 April 2023 c⃝Author(s) 2023. CC BY 4.0 License. Novel Deep Learning Approaches for Mapping Variation of Ground Level from Spirit Level 1 Measurements 2 Fawzi Zarzoura 1, Mosbeh R. Kaloop1,2,3,4, Pijush Samui5, Jong Wan Hu2,3*, Md Shayan Sabri5, Tamer 3 ElGharbawi6 4 1Public Works Engineering Department, Mansoura University, Mansoura, Egypt 5 2Department of Civil and Environmental Engineering, Incheon National University, Incheon, Korea 6 3Incheon Disaster Prevention Research Center, Incheon National University, Incheon, Korea 7 4 DigInnoCent s.r.o., Liberec, Czech Republic 8 5Department of Civil Engineering, National Institute of Technology Patna, Patna, India 9 6Civil Engineering Department, Suez Canal University, Ismailia, Egypt 10 *Correspondence to: Jong Wan Hu (jongp24@inu.ac.kr) 11 (F.Zarzoura: fawzihamed@mans.edu.eg ; M.Kaloop:mosbeh@mans.edu.eg, P.Samui: pijush@nitp.ac.in ; 12 M.Sabri: mds.pg21.ce@nitp.ac.in; T.ElGharabawi: tgh@eng.suez.edu.eg) 13 14 Abstract: This study investigates the use of new machine learning techniques in mapping variation in 15 ground levels based on ordinary spirit levelling (SL) measurements. Convolution Neural Network (CNN), 16 Recurrent Neural Networks (RNN), Long Short-Term Memory (LSTM), and bi-directional LSTM (BI- 17 LSTM) were developed and compared in the current study to estimate the leveling through SL 18 measurements. SL measurements of the Manzalla region, Egypt, were used in the current study. 3253 19 datasets of SL observation points, including 229 benchmarks of precise levelling (PL), were used to design 20 and verify the proposed model’s results. The results show the developed LSTM model outperforms CNN, 21 RNN, and BI-LSTM in modeling ground leveling in the training and testing stages. The root mean square 22 error and correlation determination of the LSTM model are 7.4 cm and 0.99, respectively, in the testing 23 stage. The accuracy of mapping ground levelling through the developed LSTM model is close to 99% in 24 terms of model error. 25 Novel Deep Learning Approaches for Mapping Variation of Ground Level from Spirit Level 1 Measurements 2 Fawzi Zarzoura 1, Mosbeh R. Kaloop1,2,3,4, Pijush Samui5, Jong Wan Hu2,3*, Md Shayan Sabri5, Tamer 3 ElGharbawi6 4 1Public Works Engineering Department, Mansoura University, Mansoura, Egypt 5 2Department of Civil and Environmental Engineering, Incheon National University, Incheon, Korea 6 3Incheon Disaster Prevention Research Center, Incheon National University, Incheon, Korea 7 4 DigInnoCent s.r.o., Liberec, Czech Republic 8 5Department of Civil Engineering, National Institute of Technology Patna, Patna, India 9 6Civil Engineering Department, Suez Canal University, Ismailia, Egypt 10 *Correspondence to: Jong Wan Hu (jongp24@inu.ac.kr) 11 (F.Zarzoura: fawzihamed@mans.edu.eg ; M.Kaloop:mosbeh@mans.edu.eg, P.Samui: pijush@nitp.ac.in ; 12 M.Sabri: mds.pg21.ce@nitp.ac.in; T.ElGharabawi: tgh@eng.suez.edu.eg) 13 14 Abstract: This study investigates the use of new machine learning techniques in mapping variation in 15 ground levels based on ordinary spirit levelling (SL) measurements. Convolution Neural Network (CNN), 16 Recurrent Neural Networks (RNN), Long Short-Term Memory (LSTM), and bi-directional LSTM (BI- 17 LSTM) were developed and compared in the current study to estimate the leveling through SL 18 measurements. SL measurements of the Manzalla region, Egypt, were used in the current study. 3253 19 datasets of SL observation points, including 229 benchmarks of precise levelling (PL), were used to design 20 and verify the proposed model’s results. The results show the developed LSTM model outperforms CNN, 21 RNN, and BI-LSTM in modeling ground leveling in the training and testing stages. The root mean square 22 error and correlation determination of the LSTM model are 7.4 cm and 0.99, respectively, in the testing 23 stage. The accuracy of mapping ground levelling through the developed LSTM model is close to 99% in 24 terms of model error. 25 1. Introduction 27 54 However, due to the limitations of the data used in modeling the geoid, the use of deep learning in geoid 55 modeling is still limited. 56 Nowadays, Deep learning techniques, such as convolutional neural networks (CNN), recurrent neural 57 networks (RNN), long short-term memory (LSTM), have been used in modeling and classifying land 58 use/land cover (LULC) based on satellite images. Rußwurm and Korner (Rußwurm and Körner 2017) found 59 LSTM to be more efficient in LULC classification. Sun et al. (Sun et al. 2019) evaluated LSTM-RNN, 60 RCNN, and CNN in mapping and classification LULC; their results found the LSTM-RNN model can be 61 precisely used in LULC. Modeling of Land-use and land-cover change (LULCC) through machine learning 62 techniques was collected and discussed in Wang et al. (Wang et al. 2022); the review summarized that 63 machine and deep learning may be limited in “(i) describing occurrence, transition, and spatial patterns of 64 changes ; (ii) unavailability of training data for all the change drivers, particularly sequence data, and (iii) 65 lack of inclusion of local ecological, hydrological, and social-economic drivers when addressing the 66 spectral feature change”. Bi-directional long short-term memory (Bi-LSTM) was integrated with the 67 optimal guidance-whale optimization algorithm (OG-WOA) technique to classify and map the LULC 68 (Vinaykumar et al. 2023). The accuracy of Bi-LSTM was found to be better than that of CNN and RNN in 69 LULC classification. Furthermore, CNN, Deep Boltzmann Machines (DBM), Deep Belief Net (DBN), and 70 RNN are used to estimate and evaluate the geodetic velocity, and the results showed that the CNN was 71 better than other deep learning models (Sorkhabi et al. 2022). Other applications of soft computing 72 techniques in water leveling and wave height modeling can be found in (Kaloop et al. 2016, 2020a; Miky et 73 al. 2021; Sinha and Abernathey 2021; Minuzzi and Farina 2023). 74 Therefore, this study aims to use deep learning techniques, such as CNN, RNN, LSTM, and BI-LSTM, in 75 the elevation interpolation of grid points. With modeling the ground leveling, even in the relative 76 measurements, the time and cost of traditional leveling fieldworks should be decreased. To train the 77 proposed models, 3253 datasets leveling points of SL, including 229 benchmarks of precise levelling (PL), 78 were used. These measurements were collected from a project in the Manzalla region, Egypt. 1. Introduction 27 2021; Sinha and Abernathey 2021; Minuzzi and Farina 2023). 74 Therefore, this study aims to use deep learning techniques, such as CNN, RNN, LSTM, and BI-LSTM, in 75 the elevation interpolation of grid points. With modeling the ground leveling, even in the relative 76 measurements, the time and cost of traditional leveling fieldworks should be decreased. To train the 77 proposed models, 3253 datasets leveling points of SL, including 229 benchmarks of precise levelling (PL), 78 were used. These measurements were collected from a project in the Manzalla region, Egypt. The accuracy 79 of the proposed models was evaluated based on the collected datasets; this means the accuracy should be 80 changed based on the volume of data used and the topography of the study regions. However, the concept 81 of the proposed models can be used in a similar area. 82 found in (Kemboi 2016; LSC 2018). Machine learning was applied for modeling the geoid undulation 41 (Yιlmaz et al. 2006; Kaloop et al. 2020b; Tütüncü et al. 2021; Asenso-Gyambibi et al. 2022). However, 42 mapping variation in earth surface or surface elevation through SP is still limited based on our literature. 43 Latitude and longitude are commonly used in leveling modeling (Veronez et al. 2011; Erol and Erol 2013). 44 Erol and Erol (Erol and Erol 2013) applied multivariable polynomial regression equations (MPRE), artificial 45 neural networks (ANNs), adaptive network-based fuzzy inference system (ANFIS) and especially wavelet 46 neural networks (WNNs) to interpolate the geoid surface; ANFIS and WNN outperformed other models. 47 In addition, the ANN model was tested to estimate the geoid height in Brazil, and the results found it was 48 efficient compared to the Brazilian geoid model (MAPGEO2004) (Veronez et al. 2011). Kernel Ridge 49 Regression (KRR) was applied to estimate the Kuwait geoid model based on GPS/Levelling measurements, 50 with the results that its performance is better than that of least squares support vector regression (LSSVR), 51 gaussian process regression (GPR), and multivariate adaptive regression splines (MARS) in modeling the 52 geoid (Kaloop et al. 2019). More studies can be found in (Zhong 1997; Veronez et al. 2011; Rabah and 53 Kaloop 2013; Sorkhabi et al. 2015; Kaloop et al. 2018; Tütüncü et al. 2021) for modeling the geoid. 1. Introduction 27 Modeling the variation of the earth's surface is one of the essential requirements in engineering applications. 28 Traditional leveling methods are commonly used in small scale engineering projects; however, satellite 29 systems, e.g., satellite images and coordinate systems such as global positioning systems (GPS), are 30 commonly used in large-scale projects (Ahmed EL-Mowafy 2004; IHO 2011; CDT 2012; Shanker and 31 Acharya 2022). Ordinary spirit levelling (SP) is a lower-cost method compared to other surveying methods, 32 and it is almost always used to cover a wide area of construction projects. However, satellite systems and 33 precise leveling (PL) are almost as costly and used in special survey engineering networks (Karila et al. 34 2013; Kemboi 2016; Janos et al. 2022). In order to decrease the cost and time of survey engineering works, 35 this study aims to develop a soft computing technique that can be used to map variations of the earth's 36 surface through SP measurements in construction and infrastructure projects. 37 SP, or levelling, is a process to estimate the land elevation of a measured point based on the known elevation 38 of another point with a level instrument and an ordinary vertical staff. It is known as a relative measurement 39 of leveling with low accuracy. However, it is widely used in construction projects. The details of SP can be 40 1 https://doi.org/10.5194/gmd-2023-62 Preprint. Discussion started: 12 April 2023 c⃝Author(s) 2023. CC BY 4.0 License. https://doi.org/10.5194/gmd-2023-62 Preprint. Discussion started: 12 April 2023 c⃝Author(s) 2023. CC BY 4.0 License. found in (Kemboi 2016; LSC 2018). Machine learning was applied for modeling the geoid undulation 41 (Yιlmaz et al. 2006; Kaloop et al. 2020b; Tütüncü et al. 2021; Asenso-Gyambibi et al. 2022). However, 42 mapping variation in earth surface or surface elevation through SP is still limited based on our literature. 43 Latitude and longitude are commonly used in leveling modeling (Veronez et al. 2011; Erol and Erol 2013). 44 Erol and Erol (Erol and Erol 2013) applied multivariable polynomial regression equations (MPRE), artificial 45 neural networks (ANNs), adaptive network-based fuzzy inference system (ANFIS) and especially wavelet 46 neural networks (WNNs) to interpolate the geoid surface; ANFIS and WNN outperformed other models. 47 In addition, the ANN model was tested to estimate the geoid height in Brazil, and the results found it was 48 efficient compared to the Brazilian geoid model (MAPGEO2004) (Veronez et al. 2011). 1. Introduction 27 Kernel Ridge 49 Regression (KRR) was applied to estimate the Kuwait geoid model based on GPS/Levelling measurements, 50 with the results that its performance is better than that of least squares support vector regression (LSSVR), 51 gaussian process regression (GPR), and multivariate adaptive regression splines (MARS) in modeling the 52 geoid (Kaloop et al. 2019). More studies can be found in (Zhong 1997; Veronez et al. 2011; Rabah and 53 Kaloop 2013; Sorkhabi et al. 2015; Kaloop et al. 2018; Tütüncü et al. 2021) for modeling the geoid. 54 However, due to the limitations of the data used in modeling the geoid, the use of deep learning in geoid 55 modeling is still limited. 56 Nowadays, Deep learning techniques, such as convolutional neural networks (CNN), recurrent neural 57 networks (RNN), long short-term memory (LSTM), have been used in modeling and classifying land 58 use/land cover (LULC) based on satellite images. Rußwurm and Korner (Rußwurm and Körner 2017) found 59 LSTM to be more efficient in LULC classification. Sun et al. (Sun et al. 2019) evaluated LSTM-RNN, 60 RCNN, and CNN in mapping and classification LULC; their results found the LSTM-RNN model can be 61 precisely used in LULC. Modeling of Land-use and land-cover change (LULCC) through machine learning 62 techniques was collected and discussed in Wang et al. (Wang et al. 2022); the review summarized that 63 machine and deep learning may be limited in “(i) describing occurrence, transition, and spatial patterns of 64 changes ; (ii) unavailability of training data for all the change drivers, particularly sequence data, and (iii) 65 lack of inclusion of local ecological, hydrological, and social-economic drivers when addressing the 66 spectral feature change”. Bi-directional long short-term memory (Bi-LSTM) was integrated with the 67 optimal guidance-whale optimization algorithm (OG-WOA) technique to classify and map the LULC 68 (Vinaykumar et al. 2023). The accuracy of Bi-LSTM was found to be better than that of CNN and RNN in 69 LULC classification. Furthermore, CNN, Deep Boltzmann Machines (DBM), Deep Belief Net (DBN), and 70 RNN are used to estimate and evaluate the geodetic velocity, and the results showed that the CNN was 71 better than other deep learning models (Sorkhabi et al. 2022). Other applications of soft computing 72 techniques in water leveling and wave height modeling can be found in (Kaloop et al. 2016, 2020a; Miky et 73 al. 1. Introduction 27 The accuracy 79 of the proposed models was evaluated based on the collected datasets; this means the accuracy should be 80 changed based on the volume of data used and the topography of the study regions. However, the concept 81 of the proposed models can be used in a similar area. 82 83 2 https://doi.org/10.5194/gmd-2023-62 Preprint. Discussion started: 12 April 2023 c⃝Author(s) 2023. CC BY 4.0 License. 2. Methods 84 In this study, four input-output deep learning techniques, CNN, RNN, LSTM, and BI-LSTM, are applied 85 and compared to map the leveling based on Latitude and longitude measurements. The following is a theory 86 summary of the proposed models. 87 2.1. Convolution neural network (CNN) 88 CNN is one of the most essential deep learning methods, in which multiple layers are powerfully trained. 89 The convolutional layer is the center of the CNN and is the cause of its name. This layer receives and 90 processes data by performing a convolution function. The CNN is made up of multiple convolutional layers 91 that can be integrated or completely connected, as well as multilayer perceptron’s (Oh et al. 2019; Wang et 92 al. 2020; Zhang et al. 2022; Sorkhabi et al. 2022). This approach is very effective and one of the most 93 popular approaches in a variety of computer vision applications. The convolution layer, the pooling layer, 94 and the fully connected layer are the three major layers that make up a CNN network. 95 Different layers carry out different tasks (Jang et al. 2019). The architecture of 1D conventional Neural 96 Network (1D-CNN) for layer-by-layer leveling is shown in Figure 1.a. In general, there are two training 97 phases in each CNN: the feedforward phase and the backpropagation phase. The input signal is fed into the 98 network in the first stage, which consists of multiplying the input by the parameters of each neuron and 99 then performing convolution in each layer to produce the network output (Sorkhabi et al. 2022). In this 100 case, the network parameters are modified, or to put it another way, the network is trained, and the output 101 product is used to figure out how much network error there is. To do this, compute the error rate by 102 comparing the network output with an accurate response using an error function (loss function). 1. Introduction 27 Based on 103 the calculated error rate, the backpropagation process starts in the following step. The gradient of each 104 parameter is determined in this phase using the chain rule, and all parameters are changed based on their 105 impact on the error introduced into the network (Sorkhabi et al. 2022). Following the updating of the 106 parameters, the following feed-forward process starts. The network training comes to a conclusion after 107 repeating a significant number of these steps (Sorkhabi et al. 2022). In general, a convolutional neural 108 network is a hierarchical neural network that has a number of completely connected layers after the pooling 109 and convolutional layers. 110 Different layers carry out different tasks (Jang et al. 2019). The architecture of 1D conventional Neural 96 Network (1D-CNN) for layer-by-layer leveling is shown in Figure 1.a. In general, there are two training 97 phases in each CNN: the feedforward phase and the backpropagation phase. The input signal is fed into the 98 network in the first stage, which consists of multiplying the input by the parameters of each neuron and 99 then performing convolution in each layer to produce the network output (Sorkhabi et al. 2022). In this 100 case, the network parameters are modified, or to put it another way, the network is trained, and the output 101 product is used to figure out how much network error there is. To do this, compute the error rate by 102 comparing the network output with an accurate response using an error function (loss function). Based on 103 the calculated error rate, the backpropagation process starts in the following step. The gradient of each 104 parameter is determined in this phase using the chain rule, and all parameters are changed based on their 105 impact on the error introduced into the network (Sorkhabi et al. 2022). Following the updating of the 106 parameters, the following feed-forward process starts. The network training comes to a conclusion after 107 repeating a significant number of these steps (Sorkhabi et al. 2022). In general, a convolutional neural 108 network is a hierarchical neural network that has a number of completely connected layers after the pooling 109 and convolutional layers. 110 2.2. Recurrent neural networks (RNN) The convolutional model works with a fixed number of inputs and produces a fixed vector as an output 113 with a predefined number of steps. We can manipulate vector sequences at both the input and the output 114 thanks to return grids (Hang et al. 2019; Sorkhabi et al. 2022; Amalou et al. 2022). In the case of the RNN, 115 the link between the units forms a direct cycle. The inputs and outputs of a recursive neural network are 116 connected rather than independent, in contrast to conventional neural networks. Additionally, each layer of 117 the RNN uses the same standard settings. RNN design is shown in Figure 1.b. The backpropagation method 118 can be used to train the return network to mimic a conventional neural network (Hang et al. 2019). Here, 119 the flow step is only one factor that is considered in the computation of the gradient. The two-way neural 120 network takes into account both the expected future output and the prior output. Deep learning can be 121 achieved in two-way and direct RNN by adding numerous hidden levels. With a lot of learning data, these 122 deep networks have a greater learning capacity (Sorkhabi et al. 2022). 123 3 https://doi.org/10.5194/gmd-2023-62 Preprint. Discussion started: 12 April 2023 c⃝Author(s) 2023. CC BY 4.0 License. (a) (b) Figure 1. Diagram of Leveling estimation using (a) 1D convolution CNN and (b) Simple RNN (b) D l i CNN d (b) Si l RNN Figure 1. Diagram of Leveling estimation using (a) 1D convolution CNN and (b) Simple RNN 2.3. Long short-term memory (LSTM) LSTM is a model or structure for sequential data created by (Hochreiter and Schmidhuber 1997) for the 126 advancement of RNN. It employs a unique combination of hidden units, elementwise products, and sums 127 between units to create gates that control "memory cells." These cells are intended to store information 128 without modification for extended periods of time (Apaydin et al. 2020). The most important feature of 129 LSTM is its capacity to learn long-term dependency, which RNNs cannot do. To anticipate the next step, 130 the weight values on the network must be updated, which necessitates the preservation of information from 131 the previous steps. RNN can only learn a finite number of short-term relationships and cannot learn long- 132 term series. 2.2. Recurrent neural networks (RNN) However, because LSTM has three gates—input, forget, and output—it can effectively learn 133 these long-term relationships. (Figure 2a). To show how much of the prior memory is remembered and how 134 much of it has been lost, the forget gate is embedded. The concealed state ℎ𝑡 for LSTM is calculated as 135 follows: 136 𝑖𝑡= 𝜎(𝑤𝑖𝑋𝑡+ 𝑢𝑖ℎ𝑡−1 + 𝑏𝑖) (1) 137 𝑓𝑡= 𝜎(𝑤𝑓𝑋𝑡+ 𝑢𝑓ℎ𝑡−1 + 𝑏𝑓) (2) 138 𝑂𝑡= 𝜎(𝑤𝑂𝑋𝑡+ 𝑢𝑂ℎ𝑡−1 + 𝑏𝑂) (3) 139 𝐶̃𝑡= 𝑡𝑎𝑛ℎ(𝑤𝐶𝑋𝑡+ 𝑢𝐶ℎ𝑡−1 + 𝑏𝐶) (4) 140 𝐶𝑡= 𝑓𝑡× 𝐶𝑡−1 + 𝑖𝑡× 𝐶̃𝑡 (5) 141 ℎ𝑡= tanh⁡(𝐶𝑡) × 𝑂𝑡 (6) 142 Where, 𝑖𝑡, 𝑓𝑡, 𝑎𝑛𝑑⁡𝑂𝑡 are the input, forget, and output gates at time t, respectively; 𝑤𝑖, 𝑤𝑓, 𝑤𝑂, 𝑎𝑛𝑑⁡𝑤𝐶 are 143 weights that map the hidden layer input to the three gates of input, forget, and output while 144 𝑢𝑖, 𝑢𝑓, 𝑢𝑂, 𝑎𝑛𝑑⁡𝑢𝐶 weights matrices map the hidden layer output to gates; 𝑏𝑖, 𝑏𝑓, 𝑏𝑂, 𝑎𝑛𝑑⁡𝑏𝐶⁡are vectors. 145 Additionally, 𝐶𝑡⁡𝑎𝑛𝑑⁡ℎ𝑡 represent the results of the cell and stratum, respectively (Apaydin et al. 2020). 146 147 2.4. Bi-directional long short-term memory (Bi-LSTM) 148 Similarly, the optimal BI-LSTM network 172 consist of a two-input layer, one hidden BI-LSTM layer with 64 neurons, and one output layer. Notably, 173 the 'sigmoid' function was utilized in each hidden layer, while the Adam and mean squared errors were used 174 for model fitness and optimization, respectively, in both of the models. It is also noted that, different epoch 175 numbers of 100, 300, and 500 were tested in each run of the LSTM and BI-LSTM models, with the optimum 176 epoch found to be 500. 177 Table 1. Parametric configuration of the developed models 178 Model Optimum model configuration CNN 1D convolutional layer, flatten layer, dense layer, learning rate = 0.0001 batch size = 10, epoch = 500 RNN 20 hidden neurons in simple RNN layer, 8 hidden neurons in dense layer, input shape = (2,1), learning rate = 0.0001, batch size = 16, epoch = 500 LSTM 100 hidden neurons, input shape = (2,1), learning rate = 0.01, batch size = 15, epoch = 500 BI-LSTM 64 hidden neurons, input shape = (2,1), learning rate = 0.01, batch size = 15, epoch = 500 repeatedly using inverted inputs [36]. Both the forward and backward layers outputs are calculated similarly 155 to the unidirectional LSTM. In the Bi-LSTM layer, Yt is computed from Equation (7): 156 𝑌= 𝜎(ℎ⃗ ℎ⃖⃗) (7) 157 repeatedly using inverted inputs [36]. Both the forward and backward layers outputs are calculated similarly 155 to the unidirectional LSTM. In the Bi-LSTM layer, Yt is computed from Equation (7): 156 ⃗ ⃖⃗ repeatedly using inverted inputs [36]. Both the forward and backward layers outputs are calculated similarly 155 to the unidirectional LSTM. In the Bi-LSTM layer, Yt is computed from Equation (7): 156 𝑌𝑡= 𝜎(ℎ⃗ 𝑡, ℎ⃖⃗𝑡) (7) 157 where 𝜎 function is used to combine the two output sequences. 158 Figure 2. LSTM (a) and BI-LSTM (b) diagrams for levelling prediction (Apaydin et al. 2020) 159 (7) ( ) sequences. where 𝜎 function is used to combine the two output sequences. where 𝜎 function is used to combine the two output sequences. Figure 2. LSTM (a) and BI-LSTM (b) diagrams for levelling prediction (Apaydin et al. 2020) 2.5. Design models and evaluation 160 g To design the proposed models, CNN, RNN, LSTM, and BI-LSTM, trial-and-error runs were performed. 161 Table 1 proposes the details of the model`s configuration. 2.4. Bi-directional long short-term memory (Bi-LSTM) 148 In fact, the network is processed in two directions rather than just one: backward and forward, with two 149 distinct hidden levels. Bidirectional networks performed better than unidirectional networks in situations 150 like phonemic grouping, as shown by Graves and Schmidhuber (Graves and Schmidhuber 2005). Figure 151 2b shows the bidirectional network's layout. These networks have a structure with a forward and backward 152 LSTM layer based on this image. The forward layer output order, ℎ⃗ 𝑡, is computed repeatedly from time⁡𝑡− 153 𝑛 to time⁡𝑡−1 using positive order inputs, whereas the backward layer outcome order, ℎ⃖⃗𝑡, is computed 154 4 https://doi.org/10.5194/gmd-2023-62 Preprint. Discussion started: 12 April 2023 c⃝Author(s) 2023. CC BY 4.0 License. repeatedly using inverted inputs [36]. Both the forward and backward layers outputs are calculated similarly 155 to the unidirectional LSTM. In the Bi-LSTM layer, Yt is computed from Equation (7): 156 𝑌𝑡= 𝜎(ℎ⃗ 𝑡, ℎ⃖⃗𝑡) (7) 157 where 𝜎 function is used to combine the two output sequences. 158 Figure 2. LSTM (a) and BI-LSTM (b) diagrams for levelling prediction (Apaydin et al. 2020) 159 2.5. Design models and evaluation 160 To design the proposed models, CNN, RNN, LSTM, and BI-LSTM, trial-and-error runs were performed. 161 Table 1 proposes the details of the model`s configuration. The optimum CNN consists of two input layers, 162 one convolutional layer with 32 neurons followed by a flat layer, a dense layer with 64 neurons, and an 163 output layer. For the best model fit and optimization, mean square error and Adam were used. For a simple 164 RNN, the number of hidden neurons in the hidden layers was investigated in the range of 2 to 40 using trial 165 and error approach, the appropriate value of hidden neuron was determined to be 20 and 8 for the two 166 hidden layers, respectively. The optimum RNN model consists of two input layers, a simple RNN hidden 167 layer with 20 neurons followed by a dense layer with 8 neurons, and an output layer. In each hidden layer, 168 ReLU (rectified linear unit) was used as the activation function. In particular, "mean square error" and 169 "rmsprop" were utilized in the processes of model fitness and optimization, respectively. To achieve optimal 170 performance, LSTM neural networks are structured into the following layers: two input layers, one LSTM 171 hidden layers consisting of 50 neurons each, and an output layer. 2.4. Bi-directional long short-term memory (Bi-LSTM) 148 The optimum CNN consists of two input layers, 162 one convolutional layer with 32 neurons followed by a flat layer, a dense layer with 64 neurons, and an 163 output layer. For the best model fit and optimization, mean square error and Adam were used. For a simple 164 RNN, the number of hidden neurons in the hidden layers was investigated in the range of 2 to 40 using trial 165 and error approach, the appropriate value of hidden neuron was determined to be 20 and 8 for the two 166 hidden layers, respectively. The optimum RNN model consists of two input layers, a simple RNN hidden 167 layer with 20 neurons followed by a dense layer with 8 neurons, and an output layer. In each hidden layer, 168 ReLU (rectified linear unit) was used as the activation function. In particular, "mean square error" and 169 "rmsprop" were utilized in the processes of model fitness and optimization, respectively. To achieve optimal 170 performance, LSTM neural networks are structured into the following layers: two input layers, one LSTM 171 hidden layers consisting of 50 neurons each, and an output layer. Similarly, the optimal BI-LSTM network 172 consist of a two-input layer, one hidden BI-LSTM layer with 64 neurons, and one output layer. Notably, 173 the 'sigmoid' function was utilized in each hidden layer, while the Adam and mean squared errors were used 174 for model fitness and optimization, respectively, in both of the models. It is also noted that, different epoch 175 numbers of 100, 300, and 500 were tested in each run of the LSTM and BI-LSTM models, with the optimum 176 epoch found to be 500. 177 Table 1. Parametric configuration of the developed models 178 Model Optimum model configuration CNN 1D convolutional layer, flatten layer, dense layer, learning rate = 0.0001 batch size = 10, epoch = 500 RNN 20 hidden neurons in simple RNN layer, 8 hidden neurons in dense layer, input shape = (2,1), learning rate = 0.0001, batch size = 16, epoch = 500 LSTM 100 hidden neurons, input shape = (2,1), learning rate = 0.01, batch size = 15, epoch = 500 BI-LSTM 64 hidden neurons, input shape = (2,1), learning rate = 0.01, batch size = 15, epoch = 500 5 https://doi.org/10.5194/gmd-2023-62 Preprint. Discussion started: 12 April 2023 c⃝Author(s) 2023. CC BY 4.0 License. 2.4. Bi-directional long short-term memory (Bi-LSTM) 148 179 To assess the accuracy of the proposed models, different statistical indices were used. The accuracy of the 180 proposed models in term of the correlation between measured and estimated values was evaluated using 181 the coefficient of determination (R2), where 1 is the best, and Nash-Sutcliffe efficiency (NAF), where 100 182 is the best. In addition, the model errors were evaluated using root mean square error (RMSE); where 0 is 183 the best, mean absolute error (MAE), where 0 is the best, and mean bias error (MBE), where 0 is the best. 184 Furthermore, percentage error (PE) is applied to measure the accuracy of the proposed models in error 185 terms, 0 is the best, and the overall performance of models is tested using the performance index (PI), where 186 2 is the best. These indices are presented as follows: 187 𝑅2 = ∑ (𝑍𝑖−𝑍𝑚𝑒𝑎𝑛)2 𝑁 𝑖=1 −∑ (𝑍𝑖−𝑍𝑝𝑖)2 𝑁 𝑖=1 ∑ (𝑍𝑖−𝑍𝑚𝑒𝑎𝑛)2 𝑁 𝑖=1 (8) 188 𝑉𝐴𝐹= 100 × (1 − 𝑣𝑎𝑟(𝑍𝑖−𝑍𝑝𝑖) 𝑣𝑎𝑟(𝑍𝑖) ) (9) 189 𝑅𝑀𝑆𝐸= √∑ (𝑍𝑖−𝑍𝑝𝑖)2 𝑁 𝑖=1 𝑁 (10) 190 𝑀𝐴𝐸= ∑ |(𝑍𝑖−𝑍𝑝𝑖)| 𝑁 𝑖=1 𝑁 (11) 191 𝑀𝐵𝐸= 1 𝑁∑ (𝑍𝑖−𝑍𝑝𝑖) 𝑁 𝑖=1 (12) 192 𝑃𝐼= 𝑎𝑑𝑗. 𝑅2 + (0.01 × 𝑉𝐴𝐹) −𝑅𝑀𝑆𝐸 (13) 193 𝑃𝐸= 100 × 𝑅𝑀𝑆𝐸 𝑍𝑚𝑎𝑥−𝑍𝑚𝑖𝑛 (14) 194 𝑅2 = ∑ (𝑍𝑖−𝑍𝑚𝑒𝑎𝑛)2 𝑁 𝑖=1 −∑ (𝑍𝑖−𝑍𝑝𝑖)2 𝑁 𝑖=1 ∑ (𝑍𝑖−𝑍𝑚𝑒𝑎𝑛)2 𝑁 𝑖=1 (8) 188 𝑉𝐴𝐹= 100 × (1 − 𝑣𝑎𝑟(𝑍𝑖−𝑍𝑝𝑖) 𝑣𝑎𝑟(𝑍𝑖) ) (9) 189 𝑅𝑀𝑆𝐸= √∑ (𝑍𝑖−𝑍𝑝𝑖)2 𝑁 𝑖=1 𝑁 (10) 190 𝑀𝐴𝐸= ∑ |(𝑍𝑖−𝑍𝑝𝑖)| 𝑁 𝑖=1 𝑁 (11) 191 𝑀𝐵𝐸= 1 𝑁∑ (𝑍𝑖−𝑍𝑝𝑖) 𝑁 𝑖=1 (12) 192 𝑃𝐼= 𝑎𝑑𝑗. 𝑅2 + (0.01 × 𝑉𝐴𝐹) −𝑅𝑀𝑆𝐸 (13) 193 𝑃𝐸= 100 × 𝑅𝑀𝑆𝐸 𝑍𝑚𝑎𝑥−𝑍𝑚𝑖𝑛 (14) 194 𝑅2 = ∑ (𝑍𝑖−𝑍𝑚𝑒𝑎𝑛)2 𝑁 𝑖=1 −∑ (𝑍𝑖−𝑍𝑝𝑖)2 𝑁 𝑖=1 ∑ (𝑍𝑖−𝑍𝑚𝑒𝑎𝑛)2 𝑁 𝑖=1 (8) 188 𝑉𝐴𝐹= 100 × (1 − 𝑣𝑎𝑟(𝑍𝑖−𝑍𝑝𝑖) 𝑣𝑎𝑟(𝑍𝑖) ) (9) 189 𝑅𝑀𝑆𝐸= √∑ (𝑍𝑖−𝑍𝑝𝑖)2 𝑁 𝑖=1 𝑁 (10) 190 𝑀𝐴𝐸= ∑ |(𝑍𝑖−𝑍𝑝𝑖)| 𝑁 𝑖=1 𝑁 (11) 191 𝑀𝐵𝐸= 1 𝑁∑ (𝑍𝑖−𝑍𝑝𝑖) 𝑁 𝑖=1 (12) 192 𝑃𝐼= 𝑎𝑑𝑗. 𝑅2 + (0.01 × 𝑉𝐴𝐹) −𝑅𝑀𝑆𝐸 (13) 193 𝑃𝐸= 100 × 𝑅𝑀𝑆𝐸 𝑍𝑚𝑎𝑥−𝑍𝑚𝑖𝑛 (14) 194 = 𝑎𝑑𝑗. 𝑅2 + (0.01 × 𝑉𝐴𝐹) −𝑅𝑀𝑆𝐸 (13) = 100 × 𝑅𝑀𝑆𝐸 𝑍𝑚𝑎𝑥−𝑍𝑚𝑖𝑛 (14) (14) Where, 𝑍𝑖⁡𝑎𝑛𝑑⁡𝑍𝑝𝑖 represent the measured and predicted levelling, 𝑧𝑚𝑒𝑎𝑛, 𝑧𝑚𝑎𝑥, 𝑎𝑛𝑑⁡𝑧𝑚𝑖𝑛 are the average, 195 maximum and minimum, respectively, of measured values, 𝑎𝑑𝑗. 𝑅2 is the adjustment R2, and N is the 196 number of the data sample. 2.4. Bi-directional long short-term memory (Bi-LSTM) 148 All the 219 benchmarks that presented a standard deviation of more than 1 cm were removed from the network, leaving 220 229 benchmarks used in the ground level observations. 221 After estimating the corrected reduced levels of the selected benchmarks, they were used as a reference for 222 Figure 3. Data processing and modeling flowchart Figure 3. Data processing and modeling flowchart 2.4. Bi-directional long short-term memory (Bi-LSTM) 148 197 Where, 𝑍𝑖⁡𝑎𝑛𝑑⁡𝑍𝑝𝑖 represent the measured and predicted levelling, 𝑧𝑚𝑒𝑎𝑛, 𝑧𝑚𝑎𝑥, 𝑎𝑛𝑑⁡𝑧𝑚𝑖𝑛 are the average, 195 maximum and minimum, respectively, of measured values, 𝑎𝑑𝑗. 𝑅2 is the adjustment R2, and N is the 196 number of the data sample. 197 Figure 3 proposes the data processing and mapping in three stages. Data collection, adjustment, and 198 improvement are implemented in the first stage using the least squares method and PL benchmarks. E and 199 N are collected using GPS observation networks. Z was calculated at observed points using SL equipment. 200 The data were divided into training and testing stages. The training datasets were used to design the 201 proposed models in the second stage. In the last stage, training and testing datasets were used to assess the 202 performance of the proposed models. In addition, the whole datasets were used to validate the best-fit 203 model. Also, grids of 500 m were generated to map the ground level of the study area. 204 205 6 6 https://doi.org/10.5194/gmd-2023-62 Preprint. Discussion started: 12 April 2023 c⃝Author(s) 2023. CC BY 4.0 License. Figure 3. Data processing and modeling flowchart 206 3. Data collection 207 The ground level observations were collected in 2019 for a national Egyptian project that aims at the full 208 rehabilitation of the sanitary networks of the Egyptian small cities. The Sokkia B40 automatic level device 209 was utilized to measure elevations, and the benchmarks were connected by paths to form a closed network. 210 The corrections for the measurements were estimated using the Least Squares method. The observations 211 were carried out by a professional team of surveyors under the management of a consulting engineering 212 team. Figure 4 shows the study area, Manzalla region, and distribution of levelling points. The project 213 started by fixing more than 250 benchmarks covering the whole study region. Then these benchmarks were 214 connected using a full, precise leveling network, which was observed with great care by professional 215 surveyors and calibrated spirit level instruments. The network leveling observations were analyzed, filtered, 216 and corrected using the main principles of random error theory and rejection of outlier observations. Then, 217 the precise leveling network was corrected using the least squares method, which presented an estimated 218 standard deviation of nearly 6 millimeters for the estimated observations of the benchmarks. 3. Data collection The ground level observations were collected in 2019 for a national Egyptian project that aims at the full 208 rehabilitation of the sanitary networks of the Egyptian small cities. The Sokkia B40 automatic level device 209 was utilized to measure elevations, and the benchmarks were connected by paths to form a closed network. 210 The corrections for the measurements were estimated using the Least Squares method. The observations 211 were carried out by a professional team of surveyors under the management of a consulting engineering 212 team. Figure 4 shows the study area, Manzalla region, and distribution of levelling points. The project 213 started by fixing more than 250 benchmarks covering the whole study region. Then these benchmarks were 214 connected using a full, precise leveling network, which was observed with great care by professional 215 surveyors and calibrated spirit level instruments. The network leveling observations were analyzed, filtered, 216 and corrected using the main principles of random error theory and rejection of outlier observations. Then, 217 the precise leveling network was corrected using the least squares method, which presented an estimated 218 standard deviation of nearly 6 millimeters for the estimated observations of the benchmarks. All the 219 benchmarks that presented a standard deviation of more than 1 cm were removed from the network, leaving 220 229 benchmarks used in the ground level observations. 221 After estimating the corrected reduced levels of the selected benchmarks, they were used as a reference for 222 ground leveling observations which were conducted along the longitudinal center of every street in the 223 After estimating the corrected reduced levels of the selected benchmarks, they were used as a reference for 222 ground leveling observations, which were conducted along the longitudinal center of every street in the 223 study region with spacing ranging between 10 and 20 meters. The ground level observations were collected, 224 analyzed, and filtered to remove any blunder observations. 225 7 https://doi.org/10.5194/gmd-2023-62 Preprint. Discussion started: 12 April 2023 c⃝Author(s) 2023. CC BY 4.0 License. https://doi.org/10.5194/gmd-2023-62 Preprint. Discussion started: 12 April 2023 c⃝Author(s) 2023. CC BY 4.0 License. Figure 4. Study area and levelling points (a) study location, (b) leveling points and routes (Images resources from Esri) Figure 4. Study area and levelling points (a) study location, (b) leveling points and routes (Images resources from Esri) 6 226 Figure 5 and Table 1 present the data collection evaluation. 3. Data collection histogram of trend data used, and the normal 227 distribution of data used. The mean (M), maximum (MX), minimum (MN), standard deviation (STDEV), 228 and correlation (Corr) between input variables (E and N) and output variables (Z) are presented in Table 1. 229 The data distribution is shown to be non- normal. Negative and positive correlations between E and N and 230 Z, respectively, are observed. The statistical evaluation and data distribution show there is a nonlinear 231 correlation between Z and E,N. This indicates that a non-linear relationship between the input and output 232 8 https://doi.org/10.5194/gmd-2023-62 Preprint. Discussion started: 12 April 2023 c⃝Author(s) 2023. CC BY 4.0 License. variables can be detected, which is advantageous for using deep learning approaches in modeling the ground 233 levels. 234 235 Figure 5. Histogram and normal distribution of data used Table 1. Statistical evaluation of measured datasets 236 Variables E N Z M 399952.067 3447484.489 2.023 MX 403979.133 3451633.725 6.640 MN 393723.542 3444154.308 -2.939 STDEV 3089.666 1558.468 0.876 Corr -0.394 0.218 1.000 237 4. Results and Discussion 238 Figure 6 and Table 2 present the performance evaluations of the proposed models. The rank of the proposed 239 models is presented in Table 2. A high score value indicates the best performance. In the training stage, 240 LSTM outperformed other deep learning techniques. The correlation between measured and predicted 241 levels for LSTM is shown to be high, R2 and VAF are 0.99 and 99%, respectively. The estimation error of 242 the LSTM model is shown to be low: RMSE = 8.0 cm, MAE = 7.2 cm, and MBE = -2 cm. The overall 243 performance of LSTM is the best compared to other models PI = 1.9, and the percentage of the model error 244 is 0.84%. The rank of LSTM is 26, followed by BI-LSTM, rank = 22. The model followed in modeling the 245 leveling is BI-LSMT with PI=1.67 and PE = 2.18%; while the worst model is shown to be the CNN model. 246 From Figure 6, it can be seen that the scatter plot of LSTM is very close to the best fitting line (dashed line), 247 while the variation around the best fitting line is high for CNN and RNN. 248 As a result, in the testing stage, the LSTM model outperformed other models in all statistical indices. 3. Data collection The 249 rank evaluation of the proposed models showed that LSTM has a high rank compared to other models. 250 CNN was shown to be better than RNN at this stage. BI-LSTM still followed LSTM in the testing stage to 251 model the ground levels. From Figure 6, it can be seen that the scatter plot of LSTM is very close to the 252 best fitting line, while the variation around the best fitting line is high for CNN and RNN. The performance 253 of BI-LSTM is shown to be acceptable in the testing stage, rank = 21; however, LSTM performance 254 achieved a high rank (28) in estimating ground levels. 255 variables can be detected, which is advantageous for using deep learning approaches in modeling the ground 233 levels. 234 235 Figure 5. Histogram and normal distribution of data used Table 1. Statistical evaluation of measured datasets 236 Variables E N Z M 399952.067 3447484.489 2.023 MX 403979.133 3451633.725 6.640 MN 393723.542 3444154.308 -2.939 STDEV 3089.666 1558.468 0.876 Corr -0.394 0.218 1.000 237 Figure 5. Histogram and normal distribution of data used 9 https://doi.org/10.5194/gmd-2023-62 Preprint. Discussion started: 12 April 2023 c⃝Author(s) 2023. CC BY 4.0 License. Figure 6. Training and testing scatter plot of predicted and measured leveling 10 Figure 6. Training and testing scatter plot of predicted and measured leveling Table 2. Models’ performance assessments in the training and testing stages 256 Training R2 VAF PI RMSE MAE MBE PE Total score CNN Value 0.614 60.807 0.840 0.382 0.426 -0.189 3.986 7 Ranke 1 1 1 1 1 1 1 RNN Value 0.890 89.003 1.510 0.270 0.239 -0.015 2.819 15 Ranke 2 2 2 2 2 3 2 LSTM Value 0.991 99.145 1.903 0.080 0.072 -0.020 0.839 26 Ranke 4 4 4 4 4 2 4 BI-LSTM Value 0.940 93.961 1.670 0.209 0.126 -0.001 2.180 22 Ranke 3 3 3 3 3 4 3 Testing CNN Value 0.645 63.232 0.905 0.372 0.429 -0.186 4.685 13 Ranke 2 2 2 2 2 1 2 RNN Value 0.516 48.580 0.439 0.562 0.557 0.053 7.082 8 Ranke 1 1 1 1 1 2 1 LSTM Value 0.993 99.326 1.912 0.074 0.062 -0.012 0.936 28 Ranke 4 4 4 4 4 4 4 BI-LSTM Value 0.978 97.840 1.825 0.132 0.100 -0.014 1.663 21 Ranke 3 3 3 3 3 3 3 Figure 6. 3. Data collection Training and testing scatter plot of predicted and measured leveling Table 2. Models’ performance assessments in the training and testing stages Figure 6. Training and testing scatter plot of predicted and measured leveling Table 2. Models’ performance assessments in the training and testing stages Figure 6. Training and testing scatter plot of predicted and measured leveling 10 10 https://doi.org/10.5194/gmd-2023-62 Preprint. Discussion started: 12 April 2023 c⃝Author(s) 2023. CC BY 4.0 License. 257 In addition, the performances, of LSTM and BI-LSTM models in modeling ground variation levels are 258 presented in Figure 7 in the testing phase. From the figure, it can be seen that the variation of errors for both 259 models are small. The error ranges of LSTM and BI-LSTM are (-0.13 to 0.07) and (-1.09 to 0.26) m, 260 respectively. Thus, both models can be used to estimate levelling. 261 Figure 7. Modeling performance of LSTM and BI-LSTM models in the testing stage In addition, the performances, of LSTM and BI-LSTM models in modeling ground variation levels are 258 presented in Figure 7 in the testing phase. From the figure, it can be seen that the variation of errors for both 259 models are small. The error ranges of LSTM and BI-LSTM are (-0.13 to 0.07) and (-1.09 to 0.26) m, 260 respectively. Thus, both models can be used to estimate levelling. 261 respectively. Thus, both models can be used to estimate levelling. 261 Figure 7. Modeling performance of LSTM and BI-LSTM models in the testing stage 262 For more investigation, a visualization plot is used to assess the performance of the proposed models. The 263 Taylor diagram (Figure 8.a) and boxplot (Figure 8.b) are presented to evaluate overall performance and 264 model errors, respectively. Taylor's diagram is a two-dimensional diagram that provides a comparative 265 review of models in terms of R-value, root mean square deviation (RMSD), and ratio of standard deviation 266 between measured and predicted values. The best model is the one closest to the reference point. The details 267 of the Taylor diagram can be found in (Taylor 2005). Here, test datasets are used to assess the proposed 268 models based on untuned datasets of models. Taylor's diagram shows the overall performance of LSTM in 269 modeling ground level is better than that of BI-LSTM, CNN, and RNN, respectively. 3. Data collection The accuracy of BI- 270 LSTM is close to that of LSTM, and it can be used for ground level estimation. However, boxplots show 271 there are outliers that can be observed with BI-LSTM. In addition, the model error range of LSTM is very 272 Figure 7. Modeling performance of LSTM and BI-LSTM models in the testing stage 262 For more investigation, a visualization plot is used to assess the performance of the proposed models. The 263 Taylor diagram (Figure 8.a) and boxplot (Figure 8.b) are presented to evaluate overall performance and 264 model errors, respectively. Taylor's diagram is a two-dimensional diagram that provides a comparative 265 review of models in terms of R-value, root mean square deviation (RMSD), and ratio of standard deviation 266 between measured and predicted values. The best model is the one closest to the reference point. The details 267 of the Taylor diagram can be found in (Taylor 2005). Here, test datasets are used to assess the proposed 268 models based on untuned datasets of models. Taylor's diagram shows the overall performance of LSTM in 269 modeling ground level is better than that of BI-LSTM, CNN, and RNN, respectively. The accuracy of BI- 270 LSTM is close to that of LSTM, and it can be used for ground level estimation. However, boxplots show 271 there are outliers that can be observed with BI-LSTM. In addition, the model error range of LSTM is very 272 11 https://doi.org/10.5194/gmd-2023-62 Preprint. Discussion started: 12 April 2023 c⃝Author(s) 2023. CC BY 4.0 License. small, and the interquartile range of LSTM is very small compared to other models. Although the CNN 273 model outperforms the RNN model in terms of overall performance, it has a high number of outliers. 274 Boxplot obviously shows the LSTM model can be accurately used in ground level estimation. 275 small, and the interquartile range of LSTM is very small compared to other models. Although the CNN 273 model outperforms the RNN model in terms of overall performance, it has a high number of outliers. 274 Boxplot obviously shows the LSTM model can be accurately used in ground level estimation. 275 76 (a) (b) Figure 8. Visualization analysis of the proposed models (a) Taylor diagram (b) boxplot 77 Figure 9 shows the map estimation of the study area for ground levels and the error of the estimation levels. 3. Data collection 78 The error is the difference between levels of mapping and measurements. From the map, it can be seen that 79 the ground level is smooth and slopes from 0 to 6 m in one direction. From the measured errors, it can be 80 seen that the absolute mean error of the estimated ground levels is 0.187 cm, and the standard deviation of 81 error is 0.666 m. The error distribution is roughly normal, and the majority of the confidence in the model 82 error falls within the 95% confidence interval. This indicates that the estimated levels are acceptable, and 83 that LSTM can be accurately applied to estimate the ground level of the study area. These results reveal the 84 (a) (a) (b) Fi 8 Vi li ti l i f th d d l ( ) T l di (b) b l t (b) Figure 8. Visualization analysis of the proposed models (a) Taylor diagram (b) boxplot gure 9 shows the map estimation of the study area for ground levels and the error of the estimation levels. Figure 9 shows the map estimation of the study area for ground levels and the error of the estimation levels. 278 The error is the difference between levels of mapping and measurements. From the map, it can be seen that 279 the ground level is smooth and slopes from 0 to 6 m in one direction. From the measured errors, it can be 280 seen that the absolute mean error of the estimated ground levels is 0.187 cm, and the standard deviation of 281 error is 0.666 m. The error distribution is roughly normal, and the majority of the confidence in the model 282 error falls within the 95% confidence interval. This indicates that the estimated levels are acceptable, and 283 that LSTM can be accurately applied to estimate the ground level of the study area. These results reveal the 284 12 https://doi.org/10.5194/gmd-2023-62 Preprint. Discussion started: 12 April 2023 c⃝Author(s) 2023. CC BY 4.0 License. proposed model is accurate in estimating ground level, and LSTM can be applied in similar areas to decrease 285 the cost and time of SL field works. 286 287 (a) (b) Figure 9. Mapping of the ground level, (a) contour map and (b) model error 288 5. 3. Data collection Conclusions 289 In the current study, the applicability of using deep learning techniques for mapping ground relative 290 levelling from spirit leveling (SL) measurements was investigated. Convolution Neural Network (CNN), 291 Recurrent Neural Networks (RNN), Long Short-Term Memory (LSTM), and bi-directional LSTM (BI- 292 LSTM) were developed and compared to estimate the leveling through SL measurements of Manzalla 293 region, Egypt. 3253 datasets leveling points of SL including 229 benchmark points of precise levelling (PL) 294 were used to map an area of about 77 Km2 and to verify the proposed models. 295 In a comparative study, the proposed models showed overall performances of RNN, BI-LSTM, and LSTM 296 models of 1.51, 1.67, and 1.90, respectively, in the training stage. The overall performance of CNN is 0.91, 297 while the overall performance (PI) of the BI-LSTM and LSTM models is 1.82 and 1.91, respectively, in 298 the testing stage. The accuracy of BI-LSTM and LSTM models in estimating ground level reaches up to 299 98.5% and 99% in terms of model error (PE). The visualization evaluation of the proposed models showed 300 LSTM outperformed other models in terms of the Taylor diagram and box plot. Thus, the LSTM model can 301 be considered an accurate soft computing model that can be used to estimate the ground level of the study 302 area. With the same concepts, it can be applied in the same regions. LSTM is applied to map the ground 303 level of the study area, and the results show that the estimated accuracy of the ground level of the study 304 area is 0.187 cm + 0.666 m. The error distribution of the model error is significantly within the 95% interval. 305 These results reveal the proposed model is accurate in estimating ground level, and LSTM can be applied 306 in similar areas to decrease the cost and time of SL field works. 307 308 proposed model is accurate in estimating ground level, and LSTM can be applied in similar areas to decrease 285 the cost and time of SL field works. 286 proposed model is accurate in estimating ground level, and LSTM can be applied in similar areas to decrease 285 the cost and time of SL field works. 286 proposed model is accurate in estimating ground level, and LSTM can be applied in similar areas to decrease 285 the cost and time of SL field works. 3. Data collection 286 287 287 (a) (b) Figure 9. Mapping of the ground level, (a) contour map and (b) model error 288 (b) (a) Figure 9. Mapping of the ground level, (a) contour map and (b) model error In a comparative study, the proposed models showed overall performances of RNN, BI-LSTM, and LSTM 296 models of 1.51, 1.67, and 1.90, respectively, in the training stage. The overall performance of CNN is 0.91, 297 while the overall performance (PI) of the BI-LSTM and LSTM models is 1.82 and 1.91, respectively, in 298 the testing stage. The accuracy of BI-LSTM and LSTM models in estimating ground level reaches up to 299 98.5% and 99% in terms of model error (PE). The visualization evaluation of the proposed models showed 300 LSTM outperformed other models in terms of the Taylor diagram and box plot. Thus, the LSTM model can 301 be considered an accurate soft computing model that can be used to estimate the ground level of the study 302 area. With the same concepts, it can be applied in the same regions. LSTM is applied to map the ground 303 level of the study area, and the results show that the estimated accuracy of the ground level of the study 304 area is 0.187 cm + 0.666 m. The error distribution of the model error is significantly within the 95% interval. 305 These results reveal the proposed model is accurate in estimating ground level, and LSTM can be applied 306 in similar areas to decrease the cost and time of SL field works. 307 13 13 https://doi.org/10.5194/gmd-2023-62 Preprint. Discussion started: 12 April 2023 c⃝Author(s) 2023. CC BY 4.0 License. Author contributions: FZ, MRK, and TE conceptualized the study, collected, and analyze the data, 312 evaluated the results, and wrote the manuscript. MRK, PS, and MSS visualize the data, modeling designed 313 and evaluated, and revised the manuscript. MRK and JWH revised the final form. 314 315 Competing interests: The contact author has declared that none of the authors has any competing interests. 316 317 Acknowledgements: Authors are grateful for the Sustainable Rural Sanitation Services Program (SRSSP) 318 in Dakahlia Governorate for providing ground level observations. 319 320 Financial support: This work is supported by the Korea Agency for Infrastructure Technology 321 Advancement (KAIA) grant funded by the Ministry of Land, Infrastructure and Transport (Grant RS-2022- 322 00143541). 3. Data collection 323 324 Data availability: The used data in this study can be found in the supplementary materials. 325 326 327 References 328 Ahmed EL-Mowafy (2004) Surveying with GPS for Construction Works Using the National RTK Reference 329 Network and Precise Geoid Models. In: 1st FIG International Symposium on Engineering Surveys 330 for Construction Works and Structural Engineering 331 Amalou I, Mouhni N, Abdali A (2022) Multivariate time series prediction by RNN architectures for energy 332 consumption forecasting. Energy Reports 8:1084–1091. 333 https://doi.org/10.1016/j.egyr.2022.07.139 334 Apaydin H, Feizi H, Sattari MT, et al (2020) Comparative analysis of recurrent neural network 335 architectures for reservoir inflow forecasting. Water (Switzerland) 12:. 336 https://doi.org/10.3390/w12051500 337 Asenso-Gyambibi D, Lamkai N, Peprah M, et al (2022) Novel Ellipsoidal Heights Predictive Models Based 338 on Artificial Intelligence Training Algorithms and Classical Regression Models Techniques: A Case 339 Study in the Greater Kumasi Metropolitan Area Local Geodetic Reference Network, Kumasi, Ghana. 340 International Journal of Earth Sciences Knowledge and Applications 4:493–515 341 CDT (2012) Global Positioning System (GPS) Survey Specifications. California 342 Erol B, Erol S (2013) Learning-based computing techniques in geoid modeling for precise height 343 transformation. Comput Geosci 52:95–107. 344 https://doi.org/https://doi.org/10.1016/j.cageo.2012.09.010 345 Graves A, Schmidhuber J (2005) Framewise phoneme classification with bidirectional LSTM and other 346 neural network architectures. Neural Networks 18:602–610. 347 https://doi.org/https://doi.org/10.1016/j.neunet.2005.06.042 348 14 14 https://doi.org/10.5194/gmd-2023-62 Preprint. Discussion started: 12 April 2023 c⃝Author(s) 2023. CC BY 4.0 License. 15 Hang R, Liu Q, Hong D, Ghamisi P (2019) Cascaded Recurrent Neural Networks for Hyperspectral Image 349 Classification. IEEE Transactions on Geoscience and Remote Sensing 57:5384–5394. 350 https://doi.org/10.1109/TGRS.2019.2899129 351 Hochreiter S, Schmidhuber J (1997) Long Short-Term Memory. Neural Comput 9:1735–1780. 352 https://doi.org/10.1162/neco.1997.9.8.1735 353 IHO (2011) Positioning. https://iho.int/uploads/user/pubs/cb/c-13/english/C-13_Chapter_2.pdf. 354 Accessed 19 Feb 2023 355 Jang Y, Ahn Y, Kim HY (2019) Estimating Compressive Strength of Concrete Using Deep Convolutional 356 Neural Networks with Digital Microscope Images. Journal of Computing in Civil Engineering 33:1– 357 11. https://doi.org/10.1061/(ASCE)CP.1943-5487.0000837 358 Janos D, Kuras P, Ortyl Ł (2022) Evaluation of low-cost RTK GNSS receiver in motion under demanding 359 conditions. Measurement 201:111647. 360 https://doi.org/https://doi.org/10.1016/j.measurement.2022.111647 361 Kaloop MR, Kumar D, Zarzoura F, et al (2020a) A wavelet - Particle swarm optimization - Extreme 362 learning machine hybrid modeling for significant wave height prediction. Ocean Engineering 363 213:107777. 3. Data collection https://doi.org/https://doi.org/10.1016/j.oceaneng.2020.107777 364 Kaloop MR, Rabah M, Elnabwy M (2016) Sea Level Change Analysis and Models Identification Based on 365 Short Tidal Gauge Measurements in Alexandria, Egypt. Marine Geodesy 39:. 366 https://doi.org/10.1080/01490419.2015.1134735 367 Kaloop MR, Rabah M, Hu JW, Zaki A (2018) Using advanced soft computing techniques for regional 368 shoreline geoid model estimation and evaluation. Marine Georesources & Geotechnology 36:688– 369 697. https://doi.org/10.1080/1064119X.2017.1370622 370 Kaloop MR, Zaki A, Al-Ajami H, Rabah M (2019) Optimizing Local Geoid Undulation Model using 371 GPS/Levelling Measurements and Heuristic Regression Approaches. Survey Review 1–11. 372 https://doi.org/10.1080/00396265.2019.1665615 373 Kaloop MR, Zaki A, Al-Ajami H, Rabah M (2020b) Optimizing Local Geoid Undulation Model using 374 GPS/Levelling Measurements and Heuristic Regression Approaches. Survey Review 52:. 375 https://doi.org/10.1080/00396265.2019.1665615 376 Karila K, Karjalainen M, Hyyppä J, et al (2013) A comparison of precise leveling and Persistent Scatterer 377 SAR Interferometry for building subsidence rate measurement. ISPRS Int J Geoinf 2:797–816. 378 https://doi.org/10.3390/ijgi2030797 379 Kemboi KE (2016) ESTIMATION OF ORTHOMETRIC HEIGHT USING EGM2008 AND GPS OVER NAIROBI 380 COUNTY AND ITS ENVIRONS Determination of an Optimal Trunk Sewer-line Route for Kikuyu Town 381 Using Geospatial Technologies View project Geoid modelling and height systems View project 382 15 https://doi.org/10.5194/gmd-2023-62 Preprint. Discussion started: 12 April 2023 c⃝Author(s) 2023. CC BY 4.0 License. LSC (2018) Spirit Leveling . In: USGS 383 ( ) p g Miky Y, Kaloop MR, Elnabwy MT, et al (2021) A Recurrent-Cascade-Neural network- nonlinear 384 autoregressive networks with exogenous inputs (NARX) approach for long-term time-series 385 prediction of wave height based on wave characteristics measurements. Ocean Engineering 386 240:109958. https://doi.org/https://doi.org/10.1016/j.oceaneng.2021.109958 387 Minuzzi FC, Farina L (2023) A deep learning approach to predict significant wave height using long short- 388 term memory. Ocean Model (Oxf) 181:102151. 389 https://doi.org/https://doi.org/10.1016/j.ocemod.2022.102151 390 Oh BK, Glisic B, Kim Y, Park HS (2019) Convolutional neural network‐based wind‐induced response 391 estimation model for tall buildings. Computer-Aided Civil and Infrastructure Engineering 34:843– 392 858. https://doi.org/10.1111/mice.12476 393 Rabah M, Kaloop M (2013) The use of minimum curvature surface technique in geoid computation 394 processing of Egypt. Arabian Journal of Geosciences 6:. https://doi.org/10.1007/s12517-011-0418- 395 0 396 Rußwurm M, Körner M (2017) Multi-temporal land cover classification with long short-term memory 397 neural networks. In: International Archives of the Photogrammetry, Remote Sensing and Spatial 398 Information Sciences - ISPRS Archives. 3. Data collection International Society for Photogrammetry and Remote 399 Sensing, pp 551–558 400 Shanker KC, Acharya TD (2022) Advancements of Geodetic Activities in Nepal: A Review on Pre-and Post- 401 2015 Gorkha Earthquake Eras with Future Directions. Remote Sens (Basel) 14 402 Sinha A, Abernathey R (2021) Estimating Ocean Surface Currents With Machine Learning. Front Mar Sci 403 8:. https://doi.org/10.3389/fmars.2021.672477 404 Sorkhabi OM, Milani M, Seyed Alizadeh SM (2022) Investigating the Efficiency of Deep Learning Methods 405 in Estimating GPS Geodetic Velocity. Earth and Space Science 9:. 406 https://doi.org/10.1029/2021EA002202 407 Sorkhabi OM, Propagation AB, Neural A, Bpann N (2015) Geoid Determination Based on Log Sigmoid 408 Function of Artificial Neural Networks : ( A case Study : Iran ). Journal of Artificial Intelligence in 409 Electrical Engineering 3:18–24 410 Sun Z, Di L, Fang H (2019) Using long short-term memory recurrent neural network in land cover 411 classification on Landsat and Cropland data layer time series. Int J Remote Sens 40:593–614. 412 https://doi.org/10.1080/01431161.2018.1516313 413 Taylor KE (2005) Taylor Diagram Primer 414 16 16 https://doi.org/10.5194/gmd-2023-62 Preprint. Discussion started: 12 April 2023 c⃝Author(s) 2023. CC BY 4.0 License. Tütüncü K, Şahman MA, Tuşat E (2021) A hybrid binary grey wolf optimizer for selection and reduction 415 of reference points with extreme learning machine approach on local GNSS/leveling geoid 416 determination. Appl Soft Comput 108:107444. 417 https://doi.org/https://doi.org/10.1016/j.asoc.2021.107444 418 Veronez MR, de Souza SF, Matsuoka MT, et al (2011) Regional mapping of the geoid using GNSS (GPS) 419 measurements and an artificial neural network. Remote Sens (Basel) 3:668–683. 420 https://doi.org/10.3390/rs3040668 421 Vinaykumar VN, Babu JA, Frnda J (2023) Optimal guidance whale optimization algorithm and hybrid 422 deep learning networks for land use land cover classification. EURASIP J Adv Signal Process 423 2023:13. https://doi.org/10.1186/s13634-023-00980-w 424 Wang J, Bretz M, Dewan MAA, Delavar MA (2022) Machine learning in modelling land-use and land 425 cover-change (LULCC): Current status, challenges and prospects. Science of The Total Environment 426 822:153559. https://doi.org/https://doi.org/10.1016/j.scitotenv.2022.153559 427 Wang S, Zhou J, Lei T, et al (2020) Estimating Land Surface Temperature from Satellite Passive 428 Microwave Observations with the Traditional Neural Network, Deep Belief Network, and 429 Convolutional Neural Network. Remote Sens (Basel) 12:2691. https://doi.org/10.3390/rs12172691 430 Yιlmaz M, Acar M, Ayan T, Arslan E (2006) Application of Fuzzy Logic Theory to Geoid Height 431 Determination. In: Kłopotek MA, Wierzchoń ST, Trojanowski K (eds) Intelligent Information 432 Processing and Web Mining. 3. Data collection Springer Berlin Heidelberg, Berlin, Heidelberg, pp 383–388 433 Zhang Y, Zhang C, Ma Q, et al (2022) Automatic prediction of shear wave velocity using convolutional 434 neural networks for different reservoirs in Ordos Basin. J Pet Sci Eng 208:. 435 https://doi.org/10.1016/j.petrol.2021.109252 436 Zhong D (1997) Robust estimation and optimal selection of polynomial parameters for the interpolation 437 of GPS geoid heights. J Geod 71:552–561. https://doi.org/10.1007/s001900050123 438 439 Zhong D (1997) Robust estimation and optimal selection of polynomial parameters for the interpolation 437 of GPS geoid heights. J Geod 71:552–561. https://doi.org/10.1007/s001900050123 438 439 17
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Loss to follow-up in a randomized controlled trial study for pediatric weight management (EPOC)
BMC pediatrics
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© The Author(s). 2016 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. * Correspondence: warschb@uni-potsdam.de 1Department of Psychology, University of Potsdam, Counseling Psychology, Potsdam University, Karl- Liebknecht- Str. 24/25, 14476 Potsdam, Germany Full list of author information is available at the end of the article Loss to follow-up in a randomized controlled trial study for pediatric weight management (EPOC) Petra Warschburger1* and Katja Kröller1,2 Warschburger and Kröller BMC Pediatrics (2016) 16:184 DOI 10.1186/s12887-016-0727-2 Warschburger and Kröller BMC Pediatrics (2016) 16:184 DOI 10.1186/s12887-016-0727-2 Abstract Background: Attrition is a serious problem in intervention studies. The current study analyzed the attrition rate during follow-up in a randomized controlled pediatric weight management program (EPOC study) within a tertiary care setting. Methods: Five hundred twenty-three parents and their 7–13-year-old children with obesity participated in the randomized controlled intervention trial. Follow-up data were assessed 6 and 12 months after the end of treatment. Attrition was defined as providing no objective weight data. Demographic and psychological baseline characteristics were used to predict attrition at 6- and 12-month follow-up using multivariate logistic regression analyses. Results: Objective weight data were available for 49.6 (67.0) % of the children 6 (12) months after the end of treatment. Completers and non-completers at the 6- and 12-month follow-up differed in the amount of weight loss during their inpatient stay, their initial BMI-SDS, educational level of the parents, and child’s quality of life and well- being. Additionally, completers supported their child more than non-completers, and at the 12-month follow-up, families with a more structured eating environment were less likely to drop out. On a multivariate level, only educational background and structure of the eating environment remained significant. Conclusions: The minor differences between the completers and the non-completers suggest that our retention strategies were successful. Further research should focus on prevention of attrition in families with a lower educational background. Trial registration: Current Controlled Trials ISRCTN24655766. Registered 06 September 2008, updated 16 May 2012. Trial registration: Current Controlled Trials ISRCTN24655766. Registered 06 September 2008, updated 16 May 2012. Keywords: Attrition Obesity Child Predictors Weight management trial Trial registration: Current Controlled Trials ISRCTN24655766. Registered Keywords: Attrition, Obesity, Child, Predictors, Weight management trial Demographic and weight data Parents were asked to provide demographic information such as age, family status and educational level (number of years spent in school) at the beginning of their child’s inpatient stay. In addition, all parents reported their own height and weight, as well as the respective data of their partners. Children were weighed in light underwear by a physician on a standard beam scale (accurate to 100 g) and measured using a calibrated stadiometer (accurate to 1 cm). Thereafter, a standardized BMI (BMI-SDS) for age and sex was calculated [19]. Several steps were taken to minimize loss to follow-up. To obtain objective weight data, we conducted a 6- and 12-month follow-up by contacting families and physicians by post. If families did not provide the weight data within 3 weeks, a re- minder was sent by post. For the 12-month follow-up, we also telephoned the families that had still not replied and encouraged them to visit their physician or a phar- macy in order to provide the data. As a final option, we offered them a home visit. Both families and physicians were reimbursed for returning the respective question- naire (50 and 25€, respectively). Other studies examined the determining factors for drop-out during treatment [9], with fairly inconclusive results, as almost no overlap was found between the in- dicators analyzed. Although some studies reported a higher attrition rate for those with a higher BMI z-score [10–13], others did not find a significant effect (n.s. [14, 15]), older age [10, 11, 13] (n.s. [14–16]), ethnic minority status [10, 14, 15] (n.s. [11, 16]), lower socioeconomic status (SES)/education (trend [17]; n.s. [12, 16]) or psy- chological problems [10, 13, 17] (n.s. [11, 12]). Consist- ently, no study reported gender effects [11–13, 15–17]. To be able to adequately interpret study results, it is crucial to achieve high retention rates in intervention re- search. Participants’ motivation to devote time and effort to filling in questionnaires or attending medical check- ups will decrease over time, and this may be particularly true when treatment takes place in inpatient facilities that are far from patients’ homes. Hence, knowledge re- garding predictors of attrition during follow-up in clin- ical trials is limited. Therefore, we analyzed the data of a large randomized controlled study (Empowering Parents of Obese Children – EPOC study) in order to examine which factors predicted failure to provide objective weight-related measurements. Demographic and weight data We hypothesized that parents with a lower educational background and Background confounding influences. Therefore, high attrition rates can cause a significant bias in the study. Such a bias might alter the characteristics of a sample and impede the comparability to the original sample. Moreover, the bias might alter the covariance of the variables included, possibly affecting outcomes or other correlated variables (as reviewed by Ahern [1]). Attrition is a serious problem in intervention studies, which can threaten reliability and validity for several rea- sons: First, when participants drop out of a study, ana- lyses are limited to a smaller sample, which can lead to insufficient statistical power. Second, although partici- pants may drop out for various reasons, some of these can be related to the outcome. Third, the drop-out pat- tern may differ between treatment groups, altering the random composition of the groups and leading to Reviewing the attrition rates in randomized controlled studies of chronic illness in childhood, Karlson and Rap- off [2] reported that on average, 37 % (range 0–75 %) re- fused to take part in the study at the beginning, 4 % (range 0–35 %) provided no baseline data, 20 % (range 0–54 %) no initial follow-up data, and 32 % (range 0– 59 %) no long-term follow-up data. The majority of the * Correspondence: warschb@uni-potsdam.de 1Department of Psychology, University of Potsdam, Counseling Psychology, Potsdam University, Karl- Liebknecht- Str. 24/25, 14476 Potsdam, Germany Full list of author information is available at the end of the article Warschburger and Kröller BMC Pediatrics (2016) 16:184 Page 2 of 9 children experiencing less success during treatment and higher psycho-social strain would return objective weight data less frequently. studies did not analyze differences between completers and non-completers. Collins et al. [3] assessed the effi- cacy of dietetic interventions for children with obesity. From the 37 randomized controlled trials (RCT) they ex- tracted, 26 included follow-up data (1 month to 10 years). Attrition rates during follow-up varied from 5 to 37 %. Only 9 studies reported efficacy data on the basis of an intention-to-treat analysis. Sample and procedure Written consent was obtained from parents of 7–13- year-old children with obesity to take part in the EPOC study examining the effects of supplementary parent training as part of the child’s inpatient obesity interven- tion. Inclusion and exclusion criteria are described in de- tail elsewhere [18]. The study was approved by the Ethics Committee of the University of Potsdam on 19 May 2006. In general, only a small number of studies have re- ported explicit loss at follow-up. In a recent family- focused intervention study [4], approximately 20 % of participants dropped out at the follow-up assessments. These children were significantly older and had a higher body mass index (BMI) z-score at baseline. This is in line with the findings of van den Aker et al. [5], who re- ported an attrition rate of 33 % at the 1-year follow-up, with drop-outs being older and less successful during treatment. McCallum et al. [6] stated that the children lost in follow-up were slightly heavier, and that their par- ents reported a lower quality of life for their children. Unfortunately, it was not reported whether these differ- ences were statistically significant. Hughes et al. [7] ob- served a 34.9–36.9 % loss during follow-up 12 months after the start of treatment, and did not report any demographic differences between completers and non- completers. This is in line with the data of Savoye et al. [8], who found no differences between completers and non-completers with respect to baseline characteristics (BMI, age, gender). y Children’s weight and height were measured by a physician, who was blind to the treatment group to which they were assigned, at different time periods: at baseline (beginning of the intervention), post- intervention and six and twelve months thereafter. In addition, parents and their children filled in a set of questionnaires. Table 1 provides a sample description of the study’s 523 children (274, 52.4 % girls) and their par- ents at baseline. Parental aspects p Parental quality of life was measured by the well- established SF12 [27], including physical and mental well-being. The parents’ perception of their support of their child was measured with a self-constructed instru- ment including aspects such as being a role model, and emotional and instrumental support. The postulated fac- tor structure was confirmed [24], showing acceptable re- liability values for the summarized scale (α = .80). The parental self-efficacy in changing family eating and activ- ity habits even in the face of problems or challenges was measured by a further self-constructed scale that in- cludes aspects of care-taking, personal changes made and social demands. The Cronbach’s α indicated a high reliability of the scale (α = .95). (HRQoL) was measured with the KID-KINDL-R [20]. The total score (including the 4 subscales ‘psychological well-being’, ‘self-esteem’, ‘family’ and ‘peers’) revealed an acceptable reliability value (α = .85) comparable with the original form (α = .70 [21]). The child’s weight-related quality of life (WRQoL) was measured with an estab- lished German instrument [22]. In line with previous validation values (α = .87 [23]), the reliability was good (α = .85). In addition, parents reported on the child’s food intake pertaining to ‘problematic’ (e.g., sweets, salty snacks, fast food and soft drinks) and ‘healthy’ (fruits, vegetables) food items on a 5-point scale (“never” – “sev- eral times a day”). Latent structure models confirmed the postulated factor structure [24]. The child’s eating behavior was measured with the FKE-KJ [22], which combines the 2 subscales ‘speed of eating’ (4 items) and ‘family eating environment’ (4 items). In accordance with previous evaluations, both scales showed an acceptable reliability within the current sample (α = .77 and .70, re- spectively). Furthermore, the child’s activity level, includ- ing media consumption and physical exercise, was assessed with an instrument from the KIGGS-study [25]. The instrument includes the mean duration (in hours) Child factors Since the results regarding the factors that influence the attrition rate in clinical trials are inconsistent, we ana- lyzed a wide range of child and parental factors. All data with the exception of the child’s self-efficacy are based on parent reports. The health-related quality of life Warschburger and Kröller BMC Pediatrics (2016) 16:184 Page 3 of 9 Page 3 of 9 Page 3 of 9 Table 1 Sample description of the total sample at baseline Children (n = 523) Sex female 52.4 % male 47.6 % Age (in years of age) 11.3 ± 1.29 (7–13) BMI- SDS (measured) 2.56 ± 0.39 (1.89–4.57) Weight classification obesea 57.2 % extremely obeseb 42.8 % Parents (n = 523) Age (in years of age) 40.56 ± 5.77 (25.94–58.78) Educational level (in years of school completed) 10.3 ± 1.40 (6–13) Family status relationship 68.8 % single 31.2 % BMI (self-reported in kg/m2) 29.19 ± 6.89 (14.10–59.06) Weight classification normal- or under-weightc 32.2 % overweightd 28.7 % obesee 39.1 % Note: BMI-SDS body mass index - standard deviation score a 97th percentile < BMI-SDS ≤99.5th percentile based on the classification by Kromeyer-Hauschild et al. [19] b BMI-SDS > 99th percentile c BMI ≤25 d 25 < BMI ≤30 e BMI > 30 Table 1 Sample description of the total sample at baseline Children (n = 523) of the child’s use of television, video or computers as well as physical activity assessed by a 5-point Likert- scale. We formed a summarized score indicating the overall media consumption and activity level during an entire week. The child’s psychosocial strain was mea- sured with the Strengths and Difficulties Questionnaire SDQ [26]. The sum score is made up of four subscales: ‘emotional problems’, ‘behavioral problems’, ‘peer prob- lems’ and ‘hyperactivity’. The scale showed good reliabil- ity (α = .84). Children assessed their own weight-related self-efficacy, answering the GW-SW-KJ [22], which in- cludes 24 items rated on a 5-point Likert scale. Previous reliability values (α = .89) were replicated in the current study (α = .89). All scales were transformed to a 0–100 scale. Statistical analyses y All statistical analyses were performed using SPSS 21.0. Attrition was defined as missing objective weight data at the 6- or 12-month follow-up. In the first step, we ana- lyzed univariate differences between completers and non-completers (Chi-square, (M)ANOVA) and in the second step, we used logistic regression analysis to ex- plore the variables that were associated with a higher risk of quitting the study on a multivariate level. For the logistic regression, variables were included stepwise: (1) demographic and inpatient stay-related aspects, (2) par- ental aspects, (3) the child’s psychosocial strain, and (4) secondary treatment outcomes, such as the child’s qual- ity of life and self-efficacy, as well as activity level, food intake and eating behavior. Differences between completers and non-completers Univariate differences between completers and non- completers at the 6-month follow-up are presented in Table 2. The children’s initial weight status and weight change during the inpatient stay differed significantly be- tween completers and non-completers, indicating a higher initial weight status and a lower weight loss in non-completers. These differences between completers and non- completers at the 6-month follow-up were also observed in the one-year follow-up (see Table 3). In addition, there were significant differences regarding the parents’ educational level (completers had a higher level of edu- cation than non-completers) and parental support (com- pleters reported more support for their child than non- completers), as well as the child’s psychosocial strain (completers reported less psychosocial strain than non- completers), the child’s WRQoL (completers reported higher scores than non-completers), and family eating environment (completers reported higher scores than non-completers). p y g q BMI at baseline and weight loss during intervention are often reported to influence the drop-out in obesity interventions. With respect to the baseline BMI, we ob- served a higher drop-out rate in families whose children were heavier at baseline [4, 6]. In line with other reports [4, 5, 10], a lower initial weight loss increased the risk of not returning the follow-up assessments in our study. However, analyzing the variables in a multivariate model, only weight loss during intervention remained significant in terms of predicting drop-out at the 6-month follow- up, whereas at the 12-month follow-up, neither the baseline weight status nor the initial weight loss was relevant for individual attrition. Moreover, only at the short-term follow-up did drop-out rates differ between treatment groups, with parents in the intervention group seemingly more willing to return the follow-up data. This group took part in a weekend seminar, which stressed the important role of the parents in supporting their child. Since the two treatment groups did not differ in terms of BMI-SDS, this observation is not merely an effect of treatment effectiveness. Drop-out rates 6 and 12 months after the intervention The logistic regression to predict those families that missed the weight and height measurement explained 16 % of the variance after 6 months and 14 % after 12 months. It was also able to predict 60 % of the sam- ple correctly after 6 months and 67 % after 12 months. Results At the end of the intervention, the data of one child could not be obtained. Therefore, only the data from 522 children were available. Complete weight and height data were available for 259 (49.6 %) children at the 6- Warschburger and Kröller BMC Pediatrics (2016) 16:184 Page 4 of 9 Page 4 of 9 month follow-up and for 350 (67.0 %) at the 12-month follow-up. an expensive and time-consuming method (re-sending questionnaires and reminder postcards, repeated tele- phone calls, offering home visits and financial incen- tives). These strategies were considered as successful retention strategies to facilitate parents’ participation and receive the long-term data [30]. We assume that this strategy did at least pay off a little, since we invested the greatest efforts before the second follow-up and the at- trition rate at 12 months was slightly lower than that at the 6-month follow-up. Nevertheless, the attrition rate was high, and retention rates fell below our expectations. Further studies are needed to indicate empirically vali- dated retention strategies. In order to enhance study commitment and decrease attrition, the study by Ger- mann et al. [31] used an orientation session to give in- formation about achievable and healthy weight loss. We agree that this might be helpful in decreasing the num- ber of unsuccessful weight loss attempts, but it also ex- cludes many individuals with weight problems and focuses only on highly motivated patients. Further re- search is needed on how to increase the retention rate in clinical trials, especially when not only self-reports but also physiological measurements are required [28]. Differences between completers and non-completers At the 6-month follow-up, participation in the interven- tion group (odds ratio (OR)) = 0.60) and having older parents (OR = 0.95) was associated with a lower risk of dropping out, whereas a lower weight loss during the in- patient stay was associated with a higher risk (OR = 24.05). After 12 months, higher parental educational level (OR = 0.81) and a more structured family eating en- vironment (OR = 0.97) were associated with a lower risk of dropping out. Table 4 shows the results for the 12- month follow-up. Discussion Attrition is a highly relevant and prevalent problem in pediatric weight management trials. In the current study, we observed an attrition rate of 33.0 % at the 12-month follow-up. Our results are in line with those reported in the literature [3, 5, 7]. A recent review reported higher attrition rates in studies that focused on children with overweight or obesity (79.6 %) as well in long-term stud- ies (74 %) [28]. Based on the results of a previous study assessing parental factors which might impede or facili- tate their participation [29],8 we assumed time and fi- nancial constraints to be important. Therefore, we used Previous research results concerning the socio- demographic data were controversial. We observed no influence from the child’s age, which contradicts the re- sults of two other studies [4, 5]. Consistent with the lit- erature, no effects of gender were observed [4, 5, 7, 8]. In our study, parents’ age influenced the retention rate for the short-term follow-up, an effect that was no lon- ger visible 6 months later. Only at the 12-month follow- up was a higher level of parents’ education associated with a higher retention rate. Discussion We are aware of only one Warschburger and Kröller BMC Pediatrics (2016) 16:184 Page 5 of 9 Table 2 Comparison of completers and non-completers at 6-month follow-up Completers (n = 259) Non-Completers (n = 264) F (X2) p η2 Table 2 Comparison of completers and non-completers at 6-month follow-up Completers (n = 259) Non-Completers (n = 264) F (X2) p η2 Children Sex female 135 139 .02 .90 male 124 125 Age (years) 11.24 11.34 .85 .36 <.001 Initial BMI-SDS 2.52 2.60 5.63 .02 .01 Duration of inpatient stay (days) 39.67 39.69 <0.001 .98 <.001 Study arm IG 130 119 1.37 .24 CG 129 145 Weight change during stay (BMI-SDS) −0.35 −0.32 6.77 .01 .01 Health-related QoLa 67.94 66.28 2.48 .12 .01 Weight-related QoLa 46.40 44.08 2.24 .14 <.001 Self-efficacya 55.91 57.97 2.26 .13 .01 Psychosocial strain 6,41 6,35 <.001 .96 <.001 Food intake healthya 69.46 65.00 3.06 .08 .01 Problematica 48.69 47.28 .87 .35 <.001 Eating speeda 35.67 34.68 .29 .59 <.001 Structurea 72.46 69.66 4.19 .04 .01 Media consumptiona 12.06 11.74 .08 .78 <.001 Activity levela 1.06 1.05 .02 .90 <.001 Parents Age (years) 41.05 40.06 3.15 .08 .01 Educational level (years of school) 10.37 10.24 .95 .33 <.001 Family status in relationship 149 142 .14 .71 single 65 67 BMI (kg/m2; self-reported) 28.91 29.46 .68 .41 <.001 LQ mentala 48.71 47.71 1.18 .28 <.001 Physicala 50.05 49.65 .29 .59 <.001 Self-efficacya 64.99 63.77 .85 .36 <.001 Child’s supporta 73.07 71.66 2.28 .13 <.001 Note: F statistical test value, p significance value, η2 explained variance a mean scores on a scale ranging from 0 to 100 Note: F statistical test value, p significance value, η2 explained variance a mean scores on a scale ranging from 0 to 100 problems reported by the parents in the drop-out group. This concurs with the findings, with respect to prema- turely stopping the intervention [10, 13, 17]. However, the reported differences in psychological characteristics in this study were not independent predictors in the multivariate logistic regression. study in the field of pediatric weight management that reported similar results, even if only as tendencies [17]. With regard to psychological characteristics, the avail- able evidence is sparse. In line with our observation re- garding the differences between completers and non- completers, McCallum et al. [6] indicated that those who dropped out reported a lower quality of life for chil- dren. Discussion In addition, we found more psychological Further aspects that differ between the groups were the eating environment, in which a low degree of family Warschburger and Kröller BMC Pediatrics (2016) 16:184 Page 6 of 9 meal structure remained a significant predictor for attri- ti t 12 th ft i t ti Th i fl f 35]. Our results are further supported by the data of th t th t t t l i fl i t t t Table 3 Comparison of completers and non-completers at 12-month follow-up Completers (n = 350) Non-Completers (n = 173) F (X2) p η2 Children Sex female 177 97 1.40 .24 male 173 76 Age (years) 11.28 11.34 0.28 .60 <.001 BMI-SDS (measured) 2.52 2.63 8.53 <.001 .02 Duration of inpatient stay (days) 39.95 39.14 0.76 .39 <.001 Study arm IG 169 80 0.19 .66 CG 181 93 Weight change during stay (BMI-SDS units) −0.35 −0.32 5.04 .03 .01 Health-related QoLa 67.81 65.65 3.66 .06 .01 Weight-related QoLa 46.79 41.97 8.51 <.001 .02 Self-efficacya 57.01 56.79 0.02 .88 <.001 Psychosocial straina 12.89 14.42 5.85 .02 .01 Food intake healthya 68.23 65.16 1.25 .26 <.001 Problematica 47.76 48.52 0.22 .64 <.001 Eating speeda 35.52 34.45 0.29 .59 <.001 Structurea 72.42 68.18 8.34 <.001 .02 Media consumptiona 23.83 24.34 0.19 .66 <.001 Activity levela 1.12 0.93 3.38 .07 .01 Parents Age 40.62 40.42 0.11 .74 <.001 Educational level (years of school) 10.41 10.08 4.77 .03 .01 Family status relationship 206 85 2.63 .11 single 83 49 BMI (kg/m2; self-reported) 29.21 29.15 0.01 .94 <.001 QoL mentala 48.45 47.72 0.55 .46 <.001 Physicala 49.83 49.89 0.01 .95 <.001 Self-efficacya 64.32 64.54 0.02 .88 <.001 Child’s supporta 73.09 70.83 5.12 .02 .01 Note: F statistical test value, p significance value, η2 explained variance, QoL quality of life, IG intervention group, CG control group, BMI-SDS body mass index - standard deviation score a mean scores on a scale ranging from 0 to 100 Table 3 Comparison of completers and non-completers at 12-month follow-up Completers (n = 350) Non-Completers (n = 173) F (X2) p η2 35]. Our results are further supported by the data of other reports that stress parental influence in treatment adherence [10, 17]. meal structure remained a significant predictor for attri- tion at 12 months after intervention. Discussion The influence of the family eating environment may be interpreted as sign of a successful change in family habits – a major goal in pediatric weight loss interventions [32, 33]. In addition, studies from family-oriented intervention ap- proaches suggest that parents play a key role in sustain- ing the treatment effect at the long-term follow-up [34, Our study is limited in several ways. First, we could not assess any data at the follow-up measurements con- cerning the reasons for discontinuing the study. Some participants reported that when called by phone, they lost interest and that completing the questionnaires was Warschburger and Kröller BMC Pediatrics (2016) 16:184 Page 7 of 9 Table 4 Logistic regression to predict drop-out at 12-month follow-up Wald df p Exp(B) 95 % CI Children Sex 1.715 1 .190 1.386 .850–2.260 Age (years) 0.070 1 .791 1.025 .856–1.227 BMI-SDS (measured) 3.278 1 .070 1.870 .950–3.682 Study arm 1.038 1 .308 .785 .492–1.251 Weight change during stay 0.396 1 .529 1.886 .261–13.621 Weight-related QoL 0.260 1 .610 0.996 .982–1.011 Psychosocial strain 1.216 1 .270 1.023 .983–1.064 Eating structure 8.429 1 .004 .977 .962–0.992 Parents Educational level (years of school) 4.038 1 .044 .839 .707–0.996 Child’s support 0.117 1 .733 .996 .974–1.019 Note: Wald statistical test, df degrees of freedom, p significance level, Exp(B) odds ratio, 95 % CI confidence interval, QoL quality of life, BMI-SDS body mass index - standard deviation score Table 4 Logistic regression to predict drop-out at 12-month follow-up term (12 months after intervention) follow-ups. De Niet et al. [10] also found different predictors for at- trition at different stages of treatment. Whereas at the 6-month follow-up, mainly aspects associated with the intervention (randomization in the intervention group and initial weight loss) predicted the retention, at the 12- month follow-up, only family aspects such as educational level and family eating environment remained predictive. These differences indicate the risks inherent in only in- cluding a short-term follow-up, which might be biased in terms of success rates – especially when drop-out rates are high. Taking into account that in particular, short- term success in weight management does not necessarily imply positive long-term results, intervention studies should include longer follow-up periods and report their results on the basis of intention-to-treat analyses. too time-consuming. This is in line with the data reported by Savoye et al. [8]. and with our previous study [29]. Abbreviations 95 % CI C fid An important strength of our study is that we col- lected data from a highly diverse and representative sample of participants, rather than only including those families with a higher level of education or income. Moreover, the weight data were based on blind assess- ment, thus decreasing the risk of underreporting weight status (see self-reported measurements) [36]. 95 % CI: Confidence interval; BMI: Body mass index; BMI-SDS: Body mass index - standard deviation score; CG: Control group; df: Degrees of freedom; EPOC: Empowering parents of obese children; Exp(B): Odds ratio; F: Statistical test value; HRQoL: Health-related quality of life; IG: Intervention group; OR: Odds ratio; p: Significance value; QoL: Quality of life; RCT: Randomized controlled trial; SES: Socioeconomic status; Wald: Statistical test; WRQoL: Weight-related quality of life; η2: Explained variance Discussion In addition, our analyses were exploratory and we included many variables. We decided to take that path in order to not miss relevant features, and were willing to accept the increased risk of overestimating the clinical significance of the results. Furthermore, we also ran multivariate analyses in order to combat alpha error inflation. When interpret- ing our results in terms of comparing the pattern of short- and long-term follow-up data, it should be noted that we invested much more effort in gathering long-term data. Especially at the 12-month follow-up, we successfully con- tacted those parents who had simply forgotten to fill in the questionnaires due to time constraints or other prior- ities. Thus, we were able to observe differences otherwise obscured by organizational problems reported by the ma- jority of parents [8]. g We greatly appreciate the support of our cooperating clinics: • Kinder-Reha-Klinik “Am Nicolausholz” Bad Kösen • Charlottenhall Vorsorge und Rehabilitationsklinik für Kinder und Jugendliche Bad Salzungen • Fachklinik Prinzregent Luitpold Scheidegg • Edelsteinklinik Bruchweiler • Spessart-Klinik Bad Orb • Viktoriastift Bad Kreuznach • Kinder- und Jugendklinik Gesundheitspark Bad Gottleuba • Auguste-Viktoria-Klinik Bad Lippspringe • AHG Klinik für Kinder und Jugendliche Beelitz-Heilstätten Special thanks to Nadine Häusler for critical proofreading. Funding h d 12. Jelalian E, Hart CN, Mehlenbeck RS, Lloyd-Richardson EE, Kaplan JD, Flynn- O'Brien KT, Wing RR. Predictors of attrition and weight loss in an adolescent weight control program. Obesity. 2008;16:1318–23. g This study was funded by a DFG (German Research Foundation) grant (WA 1143/4-1; 4–2). The funding organization played no role in the design of the study and collection of the data, their analysis and interpretation and in writing the manuscript. 13. Zeller MH, Saelens BE, Roehrig H, Kirk S, Daniels SR. Psychological adjustment of obese youth presenting for weight management treatment. Obes Res. 2004;12:1576–86. 14. Dolinsky DH, Armstrong SC, Ostbye T. Predictors of attrition from a clinical pediatric obesity treatment program. Clin Pediatr. 2012;51:1168–74. 14. Dolinsky DH, Armstrong SC, Ostbye T. Predictors of attrition from a clinical pediatric obesity treatment program. Clin Pediatr. 2012;51:1168–74. Ethics approval and consent to participate pp p p Written informed consent to participate was obtained. The study approved by the Ethics Committee of the University of Potsdam on 19 May 2006. (no reference number) approved by the Ethics Committee of the University of Potsdam on 19 May 2006. (no reference number) 20. Ravens-Sieberer U, Bullinger M. KINDL-R. Fragebogen zur Erfassung der gesundheitsbezogenen Lebensqualität bei Kindern und Jugendlichen. Revidierte Form. Manual. 2000. Availability of data and materials Data will be deposited in a repository (doi: 10.5281/zenodo.164417 ). 15. Tershakovec AM, Kuppler K. Ethnicity, insurance type, and follow-up in a pediatric weight management program. Obesity. 2003;11:17–20. Consent to publish Consent to publish Consent to publish is part of the ethics approval. Consent to publish Consent to publish is part of the ethics approval. 19. Kromeyer-Hauschild K, Wabitsch M, Kunze K, Geller F, Hesse V, von Hippel A, Jaeger U, Johnsen D, Korte W, Müller G, Müller JM, Niemann-Pilatus A, Remer T, Wittchen H, Zabransky S, Zellner K, Ziegler A, Hebebrand J. Perzentile für den Body-mass-Index für das Kindes- und Jugendalter unter Heranziehung verschiedener deutscher Stichproben. Monatsschr Kinderheilkd. 2001;149:807–18. Consent to publish is part of the ethics approval. Conclusions We greatly appreciate the support of our cooperating clinics: • Kinder-Reha-Klinik “Am Nicolausholz” Bad Kösen • Charlottenhall Vorsorge und Rehabilitationsklinik für Kinder und Jugendliche Bad Salzungen • Fachklinik Prinzregent Luitpold Scheidegg • Edelsteinklinik Bruchweiler • Spessart-Klinik Bad Orb • Viktoriastift Bad Kreuznach • Kinder- und Jugendklinik Gesundheitspark Bad Gottleuba • Auguste-Viktoria-Klinik Bad Lippspringe • AHG Klinik für Kinder und Jugendliche Beelitz-Heilstätten Special thanks to Nadine Häusler for critical proofreading. Our study results suggest that the strategies to reduce the attrition rate, which we employed after the first follow-up, were successful, but still could not prevent a final attrition rate of over 33 % for the second follow-up. We were able to replicate differences between com- pleters and non-completers found in previous studies. However, we observed a different pattern of predic- tors between the short-term (6 months) and long- Our study results suggest that the strategies to reduce the attrition rate, which we employed after the first follow-up, were successful, but still could not prevent a final attrition rate of over 33 % for the second follow-up. • Fachklinik Prinzregent Luitpold Scheidegg Page 8 of 9 Page 8 of 9 Page 8 of 9 Warschburger and Kröller BMC Pediatrics (2016) 16:184 Page 8 of 9 Warschburger and Kröller BMC Pediatrics (2016) 16:184 Author details 1 f 21. Ravens-Sieberer U, Redegeld M, Bauer CP, Mayer H, Stachow R, Kiosz D, van Egmond-Fröhlich B, Rempis R, Kraft D, Bullinger M. Lebensqualität chronisch kranker Kinder und Jugendlicher in der Rehabilitation. Z Med Psychol. 2005;14:5–12. 1Department of Psychology, University of Potsdam, Counseling Psychology, Potsdam University, Karl- Liebknecht- Str. 24/25, 14476 Potsdam, Germany. 1Department of Psychology, University of Potsdam, Counseling Psychology, Potsdam University, Karl- Liebknecht- Str. 24/25, 14476 Potsdam, Germany. 1Department of Psychology, University of Potsdam, Counseling Psychology, Potsdam University, Karl- Liebknecht- Str. 24/25, 14476 Potsdam, Germany. 2Department of Health Psychology, H:G Hochschule für Gesundheit & Sport, Technik & Kunst, Vulkanstraße 1, 10367 Berlin, Germany. Department of Health Psychology, H:G Hochschule für Gesundheit & Sport, Technik & Kunst, Vulkanstraße 1, 10367 Berlin, Germany. 22. Warschburger P, Fromme C, Petermann F. Konzeption und Analyse eines gewichtsspezifischen Lebensqualitätsfragebogens für übergewichtige und adipöse Kinder und Jugendliche (GW-LQ-KJ). Z Klin Psychol Psychiatr Psychother. 2005;4:356–69. Technik & Kunst, Vulkanstraße 1, 10367 Berlin, Germany. Received: 2 April 2016 Accepted: 8 November 2016 p p 23. Warschburger P, Fromme C, Petermann F. Gewichtsbezogene Lebensqualität bei Schulkindern: Validität des GW-LQ-KJ. Z Gesundheitspsychol. 2004;12:159–66. Competing interests Competing interests The authors declare that they have no competing interests. 18. Warschburger P, Kröller K, Haerting J, Unverzagt S, Egmond-Frohlich A van: Empowering parents of obese children (EPOC): A randomized-controlled trial on additional long-term weight effects of a parent training. Appetite. 2016;103:148–56. Competing interests The authors declare that they have no competing interests. Authors’ contributions d h d f 16. Cote MP, Byczkowski T, Kotagal U, Kirk S, Zeller M, Daniels S. Service quality and attrition: an examination of a pediatric obesity program. Int J Qual Health Care. 2004;16:165–73. PW steered the design of the study, drafted the initial version of the manuscript, and approved the final manuscript as submitted. KK performed the statistical analysis, drafted the initial version of the manuscript, and approved the final manuscript as submitted. 17. Braet C, Jeannin R, Mels S, Moens E, van Winckel M. Ending prematurely a weight loss programme: the impact of child and family characteristics. Clin Psychol Psychother. 2010;17:406–17. References McCallum Z, Wake M, Gerner B, Baur LA, Gibbons K, Gold L, Gunn J, Harris C, Naughton G, Riess C, Sanci L, Sheehan J, Ukoumunne OC, Waters E. Outcome data from the LEAP (Live, Eat and Play) trial: a randomized controlled trial of a primary care intervention for childhood overweight/ mild obesity. Int J Obes. 2007;31:630–6. 6. McCallum Z, Wake M, Gerner B, Baur LA, Gibbons K, Gold L, Gunn J, Harris C, Naughton G, Riess C, Sanci L, Sheehan J, Ukoumunne OC, Waters E. Outcome data from the LEAP (Live, Eat and Play) trial: a randomized controlled trial of a primary care intervention for childhood overweight/ mild obesity. Int J Obes. 2007;31:630–6. 29. Warschburger P, Richter M. Gesunde Ernährung und Bewegung: Was verhindert und erleichtert Müttern den Zugang zu Präventionsprogrammen? Aktuel Ernahrungsmed. 2009;34:88–94. 7. Hughes AR, Stewart L, Chapple J, McColl JH, Donaldson MD, Kelnar CJ, Zabihollah M, Ahmed F, Reilly JJ. Randomized, controlled trial of a best-practice individualized behavioral program for treatment of childhood overweight: Scottish Childhood Overweight Treatment Trial (SCOTT). Pediatrics. 2008;121:e539. 30. Schoeppe S, Oliver M, Badland HM, Burke M, Duncan MJ. Recruitment and retention of children in behavioral health risk factor studies: REACH strategies. Int J Behav Med. 2014;21:794–803. 31. Germann JN, Kirschenbaum DS, Rich BH. Use of an orientation session may help decrease attrition in a pediatric weight management program for low-income minority adolescents. J Clin Psychol Med Settings. 2006; 13:169–79. 8. Savoye M, Nowicka P, Shaw M, Yu S, Dziura J, Chavent G, O'Malley G, Serrecchia JB, Tamborlane WV, Caprio S. Long-term results of an obesity program in an ethnically diverse pediatric population. Pediatrics. 2011;127:402–10. 32. Golan M, Crow S. Targeting parents exclusively in the treatment of childhood obesity: Long-term results. Obes Res. 2004;12:357–61. 9. Skelton JA, Beech BM. Attrition in paediatric weight management: A review of the literature and new directions. Obes Rev. 2011;12:e273–81. 33. Warschburger P. Psychologische Aspekte der Adipositas. Bundesgesundheitsbl. 2011;54:562–9. 10. de Niet J, Timman R, Jongejan M, Passchier J, van den Akker E. Predictors of participant dropout at various stages of a pediatric lifestyle program. Pediatrics. 2011;127:e164. 34. Germann JN, Kirschenbaum DS, Rich BH. Child and parental self-monitoring as determinants of success in the treatment of morbid obesity in low- income minority children. J Pediatr Psychol. 2007;32:111–21. 34. Germann JN, Kirschenbaum DS, Rich BH. References 1. Ahern K. Methodological issues in the effects of attrition: simple solutions for social scientists. Field Methods. 2005;17:53–69. 1. Ahern K. Methodological issues in the effects of attrition: simple solutions for social scientists. Field Methods. 2005;17:53–69. 1. Ahern K. Methodological issues in the effects of attrition: simple solutions for social scientists. Field Methods. 2005;17:53–69. 24. Kröller K, Warschburger P. Maternal feeding strategies and child’s food intake: Considering weight and demographic influences using structural equation modeling. Int J Behav Nutr Phys Act. 2009;6:78. 2. Karlson CW, Rapoff MA. Attrition in randomized controlled trials for pediatric chronic conditions. J Pediatr Psychol. 2009;34:782–93. 2. Karlson CW, Rapoff MA. Attrition in randomized controlled trials for pediatric chronic conditions. J Pediatr Psychol. 2009;34:782–93. 25. Lampert T, Sygusch R, Schlack R. Nutzung elektronischer Medien im Jugendalter. Bundesgesundheitsbl. 2007;50:643–52. 3. Collins CE, Warren J, Neve M, McCoy P, Stokes BJ. Measuring effectiveness of dietetic interventions in child obesity: A systematic review of randomized trials. Arch Pediatr Adolesc Med. 2006;160:906–22. 3. Collins CE, Warren J, Neve M, McCoy P, Stokes BJ. Measuring effectiveness of dietetic interventions in child obesity: A systematic review of randomized trials. Arch Pediatr Adolesc Med. 2006;160:906–22. 26. Woerner W, Becker A, Friedrich C, Rothenberger A, Klasen H, Goodman R. Normierung und Evaluation der deutschen Elternversion des Strengths and Difficulties Questionnaire (SDQ): Ergebnisse einer repräsentativen Felderhebung. Z Kinder Jugendpsychiatr Psychother. 2002;30:105–12. 4. Golley RK, Magarey AM, Baur LA, Steinbeck KS, Daniels LA. Twelve- month effectiveness of a parent-led, family-focused weight- management program for prepubertal children: A randomized, controlled trial. Pediatrics. 2007;119:517–25. 4. Golley RK, Magarey AM, Baur LA, Steinbeck KS, Daniels LA. Twelve- month effectiveness of a parent-led, family-focused weight- management program for prepubertal children: A randomized, controlled trial. Pediatrics. 2007;119:517–25. 27. Bullinger M, Kirchberger I. SF-36 Fragebogen zum Gesundheitsszustand - Manual. Göttingen: Hogrefe; 1998. 5. van den Akker EL, Puiman PJ, Groen M, Timman R, Jongejan MT, Trijsburg W. A cognitive behavioral therapy program for overweight children. J Pediatr. 2007;151:280–3. 5. van den Akker EL, Puiman PJ, Groen M, Timman R, Jongejan MT, Trijsburg W. A cognitive behavioral therapy program for overweight children. J Pediatr. 2007;151:280–3. 28. Cui Z, Seburg EM, Sherwood NE, Faith MS, Ward DS. Recruitment and retention in obesity prevention and treatment trials targeting minority or low-income children: a review of the clinical trials registration database. Trials. 2015;16:564. 6. Warschburger and Kröller BMC Pediatrics (2016) 16:184 35. Wrotniak BH, Epstein LH, Paluch RA, Roemmich JN. Parent weight change as a predictor of child weight change in family-based behavioral obesity treatment. Arch Pediatr Adolesc Med. 2004;158:342–7. 36. Gorber SC, Tremblay M, Moher D, Gorber B. A comparison of direct vs. self- report measures for assessing height, weight and body mass index: A systematic review. Obes Rev. 2007;8:307–26. 35. Wrotniak BH, Epstein LH, Paluch RA, Roemmich JN. Parent weight change as a predictor of child weight change in family-based behavioral obesity treatment. Arch Pediatr Adolesc Med. 2004;158:342–7. 36. Gorber SC, Tremblay M, Moher D, Gorber B. A comparison of direct vs. self- report measures for assessing height, weight and body mass index: A systematic review. Obes Rev. 2007;8:307–26. References Child and parental self-monitoring as determinants of success in the treatment of morbid obesity in low- income minority children. J Pediatr Psychol. 2007;32:111–21. 11. Skelton JA, Goff DC, Ip E, Beech BM. Attrition in a multidisciplinary pediatric weight management clinic. Child Obes. 2011;7:185–93. Page 9 of 9 Warschburger and Kröller BMC Pediatrics (2016) 16:184 • We accept pre-submission inquiries • Our selector tool helps you to find the most relevant journal • We provide round the clock customer support • Convenient online submission • Thorough peer review • Inclusion in PubMed and all major indexing services • Maximum visibility for your research Submit your manuscript at www.biomedcentral.com/submit Submit your next manuscript to BioMed Central and we will help you at every step: • We accept pre-submission inquiries • Our selector tool helps you to find the most relevant journal • We provide round the clock customer support • Convenient online submission • Thorough peer review • Inclusion in PubMed and all major indexing services • Maximum visibility for your research Submit your manuscript at www.biomedcentral.com/submit Submit your next manuscript to BioMed Central and we will help you at every step: • We accept pre-submission inquiries • Our selector tool helps you to find the most relevant journal • We provide round the clock customer support • Convenient online submission • Thorough peer review • Inclusion in PubMed and all major indexing services • Maximum visibility for your research Submit your manuscript at www.biomedcentral.com/submit Submit your next manuscript to BioMed Central and we will help you at every step: Submit your next manuscript to BioMed Central and we will help you at every step:
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172 Ausgaben mit 18.427 Seiten. Die Redaktion von Communicatio Socialis verabschiedet die dienstältesten Mitarbeiter
Communicatio socialis
2,012
cc-by
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In eigener Sache In eigener Sache Communicatio Socialis 45 (2012), Nr. 4: 335–340 Quelle: www.communicatio-socialis.de Communicatio Socialis 45 (2012), Nr. 4: 335–340 Quelle: www.communicatio-socialis.de 1 1988 erschien Communicatio Socialis nicht (nur ein Register), 1989 nur ein Heft; auch kamen einzelne Ausgaben als Doppelnummern heraus. Nicht bei dieser Sta- tistik eingerechnet sind die zwölf Beihefte, die zwischen 1972 und 2010 zumeist in Buchform erschienen. Bei fünf dieser Sonderausgaben wirkte Schmolke als alleiniger Herausgeber oder Mitherausgeber (1972 zu „Communio et Progressio“, 1974 zu „Publik“, 1977 zur katholischen Publizistik in den Niederlanden, 1992 zur Situation der Kirchenpresse in Europa und den USA sowie 2010 als Fest- schrift für Walter Hömberg). 172 Ausgaben mit 18 427 Seiten Die Redaktion von Communicatio Socialis verabschiedet die dienstältesten Mitarbeiter Diese Ausgabe bildet eine Zäsur in der 45-jährigen Geschichte von Com- municatio Socialis. Die Redaktion hat bei ihrer letzten Zusammenkunft mit großer Wehmut ihre drei dienstältesten Mitarbeiter verabschiedet. Nicht ohne Grund fand dieses Treffen, bei dem wie immer die jüngsten Hefte lobend und kritisierend besprochen und die nächsten Ausgaben geplant wurden, in Salzburg statt. Seit dem 6. Jahrgang, Heft 4, fin- det sich eine Salzburger Anschrift im Impressum von Communicatio Socialis. Der Name, der bei dieser Adresse steht, lautet Michael Schmolke. Er war jugendliche 33 Jahre alt, frisch promoviert mit einer Arbeit über „Kolping als Publizist“ und Assistent am Institut für Publizistik in Münster, als ihn Franz-Josef Eilers von den Steyler Missionaren dafür gewinnen konnte, mit ihm gemeinsam diese „Zeit- schrift für Publizistik in Kirche und Welt“ (so lautete der Untertitel bis 1992) zu gründen. Nach Vorarbeiten im Jahr 1967 erschien die erste Ausgabe Anfang 1968. Unter der Überschrift „Publizistik als Aufgabe“ hieß es in der programmatischen Einleitung: „Die neue Zeitschrift soll solchen Erkenntnissen und Erfahrungen aus dem Ge- samtbereich der Publizistik ihre Seiten öffnen, die mittelbar oder unmittelbar für kirchliche publizistische Arbeit bedeutsam sein können. Sie soll durch Beiträge von Fachleuten auf Probleme und Aufgaben hinweisen und zu ihrer Lösung bei- tragen – durch Information, Anregung und Kritik. […] Diese Zeitschrift, die der Bereitschaft verschiedener privater Stellen und dem Mut des Verlages ihr Ent- stehen verdankt, möchte ihren Teil zu der Erfüllung der publizistischen Aufgabe der Kirche beitragen. Sie ist nach dem zweiten Weltkrieg die erste katholische Fachzeitschrift dieser Art – nichtsdestoweniger ist sie auf das Wohlwollen und die Mitarbeit aller angewiesen, die sich ihren Zielen verpflichtet fühlen.“ Wohl niemand fühlte sich dem publizistischen Projekt mehr verpflich- tet als Michael Schmolke. Das Amt des Herausgebers war für ihn zwar auch ein Ehrenamt, aber nicht bloß schmückender Ehrentitel. Er ver- stand darunter wahrhaftig „Publizistik als Aufgabe“, verbunden mit manchen Mühen. Das Amt des Herausgebers nahm Michael Schmolke mit, als er 1973 Ordinarius für Publizistik und Kommunikationswis- senschaft an der Universität Salzburg wurde, und er füllte es mit glei- chem Herzblut aus, nachdem er 2002 emeritiert wurde. Nun, mit fast 79 Jahren, verabschiedet sich der Gründer aus dem aktiven Dienst. 335 https://doi.org/10.5771/0010-3497-2012-4-335, am 24.10.2024, 06:46:36 Open Access – - https://www.nomos-elibrary.de/agb In eigener Sache In eigener Sache Vor kurzem hat Michael Schmolke dem Verfasser dieser Zeilen ei- nen Satz aller jemals erschienen Communicatio-Hefte zur Archivierung übergeben, den er doppelt besaß. In Ermangelung eines passenden Regalfaches mussten die Zeitschriften auf dem Klavier zwischenge- lagert werden. Sie reichen, nebeneinander aufgestellt, vom tiefsten A bis zum höchsten C, einmal entlang der kompletten Klaviatur und so- gar noch etwas darüber hinaus – insgesamt 132 Zentimeter. Mit dieser Ausgabe sind es 172  Hefte mit 18 427 Seiten1, an deren Konzeption Michael Schmolke beteiligt war und die er – wie wir aus der Zusam- menarbeit der vergangenen Jahre wissen – vor der Drucklegung stets akribisch auf inhaltliche und satztechnische Fehler gelesen hat. Vor allem aber war Michael Schmolke selbst der fleißigste Autor. Seit der ersten Ausgabe trugen 194 Beiträge in dieser Zeitschrift seinen Namen oder das Kürzel „M.S.“. Damit füllte er zusammenge- rechnet 481 Seiten – also gut und gerne noch einmal so viel Stoff wie seine 1971 als Buch erschienene Habilitation über „Die schlech- te Presse – das Verhältnis der deutschen Katholiken zur Publizistik zwischen ‚Katholik‘ (1821) und ‚Publik‘ (1968)“, die der Rezensent Konrad Simons in dieser Zeitschrift eine „verdienstvolle und ins Mark kirchlicher Publikationsscheu vorstoßende Darstellung“ nannte (Heft 4/1972). Die Besprechung endet mit dem Satz: „Die Fortsetzung zu Michael Schmolkes Untersuchung […] könnte ein neuer Schmolke werden etwa mit dem Arbeitstitel: der unbegrenzte Spielraum ka- tholischer Publizistik an der Schwelle des Jahres 2000.“ Dass dieser Band nie erschienen ist, lag wohl weniger am Autor. g g Die Geschichte und aktuelle medienpolitische Fragestellungen der katholischen Publizistik sowie die immer wieder untersuchte Lage der Kirchenzeitungen (so z. B. „Die Bistumspresse von Analyse zu Analyse“; Heft 3/1996) bilden den Schwerpunkt von Michael Schmol- kes Veröffentlichungen in Communicatio Socialis. Daneben findet sich Grundsätzliches zu seinem Lehrgebiet, etwa schon im ersten Jahrgang ein Essay über die neue Ausrichtung der Publizistikwissenschaft und ihre Bezüge zur alten, normativen Zeitungswissenschaft („Fragen zum Ort von Gesinnungskräften im publizistischen Funktionieren“, 336 https://doi.org/10.5771/0010-3497-2012-4-335, am 24.10.2024, 06:46:36 Open Access – - https://www.nomos-elibrary.de/agb 336 p 172 Ausgaben mit 18 427 Seiten Mitherausgeber von Communicatio Socialis seit der ersten Ausgabe 1968: Michael Schmolke (Foto: Christian Klenk) Mitherausgeber von Communicatio Socialis seit der ersten Ausgabe 1968: Michael Schmolke (Foto: Christian Klenk) Heft 2/1968). Außerdem war Michael Schmolke von Beginn an eifri- ger Rezensent. Für die Vorstellung von Neuerscheinungen in „seiner“ Zeitschrift las er ein ganzes Bücherregal. In eigener Sache 129 Buchbesprechungen sind mit seinem Namen gekennzeichnet (teilweise sind es Sammelre- zensionen mehrerer Bände). Schließlich belieferte er die Redaktion regelmäßig mit Beiträgen für die Rubrik „Zur Person“. Viele Freunde und Kollegen hat Michael Schmolke damit auf dem Weg in den Ruhe- stand und auch in letztem ehrenden Andenken gewürdigt. Heft 2/1968). Außerdem war Michael Schmolke von Beginn an eifri- ger Rezensent. Für die Vorstellung von Neuerscheinungen in „seiner“ Zeitschrift las er ein ganzes Bücherregal. 129 Buchbesprechungen sind mit seinem Namen gekennzeichnet (teilweise sind es Sammelre- zensionen mehrerer Bände). Schließlich belieferte er die Redaktion regelmäßig mit Beiträgen für die Rubrik „Zur Person“. Viele Freunde und Kollegen hat Michael Schmolke damit auf dem Weg in den Ruhe- stand und auch in letztem ehrenden Andenken gewürdigt. In seinem letzten Beitrag als Herausgeber (hoffentlich nicht der letzte überhaupt!) erinnert Michael Schmolke in diesem Heft noch ein- mal an all jene Menschen, die in den vergangenen Jahrzehnten mit ihm an dieser Zeitschrift gearbeitet haben. Zwei von ihnen verabschieden sich zusammen mit dem Gründungsherausgeber aus der aktiven Re- daktionsarbeit. Ute Stenert engagierte sich für diese Zeitschrift als Mitheraus­geberin neben ihrer zeit­intensiven Tätigkeit als Referats- leiterin Presse und Verlagswesen im Sekretariat der Deutschen Bi- schofskonferenz in Bonn. Seit rund einem Jahr ist sie für das Referat Rundfunk und Medienethik verantwortlich. Ute Stenert studierte Pub- lizistik, Politikwissenschaft und Soziologie in Mainz und Münster, war 337 In eigener Sache Ferdinand Oertel (Autor seit 1969, Redakteur seit 2003) und Ute Stenert (Mitherausgeberin seit 2005) (Fotos: Christian Klenk) Ferdinand Oertel (Autor seit 1969, Redakteur seit 2003) und Ute Stenert (Mitherausgeberin seit 2005) (Fotos: Christian Klenk) nach ihrem Examen PR-Redakteurin und anschließend wissenschaft- liche Mitarbeiterin am Mainzer Institut für Publizistik. Eine Kurzfas- sung ihrer Dissertation über die Entstehung des Südwestrundfunks erschien in Communicatio Socialis (Heft 3/2004) – und nur zwei Aus- gaben später war sie Mitherausgeberin. Dank ihrer guten Kontakte im Bereich der katholischen Publizistik konnte sie der Redaktion in den vergangenen acht Jahren häufig neue Themen und Autoren vermitteln, regelmäßig hat sie selbst geschrieben und Interviews geführt. g g g g Der Name Ferdinand Oertel taucht in dieser Zeitschrift das ers- te Mal 1969 auf. In Heft 4 schrieb der damalige Chefredakteur der katholischen Wochenzeitung „Die christliche Familie“ über „Die Zu- kunft der katholischen Sonntagspresse im Licht einer Leser-Umfrage“. Die kirchliche Presse war und ist bis heute das Lebensthema von Ferdi Oertel, wie er seine Mails und Briefe unterzeichnet. In eigener Sache Folgerichtig trägt seine 2009 erschienene Biografie den Titel „Der Kirchenzeitungsmann“ (die zweite Auflage erschien 2012). Oertels Lebensstationen färbten allesamt auf sein publizistisches Wirken ab. Neben dem Anglistik-, Germanistik- und Kunstgeschichte-Studium im heimatlichen Köln war er für zwei Semester als Austauschstudent in St. Louis in den USA, wo er auch Journalistik studierte. Bis heute beobachtet er wie kein anderer in Deutschland die Entwicklung der katholischen Publizistik in den Vereinigten Staaten und verfasst dazu regelmäßig Lageberichte in Communicatio Socialis und in der „Herder Korrespondenz“. 338 https://doi.org/10.5771/0010-3497-2012-4-335, am 24.10.2024, 06:46:36 Open Access – - https://www.nomos-elibrary.de/agb 338 172 Ausgaben mit 18 427 Seiten 172 Ausgaben mit 18 427 Seiten 172 Ausgaben mit 18 427 Seiten Nach der Promotion und einem Volontariat bei der Kölner Kirchen­ zeitung begann seine berufliche Karriere: 1956 Leiter der Pressestelle des Kölner Katholikentages, 1957 bis 1960 Kulturredakteur und Chef vom Dienst bei der Katholischen Nachrichtenagentur, 1961 bis 1973 Chefredakteur der Wochenzeitung „Die christliche Familie“, 1973 bis 1980 Chefredakteur der „Aachener Kirchenzeitung“, von 1980 an schließlich Chefredakteur der Zeitschrift „Leben  & Erziehen“. Daneben engagierte er sich in verschiedenen Gremien: als Vorsitzen- der der Arbeitsgemeinschaft Katholische Presse, als Berater publi- zistischer Kommissionen der Deutschen Bischofskonferenz und beim Zentralkommitee der deutschen Katholiken, als Mitbegründer und Präsident der Internationalen Föderation der katholischen Presse im Dachverband Katholische Weltunion der Presse. Als Ferdinand Oertel 1992 in den Unruhestand eintrat, würdigte Michael Schmolke seine Lebensleistungen auch in Communicatio Socialis (Heft 1/1993): „Wer die Stationen seines Lebenslaufes bedenkt, sieht, daß er immer Täter war, aber für viele Jahre zugleich Beobachter. Beobachter, Kritiker und Ana- lysator […]. Ein Berater, der auf der Grundlage des Nachdenkens über den eigenen Beruf Rat gegeben hat, der aber reflektierend in der Lage war, sein Metier und seine Branche in Frage zu stellen. Unter den Redakteuren der Kir- chenpresse war er kein Enfant terrible, gehörte wohl gerade noch zum Main- stream, machte aber gelegentlich Vorschläge, die von der Mehrheit nicht als verwirklichenswert eingestuft wurden.“ Ferdinand Oertel hat in allen Positionen und Ämtern eine Öffnung der Kirchenpresse zur Welt und zu einem professionellen Journalis- mus propagiert. Seine Beobachtungen und Kommentierungen setzte er auch nach der Pensionierung fort – als „Redakteur i. N. (im Ne- benberuf)“ (Oertel über Oertel). Mit 75 Jahren war er wieder Chefre- dakteur. Von Heft 1/2003 an stand sein Name zusammen mit dieser Funktionsbezeichnung im Impressum von Communicatio Socialis. In eigener Sache Fünf Jahrgänge der Zeitschrift redigierte er alleine, danach konzen­trierte er sich vor allem auf die Rubrik „Notabene“, schrieb aber weiterhin auch noch Berichte, Kommentare und Rezensionen. Insgesamt 51 Beiträge hat Ferdinand Oertel für diese Zeitschrift verfasst (die Ru- brik „Notabene“ nicht eingerechnet). Am 24. Oktober 2012 hat Fer- dinand Oertel gemeinsam mit seiner Frau während einer Italienreise seinen 85. Geburtstag gefeiert. Den Generationenwechsel bei Com- municatio Socialis nimmt er nun zum Anlass, sich ganz jener Tätig- keit zuzuwenden, die am Anfang seines Werdegangs stand: als „freier Schriftsteller“ literarische Prosa zu scheiben, „denn im Innern fühlte ich mich zum Dichten berufen“, schreibt er in seiner Biografie. 339 In eigener Sache Den allerersten Aufsatz in dieser Zeitschrift verfasste der Wiener Kardinal Franz König. Sein Beitrag mit dem Titel „Kirche und Kom- munikation“ (Heft 1/1968) endet so: Den allerersten Aufsatz in dieser Zeitschrift verfasste der Wiener Kardinal Franz König. Sein Beitrag mit dem Titel „Kirche und Kom- munikation“ (Heft 1/1968) endet so: „Die moderne Gesellschaft befindet sich in einem raschen Wandel; die Ver- lautbarung religiöser Inhalte muß also mit einer Umgebung rechnen, die sich in unausgesetzter Veränderung befindet. Religiöse Inhalte in der Massenkom- munikation werden immer schärfer von Inhalten konkurrenziert, die sehr ein- fachen menschlichen Bedürfnissen – z. B. der Schaulust – entgegenkommen und erstaunlicherweise nicht selten archaisch-mythische Inhalte in moderner Verpackung anbieten; man hat in diesem Zusammenhang von der modernen Massenkultur gesprochen. Ein sehr entscheidender Faktor dürfte auch die weitverbreitete Verbraucher- oder Konsumentenmentalität sein, die einer mehr kontemplativen Lebensweise direkt entgegengesetzt ist. Schließlich darf auch noch auf jenes Phänomen hingewiesen werden, das heute unter dem Namen der „Säkularisation“ immer mehr Beachtung findet und für zukünftige Strate- gien religiöser Kommunikation in Rechnung gestellt werden muß.“ Königs Ausführungen sind auch 45 Jahre nach ihrer Formulierung als Aufgabenstellung für diese Zeitschrift zu verstehen – mit dem Un- terschied, dass die beschriebenen Herausforderungen seither um ein Vielfaches mächtiger geworden sind. Die Strategien religiöser Kom- munikation wird Communicatio Socialis weiterhin analysieren und kommentieren. Medienethische Fragestellungen, denen sich auch die katholischen Bischöfe in letzter Zeit unter anderem mit einem Impuls­ papier zu „Virtualität und Inszenierung“ in der digitalen Welt gewid- met haben (vgl. Heft 4/2011), werden darüber hinaus künftig in dieser Zeitschrift einen größeren Raum einnehmen. Das neue Heftkonzept haben die scheidenden Herausgeber und die neue Generation in den vergangenen Monaten gemeinsam entwickelt – es soll im Laufe des Jahres 2013 umgesetzt und dann auch näher erläutert werden. In eigener Sache Für die neue Blattlinie stehen künftig diese drei Herausgeber: Klaus-Dieter Altmeppen (Inhaber des Lehrstuhls für Journalistik  II an der Katholischen Universität Eichstätt-Ingolstadt), Andreas Büsch (Professor für Medienpädagogik und Kommunikationswissen- schaft an der Katholischen Hochschule Mainz und Leiter der von der Bischofskonferenz eingerichteten Clearingstelle Medienkompetenz) sowie Alexander Filipovic´ (Akademischer Rat am Institut für Christ- liche Sozialwissenschaften an der Westfälischen Wilhelms-Universi- tät Münster). Die Eichstätter Redaktion von Communicatio Socialis, Annika Franzetti, Renate Hackel-de Latour und Christian Klenk, freut sich auf die Zusammenarbeit. Im Namen der Redaktion Ch i ti Kl k 340 https://doi.org/10.5771/0010-3497-2012-4-335, am 24.10.2024, 06:46:36 Open Access – - https://www.nomos-elibrary.de/agb 340 p
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Energy and economic analysis of environmental upgrading of existing office buildings
Construction economics and building
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Citation: Ding, G., Nguyen, D. M., and Runeson, G. 2020. Energy and economic analysis of environmental upgrading of existing office buildings. Construction Economics and Building, 20:4, 82-102. http:// dx.doi.org/10.5130/AJCEB. v20i4.7239 ISSN 2204-9029 | Published by UTS ePRESS | https://epress. lib.uts.edu.au/journals/index. php/AJCEB Construction Economics and Building Vol. 20, No. 4 December 2020 RESEARCH ARTICLE DECLARATION OF CONFLICTING INTEREST The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. FUNDING The author(s) received no financial support for the research, authorship, and/or publication of this article. DOI: 10.5130/AJCEB.v20i4.7239 Article history: Received 01/06/2020; Revised 15/09/2020; Accepted 02/10/2020; Published 07/12/2020 DOI: 10.5130/AJCEB.v20i4.7239 Article history: Received 01/06/2020; Revised 15/09/2020; Accepted 02/10/2020; Published 07/12/2020 DOI: 10.5130/AJCEB.v20i4.7239 © 2020 by the author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) License (https:// creativecommons.org/licenses/ by/4.0/), allowing third parties to copy and redistribute the material in any medium or format and to remix, transform, and build upon the material for any purpose, even commercially, provided the original work is properly cited and states its license. Energy and economic analysis of environmental upgrading of existing office buildings Vol. 20, No. 4 December 2020 Vol. 20, No. 4 December 2020 Dinh Manh Nguyen, Grace Ding* and Göran Runeson Dinh Manh Nguyen, Grace Ding* and Göran Runeson School of Built Environment, Faculty of Design, Architecture and Building, University of Technology Sydney Dinh Manh Nguyen, Grace Ding* and Göran Runeson School of Built Environment, Faculty of Design, Architecture and Building, University of Technology Sydney School of Built Environment, Faculty of Design, Architecture and Building, University of Technology Sydney *Corresponding author: Grace Ding, School of Built Environment, Faculty of Design, Architecture and Building, University of Technology Sydney. Email - grace.ding@uts.edu.au Introduction Over the years, the building sector has been recognised as one of the main sectors to negatively impact on the environment, creating shortages of natural resources, ozone depletion, emissions of carbon dioxide (CO2), climate changes, and the deterioration of living and working environments. This means that the building sector must improve to meet sustainability requirements. The major challenge in the building sector today, therefore, is to construct and maintain buildings in a more sustainable manner (Chan, Wang and Raffoni, 2014). Climate change, as debated for several decades, has captured people’s attention because of the increase in the earth’s average temperature (IPCC, 2014). The building sector is one of the sectors contributing to accelerated climate change. However, in return, climate change also impacts on buildings with extreme weather conditions occurring more frequently, hampering indoor comfort, and impacting productivity (Clarke, 2009; Cleugh et al., 2011). Increased temperatures make many advanced technologies applied in buildings ineffective, which then require more energy to maintain indoor comfort (Ürge-Vorsatz et al., 2007; Hinnells et al., 2008). The situation is particularly severe in office buildings as people spend most of the time indoor during working hours. The operating phase is the most extended period over a building’s lifecycle. In this period, buildings consume most of the energy and consequently emit the highest amount of greenhouse gases (GHG) into the environment (Huovila et al., 2009; Ibn-Mohammed et al., 2013). The primary substance that contributes to climate change is CO2 (Lynas, 2007; Li and Yao, 2009). Existing buildings are one of the major sources responsible for emitting high levels of CO2 into the environment in the process of material manufacture and consumption for maintenance in addition to the operating phase of a building (Wilson and Tagaza, 2006; Ürge- Vorsatz, Koeppel and Mirasgedis, 2007; Ürge-Vorsatz et al., 2007; Kohler and Yang, 2007; Wright, 2009; Zhou et al., 2016). Even though new buildings are increasingly constructed more sustainably, the number of new buildings added each year is small compared to the many largely old and outdated buildings in the stock (Wilkinson and Reed, 2006; Zhou et al., 2016). Since the general conditions of the existing building stock is deteriorating, the adverse impacts on the environment will continue unless the buildings’ performance is improved (Wilkinson and Reed, 2006). Keywords: Energy upgrading, existing office buildings, energy efficiency, upgrading activities, economic analysis. Abstract Over many decades, buildings have been recognised as a significant area contributing to the negative impacts on the environment over their lifecycle, accelerating climate change. In return, climate change also impacts on buildings with extreme heatwaves occurring more frequently and raising the earth’s temperature. The operation phase is the most extended period over a building’s lifespan. In this period, office buildings consume most energy and emit the highest amount of greenhouse gas pollution into the environment. Building upgrading to improve energy efficiency seems to be the best way to cut pollution as the existing building stock is massive. The paper presents an economic analysis of energy efficiency upgrade of buildings with a focus of office buildings. The paper identifies upgrading activities that are commonly undertaken to upgrade energy efficiency of office buildings and a case study of three office buildings in Sydney, Australia has been used to analyse the results. The upgrading activities can improve the energy performance of the case study buildings from 3 stars to 5 stars NABERS energy rating in compliance with the mandatory requirement in the Australian government’s energy policy. With the potential increase in energy price, energy efficiency upgrading will become more affordable, but currently, most of them, except solar panels and motion sensors show a negative return and would not be undertaken if they did not also contribute to higher rental income and an increased life span of the building. The upgrading 82 Energy and economic analysis of environmental upgrading of existing office buildings discussed in the paper represent a potentially attractive alternative to demolition and building anew. discussed in the paper represent a potentially attractive alternative to demolition and building anew. Introduction Hence, the approach to alleviating the environmental impact of existing buildings is to either demolish and rebuild or retain and upgrade the existing building stock. The primary target in reducing the impact of buildings in the environment is to reduce CO2 emissions (Lynas, 2007; Li and Yao, 2009; Burroughs, 2018). Research has shown that sustainable upgrading of the existing building stock can achieve this and so improve the value of buildings (Newell, MacFarlane and Walker, 2014; Wilkinson, 2014). However, 83 Construction Economics and Building, Vol. 20, No. 4, December 2020 Ding, Nguyen and Runeson many barriers limit stakeholders’ willingness to make their buildings more environmentally friendly. The main obstacles include budgetary constraint, insufficient information, various uncertainties as well as the lack of knowledge of and confidence in new technologies for upgrading (Wilson and Tagaza, 2006; Elmualim et al., 2010; Bruce et al., 2015; Regnier et al., 2018). The research aims at identifying upgrading activities commonly undertaken to improve energy efficiency to the base building of existing office buildings. The research design includes a comprehensive literature review to characterise upgrading activities and the associated potential savings on energy consumption. There are several research objectives, including identifying activities and technologies that cause minimal disturbance to the existing operation of buildings. Therefore, activities that require major renovation, such as building envelope, are excluded from the study. Secondly, analyse potential saving in energy consumption, CO2 emissions and the associated upgrading costs and saving of these activities and technologies. The final objective is to validate the analysis of these upgrading activities through a case study of three buildings. The paper began with a discussion of the impact of existing office buildings on the environment, followed by a discussion of upgrading activities that are commonly conducted to improve energy efficiency of existing office buildings. The discussion focuses on analysing upgrading cost and the potential savings in energy cost, energy consumption and CO2 emissions after upgrading. Finally, the paper presents a case study of three office buildings in Sydney, Australia to analyse the upgrading improvement, potential savings and compliance with the energy requirements for buildings in Australia. Environmental impact of existing office buildings and the role of energy upgrading Recently, the rapidly increasing average temperature on earth has influenced the living environment significantly. As a direct result of climate change, and in particular, the continual and extreme heatwaves, people are responding by increasing the use of indoor climate modifiers such as Heating, Ventilation and Air Conditioning (HVAC) systems to maintain indoor comfort, which has escalated the demand for energy and hence CO2 emissions (Kentwell, 2007; Anderson, Hawkins and Jones, 2016). The operating phase is the most extended and complicated period in a building’s lifecycle. The most significant emissions happen in the operating phase, approximately 80-90% of CO2 emissions, which is typically about 20-60 years, compared to the construction phase of usually 2-3 years (Huovila et al., 2009). The cost of operation and maintenance of office buildings can be as high as two times more than the cost of the initial construction for a period of 30 years and it can increase up to five times more for a longer lifespan (Ive, 2006; Snodgrass, 2008). The most significant expenses are for indoor comfort, lighting, and the operation of equipment. Office buildings are among the highest consumers of energy, and consequently, contribute high levels of GHG emissions (Ibn-Mohammed et al., 2013). The annual energy consumption of office buildings varies between 100 and 1,000 kWh per square metre depending on many variables, such as geographic location, type and use of office equipment, operational schedules, type of envelope, use of HVAC and lighting systems (Juan, Gao and Wang, 2010). In order to keep an office building functioning, it generally requires a major refurbishment every 20–25 years (Wilkinson and Reed, 2006; Bruce et al., 2015). Furthermore, most of the Construction Economics and Building, Vol. 20, No. 4, December 2020 84 Energy and economic analysis of environmental upgrading of existing office buildings existing office buildings are several decades old and therefore are becoming energy inefficient and may require upgrading to alleviate their impact in the environment (Wilkinson and Reed, 2006; Taylor, 2009). A deteriorating building decreases in value and the quality of the indoor environment will also deteriorate to the extent that it may harm the occupants, threaten production and cost more to operate (Pitt, Goyal and Sapri, 2006; Huovila et al., 2009). Therefore, old buildings need refurbishment to meet green standards and regulations and improve energy performance (Bullen, 2007; Connelly and Adam, 2009). Environmental impact of existing office buildings and the role of energy upgrading Improving the energy efficiency of existing buildings attracts much attention as an important strategy to reduce energy consumption and CO2 emissions (Huovila et al., 2009; Ibn-Mohammed et al., 2013). Energy efficiency upgrading of existing office buildings is a key target for public policy addressing climate change (Kentwell, 2007; Wild, 2008; Burroughs, 2018; Regnier et al., 2018). However, budget constraint is a major barrier to restrict building upgrading activities. Additional costs, increased risks, and unknown performance of technologies to meet green building standards may lead stakeholders to become reluctant to considering upgrading their buildings (Regnier et al., 2018). However, even though there are barriers that may prevent owners from upgrading an existing building, there are many drivers that may lead stakeholders to consider upgrading their buildings. The financial return is one of the major drivers as sustainable upgrading has the potential to improve an existing building to satisfy the economic needs of long-term wealth and the requirements of environmental protection (Pitt et al., 2009; Häkkinen and Belloni, 2011). Tenant demand is another significant driver for energy efficiency upgrading as these buildings will benefit from the green branding, meet standards for the building leases and occupations, and provide an indoor environment quality that improves user’s health and productivity (Henderson, 2006; Wilson and Tagaza, 2006; Clarke, 2009; Cleugh et al., 2011; Burroughs, 2018). The building sector is moving towards becoming greener with more injections of green buildings, and when a building is deemed outdated, building owners could consider upgrading the building, so that it can re-entering the building market (Chan, Qian and Lam, 2009). IMPROVING ENERGY EFFICIENCY IN EXISTING OFFICE BUILDINGS The rapid growth of the property industry has accelerated change in the environment, including technologies, standards, policies, and regulations. Existing office buildings, particularly older ones, may not have kept up with the changes. However, under the current environmental protection policies and regulations, older buildings are required to satisfy environmental protection standards. For the existing building stock, the target is to improve buildings to be more environmentally friendly (Abdallah and El-Rayes, 2015). The primary demand for improving buildings for sustainability is to ensure energy consumption and CO2 emissions reductions in buildings (Henderson, 2006; Wright, 2009). This can be achieved by upgrading buildings to improve their energy efficiency, indoor comfort for occupants, lighting and air conditioning 85 Construction Economics and Building, Vol. 20, No. 4, December 2020 85 Ding, Nguyen and Runeson systems, and waste reusing and recycling (Jentsch, James and Bahaj, 2010; Abdallah and El- Rayes, 2015). While almost every new office building is now constructed encompassing green technologies and innovative design, existing office buildings can also be improved or upgraded to meet sustainability standards (Abdallah and El-Rayes, 2015). The most significant advantage that existing office buildings gain by being sustainable is that they will stay competitive, increase energy efficiency, reduce vacancy rates, increase rental levels, improve assets and counteract obsolescence (Wilkinson and Reed, 2006; Chan, Qian and Lam, 2009). Sustainable buildings increase in value, gain positive influence in keeping tenants, who will be provided with considerable savings on energy and water in running their businesses. The challenge is improving the performance of existing buildings to lessen their negative environmental impact. The challenge is not only to limit CO2 emissions but to reduce CO2 emissions with a target level that is high but achievable. Reducing energy consumption will result in reduced CO2 emissions. As reported by the Fourth Assessment Report of the IPCC (2007), the commercial sectors can save approximately 1.4 billion tonnes (approximately 29%) of CO2 by 2020 when buildings are improved for energy efficiency. These GHG emissions can be reduced by approximately 29% or even to zero-net with a further commitment (Ürge- Vorsatz, Koeppel and Mirasgedis, 2007). During the operating stage of a building, energy consumption to provide heating, cooling, lighting and to operate equipment and appliances is recognised as the most important (Juan, Gao and Wang, 2010; Lecamwasam, Wilson and Chokolich, 2012; Abdallah and El-Rayes, 2015; Regnier et al., 2018). IMPROVING ENERGY EFFICIENCY IN EXISTING OFFICE BUILDINGS In the US, the building sector is responsible for approximately 39% of the total primary energy requirements, of which 35% was used for HVAC as about 80% of buildings in the US are equipped with air-conditioning systems (Nicol, 2009; Wan et al., 2012). In Canada, building space heating and cooling account for 54% and 6% of energy use respectively; while equipment, lighting, and hot water systems account for 20%, 13% and 7% respectively (Ürge-Vorsatz et al., 2007). In China, energy use in the building stock has been steadily increased since the 1980s. Buildings consumed around 24% of the total national energy use in 1996, rose to around 28% in 2001 and the growth was projected to rise to about 35% in 2020 (Wan et al., 2012). In Australia, office buildings account for 25% of the total energy which is projected to increase to 29% in 2020 (Department of Climate Change and Energy Efficiency, 2012; Higgins et al., 2014). The CO2 emissions will increase from 23% in 2005 to 110% by 2050 if no action is taken (CIE 2008; Höhne et al., 2017). Therefore, energy efficiency upgrading of the existing building stock plays a crucial role in reducing energy demand and the associated CO2 emissions. Energy and economic analysis of environmental upgrading of existing office buildings due to climate change on working days. Consequently, CO2 emissions and pollution will also increase. Lecamwasam (2014) also suggests that HVAC systems in older buildings can waste approximately 20 to 40% of total energy consumption. Therefore, in achieving the efficient use of energy and reducing CO2 emissions relating to indoor thermal comfort, conventional air- conditioned offices have to be upgraded to improve productivity and maintain a comfortable work environment (Barlow and Fiala, 2007; Kwon, Chun and Kwak, 2011; Au-Yong, Ali and Ahmad, 2014). Artificial lighting is another important area to improve energy efficiency in buildings. In the life of a building, the combined HVAC and lighting accounts for about 80% of total energy use during the operating stage (Juan, Gao and Wang, 2010; Abdallah and El-Rayes, 2015; DIS, 2015). In existing office buildings, the lighting systems that include inefficient lamps and fixtures can be upgraded with more energy effective ones or by eliminating the use of unnecessary lamps. Daylighting in office buildings is broadly considered an important design strategy of energy preservation that demanded cautious architectural design to satisfy that optimum benefits are achieved (Ko, Elnimeiri and Clarke, 2008; Raimondia et al., 2016). Improving the lighting load will not only reduce annual energy consumption but also reduce heat gains in buildings. The reduction of electricity consumption in office buildings can be achieved with proper design, which integrates daylight and artificial lighting systems. Thus, building energy expenses can be affected by two key climatic factors, solar radiation and outdoor illuminance, which can cool the buildings without the use of electricity where there is a proper strategic plan (Li, Lam and Wong, 2006; Li et al., 2009). Another factor affecting the effectiveness of the lighting system in office buildings is that the lighting system continuously interacts with the HVAC system. To improve energy efficiency for heating in the winter and reducing energy use for cooling in summer, the upgrading of the lighting systems must be coordinated with HVAC systems (Juan, Gao and Wang, 2010; Abdallah and El-Rayes, 2015; Regnier et al., 2018). Due to daylight constantly being associated with solar heat gain, when design levels exceed the space luminance required, solar heat gains will increase, and consequently, the electrical cooling load will also increase (Li, Lam and Wong, 2006; Li et al., 2009). Energy efficiency upgrading activities A way to minimise adverse environmental impacts is the upgrading of building systems or components (Abdallah and El-Rayes, 2015). As stated previously, the HVAC system consumes a significant amount of energy and it is a crucial element that provides the required indoor comfort (Lecamwasam, Wilson and Chokolich, 2012). The quality of indoor air has negative and positive effects on the productivity of users, in particular occupant health and safety. According to Barlow and Fiala (2007), by 2050, buildings which installed conventional HVAC systems will increase energy use by more than 20% to provide the required indoor comfort Construction Economics and Building, Vol. 20, No. 4, December 2020 86 Energy and economic analysis of environmental upgrading of existing office buildings Research method The research aims at undertaking an economic analysis of energy efficiency upgrade of existing office buildings. The literature review identified ten activities that are commonly upgraded, and details are summarised in Table 1. Economic analysis of energy efficiency upgrade is important as a budgetary constraint is one of the major barriers to the upgrading of existing office buildings. Three case studies are used to analyse the economic impact of different upgrading activities. The case studies involve three existing office buildings in Sydney, Australia, selected to illustrate the potential economic impact of energy efficiency upgrades. Energy and economic analysis of environmental upgrading of existing office buildings When a large office building is upgraded with an automation system, such as building management and control systems (BMCS), a savings of 30% can be achieved from energy consumption (Colmenar-Santos et al., 2013). It can be expected that the initial capital outlay for becoming green can be recovered by decreasing long-term energy costs. The literature review has identified areas that are commonly upgraded to improve energy efficiency of existing office buildings and are summarised in Table 1. The table presents the upgrading activities that have contributed to reducing energy consumption and CO2 emissions. The potential savings in the table may vary according to various variables such as climatic situation, geographical location of buildings, size, shape, operating and physical conditions of individual buildings, and should be considered as a guide only. From the table installing dimming control to the lighting system is found to have the most potential savings, followed by upgrading to the HVAC, BMCS, lifts and escalators, and replacing conventional hot water supply with a solar-boosted hot water system. 87 Construction Economics and Building, Vol. 20, No. 4, December 2020 Ding, Nguyen and Runeson Table 1 Summary of energy efficiency of common upgrading activities in office buildings Energy and economic analysis of environmental upgrading of existing office buildings Australia commercial building grading that represent high quality office buildings in the CBD (PCA, 2019). These three buildings were considered the best suited for the study due to the following reasons: • These buildings range from 24 to 33 years old represents a suitable range of ages for the investigation as literature review reveals that buildings within this range are due for refurbishment or upgrade (Burroughs, 2018). • They are medium and high-rise office buildings having gross floor area (GFA) from 17,000m2 to 45,000m2. • The three case study buildings have annual energy consumption per GFA of 128, 103 and 135 kWh/m2/annum which is considered high (Hestnes and Kofoed, 2002; Steinfeld, Bruce and Watt, 2011). Therefore, these buildings have opportunities for improvement in the annual usage and savings on energy and CO2 emissions The maintenance and upgrade records and three years of utility bills (2015-2018) from the facility management department were collected from each building. Additional data were also collected from meetings with facility managers and site visits to each building to examine building conditions and investigation into the maintenance and renovation records. Table 2 Characteristics of the three case study buildings Table 2 Characteristics of the three case study buildings Table 2 Characteristics of the three case study buildings The GFA of Building 2 is about 127% more than that of Building 1 but about 13% smaller than Building 3. Even though Building 3 has the biggest GFA its average annual energy consumption and CO2 emissions are not much higher than Building 1 per m2. Building 2 has the best performance of 103 kWh/m2/year and 112 kg CO2/m2/year respectively for the average annual energy consumption and CO2 emissions. The GFA of Building 2 is about 127% more than that of Building 1 but about 13% smaller than Building 3. Even though Building 3 has the biggest GFA its average annual energy consumption and CO2 emissions are not much higher than Building 1 per m2. Building 2 has the best performance of 103 kWh/m2/year and 112 kg CO2/m2/year respectively for the average annual energy consumption and CO2 emissions. Case study buildings The case study buildings, located in the Sydney Central Business District (CBD), are referred to as Building 1, 2 and 3. The characteristics of the three buildings are summarised in Table 2. The three case study buildings are A-Grade buildings according to the Property Council of 88 Construction Economics and Building, Vol. 20, No. 4, December 2020 Energy and economic analysis of environmental upgrading of existing office buildings Potential energy savings and economic analysis of upgrading activities The principal concern in upgrading an office building is financial; however, the other factor that should be considered in decision-making is the environmental impacts. Key stakeholders may be reluctant to invest money to improve their existing buildings. They face uncertainty about the long-term benefits of their investment. Financial concerns can prevent or delay Construction Economics and Building, Vol. 20, No. 4, December 2020 89 Ding, Nguyen and Runeson stakeholders in improving buildings due to the required capital outlays (Ellison and Sayce, 2007; Sev, 2009). Therefore, for energy efficiency upgrade to be implemented in an existing office building, affordability and long-term financial return must be included in the decision making In the assessment of economic impact and potential energy savings in the case study, the analysis concentrates on estimating the costs and savings of upgrading in the areas identified from the literature review to improve energy efficiency of buildings. The estimated costs and savings of upgrading are based on the data from research studies and published data. The annual costs of upgrading are calculated in cost per square metre ($/m2), and savings are by percentage (%) on energy consumption and CO2 emissions. The end-use shares of energy consumed in office buildings are computed for electricity use only as gas consumption is very little in this type of building (DIS, 2015). Construction Economics and Building, Vol. 20, No. 4, December 2020 1  Tenancy space is defined as an office space occupied by individual tenants for their intended business Estimating potential energy savings of upgrading activities The energy savings are based on savings on building services running on normal and peak loads. The energy savings calculated are the end-use of energy consumption per annum. The upgrading activities for energy efficiency and potential savings in the table were derived from the literature review and published data on a typical office building in Australia for the base building load only. Tenancy spaces1 were excluded from the study. Table 3 is developed based on the information in Table 1. Table 3 presents the calculation of the percentage savings on various upgrading activities. According to the Department of Industry and Science (DIS, 2015), the peak electricity demand in office buildings (base building load) is HVAC accounting for 67%, lighting for 16%, equipment for 11%, domestic hot water for 2% and others for 4%. Table 3 Summary of energy efficiency upgrading in office buildings (Base building load) Table 3 Summary of energy efficiency upgrading in office buildings (Base building load) Table 3 Summary of energy efficiency upgrading in office buildings (Base building load) In the table, Column 3 represents the energy consumption distribution of a typical office building and it indicates that HVAC consumes the most electricity, followed by lighting. The fourth column shows the estimated savings in percentage should the systems be upgraded. 1  Tenancy space is defined as an office space occupied by individual tenants for their intended business. Construction Economics and Building, Vol. 20, No. 4, December 2020 90 Energy and economic analysis of environmental upgrading of existing office buildings Therefore, in considering the various energy demand per upgrade activity, the estimated annual savings (Column 4) is calculated by multiplying the potential savings (Column 2) with the energy consumption distribution (Column 3) in Table 3. From the table, a major upgrade of the HVAC generates the highest potential saving of 20%, followed by lighting dimming control of 7% in energy consumption. 2  GST is Goods and Services Tax in Australia levied on market transaction of goods and services, similar to VAT in UK. Analysing potential energy savings and upgrading costs for the case study buildings The maintenance and renovation records for the three buildings were collected and analysed. The analysis found that the following upgrading activities have been undertaken in the past three years: • Both Building 1 and 2 have upgraded BMCS • Building 2 and 3 have upgraded electrical/power switchgear • All three buildings have replaced all lightings to T5 Therefore, the analysis has focused on the rest of the upgrading activities as included in Tables 3 and 4. Table 5 summarises the estimated potential savings in energy consumption (kWh/ m2), CO2 emissions (kg CO2/m2) and energy cost ($/m2) for the three buildings. The potential annual savings on energy cost is calculated from the energy price of approximately $0.35/kWh adapted from WePowr (2019) and Synergy (2019) and multiplied with annual savings on energy consumption for each building. The annualised upgrading cost in the table includes both the capital and maintenance costs. The three case studies, with current ages from 24 to 33 years old, are all due for a major refurbishment within the next few years. This means that all items with lifespans of 15 and 30 years will have to be replaced in this process. Therefore, it provides a significant opportunity to improve the energy performance of these buildings. In the table, the highest savings on annual energy cost is the HVAC with a saving in the range of $7.2–$9.5/m2, followed by an automatic dimming of lighting ($2.7–$3.5/m2) and double glazing to windows ($2.2–$2.8/ m2). Similar outcomes can be found for the potential savings of energy consumption and CO2 emissions. When comparing annualised upgrading cost and the potential savings of energy cost after upgrading, only for BMCS, solar panels and motion sensors do savings outweigh the upgrading cost. All other activities have higher annualised upgrading cost than the potential saving in energy cost which may have tendered the upgrading unprofitable. However, the gap between upgrading cost and energy cost saving can be narrowed or reversed with the likely increases in the price of energy. The annualised upgrading cost and potential savings are also presented graphically in Figure 1. The annualised upgrading cost is presented from the lowest to highest ($/m2). The horizontal axis represents upgrading activities. The vertical axis on the left is the annualised upgrading cost ($/m2), ranging approximately from $0.1–39/m2. Estimating annualised upgrading costs The estimation of upgrading costs that include both capital and maintenance during the lifecycle of the building has been summarised and presented in Table 4. The capital costs in upgrading are priced as at 2019 in terms of $/m2 of GFA (excluding GST2 or VAT). The maintenance costs were developed from journal articles and building maintenance websites (Menzies and Wherrett, 2005; Kubba, 2010; Steinfeld, Bruce and Watt, 2011; CostWeb, 2019; Rawlinsons, 2019; WePowr, 2019; Synergy, 2019). However, according to Nalewaik and Venters (2009) and Wu (2010), there are no fixed costs in the maintenance of building service system. Annual maintenance costs may vary depending on the frequency in schedules, the size and operation of systems. Therefore, the maintenance cost for each upgrade activity is estimated from information from facility managers of each case study buildings with appropriate adjustment to suit. The lifespan of each system or equipment is also included in Table 4. It is expected that each system or equipment may need to be upgraded one or more times over the building’s lifecycle. To simplify the calculation, the upgrading cost is annualised on a 30-year study period at a discount rate of 5%. Table 4 Economic analysis of energy efficiency upgrading in office buildings (base building load) Table 4 Economic analysis of energy efficiency upgrading in office buildings (base building load) 2  GST is Goods and Services Tax in Australia levied on market transaction of goods and services, similar to VAT in UK. 91 Construction Economics and Building, Vol. 20, No. 4, December 2020 91 Construction Economics and Building, Vol. 20, No. 4, December 2020 Ding, Nguyen and Runeson In the table, the minor upgrade to HVAC and lighting have been left open due to significant variations in the type and size of upgrading activities. From the table, the highest annualised upgrading cost is the installation of double glazing to windows to reduce heat gain and loss in the building of approximately $39/m2 with an approximate potential saving of 6% on annual energy consumption and CO2 emission. While upgrading the entire HVAC system has an annualised cost of approximately $22/m2 but will give a saving on annual energy consumption and CO2 emissions of 20%. The lowest upgrading cost is the installation of BMCS with an annualised cost of $0.1/m2 for a potential savings of 3%. Analysing potential energy savings and upgrading costs for the case study buildings The vertical axis on the right shows the percentage of potential savings on energy consumption and CO2 emissions, which range from approximately 0.6–20%. 92 Construction Economics and Building, Vol. 20, No. 4, December 2020 Energy and economic analysis of environmental upgrading of existing office buildings Energy and economic analysis of environmental upgrading of existing office buildings Table 5 Summary of potential savings for the three buildings 93 Construction Economics and Building, Vol. 20, No. 4, December 2020 Ding, Nguyen and Runeson The budgetary constraint may dictate the upgrading activities to be undertaken or may even have forbidden energy efficiency upgrade of existing office buildings to take place. The figure presents the annualised upgrading costs from the least to the most expensive activities to suit the appropriate work for the budget allowed in improving a building. Each building can be independently assessed and upgrading criteria selected depending on its geographic location, type, use of equipment, operational and maintenance schedules. Improvements can start from basic and consider activities with lesser intervention through to Each building can be independently assessed and upgrading criteria selected depending on its geographic location, type, use of equipment, operational and maintenance schedules. Each building can be independently assessed and upgrading criteria selected depending on its geographic location, type, use of equipment, operational and maintenance schedules. Improvements can start from basic and consider activities with lesser intervention through to more major upgrading to one or more parts of a system rather than upgrading or replacing the entire system unless it is necessary. Improvements can start from basic and consider activities with lesser intervention through to more major upgrading to one or more parts of a system rather than upgrading or replacing the entire system unless it is necessary. Figure 1 Compare upgrading activities between annualised upgrading costs and potential energy savings over a 30-year period Figure 1 Compare upgrading activities between annualised upgrading costs and potential energy savings over a 30-year period The upgrading can start with basic activities such as upgrading BMCS to monitor building services, install solar panels to offset energy demand from the main grid, motion sensors to turn off lightings of unoccupied space and replace hot water supply with solar-boosted hot water systems. Upgrading these basic activities can contribute approximately 10% reduction of energy consumption and the associated CO2 emission with an annualised upgrading cost of $1.8/m2. Analysing potential energy savings and upgrading costs for the case study buildings With a more generous budget, more expensive upgrading activities can take place to achieve more reduction. A major upgrade to the HVAC system and installation of automatic dimming control can lead to a potential reduction of energy consumption and CO2 emissions by approximately 28% with an annualised upgrading cost of $31.4/m2. However, for more expensive upgrading activities such as double glazing to windows, upgrading can be undertaken to part of the system only. In most cases, HVAC systems can be upgraded partially by replacing components such as cooling towers, chillers, or air handling units with more efficient alternatives. fi The results of the analysis are also presented in Table 6 to compare the outcomes of the three buildings. Building 1 has the highest annualised upgrading costs of $95/m2 with potential annual savings on the energy cost of $19/m2. Buildings 2 and 3 have similar annualised upgrading costs of approximately $76/m2. However, Building 3 generates more potential annual energy cost savings of $21/m2, approximately 29% more than Building 2 with the same amount of investment. Construction Economics and Building, Vol. 20, No. 4, December 2020 94 Energy and economic analysis of environmental upgrading of existing office buildings Energy and economic analysis of environmental upgrading of existing office buildings Table 6 Comparing annual potential savings of energy cost, energy consumption and CO2 emissions for the three buildings Case study building Annualised upgrading cost ($/m2) Potential savings after upgrading Energy cost* ($/m2) Energy consumption (kWh/m2) CO2 emissions (kg CO2/m2) 1 94.8 19.1 54.5 61.1 2 76.1 15 42.8 46.7 3 76.2 21 60.1 65.1 Note: * Energy cost refers to the savings on the cost of electricity consumption per annum on undertaking the upgrading activities as detailed in Table 2 Energy and economic analysis of environmental upgrading of existing office buildings Table 6 Comparing annual potential savings of energy cost, energy consumption and CO2 emissions for the three buildings Note: * Energy cost refers to the savings on the cost of electricity consumption per annum on undertaking the upgrading activities as detailed in Table 2 With regards to energy consumption and CO2 emissions, Building 2 outperforms the other two buildings. Building 2 is lower in energy consumption by approximately 22% and 29%, CO2 emission by approximately 24% and 28% respectively for Buildings 1 and 3. Analysing potential energy savings and upgrading costs for the case study buildings With the upgrading activities in the table, Building 1 can be improved to achieve total potential annual savings of approximately 55 kWh/m2 of energy consumption and 61 kg CO2/m2 of CO2 emissions, which results in an annual saving of approximately $19/m2 of operating energy costs. The calculation can reduce the energy consumption of Building 1 from the annual average of 128 to approximately 73 kWh/m2 and CO2 emissions from 143 to approximately 82 kg CO2/m2 annually. In a similar context, Building 2 can be improved to achieve total potential annual savings of approximately 43 kWh/m2 of energy consumption and 47 kg CO2/m2 of CO2 emissions. The upgrading may result in an annual savings of approximately $15/m2 on energy costs. The upgrading activities can reduce the energy consumption of Building 2 from the original annual consumption of 103 to approximately 60 kWh/m2 and CO2 emissions from 112 to approximately 65 kg CO2/m2 per annum. Building 3 can also be improved to achieve total potential annual savings of approximately 60 kWh/m2 of energy consumption and 65 kg CO2/ m2 CO2 emissions which results in an annual savings of approximately $21/m2 on energy costs. The upgrading activities can reduce the energy consumption of Building 3 from the average annual consumption of 135 to approximately 75 kWh/m2 and CO2 emissions from 147 to approximately 82 kg CO2/m2 per year. Compliance with the Australian government energy efficiency policy The sustainability agenda in green office buildings in Australia have significant developments in recent years. This has been driven at all levels. Nationally, the government has implemented an energy efficiency policy and has introduced the Green Lease policy which requires tenant occupied buildings to have a low impact on the environment, such as a 4.5 star or higher in the National Australian Built Environment Rating Scheme (NABERS) energy rating (Bannister, 2012; Burroughs, 2018). Under the national energy program for Commercial Building Disclosure, from 1 November 2010, when selling or leasing an office space greater than 2,000 m2 sellers or lessors are required to obtain or disclose up-to-date NABERS energy 95 Construction Economics and Building, Vol. 20, No. 4, December 2020 95 Ding, Nguyen and Runeson ratings with the Building Energy Efficiency Certificates for all existing buildings (Newell, MacFarlane and Walker, 2014; DIS, 2015). According to the guidelines from the NABERS rating, a 2 stars NABERS is equivalent to the energy consumption of 150-190 kWh/m2/year whilst 5 stars rating accounts for 40- 80 kWh/m2/year (Steinfeld, Bruce and Watt, 2011; Bannister, 2012; DIS, 2015). The three case study buildings undertaking the upgrading activities in Table 6 can improve the energy performance from 3 stars to a 5 stars NABERS energy rating which could make a significant impact to improve performance of the existing building stock. The increased star rating of these buildings is likely to have better tenant retention with higher rents as potential tenants of office buildings would recognise the energy efficiency of NABERS rating which would help to pay for the costs of upgrading. The Australian building stock comprises many older buildings which consume great quantities of energy and produce a high rate of CO2 emission (Burroughs, 2018). Traditionally, to maintain its intended function a building must be well maintained and, particularly, have a major refurbishment every 20–25 years (Wilkinson and Reed, 2006). However, according to Wilkinson and Reed (2006), and Mulholland, Hartman and Plumb (2005), the average age of the office building stock in major CBDs throughout Australia varies from 25 to 31 years since construction or from 13 to 19 years since the last refurbishment; and the average age of office buildings in Sydney is 28 years and 19 years respectively. Existing building stock continues to contribute negatively to the environment and the well-being of users. Compliance with the Australian government energy efficiency policy Therefore, the current existing office buildings in Australia must be improved to meet environmental standards (Remøy and Wilkinson, 2012; Strachan and Banfill, 2012; Xu, Chan and Qian, 2012). With CBD office buildings being the primary focus for economic and financial activity in Australia, the existing office space accounts for approximately 25 million square metres (Newell, MacFarlane and Walker, 2014). For undertaking the upgrading activities as identified in the study, a potential saving of 4,7222,300 GJ and 1,440,750 t CO2 of energy consumption and CO2 emissions could be achieved each year. Construction Economics and Building, Vol. 20, No. 4, December 2020 Energy and economic analysis of environmental upgrading of existing office buildings m2/year respectively for Building 1, 2 and 3. The energy efficiency of the three buildings could be improved from 3 stars to 5 stars NABERS Energy rating. The improved 5 stars NABERS Energy rating of the three case study buildings can achieve the requirement set by the Commercial Building Disclosure stipulated by the government in 2011. From the study, the annualised upgrading costs still outweighed annual saving in energy cost in most activities. The likely increase in future energy prices is likely to improve the attractiveness of energy efficiency upgrade. In the long-term, the improvement in the energy efficiency of the existing building stock will no doubt benefit both the natural and man-made environment. i Creating sustainable buildings from existing office buildings is an attractive and important alternative to demolition and rebuilding as a means to entice tenants. It is argued that sustainability is the expected way forward where retrofitting or upgrading of mature buildings is seen as necessary to meet the environmental protection requirements. The sustainable improvement of existing office buildings would help in harmonising the growth of the economy and environmental protection. A balance must be achieved between protecting and improving the natural environment and contributing positively to the economy over the building’s lifecycle. Buildings which offer multiple uses that meet market demands will reduce vacancy rates and thus survive longer and stay competitive, yet, improving the sustainable performance of existing office buildings in a long-tern approach has been largely untapped. However, the paper has limitations similar to other case studies in the literature. The generalisation of research result is often difficult with case studies that are subjected to variances such as geographical location and climate conditions. The research focuses on economic and environmental aspects only while the social aspect is an equally important consideration for future research. Conclusion The paper examined and analysed the cost implication of energy efficiency upgrading of existing office buildings and a case study of three Sydney office buildings has been conducted to present research results. The objectives set for the study have been researched and addressed in the paper. Firstly, the paper identified and discussed ten upgrading activities that are commonly undertaken to improve energy efficiency of existing office buildings. These include upgrades to HVAC, BMCS, hot water systems, lightning, lifts, and escalators Secondly. The upgradings were applied to a case study of three buildings located in the Sydney CBD and varying in age from 24 to 33 years old. to demonstrate the potentials for significant improvement in reducing energy consumption and the associated CO2 emissions. As discussed in the paper, existing office building stock is largely dated and energy inefficient. The literature review indicates that an existing office building can be improved to meet environmental protection standards by upgrading that may be a better alternative than knocking down and rebuilding. When undertaking energy efficiency upgradings, the annual energy consumption (kWh/m2) and emissions (kg CO2/m2) can be significantly decreased. Most existing office buildings in Australia, especially in Sydney, are outdated. It was demonstrated in the case studies that by undertaking upgrading activities, energy consumption could be reduced by 55, 42 and 60 kWh/m2/year and CO2 emissions by 61, 47 and 65 kg CO2/ Construction Economics and Building, Vol. 20, No. 4, December 2020 96 References Abdallah, M. and El-Rayes, K., 2015. Optimizing the selection of building upgrade measures to minimize the operational negative environmental impacts of existing buildings. Building and Environment, 84(0), pp.32-43. https://doi.org/10.1016/j.buildenv.2014.10.010 Abdallah, M. and El-Rayes, K., 2015. Optimizing the selection of building upgrade measures to minimize the operational negative environmental impacts of existing buildings. Building and Environment, 84(0), pp.32-43. https://doi.org/10.1016/j.buildenv.2014.10.010 Anderson, T.R., Hawkins, E. and Jones, P.D., 2016. CO2, the greenhouse effect and global warming: from the pioneering work of Arrhenius and callendar to today’s earth system models. Endeavour, 40(3), pp.178-87. https://doi.org/10.1016/j.endeavour.2016.07.002 Anderson, T.R., Hawkins, E. and Jones, P.D., 2016. CO2, the greenhouse effect and global warming: from the pioneering work of Arrhenius and callendar to today’s earth system models. Endeavour, 40(3), pp.178-87. https://doi.org/10.1016/j.endeavour.2016.07.002 Atif, M.R. and Galasiu, D., 2003. Energy performance of daylight-linked automatic lighting control systems in large atrium spaces: report on two field-monitored case studies. Energy and Buildings, 35(5), pp 441-61 https://doi org/10 1016/s0378-7788(02)00142-1 Australian Building Code Board, 2004. Energy efficiency of building transport equipment. Canberra, Australia: The Australian Building Code Board. Au-Yong, C.P., Ali, A.S. and Ahmad, F., 2014. Improving occupants’ satisfaction with effective maintenance management of HVAC system in office buildings. Automation in Construction, 43(0), pp.31- 37. https://doi.org/10.1016/j.autcon.2014.03.013 Bannister, P., 2012. NABERS: Lessons from 12 years of performance-based ratings in Australia. Energy Systems Laboratory, Proceedings of the 12th International Conference for Enhanced Building Operations. Manchester, UK. October. Barlow, S. and Fiala, D., 2007. Occupant comfort in UK offices-how adaptive comfort theories might influence future low energy office refurbishment strategies. Energy and Buildings, 39(7), pp.837-46. https://doi.org/10.1016/j.enbuild.2007.02.002 Construction Economics and Building, Vol. 20, No. 4, December 2020 97 Ding, Nguyen and Runeson Bondanza, J., 2011. How to design and build a green office building: a complete guide to making your new of existing building environmentally healthy. Florida, USA: Atlantic Publishing Group. Bourgeois, D., Reinhart, C. and MacDonald, I., 2006. Adding advanced behavioural models in whole building energy simulation: a study on the total energy impact of manual and automated lighting control. Energy and Buildings, 38(7), pp.814-23. https://doi.org/10.1016/j.enbuild.2006.03.002 Bruce, B., Zuo, J., Rameezdeen, R. and Pullen, S., 2015. Factors influencing the retrofitting of existing office buildings using Adelaide, South Australia as a case study. Structural Survey, 33(2), pp.150-66. https://doi.org/10.1108/ss-05-2014-0019 Bullen, P.A., 2007. Adaptive reuse and sustainability of commercial buildings. Facilities, 25(1/2), pp.20-31. https://doi.org/10.1108/02632770710716911 Burroughs, S., 2018. Improving office building energy-efficiency ratings using a smart-engineering– computer-simulation approach: an Australian case study. h enpol.2009.03.057 Chan, H.K,. Wang, X. and Raffoni, A., 2014. An integrated approach for green design: life-cycle, fuzzy AHP and environmental management accounting. The British Accounting Review, 46(4), pp.344-60. https://doi.org/10.1016/j.bar.2014.10.004 CIE, 2009. The buildings sector and greenhouse: key facts. Canberra: The Centre for International Economics.. Clarke, R., 2009. Global warming and Australia’s big dry. Green Left Weekly, 809, pp.12-15. Cleugh, H., Smith, M.S., Battaglia, M. and Graham, P., 2011. Climate change: science and solutions for Australia. Collingwood, Victoria, Australia: CSIRO. Colmenar-Santos, A., Terán de Lober, L.N., Borge-Diez, D. and Castro-Gil, M., 2013. Solutions to reduce energy consumption in the management of large buildings. Energy and Buildings, 56(0), pp.66-77. https://doi.org/10.1016/j.enbuild.2012.10.004 References Advances in Building Energy Research, 12(2), pp.217-34. https://doi.org/10.1080/17512549.2017.1287127 Cabeza, L.F., Rincón, L., Vilariño, V., Pérez, G. and Castell, A. 2014. Life cycle assessment (LCA) and life cycle energy analysis (LCEA) of buildings and the building sector: a review. Renewable and Sustainable Energy Reviews, 29(0), pp.394-416. https://doi.org/10.1016/j.rser.2013.08.037 Chan, E.H.W., Qian, Q.K. and Lam, P.T.I., 2009. The market for green building in developed Asian cities–The perspectives of building design. Energy Policy, 37(8), pp.3061-70. https://doi.org/10.1016/j. enpol.2009.03.057 https://doi.org/10.1016/j.enbuild.2012.10.004 Connelly, P. and Adam, N., 2009. Retrofitting for sustainablility. Architecture Australia, 98(1), pp.105-07. CostWeb, 2019. Making predictions of construction costs. Sydney, Australia. CostWeb, 2019. Making predictions of construction costs. Sydney, Australia. De Almeida, A., Hirzel, S., Patrão, C., Fong, J. and Dütschke, E., 2012. Energy-efficient elevators and escalators in Europe: an analysis of energy efficiency potentials and policy measures. Energy and Buildings, 47(0), pp.151-58. https://doi.org/10.1016/j.enbuild.2011.11.053 De Almeida, A., Hirzel, S., Patrão, C., Fong, J. and Dütschke, E., 2012. Energy-efficient elevators and escalators in Europe: an analysis of energy efficiency potentials and policy measures. Energy and 2.2016.1218320 Huovila, P., Ala-Juusela, M., Melchert, L., Pouffary, S., Cheng, C.C., Ürge-Vorsatz, D., Koeppel, S. and Svenningsen, N., 2009. In: Yamamoto, J. and Graham, P. eds. Building and climate change: summary for decision-makers. [online] UNEP SBCI. Available at: https://ledsgp.org/wp-content/uploads/2015/07/ buildings-and-climate-change.pdf. Ibn-Mohammed, T., Greenough, R., Taylor, S., Ozawa-Meida, L. and Acquaye, A., 2013. Operational vs. embodied emissions in buildings—a review of current trends. Energy and Buildings, 66(0), pp.232-45. https://doi.org/10.1016/j.enbuild.2013.07.026 fi doi.org/10.1016/j.enpol.2013.10.041 Hinnells, M., Bright, S., Langley, A., Woodford, L., Schiellerup, P. and Bosteels, T., 2008. The greening of commercial leases. Journal of Property Investment and Finance, 26(6), pp.541-51. https://doi. org/10.1108/14635780810908389 Höhne, N., Kuramochi, T., Warnecke, C., Röser, F., Fekete, H., Hagemann, M., Day, T., Tewari, R., Kurdziel, M., Sterl, S. and Gonzales, S. 2017. The Paris Agreement: resolving the inconsistency between global goals and national contributions. Climate Policy, 17(1), pp.16-32. https://doi.org/10.1080/1469306 2.2016.1218320 Höhne, N., Kuramochi, T., Warnecke, C., Röser, F., Fekete, H., Hagemann, M., Day, T., Tewari, R., Kurdziel, M., Sterl, S. and Gonzales, S. 2017. The Paris Agreement: resolving the inconsistency between global goals and national contributions. Climate Policy, 17(1), pp.16-32. https://doi.org/10.1080/1469306 2.2016.1218320 fi Buildings, 47(0), pp.151-58. https://doi.org/10.1016/j.enbuild.2011.11.053 Department of Climate Change and Energy Efficiency, 2012. Baseline energy consumption and greenhouse Department of Climate Change and Energy Efficiency, 2012. Baseline energy consumption and greenhouse gas emissions in commercial buildings in Australia, Part 1. COAG [online] Available at: https://www. fi gas emissions in commercial buildings in Australia, Part 1. COAG [online] Available at: https://www. energy.gov.au/sites/default/files/baseline-energy-consumption-part_1-report-2012.pdf. DIS, 2015. Commercial building disclosure program review. Canberra, Australia: Department of Industry and Science. 98 Construction Economics and Building, Vol. 20, No. 4, December 2020 https://doi.org/10.1016/j.enbuild.2013.07.026 Ihm, P., Nemri, A. and Krarti, M., 2009. Estimation of lighting energy savings from daylighting. Building and Environment, 44(3), pp.509-14. https://doi.org/10.1016/j.buildenv.2008.04.016 Energy and economic analysis of environmental upgrading of existing office buildings Ellison, L. and Sayce, S., 2007. Assessing sustainability in the existing commercial property stock. Property Management, 25(3), pp.287-304. https://doi.org/10.1108/02637470710753648 Ellison, L. and Sayce, S., 2007. Assessing sustainability in the existing commercial property stock. Property Management, 25(3), pp.287-304. https://doi.org/10.1108/02637470710753648 , y , , g y g p p y Property Management, 25(3), pp.287-304. https://doi.org/10.1108/02637470710753648 Elmualim, A., Shockley, D., Valle, R., Ludlow, G. and Shah, S., 2010. Barriers and commitment of Elmualim, A., Shockley, D., Valle, R., Ludlow, G. and Shah, S., 2010. Barriers and commitment of facilities management profession to the sustainability agenda. Building and Environment, 45(1), pp.58-64. https://doi.org/10.1016/j.buildenv.2009.05.002 Galasiu, A.D. and Veitch, J.A., 2006. Occupant preferences and satisfaction with the luminous environment and control systems in daylit offices: a literature review. Energy and Buildings, 38(7), pp.728- 42. https://doi.org/10.1016/j.enbuild.2006.03.001 Galasiu, A.D. and Veitch, J.A., 2006. Occupant preferences and satisfaction with the luminous fi environment and control systems in daylit offices: a literature review. Energy and Buildings, 38(7), pp.728- 42. https://doi.org/10.1016/j.enbuild.2006.03.001 Häkkinen, T. and Belloni, K., 2011. Barriers and drivers for sustainable building. Building Research and Information 39(3) pp 239 55 https://doi org/10 1080/09613218 2011 561948 Häkkinen, T. and Belloni, K., 2011. Barriers and drivers for sustainable building. Building Research and Information, 39(3), pp.239-55. https://doi.org/10.1080/09613218.2011.561948 Information, 39(3), pp.239-55. https://doi.org/10.1080/09613218.2011.561948 Henderson, H., 2006. Wanted for lease: 6 star office. ECOS, 131, pp.8-11. Hestnes, A.G. and Kofoed, N.U., 2002. Effective retrofitting scenarios for energy efficiency and comfort: Hestnes, A.G. and Kofoed, N.U., 2002. Effective retrofitting scenarios for energy efficiency and comfort: results of the design and evaluation activities within the OFFICE project. Building and Environment, 37(6), pp.569-74. https://doi.org/10.1016/s0360-1323(02)00003-3 Hestnes, A.G. and Kofoed, N.U., 2002. Effective retrofitting scenarios for energy efficiency and comfort: results of the design and evaluation activities within the OFFICE project. Building and Environment, Higgins, A., Syme, M., McGregor, J., Marquez, L. and Seo, S., 2014. Forecasting uptake of retrofit packages in office building stock under government incentives. Energy Policy, 65(0), pp.501-11. https:// doi.org/10.1016/j.enpol.2013.10.041 Kentwell, A., 2007. Climate change adaptation issues for planners. Australian Planner, 44(3), pp.20-21. https://doi.org/10.1080/07293682.2007.9982584 Kentwell, A., 2007. Climate change adaptation issues for planners. Australian Planner, 44(3), pp.20-21. https://doi.org/10.1080/07293682.2007.9982584 Ko, D.H., Elnimeiri, M. and Clarke, R.J., 2008. Assessment and prediction of daylight performance in high-rise office buildings. The Structural Design of Tall and Specific Buildings, 17(5), pp.953-76. https://doi. org/10.1002/tal.474 apenergy.2008.08.009 Li, D.H.W., Lam, T.N.T. and Wong, S.L., 2006. Lighting and energy performance for an office using high frequency dimming controls. Energy Conversion and Management, 47(9-10), pp.1133-45. https:// doi.org/10.1016/j.enconman.2005.06.016 Lynas, M., 2007. How to stop climate change: the easy way. New Statesman, 136(4870), pp.24-28. Menzies, G.F. and Wherrett, J.R., 2005. Multiglazed windows: potential for savings in energy, emissions and cost. Building Services Engineering Research and Technology, 26(3), pp.248-59. https://doi. Menzies, G.F. and Wherrett, J.R., 2005. Multiglazed windows: potential for savings in energy, Menzies, G.F. and Wherrett, J.R., 2005. Multiglazed windows: potential for savings in energy, emissions and cost. Building Services Engineering Research and Technology, 26(3), pp.248-59. https://doi. org/10.1191/0143624405bt132tn fi org/10.1002/tal.474 Kohler, N. and Yang, W., 2007. Long-term management of buildings stock. Building Research & Information, 35(4), pp.351-62. https://doi.org/10.1080/09613210701308962 Kubba, S., 2010. Green construction project management and cost oversight. Oxford, UK: Architectural Press. Kwon, S.H., Chun, C. and Kwak, R.Y., 2011. Relationship between quality of building maintenance management services for indoor environmental quality and occupant satisfaction. Building and Environment, 46(11), pp.2179-85. https://doi.org/10.1016/j.buildenv.2011.04.028 Lecamwasam, L., 2014. Commissioning HVAC systems: quick, cost-effective energy efficiency. Available at http://esbsconsult.com.au/wp-content/uploads/2014/11/Commissioning-HVAC-Systems-FM- Magazine.pdf Lecamwasam, L., Wilson, J. and Chokolich, D., 2012. Guide to best practice maintenance & operation of HVAC systems for energy efficiency. Canberra, Australia: COAG and DCCEE. Li, B. and Yao, R., 2009. Urbanisation and its impact on building energy consumption and efficiency in China. Renewable Energy, 34, pp.1994-98. https://doi.org/10.1016/j.renene.2009.02.015 Li, D.H.W., Lam, T.N.T., Chan, W.W.H. and Mak, A.H.L., 2009. Energy and cost analysis of semi- transparent photovoltaic in office buildings. Applied Energy, 86(5), pp.722-29. https://doi.org/10.1016/j. apenergy.2008.08.009 Ihm, P., Nemri, A. and Krarti, M., 2009. Estimation of lighting energy savings from dayligh and Environment, 44(3), pp.509-14. https://doi.org/10.1016/j.buildenv.2008.04.016 and Environment, 44(3), pp.509-14. https://doi.org/10.1016/j.buildenv.2008.04.016 IPCC, 2007. Climate change 2007: synthesis report, Contribution of Working Groups I, II and III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Pachauri, R.K. and Reisinger, A. eds. Geneva, Switzerland. IPCC, 2014. Climate change 2014: synthesis report, Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Pachauri, R.K. and Meyer, L.A. eds. Geneva, Switzerland. Ive, G., 2006. Re-examining the costs and value ratios of owning and occupying buildings. Building Research and Information, 34(3), pp.230-45. https://doi.org/10.1080/09613210600635192 Ive, G., 2006. Re-examining the costs and value ratios of owning and occupying buildings. Building Research and Information, 34(3), pp.230-45. https://doi.org/10.1080/09613210600635192 Construction Economics and Building, Vol. 20, No. 4, December 2020 99 Ding, Nguyen and Runeson Jenkins, D., Liu, Y. and Peacock, A.D., 2008. Climatic and internal factors affecting future UK office heating and cooling energy consumptions. Energy and Buildings, 40, (5), pp.874-81. https://doi. org/10.1016/j.enbuild.2007.06.006 org/10.1016/j.enbuild.2007.06.006 Jentsch, M.F., James, P.A.B. and Bahaj, A.S., 2010. A climatic envelope extension of an office building - perception and reality of the change in environments conditions. In: Proceedings CIBSE National Conference. Sustainable Energy Research Group, School of Civil Engineering and the Environment, University of Southampton, UK, March 21-22. - perception and reality of the change in environments conditions. In: Proceedings CIBSE National Conference. Sustainable Energy Research Group, School of Civil Engineering and the Environment, University of Southampton, UK, March 21-22. Juan, Y.K., Gao, P. and Wang, J., 2010. A hybrid decision support system for sustainable office building renovation and energy performance improvement. Energy and Buildings, 42(3), pp.290-97. https://doi. org/10.1016/j.enbuild.2009.09.006 Nicol, J.F., 2009. Cooling in a low carbon world. Building Research & Information, 37(4), pp.345-47. https://doi.org/10.1080/09613210902920714 Nicol, J.F., 2009. Cooling in a low carbon world. Building Research & Information, 37(4), pp.345-47. https://doi.org/10.1080/09613210902920714 PCA, 2019. A guide to office building quality. 3rd Edition. Sydney, NSW: Property Council Australia. PCA, 2019. A guide to office building quality. 3rd Edition. Sydney, NSW: Property Council Australia. Pitt, M., Tucker, M., Riley, M. and Longden, J., 2009. Towards sustainable construction: promotion and best practices. Construction Innovation, 9(2), pp.201-24. https://doi.org/10.1108/14714170910950830 PCA, 2019. A guide to office building quality. 3rd Edition. Sydney, NSW: Property Council Australia. Pitt, M., Tucker, M., Riley, M. and Longden, J., 2009. Towards sustainable construction: promotion and best practices. Construction Innovation, 9(2), pp.201-24. https://doi.org/10.1108/14714170910950830 Pitt, M., Tucker, M., Riley, M. and Longden, J., 2009. Towards sustainable construction: promotion and best practices. Construction Innovation, 9(2), pp.201-24. https://doi.org/10.1108/14714170910950830 Pitt, M., Goyal, S. and Sapri, M., 2006. Innovation in facilities maintenance management. Pitt, M., Goyal, S. and Sapri, M., 2006. Innovation in facilities maintenance management. Building Services Engineering Research & Technology, 27(2), pp.153-64. https://doi. Pitt, M., Goyal, S. and Sapri, M., 2006. Innovation in facilities maintenance management. Building Services Engineering Research & Technology, 27(2), pp.153-64. https://doi. Building Services Engineering Research & Technology, 27(2), pp.153-64. https://doi. Energy and economic analysis of environmental upgrading of existing office buildings Newell, G., MacFarlane, J. and Walker, R., 2014. Assessing energy rating premiums in the performance of green office buildings in Australia. Journal of Property Investment and Finance, 32(4), pp.352-70. https://doi.org/10.1108/jpif-10-2013-0061 org/10.1191/0143624405bt132tn Mulholland, V., Hartman, A. and Plumb, C., 2005. Building refurbishment - repositioning your asset for success. Australian Property Journal, 38(7), pp.506-15. Nalewaik, A. and Venters, V., 2009. Cost benefits of building green. Cost Engineering, 51(1), pp.28-34. 100 Construction Economics and Building, Vol. 20, No. 4, December 2020 org/10.1016/j.enbuild.2017.10.090 Remøy, H.T. and Wilkinson, S.J., 2012. Office building conversion and sustainable adaptation: a comparative study. Property Management, 30(3), pp.218-31. https://doi.org/10.1108/02637471211233738 Remøy, H.T. and Wilkinson, S.J., 2012. Office building conversion and sustainable adaptation: a comparative study. Property Management, 30(3), pp.218-31. https://doi.org/10.1108/02637471211233738 Roisin, B., Bodart, M., Deneyer, A. and D’Herdt, P., 2008. Lighting energy savings in offices using different control systems and their real consumption. Energy and Buildings, 40(4), pp.514-23. https://doi. org/10.1016/j.enbuild.2007.04.006 Roisin, B., Bodart, M., Deneyer, A. and D’Herdt, P., 2008. Lighting energy savings in offices using different control systems and their real consumption. Energy and Buildings, 40(4), pp.514-23. https://doi. org/10.1016/j.enbuild.2007.04.006 org/10.1191/0143624406bt153oa Raimondia, A., Santuccib, D., Bevilacquaa, S. and Corsoa, A., 2016. Daylight autonomy as a driver for office building retrofitting. Energy Procedia, 96, pp.180-89. https://doi.org/10.1016/j.egypro.2016.09.119 Rawlinsons, 2019. Australian Construction Handbook. Perth, Western Australia: Rawlinsons Publishing. Regnier, C., Sun, K., Hong, T. and Piette, M.A., 2018. Quantifying the benefits of a building retrofit using an integrated system approach: a case study. Energy and Building, 159, pp.332-45. https://doi. org/10.1016/j.enbuild.2017.10.090 Raimondia, A., Santuccib, D., Bevilacquaa, S. and Corsoa, A., 2016. Daylight autonomy as a driver for office building retrofitting. Energy Procedia, 96, pp.180-89. https://doi.org/10.1016/j.egypro.2016.09.119 f org/10.1016/j.enbuild.2007.04.006 Sev, A., 2009. How can the construction industry contribute to sustainable development? A conceptual framework. Sustainable Development, 17(3), pp.161-73. https://doi.org/10.1002/sd.373 Snodgrass, K., 2008. Life-cycle cost analysis for buildings is easier than you thought. Missoula, MT: U.S. Department of Agriculture Forest Service Technology and Development Center. Steinfeld, J., Bruce, A. and Watt, M., 2011. Peak load characteristics of Sydney office buildings and policy recommendations for peak load reduction. Energy and Buildings, 43(9), pp.2179-87. https://doi. org/10.1016/j.enbuild.2011.04.022 Strachan, M. and Banfill, P., 2012. Decision support tools in energy-led, non-domestic building refurbishment-towards a generic model for property professionals. Facilities, 30(9-10), pp.374-95. https:// doi.org/10.1108/02632771211235215 Synergy, 2019. Standard electricity prices and charges. [online] Available at https://www.synergy.net.au/ Your-business/Energy-products/Electricity-plans/Synergy-Business-Saver?tid=Energy-products:side_ nav:Business Saver. Synergy, 2019. Standard electricity prices and charges. [online] Available at https://www.synergy.net.au/ Your-business/Energy-products/Electricity-plans/Synergy-Business-Saver?tid=Energy-products:side_ nav:Business Saver. Taylor, R., 2009. Old buildings take the green lead. ECOS, 148, pp. 24-7. Ürge-Vorsatz, D., Harvey, L.D., Mirasgedis, S. and Levine, M.D., 2007. Mitigating CO2 emissions from energy use in the world’s buildings. Building Research and Information, 35(4), pp.379-98. https://doi. org/10.1080/09613210701325883 101 Construction Economics and Building, Vol. 20, No. 4, December 2020 Ding, Nguyen and Runeson Ürge-Vorsatz, D., Koeppel, S. and Mirasgedis, S., 2007. Appraisal of policy instrument for reducing buildings’ CO2 emmissions. Building Research and Information, 35(4), pp.458-77. https://doi. org/10.1080/09613210701327384 Wan, K.K.W., Li, D.H.W., Pan, W. and Lam, J,C., 2012. Impact of climate change on building energy use in different climate zones and mitigation and adaptation implications. Applied Energy, 97(0), pp.274- 82. https://doi.org/10.1016/j.apenergy.2011.11.048 WePowr, 2019. How much maintenance to solar hot water systems require? [online] Available at http:// wepowr.com/technology/shw/maintenance. Wild, A., 2008. Green collar workforce the key to a triple bottom line. ECOS, 146, pp.17. Wilkinson, S., 2014. The preliminary assessment of adaptation potential in existing office buildings. I t ti l J l f St t i P p t M t 18(1) 77 87 htt //d i /10 3846/164871 Wilkinson, S., 2014. The preliminary assessment of adaptation potential in existing office buildings. International Journal of Strategic Property Management, 18(1), pp.77-87. https://doi.org/10.3846/164871 5x.2013.853705 5x.2013.853705 Wilkinson, S.J. and Reed, R.G., 2006. Office building characteristics and the links with carbon emissions. Structural Survey, 24(3), pp.240-50. https://doi.org/10.1108/02630800610678887 Wilson, J.L. and Tagaza, E., 2006. Green buildings in Australia: drivers and barriers. Australian Journal of Structural Engineering, 7(1), pp.57-63. https://doi.org/10.1080/13287982.2006.11464964 Wright, R., 2009. Old buildings take the green lead. ECOS, 148, pp.24-27. Wu, S., 2010. Research opportunities in maintenance of office building services systems. Journal of Quality in Maintenance Engineering, 16(1), pp.23-33. https://doi.org/10.1108/13552511011030309 Xu, P.P. ,Chan, E.H.W. and Qian, Q.K., 2012. Key performance indicators (KPI) for the sustainability of building energy efficiency retrofit (BEER) in hotel buildings in China. Facilities, 30(9-10), pp.432-48. https://doi.org/10.1108/02632771211235242 Zhou, Z., Zhang, S., Wang, C., Zuo, J. and He, Q. and Rameezdeen, R., 2016. Achieving energy efficient buildings via retrofitting of existing buildings: a case study. Journal of Cleaner Production, 112, pp.3605-15. https://doi.org/10.1016/j.jclepro.2015.09.046 Zografakis, N., Karyotakis, K. and Tsagarakis, K.P., 2012. Implementation conditions for energy saving technologies and practices in office buildings: Part 1 lighting. Renewable and Sustainable Energy Reviews, 16(6), pp.4165-74. https://doi.org/10.1016/j.rser.2012.03.005 Zografakis, N., Karyotakis, K. and Tsagarakis, K.P., 2012. Implementation conditions for energy saving technologies and practices in office buildings: Part 1 lighting. Renewable and Sustainable Energy Reviews, 16(6), pp.4165-74. https://doi.org/10.1016/j.rser.2012.03.005 102 Construction Economics and Building, Vol. 20, No. 4, December 2020
https://openalex.org/W2807610638
https://archimer.ifremer.fr/doc/00489/60078/63402.pdf
English
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Data-Driven Interpolation of Sea Level Anomalies Using Analog Data Assimilation
Remote sensing
2,019
cc-by
11,675
Received: 21 January 2019; Accepted: 4 April 2019; Published: 9 April 2019 Abstract: From the recent developments of data-driven methods as a means to better exploit large-scale observation, simulation and reanalysis datasets for solving inverse problems, this study addresses the improvement of the reconstruction of higher-resolution Sea Level Anomaly (SLA) fields using analog strategies. This reconstruction is stated as an analog data assimilation issue, where the analog models rely on patch-based and Empirical Orthogonal Functions (EOF)-based representations to circumvent the curse of dimensionality. We implement an Observation System Simulation Experiment (OSSE) in the South China Sea. The reported results show the relevance of the proposed framework with a significant gain in terms of Root Mean Square Error (RMSE) for scales below 100 km. We further discuss the usefulness of the proposed analog model as a means to exploit high-resolution model simulations for the processing and analysis of current and future satellite-derived altimetric data with regard to conventional interpolation schemes, especially optimal interpolation. Keywords: analog data assimilation; sea level anomaly; sea surface height; interpolation; data-driven methods Redouane Lguensat 1,* , Phi Huynh Viet 2, Miao Sun 3, Ge Chen 4, Tian Fenglin 4 , Bertrand Chapron 5 and Ronan Fablet 2 Redouane Lguensat 1,* , Phi Huynh Viet 2, Miao Sun 3, Ge Chen 4, Tian Fenglin 4 , Bertrand Chapron 5 and Ronan Fablet 2 1 IGE, Université Grenoble Alpes, CNRS, IRD, Grenoble INP, 38000 Grenoble, France 2 IMT Atlantique, Lab-STICC UMR CNRS 6285, UBL, 29200 Brest, France; Vietphi3892@gmail.com (P.H. ronan.fablet@imt-atlantique.fr (R.F.) q ( ) 3 Key Laboratory of Digital Ocean, National Marine Data and Information Service, Tianjin 300171, China; miaomiao_1987qq@126.com 3 Key Laboratory of Digital Ocean, National Marine Data and Information Service, Tianjin 300171, China; miaomiao_1987qq@126.com qq 4 Department of Marine Information Technology, Ocean University of China, Qingdao 266100, China; gechen@ouc.edu.cn (G.C.); tianfenglin@ouc.edu.cn (T.F.) 4 Department of Marine Information Technology, Ocean University of China, Qingdao 266100, China; gechen@ouc.edu.cn (G.C.); tianfenglin@ouc.edu.cn (T.F.) 5 Laboratoire d’Océanographie Physique et Spatiale, IFREMER, 29200 Brest, France; bertrand.chapron@ifremer.fr * Correspondence: redouane.lguensat@univ-grenoble-alpes.fr remote sensing remote sensing remote sensing www.mdpi.com/journal/remotesensing 1. Introduction Typically, horizontal scales from a few tens of kilometers to ≈100 km may be poorly resolved by OI-derived SSH fields, while they may be partially revealed by along-track altimetric data. This has led to a variety of research studies to improve the reconstruction of the altimetric fields. One may cite both methodological alternatives to OI, for instance locally-adapted convolutional models [17] and variational assimilation schemes using model-driven dynamical priors [18], as well as studies exploring the synergy between different sea surface tracers, especially the synergy between SSH and SST (Sea Surface Temperature) fields and Surface Quasi-Geostrophic dynamics [17,19–23]. Q p y [ , ] In this work, we build upon our recent advances in analog data assimilation and its application to high-dimensional fields. While the works in [12,13] presented the AnDA framework by combining the analog forecasting method and stochastic filtering, these works have only shown applications to geophysical toy models. It was not until the work in [24] that the AnDA methodology was applied to realistic high dimensional fields, namely, Sea Surface Temperature (SST). Dealing with the curse of dimensionality is a critical challenge, in [24] we have shown that the use of patch-based representations (a patch is a term used by the image processing community to refer to smaller image parts of a given global image [25]) combined with EOF-based representations (EOF stands for Empirical Orthogonal Function, a classic dimensionality reduction technique also known as Principal Component Analysis (PCA)) leads to a computationally-efficient interpolation of missing data in SST maps outperforming classical OI-based interpolation schemes. Another development in AnDA applied to high dimensional fields was the introduction of conditional and physically-derived operators [26], where the analog forecasting operators account for the theoretical studies relating to synergies between ocean variables (e.g., SSH and SST) and those highlighting the importance of inter-scale dependencies. In this paper, we make use of these previously developed methodologies and tools and apply the AnDA to Sea Level Anomaly fields. 1. Introduction Over the last two decades, ocean remote sensing data has benefited from numerous remote earth observation missions. These satellites measured and transmitted data about several ocean properties, such as sea surface height, sea surface temperature, ocean color, ocean current, sea ice, etc. This has helped building big databases of valuable information and represents a major opportunity for the interplay of ideas between the ocean remote sensing community and the data science community. Exploring machine learning methods in general and non-parametric methods in particular is now feasible and is increasingly drawing the attention of many researchers [1,2]. More specifically, analog forecasting [3] which is among the earliest statistical methods explored in geoscience benefits from recent advances in data science. In short, analog forecasting is based on the assumption that the future state of a system can be predicted throughout the successors of past (or simulated) similar situations (called analogs). The amount of currently available remote sensing and simulation data offers analog methods a great opportunity to catch up their early promises. Several Remote Sens. 2019, 11, 858; doi:10.3390/rs11070858 www.mdpi.com/journal/remotesensing 2 of 22 Remote Sens. 2019, 11, 858 recent works involving applications of analog forecasting methods in geoscience fields contribute in the revival of these methods, recent applications comprise the prediction of soil moisture anomalies [4], the prediction of sea-ice anomalies [5], rainfall nowcasting [6], numerical weather prediction [7–9], etc. One may also cite methodological developments such as dynamically-adapted kernels [10] and novel parameter estimation schemes [11]. Importantly, analog strategies have recently been extended to address data assimilation issues within the so-called analog data assimilation (AnDA) [12,13], where the dynamical model is stated as an analog forecasting model and combined to state-of-the-art stochastic assimilation procedures such as Ensemble Kalman filters. Producing time-continuous and gridded maps of Sea Surface Height (SSH) is a major challenge in ocean remote sensing with important consequences on several scientific fields from weather and climate forecasting to operational needs for fisheries management and marine operations (e.g., [14]). The reference gridded SSH product commonly used in the literature is distributed by Copernicus Marine Environment Monitoring Service (CMEMS) (formerly distributed by AVISO+). This product relies on the interpolation of irregularly-spaced along-track data using an Optimal Interpolation (OI) method [15,16]. While OI is relevant for the retrieval of horizontal scales of SSH fields up to ≈100 km, the prescribed covariance priors lead to smoothing out finer-scales. 2.1. Model Simulation Data The Ocean General Circulation Model (OGCM) for the Earth Simulator (OFES) is considered in this study as the true state of the ocean. The simulation data is described in [27,28]. The coverage of the model is 75◦S–75◦N with a horizontal resolution of 1/10◦. 34 years (1979–2012) of 3-daily simulation of SSH maps are considered, we proceed to a subtraction of a temporal mean to obtain SLA fields. In this study, our region of interest is located in the South China Sea (105◦E to 117◦E, 5◦N to 25◦N). This dataset is split into a training dataset corresponding to the first 33 years (4017 SLA maps) and a test dataset corresponding to the last year of the time series (122 SLA maps). 1. Introduction The contribution of this work is two-fold: (i) Confronting AnDA to the reconstruction of an ocean tracer with scarce observations compared to SST (due to the nature of the available altimeters); (ii) designing an Observation System Simulation Experiment (OSSE) based on numerical simulation data to build the archived datasets used for the analog search; (iii) Reconstructing Sea Level Anomaly (SLA) by using SST or large scale SLA as auxiliary variables embedded in the analog regression techniques as shown in Section 4. Using OFES (Ocean General Circulation Model (OGCM) for the Earth Simulation) numerical simulations [27,28], we design an Observation System Simulation Experiment (OSSE) for a case-study in the South China Sea using real along-track sampling patterns of spaceborne altimeters. Several particular mesoscale variation patterns characterizing this region were studied in the literature, we refer the reader to [29] and references therein. We also note that our method is not region specific and can be 3 of 22 Remote Sens. 2019, 11, 858 applied to any region of interest. Using the resulting groundtruthed dataset, we perform a qualitative and quantitative evaluation of the proposed scheme, including comparisons to state-of-the-art schemes. The remainder of the paper is organized as follows: Section 2 presents the different datasets used in this paper to design an OSSE, Section 3 gives insights on the classical methods used for mapping SLA from along track data, Section 4 introduces the proposed analog data assimilation model. Experimental settings are detailed in section 5 and results for the considered OSSE are shown in Section 6. Section 7 further discusses the key aspects of this work. 2. Data: OFES (OGCM for the Earth Simulator) An Observation System Simulation Experiment (OSSE) based on numerical simulations is considered to assess the relevance of the proposed analog assimilation framework. Our OSSE uses these numerical simulations as a groundtruthed dataset from which simulated along-track data are produced. We describe further the data preparation setup in the following sections. 3.1. Data Assimilation and Optimal Interpolation 3.1. Data Assimilation and Optimal Interpolation Data assimilation consists in estimating the true state of a physical variable x(t) at a specific time t, by combining (i) equations governing the dynamics of the variable, (ii) available observations y(1, ..., T) measuring the variable and (iii) a background or first guess on its initial state xb. The estimated state is generally called the analyzed state and noted by xa. Data assimilation is a typical example of inverse problems, and similar formulations are known to the statistical signal processing community through optimal control and estimation theory [30]. We adopt here the unified notation of [31] and formulate the problem as a stochastic system in the following: ( x(t) = M(x(t −1)) + η(t), (1) y(t) = H(x(t)) + ϵ(t). (2) (1) (2) (1) (2) (2) Equation (1) represents the dynamical model governing the evolution of state x through time, while η is a Gaussian centered noise of covariance Q that models the process error. Equation (2) explains the relationship between the observation y(t) and the state to be estimated x(t) through the operator H. The uncertainty of the observation model is represented by the ϵ error, considered here to be Gaussian centered and of covariance R. We assume that ϵ and η are independent and that Q and R are known. Two main approaches are generally considered for the mathematical resolution of the system (1) and (2), namely, variational data assimilation and stochastic data assimilation. They differ in the way they infer the analyzed state xa, the first is based on the minimization of a certain cost function while the latter aims to obtain an optimal a posteriori estimate. We encourage the reader to consider the book of [32] for detailed insights on the various aspects and methods of data assimilation. A popular data assimilation algorithm that is largely used in the literature to grid sea level anomalies from along-track data is called Optimal Interpolation (OI) (e.g., [15,33]), this algorithm is also the method adopted in CMEMS altimetry product. Optimal Interpolation (OI) aims at finding the Best Linear Unbiased Estimator (BLUE) of a field x given irregularly sampled observations y in space and time and a background prior xb. The multivariate OI equations were derived in [34] for meteorology and numerous applications in oceanography have been reported since the early work of [16]. 2.2. Along Track Data We consider a realistic situation with a high rate of along track data. More precisely we use along-track data positions registered in 2014 where four satellites (Jason2, Cryosat2, Saral/AltiKa, HY-2A) were operating. Data is distributed by Copernicus Marine and Environment Monitoring Service (CMEMS). From the reference 3-daily SLA dataset and real along-track data positions, we generate simulated along-track data from the sampling of a reference SLA field: More precisely, for a given along-track point, we sample the closest position of the 1/10◦regular model grid at the closest time step of the 3-daily model time series. As we consider a 3-daily assimilation time step (see Section 2.1 for details), we create a 3-daily pseudo-observation field, to be fed directly to the assimilation model. For a given time t, we combine all along-track positions for times t −1, t and t + 1 to create an along-track pseudo-observation field at time t. We denote by s3dAT the simulated 3-daily time series of along-track pseudo-observation fields. An example of these fields is given in Figure 1. 4 of 22 Remote Sens. 2019, 11, 858 Ground Truth 114 oE 106 oE 108 oE 110 oE 112 oE 116 oE 8 oN 12 oN 16 oN 20 oN 24 oN -0.3 -0.2 -0.1 0 0.1 0.2 Simulated Along track 24 oN 20 oN 16 oN 12 oN 8 oN 116 oE 114 oE 112 oE 110 oE 108 oE 106 oE -0.3 -0.2 -0.1 0 0.1 0.2 Figure 1. An example of a ground-truth Sea Level Anomaly (SLA) field (meters) in the considered region and its associated simulated pseudo-along track. Ground Truth 114 oE E 108 oE 110 oE 112 oE 116 oE Figure 1. An example of a ground-truth Sea Level Anomaly (SLA) field (meters) in the considered region and its associated simulated pseudo-along track. 3.1. Data Assimilation and Optimal Interpolation Supposing that the background state xb has covariance B, and the observation operator is Remote Sens. 2019, 11, 858 5 of 22 linear H = H, the analyzed state xa and the analyzed error covariance Pa can be calculated using the following OI set of equations: K = BH(R + HBHT)−1 called the Kalman gain, (3) xa = xb + K(y −Hxb), (4) Pa = (I −KH)B. (5) (3) (3) (4) (5) (5) It is worth mentioning that [35] showed that OI is closely related to the 3D-Var variational data assimilation algorithm which obtains xa by minimizing the following cost function: J(x) = (x −xb)TB−1(x −xb) + (y −Hx)TR−1(y −Hx). (6) (6) An important limitation of OI is that the Gaussian-like covariance priors lead to smoothing out the small-scale information (e.g., mesoscale eddies), more specifically, this is a limitation due to the use of a static climatological B matrix. For satellite-derived altimetry fields, this usually results in over-smoothing altimetry fields for structures below ≈100 km [18]. This limitation may be even more critical in the context of future high-resolution altimetry missions, which supports the development of new OI-based methods (e.g., multi-scale OI schemes as in [36]) or alternatives as addressed by our work. 3.2. Analog Data Assimilation Endorsed by the recent development in data-driven methods and data storage capacities, the Analog Data Assimilation (AnDA) was introduced as an alternative to classical model-driven data assimilation under one or more of the following situations [13]: • The model is inconsistent with observations. • The model is inconsistent with observations. • The cost of the model integration is high computationally. The cost of the model integration is high computationally. • The cost of the model integration is high computationally. • (mandatory) The availability of a represenative (large) dataset of the dynamics of the state variables to be estimated. These datasets are hereinafter called catalogs and denoted by C. The catalog is organized in a two-column dictionary where each state of the system is associated with its successor in time, forming a set of couples (Ai, Si) where Ai is called the analog and Si its successor. Given the considerations above, AnDA resorts to evaluating filtering, respectively smoothing, posterior likelihood, i.e., the distribution of the state to be estimated x(t) at time t, given past and current observations y(1, ..., t), respectively given all the available observation y(1, ..., T). This evaluation relies on the following state-space model: ( x(t) = F(x(t −1)) + η(t), (7) y(t) = H(x(t)) + ϵ(t). (8) (7) (7) (8) (8) The difference between AnDA and classical data assimilation resides in the transition model Equation (7). The counterpart of a model-driven operator M of Equation (1) is here the operator F which refers to the considered data-driven operator, so called, the analog forecasting operator. This operator makes use of the available catalog C and assumes that the state forecast can be inferred from similar situations in the past. Provided the definitions of the analogs and successors given above, the derivation of this operator resorts to characterizing the transition distribution i.e., p(x(t)|x(t −1)). Following [13], a Gaussian conditional distribution is adopted: p(x(t)|x(t −1)) = N (µ(x(t −1)), Σ(x(t −1))), (9) (9) 6 of 22 Remote Sens. 2019, 11, 858 where N is a Gaussian distribution of mean µ(x(t −1)) and covariance Σ(x(t −1)). These parameters of the Gaussian distribution are calculated using the result of a K nearest neighbors search. 3.2. Analog Data Assimilation The K nearest neighbors (analogs) Ak∈(1,...,K) of state x(t −1) and their successors Sk∈(1,...,K), along with a weight associated to each pair (Ak, Sk) are used to calculate µ(x(t −1)) and Σ(x(t −1)) as we will show in the next paragraph, the forecast state x(t) is then sampled from N (µ(x(t −1)), Σ(x(t −1))). The weights are defined using a Gaussian kernel KG. KG (u, v) = exp  −∥u −v∥2 σ  . (10) (10) Scale parameter σ is locally-adapted to the median value of the K distances ∥x(t −1) −Ak∥2 to the K analogs. Other types of kernels might be considered (e.g., [4,10]), investigating kernel choice is out of the scope of this paper. The mean and the covariance of the transition distribution might be calculated following several strategies. We consider in this work the three analog forecasting operators introduced in AnDA [13], more details can be found in Appendix A: • Locally-constant operator: Mean µ(x(t −1)) and covariance Σ(x(t −1))) are given by the weighted mean and covariance of the K successors Sk∈(1,...,K). y p µ( ( )) ( ( ))) g weighted mean and covariance of the K successors Sk∈(1,...,K). • Locally-incremental operator: Here, the increments between the K analogs and their corresponding successors are calculated Sk∈(1,...,K) −Ak∈(1,...,K). The weighted mean of the K increments is then added to the x(t −1) to obtain µ(x(t −1)). While Σ(x(t −1))) results in the weighted covariance of these differences. • Locally-linear operator: A weighted least-square estimation of the linear regression of the state at time t given the state at time t −1 is performed based on the K pairs (Ak, Sk). The parameters of the linear regression are then applied to state x(t −1) to obtain µ(x(t −1)). Covariance Σ(x(t −1))) is represented by the covariance of the residuals of the fitted weighted linear regression. We may state clearly the key difference between the AnDA and reduced-rank Kalman filters and the OI method. It lies in the fact that the AnDA introduces a dynamical operator and not a prescribed space-time covariance model, and this dynamical operator is state-dependent and globally non-linear. The proposed analog forecasting operator can be seen as a state-dependent linear Gaussian operator, meaning that it is locally Gaussian and linear at each time step with a parameterization that depends on the current state, such that globally the dynamical operator is non-linear and non-Gaussian. 3.2. Analog Data Assimilation We may state clearly the key difference between the AnDA and reduced-rank Kalman filters and the OI method. It lies in the fact that the AnDA introduces a dynamical operator and not a prescribed space-time covariance model, and this dynamical operator is state-dependent and globally non-linear. The proposed analog forecasting operator can be seen as a state-dependent linear Gaussian operator, meaning that it is locally Gaussian and linear at each time step with a parameterization that depends on the current state, such that globally the dynamical operator is non-linear and non-Gaussian. A special case where AnDA is equivalent to OI is when all the elements of the catalog are considered as neighbors of any state vector. This case comes to assume that the dynamical operator is linear and state-independent. It is obviously of low interest due to the computational burden resulting from using all the catalog. A special case where AnDA is equivalent to OI is when all the elements of the catalog are considered as neighbors of any state vector. This case comes to assume that the dynamical operator is linear and state-independent. It is obviously of low interest due to the computational burden resulting from using all the catalog. The application of the AnDA framework faces the curse of dimensionality i.e., the search of analogs is highly affected by the dimensionality of the problem and can fail at finding good analogs for state vector dimensions above 20 [13]. As proposed in [24], the extension of AnDA models to high-dimensional fields may then rely on turning the global assimilation issue into a series of lower-dimensional ones. We consider here an approach similar to [24] using a patch-based and EOF-based representation of the two-dimensional (2D) fields, i.e., the 2D fields are decomposed into a set of overlapping patches, each patch being projected onto an EOF space. Analog strategies then apply to patch-level time series in the EOF space. Overall, as detailed in the following section, the proposed analog data assimilation model for SLA fields relies on three key components: A patch-based representation of the SLA fields, the selection of a kernel to retrieve analogs and the specification of a patch-level analog forecasting operator. 7 of 22 Remote Sens. 2019, 11, 858 4. Analog Reconstruction for Altimeter-Derived SLA 4.1. Patch-Based State-Space Formulation 4.2. Patch-Based Analog Dynamical Models Given the considered patch-based representation of field dX, the proposed patch-based analog assimilation scheme involves a dynamical model stated in the EOF space. Formally, Equation (9) leads to the following Gaussian conditional distribution in the EOF space: (13) p(Φ(Ps, t)|Φ(Ps, t −1)) = N (µ(Φ(Ps, t −1)), Σ(Φ(Ps, t −1))), (13) We consider the three analog forecasting operators presented in Section 3.2, namely, the locally-constant, the locally-incremental and the locally-linear. The calculation of the weights associated to each analog-successor pair relies on a Gaussian kernel KG (Equation (10)). The search for analogs in the NE-dimensional patch space (in practice, NE ranges from 5 to 20) ensures a better accuracy in the retrieval of relevant analogs compared to a direct search in the high-dimensional space of state dX. It also reduces the computational complexity of the proposed scheme. Another important extension of the current study is the possibility of exploiting auxiliary variables with the state vector Φ in the analog forecasting models. Such variables may be considered in the search for analogs as well as regression variables in a locally-linear analog setting. Regarding the targeted application to the reconstruction of SSH fields and the proposed two-scale decomposition (Equation (11)), two types of auxiliary variables seem to be of interest: The low-resolution component ¯X to take into account inter-scale relationship [17], and Sea Surface Temperature (SST) with respect to the widely acknowledged SST-SSH synergies [17,19,21]. We also apply patch-level EOF-based decompositions to include both types of variables in the considered analog forecasting models (Equation (13)). 4.1. Patch-Based State-Space Formulation As stated above, OI may be considered as an efficient model-based method to recover large-scale structures of SLA fields. Following [24], this suggests considering the following two-scale additive decomposition: X = ¯X + dX + ξ, (11) (11) where ¯X is the large-scale component of the SLA field, typically issued from an optimal interpolation, dX the fine-scale component of the SLA field we aim to reconstruct and ξ is the remaining unresolved scales. The reconstruction of field dX involves a patch-based and EOF-based representation. It consists in regarding field dX as a set of P × P overlapping patches (e.g., 2◦× 2◦), an example of patch locations is shown in Figure 2. This set of patches is referred to as P, and we denote by Ps the patch centered on position s. After building a catalog CP of patches from the available dataset of residual fields X −¯X (see Section 3.2), we proceed to an EOF decomposition of each patch in the catalog. The reconstruction of field dX(Ps, t) at time t is then stated as the analog assimilation of the coefficients of the EOF decomposition in the EOF space given an observation series in the patch space. Formally, dX(Ps, t) decomposes as a linear combination of a number NE of EOF basis functions: dX(Ps, t) = NE ∑ k=1 αk(s, t)EOFk, (12) (12) with EOFk the kth EOF basis and αk(s, t) the corresponding coefficient for patch Ps at time t. Let us denote by Φ(Ps, t) the vector of the NE coefficients αk(s, t): Φ(Ps, t) = {α1(s, t), ..., αNE(s, t)}. This vector represents the projection of dX(Ps, t) in the lower-dimensional EOF space. Figure 2. Two examples of patch locations and their overlapping patch neighbours. Figure 2. Two examples of patch locations and their overlapping patch neighbours. Remote Sens. 2019, 11, 858 8 of 22 4.3. Numerical Resolution Given the proposed analog assimilation model, the proposed scheme first relies on the creation of patch-level catalogs from the training dataset. This step requires the computation of a training dataset of fine scale data dXtraining, this is done by subtracting a large-scale component ¯Xtraining from the original training dataset. Here, we consider the large-scale component of training data to be the result of a global (By global, we mean here an EOF decomposition over the entire case study region, by contrast to the patch-level decomposition considered in the analog assimilation setting.) EOF-based reconstruction using a number of EOF components that retains 95% of the dataset variance, which accounts for horizontal scales up to ≈100 km. This global EOF-based decomposition provides a computationally-efficient means for defining large-scale component ¯X. This EOF-based decomposition step is followed by the extraction of overlapping patches for all variables of interest, namely ¯Xtraining, dXtraining and potential auxiliary variables, and the identification of the EOF basis functions from the resulting raw patch datasets. This leads to the creation of a patch-level catalog CP from the EOF-based representations of each patch. p p Given the patch-level catalog, the algorithm applied for the mapping SLA fields from along-track data, referred to PB-AnDA (for Patch-Based AnDA), is stated in Algorithm 1 and a sketch of the method is shown in Figure 3. 9 of 22 Remote Sens. 2019, 11, 858 Algorithm 1 Patch-Based AnDA 5: the reconstruction of fields X as ¯X + dX. 5: the reconstruction of fields X as ¯X + dX. We may point out two important aspects in the implementation of the proposed patch-level AnDA setting: • (step 3) In the analog forecasting setting, the search for analogs is restricted to patch exemplars in the catalog within a local spatial neighborhood (typically a patch-level 8-neighborhood), except for patches along the seashore for which the search for analogs is restricted to patch exemplars at the same location. • (step 3) In the analog forecasting setting, the search for analogs is restricted to patch exemplars in the catalog within a local spatial neighborhood (typically a patch-level 8-neighborhood), except for patches along the seashore for which the search for analogs is restricted to patch exemplars at the same location. • (step 4) In practice, we do not apply the patch-level assimilation to all grid positions. Consequently, the spatial averaging may result in blocky artifacts. We then apply a patchwise EOF-based decomposition-reconstruction with a smaller patch-size (here, 17 × 17 patches) to remove these blocky artifacts. • (step 4) In practice, we do not apply the patch-level assimilation to all grid positions. Consequently, the spatial averaging may result in blocky artifacts. We then apply a patchwise EOF-based decomposition-reconstruction with a smaller patch-size (here, 17 × 17 patches) to remove these blocky artifacts. 𝑋𝑡𝑟𝑎𝑖𝑛𝑖𝑛𝑔 Creation of patch-based catalogs from training datasets X𝑡𝑟𝑎𝑖𝑛𝑖𝑛𝑔 𝑑𝑋𝑡𝑟𝑎𝑖𝑛𝑖𝑛𝑔 substraction Global EOF reconstruction (95% variance retained) Extracted dataset for each patch position EOF X𝑂𝐼 Simulated along-track data 𝑓𝑖𝑛𝑒𝑠𝑐𝑎𝑙𝑒 𝑜𝑏𝑠𝑒𝑟𝑣𝑎𝑡𝑖𝑜𝑛𝑠 substraction Optimal Interpolation Extracted observations for each patch position Catalog of EOF coefficients 𝑑𝑋 AnDA for each patch + spatial averaging over overlapping patches + postprocessing X 𝑋𝑟𝑒𝑐𝑜𝑛𝑠𝑡 Global EOF projection on the training dataset Figure 3. Sketch of the proposed patch-based Analog Data Assimilation (PB-AnDA). The left block details the construction of the patch-based catalogs from the training dataset. The right block illustrates the process of obtaining the large-scale component of the SLA reconstructed field. The orange dashed rectangle represents the application of the AnDA using the catalog and the fine-scale observations. Finally, the green dashed rectangle shows the final addition operation that yields the reconstructed SLA field. Figure 3. Sketch of the proposed patch-based Analog Data Assimilation (PB-AnDA). The left block details the construction of the patch-based catalogs from the training dataset. The right block illustrates the process of obtaining the large-scale component of the SLA reconstructed field. Algorithm 1 Patch-Based AnDA 1: Compute the large-scale component ¯X, here, we consider the result of optimal interpolation (OI) projected onto the global EOF basis functions. 1: Compute the large-scale component ¯X, here, we consider the result of optimal interpolation (OI) projected onto the global EOF basis functions. 2: Split the case study region into overlapping P × P patches, here, 20 × 20 patches 3: For each patch position s, use the Analog Ensemble Kalman Smoother (AnEnKS) [13], for patch Ps of field dX. As stated in (13), the assimilation is performed in the EOF space, i.e., for EOF decomposition Φ(Ps, t), using the operator derived from EOF-based reconstruction (12) and decomposition (11) as observation model H in (8) and the patch-level training catalog described in the previous section. The assimilation is sequential and is performed each 3-days. 4: Reconstruct fields dX from the set of assimilated patches {dX(Ps, ·)}s. This relies on a spatial averaging over overlapping patches (here, a 5-pixel overlapping in both directions). 4: Reconstruct fields dX from the set of assimilated patches {dX(Ps, ·)}s. This relies on a spatial averaging over overlapping patches (here, a 5-pixel overlapping in both directions). 5. Experimental Setting We detail below the parameter setting of the models evaluated in the reported experiments, including the proposed PB-AnDA scheme: We detail below the parameter setting of the models evaluated in the reported experiments, including the proposed PB-AnDA scheme: • PB-AnDA: We consider 20 × 20 patches with 15-dimensional EOF decompositions (NE = 15), which typically accounts for 99% of the data variance for the considered dataset. The postprocessing step exploits 17 × 17 patches and a 15-dimensional EOF decomposition. Regarding the parametrization of the AnEnKS procedure, we experimentally cross-validated the number of nearest neighbors K to 50, the number of ensemble members nensemble to 100 and the observation covariance error in Equation (8) is considered to be diagonal R = κ2I and κ = 0.001m. • Optimal Interpolation: We apply an Optimal Interpolation to the processed along-track data. It provides the low-resolution component for the proposed PB-AnDA model and a model-driven reference for evaluation purposes. The background field is a null field. We use a Gaussian covariance model with a spatial correlation length of 100 km and a temporal correlation length of 15 days (±5 timesteps since our data is 3-daily). These choices result from a cross-validation experiment. • VE-DINEOF: We apply a second state-of-the-art interpolation scheme using a data-driven strategy solely based on EOF decompositions, namely VE-DINEOF [37]. Using an iterative reconstruction scheme, VE-DINEOF starts by filling the missing data with a first guess, here along-track pseudo-observation field for along-track data positions and ¯X for missing data positions. For each iteration, the resulting field is projected on the most significant EOF components calculated from the clean catalog data, then missing data positions are updated using pixels from the reconstructed new field. We run this iterative process until convergence. To make this algorithm comparable to the proposed PB-AnDA setting, we perform the reconstruction for each patch position then regroup the results as in PB-AnDA. G-AnDA: With a view to evaluating the relevance of the patch-based decomposition, we also apply AnDA at the region scale, referred to as G-AnDA. It relies on an EOF-based decomposition of the detail field dX. We use 150 EOF components, which accounts for more than 99% of the total variance of the SSH dataset. 5: the reconstruction of fields X as ¯X + dX. The orange dashed rectangle represents the application of the AnDA using the catalog and the fine-scale observations. Finally, the green dashed rectangle shows the final addition operation that yields the reconstructed SLA field. 10 of 22 10 of 22 Remote Sens. 2019, 11, 858 5. Experimental Setting From cross-validation experiments, the associated AnEnKS procedure relies on a locally-linear analog forecasting model with K = 500 analogs, nensemble = 100 ensemble members and a diagonal observation covariance similar to as in PB-AnDA. The patch-based experiments were run on Teralab infrastructure using a multi-core virtual machine (30 CPUs, 64G of RAM). We used the Python toolbox for patch-based analog data assimilation [24] (available at github.com/rfablet/PB_ANDA). Optimal Interpolation was implemented on Matlab using [36]. Throughout the experiments, two metrics are used to assess the performance of the considered interpolation methods: (i) Daily and mean Root Mean Square Error (RMSE) series between the reconstructed SLA fields X and the groundtruthed ones; (ii) daily and mean correlation coefficient between the fine-scale component dX of the reconstructed SLA fields and of the groundtruthed ones. These two metrics allow a good evaluation on image reconstruction capabilities and are widely used in missing data interpolation literature [38,39]. 6. Results We evaluate the proposed PB-AnDA approach using the OSSE presented in Section 2. We perform a qualitative and quantitative comparison to state-of-the-art approaches. We first describe the parameter setting used for the PB-AnDA as well as benchmarked models, namely OI, an EOF-based approach [37] and a direct application of AnDA at the region level. We then report numerical experiments for noise-free and noisy observation data as well the relevance of auxiliary variables in the proposed PB-AnDA scheme. Remote Sens. 2019, 11, 858 11 of 22 11 of 22 6.1. SLA Reconstruction from Noise-Free Along-Track Data 6.1. SLA Reconstruction from Noise-Free Along-Track Data We first performed an idealized noise-free experiment, where the along-track observations were not contaminated with noise. The interpolation performances for this experiment are illustrated in Table 1. Our PB-AnDA algorithm significantly outperforms OI. More specifically, the locally-linear PB-AnDA results in the best reconstruction among the competing methods. We suggest that this improvement comes from the reconstruction of fine-scale features learned from the archived model simulation data. Figure 4a reports interpolated SSH fields and their gradient fields which further confirm our intuition. PB-AnDA interpolation shows an enhancement of the gradients and comes out with some fine-scale eddies that were smoothed out in OI and VE-DINEOF. This is also confirmed by the Fourier power spectrum of the interpolated SLA fields in Figure 4b. Table 1. SLA Interpolation performance for a noise-free experiment: Root Mean Square Error (RMSE) (meters), correlation statistics for Optimal Interpolation (OI), VE-DINEOF, G-AnDA and PB-AnDA with regard to the groundtruthed SLA fields. The relative gain with regard to OI is also shown in percentage. See Section 5 for the corresponding parameter settings. Criterion RMSE Correlation RMSEOI−RMSE RMSEOI OI 0.026 ± 0.007 0.81 ± 0.08 - VE-DINEOF 0.023 ± 0.007 0.85 ± 0.07 11.53% G-AnDA 0.020 ± 0.006 0.89 ± 0.04 23.07% PB-AnDA Locally-constant 0.014 ± 0.005 0.95 ± 0.03 46.15% Locally-Increment 0.014 ± 0.005 0.95 ± 0.03 46.15% Locally-Linear 0.013 ± 0.005 0.96 ± 0.02 50.00% (a) Figure 4. Cont. Table 1. SLA Interpolation performance for a noise-free experiment: Root Mean Square Error (RMSE) (meters), correlation statistics for Optimal Interpolation (OI), VE-DINEOF, G-AnDA and PB-AnDA with regard to the groundtruthed SLA fields. The relative gain with regard to OI is also shown in percentage. See Section 5 for the corresponding parameter settings. Table 1. SLA Interpolation performance for a noise-free experiment: Root Mean Square Error (RMSE) (meters), correlation statistics for Optimal Interpolation (OI), VE-DINEOF, G-AnDA and PB-AnDA with regard to the groundtruthed SLA fields. The relative gain with regard to OI is also shown in percentage. See Section 5 for the corresponding parameter settings. Criterion RMSE Correlation RMSEOI−RMSE RMSEOI OI 0.026 ± 0.007 0.81 ± 0.08 - VE-DINEOF 0.023 ± 0.007 0.85 ± 0.07 11.53% G-AnDA 0.020 ± 0.006 0.89 ± 0.04 23.07% PB-AnDA Locally-constant 0.014 ± 0.005 0.95 ± 0.03 46.15% Locally-Increment 0.014 ± 0.005 0.95 ± 0.03 46.15% Locally-Linear 0.013 ± 0.005 0.96 ± 0.02 50.00% (a) Figure 4. Cont. 6.2. SLA Reconstruction from Noisy Along-Track Data We also evaluated the proposed approach for noisy along-track data. Here, we ran two experiments with an additive zero-mean Gaussian noise applied to the simulated along-track data. We considered a diagonal noise covariance of γ2I where γ = 0.01 m (Experiment A) and γ = 0.03 m (Experiment B) which was more close to the instrumental error of conventional altimeters. Given the resulting noisy along-track dataset, we applied the same methods as for the noise-free case study. We ran PB-AnDA using different values for κ. For Experiment A, Table 2 shows that the minimum is reached using the true value of the error κ = 0.01 m. While for Experiment B, Table 3 shows that the minimum is counter-intuitively reached again using value of the error κ = 0.01 m with a negligible margin compared to the true value. Table 2. Impact of standard variation of observation error κ in AnDA interpolation performance using noisy along-track data (γ = 0.01 m): RMSE (meters) of AnDA interpolation for different values of parameter κ. For the same dataset, OI RMSE is 0.039. Table 2. Impact of standard variation of observation error κ in AnDA interpolation performance using noisy along-track data (γ = 0.01 m): RMSE (meters) of AnDA interpolation for different values of parameter κ. For the same dataset, OI RMSE is 0.039. κ 0.1 0.05 0.03 0.01 0.005 0.001 0.0001 rmsePB−AnDA 0.035 0.030 0.028 0.025 0.025 0.029 0.044 Table 3. Impact of standard variation of observation error κ in AnDA interpolation performance using noisy along-track data (γ = 0.03 m): RMSE (meters) of AnDA interpolation for different values of parameter κ. For the same dataset, OI RMSE is 0.066. Table 3. Impact of standard variation of observation error κ in AnDA interpolation performance using noisy along-track data (γ = 0.03 m): RMSE (meters) of AnDA interpolation for different values of parameter κ. For the same dataset, OI RMSE is 0.066. Table 3. Impact of standard variation of observation error κ in AnDA interpolation performance using noisy along-track data (γ = 0.03 m): RMSE (meters) of AnDA interpolation for different values of parameter κ. For the same dataset, OI RMSE is 0.066. κ 0.1 0.05 0.03 0.01 0.005 0.001 0.0001 rmsePB−AnDA 0.038 0.036 0.035 0.0349 0.037 0.046 0.076 Our algorithm is then compared with the results of the application of the competing algorithms considered in this work. 6.1. SLA Reconstruction from Noise-Free Along-Track Data (a) Figure 4. Cont. (a) Figure 4. Cont. 12 of 22 Remote Sens. 2019, 11, 858 (b) Figure 4. Reconstructed SLA fields (meters) using noise-free along-track observation using OI, VE-DINEOF, G-AnDA, PB-AnDA on the 54th day (24 February 2012): From left to right, the first row shows the ground truth field, the simulated available along-tracks for that day, the ground truth gradient field. The second and third rows show each of the reconstruction and their corresponding gradient fields, from left to right, OI, VE-DINEOF, G-ANDA and PB-AnDA. The Fourier power spectrum of the competing methods is also included. (b) (b) Figure 4. Reconstructed SLA fields (meters) using noise-free along-track observation using OI, VE-DINEOF, G-AnDA, PB-AnDA on the 54th day (24 February 2012): From left to right, the first row shows the ground truth field, the simulated available along-tracks for that day, the ground truth gradient field. The second and third rows show each of the reconstruction and their corresponding gradient fields, from left to right, OI, VE-DINEOF, G-ANDA and PB-AnDA. The Fourier power spectrum of the competing methods is also included. 6.2. SLA Reconstruction from Noisy Along-Track Data Results are shown in Table 4. PB-AnDA still outperforms OI in terms of RMSE and correlation statistics in both experiments. The locally-linear version of PB-AnDA depicts the best reconstruction performance. We report an example of the reconstruction in Figure 5. Similarly to the noise-free case study, PB-AnDA better recovers finer-scale structures in Figure 5a compared with OI, emote Sens. 2019, 11, 858 13 E-DINEOF and G-AnDA. In Figure 5b, PB-AnDA also better reconstructs a larger-scale North-E tructure, poorly sampled by along-track data and hence poorly interpolated by OI. Table 4. SLA Interpolation performance for noisy along-track data: RMSE (meters) and correlation statistics for OI, VE-DINEOF, G-AnDA and PB-AnDA w.r.t. the groundtruthed SLA fields. The relative gain with regard to OI is also shown in percentage. See Section 5 for the corresponding parameter settings. Criterion RMSE Correlation RMSEOI−RMSE RMSEOI γ = 0.01 m OI 0.039 ± 0.005 0.64 ± 0.09 - VE-DINEOF 0.035 ± 0.005 0.68 ± 0.09 10.25% G-AnDA 0.030 ± 0.005 0.78 ± 0.06 23.07% PB-AnDA Locally constant 0.026 ± 0.005 0.82 ± 0.05 33.33% Increment 0.028 ± 0.005 0.81 ± 0.05 28.20% Local Linear 0.0245 ± 0.005 0.83 ± 0.05 37.17% γ = 0.03 m OI 0.066 ± 0.006 0.41 ± 0.09 - VE-DINEOF 0.060 ± 0.006 0.45 ± 0.09 9.09% G-AnDA 0.039 ± 0.006 0.67 ± 0.09 40.90% PB-AnDA Locally constant 0.035 ± 0.006 0.688 ± 0.064 46.96% Increment 0.036 ± 0.006 0.656 ± 0.07 45.45% Local Linear 0.032 ± 0.006 0.708 ± 0.063 51.51% (a) Figure 5. Cont. 13 of 22 Remote Sens. 2019, 11, 858 VE-DINEOF and G-AnDA. In Figure 5b, PB-AnDA also better reconstructs a larger-scale North-East structure, poorly sampled by along-track data and hence poorly interpolated by OI. Table 4. SLA Interpolation performance for noisy along-track data: RMSE (meters) and correlation statistics for OI, VE-DINEOF, G-AnDA and PB-AnDA w.r.t. the groundtruthed SLA fields. The relative gain with regard to OI is also shown in percentage. See Section 5 for the corresponding parameter settings. Table 4. SLA Interpolation performance for noisy along-track data: RMSE (meters) and correlation statistics for OI, VE-DINEOF, G-AnDA and PB-AnDA w.r.t. the groundtruthed SLA fields. The relative gain with regard to OI is also shown in percentage. See Section 5 for the corresponding parameter settings. Table 4. SLA Interpolation performance for noisy along-track data: RMSE (meters) and correlation statistics for OI, VE-DINEOF, G-AnDA and PB-AnDA w.r.t. the groundtruthed SLA fields. 6.2. SLA Reconstruction from Noisy Along-Track Data The relative gain with regard to OI is also shown in percentage. See Section 5 for the corresponding parameter settings. , , g The relative gain with regard to OI is also shown in percentage. See Section 5 for the corresponding parameter settings. Criterion RMSE Correlation RMSEOI−RMSE RMSEOI γ = 0.01 m OI 0.039 ± 0.005 0.64 ± 0.09 - VE-DINEOF 0.035 ± 0.005 0.68 ± 0.09 10.25% G-AnDA 0.030 ± 0.005 0.78 ± 0.06 23.07% PB-AnDA Locally constant 0.026 ± 0.005 0.82 ± 0.05 33.33% Increment 0.028 ± 0.005 0.81 ± 0.05 28.20% Local Linear 0.0245 ± 0.005 0.83 ± 0.05 37.17% γ = 0.03 m OI 0.066 ± 0.006 0.41 ± 0.09 - VE-DINEOF 0.060 ± 0.006 0.45 ± 0.09 9.09% G-AnDA 0.039 ± 0.006 0.67 ± 0.09 40.90% PB-AnDA Locally constant 0.035 ± 0.006 0.688 ± 0.064 46.96% Increment 0.036 ± 0.006 0.656 ± 0.07 45.45% Local Linear 0.032 ± 0.006 0.708 ± 0.063 51.51% (a) Figure 5. Cont. Criterion RMSE Correlation RMSEOI−RMSE RMSEOI γ = 0.01 m OI 0.039 ± 0.005 0.64 ± 0.09 - VE-DINEOF 0.035 ± 0.005 0.68 ± 0.09 10.25% G-AnDA 0.030 ± 0.005 0.78 ± 0.06 23.07% PB-AnDA Locally constant 0.026 ± 0.005 0.82 ± 0.05 33.33% Increment 0.028 ± 0.005 0.81 ± 0.05 28.20% Local Linear 0.0245 ± 0.005 0.83 ± 0.05 37.17% γ = 0.03 m OI 0.066 ± 0.006 0.41 ± 0.09 - VE-DINEOF 0.060 ± 0.006 0.45 ± 0.09 9.09% G-AnDA 0.039 ± 0.006 0.67 ± 0.09 40.90% PB-AnDA Locally constant 0.035 ± 0.006 0.688 ± 0.064 46.96% Increment 0.036 ± 0.006 0.656 ± 0.07 45.45% Local Linear 0.032 ± 0.006 0.708 ± 0.063 51.51% (a) Figure 5. Cont. (a) Figure 5. Cont. Figure 5. Cont. 14 of 22 Remote Sens. 2019, 11, 858 (b) Figure 5. Reconstruction of SLA fields (meters) from noisy along-track data using OI, VE-DINEOF, G-AnDA & PB-AnDA on day 225th (a) & 228th (b). b) ( (b) Figure 5. Reconstruction of SLA fields (meters) from noisy along-track data using OI, VE-DINEOF, G-AnDA & PB-AnDA on day 225th (a) & 228th (b). 6.3. PB-AnDA Models with Auxiliary Variables 6.3. PB-AnDA Models with Auxiliary Variables We further explore the flexibility of the analog setting to the use of additional geophysical variable information as explained in Section 4.2. Intuitively, we expect SLA fields to involve inter-scale dependencies as well as synergies with other tracers [19,40]. The use of auxiliary variables provide the means for evaluating such dependencies and their potential impact on reconstruction performance. We consider two auxiliary variables that are used in the locally-linear analog forecasting model (7): (i) To account for the relationship between the large-scale and fine-scale component, we may consider variable ¯X; (ii) considering potential SST-SSH synergies, we consider SST fields. Overall, we consider four parameterization of the regression variables used in PB-AnDA: The sole use of dX (PB-AnDA-dX), the joint use of dX and SST fields (PB-AnDA-dX+SST), the joint use of dX and ¯X (PB-AnDA-dX+ ¯X), the joint use of dX and the groudntruthed version of ¯X denoted by ¯XGT, (PB-AnDA-dX+ ¯XGT). The later provides a lower-bound for the reconstruction performance, assuming the low-resolution component is perfectly estimated. We report mean RMSE (meters) and correlation statistics for these four PB-AnDA parameterizations in Table 5 for the noisy case-study. Considering PB-AnDA-dX as reference, these results show a very slight improvement when complementing dX with SST information. Though limited, we report a greater improvement when adding the low-resolution component ¯X. Interestingly, a significantly greater improvement is obtained when adding the true low-resolution information. The mean results are in accordance with [17], which reported that large-scale SLA information was more informative than SST to improve the reconstruction of the SLA at finer scales. Though mean statistics over one year leads to rather limited improvement, daily RMSE time series (Figure 6) reveal that for some periods, for instance between day 130 and 150, relative improvements in terms of RMSE may reach 10% with the additional information brought by the large-scale component. In this respect, it may noted 15 of 22 Remote Sens. 2019, 11, 858 that PB-AnDA-dX+ ¯X always perform better than PB-AnDA-dX. An example of the reconstruction in reported in Figure 7. Table 5. PB-AnDA reconstruction performance using noisy along-track data for different choices of the regression variables in the locally-linear analog forecasting model: PB-AnDA-dX using solely dX, PB-AnDA-dX+ SST (Sea Surface Temperature) using both dX and SST, PB-AnDA-dX + ¯X using both dX and ¯X, and PB-AnDA-dX + ¯XGT using dX and the true large-scale component ¯XGT. 6.3. PB-AnDA Models with Auxiliary Variables The table shows the RMSE (meters) and correlation statistics. PB-AnDA Model RMSE Correlation γ = 0.01 m PB-AnDA-dX 0.025 ± 0.005 0.83 ± 0.05 PB-AnDA-dX + SST 0.024 ± 0.005 0.83 ± 0.05 PB-AnDA-dX + ¯X 0.023 ± 0.005 0.84 ± 0.05 PB-AnDA-dX + ¯XGT 0.021 ± 0.004 0.87 ± 0.04 γ = 0.03 m PB-AnDA-dX 0.032 ± 0.006 0.708 ± 0.06 PB-AnDA-dX + SST 0.031 ± 0.006 0.710 ± 0.06 PB-AnDA-dX + ¯X 0.029 ± 0.006 0.717 ± 0.06 PB-AnDA-dX + ¯XGT 0.026 ± 0.005 0.730 ± 0.05 Figure 6. Daily RMSE (meters) time series of PB-AnDA SLA reconstructions using noisy along-track data for different choices of the regression variables in the locally-linear analog forecasting model: PB-AnDA-dX (light blue), PB-AnDA-dX+ SST (orange) and PB-AnDA-dX + ¯X (green). PB-AnDA Model RMSE Correlation γ = 0.01 m PB-AnDA-dX 0.025 ± 0.005 0.83 ± 0.05 PB-AnDA-dX + SST 0.024 ± 0.005 0.83 ± 0.05 PB-AnDA-dX + ¯X 0.023 ± 0.005 0.84 ± 0.05 PB-AnDA-dX + ¯XGT 0.021 ± 0.004 0.87 ± 0.04 γ = 0.03 m PB-AnDA-dX 0.032 ± 0.006 0.708 ± 0.06 PB-AnDA-dX + SST 0.031 ± 0.006 0.710 ± 0.06 PB-AnDA-dX + ¯X 0.029 ± 0.006 0.717 ± 0.06 PB-AnDA-dX + ¯XGT 0.026 ± 0.005 0.730 ± 0.05 Figure 6. Daily RMSE (meters) time series of PB-AnDA SLA reconstructions using noisy along-track data for different choices of the regression variables in the locally-linear analog forecasting model: PB-AnDA-dX (light blue), PB-AnDA-dX+ SST (orange) and PB-AnDA-dX + ¯X (green). Figure 6. Daily RMSE (meters) time series of PB-AnDA SLA reconstructions using noisy along-tra data for different choices of the regression variables in the locally-linear analog forecasting mod Figure 6. Daily RMSE (meters) time series of PB-AnDA SLA reconstructions using noisy along-track data for different choices of the regression variables in the locally-linear analog forecasting model: PB-AnDA-dX (light blue), PB-AnDA-dX+ SST (orange) and PB-AnDA-dX + ¯X (green). 16 of 22 Remote Sens. 2019, 11, 858 (a) (b) Figure 7. (Noisy observation) Reconstruction of SLA fields (meters) using PB-AnDA with different multivariate regression models on day 57th (a) & 237th (b). ( ) (a) (a) (a) (b) Figure 7. (Noisy observation) Reconstruction of SLA fields (meters) using PB-AnDA with different multivariate regression models on day 57th (a) & 237th (b). (a (b) (b) Figure 7. 7. Discussion Analog data assimilation can be regarded as a means to fuse ocean models and satellite-derived data. We regard this study as a proof-of-concept, which opens research avenues as well as new directions for operational oceanography. Our results advocate for complementary experiments at the global scale or in different ocean regions for a variety of dynamical situations with a view to further evaluating the relevance of the proposed analog assimilation framework. Such experiments should evaluate the sensitivity of the assimilation with respect to the size of the catalog. The scaling up to the global ocean also suggests investigating computationally-efficient implementation of the analog data assimilation. In this respect, the proposed patch-based framework intrinsically ensures high parallelization performance. From a methodological point of view, a relative weakness of the analog forecasting models (9) may be their low physical interpretation compared with physically-derived priors [18]. The combination of such physically-derived parameterizations to data-driven strategies appear to be a promising research direction. While we considered an OSSE to evaluate the proposed scheme, future work will investigate applications to real satellite-derived datasets, including the use of independent observation data such as surface drifters’ track data to further assess the performance of the proposed algorithm. The analog method is at the heart of this work as it is appealing by its implementation ease and its intuitive strategy, but it must not be seen as the only data-driven method adapted to the framework we presented. As long as a data-driven forecasting operator can be derived, other data-driven methods can be investigated [41,42]. One promising path is the use of neural networks, as they sparked off a series of breakthroughs in other fields [42–46]. While neural network based approaches can lead to better performances due to their superior regressing capabilities, two clear advantages of adopting analog methods are the fact that they do not need a time consuming training phase and that analog methods are easy to understand and interpret compared to black-box approaches such as neural networks. The Analog Data Assimilation method as used in this work relies on several hyperparameters, assumptions and design choices. These considerations are discussed in the following: The Analog Data Assimilation method as used in this work relies on several hyperparameters, assumptions and design choices. 6.3. PB-AnDA Models with Auxiliary Variables (Noisy observation) Reconstruction of SLA fields (meters) using PB-AnDA with different multivariate regression models on day 57th (a) & 237th (b). Remote Sens. 2019, 11, 858 17 of 22 17 of 22 8. Materials and Methods The experimental results presented in this work were obtained using the Python PB-AnDA toolbox made available by the authors at https://github.com/rfablet/PB_ANDA. 7. Discussion • We encourage the reader to refer to the discussion section in [24] for more insights about the rationale behind the use of patch-based representations and EOF-based dimensionality reduction. Through the experiments conducted in this work, it was shown that the best performance was always reached using the locally-linear analog operator, which is in line with our previous findings [13,24]. An explanation for the superiority of this approach is that it better approximates locally the true dynamical model [48]. Beyond along-track altimeter data as considered in this study, future missions such as SWOT (NASA/CNES) promise an unprecedented coverage around the globe. More specifically, the large swath is expected to provide a large number of data, urging for the inspection of the potential improvements that this new mission will bring compared to classical along-track data. In the context of analog data assimilation, the interest of SWOT data may be two-fold. First, regarding observation model (8), SWOT mission will both significantly increase the number of available observation data and enable the definition of more complex observation models exploiting for instance velocity-based or vorticity-based criterion. Second, SWOT data might also be used to build representative patch-level catalogs of exemplars. Future work should investigate these two directions using simulated SWOT test-beds [49]. 7. Discussion These considerations are discussed in the following: • In this work, we used all the available data for the creation of the catalog, we expect that a rich dataset is important in increasing the likelihood of finding good analogs, yet a more thorough study is needed to assess the impact of reducing the temporal resolution of the dataset versus reducing the amount of the total available data. To compensate the computational impact of using a large dataset for the search for analogs, we used the FLANN (Fast Library for Approximate Nearest Neighbors) library as in [26]. This method makes use of tree-indexing techniques and is suitable for this kind of high dimensional applications [47]. • While we used a conditional Gaussian distribution in Equation (9), another alternative is the use of a conditional multinomial distribution. This resorts to sampling one of the analogs’ successors as the forecast. Adopting this alternative would mean that we rely strongly on the archived catalog, so that forecasts of each ensemble member are actual elements of the catalog. This reduces the ability of the model to generate a rich variability of forecast scenes as done by the conditional Gaussian distribution. • While we used a Gaussian kernel in Equation (10), other alternatives include cone kernels [10] which are more adapted to finding analogs in time series. The performance of our algorithm was slightly improved at the expense of more time execution and an additional hyperparameter to tune empirically, and we decided to prioritize simpler and efficient kernels. Regarding the scale parameter, the median was chosen due to its robustness to outliers. • Although the AnEnKS was used in this work, a possible alternative is the use of an analog based Particle Smoother which drops Gaussian assumptions, however techniques based on particle filters need more ensemble members than their Ensemble Kalman Filter counterparts, thus causing a considerable increase in computational demands which was impractical for our application. Remote Sens. 2019, 11, 858 18 of 22 • We encourage the reader to refer to the discussion section in [24] for more insights about the rationale behind the use of patch-based representations and EOF-based dimensionality reduction. • We encourage the reader to refer to the discussion section in [24] for more insights about the rationale behind the use of patch-based representations and EOF-based dimensionality reduction. 9. Conclusions This work sheds light on the opportunities that data science methods are offering to improve altimetry in the era of big data. Assuming the availability of high-resolution numerical simulations, we show that Analog Data Assimilation (AnDA) can outperform the Optimal Interpolation method and retrieve smoothed out structures resulting from the sole use of OI both with idealized noise-free and more realistic noisy observations for the considered case study. Importantly, the reported experiments point out the relevance for combining OI for larger scales (above 100 km) whereas the proposed patch-based analog setting successfully applies to the finer-scale range below 100 km. This is in agreement with the recent application of the analog data assimilation to the reconstruction of cloud-free SST fields [24]. We also demonstrate that AnDA can embed complementary variables in a simple manner through the regression variables used in the locally-linear analog forecasting operator. In agreement with our recent analysis [17], we demonstrate that the additional use of large-scale SLA information may further improve the reconstruction performance for fine-scale structures. We may state here the limitations of the present work and possible research avenues for the future. The experiments presented in this work were conducted on a numerical simulation derived dataset. A major future work direction would be then to apply the same procedure on real satellite-derived SLA contaminated with more complex noise models, then investigate the contribution of the use of numerical simulation datasets as catalogs. As combining multi-source datsets can also be challenging when using auxiliary variables relationships with SLA, an interesting experiment for example would be constructing a catalog with real SST observations combined with numerical simulation SLA datasets. More efforts should be directed to assess the quality of the catalogs (spatio-temporal resolution, total years of measurements to consider, occurence of rare events, etc.). Besides, building a good catalog can represent an opportunity for the use of neural networks based methods, and confronting these powerful regressors to our method is a promising future step. We also note that PB-AnDA can be a relevant candidate for the interpolation of other geophysical variables (e.g., Sea Surface Salinity, Chlorophyll concentrations, etc.) under the condition that they verify the set of assumptions made in this work. 19 of 22 19 of 22 Remote Sens. 2019, 11, 858 Author Contributions: R.L., R.F. and G.C. conceived and designed the experiments; R.L. and M.S. created the datasets; R.L. and P.H.V. 9. Conclusions performed the experiments; R.L. and M.S. analyzed the data; T.F., B.C. contributed materials/analysis tools; R.L. and R.F. wrote the paper. Funding: Redouane Lguensat is funded through a CNES (French Space Agency) postdoctoral grant. This work is also supported by ANR (Agence Nationale de la Recherche, grant ANR-13-MONU-0014), Labex Cominlabs (grant SEACS) and TeraLab (grant TIAMSEA). Conflicts of Interest: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results. References 1. Zhang, L.; Zhang, L.; Du, B. Deep learning for remote sensing data: A technical tutorial on the state of the art. IEEE Geosci. Remote Sens. Mag. 2016, 4, 22–40. [CrossRef] 1. Zhang, L.; Zhang, L.; Du, B. Deep learning for remote sensing data: A technical tutorial on the state of the art. IEEE Geosci. Remote Sens. Mag. 2016, 4, 22–40. [CrossRef] 2. Lary, D.J.; Alavi, A.H.; Gandomi, A.H.; Walker, A.L. Machine learning in geosciences and remote sensing. Geosci. Front. 2016, 7, 3–10. [CrossRef] 3. Lorenz, E.N. Atmospheric predictability as revealed by naturally occurring analogues. J. Atmos. Sci. 1969, 26, 636–646. [CrossRef] 3. Lorenz, E.N. Atmospheric predictability as revealed by naturally occurring analogues. J. Atmos. Sci. 1969, 26, 636–646. [CrossRef] 4. McDermott, P.L.; Wikle, C.K. A model-based approach for analog spatio-temporal dynamic forecasting. Environmetrics 2015. [CrossRef] 4. McDermott, P.L.; Wikle, C.K. A model-based approach for analog spatio-temporal dynamic forecasting. Environmetrics 2015. [CrossRef] 5. Comeau, D.; Giannakis, D.; Zhao, Z.; Majda, A.J. Predicting regional and pan-Arctic sea ice anomalies with kernel analog forecasting. arXiv 2017, arXiv:1705.05228. 5. Comeau, D.; Giannakis, D.; Zhao, Z.; Majda, A.J. Predicting regional and pan-Arctic sea ice anomalies with kernel analog forecasting. arXiv 2017, arXiv:1705.05228. 6. Atencia, A.; Zawadzki, I. A Comparison of Two Techniques for Generating Nowcasting Ensembles Analogs Selection and Comparison of Techniques. Mon. Weather Rev. 2015, 143, 2890–2908. [CrossR 7. Delle Monache, L.; Eckel, F.A.; Rife, D.L.; Nagarajan, B.; Searight, K. Probabilistic weather prediction w an analog ensemble. Mon. Weather Rev. 2013, 141, 3498–3516. [CrossRef] 8. Yiou, P. AnaWEGE: A weather generator based on analogues of atmospheric circulation. Geosci. Model Dev. 2014, 7, 531–543. [CrossRef] 8. Yiou, P. AnaWEGE: A weather generator based on analogues of atmospheric circulation. Geosci. Model Dev. 2014, 7, 531–543. [CrossRef] 9. Hamill, T.M.; Whitaker, J.S. Probabilistic quantitative precipitation forecasts based on reforecast analogs: Theory and application. Mon. Weather Rev. 2006, 134, 3209–3229. [CrossRef] 10. Zhao, Z.; Giannakis, D. Analog Forecasting with Dynamics-Adapted Kernels. arXiv 2014. arXiv: 1412.3831. 11. Horton, P.; Jaboyedoff, M.; Obled, C. Global Optimization of an Analog Method by Means of Genetic Algorithms. Mon. Weather Rev. 2017, 145, 1275–1294. [CrossRef] 12. Tandeo, P.; Ailliot, P.; Chapron, B.; Lguensat, R.; Fablet, R. The analog data assimilation: Application to 20 years of altimetric data. In Proceedings of the CI 2015: 5th International Workshop on Climate Informatics, Boulder, CO, USA, 24–25 September 2015; pp. 1–2. 13. Locally-Linear Operator Fitting a weighted least square between the K analogs and their successors we obtain slope α(x(t −1)) and intercept β(x(t −1)) parameters, and residuals ξk(x(t −1)) that lead us to µ and Σ: ξk(x(t −1)) = Sk(x(t −1)) −(α(x(t −1))Ak(x(t −1) + β(x(t −1))) µ = α(x(t −1)).x(t −1) + β(x(t −1)) ξk(x(t −1)) = Sk(x(t −1)) −(α(x(t −1))Ak(x(t −1) + β(x(t −1))) µ = α(x(t −1)).x(t −1) + β(x(t −1)) µ ( ( )) ( ) β( Σ = cov((ξk(x(t −1)))k∈1,K) Σ = cov((ξk(x(t −1)))k∈1,K) Locally-Incremental Operator Locally-Incremental Operator τk(x(t −1)) = Sk(x(t −1)) −Ak(x(t −1)) µ = x(t −1) + ∑K k=1 KG(x(t −1), Ak)τk(x(t −1)) Σ = covKG(x(t −1) + τk(x(t −1))k∈1,K) k(x(t −1)) = Sk(x(t −1)) −Ak(x(t −1)) Locally-Linear Operator Abbreviations The following abbreviations are used in this manuscript: AVISO+ Archivage, Validation et Interprétation des données des Satellites Océanographiques CMEMS Copernicus Marine Environment Monitoring Service OSSE Observation System Simulation Experiment OGCM Ocean General Circulation Model OFES OGCM for the Earth Simulation Appendix A. Analog Forecasting Operators In this appendix, we present the calculations needed for the three analog forecasting operators used in this work. An illustration is also given in Figure A1. Following [13], we give for each operator, the equations for µ and Σ given A the analogs of x(t −1), their successors S and the corresponding weights KG: Figure A1. Illustration of the three analog forecasting operator. Figure A1. Illustration of the three analog forecasting operator. ocally-Constant Operator µ = ∑K k=1 KG(x(t −1), Ak)Sk(x(t −1)) Σ = covKG(Sk(x(t −1)))k∈1,K) where covKG is a weighted covariance. Locally-Constant Operator µ = ∑K k=1 KG(x(t −1), Ak)Sk(x(t −1)) Σ = covKG(Sk(x(t −1)))k∈1,K) where covKG is a weighted covariance. 20 of 22 Remote Sens. 2019, 11, 858 References [CrossRef] 23. Turiel, A.; Nieves, V.; Garcia-Ladona, E.; Font, J.; Rio, M.H.; Larnicol, G. The multifractal structure of satellite sea surface temperature maps can be used to obtain global maps of streamlines. Ocean Sci. 2009, 5, 447–460. [CrossRef] 24. Fablet, R.; Viet, P.H.; Lguensat, R. Data-driven Models for the Spatio-Temporal Interpolation of satellite-derived SST Fields. IEEE Trans. Comput. Imaging 2017. [CrossRef] 25. Buades, A.; Coll, B.; Morel, J.M. A non-local algorithm for image denoising. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, CVPR’05, San Diego, CA, USA, 20–25 June 2005; Volume 2, pp. 60–65. [CrossRef] 26. Fablet, R.; Huynh Viet, P.; Lguensat, R.; Horrein, P.H.; Chapron, B. Spatio-Temporal Interpolation of Cloudy SST Fields Using Conditional Analog Data Assimilation. Remote Sens. 2018, 10, 310. [CrossRef] 27. Masumoto, Y.; Sasaki, H.; Kagimoto, T.; Komori, N.; Ishida, A.; Sasai, Y.; Miyama, T.; Motoi, T.; Mitsudera, H.; Takahashi, K.; et al. A fifty-year eddy-resolving simulation of the world ocean: Preliminary outcomes of OFES (OGCM for the Earth Simulator). J. Earth Simul. 2004, 1, 35–56. 28. Sasaki, H.; Nonaka, M.; Masumoto, Y.; Sasai, Y.; Uehara, H.; Sakuma, H. An eddy-resolving hindcast simulation of the quasi-global ocean from 1950 to 2003 on the Earth Simulator. In High Resolution Numerical Modelling of the Atmosphere and Ocean; Springer: Berlin/Heidelberg, Germany, 2008. 29. Shaw, P.T.; Chao, S.Y.; Fu, L.L. Sea surface height variations in the South China Sea from satellite al Oceanol. Acta 1999, 22, 1–17. [CrossRef] 30. Bocquet, M.; Pires, C.A.; Wu, L. Beyond Gaussian statistical modeling in geophysical data assim Mon. Weather Rev. 2010, 138, 2997–3023. [CrossRef] 31. Ide, K.; Courtier, P.; Ghil, M.; Lorenc, A. Unified notation for data assimilation: operational, sequential and variational. Practice 1997, 75, 181–189. 32. Asch, M.; Bocquet, M.; Nodet, M. Data Assimilation: Methods, Algorithms, and Applications; Fundamentals of Algorithms; SIAM: Philadelphia, PA, USA, 2016. 33. De Mey, P.; Robinson, A.R. Assimilation of altimeter eddy fields in a limited-area quasi-geostrophic model. J. Phys. Oceanogr. 1987, 17, 2280–2293. [CrossRef] 34. Gandin, L. Objective analysis of meteorological fields. By L. S. Gandin. Translated from the Russian. Jerusalem (Israel Program for Scientific Translations), 1965. Pp. vi, 242: 53 Figures; 28 Tables. £4 1s. 0d. Q. J. R. Meteorol. Soc. 1966, 92, 447. [CrossRef] Lorenc, A.C. Analysis methods for numerical weather prediction. Q. J. R. Meteorol. Soc. 1986, 112, 1177–1194 [CrossRef] 36. Escudier, R.; Bouffard, J.; Pascual, A.; Poulain, P.M.; Pujol, M.I. References Lguensat, R.; Tandeo, P.; Ailliot, P.; Pulido, M.; Fablet, R. The Analog Data Assimilation. Mon. Weather Rev. 2017, 145, 4093–4107. [CrossRef] 14. Hardman-Mountford, N.; Richardson, A.; Boyer, D.; Kreiner, A.; Boyer, H. Relating sardine recruitment in the Northern Benguela to satellite-derived sea surface height using a neural network pattern recognition approach. In Progress in Oceanography: ENVIFISH: Investigating Environmental Causes of Pelagic Fisheries Variability in the SE Atlantic; Elsevier Ltd.: Amsterdam, The Netherlands, 2003; Volume 59, pp. 241–255. 15. Le Traon, P.; Nadal, F.; Ducet, N. An improved mapping method of multisatellite altimeter data. J. Atmos. Ocean. Technol. 1998, 15, 522–534. [CrossRef] 16. Bretherton, F.P.; Davis, R.E.; Fandry, C. A technique for objective analysis and design of oceanographic experiments applied to MODE-73. In Deep Sea Research and Oceanographic Abstracts; Elsevier: Amsterdam, The Netherlands, 1976; Volume 23, pp. 559–582. 17. Fablet, R.; Verron, J.; Mourre, B.; Chapron, B.; Pascual, A. Improving mesoscale altimetric data from a multi-tracer convolutional processing of standard satellite-derived products. IEEE Trans. Geosci. Remote Sens. 2018, 56, 2518–2525. [CrossRef] 21 of 22 Remote Sens. 2019, 11, 858 21 of 22 18. Ubelmann, C.; Klein, P.; Fu, L.L. Dynamic Interpolation of Sea Surface Height and Potential Applications for Future High-Resolution Altimetry Mapping. J. Atmos. Ocean. Technol. 2014, 32, 177–184. [CrossRef] 19. Klein, P.; Isern-Fontanet, J.; Lapeyre, G.; Roullet, G.; Danioux, E.; Chapron, B.; Le Gentil, S.; Sasaki, H. Diagnosis of vertical velocities in the upper ocean from high resolution sea surface height. Geophys. Res. Lett. 2009, 36, L12603. [CrossRef] 20. Isern-Fontanet, J.; Chapron, B.; Lapeyre, G.; Klein, P. Potential use of microwave sea surface temperatures for the estimation of ocean currents. Geophys. Res. Lett. 2006, 33, L24608. [CrossRef] 21. Isern-Fontanet, J.; Shinde, M.; Andersson, C. On the Transfer Function between Surface Fields and the Geostrophic Stream Function in the Mediterranean Sea. J. Phys. Oceanogr. 2014, 44, 1406–1423. [CrossRef] Geostrophic Stream Function in the Mediterranean Sea. J. Phys. Oceanogr. 2014, 44, 1406–1423. [CrossRef] 22. Turiel, A.; Sole, J.; Nieves, V.; Ballabrera-Poy, J.; Garcia-Ladona, E. Tracking oceanic currents by singularity p y g 22. Turiel, A.; Sole, J.; Nieves, V.; Ballabrera-Poy, J.; Garcia-Ladona, E. Tracking oceanic currents by singularity analysis of Microwave Sea Surface Temperature images Remote Sens Environ 2009 in press [CrossRef] 22. Turiel, A.; Sole, J.; Nieves, V.; Ballabrera-Poy, J.; Garcia-Ladona, E. Tracking oceanic currents by singularity analysis of Microwave Sea Surface Temperature images. Remote Sens. Environ. 2009, in press. References Improvement of coastal and mesoscale observation from space: Application to the northwestern Mediterranean Sea. Geophys. Res. Lett. 2013, 40, 2148–2153. [CrossRef] 37. Ping, B.; Su, F.; Meng, Y. An Improved DINEOF Algorithm for Filling Missing Values in Spatio-Temporal Sea Surface Temperature Data. PLoS ONE 2016, 11, e0155928. [CrossRef] 38. Gerber, F.; de Jong, R.; Schaepman, M.E.; Schaepman-Strub, G.; Furrer, R. Predicting Missing Values in Spatio-Temporal Remote Sensing Data. IEEE Trans. Geosci. Remote Sens. 2018, 56, 2841–2853. [CrossRef] 39. Fablet, R.; Rousseau, F. Missing data super-resolution using non-local and statistical priors. In Proceedings of the 2015 IEEE International Conference on Image Processing (ICIP), Quebec City, QC, Canada, 27–30 September 2015; pp. 676–680. [CrossRef] 22 of 22 Remote Sens. 2019, 11, 858 40. Bernard, D.; Boffetta, G.; Celani, A.; Falkovich, G. Inverse Turbulent Cascades and Conformally Invariant Curves. Phys. Rev. Lett. 2007, 98, 024501. [CrossRef] 41. Moazenzadeh, R.; Mohammadi, B.; Shamshirband, S.; Chau, K.W. Coupling a firefly algorithm with support vector regression to predict evaporation in northern Iran. Eng. Appl. Comput. Fluid Mech. 2018, 12, 584–597. [CrossRef] 42. Faizollahzadeh Ardabili, S.; Najafi, B.; Shamshirband, S.; Minaei Bidgoli, B.; Deo, R.C.; Chau, K.W. Computational intelligence approach for modeling hydrogen production: A review. Eng. Appl. Comput. Fluid Mech. 2018, 12, 438–458. [CrossRef] 43. Yaseen, Z.M.; Sulaiman, S.O.; Deo, R.C.; Chau, K.W. An enhanced extreme learning machine model for river flow forecasting: state-of-the-art, practical applications in water resource engineering area and future research direction. J. Hydrol. 2018. [CrossRef] 44. Taormina, R.; Chau, K.W. Data-driven input variable selection for rainfall-runoff modeling using binary-coded particle swarm optimization and Extreme Learning Machines. J. Hydrol. 2015, 529, 1617–1632. [CrossRef] 45. Taherei Ghazvinei, P.; Hassanpour Darvishi, H.; Mosavi, A.; Yusof, K.b.W.; Alizamir, M.; Shamshirband, S.; Chau, K.w. Sugarcane growth prediction based on meteorological parameters using extreme learning machine and artificial neural network. Eng. Appl. Comput. Fluid Mech. 2018, 12, 738–749. [CrossRef] 46. Wu, C.; Chau, K. Rainfall runoff modeling using artificial neural network coupled with singular spectrum analysis. J. Hydrol. 2011, 399, 394–409. [CrossRef] 47. Muja, M.; Lowe, D.G. Scalable nearest neighbor algorithms for high dimensional data. IEEE Trans. Pattern Anal. Mach. Intell. 2014, 36, 2227–2240. [CrossRef] 48. Cleveland, W.S. Robust locally weighted regression and smoothing scatterplots. J. Am. Stat. Assoc. 1979, 74, 829–836. [CrossRef] 49. Gaultier, L.; Ubelmann, C.; Fu, L.L. The Challenge of Using Future SWOT Data for Oceanic Field Reconstruction. J. Atmos. Ocean. Technol. 2015, 33, 119–126. References [CrossRef] c⃝2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
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https://link.springer.com/content/pdf/10.1007%2Fs10337-016-3182-1.pdf
English
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Report from the 18th International Symposium on Advances in Extraction Technologies (ExTech’2016) and the 22nd International Symposium on Separation Science (ISSS’2016), Toruń, 3–6 July 2016
Chromatographia
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Report from the 18th International Symposium on Advances in Extraction Technologies (ExTech’2016) and the 22nd International Symposium on Separation Science (ISSS’2016), Torun´, 3–6 July 2016 Bogusław Buszewski1 Published online: 22 October 2016 © The Author(s) 2016. This article is published with open access at Springerlink.com Province, Mayor of Torun´, and His Magnificence Rector of Nicolaus Copernicus University in Torun´. One might say that history repeats itself. The best confir- mation of that fact is the 18th International Symposium on Advances in Extraction Technologies—ExTech’2016 and the 22nd International Symposium on Separation Sci- ence—ISSS’2016 which took place at the Culture and Con- gress Center in Torun´, 3–6 July 2016. One more time, over 350 specialists from 41 countries specialising in analytical chemistry, particularly the physicochemical methods of separation, met in the Gothic city of Torun´ to summarise their achievements and to present new concepts both in the theory and practice of separation, enrichment, isolation and determination of the entire range of chemical substances. For the first time in history, the two great symposia ExTech and ISSS have been combined as one event. The former pertains to the methods of sample preparation based mainly on the extraction techniques. The latter deals with the phys- icochemical methods of separation and determination of organic and inorganic substances of different molecular mass and structure, both individual substances and their derivatives occurring in different matrices. The symposia were organised by the Committee of Analytical Chemis- try of the Polish Academy of Sciences, Chair of Analytical Chemistry, Faculty of Chemistry of the Nicolaus Coperni- cus University and the Central European Group for Sepa- ration Science (CEGSS). The honorary patronage of this scientific event was assumed by the Minister of Science and Higher Education, Marshal of Kuyavian-Pomeranian Province, Mayor of Torun´, and His Magnificence Rector of Nicolaus Copernicus University in Torun´. p y The program of the symposium was exceptionally rich. It included 49 plenary and panel lectures as well as 22 oral announcements mostly presented by young scientists. Moreover, during the four subject sessions, there were 258 poster presentations. An integral part of the conference were workshops and the exhibition of 17 manufacturers and distributors of equipment, reagents and accessories. During the symposium, particular attention was drawn to the accomplishments of the founders and pioneers of both extraction science (Prof. Walter Ernst) and chromatography (Prof. Mikhail Tswett). The first session was devoted to the theoretical achievements and fundamental aspects in the field of separation methods. It began with an insightful lec- ture by Prof. J. DOI 10.1007/s10337-016-3182-1 Chromatographia (2016) 79:1679–1681 DOI 10.1007/s10337-016-3182-1 Chromatographia (2016) 79:1679–1681 FEATURE ARTICLE 1 Chair of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, 7 Gagarin St., 87‑100 Torun´, Poland * Bogusław Buszewski bbusz@chem.umk.pl Report from the 18th International Symposium on Advances in Extraction Technologies (ExTech’2016) and the 22nd International Symposium on Separation Science (ISSS’2016), Torun´, 3–6 July 2016 Pichon and Dr. D. Thiebaut from France, Prof. L. Chimuka from RSA, Prof. J. Nogueira from Portugal and Prof. G. Ouyang from China). These subjects well correspond with the issues connected with developing new generation of materials such as packings, analytical columns and columns used in micro- or nano- scale (Prof. Z. Jang from China, Prof. E. Psillakis from Greece, Dr. L. Pelit from Turkey, Dr. M. Szumski from Poland and Prof. A. Malik and J. Anderson from the USA). The so-called chip laboratory (pill-lab) is a challenge not only for researchers studying miniaturisation and roboti- sation of the combined process of sample preparation and final determination (Prof. M. Kaljurand from Estonia or Dr. Vaitz from Germany). This issue was superbly presented in the research paper presented by Prof. Z. Brzóska (Poland), who pointed out the possibilities of using these solutions in modern analytics. • C. Molins-Legua, P. Camping-Falco, Y. Moliner-Mar- tinez, J. Vordu-Andres, J. Pla-Tolos & M. Munnos- Ortuno, University of Valencia (Spain), poster S3-P19, • C. Molins-Legua, P. Camping-Falco, Y. Moliner-Mar- tinez, J. Vordu-Andres, J. Pla-Tolos & M. Munnos- Ortuno, University of Valencia (Spain), poster S3-P19, • E. Gijonfriddo, E.A. Souza-Silva, S. De Grazia, X. Li & J. Pawliszyn, University of Waterloo, (Canada), poster S4-P17, • L. Rivoira, S. Studzin´ska, M. Szultka-Młyn´ska, M. C. Bruzzonitti, M. Ligor & B. Buszewski, University of Torino (Italy)/UMK(NCU) Torun´ (Poland), poster S4-P33. • L. Rivoira, S. Studzin´ska, M. Szultka-Młyn´ska, M. C. Bruzzonitti, M. Ligor & B. Buszewski, University of Torino (Italy)/UMK(NCU) Torun´ (Poland), poster S4-P33. The material and book prizes were funded by: Springer, Wiley–VCH, Polygen company, Polish Chemical Society and the Committee of Chemical Analytics of the Polish Academy of Sciences. The jury also awarded two prizes for the oral presenta- tions of young researchers: • M. Buszewska-Forajta & R. Kaliszan, Gdan´ski Medi- cal University (Poland), OP-7, The solutions aimed at the application of these achieve- ments for the determination of toxic substances of endo- and exogenic origin or xenobiotics in different matri- ces, particularly in water, were presented by Prof. H. Lee (Singapore), Prof. M. Bruzzonitti (Italy), Prof. D. Knapp (Germany), Dr. V. Comann (Romania) or Dr. M. Gerstiuk (Ukraine), in cosmetics (Prof. M. Llompart from Spain) or monitoring of technological processes (Prof. E. Rosen- berg from Austria). All this was perfectly complemented by works devoted to the theoretical considerations containing description of separation mechanisms presented by: Prof. S. Report from the 18th International Symposium on Advances in Extraction Technologies (ExTech’2016) and the 22nd International Symposium on Separation Science (ISSS’2016), Torun´, 3–6 July 2016 Pawliszyn (Canada) concerning the accom- plishments and the future of sample preparation technol- ogy. Professor P. Jandera (Czech Republic), laureate of the European Tswett-Nerst award, presented the advances which have been made in multi-dimensional separation techniques. A new concept in characterising stationary phases and columns used in the so-called fast chromatogra- phy was presented by Prof. A. Felinger (Hungary). Profes- sor O. J. Schmitz (Germany) presented new methodological solutions in the use of coupled separation techniques (LC– MS) for determination of biologically active substances. Similarly, the other sessions brought numerous inno- vative and interesting solutions and proposals. They con- cerned such issues as new advances in sample preparation for the needs of biological and environmental analysis including analytics of food and natural products (Prof. E. Stashenko from Columbia, Prof. G. Mills from the UK, Prof. I. Vovk from Slovenia, Prof. D. Corradini from Italy or Prof. H. Jelen´ from Poland). A particular emphasis was placed on the application of multi-dimensional systems * Bogusław Buszewski bbusz@chem.umk.pl 1 3 1 1680 B. Buszewski and coupled and combined systems in the determina- tion of biologically active substances on the cellular level (metabolism and omics) (Prof. H. Górecki from Canada, Prof. L. Mondello from Italy, Dr. J. Trafkowski from Ger- many, Prof. B. Bojko from Poland and Dr. P. Zuvela from South Korea) and monitoring changes which take place in the metabolic pathways and biogenic changes (Prof. M. Markuszewski and Dr. S. Studzin´ska and Dr. K. Skalicka Woz´niak from Poland, Prof. A. Marus´ka from Lithuania, Dr. W. Filipiak and Prof. P. Mochalski from Austria). • J. Mazina, A. Tretjakova, P. Saar-Reismaa, J. Gorbats- ova, M. Kulp, M. Vaher, E. Erme & M. Kaljurand, Tech- nical University, Tallin (Estonia), poster S1-P71, • M. Gładysz, M. Woz´niakiewicz, P.M. Nowak & P. Kos´cielniak, UJ Kraków (Poland), poster S1-P34, • T. Hajek, P. Jandera & M. Stankova, University of Par- dubice (Czech Rep.), poster S2-P17, • M. Skoczylas, Sz. Bocian & B. Buszewski, UMK Torun´ (Poland), poster S2-P35, • M. Skoczylas, Sz. Bocian & B. Buszewski, UMK Torun´ (Poland), poster S2-P35, • M. Matczuk, J. Legat & M. Jarosz, Politechnika War- szawska (Poland), poster S3-P17, • M. Matczuk, J. Legat & M. Jarosz, Politechnika War- szawska (Poland), poster S3-P17, The research paper speeches concerned miniaturisa- tion and robotisation both in the sample preparation and determination of analytes on the sub-ultra traces (Prof. S. Fanali from Italy, Prof. V. 1 3 Report from the 18th International Symposium on Advances in Extraction Technologies (ExTech’2016) and the 22nd International Symposium on Separation Science (ISSS’2016), Torun´, 3–6 July 2016 Pedersen-Bjergaard from Norway, Prof. I. Malinowska (Poland), Dr. T. Edge (UK), Prof. H. Bagheri (Iran), Dr. J. Weiss from Germany, Dr. D. Berek from Slovakia and Prof. J. Koziel (USA). • G. A. Gomez-Rios, N. Reyes-Garces, E. Boyaci & J. Pawliszyn, Waterloo University (Canada), OP-12. • G. A. Gomez-Rios, N. Reyes-Garces, E. Boyaci & J. Pawliszyn, Waterloo University (Canada), OP-12. The prizes in the form of the covered registration fee at the next conferences of ExTech 2017 (Santiago di Compos- tella, Spain) and ISSS 2017 (Vienna, Austria) were spon- sored by the organising committees of these symposia. Moreover, the organising committee of ITP 2017 in Gdan´sk awarded a prize to L. Rivoira (Turin, Italy) by financing the participation in this conference. During ExTech 2016 & ISSS 2016, apart from the up- to-date and abundant scientific program, the organisers provided the participants with an extensive and attractive cultural offer and the presentation of the traditions of the Kuyavian-Pomeranian region and the city of Torun´. The opening concert by Sławek Wiercholski and Nocna Zmi- ana Bluesa band at the Jordanki Congress and Culture Center does not require any comment. It was an excel- lent prelude to the working sessions of the symposium. Similarly, the performance given by the Culture Center from S´wiecie presenting the folk dance, songs and cus- toms of Poland and the region in the setting of the open-air The presented subject matter was also well suited by short oral announcements made by young researchers (20 papers) and research news presented in the form of post- ers (258). The latter were also accompanied by short oral presentation in front of a panel of judges headed by Prof. T. Górecki. The jury evaluated the scientific innovation, the form and manner of the presentation. The winners/laureates of the contest were: 1 3 1 3 1681 Report from the 18th International Symposium on Advances in Extraction Technologies… Ethnographic Museum showed the richness and diversity of Polish culture. All this would not have been possible without the inval- uable financial support of the government institutions, local and regional authorities and commercial companies (Minis- try of Science and Higher Education, Marshal of Kuyavian- Pomeranian region, Mayor of Torun´, Polish Academy of Sciences, companies such as: LECO-Polska, Perlan Tech- nologies, Shim-Pol, AlChem, VWR, TZMO, La Rive and many others. The organisers and the participants express their gratitude for this support on numerous occasions. Report from the 18th International Symposium on Advances in Extraction Technologies (ExTech’2016) and the 22nd International Symposium on Separation Science (ISSS’2016), Torun´, 3–6 July 2016 The show also included a performance by a traditional gypsy band as well as young musical and vocal talents dur- ing a common feast, which warmed up the atmosphere of the meeting. Similarly, the participants enthusiastically received the performance of the Torun´ singer M. Lubomski and his band given after the official gala dinner at Jordanki Congress and Culture Center. The participants thoroughly enjoyed the delicious dishes served by Gołe˛biewscy cater- ing company and the excellent music by Rumin´scy band. An important element of the program was the post-conference sightseeing tour of Torun´ Along the Gothic Trail including a visit to the Live Museum of Gingerbreads. Despite the rainy weather, the participants enjoyed the tour which was con- firmed by numerous letters and expressions of thanks for the organisation and the warm familiar atmosphere. This gives us enormous satisfaction of the well-done important tasks that we were entrusted with and makes us committed to live up to the expectations of the future. Open Access  This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecom- mons.org/licenses/by/4.0/), which permits unrestricted use, distribu- tion, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Prof. Dr. Bogusław Buszewski, DSc. Chairman of the Scientific and Organising Committee Torun´, 15 July 2016 ExTech’2016 & ISSS’2016 1 3
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https://authors.library.caltech.edu/101948/1/Sirunyan2019_Article_SearchForSupersymmetryUsingHig.pdf
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Search for supersymmetry using Higgs boson to diphoton decays at $$ \sqrt{s} $$ = 13 TeV
˜The œJournal of high energy physics/˜The œjournal of high energy physics
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JHEP11(201 Published for SISSA by Springer Received: August 22, 2019 Accepted: November 4, 2019 Published: November 20, 2019 Search for supersymmetry using Higgs boson to diphoton decays at √s = 13 TeV The CMS collaboration E-mail: cms-publication-committee-chair@cern.ch JHEP11(201 Published for SISSA by Springer Received: August 22, 2019 Accepted: November 4, 2019 Published: November 20, 2019 Search for supersymmetry using Higgs boson to diphoton decays at √s = 13 TeV The CMS collaboration E-mail: cms-publication-committee-chair@cern.ch Published for SISSA by Springer Received: August 22, 2019 Accepted: November 4, 2019 Published: November 20, 2019 Received: August 22, 2019 Accepted: November 4, 2019 Published: November 20, 2019 Received: August 22, 2019 Accepted: November 4, 2019 Published: November 20, 2019 JHEP11(2019)109 The CMS collaboration Open Access, Copyright CERN, for the benefit of the CMS Collaboration. The CMS collaboration E-mail: cms-publication-committee-chair@cern.ch E-mail: cms-publication-committee-chair@cern.ch Abstract: A search for supersymmetry (SUSY) is presented where at least one Higgs boson is produced and decays to two photons in the decay chains of pair-produced SUSY particles. Two analysis strategies are pursued: one focused on strong SUSY production and the other focused on electroweak SUSY production. The presence of charged leptons, addi- tional Higgs boson candidates, and various kinematic variables are used to categorize events into search regions that are sensitive to different SUSY scenarios. The results are based on data from proton-proton collisions at the Large Hadron Collider at a center-of-mass energy of 13 TeV collected by the CMS experiment, corresponding to an integrated luminosity of 77.5 fb−1. No statistically significant excess of events is observed relative to the standard model expectations. We exclude bottom squark pair production for bottom squark masses below 530 GeV and a lightest neutralino mass of 1 GeV; wino-like chargino-neutralino pro- duction in gauge-mediated SUSY breaking (GMSB) for chargino and neutralino masses below 235 GeV with a gravitino mass of 1 GeV; and higgsino-like chargino-neutralino pro- duction in GMSB, where the neutralino decays exclusively to a Higgs boson and a gravitino for neutralino masses below 290 GeV. Keywords: Hadron-Hadron scattering (experiments), Supersymmetry, Higgs physics ArXiv ePrint: 1908.08500 https://doi.org/10.1007/JHEP11(2019)109 Contents 1 Introduction 1 2 The CMS detector 3 3 Event simulation 3 4 Event reconstruction and selection 4 5 Analysis strategy 5 6 Backgrounds 8 7 Systematic uncertainties 12 8 Results and interpretation 12 9 Summary 16 A Additional simplified model interpretations 24 The CMS collaboration 30 Contents 1 Introduction 1 2 The CMS detector 3 3 Event simulation 3 4 Event reconstruction and selection 4 5 Analysis strategy 5 6 Backgrounds 8 7 Systematic uncertainties 12 8 Results and interpretation 12 9 Summary 16 A Additional simplified model interpretations 24 The CMS collaboration 30 JHEP11(2019)109 1 Introduction The Higgs boson (H) provides an intriguing opportunity to explore physics beyond the standard model (SM) of particle physics. Many scenarios of physics beyond the SM pos- tulate the existence of cascade decays of heavy states involving Higgs bosons [1, 2]. In minimal supersymmetry (SUSY) [3], a Higgs boson may appear in processes involving the bottom squark (eb), the SUSY partner of the bottom quark. Bottom squarks are produced via strong interactions and then may decay to a Higgs boson, quarks, and the lightest SUSY particle (LSP). Similarly charginos or neutralinos produced through the electroweak interaction may decay to a Higgs boson and the LSP. Of particular interest are gauge- mediated SUSY breaking (GMSB) scenarios, where the lightest neutralino may decay to a Higgs boson and the gravitino LSP (eG) [4, 5]. Similar searches have been performed by the ATLAS and CMS Collaborations using proton-proton (pp) collisions at the CERN LHC at center-of-mass energies of 8 [6, 7] and 13 TeV [8–11]. We search for evidence of SUSY that produces an excess of events with one or more Higgs bosons decaying to two photons and large missing transverse momentum using pp collision data collected by the CMS experiment at the LHC at a center-of-mass energy of 13 TeV in 2016 and 2017, corresponding to an integrated luminosity of 77.5 fb−1. Kinematic – 1 – p p eb1 eb1 eχ0 2 eχ0 2 b H eχ0 1 eχ0 1 H b p p eχ0 2 eχ± 1 W± eχ0 1 eχ0 1 H p p eχ0 1 eχ0 1 H eG eG H p p eχ0 1 eχ0 1 Z eG eG H Figure 1. Diagrams displaying the simplified models that are being considered. Upper left: bottom squark pair production; upper right: wino-like chargino-neutralino production; lower: the two relevant decay modes for higgsino-like neutralino pair production in the GMSB scenario. p p eχ0 2 eχ± 1 W± eχ0 1 eχ0 1 H p p eχ0 1 eχ0 1 Z eG eG H p p eb1 eb1 eχ0 2 eχ0 2 b H eχ0 1 eχ0 1 H b p p eχ0 1 eχ0 1 H eG eG H H b H H JHEP11(2019)109 H Z Figure 1. Diagrams displaying the simplified models that are being considered. 2 The CMS detector The central feature of the CMS detector is a superconducting solenoid of 6 m internal di- ameter, providing a magnetic field of 3.8 T. Within the solenoid volume are a silicon pixel and strip tracker, a lead tungstate crystal electromagnetic calorimeter (ECAL), and a brass and scintillator hadron calorimeter, each composed of a barrel and two endcap sections. Forward calorimeters extend the pseudorapidity (η) coverage provided by the barrel and endcap detectors. Muons are measured in gas-ionization detectors embedded in the steel flux-return yoke outside the solenoid. The first level of the CMS trigger system [12], com- posed of custom hardware processors, uses information from the calorimeters and muon detectors to select the most interesting events in a fixed time interval of less than 4 µs. The high-level trigger processor farm further decreases the event rate from around 100 kHz to less than 1 kHz before data storage. A more detailed description of the CMS detector, to- gether with a definition of the coordinate system used and the relevant kinematic variables, can be found in ref. [13]. JHEP11(2019)109 1 Introduction Upper left: bottom squark pair production; upper right: wino-like chargino-neutralino production; lower: the two relevant decay modes for higgsino-like neutralino pair production in the GMSB scenario. variables that discriminate the SUSY signal from SM backgrounds are used to separate events into several mutually exclusive categories, and the diphoton mass from the H →γγ decay is used to extract the signal from the background. The branching ratio for H →γγ of 0.227% from the SM is assumed. The dominant backgrounds are SM production of diphoton and photon+jets, which are modeled by functional fits to the diphoton mass distribution. The SM Higgs boson background constitutes a small fraction of the background for most of the phase space used in the search and is estimated from simulation samples. We have designed a new analysis to extend our sensitivity to both strong and elec- troweak SUSY production over the previously published result [8]. Two analysis strategies are pursued: one focuses on the electroweak production of charginos and neutralinos by introducing additional event categories containing one or two charged-lepton candidates, thereby enhancing the sensitivity to SUSY signatures involving W and Z bosons, and the other is optimized for strong production by categorizing events in the number of jets and the number of jets identified as originating from the fragmentation of b quarks (“b- tagged”). The use of the two strategies enhances the overall sensitivity of the search, and increases the robustness of the result by exploring alternative phase space regions. Finally, we interpret the results in various simplified model scenarios of SUSY as summarized in figure 1, including bottom squark pair production, chargino-neutralino, and neutralino-pair production. In this paper, we discuss the CMS detector in section 2, the event simulation in sec- tion 3, the event reconstruction and selection in section 4, the analysis strategy in section 5, the background estimation in section 6, the systematic uncertainties in section 7, and the results and interpretations in section 8. A summary is given in section 9. – 2 – 3 Event simulation Simulated Monte Carlo (MC) event samples are used to model the SM Higgs boson backgrounds and the SUSY signal models. Simulated samples of SM Higgs boson pro- duction through gluon fusion, vector boson fusion, associated production with a W or a Z boson, b¯bH, and t¯tH are generated using the next-to-leading order (NLO) Mad- Graph5 amc@nlo v2.2.2 [14] event generator. The Higgs boson mass is assumed to be 125 GeV for the simulated event samples and is within the uncertainty of the currently best measured value [15, 16]. The Higgs boson production cross sections are taken from ref. [17] and are computed to next-to-next-to-leading order plus next-to-next-to-leading logarithm in the quantum chromodynamics (QCD) coupling constant and to NLO in the electroweak coupling constant. For the gluon fusion production mode, the sample is gen- erated with up to two extra partons from initial-state radiation (ISR) at NLO accuracy and uses the FxFx matching scheme described in ref. [18]. The SUSY signal MC sam- ples are generated using MadGraph5 amc@nlo at leading order accuracy with up to two extra partons in the matrix element calculations, with the MLM matching scheme described in ref. [19]. For samples simulating the 2016 data set, pythia v8.212 [20] is used to model the fragmentation and parton showering with the CUETP8M1 tune [21], while for samples simulating the 2017 data set, pythia v8.226 is used with the CP5 [22] tune. The NNPDF3.0 [23] and NNPDF3.1 [24] parton distribution function (PDF) sets are used for the 2016 and 2017 simulation samples, respectively. The production cross section for squark pair production is computed at NLO plus next-to-leading logarithmic (NLL) accuracy in QCD [25–30] under the assumption that all SUSY particles other than those in the relevant diagram are too heavy to participate in the interaction. The cross sections for higgsino pair production are computed at NLO+NLL precision in the limit of mass-degenerate higgsinos eχ0 2, eχ± 1 , and eχ0 1, with all the other sparticles assumed to be heavy and decoupled [31–33]. Following the convention of real mixing matrices and signed – 3 – neutralino or chargino masses [34], we set the mass of eχ0 1 (eχ0 2) to positive (negative) values. The product of the third and fourth elements of the corresponding rows of the neutralino mixing matrix N is +0.5 (−0.5). The elements U12 and V12 of the chargino mixing matrices are set to 1. 3 Event simulation The SM Higgs boson background samples are simulated using a Geant4-based model [35] of the CMS detector. To cover the large SUSY signal parameter space in reasonable computation time, the signal model samples are simulated with the CMS fast simulation package [36, 37], which has been validated to produce accurate predictions of ob- ject identification efficiencies and momentum resolution. All simulated events include the effects of additional pp interactions in the same or adjacent beam bunch crossings (pileup), and are processed with the same chain of reconstruction programs used for collision data. JHEP11(2019)109 To improve the MadGraph modeling of ISR in the SUSY signal MC samples, we apply a shape correction as a function of the multiplicity of ISR jets for bottom squark pair production and as a function of the transverse momentum (pISR T ) of the chargino- neutralino system for chargino-neutralino production, derived from studies of t¯t and Z +jets events, respectively [38]. The correction factors vary between 0.92 and 0.51 for the ISR jet multiplicity between one and six, and between 1.18 and 0.78 for pISR T between 125 and 600 GeV. The corrections have a small effect on the signal yields for all the simplified models considered at the level of about 1%. For the bottom squark pair production signal model, the full effect of the correction is propagated as a systematic uncertainty. For the chargino-neutralino production one half of effect of the correction is propagated as a systematic uncertainty. 4 Event reconstruction and selection The search with the 2016 data set uses events selected by the diphoton high-level trigger, which requires two photons with pT above 30 and 18 GeV for the leading and subleading photons, respectively. For the 2017 data set, to cope with the increased instantaneous luminosity, the pT requirement on the subleading photon was increased to 22 GeV in order to reduce the trigger rate. The efficiency of the trigger for events with two identified photons is above 98%. Events are reconstructed using the CMS particle flow (PF) algorithm [39], which uses the information from the tracker, calorimeter, and muon systems to construct an optimized global description of the event. The reconstructed vertex with the largest value of summed physics-object p2 T is taken to be the primary interaction vertex. The physics objects used in this context are the objects returned by a jet finding algorithm [40, 41] applied to all charged tracks associated with the vertex under consideration, plus the corresponding associated missing transverse momentum. As the signal is predominantly produced in the central region of the detector, we select events with at least two photons reconstructed in the barrel region (|η| < 1.44). The measured energy of photons is corrected for clustering and local geometric effects using an energy regression trained on Monte Carlo (MC) simulation, and calibrated using a combination of π0 →γγ, η →γγ, and Z →ee candidates [42]. The regression also – 4 – provides an estimate of the uncertainty of the energy measurement that is used to separate events into high- and low-resolution categories. The photons are required to satisfy the photon identification requirements based on electromagnetic shower shape, hadronic to electromagnetic energy ratio, and isolation around the photon candidate. A photon is considered isolated if the pT sum of the PF candidates from charged and neutral hadrons and photons within a cone of 0.3 in ∆R = √ (∆η)2 + (∆φ)2, where φ is the azimuthal angle in radians, are each below a set threshold. The isolation sums are corrected for the effect of pileup by subtracting the average energy deposited as estimated by the pileup energy density ρ [43]. If the photon is matched to a reconstructed electron that is inconsistent with a conversion candidate, it is discarded. A loose working point is used for the photon identification, which has an efficiency of approximately 90%, uniform in pT and η. 4 Event reconstruction and selection The leading (subleading) photon is required to have pT/mγγ > 0.33 (0.25), where mγγ is the reconstructed diphoton mass. The diphoton mass is required to be larger than 100 GeV. The two photons with the largest pT, selected according to the identification criteria above, are considered to be the decay products of the Higgs boson candidate. JHEP11(2019)109 The PF candidates are clustered into jets using the anti-kT algorithm [40, 41] with a distance parameter of 0.4. Jet energy corrections are applied and derived based on a combination of simulation studies, accounting for the nonlinear detector response and the presence of pileup, together with in-situ measurements of the energy balance in dijet and γ+jet events using the methods described in ref. [44]. Jets originating from a heavy-flavor parton are identified by the combined secondary vertex (CSVv2) tagger algorithm [45] using a loose working point. The resulting efficiency is about 80%, while the mistag rate for light-quark and gluon jets is approximately 10%. We identify each jet with pT > 20 GeV that satisfies the loose working point as a b-tagged jet. Other jets with pT > 30 GeV and |η| < 2.4 are considered in this analysis for the purpose of jet counting. Electrons and muons in the region |η| < 2.4 and with pT > 20 GeV are selected from the PF candidates, and a loose identification working point is used. Jets that overlap with the selected electrons, muons, and photons in a cone of size ∆R = 0.4 are discarded. Electrons in a cone of size ∆R = 1.0 and muons in a cone of size ∆R = 0.5 around the selected photons are discarded. A larger veto cone is used for electrons to suppress photon conversions. The transverse component of the negative vectorial sum of the momenta of all PF candidates is the missing transverse momentum ⃗pmiss T , and its magnitude is defined as pmiss T . Dedicated filters [46] reject events with possible beam halo contamination or anomalous noise in the calorimeter systems that can give rise to a large pmiss T . 5 Analysis strategy Two analysis strategies are pursued that employ two alternative event categorization schemes: one focused on electroweak production (EWP analysis) of charginos and neu- tralinos; and another focused on strong production (SP analysis) of bottom squarks. For both strategies, we define event categories based on the pT of the diphoton Higgs boson candidate, and the presence of additional Z, W, or H →b¯b candidates. Within each event category, we define search region bins based on the number of jets and b-tagged jets, and the – 5 – values of kinematic variables that discriminate between SUSY signal and SM backgrounds events. Finally, to test specific SUSY simplified model hypotheses, we perform an unbinned extended maximum likelihood fit to the diphoton mass distribution, simultaneously in all of the search bins defined for each analysis. The dominant background results from SM production of diphoton or photon+jets, and is collectively referred to as the nonresonant background. This background exhibits a regular falling shape as validated in the MC simulation samples, and is modeled with a fit to a family of falling functions independently in each search region bin as described in the next section. The SM Higgs boson background and the SUSY signal model under test exhibit a resonant shape in the diphoton mass and are constrained to the MC simulation predictions within uncertainties. A more detailed discussion of the background fit model and the systematic uncertainties can be found in sections 6 and 7, respectively. JHEP11(2019)109 In the EWP approach, we build upon the strategy employed in a previous publica- tion [8], which categorized events according to the pT of the diphoton Higgs boson candi- date, the presence of an additional Higgs boson candidate, the estimated diphoton mass resolution, and the values of the “razor” kinematic variables [47, 48]. In addition, we add event categories with one or two identified leptons, and further optimize the binning in the kinematic variables for the enlarged data set. The bin boundaries have been chosen to yield the best expected signal significance as estimated using simulation predictions of the signal and background yields. These enhancements improve the signal sensitivity to electroweak production of charginos and neutralinos. By isolating events with a Z, W, or H →b¯b candidate in addition to the H →γγ candidate, we improve the sensitivity to the simplified signal models shown in figure 1. 5 Analysis strategy The Higgs boson candidate and any additional identified leptons or jets are clustered into two hemispheres (megajets) according to the razor megajet algorithm [48], which minimizes the sum of the squared-invariant-mass values of the two megajets. In order to form two hemispheres, we require that events have at least one identified lepton or jet in addition to the Higgs boson candidate. The razor variables [47, 48] MR and R2 are then computed as follows: MR ≡ q (|⃗p j1| + |⃗p j2|)2 −(pzj1 + pzj2)2, (5.1) R2 ≡ MR T MR 2 , (5.2) (5.1) (5.2) where ⃗p is the momentum of a megajet, pz is its longitudinal component, and j1 and j2 are used to label the two megajets. In the definition of R2, the variable MR T is defined as: MR T ≡ s pmiss T (pTj1 + pTj2) −⃗pmiss T · (⃗pT j1 + ⃗pT j2) 2 . (5.3) (5.3) 2 The razor variables MR and R2 provide discrimination between SUSY signal models and SM background processes, with SUSY signals typically having large values of MR and R2, while the SM diphoton and photon+jets backgrounds exhibit a falling spectrum in each variable. – 6 – – 6 – The selected events are first categorized according to the number of electrons or muons. Events with two same-flavor opposite-sign leptons are placed in the “Two-Lepton” category if the dilepton mass satisfies the constraint |mZ −mℓℓ| ≤20 GeV. Among the remaining events, those with at least one muon (electron) are placed in the “Muon” (“Electron”) category, with the Muon category taking precedence. Events in the Electron and Muon categories are further subdivided into the “High-pT” and “Low-pT” subcategories depend- ing on whether the pT of the Higgs boson candidate is larger or smaller than 110 GeV. For events which do not have any leptons, we search for pairs of b-tagged jets, whose mass is between 95 and 140 GeV, and place them into the “Hb¯b” category. If no such jet-pairs are found, then we search for pairs of b-tagged jets whose mass is between 60 and 95 GeV, and place them into the “Zb¯b” category. Events in the Hb¯b and Zb¯b categories are also further subdivided into the High-pT and Low-pT subcategories using the same criteria stated above. 5 Analysis strategy Among the remaining events, those with the pT of the Higgs boson candidate larger than 110 GeV are placed in the High-pT category. Finally, the remaining events are categorized as “High-Res” or “Low-Res” if the diphoton mass resolution estimate σm/m is smaller or larger than 0.85%, respectively, with σm defined as: JHEP11(2019)109 JHEP11(2019)109 σm = 1 2 q (σEγ1/Eγ1)2 + (σEγ2/Eγ2)2, (5.4) (5.4) where Eγ1,2 is the energy of each photon and σEγ1,2 is the estimated energy resolution for each photon. The choice of the 0.85% threshold was made to be identical to past results [8], which was previously optimized for signal to background discrimination. The leptonic categories select SUSY events containing decays to W or Z bosons; the Hb¯b (Zb¯b) categories select events that contain an additional Higgs (Z) boson, which decays to a pair of b jets; the High-pT category selects SUSY events producing high-pT Higgs bosons; and the separation into the High-Res and Low-Res categories further improves the discrimination between any signal containing an H →γγ candidate and non-resonant background in the remaining event sample. Finally, to distinguish SUSY signal events from the SM background, each event category is further divided into bins in the MR and R2 variables, provided there are a sufficient number of data events in the diphoton mass sideband to be able to estimate the background. These bins define the exclusive search regions. For all categories except the Two-Lepton category, we impose the requirement MR > 150 GeV to suppress the SM backgrounds. In the SP approach, we optimize the event categorization for strong production of bottom squark pairs, which typically produce a larger number of jets and b-tagged jets. An alternative clustering algorithm is employed, following ref. [49], to produce two hemispheres referred to as pseudojets, and the kinematic variable mT2 [50] is calculated as mT2 = min ⃗p missX(1) T +⃗p missX(2) T =⃗p miss T h max  m(1) T , m(2) T i , (5.5) (5.5) where ⃗p missX(i) T (with i=1,2) are trial vectors obtained by decomposing ⃗pmiss T and m(i) T , the transverse masses obtained by pairing any of these trial vectors with one of the two pseudojets. The minimization is performed over all trial momenta satisfying the ⃗pmiss T con- straint. 5 Analysis strategy The pγγ T /mγγ and mT2 kinematic variables are used to enhance the discrimination – 7 – between the SUSY signal and the SM background. Two bins in the mT2 variable are used: mT2 < 30 and mT2 ≥30 GeV; and three bins in pγγ T /mγγ: 0–0.6, 0.6–1.0 and ≥1.0. Events are also separated into the Two-Lepton, Muon, Electron, Hb¯b, and Zb¯b cat- egories following the same procedure as described above for the EWP approach. The remaining events are separated into the hadronic categories depending on the number of jets and b-tagged jets. Within each of the event categories, the exclusive search region bins are then defined based on the values of the pγγ T /mγγ and mT2 observables. A summary of the 35 search region bins is shown in table 1 for the EWP analysis and of the 64 search region bins in tables 2 and 3 for the SP analysis. Finally, to test specific SUSY simplified model hypotheses, we perform a combined simultaneous fit using all the search regions defined for each analysis. The final result for each signal model is obtained from the analysis with the best expected sensitivity. The diphoton mass distribution is fit independently in each search region, while the expected yields for the SM Higgs background and SUSY signal model among the different search regions are constrained to the predicted values. JHEP11(2019)109 Search region bins with large values of pγγ T and large values of the kinematic variables MR and mT2 yield the best sensitivity for SUSY signals with larger squark or neutralino masses, as backgrounds are heavily suppressed. The event categories with one lepton, two leptons, a Z →b¯b candidate, or a H →b¯b candidate yield increasingly better sensitivity for more compressed regions as the neutralino mass approaches the Higgs boson mass. 6 Backgrounds Two types of backgrounds can be identified for this search: a nonresonant one stemming from the SM production of diphotons or a photon and a jet, and a resonant background from SM Higgs boson production. To model the nonresonant background, a set of possible functions is chosen from sums of exponential functions, sums of Bernstein polynomials, Laurent series, and sums of power-law functions. To determine the best functional form, two alternative strategies are followed for the EWP and SP analyses. As we do not know a priori the exact shape of the background, it is important that the functional form used is capable of adequately describing a sufficiently large range of background shapes to cover potential systematic effects that affect the shapes. At the same time we do not want to arbitrarily increase the number of fit parameters without yielding additional robustness against systematic uncertainties. The EWP analysis uses the Akaike information criterion (AIC) [51] to determine which functional forms are most appropriate to describe the background spectrum. The same procedure was employed in the previous version of this search [8]. Bias tests are performed by drawing random events using one functional form and fitting the resulting pseudo-data set to another functional form. The functional form with the best AIC measure passing the bias test is chosen to describe the nonresonant background. For the SP analysis, the background fit is performed by discrete profiling using the “envelope” method [52]. The background functional form is treated as a discrete nuisance parameter in the likelihood fit. A penalty is assigned to the likelihood for each parameter in – 8 – Bin number Category pγγ T (GeV) MR (GeV) R2 EWP 0 Two-Lepton No req. No req. No req. 6 Backgrounds EWP 1 Muon High-pT ≥110 ≥150 ≥0.0 EWP 2 Muon Low-pT 0–110 ≥150 ≥0.0 EWP 3 Electron High-pT ≥110 ≥150 ≥0.0 EWP 4 Electron Low-pT 0–110 ≥150 0.000–0.055 EWP 5 Electron Low-pT 0–110 ≥150 0.055–0.125 EWP 6 Electron Low-pT 0–110 ≥150 ≥0.125 EWP 7 Hb¯b High-pT ≥110 ≥150 0.000–0.080 EWP 8 Hb¯b High-pT ≥110 ≥150 ≥0.080 EWP 9 Hb¯b Low-pT 0–110 ≥150 0.000–0.080 EWP 10 Hb¯b Low-pT 0–110 ≥150 ≥0.080 EWP 11 Zb¯b High-pT ≥110 ≥150 0.000–0.035 EWP 12 Zb¯b High-pT ≥110 ≥150 0.035–0.090 EWP 13 Zb¯b High-pT ≥110 ≥150 ≥0.090 EWP 14 Zb¯b Low-pT 0–110 ≥150 0.000–0.035 EWP 15 Zb¯b Low-pT 0–110 ≥150 0.035–0.090 EWP 16 Zb¯b Low-pT 0–110 ≥150 ≥0.090 EWP 17 High-pT ≥110 ≥150 ≥0.260 EWP 18 High-pT ≥110 150–250 0.170–0.260 EWP 19 High-pT ≥110 ≥250 0.170–0.260 EWP 20 High-pT ≥110 ≥150 0.000–0.110 EWP 21 High-pT ≥110 150–350 0.110–0.170 EWP 22 High-pT ≥110 ≥350 0.110–0.170 EWP 23 High-Res 0–110 ≥150 ≥0.325 EWP 24 High-Res 0–110 ≥150 0.285–0.325 EWP 25 High-Res 0–110 ≥150 0.225–0.285 EWP 26 High-Res 0–110 ≥150 0.000–0.185 EWP 27 High-Res 0–110 150–200 0.185–0.225 EWP 28 High-Res 0–110 ≥200 0.185–0.225 EWP 29 Low-Res 0–110 ≥150 ≥0.325 EWP 30 Low-Res 0–110 ≥150 0.285–0.325 EWP 31 Low-Res 0–110 ≥150 0.225–0.285 EWP 32 Low-Res 0–110 ≥150 0.000–0.185 EWP 33 Low-Res 0–110 150–200 0.185–0.225 EWP 34 Low-Res 0–110 ≥200 0.185–0.225 A summary of the search region bins used in the EWP analysis. Events are ories based on the number of leptons, the presence of H →b¯b candidates, γγ candidate, and the estimated diphoton mass resolution. The High-Res and are defined by the estimated diphoton resolution mass σm/m being smaller %, respectively. For the Two-Lepton category, “No req.” means that no require the given observables. JHEP11(2019)109 Table 1. A summary of the search region bins used in the EWP analysis. Events are separated into categories based on the number of leptons, the presence of H →b¯b candidates, the pT of the H →γγ candidate, and the estimated diphoton mass resolution. The High-Res and Low-Res categories are defined by the estimated diphoton resolution mass σm/m being smaller or larger than 0.85%, respectively. For the Two-Lepton category, “No req.” means that no requirements are placed on the given observables. Table 1. A summary of the search region bins used in the EWP analysis. 6 Backgrounds Events are separated into categories based on the number of leptons, the presence of H →b¯b candidates, the pT of the H →γγ candidate, and the estimated diphoton mass resolution. The High-Res and Low-Res categories are defined by the estimated diphoton resolution mass σm/m being smaller or larger than 0.85%, respectively. For the Two-Lepton category, “No req.” means that no requirements are placed on the given observables. – 9 – Bin number Bin name Category pγγ T /mγγ mT2 (GeV) SP 0 Zℓℓ Two-Lepton No req. No req. SP 1 1µ p0 T, m0 T2 Muon 0.0–0.6 0–30 SP 2 1µ p0 T, m30 T2 Muon 0.0–0.6 ≥30 SP 3 1µ p75 T , m0 T2 Muon 0.6–1.0 0–30 SP 4 1µ p75 T , m30 T2 Muon 0.6–1.0 ≥30 SP 5 1µ p125 T , m0 T2 Muon ≥1.0 0–30 SP 6 1µ p125 T , m30 T2 Muon ≥1.0 ≥30 SP 7 1e p0 T, m0 T2 Electron 0.0–0.6 0–30 SP 8 1e p0 T, m30 T2 Electron 0.0–0.6 ≥30 SP 9 1e p75 T , m0 T2 Electron 0.6–1.0 0–30 SP 10 1e p75 T , m30 T2 Electron 0.6–1.0 ≥30 SP 11 1e p125 T , m0 T2 Electron ≥1.0 0–30 SP 12 1e p125 T , m30 T2 Electron ≥1.0 ≥30 SP 13 Zb¯b p0 T, m0 T2 Zb¯b 0.0–0.6 0–30 SP 14 Zb¯b p75 T , m0 T2 Zb¯b 0.6–1.0 0–30 SP 15 Zb¯b p125 T , m0 T2 Zb¯b ≥1.0 0–30 SP 16 Zb¯b p0 T, m30 T2 Zb¯b 0.0–0.6 ≥30 SP 17 Zb¯b p75 T , m30 T2 Zb¯b 0.6–1.0 ≥30 SP 18 Zb¯b p125 T , m30 T2 Zb¯b ≥1.0 ≥30 SP 19 Hb¯b p0 T, m0 T2 Hb¯b 0.0–0.6 0–30 SP 20 Hb¯b p75 T , m0 T2 Hb¯b 0.6–1.0 0–30 SP 21 Hb¯b p125 T , m0 T2 Hb¯b ≥1.0 0–30 SP 22 Hb¯b p0 T, m30 T2 Hb¯b 0.0–0.6 ≥30 SP 23 Hb¯b p75 T , m30 T2 Hb¯b 0.6–1.0 ≥30 SP 24 Hb¯b p125 T , m30 T2 Hb¯b ≥1.0 ≥30 Table 2. A summary of the search region bins in the leptonic and Higgs boson categories used in the SP analysis, along with the requirements on pγγ T /mγγ and mT2. There are no explicit requirements on the number of jets or b-tagged jets for these categories. 6 Backgrounds For the Two-Lepton category, “No req.” means that no requirements are placed on the given observables. JHEP11(2019)109 Table 2. A summary of the search region bins in the leptonic and Higgs boson categories used in the SP analysis, along with the requirements on pγγ T /mγγ and mT2. There are no explicit requirements on the number of jets or b-tagged jets for these categories. For the Two-Lepton category, “No req.” means that no requirements are placed on the given observables. the function. The envelope with the best likelihood is determined by the discrete profiling method taking penalties into account. These two alternative background modeling methods were studied in a past CMS measurement of the SM Higgs process in the diphoton decay channel and similar accuracy is expected [53]. the function. The envelope with the best likelihood is determined by the discrete profiling method taking penalties into account. These two alternative background modeling methods were studied in a past CMS measurement of the SM Higgs process in the diphoton decay channel and similar accuracy is expected [53]. The shape of the SM Higgs boson background and the SUSY signals is modeled by a double Crystal Ball function [54, 55], fitted to the diphoton mass distribution from the MC simulation separately in each search region bin. The parameters of each double Crystal Ball function are held constant in the signal extraction fit procedure. The normalization of the SM Higgs boson background in each bin is constrained to the MC simulation prediction to within systematic uncertainties. – 10 – Bin number Bin name Jets b-tagged jets pγγ T /mγγ mT2 (GeV) SP 25 0j, ≥0b, p0 T 0 No req. 0.0–0.6 No req. SP 26 0j, ≥0b, p75 T 0 No req. 0.6–1.0 No req. SP 27 0j, ≥0b, p125 T 0 No req. ≥1.0 No req. 6 Backgrounds SP 28 1–3j, 0b, p0 T, m0 T2 1–3 0 0.0–0.6 0–30 SP 29 1–3j, 0b, p0 T, m30 T2 1–3 0 0.0–0.6 ≥30 SP 30 1–3j, 0b, p75 T , m0 T2 1–3 0 0.6–1.0 0–30 SP 31 1–3j, 0b, p75 T , m30 T2 1–3 0 0.6–1.0 ≥30 SP 32 1–3j, 0b, p125 T , m0 T2 1–3 0 ≥1.0 0–30 SP 33 1–3j, 0b, p125 T , m30 T2 1–3 0 ≥1.0 ≥30 SP 34 1–3j, 1b, p0 T, m0 T2 1–3 1 0.0–0.6 0–30 SP 35 1–3j, 1b, p0 T, m30 T2 1–3 1 0.0–0.6 ≥30 SP 36 1–3j, 1b, p75 T , m0 T2 1–3 1 0.6–1.0 0–30 SP 37 1–3j, 1b, p75 T , m30 T2 1–3 1 0.6–1.0 ≥30 SP 38 1–3j, 1b, p125 T , m0 T2 1–3 1 ≥1.0 0–30 SP 39 1–3j, 1b, p125 T , m30 T2 1–3 1 ≥1.0 ≥30 SP 40 1–3j, ≥2b, p0 T, m0 T2 1–3 ≥2 0.0–0.6 0–30 SP 41 1–3j, ≥2b, p0 T, m30 T2 1–3 ≥2 0.0–0.6 ≥30 SP 42 1–3j, ≥2b, p75 T , m0 T2 1–3 ≥2 0.6–1.0 0–30 SP 43 1–3j, ≥2b, p75 T , m30 T2 1–3 ≥2 0.6–1.0 ≥30 SP 44 1–3j, ≥2b, p125 T , m0 T2 1–3 ≥2 ≥1.0 0–30 SP 45 1–3j, ≥2b, p125 T , m30 T2 1–3 ≥2 ≥1.0 ≥30 SP 46 ≥4j, 0b, p0 T, m0 T2 ≥4 0 0.0–0.6 0–30 SP 47 ≥4j, 0b, p0 T, m30 T2 ≥4 0 0.0–0.6 ≥30 SP 48 ≥4j, 0b, p75 T , m0 T2 ≥4 0 0.6–1.0 0–30 SP 49 ≥4j, 0b, p75 T , m30 T2 ≥4 0 0.6–1.0 ≥30 SP 50 ≥4j, 0b, p125 T , m0 T2 ≥4 0 ≥1.0 0–30 SP 51 ≥4j, 0b, p125 T , m30 T2 ≥4 0 ≥1.0 ≥30 SP 52 ≥4j, 1b, p0 T, m0 T2 ≥4 1 0.0–0.6 0–30 SP 53 ≥4j, 1b, p0 T, m30 T2 ≥4 1 0.0–0.6 ≥30 SP 54 ≥4j, 1b, p75 T , m0 T2 ≥4 1 0.6–1.0 0–30 SP 55 ≥4j, 1b, p75 T , m30 T2 ≥4 1 0.6–1.0 ≥30 SP 56 ≥4j, 1b, p125 T , m0 T2 ≥4 1 ≥1.0 0–30 SP 57 ≥4j, 1b, p125 T , m30 T2 ≥4 1 ≥1.0 ≥30 SP 58 ≥4j, ≥2b, p0 T, m0 T2 ≥4 ≥2 0.0–0.6 0–30 SP 59 ≥4j, ≥2b, p0 T, m30 T2 ≥4 ≥2 0.0–0.6 ≥30 SP 60 ≥4j, ≥2b, p75 T , m0 T2 ≥4 ≥2 0.6–1.0 0–30 SP 61 ≥4j, ≥2b, p75 T , m30 T2 ≥4 ≥2 0.6–1.0 ≥30 SP 62 ≥4j, ≥2b, p125 T , m0 T2 ≥4 ≥2 ≥1.0 0–30 SP 63 ≥4j, ≥2b, p125 T , m30 T2 ≥4 ≥2 ≥1.0 ≥30 le 3. Table 3. A summary of the search region bins in the leptonic and Higgs boson categories used in the SP analysis, along with the requirements on pγγ T /mγγ and mT2. “No req.” means that no requirements are placed on the given observables. 7 Systematic uncertainties The dominant systematic uncertainties in this search are the normalization and shape of the nonresonant background associated with the fitted functional form. They are propa- gated by profiling the associated unconstrained functional form parameters. The fraction of the total uncertainty due to the nonresonant background fit ranges from 75% to 99%, and is above 90% for most search region bins. The subdominant systematic uncertainties in the SM Higgs boson background and SUSY signal are propagated through independent log-normal nuisance parameters that take both theoretical and instrumental effects into account. These systematic uncertainties affect the event yield predictions of the SM Higgs boson background and SUSY signal in the different search region bins, and are propagated as shape uncertainties. The independent systematic effects considered include missing higher-order QCD corrections, PDFs, trigger and object selection efficiencies, jet energy scale uncertainties, b-tagging efficiency, lepton identification efficiencies, fast simulation pmiss T modeling, and the uncertainty in the integrated luminosity. The typical size of these effects on the signal and background yields are summarized in table 4, and are approxi- mately the same for the SP and EWP analyses. Systematic uncertainties due to missing higher-order corrections are estimated by the use of the procedure outlined in ref. [56], where the factorization (µF) and renormalization (µR) scales are varied independently by factors of 0.5 and 2.0. The PDF systematic uncertainties are propagated for the SM Higgs background as a shape uncertainty using the LHC4PDF procedure [57]. JHEP11(2019)109 Because of the imperfect simulation of the effects of pileup and transparency loss from radiation damage in the ECAL crystals, we observe some simulation mismodeling of the estimated mass resolution, which can migrate events between the High-Res and Low-Res event categories of the EWP analysis. As a result, a systematic uncertainty of 10–24%, measured using a Z →e+e−control sample, is propagated to the prediction of the SM Higgs boson background and SUSY signal yields in the High-Res and Low-Res event categories. The systematic uncertainty in the photon energy scale is implemented as a Gaussian-distributed nuisance parameter that shifts the Higgs boson mass peak position, constrained in the fit to lie within approximately 1% of the nominal Higgs boson mass observed in simulation. The systematic uncertainty for the modeling of the ISR for the signal process is also propagated. 6 Backgrounds A summary of the search region bins in the leptonic and Higgs boson categories u he SP analysis, along with the requirements on pγγ T /mγγ and mT2. “No req.” means tha irements are placed on the given observables JHEP11(2019)109 Table 3. A summary of the search region bins in the leptonic and Higgs boson categories used in the SP analysis, along with the requirements on pγγ T /mγγ and mT2. “No req.” means that no requirements are placed on the given observables. Table 3. A summary of the search region bins in the leptonic and Higgs boson categories used in the SP analysis, along with the requirements on pγγ T /mγγ and mT2. “No req.” means that no requirements are placed on the given observables. – 11 – 8 Results and interpretation The fit results for the search region bins including the data yields, fitted background, and signal yields are summarized in tables 5 and 6 for the SP analysis and in table 7 for the EWP analysis. Example fit results are shown in figure 2 to illustrate the background-only and signal plus background fits. We observe no statistically significant deviation from the SM background expectation. The search results are interpreted in terms of limits on the product of the production cross section and branching fraction for simplified models of bottom squark pair production and chargino-neutralino production indicated in figure 1. In the case of bottom squark pair – 12 – Uncertainty source Uncertainty size (%) PDFs and QCD scale variations 10–30 (SM Higgs boson) 5–10 (EWK SUSY signal) 15–30 (Strong SUSY signal) Signal ISR modeling 5–25 σm/m categorization 10–24 Fast simulation pmiss T modeling 3–16 Luminosity 2.3–2.5 Trigger and selection efficiency 3 Lepton efficiency 4 Jet energy scale 1–5 Photon energy scale 1 b-tagging efficiency 4 H →γγ branching fraction 2 Table 4. Summary of systematic uncertainties on the SM Higgs boson background and signal yield predictions, and the size of their effect on the signal yield. JHEP11(2019)109 Table 4. Summary of systematic uncertainties on the SM Higgs boson background and signal yie predictions, and the size of their effect on the signal yield. Table 4. Summary of systematic uncertainties on the SM Higgs boson background and signal yield predictions, and the size of their effect on the signal yield. production, we consider the scenario where the bottom squark subsequently decays to a bottom quark and the next-to-lightest neutralino (eχ0 2), where the eχ0 2 decays to a Higgs boson and the LSP (eχ0 1). The mass splitting between the eχ0 2 and eχ0 1 is assumed to be 130 GeV, slightly above threshold to produce an on-shell Higgs boson. production, we consider the scenario where the bottom squark subsequently decays to a bottom quark and the next-to-lightest neutralino (eχ0 2), where the eχ0 2 decays to a Higgs boson and the LSP (eχ0 1). The mass splitting between the eχ0 2 and eχ0 1 is assumed to be 130 GeV, slightly above threshold to produce an on-shell Higgs boson. In the case of chargino-neutralino production, we consider two different scenarios. 8 Results and interpretation In the first scenario, the pure wino-like charginos (eχ± 1 ) and the eχ0 2 are mass-degenerate and are produced together, with the chargino decaying to a W boson and the eχ0 1 LSP, and the eχ0 2 decaying to a Higgs boson and the LSP. The production cross sections are computed at NLO+NLL accuracy in QCD in the limit of mass-degenerate wino eχ0 2 and eχ± 1 , light bino eχ0 1, and with all the other sparticles assumed to be heavy and decoupled [31–33]. In the second scenario, we consider a GMSB [4, 5] simplified model where higgsino-like charginos and neutralinos are nearly mass-degenerate and are produced in pairs through the following combinations: eχ0 1eχ0 2, eχ0 1eχ± 1 , eχ0 2eχ± 1 , and eχ± 1 eχ∓ 1 . Because of the mass degeneracy, both the eχ0 2 and eχ± 1 will decay to eχ0 1 and other low-pT (soft) particles, leading to a signature with a eχ0 1 pair. Each eχ0 1 will subsequently decay to a Higgs boson and the eG LSP, or to a Z boson and the LSP. We consider the case where the branching fraction of the eχ0 1 →HeG decay is 100%, and the case where the branching fraction of the eχ0 1 →HeG and eχ0 1 →ZeG decays are each 50%. This scenario is represented by the eχ0 1-pair production simplified model shown on figure 1. We show the expected event yields from a representative selection of the different simplified SUSY models considered in the different search region bins of the SP analysis in tables 8 and 9, and in the different search region bins of the EWP analysis in table 10. The details of the particular signal model are described in the caption of table 8. 8 Results and interpretation Following the CLs criterion [58–60], we use the profile likelihood ratio test statistic and the asymptotic formula [61] to evaluate the 95% confidence level (CL) observed and ex- – 13 – Search Bin name Observed Fitted SM Higgs boson region bin data nonresonant bkg bkg SP 0 Zℓℓ 2 1.7 ± 0.2 0.84 ± 0.09 SP 1 1µ p0 T, m0 T2 24 20.0 ± 0.9 1.6 ± 0.1 SP 2 1µ p0 T, m30 T2 10 8.9 ± 1.4 1.1 ± 0.1 SP 3 1µ p75 T , m0 T2 3 2.6 ± 0.5 0.89 ± 0.07 SP 4 1µ p75 T , m30 T2 7 2.4 ± 0.4 0.79 ± 0.07 SP 5 1µ p125 T , m0 T2 4 3.1 ± 0.4 1.0 ± 0.1 SP 6 1µ p125 T , m30 T2 3 2.2 ± 0.4 1.1 ± 0.1 SP 7 1e p0 T, m0 T2 93 87.2 ± 10.6 1.1 ± 0.1 SP 8 1e p0 T, m30 T2 15 13.8 ± 0.9 0.59 ± 0.05 SP 9 1e p75 T , m0 T2 10 18.6 ± 3.0 0.74 ± 0.06 SP 10 1e p75 T , m30 T2 3 4.3 ± 0.3 0.48 ± 0.04 SP 11 1e p125 T , m0 T2 7 6.2 ± 0.4 1.1 ± 0.1 SP 12 1e p125 T , m30 T2 1 1.4 ± 0.2 0.89 ± 0.08 SP 13 Zb¯b p0 T, m0 T2 227 224 ± 17 4.4 ± 0.6 SP 14 Zb¯b p75 T , m0 T2 33 42.2 ± 7.4 1.7 ± 0.2 SP 15 Zb¯b p125 T , m0 T2 15 15.7 ± 3.6 2.9 ± 0.3 SP 16 Zb¯b p0 T, m30 T2 44 43.4 ± 7.5 0.83 ± 0.40 SP 17 Zb¯b p75 T , m30 T2 13 10.8 ± 2.3 0.48 ± 0.13 SP 18 Zb¯b p125 T , m30 T2 5 4.5 ± 0.4 0.82 ± 0.11 SP 19 Hb¯b p0 T, m0 T2 179 179 ± 15 3.4 ± 0.3 SP 20 Hb¯b p75 T , m0 T2 45 41.2 ± 1.9 1.9 ± 0.2 SP 21 Hb¯b p125 T , m0 T2 22 18.4 ± 1.8 3.0 ± 0.9 SP 22 Hb¯b p0 T, m30 T2 47 42.5 ± 7.4 0.93 ± 0.32 SP 23 Hb¯b p75 T , m30 T2 13 12.1 ± 0.8 0.62 ± 0.06 SP 24 Hb¯b p125 T , m30 T2 6 4.4 ± 0.7 1.3 ± 0.2 Table 5. 8 Results and interpretation The observed data, fitted nonresonant background yields, and SM Higgs boson ba ground yields within the mass window between 122 and 129 GeV are shown for each search reg bin in the Hb¯b, Zb¯b, and leptonic categories of the SP analysis. The uncertainties quoted are t fit uncertainties, which include the impact of all systematic uncertainties. The bin names giv short-form description of the search region bin definition which are given in full in table 2. T labels p0 T, p75 T , and p125 T refer to bins defined by the requirement that pγγ T /mγγ is less than 0 between 0.6 and 1.0, and greater than 1.0, respectively. The labels m0 T2 and m30 T2 refer to b defined by the requirement that mT2 is less than and greater than 30 GeV, respectively. JHEP11(2019)109 Table 5. The observed data, fitted nonresonant background yields, and SM Higgs boson back- ground yields within the mass window between 122 and 129 GeV are shown for each search region bin in the Hb¯b, Zb¯b, and leptonic categories of the SP analysis. The uncertainties quoted are the fit uncertainties, which include the impact of all systematic uncertainties. The bin names give a short-form description of the search region bin definition which are given in full in table 2. The labels p0 T, p75 T , and p125 T refer to bins defined by the requirement that pγγ T /mγγ is less than 0.6, between 0.6 and 1.0, and greater than 1.0, respectively. The labels m0 T2 and m30 T2 refer to bins defined by the requirement that mT2 is less than and greater than 30 GeV, respectively. Table 5. The observed data, fitted nonresonant background yields, and SM Higgs boson back- ground yields within the mass window between 122 and 129 GeV are shown for each search region bin in the Hb¯b, Zb¯b, and leptonic categories of the SP analysis. The uncertainties quoted are the fit uncertainties, which include the impact of all systematic uncertainties. The bin names give a short-form description of the search region bin definition which are given in full in table 2. The labels p0 T, p75 T , and p125 T refer to bins defined by the requirement that pγγ T /mγγ is less than 0.6, between 0.6 and 1.0, and greater than 1.0, respectively. 8 Results and interpretation [GeV] γ γ m 100 110 120 130 140 150 160 170 180 Events / GeV 0 2 4 6 8 10 12 14 16 18 20 Data Signal plus background Total background Signal SP analysis bin 21 0 T2 m 125 T p bb H CMS (13 TeV) -1 77.5 fb [GeV] γ γ m 100 110 120 130 140 150 160 170 180 Events / GeV 0 2 4 6 8 10 12 14 16 18 20 Data Full background model Nonresonant background SP analysis bin 21 0 T2 m 125 T p bb H CMS (13 TeV) -1 77.5 fb JHEP11(2019)109 [GeV] γ γ m 100 110 120 130 140 150 160 170 180 Events / GeV 0 2 4 6 8 10 12 14 Data Full background model Nonresonant background EWP analysis bin 2 category T Muon Low-p 110 GeV ≤ γ γ T p CMS (13 TeV) -1 77.5 fb [GeV] γ γ m 100 110 120 130 140 150 160 170 180 Events / GeV 0 2 4 6 8 10 12 14 Data Signal plus background Total background Signal EWP analysis bin 2 category T Muon Low-p 110 GeV ≤ γ γ T p CMS (13 TeV) -1 77.5 fb Figure 2. The diphoton mass distribution for two example search bin is shown with the background-only fit (left) and the signal-plus-background fit (right) to illustrate the signal ex- traction procedure. The search region bins shown corresponds to the Hb¯b p125 T , m0 T2 category, bin 21, of the SP analysis (upper) and the Muon Low-pT category, bin 2, of the EWP analysis (lower). of the bottom squark mass and the LSP mass. We exclude bottom squarks with masses below about 530 GeV for an LSP mass of 1 GeV. For the simplified models of chargino-neutralino production, the EWP analysis has slightly better expected sensitivity because of the inclusion of bins with smaller MR and larger R2. Events in such bins typically have lower values of pmiss T and are not in the regions of high signal sensitivity for the SP analysis, while the R2 variable is able to suppress backgrounds more effectively in these regions of phase space. For the wino-like chargino-neutralino production, the limits obtained using the EWP analysis are shown in figure 4 as a function of the chargino mass and the LSP mass. 8 Results and interpretation The labels m0 T2 and m30 T2 refer to bins defined by the requirement that mT2 is less than and greater than 30 GeV, respectively. pected limits on the signal production cross sections. For the simplified models of bottom squark pair production where the bottom squark undergoes a cascade decay to a Higgs boson and the LSP, the SP analysis yields better expected sensitivity because of the bin- ning in the number of jets and b-tagged jets, as more jets and more heavy-flavor jets are produced. The limits obtained using the SP analysis are shown in figure 3, as a function – 14 – [GeV] γ γ m 100 110 120 130 140 150 160 170 180 Events / GeV 0 2 4 6 8 10 12 14 16 18 20 Data Full background model Nonresonant background SP analysis bin 21 0 T2 m 125 T p bb H CMS (13 TeV) -1 77.5 fb [GeV] γ γ m 100 110 120 130 140 150 160 170 180 Events / GeV 0 2 4 6 8 10 12 14 16 18 20 Data Signal plus background Total background Signal SP analysis bin 21 0 T2 m 125 T p bb H CMS (13 TeV) -1 77.5 fb [GeV] γ γ m 100 110 120 130 140 150 160 170 180 Events / GeV 0 2 4 6 8 10 12 14 Data Full background model Nonresonant background EWP analysis bin 2 category T Muon Low-p 110 GeV ≤ γ γ T p CMS (13 TeV) -1 77.5 fb [GeV] γ γ m 100 110 120 130 140 150 160 170 180 Events / GeV 0 2 4 6 8 10 12 14 Data Signal plus background Total background Signal EWP analysis bin 2 category T Muon Low-p 110 GeV ≤ γ γ T p CMS (13 TeV) -1 77.5 fb Figure 2. The diphoton mass distribution for two example search bin is shown with the background-only fit (left) and the signal-plus-background fit (right) to illustrate the signal ex- traction procedure. The search region bins shown corresponds to the Hb¯b p125 T , m0 T2 category, bin 21, of the SP analysis (upper) and the Muon Low-pT category, bin 2, of the EWP analysis (lower). 8 Results and interpretation We exclude chargino masses below about 235 GeV for an LSP mass of 1 GeV. For the higgsino-like chargino-neutralino production simplified models, the limits obtained using the EWP analysis are shown in figure 5 as a function of the chargino mass for the case where the branching fraction of the eχ0 1 →HeG decay is 100%, and for the case where the branching fraction of the eχ0 1 →HeG and eχ0 1 →ZeG decays are both 50%. We exclude charginos below 290 and 230 GeV in the former and latter cases, respectively. The corresponding limits from the EWP analysis as applied to bottom squark production and limits from the SP analysis as applied to chargino-neutralino production are included in the appendix for completeness. – 15 – [GeV] b~ m 250 300 350 400 450 500 550 600 650 700 [GeV] 0 1 χ∼ m 0 50 100 150 200 250 300 350 400 450 500 1 − 10 1 (13 TeV) -1 77.5 fb CMS 1 0 χ∼ bH → 2 0 χ∼ b → b~ , b~ b~ → pp theory 1 s.d. ± Observed experiment 1, 2 s.d. ± Expected 95% CL upper limit on cross section [pb] SP analysis Figure 3. The observed 95% CL upper limits on the bottom squark pair production cross section are shown for the SP analysis. The bold and light solid black contours represent the observed exclusion region and the ±1 standard deviation (s.d.) band, including both experimental and theoretical uncertainties. The analogous red dotted contours represent the expected exclusion region and its ±1 and ±2 s.d. bands. [GeV] b~ m 250 300 350 400 450 500 550 600 650 700 [GeV] 0 1 χ∼ m 0 50 100 150 200 250 300 350 400 450 500 1 − 10 1 (13 TeV) -1 77.5 fb CMS 1 0 χ∼ bH → 2 0 χ∼ b → b~ , b~ b~ → pp theory 1 s.d. ± Observed experiment 1, 2 s.d. ± Expected 95% CL upper limit on cross section [pb] SP analysis JHEP11(2019)109 Figure 3. The observed 95% CL upper limits on the bottom squark pair production cross section are shown for the SP analysis. The bold and light solid black contours represent the observed exclusion region and the ±1 standard deviation (s.d.) band, including both experimental and theoretical uncertainties. 8 Results and interpretation The analogous red dotted contours represent the expected exclusion region and its ±1 and ±2 s.d. bands. The search region bins with large pγγ T in the H →b¯b category yield the best overall sensitivity. For signal models with squark or neutralino masses exceeding the Higgs boson mass by 100 GeV or more, the search region bins with large values of pγγ T and large values of the kinematic variables MR and mT2 in the untagged jet categories of the SP analysis or the High-pT category for the EWP analysis also contribute significantly to the search sensitivity. For more compressed regions of the signal model parameter space, where the neutralino mass approaches the Higgs boson mass, the search region bins with large pγγ T in the leptonic categories contribute significantly to the search sensitivity. The search region bins with small values of pγγ T and small values of the kinematic variables MR, R2, and mT2 typically have low sensitivity to the simplified models considered due to higher levels of background, but are included to maintain inclusivity for this search. 9 Summary band. Figure 4. The observed 95% CL upper limits on the wino-like chargino-neutralino production cross section are shown for the EWP analysis. The bold and light black contours represent the observed exclusion region and the ±1 standard deviation (s.d.) band, including both experimental and theoretical uncertainties. The analogous red dotted contours represent the expected exclusion region and its ±1 s.d. band. [GeV] 1 0 χ∼ Higgsino mass m 150 200 250 300 350 400 450 [pb] excl 95% σ 1 − 10 1 10 2 10 3 10 NLO+NLL theory Observed limit (95% CL) Median expected limit 68% expected 95% expected (100%) G~ H → 1 0 χ∼ ; soft + X 1 0 χ∼ 1 0 χ∼ → j ± 0, χ∼ i ± 0, χ∼ → pp 1 0 χ∼ m ≈ 1 ± χ∼ m ≈ 2 0 χ∼ = 1 GeV; m G~ m EWP analysis (13 TeV) -1 77.5 fb CMS [GeV] 1 0 χ∼ Higgsino mass m 150 200 250 300 350 400 450 [pb] excl 95% σ 1 − 10 1 10 2 10 3 10 NLO+NLL theory Observed limit (95% CL) Median expected limit 68% expected 95% expected (50%) G~ H → 1 0 χ∼ ; soft + X 1 0 χ∼ 1 0 χ∼ → j ± 0, χ∼ i ± 0, χ∼ → pp (50%) G~ Z → 1 0 χ∼ 1 0 χ∼ m ≈ 1 ± χ∼ m ≈ 2 0 χ∼ = 1 GeV; m G~ m EWP analysis (13 TeV) -1 77.5 fb CMS Figure 5. The observed 95% CL upper limits on the production cross section for higgsino-like chargino-neutralino production are shown for the EWP analysis. We present limits in the scenario where the branching fraction of eχ0 1 →HeG decay is 100% (left plot), and where the eχ0 1 →HeG and eχ0 1 →ZeG decays are each 50% (right plot). The dotted and solid black curves represent the expected and observed exclusion region, and the green dark and yellow light bands represent the ±1 and ±2 standard deviation regions, respectively. The red solid and dotted lines show the theoretical production cross section and its uncertainty band. 9 Summary We have presented a search for supersymmetry (SUSY) in the final state with a Higgs boson (H) decaying to a photon pair, using data collected with the CMS detector at the LHC in 2016 and 2017, corresponding to 77.5 fb−1 of integrated luminosity. To improve the sensitivity over previously published results, we pursue two strategies that are optimized for strong and electroweak SUSY production, respectively. Photon pairs in the central region of the detector are used to reconstruct Higgs boson candidates. Charged leptons and b jets are – 16 – [GeV] 0 2 χ∼ = m ± 1 χ∼ m 140 160 180 200 220 240 260 280 300 [GeV] 0 1 χ∼ m 0 20 40 60 80 100 120 140 160 180 200 1 − 10 1 EWP analysis (13 TeV) -1 77.5 fb CMS 0 1 χ∼ H → 0 2 χ∼ , 0 1 χ∼ ± W → ± 1 χ∼ , 0 2 χ∼ ± 1 χ∼ → pp theory 1 s.d. ± Observed experiment 1 s.d. ± Expected 95% CL upper limit on cross section [pb] Figure 4. The observed 95% CL upper limits on the wino-like chargino-neutralino production cross section are shown for the EWP analysis. The bold and light black contours represent the observed exclusion region and the ±1 standard deviation (s.d.) band, including both experimental and theoretical uncertainties. The analogous red dotted contours represent the expected exclusion region and its ±1 s d band [GeV] 0 2 χ∼ = m ± 1 χ∼ m 140 160 180 200 220 240 260 280 300 [GeV] 0 1 χ∼ m 0 20 40 60 80 100 120 140 160 180 200 1 − 10 1 EWP analysis (13 TeV) -1 77.5 fb CMS 0 1 χ∼ H → 0 2 χ∼ , 0 1 χ∼ ± W → ± 1 χ∼ , 0 2 χ∼ ± 1 χ∼ → pp theory 1 s.d. ± Observed experiment 1 s.d. ± Expected 95% CL upper limit on cross section [pb] (13 TeV) -1 77.5 fb JHEP11(2019)109 Figure 4. The observed 95% CL upper limits on the wino-like chargino-neutralino production cross section are shown for the EWP analysis. The bold and light black contours represent the observed exclusion region and the ±1 standard deviation (s.d.) band, including both experimental and theoretical uncertainties. The analogous red dotted contours represent the expected exclusion region and its ±1 s.d. 9 Summary [GeV] 1 0 χ∼ Higgsino mass m 150 200 250 300 350 400 450 [pb] excl 95% σ 1 − 10 1 10 2 10 3 10 NLO+NLL theory Observed limit (95% CL) Median expected limit 68% expected 95% expected (50%) G~ H → 1 0 χ∼ ; soft + X 1 0 χ∼ 1 0 χ∼ → j ± 0, χ∼ i ± 0, χ∼ → pp (50%) G~ Z → 1 0 χ∼ 1 0 χ∼ m ≈ 1 ± χ∼ m ≈ 2 0 χ∼ = 1 GeV; m G~ m EWP analysis (13 TeV) -1 77.5 fb CMS [GeV] 1 0 χ∼ Higgsino mass m 150 200 250 300 350 400 450 [pb] excl 95% σ 1 − 10 1 10 2 10 3 10 NLO+NLL theory Observed limit (95% CL) Median expected limit 68% expected 95% expected (100%) G~ H → 1 0 χ∼ ; soft + X 1 0 χ∼ 1 0 χ∼ → j ± 0, χ∼ i ± 0, χ∼ → pp 1 0 χ∼ m ≈ 1 ± χ∼ m ≈ 2 0 χ∼ = 1 GeV; m G~ m EWP analysis (13 TeV) -1 77.5 fb CMS Figure 5. The observed 95% CL upper limits on the production cross section for higgsino-like chargino-neutralino production are shown for the EWP analysis. We present limits in the scenario where the branching fraction of eχ0 1 →HeG decay is 100% (left plot), and where the eχ0 1 →HeG and eχ0 1 →ZeG decays are each 50% (right plot). The dotted and solid black curves represent the expected and observed exclusion region, and the green dark and yellow light bands represent the ±1 and ±2 standard deviation regions, respectively. The red solid and dotted lines show the theoretical production cross section and its uncertainty band. 9 Summary – 17 – Search Bin name Observed Fitted SM Higgs boson region bin data nonresonant bkg bkg SP 25 0j, ≥0b, p0 T 53 252 53 662 ± 104 973 ± 68 SP 26 0j, ≥0b, p75 T 586 574 ± 27 33.3 ± 4.1 SP 27 0j, ≥0b, p125 T 51 49.5 ± 8.0 7.4 ± 0.8 SP 28 1–3j, 0b, p0 T, m0 T2 14 648 14 753 ± 138 308 ± 33 SP 29 1–3j, 0b, p0 T, m30 T2 2732 2725 ± 10 125 ± 10 SP 30 1–3j, 0b, p75 T , m0 T2 781 708 ± 30 101 ± 9 SP 31 1–3j, 0b, p75 T , m30 T2 103 101 ± 11 0.90 ± 0.38 SP 32 1–3j, 0b, p125 T , m0 T2 47 46.6 ± 7.7 0.95 ± 0.28 SP 33 1–3j, 0b, p125 T , m30 T2 52 37.2 ± 6.9 3.9 ± 0.6 SP 34 1–3j, 1b, p0 T, m0 T2 4184 4149 ± 7 78.4 ± 7.7 SP 35 1–3j, 1b, p0 T, m30 T2 928 902 ± 34 35.3 ± 3.1 SP 36 1–3j, 1b, p75 T , m0 T2 273 270 ± 19 36.4 ± 3.1 SP 37 1–3j, 1b, p75 T , m30 T2 75 78.0 ± 10.0 1.3 ± 0.1 SP 38 1–3j, 1b, p125 T , m0 T2 52 43.7 ± 7.5 0.97 ± 0.26 SP 39 1–3j, 1b, p125 T , m30 T2 38 30.8 ± 6.3 3.7 ± 0.8 SP 40 1–3j, ≥2b, p0 T, m0 T2 312 292 ± 19 5.6 ± 0.8 SP 41 1–3j, ≥2b, p0 T, m30 T2 79 79.6 ± 10.1 3.0 ± 0.3 SP 42 1–3j, ≥2b, p75 T , m0 T2 37 34.3 ± 6.6 4.5 ± 0.6 SP 43 1–3j, ≥2b, p75 T , m30 T2 26 24.0 ± 5.6 0.57 ± 0.06 SP 44 1–3j, ≥2b, p125 T , m0 T2 16 12.3 ± 0.8 0.54 ± 0.10 SP 45 1–3j, ≥2b, p125 T , m30 T2 15 10.0 ± 0.8 1.7 ± 0.2 SP 46 ≥4j, 0b, p0 T, m0 T2 2429 2426 ± 7 35.3 ± 2.6 SP 47 ≥4j, 0b, p0 T, m30 T2 339 339 ± 21 12.9 ± 1.2 SP 48 ≥4j, 0b, p75 T , m0 T2 118 97.8 ± 11.2 11.1 ± 2.2 SP 49 ≥4j, 0b, p75 T , m30 T2 15 19.5 ± 3.1 0.16 ± 0.05 SP 50 ≥4j, 0b, p125 T , m0 T2 13 10.0 ± 1.7 0.08 ± 1.76 SP 51 ≥4j, 0b, p125 T , m30 T2 7 6.5 ± 0.6 0.73 ± 0.18 SP 52 ≥4j, 1b, p0 T, m0 T2 833 800 ± 32 12.3 ± 2.5 SP 53 ≥4j, 1b, p0 T, m30 T2 132 135 ± 13 4.6 ± 0.3 SP 54 ≥4j, 1b, p75 T , m0 T2 33 42.5 ± 7.4 4.8 ± 0.7 SP 55 ≥4j, 1b, p75 T , m30 T2 13 20.2 ± 5.1 0.35 ± 0.04 SP 56 ≥4j, 1b, p125 T , m0 T2 10 11.4 ± 1.5 0.34 ± 0.04 SP 57 ≥4j, 1b, p125 T , m30 T2 9 8.4 ± 0.6 0.97 ± 0.11 SP 58 ≥4j, ≥2b, p0 T, m0 T2 90 88.4 ± 10.7 1.1 ± 0.3 SP 59 ≥4j, ≥2b, p0 T, m30 T2 25 20.9 ± 4.6 0.52 ± 0.06 SP 60 ≥4j, ≥2b, p75 T , m0 T2 11 8.7 ± 0.6 0.84 ± 0.17 SP 61 ≥4j, ≥2b, p75 T , m30 T2 12 11.5 ± 3.7 0.26 ± 0.09 SP 62 ≥4j, ≥2b, p125 T , m0 T2 6 3.7 ± 0.4 0.24 ± 0.08 SP 63 ≥4j, ≥2b, p125 T , m30 T2 4 5.2 ± 1.1 0.69 ± 0.09 JHEP11(2019)109 Table 6. 9 Summary The observed data, fitted nonresonant background yields, and SM Higgs boson back- ground yields within the mass window between 122 and 129 GeV are shown for each search region bin in the all-hadronic categories of the SP analysis. The uncertainties quoted are the fit uncer- tainties, which include the impact of all systematic uncertainties. The bin names give a short-form description of the search region bin definition which are given in full in table 3. The labels p0 T, p75 T , and p125 T refer to bins defined by the requirement that pγγ T /mγγ is less than 0.6, between 0.6 and 1.0, and greater than 1.0, respectively. The labels m0 T2 and m30 T2 refer to bins defined by the requirement that mT2 is less than and greater than 30 GeV, respectively. Table 6. The observed data, fitted nonresonant background yields, and SM Higgs boson back- ground yields within the mass window between 122 and 129 GeV are shown for each search region bin in the all-hadronic categories of the SP analysis. The uncertainties quoted are the fit uncer- tainties, which include the impact of all systematic uncertainties. The bin names give a short-form description of the search region bin definition which are given in full in table 3. The labels p0 T, p75 T , and p125 T refer to bins defined by the requirement that pγγ T /mγγ is less than 0.6, between 0.6 and 1.0, and greater than 1.0, respectively. The labels m0 T2 and m30 T2 refer to bins defined by the requirement that mT2 is less than and greater than 30 GeV, respectively. 9 Summary – 18 – Search Category Observed Fitted SM Higgs boson region bin data nonresonant bkg bkg EWP 0 Two-Lepton 2 1.5 ± 0.4 1.1 ± 0.6 EWP 1 Muon High-pT 11 6.2 ± 0.9 3.7 ± 0.8 EWP 2 Muon Low-pT 28 15.8 ± 1.4 3.0 ± 0.8 EWP 3 Electron High-pT 17 11.9 ± 1.3 3.4 ± 1.1 EWP 4 Electron Low-pT 8 5.2 ± 0.8 0.6 ± 0.2 EWP 5 Electron Low-pT 18 31.5 ± 1.9 0.9 ± 0.4 EWP 6 Electron Low-pT 9 13.7 ± 1.3 0.7 ± 0.3 EWP 7 Hb¯b High-pT 9 7.0 ± 0.9 1.2 ± 0.4 EWP 8 Hb¯b High-pT 19 17.8 ± 1.5 3.8 ± 0.7 EWP 9 Hb¯b Low-pT 34 25.8 ± 1.8 0.8 ± 0.1 EWP 10 Hb¯b Low-pT 60 51.0 ± 2.4 1.9 ± 0.3 EWP 11 Zb¯b High-pT 3 7.2 ± 1.1 0.5 ± 0.1 EWP 12 Zb¯b High-pT 17 14.0 ± 1.3 2.8 ± 1.1 EWP 13 Zb¯b High-pT 10 9.4 ± 1.1 1.3 ± 0.3 EWP 14 Zb¯b Low-pT 27 35.2 ± 2.0 0.8 ± 0.2 EWP 15 Zb¯b Low-pT 84 75.1 ± 2.9 2.5 ± 1.3 EWP 16 Zb¯b Low-pT 45 46.3 ± 2.3 1.2 ± 0.4 EWP 17 High-pT 11 14.4 ± 1.3 1.8 ± 0.2 EWP 18 High-pT 31 21.8 ± 1.6 2.1 ± 0.4 EWP 19 High-pT 11 13.5 ± 1.3 1.2 ± 0.3 EWP 20 High-pT 1834 1648 ± 14 248 ± 38 EWP 21 High-pT 91 100.2 ± 3.7 8.9 ± 1.5 EWP 22 High-pT 12 14.4 ± 1.4 1.2 ± 0.2 EWP 23 High-Res 30 20.6 ± 1.6 0.6 ± 0.2 EWP 24 High-Res 46 49.1 ± 4.0 1.5 ± 0.5 EWP 25 High-Res 9 17.0 ± 1.4 0.4 ± 0.1 EWP 26 High-Res 5186 5057 ± 25 219 ± 42 EWP 27 High-Res 53 63.0 ± 2.6 2.4 ± 1.0 EWP 28 High-Res 19 17.7 ± 1.5 0.5 ± 0.1 EWP 29 Low-Res 26 33.8 ± 2.1 0.3 ± 0.1 EWP 30 Low-Res 61 65.8 ± 3.0 0.9 ± 0.2 EWP 31 Low-Res 24 18.3 ± 1.5 0.2 ± 0.1 EWP 32 Low-Res 5548 5328 ± 22 141 ± 27 EWP 33 Low-Res 78 79.1 ± 2.9 1.4 ± 0.4 EWP 34 Low-Res 25 23.7 ± 1.8 0.4 ± 0.1 ble 7. Table 7. The observed data, fitted nonresonant background yields, and SM Higgs boson back- ground yields within the mass window between 122 and 129 GeV are shown for each search region bin of the EWP analysis. The uncertainties quoted are the fit uncertainties, which include the impact of all systematic uncertainties. 9 Summary The observed data, fitted nonresonant background yields, and SM Higgs boson ba und yields within the mass window between 122 and 129 GeV are shown for each search reg JHEP11(2019)109 – 19 – Search Bin name HH ZH WH (200,1) eb (450,1) eb (450,300) region bin SP 0 Zℓℓ 0.15 ± 0.02 1.2 ± 0.2 0.0 ± 0.0 0.07 ± 0.01 0.10 ± 0.01 SP 1 1µ p0 T, m0 T2 0.67 ± 0.11 0.22 ± 0.04 0.63 ± 0.07 0.69 ± 0.06 0.10 ± 0.01 SP 2 1µ p0 T, m30 T2 0.59 ± 0.10 0.23 ± 0.04 1.1 ± 0.1 0.88 ± 0.07 0.09 ± 0.01 SP 3 1µ p75 T , m0 T2 0.68 ± 0.09 0.22 ± 0.03 0.44 ± 0.04 0.40 ± 0.03 0.17 ± 0.01 SP 4 1µ p75 T , m30 T2 0.74 ± 0.09 0.27 ± 0.03 1.0 ± 0.1 0.45 ± 0.04 0.18 ± 0.01 SP 5 1µ p125 T , m0 T2 1.6 ± 0.3 0.51 ± 0.08 0.72 ± 0.14 0.24 ± 0.02 1.2 ± 0.1 SP 6 1µ p125 T , m30 T2 1.7 ± 0.3 0.58 ± 0.10 1.7 ± 0.3 0.32 ± 0.03 1.6 ± 0.1 SP 7 1e p0 T, m0 T2 0.43 ± 0.12 0.18 ± 0.03 0.41 ± 0.05 0.52 ± 0.04 0.06 ± 0.00 SP 8 1e p0 T, m30 T2 0.43 ± 0.11 0.19 ± 0.04 0.78 ± 0.12 0.52 ± 0.03 0.05 ± 0.00 SP 9 1e p75 T , m0 T2 0.45 ± 0.11 0.19 ± 0.02 0.30 ± 0.03 0.27 ± 0.02 0.12 ± 0.01 SP 10 1e p75 T , m30 T2 0.48 ± 0.09 0.22 ± 0.02 0.66 ± 0.07 0.29 ± 0.02 0.12 ± 0.01 SP 11 1e p125 T , m0 T2 1.3 ± 0.3 0.46 ± 0.09 0.60 ± 0.11 0.24 ± 0.02 0.87 ± 0.07 SP 12 1e p125 T , m30 T2 1.5 ± 0.3 0.57 ± 0.09 1.4 ± 0.3 0.28 ± 0.02 1.1 ± 0.1 SP 13 Zb¯b p0 T, m0 T2 1.3 ± 0.2 0.50 ± 0.08 0.09 ± 0.02 3.0 ± 0.2 0.29 ± 0.02 SP 14 Zb¯b p75 T , m0 T2 1.3 ± 0.1 0.52 ± 0.06 0.05 ± 0.01 1.7 ± 0.1 0.63 ± 0.04 SP 15 Zb¯b p125 T , m0 T2 2.9 ± 0.5 1.2 ± 0.2 0.11 ± 0.02 1.3 ± 0.1 5.1 ± 0.3 SP 16 Zb¯b p0 T, m30 T2 1.1 ± 0.2 0.49 ± 0.08 0.12 ± 0.02 2.5 ± 0.3 0.13 ± 0.01 SP 17 Zb¯b p75 T , m30 T2 1.1 ± 0.1 0.52 ± 0.07 0.13 ± 0.02 1.5 ± 0.1 0.31 ± 0.03 SP 18 Zb¯b p125 T , m30 T2 2.3 ± 0.4 1.3 ± 0.2 0.25 ± 0.05 1.1 ± 0.1 2.2 ± 0.2 SP 19 Hb¯b p0 T, m0 T2 2.9 ± 0.5 0.81 ± 0.14 0.03 ± 0.01 5.9 ± 0.4 1.4 ± 0.1 SP 20 Hb¯b p75 T , m0 T2 3.3 ± 0.3 0.91 ± 0.13 0.04 ± 0.01 3.4 ± 0.3 2.6 ± 0.2 SP 21 Hb¯b p125 T , m0 T2 9.6 ± 1.8 2.6 ± 0.5 0.06 ± 0.01 3.0 ± 0.2 22.7 ± 1.7 SP 22 Hb¯b p0 T, m30 T2 2.5 ± 0.4 0.71 ± 0.10 0.10 ± 0.01 4.7 ± 0.5 0.49 ± 0.05 SP 23 Hb¯b p75 T , m30 T2 2.9 ± 0.3 0.82 ± 0.10 0.11 ± 0.02 3.0 ± 0.3 0.86 ± 0.08 SP 24 Hb¯b p125 T , m30 T2 8.2 ± 1.6 2.4 ± 0.4 0.15 ± 0.04 2.8 ± 0.2 8.7 ± 0.7 Table 8. 9 Summary The expected signal yields for the SUSY simplified model signals considered are shown for each search region bin in the Hb¯b, Zb¯b, and leptonic categories of the SP analysis. The bin names give a short-form description of the search region bin definition which are given in full in table 2. The labels p0 T, p75 T , and p125 T refer to bins defined by the requirement that pγγ T /mγγ is less than 0.6, between 0.6 and 1.0, and greater than 1.0, respectively. The labels m0 T2 and m30 T2 refer to bins defined by the requirement that mT2 is less than and greater than 30 GeV, respectively. The labels HH and ZH refer to the signal models for higgsino-like chargino and neutralino production where the branching fractions of the decays eχ0 1 →HeG and eχ0 1 →ZeG are 100% and 0% , and 50% and 50%, respectively. For the above two scenarios, the mass of the chargino and next-to-lightest neutralino is 175 GeV, while the LSP mass is 45 GeV. The label WH (200,1) refers to the signal model for wino-like chargino and neutralino production, where the mass of the chargino and next-to-lightest neutralino is 200 GeV and the LSP mass is 1 GeV. The labels eb (450,1) and eb (450,300) refer to the signal models for bottom squark pair production where the bottom squark mass is 450 GeV and the LSP mass is 1 and 300 GeV, respectively. JHEP11(2019)109 used to tag the decay products of an additional boson, while kinematic quantities such as mT2 and the razor variables MR and R2 are used to suppress standard model backgrounds. Data driven fits determine the shape and normalization of the nonresonant background. 9 Summary – 20 – Search Bin name HH ZH WH (200,1) eb (450,1) eb (450,300) region bin SP 25 0j, ≥0b, p0 T 3.9 ± 0.6 2.9 ± 0.5 2.6 ± 0.3 2.7 ± 0.1 0.0 ± 0.0 SP 26 0j, ≥0b, p75 T 2.4 ± 0.3 2.1 ± 0.2 1.8 ± 0.2 0.54 ± 0.02 0.0 ± 0.0 SP 27 0j, ≥0b, p125 T 1.7 ± 0.2 2.7 ± 0.4 1.7 ± 0.2 0.15 ± 0.01 0.01 ± 0.00 SP 28 1–3j, 0b, p0 T, m0 T2 4.7 ± 0.8 2.7 ± 0.4 2.9 ± 0.3 4.2 ± 0.5 0.03 ± 0.00 SP 29 1–3j, 0b, p0 T, m30 T2 4.7 ± 0.5 2.6 ± 0.3 2.1 ± 0.2 1.6 ± 0.3 0.03 ± 0.01 SP 30 1–3j, 0b, p75 T , m0 T2 9.0 ± 1.5 5.1 ± 0.9 3.1 ± 0.6 0.73 ± 0.15 0.27 ± 0.05 SP 31 1–3j, 0b, p75 T , m30 T2 0.21 ± 0.04 0.10 ± 0.02 0.10 ± 0.01 0.34 ± 0.09 0.04 ± 0.01 SP 32 1–3j, 0b, p125 T , m0 T2 0.18 ± 0.02 0.10 ± 0.01 0.07 ± 0.01 0.15 ± 0.04 0.05 ± 0.01 SP 33 1–3j, 0b, p125 T , m30 T2 0.66 ± 0.14 0.35 ± 0.07 0.19 ± 0.04 0.14 ± 0.03 0.35 ± 0.07 SP 34 1–3j, 1b, p0 T, m0 T2 6.1 ± 0.9 2.2 ± 0.3 1.1 ± 0.1 7.1 ± 1.0 0.12 ± 0.02 SP 35 1–3j, 1b, p0 T, m30 T2 6.6 ± 0.6 2.4 ± 0.2 0.81 ± 0.06 3.4 ± 0.3 0.20 ± 0.02 SP 36 1–3j, 1b, p75 T , m0 T2 13.7 ± 2.1 5.1 ± 0.9 1.4 ± 0.2 2.2 ± 0.3 1.7 ± 0.2 SP 37 1–3j, 1b, p75 T , m30 T2 0.23 ± 0.03 0.09 ± 0.01 0.08 ± 0.01 0.82 ± 0.13 0.27 ± 0.04 SP 38 1–3j, 1b, p125 T , m0 T2 0.36 ± 0.04 0.13 ± 0.01 0.07 ± 0.00 0.39 ± 0.06 0.59 ± 0.08 SP 39 1–3j, 1b, p125 T , m30 T2 1.2 ± 0.2 0.47 ± 0.09 0.18 ± 0.03 0.37 ± 0.05 3.5 ± 0.5 SP 40 1–3j, ≥2b, p0 T, m0 T2 0.60 ± 0.09 0.21 ± 0.04 0.08 ± 0.01 1.9 ± 0.2 0.43 ± 0.05 SP 41 1–3j, ≥2b, p0 T, m30 T2 0.81 ± 0.07 0.27 ± 0.02 0.07 ± 0.01 1.2 ± 0.1 0.69 ± 0.07 SP 42 1–3j, ≥2b, p75 T , m0 T2 2.0 ± 0.4 0.67 ± 0.11 0.09 ± 0.03 0.98 ± 0.12 5.0 ± 0.6 SP 43 1–3j, ≥2b, p75 T , m30 T2 0.08 ± 0.01 0.03 ± 0.01 0.02 ± 0.01 0.38 ± 0.04 1.3 ± 0.1 SP 44 1–3j, ≥2b, p125 T , m0 T2 0.11 ± 0.03 0.04 ± 0.00 0.03 ± 0.00 0.28 ± 0.03 2.2 ± 0.2 SP 45 1–3j, ≥2b, p125 T , m30 T2 0.44 ± 0.10 0.16 ± 0.03 0.05 ± 0.03 0.37 ± 0.03 15.5 ± 1.3 SP 46 ≥4j, 0b, p0 T, m0 T2 3.9 ± 0.6 3.1 ± 0.5 6.6 ± 0.7 3.3 ± 0.8 0.01 ± 0.00 SP 47 ≥4j, 0b, p0 T, m30 T2 4.2 ± 0.5 3.4 ± 0.4 5.6 ± 0.5 1.2 ± 0.2 0.03 ± 0.01 SP 48 ≥4j, 0b, p75 T , m0 T2 7.5 ± 1.2 6.9 ± 1.2 8.0 ± 1.4 0.56 ± 0.11 0.13 ± 0.03 SP 49 ≥4j, 0b, p75 T , m30 T2 0.14 ± 0.02 0.10 ± 0.01 0.19 ± 0.02 0.52 ± 0.11 0.02 ± 0.00 SP 50 ≥4j, 0b, p125 T , m0 T2 0.16 ± 0.02 0.13 ± 0.02 0.19 ± 0.02 0.25 ± 0.05 0.02 ± 0.00 SP 51 ≥4j, 0b, p125 T , m30 T2 0.81 ± 0.18 0.50 ± 0.11 0.51 ± 0.11 0.27 ± 0.05 0.16 ± 0.03 SP 52 ≥4j, 1b, p0 T, m0 T2 5.0 ± 0.8 2.3 ± 0.3 2.5 ± 0.3 5.1 ± 0.9 0.08 ± 0.01 SP 53 ≥4j, 1b, p0 T, m30 T2 5.4 ± 0.6 2.5 ± 0.2 2.1 ± 0.2 2.3 ± 0.2 0.15 ± 0.02 SP 54 ≥4j, 1b, p75 T , m0 T2 11.4 ± 1.8 5.5 ± 0.9 3.5 ± 0.6 1.4 ± 0.2 1.1 ± 0.1 SP 55 ≥4j, 1b, p75 T , m30 T2 0.27 ± 0.03 0.14 ± 0.02 0.18 ± 0.02 1.2 ± 0.2 0.11 ± 0.01 SP 56 ≥4j, 1b, p125 T , m0 T2 0.33 ± 0.03 0.14 ± 0.01 0.17 ± 0.01 0.81 ± 0.13 0.15 ± 0.03 SP 57 ≥4j, 1b, p125 T , m30 T2 1.4 ± 0.3 0.65 ± 0.12 0.42 ± 0.09 0.76 ± 0.12 1.5 ± 0.2 SP 58 ≥4j, ≥2b, p0 T, m0 T2 0.42 ± 0.06 0.18 ± 0.03 0.16 ± 0.03 1.4 ± 0.1 0.18 ± 0.02 SP 59 ≥4j, ≥2b, p0 T, m30 T2 0.65 ± 0.07 0.26 ± 0.03 0.13 ± 0.02 0.86 ± 0.08 0.35 ± 0.03 SP 60 ≥4j, ≥2b, p75 T , m0 T2 1.6 ± 0.3 0.67 ± 0.11 0.24 ± 0.07 0.71 ± 0.08 2.4 ± 0.3 SP 61 ≥4j, ≥2b, p75 T , m30 T2 0.08 ± 0.02 0.03 ± 0.00 0.03 ± 0.01 0.73 ± 0.07 0.44 ± 0.04 SP 62 ≥4j, ≥2b, p125 T , m0 T2 0.14 ± 0.03 0.05 ± 0.02 0.03 ± 0.00 0.53 ± 0.06 0.82 ± 0.09 SP 63 ≥4j, ≥2b, p125 T , m30 T2 0.51 ± 0.11 0.20 ± 0.06 0.11 ± 0.03 0.57 ± 0.05 6.4 ± 0.6 Table 9. 9 Summary The expected signal yields for the SUSY simplified model signals considered are shown for each search region bin in the all-hadronic categories of the SP analysis. The bin names give a short-form description of the search region bin definition which are given in full in table 3. The labels p0 T, p75 T , and p125 T refer to bins defined by the requirement that pγγ T /mγγ is less than 0.6, between 0.6 and 1.0, and greater than 1.0, respectively. The labels m0 T2 and m30 T2 refer to bins defined by the requirement that mT2 is less than and greater than 30 GeV, respectively. The labels for the different signal models are explained in detail in the caption of table 8. JHEP11(2019)109 Table 9. The expected signal yields for the SUSY simplified model signals considered are shown for each search region bin in the all-hadronic categories of the SP analysis. The bin names give a short-form description of the search region bin definition which are given in full in table 3. The labels p0 T, p75 T , and p125 T refer to bins defined by the requirement that pγγ T /mγγ is less than 0.6, between 0.6 and 1.0, and greater than 1.0, respectively. The labels m0 T2 and m30 T2 refer to bins defined by the requirement that mT2 is less than and greater than 30 GeV, respectively. The labels for the different signal models are explained in detail in the caption of table 8. 9 Summary – 21 – Search Category HH ZH WH (200,1) eb (450,1) eb (450,300) region bin EWP 0 Two-Lepton 0.2 ± 0.01 1.6 ± 0.1 0.0 ± 0.000 0.2 ± 0.1 0.1 ± 0.03 EWP 1 Muon High-pT 4.5 ± 0.2 1.5 ± 0.1 3.3 ± 0.2 4.4 ± 1.8 0.9 ± 0.4 EWP 2 Muon Low-pT 1.6 ± 0.04 0.6 ± 0.02 1.7 ± 0.05 0.6 ± 0.2 1.8 ± 0.7 EWP 3 Electron High-pT 4.0 ± 0.2 1.5 ± 0.1 2.7 ± 0.1 3.2 ± 1.3 0.8 ± 0.3 EWP 4 Electron Low-pT 0.5 ± 0.01 0.2 ± 0.01 0.9 ± 0.04 0.1 ± 0.03 0.7 ± 0.3 EWP 5 Electron Low-pT 0.3 ± 0.01 0.1 ± 0.01 0.2 ± 0.02 0.2 ± 0.1 0.2 ± 0.1 EWP 6 Electron Low-pT 0.3 ± 0.01 0.2 ± 0.004 0.3 ± 0.02 0.1 ± 0.04 0.4 ± 0.2 EWP 7 Hb¯b High-pT 11.9 ± 0.5 3.4 ± 0.2 0.2 ± 0.01 4.3 ± 4.3 4.7 ± 1.9 EWP 8 Hb¯b High-pT 9.1 ± 0.6 2.5 ± 0.2 0.1 ± 0.005 30.1 ± 12.1 2.2 ± 0.8 EWP 9 Hb¯b Low-pT 1.9 ± 0.2 0.6 ± 0.05 0.1 ± 0.003 0.8 ± 1.0 6.5 ± 2.8 EWP 10 Hb¯b Low-pT 1.2 ± 0.1 0.4 ± 0.04 0.03 ± 0.002 3.7 ± 1.5 2.4 ± 1.0 EWP 11 Zb¯b High-pT 3.2 ± 0.3 1.7 ± 0.2 0.3 ± 0.02 0.6 ± 0.6 1.9 ± 0.8 EWP 12 Zb¯b High-pT 1.3 ± 0.2 0.6 ± 0.1 0.1 ± 0.01 4.8 ± 2.2 0.4 ± 0.2 EWP 13 Zb¯b High-pT 2.5 ± 0.1 1.1 ± 0.1 0.1 ± 0.02 2.3 ± 2.2 1.0 ± 0.4 EWP 14 Zb¯b Low-pT 1.7 ± 0.2 0.8 ± 0.1 0.2 ± 0.01 0.1 ± 0.1 3.7 ± 1.5 EWP 15 Zb¯b Low-pT 0.6 ± 0.2 0.2 ± 0.04 0.02 ± 0.002 0.6 ± 0.3 0.8 ± 0.4 EWP 16 Zb¯b Low-pT 1.0 ± 0.05 0.4 ± 0.02 0.04 ± 0.01 0.3 ± 0.3 1.5 ± 0.6 EWP 17 High-pT 5.3 ± 1.6 5.5 ± 0.6 7.2 ± 0.5 0.3 ± 0.2 1.4 ± 0.7 EWP 18 High-pT 1.8 ± 0.1 0.8 ± 0.05 0.5 ± 0.03 0.01 ± 0.1 0.3 ± 0.1 EWP 19 High-pT 6.0 ± 1.4 4.0 ± 0.7 3.6 ± 0.2 0.6 ± 0.4 1.4 ± 0.6 EWP 20 High-pT 42.1 ± 3.9 19.6 ± 1.8 9.1 ± 0.8 40.1 ± 15.8 6.1 ± 2.4 EWP 21 High-pT 4.9 ± 0.2 2.3 ± 0.1 1.4 ± 0.1 0.03 ± 0.04 0.9 ± 0.4 EWP 22 High-pT 7.3 ± 1.2 4.2 ± 0.6 3.0 ± 0.2 1.5 ± 1.4 1.3 ± 0.5 EWP 23 High-Res 1.1 ± 1.2 1.0 ± 0.4 3.0 ± 0.6 0.03 ± 0.02 2.2 ± 1.2 EWP 24 High-Res 1.5 ± 0.5 0.9 ± 0.2 1.1 ± 0.1 0.03 ± 0.01 1.4 ± 0.6 EWP 25 High-Res 0.6 ± 0.3 0.4 ± 0.1 0.6 ± 0.1 0.01 ± 0.2 0.6 ± 0.3 EWP 26 High-Res 13.7 ± 2.1 6.5 ± 1.0 4.4 ± 0.7 4.1 ± 1.7 10.4 ± 4.4 EWP 27 High-Res 0.5 ± 0.1 0.3 ± 0.04 0.2 ± 0.03 0.0 ± 0.000 0.4 ± 0.2 EWP 28 High-Res 0.8 ± 0.2 0.5 ± 0.1 0.6 ± 0.1 0.1 ± 0.2 0.9 ± 0.4 EWP 29 Low-Res 0.7 ± 0.7 0.7 ± 0.3 1.9 ± 0.5 0.02 ± 0.01 1.5 ± 0.8 EWP 30 Low-Res 1.0 ± 0.3 0.5 ± 0.1 0.7 ± 0.2 0.02 ± 0.01 1.0 ± 0.5 EWP 31 Low-Res 0.5 ± 0.4 0.3 ± 0.2 0.4 ± 0.1 0.01 ± 0.003 0.5 ± 0.3 EWP 32 Low-Res 8.4 ± 2.2 4.1 ± 1.0 3.0 ± 0.8 2.7 ± 1.3 7.1 ± 3.6 EWP 33 Low-Res 0.4 ± 0.1 0.2 ± 0.05 0.2 ± 0.04 0.002 ± 0.001 0.2 ± 0.1 EWP 34 Low-Res 0.6 ± 0.2 0.3 ± 0.1 0.4 ± 0.1 0.01 ± 0.01 0.6 ± 0.3 Table 10. 9 Summary The expected signal yields for the SUSY simplified model signals considered are shown for each search region bin of the EWP analysis. The category that each search region bin belongs to is also indicated in the table. The search region bins definitions are summarized in table 1. The labels for the different signal models are explained in detail in the caption of table 8. JHEP11(2019)109 The resonant background from standard model Higgs boson production is estimated from simulation. The results are interpreted in terms of exclusion limits on the production cross section of simplified models of bottom squark pair production and chargino-neutralino production. As a result of the improvements in the event categorization and the larger data set, we extend the mass limits over the previous best results [8] by about 100 GeV for bottom squark pair production and about 50 GeV for chargino-neutralino production. The resonant background from standard model Higgs boson production is estimated from simulation. The results are interpreted in terms of exclusion limits on the production cross section of simplified models of bottom squark pair production and chargino-neutralino production. As a result of the improvements in the event categorization and the larger data set, we extend the mass limits over the previous best results [8] by about 100 GeV for bottom squark pair production and about 50 GeV for chargino-neutralino production. – 22 – We exclude bottom squark pair production for bottom squark masses below 530 GeV for a lightest neutralino mass of 1 GeV; wino-like chargino-neutralino production, for chargino and neutralino (eχ0 1) masses of up to 235 GeV and a gravitino (eG) mass of 1 GeV; and higgsino-like chargino-neutralino production, for chargino and neutralino (eχ0 1) masses of up to 290 and 230 GeV for the cases where the branching fraction of the lightest neutralino eχ0 1 →HeG decay is 100%, and where the branching fractions of the eχ0 1 →HeG and eχ0 1 →ZeG decays are both 50%, respectively. Acknowledgments JHEP11(2019)109 We congratulate our colleagues in the CERN accelerator departments for the excellent per- formance of the LHC and thank the technical and administrative staffs at CERN and at other CMS institutes for their contributions to the success of the CMS effort. In addition, we gratefully acknowledge the computing centers and personnel of the Worldwide LHC Computing Grid for delivering so effectively the computing infrastructure essential to our analyses. Finally, we acknowledge the enduring support for the construction and operation of the LHC and the CMS detector provided by the following funding agencies: BMBWF and FWF (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, FAPERGS, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COL- CIENCIAS (Colombia); MSES and CSF (Croatia); RPF (Cyprus); SENESCYT (Ecuador); MoER, ERC IUT, PUT and ERDF (Estonia); Academy of Finland, MEC, and HIP (Fin- land); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); NKFIA (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); MSIP and NRF (Republic of Korea); MES (Latvia); LAS (Lithuania); MOE and UM (Malaysia); BUAP, CINVESTAV, CONACYT, LNS, SEP, and UASLP-FAI (Mexico); MOS (Montenegro); MBIE (New Zealand); PAEC (Pakistan); MSHE and NSC (Poland); FCT (Portugal); JINR (Dubna); MON, RosAtom, RAS, RFBR, and NRC KI (Russia); MESTD (Serbia); SEIDI, CPAN, PCTI, and FEDER (Spain); MOSTR (Sri Lanka); Swiss Funding Agencies (Switzerland); MST (Taipei); ThEPCenter, IPST, STAR, and NSTDA (Thailand); TUBITAK and TAEK (Turkey); NASU and SFFR (Ukraine); STFC (United Kingdom); DOE and NSF (USA). Individuals have received support from the Marie-Curie program and the European Research Council and Horizon 2020 Grant, contract Nos. 675440, 752730, and 765710 (Eu- ropean Union); the Leventis Foundation; the A.P. Sloan Foundation; the Alexander von Humboldt Foundation; the Belgian Federal Science Policy Office; the Fonds pour la Forma- tion `a la Recherche dans l’Industrie et dans l’Agriculture (FRIA-Belgium); the Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium); the F.R.S.-FNRS and FWO (Belgium) under the “Excellence of Science – EOS” – be.h project n. 30820817; the Beijing Municipal Science & Technology Commission, No. Acknowledgments Z181100004218003; the Ministry of Education, Youth and Sports (MEYS) of the Czech Republic; the Lend¨ulet (“Momentum”) Program and the J´anos Bolyai Research Scholarship of the Hungarian Academy of Sciences, the New National Excellence Program ´UNKP, the NKFIA research – 23 – grants 123842, 123959, 124845, 124850, 125105, 128713, 128786, and 129058 (Hungary); the Council of Science and Industrial Research, India; the HOMING PLUS program of the Foundation for Polish Science, cofinanced from European Union, Regional Develop- ment Fund, the Mobility Plus program of the Ministry of Science and Higher Educa- tion, the National Science Center (Poland), contracts Harmonia 2014/14/M/ST2/00428, Opus 2014/13/B/ST2/02543, 2014/15/B/ST2/03998, and 2015/19/B/ST2/02861, Sonata- bis 2012/07/E/ST2/01406; the National Priorities Research Program by Qatar National Research Fund; the Ministry of Science and Education, grant no. 3.2989.2017 (Russia); the Programa Estatal de Fomento de la Investigaci´on Cient´ıfica y T´ecnica de Excelencia Mar´ıa de Maeztu, grant MDM-2015-0509 and the Programa Severo Ochoa del Principado de As- turias; the Thalis and Aristeia programs cofinanced by EU-ESF and the Greek NSRF; the Rachadapisek Sompot Fund for Postdoctoral Fellowship, Chulalongkorn University and the Chulalongkorn Academic into Its 2nd Century Project Advancement Project (Thailand); the Welch Foundation, contract C-1845; and the Weston Havens Foundation (USA). JHEP11(2019)109 A Additional simplified model interpretations The bold and light solid black contours represent the ved exclusion region and the ±1 standard deviation (s.d.) band, including both experimental heoretical uncertainties. The analogous red dotted contours represent the expected exclusion n and its ±1 s.d. band. [GeV] b~ m 250 300 350 400 450 500 550 600 650 700 [GeV] 0 1 χ∼ m 0 50 100 150 200 250 300 350 400 450 500 1 − 10 1 EWP analysis (13 TeV) -1 77.5 fb CMS 1 0 χ∼ bH → 2 0 χ∼ b → b~ , b~ b~ → pp theory 1 s.d. ± Observed experiment 1 s.d. ± Expected 95% CL upper limit on cross section [pb] [GeV] 0 2 χ∼ = m ± 1 χ∼ m 140 160 180 200 220 240 260 280 300 [GeV] 0 1 χ∼ m 0 20 40 60 80 100 120 140 160 180 200 1 − 10 1 (13 TeV) -1 77.5 fb CMS 0 1 χ∼ H → 0 2 χ∼ , 0 1 χ∼ ± W → ± 1 χ∼ , 0 2 χ∼ ± 1 χ∼ → pp theory 1 s.d. ± Observed experiment 1 s.d. ± Expected 95% CL upper limit on cross section [pb] SP Analysis e observed 95% CL upper limits on the bottom squark pair production lysis (upper plot), and on the wino-like chargino-neutralino product alysis (lower plot), are shown. The bold and light solid black contou usion region and the ±1 standard deviation (s.d.) band, including bo al uncertainties. The analogous red dotted contours represent the ex ±1 s.d. band. 250 300 350 400 450 500 550 600 650 700 [GeV] 0 1 χ∼ m 0 50 100 150 200 250 300 350 400 450 500 1 − 10 1 EWP analysis (13 TeV) -1 77.5 fb CMS 1 0 χ∼ bH → 2 0 χ∼ b → b~ , b~ b~ → pp theory 1 s.d. ± Observed experiment 1 s.d. A Additional simplified model interpretations While the EWP and SP analyses have greater expected sensitivity to electroweak and strong SUSY production, respectively, both analyses do have sensitivity to both production modes. In this appendix, we present limits obtained from the EWP and SP analyses for the simplified models that were not shown in section 8. The upper plot of figure 6 shows the limits for sbottom pair production obtained using the EWP analysis, as a function of the bottom squark mass and the LSP mass. For the wino-like chargino-neutralino production, the limits obtained using the SP analysis are shown in the lower plot of figure 6 as a function of the chargino mass and the LSP mass. Figure 7 shows the limits for the higgsino-like chargino-neutralino production simplified models obtained using the SP analysis as a function of the chargino mass for the case where the branching fraction of the eχ0 1 →HeG decay is 100% on the left, and for the case where the branching fraction of the eχ0 1 →HeG and eχ0 1 →ZeG decays are both 50% on the right. – 24 – [GeV] b~ m 250 300 350 400 450 500 550 600 650 700 [GeV] 0 1 χ∼ m 0 50 100 150 200 250 300 350 400 450 500 1 − 10 1 EWP analysis (13 TeV) -1 77.5 fb CMS 1 0 χ∼ bH → 2 0 χ∼ b → b~ , b~ b~ → pp theory 1 s.d. ± Observed experiment 1 s.d. ± Expected 95% CL upper limit on cross section [pb] [GeV] 0 2 χ∼ = m ± 1 χ∼ m 140 160 180 200 220 240 260 280 300 [GeV] 0 1 χ∼ m 0 20 40 60 80 100 120 140 160 180 200 1 − 10 1 (13 TeV) -1 77.5 fb CMS 0 1 χ∼ H → 0 2 χ∼ , 0 1 χ∼ ± W → ± 1 χ∼ , 0 2 χ∼ ± 1 χ∼ → pp theory 1 s.d. ± Observed experiment 1 s.d. ± Expected 95% CL upper limit on cross section [pb] SP Analysis re 6. The observed 95% CL upper limits on the bottom squark pair production cross section for WP analysis (upper plot), and on the wino-like chargino-neutralino production cross section e SP analysis (lower plot), are shown. A Additional simplified model interpretations ± Expected 95% CL upper limit on cross section [pb] JHEP11(2019)109 [GeV] 0 2 χ∼ = m ± 1 χ∼ m 140 160 180 200 220 240 260 280 300 [GeV] 0 1 χ∼ m 0 20 40 60 80 100 120 140 160 180 200 1 − 10 1 (13 TeV) -1 77.5 fb CMS 0 1 χ∼ H → 0 2 χ∼ , 0 1 χ∼ ± W → ± 1 χ∼ , 0 2 χ∼ ± 1 χ∼ → pp theory 1 s.d. ± Observed experiment 1 s.d. ± Expected 95% CL upper limit on cross section [pb] SP Analysis Figure 6. The observed 95% CL upper limits on the bottom squark pair production cross section for the EWP analysis (upper plot), and on the wino-like chargino-neutralino production cross section for the SP analysis (lower plot), are shown. The bold and light solid black contours represent the observed exclusion region and the ±1 standard deviation (s.d.) band, including both experimental and theoretical uncertainties. The analogous red dotted contours represent the expected exclusion region and its ±1 s.d. band. – 25 – [GeV] 1 0 χ∼ Higgsino mass m 150 200 250 300 350 400 450 [pb] excl 95% σ 1 − 10 1 10 2 10 3 10 (100%) G~ H → 1 0 χ∼ ; soft + X 1 0 χ∼ 1 0 χ∼ → j ± 0, χ∼ i ± 0, χ∼ → pp 1 0 χ∼ m ≈ 1 ± χ∼ m ≈ 2 0 χ∼ = 1 GeV; m G~ m (13 TeV) -1 77.5 fb CMS NLO+NLL theory Observed limit (95% CL) Median expected limit 68% expected 95% expected SP analysis [GeV] 1 0 χ∼ Higgsino mass m 150 200 250 300 350 400 450 [pb] excl 95% σ 1 − 10 1 10 2 10 3 10 (50%) G~ H → 1 0 χ∼ ; soft + X 1 0 χ∼ 1 0 χ∼ → j ± 0, χ∼ i ± 0, χ∼ → pp (50%) G~ Z → 1 0 χ∼ 1 0 χ∼ m ≈ 1 ± χ∼ m ≈ 2 0 χ∼ = 1 GeV; m G~ m (13 TeV) -1 77.5 fb CMS NLO+NLL theory Observed limit (95% CL) Median expected limit 68% expected 95% expected SP analysis Figure 7. A Additional simplified model interpretations The observed 95% CL upper limits on the production cross section for higgsino-like chargino-neutralino production are shown for the SP analysis. The charginos and neutralinos un- dergo several cascade decays producing either Higgs bosons (left plot), or a Higgs boson and a Z boson (right plot). We present limits in the scenario where the branching fraction of eχ0 1 →HeG decay is 100% (left plot), and where the eχ0 1 →HeG and eχ0 1 →ZeG decays are each 50% (right plot). The dotted and solid black curves represent the expected and observed exclusion region, and the green dark and yellow light bands represent the ±1 and ±2 standard deviation regions, respectively. The red solid and dotted lines show the theoretical production cross section and its uncertainty band. [GeV] 1 0 χ∼ Higgsino mass m 150 200 250 300 350 400 450 [pb] excl 95% σ 1 − 10 1 10 2 10 3 10 (50%) G~ H → 1 0 χ∼ ; soft + X 1 0 χ∼ 1 0 χ∼ → j ± 0, χ∼ i ± 0, χ∼ → pp (50%) G~ Z → 1 0 χ∼ 1 0 χ∼ m ≈ 1 ± χ∼ m ≈ 2 0 χ∼ = 1 GeV; m G~ m (13 TeV) -1 77.5 fb CMS NLO+NLL theory Observed limit (95% CL) Median expected limit 68% expected 95% expected SP analysis [GeV] 1 0 χ∼ Higgsino mass m 150 200 250 300 350 400 450 [pb] excl 95% σ 1 − 10 1 10 2 10 3 10 (100%) G~ H → 1 0 χ∼ ; soft + X 1 0 χ∼ 1 0 χ∼ → j ± 0, χ∼ i ± 0, χ∼ → pp 1 0 χ∼ m ≈ 1 ± χ∼ m ≈ 2 0 χ∼ = 1 GeV; m G~ m (13 TeV) -1 77.5 fb CMS NLO+NLL theory Observed limit (95% CL) Median expected limit 68% expected 95% expected SP analysis JHEP11(2019)109 Figure 7. The observed 95% CL upper limits on the production cross section for higgsino-like chargino-neutralino production are shown for the SP analysis. The charginos and neutralinos un- dergo several cascade decays producing either Higgs bosons (left plot), or a Higgs boson and a Z boson (right plot). A Additional simplified model interpretations We present limits in the scenario where the branching fraction of eχ0 1 →HeG decay is 100% (left plot), and where the eχ0 1 →HeG and eχ0 1 →ZeG decays are each 50% (right plot). The dotted and solid black curves represent the expected and observed exclusion region, and the green dark and yellow light bands represent the ±1 and ±2 standard deviation regions, respectively. The red solid and dotted lines show the theoretical production cross section and its uncertainty band. Open Access. This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited. References [1] M. Monaco, M. Pierini, A. Romanino and M. Spinrath, Phenomenology of minimal unified tree level gauge mediation at the LHC, JHEP 07 (2013) 078 [arXiv:1302.1305] [INSPIRE]. [2] J. Duarte, C. Pe˜na, A. Wang, M. Pierini and M. Spiropulu, Squark-mediated Higgs+jets production at the LHC, arXiv:1703.06544 [INSPIRE]. [3] S. Dimopoulos and H. Georgi, Softly broken supersymmetry and SU(5), Nucl. Phys. B 193 (1981) 150 [INSPIRE]. [4] S. Dimopoulos, M. Dine, S. Raby and S.D. Thomas, Experimental signatures of low-energy gauge mediated supersymmetry breaking, Phys. Rev. Lett. 76 (1996) 3494 [hep-ph/9601367] [INSPIRE]. [5] K.T. Matchev and S.D. Thomas, Higgs and Z boson signatures of supersymmetry, Phys. Rev. D 62 (2000) 077702 [hep-ph/9908482] [INSPIRE]. [6] ATLAS collaboration, Search for direct pair production of a chargino and a neutralino decaying to the 125 GeV Higgs boson in √s = 8 TeV pp collisions with the ATLAS detector, Eur. Phys. J. C 75 (2015) 208 [arXiv:1501.07110] [INSPIRE]. [7] CMS collaboration, Searches for electroweak neutralino and chargino production in channels with Higgs, Z and W bosons in pp collisions at 8 TeV, Phys. Rev. D 90 (2014) 092007 [arXiv:1409.3168] [INSPIRE]. – 26 – [8] CMS collaboration, Search for supersymmetry with Higgs boson to diphoton decays using the razor variables at √s = 13 TeV, Phys. Lett. B 779 (2018) 166 [arXiv:1709.00384] [INSPIRE]. [9] ATLAS collaboration, Search for chargino and neutralino production in final states with a Higgs boson and missing transverse momentum at √s = 13 TeV with the ATLAS detector, Phys. Rev. D 100 (2019) 012006 [arXiv:1812.09432] [INSPIRE]. [10] ATLAS collaboration, Search for bottom-squark pair production with the ATLAS detector in final states containing Higgs bosons, b-jets and missing transverse momentum, arXiv:1908.03122 [INSPIRE]. [11] ATLAS collaboration, Search for pair production of higgsinos in final statesv with at least three b-tagged jets in √s = 13 TeV pp collisions using the ATLAS detector, Phys. Rev. D 98 (2018) 092002 [arXiv:1806.04030] [INSPIRE]. JHEP11(2019)109 [12] CMS collaboration, The CMS trigger system, 2017 JINST 12 P01020 [arXiv:1609.02366] [INSPIRE]. [13] CMS collaboration, The CMS experiment at the CERN LHC, 2008 JINST 3 S08004 [INSPIRE]. [14] J. Alwall et al., The automated computation of tree-level and next-to-leading order differential cross sections and their matching to parton shower simulations, JHEP 07 (2014) 079 [arXiv:1405.0301] [INSPIRE]. References [15] ATLAS and CMS collaborations, Combined measurement of the Higgs boson mass in pp collisions at √s = 7 and 8 TeV with the ATLAS and CMS experiments, Phys. Rev. Lett. 114 (2015) 191803 [arXiv:1503.07589] [INSPIRE]. [16] CMS collaboration, Measurements of properties of the Higgs boson decaying into the four-lepton final state in pp collisions at √s = 13 TeV, JHEP 11 (2017) 047 [arXiv:1706.09936] [INSPIRE]. [17] LHC Higgs Cross Section Working Group collaboration, Handbook of LHC Higgs cross sections: 4. Deciphering the nature of the Higgs sector, arXiv:1610.07922 [INSPIRE]. [18] R. Frederix and S. Frixione, Merging meets matching in MC@NLO, JHEP 12 (2012) 061 [arXiv:1209.6215] [INSPIRE]. [19] J. Alwall et al., Comparative study of various algorithms for the merging of parton showers and matrix elements in hadronic collisions, Eur. Phys. J. C 53 (2008) 473 [arXiv:0706.2569] [INSPIRE]. [20] T. Sj¨ostrand et al., An introduction to PYTHIA 8.2, Comput. Phys. Commun. 191 (2015) 159 [arXiv:1410.3012] [INSPIRE]. [21] P. Skands, S. Carrazza and J. Rojo, Tuning PYTHIA 8.1: the Monash 2013 Tune, Eur. Phys. J. C 74 (2014) 3024 [arXiv:1404.5630] [INSPIRE]. [22] CMS collaboration, Extraction and validation of a new set of CMS PYTHIA8 tunes from underlying-event measurements, arXiv:1903.12179 [INSPIRE]. [23] NNPDF collaboration, Parton distributions for the LHC Run II, JHEP 04 (2015) 040 [arXiv:1410.8849] [INSPIRE]. [24] NNPDF collaboration, Parton distributions from high-precision collider data, Eur. Phys. J. C 77 (2017) 663 [arXiv:1706.00428] [INSPIRE]. – 27 – [25] W. Beenakker, R. H¨opker, M. Spira and P.M. Zerwas, Squark and gluino production at hadron colliders, Nucl. Phys. B 492 (1997) 51 [hep-ph/9610490] [INSPIRE]. [26] A. Kulesza and L. Motyka, Threshold resummation for squark-antisquark and gluino-pair production at the LHC, Phys. Rev. Lett. 102 (2009) 111802 [arXiv:0807.2405] [INSPIRE]. [27] A. Kulesza and L. Motyka, Soft gluon resummation for the production of gluino-gluino and squark-antisquark pairs at the LHC, Phys. Rev. D 80 (2009) 095004 [arXiv:0905.4749] [INSPIRE]. [28] W. Beenakker, S. Brensing, M. Kr¨amer, A. Kulesza, E. Laenen and I. Niessen, Soft-gluon resummation for squark and gluino hadroproduction, JHEP 12 (2009) 041 [arXiv:0909.4418] [INSPIRE]. JHEP11(2019)109 [29] W. Beenakker et al., Squark and gluino hadroproduction, Int. J. Mod. Phys. A 26 (2011) 2637 [arXiv:1105.1110] [INSPIRE]. [30] C. Borschensky et al., Squark and gluino production cross sections in pp collisions at √s = 13, 14, 33 and 100 TeV, Eur. Phys. J. C 74 (2014) 3174 [arXiv:1407.5066] [INSPIRE] [31] W. Beenakker, M. Klasen, M. Kr¨amer, T. References Plehn, M. Spira and P.M. Zerwas, The Production of charginos/neutralinos and sleptons at hadron colliders, Phys. Rev. Lett. 83 (1999) 3780 [Erratum ibid. 100 (2008) 029901] [hep-ph/9906298] [INSPIRE]. [32] B. Fuks, M. Klasen, D.R. Lamprea and M. Rothering, Gaugino production in proton-proton collisions at a center-of-mass energy of 8 TeV, JHEP 10 (2012) 081 [arXiv:1207.2159] [INSPIRE]. [33] B. Fuks, M. Klasen, D.R. Lamprea and M. Rothering, Precision predictions for electroweak superpartner production at hadron colliders with Resummino, Eur. Phys. J. C 73 (2013) 2480 [arXiv:1304.0790] [INSPIRE]. [34] P.Z. Skands et al., SUSY Les Houches accord: Interfacing SUSY spectrum calculators, decay packages and event generators, JHEP 07 (2004) 036 [hep-ph/0311123] [INSPIRE]. [35] GEANT4 collaboration, GEANT4: a simulation toolkit, Nucl. Instrum. Meth. A 506 (2003) 250 [INSPIRE]. [36] CMS collaboration, The fast simulation of the CMS detector at LHC, J. Phys. Conf. Ser. 331 (2011) 032049 [INSPIRE]. [37] A. Giammanco, The fast simulation of the CMS experiment, J. Phys. Conf. Ser. 513 (2014) 022012 [INSPIRE]. [38] CMS collaboration, Search for top-squark pair production in the single-lepton final state in pp collisions at √s = 8 TeV, Eur. Phys. J. C 73 (2013) 2677 [arXiv:1308.1586] [INSPIRE]. [39] CMS collaboration, Particle-flow reconstruction and global event description with the CMS detector, 2017 JINST 12 P10003 [arXiv:1706.04965] [INSPIRE]. [40] M. Cacciari, G.P. Salam and G. Soyez, The anti-kt jet clustering algorithm, JHEP 04 (2008) 063 [arXiv:0802.1189] [INSPIRE]. [41] M. Cacciari, G.P. Salam and G. Soyez, FastJet user manual, Eur. Phys. J. C 72 (2012) 1896 [arXiv:1111.6097] [INSPIRE]. [42] CMS collaboration, Performance of photon reconstruction and identification with the CMS detector in proton-proton collisions at √s = 8 TeV, 2015 JINST 10 P08010 [arXiv:1502.02702] [INSPIRE]. [43] M. Cacciari and G.P. Salam, Pileup subtraction using jet areas, Phys. Lett. B 659 (2008) 119 [arXiv:0707.1378] [INSPIRE]. – 28 – [44] CMS collaboration, Jet energy scale and resolution in the CMS experiment in pp collisions at 8 TeV, 2017 JINST 12 P02014 [arXiv:1607.03663] [INSPIRE]. [45] CMS collaboration, Identification of b-Quark Jets with the CMS Experiment, 2013 JINST 8 P04013 [arXiv:1211.4462] [INSPIRE]. [46] CMS collaboration, Missing transverse energy performance of the CMS detector, 2011 JINST 6 P09001 [arXiv:1106.5048] [INSPIRE]. [47] C. Rogan, Kinematical variables towards new dynamics at the LHC, arXiv:1006.2727 [INSPIRE]. [48] CMS collaboration, Inclusive search for supersymmetry using razor variables in pp collisions at √s = 13 TeV, Phys. Rev. D 95 (2017) 012003 [arXiv:1609.07658] [INSPIRE]. References JHEP11(2019)109 [49] CMS collaboration, Search for new physics with the MT 2 variable in all-jets final states produced in pp collisions at √s = 13 TeV, JHEP 10 (2016) 006 [arXiv:1603.04053] [INSPIRE]. [50] C.G. Lester and D.J. Summers, Measuring masses of semiinvisibly decaying particles pair produced at hadron colliders, Phys. Lett. B 463 (1999) 99 [hep-ph/9906349] [INSPIRE]. [51] H. Akaike, A new look at the statistical model identification, IEEE Trans. Automat. Control 19 (1974) 716. [52] P.D. Dauncey, M. Kenzie, N. Wardle and G.J. Davies, Handling uncertainties in background shapes, 2015 JINST 10 P04015 [arXiv:1408.6865] [INSPIRE]. [53] CMS collaboration, Observation of the diphoton decay of the Higgs boson and measurement of its properties, Eur. Phys. J. C 74 (2014) 3076 [arXiv:1407.0558] [INSPIRE]. [54] M.J. Oreglia, A study of the reactions ψ′ →γγψ, Ph.D. Thesis, Stanford University, Stanford U.S.A. (1980), SLAC Report SLAC-R-236, http://www.slac.stanford.edu/pubs/slacreports/slac-r-236.html. [55] J. Gaiser, Charmonium Spectroscopy From Radiative Decays of the J/ψ and ψ′, Ph.D. Thesis, SLAC, Menlo Park U.S.A. (1982), http://www-public.slac.stanford.edu/sciDoc/docMeta.aspx?slacPubNumber=slac-r-255.html. [56] A. Kalogeropoulos and J. Alwall, The SysCalc code: A tool to derive theoretical systematic uncertainties, arXiv:1801.08401 [INSPIRE]. [57] J. Butterworth et al., PDF4LHC recommendations for LHC Run II, J. Phys. G 43 (2016) 023001 [arXiv:1510.03865] [INSPIRE]. [58] T. Junk, Confidence level computation for combining searches with small statistics, Nucl. Instrum. Meth. A 434 (1999) 435 [hep-ex/9902006] [INSPIRE]. [59] A.L. Read, Presentation of search results: The CLs technique, J. Phys. G 28 (2002) 2693 [INSPIRE]. [60] ATLAS, CMS collaborations and The LHC Higgs Combination Group, Procedure for the LHC Higgs boson search combination in Summer 2011, ATL-PHYS-PUB-2011-011 (2011). [61] G. Cowan, K. Cranmer, E. Gross and O. Vitells, Asymptotic formulae for likelihood-based tests of new physics, Eur. Phys. J. C 71 (2011) 1554 [Erratum ibid. C 73 (2013) 2501] [arXiv:1007.1727] [INSPIRE]. – 29 – Yerevan Physics Institute, Yerevan, Armenia A.M. Sirunyan†, A. Tumasyan Institut f¨ur Hochenergiephysik, Wien, Austria W. Adam, F. Ambrogi, T. Bergauer, J. Brandstetter, M. Dragicevic, J. Er¨o, A. Es- calante Del Valle, M. Flechl, R. Fr¨uhwirth1, M. Jeitler1, N. Krammer, I. Kr¨atschmer, D. Liko, T. Madlener, I. Mikulec, N. Rad, J. Schieck1, R. Sch¨ofbeck, M. Spanring, D. Spitzbart, W. Waltenberger, C.-E. Wulz1, M. Zarucki JHEP11(2019)109 Institute for Nuclear Problems, Minsk, Belarus V. Drugakov, V. Mossolov, J. Suarez Gonzalez Institute for Nuclear Problems, Minsk, Belarus V. Drugakov, V. Mossolov, J. Suarez Gonzalez Universiteit Antwerpen, Antwerpen, Belgium M.R. Darwish, E.A. De Wolf, D. Di Croce, X. Janssen, A. Lelek, M. Pieters, H. Rejeb Sfar, H. Van Haevermaet, P. Van Mechelen, S. Van Putte, N. Van Remortel Vrije Universiteit Brussel, Brussel, Belgium Vrije Universiteit Brussel, Brussel, Belgium F. Blekman, E.S. Bols, S.S. Chhibra, J. D’Hondt, J. De Clercq, D. Lontkovskyi, S. Lowett F. Blekman, E.S. Bols, S.S. Chhibra, J. D’Hondt, J. De Clercq, D. Lontkovskyi, S. Lowette, I. Marchesini, S. Moortgat, Q. Python, K. Skovpen, S. Tavernier, W. Van Doninck, P. Van Mulders P. Van Mulders Universit´e Libre de Bruxelles, Bruxelles, Belgium The CMS collaboration The CMS collaboration Yerevan Physics Institute, Yerevan, Armenia A.M. Sirunyan†, A. Tumasyan Universit´e Libre de Bruxelles, Bruxelles, Belgium D. Beghin, B. Bilin, H. Brun, B. Clerbaux, G. De Lentdecker, H. Delannoy, B. Dorne D. Beghin, B. Bilin, H. Brun, B. Clerbaux, G. De Lentdecker, H. Delannoy, B. Dorney, L. Favart, A. Grebenyuk, A.K. Kalsi, A. Popov, N. Postiau, E. Starling, L. Thomas, C. Vander Velde, P. Vanlaer, D. Vannerom Ghent University, Ghent, Belgium Ghent University, Ghent, Belgium T. Cornelis, D. Dobur, I. Khvastunov2, M. Niedziela, C. Roskas, D. Trocino, M. Tytgat, W. Verbeke, B. Vermassen, M. Vit, N. Zaganidis Universit´e Catholique de Louvain, Louvain-la-Neuve, Belgium q , , g O. Bondu, G. Bruno, C. Caputo, P. David, C. Delaere, M. Delcourt, A. Giammanco, V. Lemaitre, A. Magitteri, J. Prisciandaro, A. Saggio, M. Vidal Marono, P. Vischia, J. Zobec Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, Brazil F.L. Alves, G.A. Alves, G. Correia Silva, C. Hensel, A. Moraes, P. Rebello Teles Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil E. Belchior Batista Das Chagas, W. Carvalho, J. Chinellato3, E. Coelho, E.M. Da Costa, G.G. Da Silveira4, D. De Jesus Damiao, C. De Oliveira Martins, S. Fonseca De Souza, L.M. Huertas Guativa, H. Malbouisson, J. Martins5, D. Matos Figueiredo, M. Med- ina Jaime6, M. Melo De Almeida, C. Mora Herrera, L. Mundim, H. Nogima, W.L. Prado Da Silva, L.J. Sanchez Rosas, A. Santoro, A. Sznajder, M. Thiel, E.J. Tonelli Manganote3, F. Torres Da Silva De Araujo, A. Vilela Pereira – 30 – Universidade Estadual Paulista a, Universidade Federal do ABC b, S˜ao Paulo, Brazil C.A. Bernardesa, L. Calligarisa, T.R. Fernandez Perez Tomeia, E.M. Gregoresb, D.S. Lemos, P.G. Mercadanteb, S.F. Novaesa, SandraS. Padulaa Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia, Bulgaria A. Aleksandrov, G. Antchev, R. Hadjiiska, P. Iaydjiev, M. Misheva, M. Rodozov, M. Shopova, G. Sultanov University of Sofia, Sofia, Bulgaria M. Bonchev, A. Dimitrov, T. Ivanov, L. Litov, B. Pavlov, P. Petkov JHEP11(2019)109 University of Sofia, Sofia, Bulgaria University of Sofia, Sofia, Bulgaria M. Bonchev, A. Dimitrov, T. Ivanov, L. Litov, B. Pavlov, P. Petkov Beihang University, Beijing, China W. Fang7, X. Gao7, L. Yuan Beihang University, Beijing, China W. Fang7, X. Gao7, L. Yuan Beihang University, Beijing, China Institute of High Energy Physics, Beijing, China M. Ahmad, G.M. Chen, H.S. Chen, M. Chen, C.H. Jiang, D. Leggat, H. Liao, Z. Li . Ahmad, G.M. Chen, H.S. Chen, M. Chen, C.H. Jiang, D. Leggat, H. Liao, Z. Liu, M Shaheen8 A Spiezia J Tao E Yazgan H Zhang S Zhang8 J Zhao M. Ahmad, G.M. Chen, H.S. Chen, M. Chen, C.H. Jiang, D. Leggat, H. Liao, Z. Liu, S.M. Shaheen8, A. Spiezia, J. Tao, E. Yazgan, H. Zhang, S. Zhang8, J. Zhao State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing, China A. Agapitos, Y. Ban, G. Chen, A. Levin, J. Li, L. Li, Q. Li, Y. Mao, S.J. Qian, D. Wang, Q. Wang Tsinghua University, Beijing, China Z. Hu, Y. Wang Tsinghua University, Beijing, China Z. Hu, Y. Wang Zhejiang University - Department of Physics M. Xiao Universidad de Los Andes, Bogota, Colombia C. Avila, A. Cabrera, C. Florez, C.F. Gonz´alez Hern´andez, M.A. Segura Delgado , g , C. Avila, A. Cabrera, C. Florez, C.F. Gonz´alez Hern´andez, M.A. Segura Delgado Universidad de Antioquia, Medellin, Colombia J. Mejia Guisao, J.D. Ruiz Alvarez, C.A. Salazar Gonz´alez, N. Vanegas Arbelaez Universidad de Antioquia, Medellin, Colombia J Mejia Guisao J D Ruiz Alvarez C A Salazar Gonz´alez N Vanegas Arbelaez q , , J. Mejia Guisao, J.D. Ruiz Alvarez, C.A. Salazar Gonz´alez, N. Vanegas Arbelaez University of Split, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, Split, Croatia D. Giljanovi´c, N. Godinovic, D. Lelas, I. Puljak, T. Sculac University of Split, Faculty of Science, Split, Croatia Z. Antunovic, M. Kovac Institute Rudjer Boskovic, Zagreb, Croatia V Brigljevic S Ceci D Ferencek K Kadija B Mesic M Roguljic A Starodumov9 Institute Rudjer Boskovic, Zagreb, Croatia Universidad San Francisco de Quito, Quito, Ecuador E. Carrera Jarrin Universidad San Francisco de Quito, Quito, Ecuador E. Carrera Jarrin Academy of Scientific Research and Technology of the Arab Republic of Egypt, Egyptian Network of High Energy Physics, Cairo, Egypt S. Abu Zeid11, S. Khalil12 National Institute of Chemical Physics and Biophysics, Tallinn, Estonia National Institute of Chemical Physics and Biophysics, Tallinn, Estonia S. Bhowmik, A. Carvalho Antunes De Oliveira, R.K. Dewanjee, K. Ehataht, M. Kadastik, M. Raidal, C. Veelken S. Bhowmik, A. Carvalho Antunes De Oliveira, R.K. Dewanjee, K. Ehataht, M. Kadasti M. Raidal, C. Veelken Department of Physics, University of Helsinki, Helsinki, Finland P. Eerola, L. Forthomme, H. Kirschenmann, K. Osterberg, M. Voutilainen Helsinki Institute of Physics, Helsinki, Finland Helsinki Institute of Physics, Helsinki, Finland F. Garcia, J. Havukainen, J.K. Heikkil¨a, T. J¨arvinen, V. Karim¨aki, M.S. Kim, R. Kinnunen, T Lamp´en K Lassila-Perini S Laurila S Lehti T Lind´en P Luukka T M¨aenp¨a¨a F. Garcia, J. Havukainen, J.K. Heikkil¨a, T. J¨arvinen, V. Karim¨aki, M.S. Kim, R. Kinnunen, T. Lamp´en, K. Lassila-Perini, S. Laurila, S. Lehti, T. Lind´en, P. Luukka, T. M¨aenp¨a¨a, H Siikonen E Tuominen J Tuominiemi F. Garcia, J. Havukainen, J.K. Heikkil¨a, T. J¨arvinen, V. Karim¨aki, M.S. Kim, R. Kinnune F. Garcia, J. Havukainen, J.K. Heikkila, T. Jarvinen, V. Karimaki, M.S. Kim, R. Kinnunen, T. Lamp´en, K. Lassila-Perini, S. Laurila, S. Lehti, T. Lind´en, P. Luukka, T. M¨aenp¨a¨a, H. Siikonen, E. Tuominen, J. Tuominiemi Lappeenranta University of Technology, Lappeenranta, Finland T. Tuuva IRFU, CEA, Universit´e Paris-Saclay, Gif-sur-Yvette, France M. Besancon, F. Couderc, M. Dejardin, D. Denegri, B. Fabbro, J.L. Faure, F. Ferri, S. Ganjour, A. Givernaud, P. Gras, G. Hamel de Monchenault, P. Jarry, C. Leloup, E. Locci, J. Malcles, J. Rander, A. Rosowsky, M. ¨O. Sahin, A. Savoy-Navarro13, M. Titov Laboratoire Leprince-Ringuet, Ecole polytechnique, CNRS/IN2P3, Universit´e Paris-Saclay, Palaiseau, France S. Ahuja, C. Amendola, F. Beaudette, P. Busson, C. Charlot, B. Diab, G. Falmagn S. Ahuja, C. Amendola, F. Beaudette, P. Busson, C. Charlot, B. Diab, G. Falmagne, R. Granier de Cassagnac, I. Kucher, A. Lobanov, C. Martin Perez, M. Nguyen, C. Ochando, P. Paganini, J. Rembser, R. Salerno, J.B. Sauvan, Y. Sirois, A. Zabi, A. Zghiche S. Ahuja, C. Amendola, F. Beaudette, P. Busson, C. Charlot, B. Diab, G. Falmagne, R. Granier de Cassagnac, I. Kucher, A. Lobanov, C. Martin Perez, M. Nguyen, C. Ochando, R. Granier de Cassagnac, I. Kucher, A. Lobanov, C. Martin Perez, M. Nguyen, C. Ochando, P. Paganini, J. Rembser, R. Salerno, J.B. Sauvan, Y. Sirois, A. Zabi, A. Zghiche P. Paganini, J. Rembser, R. Salerno, J.B. Sauvan, Y. Sirois, A. Zabi, A. Zghiche Universit´e de Strasbourg, CNRS, IPHC UMR 7178, Strasbourg, France J.-L. Agram14, J. Andrea, D. Bloch, G. Bourgatte, J.-M. Brom, E.C. Chabert, C. Collard, E. Conte14, J.-C. Fontaine14, D. Gel´e, U. Goerlach, M. Jansov´a, A.-C. Le Bihan, N. Tonon, P. Van Hove Universit´e de Strasbourg, CNRS, IPHC UMR 7178, Strasbourg, France J.-L. Agram14, J. Andrea, D. Bloch, G. Bourgatte, J.-M. Brom, E.C. Chabert, C. Collard, E Conte14 J -C Fontaine14 D Gel´e U Goerlach M Jansov´a A -C Le Bihan N Tonon J.-L. Agram14, J. Andrea, D. Bloch, G. Bourgatte, J.-M. Brom, E.C. Chabert, C. Institute Rudjer Boskovic, Zagreb, Croatia V. Brigljevic, S. Ceci, D. Ferencek, K. Kadija, B. Mesic, M. Roguljic, A. Starodumov9, T. Susa – 31 – University of Cyprus, Nicosia, Cyprus M.W. Ather, A. Attikis, E. Erodotou, A. Ioannou, M. Kolosova, S. Konstantinou, G. Mavromanolakis, J. Mousa, C. Nicolaou, F. Ptochos, P.A. Razis, H. Rykaczewski, D. Tsiakkouri Charles University, Prague, Czech Republic M. Finger10, M. Finger Jr.10, A. Kveton, J. Tomsa Escuela Politecnica Nacional, Quito, Ecuador E. Ayala JHEP11(2019)109 Helsinki Institute of Physics, Helsinki, Finland Collard, E. Conte14, J.-C. Fontaine14, D. Gel´e, U. Goerlach, M. Jansov´a, A.-C. Le Bihan, N. Tonon, P. Van Hove P. Van Hove P. Van Hove – 32 – Centre de Calcul de l’Institut National de Physique Nucleaire et de Physique des Particules, CNRS/IN2P3, Villeurbanne, France S. Gadrat Universit´e de Lyon, Universit´e Claude Bernard Lyon 1, CNRS-IN2P3, Institut de Physique Nucl´eaire de Lyon, Villeurbanne, France Universit´e de Lyon, Universit´e Claude Bernard Lyon 1, CNRS-IN2P3, Institut de Physique Nucl´eaire de Lyon, Villeurbanne, France S. Beauceron, C. Bernet, G. Boudoul, C. Camen, A. Carle, N. Chanon, R. Chierici, D. Contardo, P. Depasse, H. El Mamouni, J. Fay, S. Gascon, M. Gouzevitch, B. Ille, Sa. Jain, F. Lagarde, I.B. Laktineh, H. Lattaud, A. Lesauvage, M. Lethuillier, L. Mirabito, S P i V S di i L T t t t G T t M V d D kt S Vi t y q y , , S. Beauceron, C. Bernet, G. Boudoul, C. Camen, A. Carle, N. Chanon, R. Chierici, D. Contardo, P. Depasse, H. El Mamouni, J. Fay, S. Gascon, M. Gouzevitch, B. Ille, Sa. Jain, F. Lagarde, I.B. Laktineh, H. Lattaud, A. Lesauvage, M. Lethuillier, L. Mirabito, S. Perries, V. Sordini, L. Torterotot, G. Touquet, M. Vander Donckt, S. Viret JHEP11(2019)109 Georgian Technical University, Tbilisi, Georgia A. Khvedelidze10 Tbilisi State University, Tbilisi, Georgia Z. Tsamalaidze10 RWTH Aachen University, I. Physikalisches Institut, Aachen, Germany C. Autermann, L. Feld, M.K. Kiesel, K. Klein, M. Lipinski, D. Meuser, A. Pauls, M. Preuten, M.P. Rauch, C. Schomakers, J. Schulz, M. Teroerde, B. Wittmer RWTH Aachen University, III. Physikalisches Institut A, Aachen, Germany A. Albert, M. Erdmann, B. Fischer, S. Ghosh, T. Hebbeker, K. Hoepfner, H. Keller, L. Mas- trolorenzo, M. Merschmeyer, A. Meyer, P. Millet, G. Mocellin, S. Mondal, S. Mukherjee, D. Noll, A. Novak, T. Pook, A. Pozdnyakov, T. Quast, M. Radziej, Y. Rath, H. Reithler, J. Roemer, A. Schmidt, S.C. Schuler, A. Sharma, S. Wiedenbeck, S. Zaleski RWTH Aachen University, III. Physikalisches Institut A, Aachen, Germany A. Albert, M. Erdmann, B. Fischer, S. Ghosh, T. Hebbeker, K. Hoepfner, H. Keller, L. Mas- trolorenzo, M. Merschmeyer, A. Meyer, P. Millet, G. Mocellin, S. Mondal, S. Mukherjee, D. Noll, A. Novak, T. Pook, A. Pozdnyakov, T. Quast, M. Radziej, Y. Rath, H. Reithler, J. Roemer, A. Schmidt, S.C. Schuler, A. Sharma, S. Wiedenbeck, S. Zaleski RWTH Aachen University, III. Physikalisches Institut B, Aachen, Germany G. Helsinki Institute of Physics, Helsinki, Finland Fl¨ugge, W. Haj Ahmad15, O. Hlushchenko, T. Kress, T. M¨uller, A. Nehrkorn, A. Nowack, C. Pistone, O. Pooth, D. Roy, H. Sert, A. Stahl16 Deutsches Elektronen-Synchrotron, Hamburg, Germany Deutsches Elektronen-Synchrotron, Hamburg, Germany Deutsches Elektronen Synchrotron, Hamburg, Germany M. Aldaya Martin, P. Asmuss, I. Babounikau, H. Bakhshiansohi, K. Beernaert, O. Behnke, A. Berm´udez Mart´ınez, D. Bertsche, A.A. Bin Anuar, K. Borras17, V. Botta, A. Campbell, A. Cardini, P. Connor, S. Consuegra Rodr´ıguez, C. Contreras-Campana, V. Danilov, A. De Wit, M.M. Defranchis, C. Diez Pardos, D. Dom´ınguez Damiani, G. Eckerlin, D. Eck- stein, T. Eichhorn, A. Elwood, E. Eren, E. Gallo18, A. Geiser, A. Grohsjean, M. Guthoff, M. Haranko, A. Harb, A. Jafari, N.Z. Jomhari, H. Jung, A. Kasem17, M. Kasemann, H. Kaveh, J. Keaveney, C. Kleinwort, J. Knolle, D. Kr¨ucker, W. Lange, T. Lenz, J. Leonard, J. Lidrych, K. Lipka, W. Lohmann19, R. Mankel, I.-A. Melzer-Pellmann, A.B. Meyer, M. Meyer, M. Missiroli, G. Mittag, J. Mnich, A. Mussgiller, V. Myronenko, D. P´erez Ad´an, S.K. Pflitsch, D. Pitzl, A. Raspereza, A. Saibel, M. Savitskyi, V. Scheurer, P. Sch¨utze, C. Schwanenberger, R. Shevchenko, A. Singh, H. Tholen, O. Turkot, A. Vagnerini, M. Van De Klundert, R. Walsh, Y. Wen, K. Wichmann, C. Wissing, O. Zenaiev, R. Zlebcik University of Hamburg, Hamburg, Germany R. Aggleton, S. Bein, L. Benato, A. Benecke, V. Blobel, T. Dreyer, A. Ebrahimi, F. Feindt, University of Hamburg, Hamburg, Germany University of Hamburg, Hamburg, Germany R. Aggleton, S. Bein, L. Benato, A. Benecke, V. Blobel, T. Dreyer, A. Ebrahimi, F. Feindt, A. Fr¨ohlich, C. Garbers, E. Garutti, D. Gonzalez, P. Gunnellini, J. Haller, A. Hinzmann, – 33 – A. Karavdina, G. Kasieczka, R. Klanner, R. Kogler, N. Kovalchuk, S. Kurz, V. Kutzner, J. Lange, T. Lange, A. Malara, J. Multhaup, C.E.N. Niemeyer, A. Perieanu, A. Reimers, O. Rieger, C. Scharf, P. Schleper, S. Schumann, J. Schwandt, J. Sonneveld, H. Stadie, G. Steinbr¨uck, F.M. Stober, M. St¨over, B. Vormwald, I. Zoi A. Karavdina, G. Kasieczka, R. Klanner, R. Kogler, N. Kovalchuk, S. Kurz, V. Kutzne J. Lange, T. Lange, A. Malara, J. Multhaup, C.E.N. Niemeyer, A. Perieanu, A. Reimer J. Lange, T. Lange, A. Malara, J. Multhaup, C.E.N. Niemeyer, A. Perieanu, A. Reimers, O. Rieger, C. Scharf, P. Schleper, S. Schumann, J. Schwandt, J. Sonneveld, H. Stadie, G. Steinbr¨uck, F.M. Stober, M. St¨over, B. Vormwald, I. Zoi Karlsruher Institut fuer Technologie, Karlsruhe, Germany Karlsruher Institut fuer Technologie, Karlsruhe, Germany M. Akbiyik, C. Barth, M. Baselga, S. Baur, T. Berger, E. Butz, R. Caspart, T. Chwalek, W. De Boer, A. Dierlamm, K. El Morabit, N. Faltermann, M. Giffels, P. Goldenzweig, A. Gottmann, M.A. Harrendorf, F. Hartmann16, U. Husemann, S. Kudella, S. Mitra, M.U. Mozer, D. M¨uller, Th. M¨uller, M. Musich, A. N¨urnberg, G. Quast, K. Rabbertz, M. Schr¨oder, I. Shvetsov, H.J. Simonis, R. Ulrich, M. Wassmer, M. Weber, C. W¨ohrmann, R. Wolf JHEP11(2019)109 Institute of Nuclear and Particle Physics (INPP), NCSR Demokritos, Aghia Paraskevi, Greece Anagnostou, P. Asenov, G. Daskalakis, T. Geralis, A. Kyriakis, D. Loukas, G. Paspalaki National and Kapodistrian University of Athens, Athens, Greece M. Diamantopoulou, G. Karathanasis, P. Kontaxakis, A. Manousakis-katsikakis, A. Pana- giotou, I. Papavergou, N. Saoulidou, A. Stakia, K. Theofilatos, K. Vellidis, E. Vourliotis National Technical University of Athens, Athens, Greece G. Bakas, K. Kousouris, I. Papakrivopoulos, G. Tsipolitis University of Io´annina, Io´annina, Greece I. Evangelou, C. Foudas, P. Gianneios, P. Katsoulis, P. Kokkas, S. Mallios, K. Manitara, N. Manthos, I. Papadopoulos, J. Strologas, F.A. Triantis, D. Tsitsonis MTA-ELTE Lend¨ulet CMS Particle and Nuclear Physics Group, E¨otv¨os Lor´and University, Budapest, Hungary M. Bart´ok20, R. Chudasama, M. Csanad, P. Major, K. Mandal, A. Mehta, M.I. Nagy, G. Pasztor, O. Sur´anyi, G.I. Veres Wigner Research Centre for Physics, Budapest, Hungary G. Bencze, C. Hajdu, D. Horvath21, F. Sikler, T.´A. V´ami, V. Veszpremi, G. Vesztergombi† Institute of Nuclear Research ATOMKI, Debrecen, Hungary N. Beni, S. Czellar, J. Karancsi20, A. Makovec, J. Molnar, Z. Szillasi Institute of Nuclear Research ATOMKI, Debrecen, Hungary N. Beni, S. Czellar, J. Karancsi20, A. Makovec, J. Molnar, Z. Szillasi Institute of Physics, University of Debrecen, Debrecen, Hungary P. Raics, D. Teyssier, Z.L. Trocsanyi, B. Ujvari Eszterhazy Karoly University, Karoly Robert Campus, Gyongyos, Hungary T. Csorgo, W.J. Metzger, F. Nemes, T. Novak Indian Institute of Science (IISc), Bangalore, India S. Choudhury, J.R. Komaragiri, P.C. Tiwari Indian Institute of Science (IISc), Bangalore, India S. Choudhury, J.R. Komaragiri, P.C. Tiwari – 34 – National Institute of Science Education and Research, HBNI, Bhubaneswar, India National Institute of Science Education and Research, HBNI, Bhubaneswar, India S. Bahinipati23, C. Kar, G. Kole, P. Mal, V.K. Muraleedharan Nair Bindhu, A. Nayak24, D.K. Sahoo23, S.K. Swain Panjab University, Chandigarh, India Panjab University, Chandigarh, India S. Bansal, S.B. Beri, V. Bhatnagar, S. Chauhan, R. Chawla, N. Dhingra, R. Gupta, A. Kaur, M. Kaur, S. Kaur, P. Kumari, M. Lohan, M. Meena, K. Sandeep, S. Sharma, J.B. Singh, A.K. Virdi University of Delhi, Delhi, India JHEP11(2019)109 A. Bhardwaj, B.C. Choudhary, R.B. Garg, M. Gola, S. Keshri, Ashok Kumar, S. Malhotra, M Nai ddi P P i a ka K Ra ja Aasha Shah R Sha a A. Bhardwaj, B.C. Choudhary, R.B. Garg, M. Gola, S. Keshri, Ashok Kumar, S. Malhotra, M. Naimuddin, P. Priyanka, K. Ranjan, Aashaq Shah, R. Sharma j, y, g, , , , , . Naimuddin, P. Priyanka, K. Ranjan, Aashaq Shah, R. Sharma M. Naimuddin, P. Priyanka, K. Ranjan, Aashaq Shah, R. Sharma Saha Institute of Nuclear Physics, HBNI, Kolkata, India Saha Institute of Nuclear Physics, HBNI, Kolkata, India R. Bhardwaj25, M. Bharti25, R. Bhattacharya, S. Bhattacharya, U. Bhawandeep25, D. Bhowmik, S. Dutta, S. Ghosh, M. Maity26, K. Mondal, S. Nandan, A. Purohit, P.K. Rout, G. Saha, S. Sarkar, T. Sarkar26, M. Sharan, B. Singh25, S. Thakur25 Indian Institute of Technology Madras, Madras, India P.K. Behera, P. Kalbhor, A. Muhammad, P.R. Pujahari, A. Sharma, A.K. Sikdar Indian Institute of Technology Madras, Madras, India P.K. Behera, P. Kalbhor, A. Muhammad, P.R. Pujahari, A. Sharm Bhabha Atomic Research Centre, Mumbai, India D. Dutta, V. Jha, V. Kumar, D.K. Mishra, P.K. Netrakanti, L.M. Pant, P. Shukla Tata Institute of Fundamental Research-A, Mumbai, India T. Aziz, M.A. Bhat, S. Dugad, G.B. Mohanty, N. Sur, RavindraKumar Verma Tata Institute of Fundamental Research-B, Mumbai, India ata Institute of Fundamental Research-B, Mumbai, India S. Banerjee, S. Bhattacharya, S. Chatterjee, P. Das, M. Guchait, S. Karmakar, S. Kumar, G. Majumder, K. Mazumdar, N. Sahoo, S. Sawant Indian Institute of Science Education and Research (IISER), Pune, India Indian Institute of Science Education and Research (IISER), Pune, India S. Chauhan, S. Dube, V. Hegde, B. Kansal, A. Kapoor, K. Kothekar, S. Pandey, A. Rane, A. Rastogi, S. Sharma Institute for Research in Fundamental Sciences (IPM), Tehran, Iran S. Chenarani27, E. Eskandari Tadavani, S.M. Etesami27, M. Khakzad, M. Mohammadi Na- jafabadi, M. Naseri, F. Rezaei Hosseinabadi University College Dublin, Dublin, Ireland M. Felcini, M. Grunewald INFN Sezione di Bari a, Universit`a di Bari b, Politecnico di Bari c, Bari, Italy M. Abbresciaa,b, R. Alya,b,28, C. Calabriaa,b, A. Colaleoa, D. Creanzaa,c, L. Cristellaa,b, N. De Filippisa,c, M. De Palmaa,b, A. Di Florioa,b, L. Fiorea, A. Gelmia,b, G. Iasellia,c, M. Incea,b, S. Lezkia,b, G. Maggia,c, M. Maggia, G. Minielloa,b, S. Mya,b, S. Nuzzoa,b, A. Pompilia,b, G. Pugliesea,c, R. Radognaa, A. Ranieria, G. Selvaggia,b, L. Silvestrisa, R. Vendittia, P. Verwilligena R. Vendittia, P. Verwilligena – 35 – INFN Sezione di Bologna a, Universit`a di Bologna b, Bologna, Italy G. Abbiendia, C. Battilanaa,b, D. Bonacorsia,b, L. Borgonovia,b, S. Braibant-Giacomellia,b, R. Campaninia,b, P. Capiluppia,b, A. Castroa,b, F.R. Cavalloa, C. Cioccaa, G. Codispotia,b, M. Cuffiania,b, G.M. Dallavallea, F. Fabbria, A. Fanfania,b, E. Fontanesia,b, P. Giacomellia, C. Grandia, L. Guiduccia,b, F. Iemmia,b, S. Lo Meoa,29, S. Marcellinia, G. Masettia, F.L. Navarriaa,b, A. Perrottaa, F. Primaveraa,b, A.M. Rossia,b, T. Rovellia,b, G.P. Sirolia,b, N. Tosia INFN Sezione di Bologna a, Universit`a di Bologna b, Bologna, Italy G. Abbiendia, C. Battilanaa,b, D. Bonacorsia,b, L. Borgonovia,b, S. Braibant-Giacomellia R. Campaninia,b, P. Capiluppia,b, A. Castroa,b, F.R. Cavalloa, C. Cioccaa, G. Codispotia R. Campanini , P. Capiluppi , A. Castro , F.R. Cavallo , C. Ciocca , G. Codispoti , M. Cuffiania,b, G.M. Dallavallea, F. Fabbria, A. Fanfania,b, E. Fontanesia,b, P. Giacomellia, C. Grandia, L. Guiduccia,b, F. Iemmia,b, S. Lo Meoa,29, S. Marcellinia, G. Masettia, F.L. Navarriaa,b, A. Perrottaa, F. Primaveraa,b, A.M. Rossia,b, T. Rovellia,b, G.P. Sirolia,b, N. Tosia F.L. Navarriaa,b, A. Perrottaa, F. Primaveraa,b, A.M. Rossia,b, T. Rovellia,b, G.P. Sirolia,b, N. Tosia INFN Sezione di Catania a, Universit`a di Catania b, Catania, Italy S. Albergoa,b,30, S. Costaa,b, A. Di Mattiaa, R. Potenzaa,b, A. Tricomia,b,30, C. Tuvea,b JHEP11(2019)109 INFN Sezione di Firenze a, Universit`a di Firenze b, Firenze, Italy G. Barbaglia, A. Cassese, R. Ceccarelli, K. Chatterjeea,b, V. Ciullia,b, C. ata Institute of Fundamental Research-B, Mumbai, India Civininia, R. D’Alessandroa,b, E. Focardia,b, G. Latinoa,b, P. Lenzia,b, M. Meschinia, S. Paolettia, G. Sguazzonia, L. Viliania INFN Laboratori Nazionali di Frascati, Frascati, Italy L. Benussi, S. Bianco, D. Piccolo INFN Sezione di Genova a, Universit`a di Genova b, Genova, Italy M. Bozzoa,b, F. Ferroa, R. Mulargiaa,b, E. Robuttia, S. Tosia,b INFN Sezione di Milano-Bicocca a, Universit`a di Milano-Bicocca b, Milano, Italy A. Benagliaa, A. Beschia,b, F. Brivioa,b, V. Cirioloa,b,16, S. Di Guidaa,b,16, M.E. Dinardoa,b, P. Dinia, S. Gennaia, A. Ghezzia,b, P. Govonia,b, L. Guzzia,b, M. Malbertia, S. Malvezzia, D. Menascea, F. Montia,b, L. Moronia, M. Paganonia,b, D. Pedrinia, S. Ragazzia,b, A. Benagliaa, A. Beschia,b, F. Brivioa,b, V. Cirioloa,b,16, S. Di Guidaa,b,16, M.E. Dinardoa P. Dinia, S. Gennaia, A. Ghezzia,b, P. Govonia,b, L. Guzzia,b, M. Malbertia, S. Malvezzi A. Benagliaa, A. Beschia,b, F. Brivioa,b, V. Cirioloa,b, 6, S. Di Guidaa,b, 6, M.E. Dinardoa,b, P. Dinia, S. Gennaia, A. Ghezzia,b, P. Govonia,b, L. Guzzia,b, M. Malbertia, S. Malvezzia, D. Menascea, F. Montia,b, L. Moronia, M. Paganonia,b, D. Pedrinia, S. Ragazzia,b, T. Tabarelli de Fatisa,b, D. Zuoloa,b D. Menascea, F. Montia,b, L. Moronia, M. Paganonia,b, D. Pedrinia, S. Ragazzia,b, T. Tabarelli de Fatisa,b, D. Zuoloa,b INFN Sezione di Napoli a, Universit`a di Napoli ’Federico II’ b, Napoli, Italy, Universit`a della Basilicata c, Potenza, Italy, Universit`a G. Marconi d, Roma, Italy S. Buontempoa, N. Cavalloa,c, A. De Iorioa,b, A. Di Crescenzoa,b, F. Fabozzia,c, F. Fiengaa, G. Galatia, A.O.M. Iorioa,b, L. Listaa,b, S. Meolaa,d,16, P. Paoluccia,16, B. Rossia, C. Sciaccaa,b, E. Voevodinaa,b INFN Sezione di Padova a, Universit`a di Padova b, Padova, Italy, Universit`a di Trento c, Trento, Italy P. Azzia, N. Bacchettaa, D. Biselloa,b, A. Bolettia,b, A. Bragagnoloa,b, R. Carlina P. Azzia, N. Bacchettaa, D. Biselloa,b, A. Bolettia,b, A. Bragagnoloa,b, R. Carlina,b, P. Checchiaa, P. De Castro Manzanoa, T. Dorigoa, U. Dossellia, F. Gasparinia,b, U. Gasparinia,b, A. Gozzelinoa, S.Y. Hoha,b, P. Lujana, M. Margonia,b, A.T. Meneguzzoa,b, J. Pazzinia,b, M. Presillab, P. Ronchesea,b, R. Rossina,b, F. Simonettoa,b, A. Tikoa, M. Tosia,b, M. Zanettia,b, P. Zottoa,b, G. Zumerlea,b P. Checchia , P. De Castro Manzano , T. Dorigo , U. Dosselli , F. Gasparini , U. Gasparinia,b, A. Gozzelinoa, S.Y. Hoha,b, P. Lujana, M. Margonia,b, A.T. Meneguzzoa,b, J. Pazzinia,b, M. Presillab, P. Ronchesea,b, R. Rossina,b, F. Simonettoa,b, A. Tikoa, M. Tosia,b, M. Zanettia,b, P. Zottoa,b, G. Zumerlea,b INFN Sezione di Pavia a, Universit`a di Pavia b, Pavia, Italy A. Braghieria, D. Fiorinaa,b, P. Montagnaa,b, S.P. ata Institute of Fundamental Research-B, Mumbai, India Rattia,b, V. Rea, M. Ressegottia,b, INFN Sezione di Pavia a, Universit`a di Pavia b, Pavia, Italy A. Braghieria, D. Fiorinaa,b, P. Montagnaa,b, S.P. Rattia,b, V. Rea, M. Ressegottia,b, C. Riccardia,b, P. Salvinia, I. Vaia, P. Vituloa,b A. Braghieria, D. Fiorinaa,b, P. Montagnaa,b, S.P. Rattia,b, V. Rea, M. Ressegottia,b, C. Riccardia,b, P. Salvinia, I. Vaia, P. Vituloa,b – 36 – INFN Sezione di Perugia a, Universit`a di Perugia b, Perugia, Italy M. Biasinia,b, G.M. Bileia, D. Ciangottinia,b, L. Fan`oa,b, P. Laricciaa,b, R. Leonardia,b, G. Mantovania,b, V. Mariania,b, M. Menichellia, A. Rossia,b, A. Santocchiaa,b, D. Spigaa INFN Sezione di Perugia a, Universit`a di Perugia b, Perugia, Italy M. Biasinia,b, G.M. Bileia, D. Ciangottinia,b, L. Fan`oa,b, P. Laricciaa,b, R. Leonardia,b, G. Mantovania,b, V. Mariania,b, M. Menichellia, A. Rossia,b, A. Santocchiaa,b, D. Spigaa INFN Sezione di Perugia a, Universit`a di Perugia b, Perugia, Italy M. Biasinia,b, G.M. Bileia, D. Ciangottinia,b, L. Fan`oa,b, P. Laricciaa,b, R. Leonardia G. Mantovania,b, V. Mariania,b, M. Menichellia, A. Rossia,b, A. Santocchiaa,b, D. Spigaa INFN Sezione di Pisa a, Universit`a di Pisa b, Scuola Normale Superiore di Pisa c, Pisa, Italy K. Androsova, P. Azzurria, G. Bagliesia, V. Bertacchia,c, L. Bianchinia, T. Boccalia, b K. Androsova, P. Azzurria, G. Bagliesia, V. Bertacchia,c, L. Bianchinia, T. Boccalia, R. Castaldia, M.A. Cioccia,b, R. Dell’Orsoa, G. Fedia, L. Gianninia,c, A. Giassia, b K. Androsova, P. Azzurria, G. Bagliesia, V. Bertacchia,c, L. Bianchinia, T. Boccalia, R. Castaldia, M.A. Cioccia,b, R. Dell’Orsoa, G. Fedia, L. Gianninia,c, A. Giassia, M.T. Grippoa, F. Ligabuea,c, E. Mancaa,c, G. Mandorlia,c, A. Messineoa,b, F. Pallaa, A. Rizzia,b, G. Rolandi31, S. Roy Chowdhury, A. Scribanoa, P. Spagnoloa, R. Tenchinia, G. Tonellia,b, N. Turini, A. Venturia, P.G. Verdinia JHEP11(2019)109 INFN Sezione di Roma a, Sapienza Universit`a di Roma b, Rome, Italy F. Cavallaria, M. Cipriania,b, D. Del Rea,b, E. Di Marcoa,b, M. Diemoza, E. Longoa,b, B. Marzocchia,b, P. Meridiania, G. Organtinia,b, F. Pandolfia, R. Paramattia,b, C. Quarantaa,b, S. Rahatloua,b, C. Rovellia, F. Santanastasioa,b, L. Soffia,b INFN Sezione di Torino a, Universit`a di Torino b, Torino, Italy, Universit`a del Piemonte Orientale c, Novara, Italy N. Amapanea,b, R. Arcidiaconoa,c, S. Argiroa,b, M. Arneodoa,c, N. Bartosika, R. Bellana,b, A B ll C Bii a A C tia b N C ti li a S C ttia M C t a b Bellora, C. Biinoa, A. Cappatia,b, N. Cartigliaa, S. Comettia, M. Costaa,b, R. Covarellia,b, N. Demariaa, B. Kiania,b, C. Mariottia, S. Masellia, E. Migliorea V. Sejong University, Seoul, Korea Seoul National University, Seoul, Korea J. Almond, J.H. Bhyun, J. Choi, S. Jeon, J. Kim, J.S. Kim, H. Lee, K. Lee, S. Lee, K. Nam, M. Oh, S.B. Oh, B.C. Radburn-Smith, U.K. Yang, H.D. Yoo, I. Yoon, G.B. Yu University of Seoul, Seoul, Korea D. Jeon, H. Kim, J.H. Kim, J.S.H. Lee, I.C. Park, I.J Watson University of Seoul, Seoul, Korea D. Jeon, H. Kim, J.H. Kim, J.S.H. Lee, I.C. Park, I.J Watson D. Jeon, H. Kim, J.H. Kim, J.S.H. Lee, I.C. Park, I.J Watson Sungkyunkwan University, Suwon, Korea Y. Choi, C. Hwang, Y. Jeong, J. Lee, Y. Lee, I. Yu Sungkyunkwan University, Suwon, Korea Y. Choi, C. Hwang, Y. Jeong, J. Lee, Y. Lee, I. Yu JHEP11(2019)109 Y. Choi, C. Hwang, Y. Jeong, J. Lee, Y. Lee, I. Yu Riga Technical University, Riga, Latvia V. Veckalns32 Vilnius University, Vilnius, Lithuania V. Dudenas, A. Juodagalvis, G. Tamulaitis, J. Vaitkus National Centre for Particle Physics, Universiti Malaya, Kuala Lumpur, Malaysia Z.A. Ibrahim, F. Mohamad Idris33, W.A.T. Wan Abdullah, M.N. Yusli, Z. Zolkapli Universidad de Sonora (UNISON), Hermosillo, Mexico J.F. Benitez, A. Castaneda Hernandez, J.A. Murillo Quijada, L. Valencia Palomo Centro de Investigacion y de Estudios Avanzados del IPN, Mexico City, Mexico H. Castilla-Valdez, E. De La Cruz-Burelo, I. Heredia-De La Cruz34, R. Lopez-Fernandez, A. Sanchez-Hernandez Universidad Iberoamericana, Mexico City, Mexico S. Carrillo Moreno, C. Oropeza Barrera, M. Ramirez-Garcia, F. Vazquez Valencia Benemerita Universidad Autonoma de Puebla, Puebla, Mexico J. Eysermans, I. Pedraza, H.A. Salazar Ibarguen, C. Uribe Estrada Universidad Aut´onoma de San Luis Potos´ı, San Luis Potos´ı, Mexico A. Morelos Pineda University of Montenegro, Podgorica, Montenegro J. Mijuskovic, N. Raicevic University of Auckland, Auckland, New Zealand D. Krofcheck University of Canterbury, Christchurch, New Zealand S. Bheesette, P.H. Butler National Centre for Physics, Quaid-I-Azam University, Islamabad, Pakistan A. Ahmad, M. Ahmad, Q. Hassan, H.R. Hoorani, W.A. Khan, M.A. Shah, M. Shoaib, M. Waqas Riga Technical University, Riga, Latvia V. Veckalns32 Riga Technical University, Riga, Latvia V. Veckalns32 Vilnius University, Vilnius, Lithuania V. Dudenas, A. Juodagalvis, G. Tamulaitis, J. Vaitkus Vilnius University, Vilnius, Lithuania V. Dudenas, A. Juodagalvis, G. Tamulaitis, J. Vaitkus National Centre for Particle Physics, Universiti Malaya, Kuala Lumpur, Malaysia Z.A. Ibrahim, F. Mohamad Idris33, W.A.T. Wan Abdullah, M.N. Yusli, Z. Zolkapli Universidad de Sonora (UNISON), Hermosillo, Mexico J.F. Benitez, A. Castaneda Hernandez, J.A. Murillo Quijada, L. ata Institute of Fundamental Research-B, Mumbai, India Monacoa,b, E. Monteila,b, M. Montenoa, M.M. Obertinoa,b, G. Ortonaa,b, L. Pachera N. Pastronea, M. Pelliccionia, G.L. Pinna Angionia,b, A. Romeroa,b, M. Ruspaa,c, R. Salvaticoa,b, V. Solaa, A. Solanoa,b, D. Soldia,b, A. Staianoa N. Pastronea, M. Pelliccionia, G.L. Pinna Angionia,b, A. Romeroa,b, M. Ruspaa N. Pastrone , M. Pelliccioni , G.L. Pinna Angioni , A. Romero , M. Ruspa , R. Salvaticoa,b, V. Solaa, A. Solanoa,b, D. Soldia,b, A. Staianoa INFN Sezione di Trieste a, Universit`a di Trieste b, Trieste, Italy S. Belfortea, V. Candelisea,b, M. Casarsaa, F. Cossuttia, A. Da Rolda,b, G. Della Riccaa,b, F. Vazzolera,b, A. Zanettia Kyungpook National University, Daegu, Korea B. Kim, D.H. Kim, G.N. Kim, J. Lee, S.W. Lee, C.S. Moon, Y.D. Oh, S.I. Pak, S. Sekmen, D.C. Son, Y.C. Yang Chonnam National University, Institute for Universe and Elementary Particles, Kwangju, Korea H. Kim, D.H. Moon, G. Oh H. Kim, D.H. Moon, G. Oh Hanyang University, Seoul, Korea B. Francois, T.J. Kim, J. Park Hanyang University, Seoul, Korea B. Francois, T.J. Kim, J. Park Hanyang University, Seoul, Korea B. Francois, T.J. Kim, J. Park Korea University, Seoul, Korea S. Cho, S. Choi, Y. Go, D. Gyun, S. Ha, B. Hong, K. Lee, K.S. Lee, J. Lim, J. Park, S.K. Park, Y. Roh, J. Yoo Kyung Hee University, Department of Physics J. Goh Kyung Hee University, Department of Physics J. Goh – 37 – Sejong University, Seoul, Korea Valencia Palomo Centro de Investigacion y de Estudios Avanzados del IPN, Mexico City, Mexico H. Castilla-Valdez, E. De La Cruz-Burelo, I. Heredia-De La Cruz34, R. Lopez-Fernandez, A. Sanchez-Hernandez Universidad Iberoamericana, Mexico City, Mexico S. Carrillo Moreno, C. Oropeza Barrera, M. Ramirez-Garcia, F. Vazquez Valen Benemerita Universidad Autonoma de Puebla, Puebla, Mexico J. Eysermans, I. Pedraza, H.A. Salazar Ibarguen, C. Uribe Estrada Universidad Aut´onoma de San Luis Potos´ı, San Luis Potos´ı, Mexico A. Morelos Pineda University of Montenegro, Podgorica, Montenegro J. Mijuskovic, N. Raicevic University of Auckland, Auckland, New Zealand D. Krofcheck University of Canterbury, Christchurch, New Zealand S. Bheesette, P.H. Butler National Centre for Physics, Quaid-I-Azam University, Islamabad, Pakistan A. Ahmad, M. Ahmad, Q. Hassan, H.R. Hoorani, W.A. Khan, M.A. Shah, M. Shoaib, M. Waqas National Centre for Physics, Quaid-I-Azam University, Islamabad, Pakistan A. Ahmad, M. Ahmad, Q. Hassan, H.R. Hoorani, W.A. Khan, M.A. Shah, M. Shoaib, M. Waqas – 38 – AGH University of Science and Technology Faculty of Computer Science, Electronics and Telecommunications, Krakow, Poland V. Avati, L. Grzanka, M. Malawski National Centre for Nuclear Research, Swierk, Poland H. Bialkowska, M. Bluj, B. Boimska, M. G´orski, M. Kazana, M. Szleper, P. Zalewski Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw, Poland K. Bunkowski, A. Byszuk35, K. Doroba, A. Kalinowski, M. Konecki, J. Krolikowski, M. Misiura, M. Olszewski, M. Walczak JHEP11(2019)109 Laborat´orio de Instrumenta¸c˜ao e F´ısica Experimental de Part´ıculas, Lisboa, Portugal Portugal M. Araujo, P. Bargassa, D. Bastos, A. Di Francesco, P. Faccioli, B. Galinhas, M. Gallinaro, J. Hollar, N. Leonardo, J. Seixas, K. Shchelina, G. Strong, O. Toldaiev, J. Varela Joint Institute for Nuclear Research, Dubna, Russia Joint Institute for Nuclear Research, Dubna, Russia V. Alexakhin, P. Bunin, I. Golutvin, I. Gorbunov, A. Kamenev, V. Karjavine, V. Korenkov, A. Lanev, A. Malakhov, V. Matveev36,37, P. Moisenz, V. Palichik, V. Perelygin, M. Savina, S. Shmatov, S. Shulha, V. Trofimov, N. Voytishin, A. Zarubin, V. Zhiltsov Petersburg Nuclear Physics Institute, Gatchina (St. Petersburg), Russia L. Chtchipounov, V. Golovtcov, Y. Ivanov, V. Kim38, E. Kuznetsova39, P. Levchenko, V. Murzin, V. Oreshkin, I. Smirnov, D. Sosnov, V. Sulimov, L. Uvarov, A. Vorobyev Institute for Nuclear Research, Moscow, Russia Institute for Nuclear Research, Moscow, Russia Yu. Andreev, A. Dermenev, S. Gninenko, N. Golubev, A. Karneyeu, M. Kirsanov, N. Krasnikov, A. Pashenkov, D. Tlisov, A. Toropin Institute for Theoretical and Experimental Physics named by A.I. Alikhanov of NRC ‘Kurchatov Institute’, Moscow, Russia V. Epshteyn, V. Gavrilov, N. Lychkovskaya, A. Nikitenko40, V. Popov, I. Pozdnyakov, G. Safronov, A. Spiridonov, A. Stepennov, M. Toms, E. Vlasov, A. Zhokin Epshteyn, V. Gavrilov, N. Lychkovskaya, A. Nikitenko40, V. Popov, I. Pozdnyakov, Safronov, A. Spiridonov, A. Stepennov, M. Toms, E. Vlasov, A. Zhokin Moscow Institute of Physics and Technology, Moscow, Russia T. Aushev National Research Nuclear University ’Moscow Engineering Physics Institute’ (MEPhI), Moscow, Russia M. Chadeeva41, P. Parygin, D. Philippov, E. Popova, V. Rusinov P.N. Lebedev Physical Institute, Moscow, Russia P.N. Lebedev Physical Institute, Moscow, Russia V. Andreev, M. Azarkin, I. Dremin, M. Kirakosyan, A. Terkulov y , , V. Andreev, M. Azarkin, I. Dremin, M. Kirakosyan, A. Terkulov V. Andreev, M. Azarkin, I. Dremin, M. Kirakosyan, A. Terkulov Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, Russia A. Belyaev, E. Boos, V. Bunichev, M. Dubinin42, L. Dudko, A. Ershov, A. Gribushin, V. Klyukhin, O. Kodolova, I. Lokhtin, S. Obraztsov, V. Savrin, A. Snigirev V. Klyukhin, O. Kodolova, I. Lokhtin, S. Obraztsov, V. Savrin, A. Snigirev – 39 – Novosibirsk State University (NSU), Novosibirsk, Russia A. Barnyakov43, V. Blinov43, T. Dimova43, L. Kardapoltsev43, Y. Skovpen43 Novosibirsk State University (NSU), Novosibirsk, Russia A. Barnyakov43, V. Blinov43, T. Dimova43, L. Kardapoltsev43, Y. Skovpen43 Institute for High Energy Physics of National Research Centre ‘Kurchatov Institute’, Protvino, Russia I. Azhgirey, I. Bayshev, S. Bitioukov, V. Kachanov, D. Konstantinov, P. Mandrik, V. Petrov, R. Portugal Ryutin, S. Slabospitskii, A. Sobol, S. Troshin, N. Tyurin, A. Uzunian, A. Volkov Centro de Investigaciones Energ´eticas Medioambientales y Tecnol´ogica (CIEMAT), Madrid, Spain M. Aguilar-Benitez, J. Alcaraz Maestre, A. ´Alvarez Fern´andez, I. Bachiller, M. Barrio Lun M. Aguilar-Benitez, J. Alcaraz Maestre, A. Alvarez Fernandez, I. Bachiller, M. Barrio Luna, J.A. Brochero Cifuentes, C.A. Carrillo Montoya, M. Cepeda, M. Cerrada, N. Colino, B. De La Cruz, A. Delgado Peris, C. Fernandez Bedoya, J.P. Fern´andez Ramos, J. Flix, M.C. Fouz, O. Gonzalez Lopez, S. Goy Lopez, J.M. Hernandez, M.I. Josa, D. Moran, ´A. Navarro Tobar, A. P´erez-Calero Yzquierdo, J. Puerta Pelayo, I. Redondo, L. Romero, S. S´anchez Navas, M.S. Soares, A. Triossi, C. Willmott Universidad Aut´onoma de Madrid, Madrid, Spain C. Albajar, J.F. de Troc´oniz, R. Reyes-Almanza Universidad de Oviedo, Instituto Universitario de Ciencias y Tecnolog´ıas Espaciales de Asturias (ICTEA), Oviedo, Spain B. Alvarez Gonzalez, J. Cuevas, C. Erice, J. Fernandez Menendez, S. Folgueras, I. Gon- zalez Caballero, J.R. Gonz´alez Fern´andez, E. Palencia Cortezon, V. Rodr´ıguez Bouza, S. Sanchez Cruz National Research Tomsk Polytechnic University, Tomsk, Russia A. Babaev, A. Iuzhakov, V. Okhotnikov National Research Tomsk Polytechnic University, Tomsk, Russia A. Babaev, A. Iuzhakov, V. Okhotnikov JHEP11(2019)109 Tomsk State University, Tomsk, Russia V. Borchsh, V. Ivanchenko, E. Tcherniaev University of Belgrade: Faculty of Physics and VINCA Institute of Nuclear Sciences P. Adzic44, P. Cirkovic, D. Devetak, M. Dordevic, P. Milenovic, J. Milosevic, M. Stojanov Centro de Investigaciones Energ´eticas Medioambientales y Tecnol´ogicas (CIEMAT), Madrid, Spain Instituto de F´ısica de Cantabria (IFCA), CSIC-Universidad de Cantabria, Santander, Spain Instituto de F´ısica de Cantabria (IFCA), CSIC-Universidad de Cantabria, Santander, Spain I.J. Cabrillo, A. Calderon, B. Chazin Quero, J. Duarte Campderros, M. Fernandez, P.J. Fern´andez Manteca, A. Garc´ıa Alonso, G. Gomez, C. Martinez Rivero, P. Mar- tinez Ruiz del Arbol, F. Matorras, J. Piedra Gomez, C. Prieels, T. Rodrigo, A. Ruiz-Jimeno, L. Russo45, L. Scodellaro, N. Trevisani, I. Vila, J.M. Vizan Garcia University of Colombo, Colombo, Sri Lanka K. Malagalage University of Colombo, Colombo, Sri Lanka K. Malagalage University of Ruhuna, Department of Physics, Matara, Sri Lanka W.G.D. Dharmaratna, N. Wickramage – 40 – CERN, European Organization for Nuclear Research, Geneva, Switzerland D. Abbaneo, B. Akgun, E. Auffray, G. Auzinger, J. Baechler, P. Baillon, A.H. Ball, D. Barney, J. Bendavid, M. Bianco, A. Bocci, P. Bortignon, E. Bossini, C. Botta, E. Brondolin, T. Camporesi, A. Caratelli, G. Cerminara, E. Chapon, G. Cucciati, D. d’Enterria, A. Dabrowski, N. Daci, V. Daponte, A. David, O. Davignon, A. De Roeck, N. Deelen, M. Deile, M. Dobson, M. D¨unser, N. Dupont, A. Elliott-Peisert, N. Emriskova, F. Fallavollita46, D. Fasanella, S. Fiorendi, G. Franzoni, J. Fulcher, W. Funk, S. Giani, D. Gigi, A. Gilbert, K. Gill, F. Glege, M. Gruchala, M. Guilbaud, D. Gulhan, J. Hegeman, C. Heidegger, Y. Iiyama, V. Innocente, P. Janot, O. Karacheban19, J. Kaspar, J. Kieseler, M. Krammer1, N. Kratochwil, C. Lange, P. Lecoq, C. Louren¸co, L. Malgeri, M. Mannelli, A. Massironi, F. Meijers, J.A. Merlin, S. Mersi, E. Meschi, F. Moortgat, M. Mulders, J. Ngadiuba, J. Niedziela, S. Nourbakhsh, S. Orfanelli, L. Orsini, F. Pantaleo16, L. Pape, E. Perez, M. Peruzzi, A. Petrilli, G. Petrucciani, A. Pfeiffer, M. Pierini, F.M. Pitters, D. Rabady, A. Racz, M. Rieger, M. Rovere, H. Sakulin, C. Sch¨afer, C. Schwick, M. Selvaggi, A. Sharma, P. Silva, W. Snoeys, P. Sphicas47, J. Steggemann, S. Summers, V.R. Tavolaro, D. Treille, A. Tsirou, G.P. Van Onsem, A. Vartak, M. Verzetti, W.D. Zeuner CERN, European Organization for Nuclear Research, Geneva, Switzerland D. Abbaneo, B. Akgun, E. Auffray, G. Auzinger, J. Baechler, P. Baillon, A.H. Ball, D. Barney, J. Bendavid, M. Bianco, A. Bocci, P. Bortignon, E. Bossini, C. Botta, E. Brondolin, T. Camporesi, A. Caratelli, G. Cerminara, E. Chapon, G. Cucciati, D. d’Enterria, A. Dabrowski, N. Daci, V. Daponte, A. David, O. Davignon, A. De Roeck, N. Deelen, M. Deile, M. Dobson, M. D¨unser, N. Dupont, A. Elliott-Peisert, N. Emriskova, F. Fallavollita46, D. Fasanella, S. Fiorendi, G. Franzoni, J. Instituto de F´ısica de Cantabria (IFCA), CSIC-Universidad de Cantabria, Santander, Spain Fulcher, W. Funk, S. Giani, D. Gigi, A. Gilbert, K. Gill, F. Glege, M. Gruchala, M. Guilbaud, D. Gulhan, J. Hegeman, C. Heidegger, Y. Iiyama, V. Innocente, P. Janot, O. Karacheban19, J. Kaspar, J. Kieseler, M. Krammer1, N. Kratochwil, C. Lange, P. Lecoq, C. Louren¸co, L. Malgeri, M. Mannelli, A. Massironi, F. Meijers, J.A. Merlin, S. Mersi, E. Meschi, F. Moortgat, M. Mulders, J. Ngadiuba, J. Niedziela, S. Nourbakhsh, S. Orfanelli, L. Orsini, F. Pantaleo16, L. Pape, E. Perez, M. Peruzzi, A. Petrilli, G. Petrucciani, A. Pfeiffer, M. Pierini, F.M. Pitters, D. Rabady, A. Racz, M. Rieger, M. Rovere, H. Sakulin, C. Sch¨afer, C. Schwick, M. Selvaggi, A. Sharma, P. Silva, W. Snoeys, P. Sphicas47, J. Steggemann, S. Summers, V.R. Tavolaro, D. Treille, A. Tsirou, G.P. Van Onsem, A. Vartak, M. Verzetti, W.D. Zeuner JHEP11(2019)109 Universit¨at Z¨urich, Zurich, Switzerland , , T.K. Aarrestad, C. Amsler49, D. Brzhechko, M.F. Canelli, A. De Cosa, R. Del Burgo, S. Do- nato, B. Kilminster, S. Leontsinis, V.M. Mikuni, I. Neutelings, G. Rauco, P. Robmann, D. Salerno, K. Schweiger, C. Seitz, Y. Takahashi, S. Wertz, A. Zucchetta National Central University, Chung-Li, Taiwan National Central University, Chung-Li, Taiwan T.H. Doan, C.M. Kuo, W. Lin, A. Roy, S.S. Yu T.H. Doan, C.M. Kuo, W. Lin, A. Roy, S.S. Yu National Taiwan University (NTU), Taipei, Taiwan P. Chang, Y. Chao, K.F. Chen, P.H. Chen, W.-S. Hou, Y.y. Li, R.-S. Lu, E. Paganis, National Taiwan University (NTU), Taipei, Taiwan National Taiwan University (NTU), Taipei, Taiwan P. Chang, Y. Chao, K.F. Chen, P.H. Chen, W.-S. Hou, Y.y. Li, R.-S. Lu, E. Paganis, A. Psallidas, A. Steen Paul Scherrer Institut, Villigen, Switzerland Paul Scherrer Institut, Villigen, Switzerland Paul Scherrer Institut, Villigen, Switzerland L. Caminada48, K. Deiters, W. Erdmann, R. Horisberger, Q. Ingram, H.C. Kaestli, D. Kotlinski, U. Langenegger, T. Rohe, S.A. Wiederkehr ETH Zurich - Institute for Particle Physics and Astrophysics (IPA), Zurich, Switzerland M. Backhaus, P. Berger, N. Chernyavskaya, G. Dissertori, M. Dittmar, M. Doneg`a, C. Dor- fer, T.A. G´omez Espinosa, C. Grab, D. Hits, T. Klijnsma, W. Lustermann, R.A. Manzoni, M. Marionneau, M.T. Meinhard, F. Micheli, P. Musella, F. Nessi-Tedaldi, F. Pauss, G. Perrin, L. Perrozzi, S. Pigazzini, M.G. Ratti, M. Reichmann, C. Reissel, T. Reitenspiess, D R i i D A S B M S h¨ b L Sh h t k M L V t b k Ol D. Ruini, D.A. Sanz Becerra, M. Sch¨onenberger, L. Shchutska, M.L. Vesterbacka Olsson, R. Wallny, D.H. Zhu R. Wallny, D.H. Zhu University of Bristol, Bristol, U.K. University of Bristol, Bristol, U.K. F. Ball, E. Bhal, S. Bologna, J.J. Brooke, D. Burns64, E. Clement, D. Cussans, H. Flacher, J. Goldstein, G.P. Heath, H.F. Heath, L. Kreczko, S. Paramesvaran, B. Penning, T. Sakuma, S. Seif El Nasr-Storey, V.J. Smith, J. Taylor, A. Titterton Rutherford Appleton Laboratory, Didcot, U.K. K.W. Bell, A. Belyaev65, C. Brew, R.M. Brown, D. Cieri, D.J.A. Cockerill, J.A. Coughlan, K. Harder, S. Harper, J. Linacre, K. Manolopoulos, D.M. Newbold, E. Olaiya, D. Petyt, T. Reis, T. Schuh, C.H. Shepherd-Themistocleous, A. Thea, I.R. Tomalin, T. Williams, W.J. Womersley Chulalongkorn University, Faculty of Science, Department of Physics, Bangkok, Thailand Chulalongkorn University, Faculty of Science, Department of Physics, Bangkok, Thailand Chulalongkorn University, Faculty of Science, Department of Physics, Bangkok, Thailand B. Asavapibhop, C. Asawatangtrakuldee, N. Srimanobhas, N. Suwonjandee B. Asavapibhop, C. Asawatangtrakuldee, N. Srimanobhas, N. Suwonjandee B. Asavapibhop, C. Asawatangtrakuldee, N. Srimanobhas, N. Suwonjandee – 41 – C¸ ukurova University, Physics Department, Science and Art Faculty, Adana, Turkey A. Bat, F. Boran, A. Celik50, S. Cerci51, S. Damarseckin52, Z.S. Demiroglu, F. Dole A. Bat, F. Boran, A. Celik , S. Cerci , S. Damarseckin , Z.S. Demiroglu, F. Dolek, C. Dozen, I. Dumanoglu, G. Gokbulut, EmineGurpinar Guler53, Y. Guler, I. Hos54, C. Isik, E.E. Kangal55, O. Kara, A. Kayis Topaksu, U. Kiminsu, M. Oglakci, G. Onengut, K. Ozdemir56, S. Ozturk57, A.E. Simsek, D. Sunar Cerci51, U.G. Tok, S. Turkcapar, I.S. Zorbakir, C. Zorbilmez Middle East Technical University, Physics Department, Ankara, Turkey B. Isildak58, G. Karapinar59, M. Yalvac JHEP11(2019)109 Bogazici University, Istanbul, Turkey I.O. Atakisi, E. G¨ulmez, M. Kaya60, O. Kaya61, ¨O. ¨Oz¸celik, S. Tekten, E.A. Yetkin62 Istanbul Technical University, Istanbul, Turkey A. Cakir, K. Cankocak, Y. Komurcu, S. Sen63 Istanbul Technical University, Istanbul, Turkey A. Cakir, K. Cankocak, Y. Komurcu, S. Sen63 Istanbul University, Istanbul, Turkey B. Kaynak, S. Ozkorucuklu Istanbul University, Istanbul, Turkey B. Kaynak, S. Ozkorucuklu Institute for Scintillation Materials of National Academy of Science of Ukraine, Kharkov, Ukraine B. Grynyov National Scientific Center, Kharkov Institute of Physics and Technology, Kharkov, Ukraine L. Levchuk L. Levchuk L. Levchuk University of Bristol, Bristol, U.K. Baylor University, Waco, U.S.A. Baylor University, Waco, U.S.A. K. Call, B. Caraway, J. Dittmann, K. Hatakeyama, C. Madrid, B. McMaster, N. Pastika, C. Smith Catholic University of America, Washington, DC, U.S.A. Catholic University of America, Washington, DC, U.S.A. R. Bartek, A. Dominguez, R. Uniyal, A.M. Vargas Hernandez JHEP11(2019)109 The University of Alabama, Tuscaloosa, U.S.A. A B illi S I C C H d P R i C W t The University of Alabama, Tuscaloosa, U.S.A. A. Buccilli, S.I. Cooper, C. Henderson, P. Rumerio, C. West Boston University, Boston, U.S.A. D. Arcaro, Z. Demiragli, D. Gastler, D. Pinna, C. Richardson, J. Rohlf, D. Sperka, I. Suarez, L. Sulak, D. Zou Brown University, Providence, U.S.A. G. Benelli, B. Burkle, X. Coubez17, D. Cutts, Y.t. Duh, M. Hadley, J. Hakala, U. Heint J.M. Hogan68, K.H.M. Kwok, E. Laird, G. Landsberg, J. Lee, Z. Mao, M. Narain, S. Sagir69, R. Syarif, E. Usai, D. Yu, W. Zhang University of California, Davis, Davis, U.S.A. R. Band, C. Brainerd, R. Breedon, M. Calderon De La Barca Sanchez, M. Chertok, R. Band, C. Brainerd, R. Breedon, M. Calderon De La Barca Sanchez, M. Chertok, J. Conway, R. Conway, P.T. Cox, R. Erbacher, C. Flores, G. Funk, F. Jensen, W. Ko, J. Conway, R. Conway, P.T. Cox, R. Erbacher, C. Flores, G. Funk, F. Jensen, W. Ko, O. Kukral, R. Lander, M. Mulhearn, D. Pellett, J. Pilot, M. Shi, D. Taylor, K. Tos, M. Tripathi, Z. Wang, F. Zhang O. Kukral, R. Lander, M. Mulhearn, D. Pellett, J. Pilot, M. Shi, D. Taylor, K. Tos, O. Kukral, R. Lander, M. Mulhearn, D. Pellett, J. Pilot, M. Shi, D. Taylor, K. Tos, M Tripathi Z Wang F Zhang M. Tripathi, Z. Wang, F. Zhang Imperial College, London, U.K. Imperial College, London, U.K. R. Bainbridge, P. Bloch, J. Borg, S. Breeze, O. Buchmuller, A. Bundock, GurpreetS- ingh CHAHAL66, D. Colling, P. Dauncey, G. Davies, M. Della Negra, R. Di Maria, P. Everaerts, G. Hall, G. Iles, T. James, M. Komm, C. Laner, L. Lyons, A.-M. Magnan, S. Malik, A. Martelli, V. Milosevic, J. Nash67, V. Palladino, M. Pesaresi, D.M. Raymond, A. Richards, A. Rose, E. Scott, C. Seez, A. Shtipliyski, M. Stoye, T. Strebler, A. Tapper, K. Uchida, T. Virdee16, N. Wardle, D. Winterbottom, J. Wright, A.G. Zecchinelli, S.C. Zenz K. Uchida, T. Virdee16, N. Wardle, D. Winterbottom, J. Wright, A.G. Zecchinelli, S.C. Zenz – 42 – Brunel University, Uxbridge, U.K. Brunel University, Uxbridge, U.K. J.E. Cole, P.R. Hobson, A. Khan, P. Kyberd, C.K. Mackay, A. Morton, I.D. Reid, L. Teodorescu, S. Zahid University of Colorado Boulder, Boulder, U.S.A. J.P. Cumalat, W.T. Ford, A. Johnson, E. MacDonald, T. Mulholland, R. Patel, A. Perloff, K. Stenson, K.A. Ulmer, S.R. Wagner JHEP11(2019)109 Fermi National Accelerator Laboratory, Batavia, U.S.A. S. Abdullin, M. Albrow, M. Alyari, G. Apollinari, A. Apresyan, A. Apyan, S. Banerjee, L.A.T. Bauerdick, A. Beretvas, J. Berryhill, P.C. Bhat, K. Burkett, J.N. Butler, A. Canepa, G.B. Cerati, H.W.K. Cheung, F. Chlebana, M. Cremonesi, J. Duarte, V.D. Elvira, J. Freeman, Z. Gecse, E. Gottschalk, L. Gray, D. Green, S. Gr¨unendahl, O. Gutsche, AllisonReinsvold Hall, J. Hanlon, R.M. Harris, S. Hasegawa, R. Heller, J. Hirschauer, B. Jayatilaka, S. Jindariani, M. Johnson, U. Joshi, B. Klima, M.J. Kortelainen, B. Kreis, S. Lammel, J. Lewis, D. Lincoln, R. Lipton, M. Liu, T. Liu, J. Lykken, K. Maeshima, J.M. Marraffino, D. Mason, P. McBride, P. Merkel, S. Mrenna, S. Nahn, V. O’Dell, V. Papadimitriou, K. Pedro, C. Pena, G. Rakness, F. Ravera, L. Ristori, B. Schneider, E. Sexton-Kennedy, N. Smith, A. Soha, W.J. Spalding, L. Spiegel, S. Stoynev, J. Strait, N. Strobbe, L. Taylor, S. Tkaczyk, N.V. Tran, L. Uplegger, E.W. Vaandering, C. Vernieri, R. Vidal, M. Wang, H.A. Weber J.M. Marraffino, D. Mason, P. McBride, P. Merkel, S. Mrenna, S. Nahn, V. O’Dell, E. Sexton-Kennedy, N. Smith, A. Soha, W.J. Spalding, L. Spiegel, S. Stoynev, J. Strait, N. Strobbe, L. Taylor, S. Tkaczyk, N.V. Tran, L. Uplegger, E.W. Vaandering, C. Vernieri, R Vidal M Wang H A Weber E. Sexton-Kennedy, N. Smith, A. Soha, W.J. Spalding, L. Spiegel, S. Stoynev, J. Strait, N St bb L T l S Tk k N V T L U l gg E W V d i g C V i i N. Strobbe, L. Taylor, S. Tkaczyk, N.V. Tran, L. Uplegger, E.W. Vaandering, C. Vernie R. Vidal, M. Wang, H.A. Weber University of California, Los Angeles, U.S.A. University of California, Los Angeles, U.S.A. . Bachtis, C. Bravo, R. Cousins, A. Dasgupta, A. Florent, J. Hauser, M. Ignatenko, M. Bachtis, C. Bravo, R. Cousins, A. Dasgupta, A. Florent, J. Hauser, M. Ignatenko, N. Mccoll, W.A. Nash, S. Regnard, D. Saltzberg, C. Schnaible, B. Stone, V. Valuev N. Mccoll, W.A. Nash, S. Regnard, D. Saltzberg, C. Schnaible, B. Stone, V. Valuev University of California, Riverside, Riverside, U.S.A. K. Burt, Y. Chen, R. Clare, J.W. Gary, S.M.A. Ghiasi Shirazi, G. Hanson, G. Karapostoli, E. Kennedy, O.R. Long, M. Olmedo Negrete, M.I. Paneva, W. Si, L. Wang, S. Wimpenny, B.R. Yates, Y. Zhang B.R. Yates, Y. Zhang University of California, San Diego, La Jolla, U.S.A. J.G. Branson, P. Chang, S. Cittolin, M. Derdzinski, R. Gerosa, D. Gilbert, B. Hashemi, D. Klein, V. Krutelyov, J. Letts, M. Masciovecchio, S. May, S. Padhi, M. Pieri, V. Sharma, M. Tadel, F. W¨urthwein, A. Yagil, G. Zevi Della Porta University of California, Santa Barbara - Department of Physics, Santa Bar- bara, U.S.A. N. Amin, R. Bhandari, C. Campagnari, M. Citron, V. Dutta, M. Franco Sevilla, L. Gouskos, N. Amin, R. Bhandari, C. Campagnari, M. Citron, V. Dutta, M. Franco Sevilla, L. Gouskos, J Incandela B Marsh H Mei A Ovcharova H Qu J Richman U Sarica D Stuart J. Incandela, B. Marsh, H. Mei, A. Ovcharova, H. Qu, J. Richman, U. Sarica, D. Stuart, S. Wang – 43 – University of Florida, Gainesville, U.S.A. D. Acosta, P. Avery, D. Bourilkov, A. Brinkerhoff, L. Cadamuro, A. Carnes, V. Cherepanov, D. Curry, F. Errico, R.D. Field, S.V. Gleyzer, B.M. Joshi, M. Kim, J. Konigsberg, A. Korytov, K.H. Lo, P. Ma, K. Matchev, N. Menendez, G. Mitselmakher, D. Rosenzweig, K. Shi, J. Wang, S. Wang, X. Zuo Florida International University, Miami, U.S.A. Florida International University, Miami, U.S.A. Y.R. Joshi Y.R. Joshi Florida State University, Tallahassee, U.S.A. T. Adams, A. Askew, S. Hagopian, V. Hagopian, K.F. Johnson, R. Khurana, T. Kolber T. Adams, A. Askew, S. Hagopian, V. Hagopian, K.F. Johnson, R. Khurana, T. Kolberg, G. Martinez, T. Perry, H. Prosper, C. Schiber, R. Yohay, J. Zhang Martinez, T. Perry, H. Prosper, C. Schiber, R. Yohay, J. Zhang G. Martinez, T. Perry, H. Prosper, C. Schiber, R. Yohay, J. Zhan Florida Institute of Technology, Melbourne, U.S.A. Cornell University, Ithaca, U.S.A. J. Alexander, J. Chaves, Y. Cheng, J. Chu, A. Datta, A. Frankenthal, K. Mcdermott, J.R. Patterson, D. Quach, A. Rinkevicius70, A. Ryd, S.M. Tan, Z. Tao, J. Thom, P. Wittich, M. Zientek Fermi National Accelerator Laboratory, Batavia, U.S.A. California Institute of Technology, Pasadena, U.S.A. California Institute of Technology, Pasadena, U.S.A. D. Anderson, A. Bornheim, O. Cerri, I. Dutta, J.M. Lawhorn, N. Lu, J. Mao, H.B. Newman, T.Q. Nguyen, J. Pata, M. Spiropulu, J.R. Vlimant, S. Xie, Z. Zhang, R.Y. Zhu Carnegie Mellon University, Pittsburgh, U.S.A. M.B. Andrews, T. Ferguson, T. Mudholkar, M. Paulini, M. Sun, I. Vorobiev, M. Weinberg M.B. Andrews, T. Ferguson, T. Mudholkar, M. Paulini, M. Sun, I. Vorobiev, M. Weinbe University of Colorado Boulder, Boulder, U.S.A. Florida Institute of Technology, Melbourne, U.S.A. Acosta, S. Oliveros Florida Institute of Technology, Melbourne, U.S.A. M.M. Baarmand, M. Hohlmann, D. Noonan, M. Rahmani, M. Saunders, F. Yumiceva – 44 – University of Illinois at Chicago (UIC), Chicago, U.S.A. M.R. Adams, L. Apanasevich, D. Berry, R.R. Betts, R. Cavanaugh, X. Chen, S. Dittmer, O. Evdokimov, C.E. Gerber, D.A. Hangal, D.J. Hofman, K. Jung, C. Mills, T. Roy, M.B. Tonjes, N. Varelas, J. Viinikainen, H. Wang, X. Wang, Z. Wu The University of Iowa, Iowa City, U.S.A. M. Alhusseini, B. Bilki53, W. Clarida, K. Dilsiz71, S. Durgut, R.P. Gandrajula, M. Hayt- myradov, V. Khristenko, O.K. K¨oseyan, J.-P. Merlo, A. Mestvirishvili72, A. Moeller, J. Nachtman, H. Ogul73, Y. Onel, F. Ozok74, A. Penzo, C. Snyder, E. Tiras, J. Wetzel Johns Hopkins University, Baltimore, U.S.A. JHEP11(2019)109 B. Blumenfeld, A. Cocoros, N. Eminizer, D. Fehling, L. Feng, A.V. Gritsan, W.T. Hung, P. Maksimovic, J. Roskes, M. Swartz P. Maksimovic, J. Roskes, M. Swartz The University of Kansas, Lawrence, U.S.A. The University of Kansas, Lawrence, U.S.A. C. Baldenegro Barrera, P. Baringer, A. Bean, S. Boren, J. Bowen, A. Bylinkin, T. Isidori, S. Khalil, J. King, G. Krintiras, A. Kropivnitskaya, C. Lindsey, D. Majumder, W. Mcbrayer, N. Minafra, M. Murray, C. Rogan, C. Royon, S. Sanders, E. Schmitz, J.D. Tapia Takaki, Q. Wang, J. Williams, G. Wilson Kansas State University, Manhattan, U.S.A. S. Duric, A. Ivanov, K. Kaadze, D. Kim, Y. Maravin, D.R. Mendis, T. Mitchell, A. Modak, A. Mohammadi Lawrence Livermore National Laboratory, Livermore, U.S.A. F. Rebassoo, D. Wright University of Maryland, College Park, U.S.A. A. Baden, O. Baron, A. Belloni, S.C. Eno, Y. Feng, N.J. Hadley, S. Jabeen, G.Y. Jeng, R.G. Kellogg, J. Kunkle, A.C. Mignerey, S. Nabili, F. Ricci-Tam, M. Seidel, Y.H. Shin, A. Skuja, S.C. Tonwar, K. Wong Massachusetts Institute of Technology, Cambridge, U.S.A. D. Abercrombie, B. Allen, A. Baty, R. Bi, S. Brandt, W. Busza, I.A. Cali, M. D Alfonso, G. Gomez Ceballos, M. Goncharov, P. Harris, D. Hsu, M. Hu, M. Klute, D. Kovalskyi, Y.-J. Lee, P.D. Luckey, B. Maier, A.C. Marini, C. Mcginn, C. Mironov, S. Narayanan, X. Niu, C. Paus, D. Rankin, C. Roland, G. Roland, Z. Shi, G.S.F. Stephans, K. Sumorok, K. Tatar, D. Velicanu, J. Wang, T.W. Wang, B. Wyslouch University of Minnesota, Minneapolis, U.S.A. A.C. Benvenuti†, R.M. Chatterjee, A. Evans, S. Guts, P. Hansen, J. Hiltbrand, Y. Kubota, Z. Lesko, J. Mans, R. Rusack, M.A. Wadud University of Mississippi, Oxford, U.S.A. J.G. Acosta, S. Oliveros University of Mississippi, Oxford, U.S.A. J.G. University of Nebraska-Lincoln, Lincoln, U.S.A. K. Bloom, D.R. Claes, C. Fangmeier, L. Finco, F. Golf, R. Gonzalez Suarez, R. Kamalied- din, I. Kravchenko, J.E. Siado, G.R. Snow†, B. Stieger, W. Tabb Northeastern University, Boston, U.S.A. Northeastern University, Boston, U.S.A. G. Alverson, E. Barberis, C. Freer, Y. Haddad, A. Hortiangtham, G. Madigan, D.M. Mors G. Alverson, E. Barberis, C. Freer, Y. Haddad, A. Hortiangtham, G. Madigan, D.M. Morse, T. Orimoto, L. Skinnari, A. Tishelman-Charny, T. Wamorkar, B. Wang, A. Wisecarver, D. Wood State University of New York at Buffalo, Buffalo, U.S.A. State University of New York at Buffalo, Buffalo, U.S.A. G. Agarwal, C. Harrington, I. Iashvili, A. Kharchilava, C. McLean, D. Nguyen, A. Parke G. Agarwal, C. Harrington, I. Iashvili, A. Kharchilava, C. McLean, D. Nguyen, A. Parker, J. Pekkanen, S. Rappoccio, B. Roozbahani University of Mississippi, Oxford, U.S.A. J.G. Acosta, S. Oliveros University of Nebraska-Lincoln, Lincoln, U.S.A. K. Bloom, D.R. Claes, C. Fangmeier, L. Finco, F. Golf, R. Gonzalez Suarez, R. Kamalied- din, I. Kravchenko, J.E. Siado, G.R. Snow†, B. Stieger, W. Tabb – 45 – Princeton University, Princeton, U.S.A. Princeton University, Princeton, U.S.A. S. Cooperstein, G. Dezoort, P. Elmer, J. Hardenbrook, N. Haubrich, S. Higginbotham, A. Kalogeropoulos, S. Kwan, D. Lange, M.T. Lucchini, J. Luo, D. Marlow, K. Mei, I. Ojalvo, J. Olsen, C. Palmer, P. Pirou´e, J. Salfeld-Nebgen, D. Stickland, C. Tully, Z. Wang University of Puerto Rico, Mayaguez, U.S.A. S. Malik, S. Norberg Purdue University, West Lafayette, U.S.A. A. Barker, V.E. Barnes, S. Das, L. Gutay, M. Jones, A.W. Jung, A. Khatiwada, B. Ma- hakud, D.H. Miller, G. Negro, N. Neumeister, C.C. Peng, S. Piperov, H. Qiu, J.F. Schulte, J. Sun, F. Wang, R. Xiao, W. Xie Purdue University Northwest, Hammond, U.S.A. T. Cheng, J. Dolen, N. Parashar Rice University, Houston, U.S.A. Rice University, Houston, U.S.A. U. Behrens, K.M. Ecklund, S. Freed, F.J.M. Geurts, M. Kilpatrick, Arun Kumar, W. Li, B.P. Padley, R. Redjimi, J. Roberts, J. Rorie, W. Shi, A.G. Stahl Leiton, Z. Tu, A. Zhang University of Rochester, Rochester, U.S.A. The Ohio State University, Columbus, U.S.A. The Ohio State University, Columbus, U.S.A. J. Alimena, B. Bylsma, L.S. Durkin, S. Flowers, B. Francis, C. Hill, W. Ji, A. Lefeld, T.Y. Ling, B.L. Winer Northwestern University, Evanston, U.S.A. JHEP11(2019)109 S. Bhattacharya, J. Bueghly, T. Gunter, K.A. Hahn, N. Odell, M.H. Schmitt, K. Sung, M. Trovato, M. Velasco University of Notre Dame, Notre Dame, U.S.A. R. Bucci, N. Dev, R. Goldouzian, M. Hildreth, K. Hurtado Anampa, C. Jessop, D.J. Kar- mgard, K. Lannon, W. Li, N. Loukas, N. Marinelli, I. Mcalister, F. Meng, C. Mueller, Y. Musienko36, M. Planer, R. Ruchti, P. Siddireddy, G. Smith, S. Taroni, M. Wayne, A. Wightman, M. Wolf, A. Woodard Texas Tech University, Lubbock, U.S.A. N. Akchurin, J. Damgov, F. De Guio, S. Kunori, K. Lamichhane, S.W. Lee, T. Mengke, S. Muthumuni, T. Peltola, S. Undleeb, I. Volobouev, Z. Wang, A. Whitbeck Vanderbilt University, Nashville, U.S.A. Vanderbilt University, Nashville, U.S.A. S. Greene, A. Gurrola, R. Janjam, W. Johns, C. Maguire, A. Melo, H. Ni, K. Padeken, F. Romeo, P. Sheldon, S. Tuo, J. Velkovska, M. Verweij S. Greene, A. Gurrola, R. Janjam, W. Johns, C. Maguire, A. Melo, H. Ni, K. Padeken, F. Romeo, P. Sheldon, S. Tuo, J. Velkovska, M. Verweij S. Greene, A. Gurrola, R. Janjam, W. Johns, C. Magui F. Romeo, P. Sheldon, S. Tuo, J. Velkovska, M. Verweij University of Virginia, Charlottesville, U.S.A. M.W. Arenton, P. Barria, B. Cox, G. Cummings, R. Hirosky, M. Joyce, A. Ledovskoy, C. Neu, B. Tannenwald, Y. Wang, E. Wolfe, F. Xia Wayne State University, Detroit, U.S.A. R. Harr, P.E. Karchin, N. Poudyal, J. Sturdy, P. Thapa University of Wisconsin - Madison, Madison, WI, U.S.A. T. Bose, J. Buchanan, C. Caillol, D. Carlsmith, S. Dasu, I. De Bruyn, L. Dodd, F. Fiori, 77 C. Galloni, B. Gomber77, H. He, M. Herndon, A. Herve, U. Hussain, P. Klabbers, A. Lanaro, A. Loeliger, K. Long, R. Loveless, J. Madhusudanan Sreekala, T. Ruggles, A S i V Sh W H S i h D T S T b h i h N W d A. Lanaro, A. Loeliger, K. Long, R. Loveless, J. Madhusudanan Sreekala, T. Ruggles, A. Savin, V. Sharma, W.H. Smith, D. Teague, S. Trembath-reichert, N. University of Rochester, Rochester, U.S.A. Bodek, P. de Barbaro, R. Demina, J.L. Dulemba, C. Fallon, T. Ferbel, M. Galanti, A. Bodek, P. de Barbaro, R. Demina, J.L. Dulemba, C. Fallon, T. Ferbel, M. Galanti, A. Garcia-Bellido, O. Hindrichs, A. Khukhunaishvili, E. Ranken, P. Tan, R. Taus A. Garcia-Bellido, O. Hindrichs, A. Khukhunaishvili, E. Ranken, P. Tan, R. Taus – 46 – Rutgers, The State University of New Jersey, Piscataway, U.S.A. B. Chiarito, J.P. Chou, A. Gandrakota, Y. Gershtein, E. Halkiadakis, A. Hart, M. Heindl, E. Hughes, S. Kaplan, S. Kyriacou, I. Laflotte, A. Lath, R. Montalvo, K. Nash, M. Osher- son, H. Saka, S. Salur, S. Schnetzer, S. Somalwar, R. Stone, S. Thomas Rutgers, The State University of New Jersey, Piscataway, U.S.A. University of Tennessee, Knoxville, U.S.A. H. Acharya, A.G. Delannoy, G. Riley, S. Spanier University of Tennessee, Knoxville, U.S.A. H. Acharya, A.G. Delannoy, G. Riley, S. Spanier Texas A&M University, College Station, U.S.A. Texas A&M University, College Station, U.S.A. O. Bouhali75, M. Dalchenko, M. De Mattia, A. Delgado, S. Dildick, R. Eusebi, J. Gilmore, O. Bouhali75, M. Dalchenko, M. De Mattia, A. Delgado, S. Dildick, R. Eusebi, J. Gilmore, O. Bouhali75, M. Dalchenko, M. De Mattia, A. Delgado, S. Dildick, R. Eusebi, J. Gilmore, T Huang T Kamon76 S Luo D Marley R Mueller D Overton L Perni`e D Rathjens T. Huang, T. Kamon76, S. Luo, D. Marley, R. Mueller, D. Overton, L. Perni`e, D. Rathjens, A. Safonov JHEP11(2019)109 Texas Tech University, Lubbock, U.S.A. Texas Tech University, Lubbock, U.S.A. Woods †: Deceased † 1: Also at Vienna University of Technology, Vienna, Austria 1: Also at Vienna University of Technology, Vienna, Austria 2: Also at IRFU, CEA, Universit´e Paris-Saclay, Gif-sur-Yvette, France 2: Also at IRFU, CEA, Universit´e Paris-Saclay, Gif-sur-Yvette, France 3: Also at Universidade Estadual de Campinas, Campinas, Brazil 3: Also at Universidade Estadual de Campinas, Campinas, Brazil 4: Also at Federal University of Rio Grande do Sul, Porto Alegre, Brazil 4: Also at Federal University of Rio Grande do Sul, Porto Alegre, 4: Also at Federal University of Rio Grande 5: Also at UFMS, Nova Andradina, Brazil 6: Also at Universidade Federal de Pelotas, Pelotas, Brazil 6: Also at Universidade Federal de Pelotas, Pelotas, Brazil 7: Also at Universit´e Libre de Bruxelles, Bruxelles, Belgium 7: Also at Universit´e Libre de Bruxelles, Bruxelles, Belgium 8: Also at University of Chinese Academy of Sciences, Beijing, China 8: Also at University of Chinese Academy of Sciences, Beijing, China 9: Also at Institute for Theoretical and Experimental Physics named by A.I. Alikhanov of NRC ‘Kurchatov Institute’, Moscow, Russia 10: Also at Joint Institute for Nuclear Research, Dubna, Russia 10: Also at Joint Institute for Nuclear Research, Dubna, Russia 11: Also at Ain Shams University, Cairo, Egypt 11: Also at Ain Shams University, Cairo, Egypt 12: Also at Zewail City of Science and Technology, Zewail, Egypt 12: Also at Zewail City of Science and Technology, Zewail, Egypt – 47 – 13: Also at Purdue University, West Lafayette, U.S.A. 14: Also at Universit´e de Haute Alsace, Mulhouse, France 15: Also at Erzincan Binali Yildirim University, Erzincan, Turkey 16: Also at CERN, European Organization for Nuclear Research, Geneva, Switzerland 17: Also at RWTH Aachen University, III. Texas Tech University, Lubbock, U.S.A. Physikalisches Institut A, Aachen, Germany 18: Also at University of Hamburg, Hamburg, Germany 19: Also at Brandenburg University of Technology, Cottbus, Germany 20: Also at Institute of Physics, University of Debrecen, Debrecen, Hungary, Debrecen, Hungary 21: Also at Institute of Nuclear Research ATOMKI, Debrecen, Hungary 1: Also at Institute of Nuclear Research ATOMK 22: Also at MTA-ELTE Lend¨ulet CMS Particle and Nuclear Physics Group, E¨otv¨os Lor´and University, Budapest, Hungary, Budapest, Hungary 22: Also at MTA-ELTE Lend¨ulet CMS Particle and Nuclear Physics Group, E¨otv¨os Lor´and U i it B d t H B d t H 22: Also at MTA-ELTE Lend¨ulet CMS Particle and Nuclear Physics Group, E¨otv¨os Lor´and University, Budapest, Hungary, Budapest, Hungary JHEP11(2019)109 23: Also at IIT Bhubaneswar, Bhubaneswar, India, Bhubaneswar, India 23: Also at IIT Bhubaneswar, Bhubaneswar, India, Bhubaneswar, India 24: Also at Institute of Physics, Bhubaneswar, India 25: Also at Shoolini University, Solan, India 26: Also at University of Visva-Bharati, Santiniketan, India 26: Also at University of Visva-Bharati, Santiniketan, India 27: Also at Isfahan University of Technology, Isfahan, Iran 27: Also at Isfahan University of Technology, Isfahan, Iran 28: Now at INFN Sezione di Bari a, Universit`a di Bari b, Politecnico di Bari c, Bari, Ita 28: Now at INFN Sezione di Bari a, Universit`a di Bari b, Politecnico di Bari c, Bari, Italy 29: Also at Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Bologna, Italy 29: Also at Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Bologna, Italy 30: Also at Centro Siciliano di Fisica Nucleare e di Struttura Della Materia, Catania, Italy 30: Also at Centro Siciliano di Fisica Nucleare e di Struttura Della Materia, Catania, I 31: Also at Scuola Normale e Sezione dell’INFN, Pisa, Italy 31: Also at Scuola Normale e Sezione dell’INFN, Pisa, Italy 32: Also at Riga Technical University, Riga, Latvia, Riga, Latvia 32: Also at Riga Technical University, Riga, Latvia, Riga, Latvia 33: Also at Malaysian Nuclear Agency, MOSTI, Kajang, Malaysia 34: Also at Consejo Nacional de Ciencia y Tecnolog´ıa, Mexico City, Mexico 34: Also at Consejo Nacional de Ciencia y Tecnolog´ıa, Mexico City, Mexico 35: Also at Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland 35: Also at Warsaw University of Technology, Institute of Ele 35: Also at Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland at Institute for Nuclear Research, Moscow, Russ 37: Now at National Research Nuclear University ’Moscow Engineering Physics Institute’ (MEPhI), Moscow, Russia 37: Now at National Research Nuclear University ’Moscow Engineering Physics Institute’ (MEPhI), Moscow, Russia 38: Also at St. Texas Tech University, Lubbock, U.S.A. Petersburg State Polytechnical University, St. Petersburg, Russia 38: Also at St. Petersburg State Polytechnical University, St. Petersburg, Russia 39: Also at University of Florida, Gainesville, U.S.A. 40: Also at Imperial College, London, U.K. 41: Also at P.N. Lebedev Physical Institute, Moscow, Russia 41: Also at P.N. Lebedev Physical Institute, Moscow, Russia 42: Also at California Institute of Technology, Pasadena, U.S.A. 42: Also at California Institute of Technology, Pasadena, U.S.A. 43: Also at Budker Institute of Nuclear Physics, Novosibirsk, Russia 43: Also at Budker Institute of Nuclear Physics, Novosibirsk, Russia Also at Budker Institute of Nuclear Physics, Nov 44: Also at Faculty of Physics, University of Belgrade, Belgrade, Serbia 44: Also at Faculty of Physics, University of Belgrade, Belgrade, Serbia 45: Also at Universit`a degli Studi di Siena, Siena, Italy 46: Also at INFN Sezione di Pavia a, Universit`a di Pavia b, Pavia, Italy, Pavia, Italy 46: Also at INFN Sezione di Pavia a, Universit`a di Pavia b, Pavia, Italy, Pavia, Italy 47: Also at National and Kapodistrian University of Athens, Athens, Greece 48: Also at Universit¨at Z¨urich, Zurich, Switzerland 49: Also at Stefan Meyer Institute for Subatomic Physics, Vienna, Austria, Vienna, Austria 50: Also at Burdur Mehmet Akif Ersoy University, BURDUR, Turkey 51: Also at Adiyaman University, Adiyaman, Turkey 52: Also at S¸ırnak University, Sirnak, Turkey 53: Also at Beykent University, Istanbul, Turkey, Istanbul, Turkey 53: Also at Beykent University, Istanbul, Turkey, Istanbul, Turkey 54: Also at Istanbul Aydin University, Istanbul, Turkey 54: Also at Istanbul Aydin University, Istanbul, Turkey 55: Also at Mersin University, Mersin, Turkey 56: Also at Piri Reis University, Istanbul, Turkey 57: Also at Gaziosmanpasa University, Tokat, Turkey – 48 – 58: Also at Ozyegin University, Istanbul, Turkey 58: Also at Ozyegin University, Istanbul, Turkey 59: Also at Izmir Institute of Technology, Izmir, Turkey 59: Also at Izmir Institute of Technology, Izmir, Turkey 60: Also at Marmara University, Istanbul, Turkey 60: Also at Marmara University, Istanbul, Turkey 61: Also at Kafkas University, Kars, Turkey 62: Also at Istanbul Bilgi University, Istanbul, Turkey 62: Also at Istanbul Bilgi University, Istanbul, Turkey 63: Also at Hacettepe University, Ankara, Turkey 63: Also at Hacettepe University, Ankara, Turkey 64: Also at Vrije Universiteit Brussel, Brussel, Belgium 64: Also at Vrije Universiteit Brussel, Brussel, Belgium 65: Also at School of Physics and Astronomy, University of Southampton, Southampton, U.K. 65: Also at School of Physics and Astronomy, University of Southampton, Southampton, U.K. Texas Tech University, Lubbock, U.S.A. 65: Also at School of Physics and Astronomy, University of Southamp Also at IPPP Durham University, Durham, U.K 67: Also at Monash University, Faculty of Science, Clayton, Australi 67: Also at Monash University, Faculty of Science, Clayton, Australia JHEP11(2019)109 69: Also at Karamano˘glu Mehmetbey University, Karaman, Turkey 69: Also at Karamano˘glu Mehmetbey University, Karaman, Turkey 70: Also at Vilnius University, Vilnius, Lithuania 70: Also at Vilnius University, Vilnius, Lithuania 71: Also at Bingol University, Bingol, Turkey 71: Also at Bingol University, Bingol, Turkey 72: Also at Georgian Technical University, Tbilisi, Georgia 72: Also at Georgian Technical University, Tbilisi, Georgia 72: Also at Georgian Technical University, T 73: Also at Sinop University, Sinop, Turkey 73: Also at Sinop University, Sinop, Turkey 74: Also at Mimar Sinan University, Istanbul, Istanbul, Turkey 74: Also at Mimar Sinan University, Istanbu 74: Also at Mimar Sinan University, Istanbul, Istanbul, Turkey 75: Also at Texas A&M University at Qatar, Doha, Qatar 75: Also at Texas A&M University at Qatar, Doha, Qatar 76: Also at Kyungpook National University, Daegu, Korea, Daegu, Korea 76: Also at Kyungpook National University, Daegu, Korea, Daegu, Korea 77: Also at University of Hyderabad, Hyderabad, India 77: Also at University of Hyderabad, Hyderabad, India – 49 –
https://openalex.org/W3095336760
https://mediatum.ub.tum.de/doc/1624527/document.pdf
English
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Oxytocin Shapes Spontaneous Activity Patterns in the Developing Visual Cortex by Activating Somatostatin Interneurons
CB/Current biology
2,021
cc-by
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In Brief Maldonado etal. uncover oxytocin’s rolein developing sensory cortices. In vivo, they show that oxytocin decreases the frequency and correlations of spontaneous activity patterns in V1 by specifically activating somatostatin+ interneurons. In S1, oxytocin increases both excitation and inhibition and does not affect spontaneous activity frequency. Article Article Paloma P. Maldonado, Alvaro Nuno-Perez, Jan H. Kirchner, Elizabeth Hammock, Julijana Gjorgjieva, Christian Lohmann Correspondence c.lohmann@nin.knaw.nl (C.L.) Correspondence c.lohmann@nin.knaw.nl (C.L.) Oxytocin Shapes Spontaneous Activity Patterns in the Developing Visual Cortex by Activating Somatostatin Interneurons Maldonado et al., 2021, Current Biology 31, 322–333 January 25, 2021 ª 2020 The Author(s). Published by Elsevier Inc. https://doi.org/10.1016/j.cub.2020.10.028 Authors Graphical Abstract Paloma P. Maldonado, Alvaro Nuno-Perez, Jan H. Kirchner, Elizabeth Hammock, Julijana Gjorgjieva, Christian Lohmann SUMMARY Spontaneous network activity shapes emerging neuronal circuits during early brain development prior to sensory perception. However, how neuromodulation influences this activity is not fully understood. Here, we report that the neuromodulator oxytocin differentially shapes spontaneous activity patterns across sen- sory cortices. In vivo, oxytocin strongly decreased the frequency and pairwise correlations of spontaneous activity events in the primary visual cortex (V1), but it did not affect the frequency of spontaneous network events in the somatosensory cortex (S1). Patch-clamp recordings in slices and RNAscope showed that oxytocin affects S1 excitatory and inhibitory neurons similarly, whereas in V1, oxytocin targets only inhibitory neurons. Somatostatin-positive (SST+) interneurons expressed the oxytocin receptor and were activated by oxytocin in V1. Accordingly, pharmacogenetic silencing of V1 SST+ interneurons fully blocked oxytocin’s ef- fect on inhibition in vitro as well its effect on spontaneous activity patterns in vivo. Thus, oxytocin decreases the excitatory/inhibitory (E/I) ratio by recruiting SST+ interneurons and modulates specific features of V1 spontaneous activity patterns that are crucial for the wiring and refining of developing sensory circuits. 8Lead Contact 8Lead Contact *Correspondence: p.maldonado@nin.knaw.nl (P.P.M.), alvaro.nunoperez@unil.ch (A.N.-P.), jan.kirchner@brain.mpg.de (J.H.K.), hammock@ psy.fsu.edu (E.H.), gjorgjieva@brain.mpg.de (J.G.), c.lohmann@nin.knaw.nl (C.L.) https://doi.org/10.1016/j.cub.2020.10.028 Article Oxytocin Shapes Spontaneous Activity Patterns in the Developing Visual Cortex by Activating Somatostatin Interneurons Paloma P. Maldonado,1 Alvaro Nuno-Perez,1,7 Jan H. Kirchner,3,4 Elizabeth Hammock,5,6 Julijana Gjorgjieva,3,4 and Christian Lohmann1,2,8,* 1Department of Synapse and Network Development, Netherlands Institute for Neuroscience, 1105 BA Amsterdam, the Netherlands 2Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, 1081 HV Amsterdam, the Netherlands 3Max Planck Institute for Brain Research, Computation in Neural Circuits, 60438 Frankfurt am Main, Germany 4TUM School of Life Sciences, Technical University of Munich, 85354 Freising, Germany 5Program in Neuroscience, The Florida State University, Tallahassee, FL 32306, USA 6Department of Psychology, The Florida State University, Tallahassee, FL 32306, USA 7Present address: The Department of Fundamental Neuroscience, The University of Lausanne, Rue du Bugnon 9, Lausanne 1005, Switzerland 8Lead Contact ll OPEN ACCESS ll OPEN ACCESS 322 Current Biology 31, 322–333, January 25, 2021 ª 2020 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Paloma P. Maldonado,1 Alvaro Nuno-Perez,1,7 Jan H. Kirchner,3,4 Elizabeth Hammock,5,6 Julijana Gjorgjieva,3,4 and Christian Lohmann1 2 8 * Paloma P. Maldonado,1 Alvaro Nuno-Perez,1,7 Jan H. Kirchner,3,4 Elizabeth Hammock,5,6 Julijana Gjorgjieva,3,4 and Christian Lohmann1,2,8,* 1Department of Synapse and Network Development, Netherlands Institute for Neuroscience, 1105 BA Amsterdam, the Netherlands 2Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, 1081 HV Amsterdam, 1Department of Synapse and Network Development, Netherlands Institute for Neuroscience, 1105 BA Amsterdam, the Netherlands 2Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, 1081 HV Amsterdam the Netherlands 5Program in Neuroscience, The Florida State University, Tallahassee, FL 32306, USA 6D t t f P h l Th Fl id St t U i it T ll h FL 32306 USA *Correspondence: p.maldonado@nin.knaw.nl (P.P.M.), alvaro.nunoperez@unil.ch (A.N.-P.), jan.kirchner@brain.mpg.de (J.H.K.), hammock@ psy.fsu.edu (E.H.), gjorgjieva@brain.mpg.de (J.G.), c.lohmann@nin.knaw.nl (C.L.) https://doi.org/10.1016/j.cub.2020.10.028 Highlights d Oxytocin modulates spontaneous activity event patterns in the developing V1 d Oxytocin increases inhibition by activating somatostatin+ interneurons d SST+ neuron activity reduces event frequency and correlations, but not amplitude d In S1, oxytocin increases excitation and inhibition and does not modulate frequency ll ll Figure 1. Oxytocin Affects Spontaneous Network Events Differentially across Sensory Cortices 0 2 4 1 3 5 6 V1 S1 in vivo calcium imaging in lightly anesthetized pups between postnatal days (P) 9 and 13. We observed spontaneous network activity in V1, S1, and higher visual areas (Figures 1A and 1B). Frequently, network events were confined to in- dividual sensory regions but sometimes occurred across the entire field of view. After topical appli- cation of oxytocin (1 mM) onto the cortical surface (for details, see STAR Methods), the occurrence of network events was strongly decreased in V1 but only modestly changed in S1 (Figures 1A–1D). Control appli- cation of cortex buffer without oxytocin did not change the fre- quency of calcium events (V1 mean frequency before cortex buffer 0.042 ± 0.002 Hz; after 0.044 ± 0.004 Hz; p > 0.05; n = 4; Wilcoxon test. S1 mean frequency before cortex buffer 0.042 ± 0.003 Hz; after 0.044 ± 0.004 Hz; p > 0.05; n = 4; Wil- coxon test). Surprisingly, the response of V1 and S1 differed significantly (percentage of change V1: 43.5% ± 7.9%; S1: 7.9% ± 5.2%; p = 0.0026; n = 7; unpaired two-tailed t test). Network event area, amplitude, or duration was not affected (Figures 1E–1G). 0 2 4 3 5 6 V1 S1 in vivo calcium imaging in lightly anesthetized pups between postnatal days (P) 9 and 13. We observed spontaneous network activity in V1, S1, and higher visual areas (Figures 1A and 1B). Frequently, network events were confined to in- dividual sensory regions but sometimes occurred across the entire field of view. After topical appli- cation of oxytocin (1 mM) onto the cortical surface (for details, see STAR Methods), the occurrence of network events was strongly decreased in V1 but only modestly changed in S1 (Figures 1A–1D). Control appli- cation of cortex buffer without oxytocin did not change the fre- quency of calcium events (V1 mean frequency before cortex buffer 0.042 ± 0.002 Hz; after 0.044 ± 0.004 Hz; p > 0.05; n = 4; Wilcoxon test. S1 mean frequency before cortex buffer 0.042 ± 0.003 Hz; after 0.044 ± 0.004 Hz; p > 0.05; n = 4; Wil- coxon test). Surprisingly, the response of V1 and S1 differed significantly (percentage of change V1: 43.5% ± 7.9%; S1: 7.9% ± 5.2%; p = 0.0026; n = 7; unpaired two-tailed t test). Network event area, amplitude, or duration was not affected (Figures 1E–1G). INTRODUCTION During the period when synaptic connections are shaped by spontaneous activity, neuromodulators play an important role in the development of cortical circuits.12–14 One of them, oxytocin, is particularly prominently expressed in sensory cortices during the first 2 postnatal weeks and decreases there- after until the end of the 3rd postnatal week, when it reaches adult levels.15 Similarly, oxytocin receptor ligand binding, immunolab- eling, and mRNA expression in sensory cortices peak during the 2nd postnatal week and decrease thereafter.15–17 Thus, oxytocin is most likely required for the development of sensory circuits during the 1st postnatal weeks in addition to its roles in social sensory processing in adults, where oxytocin increases the sensitivity of auditory cortex neurons to pup calls,18 modulates odor processing in the olfactory and accessory systems,19 and shapes social sensory perception.20,21 Oxytocin modulates syn- aptic transmission in the developing forebrain. For example, oxytocin is required for cross-modal, experience-driven synaptic plasticity in the somatosensory cortex during the first 2 weeks of life.15 Moreover, oxytocin triggers a temporary switch of In the developing brain, neuronal connections form with remark- able precision. First, axons grow to predetermined target areas guided by molecular cues. Subsequently, activity-dependent processes refine synaptic connections:1–3 already before the senses become active, spontaneous activity drives synaptic refinement to prepare the brain for interacting with the outside world. Finally, circuits adapt to the prevalent environ- mental conditions through sensory-experience-driven plasticity mechanisms. Spontaneous activity is expressed in specific patterns, and these patterns are crucial for the appropriate wiring of neurons. For example, in the developing retina, waves of spontaneous ac- tivity travel at specific speeds, in various directions, and with different wave front shapes.4,5 Retinal waves drive highly struc- tured activity patterns in the central visual system, including the primary visual cortex.6–8 Perturbing these activity patterns leads to miswiring of the central visual system.9–11 ll OPEN ACCESS hippocampal GABA receptor action from excitatory to inhibi- tory.12,22 However, it has been unclear whether spontaneous activity patterns, which drive synaptic plasticity before experi- ence-driven refinement occurs,23 are regulated by oxytocin as well. Oxytocin Desynchronizes Spontaneous V1 Network Activity To evaluate how oxytocin modulates the activity of individual neurons in the developing cortical network, we performed in vivo two-photon calcium imaging in V1 of lightly anesthetized neonatal mice. Layer 2/3 cells were labeled with the calcium in- dicator Oregon Green BAPTA-1 (OGB-1) by bolus loading.24 Oxytocin application decreased the frequency of calcium events transiently (Figures 2A–2C) without affecting their ampli- tude (Figure 2D), in line with our wide-field experiments. In con- trol experiments, where we applied cortex buffer without oxytocin, frequency and amplitude were unaffected (Figures S1A and S1B). Figure 1. Oxytocin Affects Spontaneous Network Events Differentially across Sensory Cortices 0 20 40 60 80 V1 S1 Amplitude (%∆F/F0) 0 20 40 60 80 V1 S1 ( ) Oxt 20 40 60 0 50 75 100 0 Time (min) 25 F Amplitude (%∆F/F0) Amplitude (%∆F/F0) 0 Duration (s) 2 4 1 3 5 6 V1 S1 Oxt Duration (s) 2 4 1 3 5 0 6 50 75 100 0 Time (min) 25 G Oxt 20 40 60 0 50 75 100 0 Time (min) 25 F Amplitude (%∆F/F0) G F Duration (s) hippocampal GABA receptor action from excitatory to inhibi- tory.12,22 However, it has been unclear whether spontaneous activity patterns, which drive synaptic plasticity before experi- ence-driven refinement occurs,23 are regulated by oxytocin as well. Here, we asked whether oxytocin signaling shapes neuronal activity patterns in the primary visual (V1) and somatosensory cortices (S1) during the 2nd postnatal week. We found that, while in S1, oxytocin activates inhibitory and excitatory neurons simi- larly and does not affect the frequency of network activity, in V1, oxytocin recruits specifically somatostatin-expressing (SST+) interneurons to control network activity frequency and correlation, properties known to determine the refinement of synaptic connections in V1 prior to eye opening. Figure 1. Oxytocin Affects Spontaneous Network Events Differentially across Sensory Cortices A A (A) Wide-field calcium imaging of spontaneous activity in V1 and S1 before eye opening. (Left) Single-frame images depict network events activating V1 and/or S1 during baseline recordings before oxytocin application. (Right) Network events after oxytocin (Oxt) application are shown. (B) Traces show fluorescent changes in V1 and S1 before and after oxytocin application. (C) Superimposition of all network events detected during a 5-min baseline recording (left) and after oxytocin application (right). Color code indicates the frequency of the detected events. V1 activity is strongly reduced. C (D) Network event frequency in V1 and S1 during baseline and after oxytocin application. Time courses represent 5- min averages. The horizontal bars above the line plots indicate the time points when the values for each time bin differed significantly from baseline (dark shades; paired two-tailed t test; p < 0.05; without multi-measurement correction). *p = 0.016 (n = 7 animals; Wilcoxon test). hippocampal GABA receptor action from excitatory to inhibi- V1 S1 0 20 40 60 80 Frequency (Hz) 6 2 4 8 0 * V1 S1 Baseline Oxt Oxt 6 2 4 Frequency (Hz) 0 75 50 100 0 S1 V1 Time (min) 25 Oxt 20 40 60 0 50 75 100 0 Time (min) 25 0 0 0.8 0.4 2 1.2 1.6 Duration (s) 2 4 1 3 5 6 V1 S1 V1 S1 2 Area (mm ) Oxt 0.8 0.4 0 2 2 Area (mm ) 1.2 1.6 50 100 0 Time (min) 25 75 Oxt Duration (s) 2 4 1 3 5 0 6 50 75 100 0 Time (min) 25 D E F G Amplitude (%∆F/F0) Amplitude (%∆F/F0) -2 x10 -2 x10 but only mod V1 S1 Frequency (Hz) 6 2 4 8 0 * Baseline Oxt 0 0.8 0.4 2 1.2 1.6 V1 S1 2 Area (mm ) Oxt 0.8 0.4 0 2 2 Area (mm ) 1.2 1.6 50 100 0 Time (min) 25 75 E -2 x10 Oxt 6 2 4 Frequency (Hz) 0 75 50 100 0 S1 V1 Time (min) 25 D -2 x10 D (E) Network event area. Frequency (Hz) (F) Network event amplitude. (F) Network event amplitude. (G) Network event duration. (G) Network event duration. Data are represented as mean ± SEM. See also Figure S6. Data are represented as mean ± SEM. See also Figure S6. INTRODUCTION Here, we asked whether oxytocin signaling shapes neuronal Baseline Oxt 0 0.03 Hz Baseline Oxt V1 S1 20 280 0 180 -10 270 50 s 50% ΔF/F0 Visual cortex Somatosensory cortex Baseline Oxt V1 S1 0 20 40 60 80 Frequency (Hz) 6 2 4 8 0 * V1 S1 Baseline Oxt Oxt 6 2 4 Frequency (Hz) 0 75 50 100 0 S1 V1 Time (min) 25 Oxt 20 40 60 0 50 75 100 0 Time (min) 25 0 0 0.8 0.4 2 1.2 1.6 Duration (s) 2 4 1 3 5 6 V1 S1 V1 S1 2 Area (mm ) Oxt 0.8 0.4 0 2 2 Area (mm ) 1.2 1.6 50 100 0 Time (min) 25 75 Oxt Duration (s) 2 4 1 3 5 0 6 50 75 100 0 Time (min) 25 A B C D E F G Amplitude (%∆F/F0) Amplitude (%∆F/F0) %∆F/F0 %∆F/F0 %∆F/F0 0.5 mm -2 x10 -2 x10 but only mod cation of cort quency of ca buffer 0.042 4; Wilcoxon 0.042 ± 0.003 Article Baseline Oxt 0 0.03 Hz 50 s 50% ΔF/F0 Visual cortex Somatosensory cortex Baseline Oxt B C Baseline Oxt V1 S1 20 280 0 180 -10 270 A %∆F/F0 %∆F/F0 %∆F/F0 0.5 mm B Figure 1. Oxytocin Affects Spontaneous Network Events Differentially across Sensory Cortices Oxytocin Modulates Spontaneous Cortical Activity Differentially across Sensory Areas Again, we observed that oxytocin, but not cortex buffer application, strongly decreased correlations across the entire population. There were essentially no neuronal pairs that showed increased correlations (Figure S1C). We further found that oxytocin had a subtractive effect on neuronal correlations (Figures 2G and 2H), such that more distal pairs of neurons were proportionally decorrelated more strongly by oxytocin than nearby neuronal pairs (Figures 2I and 2J). Finally, we investigated whether the changes in correlations between all neurons occurred uniformly or whether specific pairs of neurons underwent changes in their correlations. To address this question, we first computed the correlation matrices at different time points (Figure 2K). Interest- ingly, we saw that, during late oxytocin, when the frequency of calcium events had returned to baseline (mean baseline: 0.032 ± 0.004 Hz; mean 125–135 min: 0.027 ± 0.003 Hz; p = 0.14; paired two-tailed t test), the correlation matrices exhibited sustained structural differences in the correlational structure of subsets of cells (Figure 2K, inset). To quantify these differences, we computed the mean squared distance (MSD) between the baseline matrix and the matrices computed at varying time points and found that networks treated with oxytocin exhibited a sustained higher distance compared to baseline (p = 0.038, repeated-measures one-way ANOVA; mean baseline: 0.1 ± 0.04; mean 60–70 min: 6.36 ± 1.56, p = 0.007; mean 90– 100 min: 4.52 ± 1.12, p = 0.008; mean 125–135 min: 2.94 ± 0.6, p = 0.009; post hoc paired two-tailed t test). Conversely, the MSD was unchanged with cortex buffer application (p = 0.19; repeated-measures one-way ANOVA; Figure 2L). These oxytocin-induced changes in network activity patterns may reflect differences in functional connectivity between the imaged neurons or their shared inputs, because response correlations are indicative of strong synaptic connections in the adult and probably common feedforward inputs in the developing visual cortex.26,27 In contrast to V1, in S1, oxytocin bath application increased sEPSC frequency in layer 2/3 pyramidal cells (Figures 4H and 4I). Again, sEPSC amplitude was unaffected (Figure 4J). The fre- quency of sIPSCs was increased but less pronounced than in V1 (Figures 4K and 4L); amplitudes were unaffected (Figure 4M). Thus, oxytocin shifted the E/I ratio in V1 toward inhibition (Fig- ure 4G; p < 0.001; repeated-measurement two-way ANOVA) but did not affect E/I significantly in S1 (Figure 4N). Oxytocin Modulates Spontaneous Cortical Activity Differentially across Sensory Areas To study the role of the neuromodulator oxytocin in developing sensory cortices, we first asked whether oxytocin receptor acti- vation modulates large-scale spontaneous activity patterns. We used in utero electroporation to express the calcium sensor GCaMP6s in layer 2/3 pyramidal cells across V1, higher visual areas, and the barrel cortex. Then, we performed wide-field Current Biology 31, 322–333, January 25, 2021 323 A i l Article ll OPEN ACCESS oxytocin receptor expression on the cellular level could explain oxytocin’s differential effect in these areas. To test this idea func- tionally, we examined how oxytocin regulated excitatory and inhibitory synaptic transmission in V1 and S1. Whole-cell patch-clamp recordings of layer 2/3 pyramidal neurons in slices from V1 showed that oxytocin affected neither the frequency nor the amplitude of spontaneous excitatory postsynaptic currents (sEPSCs) (Figures 4A–4C). Next, we measured spontaneous inhibitory postsynaptic currents (sIPSCs) at the reversal potential of glutamate-receptor-mediated currents. We found that the fre- quency of sIPSCs, in contrast to that of sEPSCs, was strongly increased after oxytocin bath application (Figures 4D and 4E). The amplitude of sIPSCs was unaffected (Figure 4F). To test whether this increase in frequency was mediated by the specific activation of the oxytocin and not the vasopressin 1A receptor,28 which can be activated by oxytocin as well,29 we blocked the oxytocin receptor using its specific antagonist OTA.30 OTA pre- vented the oxytocin-mediated increase in sIPSC frequency entirely (fold-change oxytocin only, Figure 4E: 4.95 ± 1.53; oxytocin + OTA, Figure S2: 0.98 ± 0.32; p = 0.012; unpaired two-tailed Mann-Whitney test), demonstrating that this effect was mediated by the oxytocin receptor. Thus, activation of the oxytocin receptor increased the inhibitory tone in V1 dramatically but did not affect excitatory synaptic transmission. Because the correlational structure of spontaneous network activity determines its role in network refinement,25 we also investigated whether oxytocin affected the pairwise correlations between spontaneously active neurons. We observed that oxytocin application decreased the mean Pearson correlation coefficients across pairs of neurons (Figures 2E and 2F), whereas cortex buffer applications did not affect such correla- tions (Figures 2E and 2F). Next, we explored changes in correla- tions at the level of individual neurons after oxytocin application in more detail. We plotted pairwise correlations for all experi- ments during baseline against the correlations after oxytocin or cortex buffer application (Figures S1C and S1D). Oxytocin Targets SST+ Interneurons in the Developing V1 Because we observed that oxytocin shaped spontaneous activ- ity patterns effectively in V1, but not in S1, we focused next on the cellular mechanism of oxytocin-mediated facilitation of inhi- bition in V1. First, we measured miniature IPSCs (mIPSCs) before and after oxytocin bath application and found that mIPSC fre- quency and amplitude were unaffected by oxytocin (Figures 5A–5C). This indicated that the number of inhibitory synapses, the density of postsynaptic receptors, or changes in the presyn- aptic release machinery could not explain the increase in sIPSC frequency described above. Oxytocin Modulates Spontaneous Cortical Activity Differentially across Sensory Areas These exper- iments suggested that differences in the magnitude of inhibitory versus excitatory synaptic activity modulation accounted for the differences in the effect of oxytocin on spontaneous network ac- tivity in V1 versus S1. Oxytocin Targets SST+ Interneurons in the Developing V1 Sensory Areas To search for alternative causes of the increased inhibitory ac- tivity, we performed voltage-clamp recordings in inhibitory inter- neurons. We used two mouse lines expressing TdTomato to target inhibitory neurons in general (GAD2-Cre;Rosa26-TdTo- mato) or somatostatin-expressing interneurons specifically (SST-Cre;Rosa26-TdTomato). We focused on SST+ interneu- rons for four reasons: (1) RNA sequencing (RNA-seq) data in adulthood showed that V1 oxytocin receptors are expressed pri- marily in SST+ interneurons (Figure S3A; Allen Brain Atlas data portal: http://casestudies.brain-map.org/celltax).31 (2) We found To investigate whether the differential modulation of V1 and S1 by oxytocin as described above (Figure 1) can be explained by differences in the distribution of the oxytocin receptor in these areas, we used RNAscope to detect Oxtr, Scl17a7 (coding for VGLUT1), and Gad1 mRNA in the cortex at P10. We found that Oxtr was expressed in V1 as well as in S1 (Figure 3). However, in V1, Oxtr co-localized almost exclusively with the Gad1 signal (Figures 3B–3D), whereas in S1, the Oxtr signal co-localized with both the VGLUT1 and Gad1 signal (Figures 3F–3H). These observations suggested that differences between V1 and S1 in 324 Current Biology 31, 322–333, January 25, 2021 ll OPEN ACCESS Pairwise correlation ** 0 0.2 0.4 0.6 0.8 0 0.2 0.4 0.6 0.8 Pairwise correlation F Baseline Oxt Oxt -2 x10 A B 20 s 10% ΔF/F0 0 5 10 15 20 25 Baseline Oxt Amplitude (%∆F/F0) 1' 2' 3' 40 μm 1 2 3 whole field 1 2 3 0 25 50 75 100 1 2 3 4 Frequency (Hz) Oxt C 0 2 4 6 -2 x10* Frequency (Hz) 125 0 Time (min) Time (min) whole field 1 2 3 K 0 0 25 50 75 100 12 16 20 4 8 D Amplitude (%∆F/F0) 0 125 300 200 100 150 50 % change in correlation Distance (μm) 0 200 100 Corr 0.01 I 300 200 100 150 50 % change in correlation Distance (μm) 0 200 100 Corr -0.32 J Distance vs. Figure 2. Oxytocin Desynchronizes Network Activity in V1 B A (A and B) V1 network activity before and after oxytocin application. (Left) Layer 2/3 neurons labeled with the calcium indicator Oregon Green- BAPTA 1 are shown. Traces show fluorescent changes of three example neurons and the average activity across all cells. (C) Network event frequency during baseline and after oxytocin application. Imaging resumed approximately 10 min after oxytocin application. The frequency of network events was reduced after oxytocin application. The horizontal bar indicates significant deviations from baseline as in Figure 1 (dark shades; paired two-tailed t test; p < 0.05; without multi-measurement correction). *p = 0.015 (n = 8 animals; paired two-tailed t test). (D) Network event amplitude during baseline and after oxytocin application. Oxt 20 s 0 5 10 15 20 25 Baseline Oxt Amplitude (%∆F/F0) Time (min) 0 25 50 75 100 12 16 20 4 8 D Amplitude (%∆F/F0) 0 125 -2 x10 0 25 50 75 100 1 2 3 4 Frequency (Hz) Oxt C 0 2 4 6 -2 x10* Frequency (Hz) 125 0 Time (min) D C (E) Time course of pairwise Pearson correlation co- efficients before and after oxytocin and cortex buffer application. Dashed vertical line indicates the time point of oxytocin or cortex buffer application. Time course represents averages of sliding 7-min window (for details see STAR Methods). The horizontal bar indicates significant deviations from baseline as in Figure 1 (dark shades; paired two-tailed t test; p < 0.05; without multi-measurement correction). Time (min) 25 50 75 50 75 100 Time (min) 25 50 75 100 125 0 Time (min) 0 0.2 0.4 0.6 Pairwise correlation E Cortex buffer Oxt Pairwise correlation ** 0 0.2 0.4 0.6 0.8 0 0.2 0.4 0.6 0.8 Pairwise correlation F Baseline/Cortex buffer Baseline/Oxt E (F) Mean correlations after oxytocin or cortex buffer control applications. **p = 0.003 (n = 7 for oxytocin; n = 6 for cortex buffer; paired two-tailed t test). (G) Pairwise correlations plotted against interneu- ronal distance for an example of oxytocin (left) and cortex buffer (right) conditions. Sensory Areas correlation change Oxt -0.2 0 0.2 0.4 * -0.4 0 100 200 -3 0 3 Normalized correlation Distance (μm) 25 50 75 100 125 0 Time (min) 0 0.2 0.4 0.6 Pairwise correlation E 300 Distance (μm) 0 200 100 1 0.5 0 -0.5 Pairwise correlation H 25 50 75 100 125 0 Time (min) 0 -5 5 10 15 20 Normalized MSD L Cortex buffer Oxt Baseline Oxt Cortex buffer 0.7 Pairwise correlation Baseline Early oxt (60 min) CB 1 0.5 0 -0.5 300 Distance (μm) 0 200 100 Pairwise correlation G Cortex buffer Oxt Cortex buffer Oxt Late oxt (125 min) Baseline Oxt Baseline Cortex buffer Baseline/Cortex buffer Baseline/Oxt Baseline A B 1 2 3 whole field 1 2 3 Oxt B 20 s 10% ΔF/F0 1' 2' 3' 40 μm whole field 1 2 3 Figure 2. Oxytocin Desynchronizes Network Activity in V1 Figure 2. Oxytocin Desynchronizes Network Activity in V1 Left: low magnification is shown. Right: high magnification is shown; note that the Oxtr signal co-localized with both Gad1+ and Gad1 signal (double arrowheads indicate Gad1+/Oxtr+; arrowhead indicates Gad1/Oxtr+ neuron). (H) Q tifi ti proportion of SST+ neurons within the entire population of V1 in- terneurons (23%).35 here that, already at P10, oxytocin receptor mRNA is expressed almost exclusively in SST+ interneurons in layer 2/3 of V1 (Fig- ure 5D). (3) Decreases in network correlations similar to those described above can be induced by SST+ interneuron-mediated lateral inhibition.32,33 (4) We observed here that the rise rate of V1 and S1 sIPSCs increased in response to oxytocin application (Figure S3B). Because the sIPSC rise rate is larger for synapses that are located distally in the dendritic tree, this result indicated that oxytocin preferentially increased the frequency of inhibitory inputs at distal dendrites, which receive the majority of SST+ interneuron inputs.34 here that, already at P10, oxytocin receptor mRNA is expressed almost exclusively in SST+ interneurons in layer 2/3 of V1 (Fig- ure 5D). (3) Decreases in network correlations similar to those described above can be induced by SST+ interneuron-mediated lateral inhibition.32,33 (4) We observed here that the rise rate of V1 and S1 sIPSCs increased in response to oxytocin application (Figure S3B). Because the sIPSC rise rate is larger for synapses that are located distally in the dendritic tree, this result indicated that oxytocin preferentially increased the frequency of inhibitory inputs at distal dendrites, which receive the majority of SST+ interneuron inputs.34 Together, these results indicated that oxytocin mediated the increase in inhibitory synaptic activity in V1 through activation of SST+ interneurons. To test this idea directly, we asked whether specifically downregulating SST+ interneurons might prevent the oxytocin-induced increase in overall inhibition (Fig- ure 5H). We performed voltage-clamp recordings of layer 2/3 neurons in acute slices from V1 of transgenic neonatal mice where SST+ interneurons expressed inhibitory designer recep- tors activated by designer drugs (iDREADDs) (SSTCre;Gi- Dreadd). Bath application of CNO, the activator of iDREADDs, did not affect the baseline frequency of sIPSCs (Figures 5I and 5J), suggesting that SST+ interneurons were only sparsely active in our slice preparation. Figure 2. Oxytocin Desynchronizes Network Activity in V1 0 100 200 -3 0 3 Normalized correlation Distance (μm) H Cortex buffer Oxt Baseline 300 Distance (μm) 0 200 100 1 0.5 0 -0.5 Pairwise correlation Baseline Cortex buffer Time (min) 1 0.5 0 -0.5 300 Distance (μm) 0 200 100 Pairwise correlation G Baseline Oxt Time (min) 300 Distance (μm) 0 200 100 1 0.5 0 -0.5 Pairwise correlation 1 0.5 0 -0.5 300 Distance (μm) 0 200 100 Pairwise correlation G Baseline Oxt Baseline Cortex buffer G H (H) Mean pairwise correlations in oxytocin and cor- tex buffer condition. Note that baseline condition and cortex buffer display the same profile. (I) Change in pairwise correlations plotted against interneuronal distance for an example of oxytocin (left) and cortex buffer (right) conditions. Dashed lines indicate zero change in correlations. Colored lines indicate linear fits (left, p < 1010; right, p = 0.47; paired two-tailed t test). (J) Pearson correlation coefficients between pair- wise distances and percentages of change in cor- relations for all animals in oxytocin and cortex buffer condition. Arrowheads indicate the examples shown in (I). *p = 0.037 (n = 7 for oxytocin; n = 6 for cortex buffer; unpaired two-tailed t test). J Distance vs. correlation change Oxt -0.2 0 0.2 0.4 * -0.4 CB 300 200 100 150 50 % change in correlation Distance (μm) 0 200 100 Corr 0.01 I 300 200 100 150 50 % change in correlation Distance (μm) 0 200 100 Corr -0.32 Oxt Cortex buffer J Distance vs. I J (K) Correlation matrices computed baseline, early oxytocin (60 min), and late oxytocin (125 min). Red dotted square indicates an example of a subgroup of neurons that undergo structural changes. 25 50 75 100 125 0 Time (min) 0 -5 5 10 15 20 Normalized MSD L Cortex buffer Oxt (L) Normalized mean squared distances (MSDs) between the baseline matrix and the correlation matrices computed from a sliding 7-min window (see STAR Methods for details) as function of time for oxytocin and cortex buffer conditions. K 0 0.7 Pairwise correlation Baseline Early oxt (60 min) Late oxt (125 min) L K 1 2 Normalized MSD L Pairwise l ti Data are represented as mean ± SEM. See also Figure S1. Current Biology 31, 322–333, January 25, 2021 325 A B C D E F G H gure 3. Figure 2. Oxytocin Desynchronizes Network Activity in V1 Oxytocin Receptor mRNA Is Differentially Expressed across Sensory Cortices A) Cresyl violet Nissl staining of a sagittal section from V1 at low magnification. Numbers indicate cortical layers. B) Dual-color RNAscope staining of VGLUT1 and Oxtr mRNA in a V1 sagittal section. Left: low magnification is shown. Right: high magnification is shown. Note at the Oxtr signal was largely non-overlapping with the VGLUT1 signal (arrowheads indicate VGLUT1/Oxtr+ neurons). C) Dual-color RNAscope staining of Gad1 and Oxtr mRNA in a V1 sagittal section. Left: low magnification is shown. Right: high magnification is shown; note that e Oxtr signal co-localized with the Gad1 signal (double arrowhead Gad1+/Oxtr+) and not with Gad1 neurons. D) Quantification ll OPEN ACCESS Article Article ll OPEN ACCESS C B D A C D A B E F G E F H H G Figure 3. Oxytocin Receptor mRNA Is Differentially Expressed across Sensory Cortices Figure 3. Oxytocin Receptor mRNA Is Differentially Expressed across Sensory Cortices g y p y p y (A) Cresyl violet Nissl staining of a sagittal section from V1 at low magnification. Numbers indicate cortical layers. (A) Cresyl violet Nissl staining of a sagittal section from V1 at low magnification. Numbers indicate cortical layers. (B) Dual-color RNAscope staining of VGLUT1 and Oxtr mRNA in a V1 sagittal section. Left: low magnification is shown. Right: high magnification is shown. Note that the Oxtr signal was largely non-overlapping with the VGLUT1 signal (arrowheads indicate VGLUT1/Oxtr+ neurons). (C) Dual-color RNAscope staining of Gad1 and Oxtr mRNA in a V1 sagittal section. Left: low magnification is shown. Right: high magnification is shown; note that the Oxtr signal co-localized with the Gad1 signal (double arrowhead Gad1+/Oxtr+) and not with Gad1 neurons. (D) Quantification. (A) Cresyl violet Nissl staining of a sagittal section from V1 at low magnification. Numbers indicate cortical layers. (B) Dual-color RNAscope staining of VGLUT1 and Oxtr mRNA in a V1 sagittal section. Left: low magnification is shown. Right: high magnification is shown. Note that the Oxtr signal was largely non-overlapping with the VGLUT1 signal (arrowheads indicate VGLUT1/Oxtr+ neurons). (C) Dual-color RNAscope staining of Gad1 and Oxtr mRNA in a V1 sagittal section. Left: low magnification is shown. Figure 2. Oxytocin Desynchronizes Network Activity in V1 Right: high magnification is shown; note that the Oxtr signal co-localized with the Gad1 signal (double arrowhead Gad1+/Oxtr+) and not with Gad1 neurons ( ) y g g g y (B) Dual-color RNAscope staining of VGLUT1 and Oxtr mRNA in a V1 sagittal section. Left: low magnification is shown. Righ that the Oxtr signal was largely non-overlapping with the VGLUT1 signal (arrowheads indicate VGLUT1/Oxtr+ neurons). (C) Dual-color RNAscope staining of Gad1 and Oxtr mRNA in a V1 sagittal section. Left: low magnification is shown. Right: hi the Oxtr signal co-localized with the Gad1 signal (double arrowhead Gad1+/Oxtr+) and not with Gad1 neurons. (D) Quantification. that the Oxtr signal was largely non-overlapping with the VGLUT1 signal (arrowheads indicate VGLUT1 /Oxtr neurons). (C) Dual-color RNAscope staining of Gad1 and Oxtr mRNA in a V1 sagittal section. Left: low magnification is shown. Right: high m the Oxtr signal co-localized with the Gad1 signal (double arrowhead Gad1+/Oxtr+) and not with Gad1 neurons. (D) Quantification. color RNAscope staining of Gad1 and Oxtr mRNA in a V1 sagittal section. Left: low magnification is shown. Right: high magnifica signal co-localized with the Gad1 signal (double arrowhead Gad1+/Oxtr+) and not with Gad1 neurons. tification ning of Gad1 and Oxtr mRNA in a V1 sagittal section. Left: low magnification is shown. Right: high magnification is shown; note th ith the Gad1 signal (double arrowhead Gad1+/Oxtr+) and not with Gad1 neurons. (E) Cresyl violet Nissl staining of a sagittal section from S1 (same section as in A) at low magnification. Numbers indicate cortical layers. (F) Dual-color RNAscope staining of VGLUT1 and Oxtr mRNA in an S1 sagittal section. Left: low magnification is shown. Right: high magnification is shown; note the superposition of the two signals (double arrowheads, VGLUT1+/Oxtr+). (G) Dual-color RNAscope staining of Gad1 and Oxtr mRNA in an S1 sagittal section. Left: low magnification is shown. Right: high magnification is shown; note that the Oxtr signal co-localized with both Gad1+ and Gad1 signal (double arrowheads indicate Gad1+/Oxtr+; arrowhead indicates Gad1/Oxtr+ neuron). (H) Q tifi ti (G) Dual-color RNAscope staining of Gad1 and Oxtr mRNA in an S1 sagittal section. Left: low magnification is shown. Right: high magnification is shown; note that the Oxtr signal co-localized with both Gad1+ and Gad1 signal (double arrowheads indicate Gad1+/Oxtr+; arrowhead indicates Gad1/Oxtr+ neuron). (H) Quantification. (G) Dual-color RNAscope staining of Gad1 and Oxtr mRNA in an S1 sagittal section. Figure 2. Oxytocin Desynchronizes Network Activity in V1 Then, we applied oxytocin and found that it did not increase sIPSC frequency in the presence of CNO (Figures 5I and 5J), in contrast to our previous results in sli- ces from wild-type (WT) mice (Figure 4E; fold-change WT: 4.95 ± 1.53; iDREADD: 0.95 ± 0.07; p < 0.0001; Mann-Whitney test). Additional control experiments showed that oxytocin did in- crease the frequency of sIPSCs in neurons from iDREADD-ex- pressing animals in the absence of CNO, but not their amplitude (Figures 5J, inset; S4A; and S4B), and that CNO by itself did not change the sIPSC frequency (Figures S4C and S4D). These Therefore, we investigated the effect of oxytocin on SST+ in- terneurons. We recorded from SST+ neurons in voltage-clamp mode at 60 mV and blocked NMDA, AMPA, and GABAA recep- tor-mediated currents using D-AP5, NBQX, and SR95531, respectively, to prevent oxytocin-mediated network effects. In this configuration, we recorded oxytocin-mediated inward cur- rents in almost all SST+ neurons (83%; amplitude: 27 ± 16 pA; Figures 5E–5G). Oxytocin did not trigger inward currents in any of the SST neurons in slices from the same SST-Cre;R- osa26-TdTomato mice. We concluded that oxytocin triggered depolarizing inward currents specifically in SST+ interneurons. Accordingly, we observed oxytocin induced inward currents in 29% of GAD2+ interneurons (Figure 5G), which is similar to the 326 Current Biology 31, 322–333, January 25, 2021 ll OPEN ACCESS 4 s 400 800 1200 Time (s) 0.2 0.4 0.6 Frequency (Hz) 0 EPSC 25 pA Bl 2 4 6 Frequency (Hz) Oxt 0 Visual cortex Oxt A B 0 results showed that activation of SST+ interneurons is required for the oxytocin-induced increase in inhibition. Figure 4. Oxytocin Affects Synaptic Activity Differentially across Sensory Cortices C Figure 4. Oxytocin Affects Synaptic Activity Differentially across Sensory Cortices B (A) Voltage-clamp recordings of spontaneous excitatory post- synaptic currents (sEPSCs) during baseline (Bl) and after oxytocin bath application in acute visual cortex slices. (B) Frequency of sEPSCs before, during, and after oxytocin application. In the visual cortex, oxytocin did not affect EPSC frequency. p > 0.05 (n = 7 cells; paired two-tailed t test). (C) Oxytocin did not affect sEPSC amplitude. p > 0.05 (n = 7 cells; paired two-tailed t test). **** IPSC Bl 400 800 1200 Time (s) 2 4 6 Frequency (Hz) 50 pA 4 s 2 4 5 1 3 Frequency (Hz) Amplitude (pA) Oxt 0 0 Time (s) 100 0 50 150 0 I 2 4 6 Frequency (fold change) E Oxt D E F G *** 0 0 I 2 4 6 Frequency (fold change) E G *** G (D) Spontaneous inhibitory postsynaptic currents (sIPSCs) before and after oxytocin application. (E) Oxytocin led to a strong increase in sIPSCs. ****p = 8.2 3 105 (n = 8 cells; paired two-tailed t test). (F) Oxytocin did not affect the amplitude of sIPSCs. p > 0.05 (n = 8 cells; paired two-tailed t test). (G) In the visual cortex, oxytocin led to a 5 times increase of sIPSCs, but sEPSCs were unaffected. ***p = 0.0003 (n = 7 and n = 8 cells for V1 sEPSCs and sIPSCs, respectively; Mann-Whitney test). EPSC Bl 25 pA 4 s 1 2 Frequency (Hz) 3 Frequency (Hz) 2 4 6 8 400 800 1200 Time (s) Oxt 0 0 Somatosensory cortex Oxt ** H I 0 I 4 8 12 16 20 Amplitude (pA) 0 Baseline Oxt J J Somatosensory cortex (H) Voltage-clamp recordings of sEPSCs before and after oxytocin bath application in somatosensory cortex slices. (I) Application of oxytocin increased the frequency of sEPSCs in the somatosensory cortex slightly. **p = 0.0014 (n = 7; paired two- tailed t test). (J) Oxytocin did not affect the amplitude of sEPSCs. p > 0.05 (n = 7 cells; paired two-tailed t test). (J) Oxytocin did not affect the amplitude of sEPSCs. p > 0.05 (n = 7 cells; paired two-tailed t test). Figure 4. Oxytocin Affects Synaptic Activity Differentially across Sensory Cortices 20 40 60 Amplitude (pA) 0 0 I 2 4 6 Frequency (fold change) E M N Time (s) 400 800 1200 Time (s) 50 pA 4 s IPSC Bl 2 4 6 Frequency (Hz) 8 2 4 6 Frequency (Hz) Oxt 0 0 Oxt ** K L 0 L M N (K) sIPSCs before and after oxytocin application. (L) Oxytocin led to a transient increase in sIPSCs. **p = 0.002 (n = 8 cells; paired two-tailed t test). (L) Oxytocin led to a transient increase in sIPSCs. **p = 0.002 (n = 8 cells; paired two-tailed t test). (M) Oxytocin did not affect the amplitude of sIPSCs. p > 0.05 (n = 8 cells; paired two-tailed t test). (M) Oxytocin did not affect the amplitude of sIPSCs. p > 0.05 (n = 8 cells; paired two-tailed t test). (N) In the somatosensory cortex, oxytocin led to similar increases in sIPSC and sEPSC frequency. p = 0.11 (n = 7 and n = 8 cells for S1 sEPSCs and sIPSCs, respectively; unpaired two-tailed t test). Data are represented as mean ± SEM. See also Figure S2. results showed that activation of SST+ interneurons is required for the oxytocin-induced increase in inhibition. an AP from the onset of current injection (1.97 ± 0.32 ms; Fig- ure 6F). In addition, oxytocin modulated AP kinetics as it decreased the maximal speed of voltage change (dV/dt; Figures S5B and S5C). Thus, oxytocin increased the firing capacity and AP properties of V1 layer 2/3 SST+ neurons, most likely by depo- larizing their resting membrane potential, as described for PV+ in- terneurons in the hippocampus.36 Knowing how oxytocin affects SST+ interneuron activity, we used this information to better un- derstand how oxytocin generated the observed distance-depen- dent change in correlations. We implemented a recurrent spiking neural network based on a multi-layer model of the thalamocort- ical system (Figure 6G).37 To mimic the effect of oxytocin, we increased the resting membrane potential of 25% of the inhibi- tory neurons, corresponding to the population of SST+ interneu- rons (Figure 6H). This elevation in membrane potential increased the firing rate of SST+ interneurons for identical current injections (Figure 6I) similarly as observed in our data (Figure 6C). Conse- quently, in the simulated network, firing of excitatory neurons was strongly suppressed. Inhibitory neurons fired slightly less as well, because their excitatory inputs were largely diminished (Figure 6J). Figure 4. Oxytocin Affects Synaptic Activity Differentially across Sensory Cortices In addition, oxytocin strongly decreased the temporal synchronization of excitatory neurons (Figures 6K and 6L), generating a comparable decrease of correlations over distance as in our experimental data (Figures 2G–2J). This result sup- ported the idea that the increased inhibitory drive produced by an AP from the onset of current injection (1.97 ± 0.32 ms; Fig- ure 6F). In addition, oxytocin modulated AP kinetics as it decreased the maximal speed of voltage change (dV/dt; Figures S5B and S5C). Thus, oxytocin increased the firing capacity and AP properties of V1 layer 2/3 SST+ neurons, most likely by depo- larizing their resting membrane potential, as described for PV+ in- terneurons in the hippocampus.36 Knowing how oxytocin affects SST+ interneuron activity, we used this information to better un- derstand how oxytocin generated the observed distance-depen- dent change in correlations. We implemented a recurrent spiking neural network based on a multi-layer model of the thalamocort- ical system (Figure 6G).37 To mimic the effect of oxytocin, we increased the resting membrane potential of 25% of the inhibi- tory neurons, corresponding to the population of SST+ interneu- rons (Figure 6H). This elevation in membrane potential increased the firing rate of SST+ interneurons for identical current injections (Figure 6I) similarly as observed in our data (Figure 6C). Conse- quently, in the simulated network, firing of excitatory neurons was strongly suppressed. Inhibitory neurons fired slightly less as well, because their excitatory inputs were largely diminished (Figure 6J). In addition, oxytocin strongly decreased the temporal synchronization of excitatory neurons (Figures 6K and 6L), generating a comparable decrease of correlations over distance as in our experimental data (Figures 2G–2J). This result sup- ported the idea that the increased inhibitory drive produced by Figure 2. Oxytocin Desynchronizes Network Activity in V1 an AP f ure 6F) EPSC Bl 25 pA 4 s 1 2 Frequency (Hz) 3 Frequency (Hz) 2 4 6 8 400 800 1200 Time (s) Oxt 4 8 12 16 20 Amplitude (pA) 0 0 0 400 800 1200 Time (s) 50 pA 4 s IPSC Bl 2 4 6 Frequency (Hz) 8 2 4 6 Frequency (Hz) 20 40 60 Amplitude (pA) Oxt 0 0 0 Somatosensory cortex 0 Oxt Oxt I 2 4 6 Frequency (fold change) E Baseline Oxt ** ** H I J K L M N **** IPSC Bl 400 800 1200 Time (s) 2 4 6 Frequency (Hz) 50 pA 4 s 2 4 5 1 3 Frequency (Hz) Amplitude (pA) Oxt 0 0 4 s 400 800 1200 Time (s) 100 0 50 150 0 I 2 4 6 Frequency (fold change) E Oxt D 0.2 0.4 0.6 Frequency (Hz) 0 EPSC 25 pA Bl Amplitude (pA) 10 20 30 0 2 4 6 Frequency (Hz) Oxt 0 Visual cortex Oxt Baseline Oxt A B E F G C *** 0 0 0 0 Amplitude (pA) 10 20 30 0 Baseline Oxt C Figure 4. Oxytocin Affects Synaptic Activity Differentially across Sensory Cortices Activation of SST+ Interneurons Is Required for Oxytocin-Mediated Modulation of Spontaneous Activity Patterns B A A Finally, we asked whether the oxytocin-mediated decrease in the frequency of spontaneous network activity was the result of the activation of oxytocin receptors expressed in SST+ inter- neurons in vivo. We specifically inactivated SST+ interneurons by using a Cre-dependent inhibitory DREADD delivered by virus injection, which results in 80% of the SST+ interneurons express- ing the hM4Di-DREADD construct.33 We showed previously that bath application of clozapine in vitro reduced the excitability of SST+ interneurons,33 replicating previous findings that hM4Di- DREADD activation reduces the excitability of developing layer 2/3 neurons.38 We performed in vivo wide-field calcium imaging to monitor spontaneous network activity in V1 and then activated the iDREADD receptor by injecting clozapine subcutaneously (Figure 7A). 5 min after clozapine injection, oxytocin was applied topically (Figures 7A and 7B). In this condition, oxytocin failed to decrease the frequency of spontaneous network events compared with oxytocin application alone (Figure 7C, % of change clozapine + oxytocin: 18.1% ± 10.5%; Figure 1D, % of change oxytocin: 49.2% ± 6.2%; p = 0.023; unpaired two- tailed t test). Area, amplitude, and duration were not affected either (Figures 7D–7F). Therefore, SST+ neurons are required for the inhibitory effect of exogenous oxytocin on the frequency of spontaneous activity in the developing visual cortex. E F G F G E F E G E J I I J H J H H Figure 5. SST+ Interneurons Mediate the Oxytocin-Induced Increase in Inhibitory Synaptic Activity in V1 (A) Voltage-clamp recordings of spontaneous miniature synaptic excitatory postsynaptic currents (mIPSCs) in the presence of tetrodotoxin (TTX) (0.5 mM) before and after oxytocin bath application in V1 slices. We demonstrated here that oxytocin receptor activation can modulate spontaneous activity patterns by specifically acti- vating SST+ interneurons; however, the source of oxytocin was exogenous. To evaluate whether endogenous oxytocin indeed modulates spontaneous activity patterns under physiological conditions, we performed wide-field in vivo calcium imaging re- cordings in awake animals, when SST+ interneurons are intrinsi- cally active (SST+ interneurons are largely silent under anes- thesia).32 When we blocked oxytocin receptors, we observed a small but significant increase in the frequency of calcium events (Figure 7G), whereas the amplitude remained unchanged (Fig- ure 7H), as predicted based on our results after topical applica- tion of exogenous oxytocin. This result suggested that the oxytocin receptor is activated by its endogenous ligand and modulates spontaneous activity patterns. Activation of SST+ Interneurons Is Required for Oxytocin-Mediated Modulation of Spontaneous Activity Patterns Finally, we verified that focal oxytocin application modulates spontaneous activity in the awake condition as well. As in anesthetized animals, we found that the frequency of network events was decreased although their amplitude remained unaffected (mean baseline frequency: 0.047 ± 0.007; mean oxytocin frequency: 0.036 ± 0.005; p = 0.043; paired two-tailed t test; n = 6 animals). (B) The frequency of mIPSCs was not affected by oxytocin. p > 0.05 (n = 7 cells; paired two-tailed t test). (C) The amplitude of mIPSCs was not affected by oxytocin. p > 0.05 (n = 7 cells; paired two-tailed t test). (D) V1 Oxtr and Sst mRNA transcripts. Note the superposition of the two sig- nals (arrowhead: Sst+/Oxtr+ neurons: 93%; Sst/Oxtr+ neurons: 2%). (E) Examples of voltage-clamp recordings at holding potential of 60 mV from a somatostatin-expressing neuron (SST+) (SST-Cre;Rosa26-TdTomato), an unlabeled neuron (SST), and a GAD2+ neuron (GAD2+) (GAD2-Cre;Rosa26- TdTomato) before and after oxytocin application. Oxytocin induced an inward current in the SST+ neuron, but not in the unlabeled (most likely excitatory) neuron or in the GAD2+ neuron. (F) Group data of oxytocin-induced inward currents: SST+ n = 17 cells; SST n = 7 cells; and GAD2+ n = 7 cells. *p = 0.021; **p = 0.0044. Kruskal-Wallis test, followed by a Dunn test. (F) Group data of oxytocin-induced inward currents: SST+ n = 17 cells; SST n = 7 cells; and GAD2+ n = 7 cells. *p = 0.021; **p = 0.0044. Kruskal-Wallis test, followed by a Dunn test. (G) Percentage of cells with oxytocin-induced inward currents. Almost all SST+ neurons show oxytocin-mediated currents (14/17 cells) but none of the SST neurons (0/7 cells) and a fraction of GAD2+ cells (2/7 cells). (G) Percentage of cells with oxytocin-induced inward currents. Almost all SST+ neurons show oxytocin-mediated currents (14/17 cells) but none of the SST neurons (0/7 cells) and a fraction of GAD2+ cells (2/7 cells). (H) Schematic representation of the experimental paradigm: pyramidal neu- rons in slices from a transgenic mouse expressing inhibitory DREADDs spe- cifically in SST+ interneurons (SST-Cre;Rosa26-Gi-hMD4i) were recorded in voltage-clamp mode. Oxytocin was applied while SST+ neuron activity was suppressed by CNO to test whether SST+ activation is required for the oxytocin-induced increase in inhibitory synaptic activity. Oxytocin Enhances SST+ Neuron Excitability Our results suggested that oxytocin triggered inward currents in SST+ interneurons (Figures 5E–5G) and that oxytocin-dependent enhancement of SST+ interneuron firing mediated its effect on network activity (Figures 5H–5J). Therefore, we investigated next whether and how oxytocin-induced inward currents enhanced SST+ neuron firing. In current-clamp mode, we in- jected a constant current to set the membrane potential of V1 layer 2/3 SST+ interneurons to 60 mV in the presence of the transmitter receptor blockers D-AP5, NBQX, and SR95531. Then, we applied oxytocin while keeping the holding current con- stant. We observed that oxytocin induced a depolarization of 4.5 ± 0.4 mV (Figure 6A), which exhibited the same transient tem- poral profile as the sIPSC frequency increase shown in Figure 4E. Current-clamp recordings (Figure 6B) revealed an increase in the firing rate of SST+ interneurons after oxytocin application (Fig- ure 6C). We further studied how oxytocin affected the action po- tential (AP) properties of SST+ interneurons. Oxytocin (1) increased the AP amplitude and overshoot (Figures 6D and S5A; +2.63 ± 0.78 mV and +2.01 ± 0.93 mV, respectively), (2) broadened the AP width (+0.18 ± 0.03 ms at half-maximum; Fig- ures 6D and 6E), and (3) decreased the time required to generate Current Biology 31, 322–333, January 25, 2021 327 Article E F G H C B A I D J Figure 5. SST+ Interneurons Mediate the Oxytocin-Induced Increase in Inhibitory Synaptic Activity in V1 C B A D Activation of SST+ Interneurons Is Required for Oxytocin-Mediated Modulation of Spontaneous Activity Patterns DISCUSSION Right: group data of SST+ interneuron membrane potential in baseline and oxytocin conditions are shown. ****p = 4.7 3 1010 (n = 34 cells; paired two- tailed t test). D E F E F D (B) Train of APs generated with a ramp protocol in current-clamp mode in baseline and oxytocin condi- tions. (C) Instantaneous frequency versus current plot. ***p < 0.0001 (n = 34 cells; repeated-measurements two- way ANOVA). (D) Left: single APs aligned to the peak in baseline and oxytocin conditions. Right: group data of AP amplitude in baseline and oxytocin conditions are shown. *p = 0.038 (n = 34 cells; paired two-tailed t test). I H G H I H G (E) AP width. ****p = 1.8 3 106 (paired two-tailed t test). (F) AP. Left: single APs in response to a square current step in baseline and oxytocin conditions. The time required to elicit an action potential was strongly reduced in the presence of oxytocin. ****p = 8.9 3 107 (paired two-tailed t test). Data are represented as mean ± SEM. K L L J K J J K (G) Left: schematic of the model with excitatory background input and recurrently connected excit- atory (red) and inhibitory populations (blue). We, excitatory weight; Wi, inhibitory weight. Right: connection probability as a function of distance be- tween cells is shown. (H) Resting membrane potential of SST+ interneurons during baseline and oxytocin. (I) Firing rate of inhibitory cells as a function of the input current in baseline and oxytocin. (I) Firing rate of inhibitory cells as a function of the input current in baseline and oxytocin. (J) Spike raster plot of excitatory (red) and SST+ interneurons (blue) neuron populations before and after application of oxytocin (see STAR Methods). (K) Correlation as a function of distance for baseline and oxytocin conditions. See STAR Methods for calculation details. (L) Change in correlation as a function of distance. See also Figure S5 and Table S1. (I) Firing rate of inhibitory cells as a function of the input current in baseline and oxytocin. (J) Spike raster plot of excitatory (red) and SST+ interneurons (blue) neuron populations before and after application of oxytocin (see STAR Methods) (K) Correlation as a function of distance for baseline and oxytocin conditions. See STAR Methods for calculation details. (L) Change in correlation as a function of distance. See also Figure S5 and Table S1. The Effect of Oxytocin Receptor Activation Differs between V1 and S1 endogenous ligand and modulates spontaneous activity pat- terns during development. DISCUSSION (I) Example recordings of sIPSCs in baseline condition, in the presence of CNO alone, and after bath application of oxytocin in the presence of CNO. (I) Example recordings of sIPSCs in baseline condition, in the presence of CNO alone, and after bath application of oxytocin in the presence of CNO. (J) Oxytocin did not increase sIPSC frequency in the presence of CNO. p > 0.05 (n = 12 cells; repeated-measurements one-way ANOVA). Inset: sIPSC fre- quency is shown. Oxytocin led to an increase in the frequency in the absence of CNO. *p = 0.032 (n = 3 cells; paired two-tailed t test). In adults, oxytocin is a potent modulator of brain activity and behavior, and it is important for brain development. Here, we demonstrate that, before eye opening, during the 2nd postnatal week, oxytocin modulates specific characteristics of sponta- neous activity patterns in the visual cortex: it selectively in- creases SST+ interneuron excitability through oxytocin receptor activation and sparsifies and decorrelates neuronal activity in layer 2/3 of V1 without affecting event area, amplitude, or duration. In adults, oxytocin is a potent modulator of brain activity and behavior, and it is important for brain development. Here, we demonstrate that, before eye opening, during the 2nd postnatal week, oxytocin modulates specific characteristics of sponta- neous activity patterns in the visual cortex: it selectively in- creases SST+ interneuron excitability through oxytocin receptor activation and sparsifies and decorrelates neuronal activity in layer 2/3 of V1 without affecting event area, amplitude, or duration. ta are represented as mean ± SEM. See also Figures S3 and S4 Data are represented as mean ± SEM. See also Figures S3 and S4. oxytocin is sufficient to generate the here-observed effects of oxytocin applications on spontaneous activity patterns, including the distance-dependent changes in interneuronal correlations. 328 Current Biology 31, 322–333, January 25, 2021 Article ll OPEN ACCESS A B C D E F G H I L K J Figure 6. Oxytocin-Induced Increase o Excitability of SST+ Interneurons Is Suffi to Explain Distance-Dependent Chang Correlation (A) Average of current-clamp recordings of neurons before and after oxytocin bath appli Right: group data of SST+ interneuron mem potential in baseline and oxytocin conditio shown. ****p = 4.7 3 1010 (n = 34 cells; paire tailed t test). (B) Train of APs generated with a ramp prot current-clamp mode in baseline and oxytocin tions. between V1 and S1 Independently of the source of oxytocin, we find here that this neuropeptide strongly decreases spontaneous network activity in V1, although its effect on spontaneous network activity in S1 is comparably mild. The differences between oxytocin’s effect on V1 and S1 network activity are consistent with differences in the expression of its receptor across cell types and their spe- cific responses to oxytocin. Oxytocin receptor mRNA expression co-localizes with the interneuron marker GAD1 in both V1 and S1; however, its expression in excitatory neurons is higher in S1 than V1. Furthermore, oxytocin increases specifically inhibi- tory synaptic transmission in V1, but in S1, it results in a smaller and more-balanced activation of both spontaneous inhibitory and excitatory currents. Thus, the specific effect of oxytocin on inhibitory signaling is most likely responsible for its effect on network activity patterns in V1. In the adult, various brain regions differ in their responses to oxytocin due to differences in the dis- tribution of the oxytocin receptor in inhibitory neurons as well;17,18,36,44–47 however, whether oxytocin signaling differs be- tween V1 and S1 in adulthood too is currently unknown. A large body of evidence suggests that maternal care behaviors induce activation of hypothalamic neurons and release of oxytocin in the pup’s brain (e.g., during mother-pup skin-to- skin contact,39 anogenital stimulation,40 or stroking stimuli,41 and most likely after milk suckling activity42). Accordingly, so- matosensory stimuli specifically activate parvocellular oxytocin neurons in the paraventricular nucleus (PVN).43 How oxytocin reaches the developing cortex is not entirely clear. It might be released within V1, because hypothalamic oxytocin neurons project to the cortex, including V1, at least in adult mice.17,44 Alternatively, oxytocin may diffuse into the developing cortex af- ter somatodendritic release from the hypothalamus into the third ventricle.15,28,42 To fully disentangle how oxytocin reaches the developing cortex and to induce endogenous release, it will be required to adapt technical approaches currently available in adults18,36,44 to neonatal animals. Nevertheless, our observation that blocking cortical oxytocin receptors increases the fre- quency of spontaneous network activity in V1 of awake animals indicates that the oxytocin receptor is activated by its A large body of evidence suggests that maternal care behaviors induce activation of hypothalamic neurons and release of oxytocin in the pup’s brain (e.g., during mother-pup skin-to- skin contact,39 anogenital stimulation,40 or stroking stimuli,41 and most likely after milk suckling activity42). DISCUSSION (C) Instantaneous frequency versus current plot 0.0001 (n = 34 cells; repeated-measurement way ANOVA). (D) Left: single APs aligned to the peak in ba and oxytocin conditions. Right: group data amplitude in baseline and oxytocin conditio shown. *p = 0.038 (n = 34 cells; paired two-t test). (E) AP width. ****p = 1.8 3 106 (paired two- test). (F) AP. Left: single APs in response to a square step in baseline and oxytocin conditions. Th required to elicit an action potential was s reduced in the presence of oxytocin. ****p = 107 (paired two-tailed t test). Data are represen mean ± SEM. (G) Left: schematic of the model with exc background input and recurrently connected atory (red) and inhibitory populations (blue excitatory weight; Wi, inhibitory weight. connection probability as a function of distan tween cells is shown. (H) Resting membrane potential of SST+ intern during baseline and oxytocin. (I) Firing rate of inhibitory cells as a function of the input current in baseline and oxytocin. (J) Spike raster plot of excitatory (red) and SST+ interneurons (blue) neuron populations before and after application of oxytocin (see STAR Methods). (K) Correlation as a function of distance for baseline and oxytocin conditions. See STAR Methods for calculation details. (L) Change in correlation as a function of distance. See also Figure S5 and Table S1. A B C D E F G H I L K J (I) Firing rate of inhibitory cells as a function of the input current in baseline and oxytocin. (J) Spike raster plot of excitatory (red) and SST+ interneurons (blue) neuron populations before and after ap (K) Correlation as a function of distance for baseline and oxytocin conditions. See STAR Methods for calcu (L) Change in correlation as a function of distance. See also Figure S5 and Table S1. B A C Figure 6. Oxytocin-Induced Increase of the Excitability of SST+ Interneurons Is Sufficient to Explain Distance-Dependent Changes in Correlation Figure 6. Oxytocin-Induced Increase of the Excitability of SST+ Interneurons Is Sufficient to Explain Distance-Dependent Changes in Correlation C B A (A) Average of current-clamp recordings of SST+ neurons before and after oxytocin bath application. (A) Average of current-clamp recordings of SST+ neurons before and after oxytocin bath application. Right: group data of SST+ interneuron membrane potential in baseline and oxytocin conditions are shown. ****p = 4.7 3 1010 (n = 34 cells; paired two- tailed t test). Oxytocin Desynchronizes the Network in a Structured Manner 0 We observed that oxytocin decreases pairwise cor- relations between neurons. This decorrelation is mediated most likely by oxytocin-induced activation of SST+ interneurons, in agreement with previously published findings: activation of interneurons decreases neuronal corre- lations in general.53,54 More specifically, lateral inhibition, a role attributed to SST+ interneurons, decorrelates spike trains55 or stimulus-evoked patterns,56 and pharmacogenetic inactivation of SST+ interneurons increases pairwise correla- tions during spontaneous network activity in the developing vi- sual cortex.33 Our analyses and simulations suggest that cor- relations are downregulated in a spatially specific manner: correlation decreases are more pronounced between pairs of neurons that are farther apart. Neuronal correlations and the spatial extent of spontaneous network activity patterns determine their effectiveness in refining synaptic connections in the visual system.11,25,57,58 Therefore, the regulation of spatial correlations through oxytocin may be necessary to shape spontaneous activity patterns to drive the refinement of synaptic connections and to prepare the emerging network optimally for computing visual inputs after eye opening. It might be tempting to speculate that oxytocin contributes to improved visual acuity after tactile stimulation during development.59 SST+ Interneuron Activation Accounts for the Oxytocin- Mediated Increase in V1 Inhibitory Transmission We propose here that the specific activation of SST+ interneu- rons through oxytocin modulates spontaneous activity patterns in the developing V1 based on five observations: (1) the oxytocin receptor is transcribed in V1 SST+ interneurons but barely de- tected in other interneuron types, excitatory neurons, or glia cells.31 (2) Pharmacogenetic suppression of SST+ neurons pre- vents the oxytocin-mediated decrease in network event fre- quency in vivo. (3) Oxytocin induces an inward current in almost all SST+ interneurons and in a fraction of GAD2+ interneurons. (4) Oxytocin-mediated depolarization of SST+ interneurons in- creases the frequency of inhibitory synaptic inputs in pyramidal cells 5-fold, and (5) this increase is abolished entirely by SST+ interneuron inactivation. Our finding that oxytocin increases inhibitory function through SST+ interneuron activation and decreases spontaneous activity during an important step in visual cortex development supports the idea that oxytocin modulation of inhibition facilitates the developmental progression across critical periods.19,48 During development, changes in the E/I balance are important, because they determine the opening or closure of critical periods, during which sensory pathways become sensitive to experience.49 Furthermore, the maturation of inhibition may be required for decreasing spontaneous activity,50 thereby increasing the rela- tive importance of visually evoked activity. Figure 7. Role for SST+ Interneurons and Endogenous Oxytocin Receptor Activation in Modulating Network Ac- tivity In Vivo B A (A) Schematic representation of the experimental design: wide- field calcium imaging of spontaneous network activity in SST-Cre mice where V1 neurons express GCaMP6s and GiDreadd after viral transduction. Baseline Cloz + Oxt 0 1 2 3 Time (min) 20 40 60 80 ClozapineOxt 2 Area (mm ) D 0 1 2 3 2 Area (mm ) 50 s 0 2 0 2 6 4 8 Frequency (Hz) Frequency (Hz) ClozapineOxt -2 x10 -2 x10 C Time (min) 6 0 20 40 60 80 4 0 D C (B) Fluorescent changes before and after clozapine + oxytocin application. (C) Network event frequency during baseline and after oxytocin application. Time courses represent 5-min averages. Dashed light blue curve represents data shown in Figure 1D, V1, for comparison. (D) Network event area. (D) Network event area. (E) Network event amplitude. (F) Network event duration. Data are represented as mean ± SEM. (G) Network event frequency during baseline and after oxytocin receptor antagonist application, in awake animals. *p = 0.037 (n = 7 animals; paired two-tailed t test). Data are represented as mean ± SEM. ( ) ClozapineOxt Time (min) 20 40 60 80 0 1 2 3 4 5 Duration (s) 0 1 2 3 4 Duration (s) F 0 0 40 80 120 Amplitude (ΔF/F ) 0 ClozapineOxt Time (min) 20 40 60 80 0 40 80 120 Amplitude (ΔF/F ) 0 E ( ) 0 F 5 F E (H) Network event amplitude during baseline and after oxytocin receptor antagonist application, in awake animals. 2 0 4 6 8 Frequency (Hz) * OxtR ant Normalized frequency 0 1 1.1 1.2 0 20 40 60 80 Time (min) 0.9 G x10-2 Baseline OxtR antagonist 0 50 100 Amplitude (%ΔF/F ) 0 75 25 OxtR ant 0 20 40 60 80 Time (min) Normalized amplitude 0 1 1.2 0.8 H G H Baseline OxtR antagonist 2 weeks after eye opening.51 Thus, oxytocin may be an important regulator of ‘‘phenotypic checkpoints’’ important for sensitive periods during postnatal development.52 between V1 and S1 Our finding that oxytocin increases inhibitory function through SST+ interneuron activation and decreases spontaneous activity during an important step in visual cortex development supports the idea that oxytocin modulation of inhibition facilitates the developmental progression across critical periods.19,48 During development, changes in the E/I balance are important, because they determine the opening or closure of critical periods, during which sensory pathways become sensitive to experience.49 Furthermore, the maturation of inhibition may be required for decreasing spontaneous activity,50 thereby increasing the rela- tive importance of visually evoked activity. This relative increase in experience-driven activity could initiate the critical period 2 0 2 6 4 8 Frequency (Hz) Frequency (Hz) ClozapineOxt -2 x10 -2 x10 0 40 80 120 Amplitude (ΔF/F ) 0 ClozapineOxt Time (min) 20 40 60 80 0 40 80 120 Amplitude (ΔF/F ) 0 C E Time (min) 6 0 20 40 60 80 4 Baseline Cloz + Oxt 0 1 2 3 Time (min) 20 40 60 80 ClozapineOxt 2 Area (mm ) ClozapineOxt Time (min) 20 40 60 80 0 1 2 3 4 5 Duration (s) 0 1 2 3 4 Duration (s) D F 0 1 2 3 2 Area (mm ) A B 50 s Baseline Clozapine + Oxt 50% ΔF/F0 SSTCre mice GiDreadd virus Oxt Clozapine 0 0 0 0 2 0 4 6 8 Frequency (Hz) Baseline OxtR antagonist 0 50 100 Amplitude (%ΔF/F ) 0 75 25 * OxtR ant OxtR ant 0 20 40 60 80 Time (min) Normalized amplitude 0 1 1.2 0.8 Normalized frequency 0 1 1.1 1.2 0 20 40 60 80 Time (min) 0.9 G H x10-2 F O t (A fi m v (B a (C a li c (D (E (F (G r 7 m (H r 2 a im d O S W r m of SST+ int findings: ac lations in g role attrib trains55 or inactivation tions during sual cortex relations a correlation of neurons the spatial determine in the visu spatial cor shape spo of synaptic optimally f might be t improved developme During th from high-c sparser an patterns ha Because ox week and A SSTCre mice GiDreadd virus Oxt Clozapine B 50 s Baseline Clozapine + Oxt 50% ΔF/F0 330 Current Biology 31, 322–333, January 25, 2021 between V1 and S1 Accordingly, so- matosensory stimuli specifically activate parvocellular oxytocin neurons in the paraventricular nucleus (PVN).43 How oxytocin reaches the developing cortex is not entirely clear. It might be released within V1, because hypothalamic oxytocin neurons project to the cortex, including V1, at least in adult mice.17,44 Current Biology 31, 322–333, January 25, 2021 329 Article ll OPEN ACCESS SST+ Interneuron Activation Accounts for the Oxytocin- Mediated Increase in V1 Inhibitory Transmission 2 0 2 6 4 8 Frequency (Hz) Frequency (Hz) ClozapineOxt -2 x10 -2 x10 0 40 80 120 Amplitude (ΔF/F ) 0 ClozapineOxt Time (min) 20 40 60 80 0 40 80 120 Amplitude (ΔF/F ) 0 C E Time (min) 6 0 20 40 60 80 4 Baseline Cloz + Oxt 0 1 2 3 Time (min) 20 40 60 80 ClozapineOxt 2 Area (mm ) ClozapineOxt Time (min) 20 40 60 80 0 1 2 3 4 5 Duration (s) 0 1 2 3 4 Duration (s) D F 0 1 2 3 2 Area (mm ) A B 50 s Baseline Clozapine + Oxt 50% ΔF/F0 SSTCre mice GiDreadd virus Oxt Clozapine 0 0 0 0 2 0 4 6 8 Frequency (Hz) Baseline OxtR antagonist 0 50 100 Amplitude (%ΔF/F ) 0 75 25 * OxtR ant OxtR ant 0 20 40 60 80 Time (min) Normalized amplitude 0 1 1.2 0.8 Normalized frequency 0 1 1.1 1.2 0 20 40 60 80 Time (min) 0.9 G H x10-2 of SST+ findings: SST+ Interneuron Activation Accounts for the Oxytocin- Mediated Increase in V1 Inhibitory Transmission We propose here that the specific activation of SST+ interneu- rons through oxytocin modulates spontaneous activity patterns in the developing V1 based on five observations: (1) the oxytocin receptor is transcribed in V1 SST+ interneurons but barely de- tected in other interneuron types, excitatory neurons, or glia cells.31 (2) Pharmacogenetic suppression of SST+ neurons pre- vents the oxytocin-mediated decrease in network event fre- quency in vivo. (3) Oxytocin induces an inward current in almost all SST+ interneurons and in a fraction of GAD2+ interneurons. (4) Oxytocin-mediated depolarization of SST+ interneurons in- creases the frequency of inhibitory synaptic inputs in pyramidal cells 5-fold, and (5) this increase is abolished entirely by SST+ interneuron inactivation. Oxytocin Desynchronizes the Network in a Structured Manner This relative increase in experience-driven activity could initiate the critical period During the 2nd postnatal week, V1 activity patterns change from high-correlation, high-cell-participation patterns toward sparser and less-correlated activity. Sparsification of activity patterns has been shown to be largely pre-programmed.60–62 Because oxytocin signaling ramps up during the 2nd postnatal week and sparsifies activity patterns as discussed above, During the 2nd postnatal week, V1 activity patterns change from high-correlation, high-cell-participation patterns toward sparser and less-correlated activity. Sparsification of activity patterns has been shown to be largely pre-programmed.60–62 d Because oxytocin signaling ramps up during the 2nd postnatal week and sparsifies activity patterns as discussed above, 330 Current Biology 31, 322–333, January 25, 2021 Article ll OPEN ACCESS ll OPEN ACCESS AUTHOR CONTRIBUTIONS oxytocin and potentially other neuromodulators may drive the sparsification and decorrelation seen in spontaneous activity patterns toward the onset of sensation. In this regard, it is interesting to note that activity patterns in the Fmr1 knockout (KO) mouse, a model for the neurodevelopmental disorder fragile X syndrome, show increased correlations in the devel- oping somatosensory and visual cortices compared to WT lit- termates.63,64 In addition, atypical oxytocin signaling has been implicated as a risk factor for neurodevelopmental disor- ders.65–67 Thus, oxytocin may be important for healthy brain development to specifically shape activity patterns for synap- tic refinement by regulating SST+ interneuron function. Conceptualization, P.P.M. and C.L.; Experiments, P.P.M., A.N.-P., and E.H.; Analysis, P.P.M., A.N.-P., J.K., and J.G.; Writing, P.P.M. and C.L. d KEY RESOURCES TABLE 3. Kirkby, L.A., Sack, G.S., Firl, A., and Feller, M.B. (2013). A role for corre- lated spontaneous activity in the assembly of neural circuits. Neuron 80, 1129–1144. d KEY RESOURCES TABLE d RESOURCE AVAILABILITY B Lead Contact B Materials Availability B Data and Code Availability d EXPERIMENTAL MODEL AND SUBJECT DETAILS B Animal d METHOD DETAILS B In utero electroporation and surgery B Virus injection B Wide-field imaging B 2-photon imaging B Patch-clamp experiments B RNAscope B Model d QUANTIFICATION AND STATISTICAL ANALYSIS B 2-photon imaging analysis B Wide-field imaging analysis B Electrophysiological analysis B RNAscope analysis B Statistics d RESOURCE AVAILABILITY B Lead Contact B Materials Availability 4. Meister, M., Wong, R.O.L., Baylor, D.A., and Shatz, C.J. (1991). Synchronous bursts of action potentials in ganglion cells of the developing mammalian retina. Science 252, 939–943. B Data and Code Availability d EXPERIMENTAL MODEL AND SUBJECT DETAILS B Animal 5. Feller, M.B., Wellis, D.P., Stellwagen, D., Werblin, F.S., and Shatz, C.J. (1996). Requirement for cholinergic synaptic transmission in the propaga- tion of spontaneous retinal waves. Science 272, 1182–1187. 6. Ackman, J.B., Burbridge, T.J., and Crair, M.C. (2012). Retinal waves coor- dinate patterned activity throughout the developing visual system. Nature 490, 219–225. 7. Siegel, F., Heimel, J.A., Peters, J., and Lohmann, C. (2012). Peripheral and central inputs shape network dynamics in the developing visual cortex in vivo. Curr. Biol. 22, 253–258. 8. Colonnese, M.T., Shen, J., and Murata, Y. (2017). Uncorrelated neural firing in mouse visual cortex during spontaneous retinal waves. Front. Cell. Neurosci. 11, 289. 9. Weliky, M., and Katz, L.C. (1997). Disruption of orientation tuning in visual cortex by artificially correlated neuronal activity. Nature 386, 680–685. B Electrophysiological analysis 10. Cang, J., Renterı´a, R.C., Kaneko, M., Liu, X., Copenhagen, D.R., and Stryker, M.P. (2005). Development of precise maps in visual cortex re- quires patterned spontaneous activity in the retina. Neuron 48, 797–809. B RNAscope analysis B Statistics 11. Burbridge, T.J., Xu, H.-P., Ackman, J.B., Ge, X., Zhang, Y., Ye, M.-J., Zhou, Z.J., Xu, J., Contractor, A., and Crair, M.C. (2014). Visual circuit development requires patterned activity mediated by retinal acetylcholine receptors. Neuron 84, 1049–1064. The authors declare no competing interests. The authors declare no competing interests. Received: February 7, 2020 Revised: August 28, 2020 Accepted: October 9, 2020 Published: November 5, 2020 SUPPLEMENTAL INFORMATION Supplemental Information can be found online at https://doi.org/10.1016/j. cub.2020.10.028. 12. Tyzio, R., Nardou, R., Ferrari, D.C., Tsintsadze, T., Shahrokhi, A., Eftekhari, S., Khalilov, I., Tsintsadze, V., Brouchoud, C., Chazal, G., et al. (2014). Oxytocin-mediated GABA inhibition during delivery attenuates autism pathogenesis in rodent offspring. Science 343, 675–679. STAR+METHODS 1. Katz, L.C., and Shatz, C.J. (1996). Synaptic activity and the construction of cortical circuits. Science 274, 1133–1138. Detailed methods are provided in the online version of this paper and include the following: 2. Sanes, J.R., and Yamagata, M. (2009). Many paths to synaptic specificity. Annu. Rev. Cell Dev. Biol. 25, 161–195. d KEY RESOURCES TABLE ACKNOWLEDGMENTS Interplay between oxytocin and sen- sory systems in the orchestration of socio-emotional behaviors. Neuron 99, 887–904. 39. Kojima, S., Stewart, R.A., Demas, G.E., and Alberts, J.R. (2012). Maternal contact differentially modulates central and peripheral oxytocin in rat pups during a brief regime of mother-pup interaction that induces a filial hud- dling preference. J. Neuroendocrinol. 24, 831–840. 20. Burkett, J.P., Andari, E., Johnson, Z.V., Curry, D.C., de Waal, F.B.M., and Young, L.J. (2016). Oxytocin-dependent consolation behavior in rodents. Science 351, 375–378. 40. Caba, M., Rovirosa, M.J., and Silver, R. (2003). Suckling and genital strok- ing induces Fos expression in hypothalamic oxytocinergic neurons of rab- bit pups. Brain Res. Dev. Brain Res. 143, 119–128. 21. Ferretti, V., Maltese, F., Contarini, G., Nigro, M., Bonavia, A., Huang, H., Gigliucci, V., Morelli, G., Scheggia, D., Manago` , F., et al. (2019). Oxytocin signaling in the central amygdala modulates emotion discrimina- tion in mice. Curr. Biol. 29, 1938–1953.e6. 41. Okabe, S., Yoshida, M., Takayanagi, Y., and Onaka, T. (2015). Activation of hypothalamic oxytocin neurons following tactile stimuli in rats. Neurosci. Lett. 600, 22–27. 22. Tyzio, R., Cossart, R., Khalilov, I., Minlebaev, M., Hu¨ bner, C.A., Represa, A., Ben-Ari, Y., and Khazipov, R. (2006). Maternal oxytocin triggers a tran- sient inhibitory switch in GABA signaling in the fetal brain during delivery. Science 314, 1788–1792. 42. Grinevich, V., Desarmenien, M.G., Chini, B., Tauber, M., and Muscatelli, F. (2015). Ontogenesis of oxytocin pathways in the mammalian brain: late maturation and psychosocial disorders. Front. Neuroanat. 8, 164. 43. Tang, Y., Benusiglio, D., Lefevre, A., Hilfiger, L., Althammer, F., Bludau, A., Hagiwara, D., Baudon, A., Darbon, P., Schimmer, J., et al. (2020). Social touch promotes interfemale communication via activation of parvocellular oxytocin neurons. Nat. Neurosci. 23, 1125–1137. 23. Winnubst, J., Cheyne, J.E., Niculescu, D., and Lohmann, C. (2015). Spontaneous activity drives local synaptic plasticity in vivo. Neuron 87, 399–410. 24. Stosiek, C., Garaschuk, O., Holthoff, K., and Konnerth, A. (2003). In vivo two-photon calcium imaging of neuronal networks. Proc. Natl. Acad. Sci. USA 100, 7319–7324. 44. Knobloch, H.S., Charlet, A., Hoffmann, L.C., Eliava, M., Khrulev, S., Cetin, A.H., Osten, P., Schwarz, M.K., Seeburg, P.H., Stoop, R., and Grinevich, V. (2012). Evoked axonal oxytocin release in the central amygdala attenu- ates fear response. Neuron 73, 553–566. 25. Leighton, A.H., and Lohmann, C. (2016). The wiring of developing sensory circuits-from patterned spontaneous activity to synaptic plasticity mecha- nisms. Front. ACKNOWLEDGMENTS We thank Corette Wierenga, Nicole Ropert, and Marcus Howlett for critically reading the manuscript; Gertjan Houwen for his help with MATLAB coding; Maurice Manning for the donation of the oxytocin receptor antagonist; Moni- que van Mourik for performing the in utero electroporations and virus injection; Fred de Winter for the production of AAV-hSyn-DIO-hM4D(Gi)-mCherry virus; and Marko Popovic for sharing with us the Rapid LED Switching System for one-photon microscopy. We thank the Helmut Kessels lab for sharing equip- ment, The Allen Brain Institute for permission to reproduce their data in Fig- ure S3, and Marian Verhage for helping with our mice colony. This work was supported by grants of the Netherlands Organization for Scientific Research (NWO, ALW Open Program grants nos. 819.02.017, 822.02.006, and AL- WOP.216; ALW Vici, no. 865.12.001), the ‘‘Stichting Vrienden van het Herse- ninstituut’’ (all C.L.), and the Max Planck Society and European Research Council StG 804824 (J.G.). 13. Hanganu, I.L., Staiger, J.F., Ben-Ari, Y., and Khazipov, R. (2007). Cholinergic modulation of spindle bursts in the neonatal rat visual cortex in vivo. J. Neurosci. 27, 5694–5705. 14. Sarro, E.C., Wilson, D.A., and Sullivan, R.M. (2014). Maternal regulation of infant brain state. Curr. Biol. 24, 1664–1669. 15. Zheng, J.-J., Li, S.-J., Zhang, X.-D., Miao, W.-Y., Zhang, D., Yao, H., and Yu, X. (2014). Oxytocin mediates early experience-dependent cross- modal plasticity in the sensory cortices. Nat. Neurosci. 17, 391–399. 16. Hammock, E.A., and Levitt, P. (2013). Oxytocin receptor ligand binding in embryonic tissue and postnatal brain development of the C57BL/6J mouse. Front. Behav. Neurosci. 7, 195. 17. Mitre, M., Marlin, B.J., Schiavo, J.K., Morina, E., Norden, S.E., Hackett, T.A., Aoki, C.J., Chao, M.V., and Froemke, R.C. (2016). A distributed Current Biology 31, 322–333, January 25, 2021 331 Article ll OPEN ACCESS network for social cognition enriched for oxytocin receptors. J. Neurosci. 36, 2517–2535. 37. Hill, S., and Tononi, G. (2005). Modeling sleep and wakefulness in the tha- lamocortical system. J. Neurophysiol. 93, 1671–1698. 18. Marlin, B.J., Mitre, M., D’amour, J.A., Chao, M.V., and Froemke, R.C. (2015). Oxytocin enables maternal behaviour by balancing cortical inhibi- tion. Nature 520, 499–504. 38. Naskar, S., Narducci, R., Balzani, E., Cwetsch, A.W., Tucci, V., and Cancedda, L. (2019). The development of synaptic transmission is time- locked to early social behaviors in rats. Nat. Commun. 10, 1195. 19. Grinevich, V., and Stoop, R. (2018). ACKNOWLEDGMENTS Neural Circuits 10, 71. 45. Mu¨ hlethaler, M., Charpak, S., and Dreifuss, J.J. (1984). Contrasting effects of neurohypophysial peptides on pyramidal and non-pyramidal neurones in the rat hippocampus. Brain Res. 308, 97–107. 26. Cossell, L., Iacaruso, M.F., Muir, D.R., Houlton, R., Sader, E.N., Ko, H., Hofer, S.B., and Mrsic-Flogel, T.D. (2015). Functional organization of excit- atory synaptic strength in primary visual cortex. Nature 518, 399–403. 46. Owen, S.F., Tuncdemir, S.N., Bader, P.L., Tirko, N.N., Fishell, G., and Tsien, R.W. (2013). Oxytocin enhances hippocampal spike transmission by modulating fast-spiking interneurons. Nature 500, 458–462. 27. Ko, H., Cossell, L., Baragli, C., Antolik, J., Clopath, C., Hofer, S.B., and Mrsic-Flogel, T.D. (2013). The emergence of functional microcircuits in vi- sual cortex. Nature 496, 96–100. 47. Nakajima, M., Go¨ rlich, A., and Heintz, N. (2014). Oxytocin modulates fe- male sociosexual behavior through a specific class of prefrontal cortical interneurons. Cell 159, 295–305. 28. Chini, B., Verhage, M., and Grinevich, V. (2017). The action radius of oxytocin release in the mammalian CNS: from single vesicles to behavior. Trends Pharmacol. Sci. 38, 982–991. 48. Hammock, E.A.D. (2015). Developmental perspectives on oxytocin and vasopressin. Neuropsychopharmacology 40, 24–42. 29. Schorscher-Petcu, A., Sotocinal, S., Ciura, S., Dupre, A., Ritchie, J., Sorge, R.E., Crawley, J.N., Hu, S.-B., Nishimori, K., Young, L.J., et al. (2010). Oxytocin-induced analgesia and scratching are mediated by the vasopressin-1A receptor in the mouse. J. Neurosci. 30, 8274–8284. 49. Hensch, T.K. (2005). Critical period plasticity in local cortical circuits. Nat. Rev. Neurosci. 6, 877–888. 50. Colonnese, M.T. (2014). Rapid developmental emergence of stable depo- larization during wakefulness by inhibitory balancing of cortical network excitability. J. Neurosci. 34, 5477–5485. 30. Manning, M., Misicka, A., Olma, A., Bankowski, K., Stoev, S., Chini, B., Durroux, T., Mouillac, B., Corbani, M., and Guillon, G. (2012). Oxytocin and vasopressin agonists and antagonists as research tools and potential therapeutics. J. Neuroendocrinol. 24, 609–628. 51. Toyoizumi, T., Miyamoto, H., Yazaki-Sugiyama, Y., Atapour, N., Hensch, T.K., and Miller, K.D. (2013). A theory of the transition to critical period plasticity: inhibition selectively suppresses spontaneous activity. Neuron 80, 51–63. 31. Tasic, B., Menon, V., Nguyen, T.N., Kim, T.K., Jarsky, T., Yao, Z., Levi, B., Gray, L.T., Sorensen, S.A., Dolbeare, T., et al. (2016). Adult mouse cortical cell taxonomy revealed by single cell transcriptomics. Nat. Neurosci. 19, 335–346. 52. Ben-Ari, Y., and Spitzer, N.C. (2010). Phenotypic checkpoints regulate neuronal development. Trends Neurosci. 33, 485–492. 53. Cardin, J.A. (2018). 332 Current Biology 31, 322–333, January 25, 2021 Article Article ll OPEN ACCESS 65. Hammock, E.A.D., and Young, L.J. (2006). Oxytocin, vasopressin and pair bonding: implications for autism. Philos. Trans. R. Soc. Lond. B Biol. Sci. 361, 2187–2198. 58. Wosniak, M.E., Kirchner, J.H., Chao, L.-Y., Zabouri, N., Lohmann, C., and Gjorgjieva, J. (2020). Adaptive spontaneous activity in the developing vi- sual cortex. bioRxiv. https://doi.org/10.1101/2020.07.30.229559. 66. Insel, T.R., O’Brien, D.J., and Leckman, J.F. (1999). Oxytocin, vaso- pressin, and autism: is there a connection? Biol. Psychiatry 45, 145–157. 59. Guzzetta, A., Baldini, S., Bancale, A., Baroncelli, L., Ciucci, F., Ghirri, P., Putignano, E., Sale, A., Viegi, A., Berardi, N., et al. (2009). Massage accel- erates brain development and the maturation of visual function. J. Neurosci. 29, 6042–6051. 67. Muscatelli, F., Desarmenien, M.G., Matarazzo, V., and Grinevich, V. (2018). Oxytocin signaling in the early life of mammals: link to neurodeve- lopmental disorders associated with ASD. Curr. Top. Behav. Neurosci. 35, 239–268. 60. Che, A., Babij, R., Iannone, A.F., Fetcho, R.N., Ferrer, M., Liston, C., Fishell, G., and De Marco Garcı´a, N.V. (2018). Layer I interneurons sharpen sensory maps during neonatal development. Neuron 99, 98–116.e7. 68. Evangelidis, G.D., and Psarakis, E.Z. (2008). Parametric image alignment using enhanced correlation coefficient maximization. IEEE Trans. Pattern Anal. Mach. Intell. 30, 1858–1865. 61. Golshani, P., Gonc¸ alves, J.T., Khoshkhoo, S., Mostany, R., Smirnakis, S., and Portera-Cailliau, C. (2009). Internally mediated developmental de- synchronization of neocortical network activity. J. Neurosci. 29, 10890– 10899. 69. Diesmann, M., and Gewaltig, M.-O. (2002). NEST: An Environment for Neural Systems Simulations (Beitr€age zum Heinz-Billing-Preis), pp. 43–70. 62. Rochefort, N.L., Garaschuk, O., Milos, R.I., Narushima, M., Marandi, N., Pichler, B., Kovalchuk, Y., and Konnerth, A. (2009). Sparsification of neuronal activity in the visual cortex at eye-opening. Proc. Natl. Acad. Sci. USA 106, 15049–15054. 70. Pologruto, T.A., Sabatini, B.L., and Svoboda, K. (2003). ScanImage: flex- ible software for operating laser scanning microscopes. Biomed. Eng. Online 2, 13. 71. Battefeld, A., Popovic, M.A., van der Werf, D., and Kole, M.H.P. (2019). A versatile and open-source rapid LED switching system for one-photon im- aging and photo-activation. Front. Cell. Neurosci. 12, 530. 63. Cheyne, J.E., Zabouri, N., Baddeley, D., and Lohmann, C. (2019). Spontaneous activity patterns are altered in the developing visual cortex of the Fmr1 knockout mouse. Front. Neural Circuits 13, 57. 72. Chen, T.-W., Wardill, T.J., Sun, Y., Pulver, S.R., Renninger, S.L., Baohan, A., Schreiter, E.R., Kerr, R.A., Orger, M.B., Jayaraman, V., et al. (2013). Current Biology 31, 322–333, January 25, 2021 333 ACKNOWLEDGMENTS Inhibitory interneurons regulate temporal precision and correlations in cortical circuits. Trends Neurosci. 41, 689–700. 32. Adesnik, H., Bruns, W., Taniguchi, H., Huang, Z.J., and Scanziani, M. (2012). A neural circuit for spatial summation in visual cortex. Nature 490, 226–231. 54. Giridhar, S., Doiron, B., and Urban, N.N. (2011). Timescale-dependent shaping of correlation by olfactory bulb lateral inhibition. Proc. Natl. Acad. Sci. USA 108, 5843–5848. 33. Leighton, A.H., Houwen, G.J., Cheyne, J.E., Maldonado, P.P., De Winter, F., and Lohmann, C. (2020). Control of spontaneous activity patterns by inhibitory signaling in the developing visual cortex. bioRxiv. https://doi. org/10.1101/2020.02.21.959262. 55. Arevian, A.C., Kapoor, V., and Urban, N.N. (2008). Activity-dependent gating of lateral inhibition in the mouse olfactory bulb. Nat. Neurosci. 11, 80–87. 34. van Versendaal, D., and Levelt, C.N. (2016). Inhibitory interneurons in vi- sual cortical plasticity. Cell. Mol. Life Sci. 73, 3677–3691. 56. Friedrich, R.W., and Laurent, G. (2001). Dynamic optimization of odor rep- resentations by slow temporal patterning of mitral cell activity. Science 291, 889–894. 35. Gonchar, Y., Wang, Q., and Burkhalter, A. (2008). Multiple distinct sub- types of GABAergic neurons in mouse visual cortex identified by triple im- munostaining. Front. Neuroanat. 1, 3. 57. Xu, H.-P., Burbridge, T.J., Chen, M.-G., Ge, X., Zhang, Y., Zhou, Z.J., and Crair, M.C. (2015). Spatial pattern of spontaneous retinal waves instructs retinotopic map refinement more than activity frequency. Dev. Neurobiol. 75, 621–640. 36. Tirko, N.N., Eyring, K.W., Carcea, I., Mitre, M., Chao, M.V., Froemke, R.C., and Tsien, R.W. (2018). Oxytocin transforms firing mode of CA2 hippo- campal neurons. Neuron 100, 593–608.e3. 332 Current Biology 31, 322–333, January 25, 2021 332 Current Biology 31, 322–333, January 25, 2021 Article Ultrasensitive fluorescent proteins for imaging neuronal activity. Nature 499, 295–300. 64. Gonc¸ alves, J.T., Anstey, J.E., Golshani, P., and Portera-Cailliau, C. (2013). Circuit level defects in the developing neocortex of fragile X mice. Nat. Neurosci. 16, 903–909. Article ll OPEN ACCESS ll OPEN ACCESS STAR+METHODS KEY RESOURCES TABLE STAR+METHODS KEY RESOURCES TABLE REAGENT or RESOURCE SOURCE IDENTIFIER 0Bacterial and Virus Strains pAAV1-hSyn-DIO-hM4D(Gi)- mCherry 33 N/A pAAV1.Syn.GCaMP6s. WPRE.SV40 UPenn viral core AV-1-PV2824 Chemicals, Peptides, and Recombinant Proteins Oregon Green 488 BAPTA-1 AM Invitrogen Thermo Fisher Scientific #O6807 Oxytocin Sigma O6379 desGly-NH2,d(CH2)5[D- Tyr2,Thr4]OVT Synthesized and given by Dr. Maurice Manning, University of Toledo30 N/A Clozapine N-oxide Tocris #0444 Clozapine Tocris #4936 SR95531 Tocris #1262 NBQX Tocris #1044 D-AP5 Tocris #0103 TTX Tocris #1078 Critical Commercial Assays RNAscope 2.5HD Duplex Assay Advanced Cell Diagnostics #322430 Experimental Models: Organisms/Strains Mouse: C57B/6J Janvier N/A SstCre The Jackson Laboratory 013044 Gad2Cre The Jackson Laboratory 010802 Gt(ROSA)26SorCAG-tdTomato The Jackson Laboratory 007908 Oligonucleotides Oxtr Advanced Cell Diagnostics #411101-C2 Slc17a7, VGLUT1 Advanced Cell Diagnostics #416631 Gad1 Advanced Cell Diagnostics #400951 Sst Advanced Cell Diagnostics #404631 Recombinant DNA pCAGGS-DsRed Gift from Dr. Christiaan Levelt N/A pCAGGS-GCaMP6s Gift from Dr. Christiaan Levelt N/A Software and Algorithms Enhanced correlation coefficient algorithm 68 N/A NEST 69 RRID:SCR_002963 Model simulations This paper https://github.com/ comp-neural-circuits/ OTmodel LabView National Instruments LabView, RRID:SCR_014325 (Continued on next page) (Continued on next page) e1 Current Biology 31, 322–333.e1–e5, January 25, 2021 Article ll OPEN ACCESS Continued REAGENT or RESOURCE SOURCE IDENTIFIER ScanImage http://scanimage. vidriotechnologies.com/ display/SIH;jsessionid= 06CBF1F1626C33338 4D74630886127FF70 ScanImage, RRID:SCR_014307 NIS-Elements Nikon (NIS-Elements, RRID:SCR_014329 ImageJ https://imagej.net/ ImageJ, RRID:SCR_003070 MATLAB MathWorks MATLAB, RRID:SCR_001622 Clampfit Molecular Devices pClamp, RRID:SCR_011323 AxoGraph Axograph Scientific Axograph, RRID:SCR_014284 IGOR Pro Wave Metrics IGOR Pro, RRID:SCR_000325 Prism 7 GraphPad GraphPad Prism, RRID:SCR_002798 Other TEAMSTER (Open-source rapid LED switching system for one-photon imaging and photo-activation) 71 https://github.com/Kolelab/ Image-analysis OPEN ACCESS Article Data and Code Availability The datasets generated during this study have not been deposited in a public repository but are available from the Lead Contact on request. This study used standard, custom-built MATLAB programmed scripts that are available from the Lead Contact upon request. The code used for the simulations is available at https://github.com/comp-neural-circuits/OTmodel. Materials Availability This study did not generate new unique reagents. Lead Contact Further information and requests for resources and reagents may be directed to and will be fulfilled by the Lead Contact, Christian Lohmann, c.lohmann@nin.knaw.nl. Animal All experimental procedures were approved by the institutional animal care and use committee of the Royal Netherlands Academy of Arts and Sciences and in agreement with the European Community Directive 2010/63/EU and with the Institutional Animal Care and Use Committee at Florida State University in accordance with state and federal guidelines (Guide for the Care and Use of Laboratory Animals of the National Institutes of Health). We used neonatal C57BL/6J, SST-Cre, SST-Cre;Rosa26-TdTomato and GAD2-Cre;R- osa26-TdTomato males and females mice from postnatal day 9 to 14 (P9-14). The SST-Cre;Rosa26-TdTomato and GAD2-Cre;R- osa26-TdTomato lines were generated by crossing the reporter Rosa26-TdTomato line (The Jackson Laboratory, 007908) with either the SST-Cre (The Jackson Laboratory, 013044) or the GAD2-Cre (The Jackson Laboratory, 010802) lines. Neonatal pups were housed with one mother, with exception of pups coming from in utero electroporation. They were housed with two mothers and the nest trimmed to 6 pups to facilitate the caring behavior of the mothers. Animals were kept in a 12h-12h light/dark cycle with food and water ad libitum. All the experiments were performed during the light cycle. No effects related to sex were observed. No animal was excluded from the analysis. Current Biology 31, 322–333.e1–e5, January 25, 2021 e2 Article ll OPEN ACCESS 2-photon imaging Bolus load of the calcium indicator Oregon Green 488 BAPTA-1 AM (OGB-1, Invitrogen) was performed as described7. Imaging was performed by using a two-photon microscope (MOM, Sutter, or A1RMP, Nikon) and a mode-locked Ti:Sapphire laser (MaiTai, Spectra Physics or Chamaleon, Coherent, l = 810 nm). Consecutive xyt-stacks were acquired at a frame rate of 4-7 Hz (pixel size 0.3 - 0.6 mm) through a 40x (0.8 NA, Olympus) or a 16x (0.8 NA, Nikon) water-immersion objective, controlled by ScanImage70 or NIS-Elements AR4.51.00 software (Nikon). For in vivo experiments, oxytocin (1 mM, Sigma) and the oxytocin receptor antagonist (desGly-NH2,d(CH2)5[D-Tyr2,Thr4]OVT, 250 mM, synthesized and kindly donated by Dr. Maurice Manning, University of Toledo) was diluted in cortex buffer solution7 and applied topically at the craniotomy. The craniotomy was filled with approximately 300 ml of solution and that volume was kept con- stant until the end of the experiment. In utero electroporation and surgery In utero electroporation was performed as described previously23. To perform calcium imaging of layer 2/3 pyramidal cells, GCaMP6s was cloned into pCAGGS (Addgene plasmid 4075372) and used in combination with DsRed in pCAGGS for visualization (gift from Christiaan Levelt). Pups were in utero electroporated at embryonic day (E) 16.5 after injection of the GCaMP6s (2 mg/ml) and DsRed (1 mg/ml) vectors into the ventricles. Electrode paddles were positioned to target the subventricular zone and 50 V pulses of 50 ms duration were applied. For in vivo experiments, surgery for craniotomy was performed as described previously7,33. Pups were kept at 36-37C and anes- thetized with 2% isoflurane and lidocaine was applied into the skin before neck muscle removal. A head bar was fixed above the V1/ S1 region. Isoflurane was dropped to 0.7% before the imaging session. This lightly anesthetized state, which is characterized by rapid and shallow breathing and a relatively high heart rate, was maintained throughout the imaging session. During experiments in the absence of anesthesia, pups were kept undisturbed in the dark and covered by a custom-made holder that prevents heat loss and mimic the conditions in the nest, for one hour before the imaging session started. The welfare of the pup was monitored to mini- mize distress during the whole imaging session. Virus injection Virus injections were performed at P0-1. Virus injected were pAAV1-Syn-GCaMP6s (AV-1-PV2824, UPenn viral core) and pAAV1- hSyn-DIO-hM4D(Gi)-mCherry (produced by Fred Winter33). SST-Cre neonatal mice were anesthetized by cold-induced hypothermia and kept cold in a stereotactic frame for pups (RWD Life Science). Stereotactic injections targeting V1 were performed with a micro- injection pipet (Nanoject II, Drummond; volume 27 nl; mix of 1:1 AAV1-hSyn-DIO-hM4D(Gi)-mCherry and AAV1-Syn-GCaMP6; from Bregma in mm: 0.3 posterior, 1.4 lateral). Immediately after injection, pups were kept warm on a heating pad and placed back to their mother after they awoke from anesthesia. Wide-field imaging In utero electroporated or virus injected pups were used for calcium imaging of visual and somatosensory cortex. Calcium events were recorded with a Movable Objective Microscope (MOM, Sutter Instrument). Time-lapse recordings were acquired with a 4x objective (0.8 NA, Olympus) and blue light excitation from a Xenon Arc lamp (Lambda LS, Sutter Instrument Company). A CCD cam- era (Evolution QEi, QImaging) was controlled by custom-made LabVIEW (National Instruments) based software and images were ac- quired at a frame rate of 20 Hz. s injected subcutaneously (0.5 mg/kg) and oxytocin was applied five minutes after clozapine injection. Clozapine (Tocris) was injected subcutaneously (0.5 mg/kg) and oxytocin was applied five m Clozapine (Tocris) was injected subcutaneously (0.5 mg/kg) and oxytocin was applied five minutes after clozapine injection. METHOD DETAILS In utero electroporation and surgery Patch-clamp experiments Acute 300 mm coronal slices of the visual or somatosensory cortex were dissected between P9-P14. Pups were sacrificed by decap- itation and their brains were immersed in ice-cold cutting solution (in mM): 2.5 KCl, 1.25 NaH2PO4, 26 NaHCO3, 20 Glucose, 215 Su- crose, 1 CaCl2, 7 MgCl2 (Sigma), pH 7.3-7.4, bubbled with 95%/5% O2/CO2. Slices were obtained with a vibratome (Microm HM 650V, Thermo Scientific) and subsequently incubated at 34C in artificial cerebrospinal fluid (ACSF, in mM): 125 NaCl, 3.5 KCl, 1.25 NaH2PO4, 26 NaHCO3, 20 Glucose, 2 CaCl2, 1 MgCl2 (Sigma), pH 7.3-7.4. After 45 minutes, slices were transferred to the elec- trophysiology setup, kept at room temperature and bubbled with 95%/5% O2/CO2. For patch-clamp recordings, slices were trans- ferred to a recording chamber and perfused (3 ml/min) with ACSF solution bubbled with 95%/5% O2/CO2 at 34C. Layer 2/3 pyramidal cells and interneurons were identified using an IR-DIC video microscope (Olympus BX51WI). GAD2+ and SST+ interneurons were identified by the TdTomato protein fluorescence from the transgenic mice GAD2-Cre;Rosa26-TdTomato and SST- Cre;Rosa26-TdTomato, respectively. Quick change between bright-field imaging and epifluorescence was achieved using a foot- switch device TEAMSTER71. Whole-cell voltage or current-clamp recordings were made with a MultiClamp 700B amplifier (Molecular Devices), filtered with a low pass Bessel filter at 10 kHz and digitized at 20-50 kHz (Digidata 1440A, Molecular Devices). Series resis- tance was assessed during recordings and neurons showing a series resistance > 30 MU or a change > 30% were discarded. Digi- tized data were analyzed offline using Clampfit 10 (Molecular Devices), Igor (WaveMetrics) and AxoGraph (Axograph Scientific). e3 Current Biology 31, 322–333.e1–e5, January 25, 2021 Article ll OPEN ACCESS Spontaneous and miniature IPSCs were recorded at a holding potential of 10 mV with glass pipettes (3-6 MU) containing (in mM): 115 CsCH3SO3, 10 HEPES, 20 CsCl, 2.5 MgCl2, 4 ATP disodium hydrate, 0.4 GTP sodium hydrate, 10 phosphocreatine disodium hydrate, 0.6 EGTA (Sigma), pH 7.3. For sIPSC recordings during selective silencing of SST+ interneurons, clozapine N-oxide (CNO) (10 mM, Tocris) was administered 1 minute prior to oxytocin (1 mM, Sigma). mIPSCs were recorded in the presence of tetro- dotoxin (0.5 mM, Tocris). The oxytocin receptor antagonist desGly-NH2,d(CH2)5[D-Tyr2,Thr4]OVT (50 mM, synthesized and kindly donated by Dr. Maurice Manning, University of Toledo) was applied for 5-10 minutes before oxytocin wash-in. Patch-clamp experiments sEPSCs were re- corded at a holding potential of 60 mV (with junction potential correction) with an intracellular solution containing (in mM): 122 po- tassium gluconate, 10 HEPES, 13 KCl, 10 phosphocreatine disodium hydrate, 4 ATP magnesium salt, 0.3 GTP sodium hydrate (Sigma), pH 7.3. Oxytocin-induced currents in GAD2+ and SST+ interneurons were recorded at a holding potential of 60 mV (with junction potential correction) in the presence of 10 mM SR95531, 10 mM NBQX, 50 mM D-AP5 (Tocris). Current-clamp recordings of SST+ interneurons were performed using the same KGluconate-based intracellular solution and in the presence of the synaptic blockers mentioned above. After breaking the seal, variable current injection was applied to keep the cells at 60 mV. The injected current was kept constant from the time of oxytocin wash-in. Model We simulated a large-scale computational model of the visual cortex37 in the NEST framework69. We focused only on modeling the cortical network of excitatory and inhibitory neurons with 25% of the inhibitory population corresponding to SST+ neurons in L2/3, receiving excitatory input from the thalamus. To achieve network activity similar to that described for the developing cortex7,62, we adjusted the intrinsic membrane properties and synaptic weights in the model based on measurements from the present study (Table S1) and applied an external current of 50 pA (to excitatory neurons) or 40 pA (to SST+ interneurons) and a sinusoidal background input to the excitatory population to generate spontaneous activity. The oxytocin effect was modeled by increasing the resting membrane potential of SST+ interneurons from 60.8 mV to 56.3 mV as the change observed in our experiments (Figure 6A). After simulating the system for 60 s in baseline condition, we modeled application of oxytocin and simulated again for 60 s. Correlations are computed between the voltage traces of excitatory units. RNAscope Fresh frozen brain tissue from C57BL/6J mice was sectioned in the sagittal plane at 20 mm in 6 series on SuperFrost Plus microscope slides and stored at 80C until further processing. RNA transcripts were detected with RNAscope 2.5HD Duplex Assay (Cat. No. 322430, Advanced Cell Diagnostics (ACD), Hayward, CA). Synthetic oligonucleotide probes complementary to the nucleotide sequence 1198 – 2221 of Oxtr (NM_001081147.1; ACD Cat. No. 411101-C2), 464 - 1415 of Slc17a7 (VGLUT1; NM_182993.2; ACD Cat. No. 416631), 62 – 3113 of Gad1 (NM_008077.4; ACD Cat. No. 400951) and 18 – 407 of Sst (NM_009215.1; ACD Cat. No. 404631) were used. Slides were fixed for 2 hours in ice cold 4% paraformaldehyde (pH 9.5) followed by increasing concentrations of ethanol and dehydration in 100% ethanol overnight at 20C. Slides were air-dried for 10 minutes and boiled for 5 minutes in a target retrieval solution (ref. 322001, ACD), followed by 2 room temperature water rinses and a rinse in 100% ethanol. Slides were air-dried, after which targeted sections were incubated with Protease Plus solution (ref. 322331, ACD) for 15 minutes at 40C, fol- lowed by room temperature water rinses. These prepared slides were then probed for 2 hours with individual probe mixtures (Oxtr in the red channel 2 and the other probes in the blue-green channel 1) at 40C. Unbound probes were rinsed off in wash buffer and slides were stored overnight in 5X SSC at room temperature. Signal amplification and detection were performed using the detailed instructions provided in the RNAscope 2.5HD Duplex Assay. Sections were counterstained with Gill’s hematoxylin (Amer- ican Mastertech Scientific, Inc. Lodi, CA) and coverslipped with Vectamount (Vector Laboratories, Inc. Burlingame, CA). Images were captured with brightfield microscopy (Keyence BZ-X710, Keyence Corp., Osaka, Japan). Wide-field imaging analysis Network events were detected automatically. First, DF/F0 stacks were generated using a moving average across 500 frames as F0. The detection threshold was 12% DF/F0, which was at least 3x larger than the standard deviation of the noise during inactivity for all recordings. Pixels below threshold were reduced to zero. Network events were defined as groups of at least 300 non-zero pixels that were connected in time and/or space. Since the frame rate was 20 Hz and the pixel size 7.68 mm (area covered by 1 pixel: 59 mm2), this criterion included events of e.g., > 1 s duration that covered on average > 885 mm2 of cortical surface. Since this criterion was chosen empirically, we investigated how robust our findings were with respect to this criterion. We performed analyses where we varied the total number of connected pixels that defined a network event on a subset of the data. We found that the number of detected events and the changes observed in frequency after oxytocin application were very robust across different pixel numbers between 200 and 800 pixels (not shown). Since wide-field microscopy is inherently prone to scattered light, we found that the area that network events covered across the cortex was overestimated when we used the 12% cutoff. Therefore, we restricted the area to those pixels that reached 67% of the maximal DF/F0 value for each event (Figure S6). Recordings from un-anaesthetized animals showed increased movement artifacts. Therefore, we restricted our analysis to fre- quency and amplitude of network events in traces generated from the entire area of V1. Traces were long-pass filtered to remove high-frequency movement artifacts. Network events were automatically detected using MATLAB’s ‘‘Find peaks’’ function where the parameters prominence and peak were optimized for detecting events during the baseline period and kept constant throughout the experiment. Electrophysiological analysis p y g y m/sIPSCs and sEPSCs were detected using an Igor-based tool SpAcAn (Igor Pro 7, WaveMetrics). Frequency timelines of postsyn- aptic currents were built by calculating the frequency of 50-or 90 s bins. The 20%–80% rise time was calculated for each IPSC event and the rise rate was determined as amplitude/rise time (pA/ms). Excitability of SST+ interneurons was assessed with a one-step ramp protocol, from 100 pA to 140 pA at a rate of 96 pA/second. Single action potentials (APs) were elicited by injecting moderate pulses of current (< 1 nA, < 15 ms). Changes in membrane potential upon oxytocin treatment were calculated as the voltage differ- ence between the trace exhibiting the peak effect and the last trace of baseline condition. A minority of cells that did not exhibit a depolarization (6%) were discarded for subsequent analyses. A voltage timeline was built by calculating the baseline membrane po- tential of 45 s bins. For analysis of SST+ interneuron excitability, the duration of the ramp was divided into 175-milisecond bins and the mean inter-spike interval (ISI) was calculated for each period bin. Then, the instantaneous frequency (ISI-1) was plotted against the mean current injected within the same bin. AP features were determined as follows: (1) overshoot was quantified as the amplitude of the AP above 0 mV. (2) Amplitude was calculated as the voltage difference between the peak of the AP and its threshold. (3) Width was determined at half the amplitude of the AP. (4) DTime was described as the time difference between the onset of pulse injection and the time point when the membrane potential reached the action potential threshold. (5) dVdt-1 was defined as the first derivative of the voltage trace with respect to time. 2-photon imaging analysis For the matrix correlation analysis, we computed the squared distance between the baseline matrix, cBL ij , computed for the entire baseline period of 45 minutes, and the correlation matrix computed from a shifting 7-minute slice centered at time point t, ct ij, and then summing over all the element-wise differences of all matrix entries, MSD = P ij ðct ij  cBL ij Þ 2 . To remove any potential drift that occurs already during the baseline and that might distort the MSD analysis, we performed a linear regression on the baseline MSD and sub- tracted the linear contributions from all time points. To further pool across multiple animals, we normalized the squared distances by the mean and standard deviation of the baseline period. j already during the baseline and that might distort the MSD analysis, we performed a linear regression on the baseline MSD and sub- tracted the linear contributions from all time points. To further pool across multiple animals, we normalized the squared distances by the mean and standard deviation of the baseline period. 2-photon imaging analysis Images were analyzed with ImageJ (NIH) and custom-written MATLAB scripts (MathWorks) as described previously63. First, to re- move movement artifacts and align all recordings we performed an image alignment step based on the enhanced correlation coef- ficient algorithm68. DF/F0 stacks were generated by subtracting and dividing each frame by the mean fluorescence (F0). Regions of interest (ROIs) were placed on cells that showed clear activity and were visible in all recordings. Glial cells in the field of view showed elevated basal intensity and were not active. All included ROIs were neuronal. DF/F0 traces were obtained by calculating the mean intensity within the ROI for each frame. Increases in fluorescence intensity, which reflect increases in the intracellular calcium con- centration due to action potential firing, were then detected automatically for all ROIs and subsequently verified manually. The detec- tion threshold was adjusted for each experiment (at least 2x the standard deviation of the signal in the absence of events) but re- mained the same within an experiment. Pearson correlation coefficients were computed from the DF/F0 stacks. The total number of pairs of cells (computed as N(N – 1) /2) was balanced across conditions (oxytocin – 8806 pairs; cortex buffer – 8023 pairs). In Figure 2E each x-coordinate corresponds to a window of length 7 minutes around the time point. The y-coordinate of the line is computed as the average across all animals of the condition over the correlation coefficients computed from the window. The shaded area is the standard error of the mean (computed as bs= ffiffiffiffi N p , where bs is the estimated standard deviation over animals and N is the number of animals). In Figure 2F, we averaged the Current Biology 31, 322–333.e1–e5, January 25, 2021 e4 Current Biology 31, 322–333.e1–e5, January 25, 2021 e4 ll OPEN ACCESS Article A i l correlation coefficients computed from the windows over all animals and time points before or after oxytocin application. The filled contour plot was made by plotting pairwise correlations after oxytocin (average of 40 minutes period after oxytocin) against baseline correlations (average of 40 minutes period before oxytocin). correlation coefficients computed from the windows over all animals and time points before or after oxytocin application. The filled contour plot was made by plotting pairwise correlations after oxytocin (average of 40 minutes period after oxytocin) against baseline correlations (average of 40 minutes period before oxytocin). RNAscope analysis p y Quantification was done on the 40x images. The total number of cells was determined by the nucleus visualization given by Gill’s hematoxalin staining. Oxtr+/VGLUT1+/Gad1+ neurons were manually identified and counted with ImageJ. Statistics All data are shown as mean ± SEM. The number of animals and the test used for each analysis is specified in the Results section. To determine statistical differences we used Prism 7 (GraphPad). Sets of data R 6 were tested for normality with a Shapiro-Wilk test, then a paired or unpaired t test was applied for two-group comparisons. Comparisons between more than two groups were per- formed with one or two-way ANOVAs. For not normally distributed data or data < 6, the non-parametric Wilcoxon and Mann-Whitney tests were applied for paired or unpaired experiments, respectively, for two-group comparisons. Datasets with more than two groups were analyzed using the Kruskal-Wallis and Friedman test. e5 Current Biology 31, 322–333.e1–e5, January 25, 2021
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The Impact of Green Technology Innovation on Capital Cost of Heavy Polluting Enterprises: The Mediating Effect of Carbon Performance
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∗e-mail: trieumyan@gmail.com © The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (https://creativecommons.org/licenses/by/4.0/). The Impact of Green Technology Innovation on Capital Cost of Heavy Polluting Enterprises: The Mediating Effect of Carbon Performance Liming Zhang1, Jingyi Li1, Kuankuan Luo1, and Thi My An Trieu2,∗ Liming Zhang1, Jingyi Li1, Kuankuan Luo1, and Thi My An Trieu2,∗ 1Business School, Sichuan University, Chengdu 610065, People’s Republic of China 2Department of Chinese Language, Thanh Dong University, Hai Duong Province 34000, Socialist Re- public of Vietnam Liming Zhang1, Jingyi Li1, Kuankuan Luo1, and Thi My An Trieu2,∗ 1Business School, Sichuan University, Chengdu 610065, People’s Republic of China 2Department of Chinese Language, Thanh Dong University, Hai Duong Province 34000, Socialist Re- public of Vietnam 1Business School, Sichuan University, Chengdu 610065, People’s Republic of China usiness School, Sichuan University, Chengdu 610065, People’s Republic of China 2Department of Chinese Language, Thanh Dong University, Hai Duong Province 34000, Socialist public of Vietnam Abstract. Under the background of the carbon peaking and carbon neutrality goals proposed in 2020, making heavy polluting enterprises realize that low- carbon measures can bring enough economic benefits is conducive to enhancing their enthusiasm to adopt green behaviors. Using data from 320 listed compa- nies in heavily polluting industries from 2006 to 2019 as samples, our study used multiple linear regression to explore the relationship between green tech- nology innovation, carbon performance, board characteristics and cost of capi- tal. Based on these data, we draw the following conclusions: green technology innovation and carbon performance are significantly negatively correlated with capital cost, carbon performance plays a mediating role in the relationship be- tween green technology innovation and capital cost, and board characteristics play a moderating role in the relationship between green technology innova- tion and carbon performance. These conclusions bring some implications for enterprises to develop and implement low-carbon measures and reduce capital cost. Keywords: Green manufacturing, Technology and innovation, Carbon performance, Capital cost, Characteristics of board of directors. E3S Web of Conferences 409, 01016 (2023) ICMSEM 2023 E3S Web of Conferences 409, 01016 (2023) ICMSEM 2023 https://doi.org/10.1051/e3sconf/202340901016 1 Introduction According to the Vision 2035, we will continue to innovate in technology, and promote the interaction between technology, finance and industry. The 19th National Congress stressed that to make ecological progress, we need to establish the economic system with green, low- carbon and circular development, and comprehensively promote sustainable technological innovation. Green technology innovation can effectively help enterprises break through diffi- culties and achieve long-term development. Heavy polluting enterprises face greater pressure of legitimacy. The active practice of green innovation concepts by enterprises is conducive to the coordinated development of economy and ecology. In the past, many heavy polluters ignored the environmental costs and made super-high profits. However, faced with the increasingly serious environmental problems, the impact of government environmental policies has become an unavoidable topic in the decision-making of enterprises and investors. The investment and production activities of enterprises will be directly constrained by environmental policies. Investors tend to take green innovation E3S Web of Conferences 409, 01016 (2023) ICMSEM 2023 https://doi.org/10.1051/e3sconf/202340901016 and carbon performance into account when investing in heavily polluting industries. Under environmental pressure, heavy polluting enterprises which are no matter forced to survive passively or adapt to policy changes actively, need to make changes such as updating outdated equipment or adjusting development strategies. Such changes in investment direction will affect the cost of capital of enterprises to a large extent. and carbon performance into account when investing in heavily polluting industries. Under environmental pressure, heavy polluting enterprises which are no matter forced to survive passively or adapt to policy changes actively, need to make changes such as updating outdated equipment or adjusting development strategies. Such changes in investment direction will affect the cost of capital of enterprises to a large extent. Under the background of carbon peaking and carbon neutrality goals and national eco- nomic transformation, how does the green technology innovation of heavy polluting enter- prises affect the capital cost? What role does carbon performance play? What effect does the characteristics of the board of directors play in the process of carrying out environmental responsibilities of heavy polluting enterprises? These problems are the core issues of great concern in this study. We constructed panel data of heavy polluting enterprises from 2006 to 2019 to explore the relationship between green technology innovation, carbon performance and capital cost of heavy polluting enterprises. 1 Introduction The main contributions of this work are: (1) In this study, carbon performance is in- troduced as the mediating variable between green technology innovation and capital cost, which increases the degree of information transparency and exposes the "black box" between green technology innovation and capital cost of heavily polluting enterprises. (2) We explore how two types of green technology innovation affect the decisions of two different types of investors which broadens the research perspective on the relationship between green technol- ogy innovation and capital cost. (3) From the three dimensions of board characteristics, we explore the influence of internal governance on low-carbon strategy and behavior of heavy polluting enterprises, which is of enlightening significance for enterprise management prac- tice. The rest of this paper is organized as follows. Section 2 discusses relevant literature and develops our hypotheses. Section 3 describes the data, measure and models. Section 4 presents the results from our analysis. Section 4.5 summarizes the main conclusions and makes corresponding suggestions for governments and enterprises. 2.2 Green Technology Innovation and Carbon Performance Enterprises actively carry out carbon emission reduction activities in response to the na- tional call, which puts forward higher requirements for technological innovation. Meanwhile, through green technological innovation, carbon emissions can be effectively reduced and car- bon performance can be promoted. Dong et al. (2022) found that green technology inno- vation can promote economic development and urbanization process, thus improving carbon emission efficiency [5]. Green technology innovation affects carbon performance from three aspects: green process innovation, green product innovation and end-treatment technology innovation [1]. First of all, through green process innovation, enterprises optimize produc- tion process, improve energy efficiency, use clean energy, optimize energy structure, reduce carbon emissions from the source, and improve environmental performance. Secondly, the use of advanced technology to develop and produce green products, improve product design, product quality and packaging design, so that the product can be recycled and recover the residual value of it, and then form a green circular economy, relieve the legal pressure of enterprises. Finally, innovate end treatment technology, update pollution control equipment or change the way of pollutant treatment to realize harmless emissions or reducing emissions of pollutants and then promoting sustainable development. Therefore, we predict the following: Hypothesis 2. Green technology innovation will be positively to carbon performance. Therefore, we predict the following: p g Hypothesis 1. Green technology innovation will be negative to enterprise capital cost. 2.1 Green Technology Innovation and Capital Cost Green product innovation labels products as “green”, which satisfies consumers’ require- ments for corporate environmental responsibility, increases product premium, enhances cus- tomer loyalty, and accumulates social capital for enterprises [1]. The product sales situation is reflected in the financial statements, which conveys to creditors that the enterprise has good profitability, which can effectively reduce creditors’ borrowing risks and enhance their borrowing willingness. Companies are more willing to provide private information to banks than other investors. Therefore, creditors can obtain more information, reduce the degree of information asymmetry, and reduce the financing cost of borrowers [2]. The capital demand of technological innovation is great, the cycle is long and the un- certainty is high, which leads to the increase of enterprise risk and makes investors ask for higher financing costs [3]. Green technology innovation has problems of information asym- metry and moral hazard, which will lead to the increase of financing costs [4]. Enterprises improve production process, increase productivity and reduce cost through green process in- novation and also, they achieve differentiated development and expand market share through green product innovation. These ways of green technology innovation are all conducive to establishing a good reputation for the enterprise, enhancing its competitiveness, highlighting the enterprise’s good development prospects and strong ability to create value. At this time, equity investors have a strong investment intention for the enterprises. 2 https://doi.org/10.1051/e3sconf/202340901016 E3S Web of Conferences 409, 01016 (2023) ICMSEM 2023 2.3 Carbon Performance and Capital Cost Environmental performance is an important basis for creditors to evaluate enterprise risk and financial cash flow [6]. Carbon performance reflects the performance of enterprises’ environ- mental responsibility and the moral level of enterprises. Creditors usually take the moral level into consideration when evaluating enterprise credit risk [7]. Enterprises with good environ- mental performance can establish long-term relationships with stakeholders [8], gain their trust and support, and reduce litigation costs. The reduction of carbon emissions is conducive to establishing a good image for enterprises, reducing carbon risks and pollution control costs [9], thus reducing credit risks and gaining the trust of creditors, which is conducive to the signing of a loan agreement between both parties. National financial institutions strictly ex- amine the loan qualification of enterprises in heavily polluting industries, which puts forward further requirements on the carbon performance of enterprises [10]. Enterprises with good environmental performance are considered to have less investment risk, more trust from investors [2], and more hope to increase stock price and reduce capital cost. The signal transmission theory points out that information disclosure can convey the signal that enterprises actively fulfill their social responsibilities to the outside world, which is conducive to reducing the information asymmetry between enterprises and stakeholders, so that external stakeholders can grasp the operation and financial condition of enterprises. A good carbon performance level can set up a good image for enterprises, enable enterprises to form unique competitive advantages in the market, obtain more resources from the outside, improve corporate financial performance, increase corporate valuation and improve investor confidence. Therefore, we predict the following: Hypothesis 3. Carbon performance will be negative to capital cost. Hypothesis 3. Carbon performance will be negative to capital cost. 3 https://doi.org/10.1051/e3sconf/202340901016 E3S Web of Conferences 409, 01016 (2023) ICMSEM 2023 2.5 The Moderating Effect of Board Characteristics One of the purposes of the establishment of the board of directors is to alleviate agency conflicts and reduce agency costs. Independent directors are usually industry experts or suc- cessful people with strong professional ability, social responsibility and legal consciousness, so they can better exercise supervision and management functions. Because independent directors do not hold positions in the enterprise, their decisions are more independent and objective, and they are more able to make scientific decisions compared with internal direc- tors [11]. The higher the proportion of independent directors is, the more conducive it is to make decisions to achieve a win-win situation between the enterprise and the environment from the overall perspective of the enterprise, so as to actively support the enterprise’s green technology innovation, avoid the short-sighted behavior of the management to the maximum extent, and ensure the improvement of carbon performance. According to the high-level echelon theory, the cognitive ability, perception ability and value of management affect the strategic decision and organizational performance of an en- terprise. Female directors pay more attention to environmental pollution than male direc- tors. They are willing to participate in environmental protection activities, assume social responsibilities, solve environmental problems from the perspective of stakeholders, improve environmental performance, meet stakeholders’ expectations of corporate environmental re- sponsibility, and strengthen the relationship with stakeholders. The role of directors is to supervise the decisions and actions of management so as not to harm the long-term interests of company. Board interlocking occurs when board members hold board positions in different enterprises. However, each person’s time and energy are limited. Serving as a director of several enterprises will cause members to be unable to take care of these enterprises at the same time, and may be absent from the board of directors, weakening the supervision of the board of directors, and easily leading to the management violating shareholders’ rights and interests for their own interests, thus aggravating agency conflicts and increasing the principal-agent costs. The strategy of enterprises to improve carbon performance through green technology innovation requires a lot of time and energy to be deployed, and faces uncertain investment risks. Board interlocking will weaken the supervision effectiveness and investment prudence, and reduce the governance role of the board of directors. Therefore, we predict the following: Hypothesis 5. Board independence and board gender diversity will positively moderate the relationship between green technology innovation and carbon performance. 2.4 Mediating Effects of Carbon Performance Enterprises invest more in green technology innovation, which leads to greater risks, stronger uncontrollability and information asymmetry. Without disclosure of patent output or inno- vation performance, investors cannot know the situation of innovation investment, which is likely to lead to adverse selection and moral hazard and increase the uncertainty of invest- ment. Carbon performance can reliably reflect an enterprise’s innovation ability and social responsibility performance. The higher the level of green technology innovation is, the higher the enterprise’s carbon performance is. Creating a good social image can attract the atten- tion of investors and government policy support, so as to effectively integrate resources and reduce the cost of capital. Therefore, we predict the following: Hypothesis 4. Carbon performance plays an intermediary role in the relationship between green technology innovation and capital cost. 2.5 The Moderating Effect of Board Characteristics Board link- age will negatively moderate the relationship. 4 4 https://doi.org/10.1051/e3sconf/202340901016 E3S Web of Conferences 409, 01016 (2023) ICMSEM 2023 3.1 Data Source The A-share listed companies in the heavily polluting industries in China from 2006 to 2019 were selected as the research object, and the industry codes of the heavily polluting enter- prises were determined according to the Guidelines published by the MEP in 2010 and the industry codes from the National Bureau of Statistics. In order to ensure the quality of data, the following processing was carried out in this study: companies with ST and ST* were ex- cluded, companies without fourteen years of continuous data were excluded, and companies with serious data missing were excluded. After summarizing and collating the data, 4480 observed values of 320 heavy polluting enterprises were obtained. Data sources for our study include the CSMAR database, the official website of the People’s Bank of China, the State Intellectual Property Office of the People’s Republic of China (SIPO), the Carbon Emissions Trading Network and the China Statistical Yearbook. Winsorize each continuous variable by up or down 1% to reduce the impact of outliers. (1) Explained variables (1) Explained variables Cost of debt capital (Kd): Refer to Gong et al. (2021) and Bacha (2021) to express the cost of debt capital (Kd) in terms of the ratio of interest expense to total liabilities. Cost of Equity Capital (Ke): Currently commonly used methods to measure the cost of equity capital include capital asset pricing method (CAPM), multi-factor model method, historical average earnings method, dividend discount method and dividend growth model method, among which CAPM method and multi-factor model method are the most widely used and CAPM method is the most classic. CAPM method was applied to the research of Faysal et al. (2021) and Abu et al. (2022). We use CAPM method to calculate the cost of equity capital of listed companies in heavy pollution industries. Ke = Rf + β ∗(Rm −Rf). (1) (1) Total cost of capital (K): Using Kling et al. (2021) and Khanchel (2022) as reference, the simplified formula of weighted average cost of capital is adopted to calculate capital. Total cost of capital (K): Using Kling et al. (2021) and Khanchel (2022) as reference, the simplified formula of weighted average cost of capital is adopted to calculate capital. K = Kd ∗(1 −T) ∗D A + Ke ∗E A. (2) (2) Where, T is the corporate income tax rate, D is total liabilities, E is ownership equity, and A is total assets. (2) Explanatory variables Green technology innovation (GTI): Feng et al. (2022) measured corporate green in- novation by the number of green patent applications. In order to eliminate the right-biased distribution of green patent application data, this study added 1 to the number of green patent applications and took the natural logarithm. According to Ma et al. (2021), green invention patents are identified as disruptive green technology innovation and green utility patents as progressive green technology innovation. (3) Mediating variable Carbon performance (CP): Referring to Aslam (2021) and Peng (2021), the operating revenue of an enterprise’s unit carbon emissions is used to measure carbon performance. The 5 https://doi.org/10.1051/e3sconf/202340901016 E3S Web of Conferences 409, 01016 (2023) ICMSEM 2023 Table 1. Variable definition. (1) Explained variables Variable Type Variable Name Symbol Definition Explained Variable Total Cost of Capital K The cost of raising and using funds Cost of Debt Capital Kd The cost of bearing liabilities Cost of Equity Capital Ke The price of issuing common stock Explanatory Variable Green Technology Innovation GTI It is aimed at reducing environmental pollution and realizing sustainable development of ecological environment and social economy Disruptive Green Technology Innovation Inb The number of green invention patents Progressive Green Technology Innovation Inr The number of green utility patents Mediating Variable Carbon Performance CP The operating revenue of an enterprise’s unit carbon emissions Regulating Variable Independence of the Board of Directors BI Proportion of the number of independent directors in the scale of the board of directors Board Gender Diversity BGD The number of female directors as a percentage of board size Board Interlocking IB The logarithm of the number of listed companies in which the average interlocking board member concurrently serves Control Variable Enterprise Size Size The logarithm of the total assets of the business Growth Grow Current main business revenue growth rate Asset-liability Ratio Lev Ratio of total liabilities to total assets Return on Total Assets ROA Ratio of net profit to average annual total assets Profitability Profit The company’s gross profit margin on sales for the year Book Ratio B/M The ratio of book value of owners’ equity to market value Listing Years Age The logarithm of the distance between the reporting year and the listing year higher the value is, the better the carbon performance will be. Enterprise carbon emissions cannot be obtained directly, so we use operating costs and industrial carbon emissions to obtain. The formula for calculating carbon performance is shown below. higher the value is, the better the carbon performance will be. Enterprise carbon emissions cannot be obtained directly, so we use operating costs and industrial carbon emissions to obtain. The formula for calculating carbon performance is shown below. Carbon performance (CP) = enterprise revenue/(Enterprise operating cost * Industry car- bon emission/industry operating cost) (4) Regulating variables This study selects board independence, board gender diversity and board interlocking as three dimensions of board characteristics. The independence of the board of directors (BI) is expressed by the proportion of the number of independent directors in the scale of the board of directors. Board gender diversity (BGD) is expressed as the number of female directors as a percentage of board size; Board interlocking (IB) is expressed as the logarithm of the number of listed companies in which the average interlocking board member concurrently serves. 4.1 Descriptive Statistics The minimum value of capital cost (K) is 0.0101, the maximum value is 0.132, and the average value is 0.0598, indicating that the financing cost of some companies is high. The mean value of green technology innovation (GTI) is 0.485, the minimum value is 0, and the maximum value is 7.810. It can be seen that the green technology innovation level of listed companies with heavy pollution varies greatly, and some enterprises do not pay enough attention to green technology innovation, and their green technology innovation efforts need to be improved. The mean value of carbon performance (CP) is 6.016, the minimum value is 0.00652, the maximum value is 187.4, and the standard deviation is 12.00, indicating that the gap between the carbon performance of different enterprises is increasing. Many enterprises did not actively carry out carbon emission reduction management from 2006 to 2019, and there is still a large room for improvement of their carbon performance. 3.3 Model Setup Model Setup order to test our hypotheses, we employ the following econometric models: Kit = α0 + β1GTIit + β2S izeit + β3Growit + β4Levit + β5ROAit + β6Profitit+ +β7 B M it + β8Ageit + εit. (3) CPit = α0 + β1GTIit + β2S izeit + β3Growit + β4Levit + β5ROAit + β6Profitit+ β7 B Mit + β8Ageit + εit. (4) Kit = α0 + β1CPit + β2S izeit + β3Growit + β4Levit + β5ROAit + β6Profitit+ β7 B Mit + β8Ageit + εit. (5) Kit = α0 + β1CPit + β2GTIit + β3S izeit + β4Growit + β5Levit + β6ROAit + β7Profitit+ β7Pro fitit + β8 B Mit+β9Ageit+εit . (6) CPit = α0 + β1GTIit + β2BIit + β3BGDit + β4IBit + β5GTIit ∗BIit + β6GTIit ∗BGDit+ β7GTIit ∗IBit + β8S izeit + β9Growit + β10Levit + β11ROAit + β12Profitit+ β13 B Mit + β14Ageit + εit. (7) 3.3 Model Setup In order to test our hypotheses, we employ the following econometric models: Kit = α0 + β1GTIit + β2S izeit + β3Growit + β4Levit + β5ROAit + β6Profitit+ +β7 B M it + β8Ageit + εit. (3) Kit = α0 + β1GTIit + β2S izeit + β3Growit + β4Levit + β5ROAit + β6Profitit+ +β7 B M it + β8Ageit + εit. (3) (3) (6) CPit = α0 + β1GTIit + β2BIit + β3BGDit + β4IBit + β5GTIit ∗BIit + β6GTIit ∗BGDit+ β7GTIit ∗IBit + β8S izeit + β9Growit + β10Levit + β11ROAit + β12Profitit+ β13 B Mit + β14Ageit + εit. (7) (7) (5) Control variables The control variables selected in this study include enterprise size (S ize ), growth (Grow), asset-liability ratio (Lev), return on total assets (ROA), profitability (Profit), book ratio ( B M) and listing years (Age). The definition of all the above variables are shown in table 1. 6 6 E3S Web of Conferences 409, 01016 (2023) ICMSEM 2023 https://doi.org/10.1051/e3sconf/202340901016 E3S Web of Conferences 409, 01016 (2023) 4.2 Correlation Analysis In this study, Stata16.0 was used to test the correlation of sample data. The correlation coef- ficient between enterprise capital cost and green technology innovation is negative and sig- nificant at the level of 1%, which is consistent with hypothesis 1. The correlation coefficient between carbon performance and green technology innovation is significantly positive at the level of 10%, which is consistent with hypothesis 2. The correlation coefficient between car- bon performance and cost of equity capital and cost of debt capital is significantly negative at the level of 1%, which is consistent with hypothesis 3. The correlation coefficients of the main variables are all significantly correlated at 1% or 5% level, and the correlation coeffi- cients among all variables are less than 0.5, indicating that there is no serious multicollinearity problem in the model. 7 https://doi.org/10.1051/e3sconf/202340901016 E3S Web of Conferences 409, 01016 (2023) ICMSEM 2023 Table 2. Regression Analysis for Hypothesis 1 Model1 Model2 Model3 Modle4 Model5 Model6 Model7 Variable K Kd Kd Kd Ke Ke Ke GTI -0.031*** -0.063*** -0.036** (-2.64) (-4.58) (-2.08) Size -0.144*** -0.080*** -0.079*** -0.090*** -0.214*** -0.207*** -0.220*** (-8.34) (-3.93) (-3.87) (-4.40) (-8.95) (-8.61) (-9.33) Grow 0.041*** -0.006 -0.006 -0.005 0.007 0.007 0.007 -3.66 (-0.44) (-0.44) (-0.36) -0.46 -0.42 -0.48 Lev -0.719*** 0.298*** 0.297*** 0.301*** 0.088*** 0.086*** 0.090*** (-47.08) -14.89 -14.79 -15.04 -4.98 -4.82 -5.09 ROA -0.100*** -0.119*** -0.120*** -0.120*** -0.016 -0.017 -0.016 (-5.70) (-5.35) (-5.36) (-5.37) (-0.78) (-0.82) (-0.77) Profit -0.112*** -0.040** -0.039** -0.040** -0.169*** -0.170*** -0.169*** (-7.39) (-2.05) (-2.01) (-2.07) (-9.54) (-9.57) (-9.47) B/M 0.067*** 0.141*** 0.138*** 0.143*** 0.077*** 0.075*** 0.078*** -4.14 -7.18 -7.05 -7.28 -3.81 -3.68 -3.89 Age -0.055*** -0.081*** -0.080*** -0.083*** -0.016 -0.016 -0.016 (-4.19) (-4.72) (-4.69) (-4.83) (-0.97) (-1.01) (-1.01) Inb -0.067*** -0.049*** (-5.14) (-2.90) Inr -0.045*** -0.026 (-3.26) (-1.43) Constant 0.039*** -0.01 -0.01 -0.011 0.001 0.001 0.001 -3.35 (-0.72) (-0.71) (-0.73) -0.1 -0.1 -0.1 Observations 4,014 4,054 4,054 4,054 4,439 4,439 4,439 R-squared 0.483 0.203 0.204 0.202 0.092 0.093 0.091 F test 0 0 0 0 0 0 0 r2_a 0.482 0.202 0.202 0.2 0.0903 0.0913 0.0898 F 459.6 114.5 115.6 113.4 53.28 54.31 52.77 Note: *, ** and *** are significant at the level of 10%, 5% and 1% respectively Table 2. Regression Analysis for Hypothesis 1 4.3 Hypotheses Testing (1) Green Technology Innovation and Capital Cost To verify hypothesis 1, multiple linear regression analysis was carried out on models (1) - (7), and the results were shown in table 2. Green technology innovation has a negative impact on both the cost of capital and the cost of debt capital, and the result is significant at the 1% level, and the negative impact of green technology innovation on the cost of equity capital is significant at the 5% level, indicating that improving the level of green technology innovation can significantly reduce the cost of debt and equity capital and the total cost of capital. Hypothesis 1 is verified. (2) Green Technology Innovation and Carbon Performance (2) Green Technology Innovation and Carbon Performance To verify hypothesis 2, multiple linear regression analysis was carried out on models (8) - (10), and the results were shown in table 3. The total value of green technology innova- tion and disruptive green technology innovation have a significant positive impact on carbon performance at the level of 1%, and the progressive green technology innovation has a sig- nificant positive impact on carbon performance at the level of 10%, indicating that improving the level of green technology innovation can significantly improve the carbon performance of enterprises. Hypothesis 2 is verified. (3) Carbon Performance and Capital Cost 8 https://doi.org/10.1051/e3sconf/202340901016 E3S Web of Conferences 409, 01016 (2023) ICMSEM 2023 Table 3. Regression Analysis for Study Model8 Model9 Model10 Model11 Model12 Model13 Model14 Variable CP CP CP K Kd Ke K CP -0.119*** -0.122*** -0.072*** -0.117*** (-8.07) (-6.82) (-3.92) (-7.95) GTI 0.056*** -0.024** -2.85 (-2.10) Size 0.081*** 0.073*** 0.090*** -0.147*** -0.098*** -0.216*** -0.135*** -3.8 -3.47 -4.29 (-9.20) (-5.08) (-9.86) (-7.84) Grow 0.037** 0.037** 0.035** 0.047*** 0.001 0.092*** 0.045*** -2.13 -2.17 -2.07 -4.3 -0.06 -6.45 -4.17 Lev -0.106*** -0.103*** -0.108*** -0.729*** 0.291*** 0.071*** -0.731*** (-7.34) (-7.19) (-7.48) (-48.03) -14.52 -3.92 (-47.98) ROA -0.121*** -0.120*** -0.120*** -0.114*** -0.132*** -0.056*** -0.114*** (-6.70) (-6.67) (-6.71) (-6.49) (-5.90) (-2.73) (-6.51) Profit 0.599*** 0.600*** 0.600*** -0.039** 0.036 -0.121*** -0.042** -30.12 -30.16 -30.11 (-2.24) -1.61 (-5.56) (-2.41) B/M -0.108*** -0.105*** -0.110*** 0.055*** 0.129*** 0.063*** 0.053*** (-6.53) (-6.37) (-6.63) -3.37 -6.54 -3.12 -3.3 Age 0.078*** 0.078*** 0.080*** -0.045*** -0.071*** -0.01 -0.045*** -6.56 -6.53 -6.81 (-3.44) (-4.19) (-0.64) (-3.46) Inb 0.077*** -3.8 Inr 0.037* -1.74 Constant 0 0 0 0.039*** -0.01 0.001 0.039*** (-0.00) (-0.00) (-0.00) -3.37 (-0.71) -0.09 -3.38 Observations 4,480 4,480 4,480 4,014 4,054 4,439 4,014 R-squared 0.405 0.407 0.403 0.491 0.209 0.103 0.491 F test 0 0 0 0 0 0 0 r2_a 0.404 0.406 0.402 0.49 0.207 0.101 0.49 F 169 174 167.9 474.2 120.7 65.64 423.8 Note: *, ** and *** are significant at the level of 10%, 5% and 1% respectively Table 3. Regression Analysis for Study In order to verify hypothesis 2, multiple linear regression analysis was carried out on models (11) - (13), and the results were shown in table 3. (2) Green Technology Innovation and Carbon Performance The negative effects of carbon performance on total cost of capital, cost of debt capital and cost of equity capital are all significant at the level of 1%, indicating that enterprises’ active carbon emission reduction measures and improvement of carbon performance can significantly improve their carbon performance. Hypothesis 3 is verified. (4) Mediating Effect of Carbon Performance (4) Mediating Effect of Carbon Performance According to the first column of 2, the regression coefficient of capital cost to green technology innovation is 0.031, and it is significant at the level of 1%, indicating that the influence of green technology innovation on capital cost has an intermediary effect. It can be seen from the first and seventh columns of table 3 that the regression coefficient of carbon performance on green technology innovation is 0.031, the coefficient of capital cost on carbon performance is -0.117, and the coefficient of green technology innovation is -0.024, both of which are significant. Therefore, carbon performance plays a partial mediating effect. (5) Moderating Effect of Board Characteristics According to the regression result, the interaction term between green technology in- novation and board independence and the regression coefficient between green technology innovation and board gender diversity are both negative and significant. Therefore, board 9 E3S Web of Conferences 409, 01016 (2023) ICMSEM 2023 https://doi.org/10.1051/e3sconf/202340901016 independence and board gender diversity play a moderating role in the influence of green technology innovation on carbon performance. The regulating effect of board linkage is not significant. independence and board gender diversity play a moderating role in the influence of green technology innovation on carbon performance. The regulating effect of board linkage is not significant. 4.4 Robustness Test Some studies have pointed out that the influence of green patents on enterprises has a hys- teresis effect. Therefore, in the robustness test, the regression test is carried out on the green technology innovation variables with a lag of one stage, and the results have not changed substantially from the results above, which indicates that the conclusions of this study have certain robustness and reliability to a certain extent. 4.5 Discussion and Conclusion We integrate the latest research and theory on green innovation and cost of capital. The direct effect, mediating effect and the moderating effect of the hypothesis in our study are sup- ported. Green technology innovation influences the cost of debt capital and the cost of equity capital through the mediating role of carbon performance. Meanwhile, the characteristics of the board of directors play a moderating role in the relationship between green technology innovation and carbon performance. The researchers found that green technology innovation can reduce carbon emissions through product innovation, process innovation and end-treatment technology innovation. As a manifestation of corporate responsibility and moral level, carbon performance is widely concerned by investors. Companies with good carbon performance can gain the trust of investors and thus reduce the cost of capital. Consistent with the above views, our results also support the hypothesis that green technology innovation and carbon performance are negatively correlated with firms’ cost of capital. The results of our study are of practical significance to the development of green econ- omy. Firstly, the government should strengthen the incentives and penalties for carbon emis- sion reduction, link the effect of emission reduction to the economic costs of enterprises, and encourage heavy polluting enterprises to actively carry out green production. Secondly, en- terprises should actively respond to national policies, fulfill the social responsibility of carbon emission reduction, and enhance the level of green technology innovation. Finally, compa- nies should adjust the structure of the board of directors according to the actual situation and improve the effectiveness of the supervisory function of the board of directors. In the com- plex and changeable environment, companies should constantly improve their adaptability and strive to achieve coordinated development of environmental and economic benefits. This research was supported by Sichuan University Innovation Spark Project, grant number 2019hhs-17 and the Fundamental Research Funds for the Central Universities, grant number skbsh2020-23. This research was supported by Sichuan University Innovation Spark Project, grant number 2019hhs-17 and the Fundamental Research Funds for the Central Universities, grant number skbsh2020-23. ] F. Dong, J. Zhu, et al, Environmental Science and Pollution Research 29, 35780 (2022) [6] G. Zhou, L. Liu, S. Luo, Business Strategy and the Environment 31, 3371 (2022) g g 9] S. Khan, D.I. Godil, et al, Sustainable Development 30, 275 (2022) [10] S. Yao, Y. Pan, et al, Energy Economics 101, 105415 (2021) [7] R. Garzón-Jiménez, A. Zorio-Grima, Sustainability 13, 696 (2021) y ( ) ] C. Jiang, F.A. Zhang, C.A. Wu, Science of The Total Environment 764, 144248 (2021) [11] B.K. Agyei-Mensah, Corporate Governance International Journal of Business in Soci- ety 21, 569 (2021) [6] G. Zhou, L. Liu, S. Luo, Business Strategy and the Environment 31, 3371 (2022) [7] R. Garzón-Jiménez, A. Zorio-Grima, Sustainability 13, 696 (2021) [8] C. Jiang, F.A. Zhang, C.A. Wu, Science of The Total Environment 764, 144248 (2021) [9] S. Khan, D.I. Godil, et al, Sustainable Development 30, 275 (2022) [10] S. Yao, Y. Pan, et al, Energy Economics 101, 105415 (2021) [11] B.K. Agyei-Mensah, Corporate Governance International Journal of Business in Soci- ety 21, 569 (2021) References [1] M. Wang, L. Y, et al, Journal of Environmental Management 297, 113282 (2021) [2] M. Du, S. Chai, et al, Environmental Science and Pollution Research 29, 47661 (2022) [3] H. Beladi, J. Deng, M. Hu, International Review of Financial Analysis 76, 101785 (2021) [4] X. Xiang, C. Liu, M. Yang, International Review of Economics & Finance 78, 321 (2022) [5] F. Dong, J. Zhu, et al, Environmental Science and Pollution Research 29, 35780 (2022) 10 E3S Web of Conferences 409, 01016 (2023) ICMSEM 2023 https://doi.org/10.1051/e3sconf/202340901016 11 11
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Can Simulator Sickness Be Avoided? A Review on Temporal Aspects of Simulator Sickness
Frontiers in psychology
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Can Simulator Sickness Be Avoided? A Review on Temporal Aspects of Simulator Sickness Natalia Du˙zma ´nska1*, Paweł Strojny1,2 and Agnieszka Strojny1,2 1 R&D Unit, Nano Games sp. z o.o., Kraków, Poland, 2 Institute of Applied Psychology, Faculty of Management and Social Communication, Jagiellonian University, Kraków, Poland Simulator sickness is a syndrome similar to motion sickness, often experienced during simulator or another virtual reality (VR) exposure. Many theories have been developed or adapted from the motion sickness studies, in order to explain the existence of the syndrome. The simulator sickness can be measured using both subjective and objective methods. The most popular self-report method is the Simulator Sickness Questionnaire. Attempts have also been made to discover a physiological indicator of the described syndrome, but no definite conclusion has been reached on this issue. In the present paper, three temporal aspects of the simulator sickness are discussed: the temporal trajectory of the progression of simulator sickness, possibility of adapting VR users in advance and persistence of the symptoms after VR exposure. Evidence found in 39 articles is widely described. As for the first aspect, it is clear that in most cases severity of the simulator sickness symptoms increases with time of exposure, although it is impossible to develop a single, universal pattern for this effect. It has also been proved, that in some cases a threshold level or time point exists, after which the symptoms stop increasing or begin to decrease. The adaptation effect was proved in most of the reviewed studies and observed in different study designs – e.g., with a couple of VR exposures on separate days or on 1 day and with a single, prolonged VR exposure. As for the persistence of the simulator sickness symptoms after leaving the VR, on the whole the study results suggest that such an effect exists, but it varies strongly between individual studies – the symptoms may persist for a short period of time (10 min) or a relatively long one (even 4 h). Considering the conclusions reached in the paper, it is important to bear in mind that the virtual reality technology still evokes unpleasant sensations in its users and that these sensations should be cautiously controlled while developing new VR tools. Certainly, more research on this topic is necessary. Edited by: Alb Ri Edited by: Albert Rizzo, University of Southern California, United States Reviewed by: Eugene Nalivaiko, University of Newcastle, Australia Inmaculada Remolar Remolar, Universitat Jaume I, Spain Reviewed by: Eugene Nalivaiko, University of Newcastle, Australia Inmaculada Remolar Remolar, Universitat Jaume I, Spain *Correspondence: Natalia Du˙zma ´nska nduzmanska@nano-games.com Specialty section: This article was submitted to Human-Media Interaction, a section of the journal Frontiers in Psychology Received: 28 June 2018 Accepted: 16 October 2018 Published: 06 November 2018 Keywords: simulator sickness, temporal aspects, time, virtual reality, VR REVIEW published: 06 November 2018 doi: 10.3389/fpsyg.2018.02132 November 2018 | Volume 9 | Article 2132 Citation: Du˙zma ´nska N, Strojny P and Strojny A (2018) Can Simulator Sickness Be Avoided? A Review on Temporal Aspects of Simulator Sickness. Front. Psychol. 9:2132. doi: 10.3389/fpsyg.2018.02132 The simplest definition of virtual reality states that is “the use of computer-generated virtual environments and the associated hardware to provide the user with the illusion of physical presence within that environment” (Jayaram et al., 1997, p. 576). Virtual reality systems are widely used in the fields of scientific research (e.g., Anderson-Hanley et al., 2011), anxiety disorders therapy November 2018 | Volume 9 | Article 2132 Frontiers in Psychology | www.frontiersin.org 1 Can Simulator Sickness Be Avoided? Du˙zma ´nska et al. (e.g., Gerardi et al., 2010; Łukowska, 2011) or for professional training [e.g., in the army – (Braithwaite and Braithwaite, 1990); fire department – (Bliss et al., 1997); aviation – (Kennedy et al., 2000); medicine – (Bric et al., 2016)]. simulator training may lead to alleviation of the simulator sickness symptoms. A very detailed list of variables, which may have influence on simulator sickness occurrence and severity, may be found in the report by Kolasinski (1995). Many different virtual reality hardware systems and devices have been developed over the years and will be briefly described herein. Nowadays, the most popular are the head-mounted devices (HMDs), such as HTC Vive or Oculus Rift. The VR user wears a headset and holds two controllers which enable them to move and interact in a three-dimensional environment. Such devices are now being sold commercially. According to a recent Business Insider report (Hollander, 2018), there are four main VR headset types: stand-alone (which do not need any additional hardware to function), smartphone-powered, PC- powered and game console-powered. The report predicts that the stand-alone headsets will grow in popularity in the coming years. This could be of advantage for research employing the VR technology, as eliminating the wire which connects the headset to a PC or a console will make conducting experiments with multiple participants at the same time much easier. The main aims of this paper are to summarize the existing knowledge on simulator sickness with emphasis on its temporal aspects, to provide an overview of research on this topic and to propose further research directions and practical implications for virtual reality developers. Firstly, the most common theories which could serve as an explanation of the simulator sickness phenomenon will be discussed. Citation: Secondly, the methods of simulator sickness measurement, both subjective and objective, will be described in detail. Thirdly, three temporal aspects of simulator sickness will be discussed based on evidence found in empirical studies. And lastly, general conclusions drawn from the reviewed studies and practical implications for further research will be provided. Theories Potentially Explaining Simulator Sickness Another example of a VR system is a CAVE (cave automatic virtual environment). In such system, the environment is displayed and generated on several projectors, directed to the walls of the room and the user wears 3D glasses. Several theories have been developed to explain why individuals suffer from motion sickness. According to authors focused on virtual simulators, they may be also applicable in the field of simulator sickness during exposure to virtual reality (Brooks et al., 2010). The Sensory Conflict Theory, proposed by Reason and Brand (1975), explains motion and simulator sickness through a conflict that arises between different sensory systems; namely the signals from visual, vestibular and non-vestibular proprioceptors differ from one another and inevitably differ with expectations based on previous experience. According to the theory, only the conflict between present sensory information and that retained from immediate past elicits sickness. That is claimed on the basis of observation that continuous exposition to a stimulus results in eventual disappearance of symptoms (adaptation) even if the present conflict still exists (Reason, 1978). The vestibular system, which is responsible for perception and detection of direction, is crucial for occurrence of simulator and motion sickness symptoms (Reason and Brand, 1975). Different additional devices are used in order to provide the VR user with a realistic, multisensory experience. For example, treadmills are often used to simulate movement in the virtual environment (e.g., Jaeger and Mourant, 2001; Sinitski et al., 2018). For driving and flight simulators, a part of a plane cockpit or a body of a car may be used (e.g., Feenstra et al., 2011; Domeyer et al., 2013; Reinhard et al., 2017). Definition of Simulator Sickness Simulator sickness is a syndrome similar to motion sickness and can be experienced as a side effect during and after exposure to different virtual reality environments. Originally, the term “simulator sickness” was linked to effects induced by simulators consisting of a platform, often mobile, and with the visual stimuli generated by a computer, without head-tracking. The invention of HMDs led to developing another term, “cybersickness,” as such devices generate another issues, which may also lead to the unpleasant symptoms, such as the delay between actual head movements and the generated image. However, nowadays both of the terms are being used by researchers to describe the unpleasant symptoms evoked by the virtual reality technology (e.g., Sharples et al., 2008; Bruck and Watters, 2011; Serge and Moss, 2015; Lee et al., 2017). Reason (1978) proposed the Neural Mismatch Model which identifies the source of simulator sickness in discrepancies between expectations derived on a basis of present moves and contents kept in the neural store which, according to Reason (1978), contains information about typical combination of command signals (efference) and the integrated patterns of inputs from the orientation senses generated by them (reafference). That is the theoretical mechanism of adaptation to motion sickness observed for example by Reason and Brand (1975). To conclude, according to this model, sickness occurs when the received sensory information does not match one’s experiences based on past situations. The symptomatology and severity of the malaise depend on many variables – e.g., age, gender, stress, anxiety, one’s individual proneness to such ailment or the characteristics of the simulator itself (Kolasinski, 1995; Cobb et al., 1999; Mourant and Thattacherry, 2000; Jaeger and Mourant, 2001; Lin et al., 2002; Sharples et al., 2008; Brooks et al., 2010; Bruck and Watters, 2011; Classen et al., 2011; Moss and Muth, 2011; Zu˙zewicz et al., 2011; Biernacki and Dziuda, 2012; Dziuda et al., 2014; Helland et al., 2016; Lee et al., 2017). Lin et al. (2002) have also suggested that a relationship between one’s enjoyment experienced during Another theory, widely used to explain simulator and motion sickness, is the Postural Instability Theory. Riccio and Stoffregen (1991) have criticized the Sensory Conflict Theory – they state that sensory conflicts such as those described by Reason and Brand (1975) happen very often and are nothing unusual. Frontiers in Psychology | www.frontiersin.org Measurements of Simulator Sickness Self-Report Measures Simulator Sickness Questionnaire (SSQ) Originally published by Kennedy et al. (1993), the Simulator Sickness Questionnaire (SSQ) is a tool widely used for assessing the subjective severity of simulator sickness symptoms. In the pre-experiment part of the questionnaire, information about the current physical condition and participant’s experience with simulators is collected. The questionnaire consists of 16 items, derived from the Pensacola Motion Sickness Questionnaire (MSQ). Data collected during previous simulator studies using the MSQ was gathered and the items describing symptoms with less than 1% frequency of appearance or with no change in frequency between pre- and post-exposure were excluded from further analyses (12 of 28 items of MSQ). The severity of each symptom in the SSQ is measured on a four-point scale (0-3). The two aforementioned theories are most prevalent in the literature concerning simulator sickness. Other theoretical approaches to this phenomenon have been developed as well. The Eye Movement Theory developed by Ebenholtz (1992, 2001), uses the vagus nerve stimulation as an explanation for motion and simulator sickness. The mechanism is initiated by two specific eye movements (namely the optokinetic nystagmus and vestibular ocular response1) creating tension in the muscles of the eye, which stimulates the vagus nerve and leads to unpleasant symptoms such as difficulty concentrating, eye strain and headaches. According to the results of a factor analysis, the items of the SSQ can be grouped into three factors: nausea (e.g., sweating, difficulty concentrating, stomach awareness), oculomotor disturbance (e.g., headache, eyestrain, blurred vision) and disorientation (e.g., fullness head, dizziness with open and closed eyes, vertigo). The factors are not entirely independent – some of the items were included in more than one factor, e.g., the score on difficulty focusing is used to assess the severity of oculomotor disturbance and disorientation. In total, there are five such items. To calculate scores on each factor, all relevant items’ scores should be added (each factor consists of 7 items) and multiplying the obtained sum by a specific weight: for nausea by 9.54 (therefore the scores on this scale range from 0 to 200.34), for disorientation by 13.92 (scores ranging from 0 to 292.32) and for oculomotor disturbance by 7.58 (with scores ranging from 0 to 159.18). Bruck and Watters (2011) have also attempted to develop a comprehensive theory of cybersickness. Measurements of Simulator Sickness Self-Report Measures They suggest a following chain of causality: an increase in arousal leads to changes in respiration rate, which causes carbon dioxide levels in cerebral blood flow to decrease. These changes lead to the symptoms of simulator sickness: dizziness, fatigue, difficulty concentrating, fullness of head and anxiety. The authors propose dividing the simulator sickness symptoms into four factors: (1) general cybersickness factor, including most of the simulator sickness symptoms and indicated by feeling sick (generally) and nausea, (2) vision factor, including respiration, eyestrain and headache, (3) arousal factor, including respiration, blurred vision, vertigo, difficulty focusing and concentrating and stomach awareness, (4) fatigue factor, including the following symptoms: eyestrain, fullness of head, self-reported fatigue, dizziness and blurred vision. The overall score can be measured as well and it can serve as an indicator of total severity of the simulator sickness. It is calculated by adding scores on the 16 items and multiplying the achieved sum by 3.74, therefore the total score can range from 0 to 179.52. In addition to the quantitative data, qualitative information about peculiar sensations during the simulator experience and symptoms other that those listed in the main part of the questionnaire can be gathered (Kennedy et al., 1993; Biernacki et al., 2016). The Evolutionary Theory, proposed by Treisman (1977), originally explains the motion sickness, but its assumptions can be adapted to simulator conditions as well. Treisman (1977) suggests that people experience motion sickness, because – evolutionally – our species has not managed to adapt to new transportation modes yet. Therefore, the human body reacts to sensory conflicts with nausea – it acts as if poison had been ingested (Brooks et al., 2010). It can be assumed that similar reasons may stand behind the simulator sickness symptoms, as the human species had even less time to adapt to the virtual reality conditions. Although this theory does not propose any physiological mechanisms that may be responsible for Simulator Sickness Questionnaire has been used in numerous studies (e.g., Lampton et al., 1994; Mourant and Thattacherry, 2000; Jaeger and Mourant, 2001; Lin et al., 2002; Min et al., 2004; Sharples et al., 2008; Bruck and Watters, 2009a,b, 2011; Moss and Muth, 2011; Biernacki and Dziuda, 2014; Brunnström et al., 2017). 1Optokinetic nystagmus – an eye pursues a target object from one end of a visual field to the other. When the eye can pursue the object no further, it snaps back to the far side of the visual field where it begins to pursue again. Vestibular ocular response – responsible for keeping a target object on the fovea, the center of the retina where one’s vision is sharpest, when the head is turning. Definition of Simulator Sickness Furthermore, the difference (or lack of it) between what one’s November 2018 | Volume 9 | Article 2132 Frontiers in Psychology | www.frontiersin.org 2 Can Simulator Sickness Be Avoided? Du˙zma ´nska et al. experiencing simulator sickness, it can give a valuable insight on reasons why such ailment exists. senses experience and what an individual expects to feel is immeasurable. They have proposed that the symptoms of motion or simulator sickness may be experienced when one has been exposed to long-lasting postural instability and has not yet learned how to adjust to this situation and maintain proper balance. The most vivid example of such phenomenon is the feeling of instability one experiences when traveling by ship. A similar situation occurs during rollercoaster rides as well (Riccio and Stoffregen, 1991). Physiological Measures Although a conclusion has not yet been reached on which specific physiological parameters are the best indicators of simulator sickness, some researchers (e.g., Min et al., 2004; Bruck and Watters, 2011; Zu˙zewicz et al., 2011) have tested various physiological variables and some of them appear promising for evaluating simulator sickness without relying on self-report measures or as a supportive method for questionnaires such as SSQ. It has been noted (Min et al., 2004) that during driving (and most of the studies concerning simulator sickness were conducted with various driving simulators) the increase of autonomic nervous system activation may relate to tension, which then causes the heart rate and skin conductance to increase and skin temperature to decrease. Moreover, the physiological measures may be useful, as it has been proved that the subjective evaluation of simulator sickness (e.g., with the SSQ questionnaire) is slightly delayed when compared to the physiological indicators (Min et al., 2004). Therefore, establishing the best physiological indicators of simulator sickness could shed more light on the exact triggering time of the syndrome and therefore allow a more accurate description of the temporal characteristics of simulator sickness. Other autonomic variables. In the course of research, some other measures of the autonomic nervous system activity have been tested. This paragraph will provide a brief overview of them. Kim et al. (2005) have observed an interesting pattern of the gastric tachyarrhythmia changes – in increased significantly in the first 4 min of virtual reality exposure and then continued to increase until the final 4 min of a 9.5 min trial. The eyeblink rate did also change in the study by Kim et al. (2005) – it decreased in the first minute of the exposure (when compared to the baseline rate), but then increased and in the middle of the trial it was significantly higher than the baseline level. Another interesting measure is the skin temperature – as observed by Kim et al. (2005), when measured at the fingertip, the skin temperature decreased in the middle of the trial and remained significantly lower than the baseline level even after leaving the VR environment. Such decrease in skin temperature was also observed by Chung et al. (2007) and Brooks et al. (2010). Furthermore, according to the results obtained by Kim et al. (2005), the respiratory sinus arrhythmia (a variation in heart rate occurring during breath cycle) increases during VR exposure. Heart rate Bruck and Watters (2011) propose that the heart rate may serve as an indicator of simulator sickness, as it had been previously proved that it correlates with such syndrome. In experiments conducted by Cobb et al. (1999) heat rate tended to accelerate during the simulator task and returned to a resting rate in approximately 30 min after completing the task. Furthermore, the heart rate of the participants who reported more severe simulator sickness symptoms was also higher than the heart rate of the individuals who did not experience such unpleasant sensations. Additionally, the heart rate of the participants who showed symptoms of adapting to the VR (virtual reality) conditions during several exposures decreased over the three sessions. Changes in heart rate were observed in a couple of studies. Dahlman et al. (2008, 2009) have noted an increase in heart rate during a VR exposure. In a study by Gavgani et al. (2016) the subjects participated in three roller coaster simulator rides, which took place on separate days. For the first 2 days, an initial tachycardia and tachypnoea that gradually lowered during the ride was observed. No such patterns were discovered on the third day. Physiological Measures As no unambiguous physiological indicators of simulator sickness have been discovered, some examples of use of physiological indicators for measuring this syndrome will be described in this paragraph. Other self-report measures Other self-report measures It should be noted that in some studies self-report methods of measurement different from the Simulator Sickness Questionnaire had been used – Brooks et al. (2010) report having used the Motion Sickness Assessment Questionnaire, Mali´nska et al. (2014) used a self-developed, concise questionnaire and Helland et al. (2016) measured subjective severity of simulator sickness symptoms simply by asking – “To what extent did you experience simulator sickness during the driving test?”. Several other authors used other short self-report measures (e.g., McCauley et al., 1990; Helland et al., 2016; Reinhard et al., 2017). As these methods are either a questionnaire originally created for measuring a different ailment or have not been psychometrically tested, they will not be described more widely herein. Measurements of Simulator Sickness Self-Report Measures The brevity and simplicity of the questionnaire are its assets, as in many study designs it is being used at least twice to assess the changes in occurrence and severity of simulator sickness’ symptoms. In most cases SSQ is used as a paper-and- pencil test, but it can also be conducted orally – as in Min et al. (2004) study, where the items of the questionnaire were read to the participants by the experimenter (according to the authors of November 2018 | Volume 9 | Article 2132 Frontiers in Psychology | www.frontiersin.org 3 Can Simulator Sickness Be Avoided? Du˙zma ´nska et al. the study, conducting the SSQ orally requires only circa 30–40 s) or in the study by Moss and Muth (2011), where a cassette was pre-recorded and then played back to the participants. Kim et al. (2005) – in their study a decrease in the respiration rate (when compared to baseline levels) was observed. What is more, a positive correlation was observed between respiration rate and the Simulator Sickness Questionnaire scores (for all of the subscales and the total score, with the r values oscillating between 0.342 for nausea and 0.392 for the total score). Frontiers in Psychology | www.frontiersin.org Autonomic nervous system Respiration (breaths per minute). According to one of the theories of simulator sickness (or “cybersickness,” as referred to by the authors; Bruck and Watters, 2011), the changes in respiration rate are crucial to evoking the unpleasant symptoms, especially when the person subjected to a virtual reality environment has no control. Respiration loads two factors in the theory of cybersickness developed by Bruck and Watters (2011): Vision and Arousal. They even propose that hyperventilation may be the cause of arousal experienced by individuals exposed to high levels of movement in a virtual reality. Empirical evidence of changes in respiration rate during VR exposure were achieved by What is interesting about the above mentioned measures is the fact that for all of them, except for skin temperature, positive correlations with the subjective measurement of the simulator sickness (SSQ) were observed (Kim et al., 2005), with the Pearson r values ranging between 0.265 (eyeblink rate and oculomotor disturbance scale) and 0.359 (gastric tachyarrhythmia and nausea scale). Furthermore, in a study by Gavgani et al. (2016), a rapid increase in finger skin conductance levels was observed during Frontiers in Psychology | www.frontiersin.org November 2018 | Volume 9 | Article 2132 4 Can Simulator Sickness Be Avoided? Du˙zma ´nska et al. the first minute of the VR exposure – the subjects experienced increased sweating in the finger; this trend was present until the end of the experimental trial. However, what is the most interesting, in the cited study phasic SCL activity in the forehead was observed during the experimental trial (compared to none during baseline measurement). This activity – and only this of all of the measured physiological responses – was proven to be associated with the experience of nausea. Cobb et al. (1999) report using a more complex set of postural stability tests: in their research program, the following methods of measurement were used: measuring the extent to which a static posture could be held, measuring the extent of hip sway over a 30 s period, walking on the floor and navigating over an uneven path with open eyes. Additionally, the authors administered two scales: task difficulty scale and subjective postural stability scale (Postural Stability Questionnaire – PSQ; Hamilton et al., 1989) after completing all the tasks. associated with the experience of nausea. Central nervous system As a measure of the central nervous system activation, EEG has been used in some of the studies (Min et al., 2004; Chung et al., 2007). According to the results obtained by Min et al. (2004), there are significant differences in brainwaves patterns between rest and driving in a driving simulator. Such results have been obtained both for the frontal (Fz) and parietal lobe (Cz), giving similar patterns. After 5 min of simulator exposure, the δ/total increased and α/total, ß/total and θ/total decreased significantly in 5–35 min of simulator exposure. Furthermore, the δ/total at Fz correlates positively, and both θ/total and ß/total at Fz and Cz negatively, with the total SSQ score. The correlation with the SSQ score was the strongest for the θ/total parameter (r = −0.842 at Fz and r = −0.93 at Cz), therefore the authors of the study (Min et al., 2004) propose that it could serve as the most effective physiological indicator of simulator sickness occurrence. This proposal was also supported by Chung et al. (2007). Temporal Aspects of Simulator Sickness Temporal Aspects of Simulator Sickness Questions regarding the temporal characteristics of the virtual reality experience which influence simulator sickness seem to recur in many papers (e.g., Kennedy et al., 2000; Moss and Muth, 2011; Domeyer et al., 2013). Although no unambiguous answers have yet been provided, some useful and promising leads can be found in literature and will be discussed herein. Since the main goal of the present work was to review research on simulator sickness from the temporal perspective, we decided to focus on research regarding one (or more) of the three issues described below. As Kennedy et al. (2000) have observed, there are two main phenomena regarding the temporal aspect of simulator sickness: that the severity of simulator sickness increases with the increase of exposure duration during a single session, and that subjecting a person to several repeated simulator exposures may result in adaptation to the simulator conditions and thus in decrease of simulator sickness symptoms severity. The aforementioned aspects will be discussed in the present paper, as they seem to be crucial as far as virtual reality development is concerned. Furthermore, according to some research (e.g., Moss and Muth, 2011; Biernacki and Dziuda, 2014; Mali´nska et al., 2014), the simulator sickness symptoms appear to persist for some time after the simulator exposure – this aspect will be discussed below as well. Search Strategy A search of literature was performed in three electronic databases (Web of Science ‘all databases,’ PsychArticles, Scopus) with no publication date restriction. Since temporal aspects of simulator sickness rarely are the main focus of studies, we decided to retrieve a wide range of articles using the broadest term “simulator sickness” and assuming intensive article selection in subsequent stages. Thousand two hundred records were obtained. The search was conducted on 19th April 2018. Behavioral Measures – Postural Stability Tests Behavioral Measures – Postural Stability Tests When relying on the Postural Instability Theory (Riccio and Stoffregen, 1991), one could use a postural stability test in order to assess the lack of postural stability as a specific manifestation of simulator sickness. Mourant and Thattacherry (2000) report using such test in their study. It is a simple and brief method – the person is asked to stand on the leg of their choice for 30 s in two separate trials. The time of standing without putting the other leg down is recorded and can be compared to the results of the same test after experimental manipulation or can serve as an independent measure. Although this method does not give a broad insight into simulator sickness symptoms, it can be useful when assessing changes in postural stability dependent on simulator exposure. Autonomic nervous system The authors (Gavgani et al., 2016) give an interesting interpretation of their findings, which may shed new light on the physiological components of the simulator sickness experience. Some of the physiological symptoms (initial tachycardia, tachypnoea, finger sweating) were present at the initial phase of the VR exposure, in the time during which no self-reported nausea was present. This conclusion is supported by the fact that the above mentioned effects (except for finger sweating) became non-significant on the last, third exposure. The authors conclude that these symptoms may be evoked by emotions and arousal connected with the novelty of the VR experience. The forehead sweating, however, is related to the development of nausea. These results correspond with Treisman’s (1977) evolutionary theory of motion sickness – reducing the body temperature by increasing sweating serves as a survival strategy during intoxication. Study Selection Authors conducted a title and abstract screening, in order to exclude obviously irrelevant articles. Following keywords were used: time, temporal, durat∗, adapt∗, persist∗. The articles which titles and abstracts suggested an irrelevant area of research were excluded on this basis (1086 records). In the second stage of the screening process, full texts were retrieved and duplicated records removed (34 records). For 10 records full texts were unavailable November 2018 | Volume 9 | Article 2132 Frontiers in Psychology | www.frontiersin.org 5 Can Simulator Sickness Be Avoided? Du˙zma ´nska et al. and thus these records were excluded from the database as well. 70 articles were retrieved and evaluated in full text using the following criteria: statistical significance of these effects. Nevertheless, these results are interesting and worth being taken into consideration when planning further experiments on extended VR exposure. Kennedy et al. (2000) examined SSQ data from a military pilots’ flight simulator training database and categorized them by exposure duration into four categories (0–1, 1–2, 2–3 h, 3 or more hours). An analysis of variance revealed that the mean SSQ scores increase gradually when exposure duration increases. This trend proved to be statistically significant. No information on statistical significance of differences between each of the categories was given and it also should be noted that the analyzed data concerned many different simulator environments. It was also a between-subject design, therefore no conclusions about individual temporal patterns of simulator sickness severity can be made. (1) published in full in English or Polish, (2) based on empirical data, (3) temporal aspects of simulator sickness are investigated, (4) at least three time points for measurement of simulator sickness (applicable for studies regarding the temporal trajectory of the progression of simulator sickness), (5) the study subjects were human, (6) not investigating an intervention on simulator sickness, (7) testing simulators or other forms of virtual reality (not 3D movies or desktop applications), (8) measuring simulator sickness using psychometric methods (questionnaires). Min et al. (2004) have tested various measures of simulator sickness severity. In their study, both physiological and self-report methods were used – the Simulator Sickness Questionnaire was used for assessing the subjective severity of the syndrome. Only the results of the psychometric measurement will be reported herein. The Temporal Trajectory of the Progression of Simulator Sickness Studies on simulator sickness have been conducted since 1990s, using a wide array of virtual reality devices. Therefore, it is important to emphasize the fact that direct comparisons between studies using different hardware should be treated with extreme caution. Some trends may be observed, but it should be always borne in mind that for different devices and scenarios the temporal patterns of simulator sickness may vary significantly. Moreover, as some of the cited studies have been conducted almost 20 years ago, caution should be taken while making conclusions. However, the insight provided by the researchers appears to be valuable – while the technological development might have solved some of the problems, the methodology and qualitative conclusions are worth knowing. Moss and Muth (2011) tested several characteristics of HMDs as possible factors influencing simulator sickness severity, as well as the effect of a prolonged exposure. Only the latter of these effects will be reported herein. The participants’ task was to locate several objects in the virtual environment (a virtual laboratory), according to verbally given instructions, using only head movements. Each participant completed two practice sessions and five 2-min trials with 1-min breaks between them. A number of Simulator Sickness Questionnaire results were collected: before the experiment, after a practice session, after each trial, 5 and 10 min after the experiment. It was noted that the severity of simulator sickness symptoms increased with time – a significant effect of duration of the VR exposure was revealed. The most severe symptoms were noted after the last trial. In one of the studies conducted by Cobb et al. (1999), four subjects were immersed in a virtual reality environment for 1– 2 h. Simulator sickness severity was measured with the Simulator Sickness Questionnaire. The participants were asked to remain in the virtual reality for up to 2 h. All participants reported the severity of symptoms increasing up to 1 h of exposure. Two of the participants withdrew after an hour when the simulator sickness symptoms experienced by them were too severe (mean scores for nausea: M = 67, oculomotor disturbance: M = 57 and disorientation: M = 82). The remaining two participants completed the 2-h immersion and reported that after 75 min the severity of symptoms decreased greatly. Study Selection After baseline signal measurement and pre-experiment SSQ administration, the participants of the study drove a car simulator for 60 min, during which physiological measurements were conducted and the SSQ was completed orally after every 5 min of the simulator exposure, as well as after completing the whole trial. The authors of the study report that all of the participants showed symptoms of nausea, disorientation (after 10 min of simulator exposure) and oculomotor disturbance (after 25 min). The first significant difference between the baseline SSQ score and trial score appeared 10 min after beginning of the trial. The obtained results confirm the hypothesis that the severity of simulator sickness increases with time. After this process, 30 articles were retrieved. The authors decided to add 5 articles on the basis of hand search and previous knowledge. The final database consisted of a total of 35 articles (41 studies). A flow chart describing the search and screening process is presented in Supplementary Figure S1. Frontiers in Psychology | www.frontiersin.org (1) a gamepad, ( ) d The Temporal Trajectory of the Progression of Simulator Sickness This suggests that although the simulator sickness symptoms severity increases with time, for some individuals it may be possible to adapt to the VR environment during a single exposure. Unfortunately, the sample in the study was too small to provide information on The type of walking interaction was the main topic explored by Lee et al. (2017), but their results also provide information about the temporal characteristics of simulator sickness. In their experimental design three types of walking control were included: (2) sensors detecting hand movements and thus using specific hand gestures for walking control, (3) a walk-in-place marching simulator with sensors and portable walking simulators attached to legs. November 2018 | Volume 9 | Article 2132 6 Can Simulator Sickness Be Avoided? Du˙zma ´nska et al. thoroughly analyze the pattern of the symptoms during the whole exposure. All of the participants of the study were exposed to three different VR environments (a cartoon town, a realistic nature environment and a low poly2 landscape in a three-step walking interaction: they either experienced them in the order of: gamepad, hand interface, walking simulator or in the reverse order – each of the participants completed nine VR experiences in total. The following variables were tested in the study: immersion, presence and simulator sickness (measured with the Simulator Sickness Questionnaire). The authors reported that the simulator sickness symptoms became more severe with time, although on the whole they were of moderate severity. An experiment conducted by Moss et al. (2008) consisted of a short practice and five 2-min experimental trials. It was confirmed that the simulator sickness (measured with the SSQ) severity increases with time – it was more severe after the last (5th) trial than: before the practice, after the practice, after the 1st, 2nd, and 3rd trials. As no significant differences were discovered between the 4th and 5th trial, it may be hypothesized that after circa 9 min of exposure the simulator sickness has reached its peak severity and would not become more unpleasant if the exposure duration was even longer. In a similar study (Moss et al., 2011), a phenomenon of the simulator sickness severity (measured with the SSQ) increase with the increased VR exposure duration was confirmed. The Temporal Trajectory of the Progression of Simulator Sickness In the study by Classen and Owens (2010), simulator sickness severity was measured at three time points: before VR exposure, after a 5-min acclimation exposure and after a 20-min trial. The obtained results indicated that the simulator sickness severity increased between the baseline score and both after-acclimation and post-exposure, but no significant differences were discovered between the after-acclimation and post-exposure scores. Therefore, one may presume, that the peak simulator sickness severity in this study was reached very early. However, no data was gathered during the 20-min exposure, so it is possible that some differences might have been discovered if more systematic simulator sickness measurements had been conducted. A similar procedure was conducted by Sinitski et al. (2018) – they measured the simulator sickness severity (with the SSQ) before the exposure, after an acclimation period (which lasted for 15 min) and after a 45-min trial. In this study, however, only a small increase in the disorientation scale was observed after the acclimation period and these symptoms decreased by the end of the session. Again, the period between the second and the third measurement was quite long, and therefore it is impossible to A systematic increase of simulator sickness severity (measured with the SSQ) with time was confirmed by Chung et al. (2007), Park et al. (2008), and Choi et al. (2009) during a 60-min trial and Aldaba et al. (2017), who measured simulator sickness severity with the SSQ, and by Reinhard et al. (2017), who used the Fast Motion Sickness Scale (FMS – a single-item scale, the scores on which range from 0 to 20). An increase of simulator sickness symptoms severity was also observed by McCauley et al. (1990), when it was rated on a 7-point scale (“normal, symptom-free” – “severe discomfort, I am unable to continue”) – it increased between measurement time points: before the exposure, in the middle of the 10-min task and after the whole 10-min task. There were 4 such trials and an increase in severity of the symptoms was observed for all of them. A brief summary of all reviewed studies is provided in the Supplementary Table S1. Several conclusions can be drawn from the perspective of the temporal trajectory of the progression of simulator sickness on the basis of the studies retrieved. The Temporal Trajectory of the Progression of Simulator Sickness Serge and Moss (2015) measured simulator sickness severity with the Revised Simulator Sickness Questionnaire and proved that it does increase with time when measured before VR exposure and after 8 and 16 min of exposure. Singer et al. (1998) report as well that the simulator sickness severity increases with time during a VR exposure, although the difference between a “Mid-Experiment” and “Post- Experiment” scores was not significant, suggesting an appearance of a threshold simulator sickness level. The authors, however, did not give information on how long the trials were, and therefore any conclusions drawn from this study should be treated with caution. Feenstra et al. (2011) have discovered a slightly different phenomenon than the ones above described – in their study, the differences in simulator sickness severity began to become statistically significant after the participants spent 10 min in the VR and then it increased until the end of the 20-min trial. The above-mentioned study results support the hypothesis, that the severity of simulator sickness does increase with time during a single exposure, to various extents, which may differ depending on many variables (e.g., simulator type and its characteristics, length of the whole exposure, individual characteristics of the participants, etc.). Such results are confirmed in many other studies, which will be briefly summarized herein. Lo and So (2001) have confirmed that the nausea severity (measured by one question with answers ranging from 0 – “no symptom” to 6 – “moderate nausea, want to stop”) increases linearly with time during a 20-min exposure. Furthermore, the increase was significant in all of the comparisons, except for the one between the 15th and 20th minute of the trial. A similar study was conducted (So et al., 2001), and during a 30-min exposure the nausea ratings (measured in the same way as above) increased as well, but the differences were significant only in the 5th and 10th minute. Jarchow and Young (2007) have also measured the simulator sickness severity by asking just a single question (with a scale from 0 – “normal” to 20 – “about to vomit”). The subjects were tested on two consecutive days, as the main aim of the study was to assess the adaptation effect. It was however, discovered as well that within a single session the severity of symptoms increases, but this effect was observed in only one of the experimental conditions. 2Consisting of a small number of polygons. November 2018 | Volume 9 | Article 2132 The Temporal Trajectory of the Progression of Simulator Sickness Firstly, there is empirical evidence to expect that severity of simulator sickness grows along time of exposure, as several studies using various approaches confirmed this hypothesis. In light of the reviewed research, this trend seems to be stable regardless of the technological progress in the field of VR presentation – the oldest studies (McCauley et al., 1990) and the most recent one (Sinitski et al., 2018) lead to the same conclusion. Even using between-subject comparisons leads – in most of the cases – to the conclusion that the severity of simulator sickness symptoms is greater when the exposure November 2018 | Volume 9 | Article 2132 Frontiers in Psychology | www.frontiersin.org 7 Can Simulator Sickness Be Avoided? Du˙zma ´nska et al. duration is longer (e.g., Kennedy et al., 2000). However, it is important to note that several moderators, which are not the main focus of this paper, may play a role here – for example, a simulator control method. Secondly, it is difficult to establish a universal rule regarding the maximum time individuals can spend in VR on the basis of the analyzed study results. On the other hand, in most of the studies the simulator sickness symptoms were experienced by all of the participants, not only the ones who reported some kind of tendency to feel sick. identical virtual environment, but also by similar experiences, such as video gaming. It has been shown that individuals with more gaming experience and more self-reported “computer skills” experienced less unpleasant symptoms during a VR session (Häkkinen et al., 2006a). However, there are also studies which do not support this claim (e.g., Häkkinen et al., 2002, 2006b), therefore this issue needs further testing. Some adaptation effects were observed by Lampton et al. (2000). In their study, five separate VR immersions were conducted (trainings 1 and 2 and missions 1, 2, and 3). The SSQ was administered before and after each immersion. The pre-post immersion score difference was significant for the first training and the second and third mission, and not significant for the second training and first mission. Therefore, it can be concluded, that after the first training the participants achieved some adaptation, but its effect wore offwith time. Similarly, in the study by Domeyer et al. 3“In the SRS, participants were asked to raise their right hands above their heads and grasp their right earlobe with their left hand, bend at the waist, and spin in a clockwise direction under self-propelled condition. The participants spun 10 times in 30 s (20 RPMs) and this constituted a trial” (Smither et al., 2008, pp. 330–331). The Temporal Trajectory of the Progression of Simulator Sickness (2013), the adaptation effect was obtained during a series of VR exposures conducted on 1 day, and in this study the subjects did adapt to the simulator conditions (the effect was visible on the total Revised Simulator Sickness Questionnaire score). Such effects may occur even during a relatively short exposure, lasting 45 min in total (Sinitski et al., 2018). In the quoted study the participants experienced an increase in disorientation symptoms (measured with the SSQ) at first, but it decreased by the end of VR exposure. However, such effect was not confirmed for the remaining SSQ subscales and for the total score. Additionally, it should be stressed that all of the VR immersions of the two studies mentioned above took place during a single day, which is quite unusual for studies exploring adaptation effects – usually each of the immersions is conducted on a separate day. Moreover, in some of the studies it was observed that the simulator sickness severity increases with time, but after reaching a certain level or after a certain amount of time it either begins to decrease (Cobb et al., 1999; Sinitski et al., 2018) or remains on the same level (Singer et al., 1998; Lo and So, 2001; So et al., 2001; Moss et al., 2008; Classen and Owens, 2010). It can lead to a conclusion, that during a single VR exposure it is possible for some people to achieve simulator sickness adaptation (or, for some simulator types, to evoke the adaptation effect). However, it should be further explored whether this effect transfers to subsequent VR sessions. On the other hand, it has also been proved that in some cases the simulator sickness symptoms begin to show after some time spent in VR and that this time threshold may be different for various simulator sickness symptoms (Min et al., 2004; Feenstra et al., 2011). Although this type of evidence is less prevalent than the one described above, it is also worth being taken into consideration. If the symptoms start being unpleasant after some time, a single VR session should be short enough to prevent these symptoms from occurring. Keeping in mind several moderators which may vary between software (e.g., way of control, setting, graphics quality), another strategy of testing temporal tolerance may be reasonable, viz. testing of certain VR software using precisely selected methods. The Temporal Trajectory of the Progression of Simulator Sickness In order to make it possible, various methods need to be integrated, and standardized methodology needs to be developed. In the study program developed by Cobb et al. (1999), 12 individuals participated in three consecutive virtual reality sessions, each of which lasted 20 min, with a 1-week break between the sessions. The simulator sickness symptoms severity (measured with the Simulator Sickness Questionnaire) decreased after each consecutive VR exposure, especially strongly for the disorientation symptoms, which is consistent with the results obtained by Sinitski et al. (2018). A similar effect of adaptation was observed by Braithwaite and Braithwaite (1990) and Bailenson and Yee (2006) – in their studies, the simulator sickness symptoms (measured with the SSQ) decreased in severity with time. Frontiers in Psychology | www.frontiersin.org Possibility of Adapting VR Users in Advance (2000) analyzed data collected from 53 individuals – military pilots, who participated in seven consecutive helicopter simulator trainings. A repeated-measures analysis of variance indicated that a monotonic decrease in simulator sickness severity (measured with the SSQ) as a function of flight number can be observed. Furthermore, for some subjects a floor effect was observed – they reached a total adaptation and the SSQ 0 score at some point, which did not increase in further trials. This effect is responsible for the deceleration in the decline of simulator sickness severity with time. The authors propose that, according to their results, short, repeated simulator exposures may be used in order to achieve adaptation to the VR environment and to prevent simulator sickness. Moreover, they further conclude that the decrease in simulator sickness severity after several trials exceeds the increase in severity with a single longer exposure duration. Helland et al. (2016) conducted an experiment on a driving simulator, during which the effects of simulator sickness, blood alcohol concentration and repeated simulator exposures on driving performance were studied. Herein, only the results concerning the relationship between repeated simulator exposures and simulator sickness severity will be discussed. A driving simulator consisting of the body of a car and three screens were used. The study included three 60-min long driving tests in the simulator (with at least 2-day breaks between the trials). After every trial each of the 20 participants assessed the simulator sickness severity by rating it on a scale from 0 to 10 – they were asked – “To what extent did you experience simulator sickness during the driving test?”. It is worth noting that the mean simulator sickness score was very low in this study (M = 2.5), which might have had an impact on the results. For the participants, who did not interrupt any of the sessions (N = 13), the mean simulator sickness severity score was 3.4 for the first, 1.8 for the second and 1.5 for the third session. Although the simulator sickness severity appears to decrease with consecutive sessions, the relationship was not statistically significant. It could be hypothesized that had the authors used a more precise method for assessing the simulator sickness severity, the results could have been different. Possibility of Adapting VR Users in Advance With the concise, one-question simulator sickness severity measurement, the data given in the study report do not fully support the hypothesis that simulator users adapt to the virtual reality conditions. Brooks et al. (2010) conducted two studies – an exploratory and a confirmatory one. In the exploratory study (a combination of results of three independent studies), the participants were immersed in a driving simulator. After a training session, four 5-min trials using slightly different conditions (e.g., a curvy road instead of a straight one) were conducted. Between the sessions, 2-min rest periods took place. Before and after each trial, the participants completed the Motion Sickness Assessment Questionnaire, the score of which served as an indicator of simulator sickness severity. In the confirmatory study the main difference was that the participants completed three 30-min experimental trials in the same simulator. The authors report that for some participants an adaptation effect was showed – their symptoms’ severity increased at first, but then decreased as they became accustomed to the simulator experience. No statistical parameters were provided to describe this tendency, but it still appears to be a promising information. y Another study providing evidence supporting the hypothesis, that simulator sickness adaptation is possible, was conducted by Reinhard et al. (2017). Twenty eight participants took part in the experiment, it had two parts, separated by 7–14 days of a break. On the first day, six 20-min drives in a simulator took place and on the second day there were four of them. To assess the simulator sickness severity, two scales were used: the FMS and the SSQ. The authors report an interesting pattern of results. During both sessions, the severity of symptoms did increase, but that increase was less visible during the second session. Thus, an adaptation effect was proved, but it was not a complete disappearance of symptoms. It was stressed in the paper, that the first VR immersion should be treated with extreme caution – the subjects should be monitored for unpleasant symptoms, the rests between trials should be longer and the trials themselves shorter than usual. For a summary of studies reviewed in this aspect, see the Supplementary Table S2. pp p g In a study by Newman et al. (2013) the subjects took part in 6 VR immersions, five of which happened on consecutive days and the last – 22 days after the first immersion. Possibility of Adapting VR Users in Advance As Nader and Kruszewski (2013) suggest, simulator sickness can be avoided when the virtual reality users are allowed a sufficient amount of time to adapt to the simulator conditions. They propose that such adaptation sessions may last for a number of days and involve an increase in time spent in the simulator during a single training, as well as an increased difficulty of the task. This proposal appears to be congruent with the assumptions of some of the theories. For example, according to the Neural Mismatch Model (Reason, 1978), unpleasant symptoms occur when the present sensory information is inconsistent with past experiences of the individual. Gaining such experience in the specific virtual reality environment might prevent the aforementioned conflict. Similarly, when one is allowed to immerse in virtual reality several times, one can learn how to maintain balance in such an environment – adaptation appears to be possible in the paradigm of the Postural Instability Theory (Riccio and Stoffregen, 1991) as well. It should also be emphasized that adaptation to simulator sickness in VR may be achieved not only by exposure to an An interesting form of adaptation training was proposed by Smither et al. (2008). They tested the ability of a self-propelled rotation stimulation (SRS)3 to provide adaptation to simulator sickness. Ten subjects took part in five SRS trials on separate days and on the last day were exposed to a VR, and 10 other subjects took part only in the latter part of the experiment, providing a control group. The control group experienced significantly more severe dizziness symptoms and higher total, disorientation and oculomotor disturbance SSQ scores. These results show that adaptation can be achieved without immersing in the virtual November 2018 | Volume 9 | Article 2132 Frontiers in Psychology | www.frontiersin.org Frontiers in Psychology | www.frontiersin.org 8 Can Simulator Sickness Be Avoided? Du˙zma ´nska et al. reality, but some form of pre-immersion training is needed to prevent the unpleasant symptoms, as the participants from the control group, who did not have a chance to adapt in any form, suffered from the simulator sickness. simulator sickness severity should be chosen cautiously, as the effects may slightly differ when using different methods. Probably the best option would be to use at least two reliable methods of comparison as it was done by Newman et al. (2013). Kennedy et al. Frontiers in Psychology | www.frontiersin.org Persistence of the Simulator Sickness Symptoms After VR Exposure Tanaka and Takagi (2004) discovered, that not only the simulator sickness symptoms persist for some time after VR exposure, but also the length of the persistence is dependent on the initial symptom severity. For the participants who suffered from severe symptoms (total SSQ score of more than 60), the recovery time was longer than 30 min. On the other hand, the subjects, who experienced only slight symptoms (total SSQ score of 25 or less) needed no longer that 5 min to recover from the simulator sickness symptoms. Biernacki and Dziuda (2014) have studied simulator sickness symptoms on a group of professional truck drivers, who participated in three 30-min truck simulator drives – the first one on a fixed-base platform with poor visibility (created by a simulated fog) and twice with good visibility: on a fixed base and on a mobile platform. The simulator consisted of a truck cabin and a cylinder screen, on which all visual stimuli were displayed. The simulator sickness was measured with the Simulator Sickness Questionnaire. The questionnaire was completed five times for each exposure: before each trial, 2 and 30 min after all of the trials, in the evening of the same day and next day, in the morning. The level of nausea, disorientation and oculomotor disturbance, as well as the total severity of simulator sickness symptoms proved to be dependent on the measurement time point. The level of nausea was higher 2 min than 30 min after exposure. The time profile for oculomotor disturbance, disorientation and the total SSQ score turned out to be similar: the scores 2 min after exposure were significantly higher than 30 min after exposure and the baseline scores. The symptoms of simulator sickness seem to retreat after leaving the virtual reality environment, but only for the nausea factor the simulator sickness severity 30 min post exposure did not differ significantly from the baseline score. Half an hour appears not to be sufficient time for the symptoms to disappear completely. In another paper (Dziuda et al., 2014) describing the results of this study, the authors state, that the severity of nausea measured 2 and 30 min post exposure and in the evening of the same day was significantly higher than in the morning of the next day. In the study by Bos et al. Persistence of the Simulator Sickness Symptoms After VR Exposure (2005) it was also confirmed that the simulator sickness symptoms tend to persist for some time after VR exposure, but they return to baseline [a score of 0 on the Misery Scale (MISC); the maximum score on this scale is 10] in an hour following the end of the VR exposure for most of the participants. Only 4 of 24 subjects did not fully recover within 2 h post exposure, with the maximum MISC score of 3. These conclusions are supported by the results obtained by Keshavarz et al. (2018). In their study simulator sickness was measured using the FMS and 36 of 121 participants were forced to drop out before the end of the experimental task. The total time until recovery (operationalized by a FMS score of 1 or less) between the participants who finished the task and those who dropped out earlier varied significantly – the latter needed more time to recover. However, only five subjects (all from the drop-out group) did not fully recover 15 min post exposure. Furthermore, for all of the participants there was a significant decrease of simulator sickness symptoms severity between immediately after exposure and 3 min later. Results achieved by Singer et al. (1998) support the hypothesis that the simulator sickness symptoms persist for some time after leaving the VR and then return to the baseline levels. In their study, all of the specific symptoms except disorientation (viz. nausea and oculomotor disturbance; the same effect was confirmed for the total SSQ score as well) returned to baseline levels after a 30-min rest. McCauley et al. (1990) state that the simulator sickness symptoms severity decreases after leaving the VR (between two measurement points: immediately after leaving the VR and 30 min later). Mali´nska et al. (2014) tested subjective sensations (simulator sickness and fatigue; the latter will not be discussed herein) felt after exposure to virtual reality. In this study, individual proneness to motion sickness was tested using the Coriolis test before the experimental trial. Twenty men participated in the experiment. The study was conducted in two separate phases. During the first phase, all of the participants watched a part of the “Avatar” movie – both in 2D and 3D versions. The results concerning only the impact of the movie will not be discussed herein. Possibility of Adapting VR Users in Advance It was discovered, that the simulator sickness symptoms assessed on a 0–10 scale decreased rapidly after the first exposure – the comparisons were significant for Day 1 and each of the other times and not significant for any other comparisons. It appears that the adaptation achieved by the study subjects happened between the two first sessions. What is more, that adaptation effect did not wear offwith time – on Day 22 the symptoms severity was still significantly smaller that on Day 1. The SSQ was also administered in this study and the total score, nausea and disorientation scores did significantly decrease in time. This effect, however, was visible between Day 1 – Day 4 and Day 1 – Day 5 (for the total and nausea scores) and between Day 1 – Day 4 (for the disorientation score). Furthermore, for the total and nausea scores, adaptation was retained during the last measurement on Day 22. The results of this study prove that it is possible to adapt people to VR conditions and that this effect can be long-lasting. However, the method of measurement for In light of the reviewed studies, the possibility of adapting to VR is reasonable – several authors reported results suggesting it. However, a large number of the studies did not report statistical tests proving this claim or reported statistical non- significance. Various adaptation patterns have been observed – the effect was visible when all of the VR immersions were conducted on a single day (Lampton et al., 2000; Domeyer et al., 2013), on separate days (e.g., Cobb et al., 1999; Brooks et al., 2010; Reinhard et al., 2017), or even during a single VR exposure (Sinitski et al., 2018). A floor effect of no symptoms November 2018 | Volume 9 | Article 2132 Frontiers in Psychology | www.frontiersin.org 9 Can Simulator Sickness Be Avoided? Du˙zma ´nska et al. after some exposures was observed by Kennedy et al. (2000). The effect of adaptation does not wear with time, as in was observed by Newman et al. (2013). Furthermore, virtual reality is not necessarily essential for evoking the adaptation effect (Smither et al., 2008). 6 participants reported experiencing other symptoms, which cannot be classified as typical simulator sickness symptoms (visual flashbacks, unsteadiness or symptoms different from the ones experienced during the VR exposure). Unfortunately, no information on the VR exposure length was given by the authors. Possibility of Adapting VR Users in Advance The patterns and extents to which adaptation was observed in the aforementioned studies are diversified. Certainly, further research on this issue is necessary. It is also intriguing what is the relationship between possible adaptation along with subsequent VR experiences and increasing severity of simulator sickness during one long experience. These relationships would be worth testing in future studies. In the study by Moss and Muth (2011), more widely described above, it was discovered that the simulator sickness symptoms persist for some time after leaving the virtual reality environment. The total SSQ score in this study measured 10 min post exposure was still significantly higher than the baseline score. This means, that for the virtual reality environment tested in the study, not only did the simulator sickness’ symptoms increase with time, but they also persisted for at least 10 min after leaving the virtual reality. Therefore, it cannot be confirmed when did the symptoms subside. However, in a similar study by Moss et al. (2011), the severity of symptoms did return to baseline level after a 10-min rest. Frontiers in Psychology | www.frontiersin.org Persistence of the Simulator Sickness Symptoms After VR Exposure In the second phase, the participants engaged in a virtual reality task, which included transporting various elements on a virtual workstation. A questionnaire created by the authors of the study was used as a method of measurement for A more detailed, qualitative description of the simulator sickness symptoms persistence pattern was given by Braithwaite and Braithwaite (1990). From 14 of the participants, 6 suffered from severe headaches, which lasted for 2-6 h, 2 suffered from nausea (up to 2 h after leaving the simulator) and November 2018 | Volume 9 | Article 2132 10 Can Simulator Sickness Be Avoided? Du˙zma ´nska et al. the simulator sickness. It included 8 symptoms (e.g., eye pain, headache, dizziness, nausea), which were assessed on a five-point scale. This questionnaire was conducted thrice – straight after the simulator exposure, 20 min and up to 24 h later (and sent by email). 20 min post exposure, 7 of 8 simulator sickness symptoms were reported by at least one participant. No one experienced increased sweating and the most prevalent symptoms were: eye pain, drowsiness, fatigue and apathy. According to the results, the participants experienced the simulator sickness symptoms up to 4 h after completing the virtual reality task. Reported symptoms included: headache, dizziness, disorientation and drowsiness. Unfortunately, no comparison between the different time periods was given, and therefore any conclusions drawn from this study regarding the temporal aspects of simulator sickness should be treated with extreme caution. The results of the studies concentrated on simulator sickness persistence are given in the Supplementary Table S3. some time after exposure, although it remains unknown for how long and it may vary depending on the initial severity of the symptoms. Apart from the points concerning each specific temporal aspect of simulator sickness, some general conclusions can be drawn. The virtual reality technology and simulators still have the tendency to evoke unpleasant symptoms among their users; although the technology advances, this problem has not yet been solved. It is the most vivid for the first aspect discussed herein – the temporal trajectory of the progression of simulator sickness – the severity of symptoms grows along exposure time both in the studies conducted almost 20 years ago (Cobb et al., 1999) and in the most recent ones (Lee et al., 2017). 4Steam (https://store.steampowered.com) is a digital distribution platform, on which various types of games can be bought, played and stored in a cloud. CONCLUSION To summarize the conclusions reached about each of the temporal aspects of simulator sickness, a sufficient amount of evidence appears to exist in order to confirm the hypothesis that the severity of simulator sickness symptoms increases with increased exposure time. There appears to be no universal rule regarding maximum exposure time until unpleasant symptoms are evoked. A correct direction of research in this aspect would be to test the temporal pattern of simulator sickness progression for each VR technology separately – as it has been reported by Lee et al. (2017), different devices used for controlling the individual’s movement in the virtual environment tend to evoke slightly different levels of simulator sickness. Despite the development of technology, the issue of simulator sickness appears to still remain unsolved. Interesting trends have been reported – in some studies, the simulator sickness severity either begins to stabilize (e.g., Moss et al., 2008) or decreases (e.g., Sinitski et al., 2018) after some time and in other – the symptoms become noticeably unpleasant after some time spent in the VR (e.g., Min et al., 2004). As it has been broadly discussed above, adaptation to the VR environment appears to be possible, but the quoted studies do not provide conclusive data – further inquiry regarding this topic is necessary. Some simulator sickness symptoms may prevail for The researchers and developers employing the virtual reality technology should always bear in mind the fact that simulator sickness exists and can disturb the desired outcomes. Therefore, before it becomes widely implemented, every VR technology needs to be tested for its tendency to evoke unpleasant symptoms in its users in the three temporal aspects discussed above. Persistence of the Simulator Sickness Symptoms After VR Exposure Although this trend appears to be stable regardless the technological progress, such statements should be treated with caution, as the studies used various types of VR technologies, which may not be comparable. Until the technology reaches the point when the simulator sickness will be wholly preventable, some standards should be developed when it comes to research on virtual reality and simulators. The issue of how often the simulator sickness symptoms should be measured (not only during the experimental trial, but also after it), should be addressed. Regarding simulator sickness persistence, it may be assumed that at least some of the symptoms may prevail after the exposure (10 min, Moss et al., 2011; circa 30 min, Singer et al., 1998; more than 30 min, Biernacki and Dziuda, 2014; Dziuda et al., 2014), in some cases even for relatively long time (more than 4 h after approximately 2 h of exposure, Mali´nska et al., 2014; for even 4 h after leaving the VR, Braithwaite and Braithwaite, 1990). On the other hand, the results of Biernacki and Dziuda (2014) suggest that the severity of symptoms changes rapidly – it is increased directly after exposure, but significantly decreased 30 min afterward. The time of the symptoms’ prevalence differs between various VR environments. Furthermore, the length of recovery depends on the initial symptoms’ severity – it takes longer to fully recover, when the experienced symptoms were more severe (Bos et al., 2005; Keshavarz et al., 2018). It would be advisable to test the tendency of a new virtual reality tool to evoke the simulator sickness symptoms in the three above discussed dimensions: temporal pattern of the symptoms’ progression, adaptation possibility and persistence of symptoms after exposure. These parameters would provide vital information on how long the training, game or any other scenarios should be, in order to provide the user with an enjoyable experience and to prevent unpleasant sensations. This issue appears to be exceptionally crucial for professional training simulators, where the quality of the experience may have an influence on results of the training session. Furthermore, the physiological measurement of simulator sickness should be developed and given more focus, as it might be more precise and less biased than a self-report. Frontiers in Psychology | www.frontiersin.org Practical Implications for Further Research The above described research provides interesting insight into the temporal aspects of the simulator sickness and it appears that there are still issues which demand further inquiry. First of all, most of the research concerns driving or flight simulators, most often used for training professional drivers and pilots, but the virtual reality technology is advancing rapidly and has already been applied to the gaming industry (2.704 titles on Steam4 when the searching parameters were restricted to “VR only” and 3.243 with the “VR supported” search restriction; data collected on June 14, 2018) – creating a brand-new field for research. It would be November 2018 | Volume 9 | Article 2132 Frontiers in Psychology | www.frontiersin.org Frontiers in Psychology | www.frontiersin.org 11 Can Simulator Sickness Be Avoided? Du˙zma ´nska et al. advisable to explore the temporal aspects of simulator sickness, not only on professional training simulators and professional drivers and pilots, but also on virtual reality-supported games and everyday, non-professional VR users and gamers. A significant number of the reviewed studies turned out to have drawbacks or did not include as thorough analysis of the temporal aspects of simulator sickness as it may have been expected, which can be considered a limitation of the present review. Very often the study reports did not include any information on statistical significance of the results, or the sample size was extremely small, which made it impossible to draw definite conclusions. Furthermore, as the temporal aspects of simulator sickness is most often analyzed alongside other study objectives, it is possible that some interesting results on the topic have been omitted in the search process. Despite these limitations, the present review is believed to give insight into the temporal aspects of simulator sickness and serve as a basis for further research focused on temporal aspects of simulator sickness. It would also be advisable to further explore the temporal aspects of simulator sickness and to develop a standardized methodology which would allow a comparison between studies focusing on different virtual reality environments. Researchers should bear in mind the need to compare the SSQ scores between time periods [a good example of such methodology is the Moss and Muth (2011) study, where simulator sickness severity was assessed each 5 min] and to control the severity of symptoms for several hours after virtual reality exposure, in order to be able to determine the moment when the symptoms subside. Practical Implications for Further Research Moreover, it would be intriguing to compare the effect of one prolonged VR exposure to a number of shorter exposures, summing up to the same total time. According to the evidence found in past studies, it could be expected that the severity of symptoms after one long exposure should be greater than after a series of short ones. A pattern of symptoms’ persistence after such two types of exposures could also be explored. FUNDING This work was co-financed by the Polish National Centre for Research and Development under the grant “Widespread Disaster Simulator – research and preparation for implementation” (project number POIR.01.01.01-00.0042/16; the Smart Growth Operational Programme, sub-measure 1.1.1. Industrial research and development work implemented by enterprises) received by Nano Games sp. z o.o. Strengths and Limitations The main strength of the present paper is that it covers a very wide array of study reports – not only from the most recent times, but also the older ones, from the 1990s. Consideration has been taken to analyze all the results thoroughly. Caution has been exercised to allow for any possible bias and limitations of every single study. Moreover, efforts have been taken to shed more light on the subject which, despite being an important factor of simulator and VR experience, has not been given much attention in research. FIGURE S1 | Flow chart of the search and screening process for the relevant literature. FIGURE S1 | Flow chart of the search and screening process for the relevant literature. TABLE S1 | Studies focusing on the temporal trajectory of the progression of simulator sickness. TABLE S1 | Studies focusing on the temporal trajectory of the progression of simulator sickness. TABLE S2 | Studies focusing on the possibility of adapting VR users in advance. TABLE S2 | Studies focusing on the possibility of adapting VR users in advance. TABLE S2 | Studies focusing on the possibility of adapting VR users in advance. TABLE S3 | Studies focusing on how long the simulator sickness persists after VR exposure. AUTHOR CONTRIBUTIONS ND wrote major part of the paper, contributed to the conception and design of the review. PS designed the review and wrote minor part of the paper. AS contributed to the conception and design of the review. All authors listed have made substantial intellectual contribution to the work, revised the manuscript, read and approved the submitted version. It is also worth suggesting that the simulator sickness severity should be assessed not only before the experimental procedure, but also after the initial training phase, in order to establish if the training could serve as the adaptation period. In light of the past research which suggest that most of the people suffer from simulator sickness to some extent, the researchers should care for the study participants, who report strong and unpleasant symptoms not only straight after the experimental procedure, but also as long as the symptoms persist. Brooks et al. (2010) propose a number of means that can be taken in order to provide the participants with proper care. Supplies such as sick bags, plastic gloves, mouthwash and cleaning products should be kept in the lab. The participants should be provided with light snacks and water. They should also be advised not to drive a car until they feel that all the symptoms have subsided. Brooks et al. (2010) suggest as well that the participants should stay in the lab for at least an hour after the experiment. It would also be advisable to contact the participants after the study and ask them if they experienced any unpleasant side-effects of VR exposure. SUPPLEMENTARY MATERIAL The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fpsyg. 2018.02132/full#supplementary-material REFERENCES sickness and pathfinding,” in Proceedings of the 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) (Monterey, CA: IEEE), 4175–4178. doi: 10.1109/EMBC.2017.803 7776 sickness and pathfinding,” in Proceedings of the 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) (Monterey, CA: IEEE), 4175–4178. doi: 10.1109/EMBC.2017.803 7776 Aldaba, C. N., White, P. J., Byagowi, A., and Moussavi, Z. (2017). “Virtual reality body motion induced navigational controllers and their effects on simulator November 2018 | Volume 9 | Article 2132 Frontiers in Psychology | www.frontiersin.org 12 Du˙zma ´nska et al. Can Simulator Sickness Be Avoided? Anderson-Hanley, C., Snyder, A. L., Nimon, J. P., and Arciero, P. J. (2011). Social facilitation in virtual reality-enhanced exercise: competitiveness moderates exercise effort of older adults. Clin. Interv. Aging 6, 275–280. doi: 10.2147/CIA. S25337 Domeyer, J. E., Cassavaugh, N. D., and Backs, R. W. (2013). The use of adaptation to reduce simulator sickness in driving assessment and research. Accid. Anal. Prev. 53, 127–132. doi: 10.1016/j.aap.2012.12.039 Dziuda, Ł, Biernacki, M. P., Baran, P. M., and Truszczy´nski, O. E. (2014). The effects of simulated fog and motion on simulator sickness in a driving simulator and the duration of after-effects. Appl. Ergon. 45, 406–412. doi: 10.1016/j. apergo.2013.05.003 Bailenson, J. N., and Yee, N. (2006). A longitudinal study of task performance, head movements, subjective report, simulator sickness, and transformed social interaction in collaborative virtual environments. Presence 15, 699–716. doi: 10.1162/pres.15.6.699 and the duration of after-effects. Appl. Ergon. 45, 406–412. doi: 10.1016/j. apergo.2013.05.003 g Ebenholtz, S. M. (1992). Motion sickness and oculomotor systems in virtual environments. Presence 1, 302–305. doi: 10.1162/pres.1992.1.3.302 Biernacki, M., and Dziuda, Ł (2012). Choroba symulatorowa jako realny problem bada´n na symulatorach. Med. Pr. 63, 377–388. Ebenholtz, S. M. (2001). Oculomotor Systems and Perception. New York, Ebenholtz, S. M. (2001). Oculomotor Systems and Perception. New York, NY: Cambridge University Press. doi: 10.1017/CBO978051152 9795 y p NY: Cambridge University Press. doi: 10.1017/CBO978051152 9795 Biernacki, M., and Dziuda, Ł (2014). Mood and simulator sickness after truck simulator exposure. Int. J. Occup. Med. Environ. Health 27, 278–292. doi: 10. 2478/s13382-014-0251-2 Feenstra, P. J., Bos, J. E., and van Gent, R. N. (2011). A visual display enhancing comfort by counteracting airsickness. Displays 32, 194–200. doi: 10.1016/j. displa.2010.11.002 Biernacki, M. P., Kennedy, R. S., and Dziuda, Ł (2016). Zjawisko choroby symulatorowej oraz jej pomiar na przykładzie kwestionariusza do badania choroby symulatorowej–SSQ. Med. Pr. REFERENCES M., Kantor, L., and Megee, L. E. (1989). Limitations of postural equilibrium tests for examining simulator sickness. Aviat. Space Environ. Med. 59, 246–251. and Visualization, Tianjin, 486–488. doi: 10.1109/CGIV.2009.8 Helland, A., Lydersen, S., Lervåg, L. E., Jenssen, G. D., Mørland, J., and Slørdal, L. (2016). Driving simulator sickness: impact on driving performance, influence of blood alcohol concentration, and effect of repeated simulator exposures. Accid. Anal. Prev. 94, 180–187. doi: 10.1016/j.aap.2016. 05.008 Bruck, S., and Watters, P. A. (2011). The factor structure of cybersickness. Displays 32, 153–158. doi: 10.1016/j.displa.2011.07.002 Brunnström, K., Wang, K., Tavakoli, S., and Andrén, B. (2017). Symptoms analysis of 3D TV viewing based on simulator sickness questionnaires. Qual. User Exp. 2, 1–15. doi: 10.1007/s41233-016-0003-0 Hollander, R. (2018). The VR Hardware Report: How stand-alone VR headsets will Usher in Mainstream Adoption Beginning in 2018. Available at: https://www. businessinsider.com/the-vr-hardware-report-2018-3?IR=T Choi, M. H., Lee, S. J., Kim, H. S., Yang, J. W., Choi, J. S., Tack, G. R., et al. (2009). “Long-term study of simulator sickness: differences in psychophysiological responses due to individual sensitivity,” in Proceedings of the 2009 International Conference on Mechatronics and Automation, Changchun, 20–25. doi: 10.1109/ ICMA.2009.5246734 Jaeger, B. K., and Mourant, R. R. (2001). Comparison of simulator sickness using static and dynamic walking simulators. Proc. Hum. Factors Ergon. Soc. Annu. Meet. 45, 1896–1900. doi: 10.1177/154193120104502709 Chung, S. C., You, J. H., Kwon, J. H., Lee, B., Tack, G. R., Yi, J. H., et al. (2007). Differences in psychophysiological responses due to simulator sickness sensitivity. Proceedings of the 2006 World Congress on Medical Physics and Biomedical Engineering, Berlin, 1218–1221. doi: 10.1007/978-3-540-36841- 0_294 Jarchow, T., and Young, L. R. (2007). Adaptation to head movements during short radius centrifugation. Acta Astronaut. 61, 881–888. doi: 10.1016/j.actaastro. 2006.12.022 Jayaram, S., Connacher, H. I., and Lyons, K. W. (1997). Virtual assembly using virtual reality techniques. Comput. Aided Des. 29, 575–584. doi: 10.1016/S0010- 4485(96)00094-2 Classen, S., Bewernitz, M., and Shechtman, O. (2011). Driving simulator sickness: an evidence-based review of the literature. Am. J. Occup. Ther. 65, 179–188. doi: 10.5014/ajot.2011.000802 Kennedy, R. S., Lane, N. E., Berbaum, K. S., and Lilienthal, M. G. (1993). Simulator sickness questionnaire: an enhanced method for quantifying simulator sickness. Int. J. Aviat. Psychol. 3, 203–220. doi: 10.1207/s15327108ijap0303_3 Classen, S., and Owens, A. B. (2010). Simulator sickness among returning combat veterans with mild traumatic brain injury and/or post-traumatic stress disorder. Adv. Transp. Stud. 45–52. Kennedy, R. S., Stanney, K. REFERENCES 67, 545–555. doi: 10.13075/mp.5893. 00512 Gavgani, A. M., Nesbitt, K. V., Blackmore, K. L., and Nalivaiko, E. (2016). Profiling subjective symptoms and autonomic changes associated with cybersickness. Auton. Neurosci. 203, 41–50. doi: 10.1016/j.autneu.2016.12.004 Bliss, J. P., Tidwell, P. D., and Guest, M. A. (1997). The effectiveness of virtual reality for administering spatial navigation training to firefighters. Presence 6, 73–86. doi: 10.1162/pres.1997.6.1.73 Gerardi, M., Cukor, J., Difede, J., Rizzo, A., and Rothbaum, B. O. (2010). Virtual reality exposure therapy for post-traumatic stress disorder and other anxiety disorders. Curr. Psychiatry Rep. 12, 298–305. doi: 10.1007/s11920-010-0 128-4 Bos, J. E., MacKinnon, S. N., and Patterson, A. (2005). Motion sickness symptoms in a ship motion simulator: effects of inside, outside, and no view. Aviat. Space Environ. Med. 76, 1111–1118. Häkkinen, J., Liinasuo, M., Takatalo, J., and Nyman, G. (2006a). “Visual comfort with mobile stereoscopic gaming,” Proceedings of the SPIE, Stereoscopic Displays and Virtual Reality Systems XIII, eds A. J. Woods, N. A. Dodgson, J. O. Merritt, M. T. Bolas, and I. E. McDowall (Bellingham, WA: SPIE). doi: 10.1117/12. 641210 Braithwaite, M. G., and Braithwaite, B. D. (1990). Simulator sickness in an army simulator. Occup. Med. 40, 105–110. doi: 10.1093/occmed/40.3.105 Bric, J. D., Lumbard, D. C., Frelich, M. J., and Gould, J. C. (2016). Current state of virtual reality simulation in robotic surgery training: a review. Surg. Endosc. 30, 2169–2178. doi: 10.1007/s00464-015-4517-y Häkkinen, J., Pölönen, M., Takatalo, J., and Nyman, G. (2006b). “Simulator sickness in virtual display gaming: a comparison of stereoscopic and non- stereoscopic situations,” in Proceedings of the 8th Conference on Human- Computer Interaction with Mobile Devices and Services (Helsinki: ACM Press), 227–230. doi: 10.1145/1152215.1152263 Brooks, J. O., Goodenough, R. R., Crisler, M. C., Klein, N. D., Alley, R. L., Koon, B. L., et al. (2010). Simulator sickness during driving simulation studies. Accid. Anal. Prev. 42, 788–796. doi: 10.1016/j.aap.2009.04.013 Bruck, S., and Watters, P. A. (2009a). Cybersickness and anxiety during simulated motion: implications for VRET. Annu. Rev. Cyber Ther. Telemed. 144, 169–173. doi: 10.3233/978-1-60750-017-9169 Häkkinen, J., Vuori, T., and Puhakka, M. (2002). “Postural stability and sickness symptoms after HMD use,” Proceedings of the IEEE International Conference on Systems, Man and Cybernetics, Hammamet, 147–152. Bruck, S., and Watters, P. A. (2009b). “Estimating cybersickness of simulated motion using the simulator sickness questionnaire (SSQ): a controlled study,” in Proceedings of the 6th International Conference on Computer Graphics, Imaging and Visualization, Tianjin, 486–488. doi: 10.1109/CGIV.2009.83 Hamilton, K. REFERENCES M., and Dunlap, W. P. (2000). Duration and exposure to virtual environments: sickness curves during and across sessions. Presence 9, 463–472. doi: 10.1162/105474600566952 p Cobb, S. V., Nichols, S., Ramsey, A., and Wilson, J. R. (1999). Virtual reality- induced symptoms and effects (VRISE). Presence 8, 169–186. doi: 10.1162/ 105474699566152 Keshavarz, B., Ramkhalawansingh, R., Haycock, B., Shahab, S., and Campos, J. L. (2018). Comparing simulator sickness in younger and older adults during simulated driving under different multisensory conditions. Transp. Res. Part F 54, 47–62. doi: 10.1016/j.trf.2018.01.007 Dahlman, J., Sjörs, A., Ledin, T., and Falkmer, T. (2008). Could sound be used as a strategy for reducing symptoms of perceived motion sickness? J. Neuroeng. Rehabil. 5:35. doi: 10.1186/1743-0003-5-35 Dahlman, J., Sjörs, A., Lindström, J., Ledin, T., and Falkmer, T. (2009). Performance and autonomic responses during motion sickness. Hum. Factors 51, 56–66. doi: 10.1177/0018720809332848 Kim, Y. Y., Kim, H. J., Kim, E. N., Ko, H. D., and Kim, H. T. (2005). Characteristic changes in the physiological components of cybersickness. Psychophysiology 42, 616–625. doi: 10.1111/j.1469-8986.2005.00349.x November 2018 | Volume 9 | Article 2132 Frontiers in Psychology | www.frontiersin.org 13 Du˙zma ´nska et al. Can Simulator Sickness Be Avoided? due to individual sensitivity. Int. J. Neurosci. 118, 857–865. doi: 10.1080/ 00207450701239459 Kolasinski, E. M. (1995). Simulator Sickness in Virtual Environments. Alexandria, VA: U.S. Army Research Institute for the Behavioral and Social Sciences. doi: 10.21236/ADA295861 due to individual sensitivity. Int. J. Neurosci. 118, 857–865. doi: 10.1080/ 00207450701239459 Reason, J. T. (1978). Motion sickness adaptation: a neural mismatch model. J. R. S M d 71 819 829 d i 10 1177/014107687807101109 Reason, J. T. (1978). Motion sickness adaptation: a neural mism Soc. Med. 71, 819–829. doi: 10.1177/014107687807101109 Soc. Med. 71, 819–829. doi: 10.1177/014107687807101109 Lampton, D. R., Kolasinski, E. M., Knerr, B. W., Bliss, J. P., Bailey, J. H., and Witmer, B. G. (1994). Side effects and aftereffects of immersion in virtual environments. Proc. Hum. Factors Ergon. Soc. Annu. Meet. 38, 1154–1157. doi: 10.1177/154193129403801802 eason, J. T., and Brand, J. J. (1975). Motion Sickness. Oxford: Aca Reason, J. T., and Brand, J. J. (1975). Motion Sickness. Oxford: Academic Press. Reinhard, R., Rutrecht, H. M., Hengstenberg, P., Tutulmaz, E., Geissler, B., Hecht, H., et al. (2017). The best way to assess visually induced motion sickness in a fixed-base driving simulator. Transp. Res. Part F 48, 74–88. doi: 10.1016/j. trf.2017.05.005 Lampton, D. R., Rodriguez, M. E., and Cotton, J. E. (2000). REFERENCES Simulator sickness symptoms during team training in immersive virtual environments. Proc. Hum. Factors Ergon. Soc. Annu. Meet. 44, 530–533. doi: 10.1177/154193120004400512 Riccio, G. E., and Stoffregen, T. A. (1991). An ecological theory of motion sickness and postural stability. Ecol. Psychol. 3, 195–240. doi: 10.1207/ s15326969eco0303_2 Lee, J., Kim, M., and Kim, J. (2017). A study on immersion and VR sickness in walking interaction for immersive virtual reality applications. Symmetry 9:78. doi: 10.3390/sym9050078 Serge, S. R., and Moss, J. D. (2015). Simulator sickness and the oculus rift: a first look. Proc. Hum. Factors Ergon. Soc. Annu. Meet. 59, 761–765. doi: 10.1177/ 1541931215591236 Lin, J. W., Duh, H. B. L., Parker, D. E., Abi-Rached, H., and Furness, T. A. (2002). Effects of field of view on presence, enjoyment, memory, and simulator sickness in a virtual environment. Proceedings of the IEEE Virtual Reality Conference, Orlando, FL, 164–171. doi: 10.1109/VR.2002.996519 Sharples, S., Cobb, S., Moody, A., and Wilson, J. R. (2008). Virtual reality induced symptoms and effects (VRISE): comparison of head mounted display (HMD), desktop and projection display systems. Displays 29, 58–69. doi: 10.1016/j. displa.2007.09.005 Lo, W. T., and So, R. H. (2001). Cybersickness in the presence of scene rotational movements along different axes. Appl. Ergon. 32, 1–14. doi: 10.1016/S0003- 6870(00)00059-4 Singer, M. J., Ehrlich, J. A., and Allen, R. C. (1998). Virtual environment sickness: adaptation to and recovery from a search task. Proc. Hum. Factors Ergon. Soc. Annu. Meet. 42, 1506–1510. doi: 10.1177/15419312980420 2109 Łukowska, M. (2011). Zastosowanie technologii wirtualnej rzeczywisto´sci w psychologii. Rocznik Kognitywistyczny 5, 103–108. Mali´nska, M., Zu˙zewicz, K., Bugajska, J., and Grabowski, A. (2014). Subiektywne odczucia wskazuja¸ce na wyst˛epowanie choroby symulatorowej i zm˛eczenie po ekspozycji na rzeczywisto´s´c wirtualn ˛a. Med. Pr. 65, 361–371. doi: 10.13075/mp. 5893.2014.041 Sinitski, E., Thompson, A. A., Godsell, P. C., Honey, J. L. N., and Besemann, M. (2018). Postural stability and simulator sickness after walking on a treadmill in a virtual environment with a curved display. Displays 52, 1–7. doi: 10.1016/j. displa.2018.01.001 McCauley, M., Hettinger, L., Sharkey, T., and Sinacori, J. (1990). “The effects of simulator visual-motion asynchrony on simulator induced sickness,” in Proceedings of the Flight Simulation Technologies Conference and Exhibit, Dayton, OH. doi: 10.2514/6.1990-3172 Smither, J. A. A., Mouloua, M., and Kennedy, R. (2008). Reducing symptoms of visually induced motion sickness through perceptual training. Int. J. Aviat. Psychol. 18, 326–339. doi: 10.1080/105084108023 46921 Min, B. C., Chung, S. C., Min, Y. REFERENCES K., and Sakamoto, K. (2004). Psychophysiological evaluation of simulator sickness evoked by a graphic simulator. Appl. Ergon. 35, 549–556. doi: 10.1016/j.apergo.2004.06.002 So, R. H., Lo, W. T., and Ho, A. T. (2001). Effects of navigation speed on motion sickness caused by an immersive virtual environment. Hum. Factors 43, 452–461. doi: 10.1518/001872001775898223 Moss, J., Scisco, J., and Muth, E. (2008). Simulator sickness during head mounted display (HMD) of real world video captured scenes. Proc. Hum. Factors Ergon. Soc. Annu. Meet. 52, 1631–1634. doi: 10.1177/154193120805201969 Tanaka, N., and Takagi, H. (2004). Virtual reality environment design of managing both presence and virtual reality sickness. J. Physiol. Anthropol. Appl. Hum. Sci. 23, 313–317. doi: 10.2114/jpa.23.313 Moss, J. D., Austin, J., Salley, J., Coats, J., Williams, K., and Muth, E. R. (2011). The effects of display delay on simulator sickness. Displays 32, 159–168. doi: 10.1016/j.displa.2011.05.010 Treisman, M. (1977). Motion sickness: an evolutionary hypothesis. Science 197, 493–495. doi: 10.1126/science.301659 Moss, J. D., and Muth, E. R. (2011). Characteristics of head-mounted displays and their effects on simulator sickness. Hum. Factors 53, 308–319. doi: 10.1177/ 0018720811405196 Zu˙zewicz, K., Saulewicz, A., Konarska, M., and Kaczorowski, Z. (2011). Heart rate variability and motion sickness during forklift simulator driving. Int. J. Occup. Saf. Ergon. 17, 403–410. doi: 10.1080/10803548.2011.11076903 Mourant, R. R., and Thattacherry, T. R. (2000). Simulator sickness in a virtual environments driving simulator. Proc. Hum. Factors Ergon. Soc. Annu. Meet. 44, 534–537. doi: 10.1177/154193120004400513 Conflict of Interest Statement: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Nader, M., and Kruszewski, M. (2013). Wykorzystanie zaawansowanych symulatorów jazdy w badaniach zachowania i umiej˛etno´sci kierowców. Prace naukowe Politechniki Warszawskiej 96, 321–331. Copyright © 2018 Du˙zma´nska, Strojny and Strojny. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Newman, M. C., McCarthy, G. W., Glaser, S. T., Bonato, F., and Bubka, A. (2013). Motion sickness adaptation to Coriolis-inducing head movements in a sustained G flight simulator. Aviat. Space Environ. Med. 84, 104–109. doi: 10.3357/ASEM.3170.2013 Park, J. November 2018 | Volume 9 | Article 2132 REFERENCES R., Lim, D. W., Lee, S. Y., Lee, H. W., Choi, M. H., and Chung, S. C. (2008). Long-term study of simulator sickness: differences in EEG response November 2018 | Volume 9 | Article 2132 Frontiers in Psychology | www.frontiersin.org 14
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Inhibition of Aurora B by CCT137690 sensitizes colorectal cells to radiotherapy
Journal of experimental & clinical cancer research
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cc-by
6,345
RESEARCH Open Access Abstract Colorectal cancer is the third most commonly diagnosed cancer worldwide. Although surgery remains the best treatment for this disease, adjuvant chemotherapy and radiotherapy are also very important in clinical practice. However, the notorious refractory lack of responses to radiochemotherapy greatly limits the application of radiochemotherapy in the context of colorectal cancer. y There is a growing interest in the role that Aurora B may play in colorectal cancer cell survival as well as other cancer subtypes. In the current study, we sought to ascertain whether blocking of Aurora B signaling machinery by a small molecule inhibitor, CCT137690, could synergize radiation-induced colorectal cancer cell death. Results showed that CCT137690 increases the sensitivity of SW620 cells to radiation. Mechanistic studies revealed that Aurora B-Survivin pathway may be involved in this synergistic effect. Taken together, our results for the first time show that Aurora B inhibition and radiation exert a synergistic effect, resulting in enhanced colorectal cancer cell death. This synergistic effect is clinically relevant as lower doses of radiation could be used for cancer treatment, and could provide significant clinical benefits in terms of colorectal cancer management, while reducing unwanted side-effects. Keywords: CCT137690, Aurora B, Radiotherapy, Colorectal cancer Wu et al. Journal of Experimental & Clinical Cancer Research 2014, 33:13 http://www.jeccr.com/content/33/1/13 Wu et al. Journal of Experimental & Clinical Cancer Research 2014, 33:13 http://www.jeccr.com/content/33/1/13 Wu et al. Journal of Experimental & Clinical Cancer Research 2014, 33:13 http://www.jeccr.com/content/33/1/13 * Correspondence: dryxq186@163.com †Equal contributors 1Department of Surgical Oncology, Affiliated Hospital of Nanjing University of Traditional Chinese Medicine, 155 Guangzhou Road, Nanjing 210029, China Full list of author information is available at the end of the article Inhibition of Aurora B by CCT137690 sensitizes colorectal cells to radiotherapy Xiaoyu Wu1†, Wentao Liu2†, Qinhong Cao1, Che Chen1, Zhiwei Chen1, Zhe Xu1, Weisu Li1, Fukun Liu1 and Xuequan Yao1* © 2014 Wu et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Introduction kinases which regulate the function of centrosomes, spin- dles, and kinetochores for proper mitotic progression [9,11]. Aurora A overexpression has been observed in vari- ous cancers including colorectal cancers. Baba et. al. re- ported overexpression of Aurora A protein in 19% of CRC by immunohistochemistry [12]. High copy amplification of the Aurora A gene was found in colorectal tumors [13] and associated with chromosomal instability phenotypes [14]. In another report, up-regulation of Aurora kinases were detected in 48.5% (97/200) of patients with colorectal carcinoma [15]. Similarly, a previous study reported that the presence of nuclear Aurora B was strongly associated with lymph node metastasis in colorectal cancer [16]. In metastatic colorectal cancer, patients with a high expres- sion level of Aurora B lived significantly shorter compared with patients with a low expression level [17]. Taken to- gether, these studies highlight the association of altered aurora kinases and CRC. Colorectal cancer (CRC) is the third most commonly di- agnosed cancer worldwide with over 1.4 million new cancer cases and 0.6 million estimated deaths every year [1-3]. The incidence of CRC has rapidly increased in China and other Asian countries over the last few de- cades [4-8], and identifying better ways of treating this cancer is paramount. Although surgery of CRC remains the best treatment, adjuvant chemotherapy and radio- therapy are also very important and beneficial treat- ments for patients [9,10]. After surgery, chemotherapy and radiotherapy is used to target small cancerous tis- sues that may be missed during surgery and help to prevent cancer recurrence. Aurora kinases (of which there are 3 isoforms: Aurora A, B and C) are the most important serine/threonine-protein As far as therapeutic options, 5-Fluorouracil (5-FU) re- mains the most commonly used chemotherapeutic agent for CRC. However, CRC tumors are highly refractory to ll list of author information is available at the end of the article Wu et al. Journal of Experimental & Clinical Cancer Research 2014, 33:13 http://www.jeccr.com/content/33/1/13 Wu et al. Journal of Experimental & Clinical Cancer Research 2014, 33:13 http://www.jeccr.com/content/33/1/13 Page 2 of 9 Page 2 of 9 Anti-Histone H3 and GAPDH antibody were obtained from Santa Cruz Biotechnology. Anti-Histone H3 and GAPDH antibody were obtained from Santa Cruz Biotechnology. chemotherapy and many patients eventually relapse. Determination of surviving fraction 5 2 × 105 cells were plated in a 60-mm dish. 24 hours later, the cells were exposed to different dosages of ionization radiation. After a 6-hour recovery, one percent of the cells were re-plated in a new dish. After 10 days the number of colonies formed were counted. Introduction Be- cause of the established roles of Aurora kinases in tumor initiation and progression, many inhibitors of Aurora ki- nases have been specifically tested for the treatment of colorectal cancers in combination with 5-FU, with some currently in clinical trials [18-22]. Combination effect of radiation and CCT137690 Cells were first treated with CCT137690 at different con- centrations for 48 hours before they were exposed to dif- ferent dosages of ionization radiation. Cell culture The human colorectal adenocarcinoma cell lines, SW48 and SW620, were obtained from the American Type Culture Collection. The cells were maintained in DMEM supplemented with 10% heat inactivated FBS at 37°C, 5% CO2, and 95% humidity. Recent studies showed that overexpression of Aurora kinases might have a role in chemo- and radiotherapy resistance of cancers [23,24]. Consistent with this notion, inhibition of Aurora kinases can enhance radiation sen- sitivity of cancer cells [25,26]. For example, inhibition of Aurora B sensitizes mesothelioma cells by enhancing mitotic arrests [27] and also potently suppresses repopu- lation during fractionated irradiation of human lung cancer cell lines [28]. Reagents DMEM and fetal bovine serum (FBS) were purchased from Thermo Fisher Scientific at CHINA (Shanghai, China). 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazoliumbro- mide (MTT) was obtained from Sigma-Aldrich (Shanghai, China). Anti-Aurora B antibody and anti-Histone H3 (phospho S10) antibody were obtained from Abcam. Anti- Survivin antibody was purchased from Cell Signaling. Silencing of Aurora A and B in cells 5 1.5 × 105 cells were seeded in 60-mm plates and incu- bated for 24 h before transfection. The negative control siRNA or Aurora A or B siRNA was diluted in Opti-MEM I Reduced Serum Medium and mixed with Lipofectamine 2000 according to the manufacturer’s instructions. The mix of DNA and Lipofectamine was added to cells. After 72 hours post-transfection, expression levels of Aurora genes were determined by Real-time PCR and cells were used for different assays. The main cause of treatment failure and recurrence is resistance of cancer cells to radiation and drugs [32,33]. Since inhibition of Aurora kinases can sensitize cancer cells to radiotherapy, it is expected that combining radio- therapy and Aurora inhibition for colorectal cancers may achieve a synergistic therapeutic effects. Concomitant in- hibition of Aurora kinases and radiotherapy can also potentially decrease the dosages of either medicine or radiation, which in turns can reduce the side effects of the treatments. Therefore, in our current study we sought to explore whether the combination of radio- therapy with CCT137690 may prove efficacious in the treatment of colorectal cancer cell lines. In this way, optimized combinatorial treatment may lead to a de- crease in the requirement of CCT137690 for thera- peutic benefit. Ionization radiation ll l d Cells were plated in dishes, and then irradiated with X-ray (104.93 cGy/min at 210 kV and 12 mA) by using an X-ray irradiator (MBR-1505R2; Hitachi Medico, Tokyo, Japan) for indicated dosages. Materials and methods The authors declared that the current research has been approved by The Ethics Committee of Nanjing University of Traditional Chinese Medicine. Plasmids and transfection The full-length cDNA sequence of survivin was amp- lified from total RNA of SW620 cells by using Reverse Transcription PCR. The fragment was inserted into pBABE-Puro vector. The control vector plasmid or the plasmid encoding survivin was transfected into Phoenix Retroviral Expression System. Virus was produced and ap- plied onto target cells according to the standard protocol. The cells were subjected to drug-selection for 3 days (0.5 μg/ml of puromycin) to enrich for the desired cells. CCT137690 is a newly synthesized compound which has been shown to inhibit the activities of Aurora ki- nases. IC50 values of CCT137690 are 15 and 25 nM for Aurora A and B, respectively. Although CCT137690 has shown promising therapeutic effects on different cancer cells (especially for colorectal cancer) [29-31], a narrow safety margin (due to its activity against hERG ion-channel) may limit its preclinical development [28]. Cell cycle assay Cells were collected by trypsinization and washed with PBS, centifuged and then resuspended in 0.4 ml of PBS and fixed by adding 1ml cold ethanol slowly. Cells were Page 3 of 9 Page 3 of 9 Wu et al. Journal of Experimental & Clinical Cancer Research 2014, 33:13 http://www.jeccr.com/content/33/1/13 in the dark. Samples then were measured on a Guava System (Millipore). The data were analyzed by using the software provided by the company. kept at 4°C overnight. For analysis, cell suspensions were centrifuged at 1500 rpm for 5 mins, washed with PBS and re-suspended in 500 μl staining solution (PBS with 50 μg/ ml PI together with 50 μg/ml RNase A) at 37°C for 30 mins in the dark. Cells were analyzed by flow cytometry. MTT assay for cell viability 4 104 cells were seeded into 96-well plates and were treated to either vehicle (DMSO) or different concentrations of CCT137690 for 48 hours. Cell viability was determined and quantified by using MTT assay. Results In the current study, we sought to identify whether the combination of radiotherapy and inhibition of Aurora ki- nases could exert a synergistic inhibitory effect on colo- rectal cancer cell growth. To test this hypothesis, we first characterized the sensitivity of two different colo- rectal cancer cell lines SW-48 and SW-620 to an Aurora kinase inhibitor, CCT137690. We show that both SW- 48 and SW-620 exhibit dose-dependent responses to CCT137690 treatment. Moreover, we found that SW- 620 is relatively more resistant to CCT137690 treatment as compared to SW-48 cells as manifested by a higher IC50 (430 nM vs 157 nM) (Figure 1A). In addition, when cells were treated with CCT137690 at their respective Guava Nexin assay To determine sensitivity of the cell lines to radiother- apy, GUAVA assay was employed and revealed that radi- ation was able to induce significant apoptosis in both SW-48 and SW-620 cell lines (Figure 2B-G). However, the cell lines displayed different sensitivities to IR: SW- 620 cells exhibits a higher resistance to radiation compared to SW-48 cells (Figure 2A). Indeed, higher amounts of ra- diation (3 Gy vs 1 Gy) were required for a similar apoptosis response in SW-620 cell vs SW-48 cell (Figure 2F and G). To test whether there is any synergistic effects of radio- therapy and Aurora kinase inhibition, SW620 cells were treated with different concentrations of CCT137690 be- fore they were treated with a low-dose radiation (1 Gy) or without IR (Figure 3A). Our data suggested that a low- dose radiation dramatically enhances the inhibitory effect of CCT137690 on cell growth. 100 nM of CCT137690 has very limited effects on SW620. But surprisingly, To determine sensitivity of the cell lines to radiother- apy, GUAVA assay was employed and revealed that radi- ation was able to induce significant apoptosis in both SW-48 and SW-620 cell lines (Figure 2B-G). However, the cell lines displayed different sensitivities to IR: SW- 620 cells exhibits a higher resistance to radiation compared to SW-48 cells (Figure 2A). Indeed, higher amounts of ra- diation (3 Gy vs 1 Gy) were required for a similar apoptosis response in SW-620 cell vs SW-48 cell (Figure 2F and G). Since CCT137690 inhibits the activities of both Aurora A and Aurora B, we wished to clarify whether the syner- gistic effects of CCT137690 to radiation were due to in- hibition of Aurora A or Aurora B. We therefore used siRNA to deplete either Aurora A or Aurora B in SW620 cells (Figure 5A and B). As shown in Figure 5C, only knockdown of Aurora B dramatically decreases cell sur- vival following radiation (p < 0.001) while knockdown of Aurora A does not exert a similar effect (Figure 5C). We found that radiation induced Aurora B protein expression and correspondingly higher Aurora B activity, as manifested To test whether there is any synergistic effects of radio- therapy and Aurora kinase inhibition, SW620 cells were treated with different concentrations of CCT137690 be- fore they were treated with a low-dose radiation (1 Gy) or without IR (Figure 3A). Wu et al. Journal of Experimental & Clinical Cancer Research 2014, 33:13 http://www.jeccr.com/content/33/1/13 Guava Nexin assay The Guava Nexin assay was performed following manu- factory protocol (Millipore). Briefly, attached and sus- pended cells were all collected. Cells were resuspended in 100 μL of medium and incubated together with 100 μL of Guava Nexin Reagent for 20 minutes at room temperature Figure 1 The effects of CCT37690 on proliferation of SW48 and SW620 cells. A, relative cell viabilities of SW48 and SW620 cells treated by different concentrations of CCT137690 were measured by using MTT assay. B, representative figures of cell cycle assays; SW48 with (157 nM) or without drug-treatment, SW620 with (430 nM) or without drug-treatment. C and D, quantification of cell cycle assays; C for SW48, D for SW620, mean ± SD, (n = 3). Figure 1 The effects of CCT37690 on proliferation of SW48 and SW620 cells. A, relative cell viabilities of SW48 and SW620 cells treated by different concentrations of CCT137690 were measured by using MTT assay. B, representative figures of cell cycle assays; SW48 with (157 nM) or without drug-treatment, SW620 with (430 nM) or without drug-treatment. C and D, quantification of cell cycle assays; C for SW48, D for SW620, mean ± SD, (n = 3). Figure 1 The effects of CCT37690 on proliferation of SW48 and SW620 cells. A, relative cell viabilities of SW48 and SW620 cells treated by different concentrations of CCT137690 were measured by using MTT assay. B, representative figures of cell cycle assays; SW48 with (157 nM) or without drug-treatment, SW620 with (430 nM) or without drug-treatment. C and D, quantification of cell cycle assays; C for SW48, D for SW620, mean ± SD, (n = 3). Page 4 of 9 Page 4 of 9 Wu et al. Journal of Experimental & Clinical Cancer Research 2014, 33:13 http://www.jeccr.com/content/33/1/13 IC50, we observed cell cycle perturbations in both cell lines. There was a lower proportion of cells in G1/G0 and S phase, and a higher proportion of cells in G2/M and > G2 (Figure 1B-D). when combined with radiation, a big proportion of the cells treated with CCT137690 died through apoptosis (Figure 3D). In light of these observations, we ascertained whether low-dose CCT137690 pretreatment could exert a similar effect to radiation. As shown in Figure 4A, 100 nM of CCT137690 pre-treatment dramatically decreases survival of SW620 cells exposed to radiation. In line with this no- tion, we also found that CCT137690 pre-treatment dramat- ically enhances radiation-induced apoptosis (Figure 4B-D). Guava Nexin assay Our data suggested that a low- dose radiation dramatically enhances the inhibitory effect of CCT137690 on cell growth. 100 nM of CCT137690 has very limited effects on SW620. But surprisingly, Figure 2 The effects of radiation on SW48 and SW620 cells. A, surviving curves of cells after ionization-radiation. B and C, representative figures of Guava Nexin assay of SW48 cells, B is for cells without radiation while C is for cells with 1 Gy of radiation. D and E, representative figures of Guava Nexin assay of SW620 cells, D is for cells without radiation while E is for cells with 3 Gy of radiation. F and G, quantification of Guava Nexin assays, F for SW48, G for SW620, mean ± SD, (n = 3). Figure 2 The effects of radiation on SW48 and SW620 cells. A, surviving curves of cells after ionization-radiation. B and C, representative figures of Guava Nexin assay of SW48 cells, B is for cells without radiation while C is for cells with 1 Gy of radiation. D and E, representative figures of Guava Nexin assay of SW620 cells, D is for cells without radiation while E is for cells with 3 Gy of radiation. F and G, quantification of Guava Figure 2 The effects of radiation on SW48 and SW620 cells. A, surviving curves of cells after ionization-radiation. B and C, representative figures of Guava Nexin assay of SW48 cells, B is for cells without radiation while C is for cells with 1 Gy of radiation. D and E, representative figures of Guava Nexin assay of SW620 cells, D is for cells without radiation while E is for cells with 3 Gy of radiation. F and G, quantification of Guava Nexin assays, F for SW48, G for SW620, mean ± SD, (n = 3). Wu et al. Journal of Experimental & Clinical Cancer Research 2014, 33:13 http://www.jeccr.com/content/33/1/13 Page 5 of 9 Figure 3 Low-dose radiation can increase the sensitivity of SW620 to CCT137690. A, SW620 cells were treated with different concentrations of CCT137690 for 48 hours before they were treated with (1 Gy) or without radiation. B and C, representative figures of Guava Nexin assays of cells pre-treated with 100 nM of CCT137690 and then treated with (C) or without (B) radiation. D, quantification of Guava Nexin assays on above cells, mean ± SD, (n = 3). Guava Nexin assay Figure 3 Low-dose radiation can increase the sensitivity of SW620 to CCT137690. A, SW620 cells were treated with different concentrations of CCT137690 for 48 hours before they were treated with (1 Gy) or without radiation. B and C, representative figures of Guava Nexin assays of cells pre-treated with 100 nM of CCT137690 and then treated with (C) or without (B) radiation. D, quantification of Guava Nexin assays on above cells, mean ± SD, (n = 3). by increased phosphorylation of histone H3 (at serine 10) (Figure 5D). In addition, survivin is a reported target of Aurora B-mediated phosphorylation, and it inhibits cas- pase activation thereby mediating cell survival through inhibiting apoptosis [34]. We corroborated these results by showing that radiation induced higher Aurora B activ- ity and correspondingly increased survivin protein expres- sion. However, when cells were additionally treated with CCT137690 to inhibit activity of Aurora B, the protein levels of survivin decreased (Figure 5D). Since survivin is a very important anti-apoptotic protein, the decrease of survivin may explain the synergistic effects between ra- diation and CCT137690. Consistent with this notion, sur- vivin protein expression in SW-48 cells was much lower than that in SW-620 cells (Figure 5E), which may explain the different sensitivities of these cells to radiation. To confirm this point, we managed to over-express survivin in SW48 cells (Figure 5F). As expected, survivin over- expression significantly increases the surviving rates of the cells after radiation (Figure 5G). To further con- firm the central role of Aurora B-survivn signaling path- way in regulating survival upon radiation, we treated SW620 cells with CCT137690 before radiation, lower sur- vivin protein level correlates with lower surviving rate after radiation (Figure 5H and I). In addition, survivin over-expression in drug-treated cells greatly ameliorates radiation induced cell death (Figure 5H and I) further confirmed our hypothesis. by increased phosphorylation of histone H3 (at serine 10) (Figure 5D). In addition, survivin is a reported target of Aurora B-mediated phosphorylation, and it inhibits cas- pase activation thereby mediating cell survival through inhibiting apoptosis [34]. We corroborated these results by showing that radiation induced higher Aurora B activ- ity and correspondingly increased survivin protein expres- sion. However, when cells were additionally treated with CCT137690 to inhibit activity of Aurora B, the protein levels of survivin decreased (Figure 5D). Guava Nexin assay Since survivin is a very important anti-apoptotic protein, the decrease of survivin may explain the synergistic effects between ra- diation and CCT137690. Consistent with this notion, sur- vivin protein expression in SW-48 cells was much lower than that in SW-620 cells (Figure 5E), which may explain the different sensitivities of these cells to radiation. To confirm this point, we managed to over-express survivin in SW48 cells (Figure 5F). As expected, survivin over- expression significantly increases the surviving rates of Discussion Radiotherapy stands a major adjunctive therapeutic op- tion for colorectal cancer management. Although there have been intensive investigations on the optimal regi- men of radiotherapy for this lethal disease, very limited success have been made during the past several decades. CRC is notorious for being refractory to both chemo- therapy and radiotherapy. Thus investigators are particu- larly interested in characterizing novel molecule targets Wu et al. Journal of Experimental & Clinical Cancer Research 2014, 33:13 Page 6 of 9 http://www.jeccr.com/content/33/1/13 Wu et al. Journal of Experimental & Clinical Cancer Research 2014, 33:13 http://www.jeccr.com/content/33/1/13 Page 6 of 9 Figure 4 Low dosage of CCT137690 sensitizes SW620 cells to radiation. A, SW620 cells (with or without drug treatment (100 nM)) were exposed to different dosages of radiation. B and C, representative figures of Guava Nexin assays of cells (with (C) or without (B) drug treatment) exposed to 1 Gy of radiation. D, quantification of Guava Nexin assays on above cells, mean ± SD, (n = 3). Figure 4 Low dosage of CCT137690 sensitizes SW620 cells to radiation. A, SW620 cells (with or without drug treatment (100 nM)) were exposed to different dosages of radiation. B and C, representative figures of Guava Nexin assays of cells (with (C) or without (B) drug treatment) exposed to 1 Gy of radiation. D, quantification of Guava Nexin assays on above cells, mean ± SD, (n = 3). by CCT137690 and to radiation (Figures 1 and 2). How- ever, we found that the combination of Aurora B inhib- ition and radiation exerts synergistic effects on cancer cell growth inhibition. Our results showed that low-dose radi- ation (1 Gy) greatly exaggerates the growth inhibitory ef- fect of CCT137690 on SW-620 cells (Figure 3A), as well as a low-dose of CCT137690 dramatically increases the sensitivity of cells to radiation (Figure 4A). which exert regulatory effects on sensitivity to radioche- motherapy in CRC patients. Positive results from these studies might be clinically important since untoward side effects from radiotherapy or chemotherapy stands as major concerns for clinicians in tumor management and sensitizers of radiochemotherapy may help to reduce dos- age load and associated toxic side effects. In light of this notion, we started to search for poten- tial sensitization targets for radiotherapy of CRC subjects and we found that there is a recent growing interest in the role of Aurora B and cancer biology. Discussion Our observations provide a good proof of concept that both chemotherapy and radiotherapy doses could be greatly lowered by taking the advantages of synergistic effects of those two interventions. This could be trans- lated into the clinic where the expectation is that there would be less adverse side-effects and better patient tolerance at lower doses. These findings are especially important given that CT137690 has a narrow safety margin. In terms of synergistic effect of Aurora B inhibition and radiotherapy sensitivity, a previous study has shown that Aurora B inactivation sensitizes mesothelioma cells [27]. In addition, Aurora B inhibition also potently sup- presses repopulation during fractionated irradiation of human lung cancer cells [28]. In terms of understanding of the mechanism by which inhibiting Aurora B increases radiosensitivity of CRC In the current study, we first show that SW-620 colorec- tal cancer cells are relatively resistant to Aurora B inhibition Page 7 of 9 Wu et al. Journal of Experimental & Clinical Cancer Research 2014, 33:13 http://www.jeccr.com/content/33/1/13 Page 7 of 9 Figure 5 The mechanism underlying the synergic action between CCT137690 and radiation. A and B, relative expression of the indicated genes in SW620 cells treated by control or siRNA of the indicated target, mean ± SD, (n = 3). C, surviving fractions of siRNA transfected cells (from A, B) with or without radiation. D, Western blot analysis of Aurora B, Ser10-phosphorated Histone H3, Histone H3, survivin and GAPDH in cells with indicated treatments (IR means 1 Gy, drug = 100 nM). E, the protein levels of survivin and GAPDH in SW48 and SW620 cells. F, protein levels of survivin and GAPDH in SW48 cells with or without survivin over-expression. G, the surviving fractions of SW48 cells with or without survivin over-expression upon radiation. H, the protein levels of survivin and GAPDH in cells with or without survivin over-expression under Figure 5 The mechanism underlying the synergic action between CCT137690 and radiation. A and B, relative expression of the indicated genes in SW620 cells treated by control or siRNA of the indicated target, mean ± SD, (n = 3). C, surviving fractions of siRNA transfected cells (from A, B) with or without radiation. D, Western blot analysis of Aurora B, Ser10-phosphorated Histone H3, Histone H3, survivin and GAPDH in cells with indicated treatments (IR means 1 Gy, drug = 100 nM). Discussion E, the protein levels of survivin and GAPDH in SW48 and SW620 cells. F, protein levels of survivin and GAPDH in SW48 cells with or without survivin over-expression. G, the surviving fractions of SW48 cells with or without survivin over-expression upon radiation. H, the protein levels of survivin and GAPDH in cells with or without survivin over-expression under indicated treatments (IR =1 Gy, drug = 100 nM). I, the surviving fractions of cells described in H, mean ± SD, (n = 3). Page 8 of 9 Page 8 of 9 cells, we found that Aurora B-survivin pathway may be involved (Figure 5). These findings are consistent with several reports showing the association of Aurora B and survivin in context of CRC. For example, Tuncel et al. reported that nuclear Aurora B and cytoplasmic survivin expression is involved in lymph node metastasis of colo- rectal cancer [16]. Moreover, Aurora-survivin signaling machinery has been implicated in other cancers such as myelodysplasia [35], chronic lymphocytic leukemia [36], head and neck squamous cell cancer [37]. In this regard, we observed that forced-expression of survivin dramatic- ally ameliorates Aurora B-inhibition induced CRC cell death in the context of radiation (Figure 5I). 8. Zhang C, Fang Z, Xiong Y, Li J, Liu L, Li M, Zhang W, Wan J: Copy number increase of aurora kinase A in colorectal cancers: a correlation with tumor progression. Acta Biochim Biophys Sin 2010, 42:834–838. 9. Berdnik D, Knoblich JA: Drosophila Aurora-A is required for centrosome maturation and actin-dependent asymmetric protein localization during mitosis. Curr Biol 2002, 12:640–647. 10. Esposito A, Mancini R, Ettorre G, Garufi C, Saracca E, Arcieri S, Cosimelli M: A combined approach of neoadjuvant chemotherapy and surgery for colorectal liver metastases. J Exp Clin Can Res: CR 2003, 22:197–202. 11. Marumoto T, Honda S, Hara T, Nitta M, Hirota T, Kohmura E, Saya H: Aurora-A kinase maintains the fidelity of early and late mitotic events in HeLa cells. J Biol Chem 2003, 278:51786–51795. 12. Baba Y, Nosho K, Shima K, Irahara N, Kure S, Toyoda S, Kirkner GJ, Goel A, Fuchs CS, Ogino S: Aurora-A expression is independently associated with chromosomal instability in colorectal cancer. Neoplasia 2009, 11:418–425. 13. Authors’ contributions 17. Pohl A, El-Khoueiry A, Yang D, Zhang W, Lurje G, Ning Y, Winder T, Hu-Lieskoven S, Iqbal S, Danenberg KD, et al: Pharmacogenetic profiling of CD133 is associated with response rate (RR) and progression-free survival (PFS) in patients with metastatic colorectal cancer (mCRC), treated with bevacizumab-based chemotherapy. Pharmacogenomics J 2013, 13:173–180. XYW and WTL designed the current study, performed the experiments, collected the data and drafted the manuscript. QHC, CC, ZWC, ZX, WSL provided scientific inputs for study design and technical support for GUAVA assay, construct cloning and radiation treatment. FKL and XQY mentored the whole project, drafted and revised the manuscript. All authors read and approved the final manuscript. 18. Manfredi MG, Ecsedy JA, Chakravarty A, Silverman L, Zhang M, Hoar KM, Stroud SG, Chen W, Shinde V, Huck JJ, et al: Characterization of Alisertib (MLN8237), an investigational small-molecule inhibitor of aurora A kinase using novel in vivo pharmacodynamic assays. Clin Can Res: an Official Journal of the American Association for Cancer Research 2011, 17:7614–7624. Competing interests 16. Tuncel H, Shimamoto F, Kaneko Guangying Qi H, Aoki E, Jikihara H, Nakai S, Takata T, Tatsuka M: Nuclear Aurora B and cytoplasmic Survivin expression is involved in lymph node metastasis of colorectal cancer. Oncol Lett 2012, 3:1109–1114. All authors agreed that there is nothing to disclose for the current study. Funding disclosure statement No current external funding sources for this study, all fundings for the current study are from intramural funding program to Liu FK and Yao XQ. Received: 16 October 2013 Accepted: 20 January 2014 Published: 29 January 2014 21. Carpinelli P, Ceruti R, Giorgini ML, Cappella P, Gianellini L, Croci V, Degrassi A, Texido G, Rocchetti M, Vianello P, et al: PHA-739358, a potent inhibitor of Aurora kinases with a selective target inhibition profile relevant to cancer. Mol Cancer Ther 2007, 6:3158–3168. Discussion Dotan E, Meropol NJ, Zhu F, Zambito F, Bove B, Cai KQ, Godwin AK, Golemis EA, Astsaturov I, Cohen SJ: Relationship of increased aurora kinase A gene copy number, prognosis and response to chemotherapy in patients with metastatic colorectal cancer. Br J Cancer 2012, 106:748–755. Taken together, our results for the first time showed that Aurora B inhibition, via CCT137690, and radiation exposure may play synergistic effects in colorectal cancer death. Taking advantage of this synergistic effect, a lower dose of radiation exposure and/or chemical exposure is required for cancer cell death induction, which may have significant clinical implications for CRC management. 14. Nishida N, Nagasaka T, Kashiwagi K, Boland CR, Goel A: High copy amplification of the Aurora-A gene is associated with chromosomal instability phenotype in human colorectal cancers. Cancer Biol Ther 2007, 6:525–533. 15. Lam AK, Ong K, Ho YH: Aurora kinase expression in colorectal adenocarcinoma: correlations with clinicopathological features, p16 expression, and telomerase activity. Hum Pathol 2008, 39:599–604. Wu et al. Journal of Experimental & Clinical Cancer Research 2014, 33:13 http://www.jeccr.com/content/33/1/13 Author details 1 19. Shimomura T, Hasako S, Nakatsuru Y, Mita T, Ichikawa K, Kodera T, Sakai T, Nambu T, Miyamoto M, Takahashi I, et al: MK-5108, a highly selective Aurora-A kinase inhibitor, shows antitumor activity alone and in combination with docetaxel. Mol Cancer Ther 2010, 9:157–166. 1Department of Surgical Oncology, Affiliated Hospital of Nanjing University of Traditional Chinese Medicine, 155 Guangzhou Road, Nanjing 210029, China. 2Department of Surgery, Ruijin Hospital, Shanghai Jiaotong University, Shanghai Institute of Digestive Surgery, Shanghai 200025, China. 1Department of Surgical Oncology, Affiliated Hospital of Nanjing University of Traditional Chinese Medicine, 155 Guangzhou Road, Nanjing 210029, China. 2Department of Surgery, Ruijin Hospital, Shanghai Jiaotong University, Shanghai Institute of Digestive Surgery, Shanghai 200025, China. 20. Harrington EA, Bebbington D, Moore J, Rasmussen RK, Ajose-Adeogun AO, Nakayama T, Graham JA, Demur C, Hercend T, Diu-Hercend A, et al: VX-680, a potent and selective small-molecule inhibitor of the Aurora kinases, suppresses tumor growth in vivo. Nat Med 2004, 10:262–267. Received: 16 October 2013 Accepted: 20 January 2014 Published: 29 January 2014 References Page 9 of 9 Page 9 of 9 Wu et al. Journal of Experimental & Clinical Cancer Research 2014, 33:13 http://www.jeccr.com/content/33/1/13 migration and decreases radiosensitivity in cancer cells. Cancer Res 2007, 67:10436–10444. migration and decreases radiosensitivity in cancer cells. Cancer Res 2007, 67:10436–10444. 26. Venkataraman S, Alimova I, Tello T, Harris PS, Knipstein JA, Donson AM, Foreman NK, Liu AK, Vibhakar R: Targeting Aurora Kinase A enhances radiation sensitivity of atypical teratoid rhabdoid tumor cells. J Neuro Oncol 2012, 107:517–526. 27. Kim KW, Mutter RW, Willey CD, Subhawong TK, Shinohara ET, Albert JM, Ling G, Cao C, Gi YJ, Lu B: Inhibition of survivin and aurora B kinase sensitizes mesothelioma cells by enhancing mitotic arrests. Int J Radiat Oncol Biol Phys 2007, 67:1519–1525. 28. Sak A, Stuschke M, Groneberg M, Kubler D, Pottgen C, Eberhardt WE: Inhibiting the aurora B kinase potently suppresses repopulation during fractionated irradiation of human lung cancer cell lines. Int J Radiat Oncol Biol Phys 2012, 84:492–499. 29. Bavetsias V, Large JM, Sun C, Bouloc N, Kosmopoulou M, Matteucci M, Wilsher NE, Martins V, Reynisson J, Atrash B, et al: Imidazo[4,5-b]pyridine derivatives as inhibitors of Aurora kinases: lead optimization studies toward the identification of an orally bioavailable preclinical development candidate. J Med Chem 2010, 53:5213–5228. 30. Faisal A, Vaughan L, Bavetsias V, Sun C, Atrash B, Avery S, Jamin Y, Robinson SP, Workman P, Blagg J, et al: The aurora kinase inhibitor CCT137690 downregulates MYCN and sensitizes MYCN-amplified neuroblastoma in vivo. Mol Cancer Ther 2011, 10:2115–2123. 31. Moore AS, Faisal A, de Castro Gonzalez D, Bavetsias V, Sun C, Atrash B, Valenti M, de Haven Brandon A, Avery S, Mair D, et al: Selective FLT3 inhibition of FLT3-ITD+ acute myeloid leukaemia resulting in secondary D835Y mutation: a model for emerging clinical resistance patterns. Leukemia 2012, 26:1462–1470. 32. Krishnan S, Janjan NA, Skibber JM, Rodriguez-Bigas MA, Wolff RA, Das P, Delclos ME, Chang GJ, Hoff PM, Eng C, et al: Phase II study of capecitabine (Xeloda) and concomitant boost radiotherapy in patients with locally advanced rectal cancer. Int J Radiat Oncol Biol Phys 2006, 66:762–771. 33. Longley DB, Allen WL, Johnston PG: Drug resistance, predictive markers and pharmacogenomics in colorectal cancer. Biochim Biophys Acta 2006, 1766:184–196. 34. Wu et al. Journal of Experimental & Clinical Cancer Research 2014, 33:13 http://www.jeccr.com/content/33/1/13 References 1. Kamangar F, Dores GM, Anderson WF: Patterns of cancer incidence, mortality, and prevalence across five continents: defining priorities to reduce cancer disparities in different geographic regions of the world. J Clin Oncol 2006, 24:2137–2150. 22. Wilkinson RW, Odedra R, Heaton SP, Wedge SR, Keen NJ, Crafter C, Foster JR, Brady MC, Bigley A, Brown E, et al: AZD1152, a selective inhibitor of Aurora B kinase, inhibits human tumor xenograft growth by inducing apoptosis. Clin Can Res: An Official Journal of the American Association for Cancer Research 2007, 13:3682–3688. 2. Jemal A, Bray F, Center MM, Ferlay J, Ward E, Forman D: Global cancer statistics. CA Cancer J Clin 2011, 61:69–90. 2. Jemal A, Bray F, Center MM, Ferlay J, Ward E, Forman D: Global cancer statistics. CA Cancer J Clin 2011, 61:69–90. 3. Tsujii M: Search for novel target molecules for the effective treatment or prevention of colorectal cancer. Digestion 2012, 85:99–102. 3. Tsujii M: Search for novel target molecules for the effective treatment or prevention of colorectal cancer. Digestion 2012, 85:99–102. 23. Cammareri P, Scopelliti A, Todaro M, Eterno V, Francescangeli F, Moyer MP, Agrusa A, Dieli F, Zeuner A, Stassi G: Aurora-a is essential for the tumorigenic capacity and chemoresistance of colorectal cancer stem cells. Cancer Res 2010, 70:4655–4665. 4. Lu JB, Sun XB, Dai DX, Zhu SK, Chang QL, Liu SZ, Duan WJ: Epidemiology of gastroenterologic cancer in Henan Province, China. World J Gastroenterol: WJG 2003, 9:2400–2403. 5. Yang L, Parkin DM, Li LD, Chen YD, Bray F: Estimation and projection of the national profile of cancer mortality in China: 1991-2005. Br J Cancer 2004, 90:2157–2166. 24. Wan XB, Fan XJ, Huang PY, Dong D, Zhang Y, Chen MY, Xiang J, Xu J, Liu L, Zhou WH, et al: Aurora-A activation, correlated with hypoxia-inducible factor-1alpha, promotes radiochemoresistance and predicts poor outcome for nasopharyngeal carcinoma. Cancer Sci 2012, 103:1586–1594. 6. Sung JJ, Lau JY, Goh KL, Leung WK, Asia Pacific Working Group on Colorectal C: Increasing incidence of colorectal cancer in Asia: implications for screening. Lancet Oncol 2005, 6:871–876. 25. Guan Z, Wang XR, Zhu XF, Huang XF, Xu J, Wang LH, Wan XB, Long ZJ, Liu JN, Feng GK, et al: Aurora-A, a negative prognostic marker, increases 7. Yee YK, Tan VP, Chan P, Hung IF, Pang R, Wong BC: Epidemiology of colorectal cancer in Asia. J Gastroenterol Hepatol 2009, 24:1810–1816. References Yoon MJ, Park SS, Kang YJ, Kim IY, Lee JA, Lee JS, Kim EG, Lee CW, Choi KS: Aurora B confers cancer cell resistance to TRAIL-induced apoptosis via phosphorylation of survivin. Carcinogenesis 2012, 33:492–500. 35. Yoshida A, Zokumasu K, Wano Y, Yamauchi T, Imamura S, Takagi K, Kishi S, Urasaki Y, Tohyama K, Ueda T: Marked upregulation of Survivin and Aurora-B kinase is associated with disease progression in the myelodysplastic syndromes. Haematologica 2012, 97:1372–1379. 36. de Paula Careta F, Gobessi S, Panepucci RA, Bojnik E, de Oliveira Morato F, Mazza Matos D, Falcao RP, Laurenti L, Zago MA, Efremov DG: The Aurora A and B kinases are up-regulated in bone marrow-derived chronic lymphocytic leukemia cells and represent potential therapeutic targets. Haematologica 2012, 97:1246–1254. 37. Erpolat OP, Gocun PU, Akmansu M, Karakus E, Akyol G: High expression of nuclear survivin and Aurora B predicts poor overall survival in patients with head and neck squamous cell cancer. Strahlenther Onkol 2012, 188:248–254. doi:10.1186/1756-9966-33-13 Cite this article as: Wu et al.: Inhibition of Aurora B by CCT137690 sensitizes colorectal cells to radiotherapy. Journal of Experimental & Clinical Cancer Research 2014 33:13. 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Thirty years of CMV seroprevalence—a longitudinal analysis in a German university hospital
European journal of clinical microbiology & infectious diseases
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Abstract Human cytomegalovirus (CMV) is a significant cause of morbidity and mortality in patient groups at risk. We have previously shown that the anti-CMV IgG seroprevalence in an urban region of Germany has changed over the last decades. Overall, a decline from 63.7 to 57.25% had been observed between 1988–1997 and 1998–2008 (p < 0,001). Here, we continuously follow the trends to the most recent decade 2009 to 2018. In a retrospective analysis, we determined the seroprevalence of CMV IgG antibodies in our patient cohort, stratified by gender and selected groups at risk (e.g., patients with HIV infection; women of childbearing age). The overall prevalence of anti-CMV IgG non-significantly declined further from 57.25% in 1998–2008 to 56.48% in 2009–2018 (p = 0.881). Looking at gender differences, overall CMV seroprevalence in males declined to 52.82% (from 55.54% in 1998–2008; p = 0.0254), while it non-significantly increased in females to 59.80%. The high seroprevalence in patients with a known HIV infection further increased from 87.46% in 1998–2008 to 92.93% in the current period (p = 0.9999). In women of childbearing age, no significant changes over the last three decades could be observed. The CMV seroprevalence in oncological patients was determined to be 60.64%. Overall, the former significant decline of CMV seroprevalence between the decades 1988–1997 and 1998–2008 in this urban region of Germany slowed down to a non-significant decrease of 0.77% (1998– 2008 vs. 2009–2018). This might be an indicator that CMV seroprevalence has reached a plateau. Keywords Cytomegalovirus (CMV) . Seroprevalence . Anti-CMV IgG . Human immunodeficiency virus (HIV) . Congenital CMVinfection . CMVepidemiology Keywords Cytomegalovirus (CMV) . Seroprevalence . Anti-CMV IgG . Human immunodeficiency virus (HIV) . Congenital CMVinfection . CMVepidemiology Thirty years of CMV seroprevalence—a longitudinal analysis in a German university hospital Received: 8 November 2019 /Accepted: 12 January 2020 # The Author(s) 2020 1 Institute for Medical Virology, University Hospital, Goethe University Frankfurt am Main, Paul-Ehrlich-Straße 40, 60496 Frankfurt am Main, Germany European Journal of Clinical Microbiology & Infectious Diseases https://doi.org/10.1007/s10096-020-03814-x European Journal of Clinical Microbiology & Infectious Diseases https://doi.org/10.1007/s10096-020-03814-x ORIGINAL ARTICLE * Holger F. Rabenau rabenau@em.uni-frankfurt.de * Sebastian Hoehl sebastian.hoehl@kgu.de Patient collective Due to the possibility of maternal antibody detection, infants below the age of 1 year were excluded. Of each patient, only the first CMV IgG test in the time period was considered, and seropositivity defined as a positive result in the anti-CMV antibody IgG assay. Patients with an unspecific or borderline reactivity on the CMV IgG test were excluded. Group, age- and gender-dependent analysis was performed. The mathe- matical median of the positive test results was calculated. The comparative changes of CMV seroprevalence among the patients of the urban University Hospital of Frankfurt, Germany, over the period of 1988 to 1997 and 1998 to 2008 have previously been assessed. An overall decline in CMV seroprevalence among its pa- tients without a known HIV infection from the first to the second decade, decreasing from 63.70% to 57.25%, was observed. This decrease in CMV seroprevalence has also been observed in other studies in Germany [13, 16] and, in some groups, in Spain [14], but not in the USA [12]. The decrease has also been observed in bone marrow donors in Germany [16]. In the former study conducted in Frankfurt, females had a slightly higher CMV seroprevalence than men (63.83% com- pared with 65.54% in 1988–1997 and 58.73% compared with 55.54% in 1998–2008). Patients with a known HIV infection had a significantly higher CMV seroprev- alence (in females, 83.17% in 1988–1997 and 87.80% in 1998–2008, in males, 88.76% in 1988–1997 and 87.32% in 1998–2008) [13]. Patients with a confirmed HIV infection were analyzed separately to avoid bias by a higher-than-average CMV sero- prevalence within this group and overrepresentation in our patient cohort. Positive HIV status was defined as a positive result in a 4th generation antibody/antigen-HIV screening test followed by a positive confirmation test by HIV immunoblot and/or HIV-PCR in the studied time period. The data of all three decades was revisited to determine the CMV IgG seroprevalence of women of childbearing age. We chose samples of women of childbearing age sent in by our Department of Obstetrics and Gynecology, as testing of those samples was presumed to be indicated by pregnancy or birth. We compared the CMV seroprevalence in this group between the three decades, and formed four age groups for comparative analysis. Material and methods Insight into the dynamics of CMV epidemiology is there- fore highly relevant for diverse, vulnerable groups of patients. We conducted a retrospective analysis of the data routinely acquired during patient care at the University Hospital of Frankfurt. All results of anti-CMV IgG antibody tests from our Institute of Medical Virology in the time frame January 1, 2009, and December 31, 2018, were analyzed. The University Hospital of Frankfurt is the largest hospital and a maximum care provider in Germany’s fifth largest city. It treats about 49,000 in-patients and 229,000 out-patients a year. Different areas of the world can be divided in low (50 to 70%) and high seroprevalence settings (> 70%) [8]. It is usu- ally higher in low income countries [9–14]. A limited number of studies have focused on the CMV seroprevalence in Germany. In children and adolescents in Germany, a study of the CMV IgG seroprevalence (KiGGS study, 2003–2006) found a range between 21.4% in boys at 1–2 years of age and 33.5% in girls at 14–17 years of age. CMV seroprevalence increased with age in both genders. Risk factors for higher seroprevalence included migration background, place of birth other than Germany, having attended daycare, and having younger siblings [15]. In a study in the adult population of Germany, sera collected throughout Germany in 1998, pub- lished 2018, the overall CMV seroprevalence was 56.7% and also increased with age. It was higher in females (62.3%) than in males (51.0%). Total seroprevalence in women of child- bearing age (18 to 45 years of age) was 51.7%. The study also identified risk factors associated with seropositivity, with country of birth and age being the strongest independent fac- tors [11]. All anti-CMV IgG tests (Enzygnost anti-CMV IgG, Dade Behring, Marburg, Germany) were performed on the Behring ELISA Processor BEP 2000, the results were recorded semi- quantitatively as arbitrary units per milliliter (AU/mL). The test results of the decade 2009–2018 were compared with the two decades of the former study (1988–1997; 1998– 2008) [13] in which the same diagnostic test had been used. Introduction 2 cases per 1000 pregnant women in Germany [5], making it the most common infectious cause of birth defects. Permanent sequelae include sensorineural hearing loss (SNHL), micro- cephaly, seizures, neurologic deficits, and retinitis. Counseling about hygiene can lower the risk of anti-CMV IgG negative women to get infected during pregnancy [5, 6]. The rate of SNHL appears to be similar for children born after primary and non-primary maternal CMV infection, but seems to be more severe in the primary maternal infection group [7]. Primary CMV infection in immunocompetent hosts may be asymptomatic, or may cause mostly mild, self-limiting disease with fever, fatigue, headaches, and myalgia [1, 2]. After pri- mary infection, the virus remains latent. Infants and toddlers are an import source of infection, as they can shed the virus by urine or saliva for months or even years after infection [3, 4]. Primary infection, reactivation, or reinfection shortly be- fore or during pregnancy can result in congenital CMV infec- tion, which is estimated to lead to permanent disability in 1 to In immunocompromised hosts, CMV poses a major burden of disease. People living with HIV/AIDS usually have a high rate of CMV seropositivity. Therefore, the risk of primary CMV infection is low, but reactivation or reinfection as an opportunistic infection most commonly manifests as retinitis, colitis or esophagitis, hepatitis, encephalitis, myeloradiculopathy, or pneumonia. Otherwise immunocom- promised hosts, such as oncological patients and solid organ or stem cell transplant recipients, are additional groups affect- ed by increased risk of morbidity and mortality associated with CMV. Eur J Clin Microbiol Infect Dis CMV seroprevalence by gender Samples of a total of 31,401 patients above the age of 1 year had been tested for anti-CMV IgG antibodies in the years between 2009 and 2018. A total of 258 patients who had borderline or unspecific test results were excluded, leaving 31,143 patients with an unambiguous result. The overall CMV seroprevalence in the most recent decade 2009–2018 was significantly higher in females (59.80%, n = 15,420) than in males (50.82%, n = 13,983, p < 0.0001). During the studied period of 30 years, CMV seroprevalence decreased in both sexes. However, from the time period of 1998–2008 to 2009–2018, there was a non-significant in- crease in females (p = 0.0811) (Fig. 2), and a significant de- crease of 2.72% in males (p = 0.0254). Patient collective Patients younger than 16 or older than 45 years of age were excluded from age-dependent analysis, since there were a relatively low number of those samples, and therefore, CMV seroprevalence could not be determined with confi- dence. In addition, we determined the accumulated CMV se- roprevalence of patients whose samples were sent in from an oncological department or ward. We stratified by pediatric and adult patients, defined by patient age. All patients younger than 18 years of age were considered to be pediatric. In the current study, we set out to determine whether the decline continued to the most recent decade, and especially observed the changes over in time in two selected groups of vulnerable patients, the developing fetus, examined in proxy by the status of their pregnant mothers, as well as people living with HIV/AIDS. As another important group affected by CMV disease, we also looked at oncological patients. We determined the accu- mulated CMV seroprevalence of those patients whose sam- ples were sent in from oncology wards, stratified by pediatric and adult patients. Statistical testing was performed using BiAS® for Windows (version 11.10, epsilon-Verlag, Hochheim, Eur J Clin Microbiol Infect Dis older,” respectively (p values < 0.0001) (Fig. 1). CMV sero- prevalence throughout all age groups declined significantly when compared with the decade 1988–1997. A sustained de- crease spanning all three decades can be observed in the group of 1 to 9 year olds, and in all age groups 40 years and older (Fig. 1). Germany, 2019), including the calculation of the 95% confi- dence intervals. P values were calculated using the two-tailed, not Yates rectified chi-squared test. A p value of ≤0.05 was defined as statistically significant. Germany, 2019), including the calculation of the 95% confi- dence intervals. P values were calculated using the two-tailed, not Yates rectified chi-squared test. A p value of ≤0.05 was defined as statistically significant. Figures were created using GraphPad Prism 6. Women of childbearing age declining up to the age group 31 to 35 years of age, followed by a continuous increase with progressing age (Fig. 5). The decrease from 16 to 20 years of age (76.22%) to 31 to 35 years of age (60.13%) is statistically highly significant (p < 0.0001). There was no major change in the overall CMV seropreva- lence of women of childbearing age presenting to the Department of Gynecology and Obstetrics during the last three decades. A slight increase from 64.18% (n = 3395) in the decade 1988–1997 to 65.95% (n = 2429) in 2009–2018 cannot be asserted with confidence (p = 0.1627) (Fig. 4). All patients after exclusion of those known to be HIV positive (p ) Looking at the most recent decade only, CMV seropreva- lence is higher in females in all age groups, however, not statistically significant in the age groups 1 to 9 and 10 to 19 years of age (p = 0.1046 and p = 0.2503, respectively), while significant in all other age groups. In the group 20 to 29 years of age, there is a sharp increase in females of 10.69% and a decline in males, resulting in a large gap between the genders of 17.09% (39.75% in males, 56.84% in females). In males, CMV seroprevalence increases sharply between the age groups 20 to 29 and 30 to 39 years of age, by 10.58%. Finally, CMV seroprevalence in both sexes merge toward a linear increase, with seroprevalence in females about 7.5% higher than in men (Fig. 3). The overall CMV IgG seroprevalence in the cohort in the decade 2009–2018, after exclusion of 1740 patients with known HIV infection, was 56.48% (n = 29,403). The median value in the HIV-negative population was 1400 AU/mL. When comparing anti-CMV IgG seropositivity to the data of the former decades, a continuous decline is visible: from 63.70% (n = 29,374) in the decade 1988–1997 and 57.27% (n = 20,397) in the decade 1998–2008. While the slight overall decrease from the previous to the most recent decade (1998–2008 to 2009–2018) of 0.77% was not statistically significant (p = 0.0881), a significant decrease can confidently be assessed when looking at the age groups “20 to 29,” “40 to 49,” “50 to 59,” and “60 years of age and Fig. 1 CMV IgG seroprevalence by age group and decade. Patients with a known HIV infection were excluded in all decades. *Data previously published by our group (Lübeck et al.) [13]; y/o, years old Fig. 1 CMV IgG seroprevalence by age group and decade. Patients with a known HIV infection were excluded in all decades. *Data previously published by our group (Lübeck et al.) [13]; y/o, years old Eur J Clin Microbiol Infect Dis Women of childbearing age declining up to the age group 31 to 35 years of age followed Fig. 2 CMV IgG seroprevalence by gender and decade. *Data previously published by our group (Lübeck et al.) [13] Fig. 2 CMV IgG seroprevalence by gender and decade. *Data previously published by our group (Lübeck et al.) [13] CMV seroprevalence in HIV-positive patients In our cohort, 1740 patients had a known HIV infection. Of those, 1617 had a positive anti-CMV IgG test result; the sero- prevalence was 92.93%. The median of all positive samples was 2409 AU/mL. Compared with the data of the two previous A look at the distribution between different age groups spanning all three decades reveals the highest seroprevalence rate in the youngest age group (16 to 20 years of age), that is Fig. 3 CMV IgG seroprevalence 2009–2018 by age group [13] Fig. 3 CMV IgG seroprevalence 2009–2018 by age group [13] Eur J Clin Microbiol Infect Dis Fig. 4 CMV IgG seroprevalence of women of childbearing age, by decade Eur J Clin Microbiol Infect Dis Fig. 4 CMV IgG seroprevalence of women of childbearing age, by decade intervals overlapped. When compared with 1988–1997, how- ever, the increase is highly significant (p < 0.0001) (Fig. 6). decades, we could observe an increase in seropositivity of 5.47%, which is not statistically significant (p = 0.9999). A significant difference in CMV seroprevalence between males and females with a known HIV infection had not been observed in the decades of 1988–1997 and 1998–2008. In the most recent decade, however, the CMV seroprevalence of females with a known HIV infection was higher than in males When looking at the genders separately, the largest increase was in females with a known HIV infection, with an increase of 6.81% when compared with 1998–2008, and 11.44% when compared with 1988–1997. Between the former two decades, the increase had little confidence, since the 95% confidence Fig. 5 CMV IgG seroprevalence 1988–2019 by age group from women of childbearing age Eur J Clin Microbiol Infect Dis Fig. 6 CMV IgG seroprevalence by gender and decade of patients with known HIV infection. *Data previously published by our group (Lübeck et al) [13] 29 years of age and all groups above the age of 40 years. In our youngest patients, below the age of 20 years, and in the age group 30–39 years, however, the trend halted or even re- versed. In the youngest patients, this might be associated with more children below the age of 3 years attending daycare, where the exposure to potentially infectious toddlers as a source of infection is increased, a known factor associated with CMV seropositivity in Germany [15]. Fig. 6 CMV IgG seroprevalence by gender and decade of patients with known HIV infection. *Data previously published by our group (Lübeck et al) [13] CMV seroprevalence in oncological patients In patients whose samples were sent in from oncological de- partments, we determined a combined CMV seroprevalence of 60.64% (n = 2091). It was lower in the pediatric population, where it was 51.60% (n = 219), and higher in the adult popu- lation (61.70%, n = 1872). CMV seroprevalence in HIV-positive patients Notably, from 2006 to 2017, the percentage of children below the age of 3 years attending day care in Germany increased from 13.6 to 33.1% [22]. Another factor offsetting the decreasing trend in CMV prevalence might be associated with increased mi- gration from non-EU countries, especially to the urban centers of Germany. This could most markedly affect the age group with the largest number of patients: 30 to 39 year olds saw an increase of 1.28% in CMV seroprevalence (Fig. 3). Non-EU nationals currently make up 22.08% of all 25- to 44-year olds living in Frankfurt. Non-EU nationals living in Frankfurt largely stem from regions with high CMV seroprevalence, most markedly Turkey [23], where CMV seroprevalence is reported to be between 94.9% and 96.4% in pregnant women [19, 24]. Especially in children, migration background is well characterized as a factor associated with a higher CMV sero- prevalence [15]. It remains unclear if the overall declining trend in CMV seroprevalence possibly continued in the sub- population of patients without a migration background, as we did not have information on the ethnicity of our patients. (94.61% and 92.36%, respectively), but with little confidence (p = 0.1099). High CMV seroprevalence in patients with a known HIV infection could be observed in all age groups with little vari- ation. In the analysis by sex and age in the group of patients with a known HIV infection, the sample size was too small to confidently identify differences. Discussion In this study, we present an overview of the changes in CMV IgG seroprevalence of the patients of the urban University Hospital of Frankfurt over a time period of 30 years. In the most recent decade (2009 to 2018), the overall CMV seroprevalence in patients without a known HIVinfection was 56.48%. This number is within the wide range of the previ- ously published data for population groups in Europe of 30.4 to 89.7%. [9, 11, 13–19]. The slight decrease of 0.77% from the previous decade (1998 to 2008) was not statistically sig- nificant (p = 0.0881). Therefore, the decline in overall CMV seroprevalence in Germany, that has also been observed in other studies [16], appears to be slowing down or even halting. Changes in lifestyle, such as well-documented tendency to- ward smaller households [20] in Germany, with fewer young children as possible sources of infection [21] during the last decades, may have been a driver behind the decreasing trend, which was continuously observed in the age group of 20 to In the most recent decade (2009–2018), women had a sig- nificantly higher CMV seroprevalence than men (59.80 versus 50.82%), a surplus of 8.98%. Other studies also observed a higher seroprevalence in females [11, 13, 16]. Even though this phenomenon has been observed before, it is not entirely understood why women have a higher CMV seroprevalence. While social factors like earlier and more extensive involve- ment in the care of potentially infectious toddlers and infant might be contributing, this would not explain the higher CMV Eur J Clin Microbiol Infect Dis seroprevalence in females of all age groups. A sharp increase in CMV seroprevalence occurs in females between the age groups 10 to 19 and 20 to 29 years of age, and in males between the age groups 20 to 29 and 30 to 39 years of age (Fig. 4). The delayed increase in men, as well as the higher overall prevalence in women after puberty, might be attributed to CMV, like other sexually transmitted infections, being sex- ually transmitted at a higher rate from infectious men to sus- ceptible women than from infectious women to susceptible men [25]. all combined oncological patients. The main goal of this study was the description of changes in CMV seroprevalence over time. Discussion In the case of oncological patients, however, we cannot compare this number to the previous decades, as the structures of our University Hospital as well as the data accompanying the samples has changed in the last 30 years, and no congruent groups could be defined. Patients could also not be divided into further subgroups of interest, such as solid organ or stem cell recipients, since such data was not easily attained. This is an area that should be further examined in future studies. Other limitations of our study include our hospital cohort setting in an urban region of Germany, which is not represen- tative of the general population. We also cannot be sure that the sent-in practices for CMVassays in our university hospital did not change during the examined period of 30 years, and influenced the comparability of the studies. During the last three decades, there was an increased awareness of the dan- gers of primary CMV infection during pregnancy, and there- fore, more testing occurred in pregnant women, distorting the overall numbers by over-representing this group. In women of childbearing age presenting to the Department of Obstetrics and Gynecology, we observed a CMV seroprevalence of 65.95%, which is significantly higher than the overall rate of 59.80%. There was no significant change during the last 30 years (Fig. 4). Other studies in women of childbearing age in Germany reported lower rates in pregnant women, ranging from 34% in a small group of 34 pregnant women from all over Germany [11] to 46–52%, with data from a central German University Hospital [11, 18]. Stratified by age group and spanning over three decades, we could see the highest CMV seroprevalence in young women (76.22% in the age group 16 to 20 years of age) that was declin- ing up to the group 31 to 35 years of age. This phenomenon has previously been observed in studies from 1991 (Friese et al.) and 2011 (Enders et al.) [16, 17], and might be due to women with lower socioeconomic status [26] as well as women with migra- tion background from non-EU countries [27] tending to give birth to their first child earlier in life, both factors associated with higher CMV prevalence [16, 18, 28]. In the following age groups, CMV seroprevalence rises continuously (Fig. 4). Funding Information Open Access funding provided by Projekt DEAL. Funding Information Open Access funding provided by Projekt DEAL. Discussion The strength of this study lies in the large number of pa- tients (31,401 in the decade 2009–2018), and the good com- parability of the test results, as the same diagnostic test had been applied over the last three decades. Overall, the former significant decline of CMV seropreva- lence between the decades 1988–1997 and 1998–2008 in this urban region of Germany slowed down to a non-significant decrease of 0.77% (1998–2008 vs. 2009–2018). This might be an indicator that the dynamic of the CMV seroprevalence has reached a plateau. It remains unclear whether the herein described changes in CMV immunity over time have a tangi- ble impact on the incidence of CMV disease in groups at risk. In women of childbearing age, there was no significant change in CMV seropositivity in the last three decades, and therefore, no change in the proportion of women who are at risk of primary CMV infection during pregnancy. In patients with a known HIV infection, a further increase in the already high CMV seroprevalence could be observed, most strikingly in women, who had a CMV seroprevalence of 94.61%, an increase of 6.81% when compared with the former decade. In males, CMV seroprevalence also increased, but not quite as much, and was 92.36%. Especially in women with a known HIV infection, this trend might be associated with migration from Sub-Saharan Africa after 2013 [29], where CMV seropositivity in asymptomatic, HIV-positive patients approaches 100% [10]. It is noteworthy that the median value of all positive samples was higher in the group of patients that are known to be HIV positive, with a value of 2409 AU/mL, as compared with 1400 AU/mL in the HIV-negative group. It needs to be taken into account that this does not represent the mathematical mean, which could not be calculated due to a recorded upper limit in the AU/mL value, and it is unclear if this less than twofold difference represents a clinically rele- vant gap. In patients that could be identified as oncological, a CMV seroprevalence of 60.64% (n = 2091) was determined in the current decade. In pediatric patients, it was 51.60%, and 61.70% in adult patients. The excess from the overall sero- prevalence of 56.48% in the HIV-negative cohort is statisti- cally significant (p = 0.0002), but there are no numbers avail- able in the literature to which we could compare this result of References 17. Friese K, Beichert M, Hof H et al (1991) Untersuchung zur Häufigkeit konnataler Infektionen (Incidence of congenital infec- tions). Geburtshilfe Frauenheilkd 51(11):890–896. https://doi.org/ 10.1055/s-2008-1026231 1. Nolan N, Halai U-A, Regunath H et al (2017) Primary cytomega- lovirus infection in immunocompetent adults in the United States— a case series. IDCases 10:123–126. https://doi.org/10.1016/j.idcr. 2017.10.008 18. Rütten H, Rissmann A, Brett B et al (2017) Congenital cytomega- lovirus infection in Central Germany: an underestimated risk. Arch Gynecol Obstet 296(2):231–240. https://doi.org/10.1007/s00404- 017-4435-4 2. Just-Nübling G, Korn S, Ludwig B et al (2003) Primary cytomeg- alovirus infection in an outpatient setting—laboratory markers and clinical aspects. Infection 31(5):318–323. https://doi.org/10.1007/ s15010-003-3129-y 19. Tamer GS, Dundar D, Caliskan E (2009) Seroprevalence of Toxoplasma gondii, rubella and cytomegalovirus among pregnant women in western region of Turkey. CIM 32(1):43. https://doi.org/ 10.25011/cim.v32i1.5086 3. Cannon MJ, Stowell JD, Clark R et al (2014) Repeated measures study of weekly and daily cytomegalovirus shedding patterns in saliva and urine of healthy cytomegalovirus-seropositive children. BMC Infect Dis 14:569. https://doi.org/10.1186/s12879-014-0569- 1 20. Bundesinstitut für Bevölkerungsforschung (2018) Durchschnittliche Größe der Privathaushalte nach Bundesländern, 1991, 2001, 2011 und 2016. https://www.bib. bund.de/DE/Fakten/Fakt/Bilder/L85-Haushaltsgroesse- Bundeslaender-ab-1991.html?nn=9994282. Accessed 20 Aug 2019 4. Revello MG, Campanini G, Piralla A et al (2008) Molecular epide- miology of primary human cytomegalovirus infection in pregnant women and their families. J Med Virol 80(8):1415–1425. https:// doi.org/10.1002/jmv.21243 5. Buxmann H, Hamprecht K, Meyer-Wittkopf M et al (2017) Primary human cytomegalovirus (HCMV) infection in pregnancy. Dtsch Arztebl Int 114(4):45–52. https://doi.org/10.3238/arztebl. 2017.0045 21. Bundesinstitut für Bevölkerungsforschung (2018) Privathaushalte mit minderjährigen Kindern* in Deutschland nach Kinderzahl, 1991 bis 2016. https://www.bib.bund.de/DE/Fakten/Fakt/L67- Privathaushalte-Kinderzahl-ab-1991.html. Accessed 20 Aug 2019 6. Vauloup-Fellous C, Picone O, Cordier A-G et al (2009) Does hy- giene counseling have an impact on the rate of CMV primary in- fection during pregnancy? Results of a 3-year prospective study in a French hospital. J Clin Virol 46(Suppl 4):S49–S53. https://doi.org/ 10.1016/j.jcv.2009.09.003 22. Bundesministerium für Familie, Senioren, Frauen und Jugend (ed) (2018) Kindertagesbetreuung kompakt.: Ausbaustand und Bedarf 2017. Ausgabe 03 23. Stadt Frankfurt am Main, Bürgeramt Statistik und Wahlen statistik.aktuell. Ausgabe 02/2019 7. Ross SA, Fowler KB, Ashrith G et al (2006) Hearing loss in chil- dren with congenital cytomegalovirus infection born to mothers with preexisting immunity. J Pediatr 148(3):332–336. https://doi. org/10.1016/j.jpeds.2005.09.003 24. Ocak S, Zeteroglu S, Ozer C et al (2007) Seroprevalence of Toxoplasma gondii, rubella and cytomegalovirus among pregnant women in southern Turkey. Scand J Infect Dis 39(3):231–234. https://doi.org/10.1080/00365540600978880 8. Compliance with ethical standards Conflict of interest The authors declare that they have no conflict of interest. Ethical approval This study was permitted by a vote of our University Hospital’s ethics board. Informed consent Our study was based on the retrospective analysis of anonymous patient data only. Informed consent was not obtainable, and not required by vote of our University Hospital’s ethics board. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adap- tation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, Eur J Clin Microbiol Infect Dis 14. de Ory F, Ramírez R, García Comas L et al (2004) Is there a change in cytomegalovirus seroepidemiology in Spain? Eur J Epidemiol 19(1):85–89 provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated oth- erwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. 15. Voigt S, Schaffrath Rosario A, Mankertz A (2015) Cytomegalovirus seroprevalence among children and adolescents in Germany: data from the German health interview and examina- tion survey for children and adolescents (KiGGS), 2003–2006. Open Forum Infect Dis 3(1). https://doi.org/10.1093/ofid/ofv193 16. Enders G, Daiminger A, Lindemann L et al (2012) Cytomegalovirus (CMV) seroprevalence in pregnant women, bone marrow donors and adolescents in Germany, 1996–2010. Med Microbiol Immunol 201(3):303–309. https://doi.org/10.1007/ s00430-012-0232-7 References Manicklal S, Emery VC, Lazzarotto T et al (2013) The “silent” global burden of congenital cytomegalovirus. Clin Microbiol Rev 26(1):86–102. https://doi.org/10.1128/CMR.00062-12 25. Staras SAS, Flanders WD, Dollard SC et al (2008) Influence of sexual activity on cytomegalovirus seroprevalence in the United States, 1988–1994. Sex Transm Dis 35(5):472–479. https://doi. org/10.1097/OLQ.0b013e3181644b70 9. Ludwig A, Hengel H (2009) Epidemiological impact and disease burden of congenital cytomegalovirus infection in Europe. Euro Surveill 14(9):26–32 26. Statistisches Landesamt Baden-Württemberg (2015) Pressemitteilung 304 / 2015, Stuttgart 10. Bates M, Brantsaeter AB (2016) Human cytomegalovirus (CMV) in Africa: a neglected but important pathogen. J Virus Erad 2(3): 136–142 27. Bundesministerium für Familie, Senioren, Frauen und Jugend (ed) (2016) Familien mit Migrationshintergrund: Analysen zur Lebenssituation, Erwerbsbeteiligung und Vereinbarkeit von Familie und Beruf. 2. aktualisierte und überarbeitete Auflage 11. Lachmann R, Loenenbach A, Waterboer T et al (2018) Cytomegalovirus (CMV) seroprevalence in the adult population of Germany. PLoS One 13(7). https://doi.org/10.1371/journal. pone.0200267 28. Basha J, Iwasenko JM, Robertson P et al (2014) Congenital cyto- megalovirus infection is associated with high maternal socio- economic status and corresponding low maternal cytomegalovirus seropositivity. J Paediatr Child Health 50(5):368–372. https://doi. org/10.1111/jpc.12502 12. Bate SL, Dollard SC, Cannon MJ (2010) Cytomegalovirus sero- prevalence in the United States: the national health and nutrition examination surveys, 1988-2004. Clin Infect Dis 50(11):1439– 1447. https://doi.org/10.1086/652438 29. Robert Koch-Institut (2018) Epidemiologisches Bulletin 47/2018. doi: https://doi.org/10.25646/5806 13. Lübeck PR, Doerr HW, Rabenau HF (2010) Epidemiology of hu- man cytomegalovirus (HCMV) in an urban region of Germany: what has changed? Med Microbiol Immunol 199(1):53–60. https://doi.org/10.1007/s00430-009-0136-3 Publisher’s note Springer Nature remains neutral with regard to jurisdic- tional claims in published maps and institutional affiliations. Publisher’s note Springer Nature remains neutral with regard to jurisdic- tional claims in published maps and institutional affiliations.
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The introduction of a value‐based reimbursement programme—Alignment and resistance among healthcare providers
˜The œInternational journal of health planning and management
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R E S E A R C H A R T I C L E R E S E A R C H A R T I C L E 1 This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2022 The Authors. The International Journal of Health Planning and Management published by John Wiley & Sons Ltd. Int J Health Plann Mgmt. 2022;1–20. wileyonlinelibrary.com/journal/hpm 1 wileyonlinelibrary.com/journal/hpm DOI: 10.1002/hpm.3574 Received: 3 May 2020    Revised: 16 May 2022    Accepted: 31 August 2022 DOI: 10.1002/hpm.3574 Received: 3 May 2020    Revised: 16 May 2022    Accepted: 31 August 2022 Received: 3 May 2020    Revised: 16 May 2022    Accepted: 31 August 2022 DOI: 10.1002/hpm.3574 Thérèse Eriksson   | Lars-Åke Levin | Ann-Charlotte Nedlund Division of Society and Health (SH), Department of Health, Medicine and Caring Sciences (HMV), Linköping University, Linkoping, Sweden Abstract Abstract Reimbursement programmes are used to manage care through financial incentives. However, their effects are mixed and the programmes can motivate behaviour that goes against professional values. Value-based reimburse- ment programmes may better align professional values with financial incentives. The aim of this study is to analyse if and how healthcare providers adapt their practices to a value-based reimbursement programme that combines bundled payment with performance-based payment. Forty-one semi-structured interviews were conducted with representatives from healthcare providers within spine surgery in Sweden. Data were analysed using thematic analysis with an abductive approach and a conceptual framework based on neo-institutional theory. Healthcare providers were positive to the idea of a value-based reim- bursement programme. However, during its introduction it became evident that some aspects were easier to adapt to than others. The bundled payment provided a more compre- hensive picture of the patients' needs but to an increased administrative burden. Due to the financial impact of the bundled payment, healthcare providers tried to decrease the amount of post-discharge care. The performance-based payment was appreciated. However, the lack of finan- cial impact and transparency in how the payment was Correspondence Thérèse Eriksson, Division of Society and Health (SH), Department of Health, Medicine and Caring Sciences (HMV), Linköping University, SE-581 83, Linköping, Sweden. Email: therese.eriksson@liu.se Int J Health Plann Mgmt. 2022;1–20. 2022 The Authors. The International Journal of Health Planning and Management published by John Wiley & Sons L Highlights • The idea of value-based reimbursement was in line with professional values. • The bundled payment increased the willingness to collaborate. • The performance-based payment based on Patient reported outcome measures was too complex to understand. • Lack of support from purchaser and insufficient IT-systems caused resistance. K E Y W O R D S bundled payment, institutional change, neo-institutional theory, pay-for-performance, reimbursement, value-based reimbursement Correspondence Funding information Region Stockholm ERIKSSON et al. 2 calculated caused providers to neglect it. Healthcare provid- ers adapted their practices to, but also resisted aspects of the value-based reimbursement programme. Resistance was mainly caused by lack of understanding of how to interpret and act on new information. Providers had to face unfamiliar situations, which they did not know how to handle. Better IT-facilitation and clearer definition of related care is needed to strengthen the value-based reimbursement programme among healthcare providers. A value-based reimbursement programme seems to better align professional values with financial incentives. Value-based reimbursement programmes (VBRP) focus on activities that generate value through quality enhanc- ing, but also cost constraining, incentives. 17 Surgical procedures have been considered suitable for value-based reim- bursement because of the discrete beginning and end of a care episode. Further, the variation in recommendations in clinical guidelines 18 of spine surgery makes it suitable for a value-based reimbursement since the reimbursement level is conditioned on the outcome of the surgery. Hence, the provider must assess whether the patient will improve enough to outweigh the cost of performing the surgery. The purchaser put the financial responsibility on the provider instead of paying for the service no matter the quality. The regional public health authority, Region Stockholm, is responsible of providing healthcare to 2.4 million people. 19 Region Stockholm introduced a value-based reimbursement programme (STHLM-VBRP) within elective spine surgery in 2013. The design of the programme is based upon the thoughts of value-based healthcare (VBHC), first outlined by Porter and Teisberg in 2006, 20 and combines bundled payment with performance-based payment (also known as pay-for-performance, P4P) in a unique design. The bundled payment extends the clinical episode to 1 year after surgery, a longer period compared to other programmes 21,22; and the measure used for the performance-based payment is how much pain the patient experiences 1 year after surgery. The bundled payment extends providers' financial responsibility to incentivise coordination of care and to avoid overuse. The performance-based payment conditions the reimbursement to the outcome of the surgery and aims to enhance and sustain quality by rewarding high-performing providers. In this paper, we sought to contribute to the empirical value of neo-institutional theory, by interviewing representatives from healthcare providers on how regulative changes affect daily operations within elective spine surgery in Stockholm, Sweden. The aim of this study is to analyse if and how healthcare providers adapt their practices to a value-based reim- bursement programme that combines bundled payment with performance-based payment. In particular, we investi- gate the following research questions: How do healthcare staff experience and respond to the financial incentives the STHLM-VBRP entail? How can these experiences be understood from the perspective of neo-institutional theory in terms of alignment and resistance to the contractual changes the STHLM-VBRP imposed? 10991751, 0, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/hpm.3574 by Linkoping Universitet, Wiley Online Library on [17/10/2022]. See the Term ERIKSSON et al. 3 1 | INTRODUCTION According to economic theory, financial incentives are powerful means to shape the behaviour of actors in any market, including the health care market. The reach and limits of financial incentives in health care has been widely debated for decades. Some argue that it increases efficient use of scarce resources, 1 while others voice that it leads to unintended and unethical outcomes. 2 Studies have shown that financial incentives can be an effective way to affect physician behaviour. 3–5 However, the incentives do not always have the intended effects. 6–9 The use of finan- cial incentives has for example, been criticised for increasing production disregarding the quality of care 10 and may dampen the autonomy among physicians 11,12 who feel obliged to perform certain activities in order to get reimbursed. A study investigating physicians' perceptions of financial aspects shows that physicians commonly view financial accountability as something that comes at the expense of autonomy, and that high levels of autonomy among physi- cians is a pre-requisite for achieving high quality of care. 11 On the other hand, decreased professional autonomy may increase the control of the purchaser and therefore something positive for them. Reimbursement programmes are commonly used to generate financial incentives with the ambition of aligning the objectives of healthcare providers and the purchaser. 13,14 Thus, the incentive design in the programme must take into account the multiple agency connections (e.g., the provider as agent to both patient and purchaser) inherent in the reimbursement for health services. 15 Poorly designed reimbursement programmes may lead to undesired behav- iour and inefficient activities that decrease the legitimacy of financial incentives as an instrument to manage care. Therefore, it is also important to take the context into account, in which the reimbursement programme is introduced since the reimbursement programme alone may not be enough to affect daily operations. 16 frameworks of the shared perception, which enable sense making when meeting the ‘external world of stimuli’. 28 The cultural-cognitive pillar emphasises features of shared understanding, professional ideologies, cognitive frames or sets of collective meanings. These aspects condition how actors interpret and respond to the world around them. A focus on the cultural-cognitive pillar sheds light on how knowledge is constructed and codified in models, assump- tions and schemas, to what extent it informs and constrain behaviour. Confusion among actors usually indicates lack of support from the cultural-cognitive pillar because they do not know how to process or interpret information. Institutions are more robust when the regulative, normative and cultural-cognitive pillars are aligned and rein- force each other. Changes in one of the pillars may cause misalignment and resistance, thus weakening the institution if the pillars motivate different behaviours. However, institutions tend to converge over time and institutional theory considers misalignment of pillars as a catalyst for change. 28 The framework by Scott provides a structure to our analysis by focussing on the respective pillar, but also their interrelationship. The introduction of the STHLM-VBRP imposed contractual changes regarding the provision of elec- tive spine surgery in Region Stockholm and can thus be regarded as regulative. This change may work as a catalyst for institutional change if the introduction causes a misalignment between the pillars. If healthcare providers resist to institutional elements imposed by the VBRP, these elements will not be institutionalised. If healthcare providers align to the institutional elements imposed by the VBRP, the elements will be institutionalised. By analysing all three pillars, we intend to provide a deeper understanding on how and why certain aspects of the new reimbursement programme are institutionalised or not. 2 | UNDERSTANDING REGULATIVE CHANGES FROM THE PERSPECTIVE OF INSTITUTIONAL THEORY The implementation of VBRP varies between, but also within, different healthcare systems. 23 In the US, focus has been on moving away from fee-for-service, 24 whereas publicly financed healthcare systems in Europe mostly have focused on coordinating care among providers. 25 Thus, the introduction of the value-based reimbursement programme (VBRP) does not happen in a vacuum. This may seem obvious, but many evaluations overlook contextual factors when assessing an intervention. 5,26,27 Organisations cannot be fully understood in isolation from the exter- nal influences that arise from a wider contextual perspective. 28 Consequently, institutional theory provides suitable frameworks for examining the nature of external demands and the behaviour of organisations. We use an approach to new-institutional theory based on Scott's conceptual framework. 28 According to Scott, institutions consist of regulative, normative and cultural-cognitive pillars that in relation to each other has stabilising and meaning-making properties. The regulative pillar refers to the practice of rule-setting, monitoring, sanctioning and incentivising. It comprises formal legislation but also less formal rule making. Instrumentalism is very central within the regulative pillar, that is, individuals conform to laws and rules because they seek rewards or wish to avoid sanctions. Hence, focus on the regulative pillar sheds light on the more formalised control systems. The normative pillar encompasses values and norms. Values refer to conceptions of the preferred or the desirable, whereas norms refer to the scripts for how to reach the desirable goals and what means are legitimate in attaining them. 28 A focus on the normative pillar emphasises the stabilising influence of social beliefs and norms, both internalised and imposed by others and highlights the ‘moral roots’ of behaviour and institutions. The cultural-cognitive pillar refers to the processes and ERIKSSON et al. designing a reimbursement programme leads to an increased risk of ‘cherry picking’, that is, providers avoid clinically complicated patients to the benefit of healthier patients. However, patients with a high potential risk of needing intensive care are not covered by the commissioning contract and must be surgically treated at a hospital with access to an intensive care unit. The bundled payment should cover the individual patient's healthcare utilisation related to the spine surgery (e.g., potential complications, reoperation, rehabilitation), for the full care episode of 1 year. That means that the bundled payment includes the patient's rehabilitation, primary care, speciality care and hospital care provided by external healthcare providers (i.e., not the provider that performed the surgery). The provider that performs the surgery receives an invoice from the purchaser if an external healthcare provider treats their patient after the surgery. Hence, the bundled payment is a multi-organisational bundle of service. The bundled payment should stimulate an effective and integrated care chain by using a fixed payment to the provider for all services provided during the entire care episode. The performance-based payment is based on the outcome measure Global Assessment (GA). The measure is a retrospective transition question asked 1 year after surgery (‘How is your back/leg pain today compared to before the surgery?’). 31 The patient can choose between six response options (pain free, much better, somewhat better, unchanged, worse, did not have pain before the surgery). The registration of GA is administered and managed by the national quality registry for spine surgery in Sweden, Swespine. 32,33 The expected performance-based payment that The performance-based payment is based on the outcome measure Global Assessment (GA). The measure is a retrospective transition question asked 1 year after surgery (‘How is your back/leg pain today compared to before the surgery?’). 31 The patient can choose between six response options (pain free, much better, somewhat better, unchanged, worse, did not have pain before the surgery). The registration of GA is administered and managed by the national quality registry for spine surgery in Sweden, Swespine. 32,33 The expected performance-based payment that is included in the prospective payment is based on historical outcomes of GA, adjusted for patient characteristics. If the level of pain of the patient turns out better than expected 1 year after surgery, the healthcare provider receives an additional payment. If the level of pain turns out worse than expected the healthcare provider has to repay money to Region Stockholm. Hence, the size of the adjustment depends on the discrepancy between the actual and the expected outcome. A provider cannot receive a positive performance adjustment by performing surgery on a patient that is expected to be pain free 1 year after surgery, simply because that patient cannot get any better. On the other hand, a patient that according to historical outcomes is expected to experience a somewhat better pain will generate a positive adjustment if the actual outcome is pain free. The idea is that the performance-based payment should give financial incentives to investigate further, what can be done to improve the pain 1 year after surgery. Thus, performance-based payment is a complement to the bundle payment, to avoid healthcare providers stinting on necessary care since it may negatively affect the pain patients experience. However, healthcare providers cannot perceive the full size of the performance-based payment since it is included in the prospective payment; they only perceive the adjustment if the actual outcome deviates from the expected. 3 | THE CASE OF THE VALUE-BASED REIMBURSEMENT PROGRAMME The Swedish healthcare system is publicly financed with universal coverage. In Sweden there are 21 regions that are responsible for the provision and financing of healthcare, mainly through tax revenues. Since the regions are responsible for both provision and financing, they can be considered as both commissioning and purchasing organ- isations. As a commissioner, the region decides under what conditions healthcare organisations may provide care in the region. As a purchaser, the region pays for the healthcare consumed by the inhabitants within the region. In our article, Region Stockholm will synonymously be referred to as the purchaser. To receive public funding, private healthcare providers need accreditation by establishing a commissioning contract with the region in which they wish to deliver care. This is done either through the Public Procurement Act 29 or through the Freedom of Choice Act 30 (known as Patient Choice within healthcare), two different market-oriented solutions. Under the Public Procurement Act, healthcare providers are permitted a certain volume each year to a nego- tiated price, specific to each healthcare provider. Whereas Patient Choice is a contract that usually have no restriction on volume but with a set price, making providers compete based on quality and ultimately the patients' choice, a requirement for VBHC. 17 Patient Choice entails a continuous commissioning contract between the purchaser and healthcare providers, instead of a recurring procurement process. In 2013, Region Stockholm transitioned to accredit healthcare providers through Patient Choice instead of the Public Procurement within elective spine surgery. An elective surgery is scheduled in advance and does not involve an emergency. It was also decided that Patient Choice for elective spine surgery should entail a value-based reim- bursement programme. This reimbursement programme will be referred to as the Stockholm value-based reimburse- ment programme (STHLM-VBRP). Private healthcare providers in Region Stockholm performed most of the elective surgeries, both before and after the introduction of Patient Choice with the STHLM-VBRP. The STHLM-VBRP combines bundled payment with performance-based payment, adjusted for patient charac- teristics. When the surgical procedure is registered, the healthcare provider receives a prospective payment, which includes the bundled payment and the expected performance-based payment. The prospective payment is adjusted for age, gender, comorbidity level and surgery that covers more than two levels of the spine. The idea is to limit differences in financial risk between patients to promote need-based healthcare. Failing to adjust for case-mix when ERIKSSON et al. 5 to talk freely about the topics. To recruit respondents for interviews, we used a purposive sampling approach 35 in dialogue with the respective managers at the four clinics. We wanted the respondents to reflect the heterogeneity among staff, thus both clinically active and administrative staff were included from different professions, to attain a more comprehensive perspective. By interviewing both staff and clinicians we could reflect the potential different contextual factors and consequences of the reimbursement programme. All staff were employed by the healthcare provider and their salary was not affected by the new reimbursement programme. Before commencing the fieldwork, we obtained ethical approval (2015/94-31) from the regional board of ethics in Linköping, as well as a signed consent to participate from each respondent. The respondents were also informed that each interview was estimated to last between 30 and 60 min. We conducted semi-structured face-to-face interviews with representatives from all four accredited healthcare providers at respective spine surgery clinics. The interviews were carried out in two waves, May 2015–May 2016 and June–September 2017. The interviews were carried out in two waves to cover any potential time factor affecting how respondents experienced the reimbursement programme. For the second wave, our first option was to interview the same respondents, but because of misaligned schedules and certain staff turnover this was not always possible. In total, 41 respondents were interviewed, see Table 1. Seven respondents were interviewed in both the first and the second wave, thus 34 unique respondents were interviewed. Three interviews were conducted with two respondents at the same time after a query from the respondents. Two interviews were conducted over the telephone, both in the second wave, with respondents who had already been interviewed face-to-face during the first wave. To make the respondent feel comfortable in the situation, each interview started with more general questions about the respond- ent's profession and responsibilities. 35 Each interview lasted between 20 and 60 min. There was some variation in length of the interviews because respondents had been involved and affected by the reimbursement programme to a varying degree. However, each interview started by checking available time in order to adjust the disposition to the topic. The interviews were carried out in Swedish. All but one interview were audio recorded and transcribed verbatim in Swedish. The interviews were analysed using a thematic analysis. 4 | STUDY DESIGN AND METHODS We conducted a systematic comparison of case studies, using respondents' own reports since neo-institutional anal- ysis assumes that institutions are, in effect, manifested through individuals' attitudes, beliefs and motivation. The case studies of interest were healthcare providers accredited within elective spine surgery and reimbursed based on the STHLM-VBRP. At the time of the introduction of the STHLM-VBRP, there were three accredited healthcare providers in Region Stockholm. A fourth provider was accredited in 2017. All of the providers were private and for-profit, one clinic was a professional partnership whereas the other three clinics were part of a larger healthcare organisation (however, some had a history of being a cooperative/professional partnership). Two providers were located in Stockholm city, one in a Stockholm suburb and the fourth in a neighbouring region (Region Sörmland). Despite being located in different regions, all healthcare providers were providing care under the same contractual conditions after the introduction of the STHLM-VBRP. An interview guide was designed based on the structure of the reimbursement programme. The interview guide was designed as an aide-memoire, 34 to ensure that all aspects were covered but still allowing for the respondent ERIKSSON et al. by Scott, 28 to connect the empirical findings to the conceptual framework based on institutional pillars. An iterative process followed, where identified themes were classified, grouped and regrouped. Only the quotes used in the arti- cle was translated from Swedish to English. The originators of the quotes used in ‘Findings’ have been encrypted to ensure that individual respondents cannot be identified. The healthcare providers will be denoted A–D followed by a number indicating the respondent. Further, in the following text, post-discharge care will be denoted as external care when provided by a provider other than the initial spine surgery clinic. 5 | FINDINGS The main themes correspond to the aspects of the STHLM-VBRP that the healthcare providers experienced as most important: the bundled payment, the performance-based payment, and the continuous contract. Each theme is followed by subthemes that were generated with the inductive approach. 36 We adopted an abductive approach that allows for interaction with previous and newly discovered knowledge, thus allows for a combination of an inductive and deduc- tive approach. 37 Accordingly, the interview guide provided a helpful structure for beginning the analysis, but the themes were adapted when new aspects were discovered. The first step in the analysis was to identify what aspects of the new regulative framework healthcare providers experienced, how these aspects were perceived and whether they had any effect on their daily operations. Emerging themes were later sorted into the neo-institutional framework TA B L E 1   Represented professions and functions among the respondents First wave Second wave Total Profession  Spine surgeon 4 6 10  Registered nurse 7 9 16  Physiotherapist 1 4 5  Accountant/controller 3 5 8  Other professions 2 0 2 Total 17 24 41 Function  Head of clinic, CEO 2 4 6  Administrative staff 9 7 16  Working in different health professions 6 13 19 Total 17 24 41 TA B L E 1   Represented professions and functions among the respondents TA B L E 1   Represented professions and functions among the respondents Represented professions and functions among the respondents ERIKSSON et al. 7 7 5.1.2 | Post-discharge care—An administrative nightmare Another aspect of the increased financial responsibility was that invoices often seemed to include care that was not related to the spine surgery. This resulted in additional administrative work for administrators at healthcare providers, but also for physicians since it required medical knowledge to audit the health records of the patients. Respondents said that it would be impossible to keep auditing health records manually in the long term and emphasised the need of better IT-facilitation for a sustainable system. And should something happen after surgery that is related to the surgery – then of course, you have to take responsibility. The only thing that I find tiresome… is that they shift a lot of costs onto the healthcare provider that aren't related to the surgery. It's just that parenthesis, otherwise I definitely think you should be responsible for what you do, absolutely. D6 The unrelated care was experienced as an ‘unfair part of the contract’ (B7), a way for the purchaser to pass on costs to the provider. Another problem with unrelated care was that they had to spend time and resources on writing an appeal to argue as to why they should not pay the bill, thus increasing the administration even further. C1 The financial responsibility for post-discharge care affected healthcare providers. In particular, the cost of treat- ing infections was extremely high and affected them greatly. Some respondents also said that the clinics in Stockholm all had very low infection rates. Thus, it was rather a matter of bad luck than something that was preventable and hence impossible to reduce further. Therefore, it seemed unfair to have them pay for necessary care for patients. It is more that it feels unfair, when it comes down to a complication that you reasonably couldn't have avoided in any way, that you later receive a bill of half a million, it doesn't feel fair. It is more this sense of justice, you have done your absolute best and sometimes you get hit, this penalty approach is not good. D3 Thus, respondents expressed a level of discontent with the inclusion of infections in the responsibility of post-discharge care. Infections requires intensive care, something the private spine surgery clinics cannot provide themselves. 5.1.1 | A more holistic perspective All healthcare providers were strongly affected financially by the increased cost responsibility. Hence, all healthcare providers experienced a strong incentive to take care of complications related to the surgery to avoid paying other healthcare providers. It further stimulated the providers to discuss how to decrease the amount of external care at other hospitals/providers. What I think is the difference, when I look at other areas of patient choice, we have a more complete picture of the patient. Otherwise you only see the surgical procedure. So I think that is the major differ- ence, that you have a lot more patient responsibility for much longer. It also creates other routines; it creates another way of working. C2 Yes, it actually drives private healthcare providers to take responsibility. Not just under the knife, but that you actually own the process for a while longer. B8 The invoices for external care created a new flow of information to the providers when their patients were treated elsewhere. Healthcare providers expressed that this procedure gave them a more comprehensive perspective of the care chain. They realised that not all patients contacted them if they experienced complications after the surgery. That there is a slightly clearer follow-up on how the patients turned out in the end. Because clearly patients may be a bit different, some may not always call you if they don't feel well. They think like ‘nah but I guess this is normal’, now we can see it in a different way – more clearly. That there is a slightly clearer follow-up on how the patients turned out in the end. Because clearly patients may be a bit different, some may not always call you if they don't feel well. They think like ‘nah but I guess this is normal’, now we can see it in a different way – more clearly. D4 D4 I think it's good that you have to take that responsibility because it also means that you are more active in taking care of your own complications. You have to because of financial reasons. If one of our patients ends up at a university hospital or something like that, then we get a huge invoice and its's not – it has happened – it's not funny. Like you see half a week's production just disappears. Yes, it's pretty tough but I still think it's good. 5.1.1 | A more holistic perspective ERIKSSON et 8 8 ERIKSSON et al. Two of the healthcare providers perceived the more prominent role of physiotherapy as a natural step in improv- ing spine surgery care. Healthcare professionals argued that it was good to assess patients from different perspec- tives, that physiotherapists can better assess the physiotherapy the patient has had previously. We have a holistic perspective all the time because we have the reception, we have the surgery, we have the physiotherapists and in the city we provide – we are accredited within Patient Choice reha- bilitation. So I think we have a holistic approach regarding the spine. A3 At the other two clinics it was experienced as a big transition from being a spine surgery clinic responsible for the patient from the surgery until discharge, to suddenly being responsible for post-discharge care and rehabilitation. From 1 day to the next, physiotherapists suddenly had a great responsibility. One of the providers began to drastically change their patient flow by involving physiotherapists in the assessment but also by opening a centrally located outpatient clinic. Another provider had a more reserved attitude to the new responsibility making no major changes. We have started up a completely new flow prior to surgery that we are implementing at the moment and slowly getting used to. B5 Yes, a little understanding would feel good because, as I said, referring patients to avoid things they actually need. […] I feel really sad about it and I think it's pretty difficult to work that way. It would be nice to have an understanding of why I say it … I do as I'm told but that doesn't feel that good all times. D8 D8 Another problem was that it was not possible to assess what patients had been treated for by external physiother- apists after surgery. This caused frustration and the spine surgery clinics felt a lack of control. Respondents expressed the need for better registration of what kind of treatment patients received when consulting a physiotherapist. We've experienced that patients who have had minor surgery, that may not really be in need of much physiotherapy, go to a physiotherapist in town and then loads of invoices drop into our mailbox and we can't figure out how that happened. We don't really have any control of the situation. But the patients do have the right to consult a physiotherapist, and then the physiotherapist can bill us. 5.1.3 | A more prominent role for physiotherapy Due to the bundled payment the cost of physiotherapy became salient to the spine surgery clinics and acquired a far more central position as compared to before the introduction of the VBRP model. The close relationship between spine surgery and physiotherapy became more evident and it was discussed at a management level. Now management can try to concentrate on how… before we've ignored physiotherapy. Now, we must include physiotherapy – what physiotherapy do we really need? And how should we work with it and to put those thoughts into practice. A1 9 C1 C1 The spine surgery clinic wants to be able to assess whether the treatment is related to the spine surgery or not, and the necessity of the treatment. Three out of the four clinics, offered the patients regular return visits to the clinic for physiotherapy, in an attempt to avoid being billed by external physiotherapists. This was also logistically problematic when patients lived far from the clinic and/or already had an established relationship with another physiotherapist. To increase the likelihood of the patient returning to the clinic for physiotherapy after surgery, one healthcare provider started with physiotherapy before the surgery to establish a relationship with an internal physiotherapist. The damned patients who don't come here. The damned patients who don't come here. D7 As an effect, physiotherapy could be perceived as something that should not be recommended by healthcare professionals. They could not send patients in need of physiotherapy to other physiotherapists because of the finan- cial responsibility. But what we see is that the costs for physiotherapy are quite high because the patient still has a choice. We have no choice; we have signed this contract. The patient has a choice not to come here, where we already have the staff for that kind of activity. B8 But … we can't control patients, we can only ask them not to go, and if they should go, we want them to go to this physiotherapist with whom we have an agreement. But if they don't go there, we can't force them either. Because they have a free choice. D2 Many experienced it as frustrating not having any tools to handle the free will of the patient and wished for better support from Region Stockholm. Because of Patient Choice they could not limit the care the patient sought elsewhere. Some respondents suggested the possibility of a patient contract as a solution. A contract that guaranteed the patient a certain amount of physiotherapy related to the surgery, but the patient would be charged for any additional care that exceeds the agreed amount. However, that kind of action needs regulative support from Region Stockholm. Does increased accessibility and freedom of choice require a patient contract? With an increased cost-responsibility for post-discharge care, respondents recognised that it was more important now to establish a good relationship with the patient. If the patient wanted to return to their practice, they would not have to pay other healthcare providers. To increase the chance of the patient returning for post-surgery care, all 10 ERIKSSON et al. healthcare providers had increased their accessibility by extending opening hours, two providers also opened up a more centrally located outpatient clinic. We have better control and the patient has better access to us I think. So for the patient I think it's an advantage actually. And the most positive effect is probably that we feel that we must hold on to our patients, we lose out by not caring about them, I must say. A6 It was however logistically problematic for the providers to make patients come back in the case of complica- tions, or to do physiotherapy when the easiest option for the patient was to turn to their primary care centre, emer- gency department or a physiotherapist with whom they already had an established relationship. This was described as unfair, to place this coordinating and integrating responsibility on them alone. They further expressed difficulties in scheduling staff; there is no point of having a physiotherapist at the clinic if the patients never use it. In a way I think it's good. On the other hand, I think it's bad because you can't control if a patient chooses a provider other than yourself. Which makes it important to speak the same language with the external providers. You cannot force people to come back after discharge, they may think it's better to go to their own physiotherapist. And we can sometimes differ in the way we see things, how much care the patient needs. C3 The bundled payment made it important to build a network of external physiotherapists (and other healthcare providers), with whom the spine surgery clinics could cooperate and agree upon an adequate level of care. Another problem respondents described was how to obtain information on whether their patient sought care elsewhere, and how to offer them the possibility to come back. Once they receive the invoice, it is too late to react, thus not giving them the chance to affect the healthcare provided. Respondents said that it felt like a punch in the stomach to receive an invoice from another hospital that had treated, a patient they could have treated themselves had they been offered the opportunity. And it can be frustrating if it is abused out there, that someone gets loads of mediocre unnecessary care, I don't think that's okay. So we can try to have a good dialogue with them, to write referrals and write some guidelines and such. C3 Patients usually seek care at an emergency department and are hospitalised. And then all possible things can be done without anyone contacting us. They can perform surgery and they can do – we don't even know that the patient is there. And then the patient is hospitalised for two weeks or some- thing, being treated, and different things are done, and then suddenly out of no-where we receive a bill … it can cost a month's budget, for care we don't have any opportunity to influence. D1 Respondents said that some kind of automatic notification when their patient was registered elsewhere would be helpful, to give them a fair chance to offer their services. However, they also acknowledged the importance of respecting the choice of the patient and their option to say no and stay with the external healthcare provider. 5.1.5 | Communication with external healthcare providers became important, but it was difficult to make them cooperate. Providers within STHLM-VBRP acknowledged that there was no direct incentive for external healthcare providers to put time and resources into contacting them. However, from a wider perspective it would be more efficient since the spine surgery clinic has the clinical history of the patient. They meant it would be more efficient if they got the chance to take care of their own patients instead of using the resources of hospitals or other facilities dedicated to more seri- ous or complex conditions. Respondents said that they had realised that they must work actively for more integrated care, to contact external healthcare providers to set up a dialogue, and together design optimal post-surgery care. ERIKSSON et al. 11 5.2.1 | The lack of financial impact Healthcare providers experienced the performance-based payment as something positive. The idea of being reim- bursed based on results instead of activity, was encouraging. It was aligned with the professional values of ensuring the patient is free from pain 1 year after surgery. Respondents also expressed that they did not feel constrained by the reimbursement model or the performance measure used. We have our own goals, but they coincide with the goal that we want to maximise for the patient – that they should be as well as possible. So I don't think we have different goals, rather that the finan- cial goals are in line with the goal you have with the patient, so to speak. C2 C2 Quality improvement was considered important and something they continuously worked with before the introduction of STHLM-VBRP. All providers appreciated the idea of a performance-based payment being used as a ERIKSSON et al. 12 complement to the bundled payment. But it had no financial impact. The share of the performance-based adjustment was too small in comparison to the prospective payment and the invoices for external care. Respondents meant that a larger proportion of the payment had to be tied to performance to generate an effect. The performance-based payment isn't anything we look at every month, in that way, unless it diverges a lot. It goes alright, and as long as our patients feel good we don't really follow-up on it that intensely. D4 D4 There is a certain idea behind it, so you have to make sure that the bonus, that the quality bonus works. Because otherwise, if you only take a part of it and don't care about the other part – then some can make as much money as they want while others can't. It's completely wrong! Why then would you do all this, without doing this part right? There must be an incentive there. A10 Some meant that the level or structure of the performance-based payment had to be adjusted, otherwise the whole model would lose its purpose and might have negative effects on quality. Furthermore, the healthcare provid- ers were not able to control the performance-based payment they received from Region Stockholm. 5.2.2 | The lack of transparency in how the payment was calculated Respondents were positive to the idea of the performance-based payment but did not understand how they could make use of it. The lack of transparency for how the performance-based payment was calculated made the model more difficult to understand. Respondents said that they had been promised a demo that showed how different variables affected the performance-based payment. They had not yet received any demo but said that it would most probably be helpful to understand what aspects that affect the reimbursement level. I agree with the idea – yes. But, then there's a lot that we don't really know so much about when it comes down to what matters when this performance-based payment is calculated. A2 Because we want to understand, why did we get minus 15,000 and why did we get 10 for that? But then, it's so big that you cannot handle it. So you would want something just like this [snaps fingers], some kind of search engine. D2 The complication responsibility of post-discharge care feels much more concrete, that there we can do something and we know what we're doing. Whereas this performance-based payment, there we feel like we're just groping in the dark. A6 Compared to the bundled payment, respondents experienced the performance-based payment as vaguer and more complex. Respondents said that the performance-based payment was so low that it had no financial impact, it was not worth to monitor and assess outcomes measured with GA as a part of their daily operations. surgery, some respondents expressed a concern regarding potential shifts in case-mix. The lack of effect of the performance-based payment raised concerns regarding cherry picking. In the worst-case scenario surgeons would only perform surgery on patients they knew for sure would benefit from it, thus not ‘taking a chance’ with patients suffering from comorbidities. At the same time, they argued that they should not perform surgery on patients who would not benefit from it, thus recognising the complexity of the problem. Obviously, when you do more risky things, you know that you take a greater medical and financial risk. Because if the surgery fails we must face the consequences. And of course, in the worst case scenario Patient Choice could lead to some patients being excluded. Then personally, I don't think I actually do that, but theoretically it could absolutely be possible. Especially if you have a lot of patients, but if you only have a few patients obviously you can't turn them away. If you have a lot of patients, then cherry-picking may be a problem. C1 However, when the fourth provider entered the market the competition increased, and no provider could afford to say no to patients. Providers focused on how to build processes that decreased the need of post-discharge care and physiotherapy. Respondents said that due to the extended cost-responsibility, the reimbursement level was rela- tively lower compared to before and this gave incentive to increase production. Thus, the decreased reimbursement level in combination with an increased competition, prevented cherry picking according to respondents. | Concerns regarding potential shifts in case-mix cerns regarding potential shifts in case-mix Within elective spine surgery, it was experienced by the respondents that it can be difficult to tell if a patient will benefit from surgery or not. When relating the reimbursement to how much pain the patient experiences after a ERIKSSON et al. 13 A1 Even though all healthcare providers agreed that the reimbursement level was at reasonable level for spine surgery procedures, it was relatively low in relation to the cost for post-discharge care. We might be more effective because we have had to make some cuts. We have had to assess our working routines, and that's not only negative. The coin always has two sides, so it can actually be positive as well. But it has been difficult. B9 One healthcare provider expressed concern regarding the new level, fearing that it would eventually affect patients negatively. Although they admitted that this new level had forced them to make changes that were for the better, but they feared that it would not be enough. Especially without future adjustment of the reimbursement to inflation. 5.3 | The continuous contract 5.3.1 | A decreased level of uncertainty allows for long-term planning but with a diminishing reimbursement level The continuous commissioning contract allowed accredited healthcare providers to make long-term plans because they did not have to fear losing the contract during a competitive procurement process. Because of Patient Choice, we got more freedom to be able to decide ourselves what we think will be the best for the patient. That made us realise immediately that we must do something preoperatively and postoperatively. A7 Providers expressed frustration with the inability of the purchaser to monitor and assess the quality of the healthcare provided. Respondents meant that this inability caused a competition based on price, regardless of quality under procurement. I've been involved in quite a few procurements and in the end it's only the price that matters. And there are many actors who are not serious, who don't take on the most difficult or weighty procedures, more difficult patients and put in really low bids during the procurement process. A serious clinic can't practice under those circumstances. A1 All providers had a positive attitude to competition based on quality instead of price. However, they raised concerns regarding the lack of adjustment to the price level in line with inflation. Region Stockholm did not adjust the reimbursement level during the first 4 years and respondents doubted that this was going to happen at any time in the near future. It's the price erosion that I'm worried about. When there is no adjustment to inflation, and the margins get to the level that we must begin to reduce the quality. So that is the most important question right now. ERIKSSON 14 14 ERIKSSON et al. (−) Confusion caused by the lack of transparency in how the payment was calculated. The continuous contract  A continuous contract between provider and purchaser. (+) The decreased uncertainty allows healthcare providers to make plans for the long term. (+) Increased autonomy. Providers can design their own processes. A set price without adjusting the price level in line with inflation. (+ −) Quality enhancing but the lack of adjustment makes providers uncertain about the purchaser's intentions. (−) Healthcare providers still perceive Region Stockholm to put price before quality. No restrictions on volume. (+) The providers can assess patients without any restrictions, everyone in need should be treated. (+) More information on which patients benefit from surgery is needed. The importance of support and communication with the purchaser. (+) More information, give control to providers to be able to follow-up on care. (−) No constitutive schema to handle information. TA B L E 2   The findings in relation to the neo-institutional pillars, (+) indicates that the aspect aligns with the STHM-VBRP, whereas (−) indicates resistance to the STHLM-VBRP TA B L E 2   The findings in relation to the neo-institutional pillars, (+) indicates that the aspect aligns with the STHM-VBRP, whereas (−) indicates resistance to the STHLM-VBRP 6 | THE ALIGNMENT AND MISALIGNMENT BETWEEN REGULATIVE, NORMATIVE, AND CULTURAL-COGNITIVE ELEMENTS In Table 2, we summarise the alignment and misalignment between the regulative, normative, and cultural-cognitive elements among healthcare providers. The bundled payment implied a new way of thinking about elective spine surgery. The idea of taking a greater responsibility for the care chain and increase cooperation among providers was supported by all three pillars. However, how to act on these ideas was not obvious to healthcare providers. As mentioned in section two, confusion usually indicates a lack of support from the cultural-cognitive pillar. Especially how to better integrate physiotherapy and increase cooperation with external healthcare providers. To know how to act they ‘must learn about the new contract and gain an understanding of it’ (B7). Without a shared understanding they cannot find appropriate means of how to adapt their practice. Despite efforts to cooperate with external healthcare providers, it was impossible to reach all of them and establish consent regarding optimal medical practice. Respondents experienced the situation as rather hopeless without any authority to impose sanctions if care, in their opinion, deviated from optimal medical practice. Since respondents experienced cooperation with other healthcare providers as difficult, they discussed a patient contract as a potential solution by holding patients accountable for excessive rehabilitation. Hence, this hopelessness resulted in new normative and cultural-cognitive values that lacked regulative support. New normative and cultural-cognitive values should be taken into consideration by the purchaser when updating the reimbursement programme. The definition of related care is important since it affects the range of healthcare providers' responsibility. Because of the vague definition, the responsibility could be perceived as both narrow and wide. Healthcare providers that adopted a narrower definition, experienced invoices pertaining to unrelated care as something unfair. It affected their relations with the purchaser because they felt used and experienced it as an unfair strategy. On the other hand, healthcare providers that adopted the wider definition of related care had a more neutral perspective on the invoices from Region Stockholm. However, the experienced ambiguity resulted in healthcare providers not knowing how to design their processes, since they did not know to what extent they were responsible. The vague definition in the contract weakened the regulative pillar. Due to the fact that providers did not know how to assess related care nor 15 ERIKSSON et al. (−) The logic ‘the customer is always right’ is not aligned with the professional logic and agency. (−) No constitutive schema. Regulative Normative Cultura The bundled payment  Increased financial responsibility for post discharge care. (+) New identity, not only a spine surgery clinic. Must handle care- flows outside their clinic. (+) A ne cre of a  Invoices for external care. (+) High financial impact, incentive to coordinate post-discharge care and discuss physiotherapy at a managerial level. (−) D oth con righ (−) Reviewing and disputing invoices is time consuming for both administrative and clinical staff. Information about post-discharge care. (+) Increased focus on the relation between provider and patient resulted in better accessibility. (−) The righ pro  No authority to impose sanctions on other healthcare providers. (−) Spine surgery clinics have no authority to sanction undesired behaviour. (−) No  Vague definition of related care in the responsibility for post- discharge care. (−) Allows for different interpretation of related care. Unfair strategy by Region Stockholm, decreases trust between provider and purchaser. (−) Con on unc wh to h (+) Something Region Stockholm cannot sort out. As a provider of care, they are one of the best suited to solve the problem. (−) Con def (−) No scr The performance-based payment  Reimbursement based on patient reported outcome measure 1 year after surgery. (+) Aligned with professional values, no constraining effect on perceived autonomy. (+) Perc the ma  Healthcare providers only perceived the performance-based adjustment, not the full payment. (−) The adjustment had no financial impact. Instead, providers focussed on how to decrease post-discharge care that had a more direct impact. (−) No per we goo  Healthcare providers did not receive information of how the payment was calculated for each patient. (−) The performance-based payment was perceived as too complex. It was not worth the effort to understand it better. (−) Con tran wa The continuous contract  A continuous contract between provider and purchaser. (+) The decreased uncertainty allows healthcare providers to make plans for the long term. (+) Incr des  A set price without adjusting the price level in line with inflation. (+ −) Quality enhancing but the lack of adjustment makes providers uncertain about the purchaser's intentions. (−) Hea Reg bef  No restrictions on volume. (+) The providers can assess patients without any restrictions, everyone in need should be treated. (+) Mo pat nee  The importance of support and communication with the purchaser. (+) More information, give control to providers to be able to follow-up on care. (−) No info TA B L E 2   The findings in relation to the neo-institutional pillars, (+) indicates that STHM-VBRP, whereas (−) indicates resistance to the STHLM-VBRP Regulative Normative Cultural-cognitive The bundled payment  Increased financial responsibility for post discharge care. (+) New identity, not only a spine surgery clinic. Must handle care- flows outside their clinic. (+) A new way of thinking, requires creative solutions. No shared logic of action. Invoices for external care. (+) High financial impact, incentive to coordinate post-discharge care and discuss physiotherapy at a managerial level. (−) Difficulties cooperating with other providers. It is beyond their conceptual world; do not have the right tools. (−) Reviewing and disputing invoices is time consuming for both administrative and clinical staff. Information about post-discharge care. (+) Increased focus on the relation between provider and patient resulted in better accessibility. (−) The logic ‘the customer is always right’ is not aligned with the professional logic and agency. No authority to impose sanctions on other healthcare providers. (−) Spine surgery clinics have no authority to sanction undesired behaviour. (−) No constitutive schema. Vague definition of related care in the responsibility for post- discharge care. (−) Allows for different interpretation of related care. Unfair strategy by Region Stockholm, decreases trust between provider and purchaser. (−) Confusion. Long lead times on disputed invoices increase uncertainty and obstruct providers when developing new processes to handle post-surgery care. (+) Something Region Stockholm cannot sort out. As a provider of care, they are one of the best suited to solve the problem. (−) Confusion because of vague definition of responsibility. (−) No constitutive schema or mental scripts. The performance-based payment  Reimbursement based on patient reported outcome measure 1 year after surgery. (+) Aligned with professional values, no constraining effect on perceived autonomy. (+) Perceived as an innovative step by the purchaser, proof that quality matters. Healthcare providers only perceived the performance-based adjustment, not the full payment. (−) The adjustment had no financial impact. Instead, providers focussed on how to decrease post-discharge care that had a more direct impact. (−) No difference with or without the performance-based payment, they were already working towards good outcomes. Healthcare providers did not receive information of how the payment was calculated for each patient. (−) The performance-based payment was perceived as too complex. It was not worth the effort to understand it better. Cultural-cognitive (+) A new way of thinking, requires creative solutions. No shared logic of action. (−) Difficulties cooperating with other providers. It is beyond their conceptual world; do not have the right tools. (−) Difficulties cooperating with other providers. It is beyond their conceptual world; do not have the right tools. (−) Confusion. Long lead times on disputed invoices increase uncertainty and obstruct providers when developing new processes to handle post-surgery care. (+) Something Region Stockholm cannot sort out. As a provider of care, they are one of the best suited to solve the problem. (−) Confusion because of vague definition of responsibility. (−) No constitutive schema or mental scripts. (−) No constitutive schema or mental scripts. (+) Aligned with professional values, no constraining effect on perceived autonomy. (+) Perceived as an innovative step by the purchaser, proof that quality matters. (+) Perceived as an innovative step by the purchaser, proof that quality matters. Reimbursement based on patient reported outcome measure 1 year after surgery. (+) Aligned with professional values, no constraining effect on perceived autonomy. (+) Perceived as an innovative step by the purchaser, proof that quality matters. Healthcare providers only perceived the performance-based adjustment, not the full payment. (−) The adjustment had no financial impact. Instead, providers focussed on how to decrease post-discharge care that had a more direct impact. (−) No difference with or without the performance-based payment, they were already working towards good outcomes. Healthcare providers did not receive information of how the payment was calculated for each patient. (−) The performance-based payment was perceived as too complex. It was not worth the effort to understand it better. (−) Confusion caused by the lack of transparency in how the payment was calculated. The continuous contract  A continuous contract between provider and purchaser. (+) The decreased uncertainty allows healthcare providers to make plans for the long term. (+) Increased autonomy. Providers can design their own processes. A set price without adjusting the price level in line with inflation. (+ −) Quality enhancing but the lack of adjustment makes providers uncertain about the purchaser's intentions. (−) Healthcare providers still perceive Region Stockholm to put price before quality. No restrictions on volume. (+) The providers can assess patients without any restrictions, everyone in need should be treated. (+) More information on which patients benefit from surgery is needed. The importance of support and communication with the purchaser. Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/hpm.3574 by Linkoping Universitet, Wiley Online Library on [17/10/2022]. See the Terms and Condit how to act on it, there was no support from the cultural-cognitive nor the normative pillar to strengthen the regula- tive pillar. Hence, the vague definition weakened the institution by motivating different behaviours. Providers appreciated the performance-based payment and perceived it as a quality statement by the purchaser. To reduce the pain further than expected, it is crucial for healthcare providers to come to an understanding of what else that can be done in addition to surgery. For a spine surgery clinic, this can be challenging since their specialisa- tion in fact is spine surgery. Hence, the payment incentivise interprofessional collaboration and holistic healthcare since surgery alone may not be enough to reduce the pain any further. However, healthcare providers received no information about the expected performance-based payment nor the patient's expected pain reduction. The lack of transparency in how the performance-based payment was calculated made the payment too complex to understand, and because of the lack of financial impact, it was not worth trying to understand. The intended incentives to improve quality failed to have impact on behaviour since it lacked support from the cultural-cognitive pillar (they did not understand it) and the normative pillar (it was not worth understanding). Because of the strong financial impact of the bundled payment, healthcare providers focussed on how to minimise costs rather than maximising their outcome regarding the performance measure. The continuous contract with no restriction regarding volume was supported by all three pillars; it decreased uncertainty to healthcare providers and increased their autonomy. Respondents did however express the need of more research to better distinguish the patients that ultimately benefit from surgery and what kind of physiotherapy that is motivated. The idea of a set price to promote competition based on quality was aligned with the normative and cultural-cognitive pillars of healthcare providers. However, respondents experienced that the lack of adjustment of the price level in line with inflation was undercutting quality and the existence of their practice. As one respond- ent (B7) put it ‘they squeeze every penny out of us making it really hard for us to survive as a business’. This caused normative resistance because respondents experienced it as unfair, and it seemed like Region Stockholm still put price before quality. Our analysis showed that the value-based reimbursement programme caused misalignment between the insti- tutional pillars among healthcare providers. Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/hpm.3574 by Linkoping Universitet, Wiley Online Library on [17/10/2022]. See the Terms and Condit Even though providers supported the general idea of the value-based reimbursement programme, how to act on these ideas and adapt their practice to it required comprehensive under- standing of the programme. Cultural-cognitive (+) More information, give control to providers to be able to follow-up on care. (−) No constitutive schema to handle information. (−) No difference with or without the performance-based payment, they were already working towards good outcomes. (−) No difference with or without the performance-based payment, they were already working towards good outcomes. (−) The adjustment had no financial impact. Instead, providers focussed on how to decrease post-discharge care that had a more direct impact. (−) Confusion caused by the lack of transparency in how the payment was calculated. (−) The performance-based payment was perceived as too complex. It was not worth the effort to understand it better. (−) Confusion caused by the lack of transparency in how the payment was calculated. A continuous contract between provider and purchaser. (+) The decreased uncertainty allows healthcare providers to make plans for the long term. (+) Increased autonomy. Providers can design their own processes. A set price without adjusting the price level in line with inflation. (+ −) Quality enhancing but the lack of adjustment makes providers uncertain about the purchaser's intentions. (−) Healthcare providers still perceive Region Stockholm to put price before quality. No restrictions on volume. (+) The providers can assess patients without any restrictions, everyone in need should be treated. (+) More information on which patients benefit from surgery is needed. The importance of support and communication with the purchaser. (+) More information, give control to providers to be able to follow-up on care. (−) No constitutive schema to handle information. (+) The decreased uncertainty allows healthcare providers to make plans for the long term. (−) Healthcare providers still perceive Region Stockholm to put price before quality. (+ −) Quality enhancing but the lack of adjustment makes providers uncertain about the purchaser's intentions. (+) The providers can assess patients without any restrictions, everyone in need should be treated. (−) No constitutive schema to handle information. (+) More information, give control to providers to be able to follow-up on care. ERIKSSON et al. 16 51, 0, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/hpm.3574 by Linkoping Universitet, Wiley Online Library on [17/10/2022]. See the Terms and Condi purchaser bodies (governmental or private) have been identified as a barrier for institutionalisation of elements of VBHC (such as VBRP) across different healthcare systems. 23 Thus, better dialogue between purchaser and providers in combination with compatible and agile IT-systems may enhance cooperation. The purchaser has to facilitate coop- eration between healthcare providers to make the cost of cooperation as low as possible. The struggle of healthcare providers does on the other hand show that patients have a free choice to choose whomever they prefer. purchaser bodies (governmental or private) have been identified as a barrier for institutionalisation of elements of VBHC (such as VBRP) across different healthcare systems. 23 Thus, better dialogue between purchaser and providers in combination with compatible and agile IT-systems may enhance cooperation. The purchaser has to facilitate coop- eration between healthcare providers to make the cost of cooperation as low as possible. The struggle of healthcare providers does on the other hand show that patients have a free choice to choose whomever they prefer. The performance-based payment has been criticised to have a negative impact on some aspects of medical profes- sionalism. 43 Participants were positive to the performance-based payment because it did not ‘force’ them to focus on irrelevant outcome measures. However, the lack of transparency and financial impact made the performance-based payment too complex to understand and follow-up. Quality improvement requires ongoing feedback at all stages, and that everyone involved is aware of the complexity of changing the culture of the organisation. 42,44 The slow feedback from Region Stockholm caused frustration among healthcare providers. It made it more difficult for them to adjust to the new structure. Participants in our study found that their focus on financial aspects had increased with the STHLM-VBRP, compared to before. A potential explanation can be the experienced unbalanced incentive structure between the bundled payment and the performance-based payment. Thus, healthcare providers focussed on minimising post-discharge care instead of quality improvement, contrary to other studies where VBHC decreased the focus on financial aspects. 41 It has been argued that financial incentives are not sufficient to affect daily operations in a setting where governance and manage- ment philosophies are firmly grounded within the New Public Management paradigm. 16 We argue that financial incen- tives are, if introduced in the right institutional context, an effective tool to manage care. 51, 0, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/hpm.3574 by Linkoping Universitet, Wiley Online Library on [17/10/2022]. See the Terms and Condi This highlights the importance of acknowledging the institutional context when designing, implementing, and evaluating reimbursement programmes. Another important aspect was the transition from periodic re-contracting to a continuous commissioning contract, which according to respondents decreased uncertainty of the future and allowed them to make long-term plans. However, it was also clear that a continuous contract requires relevant feedback from the purchaser at the right time. Once again, this highlights the importance of good communication and supporting IT-systems. Especially since the text in the commissioning contract can be interpreted in different ways (as the vague definition of related care proofed), therefore the relation to the purchaser organisation is more than just a commissioning contract. Even though this study was performed in a context of Swedish healthcare, it investigates management prac- tices that are globally diffused and therefore should be of relevance for other healthcare contexts as well. Despite differences in healthcare organisation and funding between healthcare systems across the world there seem to be universal enablers and barriers for implementation of VBRP. Based on a comparison of four different healthcare systems, Mjåset et al. 23 found that three aspects were universal for a successful implementation: (1) strong support from governmental/purchaser bodies, (2) IT-systems that allow seamless system integration and up-to-date outcome measurement across the full cycle of care, and (3) involvement of the medical community to make sure that the intrin- sic values of working in healthcare are aligned with management strategies. These aspects are further manifested by our findings from studying the introduction of the STHLM-VBRP. Because of contextual differences between and within healthcare systems, it is important to use a theoreti- cal framework to structure findings and enable comparison. 27 We included all four healthcare providers that were reimbursed based on the STHLM-VBRP. Despite the limited number of providers, they performed a majority of the elective spine surgeries in Sweden. However, by that limited number, we cannot claim to cover all experiences. To cover other perspectives from the same reimbursement programme, future studies could focus on how the purchaser organisation act and adapt their practice to a value-based reimbursement programme. It would also be of great inter- est to study the reimbursement programme in a context that involves more providers. The introduction of STHLM-VBRP had three defining features: the bundled payment, the performance-based payment and the continuous contract between provider and purchaser. 7 | DISCUSSION The bundled payment imposed strong financial incentives thus making it crucial for all healthcare providers to assess the whole care chain of their patients. Due to the responsibility, healthcare providers became more prone to strive for optimal healthcare consumption. Similar findings have been reported in other studies, where bundled payment reduced healthcare use and costs. 21,38 The different perceptions, of the legitimacy of increasing healthcare providers responsibility for post-discharge, is in line with studies showing that spine surgeons allocate major responsibility to healthcare systems to manage the cost of healthcare. 39 With STHLM-VBRP, Region Stockholm moves towards inte- grated care with patient-centeredness and a greater responsibility to healthcare providers, thus in line with VBHC. 40 Participants in our study experienced a need for better cooperation between healthcare providers. Similar find- ings were reported in a study that investigated the effects of introducing VBHC in another Swedish region. 41 They found that the introduction of VBHC raised awareness about cooperation being necessary to create value for patients. The introduction of VBHC increased cooperation within the hospital but it was difficult to establish cooperation with external healthcare providers. 41 In the case of STHLM-VBRP, the private healthcare providers experienced difficulties in making other providers cooperate when there was no corresponding incentive for external providers. Thus, insuf- ficient organisational structure of healthcare hinders structural changes. 42 The difficulty in establishing cooperation reflected that health care providers did not have cognitive schemas of how to coordinate post-discharge care nor how to act on the information they received from the invoices of external care and rehabilitation. Insufficient support from ERIKSSON et al. 17 CONFLICT OF INTEREST The authors declare that they have no conflict of interest. 51, 0, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/hpm.3574 by Linkoping Universitet, Wiley Online Library on [17/10/2022]. See the Terms and Condi The general perception among providers about these features was positive. However, our analysis showed that the resistance to STHLM-VBRP was mainly caused by confusion in how to interpret and act on the information they received, that is, misalignment with cultural-cognitive pillar. The misalignment between the institutional pillars in healthcare providing organisations can ERIKSSON et al. 18 DATA AVAILABILITY STATEMENT The data generated and analysed during the current study are not publicly available due to the inclusion of potentially sensitive individual data. The ethical approval includes a statement that the data will be kept in a private repository but are available from the corresponding author on reasonable request. be seen as a catalyst for change because of instable institutions. Whether this change will lead to more robust insti- tutions depends on whether healthcare providers can come to an understanding of how to coordinate post-discharge care, have access to sufficient IT-systems, and whether the purchaser is able to support the healthcare providers when taking these steps towards integrated healthcare. ORCID Thérèse Eriksson https://orcid.org/0000-0001-6855-6169 ACKNOWLEDGEMENTS We would like to express our gratitude to the healthcare providing organisations and the respondents for participat- ing. We would also like to express our gratitude to Region Stockholm for financial support. ETHICS STATEMENT Before commencing the fieldwork, the study obtained ethical approval (2015/94-31) from the regional board of ethics in Linköping, as well as a signed consent to participate from each respondent. REFERENCES 1. Conrad DA, Perry L. Quality-based financial incentives in health care: can we improve quality by paying for it? Annu Rev Publ Health. 2009;30(1):357-371. https://doi.org/10.1146/annurev.publhealth.031308.100243 2. Sandel MJ. What Money Can't Buy: The Moral Limits of Markets. 1st paperback ed. Farrar, Straus & Giroux; 2013. 3. Roland M, Campbell S. Successes and failures of pay for performance in the United Kingdom. N Engl J Med. 2014;370(20):1944-1949. https://doi.org/10.1056/nejmhpr1316051 3. Roland M, Campbell S. Successes and failures of pay for performance in the United Kingdom. N Engl J Med. 2014;370(20):1944-1949. https://doi.org/10.1056/nejmhpr1316051 4. Martinsson P, Persson E. Physician behavior and conditional altruism: the effects of payment system and uncertain health benefit. Theory Decis. 2019;87(3):365-387. https://doi.org/10.1007/s11238-019-09714-7 4. Martinsson P, Persson E. Physician behavior and conditional altruism: the effects of payment system and uncertain health benefit. Theory Decis. 2019;87(3):365-387. https://doi.org/10.1007/s11238-019-09714-7 5. Scott A, Liu M, Yong J. Financial incentives to encourage value-based health care. Med Care Res Rev: MCR 32. https://doi.org/10.1177/1077558716676594 6. Osipovič D, Allen P, Shepherd E, et al. Interrogating institutional change: actor's attitudes to competition and cooperation in commissioning health services in England. Public Adm. 2016;94(3):823-838. https://doi.org/10.1111/padm.12268 7. Hansson SO. Medical ethics and New Public Management in Sweden. Camb Q Healthc Ethics. 2014;23(3):261-267. https://doi.org/10.1017/s0963180113000868 8. Eijkenaar F, Emmert M, Scheppach M, Schoffski O. Effects of pay for performance in health care: a systematic review of systematic reviews. Health Policy. 2013;110(2–3):115-130. https://doi.org/10.1016/j.healthpol.2013.01.008 9. Harrison MI. Implementing Change in Health Systems: Market Reforms in the United Kingdom, Sweden and The Netherlands: Market Reforms in the United Kingdom, Sweden and The Netherlands. SAGE Publications; 2004. 9. Harrison MI. Implementing Change in Health Systems: Market Reforms in the United Kingdom, Sweden and The Netherlands: Market Reforms in the United Kingdom, Sweden and The Netherlands. SAGE Publications; 2004. 10. Hills JM, Weisenthal B, Sivaganesan A, Bydon M, Archer KR, Devin CJ. Value based spine care: pay volume. Semin Spine Surg. 2019;31(1):12-19. https://doi.org/10.1053/j.semss.2018.07.004 10. Hills JM, Weisenthal B, Sivaganesan A, Bydon M, Archer KR, Devin CJ. Value based spine care: paying for outcomes, not volume. Semin Spine Surg. 2019;31(1):12-19. https://doi.org/10.1053/j.semss.2018.07.004 11. Forsberg E, Axelsson R, Arnetz B. Effects of performance-based reimbursement on the professional autonomy and power of physicians and the quality of care. Int J Health Plan Manag. 2001;16(4):297-310. https://doi.org/10.1002/ hpm.640 11. Forsberg E, Axelsson R, Arnetz B. Effects of performance-based reimbursement on the professional autonomy and power of physicians and the quality of care. The Public Procurement Act (LOU) 2016:1145. Riksdagen; 2016. 30. SFS 2008:962. The Act on Systems of Choice (LOV). Vol 2008:962. Riksdagen; 2008. 30. SFS 2008:962. The Act on Systems of Choice (LOV). Vol 2008:962. Riksdagen; 2008. 31. Parai C, Hagg O, Lind B, Brisby H. The value of patient global assessment in lumbar spine surgery: an on more than 90,000 patients. Eur Spine J. 2017;27(3):554-563. https://doi.org/10.1007/s00586-017 32. Stromqvist B, Fritzell P, Hagg O, Jonsson B, Sanden B. Swespine: the Swedish spine register: the 2012 report. Eur Spine J. 2013;22(4):953-974. https://doi.org/10.1007/s00586-013-2758-9 33. Swedish Society of Spinal Surgeons. Swespine 25 years 2018 annual report. 2018. 19. http://swespine.se/Aarsrap- porter.htm2018 34. Burgess RG. In the Field: An Introduction to Field Research. Routledge; 1991. 34. Burgess RG. In the Field: An Introduction to Field Research. Routledge; 1991. 35. Ruhl K. Qualitative Research Practice. A Guide for Social Science Students and Researchers. JSTOR; 2004. 36. Braun V, Clarke V. Using thematic analysis in psychology. Qual Res Psychol. 2006;3(2):77-101. https://doi. org/10.1191/1478088706qp063oa 37. Alvesson M. Interpreting Interviews. SAGE; 2011. Accessed February 29, 2020. https://methods.sagepub.com/book/ interpreting-interviews 38. Finkelstein A, Ji Y, Mahoney N, Skinner J. Mandatory medicare bundled payment program for lower extremity joint replacement and discharge to institutional postacute care: interim analysis of the first year of a 5-year randomized trial. JAMA. 2018;320(9):892-900. https://doi.org/10.1001/jama.2018.12346 39. Pendi A, Farhan SA-DB, Raphael D, Rinehart JB, Kain ZN, Bederman SS. View of U.S. spine surgeons regarding cost reduction measures. J Spine Surg. 2018;4(2):311-318. https://doi.org/10.21037/jss.2018.05.15 39. Pendi A, Farhan SA-DB, Raphael D, Rinehart JB, Kain ZN, Bederman SS. View of U.S. spine surgeons regarding cost reduction measures. J Spine Surg. 2018;4(2):311-318. https://doi.org/10.21037/jss.2018.05.15 40. Porter ME. What is value in health care? N Engl J Med. 2010;363(26):2477-2481. https://doi.org/10.1056/ nejmp1011024 40. Porter ME. What is value in health care? N Engl J Med. 2010;363(26):2477-2481. https://doi.org/10.1056/ nejmp1011024 41. Nilsson K, Baathe F, Andersson AE, Wikstrom E, Sandoff M. Experiences from implementing value-based healthcare at a Swedish University Hospital – an longitudinal interview study. BMC Health Serv Res. 2017;17(1):169. https://doi. org/10.1186/s12913-017-2104-8 41. Nilsson K, Baathe F, Andersson AE, Wikstrom E, Sandoff M. Experiences from implementing value-based healthcare at a Swedish University Hospital – an longitudinal interview study. BMC Health Serv Res. 2017;17(1):169. https://doi. org/10.1186/s12913-017-2104-8 42. Sheard L, Marsh C, O'Hara J, Armitage G, Wright J, Lawton R. 14. Dranove D, White WD. Agency and the organization of health care delivery. Inquiry. 1987;24(4):405-415. 15. Arrow KJ. The Economics of Agency. Harvard University Press; 1984. 16. Ellegard LM, Glenngard AH. Limited consequences of a transition from activity-based financing to budget- ing: four reasons why according to Swedish hospital managers. Inquiry. 2019;56:46958019838367. https://doi. org/10.1177/0046958019838367 16. Ellegard LM, Glenngard AH. Limited consequences of a transition from activity-based financing to budget- ing: four reasons why according to Swedish hospital managers. Inquiry. 2019;56:46958019838367. https://doi. org/10.1177/0046958019838367 17. Porter ME. Value-based health care delivery. Ann Surg. 2008;248(4):503-509. https://doi.org/10.1097/sla.0b013e- 31818a43af 17. Porter ME. Value-based health care delivery. Ann Surg. 2008;248(4):503-509. https://doi.org/10.1097/sla.0b013e- 31818a43af 18. Foster NE, Anema JR, Cherkin D, et al. Prevention and treatment of low back pain: evidence, challenges, and promising directions. Lancet (London, Engl). 2018;391(10137):2368-2383. https://doi.org/10.1016/s0140-6736(18)30489-6 19. Statistics Sweden. Population in the country, counties and municipalities on 31 December 2019 and population change in 2019. 2020. Accessed February 13, 2021. https://www.scb.se/en/finding-statistics/statistics-by-subject-area/popu- lation/population-composition/population-statistics/pong/tables-and-graphs/yearly-statistics--municipalities-coun- ties-and-the-whole-country/population-in-the-country-counties-and-municipalities-on-31-december-2019-and-pop- ulation-change-in-2019/ 20. Porter ME, Teisberg EO. Redefining Health Care: Creating Value-Based Competition on Results. Harvard Business School Press; 2006. 21. Ryan AM. Medicare bundled payment programs for joint replacement: anatomy of a successful payment reform. JAMA. 2018;320(9):877-879. https://doi.org/10.1001/jama.2018.11787 22. Ugiliweneza B, Kong M, Nosova K, et al. Spinal surgery: variations in health care costs and implications for episode-based bundled payments. Spine. 2014;39(15):1235-1242. https://doi.org/10.1097/brs.0000000000000378 22. Ugiliweneza B, Kong M, Nosova K, et al. Spinal surgery: variations in health care costs and implications for episode-based b dl d ( ) h //d / /b 23. Mjåset C, Ikram U, Nagra NS, Feeley TW. Value-based health care in four different health care systems. NEJM Catal Innov Care Deliv. 2020;1(6). 24. Porter ME, Lee TH. The strategy that will fix health care. Harv Bus Rev. 2013. www.hbr.org2013 25. EIT Health. Implementing Value-Based Health Care in Europe: Handbook of Pioneers. EIT Health; 2020. 26. Damberg CL, Sorbero ME, Lovejoy SL, Martsolf GR, Raaen L, Mandel D. Measuring success in health care value-based purchasing programs: findings from an environmental scan, literature review, and expert panel discussions. Rand Health Q. 2014;4(3):9. 27. Walshe K. Understanding what works—and why—in quality improvement: the need for theory-driven evaluation. Int J Qual Health Care. 2007;19(2):57-59. https://doi.org/10.1093/intqhc/mzm004 28. Scott WR. Institutions and Organizations: Ideas, Interests and Identities. 4th ed. SAGE Publications, Inc.; 2014. 28. Scott WR. Institutions and Organizations: Ideas, Interests and Identities. 4th ed. SAGE 29. SFS 2016:1145. 10991751, 0, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/hpm.3574 by Linkoping Universitet, Wiley Online Library on [17/10/2022]. See the Term ERIKSSON et al. 19 . Dranove D, White WD. Agency and the organization of health care delivery. Inquiry. 1987;24(4):405-415 . Arrow KJ. The Economics of Agency. Harvard University Press; 1984. REFERENCES Int J Health Plan Manag. 2001;16(4):297-310. https://doi.org/10.1002/ hpm.640 12. Numerato D, Salvatore D, Fattore G. The impact of management on medical professionalism: a review. Sociol Health Illn. 2012;34(4):626-644. https://doi.org/10.1111/j.1467-9566.2011.01393.x 12. Numerato D, Salvatore D, Fattore G. The impact of management on medical professionalism: a review. Sociol Health Illn. 2012;34(4):626-644. https://doi.org/10.1111/j.1467-9566.2011.01393.x 13. Conrad DA. The theory of value-based payment incentives and their application to health care. Health Serv Res. 2015;50(suppl 2):2057-2089. https://doi.org/10.1111/1475-6773.12408 13. Conrad DA. The theory of value-based payment incentives and their application to health care. Health Serv Res. 2015;50(suppl 2):2057-2089. https://doi.org/10.1111/1475-6773.12408 The patient feedback response framework – understand- ing why UK hospital staff find it difficult to make improvements based on patient feedback: a qualitative study. Soc Sci Med (1982). 2017;178:19-27. https://doi.org/10.1016/j.socscimed.2017.02.005 20 20 ERIKSSON et al. 43. Lester H, Matharu T, Mohammed MA, Lester D, Foskett-Tharby R. Implementation of pay for performance in primary care: a qualitative study 8 years after introduction. Br J Gen Pract. 2013;63(611):e408-415. https://doi.org/10.3399/ bjgp13x668203 How to cite this article: Eriksson T, Levin L-Å, Nedlund A-C. The introduction of a value-based reimbursement programme—alignment and resistance among healthcare providers. Int J Health P 2022;1-20. https://doi.org/10.1002/hpm.3574 How to cite this article: Eriksson T, Levin L-Å, Nedlund A-C. The introduction of a value-based reimbursement programme—alignment and resistance among healthcare providers. Int J Health Plann Mgmt. 2022;1-20. https://doi.org/10.1002/hpm.3574
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Proving the Correctness of Knowledge Graph Update: A Scenario From Surveillance of Adverse Childhood Experiences
Frontiers in big data
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Proving the Correctness of Knowledge Graph Update: A Scenario From Surveillance of Adverse Childhood Experiences 1 Nuffield Department of Public Health, Big Data Institute, University of Oxford, Oxford, United Kingdom, 2 Department of Pediatrics, The University of Tennessee Health Science Center-Oak Ridge National Laboratory, Center for Biomedical Informatics, College of Medicine, Memphis, TN, United States Knowledge graphs are a modern way to store information. However, the knowledge they contain is not static. Instances of various classes may be added or deleted and the semantic relationship between elements might evolve as well. When such changes take place, a knowledge graph might become inconsistent and the knowledge it conveys meaningless. In order to ensure the consistency and coherency of dynamic knowledge graphs, we propose a method to model the transformations that a knowledge graph goes through and to prove that the new transformations do not yield inconsistencies. To do so, we express the knowledge graphs as logically decorated graphs, then we describe the transformations as algorithmic graph transformations and we use a Hoare-like verification process to prove correctness. To demonstrate the proposed method in action, we use examples from Adverse Childhood Experiences (ACEs), which is a public health crisis. Edited by: Mayank Kejriwal, University of Southern California, United States United States Reviewed by: Yanghua Xiao, Fudan University, China Ivan Lee, University of South Australia, Australia *Correspondence: Jon Haël Brenas jon.brenas@bdi.ox.ac.uk Arash Shaban-Nejad ashabann@uthsc.edu Reviewed by: Yanghua Xiao, Fudan University, China Ivan Lee, S Reviewed by: Yanghua Xiao, Fudan University, China Ivan Lee, University of South Australia, Australia *Correspondence: Jon Haël Brenas jon.brenas@bdi.ox.ac.uk Arash Shaban-Nejad ashabann@uthsc.edu Keywords: program verification, graph transformation, cloning, merging, knowledge graph, adverse childhood experiences Received: 28 January 2021 Accepted: 06 April 2021 Published: 03 May 2021 Received: 28 January 2021 Accepted: 06 April 2021 Published: 03 May 2021 In this paper, we propose a method to tackle this issue. The proposed method aims to identify what are the transformations entailed by adding or removing a piece of information or an axiom to make sure that the knowledge graph remains consistent with the ontology. In our previous works, we used graph transformation to represent and analyze changes in knowledge-based global health surveillance systems (Brenas et al., 2017, 2018; Al-Manir et al., 2018). We represent the ontology in C2 (Gradel et al., 1997) for convenience. The initial modification of the knowledge graphs will be assumed to be through a query language but we will represent the transformations as graph transformations and use Hoare-like verification methods (Hoare, 1969) to produce the proofs. The ORIGINAL RESEARCH published: 03 May 2021 doi: 10.3389/fdata.2021.660101 1. INTRODUCTION Knowledge graphs have become ubiquitous as a framework to represent entities and the relations that connect them. Thanks to the layer of semantic information, it has become possible to add meaning to the entities and relations contained in graphs and to reason about the knowledge they contain. Because graphs contain knowledge, they are expected to change with new information added or removed depending on outside events. In a similar way, the changes in the semantic layers may cause the meaning associated with each entity to change. Through such modifications, a knowledge graph can become inconsistent with the ontology that describes it (Zhang, 2002), rendering the knowledge, and thus the graph, meaningless. Specialty section: This article was submitted to Data Mining and Management, a section of the journal Frontiers in Big Data Received: 28 January 2021 Accepted: 06 April 2021 Published: 03 May 2021 Received: 28 January 2021 Accepted: 06 April 2021 Published: 03 May 2021 Citation: Brenas JH and Shaban-Nejad A (2021) Proving the Correctness of Knowledge Graph Update: A Scenario From Surveillance of Adverse Childhood Experiences. Front. Big Data 4:660101. doi: 10.3389/fdata.2021.660101 May 2021 | Volume 4 | Article 660101 Frontiers in Big Data | www.frontiersin.org Correctness of Knowledge Graph Update Brenas and Shaban-Nejad The set C (resp. R) naturally depends on the logic. It is constructed such that C contains all “unary” (resp. “binary”) predicates of the logic and the closure under their constructors, i.e., class (resp. property) assertions. modifications depend only on the structure of each axiom and the action that is performed and not on the actual ontology or graph. It is thus possible to prove that they behave correctly in an abstract way that is independent of the actual knowledge graph that is modified. In particular, this means that the complexity of the verification task is independent of the size of the actual knowledge graph and only depends on the size of the specification that is proven to be correct. To make our reasoning easier to understand, we describe axioms from the ontology both as first-order formulae and in a notation closer to Description Logics. In this paper, we focus on the lower spectrum of the expressivity for the axioms but the verification framework that underpins our method works with the full expressiveness of C2 (Gradel et al., 1997), the two-variable fragment of first-order logic with counting, that can express most axioms in OWL.1 Informally, C2 contains all formulas of first order logic that can be written using only two variables, as well as the counting quantifier ∃>n and its negation ∃≤n. As an example, ∃>2x.φ(x) can be translated in first order logic as ∃x0, x1.φ(x0) ∧ φ(x1) ∧x0 ̸= x1, i.e., there exist at least two different x such that φ(x). To showcase how the proposed method works, we use examples coming from Adverse Childhood Experiences (ACEs), which is a major public health concern. ACEs are negative events, e.g., abuse, witnessing violence, etc, that have been linked to various negative health outcomes and risky behaviors (Felitti et al., 1998). The ACEs Ontology and knowledge graph have been described in Brenas et al. (2019a,c). Here, we will use a clinical example. Patients or their parents are interviewed and screened for ACEs. Citation: If they suffer from some ACEs, e.g., if they are homeless or live in a place with mold, they are assigned to a social worker. If they suffered from a different set of ACEs, e.g., emotional abuse, they are assigned to a psychologist. Additionally, if they agree to be part of a study, they need to have provided a phone number or an email address and they will be paired with a caseworker. In order to avoid overworking the staff, social workers can only be assigned 10 patients and psychologists five. If the number of patients is higher than the available number of professionals, they are redirected toward a different clinic and it is agreed that a new hire is required. To explain how knowledge graphs are updated and modified, we use graph transformations. The most usual way to deal with graph transformations is by using an algebraic approach rooted in category theory (Barendregt et al., 1987). In this paper, we will use a more algorithmic approach that, we argue, is more suited to verification. In order to build transformations, we first define atomic actions that will be composed to form more elaborate actions. Definition 2.2. Let C (resp. R) be a set of node (resp. edge) labels. An elementary action, say a, may be of the following forms: In Section 2, we will introduce the formal framework that underpins our method. In Section 3, we show the applicability of this framework through some examples. Finally, in Section 4, we discuss the limitations of the method and further work. • a node addition addN(i) (resp. node deletion delN(i)) where i is a new node (resp. an existing node). It creates the node i. i has no incoming nor outgoing edge and it is not labeled (resp. it deletes i and all its incoming or outgoing edges). • a node addition addN(i) (resp. node deletion delN(i)) where i is a new node (resp. an existing node). It creates the node i. i has no incoming nor outgoing edge and it is not labeled (resp. it deletes i and all its incoming or outgoing edges). • a node label addition addC(i, c) (resp. node label deletion delC(i, c)) where i is a node and c is a label in C. It adds the label c to (resp. removes the label c from) the labeling of node i. 1Web Ontology Language (OWL) (accessed on January 2021). 2. LOGIC, GRAPH REWRITING, AND VERIFICATION • an edge addition addE(e, i, j, r) (resp. edge deletion delE(e, i, j, r)) where e is an edge, i and j are nodes and r is an edge label in R. It adds the edge e with label r between nodes i and j (resp. removes all edges with source i and target j with label r), i.e., s(e) = i, t(e) = j and 8E(e) = r (resp. ∀e′ ∈E.s(e′) ̸= i or t(e′) ̸= j or 8E(e′) ̸= r). Each knowledge graph is composed of a graph and an ontology that assigns meaning to its nodes and edges. In the following, we present a fairly informal and succinct introduction to our framework. We hope to manage to give readers an idea of the logical foundation of our method without spending too much time and space on information that would not be relevant to most end-users. Readers interested in a more formal and in-depth description can find it in Brenas et al. (2016a, 2018b). An action α is a finite sequence of atomic actions. An action α is a finite sequence of atomic actions. It selects a node, b, and creates a new node named a (addN(a)) and connects a to b with an edge labeled with lives_with (addE(a, b, lives_with)). This process is achieved by two functions: the weakest- precondition wp(s, Q) and the verification condition vc(s, Q) for a strategy s and a post-condition Q. More details can be found in Brenas et al. (2016a). The definitions of these functions are given in Figures 2, 3, respectively. A rule is applied when a match for the left-hand side is found in the knowledge graph that we want to modify. We also define strategies that describe the order in which the rules of a logically decorated graph rewriting system are to be applied. The weakest preconditions and verification conditions introduce new logic constructors to deal with elementary actions called substitutions and written Q[a] where Q is a logic formula and a is an action. Intuitively, a graph G is a model of the formula Q[a] if and only if G[a], the graph obtained by performing action a on G, is a model of φ. Definition 2.4. Given a logically decorated graph rewrite system GRS, a strategy is a word of the following language defined by s, where ρ is any rule in GRS: y s : = ǫ (Empty Strategy) ρ (Rule) s ⊕s (Choice) s; s (Composition) s∗ (Closure) s : = ǫ (Empty Strategy) ρ (Rule) s ⊕s (Choice) s; s (Composition) s∗ (Closure) Definition 2.7 (Substitutions). To each elementary action a is associated a substitution, written [a], such that for all graphs G and formula φ, (G is a model of φ[a]) ⇔(G[a] is a model of φ). Given two logically decorated graphs G and G′ and a strategy s, we denote by G ⇒s G′ that it is possible to obtain G′ by applying s to G. It is worth noting that the weakest precondition of a closure, s∗, is invs, an invariant for that closure. This invariant is not part of the original specification but needs to be specified. We thus modify the notion of specification. Intuitively, ǫ means “do nothing,” ρ is an application of the rule, s ⊕s is the application of either of the two strategies (but not both), s; s is the application composition and s∗applies the strategy as many times as possible. Definition 2.8 (Annotated Specification). An action α is a finite sequence of atomic actions. An annotated specification SP is a triple {Pre}(R, s){Post} where Pre and Post are formulas (of a given logic), R is a graph rewriting system, s is a strategy and every closure in s is annotated with an invariant. Example 2.2. For instance, strategy ρ0; (ρ∗ 0 ⊕ρ1) means “apply ρ0 followed by either as many applications of ρ0 as possible or one application of ρ1.” Example 2.4. As the strategy in Example 2.3 contains a closure, we annotate it. {φ0}({ρ0}, ρ∗ 0{φ0}){φ0} is a possible annotated specification. Example 2.4. As the strategy in Example 2.3 contains a closure, we annotate it. {φ0}({ρ0}, ρ∗ 0{φ0}){φ0} is a possible annotated specification. Previously, we have shown how to use logics to label edges and nodes of graphs. We now go a little further and show how we can use logics to define specifications for the transformations we want to perform, i.e., how to define conditions that we want to be satisfied by the graph after the transformation is performed, given that it may have satisfied another (possibly identical) set of conditions initially. Now that the notions of the weakest precondition and the verification condition are defined, we can look back at the original problem we were trying to solve. We define a formula that represents the correctness of a specification. Definition 2.9 (Correctness formula). We call correctness formula of an annotated specification SP = {Pre}(R, s){Post}, the formula: Definition 2.5 (Specification). A specification SP is a triple {Pre}(R, s){Post} where Pre (the precondition) and Post (the post- condition) are formulas (of a given logic), R is a graph rewriting system and s is a strategy. correct(SP) = (Pre ⇒wp(s, Post)) ∧vc(s, Post). Example 2.3. Let us assume that we want a specification describing part of Example . φ0 ≡ ∀x.Psychologist(x) ⇒ ∃≤5y.(Patient(y) ∧assigned_to(y, x)) is a formula that states that at most five patients are assigned to each psychologist. Then, SP0 ≡ {φ0}({ρ0}, ρ∗ 0){φ0} states that if φ0 is true, it will still be true after applying ρ0 as many times as possible. Example 2.3. Let us assume that we want a specification describing part of Example . φ0 ≡ ∀x.Psychologist(x) ⇒ ∃≤5y.(Patient(y) ∧assigned_to(y, x)) is a formula that states that at most five patients are assigned to each psychologist. An action α is a finite sequence of atomic actions. An action α is a finite sequence of atomic actions. Actions are not enough to describe all the transformations we want to perform, as they require the knowledge of the exact nodes and edges that are going to be modified. In order to enable the selection of nodes that satisfy a condition, we use rewriting rules and logically decorated graph rewriting systems. In order to represent the knowledge graphs, we use logically decorated graphs where both nodes and edges are labeled with formulae that are part of the ontology language. Definition 2.1. Let C (resp. R) be a set of node labels (resp. edge labels), a logically decorated graph is a tuple (N, E, 8N, 8E, s, t) where N is a set of nodes, E is a set of edges, 8N : N →P(C) is a node labeling function, 8E : E →P(R) is an edge labeling function, s : E →N is a source function and t : E →N is a target function. The source function s and the target function t define the orientation of an edge. For instance, edge e connects node s(e) to node t(e). Definition 2.3. A rule ρ is a pair (LHS,α) where LHS, called the left-hand side, is a logically-decorated graph and α, called the right- hand side, is an action. Rules are usually written LHS →α. A logically decorated graph rewriting system is a set of rules. May 2021 | Volume 4 | Article 660101 Frontiers in Big Data | www.frontiersin.org 2 Correctness of Knowledge Graph Update Brenas and Shaban-Nejad In order to prove the correctness of a specification, we use a Hoare-like approach (Hoare, 1969). The idea is that it is possible to split the transformation into elementary changes that impact the graph in a known and controlled way. In such a situation, given the post-condition that needs to be achieved, it becomes possible to generate the weakest precondition that ensures that the post-condition will be satisfied. This can then be iterated to generate the weakest precondition for the whole transformation. Example 2.1. Figure 1 contains an example of rule. It selects a node, b, and creates a new node named a (addN(a)) and connects a to b with an edge labeled with lives_with (addE(a, b, lives_with)). Example 2.1. Figure 1 contains an example of rule. An action α is a finite sequence of atomic actions. To show some examples, we use the Adverse Childhood Experiences Ontology (ACESO) (Brenas et al., 2019a) as the source for the axioms. The systematic study of adverse childhood experiences and their health outcomes is recent and new data and knowledge are routinely added in this field. As a result, both the knowledge graphs and the associated ontology are likely to change frequently. Theorem 2.2. (Brenas et al., 2016a) C2 is closed under substitutions. Example 3.1. Let us assume that the change that we want to perform is the addition of a new node, pa, which is labeled with PhysicalAbuse. This modification would be equivalent to performing the action a0 ≡addN(pa); addC(pa, PhysicalAbuse). ACESO contains the axiom PhysicalAbuse ⊆ Abuse that can be translated in C2 as ∀x.PhysicalAbuse(x) ⇒ Abuse(x). Performing a0 would make the knowledge graph inconsistent with the ontology as, if x = pa, PhysicalAbuse(x) ∧ ¬Abuse(x) is true. Instead, the transformation that is actually performed is a1 ≡ addN(pa); addC(pa, PhysicalAbuse); addC(pa, Abuse). In that case, the correctness formula is (∀x.PhysicalAbuse(x) ⇒ Abuse(x)) ⇒(∀x.(PhysicalAbuse(x)∨x = pa) ⇒(Abuse(x)∨x = pa)) which is obviously valid. The knowledge graph is thus still consistent with the ontology. For all the logics that are closed under substitution, the proof consists in a set of rewrite rules that conserve the interpretation. For instance, given C0 an atomic concept, σ a substitution, i and j individuals and π0 a program: • ⊤σ ; ⊤ • C0[addC(C0, i)] ; C0 ∨{i} • (∃r0.C)[delE(i, j, r0)] ; (¬{i} ∧∃r0.(C[delE(i, j, r0)])) ∨ (∃r0.(¬{j} ∧C[delE(i, j, r0)])) • ⊤σ ; ⊤ • C0[addC(C0, i)] ; C0 ∨{i} • (∃r0.C)[delE(i, j, r0)] ; (¬{i} ∧∃r0.(C[delE(i, j, r0)])) ∨ (∃r0.(¬{j} ∧C[delE(i, j, r0)])) • ⊤σ ; ⊤ • C0[addC(C0, i)] ; C0 ∨{i} • (∃r0.C)[delE(i, j, r0)] ; (¬{i} ∧∃r0.(C[delE(i, j, r0)])) ∨ (∃r0.(¬{j} ∧C[delE(i, j, r0)])) • C0[addC(C0, i)] ; C0 ∨{i} Another possible problem is that the logic needs to be able to express the existence (and absence) of a match. First-order logic can express App(ρ) by using an existential variable for every node of the left-hand side of the rule ρ. This is not possible in the other types of logics we considered as they do not allow to define an unlimited number of variables. There is thus a limitation on what can appear on the left-hand side of the rules. An action α is a finite sequence of atomic actions. Then, SP0 ≡ {φ0}({ρ0}, ρ∗ 0){φ0} states that if φ0 is true, it will still be true after applying ρ0 as many times as possible. Theorem 2.1 (Soundness). Let SP = {Pre}(R, s){Post} be an annotated specification. If correct(SP) is valid, then for all graphs G, G′ such that G ⇒s G′, G is a model of Pre implies G′ is a model of Post. Deciding whether a specification is correct can be translated into deciding the validity of a given formula. This is one of the main reasons why we focused on decidable logics in this section. Another possible choice is to only consider tractable logic so that verification becomes achievable in a reasonable timeframe. Definition 2.6 (Correctness). A specification SP is said to be correct ifffor all graphs G, G′ such that G ⇒s G′ and G is a model of Pre (i.e., Pre is a logical consequence of the labeling of G), then G′ is a model of Post. Definition 2.6 (Correctness). A specification SP is said to be correct ifffor all graphs G, G′ such that G ⇒s G′ and G is a model of Pre (i.e., Pre is a logical consequence of the labeling of G), then G′ is a model of Post. May 2021 | Volume 4 | Article 660101 Frontiers in Big Data | www.frontiersin.org 3 Correctness of Knowledge Graph Update Brenas and Shaban-Nejad FIGURE 2 | Weakest preconditions w.r.t. actions and strategies, where a (resp. α, αρ) stands for an elementary action (resp. action, the right-hand side of a rule ρ) and Q is a formula. FIGURE 3 | Verification conditions for strategies. FIGURE 2 | Weakest preconditions w.r.t. actions and strategies, where a (resp. α, αρ) stands for an elementary action (resp. action, the right-hand side of a rule ρ) and Q is a formula. FIGURE 3 | Verification conditions for strategies. under consideration are correct and, thus, the update can take place. The decidability of the validity problem for the logic used to label the graph is not, however, the only condition for the decidability of the correctness problem. The definitions of the weakest preconditions introduced substitutions as a new formula constructor. In order for the correctness problem to be decidable, these new constructs must be expressible in the logic, i.e., the logic must be closed under substitutions. In the following, we will be using C2. An action α is a finite sequence of atomic actions. As it is possible to modify the knowledge graph by adding information contained in new nodes, it is also possible to add new edges. In the previous example, only the new node, pa, was really affected by the modification of the knowledge graph and thus a simple action was enough to update the knowledge graph to preserve consistency. The next example, on the other hand, requires a rule to be applied. Frontiers in Big Data | www.frontiersin.org 3. APPLICATION ¬lives_with(y, x) is true. Instead, the transformation that is actually performed is the application of rule ρ1 shown in Figure 4. In that case, the correctness formula is (∀x, y.lives_with(x, y) ⇒ lives_with(y, x)) ⇒(∀x, y.(lives_with(x, y) ∨(x = a ∧y = b) ∨(x = b ∧y = a)) ⇒(lives_with(y, x) ∨(x = b ∧y = a) ∨(x = a ∧y = b)) which is obviously valid. From the previous two examples, one can observe how the transformations and the axioms interact. As a result, it is possible to define a system of transformation rewriting rules that, given the intended action and the form of an axiom, generates a new transformation of the knowledge graph that can be proved correct independently of the actual knowledge graph and ontology. For instance, the previous examples show that when in presence of an axiom of the form C ⊆D where C and D are unary predicates (i.e., classes in OWL Lite), an elementary action addC(i, C) should be replaced with the action addN(i, C); addN(i, D) while, in presence of an axiom of the form Symmetric(R) where R is a binary predicate (i.e., a property in OWL Lite), an elementary action addN(i) should be left unchanged. Figure 5 shows these two rules plus additional ones. FIGURE 5 | Rules rewriting transformations depending on the form of the axioms in the ontology. FIGURE 5 | Rules rewriting transformations depending on the form of the axioms in the ontology. FIGURE 6 | Rules inserting the knowledge that Alice, who did not exist in the knowledge base, is a girl who lives with Bob. Example 3.3. Let us now combine the previous two examples. We assume that we want to add a new person Alice, represented by the new node a, to the knowledge graph. We additionally want to insert the knowledge that Alice is a girl and that she lives with Bob, represented by the already existing node b. The initial rule that would be applied is rule ρ2 from Figure 6. Provided that the ontology contains the axioms Girl ⊆Child and Symmetric(lives_with), all six rules in Figure 5 can be applied. The order in which they are applied does not change the final result, i.e., the rewriting system is convergent, and the final result is Rule ρ3 in Figure 6. Frontiers in Big Data | www.frontiersin.org 3. APPLICATION When adding or removing knowledge from a knowledge graph, there is a risk to harm its consistency with the ontology that describes its underlying structure. As a result, additional actions may be needed before making any change to a knowledge graph. In this section, we present some of the transformations that can be enacted to make an update. We will then prove that the specifications resulting from the axioms and the transformations Example 3.2. Let us assume that the change that we want to perform is the creation of a new node, a, and a new edge, e, linking a to the already existing node b with an edge labeled lives_with. This modification would be equivalent to applying Rule ρ0 shown in Figure 4. ACESO contains the axiom Symmetric(lives_with) that May 2021 | Volume 4 | Article 660101 Frontiers in Big Data | www.frontiersin.org 4 Correctness of Knowledge Graph Update Brenas and Shaban-Nejad FIGURE 5 | Rules rewriting transformations depending on the form of the axioms in the ontology. FIGURE 6 | Rules inserting the knowledge that Alice, who did not exist in the knowledge base, is a girl who lives with Bob. FIGURE 5 | Rules rewriting transformations depending on the form of the axioms in the ontology. FIGURE 4 | Rules creating a new node a and connecting it via property lives_with to the node b. can be translated in C2 as ∀x, y.lives_with(x, y) ⇒lives_with(y, x). Applying ρ0 would make the knowledge graph inconsistent with the ontology as, if x = a and y = b, lives_with(x, y) ∧ ¬lives_with(y, x) is true. Instead, the transformation that is actually performed is the application of rule ρ1 shown in Figure 4. In that case, the correctness formula is (∀x, y.lives_with(x, y) ⇒ lives_with(y, x)) ⇒(∀x, y.(lives_with(x, y) ∨(x = a ∧y = b) ∨(x = b ∧y = a)) ⇒(lives_with(y, x) ∨(x = b ∧y = a) ∨(x = a ∧y = b)) which is obviously valid. gy f y y ¬lives_with(y, x) is true. Instead, the transformation that is actually performed is the application of rule ρ1 shown in Figure 4. In that case, the correctness formula is (∀x, y.lives_with(x, y) ⇒ lives_with(y, x)) ⇒(∀x, y.(lives_with(x, y) ∨(x = a ∧y = b) ∨(x = b ∧y = a)) ⇒(lives_with(y, x) ∨(x = b ∧y = a) ∨(x = a ∧y = b)) which is obviously valid. 3. APPLICATION As it is possible to prove that each one of the transformation rewrite rules is correct, their combination is correct as well. FIGURE 6 | Rules inserting the knowledge that Alice, who did not exist in the knowledge base, is a girl who lives with Bob. Person, the same transformation rewrite rule χ1 can be applied several times introducing in the action not only addC(a, Child), as shown in Figure 6, but also, addC(a, Female) and addC(a, Person) triggered by the first application of the rule. The fact that the rules are iteratively applied does not create a risk of infinite looping provided we assume that there is a mechanism to check that the rule does not already contain the added elementary actions, given that doing the same elementary action twice yields the same result as doing it only once. Similarly, in an actual execution, the rules that do not modify the transformation, e.g., χ0 would not be part Person, the same transformation rewrite rule χ1 can be applied several times introducing in the action not only addC(a, Child), as shown in Figure 6, but also, addC(a, Female) and addC(a, Person) triggered by the first application of the rule. The fact that the rules are iteratively applied does not create a risk of infinite looping provided we assume that there is a mechanism to check that the rule does not already contain the added elementary actions, given that doing the same elementary action twice yields the same result as doing it only once. Similarly, in an actual execution, the rules that do not modify the transformation, e.g., χ0 would not be part One of the key advantages of using abstract rules to represent the modification of the transformations is that it becomes possible to use the same rule for multiple transformations. In actual cases, the ontology is likely to contain many more axioms and, in particular, to contain a much more developed hierarchy of classes and properties. However, assuming that the ontology contains additional axioms, e.g., Girl ⊆Female and Child ⊆ May 2021 | Volume 4 | Article 660101 Frontiers in Big Data | www.frontiersin.org 5 Correctness of Knowledge Graph Update Brenas and Shaban-Nejad PhysicalAbuse ⊆Abuse to also add the fact that pa is an Abuse. We could also have decided to remove the axiom and the knowledge graph would have been consistent with the modified ontology. 3. APPLICATION ρ5 looks for a patient suffering from a given type of ACEs, denoted by ACEs0, that are not assigned to anyone and for a social worker with nine or fewer patients assigned to them. It then assigns the patient to the social worker. ρ6 does the same for psychologists. ρ7 and ρ8 assign the (possibly) remaining patients to the default options. ρ9 and ρ10 look for patients with a phone number or an email address, respectively, and assign them to a case worker. ρ11 and ρ12 request the hiring of a social worker or a psychologist, respectively, if it had not been requested before and at least one patient is assigned to the default option. of the system. We only show them to make our reasoning clearer and easier to understand. Hitherto, we have only added knowledge to the graph and not removed any. Removing knowledge is not practically much more difficult, at least as long as we keep working with less expressive axioms. Example 3.4. Figure 7 contains some transformation rules dealing with node label deletion. χ6 is similar to the rules in Figure 5 and doesn’t actually modify the transformation. On the other hand, rules χ7 and χ8 are dependent on the current content of the knowledge graph. Indeed, if C(i) is true, the axiom C ⊆D is no longer true after the application of delC(i, D). Hence the rule need not only to look at the ontological part of the knowledge graph but also at the graph itself. f p We chose to apply the strategy s ≡(ρ5⊕ρ6)∗; (ρ7⊕ρ8)∗; (ρ9⊕ ρ10)n; ρ∗ 11; ρ∗ 12. In order to be able to perform verification, all closures need to be annotated. We annotate all of them with φ, that is all invariants are the same as the pre- and post-conditions. (ρ9 ⊕ρ10)n denotes n-iterations of the strategy ρ9 ⊕ρ10. It is a proper strategy for any given n and the actual choice of n has no impact on the correctness of the specification so we use this construct to let an unspecified number of patients register for the study. ρ11 and ρ12 can only be applied at most once each. More elaborate strategy constructors can be defined to require that strategies are applied at most once, for instance, but we did not introduce them in this paper to keep things simpler. 3. APPLICATION FIGURE 7 | Examples of rules rewriting transformations when deleting the label of node. FIGURE 8 | A rule that adds the fact that has_father ⊆has_parent. PhysicalAbuse ⊆Abuse to also add the fact that pa is an Abuse. We could also have decided to remove the axiom and the knowledge graph would have been consistent with the modified ontology. As the last example, we will add a new axiom to the ontology. Until now, we have only used the left-hand side of the rules to look at specific instances, either of axioms, elementary actions or individual nodes and we only, perhaps, added a new elementary action to a given rule. When modifying the ontology, a new rule is added that will modify the graph. Example 3.6. Let us assume that we want to add the axiom has_father ⊆has_parent to the ontology. Rule ρ4 presented in Figure 8 is applied to the graph with Strategy ρ∗ 4. The correctness formula, in that case, is, after some simplification, (∀x, y. has_father(x, y) ⇒has_parent(x, y)) ⇒(∀x, y. has_father(x, y) ⇒has_parent(x, y)), an obvious tautology. Example 3.6. Let us assume that we want to add the axiom has_father ⊆has_parent to the ontology. Rule ρ4 presented in Figure 8 is applied to the graph with Strategy ρ∗ 4. The correctness formula, in that case, is, after some simplification, (∀x, y. has_father(x, y) ⇒has_parent(x, y)) ⇒(∀x, y. has_father(x, y) ⇒has_parent(x, y)), an obvious tautology. Example 3.7. Let us now consider the more elaborate example of Example . Let us define φ0 ≡ ∀x.Psychologist(x) ⇒∃≤5y.(Patient(y) ∧assigned_to(y, x)), φ1 ≡ ∀x.SocialWorker(x) ⇒ ∃≤10y.(Patient(y) ∧assigned_to(y, x)) and φ2 ≡ ∀x.(DefSocialWorker(x) ∨DefPsychologist(x) ∨ CaseWorker(x)) ⇒ FIGURE 7 | Examples of rules rewriting transformations when deleting the label of node. FIGURE 7 | Examples of rules rewriting transformations when deleting the label of node. ¬(SocialWorker(x) ∨Psychologist)). The precondition and the post-condition will then be φ ≡φ0 ∧φ1 ∧φ2. φ0 states that psychologists are assigned less than five patients, φ1 states that social workers are assigned <10 patients, φ2states that default psychologists and social workers and case workers do not count as psychologists or social workers (otherwise, they might not satisfy φ0 or φ1). The set of rules R contains the rules shown in Figure 9. Frontiers in Big Data | www.frontiersin.org 3. APPLICATION The annotated specification is thus s′ ≡{φ}(R, (ρ5 ⊕ρ6)∗{φ}; (ρ7 ⊕ ρ8)∗{φ}; (ρ9 ⊕ρ10)n; ρ∗ 11{φ}; ρ∗ 12{φ}){φ}. Up to now, we have modified the graph by adding and changing the labeling of the knowledge graph but we have not modified the ontology itself. It is worth pointing that the choices that we made when the transformation presented a risk of inconsistency always lead us to modify the graph and not the ontology. There is, however, no reason to think that when there is a conflict between the ontology and the content of the graph, the ontology is always to be considered correct. Example 3.5. In the first example we presented, we chose when adding the fact that pa was a PhysicalAbuse knowing that Giving the full proof that the specification is correct would be long and tedious. Instead, let us give an informal description of the May 2021 | Volume 4 | Article 660101 Frontiers in Big Data | www.frontiersin.org 6 Correctness of Knowledge Graph Update Brenas and Shaban-Nejad URE 9 | The rules used in Example 3.7. FIGURE 9 | The rules used in Example 3.7. Frontiers in Big Data | www.frontiersin.org May 2021 | Volume 4 | Article 660101 Correctness of Knowledge Graph Update Brenas and Shaban-Nejad FIGURE 10 | A schema of the recommender system (Brenas et al., 2019b). FIGURE 10 | A schema of the recommender system (Brenas et al., 2019b). definitions. Similarly, we have only looked at the easiest of the interactions between transformations and axioms. proof. Neither ρ11 nor ρ12 affect any of the predicates in φ thus one can ignore them. ρ9 and ρ10 only modify assigned_to(x, y) for y a case worker. From φ2, one gets that being a case worker excludes the possibility of being either a social worker or a psychologist which means that if φ is true after (ρ5 ⊕ρ6)∗; (ρ7 ⊕ρ8)∗, it will be true at the end of the execution. Similarly, ρ7 and ρ8 only modify the assignment to the default social worker and psychologist that, according to φ2, are not social workers or psychologists. Thus, one needs to prove that {φ}(R, (ρ5 ⊕ρ6)∗{φ}){φ} is correct. ρ5 only assigns a patient to a social worker that has nine or less and thus, after the assignment, they will only have ten or less. The same argument works for psychologists albeit with a different number of edges. 4. CONCLUSION Moreover, we have only presented logics with very little expressivity in this work to make it easier to follow and to avoid problems that arise at higher expressivity. However, it has been proved that the verification that underpins this method works for the whole expressivity of C2 (Brenas et al., 2018a). Moreover, OWL allows defining more complex axioms on properties, e.g., transitivity, that cannot be expressed in C2 but can be expressed in other decidable logics, such as the Guarded Fragment of first-order logic (Andréka et al., 1998) for which the same results apply (Brenas et al., 2018b). Extending the expressivity to full first order logic and beyond is much more difficult as satisfiability in first-order logic is undecidable and, as a result, so is our verification process. On the other hand, it is possible to restrict the specifications to less expressive logics. Finding the conditions on the logic and the change that can be performed to reduce the complexity of the verification process is under active study. The importance of the complexity problem is somewhat reduced by the fact that the complexity of the verification task is dependent on the size of the specification and not on the size of the data it represents. In this paper, we demonstrated the feasibility of using graph transformations for managing changes and modifications in knowledge graphs while maintaining their consistency. We used logically decorated graphs to represent the knowledge graph, graph transformations for the modifications and a Hoare-like approach to verification to prove the correctness of the transformations. Verification of graph transformations is an active field of computer science. Our approach is based on the method of Brenas et al. (2016b). Several other approaches exists including methods akin to model checking (Rensink et al., 2004) or the use of graph programming languages, such as GP2 (Wulandari and Plump, 2020). These methods have not been applied to knowledge graphs as far as we know. This is only the first step toward a comprehensive solution. An important limitation to the application of our method is the fact that not all currently existing knowledge graphs are equipped with ontologies. In the absence of an ontology, the whole problem is moot as there is nothing to be consistent with. Frontiers in Big Data | www.frontiersin.org 3. APPLICATION The specification s′ is thus correct. In particular, the rules that we have presented allow automating the process in the situation that we have presented but it is not hard to find examples where such automation is not feasible. When increasing the expressivity of the axioms, there are many situations where a non-trivial choice has to be made to decide which part of the knowledge is responsible for the inconsistency, and thus should be removed. Algorithms exist to do repairs (Bienvenu et al., 2016) that go much further than we did and integrating these algorithms into our method seems promising. That said, the verification process generates a counter model, which is a knowledge graph that invalidates the specification. This counter model can be used to decide the source of the error. REFERENCES Brenas, J. H., Shin, E. K., and Shaban-Nejad, A. (2019b). A hybrid recommender system to guide assessment and surveillance of adverse childhood experiences. Stud. Health Technol. Inform. 262, 332–335. doi: 10.5210/ojphi.v11i1.9694 Al-Manir, M. S., Brenas, J. H., Baker, C. J., and Shaban-Nejad, A. (2018). A surveillance infrastructure for malaria analytics: provisioning data access and preservation of interoperability. JMIR Public Health Surveill. 4:e10218. doi: 10.2196/10218 Brenas, J. H., Shin, E. K., and Shaban-Nejad, A. (2019c). An ontological framework to improve surveillance of adverse childhood experiences (ACES). Stud. Health Technol. Inform. 258, 31–35. doi: 10.3233/978-1-61499-959-1-31 Brenas, J. H., Strecker, M., Echahed, R., and Shaban-Nejad, A. (2018). Applied graph transformation and verification with use cases in malaria surveillance. IEEE Access 6, 64728–64741. doi: 10.1109/ACCESS.2018.2878311 Andréka, H., Németi, I., and van Benthem, J. (1998). Modal languages and bounded fragments of predicate logic. J. Philos. Logic 27, 217–274. doi: 10.1023/A:1004275029985 Felitti, V., Anda, R., Nordenberg, D., Williamson, D., Spitz, A., Edwards, V., et al. (1998). Relationship of childhood abuse and household dysfunction to many of the leading causes of death in adults: The adverse childhood experiences (ACE) study. Am. J. Prev. Med. 14, 245–258. doi: 10.1016/S0749-3797(98)00017-8 Barendregt, H. P., van Eekelen, M. C. J. D., Glauert, J. R. W., Kennaway, R., Plasmeijer, M. J., and Sleep, M. R. (1987). “Term graph rewriting,” in PARLE, Parallel Architectures and Languages Europe, Volume II: Parallel Languages, June 15–19, 1987, Proceedings (Eindhoven), 141–158. doi: 10.1007/3-540-17945-3_8 Gradel, E., Otto, M., and Rosen, E. (1997). “Two-variable logic with counting is decidable,” in Proceedings of 12th IEEE Symposium on Logic in Computer Science LICS ’97 (Warschau). doi: 10.1109/LICS.1997.614957 Bienvenu, M., Bourgaux, C., and Goasdoué, F. (2016). “Explaining inconsistency- tolerant query answering over description logic knowledge bases,” in Proceedings of the Thirtieth AAAI Conference on Artificial Intelligence, February 12–17, 2016 (Phoenix, AZ), 900–906. Hoare, C. A. R. (1969). An axiomatic basis for computer programming. Commun. ACM 12, 576–580. doi: 10.1145/363235.363259 Brenas, J. H., Al-Manir, M. S., Baker, C. J. O., and Shaban-Nejad, A. (2017). A malaria analytics framework to support evolution and interoperability of global health surveillance systems. IEEE Access 5, 21605–21619. doi: 10.1109/ACCESS.2017.2761232 Rensink, A., Schmidt, Á., and Varró, D. (2004). “Model checking graph transformations: a comparison of two approaches,” in Graph Transformations, eds H. Ehrig, G. Engels, F. Parisi-Presicce, and G. Rozenberg (Berlin; Heidelberg: Springer Berlin Heidelberg), 226–241. doi: 10.1007/978-3-540-30203-2_17 Brenas, J. H., Echahed, R., and Strecker, M. (2016a). 4. CONCLUSION That said, it is possible to start with an empty ontology and to use our method to provably make sure that a knowledge graph becomes consistent with it by defining rules that modify it. Among the possible applications of the research presented in this paper is the conception of a recommender system to assist in the detection, prevention and treatment of ACEs (Brenas et al., 2019b). Figure 10 shows a schema of We have presented a few transformation rewriting rules and we are working to formulate a formal framework for their May 2021 | Volume 4 | Article 660101 8 Correctness of Knowledge Graph Update Brenas and Shaban-Nejad AUTHOR CONTRIBUTIONS the recommender system’s components. The recommender needs to be able to update its knowledge about the circumstances and the health of the patients in a verifiably correct manner. JB and AS-N contributed equally to the research and writing of this paper. FUNDING The funding for this study has been provided by the University of Tennessee Health Science Center. The funding for this study has been provided by the University of Tennessee Health Science Center. The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation. Tennessee Health Science Center. REFERENCES “Ensuring correctness of model transformations while remaining decidable,” in Theoretical Aspects of Computing–ICTAC 2016–13th International Colloquium, October 24– 31, 2016, Proceedings (Taipei), 315–332. doi: 10.1007/978-3-319-4675 0-4_18 Wulandari, G. S., and Plump, D. (2020). “Verifying graph programs with first-order logic,” in Proceedings of the Eleventh International Workshop on Graph Computation Models, Online-Workshop, 24th June 2020, Volume 330 of Electronic Proceedings in Theoretical Computer Science, eds B. Hoffmann and M. Minas (Open Publishing Association), 181–200. doi: 10.4204/EPTCS.330.11 Zhang, L. (2002). Knowledge graph theory and structural parsing (Ph.D. thesis), University of Twente, Twente University Press, Enschede Wulandari, G. S., and Plump, D. (2020). “Verifying graph programs with first-order logic,” in Proceedings of the Eleventh International Workshop on Graph Computation Models, Online-Workshop, 24th June 2020, Volume 330 of Electronic Proceedings in Theoretical Computer Science, eds B. Hoffmann and M. Minas (Open Publishing Association), 181–200. doi: 10.4204/EPTCS.330.11 Brenas, J. H., Echahed, R., and Strecker, M. (2016b). “Proving correctness of logically decorated graph rewriting systems,” in 1st International Conference on Formal Structures for Computation and Deduction, FSCD 2016, June 22–26, 2016 (Porto), 14:1–14:15. Zhang, L. (2002). Knowledge graph theory and structural parsing (Ph.D. thesis), University of Twente, Twente University Press, Enschede Conflict of Interest: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Brenas, J. H., Echahed, R., and Strecker, M. (2018a). On the verification of logically decorated graph transformations. CoRR abs/1803.02776. Brenas, J. H., Echahed, R., and Strecker, M. (2018b). “Verifying graph transformations with guarded logics,” in 2018 International Symposium on Theoretical Aspects of Software Engineering, TASE 2018, August 29–31, 2018 (Guangzhou), 124–131. doi: 10.1109/TASE.2018.00024 Copyright © 2021 Brenas and Shaban-Nejad. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Brenas, J. H., Shin, E. K., and Shaban-Nejad, A. (2019a). Adverse childhood experiences ontology for mental health surveillance, research, and evaluation: Advanced knowledge representation and semantic web techniques. JMIR Mental Health 6:e13498. doi: 10.2196/preprints. REFERENCES 13498 May 2021 | Volume 4 | Article 660101 Frontiers in Big Data | www.frontiersin.org 9
https://openalex.org/W2030355576
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Construção e validação do instrumento "Inventário de problemas éticos na atenção primária em saúde"
Revista Bioética
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1. Doutor roquejunges@hotmail.com – Unisinos, São Leopoldo/RS, Brasil 2. Livre docente elma@usp.br – Universidade de São Paulo, São Paulo/SP, Brasil 3. Doutor mppatussi@unisinos.br – Unisinos, São Leopoldo/RS, Brasil 4. Doutoranda rafaelaschaefer@hotmail.com – Universidade Católica Portuguesa, Porto, Portugal 5. Doutoranda carliserdn@yahoo.com.br – Universidade Católica Portuguesa, Porto, Portugal. La construcción y validación del “Inventario de problemas éticos en la atención primaria de la salud”iili Identificar los conflictos éticos contribuye para mejorar la calidad de la atención. Este estudio tuvo como obje- tivo evaluar la validez de constructo y la consistencia interna del Inventario de Problemas Éticos en la Atención Primaria de la Salud. El instrumento, un cuestionario estructurado y cerrado, es resultado de una década de investigaciones sobre bioética en la atención primaria. El artículo enfoca la última etapa de validación. En el inicio de esta etapa, el instrumento contenía 41 elementos. Se lo ha aplicado a 237 profesionales de 12 centros de salud del Grupo Hospitalar Conceição (Porto Alegre/RS). Tras el análisis factorial exploratorio de las puntuaciones, se encontró seis dimensiones centrales con alto grado de fiabilidad y consistencia (KMO = 0,831, Bartlett p < 0,001, alpha 0,876), explicando el 61,4 % de la varianza. La versión validada del instrumento quedó con 6 factores y 24 ítems. El instrumento contribuirá para las investigaciones en bioética, pues posibili- ta estudios cuantitativos en grandes muestras para llevar a reconocerse los problemas éticos más frecuentes en atención primaria.ii Artigos de pesquisa Palabras-clave: Estudios de validación. Ética. Bioética. Atención primaria de salud. Solución de pr Resumo Identificar conflitos éticos contribui para melhorar a qualidade da assistência. O estudo objetivou verificar a validade de construto e consistência interna do “Inventário de problemas éticos na atenção primária em saú- de”. O instrumento, questionário estruturado e fechado, é fruto de uma década de pesquisas sobre bioética na atenção básica. O artigo enfoca a última etapa da validação. No início dessa fase, o instrumento continha 41 itens. Foi aplicado a 237 profissionais de 12 unidades de saúde do Grupo Hospitalar Conceição (Porto Alegre/RS). Após análise fatorial exploratória dos escores, obtiveram-se seis dimensões centrais com eleva- do grau de confiabilidade e consistência (KMO=0,831; Bartlett p<0,001; α geral 0,876), explicando 61,4% da variância. Ao final, o instrumento validado ficou com seis fatores e 24 itens. O instrumento poderá contribuir para pesquisas em bioética, com estudos quantitativos em grandes amostras, bem como propiciar o reconhe- cimento dos problemas éticos mais comuns na atenção básica. Palavras-chave: Estudos de validação. Ética. Bioética. Atenção primária à saúde. Resolução de problemas. Aprovação CEP/Grupo Hospitalar Conceição 09-156 Declaram não haver conflito de interesse. Construction and validation of the instrument “Inventory of ethical problems in primary health care” sível, bastante compreensível e de fácil aplicação. Na continuidade da validação, era preciso avaliar o construto do instrumento. Para validar a clareza, a facilidade de leitura e a confiabilidade do construto desenvolveu-se, entre 2006 e 2008, um estudo me- todológico 6. A validação da clareza e confiabilidade deu-se por meio de um painel de especialistas em saúde da família, com uso da técnica Delphi. Cada item do IPE-APS teve seu enunciado des- crito segundo a situação narrada pelos entrevista- dos do estudo, cujos resultados deram origem à lista de problemas constantes do inventário. Para cada item do IPE-APS solicitava-se aos especialistas do painel que avaliassem a congruência entre o enun- ciado do problema ético e a descrição da situação que o gerou. Havia espaço para que os especialistas sugerissem nova redação para o enunciado, se fosse o caso. O ponto de corte da congruência era 80%, sendo mantida a redação dos enunciados com valor igual ou superior a isso 6. Nessa perspectiva, desde 2000 temos estuda- do a temática da ética na APS. O primeiro estudo, entre 2000 e 2003, desenvolveu uma pesquisa qua- litativa com enfermeiros e médicos de equipes de saúde da família do município de São Paulo, objeti- vando reconhecer um perfil das questões éticas nes- sa nova forma de organização da APS no SUS. Como resultado, obteve-se uma lista de 41 problemas 1, que originaram a primeira versão do Inventário de problemas éticos na atenção primária (IPE-APS). Para a validação da facilidade de leitura usou-­ se o Índice de Facilidade de Leitura de Flesch-Kincaid (ILFK), disponível no Microsoft Windows Word. A redação final dos enunciados dos problemas éticos resultante da consulta ao painel de especialistas foi ajustada para uma facilidade de leitura compatível com uma escolaridade aproximada ao 7o ano (antiga 6a série) do ensino fundamental (leitura razoavel- mente fácil). A redação ajustada para cada item foi revista por uma professora de língua portuguesa, para verificar a adequação e correção da escrita. Com esse estudo metodológico fechou-se, em 2008, a 2a versão do IPE-APS 6. Entre 2004 e 2005, desenvolveu-se um segun- do estudo para reconhecer se os problemas aponta- dos no primeiro se repetiriam na vivência de outras equipes de saúde da família e se ainda haveria algo a acrescentar. Construction and validation of the instrument “Inventory of ethical problems in primary health care” Identifying ethical conflicts contributes to improve healthcare quality. This study aimed to evaluate content validity and verify internal consistency of the Inventory of Ethical Problems in Primary Health Care. The in- strument – a close and structured questionnaire – is a result of decades of researches on bioethics in primary health care. The article focuses on the last stage of validation. At the beginning of this stage the instrument had 41 items. It was applied to 237 professionals of 12 primary care centers at Grupo Hospitalar Conceição (Porto Alegre/RS). After the exploratory factor analysis, it resulted in six dimensions with high degree of reli- ability and consistency (KMO = 0.831, Bartlett p < 0.001; alpha 0.876), which explained 61.4 % of variance. At the end, the validated version of the instrument had 6 factors and 24 items. The instrument may contribute to researches in bioethics through the development of studies to recognize the most common ethical problems in primary care and to explore the influence of different contexts on ethical problems. Key words: Validation studies Ethics Bioethics Primary health care Problem solving Artigos de pesquisa Key words: Validation studies. Ethics. Bioethics. Primary health care. Problem solving. Declaram não haver conflito de interesse. Rev. bioét. (Impr.). 2014; 22 (2): 309-17 http://dx.doi.org/10.1590/1983-80422014222012 309 Construção e validação do instrumento “Inventário de problemas éticos na atenção primária em saúde” Construção e validação do instrumento “Inventário de problemas éticos na atenção primária em saúde” Construção e validação do instrumento “Inventário de problemas éticos na atenção primária em saúde” Construção e validação do instrumento “Inventário de problemas éticos na atenção primária em saúde” Investigações sobre os desafios éticos nos ser- viços de atenção à saúde podem levar os profissio- nais a refletir, deliberar e avaliar atitudes éticas nas práticas de saúde 1. Os problemas éticos são desafios que exigem deliberação pela melhor solução. Enten- didos como desafios, não podem ser resolvidos por meio de receitas prontas, mas exigem permanente criatividade, porque requerem respostas de longo alcance, que ultrapassem a solução de um caso parti- cular 2. No Sistema Único de Saúde (SUS), a Estratégia de Saúde da Família (ESF) vem reorganizando a Aten- ção Primária à Saúde (APS) por meio da efetivação dos princípios da longitudinalidade e da integralida- de. Tal fato reforça a necessidade de compromissos éticos das equipes, que têm de exercer nova prática marcada pela humanização, cuidado e cidadania 1. Construction and validation of the instrument “Inventory of ethical problems in primary health care” O estudo mostrou que a primeira ver- são do IPE-APS era de fácil compreensão e preen- chimento, contendo uma lista de problemas éticos da prática na APS suficientemente abrangente, não sendo necessário incluir novos exemplos 3. Artigos de pesquisa Até essa segunda versão o IPE-APS vinha sen- do validado na vertente qualitativa. Sua escala para registro da ocorrência dos problemas éticos era no- minal e não numérica. A partir de 2009, usando a segunda versão do IPE-APS, iniciou-se a validação por meio de técnicas quantitativas, para viabilizar a incorporação de uma escala do tipo Likert no instru- mento. Com isso, seria possível seu uso em estudos quantitativos, com amostras maiores. As pesquisas objetivaram verificar a validade de construto e a consistência interna do IPE-APS. O presente artigo descreve os resultados da última dessas pesquisas de validação do IPE-APS. De 2005 a 2009, no município de São Paulo, outros dois estudos qualitativos investigaram as si- tuações eticamente significativas vividas por enfer- meiros e médicos em serviços de APS não reorgani- zados pela ESF. Uma dessas pesquisas investigou as unidades básicas de saúde (UBS) tradicionais e a ou- tra enfocou os centros de saúde escola 4. Os resulta- dos comprovaram a abrangência da lista de proble- mas que compunha a primeira versão do IPE-APS. Um terceiro estudo desse mesmo período validou a sensibilidade do instrumento. Para essa etapa de validação foi desenvolvido um estudo com expertos da área de ética e bioética. O instrumento mostrou-­ se sensível, permitindo captar a variação de visão segundo o grupo em que era aplicado: profissionais da APS e especialistas em ética e bioética 5. Artigos de pesquisa Artigos de pesquisa Método Estudo transversal, realizado no Rio Grande do Sul, com profissionais de 12 unidades de saúde do Grupo Hospitalar Conceição (GHC), instituição pú- Com esses estudos, viu-se que a primeira versão do IPE-APS se mostrava abrangente, sen- Rev. bioét. (Impr.). 2014; 22 (2): 309-17 http://dx.doi.org/10.1590/1983-80422014222012 310 Construção e validação do instrumento “Inventário de problemas éticos na atenção primária em saúde” blica federal vinculada ao Ministério da Saúde, refe- rência no atendimento do SUS. O Grupo conta com uma equipe de 7.913 profissionais e abrange quatro hospitais (Conceição, Criança Conceição, Cristo Re- dentor e Fêmina), 12 postos de saúde do Serviço de Saúde Comunitária, três centros de atenção psicos- social (Caps) e o Centro de Educação Tecnológica e Pesquisa em Saúde, a Escola GHC. É nacionalmente reconhecido como a maior rede pública de hospitais do Sul do Brasil, com 100% de atendimento SUS 7. tuação enunciada no item. Caso contrário, tinha que assinalar com que frequência encontrava o proble- ma em seu trabalho na APS: nunca (1); raramente (2); frequentemente (3); sempre (4). Registraram-se, também, algumas caracterís- ticas dos respondentes: socioeconômicas, especial- mente a escolaridade; demográficas (sexo, cor ou raça e estado civil); fatores relacionados ao processo de trabalho (profissão, tempo de formação, tempo de trabalho na APS e tempo de trabalho na unidade de saúde atual). O trabalho de campo teve início em julho de 2011 com um estudo piloto, realizado na unidade de saúde Conceição, que incluiu cerca de 60 profis- sionais. O propósito era conhecer a realidade in loco para organizar o trabalho de campo e, também, ob- servar a compreensibilidade do instrumento pelos profissionais durante o seu preenchimento, vez que só havia sido utilizado em estudos no município de São Paulo. O Epidata versão 3.1 foi utilizado para a di- gitação dos dados e o software Statistical Package for the Social Sciences (SPSS) versão 12.0, para a análise. Com o objetivo de avaliar a adequação dos dados à análise fatorial, usou-se o teste de Kaiser-­ Meyer-Olkin (KMO). Para a validação do constructo fez-se uso da análise de componentes principais e a rotação varimax. Método Para tanto, foram seguidos os pas- sos propostos por Hair JF, Anderson RE, Tatham RL e Black WC 10: formulação do problema; construção da matriz de correlação; determinação do método de análise fatorial; determinação do número de fato- res; rotação dos fatores; interpretação dos fatores; cálculo das cargas fatoriais ou escolha de variáveis substitutas, e determinação do ajuste do modelo. A coleta de dados ocorreu entre agosto e de- zembro de 2011, aproveitando-se as reuniões sema- nais das equipes. Os profissionais eram convidados a participar de forma voluntária, formando uma amostra por conveniência. Após os esclarecimen- tos sobre a pesquisa e a liberdade de participação, todos os presentes à reunião recebiam o IPE-APS, com as instruções para seu preenchimento. Ao final, recolhiam-se todos os instrumentos distribuídos, estivessem ou não preenchidos. Como não havia identificação do respondente se preservava o anoni- mato dos incluídos no estudo e também dos que se recusaram a participar, já que a retirada dos instru- mentos em branco não era feita no campo. Para encontrar a melhor solução em termos de números de fatores utilizaram-se como critérios: au- tovalor maior ou igual a 1, mínimo de três itens por fator, e coerência com a teoria que fundamentou a construção do instrumento em todos os estudos: a bioética deliberativa de Diego Gracia. Os critérios de remoção de itens foram: aumento de alpha após a remoção do item; item carregando vários fatores ao mesmo tempo, e remoção do item cujo conteúdo não fosse coerente com o construto. Para avaliar a consistência interna da escala total e sua subescala utilizou-se o alpha de Cronbach 11. Artigos de pesquisa Artigos de pesquisa A amostra totalizou 237 profissionais. Para o procedimento de análise fatorial exploratória, au- tores mais rigorosos, como Dassa 8, sustentam que o tamanho ideal da amostra é de, no mínimo, dez sujeitos por item do inventário ou um total de pelo menos 250 sujeitos. Outros autores, como Pestana e Gageiro 9, propõem, no mínimo, cinco sujeitos por questão em inventários com mais de 15 itens, considerando-se um mínimo de 100 sujeitos. Frente a isso, consideramos a amostra do presente estudo suficiente para as análises propostas. Artigos de pesquisa Artigos de pesquisa A pesquisa foi aprovada pelo Comitê de Ética em Pesquisa do Grupo Hospitalar Conceição e todos os participantes assinaram o termo de consenti- mento livre e esclarecido. Resultados A versão do IPE-APS submetida à validação quantitativa continha os 41 itens da segunda ver- são da validação qualitativa, com problemas éticos em três âmbitos relacionais da atenção à saúde: usuário-profissional, equipes de saúde da família e sistema de saúde 1. A cada item os respondentes po- diam expressar sua visão sobre o tema numa escala que variava de zero a quatro. O zero significava que o respondente não considerava problema ético a si- Dentre outros profissionais de saúde das equi- pes de saúde da família, a amostra de 237 profissionais incluía médicos (14%), agentes comunitários de saúde (11%), auxiliares e/ou técnicos em enfermagem (10%) e enfermeiros (9%). Predominou o sexo feminino (79%), 82% se consideravam brancos, 50% eram sol- teiros e 60% apresentavam idade entre 21 e 40 anos. http://dx.doi.org/10.1590/1983-80422014222012 Rev. bioét. (Impr.). 2014; 22 (2): 309-17 311 Construção e validação do instrumento “Inventário de problemas éticos na atenção primária em saúde” Construção e validação do instrumento “Inventário de problemas éticos na atenção primária em saúde” Construção e validação do instrumento “Inventário de problemas éticos na atenção primária em saúde” A análise dos dados considerou as respostas dos 237 profissionais participantes. Com o intuito de avaliar a estrutura geral dos dados, rodou-se a análise no SPSS de forma aberta, ou seja, sem de- limitar previamente a quantidade de fatores, com rotação varimax. O resultado dessa análise indicou a existência de 10 diferentes fatores, nos quais índice KMO=0,847 e Bartlett p<0,001. A variância explica- da nesta solução era de 63,5% e o alpha geral 0,921. Essas medidas indicaram que os resultados eram satisfatórios, ou seja, mostraram a adequação dos dados para se proceder ao modelo exploratório de análise fatorial. Agrupa problemas éticos referentes à: carência de condições para os atendimentos; falta de condições para a realização de visitas domiciliares; deficiên- cias do serviço de retaguarda para a remoção de pacientes; dificuldades no sistema de referência e contrarreferência; retorno e confidencialidade dos resultados de exames laboratoriais e; excesso de fa- mílias adscritas a cada equipe na ESF. Esse domínio do IPE-APS traz a questão dos aspectos diretamente relacionados à organização e ao funcionamento dos serviços como fonte de problemas éticos para os profissionais de saúde na ESF. Resultados O fator ‘longitudinalidade’ contém quatro itens que tratam das questões relacionadas à: con- tinuidade de tratamento; recusa em seguir a indica- ção médica; prescrição de medicamento que o usuá­ rio não terá dinheiro para comprar e; dificuldade de cumprir na prática as responsabilidades de cada profissional da equipe. Esse domínio do IPE-APS en- globa os problemas éticos decorrentes da prolonga- da relação que se estabelece entre o profissional e o usuário. O alpha de Cronbach desse fator foi 0,70. Após a verificação da adequação dos dados, para a sequência da análise foram retirados os itens que, ao mesmo tempo, apresentavam dois ou mais fatores ainda que com baixa comunalidade. Reti- raram-se, um a um, seis itens, o que aumentou a variân­cia para 64,4%. Após a retirada desses itens, a análise gerava nove fatores. Três fatores tinham apenas dois itens, o que não é recomendável na validação, segun- do autores como Tabachnick e Fidell 11. Portanto, optou-se por retirar mais seis itens. Com isso, a ex- plicação da variância diminuiu para 59,6%. Não se esperava esse comportamento da variância com a remoção dos itens, mas, apesar disso, devido à ne- cessidade de eliminar fatores que continham ape- nas dois itens, optou-se pela retirada. No fator ‘prática das equipes’ estão quatro itens que expressam problemas éticos decorren- tes da fragmentação do trabalho das equipes e a dificulda­de de exercer a prática interdisciplinar. Esse domínio trata da: falta de respeito entre os mem- bros da equipe; falta de colaboração de uma equipe com a outra; profissionais que não apresentam per- fil para trabalhar na ESF e; profissionais que atuam com falta de compromisso e envolvimento. O alpha de Cronbach desse fator foi 0,76. Artigos de pesquisa Ao se analisar a consistência teórica, foram encontrados três itens cujos problemas éticos enun- ciados não faziam sentido nos fatores onde se aloca- ram. Também se optou por sua retirada. Obteve-se, assim, a explicação de 61,4% da variância em um modelo com seis fatores e 24 itens. O índice KMO ficou em 0,831, Bartlett p<0,001 e alpha geral de 0,876 (tabela 1). Esse arranjo de itens e fatores foi considerado a melhor solução de análise, pois com- binou importantes resultados estatísticos e agrupou os problemas éticos de forma apropriada do ponto de vista teórico 11. Três itens formam o fator ‘perfil profissional’, com alpha de Cronbach de 0,72. Discussão médico generalista ou equipe de saúde, nos múlti- plos episódios de doenças e cuidados de promoção e rea­bilitação da saúde. Para essa continuidade da atenção são imprescindíveis a existência e o reco- nhecimento de uma fonte regular de cuidados de atenção primária, o estabelecimento de vínculo terapêutico duradouro entre os pacientes e os pro- fissionais de saúde da equipe local e a continuida- de informacional 24. Nesses pontos concentram-se, também, os principais problemas éticos relaciona- dos à longitudinalidade. Como resultado de mais de uma década de pesquisas explorando a interface da bioética e aten- ção básica, logrou-se construir e validar um instru- mento para inventariar problemas éticos na atenção primária à saúde. A aplicação do IPE-APS permite fazer uma ‘epidemiologia’ 15 dos problemas éticos na visão dos profissionais de saúde que atuam na atenção primária. Mas, ultrapassa a contabilização porque pode se prestar à mediação da reflexão so- bre as questões éticas para a melhoria dos serviços de saúde. O terceiro fator, ‘prática das equipes’, corrobora estudos que apontaram deficiências na responsabili- dade coletiva no trabalho de equipe na ESF, pois os profissionais fragmentam em atuações isoladas o que deveria ser um saber coletivamente construído 25. Para se alcançar os objetivos da ESF é necessário o efe- tivo trabalho em equipe, com todos atuando em prol do mesmo objetivo. Nas equipes de saúde, cada pro- fissional exerce sua profissão no bojo de um trabalho coletivo, cujo resultado final depende da contribuição das diferentes áreas do saber à assistência 12. Os resultados do presente estudo validaram o IPE-APS porque mostraram que o instrumento apresenta homogeneidade e consistência interna, com congruência dos itens em cada fator e com o todo 16. A variância total explicada foi aceitável. Ape- nas 38,6% da variância permaneceu inexplorada 11. Além das medidas estatísticas satisfatórias, houve importante coerência teórica dos fatores resultan- tes da análise, segundo a literatura revisada 12,17. O ‘perfil profissional’, quarto fator, vem ao encontro das evidências de estudos com gestores e trabalhadores do SUS, das distintas esferas de go- verno, ao mostrarem que, da mesma forma que o desempenho e a gestão dos recursos humanos, a formação dos profissionais afeta, profundamente, a qualidade dos serviços e o grau de satisfação dos usuários 26,27. O setor público tem dificuldade para contratar profissionais com perfil adequado ao que se pretende e se espera para a APS. Discussão No processo de formação dos profissionais, apesar dos recentes es- forços de mudança, especialmente com a expansão das horas de estágio na saúde da família, persiste o distanciamento em relação às demandas e necessi- dades do SUS, com dificuldades para a integração de conhecimentos clínicos e da saúde coletiva 12. O fator com maior percentual de variância ex- plicada foi ‘gestão da atenção primária’, pois, inde- pendentemente do número de fatores retidos, este sempre se agrupava como o primeiro. Isso provavel- mente decorre da importância dessa questão para a APS, especialmente no SUS, no qual se vem propon- do que esse nível da atenção seja a porta de entrada do Sistema e, ao mesmo tempo, coordenadora do cuidado pelos diversos pontos da rede de atenção à saúde. Os problemas éticos relacionados à dimen- são da gestão da APS guardam relação direta com a ética na gestão dos serviços de saúde, deixando patente a dificuldade de separar a ética dos cuida- dos de saúde da ética na administração em saúde 18. Artigos de pesquisa Artigos de pesquisa Artigos de pesquisa Diversos estudos têm evidenciado a existên- cia de problemas relacionados à gestão do SUS 19-21. Cada vez mais os serviços de saúde requerem dos municípios o bom desempenho da capacidade de gestão, que há de se voltar para a mudança posi- tiva nos indicadores de saúde da população. Com isso, ganha importância a figura do gestor e de suas decisões político-gerenciais na efetividade e eficiên- cia do SUS. Os profissionais das equipes da ESF e os gestores devem guiar sua prática pelo princípio da responsabilidade ética 22. O fator ‘privacidade’ revela características pró- prias da APS, pois a casa dos usuários torna-se exten- são do consultório. A relação deixa de ser individual (médico-paciente) para se tornar coletiva (equipe de saúde-família), enriquecendo a discussão de um tó- pico essencial à bioética, a privacidade das pessoas autônomas, com os problemas específicos e peculia- res deste nível da atenção. A privacidade é um prin- cípio derivado da autonomia e engloba a intimidade, a vida privada e a honra das pessoas. No trabalho em equipe multiprofissional, a troca de informações é fundamental para a boa qualidade na assistência. Porém, as informações para os membros das equipes hão de se limitar às necessárias para cada um realizar suas atividades em benefício do usuário 28. Construção e validação do instrumento “Inventário de problemas éticos na atenção primária em saúde” Construção e validação do instrumento “Inventário de problemas éticos na atenção primária em saúde” Resultados São problemas éti- cos relativos ao perfil atitudinal do profissional na APS, reorganizada ou não pela ESF: pré-julgamento de usuários e familiares; falta de respeito e prescri- ções inadequadas. Artigos de pesquisa Artigos de pesquisa O quinto fator, ‘privacidade na atenção primária à saúde’, compreende três itens, que trazem aspectos próprios deste tema ético no contexto da APS, onde os domicílios e a comunidade são extensões do con- sultório. O fator teve alpha de Cronbach igual a 0,70. Os fatores podem ser tidos como categorias de análise ou, ainda, domínios de avaliação do IPE-APS. Eles agruparam os problemas éticos na APS por fre- quência e por suas características, os que mais acon- tecem e de que tipo são, com base em publicações sobre atenção básica 12: 1) Gestão da atenção primá- ria; 2) Longitudinalidade; 3) Prática das equipes; 4) Perfil profissional; 5) Privacidade na atenção primá- ria à saúde e; 6) Sigilo profissional (Tabela 1 – Anexo). O fator ‘sigilo profissional’ teve alpha de Cron- bach igual a 0,64 e agrupou quatro itens relativos aos problemas éticos nas informações sobre a saú- de dos usuários e o compartilhamento destas entre profissionais, usuários e familiares. Há consistência interna das dimensões resul- tantes da análise dos dados, com índices alpha de Cronbach 13,14 que variaram de desejável (α=0,85) a aceitável (α=0,64). O domínio ‘gestão da atenção primária’ con- tém seis itens, com alpha de Cronbach igual a 0,854. http://dx.doi.org/10.1590/1983-80422014222012 Rev. bioét. (Impr.). 2014; 22 (2): 309-17 312 Discussão A longitudinalidade do cuidado é o segundo fator do IPE-APS e pode ser entendido como carac- terística central e própria da atenção primária. Para Starfield 23, longitudinalidade refere-se ao acom- panhamento do paciente, ao longo do tempo, por http://dx.doi.org/10.1590/1983-80422014222012 Rev. bioét. (Impr.). 2014; 22 (2): 309-17 313 Construção e validação do instrumento “Inventário de problemas éticos na atenção primária em saúde” Construção e validação do instrumento “Inventário de problemas éticos na atenção primária em saúde” Construção e validação do instrumento “Inventário de problemas éticos na atenção primária em saúde” Construção e validação do instrumento “Inventário de problemas éticos na atenção primária em saúde” No sexto fator, ‘sigilo profissional’, levanta-se que a questão do segredo não está necessariamen- te vinculada ao contato direto entre informante e ouvinte. Em função do atendimento aos usuários e famílias, a informação pode ser obtida por uma ou mais pessoas e a confidencialidade deveria ser pre- servada, como respeito a um direito do usuário 29. Estudo brasileiro, realizado por Fortes e Spinetti 30, constatou que os agentes comunitários de saúde preocupam-se com o princípio ético da privacidade e com a necessidade de manter o sigilo, como obri- gação ética dos profissionais de saúde. sigilo profissional que deverão observar como mé- dicos, mas reconhecem ter dificuldades para definir as situações nas quais é necessário partilhar infor- mações e quando estas devem ser mantidas em se- gredo 33. Claro está que a troca de informações entre usuário e profissional depende diretamente do cli- ma de confiança que perpassa a relação clínica e o acolhimento do usuário no serviço 34. Estudo com mulheres portadoras de HIV, em uma região do município de São Paulo, mostrou que elas revelam sua condição para a equipe de saúde da família somente quando estabelecem vínculo e confiança com os profissionais. Ao contrário, quan- do sentem medo e insegurança devido à alguma ati- tude dos profissionais ou não confiam que o sigilo sobre sua condição será mantido, não revelam seu diagnóstico à equipe da atenção primária 35. O vín- culo, a confiança e acolhimento na relação dos ser- viços e profissionais com os usuários e famílias são elementos fundamentais para a reflexão e condução das questões éticas sobre sigilo e privacidade. Discussão Ressalte-se que os últimos dois fatores guar- dam semelhanças entre si, pois os termos ‘sigilo’ e ‘privacidade’ se confundem e os problemas éticos descritos em ambos os domínios se entrelaçam na assistência, podendo ser diferentemente interpre- tados pelos profissionais – talvez por isso tenham apresentado os menores índices de alpha de Cron- bach (0,70 e 0,64, respectivamente). De fato, a proposta do SUS de trabalho em equipe para a atenção primária, especialmente com a Estratégia Saúde da Família, traz questões éticas sobre o sigilo e a privacidade que requerem apro- fundamento das reflexões para chegarmos a res- postas que respeitem a dignidade e autonomia dos usuários dos serviços. Entretanto, talvez a confusão que se manifestou na análise desses itens no instru- mento seja reflexo de que usuários e profissionais ainda estão atônitos com a capilaridade propor- cionada pela ESF, onde equipes e profissionais pe- netram na privacidade dos lares, na intimidade da dinâmica familiar. Referências 1. Zoboli ELCP. Bioética e atenção básica: um estudo de ética descritiva com enfermeiros e médicos do Programa Saúde da Família. [tese]. São Paulo: USP; 2003.i 2. Gracia D. Ethical case deliberation and decision making. Med Health Care Philos. 2003;6(3):227- 33. 315 22 (2): 309-17 Artigos de pesquisa 3. Silva LT, Zoboli ELCP, Borges ALV. Bioética e atenção básica: um estudo exploratório dos problemas éticos vividos por enfermeiros e médicos no PSF. Cogitare Enferm. 2006;11(2):133-42. i 4. Zoboli ELCP Relación clínica y problemas éticos en atención primaria, São Paulo, Brasil. Aten Prim. 2010;42(8):406-1.ii 5. Silva LT, Zoboli ELCP. Problemas éticos na atenção primária: a visão de especialistas e profissionais. Revista Brasileira de Bioética. 2007;3(1):27-39. i 6. Silva LT. Construção e validação de um instrumento para mensuração de ocorrência de problema ético na atenção básica [dissertação] São Paulo: USP; 2008 i 6. Silva LT. Construção e validação de um instrumento para mensuração de ocorrência de problema i i 6. Silva LT. Construção e validação de um instrumento para mensuraçã ético na atenção básica. [dissertação]. São Paulo: USP; 2008. 6. Silva LT. Construção e validação de um instrumento para mensuração de ocorrência de problema ético na atenção básica. [dissertação]. São Paulo: USP; 2008. i 7. Grupo Hospitalar Conceição. Atenção à saúde. [Internet]. (acesso 24 jun. 2012). Disponível: http://www.ghc.com.br/default.asp?idMenu=atencao_saudeiii 8. Dassa C. Analyse multidimensionnelle exploratoire et confirmative. Montreal: Université Montréal; 1999. 9. Pestana MH, Gageiro JG. Análise de dados para ciências sociais: a complementaridade do SPSS. 3a ed. Lisboa: Silabo; 2003. 10. Anderson RE, Tatham RL, Black B. Multivariate data analysis. In: Hair JF, colaborador. 5th ed. New Jersey: Prentice Hall; 1998. i 11. Tabachinick BG, Fidell LS. Using multivariate statistics. 4th ed. San Francisco: Allyn and Bacon; 2001. 12. Brasil. Conselho Nacional de Secretários de Saúde. Atenção primária e promoção da saúde. Brasília: Conass; 2011.fi 13. Cronbach LJ. Coefficient alpha and the internal structure of tests. Psychometrika. 1951;16(3):297- 334. 14. Cronbach LJ, Meehl P. Construct validity in psychological tests. Psychological Bulletin. 1955;52(4):281-302. 15. Fetters MD, Brody H. The epidemiology of bioethics. J Clin Ethics. 1999;10(2):107-15. Psicometria: teoria dos testes na psicologia e educação. Petr 17. Brasil. Portaria no 2.488, de 21 de outubro de 2011. Aprova a política nacional de atenção básica, estabelecendo a revisão das diretrizes e normas para organização da atenção básica, para a estratégia de saúde da família (ESF) e o programa de agentes comunitários de saúde (PACS). Considerações finais 2014; 22 (2): 309-17 314 Construção e validação do instrumento “Inventário de problemas éticos na atenção primária em saúde” estatística. Teoricamente, ancora-se na bioética de- liberativa de Diego Gracia. Após esta última pesqui- sa de validação do IPE-APS, com a qual chegamos a uma terceira versão do instrumento, concluímos que ele possibilita: traçar perfis confiáveis das ques- tões éticas na APS; desencadear a reflexão das equi- pes e profissionais para a reformulação de atitudes pe­ssoais e processos de trabalho. tados para verificar se há influência de fatores cultu- rais, locais, sociais, de organização dos serviços de atenção primária nos problemas éticos vivenciados e identificados pelas equipes, podendo se aquilatar a interferência desses fatores, em caso positivo. Esses estudos também poderão indicar se há diferenças locais e regionais significativas no perfil de problemas éticos da atenção primária. Com isso, não se defende a mera descrição dos problemas éti- cos, mas sim sistematizar o reconhecimento da situ- ação, com a geração de evidências, para direcionar ações de transformação da prática da atenção pri- mária no sentido de torná-la mais ética, humanizada e cidadã. Localizando os pontos frágeis, no sentido ético, da atuação das equipes de atenção primária, poderá se dirigir a formação permanente para os tó- picos e questões mais relevantes e frequentes em cada realidade. Com o IPE-APS abrem-se caminhos para no- vas pesquisas na interface da bioética com a aten- ção primária à saúde. A relevância do instrumento é possibilitar a realização de estudos com amostras representativas de populações profissionais para verificar a potencialidade de generalização dos pro- blemas indicados no IPE-APS. Ademais, o uso de um instrumento validado em diferentes regiões, ou seja, sua aplicação em estudos com múltiplos sítios para coleta de dados, permitirá a comparação dos resul- Os vários projetos desenvolvidos desde o primeiro estudo em 2000 contaram com financiamento do CNPq, Fapesp e Capes sob a forma de auxílio à pesquisa e bolsas iniciação científica, mestrado, estágio pós-doutoral e produtividade. Considerações finais O IPE-APS é um instrumento original e inova- dor para a proposta de desenvolver pesquisas em bioética com o intuito de aprofundar a reflexão acer- ca dos desafios éticos na prática profissional cotidia- na dos serviços de saúde. Desconhece-se, até o mo- mento, a existência de instrumentos semelhantes, validados para medir o mesmo construto. Por isso, o IPE-APS é importante ferramenta na melhoria da atenção à saúde. Ele facilitará a realização de estu- dos extensos, com grandes amostras, o que, por sua vez, também contribuirá para seguir na validação do próprio instrumento. A aplicação de um mesmo instrumento validado em diferentes locais facilita a comparação dos achados, desde que respeitadas as questões da adaptação cultural. Artigos de pesquisa Estudo de Seoane e Fortes 31 mostra divergên- cias nas opiniões dos usuários quanto às informa- ções sobre sua saúde e vida familiar que repassam ao agente comunitário de saúde. Alguns cogitam limitar as informações, não confiando ao agente sequer itens referentes a sua doença. Porém, há usuários que afirmam compartilhar tudo o que diz respeito a sua saúde, conscientes de que as informa- ções serão levadas à equipe. Apesar de se perpetua­ rem na prática cotidiana da atenção primária situa- ções de desrespeito à confidencialidade, as equipes de saúde consideram que a preservação do sigilo e privacidade dos usuários é elemento chave para ofertar um serviço de qualidade e humanizado 32. Artigos de pesquisa Artigos de pesquisa A aplicabilidade do IPE-APS mostrou-se possí- vel em diferentes circunstâncias e locais de trabalho da atenção primária, sendo um bom recurso para pesquisadores, profissionais e gestores obterem in- formações sobre o perfil de problemas éticos na vi- são das equipes dos serviços, orientando o trabalho de comitês de ética, comissões de bioética e progra- mas de educação continuada para a realidade local. A perplexidade de todos os envolvidos nessa proposta de trabalho coletivo reflete-se na forma- ção dos futuros profissionais. Estudantes de medici- na reconhecem que a confidencialidade da informa- ção na sua experiência de aprendizagem na atenção básica é ponto essencial no desenvolvimento do O IPE-APS é um instrumento elaborado com um construto emanado da realidade do SUS e va- lidado por meio de pesquisas qualitativas e quanti- tativas que lançaram mão de instrumentais da aná- lise de discurso, análise de conteúdo, psicometria, http://dx.doi.org/10.1590/1983-80422014222012 Rev. bioét. (Impr.). Os vários projetos desenvolvidos desde o primeiro estudo em 2000 contaram com financiamento do CNPq, Fapesp e Capes sob a forma de auxílio à pesquisa e bolsas iniciação científica, mestrado, estágio pós-doutoral e produtividade. Referências Brasília; 2011. http://dx.doi.org/10.1590/1983-80422014222012 Rev. bioét. (Impr.). 2014; 22 (2): 309-17 315 Construção e validação do instrumento “Inventário de problemas éticos na atenção primária em saúde” 18. Silva JA, Dalmaso ASW. Agente comunitário de saúde: o ser, o saber, o fazer. Rio de Janeiro: Fiocruz; 2002. p. 240. 19. Serra CG, Rodrigues PHA. Avaliação da referência e contrarreferência no programa saúde da família na região metropolitana do Rio de Janeiro (RJ, Brasil). Ciênc. & Saúde Col. 2010;15(3):3.579-86. 20. Mendes EV. A atenção primária à saúde no SUS. Fortaleza: Escola de Saúde Pública do Ceará; 2002.ii 21. Paim JS, Teixeira CF. Configuração institucional e gestão do Sistema Único de Saúde: problemas e desafios. Ciênc. & Saúde Col. 2007;12(Supp):1.819-29.iii 22. Amorim AG, Souza ECF. Problemas éticos vivenciados por dentistas: dialogando com a bioética para ampliar o olhar sobre o cotidiano da prática profissional. Ciênc. & Saúde Col. 2010;15(3):869- 78. 23. Starfield B. Atenção primária: equilíbrio entre necessidades de saúde, serviços e tecnologia. Brasília: Unesco; 2002. 24. Haggerty JL, Reid RJ, Freeman GK, Starfield BH, Adair CE, McKendry R. Continuity of care: a multidisciplinary review. BMJ. 2003;327(7.425):1219-21. DOI: http://dx.doi.org/10.1136/ bmj.327.7425.1219 25. Pedrosa JIS, Teles JBM. Consenso e diferenças em equipes do programa de saúde da família. Rev. Saúde Pública. 2001;35(3):303-11. 26. Nogueira R. Avaliação de tendências e prioridades sobre recursos Opas; 2002. (Rede Observatório de Recursos Humanos de Saúde).tt 26. Nogueira R. Avaliação de tendências e prioridades sobre recursos humanos de saúde. Brasília: Opas; 2002. (Rede Observatório de Recursos Humanos de Saúde).tti 26. Nogueira R. Avaliação de tendências e prioridades sobre recursos humanos de saúde. Brasília: Opas; 2002. (Rede Observatório de Recursos Humanos de Saúde).tt 27. Cotta RMM, Morales MSV, Gonzáles AL, Ricos JAD, Cotta Filho JS. Obstáculos e desafios da saúd pública no Brasil. Rev Hospital Clínicas de Porto Alegre. 2002;22(1):25-32.ii 28. Fortes PAC, Martins CL. A ética, a humanização e a saúde da família. Rev. Bras. Enferm. 2000;53(n. esp):31-3. 29. Francisconi CF, Goldim JR. Aspectos bioéticos da confidencialidade e privacidade. In: Costa SIF, Oselka G, Garrafa V, coordenadores. Iniciação à bioética. Brasília: Conselho Federal de Medicina; 1998. p. 269-84. p 30. Fortes CAP, Spinetti RS. O agente comunitário de saúde e a privacidade das informações dos usuários. Cad. Saúde Pública. 2004;20(5):1.328-33. 31. Seoane AF, Fortes PAC. A percepção do usuário do programa saúde da família sobre a privacidade e a confidencialidade de suas informações. Saúde Soc. 2009;18(1):42-9. 32. Bellenzani R, Mendes RF. Referências Sigilo na atenção em DST/Aids: do consultório aos processos organizacionais. Polis e Psique. 2011;1(3):140-65.i 33. Ferreira RC, Silva RF, Zanolli MB, Varga CRR. Relações éticas na atenção básica em saúde: a vivência dos estudantes de medicina. Ciênc. Saúde Coletiva. 2009;14 (1 suppl): 1.533-40. 34. Teixeira RR. O acolhimento num serviço de saúde entendido como uma rede de conversações. In: Pinheiro R, Mattos RA, organizadores. Construção da integralidade: cotidiano, saberes e práticas em saúde. Rio de Janeiro: Abrasco; 2003. p. 89-111.i 35. Ferreira FC, Nichiata LYI. Mulheres vivendo com Aids e os profissionais do programa saúde da família: revelando o diagnóstico. Rev. Esc. Enferm. USP. 2008;42(3):483-9. Participação dos autores José Roque Junges: coordenador do estudo em Porto Alegre, que constituiu a última fase de validação do IPE-APS. Elma Lourdes Campos Pavone Zoboli: desenvolveu o estudo original que identificou os problemas éticos que compõem o IPE-APS e orientou as pesquisas que compõem as etapas anteriores de validação do instrumento. Marcos Paschoal Patussi: pesquisador responsável pelo braço quantitativo do estudo de Porto Alegre, para validação final e consistência interna do instrumento. Rafaela Schaefer e Carlise Rigon Della Nora: realizaram os trabalhos de campo, estruturação dos bancos de dados e análise dos dados. Todos os autores contribuíram igualmente para a elaboração e revisão final do artigo. Artigos de pesquisa Artigos de pesquisa http://dx.doi.org/10.1590/1983-80422014222012 Rev. bioét. (Impr.). 2014; 22 (2): 309-17 316 Construção e validação do instrumento “Inventário de problemas éticos na atenção primária em saúde” Construção e validação do instrumento “Inventário de problemas éticos na atenção primária em saúde” Anexo Tabela 1. Fatores, itens, índices de confiabilidade dos fatores e cargas fatoriais dos itens Itens Cargas fatoriais h2 1 2 3 4 5 6 Fator 1. Gestão da atenção primária (α=0,85) 40 A UBS não tem condições para realizar atendimentos de urgência 0,567 0,804 39 A UBS não oferece às equipes de saúde da família as condições para apoiar a realização de visitas domiciliares 0,581 0,791 41 Não há retaguarda de serviço de remoção, na UBS 0,479 0,766 37 Há dificuldades no sistema de referência e contrarreferência para a realização de exames complementares 0,555 0,700 38 Há dificuldades quanto ao retorno e à confiabilidade dos resultados dos exames laboratoriais 0,566 0,680 33 Há um excesso de famílias adscritas para cada equipe da ESF 0,557 0,671 Fator 2. Longitudinalidade (α=0,70) 8 Os profissionais sentem-se impotentes para convencer o usuário a dar continuidade ao tratamento 0,454 0,755 17 Usuários se recusam a seguir indicações médicas ou a fazer exames 0,466 0,683 25 É difícil definir, na prática, o papel e as responsabilidades de cada profissional da ESF 0,538 0,626 5 Os profissionais prescrevem medicamentos que o usuário não terá dinheiro para comprar 0,468 0,563 0,382 Fator 3. Participação dos autores Prática das equipes (α=0,76) 23 Existe falta de respeito entre os membros da equipe da ESF 0,390 0,768 22 As equipes de saúde da família não colaboram umas com as outras 0,563 0,324 0,678 24 Os profissionais da equipe não apresentam perfil para trabalhar na ESF 0,632 0,349 0,626 21 Os profissionais das equipes de ESF atuam com falta de compromisso e envolvimento 0,394 0,539 Fator 4. Perfil profissional (α=0,72) 4 Os profissionais fazem prescrições inadequadas ou erradas 0,366 0,778 2 A equipe da ESF prejulga os usuários e familiares com base em preconceitos e estigmas 0,214 0,694 3 O profissional trata o usuário com falta de respeito 0,281 0,412 0,668 Fator 5. Privacidade (α=0,70) 12 O ACS conta a seus vizinhos informações obtidas no seu trabalho a respeito de usuários e famílias 0,415 0,826 10 O ACS comenta informações sobre a intimidade da família e do casal com a equipe de saúde 0,307 0,324 0,764 13 O profissional conta informações sobre a saúde de um dos membros da família que ele atende para os demais membros dessa família 0,370 0,593 Fator 6. Sigilo (α=0,64) 27 Usuários pedem a um dos membros da equipe de saúde da família que os outros membros não tenham acesso a alguma informação relacionada à sua saúde 0,333 0,834 30 Usuários pedem a um dos membros da equipe de saúde da família que os outros membros não tenham acesso a alguma informação relacionada à sua saúde, mesmo em situação em que seja necessária a participação da família no cuidado 0,404 0,601 20 O profissional conta informações sobre a saúde de um dos membros da família que ele atende para os demais membros dessa família, quando este não consegue gerenciar o autocuidado e se expõe a riscos 0,434 0,322 0,581 16 Menores de idade procuram a UBS e pedem à equipe exames, medicamentos ou outros procedimentos sem autorização e/ou conhecimento dos pais 0,374 0,354 0,319 0,528 Alpha 0,85 0,70 0,76 0,72 0,70 0,64 % variância 16,02 9,75 9,72 9,03 8,67 8,20 % cumulativa 16,02 25,77 35,50 44,54 53,21 61,42 Artigos de pesquisa Artigos de pesquisa http://dx.doi.org/10.1590/1983-80422014222012 http://dx.doi.org/10.1590/1983-80422014222012 Rev. bioét. (Impr.). 2014; 22 (2): 309-17 317
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Supplementary Methods and Materials, Figures 1-6 from Use of a Cryptic Splice Site for the Expression of Huntingtin Interacting Protein 1 in Select Normal and Neoplastic Tissues
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Supplemental Materials and Methods Survival analysis in TRAMP mice. The Hip1null/null and Hip1Δ3-5/Δ3-5 mice were maintained on a mixed C57BL/6;129svJ background, and the TRAMP mice were maintained on a pure C57BL/6 background. Intercross matings of TRAMP and Hip1null/null and Hip1Δ3-5/Δ3-5 mice were performed as previously described (1). Fourteen TRAMP;Hip1Δ3-5/Δ3-5, 13 TRAMP;Hip1+/Δ3-5, 18 TRAMP;Hip1+/null, and 15 TRAMP/Hip1null/null littermates were analyzed for tumors at 6.5 months. Prior to these necropsies, a group of mice from these cohorts either unexpectedly died or became moribund and required euthanasia. This survival data for each of these observation groups was compared. RNA isolation and northern blot. Total RNA was isolated from cultured tumor cells, tissues, and early passage mouse embryonic fibroblast (MEF) extracts using the TRIzol reagent (Invitrogen). Poly (A) RNA was isolated from total RNA using the Poly(A) Purist MAG protocol (Ambion). Then, 5ug of this poly(A) RNA was separated on a 1% agarose gel with 6% formaldehyde, stained with ethidium bromide, transferred to Nytran membrane (Schleicher & Schuell), and cross-linked. The membrane was prehybridized in a buffer containing 5X SSC, 5X Denhardt solution, 1% sodium dodecyl sulfate (SDS) (wt/vol), and 100 μg of denatured salmon sperm DNA/ml for 3 h at 65°C. For the mouse Hip1 Northern probe, an 850-bp EcoR1 and Not1 digested fragment encoded by mHip1 exons 10-14 was used. The probe was 32P labeled using a random-primed labeling kit according to manufacturer’s directions (Roche). The blot was hybridized overnight at 65°C, washed twice in 2X SSC for 20 min, once in 1X SSC for 10 min, and twice in 0.1X SSC for 10 min. The blot was exposed for 4 to 5 days on Kodak Biomax film. The mRNA abundance was normalized with the signal for glyceraldehydes-3-phosphate dehydrogenase (GAPDH). Tissue preparation and western blot analysis. Tissue harvesting, preparation, and immunoblotting of tissues was performed as previously described (2). A polyclonal antiHIP1 (1:5,000, UM354) antibody was used to detect HIP1 expression in MMTV-myc, TRAMP and Mx1-Cre mice, and polyclonal anti-actin (1:1000, Sigma) antibody was used as a control. Co-immunoprecipitation of HIP1 and EGFR and endocytic factors. Full-length and mutant EGFR and HIP1 cDNA constructs in pcDNA3 have previously been described (3). A 15-cm dish of 70% confluent 293T cells was transfected with 20 μg of HIP1 cDNA and 20 μg of EGFR cDNA using Superfect reagent (Qiagen). Twenty-four hours post-transfection, the cells were lysed using an all-purpose lysis buffer [50 mmol/L Tris (pH7.4), 150 mmol/L NaCl, 1% Triton X-100, 1.5 mmol/L MgCl2, 5 mmol/LEGTA, 10% glycerol, Complete EDTA-free protease inhibitor tablets (Roche), 30 mmol/L sodium pyrophosphate, 50 mmol/L sodium fluoride, and 100μmol/L sodium orthovanadate]. Five milligrams of protein were incubated with pre-immune serum, polyclonal anti-HIP1 serum (UM323), or sheep polyclonal anti-EGFR (Upstate). One hundred microliters of a 3:1 slurry of protein G-sepharose beads (GE Healthcare) in lysis buffer were then incubated with the lysate-antibody mixture at 4ºC for 60 min with rotation. The protein G pellets were washed four times with 1 mL of lysis buffer. The entire pellet was dissolved in SDS sample buffer, boiled for 5 min, separated on 7% SDSPAGE, and transferred to nitrocellulose membranes. Antibodies used for western blot analysis were the anti-HIP1/4B10 antibody (mouse monoclonal, human anti-HIP1 immunoglobulin G1, 400 ng/mL), anti-adaptin-α antibody (rabbit polyclonal, BD Biosciences), anti-clathrin heavy chain TD-1 antibody (kind gift of Linton Traub, University of Pittsburgh), and an anti-EGFR antibody (sheep polyclonal antibody, Upstate Biotechnology, Charlottesville, VA). percent tumor-free 100% Myc+;Hip1 null/null (N=6) Myc+;Hip1 +/null (N=16) 80% Myc+;Hip1 Δ3-5/d3-5 (N=17) 60% Myc+;Hip1 +/Δ3-5 (N=38) 40% 20% 0% 20 30 40 50 weeks of age Supplemental Figure 1. Tumorigenesis in MMTV-myc mice in the absence of HIP1. Percent tumor-free survival out to 50 weeks of age is shown for MMTVMyc+ mice on various HIP1 knockout backgrounds. Mice were sacrificed when the tumor ulcerated or impeded movement. TRAMP 0.80 MMTV-Myc mice 6/11 19/37 3/4 0.60 0.40 nu ll nu ll / nu ll H ip 1+ / nu l l/ nu ll 0.20 Supplemental Figure 2. Tumor incidence in mice with Hip1D3-5 and Hip1Null alleles. MMTV-myc transgenic and TRAMP mice were mated with mated on to HIP1null/null and HIP1Δ3-5/Δ3-5 backgrounds and analyzed for tumor incidence. TRAMP mice that survived to 6 months of age were scored for gross prostate tumors. In each case the mice with the D3-5 allele were afflicted with more tumors. A. A. Survival curve TRAMP/dKIHIP1 & TRAMP/d3-5 Percent of Mice (%) 100 80 + null (n=18) 60 null null (n=15) 40 +/Δ3-5 (n=13) Δ3-5/Δ3-5 (n=14) 20 0 1 2 3 4 6 7 Months B. bladder Seminal vesicle Supplemental Figure 3. A. Survival curve of TRAMP mice in different Hip1 mutant backgrounds. B. Example of bilateral synchronous prostate tumors. Arrows indicate tumors arising from distinct lobes of the prostate (not visible). Mouse Hip1 cDNA exon2/exon3 junction exon 2 exon 2 Hip1Δ3-5 cDNA exon 3 ···························· CGTGTATTCTGGGCACCCACCATGAGAAAGGAGCGCAGACC exon 6 GTGGCCGTGAAAGAGAAACATGCCAGGA ag AATCCCAGGTTCCCGGGCAACCTCCAGATGAGTGACCGA exon 5 exon 6 Mouse Hip1 cDNA exon5/exon6 junction CTGAGAACAAGGATGGAGTACCACACCAAA ······································· Supplemental Figure 4. Partial Hip1Δ3-5 cDNA sequence alignment with wild type mouse Hip1 cDNA. Shown is an alignment of cDNA sequence from the nested PCR reaction with the exon 2/3 and exon 5/6 junctions of mouse Hip1 mRNA reference sequence (NM_146001). Dots in the moue Hip1 mRNA reference sequence denote identity with the Hip1 D3-5 cDNA sequence. Codons are represented by alternating bold/nonbold trinucleotide sequences. Note the AG dinucleotide insertion between exons 2 and 6 of the Hip1D3-5 cDNA sequence, which maintains the open reading frame of the transcript. e17.0 MEFs +/+ +/ Δ3-5 Δ3-5/ Δ3-5 +/+ e17.0 brain +/ Δ3-5 Δ3-5/ Δ3-5 120kD Lane 1 2 3 4 5 6 7 8 9 10 11 12 Supplemental Figure 5. HIP1Δ3-5/insAG 106 kDa protein is present in mouse embryonic brain and fibroblasts. Western blot analysis for HIP1 expression in the brains (left panel) and fibroblasts (right panel) of 17-day old mouse embryos of different genotypes demonstrated the presence of a slightly truncated HIP1 product. MEF cells of different genotypes were cultured from eleven individual embryos from the same mother. Only 5 samples are shown here but all demonstrated similar banding patterns as related to the distinct genotypes. LPA S1P LPC PI(3,4)P2 PI PI(3,5)P2 PI(3)P PI(4,5)P2 PI(4)P PI(3,4,5)P3 PI(5)P PA PE PS PC Blank GST-HIP1/WT GST-HIP1/Δ3-5 Supplemental Figure 6. Comparison of lipid binding specificity and relative affinity GST-5’HIP1/Δ3-5 and GST-5’HIP1 using PIP strips. Protein solutions containing 10µg of either purified GST-5’HIP1 or GST-5’HIP1/Δ3-5 protein in TBST with 1% milk were incubated with PIP strips (Echelon) containing 15 different lipids at 100 pmol/spot. Lipid-protein interactions were detected using a polyclonal antibody (UM354) that recognizes both GST-5’HIP1 and GST5’HIP1/Δ3-5 proteins. Both proteins bound preferentially to PI(3)P on the PIP strips. Supplemental Data References 1. Bradley SV, Oravecz-Wilson KI, Bougeard G, et al. Serum antibodies to huntingtin interacting protein-1: a new blood test for prostate cancer. Cancer Res 2005;65(10):4126-33. 2. Hyun TS, Li L, Oravecz-Wilson KI, et al. Hip1-related mutant mice grow and develop normally but have accelerated spinal abnormalities and dwarfism in the absence of HIP1. Mol Cell Biol 2004;24(10):4329-40. 3. Bradley SV, Holland EC, Liu GY, Thomas D, Hyun TS, Ross TS. Huntingtin interacting protein 1 is a novel brain tumor marker that associates with epidermal growth factor receptor. Cancer Res 2007;67(8):3609-15.
https://openalex.org/W2875135162
https://digitalcommons.wustl.edu/cgi/viewcontent.cgi?article=10899&context=open_access_pubs
English
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A systematic digital approach to implementation and dissemination of eating disorders interventions to large populations identified through online screening: implications for post-traumatic stress
mHealth
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public-domain
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A systematic digital approach to implementation and A systematic digital approach to implementation and dissemination of eating disorders interventions to large dissemination of eating disorders interventions to large populations identified through online screening: Implications for populations identified through online screening: Implications for post-traumatic stress post-traumatic stress C. Barr Taylor Palo Alto Univesity Josef I. Ruzek Stanford University Ellen E. Fitzsimmons-Craft Washington University School of Medicine in St. Louis Andrea K. Graham Northwestern University Katherine N. Balantekin State University of New York at Buffalo Follow this and additional works at: https://digitalcommons.wustl.edu/open_access_pubs Please let us know how this document benefits you. A systematic digital approach to implementation and dissemination of eating disorders interventions to large populations identified through online screening: implications for post-traumatic stress C. Barr Taylor 1,2, Josef I. Ruzek 1,2,3, Ellen E. Fitzsimmons-Craft 4, Andrea K. G Balantekin 6 I. Ruzek 1,2,3, Ellen E. Fitzsimmons-Craft 4, Andrea K. Graham 5, Katherine N. C. Barr Taylor 1,2, Josef I. Ruzek 1,2,3, Ellen E. Fitzsimmons-Craft 4, Andrea K. Graham 5, Katherine N. Balantekin 6 1Center for m 2 Health, Palo Alto University, Palo Alto, CA, USA; 2Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA, USA; 3National Center for PTSD, Dissemination and Training Division, Veterans Affairs Palo Alto Health Care System (VAPAHCS), Menlo Park, USA; 4Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA; 5Department of Medical Social Sciences, Northwestern University, IL, USA; 6Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, USA Contributions: (I) Conception and design: All authors; (II) Administrative support: None; (III) Provision of study materials or patients: EE Fitzsimmons-Craft KN Balantekin; (IV) Collection and assembly of data: None; (V) Data analysis and interpretation: None; (VI) Manuscript 1Center for m 2 Health, Palo Alto University, Palo Alto, CA, USA; 2Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA, USA; 3National Center for PTSD, Dissemination and Training Division, Veterans Affairs Palo Alto Health Care System (VAPAHCS), Menlo Park, USA; 4Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA; 5Department of Medical Social Sciences, Northwestern University, IL, USA; 6Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, USA Contributions: (I) Conception and design: All authors; (II) Administrative support: None; (III) Provision of study materials or patients: EE Fitzsimmons-Craft, KN Balantekin; (IV) Collection and assembly of data: None; (V) Data analysis and interpretation: None; (VI) Manuscript writing: All Authors; (VII) Final approval of manuscript: All authors. Correspondence to: Dr. C. Barr Taylor, MD. Center for m 2 Health, Palo Alto University, 1791 Arastradero Rd, Palo Alto, CA 94304, USA. Email: btaylor@stanford.edu. Background: We describe an approach to implementation and dissemination that focuses on changing outcomes variables within a large, defined population and attempts to provide cost-effective opportunities and resources—which might include the provision of both digital and traditional interventions—to address individual needs and interests. We present a case example of how aspects of this model are being applied to increase reach, engagement and outcomes for individuals who complete a national eating disorders screen, and are likely to have an eating disorder but who are not in treatment. Recommended Citation Recommended Citation Taylor, C. Barr; Ruzek, Josef I.; Fitzsimmons-Craft, Ellen E.; Graham, Andrea K.; and Balantekin, Katherine N., "A systematic digital approach to implementation and dissemination of eating disorders interventions to large populations identified through online screening: Implications for post-traumatic stress." Mhealth. 4, 25 (2018). https://digitalcommons.wustl.edu/open_access_pubs/9907 This Open Access Publication is brought to you for free and open access by Digital Commons@Becker. It has been accepted for inclusion in Open Access Publications by an authorized administrator of Digital Commons@Becker. For more information, please contact vanam@wustl.edu. Original Article Page 1 of 13 © mHealth. All rights reserved. Introduction As will be described in this paper, the “systematic approach” refers to frequent review of the success of the program in achieving the desired aims and iterating new strategies, as needed, to improve outcomes. We assume that population monitoring and many interventions provided to individuals will be digital, although not exclusively so. We focus on a defined eating disorder population identified through online screening. Many individuals with post- traumatic stress (PTS) are likewise identified through screening. In the following we: (I) discuss how aspects of this model have been applied to one defined population— individuals with eating disorders identified by a nationally disseminated screen, (II) explain how the model could be applied to PTS populations, and (III) conclude with a discussion of strengths and limitations of the model. In this paper, we describe an approach to implementation and dissemination that focuses on changing outcomes variables within a large, defined population and attempts to provide cost-effective opportunities and resources—which might include the provision of both digital and traditional interventions—to address individual needs and interests. In this model, teams within organizations invested in improving outcomes use moderator, process, and outcome data to improve quality of care. The model differs from traditional implementation and dissemination models in focusing on a range of potential options and changes for the whole defined population, rather than ensuring that a single effective intervention for a given subset of the population is provided consistent with best practices, and in using intervention outcomes and monitoring teams tasked with helping to ensure the best outcomes for the population. Such teams are now commonplace in most commercial enterprises to increase customer satisfaction and sales. The approach is designed to be dynamic and iterative in the sense that the prevention and intervention system and opportunities are continuously revised to increase reach, engagement, effectiveness, and personalization of interventions. Such models also lend themselves to modern analytic and intervention design methods. We refer to this as a systematic digital approach to defined population-based interventions. A systematic digital approach to implementation and dissemination of eating disorders interventions to large populations identified through online screening: implications for post-traumatic stress We then describe how this model can apply to post-traumatic stress (PTS) and conclude with a discussion of limitations and issues with the model. Methods: The National Eating Disorders Association (NEDA) provides online screening for eating disorders. Results: From February 2017 through March 2018, over 200,000 individuals completed the NEDA screen. Of these, 96% screened positive or at risk for an eating disorder, and most of those who screened positive for a clinical/subclinical eating disorder were not currently in treatment. Less than 10% engaged in self-help or guided self-help online digital program, or expressed interest in calling a helpline for referral to treatment. Results: From February 2017 through March 2018, over 200,000 individuals completed the NEDA screen. Of these, 96% screened positive or at risk for an eating disorder, and most of those who screened positive for a clinical/subclinical eating disorder were not currently in treatment. Less than 10% engaged in self-help or guided self-help online digital program, or expressed interest in calling a helpline for referral to treatment. Conclusions: A systematic digital approach to implementation and dissemination has the potential to increase the number of individuals who benefit from interventions in defined populations. Uptake rates need Conclusions: A systematic digital approach to implementation and dissemination has the potential to increase the number of individuals who benefit from interventions in defined populations. Uptake rates need to be improved. Keywords: Implementation; dissemination; digital mental health; eating disorders; post-traumatic stress (PTS); post-traumatic stress disorder (PTSD) Received: 09 March 2018; Accepted: 29 May 2018; Published: 10 July 2018. doi: 10.21037/mhealth.2018.05.06 View this article at: http://dx.doi.org/10.21037/mhealth.2018.05.06 Received: 09 March 2018; Accepted: 29 May 2018; Published: 10 July 2018. doi: 10.21037/mhealth.2018.05.06 View this article at: http://dx.doi.org/10.21037/mhealth.2018.05.06 mHealth 2018;4:25 © mHealth. All rights reserved. mhealth.amegroups.com mHealth, 2018 Page 2 of 13 enrolled groups. Case example: providing better access to effective treatments for eating disorders identified through a national screen Eating disorders are common and disabling problems, negatively impacting quality of life. Eating disorders affect an estimated 3.5–6.5% and 3–3.5% of women and men, respectively, in the Western world (1,2). Eating disorders are associated with high medical and psychiatric comorbidity and increased mortality with anorexia nervosa having the highest mortality rate of all mental disorders (3). Like post-traumatic stress disorder (PTSD), eating disorders are comorbid with several other problems, and follow a chronic course. Furthermore, risk factors for eating disorders have been identified and shown to be modifiable, with reduction in risk factors associated with reduced eating disorder onset (4,5). Also, like PTSD, effective treatments are available but reach only a small percentage of the affected population. Indeed, less than 20% of individuals with eating disorders report receiving treatment (6). As such, systematic approaches to preventing and treating eating disorders have relevance to those experiencing PTS symptoms and preventing and treating PTSD. © mHealth. All rights reserved. mhealth.amegroups.com mHealth 2018;4:25 A systematic digital approach to defined population-based interventions A ‘defined population’ refers to any population with shared characteristics, such as gender, disease, geography, or combinations of such factors. In public health, “defined populations” have outcome targets, such as increasing the number of individuals who are vaccinated, who have reduced cardiovascular risk factors, or who no longer meet criteria for being a “case” and/or a combination of these. A defined population model does not mean that all individuals within the population are provided the same intervention. In fact, it is assumed that there will be multiple pathways for different individuals and subpopulations, depending on their level of need and interest. ‘Defined population’ targets are particularly useful when they map onto organizations or systems responsible for, or invested in, achieving the desired outcomes, such as a public health department or programs that cover medical coverage for Over the past 10 years, we have been involved in a number of studies to integrate preventive and treatment approaches to populations with high rates of eating disorders (7). The following section describes a case example of applying a digitally-based systematic approach to disseminating and implementing interventions for eating disorders identified through screening. The approach is digital in the sense that the screening and feedback are mhealth.amegroups.com mHealth 2018;4:25 mHealth, 2018 Page 3 of 13 Screen Low risk for eating disorders: screen negative for eating disorders or elevated risk status Offered online, universal health education intervention High risk for eating disorders: screen negative for ED; screen positive for elevated risk (e.g., weight/shape concerns) Offered online, targeted ED prevention intervention Clinical/subclinical eating disorder other than Anorexia Nervosa (AN): screen negative for AN; screen positive for any other ED Not in treatment but interested in treatment*: referral, alerted to self-help, online treatment options Anorexia Nervosa: screen positive for AN Referral for clinical evaluation and treatment Figure 1 NEDA Screen algorithm and general referral issues. *, population of interest. NEDA, National Eating Disorders Association. Figure 1 NEDA Screen algorithm and general referral issues. *, population of interest. NEDA, National E hm and general referral issues. *, population of interest. NEDA, National Eating Disorders Association. individuals can click on a link without beginning it, we define uptake as using >1 session. In this model, targets are established for each phase of identification and screening. A systematic digital approach to defined population-based interventions The targets are arbitrary and should change as the population recruited changes, rates of uptake, engagement and outcome are determined and new interventions/ opportunities added. In theory, everyone who screens positive for an eating disorder and is interested in treatment should begin an intervention. In reality, the available treatment options, cost and other factors make it unlikely that most would do so. In a recent study, about 50% of students who screened positive for an eating disorder clicked on an on-line program (the only option available) (9). Engagement can be defined in various ways, but the most common one, and one we use, is the number of sessions completed. However, as discussed below, early engagement is probably more important than later engagement, and our primary metric is the number of individuals who begin a program (>1 session) and go on to complete 50% of sessions. This is also arbitrary, but for an on-line program, it indicates that students have at least opened the program and moved to the second session. A UK study found that about 50% of individuals referred to face-to-face treatment never initiate treatment (11) so that 50% reach/engaged would seem to be a reasonable target rate for both online and face-to-face interventions. The outcomes we focus on are a significant reduction of symptoms (>50% reduction from baseline) and/or no longer meet case criteria. These criteria provided in a digital format and data monitoring is digital as are many of the interventions. This approach builds on a program of research in which we have helped identify risk factors for eating disorders (8), developed and examined interventions to reduce eating disorders, and shown that reduction in eating disorder risk reduces disease onset (4,5). We have also developed an evidence-based screen that can sort users into categories of no risk, low risk, or high risk for an eating disorder, or eating disorder diagnosis groups [i.e., the Stanford-Washington University Eating Disorders Screen (SWED)] (9). These groups can then be linked to relevant interventions for an estimated cost-benefit analysis of this model (10). Our general model for screening and delivering interventions can be seen in Figure 1. One advantage of a population-based approach is that both populations at risk for, or with clinical symptoms, can be identified simultaneously and prevention and intervention programs can be provided as appropriate (7). However, in this paper we only focused on those with clinical symptoms. © mHealth. All rights reserved. mHealth 2018;4:25 Page 4 of 13 Table 1 Potential interventions for the defined population Intervention Provider Access Effects Cost to user Digital component Issues Self-help Commercial, bibliotherapy, various High Low Low App Unknown impact on subsequent use Guided self-help Commercial High Medium Low- moderate App Few individuals want to pay for on-line programs Teletherapy or blended Individuals Low High Low (if insured); high if not Teletherapy online program; app; text; Email Practice issues; access; training Face-to-face, including group Individuals Low High Low (if insured); high if not None Access; training Table 1 Potential interventions for the defined population Table 1 lists potential interventions offered for individuals within the defined population. As noted by Munoz (13), interventions can be characterized as (I) self-help (digital/ bibliotherapy), (II) coached/guided, (III) teletherapy, (IV) blended therapy (digital/text/e-mail and face-to-face) and V) pure face-to-face (Table 1). are based, in part, of those developed for the VA training program in evidence-based interventions for depression (12) and the effect sizes of the online and face-to-face interventions. Our long-term goal is a significant reduction in the prevalence of eating disorders in this population that would occur through a combination of prevention (not discussed in this paper) and intervention (10). One of the advantages of the model is that it identifies upstream issues (non-acceptance of referrals, for instance, or not showing up) that need to be addressed to provide a significant benefit for the defined population of interest. Screening In this model, individuals with a potential eating disorder are identified with an evidence-based screen, the SWED (Stanford Washington University Eating Disorder Screen). The screen has been shown to have acceptable sensitivity and specificity (9). Starting in 2016, our research teams based at Stanford University, Palo Alto University, and Washington University in St. Louis partnered with the National Eating Disorders Association (NEDA) to make the SWED screen freely available on their websites in 2017. Individuals are made aware of the screen via NEDA through a variety of social media sites and activities and a weeklong campaign (NEDA awareness week) many US colleges and universities. The screen partitions individuals into no or low risk, high risk of ED onset, or possible ED as per Wilfley et al. (7). (The actual screen can be found at: www.nationaleatingdisorders.org.) © mHealth. All rights reserved. Self-help Pure self-help programs have the advantage of being inexpensive and readily available as books and online but are associated with high dropout rates and low to moderate effect sizes (14). Little is known about how one might best benefit from a self-help program, if there are downsides, and the possible consequences of failure to improve following self-help and effects on subsequent uptake of more intensive forms of assistance (face-to-face therapy). For instance, individuals who fail to improve with self-help may be reluctant to proceed with more intensive approaches and/or feel like ‘treatment failures’. Likewise, little is known about moderators and mediators that predict better outcomes. Such issues illustrate the potential benefit of a systems model of defined population-level interventions. Moderator and mediator analyses tied to engagement and dropout levels of individuals choosing self-help could be used to identify those who might most benefit from this type of intervention and suggest subpopulations where further trialing could help improve outcomes. The work is ongoing and we discuss how we have been trying to address providing evidence-based treatment to the individuals identified through a national screening effort. A systematic digital approach to defined population-based interventions For the purposes of the following discussion, the defined population represents all individuals who completed a national screen who are found to screen positive for an eating disorder but are not currently in treatment (see asterisk for in Figure 1). Defined population reach is the number of these individuals who complete the screen and begin a program of their choosing (i.e., uptake into an intervention). For purpose of clarity, we will use the term ‘reach/uptake’ rather than merely reach and, since mhealth.amegroups.com mhealth.amegroups.com mHealth 2018;4:25 mHealth, 2018 Page 4 of 13 mHealth 2018;4:25 Teletherapy Teletherapy, as used here, is the provision of psychological services via digital means, including the telephone, text messaging, video or combinations therefore. To reach our widespread population, teletherapy would seem to be a reasonable approach. Teletherapy is often limited by practice guidelines (e.g., therapists restricted from practicing across state lines). In the VA, teletherapy has demonstrated initial efficacy and feasibility (17). In theory, users interested in teletherapy could be given names of providers vetted through some type of quality assurance/best practice model. Teletherapy might be particularly useful when some type of specialized intervention is necessary, such as expertise in dealing with issues relevant to a subgroup, language, disability or diagnosis. © mHealth. All rights reserved. Discussion The first year of our joint efforts working with NEDA suggest that efforts to reach a large number of individuals with eating disorders who are not currently in treatment has been very successful. However, the preliminary data also suggest that few individuals who might benefit from treatment engage in even minimal interventions, such as clicking to learn more about a self-help program [although because of the large reach, large numbers of individuals (i.e., over 10,000) have done so]. In the next phase of our partnership, we are considering evaluating ways to increase reach as seen in line two of Table 2. This is not an exhaustive list. Other analyses will compare (e.g., using ROC analyses) those who choose the various options based on baseline demographics, diagnoses, geographic region, and other variables to help us gain a better understanding of what alterations need to be considered that might improve engagement. Of particular importance, the program does not provide post recommendation motivational interviewing, program selling (e.g., testimonials, promotions), or other interventions that might increase uptake. A broader range of interventions also needs to be considered. If even the low cost of the Lantern program proves to be an obstacle, would free, semi-automated programs increase uptake? While such programs may have smaller effect sizes than guided self- help programs guided by a human coach, if more individuals use them, they may have great value when considering their effects on a population. Since thousands of screens are completed each month, it will be possible to conduct a series of mini-experiments to examine options that might increase uptake such as using machine learning to determine how the helpline can be more effective in motivating individuals to seek online therapy who have access and resources to do so. Other options included blended therapy, face-to-face therapy and stepped care models. Of the options, NEDA currently offers the following for individuals who screen positive for a possible eating disorder: (I) self-help via Recovery Record (18), (II) commercially available guided self-help (www.golantern. com), (III) access via a helpline to a treatment provider database to find a referral to a therapist trained in evidence based practice, and/or (IV) access to a chatline. Respondents are also encouraged to review the information and resources provided on the NEDA website. Guided online interventions Guided online self-help interventions are associated with success rates that are higher than unguided programs and comparable to face-to-face interventions for many mental health disorders (15) including eating disorders (16). Guided mhealth.amegroups.com mHealth 2018;4:25 Page 5 of 13 mHealth, 2018 online self-help programs for eating disorders are available through commercial companies at a cost of about $50/month per user. proportion of those who clicked on one of the options who actually meaningfully engaged with the option (e.g., self-help or guided self-help program) or who engaged in in-person treatment as a result of accessing the helpline or chatline. From other sources we can estimate, that for all interventions the numbers would all be below 50%. mHealth 2018;4:25 mhealth.amegroups.com Results Unfortunately, data are not yet available on the mhealth.amegroups.com mhealth.amegroups.com mHealth 2018;4:25 mHealth, 2018 Page 6 of 13 Page 6 of 13 Table 2 Key variables for a systematic approach to implementation and dissemination Component Example of methods Reach (those who might have an eating disorder) Social media Health care providers Local community/site activities led by volunteers Reach & uptake Improve readability/language of screen and feedback to make it very user friendly Provide motivational interviewing Introduce testimonials Increase access to screen, including to underrepresented groups Expand treatment choices available to the population Increase self-help options Link to practitioners of teletherapy (increase access to evidence-based practice) Add Spanish language versions Add male version Add version to address overweight or obesity, for a subset for whom weight loss is appropriate Improve engagement (for those using online programs) Use A/B and other digital design methods to evaluate program feature options Monitor user satisfaction with components Develop programs appealing to subpopulations Personalize Expand training to providers Provide training in blended therapy Provide training in evidence-based practice Reduce cost Automate interventions Provide self-help Make interventions more effective Make training in evidence-based practice available online Increase efficacy Match user to most effective program Add programs shown to be effective to treatment options menu Table 2 Key variables for a systematic approach to implementation and dissemination Of note, the system we propose should continuously try to improve reach/engagement and outcomes towards the targets of the organization with cost-effectiveness. self-help programs have been found to have low to medium effect sizes, guided self-help programs moderate to large effect sizes. However, it is important to determine if these effects are maintained when programs are offered to larger populations and NEDA is now collecting program use data from their two main digital referral resources (i.e., Recovery Record, GoLantern). It will also be important to consider other options, such as incorporating face-to-face groups alone or in combination with consumer-led and/or moderated on- line groups. On-going data monitoring should also help us to determine the relative cost/benefit and even harm of the different approaches and to help inform recommendations. © mHealth. All rights reserved. Results From about February 2017 to April 2018, the screen has been completed by over 200,000 individuals. The majority of those completing the screen were classified as being at high risk for eating disorders (ED) onset or having a clinical/subclinical eating disorder (96%). Further, the majority (86%) of individuals screening positive for a clinical/subclinical eating disorder were not currently in treatment. Screens were completed from individuals in most counties of the US and in many places unlikely to have practitioners with training in eating disorder treatment. In parallel studies we have been examining ways to improve engagement in individuals using the new online program. Followed a series of changes based on user feedback and analyses we increased early engagement from 69.5% (n=105/151) to 78.7% (n=70/89). As with engagement, outcome data can be examined in more conventional trials. For eating disorders, as discussed above, Uptake has varied relative to the population screen and the options available, but overall, less than 10% of individuals clicked on one of the options. Of these about 2/3s clicked on the self-help option and about 12% on the guided self-help program. Support accessible database and the partners have expertise in big data analysis and intervention design. The biggest weakness is that the project’s success depends on the goodwill and working relationships of the partners since it is minimally funded. Furthermore, users need to volunteer to share their data. The model uses baseline, process and outcome data to improve reach, engagement and outcome. While data on users’ intentions to act on referrals is collected, except for the small subsample willing to provide contact information for follow-up, we can only estimate from other programs we provide if respondents began the program, how much of it they used and what the outcomes were. Another option is to partner with companies that select therapists based on their evidence-based training and requires therapists in the network to provide periodic progress data on clients. Another limitation of the defined population model is having a group or organization with adequate resources committed to achieving the population level outcomes. For lack of a better term, we call this the “Outcomes Optimization Team”—those who manage the components of the digital interventions to achieve better outcomes in this population. In our case, it is comprised of the participating teams from Washington University, Palo Alto University, University of Buffalo and NEDA in association with their partners who provide specific expertise. For PTS, it could be national organizations, including health care systems or emergency response agencies. to a broader approach that combines universal, targeted/ selected prevention and intervention, as illustrated in Figure 1. A strategy that combines both prevention and intervention is most likely to achieve reduction of prevalence of a disorder in a population, which is the most difficult, but perhaps the most important outcome for a population (10). Social media could also be leveraged effectively in this model for such things as increasing the reach of the screen, providing education around relative issues, encouraging activism around important issues, and creating supportive networks. Application to PTS The population-based strategy described above for treating eating disorders could be applied to assisting those experiencing problems related to trauma exposure and PTS. An advantage of the strategy is its operational definition of the population in terms of individuals who have completed a screening process, and this same approach might usefully be extended to PTS initiatives. Many existing traumatic stress response systems invoke implicit systems models applied to populations. The Veterans Health Administration (VHA) focuses much of its mental health resources on Veterans exposed to combat and other war-related stressors, and brief screening for PTSD is a standard practice in primary care settings and elsewhere in VA and the Department of Defense. Disaster mental health responses typically focus on large groups of survivors of a specific traumatic event (e.g., 9/11 attacks, Hurricane Katrina), and screening processes taking place online or in crisis counseling settings could be used to identify populations of interest. Below, we discuss © mHealth. All rights reserved. Critical components to the model To the extent this systematic defined population model proves viable, it is worth considering the components of the delivery system that might have led to our success thus far (Table 3). First, the partnering team is diverse and has expertise in areas critical to the design and refinement of interventions. Second, the model is supported by a large, mHealth 2018;4:25 mHealth 2018;4:25 mhealth.amegroups.com Page 7 of 13 mHealth, 2018 Table 3 Critical components of a systematic digital approach to implementation and dissemination Component Characteristics Defined population Individuals who share common characteristics Outcome managers (those responsible for looking after the defined population) Individual, groups, institutions responsible for monitoring achievement of outcomes Database Reach, engagement, outcome monitoring Data analytic team Members responsible for monitoring the outcome/progress Outcomes optimization team Individuals responsible for providing interventions relevant to the population and to individuals within the population Support Financial support, administrative leadership buy-in Checks and balances Consumer, affected members input, privacy Delivery systems Software, practitioners, coaches, etc. mHealth 2018;4:25 Systematic interventions for individuals with PTS within a health care system In this example, the focus would be on individuals with PTS served by a health maintenance organization (HMO), characterized as a health system with a defined network of providers and services. The defined population would be identified by a trauma screen, such as the PC-PTSD (19), made available to members of a health care system through screening at health care appointments, provider websites, and even notifications to members. As with the eating disorder case example, the defined population would be those people screening positive for PTS. Reach would be defined as the number of eligible members who engage in the intervention, and the outcome measures related to effectiveness would focus on reduction in PTS symptoms 6 months post screening. For an HMO population, a team would need to be responsible for enacting and monitoring the interventions. Data analytic, intervention(s) monitoring, outcomes, and training teams would need to be established, and first line interventions would need to be chosen based on evidence, institutional resources, and other factors (e.g., patient preferences). As with eating disorders, stages of implementation might occur sequentially. Initial implementation might include delivery of a specific combination of screening, unguided self-help, guided self-help, teletherapy/blended therapy, or face-to-face treatment. The set of interventions considered for implementation and study would be like those for eating disorders: self-help, guided/coached self-help, teletherapy, blended therapy, and face-to-face. Initial intervention selections would likely include self-help, guided self-help, teletherapy, and face-to- face interventions. Many websites provide trauma survivors with information and self-care recommendations, and there are a number of self-help manuals available. Increasingly, phone apps and internet interventions designed for self- management are being made available. For example, the national center for PTS within the US Department of Veterans Affairs has developed a range of smartphone apps (e.g., PTSD Coach, PTSD Family Coach, PE Coach) designed to assist Veterans (and others) with PTSD. Guided, coached interventions are also available for PTS and have been shown to be effective (20,21). Research supports comparability of face-to-face and teletherapy- delivered treatments provided to PTS populations (17) and teletherapy has been widely implemented for PTSD in VA. By contrast, blended therapies have as yet seen little application and their widespread implementation, at least initially, would be challenging. Page 8 of 13 based interventions have been developed and specified in clinical practice guidelines, they are not routinely available and most practitioners have not been trained in these interventions. Costs may limit their accessibility for low- income groups. The treatments themselves often require around 12 weeks to deliver, and may be inconvenient or unpersuasive for some users. These treatments are typically individualized and therefore cannot be delivered more cost-effectively to larger groups. Many of those with problems are unwilling to seek care due to stigma and other factors, and once initiated, dropout rates from face-to-face treatment are high. how a screen-based defined population approach could be directed to individuals with PTS enrolled in a health care system. Similar methods could be used with other traumatized populations, such as those affected by a disaster within a defined geographic area. © mHealth. All rights reserved. Universal, targeted/selected prevention and intervention Although we have focused on the systematic digital approach as applied to clinical cases, the model lends itself mhealth.amegroups.com mHealth 2018;4:25 mhealth.amegroups.com mHealth, 2018 Page 8 of 13 Benefits, challenges, and key questions for a systematic digital defined population approach The systematic digital approach has the potential benefit of increasing the provision of accessible, affordable, and evidence-based intervention resources to populations in need, as is evident in our work with eating disorders and the model of how it might be applied to a PTS population. The model takes advantage of databases and other digital resources to continuously expand and adapt approaches based on reach, engagement, efficacy, cost and other factors. In fact, groups working in a variety of different settings with similar populations might be able to share resources, observations, ideas, and approaches to improve programs and outcomes more quickly. There also are challenges to this approach, and we touch on some of the major ones here. We note that reach is a major issue in any consideration of the broad effectiveness of an intervention intended to serve a population (25). A problem of many interventions for trauma survivors, and especially of research studies conducted to evaluate interventions, is that only a very few members of the population of interest can participate in the interventions. For example, Shalev et al. (26) contacted 4,224 individuals within 3 weeks of experiencing a traumatic event. Individuals reporting distress who could attend traditional psychotherapy and did not have conflicting medical conditions were invited to treatment. Of those contacted, 73% were not eligible, 18% refused to participate, and 9% were invited to treatment. Price et al. (27) pointed out that a strength of technology-based interventions is the greater potential reach of services and relatively small number of exclusion criteria for participation. In their work with survivors of Hurricane Ike (2008) in Texas, their population was defined as those who were eligible (e.g., had an internet connection) and consented to the intervention (reach/ inclusion). Of 5,536 individuals who were contacted, 43% were not eligible, 4% refused to participate, and 23% of the total number of contacted individuals were invited to treatment. Thus, a major advantage of defined populations interventions that incorporate digital technologies is to increase reach and engagement. j A top-down approach. The model assumes that some group of individuals is managing the population toward the stated goals, and that the group has authority to modify various aspects of the system as a whole. Systematic interventions for individuals with PTS within a health care system Reach/engagement and effectiveness rates would be monitored and improved for each intervention based on ongoing reach, engagement and outcomes data, with interventions modified and new treatment options and supportive activities added as appropriate (e.g., asynchronous, synchronous on-line groups, face-to-face groups, family psychoeducational resources). Such monitoring data are likely to be eye opening. For instance, in an older study of 20,284 veterans newly diagnosed with PTSD, 50% (n=10,127) were prescribed a psychotropic medication but only 39% (n=7,980) received some counseling. Only 24% (n=1,909) of those who received any counseling had at least eight counseling sessions. In all, 33% (n=6,616) of those who received a diagnosis of PTSD received a minimally adequate treatment trial in the subsequent 6 months (22). If this population had been enrolled in a defined population model, then the focus might be on increasing counseling, which might have necessitated including other approaches more amenable to the population. For instance, increasing the number of individuals receiving any counseling might be achieved by adding teletherapy and blended programs to make access easier for enrollees. Such findings have led to attempts to increase the reach of evidence-based treatments in the VA (23). As with eating disorders, face-to-face treatments remain the dominant model of service delivery for PTS, and as with eating disorders, there are a variety of limitations of this treatment modality at present. First, although evidence- An HMO might engage in a more ambitious program of mhealth.amegroups.com mHealth 2018;4:25 mHealth, 2018 Page 9 of 13 activities that may work synergistically to enhance outcomes. trying to reduce PTS prevalence in the population. In this case, preventive and educational resources would be added to screening and other activities, as in the model shown in Figure 1. Screening itself could focus on exposure to recent traumatic events as well as PTS reactions. For those with no PTS symptoms, general information about how to be supportive of family members and other services would be provided. For those at risk for PTS (i.e., those recently exposed to traumatic events such as life-threatening illness, accidents, assault, or sudden death of a loved one), PTS prevention and brief intervention programs could be offered in emergency rooms (24) or in primary care settings. In theory, the effects of an integrated prevention and treatment program on the prevalence of PTS could be monitored by routine screening provided to the population. © mHealth. All rights reserved. mhealth.amegroups.com Benefits, challenges, and key questions for a systematic digital defined population approach This assumes an altruism that may not be realistic in many settings where the goal may be to reduce, rather than increase, utilization, and it may also assume a degree of managerial power and decision-making ability that may not be present. In the consumer world, where these models are widely practiced, increased sales are desired outcomes but there is often the assumption that this occurs through satisfied customers. The model we are proposing should have consumer and user input built into all aspects of decision-making and program deployment. In many mental health treatment systems, outcomes, engagement, and other key variables are not routinely monitored so that the impact of policy changes on effectiveness, reach, and engagement of treatment and prevention activities may remain unclear. Until the potential advantages of the system can be demonstrated— better population-wide outcomes and happier consumers— the model is unlikely to be adopted. Expense. The defined population model assumes that consumers would be provided resources based on interest. It is possible that the more expensive options (e.g., face- to-face therapy) would be preferred and population-wide screening is likely to generate large numbers of individuals who could overwhelm the system, stressing already limited services and increasing costs. An alternative is to use a stepped care model in which less expensive options are For PTS, within a digital strategy within a defined population that focuses on secondary prevention (e.g., education, well-being) of PTS problems for those exposed to trauma, interventions would be appropriate along with resources and activities to provide family support and education and other services to the population. By viewing the entirety of the population exposed to traumas, it becomes possible to envision a range of services and mhealth.amegroups.com mHealth 2018;4:25 Page 10 of 13 mHealth, 2018 actions among interacting teams. Data showing a range of outcomes associated with different screening and intervention components must be analyzed. Teams must use those data to make changes in various aspects of intervention delivery. Such changes may require training of providers as well as changes to software content. The effects of these changes on effectiveness, reach, and engagement must then also be assessed, and additional changes made in an iterative process. It is evident that this process is complex, involves significant personnel resources, and requires leadership buy-in and support. Benefits, challenges, and key questions for a systematic digital defined population approach It will be necessary to assemble teams with the requisite expertise, and establish procedures by which ongoing processes of data analysis and intervention redesign can be accomplished in the service of treatment improvement. The conditions necessary to assemble and operate such teams seems most likely to be achieved in health care systems that offer a comprehensive set of services that includes screening and multiple mental health treatment options. provided first (7). However, we believe there is a right to accessible, affordable, evidence-based care and that, as providers and researchers, we need to find ways to deliver these interventions. Privacy. The model is based on HIPAA protected information. Protecting participant privacy is essential, and any member of the defined population who wishes to opt out should be able to do so easily, with his/her data removed from the system. A number of measures would need to be taken to ensure that privacy rules and compliance with HIPPA are both followed. Software. Another major issue is the lack of standard software systems that facilitate rapid authoring and revision of interventions based on lessons learned during the monitoring process. One approach is to work with software developers to create management platforms that allow the outcomes optimization team to author and upload new content on an ongoing basis. However, this approach may warrant greater upfront costs than can be allocated, and still requires expenses over time to maintain and improve the technology. In disasters, most helping efforts go into secondary prevention, in which an attempt is made to assist an affected population in ways that prevent development of PTSD and other problems. In part because major disasters often affect large populations, disaster mental health response currently includes multiple aspects of a stepped care approach, including broad assistance for those affected via outreach programs and delivery of Psychological First Aid (PFA) (28), intermediate intensity crisis counseling services for those needing more support (29), and referrals for those requiring mental health treatment. These outreach, PFA, crisis counseling, and tertiary mental health treatments may be provided by a range of agencies contracted to mount a response in an affected area, with response capabilities distributed across a range of helping organizations rather than located within a single organization. Such a distribution means that systems of multi-organization collaboration will need to be established in order to implement systematic digital defined population interventions. © mHealth. All rights reserved. mHealth 2018;4:25 mhealth.amegroups.com Benefits, challenges, and key questions for a systematic digital defined population approach It will likely be necessary to designate and structure a leadership team charged with implementing the intervention system and an additional challenge will be to provide a suite of digital interventions across multiple organizational settings. Defined populations and outcomes. As specified throughout, a key factor is defining the population and outcomes. For example, does the group want to focus on reducing symptoms or another potentially relevant outcome, such as improving functioning? In the case of populations of trauma survivors, the primary needs might include not only symptom reduction, but also a focus on empowerment, employment, social support, political activism, or safety. Changes to interventions and the structure of the treatment system might differentially impact different kinds of outcomes. Additionally, in responding to traumatized populations, as with those affected by eating disorders, we are challenged to think about designing a model that addresses multiple, co-occurring problems, as is often the case for individuals with PTS. Using a systems approach to address this challenge means that defining the population includes: (I) identifying which groups of users are important to target (e.g., individuals with eating disorders, major depression, and generalized anxiety disorder, but not alcohol use disorder), (II) determining which interventions to offer and whether the model needs ordering rules for the timing of intervention delivery, and (III) agreeing on which outcomes will define success. It is also important to note that there have been many examples of defined population interventions for PTSD, though none to our knowledge have applied a systematic, outcome-oriented approach. For instance, Zatzick et al. (30) used a medical record to identify acutely injured trauma survivors who were then randomized to an intervention or Management of defined populations intervention systems. The approach advocated for here requires a centrally directed systematic approach to collaborative mhealth.amegroups.com mHealth, 2018 Page 11 of 13 Page 11 of 13 usual care and followed-for 6 months. Zatzick et al. (31) also examined reach and effect sizes to predict population-level benefits for two PTSD prevention approaches. Engel et al. (32) linked screening for PTSD in primary care settings to collaborative care facilitated by a nurse care manager. The VA has been at the forefront of providing training to providers in evidence-based care (33)—expanding the provider pool is a key step in any defined population intervention. Benefits, challenges, and key questions for a systematic digital defined population approach Other studies have examined components of a defined intervention model such as the effects of documenting PTSD best practices templates (34), the effectiveness of self-help (35), and many others. However, to our knowledge none have focused on the use of digital technology to enhance reach, engagement, and outcome in a dynamic way. of treatment. Overall, the approach is a way of bringing “measurement-based care” to the larger treatment system management enterprise—that is, to enable measurement- based management. Such an approach also presents significant obstacles. Health care organizations must reorganize aspects of their operations and assemble multidisciplinary teams to accomplish the various components. Top leadership must strongly support the system because it will be necessary to implement a series of practice changes in multiple sections of the organization as ongoing monitoring efforts lead to redesign of interventions. Implementation of the approach is likely to require significant personnel resources, as well as access to novel software systems. To some degree, large health care organizations may already contain many of the personnel resources and functional capabilities required for the defined populations methods suggested here, but they must be identified and brought together in a coordinated system of care. Despite these significant obstacles, we believe that a systematic digital population-based approach to mental health interventions holds promise for establishing significantly more effective treatment delivery systems, and most importantly, creating a more rapid and effective process of treatment improvement in health care systems and other delivery environments. y y Technology is important because of its capacity to increase the scope and efficiency of population-based interventions. It can enable rapid, continuous evaluation that includes outcomes data, but also detailed information about process variables. For example, it will be possible to determine when and where in technology-based interventions that dropout occurs. It can greatly increase the reach of services by more easily including low intensity interventions that can be accessed by large numbers of trauma-affected individuals. It enables cost-effective online screening of large numbers of individuals across geographic areas (36). It makes possible more rapid modification of interventions themselves and speeds processes of application of modified interventions by practitioners with less training burden. Technology also enables inclusion of a larger set of intervention types (e.g., blended interventions) and by strengthening delivery of self- help interventions, makes possible more easily delivered and effective stepped care models. Benefits, challenges, and key questions for a systematic digital defined population approach The model we are describing is certainly compatible with the RE-AIM (Reach, Effectiveness, Adoption, Implementation and Maintenance model) (37) and other implementation models, but also should make it easier to apply them. Footnote Conflicts of Interest: The authors have no conflicts of interest to declare. Ethical Statement: The engagement data reported in this paper was covered by Stanford University School of Medicine, IRB2826. Other data was obtained from the public domain. Conclusions Advantages of the population-based approach outlined here include a simultaneous focus on effectiveness, engagement, and reach; potential for identification and customization of interventions for specific subpopulations; and improved cost-effectiveness of services. The approach also offers potential for more thoughtful selection and testing of alternative treatment improvement strategies, focusing on aspects of engagement, screening methods, alternative interventions, and different combinations of elements Acknowledgements We want to thank Sarah E. Siegel. This work was supported in part by: (R01 MH100455), (T32 HL007456), (T32 HL130357), and (F32 HD089586). © mHealth. All rights reserved. References 1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Arlington, 2013:338-54. 2. Hudson JI, Hiripi E, Pope HG Jr, et al. The prevalence 2. Hudson JI, Hiripi E, Pope HG Jr, et al. The prevalence mhealth.amegroups.com mHealth 2018;4:25 mHealth 2018;4:25 Page 12 of 13 mHealth, 2018 USA and Germany: A Meta-analytic Review. Eur Eat Disord Rev 2012;20:1-8. and correlates of eating disorders in the National Comorbidity Survey Replication. Biol Psychiatry 2007;61:348-58. 15. Andrews G, Basu A, Cuijpers P, et al. Computer therapy for the anxiety and depression disorders is effective, acceptable and practical health care: An updated meta- analysis. J Anxiety Disord 2018;55:70-8. 3. Klump KL, Bulik CM, Kaye WH, et al. Academy for eating disorders position paper: Eating disorders are serious mental illnesses. Int J Eat Disord 2009;42:97-103. 4. Taylor CB, Bryson S, Luce KH, et al. Prevention of eating disorders in at-risk college-age women. Arch Gen Psychiatry 2006;63:881-8. 16. Melioli T, Bauer S, Franko DL, et al. Reducing eating disorder symptoms and risk factors using the internet: A meta-analytic review. Int J Eat Disord 2016;49:19-31. 5. Taylor CB, Kass AE, Trockel M, et al. Reducing eating disorder onset in a very high risk sample with significant comorbid depression: A Randomized controlled trial. J Consult Clin Psychol 2016;84:402-14. 17. Turgoose D, Ashwick R, Murphy D. Systematic review of lessons learned from delivering tele-therapy to veterans with post-traumatic stress disorder. J Telemed Telecare 2017:1357633X17730443. 18. Sadeh-Sharvit S, Kim JP, Darcy AM, et al. Subgrouping the users of a specialized app for eating disorders. Eat Disord 2018:1-12. 6. Eisenberg D, Nicklett EJ, Roeder K, et al. Eating disorder symptoms among college students: Prevalence, persistence, correlates, and treatment-seeking. J Am Coll Health 2011;59:700-7. 19. Prins A, Bovin MJ, Smolenski DJ, et al. The Primary Care PTSD Screen for DSM-5 (PC-PTSD-5): Development and evaluation within a veteran primary care sample. J Gen Intern Med 2016;31:1206-11. 7. Wilfley DE, Agras WS, Taylor CB. Reducing the burden of eating disorders: A model for population- based prevention and treatment for university and college campuses. Int J Eat Disord 2013;46:529-32. 20. Knaevelsrud C, Maercker A. Internet-based treatment for PTSD reduces distress and facilitates the development of a strong therapeutic alliance: a randomized controlled clinical trial. BMC Psychiatry 2007;7:13. 8. Jacobi C, Fittig E, Bryson SW, et al. Who is really at risk? References Identifying risk factors for subthreshold and full syndrome eating disorders in a high-risk sample. Psychol Med 2011;41:1939-49. 21. Kuester A, Niemeyer H, Knaevelsrud C. Internet-based interventions for postraumatic stress: A meta-analysis of randomized controlled trials. Clin Psychol Rev 2016;43:1-16. 9. Fitzsimmons-Craft EE, Firebaugh ML, Kass AE, et al. Implementing an Internet-Based Platform for Eating Disorder Screening, Prevention, and Treatment on College Campuses: Preliminary Results from a State-Wide Initiative. Psychol Serv. (In Press) 22. Spoont MR, Murdoch M, Hodges J, et al. Treatment receipt by veterans after a PTSD diagnosis in PTSD, mental health, or general medical clinics. Psychiatr Serv 2010;61:58-63. 10. Kass AE, Balantekin KN, Fitzsimmons-Craft EE, et al. The economic case for digital interventions for eating disorders among United States college students. Int J Eat Disord 2017;50:250-8. 23. Ruzek JI, Karlin BE, Zeiss A. Implementation of evidence- based psychological treatments in the Veterans Health Administration. In: McHugh RK, BarlowDH (eds). Dissemination and Implementation of Evidence-Based Psychological Interventions, New York: Oxford University Press, 2012:78-96. 11. Muir S, Newell C, Griffiths J, et al. MotivATE: A Pretreatment Web-Based Program to Improve Attendance at UK Outpatient Services Among Adults With Eating Disorders. JMIR Res Protoc 2017;6:e146. 24. Ruzek JI, Follette VM. Cognitive-Behavioral Therapies for Trauma. 2nd edition. New York: Guilford Press, 2006:433-62. 12. Karlin BE, Brown GK, Trockel M, et al. National dissemination of cognitive behavioral therapy for depression in the department of veterans affairs health care system: Therapist and patient-level outcomes. J Consult Clin Psychol 2012;80:707-18. 25. Koepsell TD, Zatzick DF, Rivara FP. Estimating the population impact of preventive interventions from randomized trials. Am J Prev Med 2011;40:191-8. 13. Muñoz RF. The Efficiency Model of Support and the Creation of Digital Apothecaries. Clin Psychol Sci Pract 2017;24:46-9. 26. Shalev AY, Ankri YL, Peleg T, et al. Barriers to Receiving Early Care for PTSD: Results From the Jerusalem Trauma Outreach and Prevention Study. Psychiatr Serv 2011;62:765-73. 14. Beintner I, Jacobi C, Taylor CB. Effects of an internet- based prevention programme for eating disorders in the 14. Beintner I, Jacobi C, Taylor CB. Effects of an internet- based prevention programme for eating disorders in the © mHealth. All rights reserved. mHealth 2018;4:25 mhealth.amegroups.com Page 13 of 13 mHealth, 2018 to Depression and Post-Traumatic Stress Disorder in Military Primary Care. Mil Med 2008;173:935-40. 27. Price M, Gros DF, McCauley JL, et al. © mHealth. All rights reserved. References Nonuse and Dropout Attrition for a Web-Based Mental Health Intervention Delivered in a Post-Disaster Context. Psychiatry 2012;75:267-84. 33. Karlin BE, Ruzek JI, Chard KM, et al. Dissemination of evidence-based psychological treatments for posttraumatic stress disorder in the Veterans Health Administration. J Trauma Stress 2010;23:663-73. 28. Vernberg EM, Steinberg AM, Jacobs AK, et al. Innovations in Disaster Mental Health: Psychological First Aid. Prof Psychol Ref Prac 2008;39:381-8. 34. Sripada RK, Bohnert KM, Ganoczy D, et al. Documentation of Evidence-Based Psychotherapy and Care Quality for PTSD in the Department of Veterans Affairs. Adm Policy Ment Health 2018;45:353-61. 29. Berkowitz S, Bryan R, Brymer M, et al. Skills for Psychological Recovery: Field Operations Guide. Available online: https://www.ptsd.va.gov/professional/manuals/ manual-pdf/SPR_Manual.pdf 35. Kuhn E, Kanuri N, Hoffman JE, et al. A randomized controlled trial of a smartphone app for posttraumatic stress disorder symptoms. J Consult Clin Psychol 2017;85:267-73. 30. Zatzick D, O'Connor SS, Russo J, et al. Technology- Enhanced Stepped Collaborative Care Targeting Posttraumatic Stress Disorder and Comorbidity After Injury: A Randomized Controlled Trial. J Trauma Stress 2015;28:391-400. 36. Leykin Y, Muñoz RF, Contreras O. Are consumers of internet health information “cyberchondriacs”? characteristics of 24,965 users of a depression screening site. Depress Anxiety 2012;29:71-7. 31. Zatzick DF, Koepsell T, Rivara FP. Using Target Population Specification, Effect Size, and Reach to Estimate and Compare the Population Impact of Two PTSD Preventive Interventions. Psychiatry 2009;72:346-59. 37. Glasgow RE, Vogt TM, Boles SM. Evaluating the public health impact of health promotion interventions: the RE- AIM framework. Am J Public Health 1999;89:1322-7. 37. Glasgow RE, Vogt TM, Boles SM. Evaluating the public health impact of health promotion interventions: the RE- AIM framework. Am J Public Health 1999;89:1322-7. 32. Engel CC, Oxman T, Yamamoto C, et al. RESPECT-Mil: Feasibility of a Systems-Level Collaborative Care Approach doi: 10.21037/mhealth.2018.05.06 Cite this article as: Taylor CB, Ruzek JI, Fitzsimmons-Craft EE, Graham AK, Balantekin KN. A systematic digital approach to implementation and dissemination of eating disorders interventions to large populations identified through online screening: implications for post-traumatic stress. mHealth 2018;4:25. mHealth 2018;4:25 mhealth.amegroups.com mhealth.amegroups.com
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Cockfighting in Javanese Muslim Society during the Nineteenth and the Early Twentieth Century
Journal of Indonesian Islam
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1 Parikshit Chakraborty, ―Social Impact of Cock Fight: The Study among the Santals,‖ Research Journal of Humanities and Social Sciences 9, 4 (2018), p. 754; Eric Cockfighting in Javanese Muslim Society DOI: 10.15642/JIIS.2021.15.2.359-386 Cockfighting in Javanese Muslim Society DOI: 10.15642/JIIS.2021.15.2.359-386 Cockfighting in Javanese Muslim Society during the Nineteenth and the Early Twentieth Century Adi Putra Surya Wardhana | ISI Surakarta, Indonesia Dennys Pradita | Universitas Jambi, Indonesia Fiqih Aisyatul Farokhah | IAI Tarbiyatut Tholabah Lamongan, Indonesia Andriyanto | Universitas Veteran Bangun Nusantara, Indonesia Corresponding author: adiputra.48697@gmail.com Adi Putra Surya Wardhana | ISI Surakarta, Indonesia Dennys Pradita | Universitas Jambi, Indonesia Fiqih Aisyatul Farokhah | IAI Tarbiyatut Tholabah Lamongan, Indonesia Andriyanto | Universitas Veteran Bangun Nusantara, Indonesia Corresponding author: adiputra.48697@gmail.com Abstract: This study aims to analyze the thoughts of Javanese Muslims on cockfighting in the nineteenth and the early twentieth centuries. It has been a custom and culture since humans domesticated chickens. At first, it had a sacred connotation. It eventually devolved into a profane gamble. Although Islam banned animals fighting and gambling, the tradition continued during the Islamic era. This study examines (1) the reasons why Javanese Muslim culture enjoys cockfighting, (2) the forms of Javanese Muslim thought about cockfighting in Javanese manuscripts from the nineteenth and the early twentieth centuries, (3) its influence on colonial and royal rule in Java. Research showed that some thoughts normalized cockfighting and cockfight gambling, but some viewed the game as an evil deed during the nineteenth and the early twentieth centuries. Keywords: Javanese Muslim, Cockfighting, Javanese manuscripts, Colonial Government 2 Parikshit Chakraborty, ―Historic Cock Fight among the Santals: An Anthropological View,‖ Social Science & Humanities International 2, 1 (2018), p. 14. 3 Csapo, ―Deep Ambivalence, pp. 10-16. 4 Parikshit Chakraborty and Falguni Chakrabarty, ―Cock Fight: A Symbolic View of Social Status,‖ International Journal of Social Science 6, 1 (2017), p. 39; Parikshit Chakraborty, ―Cock Fight: The Flow of Blood,‖ The Asian Man, an International Journal 13, 1 (2019), pp. 95-96; Parikshit Chakraborty and Falguni Chakrabarty, ―Social-Cultural Aspects of Cock Fight: A Study among the Santals of Foringdanga, Paschim Medinipur, West Bengal, India,‖ Imperial Journal of Interdisciplinary Research 2, 10 (2016), p. 2116. Csapo, ―Deep Ambivalence: Notes on a Greek Cockfight (Part I),‖ Phoenix 47, 1 (1993), p. 8. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 Introduction Cockfighting is a culture found in various parts of the world. It was popular in Europe, Asia, and America from the sixteenth century to the twentieth century. It has been found in Greece since Themistocles (524–460 BCE). It was related to the activities of religious rituals and political institutions in Athens, Greece.1 During JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 359 Adi Putra Surya Wardhana, Dennys Pradita, Fiqih Aisyatul Farokhah, and Andriyanto the Christian era, the Christian clergy opposed this tradition was. However, it continued to spread to Italy, Germany, Spain, and their colonies, including England, Wales, Ireland, and Scotland.2 Cock- fighting is a symbol of the fighting spirit in Greek culture. The chicken is interpreted as a symbol of sexuality and masculinity. Therefore, the cockfighting ritual represents both military and sexual conquest.3 In India, Cockfighting is also practiced. The Harappa culture, which flourished in the Indus River Valley between 2500-2100 BCE, is credited with starting this custom. Since 1000 BCE, cockfighting has had religious significance for the people of the Indus River Valley. It developed in the West Bengal region of India. It was also popular in China, Persia, and other Eastern countries at the time. 4 Cockfighting became an arena to protect territory and family pride since the rooster symbolized courage and resistance.5 Cockfighting has become universal that has spread throughout Southeast Asia, including the Nusantara (Indonesian archipelago). g p g This culture can be traced back to the Javanese domestication of chickens in Nusantara. Evidence of the domestication of chickens (Gallus gallus) is carved in the reliefs of Borobudur Temple.6 Reid recorded Hindu-Buddhist inscriptions in Java that described the religious culture of cockfighting, an essential part of temple feasts, ordinations, and pilgrimages. The blood of a rooster 5 Chakraborty and Chakrabarty, ―Cock Fight: A Symbolic View of Social Status, p. 40. 6 Bambang Agus Suripto and Listia Pranowo, ―Relief Jenis-Jenis Fauna Dan Setting Lingkungannya Pada Pahatan Dinding Candi Borobudur,‖ Manusia Dan Lingkungan 8, 1 (2001), p. 41. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 360 Cockfighting in Javanese Muslim Society means a sacrifice to the gods. Cockfighting took place in certain villages, shrines, and festivals. 8 Sophia Raffles, Memoir of the Life and Public Services of Sir Thomas Stamford Raffles (London: William Clowes and Sons, 1835), p. 333. 9 Thomas Stamford Raffles, The History of Java (London: Black Parbury and Allen Booksellers to the Hon, 1817), p. 249 and p. 349. In Sumatra, the culture of cockfighting was favored by the Minangkabau people, although the Padri (religionists) group disliked it in the 19th century. 7 Anthony Reid, Southeast Asia in the Age of Commerce, 1450-1680 (Volume One: The Lands below the Winds) (New Haven and London: Yale University Press, 1988), p. 189. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 8 Sophia Raffles, Memoir of the Life and Public Services of Sir Thomas Stamford Raffles (London: William Clowes and Sons, 1835), p. 333. Introduction The kingdoms in Java also held cockfighting as a royal prerogative, either for fertility rituals or ceremonies for success in war.7 Since the thirteenth century, Islamic political forces have grown. The Hindu-Buddhist kingdoms were in decline in the fifteenth century. Islam spread rapidly in Java. Islamic dynasties ruled over Java in the sixteenth century. New values and norms (Islam) influenced the cockfighting culture. Islamic religious dogmas prohibited cockfighting activities. In Islamic teachings, fighting animals is a terrible deed, and cockfighting is mainly used for gambling. The cockfighting was also detested by the British colonial authority since it was not in keeping with the British character.8 y p g However, cockfighting remained a popular game in Java during the colonial era. Thomas Stamford Raffles in The History of Java recorded áduh jágu (cockfighting), a common game among ordinary people. The cockfighters add the spurs to make the game enjoyable. 9 For a hedonistic society, the function of the cockfighting ritual has shifted to gambling. Gambling in Javanese is called botoh, while rooster in Javanese is called sawung. In the old Javanese language, sawung also refers to cockfighting. The Javanese people still use this word. Both sawung and sabung mean cockfighting. Even though cockfighting does not necessarily involve gambling, the definition of sabung ayam has been characterised as cockfighting gambling. The social context of botoh sawung (cockfighting gambling) as a game of pleasure and gambling influenced the writing of Javanese manuscripts. Several manuscripts, including Serat Centhini, Pranacitra (Rara Mendut), Serat Tatacara, and Serat Adu Jago, record the Javanese people‘s preference for cockfighting during the Islamic period. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 361 Adi Putra Surya Wardhana, Dennys Pradita, Fiqih Aisyatul Farokhah, and Andriyanto Meanwhile, there are also regulatory texts regarding botoh sawung (cockfighting gambling), such as Serat Angger Pradata Awal Kasultanan Yogyakarta and Pranatan Pulisi Tumrap Băngsa Jawi ing Indiya Nèdêrlan, H. Buning, 1913 (Algemeene Politie Reglement voor de Inlanders in Nederlandsch-Indie). The texts reveal that cockfighting is popular among the Javanese, despite the fact that it is prohibited by religion and the government. Meanwhile, there are also regulatory texts regarding botoh sawung (cockfighting gambling), such as Serat Angger Pradata Awal Kasultanan Yogyakarta and Pranatan Pulisi Tumrap Băngsa Jawi ing Indiya Nèdêrlan, H. Buning, 1913 (Algemeene Politie Reglement voor de Inlanders in Nederlandsch-Indie). 10 Chakraborty, ―Social Impact of Cock Fight: The Study among the Santals; Chakraborty, ―Historic Cock Fight among the Santals: An Anthropological View; Chakraborty and Chakrabarty, ―Social-Cultural Aspects of Cock Fight; Chakraborty and Chakrabarty, ―Cock Fight: A Symbolic View of Social Status; Chakraborty, ―Cock Fight: The Flow of Blood.‖ 11 Wanni Wibulswasdi Anderson, ―Beyond The Cockfight: Masculinity and the Thai Dove-Cooing Contest,‖ Manusya: Journal of Humanities 8, 3 (2005), p. 86. 10 Chakraborty, ―Social Impact of Cock Fight: The Study among the Santals; Chakraborty, ―Historic Cock Fight among the Santals: An Anthropological View; Chakraborty and Chakrabarty, ―Social-Cultural Aspects of Cock Fight; Chakraborty and Chakrabarty, ―Cock Fight: A Symbolic View of Social Status; Chakraborty, ―Cock Fight: The Flow of Blood.‖ 11 Wanni Wibulswasdi Anderson, ―Beyond The Cockfight: Masculinity and the Thai Dove-Cooing Contest,‖ Manusya: Journal of Humanities 8, 3 (2005), p. 86. 12 Garry Marvin, ―The Cockfight in Andalusia, Spain: Images of the Truly Male,‖ Anthropological Quarterly 57, 2 (1984), p. 60. 13 Samuel J. Walker and Hanneke J.M. Meijer, ―More than Food; Evidence for Different Breeds and Cockfighting in Gallus Gallus Bones from Medieval and Post-Medieval Norway,‖ Quaternary International (2020), pp. 1-10. 13 Samuel J. Walker and Hanneke J.M. Meijer, ―More than Food; Evidence for Different Breeds and Cockfighting in Gallus Gallus Bones from Medieval and Post-Medieval Norway,‖ Quaternary International (2020), pp. 1-10. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 2 12 Garry Marvin, ―The Cockfight in Andalusia, Spain: Images of the Truly Male,‖ Anthropological Quarterly 57, 2 (1984), p. 60. Introduction The texts reveal that cockfighting is popular among the Javanese, despite the fact that it is prohibited by religion and the government. Therefore, this study examines cockfighting in Javanese Muslim society during the 19th and early 20th centuries C.E. Some of the problems discussed in this study are (1) the cause of the Javanese Muslim society enjoys cockfighting, (2) the forms of Javanese Muslim thought on cockfighting found in Javanese manuscripts during the 19th and early 20th centuries (3) the influence of cockfighting on the rules of the Colonial Government and the Kingdom of Java. g Several studies related to cockfighting serve as a literature review in this study. Some of Chakraborty‘s ethnographic studies are a good example.10 He examined the culture of cockfighting in India that emerged since humans domesticated chickens. However, he did not examine the Muslim society‘s view on this tradition. Then, Anderson analyzed the concept of cockfighting masculinity in Thailand. 11 Marvin analyzed cockfighting as a symbol of mascu- linity in Spain.12 Walker and Meijer studied evidence of cockfighting in Medieval and Post-medieval Norway. 13 Sykes examined the specialty of roosters and the culture of cockfighting in Europe, JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 362 Cockfighting in Javanese Muslim Society especially in Roman Britain. 14 Meanwhile, O‘Donnel and Smith criticized the research conducted by Geertz on the cockfighting tradition in Bali.15 These studies did not examine Javanese Muslim thoughts on cockfighting or cockfighting gambling. The number of Research done on the thoughts of Javanese Muslims about botoh sawung is very limited. Therefore, this research deserves to be conducted to fill the void of intellectual historiography about Javanese Muslim thought on cockfighting from the nineteenth century to the early twentieth centuries. This research is arranged by collecting data sources, conducting internal and external criticism, interpreting the data, and compiling the interpretation results in an empirical narrative. It uses data in the form of text in Javanese manuscripts on cockfighting and botoh sawung. This study used a history of thought or intellectual approach to examine the thoughts of the Javanese Muslim society about cockfighting followed by gambling. The study of thought history is a part of an attempt to understand the human experience. This approach is used to examine how people in the past understand ideas, thoughts, arguments, beliefs, assumptions, attitudes, and preoccupations that shaped the intellectual life of society. 14 Naomi Sykes, ―A Social Perspective on the Introduction of Exotic Animals: The Case of the Chicken,‖ World Archaeology 44, 1 (2012), p. 158. 15 Philip Smith, ―The Balinese Cockfight Decoded: Reflections on Geertz, the Strong Program and Structuralism,‖ Cultural Sociology 2, 2 (2008), pp. 169–186; Casey O‘Donnell, ―On Balinese Cockfights: Deeply Extending Play,‖ Games and Culture 9, 6 (2014), pp. 406–16. 16 Stefan Collini, ―What Is Intellectual History...?,‖ Juliet Gardiner (ed.), What Is History Today? (Hampshire and London: The Macmillan Press Ltd., 1988), p. 105. Introduction Intellectual history aims to analyze selected texts in depth.16 In this study, intellectual history is used to analyze texts about botoh sawung in the thought of the Javanese Muslim society during the nineteenth century and early twentieth century. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 17 Dennys Pradita, ―Pemikiran Konservasi Burung Di Indonesia Tahun 1894 Sampai 1970an: Dari Kesadaran Kultural Ke Kesadaran Lingkungan‖ Unpublished Master Thesis, Universitas Gadjah Mada Yogyakarta (2020), p. 68. 18 Clifford Geertz, ―Deep Play: Notes on the Balinese Cockfight,‖ Daedalus 101, 1 (1972), pp. 1-37. 20 Suripto and Pranowo, ―Relief Jenis-jenis Fauna dan Setting Lingkungannya, p. 41. Tracing the Genealogy of Cockfighting Chicken (Gallus) are a type of bird that can be domesticated or live in the wild. Chickens have a unique value for the people of JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 363 Adi Putra Surya Wardhana, Dennys Pradita, Fiqih Aisyatul Farokhah, and Andriyanto Adi Putra Surya Wardhana, Dennys Pradita, Fiqih Aisyatul Farokhah, and Andriyanto Nusantara. In some rituals, chicken is used as an offering. The people of Sumba (East Nusa Tenggara) interpret chickens as sacrifices for rituals.17 The people of Sumbawa (West Nusa Teng- gara) use chicken as an offering at a Megalithic site. The ritual of slaughtering chickens is carried out before the planting season, around November. Meanwhile, Balinese people usually sacrifice chickens in the Shiva Tattwa Purana ritual (the ancient story of Siva‘s essence) as birth to death rituals. The tradition of cockfighting for rituals in Bali is called Tajen.18 Cockfighting has the meaning of death, virility, anger, pride, loss, and virtue among the Balinese.19 The blood drops symbolize a plea for humanity to avoid harm. The chicken is a significant animal in religious life not only for Sumbanese, Sumbawanese, and Balinese, but also for the Javanese. The proof is the temple reliefs on Java which show the figure of a rooster, such as the relief of a chicken at Borobudur Temple,20 the rooster medallion relief at Panataran Temple (12nd – 15th century),21 and the rooster medallion at Kidal Temple, Malang (13th century).22 The reliefs of cockfighting in Rimbi Temple. The rooster medallion is not only a temple ornament but also a symbol of life because the rooster always crows at sunrise and is beneficial for human life as livestock. The medallion is a sign of strength and courage. The chicken has a mystical connotation in the Javanese Hindu-Buddhist culture since it is often frequently used as a sacrificial animal in rituals. The rooster is not only 21 Ranang Agung Sugihartono and Handriyotopo, Transisi: Wayang, Relief, Dan Animasi (Surakarta: ISI Press, 2017), p. 9. 22 Ulfatun Nafi‘ah et.al., ―Perancangan Motif Batik dengan Inspirasi Relief Ornamentasi Candi Kidal sebagai Pengembangan Corak Batik Desa Kidal,‖ Jurnal Praksis Dan Dedikasi Sosial 1, 2 (2018), p. 114. 22 Ulfatun Nafi‘ah et.al., ―Perancangan Motif Batik dengan Inspirasi Relief Ornamentasi Candi Kidal sebagai Pengembangan Corak Batik Desa Kidal,‖ Jurnal Praksis Dan Dedikasi Sosial 1, 2 (2018), p. 114. 19 Smith, ―The Balinese Cockfight Decoded, p. 174. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 17 Dennys Pradita, ―Pemikiran Konservasi Burung Di Indonesia Tahun 1894 Sampai 1970an: Dari Kesadaran Kultural Ke Kesadaran Lingkungan‖ Unpublished Master Thesis, Universitas Gadjah Mada Yogyakarta (2020), p. 68. 18 Clifford Geertz, ―Deep Play: Notes on the Balinese Cockfight,‖ Daedalus 101, 1 (1972), pp. 1-37. 19 Smith, ―The Balinese Cockfight Decoded, p. 174. 20 Suripto and Pranowo, ―Relief Jenis-jenis Fauna dan Setting Lingkungannya, p. 41. 21 Ranang Agung Sugihartono and Handriyotopo, Transisi: Wayang, Relief, Dan Animasi (Surakarta: ISI Press, 2017), p. 9. 22 Ulfatun Nafi‘ah et.al., ―Perancangan Motif Batik dengan Inspirasi Relief Ornamentasi Candi Kidal sebagai Pengembangan Corak Batik Desa Kidal,‖ Jurnal Praksis Dan Dedikasi Sosial 1, 2 (2018), p. 114. 18 Clifford Geertz, ―Deep Play: Notes on the Balinese Cockfight,‖ Daedalus 101, 1 (1972), pp. 1-37. 21 Ranang Agung Sugihartono and Handriyotopo, Transisi: Wayang, Relief, Dan Animasi (Surakarta: ISI Press, 2017), p. 9. 17 Dennys Pradita, ―Pemikiran Konservasi Burung Di Indonesia Tahun 1894 Sampai 1970an: Dari Kesadaran Kultural Ke Kesadaran Lingkungan‖ Unpublished Master Thesis, Universitas Gadjah Mada Yogyakarta (2020), p. 68. 23 Reid, Southeast Asia in the Age of Commerce, p. 6. 24 Ibid., p. 183. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 23 Reid, Southeast Asia in the Age of Commerce, p. 6. 25 Ibid., p. 189. 26 The original version in Javanese says: ―Sang Narendra Anusapati dhawuhnya, mring abdi gadhuh pitik, kinèn umêndhêta, sawung adon sajuga, wus inêndhêt gya tinandhing, samya binolang, pyambak tajine mranti. Rame tarungira sawung sakalihan, sang nata lenèng galih, kasalamur loknya, datan mawi nglagewa, Sang Panji Tohjaya aglis, narik curiga, yasanya Êmpu Gandring....‖ See R.M. Mangkudimedja, Serat Pararaton (Jakarta: Proyek Penerbitan Buku Sastra Indonesia dan Daerah, 1979), pp. 69–70. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 Tracing the Genealogy of Cockfighting JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 364 Cockfighting in Javanese Muslim Society worshipped or sacrificed in rituals but is also participated in cockfighting as part of sacred ceremonies. Picture 1. Rooster Medallion at Penataran Temple Source: https://telusuri.id/cara-candi-penataran-mengawetkan-hewan/ (accessed on 14 August 2021) Picture 1. Rooster Medallion at Penataran Temple Source: https://telusuri.id/cara-candi-penataran-mengawetkan-hewan/ (accessed on 14 August 2021) The tradition of cockfighting is known as adu jago or ngaben sawung (sabung). According to Reid, the cockfighting ritual spread throughout the mainland of Southeast Asia. 23 Each region has different roots or meanings for cockfighting and it evolves over time. Reid picks up a common thread regarding cockfighting in Southeast Asia. Every feast day in Southeast Asia, it is frequently held as a show and spectacle in public places such as markets or other crowded centers.24 24 Ibid., p. 183. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 365 27 Jan Wisseman Christie, Register of the Inscriptions of Java 732-1060 A.D. (The Inscriptions of Mataram (1999), p. 209. 28 The original version in Javanese says: ―…masiwo manigel manawun karun hayam. kapua mahyun tanda rakryan maguyuguywan umarsukhamwak nikanan rāma i sampun tanda rakryān masawunan manigal ikanan rama kabaih molih.‖ JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 Adi Putra Surya Wardhana, Dennys Pradita, Fiqih Aisyatul Farokhah, and Andriyanto Adi Putra Surya Wardhana, Dennys Pradita, Fiqih Aisyatul Farokhah, and Andriyanto Adi Putra Surya Wardhana, Dennys Pradita, Fiqih Aisyatul Farokhah, and Andriyanto Meanwhile, in ancient Java, cockfighting was practiced in specific communities, sacred places, and festivals. The court nobles held cockfights exclusively for fertility rituals and ceremonies for success in war. 25 Therefore, cockfighting had the nature of ritual and pleasure simultaneously. Perhaps in ancient Java, the pleasure of cockfighting was wrapped in religious discourse. The story of cockfighting in ancient Java was also found in Serat Pararaton. The manuscript, rewritten in 1912, told the story of King Singasari, who was killed during a cockfight. King Anusapati was a king who liked cockfighting. The king sent an exceptional servant to take care of the rooster and train his domestic rooster to be outstanding fighting cocks. Because the roosters were so enormous, the cock keeper was overwhelmed when it came to selecting and preparing the rooster. ―King Anusapati gave orders to the caretaker of the royal rooster. The caretaker took the rooster for a long time because he had to choose the best fighting cock. After taking, (the rooster) was pitted; alternately, the iron stuck in the chicken‘s leg targeting everywhere. The cockfighting went lively. The king enjoyed according to his heart‘s desire. The cockfighting made him complacent. Unknowingly, Sang Panji Tohjaya immediately pulled the weapon (keris) made by Mpu Gandring.‖26 According to the manuscript, cockfighting was a pleasure and a spectacle for the life journey in ancient times. The king was said to be complacent when cockfighting. The king‘s rooster was an attraction for the people; thus, he was careless. When all were mesmerized by the show, a keris (traditional Javanese dagger) pierced the king‘s skin. King Anusapati died immediately. This story was passed down orally and in writing from generation to generation. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 366 27 Jan Wisseman Christie, Register of the Inscriptions of Java 732-1060 A.D. (The Inscriptions of Mataram (1999), p. 209. Cockfighting in Javanese Muslim Society Cockfighting in Javanese Muslim Society Cockfighting in Javanese Muslim Society Serat Pararaton became a royal reading in Bali after the Hindu- Buddhist kingdoms in Java fell. The Pararaton manuscript had undergone a process of copying and translation since it was found by J.L.A. Brandes in the 1890s. The manuscript was also translated into Javanese. In Javanese terms, the process of copying the manuscript is called mutrani. According to several stories of the Hindu-Buddhist period, there were noble groups who had a penchant for sawung. Another inscription mentioning the existence of cockfighting in Java is the Taji Inscription. It was discovered in Ponorogo and is thought to have been written in 901 CE. Sawung or manawung karung hayam held at the Sima establishment ceremony. The cockfighting was made more exciting by the presence of dance, food, and drinks.27 ―... Playing, dancing, competing with wild boars and roosters, Tanda Rakryan, wanted to make jokes to make the village officials happy after Tanda Rakryan gathered to dance for four around. It represents a warning from the ruler to its citizens always to be careful and alert when having fun in cockfighting gambling.‖28 An inscription mentioning cockfighting gambling is contained in the Leran inscription. The inscription emphasises the importance of vigilance in cockfighting because it is prone to cheating. It represents a warning from the kingdom to its citizens always to be careful and alert when having fun in cockfighting gambling in the old Javanese era. ―People struggle with all bets with big prizes in gambling games regulated by gambling controllers must be watched carefully. They also cheat in the cockfighting game, either without or using spurs in a cockfighting place in case it can be a month of misfortune. Thus, it causes a loss of honor. Step back from the crowd, play gending (traditional percussion music), take a breath, walk around, then row carrying a wajon, JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 367 Adi Putra Surya Wardhana, Dennys Pradita, Fiqih Aisyatul Farokhah, and Andriyanto and cover the poles with a covering cloth like a nagapuspa (a kind of tree, Mesua Roxburghii).‖ 29 Therefore, cockfighting gambling needs to be regulated by the government. Several ancient inscriptions attested to the role of rulers in regulating gambling. According to some ancient inscriptions, a royal official (Mangilala drwya haji) took care of gambling. 29 The original version in Javanese says: ―…sama sanak anlanakna salwiranin. totohan. mahadinita. judi. paparihan. gawur. sahawasanya. muwah. anadwa sawun a tajya tajyana. satajyanya. sawulananya dainya. tlas nin puja pwa. munduraramya ramyana. agdin gendina. awaywa waywana. mideren banjar. pamikulakna wajon. sawadahanya. anulesana pikulan sahulesanya. makadi nagapuspa....‖ 30 Shafrina Fauzia, ―Sabung Ayam di Jawa dan Bali dalam Data Prasasti,‖ Prajnaparamita Jurnal Museum Nasional (2018), p. 98 JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 31 Dennys Pradita, ―Mitologi Sampai Perdagangan: Status, Peran, dan Makna Burung dalam Masyarakat Jawa dari Zaman Kolonial Hingga Milenial,‖ Pramana Yuda (ed.), Konferensi Peneliti dan Pemerhati Burung (KPBBI ) IV Semarang (2018), pp. 388-402. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 Cockfighting in Javanese Muslim Society Wangwang Bangen (746 Śaka), Kuti (762 Śaka), Gandakuti (964 Śaka), Talan (1058 Śaka), and Waringin Pitu (1369 Śaka) inscriptions mention juru judi (overseer of gambling). Juru judi acts as leaders, heads, and overseers within the kingdom that collects gambling taxes. The inscriptions of Biluluk IV, Pabuharan, Waharu I, Padlegan, and Lordaru (1245 Śaka) mention the tuha judi (head of gambling) profession. Their job is the same as that of a juru judi. The Pabuharan, Kuti, Gandakuti, Pupus (1022 Saka), Lordaru, and Wangwang Bangen inscriptions mention the malandan profession whose job is to oversee and arrange the gambling. Malandan took a ten percent stake in a cockfighting or gambling. There is also a lca profession which is an assistant gambling supervisor. Cockfighting gambling regulators are called lĕbĕlĕb. The profession of lĕbĕlĕb was often written with the profession of malandan and lca. The three professions are interrelated and important in gambling. There is a taji profession that makes and installs sharp weapons in chicken legs for cockfighting. Taji can also collect taxes on sharp weapon installations. 30 This reality shows that cockfighting and gambling contain power relations. Cockfighting is more than just a form of entertainment; it is a political discourse built by the authorities to show their strength. Therefore, the nobles always competed to have the best fighting cock. The ownership of fighting cocks became a symbol of social status among the nobility. Of course, the king‘s fighting cock must be the strongest. The king‘s charisma was at stake through his JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 368 32 Merle C. Ricklefs, Mystic Synthesis in Java: A History of Islamization from the Fourteenth to the Early Nineteenth Centuries (Norwalk: EastBridge, 2006), pp. 5, 20. 33 Ibid., p. 187. 34 Jochem van den Boogert, ―Rethinking Javanese Islam Towards New Descriptions of Javanese Traditions,‖ Ph.D Dissertation, Universiteit Leiden (2015), p. 353. 35 Andrea Acri and Verena Meyer, ―Indic-Islamic Encounters in Javanese and Malay Mystical Literatures,‖ Indonesia and the Malay World 47, 139 (2019), p. 280. 36 Clifford Geertz, The Religion of Java (Chicago and London: The University of Chicago Press, 1976), p. 5. Cockfighting in Javanese Muslim Society Cockfighting in Javanese Muslim Society fighting cock. It caused a sentiment among the royal elite. After the ownership of fighting cocks became a prestige, the meaning of cockfighting changed. At first, cockfighting was used to replace war. Cockfighting has resulted in fights throughout its history. This incident often happened after cockfighting had become gambling. Owning a fighting cock became economically valuable because it used bets. Picture 2. Illustration of cockfighting in Java c. 1596 CE Source: Atlas of Mutual Heritage, https://data.collectienederland.nl (accessed on 14 August 2021). Picture 2. Illustration of cockfighting in Java c. 1596 CE Source: Atlas of Mutual Heritage, https://data.collectienederland.nl (accessed on 14 August 2021). Cockfighting is a way for court officials or relatives to express their masculinity and channel their hobbies. It provides an overview or common thread regarding the concept of satisfaction or pleasure for Javanese men. Some satisfaction or symbols of perfection in Javanese men are wanita (woman), wisma (house), turangga (horse), curiga (kris), and kukila (bird). Kukila or bird refers to klangenan (pleasure) which has a deep meaning in Javanese thought. For Javanese men, klangenan can be a chirping bird or a fighting animal. It provides satisfaction or masculinity values for the owners. 31 Cockfighting in Javanese society did not only refer to a hobby but JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 369 Adi Putra Surya Wardhana, Dennys Pradita, Fiqih Aisyatul Farokhah, and Andriyanto also prestige for the owners. The owner felt ―manly‖ because they had a reliable fighting animal and pride. However, gambling is a harmful act according to the Purwadhigama state totohan pranidan totohan tan prani. It indicates moral teaching that humans should avoid gambling because it will bring misery. Cockfighting gambling remained popular through the centuries, the aspects of fun, entertainment, and politics behind it dominated more than the teachings of wisdom. 34 Jochem van den Boogert, ―Rethinking Javanese Islam Towards New Descriptions of Javanese Traditions,‖ Ph.D Dissertation, Universiteit Leiden (2015), p. 353. 32 Merle C. Ricklefs, Mystic Synthesis in Java: A History of Islamization from the Fourteenth to the Early Nineteenth Centuries (Norwalk: EastBridge, 2006), pp. 5, 20. 33 Ibid., p. 187. 35 Andrea Acri and Verena Meyer, ―Indic-Islamic Encounters in Javanese and Malay Mystical Literatures,‖ Indonesia and the Malay World 47, 139 (2019), p. 280. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 36 Clifford Geertz, The Religion of Java (Chicago and London: The University of Chicago Press, 1976), p. 5. 37 Robert W. Hefner, ―Where Have Athe Abangan Gone? Religionization and the Decline of Nonstandard Islam in Contemporary Indonesia,‖ Michel Picard and Rémy Madinier (eds), The Politics of Religion in Indonesia: Syncretism, Orthodoxy, and Religious Contention in Java and Bali (London & New York: Routledge, 2011), p. 72. 38 Koentjaraningrat, Kebudayaan Jawa (Jakarta: Balai Pustaka, 1994), p. 312. 39 Mark Woodward, Java, Indonesia, and Islam (London & New York: Springer Dordrecht Heidelberg, 2011), p. 115. 40 Andrew Beatty, Varieties of Javanese Religion: An Anthropological Account (Cambridge: Cambridge University Press, 2003), p. 158. 37 Robert W. Hefner, ―Where Have Athe Abangan Gone? Religionization and the Decline of Nonstandard Islam in Contemporary Indonesia,‖ Michel Picard and Rémy Madinier (eds), The Politics of Religion in Indonesia: Syncretism, Orthodoxy, and Religious Contention in Java and Bali (London & New York: Routledge, 2011), p. 72. 38 Koentjaraningrat, Kebudayaan Jawa (Jakarta: Balai Pustaka, 1994), p. 312. 39 Mark Woodward, Java, Indonesia, and Islam (London & New York: Springer Dordrecht Heidelberg, 2011), p. 115. 40 Andrew Beatty, Varieties of Javanese Religion: An Anthropological Account (Cambridge: Cambridge University Press, 2003), p. 158. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 Cockfighting in Javanese Muslims’ Thought g g J g Islam developed rapidly during sixteenth-century in Java. The Kingdom of Demak and Mataram (Islam) had an essential role in the Islamization of Java. Sufism influenced both Demak and Mataram. Islamic mysticism or Sufism became the dominant sect in Java. This sect was quickly accepted because pre-Islamic mystics still influenced Javanese society.32 The Javanese accepted the five pillars of Islam but still adhered to customs and mystical traditions. Therefore, Ricklefs used the term ‗mystic synthesis to describe this reality.33 The term Kejawen (Javanism) and Islamic-Javanese syncretism is quite problematic. Boogert criticized this conceptualization because syncretic was a complicated term.34 Acri and Meyer also disputed the conceptuali- zation of Javanism as part of the influence of the Hindu-Buddhist system.35 According to some researchers, Javanese Islam was separated from pure Islam (kaffah). Geertz called Javanese Muslims, abangan Islam, are different from Islam putihan (santri). 36 Hefner chose the JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 370 Cockfighting in Javanese Muslim Society Cockfighting in Javanese Muslim Society term abanganism.37 Koentjaraningrat gave the term specifically agami Jawi (Javanese religion).38 Woodward used the term Muslim Kejawen.39 Beatty chose Javanism as a term to distinguish between Javanist mysticism and the practice of Islam. 40 These researchers negate the fact that the adherents of Javanese Islam were Islam itself. They classified the belief systems and customs of the Javanese Muslim society through the perspective of orientalism. There were no Muslims in Java. The Javanese people practiced Islam which was reflected in their culture. Javanese people professed and practiced Islamic teachings while preserving their cultural traditions. Religion and culture were no longer divided and contrasted in Javanese Muslim society. Cockfighting is one of the problematic Javanese traditions when it comes to the interaction between religion and culture. Cockfighting is a popular pastime among Javanese. Islam, on the other hand, is a religion that rejects animal fighting. During the nineteenth to the early twentieth centuries, Javanese Muslim groups in rural and urban regions loved cockfighting. Javanese poets recorded their thoughts on cockfighting in texts written between the nineteenth to the twentieth centuries. Serat Centhini is one of the manuscripts documenting cockfighting as a favorite of the Javanese Muslim society. It was composed by Kanjeng Gusti Pangeran Adipati Anom Amangkunagara III (Sunan Paku Buwana V) in 1814 CE. In Serat Centhini (Suluk Tambangraras), the poem of Dhandhanggula canto 618 tells of a wedding celebration. The celebration was marked by the teaching Islamic natural studies. The event was enlivened up in 40 Andrew Beatty, Varieties of Javanese Religion: An Anthropological Account (Cambridge: Cambridge University Press, 2003), p. 158. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 371 Adi Putra Surya Wardhana, Dennys Pradita, Fiqih Aisyatul Farokhah, and Andriyanto the afternoon with cock and quail fighting. The evening‘s festivities included tayub dancers (ronggeng).41 The narration in stanzas 84 and 85 tells of a wedding party enlivened by a lively cock and quail fighting. In the next stanza, cock and quail fights were followed by botohan (gambling). ―Both sliced through the will, battling the cock without disappointment. The fighting cock was skilled at gripping, making the match fun, looking without being burdensome, and not dull. The muscles and bones hit vital points and airways without loosening the spirit already in your grip. Angling Derma and Ki Amat Supi pitted the rooster, explaining its superiority and belittling the others. 41 Kangjêng Gusti Pangeran Adipati Anom Amêngkunagara III (Ingkang Sinuhun Pakubuwana V), Serat Centhini (Yogyakarta: Yayasan Centhini, 1992). Dhandhanggula, canto 618, stanzas 84-85. 42 The original version in Javanese says: ―(91) Wong kalih kang liningan mangarsi, anandhing sawung datan kuciwa, prigêl nêkêm pambobote, kinarya nandhing mathuk, liring mathuk datan ngêboti, tan kadhih ing sausap, otot balungipun, myang gring-warase tan inang, pangiringing napas tan iwir mèlèdi, wus anèng têkêmira; (92) Angling Dêrma lan Ki Amat Supi, panandhingirèng sata satata, mêdharakên pigunane, panglamakira rampung, sinaoskên mring pra priyayi, tan wus sama ababag, rinamèkkên sampun, botoh kakalih turira, kang punika sampun (ng)gèn-kawula nandhing, sawung-dalêm pun Modang; (93) Lan sawungnya putranta Dyan Bèi, Wiryabrata kang abrit pun Gramang, kang samya dinadosake, Ke Kidang mèsêm muwus, si Lim Dêrma bae (m)botohi, mring jagoku si Modang, ya wus pitayèng sun, nak Dyan Bèi Wiryabrata, kêkêdhikan kewala pangajêngnèki, sapantêsing kasukan.‖ Kangjêng Gusti Pangeran Adipati Anom Amêngkunagara III (Ingkang Sinuhun Pakubuwana V), Serat Centhini (Yogyakarta: Yayasan Centhini, 1992). Dhandhanggula, canto 618, stanzas 91-93. 41 Kangjêng Gusti Pangeran Adipati Anom Amêngkunagara III (Ingkang Sinuhun Pakubuwana V), Serat Centhini (Yogyakarta: Yayasan Centhini, 1992). Dhandhanggula, canto 618, stanzas 84-85. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 41 Kangjêng Gusti Pangeran Adipati Anom Amêngkunagara III (Ingkang Sinuhun Pakubuwana V), Serat Centhini (Yogyakarta: Yayasan Centhini, 1992). Dhandhanggula, canto 618, stanzas 84-85. Cockfighting in Javanese Muslim Society Even with the noble, they did not talk to each other during the match, but they were enlivened by placing bets on the two roosters in the arena, namely Modang and Dyan Bei Wiryabrata‘s rooster, namely Gramang. I was just a little bit hopeful about having fun.‖42 The enthusiasm of cockfighting is described in the above tale by village officials and religious (Islamic) leaders. Cockfighting was one of their favorite games. They also gambled. The story in stanza 104 illustrates the value of cockfighting gambling pleasure, which influenced the subject‘s rationality. According to the story, both Jayengresmi and Jayengraga were Sunan Giri‘s descendants. Cockfighting was one of their favorite pastimes. The narration JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 372 Cockfighting in Javanese Muslim Society Cockfighting in Javanese Muslim Society Cockfighting in Javanese Muslim Society discusses the thrill of betting as long as one does not have a clear mind. It indicates that the script has discussed the harmful effects of cockfighting gambling. Someone who could explain the nature of Islam participated in botoh sawung because it was pleasant. They must have been aware of Islam‘s prohibitions on animal fighting and gambling. Despite the fact that they were aware of the law prohibiting animal fighting and gambling, they continued to hold cockfights. This story reflects the views of the Javanese Muslim society on the non-contradictory relationship between religion and tradition. They continue to follow Islamic religious practices while simultaneously engage in worldly pleasures. According to Javanese Muslims, sacred and profane demands can be satisfied in a balanced way. p In addition to Serat Centhini, Serat Pranacitra contains Javanese Muslim thoughts on botoh sawung. This manuscript was composed based on a manuscript written during Sunan Paku Buwana V in the nineteenth century. During Sunan Pakubuwana VII, this was disclosed.43 This manuscript is still contemporary with Serat Centhini even though it is set in the seventeenth century Mataram era. The original manuscript was taken from Surakarta, stored at Koninklijk Bataviaasch Genootschap van Kunsten en Wetenschappen No. 163, and spreaded by Bale Pustaka in the 1932. The story of the fighting is told in the poem Dhandhanggula Canto 1, stanzas 42-43. This section discusses about Ki Tumenggung Wiraguna, who wanted to end the fighting match because he thought about Rara Mendut, his idol girl, even though cockfighting was Ki Tumenggung Wiraguna‘s pleasure. 43 Balai Pustaka Serie No. 449, Pranacitra (Rara Mêndut): Babon Saking Surakarta (Batawi Sèntrêm: Bale Pustaka, 1932), p. 169. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 44 The original version in Javanese says: ―Ingkang andhèr nèng ngayun, pra botoh samya ambêkta sawung, myang priyayi răngga dêmang lan ngabèi, ambêkta bombonganipun, sawung ingkang wus pitados. Sampun pêpak sadarum, angandika kiyai tumênggung, mring Mas Patih Wirakăndha kinèn tandhing, patih sandika turipun, nulya undhang mring pra botoh. Lah suwawi ing ngriku, sami tinandhing bombonganipun, para botoh sandika nulya anandhing, nging dèrèng wontên kang athuk, panandhinge samya reyon. Ki tumênggung nglingnya rum, padha kapikên anandhing sawung, singa ingkang kaot wis jamaking tandhing, payo kono goprak-gapruk, mêngko gampang arêbut toh. Dèrèng pantara dangu, ingkang samya têtandhingan sawung, ya ta Pranacitra ingkang lagya prapti, kagyat sadaya kang dulu, cingak sagung para botoh.‖ Balai Pustaka Serie No. 449, Pranacitra (Rara Mêndut). JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 45 Ki Mangunprawira, Serat Adu Jago (Yogyakarta: Panti Boedaja, 1939), pp. 14-16. 46 The original version in Javanese says: ―Sawoeng ingkang dipoen gadhang badhe kaaben, poenika oemoer 9 boelan, sampoen wiwit dipoengoelawentah, dipoen sengkeri pijambak, mboten dipoen tunggilaken wonten ing kandhang ajam, sengkeran satoenggal sawoeng satoenggal.‖ Ibid., p. 24. 47 M i S Ad J 26 JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 47 Mangunprawira, Serat Adu Jago, p. 26. Cockfighting in Javanese Muslim Society The following narration proves that cockfighting was Ki Tumenggung Tirtawiguna‘s favorite. ―Those who gathered in front of the gamblers brought the roosters. Furthermore, the noble, rangga, demang, and ngabei brought their best-prided roosters. Everything was complete, Kyai Tumenggung said to Mas Patih Wirakandha to compete immediately. Patih answered. Then, he informed the gamblers. Let us go there, together to compete with their prided cock! The gamblers said to have a match soon, but nothing matched JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 373 Adi Putra Surya Wardhana, Dennys Pradita, Fiqih Aisyatul Farokhah, and Andriyanto up yet. The match was smooth. Ki Tumenggung said subtly that each cockfight is too ordinary. It is like a lion in a fight. Will they collide with each other? It is easy to win. It had not been too long; those fighting cocks, all of whom looked surprised, saw Pranacitra, who had just arrived. The gamblers were all amazed.‖44 Gambuh poem, canto 6, stanzas 3 to 125, tells about the pleasure of playing botoh sawung. The spectators placed bets on the nobles‘ fighting cocks. The story represents botoh sawung was commonly performed by Javanese aristocrats and was enjoyed by the people as an exciting spectacle. As an exciting game, cockfighting was prepared very seriously. Serat Adu Jago proves the seriousness of cockfighting. This manuscript was written by Ki Mangunprawira (Pseudonym, Ki Ajar Panitra) in 1939. Serat Adu Jago contains knowledge about the origin of cockfighting, equipment for cockfighting, selection of location for cockfighting, suitable forms of fighting cock, movements when pitted, good fighting cocks from origin, good egg selection, maintenance of fighting cock, and terms of rooster based on their age. Seriousness is shown by the construction of knowledge about the rules for producing quality fighting cocks. Owners of fighting cocks must treat them with respect, providing the highest quality food, choosing the best brooders, and determining superior eggs. Every morning, the owner must bathe and wipe the fighting cock. Every fighting cock‘s behavior must be observed; even the mating process of fighting cocks is explained by the writer of Serat Adu Jago in detail. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 374 Adi Putra Surya Wardhana, Dennys Pradita, Fiqih Aisyatul Farokhah, and Andriyanto Adi Putra Surya Wardhana, Dennys Pradita, Fiqih Aisyatul Farokhah, and Andriyanto Adi Putra Surya Wardhana, Dennys Pradita, Fiqih Aisyatul Farokhah, and Andriyanto Adi Putra Surya Wardhana, Dennys Pradita, Fiqih Aisyatul Farokhah, and Andriyanto According to Huizinga, playing is one of the human instincts, as long as it is older than culture.48 The game is not only enjoyable, but it also has a spiritual component.49 Huizinga explained some essential factors in playing both individual and communal such as contests, shows, exhibitions, challenges, preening, presenting oneself, pretending, and binding rules.50 In this case, botoh sawung is a game that allows each player to distinguish himself or their group. Every player Botoh sawung is bound by a set of rules which the gambler must follow. These rules make the game more exciting and even turn it into a place to celebrate the Javanese people‘s hedonism. 49 Stef Aupers, ―Spiritual Play: Encountering the Sacred in World of Warcraft,‖ Valerie Frissen et.al (eds), Homo Ludens 2.0: Play, Media, and Identity (Amsterdam: Amsterdam University Press, 2015), p. 75. 48 Johan Huizinga, Homo Ludens: A Study of the Play-Element in Culture (London, Boston, & Henley: Routledge & Kegan Paul Ltd, 1949), p. 1. 49 Stef Aupers, ―Spiritual Play: Encountering the Sacred in World of Warcraft,‖ Valerie Frissen et.al (eds), Homo Ludens 2.0: Play, Media, and Identity (Amsterdam: Amsterdam University Press, 2015), p. 75. 50 Huizinga, Homo Ludens: A Study of the Play-Element in Culture, p. 47. 51 Muhammad Khalid Masud, ―Shehu Usuman and Fodio‘s Restatement of the Doctrine of Hijrah,‖ Islamic Studies 25, 1 (1986), pp. 65-67. 48 Johan Huizinga, Homo Ludens: A Study of the Play-Element in Culture (London, Boston, & Henley: Routledge & Kegan Paul Ltd, 1949), p. 1. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 6 Cockfighting in Javanese Muslim Society Cockfighting in Javanese Muslim Society Cockfighting in Javanese Muslim Society Newly hatched chicks receive particular behavior from the caretaker or the owner. The rooster must be prayed for with the mantra ―lincak gagak welung bingung‖ for seven times. For the cock, the mantra recited is ―lincak gagak welung bingung‖ seven times. For the hen, the spell recited is ―Si dhendheng, si wangkeng, keng kurungkeng, dhek keng, urat kenceng, sira wangkeng, ati wanuh.‖45 g g g g The spells contain the hope that the chick can be a fighting cock and the hen can produce many superior eggs. After nine months of age, fighting cocks must be carefully cared for and separated from other roosters: ―... The rooster that will be pitted, from the age of nine months must begin to be cared for, caged alone, may not be combined in a rooster cage, each rooster must be caged individually.‖ 46 g y In the next section, the manuscript provides knowledge on caring for fighting cocks. It must be removed from time to time in order to be pleasant. If the rooster is not affected by naga kalolos (losing power), it should not commonly mate with the hen or fight with other roosters. The fighting cock is also kept for mating; thus, the rooster does not get bileng disease which causes the body to become fat and lose courage when fighting.47 Serat Adu Jago also explains the location of the cockfight, the movements of the spectators, and the amount of gambling money during the game. This manuscript states that cockfighting was a popular pastime among the nobles and commoners. The nobles constantly chewed betel during the game. The game of botoh sawung attracted people‘s attention; therefore, the cockfighting arena was always crowded. Some of them peeked between the chairs of the nobles to see botoh sawung. They enjoyed botoh sawung because humans are creatures who play games (homo ludens). JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 375 50 Huizinga, Homo Ludens: A Study of the Play-Element in Culture, p. 47. 51 Muhammad Khalid Masud, ―Shehu Usuman and Fodio‘s Restatement of the Doctrine of Hijrah,‖ Islamic Studies 25, 1 (1986), pp. 65-67. Cockfighting: Its Influence on the Rules of the Colonial and the Javanese Government Cockfighting has been a topic of debate among scholars for a long time. The prohibition of cockfighting is contained in the Hadith History of Abu Dawud and At-Tarmidhi from the companions of Ibn Abbas RA. In Islamic law, the Al-Qur‘an is the highest hierarchy. The following hierarchy is Hadith, Ijma‘, and Qiyas.51 The issue of fighting animals is not mentioned in the verses of the Al-Qur‘an. The Al-Qur‘an describes several types of lawful animals to use, consume, and ride. The Al-Qur‘an also mentions the human obligation to love animals. The obligation is interpreted as a prohibition on harming animals. What is prohibited by the Qur‘an is gambling. In Al-Ma‘idah verse 91, it is explained that gambling is an act that prevents the remembrance of Allah and prayer. Therefore, the element of gambling in cockfighting is prohibited by Islam. Nevertheless, cockfighting is still popular among Javanese Muslims. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 376 Cockfighting in Javanese Muslim Society Cockfighting in Javanese Muslim Society This reality implies that cockfighting has experienced a shift in meaning since Islam became part of the Javanese people‘s lives. Cockfighting is not practiced as a sacrificial ritual is in Islam. The Muslim community ―obediently‖ interpreted the cockfighting ritual as a legacy of the local belief system that was not under Islamic teachings during the Islamic period. Other Javanese Muslim communities interpret cockfighting as part of a tradition—those who preserve the tradition of cockfighting interpret cockfighting as a symbol of solidarity. Building solidarity is still in line with Islamic teachings. Thus, they felt they had not committed a violation. Cockfighting was also considered to have educational values by the Javanese people who preserved the game. They assumed it was an ancestral tradition that did not conflict with Islam. Throughout the nineteenth to the early twentieth centuries, the Javanese Muslim community regarded cockfighting as merely a spectacle and entertainment. At that time, cockfighting games contained elements of spectacle and entertainment that always attracted gamblers. The Javanese Muslim society often participated in cockfighting, which contained gambling, because it was more pleasant than ordinary. In addition, cockfighting became an outlet for the severe burden of life brought on by the colonial government‘ exploitation. For the nobility, cockfighting gambling was a way to forget the economic and political pressures of the colonial government. They believed that winning cockfighting bets could solve financial issues in a short time. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 53The original version in Javanese says: ―êndêming wong dhêmên ngabotohan, yèn kalah rupak jagade, sirna katrêsnaning marang anak bojone, dibalèjèdi nganti balindhis, suwe-suwe mrèmèn angapus-apusi marang sanak sadulure.‖ Ki Padmasusastra, Layang Madubasa (Surakarta: Budi Utama, 1912), p. 4. 52 Ki Padmasusastra, Sêrat Tatacara: Ngadat Sarta Kalakuwanipun Têtiyang Jawi, Ingkang Taksih Lumèngkèt Dhatêng Gugon-Tuhon (Semarang: H. A. Benyamin, 1893), p. 216. Cockfighting: Its Influence on the Rules of the Colonial and the Javanese Government Gambling cockfighting could fill the spare time of the unemployed nobles due to the intervention of colonial policies against the indigenous government. Cockfighting always draws a large crowd to watch and place bets, making prone to chaos. In the minds of the santri community, Botoh sawung undermines aqidah for Javanese Muslims. In Serat Tatacara written by Ki Padmasusastra, there is a dialogue between nobles who discusses the pleasantness of playing cockfighting. His interlocutor is a nobleman named Mandangjaplak. After returning from the Panaraga Islamic Boarding School, one of the nobles reported his son had stopped playing botoh sawung. His son became a devout worship student who read the Alquran every day and enjoyed reciting the Alquran in the langgar (prayer JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 377 Adi Putra Surya Wardhana, Dennys Pradita, Fiqih Aisyatul Farokhah, and Andriyanto room); he went Sastrajendra to study Javanese literature. As a santri, the nobleman‘s son studied nature, kodrat, and the science of falaq.52 Through this conversation, Padmasusastra wanted to message that playing botoh sawung was an evil deed. Botoh sawung was like opium, making players want to keep betting despite losing and running out of property. Padmasusastra‘s message about the negative impact of ngabotohan (gambling) was also conveyed in Serat Madubasa. He said: The drunkenness person who likes to gamble, when he has lost of control, his world is like being destroyed. He loses his love for his wife and children, his property runs out, and he likes lying to his family.53 The preceding description shows two Javanese Muslims‘ thoughts against cockfighting and botoh sawung. To begin with, cockfighting and botoh sawung are consider a tradition and a source of joy in Javanese Muslim philosophy. Second, cockfighting and botoh sawung are considered undesirable practices that are antithetical to religious teachings and self-destructive in Javanese Muslim philosophy. Cockfighting was often seen as a cause of poverty among Javanese Muslims. Therefore, the Sultanate of Yogyakarta, one of the kingdoms in Java, established regulations to regulate the gambling of animal fights, including cockfighting. According to Serat Angger Pradata Awal, Quail, and candlenut fighting were permitted at the district level and above. However, the use of spurs was prohibited by the Sultan of Yogyakarta. Serat Angger Pradata Chapter 40 explains this regulation. 54 The original version in Javanese says: ―Mungguh wong bĕbotohan. Ingkang ingsun lilani, bipati sakpandhuwur, ingkang ngadĕgake ngajago, lan angadu gĕmak. Utawa ngadu kĕmiri. Nanging iku denrĕsaa, kang bĕcik bĕcik. Mĕnawa ana wong agawe prakara, dene yen nganti ana prakara, wong tĕtukaran. Ana kang tatu utawa mati, kang amatrapana, marang wong kang ngadĕgagke kĕbotohan iku mau, sira dhĕndhaa sekĕt reyal. Dene wong kang mati utawa tatu, iku mau, yen ali warise ingkang tatu utawa mati, iku ora tarima, mulura gugate, marang pradata... Ana dene wong ngĕbotohan. Kang ura ingsun lilaniĕ, kaya ta dhadhu kĕplek, kecek, gimĕr, sakpĕpadhane, ngĕbotohan ngadu adu kang ura ingsun lilani, kayata ngadu jago tajen, ngadu jangkrik. Iku si Adipati Danurĕja, ingkang anatrapna. Wong kang ngadĕgake kĕbotohan mau, sira dhĕndhaa sĕlawe reyal. Yen nora mĕtu dhĕndhane sira gitika, kaping satus. Dene wong kang nglurug ngĕbotohan. Sira dhĕndhaa nyĕpuluh reyal. Yen nora mĕtu dhĕndhane sira gitika kaping sekĕt.‖ Sultan Hamengku Buwana, Serat Angger Pradata Awal (P.B.A 196) (Yogyakarta: Perpustakaan Museum Negeri Sanabudaya, 1865). JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 Cockfighting: Its Influence on the Rules of the Colonial and the Javanese Government ―In the case of gamble people, I allow for the regent degree and above, who hold competitions and pit quail or hazelnut. However, be careful. People fight if someone makes a case; if ―In the case of gamble people, I allow for the regent degree and above, who hold competitions and pit quail or hazelnut. However, be careful. People fight if someone makes a case; if someone is injured or dies, punish the person who made the JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 378 Cockfighting in Javanese Muslim Society gamble. Give a fine of fifty real. If the heirs do not accept it for dead or injured people, proceed with the lawsuit to the civil law... Gambling against each other, I do not allow, such as pitting roosters with spurs, pitting crickets. It was the Duke of Danureja who set the punishment. The person who founded the gamble earlier, you will be fined twenty-five real. If you don‘t get a fine, you can whip a hundred times. As for those who come to gambling, you are fined ten real each. You can whip it fifty times if you don‘t get a fine.‖ 54 The law guarantees the safety of the quail and candlenut fighting games for nobles with the regent and above rank. The consideration was that the finances of the regent and the rank of nobility above him were more secure than those of low-ranking nobles. Ordinary people were prohibited from participating in gambling because it interferes with the finances of less qualified people. Therefore, the kingdom arranged that only nobles were allowed to gamble on certain animals. If a dispute causes the victim to be injured or die, the suspect is subject to a fine. Those who do not pay the fine will be subjected to corporal punishment until they are expelled to Lodaya (forest) or Ayah (area). Gambling that was not permitted was cockfighting with spurs and the cricket fight. Violators would be fined or caned. There were types of gambling that were allowed and prohibited by the Sultan. Regarding cockfighting, Angger-angger Pradata Awal did not regulate the usual cockfighting game. That is, the law allows ordinary cockfighting and quail and candlenut fighting. 55 The original version in Javanese says: ―Bab angadêgake kalangan ngadu jago, utawa ngadu jangkrik. Ăngka 10, manawa durung kalilan ing parentah, angadêgake kalangan jago lan ngadu jangkrik, ana ing ratan utawa ing dalan gêdhe lan ing panggonan liyane kang kaambah ing ngakèh. Dene jago lan jangkrik mau padha kaanggrak katur ing parentah sarta JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 Cockfighting: Its Influence on the Rules of the Colonial and the Javanese Government The JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 379 Adi Putra Surya Wardhana, Dennys Pradita, Fiqih Aisyatul Farokhah, and Andriyanto prohibition only applied to cockfighting with spurs as a form of gambling. Taji (spurs) is a weapon made of metal that is often used in cockfighting. The use of spurs can be fatal for the rooster; it can even injure and kill the owner. In addition, the gambling game of cockfighting with spurs made gamblers fall into poverty because it is more pleasant to bet when cocks kill each other than in ordinary cockfighting. Presumably, this reality was the basis for considering the prohibition of gambling on spurred cockfighting. If the Sultanate of Yogyakarta forbade cockfighting with spurs, the Dutch East Indies colonial government forbade cockfighting held in public places without permission. In Pranatan Pulisi Tumrap Băngsa Jawi ing Indiya Nèdêrlan Chapter 2, the Dutch colonial government imposed a fine of less than sixteen rupiahs and not more than twenty-five rupiahs for committing the following offenses. ―Chapter establishing an arena for cock or cricket fighting. Number 10, if the government has not permitted it to set up cock and cricket fighting arenas on roads or major roads and in other places, many people can access them. The government threatened to kill all the roosters and crickets. Note Number 10: Since ancient times, the Javanese have enjoyed cock and cricket fighting accompanied by gambling. Moreover, the government has long ordered strict regulations to abolish gambling because it can cause poverty or misery, the regulation is stipulated in the Staatsblad of 1817, number 8, and until now, it applies as stated in the police regulation sheet in Surabaya, chapter 29, and in chapter 48, in the chapter regulation sheet for people who have regional culture located west of the Cimanok River. In the case of government efforts, this chapter of the case also includes advantages. Since the prohibition of people playing bats and crickets in their fences and houses is the same as playing cards in their homes, they cannot be categorized as government guards. Prevent people from gambling in the house only if gambling can cause damage to the peace of the country.‖55 55 The original version in Javanese says: ―Bab angadêgake kalangan ngadu jago, utawa ngadu jangkrik. banjur dipatèni kabèh. Katêrangan Ăngka 10. Wiwit ing jaman kuna băngsa Jawa iku padha karênan angadu jago lan jangkrik kalawan totohan, apamanèh paprentahan wus lawas andhawuhake pranatan kêncêng amurih sirnaning ngabotohan mau, awit bisa andadèkake kamlaratan utawa sangsara liyane, mungguh pranatan iku kapacak ing layang sêtatsêblad taun 1817 ăngka 8, lan saprene tansah katindakake kaya kang kasêbut ing layang pranataning pulisi ing Surabaya bab ping 29, lan ing bab ping 48, ing layang pranatan bab wong andarbèni kabudayan bumi kaprênah sakulone kali Cimanok. Mungguh pangudine paprentahan bab prakara iki saantara uga kalêbu kaduk. Awit ênggone anglarangi wong angadu jago lan jangkrik ana sajêroning cêpuri lan omahe dhewe pêpadhane kaya wong dolanan kêrtu ana ing sajroning omah, mula kang iku uga ora kalêbu dadi pangrêksane paprentahan. Amalangi wo ngabotohan ana sajêroning omah, kajaba yèn ênggone ngabotohan mau bisa dadi jalaran angrusakake tata têntrêming nagara. Pranatan Pulisi Tumrap Băngsa Jawi Ing Indiya Nèdêrlan (Almanak 1913, H. Buning, 1913), pp. 50–51. Available online at https://www.sastra.org/arsip-dan-sejarah/hukum-dan-pemerintahan/1736-prana- tan-pulisi-tumrap-bangsa-jawi-ing-indiya-nederlan-h-buning-1913-1509 (accessed on 14 August 2021). 56 Ruut Veenhoven ―Hedonism and Happiness ‖ Journal of Happiness Studies 4 56 Ruut Veenhoven, ―Hedonism and Happiness,‖ Journal of Happiness Studies 4 (2003), p. 437. Cockfighting: Its Influence on the Rules of the Colonial and the Javanese Government Ăngka 10, manawa durung kalilan ing parentah, angadêgake kalangan jago lan ngadu jangkrik, ana ing ratan utawa ing dalan gêdhe lan ing panggonan liyane kang kaambah ing ngakèh. Dene jago lan jangkrik mau padha kaanggrak katur ing parentah sarta JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 380 Cockfighting in Javanese Muslim Society Cockfighting in Javanese Muslim Society The regulation shows that the colonial government viewed cockfighting gambling as a game that made people miserable and contributed to poverty. The colonial government also banned the game of fighting in one‘s own home. All acts of cockfighting gambling were considered to be detrimental to the peace of the country. The contents of the regulation can be interpreted that the regulations regarding cockfighting gambling were made based on experiences. The colonial government considered and assessed that cockfighting gambling had the potential to trigger a riot. Even the colonial government used a historical approach to look at the preferences of the Javanese people that were detrimental to themselves, society, and the state since ancient times. The influence of cockfighting gambling has prompted the Javanese royal government and the colonial government to enact legal regulations. Both the Sultanate of Yogyakarta‘s government and the colonial government enacted legal restrictions to keep the country at peace. However, this regulation can be interpreted as a way to maintain the exclusivity of the cockfighting gambling game. The regulations regarding cockfighting gambling include a power dynamic, allowing only the most powerful nobles play this game. Cockfighting had become a symbol of hedonism despite the fact that it was regulated. It has a peculiarity, namely a pleasurable experience. 56 It focuses on the fulfillment of pleasure and JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 381 Adi Putra Surya Wardhana, Dennys Pradita, Fiqih Aisyatul Farokhah, and Andriyanto satisfaction.57 It is associated with the ideology and behavior of the Javanese elite. Therefore, the hedonism of the Javanese nobility was always related to power. Power is the strength or authority to influence thoughts and behavior as the wishes of the power owner.58 Power is coercive but it is not felt. The ambition to gain prestige or authority has an impact on power.59 Therefore, the actors and nobility exploited cockfighting to obtain power from the crowd. The players also desired to achieve prestige from their fellow nobles. Moreover, cockfighting symbolized masculinity and bravery for the noble who participated. 57 Masha Ksendzova et.al., ―The Portrait of a Hedonist: The Personality and Ethics behind the Value and Maladaptive Pursuit of Pleasure,‖ Personality and Individual Differences 79 (2015), pp. 68–74; Chris Heathwood, ―Desire Satisfactionism and Hedonism,‖ Philosophical Studies 128 (2006), pp. 539–63. Cockfighting: Its Influence on the Rules of the Colonial and the Javanese Government Cockfighting was used to subjugate political competitors as a sign of virility. 57 Masha Ksendzova et.al., ―The Portrait of a Hedonist: The Personality and Ethics behind the Value and Maladaptive Pursuit of Pleasure,‖ Personality and Individual Differences 79 (2015), pp. 68–74; Chris Heathwood, ―Desire Satisfactionism and Hedonism,‖ Philosophical Studies 128 (2006), pp. 539–63. 58 S.F. Marbun, ―Pemerintah Berdasarkan Otoritas dan Kekuasaan,‖ Jurnal Hukum (1996), pp. 30–34. 59 Robert Bierstedt, ―An Analysis of Social Power,‖ American Sociological Review, 15, 6 (1950), pp. 732–33. 59 Robert Bierstedt, ―An Analysis of Social Power,‖ American Sociological Review, 15, 6 (1950), pp. 732–33. 58 S.F. Marbun, ―Pemerintah Berdasarkan Otoritas dan Kekuasaan,‖ Jurnal Hukum (1996), pp. 30–34. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 Conclusion Cockfighting has been a Javanese custom since ancient times. Initially, it had a sacred value. In its development, secular values dominated. Profane values strengthened because it was followed by gambling. This change occurred in the Javanese Muslim community when the teachings of Islam forbade botoh sawung (gambling cockfighting). Cockfighting gambling is popular among the Javanese Muslim community since it is a pleasurable experience, especially when one of the roosters die. The curiosity about the toughness of the noble‘s rooster became the next pull factor. Humans, after all, have the instinct to play (homo ludens). Therefore, botoh sawung, which was prohibited by religion, has become a top- rated game among Javanese Muslims. The text Serat Centhini, Serat Pranacitra, Serat Adu Jago, and Serat Tatacara contains the views of the Javanese Muslim community on cockfighting. These texts represent the pleasures of Javanese elite nobles, as Islamic leaders, who play botoh sawung. Moreover, some JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 382 Cockfighting in Javanese Muslim Society religious leaders play botoh sawung in Serat Centhini. These stories represent botoh sawung as a symbol of prestige among the aristocratic elite. In addition, botoh sawung becomes a symbol of the owner‘s masculinity and an arena for spreading power to subdue the political opponents of the rooster owner. The winning rooster could increase the authority of the owner. On the other hand, a defeat could cause the rooster owner‘s authority to decline. However, Serat Tatacara considered that botoh sawung was a lousy game. The pleasures of Javanese Muslims playing botoh sawung influenced the legal policies of both the Javanese kingdom and the colonial government. The Sultanate of Yogyakarta made the initial angger pradata which regulates cockfighting gambling. Meanwhile, the colonial government issued prohibitions on gambling cockfighting in public and private places without permission.[] References Anderson, Wanni Wibulswasdi. ―Beyond The Cockfight: Masculinity and the Thai Dove-Cooing Contest.‖ Manusya: Journal of Humanities 8 (2005) Atlas of Mutual Heritage. ―Cockfighting in Java c. 1596.‖ https://data.collectienederland.nl/detail/foldout/void_edmr ecord/dcn_atlas-of-mutual-heritage_5093 accessed on 14 August 2021 Aupers, Stef. ―Spiritual Play: Encountering the Sacred in World of Warcraft.‖ Valerie Frissen, Sybille Lammes, Michiel de Lange, Jos de Mul, and Joost Raessens (eds). Homo Ludens 2.0: Play, Media, and Identity. Amsterdam: Amsterdam University Press, 2015. Balai Pustaka Serie No. 449. Pranacitra (Rara Mêndut): Babon Saking Surakarta. Batawi Sèntrêm: Bale Pustaka, 1932. Beatty, Andrew. Varieties of Javanese Religion: An Anthropological Account. Cambridge: Cambridge University Press, 2003. Bierstedt, Robert. ―An Analysis of Social Power.‖ American Sociological Review 15 (1950). Boogert, Jochem van den. ―Rethinking Javanese Islam Towards New Descriptions of Javanese Traditions.‖ Unpublished JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 383 Adi Putra Surya Wardhana, Dennys Pradita, Fiqih Aisyatul Farokhah, and Andriyanto Ph.D Dissertation, Universiteit Leiden, 2015. Ph.D Dissertation, Universiteit Leiden, 2015. Chakraborty, Parikshit. ―Cock Fight: The Flow of Blood.‖ The Asian Man - An International Journal 13 (2019). ----------. ―Historic Cock Fight among the Santals: An Anthropological View.‖ Social Science & Humanities International 2 (2018). ----. ―Social Impact of Cock Fight: The Study among the Santals.‖ Research Journal of Humanities and Social Sciences 9 (2018). ---------- and Falguni Chakrabarty. ―Cock Fight: A Symbolic View of Social Status.‖ International Journal of Social Science 6 (2017). ----------. ―Social-Cultural Aspects of Cock Fight: A Study among the Santals of Foringdanga, Paschim Medinipur, West Bengal, India.‖ Imperial Journal of Interdisciplinary Research 2 (2016). Christie, Jan Wisseman. Register of the Inscriptions of Java 732-1060 A.D. The Inscriptions of Mataram, 1999. Csapo, Eric. ―Deep Ambivalence: Notes on a Greek Cockfight (Part I).‖ Phoenix 47 (1993). Fauzia, Shafrina. ―Sabung Ayam di Jawa dan Bali dalam Data Prasasti.‖ Prajnaparamita Jurnal Museum Nasional (2018). Geertz, Clifford. ―Deep Play: Notes on the Balinese Cockfight.‖ Daedalus 101 (1972). Heathwood, Chris. ―Desire Satisfactionism and Hedonism.‖ Philosophical Studies 128 (2006). Hefner, Robert W. ―Where Have All the Abangan Gone? Religionization and the Decline of Nonstandard Islam in Contemporary Indonesia.‖ Michel Picard and Rémy Madinier (eds). The Politics of Religion in Indonesia: Syncretism, Orthodoxy, and Religious Contention in Java and Bali. London and New York: Routledge, 2011. Huizinga, Johan. Homo Ludens: A Study of the Play-Element in Culture. London, Boston, & Henley: Routledge & Kegan Paul Ltd, 1949. Kangjêng Gusti Pangeran Adipati Anom Amêngkunagara III (Ingkang Sinuhun Paku Buwana V). Serat Centhini. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 384 Cockfighting in Javanese Muslim Society Yogyakarta: Yayasan Centhini, 1992. Yogyakarta: Yayasan Centhini, 1992. Ki Mangunprawira. Serat Adu Jago. Yogyakarta: Panti Boedaja, 1939. Ki Padmasusastra, Layang Madubasa. Surakarta: Budi Utama, 1912. Ksendzova, Masha, Ravi Iyer, Graham Hill, Sean P Wojcik, and Ryan T Howell. ―The Portrait of a Hedonist : The Personality and Ethics behind the Value and Maladaptive Pursuit of Pleasure.‖ Personality and Individual Differences 79 (2015). Mangkudimedja, R.M. Serat Pararaton (Jakarta: Proyek Penerbitan Buku Sastra Indonesia dan Daerah, 1979), Marvin, Garry. ―The Cockfight in Andalusia, Spain: Images of the Truly Male.‖ Anthropological Quarterly 57 (1984). Masud, Muhammad Khalid. ―Shehu Usuman Dan Fodio‘s Restatement of the Doctrine of Hijrah.‖. Islamic Studies 25 (1986). Nafi‘ah, Ulfatun, Indah Wahyu Puji Utami, Wahyu Djoko Sulistyo, M Rike Andrias, Jihan Amirudin Mahmud, and Minarti. Ph.D Dissertation, Universiteit Leiden, 2015. ―Perancangan Motif Batik Dengan Inspirasi Relief Ornamentasi Candi Kidal Sebagai Pengembangan Corak Batik Desa Kidal.‖ Jurnal Praksis dan Dedikasi Sosial 1 (2018). O‘Donnell, Casey. ―On Balinese Cockfights: Deeply Extending Play.‖ Games and Culture 9 (2014). Pradita, Dennys. ―Konservasi Burung Di Indonesia Tahun 1922 Sampai 1970an: Dari Kesadaran Kultural Ke Kesadaran Lingkungan.‖ Yogyakarta: Universitas Gadjah Mada, 2020. ----------. ―Mitologi Sampai Perdagangan: Status, Peran, dan Makna Burung dalam Masyarakat Jawa dari Zaman Kolonial hingga Pradita, Dennys. ―Konservasi Burung Di Indonesia Tahun 1922 Sampai 1970an: Dari Kesadaran Kultural Ke Kesadaran Lingkungan.‖ Yogyakarta: Universitas Gadjah Mada, 2020. ----------. ―Mitologi Sampai Perdagangan: Status, Peran, dan Makna Burung dalam Masyarakat Jawa dari Zaman Kolonial hingga Milenial.‖ Pramana Yuda (ed.). Konferensi Peneliti Dan Pemerhati Burung (KPBBI ) IV Semarang. Semarang, 2018. Pradita, Dennys. ―Konservasi Burung Di Indonesia Tahun 1922 Sampai 1970an: Dari Kesadaran Kultural Ke Kesadaran Lingkungan.‖ Yogyakarta: Universitas Gadjah Mada, 2020. ----. ―Mitologi Sampai Perdagangan: Status, Peran, dan Makna Burung dalam Masyarakat Jawa dari Zaman Kolonial hingga Milenial.‖ Pramana Yuda (ed.). Konferensi Peneliti Dan Pemerhati Burung (KPBBI ) IV Semarang. Semarang, 2018. Pranatan Pulisi Tumrap Băngsa Jawi Ing Indiya Nèdêrlan (Almanak 1913, H. Buning, 1913), pp. 50–51. Available online at https://www.sastra.org/arsip-dan-sejarah/hukum-dan-pe- merintahan/1736-pranatan-pulisi-tumrap-bangsa-jawi-ing-in- diya-nederlan-h-buning-1913-1509 accessed on 14 August 2021. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 385 385 Adi Putra Surya Wardhana, Dennys Pradita, Fiqih Aisyatul Farokhah, and Andriyanto Raffles, Sophia. Memoir of the Life and Public Services of Sir Thomas Stamford Raffles. London: William Clowes and Sons, 1835. Raffles, Thomas Stamford. The History of Java. London: Black Parbury and Allen Booksellers to the Hon, 1817. Reid, Anthony. Southeast Asia in the Age of Commerce, 1450-1680 (Volume One: The Lands below the Winds). New Haven and London: Yale University Press, 1988. Ricklefs, Merle C., Mystic Synthesis in Java: A History of Islamization from the Fourteenth to the Early Nineteenth Centuries. Norwalk: EastBridge, 2006. Smith, Philip. ―The Balinese Cockfight Decoded: Reflections on Geertz, the Strong Program and Structuralism.‖ Cultural Sociology 2 (2008). Sugihartono, Ranang Agung, and Handriyotopo. Transisi: Wayang, Relief, dan Animasi. Surakarta: ISI Press, 2017. Sultan Hamengku Buwana. Serat Angger Pradata Awal (P.B.A 196). Yogyakarta: Perpustakaan Museum Negeri Sanabudaya, 1865. Suripto, Bambang Agus and Listia Pranowo. ―Relief Jenis-Jenis Fauna dan Setting Lingkungannya pada Pahatan Dinding Candi Borobudur.‖ Manusia Dan Lingkungan 8 (2001). Sykes, Naomi. ―A Social Perspective on the Introduction of Exotic Animals: The Case of the Chicken.‖ World Archaeology 44 (2012). Veenhoven, Ruut. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 Ph.D Dissertation, Universiteit Leiden, 2015. ―Hedonism and Happiness.‖ Journal of Happiness Studies 4 (2003). Walker, Samuel J. and Hanneke J.M. Meijer. ―More than Food; Evidence for Different Breeds and Cockfighting in Gallus Gallus Bones from Medieval and Post-Medieval Norway.‖ Quaternary International (2020). Woodward, Mark. Java, Indonesia, and Islam. London & New York: Springer Dordrecht Heidelberg, 2011. JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 386 JOURNAL OF INDONESIAN ISLAM Volume 15, Number 02, December 2021 386
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Selection of our books indexed in the Book Citation Index in Web of Science™ Core Collection (BKCI) Interested in publishing with us? Contact book.department@intechopen.com Numbers displayed above are based on latest data collected. For more information visit www.intechopen.com Open access books available Countries delivered to Contributors from top 500 universities International authors and editors Our authors are among the most cited scientists Downloads We are IntechOpen, the world’s leading publisher of Open Access books Built by scientists, for scientists 14% 191,000 210M TOP 1% 154 7,200 Chapter 4 Chemistry in the Operation and Maintenance of Reverse Osmosis Systems Ph.D. Robert Y. Ning Additional information is available at the end of the chapter http://dx.doi.org/10.5772/39385 http://dx.doi.org/10.5772/39385 http://dx.doi.org/10.5772/39385 © 2012 Ning; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 1. Introduction Across the spectrum of industrial and municipal water utilization and treatment plants, ex‐ tensive desalination and purification of water relies on the use of reverse osmosis (RO) membranes. Sustaining the productivity of RO plants as continuous processes for water pu‐ rification has been since the late 1970s, and still is, a significant technological challenge. The challenge is magnified on the one hand by the increasing shortages of water thus driving down the quality of available raw waters, and on the other hand by the demand and the high cost of lost production that can result from insufficient productivity of RO systems. Re‐ duced productivity of RO plants exerts serious economic impact on the downstream pro‐ duction of steam, power, microelectronics, pharmaceuticals and beverages among other products. Not only used in the front-end to provide supply of high quality process water, the loss of RO capacity to process wastewater at the back-end to allow regulated discharges can shut down production or operation of some industrial complexes. With all these re‐ quirements, efficient operation and maintenance (O&M) of RO plants based on an under‐ standing of chemistry is essential. The design and working of an RO system as a unit operation is widely described in articles, books, technical literature and design software of membrane manufacturers and updated versions of user association manuals, such as from the American Water Works Association [1] The sensitivity of RO membranes towards fouling however has presented great challeng‐ es and crises to O&M personnel [2]. Once a plant is built, changes in source water quality, inadequacies in pretreatment unit operations, and inappropriate O&M procedures lead to costly repairs to the RO. Even more serious, is the stoppage of water supply to the entire production plant of high value products. Insufficient attention to changing chemistry in raw water, and inadequate performance of pretreatment units result in our current industry © 2012 Ning; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Advancing Desalination 86 practice of expecting 2 to 4 years membrane service life along with frequent stoppages for membrane cleaning and system maintenance. When optimally controlled, RO membranes have lasted more than 12 years. Systems exist that have operated continuously, and not have to be cleaned for many years. 2. Membrane Fouling Mechanisms Feedwaters to RO systems typically are concentrated by a factor of 2 - 10 (50%-90% recov‐ ery) during production of permeate water. For simplicity in classification, three classes of fouling can be said to occur [8-11]. 1. Introduction In this article, we point to aspects of process chemistry pecu‐ liar to RO plants [3-21]. 2.1. Firstly, there is scaling The solubility limits of various dissolved salts in the concentrate stream may be exceeded, leading to deposition and growth of crystals in the flow channels and membrane surface of the RO elements. This type of fouling is referred to as scaling. Most common examples of scales are calcium carbonate, sulfates of calcium, strontium and barium, and calcium fluo‐ ride and calcium phosphate. In the examination of foulants by naked eye or with magnify‐ ing glass, crystals have well defined shapes. Inhibitors injected continuously into feedwaters to suppress crystallization are called antiscalants. For scaling to occur, seed crystals from in the super-saturated concentrate. The seed crystals may grow into discernable shapes such as plates, flakes, prisms or needles, or remain as finely dispersed particles, visible or invisible to the naked eyes. Antiscalants work by inhibiting the growth of such seed crystals, and forcing the RO concentrate to remain for a time in a supersaturated state. This mechanism is known as threshold inhibition. This task of scale growth inhibition is efficiently accomplish‐ ed by low concentrations of antiscalants maintaining high super-concentrations in the RO concentrate. The capabilities of certain antiscalants in controlling the most common scales are listed in Table 1. Such antiscalants can be used to effectively replace traditional pretreat‐ ment methods of removing the offending foulants from the raw water stream [4-7, 21]. 2.2. Secondly, there is colloidal fouling The foulants appear typically as colorless to yellow or brown soft amorphous layer during autopsy when membranes are cut and unrolled for visual examination [10]. Raw waters con‐ tain heavy loads of particles ranging from the visible kind to the smallest of the invisible. Colloidal particles can be considered here as less than 1.0 micron in size. Below 1 micron, they are invisible to the naked eye, nearly undetected by turbidity and Silt Density Index (SDI) measurements. The 0.45 micron filters used in SDI measurement do not retain colloi‐ dal particles. In fact even microfiltration and ultrafiltration pretreatment in RO systems still pass colloidal particles that result in severe colloidal fouling of the RO membranes [14,18,19]. Elemental composition analyses of washed and dried colloidal foulants for ele‐ mental carbon, hydrogen and nitrogen generally show predominance of complex microbial matter from natural sources. Inorganic components clearly discernable are clays (aluminum Chemistry in the Operation and Maintenance of Reverse Osmosis Systems http://dx.doi.org/10.5772/39385 8 87 silicate), silt (ferric-aluminium-magnesium silicates), silica (polymer represented by compo‐ sition of SiO2), and ferric and aluminum oxyhydroxides when such are used as coagulants for water clarification upstream [10, and unpublished data]. RO Foulant Traditional Pretreatment Current Capability 1. Calcium Carbonate Acidification to lower LSI, then with antiscalant to maximum LSI=2.5 Antiscalant alone: LSI=3.3;S&DSI="/4.5 2. Iron, manganese Oxidation/filtration: Greensand, manganese dioxide, catalytic oxid’n Antiscalant alone: Fe and Mn at "/ 8ppm 3. Silica: Reactive Lime, Ion-Exchange (OH) Antiscalant: "/280ppm Non-reactive None Antifoulant: variable 4. Calcium Sulfate Lime, Ion-Exchange Antiscalant: "/400x sat'n 5. Strontium Sulfate Ion-Exch ange Antiscalant: "/43x sat'n 6. Barium Sulfate Ion-Exchange Antiscalant: "/51x sat'n 7. Calcium Fluoride Lime, Ion-Exchange Antiscalant: "/16,000x sat'n 8. Colloidal Organic Matter and Sulfur UF, MF, coagulation/clarification/ MMF, slow sand and carbon filter Antifoulant alone Table 1. RO System Design Advances Made Possible by New Antiscalant and Antifoulant Chemicals. ble 1. RO System Design Advances Made Possible by New Antiscalant and Antifoulant Chemicals. Colloidal matter pre-existing in feedwater can aggregate and adhere to the membrane and brine flow channels due to increased concentration, salinity, compaction, flocculation, sur‐ face interactions and other physical and chemical factors [11, 17-19]. The colloids can be‐ come organic or inorganic or composite flocs. Dissolved ionic ferric, aluminum and calcium hydroxides and silicic acid grow to increasing particle sizes by polymerization [3,17,18]. 2.2. Secondly, there is colloidal fouling Cross-linking, and complexation of organic and inorganic polymers become gels and amor‐ phous foulants commonly seen on membranes [10,11]. Biotic debris such as polysaccharides and dead cellular matter contribute largely to this type of foulants. Through solving numer‐ ous fouling problems in existing RO plants, it has become obvious that excessive and inap‐ propriate application of pretreatment chemicals aggravate the tendency of natural colloids present in RO feedwaters to coagulate and become foulants. Anticoagulants and anti-depo‐ sition agents recently developed show promise in inhibiting this fouling process [14]. The term antifoulants then can be a term applied specifically in this particulate fouling context. 2.4. An over-riding effect Involving coagulation and deposition of colloidal particles in the RO system parallels the delta effects of large river systems. Finer and finer particles in river water that survive phys‐ ical deposition during the river’s meandering course reaches the sea. When the low salinity (low Total Dissolved Solids-TDS) river water meets the high TDS seawater, colloidal parti‐ cles coagulate and precipitate to form the river delta. This is a model of what happens in the last stages of the RO membrane system where concentrations of colloidal particles and TDS rise rapidly, and colloidal fouling takes place. 3. Antifoulant Chemical Design and Application The term antifoulant used here is in its broadest meaning covering scaling, particulate foul‐ ing and microbial fouling- the three classes of fouling mechanisms discussed above. Strat‐ egies aimed at controlling each type of fouling is summarized here. 2.3. Thirdly Biofouling is a prominent source of fouling. True of all water treatment or distribution sys‐ tems, is the growth and anchoring of microorganisms. Moderate temperatures and minimal nutrient levels in RO raw waters can support at times explosive growths of microorganisms. Bacteria capable of cell division every 20 minutes can grow from a normal count per unit vol‐ Advancing Desalination 88 ume of water to millions in the period of an 8 hours shift. Due to the tendency of bacteria to se‐ crete polymers that anchor themselves to surfaces to facilitate growth as the biofilm, this fouling mechanism is unique and poses a serious threat to the operation of RO systems. This threat is compounded by the great difficulty of treating and completely removing biofilm from the membrane surface. Associated with biofouling of proliferating nature, is the large pres‐ ence of non-proliferating organic materials secreted or deposited in natural waters. Microbes and planktons secrete into their water environment large amounts of exocellular polysacchar‐ ides in the sunlit surface waters on land and at sea, then remain in the waters as cellular de‐ bris. For RO systems maintenance, biofouling then has the two separate component of biofilm proliferation and the colloidal organic fouling by mobile colloidal particles. 3.3. Concerning prevention and management of bio-fouling In water treatment systems, the literature is extensive. Much of the art and science found useful, is applicable to RO systems as well. Several factors peculiar to the RO system can be mentioned. Chemicals used to sanitize and clean the system have to be chemically compati‐ ble with the thin, salt-rejecting, polyamide or cellulose acetate barrier membrane. Of prime concern is that accumulation and exponential growth of the microorganisms should not be allowed to occur within the system. Pretreatment of feedwater, adequate maintenance of up‐ stream unit operations, continuous flow of water through the RO unit, good monitoring and sanitization program, and used of preservatives during downtime [15] are important to this end. Normalized permeate flow and differential pressure in the system [20] are sensitive in‐ dicators of bio-fouling. 3.2. For controlling colloidal fouling The task is much more challenging due to the variety of types of potential foulants and the complexity of their interactions [3,4,8-11,13,14, 17-19], with each other in the same water, and with the membrane. Stability and agglomeration of colloidal particles is a subject of ma‐ jor importance in natural waters as well as in the treatment of process waters [14]. Drawing on the basic science of colloids, and testing of model foulants suggested by RO foulant anal‐ ysis data [10,14,19], progress is made steadily with the development of antifoulants. 3.1. For scale control The development and application of antiscalants is well known and reviewed in the field of boiling water and cooling water chemistry, and applied to boilers, evaporators, cooling tow‐ ers and cooling systems. Anionic polymers, polyphosphates and organo-phosphorous com‐ pounds, sometimes referred to as threshold inhibitors and dispersants, are used in sub- stoichiometric amounts, usually in the range of 1-5 mg/liter concentrations in RO systems. By binding to surfaces of growing crystal nuclei, the rates of crystallization from supersaturated solutions are retarded, and crystal-packing orders are modified. By this mechanism, crystalli‐ zation rates are so retarded that although super-saturation of solutes in the water will eventu‐ ally equilibrate through crystallization, within the residence time of the water in the system, there is little or no scale formation. The uniqueness of RO among water conditioning systems is that the residence time is very short (a few seconds), concentration of seed crystals is low, and temperature is constant. For this reason, higher levels of super-saturation without crystal‐ lization are possible. On the other hand, the limits of saturation and rates of scaling are hard to model, measure and predict. Interferences come from other solutes in the water, organic or inorganic. Assumptions of RO fouling limits vary considerably among practitioners. Chemistry in the Operation and Maintenance of Reverse Osmosis Systems http://dx.doi.org/10.5772/39385 89 3. Decrease of 1 to 2% in salt rejection. If a cleaning procedure fails to fully restore the system performance to the reference RO system startup values, it is certain that continued use of the same cleaning procedure will lead to accelerating decline in system performance and increasing cleaning frequency. For this reason, it is important to address two issues at this point: a) find an improved clean‐ ing procedure, b) investigate possible improvement of pretreatment to avoid membrane fouling. Continue cleaning and process improvement efforts until stability of the RO per‐ formance is attained. Even with well piloted and designed RO plants, and smooth opera‐ tions initially, source water qualities invariably change over time. Equipment and personnel changes also impact performance, requiring constant vigil and preparedness for continu‐ ous improvement of the plant. 4.1. Choosing Cleaners Major membrane manufacturers generally define five types of foulants for which various generic chemicals are recommended for blending at the site where cleaning solutions are prepared. The five types of foulants are: 1) Acid-soluble Foulants, 2) Bio-film/Bacterial Slime/Biological Matter, 3) Carbon-containing Oils/Organic Matter, 4) Dual Organic and In‐ organic Coagulated Colloids, and 5) Silica and Silicates. Proprietary booster cleaners are commercially available to fortify the effectiveness of these generic cleaners that are formu‐ lated at the site. For convenience and technical support, a large variety of proprietary RO membrane cleaners are available from chemical suppliers that specialize in RO opera‐ tions. Such proprietary cleaners and cleaning support are available when generic cleaners do not perform adequately. p q y 4.2. Cleaning Strategies 4. Membrane Cleaning Practical procedure for maintenance cleaning is limited to the re-circulation of cleaning solu‐ tions through the membrane elements. By a patented method [16] of membrane recondition‐ ing, spiral wound elements with the hard casing removed, are routinely used in selecting effective cleaners for cleaning by re-circulation. This allows for visual inspection of mem‐ brane surface after each cleaning test. It is apparent that except for easily soluble foulants like calcium carbonate, calcium phosphate or ferric and aluminum hydroxide, and less easi‐ ly dissolved foulants like silica, silicates, calcium sulfate and strontium sulfate, nearly all other RO foulants are only slightly dissolved in even the best matched cleaning solutions with extensive soaking. Removal requires high tangential flow velocities to facilitate detach‐ ment of foulants from the surfaces of the membrane and the brine-side spacer screen. Clean‐ ing is usually partially effective, especially where flow channels are clogged, and large patches within the elements are inaccessible to the re-circulating cleaning solution. For this reason, the need for cleaning should be minimized or completely eliminated by the new an‐ tiscalants and antifoulants now available, and adequate pretreatment and pilot testing of cleaning process developed during pilot testing stage. When cleaning is necessary during operation, it should be performed at the earliest stages of fouling. It is generally agreed among membrane manufacturers and practitioners that RO systems should be cleaned before the following performance changes are reached: Advancing Desalination 90 1. Loss of 10 to 15% in normalized permeate flowrate. 1. Loss of 10 to 15% in normalized permeate flowrate. 2. Increase of 10 to 15% in differential pressure. 4.2. Cleaning Strategies Experience has shown that within the same class of foulants, responses to the same cleaning solution can vary considerably. Elemental analyses of foulants and cleaning studies have shown that more than one type of foulant can be present on the membrane at the same time, requiring sequential cleaning with different cleaners. Sometimes even the order of cleaners used would make a significant difference. All this is to say that the choice of cleaners and the cleaning procedure to be used is an empirical science. For a given set of conditions in a plant, cleaning efficiencies are improved by trials over time. The progress of improvement can be greatly accelerated by conducting off-line cleaning studies on test skids for single fouled elements taken from the plant. Chemistry in the Operation and Maintenance of Reverse Osmosis Systems http://dx.doi.org/10.5772/39385 9 91 When a better cleaning method is needed in the plant, the following are the alternative strat‐ egies: Strategy 1: The plant has a history of using generic cleaning chemicals, and modest improve‐ ment in effectiveness is needed, consider purchase of proprietary booster cleaners. Strategy 2: A significant cleaning improvement is needed, look for proprietary cleaner sup‐ plier with associated cleaning expertise. Option 1: With prior knowledge of the characteris‐ tics of the foulant on hand, with consultation with the supplier, select a combination of cleaners for trial in the plant. Option 2: Send one to three fouled elements to specialist for cleaning study, foulant analysis and review of plant performance history and pretreatment process. Document the findings along with pilot cleaning results using a recommended im‐ proved cleaning procedure. Simultaneously address recovery of the plant and avoidance of repeated fouling. Option 3: Send all fouled elements for off-site cleaning by specialist. Strategy 3: All cleaning efforts by re-circulation of cleaning solutions have failed, consider non-routine methods like using proprietary membrane conditioning liquids or membrane reconstruction process by which membrane bundle is unrolled, cleaned leaf by leaf, then re‐ stored with a new hard-casing. 4.3. On-line Cleaning Procedure Basically there are six (6) steps in the cleaning of membrane elements in place in RO sys‐ tems: 1. Mix Cleaning Solution. 2. Low Flow Pumping. Pump preheated cleaning solution to the vessels at conditions of low flow rate (about half of that shown in Table 2) and low pressure to displace the process wa‐ ter. With the RO concentrate throttling valve completely open to minimize pressure during cleaning, use only enough pressure to compensate for the pressure drop from feed to con‐ centrate. The pressure should be low enough that essentially no permeate is produced. A low pressure minimizes re-deposition of dirt on the membrane. Dump the concentrate, as necessary, to prevent the dilution of the cleaning solution. 3. Re-circulate. After the process water is displaced, cleaning solution will be present in the concentrate stream. Re-circulate the concentrate to the cleaning solution tank and allow the temperature to stabilize. 4. Soak. Turn the pump off and allow the elements to soak. Sometimes a soaking period of about 1 hour is sufficient. For difficult to clean foulants, an extended overnight soaking peri‐ od of 10-15 hours is beneficial. To maintain a high temperature during an extended soaking period, use a slow re-circulation rate (about 10% of that shown in Table 2). 5. High Flow Pumping. Feed the cleaning solution at the rates shown in Table 2 for 30-60 minutes. The high cross-flow rate flushes out the foulants removed from the membrane sur‐ face by the cleaning, with minimal or no permeation through the membrane to avoid com‐ pacting the foulant. If the elements are heavily fouled (which should not be a normal Advancing Desalination 92 occurence), a flow rate which is 50% higher than shown in Table 1 may aid cleaning. At higher flow rates excessive pressure drop may be a problem. The maximum recommended pressure drop is 20 psi per element or 60 psi per multi-element vessel, whichever value is more limiting. Note: In this cleaning mode, foulants are generally partially dissolved in the cleaner and par‐ tially dislodged physically from the membrane and flow channels without dissolving. An in-line filter removes the re-circulated particles, and should be monitored for cartridge re‐ placement. 6. Flush Out. Pre-filtered raw water can be used for flushing out the cleaning solution, un‐ less there will be corrosion problems such as with seawater corroding stainless steel piping. Multi Stage Systems For tapered multi-staged systems the flushing and soaking steps can be performed simulta‐ neously in the entire array. The high flow-rate re-circulation step however should be carried out separately for each stage, so that the flow-rate is not too low in the first stage and too high in the last. This can be accomplished either by using one cleaning pump and operating one stage at a time, or using a separate cleaning pump for each stage. 4.3. On-line Cleaning Procedure To prevent precipitation, the minimum flush temperature is 20 deg. C. Additional Notes: The pH should be monitored during acid cleaning. The acid is consumed when it dissolves alkaline scales. If the pH increases more than 0.5 pH units, add more acid. Feed Pressure* Element Diameter Feed Flow Rate (psig) (inches) Per Vessel (GPM) 20 - 60 2.5 3 - 5 20 - 60 4 8 -10 20 - 60 6 16 -20 20 - 60 8 30 -40 * Dependent on the number of elements in the pressure vessel Table 2. Recommended High Re-circulation Flow Rates During Cleaning. Table 2. Recommended High Re-circulation Flow Rates During Cleaning. 4.4. Control and Improvement of Cleaning Process To assure complete recovery of membrane performance by cleaning, the system perform‐ ance should be adequately controlled by trending of normalized flux, differential pres‐ sure and salt rejection [20] to 1) trigger a cleaning when any monitored parameters change from normal baseline by 10-15%, 2) record the trended parameters before and after each cleaning, 3) initiate improvement actions for better cleaning if membrane performance does Chemistry in the Operation and Maintenance of Reverse Osmosis Systems http://dx.doi.org/10.5772/39385 93 not fully recover. A change in responsiveness to previously effective cleaning process sig‐ nals a change in fouling pattern that requires immediate attention. If partial cleanings are allowed to continue, the system performance will decline at increasing rate, and will be‐ come increasingly difficult to recover. In-place cleaning processes are improved primarily by the choice of cleaning chemicals and the order of the application sequence. Depending on the composition of the complex fou‐ lants, when two or more cleaners are found necessary, often the order in which they are used is important. Also critical, but to lesser extents are the variables of time, tempera‐ ture, and cross-flow rate. Through thorough review of the water and pretreatment chemistry, analyses of the fou‐ lant composition and source, and customized selection of antiscalants, dispersants and high performance cleaners, both fouling avoidance and reliable plant performance can be at‐ tained. Practical experiences show that plant performances invariably change over years of service due to imposed changes in source water, equipment, regulatory and human fac‐ tors. Attentive operation and maintenance assures early detection of developing problem, and timely adjustments. 5. Conclusion High rejection of dissolved salts and suspended colloidal particles in RO feedwater cause scaling and colloidal fouling of membranes. Understanding the chemistry of membrane fouling and methods of control, coupled with keen monitoring during O&M, are necessary for the assurance of RO process stability. Ever increasing need for maximum water extrac‐ tion, while reducing the volume of concentrate requiring disposal pose challenges to chemi‐ cal understanding and control by O&M personnel. Information provided in this chapter provide key words and concepts for the readers to glean from the expansive literature. For readers who assume responsibilities of existing RO plants, problems may have arisen due to inadequate pretreatment design, or due to changed sources of raw water. A compan‐ ion chapter on pretreatment for reverse osmosis systems is available on line in an open-ac‐ cess book on Desalination [22]. Author details Ph.D. Robert Y. Ning* Address all correspondence to: Rning@kingleetech.com Address all correspondence to: Rning@kingleetech.com King Lee Technologies, San Diego, California, United States of America King Lee Technologies, San Diego, California, United States of America Advancing Desalination 94 References [1] Bergman, R. Ed (2007). Reverse Osmosis and Nanofiltration. , Manual M46, 2nd Edn., American Water Works Association, Denver, CO. [2] Paul, D. H. (2003). The Four Most Common Problems in Membrane Water Treatment Today, Analyst, Winter, 1-5; and world-wide training seminars of D.H. Paul, Inc. [3] Ning, R. Y. (2003). Discussion of Silica Speciation, Fouling, Control and Maximum Reduction. Desalination, 151, 67-73. [4] Ning, R. Y., Troyer, T. L., & Tominello, R. S. (2009). Antiscalants for Near Complete Recovery of Water with Tandem RO Process. Desalination and Water Treatment, 9, 92-95. [5] Ning, R. Y., & Netwig, J. P. (2002). Complete Elimination of Acid Injection in Reverse Osmosis Plants. Desalination, 143, 29-34. [6] Ning, R. Y. (2001, September). Antiscalants That Permit Operation of RO Systems at High pH Levels. Ultrapure Water, 18-21. [7] Ning, R. Y. (2000, September). Making an Ideal Process for Pure Water by Reverse Osmosis. Water Conditioning & Purification. [8] Ning, R. Y. (1999, April). Operational Characteristics of Reverse Osmosis Process Chemistry. Ultrapure Water, 39-42. [9] Ning, R. Y. (1999). Reverse Osmosis Process Chemistry Relevant to the Gulf. Desali‐ nation, 123, 157-164. [10] Ning, R. Y., & Shen, P. T. L. (1998, April). Observations from Analysis of Reverse Os‐ mosis Membrane Foulants. Ultrapure Water, 37-40. [11] Ning, R. Y., & Stith, D. (1997, March). The Iron, Silica and Organic Polymer Triangle. Ultrapure Water, 30-32. [12] Ning, R. Y. (2003). A Paradigm Shift from Prepurification of Membrane Feedstreams to Minimal Chemical Intervention. Amer. Membr.Tech. Assoc. 2003 Annual Symposium, Westminster, CO, August 3-5. [13] Ning, R. Y. (2003). Sustaining the Production of Pure Water in Reverse Osmosis Plants for First Use or Reuse. Annual Water Technologies Convention, Amer. Water Tech‐ nologists, Phoenix, AZ, September 17-20. [14] Ning, R. Y., Troyer, T. L., & Tominello, R. S. (2003). Chemical Control of Colloidal Fouling of Reverse Osmosis Systems. World Congress on Desalination and Water Re‐ use, Intern. Desal. Assoc., Bahamas, Sept. 28-Oct.3; Desalination, 172, 1-6 (2005). [15] Varnava, W., Silbernagel, M., Kuepper, T., & Miller, M. (1996, August). Reverse Os‐ mosis Element Preservation Study. Proceedings of Biennial Conf., Amer. Desalting As‐ soc., 308-327. Chemistry in the Operation and Maintenance of Reverse Osmosis Systems http://dx.doi.org/10.5772/39385 9 Chemistry in the Operation and Maintenance of Reverse Osmosis Systems http://dx.doi.org/10.5772/39385 9 95 [16] Netwig, C. L., & Kronmiller, D. L. (1993). U.S. Patent No. 5,250,118. [17] Ning, R. Y. (2010). References Reactive Silica in Natural Waters- A Review. Desalination and Wa‐ ter Treatment, 21, 79-86. [18] Ning, R. Y. (2009). Colloidal Iron and Manganese in Water Affecting RO Operation. Desalination and Water Treatment, 12, 162-168. [19] Ning, R. Y., & Troyer, T. L. (2007). Colloidal Fouling of RO Membranes following MF/UF in the Reclamation of Municipal Wastewater. Desalination, 208, 232-237. [20] Troyer, T. L., Tominello, R. S., & Ning, R. Y. (2006, September). A Method to Auto‐ mate Normalization and Trending for RO Plant Operators. Ultrapure Water, 37-43. [21] Ning, R. Y. (2003, September). Process Simplification Through the Use of Antisca‐ lants and Antifoulants. Ultrapure Water, 17-20. [22] Ning, R. Y. (2011). Pretreatment for Reverse Osmosis Systems, in Expanding Issues in Desalination, Ning, R.Y., Editor, InTech Open Access Book. Available: http:// www.intechopen.com/articles/show/title/pretreatment-for-reverse-osmosis-systems.
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y ( , ) 3 Statistics New Zealand New Zealand in profile: An overview of New Zealand's people, economy and environment (Statistics New Zealand, February 2014) at 3. y 4 Kyleisha Foote & Mike Joy "The true cost of milk: Environmental deterioration vs. profit in the New Zealand dairy industry" (paper presented at the 2014 New Zealand Agricultural & Resource Economics Society (Inc.), Nelson, August 2014). 1 Ministry for the Environment Valuing Our Clean Green Image (Ministry for the Environment, August 2001). 2 Tim Herzog, Jonathan Pershing, and Kevin A. Baumert Navigating the Numbers: Greenhouse Gas Data and International Climate Policy (World Resources Institute, 2005) at 22. LOTTIE BOARDMAN Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? , g ) 5 Alastair Cameron "New Zealand Emissions Trading Scheme" in Alastair Cameron (ed) Climate Change Law and Policy in New Zealand (LexisNexis NZ Ltd, Wellington, 2011) 239 at 244 – 245. 9 Office of the Minister for Climate Change Issues "Emissions Trading Scheme Review 2012 – final dec on amendments to the Climate Change Response Act 2002". y g 6 Ministry for the Environment "United Nations Framework Convention on Climate Change" www.mfe 7 ONE News "John Key defends Kyoto decision" (12 November 2012 ) http://tvnz.co.nz. y g g ( y , g 2 Tim Herzog, Jonathan Pershing, and Kevin A. Baumert Navigating the Numbers: Greenhouse Gas International Climate Policy (World Resources Institute, 2005) at 22. 8 "The Climate Change Response (2050 Emissions Target) Notice 2011" (31 March 2011) 41 New Zealand Gazette 987. g p 10 Jessika Luth Richter and Lizzie Chambers "Reflections and Outlook for the New Zealand ETS: must uncertain times mean uncertain measures?" (2014) 10 Policy Quarterly 57 at 63. y g g y g 2 Tim Herzog, Jonathan Pershing, and Kevin A. Baumert Navigating the Numbers: Greenhouse Gas Data and International Climate Policy (World Resources Institute, 2005) at 22. 3 Statistics New Zealand New Zealand in profile: An overview of New Zealand's people, economy and environment (Statistics New Zealand, February 2014) at 3. 4 Kyleisha Foote & Mike Joy "The true cost of milk: Environmental deterioration vs. profit in the New Zealand dairy industry" (paper presented at the 2014 New Zealand Agricultural & Resource Economics Society (Inc.), Nelson, August 2014). 5 Alastair Cameron "New Zealand Emissions Trading Scheme" in Alastair Cameron (ed) Climate Change Law and Policy in New Zealand (LexisNexis NZ Ltd, Wellington, 2011) 239 at 244 – 245. 6 Ministry for the Environment "United Nations Framework Convention on Climate Change" www.mfe.govt.nz. 7 ONE News "John Key defends Kyoto decision" (12 November 2012 ) http://tvnz.co.nz. 8 "The Climate Change Response (2050 Emissions Target) Notice 2011" (31 March 2011) 41 New Zealand Gazette 987. 9 Office of the Minister for Climate Change Issues "Emissions Trading Scheme Review 2012 – final decisions on amendments to the Climate Change Response Act 2002". 10 Jessika Luth Richter and Lizzie Chambers "Reflections and Outlook for the New Zealand ETS: must uncertain times mean uncertain measures?" (2014) 10 Policy Quarterly 57 at 63. 11 Jonathan Boston and Frieder Lempp "Climate change: Explaining and solving the mismatch between scientific inertia and political inertia" (2011) 24 AAAJ 1001 at 1002. 12 ( ) y Q y 11 Jonathan Boston and Frieder Lempp "Climate change: Explaining and solving the mismatch between scientific inertia and political inertia" (2011) 24 AAAJ 1001 at 1002. 12 At 1006. Ministry for the Environment Valuing Our Clean Green Image (Ministry for the Environment, August 200 on amendments to the Climate Change Response Act 2002 . 10 Jessika Luth Richter and Lizzie Chambers "Reflections and Outlook for the New Zealand ETS: must uncertain times mean uncertain measures?" (2014) 10 Policy Quarterly 57 at 63. 11 Jonathan Boston and Frieder Lempp "Climate change: Explaining and solving the mismatch between I. Introduction New Zealand and New Zealanders have a complex and somewhat contradictory relationship with the natural environment. While New Zealanders enjoy their country's significant natural beauty and profit from its “clean, green” image,1 New Zealand’s per capita greenhouse gas (“GHG”) emissions are near to twice those of the United Kingdom2 and the environmental cost of dairying (New Zealand’s highest export earner)3 arguably exceeds the profit made from it.4 It is in this context that New Zealand's primary action on climate change is an emissions trading scheme ("ETS") for GHGs that does not include half of its emissions (those that come from agriculture) and would be counted as successful if it reduced emissions only minimally.5 New Zealand did not commit to the second commitment period under the Kyoto Protocol6 and yet the current National government continues to maintain the stance that New Zealand should be a “fast follower” when it comes to climate change action.7 The National government has set the goal of reducing carbon emissions by 50% by 20508 and has said that it seeks to encourage a smooth transition to a low-carbon economy.9 While it could be argued that current policies are not encouraging this transition at all,10 it is an understandable goal given the significant changes that need to take place. Short of strengthening the ETS, an initiative that could assist in this transition would be requiring companies to take into account their environmental impact and (at least for listed companies) to report on their environmental impacts. Disclosure of environmental impact information by companies would be an important step in transitioning to a low-carbon and otherwise environmentally- sustainable economy and society. To do anything about the problems that humanity faces, the environmental impacts of business must be understood. This accounting asymmetry is one of four political asymmetries that Boston and Lempp identify as being influential in the inability of democracies to take action on climate change.11 As they quote:12 1 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? What we measure affects what we do; and if our measurements are flawed, decisions may be distorted. cl 7.4; Corporations Act 2001 (Cth), s299(1)(f). 15 Sarbanes-Oxley Act of 2002, Pub. L. No. 107-204, 116 Stat. 745. y 16 Companies listed on a relevant stock exchange. p ( ) X Corporate Governance Council Corporate Governance Principles and Recommendations (3rd ed, 2014) ; Corporations Act 2001 (Cth), s299(1)(f). 13 Companies Act 2006 (UK), s 414C. ASX Corporate Governance Council Corpora cl 7.4; Corporations Act 2001 (Cth), s299(1)(f). y , , 16 Companies listed on a relevant stock exchange. y anies listed on a relevant stock exchange. Companies Act 2006 (UK), s 414C. 14 ASX Corporate Governance Council Corporate Governance Principles and Recommendations (3rd ed, 2014), cl 7.4; Corporations Act 2001 (Cth), s299(1)(f). 15 Sarbanes O le Act of 2002 P b L No 107 204 116 Stat 745 mpanies Act 2006 (UK), s 414C. X Corporate Governance Council Corporate Governance Principles and Recommendations (3rd ed, 2014) I. Introduction Choices between promoting GDP and protecting the environment may be false choices, once environmental degradation is appropriately included in our measurement of economic performance One reason why climate change action is not taken is because current systems are set up to measure financial cost, without taking into account the environmental costs of particular courses of action. As these costs are better understood, the case for climate change (or other environmental) action becomes much stronger. Corporate environmental disclosure and corporate consideration of the environment when making decisions are areas where New Zealand has not been a “fast follower”. New Zealand is not the only country which lacks mandatory corporate environmental reporting; however, other common law countries including the United Kingdom,13 Australia,14 and the United States of America15 all have some form of mandatory corporate environmental reporting, at least in respect of listed companies.16 This paper addresses whether New Zealand should introduce a requirement for company directors to consider the environment when making decisions, and, at least for listed companies, require companies to report on their environmental impact. The first section of the paper (Parts II – V) will examine the current relationship between New Zealand companies and the environment, by addressing: (a) law relating to company decision-making, reporting and disclosure, with a particular focus on companies listed with the NZX (Part II); (b) global environmental problems arising from a “business-as-usual” approach (Part III); (c) responses to these environmental challenges in New Zealand’s environmental law and the opportunities for corporate discretion (Part IV); and (d) voluntary responses of New Zealand companies to these issues (Part V). The paper will then consider whether New Zealand should incorporate environmental considerations and environmental reporting into company law. Part VI will discuss the rationale and justification for requiring corporate consideration of the environment and for corporate environmental reporting. Part sVII - IX will critically analyse three options for influencing corporate decision making in relation to the environment and encouraging corporate environmental reporting. Part VII will consider the United Nations Global Compact ("UNGC") and compare it to existing voluntary environmental initiatives in New Zealand. Part VII will also discuss the efficacy of mandatory environmental reporting. Part 2 2 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? VIII will analyse the "enlightened shareholder value" provisions in the UK Companies Act 2006 and associated regulation. II. The decision-making and disclosure obligations of New Zealand companies Not surprisingly, the most important piece of legislation relating to companies in New Zealand is the eponymous Companies Act 1993 ("CA" or "NZ Act"). The CA is the primary source of rules for companies from incorporation through to liquidation. The vast majority of companies incorporated under the CA are limited liability companies; 17 "owners" of the company own shares in it. The shareholders have no direct claim on company assets as the assets are owned by a separate legal person, the company.18 The CA provides that the company will be managed by or under the supervision of a board of directors19 who will be elected or appointed by the shareholders of the company.20 The board can delegate the on- the-ground running of the company to a chief executive officer and other employees if they so wish.21 However the overall responsibility for the company's actions lies at the feet of the directors.22 At s 130(2). 23 Peter Watts Directors' Powers and Duties (LexisNexis, Wellington, 2009) at 125. 24 Companies Act 1993, s 131. A. Directors' duties A. Directors' duties The CA sets out a number of duties that the directors owe, some to the company and some to shareholders. Many of the duties owed to the company are codified derivations of common law and equitable duties.23 17 Companies Office "Legislation" www.business.govt.nz. 18 18 Companies Act 1993, s 15. 19 I. Introduction Part IX will assess a suggested directors’ duty requiring companies to interact with the environment in a sustainable way. Part X will discuss all three options and conclude the paper. II. The decision-making and disclosure obligations of New Zealand companies II. The decision-making and disclosure obligations of New Zealand companies 22 At s 130(2). At s 36. 21 At s 130(1). 22 At s 130(2). 20 At s 36. 21 At s 130(1). p 19 At s 128. Directors owe positive duties to the company to: Directors owe positive duties to the company to: (a) "act in good faith and in what the director believes to be the best interests of the company";24 (a) "act in good faith and in what the director believes to be the best interests of the company";24 (b) exercise their powers for a proper purpose;25 and (c) act with "the care, diligence, and skill that a reasonable director would in the same circumstances".26 On the other hand, directors owe duties to the company not to: 26 At s 137. 3 3 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? a) agree to or cause or allow the business of the company to be carried on in a manne likely to create a substantial risk of serious loss to the company's creditors;27 and y p y ; (b) agree to the company incurring an obligation, unless the director believes at the time on reasonable grounds that the company will be able to perform the obligation when it is required to do so.28 The duties are broadly drawn with case law filling in some of the picture. However, there is a broad discretion left to directors and the courts will usually defer to the judgment of directors where decisions are taken in good faith.29 A director's primary duty is to act in the best interests of the company.30 This is usually interpreted to mean "in the best interests of the shareholders as a whole".31 The best interests of the shareholders as a whole are presumed to be (unless the constitution says otherwise) to maximise the profits of the company.32 Where the company is insolvent or close to insolvent, the best interests of the company cease to be completely identified with the interests of the shareholders – at that point, the interests of the creditors must be considered.33 There is debate as to whether the best interests of the shareholders as a whole should be interpreted as the best interests of the present shareholders or the best interests of both present and future shareholders – effectively whether the directors should take a short or long term view as to the life of the company. As shown by investor initiatives such as the Coalition for Environmentally Responsible Economies and th arbon Disclosure Project. 27 At s 135. 28 At s 136. 29 See for instance Nicholson v Permakraft (NZ) Ltd [1985] 1 NZLR 242 per Cooke P (CA). 30 Watts, above n 23, at 143. 31 At 129. 32 At 147. 33 At 130. 34 Jonathan Boston "The Nature of the Problem and the Implications for New Zealand" in Alastair Cameron (ed) Climate Change Law and Policy in New Zealand (LexisNexis NZ Ltd, Wellington, 2011) 87 at 91. 35 As shown by investor initiatives such as the Coalition for Environmentally Responsible Economies and the Carbon Disclosure Project. At 130. 34 Jonathan Boston "The Nature of the Problem and the Implications for New Zealand" in Alastair Cameron (ed) Climate Change Law and Policy in New Zealand (LexisNexis NZ Ltd, Wellington, 2011) 87 at 91. 35 As shown by investor initiatives such as the Coalition for Environmentally Responsible Economies and the Carbon Disclosure Project. At s 136. 29 See for instance Nicholson v Permakraft (NZ) Ltd [1985] 1 NZLR 242 per Cooke P (CA). 30 Watts, above n 23, at 143. 31 Directors owe positive duties to the company to: This choice leads to different profit-maximising strategies - for example maximising increases in the value of shares in the short-term or maximising the long-term value of the company which may mean sacrifices in the short term. This has implications for the directors’ attitudes towards the environment – it may well maximise short term profits to damage the environment whereas it may be in the long-term interests of the company and society to conserve the natural environment.34 The profit-maximisation strategy is a discretionary decision by the directors and as long as they act in good faith, it is unlikely that they would face any sanction. Of course, if the shareholders are unhappy with the strategy the director is taking, they have the power to remove the directors and appoint new ones in their place. However, given changing attitudes of society and institutional investors, 35 it seems unlikely that directors would be removed for seeking to be environmentally responsible, provided the company is making some profit. - for example maximising increases in the value of shares in the short-term or maximising the long-term value of the company which may mean sacrifices in the short term. This has implications for the directors’ attitudes towards the environment – it may well maximise short term profits to damage the environment whereas it may be in the long-term interests of the company and society to conserve the natural environment.34 The profit-maximisation strategy is a discretionary decision by the directors and as long as they act in good faith, it is unlikely that they would face any sanction. Of course, if the shareholders are unhappy with the strategy the director is taking, they have the power to remove the directors and appoint new ones in their place. However, given changing attitudes of society and institutional investors, 35 it seems unlikely that directors would be removed for seeking to be environmentally responsible, provided the company is making some profit. 4 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? The environment does not currently feature in the directors duties. Arguably, the directors could take into account the interests of the environment (as they can in Canada)36 provided they still act in the best interests of the company. B. Enforcement of directors' duties to the company 36 Peoples Department Stores Inc. (Trustee of) v Wise [2004] 3 SCR 461. 37 Companies Act 1993, s373(4). 36 Peoples Department Stores Inc. (Trustee of) v Wise [2004] 3 SCR 461. 37 Companies Act 1993, s373(4). 38 At s 138A. 39 Brookers Company Law (online looseleaf ed, Thomson Reuters) at [CA373.03]. 40 Companies Act 1993, s 169. 41 At s 165. 42 At s 165(1). 43 At s 165(2). 44 At s 166. 45 See s 36(c) – shareholders have a right to shares in the distribution of the surplus assets of the company. 46 At s 164. 47 At s 260 and Schedule 6. At s 166. 45 See s 36(c) – shareholders have a right to shares in the distribution of the surplus assets of the company. 46 At s 164. 47 At s 260 and Schedule 6. 39 Brookers Company Law (online looseleaf ed, Thomson Reuters) at [CA373.03]. 40 Companies Act 1993 s 169 At s 138A. 39 Brookers Company Law (online looseleaf ed, Thomson Reuters) at [CA373.03]. At s 138A. 39 Brookers Company Law (online looseleaf ed Thomson Reuters) at [CA373 03] 37 Companies Act 1993, s373(4). 38 At s 138A. 39 Brookers Company Law (online looseleaf ed Thomson Reuters) at [CA373 B. Enforcement of directors' duties to the company It is an offence punishable by up to five years’ imprisonment or a fine of up to $200,000.0037 for a director to exercise powers or perform duties as a director in bad faith, believing the conduct not to be in the best interests of the company and knowing that the conduct will cause serious loss to the company.38 Charges under this section would be brought by the police.39 In terms of civil enforcement, shareholders can directly enforce duties that the directors owe to them.40 However, as outlined above, many of the important duties are not owed to shareholders but to the company itself. The only way that a shareholder can bring an action on behalf of the company against a director is by way of a derivative action.41 The shareholder requires the Court's leave to bring a derivative action. 42 When considering whether to allow the derivative action to proceed, the Court shall have regard to the likelihood of the claim succeeding, the cost of the proceedings in relation to the relief likely to be obtained and the interests of the company in the proceedings being commenced.43 The costs of the proceeding, once leave is granted, will be paid for by the company, unless it would be unjust or inequitable for it to do so.44 However, there is little incentive for a shareholder to bring a derivative action against a director retrospectively. Any recovery that was made would go to the company, to pay off creditors and finally shareholders in a liquidation situation.45 The CA also contains provisions allowing the company, a shareholder or director or an entitled person to apply for an injunction to prevent the directors or the company from taking an action that is contrary to the company’s constitution or is in breach of the CA.46 If a shareholder or a director knows beforehand about a potential breach of the directors’ duties to the company, they could apply for an interim or permanent injunction to prevent the breach from occurring. The liquidators of a company are empowered to take an action on the company’s behalf,47 and may have more of an incentive than shareholders to take an action against directors if it 43 At s 165(2). 5 5 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? B. Enforcement of directors' duties to the company would result in a greater recovery for creditors (and for the liquidators themselves in the payment of their fees).48 At s 197. 53 See Financial Markets Conduct Act 2013, s 451 (definition of reporting entities) and s 6 (definitions of listed issuer). 54 Financial Markets Conduct Act 2013, s 460. p 50 See s 198, which refers to the definition in s 45 of the Financial Reporting Act 2013. 51 At s 207 48 Under cl 1 of Schedule 7 of the Companies Act, the fees and expenses of the liquidator are the highest priority. p y 49 Companies Act 1993, s 201. Companies Act 1993, s 201. See s 198, which refers to the definition in s 45 of the Financial Reporting Act 2013. At 207 49 Companies Act 1993, s 201. 48 Under cl 1 of Schedule 7 of the Companies Act, the fees and expenses of the liquidator are the highest priority. 49 Companies Act 1993, s 201. 50 See s 198, which refers to the definition in s 45 of the Financial Reporting Act 2013. 51 At s 207. 52 At s 197. 53 See Financial Markets Conduct Act 2013, s 451 (definition of reporting entities) and s 6 (definitions of listed issuer). 54 Financial Markets Conduct Act 2013, s 460. 55 At s 461D. 50 See s 198, which refers to the definition in s 45 of the Financial Reporting Act 2013. 51 At s 207. 52 At s 197 C. Financial reporting obligations Act 2013 (“FRA”). 56 “Financial statements” must comply with the applicable financial reporting standards. 57 These standards are produced by the External Reporting Board (“XRB”) set up under subpart 1 of part 2 of the FRA. Under the FRA, there are four tiers of reporting obligations. The most stringent are Tier 1 obligations; these apply to entities that are "socially accountable" (including listed issuers)58 and to large entities.59 Therefore the actual standards that listed issuers (covered by the FMCA) and large companies (covered by the CA) must meet will usually be the same. Act 2013 (“FRA”). 56 “Financial statements” must comply with the applicable financial reporting standards. 57 These standards are produced by the External Reporting Board (“XRB”) set up under subpart 1 of part 2 of the FRA. Under the FRA, there are four tiers of reporting obligations. The most stringent are Tier 1 obligations; these apply to entities that are "socially accountable" (including listed issuers)58 and to large entities.59 Therefore the actual standards that listed issuers (covered by the FMCA) and large companies (covered by the CA) must meet will usually be the same. Importantly, the XRB can be empowered60 to produce financial reporting standards that relate to:61 (i) an entity’s governance: (ii) an entity’s strategic direction and targets: (iii) the social, environmental, and economic context in which an entity operates: (iv) any other matter relating to an entity’s performance or position As yet, the XRB has not been empowered to do so. If such standards were produced, then companies in the defined categories would have to apply them. As yet, the XRB has not been empowered to do so. If such standards were produced, then companies in the defined categories would have to apply them. As yet, the XRB has not been empowered to do so. If such standards were produced, then companies in the defined categories would have to apply them. 56 Financial Reporting Act 2013, s 2(1). 57, At s 6. 58 Standard XRB A1, at paras 12 – 13. The definition of large here is slightly different – the entity must have expenses of over $30 million. 59 Standard XRB A1, at para 17– 18. 60 By the Governor-General by Order in Council on the recommendation of the Minister responsible for the FRA. 61 Financial Reporting Act 2013, s 17. 62 Unless they opt out for that accounting period under s 207I. 63 At s 208. 64 At s 211. 65 At s 207K. E. Disclosure under the NZX Listing Rules 56 Financial Reporting Act 2013, s 2(1). p g 62 Unless they opt out for that accounting period under s 207I. 63 At 208 C. Financial reporting obligations Directors have duties to disclose information about the company’s activities to allow shareholders to assess a director's performance as their (or rather the company’s) agent. As described above, directors have significant discretion as to the running of the company. The primary power of shareholders in relation to directors is the power to elect and remove directors. Alternatively, the shareholders can seek to sell their shares if they are not happy with the company’s performance. To make those decisions, shareholders have to know what directors are doing with shareholders’ money – directors have to be accountable. The need for accountability underlies the legislative requirements detailed below for companies to prepare financial statements in accordance with set standards. Having set standards with penalties in place for breaches minimises the likelihood of or the incentive to report financial information or results in a way favourable to the company and hence to the directors maintaining their position. The CA requires large companies, large overseas companies, companies that are public entities and companies with more than 10 shareholders to prepare financial statements in accordance with generally accepted accounting practice.49 Large companies are companies that have total assets (including the assets of subsidiaries) of more than $60 million or total revenue (including the revenue of subsidiaries) of over $30 million. 50 The financial statements prepared must be audited by a qualified auditor, unless an exception applies.51 Companies that are reporting entities under the Financial Markets Conduct Act 2013 ("FMCA") are exempt from the CA's financial reporting regime and must instead comply with the FMCA reporting regime.52 Companies listed on the NZX are reporting entities under the FMCA.53 Like large companies, FMC reporting entities must prepare financial statements in accordance with generally accepted accounting practice.54 Again, the financial statements must be audited by a qualified auditor.55 Both the CA and the FMCA define “financial statements” and “generally accepted accounting practice” with reference to the definitions contained in the Financial Reporting 48 Under cl 1 of Schedule 7 of the Companies Act, the fees and expenses of the liquidator are the highest priority At s 197. 53 See Financial Markets Conduct Act 2013, s 451 (definition of reporting entities) and s 6 (definitions of listed issuer). 54 Financial Markets Conduct Act 2013, s 460. 55 At s 461D 6 6 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? 60 By the Governor-General by Order in Council on the recommendation of the Minister responsible for FRA. 61 Financial Reporting Act 2013 s 17 61 Financial Reporting Act 2013, s 17. p g 0 3, 62 Unless they opt out for that accounting period under s 207I. F. Enforcement of financial reporting and disclosure obligations Under the CA, it is an offence to fail to comply with the applicable reporting standards.70 A company can be fined up to $50,000.00 while the directors can be fined that amount or can be imprisoned for up to two years. 71 Breaches of the financial reporting provisions of the FMCA are more strongly sanctioned. Breaches can be the subject of civil pecuniary penalties72 whereas knowing breaches of financial reporting standards on the part of the companies and directors can be the subject of criminal fines of up to $500,000.00 for directors and $2.5 million73 for companies. In addition, directors can be sentenced to up to five years in prison. In relation to the annual report required under the CA, it is an offence to fail to prepare an annual report;74 if convicted, a director could be fined up to $10,000.00.75 The annual report (including the financial statements and audit report, if prepared) must be made available to shareholders, either by sending a copy to shareholders or making it available electronically. Again, if this requirement is not met, the directors could be fined up to $10,000.00.76 66 Appendix 16 to the NZX Listing Rules. pp g NZX Main Board/Debt Market Listing Rules, cl 10.4 p 72 Financial Markets Conduct Act 2013, s 461M. 69 See the definition at cl 1.6.1 of the Listing Rules. 71 Companies Act, s207G and s373(3). D. Requirement to produce an annual report D. Requirement to produce an annual report Separate to the financial reporting requirements, the CA also requires large companies (as defined above), large overseas companies, companies that are public entities and companies with more than 10 shareholders 62 and all companies that are FMC reporting entities to produce an annual report.63 This report must, among other things, include a description of any change during the accounting period to the “nature of the business of the company or any of its subsidiaries” or “the classes of business in which the company has an interest” so far as is material to allow “the shareholders to have an appreciation of the state of the company’s affairs” and “will not be harmful to the business of the company or of any of its subsidiaries”.64 Companies with fewer than 10 shareholders can opt into this regime.65 E. Disclosure under the NZX Listing Rules 64 At s 211. 65 At s 207K. 7 7 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? Another potential source of corporate environmental reporting regulation would be the NZX Listing Rules. Indeed, the ASX has introduced a recommendation in its Corporate Governance Principles and Recommendations for a listed entity to “disclose whether it has any material exposure to economic, environmental and social sustainability risks, and if it does, how it manages or intends to manage those risks.” There is no such equivalent provision in the NZX Corporate Guidance. 66 While the NZX Listing Rules repeat and augment the CA requirements for an annual report,67 listed companies are not required to report on environmental impact. However, some environmental information may be required to be disclosed under the “Material information” provisions.68 The “Material information” provisions require listed companies to disclose information that “a reasonable person would expect, it if were generally available to the market, to have a material effect on the price of the Quoted Securities of the Issuer”.69 F. Enforcement of financial reporting and disclosure obligations 75 At s374(2). 70 Companies Act, s207G. 66 Appendix 16 to the NZX Listing Rules. 67 NZX Main Board/Debt Market Listing Rules, cl 68 At cl 10.1. 69 See the definition at cl 1.6.1 of the Listing Rules. 70 Companies Act, s207G. 71 Companies Act, s207G and s373(3). 72 Financial Markets Conduct Act 2013, s 461M. 73 At s461I. 74 Companies Act 1993, s 208(3). 75 At s374(2). 76 At s209(7) and s374(2). 77 Robert Costanza et al "The value of the world's ecosystem services and natural capital" (1998) 25 Ecological Economics 3. 78 Millenium Ecosystem Assessment Ecosystems and Human Well-being: Synthesis (Island Press, Washington, 2005) at 1. 79 At 4. 80 Millenium Ecosystem Assessment at 14; O. E. Sala et al. "Global biodiversity scenarios for the year 2100" (2000) 287 Science 1770. 81 Millenium Ecosystem Assessment at 14. G. Summary In summary, directors are agents of the company and owe duties to it. They have a very wide discretion to decide how to run the company, as long as it is done in good faith, and in the 8 8 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? best interests of the company, which usually means in the interests of the shareholders as a whole. The environment does not feature as a mandatory consideration when directors are making decisions nor do companies have any real obligation to report on their environmental impact. The disclosure requirements that companies do have are primarily financial. However, it would not matter if directors do not consider the environmental impact of the company if New Zealand’s environmental law completely protected the environment and required the remedying of any environmental damage caused. Part III will sketch the complex environmental issues that New Zealand and the globe faces while Part IV will identify the sources and coverage of New Zealand’s environmental laws to elucidate the areas where directorial discretion could have an impact. III. Environmental problems Humans are entirely dependent on ecosystem services for their survival and well-being. Ecosystems provide the air we breathe, the food we eat, the water we drink and many of the materials we use to construct our dwellings. Ecosystem services have been estimated to be worth on average $33 trillion US dollars per year (at a time when global Gross National Product was $18 trillion).77 While the last few decades of the twentieth century have seen a large increase on the material wellbeing of many people on the planet, this increased standard of living has come at the expense of ecosystem degradation around the globe. 78 One indicator of this degradation is the current extinction rate that is 1,000 times the background extinction rate.79 It is clear that many past practices in relation to the environment and the “business-as-usual” attitudes are unsustainable. Humans are eating into the planet's natural capital by exerting unprecedented and concerted pressure on ecosystems all around the world such that the balance of global nutrient cycles and the climate have been affected. The burning of fossil fuels, releasing carbon dioxide into the atmosphere which has been in storage for millions of years has had and is having a major influence on GHG levels, and hence on the climate. Satisfying the needs and wants of the burgeoning human population is influencing five drivers of global environmental change80 of which anthropogenic climate change is the most well-known. The other drivers are habitat loss (through land-use change and change to waterways), the spread of invasive species, pollution (particularly nitrogen deposition) and over-exploitation.81 These drivers are themselves driven by the processes that people utilise to satisfy their needs and wants. Land use change is viewed as the biggest driver of global 9 9 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? environmental change.82 As more land is taken from forest, wetland or grassland and put into agricultural production or into urban sprawl, not only is carbon dioxide often released to the atmosphere but native biodiversity is lost, new habitat is opened up for invasive colonisation and changes occur in the water and nutrient cycling in the area. New Zealand, unfortunately, has examples of all the global environmental drivers. III. Environmental problems Conversion of farm or forestry land to more intensive dairy farming, a common trend over the past decade, exemplifies agricultural intensification causing the release of carbon and also nitrogen pollution. While New Zealand’s average temperature rise is projected to be less than the global average,83 New Zealand will still feel the effects of rising sea levels, changes in rainfall patterns, an increase in flooding and drought and an increase in other extreme weather events.84 Being an island nation which relies heavily on agriculture, the effects of climate change on New Zealand could be considerable. The warming climate could also result in invasive species, including pests on agricultural and horticultural crops, being able to establish here. There are also threats to New Zealand’s native biodiversity, that in a warming world, New Zealand’s unique biota will be less able to compete with invasive plants and animals. As regards over-exploitation, a good example is the overfishing of orange roughy in a number of areas, requiring those areas to be closed for fishing at least a decade.85 Stocks have now rebounded enough to allow some fishing. 82 Sala, above n 81, at 1771. 83 B. Mullan, D. Wratt, S. Dean, M. Hollis, S. Allan, T. Williams, G. Kenny and MfE Climate Change Effects and Impacts Assessment: A Guidance Manual for Local Government in New Zealand (2nd ed, Ministry for the Environment, Wellington 2008) at 15. 84 At 14 At 14. 85 Ministry of Fisheries Sustainable New Zealand Seafood: Orange roughy (Ministry of Fisheries, October 2011). 86 Resource Management Act 1991, s 5(1). 87 At s 5 (2). 82 Sala, above n 81, at 1771. 83 B. Mullan, D. Wratt, S. Dean, M. Hollis, S. Allan, T. Williams, G. Kenny and MfE Climate Change Effects and Impacts Assessment: A Guidance Manual for Local Government in New Zealand (2nd ed, Ministry for the Environment, Wellington 2008) at 15. 84 At 14. 85 Ministry of Fisheries Sustainable New Zealand Seafood: Orange roughy (Ministry of Fisheries, October 2011). 86 Resource Management Act 1991, s 5(1). 87 At s 5 (2). 86 Resource Management Act 1991, s 5(1). 82 Sala, above n 81, at 1771. IV. New Zealand’s environmental protection laws It would be utterly astonishing if all this was known about the environment and yet New Zealand was doing nothing about it. New Zealand has an array of environmental laws dealing with different aspects of the drivers of ecosystem change. A. The Resource Management Act 1991 (“RMA”) The RMA is New Zealand’s primary environmental statute. It is a holistic statute that sets out a framework for making plans and decisions about use of the land, freshwater, air and coastal areas. Its purpose is “to promote the sustainable management of natural and physical resources”.86 “Sustainable management” is defined as:87 At 14. 85 Ministry of Fisheries Sustainable New Zealand Seafood: Orange roughy (Ministry of Fisheries, October 2011). 86 Resource Management Act 1991, s 5(1). 87 At s 5 (2) 10 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? managing the use, development, and protection of natural and physical resources in a way, or at a rate, which enables people and communities to provide for their social, economic, and cultural well-being and for their health and safety while— (a) sustaining the potential of natural and physical resources (excluding minerals) to meet the reasonably foreseeable needs of future generations; and 93 At ss 70A, 70B and 104E. 88 See ss 63 – 77D for provisions relating to regional and district plans. 89 See Part 6. 90 At s 6. 91 At s 7. 92 At ss7(i) and (j). 93 At ss 70A, 70B and 104E. 94 At s 15. 95 At s 14. 92 At ss7(i) and (j). (c) avoiding, remedying, or mitigating any adverse effects of activities on the environment. The RMA gives powers to layers of local government to make plans for their districts and regions. District plans and regional plans allow some activities to occur without the need for consent – these are “permitted activities”.88 When people want to carry out an activity that is not one of those activities, they must apply for a resource consent from the district or city council and potentially the regional council as well. 89 This process may involve public consultation. When decision makers are making decisions under the RMA, they must recognise and provide for “matters of national significance”90 – broadly the protection of the coastal and wetland areas, nationally significant landscapes, heritage areas, areas of indigenous diversity and areas of land and water significant to Maori. Decision makers must have particular regard to other factors including the efficiency of the use and development of resources, the efficiency of the end use of energy, the intrinsic value of ecosystems and maintenance and enhancement of the quality of the environment.91 Importantly, decision makers have to have regard to the effects of climate change and to the benefits to be derived from the use and development of renewable energy.92 However, decision makers are not allowed to have regard to whether a proposed activity or development will release GHGs.93 The rationale behind this is that climate change action is better left to central government action, rather than the ad hoc decisions of different councils around the country. In terms of global environmental drivers, the RMA may ameliorate the effect of land use changes as it prohibits emissions to air, land or water,94 unless the activities are specifically allowed for by a national policy statement (“NPS”), rule in a plan or resource consent. It also regulates the taking of water without consent.95 For all activities which do not meet the permitted activity threshold, an application must be prepared which contains an 95 At s 14. 11 11 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? environmental impact assessment 96 to determine whether the negative effects on the environment will be more than minor. Adverse effects must be avoided, remedied or as a last resort, mitigated.97 Conditions are placed on resource consents to minimise environmental impact. (c) avoiding, remedying, or mitigating any adverse effects of activities on the environment. If consent holders (or people operating where a consent would be required) do not comply with the relevant consent conditions or regulations, councils may take enforcement action.98 For newer consents, this process should be able to manage the environmental impacts many activities. However, there still many consents that were given in earlier time periods when standards were not as strict, resulting in residual damage to ecosystems which will not stop until those consents expire.99 In summary, the RMA is a comprehensive statute that facilitates the consideration of the various (sometimes divergent) values that are placed on the natural environment. The RMA does set out a complex framework of regulation at various levels; given the complex topic, this may well be appropriate. However, there are different criteria for the success of the RMA. According to the current National government and to developers, the RMA’s processes are cumbersome and add too much to the cost of development. There are moves towards changing the RMA which may yet eventuate.100 g (p y 101 Climate Change Response (Emissions Trading) Amendment Act 2008. , , 100 Nick Smith "RMA reform agenda outlined" (press release, 21 January 2015). 96 Resource Management Act 1991, s 88. 105 Climate Change Response Act 2002, ss 63 and 63A and Schedule 3. 106 97 At s 17. 99 See for instances ss 10, 10A, 10B and 20A. 99 See for instances ss 10, 10A, 10B and 20A. 106 At s 4(1). Part 4 and Schedule 3. g p 102 Climate Change Response Act 2002, s 3. g p g 102 Climate Change Response Act 2002, s 3. 103 Cameron, above n 5, at 247. 97 At s 17. 98 See Part 12 of the Act. 97 At s 17. 98 S P t 12 f th A t 97 At s 17. 98 S P t 12 f th A t 97 At s 17. 98 S P t 12 f th A t At s 17. 98 See Part 12 of the Act 103 Cameron, above n 5, at 247. 104 At 247. B. Climate Change Response Act 2002 In terms of climate change, New Zealand’s most important statute is the Climate Change Response Act 2002. In 2008, this Act was amended to include an emissions trading scheme.101 The New Zealand ETS (“NZETS”) is a measure contributing to New Zealand’s actions taken under the Kyoto Protocol.102 At the time of its introduction, it was envisaged as the first “all-sectors, all-gases”103 ETS. However, the NZETS was stripped back after the National government came into power in November 2008. The NZETS still includes “all- gases” meaning all six of the GHGs regulated by the Kyoto Protocol (carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulphur hexafluoride) 104 but the scheme no longer sets out a timeframe for all-sectors to be involved in the scheme. Under the NZETS, the GHG emissions from the importation or mining of liquid fossil fuel, natural gas and coal must be accounted for by the surrender of “units”.105 These units can be New Zealand Units (“NZU”) or Kyoto units or an approved overseas unit.106 Each NZU 12 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? allows the emitter to emit 1 tonne of carbon dioxide equivalent into the atmosphere. 107 However, “transitional” provisions introduced by the National government in 2009 and 2012, allow participants to surrender a unit for every two tonnes of GHG emissions. 108 These “transitional” amendments as cap the price of a unit at $25 per tonne.109 Importers and miners of liquid fossil fuel, natural gas and coal fuel must measure, record and disclose to the government the amount of carbon dioxide equivalent that will be emitted from the burning of the fossil fuel, natural gas and coal.110 At the end of the year, they must then surrender NZUs to the government, accounting for the amount of carbon dioxide equivalent that will have been emitted to the atmosphere that year by the burning of those energy sources.111 The importers/miners will pass down the cost of the NZUs onto their customers.112 Further down the chain, major industrial emitters may choose to take over the obligations for the energy sources that they purchase from up-stream participants. They may do so to better control the cost imposed on them by the NZETS. On the other side of the ledger, participants who carry out “removal activities” are entitled to receive NZUs. 107 Climate Change Response Act 2002, ss 4(1) and 63. 108 At s 63A. 109 At s 178A. 110 At ss 62 and 65. 111 At s 63. 112 Cameron, above n 5, at 249. 113 Climate Change Response Act 2002, ss 64 and 64A. 114 At s 57 and Schedule 4, Part 2. 115 At s 56 and Schedule 3, Part 1. 116 Climate Change Response (Emissions Trading and Other Matters) Amendment Act 2 117 Climate Change Response Act 2002, ss62 and 65 and Schedule 3. 118 See ss 80 – 86F. 119 At s 63A. 116 Climate Change Response (Emissions Trading and Other Matters) Amendment Act 2012, s 96. 117 Climate Change Response Act 2002, ss62 and 65 and Schedule 3. 118 6 107 Climate Change Response Act 2002, ss 4(1) and 63. 108 B. Climate Change Response Act 2002 113 “Removal activities” activities are listed in Parts 1 and 2 of Schedule 4 to the CCRA and include owning or leasing post-1989 forest land and producing goods that capture and store carbon are allocated NZUs. Post-1989 forestry owners are voluntary participants in the NZETS114 while owners of pre-1990 forests who deforest more than two hectares over a five year period are required to be participants.115 Excluding land use and land use changes, agriculture accounts for almost 50% of New Zealand’s carbon emissions. This is unusual for a developed country where emissions from agriculture are usually much lower.116 The farming lobby in New Zealand has exerted a strong influence over New Zealand’s climate policy – after the 2012 amendments, there is now no date to include biological emissions in the scheme, though certain agricultural participants do have to record and disclose to the government their carbon emissions.117 A number of factors have kept the price of emissions low on the NZETS which has limited its efficacy in incentivising emitters to change behaviour. One factor is the allocation of free NZUs to some industrial emitters. 118 Participants only have to surrender one NZU (or equivalent Kyoto credit) for every two tonnes of carbon dioxide emitted.119 The obligations to surrender emissions units could be met using international carbon credits from other Kyoto schemes. The resulting oversupply of credits in the market, pushed the going price down to 13 13 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? $2 per tonne of emissions in May 2013.120 A recent survey of participants in the NZETS indicates that the scheme is not having a positive impact on afforestation and may actually be encouraging deforestation as foresters may harvest while the carbon price is very low.121 The scheme is to be reviewed in 2015122 but given the National government’s previous stance on wanting to minimise the costs of emissions for emitters and for consumers, the chances of significant improvement seem unlikely. In relation to environmental disclosure, an important point is that the NZETS requires its participants to keep track of the GHG emissions that they are responsible for under the scheme.123 There are methodologies in place for the various calculations to take place. This could provide a useful background framework for a requirement for listed companies to disclose their emissions. 120 Richter and Chambers, above n 10, at 60. 121 Richter and Chambers, above n 10, at 63. 122 Cabinet Minute “Emissions Trading Scheme Review 2012: Final Decisions on Amendments to the Climate Change Response Act 2002” (2 July 2012) CAB Min (12) 23/10 at [111]. 123 Climate Change Response Act 2002, ss 62 and 65. 124 Alastair Cameron “Corporate and Commercial Issues” in Alastair Cameron (ed) Climate Change Law and Policy in New Zealand (LexisNexis NZ Ltd, Wellington, 2011) 393 at 395. 125 Ministry for the Environment, Environmental Snapshot: Legally protected conservation land in New Zealand (Ministry for the Environment, April 2010). 126 Ibid. 127 Wildlife Act 1953, s 67A. 128 At s 67A. B. Climate Change Response Act 2002 Some listed companies will already be participants in the NZETS which would make it easier for them to comply with a new environmental disclosure obligation. At the moment, NZETS participants only have to disclose their emissions to the government not to other stakeholders. Participants only have to disclose their emissions from some activities – for instance, oil companies would not have to record or disclose the emissions related to the running of their headquarters.124 120 Richter and Chambers, above n 10, at 60. 121 Richter and Chambers, above n 10, at 63. C. Other environmental statutes Protection of native biodiversity is also part of New Zealand’s environmental law and policy. Approximately 33% of New Zealand’s land area is set aside for conservation.125 This is a significant amount, though it is primarily in alpine areas;126 the majority of lowland areas have long since been converted to human use. Killing endangered fauna127 is an offence as is trading in endangered species.128 However, New Zealand’s conservation actions are more influenced by the amount of funding the Department of Conservation receives than by the law itself. In New Zealand, conservation of native flora and fauna is often a matter of protecting indigenous biodiversity from the effects of invasive species, particularly mammals. New Zealand’s fauna is vulnerable to mammalian predators as it evolved without mammals until the arrival of humans and their associated mammals. The Biosecurity Act 1993 is also important here as it controls what organisms are allowed to come into New Zealand. Again, funding levels have a significant effect on the action in this area. 14 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? In terms of over-exploitation, New Zealand has a quota management system for its fisheries, set at a “sustainable level”.129 It also has entered into international agreements to prevent certain destructive fishing practices.130 Another statute that could be classed as being environmental law is the Waste Minimisation Act 2008. This sets up a framework encouraging producers to consider the lifecycle of their products and provides for voluntary schemes which producers can enter into to increase efficiency and decrease waste.131 It also sets out the responsibilities of territorial authorities in relation to waste management and minimisation.132 129 Fisheries Act 1996. 130 Ministry of Foreign Affairs & Trade "Treaties and International Law: International Fisheries" http://mfat govt nz 129 Fisheries Act 1996. 130 Ministry of Foreign Affairs & Trade "Treaties and International Law: International Fisheries" http://mfat.govt.nz . 131 Waste Minimisation Act 2008, Part 2. 132 See Part 4. 133 Smith, above n 100. 129 Fisheries Act 1996. 133 Smith, above n 100. http://mfat.govt.nz . 131 Waste Minimisation Act 2008, Part 2. 132 132 See Part 4. D. Summary Like other developed countries, New Zealand has a system of environmental law addressing some of the drivers of ecosystem change. However, whether these laws have the capacity to keep New Zealand’s environmental impacts to sustainable levels in the long-term is debatable especially as the current National government has shown little appetite to strengthen measures to combat climate change and is foreshadowing changes to the RMA to make it friendlier for developers.133 In summary, the law provides a minimum amount of protection for the environment. E. Scope for directors to use their power for good of the environment However there is significant scope for the exercise of company directors’ discretion to improve environmental outcomes, by refraining from taking environmentally damaging actions or by actively promoting environmental health. An obvious example is firms choosing to reduce their GHG emissions as there is no requirement for companies to do so at the moment. Exercising discretion by entering into a voluntary waste minimisation scheme would be beneficial under the Waste Minimisation Act. Companies have choices about what to produce – whether it is legal to carry out an environmentally damaging production process does not mean that a company has to take that step. Companies also have choices about where to get their supplies from and so can choose to buy from suppliers who are minimising their environmental impact – for instance by using timber sourced from forests that have been certified by the Forest Stewardship Council. Companies also have choices about where to invest their profits – again they can choose to invest in less environmentally damaging enterprises. Companies can also exert influence over consumer opinion and over government policy. Companies could improve environmental outcomes by lobbying for regulation to protect the environment or at least not lobby against legislation leading to more sustainable outcomes. Companies could positively influence consumer opinion on environmental issues 15 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? – for instance by encouraging higher density housing development, thereby reducing urban sprawl. As it stands, the framework under the RMA may allow for a sprawling subdivision or a higher density apartment building. It is the developer’s choice as to which option to apply for. 134 Resource Management Act 1991, s 114(3). F. Disclosure obligations in environmental law The preceding analysis of New Zealand’s company law and environmental law identifies that companies, including listed companies, do not currently have any obligation to report to shareholders or the public about their environmental impact. Companies applying for resource consents must assess the environmental impact of the activity they want to undertake, and if the consent is successfully obtained, they will likely have to monitor the ongoing environmental impact of the consented activity. These impacts must be reported to the relevant local authority. While resource consents are publically available on request,134 there will usually be no requirement on the company to disclose the environmental effect of the consented activity to the public. Companies who are participants in the NZETS must keep records of their carbon emissions or of the amount of liquid fuel, natural gas or coal that they mine or import. This must be disclosed to the government so that the company surrenders the correct number of emissions units. Again, there is no requirement to disclose this information to shareholders or to the public. Shareholders and the general public therefore are dependent on the voluntary disclosures of companies to assess their environmental impacts. V. Voluntary responses by New Zealand companies to environmental problems V. Voluntary responses by New Zealand companies to environmental problems Before a legislative requirement is put in place to require companies to consider the environment or to disclose environmental impacts, it is sensible to assess whether voluntary efforts by New Zealand companies are fulfilling those goals. Voluntary disclosures by New Zealand companies (particularly listed companies) are important in the assessment of both parts of the question; the primary way that the public or shareholders determine how directors are exercising their discretion when it comes to the environment is by examining the environmental information that companies voluntarily disclose. However, as it stands, with no mandatory environmental reporting standard, it is easy for companies to just report good news, and little if any of the bad. A number of New Zealand companies do now produce some sort of “sustainability report”. Overall, New Zealand’s level of corporate reporting on sustainability is low – 16% of New 16 16 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? Zealand companies report on sustainability issues compared to a global average of 31%.135 The reporting rate is much higher for the 100 largest companies in many countries but New Zealand’s reporting rate is still behind the global average: of the top 100 companies in each of 41 countries KPMG surveyed, 71% of companies reported on corporate social responsibility (“CSR”) 136 issues, 137 compared to 47% of New Zealand’s top 100 companies.138 New Zealand companies are involved in a number of reporting networks. For instance, there are 33 New Zealand entities with reports on the Global Reporting Initiative’s (“GRI”) Sustainability Disclosure Database,139 including local bodies, state-owned enterprises, listed companies and others. However, only three so far have uploaded reports for the 2014 year and only 12 for the 2013 year.140 The GRI, as its name suggests, is a global reporting initiative which promulgates a set of sustainability reporting guidelines. It is the most popular reporting system with large companies globally.141 These guidelines are used by 78% of N100 companies from the 41 countries surveyed by KPMG who prepare CSR reports refer to these guidelines.142 According to KPMG’s survey of New Zealand’s largest 100 companies, more than half of the companies who prepared reports referred to the GRI guidelines. The GRI is a not-for-profit organisation promoting sustainability reporting. 135 Grant Thornton "Corporate social responsibility: beyond financials" <www.internationalbusinessreport.com> at 12. 136 Corporate social responsibility more generally will be discussed in Part VI. 137 KPMG International The KPMG Survey of Corporate Responsibility Reporting 2013 (KPMG International, 2013) at 20. 138 At 25. 139 Global Reporting Initiative "Sustainability Disclosure Database" <http://database.globalreporting.org/>. 140 Global Reporting Initiative "GRI Reports List”, available from <http://database.globalreporting.org/> accessed on 2 February 2015. 141 KPMG International, above n 137, at 30. 142 At 11. 143 Global Reporting Initiative “What is GRI?” <www.globalreporting.org>. 144 Carbon Disclosure Project “About Us” <www.cdp.net>. 9 Global Reporting Initiative "Sustainability Disclosure Database" <http://database.globalreporting.org/>. 0 Global Reporting Initiative "GRI Reports List”, available from <http://database.globalreporting.org/> cessed on 2 February 2015. 135 Grant Thornton "Corporate social responsibility: beyond financials" <www.internationalbusinessreport.com> at 12. 136 143 Global Reporting Initiative “What is GRI?” <www.globalreporting.org>. V. Voluntary responses by New Zealand companies to environmental problems It works with business, civil society and other stakeholders to prepare the guidelines. The guidelines require companies to report on environmental, social and human rights issues. It also provides for companies to report on supply chain sustainability. Sustainability reports prepared in accordance with GRI guidelines also “presents the organization’s values and governance model, and demonstrates the link between its strategy and its commitment to a sustainable global economy.”143 Another global reporting movement is the Carbon Disclosure Project. This is a group representing 767 institutional investors holding US$92 trillion in assets, helping to reveal the risk in their investment portfolios.144 Surveys about environmental impact and risk and GHG emissions are sent to the world’s largest companies. In New Zealand, the surveys are sent to the NZX50, while in Australia, the surveys are sent to the ASX200. The individual results for each company are put on the CDP website unless the company indicates that the results are only to be seen by CDP’s institutional investor members. Either way, the reporting score 135 Grant Thornton "Corporate social responsibility: beyond financials" <www.internationalbusinessreport.com> at 12. 17 17 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? for each company will be released. In 2014, only 17 companies listed on the NZX responded to the CDP survey, with scores ranging from 10 to 98 out of a possible 100.145 The scores reflect the comprehensiveness of reporting rather than the amount of carbon dioxide being released to the atmosphere. The majority of NZX50 companies did not respond to the survey. The response rate is down from the previous year when 42% of NZX50 companies responded to the CDP survey, representing 92% of total market capitalisation.146 Another group that supports sustainability reporting is the New Zealand Sustainable Business Council (“SBC”). SBC members must report to the SBC their carbon footprint within one year of becoming a member and on their plans to reduce carbon intensity within two years of joining.147 Within three years of joining, a member must prepare a “sustainable development report demonstrating that member’s progress on environmental, social and economic performance”148 – often referred to as a “triple-bottom-line report”. The SBC encourages its members to report to the GRI standards. 145 CDP Australia & NZ CDP 2014 ASX 200 Climate Leadership Awards (Carbon Disclosure Project, Australia, 2014). 146 CDP Australia and New Zealand Climate Change Report 2013 (Carbon Disclosure Project, December 2013) at 12. 147 Sustainable Business Council “Terms of Membership” <www.sbc.org.nz> at [4(g) – (h)]. 148 At [4(a)]. 149 Sustainable Business Council “SBC Sustainable Development Principles” <www.sbc.org.nz>. This definition comes from the Brundtland Report – World Commission on Environment and Development, Our Common Future (1987). 150 Markus J Milne, Helen Tregidga and Sara Walton “Words not actions! The ideological role of sustainable development reporting” (2009) 22 Accounting, Auditing & Accountability Journal 1211 at 1241. 151 Sustainable Business Council “Our Members” <www.sbc.org.nz>. 152 CDP Australia & NZ, above n 145. p p g ( ) g, g 151 Sustainable Business Council “Our Members” <www.sbc.org.nz>. ( ) 150 Markus J Milne, Helen Tregidga and Sara Walton “Words not actions! The ideological role of sustainable development reporting” (2009) 22 Accounting, Auditing & Accountability Journal 1211 at 1241. 152 CDP Australia & NZ, above n 145. [ ( )] 149 Sustainable Business Council “SBC Sustainable Development Principles” <www.sbc.org.nz>. This definition comes from the Brundtland Report – World Commission on Environment and Development, Our Common Future (1987). 152 CDP Australia & NZ, above n 145. V. Voluntary responses by New Zealand companies to environmental problems SBC members commit to the process of “sustainable development” namely “development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” 149 However, analysis of the discussion of sustainable development in members’ reports and in communications from the SBC suggests support for the perpetuation of the status quo rather than re-examining whether current business practices can ever be sustainable in the long- term.150 As at 3 December 2014, the SBC has 68 member businesses, including Fonterra.151 However, only nine entities in the NZX50 are members of the SBC. While a reasonable number of New Zealand’s top 50 companies have started reporting on CSR issues (including environmental issues), more than half of those companies consistently do not report on these issues. When it comes to smaller companies, the numbers are even lower. The standard of reporting varies widely between companies – for instance, New Zealand responses to the CDP 2014 ranged from 10 out of 100 (very low) to 98 out of 100 (very high).152 In summary, reporting is voluntary, ad hoc and varies widely in quality. 152 CDP Australia & NZ, above n 145. 18 18 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? VI. Justifying legislative intervention in the relationship between companies and the environment Having established that there are opportunities within New Zealand’s framework of environmental law for directors of companies to use their discretion to improve environmental outcomes, the question becomes whether directors should have to exercise their decision-making discretion in favour of the environment. To put it another way, would it be justified for the state to require companies to interact with the environment in a sustainable manner? If not, should directors have to take into account the environmental impact of the company’s actions even if they do not act in a sustainable manner? A. Purpose of companies 153 Surya Deva Regulating corporate human rights violations: humanizing business (Routledge, London & New York, 2012) at 131; James McConvill and Martin Joy "The interaction of directors' duties and sustainable development in Australia: setting off on the uncharted road" (2003) 27 Melb.U.L.Rev. 116 at 117. 154 Richard Holme and Phil Watts Corporate social responsibility: making good business sense (World Business Council on Sustainable Development January 2000) at 10 153 Surya Deva Regulating corporate human rights violations: humanizing business (Routledge, London & New York, 2012) at 131; James McConvill and Martin Joy "The interaction of directors' duties and sustainable development in Australia: setting off on the uncharted road" (2003) 27 Melb.U.L.Rev. 116 at 117. 154 Richard Holme and Phil Watts Corporate social responsibility: making good business sense (World Business Council on Sustainable Development, January 2000) at 10. p y 155 Deva, above n 153, at 120; Jason C Jones “Environmental Disclosure: Toward an Investor Based Corporate Environmentalism Norm” (2010) 20 BU Pub. Int. LJ 207 at 216. , , ; Environmentalism Norm” (2010) 20 BU Pub. Int. LJ 207 at 216. p , y ) 155 Deva, above n 153, at 120; Jason C Jones “Environmental Disclosure: Toward an Investor Based Cor Deva, above n 153, at 120; Jason C Jones Environmental Disclosure: Toward an Investor Based Co Environmentalism Norm” (2010) 20 BU Pub. Int. LJ 207 at 216. York, 2012) at 131; James McConvill and Martin Joy The interaction of directors duties and sustainab development in Australia: setting off on the uncharted road" (2003) 27 Melb.U.L.Rev. 116 at 117. 154 Richard Holme and Phil Watts Corporate social responsibility: making good business sense (World Council on Sustainable Development January 2000) at 10 , ) ; y evelopment in Australia: setting off on the uncharted road" (2003) 27 Melb.U.L.Rev. 116 at 117. 4 Richard Holme and Phil Watts Corporate social responsibility: making good business sense (World Bus A. Purpose of companies Whether companies should have to interact with the environment in a sustainable way or take into account the environmental impact of a company’s actions, brings into question the purpose of companies. Wealth creation and profit maximisation are commonly thought to be the reasons for the existence of companies.153 While these goals undoubtedly underlie the existence of many companies, it is increasingly recognised that these goals cannot be pursued at all costs. There are differing opinions however about the extent of the limitations that should be put on a company’s actions or, to put it in a positive sense, the scope of a company’s responsibility to society. The name given to this general concept is “corporate social responsibility”. A well-used definition of CSR is that of the World Business Council on Sustainable Development:154 Corporate social responsibility is the commitment of business to contribute to sustainable economic development, working with employees, their families, the local community and society at large to improve their quality of life. B. Milton Friedman – "The social responsibility is to increase its profits" B. Milton Friedman – "The social responsibility is to increase its profits" Whether companies should owe any duties except to shareholders has been the subject of debate in the United States since the 1930s with Professors Berle and Dodd arguing whether directors should only act in the interests of shareholders or whether they should also act in the interests of other stakeholders.155 Since that time, the most famous proponent of the view that companies must act in the interests of shareholders only is the Chicago economist Milton Friedman. He famously wrote an article titled “The social responsibility is to increase its 19 19 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? profits”.156 He argued that maintaining that businesses had social responsibilities was akin to socialism. As he saw it, businesses that used profits to benefit the environment or other stakeholders were effectively taxing their customers or their shareholders and deciding how the proceeds would be spent without any of the accountability of elected politicians. A. Purpose of companies According to Friedman, business’ responsibility is “to use its resources and engage in activities designed to increase its profits so long as it stays within the rules of the game, which is to say, engages in open and free competition without deception or fraud.” 157 Friedman was not opposed to spending on community initiatives or other such activities that increased the goodwill of the community and were in the long term interest of the company – he just disdained the label of “social responsibility” as “hypocritical window-dressing”. He was also not opposed to pollution regulation (at least in this article) provided that companies did not go beyond their legal requirements. He disdained activist stockholders who sought to persuade companies to go beyond their legal obligations when the activists had been unsuccessful in using the political process to justifiably change the rules of the game. 156 Milton Friedman “The social responsibility of business is to increase its profits” The New York Times Magazine 13 September 1970. 157 Ibid 161 At 126 – 127 – emphasis in original. 156 Milton Friedman “The social responsibility of business is to increase its profits” The New York Times Magazine 13 September 1970. 157 Ibid. 158 Deva, above n 153, at 122. 159 123 124 At 123 – 124. 160 At 125. 158 Deva, above n 153, at 122. 159 At 123 – 124. 159 At 123 – 124. 160 At 125. 156 Milton Friedman “The social responsibility of business is to increase its profits” The New York Times Magazine 13 September 1970. 157 Ibid. 158 Deva, above n 153, at 122. 159 At 123 – 124. 160 At 125. 161 At 126 – 127 – emphasis in original. Magazine 13 September 1970. 157 Ibid. 158 Deva above n 153 at 122 C. Critique of Friedman Friedman’s views must be put in the context of the time – during the Cold War when, as Deva points out, any derogation from free markets was seen as a threat to capitalism as a whole.158 However, CSR discourse is quite far from socialism. It only arises where private companies hold positions of power and influence within an economy, such that their effects on society can be seen.159 Deva (among other CSR theorists) presents a convincing critique of Friedman’s thesis. One of the underlying premises to Friedman’s argument is that shareholders are the owners of the business and so have a right to control it.160 It is they who are taking the risk – if the company becomes insolvent, it is their money that will be lost. This approach does not take into account the contributions made and the risks taken by other stakeholders:161 [E]mployees contribute by putting in labour, supply chains contribute by making available necessary materials and other inputs, consumers contribute by buying goods or services, and governments contribute by maintaining law and order and by creating a business-favourable regulatory environment. All these stakeholders contribute to the working and success of corporations, and take different kinds of risks while making their respective contributions. From an environmental standpoint, shareholders may be taking a financial risk but by damaging the environment or depleting natural capital, companies are risking the wellbeing 161 At 126 – 127 – emphasis in original. 20 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? of the rest of society, now and in the future. Given the risks taken by other stakeholders, it is reasonable that companies should have to balance their interests as well when making decisions. Friedman also ignores the commonalities between shareholders and other stakeholders – shareholders are members of society as well, and have an interest in protecting the environment.162 These interests do not disappear as soon as they invest in a company. Deva also argues that Friedman’s “CSR spending as tax” is misconceived. Spending on environmental or community initiatives can only be seen as taxation or theft if shareholders have a right to certain level of profit, rather than just an expectation of some profit.163 There are many reasons why profits would not reach a maximal level – and these factors would not be seen as “taxation”.164 163 At 128. 164 Deva gives the example of paying adequate salaries to employees. 165 At 140 141 At 140 141. 166 Boston and Lempp, above n 11, at 1006. 162 At 127. 163 At 128. 164 Deva gives the example of paying adequate salaries to employees. 165 At 140 – 141. 166 Boston and Lempp, above n 11, at 1006. 166 Boston and Lempp, above n 11, at 1006. D. The "business case" for sustainability Friedman’s thesis also suggests that “CSR” initiatives that are profitable should be undertaken – in effect that there should be a business case for some CSR activities. The business case for acting in an environmentally sustainable way is based on there being a competitive advantage to it; that by acting sustainably a business will be more profitable as consumers will prefer their products to those of businesses who do not act sustainably. This is now a commonly used argument to encourage companies to become more socially or environmentally responsible. As Deva explains (in the context of human rights), these sorts of arguments rest on a number of key assumptions; that consumers know about the sustainability practices of various companies (and the products associated with them) and care enough to make buying decisions on that basis. 165 It also assumes that consumer preference will generate enough profit to make the shift worthwhile. These assumptions will not hold true in many situations. The reality is that changing to a low-carbon and environmentally sustainable society will be a costly process for a number of businesses. Some industries will be fundamentally altered. In fact, the cost on business is one of the contributing factors identified by Boston and Lempp resulting in climate change inaction in democratic countries.166 The “interest group” asymmetry arises because the costs of change to a low-carbon society will fall on concentrated groups, particularly businesses in carbon- intensive industries, while the benefits of the change will be more widely spread in society and over time. The groups who will bear the cost are better organised and have an incentive to lobby government to delay action. The danger in the focus on “business case” arguments is that companies will only take action on sustainability when it is going to be profitable for them. In order to present a positive impression, companies will report the profitable sustainability actions they have undertaken 21 21 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? and rather than acknowledge their continuing unsustainability, instead suggest that they are being sustainable.167 For example, in a study looking at the sustainability reports of members of the SBC, the authors concluded that:168 With the exception of one NZBCSD [SBC] member (Landcare Research), ecology, and a wider systems understanding of sustainability, remains largely absent from the constructions of sustainability we have examined. 167 Gray, Rob “Does sustainability reporting improve corporate behaviour?: Wrong question? Right time?” (2006) 36 Accounting and Business Research 65 at 81. 168 5 D. The "business case" for sustainability Business talk of sustainability seems likely to compel us ‘to adopt a narrow economic language, standard of judgement, and world view in approaching and utilising the Earth’ The point is that in the long run, businesses should not be allowed to be profitable if certain environmental or human rights standards are not being met. For this to happen, environmental costs are going to need to be taken into account. But before then, businesses should not pretend that true sustainability is achievable by making minimal changes to business as usual. This is not to say that such changes are not useful but it should be acknowledged that sustainability is about more than just energy efficiency. The reason why changes should be made is because companies have a moral responsibility to account for the impacts of their actions, not because they are going to be profitable.169 E. The moral obligations of companies At 147. 172 James Rachels The end of life: euthanasia and morality (Oxford University Press, Oxford; New York; London, 1986) at 180. 173 [1932] AC 562 (HL) at 580. 169 Deva, above n 153, at 141. g 168 Milne et al., above n 50, at 1241. g 168 Milne et al., above n 50, at 1241. 169 169 Deva, above n 153, at 141. 170 171 At 147. 170 At 146. At 147. 2 James Rachels The end of life: euthanasia and morality (Oxford University Press, Oxford; New York; ondon 1986) at 180 Milne et al., above n 50, at 1241. 9 Deva, above n 153, at 141. 0 At 146 E. The moral obligations of companies So what are the moral obligations of a company? Deva argues that companies are, like natural people, “social organs” who “ought to comply with basic moral and legal norms of society”. After all, companies “consist of the people, [are] operated by the people and exist for the people”.170 Natural persons are social organs and “their social status should not cease to exist merely because they decide to act collectively and in an artificial form.”171 The moral obligations that shareholders have towards other members of society should not be shielded by the corporate veil. To put it another way, just by empowering an agent to act for a person, the principal cannot rid him or her or itself from moral responsibility for the actions the agent takes under his, her or its instruction. The basic duty that moral agents have is not to cause harm to others. People are free to act to the extent that their actions do not harm others.172 In law, this was expressed as the “Neighbour Principle” in the famous tort case of Donoghue v Stevenson:173 22 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? The rule that you are to love your neighbour becomes in law, you must not injure your neighbour; … You must take reasonable care to avoid acts or omissions which you can reasonably foresee would be likely to injure your neighbour. As set out in Part II, global environmental change is being driven by human needs and wants. Burning fossil fuel to support current lifestyles in the Western world can be reasonably be foreseen to cause harm to future generations through further climate change. Altering ecosystems through nutrient pollution and agricultural intensification causing degraded water and soil quality can also be reasonably foreseen to cause harm to present and future generations. Future generations (including young people alive today) will have to live with the harm caused by the unsustainable practices that count as business as usual now. When the phrase “environmental cost” is used, it can be looked at as meaning a cost that someone else is going to have to incur if they want to have the same ecosystem services that current generations are overexploiting for free. g ( ) Policy in New Zealand (LexisNexis NZ Ltd, Wellington, 2011) 127 at 135 – 136. 176 At 136 Deva, above n 153, at 147 148. 5 Peter Wilson “The Economics of Emissions Trading” in Alastair Cameron (ed) Climate Change Law and 4 Deva, above n 153, at 147 – 148. 5 P t Wil “Th E i f E i i T di ” i Al t i C ( d) Cli Ch L d E. The moral obligations of companies While a tort claim is unlikely to be useful to future generations, the Neighbour Principle is one of the basic norms of society and companies should abide by it to the fullest extent possible.174 F. Balancing wellbeing against environmental harm 174 Deva, above n 153, at 147 – 148. 174 Deva, above n 153, at 147 – 148. g ( ) g y in New Zealand (LexisNexis NZ Ltd, Wellington, 2011) 127 at 135 – 136. 136 , , 175 Peter Wilson “The Economics of Emissions Trading” in Alastair Cameron (ed) Clim above n 153, at 147 – 148. Wilson “The Economics of Emissions Trading” in Alastair Cameron (ed) Climate Change Law and F. Balancing wellbeing against environmental harm Having established that companies do broadly owe a moral duty to avoid environmental harm, should this duty be quantified legally and if so, to what extent? To have an absolute legal duty to not emit any GHGs or to not use nitrogen fertiliser for instance would be counter-productive, as people currently derive great benefit from those environmentally- unsustainable activities. In economic terms, environmental damage is a negative externality– it is a cost that is being placed on a “party external to the decision making”. 175 This means that more environmentally damaging goods and services are being produced than is societally optimal.176 To reduce production to more societally acceptable levels, a mechanism should be put in place (such as a tax or trading scheme) so that producers have to take into account the effect their activities are having on others.177 Prices on those goods or services would go up and fewer would be consumed. However, the key point is that those goods and services will still be produced if people will pay the higher prices. The optimal amount of emissions is not going to be zero because people will pay higher prices for the things they really value.178 The change to a more sustainable relationship between economy and environment cannot happen overnight – at best it will take decades. According to current predictions from the International Energy Agency, if states want to keep global warming to under 2°C, carbon 23 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? emissions do not have stop straight away but global emissions need to peak by 2017.179 The ideal solution would be an international agreement to reduce GHG emissions drastically. States could then set about putting in place mechanisms to incentivise emitters to decrease emissions to the targeted level with the reassurance that everyone else will be doing the same. However, this seems unlikely to happen given that negotiations have been going on for more than two decades180 and still there is no agreement as to the details of emissions reductions. Strengthening the NZETS would assist in incentivising emitters to decrease emissions. The carbon price however, would need to be much higher in order to do that and the National government has not evinced willingness to increase the price in the New Zealand market. F. Balancing wellbeing against environmental harm In this context, it would be detrimental to the economy of New Zealand to impose a strict obligation on New Zealand companies to drastically cut emissions and other environmental damage. Doing nothing to incentivise decreasing emissions and other environmental damage would not be helpful. Companies should be encouraged to prepare for a low-carbon future so that a “smooth transition” can occur, as mentioned in the introduction. Measurement and disclosure of environmental impact is an important first step. Strategic decisions about minimising environmental damage while remaining profitable can only made when companies (and governments) have information about the emissions and other environmental impacts of companies. 180 Vernon Rive “International Framework” in Alastair Cameron (ed) Climate Change Law and Policy in New Zealand (LexisNexis NZ Ltd, Wellington, 2011) 49 at 53 – 54. 179 International Energy Agency World Energy Outlook 2012: Executive Summary (OECD/IEA, France, 2012) at 3. 180 V Ri “I t ti l F k” i Al t i C ( d) Cli t Ch L d P li i N 179 International Energy Agency World Energy Outlook 2012: Executive Summary (OECD/IEA, France, 2012) at 3. 180 Vernon Rive “International Framework” in Alastair Cameron (ed) Climate Change Law and Policy in New Zealand (LexisNexis NZ Ltd, Wellington, 2011) 49 at 53 – 54. 181 David Norton and Nick Reid Nature and Farming: sustaining native biodiversity in agricultural systems (CSIRO Publishing, Collingwood, Victoria, 2013). 182 United Nations Global Compact “The Ten Principles” <www.unglobalcompact.org>. The UNGC originally had nine principles; the tenth principle relating to anti-corruption was added in 2004. 183 United Nations Global Compact “Business Participation” <www.unglobalcompact.org>. 184 United Nations Global Compact “Overview of the UN Global Compact” <www.unglobalcompact.org>. 185 United Nations Global Compact “Participant Search” <www.unglobalcompact.org>. 186 United Nations Global Compact “The Ten Principles” <www.unglobalcompact.org>. 187 United Nations Global Compact “The Ten Principles” <www.unglobalcompact.org>. 188 United Nations Global Compact “What is a COP?” <www.unglobalcompact.org>. 189 United Nations Global Compact “The Ten Principles” <www.unglobalcompact.org>. G. Summary As identified in Part II, New Zealand’s company law is shareholder-focussed. Directors have to act in the best interests of the company, which are usually the interests of shareholders as a whole. Only when a company’s solvency is threatened are the company’s best interests not identified with shareholders, but rather with creditors. The interests of shareholders as a whole are thought to be the maximisation of profits, unless otherwise specified. This paper will now go on to explore three options for incorporating environmental impact considerations into New Zealand’s corporate decision making; directors voluntarily considering the environment, imposing a legal duty to take into account the environmental impact of the company’s action or imposing a legal duty to interact with the environment in a sustainable manner. Part VII will consider voluntary options, namely either joining the SBC or joining the UNGC, which is a voluntary, collaborative initiative between the United Nations and businesses to achieve human rights, environmental protection and anti- corruption objectives. It is principles-based and requires disclosure of a company’s progress towards implementing the principles. The difference between this option and the other two is that reporting would be voluntary. Hence this section will include an analysis of the efficacy of voluntary reporting in achieving adequate disclosure. The second option, the requirements in the UK Companies Act 2006 requiring directors to take into account the environment in 24 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? decision making, will be examined in Part VIII. The third option, to be examined in Part IX, is an additional directors’ duty to act in an environmentally sustainable manner, which is not currently in place in any common law country. All three options would involve companies measuring and disclosing their environmental impacts. However, none of the options requires companies not to seek to make a profit; a company cannot be green if it is continually in the red.181 Companies need to make profits to continue to exist. Investors will not want to invest money where there is no return and people will not work for a company if they are not paid. The point is to make a profit while taking into account environmental cost. VII. Voluntary initiatives -the UNGC, the SBC and the SBN A. Introduction to the UNGC The UNGC is a set of ten principles182 that companies can choose to adopt. It is a “leadership initiative, involving a commitment by a company’s Chief Executive Officer (or equivalent), and supported by the highest-level Governance body of the organization (eg, the Board).”183 The UNGC was proposed by the then UN Secretary General Kofi Annan in January 1999 and was officially launched in July 2000. There are now more than 12,000 participants, 184 including businesses and other organisations from 145 countries. Currently, there are four New Zealand participants in the UNGC; three small to medium enterprises (“SMEs”) and one foundation.185 The principles are derived from the Universal Declaration of Human Rights, the International Labour Organization’s Declaration on Fundamental Principles and Rights at Work, the Rio Declaration on Environment and Development and the United Nations Convention Against Corruption. 186 As the UNGC website describes “The UN Global Compact asks companies to embrace, support and enact, within their sphere of influence, a set of core values in the areas of human rights, labour standards, the environment and anti- corruption.” 187 Participation in the UNGC is voluntary and except for detriments to a company’s reputation, there are no repercussions for breaching the principles. Participants must report on their progress every year – if a company does not report, then it will be removed from the register of participants.188 There are three principles in the UNGC that relate to the environment:189 There are three principles in the UNGC that relate to the environment:189 190 Rio Declaration on Environment and Development A/CONF.151/26 (1992), Principle 15. 191 United Nations Global Compact "Global Compact Principle 8" <www.unglobalcompact.org>. 192 United Nations Sustainable Development Agenda 21, at para 34.1. 193 United Nations Global Compact “Local Networks” <www.unglobalcompact.org>. 194 United Nations Global Compact Guide for responsible corporate engagement in climate policy: a caring for climate report (UNGC, 2013) 195 Afshin Akhtarkhavari, “The Global Compact, Environmental Principles, and Change in International Environmental Politics” (2009) 38 Denv. J. Int'l L. & Pol'y 277 at 305. 196 Deva, above n 153, at 97. 197 United Nations Global Compact “The Ten Principles” <www.unglobalcompact.org>. Principle 9: encourage the development and diffusion of environmentally friendly technologies. Principle 7 is derived from the 1992 Rio Declaration which states that “where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation”. 190 Principle 8 is essentially the idea that businesses “have the responsibility to ensure that activities on our own yard should not cause harm to the environment of our neighbours.”191 The environmentally friendly technologies referred to in Principle 9 are defined in Agenda 21 as technologies that “protect the environment, are less polluting, use all resources in a more sustainable manner, recycle more of their wastes and products and handle residual wastes in a more acceptable manner than the technologies for which they were substitutes.”192 There are three principles in the UNGC that relate to the environment:18 Principle 7: Businesses should support a precautionary approach to environmental challenges 25 25 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? 197 United Nations Global Compact “The Ten Principles” <www.unglobalcompact.org>. Principle 8: undertake initiatives to promote greater environmental responsibility; and Principle 8: undertake initiatives to promote greater environmental responsibility; and Principle 9: encourage the development and diffusion of environmentally friendly technologies. B. How well is it working? The UNGC can be regarded as successful in some respects. It has a truly global membership as well as having local networks of participants in more than 20 countries, encouraging collaboration between companies about the principles.193 The Compact requires participants to at least consider the principles once a year when the Communication on Progress is filed. It also produces resources that can be used by members. For instance, the UNGC, in partnership with the CDP and the World Wildlife Fund, among others released guidance for companies to positively engage with governments over climate policy. 194 The UNGC is based on the idea of collective learning. The principles are aspirational; members are to report on progress made rather than on standards fulfilled. It also allows businesses to interpret the principles in their own way. This can be regarded as an advantage or disadvantage. On the positive side, it could encourage companies to join the UNGC who otherwise may not if they had to comply with more stringently defined principles.195 Once in, these companies may be influenced by the interpretations of other companies and come to view their relationship with the environment and with stakeholders in a different way. On the other hand, companies are able to interpret the principles a way that is contrary to the plain meaning of the words. 196 For example in relation to Principle 3 of the UNGC, that “Businesses should uphold… the effective recognition of the right to collective bargaining”, 197 which seems on the face of it to require businesses to “institutionalize 26 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? ‘collective bargaining’, it [BHP] continued to require its new employees to sign individual contracts and disputed that Principle 3 directed that employment be based on collective bargaining.”198 The Global Compact Office seemed to agree.199 The UNGC has been the subject of much academic discourse over its 15 year life, examining the types of companies that enter it, the types of companies that delist from it and the impact it has on the companies who join. One such study examined whether US companies entering the UNGC were using it to “blue-wash” their public image.200 This is a concern given the relatively low membership fee and the less than onerous obligation to produce a Communication on Progress once a year. g 206 Sustainable Business Council “Sustainable Development Principles” <www.sbc.org.nz>. 198 Deva, above n 153, at 97. At 18. 204 United Nations Global Compact “How do I prepare a COP? Advanced” <www.unglobalcompact.org>; Sustainable Business Council “Sustainable Development Reporting Guide” <www.sbc.org.nz>. 205 Sustainable Business Network “About the Sustainable Business Network” <sustainable.org.nz> 206 Sustainable Business Council “Sustainable Development Principles” <www.sbc.org.nz>. 200 Daniel Berliner and Aseem Prakash ““Bluewashing” the Firm? Voluntary Regulations, Program Design, and Member Compliance with the United Nations Global Compact” (2014) Policy Studies Journal (forthcoming). 201 At 1. 202 At 18. 204 United Nations Global Compact “How do I prepare a COP? Advanced” <www.unglobalcompact.org>; Sustainable Business Council “Sustainable Development Reporting Guide” <www.sbc.org.nz>. 205 Sustainable Business Network “About the Sustainable Business Network” <sustainable.org.nz> p p g g 205 Sustainable Business Network “About the Sustainable Business Network” <sustainable.org.nz> 204 United Nations Global Compact “How do I prepare a COP? Advanced” <www.unglobalcompact.org>; Sustainable Business Council “Sustainable Development Reporting Guide” <www.sbc.org.nz>. 198 Deva, above n 153, at 97. 199 Ibid. 200 Daniel Berliner and Aseem Prakash ““Bluewashing” the Firm? Voluntary Regulations, Program Design, and Member Compliance with the United Nations Global Compact” (2014) Policy Studies Journal (forthcoming). 201 At 1. 202 At 17. 203 At 18. 204 United Nations Global Compact “How do I prepare a COP? Advanced” <www.unglobalcompact.org>; Sustainable Business Council “Sustainable Development Reporting Guide” <www.sbc.org.nz>. 205 Sustainable Business Network “About the Sustainable Business Network” <sustainable.org.nz> 206 Sustainable Business Council “Sustainable Development Principles” <www.sbc.org.nz>. B. How well is it working? The study found that firms who were members of the UNGC scored worse than non-members “on costly and fundamental performance dimensions, while showing improvements only in more superficial dimensions” such as having environmental policies.201 Membership of the UNGC strengthened both of those trends – more environmental concerns were reported at the same time as more superficial positives were added.202 This suggests that the subjects of the study (large publically-listed companies in the US) were using the UNGC for public relations purposes.203 C. Usefulness for New Zealand in comparison to existing initiatives There is a very low uptake of UNGC membership in New Zealand. However, this does not indicate a lack of interest in sustainability or CSR issues. New Zealand has its own voluntary initiatives that provide similar benefits to the UNGC. The SBC, like the UNGC, provides a network of like-minded businesses and requires its members to report on environmental issues (among others). Both encourage the use of the GRI’s guidelines for reporting.204 The Sustainable Business Network (“SBN”), aimed at smaller businesses in New Zealand, also provides networking and resources for members.205 The principal difference between the SBC and the UNGC is in their principles. The UNGC principles are wider than just environmental sustainability, embracing human rights and labour standards, whereas the SBC principles are much more specific in what is required of members in terms of reporting and activity.206 However, the UNGC environmental principles suggest a decision-making metric for members to follow. When making decisions that affect the environment, directors should take a precautionary approach, should take responsibility for their environmental impacts and should be looking towards using more environmentally-friendly techniques. The SBC’s principles, centred around the concept of sustainable development, are more prescriptive 27 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? when it comes to process (members must prepare policies, connect with stakeholders etc) but apart from “sustainable development” do not give guidance as to the type of approach that should be taken. In this way, the UNGC principles are more accessible. Like the SBN, the UNGC may be more appropriate to small New Zealand companies; both are significantly less costly to join for small to medium enterprises207 and are potentially more accessible. The compliance burdens are likely to be lesser as well. 207 Sustainable Business Council “Membership”< www.sbc.org.nz>; Sustainable Business Network “Join the Sustainable Business Network” <sustainable.org.nz>; United Nations Global Compact “How to participate: Business Participation” www.unglobalcompact.org. 8 Sidelle Pinto and Charl de Villiers “Do firms reduce CSR disclosures during recession?” (paper presente e 11th A-CSEAR Conference, Wollongong, NSW, December 2012) at 6. 0 Kathy Gibson and Gary O'Donovan “Corporate governance and environmental reporting: an Australian udy” (2007) 15 Corporate Governance: An International Review 944 at 947. 209 Bikram Chatterjee and others “An analysis of the qualitative characteristics of management commentary reporting by New Zealand companies” (2012) 5 Australasian Accounting, Business and Finance Journal 43 at 54. 207 Sustainable Business Council “Membership”< www.sbc.org.nz>; Sustainable Business Network “Join the Sustainable Business Network” <sustainable.org.nz>; United Nations Global Compact “How to participate: Business Participation” www.unglobalcompact.org. 208 Sidelle Pinto and Charl de Villiers “Do firms reduce CSR disclosures during recession?” (paper presented at the 11th A-CSEAR Conference, Wollongong, NSW, December 2012) at 6. 209 Bikram Chatterjee and others “An analysis of the qualitative characteristics of management commentary reporting by New Zealand companies” (2012) 5 Australasian Accounting, Business and Finance Journal 43 at 54. 210 Kathy Gibson and Gary O'Donovan “Corporate governance and environmental reporting: an Australian study” (2007) 15 Corporate Governance: An International Review 944 at 947. D. Voluntary versus mandatory environmental reporting When it comes to environmental reporting, the UNGC and the SBC both suffer from being voluntary initiatives. Voluntary environmental reporting does, of course, have its uses. It suggests that those companies are at least aware of and potentially engaging with their environmental impacts. However, in a voluntary reporting regime, companies have the capacity to choose what environmental information to report. In contrast, financial reporting is standardised to enhance accountability and comparability; it would be much more difficult to “spin” financial information without breaking the rules. Voluntary environmental disclosure would not have to be audited or assured in some way and it would not have to be reported in the same way from year to year. Voluntary environmental reporting is also influenced by the motivation of the company in reporting it. Legitimacy theory suggests that corporations seek to maintain their legitimacy in the community, to prove their place in society and to maintain the support of powerful constituencies by disclosing social and environmental information. 208 In order to retain support, companies may be tempted to report only “good” news rather than presenting a more balanced view of environmental impact. There is a tendency in voluntary corporate disclosures to report more “good” news and little if any bad news.209 Bolstering legitimacy as a motivation for voluntary environmental disclosure is supported by the tendency towards large companies operating in high-profile industries to report on environmental issues, particularly after well-publicised instances of corporate irresponsibility.210 Environmental disasters threaten the legitimacy of all the companies in that industry and so all respond with increased disclosure to regain public support. Mandatory requirements would encourage consistency of reporting, making impacts more comparable between years and across firms. Even if the legislation does not specify a 28 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? particular reporting standard, just requiring environmental impact reporting at all encourages companies to use standards such as GRI and to get their reports assured.211 Alternatively, legislation could require the use of the GRI guidelines or of other international standards such as those of the Carbon Disclosure Standards Board or of the International Standards Organisation. An argument against compulsory environmental reporting is that it could be costly for companies to monitor and collect environmental information.212 This is likely to be the case. 214 de Villiers and van Staden, above n 212. 211 Ioannis Ioannou, and George Serafeim “The Consequences of Mandatory Corporate Sustainability Reporting: Evidence from Four Countries” (2014)(11-100) Harvard Business School Research Working Paper. 212 Charl de Villiers and Chris van Staden “New Zealand shareholder attitudes towards corporate environmental disclosure” (2012) 24 Pacific Accounting Review 186 215 See for instance carboNZero Ltd which has expertise in measuring, verifying and helping to reduce G emissions of businesses. 211 Ioannis Ioannou, and George Serafeim “The Consequences of Mandatory Corporate Sustainability Reporting: Evidence from Four Countries” (2014)(11-100) Harvard Business School Research Working Paper. 212 Charl de Villiers and Chris van Staden “New Zealand shareholder attitudes towards corporate environmental disclosure” (2012) 24 Pacific Accounting Review 186. 213 Rory Sullivan and Andy Gouldson “Does voluntary carbon reporting meet investors’ needs?” (2012) 36 211 Ioannis Ioannou, and George Serafeim “The Consequences of Mandatory Corporate Sustainability Reporting: Evidence from Four Countries” (2014)(11-100) Harvard Business School Research Working Paper. 212 Charl de Villiers and Chris van Staden “New Zealand shareholder attitudes towards corporate environmental disclosure” (2012) 24 Pacific Accounting Review 186. 213 Rory Sullivan and Andy Gouldson “Does voluntary carbon reporting meet investors’ needs?” (2012) 36 Journal of Cleaner Production 60. 214 de Villiers and van Staden, above n 212. 215 See for instance carboNZero Ltd which has expertise in measuring, verifying and helping to reduce GHG emissions of businesses. y y Journal of Cleaner Production 60. Reporting: Evidence from Four Countries (2014)(11 100) Harvard Business School Research Working Paper. 212 Charl de Villiers and Chris van Staden “New Zealand shareholder attitudes towards corporate environmental disclosure” (2012) 24 Pacific Accounting Review 186. 213 Rory Sullivan and Andy Gouldson “Does voluntary carbon reporting meet investors’ needs?” (2012) 36 Journal of Cleaner Production 60. ( ) g 213 Rory Sullivan and Andy Gouldson “Does voluntary carbon reporting meet investors’ needs?” (20 Journal of Cleaner Production 60. 211 Ioannis Ioannou, and George Serafeim “The Consequences of Mandatory Corporate Sustainability Reporting: Evidence from Four Countries” (2014)(11-100) Harvard Business School Research Working D. Voluntary versus mandatory environmental reporting However, financial reporting is also costly but it is important in order to assess directorial performance and plan strategy. In the same way, environmental information should become strategically important if it is not already; even the National government has accepted that the economy must become low-carbon at some point, and so companies should be preparing for that eventuality. However, like financial reporting requirements, the environmental reporting requirements should also be tailored to firm size. SMEs should be encouraged to assess and report on environmental impact to some extent but in this paper at least, it is not argued that SMEs should have compulsory environmental reporting requirements. Listed companies should have a fuller range of reporting requirements, in line with their greater complexity and (probably) greater environmental impact. They should also have to provide this information so that investors can make investment decisions based on it if they choose. Another argument against compulsory environmental reporting is that no one would use it.213 Investors who want to know can go to the CDP to find out about the impact of some of New Zealand’s largest companies. However, not all companies report through the CDP. In addition, research has been carried out with active shareholders who were involved in the New Zealand Shareholders’ Association. The majority of participants wanted listed companies to report environmental information, even though they knew that it could be costly.214 Fewer than half of the NZX50 or the NZX100 currently report on environmental or CSR issues. The ones who already do would have a head start on the others. The other companies should not have too much trouble finding expertise to assist their reporting efforts; the benefit of New Zealand being a follower in this case is that there are a number of environmental reporting standards already prepared, and there are businesses whose expertise is in helping to measure and report on environmental impact.215 29 29 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? There are two main benefits of requiring all listed companies to report on environmental impact: balanced reporting and competition. Mandatory reporting requirements should require companies to report bad as well as good environmental news, making it more difficult for companies to spin their environmental impacts. D. Voluntary versus mandatory environmental reporting For instance, in the 2014 Fonterra Annual Report, the company reports that its farmers have excluded stock from 95% of defined waterways on their farms.216 This is undoubtedly positive but what the report does not say is how much its farmers contributed to decreased water quality in those waterways and how much stock exclusion has helped. The other benefit is that comparisons can be drawn between the environmental impact of various companies, or even just the quality of environmental reporting. This is likely to spur companies on to decrease emissions, especially as consumers and investors will be able to see the environmental reports as well. E. Summary In summary, the UNGC and SBC both include useful principles for companies to follow. The UNGC, along with the SBN may be more appropriate for SMEs than the SBC, both in terms of membership fee and accessibility of concepts. All three initiatives are positive in that they encourage companies to consider and report on environmental issues. However, being voluntary measures, the reporting carried out under those initiatives may be less balanced and less comparable than mandatory reporting. VIII. “Enlightened shareholder value” provisions in the UK Companies Act 2006 (“UK Act”) VIII. “Enlightened shareholder value” provisions in the UK Companies Act 2006 (“UK Act”) 6 Fonterra Co-Operative Group Ltd Fonterra Annual Review 2014 available at <www.fonterra.com> at 42 A. The section 172 directors' duty A. The section 172 directors' duty The UK Act augmented the existing duty of directors to promote the success of the company to include a requirement for directors to “have regard” to certain considerations. Section 172 (1) states that: A director of a company must act in a way he considers, in good faith, would be most likely to promote the success of the company for the benefit of its members as a whole, and in doing so have regard (amongst other matters) to – A director of a company must act in a way he considers, in good faith, would be most likely to promote the success of the company for the benefit of its members as a whole, and in doing so have regard (amongst other matters) to – (a) the likely consequences of any decision in the long term, (b) the interests of the company’s employees, (b) the interests of the company’s employees, (c) the need to foster the company’s business relationships with suppliers, customers and others, (d) the impact of the company’s operations on the community and the environment, (e) the desirability of the company maintaining a reputation for high standards of business conduct, and (f) the need to act fairly as between members of the company. 216 Fonterra Co-Operative Group Ltd Fonterra Annual Review 2014 available at <www.fonterra.com> at 42. 30 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? This section does not require a director to minimise the company’s impact on the environment but environmental impact must be taken into consideration. In this provision, the UK has selected an option in between the shareholder and stakeholder approach: the approach of enlightened shareholder value. This was a change from the previously adopted shareholder approach, which New Zealand still retains. The rationale behind it is that “enlightened” shareholders understand taking into account the company’s stakeholders will maximise the long term value of the company. Critics of enlightened shareholder value point out that the end result is the same as under the shareholder approach:217 the directors must act in the interests of the shareholders where there is a conflict as shareholders are the only ones with power to remove directors or enforce duties against them through derivative action. B. 217 See for instance Andrew Keay “Tackling the issue of the corporate objective: an analysis of the United Kingdom's enlightened shareholder value approach” (2007) 29 Sydney L. Rev. 577. 218 Companies Act 2006 (UK), s385(2). p ( ), ( ) 219 At s 414A(1). However, s 414A(2) exempts small companies from having to prepare a strategic repo 220 At s 414C(1) ( ) 221 At s 414C(2)(a). ( )( ) 222 At s 414C(2)(b). Companies Act 2006 (UK), s385(2). 219 At s 414A(1). However, s 414A(2) exempts small companies from having to prepare a strategic repo 220 A 414C(1) 220 At s 414C(1). A. The section 172 directors' duty Reporting on environmental impacts by quoted companies Given these critiques, the more important parts of the enlightened shareholder value provisions may well be the sections requiring quoted companies to report on their environmental impact. Quoted companies are companies whose equity share capital is listed in accordance with Part 6 of the Financial Services and Markets Act 2000 (c.8) or are officially listed in an European Economic Area State or are admitted to dealing on either the New York Stock Exchange or Nasdaq.218 The requirement for quoted companies to report on environmental impact and social and community issues has been in the UK Act since 2006. Amendments to the relevant sections were made in the Companies Act 2006 (Strategic Report and Directors’ Report) Regulations 2013 (“2013 Regulations”), which came into force on 1 October 2013. Unless otherwise stated, the sections mentioned include the amendments brought about by the 2013 Regulations. It is compulsory for the directors of all companies to prepare a strategic report.219 The purpose of this report is “to inform members of the company and help them assess how the directors have performed their duty under section 172”.220 A strategic report must contain “a fair review of the company’s business” 221 and “a description of the principal risks and uncertainties facing the company.”222 Section 414C of the UK Act sets out that: (3) The review required is a balanced and comprehensive analysis of – (a) the development and performance of the company’s business during the financial year, and (b) the position of the company’s business at the end of that year, (a) the development and performance of the company’s business during the financial year, and (b) the position of the company’s business at the end of that year, 31 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? 223 At s 414C(8). 223 At s 414C(8). p ( ), ( ) 228 At s 463. However, for the director to be liable, the director must have known the statement to be untrue or misleading or was reckless as to whether it was untrue or misleading. Likewise, to be liable for an omission, the director must have known that the omission was dishonest concealment of a material fact. 229 At s 430. 224 Large and Medium-sized Companies and Groups (Accounts and Reports) Regulations 2008, Schedule 7, at para 15(2). 225 A 17 consistent with the size and complexity of the business. (4) The review must, to the extent necessary for an understanding of the developmen performance or position of the company’s business, include – (a) analysis using financial key performance indicators, and (b) where appropriate, analysis using other key performance indicators, including information relation to environmental matters and employee matters. (b) where appropriate, analysis using other key performance indicators, including information relation to environmental matters and employee matters. (5) In subsection (4), “key performance indicators” means factors by reference to which the development, performance or position of the company’s business can be measured effectively. (6) Where a company qualifies as medium-sized in relation to the financial year…, the review for the year need not comply with the requirements of subsection (4) so far as they relate to non-financial information. (7) In the case of a quoted company the strategic report must, to the extent necessary for an understanding of the development, performance or position of the company’s business, include – (a) the main trends and factors likely to affect the future development, performance and position of the company’s business; and (b) information about – (b) information about – (i) environmental matters (including the impact of the company’s business on the environment), (ii) the company’s employees, and (ii) the company’s employees, and (iii) social, community and human rights issues, (iii) social, community and human rights issues, including information about any policies of the company in relation to those matters and the effectiveness of those policies. If the review does not contain information of each kind mentioned in paragraphs (b)(i), (ii) and (iii), it must state which of those kinds of information it does not contain. The material changes to the reporting requirements of quoted companies brought about in the 2013 Regulations include the requirement that quoted companies report on human rights issues, and also on the gender make-up of their boards and senior management.223 Most importantly, the 2013 Regulations amend the Large and Medium-sized Companies and 223 At s 414C(8). 32 32 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? At para 18. 227 Companies Act 2006 (UK), s 414D(2). 225 At para 17. 226 At para 18. consistent with the size and complexity of the business. Groups (Accounts and Reports) Regulations 2008 to require quoted companies to include in their directors’ report:224 Groups (Accounts and Reports) Regulations 2008 to require quoted companies to include in their directors’ report:224 the annual quantity of emissions in tonnes of carbon dioxide equivalent from activities for which that company is responsible including – (a) the combustion of fuel; and (b) the operation of any facility. (3) The report must state the annual quantity of emissions in tonnes of carbon dioxide equivalent resulting from the purchase of electricity, heat, steam or cooling by the company for its own use. (3) The report must state the annual quantity of emissions in tonnes of carbon dioxide equivalent resulting from the purchase of electricity, heat, steam or cooling by the company for its own use. The directors’ report of quoted companies must also state the methodologies used to calculate the annual quantity of emissions and include at least one ratio comparing annual emissions to a quantifiable factor associated with the company’s activities. 225 The report must also disclose last year’s emissions figures, including the ratio.226 The amendments make it a fineable offence to approve a strategic report which does not comply with the Act for:227 every director of the company who – (a) knew that it did not comply, or was reckless as to whether it complied, and (a) knew that it did not comply, or was reckless as to whether it complied, and (b) failed to take reasonable steps to secure compliance with those requirements or, as the case may be, to prevent the report from being approved (b) failed to take reasonable steps to secure compliance with those requirements or, as the case may be, to prevent the report from being approved The Act already contained a provision making a director of a company liable to compensate the company for any loss suffered by it as a result of any untrue or misleading statement in a report or the omission from a report of anything required to be included in it, provided the director had the requisite knowledge or recklessness.228 The reports of quoted companies are to be made available on the website of the quoted company.229 230 UK Department for Environment, Food and Rural Affairs Environmental Reporting Guidelines: Including mandatory greenhouse gas emissions reporting guidance (June 2013). 231 Samantha Fettiplace and Rebecca Addis Department for Business, Innovation and Skills: Evaluation of the Companies Act 2006, Volume 1 (Infogroup/ORC International, 2 August 2010) at 77. 232 At 77. 233 At 72 232 At 77. 233 At 72. C. Efficacy of "enlightened shareholder value" C. Efficacy of "enlightened shareholder value" C. Efficacy of "enlightened shareholder value" There is no specified standard that quoted companies have to report against in relation to their environmental impact. It is possible that the provisions could be subject to the central problem with voluntary disclosure – that is, companies choosing what to report and only reporting good news. However, the specific requirement to report on GHG emissions from year to year is one that quoted companies cannot escape. The requirement to include 33 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? environmental key performance indicators where applicable increases the reliability and usefulness of the reports. The UK Departments for Environment, Food and Rural Affairs (“Defra”) produces guidance for companies about their environmental reporting requirements. They suggest reporting on (where applicable) GHG emissions (compulsory for quoted companies), water, waste, resource efficiency and materials, emissions to land, water and air, and finally on biodiversity and ecosystem services.230 An evaluation of the UK Act was published in 2010. In it, researchers found that the majority of quoted companies surveyed (56%) were neutral when asked whether there was an increase or decrease in difficulty to comply with the requirements in the business review (requirements now in the strategic report).231 Directors of quoted companies appeared to find the reporting of environmental and social information easier than providing extra information about essential contractual arrangements and trends affecting the future development of the business. 232 Those surveyed felt that the s 172 duty had not affected the behaviour of directors.233 D. Compatibility with New Zealand law D. Compatibility with New Zealand law Like the UK before the 2006 reforms, and even arguably after them, New Zealand’s company law subscribes to the shareholder approach. The best interests of the company are usually identified with the interests of shareholders as a whole. In this way, the factors that directors must consider under s 172 of the UK Act, including consideration of the company’s impact on the environment, could fit quite easily into s 131 of the NZ Act. The requirement to report on the environmental impact and GHG emissions of listed companies could be inserted into the annual report requirements in the NZ Act. However, it is difficult at present to assess the usefulness of the enlightened shareholder value provisions in encouraging companies to lessen their environmental impact. Changes may occur in the long term but the early indications seem to be that directors and companies do not consider the changes to have had much of an impact. The critiques of the “enlightened shareholder value” approach would also suggest that the provisions will not have a significant impact on business-as-usual corporate decision making. The reporting provisions, particularly in relation to GHGs might have more of an impact as records develop and consumer pressure builds. The XRB (if empowered by the Minister) could set a standard for environmental reporting in the annual report which could make the reporting obligation more powerful. 34 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? 234 McConvill and Joy, above n 153, at 130 and 134. 235 235 At 132. 236 At 130. IX. Directors’ duty to interact with the environment in a sustainable way A. The Australian proposal McConvill and Joy also suggested that a guidance note be put in place stating that the precautionary principle must govern this provision’s interpretation so that scientific 35 35 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? uncertainty would not used as an excuse for inaction.237 The authors then went on to consider the interaction with the directors’ other duties, primarily the traditional rule that directors must seek to maximise the profits of shareholders. The authors’ view was that the new directors’ duty should take precedence over the maximisation of profit in the short-term.238 To put it another way, as long as acting in accordance with the ecological judgment rule would maximise profit in the medium or long term, the directors should not be penalised for not maximising profit in the short term. The ecological judgment rule in subsection 3 and 4 of the proposed duty would protect directors from liability for breaches of the duty to act with care and diligence and to act in good faith in the best interests of the company. The business judgment rule would also be amended to include judgments made under the new duty. The authors also recognised the possibility of environmental groups seeking injunctions against companies in anticipation of breach of the new duty, under the enhanced standing provisions in the Australian Act.239 As they did not want business to be unduly held up, environmental groups would not have standing to bring injunction actions directly in relation to this section; rather, they would have to persuade the Australian Securities and Investments Commission or Environment Australia to apply for an injunction.240 IX. Directors’ duty to interact with the environment in a sustainable way A. The Australian proposal A directors’ duty requiring interaction with the environment in a sustainable way was the suggestion of two Australian authors, McConvill and Joy. The suggested duty was this:234 (1) A director or other officer of a corporation must exercise their powers and discharge their duties to ensure that the corporation interacts with the environment in a sustainable manner. (2) For the purposes of subsection (1), a corporation will be taken to be interacting with the environment in a sustainable manner if it takes all steps reasonably practicable to reduce its ecological impact and increase its resource efficiency. (3) A director or other officer of a corporation who makes an environmental judgment is relieved from liability under subsection (1), s 180(1) and s 181(1) and their equivalent duties at common law and in equity. (4) In this section: environmental judgment means any decision to take or not take action in respect of a matter relevant to the business operations of the corporation which is rationally made to comply with subsection (1). Note: The director's or officer's judgment is a rational one unless the belief is one that no reasonable person in their position would hold. The duty was structured similarly to s 180 of the Corporations Act 2001 (Cth) (“Australian Act”) in that it had a primary obligation (to act with a reasonable degree of care and diligence), and then a provision deferring to the discretion of directors provided they comply with certain standards such as acting in good faith for a proper purpose (the business judgment rule).235 The duty would fundamentally change the relationship between companies and the environment. Subsection 2 would ameliorate the uncertainty of subsection 1 but would still encourage action on sustainability issues, while subsection 3 and 4 (the ecological judgment rule) would protect directors from prosecution for not maximising profit in the short term:236 If we keep in mind that sustainability is about balance (by maintaining production of resources for present needs, but also setting in place systems to provide for future needs), then so long as these companies can demonstrate that they have in place systems and procedures to achieve this balance, they will not fall foul of the proposed new statutory duty.. B. Application to New Zealand A similar provision could be inserted into the NZ Act, perhaps as s 131A. The focus of such a provision would, appropriately, be on encouraging sustainable development. As McConvill & Joy state:241 sustainable development inherently accommodates companies continuing to go about making money for their shareholders through production and development, so long as systems and policies are implemented which provide for improvements in resource efficiency and ecological impact over time. Our proposed statutory duty does not interfere with this balancing of considerations in any way. …A company's production and development activities will only amount to a contravention of the Corporations Act when it offends the standards of environmental protection that a reasonable person in the community (which includes the perspective of shareholders and businesspeople as well as environmentalists) would expect a company to meet. sustainable development inherently accommodates companies continuing to go about making money for their shareholders through production and development, so long as systems and policies are implemented which provide for improvements in resource efficiency and ecological impact over time. Our proposed statutory duty does not interfere with this balancing of considerations in any way. …A company's production and development activities will only amount to a contravention of the Corporations Act when it offends the standards of environmental protection that a reasonable person in the community (which includes the perspective of shareholders and businesspeople as well as environmentalists) would expect a company to meet. The duty would become stricter as standards change within the community with regard to the importance of sustainable development. There would not be the same concern about injunctions under the NZ Act as standing to apply is only conferred on a restricted class of 36 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? people. However, environmental groups should be able to notify a regulator of proposed breaches and that regulator should be able to apply for an injunction. Section 164 of the CA does not provide for a regulator to apply for an injunction; if the new duty was put in place, this should be amended. Environmental groups should also be able to apply to take a derivative action after a breach has occurred. The requirement that anyone seeking to take a derivative action must have the leave of the court would stem the floodgates potentially opened by that change. X. This paper has examined the relationship between companies and the environment in New Zealand with a view to suggesting amendments to assist New Zealand’s smooth transition towards a low-carbon and environmentally sustainable economy. It has found that directors do not have to consider the environment when taking action, nor do directors have to report on the environmental impacts of their companies. This is a stark contrast to the prescriptive rules (particularly for listed companies) when it comes to financial reporting. This lack of consideration of the environment by companies has contributed to the global environmental problems that New Zealand and the wider world face. The main drivers of global environmental change were described along with the environmental laws that New Zealand has put in place to control some of these drivers. Opportunities were then identified for corporate discretion to have a positive impact on the environment. The paper then went on to consider the voluntary environmental reporting that companies are currently carrying out. Given that less than half of listed companies report on environmental or CSR issues and for those that do, the standard of reporting varies wildly, it seems unlikely that many companies are exercising their discretion in a way that positively benefits the environment. Next the paper next examined whether companies should have a duty to consider the environment or to reduce environmental impact. Milton Friedman’s argument that the only duty of companies is to maximise profit was described and critiqued. Following Deva’s analysis, it was argued that companies do owe the moral duties that other participants in society (natural persons) owe – the duties to act within the moral and legal norms of the society. The primary moral duty is to do no harm to others. Causing environmental damage, including by emitting GHGs, causes harm to future generations, and even though it can be difficult to quantify, companies have a moral duty to minimise that harm. A moral duty to minimise environmental damage would seem to justify the imposition of some sort of legal duty for companies to protect or consider the environment. The imposition of such a duty requires trade-offs between the benefits to current generations arising from environmentally degrading activities compared to the long-run harm that is caused to the environment and future generations by the perpetuation of business-as-usual approaches. X. Three options were examined that combined some form of environmental consideration by companies with disclosure of environmental impacts. The UNGC and the New Zealand SBC 37 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? and SBN, all voluntary initiatives, were examined together to determine whether voluntary initiatives were sufficient to encourage companies to consider the environment. While it was suggested that all three had benefits to corporate decision making and corporate disclosure, voluntary disclosure was found to be inferior to mandatory environmental disclosure in terms of numbers of companies reporting and the quality and balance of the reports. The enlightened shareholder value provisions in the UK Act were considered next. While directors do have to consider the environment, and importantly, quoted companies have to report on their environmental impacts, the provisions were found to lack teeth as they do not move far enough away from the status quo where shareholders are paramount. The imposition of environmental reporting may increase the efficacy of the provisions overall as environmental issues become more important. The last option examined was the Australian proposal requiring directors to ensure that companies interact with the environment in a sustainable way. This option has the most promise in terms of encouraging directors and companies to take action to minimise environmental impact and become more sustainable. Like the enlightened shareholder value provisions, balancing of various interests would occur but with the Australian proposal, reasonable efforts would always have to be taken to reduce environmental impact. This would not be the case under the UK provisions. The Australian proposal did not set out environmental reporting requirements. However, as suggested for the UK provisions, directors of listed companies could be required to report on environmental impact in the annual report. From the above analysis, the Australian proposal combined with an environmental reporting requirement for listed companies would be the most effective of the options assessed in requiring companies to take responsibility for their environmental impacts and initiate change towards a low-carbon and environmentally sustainable economy. The safeguards put in place around the duty, such as the ecological judgment rule, would protect from prosecution directors who were making a genuine effort to minimise environmental impact. At the same time, the standard of environmental impact minimisation expected would be kept at the level of reasonableness as assessed with reference to societal expectations. Word count (excluding referencing, bibliography and title page): 14, 994. X. Amending the standing requirements to take a derivative action to include environmental groups would also act as an encouragement for companies to take action, while retaining the leave provision would mean that cases were only taken where they had real merit. Allowing a regulator, such as the Financial Markets Authority or potentially the Ministry for the Environment to apply for an injunction would also be a positive step in making sure that the provisions were taken seriously. However, if the government is unwilling to require directors to either take into account environmental impacts or to act in such a way as to ensure companies interact with the environment in a sustainable way, the government should still put in place environmental 38 38 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? reporting requirements at least for listed companies. This would mean that when society finally demands sustainability on the part of its companies, companies actually know what their impacts are in order to reduce them. Encouraging networks such as the SBC, SBN and UNGC would also be beneficial, particularly for smaller companies. Word count (excluding referencing, bibliography and title page): 14, 994. 39 39 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? XI. Bibliography A. Cases 1. New Zealand Nicholson v Permakraft (NZ) Ltd [1985] 1 NZLR 242 (CA). 2. Canada Peoples Department Stores Inc. (Trustee of) v Wise [2004] 3 SCR 461. 3. United Kingdom Donoghue v Stevenson [1932] AC 562 (HL). Fisheries Act 1996 Fisheries Act 1996 Financial Markets Conduct Act 2013. Financial Reporting Act 2013. Resource Management Act 1991. State-Owned Enterprises Act 1986. Waste Minimisation Act 2008. Wildlife Act 1953. A. Cases Biosecurity Act 1993. Climate Change Response (Emissions Trading) Amendment Act 2008. Climate Change Response (Emissions Trading and Other Matters) Amendment Act 2012. Companies Act 1993. Climate Change Response (Emissions Trading and Other Matters) Amendment Act 2012. Companies Act 1993. Companies Act 1993. Conservation Act 1987. C. International Materials Rio Declaration on Environment and Development A/CONF.151/26 (1992). United Nations Sustainable Development Agenda 21. 2. Australia Corporations Act 2001. 3. United Kingdom 40 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? Companies Act 2006. Companies Act 2006 (Strategic Report and Directors’ Report) Regulations 2013. Large and Medium-sized Companies and Groups (Accounts and Reports) Regulations 2008. 4. United States of America Sarbanes-Oxley Act of 2002, Pub. L. No. 107-204, 116 Stat. 745. Sarbanes-Oxley Act of 2002, Pub. L. No. 107-204, 116 Stat. 745. D. Books and Chapters in Books Alastair Cameron “Corporate and Commercial Issues” in Alastair Cameron (ed) Climate Change Law and Policy in New Zealand (LexisNexis NZ Ltd, Wellington, 2011) 393. Alastair Cameron "New Zealand Emissions Trading Scheme" in Alastair Cameron (ed) Climate Change Law and Policy in New Zealand (LexisNexis NZ Ltd, Wellington, 2011) 239. Jonathan Boston "The Nature of the Problem and the Implications for New Zealand" in Alastair Cameron (ed) Climate Change Law and Policy in New Zealand (LexisNexis NZ Ltd, Wellington, 2011) 87. Brookers Company Law (online looseleaf ed, Thomson Reuters). Surya Deva Regulating corporate human rights violations: humanizing business (Routledge, London & New York, 2012). Rashid Hassan, Robert Scholes and Neville Ash (eds) Ecosystems and Human Well-being: Current State and Trends, Volume 1 (Millenium Ecosystem Assessment Board/Island Press, Washington, 2005). Nolan, Derek (ed) Environmental & Resource Management Law (4th ed, LexisNexis, Wellington 2011). David Norton and Nick Reid Nature and Farming: sustaining native biodiversity in agricultural systems (CSIRO Publishing, Collingwood, Victoria, 2013). James Rachels The end of life: euthanasia and morality (Oxford University Press, Oxford; New York; London, 1986). 41 41 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? Vernon Rive “International Framework” in Alastair Cameron (ed) Climate Change Law and Policy in New Zealand (LexisNexis NZ Ltd, Wellington, 2011) 49. Vernon Rive “International Framework” in Alastair Cameron (ed) Climate Change Law and Policy in New Zealand (LexisNexis NZ Ltd, Wellington, 2011) 49. Peter Watts Directors' Powers and Duties (LexisNexis, Wellington, 2009). Peter Wilson “The Economics of Emissions Trading” in Alastair Cameron (ed) Climate Change Law and Policy in New Zealand (LexisNexis NZ Ltd, Wellington, 2011) 127. Peter Wilson “The Economics of Emissions Trading” in Alastair Cameron (ed) Climate Change Law and Policy in New Zealand (LexisNexis NZ Ltd, Wellington, 2011) 127. E. Journal Articles Afshin Akhtarkhavari “The Global Compact, Environmental Principles, and Change in International Environmental Politics” (2009) 38 Denv. J. Int'l L. & Pol'y 277. Afshin Akhtarkhavari “The Global Compact, Environmental Principles, and Change in International Environmental Politics” (2009) 38 Denv. J. Int'l L. & Pol'y 277. Jan Bebbington, Colin Higgins and Bob Frame “Initiating sustainable development reporting: evidence from New Zealand” (2009) 22 Accounting, Auditing & Accountability Journal 588. Jan Bebbington, Colin Higgins and Bob Frame “Initiating sustainable development reporting: evidence from New Zealand” (2009) 22 Accounting, Auditing & Accountability Journal 588. Jan Bebbington, Colin Higgins and Bob Frame “Initiating sustainable development reporting: evidence from New Zealand” (2009) 22 Accounting, Auditing & Accountability Journal 588. Daniel Berliner and Aseem Prakash ““Bluewashing” the Firm? Voluntary Regulations, Program Design, and Member Compliance with the United Nations Global Compact” (2014) Daniel Berliner and Aseem Prakash ““Bluewashing” the Firm? Voluntary Regulations, Program Design, and Member Compliance with the United Nations Global Compact” (2014) Policy Studies Journal. Daniel Berliner and Aseem Prakash ““Bluewashing” the Firm? Voluntary Regulations, Program Design, and Member Compliance with the United Nations Global Compact” (2014) Policy Studies Journal. Program Design, and Member Compliance with the United Nations Global Compact” (2014) Policy Studies Journal. Jonathan Boston and Frieder Lempp "Climate change: Explaining and solving the mismatch between scientific inertia and political inertia" (2011) 24 AAAJ 1001. Dilek Cetindamar and Kristoffer Husoy "Corporate Social Responsibility Practices and Environmentally Responsible Behavior: The Case of United Nations Global Compact" (2007) 76 Journal of Business Ethics 163. Bikram Chatterjee and others “An analysis of the qualitative characteristics of management commentary reporting by New Zealand companies” (2012) 5 Australasian Accounting, Business and Finance Journal 43. Robert Costanza and others “The value of the world's ecosystem services and natural capital” (1997) 387 Nature 253. Charl de Villiers and Chris van Staden “New Zealand shareholder attitudes towards corporate environmental disclosure” (2012) 24 Pacific Accounting Review 186. Charl de Villiers and Chris van Staden “New Zealand shareholder attitudes towards corporate environmental disclosure” (2012) 24 Pacific Accounting Review 186. Charl de Villiers and Chris van Staden “New Zealand shareholder attitudes towards corporate environmental disclosure” (2012) 24 Pacific Accounting Review 186. Milton Friedman “The social responsibility of business is to increase its profits” The New York Times Magazine 13 September 1970. Milton Friedman “The social responsibility of business is to increase its profits” The New York Times Magazine 13 September 1970. E. Journal Articles Milton Friedman “The social responsibility of business is to increase its profits” The New York Times Magazine 13 September 1970. Kathy Gibson and Gary O'Donovan “Corporate governance and environmental reporting: an Australian study” (2007) 15 Corporate Governance: An International Review 944. Kathy Gibson and Gary O'Donovan “Corporate governance and environmental reporting: an Australian study” (2007) 15 Corporate Governance: An International Review 944. Rob Gray “Does sustainability reporting improve corporate behaviour?: Wrong question? Right time?” (2006) 36(sup1) Accounting and Business Research 65. Rob Gray “Does sustainability reporting improve corporate behaviour?: Wrong question? Right time?” (2006) 36(sup1) Accounting and Business Research 65. 42 42 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? Ioannis Ioannou and George Serafeim “The Consequences of Mandatory Corporate Sustainability Reporting: Evidence from Four Countries” (2014)(11-100) Harvard Business School Research Working Paper. Ioannis Ioannou and George Serafeim “The Consequences of Mandatory Corporate Sustainability Reporting: Evidence from Four Countries” (2014)(11-100) Harvard Business School Research Working Paper. Ioannis Ioannou and George Serafeim “The Consequences of Mandatory Corporate Sustainability Reporting: Evidence from Four Countries” (2014)(11-100) Harvard Business School Research Working Paper. Jason C. Jones “Environmental Disclosure: Toward an Investor Based Corporate Environmentalism Norm” (2010) 20 BU Pub. Int. LJ 207. Andrew Keay “Tackling the issue of the corporate objective: an analysis of the United Kingdom's enlightened shareholder value approach” (2007) 29 Sydney L. Rev. 577. James McConvill and Martin Joy "The interaction of directors' duties and sustainable development in Australia: setting off on the uncharted road" (2003) 27 Melb.U.L.Rev. 116 Markus J. Milne, Helen Tregidga and Sara Walton “Words not actions! The ideological role of sustainable development reporting” (2009) 22 Accounting, Auditing & Accountability Journal 1211. Jessika Luth Richter and Lizzie Chambers "Reflections and Outlook for the New Zealand ETS: must uncertain times mean uncertain measures?" (2014) 10 Policy Quarterly 57. Osvaldo Sala and others “Global biodiversity scenarios for the year 2100” (2000) 287 Science 1770. Rory Sullivan and Andy Gouldson “Does voluntary carbon reporting meet investors’ needs?” (2012) 36 Journal of Cleaner Production 60. F. Parliamentary and government materials Cabinet Minute “Emissions Trading Scheme Review 2012: Final Decisions on Amendments to the Climate Change Response Act 2002” (2 July 2012) CAB Min (12) 23/10. Cabinet Minute “Emissions Trading Scheme Review 2012: Final Decisions on Amendments to the Climate Change Response Act 2002” (2 July 2012) CAB Min (12) 23/10. Office of the Minister for Climate Change Issues "Emissions Trading Scheme Review 2012 – final decisions on amendments to the Climate Change Response Act 2002". Office of the Minister for Climate Change Issues "Emissions Trading Scheme Review 2012 – final decisions on amendments to the Climate Change Response Act 2002". "The Climate Change Response (2050 Emissions Target) Notice 2011" (31 March 2011) 41 New Zealand Gazette 987. G. Reports CDP Australia & NZ CDP 2014 ASX 200 Climate Leadership Awards (Carbon Disclosure Project, Australia, 2014). CDP Australia & NZ CDP 2014 ASX 200 Climate Leadership Awards (Carbon Disclosure Project, Australia, 2014). CDP Australia and New Zealand Climate Change Report 2013 (Carbon Disclosure Project, Project, Australia, 2014). CDP Australia and New Zealand Climate Change Report 2013 (Carbon Disclosure Project, December 2013). CDP Australia and New Zealand Climate Change Report 2013 (Carbon Disclosure Project, December 2013). CDP Australia and New Zealand Climate Change Report 2013 (Carbon Disclosure Project, December 2013). 43 43 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? Tim Herzog, Jonathan Pershing, and Kevin A. Baumert Navigating the Numbers: Greenhouse Gas Data and International Climate Policy (World Resources Institute, 2005). Richard Holme and Phil Watts Corporate social responsibility: making good business sense (World Business Council on Sustainable Development, January 2000). International Energy Agency World Energy Outlook 2012: Executive Summary (OECD/IEA, France, 2012). KPMG International The KPMG Survey of Corporate Responsibility Reporting 2013 (KPMG International, 2013). Millenium Ecosystem Assessment Ecosystems and Human Well-being: Synthesis (Island Press, Washington, 2005). Ministry for the Environment, Environmental Snapshot: Legally protected conservation land in New Zealand (Ministry for the Environment, April 2010). Ministry for the Environment Valuing Our Clean Green Image (Ministry for the Environment, August 2001). B. Mullan, D. Wratt, S. Dean, M. Hollis, S. Allan, T. Williams, G. Kenny and MfE Climate Change Effects and Impacts Assessment: A Guidance Manual for Local Government in New Zealand (2nd ed, Ministry for the Environment, Wellington 2008). H. Conference Papers Kyleisha Foote & Mike Joy "The true cost of milk: Environmental deterioration vs. profit in the New Zealand dairy industry" (paper presented at the 2014 New Zealand Agricultural & Resource Economics Society (Inc.), Nelson, August 2014). Sidelle Pinto and Charl de Villiers “Do firms reduce CSR disclosures during recession?” (paper presented at the 11th A-CSEAR Conference, Wollongong, NSW, December 2012). I. Internet Resources Carbon Disclosure Project website <www.cdp.net>. Clark, Gordon and Knight, Eric R "Institutional investors, the political economy of corporate disclosure, and the market for corporate environmental and social responsibility: implications from the UK Companies Act (2006)" (2008) Social Science Research Network www.ssrn.com. Companies Office website www.business.govt.nz. 44 Being a Tidy Kiwi Company: should New Zealand require its companies to report on their environmental impacts? Fonterra Co-Operative Group Ltd Fonterra Annual Review 2014 available at <www.fonterra.com> Global Reporting Initiative website <www.globalreporting.org>. Global Reporting Initiative – Sustainability Disclosure Database <http://database.globalreporting.org/>. Grant Thornton "Corporate social responsibility: beyond financials" (2014) www.internationalbusinessreport.com. Ministry for the Environment website www.mfe.govt.nz. Ministry of Foreign Affairs & Trade website http://mfat.govt.nz ONE News "John Key defends Kyoto decision" (12 November 2012 ) http://tvnz.co.nz. Sustainable Business Council website <www.sbc.org.nz>. Sustainable Business Network <sustainable.org.nz>. United Nations Global Compact website <www.unglobalcompact.org>. United Nations Global Compact website <www.unglobalcompact.org>. United Nations Global Compact website <www.unglobalcompact.org>. J. Other Materials ASX Corporate Governance Council Corporate Governance Principles and Recommendations (3rd ed, 2014). Department for Environment, Food and Rural Affairs (UK) Environmental Reporting Guidelines: Including mandatory greenhouse gas emissions reporting guidance (June 2013). Ministry of Fisheries Sustainable New Zealand Seafood: Orange Roughy (Ministry of Fisheries, October 2011). NZX Limited Main Board/Debt Market Listing Rules (NZX Limited, 30 October 2013 NZX Limited Main Board/Debt Market Listing Rules (NZX Limited, 30 October 2013). Nick Smith "RMA reform agenda outlined" (press release, 21 January 2015). Nick Smith "RMA reform agenda outlined" (press release, 21 January 2015). Statistics New Zealand New Zealand in profile: An overview of New Zealand's people, economy and environment (Statistics New Zealand, February 2014). United Nations Global Compact Guide for responsible corporate engagement in climate policy: a caring for climate report (UNGC, 2013). XRB, Standard XRB A1. 45
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Visual Attentional Training Improves Reading Capabilities in Children with Dyslexia: An Eye Tracker Study During a Reading Task
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To cite this version: Simona Caldani, Christophe-Loïc Gerard, Hugo Peyre, Maria Pia Bucci. Visual Attentional Training Improves Reading Capabilities in Children with Dyslexia: An Eye Tracker Study During a Reading Task. Brain Sciences, 2020, 10 (8), pp.558. ￿10.3390/brainsci10080558￿. ￿hal-03148895￿ Visual Attentional Training Improves Reading Capabilities in Children with Dyslexia: An Eye Tracker Study During a Reading Task Simona Caldani, Christophe-Loïc Gerard, Hugo Peyre, Maria Pia Bucci Visual Attentional Training Improves Reading Capabilities in Children with Dyslexia: An Eye Tracker Study During a Reading Task Simona Caldani, Christophe-Loïc Gerard, Hugo Peyre, Maria Pia Bucci Received: 24 July 2020; Accepted: 12 August 2020; Published: 15 August 2020 Abstract: Dyslexia is a specific disorder in reading abilities. The aim of this study was to explore whether a short visual attentional training could improve reading capabilities in children with reading disorders by changing their oculomotor characteristics. Two groups (G1 and G2) of 25 children with reading disabilities and who are matched in IQ (intelligence quotient), sex, and age participated in the study. The allocation of a subject to a specific group (G1 = experimental group; G2 = control group) was generated in an unpredictable random sequence. The reading task was recorded twice for G1, i.e., before (T1) and after (T2) 10 min of visual attentional training. Training consisted of oculomotor tasks (saccades and pursuits movements) and searching tasks (three different exercises). For G2, the two reading tasks at T1 and T2 were done at an interval of 10 min instead. We found that at T1, oculomotor performances during reading were statistically similar for both groups of children with reading disabilities (G1 and G2). At T2, the group G1 only improved oculomotor capabilities significantly during reading; in particular, children read faster, and their fixation time was shortest. We conclude that short visual attentional training could improve the cortical mechanisms responsible for attention and reading capabilities. Further studies on a larger number of dyslexic children will be necessary in order to explore the effects of different training types on the visual attentional span given its important role on the orienting and focusing visuospatial attention and on the oculomotor performance in children with dyslexia. Keywords: eye movements; dyslexia; children; reading disabilities; visual attentional training Visual Attentional Training Improves Reading Capabilities in Children with Dyslexia: An Eye Tracker Study During a Reading Task Simona Caldani 1,2,*, Christophe-Loïc Gerard 3, Hugo Peyre 3,4 and Maria Pia Bucci 1,2 1 UMR 7114 MoDyCo, CNRS-Université Paris Nanterre, 92000 Nanterre, France; mariapia.bucci@gmail.com 2 EFEE—Centre D’Exploration Fonctionnelle de L’Équilibre Chez L’Enfant, Robert Debré Hospital, 75019 Paris, France 3 Child and Adolescent Psychiatry Department Robert Debré Hospital 75019 Paris France; Simona Caldani 1,2,*, Christophe-Loïc Gerard 3, Hugo Peyre 3,4 and Maria Pia Bucci 1,2 1 UMR 7114 MoDyCo, CNRS-Université Paris Nanterre, 92000 Nanterre, France; mariapia.bucci@gm 2 EFEE—Centre D’Exploration Fonctionnelle de L’Équilibre Chez L’Enfant, Robert Debré Hospital, 75019 Paris, France 3 Child and Adolescent Psychiatry Department, Robert Debré Hospital, 75019 Paris, France; christophe.loic@gmail.com (C.-L.G.); peyrehugo@yahoo.fr (H.P.) 4 Université de Paris, 75000 Paris, France * Correspondence: simona.caldani@gmail.com Simona Caldani 1,2,*, Christophe-Loïc Gerard 3, Hugo Peyre 3,4 and Maria Pia Bucci 1,2 1 UMR 7114 MoDyCo, CNRS-Université Paris Nanterre, 92000 Nanterre, France; mariapia.bucci@gmail.com 2 EFEE—Centre D’Exploration Fonctionnelle de L’Équilibre Chez L’Enfant, Robert Debré Hospital, 75019 Paris, France 3 Child and Adolescent Psychiatry Department, Robert Debré Hospital, 75019 Paris, France; christophe.loic@gmail.com (C.-L.G.); peyrehugo@yahoo.fr (H.P.) 4 Université de Paris, 75000 Paris, France * Correspondence: simona.caldani@gmail.com Simona Caldani , ,*, Christophe-Loïc Gerard , Hugo Peyre , and Maria Pia Bucci , 1 UMR 7114 MoDyCo, CNRS-Université Paris Nanterre, 92000 Nanterre, France; mariapia.bucci@gmail.com 2 EFEE—Centre D’Exploration Fonctionnelle de L’Équilibre Chez L’Enfant, Robert Debré Hospital, * Correspondence: simona.caldani@gmail.com * Correspondence: simona.caldani@gmail.com HAL Id: hal-03148895 https://hal.parisnanterre.fr/hal-03148895v1 Submitted on 22 Feb 2021 L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. brain sciences brain sciences 1. Introduction Dyslexia is a disorder reported in 5–10% of school-aged children [1]. Given the heterogeneity of this disorder in the literature there are still different theories that have tried to explain its etiology [2]. Actually, it is known that genetical investigations indicate a family risk, and the presence of a phonological impairment in dyslexia could be considered the most robust hypothesis suggesting that dyslexic children showed difficulties to read because they fail to acquire the skill of separating the sounds in a word in order to match them to their visual letter counterparts [2]. However, other hypotheses have been put forward. For instance, several studies reported deficits in auditory capabilities [3], as well as in visual perception and oculomotor performances [4,5]. Nicolson and Fawcett [6] advanced the hypothesis of a cerebellar impairment that leads to poor automaticity and motor control in children with dyslexia. Facoetti et al. [7] reported also in children with dyslexia a specific disability in orienting as well www.mdpi.com/journal/brainsci Brain Sci. 2020, 10, 558; doi:10.3390/brainsci10080558 www.mdpi.com/journal/brainsci 2 of 13 Brain Sci. 2020, 10, 558 as in sustained focusing visuospatial attention. Our group further explored oculomotor capabilities in dyslexic children and suggested a deficit in visual attentional processing in relation to the immaturity of cortical structures responsible for saccades triggering [8–10]. Reading, in fact, corresponds to a complex cognitive process during which several mechanisms are involved: visual perception, eye movements such as saccades and fixations, and semantic and linguistic abilities; consequently, a deficit in one of these different components could cause impairment in reading acquisition. Previous studies from our group [11] and other groups [12,13] reported a longer duration of fixation in children starting to read, explained by the immaturity of cortical structures responsible for eye fixation [14]. During the normal development of reading skills, children learn to read rapidly by having shorter durations of fixations, larger prosaccades, and fewer regressions; in other words, eye movement patterns become similar to those observed in adults. In contrast, in children with dyslexia this oculomotor pattern is not observed; indeed, it is well documented that children with dyslexia have abnormal oculomotor patterns during reading, e.g., a slower reading speed, longer duration of fixations, frequent and smaller prosaccades, and several regressions [15]. Interestingly, such characteristics have been reported in children with dyslexia of different countries speaking different languages (Greek speaking [16]; English speaking [17]; Italian speaking [18], and German speaking [19]). 1. Introduction However, the hypothesis of an abnormal oculomotor pattern in dyslexia and related visual deficits is not shared by other researchers; for instance, the authors in [20] showed that visual deficit impairments could be causal in dyslexia, and other researchers advanced the hypothesis that poor oculomotor behavior is a consequence and not the cause of dyslexia [21]. This question is still under debate. One of the most important objectives of research conducted on children with dyslexia is to develop training types able to improve reading skills, particularly reading speed—even if it is influenced by the type of language (more or less transparent, see previously cited studies)—as it is an important parameter for dyslexic children during school activities, given that if children need a longer time to read they cannot do the other school exercises as nondyslexic children do. Although linguistic training is the most studied [22], research has also been carried out on nonlinguistic training types. Firstly, Solan et al. [23], in order to study some of the visual processes of reading disability, compared two types of training (eye movement and comprehension training for 12 one-hour sessions) in two groups of 15 children of 11 years old with dyslexia. For the eye movement training, the perceptual accuracy/visual efficiency method was used, while for the comprehension training the child must correct missing words in a sentence. They found that the number of fixations as well as the number of regressive saccades and comprehension were both improved by eye movement training; similar results were obtained by comprehension training, supporting the notion of a cognitive link between visual attention, eye movement’s performance, and reading comprehension. These findings support the existence of a cognitive relationship among visual attention, eye movements, and reading comprehension. Meng et al. [24] reported reading enhancement in Chinese-speaking children with dyslexia after ten sessions within four weeks of visual perceptual training (texture discrimination tasks lasting about 50 min/session); interestingly, such improvement was still observed two months later. These authors advanced the hypothesis that temporal processing and spatial attentional capabilities leading to enlarging the visual span could be the possible cause of the training effect. This study suggested that, at least in Chinese readers, visual perceptual processing and reading ability could share a similar network. Several studies conducted in children with dyslexia have reported an improvement of reading performance by decreasing the crowding phenomenon (i.e., increasing letter spacing [25–27]). 1. Introduction It should be noted, however, that for most of these studies the number of children with dyslexia was small, and no eye movement recording during reading was performed. Our group recorded eye movements during reading and confirmed in French children with dyslexia the beneficial effect of large letter spacing between words for reading [28]. Recently, we showed also that a computer-based oculomotor training (15 min per day for five/seven days per week for 8 weeks) in a small group of 16 Italian 3 of 13 Brain Sci. 2020, 10, 558 children with dyslexia could improve reading abilities by shortening the reading time and the duration of fixation objectively measured (by an eye tracker), perhaps via visual attentional capabilities [29]. More recently, Cancer et al. [30] compared in a small group of dyslexic children (n = 12) the effect of rhythmic reading training (RRT) on reading speed and accuracy with respect to those of two training types already validated (i.e., Bakker’s visual hemisphere-specific stimulation and the action video game training). Both training types were administrated for 13 h over nine days. The authors reported that RRT improved more significantly the pseudoword reading speed, and the other training increased general reading accuracy. Authors suggested that these different results could be due to different cognitive mechanisms trained; in other words, the RTT could affect phonological awareness while the other training could have an effect on rapid automatized naming. Based on these results we could make the hypothesis that specific training types could be developed for different types of dyslexia. This hypothesis, however, needs to be tested on a large population with dyslexia. Peters and colleagues [31] made a systematic review on the effect of visual attentional training on reading abilities in children with dyslexia aged 5–15 years old. These authors selected eighteen studies and analyzed three types of visual attentional interventions: action video games, reading acceleration, and visual perceptual training. Their findings showed that action video games improved speed reading and fluency, while reading acceleration programs increased accuracy, and speed reading and visual perceptual training benefited reading fluency and comprehension. Interestingly, these interventions can improve reading capabilities for at least two months after training. It should be noted, however, that other researchers [32] did not confirm these results. 1. Introduction It is important also to point out that no study recorded eye movement behavior to confirm or not the eventual benefit of interventions, with the exception of one study in which a small group of children were tested (nine children only) [33]. Based on these findings, the aim of the present study is to measure by an eye tracker the effect of a short visual attentional training on the reading skills in French children with reading disorders. Eye movement recording is an objective tool that allow us to better understand the eventual changes in oculomotor patterns in children with dyslexia after training. Our final purpose is to develop a new functional training program for this kind of children. 2.1. Subjects Fifty children with reading disorders (from 7.8 to 12 years old) were recruited from the Robert Debré Pediatric Hospital. The children in the study underwent a complete evaluation (see our previous studies [8–15]). For each child, the L2MA (Langage Oral Écrit Mémoire Attention) [34] was used to measure text comprehension and the ability to read words and pseudowords. The child was included in the study if (i) their L2MA score was more than two standard deviations from the mean (all children included had dyslexia); (ii) the intelligent quotient (IQ, evaluated using the) was in normal range (between 85 and 115); (iii) they had normal visual acuity at near vision (both eyes ≥10/10); (iv) any hyperactivity deficit was excluded, using the ADHD (Attention-deficit/hyperactivity disorder) Rating Scale (ADHD-RS) parental report. It should be noted also that no treatment was given to the children, and all of them were naive of therapeutic intervention. For each child we also evaluated the reading age by using the ELFE test (Évaluation de la Lecture en FluencE) (www.cognisciences.com, Grenoble, France) and the visual attentional (VA) span test [35]. For more details, the ELFE test is used to measure the reading age of children, and it is widely used in French laboratories/clinicians to evaluate the reading age of children. Each child was allocated to a specific group (G1 = experimental group; G2 = control group) using an unpredictable random sequence; the group G1 has only benefited from visual attentional rehabilitation. It should be noted that the children were unaware of the experimental manipulations, and only parents were informed about the goal of the study. The investigation adhered to the 4 of 13 Brain Sci. 2020, 10, 558 principles of the Declaration of Helsinki and was accepted by the Institutional Human Experimentation Committee of CPP (Comité de protection des personnes) Ile de France I (INSERM CEEI-IRB, N◦16-290, Hotel-Dieu Hospital, Paris). p Below are details for the ELFE test and the VA (visual attention) span test. The ELFE test consisted of two texts, i.e., “Le Geant Egoiste” and “Monsieur Petit”. The child was invited to read aloud one text during 1 min, and the examiner counted the number of words read. 2.1. Subjects It should be noted that the two texts are similar and comparable for their difficulty and orthography; the number of words with high and low frequency as well as the number of longer and shorter words were similar, and consequently the two texts can be used for measuring reading age before and after training without any risk of learning effect. The VA span test consisted of 20 trials, in which the child was required to orally report a string of 5 letters that was briefly presented at the center of the monitor screen. At the beginning of each trial, a central fixation point was presented for 1000 ms followed by a blank screen for 500 ms. A letter string was then presented at the center of the display for 200 ms. The child had to report verbally all the letters immediately after they disappeared. After having written their response, the examiner pressed a button to start the next trial. At the end the examiner counted the number of letters accurately reported across the trials. Clinicians in France frequently use this test. 2.2. Reading Task The text was presented on a 22-inch LCD (liquid-crystal display) screen with “full HD (High-Definition) resolution” (image size of 1920 × 1080 pixels). The child was asked to read aloud a text of four lines from a children’s book (extract from Jojo Lapin Fait des Farces, Gnid Bulton, Hachette). The paragraph contained 40 words and 174 characters. The text was 29◦wide and 6.4◦high; mean character width was 0.5◦, and the text was written in black Courier font on a white background. This reading task is showed in Appendix A (Texts 1 and 2, see Figures A1 and A2); it should be noted that only the length, subject, and writing style were balanced. Eye movements during the reading task were recorded two times at T1 and T2, i.e., before and after, respectively, 10 min of visual attentional training for the group G1 (experimental group) and also before and after 10 min for the group G2 (control group). The order of the text (Texts 1 and 2) presented in T1 and T2 was counterbalanced. It should be noted that the child was instructed to read the text without asking for comprehension. 2.2.1. Visual Attentional Training Visual attentional training consisted of both oculomotor exercises without recording eye movements (pursuits, saccades) and three searching tasks by using Metrisquare© Lebe Business Centers Sittard, Sittard, Nederland. It should be noted that the child received specific instructions for each test (see below in the “Oculomotor Task” and “Searching Task” sections). 2.2.3. Searching Task 2.2.3. Searching Task Th diff Three different types of searching exercises were used. The child had to search for some small objects and to remove them with a pencil following the instructions of the experimenter. The objects were presented on a tablet that was connected to a PC (Metrisquare©), and the pencil was also connected with this PC, allowing for an objective measurement of the time needed to execute the exercise, the errors, and the omission of each exercise (for more details, see Chatard et al. [36]). The three exercises are referred to as “house”, “cat”, and “space rockets”. Three different types of searching exercises were used. The child had to search for some small objects and to remove them with a pencil following the instructions of the experimenter. The objects were presented on a tablet that was connected to a PC (Metrisquare©), and the pencil was also connected with this PC, allowing for an objective measurement of the time needed to execute the exercise, the errors, and the omission of each exercise (for more details, see Chatard et al. [36]). The three exercises are referred to as “house”, “cat”, and “space rockets”. In the house exercise 36 colored houses on a white background of (2 × 2 cm) were presented In the house exercise, 36 colored houses on a white background of (2 × 2 cm) were presented, among which 24 houses are on fire. The child was asked to remove the houses that are not on fire (see Figure 1A). In the cat exercise, 24 black heads of cats on a white background were presented together with 24 black stars and 24 black trees (0.5 × 1 cm). The child was asked to remove all the heads of the cats (see Figure 1B). In the space rockets exercise, 104 black space rockets having different characteristics were presented on a white background (2 × 1 cm). The child was requested to remove 16 rockets that match the model (see Figure 1C). In the house exercise, 36 colored houses on a white background of (2 × 2 cm) were presented, among which 24 houses are on fire. The child was asked to remove the houses that are not on fire (see Figure 1A). In the cat exercise, 24 black heads of cats on a white background were presented together with 24 black stars and 24 black trees (0.5 × 1 cm). 2.2.2. Oculomotor Task Two oculomotor tasks were used: horizontal visually-guided saccades and horizontal pursuits presented on the PC (personal computer) that was used for the reading task. For horizontal visually-guided saccades, the stimulus (both the central and eccentric targets) was a white filled circle subtending a visual angle of 0.5◦. After a variable fixation period ranging between 2000 and 3500 ms, the central target disappeared, and a target at the left or at the right side of the screen simultaneously appeared for 1000 ms. The central fixation target then reappeared, signaling the beginning of the next trial. Each child performed two blocks of 30 visually-guided saccades randomly presented to the left and to the right side of different amplitudes (5◦, 10◦, 15◦, and 20◦). The child was instructed to look at the target as accurately and as rapidly as possible. The pursuit task requires the child to follow a slowly moving visual target displayed on the PC. The target velocity was of 15◦/s. The target (a white circle of 0.5◦) was initially placed in the central position (0◦) and then moved horizontally to one side until it reached a ±20◦location, where it reversed 5 of 13 5 of 14 Brain Sci. 2020, 10, 558 Brain Sci. 2020, 10, x FO abruptly and moved to the opposite side. A total of nine cycles were run. Children were instructed to keep their eyes on the target, wherever it moved. Children had to perform the same test four times. The duration of the pursuit task was 2 min. reversed abruptly and moved to the opposite side. A total of nine cycles were run. Children were instructed to keep their eyes on the target, wherever it moved. Children had to perform the same test four times. The duration of the pursuit task was 2 min. 2.2.3. Searching Task 2.2.3. Searching Task Th diff The child was asked to remove all the heads of the cats (see Figure 1B). In the space rockets exercise, 104 black space rockets having different characteristics were presented on a white background (2 × 1 cm). The child was requested to remove 16 rockets that match the model (see Figure 1C). Figure 1. Visual attentional exercises by Metrisquare©: house (A), cats (B), and space rockets (C). h d f h h bl f d d h Figure 1. Visual attentional exercises by Metrisquare©: house (A), cats (B), and space rockets (C). The duration of three searching exercises was variable (from 5 to 7 min), depending on the tim Figure 1. Visual attentional exercises by Metrisquare©: house (A), cats (B), and space rockets (C). Figure 1. Visual attentional exercises by Metrisquare©: house (A), cats (B), and space rockets (C). Figure 1. Visual attentional exercises by Metrisquare©: house (A), cats (B), and space rockets (C). Figure 1. Visual attentional exercises by Metrisquare©: house (A), cats (B), and space rockets (C). The duration of three searching exercises was variable (from 5 to 7 min), depending on the time needed for the child to perform the tasks. Any feedback on the performance was given to the child after doing the Metrisquare task The duration of three searching exercises was variable (from 5 to 7 min), depending on the time needed for the child to perform the tasks. Any feedback on the performance was given to the child after doing the Metrisquare task. Eye Movement Recording During the execution of reading task, eye movements were recorded using an Eye Brain T2® (SuriCog, Paris, France) head-mounted eye tracker. This eye tracker is a medical EC (European Commission) certified device. The accuracy of this system is 0.25◦, and its recording frequency reaches 300 Hz. This device can record the position of the eyes horizontally and vertically, independently and simultaneously for each eye. Calibration is done before eye movement recording. The calibration consists of a succession of red dots (diameter of 0.5◦), presented on a flat PC screen of dimensions 512 × 288 mm, corresponding to the nominal diagonal size of 22 inches. During this procedure, we asked the children to look a grid of 13 points mapping the screen at a distance of 60 cm. Calibration is calculated for a 250 ms fixation period for each point. There is no obstruction of the visual field during registration with the recording system, and the calibrated zone covers a visual angle of ±22◦[35]. After the calibration procedure, the reading task was explained to the child. Duration of each task varied accordingly to the specific child’s reading speed. 2.5. Statistical Analysis Statistical analysis using the GLM (general linear models) in STATISTICA®(12.0, Palo Alto, California, United States) was performed. Univariate one-way ANOVA was performed in order to compare the age, the IQ, and the number of words read in 1 min in the ELFE test and the visual attentional span test (the number of letters accurately reported across the trials) in two groups of children (G1 and G2). Repeated measurements of ANOVA were also run between the two children groups (G1 and G2) on the oculomotor parameters recorded at T1 and T2. An analysis of covariance (ANCOVA) on the duration of fixation with the total reading time as a covariable was also performed, in order to eliminate variance due to reading time differences. Post hoc comparisons were made with the Bonferroni test. The effect of a factor was considered significant when the p-value was below 0.05. 2.4. Data Analysis We used the software MeyeAnalysis (provided with the eye tracker, SuriCog, Paris, France) in order to calibrate and to extract saccadic eye movements from the data. The onset and the end of each saccade was automatically determined through a built-in saccade detection algorithm [37]. The number and the amplitude of saccades or prosaccades, the number of regressions, the duration of fixation, and the total duration of reading were calculated in a computerized manner for each reading task. Accuracy was not measured, given that the present study focuses on eye movement pattern changes before and after visual attentional training. 2 3 Procedure 2.3. Procedure 2.3. Procedure After the screening for dyslexia (done by the two coauthors, Dr. C.-L.G. and H.P.), the child was invited to participate in our experiment. Firstly, the examiners (two coauthors S.C. and M.P.B.) After the screening for dyslexia (done by the two coauthors, Dr. C.-L.G. and H.P.), the child was invited to participate in our experiment. Firstly, the examiners (two coauthors S.C. and M.P.B.) 6 of 13 Brain Sci. 2020, 10, 558 measured their reading age by the ELFE test; children were assigned randomly to each group (G1 or G2) in accordance to their performances in the VA and ELFE tests. Afterwards, the child underwent oculomotor recording (T1), and then only children of G1 (experimental group) underwent visual attentional training (i.e., both oculomotor types—without eye movements recording—and searching task by using the Metrisquare apparatus). In contrast, children of G2 (control group) did not perform the training, but they spoke for about 10 min with the two examiners. Then, T2 oculomotor recording was run for both groups of children (G1 and G2). The duration of all these tests was about 45 min because some breaks were done to avoid fatigue. 3. Results Table 1 shows clinical characteristics of the two groups of children with reading disorders (G1 and G2). The one-way ANOVA failed to report any statistical difference between G1 (experimental group) and G2 (control group) (F(1,48) = 0.15, p = 0.7; F(1,48) = 0.10, p = 0.8; F(1,48) = 0.02, p = 1.0; F(1,48) = 0.01, p = 0.9; F(1,48) = 0.03, p = 1.0; F(1,48) = 0.04, p = 0.8; and F(1,48) = 0.84, p = 0.4; respectively for the age, IQ, L2MA (oral and written languages and memory), ELFE test, and VA span test). 7 of 13 G2 E Brain Sci. 2020, 10, 558 Table 1. Clinica o t ol ou ) Table 1. Clinical characteristics of the two groups of dyslexic children (G1 = experimental group; G2 = control group) with mean and standard deviations of age (years), IQ, of words/min read in the ELFE test and visual attentional span test (the number of letters accurately reported across the trials). test and visual attentional span test (the number of letters accurately reported across the trials). G1 (n = 25) G2 (n = 25) G1 (n = 25) G2 (n = 25) Age (years) 9.56 ± 0.29 9.74 ± 0.38 IQ (WISC-IV) 100 ± 6 102 ± 5.1 ADHD-RS score 5.2 ± 1 4.9 ± 1.2 L2MA standard deviation from the mean Oral Language 2.8 2.9 Written Language 2.6 2.7 Memory 2.7 2.8 ELFE test 48 ± 5.3 50 ± 5.8 VA span 63 ± 3.0 60 ± 2.1 Note: For the L2MA test done in both group of children the standard deviation from normal mean is reported. Age (years) 9.56 ± 0.29 9.74 ± 0.38 IQ (WISC-IV) 100 ± 6 102 ± 5.1 ADHD-RS score 5.2 ± 1 4.9 ± 1.2 L2MA standard deviation from the mean Oral Language 2.8 2.9 Written Language 2.6 2.7 Memory 2.7 2.8 The ANOVA reported a significant training effect for the total reading time (F(1,48) = 4.78, β = 0.09 p < 0.03) and also a significant interaction T × G effect (F(1,48) = 39.56, β = 0.45 p < 0.0001). The Bonferroni post hoc test showed only that the time of reading for G1 (experimental group) at T2 decreased with respect to T1 (p < 0.0001) (see Figure 2). 3. Results ELFE test 48 ± 5.3 50 ± 5.8 VA span 63 ± 3.0 60 ± 2.1 Note: For the L2MA test done in both group of children the standard deviation from normal mean is reported. Figure 2. Means and standard deviations of the total time (s) of reading the text at T1 and T2 for both groups of children (G1 = experimental group; G2 = control group). Figure 2. Means and standard deviations of the total time (s) of reading the text at T1 and T2 for both groups of children (G1 = experimental group; G2 = control group). Figure 2. Means and standard deviations of the total time (s) of reading the text at T1 and T2 for both groups of children (G1 = experimental group; G2 = control group). Figure 2. Means and standard deviations of the total time (s) of reading the text at T1 and T2 for both groups of children (G1 = experimental group; G2 = control group). The ANOVA showed a significant training effect for the duration of fixation (F(1,48) = 6.43, β = 0.11 p < 0.01) and a significant interaction T × G effect (F(1,48) = 17.82, β = 0.27 p < 0.0001). The Bonferroni post hoc test showed that for G1 (experimental group) only, the duration of fixations at T2 was shorter in contrast to T1 (p < 0.0001). ANCOVA showed a significant group effect in T2 (F(1,48) = 10.70 p < 0.001), suggesting that all significant findings survived the removal of variance due to reading time differences (see Figure 3). The ANOVA showed a significant training effect for the duration of fixation (F(1,48) = 6.43, β = 0.11 p < 0.01) and a significant interaction T × G effect (F(1,48) = 17.82, β = 0.27 p < 0.0001). The Bonferroni post hoc test showed that for G1 (experimental group) only, the duration of fixations at T2 was shorter in contrast to T1 (p < 0.0001). ANCOVA showed a significant group effect in T2 (F(1,48) = 10.70 p < 0.001), suggesting that all significant findings survived the removal of variance due to reading time differences (see Figure 3). differences (see Figure 3). Table 2 shows the values of amplitude of prosaccades and regressions at T1 and T2 for both groups of children (G1 and G2). 3. Results ANOVA failed to show any significant group or time effect for either interaction g Table 2 shows the values of amplitude of prosaccades and regressions at T1 and T2 for both groups of children (G1 and G2). ANOVA failed to show any significant group or time effect for either interaction. interaction. Therefore, in order to explore the eventual effect of the text in Table 3, the total time of reading and the duration of fixation are reported for children of G1 (experimental group) who read Text 1 and Text 2 before and after training (at T1 and T2, respectively). ANOVA failed to show any significant text effect, suggesting no effect of the type of the text on reading performance. 8 of 13 Brain Sci. 2020, 10, 558 59 ± Figure 3. Means and standard deviations of the duration of fixations (ms) at T1 and T2 for both groups of children (G1 = experimental group; G2 = control group). Figure 3. Means and standard deviations of the duration of fixations (ms) at T1 and T2 for both groups of children (G1 = experimental group; G2 = control group). Figure 3. Means and standard deviations of the duration of fixations (ms) at T1 and T2 for both groups of children (G1 = experimental group; G2 = control group). Figure 3. Means and standard deviations of the duration of fixations (ms) at T1 and T2 for both groups of children (G1 = experimental group; G2 = control group). Finally, ANOVA reported only a significant interaction T × G effect for the number of regressions (F(1,48) = 6.02, β = 0.11 p < 0.02), as seen in Figure 4. The Bonferroni test failed to show any statistical difference between the groups and the time of testing (T1 and T2). Finally, ANOVA reported only a significant interaction T × G effect for the number of regressions (F(1,48) = 6.02, β = 0.11 p < 0.02), as seen in Figure 4. The Bonferroni test failed to show any statistical difference between the groups and the time of testing (T1 and T2). Brain Sci. 2020, 10, x FOR PEER REVIEW 9 of 1 Figure 4. Means and standard deviations of the number of prosaccades (A) and number of regressions Figure 4. 4. Discussion The aim of this study was to evaluate the effect of a short visual attentional training on the reading performance in French children with reading disabilities. Our results indicate that these children could benefit from a short visual attentional training for reading faster with a decrease in the duration of fixations. It should be noted, however, that such short visual attentional training did not lead to any change concerning the number and the amplitude of prosaccades and regressions. These findings are discussed below. In the literature, the beneficial effects of visual perceptual training on the reading comprehension and fluency in children with dyslexia were recently reviewed (see the review of Peters et al. [31] described in the Introduction). However, that in this review, only one study [33], recorded eye movements during reading of the text. In more details, Judica and collaborators evaluated reading skills after a reading training program (1 h, two times for week for 5 months) in a small group of nine children with dyslexia (age mean of 11 years old). Training consisted of both reading a word aloud or silently and writing it on the keyboard. Eye movements were recorded using an infrared pupil reflection system with recording frequency at 200 Hz, and the duration of fixation, the number, and the amplitude of pro saccades and regressions were measured. The authors reported after training a significant shortening of fixations, suggesting that training could facilitate the process of extracting visual information on the words. In other terms, dyslexic children became more efficient in extrapolating information from the unit of letters composing the word. Indeed, during the reading task the most important eye movement parameter is the duration of fixation, given that it is during this time that the reading process takes place. These findings suggested that visual attentional training could act on the neural network responsible of duration of fixations during reading task. In other words, the capability of orienting and focusing visuospatial attention could be improved by a visual attentional training type even if it is short in time. We recall that neuroimaging studies reported that a complex neural network is activated during reading, predominantly the left-hemisphere area of inferior frontal, temporoparietal, and occipitotemporal cortical regions [38]. Concerning attentional system, research found that it is associated to the cingulo-frontoparietal network, linked with frontostriatal and frontoparietal pathways [39]. 3. Results Mean and standard deviations of the total time of reading and of duration of fixation for children of G1 = experimental group, who read Texts 1 and 2 before and after training (in T1 and T2). Total Time of Reading (s) Duration of Fixation (ms) Before Training (T1) After Training (T2) Before Training (T1) After Training (T2) Text 1 Text 2 Text 1 Text 2 Text 1 Text 2 Text 1 Text 2 59 ± 5 57 ± 6 45 ± 6 47 ± 5 465 ± 25 475 ± 29 411 ± 21 415 ± 20 3. Results Means and standard deviations of the number of prosaccades (A) and number of regressions (B) at T1 and T2 for both groups of children (G1 = experimental group; G2 = control group). Figure 4. Means and standard deviations of the number of prosaccades (A) and number of regression Figure 4. Means and standard deviations of the number of prosaccades (A) and number of regressions (B) at T1 and T2 for both groups of children (G1 = experimental group; G2 = control group). 9 of 13 Brain Sci. 2020, 10, 558 Table 2. Means and standard deviations of the amplitude of prosaccades and regressions at T1 and T2 for both groups of children (G1 = experimental group; G2 = control group). Table 2. Means and standard deviations of the amplitude of prosaccades and regressions at T1 and T2 for both groups of children (G1 = experimental group; G2 = control group). Amplitude of Prosaccades (◦) Amplitude of Regressions (◦) T1 T2 T1 T2 G1 (experimental group) 2.7 ± 1.1 2.5 ± 0.1 2.6 ± 0.1 2.6 ± 0.1 G2 (control group) 2.5 ± 0.1 2.4 ± 0.1 2.7 ± 0.1 2.6 ± 0.1 Table 3. Mean and standard deviations of the total time of reading and of duration of fixation for children of G1 = experimental group, who read Texts 1 and 2 before and after training (in T1 and T2). Total Time of Reading (s) Duration of Fixation (ms) Before Training (T1) After Training (T2) Before Training (T1) After Training (T2) Text 1 Text 2 Text 1 Text 2 Text 1 Text 2 Text 1 Text 2 59 ± 5 57 ± 6 45 ± 6 47 ± 5 465 ± 25 475 ± 29 411 ± 21 415 ± 20 for both groups of children (G1 = experimental group; G2 = control group). Amplitude of Prosaccades (◦) Amplitude of Regressions (◦) T1 T2 T1 T2 G1 (experimental group) 2.7 ± 1.1 2.5 ± 0.1 2.6 ± 0.1 2.6 ± 0.1 G2 (control group) 2.5 ± 0.1 2.4 ± 0.1 2.7 ± 0.1 2.6 ± 0.1 Table 3. Mean and standard deviations of the total time of reading and of duration of fixation for children of G1 = experimental group, who read Texts 1 and 2 before and after training (in T1 and T2). Amplitude of Prosaccades (◦) Amplitude of Regressions (◦) Table 3. 4. Discussion In the literature, dyslexia has been associated to a dysfunctional connectivity of attentional networks as well as frontal and parietal regions [40]. These authors compared the resting state using fMRI in a group of 33 children with dyslexia (age range = 7.7–15.7 years) and in a group of control children (n = 11), and they found in children with dyslexia a reduced activity of left intraparietal Brain Sci. 2020, 10, 558 10 of 13 sulcus and left middle frontal gyrus; interestingly, they reported that the lower activity of these circuits was also associated with higher ratings of inattention. We could suggest that a visual attentional training could play an important role in the cerebral networks responsible of both eye movement control and attentional mechanisms, given that attention and eye movements are linked [41]. However, attentional tests could be introduced to further explore the role of attention abilities in dyslexic children to improve their reading capabilities. It should be noted, however, that such short visual attentional training did not lead to any change concerning the number and the amplitude of prosaccades and regressions. Judica et al. [33] reported similar findings, and they suggested that the lack of change in the number and the amplitude of saccades could be explained by the fact that the dyslexic child was not able to acquired information from the word as a single unit, and they still need to split the words. As discussed by Reichle and Sheridan [42], reading skills develop with age, and fixation duration is an important parameter for the reading capabilities. Interestingly, other studies in adult nondyslexic subjects showed improvement in reading capabilities by decreasing fixation durations and the number of saccades, in cases of a manipulation of text difficulty or text repetition [43] or shorter fixation durations when adult nondyslexic subjects had a text with larger spaces between the letters, but they failed to report any change in the number of fixations, in the total reading time, and in the comprehension scores [44]. Further studies on such issues will be necessary in order to better understand the relationship between the fixation and the saccade systems and their role in reading skills. We suggested that such an oculomotor pattern of children with dyslexia that consists of smaller and more frequent prosaccades and regressions could be explained by the children’s reduced visual attentional span. 4. Discussion The visual attentional span corresponded to the number of distinct visual elements that can be processed [35], and in the literature, it was reported that the orienting and focusing visuospatial attention is impaired in dyslexia [45]. More recently, Chen and colleagues [46], using a pathway analysis, studied the impact of visual attentional span in a group of 105 subjects with dyslexia (mean age 17 years old), and they observed that visual attentional span have an important impact on the reading comprehension, underlining the pivotal role of visuospatial pathways for reading processes. A reduced visual attentional span, in fact, did not permit the subjects to skip small words during reading as found in expert readers; after visual attentional training, dyslexic children are still reading as inexpert readers, and the pattern of the number and amplitude of saccades is not affected by our training type. Actually, in our coming studies we try to perform tests using visual exercises to increase the visual attention span in dyslexic children in order to explore possible improvement also in the number and amplitude of saccades during reading, as it has been recently showed by Zhao et al. [47]. 5. Limitations The present study has several limitations that are worth noting. First, we did not examine the psycholinguistic effect of the texts used, and the type of font is known to be quite complex for dyslexic children. Secondly, the paragraph that the child has to read was quite short given the technical set up of eye movement recordings, particularly due to the calibration of the eye tracker system. Indeed, to avoid head movements of the child during the reading task, a short paragraph was presented in the center of the screen, and reading accuracy was not recorded. Another important factor needing to be taken in account is the motivation of children; children of the control group may have been less motivated with respect to children of the experimental group. Further studies taking in account these arguments need to be done on a large group of dyslexic children by using a more ecological experimental setup. 11 of 13 ren up. Brain Sci. 2020, 10, 558 Another im of the control gr 11 of 13 ren up. 6. Conclusions children by Conflicts of Interest: The authors have no financial and personal relationships with other people or Conflicts of Interest: The authors have no financial and personal relationships with other people or organizat hat could inappropriately influence or bias their work in this study. for lending the Metrisquare© system, and Emilie Lacroix for leading the visual searching tests. Conflicts of Interest: The authors have no financial and personal relationships with other people or Availability of Supporting Data: The datasets analyzed during the current study are available from orresponding author on reasonable request. organizations that could inappropriately influence or bias their work in this study. Availability of Supporting Data: The datasets analyzed during the current study are available from the Availability of Supporting Data: The datasets analyzed during the current study are available from the corresponding author on reasonable request. organizations that could inappropriately influence or bias their work in this study. Availability of Supporting Data: The datasets analyzed during the current study are available from the Appendix A. Texts Used in T1 and T2 for Eye Movement Recording corresponding author on reasonable request. A di A Texts Used in T1 and T2 for Eye Mo ement Re ording Brain Sci. 2020, 10, x FOR PEER REVIEW 12 of 14 1. Peterson, R.L.; Pennington, B.F. Developmental dyslexia. Lancet 2012, 379, 1997–2007, doi:10.1016/s014 6736(12)60198-6 1. Peterson, R.L.; Pennington, B.F. Developmental dyslexia. Lancet 2012, 379, 1997–2007. [CrossRef] 6. Conclusions children by A short visual attentional training could improve the cortical mechanism responsible for focus attention and reading capabilities in children with dyslexia. Further studies will be necessary in order to test different training types for improving both visual attentional span and eye movements during reading in a dyslexic population. 6. Conclusions A short visual attentional training could improve the cortical mechanism responsible for focus attention and reading capabilities in children with dyslexia. Further studies will be necessary in order to test different training types for improving both visual attentional span and eye movements during Author Contributions: Conceptualization: M.P.B. and S.C.; selection of patients: C.-L.G. and H.P.; oculomotor measure and data analysis: S.C. and M.P.B.; writing original draft: S.C. and M.P.B.; review and editing: S.C., M.P.B., H.P., and C.-L.G. All authors have read and agreed to the published version of the manuscript. Author Contributions: Conceptualization: M.P.B. and S.C.; selection of patients: C.-L.G. and H.P.; oculomotor measure and data analysis: S.C. and M.P.B.; writing original draft: S.C. and M.P.B.; review and editing: S.C., M P B H P and C L G All authors have read and agreed to the published version of the manuscript Acknowledgments: The authors would like to thank the children who participated in the study, Ben Vaessen for lending the Metrisquare© system, and Emilie Lacroix for leading the visual searching tests. Funding: This research received no external funding. Acknowledgments: The authors would like to thank the children who participated in the study, Ben Vaessen f l di th M t i © t d E ili L i f l di th i l hi t t Acknowledgments: The authors would like to thank the children who participated in the study, Ben Vaessen ending the Metrisquare© system, and Emilie Lacroix for leading the visual searching tests. Funding: This research received no external funding. Acknowledgments: The authors would like to thank the children who participated in the study, Ben Vaessen f l di h M i © d E ili L i f l di h i l hi Conflicts of Interest: The authors have no financial and personal relationships with other people or organizat hat could inappropriately influence or bias their work in this study. for lending the Metrisquare© system, and Emilie Lacroix for leading the visual searching tests. 6736(12)60198-6. 2. Stein, J. What is Developmental Dyslexia? Brain Sci. 2018, 8, 26. 2. Stein, J. What is Developmental Dyslexia? Brain Sci. 2018, 8, 26. [CrossRef] [PubMed] Referenc References 1. Peterson, R.L.; Pennington, B.F. Developmental dyslexia. Lancet 2012, 379, 1997–2007, doi:10.1016/s0140- 6736(12)60198-6. 2. Stein, J. What is Developmental Dyslexia? Brain Sci. 2018, 8, 26. 3. Tallal, P. Auditory temporal perception, phonics, and reading disabilities in children. Brain Lang. 1980, 9, 182–198. 4. Stein, J.F.; Riddell, P.M.; Fowler, S. Disordered vergence control in dyslexic children. Br. J. Ophthalmol. 1988, 72, 162–166. 5. Eden, G.F.; Stein, J.F.; Wood, H.M.; Wood, F.B. Differences in eye movements and reading problems in dyslexic and normal children. Vis. Res. 1994, 34, 1345–1358. 6. Nicolson, R.I.; Fawcett, A.J. Automaticity: A new framework for dyslexia research? Cognition 1990, 35, 159– 182. 7. Facoetti, A.; Lorusso, M.L.; Paganoni, P.; Cattaneo, C.; Galli, R.; Mascetti, G.G. The time course of attentional focusing in dyslexic and normally reading children. Brain Cogn. 2003, 53, 181–184. 8. Bucci, M.P.; Nassibi, N.; Gerard, C.L.; Bui-Quoc, E.; Seassau, M. Immaturity of the oculomotor saccade and i i i d l i hild E id f di d i l h d PL S ONE 2012 1. Peterson, R.L.; Pennington, B.F. Developmental dyslexia. Lancet 2012, 379, 1997–2007. [CrossRef] 2. Stein, J. What is Developmental Dyslexia? Brain Sci. 2018, 8, 26. [CrossRef] [PubMed] 3. Tallal, P. Auditory temporal perception, phonics, and reading disabilities in children. Brain Lang. 1980, 9, 182–198. [CrossRef] 4. Stein, J.F.; Riddell, P.M.; Fowler, S. Disordered vergence control in dyslexic children. Br. J. Ophthalmol. 1988, 72, 162–166. [CrossRef] [PubMed] 5. Eden, G.F.; Stein, J.F.; Wood, H.M.; Wood, F.B. Differences in eye movements and reading problems in dyslexic and normal children. Vis. Res. 1994, 34, 1345–1358. [CrossRef] 6. Nicolson, R.I.; Fawcett, A.J. Automaticity: A new framework for dyslexia research? Cognition 1990, 35, 159–182. [CrossRef] 7. Facoetti, A.; Lorusso, M.L.; Paganoni, P.; Cattaneo, C.; Galli, R.; Mascetti, G.G. The time course of attentional focusing in dyslexic and normally reading children. Brain Cogn. 2003, 53, 181–184. [CrossRef] 1. Peterson, R.L.; Pennington, B.F. Developmental dyslexia. Lancet 2012, 379, 1997–2007, doi:10.1016/s0140 6736(12)60198-6 1. Peterson, R.L.; Pennington, B.F. Developmental dyslexia. Lancet 2012, 379, 1997–2007. [CrossRef] 2. Stein, J. What is Developmental Dyslexia? Brain Sci. 2018, 8, 26. 3. Tallal, P. Auditory temporal perception, phonics, and reading disabilities in children. Brain Lang. 1980, 9, 182–198. 3. Tallal, P. Auditory temporal perception, phonics, and reading disabilities in children. Brain Lang 1980, 9, 182–198. [CrossRef] 4. Stein, J.F.; Riddell, P.M.; Fowler, S. Disordered vergence control in dyslexic children. Br. J. Ophthalmol. Figure A1. Text 1. Figure A1. Text 1. Figure A2. Text 2. Figure A2. Text 2. Referenc References Binocular saccade coordination in reading and visual search: A developmental study in typical reader and dyslexic children. Front. Integr. Neurosci. 2014, 30, 85. [CrossRef] 10. Tiadi, A.; Seassau, M.; Gerard, C.L.; Bucci, M.P. Differences between Dyslexic and Non-Dyslexic Children in the Performance of Phonological Visual-Auditory Recognition Tasks: An Eye-Tracking Study. PLoS ONE 2016, 11, e0159190. [CrossRef] 11. Seassau, M.; Bucci, M.P. Reading and visual search: A developmental study in normal children. PLoS ONE 2013, 8, e70261. [CrossRef] [PubMed] 12. Rayner, K. Eye movements in reading and information processing: 20 years of research. Psychol. Bull. 1998, 124, 372–422. [CrossRef] [PubMed] 13. Loberg, O.; Hautala, J.; Hamalainen, J.A.; Leppanen, P.H.T. Influence of Reading Skill and Word Length on Fixation-Related Brain Activity in School-Aged Children During Natural Reading. Vis. Res. 2019, 165, 109–122. [CrossRef] [PubMed] 4. Olulade, O.A.; Flowers, D.L.; Napoliello, E.M.; Eden, G.F. Developmental differences for word processin the ventral stream. Brain Lang. 2013, 125, 134–145. [CrossRef] [PubMed] 15. Bucci, M.P. Visual training could be useful for improving reading capabilities in dyslexia. Appl. Neuropsychol. Child 2019, 13, 1–10. [CrossRef] 16. Palvidis, G.T. Do eye movements hold the key to dyslexia? Neuropsychologia 1981, 19, 57–64. 17. Rayner, K. Do faulty eye movements cause dyslexia? Dev. Neuropsychol. 1985, 1, 3–15. [CrossRef] 18. De Luca, M.; Di Pace, E.; Judica, A.; Spinelli, D.; Zoccoloti, P. Eye movement patterns in linguistic and non-linguistic tasks in developmental surface dyslexia. Neuropsychologia 1999, 37, 1407–1420. [CrossRef] 19. Trauzettel-Klosinski, S.; Koitzsch, A.M.; Dürrwächter, U.; Sokolov, A.N.; Reinhard, J.; Klosinski, G. Eye movements in German-speaking children with and without dyslexia when reading aloud. Acta Ophthalmol. 2010, 88, 681–691. [CrossRef] 0. Carroll, J.M.; Solity, J.; Shapiro, L.R. Predicting dyslexia using prereading skills: The role of sensorimotor cognitive abilities. J. Child Psychol. Psychiatry 2016, 57, 750–758. [CrossRef] 21. Blythe, H.I.; Kirkby, J.A.; Liversedge, S.P. Comments on: “What Is Developmental Dyslexia?” Brain Sci. 2018, 8, 26. The Relationship between Eye Movements and Reading Difficulties. Brain Sci. 2018, 8, 100. [CrossRef] [PubMed] 22. Bonacina, S.; Cancer, A.; Lanzi, P.L.; Lorusso, M.L.; Antonietti, A. Improving reading skills in students with dyslexia: The efficacy of a sublexical training with rhythmic background. Front. Psychol. 2015, 6, 1510. [CrossRef] [PubMed] 23. Solan, H.A.; Larson, S.; Shelley-Tremblay, J.; Ficarra, A.; Silverman, M. Role of visual attention in cognitive control of oculomotor readiness in students with reading disabilities. J. Learn. Disabil. 2001, 34, 107–118. [CrossRef] [PubMed] 24. Referenc References 1988, 72, 162–166. 4. Stein, J.F.; Riddell, P.M.; Fowler, S. Disordered vergence control in dyslexic children. Br. J. Ophthalmol. 1988, 72, 162–166. [CrossRef] [PubMed] 5. Eden, G.F.; Stein, J.F.; Wood, H.M.; Wood, F.B. Differences in eye movements and reading problems in dyslexic and normal children. Vis. Res. 1994, 34, 1345–1358. l I A A A f k f d l h? C i i 5. Eden, G.F.; Stein, J.F.; Wood, H.M.; Wood, F.B. Differences in eye movements and reading problems in dyslexic and normal children. Vis. Res. 1994, 34, 1345–1358. [CrossRef] 5. Eden, G.F.; Stein, J.F.; Wood, H.M.; Wood, F.B. Differences in eye movements and reading problems in dyslexic and normal children. Vis. Res. 1994, 34, 1345–1358. 5. Eden, G.F.; Stein, J.F.; Wood, H.M.; Wood, F.B. Differences in eye movements and reading problems in dyslexic and normal children. Vis. Res. 1994, 34, 1345–1358. [CrossRef] 6. Nicolson, R.I.; Fawcett, A.J. Automaticity: A new framework for dyslexia research? Cognition 1990, 35, 159– 182. 7 Facoetti A ; Lorusso M L ; Paganoni P ; Cattaneo C ; Galli R ; Mascetti G G The time course of 6. Nicolson, R.I.; Fawcett, A.J. Automaticity: A new framework for dyslexia research? Cognition 1990, 35, 159–182. [CrossRef] 6. Nicolson, R.I.; Fawcett, A.J. Automaticity: A new framework for dyslexia research? Cognition 1990, 35, 159– 182. 7 Facoetti A Lorusso M L Paganoni P Cattaneo C Galli R Mascetti G G The time course of 6. Nicolson, R.I.; Fawcett, A.J. Automaticity: A new framework for dyslexia research? Cognition 1990, 35, 159–182. [CrossRef] 7. Facoetti, A.; Lorusso, M.L.; Paganoni, P.; Cattaneo, C.; Galli, R.; Mascetti, G.G. The time course of attentional focusing in dyslexic and normally reading children. Brain Cogn. 2003, 53, 181–184. 8. Bucci, M.P.; Nassibi, N.; Gerard, C.L.; Bui-Quoc, E.; Seassau, M. Immaturity of the oculomotor saccade and 7. Facoetti, A.; Lorusso, M.L.; Paganoni, P.; Cattaneo, C.; Galli, R.; Mascetti, G.G. The time course of attentional focusing in dyslexic and normally reading children. Brain Cogn. 2003, 53, 181–184. [CrossRef] 12 of 13 Brain Sci. 2020, 10, 558 8. Bucci, M.P.; Nassibi, N.; Gerard, C.L.; Bui-Quoc, E.; Seassau, M. Immaturity of the oculomotor saccade and vergence interaction in dyslexic children: Evidence from a reading and visual search study. PLoS ONE 2012, 7, e33458. [CrossRef] 9. Seassau, M.; Gérard, C.L.; Bui-Quoc, E.; Bucci, M.P. Referenc References Meng, X.; Lin, O.; Wang, F.; Jiang, Y.; Song, Y. Reading performance is enhanced by visual texture discrimination training in Chinese-speaking children with developmental dyslexia. PLoS ONE 2014, 9, e108274. [CrossRef] 25. Bouma, H.; Legein, C.P. Foveal and parafoveal recognition of letters and words by dyslexics and by average readers. Neuropsychologia 1997, 15, 69–80. [CrossRef] 26. Perea, M.; Panadero, V.; Moret-Tatay, C.; Gómez, P. The effects of inter-letter spacing in visual-word recognition: Evidence with young normal readers and developmental dyslexics. Learn. Instruct. 2012, 22, 420–430. [CrossRef] 27. Zorzi, M.; Barbiero, C.; Facoetti, A.; Lonciari, I.; Carrozzi, M.; Montico, M.; Bravar, L.; George, F.; Pech-Georgel, C.; Ziegler, J.C. Extra-large letter spacing improves reading in dyslexia. Proc. Natl. Acad. Sci. USA 2012, 109, 11455–11459. [CrossRef] 28. Masulli, F.; Galluccio, M.; Gerard, C.L.; Peyre, H.; Rovetta, S.; Bucci, M.P. Effect of different font sizes and of spaces between words on eye movement performance: An eye tracker study in dyslexic and non-dyslexic children. Vis. Res. 2018, 153, 24–29. [CrossRef] 13 of 13 Brain Sci. 2020, 10, 558 29. Bucci, M.P.; Carzola, B.; Fiucci, G.; Potente, C.; Caruso, L. Computer Based Oculomotor Training Improves Reading Abilities in Dyslexic Children: Results from A Pilot Study. Sports Inj. Med. 2018, 2, 130. [CrossRef] 30. Cancer, A.; Bonacina, S.; Antonietti, A.; Salandi, A.; Molteni, M.; Lorusso, M.L. The Effectiveness of Interventions for Developmental Dyslexia: Rhythmic Reading Training Compared With Hemisphere-Specific Stimulation and Action Video Games. Front. Psychol. 2020, 11, 1158. [CrossRef] 31. Peters, J.L.; De Losa, L.; Bavin, E.L.; Crewther, S.G. Efficacy of dynamic visuo-attentional interventions for reading in dyslexic and neurotypical children: A systematic review. Neurosci. Biobehav. Rev. 2019, 100, 58–76. [CrossRef] [PubMed] 32. Łuniewska, M.; Chyl, K.; D˛ebska, A.; Kacprzak, A.; Plewko, J.; Szczerbi´nski, M.; Szewczyk, J.; Grabowska, A.; Jednoróg, K. Neither action nor phonological video games make dyslexic children read better. Sci. Rep. 2018, 8, 549. [CrossRef] [PubMed] 33. Judica, A.; De Luca, M.; Spinelli, D.; Zoccolotti, P. Training of developmental surface dyslexia improves reading performance and shortens eye fixation duration in reading. Neuropsychol. Rehabil. 2002, 12, 177–198. [CrossRef] 34. Chevrie-Muller, C.; Simon, A.M.; Fournier, S. Batterie Langage Oral Écrit. Mémoire. Attention (L2MA); Centre de Psychologie Appliquée: Paris, France, 1997. 35. Bosse, M.L.; Tainturier, M.J.; Valdois, S. Developmental dyslexia: The visual attention span deficit hyp Cognition 2007, 104, 198–230. [CrossRef] [PubMed] 36. Referenc References Chatard, H.; Tepenier, L.; Beydoun, T.; Offret, O.; Salah, S.; Sahel, J.A.; Mohand-Said, S.; Bucci, M.P. Effect of visual search training on saccades in age-related macular degeneration subjects. Curr. Aging Sci. 2019, 13. [CrossRef] 37. Lions, C.; Bui-Quoc, E.; Seassau, M.; Bucci, M.P. Binocular coordination of saccades during reading in strabismic children. Investig. Ophthalmol. Vis. Sci. 2013, 54, 620–628. [CrossRef] 38. Martin, A.; Schurz, M.; Kronbichler, M.; Richlan, F. Reading in the brain of children and adults: A meta-analysis of 40 functional magnetic resonance imaging studies. Hum. Brain Mapp. 2015, 36, 1963–1981. [CrossRef] 38. Martin, A.; Schurz, M.; Kronbichler, M.; Richlan, F. Reading in the brain of children and adults: A meta-analysis of 40 functional magnetic resonance imaging studies. Hum. Brain Mapp. 2015, 36, 1963–1981. [CrossRef] 39. Bush, G. Cingulate, frontal, and parietal cortical dysfunction in attention-deficit/hyperactivity disorder. Bi l P hi t 2011 69 1160 1167 [C R f] 39. Bush, G. Cingulate, frontal, and parietal cortical dysfunction in attention-deficit/hyperactivity disorder. Biol. Psychiatry 2011, 69, 1160–1167. [CrossRef] 40. Koyama, M.S.; Di Martino, A.; Kelly, C.; Jutagir, D.R.; Sunshine, J.; Schwartz, S.J.; Castellanos, F.X.; Milham, M.P. Cortical signatures of dyslexia and remediation: An intrinsic functional connectivity approach. PLoS ONE 2013, 8, e55454. [CrossRef] , , [ ] 41. Rizzolati, G.; Riggio, L.; Dascola, I.; Umiltà, C. Reorienting attention across the horizontal and vertical meridians: Evidence in favour of a premotor theory of attention. Neuropsychologia 1987, 125, 31–40. [CrossRef] 42. Reichle, E.D.; Sheridan, H. E-Z Reader: An Overview of the Model and Two Recent Applications. In The Oxford Handbook of Reading; Pollatsek, A., Treiman, R., Eds.; Oxford University Press: Oxford, UK, 2015. [CrossRef] 43. Raney, G.E.; Rayner, K. Word frequency effects and eye movements during two readings of a text. Can. J. 41. Rizzolati, G.; Riggio, L.; Dascola, I.; Umiltà, C. Reorienting attention across the horizontal and vertical meridians: Evidence in favour of a premotor theory of attention. Neuropsychologia 1987, 125, 31–40. [CrossRef] meridians: Evidence in favour of a premotor theory of attention. Neuropsychologia 1987, 125, 31–40. [CrossRef] 42. Reichle, E.D.; Sheridan, H. E-Z Reader: An Overview of the Model and Two Recent Applications. In The Oxford Handbook of Reading; Pollatsek, A., Treiman, R., Eds.; Oxford University Press: Oxford, UK, 2015. [CrossRef] 43. Raney, G.E.; Rayner, K. Word frequency effects and eye movements during two readings of a text. Can. J. Exp Psychol 1995 151–172 [CrossRef] [PubMed] 42. © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). Referenc References Reichle, E.D.; Sheridan, H. E-Z Reader: An Overview of the Model and Two Recent Applications. In The Oxford Handbook of Reading; Pollatsek, A., Treiman, R., Eds.; Oxford University Press: Oxford, UK, 2015. [CrossRef] 43. Raney, G.E.; Rayner, K. Word frequency effects and eye movements during two readings of a text. Can. J. Exp. Psychol. 1995, 151–172. [CrossRef] [PubMed] 44. Perea, M.; Giner, L.; Marcet, A.; Gomez, P. Does extra interletter spacing help text reading in skilled adult readers? Span. J. Psychol. 2016, 19, E26. [CrossRef] [PubMed] 45. Facoetti, A.; Paganoni, P.; Turatto, M.; Marzola, V.; Mascetti, G.G. Visual-spatial attention in developmental dyslexia. Cortex 2000, 36, 109–123. [CrossRef] 6. Chen, C.; Schneps, M.H.; Masyn, K.E.; Thomson, J.M. The Effects of Visual Attention Span and Phonolog Decoding in Reading Comprehension in Dyslexia: A Path Analysis. Dyslexia 2016, 22, 322–344. [CrossR 47. Zhao, J.; Liu, H.; Li, J.; Sun, H.; Liu, Z.; Gao, J.; Liu, Y.; Huang, C. Improving sentence reading performance in Chinese children with developmental dyslexia by training based on visual attention span. Sci. Rep. 2019, 9, 18964. [CrossRef] © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
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Leaching and uptake of nitrogen and phosphorus from cow slurry and fox manure in a lysimeter trial
Agricultural and food science
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© Agricultural Science in Finland Manuscript received January 1995 Leaching and uptake of nitrogen and phosphorus from cow slurry and fox manure in a lysimeter trial Erkki Kemppainen Agricultural Research Centre ofFinland, FIN-31600 Jokioinen, Finland The effects of soil type, spreading time and use of a nitrification inhibitor (Didin) on the leaching and uptake of nitrogen and phosphorus from cow slurry and fox manure were studied in a lysimeter trial during 1989-1992. The runoff volume and leaching of total nitrogen in peat soil were double those in fine sand soil. There was no essential difference in the leaching of nitrate nitrogen, but the amount of ammonium nitrogen leached from peat soil was 50-fold and that of organic nitrogen about 3-fold the amounts leached from fine sand soil. The amount of total phosphorus leached from peat soil was 23-fold and that of soluble phosphorus 39-fold the amounts leached from fine sand soil. There were only minor differences between cow slurry and fox manure in the leaching of nitrogen. The least nitrogen was leached after manure application in May. Didin did not have any significant effect. In peat soil, significantly more phosphorus leached from fox manure than from cow slurry. Spreading time had no effect on phosphorus leaching. Considerably higher barley grain yields were harvested from peat soil than from fine sand soil. Fox manure proved to be a much more effective fertilizer than cow slurry. In the first experimental year, December spreading resulted in a lower yield than other spreading times. Of the total nitrogen ap- plied in manure, 24-41% was recovered in barley yield (grain+straw) and 4-21% in runoff; the fig- ures for phosphorus were 6-51% and 0-2,6%, respectively. Key words: peat soil, fine sand soil, spreading time, nitrification, nitrification inhibitor, nitrate, am- monium, organic nitrogen, soluble phosphorus, runoff Material and methods Not only manure nitrogen but also manure phosphorus poses a threat to the environment when leached from fields. The phosphorus con- tent of even a moderate dose of manure may of- ten be too high for a crop. Moreover, manure phosphorus is more mobile in soil and thus more susceptible to leaching than the phosphorus in mineral fertilizer (Vetter and Steffens 1981). A lysimeter field with 66 small lysimeters (il- lustrated in Fig. 1)was set up at the Agricultural Research Centre of Finland, Kainuu Research Station, Sotkamo (64° 06’N, 28° 20’E) in sum- mer 1989.All the lysimeters are monoliths. Half of them were filled with cultivatedfine sand soil and half with Carex peat soil (Table 1).The treat- ments used in the experiment are given in Table 2. There were three replicates. German studies show that acid peat soils are susceptible to phosphorus leaching (Scheffer et al. 1981, Vetter and Steffens 1981). Very high amounts of phosphorus can leach through a peat soil when manure is applied in large quantities (Scheffer etal. 1981. Bartels and Scheffer 1987). The risk of phosphorus leaching from acid peat soils appears to have been overlooked in Fin- land even though peat fields account for over 20% of the arable area. Before the experiment was set up, the lysim- eter soils were all turned (ploughed) to a depth of 10 cm. Manures applied to lysimeter soils in September were harrowed into the soil about three hours after spreading. In December, the manures were spread on a 3-4-cm-thick snow cover. In May, they were first spread on lysime- ter soils which had been harrowed to a depth of 10cm and were then harrowed into the soil three days after application. The nutrient content of manures and the amounts of nutrients applied to the lysimeter soils are presented in Table 3. Ma- nure samples were analysed according to Kemp- painen (1989b). Fur animal manure is particularly problem- atic for environmental protection, as manures of mink and fox contain about 10 times more ni- trogen and 30 times more phosphorus than cow slurry (Kemppainen 1984). Thus fur animal ma- nures often cause considerable environmental problems on farms (Pedersen 1991). Owing to the high nutrient content ofthe manures it is very difficult to spread them at rates low enough to avoid overfertilization. Moreover, many fur an- imal farms have too small an arable area for manure spreading. Kemppainen, E.: Leaching and uptake ofnitrogen and phosphorus... manures: cow slurry and fox manure. Cow slur- ry was chosen because it is an important type of manure on Finnish farms, and fox manure be- cause of its widespread use in eastern Finland and Ostrobothnia. Only a few studies on the fer- tilizer value and environmental impacts of fox manure, a very concentrated type of manure, have been published. Two soil types typical of northernFinland were chosen for the experiment: Carex peat and fine sand. The effects of spread- ing timeand use of a nitrification inhibitorwere also studied. manure. Owing to insufficient storage capacity, about one-third of the manure produced in Fin- land has to be spread in autumn and some in winter. One way in which the hazards of nitrogen leaching have been overcome is by preventing the oxidation of manure ammonia with nitrifi- cation inhibitors. The use of inhibitors in com- bination with manure application in autumn has given rather good results. However, the profita- bility of inhibitor use is still unclear (Amberger 1981, Kjellerup 1986, Pain et al. 1987, Görlitz et al. 1988, Kemppainen 1989a, Tveitnes and Håland 1989,Görlitz 1990, Meissner et al. 1991, Nilsson 1991). Introduction ing. The same has been suggested in many re- ports published elsewhere (e.g. Brink et al, 1979, Vetter and Steffens 1981,Brink and Jernlås 1982, Herrmann et al. 1983). The leaching ofnutrients from livestock manures has been studied rather little in Finland. Yet re- sults published by Melanen et al. (1985) and Niinioja (1993) indicate that the use oflivestock manure can result in considerable nutrient leach- Many farms produce excessive amounts of livestock manure in relation to their field area. Another reason for excessive manuring may be that farmers do not know the fertilizer value of 363 AGRICULTURAL SCIENCE IN FINLAND Kemppainen, E.: Leaching and uptake ofnitrogen and phosphorus... AGRICULTURAL SCIENCE IN FINLAND Kemppainen, E.: Leaching and uptake ofnitrogen and phosphorus... Table 2. Treatments of various lysimeters. Soil Manure Manure Spreading/ Spreading date type type rate treatment Carex Cow 48 t/ha September 26,09.1989 peat slurry " " + Didin (15 kg/ha) 26.09.1989 ” " " December 19,12.1989 " " " May 11.05.1990 " Fox 23 t/ha September 26.09,1989 " manure " " +Didin (15 kg/ha) 26.09.1989 " " " December 19.12.1989 " " ” May 11.05.1990 Fine Cow 48 t/ha September 26.09.1989 sand slurry " " +Didin (15 kg/ha) 26.09.1989 " " " December 19.12.1989 " " ” May 11.05.1990 " Fox 23 t/ha September 26.09.1989 manure " " +Didin (15 kg/ha) 26.09.1989 " ” " December 19.12.1989 " " " May 11.05.1990 Carex Unfert. - - - peat NPK 500 kg/ha May 14.05.1990 Fine Unfert. - - sand NPK 500 kg/ha May 14.05.1990 Kemppainen, E.: Leaching and uptake ofnitrogen and phosphorus... Table 2. Treatments of various lysimeters. pies conserved withsulphuric acid. The amount of organic nitrogen was calculated by subtract- ing nitrate and ammonium nitrogen from the amount of total nitrogen. Combined results for the whole experimental period are mostly pre- sented. In some cases, however, results for short- er leaching periods are given as follows: The majority of the lysimeters functioned well; a few had to be discarded owing to excep- tionally small runoff. The results for unfertilized peat are based on only two replicates and those for unfertilized fine sand on one lysimeter. pies conserved withsulphuric acid. The amount of organic nitrogen was calculated by subtract- ing nitrate and ammonium nitrogen from the amount of total nitrogen. Combined results for the whole experimental period are mostly pre- sented. In some cases, however, results for short- er leaching periods are given as follows: In addition to nutrient leaching, grain and straw yields were measured and their nitrogen and phosphorus contents analysed according to Kähäri and Nissinen (1978). Nitrogen and phos- phorus uptake was calculated. The proportion of manure nitrogen and phosphorus in the yield and runoff was calculated by first subtracting the periodi 26.09.1989-09.05.1990 period II 10.05.1990-28.05.1991 period 111 29.05.1991 - 15.05.1992 period IV 16.05.1992-05.11.1992 Table 3. Nutrient content of different manure types (g/kg, on fresh weight basis) and amounts of nutrients applied to lysimeter soils (kg/ha). Material and methods Spring barley (Hordeutn vulgare var. Arra, 500 germinating seeds/m 2 ) was grown in lysim- eters during 1990-1992. During 1991 and 1992, the residual effects of different treatments were studied and the lysimeters were fertilized equal- ly with mineral fertilizer (N-P-K = 85-30- 60 kg/ha). This study compares the leaching and uptake of nitrogen and phosphorus from two different 364 AGRICULTURAL SCIENCE IN FINLAND Vol. 4: 363-375. Fig. 1.Diagram of a lysimeter. Vol. 4: 363-375. Fig. 1.Diagram of a lysimeter. Water tanks were emptied and water samples taken from the lysimeters 13 times. The amount of water was measured by weighing. Total ni- trogen, nitrate nitrogen, ammonium nitrogen, total phosphorus and soluble phosphorus contents were analysed as required by Finnish standards (SFS 3031, SFS 3030, SFS 3032 and SFS 3026). Phosphorus was analysed on sam- Table 1. Chemical properties of experimental soils. Nutrients were determined according to Vuorinen and Mäkitie (1955), and pH from a mixture of soil/deionized water = 1/2.5. Soil type pH mg/1 Ca K Mg P Fine sand soil 6.3 1170 110 79 10,4 Carex peal soil 5.0 800 43 239 3.0 ble 1. Chemical properties of experimental soils. Nutrients were determined according to Vuorinen and äkitie (1955), and pH from a mixture of soil/deionized water = 1/2.5. 365 AGRICULTURAL SCIENCE IN FINLAND Runoff 11.5kg/ha). The most striking difference was in the leaching of ammonium N: about 50 times more ammonium N leached from peat soil than from fine sand soil. However, there was no sig- Throughout the experimental period significantly more water percolated through manure-treated peat soil than through fine sand soil (Table 4), the percolation level corresponding to 49% and 24% of precipitation, respectively. Runoff was exceptionally high during the third leaching pe- riod (Fig. 2). The figure also shows that the dif- ference between soil types increased steadily as the experiment proceeded. Table 4. Runoff from lysimeters. Averages for soil types, manure types and spreading times, and figures for control treatments. Table 4. Runoff from lysimeters. Averages for soil types, manure types and spreading times, and figures for control treatments. Table 4. Runoff from lysimeters. Averages for soil types, manure types and spreading times, and figures for control treatments. Treatment Number of lysimeters Runoff, mm Peat soil 24 820 Fine sand soil HSD (P = 0.05) 24 406 322 Cow slurry Fox manure 24 671 24 555 HSD (P = 0.05) 97 September September+Didin December May HSD (P = 0,05) 12 678 12 667 12 618 12 490 160 No significant interactions Peat Unfert. 2 3 294 NPK 784 Fine Unfert. sand NPK 1 528 3 370 Less water percolated through lysimeter soils fertilized with fox manure than through those fertilized with cow slurry. There always seemed to be less runoff water from lysimeters manured in May than from other spreading treatments. Runoff from control treatments was of the same order as from lysimeters fertilized withlivestock manure. However, there was substantially less runoff from unfertilized peat thanfrom otherpeat soils. AGRICULTURAL SCIENCE IN FINLAND Nutrient g/kg kg/ha Cow Fox Cow Fox NPK Total N 3.47 24.55 167 565 85 Soluble N 2.15 14.32 103 329 85 Total P 0.72 29.50 35 679 30 Total K 3.63 9.27 174 213 60 366 Vol. 4: 363-375. Vol. 4: 363-375. Fig. 2. Cumulative runoff from manure-treated peat and fine sand soil lysimeters. amounts of N and P in the corresponding unfer- tilized treatments. The experiment was set up and the results were calculated according to the split-split-plot design. The main plots consisted of two soil types, subplots of two manure types, and sub- subplots of four spreading treatments. In some cases, one-way variance analyses were also ap- plied. AVAX 11/780computer and SAS program were used for the calculations (SAS Institute 1985). Results Fig. 2. Cumulative runoff from manure-treated peat and fine sand soil lysimeters. Leaching of nitrogen More ammonium N, organic N and total N leached from manure-treatedpeat soil thanfrom fine sand soil (Table 5). One-way variance anal- ysis showed that the difference in the leaching of total N was statistically significant (HSD = 367 AGRICULTURAL SCIENCE IN FINLAND Vol. 4: 363-375. phorus way variance analysis demon ferences were statistically s (HSD = 660kg/ha) and in 19 ha). Fox manure invariably grain yields than cow slurry. mental year, the advantage rus leached from 23 times that from difference in the us was 39-fold. iance analysis, the ignificant (HSD for P = 899 g/ha). The total P/ha, was for l in December. Table 6. Leaching of total and Averages for soil types, manure type and figures for control treatments. Treatment Tota g/h rom peat soil was e latter two leach- rmer two (Fig. 5). he differences be- increased towards More phosphorus n from cow slurry rus, however, this e sand soil, leach- bout 100 g/ha) and pe. No differences g times. Peat soil 22 Fine sand soil HSD (P = 0.05) Cow slurry 227 6 Fox manure 17 HSD (P = 0.05) September 10 11 September+Didin December May 7 15 12 HSD (P = 0.05) 18 Significant interactions: - soil x manure ields Peat Unfert. 2 NPK 7 ys harvested from oil (Table 7). One- Fine Unfert. sand NPK 1 nitrogen from unferti- red in September and Fig. 5. Cumulative leaching of tota manure in peat soil, cow slurry in p fine sand soil. LTURAL SCIENCE IN FINLAND 3-375. Fig. 5. Cumulative leaching of total phosphorus from fox manure in peat soil, cow slurry in peat soil and manures in fine sand soil. Vol. 4: 363-375. Vol. 4: Fig. 4. Cumulative leaching of total nitrogen from unferti- lized lysimeters and from those manured in September and in May. 3-375. Fig. 5. Cumulative leaching of total phosphorus from fox manure in peat soil, cow slurry in peat soil and manures in fine sand soil. Fig. 4. Cumulative leaching of total nitrogen from unferti- lized lysimeters and from those manured in September and in May. Leaching of phosphorus way variance analysis demonstratedthat the dif- ferences were statistically significant in 1991 (HSD = 660kg/ha) and in 1992 (HSD = 410 kg/ ha). Fox manure invariably produced higher grain yields than cow slurry. In the last experi- mental year, the advantage gained by fox ma- The amount of total phosphorus leached from manure-treated peat soil was 23 times that from fine sand soil (Table 6). The difference in the leaching of soluble phosphorus was 39-fold. According to one-way variance analysis, the differences were statistically significant (HSD for total P = 979 g/ha, for soluble P = 899 g/ha). The highest single figure, 4609 g total P/ha, was for fox manure applied to peat soil in December. Treatment Total P Soluble P g/ha g/ha Peat soil 2264 1848 Fine sand soil HSD (P = 0.05) Cow slurry 99 47 2271 2102 611 437 Fox manure 1752 1457 HSD (P = 0.05) September 1098 1042 1142 897 September+Didin December May 779 570 1567 1275 1238 1048 HSD (P = 0.05) 1818 1682 Significant interactions: - soil x manure * Peat Unfert. 239 106 NPK 709 520 Fine Unfert. sand NPK 62 19 124 33 Leaching of phosphorus from peat soil was considerably higher during the latter two leach- ing periods than during the former two (Fig. 5). The figure also shows that the differences be- tween soil and manure types increased towards the end of the experiment. More phosphorus leached from fox manure than from cow slurry (Table 6). For total phosphorus, however, this was true only in peat soil. In fine sand soil, leach- ing of total P was very low (about 100 g/ha) and not connected with manure type. No differences were found between spreading times. Kemppainen , E.: Leaching and uptake ofnitrogen andphosphorus nificant difference in the leaching of nitrate N. The proportion of total nitrogen that was nitrate nitrogen in percolated water increased in the course of the experiment in both soil types (Fig. 3). In peat soil, the proportion of ammoni- um nitrogen remained significant towards the end of the experiment whereas in fine sand soil it was low throughout. nificant difference in the leaching of nitrate N. The proportion of total nitrogen that was nitrate nitrogen in percolated water increased in the course of the experiment in both soil types (Fig. 3). In peat soil, the proportion of ammoni- um nitrogen remained significant towards the end of the experiment whereas in fine sand soil it was low throughout. As a whole, manure type had no effect on the leaching of the various nitrogen fractions. However, in peat soil slightly more total N, ni- trate N and ammonium N seemed to leach from fox manure than from cow slurry but in fine sand soil the situation was reversed. Leaching of all nitrogen fractions was lowest in spring-applied manure. For ammonium nitrogen, however, this was true only in peat soil. In fine sand soil, leach- ing of ammonium nitrogen was negligible (0.3- 0.4 kg/ha) at all spreading times. Didin did not decrease nitrogen leaching. Manure spreading time exerted an influence throughout the ex- perimental period (Fig. 4). Fig. 3. Proportion of organic, ammonium and nitrate nitro- gen relative to total nitrogen in runoff from manure-treated lysimeters during various leaching periods. Table 5. Leaching of nitrate, ammonium, organic and total nitrogen. Averages forsoil types, manure types and spreading times, and figures for control treatments. Treatment NOj-N nh4-n Org.N kg/ha Tot.N kg/ha kg/ha kg/ha Peat soil 33.8 15.2 19.9 68.8 Fine sand soil HSD (P = 0,05) Cow slurry 27.9 0.3 6.9 35.2 50.1 3.8 5.6 47.9 32.5 7.1 14.2 53.9 Fox manure 29.2 8.4 12.5 50.1 HSD (P = 0.05) September 6.7 1.4 2.9 7.0 35.4 9.1 15.0 59.6 September+Didin December May 33.3 9.1 15.5 57.9 33.0 8.3 13.5 54.8 21.6 4.5 9.5 35.6 HSD (P = 0.05) 14.8 3.9 4.9 18.6 Significant interactions: - soil x manure * * - soil x spreading Peat L ** Unfert. NPK 10.0 3.4 6.5 19.9 28.5 12.9 13.3 54.6 Fine sand Unfert. NPK 15.1 0.2 3.6 18.8 14.9 0.3 3.8 19.0 368 GRICULTURAL SCIENCE IN FINLAND Kemppainen, E.: Leaching and uptake ofnitrogen and phosphorus. Fig. 6. Manure nitrogen in barley yield (grain+straw) and in runoff during the whole experimental period. Compari- son of soil and manure types. nure was rather small in peat soil but substan- tially higher in fine sand soil. In the first experimental year, spreading in December resulted in a lower yield than other treatments. Cow slurry produced the highest yield when spread in May and fox manure when spread in September with Didin. In the second year, there were no significant differences be- tween the spreading treatments but, in the third year, spring application proved to be better than spreading in September with Didin. However, whilst differences between the various treatments with cow slurry were rather small, fox manure clearly produced the best yield when spread in spring. Comparison with unfertilized lysimeters in- dicated that very high yield increases were achieved with various fertilization treatments in thefirst year. In the second and third experimen- tal years, there were substantial residual effects, especially with fox manure. Fig. 6. Manure nitrogen in barley yield (grain+straw) and in runoff during the whole experimental period. Compari- son of soil and manure types. Barley grain yields Higher grain yields were always harvested from peat soil than from fine sand soil (Table 7). One- 369 AGRICULTURAL SCIENCE IN FINLAND Vol. 4: 363-375. Fig, 7. Manure nitrogen in barley yield (grain+straw) and in runoff during the whole experimental period. Compari- son of various spreading treatments. Fig. 8. Manure phosphorus in barley yield (grain+straw) and in runoff during the whole experimental period. Com- parison of soil and manure types. Vol. 4: 363-375. 3-375. Fig. 8. Manure phosphorus in barley yield (grain+straw) and in runoff during the whole experimental period. Com- parison of soil and manure types. Fig, 7. Manure nitrogen in barley yield (grain+straw) and in runoff during the whole experimental period. Compari- son of various spreading treatments. Fig, 7. Manure nitrogen in barley yield (grain+straw) and in runoff during the whole experimental period. Compari- son of various spreading treatments. Fig. 8. Manure phosphorus in barley yield (grain+straw) and in runoff during the whole experimental period. Com- parison of soil and manure types. soil. Of applied total phosphorus, 11.1% was found in barley and 0.6% in runoff from peat soil; the figures for fine sand soil were 6.2% and 0%, respectively. were of the same order for applications in Sep- tember, September+Didin and December, but substantially lower after application in May. Of applied total nitrogen, 33%, 40%, 24% and 34% were found in barley after manure application in September,September+Didin, December and May, respectively; thefigures for nitrogen found in runoff were 11%, 11%, 10% and 4%, respec- tively. Barley fertilized with fox manure contained much higheramounts of manure phosphorus than that fertilized with cow slurry. In peat soil, a corresponding difference was evident in the leaching of manure phosphorus. Of applied to- tal phosphorus, 50.6% was found in barley and 2.6% in runoff from cow slurry in peat soil, and 9.1% in barley and 0.5% in runoff from fox ma- nure. In fine sand soil, recovery of manure phos- phorus in barley was 19.1% for cow slurry and 5.5% for fox manure. In peat soil, recovery of fertilizer nitrogen (NPK plots, 85 kg N/ha) in barley was about 150% and in runoff 41%. In fine sand soil, 46% of nitrogen applied in mineral fertilizer was re- covered in barley but none in runoff. Recovery of manure phosphorus in barley was highest after application in May and lowest after application in December (Fig. 9). The amount ofmanure phosphorus leached was high- est after application in December but the differ- ences between treatments were rather small. AGRICULTURAL SCIENCE IN FINLAND Of applied total phosphorus, 8.4%, 9.4%, 7.3% and 9.6% were found in barley after manure appli- cation in September, September+Didin, Decem- ber and May, respectively; the figures for phos- Calculated proportion of manure nitrogen in yield and runoff Table 7. Barley grain yields. Averages for soil types, ma- nure types and spreading times,and figures for control treat- ments. Table 7. Barley grain yields. Averages for soil types, ma- nure types and spreading times,and figures for control treat- ments. Substantially higher amounts of manure nitro- gen were found in barley (grain+straw) from peat soil than from fine sand soil (Fig. 6). The amounts of manure nitrogen leached from peat soil were higher, too. Of applied total nitrogen, 41% was found in the yield and 13% in runoff from peat soil, and 25% in the yield and 5% in runoff from fine sand soil. Barley grain yield, kg/ha Treatment 1990 1991 1992 Peat soil 8000 6460 4950 Fine sand soil 5750 5020 4130 HSD (P =0.05) 1800 2350 1190 Cow slurry 4720 5230 4290 Fox manure 9030 6250 4800 HSD (P =0.05) 980 1040 90 September 6990 5740 4430 September+Didin 7770 5740 4180 December 5310 5830 4630 May 7440 5660 4930 HSD (P = 0.05) 1130 1060 600 Significant interactions - soil x manure *** manure x spreading ** * Peat Unfert. 1830 5230 4090 NPK 6970 6010 6000 Fine Unfert. 1280 4390 3930 sand NPK 4680 4220 3800 Barley treated with fox manure contained much higher amounts of manure nitrogen than that fertilized with cow slurry. However, the amounts of nitrogen leached from fox manure were only similar to or lower than those leached from cow slurry. Of applied total nitrogen, 33% was found in barley and 5% in runoff from fox manure, and 34% in barley and 21% in runoff from cow slurry. Recovery of manure nitrogen in barley was highest after application in September with Di- din, and lowest after application in December (Fig. 7). Amounts of manure nitrogen leached 370 GRICULTURAL SCIENCE IN FINLAND Calculated proportion of manure phosphorus in yield and runoff Substantially higher amounts of manure phos- phorus were found in barley (grain+straw) from peat soil than from fine sand soil (Fig. 8). Sig- nificant amounts of manure phosphorus leached from peat soil but practically none from fine sand 371 Kemppainen, E.; Leaching and uptake ofnitrogen andphosphorus... Fig. 9. Manure phosphorus in barley yield (grain+straw) and in runoff during the whole experimental period. Com- parison of various spreading treatments. Considerable leaching of ammonium nitrogen from peat soil was found by Jaakkola and Yläran- ta (1985). Considerable leaching of ammonium nitrogen from peat soil was found by Jaakkola and Yläran- ta (1985). Substantially more phosphorus leached from peat soil than from fine sand soil, indicating the low capacity of peat soil to bind phosphorus. Marked differences in the phosphorus binding capacity of mineral soils and organogenic soils were noted by Steenvoorden and Oosterom (1981) and Uhlen and Österud (1992). Very high phosphorus losses from manure-treatedpeat soils were demonstrated by Scheffer et al. (1981) and Bartels and Scheffer (1987). A conspicuous feature of this study was the high P loss during the two latter leaching periods, especially from fox manure in peat soil. It seems that the leaching of phosphorus began about two years after manure application. It is probable that significant P losses will occur af- ter the end of the experiment and the differences between various treatments will still increase. Fig. 9. Manure phosphorus in barley yield (grain+straw) and in runoff during the whole experimental period. Com- parison of various spreading treatments. Fig. 9. Manure phosphorus in barley yield (grain+straw) and in runoff during the whole experimental period. Com- parison of various spreading treatments. Fox manure was superior to cow slurry with respect to barley yields and nutrient uptake. However, the leaching of total nitrogen from fox manure was more or less the same as that from cow slurry even though the amount of total ni- trogen supplied in fox manure was 3.4-fold that in cow slurry. The luxuriantvegetation produced by fox manure used much waterand thus reduced runoff more effectively than cow slurry. Ample fertilization and subsequent luxuriant growth have been shown to reduce runoff in other studies, too (Eder 1985, Jaakkola and Yläranta 1985, Stauffer and Enggist 1990). phorus found in runoff were 0.3%, 0.2%, 0.4% and 0.3%, respectively. Of applied fertilizer phosphorus (30 kg P/ha) in NPK plots, 78.8% was found in barley and 1.6% in runoff from peat soil; thefigures for fine sand soil were 26.1% and 0.2%, respectively. Discussion The phenomenon described above, that is, a higher nutrient amount increasing yield and nu- trient uptake but not nutrient leaching, is possi- ble only when other growth factors do not limit plant growth. Growing conditions seem to have been surprisingly good in the lysimeters because barley was able to utilize the high level of nitro- gen supplied by fox manure. However, these re- sults are not comparable to those at field scale, where leaching becomes important at substan- tially lower nitrogen levels. Peat soil was superior to fine sand soil with re- spect to barley yields and nutrient uptake. How- ever, nutrient leaching from peat soil was also usually higher. As to leaching of total N and or- ganic N, the difference is explained partly by higher natural leaching and partly by high run- off from peat soil. High leaching of ammonium nitrogen from peat soil is partly due to significant mineraliza- tion of its organic nitrogen and partly to manure ammonia. Owing to the low pH, ammonia oxi- dizes slowly in peat (Alexander 1991, p. 252). Nitrogen uptake by barley was highest after treatment with manure with Didin in September, 372 Vol. 4: 363-375. Vol. 4: 363-375. effective at saving nitrogen (Amberger 1989, Asmus 1989, Görlitz 1989). According to Am- berger (1991) Didin may have a poor effect if manure is spread too early. Didin then decom- poses and loses its effect before winter. In this study, slurry treated with Didin was spread in late September, which, according to Kemppai- nen (1989a), is usually a favourable time for Di- din in Finland. However, after application, the soil temperature fell from about 11°C to 3-4°C in a few days and remained very low until the soil froze at the end ofNovember. It is thus very unlikely thatDidin lost its effect through decom- position during the autumn. It is more likely that the soil temperature was too low for significant nitrification to occur and so Didin had only a minor effect (Maidl and Fischbeck 1989). This conclusion is supported by the fact that, during the first leaching period, leaching of nitrate ni- trogen from lysimeters fertilized with livestock manure was rather small. Didin, however, seemed to have a positive effect on the recovery of nitrogen in barley. and lowest in treatment with manure in Decem- ber. The differences between treatments are mainly ascribed to differences in ammonia vol- atilization. December was an especially poor spreading timebecause manure could not be in- corporated into the frozen soil. September was better because the manure was mixed into the soil shortly after spreading. In May, manure was left on the soil surface for three days before it was incorporated; the delay is reflected in the N recovery data. The effect of spreading time on the leaching of total nitrogen, nitrate nitrogen, ammonium nitrogen and organic nitrogen was clearly dem- onstrated. Nitrogen leaching was lowest from the spring application and highest from applications in September. These results are consistent with those reported in the literature (Vetter and Stef- fens 1977, 1981, Brink and Jernlås 1982, Dijk 1985, Ivarsson and Brink 1985, Brink 1987, Görlitz 1989,Torstensson 1992). Didin did not have a significant effect on ni- trogen leaching. This was surprising because several studies have shown that Didin is very Kemppainen, E.: Leaching and uptake ofnitrogen and phosphorus... NJF Utredninger-Rapporter74: 97-101. Steenvoorden, J. H. A. M. & Oosterom, H. P. 1981. Natural and artificial sources of nitrogen and phosphate pollution of surface waters in the Netherlands. Nitrogen Losses and Surface Run-off from Landspreading of Ma- nures. p. 307-333. The Hague. -1989a. Effect of Didin (Dicyandiamide) on the fertilizer value of cow slurry for barley. Annales Agriculturae Fen- niae 28: 133-150. -1989b. Nutrient content and fertilizer value of livestock manure with special reference to cow manure. Annales Agriculturae Fenniae 28: 163-284. Torstensson, G. 1992. Kväveutlakning i storruteförsök med stallgödsel. Hudyrgödning, Resurse - Miljö. NJF Utredninger-Rapporter74: 97-101. -1989b. Nutrient content and fertilizer value of livestock manure with special reference to cow manure. Annales Agriculturae Fenniae 28: 163-284. Kjellerup, V. 1986. Nitrogen effect of slurry mixed with nitrification inhibitors: field experiments. Efficient Land Use of Sludge and Manure, p. 2-6. London. Kjellerup, V. 1986. Nitrogen effect of slurry mixed with nitrification inhibitors: field experiments. Efficient Land Use of Sludge and Manure, p. 2-6. London. Tveitnes, S. & Håland, Å. 1989. Influence of the nitrifi- cation inhibitor Dicyandiamide (DCD) on the nitrogen ef- ficiency of cattle slurry. Norwegian Journal of Agricultur- al Sciences 3: 343-350. Maldl, F. X. & Fischbeck, G. 1989. Effects of Long-term Applications of Slurry on Soil Nitrogen Mineralization. Journalof Agronomy and Crop Science 162: 310-319. Uhlen, G. & Österud, J. G. 1992. Nitrogen, fosfor og kalium i gröftevannspröver fra dyrket mark. Norsk Land- bruksforskning 6: 61-72. Meissner, R., Kramer, D., Taeger, H. & Schonert, P. 1991. Lysimeterversuchsergebnisse über die Wirkung der Nitrifizide “Dicyandiamid” (DCD) und “1-Carbamoyl-3(5)- methylpyrazol” (CMP), Archiv fur Acker- und Pflanzen- bau und Bodenkunde 35: 411-423. Vetter, H. & Steffens, G. 1977. Der Einfluss gestaffelter Gullemengenund verschiedener Dungungszeitpunkte auf die Nährstoffverlagerung in tiefere Bodenschichten und in das Wasser. Landwirtschafliche Forschung, Sonder- heft 34: 238-246. Melanen, M., Jaakkola, A., Melkas, M., Ahtiainen, M. & Matinvesi, J. 1985. Leaching resulting from land ap- plication of sewage sludge and slurry. Vesientutkimus- laitoksen julkaisuja 61. 124 p. Niinioja, R. 1993. Lietelannan levitys ja ravinteiden huuh- toutuminen. Summary: Leaching of nutrients from land application of slurry. Publications of the Water and Envi- ronment Administration. A 150: 1-87. Melanen, M., Jaakkola, A., Melkas, M., Ahtiainen, M. & Matinvesi, J. 1985. Leaching resulting from land ap- plication of sewage sludge and slurry. Vesientutkimus- laitoksen julkaisuja 61. 124 p. - & Steffens, G. 1981. Nährstoffverlagerung und Nähr- stoffeintrag in das oberflachennahe Grundwasser nach Gulledungung. References kvåve, fosfor och kalium från åker. Ekohydrologi 4/79: 7-57. kvåve, fosfor och kalium från åker. Ekohydrologi 4/79: 7-57. Alexander, M. 1991. Introduction to Soil Microbiology. 2nd ed. Malabar, Florida. 467 p. - & Jernlås, R. 1982. Utlakning vid spridning höst och vår av flytgödsel. Ekohydrologi 12/82: 3-14. Amberger, A. 1981. Dicyandiamid (“Didin”) als Nitrifika- tionshemmstoff. Bayerisches Landwirtschaftliches Jahr- buch 7/81: 845-853. Dijk, T. A. van. 1985. De uitspoeling van mineralen op bouwland waaraan jaarlijks drijfmest wordt toegediend. Summary: Leaching of plant nutrients from arable land as affected by annual applications of cattle slurry. Insti- tuut voor Bodemvruchtbaarheid. Rapport 2/85. p. 1-61. Dijk, T. A. van. 1985. De uitspoeling van mineralen op bouwland waaraan jaarlijks drijfmest wordt toegediend. Summary: Leaching of plant nutrients from arable land as affected by annual applications of cattle slurry. Insti- tuut voor Bodemvruchtbaarheid. Rapport 2/85. p. 1-61. Eder, G. 1985. Der Einfluss steigender Gullegaben auf den Boden, den Pflanzenertrag, die Futterqualität und das Sickerwasser. Veröffentlichungen der Bundesanstalt fur alpenländischeLandwirtschaft, Gumpenstein. Heft 3: 1-19. - 1989. Research on dicyandiamide as a nitrification in- hibitor and future outlook. Communications in Soil Sci- ence and Plant Analysis 20: 1933-1955. -1991. Slurry fertilization with the aim of low nitrate leach- ing. Recent Developments in Animal Waste Utilization. FAO. REUR Technical Series 17: 223-225. Eder, G. 1985. Der Einfluss steigender Gullegaben auf den Boden, den Pflanzenertrag, die Futterqualität und das Sickerwasser. Veröffentlichungen der Bundesanstalt fur alpenländischeLandwirtschaft, Gumpenstein. Heft 3: 1-19. Asmus, F. 1989. Untersuchungen zur Reduzierung der N-Verlagerung nach Gulledungung in Sand-Rosterde. Asmus, F. 1989. Untersuchungen zur Reduzierung der N-Verlagerung nach Gulledungung in Sand-Rosterde. Archiv fur Acker- und Pflanzenbau und Bodenkunde 33: 573-579. Archiv fur Acker- und Pflanzenbau und Bodenkunde 33: 573-579. Görlitz, H. 1989. Verringerung der N-Verlagerung im Boden nach Gulledungung durch Einsatz von Nitrifika- tionsinhibitoren - Ergebnisse aus Lysimeteruntersuchun- gen. Archivfur Acker- und Pflanzenbau und Bodenkunde 33: 567-572. Bartels, R. & Scheffer, B. 1987. Limitations for slurry application to peat grassland. Animal Manure on Grass- land and Fodder Crops. Fertilizer or Waste? p. 365-367. Dordrecht. Brink, N. 1987. Kväve och fosfor från stallgödslad åker. Ekohydrologi 24/87: 38-39. -1990. Gulleeinsatz mit Nitrifikationsinhibitoren im Herbst zu Wintergetreide. Agrobiological Research 43, 3: 253- 259. -, Gustafson, A. & Persson, G. 1979. Förluster av 373 Kemppainen, E.: Leaching and uptake ofnitrogen and phosphorus... Nilsson, L. G. 1991. Nitrifikationshämmare - flytgödsel. Sveriges Lantbruksuniversitet. Institutionen för Markve- tenskap. Rapport 181: 1-28. Asmus, F., Völker, U., Benthin, K. & Muller, H. 1988. Verminderung der Stickstoffauswaschung nach Gulledun- gung durch Einsatz von Nitrifikationsinhibitoren und Kom- bination mit Strohdungung. Zentralblatt fur Mikrobiologie 143: 323-330. Pain, B. F., Thompson, R. 8., De la Lande Cremer, L. C. N. & Ten Moite, L. 1987. The use of additives in live- Pain, B. F., Thompson, R. 8., De la Lande Cremer, L. C. N. & Ten Moite, L. 1987. The use of additives in live- stock slurries to improve their flow properties, conserve nitrogen and reduce odours. Animal Manure on Grass- land and Fidder Crops. Fertilizer or Waste? p. 229-246. Dordrecht. Herrmann,V., Görlltz, H. & Asmus, F. 1983. Lysimeter- untersuchungen zur Nährstoffverlagerungnach Gulledun- gung in einer Sand-Rosterde - Phosphor, Kalium und Magnesium. Archiv fur Acker- und Pflanzenbau und Bo- denkunde 27: 687-692. Pedersen, J. B. 1991. Forurening fra pelsdyrfarme. Miljöstyrelsen (Danmark). Miljöprojekt nr. 163: 1-96. Pedersen, J. B. 1991. Forurening fra pelsdyrfarme. Miljöstyrelsen (Danmark). Miljöprojekt nr. 163: 1-96. SAS Institute 1985. SAS User’s Guide: Statistics, Ver- sion 5 Edition. Gary, NC. 956 p. Ivarsson, K. & Brink, N. 1985. Utlakning från en grov- mojord i Halland. Ekohydrologi 20/85: 13-25. SAS Institute 1985. SAS User’s Guide: Statistics, Ver- sion 5 Edition. Gary, NC. 956 p. Jaakkola, A. & Yläranta, T. 1985. Typen huuhtoutumi- nen jahyväksikäyttö lysimetrikokeessa. Summary: Leach- ing of nitrogen and its utilization by plants in lysimeters, SITRA. Nitrogen project. Julkaisu 22: 1-38. Scheffer, B. von, Kuntze, H. & Bartels, R. 1981. Zum Phosphataustrag aus mit Guile gediingtem Hochmoor- boden. Landwirtschafliche Forschung, Sonderheft 40: 288-296. Kähäri, J. & Nissinen, H. 1978. The mineral element contents of timothy (Phleum pratense) in Finland. I. Acta Agriculturae Scandinavica, Supplement 20: 26-39. Stauffer, W. & Enggist, A. 1990. Einfluss von Gulleaus- bringtermin, Kultur und Wiesenumbruch auf die Nitrat- auswaschung in einem Lysimeterversuch. Landwirtschaft Schweiz 3,7: 373-379. Kemppainen, E. 1984. Karjanlannan ravinnepitoisuus ja syyt sen vaihteluun. Summary: The nutrient content of livestock manure and the causes of its variation. SITRA. Nitrogen project. Julkaisu 11: 1-80. Steenvoorden, J. H. A. M. & Oosterom, H. P. 1981. Natural and artificial sources of nitrogen and phosphate pollution of surface waters in the Netherlands. Nitrogen Losses and Surface Run-off from Landspreading of Ma- nures. p. 307-333. The Hague. Torstensson, G. 1992. Kväveutlakning i storruteförsök med stallgödsel. Hudyrgödning, Resurse - Miljö. Kemppainen, E.: Leaching and uptake ofnitrogen and phosphorus... Zeitschrift fur Kulturtechnik und Flur- bereinigung 22: 159-172, Vuorinen, J. & Mäkitie, 0.1955. The method of soil test- ing in use in Finland. Agrogeological Publications 63: 1- 44. 374 SELOSTUS Naudan lietelannan ja ketun lannan typen ja fosforin huuhtoutuminen ja hyväksikäyttö lysimetrikokeessa Erkki Kemppainen Maatalouden tutkimuskeskus Lysimetrikokeessa tutkittiin maalajin, levitysajan sekä nitrifikaatioinhibiittorin(Didin) vaikutusta nau- dan lietelannan ja ketun lannan typen ja fosforin huuhtoutumiseen ja hyväksikäyttöön. tui vähiten toukokuussa levitetystä lannasta. Didin ei vähentänyt typen huuhtoutumista merkitsevästi. Ke- tun lannasta huuhtoutui turvemaalla selvästi enem- män fosforia kuin naudan lietelannasta. Lannan le- vitysaika ei vaikuttanut fosforin huuhtoutumiseen. Valunta ja kokonaistypen huuhtoutuminen turve- maasta olivat noin kaksinkertaisia hietaan verrattu- na. Nitraattitypen huuhtoutumisessa ei ollut merkit- tävää eroa, mutta amraoniumtyppeä turvemaasta huuhtoutui 50-kertainen määrä ja orgaanista typpeä 3-kertainen määrä hietaan verrattuna. Turvemaasta huuhtoutui myös kokonaisfosforia 23-kertainen mää- rä ja liukoista fosforia 39-kertainen määrä hietaan verrattuna. Turvemaa tuotti huomattavasti suurempia ohrasa- toja kuin hieta. Ketun lanta oli selvästi naudan liete- lantaa tehokkaampaa lannoitetta. Ensimmäisenä koe- vuonna lannan levitys joulukuussa vähensi merkitse- västi sen lannoitusvaikutusta muihin levitysaikoihin verrattuna. Ohran jyvä- ja olkisadon perusteella las- kettuna lannan kokonaistypen näennäinen hyväksi- käyttö oli 24-41 % ja lannan fosforin hyväksikäyttö 6-51 %. Lannan kokonaistypestä huuhtoutui 4-21 % ja fosforista 0-2,6 %. Naudan lietelannasta ja ketun lannasta huuhtou- tui suunnilleen yhtä paljon typpeä. Typpeä huuhtou- 375
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Agroecological Certification of Farm Land of Agricultural Enterprises TzOV «Zhyva Zemlia Potutory» and TOV «Krona» in Ternopil region, Berezhany District
Naukovij vìsnik Lʹvìvsʹkogo nacìonalʹnogo unìversitetu veterinarnoï medicini ta bìotehnologìj ìmenì S.Z. G̀žicʹkogo
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Citation: Pavliv, A.V., Pavliv, O.V. (2017). Agroecological Certification of Farm Land of Agricultural Enterprises TzOV «Zhyva Zemlia Potutory» and TOV «Krona» in Ternopil region, Berezhany District. Scientific Messenger LNUVMBT named after S.Z. Gzhytskyj, 19(74), 196–202. 1Национальный университет биоресурсов и природопользования Украины, ул. Героев Обороны, 11, Киев, 03041, Украина; 2Обособленное подразделение Национального университета биоресурсов и природопользования Украины «Бережанский агротехнический институт», ул. Академическая 20, г. Бережаны, 47501, Украина Scientific Messenger LNUVMBT named after S.Z. Gzhytskyj, 2017, vol. 19, no 74 Агроекологічна оцінка земель сільськогосподарських підприємств Тернопільської області Бережанського району ТзОВ «Жива Земля Потутори» та ТОВ «Крона»  А.В. Павлів1, О.В. Павлів2 pavliv–1978@ukr.net 1Національний університет біоресурсів і природокористування України, вул. Героїв Оборони, 11, м. Київ, 03041, Україна; 2Відокремлений підрозділ Національного університету біоресурсів та природокористування України «Бережанський агротехнічний інститут», вул. Академічна 20, м. Бережани, 47501, Україна 1Національний університет біоресурсів і природокористування України, вул. Героїв Оборони, 11, м. Київ, 03041, Україна; 2Відокремлений підрозділ Національного університету біоресурсів та природокористування України «Бережанський агротехнічний інститут», вул. Академічна 20, м. Бережани, 47501, Україна Проведено агроекологічну оцінку земель для вирощування сільськогосподарських культур підприємств ТзОВ «Жива Земля Потутори» с. Потутори Бережанського району Тернопільської області та ТОВ «Крона» с. Жуків Бережанського району Тернопільської області за еколого-агрохімічними показниками. В статті охарактеризовано ґрунтовий покрив за потужністю гумосового шару, вмістом гумусу, азоту (що легко гідролізується), рухомого фосфору, обмінного калію, за сумою активних температур вищою 10 °С, гідротермічним коефіцієнтом, рівнем ґрунтових вод, вмістом рухомих форм важких металів: Кадмію, Свинцю, Ртуті, а також кислотність ґрунту (обмінна, рH сольове). Досліджено динаміку показників основних еко- лого-агрохімічних властивостей та щільність забруднення темно-сірих опідзолених ґрунтів. Проаналізувавши показники агрохімічного стану грунту земель сільськогосподарських підприємств ТзОВ «Жива Земля Потутори» с. Потутори Бере- жанського району Тернопільської області та ТОВ «Крона» с. Жуків Бережанського району Тернопільської області, встанов- лено, що ґрунти мають оптимальні, допустимі (задовільні) умови для вирощування зернових, технічних, кормових культур та отримання повноцінних врожаїв сільськогосподарських культур. Лімітуючим фактором виступає низька забезпеченість сполуками азоту, що легко гідролізується на земельних ділянках підприємств ТзОВ «Жива Земля Потутори» с. Потутори Бережанського району Тернопільської області та ТОВ «Крона» с. Жуків Бережанського району Тернопільської області щодо вирощування зернових, технічних, кормових культур, тобто дані умови – недопустимі (погані). Ключові слова: агроекологічна оцінка, агрохімічні показники, ґрунт, клімат, вміст елементів живлення, вміст гумусу, Ка- дмію, Свинцю, Ртуті, кислотність, зернові, технічні та кормові культури. Агроэкологическая оценка земель сельскохозяйственных предприятий Тернопольской области Бережанского района ООО «Живая Земля Потуторы» и ООО «Крона» А.В. Павлив1, О.В. Павлив2 pavliv–1978@ukr.net Науковий вісник ЛНУВМБТ імені С.З. Ґжицького, 2017, т 19, № 74 Науковий вісник ЛНУВМБТ імені С.З. Ґжицького, 2017, т 19, № 74 Науковий вісник ЛНУВМБТ імені С.З. Ґжицького, 2017, т 19, № 74 Науковий вісник ЛНУВМБТ імені С.З. Ґжицького, 2017, т 19, № 74 Проведено агроэкологическую оценку земель для выращивания сельскохозяйственных культур предприятий ООО «Жи- вая Земля Потуторы» с. Потуторы Бережанского района Тернопольской области и ООО «Крона» с. Жуков Бережанского района Тернопольской области за эколого-агрохимическим показателям. В статье охарактеризованы почвенный покров по мощности гумосового слоя, содержанию гумуса, азота (легко гидролизуется), подвижного фосфора, обменного калия, по сумме активных температур выше 10 °С, гидротермическому коэффициенту, уровню грунтовых вод, содержанию подви- жных форм тяжелых металлов: Кадмия, Свинца, Ртути, а также кислотность почвы (обменная, рН солевое). Исследова- на динамика показателей основных эколого-агрохимических свойств и плотность загрязнения темно-серых оподзоленных почв. Проанализировав показатели агрохимического состояния почвы земель сельскохозяйственных предприятий ООО «Живая Земля Потуторы» с. Потуторы Бережанского района Тернопольской области и ООО «Крона» с. Жуков Бережан- ского района Тернопольской области, установлено, что почвы имеют оптимальные, допустимые (удовлетворительные) условия для выращивания зерновых, технических, кормовых культур и получения полноценных урожаев сельскохозяйствен- ных культур. Лимитирующим фактором выступает низкая обеспеченность соединениями азота, легко гидролизуется на земельных участках предприятий ООО «Живая Земля Потуторы» с. Потуторы Бережанского района Тернопольской области и ООО «Крона» с. Жуков Бережанского района Тернопольской области по выращиванию зерновых, технических, кормовых культур, то есть данные условия – недопустимы (плохие). Ключевые слова: агроэкологическая оценка, агрохимические показатели, почва, климат, содержание элем я, содержание гумуса, Кадмия, Свинца, Ртути, кислотность, зерновые, технические и кормовые культуры. Agroecological Certification of Farm Land of Agricultural Enterprises TzOV «Zhyva Zemlia Potutory» and TOV «Krona» in Ternopil region, Berezhany District A.V. Pavliv1, O.V. Pavliv2 pavliv–1978@ukr.net 1National University of life and environmental sciences of Ukraine, Heroyiv Oborony Str., 11, Kyiv, 03041, Ukraine 2Separated subdivision of the National University of Life and Environmental Sciences of Ukraine «Berezhansky Agricultural Institute» Academichna Str., 20, Berezhany, 4750 ,Ukraine 1National University of life and environmental sciences of Ukraine, Heroyiv Oborony Str., 11, Kyiv, 03041, Ukraine 2Separated subdivision of the National University of Life and Environmental Sciences of Ukraine «Berezhansky Agricultural Institute» Academichna Str., 20, Berezhany, 4750 ,Ukraine The agroecological assessment of land for growing crops according to agrochemical rates has been conducted at TzOV «Zhyva Zemlia Potutory» in Potutory village, Berezhany district, Ternopil region and TOV «Krona» in Zhukiv village , Berezhany district, Ternopil region. The article describes the mantle of soil in thickness of humus layer, content of humus, nitrogen (which is easily hydrolysed), labile phosphorus, exchange potassium, at the sum of active temperatures above 10 °C, hydrothermal index, groundwa- ter level, the content of mobile forms of heavy metals: cadmium, lead, mercury and acidity of soil (metabolic, pH saline). The dy- namics of the main indicators of ecological and agrochemical properties and density of contamination of dark gray podzolized soils. Having analysed the agroecological condition of soil at farm land of TzOV «Zhyva Zemlia Potutory» in Potutory village, Berezhany district, Ternopil region and TOV «Krona» in Zhukiv village, Berezhany district, Ternopil region. It has been stated that the soils have optimal, acceptable (satisfactory) conditions for growing grain, industrial, forage crops and for obtaining valuable crop yields. Limiting factors are low availability of nitrogen compounds that are easily hydrolysed and concerning grain, industrial, forage crops these conditions are unacceptable (poor) at farmland of TzOV «Zhyva Zemlia Potutory» in Potutory village, Berezhany district, Ternopil region and TOV «Krona» in Zhukiv village, Berezhany district, Ternopil region. Key words: ahroekolohycheskaya coments, ahrohymycheskye indicators, soils, climate, pover elements content, content humus kadmya, lead, mercury, acidity, cereal, tehnycheskye kormovue and culture. Scientific Messenger LNUVMBT named after S.Z. Gzhytskyj, 2017, vol. 19, no 74 Агроэкологическая оценка земель сельскохозяйственных предприятий Тернопольской области Бережанского района ООО «Живая Земля Потуторы» и ООО «Крона» А.В. Павлив1, О.В. Павлив2 pavliv–1978@ukr.net А.В. Павлив1, О.В. Павлив2 pavliv–1978@ukr.net 196 Науковий вісник ЛНУВМБТ імені С.З. Ґжицького, 2017, т 19, № 74 Матеріал і методи досліджень Об’єкт досліджень – агроекологічне оцінювання земель. Предмет – землі сільськогосподарських підп- риємств ТзОВ «Жива Земля Потутори» с. Потутори Бережанського району Тернопільської області та ТОВ «Крона» с. Жуків Бережанського району Тернопіль- ської області, які представлені темно-сірими опідзо- леними ґрунтами. Агроекологічна оцінка земель проводилась згідно з методикою В.В.Медведєва, розробленою в Інституті грунтознавства та агрохімії ім. О.Н. Соколовського УААН (Medvedeva, 1997), в основі якої лежать три рівні опису умов: 1 – оптимальні умови; 2 – допусти- мі (задовільні); 3 – недопустимі (погані) умови. Пер- ший рівень відповідає таким умовам, за яких можли- во отримати найбільші екологічно чисті врожаї, за другим рівнем є загроза зниження врожайності на 23– 30, за третім рівнем – до 50%. В основу її покладено принцип екологічного співвідношення параметрів довкілля (грунт, клімат), що характеризують потреби сільськогосподарських культур до їхнього вирощу- вання. Оцінку земель проводили з використанням показ- ників за чинними методиками та ДСТУ: - гумус за методом Тюріна в модифікації Симако- вої (ДСТУ 4289:2004); - рухомий Фосфор і обміний Калій за методом Чи- рікова (ДСТУ – 4115-2002); - вміст лужногідролізованого азоту – за методом Корнфілда; Виходячі з таблиць 1, 2, можна сказати, що допус- тимі умови для вирощування зернових, технічних та кормових культур за потужністю гумосового шару (перебувають у межах від 35–45 см) сформувалися на всіх досліджуваних полях (табл. 3–8). - ступінь кислотності (рH) – потенціометрично за методом ЦІНАО (ГОСТ 26483-85). - ступінь кислотності (рH) – потенціометрично за методом ЦІНАО (ГОСТ 26483-85). - вміст рухомих форм: Кадмію, Свинцю, Ртуті – інверсійно-хронопотенціометричний метод; Таблиця 1 Таблиця 1 Таблиця 1 Дані агроекологічної оцінки ґрунтового покриву земель ТзОВ «Жива Земля Потутори» с. Потутори № поля Показники Потужність гуму- сового шару, см Реакція ґрунтово- го розчину, рНсол. Вміст в орному шарі гумусу, % Вміст азоту, що легко гідролізу- ється, мг/кг Вміст рухомого фосфору, мг/кг Вміст обмінного калію, мг/кг Сума активних температур вище 10 °С. Вступ їх раціональне використання в кінцевому підсумку визначають рівень добробуту суспільства (Broshchak, 2013). Цінність землі як основного засобу сільськогоспо- дарського виробництва у конкретній сільськогоспо- дарській інфраструктурі визначається родючість ґру- нтів. Саме родючість ґрунтів зумовлює рівень проду- ктивності земель, їхню господарську значущість і вартість. Україна – одна з не багатьох держав світу, котра володіє величезним резервом родючих грунтів, тому вона має бути одним зі світових лідерів вироб- ництва високоякісних продуктів харчування. Ґрунто- вий покрив основне загальнонаціональне багатство нашої країни і головний засіб виробництва в сільсь- кому господарстві. Актуальність теми: Основна властивість грунтів – їх родючість, яка залежить від багатьох факторів: склад ґрунту, його фізичних, хімічних, фізико- хімічних і біологічних властивостей. Землі сільсько- господарського використання зазнали відчутної де- градації, серед багатьох причин якої є надзвичайно висока розораність, ерозія, погіршення реакції та со- льового режиму ґрунтового середовища, забруднення їх важкими металами, радіонуклідами, пестицидами та іншими токсинами тощо. Тому дослідження агрое- кологічного стану земель є на сьогодні актуальним, щоб цілеспрямовано керувати формуванням урожаю, ростом і розвитком рослин. Ґрунтовий покрив основне загальнонаціональне багатство нашої країни і головний засіб виробництва в сільському господарстві. Якість земельних ресурсів, Scientific Messenger LNUVMBT named after S.Z. Gzhytskyj, 2017, vol. 19, no 74 197 Scientific Messenger LNUVMBT named after S.Z. Gzhytskyj, 2017, vol. 19, no 74 197 Науковий вісник ЛНУВМБТ імені С.З. Ґжицького, 2017, т 19, № 74 Результати та їх обговорення Мета і завдання дослідження: Територіальним об’єктом досліджень є Бережанський район Терно- пільської області. Мета – оцінити агроекологічний стан земель та параметри довкілля (ґрунт, клімат), що характеризують потреби сільськогосподарських куль- тур до їхнього вирощування. Важливе значення в народному господарстві сьо- годні, належить вирощуванню сільськогосподарських культур та отриманню високоякісних врожаїв та си- ровини. Агроекологічну оцінку грунтового покриву проводили з метою вирощування зернових, технічних та кормових культур. Земельні ділянки розташовані в межах населених пунктів с. Потутори Бережанського району Тернопільської області та ТОВ «Крона» с. Жуків Бережанського району Тернопільської обла- сті. У земельному фонді попередньо згаданих госпо- дарств переважають темно-сірі опідзолені ґрунти. Обстеження ґрунтів в господарстві ТзОВ «Жива Зем- ля Потутори» проведено на площі 309,6 гектарів, а в господарстві ТОВ «Крона» проведено на площі 148,8 гектарів (Patyka and Tarariko, 2002). Провести агроекологічну оцінку земель сільсько- господарських підприємств ТзОВ «Жива Земля Поту- тори» с. Потутори Бережанського району Тернопіль- ської області та ТОВ «Крона» с. Жуків Бережанського району Тернопільської області для вирощування зернових, технічних та кормових культур за еколого- агрохімічними показниками. Scientific Messenger LNUVMBT named after S.Z. Gzhytskyj, 2017, vol. 19, no 74 Матеріал і методи досліджень Гідротермічний коефіцієнт Рівень ґрунтових вод (РГВ), м Вміст рухомих форм важких мета- лів (мг/кг): кадмію свинцю ртуть Рілля 1 25–40 6,0 2,90 114 117 106 2550 1,4 8 0,09 1,26 0 2 25–40 5,4 2,15 108 80 136 2550 1,4 8 0,08 0,69 0 3 25–40 6,1 3,04 125 144 134 2550 1,4 8 0,09 1,4 0 4 25–40 6,3 2,46 109 185 134 2550 1,4 8 0,1 1,27 0 Таб Дані агроекологічної оцінки ґрунтового покриву земель ТОВ «Крона» с.Жуків Показники Таблиця 3 Дані агроекологічної оцінки ґрунтового покриву земель для вирощування зернових культур ТзОВ «Жива Земля Потутори» № поля Показники Потужність гумусового шару, см Реакція ґрунтового розчину, рНсол. Вміст в орному шарі гумусу, % Вміст азоту, що легко гідролізується, мг/кг Вміст рухомого фосфо- ру, мг/кг Вміст обмінного калію, мг/кг Сума активних температур вище 10 °С Гідротермічний коефіці єнт Рівень ґрунтових вод (РГВ), м Вміст рухомих форм важких металів (мг/кг): кадмію свинцю ртуть Рілля 1 Д О Д Н Д О О О О О Д О 2 Д О Д Н Д О О О О О Д О 3 Д О Д Н О О О О О О Д О 4 Д О Н Н Д О О О О О Д О 5 Д О Д Н Д О О О О О Д О 6 Д О Д Н Д О О О О О Д О 7 Д О Д Н Н О О О О О Д О 9 Д О Д Н Н О О О О О Д О 16 Д О Д Н Н О О О О О Д О Культурне пасовище 12 Д О Д Н Д Д О О О О Д О 13 Д О Д Н О Д О О О О Д О * О – оптимальні умови; Д – допустимі умови; Н – недопустимі умови (згідно класифікації В.В. Медведєва). Таблиця 4 Дані агроекологічної оцінки ґрунтового покриву земель для вирощування зернових культур ТОВ «Крона» № поля Показники Потужність гумусового шару, см Реакція ґрунтового розчину, рНсол. Вміст в орному шарі гумусу, % Вміст азоту, що легко гідролізується, мг/кг Вміст рухомого фосфору, мг/кг Вміст обмінного калію, мг/кг Сума активних темпера- тур вище 10 °С. Матеріал і методи досліджень Гідротермічний коефіцієнт Рівень ґрунтових вод (РГВ), м Вміст рухомих форм важких металів (мг/кг): кадмію свинцю ртуть Рілля 1 Д О Д Н О Д О О О О Д О 2 Д О Д Н Д О О О О О Д О 3 Д О Д Н О О О О О О Д О 4 Д О Д Н О О О О О О Д О * О – оптимальні умови; Д – допустимі умови; Н – недопустимі умови (згідно класифікації В.В. Медведєва). Таблиця 3 Дані агроекологічної оцінки ґрунтового покриву земель для вирощування зернових культур ТзОВ «Жива Земля Потутори» № поля Показники Потужність гумусового шару, см Реакція ґрунтового розчину, рНсол. Вміст в орному шарі гумусу, % Вміст азоту, що легко гідролізується, мг/кг Вміст рухомого фосфо- ру, мг/кг Вміст обмінного калію, мг/кг Сума активних температур вище 10 °С Гідротермічний коефіці єнт Рівень ґрунтових вод (РГВ), м Вміст рухомих форм важких металів (мг/кг): кадмію свинцю ртуть Рілля 1 Д О Д Н Д О О О О О Д О 2 Д О Д Н Д О О О О О Д О 3 Д О Д Н О О О О О О Д О 4 Д О Н Н Д О О О О О Д О 5 Д О Д Н Д О О О О О Д О 6 Д О Д Н Д О О О О О Д О 7 Д О Д Н Н О О О О О Д О 9 Д О Д Н Н О О О О О Д О 16 Д О Д Н Н О О О О О Д О Культурне пасовище 12 Д О Д Н Д Д О О О О Д О 13 Д О Д Н О Д О О О О Д О * О – оптимальні умови; Д – допустимі умови; Н – недопустимі умови (згідно класифікації В.В. Медведєва). Т б 4 Табл ані агроекологічної оцінки ґрунтового покриву земель для вирощування зернових культур ТзОВ «Жива Земля Потутори» Таблиця 4 Дані агроекологічної оцінки ґрунтового покриву земель для вирощування зернових культур ТОВ «Крона» № поля Показники Потужність гумусового шару, см Реакція ґрунтового розчину, рНсол. Вміст в орному шарі гумусу, % Вміст азоту, що легко гідролізується, мг/кг Вміст рухомого фосфору, мг/кг Вміст обмінного калію, мг/кг Сума активних темпера- тур вище 10 °С. Матеріал і методи досліджень Гідротермічний коефіцієнт Рівень ґрунтових вод (РГВ), м Вміст рухомих форм важких металів (мг/кг): кадмію свинцю ртуть Рілля 1 25–40 6,3 2,35 133 74 123 2550 1,4 7 0,14 1,78 0 2 25–40 6,4 2,48 124 62 120 2550 1,4 7 0,12 1 0 3 25–40 6,6 2,40 138 113 131 2550 1,4 7 0,08 1,49 0 4 25–40 6,3 1,86 136 77 145 2550 1,4 7 0,1 1,53 0 5 25–40 6,4 2,24 130 80 165 2550 1,4 7 0,09 1,47 0 6 25–40 5,4 2,40 144 57 161 2550 1,4 7 0,11 1,5 0 7 25–40 5,8 2,34 125 38 158 2550 1,4 7 0,07 1,69 0 9 25–40 6,2 2,00 144 35 143 2550 1,4 7 0,09 1,86 0 16 25–40 6,0 2,35 85 40 111 2550 1,4 7 0,39 1,75 0 Культурне пасовище 12 25–40 7,0 2,85 99 74 70 2550 1,4 7 0,1 1,95 0 13 25–40 6,9 2,72 132 109 105 2550 1,4 7 0,24 1,29 0 ц Дані агроекологічної оцінки ґрунтового покриву земель ТзОВ «Жива Земля Потутори» с. Потутори Scientific Messenger LNUVMBT named after S.Z. Gzhytskyj, 2017, vol. 19, no 74 198 Науковий вісник ЛНУВМБТ імені С.З. Ґжицького, 2017, т 19, № 74 Таблиця 2 Дані агроекологічної оцінки ґрунтового покриву земель ТОВ «Крона» с.Жуків № поля Показники Потужність гуму- сового шару, см Реакція ґрунтового розчину, рНсол. Вміст в орному шарі гумусу, % Вміст азоту, що легко гідролізуєть- ся, мг/кг Вміст рухомого фосфору, мг/кг Вміст обмінного калію, мг/кг Сума активних температур вище 10 °С. Гідротермічний коефіцієнт Рівень ґрунтових вод (РГВ), м Вміст рухомих форм важких мета- лів (мг/кг): кадмію свинцю ртуть Рілля 1 25–40 6,0 2,90 114 117 106 2550 1,4 8 0,09 1,26 0 2 25–40 5,4 2,15 108 80 136 2550 1,4 8 0,08 0,69 0 3 25–40 6,1 3,04 125 144 134 2550 1,4 8 0,09 1,4 0 4 25–40 6,3 2,46 109 185 134 2550 1,4 8 0,1 1,27 0 Таблиця 3 Дані агроекологічної оцінки ґрунтового покриву земель для вирощування зернових культур ТзОВ «Жива Земля Потутори» № поля Показники Потужність гумусового шару, см Реакція ґрунтового розчину, рНсол. Scientific Messenger LNUVMBT named after S.Z. Gzhytskyj, 2017, vol. 19, no 74 Матеріал і методи досліджень Вміст в орному шарі гумусу, % Вміст азоту, що легко гідролізується, мг/кг Вміст рухомого фосфо- ру, мг/кг Вміст обмінного калію, мг/кг Сума активних температур вище 10 °С Гідротермічний коефіці єнт Рівень ґрунтових вод (РГВ), м Вміст рухомих форм важких металів (мг/кг): кадмію свинцю ртуть Рілля 1 Д О Д Н Д О О О О О Д О 2 Д О Д Н Д О О О О О Д О 3 Д О Д Н О О О О О О Д О 4 Д О Н Н Д О О О О О Д О 5 Д О Д Н Д О О О О О Д О 6 Д О Д Н Д О О О О О Д О 7 Д О Д Н Н О О О О О Д О 9 Д О Д Н Н О О О О О Д О 16 Д О Д Н Н О О О О О Д О Культурне пасовище 12 Д О Д Н Д Д О О О О Д О 13 Д О Д Н О Д О О О О Д О * О – оптимальні умови; Д – допустимі умови; Н – недопустимі умови (згідно класифікації В.В. Медведєва). Таблиця 4 Дані агроекологічної оцінки ґрунтового покриву земель для вирощування зернових культур ТОВ «Крона» № поля Показники ужність гумусового шару, см еакція ґрунтового розчину, рНсол. міст в орному шарі гумусу, % іст азоту, що легко дролізується, мг/кг Вміст рухомого фосфору, мг/кг Вміст обмінного калію, мг/кг а активних темпера- тур вище 10 °С. Гідротермічний коефіцієнт вень ґрунтових вод (РГВ), м міст рухомих форм ких металів (мг/кг): кадмію свинцю ртуть Таблиця 2 Таблиця 2 Дані агроекологічної оцінки ґрунтового покриву земель ТОВ «Крона» с.Жуків № поля Показники Потужність гуму- сового шару, см Реакція ґрунтового розчину, рНсол. Вміст в орному шарі гумусу, % Вміст азоту, що легко гідролізуєть- ся, мг/кг Вміст рухомого фосфору, мг/кг Вміст обмінного калію, мг/кг Сума активних температур вище 10 °С. Матеріал і методи досліджень Гідротермічний коефіцієнт Рівень ґрунтових вод (РГВ), м Вміст рухомих форм важких металів (мг/кг): кадмію свинцю ртуть Рілля 1 Д О Д Н О Д О О О О Д О 2 Д О Д Н Д О О О О О Д О 3 Д О Д Н О О О О О О Д О 4 Д О Д Н О О О О О О Д О * О – оптимальні умови; Д – допустимі умови; Н – недопустимі умови (згідно класифікації В.В. Медведєва). Scientific Messenger LNUVMBT named after S.Z. Gzhytskyj, 2017, vol. 19, no 74 199 Науковий вісник ЛНУВМБТ імені С.З. Ґжицького, 2017, т 19, № 74 Таблиця 5 Дані агроекологічної оцінки ґрунтового покриву земель для вирощування технічних культур ТзОВ «Жива Земля Потутори» № поля Показники Потужність гуму- сового шару, см Реакція ґрунтово- го розчину, рНсол. Вміст в орному шарі гумусу, % Вміст азоту, що легко гідролізу- ється, мг/кг Вміст рухомого фосфору, мг/кг Вміст обмінного калію, мг/кг Сума активних температур вище 10 °С Гідротермічний коефіцієнт Рівень ґрунтових вод (РГВ), м Вміст рухомих форм важких ме- талів (мг/кг): кад- мію свинцю ртуть Рілля 1 Д О Д Н Д О О О О О Д О 2 Д О Д Н Д О О О О О Д О 3 Д О Д Н О О О О О О Д О 4 Д О Н Н Д О О О О О Д О 5 Д О Д Н Д О О О О О Д О 6 Д О Д Н Н О О О О О Д О 7 Д О Д Н Н О О О О О Д О 9 Д О Д Н Н О О О О О Д О 16 Д О Д Н Н О О О О О Д О Культурне пасовище 12 Д О Д Н Д Д О О О О Д О 13 Д О Д Н Д Д О О О О Д О * О – оптимальні умови; Д – допустимі умови; Н – недопустимі умови (згідно класифікації В.В. Медведєва). Таблиця 6 Дані агроекологічної оцінки ґрунтового покриву земель для вирощування технічних культур ТОВ «Крона» № поля Показники Потужність гумусового шару, см Реакція ґрунто- вого розчину, рНсол. Матеріал і методи досліджень Вміст в орному шарі гумусу, % Вміст азоту, що легко гідролізу- ється, мг/кг Вміст рухомого фосфору, мг/кг Вміст обмінного калію, мг/кг Сума активних температур вище 10 °С Гідротермічний коефіцієнт Рівень ґрунтових вод (РГВ), м Вміст рухомих форм важких ме- талів (мг/кг): кад- мію свинцю ртуть Рілля 1 Д О Д Н Д О О О О О Д О 2 Д О Д Н Д О О О О О Д О 3 Д О Д Н О О О О О О Д О 4 Д О Н Н Д О О О О О Д О 5 Д О Д Н Д О О О О О Д О 6 Д О Д Н Н О О О О О Д О 7 Д О Д Н Н О О О О О Д О 9 Д О Д Н Н О О О О О Д О 16 Д О Д Н Н О О О О О Д О Культурне пасовище 12 Д О Д Н Д Д О О О О Д О 13 Д О Д Н Д Д О О О О Д О * О – оптимальні умови; Д – допустимі умови; Н – недопустимі умови (згідно класифікації В.В. Медведєва). Т б 6 Таблиця 5 Дані агроекологічної оцінки ґрунтового покриву земель для вирощування технічних культур ТзОВ «Жива Земля Потутори» Таблиця 6 Таблиця 6 Дані агроекологічної оцінки ґрунтового покриву земель для вирощування технічних культур ТОВ «Крона» № поля Показники Потужність гумусового шару, см Реакція ґрунто- вого розчину, рНсол. Вміст в орному шарі гумусу, % Вміст азоту, що легко гідролізу- ється, мг/кг Вміст рухомого фосфору, мг/кг Вміст обмінного калію, мг/кг Сума активних температур вище 10 °С Гідротермічний коефіцієнт Рівень ґрунто- вих вод (РГВ), м Вміст рухомих форм важких металів (мг/кг): кадмію свинцю ртуть Рілля 1 Д О Д Н О О О О О О Д О 2 Д О Д Н Д О О О О О О О 3 Д О О Н О О О О О О Д О 4 Д О Д Н О О О О О О Д О * О оптимальні умови; Д допустимі умови; Н недопустимі умови (згідно класифікації В В Медведєва) Д Д Д льні умови; Д – допустимі умови; Н – недопустимі умови (згідно класифікації В.В. Медведєва). Матеріал і методи досліджень Вміст в орному шарі гумусу, % Вміст азоту, що легко гідролізу- ється, мг/кг Вміст рухомого фосфору, мг/кг Вміст обмінного калію, мг/кг Сума активних температур вище 10 °С Гідротермічний коефіцієнт Рівень ґрунтових вод (РГВ), м Вміст рухомих форм важких ме- талів (мг/кг): кад- мію свинцю ртуть Рілля 1 Д О Д Н Д О О О О О Д О 2 Д О Д Н Д О О О О О Д О 3 Д О Д Н О О О О О О Д О 4 Д О Н Н Д О О О О О Д О 5 Д О Д Н Д О О О О О Д О 6 Д О Д Н Н О О О О О Д О 7 Д О Д Н Н О О О О О Д О 9 Д О Д Н Н О О О О О Д О 16 Д О Д Н Н О О О О О Д О Культурне пасовище 12 Д О Д Н Д Д О О О О Д О 13 Д О Д Н Д Д О О О О Д О * О – оптимальні умови; Д – допустимі умови; Н – недопустимі умови (згідно класифікації В.В. Медведєва). Таб иця 6 Таблиця 5 Дані агроекологічної оцінки ґрунтового покриву земель для вирощування технічних культур ТзОВ «Жива Земля Потутори» Таблиця 5 Дані агроекологічної оцінки ґрунтового покриву земель для вирощування технічних культур ТзОВ «Жива Земля Потутори» № поля Показники Потужність гуму- сового шару, см Реакція ґрунтово- го розчину, рНсол. Матеріал і методи досліджень Таб Таблиця 7 Дані агроекологічної оцінки ґрунтового покриву земель для вирощування кормових культур ТзОВ «Жива Земля Потутори» № поля Показники Потужність гумусового шару, см Реакція ґрунто- вого розчину, рНсол. Вміст в орному шарі гумусу, % Вміст азоту, що легко гідролізу- ється, мг/кг Вміст рухомого фосфору, мг/кг Вміст обмінно- го калію, мг/кг Сума активних температур вище 10 °С Гідротермічний коефіцієнт Рівень ґрунто- вих вод (РГВ), м Вміст рухомих форм важких металів (мг/кг): кадмію свинцю ртуть Рілля 1 Д О Д Д Д О О О О О Д О 2 Д О Д Д Д Д О О О О Д О 3 Д О Д Д О О О О О О Д О 4 Д О Н Д Д О О О О О Д О 5 Д О Д Д Д О О О О О Д О 6 Д О Д Д Д О О О О О Д О 7 Д О Д Д Н О О О О О Д О 9 Д О Д Д Н О О О О О Д О 16 Д О Д Н Н Д О О О О Д О Культурне пасовище 12 Д О Д Д Д Д О О О О Д О 13 Д О Д Д О Д О О О О Д О * О – оптимальні умови; Д – допустимі умови; Н – недопустимі умови (згідно класифікації В.В. Медведєва). Таблиця 7 Дані агроекологічної оцінки ґрунтового покриву земель для вирощування кормових культур ТзОВ «Жива Земля Потутори» № поля Показники Потужність гумусового шару, см Реакція ґрунто- вого розчину, рНсол. Матеріал і методи досліджень Вміст в орному шарі гумусу, % Вміст азоту, що легко гідролізу- ється, мг/кг Вміст рухомого фосфору, мг/кг Вміст обмінного калію, мг/кг Сума активних температур вище 10 °С Гідротермічний коефіцієнт Рівень ґрунто- вих вод (РГВ), м Вміст рухомих форм важких металів (мг/кг): кадмію свинцю ртуть Рілля 1 Д О Д Н О О О О О О Д О 2 Д О Д Н Д О О О О О О О 3 Д О О Н О О О О О О Д О 4 Д О Д Н О О О О О О Д О * О – оптимальні умови; Д – допустимі умови; Н – недопустимі умови (згідно класифікації В.В. Медведєва). Таблиця 7 Дані агроекологічної оцінки ґрунтового покриву земель для вирощування кормових культур ТзОВ «Жива Земля Потутори» № поля Показники Потужність гумусового шару, см Реакція ґрунто- вого розчину, рНсол. Вміст в орному шарі гумусу, % Вміст азоту, що легко гідролізу- ється, мг/кг Вміст рухомого фосфору, мг/кг Вміст обмінно- го калію, мг/кг Сума активних температур вище 10 °С Гідротермічний коефіцієнт Рівень ґрунто- вих вод (РГВ), м Вміст рухомих форм важких металів (мг/кг): кадмію свинцю ртуть Рілля 1 Д О Д Д Д О О О О О Д О 2 Д О Д Д Д Д О О О О Д О Таблиця 5 Таблиця 5 Дані агроекологічної оцінки ґрунтового покриву земель для вирощування технічних культур ТзОВ «Жива Земля Потутори» № поля Показники Потужність гуму- сового шару, см Реакція ґрунтово- го розчину, рНсол. Матеріал і методи досліджень Вміст в орному шарі гумусу, % Вміст азоту, що легко гідролізу- ється, мг/кг Вміст рухомого фосфору, мг/кг Вміст обмінно- го калію, мг/кг Сума активних температур вище 10 °С Гідротермічний коефіцієнт Рівень ґрунто- вих вод (РГВ), м Вміст рухомих форм важких металів (мг/кг): кадмію свинцю ртуть Рілля 1 Д О Д Д Д О О О О О Д О 2 Д О Д Д Д Д О О О О Д О 3 Д О Д Д О О О О О О Д О 4 Д О Н Д Д О О О О О Д О 5 Д О Д Д Д О О О О О Д О 6 Д О Д Д Д О О О О О Д О 7 Д О Д Д Н О О О О О Д О 9 Д О Д Д Н О О О О О Д О 16 Д О Д Н Н Д О О О О Д О Культурне пасовище 12 Д О Д Д Д Д О О О О Д О 13 Д О Д Д О Д О О О О Д О * О – оптимальні умови; Д – допустимі умови; Н – недопустимі умови (згідно класифікації В.В. Медведєва). Таблиця 7 Дані агроекологічної оцінки ґрунтового покриву земель для вирощування кормових культур ТзОВ «Жива Земля Потутори» № поля Показники Потужність гумусового шару, см Реакція ґрунто- вого розчину, рНсол. Матеріал і методи досліджень За реакцією ґрунтового середовища та за вмістом гумусу ґрунти господарств характеризуються опти- мальними умовами з метою вирощування як кормо- вих і технічних культур, так і зернових. Дана ситуа- ція обумовлена тим, що загалом ґрунти мають нейт- ральну реакцію, а також досліджувані поля характе- ризуються середньою забезпеченістю ґрунтів за вміс- том гумусу (знаходиться в межах 2,0–3,5% на всіх ділянках), за винятком (поле №4 – ТзОВ «Жива Зем- ля Потутори», характеризується недопустимими умо- вами), дана ситуація обумовлює задовільні умови для формування високоякісних врожаїв сільськогоспо- дарських культур. мі умови для вирощування кормових, технічних та зернових культур, аналогічна ситуація і в ТзОВ «Жи- ва Земля Потутори» – вміст обмінного калію колива- ється від 70,0 до 165 мг/кг ґрунту. На якість ґрунтів та агроекологічні умови вирощу- вання сільськогосподарських культур значно вплива- ють метеорологічні умови, зокрема сума активних температур вища за 10 °С та гідротермічний коефіці- єнт Селянінова (ГТК) (Panas, 2008). Різні культури для своєї життєдіяльності в період від проростання насіння до достигання потребують неоднакової кіль- кості тепла. За вимогливістю до тепла культури умо- вно поділяють на холодостійкі (жито, пшениця, яч- мінь, овес, горох та ін.), середньо холодостійкі (буря- ки, соняшник, боби, люпин, льон, та ін.), теплолюбні (кукурудза, просо, сорго, квасоля, рис, соя, бавовник та ін.). Згідно із нормативами агроекологічної оцінки, оптимальні умови за сумою активних температур (2530 °С) спостерігаються майже на всіх дослідних ділянках, оскільки мають сума температур становить вище 10 °С – 2530'. Аналогічна ситуація склалася в господарстві на всіх полях відносно до гідротерміч- ного коефіцієнту допустимі умови (ГТК–1,4). А зага- лом метеорологічні показники ґрунтів, відповідно до нормативів агроекологічних умов вирощування, мо- жуть забезпечити формування біологічно повноцінної продукції та сировини. р у ур Виходячи з таблиць 3–8 можна відмітити, що ґру- нти на досліджуваних ділянках за вмістом азоту, що легко гідролізується, характеризуються недопусти- мим умовами для вирощування зернових і технічних культур. Дана ситуація обумовлена тим, що на даних ділянках (поля № 1–7, 9, 16, 12–13 ТзОВ «Жива Зем- ля Потутори») вміст азоту, що легко гідролізується, перебуває в ґрунтах від 85,0 до 144 мг/кг та (поля № 1–4 ТОВ «Крона») – від 108 до 125мг/кг ґрунтуза Корнфілдом, а для оптимальних умов при вирощу- ванні зернових та технічних культур необхідно, щоб ґрунти були забезпечені вмістом азоту більше ніж 200 мг/кг ґрунту. Пороте даний вміст цього показни- ка в ґрунтах є допустимим значенням для вирощу- вання кормових культур на підприємстві ТзОВ «Жи- ва Земля Потутори», як це показано в таблиці 7. Матеріал і методи досліджень Вміст в орному шарі гумусу, % Вміст азоту, що легко гідролізу- ється, мг/кг Вміст рухомого фосфору, мг/кг Вміст обмінно- го калію, мг/кг Сума активних температур вище 10 °С Гідротермічний коефіцієнт Рівень ґрунто- вих вод (РГВ), м Вміст рухомих форм важких металів (мг/кг): кадмію свинцю ртуть Рілля 1 Д О Д Д Д О О О О О Д О 2 Д О Д Д Д Д О О О О Д О 3 Д О Д Д О О О О О О Д О 4 Д О Н Д Д О О О О О Д О 5 Д О Д Д Д О О О О О Д О 6 Д О Д Д Д О О О О О Д О 7 Д О Д Д Н О О О О О Д О 9 Д О Д Д Н О О О О О Д О 16 Д О Д Н Н Д О О О О Д О Культурне пасовище 12 Д О Д Д Д Д О О О О Д О 13 Д О Д Д О Д О О О О Д О * О – оптимальні умови; Д – допустимі умови; Н – недопустимі умови (згідно класифікації В.В. Медведєва). абл ані агроекологічної оцінки ґрунтового покриву земель для вирощування кормових культур ТзОВ «Жива Земля Потутори» Scientific Messenger LNUVMBT named after S.Z. Gzhytskyj, 2017, vol. 19, no 74 200 200 Науковий вісник ЛНУВМБТ імені С.З. Ґжицького, 2017, т 19, № 74 Таблиця 8 Дані агроекологічної оцінки ґрунтового покриву земель для вирощування кормових культур ТОВ «Крона» № поля Показники Потужність гумусового шару, см Реакція ґрунто- вого розчину, рНсол. Вміст в орному шарі гумусу, % Вміст азоту, що легко гідролізу- ється, мг/кг Вміст рухомого фосфору, мг/кг Вміст обмінного калію, мг/кг Сума активних температур вище 10 °С Гідротермічний коефіцієнт Рівень ґрунто- вих вод (РГВ), м Вміст рухомих форм важких металів (мг/кг): кадмію свинцю ртуть Рілля 1 Д О Д Н О Д О О О О Д О 2 Д О Д Н Д О О О О О Д О 3 Д О О Н О О О О О О Д О 4 Д О Д Н О О О О О О Д О * О – оптимальні умови; Д – допустимі умови; Н – недопустимі умови (згідно класифікації В.В. Медведєва). Д тимі умови; Н – недопустимі умови (згідно класифікації В.В. Медведєва). Матеріал і методи досліджень Одним із основних факторів, які впливають на якість продукції є вміст в грунті рухомих форм важ- ких металів. Підвищений вміст важких металів у ґру- нті може бути наслідком застосування в сільському господарстві меліорантів, добрив та пестицидів, а також використання для зрошення забруднених побу- тових і промислових стічних вод тощо. За даними В.І. Кисіля гранично допустима концентрація (далі ГДК) для кадмію – 0,7 мг/кг ґрунту, для Свинцю – 2,0 мг/кг ґрунту для Ртуті – 0 мг/кг (Lisovyi, 1991). За вмістом рухомих форм фосфору ґрунти дослі- джуваних ділянок характеризуються підвищеним та високим забезпеченням, що обумовлює оптимальні та допустимі умови для вирощування як зернових і тех- нічних культур, так і для кормових. Вміст даного показника в ґрунтах ТОВ «Крона» коливається в ме- жах від 80,0 до 185 мг/кг ґрунту за Мачигіним, що створює задовільні умови для формування високоякі- сних врожаїв, а в ТзОВ «Жива Земля Потутори»вміст даного показника в ґрунтах з оптимальними та допу- стимими умови коливається в межах від 57,0 до 109 мг/кг ґрунту (поля № 7, 9, 16) характеризується недопустимими умовами для вирощування сільсько- господарських культур (Ridei et al., 2011). Scientific Messenger LNUVMBT named after S.Z. Gzhytskyj, 2017, vol. 19, no 74 201 Висновки Отже, результати досліджень підтверджують, що на сільськогосподарських підприємствах Тернопіль- ської області Бережанського району ТзОВ «Жива Земля Потутори» та ТОВ «Крона» переважають поля з оптимальними умовами для вирощування зернових, технічних та кормових культур, за таких умов мож- Вміств ґрунтах ТОВ «Крона» обмінного калію ко- ливається від 106,0 до 136 мг/кг ґрунт за Мачигіним, що, в свою чергу, обумовлює оптимальні та допусти- Scientific Messenger LNUVMBT named after S.Z. Gzhytskyj, 2017, vol. 19, no 74 201 201 Науковий вісник ЛНУВМБТ імені С.З. Ґжицького, 2017, т 19, № 74 lisostepu Ukrainy. TFDU «Derzhhruntokhorona» Ternopil (in Ukrainian). ливо отримати найбільші екологічно чисті врожаї. Щодо грунтового покриву, який характеризується допустимими (задовільними) умовами, на вище вка- заних господарствах є поля з загрозою зниження врожайності на 23–30%. Лімітуючим фактором, який може знизити формування врожайності до 50%, є низька забезпеченість поживними речовинами, а саме сполуками азоту, що легко гідролізується, дана ситу- ація склалась лише на окремих ділянках. Варто вста- новити найбільш оптимальні дози органічних та мі- неральних добрив, вести планомірну роботу щодо підвищення родючості грунту, адже добрива – основа живлення – елемент побудови урожаю. Patyka, V.P., Tarariko, O.H. (2002). Ahroekolohichnyi monitorynh ta pasportyzatsiia silskohospodarskykh uhid. K.: Fitosotsiotsentr (in Ukrainian). Medvedeva, V.V. (1997). Agroekologicheskaja ocenka zemel' Ukraini i razmeshheniesel'skozjajsivennih kul'tur. K.:Agrarna nauka (in Russian). Ridei, N.M., Strokal, V.P., Rybalko, Yu.V. (2011). Ekolohichna otsinka ahrobiotsenoziv: teoriia, metodyka, praktyka. Kherson: Vydavnytstvo Oldi – plius (in Ukrainian). Panas, R.M. (2008). Ratsionalne vykorystannia ta okhorona zemel: navch. posibnyk. Lviv: Novyi Svit (in Ukrainian). Scientific Messenger LNUVMBT named after S.Z. Gzhytskyj, 2017, vol. 19, no 74 202 Бібліографічні посилання Lisovyi, M.V. (1991). Pidvyshchennia efektyvnosti mineralnykh dobryv. K.: Urozhai (in Ukrainian). Стаття надійшла до редакції 22.02.2017 Broshchak, I.S. (2013). Rekomendatsii po udobrenniu silskohospodarskykh kultur v umovakh zakhidnoho Scientific Messenger LNUVMBT named after S.Z. Gzhytskyj, 2017, vol. 19, no 74 202
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Oxygen-Conserving Implications of the Trigemino-Cardiac Reflex in the Brain: The Molecular Basis of Neuroprotection?
Molecular medicine
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© 2009 The Feinstein Institute for Medical Research, www.feinsteininstitute.org Online address: http://www.molmed.org doi: 10.2119/molmed.2009.00013 The trigemino-cardiac reflex (TCR) is defined as a sudden dysrhythmia with arterial hypotension accompanied by apnea or gastric hypermotility after stim- ulation of any of the sensory branches of the trigeminal nerve (1). The sensory nerve endings of the trigeminal nerve transmit neuronal signals via the Gasser- ian ganglion to the sensory nucleus of the trigeminal nerve (2). This initiates ad- justments in the systemic and cerebral circulation to adjust the cerebral blood flow in a manner that is not yet well un- derstood (3). Extensive investigations in animals have documented the involve- ment of supramedullary regions of the brain in cardiovascular regulation (4–6). It appears that the cerebrovascular re- sponse as part of the TCR is generated by the activation of the reticulospinal neurons of the rostral ventrolateral medulla (RVLM) to elevate cerebral blood flow (CBF) reflexively and most likely slow cerebral metabolism as part of an oxygen-conserving reflex. The exis- tence of such endogenous neuroprotec- cal adjustments are bradycardia and pe- ripheral vasoconstriction, but also the initiation of apnea. Cardiac output is re- distributed to favor blood flow to the heart and brain, while blood flow to most visceral organs, inactive muscle groups, and the skin are reduced. The TCR therefore causes redistribution in blood supply. Transcranial Doppler ul- trasonography (TCD) studies give a re- producible value of brain perfusion by continuous non-invasive real-time sam- pling (7). With TCD, it can be shown that the CBF rises in the middle cere- bral artery (MCA) in healthy subjects during facial cooling with normal venti- lation when resting in a supine position without any change in the systemic blood pressure (7). This may suggest a neuroprotective effect of the TCR and therefore some kind of an oxygen- conserving effect. Despite this prelimi- nary data it is yet unknown how ex- actly CBF and cerebral metabolism are affected by the TCR. tive strategies also may have an impor- tant physiological role namely by stabi- lizing the brain function and by the pre- vention of permanent cerebral ischemic damage. However, examinations of higher influences on basic cardiovascular control mechanisms in man are still sparse. higher influences on basic cardiovascular control mechanisms in man are still sparse. Diving reflex is an example of a pe- ripheral TCR. The main stimuli eliciting the diving reflex is the chilling of the face. Commentary Commentary Address correspondence and reprint requests to Bernhard Schaller, Rämelstrasse 12, CH- 4106 Therwil, Switzerland. E-mail: bernhard.schaller@yahoo.de. Submitted March 2, 2009; Accepted for publication March 3, 2009; Epub (www.molmed. org) ahead of print March 6, 2009. Bernhard J Schaller,1 Nora Sandu,2 Jan F Cornelius,1 Andreas Filis,3 and Miguel A Perez-Pinzon,4 for the Trigemino-Cardiac-Reflex-Examination-Group (T.C.R.E.G.) 1Department of Neurosurgery, University Hospitals of Paris, Paris, France, and 2Department of Neurosurgery, University Hospital Lausanne, Lausanne, Switzerland; 3Case Western Reserve University, Minimally Invasive Neurosurgery Lab, University Hospital, Cleveland, Ohio, United States of America; and 4Cerebral Vascular Disease Research Center, University of Miami Miller School of Medicine, Miami, Florida, United States of America Oxygen-Conserving Implications of the Trigemino-Cardiac Reflex in the Brain: The Molecular Basis of Neuroprotection? Bernhard J Schaller,1 Nora Sandu,2 Jan F Cornelius,1 Andreas Filis,3 and Miguel A Perez-Pinzon,4 for the Trigemino-Cardiac-Reflex-Examination-Group (T.C.R.E.G.) Bernhard J Schaller,1 Nora Sandu,2 Jan F Cornelius,1 Andreas Filis,3 and Miguel Trigemino-Cardiac-Reflex-Examination-Group (T.C.R.E.G.) REFERENCES and mediating the vasomotor compo- nent of cardiovascular reflexes (8). In fact, exposure of excised slices from the RVLM to either hypoxia or sodium cyanide (which inhibits mitochondrial respiration), results in neuronal excita- tion (9). Extensive studies have been car- ried out on the mechanisms by which these reflexes mediate vasomotor re- sponses in response to hypoxia. For ex- ample, two K+ ATP channel inhibitors in- jected into RVLM, tolbutamide and glibenclamide, elevated arterial pressure and rCBF, potentiating the hypoxic re- sponses (10). Finally, the RVLM neurons are the principal relay for the cerebro- vascular dilation mediated by the cere- bellar fastigial nucleus (FN) (8). In fact, direct electrical stimulation of the cere- bellar FN protected the CA1 region of the hippocampus and reduced infarct volume by 50% after global (11) and focal (12) cerebral ischemia, respectively. 1. Schaller B, Probst R, Strebel S, Gratzl O. (1999) Trigeminocardiac reflex during surgery in the cerebellopontine angle. J. Neurosurg. 90:215–20. 2. Schaller B. (2004) Trigeminocardiac reflex. A clin- ical phenomenon or a new physiological entity? J. Neurol. 251:658–65. 3. Schaller B, Cornelius JF, Sandu N, Ottaviani G, Perez-Pinzon M. (2009) Invited manuscript: oxygen-conserving reflexes of the brain: the cur- rent molecular knowledge. J. Cell. Mol. Med. 2009, Jan 16 [Epub ahead of print]. 4. Delgado JM. (1960) Circulatory effects of cortical stimulation. Physiol. Rev. Suppl 4:146–78. 5. Hoff EC, Kell JF Jr, Carroll MN Jr. (1963) Effects of cortical stimulation and lesions on cardiovas- cular function. Physiol. Rev. 43:68–114. 6. Hilton SM. (1975) Ways of viewing the central nervous control of the circulation—old and new. Brain Res. 87:213–9. 7. Lohmann H, Ringelstein EB, Knecht S. (2006) Functional transcranial Doppler sonography. Front Neurol. Neurosci. 21:251–60. 8. Reis DJ, et al. (1997) Central neurogenic neuro- protection: central neural systems that protect the brain from hypoxia and ischemia. Ann. N. Y. Acad. Sci. 835:168–86. 8. Reis DJ, et al. (1997) Central neurogenic neuro- protection: central neural systems that protect the brain from hypoxia and ischemia. Ann. N. Y. Acad. Sci. 835:168–86. 9. Sun MK, Jeske IT, Reis DJ. (1992) Cyanide excites medullary sympathoexcitatory neurons in rats. Am. J. Physiol. 262:R182–9. Interestingly, it seems that the same neuronal centers, the rostral neurons in the ventrolateral medulla, play a major role in protecting the brain of ischemic insult whether the underlying event is acute, chronic, or intermittent. REFERENCES In fact, in the case of TCR, the brain is protected instantly by a reflex-mediated response of the cardiovascular system. If hypox- emia is chronic or intermittent, brain protection results from long-term adap- tive changes on the cellular and molecu- lar level that occur in the same cell groups of import in the acute changes mediated by the TCR, suggesting an oxygen-conserving part of the TCR. The exact relationship between reflective, acute changes of physiological parame- ters and long-term changes on the mo- lecular level are unclear; more basic re- search has to be done to underline this hypothesis. 10. Golanov EV, Reis DJ. (1999) A role for KATP+- channels in mediating the elevations of cerebral blood flow and arterial pressure by hypoxic stimulation of oxygen-sensitive neurons of ros- tral ventrolateral medulla. Brain Res. 827:210–4. 10. Golanov EV, Reis DJ. (1999) A role for KATP+- channels in mediating the elevations of cerebral blood flow and arterial pressure by hypoxic stimulation of oxygen-sensitive neurons of ros- tral ventrolateral medulla. Brain Res. 827:210–4. 11. Golanov EV, Liu F, Reis DJ. (1998) Stimulation of cerebellum protects hippocampal neurons from global ischemia. Neuroreport. 9:819–24. 12. Reis DJ, Kobylarz K, Yamamoto S, Golanov EV. (1998) Brief electrical stimulation of cerebellar fastigial nucleus conditions long-lasting salvage from focal cerebral ischemia: Conditioned central neurogenic neuroprotection. Brain Res. 780:161–5. C O M M E N T A R Y C O M M E N T A R Y © 2009 The Feinstein Institute for Medical Research, www.feinsteininstitute.org Online address: http://www.molmed.org doi: 10.2119/molmed.2009.00013 The most pronounced physiologi- The oxygen-conserving reflexes are sympathetically mediated vasomotor re- sponses of a small population of neu- rons that reside in the subnucleus of the C1 area of the RVLM (11,12). These neu- rons mediate sympathetic and cerebro- vascular responses to hypoxia and play a critical role in modulating circulatory control, maintaining arterial pressure, Address correspondence and reprint requests to Bernhard Schaller, Rämelstrasse 12, CH- 4106 Therwil, Switzerland. E-mail: bernhard.schaller@yahoo.de. Submitted March 2, 2009; Accepted for publication March 3, 2009; Epub (www.molmed. org) ahead of print March 6, 2009. M O L M E D 1 5 ( 5 - 6 ) 1 2 5 - 1 2 6 , M A Y- J U N E 2 0 0 9 | S C H A L L E R E T A L . | 1 2 5 12. Reis DJ, Kobylarz K, Yamamoto S, Golanov EV. (1998) Brief electrical stimulation of cerebellar fastigial nucleus conditions long-lasting salvage from focal cerebral ischemia: Conditioned central neurogenic neuroprotection. Brain Res. 780:161–5. 11. Golanov EV, Liu F, Reis DJ. (1998) Stimulation of cerebellum protects hippocampal neurons from global ischemia. Neuroreport. 9:819–24. DISCLOSURE We declare that the authors have no competing interests as defined by Molec- ular Medicine, or other interests that might be perceived to influence the re- sults and discussion reported in this paper. 1 2 6 | S C H A L L E R E T A L . | M O L M E D 1 5 ( 5 - 6 ) 1 2 5 - 1 2 6 , M A Y- J U N E 2 0 0 9
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Transient rRNA synthesis inhibition with CX-5461 is sufficient to elicit growth arrest and cell death in acute lymphoblastic leukemia cells
Oncotarget
2,015
cc-by
8,485
Sandeep S. Negi1, Patrick Brown1 Sandeep S. Negi1, Patrick Brown1 1Department of Oncology and Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA Correspondence to: Patrick Brown, e-mail: pbrown2@jhmi.edu Keywords: CX-5461, rRNA synthesis, UCN-01, acute lymphoblastic leukemia, MAP kinase Received: May 31, 2015 Accepted: September 30, 2015 Published: October 12, 2015 1Department of Oncology and Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA Correspondence to: Patrick Brown e-mail: pbrown2@jhmi edu 1Department of Oncology and Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA Correspondence to: Patrick Brown, e-mail: pbrown2@jhmi.edu Keywords: CX-5461, rRNA synthesis, UCN-01, acute lymphoblastic leukemia, MAP kinase Keywords: CX-5461, rRNA synthesis, UCN-01, acute lymphoblastic leukemia, MAP kinase Received: May 31, 2015 Accepted: September 30, 2015 Published: October 12 Published: October 12, 2015 www.impactjournals.com/oncotarget/ www.impactjournals.com/oncotarget/ ABSTRACT Enhanced rRNA synthesis is a downstream effect of many of the signaling pathways that are aberrantly activated in cancer, such as the PI3K/mTOR and MAP kinase pathways. Recently, two new rRNA synthesis inhibitors have demonstrated therapeutic effects on cancer cells while sparing normal cells. One of them, CX-5461, is currently in phase 1 clinical trials for hematological malignancies. Here, we investigate the effectiveness of transient treatment with this drug on acute lymphoblastic leukemia cells. Our results show that short exposure to CX-5461 followed by drug washout is sufficient to induce persistent G2 cell-cycle arrest and irreversible commitment to cell death, in spite of rRNA synthesis returning to normal within 24 hours of drug washout. The magnitude of cell death after transient exposure is similar to continuous exposure, but the time to cell death is relatively delayed with transient exposure. In this report, we also investigate rational drug combinations that can potentiate the effect of continuous CX-5461 treatment. We show that the checkpoint abrogator UCN-01 can relieve CX-5461-induced G2 arrest and potentiate the cytotoxic effects of CX-5461. Finally, we show that ERK1/2 is activated upon CX-5461 treatment, and that pharmacological inhibition of MEK1/2 leads to enhanced cell death in combination with CX-5461. In summary, our results provide evidence for the effectiveness of CX-5461 pulse treatment, which may minimize drug related toxicity, and evidence for enhanced effectiveness of CX-5461 in combination with other targeted agents. Oncotarget, Vol. 6, No. 33 Oncotarget, Vol. 6, No. 33 INTRODUCTION To assess the extent to which reduced proliferation was due to induction of cell death (as opposed to growth arrest only), we measured cell death at day 3 after washout using FACS after staining with propidium iodide (PI). All cell lines showed significant reduction in proportion of live cells (i.e., PI negative) in washout cells compared to DMSO treated controls after 3 days (Figure 1B). To investigate if a shorter incubation with CX-5461 would still result in cytotoxicity, we exposed the cells to CX-5461 for 3 hours and 5 hours. We measured cell viability using trypan blue 4 days after washout. All cell lines showed a reduction in viability in drug washout cells (Figure 1C). We then investigated if transient exposure would lead to cytotoxicity in primary patient samples. We have previously shown that normal bone marrow cells show minimal cell death when treated with 1 μM CX-5461 for two days [19]. For transient exposure, we treated patient samples (n = 3) for 5 hours with 1 μM CX-5461, washed them twice and resuspended in drug free media. Cell death was measured with PI staining. All three samples showed reduced viability in drug washout, and to a similar extent as with continuous treatment compared to DMSO treated controls (Figure 1D). Taken together, these results show that short exposure to CX-5461 is sufficient to induce cell death in acute leukemia cells. p CX-5461 is the first potent and selective inhibitor of RNA pol I transcription [16]. Recently, the rRNA synthesis inhibitors, CX-5461 and BMH-21, have shown therapeutic potential in different cancer models [10, 13, 17]. These drugs have distinct mechanisms of action of inhibiting rRNA synthesis. BMH-21 was initially discovered as an activator of p53, and was later found to induce nucleolar stress by inhibiting RNA pol I binding to the rDNA promoter and decreased rRNA synthesis [13, 18]. In contrast, CX-5461 inhibits the interaction between SL1 and rDNA thereby preventing the formation of pre- initiation complex. Bywater et al. [10] showed therapeutic potential of CX-5461 treatment in mouse model of melanoma and MLL-AF9 acute myeloid leukemia. Their work showed that nucleolar stress caused by CX-5461 selectively led to p53 activation and subsequent apoptosis in cancer cells. Recently, we have shown that CX-5461 arrests acute lymphoblastic leukemia (ALL) cells in G2 phase and induces apoptosis in p53 independent manner [19]. INTRODUCTION of mature ribosome from the nucleus to the cytoplasm [4]. Nucleolar stress caused by drugs or environmental factors can lead to unraveling of the nucleolus and the release of nucleolar proteins into the nucleoplasm. Rubbi et al. [5] first proposed that impairment of nucleolar function in response to cellular stress leads to p53 activation, which in turn leads to cell-cycle arrest or apoptosis. The primary role of the nucleolus is to synthesize ribosomes. However, identification of the nucleolar proteome showed that a majority of nucleolar proteins have functions unrelated to ribosome biogenesis, such as cell-cycle regulation and stress response, [1, 2] and subsequent studies have discovered novel functions for the nucleolus both in normal and disease states [3]. The nucleolus is a dynamic structure which is formed by the act of making ribosome. Nucleolar stress can be caused by inhibition of any of the many steps involved in ribosome biogenesis including pre-ribosomal RNA (rRNA) synthesis, rRNA processing, and assembly of ribosomal proteins on nascent rRNA transcripts and export Ribosome biogenesis is a highly coordinated process that is regulated by tumor suppressor proteins and oncogenes [6]. Morphological and structural changes in the nucleolus were one of the earliest reported markers in cancer. RNA polymerase I (RNA pol I) is responsible for the synthesis of pre-rRNA. Elevated RNA pol I activity due to increased growth and protein synthesis demand is a hallmark of cancer [6, 7]. In fact, some of the major www.impactjournals.com/oncotarget Oncotarget 34846 signaling pathways deregulated in cancers directly affect ribosome biogenesis. Among them, c-Myc and PI3K-AKT-mTOR signaling directly regulate multiple steps in ribosome biogenesis [8, 9]. As ribosome biogenesis is an essential cellular process for normal cells, its therapeutic targeting in cancer seems unlikely. However, recently, a class of drugs targeting rDNA transcription has shown promise as novel cancer treatment in pre-clinical models [10, 11, 12, 13, 14, 15]. These studies have shown that therapeutically inhibiting rDNA transcription with these drugs selectively kills cancer cells and spares normal cells. irrevocably induce cell death in ALL cells. Cells were treated with 250 nM CX-5461 or DMSO for 24 hours, washed twice in the culture medium and suspended in drug free medium. We measured cell proliferation using the colorimetric MTS assay at day 1 and 3 after resuspension. All cell lines showed a time dependent reduction in cell proliferation in washout cells relative to control treated cells (Figure 1A). INTRODUCTION In recent years, potent but transient inhibition of BCR-ABL kinase in CML, and PI3K in breast cancer models has been shown to be an effective therapeutic strategy [20, 21, 22]. Here, we investigated the cellular response to transient inhibition of rRNA synthesis with CX-5461 treatment. We found that short exposure to CX-5461 produces similar effects as seen with continuous treatment. Despite reactivation of rRNA synthesis activity within 24 h of drug washout, transient and potent inhibition of rRNA synthesis with CX-5461 was sufficient to commit ALL cells to irreversible cell death. Apart from acute treatment strategy, we also investigated rational drug combinations that can enhance the cytotoxicity of continuous CX-5461 treatment. In this report we analyzed the effect of inhibiting cellular pathways activated by CX-5461 treatment. We showed that checkpoint kinase inhibitor UCN-01 and MAPK pathway inhibitors enhance CX-5461 mediated cytotoxicity. rRNA synthesis recovers in drug washout cells To further investigate changes induced by transient treatment, we treated SEM and NALM-6 cells with CX-5461 for 3 hours, washed twice and resuspended them in drug free media. We then investigated the effects of drug washout on cell-cycle distribution, rRNA synthesis and cell viability. Cell-cycle results show that 24 hours after washout (CX w/o), cells show an increase in the G2/M population compared to control treated cells, although the magnitude of the increase is less than that seen with continuously treated cells (CX-5461) (Figure 2A and Supplementary Figure 1A). We used 45S pre-rRNA transcript levels, which are known to have a very short half-life (several minutes), as a measure of the rate of rRNA synthesis. We have shown previously that 250 and 500 nM CX- 5461 reduces pre-rRNA synthesis by more than 50% by 3 hours in SEM and NALM-6 cells respectively [19]. We first measured 45S pre-rRNA levels at 3 hours after CX-5461 treatment to confirm inhibition of RNA pol I transcription (Supplementary Figure 1B). The cells were then washed and suspended in drug free media for 24 hours to check if pre-rRNA synthesis recovered www.impactjournals.com/oncotarget Transient exposure to CX-5461 is cytotoxic We first established a washout procedure to evaluate whether transient exposure to CX-5461 is sufficient to www.impactjournals.com/oncotarget Oncotarget 34847 i Figure 1: Transient inhibition of rRNA synthesis affects cell proliferation. A. Four ALL cell lines were treated with 250 nM CX-5461 or DMSO for 24 h. Cells were washed and equal number of CX-5461 or DMSO treated cells were seeded in drug free medium in 96 well plates and cell proliferation was measured at Day 1 and 3. Data is normalized to the growth in DMSO treated samples. All four ALL cell lines show time dependent decrease in proliferation relative to their DMSO treated controls. Data represents mean +/− S.D. of three independent experiments. B. Cells were treated as in (a) and cell death was measured three days after washout by propidium iodide staining (PI). Data represent mean +/− S.D. of three independent experiments. C. Cells were treated for 3 hours or 5 hours with CX-5461 (500 nM for NALM-6 and 250 nM for SEM, KOPN-8 and RS4;11) or DMSO followed by washing. Cells were incubated in drug free media and cell viability was measured using trypan blue after three days. Drug washout cells show reduced viability compared to control treated cells. Data represent mean +/− S.D. of three independent experiments. D. Three ALL patient samples were treated with 1 μM CX-5461 or DMSO for 5 hours. After 5 hours the CX-5461 treated cells were washed, incubated with either DMSO (w/o) or 1 μM CX-5461 (CX); the DMSO treated cells were washed and incubated in DMSO (DMSO). After 2 days, cell death was measured using PI staining. All three patient samples, continuously or transiently treated with CX-5461, showed reduced viability compared to DMSO treated control. Viable proportion is plotted from duplicate experiments. Figure 1: Transient inhibition of rRNA synthesis affects cell proliferation. A. Four ALL cell lines were treated with 250 nM CX-5461 or DMSO for 24 h. Cells were washed and equal number of CX-5461 or DMSO treated cells were seeded in drug free medium in 96 well plates and cell proliferation was measured at Day 1 and 3. Data is normalized to the growth in DMSO treated samples. All four ALL cell lines show time dependent decrease in proliferation relative to their DMSO treated controls. Data represents mean +/− S.D. of three independent experiments. B. Transient exposure to CX-5461 is cytotoxic Cells were treated as in (a) and cell death was measured three days after washout by propidium iodide staining (PI). Data represent mean +/− S.D. of three independent experiments. C. Cells were treated for 3 hours or 5 hours with CX-5461 (500 nM for NALM-6 and 250 nM for SEM, KOPN-8 and RS4;11) or DMSO followed by washing. Cells were incubated in drug free media and cell viability was measured using trypan blue after three days. Drug washout cells show reduced viability compared to control treated cells. Data represent mean +/− S.D. of three independent experiments. D. Three ALL patient samples were treated with 1 μM CX-5461 or DMSO for 5 hours. After 5 hours the CX-5461 treated cells were washed, incubated with either DMSO (w/o) or 1 μM CX-5461 (CX); the DMSO treated cells were washed and incubated in DMSO (DMSO). After 2 days, cell death was measured using PI staining. All three patient samples, continuously or transiently treated with CX-5461, showed reduced viability compared to DMSO treated control. Viable proportion is plotted from duplicate experiments. from the cells. Newly synthesized EU labeled transcripts were isolated as described in materials and methods. Our results show no difference in the levels of newly transcribed 45S pre-rRNA in DMSO and CX-5461 washout cells at 0 hour (Figure 2C). Moreover, 3 hours after chase, levels of the EU labeled 45S pre- rRNA decreases substantially. The decrease was similar in both DMSO and CX-5461 washout cells suggesting efficient processing of 45S pre-rRNA transcript under both conditions. following washout. Both cell lines showed significant pre-rRNA synthesis inhibition at 3 hours (CX 3 h) and almost complete recovery at 24 hours after washout (CX w/o) (Figure 2B and Supplementary Figure 1B). Ribosome biogenesis is a highly coordinated process and inhibition of rRNA synthesis can lead to pre- rRNA processing defects. In order to make sure that the increase in the levels of 45S pre-rRNA in drug washout cells is not due to pre-rRNA processing defects, we labeled SEM cells with ethynyl uridine (EU) for 30 min followed by chase in EU free media. RNA was isolated at 0 and 3 hours after EU washout following washout. Both cell lines showed significant pre-rRNA synthesis inhibition at 3 hours (CX 3 h) and almost complete recovery at 24 hours after washout (CX w/o) (Figure 2B and Supplementary Figure 1B). Transient exposure to CX-5461 is cytotoxic Ribosome biogenesis is a highly coordinated process and inhibition of rRNA synthesis can lead to pre- rRNA processing defects. In order to make sure that the increase in the levels of 45S pre-rRNA in drug washout cells is not due to pre-rRNA processing defects, we labeled SEM cells with ethynyl uridine (EU) for 30 min followed by chase in EU free media. RNA was isolated at 0 and 3 hours after EU washout Next, we measured cell viability of these cells after washout at day 1 and 3 using trypan blue. The results show www.impactjournals.com/oncotarget Oncotarget 34848 Figure 2: Transient potent rRNA synthesis inhibition with CX-5461 is sufficient to commit ALL cells to cell death despite reactivation of rRNA synthesis. A. SEM and NALM-6 cells were treated with 250 or 500 nM CX-5461, respectively. An aliquot was harvested after 3 hours, washed twice and cells were suspended in drug free media. Cell-cycle distribution was analyzed after 24 hours by flow cytometry of PI stained cells. Cells show aberrant cell-cycle distribution in drug washout cells compared to DMSO treated control cells. Representative flow cytometry data is shown from one of the three experiments. B. 45S pre-rRNA transcript levels were measured using quantitative PCR and normalized to the expression of GAPDH and Actin. DMSO and CX-5461 washout cells (CX w/o) show no difference in pre-rRNA synthesis at 24 hours. Experiments were repeated three times and data represents mean +/− S.D. C. Schematic of EU labeling of drug washout SEM cells. Newly synthesized EU labeled 45S pre-rRNA transcript levels were measured at 0 and 3 hours after EU removal. D. Cells were treated as in (a) and cell viability was measured using trypan blue staining. Drug washout cells show reduced viability compared to DMSO treated cells. Experiments are repeated three times. Data represents mean +/− S.D. E. SEM and NALM-6 cells were treated as before. NALM-6 cells show an increase in p53 and phospho-p53 levels at 3 hours after CX-5461 treatment. Elevated p53 levels in NALM-6 cells were substantially reduced 24 hours after drug washout. Figure 2: Transient potent rRNA synthesis inhibition with CX-5461 is sufficient to commit ALL cells to cell death despite reactivation of rRNA synthesis. A. SEM and NALM-6 cells were treated with 250 or 500 nM CX-5461, respectively. An aliquot was harvested after 3 hours, washed twice and cells were suspended in drug free media. Transient exposure to CX-5461 is cytotoxic Cell-cycle distribution was analyzed after 24 hours by flow cytometry of PI stained cells. Cells show aberrant cell-cycle distribution in drug washout cells compared to DMSO treated control cells. Representative flow cytometry data is shown from one of the three experiments. B. 45S pre-rRNA transcript levels were measured using quantitative PCR and normalized to the expression of GAPDH and Actin. DMSO and CX-5461 washout cells (CX w/o) show no difference in pre-rRNA synthesis at 24 hours. Experiments were repeated three times and data represents mean +/− S.D. C. Schematic of EU labeling of drug washout SEM cells. Newly synthesized EU labeled 45S pre-rRNA transcript levels were measured at 0 and 3 hours after EU removal. D. Cells were treated as in (a) and cell viability was measured using trypan blue staining. Drug washout cells show reduced viability compared to DMSO treated cells. Experiments are repeated three times. Data represents mean +/− S.D. E. SEM and NALM-6 cells were treated as before. NALM-6 cells show an increase in p53 and phospho-p53 levels at 3 hours after CX-5461 treatment. Elevated p53 levels in NALM-6 cells were substantially reduced 24 hours after drug washout. CX-5461 activates MAPK signaling pathway As ribosome biogenesis is a highly regulated process, we investigated other signaling pathways activated by rRNA synthesis inhibition. We incubated a human phospho-kinase protein array with equal amounts of cell lysates from SEM cells treated with CX-5461 or DMSO for one day. CX-5461 treated cells showed an increase in pERK1/2 (Thr202/Tyr204), pCHK2 (T68) and HSP60 levels (Figure 5A). We further confirmed the activation of ERK1/2 with western blot from CX-5461 treated SEM, NALM-6 and KOPN-8 cells (Figure 5B). We investigated if pharmacological inhibition of the MEK/ERK signaling pathway would abrogate CX-5461 induced ERK1/2 activation and potentiate the effect of rRNA synthesis inhibition. We treated SEM cells with MEK1/2 inhibitor, U-0126, in combination with CX-5461 for one day. Western blot results show that  U-0126 reduced the levels of pERK induced by CX-5461 treatment (Figure 6A). More-over, cell viability was substantially reduced in cells treated with a combination of U-0126 and CX-5461 compared to CX-5461 or U-0126 alone (Figure 6B). To further confirm that treatment with MEK/ERK inhibitor can enhance CX-5461 cytotoxic effect, we treated ALL cell lines with another MEK1/2 inhibitor, trametinib. Cells were treated with 150 nM trametinib in combination with CX-5461 for 2 days and cell viability was measured by trypan blue staining. As seen with U-0126, trametinib treated cells show significant increase in cell death in www.impactjournals.com/oncotarget www.impactjournals.com/oncotarget Oncotarget 34849 lead to increased cell death. Checkpoint kinases 1 and 2 (CHK1/2) are downstream effectors of ATM/ATR pathway and are activated upon CX-5461 treatment [19]. UCN-01, a staurosporine analogue, is a potent inhibitor of CHK1/2 and sensitizes tumor cells to genotoxic agents by abrogating G2 arrest induced by these drugs [23, 24]. Although UCN-01 is an inhibitor of the protein kinase C (PKC) family of enzymes, G2 checkpoint abrogation by inhibiting checkpoint kinases play a major role in its  anticancer activity [25, 26, 27]. To determine if UCN-01 can abrogate CX-5461 induced G2 arrest, we pre-treated cells with UCN-01 followed by continuous CX-5461 treatment for 24 hours. Cell- cycle analysis shows that CX-5461 treatment induced G2 arrest in SEM, KOPN-8 and NALM-6 cells. This arrest was completely abolished by UCN-01 pre- treatment (Figure 4A). We then investigated if UCN- 01 treatment will enhance the cytotoxicity of CX-5461 as seen previously in combination with ATR inhibitor. We pre-treated cells with UCN-01 for 1 hour followed by CX-5461 and measured cell viability using trypan blue. Combination treatment with CX-5461 and UCN- 01 significantly reduced cell viability in all three cell lines compared to CX-5461 or UCN-01 treatment alone (Figure 4B). that transient inhibition of rRNA synthesis substantially decreased cell viability (Figure 2D). These results confirm that despite reactivation of rRNA synthesis activity within 24 hours of drug washout, short-term rRNA synthesis inhibition with CX-5461 was sufficient to inhibit cell cycling and viability. We have previously shown that p53 levels were increased upon 24 hours CX-5461 treatment in p53 wild-type cell lines, although cell-cycle arrest and apoptotic effects were p53-independent [19]. To investigate if p53 levels remains elevated in CX-5461 washout cells, we measured p53 and phospho-p53 levels in drug treated and drug washout cells (Figure 2E). As shown previously [19], there was no increase in p53 levels in SEM cells (p53 mutant cell line). In NALM-6 cells (p53 wild-type cell line), there was an increase in p53 and phospho-p53 levels initially at 3 hours after drug treatment but drug washout resulted in a decrease in p53 levels when measured after 24 hours. Washout effectively removes residual drug from the culture medium We considered the possibility that the cytotoxic effect seen after drug washout is due to incomplete removal of the drug. To test for any residual drug, the cell culture supernatant (S) from drug treated cells after two washes was transferred to previously untreated cells (naïve) (Figure 3A). These cells were allowed to grow for three days and cell viability was measured by trypan blue staining. Our results show no reduction in viability of cells incubated in media from drug wash out cells similar to untreated control cells (Figure 3B). These results show effective removal of the drug from the culture media following two washes. We further tested the effect of washout itself on cell viability. SEM cells were treated with CX-5461 or DMSO for 3 hours followed by two washes in drug free media. As shown in Figure 3C, washout has no effect on cell viability as DMSO washout cell show similar viability as control unwashed cells. Also, these results suggest a lag in cell death in drug washout cells compared to continuously treated cells (Figure 3C). UCN-01 treatment relieves cell-cycle arrest and shows enhanced cell killing in combination with CX-5461 SEM cells were continuously incubated in DMSO or CX-5461 and a portion was harvested after 3 hours followed by washing in drug free media as before. Cell viability was measured using trypan blue staining at day 0, 1, 2 and 3 after washout. Results are plotted as mean +/− S.D. Figure 3: Washout procedure completely removes drug from the media. A. Schematic of drug treatment experiment in (b). SEM and NALM-6 cells were continuously treated with DMSO or with 250 or 500 nM CX-5461 (CX) respectively. A portion of CX-5461 treated cells was harvested after 3 hours, washed twice and incubated in drug free media. After second wash, cells were suspended in drug free medium and spun again. Resulting supernatant was collected and added to drug naïve cells (S) while the cells pellet was suspended in fresh media (w/o). B. Cell viability was measured immediately after washout and at day 1 and 3 with trypan blue staining. Experiment was performed three times and mean +/− S.D. is plotted. C. SEM cells were continuously incubated in DMSO or CX-5461 and a portion was harvested after 3 hours followed by washing in drug free media as before. Cell viability was measured using trypan blue staining at day 0, 1, 2 and 3 after washout. Results are plotted as mean +/− S.D. combination with CX-5461 then cells treated with single agent (Figure 6C). ABL inhibition [20, 21]. Dasatinib, a second-generation BCR-ABL kinase inhibitor, with a short half-life of approximately 3–5 hours has been shown to be clinically effective with once-daily administration despite only intermittent BCR-ABL inhibition [28]. More-over, tolerability of once-daily dosing was superior to the twice-daily schedule even with partial kinase inhibition. Recently, transient inhibition of PI3K in breast cancer cells was shown to be an effective therapeutic strategy [22]. UCN-01 treatment relieves cell-cycle arrest and shows enhanced cell killing in combination with CX-5461 In addition to transient treatment with CX-5461, we investigated other rational drug combinations that can potentiate the effect of continuous CX-5461 treatment. We have previously shown that CX-5461 activates ATM/ATR pathway in acute leukemia, arrests cells in G2 phase and synergizes with ATR inhibitor in killing these cells [19]. We hypothesized that abolishing cell-cycle arrest in the G2 phase would result in inadequate recovery from cellular stress and www.impactjournals.com/oncotarget Oncotarget 34850 mbination with CX-5461 then cells treated with single ent (Figure 6C). ABL inhibition [20, 21]. Dasatinib, a second-generation BCR-ABL kinase inhibitor, with a short half-life of gure 3: Washout procedure completely removes drug from the media. A. Schematic of drug treatment experiment in (b) M and NALM-6 cells were continuously treated with DMSO or with 250 or 500 nM CX-5461 (CX) respectively. A portion of CX-5461 ated cells was harvested after 3 hours, washed twice and incubated in drug free media. After second wash, cells were suspended in drug e medium and spun again. Resulting supernatant was collected and added to drug naïve cells (S) while the cells pellet was suspended in sh media (w/o). B. Cell viability was measured immediately after washout and at day 1 and 3 with trypan blue staining. Experiment was rformed three times and mean +/− S.D. is plotted. C. SEM cells were continuously incubated in DMSO or CX-5461 and a portion was rvested after 3 hours followed by washing in drug free media as before. Cell viability was measured using trypan blue staining at day 0 2 and 3 after washout. Results are plotted as mean +/− S.D. Figure 3: Washout procedure completely removes drug from the media. A. Schematic of drug treatment experiment in (b). SEM and NALM-6 cells were continuously treated with DMSO or with 250 or 500 nM CX-5461 (CX) respectively. A portion of CX-5461 treated cells was harvested after 3 hours, washed twice and incubated in drug free media. After second wash, cells were suspended in drug free medium and spun again. Resulting supernatant was collected and added to drug naïve cells (S) while the cells pellet was suspended in fresh media (w/o). B. Cell viability was measured immediately after washout and at day 1 and 3 with trypan blue staining. Experiment was performed three times and mean +/− S.D. is plotted. C. DISCUSSION In cancer therapy, continuous target inhibition has been seen as a pre-requisite for maximum clinical impact. Our results show that transient treatment with CX-5461 induces cellular changes similar to continuous treatment, albeit with a lag period. Importantly, after drug washout, cells are irreversibly committed to cell death despite complete recovery from rRNA synthesis inhibition. This suggests that short term blockade of rRNA synthesis is sufficient to irreversibly inhibit cellular proliferation. The rationale for continuous target inhibition for maximum efficacy has been challenged in chronic myeloid leukemia (CML). A series of studies have shown that cytotoxicity in CML cells can be achieved with transient potent BCR- Yung et al. [29] have reported that low dose actinomycin D treatment for short duration followed by washout leads to complete recovery of cell growth and rRNA synthesis, whereas higher dose or longer duration lead to irreversible inhibition of rRNA synthesis and cell proliferation. Recently, Ma et al. [30] showed similar results on cell-cycle arrest with actinomycin D treatment as seen with CX-5461. But in contrast to our results, they showed more than 80% inhibition of rRNA www.impactjournals.com/oncotarget Oncotarget 34851 synthesis at 20 hours post washout after a 2 and 4 hour actinomycin D treatment. Compared to their results, we achieved 50% inhibition in 3 hours with CX-5461. It is which intercalates into GC rich regions of rDNA and shows selectivity for RNA pol I at low dose. It inhibits Pol I transcription during the elongation step whereas Figure 4: UCN-01 relieves CX-5461 induced G2/M phase arrest. A. Cells were either treated with CX-5461 and UCN-01 alone or pretreated with 100 nM UCN-01 for 1 hour followed by 250 nM CX-5461 for 1 day. Cell-cycle distribution was determined by flow cytometry analysis of PI stained cells. UCN-01 completely removed G2/M block induced by CX-5461. One representative experiment out of three is shown. B. Cells were treated as in (a) and cell viability was measured at 55 hours post drug treatment using trypan blue staining. Combination treatment shows enhanced cytotoxicity compared to treatment with single agent. Experiment was repeated three times and mean +/− S.D. is plotted. Figure 4: UCN-01 relieves CX-5461 induced G2/M phase arrest. A. Cells were either treated with CX-5461 and UCN-01 alone or pretreated with 100 nM UCN-01 for 1 hour followed by 250 nM CX-5461 for 1 day. Cell-cycle distribution was determined by flow cytometry analysis of PI stained cells. DISCUSSION UCN-01 completely removed G2/M block induced by CX-5461. One representative experiment out of three is shown. B. Cells were treated as in (a) and cell viability was measured at 55 hours post drug treatment using trypan blue staining. Combination treatment shows enhanced cytotoxicity compared to treatment with single agent. Experiment was repeated three times and mean +/− S.D. is plotted. which intercalates into GC rich regions of rDNA and shows selectivity for RNA pol I at low dose. It inhibits Pol I transcription during the elongation step whereas CX-5461 disrupts the binding of the SL1 transcription factor to rDNA promoter, which inhibits initiation of rRNA synthesis by the Pol I complex. Nevertheless, in our case, recovery from rRNA synthesis after washout did not change the eventual fate of these cells. synthesis at 20 hours post washout after a 2 and 4 hour actinomycin D treatment. Compared to their results, we achieved 50% inhibition in 3 hours with CX-5461. It is possible that higher inhibition may lead to irreversible repression of rRNA synthesis. Another explanation may be the use of a solid cancer cell line in their study. This difference may also be due to a different mechanism of action. Actinomycin D is a RNA polymerase inhibitor www.impactjournals.com/oncotarget Oncotarget 34852 e 5: CX-5461 activates MAPK signaling pathway. A. SEM cells were treated with 250 nM CX-5461 or DMSO for 1 day. me profiler human phospho-kinase array was incubated with equal amount of control or drug treated sample. Results show an e in pERK (1), pCHK2 (2) and HSP60 (3) signal in CX-5461 treated cells compared to DMSO treated control. B. Increase in pERK was confirmed with western blot of CX-5461 treated SEM, NALM-6 and KOPN-8 cells. Adjusted relative density of pERK signal ized to corresponding DMSO treated control is indicated. Figure 5: CX-5461 activates MAPK signaling pathway. A. SEM cells were treated with 250 nM CX-5461 or DMSO for 1 day. Proteome profiler human phospho-kinase array was incubated with equal amount of control or drug treated sample. Results show an increase in pERK (1), pCHK2 (2) and HSP60 (3) signal in CX-5461 treated cells compared to DMSO treated control. B. Increase in pERK signal was confirmed with western blot of CX-5461 treated SEM, NALM-6 and KOPN-8 cells. Adjusted relative density of pERK signal normalized to corresponding DMSO treated control is indicated. Figure 5: CX-5461 activates MAPK signaling pathway. A. DISCUSSION SEM cells were treated with 250 nM CX-5461 or DMSO for 1 day. Proteome profiler human phospho-kinase array was incubated with equal amount of control or drug treated sample. Results show an increase in pERK (1), pCHK2 (2) and HSP60 (3) signal in CX-5461 treated cells compared to DMSO treated control. B. Increase in pERK signal was confirmed with western blot of CX-5461 treated SEM, NALM-6 and KOPN-8 cells. Adjusted relative density of pERK signal normalized to corresponding DMSO treated control is indicated. Figure 5: CX-5461 activates MAPK signaling pathway. A. SEM cells were treated with 250 nM CX-5461 or DMSO for 1 day. Proteome profiler human phospho-kinase array was incubated with equal amount of control or drug treated sample. Results show an increase in pERK (1), pCHK2 (2) and HSP60 (3) signal in CX-5461 treated cells compared to DMSO treated control. B. Increase in pERK signal was confirmed with western blot of CX-5461 treated SEM, NALM-6 and KOPN-8 cells. Adjusted relative density of pERK signal normalized to corresponding DMSO treated control is indicated. that provide evidence for a p53-independent mechanism that links nucleolar stress to inhibition of cell proliferation. We have previously shown that rRNA synthesis inhibition by CX-5461 activates ATM/ATR kinase pathway leading to CDC2 phosphorylation, G2 arrest and apoptosis in both p53 mutant and wild-type acute leukemia cells [19]. In line with that report, here we showed that p53 is activated upon 3 hours treatment in p53 wild-type cell line but the levels go down within 24 hours after drug washout suggesting p53-independent downstream effects of CX-5461. Donati et al. [33] showed that knockdown One of the most studied effects of nucleolar stress is the stabilization of p53 resulting in cell-cycle arrest and/or apoptosis [5]. ARF tumor suppressor has been shown to translocate to the nucleoplasm in response to nucleolar stress where it inhibits the binding of E3 ubiquitin ligase, MDM2, to p53 resulting in p53 stabilization [31]. Recent reports have shown that drugs targeting rRNA synthesis activate a p53-dependent apoptosis pathway in cancer cells displaying high rate of ribosome biogenesis [10, 32]. Although p53 activation upon ribosomal stress is well established, there are reports www.impactjournals.com/oncotarget Oncotarget 34853 Figure 6: MEK1/2 inhibitors enhance cytotoxicity of CX-5461. A. SEM cells were treated with 250 nM CX-5461 alone or 10 μM U-0126 alone or their combination. Western blot shows U-0126 reduced the levels of pERK induced by CX-5461 treatment. DISCUSSION B. SEM, KOPN-8 and NALM-6 cells were treated as in (a) and cell viability was measured using trypan blue staining at 55 hours. C. Cell lines were treated as in (a) but with another MEK1/2 inhibitor trametinib (150 nM Ttb). Combination treatment showed reduced viability in all three cell lines compared to single agent treated cells. (b, c) All experiments were repeated three times. Data represents mean +/− S.D. Figure 6: MEK1/2 inhibitors enhance cytotoxicity of CX-5461. A. SEM cells were treated with 250 nM CX-5461 alone or 10 μM U-0126 alone or their combination. Western blot shows U-0126 reduced the levels of pERK induced by CX-5461 treatment. B. SEM, KOPN-8 and NALM-6 cells were treated as in (a) and cell viability was measured using trypan blue staining at 55 hours. C. Cell lines were treated as in (a) but with another MEK1/2 inhibitor trametinib (150 nM Ttb). Combination treatment showed reduced viability in all three cell lines compared to single agent treated cells. (b, c) All experiments were repeated three times. Data represents mean +/− S.D. from the nucleolus [35]. One interesting question then is why transient inhibition of rRNA synthesis by CX-5461 affects cellular proliferation but suppression of rRNA synthesis during mitosis does not. We speculate that the untimely release of proteins sequestered in the nucleolus, upon drug treatment, results in cell-cycle arrest and apoptosis. For example, tumor suppressor protein ARF is sequestered in the nucleolus in association with NPM1 [36]. On nucleolar disruption by drug treatment or radiation, ARF translocates to the nucleoplasm, binds to E3 ligase MDM2 thereby preventing p53 ubiquitination. Elevated p53 levels then lead to cell-cycle arrest or apoptosis depending on the level of cellular insult [31]. Interestingly, ARF levels decrease during mitosis and recover in early G1 phase [37]. ARF has also been shown to inhibit growth in p53-independent manner by arresting cells in G2 phase which subsequently leads to apoptosis [38]. Also, we of POLR1A gene, which encodes the catalytic subunit of RNA polymerase I, in p53 null cells leads to cell-cycle arrest due to the down-regulation of transcription factor E2F-1. Ribosomal stress can also reduce the levels of PIM1 kinase leading to inhibition of cell proliferation in p53 null cells by stabilizing cell-cycle inhibitor p27kip1, a target of PIM1 kinase [34]. DISCUSSION This reduction in PIM1 levels can be seen as early as 3 hours after rRNA synthesis inhibition, a time frame similar to one used in this study. from the nucleolus [35]. One interesting question then is why transient inhibition of rRNA synthesis by CX-5461 affects cellular proliferation but suppression of rRNA synthesis during mitosis does not. We speculate that the untimely release of proteins sequestered in the nucleolus, upon drug treatment, results in cell-cycle arrest and apoptosis. For example, tumor suppressor protein ARF is sequestered in the nucleolus in association with NPM1 [36]. On nucleolar disruption by drug treatment or radiation, ARF translocates to the nucleoplasm, binds to E3 ligase MDM2 thereby preventing p53 ubiquitination. Elevated p53 levels then lead to cell-cycle arrest or apoptosis depending on the level of cellular insult [31]. Interestingly, ARF levels decrease during mitosis and recover in early G1 phase [37]. ARF has also been shown to inhibit growth in p53-independent manner by arresting cells in G2 phase which subsequently leads to apoptosis [38]. Also, we Many proteins involved in stress response, proliferation and cell-cycle progression are sequestered in the nucleolus (away from their site of action or interacting partners) thereby controlling their action [31]. At the onset of mitosis, rRNA synthesis is suppressed and nucleolus is disassembled in a highly regulated fashion. Many of the nucleolar proteins are phosphorylated by CDC2/Cyclin B complex (including members of rRNA synthesis and processing machinery) and are dissociated www.impactjournals.com/oncotarget Oncotarget 34854 ALL was based on morphology and flow cytometry data. Cytogenetic was determined by standard procedures. Cell lines and patient samples used in this study are cannot rule out the possibility that CX-5461 has other targets in the cells which stay inhibited even after drug removal. We have previously shown that caffeine and an ATR inhibitor can relieve CX-5461 induced G2 arrest, eventually leading to enhanced apoptosis [19]. Here, we showed that CX-5461 induced G2 arrest can be abolished by the checkpoint inhibitor UCN-01 [23, 26, 39] which also leads to enhanced cell death. This suggests that relieving G2 arrest by checkpoint kinase inhibitor UCN-01 provides no opportunity to the cells to overcome stress induced by CX-5461 treatment. As UCN-01 has been shown to enhance the cytotoxicity of radiation and chemotherapy, combination treatment with UCN-01 represents a therapeutic strategy that can potentiate the effectiveness of CX-5461 [40, 41]. Drug treatment and washout Cells were incubated with CX-5461 for indicated time. Cells were washed twice in culture media and reseeded in drug free media. For experiments with drug naïve cells, CX-5461 treated cells were washed twice and suspended in drug free media. The cells were centrifuged again, supernatant were collected and this supernatant was added to drug naïve cells (denoted as “S” in Figure 3B). Cell viability was measured using trypan blue staining or flow cytometry of PI stained cells. CX-5461 was purchased from Xcess Biosciences; UCN- 01 and U-0126 from Sigma-Aldrich; Trametinib from LC laboratories. Cell proliferation Cells were treated with DMSO or CX-5461 for 24  hours, washed twice and equal numbers of cells were seeded in 96 well plates. Cell proliferation was measured at 0 hour, 24 hours and 72 hours after washout using CellTiter 96 AQueous One Solution Cell Proliferation solution (MTS reagent) (Promega). MTS reagent was added to each well and incubated for 1 hour at 37oC in dark and absorbance was recorded at 490 nm using Bio-Rad microplate reader. Results were background subtracted and normalized to DMSO treated control. DISCUSSION More-over, CX-5461 treatment activates MAP kinase pathway and MEK inhibitors showed increased cell killing in combination with this rRNA synthesis inhibitor (Supplementary Figure 1C). In summary, our data suggests that transient inhibition of rRNA synthesis is sufficient to activate irreversible changes in cell survival and supports the potential for pulse treatment strategy in treating ALL with CX-5461, which in turn may minimize drug related toxicity. Also, we have provided in vitro evidence that rational combinations of CX-5461 with other inhibitors of survival pathways activated upon inhibition of rRNA synthesis can potentiate its effectiveness and should be further investigated in an in vivo model system. Phospho kinase proteome array and western blotting Scholar Program (P.B.). The Giant Food Pediatric Oncology Research Fund supported use of the FACSCalibur. Scholar Program (P.B.). The Giant Food Pediatric Oncology Research Fund supported use of the FACSCalibur. Phospho kinase levels were measured using Proteome Profiler Human Phospho-Kinase Array kit as suggested by the manufacturer (R&D System). Briefly, cells were lysed and protein concentrations were measured. Each phospho kinase array was incubated with 200 μg of protein lysate from DMSO or CX-5461 treated cells. Array was developed according to manufacturer’s instructions. For western blots, cell lysates were run on SDS Polyacrylamide gel and transferred to PVDF membrane. Membrane was blocked with 5% milk and incubated with primary antibody against ERK, Phospho-p44/42 MAPK (Erk1/2) (Thr202/Tyr204) and β-Tubulin. Antibodies were purchased from Cell Signaling Technology. Flow cytometry RS4;11, SEM, KOPN-8 and NALM-6 cell lines were purchased from German Collection of Microorganisms and Cell Cultures (DSMZ). Informed consent was obtained from patients, in accordance with the institutional review board guidelines, for the samples used in this study. Blasts were isolated from patient samples using Ficoll-Hypaque density gradient centrifugation and stored in liquid nitrogen for future use. The diagnosis of Cells were fixed in methanol and stored at −20oC until further processing. For cell-cycle analysis cells were spun down, washed in PBS and incubated in RNaseA containing propidium iodide (PI) solution at 37oC for 30 min in dark. Cells were run on BD FACScaliber (BD Biosciences) and cell-cycle analysis was performed using FlowJo software (Tree Star). Patient Sample Cyto-genotypes P1 MLL-AF4 P2 TEL-AML P3 MLL-ENL Cell Line Cyto-genotypes p53 status RS4;11 MLL-AF4 wild-type SEM MLL-AF4 mutant KOPN-8 MLL-ENL mutant NALM-6 t(5;12)(q33.2;p13.2) wild-type www.impactjournals.com/oncotarget www.impactjournals.com/oncotarget Oncotarget 34855 Authors declare no conflict of interest. Authors declare no conflict of interest. REFERENCES 1. Andersen JS, Lyon CE, Fox AH, Leung AK, Lam YW, Steen H, Mann M, Lamond AI. Directed proteomic analysis of the human nucleolus. Curr Biol. 2002; 12:1–11. 2. Scherl A, Coute Y, Deon C, Calle A, Kindbeiter K, Sanchez JC, Greco A, Hochstrasser D, Diaz JJ. Functional pro­ teomic analysis of human nucleolus. Mol Biol Cell. 2002; 13:4100–4109. qPCR 8. van Riggelen J, Yetil A, Felsher DW. MYC as a ­regulator of ribosome biogenesis and protein synthesis. Nat Rev Cancer. 2010; 10:301–309. Cells were treated with indicated concentrations of CX-5461. A portion of cells were harvested after 3 hours drug exposure and RNA was isolated. Rest of the cells were washed twice and reseeded in drug-free culture media. RNA was isolated, using RNeasy mini kit (Qiagen), from these cells after 24 hours. qPCR was performed using SYBR Green master mix and run on a CFX96 Bio-Rad real time PCR machine. Primer sequences for 45S pre-rRNA are forward 5′ CCGCGCTCTACCTTACCTACCT 3′, reverse 5′ GCATGGCTTAATCTTTGAGACAAG 3′; for βActin are forward 5′ CGTCACCAACTGGGACGACA 3′, reverse 5′ CTTCTCGCGGTTGGCCTTGG 3′. Experiments were repeated three times. Results were normalized to GAPDH and β Actin expression for each sample. 9. Hsieh AC, Truitt ML, Ruggero D. Oncogenic AKTivation of translation as a therapeutic target. Br J Cancer. 2011; 105:329–336. 10. Bywater MJ, Poortinga G, Sanij E, Hein N, Peck A, Cullinane C, Wall M, Cluse L, Drygin D, Anderes  K, Huser  N, Proffitt C, Bliesath J, et al. Inhibition of RNA polymerase I as a therapeutic strategy to promote ­cancer-specific activation of p53. Cancer Cell. 2012; 22:51–65. 11. Ruggero D. Revisiting the nucleolus: From marker to dynamic integrator of cancer signaling. Sci Signal. 2012; 5:pe38. 12. Hannan RD, Drygin D, Pearson RB. Targeting RNA ­polymerase I transcription and the nucleolus for cancer therapy. Expert Opin Ther Targets. 2013; 17:873–878. EU labeling of RNA transcript 3. Boisvert FM, van Koningsbruggen S, Navascués J, Lamond AI. The multifunctional nucleolus. Nat Rev Mol Cell Biol. 2007; 8:574–585. Pre-rRNA synthesis and processing of 45S transcript was determined by Click-iT® Nascent RNA Capture Kit (Life Technologies) according to manufacturer’s instructions [42]. Briefly, 0.4 mM ethynyl uridine (EU) was incorporated into SEM cells for 30 min. Cells were allowed to recover in EU free media and RNA was isolated at 0 and 3 hours after washout. EU-labeled RNA was biotinylated and captured on streptavidin magnetic beads according to the protocol. cDNA synthesis was performed directly on the beads. Relative levels of 45S pre-rRNA were measured by qPCR at each time point. All experiments were performed in triplicates. 4. James A, Wang Y, Raje H, Rosby R, DiMario P. Nucleolar stress with and without p53. Nucleus. 2014; 5:402–426. 5. Rubbi CP, Milner J. Disruption of the nucleolus mediates stabilization of p53 in response to DNA damage and other stresses. Embo j. 2003; 22:6068–6077. 6. White RJ. RNA polymerases I and III, growth control and cancer. Nat Rev Mol Cell Biol. 2005; 6:69–78. 7. Barna M, Pusic A, Zollo O, Costa M, Kondrashov N, Rego E, Rao PH, Ruggero D. Suppression of myc onco­ genic activity by ribosomal protein haploinsufficiency. Nature. 2008; 456:971–975. ACKNOWLEDGMENTS AND FUNDING 13. Peltonen K, Colis L, Liu H, Trivedi R, Moubarek MS, Moore HM, Bai B, Rudek MA, Bieberich CJ, Laiho M. A. targeting modality for destruction of RNA polymerase I that possesses anticancer activity. Cancer Cell. 2014; 25:77–90. This work was supported by grants from the Leukemia and Lymphoma Society Clinical Scholar Program (P.B.), and American Cancer Society Research www.impactjournals.com/oncotarget Oncotarget 34856 25. Bunch RT, Eastman A. Enhancement of cisplatin-induced cytotoxicity by 7-hydroxystaurosporine (UCN-01), a new G2-checkpoint inhibitor. Clin Cancer Res. 1996; 2:791–797. 14. Peltonen K, Colis L, Liu H, Jaamaa S, Zhang Z, Af Hallstrom T, Moore HM, Sirajuddin P, Laiho M. Small molecule BMH-compounds that inhibit RNA polymerase I and cause nucleolar stress. Mol Cancer Ther. 2014; 13:2537–2546. 26. Busby EC, Leistritz DF, Abraham RT, Karnitz  LM, Sarkaria  JN. The radiosensitizing agent 7-­hydroxystaurosporine (UCN-01) inhibits the DNA damage checkpoint kinase hChk1. Cancer Res. 2000; 60:2108–2112. 15. Colis L, Peltonen K, Sirajuddin P, Liu H, Sanders S, Ernst G, Barrow JC, Laiho M. DNA intercalator BMH-21 inhibits RNA polymerase I independent of DNA damage response. Oncotarget. 2014; 5:4361–4369. 16. Haddach M, Schwaebe MK, Michaux J, Nagasawa  J, O’Brien SE, Whitten JP, Pierre F, Kerdoncuff P, Darjania L, Stansfield R, Drygin D, Anderes K, Proffitt C, et al. Discovery of CX-5461, the first direct and selective inhibitor of RNA polymerase I, for cancer therapeutics. ACS Med Chem Lett. 2012; 3:602–606. 27. Tse AN, Carvajal R, Schwartz GK. Targeting checkpoint kinase 1 in cancer therapeutics. Clin Cancer Res. 2007; 13:1955–1960. 28. Shah NP, Kantarjian HM, Kim DW, Rea D, Dorlhiac-Llacer PE, Milone JH, Vela-Ojeda J, Silver RT, Khoury HJ, Charbonnier A, Khoroshko N, Paquette RL, Deininger M, et al. Intermittent target inhibition with dasatinib 100 mg once daily preserves efficacy and improves tolerability in imatinib-resistant and -intolerant chronic-phase chronic myeloid leukemia. J Clin Oncol. 2008; 26:3204–3212. 17. Drygin D, Lin A, Bliesath J, Ho CB, O’Brien SE, Proffitt C, Omori M, Haddach M, Schwaebe MK, Siddiqui-Jain A, Streiner N, Quin JE, Sanij E, et al. Targeting RNA poly­ merase I with an oral small molecule CX-5461 inhibits ­ribosomal RNA synthesis and solid tumor growth. Cancer Res. 2011; 71:1418–1430. 29. Yung BY, Bor AM, Chan PK. Short exposure to actino­ mycin D induces “reversible” translocation of ­protein B23 as well as “reversible” inhibition of cell growth and RNA synthesis in HeLa cells. Cancer Res. 1990; 50:5987–5991. 18. ACKNOWLEDGMENTS AND FUNDING Peltonen K, Colis L, Liu H, Jaamaa S, Moore HM, Enback  J, Laakkonen P, Vaahtokari A, Jones RJ, af  Hallstrom TM, Laiho M. Identification of novel p53 ­pathway activating small-molecule compounds reveals unexpected similarities with known therapeutic agents. PLoS One. 2010; 5:e12996. 30. Ma H, Pederson T. The nucleolus stress response is coupled to an ATR-Chk1-mediated G2 arrest. Mol Biol Cell. 2013; 24:1334–1342. 19. Negi SS, Brown P. rRNA synthesis inhibitor, CX-5461, activates ATM/ATR pathway in acute lymphoblastic ­leukemia, arrests cells in G2 phase and induces apoptosis. Oncotarget. 2015; 6:18094–18104. 31. Olson MO. Sensing cellular stress: Another new function for the nucleolus? Sci STKE. 2004; 2004:pe10. 32. Scala F, Brighenti E, Govoni M, Imbrogno E, Fornari F, Trere D, Montanaro L, Derenzini M. Direct relationship between the level of p53 stabilization induced by rRNA synthesis-inhibiting drugs and the cell ribosome biogenesis rate. Oncogene. 2015. doi: 10.1038/onc.2015.147. [Epub ahead of print] 20. Shah NP, Kasap C, Weier C, Balbas M, Nicoll JM, Bleickardt E, Nicaise C, Sawyers CL. Transient potent BCR-ABL inhibition is sufficient to commit chronic myeloid leukemia cells irreversibly to apoptosis. Cancer Cell. 2008; 14:485–493. 33. Donati G, Brighenti E, Vici M, Mazzini G, Trere D, Montanaro L, Derenzini M. Selective inhibition of rRNA transcription downregulates E2F-1: A new p53-independent mechanism linking cell growth to cell proliferation. J Cell Sci. 2011; 124:3017–3028. 21. Snead JL, O’Hare T, Adrian LT, Eide CA, Lange T, Druker BJ, Deininger MW. Acute dasatinib exposure ­commits bcr-abl-dependent cells to apoptosis. Blood. 2009; 114:3459–3463. 22. Will M, Qin AC, Toy W, Yao Z, Rodrik-Outmezguine V, Schneider C, Huang X, Monian P, Jiang X, de Stanchina E, Baselga J, Liu N, Chandarlapaty S, et al. Rapid ­induction of apoptosis by PI3K inhibitors is dependent upon their transient inhibition of RAS-ERK signaling. Cancer Discov. 2014; 4:334–347. 34. Iadevaia V, Caldarola S, Biondini L, Gismondi A, Karlsson  S, Dianzani I, Loreni F. PIM1 kinase is ­destabilized by ­ribosomal stress causing inhibition of cell cycle progression. Oncogene. 2010; 29:5490–5499. 35. Olson MO, Dundr M. The moving parts of the nucleolus. Histochem Cell Biol. 2005; 123:203–216. 23. Graves PR, Yu L, Schwarz JK, Gales J, Sausville EA, O’Connor PM, Piwnica-Worms H. The Chk1 protein kinase and the Cdc25C regulatory pathways are targets of the anti­ cancer agent UCN-01. J Biol Chem. 2000; 275:5600–5605. 36. Korgaonkar C, Hagen J, Tompkins V, Frazier AA, Allamargot C, Quelle FW, Quelle DE. www.impactjournals.com/oncotarget ACKNOWLEDGMENTS AND FUNDING Nucleophosmin (B23) targets ARF to nucleoli and inhibits its function. Mol Cell Biol. 2005; 25:1258–1271. 24. Hirose Y, Berger MS, Pieper RO. Abrogation of the Chk1-mediated G(2) checkpoint pathway potentiates temozolomide-induced toxicity in a p53-independent manner in human glioblastoma cells. Cancer Res. 2001; 61:5843–5849. 37. David-Pfeuty T, Nouvian-Dooghe Y. Human p14(arf): An exquisite sensor of morphological changes and of ­short-lived perturbations in cell cycle and in nucleolar ­function. Oncogene. 2002; 21:6779–6790. www.impactjournals.com/oncotarget Oncotarget 34857 with the checkpoint inhibitor UCN-01 involves disparate mechanisms resulting in either p53-independent clonogenic suppression or p53-dependent mitotic catastrophe. Cancer Res. 2004; 64:6635–6644. 38. Eymin B, Leduc C, Coll JL, Brambilla E, Gazzeri S. p14ARF induces G2 arrest and apoptosis independently of p53 leading to regression of tumours established in nude mice. Oncogene. 2003; 22:1822–1835. 39. Yu Q, La Rose J, Zhang H, Takemura H, Kohn KW, Pommier Y. UCN-01 inhibits p53 up-regulation and abrogates gamma-radiation-induced G(2)-M checkpoint independently of p53 by targeting both of the checkpoint kinases, Chk2 and Chk1. Cancer Res. 2002; 62:5743–5748. 41. Mack PC, Jones AA, Gustafsson MH, Gandara DR, Gumerlock PH, Goldberg Z. Enhancement of radiation cytotoxicity by UCN-01 in non-small cell lung carcinoma cells. Radiat Res. 2004; 162:623–634. 42. Jao CY, Salic A. Exploring RNA transcription and turnover in vivo by using click chemistry. Proc Natl Acad Sci U S A. 2008; 105:15779–15784. 40. Tse AN, Schwartz GK. Potentiation of cytotoxicity of topoi­ somerase i poison by concurrent and sequential treatment www.impactjournals.com/oncotarget Oncotarget 34858
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Modelling the emergence of cities and urban patterning using coupled integro-differential equations
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Research Cite this article: Whiteley TD, Avitabile D, Siebers P-O, Robinson D, Owen MR. 2022 Modelling the emergence of cities and urban patterning using coupled integro-differential equations. J. R. Soc. Interface 19: 20220176. https://doi.org/10.1098/rsif.2022.0176 Modelling the emergence of cities and urban patterning using coupled integro-differential equations royalsocietypublishing.org/journal/rsif royalsocietypublishing.org/journal/rsif Timothy D. Whiteley1, Daniele Avitabile4, Peer-Olaf Siebers2, Darren Robinson3 and Markus R. Owen1 Research 1School of Mathematical Sciences, University of Nottingham, Nottingham, UK 2School of Computer Science, University of Nottingham, Nottingham, UK 3School of Architecture, University of Sheffield, Sheffield, UK 4Department of Mathematics, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands TDW, 0000-0003-4990-4644; DA, 0000-0003-3714-7973; P-OS, 0000-0002-0603-5904; DR, 0000-0001-7680-9795; MRO, 0000-0002-3028-9138 School of Mathematical Sciences, University of Nottingham, Nottingham, U Cite this article: Whiteley TD, Avitabile D, Siebers P-O, Robinson D, Owen MR. 2022 Modelling the emergence of cities and urban patterning using coupled integro-differential equations. J. R. Soc. Interface 19: 20220176. https://doi.org/10.1098/rsif.2022.0176 2School of Computer Science, University of Nottingham, Nottingham, UK TDW, 0000-0003-4990-4644; DA, 0000-0003-3714-7973; P-OS, 0000-0002-0603-5904; DR, 0000-0001-7680-9795; MRO, 0000-0002-3028-9138 TDW, 0000-0003-4990-4644; DA, 0000-0003-3714-7973; P-OS, 0000-0002-0603-5904; DR, 0000-0001-7680-9795; MRO, 0000-0002-3028-9138 ownloaded from https://royalsocietypublishing.org/ on 05 May 2022 /royalsocietypublishing.org/ on 05 May 2022 Human residential population distributions show patterns of higher density clustering around local services such as shops and places of employment, dis- playing characteristic length scales; Fourier transforms and spatial autocorrelation show the length scale between UK cities is around 45 km. We use integro-differential equations to model the spatio-temporal dynamics of population and service density under the assumption that they benefit from spatial proximity, captured via spatial weight kernels. The system tends towards a well-mixed homogeneous state or a spatial pattern. Linear stability analysis around the homogeneous steady state predicts a modelled length- scale consistent with that observed in the data. Moreover, we show that spatial instability occurs only for perturbations with a sufficiently long wavelength and only where there is a sufficiently strong dependence of service potential on population density. Within urban centres, competition for space may cause services and population to be out of phase with one another, occupying separate parcels of land. By introducing competition, along with a preference for population to be located near, but not too near, to high service density areas, secondary out-of-phase patterns occur within the model, at a higher den- sity and with a shorter length scale than in phase patterning. Thus, we show that a small set of core behavioural ingredients can generate aggregations of populations and services, and pattern formation within cities, with length scales consistent with real-world data. The analysis and results are valid across a wide range of parameter values and functional forms in the model. Received: 4 March 2022 Accepted: 25 March 2022 1. Introduction The world is becoming increasingly urban. In 2007, the global urban population overtook the rural and, by 2050, two-thirds of the world population is expected to live in cities [1]. Cities are vitally important as hubs of business, commerce, social interaction and all the other necessary services that help us to survive. They are highly complex, resource consuming and self-organizing systems, as people are glued together by the services that support them but also pushed away by the problems that densification causes. Issues of urban density will affect transport networks, vehicle kilometres travelled [2], public transport feasibility [3] as well as social implications such as quality of life [4]. The existence and size of cities is a phenomenon largely driven from the bottom up, by the choices of individuals and firms. Yet mathematical patterns persist such as Zipf’s Law [5,6] which states that within a country or region, a city’s size is inversely proportional to its rank within that region. © 2022 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited. population density (pe km–2) 0–4000 4000–7000 7000–10 000 10 000–15 000 15 000+ 0 5 10 15 20 km Figure 1. Population density distribution in London from 2019 Population data [7], illustrating decreasing density overall with distance from the centre, with accompanying patchiness. Central London in particular displays a ‘density crater’ with lower population density due to the competing presence of commercial land use. Other patches are driven by commercial competition and other non-residential land use such as greenspace and parks. royalsocietypublishing.org/journal/rsif J. R. Soc. Interface 19: 20220176 2 R. Soc. Interface 19: 20220176 //royalsocietypublishing.org/ on 05 May 2022 nloaded from https://royalsocietypublishing.org/ on 05 May 2022 Figure 1. Population density distribution in London from 2019 Population data [7], illustrating decreasing density overall with distance from the centre, with accompanying patchiness. Central London in particular displays a ‘density crater’ with lower population density due to the competing presence of commercial land use. Other patches are driven by commercial competition and other non-residential land use such as greenspace and parks. Downloaded from https://royalsocietypublishing.or As a motivating example of population density within a UK city, we show a map of London in figure 1. This is an old city which has grown and absorbed many smaller towns around it over time. 2. Mathematical models for urban population density There is a global imperative to better understand how cities can be structured to function in more efficient and environmentally benign ways. To this end, we consider here the emergence of patterns of population density; the arrangement of people into and within cities. A mathematical model that supports emergent cities and subsequent second- ary patterning within the city may deepen our insights into how cities’ spatial structures emerge and, more importantly, reveal how these processes might be influenced. In 1951, Clark [8] proposed the empirical model that, exclud- ing the central business district (CBD), population density in cities declines exponentially with distance from the centre. Subsequently, Newling [9] suggested a revised quadratic exponential empirical model which captures the low central population density that corresponds to a city’s CBD. Bertaud [10] shows examples of nine world cities that display this characteristic profile. Newling postulated that as the popu- lation grows the parameters change to create and reinforce this central dip. In this paper, we will model and analyse the emergence of cities using an integro-differential equation approach, assum- ing a preference for people and services to locate near to each other, with distance dependence encapsulated in spatial weight kernels. Firstly, in §2, we will look at precedent models showing the value of differential equation-based modelling of cities and highlighting the scope for further work. In §3, we show how population density in parts of the UK demonstrates emergent length scales of 45  50 km between cities and, in appendix A, we show a length scale of 200 km between cities in the USA. This analysis provides the motivation for a new, explanatory, model developed in §4, which explains the emergence of population patterns. Linear stability analysis around the homogeneous steady state, a technique not yet applied in the urban modelling lit- erature, is used to predict emergent length scales from the model in §5. This model is developed further in §6 to show One key model of polycentric configurations and the interaction between households and firms is due to Fujita & Ogawa [11]. Their economic agglomeration-based model adapts Alonso’s well-known 1960s bid rent theory [12] where retail, manufacturing and residents compete for land; each having maximum bids for a given distance from the CBD. In Fujita and Ogawa’s model, land is occupied by population and firms. 1. Introduction There is a clear increase in popu- lation towards the city centre, and a notable population crater in the middle where services dominate. There are further areas of patchy residential patterning seen within the city as land uses such as parks, retail and industry outcompete population in certain areas. areas of within city structure, as population and services develop out-of-phase patterns. Lastly, in §7, we add popu- lation growth to the model to show how cities may grow and agglomerate, developing structure as they do. We con- clude with a discussion of our main findings and directions for future work in §8. Downloaded from https://royalsocietypublishing.org/ on 05 May 2022 ://royalsocietypublishing.org/ on 05 May 2022 Spatial autocorrelation is computed by comparing Moran’s I at a set of distances [32]. Moran’s I is a measure from −1 to 1 of the correlation of points separated by distance d. We group the set of pairs of LSOAs into those with cen- troid distance 0–1 km, 1–2 km, etc., and calculate the correlation of points in these groups. Alan Wilson’s entropy maximization [16] is a technique from transport modelling that has been adapted to model shopping power per location, considering monetary flows to predict sites with greatest potential for service growth. The transition from small corner shop to large supermarkets [17] is explained by modelling the advantage of larger floor area compared to the travel costs to such sites. Fry & Smith [18] recently extended this approach to develop a time-depen- dent model; they use entropy to define the profit of a configuration and hence drive growth of each retail location. Simplifications of their model allow asymptotic analysis on customer preference towards larger floor areas, showing a bifurcation from a homogeneous state where there are no differences between centre sizes, to a ‘winner takes all’ dynamic, whereby the centre with the original maximum size is the site that dominates the market. We calculate I(k) for the whole of England and Wales (encompassing 25 053 LSOAs), as well as showing the smaller regions of: the North West, including Manchester, Liverpool, Leeds, Sheffield and Nottingham (6712 LSOAs); and the region of Oxfordshire including Oxford, Swindon and Reading (1549 LSOAs) as can be seen on the map in figure 2. Secondly, we take a Fourier transform of a transect through the supporting regions. Taking a Fourier transform breaks the population density into a sum of sinusoidal waves and enables us to quantify the signal strength at each wavelength. We do this for a 140 km line through York- shire and the Midlands, encompassing Leeds, Sheffield, Nottingham and Leicester. This is compared with a second slice taken through Bristol, Swindon, Oxford and Luton. We calculate I(k) for the whole of England and Wales (encompassing 25 053 LSOAs), as well as showing the smaller regions of: the North West, including Manchester, Liverpool, Leeds, Sheffield and Nottingham (6712 LSOAs); and the region of Oxfordshire including Oxford, Swindon and Reading (1549 LSOAs) as can be seen on the map in figure 2. Downloaded from https://royalsocietypublishing.org/ on 05 May 2022 Secondly, we take a Fourier transform of a transect through the supporting regions. Taking a Fourier transform breaks the population density into a sum of sinusoidal waves and enables us to quantify the signal strength at each wavelength. We do this for a 140 km line through York- shire and the Midlands, encompassing Leeds, Sheffield, Nottingham and Leicester. This is compared with a second slice taken through Bristol, Swindon, Oxford and Luton. The results of both approaches can be seen in figure 2. In the North East region, we see a clear peak at a length of around 48 km and in Oxfordshire we see peaks at 43 km and 58 km. The Fourier transform shows similar dominant wavelengths in both regions of around 50 km. Lastly, a number of recent papers on a model of reaction– diffusion equations of population and wealth distribution have been released [19–21]. In their statistical analysis of the population landscape [19], the authors show spatial corre- lation across Canada, Australia and Mongolia that cannot be explained by environmental factors alone, highlighting the need for explanatory modelling. In all three papers, they model population wealth growth. Low and high incomes both give rise to lower growth of population, whereas growth in wealth increases with both increased wealth and increased population. In the non-spatial system, there are multiple steady states with complex bifurcations leading to sudden boom or collapse in the economy or popu- lation levels. In multiple dimensions, their stability analysis shows the emergence of characteristic length scales. As a brief comparison, appendix A shows similar analysis of length scales in the USA, which gives a longer character- istic length of around 200 km. Although these data are not entirely free from ambiguity, it shows that a characteristic length scale exists of around 45 km between cities in the UK and suggests that similar patterns but with different length scales may be found in different contexts. 2. Mathematical models for urban population density Households wish to maximize the commodities that they can gain from firms by balancing income, rent and travel costs while firms wish to maximize their profit by balancing the value gained by locating close to other businesses (captured by a weighted integral) against wage and rent costs. Hypothetical city structures are set up, and the parameters under which these are valid are analysed shape of a city may form [9,13], how multiple centres can dynamically emerge [15] and how to identify such transitions between equilibria [11]. In this paper, we uncover a set of underlying principles that can drive city formation and pat- terning, based on spatial kernels capturing distance preferences. We focus on the appearance of characteristic length scales and the emergence of complementary patterns, which is novel in the urban literature. to explain the possible equilibrium states of the system. They show that there may be both continuous and sudden struc- tural changes in the city dynamic at the boundaries of where an equilibrium is supportable. 3 royalsocietypublishing.org/journal/rsif J. R. Soc. Interface 19: 20220176 royalsocietypublishing.org/journal/rsif J. R. Soc. Interface 19: 20220176 In one of the first dynamic spatio-temporal models, Bracken & Tuckwell [13] used an integro-differential equation for population in one radial dimension. Their model has three terms: diffusion of population, logistic growth and an integral term that represents growth inhibition at distance r from the city centre. This integral is proportional to the total popu- lation between the city centre and r, emulating the negative impacts of travel congestion and increased house prices. 3. Length scales between cities We consider two methods to quantify the length scales between cities: two-dimensional spatial auto-correlation and the Fourier transform of a one-dimensional transect. These techniques are applied to UK Office for National Statistics (ONS) mid-2016 population density data for lower layer super output areas in England and Wales (LSOAs, average 1700 people) [31]. A more detailed and dynamical model of the growth of urban centres in a larger region was developed by Allen & Sanglier [14], building on their earlier work [15]. They pro- pose a model with logistic growth of population density at a set of discrete locations, with a carrying capacity at each location which depends on jobs of different types, and with migration from higher to lower densities (penalized by dis- tance moved). This model shows how interacting dynamics of population and jobs or services can produce centres of attraction; the resulting patterns always develop with population and jobs co-located in a self-reinforcing pattern. 4. Integro-differential equations for population and service dynamics Background mapping © Open street map con- tributors. (b) Autocorrelation for England and Wales, the North West and Oxfordshire regions showing a dominant length scale of 50 km and 43 km, respectively. (c) Fourier transform of the Yorkshire/Midlands and Oxfordshire lines both showing a characteristic length scale of 45–50 km. (b) (c) displacement (km) –0.10 –0.05 0 0.05 0.10 0.15 0.20 Moran's I autocorrelation North West Oxfordshire England and Wales 0 20 40 60 80 100 wavelength (km) 0 20 40 60 80 0 0.5 1.0 1.5 2.0 ×105 amplitude Fourier transform Yorkshire/Midlands Oxfordshire Figure 2. (a) A map of the population density of the UK showing the regions and lines analysed in this section. Background mapping © Open street map con- tributors. (b) Autocorrelation for England and Wales, the North West and Oxfordshire regions showing a dominant length scale of 50 km and 43 km, respectively. (c) Fourier transform of the Yorkshire/Midlands and Oxfordshire lines both showing a characteristic length scale of 45–50 km. (b) displacement (km) –0.10 –0.05 0 0.05 0.10 0.15 0.20 Moran's I autocorrelation North West Oxfordshire England and Wales 0 20 40 60 80 100 (c) wavelength (km) 0 20 40 60 80 0 0.5 1.0 1.5 2.0 ×105 amplitude Fourier transform Yorkshire/Midlands Oxfordshire (b) Downloaded from https://royalsocietypublish 1.5 amplitude Figure 2. (a) A map of the population density of the UK showing the regions and lines analysed in this section. Background mapping © Open street map con- tributors. (b) Autocorrelation for England and Wales, the North West and Oxfordshire regions showing a dominant length scale of 50 km and 43 km, respectively. (c) Fourier transform of the Yorkshire/Midlands and Oxfordshire lines both showing a characteristic length scale of 45–50 km. Here, is a weight kernel, which captures the non-local contri- bution of service density. We assume a Gaussian kernel with length scale β1, so data (table 1) and some cellular automata type models [22,24]. The model simulations will be in one or two spatial dimensions and the analysis is in one dimension. The differ- ence between one and two dimensions will be the spatial kernels and the ease of computation. 4. Integro-differential equations for population and service dynamics Since the 1980s, there has been a growth of bottom-up computational approaches to urban population modelling, without a corresponding development of mathematical theory to uncover general principles. Cellular automata [22– 24] and agent-based models [25–30] are powerful tools for simulating urban populations and for making data-driven predictions about the future state of a city, but they tend to lack explanatory power. On the other hand, parsimonious models of urban populations can show how the overall We model the spatio-temporal evolution of population den- sity p(x,t) (number of residents per square kilometre) and service fraction, s(x,t) (fraction of land occupied by services), at location x and time t. Here, we assume services include all providers of employment, leisure, retail, etc. Defining services via land use, as opposed to an abstract term such as utility, has the advantage of tying in both with available (b) (a) (c) displacement (km) –0.10 –0.05 0 0.05 0.10 0.15 0.20 Moran's I autocorrelation Yorkshire/Midlands Oxfordshire (line) Oxfordshire (region) North West region population density (people per square km) 2–346 346–1474 1474–2806 2806–4060 4060–5393 5393–7712 7712–93 469 North West Oxfordshire England and Wales 0 20 40 60 80 100 wavelength (km) 0 20 40 60 80 0 0.5 1.0 1.5 2.0 ×105 amplitude Fourier transform Yorkshire/Midlands Oxfordshire Figure 2. (a) A map of the population density of the UK showing the regions and lines analysed in this section. Background mapping © Open street map con- tributors. (b) Autocorrelation for England and Wales, the North West and Oxfordshire regions showing a dominant length scale of 50 km and 43 km, respectively. (c) Fourier transform of the Yorkshire/Midlands and Oxfordshire lines both showing a characteristic length scale of 45–50 km. royalsocietypublishing.org/journal/rsif J. R. Soc. Interface 19: 20220176 4 (a) Yorkshire/Midlands Oxfordshire (line) Oxfordshire (region) North West region population density (people per square km) 2–346 346–1474 1474–2806 2806–4060 4060–5393 5393–7712 7712–93 469 (a) Yorkshire/Midlands Oxfordshire (line) Oxfordshire (region) North West region population density (people per square km) 2–346 346–1474 1474–2806 2806–4060 4060–5393 5393–7712 7712–93 469 (a) (b) (c) displacement (km) –0.10 –0.05 0 0.05 0.10 0.15 0.20 Moran's I autocorrelation North West Oxfordshire England and Wales 0 20 40 60 80 100 wavelength (km) 0 20 40 60 80 0 0.5 1.0 1.5 2.0 ×105 amplitude Fourier transform Yorkshire/Midlands Oxfordshire Figure 2. (a) A map of the population density of the UK showing the regions and lines analysed in this section. 4. Integro-differential equations for population and service dynamics Average walk to shops is 1:1 km [33] b p2 length scale corresponding to how far population is willing to move to a more desirable location 10 km in 2013–2014, the median household move was in the ‘5-10 miles’ group [34] λ population scale parameter for the carrying capacity function, equation (4.10) 20000 pe km2 in London wards 0 < p < 14 000 [35] and 0 < s < 0.4 (assuming s to be non-domestic land use) [36]. If P = λ then s will be expected to approach σ(λ) = 1 −(1/e) ≈0.63 which is significantly higher than the value for s in London. Since σ(P) is an increasing function, this means that λ must be larger than the maximum population density in London. Selecting λ = 20 000 seems a reasonable estimate for this upper end of population density and service provision μ steepness parameter for the carrying capacity function 3 taking the mean of London wards gives p ¼ 8400 pe km2 [35] and s ¼ 0:06 (assuming s to be non-domestic land use) [36]. Using these values and solving the homogeneous steady-state equation (5.1) gives μ ≈3.2, assuming λ = 20 000 D rate of change of population density in an area 2 yr1 at the homogeneous state, the number of people who move in or out of a place is given by D · p0 · A0 = D · p0 · σ(p0) · (1 − σ(p0)). In London in 2018-19, flows in and out were approximately 290 pe km2 yr1 [37] and population density, p0, was approximately 5700 pe km2. This gives D ≈2.2 g speed of service followers per year 2 yr1 ignoring f, ds/dt is at its maximum value when σ = 1 and s = 0.5, giving ds/dt = 0.25g. At this rate it will take 2/g years for s to reach σ = 1. g = 2 (1 year) seems a sensible timescale for this maximal rate f speed of service innovators per year 0:05 yr1 we assume that change is mostly driven by logistic growth and therefore service innovation is slower than service followers. If s = 0, ds/dt = f · σ(p). 4. Integro-differential equations for population and service dynamics At this rate it would take 1 f ¼ 20 years to reach the steady state Downloaded from https://royalsocietypublishing.org/ on 05 May 2022 parameter definition default value justification βs length scale for the kernel ws, characterizes how close services wish customers to be 5 km mean trip distance to shopping in an urban conurbation is 4:7 km [33] b p1 length scale used in kernel w p1 corresponding to how near population wishes to be to services 1 km assume attraction of an area is given by local services; those within walking distance. Average walk to shops is 1:1 km [33] b p2 length scale corresponding to how far population is willing to move to a more desirable location 10 km in 2013–2014, the median household move was in the ‘5-10 miles’ group [34] λ population scale parameter for the carrying capacity function, equation (4.10) 20000 pe km2 in London wards 0 < p < 14 000 [35] and 0 < s < 0.4 (assuming s to be non-domestic land use) [36]. If P = λ then s will be expected to approach σ(λ) = 1 −(1/e) ≈0.63 which is significantly higher than the value for s in London. Since σ(P) is an increasing function, this means that λ must be larger than the maximum population density in London. Selecting λ = 20 000 seems a reasonable estimate for this upper end of population density and service provision μ steepness parameter for the carrying capacity function 3 taking the mean of London wards gives p ¼ 8400 pe km2 [35] and s ¼ 0:06 (assuming s to be non-domestic land use) [36]. Using these values and solving the homogeneous steady-state equation (5.1) gives μ ≈3.2, assuming λ = 20 000 D rate of change of population density in an area 2 yr1 at the homogeneous state, the number of people who move in or out of a place is given by D · p0 · A0 = D · p0 · σ(p0) · (1 − σ(p0)). In London in 2018-19, flows in and out were approximately 290 pe km2 yr1 [37] and population density, p0, was approximately 5700 pe km2. This gives D ≈2.2 g speed of service followers per year 2 yr1 ignoring f, ds/dt is at its maximum value when σ = 1 and s = 0.5, giving ds/dt = 0.25g. 4. Integro-differential equations for population and service dynamics w p1ðxÞ ¼ Gðx, b1Þ, ð4:3Þ ð4:3Þ We begin by defining a notion of attractiveness to the residen- tial population, A(x,t), which captures the assumptions that a location is more attractive if there are services near to that place, but less attractive if the location is itself full of services (people may not want to reside in areas of dense service pro- vision). A is then given as the product of a non-local average of service fraction and the local fraction of non-service space where Gðx, bÞ ¼ 1 b ffiffiffiffiffiffi 2p p eðx2=2b2Þ (In 1D) Gðx, bÞ ¼ 1 2pb2 eðjxj2=2b2Þ (In 2D) 9 > > > = > > > ; and ð4:1Þ Aðx, tÞ ¼ AðSðx, tÞ, sðx, tÞÞ ¼ Sðx, tÞð1  sðx, tÞÞ, ð4:1Þ Such a kernel means that points that are further away from x Such a kernel means that points that are further away from x have less influence than points near x. It is used elsewhere in the urban modelling literature [16,38]. The rate of decay is given by β where larger β gives a more spread shape, synony- mously with the standard deviation of a normal distribution. where where Sðx, tÞ ¼ ð w p1ðx  yÞsðy, tÞdy ¼ w p1sðx, tÞ: Sðx, tÞ ¼ ð w p1ðx  yÞsðy, tÞdy ¼ w p1sðx, tÞ: ð4:2Þ ð4:2Þ Table 1. Table of parameters corresponding to equations (4.1) to (4.10) that define dp/dt and ds/dt. These parameters are based on UK data from publicly available data sources. Table 1. Table of parameters corresponding to equations (4.1) to (4.10) that define dp/dt and ds/dt. These parameters are based on UK data from publicly available data sources. 5 5 parameter definition default value justification βs length scale for the kernel ws, characterizes how close services wish customers to be 5 km mean trip distance to shopping in an urban conurbation is 4:7 km [33] b p1 length scale used in kernel w p1 corresponding to how near population wishes to be to services 1 km assume attraction of an area is given by local services; those within walking distance. 5. Spatial instability leads to patterned steady states The sigmoidal form would model a situation in which, at low populations, the benefits of setting up a business barely exceed the fixed costs and service carrying capacity increases weakly. As the population increases, there may be a tipping point where the benefits gained increasingly out- weigh the costs, leading to a marked steepening of the carrying capacity function, which then levels off as the population approaches saturation. Downloaded from https://royalsocietypubl _p _s   ¼ Jðp0, s0, kÞ p s   ð5:4Þ ð5:4Þ so that we can analyse the stability matrix J. Calculation of J can be found in appendix C.1, giving Jð p0; s0; kÞ ¼ Ds0ð1  s0Þð1  ^w p2ðkÞÞ Dp0ð1  ^w p2ðkÞÞ ðð1  s0Þ^w p1ðkÞ  s0Þ ð f þ gs0Þs0ð p0Þ^wsðkÞ ð f þ gs0Þ 2 64 3 75: ð5:5Þ ð5:5Þ For each frequency, k, perturbations are unstable if at least one eigenvalue of J(k) has positive real part. We plot the real part of the leading eigenvalue against spatial frequency in dispersion relations to see the modes with a positive growth rate. We plot these dispersion relations as we vary the average population in the model in figure 4a. For simplicity, we assume initially that there will be no growth of the total population. Instead, we will analyse how the steady states of this model depend on the total population. This shows that for small populations, modes of lower fre- quency grow, but higher frequency, shorter wavelength modes dissipate. As population density increases, the fastest growing mode moves from five peaks in the domain (40 km wavelength) to 2–3 peaks (60–100 km). For larger population densities, the dispersion relation predicts that all pertur- bations will dissipate. Equations (4.4) and (4.6) give a description of the spatio- temporal interaction between population and services. A dia- gram explaining these interactions can be seen in figure 3a. Explanations and estimates for the default parameters corre- sponding to UK data are given in table 1. Numerical methods are explained in appendix B. Simulations of the model with the kernels and parameters listed show that the system tends either to a spatially homo- geneous state, where population and services are completely mixed, or spatial patterns emerge. These patterns take the form of areas of increased population and service density, as shown in figure 3b. An initial homogeneous population is seeded with small random perturbations. 5. Spatial instability leads to patterned steady states We wish to understand the conditions in which a homo- geneous steady state or a spatial pattern emerge. For any homogeneous {p0, s0}, equation (4.4) will be zero and there- fore the homogeneous steady state for p is p0 ¼ p, the average population density, which is dictated by the initial conditions. Equation (4.6) gives the homogeneous steady state for s as Pðx, tÞ ¼ ws  pðx, tÞ: ð4:7Þ ð4:7Þ We assume the spatial weight kernel ws is Gaussian; specifically s0 ¼ sðp0Þ: ð5:1Þ ownloaded from https://royalsocietypublishing.org/ on 05 May 2022 ð5:1Þ Downloaded from https://royalsocietypublishing.org/ on 05 May 2022 https://royalsocietypublishing.org/ on 05 May 2022 wsðxÞ ¼ Gðx, bsÞ: ð4:8Þ ð4:8Þ To better understand which wavelengths we expect to emerge from an unstable homogeneous state, we consider the perturbation from the steady state From the definition of s(x,t) being the fraction of land occupied by services, we require 0 ≤s ≤1 and so 0 ≤σ ≤1 also. It is natural to expect that the greater the popula- tion near x, the more services can be supported at x by this population, therefore σ(P) should be a non-decreasing function. We assume that carrying capacity for services will take the form From the definition of s(x,t) being the fraction of land occupied by services, we require 0 ≤s ≤1 and so 0 ≤σ ≤1 also. It is natural to expect that the greater the popula- tion near x, the more services can be supported at x by this population, therefore σ(P) should be a non-decreasing function. We assume that carrying capacity for services will take the form p ¼ p0 þ ~pðx, tÞ, s ¼ s0 þ ~sðx, tÞ: ð5:2Þ ð5:2Þ In particular, we look for Turing-like instabilities; that is by looking at sinusoidal perturbations of frequency k, given by f~pðx, tÞ, ~sðx, tÞg ¼ fpðtÞ eikx, sðtÞ eikxg: ð5:3Þ ð5:3Þ sðPÞ ¼ 1  e(P=l)m: ð4:9Þ ð4:9Þ Linearizing, we obtain a problem of the form Linearizing, we obtain a problem of the form This function has the features that σ(0) = 0, lim p→∞σ( p) = 1 and dσ/dP > 0. σ can be understood as the potential for service provision for a given population. The parameter λ represents the population scale and μ represents the shape of the function. If μ ≤1 this function is concave and if μ > 1 it is sigmoidal with maximum steepness increasing with μ. 4. Integro-differential equations for population and service dynamics The length scale of the pattern is 53 km according to the spatial autocorrelation (figure 3c). 6 royalsocietypublishing.org/journal/rsif J. R. Soc. Interface 19: 20220176 ds dt ðx, tÞ ¼ ðf þ gsÞ(sðPÞ  s): ð4:6Þ ð4:6Þ The rates f and g represent the speed of service innova- tors and imitators respectively. The carrying capacity for services for a given population density is σ(P(x,t)). P(x,t) is a weighted integral of p(x,t), where the third and final kernel in the model, ws, encapsulates dependence of the carrying capacity on the population distribution. The kernel here captures the typical distance residents travel to places of work, retailers and other services. The equation for P(x,t) is The rates f and g represent the speed of service innova- tors and imitators respectively. The carrying capacity for services for a given population density is σ(P(x,t)). P(x,t) is a weighted integral of p(x,t), where the third and final kernel in the model, ws, encapsulates dependence of the carrying capacity on the population distribution. The kernel here captures the typical distance residents travel to places of work, retailers and other services. The equation for P(x,t) is 4. Integro-differential equations for population and service dynamics At this rate it will take 2/g years for s to reach σ = 1. g = 2 (1 year) seems a sensible timescale for this maximal rate f speed of service innovators per year 0:05 yr1 we assume that change is mostly driven by logistic growth and therefore service innovation is slower than service followers. If s = 0, ds/dt = f · σ(p). At this rate it would take 1 f ¼ 20 years to reach the steady state Downloaded from https://royalsocietypublishing.org/ on 05 May 2022 ://royalsocietypublishing.org/ on 05 May 2022 p0, was approximately 5700 pe km2. This gives D ≈2.2 ignoring f, ds/dt is at its maximum value when σ = 1 and s = 0.5, giving ds/dt = 0.25g. At this rate it will take 2/g years for s to reach σ = 1. g = 2 (1 year) seems a sensible timescale for this maximal rate where D measures the overall rate of moving and The parameter β1 therefore characterizes how near the residential population wishes to be to services. w p2ðxÞ ¼ Gðx, b2Þ, ð4:5Þ ð4:5Þ We then assume that the rate of population movement from location y to x is proportional to the attractiveness of x multiplied by the density of potential movers at y and weighted according to the distance between the locations (short distance moves being more likely [34]). The rate of change in population at a location x will therefore be given by the rate of moving from all other locations y to x (moves into x), minus the rate of moving from x to all other locations y (moves out of x): gives a Gaussian dependence of the rate on the distance moved. The dynamics of the service fraction, s(x,t), is assumed to be driven by a demand that is an increasing function of the residential population that can access services at x. Growth in the service fraction is therefore driven by innovators that start new businesses when demand exceeds supply, and expansion of existing businesses, imitators. However, if supply exceeds demand, then competition would force dp dt ðx, tÞ ¼ D ð ½AðxÞpðyÞ  AðyÞpðxÞw p2ðx  yÞ dy, ð4:4Þ ð4:4Þ some out of business. We have Continuing the simulation to 150 years shows solidification of the city structure occurring as people move to the city. 5. Spatial instability leads to patterned steady states After 50 years, we start to see some areas growing more than others and, by 100 years, clear city structures have formed. The largest cities have a slight density crater in the city centre. We can further analyse this Jacobian to calculate con- ditions for any wavelengths to be unstable. We show in appendix C.1.1 that there are unstable frequencies if and only if s0ð1  s0Þ p0s0ðp0Þ þ s0 , ð1  s0Þ, ð5:6Þ ð5:6Þ and that, if this holds, then instability occurs in a window (0, kc) for some critical frequency kc. (a) (b) (c) (–) logistic growth (+) carrying capacity (–) movement (+) attraction non-local interaction local interaction services, s population, p –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 0.5 1.0 1.5 2.0 ×104 0.1 0.2 0.3 0.4 0.5 0.6 population density, p 0 Moran’s I 50 100 distance (km) distance (km) time = 0 years time = 50 years time = 100 years time = 150 years distance (km) distance (km) –100 –50 0 50 distance (km) service density, s –100 –50 0 50 distance (km) –100 –50 0 50 distance (km) 150 –0.2 0 0.2 e 3. Emergence of cities from an initial random population distribution. (a) The key interactions in the model. p and s represent population and services at a Blue lines represent non-local dynamics, that is where a spatial convolution is used to characterize the influence of a distribution in the neighbourhood around nt. (b) We initialize a population of p = 8000 + 1000r, where r ∼N(0, 1). After 100 years, we see the clear emergence of city structures, which are further thened at 150 years. (c) The length scale between these cities is around 53 km as can be seen in the autocorrelation plot of the final simulation. Parameters pond to the default parameters in table 1. (a) (–) logistic growth (+) carrying capacity (–) movement (+) attraction non-local interaction local interaction services, s population, p royalsocietypublishing.org/journ 7 royalsocietypublishing.org/journal/rsif J. R. Soc. 5. Spatial instability leads to patterned steady states Interface 19: 20220176 7 (a) (b) (–) logistic growth (+) carrying capacity (–) movement non-local interaction local interaction services, s population, p –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 0.5 1.0 1.5 2.0 ×104 population density, p time = 0 years time = 50 years time = 100 years time = 150 years distance (km) (–) logistic growth population, p (b) population density, p 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 0.5 1.0 1.5 2.0 ×104 pulation density, p ars time = 100 years time = 150 years –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 0.1 0.2 0.3 0.4 0.5 0.6 distance (km) distance (km) –100 –50 0 50 distance (km) service density, s –100 –50 0 50 distance (km) –100 –50 0 50 distance (km) –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 distance (km) ( ) –100 –50 0 50 distance (km) service density, s –100 –50 0 50 distance (km) service density, s –100 –50 0 50 0.1 0.2 0.3 0.4 0.5 0.6 –100 –50 0 50 distance (km) (c) 0 Moran’s I 50 100 distance (km) 150 –0.2 0 0.2 distance (km) Figure 3. Emergence of cities from an initial random population distribution. (a) The key interactions in the model. p and s represent population and services at a point. Blue lines represent non-local dynamics, that is where a spatial convolution is used to characterize the influence of a distribution in the neighbourhood around a point. (b) We initialize a population of p = 8000 + 1000r, where r ∼N(0, 1). After 100 years, we see the clear emergence of city structures, which are further strengthened at 150 years. (c) The length scale between these cities is around 53 km as can be seen in the autocorrelation plot of the final simulation. Parameters correspond to the default parameters in table 1. For a more general σ(p), if equation (5.6) holds, we must have p0σ0(p0) > s0 = σ(p0). 5. Spatial instability leads to patterned steady states Although technical exceptions can be found, this suggests that σ should be convex on (0, p0) for instabilities to the homogeneous steady state to arise. This model analysis predicts that when service potential is highly reactive to a change in population (convex σ(p)) then we expect pattern generating instabilities to arise. Conversely, if a change in population does not drive a sufficient reaction in ser- vice potential then we expect such a perturbation to die away. We can solve for equality in (5.6) using (5.1) to find the bifurcation point at which spatial instability arises, {p0, s0}. For the carrying capacity function given by equation (4.9), the bifurcation point in s occurs at the solution of s0 = μ (2s0 −1) ln(1 −s0). The bifurcation point depends only on μ and the equation has a solution for μ ≥1. The parameter μ is the steepness of the change in carrying capacity for services for a change in population. It is concave with respect to population density if μ < 1 and sigmoidal other- wise. Using the value of μ = 3 in figure 4, we calculate s0 = 0.37, p0 = 15 360 for the bifurcation point. Moreover, if equation (5.6) holds and there are instabilities of the homogeneous steady state, then . Regardless of the 0 0.1 0.2 0.3 0.4 0.5 –0.08 –0.06 –0.04 –0.02 growth rate (real part of leading eigenvalue) maximum service provision, spatial frequency, k average population density, p 0 0.02 0.04 0.06 (a) (c) (b) average population density p = 5000 s (x) p = 13 620 p = 14 743 p = 15 360 p = 17 000 0.5 1.0 1.5 2.0 2.5 ×104 3.0 homogeneous solution 1 city in domain 2 cities 3 cities 4 cities 5 cities 6 cities 7 cities 8 cities 0 0.2 0.4 0.6 0.8 1.0 population density service density 2.0 0.6 2000 1500 1000 500 0 2000 1500 1000 500 0 –100 0 100 –100 0 distance (km) distance (km) 100 0.5 0.4 0.3 0.2 0.1 1.5 1.0 time (years) 0.5 ×104 Figure 4. (a) Dispersion relations at five different values of the average population, p. The crosses correspond to the different wavenumbers. This diagram shows which spatial frequencies are unstable; the larger the real part of the eigenvalue, the more destabilizing that frequency. 5. Spatial instability leads to patterned steady states Interface 19: 20220176 8 maximum service provision, average population density, p (b) s (x) 0.5 1.0 1.5 2.0 2.5 ×104 3.0 homogeneous solution 1 city in domain 2 cities 3 cities 4 cities 5 cities 6 cities 7 cities 8 cities 0 0.2 0.4 0.6 0.8 1.0 8 (a) maximum service provision, s (x maximum service provis population density 2.0 2000 1500 1000 500 0 –100 0 distance (km) 100 1.5 1.0 time (years) 0.5 ×104 service density 0.6 2000 1500 1000 500 0 –100 0 100 distance (km) 0.5 0.4 0.3 0.2 0.1 (c) Downloaded from https://royalsocietypublishing.org/ on 05 time (years) Downloaded from https://royalsocietypublish Figure 4. (a) Dispersion relations at five different values of the average population, p. The crosses correspond to the different wavenumbers. This diagram shows which spatial frequencies are unstable; the larger the real part of the eigenvalue, the more destabilizing that frequency. As population density p increases, the length scale of the dominant unstable wavelength increases from around 40 km (k ¼ 0:15) to around 60 km (k ¼ 0:1). At p ¼ 15 360, the dispersion relation is tangential to the horizontal at k = 0. This is the bifurcation point where no modes are unstable. At p . 15 360 any perturbation decays. (b) Bifurcation diagram showing where patterned steady states exist as average population density varies. Thick lines correspond to stable solutions and thin lines correspond to unstable solutions. The stable branch is the single city solution, but other branches display metastability. (c) Time simulation showing how a seven bump metastable steady state suddenly transitions into a three bump state after a very long time period. The three bump solution is itself metastable but persists for any reasonable timescales. Initial conditions were p(x,0) = 10000 + 5000 cos (7πx/100) with s(x,0) = σ( p(x,0)). in which a patterned state can exist and to explore the bifur- cation points. This can be seen in figure 4b. The patterned states emerge at low average populations until a series of bifurcation points where each becomes stable. The last bifur- cation to the homogeneous state is at confirming what we saw with the dispersion relation. Between p ¼ 15 360 and p ¼ 18 000, both the homogeneous steady state and the pat- terned state are stable and for p . 18 000 only the homogeneous state is stable. 5. Spatial instability leads to patterned steady states As population density p increases, the length scale of the dominant unstable wavelength increases from around 40 km (k ¼ 0:15) to around 60 km (k ¼ 0:1). At p ¼ 15 360, the dispersion relation is tangential to the horizontal at k = 0. This is the bifurcation point where no modes are unstable. At p . 15 360 any perturbation decays. (b) Bifurcation diagram showing where patterned steady states exist as average population density varies. Thick lines correspond to stable solutions and thin lines correspond to unstable solutions. The stable branch is the single city solution, but other branches display metastability. (c) Time simulation showing how a seven bump metastable steady state suddenly transitions into a three bump state after a very long time period. The three bump solution is itself metastable but persists for any reasonable timescales Initial conditions were p(x 0) = 10000 + 5000 cos (7πx/100) with s(x 0) = σ( p(x 0)) 0 0.1 0.2 0.3 0.4 0.5 –0.08 –0.06 –0.04 –0.02 growth rate (real part of leading eigenvalue) maximum service provision, spatial frequency, k average population density, p 0 0.02 0.04 0.06 (a) (b) average population density p = 5000 s (x) p = 13 620 p = 14 743 p = 15 360 p = 17 000 0.5 1.0 1.5 2.0 2.5 ×104 3.0 homogeneous solution 1 city in domain 2 cities 3 cities 4 cities 5 cities 6 cities 7 cities 8 cities 0 0.2 0.4 0.6 0.8 1.0 0 0.1 0.2 0.3 0.4 0.5 –0.08 –0.06 –0.04 –0.02 growth rate (real part of leading eigenvalue) spatial frequency, k 0 0.02 0.04 0.06 (a) average population density p = 5000 p = 13 620 p = 14 743 p = 15 360 p = 17 000 royalsocietypublishing.org/journal/rsif J. R. Soc. 5. Spatial instability leads to patterned steady states carrying capacity function, instability can only occur where we have sufficiently small population densities and services. If the population is too high, the model predicts that there would be urban sprawl rather than further agglomeration. We can also see that for a solution to be unstable to a certain perturbation, that perturbation must have a sufficien- tly long wavelength. In an urban context, this means that we do not expect to see lots of very small but high-density cities next to each other. In this case, we expect agglomeration would occur. However, if cities are far enough apart, we can expect them to remain distinct. Figure 4b suggests that the only stable patterned state is the single cluster pattern. This is due to the presence of meta- stable steady states, where the instability can only be seen by simulating the system for an extreme length of time, as in figure 4c. All the multi-peak branches display this metastabil- ity. However, the timescales at which this agglomeration occurs might be of the order of greater than a millennium or even more and these steady states are therefore only very weakly unstable. Having analysed the homogeneous steady state, we can now look at the patterned steady states and determine their stability. These can be calculated using a process of numerical continuation [39]. Beginning with a steady state produced by simulation, we track how this state changes as we vary the average population size, p. This allows us to see the regions Table 2. Supplement to table 1. Additional parameters for equations (6.1) and (6.2). parameter definition default value justification ap secondary length scale used in kernel w p1 corresponding to the population’s preferred distance to services 1:5 km given b p1 ¼ 1 km, ap = 1.5 creates distinct, off centre, peaks without separating the two Gaussians completely α1 competition parameter. How much space does each person take away from services 1.5 × 10−5 km2 pe1 when population dominates, α1 p = 1. In London wards, the maximum population density is 28 863 pe km2 which would give a1 ¼ 3:53  105 km2 pe1. We assume less competition than this [35] Table 2. Supplement to table 1. Additional parameters for equations (6.1) and (6.2). royalsocietypublishing.org/journal/rsif J. R. Soc. Interface 19: 20220176 9 Soc. 5. Spatial instability leads to patterned steady states Interface 19: 20220176 We have shown how distinct cities can form where the average population density is sufficiently low and there is sufficient reaction by services to a change in population. Unstable perturbations to the homogeneous steady state must be of sufficiently long length scale showing how we expect agglomeration to occur over longer rather than shorter distances. The dominant unstable wavelength of such perturbations can be seen in the dispersion relations given by the linear stability analysis of the steady state. We also saw the presence of bifurcation points and metastable steady states in the system which shows how sudden agglom- eration may occur, particularly as population increases. With competition now included, the space requirements of people can overcome the potential for service growth so we assume that if there is no potential for service growth then there are no innovators, f. This is why we have a factor of H(σ(P) −(s + α1p)), where H is the Heaviside step function. Importantly, this ensures that s = 0 is a lower bound for ser- vices. The default values for the new parameters ap and α1 can now be found in table 2. Downloaded from https://royalsocietypublishing.org/ on 05 May 2022 Including competition can give both in-phase and out-of- phase patterning at different spatial scales (figure 5a,b). In- phase patterns are the co-location of high-densities of people and services, such as seen on a large scale in cities. Out-of-phase patterns are where people and services occupy distinct and complementary areas; here they typically have shorter length scales and occur as secondary structures within cities. Downloaded from https://royalsocietypub 6. Secondary patterning when services compete for space and residents avoid high service d i In this example, a three bump solution with no secondary pattern (figure 5a) persists at the same parameter values as a two bump solution with shorter wavelength secondary pat- terning within each bump (figure 5b). This secondary pattern has a wavelength of around 5 km. London in figure 1 shows an example of multiple patterning. Firstly, aggregation brings people and services together to form thecityitselfandthereisagrowthinpopulationdensitytowards the city centre. However, there is secondary patchy patterning on top of this framework. This may be driven by people and ser- vices occupying distinct areas (one is high when the other is low)—seen in particular at the centre of the city. In order to understand the emergent length scales, we again use linear stability analysis around the homogeneous steady state, {p0, s0}. The steady state for p is given by p0 ¼ p, the average population density which is dictated by initial conditions. For smaller population densities (p , 11 500), we have that σ( p0) < α1p0 and so the spatially homogeneous steady state is p0 ¼ p, s0 = 0. There will not be sufficient demand for services to overcome the compe- tition for space and so no services can be supported. Patterned states can exist with these average population den- sities but they are not emergent from the homogeneous steady state. Instead, they would have to emerge from different initial conditions. Within our model framework, we make two further assumptions. We assume that people’s desire is to locate ‘near but not too near’ to the services that support their needs; and that there is competition for space between people and services within cities. The first assumption about people’s location choice can be built into kernel w p1 by using a Gaussian kernel that has been shifted off centre by distance ap in each direction and then summed For p . 11 500, we have that σ( p0) > α1p0 and the steady state is w p1ðxÞ ¼ 1 2 (Gðx þ ap, b p1Þ þ Gðx  ap, b p1ÞÞ: ð6:1Þ ð6:1Þ p0 ¼ p, s0 ¼ sðp0Þ  a1p0: ð6:3Þ ð6:3Þ G is the Gaussian previously defined in equation (4.4). This assumes that there is an ideal distance ap which people wish to be from service locations. Moreover, competition is introduced into equation (4.6) as services compete for space with residents. 6. Secondary patterning when services compete for space and residents avoid high service d i (a,b) Example simulations showing how in-phase and out-of-phase patterning are possible. Both have the same parameters and mean population p ¼ 16 000, with α1 = 1.3 × 10−5. Initial conditions can be seen in figure 11. (c) Dispersion relations for different values of the average population, p. At low populations, there is not sufficient service potential to overcome competition for space so no instability can persist. At higher populations, both long wavelength in phase patterns and short wavelength out-of-phase patterns are predicted by the analysis. Finally, at higher population densities, only out-of-phase patterning persists. (d) Spatial instabilities, their phase and spatial frequency predicted by the linear analysis in the ap, α1 parameter- space. We use for which the spatially homogeneous steady state is stable when ap, = 0 = α1. For weak competition (α1 > 2.5 × 10−6) an in-phase instability of low frequency (long wavelength) occurs. For sufficiently strong competition and desire for spatial separation, out-of-phase instability with higher spatial frequency is dominant. For α1 > 2.5 × 10−5, there is so much competition for space that services do not have the population nearby to overcome this competition and they die out completely, leaving a stable solution again. The black ‘x’ marks the point in parameter space used for the simulations in (a,b) showing how secondary patterning persists even into regions not predicted by the linear stability analysis. and ap > 0 (appendix C.2). These are necessary but not sufficient conditions. The Jacobian not only enables us to see whether an instability emerges but we can also see the phase of this perturbation; whether we expect p and s to grow in the same places or to separate. We do this by looking at the eigenvector corresponding to the unstable eigenvalue. Figure 5c shows the change in the dispersion relation as we increase the initial population. At p ¼ 5000, the homo- geneous state is given as s0 = 0. At p ¼ 12 000, both in- and out-of-phase patterning are predicted. As we increase the population density to no pattern is unstable. Lastly, as the population density further increases, the competition forces out of phase patterning again. Moreover, we see that in phase patterning occurs at similar frequencies to before, with a wavelength of around 50 km. Out-of-phase patterning occurs at a shorter wavelength of around 5 km, which is a frequency of 1.25. 6. Secondary patterning when services compete for space and residents avoid high service d i The Jacobian is given by The Jacobian is given by Jð p0; s0; kÞ ¼ Ds0ð1  s0Þð1  ^w p2ðkÞÞ Dp0ð1  ^w p2ðkÞÞ ðð1  s0Þ^w p1ðkÞ  s0Þ ð f þ gs0Þðs0ð p0Þ^wsðkÞ  a1Þ ð f þ gs0Þ 2 64 3 75 ds dt ðx, tÞ ¼ ðHðsðPÞ  ðs þ a1pÞÞ f þ gsÞ  (sðPÞ  ðs þ a1pÞ): ð6:2Þ ð6:4Þ (a) (b) (c) (d) –100 –50 0 population density service density distance (km) distance (km) service density population density 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 0 2 4 6 8 ×104 ×104 0 0.5 1 0 2 4 6 8 0 0.5 1 0 0.5 1.0 1.5 spatial frequency, k (km–1) ap, length scale for popn-service separation a1, popn competition for service space growth rate (real part of leading eigenvalue) 2.0 2.5 3.0 –0.5 –0.4 –0.3 –0.2 –0.1 0 0.1 0 1 2 3 4 5 6 0 0.5 1.0 1.5 2.0 2.5 ×10–5 in-phase only in-phase dominant out-of-phase dominant kmax (km–1) 0 1.1 average population density p = 5000 p = 12 000 p = 25 000 p = 17 000 p = 30 000 in-phase pattern out-of-phase pattern – – – – – Figure 5. Out-of-phase patterning for the model with competition. (a,b) Example simulations showing how in-phase and out-of-phase patterning are possible. Both have the same parameters and mean population p ¼ 16 000, with α1 = 1.3 × 10−5. Initial conditions can be seen in figure 11. (c) Dispersion relations for different values of the average population, p. At low populations, there is not sufficient service potential to overcome competition for space so no instability can persist. At higher populations, both long wavelength in phase patterns and short wavelength out-of-phase patterns are predicted by the analysis. Finally, at higher population densities, only out-of-phase patterning persists. (d) Spatial instabilities, their phase and spatial frequency predicted by the linear analysis in the ap, α1 parameter- space. We use for which the spatially homogeneous steady state is stable when ap, = 0 = α1. For weak competition (α1 > 2.5 × 10−6) an in-phase instability of low frequency (long wavelength) occurs. For sufficiently strong competition and desire for spatial separation, out-of-phase instability with higher spatial frequency is dominant. 6. Secondary patterning when services compete for space and residents avoid high service d i (a) –100 –50 0 population density service density distance (km) 50 –100 –50 0 50 0 2 4 6 8 ×104 0 0.5 1 (a) (b) –100 –50 0 population density service density distance (km) distance (km) service density population density 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 0 2 4 6 8 ×104 ×104 0 0.5 1 0 2 4 6 8 0 0.5 1 (b) distance (km) service density population density –100 –50 0 50 –100 –50 0 50 ×104 0 2 4 6 8 0 0.5 1 (a) (b) (c) (d) –100 –50 0 population density service density distance (km) distance (km) service density population density 50 –100 –50 0 50 –100 –50 0 50 –100 –50 0 50 0 2 4 6 8 ×104 ×104 0 0.5 1 0 2 4 6 8 0 0.5 1 0 0.5 1.0 1.5 spatial frequency, k (km–1) ap, length scale for popn-service separation a1, popn competition for service space growth rate (real part of leading eigenvalue) 2.0 2.5 3.0 –0.5 –0.4 –0.3 –0.2 –0.1 0 0.1 0 1 2 3 4 5 6 0 0.5 1.0 1.5 2.0 2.5 ×10–5 in-phase only in-phase dominant out-of-phase dominant kmax (km–1) 0 1.1 average population density p = 5000 p = 12 000 p = 25 000 p = 17 000 p = 30 000 in-phase pattern out-of-phase pattern – – – – – 10 population density (c) (d) 0 0.5 1.0 1.5 spatial frequency, k (km–1) ap, length scale for popn- a1, popn competition for service space growth rate (real part of leading eigenvalue) 2.0 2.5 3.0 –0.5 –0.4 –0.3 –0.2 –0.1 0 0.1 0 1 2 3 0 0.5 1.0 1.5 2.0 2.5 ×10–5 kmax (km–1) 0 1.1 average population density p = 5000 p = 12 000 p = 25 000 p = 17 000 p = 30 000 in-phase pattern out-of-phase pattern – – – – – (c) 0 0.5 1.0 1.5 spatial frequency, k (km–1) growth rate (real part of leading eigenvalue) 2.0 2.5 3.0 –0.5 –0.4 –0.3 –0.2 –0.1 0 0.1 average population density p = 5000 p = 12 000 p = 25 000 p = 17 000 p = 30 000 in-phase pattern out-of-phase pattern – – – – – (c) ap, length scale for popn-service separation Figure 5. Out-of-phase patterning for the model with competition. 6. Secondary patterning when services compete for space and residents avoid high service d i For α1 > 2.5 × 10−5, there is so much competition for space that services do not have the population nearby to overcome this competition and they die out completely, leaving a stable solution again. The black ‘x’ marks the point in parameter space used for the simulations in (a,b) showing how secondary patterning persists even into regions not predicted by the linear stability analysis. 6. Secondary patterning when services compete for space and residents avoid high service d i In order for out-of-phase patterns to be predicted by the linear analysis, we must have α1 > 0 Figure 5d maps an example of where in the α1, ap par- ameter regime in- and out-of-phase patterning is predicted. The homogeneous steady state is given by s0 = σ( p0) −α1p0. Therefore, as we increase α1 so the steady state for s0 will decrease. If the original homogeneous steady state is stable, as in figure 5, introducing some competition may induce in-phase patterning. Increasing ap, the ideal length people wish to be from services, can induce out-of-phase patterning, as long as there is sufficient competition to drive it. For very large α1, competition for space means that services do not have the population nearby to overcome this competition and they die out completely, leaving a stable steady state again. The out-of-phase patterning seen in figure 5b is not pre- dicted by the linear stability analysis of the homogeneous (a) (c) (b) (–) logistic growth (–) competition (–) competition (+) carrying capacity (–) movement (+) attraction (–) logistic growth Key: non-local interaction local interaction services, s population, p 0 0.5 1.0 1.5 2.0 2.5 3.0 spatial frequency, k (km–1) –0.06 –0.04 –0.02 0 0.02 0.04 dispersion relations for 1D and 2D cases growth rate (real part of leading eigenvalue) –40 –20 0 20 40 –40 –20 0 20 40 –40 –20 0 20 40 –40 –20 0 20 40 –40 –20 0 20 40 –40 distance (km) –20 0 20 40 –40 distance (km) distance (km) –40 –20 0 20 40 distance (km) –40 –20 0 20 40 distance (km) –40 –20 0 20 40 distance (km) –20 0 20 40 –40 –20 0 20 40 –40 –20 0 20 40 –40 –20 0 20 40 time = 0 years time = 200 years time = 500 years time = 1000 years ×104 –40 –20 0 20 40 –40 –20 0 20 40 –40 –20 0 20 40 0 0.5 1.0 1.5 2.0 0 0.05 0.10 0.15 service density, s population density, p 1D 2D out-of-phase pattern in-phase pattern Figure 6. (a) Schematic diagram of the full model from §7 explaining the key interactions. This encompasses equations (6.2) and (7.1). (b) Dispersion relations corresponding to the one-dimensional and two-dimensional cases for the default parameter set (tables 1, 2 & 3), also corresponding to the simulation in (c). 6. Secondary patterning when services compete for space and residents avoid high service d i (a) Schematic diagram of the full model from §7 explaining the key interactions. This encompasses equations (6.2) and (7.1). (b) Dispersion relations corresponding to the one-dimensional and two-dimensional cases for the default parameter set (tables 1, 2 & 3), also corresponding to the simulation in (c). This shows that both in- and out-of-phase patterning can still be predicted when both the population and services grow and compete for space. (c) Simulation of the growth and secondary pattern formation of cities. Initial conditions are p0(x, y) = 200 on 10% of the domain. We see that, firstly, population grows everywhere and as it does, distinct cities appear. Then secondary structure emerges within the cities as population separates from services. space from services. This changes equation (4.4) to be steady state for this average population yet it can persist across the parameter space. In this particular case, such pat- terning is secondary, forming after an initial city has grown and developed. dp dt ðx, tÞ ¼ D ð ½AðxÞpðyÞ  AðyÞpðxÞwp2ðx  yÞ dy þ rp 1  p þ a2s c   : ð7:1Þ ð7:1Þ In summary, this model produces both in- and out- of-phase patterns of different spatial lengths; the new out-of-phase patterning is of shorter wavelength. Within a city context, the desire for co-location agglomerates people into cities and competition for space creates divisions in land use. A schematic of the full model can be seen in figure 6a and the new parameter values in table 3 with explanations in appendix E. Similarly to the previous case, in- and out-of-phase pat- terning are possible, depending upon the value for the carrying capacity c. This can be seen in dispersion relations as we vary the carrying capacity in figure 10 and in the example in figure 6. The homogeneous steady state from dp/dt is now dependent upon the carrying capacity c. The steady state is now given by the solution to 6. Secondary patterning when services compete for space and residents avoid high service d i This shows that both in- and out-of-phase patterning can still be predicted when both the population and services grow and compete for space. (c) Simulation of the growth and secondary pattern formation of cities. Initial conditions are p0(x, y) = 200 on 10% of the domain. We see that, firstly, population grows everywhere and as it does, distinct cities appear. Then secondary structure emerges within the cities as population separates from services. 6. Secondary patterning when services compete for space and residents avoid high service d i (b) 0 0.5 1.0 1.5 2.0 2.5 3.0 spatial frequency, k (km–1) –0.06 –0.04 –0.02 0 0.02 0.04 dispersion relations for 1D and 2D cases growth rate (real part of leading eigenvalue) 1D 2D out-of-phase pattern in-phase pattern (a) (a) (b) (–) logistic growth (–) competition (–) competition (+) carrying capacity (–) movement (+) attraction (–) logistic growth Key: non-local interaction local interaction services, s population, p 0 0.5 1.0 1.5 2.0 2.5 3.0 spatial frequency, k (km–1) –0.06 –0.04 –0.02 0 0.02 0.04 dispersion relations for 1D and 2D cases growth rate (real part of leading eigenvalue) 1D 2D out-of-phase pattern in-phase pattern (a) (b) dispersion relations for 1D and 2D cases (–) logistic growth (–) competition (–) competition (+) carrying capacity (–) movement (+) attraction (–) logistic growth Key: non-local interaction local interaction services, s population, p (–) logistic growth (c) –40 –20 0 20 40 –40 –20 0 20 40 –40 –20 0 20 40 –40 –20 0 20 40 –40 distance (km) –20 0 20 40 time = 0 years time = 200 years time = 500 years time = 1000 years ×104 –40 –20 0 20 40 –40 –20 0 20 40 –40 –20 0 20 40 0 0.5 1.0 1.5 2.0 population density, p (c) –40 –20 0 20 40 –40 –20 0 20 40 –40 distance (km) –20 0 20 40 time = 0 years time = 200 years –40 –20 0 20 40 –4 –2 2 4 population d 40 –40 –20 0 20 40 –40 –20 0 20 40 –40 –20 0 20 40 s time = 200 years time = 500 years time = 1000 years –40 –20 0 20 40 –40 –20 0 20 40 –40 –20 0 20 40 population density, p population density, p (c) 0 –40 –20 0 20 40 –40 –20 0 20 40 s time = 500 years time = 1000 years ×104 –40 –20 0 20 40 –40 –20 0 20 40 0 0.5 1.0 1.5 2.0 ulation density, p –40 –20 0 20 40 distance (km) –40 –20 0 20 40 distance (km) –40 –20 0 20 40 –40 –20 0 20 40 service density, s service density, s –40 –20 0 20 40 –40 distance (km) distance (km) –40 –20 0 20 40 distance (km) –20 0 20 40 –40 –20 0 20 40 service –40 –20 0 20 40 distance (km) –40 –20 0 20 40 density, s –40 –20 0 20 40 distance (km) –40 –20 0 20 40 0 0.05 0.10 0.15 Downloaded from https://royalsocietypublish Figure 6. 7. Including population growth and competition shows cities emerging before secondary patterning appears Lastly, we include population growth in the model via logis- tic growth up to some carrying capacity with competition for ð7:2Þ p0 þ a2s0 ¼ c, s0 ¼ sðp0Þ  a1p0: ð7:2Þ ble 3. Supplement to tables 1 and 2 showing the default values for the new parameters in equation (7.1) Table 3. Supplement to tables 1 and 2 showing the default values for the new parameters in equation (7.1) 12 royalsocietypublishing.org/journal/rsif J. R. Soc. Interface 19: 20220176 parameter definition default value justification r intrinsic population growth rate 0:05 yr1 see appendix E c carrying capacity for population density 12 000 pe km2 c will define p, therefore we consider a similar range α2 competition of services to population density 100 000 pe km2 at steady state, p + α2s = c. If p ¼ 10 000 pe km2, and s = 0.05, then a2 ¼ 100 000 pe km2 The hierarchy of integro-differential equation models developed here focuses on spatial kernels to capture the dis- tribution of non-local dependencies. This model shows that the preference for population location in proximity to services can either lead to a completely mixed homogeneous state or drive the emergence of urban centres, seen in a spatial pat- tern. Numerical continuation and linear stability analysis of the steady states of this model shows how different length scales emerge, depending upon the initial conditions and parameters (figure 4). In phase spatial instabilities are shown to be destabilizing only if the perturbation is of a suf- ficiently long spatial scale and only if a change in population density produces a sufficient change in service density. One observation from this model is that many steady states are metastable; over long time periods, we would see transitions at the merging of city centres as cities agglomerate. We note that it is possible to keep the previous steady state {p0, s0} unchanged by choosing c as f J. R. Soc. 7. Including population growth and competition shows cities emerging before secondary patterning appears Interface 19: 20220176 c ¼ p0 þ a2s0: ð7:3Þ ð7:3Þ The Jacobian used to produce these dispersion relations is as follows: nloaded from https://royalsocietypublishing.org/ on 05 May 2022 ://royalsocietypublishing.org/ on 05 May 2022 Downloaded from https://royalsocietypublishing.org/ on 05 May 2022 Jð p0; s0; kÞ 2 Jð p0; s0; kÞ ¼ Dp0ð1  ^wp2ðkÞÞ Ds0ð1  s0Þð1  ^w p2ðkÞÞ  rp0 c ðð1  s0Þ^w p1ðkÞ  s0Þ  ra2p0 c ð f þ gs0Þðs0ð p0Þ^wsðkÞ  a1Þ ð f þ gs0Þ 2 6666664 3 7777775 ð7:4Þ Downloaded from https://royalsocietypublishing.or ð7:4Þ The effect of logistic growth is generally stabilizing for long wavelength perturbations. In particular, homogeneous per- turbations would return to the steady state. However, the competition parameter α2 will tend to be destabilizing for higher spatial frequencies, assuming that population and ser- vices both compete sufficiently for space (appendix C.3). Within cities, we also see patterning emerge around local services as long scale co-location and short scale separation of population and service provision occurs. In the model, this is driven by competition for space and desire by people to be near, but not too near, to the services they need to support them (figure 5). Figure 6c shows an example simulation of the full model in two dimensions, demonstrating growth of cities and sec- ondary, out-of-phase, patterning that gives separation of population and services. Population initially grows but is not sufficient to drive urbanization. Then, after a number of years, cities form as there is sufficient population to drive the demand for services and colocation. Continuing time for- ward further shows that, within these cities there are distinct areas of service provision, surrounded by population. This model more realistically captures the long-term growth dynamics of population into urban areas. Length scales within the model are typical of those seen in the data for the UK. Differences in parameters such as house moves and preferred travel distances may explain different length scales between the UK and the USA. In the USA, people might tend to move greater distances, both to move house and to travel to their desired services, which gives rise to sprawling metropolises. Conversely, the rapidly urbanizing cities of China and Brazil may be driven by people moving long distances to be as close as possible to services, generating high-density distinct megacities. Our modelling approach would give valuable insight into the different city formations around the world. 8.1. Conclusion Interface 19: 20220176 13 Figure 7. Increasing typical travel distances over time leads to exaggerated agglomeration. We vary b p1, b p2 and βs as in (F1). The mean population density is p ¼ 10 000 pe km2. Initially (t ≈30), the pattern that emerges from random perturbations to the spatially homogeneous steady state has a wavelength of approximately 16 km. As time continues, the pattern coarsens and larger agglomerations form with a wavelength of about 100 km. Further details of the parameter variation can be found in appendix F. from https://royalsocietypublishing.org/ on 05 May 2022 Downloaded from https://royalsocietypublishing.org/ on 05 May 2022 one example of dynamically changing length scale par- ameters in figure 7 to highlight the potential of our modelling approach. supported by the Leverhulme Trust research programme ‘Sustaining urban habitats: an interdisciplinary approach’. T.D.W. acknowledges funding from the University of Nottingham Future Food Beacon of Excellence. Thirdly, we have assumed that people (and services) are motivated solely by coexistence preferences. In reality, people’s desires will also be affected by multiple competing interests such as employment opportunities, housing stock and house prices, transport and more—all of which require attention. This would be further confounded by the disaggre- gation of people according to factors such as income or ethnicity, or disaggregation of service types into retail, indus- try, etc. It is not easy to determine the relative importance of such influences or disentangle the effects of each. Our focus on colocation preferences of people and services has enabled us to elicit understanding regarding the implications of those preferences for patterning and urban length scales. Acknowledgements. The authorsthank three anonymous reviewers for their helpful and constructive suggestions in reviewing the manuscript. Downloaded from https://royalsocietypublishin Appendix A. Length scales in the USA Figure 8 shows the results from length scale analysis of popu- lation density data from the north east USA, from the 2010 Census at census tract level [40] similarly to §3. Autocorrela- tion on a region of Indiana, Ohio and Kentucky demonstrates a spatial length scale of 200 km. We also take the Fourier transform of a slice through key cities on the East coast: Washington, Philadelphia, New York and Boston, which gives a similar 200 km length scale. The USA seems to show a longer characteristic length scale than the UK. Downloaded from https://roy Despite these limitations, our approach is intuitive and mathematically rigorous. By developing an aggregated form of model, we have sidestepped the myriad of uncertainties involved in bottom-up modelling and minimized the varia- bility. We hope that this exploration can be a springboard for future developments to accommodate these complicating factors which could deepen our understanding of the spatial development of populations. Appendix B. Numerical methods For timestepping and numerical continuation, we use a code structure from Avitabile [39]. We use a pseudospectral colloca- tion method to compute convolutional integral operators. Hence, we expect spectral accuracy for the spatial discretization (albeit wehavenotusedde-aliasing).This requirestheuseofper- iodic boundary conditions; implying that the region considered is similar to its neighbouring regions. Data accessibility. All data are from publicly available and cited sources. All code is publicly available at: https://doi.org/10.5281/zenodo. 5034211. Authors’ contributions. T.D.W.: conceptualization, data curation, formal analysis, investigation, methodology, software, writing—original draft, writing—review and editing; D.A.: formal analysis, method- ology, resources, software, supervision, writing—review and editing; P.-O.S.: supervision, writing—review and editing; D.R.: funding acquisition, project administration, supervision, writing— review and editing; M.R.O.: conceptualization, formal analysis, fund- ing acquisition, investigation, methodology, project administration, resources, software, supervision, writing—review and editing. To converge on and continue steady-states, we perform Newton-GMRES iterations with tolerance 0.001. For the time-stepper, we use the same spatial grid and discretization method as the steady-state calculations, and we employ Matlab’s in-built ode113 routine, with default tolerances. 8.1. Conclusion The emergence of spatial structure in human populations has received relatively little attention when compared with the quantification of urban patterns. Much focus has been on measuring structure rather than understanding or predicting where those structures come from. Inspired by typical length scales that are apparent in population density data between cities, here we have shown that a simple set of plausible local and spatial interactions can explain the emergence of cities via reinforced aggregation. While conceptually simple in comparison with computer modelling techniques such as cellular automata and agent-based models, these models benefit from deeper explanatory power; offering the potential not just to describe what we currently see in cities but also to explain how such dynamics emerge. Our parsimonious approach has several limitations. Firstly, by using an aggregated differential equation methodology, we have gained mathematical tractability but lost the effects of population heterogeneity. As explained in the literature review, we believe that this approach provides a useful coun- terpoint to the increasingly popular bottom up agent-based methodologies. Secondly, we have considered parameters that are static over time. Technological advances and societal changes will doubtless affect the functions and kernels that capture behav- iour. This simplification enables us to provide mathematical rigour to our conclusions that would not be possible with further complicating assumptions. Such work is beyond the scope of this paper, but we motivate the discussion with population density service density 2.0 250 200 150 100 50 0 250 0.6 0.5 0.4 0.3 0.2 0.1 200 150 100 50 0 time (years) ×104 1.5 1.0 0.5 100 0 –100 distance (km) 100 0 –100 distance (km) Figure 7. Increasing typical travel distances over time leads to exaggerated agglomeration. We vary b p1, b p2 and βs as in (F1). The mean population density is p ¼ 10 000 pe km2. Initially (t ≈30), the pattern that emerges from random perturbations to the spatially homogeneous steady state has a wavelength of approximately 16 km. As time continues, the pattern coarsens and larger agglomerations form with a wavelength of about 100 km. Further details of the parameter variation can be found in appendix F. service density 250 0.6 0.5 0.4 0.3 0.2 0.1 200 150 100 50 0 100 0 –100 distance (km) population density 2.0 250 200 150 100 50 0 time (years) ×104 1.5 1.0 0.5 100 0 –100 distance (km) royalsocietypublishing.org/journal/rsif J. R. Soc. C.1. Linearization of the model without competition or population growth We define Fðp, sÞ ¼ _pðx, tÞ _sðx, tÞ   : ðC 1Þ kernel with parameter ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi b 2 p1 þ b 2 p2 q . We have that for any kernel w, kernel with parameter ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi b 2 p1 þ b 2 p2 q . We have that for any kernel w, kernel with parameter ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi b 2 p1 þ b 2 p2 q . We have that for any kernel w, ðC 1Þ w  ~p ¼ w  pðtÞ eikx ¼ pðtÞ ð1 1 eikðxyÞwðyÞdy ¼ pðtÞ eikx ð1 1 eikywðyÞ dy ¼ ^wðkÞ pðtÞ eikx: ðC 5Þ Then we calculate Fðp0 þ ~p, s0 þ ~sÞ  Fðp0, s0Þ where {p0, s0} are the current state and f~p, ~sg are the perturbations from this state of order ϵ. Using a Taylor expansion for σ, we get ðC 5Þ Fðp0þ~p,s0þ~sÞFðp0,s0Þ e Similarly, we have w ~s ¼ ^wðkÞsðtÞ eikx. Using this, we will calculate the Jacobian of the temporal change in coefficients p and s close to the steady state by substituting ~p ¼ p eikx and ~s ¼ s eikx into (C 2). At the homogeneous steady state s0 = σ( p0), w ∗p0 = p0 and w ∗s0 = s0. ¼ D½A0ðwp2 ~pÞþ ~Aðwp2 p0Þ~pðwp2 A0Þp0ðwp2  ~AÞÞ ðf þgs0Þð~ps0ðp0Þ~sÞþg~sðsðp0Þs0Þ ! , ð Þ Factoring out eikx and writing in matrix form, we get where where _p _s ! _p _s ! ¼ Ds0ð1  s0Þð1  ^w p2ðkÞÞ Dp0ð1  ^wp2ðkÞÞ ðð1  s0Þ^w p1ðkÞ  s0Þ ð f þ gs0Þs0ð p0Þ^wsðkÞ ð f þ gs0Þ 2 664 3 775 p s   : ðC 6Þ A ¼ A0 þ ~A ¼ ðw p1 s0Þ  ð1  s0Þ þ (ðw p1 ~sÞ  ð1  s0Þ  ðw p1 s0Þ  ~s): ðC 3Þ ! ¼ Ds0ð1  s0Þð1  ^w p2ðkÞÞ Dp0ð1  ^wp2ðkÞÞ ðð1  s0Þ^w p1ðkÞ  s0Þ ð f þ gs0Þs0ð p0Þ^wsðkÞ ð f þ gs0Þ 2 664 3 775 p s   : ðC 6Þ ðC 3Þ In order to look at different spatial frequencies, we con- sider perturbations that are sinusoidal by considering ðC 6Þ f~pðx, tÞ, ~sðx, tÞg ¼ fpðtÞ eikx, sðtÞ eikxg: ðC 4Þ ðC 4Þ This Jacobian can be validated against the simulation to show it correctly approximates the behaviour of the system close to the steady state. C.1. Linearization of the model without competition or population growth Conflict of interest declaration. We declare we have no competing interests. Funding. All authors were supported by funding for the PhD of T.D.W. from the Leverhulme Trust Doctoral Scholarships programme, Modelling and Analytics for a Sustainable Society (MASS, DS-2014- 024) at the University of Nottingham. P.-O.S. and D.R. were also Here, we show the linearization of _p, _s from equations (4.4) and (4.6) for use in the Numerical continuation algorithm population density people per hectare 0–68 68–369 369–932 932–1713 1713–3851 3851–196 149 0 200 400 600 km 0 100 200 300 400 500 displacement (km) –0.1 0 0.1 0.2 Moran’s I autocorrelation: Indiana/Kentucky/Ohio 100 200 300 400 500 wavelength (km) 0 0.5 1.0 1.5 2.0 2.5 amplitude Fourier transform: north east USA ¥105 (a) (b) (c) Figure 8. (a) Map of the population density of north east USA showing the areas analysed. Background mapping © Open street map contributors. (b) Correlogram or Indiana/Kentucky/Ohio region showing length scale peaks at 200 km and 400 km. (c) Fourier transform of the line from Washington to Boston, giving a corre- ponding wavelength of about 200 km. population density people per hectare 0–68 68–369 369–932 932–1713 1713–3851 3851–196 149 0 200 400 600 km (a) 100 200 300 400 500 wavelength (km) 0 0.5 1.0 1.5 2.0 2.5 amplitude Fourier transform: north east USA ¥105 (c) 0 100 200 300 400 500 displacement (km) –0.1 0 0.1 0.2 Moran’s I autocorrelation: Indiana/Kentucky/Ohio (b) (c) autocorrelation: Indiana/Kentucky/Ohio Downloaded from https://royalsocietypublishing.org/ on 05 May 20 Figure 8. (a) Map of the population density of north east USA showing the areas analysed. Background mapping © Open street map contributors. (b) Correlogram for Indiana/Kentucky/Ohio region showing length scale peaks at 200 km and 400 km. (c) Fourier transform of the line from Washington to Boston, giving a corre- sponding wavelength of about 200 km. Downloaded from https://royalsocietypubli that: Fðw p12Þ ¼ Fðw p1ÞFðw p2Þ ¼ e2ðp2b2 p1 Þk2 e2ðp2b2 p2 Þk2 ¼ e2p2ðb2 p1 þb2 p2 Þk2. Thus w p12 is also a normalized Gaussian that: Fðw p12Þ ¼ Fðw p1ÞFðw p2Þ ¼ e2ðp2b2 p1 Þk2 e2ðp2b2 p2 Þk2 ¼ e2p2ðb2 p1 þb2 p2 Þk2. Thus w p12 is also a normalized Gaussian and then obtaining the Jacobian used in the linear stability analysis. We define and then obtaining the Jacobian used in the linear stability analysis. C.1. Linearization of the model without competition or population growth We will use the fact that the Fourier transform of a Gaussian kernel, as defined in (4.9), is ^wðkÞ ¼ e2ðp2b2Þk2. This is also Gaussian and ^wð0Þ ¼ 1 for any β. It has a maximum at k = 0 and 8k, 0  ^wðkÞ  1. Moreover, we define the kernel w p12 :¼ w p1  w p2. In the case that w p1 and w p2 are Gaussian, the convolution theorem gives C.2. Out-of-phase patterning requires α1 > 0 and ^w p1ðkÞ , 0 Here, we extend the linear analysis to the model with services competing for space with population (α1 > 0) and show that out of phase spatial instability is predicted only if α1 > 0 and ^w p1ðkÞ , 0. This condition on the popu- lation location preference kernel corresponds to the population preferring to move to locations near to but some preferred distance from services (ap > 0 in equation (6.1)). Downloaded from https://royalsocietypu Now assume that s0(1 −s0)/( p0σ0( p0)) + s0 < (1 −s0). Then F(0) < G(0). However, limk→∞F(k) = s0(1 −s0)/( p0σ0( p0)) > 0 and limk→∞G(k) = 0. Therefore, there must be at least one crossing point and hence a solution to det(J ) = 0. Conversely, if s0(1 −s0)/( p0σ0( p0)) + s0 > 1 −s0, we must look at two cases. Including competition, the linearized dynamics close to the spatially homogeneous steady state is given by Case 1: s0 > (1 −s0). For all k > 0, _p _s ! ¼ Ds0ð1  s0Þð1  ^w p2ðkÞÞ Dp0ð1  ^wp2ðkÞÞ ðð1  s0Þ^w p1ðkÞ  s0Þ ð f þ gs0Þðs0ð p0Þ^wsðkÞ  a1Þ ð f þ gs0Þ 2 664 3 775 p s   : ðC 8Þ FðkÞ  s0 ^ws . ð1  s0Þ^ws . ð1  s0Þ^ws ^w p1 ¼ GðkÞ: _p _s ! ¼ Ds0ð1  s0Þð1  ^w p2ðkÞÞ Dp0ð1  ^wp2ðkÞÞ ðð1  s0Þ^w p1ðkÞ  s0Þ ð f þ gs0Þðs0ð p0Þ^wsðkÞ  a1Þ ð f þ gs0Þ 2 664 3 775 p s   : ðC 8Þ Therefore, FðkÞ = GðkÞ 8 k . 0. Therefore, FðkÞ = GðkÞ 8 k . 0. ! ¼ Ds0ð1  s0Þð1  ^w p2ðkÞÞ Dp0ð1  ^wp2ðkÞÞ ðð1  s0Þ^w p1ðkÞ  s0Þ ð f þ gs0Þðs0ð p0Þ^wsðkÞ  a1Þ ð f þ gs0Þ 2 664 3 775 p s   : ðC 8Þ ð Þ ð Þ Case 2: s0 ≤(1 −s0). We have that F(0) = s0(1 −s0)/ ( p0σ0( p0)) + s0 > 1 −s0 = G(0). F0ðkÞ ¼ s0 d^ws dk  ð1  s0Þ d^ws dk  ð1  s0Þ dð^ws ^w p1Þ dk ¼ G0ðkÞ: ðC 8Þ So we have that F0(k) > G0(k) and F(0) > G(0). Therefore, these two functions are never equal and hence there is no sol- ution to F(k) = G(k). C.1.1. Conditions for spatial instability Using the Jacobian from equation (5.5), also shown above in equation (C 6), we wish to prove the following: processes (reaction and diffusion). However, this result shows that, in our model, instabilities occur only if the reaction of services to a change in population is sufficient. It is independent of the relative rates (figure 9). This indepen- dence is largely due to the conservation of population (in the first two model variations) which means that there is a zero eigenvalue at frequency k=0 and instabilities occur in a window [0, kc] rather than [k1, k2] as in a reaction–diffusion equation. For Gaussian kernels, there are unstable frequencies if and only if s0(1 −s0)/(p0σ0(p0)) + s0 < (1 −s0). If this holds, then instability occurs in a window (0, kc) for some critical frequency kc. 15 royalsocietypublishing.org/journal/rsif J. R. Soc. Interface 19: 20220176 If the system is stable, then both eigenvalues of J will have negative real part which is the case when trðJÞ and detðJÞ . 0. We have that for the Fourier transform of a Gaussian kernel, ^w  1. Moreover, s0 ≤1 and so tr(J ) < 0 for all frequencies k. Therefore, we only need to look at the sign of detðJÞ which can be rearranged as C.1.2. Dispersion relations for other parameters Figure 4a shows dispersion relations for the default set of par- ameters as the total population p varies. Here, we show dispersion relations for the other parameters in the model illustrating how changing them modifies the predicted emer- gent pattern. detðJðkÞÞ ¼ Dð1  ^w p2Þðf þ gs0Þp0s0ðp0Þ  s0ð1  s0Þ p0s0ðp0Þ þ s0 ^ws  ð1  s0Þ^ws ^w p1   : ðC 7Þ ðC 7Þ We note that det(J(0)) = 0 and limk→∞det(J(k)) = D(f + gs0) s0(1 −s0) > 0. Therefore, we look for a second zero of det(J(k)). If a second solution to det(J ) = 0 exists at k = kc and no third sol- ution exists, then det(J ) < 0 for k ∈(0, kc] and det(J ) > 0 for k ∈(kc, ∞); that is, the steady state is unstable to perturbations with wavelengths k ∈[0, kc). This gives some idea of the impact that uncertainty about parameter values may have on model predictions. Overall, pattern formation is robust and predicted across a wide range of parameters. On the other hand, the specific wavelength of predicted patterns does vary with certain key parameters as expected; parameters controlling length scales of movement (b p1, b p2, bs) and feedback (μ) signifi- cantly modulate wavelengths, whereas those affecting rates of movement (D) and service growth (f, g) have a much weaker effect. See figure 9. Downloaded from https://royalsocietypublishing.org/ on 05 May 2022 m https://royalsocietypublishing.org/ on 05 May 2022 In order to analyse det(J ), we first define FðkÞ ¼ s0ð1  s0Þ=ð p0s0ðp0ÞÞ þ s0 ^wsðkÞ, GðkÞ ¼ ð1  s0Þ^w sðkÞ^wp1ðkÞ. For k > 0, det(J(k)) = 0 iff F(k) −G(k) = 0. We claim that a non- zero solution to F(k) = G(k) exists if and only if s0(1 −s0)/(p0σ0( p0- )) + s0 < 1 −s0 and that if it exists, this solution is unique. Downloaded from https://royalsocietypublishing.org/ on 05 We will use the fact that ^wsðkÞ^w p1ðkÞ ¼ ep2k2ð1=bsþ1=b p1 Þ. From the shape of Gaussian functions, ^ws ^w p1 , ^ws 8 k . 0. Secondly, ^ws ^w p1 is steeper than ^ws. That is that ðd=dkÞð^ws ^w p1Þ , ðd=dkÞ^ws , 0. C.2. Out-of-phase patterning requires α1 > 0 and ^w p1ðkÞ , 0 ðs0= p0Þð1  sðp0ÞÞ We note that in a typical reaction–diffusion equation, Turing instabilities occur due to the interplay of the two –0.05 0 0.2 0.4 spatial frequency, k (km–1) 0.6 0 0.2 0.4 spatial frequency, k (km–1) 0.6 0 0.05 0.10 0.15 0.20 0.25 dispersion relation: population’s desired proximity to services (a) (b) (c) (d) (e) (f) growth rate (real part of leading eigenvalue) –0.05 0 0.05 0.10 0.15 0.20 0.25 growth rate (real part of leading eigenvalue) dispersion relation: service catchment length scale –0.05 0 0.2 0.4 spatial frequency, k (km–1) 0.6 0 0.2 0.4 spatial frequency, k (km–1) 0.6 0 0.2 0.4 spatial frequency, k (km–1) 0.6 0 0.2 0.4 spatial frequency, k (km–1) 0.6 0 0.05 0.10 0.15 0.20 0.25 dispersion relation: average move distance dispersion relation: service reaction to population change growth rate (real part of leading eigenvalue) –0.05 0 0.05 0.10 0.15 0.20 0.25 growth rate (real part of leading eigenvalue) –0.05 0 0.05 0.10 0.15 0.20 0.25 growth rate (real part of leading eigenvalue) –0.05 0 0.05 0.10 0.15 0.20 0.25 growth rate (real part of leading eigenvalue) (g) 0 0.05 0.10 0.15 0.20 0.25 growth rate al part of leading eigenvalue) dispersion relation: rate of services innovators dispersion relation: rate of people moving home dispersion relation: rate of service followers bp1 = 0.5 bp2 = 2 m = 1 m = 2 m = 3 m = 4 m = 5 bp2 = 5 bp2 = 10 bp2 = 20 bp2 = 50 D = 1 D = 2 D = 10 D = 20 f = 0.005 f = 0.05 f = 0.1 f = 1 g = 0.1 g = 1 g = 2 g = 10 g = 20 bp1 = 1 bp1 = 2 bs = 2 bs = 5 bs = 10 bp1 = 5 –0.05 0 0.2 0.4 spatial frequency, k (km–1) 0.6 0 0.05 0.10 0.15 0.20 0.25 dispersion relation: population’s desired proximity to services (a) growth rate (real part of leading eigenvalue) bp1 = 0.5 bp1 = 1 bp1 = 2 bp1 = 5 0 0.2 0.4 spatial frequency, k (km–1) 0.6 (b) –0.05 0 0.05 0.10 0.15 0.20 0.25 growth rate (real part of leading eigenvalue) dispersion relation: service catchment length scale bs = 2 bs = 5 bs = 10 (b) 16 (a) –0.05 0 0.2 0.4 spatial frequency, k (km–1) 0.6 0 0.2 0.4 spatial frequency, k (km–1) 0.6 0 (c) (d) (e) (f) (real p –0.05 0 (real p –0.05 0 0.2 0.4 spatial frequency, k (km–1) 0.6 0 0.2 0.4 spatial frequency, k (km–1) 0.6 0 0.2 0.4 spatial frequency, k (km–1) 0.6 0 0.2 0.4 spatial frequency, k (km–1) 0.6 0 0.2 0.4 spatial frequency, k (km–1) 0.6 0 0.05 0.10 0.15 0.20 0.25 dispersion relation: average move distance dispersion relation: service reaction to population change growth rate (real part of leading eigenvalue) –0.05 0 0.05 0.10 0.15 0.20 0.25 growth rate (real part of leading eigenvalue) –0.05 0 0.05 0.10 0.15 0.20 0.25 growth rate (real part of leading eigenvalue) –0.05 0 0.05 0.10 0.15 0.20 0.25 growth rate (real part of leading eigenvalue) (g) –0.05 0 0.05 0.10 0.15 0.20 0.25 growth rate (real part of leading eigenvalue) dispersion relation: rate of services innovators dispersion relation: rate of people moving home dispersion relation: rate of service followers bp2 = 2 m = 1 m = 2 m = 3 m = 4 m = 5 bp2 = 5 bp2 = 10 bp2 = 20 bp2 = 50 D = 1 D = 2 D = 10 D = 20 f = 0.005 f = 0.05 f = 0.1 f = 1 g = 0.1 g = 1 g = 2 g = 10 g = 20 Figure 9. C.2. Out-of-phase patterning requires α1 > 0 and ^w p1ðkÞ , 0 Thus a second solution to det(J ) = 0 exists if and only if s0(1 −s0)/( p0σ0( p0)) + s0 < 1 – s0. As previously, linear stability occurs when trðJðkÞÞ , 0 and detðJðkÞÞ . 0. For Gaussian ^w p2, the trace is negative for all k and therefore there are instabilities occurring for det(J(k)) < 0. Finally, we must show the solution is unique. Assume that there is a solution to F(k) = G(k). This implies that s0(1 −s0)/( p0σ0( p0)) + s0 < 1 −s0 and hence s0 < 1 −s0. Using case 2 from above, F0ðkÞ . G0ðkÞ 8 k . 0. As the derivatives are never equal, Rolle’s theorem shows that the solution must be unique in the range k > 0. detðJðkÞÞ ¼ Dð1  ^w p2ðkÞÞðf þ gs0Þ  (s0ð1  s0Þ  p0ðs0ðp0Þ^wsðkÞ  a1Þðð1  s0Þ^w p1ðkÞ  s0Þ) ðC 9Þ ðC 9Þ detðJÞ  0 , s0ð1  s0Þ  p0ðs0ðp0Þ^wsðkÞ  a1Þðð1  s0Þ^w p1ðkÞ  s0Þ ðC 10Þ , s0 p0 ð1  sðp0ÞÞ þ s0s0ðp0Þ^wsðkÞ  ð1  s0Þðs0ðp0Þ^wsðkÞ  a1Þ^w p1ðkÞ: ðC 11Þ Thus we have showed that det(J ) > 0 for sufficiently large k. Therefore, if there are no solutions to F(k) = G(k), then det(J ) > 0 for all k > 0. A solution can occur if and only if s0(1 −s0)/( p0σ0( p0)) + s0 < 1 −s0 and if it exists, this solution is unique We have 1 −σ( p0) > 0 and, for Gaussian ws, ^ws . 0. This means that the left-hand side is positive i.e. ðs0= p0Þð1  sðp0ÞÞ We have 1 −σ( p0) > 0 and, for Gaussian ws, ^ws . 0. This means that the left-hand side is positive i.e. C.2. Out-of-phase patterning requires α1 > 0 and ^w p1ðkÞ , 0 Dispersion relations for the growth rate of spatial perturbations to a spatially homogeneous steady state in the conservative model for population and services dynamics given in §4, for the indicated values of the parameters b p1, bs, b p2, m, D, f and g. For all length scales β, as they increase the length of pattern increases. Increasing b p1 and βs slows the rate of patterning whereas b p2 increases the speed of patterning. As shown in §5, small values of μ show stability to all frequencies. As μ increases, the instability emerges from the origin with long wavelengths (small k) and shifts to shorter wavelengths (larger k). The rates f, D and g will, as expected, increase the growth rate of perturbations, but do not make any noteworthy change to the wavelength of the fastest growing mode or to the window of unstable frequencies. C.2. Out-of-phase patterning requires α1 > 0 and ^w p1ðkÞ , 0 (c) –0.05 0 0.2 0.4 spatial frequency, k (km–1) 0.6 0 0.05 0.10 0.15 0.20 0.25 dispersion relation: average move distance growth rate (real part of leading eigenvalue) bp2 = 2 bp2 = 5 bp2 = 10 bp2 = 20 bp2 = 50 (d) 0 0.2 0.4 spatial frequency, k (km–1) 0.6 dispersion relation: service reaction to population change –0.05 0 0.05 0.10 0.15 0.20 0.25 growth rate (real part of leading eigenvalue) m = 1 m = 2 m = 3 m = 4 m = 5 (d) (c) (e) (f) p q y ( ) p q y ( ) 0 0.2 0.4 spatial frequency, k (km–1) 0.6 0 0.2 0.4 spatial frequency, k (km–1) 0.6 –0.05 0 0.05 0.10 0.15 0.20 0.25 growth rate (real part of leading eigenvalue) –0.05 0 0.05 0.10 0.15 0.20 0.25 growth rate (real part of leading eigenvalue) dispersion relation: rate of services innovators dispersion relation: rate of people moving home D = 1 D = 2 D = 10 D = 20 f = 0.005 f = 0.05 f = 0.1 f = 1 (e) 0 0.2 0.4 spatial frequency, k (km–1) 0.6 –0.05 0 0.05 0.10 0.15 0.20 0.25 growth rate (real part of leading eigenvalue) dispersion relation: rate of people moving home D = 1 D = 2 D = 10 D = 20 (f) 0 0.2 0.4 spatial frequency, k (km–1) 0.6 –0.05 0 0.05 0.10 0.15 0.20 0.25 growth rate (real part of leading eigenvalue) dispersion relation: rate of services innovators f = 0.005 f = 0.05 f = 0.1 f = 1 (f) 0 0.2 0.4 spatial frequency, k (km–1) 0.6 (g) –0.05 0 0.05 0.10 0.15 0.20 0.25 growth rate (real part of leading eigenvalue) dispersion relation: rate of service followers g = 0.1 g = 1 g = 2 g = 10 g = 20 (g) Figure 9. Dispersion relations for the growth rate of spatial perturbations to a spatially homogeneous steady state in the conservative model for population and services dynamics given in §4, for the indicated values of the parameters b p1, bs, b p2, m, D, f and g. For all length scales β, as they increase the length of pattern increases. Increasing b p1 and βs slows the rate of patterning whereas b p2 increases the speed of patterning. the stability matrix In this section, we show that logistic growth will tend to be stabilizing for smaller frequencies (longer wavelengths) but destabilizing for larger frequencies if there is sufficient com- petition. The Jacobian of the full model with competition and logistic growth from equation (7.4) is Jðp0; s0; kÞ Jðp0; s0; kÞ ¼ Ds0ð1  s0Þð1  ^wp2ðkÞÞ  rp0 c Dp0ð1  ^wp2ðkÞÞ: ðð1  s0Þ^wp1ðkÞ  s0Þ ra2p0 c ðf þ gs0Þðs0ðp0Þ^wsðkÞ  a1Þ ðf þ gs0Þ 2 6666664 3 7777775 ðC 13Þ C.2. Out-of-phase patterning requires α1 > 0 and ^w p1ðkÞ , 0 As shown in §5, small values of μ show stability to all frequencies. As μ increases, the instability emerges from the origin with long wavelengths (small k) and shifts to shorter wavelengths (larger k). The rates f, D and g will, as expected, increase the growth rate of perturbations, but do not make any noteworthy change to the wavelength of the fastest growing mode or to the window of unstable frequencies. –0.5 0 0.5 1.0 1.5 spatial frequency, k (km–1) 2.0 2.5 3.0 carrying capacity and average population density c = 5000; p0 = 5000 c = 13 426; p0 = 12 000 c = 37 389; p0 = 17 000 c = 73 317; p0 = 25 000 c = 81 578; p0 = 30 000 in-phase pattern out-of-phase pattern –0.4 –0.3 –0.2 growth rate (real part of leading eigenvalue) –0.1 0 0.1 Figure 10. Dispersion relations for the full model including logistic growth and competition for space. This figure is very similar in its trend to figure 5c. The most notable difference is that there is no longer a zero eigenvalue at k = 0 corresponding to conservation of mass. –0.5 0 0.5 1.0 1.5 spatial frequency, k (km–1) 2.0 2.5 3.0 carrying capacity and average population density c = 5000; p0 = 5000 c = 13 426; p0 = 12 000 c = 37 389; p0 = 17 000 c = 73 317; p0 = 25 000 c = 81 578; p0 = 30 000 in-phase pattern out-of-phase pattern –0.4 –0.3 –0.2 growth rate (real part of leading eigenvalue) –0.1 0 0.1 re 10. Dispersion relations for the full model including logistic growth and competition for space. This figure is very similar in its trend to figure 5c. The most –0.5 0 0.5 1.0 1.5 spatial frequency, k (km–1) 2.0 2.5 3.0 carrying capacity and average population density c = 5000; p0 = 5000 c = 13 426; p0 = 12 000 c = 37 389; p0 = 17 000 c = 73 317; p0 = 25 000 c = 81 578; p0 = 30 000 in-phase pattern out-of-phase pattern –0.4 –0.3 –0.2 growth rate (real part of leading eigenvalue) –0.1 0 0.1 royalsocietypublishing.org/journal/rsif J. R. Soc. Interface 19: 20220176 17 typublishing.org/journal/rsif J. R. Soc. Interface 19: 20220176 spatial frequency, k (km–1) ownloaded from https://royalsocietypublishing.org/ on 05 May 2022 Figure 10. C.2. Out-of-phase patterning requires α1 > 0 and ^w p1ðkÞ , 0 Dispersion relations for the full model including logistic growth and competition for space. This figure is very similar in its trend to figure 5c. The most notable difference is that there is no longer a zero eigenvalue at k = 0 corresponding to conservation of mass. þs0s0ðp0Þ^ws . 0. For instabilities to occur the right-hand side must be therefore also be positive. The factors ðs0ðp0Þ^ws  a1Þ and ^w p1 must at least have the same sign or else they will be negative and this condition will not hold. frequency will become a stable mode and vice versa; if the determinant becomes negative for some frequency, then that mode will become unstable. The determinant detðJÞ will increase if 1 þ a2ðs0ðp0Þ^ws  a1Þ . 0, which will occur for larger ^wsðkÞ which occurs at smaller frequencies. Notably, the 0 frequency homogeneous solution will no longer give a zero eigenvalue but will be stable at the steady state (as shown in figure 10). This will also prevent the metastability that we saw in previous model variants. Downloaded from https://royalsocietypublishing.org/ on 05 If an unstable eigenvalue, λ, occurs, then its correspond- ing eigenvector will be l þ ðf þ gs0Þ ðf þ gs0Þðs0ðp0Þ^wsðkÞ  a1Þ   : ðC 12Þ ðC 12Þ Downloaded from https://royalsocietypub Conversely, the determinant will decrease for some wave- lengths if 1 −α1α2 < 0; that is if there is sufficient competition. This will occur for smaller values of ^wsðkÞ which are shorter wavelength, typically out of phase, perturbations. As λ > 0 and (f + gs0) > 0, this vector can only be out-of-phase if ðs0ðp0Þ^wsðkÞ  a1Þ , 0. This occurs when there is sufficient competition (a1 . s0ðp0Þ^wsðkÞÞ. As ^w p1ðkÞ must have the same sign as ðs0ðp0Þ^wsðkÞ  a1Þ for patterning to occur at all, we must have ^w p1ðkÞ , 0 as well for out-of-phase spatial instability. C.3. Analysis of the effect of logistic growth and competition on the stability matrix In order to generate figure 5a,b, we initiate a two ‘bump’ and a three ‘bump’ solution with noise as can be seen in figure 11. To initialize these simulations, we begin with rectangular bumps of length 40 that give total average population 16 000 pe km2. The two ‘bump’ solution has a peak of 40 000 pe km2 and the three bump has 26 000 pe km2. These are seeded with 100 cosine perturbations of modes 11 to 111, each of random size up to ±2% of the peak. If needed, the total population is adjusted to ensure the average is still 16 000 pe km2. ðC 13Þ Interface 19: 20220176 18 0 0.2 0.4 0.6 –100 –80 –60 –40 –20 0 20 40 60 80 distance (km) 0 1 2 3 4 5 6 –100 –80 –60 –40 –20 0 20 40 60 80 –100 –80 –60 –40 –20 0 20 40 60 80 0 0.2 0.4 0.6 distance (km) distance (km) service density population density ×104 (b) Downloaded from https://royalsocietypubl Figure 11. Initial conditions that generated figure 5a,b, respectively. These two initial conditions both have the same total population. However, including com- petition in the model, one simulation gives in phase patterns only whereas the other gives secondary out-of-phase patterning. London give r ¼ 0:056, 0:051 and 0:040 respectively. There- fore, r = 0.05 seems a reasonable estimate for the intrinsic growth rate. The model presented here has the potential to shed further light on this in future work. For example, we show in figure 7 a simulation in which the β parameters vary line- arly over time, starting below and ending above their default values in table 1 bp1 ¼ 0:5 þ 0:006t; bs ¼ 1 þ 0:038t bp2 ¼ 5 þ 0:08t: ðF 1Þ Appendix F. Varying parameters temporally ðF 1Þ ðC 13Þ ðC 13Þ In this section, we wish to estimate the intrinsic growth rate, r, in equation (7.1). To do this, we fit a simple, one dimen- sional, logistic growth model of the form dp/dt = rp(1 −( p/c)) and fit for r, c and the initial condition p(1801). This is done using a process of minimizing the sum of squares between the model output and the historic data. These data are London and London borough census data from 1801 to 2011 [41]. The results for London can be seen in figure 12. The values for Inner, Outer and Greater Example dispersion relations can be seen in figure 10. As in previous cases, the trace will still be negative. Assuming p0, s0 remains unchanged (using equation (7.3)), detðJÞ ¼ detðJÞjr¼0 þ rp0ðf þ gs0Þ c (1 þ a2ðs0ðp0Þ^ws  a1Þ): ðC 14Þ If the determinant increases such that it becomes positive for some frequency k (and the trace is negative), then that 0 1 2 3 4 5 6 0 0.2 0.4 0.6 –100 –80 –60 –40 –20 0 20 40 60 80 –100 –80 –60 –40 –20 0 20 40 60 80 distance (km) service density population density ×104 (a) 0 1 2 3 4 5 6 0 0.2 0.4 0.6 0 1 2 3 4 5 6 –100 –80 –60 –40 –20 0 20 40 60 80 –100 –80 –60 –40 –20 0 20 40 60 80 –100 –80 –60 –40 –20 0 20 40 60 80 –100 –80 –60 –40 –20 0 20 40 60 80 0 0.2 0.4 0.6 distance (km) distance (km) service density service density population density population density ×104 ×104 (b) (a) ditions that generated figure 5a,b, respectively. These two initial conditions both have the same total population. However, including com- one simulation gives in phase patterns only whereas the other gives secondary out-of-phase patterning. 0 1 2 3 4 5 6 –100 –80 –60 –40 –20 0 20 40 60 80 service density population density ×104 (a) royalsocietypublishing.org/journal/rsif J. R. Soc. and In this paper, we have made the simplifying assumption that the parameters used are static over time. This assumption is necessary in order to make the mathematical analysis of the steady states possible. However, we acknowledge that there will have been many transitions between regimes over time, especially with the advancement of technology. For example, Borchert [42] identifies five epochs from sail-wagons (ca 1800) to the modern technological epoch. For simplicity, we assume there is no competition or growth; that is r = ap = α1 = 0. This simulation shows how increasing typical travel distances over time leads to exagger- ated agglomeration. Of course, growth, competition and other factors may complicate this further but this brief example shows something of the effect of socio-technological developments. and 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 0 1 2 0 1 2 0 2 4 0 1 2 0 1 2 3 0 1 2 3 1 2 3 4 0 2 4 0 2 4 0 1 2 3 0 1 2 3 0 2 4 0 1 2 3 0 1 2 3 0 1 2 0 1 2 3 0 1 2 3 0 1 2 3 0 2 4 0 1 2 3 0 5 10 15 0 2 4 0 2 4 0 1 2 0 2 4 0 1 2 3 0 1 2 0 2 4 6 0 1 2 2 4 6 0 1 2 3 0 2 4 2 4 6 1800 1850 1900 1950 2000 2050 1800 1850 1900 1950 2000 2050 1800 1850 1900 1950 2000 2050 0 1 2 3 4 5 6 0 1 2 3 4 5 0 2 4 6 8 10 historical data fitted estimate year year year population population population population population population population population population population population population population population population population population population population population population population population population population population population population population population population population population population population population year year year year year year year year year year year year year year year year year year year year year year year year year year year year year year year year year ×106 ×106 × 106 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 ×105 Inner london Outer london Greater london City of london Barking... Barnet Baxley Brent Bromley Camden Croydon Ealing Enfield Greenwich hackney Hounslow Hillingdon Havering Harrow Haringey Hammersmith... Islington Kensington... Kingstion... Lambeth Lewisham merton Tower H Sutton Richmond... and li i i i b h i h 1800 1900 2000 0 1 2 3 population year ×105 Hillingdon 1800 1900 2000 0 1 2 3 population year ×105 Hounslow 1800 1900 2000 0 1 2 population year ×105 merton 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 0 2 4 0 1 2 3 0 5 10 15 0 2 4 0 2 4 population population population population population year year year year year ×105 ×105 ×105 ×105 ×105 Islington Kensington... Kingstion... Lambeth Lewisham 1800 1900 2000 1800 1900 2000 0 2 4 0 1 2 population population year year ×105 ×105 Lewisham merton 1800 1900 2000 0 2 4 p p l ti year ×105 Lewisham Downloaded from https://royalsocietypubli 1800 1900 2000 1800 1900 2000 0 1 2 2 4 6 popu at o population year year ×105 ×105 Tower H Sutton 1800 1900 2000 0 2 4 6 population year ×105 Southmark 00 1800 1900 2000 1800 1900 2000 0 1 2 3 0 1 2 population population year year ×105 ×105 Richmond... Redbridge 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 0 1 2 3 0 1 2 0 2 4 6 population population population year year year year ×105 ×105 ×105 Richmond... Southmark Redbridge Newham population 1800 1900 2000 0 1 2 3 population year ×105 Waltham f 1800 1900 2000 0 2 4 population year ×105 Andsworth 1800 1900 2000 2 4 6 population year ×105 Westminster Figure 12. Graphs showing population data for London with the logistic growth model fitted. and Southmark Redbridge Newham Waltham f Andsworth Westminster gure 12. Graphs showing population data for London with the logistic growth model fitted. 1800 1850 1900 1950 2000 2050 0 1 2 3 4 5 year population ×106 Outer london 1800 1850 1900 1950 2000 2050 0 1 2 3 4 5 6 year population ×106 Inner london 1800 1850 1900 1950 2000 2050 0 2 4 6 8 10 historical data fitted estimate year population × 106 Greater london royalsocietypublishing.org/journal/rsif J. R. Soc. Interface 19: 20220176 19 19 blishing.org/journal/rsif J. R. Soc. Interface 19: 20220176 1800 1900 2000 0 1 2 3 year ×105 Brent 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 0 1 2 0 2 4 0 1 2 0 1 2 3 population population population population year year year year year 5 ×105 ×105 ×105 ×105 5 5 5 5 5 City of london Barking... Barnet Baxley Brent C d C d E li E fi ld G i h 1800 1900 2000 1800 1900 2000 0 1 2 0 2 4 population population population year year ×105 ×105 Barking... Barnet 1800 1900 2000 0 1 2 3 population year ×105 Bromley 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1 2 3 4 0 2 4 0 2 4 0 1 2 3 population population population population year year year year year year ×105 ×105 ×105 ×105 Camden Croydon Ealing E 1800 1900 2000 0 1 2 3 population year year ×105 Greenwich 00 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 0 2 4 0 2 4 0 1 2 3 0 1 2 3 0 2 4 population population population population population y y y y y year year year year year ×105 ×105 ×105 ×105 ×105 ×105 Camden Croydon Ealing Enfield Greenwich 1800 1900 2000 0 2 4 population y year ×105 hackney Downloaded from https://royalsocietypublishing.org/ on 05 May 20 800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 1900 2000 1800 0 1 2 3 0 1 2 0 1 2 3 0 1 2 3 0 1 2 3 population population population population population year year year year year ×105 ×105 ×105 ×105 ×105 ×105 5 5 5 5 5 5 Hillingdon Havering Harrow Haringey Hammersmith... References 1. United Nations. 2014 World urbanization prospects. The 2014 Revision. New York, NY: United Nations. 6. Rozenfeld HD, Rybski D, Gabaix X, Makse HA. 2011 The area and population of cities: new insights from a different perspective on cities. Am. Econ. Rev. 101, 2205–2225. (doi:10.1257/aer.101.5.2205) 7. Office for National Statistics. Lower layer super output area population estimates (supporting information). https://www.ons.gov.uk/peoplepopulationand community/populationandmigration/population estimates/datasets/lowersuperoutputareamidyear populationestimates (accessed: 8 February 2021). 8. Clark C. 1951 Urban populationdensities. J.R. Stat. Soc. Ser. A (General) 114, 490–496. (doi:10.2307/2981088) 9. Newling BE. 1969 The spatial variation of urban population densities. Geogr. Rev. 59, 242–252. (doi:10.2307/213456) 10. Bertaud A. 2004 The spatial organization of cities: deliberate outcome or unforeseen consequence? WP 2004-01. Berkeley, CA: Institute of Urban and Regional Development, UC Berkeley. 6. Rozenfeld HD, Rybski D, Gabaix X, Makse HA. 2011 The area and population of cities: new insights from a different perspective on cities. Am. Econ. Rev. 101, 2205–2225. (doi:10.1257/aer.101.5.2205) 6. Rozenfeld HD, Rybski D, Gabaix X, Makse HA. 2011 The area and population of cities: new insights from a different perspective on cities. Am. Econ. Rev. 101, 2205–2225. (doi:10.1257/aer.101.5.2205) 2. Rickwood P, Glazebrook G, Searle G. 2008 Urban structure and energy—a review. Urban Policy Res. 26, 57–81. (doi:10.1080/08111140701629886) 11. Fujita M, Ogawa H. 1982 Multiple equilibria and structural transition of non-monocentric urban configurations. Reg. Sci. Urban Econ. 12, 161–196. (doi:10.1016/0166-0462(82) 90031-X) 11. Fujita M, Ogawa H. 1982 Multiple equilibria and structural transition of non-monocentric urban configurations. Reg. Sci. Urban Econ. 12, 161–196. (doi:10.1016/0166-0462(82) 90031-X) 7. Office for National Statistics. Lower layer super output area population estimates (supporting information). https://www.ons.gov.uk/peoplepopulationand community/populationandmigration/population estimates/datasets/lowersuperoutputareamidyear populationestimates (accessed: 8 February 2021). 7. Office for National Statistics. Lower layer super output area population estimates (supporting information). https://www.ons.gov.uk/peoplepopulationand community/populationandmigration/population estimates/datasets/lowersuperoutputareamidyear populationestimates (accessed: 8 February 2021). 3. Newman PG, Kenworthy JR. 1989 Cities and automobile dependence: an international sourcebook. 4. Cramer V, Torgersen S, Kringlen E. 2004 Quality of life in a city: the effect of population density. Soc. Indic. Res. 69, 103–116. (doi:10.1023/B:SOCI. 0000032663.59079.0b) 12. Alonso W. 1964 Location and land use. Toward a general theory of land rent. Cambridge, MA: Harvard University Press. 8. Clark C. 1951 Urban populationdensities. J.R. Stat. Soc. Ser. A (General) 114, 490–496. (doi:10.2307/2981088) 8. Clark C. 1951 Urban populationdensities. J.R. Stat. Soc. Ser. A (General) 114, 490–496. (doi:10.2307/2981088) 9. Newling BE. 1969 The spatial variation of urban population densities. Geogr. Rev. 59, 242–252. (doi:10.2307/213456) 9. royalsocietypublishing.org/journal/rsif J. R. Soc. Interface 19: 20220176 25. 25. Huang Q, Parker DC, Filatova T, Sun S. 2014 A review of urban residential choice models using agent-based modeling. Environ. Plann. B: Plann. Des. 41, 661–689. (doi:10.1068/b120043p) 15. Allen PM, Sanglier M. 1978 Dynamic models of urban growth. J. Soc. Biol. Struct. 1, 265–280. (doi:10.1016/0140-1750(78)90026-X) 34. Department for Communities and Local Government. English housing survey 2013 to 2014: household report. Chapter 6: tables, figures andannex tables. https://www.gov.uk/government/ statistics/english-housing-survey-2013-to-2014- household-report. 16. Wilson AG. 1970 Entropy in urban and regional modelling. London, UK: Pion Ltd. 26. Gilbert N, Hawksworth JC, Swinney PA. 2009 An agent-based model of the English housing market. In AAAI Spring Symp.: Technosocial Predictive Analytics, pp. 30–35. See https://www.aaai.org/ Papers/Symposia/Spring/2009/SS-09-09/SS09-09- 007.pdf. 17. Wilson AG, Oulton M. 1983 The corner-shop to supermarket transition in retailing: the beginnings of empirical evidence. Environ. Plann. A 15, 265–274. (doi:10.1068/a150265) 35. Greater London Authority. Land area and population density, ward and borough. https://data.london.gov. uk/dataset/land-area-and-population-density-ward- and-borough (accessed: 5 February 2018). 27. Koppelaar R, Kunz H, Ravalde T. 2013 Review of current advanced integrated models for city regions. Prepared for UK Technology Strategy Board Future Cities Catapult, London, under contract no. REQ010006 by the Institute for Integrated Economic Research and Imperial College London on behalf of the Ecological Sequestration Trust. See https:// ecosequestrust.org/wp-content/uploads/2015/02/ TSB-Report-Final-2013-04-16.pdf. 18. Fry H, Smith F. 2017 Rate effects on the growth of centres. Eur. J. Appl. Math. 28, 221–242. (doi:10. 1017/S0956792516000231) 36. Greater London Authority. Land use by borough and ward. https://data.london.gov.uk/dataset/land-use- ward (accessed: 5 February 2018). 19. Zincenko A, Petrovskii S, Volpert V, Banerjee M. 2021 Turing instability in an economic– demographic dynamical system may lead to pattern formation on a geographical scale. J. R. Soc. Interface 18, 20210034. (doi:10.1098/rsif. 2021.0034) 37. Office for National Statistics. Local area migration indicators, UK. https://www.ons.gov.uk/ peoplepopulationandcommunity/populationand migration/migrationwithintheuk/datasets/ localareamigrationindicatorsunited kingdom (accessed: 18 January 2021). rom https://royalsocietypublishing.org/ on 05 May 2022 Downloaded from https://royalsocietypublishing.org/ on 05 May 2022 28. Batty M. 2007 Cities and complexity: understanding cities with cellular automata, agent-based models, and fractals. New York, NY: The MIT Press. 20. Banerjee M, Petrovskii SV, Volpert V. 2021 Nonlocal reaction–diffusion models of heterogeneous wealth distribution. Mathematics 9, 351. (doi:10.3390/ math9040351) Downloaded from https://royalsocietypublishing.org/ on 05 M 38. Wang F, Guldmann JM. 1996 Simulating urban population density with a gravity-based model. Socio-Econ. Plann. Sci. 30, 245–256. (doi:10.1016/ S0038-0121(96)00018-3) 29. Waddell P. References Newling BE. 1969 The spatial variation of urban population densities. Geogr. Rev. 59, 242–252. (doi:10.2307/213456) 13. Bracken AJ, Tuckwell HC. 1992 Simple mathematical models for urban growth. Proc. R. Soc. Lond. A 438, 171–181. 5. Rossi-Hansberg E, Wright ML. 2007 Urban structure and growth. Rev. Econ. Stud. 74, 597–624. (doi:10. 1111/j.1467-937X.2007.00432.x) by dispersion and aggregation mechanisms. PLoS ONE 8, e80309. (doi:10.1371/journal.pone.0080309) by dispersion and aggregation mechanisms. PLoS ONE 8, e80309. (doi:10.1371/journal.pone.0080309) 14. Allen PM, Sanglier M. 1981 Urban evolution, self- organization, and decisionmaking. Environ. Plann. A 13, 167–183. (doi:10.1068/a130167) 33. Department for Transport. Why people travel (trip purpose) (NTS04). https://www.gov.uk/government/ statistical-data-sets/nts04-purpose-of- trips (accessed: 13 June 2018). 20 royalsocietypublishing.org/journal/rsif J. R. Soc. Interface 19: 20220176 2011 Integrated land use and transportation planning and modelling: addressing challenges in research and practice. Transp. Rev. 31, 209–229. (doi:10.1080/01441647.2010.525671) 21. Zincenko A, Petrovskii S, Volpert V. 2018 An economic–demographic dynamical system. Math. Modell. Nat. Phenomena 13, 27. (doi:10.1051/ mmnp/2018035) 39. Avitabile D. 2020 Numerical computation of coherent structures in spatially-extended systems. Zenodo. (doi:10.5281/zenodo.3821169) 30. Waddell P. 2002 UrbanSim: modeling urban development for land use, transportation, and environmental planning. J. Am. Plann. Assoc. 68, 297–314. (doi:10.1080/01944360208976274) 22. Santé I, García AM, Miranda D, Crecente R. 2010 Cellular automata models for the simulation of real- world urban processes: a review and analysis. Landscape Urban Plann. 96, 108–122. (doi:10.1016/ j.landurbplan.2010.03.001) environmental planning. J. Am. Plann. Assoc. 68, 297–314. (doi:10.1080/01944360208976274) 40. United States Census Bureau. TIGER/Line with selected demographic and economic data. https:// www.census.gov/geo/maps-data/data/tiger-data. html (accessed: 30 November 2018). Downloaded from https://royalsocietyp 31. Officefor National Statistics. Dataset: lower superoutput area population density (national statistics). https:// www.ons.gov.uk/peoplepopulationandcommunity/ populationandmigration/populationestimates/datasets/ lowersuperoutputareapopulationdensity (accessed: 8 June 2018). 23. White R, Engelen G. 1993 Cellular automata and fractal urban form: a cellular modelling approach to the evolution of urban land-use patterns. Environ. Plann. A 25, 1175–1199. (doi:10. 1068/a251175) 41. London Datastore. Historical census population. https://data.london.gov.uk/dataset/ historic-census-population (accessed: 3 February 2021). 42. Borchert JR. 1967 Simulating urban population density with a gravity-based model. Geogr. Rev. 30, 301–332. (doi:10.2307/212637) 32. Legendre P, Fortin MJ. 1989 Spatial pattern and ecological analysis. Vegetatio 80, 107–138. (doi:10. 1007/BF00048036) 24. Decraene J, Monterola C, Lee GKK, Hung TGG, Batty M. 2013 The emergence of urban land use patterns driven
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Diagnostic and prognostic value of MR-pro ADM, procalcitonin, and copeptin in sepsis
Open Medicine
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Open Medicine 2023; 18: 20230865 Diagnostic and prognostic value of MR-pro ADM, procalcitonin, and copeptin in sepsis https://doi.org/10.1515/med-2023-0865 received May 4, 2023; accepted November 5, 2023 and copeptin may be useful in the prognosis of sepsis and to predict the length of stay in hospital and mortality. https://doi.org/10.1515/med-2023-0865 received May 4, 2023; accepted November 5, 2023 Abstract: Sepsis is defined as life-threatening organ dys- function caused by a dysregulated host response to infec- tion. There is a need for biomarkers that can be used for the diagnosis of sepsis and the early identification of patients at high risk of death. In this study, we aimed to investigate the relationship between Mid-regional pro- adrenomedullin (MR-proADM), procalcitonin (PCT), and copeptin in sepsis. A total of 28 sepsis, 32 septic shock, and 30 control patients were included in our prospective study. Patients’ MR-proADM, PCT, and copeptin levels were recorded. Sequential organ failure assessment scores, length of hospital stay, and 30-day mortality were also recorded. These values were compared between the sepsis, septic shock, and control groups. The mean age of all participants was 64.04 ± 15.83 years. In the study, 37 (61.6%) patients were female and 23 (39.3%) were male. There was no statistically significant difference in gender/age between all patient groups and the control group (for all, p > 0.05). We found a significant difference between the survivors and nonsur- vivors in terms of MR-proADM, PCT, and copeptin levels. There was a significant difference between the sepsis and septic shock groups in terms of MR-proADM and PCT. A significant correlation was found between the length of hos- pital stay and MR-proADM and copeptin. MR-proADM, PCT, Keywords: sepsis, MR-proADM, copeptin, procalcitonin This work is licensed under the Creative Commons Attribution 4.0 International License. or(s), published by De Gruyter. This work is licensed under the Creative Commons Attribution 4.0 International License. Basar Cander: Department of Emergency Medicine, Bezmialem Vakif University, Istanbul, Turkey Emin Fatih Visneci: Department of Emergency Medicine, Konya City Hospital, Konya, Türkiye, e-mail: drfatihvisneci@hotmail.com Osman Karaoglan: Department of Emergency Medicine, Konya Numune Hospital, Konya, Turkey Fatma Cakmak: Department of Emergency Medicine, Erzurum City Hospital, Erzurum, Türkiye, e-mail: dr.fatmacak@gmail.com Alpay Tuncar: Department of Emergency Medicine, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey * Corresponding author: Bahadir Taslidere, Department of Emergency Medicine, Bezmialem Vakif University, Istanbul, Turkey, e-mail: drbahadir@yahoo.com ORCID: Emin Fatih Visneci 0000-0001-8050-4433; Fatma Cakmak 0000- 0002-5770-3554 Open Access. © 2023 the author(s), published by De Gruyter. This work is lice 2.2 Biochemical analysis Blood samples were obtained from all recruited patients within 24 h of presentation to the hospital by an indwelling arterial or venous catheter (if available) or by venipuncture. Patients with septic shock also had blood drawn every 24 h up to 120 h after admission. After the patients were diag- nosed with sepsis or septic shock (a blood sample was taken before giving antibiotics), 3 cc peripheral venous blood was taken into tubes (with ethylenediaminetetraacetic acid [EDTA]). Blood samples were centrifuged (3,000 rpm for 10 min) within the first hour after collection and stored at −80°C. The same procedure was applied in the control group. MR-proADM was measured in EDTA-K2 plasma sam- ples using the BRAHMS Kryptor Compact Plus method (Hennigsdorf, Germany). Copeptin was evaluated by Time- Resolved Amplified Cryptate Emission on the ultra-sensitive Kryptor compact Plus (Henningsdorf, Germany). PCT levels in serum were measured using reagents from Thermo Fisher Scientific. 2.3 Statistical analysis MR-proADM, PCT, and Copeptin values of the patient and control groups were compared. MR-proADM, PCT, and Copeptin values were compared in both patient groups (p-value 1, 2, 3). Data obtained in the study were statistically analyzed using the Statistical Package for Social Sciences software. Data were expressed as frequency (n), percen- tage (%), and mean ± standard deviation. The comparison of the distribution of categorical data was carried out with the “Chi-square (χ2) test”. The normality of the continuous variables was evaluated using the Kolmogorov–Smirnov test. The comparison of normally distributed parameters between more than two groups was made using a one-way analysis of variance. The comparison of non-normally distributed parameters between the two groups was per- formed with the Mann–Whitney U test, and the compar- ison between more than two groups was performed with the Kruskal–Wally’s test. Correlations between the para- meters were examined using Spearman’s analysis. p < 0.05 values were considered statistically significant. A receptor operating characteristic (ROC) curve analysis was applied for biomarkers. Ethics committee approval was obtained. The study was carried out in accordance with the Declaration of Helsinki. 2 and shock, and this increase shows that AVP release is increased and has diagnostic and prognostic value [14]. There is no gold standard method as a biochemical marker in the diagnosis and prognosis of sepsis. However, it is impor- tant to make a rapid diagnosis and start treatment early. In this study, we aimed to investigate the diagnostic and prog- nostic values of MR-proADM, PCT, and copeptin in sepsis. discharged patients was learned by following the new admissions to the hospital and by telephone on the 30th day. Following data collection, two emergency attending physicians independently reviewed the medical records 2 Materials and methods This is a single-center, prospective controlled study of sepsis patients visiting the Emergency Department (a tertiary care teaching hospital). A consecutive sampling method was used. This research was carried out between 01/12/ 2017 and 01/06/2018. Patients were selected according to the International Sepsis Conference criteria [1]. The criteria for inclusion were the fulfillment of two of four criteria for the systemic inflammatory response syndrome (fever or hypothermia, tachycardia, tachypnea, and leukocytosis or leucopenia) and systolic blood pressure no higher than 90 mm Hg (after a crystalloid-fluid challenge). Necessary consent was obtained from the patients and control group. Those who did not want to contribute to the conduct of the study were excluded from the study. Exclusion criteria were those under 18 years of age, pregnant women, stroke, myo- cardial infarction, pulmonary edema, seizure, trauma, need for emergency surgery, cancer, non-bacterial pneumonia, etc. Patients who were similar in age and gender and had no signs of infection were selected as the control group. A total of 28 sepsis, 32 septic shock, and 30 control patients were included in our study over a six-month period. The control group was compared with both patient groups (sepsis and septic shock) separately. The patient group was identified, and cases were randomly selected according to specific inclusion criteria. 1 Introduction Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to an infection [1–3]. Septic shock is the last and most severe stage of sepsis. The mortality rate is about 50–60% [4,5]. None of the clinical signs and symptoms traditionally used in the diagnosis of sepsis and laboratory findings are unique to sepsis. Therefore, there is a need for biomarkers that can be used for the diagnosis of sepsis and the early identifica- tion of patients [6,7]. Mid-regional pro-adrenomedullin (MR-proADM), the middle part of pro-adrenomedullin, consists of 45–92 amino acids and directly reflects plasma adrenomedullin (ADM) levels [8]. Circulating levels of bioactive adreno- medullin (BioADM) can be measured using new tech- nology and indicate vascular dysfunction occurring in sepsis. In this way, physiopathological deterioration in sepsis can be detected and progression to septic shock can be predicted [9]. ADM levels increase in sepsis, and MR-proADM has recently been shown to be a helpful prognostic tool in risk stratification in sepsis [10]. Procalcitonin (PCT) may aid in the diagnosis and man- agement of patients. PCT is a useful biomarker in severe bacterial infection. The sensitivity of PCT in sepsis ranges from 42 to 97%, and the specificity ranges from 48 to 100% [7]. Basar Cander: Department of Emergency Medicine, Bezmialem Vakif University, Istanbul, Turkey Emin Fatih Visneci: Department of Emergency Medicine, Konya City Hospital, Konya, Türkiye, e-mail: drfatihvisneci@hotmail.com Osman Karaoglan: Department of Emergency Medicine, Konya Numune Hospital, Konya, Turkey Fatma Cakmak: Department of Emergency Medicine, Erzurum City Hospital, Erzurum, Türkiye, e-mail: dr.fatmacak@gmail.com Alpay Tuncar: Department of Emergency Medicine, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey * Corresponding author: Bahadir Taslidere, Department of Emergency Medicine, Bezmialem Vakif University, Istanbul, Turkey, e-mail: drbahadir@yahoo.com ORCID: Emin Fatih Visneci 0000-0001-8050-4433; Fatma Cakmak 0000- 0002-5770-3554 Arginine vasopressin (AVP) is one of the most impor- tant hypothalamic stress hormones [11]. Copeptin is the C-terminal part of the prohormone of AVP or antidiuretic hormone [12]. Measurement of AVP is not commonly carried out in clinical practice. In contrast, copeptin can be immunologically tested with ease [13]. Copeptin increases rapidly in the plasma in conditions such as cardiovascular diseases, ischemic stroke, sepsis, Open Access. © 2023 the author(s), published by De Gruyter. This work is licensed under the Creative Co 2  Basar Cander et al. 3 Results the sepsis and septic shock groups (p = 0.02, p < 0.01, p = 0.04, respectively) (Table 2). The mean age of all participants was 64.04 ± 15.83 years. The mean age of all participants was 64.04 ± 15.83 years. The mean age of the sepsis group was 63.5 ± 16.11 years, the septic shock group was 64.1 ± 14.3 years, and the control group was 64 ± 15.34 years. There were 37 females (61.6%) and 23 males (39.3%) in the patient group, and 17 females (56.7%) and 13 males (43.3%) in the control group. There was no statistically significant difference in gender/age between all patient groups and the control group (for all, p > 0.05) (Table 1). There was no significant difference between the sepsis and septic shock groups in terms of mean PCT value (p > 0.05). However, a statistically significant difference was found between the sepsis and control groups and between the septic shock and control groups (p = 0.05, p < 0.01, respectively) (Table 2). When the mean copeptin values were evaluated; there was no significant difference between the sepsis, septic shock, and control groups in terms of the mean copeptin values (for all, p > 0.05) (Table 2). When the correlation between mortality and biomar- kers was evaluated, 32 of our patients were alive and 28 died. The mean MR-proADM value of the patients who survived was 3 nmol/L and the mean MR-proADM value of the patients who died was 5.12 nmol/L. There was a significant difference between the MR-proADM values of the patients who survived and nonsurvivors (p < 0.05). The mean PCT value of the patients who survived was 1.82 ng/mL and the mean PCT value of the patients who died was 13.85 ng/mL. There was a significant difference between the PCT values of the patients who survived and nonsurvi- vors (p < 0.05). The mean copeptin value of the patients who survived was 73 pmol/L and the mean copeptin value of the patients who died was 142 pmol/L. There was a significant difference between the copeptin values of the patients who survived and nonsurvivors (p < 0.05) (Table 3). 2.1 Data collection Patients’ demographic data were recorded when they were admitted to the emergency. Vital parameters (blood pres- sure, fever, pulse) and laboratory results (white blood cell, hemoglobin, hematocrit, platelet, urine output, urea, crea- tinine, sodium, potassium, total bilirubin, blood gas) were recorded on the forms. Sequential organ failure assessment (SOFA) scores of the patients were calculated. Length of hospital stay and 28-day mortality were recorded for the sepsis and septic shock groups. The mortality status of the Biomarkers in sepsis 3 3 Results Considering the correlation of hospital stays with biomarkers; a signifi- cant correlation was found between the MR-proADM and When the patients with sepsis were examined in terms of the infection focus, lung-based infection was observed, 26 (43.39%), urinary tract infection, 16 (26.6%), soft tissue infection, 10 (16.6%), intra-abdominal infection, 4 (6.6%), central nervous system infection, 3 (5%), and cardiac infec- tion, 1 (1.6%). When the mean MR-proADM values were evaluated; there were significant differences between the sepsis and control groups, the septic shock and control groups, and Table 1: Demographic, laboratory, and comorbidity Sepsis (n = 28) Septic shock (n = 32) Control (n = 30) Age Year 63.58 ± 13.9 64.06 ± 10.32 64.04 ± 15.83 PCT ng/mL 1.01 ± 4.11 15 ± 52.04 0.53 ± 3.73 MR-proADM nmol/L 2.19 ± 2.60 3.70 ± 8.90 1.07 ± 2.50 Copeptin pmol/L 67.5 ± 42.6 126 ± 245 51 ± 188 Gender Female, n (%) 37 (61.6) 17 (56.7) Male, n (%) 23 (39.3) 13 (43.3) DM n (%) 15 (25) 3 (10) HT n (%) 12 (20) 5 (16.6) COPD n (%) 6 (10) 4 (13) Malignancy n (%) 20 (33) 7 (23) CAD n (%) 5 (8.3) 3 (10) Other n (%) 6 (10) 4 (13) DM = diabetes mellitus, HT = hypertension, COPD = chronic obstructive pulmonary disease, CAD = coronary artery disease. Table 1: Demographic, laboratory, and comorbidity Table 3: The relationship between mortality and biomarkers M value p-value PCT A 1.82 ± 24.21 ng/mL <0.05 B 13.85 ± 51.43 ng/mL MR-proADM A 3 nmol/L <0.05 B 5.12 nmol/L Copeptin A 73 pmol/L <0.05 B 142 pmol/L A = survivors, B = non-survivors, and M = median. Table 3: The relationship between mortality and biomarkers DM = diabetes mellitus, HT = hypertension, COPD = chronic obstructive pulmonary disease, CAD = coronary artery disease. Table 2: Mean MR-proADM and PCT values of the groups Sepsis (n = 28) Septic shock (n = 32) Control (n = 30) p1 p2 p3 MR-proADM 4.8 ± 7.7 7.2 ± 7.1 2.1 ± 2.5 0.04 0.02 <0.01 PCT 10.6 ± 25.6 15.5 ± 34.6 1.6 ± 3.7 >0.05 0.01 <0.01 Copeptin 67.5 ± 42.6 126 ± 245 51 ± 188 >0.05 >0.05 >0.05 p1 values = between sepsis and septic shock, p2 = between sepsis and control group, and p3 = between septic shock and control group. 4  Basar Cander et al. 4  Basar Cander et al. Table 4: Correlation of biomarkers with the length of stay in hospital Biomarker r p-value MR-proADM 0.403 <0.01 PCT 0.202 >0.05 Copeptin 0.398 <0.01 r = correlation coefficient (among all patients). r = correlation coefficient (among all patients). copeptin and the length of stay in hospital (both, p < 0.05) (Table 4). Significant correlations were found between the mean MR-proADM, PCT, and calcitonin levels and SOFA scores. The sensitivity, specificity, positive predictive value (PPV), AUC, and negative predictive value (NPV) of the biomarkers examined in this study are given in Table 5. The data obtained are described in Figure 1 with the ROC curve. Figure 1: ROC curves. BioADM is a biomarker, which has been used for vas- cular and endothelial function and utility in sepsis [20]. We found that significant differences were found between the sepsis and septic shock groups and the control group in terms of MR-pro-ADM, and we were able to predict the prognosis, mortality, and length of stay in hospital using MR-pro-ADM. 4 Discussion According to the latest guidelines, treatment for sepsis should be individualized, and biomarkers should be used to tailor therapy to each patient’s needs [15,16]. Sepsis is a disease with high mortality and morbidity, and treatment should be initiated quickly. There is a need for an inexpen- sive, easily obtainable biomarker with high sensitivity and specificity in sepsis. Peptides are not just markers, peptides can also serve as mediators. Therefore, usage areas may differ [17,18]. In a study by Lai et al., the most common bacterial infection was pneumonia (40.2%) followed by bacteremia and urinary tract infections (23.5%), intra- abdominal infections (16.2%), and skin and soft tissue infec- tions (14.2%) [19]. Similarly, in our study, the most common infection was pneumonia followed by urinary tract infec- tion, soft tissue infection, and intra-abdominal infection. We think that this may be due to the increased incidence of ventilator-associated pneumonia due to the more fre- quent use of mechanical ventilators in patients followed up in the intensive care unit in recent years. Gille et al. evaluated copeptin levels in sepsis after burn injury and found no significant difference between patients with and without sepsis [21]. One study reported that Copeptin levels were higher than survivors in non- surfing [7]. In our study, in line with the literature, no statistically significant difference was found between the patients with sepsis or septic shock, and the control group, in terms of the levels of copeptin, which is released in equal amounts with AVP and is a more stable molecule in the blood. However, there was a significant difference between survivors and nonsurvivors. In a recent review by Di Somma and Crisanti with 773 patients investigating biomarkers in the management of sepsis, the median PCT value was found to be significantly higher in patients with culture-positive sepsis than in those with culture-negative sepsis [9]. In our study, there were Table 5: Sensitivity, specificity PPV, and NPV of biomarkers in all patients Biomarker Sen. (%) Spe. (%) PPV (%) NPV (%) AUC Cut-off MR-proADM 100 16.60 70 100 504 0.55 nmol/L PCT 91.30 50 78.50 75 793 0.5 ng/mL Copeptin 93 20 70 60 558 19 pmol/L NPV = negative predictive value, PPV = positive predictive value, Sen = sensitivity, Spe = specificity. 3 Results Table 2: Mean MR-proADM and PCT values of the groups p1 values = between sepsis and septic shock, p2 = between sepsis and control group, and p3 = between septic shock and control group. Figure 1: ROC curves. 4  Basar Cander et al. 4 Discussion Table 5: Sensitivity, specificity PPV, and NPV of biomarkers in all patients NPV = negative predictive value, PPV = positive predictive value, Sen = sensitivity, Spe = specificity. Biomarkers in sepsis 5 significant differences between sepsis, septic shock, and control groups regarding PCT values. [24]. In our study, SOFA scores were significantly correlated with the mean MR-pro ADM, PCT, and copeptin values, con- sistently with the literature [25,26]. In a study by Novotny et al., the sepsis-related mor- tality rate was 36%. PCT levels of nonsurvivors were found to be significantly higher than survivors. The authors con- cluded that PCT levels are an independent predictor of mortality in patients with sepsis [22]. In our study, we found a 30-day mortality rate of 46.6%. MR-proADM, PCT, and copeptin levels were compared between the patients who survived and nonsurvivors. Consistently with the lit- erature, we found a significant difference between the sur- vivors and nonsurvivors in terms of MR-proADM values. In addition, statistically significant differences were found between the survivors and nonsurvivors in terms of PCT and copeptin values. In the present study, we found a sig- nificant difference between the sepsis and septic shock groups in PCT. In light of these findings, we think that critical patients with high MR-proADM, PCT, and copeptin values have a higher mortality rate and these patients should be followed more closely. We think that these mar- kers can be used to determine mortality. In a study by Tsangaris et al., PCT concentration was 1.00 mg/L in sepsis patients and 0.18 mg/L in the controls. When the upper cut-offvalue for PCT was determined as 1.00 ng/mL, the sensitivity was 70%, specificity 91%, PPV 90%, and NPV 72% for patients with sepsis [27]. In our study, when the cut-offvalue for PCT was taken as 0.5 ng/mL, the sensitivity of PCT for the diagnosis of sepsis was 91.3%, specificity 50%, PPV 78.5%, and NPV 75%. When the cut-off value for copeptin was taken as 19 pmol/L, the sensitivity of copeptin for the diagnosis of sepsis was 93%, specificity 20%, PPV 70%, and NPV 60%. When the cut-offvalue for MR- proADM was taken as 0.55 nmol/L, the sensitivity of MR- proADM for the diagnosis of sepsis was 100%, specificity 16.6%, PPV 70%, and NPV 100%. In our study, although the sensitivity of copeptin and MR-proADM was high, the speci- ficity was low. 5 Study limitations In a study by Schneider et al. including 220 patients with sepsis, the median length of stay in the intensive care unit was found as 13 (4–95) days in the survivors. The median PCT values measured on the first postoperative day were found to be significantly higher in patients who died than in those who survived. In the same study, it was emphasized that there was a significant correlation between high PCT concentrations and prolonged hos- pital stay [23]. We think that copeptin and MR-proADM values of the patients in the control group may have been measured to be high since it is still not known precisely in which comorbid diseases copeptin and MR-proADM values increase. In our study, when the correlation between the length of hospital stay and PCT, copeptin, and MR-proADM was examined, no significant correlation was found between PCT and hospitalization time, unlike the literature. A significant correlation was found between the length of hospital stay and MR-pro ADM and copeptin. Both acute physiology and SOFA scores are widely used in critically ill patients [22]. In our study, SOFA scores were significantly correlated with the mean MR-pro ADM, PCT, and copeptin values, consistently with the literature [25,26]. 6 Conclusion A significant difference was found between copeptin, PCT, and MR-proADM values in surviving and non-surviving sepsis patients. A significant correlation was found between MR-proADM and copeptin and length of hospital stay. We think that MR-proADM, PCT, and copeptin may be used in predicting the prognosis of patients with sepsis, mortality, and length of stay in the hospital. Because of the complexity of the sepsis response, a single biomarker is unlikely to be sufficient. With its ability to respond quickly to clinical con- ditions, copeptin, PCT, and MR-proADM can be used for treatment follow-up and early diagnosis. In a study by Schneider et al., the median length of stay in the intensive care unit was 13 (4–95) days for the survi- vors [23]. In our study, when the correlation between the length of hospital stays and PCT, copeptin, and MR-proADM were examined, no significant correlation was found between PCT and hospitalization time, unlike the literature (p > 0.05). A significant correlation was found between the length of hospital stay and MR-pro ADM and copeptin (p < 0.05). SOFA scores are widely used to predict the outcome of critically ill surgical patients including those with sepsis References [1] Singer M, Deutschman CS, Seymour CW, Shankar-Hari M, Annane D, Bauer M, et al. The third international consensus defi- nitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016;315(8):801–10. [18] Wiedermann FJ, Kaneider N, Egger P, Tiefenthaler W, Wiedermann CJ, Lindner KH, et al. Migration of human monocytes in response to procalcitonin. Crit Care Med. 2002;30(5):1112–7. [19] Lai CC, Chen SY, Wang CY, Wang JY, Su CP, Liao ZH, et al. Diagnostic value of procalcitonin for bacterial infection in elderly patients in the emergency department. J Am Geriatr Soc. 2010;58:518–22. [2] Font MD, Thyagarajan B, Khanna AK. Sepsis and Septic Shock - Basics of diagnosis, pathophysiology, and clinical decision making. Med Clin North Am. 2020;104(4):573–85. [3] Rhodes A, Evans LE, Alhazzani W, Levy MM, Antonelli M, Ferrer R, et al. Surviving Sepsis campaign: international guidelines for Management of Sepsis and Septic Shock: 2016. Crit Care Med. 2017;45(3):486–552. [20] Voors AA, Kremer D, Geven C, Ter Maaten JM, Mebazaa A, Butler J, et al. Adrenomedullin in heart failure: pathophysiology and ther- apeutic application. Eur J Heart Fail. 2019;21:163–71. [21] Gille J, Schmidt J, Kremer T, Sablotzki A. Evaluation of MR-proANP and copeptin for sepsis diagnosis after burn injury. J Crit Care. 2019;52:149–55. [4] Elay G, Al B. Thirty-Day mortality in septic shock patients is directly associated with high disease severity score but not with the length of stay in the emergency department. Eurasian. J Emerg Med. 2020;19(3):172–7. [4] Elay G, Al B. Thirty-Day mortality in septic shock patients is directly associated with high disease severity score but not with the length of stay in the emergency department. Eurasian. J Emerg Med. 2020;19(3):172–7. [22] Novotny A, Emmanuel K, Matevossian E, Kriner M, Ulm K, Bartels H, et al. Use of procalcitonin for early prediction of lethal outcome of postoperative sepsis. Am J Surg. 2007;194(1):35–9. [5] Hotchkiss RS, Moldawer LL, Opal SM, Reinhart K, Turnbull IR, Vincent JL. Sepsis and septic shock. Nat Rev Dis Primers. 2016;2:16045. [23] Schneider CP, Yilmaz Y, Kleespies A, Jauch KW, Hartl WH. Accuracy of procalcitonin for outcome prediction in unselected postopera- tive critically ill patients. Shock. 2009;31(6):568–73. [6] Downes KJ, Fitzgerald JC, Weiss SL. Utility of Procalcitonin as a Biomarker for Sepsis in Children. J Clin Microbiol. 2020;58(7):e01851-19. [24] Basile-Filho A, Lago AF, Menegueti MG, Nicolini EA, de Brito Rodrigues LA, Nunes RS, et al. Conflict of interest: Authors state no conflict of interest. Conflict of interest: Authors state no conflict of interest. [14] Gomes DA, de Almeida Beltrão RL, de Oliveira Junior FM, da Silva Junior JC, de Arruda EPC, Lira EC, et al. Vasopressin and copeptin release during sepsis and septic shock. Peptides. 2021;136:170437. Data availability statement: The authors confirm that the data supporting the findings of this study are available. Raw data that support the findings of this study are avail- able from the corresponding author, upon reasonable request. [15] Rudd KE, Johnson SC, Agesa KM, Shackelford KA, Tsoi D, Kievlan DR, et al. Global, regional, and national sepsis incidence and mortality, 1990-2017: analysis for the Global Burden of Disease Study. Lancet. 2020;395(10219):200–11. [16] Baykara N, Akalın H, Arslantaş MK, Hancı V, Çağlayan Ç, Kahveci F, et al. Epidemiology of sepsis in intensive care units in Turkey: a multicenter, point-prevalence study. Crit Care. 2018;22(1):93. [17] Wiedermann FJ, Watzinger K, Stichlberger M, Joannidis M, Kaehler C, Lederer W. Effects of arginine vasopressin on migration and respiratory burst activity in human leukocytes. Open Med. 13(1):122–9. Funding information: No funds. Author contributions: Basar Cander: Study concept and design, supervision, materials, data collection and/or pro- cessing. Emin Fatih Visneci: Writing, analysis and/or inter- pretation. Osman Karaoğlan; Analysis and interpretation 6  Basar Cander et al. 6 of the data. Fatma Cakmak: Writing, supervision. Alpay Tuncar: technical, or material support, study supervision. Bahadir Taslidere; Statistical expertise, critical revision of the manuscript for important intellectual content, administrative. from the community and people with chronic kidney disease. J Clin Endocrinol Metab. 2014;99(12):4656–63. [13] Morgenthaler NG, Müller B, Struck J, Bergmann A, Redl H, Christ- Crain M. Copeptin, a stable peptide of the arginine vasopressin precursor, is elevated in hemorrhagic and septic shock. Shock. 2007;28(2):219–26. References The use of APACHE II, SOFA, SAPS 3, C-reactive protein/albumin ratio, and lactate to predict mortality of surgical critically ill patients: A retrospective cohort study. Medicine (Baltimore). 2019;98(26):e16204. [7] Pierrakos C, Velissaris D, BisdorffM, Marshall JC, Vincent JL. Biomarkers of sepsis: time for a reappraisal. Crit Care. 2020;24(1):287. [8] Krintus M, Kozinski M, Braga F, Kubica J, Sypniewska G, Panteghini M. Plasma mid regional pro adrenomedullin (MR- proADM) concentrations and their biological determinants in a reference population. Clin Chem Lab Med. 2018;56(7):1161–8. [25] Haag E, Gregoriano C, Molitor A, Kloter M, Kutz A, Mueller B, et al. Does mid-regional pro-adrenomedullin (MR-proADM) improve the sequential organ failure assessment-score (SOFA score) for mor- tality-prediction in patients with acute infections? Results of a prospective observational study. Clin Chem Lab Med. 2021;59(6):1165–76. [9] Di Somma S, Crisanti L. Can Acute Care Biomarkers Change Patient’s Management in Sepsis? Eurasian. J Emerg Med. 2022;21(2):79–85. [26] Jiang L, Feng B, Gao D, Zhang Y. Plasma concentrations of copeptin, C-reactive protein and procalcitonin are positively correlated with APACHE II scores in patients with sepsis. J Int Med Res. 2015;43(2):188–95. [10] Önal U, Valenzuela-Sánchez F, Vandana KE, Rello J. Mid-Regional pro-adrenomedullin (MR-proADM) as a biomarker for Sepsis and septic shock: narrative review. Healthcare (Basel). 2018;6(3):110. [11] Katan M, Morgenthaler N, Widmer I, Puder JJ, Konig C, Muller B, et al. Copeptin, a stable peptide derived from the vasopressin precursor, correlates with the individual stress level. Neuro Endocrinol Lett. 2008;29:341–6. [27] Tsangaris I, Plachouras D, Kavatha D, Gourgoulis GM, Tsantes A, Kopterides P, et al. Diagnostic and prognostic value of procalci- tonin among febrile critically ill patients with prolonged ICU stay. BMC Infect Dis. 2009;9:213. [12] Roussel R, Fezeu L, Marre M, Velho G, Fumeron F, Jungers P, et al. Comparison between copeptin and vasopressin in a population
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https://periodicals.karazin.ua/philology/article/download/14090/13253
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“Red Tomatoes” by B. Chichibabin: the poet’s path and the possibilities of the poem
Vìsnik Harkìvsʹkogo nacìonalʹnogo unìversitetu ìmenì V.N. Karazìna. Serìâ Fìlologìâ
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доктор филологических наук, профессор кафедры истории русской литературы, Харьковский национальный университет имени В. Н. Каразина; e-mail: shekhovt2@gmail.com; https://orcid.org/0000-0002-6270-6549 доктор филологических наук, профессор кафедры истории русской литературы, Харьковский национальный университет имени В. Н. Каразина; e-mail: shekhovt2@gmail.com; https://orcid.org/0000-0002-6270-6549 В статье проведен целостный семантический, поэтологический и контекстуальный анализ стихотворения русского поэта Бориса Чичибабина «Кончусь, останусь жив ли…» («Красные помидоры») с учетом дискуссионных моментов существующих интерпретаций. Уточнено значение этого произведения в личностном и творческом становлении поэта. Дополнена трактовка центрального символического образа стихотворения «красные помидоры» и предложен реальный комментарий к нему. Охарактеризованы архетипические, фольклорные и литературные претексты стихотворения. Прокомментировано соотношение внешнего, событийно-биографического, и лирического сюжетов. Прослежена семантическая нагрузка всех формальных компонентов стиха – композиции, строфики, фоники, метрики. Показано, что поэтическая конструкция оказывается едва ли не единственной опорой в разорванном, враждебном мире, где оказался узник, при этом наряду с классической строфикой поэт использует неклассическую метрику – размытый трехиктный дольник, демонстрируя возможности «свободного» стиха. Выявлены точки соприкосновения стихотворения Чичибабина с «семантической поэтикой», созданной О. Мандельштамом и А. Ахматовой (понимание связи истории и человека, проникновение творчества в жизнь, превращение слова в дело, соотнесенность стихотворения с реальной ситуацией, прозаизация стиха, сочетание обобщенно-философского и конкретно-чувственного и т. д.). Прозаизация стиха проявляется во введении сюжетных элементов, скрытой диалогизации, использовании разговорных интонаций, игре временами, кинематографичности. р р ц р р р ф Автор статьи приходит к выводу, что стихотворение молодого поэта становится свидетельством не просто ранней творческой зрелости, но и особой поэтической интуиции: обнаруживая повышенную семантизацию всех элементов стиха и реализацию перформативных возможностей поэтического высказывания, чичибабинский текст соотносится с перспективными художественными открытиями постсимволистской эпохи. р уд р Ключевые слова: Чичибабин, образ-символ, семантика, поэтика, контекст, реальный комментарий, «семантическая поэтика» Шеховцова Т. А. «Червоні помідори» Б. Чичибабіна: шлях поета і можливості вірша Шеховцова Т. А. «Червоні помідори» Б. Чичибабіна: шлях поета і можливості вірша У статті проведено цілісний семантичний, поетологічний і контекстуальний аналіз вірша російського поета Бориса Чичибабіна «Скінчуся, залишуся живим...» («Червоні помідори») з урахуванням дискусійних моментів існуючих інтерпретацій. Уточнено значення цього твору в особистісному і творчому становленні поета. Доповнено трактовку центрального символічного образу вірша «червоні помідори» і запропоновано реальний коментар до нього. Схарактеризовано архетипічні, фольклорні та літературні претексти вірша. Простежено семантичне навантаження всіх формальних компонентів вірша – композиції, строфіки, фоніки, метрики. Прокоментовано співвідношення зовнішнього, подієво-біографічного, і ліричного сюжетів вірша. Показано, що поетична конструкція залишається чи не єдиною опорою в розірваному, ворожому світі, де опинився в'язень, при цьому поряд з класичною строфікою поет використовує некласичну метрику – розмитий трьохіктний дольник, демонструючи можливості «вільного» вірша. Вісник Харківського національного університету імені В. Н. Каразіна Серія «Філологія». Вип. 81 Вісник Харківського національного університету імені В. Н. Каразіна Серія «Філологія». Вип. 81 УДК 821.161.1–1 Чичибабин.09 DOI: 10.26565/2227-1864-2019-81-10 «Красные помидоры» Б. Чичибабина: путь поэта и возможности стиха Т . А . Ш е х о в ц о в а  Літературознавчі дослідження: теоретичні та прикладні аспекти The author of the article comes to the conclusion that the poem written by young poet signifies not only his young creative maturity but also a special poetic intuition – while revealing an enhanced semantic character of all the elements of the poem and implementing the performative possibilities of the poetic expression, Chichibabin’s text correlates with the perspective artistic discoveries of post-Symbolistic epoch. p y p Keywords: Chichibabin, symbolic image, semantics, poetics, context, real comment, “semantical poetics” Лестницы, коридоры, хитрые письмена... Красные помидоры кушайте без меня [18, с. 24]. Лестницы, коридоры, хитрые письмена... Красные помидоры кушайте без меня [18, с. 24]. Стихотворение «Кончусь, останусь жив ли…», больше известное как «Красные помидоры», принято считать визитной карточкой Бориса Чичибабина и началом его оригинального поэтического пути. Неудивительно, что редкий из исследователей чичибабинского творчества обошел его стороной. История создания, историко-политический фон, центральный образ- символ, художественные достоинства этой шестнадцатистрочной миниатюры (лаконизм, скупость выразительных средств, оригинальная составная рифма, образно-смысловой сдвиг и т. п.) рассматривались неоднократно, с разной степенью подробности [1; 3; 7; 8; 13; 17]. Однако, как справедливо заметил Ф. Рахлин, «образный строй совершенного произведения поистине неисчерпаем» [13] (заметим, что столь же неисчерпаемыми оказываются его смысловая глубина, интертекстуальные и контекстуальные связи). Задача нашей статьи – семантический, поэтологический и контекстуальный анализ стихотворения Чичибабина, уяснение места этого произведения в личностном и творческом становлении поэта. Однако лирический сюжет стихотворения существенно расширяет смысловые горизонты. Первая строка сразу ставит самый главный для лирического героя вопрос и задает основную оппозицию стихотворения – «жизнь/смерть». Стих строится как движение маятника с максимальной амплитудой и передает ужас неопределенности в положении человека, который не знает, что у него впереди. Герой живет в ожидании того часа, когда маятник судьбы замрет в каком-либо определенном положении: жить – умереть. Причем вероятность выбора того и другого совершенно одинакова, и это подчеркивается фонетически: кончусь – останусь (4 звука совпадают из шести). Однако акцент сделан не на одной из этих возможностей, а на их последствии, которое, как ни парадоксально, объединяет противоположности. Зияющий провал, который рано или поздно закроется, зарастет – это, прежде всего, провал в личной судьбе (если «останусь жив»), поскольку тюремные месяцы и годы – время, как будто вычеркнутое из жизни. Но можно ли вычеркнуть их из памяти узника, что залечит («зарастит») раны его души? С другой стороны, конец чьего- либо личного существования, в особенности преждевременный, – провал в жизни страны и человечества, которая складывается из жизней отдельных людей. Но общая жизнь продолжится, даже если умрет поэт. доктор филологических наук, профессор кафедры истории русской литературы, Харьковский национальный университет имени В. Н. Каразина; e-mail: shekhovt2@gmail.com; https://orcid.org/0000-0002-6270-6549 А., 2019 64 Літературознавчі дослідження: теоретичні та прикладні аспекти доктор филологических наук, профессор кафедры истории русской литературы, Харьковский национальный университет имени В. Н. Каразина; e-mail: shekhovt2@gmail.com; https://orcid.org/0000-0002-6270-6549 р у р р д , д ру р Виявлено точки дотику вірша Чичибабіна з «семантичною поетикою», створеною О. Мандельштамом і А. Ахматовою (розуміння зв'язку історії і людини, проникнення творчості в життя, перетворення слова в справу, співвіднесеність вірша з реальною ситуацією, поєднання узагальнено-філософського і конкретно-чуттєвого і т. ін.) Прозаїзацїя вірша проявляється у введенні сюжетних елементів, прихованій діалогізації, використанні розмовних інтонацій, грі часом, кінематографічності. Автор статті приходить до висновку, що вірш молодого поета стає свідченням не просто ранньої творчої зрілості, а й особливої поетичної інтуїції: виявляючи підвищену семантизацію всіх елементів вірша і реалізацію перформативних можливостей поетичного висловлювання, чичибабінській текст співвідноситься з перспективними художніми відкриттями постсимволістської доби. Ключові слова: Чичибабін, образ-символ, семантика, поетика, контекст, реальний коментар, «семантична поетика» y p p p p The article presents a comprehensive semantic, poetological and contextual analysis of the poem Red Tomatoes («Кончусь, останусь жив ли…») written by the Russian poet Boris Chichibabin with consideration of debatable aspects of existing interpretations. The significance of this creation for the poet’s personal and creative formation has been specified. The interpretation of the poem’s key symbolic image has been amplified, and a real comment has been attached to it. Archetypical, folkloric and literary pretexts of the poem have been characterized. The correlation between the external, biographical and lyrical plots has been commented on. The semantic load of all formal components of the poem, such as composition, verse structure, phonics, and metrics, has been checked up. It has been shown that the poetic construction appears to be nearly the only support in a torn, hostile world, in which a prisoner found himself; at the same time, along with a classic verse structure, the poet uses non-classic metrics – a fuzzy three-ictus accentual verse, thus demonstrating the possibilities of a “free” poem. The meeting points of Chichibabin’s poem and the “semantical poetics”, created by Osip Mandelstam and Anna Akhmatova, have been detected (such as the understanding of the connection between history and a person, infusion of creation into life, turning words to deeds, relatedness of a poem to a real-life situation, prosaic character of the poem, combination of the generalized and philosophical notions with the specific and sensual ones, etc.) The prosaic character of the poem is reflected in the introduction of the elements with a plot, hidden dialogue, the use of colloquial intonations, playing with tenses, as well as the cinematic hints.  Шеховцова Т. Літературознавчі дослідження: теоретичні та прикладні аспекти Образ взят, вероятно, из византийской военной техники: греки из больших труб метали огонь на русские корабли и тем сжигали их; эти огнеметные трубы, изображаемые на миниатюрах, и являются, очевидно, прообразом “пламенного рога”, с помощью которого богиня печали сеяла тоску по Руси» [14]. Поэт пишет о своей личной трагедии – о потере свободы, но эта трагедия становится бедой всей страны, причем не только нынешней, но и во все века истории. Тяжко голове без плеч, телу без головы, Русской земле без Игоря, как говорил неизвестный автор древнерусского памятника. Необычная рифма – начальная, гипердактилическая (ударение на четвертом слоге от конца) в Игоревом – выгорела акцентирует внимание читателя на исторических параллелях, выделяет важную для автора мысль. является самым главным – оторванность от жизни во всех ее проявлениях, во всей ее сочной, красочной, чувственной полноте. Эта оторванность еще больнее, еще острее ощущается молодым и полным сил человеком. Красный цвет символизирует радость, красоту, любовь и полноту жизни, но его семантика поливалентна, он ассоциируется также с кровью, смертью, страданием. Два слова красные помидоры фонетически объединяет только звук «р», но он рассеян по всему стихотворению, обеспечивая доминирование центрального образа (зарастет провал, Игоревом – выгорела, трава, горькою, хитрые, коридоры, прозы – допросы). Образ- символ становится «центром вербальной звукоассоциативной сети» [4, с. 41]: зарастет – провал – трава – коридоры – прозы – горькою – вечером – допросы. Стихотворение насыщено аллитерациями и ассонансами, которые устанавливают фоносемантические связи между элементами поэтического текста. В эхо-повторах (эквифонии, по Г. Векшину [4, с. 6]) перекликаются не только отдельные звуки, но и звуковые группы: Игоревом – выгорела – коридоры – помидоры – горькою – головой (семантика горя / горечи распространяется на все фонетически сближаемые слова). Стихотворение насыщено аллитерациями и ассонансами, которые устанавливают фоносемантические связи между элементами поэтического текста. В эхо-повторах (эквифонии, по Г. Векшину [4, с. 6]) перекликаются не только отдельные звуки, но и звуковые группы: Игоревом – выгорела – коридоры – помидоры – горькою – головой (семантика горя / горечи распространяется на все фонетически сближаемые слова). Строка об Игоревом Путивле не только обращает к истории, но рождает дополнительные ассоциации, также сближающие прошлое и настоящее: выгоревшая трава – это напоминание о недавней войне и нынешнем выжженном репрессиями времени – и о войнах Древней Руси, о монголо-татарском нашествии, перекличка с теми строчками «Слова», где описана трава, поникшая от жалости после поражения Игорева войска. ) Слово «проза» в начальной строке третьей строфы («как я дожил до прозы») М. Літературознавчі дослідження: теоретичні та прикладні аспекти Стихотворение написано в одиночной камере на Лубянке летом 1946 года, где Чичибабин провел два месяца [18, с. 469]. Напомним, что в июне этого года Чичибабина, который учился на первом курсе филфака, арестовали и после тюремных и судебных мытарств присудили пять лет лагерей «за антисоветскую агитацию». Внешний, событийно-биографический сюжет стихотворения вполне прозрачен, и интерпретаторы «Красных помидоров» вполне закономерно рассматривают это произведение как стихи «о горькой участи юного узника, отторгнутого жестокой машиной государства от близких, от любимой, от молодости, счастья, книг, науки – а, может быть, и от самой жизни» [13], или же, более обобщенно, – о «насилии над человеческой душой» [7]. Вторая строка перекликается с четвертой: глагол «растет» притягивает существительное «трава». Оказывается, что провал (уже материализованный и из временной плоскости сместившийся в пространственную) должен зарастать травой, при этом поэт сближает эпохи и вспоминает, как когда-то выгорела трава в Игоревом Путивле. Обращение к «Слову о полку Игореве» разъяснено комментаторами вполне убедительно: стихи были написаны после второго семестра обучения на филфаке, включающего изучение древнерусской литературы, и несли целый ряд ассоциаций со «Словом…»: герой попадает в руки врагов, томится в неволе, его возлюбленная оплакивает его и просит о помощи и т. п. [3, с. 19]. Заметим только, что в «Слове о полку Игореве» нет прямого упоминания о выгоревшей траве. Однако вчерашний студент усвоил не столько букву, сколько дух древнего текста, сблизив в своем творческом сознании два фрагмента: «ничить трава жалощами» (никнет трава от жалости) и «Жля поскочи по Руской Кончусь, останусь жив ли, – чем зарастет провал? В Игоревом Путивле выгорела трава. Школьные коридоры – тихие, не звенят... Красные помидоры кушайте без меня. Как я дожил до прозы с горькою головой? Вечером на допросы водит меня конвой. Кончусь, останусь жив ли, – чем зарастет провал? В Игоревом Путивле выгорела трава. Школьные коридоры – тихие, не звенят... Красные помидоры кушайте без меня. Как я дожил до прозы с горькою головой? Вечером на допросы водит меня конвой. 65 Вісник Харківського національного університету імені В. Н. Каразіна Серія «Філологія». Вип. 81 земли, смагу людемъ мычючи въ пламянѣ розѣ» (Жля помчалась по Русской земле, сея горе людям из огненного рога) [16]. Как отмечал Б. Рыбаков, «Жля, Желя (Жьля) – олицетворение печали и тоски. В поэме она сжигает, душит горечью жара- смаги, который она извергает из огненного рога. Головушка горькая, головушка горькая… Ах, да пришла ночка темная. Ах, да пришла ночка темная. Не с кем ночку ночевать, осеннюю коротать… [5, с. 149]. Не с кем ночку ночевать, осеннюю коротать… [5, с. 149]. Літературознавчі дослідження: теоретичні та прикладні аспекти Богославский истолковал как унизительную реальность тюрьмы и допросов, увенчавшую «юношескую революционную романтику поэта» [3, с. 21]. На наш взгляд, упоминание о прозе отсылает к известным пушкинским строкам «Лета к суровой прозе клонят». Поэт с горькой иронией подчеркивает и преждевременность своего обращения к прозе, и полную противоположность пушкинской прозы «беллетристике» протоколов и доносов, где тоже царил вымысел. Слова «доносы» в стихотворении нет, но, даже если читатель не знаком с биографией Чичибабина, но хоть немного знает об атмосфере сталинской эпохи, он не может не услышать эту скрытую подтекстную рифму к «допросам». В стихотворении можно увидеть отголоски и еще одного университетского курса – фольклора. Протяжная лирическая песня о «горькой головушке», одиночестве и разлуке с любимой органично соотносится с третьей строфой стихотворения, дополняя смысловое и эмоциональное поле текста, расставляя акценты в лирическом сюжете: Головушка горькая, головушка горькая… Літературознавчі дослідження: теоретичні та прикладні аспекти 5. —UUUU—U (3) Школьные коридоры – 6. —UUUU— (4) тихие, не звенят... 7. —UUUU—U (3) Красные помидоры 8. —UU—U— (2) кушайте без меня. 9. —UU—U—U (1) Как я дожил до прозы 10. —UUUU— (4) с горькою головой? 11. —UUUU—U (3) Вечером на допросы 12. —UU—U— (2) водит меня конвой. 13. —UUUU—U (3) Лестницы, коридоры, 14. —UUUU— (4) хитрые письмена... 15. —UUUU—U (3) Красные помидоры 16. —UU—U— (2) кушайте без меня. Существует и вполне вероятная реальная подоплека данного образа. В романе И. Багряного «Сад Гетсиманский» переданы впечатления героя, находящегося в следственной тюрьме НКВД: «Наглядач розливав якусь руду юшку, що чомусь називалася борщем. Мабуть, тому, що була зварена з червоних помідорів. Від тих помідорів залишилися тонюнькі шкірочки, й крім тих шкірочок більше в «борщі» нічого не було – ані картоплини, ані капустини, ані тим більше чогось м’ясного, чогось від борщу. Гола червоняста юшка з шкірочками» [2]. После ареста в 1938 году Багряный два года находился в Харьковском следственном изоляторе УГБ-НКВД и в своем романе в значительной степени опирался на собственный тюремный опыт. Тюремное меню вряд ли особенно изменилось за годы, разделявшие двух заключенных, – прозаика и поэта. Общность метрического рисунка сближает отдаленные строки, внося новые смысловые оттенки. Так, схема (2) объединяет рефрен «кушайте без меня» со стихами «чем зарастет провал?» и «водит меня конвой». В таком контексте «провал» приобретает дополнительный смысл: это пропасть, отделяющая героя от его мучителей. Лирический герой Чичибабина отказывается от навязываемых ему «красных помидоров», и в этом его сила и достоинство. Главное, что он остается поэтом – хотя стихотворение небогато художественными «украшениями», в нем ощущается «поэтическая дерзость» – прежде всего в рифмах (составная, начальная, глубокая, гипердактилическая). Самых простых, глагольных рифм нет вообще – это не только придает некую изысканность простой стихотворной модели, но и подчеркивает безвыходность положения узника, обреченного либо на неподвижность в камере, либо на однообразные перемещения по строго определенному маршруту в замкнутом пространстве тюрьмы. у Детальный анализ стихотворения позволяет обнаружить в нем приметы так называемой «семантической поэтики», созданной О. Мандельштамом и А. Ахматовой и впервые описанной в знаменитой статье Ю. Левина, Д. Сегала, Р. Тименчика, В. Топорова и Т. Цивьян [11]. Речь, конечно же, не может идти о непосредственной причастности Чичибабина к художественным открытиям акмеистов, хотя некоторые сближения в этом плане уже имели место («Прихильне ставлення Б. Чичибабіна до творчості О. Літературознавчі дослідження: теоретичні та прикладні аспекти Мандельштама сприяло захопленню основними постулатами акмеїзму: утвердження реальних життєвих цінностей, конкретність і ясність земного, історичного, матеріального світу з привабливістю його чудових подробиць у реальному житті й просторі» [9]). Тем не менее важнейшая функция русской семантической поэтики, которая «послужила инструментом трансплантации культуры в условиях <…> культурного провала» [15, с. 247], чичибабинской поэзии близка, равно как близким оказывается восприятие творчества и истории. Детальный анализ стихотворения позволяет обнаружить в нем приметы так называемой «семантической поэтики», созданной О. Мандельштамом и А. Ахматовой и впервые описанной в знаменитой статье Ю. Левина, Д. Сегала, Р. Тименчика, В. Топорова и Т. Цивьян [11]. Речь, конечно же, не может идти о непосредственной причастности Чичибабина к художественным открытиям акмеистов, хотя некоторые сближения в этом плане уже имели место («Прихильне ставлення Б. Чичибабіна до творчості О. Мандельштама сприяло захопленню основними постулатами акмеїзму: утвердження реальних життєвих цінностей, конкретність і ясність земного, історичного, матеріального світу з привабливістю його чудових подробиць у реальному житті й просторі» [9]). Тем не менее важнейшая функция русской семантической поэтики, которая «послужила инструментом трансплантации культуры в условиях <…> культурного провала» [15, с. 247], чичибабинской поэзии близка, равно как близким оказывается восприятие творчества и истории. Классическая простота строфики (четыре катрена с перекрестной рифмовкой и чередованием женских и мужских рифм) также несет определенную смысловую нагрузку. В русской поэзии форма АbАb в катренах перекрестной рифмовки воспринимается как «образцово-классическая» [10, с. 128]. Число 4, по наблюдениям ученых, является образом статической целостности, идеально устойчивой структуры [12, с. 630]. Поэтическая конструкция оказывается едва ли не единственной опорой в разорванном, расшатанном, враждебном мире, где оказался юный узник. Кроме того, четырехчастная структура может быть соотнесена с символикой креста (не случайно в уже упомянутом «Саду Гетсиманском» метафора крестного пути является одной из центральных). Классическая простота строфики (четыре катрена с перекрестной рифмовкой и чередованием женских и мужских рифм) также несет определенную смысловую нагрузку. В русской поэзии форма АbАb в катренах перекрестной рифмовки воспринимается как «образцово-классическая» [10, с. 128]. Число 4, по наблюдениям ученых, является образом статической целостности, идеально устойчивой структуры [12, с. 630]. Поэтическая конструкция оказывается едва ли не единственной опорой в разорванном, расшатанном, враждебном мире, где оказался юный узник. Кроме того, четырехчастная структура может быть соотнесена с символикой креста (не случайно в уже упомянутом «Саду Гетсиманском» метафора крестного пути является одной из центральных). Не с кем ночку ночевать, осеннюю коротать… [5, с. 149]. Тогда «хитрые письмена» – это не только лживые записи следователей, протоколы допросов, но и письма-доносы, которые опускали некоторые современники Чичибабина в почтовый ящик у ворот КГБ. В таком контексте финальный повтор высвечивает в центральном символическом образе новое, дополнительное содержание. «Красные помидоры» – это и сытые, довольные лица следователей, и цвет красного знамени (красный издавна – цвет власти), и «кровавых костей в колесе» страшной машины сталинского правосудия, ужас Лубянки и Гулага. Тем самым в последней строфе меняется адресат рефрена – это уже не друзья, оставшиеся на свободе, а бездушные и ретивые исполнители воли «отца народов». Лейтмотивный образ «красные помидоры», центральный для стихотворения, возникает во второй строфе и повторяется в финале, завершая произведение. Образ многозначен, как и полагается символу. Исследователи истолковывают его в гастрономически-бытовом, биографическом и политическом аспектах: как намек на родной Харьков (на Украине помидоры – основной летний продукт), как указание на спелость и первосортность продукта, «конечно же, не достигавшего скудного стола заключенного» [7], как олицетворение «простого праздника жизни» и даже как символ советского строя [13]. Красные помидоры – это то, что отнято вместе со свободой и осталось в другой, нетюремной жизни. Повтор фиксирует внимание читателя на том, что для автора в этот момент 66 1. —UU—U—U (1) Кончусь, останусь жив ли, – 2.—UU—U— (2) чем зарастет провал? 3. —UUUU—U (3) В Игоревом Путивле 4. —UUUU— (4) выгорела трава. Літературознавчі дослідження: теоретичні та прикладні аспекти Пугачев вкладывает в исполнение энергическую экспрессию, бунтарство, непокорность, проклятие мучителям, вызов судьбе; он проигрывает как внешний, так и внутренний, лирический сюжет, расставляя смысловые акценты. Однако интонация абсолютного неприятия, убежденного противостояния и в том, и в другом прочтении очевидна. у ц ц р ) [ ] Помимо этих особенностей, присущих стихотворению Чичибабина, в «Красных помидорах» наблюдается и тенденция к «прозаизации», также характерная для семантической поэтики. Об этом свидетельствуют введение сюжетных элементов («вечером на допросы водит меня конвой»), скрытая диалогизация («кушайте без меня», обращенное к предполагаемому собеседнику), разговорные интонации (кончусь» вместо «умру»), игра временами (прошлое – настоящее – будущее), «кинематографичность» (на эту особенность обратил внимание М. Богославский: «Лестницы, коридоры, хитрые письмена» – «три выразительных кинокадра из фильма, который прокручивает память» [3, с. 20]). у ц ц р ) [ ] Помимо этих особенностей, присущих стихотворению Чичибабина, в «Красных помидорах» наблюдается и тенденция к «прозаизации», также характерная для семантической поэтики. Об этом свидетельствуют введение сюжетных элементов («вечером на допросы водит меня конвой»), скрытая диалогизация («кушайте без меня», обращенное к предполагаемому собеседнику), разговорные интонации (кончусь» вместо «умру»), игра временами (прошлое – настоящее – будущее), «кинематографичность» (на эту особенность обратил внимание М. Богославский: «Лестницы, коридоры, хитрые письмена» – «три выразительных кинокадра из фильма, который прокручивает память» [3, с. 20]). Стихотворение Чичибабина, в соответствии с законами семантической поэтики, воспринимается «как часть реальной ситуации – как вопрос или ответ, как реплика, просьба, молитва, заклинание, проклятие, как фрагмент, объясняемый именно из ситуации и синтезируемый в целое только при учете ситуации» [11]. Именно так «проходит путь, крестный путь поэта уже после “конца мира”, когда стихотворение – единственный посох, Стихотворение Чичибабина, в соответствии с законами семантической поэтики, воспринимается «как часть реальной ситуации – как вопрос или ответ, как реплика, просьба, молитва, заклинание, проклятие, как фрагмент, объясняемый именно из ситуации и синтезируемый в целое только при учете ситуации» [11]. Именно так «проходит путь, крестный путь поэта уже после “конца мира”, когда стихотворение – единственный посох, Таким образом, стихотворение молодого поэта становится свидетельством не просто ранней творческой зрелости и личностного «самостоянья», но и особой поэтической интуиции: обнаруживая повышенную семантизацию всех элементов стиха и реализацию перформативных возможностей поэтического высказывания, чичибабинский текст соотносится с перспективными художественными открытиями постсимволистской эпохи. Литература 1. Абрамович С. Д. Риторико-патетическое начало в художественном мире Б. Чичибабина: («Красные помидоры» как образ-литота чужого мира в стихотворении «Кончусь, останусь жив ли...») // Вестник Крымских чтений Б. А. Чичибабина: сб. науч. тр. Вып. 4: Б. А. Чичибабин в поэтическом мире России и Украины. Симферополь: Крымский Архив, 2008. С. 3–6. 2. Багряний І. Сад гетсиманський. URL: https://www.ukrlib.com.ua/ books/printit.php?tid=29 (дата обращения: 15.03.2019) Богославский М. Самостояние стиха, или встреча двух поэтик // Материалы Чичибабинских чтений. 1995 Харьков: Фолио, 1999. С. 13–28 с. 4. Векшин Г. В. Фоностилистика текста: звуковой повтор в перспективе смыслообразования: автореф. дис. … ок ора ф о а к: 10 01 02 «Р сск й з к» Моск а 2006 48 с 4. Векшин Г. В. Фоностилистика текста: звуковой повтор в перспективе смыслообразования: автореф. дис. … доктора филол. наук: 10. 01. 02 – «Русский язык». Москва, 2006. 48 с. 5. Великорусские народные песни / Изданы проф. А. И. Соболевским. Т. 5. Санкт-Петербург: Б. и., 18 Великорусские народные песни / Изданы проф. А. И. Соболевским. Т. 5. Санкт-Петербург: Б. и., 1899. 644 с. Г М Л Р й й ХХ // Т / П В Е Х 5. Великорусские народные песни / Изданы проф. А. И. Соболевским. Т. 5. Санкт-Петербург: Б. и., 1899. 644 с. 6. Гаспаров М. Л. Русский трехударный дольник ХХ века // Теория стиха / Под ред. В. Е. Холшевникова. Ленинград: Наука, 1968. С. 59–106. у у 6. Гаспаров М. Л. Русский трехударный дольник ХХ века // Теория стиха / Под ред. В. Е. Холшевникова. Ленинград: Наука, 1968. С. 59–106. 7. Егоров Б. Еда и питье у Бориса Чичибабина // «Пир – это лучший образ счастья» // Образы трапезы в богословии и культуре / Под ред. Светланы Панич и Ирины Языковой. Москва: Изд-во ББИ, 2016. 264 с. URL: http://ogrik2.ru/b/svetlana-panich/pir-eto-luchshij-obraz-schastya-obrazy-trapezy-v-bogoslovii-i-kulture/28673/boris-egorov- eda-i-pite-u-borisa-chichibabina/18 (дата обращения: 10.03.2019). 8. Егоров Б. Ф. Творческая жизнь Бориса Чичибабина. Санкт-Петербург: Росток, 2016. 192 с. 9. Зуєнко М. О. Особливості індивідуального стилю Бориса Чичибабіна: дис. … канд. філол. наук: 10.01.02 «Російська література». Полтава, 2007. URL: https://mydisser.com/ru/catalog/view/312/780/19869.html (дата обращения: 10.03.2019). 10. Илюшин А. А. Русское стихосложение. Москва: Высш. шк., 1988. 165 с. у 11. Левин Ю. И, Сегал Д. М., Тименчик Р. Д., Топоров В. Н., Цивьян Т. В. Русская семантическая поэтика как потенциальная культурная парадигма https://studfiles.net/preview/3349604/ (дата обращения: 10.03.2019). 11. Левин Ю. И, Сегал Д. М., Тименчик Р. Д., Топоров В. Н., Цивьян Т. В. Русская семантическая поэтика как потенциальная культурная парадигма https://studfiles.net/preview/3349604/ (дата обращения: 10.03.2019). Літературознавчі дослідження: теоретичні та прикладні аспекти р р р В числе основных характеристик семантической поэтики ученые называют необыкновенно развитое чувство историзма, соотносимость истории и человека, то есть переживании истории в себе и себя в истории, понимание связи истории с культурой, соотнесенности творчества с историей, вовлечение поэзии, творчества в жизнь, превращение слова в дело в неизмеримо больших масштабах, чем это мыслилось раньше: «Существенным становится только то, как человек (поэт) и история отразились друг в друге» [11]. История при этом воспринимается синхронично, что объясняет чичибабинское «стяжение» времен. Сам образ «красных помидоров» демонстрирует характерное для семантической поэтики, в особенности для поэзии Мандельштама, «тесное слияние смысловой Наряду с классической строфикой поэт использует неклассическую метрику – размытый трехиктный дольник, трех- или двухударный (в последнем случае – с пропущенным вторым «схемным» ударением [6]). В стихотворении присутствуют логаэдические строки:1 и 9 (1); 2, 8, 12 и 16 (2); 3, 5, 7, 11, 13, 15 (3); 4, 6, 10, 14 (4). 1. —UU—U—U (1) Кончусь, останусь жив ли, – 2.—UU—U— (2) чем зарастет провал? 3. —UUUU—U (3) В Игоревом Путивле 4. —UUUU— (4) выгорела трава. 67 Вісник Харківського національного університету імені В. Н. Каразіна Серія «Філологія». Вип. 81 линии, связанной с разработкой глобальных тем, со смысловыми линиями, трактующими конкретно-чувственное состояние мира (описание цвета, звука, осязания, вкуса, других зрительных или слуховых ассоциаций и проч.) [11]. помогающий пройти этот путь в мире, который “жесток и груб”» [11]. Заметим, что подобная ситуативно-актуальная трактовка, практически отождествляющая слово с действием, была предложена другом Чичибабина, актером и бардом Леонидом Пугачевым в замечательной песенной версии стихотворения. Интересно, что авторское чтение и исполнение Пугачева, интонационно и эмоционально во многом отличающиеся, не противоречат, а дополняют друг друга. Чичибабин читает медленно, напевно, несколько монотонно и отрешенно, подчеркивая мелодику стиха, его чтение напоминает молитву или заклинание. Пугачев вкладывает в исполнение энергическую экспрессию, бунтарство, непокорность, проклятие мучителям, вызов судьбе; он проигрывает как внешний, так и внутренний, лирический сюжет, расставляя смысловые акценты. Однако интонация абсолютного неприятия, убежденного противостояния и в том, и в другом прочтении очевидна. помогающий пройти этот путь в мире, который “жесток и груб”» [11]. Заметим, что подобная ситуативно-актуальная трактовка, практически отождествляющая слово с действием, была предложена другом Чичибабина, актером и бардом Леонидом Пугачевым в замечательной песенной версии стихотворения. Интересно, что авторское чтение и исполнение Пугачева, интонационно и эмоционально во многом отличающиеся, не противоречат, а дополняют друг друга. Чичибабин читает медленно, напевно, несколько монотонно и отрешенно, подчеркивая мелодику стиха, его чтение напоминает молитву или заклинание. Літературознавчі дослідження: теоретичні та прикладні аспекти Літературознавчі дослідження: теоретичні та прикладні аспекти 14. Рыбаков Б. А. Язычество Древней Руси. URL: https://www.e-reading.club/bookreader.php/86163/Rybakov_- _Yazychestvo_Drevneii_Rusi.html (дата обращения: 10.03.2019). _ y _ _ ( р ) 15. Сегал Д. Литература как охранная грамота. Москва: Водолей Publishers, 2006. 976 с. 16 С И // Б б Д й Р 15 / П 16. Слово о полку Игореве // Библиотека литературы Древней Руси: в 15 т. / Под ред. Д. С. Лихачева, Л. А. Дмитриева, А. А. Алексеева, Н. В. Понырко. Санкт-Петербург: Наука, 1997. Т. 4: XII век. URL: http://lib.pushkinskijdom.ru/Default.aspx?tabid=4941 (дата обращения: 10.03.2019). 16. Слово о полку Игореве // Библиотека литературы Древней Руси: в 15 т. / Под ред. Д. С. Лихач Дмитриева, А. А. Алексеева, Н. В. Понырко. Санкт-Петербург: Наука, 1997. Т. 4: XII в http://lib.pushkinskijdom.ru/Default.aspx?tabid=4941 (дата обращения: 10.03.2019). 17. Фризман Л. Г., Ходос А. Э. Борис Чичибабин. Жизнь и поэзия. Харьков: Консум, 1999. 128 с 18. Чичибабин Б. А. В стихах и прозе / Борис Чичибабин; изд. подгот. Л. С. Карась-Чичибабина, Л. Г. Фризман; [отв. ред. Б. Ф. Егоров]. Москва: Наука, 2013. 567 с. (Литературные памятники). References 1. Abramovich S. D. Ritoriko-pateticheskoe nachalo v khudozhestvennom mire B. Chichibabina: («Krasnye pomidory» kak obraz-litota chuzhogo mira v stikhotvorenii «Konchus, ostanus zhiv li...») // Vestnik Krymskikh chteniy B. A. Chichibabina: sb nauch tr Vyp 4: B A Chichibabin v poeticheskom mire Rossii i Ukrainy Simferopol: Krymskiy Arkhiv 1. Abramovich S. D. Ritoriko-pateticheskoe nachalo v khudozhestvennom mire B. Chichibabina: («Krasnye pomidory» kak obraz-litota chuzhogo mira v stikhotvorenii «Konchus, ostanus zhiv li...») // Vestnik Krymskikh chteniy B. A. Chichibabina: sb. nauch. tr. Vyp. 4: B. A. Chichibabin v poeticheskom mire Rossii i Ukrainy. Simferopol: Krymskiy Arkhiv, 2008. S. 3–6. 2. Bahrianyi I. Sad hetsymanskyi. URL: https://www.ukrlib.com.ua/ books/printit.php?tid=29 (data obras 15.03.2019) 3. Bogoslavskiy M. Samostoyanie stikha, ili vstrecha dvukh poetik // Materialy Chichibabinskikh chteniy. 1995–1999. Kharkov: Folio, 1999. S. 13–28 s. 4. Vekshin G. V. Fonostilistika teksta: zvukovoy povtor v perspektive smysloobrazovaniya: avtoref. dis. … doktora filol. nauk: 10. 01. 02 – «Russkiy yazyk». Moskva, 2006. 48 s. 5. Velikorusskie narodnye pesni / Izdany prof. A. I. Sobolevskim. T. 5. Sankt-Peterburg: B. i., 1899. 644 s. 6 G M L R ki t kh d d l ik KhKh k // T i tikh / P d d V Y Kh l h 6. Gasparov M. L. Russkiy trekhudarnyy dolnik KhKh veka // Teoriya stikha / Pod red. V. Ye. Kholshevnikova. Leningrad: Nauka, 1968. S. 59–106. 7. Yegorov B. Yeda i pite u Borisa Chichibabina // «Pir – eto luchshiy obraz schastya» // Obrazy trapezy v bogoslovii i kulture / Pod red. Svetlany Panich i Iriny Yazykovoy. Moskva: Izd-vo BBI, 2016. 264 s. URL: http://ogrik2.ru/b/svetlana- panich/pir-eto-luchshij-obraz-schastya-obrazy-trapezy-v-bogoslovii-i-kulture/28673/boris-egoroveda-i-pite-u-borisa- chichibabina/18 (data obrashcheniya: 10.03.2019). ( y ) 8. Yegorov B. F. Tvorcheskaya zhizn Borisa Chichibabina. Sankt-Peterburg: Rostok, 2016. 192 s. 9. Zuienko M. O. Osoblyvosti indyvidualnoho styliu Borysa Chychybabina: dys. … kand. filol. nauk: 10.01.02 «Rosiiska literatura». Poltava, 2007. URL: https://mydisser.com/ru/catalog/view/312/780/19869.html (data obrashchenyia: 10.03.2019). ) 10. Ilyushin A. A. Russkoe stikhoslozhenie. Moskva: Vyssh. shk., 1988. 165 s. Ilyushin A. A. Russkoe stikhoslozhenie. Moskva: Vyssh. s y y 11. Levin Yu. I, Segal D. M., Timenchik R. D., Toporov V. N., Tsivyan T. V. Russkaya semanticheskaya poetika kak potentsialnaya kulturnaya paradigma https://studfiles.net/preview/3349604/ (data obrashcheniya: 10.03.2019). 12. Mify narodov mira: entsiklopediya: v 2 t. / Gl. red. S. A. Tokarev. T. 2: K–Ya. Moskva: Sov. entsiklopediya, 1992. 719 s. Rakhlin F. Krasnye pomidory kushayte bez menya… URL: https://www.proza.ru/2011/06/25/1373 (data niya: 10.03.2019). y 14. Rybakov B. A. Yazychestvo Drevney Rusi. Литература 12. Мифы народов мира: энциклопедия: в 2 т. / Гл. ред. С. А. Токарев. Т. 2: К–Я. Москва: Сов. энциклопедия, 1992. 719 с. у ур р p p ( р ) 12. Мифы народов мира: энциклопедия: в 2 т. / Гл. ред. С. А. Токарев. Т. 2: К–Я. Москва: Сов. энциклопедия, 1992. 719 с. 13. Рахлин Ф. Красные помидоры кушайте без меня… URL: https://www.proza.ru/2011/06/25/1373 (дата обращения: 10.03.2019). 68 References URL: https://www.e-reading.club/bookreader.php/86163/Rybakov_- _Yazychestvo_Drevneii_Rusi.html (data obrashcheniya: 10.03.2019). 15. Segal D. Literatura kak okhrannaya gramota. Moskva: Vodoley Publishers, 2006. 976 s. 15. Segal D. Literatura kak okhrannaya gramota. Moskva: Vodoley Publishers, 2006. 976 s. 16 Slovo o polku Igoreve // Biblioteka literatury Drevney Rusi: v 15 t / Pod red D S Likhacheva L A Dmitriev 15. Segal D. Literatura kak okhrannaya gramota. Moskva: Vodoley Publishers, 2006. 976 s. 16. Slovo o polku Igoreve // Biblioteka literatury Drevney Rusi: v 15 t. / Pod red. D. S. Likhacheva, L. A. Dm 16. Slovo o polku Igoreve // Biblioteka literatury Drevney Rusi: v 15 t. / Pod red. D. S. Likhacheva, L. A. Dmitrieva, A. A. Alekseeva, N. V. Ponyrko. Sankt-Peterburg: Nauka, 1997. T. 4: XII vek. URL: http://lib.pushkinskijdom.ru/Default.aspx?tabid=4941 (data obrashcheniya: 10.03.2019). 17. Frizman L. G., Khodos A. E. Boris Chichibabin. Zhizn i poeziya. Kharkov: Konsum, 1999. 128 s. p y 18. Chichibabin B. A. V stikhakh i proze / Boris Chichibabin; izd. podgot. L. S. Karas-Chichibabina, L. G. Frizman; [otv. red. B. F. Yegorov]. Moskva: Nauka, 2013. 567 s. (Literaturnye pamyatniki) Шеховцова Тетяна Анатоліївна, доктор філологічних наук, професор кафедри історії російської літератури, Харківський національний університет імені В. Н. Каразіна (м. Харків, майдан Свободи, 4, 61022); e-mail: shekhovt2@gmail.com; https://orcid.org/0000- 0002-6270-6549 Шеховцова Татьяна Анатольевна, доктор филологических наук, профессор кафедры истории русской литературы, Харьковский национальный университет имени В. Н. Каразина (г. Харьков, пл. Свободы, 4, 61022); e-mail: shekhovt2@gmail.com; https://orcid.org/0000-0002-6270-6549 Tatiana Shekhovtsova, Doctor of Philology, Professor of the Department of Russian Literature, V. N. Karazin Kharkiv National University (Svobody Sq., 4, Kharkiv, 61022, Ukraine); e-mail: shekhovt2@gmail.com; https://orcid.org/0000-0002-6270-6549 69