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methadone is the first widely used drug to overcome the opioid withdrawal effects ( 1 , 2 ) . it acts by occupying the receptor affected by exogenous opioids leading to subsequent receptor activation .
this activation leads to closing of voltage - sensitive calcium channel ( vscc ) and stimulation of potassium efflux causing hyperpolarization and inhibition of adenylyl cyclase activity ( 3 , 4 ) .
successful approaches to pharmacotherapy in opioid addiction continue to rely largely on substitution of short - acting agonists such as heroin and oral administration of long acting high - efficacy agonists ( methadone ) or partial agonists ( buprenorphine ) ( 5 , 6 ) .
notably , all opioids that produce analgesia also can cause tolerance , addiction and withdrawal , and all of the available opioids are misused ( 7 ) .
it was shown that patients on long - term methadone maintenance treatment had longer qtc interval values than expected .
withdrawal symptoms among methadone maintenance therapy ( mmt ) patients had been reported to become worse and last longer than those of heroin or morphine due to extremely longer methadone half life ( 8) . low patient s retention rates in the mmt programme was also reported , making them prone to re - injecting behaviour ( 9 - 11 ) .
we believe that calcium channel blocking effect may play a crucial role in opioid dependent and withdrawal syndromes as shown by l - type voltage - dependent calcium antagonist role such as verapamil and felodipine in controlling the withdrawal syndromes effectively ( 12 - 15 ) .
both central and peripheral mechanisms play an important role in attenuating opioid withdrawal syndrome via calcium channel blocking agents ( 16 ) .
the effects produced by calcium channel blockers are proven to be independent from opioid receptor sites as there is no agents that can replace naloxone from its binding sites ( 17 ) .
one study has reported that blockade of l - type voltage - dependent calcium channels by calcium channel blockers is responsible for the attenuation of morphine withdrawal ( 18 ) .
other than that , t - type voltage dependent calcium channels have also been shown to play a critical role in the development of morphine dependence and withdrawal ( 19 ) .
previous study reported medicinal plants , nigella sativa , a scientific name for islamic prophetic medicine , habbatus sauda to have l - type calcium channel blocking effect ( 20 ) .
moreover , further study had also introduced its seeds as a novel treatment for opioid dependence and proven effective in long term treatment of opioid dependence ( 21 ) .
this plant has green to blue flowers with small black seeds and grows natively in temperate and cold climate areas .
the seed of n. sativa possesses a source of the main active ingredients such as thymoquinone , monotropens - like p - cymene and -pinene , nigellidine , nigellimine , and saponin ( 22 - 26 ) .
considering its low toxicity ( 27 - 29 ) , we hypothesized that the main active compound of n. sativa , thymoquinone ( tq ) , has a role in treating opioid withdrawal syndrome .
tq also exhibits calcium channel blocker properties via gut spasmolytic , tracheal , and airway relaxant , vasodilator and relaxant activities on the cardiac muscles ( 30 ) .
thus , further study is needed in order to explore the biochemical effects and mechanism of action of n. sativa at cellular level .
as a conclusion , we would like to suggest probably with the supplementation of n. sativa to methadone , it will indirectly be a starting point to answer the question of opioid dependency and withdrawal for better retention of patients in mmt . | methadone is widely being used for opioid substitution therapy . however , the administration of methadone to opioid dependent individual is frequently accompanied by withdrawal syndrome and chemical dependency develops .
other than that , it is also difficult to retain patients in the treatment programme making their retention rates are decreasing over time .
this article is written to higlights the potential use of prophetic medicines , nigella sativa , as a supplement for opioid dependent receiving methadone .
it focuses on the potential role of n. sativa and its major active compound , thymoquinone ( tq ) as a calcium channel blocking agent to reduce withdrawal syndrome and opioid dependency . |
laminins ( lms ) are abundant extracellular matrix ( ecm ) proteins present predominantly in basement membranes ( bm ) .
at least 16 isoforms have been described and named according to their specific trimeric combination of , and chains using the new nomenclature .
the existence of a lm-511 trimer ( 511 , formerly lm-10 ) was first reported in 199798 , some 15 y after the original discovery of laminin ( now named lm-111 , 111 trimer ) . given the more recent identification of lm-511 , our understanding of its specific function in normal tissues and in diseases has lagged on other lm isoforms , in particular lm-111 and lm-332 .
notably , the recognition of lm5 as a distinct lm subunit and the characterization of various antibodies against human lm chains have clarified earlier discrepancies regarding the distribution of lm-511 in normal human and mouse tissues and in neoplasia .
genetic ablation of lm5 in mouse marked the beginning of its functional characterization during development and later enabled investigations into the role of 5 laminins in specific organs .
functional studies in vitro and identification of lm-511 receptors have been facilitated by the triple cloning of recombinant human lm 5 , 1 and 1 chains as a rich source of intact lm-511 and the development of protocols for the purification of lm-511 from culture media .
together , these advances have contributed to the emerging view that lm-511 and its receptors regulate cancer progression .
studies documenting the high expression of lm-511 in several cancer types are briefly reviewed below and discussed in relation to more recent in vitro and in vivo experimental evidence indicating that lm-511 and its receptors regulate tumor cell migration , invasion and metastasis .
establishing the precise tissue distribution of lm-511 has been complicated by earlier studies assuming the existence of a single lm isoform .
hence , many of the antibodies used for immunohistochemical ( ihc ) detection of lms were raised against lm preparations containing more than one isoform ( e.g. , human placental laminin ) or against lm subunits / fragments now known to be present in multiple isoforms including lm-511 ( e.g. , 1 and 1 chains ) .
these problems were compounded by the fact that the 4c7 antibody previously used for the detection of lm1 chain actually recognizes the lm5 chain .
the latter study helped reconcile the discrepancies between the relatively restricted tissue expression reported for lm1 mrna and the broad lm5 mrna or protein distribution detected by the 4c7 antibody in human .
consequently , many of the earlier ihc studies need to be re - interpreted as evidence for the presence of lm-511 ( and in some cases lm-521 ) rather than lm-111 .
since the 1 and 1 subunits are present in multiple isoforms and expressed in most tissues , the presence of lm-511 trimers in a given organ is often assumed solely based on the detection of the 5 chain .
nevertheless , co - localization of all three subunits of lm-511 has been demonstrated more conclusively in many tissues by ihc or co - immunoprecipitation .
the results from these studies have shown that lm-511 is abundant in the basement membrane of most mature epithelia and endothelia and are consistent with lm-511 being the most widely distributed lm isoform in normal tissues and in carcinomas .
indeed , high expression of lm-511 subunits has been reported in many malignancies including colorectal , mammary , lung , thyroid , ovarian , prostate and basal cell carcinoma as well as in gliomas and melanomas .
however , the precise pattern of lm-511 expression varies significantly between tumor types , from a continuous bm localization to a more diffuse stromal or tumor cell expression , and its level in tumor cells or in the associated vasculature is influenced by the stage of tumor progression .
many studies have shown that the expression of lm-511 is often maintained or even increased in advanced tumors .
for example , nagle et al . used a combination of antibodies to analyze the expression of lm chains in normal prostate , prostatic intraepithelial neoplasia and prostate carcinoma specimens .
while the authors could detect the presence of multiple isoforms in normal prostate including 1 , 3 and 5 lms , they found a gradual loss of 1 and 3 isoforms whereas high expression of lm5 ( and therefore lm-511/521 ) was maintained in the majority of high grade tumors .
similarly , high tumor cell expression of all subunits of lm-511/521 has been reported in metastatic melanomas .
these observations raise the possibility that high expression of 5 lms may have prognostic significance in some tumor types .
consistent with this , detection of lm5 in tumor cells of non - small cell lung carcinoma patients was found to provide the strongest independent prognostic value to identify patients with high risk of disease recurrence .
a similar association is likely in breast carcinomas . despite the gradual loss of bm deposition often seen during breast cancer progression ,
it is clear that some lm ( unspecified isoform ) remains expressed in advanced tumors and in metastases .
high to moderate levels of lm-511 subunits have been reported in ductal carcinoma in situ , tubular carcinomas , fibroadenoma , atypical medullary carcinomas and carcinomas of no specific type .
our own investigation in a clinically relevant mouse model of spontaneous breast cancer metastasis revealed a direct correlation between tumor cell expression of lm-511 and metastatic potential .
in particular , bone metastatic 4t1.2 tumors showed widespread expression of lm-511 and this phenotype was maintained in distant metastases .
high tumor cell expression of lm-511 was observed also in advanced human breast cancers and bone metastases .
this is in contrast to the downregulation of lm-111 and lm-332 expression that occurs in most ( but not all ) advanced breast cancers due to a reduced number of laminin - producing myoepithelial cells and/or decreased expression of these isoforms through promoter methylation .
thus , we have argued that while the loss of lm-111 and lm-332 may contribute to the initial disruption of bm integrity and tissue organization , high levels of lm-511 ( or lm-521 ) in advanced breast tumors may be associated with increased risk of developing metastases and could predict poor clinical outcome . a more definitive demonstration of its prognostic value in breast cancer patients however ,
will require ihc analysis of lm-511 subunits in a large cohort of patients with known clinical outcome . nevertheless , it is noteworthy that lung , prostate and breast cancers , for which high expression of lm5 isoforms is most evident , have a high affinity for bone .
future studies should explore whether lm-511 expression has particular clinical relevance to tumors with a propensity to metastasize to bone . whether lm-511 expression is associated with a specific subtype of breast tumors
cell lines derived from the 4t1 mouse model of metastasis discussed above have a basal - like triple negative ( tn ) phenotype ( lack expression of estrogen receptor , progesterone receptor and her2/neu receptor ) ( ref .
interestingly , immunostaining of a small number of high grade human breast cancer specimens showed that expression of lm5 is not limited to a specific breast tumor subtype but its expression is considerably higher in tn tumors ( fig . 1 ) .
these observations further support a potential association between high lm-511 expression and aggressive metastatic cancers .
the predominance of lm-511 in advanced breast tumors however does not preclude a contribution by other lm isoforms during the early stage of tumor progression .
for instance , the presence of lm-332-producing myofibroblasts at the tumor - stromal interface has been demonstrated in some invasive breast tumors .
lm-332 is expressed also in tn tumors but it is not clear whether these represent a subset of breast cancer patients distinct from those with lm-511-expressing tumors .
representative ihc staining of lm5 in grade 3 luminal a , luminal b , her2 and tn human breast tumors showing highest expression ( brown ) in tn tumors .
consistent with tissue expression studies , many tumor lines synthesize , secrete and adhere to lm-511 in culture indicating that lm-511 mediates its effects in tumors partly via autocrine stimulation .
lm-511 is a more potent adhesive and migratory substrate than many other matrices in vitro including several lm isoforms and generally shows potency similar to that of lm-332 .
however , commercial preparations of placental lm-511 commonly used in earlier functional studies can be contaminated by other isoforms and may be less active than lm-511 purified from culture media due to proteolytic degradation .
nevertheless , it is clear that adhesion to lm-511 elicits a variety of tumor - specific cellular responses that are dictated in part by the repertoire and level of lm receptors expressed in each cell type as described below .
multiple receptors including integrins , lutheran / basal cell adhesion molecule ( b - cam ) and -dystroglycan , are known to bind lm-511 but integrins have been by far the most extensively documented in tumor cells .
for example , tani et al . reported that jar choriocarcinoma cells adhere to lm-511 via 61 integrin whereas panc-1 pancreatic adenocarcinoma cells utilize the 31 receptor even though both lines express both receptors .
attachment of huh-7 hepatocellular carcinoma cells to lm-511 involves at least three integrins , 11 , 31 and 61 .
in contrast , the human lung adenocarcinoma a549 cell line adheres to lm-511 exclusively through the 31 integrin . while be and m21 melanoma cells attach and migrate on recombinant lm-511 using both 31 and 61 integrins , we have shown that lim1215 colon cancer cells adhere and spread on lm-511 via multiple integrins including 21 , 31 and 64 , and their migration on this substrate is mediated by 31 and 64 .
simultaneous inhibition of all three receptors with function - blocking antibodies in lim1215 cells resulted in significant death .
many of the functions of lms in breast cancer progression and metastasis have been inferred from receptor studies . in particular , 31 , 61 and 64 lm - binding integrins
mediate the migration and invasion of breast tumor cells and/or promote their survival and proliferation at metastatic sites .
however , the functions of these receptors in vivo have been interpreted largely as evidence for the role of lm-111 or lm-332 rather than lm-511 in metastasis owing to its more recent identification .
interestingly , a study comparing the ligand - binding specificity of these integrins to various lm isoforms clearly showed that 31 and 61 bind to lm-511/521 ( purified from a549 lung carcinoma conditioned medium and containing predominantly lm-511 ) with higher affinity than to lm-111 or lm-332 .
integrin 64 was found to be selective for both lm-332 and lm-511/521 and to bind these isoforms with similar affinity . in light of these observations , it is probable that some of the functions assigned to lm - binding integrins in metastatic breast tumors are mediated through attachment to lm-511 .
recent results from our laboratory are consistent with this possibility . specifically , we reported that metastatic breast tumor lines adhere and migrate more efficiently on lm-511 than non - metastatic lines .
lm-511-induced haptotactic migration and invasion of human mda - mb-231 metastatic breast tumor cells were inhibited strongly by lebein-1 , a snake disintegrin targeting lm - binding 1 integrins , or an anti-3 integrin - blocking antibody .
similar antibody perturbation experiments with metastatic mda - mb-435 breast tumor cells showed that these cells utilize both 31 and 61 to migrate toward lm-511 ( unpublished observations ) .
interestingly , migration of mda - mb-231 and mda - mb-435 on lm-332 is 1-integrin dependent but not inhibited by a 3 or 6 antibody .
together , these data indicate that lm-511 may be a more relevant migratory substrate than lm-332 in metastatic breast tumors expressing 31 and 61 integrins .
lm-511-dependent haptotaxis and invasion of mouse mammary carcinoma lines were similarly inhibited by a 1 integrin - blocking antibody or by treatment with lebein-1 .
consistent with the pro - migratory / invasive properties of lm-511 , we found that soluble or coated lm-511 induces matrix metalloproteinase-9 expression in bone metastatic 4t1.2 cells and this activity could be blocked in vitro using the inhibitory lm5-derived a5g27 peptide . to further demonstrate the relevance of these lm-511-tumor interactions to metastasis in vivo
, we showed that selection of subsets of cells that migrate rapidly in response to lm-511 allowed the isolation of tumor variants more metastatic to multiple sites , particularly to bone .
importantly , enhanced metastasis was accompanied by a small increase in cell surface expression of 1 integrin and a more significant upregulation of 4 integrin .
this finding is likely to be highly clinically relevant given that 64 integrin associates most significantly with the aggressive basal - like subtype of breast cancer and predicts shorter time to recurrence and decreased survival .
the prognostic significance of lm and 64 integrin receptor expression in breast cancer patients was investigated in an earlier study by tagliabue et al .
they determined that the worst disease outcome was for patients with tumors co - expressing lm and 64 , suggesting the involvement of a lm - integrin autocrine loop in invasive breast tumors .
the precise isoform could not be identified in that study due to the use of polyclonal antibodies .
however , the authors noted that the lm antiserum used stained throughout the tumor areas in a manner analogous to the widespread lm-511 staining observed in mouse and human tn tumors ( fig . 1 ) .
if correct , blocking the production of lm-511 or the function / expression of its receptors would be expected to impact on metastatic potential . to begin to address this ,
we have generated variants of the 4t1.2 bone metastatic mammary carcinoma line with reduced lm-511 by stable retroviral expression of a short hairpin rna targeting the lm5 chain ( unpublished , manuscript in preparation ) .
ihc examination of lm5 in primary tumors 35 d post - implantation confirmed the sustained downregulation of lm5 compared with control tumors expressing a non - targeting construct ( fig . 2 ) .
as expected , lm5 suppression was evident in the tumor cells but not in the vasculature .
preliminary characterization of metastatic spread in these mice revealed a reduction in bone metastasis ( pouliot et al .
, these observations strongly support a direct functional contribution of lm-511 to breast cancer metastasis .
whether targeting lm5 also impact on the metastasis of other lm-511-expressing tumor types such as prostate or lung tumors is currently under investigation .
representative 4t1.2 primary tumors expressing a non - targeting shrna ( a ) or a lm5-targeting shrna ( b ) .
note the loss of lm5 in the tumor regions but not in the vasculature ( arrow ) .
the increasing experimental evidence linking lm-511 to cancer progression supports the notion that lm-511 has a much broader role in tumor invasion and metastasis than previously appreciated
. however , major questions remain regarding its prognostic significance , precise mechanism of action and potential as therapeutic target .
evidently , many advanced tumors express lm-511 and studies so far point to a possible association with bone metastasis and/or the basal - like / tn phenotype . whether lm-332 and lm-511-expressing tumors represent overlapping or distinct tn subsets also needs to be addressed .
a definitive answer to these questions will require a more in depth ihc analysis of larger cohorts of patients with known clinical outcome .
however , the 4c7 anti - lm5 antibody commonly used for this application does not work well on formalin - fixed paraffin embedded tissues , most likely because the 3d conformation of the epitope recognized by the 4c7 antibody in the lg13 modules of the lm5 chain is destroyed by tissue fixation and processing .
thus , the generation of more robust antibodies for staining of archival material should be a priority .
future studies will need also to clarify the precise contribution of lm-511 to the metastatic process and its relationship to lm-332 .
both isoforms have been implicated in tumor invasion and metastasis and share many of their receptors suggesting redundant functions . yet
, observations in various normal physiological processes indicate that lm-511 and lm-332 also have distinct , non - overlapping and sometimes opposing functions .
moreover , lm-511 promotes long - term proliferation and maintenance of pluripotency in stem cell cultures , whereas lm-332 enables proliferation but not pluripotency .
these properties could be relevant to metastasis and may be utilized by tumor cells at distinct stages of the metastatic cascade , including the epithelial to mesenchymal transition ( emt ) required for tumor cell invasion . for example , downregulation of lm-511 and lm-332 occurring in cells undergoing emt may be necessary to decrease the strength of adhesion and facilitate the early acquisition of a mesenchymal phenotype .
cells migrating away from the primary tumor , could utilize myofibroblast - derived lm-332 at the tumor - stroma interface .
conversely , re - expression of lm-511 at late stage of metastasis may provide the plasticity required for the reverse process of met and facilitate the re - establishment of a proliferative epithelial phenotype at metastatic sites .
this would be consistent with the recent demonstration that lm-511 promotes proliferation and partially blocks emt in human cells .
an interesting possibility is that these distinct lm-511 and lm-332-dependent adhesive responses during emt and met may be differentially regulated by cd151 , an important modulator of lm - binding integrins .
cd151 overexpression was shown recently to be an independent prognostic marker of poor overall survival in invasive breast cancer , particularly in quintuple negative breast cancer , a subtype of tn breast cancer .
a proposed model integrating these multiple lm-511 functions during metastasis is presented in figure 3 .
the model depicted above is based primarily on observations made in breast cancer metastasis models but incorporates also findings from studies in other tumor types as referenced below and in the text .
( 1 ) uncontrolled growth of the primary tumor and the loss of myoepithelial - derived lm-111 and lm-332 contribute to the initial disruption of tissue organization .
sustained expression of lm-511 further enhances the breakdown of the surrounding basement membrane through induction of mmp-2/9 gelatinases resulting in exposure of tumor cells to the surrounding stroma .
( 2 ) under the influence of stromal factors , tumor cells undergo emt and loss of cell - cell contacts .
snail - dependent downregulation of lm3 and lm5 may be required to reduce the strength of adhesive interactions and enhance 31 , 61 or 64 integrin - dependent cell motility .
subsequent stromal invasion may be achieved by interaction of tumor cells with low level of tumor - derived lm-511 and/or lm-332 derived from myofibrobalsts present at the tumor - stromal interface .
( 3 ) changes in the composition of lm isoforms in the tumor vasculature and the abundance of lm-511 are likely to contribute to tumor cell attachment and intravasation .
( 4 ) homing of circulating tumor cells ( ctc ) and invasion into metastatic sites is mediated through 31 integrin interaction with vascular lms ( including lm-511 ) and mmp-9 proteolytic activity .
binding of integrin 61 or 64 to endogenous lm-332 or lm-511 ( in organs rich in these isoforms ) promotes survival and growth of disseminated tumor cells ( dtc ) .
alternatively , enhanced expression of lm-511 and autocrine stimulation may be required in bone where lm-332 or lm-511 expression is more restricted to promote strong adhesion and 61/64-dependent tumor cell survival .
in addition , adhesion to lm-511 may provide the plasticity required for the process of met and the acquisition of a proliferative epithelial phenotype at metastatic sites . while current evidence supports the role of tumor - derived lm-511 in metastasis , the contribution ( if any ) of stromal / vascular lm-511 to metastasis is incompletely understood .
the availability of various animal models of metastasis ( e.g. , mmtv - pymt or 4t1 model ) in combination with conditional lama5 knockout mice could provide a useful in vivo platform to address this and guide future research .
the widespread expression of lm-511 in vivo makes direct targeting of this lm isoform impractical for cancer therapy .
for instance , many studies have employed inhibitory peptides derived from lms , including all lm-511 subunits , to demonstrate the clinical relevance of targeting lm-511 in vivo for anti - metastatic therapies .
some of these peptides were shown to exert either potent anti - metastatic activity in experimental models of melanoma metastasis to lung or bone or anti - angiogenic effects on mda - mb-231 mammary tumors in nude mice .
peptides may block metastasis by interfering with the function of tumor or host - derived lm-511 since lm-511 is also abundant in blood vessels , lung and bone sinusoids .
while peptides are unlikely to be useful for long - term therapy due to their short half - life in vivo , the above studies nevertheless provide proof of principle that targeting lm receptors could have therapeutic benefits .
disintegrin are a class of inhibitors increasingly investigated for their anti - tumor / metastatic activity .
lebein-1 , unlike most other disintegrins that target 3-type integrins via rgd sequences , has the unusual characteristic of being selective for laminin - type integrins , inhibiting the 31 , 61 and 71 integrins ( but not 11 and 21 collagen receptors ) in an rgd - independent manner .
our recent demonstration of its potent inhibitory properties against lm-511-mediated adhesion , migration and invasion in vitro provides the rationale for further testing in vivo .
consistent with this , pre - treatment of tumor cells with lebein-1 in vitro inhibits subsequent attachment to sinusoids and homing to the liver in vivo . understanding the molecular mechanisms by which lebein-1 interacts with lm-511 receptors and inhibits lm-511-mediated responses in tumor cells
metastasis is responsible for the majority of cancer - related death and remains a major clinical challenge despite extensive efforts over the past decades aimed at understanding and targeting cancer .
while much remains to be done , continuing research in the field of laminins could provide additional weapons to tackle this devastating disease and lead to the development of alternative strategies to prevent or delay metastatic progression . | laminins are major constituents of basement membranes .
at least 16 isoforms have now been described , each with distinct spatio - temporal expression patterns and functions .
the laminin-511 heterotrimer ( 511 ) is one of the more recent isoforms to be identified and a potent adhesive and pro - migratory substrate for a variety of normal and tumor cell lines in vitro . as our understanding of
its precise function in normal tissues and in pathologies is rapidly unraveling , current evidence suggests an important regulatory role in cancer .
this review describes published data on laminin-511 expression in several malignancies and experimental evidence from both in vitro and in vivo studies supporting its functional role during tumor progression .
a particular emphasis is put on more recent studies from our laboratory and that of others indicating that laminin-511 contributes to tumor dissemination and metastasis in advanced breast carcinomas and other tumor types .
collectively , the experimental evidence suggests that high expression of laminin-511 has prognostic significance and that targeting tumor - laminin-511 interactions may have therapeutic potential in advanced cancer patients . |
in much of rural india ,
local surface water is used for personal
and domestic hygiene and local groundwater is used for drinking and
cooking , with over half of rural households getting their drinking
water from tubewells . when contaminated
with fecal pathogens , these water sources can be a transmission route
for diarrheal disease . among fecal pathogens ,
the protozoa cryptosporidium and giardia are responsible
for the majority of detected waterborne disease outbreaks worldwide , and cryptosporidium has been
identified as a leading cause of moderate - to - severe diarrhea in indian
children < 2 years old . to reduce
diarrhea and other disease burdens ,
the government of
india has made significant investments to improve rural sanitation
through widespread promotion and construction of household pour - flush
latrines . under india
s total sanitation
campaign ( 20002012 ) , an estimated 95 million rural household
latrines were installed with government support ; millions more are
planned under its total sanitation for all campaign ( 20122022 ) .
leachate from pour - flush latrines and other on - site
sanitation , however , can contaminate local groundwater .
evidence exists
for bacterial and viral transport laterally up to 25 and 50 m , respectively ,
from latrines .
public health guidelines
for the distance between latrines and water points vary by country ,
with india recommending 310 m and others a distance equal
to 25 days travel time for leachate , but these guidelines can be difficult
to enforce in rural areas . to our knowledge , no published
studies have examined the impact
of pit latrines on groundwater contamination for cryptosporidium and giardia as indicated by a recent systematic
review .
one explanation for the gap is
an assumption that their larger size ( 418 m ) , compared
to bacteria ( typically < 5 m ) and viruses ( typically < 1
m ) , precludes cryptosporidium and giardia from being transported in groundwater over distances
required to reach wells .
although experimental
column studies of groundwater transport indicate a high rate of short - term
removal of cryptosporidium in the first few meters
of saturated sandy soils , they also show long - term ,
low - level transport of cryptosporidium at longer
distances , attributed to remobilization mechanisms that reverse initial
filtration / straining .
because both cryptosporidium and giardia can persist
for extended periods of time in soil and water ( > 3 months ) and both pathogens can cause infection at very
low dose , the public health threat from
long - term , low - level subsurface transport of cryptosporidium and giardia from latrines to wells requires further
examination in general , and particularly in the rural indian context
of rapid latrine expansion .
identifying the causes and implications
of environmental contamination
for cryptosporidium and giardia requires
consideration of additional contamination sources and processes beyond
groundwater contamination from latrines .
cryptosporidium and giardia can be shed by livestock and domestic
animals species , making it essential
to account for animal host sources and their proximity to water sources .
human open defecation which remains widespread in rural india , and postdefecation anal cleansing in surface
water bodies , present other nonpoint human sources and mechanisms
of surface and groundwater contamination .
additionally , environmental
processes , involving climate , hydrogeology , vegetation and soil for
example , mediate cryptosporidium and giardia transport and distribution in the environment , while the type , quality , and condition of the water point
( e.g. , private and public , damaged vs intact ) can have important impacts
on water source quality .
prior studies
have examined some of these processes , most often in isolation and
using fecal indicators or tracers , for either surface or groundwater
contamination , but rarely for both at the same time within the same
setting .
joint evaluation of local sources and processes of fecal protozoa
pathogen contamination for surface and groundwater together , accounting
for both animal and human fecal pollution , multiple transport pathways ,
and environmental and other mediators , has not been undertaken .
such
integrated study designs are needed to fully assess the public health
implications of protozoal contamination and contributions of latrines
as both a source and sink . in this study
, we investigate potential
causes of previously reported cryptosporidium and giardia contamination
observed concurrently in community surface and groundwater sources
during two monsoon seasons in 60 villages in puri district , odisha ,
india . these villages were part of a
large - scale cluster randomized controlled trial ( the odisha sanitation
trial ) of health impacts of improved household sanitation under a
total sanitation campaign intervention conducted in the district during
2011 .
we develop a conceptual hierarchical
model of local factors and processes causing protozoal contamination
for cryptosporidium and giardia in
surface and groundwater sources , and apply it to guide multivariable
modeling to test relationships between protozoal contamination in
a tested water source and water source characteristics , meteorological
conditions prior to sampling , the density of nonpoint sources of human
and animal fecal loading around each water source , including potential
subsurface leaching from household pour - flush latrine pits , and village - level
socio - economic ( ses ) characteristics as proxies for other mediating
factors .
much of the groundwater is held in shallow
unconfined and deeper semiconfined and confined aquifers , both primarily
composed of unconsolidated gravel and sands .
unconfined aquifer depth is variable , but can
reach 135 m below ground ( blg ) , whereas confined aquifers can reach
602 m blg .
other significant formations
include porous laterites and jointed / faulted formations susceptible
to weathering at depths of 20 m. the
climate is tropical and characterized by wet summers ( june to september )
and dry winters ( october to may ) , with much of the region experiencing
annual flooding during the southwest monsoon from june to september .
data and water samples for the 60 villages analyzed in this study
were collected as part of the odisha sanitation trial .
details of
the trial design , village selection , population characteristics , sanitation
intervention and pour - flush pit latrine design and construction can
be found elsewhere .
briefly , trial villages had similar
size , infrastructure , geography , and ses characteristics .
most households
( 62% ) lived below the indian poverty line and owned livestock ( 59% ) ,
with cattle an important host of zoonotic protozoa and the predominant
species owned ( 56% ) .
access to improved drinking water sources in
the form of government - installed ( deep ) or private ( shallow ) tubewells
was high ( 82% ) .
deep tubewells ( dtws ) were fitted with india mark
ii style handpumps ( maximum lift : 50 m ) , shallow tubewells ( stws )
had no .
6 style handpumps ( maximum lift : 7 m ) and both were expected
to be fully cased .
public ponds were
used for daily hygiene activities by more than 50% of households .
government subsidized pour - flush latrines had a single
circular leach pit of 1 m diameter , installed at ground level ,
extending 1 m deep .
self - financed
pour - flush latrines were similar , except with deeper pits ( 12
m ) , or two in series . during the monsoon season in some areas of puri
district
see supporting information ( si ) , figure s1 , map of villages . we previously reported results
of testing six water sources in each
village on a single day for cryptosporidium and giardia , comprising two public ponds , and two each of dtws
and stws ( when present ) , and protozoal shedding rates among humans ,
livestock and domestic animals in the region .
each source was sampled once in either 2012 or 2013 between june
and august .
samples were collected during the morning ( 8 am to 11
am ) and gps location and site observations recorded .
cryptosporidium was detected in 37% , 14% , and 5% , respectively , of ponds ( n = 94 ) , dtws ( n = 110 ) , and stws ( n = 96 ) and giardia was detected in 74% ,
12% , and 17% of sources , respectively .
see si , section s1 , for water processing
details and si , table s1 for pathogen concentrations .
we developed a conceptual model of multilevel
factors involved in cryptosporidium and giardia contamination of community ponds and tubewells ( figure 1 ) to aid investigation .
factors are categorized
as meteorological , loading from local human and animal sources of
fecal protozoa , water source - specific characteristics , or village - level
ses characteristics .
the top - level outlines factors that remain essentially
constant within each sampling season ( i.e. , 2012 or 2013 ) , such as
village ses characteristics , annual climatic pattern , and village - level
population of host animals , open defecators , latrines and latrine
users
. factors in the second level are those that vary during the
sampling season and affect day - to - day pollution levels , such as seasonal
cumulative rainfall , recent rain , or an extreme event .
the lowest
level represents factors that can vary hour - to - hour and affect pollution
levels at the time of sample collection , such as number of people
using the site . using the conceptual model we identified predictor
variables from data sets collected as part of the odisha sanitation
trial and available meteorological data .
conceptual model of multilevel
factors involved in cryptosporidium and giardia contamination of community water sources .
the three large boxes group factors hierarchically based of their
time scale or temporal stability .
arrows indicate direct and indirect associations / causality
between factors at different time scales and the outcome ( e.g. , level
of open defecators in a village has an effect on the local uses of
ponds , which in turn has an effect on the direct observations of human
uses at a pond ) .
cryptosporidium and giardia from
humans and from host species of domestic livestock in each village
were considered , accounting for the most common livestock host species
in puri district ( cattle , buffalo , goat , and sheep ) .
two local processes by which protozoal pathogens shed in
human feces can contaminate a pond are overland flow from nearby open
defecation fields and directly by people anal cleansing and bathing
in ponds after defecation .
people using the pond at the time of sampling
could also stir up settled microorganisms .
processes by which local
human feces can contaminate tubewell groundwater are through leaching
and groundwater transport from nearby latrine pits and from direct
infiltration of above - ground contaminated water at the tubewell head
via a damaged well pad ( platform ) or inadequate seal .
similar to human
fecal inputs , unmanaged livestock feces can reach ponds via overland
flow and directly if animals enter them and can reach tubewell groundwater
via direct surface infiltration at the well head if improperly sealed
or damaged .
weather conditions and events are presumed to mediate
the impacts of human and livestock fecal pollution sources on pond
and tubewell contamination , through mechanisms such as flushing or
dilution from rainfall or removal by ultraviolet decay .
ses factors
can also influence and mediate impacts of human and livestock sources
as ses groups may differ in their health status , affecting pathogen
shedding rates , or levels of access to improved sanitation and private
water sources , affecting practices at ponds and public tubewells ,
for example .
we obtained
rainfall data ( mm
day ) from four weather stations in puri district
beginning june 1 ( historical start of monsoon in odisha is june 10th )
for 2012 and 2013 . to estimate rainfall in each village
, we used the
thiessen polygon method as implemented in arcgis , version 10.2 ( esri ) .
the following rainfall variables were compiled and considered in analyses :
cumulative seasonal rainfall from june 1 until the day prior to sampling ;
occurrence of any rainfall and of an extreme daily precipitation event
during the 1 , 2 , and 3 days prior to sampling .
an extreme daily event
was defined as rainfall exceeding the 90th percentile of daily totals
between june and august in 2012 and 2013 ( i.e. , > 4 cm day ) .
variables were also developed for other meteorological
factors
from daily data from a regional station ( see si , tables s24 ) .
a village - wide
census and mapping of the location of each household and the sludge
pit of each pour - flush latrine was conducted between december 2012
and february 2013 as previously described . during the census
the following were collected : number of members
of each household , whether the household had a cattleshed at / near
the house , whether they owned a functional latrine , the household
members using the latrine , and the age of the latrine . because latrine
use by those with household access in the region is suboptimal , to account for potentially large differences
in loading rates of each census latrine in a village , we used reported
number of users and age of each household latrine at the time of the
census relative to the village s water sampling date to calculate
the number of person - years of latrine use as an estimate for fecal
loading at the time of water source sampling for each latrine pit
( details in si , section s3 ) . using
arcgis ,
version 10.2 ( esri ) , the numbers of households , cattlesheds ,
and latrines pits around each tested water source , within a series
of increasing buffer distances from the source , were counted ( si , figure s4 ) .
calculations were made at 5 m
intervals from 050 and 50 m intervals from 50200 m ,
followed by a single buffer at 500 m. using extracted data at each
buffer distance combined with village census data , the number of open
defecators ( associated with each household location ) , and person - years
of latrine use ( associated with each latrine pit location ) were calculated
( see si , sections s3 and 4 )
. using
baseline data on animal ownership from a representative sample
of households in each trial village , we
estimated village livestock populations from the average number of
animals owned by species per baseline household and the total number
of census households . trial baseline
data was also
used to estimate the following village ses characteristics : ( 1 ) illiteracy
rate among household heads , ( 2 ) fraction of households belonging to
a scheduled caste , and ( 3 ) fraction of households self - reporting ownership
of a poverty ration card ( i.e. , living below the indian poverty line )
as indicators of health status and behavioral factors .
characteristics and observations
recorded when sampling each water source and considered in the analysis
were number of people ( by age category and gender ) and of livestock
( by species ) at the site , types of uses of the water source , condition
of the tubewell pad ( intact , cracked , or missing ) , and color of the
water ( clear and not clear ) .
we
developed separate
multivariable models of protozoa contamination for cryptosporidium and giardia in each water source type to account
for different transport characteristics , sources , shedding rates ,
and survival of each microorganism , and different pathways involved
in contamination of each water source type . to build our statistical
models , we started with univariable analysis ( i.e. , one predictor
variable ) ( see lists of predictors , si , tables s216 ) .
initial multivariable models were constructed
by including predictor variables with a p - value 0.2
from univariable results . when greater than one predictor variable
representing the same factor qualified for inclusion , the one with
the smallest p - value was chosen , except for fecal
loading spatial variables , where both a near ( < 100 m ) and far ( 100
m ) distance were included .
we then used a backward selection approach and sequentially dropped each predictor variable
with a p - value > 0.2 , starting with the variable
with the largest p - value , to produce a final multivariable
model with all variable p - values 0.2 .
we
accounted for village clustering in final models using general estimating
equations ( gee ) .
statistical analyses
were performed using sas software , version 9.4 ( sas institute inc . ) .
prevalence of protozoa
contamination of ponds was high and oocyst / cyst concentrations varied
by up to 5 orders of magnitude , thus pond contamination was modeled
as concentration level in univariable and multivariable modeling using
gee for proportional odds cumulative logit regression ( also known
as ordered logistic regression).cryptosporidium and giardia concentrations
( oocysts / cysts 20 l ) were converted to log10 levels
( i.e. , < 1 parasite = 0 ; 110 = 1 ; 11100 = 2 ; so
on to 4 ) .
adjusted
odds ratios ( or ) were calculated to estimate the marginal likelihood
of one log - level higher concentration from a defined change in each
predictor variable .
cryptosporidium and giardia in
dtws and stws were modeled as binary
( presence / absence ) outcomes due to their much lower prevalence and
low concentrations and because tubewells are used for drinking .
indicate the marginal likelihood of tubewell protozoa contamination
for a defined change in each predictor variable .
we projected
future densities of person - years of latrine loading ( for the 2013
population density ) at critical distances around each sampled surface
and groundwater source in study communities and used these with final
multivariable models to estimate the impacts on water source protozoa
contamination of 100% pour - flush latrine usage in each study community
by 2017 ( the government of india s target ) and at the end of
the total sanitation for all campaign ( 2022 ) .
all other variables
were held constant ( see details , si , section s6 ) .
predictors of cryptosporidium and giardia contamination and their adjusted or
and p - values
in the final gee regression models for dtws and stws are shown in table 1 and for public ponds
in table 2 .
mean value of predictor variable
from subset of records with a value greater than zero .
mean value of predictor variable
from subset of records with a value greater than zero .
increased risk of protozoa detection in
stws was significantly correlated with human loading into nearby latrine
pits : 10 more person - years of latrine loading within 15 m of a stw
increased the odds of detecting cryptosporidium by
21% ( 95% or : 1.061.38 ) and , when occurring within 10 m , increased
the odds of detecting giardia by 44% ( 95% or : 1.121.85 ) .
weaker evidence for latrine leaching effects on dtws was also found .
each 10 person - years more of latrine loading within 500 m increased
the odds of cryptosporidium detection in a dtw by
1% ( p = 0.139 ) , while the same increase within 150
m increased the odds of giardia detection by 1% ( p = 0.050 ) .
only giardia detection in stws
was associated with any village - level ses characteristics .
a 5-percentage
point increase in the proportion of illiterate household heads decreased
the odds of detecting giardia by 8% ( 95% or : 0.890.97 ) .
specifically , cryptosporidium in stws was positively associated with the goat population ( or =
1.09 , 95% or : 1.031.14 , per three additional goats ) .
no other
associations were found between protozoa in shallow or deep tubewells
and livestock animal loading variables .
both protozoa were significantly
more likely to be detected in
groundwater from a dtw with a damaged well pad , at 7.10 times ( 95%
or : 1.9220.57 ) for cryptosporidium and 5.91
times ( 95% or : 1.1829.60 ) for giardia , than
from one with an intact pad .
we did not find statistically greater
odds of detecting protozoal pathogens in a damaged stw , however , stws
with a damaged pad had higher detection frequencies of both protozoa
( si , table s19 ) .
stws which were being
used immediately prior to sampling had significantly lower odds of
detecting giardia ( 0.26 , 95%or : 0.071.00 ) . in stws cryptosporidium
was significantly more
likely to be detected within 2 days after an extreme rain event ( or
= 12.91 , 95% or : 3.2651.10 ) , while giardia was significantly less likely to be detected as seasonal rainfall
increased ( or = 0.20 , 95% or : 0.110.39 , each 25 cm of seasonal
rainfall prior to sampling ) .
no rainfall variables were associated
with dtw contamination , however , both protozoa were detected in dtws
significantly more often in 2012 than in 2013 ( cryptosporidium or = 5.24 , 95% or : 1.3420.57 ; giardia or
= 36.14 , 95% or : 3.52371 ) .
protozoa
concentration levels in ponds were positively associated
with the number of people practicing open defecation living within
50 m of the pond but not at distances beyond that , and with village
illiteracy rates , recent use by cattle , populations of specific species
of livestock , sampling year , and antecedent rainfall patterns .
each
six additional people ( average household size ) practicing open defecation
and living within 50 m significantly increased the odds of a pond
having one log ( 10 times ) more cryptosporidium oocysts
( 20 l ) by 1.13 ( 95% or : 1.021.26 ) while
each additional 5% of households with an illiterate head significantly
increased the odds of one log more giardia concentration
by 1.22 ( 95% or : 1.061.42 ) .
neither signs of regular or recent
human use ( e.g. , paths ) nor human use observed at a pond prior to
sampling were associated with increased protozoa levels .
when
cattle were observed at a pond prior to sampling , we found some evidence
that the cryptosporidium concentration was likely
to be 10 times higher than when cattle were absent ( or = 5.33 , 95%
or : 0.6543.50 ) and when there were more cattlesheds within
200 m of a pond , the giardia concentration was likely
to be higher ( or = 1.06 , 95% or : 0.991.13 , each five additional
cattlesheds ) . we also observed associations between a village s
sheep and buffalo populations and pond parasite levels .
three additional
sheep significantly increased the likelihood of a higher cryptosporidium level ( or = 1.06 , 95% or : 1.011.12 ) , while three additional
buffalo ( mean number per buffalo - owning household ) had a nearly significant
protective effect on giardia concentrations ( or =
0.84 , 95% or : 0.701.01 ) .
conceptually , rainfall could
either flush oocysts / cysts into ponds
through overland flow or dilute concentrations by flooding or filling
ponds ; our analyses showed evidence of the effects of overland flow / flushing
on cryptosporidium concentrations and of dilution
on giardia concentrations in ponds , consistent with
the results for stws .
when rainfall occurred anytime during the 2
days prior to sampling , a pond s cryptosporidium concentration was 5.38 times ( 95% or : 1.2523.21 ) more likely
to be an order of magnitude higher than when it had been dry , while
each additional 25 cm of seasonal rainfall increased the probability
of a pond s giardia concentration being a
log10 level lower by 3% ( 95% or : 0.921.01 ) .
lastly , as found
for cryptosporidium in dtws , ponds in 2012 were significantly
more likely to have higher cryptosporidium concentration
levels than those sampled in 2013 ( or = 2.91 , 95% or : 1.207.05 )
all other effects constant .
model - derived predictions of local surface
and groundwater source
contamination rates for each protozoa during the monsoon season are
shown in table 3 for
projected latrine loading densities under 100% latrine coverage by
2017 and through 2022 . under projected full coverage , small predicted
reductions occur in the pond contamination rate for cryptosporidium ( 16% ) concurrently with large predicted increases in shallow and
deep tubewell groundwater contamination for each protozoa ( 1.94.1
times by 2022 ) over baseline 201213 rates , with the greatest
increases expected for cryptosporidium contamination
in stws .
calculated using predicted probabilities
from multivariable models in tables 1 and 2 for projected full latrine
use ( for tubewells ) and elimination of open defecation rates ( for
ponds ) at critical distances around each sampled water source in study
communities , by 2017 , and at end of total sanitation for all campaign
( 2022 ) . predicted probability
of either cryptosporidium or giardia contamination
estimated by summing the predicted detection probability of each protozoa
at a given water source
we investigated multiple sources and mechanisms for cryptosporidium and giardia contamination of community tubewells
and ponds across 60 villages in a coastal district in rural india
including pour - flush household latrines as a potential protozoa source
( or sink , via reduced open defecation ) .
multivariable modeling showed
that protozoa contamination of local groundwater used for drinking
was positively correlated with the density of human fecal loading
into latrine pits , literacy rates , livestock populations , damaged
tubewells , antecedent rainfall patterns and annual variability .
levels
of contamination of local ponds used daily for bathing and hygiene
were positively correlated with the number of residents practicing
open defecation nearby , illiteracy rates , livestock populations , antecedent
rainfall patterns and annual variability .
previous observational and experimental
studies have identified bacteria and virus groundwater contamination
from latrines up to 25 and 50 m away , respectively .
this is the first study to examine latrines simultaneously
as a source and sink of environmental protozoa contamination .
we found
strong evidence of protozoa contamination of shallow groundwater from
pour - flush latrines within 15 m and some limited evidence for deeper
groundwater contamination from pour - flush latrines up to 500 m away .
shallow tubewells in the study area draw water from < 7 m bgl and
during the monsoon period the water table can rise as high as 02
m bgl , making a hydraulic connection
between latrine pits ( 1 m bgl ) and shallow groundwater likely .
intermittent hydraulic connection between latrines pits and groundwater ,
persistence of protozoa in water and soil , and potential for long - term
protozoal transport support our finding of nearby latrine loading
as an important risk for shallow groundwater protozoal contamination
in this setting .
pathogen transport in deeper groundwater at
distances > 100 m from a pollution source , as detected in our study ,
is less often examined .
waterborne outbreaks of cryptosporidiosis
and giardiasis in north america linked to use of groundwater for drinking ,
however , provide evidence of deep groundwater protozoal contamination .
further evidence for the plausibility of deep
groundwater contamination at distance > 100 m comes from a study
of
artificial groundwater recharge using treated wastewater in which
both cryptosporidium and giardia were detected in groundwater at 320 and 500 m , respectively , from
recharge zones in fractured limestone .
the mostly porous gravels and sand aquifers in our study area may provide sufficient pore space for protozoal
transport , supporting the limited evidence ( 0.05 < p < 0.14 ) we also found for local latrines as a source of deeper
groundwater protozoal contamination . research on overland transport
of protozoa shows a clear connection
between animal fecal loading on land and contamination of nearby surface
water , with factors such as slope , soil type , and vegetation density
affecting transport . while human fecal loading on
land also poses risks for protozoa contamination of nearby surface
water ,
the circumstances and magnitude of benefits on surface water
protozoa contamination from ending open defecation in countries where
the practice remains prevalent have not been examined .
we observed
a significant relationship between the number of people living nearby
a pond who practiced open defecation ( within 50 m , not beyond ) and
the pond cryptosporidium concentration level .
genotyping
of contaminated pond samples in this and another similar rural setting
in bangladesh identified cryptosporidium hominis ( human - specific
genotype ) but not other genotypes .
together ,
these findings suggest that promoting latrine use by people living
nearby , and protective buffers around local water bodies , could reduce
human host - specific cryptosporidium pond contamination
in this setting .
reduced cryptosporidium contamination
of ponds from increased latrine uptake predicted in this setting is ,
however , overshadowed by the large expected negative effects of increased
uptake on protozoal contamination of local groundwater drinking sources
( table 3 ) .
village sheep , goats , and cattle appear to
be important local animal host contributors of cryptosporidium contamination detected in community water sources in this setting ,
while cattle in particular appear to contribute to giardia contamination .
unexpectedly , we observed a trend where villages
with more buffalo had lower levels of pond giardia contamination .
we know of no biological explanation for the association ,
which may be confounded . among livestock and domestic animal populations
in india and globally ,
however , evidence from a systematic review and other studies of
zoonotic disease transmission from livestock and cattle to humans
in this and similar settings is mixed .
overall , the public
health significance of exposure to protozoa shed by livestock and
domestic animals is case - specific since these animals can shed zoonotic
protozoa , infectious to humans , as well as host - specific genotypes .
rainfall
effects on protozoal surface water contamination have been studied , but few have considered human and nonhuman protozoa sources and
examined impacts on surface and groundwater contamination . over short
time scales ( i.e. , within the monsoon season ) our results indicate
that rainfall is an important mediator of local environmental sources
of human and animal fecal protozoal loading on contamination of ponds
and shallow groundwater .
positive associations between rainfall events
( i.e. , > 90th and > 80th percentile of monthly rainfall ) and
waterborne
disease outbreaks and fecal contamination , have been previously reported . in our modeling of stw and pond
contamination ,
rainfall variables associated with cryptosporidium contamination were different from those associated with giardia contamination , implying different physical processes
of importance .
cryptosporidium in stws and higher
concentrations in ponds were more likely after a recent event ( within
2 days ) suggesting short - term cyclical processes of environmental
loading and accumulation followed by contaminant flushing and transport
pulses .
on the other hand , giardia detection in stws
and concentration levels in ponds were negatively associated with
increasing cumulative rainfall ( monsoon season ) , suggesting dilution
of widespread background contamination .
these hypothesized contrasting
environmental processes are consistent with finding giardia to be much more ubiquitous ( higher endemic infection rates and orders
of magnitude more parasites shed per host ) than cryptosporidium in this setting and a similar environment .
after controlling for within - season shorter time - scale meteorological
effects , sampling year ( 2012 vs. 2013 ) , a potential proxy for longer
time - scale variability , remained associated with significant differences
in cryptosporidium and giardia contamination
in dtws , but not stws , and cryptosporidium in ponds .
characteristics and population - level patterns of infection for each
protozoa , as well as larger scale climatic and hydrogeological
conditions for which we were unable to account , may have played a
role .
village illiteracy rates
were the strongest predictor of increased giardia contamination levels in ponds , while at the same time were associated
with lower giardia risk in stws .
livestock ownership
in our study population at baseline was nearly equal among illiterate
and literate households ( 57% vs 60% ) , however , latrine ownership was
greater among literate households ( 13% ) compared to illiterate
households ( 3% ) and more illiterate households bathed at ponds
( 72% ) compared to literate households ( 55% ) . given similar animal
ownership but lower latrine use ( i.e. , higher open defecation ) and
higher pond bathing rates among illiterate vs. literate households ,
the link between illiteracy and increased pond giardia contamination would seem to point to a human source behind elevated giardia levels in ponds , that is , from higher overall rates
of open defecation and of anal cleansing and bathing in ponds in villages
with higher illiteracy rates .
the protective effect of illiteracy
on stw contamination may arise similarly from the lower overall village - wide
latrine uptake rate and its associated loading into shallow groundwater ,
or may be confounded .
wellhead
protection is
critical for preserving groundwater quality , and poor well condition has previously been linked to well water
fecal bacterial contamination .
our finding that dtws with damaged pads ( cracked or missing ) were
significantly associated with detectable levels of cryptosporidium and giardia , extends this link to larger protozoal
organisms in low - income settings .
interestingly , we did not find a
significant increased risk of contamination in stws with well pad
damage , possibly because private household stws are used less intensely
than public dtws .
stws used immediately prior to sampling were
significantly less likely to have detectable levels of giardia than those that had been idle .
the sample collected from such stws
may have included a larger volume of more distant and deeper cleaner
groundwater , which may have diluted the impact from nearby latrine
leaching .
we did not observe an effect on cryptosporidium , possibly because the subsample of cryptosporidium - positive stws was too small to detect an effect .
future studies examining water body contamination
and fecal pollution sources in similar settings should consider the
potential effects of fecal sources located outside defined study boundaries .
mapping in this analysis was limited to the point locations of local
pollution sources in odisha sanitation trial villages .
we were thus
unable to account for the possibility of unmapped villages having
open defecator households , latrine pits or cattlesheds within the
largest buffer distance ( 500 m ) considered around community water
sources .
this limitation is likely to mainly affect our analyses of
ponds , which were often located on the outskirts , rather than of tubewells ,
located within the village .
we also relied on self - report , which is
subject to recall bias , for estimating
usage rates and ages of latrines . repeated sampling of each water
source would have provided greater accuracy on protozoal prevalence
and concentration levels in each source and allowed for more fully
characterizing spatial and temporal variations in water source contamination
than was possible in our staggered cross - sectional study design .
however ,
because site visits for this study were randomized spatially across
a relatively homogeneous geographic study area and temporally within
the first 23 months of each monsoon season , and because study
villages were similar in terms of size , types of water and sanitation
infrastructure , ses characteristics , and economic activity , and all
samples were collected in the morning hours , we do not foresee significant
bias stemming from our single point sample design when used to estimate
area - level associations within the context of monsoon season contamination
patterns , as we have done here .
better information on soils ,
weather , and hydrogeology , such as groundwater recharge zones and
detailed lithology , would have allowed for better characterization
of protozoal transport into each tubewell or pond , but was not available
and beyond the scope of data collection for the odisha sanitation
trial . however , all study villages were within 50 km of each
other , and the geology of the study region is defined primarily as
a delta plane with predominant alluvium geological formation , reducing potential bias from these limitations .
we can not preclude
the possibility that cryptosporidium and giardia detected in a tubewell sample could have come from
a contaminated spout / mouth , however , we flushed each tubewell prior
to sample collection for 30 s and then rinsed each 2 l sample
bottle with tubewell water 3 times prior to filling to minimize this
possibility .
our village - level ses variables are imprecise and subject
to residual confounding from measurement error or miss - specification
of a category .
for example , beyond literacy status of the household
head , educational attainment level may have improved the association
between education status and water contamination .
finally , although
our conceptual model represents causal relationships grounded in scientific
literature , cross - sectional data and empirical modeling can only identify
correlations and our sample size may be under - powered to detect some
postulated associations .
these limitations must be kept in mind when
interpreting the associations we found between outcomes and predictor
variables .
further research
and better guidelines are needed to ensure the protection of critical
water sources used for drinking and to ensure household access to
microbiologically safe protozoa - free drinking water in rural india .
based on our findings , guidelines would include repairing damaged
deep tubewells to protect public groundwater drinking sources and
placing pour - flush latrine pits in india at distances > 15 m from
shallow
tubewells used for drinking .
however , these recommendations may be
ineffective in areas like this where water tables can rise within
2 m of ground - level and given the marginal evidence for and plausibility
of deeper groundwater contamination from latrine leaching densities
at greater distances .
alternatively , changing the below - ground design
of wet latrines may be needed to reduce or prevent leaching rates
and associated pathogen loads , but these increase sanitation costs .
in view of already widespread contamination of local water sources ,
anticipated rapid growth in latrine coverage , and difficulties achieving
high compliance and effective use of household water treatment , centrally treated and reliable piped water supplies with house connections | surface
and groundwater contamination with fecal pathogens is a
public health concern especially in low - income settings where these
sources are used untreated .
we modeled observed cryptosporidium and giardia contamination in community ponds ( n = 94 ; 79% contaminated ) , deep tubewells ( dtws ) ( n = 107 ; 17% ) , and shallow tubewells ( stws ) ( n = 96 ; 19% ) during the 2012 and 2013 monsoon seasons ( june august )
in 60 villages in puri district , india to understand sources and processes
of contamination . detection of cryptosporidium and/or giardia in a tubewell was positively associated with damage
to the well pad for dtws , the amount of human loading into pour - flush
latrine pits nearby ( 15 m ) for stws , and the village literacy
rate ( for giardia in stws ) . pond concentration levels
were positively associated with the number of people practicing open
defecation within 50 m and the sheep population for cryptosporidium , and with the village illiteracy rate for giardia .
recent rainfall increased the risk of cryptosporidium in stws ( an extreme event ) and ponds ( any ) , while increasing seasonal
rainfall decreased the risk of giardia in stws and
ponds . full latrine coverage in this setting
is expected to marginally
reduce pond cryptosporidium contamination ( 16% ) while
increasing local groundwater protozoal contamination ( 87306% ) ,
with the largest increases predicted for cryptosporidium in stws . |
the implant used for all patients was the esnoper - clip ( ajl ophthalmics , lava , spain ) , a new uveoscleral hema implant developed at the glaucoma unit of the hospital universitari germans trias i pujol , barcelona ( universitat autonoma of barcelona , spain ) .
it is a nonreabsorbable and foldable hema implant ( 2-hydroxyethyl methacrylate ) with 2 ft designed to maintain supraciliary and intrascleral spaces and to achieve higher intrascleral blebs ( fig .
the new foldable uveoscleral hema implant ( esnoper - clip ) designed and developed at the glaucoma unit of the hospital universitari germans trias i pujol , barcelona ( universitat autonoma of barcelona ) , spain .
this study , to evaluate the safety and effectiveness of esnoper - clip implants , involved a prospective analysis of 27 eyes from 27 patients with oag who underwent ds with an uveoscleral implant ( esnoper - clip ) implant between october 2011 and january 2013 followed up 1 year after surgery .
their surgical history included 16 uneventful phacoemulsifications , performed at least 6 months before surgery .
all patients were over 18 years of age and presented with uncontrollable primary or secondary oag iop ( 21 mm hg ) , or were under maximal tolerable medical treatment .
they signed the consent form approved by the department of ophthalmology of the hospital germans trias i pujol ( barcelona , spain ) and the study was conducted in accordance with the principles established in the declaration of helsinki and was approved by the institutional review board of the hospital germans trias i pujol ( barcelona , spain ) .
exclusion criteria were prior antiglaucoma surgery , or any other surgery which could have affected the conjunctiva in the region of the intervention , including cataract surgery 6 months before the present intervention , moderate or severe diabetic retinopathy , and other causes of ocular neovascularization .
we also excluded glaucoma patients with a high risk of failure , that is those presenting with neovascularization , aphakia , inflammation , juvenile cases , and cases of posttrauma and postsurgery glaucoma . in the preoperative assessment , patients underwent a complete examination including best - corrected visual acuity ( bcva ) on a decimal scale , biomicroscopy , goldmann tonometry , pachymetry ( up-1000 ; nidek , japan ) gonioscopy , fundoscopy , and the glaucoma therapy was recorded .
follow - up visits were scheduled at 24 hours , 1 , 3 , 6 , and 12 months after surgery , and included bcva , slit - lamp examination , tonometry , gonioscopy , and fundoscopy .
anterior segment optical coherence tomography ( as - oct ) ( visante oct ; carl zeiss meditec , jena , germany ) which provides an objective method to assess the anterior segment of the eye and the surgical area , was performed at months 1 , 3 , 6 , and 12 , to the intrascleral bleb height at 90 and 180 degrees and the highest was chosen . to determinate the volume of the intrascleral lake ,
we calculated its value from the height ( h ) , the vertical diameter or length ( l ) , and the horizontal diameter or width ( w ) using the formula volume=1/6hlw . as - oct measurements and analysis were performed by the same investigator ( j.c.m . ) .
a superior 4/0 nylon traction suture was passed through the superior cornea and a fornix - based conjunctival flap was dissected ( fig .
2a ) , followed by cauterization of bleeding vessels and dissection of the superficial scleral flap ( 55 mm ) of one third of the scleral depth , extending 2 mm into clear cornea . afterwards
, a mmc impregnated sheet was laid between the scleral flap and the remaining sclera as well as over the flap , and left there for 2 minutes and then irrigated thoroughly with balanced salt solution .
subsequently , a deeper 44 mm scleral flap was dissected and removed , and schlemm canal was deroofed with a capsulorhexis forceps .
the implant has 2 plates ; 1 was placed in a full - thickness suprachoroidal bag 2 mm behind the scleral spur , after the technique firstly described by muoz1 ( fig .
after folding the implant the other foot was placed into the intrascleral lake ( fig .
it can be fixed without suturing because it has 2 lateral notches that do not allow anterior displacement . to achieve higher intrascleral blebs ,
an intrascleral pocket was created at the posterior limit of the intrascleral bed to fix the posterior edge of the implant , thereby helping to keep the scleral lips apart ( fig .
no suture or a loose one , was used for the superficial scleral flap and the conjunctiva was sutured with a nylon 10/0 .
postoperative treatment consisted of topical ofloxacin ( exocin ; alcon cus sa , el masnou , barcelona , spain ) 4 times a day during 1 week and prednisolone acetate ( 10 mg / ml ) ( predforte ; allergan pharmaceuticals ireland , westport , ireland ) 6 times a day , the latter in a descending dosage over 6 weeks .
goniopuncture with the yag laser ( visulas yag iii combi ; carl zeiss meditec , dublin , ca ) was performed when percolation of aqueous humor was considered insufficient .
a , superficial scleral flap ( 55 mm ) of one third of the scleral depth , reaching 2 mm of clear cornea .
b , deep 44 mm scleral flap is dissected and removed , and schlemm canal was deroofed with a capsulorhexis forceps .
the implant has 2 plates ; one was placed in a full - thickness suprachoroidal bag 2 mm behind the scleral spur .
c , after folding the implant the other foot was placed into the intrascleral lake .
it can be fixed without suturing because it has 2 lateral notches that do not allow anterior displacement .
d , to achieve higher intrascleral blebs , an intrascleral pocket was created at the posterior limit of the intrascleral bed to fix the posterior edge of the implant , thereby helping to keep the scleral lips apart .
statistical analyses were performed using spss software for windows ( version 15.0 ; spss inc . ,
the differences in continuous variables before and after surgery were compared statistically using the nonparametric friedman test .
differences in presurgery iop values and those measured at each follow - up were analyzed using the wilcoxon matched - pairs signed - rank test .
this study , to evaluate the safety and effectiveness of esnoper - clip implants , involved a prospective analysis of 27 eyes from 27 patients with oag who underwent ds with an uveoscleral implant ( esnoper - clip ) implant between october 2011 and january 2013 followed up 1 year after surgery .
their surgical history included 16 uneventful phacoemulsifications , performed at least 6 months before surgery .
all patients were over 18 years of age and presented with uncontrollable primary or secondary oag iop ( 21 mm hg ) , or were under maximal tolerable medical treatment .
they signed the consent form approved by the department of ophthalmology of the hospital germans trias i pujol ( barcelona , spain ) and the study was conducted in accordance with the principles established in the declaration of helsinki and was approved by the institutional review board of the hospital germans trias i pujol ( barcelona , spain ) .
exclusion criteria were prior antiglaucoma surgery , or any other surgery which could have affected the conjunctiva in the region of the intervention , including cataract surgery 6 months before the present intervention , moderate or severe diabetic retinopathy , and other causes of ocular neovascularization .
we also excluded glaucoma patients with a high risk of failure , that is those presenting with neovascularization , aphakia , inflammation , juvenile cases , and cases of posttrauma and postsurgery glaucoma . in the preoperative assessment , patients underwent a complete examination including best - corrected visual acuity ( bcva ) on a decimal scale , biomicroscopy , goldmann tonometry , pachymetry ( up-1000 ; nidek , japan ) gonioscopy , fundoscopy , and the glaucoma therapy was recorded .
follow - up visits were scheduled at 24 hours , 1 , 3 , 6 , and 12 months after surgery , and included bcva , slit - lamp examination , tonometry , gonioscopy , and fundoscopy .
anterior segment optical coherence tomography ( as - oct ) ( visante oct ; carl zeiss meditec , jena , germany ) which provides an objective method to assess the anterior segment of the eye and the surgical area , was performed at months 1 , 3 , 6 , and 12 , to the intrascleral bleb height at 90 and 180 degrees and the highest was chosen . to determinate the volume of the intrascleral lake ,
we calculated its value from the height ( h ) , the vertical diameter or length ( l ) , and the horizontal diameter or width ( w ) using the formula volume=1/6hlw . as - oct measurements and analysis were performed by the same investigator ( j.c.m . ) .
a superior 4/0 nylon traction suture was passed through the superior cornea and a fornix - based conjunctival flap was dissected ( fig .
2a ) , followed by cauterization of bleeding vessels and dissection of the superficial scleral flap ( 55 mm ) of one third of the scleral depth , extending 2 mm into clear cornea . afterwards
, a mmc impregnated sheet was laid between the scleral flap and the remaining sclera as well as over the flap , and left there for 2 minutes and then irrigated thoroughly with balanced salt solution .
subsequently , a deeper 44 mm scleral flap was dissected and removed , and schlemm canal was deroofed with a capsulorhexis forceps .
the implant has 2 plates ; 1 was placed in a full - thickness suprachoroidal bag 2 mm behind the scleral spur , after the technique firstly described by muoz1 ( fig .
after folding the implant the other foot was placed into the intrascleral lake ( fig .
it can be fixed without suturing because it has 2 lateral notches that do not allow anterior displacement . to achieve higher intrascleral blebs
, an intrascleral pocket was created at the posterior limit of the intrascleral bed to fix the posterior edge of the implant , thereby helping to keep the scleral lips apart ( fig .
no suture or a loose one , was used for the superficial scleral flap and the conjunctiva was sutured with a nylon 10/0 .
postoperative treatment consisted of topical ofloxacin ( exocin ; alcon cus sa , el masnou , barcelona , spain ) 4 times a day during 1 week and prednisolone acetate ( 10 mg / ml ) ( predforte ; allergan pharmaceuticals ireland , westport , ireland ) 6 times a day , the latter in a descending dosage over 6 weeks .
goniopuncture with the yag laser ( visulas yag iii combi ; carl zeiss meditec , dublin , ca ) was performed when percolation of aqueous humor was considered insufficient .
a , superficial scleral flap ( 55 mm ) of one third of the scleral depth , reaching 2 mm of clear cornea .
b , deep 44 mm scleral flap is dissected and removed , and schlemm canal was deroofed with a capsulorhexis forceps .
the implant has 2 plates ; one was placed in a full - thickness suprachoroidal bag 2 mm behind the scleral spur .
c , after folding the implant the other foot was placed into the intrascleral lake .
it can be fixed without suturing because it has 2 lateral notches that do not allow anterior displacement .
d , to achieve higher intrascleral blebs , an intrascleral pocket was created at the posterior limit of the intrascleral bed to fix the posterior edge of the implant , thereby helping to keep the scleral lips apart .
statistical analyses were performed using spss software for windows ( version 15.0 ; spss inc . ,
the differences in continuous variables before and after surgery were compared statistically using the nonparametric friedman test .
differences in presurgery iop values and those measured at each follow - up were analyzed using the wilcoxon matched - pairs signed - rank test .
twelve months later , we found a statistically significant reduction in iop which had reached a mean of 15.35 mm hg ( p<0.001 ) .
there was also a statistically significant reduction in the number of medications after surgery , starting with a mean of 2.5 and arriving at 0.3 at the end of the study ( p<0.001 ) ( fig .
the most common type of glaucoma that was included in the study was primary open - angle glaucoma ( 88.9% of patients ) .
the mean volume and height of the intrascleral bleb 12 months after surgery were 3.91.3 mm and 0.70.1 mm , respectively ( fig .
3 ) . clinical and demographic characteristics of patients included in the study intraocular pressure evolution and numbers of medications a , mean changes in intraocular pressure ( iop ) and number of medications ( treatment ) .
the main postoperative complications were seidel at 24 hours in 2 eyes ( 7.4% ) , hyphema in 2 eyes ( 7.4% ) , choroidal detachment in 1 eye ( 3.7% ) , all of which resolved successfully and the need for additional mmc injections in 4 eyes ( 14.8% ) ( in 2 eyes , on 2 occasions ) .
twelve eyes ( 44.4% ) underwent postsurgical nd : yag goniopuncture ( nd : yag gp ) with a mean time between surgery and this procedure of 4.3 months .
complications related to goniopuncture were limited to choroidal detachment in 1 eye that resolved uneventfully . in this case , iop dropped from 20 to 2 mm hg .
the mean iop after nd : yag gp decreased from 19.2 to 15.5 mm hg ( p<0.001 ) .
ds with a supraciliary implant is an alternative that has been shown to be safe and effective with different types of implants.1,2 the main problem with this class of implants is that they are not specifically designed for this space , and so their effectiveness can be limited .
the intrascleral lake can lose height or even collapse over time and probably lose efficacy , because intrascleral bleb height plays an important role in lowering iop.35 in contrast , intrascleral implants do not facilitate uveoscleral outflow as well as supraciliary implants .
reports of supraciliary implantation are somewhat scarce and until now no studies with ultrasound biomicroscopy ( ubm ) or as - oct have been published .
muoz1 reported isolated ds and bonilla et al2 described phaco - ds resulting in iop reductions from 26.46.9 to 143.3 mm hg and 235 to 183 mm hg , respectively , after 1 year . in these series
, the number of medications was reduced from 2.8 to 0.3 and from 2.5 to 0.7 , respectively . in our series , iop decreased from 26.6 to 15.3 mm hg and the number of drugs to be taken was reduced from 2.5 to 0.26 at 12 months .
the incidence of complications is similar to that associated with intrascleral or supraciliary implantation described by other authors .
we can conclude that the present technique has no more additional complications for ds than other alternatives .
the importance and significance of the intrascleral and suprachoroidal spaces is a controversial issue , but currently it is widely accepted that both are good prognostic factors , but not the ones .
this controversy may be due to discrepancies in findings using as - oct or ubm .
ubm measurements have limited resolution and with as - oct , it is very difficult to determine the presence or absence of uveoscleral outflow .
mavrakanas et al3 and fernandez - buenaga et al4 using as - oct , perez - rico without impant and marchini et al5 using ubm reported a positive inverse correlation between postoperative iop and intrascleral bleb height .
mavrakanas et al3 only investigated eyes having ds with a collagen implant and postoperatively clinically flat blebs , whereas fernndez - buenaga et al4 investigated a heterogeneous group of eyes after ds using 3 different implants ( aquaflow , esnoper , sk - gel ) .
both authors found bleb heights between 0.58 and 0.65 mm , respectively , and found a significant correlation between height and iop with esnoper and aquaflow implants . here
, we have not studied the correlation between iop and intrascleral volume or height , but we did calculate the mean median bleb height ( 0.780.1 mm ) and volume ( 3.91.3 mm ) 12 months after operation .
these values in volume ( p=0.706 ) or height ( p=0.586 ) were not significantly different to those before operation .
another point to be considered is that the shape of our implant tries to keep the sclera lips apart , thereby facilitating transcleral outflow ( fig .
4 ) . this could decrease the height and volume of the intrascleral lake but in contrast , transcleral outflow represents a link between the intrascleral lake and the conjunctival filtering blebs and it had been found withubm6 to be a positive prognostic factor .
perez - rico et al5 using as - oct reported transcleral outflow to be a positive factor in 89.4% of eyes , 5 years after ds without implant .
the same author reported the association between lower iop and maximum anteroposterior length , height , and intrascleral volume .
anterior segment optical coherence tomography . the intrascleral lake and supraciliary space after the implantation with transcleral outflow ( arrows ) can be observed .
it had been published , in studies with ubm , as the tissue heals with scarring occupying the intrascleral lake6 over time in almost 10% of eyes with7 or without implants.8 using as - oct in eyes which have undergone ds without implant , the presence of the intrascleral lake had been revealed in 100% of the eyes after 5 years.5 discrepancies in these results are probably related to the trabeculo - descemet membrane ( tdm ) thickness and to the fact that if there is insufficient peeling of the inner wall of schlemm canal , enough outflow will not be achieved to maintain the intrascleral lake .
uveoscleral outflow in different series has a prevalence from 7% to 60%.9,10 however , these series are hardly comparable because they used different implants with varying follow - up times . using ubm7,11
it has been found that eyes with suprachoroidal filtration have lower iop than those without suprachoroidal filtration , whereas other authors8 could find no evidence of suprachoroidal filtration in any case , 1 year after surgery .
ravinet et al12 also found a similar rate of iop and postoperative treatments in eyes with or without hypoechoic areas after ds with t - flux and healon gv .
supraciliary implantation probably favors either a ciliary body detachment with subsequent decrease in aqueous production , or choroidal resorption leading to low postoperative iop .
although it seems logical to think that this could encourage late chronic ocular hypotony , there is no evidence of this in the literature or in the present series .
nevertheless , it should not be forgotten that young myopics are probably more likely to suffer from hypotony with supraciliary implantation .
this wide variation is likely due to the application of different criteria , implants , and iop targets .
the type of implant is likely a very significant factor in nd : yag gp as some implants may enhance more fibrosis over the tdm , or displacement above the tdm .
this new device which we report here has 2 lateral notches that prevent this from happening , and even in cases in which it does not remain fixed in the suprachoroidal bag , its shape does not collapse the tdm which remains always free without any filtration limitations . on the basis of the present findings , the uveoscleral implant ( esnoper - clip ) can be considered to be a promising alternative because it ensures the maintenance of both spaces helping to avoid collapse over time . further clinical trials with long - term follow - up and a larger numbers of patients will be needed to assess the effectiveness of this new uveoscleral implant , the morphology of the surgical area , the real relevance of the intrascleral lake characteristics , and their correlation with reduced iop . | purpose : to report the safety and the effectiveness of deep sclerectomy ( ds ) with a new nonabsorbable uveoscleral hema implant ( esnoper - clip ) designed to increase trabecular and uveoscleral outflow and to achieve higher intrascleral blebs.materials and methods : twenty - seven eyes of 27 patients with open - angle glaucoma , who underwent ds with an esnoper - clip implant , were included in this study .
all patients were followed up after 12 months.results:a significant decrease in intraocular pressure was observed after surgery , changing from a preoperative mean of 26.65.2 mm hg to a postoperative mean of 15.35 mm hg ( p<0.001 ) at 12 months .
there was also a significant reduction in the number of glaucoma drugs needed , varying from 2.5 per patient to 0.3 ( p<0.001 ) 1 year after surgery .
the main intrascleral lake height and volume at 12 months was 0.70.1 mm and 3.91.3 mm3 , respectively .
no intraoperative complications occurred .
the main postoperative complications were a positive seidel test result at 24 hours in 2 eyes ( 7.4% ) , hyphema in 2 eyes ( 7.4% ) , and choroidal detachment in 1 eye ( 3.7% ) .
all these complications resolved successfully . the need for additional mitomycin - c injections was recorded in 4 eyes ( 14.8% ) , twice in 2 of them .
twelve eyes ( 44.4% ) underwent postsurgical nd : yag laser goniopuncture with a mean time between surgery and this procedure of 4.3 months .
mean intraocular pressure after nd : yag laser goniopuncture decreased from 19.2 to 15.5 mm hg ( p<0.001).conclusion : ds with an uveoscleral hema implant ( esnoper - clip ) is a safe and effective technique for the management of open - angle glaucoma . |
the goal of glaucoma surgery is to reduce intraocular pressure , which decreases the likelihood and rate of visual field loss in susceptible patients.1 currently , there are a number of surgical options for reducing intraocular pressure in glaucoma that include incisional surgery , non - penetrating filtration surgery , glaucoma drainage devices , and minimally invasive glaucoma surgeries . the challenge of surgeries that require external fistulization is reactive scarring and abnormal wound healing of the subconjunctival space that lowers long - term success.2 numerous approaches have been used to prevent conjunctival fibrosis after filtering surgery .
currently , the cytotoxic antimetabolites , 5-fluorouracil and mitomycin c ( mmc ) , are the most commonly used agents.3 other agents that have been used to prevent postoperative scarring include anti - vascular endothelial growth factor antibodies,4 tumor growth factor beta antibodies,3 and ologen implants.5 however , these agents were either ineffective as yet , or there is limited evidence to suggest that they might replace mmc . despite many innovative approaches , mmc remains the most frequently used agent due to its reasonable efficacy in preventing subconjunctival fibrosis .
this review outlines the efficacy of various mmc preparations including the widely use concentration of 0.2 mg / ml of mmc prepared as an off - label product in a vial and a recently available kit , and compares it with other concentrations and exposure times of mmc .
cairns introduced trabeculectomy in 1968.6 over time , trabeculectomy has become the most common surgical procedure for glaucoma and is considered the gold standard for the surgical management of glaucoma .
a survey of the american and japanese glaucoma societies published in 1997 reported trabeculectomy was the preferred initial surgical approach for both societies.7 successful trabeculectomy requires a fistula that diverts aqueous humor into the subconjunctival space .
the main challenge postoperatively is to minimize scarring in the subconjunctival space by reducing inflammation and by slowing or halting the healing process .
long - term follow - up of primary trabeculectomy without adjunctive mmc indicates that despite successful control of intraocular pressure ( lop ) at 1 year , the probability of success decreases with time and stabilizes at 67% by 10 years.8 chen9 described the efficacy of mmc in enhancing bleb survival following trabeculectomy in eyes with a high risk of failure .
a 2004 survey of british ophthalmology consultants reported that 82% used antimetabolites during trabeculectomy.10 mmc was the most commonly used antimetabolite among american glaucoma society members in 2008.11 mmc was isolated in japan in 1954 from the broth of the streptomyces caespitosus .
its pharmacological effect is likely due to the quinone , carbamate , and aziridine groups that comprise the molecule .
mmc undergoes metabolic activation via reduction into an alkylating agent , a process mediated by cytochrome p-450 reductase and that occurs most effectively in a hypoxic environment.12 additionally , data available from the antitumor activity of mmc , including biochemical and cell - based experiments , demonstrate that the enzyme nqo1 can also bioactivate mmc and is generally a good predictor of mmc sensitivity.13 however , there are a host of factors that can influence the antitumor response to mmc that include intracellular ph and oxygen concentrations , competing bioreductive enzymes , and dna repair enzymes responsible for the repair of cytotoxic mmc - dna interstrand crosslinks .
hence , it is unlikely that studying only the nqo1 genotype or nqo1 protein levels will predict a mmc - related clinical response to tumor suppression or anti - fibrotic activity.13 in a study on human tenon s capsule tissue , mmc caused almost complete inhibition of fibroblast proliferation.14 however , many factors can influence the efficacy of mmc as it interacts with fibroblasts.14,15 these factors include the dose delivered to the tissues ( which is concentration dependent ) , volume , duration of exposure , preparation method , administration , and tissue - related factors.14 in vitro study of tenon s capsule cultures suggests that fibroblast inhibition due to mmc is mainly dependent on the concentration and that a sponge applied for 1 minute can be as effective as a sponge applied for 5 minutes.14,15 clinical studies have observed that tissue becomes saturated with mmc after exposure for 1 minute.16 additionally , control of iop was similar whether mmc was used for 2 minutes or 5 minutes.17,18 the effects of mmc concentration on the success of glaucoma surgery are discussed in this review .
flynn et al19 compared microsurgical sponges from alcon laboratories , inc ( fort worth , tx , usa ) , merocel ( medtronic , inc , dublin , leinster , uk ) , storz medical ag ( tuttlingen , germany ) , and weck - cel ( xomed surgical products , inc , jacksonville , fl , usa ) for mmc application .
they reported that the weck - cel brand demonstrated intermediate values for both the maximum volume absorbed and expansion widths of the sponge after the sponge was soaked in mmc .
these sponges also released the largest amount of mmc.19 the authors concluded that variability in drug delivery characteristics observed in vitro suggested that type of microsurgical sponge may be an important factor in mmc delivery to the tissues.19 another factor that might influence the efficacy of mmc is the area of tissue that comes in contact with mmc .
application of mmc over a larger surface area achieves a higher short - term decrease in iop and a significantly lower incidence of bleb scarring compared to eyes that receive mmc application over a smaller area.2022 the site and time of mmc application might also influence fibroblast inhibition .
traditionally , mmc has been applied into sub - tenon s space intraoperatively , with some surgeons also placing it beneath the scleral flap . applying mmc - soaked sponges before creating the scleral flap or beneath the scleral flap , and other variations in surgical technique , could influence the outcome of trabeculectomy beyond the influence of the concentration and duration of mmc application.23,24 furthermore , studies have suggested that intrascleral application of mmc might be as efficacious as subconjunctival application.2325 recently , mmc has been used as a single preoperative subconjunctival injection in various low - dose concentrations prior to trabeculectomy.26,27 though this technique appears to have gained popularity , there are no peer - reviewed publications that suggest that this method of application is superior to other techniques .
an additional factor that may play a role in lowering iop following application of mmc during trabeculectomy is mmc toxicity to the ciliary epithelium .
histopathological studies in human eyes and experimental studies have demonstrated toxic effects of mmc to the ciliary body and its epithelium , which likely cause a reduction in aqueous secretion and a lowering of iop.28,29 patient variables beyond those presented in this paper may influence surgical outcomes .
these include thickness of tenon s capsule , degree of tissue vascularity and bleeding , and possibly , different receptor responses to mmc.3 the adjunctive use of mmc has been a major advance in the efficacy of lowering iop with trabeculectomy . however , there are complications associated with mmc use , including hypotony and maculopathy in the early postoperative period .
many investigators have attempted to develop protocols for adjunctive therapy that allow an acceptable balance between the risks and benefits.911,18 a previous study has suggested that the level of inhibition of fibroblast proliferation correlated with the outcome of filtering surgery.30 a clinical trial has supported the benefit of mmc as an adjunct to trabeculectomy.31 an in vivo confocal microscopy study displayed that the final effect of the filtering procedure with mmc was a fivefold increase in conjunctival microcyst density and surface area on the site of the bleb.32 intraoperative treatments with mmc result in long term inhibition of fibroblast proliferation with abnormal marked variation in cell size and vacuoles in the cytoplasm limited to the treated area , when compared with intraoperative and postoperative treatment with 5-fu.33 a recent qualitative and quantitative analysis comparing filtering blebs with optical coherence tomography showed that blebs following mmc trabeculectomy had good functionality with low index of reflectivity and cystoid pattern . on the other hand , in trabeculectomies without mmc ,
mixed optical coherence tomography patterns ( layer or diffuse pattern ) were associated with high infrared and poor functionality.34 mmc can enhance the success rate of trabeculectomy for refractory glaucoma in patients of most ethnic backgrounds , including those of african ancestry.3542 enhanced success rates have also been reported in glaucoma associated with uveitis , congenital and developmental glaucoma , normal - tension glaucoma , and primary , uncomplicated trabeculectomies.3542 a cochrane database review of eleven clinical trials evaluating 698 patients concluded that mmc reduced the risk of surgical failure in eyes undergoing primary trabeculectomy and high - risk eyes.43 a study of primary trabeculectomy with low - dose mmc reported that iop was maintained at 15 mmhg or less in more than 80% of patients after 1 year and in 60% of patients after 6 years.44 a study with a majority of patients at high risk of failure reported that 0.2 mg / ml of mmc for 5 minutes resulted in an 84% success rate at 1 year follow - up.45 annen and strmer46 used 0.2 mg / ml mmc for 1 minute and noted an iop of < 21 mmhg in 88% of cases at approximately 1 year , with 8.8% of cases developing an avascular bleb . in a prospective , randomized study ,
kitazawa et al47 reported that 88% of glaucomatous eyes with poor surgical prognosis achieved an lop of 20 mmhg without glaucoma medications after mmc during trabeculectomy , while only 47% of eyes receiving 5-fluorouracil achieved a similar outcome in a period of 712 months .
similarly , skuta et als48 randomized study of eyes at high risk for failure from glaucoma filtering surgery reported that 60% of mmc - treated eyes had an iop of 12 mmhg versus only 21.1% of 5-fluorouracil - treated eyes at 6 months .
singh et al49 evaluated a consecutive series of 20 eyes that underwent trabeculectomy with 0.02 mg / ml mmc intraoperatively and reported an overall success rate of 85% . in this series , there were two cases of recurrent leaks and two cases of scleral necrosis exposing the ciliary body.49 the authors cautioned that such complications , though rare , can occur with lower doses of mmc , and they recommended that lower doses of mmc or placing mmc in the sub - tenon s space without scleral dissection could potentially avoid the complication of scleral necrosis .
furthermore , another study suggested that based on the successful outcome of trabeculectomy with mmc , its use may be justified in primary trabeculectomies in patients with advanced glaucoma.44 in pediatric patients who underwent trabeculectomy with mmc , the success rates varied from 56% to 95%.5052 additionally , administration of mmc during filtering surgery often leads to development of thin - walled , avascular blebs , which might result in bleb leaks that predispose eyes to infection.53,54 there may be an increased risk of developing a thin - walled bleb with higher concentrations of mmc.55 high - dose mmc can be associated with complications .
akova et al56 reported two cases of scleromalacia in pediatric patients who received 0.4 mg / cc mmc for 5 minutes .
fourman57 reported a case series of five patients who developed scleritis 3 to 24 weeks after adjunctive mmc during inferior trabeculectomy .
mmc has also been used with success as an adjunct to needling and non - penetrating glaucoma surgery . using mmc during needling
a failed filtering bleb resulted in an 85% success rate.58 in a retrospective study , mardelli et al59 reported that mmc needle revision is an effective method to revive failed filtration surgery in terms of iop reduction .
trials have also shown that intraoperative mmc during deep sclerectomy results in lower iops.60,61 however , mmc in glaucoma drainage devices does not seem to affect the outcome of the surgical procedure during molteno valve62,63 or ahmed glaucoma valve implantation.64,65 based on the literature and our current review , it appears that reducing mmc dosage or exposure time of intraoperative mmc may mitigate the incidence of complications associated with overfiltration and perhaps , may also avoid the development of ischemic blebs .
cairns introduced trabeculectomy in 1968.6 over time , trabeculectomy has become the most common surgical procedure for glaucoma and is considered the gold standard for the surgical management of glaucoma .
a survey of the american and japanese glaucoma societies published in 1997 reported trabeculectomy was the preferred initial surgical approach for both societies.7 successful trabeculectomy requires a fistula that diverts aqueous humor into the subconjunctival space .
the main challenge postoperatively is to minimize scarring in the subconjunctival space by reducing inflammation and by slowing or halting the healing process .
long - term follow - up of primary trabeculectomy without adjunctive mmc indicates that despite successful control of intraocular pressure ( lop ) at 1 year , the probability of success decreases with time and stabilizes at 67% by 10 years.8 chen9 described the efficacy of mmc in enhancing bleb survival following trabeculectomy in eyes with a high risk of failure .
a 2004 survey of british ophthalmology consultants reported that 82% used antimetabolites during trabeculectomy.10 mmc was the most commonly used antimetabolite among american glaucoma society members in 2008.11
its pharmacological effect is likely due to the quinone , carbamate , and aziridine groups that comprise the molecule .
mmc undergoes metabolic activation via reduction into an alkylating agent , a process mediated by cytochrome p-450 reductase and that occurs most effectively in a hypoxic environment.12 additionally , data available from the antitumor activity of mmc , including biochemical and cell - based experiments , demonstrate that the enzyme nqo1 can also bioactivate mmc and is generally a good predictor of mmc sensitivity.13 however , there are a host of factors that can influence the antitumor response to mmc that include intracellular ph and oxygen concentrations , competing bioreductive enzymes , and dna repair enzymes responsible for the repair of cytotoxic mmc - dna interstrand crosslinks . hence , it is unlikely that studying only the nqo1 genotype or nqo1 protein levels will predict a mmc - related clinical response to tumor suppression or anti - fibrotic activity.13 in a study on human tenon s capsule tissue , mmc caused almost complete inhibition of fibroblast proliferation.14 however , many factors can influence the efficacy of mmc as it interacts with fibroblasts.14,15 these factors include the dose delivered to the tissues ( which is concentration dependent ) , volume , duration of exposure , preparation method , administration , and tissue - related factors.14 in vitro study of tenon s capsule cultures suggests that fibroblast inhibition due to mmc is mainly dependent on the concentration and that a sponge applied for 1 minute can be as effective as a sponge applied for 5 minutes.14,15 clinical studies have observed that tissue becomes saturated with mmc after exposure for 1 minute.16 additionally , control of iop was similar whether mmc was used for 2 minutes or 5 minutes.17,18 the effects of mmc concentration on the success of glaucoma surgery are discussed in this review .
flynn et al19 compared microsurgical sponges from alcon laboratories , inc ( fort worth , tx , usa ) , merocel ( medtronic , inc , dublin , leinster , uk ) , storz medical ag ( tuttlingen , germany ) , and weck - cel ( xomed surgical products , inc , jacksonville , fl , usa ) for mmc application .
they reported that the weck - cel brand demonstrated intermediate values for both the maximum volume absorbed and expansion widths of the sponge after the sponge was soaked in mmc .
these sponges also released the largest amount of mmc.19 the authors concluded that variability in drug delivery characteristics observed in vitro suggested that type of microsurgical sponge may be an important factor in mmc delivery to the tissues.19 another factor that might influence the efficacy of mmc is the area of tissue that comes in contact with mmc .
application of mmc over a larger surface area achieves a higher short - term decrease in iop and a significantly lower incidence of bleb scarring compared to eyes that receive mmc application over a smaller area.2022 the site and time of mmc application might also influence fibroblast inhibition .
traditionally , mmc has been applied into sub - tenon s space intraoperatively , with some surgeons also placing it beneath the scleral flap . applying mmc - soaked sponges before creating the scleral flap or beneath the scleral flap , and other variations in surgical technique ,
could influence the outcome of trabeculectomy beyond the influence of the concentration and duration of mmc application.23,24 furthermore , studies have suggested that intrascleral application of mmc might be as efficacious as subconjunctival application.2325 recently , mmc has been used as a single preoperative subconjunctival injection in various low - dose concentrations prior to trabeculectomy.26,27 though this technique appears to have gained popularity , there are no peer - reviewed publications that suggest that this method of application is superior to other techniques .
an additional factor that may play a role in lowering iop following application of mmc during trabeculectomy is mmc toxicity to the ciliary epithelium .
histopathological studies in human eyes and experimental studies have demonstrated toxic effects of mmc to the ciliary body and its epithelium , which likely cause a reduction in aqueous secretion and a lowering of iop.28,29 patient variables beyond those presented in this paper may influence surgical outcomes .
these include thickness of tenon s capsule , degree of tissue vascularity and bleeding , and possibly , different receptor responses to mmc.3
the adjunctive use of mmc has been a major advance in the efficacy of lowering iop with trabeculectomy . however , there are complications associated with mmc use , including hypotony and maculopathy in the early postoperative period .
many investigators have attempted to develop protocols for adjunctive therapy that allow an acceptable balance between the risks and benefits.911,18 a previous study has suggested that the level of inhibition of fibroblast proliferation correlated with the outcome of filtering surgery.30 a clinical trial has supported the benefit of mmc as an adjunct to trabeculectomy.31 an in vivo confocal microscopy study displayed that the final effect of the filtering procedure with mmc was a fivefold increase in conjunctival microcyst density and surface area on the site of the bleb.32 intraoperative treatments with mmc result in long term inhibition of fibroblast proliferation with abnormal marked variation in cell size and vacuoles in the cytoplasm limited to the treated area , when compared with intraoperative and postoperative treatment with 5-fu.33 a recent qualitative and quantitative analysis comparing filtering blebs with optical coherence tomography showed that blebs following mmc trabeculectomy had good functionality with low index of reflectivity and cystoid pattern . on the other hand , in trabeculectomies without mmc , mixed optical coherence tomography patterns ( layer or diffuse pattern ) were associated with high infrared and poor functionality.34 mmc can enhance the success rate of trabeculectomy for refractory glaucoma in patients of most ethnic backgrounds , including those of african ancestry.3542 enhanced success rates have also been reported in glaucoma associated with uveitis , congenital and developmental glaucoma , normal - tension glaucoma , and primary , uncomplicated trabeculectomies.3542 a cochrane database review of eleven clinical trials evaluating 698 patients concluded that mmc reduced the risk of surgical failure in eyes undergoing primary trabeculectomy and high - risk eyes.43 a study of primary trabeculectomy with low - dose mmc reported that iop was maintained at 15 mmhg or less in more than 80% of patients after 1 year and in 60% of patients after 6 years.44 a study with a majority of patients at high risk of failure reported that 0.2 mg / ml of mmc for 5 minutes resulted in an 84% success rate at 1 year follow - up.45 annen and strmer46 used 0.2 mg / ml mmc for 1 minute and noted an iop of < 21 mmhg in 88% of cases at approximately 1 year , with 8.8% of cases developing an avascular bleb . in a prospective , randomized study ,
kitazawa et al47 reported that 88% of glaucomatous eyes with poor surgical prognosis achieved an lop of 20 mmhg without glaucoma medications after mmc during trabeculectomy , while only 47% of eyes receiving 5-fluorouracil achieved a similar outcome in a period of 712 months .
similarly , skuta et als48 randomized study of eyes at high risk for failure from glaucoma filtering surgery reported that 60% of mmc - treated eyes had an iop of 12 mmhg versus only 21.1% of 5-fluorouracil - treated eyes at 6 months .
singh et al49 evaluated a consecutive series of 20 eyes that underwent trabeculectomy with 0.02 mg / ml mmc intraoperatively and reported an overall success rate of 85% . in this series , there were two cases of recurrent leaks and two cases of scleral necrosis exposing the ciliary body.49 the authors cautioned that such complications , though rare , can occur with lower doses of mmc , and they recommended that lower doses of mmc or placing mmc in the sub - tenon s space without scleral dissection could potentially avoid the complication of scleral necrosis .
furthermore , another study suggested that based on the successful outcome of trabeculectomy with mmc , its use may be justified in primary trabeculectomies in patients with advanced glaucoma.44 in pediatric patients who underwent trabeculectomy with mmc , the success rates varied from 56% to 95%.5052 additionally , administration of mmc during filtering surgery often leads to development of thin - walled , avascular blebs , which might result in bleb leaks that predispose eyes to infection.53,54 there may be an increased risk of developing a thin - walled bleb with higher concentrations of mmc.55 high - dose mmc can be associated with complications .
akova et al56 reported two cases of scleromalacia in pediatric patients who received 0.4 mg / cc mmc for 5 minutes .
fourman57 reported a case series of five patients who developed scleritis 3 to 24 weeks after adjunctive mmc during inferior trabeculectomy .
mmc has also been used with success as an adjunct to needling and non - penetrating glaucoma surgery . using mmc during needling
a failed filtering bleb resulted in an 85% success rate.58 in a retrospective study , mardelli et al59 reported that mmc needle revision is an effective method to revive failed filtration surgery in terms of iop reduction .
trials have also shown that intraoperative mmc during deep sclerectomy results in lower iops.60,61 however , mmc in glaucoma drainage devices does not seem to affect the outcome of the surgical procedure during molteno valve62,63 or ahmed glaucoma valve implantation.64,65 based on the literature and our current review , it appears that reducing mmc dosage or exposure time of intraoperative mmc may mitigate the incidence of complications associated with overfiltration and perhaps , may also avoid the development of ischemic blebs .
prospective and retrospective studies have addressed the effectiveness of various concentrations of mmc on the outcome of glaucoma filtration surgery .
however , the conclusions regarding effects of mmc concentration and exposure time are variable , and these observations are summarized in this section ( later ) .
robin et al66 evaluated four groups : placebo , 0.2 mg / ml mmc for 2 minutes , 0.2 mg / ml mmc for 4 minutes , and 0.4 mg / ml mmc for 2 minutes , respectively , with 1-year follow - up .
response relationship exists between efficacy and the concentration and duration of exposure to mmc.66 kitazawa et al67 evaluated 0.02 and 0.2 mg / ml mmc in primary trabeculectomy and reported 63.6% and 100% success rates , respectively , with transient hypotony maculopathy ( 18% ) and cataract progression ( 18% ) noted in the 0.2 mg / ml group exclusively .
the authors suggested that the appropriate dose was between the two concentrations.67 laube et al68 evaluated 0.1 , 0.2 , and 0.4 mg / ml of mmc for 2.5 minutes , and found that 0.2 mg / ml was the most effective dose .
alternately , other studies have reported that altering the exposure time had little to no effect on postoperative iop reduction or success rates of trabeculectomy.17,18 sanders et al69 confirmed that filtering surgery performed on higher risk eyes was as effective at a lower dose ( 0.2 mg / ml ) of mmc compared to a higher dose ( 0.4 mg / ml ) .
they reported a higher incidence of hypotony - related complications with the higher concentration ( 0.4 mg / ml ) group.69 maquet et al70 used three different concentrations of mmc ( 0.1 mg / ml , 0.2 mg / ml , and 0.4 mg / ml ) and found no significant differences in iop control and postoperative complications .
lee et al71 compared 0.4 mg / ml , 0.2 mg / ml , and 0.1 mg / ml mmc in 36 eyes and found no statistical difference in iop reduction between concentrations .
they noted postoperative hypotony in only two patients , both from the 0.4 mg / ml group.71 a recent prospective , randomized trial with 2 years follow - up demonstrated the non - inferiority of 0.1 mg / ml of mmc compared to 0.2 mg / ml.72 the use of mmc in pediatric glaucoma has also been studied .
agarwal et al73 reported that mmc 0.4 mg / ml and 0.2 mg / ml were equally effective in post - trabeculectomy patients with congenital glaucoma .
they also reported that 0.2 mg / ml mmc resulted in a lower incidence of thin - walled blebs , postoperative hypotony , wound leakage , and choroidal detachments.73 most studies of prolonged mmc application report an increased risk of postoperative complications.16,74,75 however , this observation remains controversial.18 a retrospective , comparative study on patients at high risk for failure reported that surgical success at 18 months postoperatively with 0.2 mg / ml mmc for 2 minutes was similar to a matched group receiving 0.2 mg / ml mmc for 5 minutes.18 in combined trabeculectomy with phacoemulsification and intraocular lens implantation with mmc 0.5 mg / ml applications of 1 , 3 , or 5 minutes , the iop outcomes were similar.76 in addition to the benefits of lowering iop , mmc - assisted trabeculectomy may have an impact on the patient s quality of life ( qol ) .
the collaborative initial glaucoma treatment study ( cigts ) compared the outcome of medical treatment to initial mmc trabeculectomy.77 at 5 years follow - up , both medical and surgical therapy were effective in reducing iop , but initial surgery led to lower visual field progression in subjects with advanced visual field loss at baseline.77 however , the risk of cataract formation after trabeculectomy was higher , resulting in a decrease in vision - related qol.77 most , but not all , vision qol subscales indicated worsening of cataracts prior to cataract surgery and an improvement in vision after cataract extraction.78 a french study reported that poor vision - related qol was associated with topical drug side effects.79 a recent report on quality - adjusted life - years and the incremental cost - effectiveness ratio reported that glaucoma surgeries such as trabeculectomy and tube insertion were determined to be cost - effective compared with medical therapy alone , and that trabeculectomy had a lower cost per quality - adjusted life - year compared with tube insertion.80 though the cost effectiveness of trabeculectomy has been addressed in studies discussed earlier , the direct and indirect costs associated with a failed trabeculectomy and its comparison with a primary trabeculectomy with mitosol ( mobius therapeutics , llc , st louis , mo , usa ) remain unknown .
future studies are likely to address this issue . in summary , most studies appear to suggest that lower concentrations of mmc and shorter exposure times are as effective in achieving lower iops when compared to higher concentrations / prolonged exposure times .
in contrast , higher mmc concentrations and prolonged exposure times may be associated with a higher risk of complications .
some variability in the study outcomes related to mmc concentration and exposure time might be dependent on study design , patient selection , and outcome measures .
mmc is customarily frozen in storage and thawed to room temperature before use or prepared on site from a vial .
the use of different concentrations of mmc requires on - site preparation under suboptimal conditions and can lead to dosage errors.81 the potency of mmc after storage has been studied in vitro.82 high - performance liquid chromatography evaluation indicated that mmc had similar stability , despite different preparations and storage methods , if it was used immediately upon reaching room temperature.83 however , some degradation of mmc occurred with further storage at room temperature , and the clinical effects of this degradation are unclear.83 additionally , on - site formulation can result in an unstable solution , due to incorrect ph or storage temperatures.84 the off - label application of mmc in glaucoma surgery has been quite effective .
however , many variables may affect the stability and efficacy of mmc when prepared on site compared to a compounding pharmacy .
recently , the us food and drug administration ( fda ) approved mmc for ab externo glaucoma surgery .
the preparation is available in a 0.2 mg / vial concentration , with standardized sponges packaged in a kit ( mitosol ) .
the advantages of this kit include reliable potency prepared in optimal conditions , proper dosing , sterility , and an extended shelf life at room temperature .
additionally , standardized sponges are included in the kit as the size , type , and shape of the sponge might influence the efficacy of mmc.19,85 a standard number of sponges are included to eliminate human error when counting used sponges during surgery .
fda approval was based on the efficacy of mmc in open - angle glaucoma reported in the existing body of literature.86 the availability of a standardized preparation of mmc is a welcome addition in the armamentarium of adjunctive therapy in glaucoma filtration surgery .
however , there are some controversial aspects to the introduction of this preparation . for example
, there have been no randomized clinical trials comparing the mitosol kit to mmc prepared in a compounding pharmacy .
however , higher concentrations of mmc may be preferred for cases of repeat trabeculectomy or inflammatory glaucoma.70 furthermore , this preparation may not be available in developing countries .
the most controversial aspect of this preparation is the substantial increase in the cost of the surgical procedure .
the cost of one mitosol kit is reportedly us$359 , which is several - fold more expensive than the off - label preparation of mmc ( depending on the country).86 this issue is similar to the debate on the cost - effectiveness of ophthalmic bevacizumab versus ranibizumab in the treatment of retinal disease.87
standardization of different variables during trabeculectomy has been investigated for several years and has been discussed in detail in this review .
the efficacy of 0.2 mg / ml of mmc applied for a period of 23 minutes during surgery appears to be quite effective in clinical trials . however , prospective studies are warranted to determine the efficacy of standardized preparations of mmc , such as mitosol .
standardized kits such as mitosol are likely to result in faster surgery while mitigating dosage errors , maintaining aseptic conditions , and preventing other intraoperative errors , such as retained sponges .
the issue of cost of standardized preparations needs to be addressed , especially if the goal is worldwide distribution . | the success of trabeculectomy , which is considered the gold standard in the surgical treatment of glaucoma , depends on the wound healing response .
the introduction of antiproliferative agents such as mitomycin c ( mmc ) has increased the success rates of trabeculectomy .
however , complications due to these agents can be challenging to manage . hence , it is important to determine the most efficacious dose and duration of exposure .
multiple studies suggest that many factors , including but not limited to mmc preparation , different concentrations , different exposure times , and method of application may affect success rate , and these factors were reviewed in this article .
we concluded that lower concentrations of mmc that are prepared and applied in a standardized fashion , such as that using the mitosol kit ( for 23 minutes ) during trabeculectomy , could potentially provide trabeculectomy success rates similar to that reported with off - label preparations , and that such a treatment regime could result in in lower complication rates than higher doses of mmc . |
nowadays , the african region still faces the wors health conditions in comparison with the rest of the world .
thirty - two african countries are among the world 's forty - eight least developed nations while literature reports that the 90% of the eleven million of children ( up to 5 years age ) dying every year for neonatal disorders , diarrhea , acute respiratory infections and malaria are found in the poorest counties worldwide .
poverty , underdevelopment and un - nourishment together with wars , drought , lack of health and educational services are some of the more relevant health determinants in the region . since common risk factors , such as social , economic , and political ones ,
are worldwide recognized both for some of the most common noncommunicable diseases and oral diseases , awareness is generally rising about the need to integrate general health action plans with oral health interventions .
dental caries and periodontal disease prevalence seems not to be so severe in africa as in the rest of the world while oral disease pattern is not homogeneous across the region and need to be assessed in each community . in 2006 , thorpe highlighted the importance of having reliable data about the oral health profile of different communities across africa as a prerequisite to develop and improve effective intervention programmes to address oral health needs .
the major challenges for the near future will be to turn knowledge and experience of disease prevention into action .
clear disparities widened the gap between poor and rich countries . in may 2007 , the who general assembly ( wha60.17 resolution ) claimed for considering mechanism to provide coverage of the population with essential oral health care to promote the availability of oral health services that should be directed towards diseases prevention and health promotion for poor and disadvantage , countries .
for these countries it is needed to consider , especially for schoolchildren , the development and implementation of preventive programmes , as a part of activities in health promoting schools , aiming to introduce healthy lifestyle and self - care practices in children [ 6 , 7 ] .
burkina faso , previously known as upper volta , is a low - income country in west africa having 50% of the population living with less then 1 us$ per day , characterized by poor sanitary conditions and lack of services . in burkina faso , as well as in other african countries , a national oral health system is developing , and health promotion and oral disease prevention are the main goals health authorities are promoting . in order to plan community oral health promotion programmes ,
although the dmft is reported to be rather low ( 0.7 at 12 years old and 1.9 at 18 years ) , periodontal diseases are extensively diffused and oral manifestation of aids , gangrenous infections ( anug ) and noma still represents a serious concern [ 4 , 9 ] .
the oudalan province is one of the 45 provinces of burkina faso , located in the northern part of burkina faso , and it is included within sahel , the semi - arid belt running across sub - saharan africa .
oudalan is divided into 5 departments : deou , gorom - gorom , markoye , oursi and tin - akof .
almost 400 kilometers far from ouagadougou , burkina faso capital city , there is the municipality of gorom gorom , a small town surrounded by tens of villages and gatherings in the savannah .
no current oral health services are available both for town and villages inhabitants and the first available dental clinic is 60 kilometres faraway . consequently in oudalan province , the population has a poor or lack access to dental care .
people suffer with tooth pain , often with no opportunity for relief , without making a long and costly journey .
dental visits are mainly performed for symptomatic reasons and not for restorative reasons . in order to set up the needs for intervention and to plan oral health prevention and care programmes
, this paper aims to describe the epidemiological oral health status and behaviour in children living in the municipality of gorom - gorom , oudalan province , sahel region , burkina faso .
this survey included the most relevant subgroups of the population ( always 12 years age included ) according to the world health organization .
the survey was carried out as a cross - sectional study , during two months , in 2008 in children living in the municipality of gorom gorom , oudalan province , sahel region , burkina faso ( figure 1 ) .
the municipality counts about 80,000 inhabitants living in 82 villages and in gorom gorom capital .
the fluoride concentration was carried out using an orion model 96.09 fluoride ion selective electrode and an orion model 900200 double junction plastic body ag / cl reference electrode with orion model 290 mv digital meter .
fluoride content was quite high , with a mean value of 1.7 0.6 ppm .
no direct previous contact had been with a dental worker before for the children population , but traditional healer serves for people oral care needs .
children aged 5 - 6 and 12 years from 11 schools and 9 villages of the municipality were included in the survey .
the 5 - 6 year group is relevant for the examination of deciduous teeth while the 12 year for the permanent ones .
an authorization for the survey was obtained both from national health , educational authorities and local administrators . during a school meeting ,
parents or guardians were informed about the aim of the survey , describing the dental visit procedure and explaining the questionnaire items ; after all , their verbal agreement was obtained .
all children 's parents or guardians consented to clinical examination and oral interview . in schools
the collection was conducted in the presence of teachers and in rural villages in the presence of the local chief .
the sample size was 692 children ; 334 females ( 48.3% ) and 358 males ( 51.7% ) .
the subjects were then categorized for age into two groups : 338 subjects aged 5 - 6 years ( 48.8% ) and 354 subjects aged 12 years ( 51.2% ) .
when it was not possible , due to the lack of data collection ( i.e. remote villages and gatherings ) , children with a deciduous full - arch were considered 5 years old , those with first permanent molars not yet fully erupted ( under occlusal edge ) 6 years old , those with second permanent molars not completely yet erupted 12 years old .
the month before the beginning of the study , the examiner took part to a calibration session organized in the who collaboration centre of milan .
forty subjects ( 20 for each age group ) were re - examined after 72 hours by the examiner .
the visits were performed on a simple bed or school table using a plain mirror , a who - cpi probe , paper hand towels , and gauzes to remove debris from around the teeth .
the instruments were first washed in a conventional manner with soap and then sterilized with a solution of paracetic acid ( parasafe ) . an artificial head - light source was used .
the examination setting was always arranged according to the local condition and avoiding natural light sources and crowding .
general information about the patient like age , gender , ethnic group , and living conditions was collected .
the recorded clinical conditions were dental caries experience ( dmft / dmft ) , gingival condition ( presence of plaque and/or calculus ) , and fluorosis following who indication .
dental caries was registered when decay at the dentinal lesion level was found ; gingival conditions were scored into three classes following the community periodontal index : score 0 ( healthy ) , score 1 ( gingival bleeding at probing ) , and score 2 ( calculus ) .
cleanliness of the hands was recorded as follows : score 1 ( clean ) , score 2 ( dirty ) and score 3 ( crusted ) as a proxy of hygiene condition of the subject .
oral health related behaviours were collected by a questionnaire directed to children and parents or guardians .
it was divided into different items : oral hygiene habits ( tooth - brushing habit , use of a toothbrush or a chewing stick , use of fluoridated toothpaste ) and dietary habits ( number of meal per diem ) .
caries distribution according to age was calculated as mean standard errors ( se ) .
caries prevalence was calculated as the number of subjects with dt > 0 and dmft > 0 compared to the whole sample .
odds ratio ( or ) was calculated between caries prevalence and other variables ( age , gender , fluorosis , and cleanliness of hands ) as well as for periodontal condition ( with gender , caries experience , cleanliness of hands , and oral hygiene habit ) .
no score for missing or filled tooth was assigned , so data reported only caries activity ( dt ) prevalence . in the two age groups ( 5 - 6 and 12 years ) , dt ( mean se ) was 1.5 0.1 and 0.1 0.3 , while dt ( mean se ) was 0.2 0.3 and 0.5 0.6 .
table 1 describes the entire caries experience by age , gender , fluorosis , and cleanliness of hands as count ( percent ) and odds ratio ( or ) for each category . according to dean 's index ,
61 children ( 8.8% ) showed no sign of fluorosis or it was uncertain ; for 343 children ( 49.7% ) it was very mild , for 213 ( 30.9% ) it was mild , for 72 ( 10.4% ) it was moderate or severe ( table 2 ) .
overall , 37.9% ( 150 of 5 - 6 years and 112 of 12 years ) of children showed healthy gingival condition .
plaque was scored in 27.8% of cases ( 107 of 5 - 6 years and 85 of 12 years ) , while calculus in 34.4% of cases ( 81 of 5 - 6 years and 157 of 12 years ) .
children reported having 3 meals per day in 97.1% of the sample ( 672 ) and 2 meals per day in 2.9% ( 20 children ) .
children were reported to brush their teeth in 35.7% ( 247 ) of the sample : 7.1% ( 49 children ) with a toothbrush and 28.6% ( 198 children ) with a chewing stick .
table 3 shows an association between community periodontal index scores and toothbrushing habit and chewing stick usage , respectively .
no association was found between cpi scores and gender , caries experience and cleanliness of hands , respectively ( p > .05 ) ( data not in table ) . significant trends in proportion ( p < .05 ) of community periodontal index , across categories of exposure , were found for these two variables .
nowadays , the usual etiologic approach to tooth decay or periodontal disease is revised considering social , cultural , environmental determinants as well as oral health systems orientation .
many more other studies have been carried out on oral health determinants and today oral pathology is considered a social exclusion pointer .
oral health is today an unfulfilled need for most people worldwide especially for those belonging to the most disadvantaged groups of society both in low and high income countries .
the burden of oral disease is growing due to a lack of proper community oral health programmes .
the evidence for a link between sociobehavioural risk factors and dental decay was pointed out , underlining a social gradient in caries prevalence [ 14 , 15 ] .
this model highlights three distal determinants for oral health : health systems and oral health services , sociocultural risk factors and environmental risk factors .
the aim of this study was to provide an overview of the oral health condition of children in the region of burkina faso in order to assist an intervention of oral health promotion .
few epidemiological data are available for oral health condition in burkina faso as a whole ; the latest ones date back to the 90s and reported general poor oral health hygiene , significant prevalence of periodontal diseases , and generally low prevalence of dental decays ( with higher levels in urban areas ) .
no specific data for the oudalan province was found at the moment of this survey nor conducted and no previous contact has had been with a dental worker for the children population .
this situation points out the urgent need to implement integrated primary oral health care and oral health services that meet the needs of the local population as suggested by who 's global strategies .
the main finding of this study was the low caries prevalence ( more than three quarters of the children were without obvious caries caries free ) probably linked to the quite high concentration of fluoride in well water .
similarly , the high fluoride concentration is the cause of the high level of fluorosis observed . the absence of filled or missing for caries scored teeth ( m / f score ) highlights the absence of accessible services even for urgent treatments . comparing with other data collected in southwest burkina faso in 1999
, scoring caries prevalence at 38% of 6 year - aged children , this study reports a very lower rate .
the majority of children resulted to have 3 meals per day : diet is not varied , poor in quantity , and low in calories .
the most common food is a milk soup , millet , and sugar , badly affecting their growth .
cariogenic snacks are not available except for a minority of children living in gorom gorom , while it is a common habit to drink sweet herb brew .
only a few children from gorom gorom reported to use a fluoridated toothpaste due to a lack of availability as well as for general high cost , as reported in literature [ 18 , 19 ] .
the use of a toothbrush is quite common in town , while it is almost absent in villages .
a common habit of the population is to use a chewing stick from acacia tree ; a statistically significant association has been found between periodontal condition and chewing habit .
no clear significance was found between periodontal condition and cleanliness of hands , while it was found for caries experience .
less than fifty percent of children have clean hands considering that drought and lack of water are common .
moreover , this survey was conducted during the dry season when highly severe diseases as acute and chronic intestinal infections spread and put life of children at serious risk .
the present study maybe the typical limitation of a cross - sectional survey , like the low number of participants with respect to total population .
. however , in this report the rate of participants was high and this is the first report about children oral condition living in this area . from a public health point of view
this study supports recommendation from the most authoritative international organizations claiming the urgent need to change policies and strategies for oral health . in may 2007 ,
the assembly of the world health organisation declared that the economic burden of oral diseases is expected to rise rapidly globally , above all , among disadvantaged and poor population groups , at least until programmes for the prevention of oral disease are promoted . moreover , as reported by the lancet in 2009 , training more dentists and building dental clinics
the western curative model of care is costly and unrealistic in most low - income and middle - income countries .
primary health care approach ( basic and sustainable care , community participation , appropriate technology , maternal and childhood health focus and prevention integrated with educational and social sectors ) is the only realistic one to address oral health needs for communities at any latitude of the world .
a good first step to improve the oral condition of the oudalan children should be that local authorities would accept and organize a dental service based on basic package of oral care ( bpoc ) developed by the who collaborating centre of nijmegen .
although it is recognised that communities and the circumstances in which african populations live are widely different , to win the many challenges ahead for africa , it is important to build up strategies to provide equitable and universal access to oral health care services and to promote preventive oral health programs in order to significantly reduce the impact of oral diseases in african populations . | aim . in order to set up the needs for intervention and to plan oral health prevention and care programmes , this paper aims to describe the oral health status and behaviour in children living in the municipality of gorom - gorom , burkina faso .
design .
the sample size was 692 children , 334 females ( 48.3% ) and 358 males ( 51.7% ) .
clinical and oral health related behaviours were collected .
results .
83.4% of the children were caries - free .
fluorosis was recorded in 41.3% of the sample , while only 37.9% of children showed healthy gingival condition .
toothbrushing was reported by 35.7% of children .
a statistically significant association was found between caries experience and cleanliness of hands .
community periodontal index was statistically associated to toothbrushing and chewingstick use . conclusion . as suggested by who 's global strategies , integrated primary oral health care and services meeting the dental needs of the local population are necessary for children living in this area of africa . |
raynaud phenomenon is a common health problem characterized by episodic cyanosis , swelling , and pallor on both upper and lower extremities with cold exposure .
this group of disorders predominantly affects females . in the history of this disorder , researches have described many etiologic factors , but , to date , neither an objective , quantitative diagnostic tool , nor an objective follow - up method has been defined . in this study
, we aimed to find an optimized method for the follow - up of patients with raynaud phenomenon .
in this retrospective study , we aimed to describe an optimized method for the follow - up of patients with raynaud phenomenon , and to compare its efficacy with a verbal complaint severity scale .
our local ethics committee approved the study ( ethics approval number 1291 ) . between august 2012 and july 2013 ,
data of 81 patients with raynaud phenomenon symptomatology were collected . systemic evaluation including blood examinations , capillaroscopy , and doppler ultrasonography
demographic data , concomitant disorders ( such as hypertension , diabetes mellitus , renal insufficiency , and thoracic outlet syndromes ) , and type and duration of symptoms were recorded . in our center ,
therefore , we routinely apply the cold stimulation test ( cst ) to all of our patients presenting with the raynaud phenomenon symptomatology .
all patients are only allowed to wear their shirts , without additional jackets or coats throughout the test .
all measurements of cst are performed with the patient s hand at the level of the heart . a sonatemp 400/700 monitor ( sheridan catheter corp .
hand temperatures of the patients are measured with a probe , which is inserted between the pulp of the first and second distal phalanges .
the most affected extremity is immersed into the + 4c iced - water for 20 seconds .
, the fingertip temperature is measured again at 5 , 10 , 15 and 20 minutes , with the same technique as detailed before .
the assessment scale for cst is given in table 1 . in order to evaluate the effectiveness of the medical treatment , we routinely use a verbal complaint severity scale ( vcss ) described in our previous study . according to our clinical protocol
, we routinely use the combination of pentoxifylline 1200 mg / d bid ( 2600 mg ) as a vasodilator molecule , nifedipine 60 mg / d bid ( 230 mg ) as a calcium - channel blocker , and acetylsalicylic acid 300 mg / d ( 1300 mg ) as an antiplatelet agent . beside these medications ,
all of the patients are advised to protect themselves from cold as much as possible .
spss for mac 20.0 package program ( spss inc , chicago , il ) was used for statistical evaluation .
descriptive results were expressed as mean standard deviation for normally distributed continuous variables and median values for abnormally distributed continuous variables .
comparisons of the parametric values were performed with the t - test for normally distributed groups and with mann - whitney u test and wilcoxon signed ranks test with abnormally distributed groups .
pearson s chi - square test , fisher s exact test , and mcnemar - bowker test were used for the comparisons of categorical variables . a p value of < 0.05 was considered as statistically significant with a 95% confidence interval .
between august 2012 and july 2013 , data of 81 patients with raynaud phenomenon symptomatology were collected . systemic evaluation including blood examinations , capillaroscopy , and doppler ultrasonography
demographic data , concomitant disorders ( such as hypertension , diabetes mellitus , renal insufficiency , and thoracic outlet syndromes ) , and type and duration of symptoms were recorded .
in our center , testing of patients response to cold stimulation is mandatory due to our national regulations .
therefore , we routinely apply the cold stimulation test ( cst ) to all of our patients presenting with the raynaud phenomenon symptomatology .
all patients are only allowed to wear their shirts , without additional jackets or coats throughout the test .
all measurements of cst are performed with the patient s hand at the level of the heart .
hand temperatures of the patients are measured with a probe , which is inserted between the pulp of the first and second distal phalanges .
the most affected extremity is immersed into the + 4c iced - water for 20 seconds .
the fingertip temperature is measured again at 5 , 10 , 15 and 20 minutes , with the same technique as detailed before .
we recently defined an assessment scale of cst in our previous paper . the assessment scale for cst
is given in table 1 . in order to evaluate the effectiveness of the medical treatment
, we routinely use a verbal complaint severity scale ( vcss ) described in our previous study .
according to our clinical protocol , we routinely use the combination of pentoxifylline 1200 mg / d bid ( 2600 mg ) as a vasodilator molecule , nifedipine 60 mg / d bid ( 230 mg ) as a calcium - channel blocker , and acetylsalicylic acid 300 mg / d ( 1300 mg ) as an antiplatelet agent . beside these medications ,
all of the patients are advised to protect themselves from cold as much as possible .
spss for mac 20.0 package program ( spss inc , chicago , il ) was used for statistical evaluation .
descriptive results were expressed as mean standard deviation for normally distributed continuous variables and median values for abnormally distributed continuous variables .
comparisons of the parametric values were performed with the t - test for normally distributed groups and with mann - whitney u test and wilcoxon signed ranks test with abnormally distributed groups .
pearson s chi - square test , fisher s exact test , and mcnemar - bowker test were used for the comparisons of categorical variables . a p value of < 0.05 was considered as statistically significant with a 95% confidence interval .
since this study was performed in a military hospital , all of the patients were young males ; 56 out of 81 patients ( 69.1% ) are heavy smokers ( 17 patients > 10 years ) .
cold - aggravated cyanosis ( 66 patients , 81.4% ) , coldness ( 50 patients , 61.7% ) , and numbness ( 47 patients , 58% ) were the most frequent symptoms .
the other complaints were as following : hyperhidrosis ( 45 patients , 55.5% ) , cold aggravated swelling ( 32 patients , 39.5% ) , burning sensation ( 19 patients , 23.4% ) and pain ( 9 patients , 11.1% ) ; 57 of patients ( 70.1% ) had 3 or more complaints mentioned before , while only 1 patient had all complaints above .
11 patients were in vcss i , 32 patients were in vcss ii , and 38 patients were in vcss iii .
after the treatment , when those patients were questioned again , there were no statistically significant differences between before and after treatment vcss . however , 4 patients changed their scores after the treatment .
one patient in vcss i declared as vcss ii and 3 patients in vcss iii declared as vcss ii .
there was a significant decrease in hand temperatures after cold exposure in both pre - treatment and post - treatment periods .
pre - treatment parabola appeared to have a concave curve , which means that the temperature increased gradually .
post - treatment parabola appeared like a convex curve , which means that temperature increased quickly , and continued almost at this level .
there were statistically significant differences between pre - treatment and post - treatment hand temperatures at each measurement ( p<0.001 ) except initial values ( p>0.05 ) .
when the results of cst for every measurement time point were separately analyzed , the following results were found : at 5 minute measurements , there was 4.02.9c increase when compared to pre - treatment values ( p<0.001 ) . at 10 minute measurements
, there was 6.93.1c increase when compared to pre - treatment values ( p<0.001 ) . at 15 minute measurements ,
there was 5.93.4c increase when compared to pre - treatment values ( p<0.001 ) . at 20 minute measurements
, there was 3.23.3c increase when compared to pre - treatment values ( p<0.001 ) .
in addition , there was a 7.24.4 minutes decrease in rewarming time to initial temperature at post - treatment period compared with pre - treatment values , which was also statistically significant ( p<0.001 ) .
a comparison of rewarming times at pre - treatment and post - treatment periods is given in table 4 .
according to assessment scale of cst results , the distribution of included patients in the present study is given in table 5 .
since this study was performed in a military hospital , all of the patients were young males ; 56 out of 81 patients ( 69.1% ) are heavy smokers ( 17 patients > 10 years ) .
cold - aggravated cyanosis ( 66 patients , 81.4% ) , coldness ( 50 patients , 61.7% ) , and numbness ( 47 patients , 58% ) were the most frequent symptoms .
the other complaints were as following : hyperhidrosis ( 45 patients , 55.5% ) , cold aggravated swelling ( 32 patients , 39.5% ) , burning sensation ( 19 patients , 23.4% ) and pain ( 9 patients , 11.1% ) ; 57 of patients ( 70.1% ) had 3 or more complaints mentioned before , while only 1 patient had all complaints above .
11 patients were in vcss i , 32 patients were in vcss ii , and 38 patients were in vcss iii .
after the treatment , when those patients were questioned again , there were no statistically significant differences between before and after treatment vcss . however , 4 patients changed their scores after the treatment .
one patient in vcss i declared as vcss ii and 3 patients in vcss iii declared as vcss ii .
there was a significant decrease in hand temperatures after cold exposure in both pre - treatment and post - treatment periods .
pre - treatment parabola appeared to have a concave curve , which means that the temperature increased gradually .
post - treatment parabola appeared like a convex curve , which means that temperature increased quickly , and continued almost at this level .
there were statistically significant differences between pre - treatment and post - treatment hand temperatures at each measurement ( p<0.001 ) except initial values ( p>0.05 ) .
when the results of cst for every measurement time point were separately analyzed , the following results were found : at 5 minute measurements , there was 4.02.9c increase when compared to pre - treatment values ( p<0.001 ) . at 10 minute measurements
, there was 6.93.1c increase when compared to pre - treatment values ( p<0.001 ) . at 15 minute measurements
, there was 5.93.4c increase when compared to pre - treatment values ( p<0.001 ) . at 20 minute measurements
, there was 3.23.3c increase when compared to pre - treatment values ( p<0.001 ) .
in addition , there was a 7.24.4 minutes decrease in rewarming time to initial temperature at post - treatment period compared with pre - treatment values , which was also statistically significant ( p<0.001 ) .
a comparison of rewarming times at pre - treatment and post - treatment periods is given in table 4 . according to assessment scale of cst results ,
since the first description of raynaud phenomenon , several diagnostic tools and treatment methods have been used .
however , neither a definitive diagnostic tool nor an obvious curative treatment method has been defined , primarily due to the complex etiopathogenesis , which is still not understood completely
. the second cause of this diagnostic problem may be the subjectivity of patients symptoms .
most rp patients complain about cyanosis and numbness , which is often aggravated with cold exposure .
these symptoms are quite inadequate for definitive diagnosis , but secondary forms of this disorder , mostly based on an underlying disease , can be diagnosed with more objective tests . in this respect ,
several diagnostic tools for definitive diagnosis have been defined : observation of triphasic color changes of hands and fingers , measurement of finger systolic blood pressure or finger - brachial index , plethysmography , capillaroscopy , doppler ultrasonography , and , rarely , more invasive techniques such as arteriography .
most of these tools require special conditions , such as special technicians , devices , and sometimes laboratory conditions .
however , even though they could be performed once for diagnosis , none of them could be used for follow - up , because of the above - mentioned features .
in addition to these problems , assessment of treatment efficacy in the follow - up period is the other important problem , which also mainly depends on subjectivity of patients and their symptoms .
most patients consider that all treatment modalities , independent of their types , are ineffective .
however , if we could find a user - friendly , objective test to follow up these patients , we can evaluate their progress and document it ; then we can convince the patients about the progress of their status . in our study
we used verbal complaint severity scale ( vcss ) for patient self - expressed feelings , such as their ideas about the treatment efficacy and the progress of the disease ; 11 patients were categorized in vcss i at pre - treatment and 10 patients were categorized in vcss i after treatment .
thus , it seems that 1 of these 11 patients probably thought that their complaint became worse in the follow - up period .
however , 3 patients in vcss iii before treatment were categorized in vcss ii after treatment , which probably means that their symptoms improved with treatment , but none of these changes were statistically significant and none were quantitative , obvious , and re - measurable . in this
regard , cst seems to be helpful for quantitative and objective follow - up of patients with rp . in our study
the quantitative data of cst such as temperature changes and decreases in rewarming time were statistically significant .
when we analyzed these parameters of cst , besides the accuracy of our test , we also observed variable patterns of rewarming and rewarming time . following a decrease in hand temperature after the cold stimulation , we observed significant differences in rewarming patterns between the 2 groups ( figure 1 ) .
the concave curve of pre - treatment figures in the rewarming period shows that the temperature increases slowly at the beginning , then there was a gradually increase in rewarming rate , which suggests that vasospasm lasts longer .
in contrast , the convex curve of post - treatment figures in the rewarming period shows that the temperature increased quickly at the beginning , and then reached initial temperature slowly , which suggests that vasospasm duration was shorter than in the former period .
when our results were analyzed and compared objectively , there were 2 parameters that can be used for follow - up of patients .
one of them is patients verbal complaint severity scale and the other is the result of cst .
we analyzed data from the 4 patients who had changed their verbal complaint severity scale after treatment as a subgroup , and we compared their cst results independent from the study group . in paired correlations , we found that there were no statistically significant differences between measured temperatures or rewarming times before and after treatment ( p>0.05 ) .
we also found that there were no statistically significant differences in the other remaining patients who considered that no improvement was observed within the treatment protocol ( p>0.05 ) .
these results mean that if the follow - up period assessment depends only on patients expression , researchers would have to reach a conclusion about treatment ( positive or negative ) ; however , these results would be far from real conclusions .
, the cold stimulation test can be used as an objective and quantitative test , especially for follow - up of patients under treatment when it is performed with certain criteria like in our study .
second , although the patients have expressed that there is no change after treatment , the study results revealed that the treatment were objectively effective .
although more extensive studies are necessary , based on our results , we conclude that cst with certain criteria seems to be a much more objective , quantitative , easy to use , and scientific method than
patients self - expression for follow - up of patients with rp , regardless of treatment methods .
this study was performed in a military hospital ; therefore , all of the patients were male .
for this reason , it may be difficult to make a generalized conclusion for both sexes from these results .
this study was performed in a military hospital ; therefore , all of the patients were male .
for this reason , it may be difficult to make a generalized conclusion for both sexes from these results . | backgroundraynaud phenomenon ( rp ) is common worldwide and presents diagnostic and therapeutic difficulties .
we aimed to share our experience with optimizing of patient follow - up by using the cold - stimulation test ( cst).material / methodsdata of 81 patients admitted with rp symptomatology were collected .
demographic data and symptoms were recorded .
a scale was used for determining the severity of disease at pre - treatment and post - treatment .
cst was performed to all patients at pre - treatment and post - treatment for assessment of treatment efficiency in follow - up .
results were analyzed with the spss for mac 20.0 program.resultsall the patients were male .
mean age was 22.32.14 ( 1929 ) .
mean duration of symptoms from onset to present was 4.592.85 years .
there were statistically significant differences between pre - treatment and post - treatment hand temperatures measured by cst ( p<0.001 ) .
however , there were no statistically significant differences between pre - treatment and post - treatment severity scores of patients ( p=0.135).conclusionsto quantitatively determine the treatment efficacy , cst may be used instead of asking simple questions of patients . |
-thalassemias ( thal ) are inherited defects in the rate of synthesis of globin chains of hemoglobin , that are widely distributed throughout the world , with considerable frequencies in the eastern mediterranean countries , including iraq [ 13 ] .
the two most northern provinces of iraq are dohuk and erbil which cover together an area of around 20 000 square kilometers ( figure 1 ) , bordering iran and turkey , with a population of around 2.2 million of mostly ethnic kurds .
thalassemia major is an important problem in these two provinces as well as other parts of the country , with more than 700 registered transfusion - dependent patients in the only two thalassemia centers in the two provinces .
the huge burden imposed on the health authorities and on the patients and their families mandates that a proper preventive program is established in this region .
an earlier smaller paper has looked at the molecular basis of this disease among carriers in one province , while the current study was designed to look at its basis among transfusion dependent thalassemics , with the aim of establishing an integrated prenatal program covering these two provinces .
a total of 127 unrelated transfusion dependent -thal patients , registered at the erbil ( 74 cases ) and dohuk ( 53 cases ) thal care centers , northern iraq , were recruited .
the patients were all ethnic kurds , with ages ranging between 1 and 38 years ( median age of 9 years ) .
informed consent was obtained from all subjects , and the study was approved by the research councils of colleges of medicine , hawler medical university , and dohuk university , iraq .
a 5 ml sample was aspirated by venipuncture from each subject , anticoagulated in edta , frozen and then at the appropriate time had its dna extracted by a chloroform - phenol - based method .
the dna was amplified in a multiplex reaction mixture , followed by hybridization to specific wild and mutant oligoprobes designed to detect 20 -thal mutations which are encountered in mediterranean countries ( vienna labordiagnostica gmbh , vienna , austria ) .
the -thal mutations screened for , included : 87 ( cg ) ; 30 ( ta ) ; codon 5 ( ct ) ; codon 6 ( a ) ; codon 8 ( aa ) ; codon 8/9 ( + g ) ; codon 22 ( 7 bp ) ; codon 30 ( gc ) ; ivs - i-1 ( ga ) ; ivs - i-2 ( ta ) ; ivs - i-5 ( gc ) ; ivs - i-6 ( tc ) ; ivs - i-110 ( ga ) ; ivs - i-116 ( tg ) ; ivs - i ( 25 ) ; codon 36/37(t ) ; codon 39 ( ct ) ; codon 44 ( c ) ; ivs - ii-1 ( ga ) ; and ivs - ii-745 ( cg ) . the amplification , hybridization , and detection procedures were performed as recommended by the manufacturer .
the seven most frequent ones constituted 88.2% of all thal defects . these mutations in order of frequency were ivs - ii-1 ( 73 chromosomes : 28.7% ) , ivs - i-1 ( 45 chromosomes : 17.7% ) , codon 8 ( aa ) ( 23 chromosomes : 9.1% ) , codon 8/9 ( 23 chromosomes : 9.1% ) , codon 39 ( 23 chromosomes : 9.1% ) , codon 44 ( 21 chromosomes , 8.3% ) , and codon 5 ( 16 chromosomes : 6.3% ) .
another seven mutations were less frequent or sporadic including ivs - i-6 , ivs - i-5 , ivs - i-110 , codon 36/37 , codon 30 , codon 22 , and ivs - ii-745 ( table 1 ) .
none of the studied chromosomes had the 30 ( ta ) , 87 ( cg ) , ivs - i-2 ( ta ) , ivs - i-25 ( 25 bp del ) , ivs - i-116 ( tg ) , or codon 6 ( a ) mutations .
-thal defects remained uncharacterized in 10 chromosome ( 3.9% ) . among the 127 patients ,
the most frequent mutation among homozygous patients was ivs - ii-1 followed by ivs - i-1 .
the most frequent compound heterozygous state was ivs - ii-1/ivs - i-1 followed by ivs - i-1/codon 8/9 . it was observed that while ivs - ii-1 is the predominant mutation in both provinces , there were notable differences in distribution of other common mutants .
erbil province contributed the larger proportion of ivs - i-1 ( 34/45 ) , codon 8 ( 19/23 ) and codon 8/9 ( 15/23 ) , while dohuk contributed most cases of codon 44 ( 19/21 ) and codon 39 ( 16/23 ) ( table 1 ) .
this study included transfusion dependent thal major patients from two provincial thal centers covering a population of more than two millions in northern iraq .
the latter population includes mainly ethnic kurds , whose history suggests that they have migrated to this region through iran more than 2500 years ago .
thus , it would not be unexpected that the ivs - ii-1 mutation is the most frequent mutation identified in our patients , since almost all iranian studies report the latter mutation as the most frequent one , particularly those performed in northwestern iran and among iranian kurds [ 68 ] .
such high rates of ivsii-1 are not shared by kurds of diyarbakir in southeastern turkey or any other of iraq neighboring states , except for eastern saudi arabia and kuwait [ 10 , 11 ] , which supports the notion that latter rates may also be attributable to gene flow from neighboring iran .
the higher frequency of ivs - ii-1 in iran , compared to its neighbors has led some investigators to speculate that this mutation may have originated or have undergone more efficient selection there .
the other most common mutations identified in the current study , were ivs - i-1 and codon 8 , both mediterranean mutations .
the frequencies for both latter mutations were among the highest reported in the eastern mediterranean region [ 4 , 615 ] .
moreover , the majority of chromosomes carrying the latter two mutations were from erbil , indicating further regional variations even within the same ethnic group ( iraqi kurds ) .
codon 8/9 ( + g ) is an asian indian mutation , which is common in the indian subcontinent as well as northwestern iran and in iranian kurds ( 14.5% and 15.7% , resp . ) [ 7 , 8 ] . this mutation is among the common mutation in the current study and more so in erbil nearer to iran .
its frequency apparently decreases as we move west and north to dohuk province and east anatolia region of turkey ( 5.1% ) .
the mutation is less common , sporadic , or absent in other surrounding eastern mediterranean countries [ 1015 ] .
codon 8/9 presence in our region maybe related to trade along the ancient silk road which passed through this part of northern iraq .
codon 39 is a mediterranean mutation which is common mainly in the western mediterranean , and its frequency decreases as we move to the east except for high frequencies in saudi arabia and bahrain , and its high frequency among our patients particularly those from dohuk is not quite expected , as it is not shared by the kurds of southeastern turkey or western iran at 2.8% and 1.7% , respectively [ 8 , 9 ] .
codon 5 , on the other hand , which has been considered a kurdish / iranian mutation was reported in significant proportion of cases in an earlier study from dohuk , as well as iranian kurds , but not from east anatolia region of turkey .
it is interesting to note that codon 44 , which has been labeled as a kurdish mutation , was only sporadically reported in erbil , and the majority of cases came from dohuk province .
this is consistent with a study on jewish kurds originating from dohuk region and with an earlier study on thal carriers from dohuk which reported it as the second most frequent mutation [ 4 , 16 ] .
this further emphasizes the regional variation in mutation distribution among kurds and supports the notion that the latter mutation maybe of recent origin , originating in the dohuk region , probably in the last 2000 + years , following the kurdish settlement in the region .
another kurdish mutation , codon 36/37 reported among the lurs of western iran as well as jewish and iranian kurds [ 8 , 16 , 17 ] , was found in homozygous state in only one patient from erbil in the current study , but not from dohuk .
similarly , this mutation was only sporadic in east anatolia region of turkey bordering the two iraqi provinces .
another important observation is that in contrast to many other eastern mediterranean populations , where the ivs - i-110 is the predominant mutation [ 9 , 1215 ] , it was only seen in 2.1% of our cases , a figure which is much lower than the 27.8% , 18% and 6% reported , respectively , from southeastern turkey , northwestern and kurdish iranians [ 79 ] .
this mutation has its highest frequencies in cyprus , but its frequency gradually decreases in countries further to the east , with a distribution pattern almost opposite to that of ivs - ii-1 [ 10 , 11 , 14 , 15 , 18 ] .
it maybe argued that the high consanguinity rate among homozygous individuals may have affected the actual frequencies of some of the mutations in the current study , however , even if this is taken into account , the most frequent seven mutations will remain so , and will not thus affect the overall prenatal diagnostic program in the region .
this study on iraqi kurds from northern iraq , revealed some similarities to studies from iranian kurds living across the border in iran , which consistent with the common origin of these populations .
however some notable difference in the frequencies of some particular mutations between these two population and within the iraqi kurds are likely to be due either to recent origin of such mutations or to various selective advantages ( such as malaria ) which may have had different impacts on the rates observed .
such observations further stress the need to screen other areas and ethnic groups in the country , to ensure establishing an effective prenatal diagnostic program . | molecular defects responsible for -thalassemias ( thal ) were investigated among 254 chromosomes from 127 transfusion - dependent unrelated thalassemic patients from two provinces in northern iraq . among
fourteen identified mutations , the seven most common found in 88.2% of the thal chromosomes were : ivs - ii-1 ( g a ) , ivs - i-1 ( g a ) , codon 8 ( aa ) , codon 39 ( g t ) , codon 8/9 ( + g ) , codon 44 ( c ) , and codon 5 ( ct ) .
there were some notable differences in frequencies of various mutations in comparison to other eastern mediterranean populations , as well as between the two provinces studied .
the latter illustrates the relative heterogeneity of the mutations distribution in iraq , and the need to screen other areas of the country , to ensure establishing an effective prenatal program . |
cystic adventitial degeneration ( cad ) is a rare disease but a serious claudication that causes vascular stenosis , usually in middle - aged men.1,2 in ~85% of cases reported , cad affects the popliteal artery.1,2 typically , duplex sonography , angiography , contrast - enhanced computed tomography , and magnetic resonance imaging ( mri ) are used to establish a diagnosis.3,4 earlier studies on cad are almost single case reports or small case series.3,4 as little is known about intra - vascular ultrasound ( ivus ) findings and their importance in patients with cad , we report here our experience of a case in which ivus correctly identified cad of the popliteal artery when angiography was inconclusive .
an 87-year - old male was referred to our hospital with a com - plaint of intermittent claudication in the left calf with a walking distance of about 100 m. his coronary risk factors were hypertension , diabetes mellitus , dyslipidemia , and chronic kidney disease ( estimated glomerular filtration rate 51 ml / minute/1.73 m ) .
there was no cyanosis of the left lower limb , no ulceration , and no dystrophic signs .
he had no history of connective tissue disease , which was also excluded by physical and laboratory examinations .
his ankle - brachial index ( abi ) was 0.92 on the right leg and 0.46 on the left leg . ,
as shown in figure 1 , digital subtraction angiography ( dsa ) of the left lower extremity showed that the left popliteal artery had a severe eccentric stenosis .
attempt to pass the stenotic site by a 0.014 inch chevalier floppy wire ( future medical design corporation ) was performed , and the guide wire was easily crossed .
ivus ( viewit ; terumo corporation ) revealed a nonatherosclerotic lesion and cystic appearance ; the area of extravascular hypodensity was clearly visualized , which was causing extrinsic compression of the lumen ( fig .
2 ) . because we considered a differential diagnosis , including cyst , tumor , and cad by these ivus findings , we stopped endovascular therapy and performed mri .
the axial view of mri revealed cystic lesions encompassing the left popliteal artery circumferentially ( fig .
, these cystic lesions also exhibited high signal intensity on t2-weighted images clearly ( fig .
because of the characteristic location and clinical signs , we diagnosed cad of the popliteal artery . thus , we considered that ivus may be used as an adjunctive tool to diagnose and evaluate cad when angiography was inconclusive .
the segment was resected , and an interposition graft was completed with a segment of reversed saphenous vein .
histopathologic analysis of the segment demonstrated myxoid change with formation of cystic spaces , primarily involving the adventitia ( fig .
spinner et al.5 recently reported the joint connection of the middle genicular artery in patients with cad , that is , the conduit for cyst propagation from the knee joint to the parent vessel .
however , in our case , a joint connection was not identified on mri or at operation .
the follow - up abi was normalized , and clinical success with symptom resolution was achieved .
here , we report a rare case in which ivus finding was useful for diagnosis and evaluation of cad of the popliteal artery . although stenotic lesions in lower extremities arteries are mostly caused by arteriosclerosis obliterans , nonatherosclerotic causes such as popliteal artery entrapment syndrome , cad , and thrombosed aneurysm must be considered in lesions of the popliteal artery as this case .
atkins and key6 first reported cad of the iliac artery in 1947 and hiertonn and lindberg7 first described cad of the popliteal artery in 1957 .
ishibashi et al.8 reported age and sex distribution of cad : males ( 83.2% ) and average age 44.6 years .
most of the patients with cad are less than 50 years of age in general , and case reports of patients older than 80 years are uncommon , with only two cases .
thus , it was difficult to diagnose in our case because the patient was of advanced old age ( 87 years ) .
several hypotheses have been put forward : microtraumatic origin , repeated stretch injuries causing degeneration of the arterial adventitia,9 embryologic origin , embryological displacement of mucin - secreting cells into the adventitia of the artery from endothelium of the knee joint,10 and ganglion formation ; cyst is a true ganglion of the vessel wall.11 treatment of cad typically consists of complete surgical resection of the diseased arterial segment with reversed saphenous vein graft interposition.4 because of both the high incidence of recurrence and the risk of dissection or rupture , percutaneous transluminal angioplasty and needle aspiration were ineffective.12 thus , we decided to treat by resection and autovein grafting because of the lowest recurrence rate .
typically , duplex sonography , angiography , and mri are used to establish a diagnosis.3,4 body surface sonography is useful for identifying the cyst and diagnostic imaging of cad .
unfortunately , the specificity of duplex sonography is dependent on the skill of the technician .
although ivus is an invasive imaging device , ivus finding might be one of the adjunctive tools as our case .
ivus excluded atherosclerosis , hematoma , aneurysm , and dissection and clearly identified the extravascular cyst that compressed the lumen in real time ( fig .
cad is a rare disease ; thus , ivus findings might provide unique diagnostic clues in patients with cad and be one of the useful and feasible methods for evaluating cad .
although uncommon , cad should be considered as a potential cause of intermittent claudication by the lesion of the popliteal artery . our report raises the possibility that diagnosis of cad supported by ivus device is suitable . | an 87-year - old male was admitted with intermittent claudication of the left calf .
we performed lower extremity angiography , which revealed stenosis of the left popliteal artery .
intravascular ultrasound ( ivus ) image correctly identified the cystic appearance of visualized extravascular hypodensity , causing extrinsic compression of the lumen .
we diagnosed the condition as cystic adventitial degeneration ( cad ) of the popliteal artery .
we operated a resection of a cyst with the artery and replaced the autovein graft ( saphenous vein ) .
after surgery , the patient was free of symptoms .
cad is a rare disease ; thus , our ivus findings may provide unique diagnostic clues in patients with cad . |
crohn s disease ( cd ) is a chronic inflammatory disease of the digestive tract of unknown etiology .
are common features , and nutritional deficiencies occur in cd patients in both active and remission phases .
emaciation is found in 2075% of patients with cd [ 1 , 2 ] , and approximately 75% of hospitalized cd patients are undernourished [ 3 , 4 ] .
malnutrition in cd patients is associated with decreased dietary intake , malabsorption , and protein - losing enteropathy .
furthermore , micronutrient deficiencies including vitamin d , vitamin b12 , folic acid , zinc and selenium are frequent in these patients [ 58 ] .
nutritional support is essential for cd patients , and nutritional therapy such as enteral nutrition ( en ) or total parenteral nutrition ( tpn ) has been established as primary therapy for cd as well as infliximab therapy and steroid therapy . especially , elemental diet therapies are effective in both induction and maintenance therapies [ 911 ] , although their therapeutic mechanisms are still unknown .
. however , melchior et al . reported that measured ree ( mree ) was approximately 33 kcal / kg / day in patients with cd , which was lower than the ree observed in other diseases .
furthermore , schneeweiss et al . reported that mree was not significantly different between cd patients and healthy subjects .
in japan , nutritional therapies such as en or tpn therapies are widely accepted , but energy metabolism in japanese patients with cd remains unclear .
total energy of en or tpn is usually determined by using predicted resting energy expenditure ( pree ) calculated by the harris - benedict equation , and total energy requirements are calculated by pree active factor stress factor . on the other hand , mree can be determined by indirect calorimetry .
theoretically , pree is equal to mree in healthy humans , and mree / pbee ratios are markers of hyper - metabolic status . in this study
, we evaluated energy metabolism in japanese patients with cd and suggested optimal energy requirements for nutritional therapies .
sixteen patients with cd ( 5 women and 11 men , median age 36 years old ) and 8 healthy volunteers were enrolled in this study .
all patients had the diagnosis of cd established by radiological , histological , and clinical criteria . among these patients , two patients had colitic disease , six patients had ileal disease and eight patients had ileocolitic disease .
infliximab therapy has just been started in four patients , and ( oral ) prednisone ( 1030 mg / day ) was taken by five patients .
mrees and respiratory quotients ( rq ) were measured by computed open - circuit indirect calorimetery ( ae-300s ; minato medical science co. , osaka , japan ) .
indirect calorimetry ( ic ) was performed in the hospital room the morning after a 10-h overnight fasting , but infusion of total parenteral nutrition solution were kept on going .
period flow and gas calibration were performed prior to measurements . after resting for a minimum of 30 min ,
after equilibrium was reached for 10 min , respiratory exchange was performed continuously over 30 min .
mree was calculated from oxygen consumption ( vo2 ) and carbon dioxide production ( vco2 ) by the weir equation .
mree = ( 3.94 vo2 + 1.11 vco2 ) 1.44 measurement of the rq was calculated as rq = vco2/vo2 .
man ; pree = 66.47 + 13.75 w + 5.0 h 6.75 a woman ; pree = 665.09 + 9.56 w + 1.84 h 4.67 a where pree stands for resting energy expenditure ( kcal / day ) , w for weight ( kg ) , h for height ( cm ) and a for age ( years ) . differences between groups were analyzed with kruskal - wallis tests . a p value < 0.05 was considered to be statistically significant .
sixteen patients with cd ( 5 women and 11 men , median age 36 years old ) and 8 healthy volunteers were enrolled in this study .
all patients had the diagnosis of cd established by radiological , histological , and clinical criteria . among these patients , two patients had colitic disease , six patients had ileal disease and eight patients had ileocolitic disease .
infliximab therapy has just been started in four patients , and ( oral ) prednisone ( 1030 mg / day ) was taken by five patients .
mrees and respiratory quotients ( rq ) were measured by computed open - circuit indirect calorimetery ( ae-300s ; minato medical science co. , osaka , japan ) .
indirect calorimetry ( ic ) was performed in the hospital room the morning after a 10-h overnight fasting , but infusion of total parenteral nutrition solution were kept on going . period flow and gas calibration were performed prior to measurements . after resting for a minimum of 30 min , patients were assessed in a supine position with a facemask .
after equilibrium was reached for 10 min , respiratory exchange was performed continuously over 30 min .
mree was calculated from oxygen consumption ( vo2 ) and carbon dioxide production ( vco2 ) by the weir equation .
mree = ( 3.94 vo2 + 1.11 vco2 ) 1.44 measurement of the rq was calculated as rq = vco2/vo2 .
man ; pree = 66.47 + 13.75 w + 5.0 h 6.75 a woman ; pree = 665.09 + 9.56 w + 1.84 h
4.67 a where pree stands for resting energy expenditure ( kcal / day ) , w for weight ( kg ) , h for height ( cm ) and a for age ( years ) .
differences between groups were analyzed with kruskal - wallis tests . a p value < 0.05 was considered to be statistically significant .
patients were not significantly different from control subjects in age and height , but had significantly lower body weights , and thus lower bmis ( table 1 ) .
crohn s disease activity index from these patients was 231.3 84.8 , and c - reactive protein was 3.24 4.6 mg / dl .
average hemoglobin , red blood cell count , white blood cell count and platelet count were 10.64 2.1 g / dl , 400.8 62.6 10/mm , 7540 3490/mm , 35.4 12.2 10/mm respectively .
serum albumin and total - cholesterol is 3.46 0.44 g / dl and 127.9 47.6 mg / dl . in cd patients , mree determined by indirect calorimetry was 1271 181.7 kcal / day and pree calculated by the harris - benedict equation was 1372.7 143.7 kcal / day , respectively . as shown in fig . 1
, there were significant correlations between mree and pree in cd patients ( p<0.001 ) as well as in healthy controls ( p<0.05 ) .
both mree and pree in cd patients were slightly lower than those of healthy controls , but there was no significant difference . on the other hand ,
mree / body weight of cd patients ( 24.4 2.4 kcal / kg / day ) was significantly higher than that of healthy control subjects ( 21.3 1.7 kcal / kg / day ) ( table 1 ) .
similarly , pree / body weight of cd patients ( 26.4 2.6 kcal
/ kg / day ) was also significantly higher than that of healthy control subjects ( 22.9 2.6 kcal / kg / day ) ( table 1 ) . in cd patients ,
mree / body weight was significantly lower than pree / body weight ( 26.4 2.5 kcal / kg / day ) ( fig . 2 ) .
in only two patients , mree / body weight was higher than pbee / body weight , and one of them developed complications including an abdominal abscess with fever .
rq in these patients was 0.94 0.14 , and there were significant positive correlations between mree and rq ( fig .
3 ) , whereas there were no significant correlations between mree and rq in healthy controls ( p = 0.075 ) . however , there were no significant correlations between mree and bmi , or between rq and bmi in cd patients .
subjects were also categorized into two groups based on body mass index ( group a ; < 18.5 vs group b ; > 18.5 ) .
there were no significant differences in height , body weight , pree , mree and between groups , but there were significant differences in pree / body weight ( p<0.021 ) .
the mree / body weight in group a ( 24.7 1.2 kcal / kg / day ) was almost same as that of group b ( 24.1 3.0 kcal / kg / day ) .
this study showed that measured ree by ic in hospitalized cd patients was 24.4 2.4 kcal / kg / day , and this was significantly higher than that in healthy controls .
this result suggests that cd patients apparently have a hyper - metabolic status , and supports observations from previous studies [ 1216 ] .
however , mree was significantly lower than pree calculated by the harris - benedict equation in cd patients . usually , energy requirements in hospitalized patients are calculated by pree active factor stress factor .
stress factor in patients with inflammatory bowel disease is recommended as 1.11.3 as well as in patients with cancer and chronic obstructive pulmonary disease .
this adjustment may result in the actual energy expenditure as approximately 45 kcal / kg / day .
however , barot et al . reported that the pbee was equivalent to mree in non - septic cd patients .
they decided that energy requirement were often not greater than the predicted requirement by pree active factor stress factor .
the inflammatory bowel disease study group of the japanese ministry of health , labor and welfare also recommends that total energy of tpn or en should be 4045 kcal / ideal body weight / day in active cd patients .
kcal / kg / day ( 2530 kcal / ideal body weight ) may be ideal as total energy for en or tpn therapies for cd patients by calculating ree 1.21.3 as the active factor .
cd patients certainly have hyper - metabolic statuses , and but high - energy intakes during en or tpn therapies may have a risk of overfeeding .
european guidelines recommend that 2530 kcal / ideal body weight / day is optimal for active crohn s disease .
a previous study showed that rq in active cd is significant lower than in health controls ( cd patients ; 0.78 0.05 versus healthy controls ; 0.86 0.05 ) and energy metabolism in active cd resembled starvation patterns . in this study
, there is a positive correlation between mree / body weight and rq , and this finding shows that fat is mainly oxidated in low metabolic patients .
however , the present results revealed that ( the mean ) rq in hospitalized cd patients was 0.93 0.14 , and there was no significant difference from that found in controls . furthermore , there was no significant difference between rq and bmi , and rq was lower than 0.8 in only a few subjects ( 12.5% ) .
the aforementioned result may be explained by the fact that our patients had already received nutritional therapy .
based on these observations , our results did not support a previous report that energy metabolism of active cd patients mimic starvation patterns .
it has long been hypothesized that increased energy expenditure contributes to weight loss in patients with cd .
however , vaisman et al . reported that mree / pree was higher in a well - nourished cd group than in an undernourished cd group . in this study , mree / body weight in the undernourished group
was found to be equivalent to that in well - nourished group , and mree / pree was slightly higher in the well - nourished group than the undernourished group .
these observations support that increased energy expenditure is not a contributor to the underweight status of cd patients .
however , patients receiving this oral steroid were few in this study ( 31.2% ) .
reported that ree did not change after infliximab therapy , whereas rq increased after infliximab therapy .
their result revealed that lipolysis decreased and starvation improved in cd patients receiving infliximab therapy .
infliximab therapy is now going to be a main therapeutic tool in active cd patients , but nutritional management is necessary in these patients .
ree and rq determinations by indirect calorimetry are useful for cd patients receiving infliximab therapy as well as nutritional therapies . in conclusion
nutritional therapies consisting of 2530 kcal / ideal body weight / day are recommended as optimal for active cd patients . | we investigated energy expenditure in hospitalized patients with crohn s disease ( cd ) , and determined optimal energy requirements for nutritional therapy .
sixteen patients ( 5 women and 11 men , mean age 36 year old , mean bmi 18.7 kg / m2 ) and 8 healthy volunteers were enrolled in this study .
measured resting energy expenditure ( mree ) levels were determined by indirect calorimetry .
the mrees in cd patients were significantly higher than those of healthy controls ( 24.4 2.4 kcal / kg / day vs 21.3 1.7 kcal / kg / day ) .
however , mrees in cd patients were significantly lower than predicted rees ( prees ) calculated by the harris - benedict equation ( 26.4 2.5 kcal / kg / day ) . furthermore , mree / pree values were lower in undernourished patients than in well - nourished patients .
cd patients had hyper - metabolic statuses evaluated by mree / body weight , but increased energy expenditure did not contribute to weight loss in these patients . in conclusion , nutritional therapy with 2530 kcal / ideal body weight / day ( calculated by mree active factor ) may be optimal for active cd patients , while higher energy intake values pose the risk of overfeeding . |
therefore , special attention was paid to the acidic fraction of
the gum resin extracts derived from different boswellia spp
. the acidic fractions ( containing lipophilic acidic ingredients )
of gum resins derived from different boswellia spp .
were separated from the neutral components ( i.e. , the essential oil
and mucilage fraction ) ; see the supporting information .
first , aliquots of the neutral and acidic fractions were analyzed
for inhibition of mpges-1 activity in a cell - free assay using microsomes
of il-1-stimulated a549 cells as enzyme source and 20 m
pgh2 as mpges-1 substrate ; mk-886 ( 10 m ; ic50 = 2.4 m ) was used as reference compound .
response
analysis revealed ic50 values of 1.9 , 2.8 , 1.6 , and 0.4
g / ml for the acidic fraction of gum resins from b.
serrata , b. sacra , b. carterii , and b. papyrifera , respectively ( figure 1b ) .
in contrast , the neutral fraction ( 10 g / ml )
did not significantly inhibit mpges-1 activity , regardless from which
species it originated ( not shown ) .
in particular , the acidic fraction
of b. papyrifera gum potently suppressed mpges-1
activity with a maximal inhibition of 92% at 30 g / ml , which
was superior to the control inhibitor mk-886 ( 10 m = 0.49 g / ml ,
79% inhibition ) under the same assay conditions .
therefore , the remarkable
potency of the acidic fraction of b. papyrifera gums suggested the presence of highly
active constituents .
it should be noted that the nature of the ingredients
and their contents do not substantially differ between lipophilic
extracts of gum resins from these four boswellia spp . , indicating that defined mixtures or compositions
of the bioactive components may result in efficient mpges-1 inhibition .
microsomal
preparations of il-1-stimulated a549 cells were
preincubated with the indicated concentrations of acidic fractions
derived from gums of b. papyrifera , b. serrata , b. sacra , and b. carterii , or
vehicle ( dmso ) , for 15 min at 4 c .
the reaction was started
by addition of 20 m pgh2 , and after 60 s at 4 c ,
the reaction was terminated and pge2 was analyzed .
besides the four boswellic acids 14 that were recently shown to inhibit mpges-1 , the acidic fractions of frankincense gum resins
may contain
additional triterpene acids that could interfere with mpges-1 activity
as well .
we isolated 17 known triterpene acids ( table 1 ) from various gum resins of different boswellia spp .
( see supporting information ) , that
is , the four boswellic acids 14 ,
the six tirucallic acids 510 , the
three roburic acids 1113 , the nyctanthic
acid 14 , and the three lupeolic acids 1517 , by preparative hplc .
the chemical structures
of the isolated compounds were analyzed by ms and nmr and compared
to literature data ( see supporting information ) .
the 13 remaining triterpene acids 517 were tested at a fixed concentration
of 10 m ( table 1 ) .
the roburic acids 11 and 12 as well as the nyctanthic acid 14 failed to significantly inhibit mpges-1 activity , whereas
all tirucallic acids ( 510 ) , the
roburic acid 13 , and the three lupeolic acids 1517 markedly suppressed pge2 production
( table 1 ) . just like mk-886 ( at 10 m ) ,
all these active compounds exerted a maximal inhibition of about 70%
to 80% , except 5 , which was able to suppress pge2 formation by 96% ( table 1 ) . those
triterpene acids that caused more than 60% inhibition at 10 m
were subjected to concentration response analysis . as depicted
from table 1 , the six tirucallic
acids 510 , the roburic acid 13 , and the lupeolic acid 17 potently suppressed
mpges-1 activity with ic50 values of 0.4 to 3 m .
in comparison to the boswellic acids 14 as inhibitors of mpges-1 ( ic50 = 330 m )
the two acetylated tirucallic acids 6 and 10 with ic50 = 0.4 m ,
each , were most potent , whereas the corresponding deacetylated analogues 5 and 9 were less efficient ( ic50 =
1.1 and 3.0 m , respectively ) ( figure 2 ) . concentration
microsomal preparations of il-1-stimulated
a549 cells were preincubated with ( a ) 3--hydroxy-8,24-dienetirucallic
acid ( 5 ) , ( b ) 3-acetoxy-8,24-dienetirucallic acid
( 6 ) , ( c ) 3--hydroxy-7,24-dienetirucallic acid
( 9 ) , and ( d ) 3-acetoxy-7,24-dienetirucallic acid
( 10 ) at the indicated concentrations for 15 min at 4
c .
the reaction was started by addition of 20 m pgh2 , and after 60 s at 4 c the reaction was terminated
and pge2 was analyzed data are given as mean + sem , n = 47 . from this structure activity - relationship ( sar )
study ,
we
conclude that the acetylation of the free hydroxyl moiety at the 3
position of 6 and 10 is seemingly beneficial .
on the other hand , replacement of the 3-hydroxy group of 5 ( ic50 = 1.1 m ) by a keto group yielding 8 exhibited no significantly improved potency ( ic50 = 0.9 m ) .
moreover , 3-configured 7 showed
almost the same inhibitory potency ( ic50 = 1.2 m )
as its 3-isomer 5 , indicating that the steric
positioning of the 3-hydroxy group has negligible impact on the bioactivity .
among the roburic acids , the derivative 13 , carrying
a keto moiety , potently inhibited mpges-1 activity ( ic50 = 1.0 m ) , whereas 11 and 12 ( without
the keto group ) were not active up to 10 m .
along these lines ,
the nyctanthic acid 14 , also lacking a keto moiety , which
is structurally related to the roburic acid 12 , was also
inactive .
inhibition of mpges-1 by lupeolic acids was evident for
all tested derivatives 1517 , but
only the acetylated derivative 17 reached an ic50 ( i.e. , 0.9 m ) lower than 10 m , suggesting that the
additional hydroxyl moiety at position c(28 ) is responsible for this
molecule s bioactivity .
in contrast to boswellic acids ,
few studies have addressed the
bioactivities and pharmacological properties of tirucallic acids and
lupeolic acids .
thus , tirucallic acids were found to modulate 5-lipoxygenase
product synthesis and to inhibit the
serine / threonine kinase akt in prostate cancer cells in association
with apoptotic cell death .
cancer chemopreventive
and cytotoxic activities in neuroblastoma cell lines were reported
for the lupeolic acids 15 and 16 , albeit
at high concentrations ( ic50 = 4.186.7 m ) , and both compounds ( applied topically ) inhibited
phorbol ester - induced ear inflammation in mice . for roburic acids ,
only one study on bioactivity has been
published that describes moderate inhibitory effects on isolated cox
enzymes ( ic50 > 10 m ) .
therefore , the identification of mpges-1 as a target for the tirucallic
acids 510 , the roburic acid 13 , and the luepolic acid 17 is a substantial
insight into the pharmacology of these triterpene acids and underlines
their anti - inflammatory and anticancer potential , which was proposed
for other mpges-1 inhibitors .
the
fact that several different structural classes of triterpene acids
inhibit mpges-1 , while other derivatives failed , led us to deduce
sars in order to speculate about a common binding pattern of active
compounds . in silico docking studies were performed
to surmise binding modes of triterpene acids in mpges-1 .
the tirucallic
acids 5 and 10 , the lupeolic acid 17 , and the boswellic acid 1 were analyzed for
common chemical features relevant to potent mpges-1 inhibition and
to compare the binding mode of these triterpene acids with less active
derivatives .
the tirucallic acid 10 , one of the most
potent derivatives ( ic50 = 0.4 m ) , exhibited various
molecular interactions , which were subjected to subtle modifications
during the mmff94-based minimization within ligandscout ( figure 3a ) .
for instance , the arg73 of subunit a , which
we refer to as arg73a , extended as a solvent - exposed residue into
the central pore of the homotrimeric mpges-1 . during the minimization ,
arg73a shifted toward the acidic moiety of 10 , making
an ionic interaction feasible . additionally , the acidic group of 10 formed an ionic interaction with arg70a , a residue near
the cofactor glutathione ( gsh ) .
we additionally
observed various hydrophobic interactions between 10 and
residues embedded in the central pore ( e.g. , leu69a , val65b , leu69b ,
and val65c ) .
for comparison , the tirucallic acid 5 ( ic50 = 1.1 m ) ( figure 3b ) and the
lupeolic acid 17 ( ic50 = 0.9 m ) ( figure 3c ) formed an ionic interaction or a hydrogen bond
to arg73c or arg73a , respectively . additionally , in the case of 5 , a hydrogen bond was formed between the hydroxyl group of
the triterpene acid and gsh , while , in the case of 17 , a hydrogen bond was formed between the acetoxy group and the backbone
amide of his53a . predicted binding modes for representative triterpene
acids using
molecular docking . predicted binding modes
are shown for ( a ) 3-acetoxy-7,24-dienetirucallic
acid ( 10 ) ( b ) , 3--hydroxy-8,24-dienetirucallic
acid ( 5 ) , ( c ) 3-o - acetyl-28-hydroxylupeolic
acid ( 17 ) , and ( d ) -boswellic acid ( 1 ) . protein
ligand interactions are color - coded : red arrow ,
hydrogen - bond acceptor ; green arrow , hydrogen - bond donor ; yellow sphere ,
hydrophobic interaction ; red star , negatively ionizable .
interestingly , the sec - propenyl
group of 17 protruded into the region adjacent to the
cofactor gsh
and formed a hydrophobic interaction with leu69b .
finally , the boswellic
acid 1 , with less pronounced potency toward mpges-1 ( ic50 = 5 m ) , was docked into
the 3d structure of mpges-1 ( figure 3d ) .
this
boswellic acid was predicted to form a hydrogen bond to arg73b , similar
to the other triterpene acids . although hydrophobic interactions were
formed ( e.g. , with val65b and leu69b ) , similar to other triterpene
acids ,
these molecular interactions were less frequently observed
for 1 compared to the other more potent compounds .
together , a hydrogen bond or an ionic interaction of the carboxylic
group to arg73 , which extends into the central pore of the homotrimeric
enzyme , is observed in all docking poses .
thus , the acidic group of 510 , 13 , and 17 may essentially contribute to the potent interference of these triterpene
acids with mpges-1 .
however , additional interactions involving oxygen - containing
substituents determine the potency , since 11 , 12 , and 14 , lacking an additional oxygen substituent ,
failed to inhibit mpges-1 , and also 15 and 16 , lacking the c(28)oh , were less active than 17 .
in contrast , all six tirucallic acids ( 510 ) that carry an oxygen ( hydroxyl , keto , or acetoxy group )
distant from the carboxylic acid moiety potently suppressed mpges-1
activity with ic50 values of 0.4 to 3 m . also , 13 and 17 substituted with a hydroxyl or keto
group potently suppressed mpges-1 activity .
therefore , the presence
of oxygen distant from the carboxylic moiety is seemingly important
for molecular interactions with mpges-1 .
moreover , the docking studies
imply that hydrophobic interactions , which were frequently formed
to residues embedded in the central pore ( e.g. , val65 , leu69 , and
met76 ) , seem to contribute to mpges-1 interference .
furthermore , among
the most potent triterpene acids ( e.g. , 5 and 10 ) , an ionic interaction to a residue near gsh ( e.g. , arg70 ) or a
hydrogen bond formed directly with gsh could be observed in the molecular
docking . for generation of the proinflammatory pge2 ,
the release
of aa as substrate and its conversion by cox enzymes are essential
upstream processes leading to the formation of pgh2 as
substrate for various prostanoid synthases . as mpges-1 is considered to be a valuable drug target for selective
inhibition of pge2 biosynthesis
, a concomitant suppression
of cox enzymes would obliterate the selectivity of such compounds .
in fact , the boswellic acids 14 , the tirucallic acid 6 , and the roburic acid 11(22 ) were reported to inhibit cox enzymes , though at higher concentrations ,
in the two - digit micromolar range . to estimate the selectivity of
the triterpene acids that potently inhibited mpges-1 activity with
ic50 < 3 m ( i.e. , 510 , 13 , and 17 ) , the impact on cox
enzymes was analyzed . in cell - free assays using purified ovine cox-1
or purified human recombinant cox-2 ,
the triterpene acids ( 10 m )
elicited only moderate inhibitory effects without statistical significance
( p > 0.05 ; table 2 ) .
,
we analyzed the major triterpene acids present in
gum resins of boswellia spp .
for
their ability to interfere with mpges-1 , and we identified six tirucallic
acids ( 510 ) , one lupeolic acid ( 17 ) , and one roburic acid ( 13 ) as potent inhibitors
of this enzyme .
of interest , these triterpene acids , except 9 , inhibit mpges-1 activity with improved potency ( ic50 = 0.41.2 m ) as compared to boswellic acids
( ic50 = 330 m ) .
molecular docking simulations confirm the improved potencies of
tirucallic acids and lupeolic acids , as hydrogen bonds to or ionic
interactions with the cofactor gsh , the neighboring arg70 , or arg73
mediate tight binding , whereas the boswellic acid 1 forms
hydrophobic interactions at a greater distance to the cofactor gsh ,
implying weaker binding .
we suggest that mpges-1 is a major target
of several triterpene acids that are contained in gum resins of certain boswellia spp . , and suppression of mpges-1 by these compounds
may underlie their beneficial properties in the treatment of painful
inflammatory disorders .
the structures of the
triterpene acids used in this study have been described previously
and were isolated from the gum resin of b. serrata , b. papyrifera , b. carterii , and b. socotrana , respectively .
the gum resins from b. serrata , b. papyrifera , b. carterii , and b. sacra were purchased from gerhard eggebrecht
vegetabilien & harze , sderau , germany , whereas the gum
resin of b. socotrana was a gift by the botanical
garden and botanical museum ( bgbm ) in berlin - dahlem , germany .
fractions obtained by extraction and/or chromatography
were stored in a refrigerator at 30 c until they were
used .
structure elucidation was done by 1d- and 2d - nmr spectroscopy
on a bruker av ii 400 and/or a bruker av 500 nmr spectrometer . as
1d - nmr spectra , h , c , dept90 , and dept135
spectra
h - gs - dqf - cosy , hmqc , hmqc - cosy ,
hmbc , and noesy spectra were recorded .
the molecular formula was calculated
from hrms spectra obtained with mat95s ( hrms with ci ) from bruker .
esi mass spectra were measured with zq4000 from waters ( esi in the
negative ion mode ) . for more details , see the supporting information .
then , it was finely
ground in a laboratory mill and extracted in a soxhlet extractor with
distilled dichloromethane for 16 h. a 180 g amount of the finely ground
resin was extracted with ca .
the solvent was evaporated
with the aid of a rotary evaporator at 40 c under vacuum ( ca .
the residue ( raw extract ) was dissolved in 200 ml of diethyl
ether and extracted with 200 ml of 5% ( m / v ) aqueous koh in a separatory
funnel . after separating the phases ,
the alkaline aqueous phase was
extracted three times with 50 ml of diethyl ether each .
the combined
ethereal phases were washed with brine ( 20 ml ) and dried with mgso4 .
after filtration of the drying agent , the diethyl ether
was evaporated under vacuum in a rotary evaporator .
the alkaline
aqueous phase from above was cooled in an ice bath and carefully acidified
with ice cold , concentrated aqueous hydrochloric acid .
the combined extracts were washed with brine ( 20 ml ) and dried
over mgso4 .
after filtration of the drying agent , the solvent
was evaporated under vacuum . the remaining yellow to orange foam is
the acidic fraction of the resin and contains all lipophilic acids
of the particular resin .
the amounts of the neutral fraction and the
acidic fraction depend strongly on the particular resin .
the column
was packed with a slurry of silica gel ( normal phase
np , merck ag , darmstadt , germany ) with particle size from 40 to 63
m in the appropriate mobile phase .
after covering the silica
gel with a small pad of purified sand , the sample , dissolved in a
small amount of mobile phase , was applied on top of the column .
elution
of the compounds was done with 500 ml portions of mobile phase ( usually
pentane / diethyl ether + 1% ( v / v ) of acetic acid ) with stepwise increasing
polarity ( starting with pentane / diethyl ether , 8:1 , then 7:1 , then
6:1 , and so on up to pentane / diethyl ether , 1:2 ) .
ml each ) were collected in test tubes with the aid of a fraction
collector .
analysis of the fractions was done with tlc ( merck glass
plates ) with a suitable solvent .
fractions with similar composition
were combined , and the solvent was evaporated to dryness . usually ,
a bright yellow to orange foam is obtained .
these combined fractions
were analyzed by analytical hplc and further separated by preparative
hplc .
preparative hplc was done with a preparative hplc pump
model sykam s1521 ( sykam , frstenfeldbruck , germany ) , a rheodyne
injection valve type 7725i , a diode array detector model sykam s3210
( sykam , frstenfeldbruck , germany ) , and chromstar 6.0 software
( scpa , weyhe - leeste , germany ) . as a column , a semipreparative nucleodur
100 - 5 c18 ec , 5
m , 250 20 , from machery &
nagel , dren , germany , was used .
the purity of the isolated
compounds used for biological evaluation was at least 95% .
g / l )
medium , penicillin , streptomycin , trypsin / edta solution , paa ( coelbe ,
germany ) , pgh2 ( larodan , malm , sweden ) , 11-pge2 and mk-886 ( biotrend chemicals gmbh , cologne , germany ) , arachidonic
acid , and fetal calf serum were used , and all other chemicals were
obtained from sigma - aldrich ( deisenhofen , germany ) unless stated otherwise .
induction
of mpges-1 expression in a549 cells and isolation of microsomes
were performed as described . in brief
,
cells were incubated for 16 h at 37 c and 5% co2 ,
and after changing the medium , mpges-1 expression was induced by il-1
( 1 ng / ml ) . after 72 h , cells were frozen in liquid nitrogen , ice - cold
homogenization buffer ( 0.1 m potassium phosphate buffer ph 7.4 , 1
mm phenylmethanesulfonyl fluoride , 60 g / ml soybean trypsin
inhibitor , 1 g / ml leupeptin , 2.5 mm gsh , and 250 mm sucrose )
was added , and after 15 min cells were resuspended and sonicated on
ice ( 3 20 s ) .
the homogenate was then subjected to differential
centrifugation at 10000 g for 10 min and at 174000 g for 1 h at 4 c .
the pellet ( microsomal fraction )
was finally resuspended in 1 ml of homogenization buffer , and the
protein concentration was determined by the coomassie protein assay .
microsomal membranes of a549 cells were diluted in potassium phosphate
buffer ( 0.1 m , ph 7.4 ) containing 2.5 mm gsh ( 100 l total volume ) ,
and pge2 formation was initiated by addition of pgh2 ( 20 m , final concentration ) .
after 1 min at 4 c ,
the reaction was terminated with 100 l of stop solution ( 40
mm fecl2 , 80 mm citric acid , and 10 m 11-pge2 ) , and pge2 was separated by solid - phase extraction
and analyzed by rp - hplc as described .
briefly , purified cox-1 ( ovine , 50 units ) or
cox-2 ( human recombinant , 20 units ) was diluted in 1 ml of reaction
mixture containing 100 mm tris buffer ph 8 , 5 mm glutathione , 5 m
hemoglobin , and 100 m edta at 4 c and preincubated with
the test compounds for 5 min .
samples were prewarmed for 60 s at 37
c , and aa ( 5 m for cox-1 , 2 m for cox-2 ) was added
to start the reaction .
after 5 min at 37 c , 12(s)-hydroxy-5z,8e,10e - heptadecatrienoic acid was extracted and then analyzed by hplc .
the binding modes of the investigated
triterpene acids were analyzed using the quantum mechanics - polarized
ligand docking ( qpld ) workflow , which is available
in the maestro suite version 9.2.112 .
for this purpose , the x - ray crystal structure of mpges-1 with bound
cofactor gsh was used , which is deposited in the protein data bank
( pdb , http://rcsb.org/pdb/ ) , entry 3dww . for the docking procedure ,
2d
structures of the triterpene acids were converted into 3d coordinates
employing maestro s module ligprep .
this included the ionization
of acidic moieties of the ligands with the module ligprep ( epik / opls-2005 ) .
the
hydrogen atoms were added , and atom and bond types were assigned ,
which was followed by exploration of the hydrogen bond assignment
in extensive mode . within this procedure ,
furthermore , the protein was refined by
a minimization as a final step of the protein preparation within the
respective assistant ( opls - aa 2005/rmsd threshold : 0.3 ) .
the
molecular docking was performed with glide in extra precision ( xp )
mode and a scaling of the receptor van der waals radius by a factor
of 0.9 . in the qpld workflow
, the proposed orientation of the ligands
within the binding site of the macromolecule target is used to calculate
atomic ( partial ) charges of the ligands employing the quantum mechanical / molecular
mechanical ( qm / mm ) approach performed with the module qsite ( semiempirical
method / mulliken charges ) .
the initial docking poses were submitted
to a second docking procedure with glide in xp mode , involving atomic
( partial ) charges of ligands from the qm / mm approach .
the final docking
poses were ranked according to the calculations from the glidescore
scoring function .
the analysis of the docking poses , which were retrieved
from the qpld workflow , was performed within ligandscout version 3.1 following an mmff94-based minimization of the investigated triterpene
acid and of the binding site residue side chains within ligandscout ,
which was also used for visualization purposes .
, san diego , ca , usa )
was used for statistical comparisons of the data by one - way anovas
for independent or correlated samples followed by tukey hsd post hoc tests . where appropriate , student s t test for paired and correlated samples was applied
ic50 values of compounds are approximations determined by graphical
analysis ( linear interpolation between the points between 50% activity ) . | the microsomal prostaglandin e2 synthase ( mpges)-1 is
the terminal enzyme in the biosynthesis of prostaglandin ( pg)e2 from cyclooxygenase ( cox)-derived pgh2 .
we previously
found that mpges-1 is inhibited by boswellic acids ( ic50 = 330 m ) , which are bioactive triterpene acids present
in the anti - inflammatory remedy frankincense .
here we show that besides
boswellic acids , additional known triterpene acids ( i.e. , tircuallic ,
lupeolic , and roburic acids ) isolated from frankincense suppress mpges-1
with increased potencies . in particular , 3-acetoxy-8,24-dienetirucallic
acid ( 6 ) and 3-acetoxy-7,24-dienetirucallic acid
( 10 ) inhibited mpges-1 activity in a cell - free assay
with ic50 = 0.4 m , each . structure
activity
relationship studies and docking simulations revealed concrete structure - related
interactions with mpges-1 and its cosubstrate glutathione .
cox-1 and
-2 were hardly affected by the triterpene acids ( ic50 >
10 m ) .
given the crucial role of mpges-1 in inflammation and
the abundance of highly active triterpene acids in frankincence extracts ,
our findings provide further evidence of the anti - inflammatory potential
of frankincense preparations and reveal novel , potent bioactivities
of tirucallic acids , roburic acids , and lupeolic acids . |
the online version of this article ( doi:10.1007/s00018 - 014 - 1758 - 1 ) contains supplementary material , which is available to authorized users .
the human skin is our outermost layer that protects us against physical , chemical , and biological assaults from the external environment .
after birth , our skin constantly renews ; and the dead , cornified keratinocytes are shed off from our body and replaced by new ones originating from stem cells located in the basal layer .
human epidermal homeostasis results from exquisite control of the keratinocyte switch from the proliferative stage in the basal layer to the commitment to terminal differentiation in the suprabasal layer of the epidermis .
several studies have unraveled some of the molecular actors that participate in the regulation of epidermal homeostasis . among them , myc , notch , wnt , mapks , e2f , rb , and p63 [ 710 ] seem particularly important .
p63 is a member of the p53 protein family and is a master regulator in the control of the basal
p63 is highly expressed in the basal layer of the epidermis and participates in the maintenance of the stemness of keratinocytes in the interfollicular epidermis [ 12 , 13 ] . upon loss of p63
, basal cells failed to divide asymmetrically , leading to the loss of stratification and differentiation [ 7 , 13 ] . in an elegant study using reconstructed human epidermis
, the group of khavari showed that p63 is required for the proliferation and differentiation of developmentally mature keratinocytes via two independent mechanisms . although p63-deficient cells exhibited hypoproliferation , their inability to differentiate was not due to tissue hypoplasia .
simultaneous p63 and p53 knockdown rescued the cell proliferation defect but failed to restore differentiation in p63-knockdown cells , suggesting that defects in epidermal proliferation and differentiation are mediated via p53-dependent and -independent mechanisms , respectively .
however , the underlying molecular mechanisms seem complex , and truong et al . concluded that determining the direct downstream effectors of p63 that mediate epidermal differentiation program is of great interest for future studies .
identification of key genes downstream of p63 would provide important new insights into its roles in dynamic equilibrium of differentiation and proliferation .
several approaches have been taken over the last few years to identify the molecular actors acting downstream of p63 , notably genome - wide p63 chip analyzes to characterize p63 dna targets at the genomic scale . in 2006
we undertook a chip - on - chip screening approach using the human keratinocyte cell line hacat , which predominantly expresses the np63a isoform , a truncated n amino terminal isoform that lacks the transactivating domain of p63 and were the first to identify 186 high - confidence p63 targets , which were validated using different biological assays .
we then reanalyzed these data with less stringent criteria , extended the list of targets to over 1,000 , and confirmed the pivotal role of p63 in transcriptional regulation .
however , the genome coverage was limited in our studies . indeed , the 12k promoter array which we used contained 12,000 promoter regions extending from approximately 800 bp upstream to approximately 200 bp downstream of the transcription start site , while the 12k cpg islands array contained probes with a median of approximately 300 bp , most being proximal to the transcription start site . using a tiled , whole genome array from affymetrix to cover a larger area of the genome , yang et al
[ 18 , 19 ] first performed a chip - seq analysis of the p63 binding sites in the human genome of primary keratinocytes and found 10,895 genes that had one or more p63 binding sites within 25 kb up and downstream of the gene .
a similar study recently identified 6,172 potential p63 target genes within 25 kb of p63 binding sites .
together , these results suggest that gene networks acting downstream of p63 are extremely complex .
this was confirmed by several transcriptome studies that compared the gene expression in human p63-depleted versus wild - type keratinocytes [ 10 , 20 ] .
recently , we generated an expression profile in human keratinocytes lacking p63 and compared it with that of normal cells . despite the use of multiple biological replicates and a stringent statistical threshold ( fold change 1.2 and p value 0.001 ) , we characterized more than 1,000 genes that were modulated in p63-knockdown cells . facing this complexity , we hypothesized that the regulation of epidermal homeostasis in adult humans could rely on gene networks and the dynamics of expression rather than on individual genes and absolute values of expression .
when analyzing the expression profiles of p63-depleted keratinocytes , we soon observed that myc was down - regulated in these cells .
no evidence has ever demonstrated any connection between these two genes in the regulation of epidermal homeostasis ; therefore , we decided to compare the transcriptomes and phenotypic outcomes in human keratinocytes lacking either gene . because of the existence of six different isoforms of p63 , we used a sirna targeting the conserved dna - binding domain in all genes to achieve ablation of all p63 isoforms ( sip63 ) , and we use a sirna targeting myc ( simyc ) .
the knockdown of either myc or p63 in developmentally mature human keratinocytes resulted in impaired proliferation . because myc does not seem to be a direct target of p63 [ 15 , 16 ] , the downregulation of myc in p63-depleted keratinocytes was likely indirect .
indeed , through analysis of the myc promoter region , we determined that p63 regulates myc expression via the wnt and notch signaling pathways , which , in turn , are responsible for p63-dependent regulation of myc .
furthermore , we have characterized a cell cycle network centered on myc that is composed of cell cycle - related genes mainly located in the nucleus and that control cell proliferation .
the network is down - regulated in both genetic backgrounds , either myc- ( fig .
it is very likely that p63 can either directly or indirectly regulate other cell cycle genes independent of myc .
truong et al . demonstrated that cell cycle arrest in p63-deficient keratinocytes was p53-dependent .
our result observed both in the hacat cell line ( mutated p53 ) and in normal human primary keratinocytes ( wild - type p53 ) demonstrated that cell cycle arrest in p63-depleted keratinocyte could also be p53-independent and myc - dependent .fig .
genetic networks regulating the cell cycle consist of common genes that are modulated in myc- or p63-knockdown keratinocytes .
the lists of genes were obtained from transcriptome profiling of hacat cells treated with a sirna targeting myc ( simyc ) a or a sirna targeting all isoforms of p63 ( sip63 ) b after 48 h. the complete list of gene can be found in wu el al .
networks were extracted using the ingenuity pathway assist software ( http://www.ingenuity.com/products/ipa ) . nodes ( genes or proteins ) in the networks are indicated by different shapes ( biological functions ) and colors ( red indicates up - regulated , and green represents down - regulated ) .
edges are represented as solid or dashed lines to indicate direct and indirect interactions , respectively cell cycle network that controls keratinocyte proliferation .
genetic networks regulating the cell cycle consist of common genes that are modulated in myc- or p63-knockdown keratinocytes .
the lists of genes were obtained from transcriptome profiling of hacat cells treated with a sirna targeting myc ( simyc ) a or a sirna targeting all isoforms of p63 ( sip63 ) b after 48 h. the complete list of gene can be found in wu el al .
nodes ( genes or proteins ) in the networks are indicated by different shapes ( biological functions ) and colors ( red indicates up - regulated , and green represents down - regulated ) .
edges are represented as solid or dashed lines to indicate direct and indirect interactions , respectively
we observed that the ablation of p63 inhibited keratinocyte differentiation , while cells lacking myc were still able to differentiate .
again , we compared the expression profiles in myc - depleted keratinocytes with those of cells lacking p63 and identified a gene network common to p63- and myc - knockdown keratinocytes that was oppositely regulated . this network is composed mainly of cell adhesion- and migration - related genes that are located in the cytoplasm , plasma membrane , and even secreted outside of cells ( fig . 2 ) .
further studies demonstrated that this network plays a significant role in keratinocyte cell fate ; therefore , we named it the keratinocyte cell fate ( kcf ) network .
to summarize , the kcf network was up - regulated in keratinocytes lacking myc ( fig .
we cultured hacat cells in a low calcium concentration medium until confluence to induce the onset of keratinocyte differentiation .
therefore , cells began to differentiate only when they received confluence signals upon contact with other cells , and , as a consequence , it makes sense that this network is up - regulated upon keratinocyte differentiation .
strikingly , all studies on the analysis of p63 target sites in the human genome have shown enrichment in genes involved in cell adhesion : 336 genes ( p value = 3.73e12 ) and 286 genes ( p value = 1.52e11 ) . furthermore , carroll et al
. demonstrated that knockdown of p63 in mammary epithelial cells caused the downregulation of cell adhesion - associated genes .
lastly , numerous studies have established a clear link between cell adhesion and differentiation [ 2628].fig .
genetic networks involved in keratinocyte differentiation consist of common genes that are oppositely modulated in myc- or p63-knockdown keratinocytes .
the lists of genes were obtained from transcriptome profiling of hacat cells treated with a sirna targeting myc ( simyc ) a or a sirna targeting all isoforms of p63 ( sip63 ) b after 48 h. the complete list of genes can be found in wu et al . .
networks were extracted using the ingenuity pathway assist software ( http://www.ingenuity.com/products/ipa ) . nodes ( genes or proteins ) in the networks are indicated by different shapes ( biological functions ) and colors ( red indicates up - regulated , and green represents down - regulated ) .
edges are represented as solid or dashed lines to indicate direct and indirect interactions , respectively keratinocyte cell fate network .
genetic networks involved in keratinocyte differentiation consist of common genes that are oppositely modulated in myc- or p63-knockdown keratinocytes .
the lists of genes were obtained from transcriptome profiling of hacat cells treated with a sirna targeting myc ( simyc ) a or a sirna targeting all isoforms of p63 ( sip63 ) b after 48 h. the complete list of genes can be found in wu et al . .
networks were extracted using the ingenuity pathway assist software ( http://www.ingenuity.com/products/ipa ) . nodes ( genes or proteins ) in the networks are indicated by different shapes ( biological functions ) and colors ( red indicates up - regulated , and green represents down - regulated ) .
edges are represented as solid or dashed lines to indicate direct and indirect interactions , respectively our data suggest that upregulation of the kcf network is associated with terminal differentiation . however , whether it is the consequence or the cause of differentiation remains to be elucidated . to address this issue , the functional importance of genes such as fn1 , jag1 , cyr61 , and
interestingly , sirna - mediated knockdown of these four genes systematically delayed the onset of terminal differentiation .
based on our results and other studies , we propose a wind rose model that dictates human kcf ( fig . 3 ) . in this model ,
cell fate is determined by two gene networks : the cell cycle network , which controls cell proliferation and the kcf network .
the proper balance in expression of these two networks would control the balance between cell proliferation and differentiation and eventually kcf .
different combinations of the expression levels of these two networks in response to various genetic perturbations would direct four possible phenotypic outcomes for keratinocytes : cancer , induced pluripotent stem cells , inhibited differentiation , and accelerated differentiation ( fig .
the coordinated regulation of two different gene networks : the cell cycle network and the keratinocyte cell fate ( kcf ) network , dictates the fate of human keratinocytes and regulates epidermal homeostasis the wind rose model of human keratinocyte cells fate .
the coordinated regulation of two different gene networks : the cell cycle network and the keratinocyte cell fate ( kcf ) network , dictates the fate of human keratinocytes and regulates epidermal homeostasis in our experimental model , knockdown of p63 resulted in proliferation defects due to downregulation of the myc - controlled cell cycle progression network ( fig . 1 ) .
this leads to proliferation defects in p63-silenced keratinocytes , further demonstrating the essential role of p63 in regulating keratinocyte proliferation .
furthermore , the lack of p63 downregulates the kcf network ( fig . 2 ) , which is composed of genes associated with cell adhesion / migration .
the decrease expression of both cell cycle and kfc networks in p63-silenced keratinocytes resulted in inhibited differentiation ( fig . 3 , lower - left corner of the wind rose , in blue ) .
if one moves clockwise through the wind rose , we next analyze the consequences of myc silencing in human keratinocytes ( fig . 3 , upper - left corner of the wind rose , in orange ) .
in myc - depleted keratinocytes , we observed downregulation of the cell cycle network as in p63-depleted cells , whereas the kcf network was up - regulated , resulting in accelerated differentiation , unlike keratinocyte lacking p63 .
these results suggest that cell cycle withdrawal is necessary but not sufficient to promote differentiation . still moving clockwise , studies from a ras - induced skin tumor model from khavari s group ( fig .
3 , upper - right corner of the wind rose , in red ) demonstrated that a network sharing many genes with both the kcf and cell cycle networks was up - regulated upon ectopic expression of ras .
indeed , this group reported a core tumor progression signature ( ctps ) network in human keratinocytes that contained 292 nodes and was involved in carcinogenesis .
this ctps network contained several oncogene hubs , and 8 of the top 10 nodes were extracellular or cell - surface proteins related to adhesion .
it is noteworthy that 4 of these 8 extracellular oncogene hubs , i.e. , plau , cyr61 , fn1 , and il1 , also belong to the p63-regulated kfc network that we have characterized .
finishing the wind rose tour , transcriptome data from stem cells show that 7 hubs that we identified in the kcf network , plau , fn1 , il1b , adm , dusp10 , gadd45 and rac2 were significantly down - regulated in embryonic stem cells and in induced pluripotent stem ( ips ) cells when compared with fibroblasts ( fig . 3 , lower - right corner of the wind rose , in green ) .
strikingly , the transcriptomics signature of human ips shows downregulation of 6 of the 8 oncogene hubs that were reported in both the ctps and kfc networks . on the contrary ,
the myc - centered cell cycle network is up - regulated in ips cells as indeed ectopic expression of myc , along with 3 other genes , is necessary for ips generation . in conclusion
reconciles much of the existing data on the regulation of the balance between proliferation and differentiation in human skin cells and the regulation of epithelial homeostasis .
lastly , this model may enable the generation of new hypothesis and therapeutic strategies for skin diseases , including cancer .
supplementary material 1 ( docx 1221 kb ) supplementary material 2 ( pdf 3514 kb ) | extensive efforts have been made to understand the molecular actors that control epithelial cell fate . although pieces of information have been obtained from single - gene function investigations , the entire picture of the molecular mechanisms involved in the regulation of epithelial homeostasis is still mysterious .
growing data indicate that gene networks rather than single master
genes dictate cell fate . in an attempt to characterize such gene networks ,
we have been investigating the human keratinocyte proliferation and differentiation genes that act downstream of the transcription factor p63 , a major regulator of epidermal homeostasis .
we identified two networks : the cell cycle network that controls cell proliferation and the keratinocyte cell fate network . through further analysis of the existing data on epithelial tumorigenesis and
induced pluripotent stem cells , we propose a wind rose model of cell fate that is based on a balance between these two different networks that ultimately control human keratinocyte fate and epidermal homeostasis.electronic supplementary materialthe online version of this article ( doi:10.1007/s00018 - 014 - 1758 - 1 ) contains supplementary material , which is available to authorized users . |
especially the genesis of tumors of the gastrointestinal tract seems to depend on genetic predisposition , environmental factors , and diet .
evidence has been provided that these factors directly influence epigenetic mechanisms associated with cancer development in humans .
dna methylation / demethylation and histone modifications are controlled by specific enzymes , such as dna methyltransferase ( dnmt ) , histone acetyltransferase ( hat ) , and histone deacetylase ( hdac ) [ 3 , 4 ] .
one of the major posttranslational epigenetic regulations of gene expression is the modulation of histones via acetylation and deacetylation .
hdacs belong to the group of zinc - binding metalloenzymes catalyzing the elimination of acetyl groups from histone tails .
deacetylation results in the tighter wrapping of dna around the histone core leading to chromatin condensation . based on this cellular event the accessibility of transcription factors and gene expression is decreased .
hdacs are involved in several cellular regulation processes such as transcription , cell cycle progressing , gene silencing , cell differentiation , dna - replication and dna - damage response [ 5 , 6 ] . up to now
, 18 human hdac enzymes are characterized and classified into four classes : class i hdacs share sequence similarity with the yeast rpd3 deacetylase ; they are ubiquitously expressed and are localized in the nucleus .
hdacs of class ii are homologous to the yeast hda1 deacetylase and translocate between cytoplasm and nucleus .
class iii hdacs are represented by sirtuins , a family of seven hdacs sharing homology with the yeast silent information regulator 2 protein ( sir2 ) .
class iv hdac11 shares conserved residues with both class i and ii hdacs [ 79 ] .
various tumor types mainly overexpressed class i hdacs associated with drug resistance and poor prognosis .
hdac inhibitors have emerged as a promising class of therapeutic drugs used in the therapy of alzheimer or parkinson disease and cancer [ 1117 ] .
epidemiological studies indicate that cancer incidence might be significantly modulated by an enhanced dietary intake of polyphenols with fruits and vegetables [ 18 , 19 ] . based on the proposed health benefits ,
polyphenol preparations have gained increasing popularity on the fast expanding market of food supplements . within the class of polyphenols the major green tea catechin ( )-epigallocatechin-3-gallate ( egcg ) , the stilbene resveratrol ( found in grapes and wine ) , several soy isoflavones and carboxylic acid derivatives such as chlorogenic acid ( cga ) or caffeic acid
have been extensively reported to affect hdac activity , and all are implicated with a reduced cancer risk [ 2 , 2024 ] .
methyleugenol ( me ) belongs to the class of alkenylbenzenes and occurs in different plants such as nutmeg , pimento , lemongrass , tarragon , basil , star anise , and fennel [ 2527 ] .
it is also used as a flavoring agent in jellies , baked goods , beverages , sweets such us chewing gums or ice cream , and as a fragrance in cosmetic products .
there is a high interest in the safety evaluation of the food constituent me , since it has been classified as a genotoxic carcinogen by the scientific committee on food ( scf ) . in this study
we addressed the question whether the polyphenols chlorogenic acid ( cga ) , genistein ( gen ) , and egcg ( figure 1 ) inhibit hdac1 expression and/or hdac activity in intact human colon carcinoma cells .
furthermore , we include the genotoxic carcinogen me and its respective oxidative metabolites 1-hydroxymethyleugenol ( 1-oh - me ) , methyleugenol-2,3-epoxide ( mee ) , and 3-oxomethylisoeugenol ( 3-oxo - mie ) ( figure 1 ) in our testing to get a deeper understanding in mechanisms of action of potential chemopreventive food constituents in comparison to compounds with known adverse health effects .
dimethyl sulfoxide ( dmso ) , me , cga , and catalase were purchased from sigma - aldrich ( steinheim , germany ) .
the methyleugenol metabolites 1-oh - me , 3-oxo - mie , and mee were synthesized and purified according to the procedures previously described by our lab .
purities of me metabolites : 1-oh - me > 99.5% ; mee > 99.0% ; 3-oxo - mie > 97.5% ( with about 2.0% veratraldehyde ) , were all checked by 1h - nmr and hplc .
ht29 cells , a human colon adenocarcinoma cell line ( accession number acc 299 , deutsche sammlung von mikroorganismen und zellkultur ( dsmz ) , braunschweig , germany ) , were grown in dulbecco 's modified eagle 's medium ( dmem ) high glucose ( 4.5 g / l , invitrogen life technologies , karlsruhe , germany ) .
cell culture medium was supplemented with 10% fetal calf serum ( fcs ; paa , coelbe , austria ) and 1% penicillin / streptomycin ( invitrogen life technologies , karlsruhe , germany ) .
compounds were dissolved in dmso and added to the medium to yield a final dmso concentration of 0.5% ( v / v ) .
30,000 ( 24 h ) , 20,000 ( 48 h ) , or 8,000 ( 72 h ) ht29 cells per well were seeded into 24-well plates and allowed to grow for 24 h before treatment .
thereafter , cells were incubated with the respective test compound for 24 h , 48 h , or 72 h in culture medium .
effects on cell growth were determined according to the general method of skehan et al . modified according to kern et al . .
the fixed cells were stained with a 0.4% solution of sulforhodamine b. the dye was eluted with tris - buffer ( 10 mm , ph 10.0 ) and quantified spectrophotometrically at = 570 nm .
cell growth was measured as percent survival , determined by the number of treated cells over control cells 100 ( % t / c ) .
the wst-1 ( water soluble tetrazolium ) cell proliferation assay was performed according to the manufactures protocol ( roche diagnostics gmbh , mannheim , germany ) .
5,000 or 3,500 ht29 cells per well , respectively , were seeded into 96-well plates and allowed to grow for 24 h. v79 cells were treated with cga , egcg , or gen for 24 h or 48 h under fcs - containing conditions in the presence of catalase ( 100 u / ml ) . in each experiment a solvent control ( dmso 0.5% ) and a positive control igpal - ca630 ( 0.5% ) were included .
after treatment , medium was removed , cells were rinsed with 100 l / well pbs buffer , and then 100 l / well serum - free medium was added .
10 l / well of cell proliferation reagent wst-1 was added to the cells .
hdac enzyme activity was determined using hdac assay kit obtained from cayman chemical company ( ann arbor , mi , usa ) according to the manufactures protocol .
5,000 ht29 cells per well were seeded in 100 l culture medium in black , clear bottomed 96-well plates .
cells were incubated with cga , gen , or egcg in the presence of catalase to avoid hydrogen peroxide formation , or with me and its oxidative metabolites at the respective concentrations .
after 24 h the plate was centrifuged at 500 g for 5 minutes and the culture medium was aspirated .
200 l of diluted assay buffer ( kit constituent ) was added to each well , the plate was centrifuged at 500 g for 5 minutes , and the supernatant was aspirated .
thereafter , 90 l of culture medium or positive control ( recombinant hdac1 ) was added to noninhibited sample wells , and 80 l culture medium with 10 l trichostatin a was added to the inhibited samples , respectively .
the hdac reaction was initiated by adding 10 l of the diluted hdac substrate ( boc - n - acetyl - l - lysine-7-amino-4-methylcoumarin ) to each well .
cells were lysed by the addition of 50 l lysis / developer mixture ( kit constituent ) and the plate was shaken for 2 minutes .
after an incubation period for 15 minutes at 37c fluorescence was measured at an excitation wavelength of ex = 340360 nm and an emission wavelength of em = 440465 nm . a deacetylated standard ( kit constituent )
4.5 10 ht29 cells per petri dish were seeded in culture medium and allowed to grow for 48 h. cells were incubated with cga , gen , and egcg in the presence of catalase ( see above ) , or with me and its oxidative metabolites at respective concentrations .
after 24 h of incubation the culture medium was removed and the cells were washed with ice - cold phosphate buffered saline ( pbs ) for two times and abraded on ice with 200 l ripa buffer ( 65 mm tris , 154 mm nacl , 1 mm edta , 1% igepal - ca630 , ph 7.4 ) . thereafter the lysate was mixed for 1 minute and was centrifuged for 10 min ( 20,000 g , 4c ) .
the supernatant was separated by sds - page ( 12% polyacrylamide gel ) and the proteins were transferred onto a nitrocellulose membrane .
western blot analysis was performed using a goat polyclonal antibody against human hdac1 ( santa cruz , heidelberg , germany ) and an anti - goat igg - hrp conjugated secondary antibody ( santa cruz , heidelberg , germany ) .
the respective chemoluminescent signals ( lumi - glo , santa cruz , heidelberg , germany ) were analyzed using a lumi - imager ( roche , mannheim , germany ) .
growth inhibitory properties of methyleugenol and selected methyleugenol metabolites in ht29 cells were determined using the sulforhodamine b ( srb ) assay over 72 h. no growth inhibitory properties were observed for me and 1-oh - me using concentrations up to 100 m and 72 h of incubation ( table 1 ) .
whereas 3-oxo - mie reduced cell growth in a time and concentration - dependent manner ( figure 2(a ) ) with a 50% inhibitory concentration ( ic50-value ) of 100 14 m ( 72 h , table 1 ) . the oxidative metabolite mee was found to possess significant growth inhibitory properties without reaching an ic50-value ( figure 2(b ) , table 1 ) .
thus , growth inhibitory potency of the investigated alkenylbenzenes in ht29 cells ranked as follows : 3-oxo - mie > mee > 1-oh - me me .
cytotoxicity of cga , gen , and egcg was determined in the presence of catalase ( 100 u / ml ) to avoid hydrogen peroxide formation after an incubation period of 24 h or 48 h using the wst 1 ( water soluble tetrazolium salt ) assay .
cga , gen , and egcg did not exhibit cytotoxic effects up to the highest concentration implemented in our further investigations on hdac expression and activity ( data not shown ) . to address the question whether polyphenols or me and its respective metabolites modulate hdac activity in intact cells , ht29 cells were incubated with the test compounds for 24 h and enzyme activity was determined in an hdac cell - based activity assay kit .
the specific hdac inhibitor trichostatin a ( figure 1 ) was used as a positive control ( 80% inhibition at 2 m , figures 3(a ) and 3(b ) ) .
egcg and gen showed inhibitory effects on cellular hdac activity in a concentration - dependent manner ( figure 3(a ) ) .
the soy isoflavone gen diminished enzyme activity with an ic50-value of 97 18 m . the green tea catechin egcg inhibited hdac activity by about 50% at 100 m .
in contrast , cga exhibited no statistical significant effect on cellular hdac activity in ht29 cells up to 250 m ( figure 3(a ) ) . within the group of
alkenylbenzenes me and 1-oh - me did not affect hdac activity up to 100 m ( figure 3(b ) ) . however , the me - derived oxidative metabolites 3-oxo - mie and mee significantly inhibited cellular hdac activity at concentrations 50 m ( figure 3(b ) ) , reaching the following ic50-values : 54 20 m ( 3-oxo - mie ) and 38 3 m ( mee ) , respectively .
we further addressed the question whether the modulation of hdac activity by secondary plant constituents in ht29 cells is associated with changes in the amount of hdac protein .
the impact of the test compounds on hdac1 protein status in ht29 cells after 24 h of incubation was detected by western blot analysis using a goat polyclonal antibody against human hdac1 .
incubation of ht29 cells with cga increased the hdac1 protein level up to 250 m without statistical relevance ( figures 4(a ) and 4(b ) ) .
in contrast , the incubation of ht29 cells with gen resulted in a significant decrease of hdac1 protein at a concentration of 200 m ( figure 4(a ) ) .
the hdac1 status was significantly reduced at concentrations 50 m ( figure 4(a ) ) .
after treatment of ht29 cells with methyleugenol or the selected metabolites , no changes in the amount of hdac1 protein were detected by western blot analysis ( figures 4(c ) and 4(d ) ) .
dietary polyphenols have been demonstrated to exhibit cancer preventive and cancer therapeutic activity [ 18 , 19 , 34 ] .
the impact of polyphenols on enzymes involved in cell cycle regulation , apoptosis , invasion , metastasis , and angiogenesis has been associated with their beneficial health effect .
more recently , polyphenols have been found to alter gene expression by posttranslational modifications , including dna methylation or histone acetylation / deacetylation [ 8 , 20 , 35 , 36 ] . in the present study , egcg , the most abundant catechin in green tea ,
was shown to inhibit hdac activity and hdac1 protein expression in human colon carcinoma ht29 cells after 24 h of incubation ( figures 3(a ) and 4(a ) ) .
green tea polyphenols and notably egcg have been reported to diminish hdac activity , mrna expression of hdac1 and protein expression of class
the treatment of lncap human prostate cancer cells with egcg ( 520 m ) resulted in a dose- and time - dependent decrease of class i hdacs ( hdac1 , 2 , 3 , and 8) .
these results are in line with our findings that incubation with egcg ( 50 m ) significantly diminished the protein level of hdac1 in the human carcinoma cell line ht29 ( figures 4(a ) and 4(b ) ) , whereas a significant reduction of hdac activity was also determined but at higher concentrations ( 100 m , figure 3(a ) ) .
the soy isoflavone gen significantly inhibited hdac activity at concentrations 100 m ( figure 3(a ) ) .
hdac1 protein expression was significantly reduced after incubation with 200 m gen ( figures 4(a ) and 4(b ) ) .
therefore it can be assumed that other hdac isoforms are affected by gen leading to the more pronounced reduction of hdac activity which needs further investigations.gen and several other isoflavones have been recently described as hat activators and hdac inhibitors in esophageal , prostate , breast , and renal tumor cancer cell lines [ 24 , 3740 ] .
hdac activity was slightly decreased after the treatment with cga ( 250 m),whereas the protein level of hdac1 was shown to be moderately increased , but both effects were without statistical relevance .
hdac activity of a hela nuclear extract was inhibited by cga with an ic50-value of 375 m . to our knowledge
, modulation of hadc activity by cga in cellular systems has not been reported so far .
cga is one major polyphenol of our daily diet , which occurs in several food sources such as apples , potatoes , or coffee .
coffee consumers ingest about 1 g / d cga , whereas a daily intake of chlorogenic acid < 0.1 g / day has been reported for individuals who do not drink coffee [ 41 , 42 ]
. the average daily intake of soy isoflavones in the western diet has been estimated of about 13 mg / day , 3050 times lower than in asian countries .
a cup of green tea ( 200 ml ) contains about 150 mg egcg mainly consumed in asian countries .
several studies have demonstrated that only a small percentage of ingested gen , cga , or egcg appears in the blood with mean peak plasma concentration levels of nanomolar concentrations [ 4547 ] .
most of the published in vitro investigations , including our study , used the respective polyphenols at micromolar concentrations [ 2024 ] .
the rather poor bioavailability of polyphenols needs to be considered when we extrapolate results obtained in vitro to situations in vivo .
furthermore , it has to be mentioned that cytotoxic effects of the polyphenols egcg , gen , and cga in the implemented concentration range has been intensively discussed [ 32 , 33 , 48 , 49 ] .
different authors have reported a substantial hydrogen peroxide formation under cell culture conditions , resulting from the reaction of the used polyphenols with yet unknown culture media constituents , which influences the cellular effectiveness of the respective polyphenols [ 5055 ] .
egcg exhibited potent growth inhibitory properties , yet in our experiments in accordance with earlier results , the presence of catalase significantly attenuated this effect .
the addition of catalase resulted in a loss of any cytotoxic effects of egcg up to 100 m ( data not shown ) , suggesting that the formation of hydrogen peroxide acts as a major contributor of the reported cytotoxicity .
in contrast , no details on hydrogen peroxide formation after cell treatment with gen have been reported so far .
gen , in the absence of catalase , reduced dose - dependently ( 0100 m ) the cell viability of ht29 cells after 72 h of incubation , whereas in our experiments no cytotoxicity was measured up to 200 m ( 24 h ) neither in presence nor in absence of catalase ( data not shown ) . taken together , a hydrogen peroxide - scavenging system to in vitro cell culture assays using plant polyphenols seems to be needed . by the use of catalase ( 100 u / ml ) any artificial contribution of hydrogen peroxide to the inhibitory effects on hdac1 protein status and
only the two oxidative metabolites 3-oxo - mie and mee observed significant growth inhibitory properties on ht29 cells ( figure 2 , table 1 ) according to previous results of our group on v79 chinese hamster lung fibroblasts cells .
with respect to the metabolic activity of ht29 cells in contrast to v79 cells we have postulated a variably sensitivity against the test compounds , which was not the case .
furthermore , six oxidative me - metabolites , including the here - investigated ones , have been reported to reduce cell viability in metabolic competent primary rat hepatocytes by using two different assays .
the authors found the highest cytotoxicity for the main me - metabolite 1-hydroxymethyleugenol and the secondary metabolite 1-oxomethyleugenol , whereas me was found to be much less cytotoxic .
these results are in accordance with the studies of burkey et al . , where me only exhibited marginal cytotoxicity in rat hepatocytes at concentrations up to 3 mm .
the levels of hdac activity within cells can be altered via direct inhibition of the hdac enzyme and changes in hdac protein levels . in the study presented here , the metabolites 3-oxo - mie and mee
were firstly reported to potently diminish hdac enzyme activity ( figure 3(b ) ) without modulating the protein status of hdac1 .
further work will be needed to investigate whether the metabolites directly suppress hdac activity or whether protein expression of the other hdac isoforms will be suppressed .
furthermore , hdac inhibitors sensitize dna to exogenous genotoxic damage and induce the generation of reactive oxygen species . at least , hdac inhibitors could induce chromosome missegregation .
some dietary constituents have been reported to enhance dna damage and to affect hdac activity in cancer cells .
the glucosinolate sulforaphane induced dna double strand breaks in the human colon carcinoma cell line hct116 .
furthermore , hdac3 and hdac6 protein expression was decreased by sulforaphane in a time - dependent manner , leading to acetylation of histone h4 and tubulin , respectively . within the class of polyphenols egcg , gen , and quercetin ,
a flavonoid found in foods such as citrus fruit , apples , and onions , or resveratrol , has been characterized as hdac inhibitors with dna - damaging properties recently reviewed by .
additional studies are required to elucidate whether downregulation of dna repair or cell cycle regulating events may be involved in the dna damaging mechanisms of 3-oxo - mie and mee .
the present study shows that the polyphenols egcg and gen and the two me metabolites 3-oxo - mie and mee potently diminished the activity of hdac in intact colon carcinoma cells .
we further demonstrated that modulation of hdac activity is associated with the suppression of hdac1 protein status by polyphenols , whereas the me metabolites did not affect the protein level of hdac1 .
these results illustrate an interference of egcg and gen with epigenetic pathways which may contribute to the idea that dietary polyphenols have potentially chemopreventive effects .
furthermore , we show that via bioactivation of the prominent food carcinogen me , metabolites not only with potential genotoxic , but also with hdac inhibitory properties will be generated which may contribute to their dna - damaging properties . in summary ,
the results presented reveal that more investigations on the mechanism of action for future risk / benefit assessment of polyphenols and alkenylbenzenes will be necessary . | evidence has been provided that diet and environmental factors directly influence epigenetic mechanisms associated with cancer development in humans .
the inhibition of histone deacetylase ( hdac ) activity and the disruption of the hdac complex have been recognized as a potent strategy for cancer therapy and chemoprevention . in the present study
, we investigated whether selected plant constituents affect hdac activity or hdac1 protein status in the human colon carcinoma cell line ht29 .
the polyphenols ( )-epigallocatechin-3-gallate ( egcg ) and genistein ( gen ) as well as two oxidative methyleugenol ( me ) metabolites were shown to inhibit hdac activity in intact ht29 cells .
concomitantly , a significant decrease of the hdac1 protein level was observed after incubation with egcg and gen , whereas the investigated me metabolites did not affect hdac1 protein status . in conclusion ,
dietary compounds were found to possess promising hdac - inhibitory properties , contributing to epigenetic alterations in colon tumor cells , which should be taken into account in further risk / benefit assessments of polyphenols and alkenylbenzenes . |
the treatment of pressure sores is a challenge for the health care professionals because they are difficult to heal have tendency to recur , add significantly to the health care cost and are often compounded by significant medical illness .
the complications and the recurrence rates are the major problems in pressure sore reconstructions , which are reported variedly from 7% to 62% . it is widely accepted that invasive type 3 or 4 pressure sores require surgical intervention , because the conservative non - surgical therapy is extremely extended and increases the possibility of early recurrence . the myocutaneous flap was the first choice in pressure sore reconstruction , providing the theoretical advantages of eliminating the dead space because they are bulky , they have a good blood supply to overlying soft tissues , and they have superior resistance to infections . however thiessen et al . performed 37 muocutaneous flaps and 57 fasciocutaneous flaps in 94 pressure sores and after a mean follow - up of 3.1 years they found that complication and the recurrent rates were not associated with the type of the flap . in this study , we present our experience in pressure sore reconstruction using a recent fasciocutaneous flap , which is named reading man flap. the flap was first described in 2007 for the closure of skin defects in face , trunk , and extremities .
the name of the flap was given because its design resembles the silhouette of a man who is reading a book held in his hand .
until now there no references in the medical literature for use of this flap in pressure sore reconstruction .
over a period of 1 year we operated 16 patients , 11 men and 5 women .
the mean size of the defects after debridement was 8 cm 9 cm ( ranged from 3 cm 4 cm to 18 cm 15 cm ) [ table 1 ] .
the mean follow - up was 5 months ( 2 - 8 months ) which was admittedly short .
after adequate wound - bed preparation , infection control , and improvement of nutritional parameters , the surgery was scheduled .
they were placed in prone or lateral decubitus position depending upon the site of the pressure sore .
local infiltration ofand epinephrine 1:200.000 was followed by a thorough debridement of the calcified tissues , bursa , and bone ( the bony prominences were always flattened ) until viable tissues were encountered .
the finally defect in all cases was almost circular and measured again in order to design the reading man flap .
after determination of the relaxed skin tension lines in the defect area , we designed two skin flaps in an unequal z - plasty manner .
once its direction was decided , the central limb of the unequal z - plasty was drawn as an imaginary tangential line passing through the margin of the defect .
the length of the central limb of the z - plasty was designed to be 50% longer than the diameter of the circular defect .
beginning from the free end of this line another imaginary line is drawn with an angle of 60. then beginning from the other end of the central limb our third imaginary line was drawn with an angle of 45. the two skin flaps were elevated as fasciocutaneous flaps and one flap was moved to the defect and the other was transposed to cover the first flap 's donor site [ figure 1 ] .
( a ) an unequal z - plasty is drawn and created two flaps ( f1 , f2 ) .
the f1 flap is used for the defect closure whereas the f2 flap is transposed for closure of donor site ( b ) the final result after flaps transposition
after adequate wound - bed preparation , infection control , and improvement of nutritional parameters , the surgery was scheduled .
they were placed in prone or lateral decubitus position depending upon the site of the pressure sore .
local infiltration ofand epinephrine 1:200.000 was followed by a thorough debridement of the calcified tissues , bursa , and bone ( the bony prominences were always flattened ) until viable tissues were encountered .
the finally defect in all cases was almost circular and measured again in order to design the reading man flap .
after determination of the relaxed skin tension lines in the defect area , we designed two skin flaps in an unequal z - plasty manner .
once its direction was decided , the central limb of the unequal z - plasty was drawn as an imaginary tangential line passing through the margin of the defect .
the length of the central limb of the z - plasty was designed to be 50% longer than the diameter of the circular defect .
beginning from the free end of this line another imaginary line is drawn with an angle of 60. then beginning from the other end of the central limb our third imaginary line was drawn with an angle of 45. the two skin flaps were elevated as fasciocutaneous flaps and one flap was moved to the defect and the other was transposed to cover the first flap 's donor site [ figure 1 ] .
( a ) an unequal z - plasty is drawn and created two flaps ( f1 , f2 ) .
the f1 flap is used for the defect closure whereas the f2 flap is transposed for closure of donor site ( b ) the final result after flaps transposition
drains were used for 9 2 days . follow - up ranged from 2 to 8 months ( median 5 months ) , and none of the patients developed recurrences or required a second surgery during the follow - up [ figures 27 ] .
sacral pressure sore area ( 5 cm 5 cm ) after surgical debridement second postoperative day sacral pressure sore ( 12 cm 8 cm ) before surgical debridement with reading man flap design third postoperative day .
the pressure wound management demands a multidisciplinary approach . the goals of management are ( 1 ) prevention of complications , particularly invasive infections , related to the existing sore , ( 2 ) preventing the existing sore from getting larger , ( 3 ) preventing sores in other locations ; and if it is possible , ( 4 ) closure of the wound . for the invasive type pressure sores ( type 3 and 4 ) ,
in which there is full thickness tissue loss with or without exposed muscle , bones or tendons , surgery remains the best option . in these cases
attempt at healing by conservative treatment alone can be quite extended and increases the possibilities for early recurrence as the healing by secondary intention is usually resulting in unstable scars .
various myocutaneous or fasciocutaneous are used for repairing pressure sores , but in terms of lowest recurrent rate there is very little to choose between the two , and there are various other factors in the patient that contribute to recurrences .
the theoretical advantages of using muocutaneous flaps are ( 1 ) they can eliminate the dead space because they are bulky flaps , ( 2 ) they provide a well - vascularized and cushioning tissue over the a pressure bearing area . and their vascularity helps fighting infection at the local site .
however the long - term results and complications seem to be the same with the fasciocutaneous flaps because the deneurotized muscle becomes atrophic and loses its dynamic function and the ability to absorb the pressure .
thiessen et al . in their study showed that the complications and the recurrent rates were similar with myocutaneous and fasciocutaneous flaps .
yamamoto et al . reported that the use of the fasciocutaneous flap is expected to provide a better long - term result in surgical reconstruction of pressure sores than the myocutaneous or muscle flap .
lin et al . using a posterior - thigh fasciocutaneous flap for the treatment of ischial pressure sores in 12 patients had only two recurrences after 24 and 27 months .
in addition homma et al . suggested the use of posteromedial thigh fasciocutaneous flap for reconstruction of primary or recurrent ischial pressure ulcers .
the major advantage of fasciocutaneous flaps is the preservation of the underlying muscle , which is particularly important to ambulatory patients . in terms of skin defect size ,
it requires a simple and safe procedure with minimal invasion and preserves the underlying donor tissues for further reconstruction .
although the local fasciocutaneous flaps like the limberg flap has stable circulation , they are inappropriate for large skin defects because inappropriate wound tension occurs , leading to dehiscence . since the advent of perforator flap , several flap designs have been proposed for the coverage of sacral , ischial , and trochanteric pressure sores . however the lack of the simplicity of these flaps makes them not very attractive surgical option for many surgeons . in our cases
we used a local flap ( reading man flap ) , based on the z - plasty concept for pressure sore reconstruction .
the advantage of this flap compared to other local flaps such as limberg , banner , and dufourmentel ( 1 ) is that it results minimal distortion and displacement of the neighbouring mobile anatomic structures , so the defect closure is done with lesser tension and ( 2 ) the amount of additional healthy skin excision is less than that in the limberg flap .
however , the existence of osteomyelitis or big cavity in the ischical or trochanteric region is a contraindication for this flap as this flap is not able to fill the dead space .
we used the reading man flap in 16 patients with pressure sores in different anatomic locations and achieved wound close with minimal tension . in the postoperative period
there was no wound dehiscence , flap necrosis , haematoma , or infection and during our limited follow up we encountered no pressure sore recurrence . among the many surgical options for the reconstruction of pressure sore ,
the reading man flap is an easy , effective , and trustful alternative method . | background : the treatment of pressure sores represents a significant challenge to health care professionals . although , pressure wound management demands a multidisciplinary approach , soft tissue defects requiring reconstruction are often considered for surgical management .
myocutaneous and fasciocutaneous flaps can provide stable coverage of pressure sores.purpose:here , we describe our experience using a recent fasciocutaneous flap , which is named reading man flap , in sacral , ischial , and trochanteric pressure sores.materials and methods : during a period of 1 year the authors operated 16 patients , 11 men , and 5 women , using the reading man flap .
the ages of the patients ranged from 24 to 78 years .
the location of pressure sores was 8 sacral , 5 ischial , and 3 trochanteric pressure sores .
the mean size of pressure sores was 8 cm 9 cm.results:all pressure sores covered bt the reading man flap healed asymptomatically .
after follow - up of 2 - 8 months , no recurrences were encountered and no further surgical intervention was required.conclusion:the reading man flap was found to be a useful technique for the closure of pressure sore in different anatomic locations . the advantage of tension - free closure and the minimal additional healthy skin excision made this flap a useful tool in pressure sore reconstructions . |
the eosinophil granulocytes ( eg ) normally represent a small percentage of the leukocytes in blood , although they are much more numerous in the tissues .
they can destroy parasites , but they also have immune - regulating functions and they can be involved , for instance , in reshaping / remodeling the conjunctive tissue
. there has been registered an important progress lately regarding the research and knowledge on these fascinating but still enigmatic cells .
the sanguine eosinophilia ( se ) represents a paraclinical sign which is characteristic to parasitary diseases .
it is specifically associated with parasite tissue invasion and migration and the level of eosinophilia is usually proportional to the invaded tissue area .
conversely , the parasites which do not invade tissues , the protozoans , for instance , do not generally cause increased eosinophilia .
aim : the study of the frequency , level , and the absolute and relative values of the se , depending on the parasitary disease type .
the study group comprised a number of 2198 children , aged 0 - 16 years , among whom 2167 were admitted with various parasitary diseases in craiova clinics ( pediatrics ii , pediatrics surgery , contagious diseases ) over a period of 12 years and a number of 31 children with acquired toxoplasmosis who were admitted in the pediatric clinic of fundeni clinical institute in bucharest over a one - year - period . among the 2198 children in the study , 1226 had diseases caused by protozoans : 1195 intestinal giardiasis and 31 acquired toxoplasmosis ; 754 diseases caused by nematodes : 169 ascaridiasis , 470 oxyurasis , 23 trichocephalosis and 92 trichinellosis ; 50 caused by cestodes : 23 hydatidosis and 27 himenolepidosis ; 168 associated parasitoses .
medical history was studied for all admitted children , from which we extracted the paraclinical data : hemogram , coproparasitary examinations , imagistic exams , immunologic investigations ( t. elisa ) .
the relative values ( % ) of the e.g. were transformed into absolute values ( /mm ) , by reporting them to the total number of leukocytes .
depending on the eg values , we determined 3 levels of se : light se 400 1000 eg / mm mean se 1000 3000 eg / mm sanguine hyper - eosinophilia ( s.h.e . ) > 3000 eg / mm for processing the data , we used statistic - mathematical methods : arithmetic mean ( am ) and standard deviation ( sd ) .
among the 2198 children with parasitary diseases who formed our study group , 1486 ( 67.6% ) had a normal number of e.g./mm while 712 ( 32.4% ) had s.e./ s.h.e .. s.h.e .
was present in 24 children out of the total of 2198 children with parasitary diseases , representing 1.1% while s.e .
levels in the 712 children with s.e . : light s.e . in 586 children ( 82.3% ) , mean s.e . in 102 ( 14.3% ) and
sanguine hyper - eosinophilia s.h.e . in 24 ( 3.4% ) children ( table 1 ) .
the frequency of s.e . in the parasitary diseases was as follows : among the 1195 children with intestinal giardiasis , 328 ( 27.5% ) presented s.e . in the children with acquired toxoplasmosis , s.e .
was present in 10 children ( 32.2% ) out of 31 children . among the 169 children with ascaridiasis , 65 ( 38.5% ) presented s.e .
; among the 23 children with trichocephalosis , 16 of them ( 69.6% ) presented s.e . ; in the children with trichinellosis , 73 ( 79.3% ) out of 92 presented s.e . ;
among the 27 children with himenolepidosis , 9 of them ( 33.3% ) presented s.e .. in the children with associated parasitoses , s.e .
was present in 68 ( 40.5% ) out of 168 children ( figure 1 ) .
s.e . frequency in the children with parasitary disease the absolute and relative mean values of the s.e . in the children with parasitary diseases were : in intestinal giardiasis 658.48444.12 e.g./mm , 7.894.42 e.g.% respectively ; in toxoplasmosis 703.07475.77 e.g./mm , 7.85.48 e.g.% respectively ; in ascaridiasis 690.6450.4 e.g./mm , 8.064.53 e.g.% respectively ; in oxyurasis 710.06506.17 e.g./mm , 7.985.25 e.g.% respectively ; in trichocephalosis 822.18484.87 e.g./mm , 11.187.23 e.g.% respectively ; in trichinellosis 3058.973532.67 e.g./mm , 21.7914.5 e.g.% respectively ; in hydatidosis 833.09582.8 e.g./mm , 10.75.48 e.g.% respectively ; in himenolepidosis 600.35116.28 e.g./mm , 6.882.08 e.g.% respectively ; in associated parasitoses 694.67370.59 e.g./mm , 8.634.28 e.g.% respectively ( fig.2 ) absolute and relative mean values of s.e . in parasitary diseases the absolute and relative maximum values of the s.e .
were as follows : in giardiasis 5548 e.g./mm , 38 e.g.% respectively ; in toxoplasmosis 2369 e.g./mm , 23 e.g.% respectively ; in ascaridiasis 5360 e.g./mm , 28 e.g.% respectively ; in oxyurasis 3120 e.g./mm , 41 e.g.% respectively ; in trichocephalosis 2450 e.g./mm , 35 e.g.% respectively ; in trichinellosis 15741 e.g .. /mm , 58 e.g.% respectively ; in hydatidosis 2300 e.g./mm , 23 e.g.% respectively ; in himenolepidosis 900 e.g./mm , 12 e.g.% respectively ; in associated parasitoses 1960 e.g./mm , 26 e.g.% respectively ( fig.3 ) absolute and relative maximum values of s.e . in parasitary diseases
one can notice that most of the children with parasitary diseases ( 82.3% ) presented light s.e
s.e . registered the highest frequency ( 79.3% ) in the children with trichinellosis , a parasitosis which is known to be accompanied by s.e . , according to the laws of parasitary eosinophilia of bonin , moretti and bertrand .
frequency was also increased in the children with trichocephalosis ( 69.6% ) , a parasitosis which , according to the specialty literature , is accompanied by s.e . , constantly met in children .
s.e . registered the lowest frequency in intestinal giardiasis ( 27.5% ) and oxyurasis ( 28.1% ) , parasitoses which , according to the laws of parasitary eosinophilia , are not accompanied by s.e . .
the newest data describes the presence of s.e . in these parasitoses , too , within variable percentages .
the highest mean value of the absolute and relative s.e . was encountered in trichinellosis ( 3058.97 e.g./mm3 , 21.79 e.g.% ) , one of the parasitary diseases accompanied by s.e .
the mean values of s.e . were the lowest in the children with himenolepidosis ( 600.35 e.g./mm , 6.88 e.g.% ) but also in the children with intestinal giardiasis ( 658.48 e.g./mm , 7.89 e.g.% ) .
in himenolepidosis , s.e . has moderate values 5% - 10% up to 15% and it is encountered in approximately one third of the patients .
the presence of s.e . in giardiasis triggered numerous discussions in the last few years .
there are authors who question the presence of eosinophilic properties for the protozoa , particularly for the giardiasis .
other authors present numerous cases of giardiasis accompanied by eosinophilia . the highest absolute and relative value was registered in a child with trichinellosis ( 15741 e.g./mm , 58 e.g.% ) .
high absolute and relative values were also registered in giardiasis ( 5548 e.g./mm , 38 e.g.% , respectively ) and in oxyurasis ( 3120 e.g./mm , 41 e.g.% , respectively ) .
is mentioned in the specialty literature and it is partly explained through / by the intensity of the parasitary infestation , on account of the parasite s ability to penetrate the tissues , through the specific way of the human body to respond to the parasitary aggression .
another explanation could be the fact that the study group consisted in a great number of children with giardiasis and oxyurasis and by the fact that these children were not further investigated in order to decide upon another possible cause for s.e . and s.h.e .
; we should also take into consideration a laboratory error , given the fact that the children never came again for a subsequent control to repeat the hemogram .
the lowest frequency was registered in oxyurasis ( 28.1% ) and in giardiasis ( 27.5% ) .
the highest mean value was registered in trichinellosis ( 3058.97 e.g / mm , 21.79 e.g.% ) .
the lowest mean values were registered in intestinal giardiasis ( 658.48 e.g./mm , 7.89 e.g.% ) and in himenolepidosis ( 600.35 e.g./mm , 6.88 e.g.% ) . | the authors carried out a retrospective study on the frequency , levels and relative and absolute mean values of sanguine eosinophily in children admitted with various parasitary diseases within the sanitary units in craiova and in the pediatric clinic of fundeni clinical institute , bucharest , over a period of 12 years .
the study group consisted of 2,198 children , aged 0 - 16 years : 1,226 with diseases caused by protozoa
1,195 intestinal giardiasis and 31 acquired toxoplasmosis ; 754 with diseases caused by nematodes - 169 ascaridiasis , 470 oxyurasis , 23 trichocephalosis and 92 trichinellosis ; 50 with diseases caused by cestodes - 23 hydatidosis and 27 himenolepidosis ; 168 with different associated parasitoses . for processing the data we used statistical - mathematical methods : arithmetic mean ( am ) and standard deviation ( sd ) . |
carcinoma in situ of the breast is defined as abnormal proliferation of epithelial cells that do not trespass the basal membrane of the breast ductal or lobular system and consist of a heterogeneous group with different types of histology and also different prognosis .
the incidence of ductal carcinoma in situ ( dcis ) has increased significantly in all parts of the world including the netherlands , mainly due to the introduction of breast cancer screening .
few treated patients will ultimately die of breast cancer ; however , despite the relatively benign nature of dcis , patients commonly undergo mastectomy [ 24 ] .
the risks of overdiagnosis and overtreatment have been discussed in several studies [ 2 , 3 , 5 ] .
nonetheless , some patients with dcis have a less benign course than other patients , and it is still not possible to identify which dcis lesions will progress to invasive carcinoma and in what time interval . besides , although dcis is thought of as an early - stage cancer , lesions can be quite large .
most clinical series have focused on the risk of breast cancer recurrence , rather than risk of death per se .
population - based reports of actual deaths from breast cancer in women with dcis are scarce , but show little excess mortality [ 7 , 8 ] .
the mass mammographic screening program in the netherlands started in 1990/1991 for females aged 5070 years ; in 1997 the upper age limit of the screening program was increased to 75 years .
the aim of this study was to assess the incidence and treatment of patients with dcis in the netherlands from 1997 to 2005 and to calculate the number of observed deaths versus the number of expected deaths based on the general population to estimate the excess mortality risk of patients diagnosed with dcis .
palga , the nationwide dutch network and registry of histo- and cytopathology , regularly submits reports of all diagnosed malignancies to the regional cancer registries .
the national hospital discharge databank , which receives discharge diagnoses of admitted patients from all dutch hospitals , completes case ascertainment .
trained cancer registry personnel collect data on diagnosis , staging , and treatment from the medical records , including pathology and surgery reports , using the registration and coding manual of the dutch association of comprehensive cancer centers .
all data from the regional cancer registries are merged into the netherlands cancer registry ( ncr ) . from the ncr database ,
adult female patients with dcis diagnosed between 1997 and 2005 were selected ( n = 8421 ) .
histopathology was according to the national protocols in the netherlands ( http://www.oncoline.nl/ ) ; central review of the histopathology was not performed .
dcis was defined according to these protocols , and microinvasion ( t1mi ) was not included .
age was divided into younger than 50 , 5064 , 6575 , and 75 years and older where the first and last groups were not invited for screening in the selected period .
changes over time in treatment were studied using chi - square tests or linear regression analysis .
vital status was established directly from the patient 's medical record or , in case of missing values through linkage of cancer registry data with the municipal population registries which record information on their inhabitant 's vital status .
as cause of death is not known in these cancer registry data , we used relative mortality .
relative mortality for 10 years of follow - up in the cohort was calculated by dividing observed mortality in the cohort at 10 years and expected mortality .
expected mortality was estimated based on the corresponding ( age , sex , and year ) general population ( national life tables ) .
mortality was stratified for age ( to assess differences in young and elderly patients ) and treatment .
the aim of the stratification in treatments was not to compare treatments between strata as this would not be possible due to confounding by indication .
instead , we aimed to assess excess mortality over strata for each surgical treatment group .
overall , almost half of all dcis was diagnosed in patients aged 5064 years .
figure 1 shows the incidence per 100 000 in the netherlands over the period 19972005 .
the incidence for patients under 50 years remained stable ( range 3.14.1 per 100 000 ) .
incidence for patients aged 75 years and older remained stable around 12 per 100 000 ( range 11.713.7 per 100 000 ) .
the incidence slightly increased for those aged 5064 years from 37.8 to 41.0 per 100 000 and almost doubled for the age group 6674 from 24.4 to 44.6 per 100 000 .
table 2 shows the treatment for patients with dcis in the netherlands according to age and period of diagnosis .
patients younger than 50 years often underwent mastectomy ( range 55.7% to 60.5% ) or breast - conserving surgery ( range 38.9% to 46.3% ) . over all the years , only 0.6% did not undergo surgery .
patients aged 5064 and 6574 more often underwent breast - conserving surgery , and this proportion significantly increased over time ( p < 0.001 ) . for the elderly patients 75 of age , 7.6% did not undergo surgery , half ( 50.4% ) underwent mastectomy and 42.0% underwent breast - conserving surgery .
although there was a trend towards more breast - conserving surgery over time , this trend did not reach statistical significantly ( p = 0.07 ) .
for all ages , adjuvant radiotherapy after breast - conserving surgery increased over the years ( all p values < 0.001 ) . in the last period ( 20032005 ) the highest percentage of women receiving radiotherapy was in the age 6575 ( 82.4% ) and the lowest in the elderly of 75 years and older ( 51.9% ) .
radiotherapy after mastectomy was performed in 3.4% for the patients younger than 50 years and increased over time from 2.0% to 5.6% ( p = 0.004 ) . in the other age groups , the proportion of patients undergoing radiotherapy after mastectomy was lower ( 2.2% for 5064 years , 2.4% for 6575 , and 1.2% for the patients aged 75 years and older , resp . ) and did not change significantly over time .
table 3 shows the observed mortality , the expected mortality based on the general population , and the excess mortality as the ratio of the observed and expected mortality according to age and treatment ( patients who received no surgery excluded ) . as radiotherapy
after mastectomy was rarely given , mastectomy with or without radiotherapy were merged . in patients who underwent breast - conserving surgery ( with or without radiotherapy )
for the younger patients who underwent mastectomy , a significant relative mortality was recorded ( 2.6 ; p < 0.001 )
. for all strata of patients over the age of 50 years who underwent mastectomy , observed and expected mortality were close resulting in a relative mortality of around 1.0 .
overall , all surgically treated patients aged 50 years and older experienced no excess mortality due to dcis ( ratio of 1.0 ) .
all ages combined , 704 deaths within 10 years were observed versus 692.1 expected based on the general population with a ratio of 1.0 expressing no excess mortality of dcis in the netherlands .
due to the introduction of breast cancer screening , incidence of dcis has increased dramatically in the last years . despite the increasing incidence
not many population - based reports are available that report mortality in this group of women .
the present population - based study of almost 8500 patients in the netherlands diagnosed between 19972005 shows that excess mortality was observed for patients younger than 50 years .
however , no excess mortality in surgically treated women over 50 years with dcis was observed .
this means that after the diagnosis and treatment of dcis the women experienced a similar mortality as age and year matched women in the general population . understanding the care received by women with dcis is important since it is highly curable , its incidence is rising ( from 4.9 ( 1989 ) to 18.6 ( 2008 ) per 100 000 ) , and it is often detected in otherwise healthy women and there is a possibility of overtreatment .
overall , 45% of the women in the netherlands underwent mastectomy for dcis . in many such patients
, mastectomy may have been medically appropriate , based on patient preferences or the underlying practice of individual surgeons or institutions .
the reasons for this are unclear , but the result is probably explained by patients who are unfit for surgery due to many comorbidities or patient preferences . although mastectomy results in a cure rate approaching 100% , this may be overtreatment for some patients , particularly those with small , mammographically detected lesions
. moreover , there are no randomized studies demonstrating that mastectomy is better than conservative surgery followed by radiotherapy for patients with dcis .
the role of radiotherapy after breast - conserving surgery is supported by large randomized studies for improvement of local control ; however , none of these studies showed an improvement in survival or decrease in the risk of distant metastases [ 1 , 1214 ] .
a recent overview of the randomized trials of radiotherapy in dcis showed that radiotherapy reduced the absolute 10-year risk of ipsilateral recurrent dcis by 8.4% and of ipsilateral invasive cancer by 8.5% ( both p < 0.00001 ) .
however , after 10 years of follow - up there was no significant effect on breast cancer mortality , mortality from causes other than breast cancer , or overall mortality .
in the present study administration of adjuvant radiotherapy after breast - conserving surgery increased through the years for all ages , however , remained lower for the elderly aged 75 years and older .
the identification of low risk groups within the elderly patients in whom radiotherapy can be omitted as well as the development of newer radiation techniques should be a priority . in the present study , data concerning the cause of deaths was not available .
however , we were able to estimate the excess mortality by comparing the mortality in the cohort to mortality in the general population ( matched for sex , year , and age ) .
the present study showed no excess mortality as compared to the general population in patients who underwent surgery .
patients who were not surgically treated were excluded from this analysis as they are probably considered to frail and by such are not comparable to the general population .
as far as we know , there is only one published population - based report of the likelihood of breast cancer death among women with dcis ( n = 7072 ) .
breast cancer deaths were assessed in two groups based on the introduction of screening mammography ( 19781983 and 19841989 ) . among women diagnosed in the early period , 1.5% died of breast cancer within 5 years and 3.4% in 10 years ; among the women diagnosed in the latter period 0.7% died of breast cancer within 5 years and 1.9% in 10 years .
the study of ernster et al . reported a 10-year standardized mortality ratio of 1.9 ( 95% ci 1.22.3 ) .
direct comparison of the numbers is however not possible as the study of ernster calculated the standardized mortality ratio and the present study the estimated excess ( relative ) mortality .
the latest numbers in the study of ernster et al . were from 19841989 while the present study describes 19972005 .
diagnostic precision ( by introduction of the digital mammography ) has probably improved in that period so that patients are less likely to have unrecognized microinvasive breast cancer or the proportion of detected dcis with low malignant potential has increased .
this could also possibly reduce the excess mortality due to breast cancer in our cohort as compared to ernster et al .
as almost all women were treated surgically , it is impossible to know from these data the extent to which the low excess mortality from breast cancer among women with dcis results from effective treatment or reflects the relative benign nature of the disease or probably both
. remarkably , we did find an excess mortality in the younger patients ( < 50 years ) treated with mastectomy .
it could be that a large proportion of this group are brca1/2 carriers ; however we have no information to verify this .
mortality was stratified for age ( to assess differences in young and elderly patients ) and treatment .
the aim of the stratification in treatments was not to compare treatments between strata as this would not be possible due to confounding by indication .
instead , we aimed to assess excess mortality over strata for each surgical treatment group . in the present study we had no data concerning recurrences in individual patients .
however , despite the fact that some of these women would have experienced a recurrence , excess mortality due to that recurrence is presumably low .
approximately half of the recurrences are not invasive and can be cured with additional surgery .
furthermore , patients who present with invasive cancer have also a low risk of distant disease . for
some ages excess mortality was below 1.0 ( observed mortality did not exceed expected mortality ) indicating that women with dcis represent a generally healthy subgroup of the population which was also confirmed in the study of ernster et al . .
women who present for mammography may have healthier lifestyles than other women ; studies have shown that women who undergo regular screening are more socioeconomically advantaged and practice more preventive health behaviors than women who do not [ 3 , 16 , 17 ] .
moreover , breast cancer is more often diagnosed in women with a higher socioeconomic background . in conclusion ,
the present population - based study of almost 8500 patients in the netherlands shows no excess mortality in surgically treated women over 50 years with dcis ; observed and expected mortality were almost equal resulting in a relative mortality due to the dcis of 1.0 . | background .
the incidence of ductal carcinoma in situ ( dcis ) has increased at a fast rate.the aim of this study was to assess the incidence and treatment in the netherlands and estimate the excess mortality risk of dcis .
methods . from the netherlands cancer registry , adult female patients ( diagnosed 19972005 ) with dcis were selected .
treatment was described according to age .
relative mortality at 10 years of follow - up was calculated by dividing observed mortality over expected mortality .
expected mortality was calculated using the matched dutch general population . results .
overall , 8421 patients were included in this study . for patients
aged 5064 , and 6574 an increase in breast - conserving surgery was observed over time ( p < 0.001 ) . for patients over 75 years of age
, 8.0% did not undergo surgery ; this percentage remained stable over time ( p = 0.07 ) .
overall , treated patients aged > 50 years experienced no excess mortality regardless of treatment ( relative mortality 1.0 ) .
conclusion .
the present population - based study of almost 8500 patients showed no excess mortality in surgically treated women over 50 years with dcis . |
informed consent is a process of communication between a patient and physician that results in the patient 's authorization or agreement to undergo a specific medical intervention . for the clinician , this process is both an ethical obligation as well as a legal requirement .
there are three key elements of an appropriate informed consent process : the patient ( or the surrogate ) should have the capacity to decide ; sufficient information should be provided on which to base that decision , and the decision reached should be free from coercion .
professional guidelines in the specialty of anesthesia require that express informed consent should be obtained for any procedure that carries a material risk ( a risk which a reasonable person in the patient 's position would be likely to attach significance ) . a working party of the association of anaesthetists of great britain and ireland ( aagbi ) , revisited the issue of consent and anesthesia in 2006 and reiterated , among other things , that express verbal consent is sufficient for anesthesia provided that the anesthetist documents both the patient 's decision as well as the discussions which led to the decision .
signed form , which in itself may not increase the validity of the consent .
the role and usefulness of separate consent forms for anesthesia continue to be a subject of debate
. proponents of separate written consent argue that from a liability standpoint a well - thought - out anesthesia - specific consent form is the method of documentation that offers the best level of protection in cases of malpractice litigation . apart from its value as documentary evidence , in theory , the presentation of a consent form may act as a stimulus for an active discussion of risks , thereby facilitating patient 's unique and legitimate concerns .
a well - written consent document may also serve as a reminder to the anesthetist of the issues which need to be addressed to obtain an acceptable informed consent .
notably , a review of the medical literature does not identify any study which investigates the hypothesis that a requirement for signed consent for anesthesia may serve as a catalyst for an enhanced informed consent process .
the documentation of consent for anesthesia in majority of hospitals of trinidad , relies on a simple clause in the surgical consent document which states that the patient consents to the operation and to such general or other anesthetic and such further or alternative procedures as may be necessary .
documents are administered by a member of the surgical team ( usually a house officer ) and are often signed prior to any contact with the anesthetist .
a discussion between the patient and their anesthetist regarding their anesthesia care may subsequently occur to varying degrees during the preoperative anesthetic visit but a record of this discussion is rarely made except in high - risk cases or sometimes where regional anesthesia is proposed .
the reliance on a catch - all phrase regarding anesthesia on the surgical consent document places no apparent legal or institutional obligation on the anesthetist in this setting to engage in a proper informed consent discussion with the patient and it is a reasonable inference that if the anesthetist was required to obtain separate signed consent it would increase the likelihood that this discussion does occur and would also be documented adequately . with this background , this study sought to compare the efficacy of a separate informed consent process for anesthesia services at our tertiary care teaching hospital and the factors which may influence the consent process .
this prospective study was conducted on the pre- and postoperative wards of a tertiary care teaching hospital during a 3 month - period . approval to conduct this study
was received from the ethics committee of the university and from the medical director of the hospital .
adult patients undergoing elective surgery during the study period who consented to participate were eligible for inclusion in the study .
patients were excluded if :
they were anesthetized / consented by the investigator.they were unable to communicate comfortably during the postoperative period for any reason ( e.g. , respiratory distress , confusion / disorientation , tracheal intubation etc.).they declined to participate .
they were unable to communicate comfortably during the postoperative period for any reason ( e.g. , respiratory distress , confusion / disorientation , tracheal intubation etc . ) .
all the subjects enrolled in the study were informed of the following :
the nature and purpose of the study.that no identifying data would be recorded , and no communication would take place between the investigator and the attending anesthetist or surgeon with regards to the interview.that their care would be unaffected whether they agreed to participate or not .
the nature and purpose of the study . that no identifying data would be recorded , and no communication would take place between the investigator and the attending anesthetist or surgeon with regards to the interview . that their care would be unaffected whether they agreed to participate or not .
the subjects were allocated into two groups : group a and group b randomly by computer allocation .
group a included all patients who were required to sign the hospital 's consent for operation
consent for anesthesia form [ appendix 1 ] in addition to the consent for operation form .
the anesthetists who participated in the study , anesthetized patients in both groups ; the only difference being the separate consent form .
all the participating subjects were approached by the investigator during the postoperative period at the earliest time at which they were comfortable enough to participate , but not later than 4 postoperative day . the majority of the interviews lasted for < 10 min .
the type of anesthesia and the grade of the anesthetist obtaining consent were determined from the anesthetic record .
demographic data recorded were age , gender , and level of education ( classified as primary and below , secondary , and tertiary or above ) .
other case - specific data obtained were type of anesthesia , grade of anesthetist taking consent , and whether a consent for anesthesia
the following eight elements of the informed consent process considered to be desirable by the working party of the aagbi in their 2006 publication entitled consent and anesthesia were investigated :
permission.absence of coercion.an appreciation of the nature and purpose of the proposed anesthetic procedures.patients satisfaction with information provided on common side effects of the proposed anesthetic procedures.patients satisfaction with information provided on rare but serious complications of the proposed anesthetic procedures.discussion of alternatives.provision of information about postoperative care and pain control.opportunity to ask questions .
patients satisfaction with information provided on rare but serious complications of the proposed anesthetic procedures .
each of the above elements was listed as a statement on the questionnaire with each patient being asked to state their agreement with the statement on a 5-point likert scale ranging from strongly disagree to strongly agree .
a cumulative score for each patient 's responses was calculated , with a maximum possible score of 40 and a minimum possible score of 5 .
data collected were coded and entered in microsoft excel. analysis was done using statistical package for social sciences ( spss ) version-12 ( spss inc . , chicago , illinois , usa ) .
mann - whitney u - test was used to compare the adequacy of consent index between patient groups a and b , as well as gender , level of education , or grade of anesthetist administering the consent process .
chi - square analysis was used to detect differences in responses between group a and group b for each of the eight individual informed consent issues addressed .
demographic data recorded were age , gender , and level of education ( classified as primary and below , secondary , and tertiary or above ) .
other case - specific data obtained were type of anesthesia , grade of anesthetist taking consent , and whether a consent for anesthesia
the following eight elements of the informed consent process considered to be desirable by the working party of the aagbi in their 2006 publication entitled consent and anesthesia were investigated :
permission.absence of coercion.an appreciation of the nature and purpose of the proposed anesthetic procedures.patients satisfaction with information provided on common side effects of the proposed anesthetic procedures.patients satisfaction with information provided on rare but serious complications of the proposed anesthetic procedures.discussion of alternatives.provision of information about postoperative care and pain control.opportunity to ask questions .
patients satisfaction with information provided on rare but serious complications of the proposed anesthetic procedures .
each of the above elements was listed as a statement on the questionnaire with each patient being asked to state their agreement with the statement on a 5-point likert scale ranging from strongly disagree to strongly agree .
a cumulative score for each patient 's responses was calculated , with a maximum possible score of 40 and a minimum possible score of 5 .
data collected were coded and entered in microsoft excel. analysis was done using statistical package for social sciences ( spss ) version-12 ( spss inc . , chicago , illinois , usa ) .
mann - whitney u - test was used to compare the adequacy of consent index between patient groups a and b , as well as gender , level of education , or grade of anesthetist administering the consent process .
chi - square analysis was used to detect differences in responses between group a and group b for each of the eight individual informed consent issues addressed .
seventy - eight males ( 39% ) and 122 females ( 61% ) consented to participate in the study .
one hundred and sixty - five patients ( 82.5% ) received general anesthesia , 29 ( 14.5% ) had central neuraxial blocks , and 6 ( 3% ) had peripheral nerve blocks .
the majority of the subjects had attended secondary school ( 55% ) , 29% achieved a level of education of primary and below and 16% achieved a tertiary level education .
the grades of anesthetists involved in the consent process were house officers in 72% of cases , registrars in 21.5% and consultants in 6.5% .
one hundred patients belonged to group a having signed the hospital 's consent for operation
consent for anesthesia form in addition to the consent for operation form .
summary of population and group demographics all patients ( 100% ) indicated that their anesthetist(s ) had their permission to proceed with their anesthesia care .
overall 97.5% indicated that they did not feel pressured or rushed into giving permission ( 99% in group a ; 96% in group b ) .
84% of the group a patients and 93% of the group b patients agreed that they understood the nature and purpose of the intended anesthesia procedures .
notably , 60% of the group a patients did not feel that they were adequately informed about common side effects compared to 27% of group b patients . with respect to rare but serious side effects
, 73% of group a patients and 54% of group b patients felt that information provided was inadequate .
a summary of the responses to the eight - item questionnaire is given in table 2 .
responses to statements regarding the informed consent process the adequacy of consent index scores in group a ranged from 16 to 39 , with a mean of 27.9 , standard deviation ( sd ) 5.2 . in group
b , the adequacy of consent index score ranged from 17 to 38 , with a mean of 30.6 ( sd ) 4.6 .
mann - whitney u - test showed a statistically significant improvement in adequacy of consent index scores when separate written consent for anesthesia was obtained ( p < 0.001 ) .
the comparison of the adequacy of consent index scores within the group b patients with respect to gender , level of education and grade of anesthetist did not show any significant difference among subjects according to gender or level of education .
the mean adequacy of consent index was higher among patients who were consented by a registrar or smo ( 32.2 ) compared to a house officer ( 30 ) , but the p value was 0.05 ( borderline at the set level of significance ) .
chi - square analysis identified only three aspects of the informed consent process which were positively affected by the use of separate written consent for anesthesia .
these were patients ' perception of the adequacy of information provided about commonly occurring or expected side effects ( p < 0.001 ) , information about rare but serious complications of the proposed anesthetic procedures ( p = 0.008 ) and the patients ' understanding of the nature and purpose of the intended anesthetic procedures ( p = 0.04 ) .
there was almost total agreement among both groups that permission was given without undue pressure and that they had sufficient opportunity to ask questions .
the primary finding of this study is that in our public hospital setting , the informed consent process may be better when a separate written consent was obtained for anesthesia as estimated by the adequacy of consent index .
anesthesia procedures are clearly different from surgical procedures in their nature , purpose , and risk profiles .
it is therefore logical that if informed consent for anesthesia procedures is obtained independently , and further , if it is obtained by a clinician ( anesthetist ) capable of formulating and discussing the anesthesia care plan ( vis - - vis its ' risks , benefits , and alternatives ) , the patient is likely to have a better information .
the aagbi has advised that a signed consent form is not necessary for anesthesia procedures because it felt that emphasis should be placed on the process of informed consent rather than on obtaining a signature on a form .
consent forms are often too complex for the average patient to read and understand and , in fact , many patients sign consent forms without reading or understanding them .
another criticism is that many consent forms appear to be constructed to protect hospitals and caregivers from liability rather than clarify information about procedures or aid patients in decision - making .
these authors have suggested that the legal appearance and content of these consent forms are likely to inhibit , if not counteract , the goals of informed consent by adding to the perception that institutional protection takes precedence over patient care . despite these myriad concerns which question the value of consent forms , this study has demonstrated that the use of a consent form for anesthesia improved the adequacy of the informed consent process .
it is quite likely that in this setting ( where the institutional obligation for consent to anesthesia is fulfilled by a signature on the surgical consent document ) a requirement to obtain separate written consent serves as an essential stimulus for a discussion between the anesthetist and the patient about the anesthesia care plan .
this idea that a consent form may aid the consent process by acting as a prompt or a stimulus to an active discussion about treatment options has been supported by several authors .
apart from the possible role as a catalyst to the process , the form itself may serve as a reminder or a checklist of the elements of the informed consent process which need to be addressed .
another probable reason why the use of separate written consent helped rather than hindered the informed consent process in this study may be that the consent for anesthesia form was kept very simple , excluding details about the anesthetic techniques and risks that may have made the form difficult to understand .
the onus therefore remained on the anesthetist to provide the patient with the information necessary for the consent to be informed .
this approach of not providing detailed information on the form itself reduces the chances of the anesthetist just giving the patient the form to read and sign and thereby using the form as a substitute for the process .
the fact that the anesthetist necessarily remained the source of the information would have also hypothetically allowed the information to be tailored to the education level of the patient .
this may explain why no statistically significant relationship was found between educational level and adequacy of consent .
notwithstanding the fact that the use of separate written consent enhanced the overall adequacy of the informed consent process , several areas were identified where improvements are still needed . as much as 55% of patients who signed the anesthetic consent form did not think that they were adequately informed about rare but serious complications of the proposed anesthetic procedures .
one justification used in the past for the withholding of information is the notion that patient apprehension caused by frightening information results in raised catecholamine levels which make it more difficult to anesthetize the patient .
stanley et al . demonstrated that patients ' anxiety levels were unaltered by the provision of additional detailed verbal and/or written information .
shimoda et al . went a step further and showed that patients who had anxiety about anesthesia before an operation indicated a greater need for detailed printed information compared with those without anxiety .
furthermore , several other studies investigating patients ' desire for information perioperatively have found that , in general , there is a desire for more rather than less information .
some practitioners may withhold information because they feel that it may deter a patient from undergoing a beneficial procedure .
the aagbi in their 2006 publication titled consent and anesthesia argued in favor of the converse , that any information which might lead a patient to cancel or defer a procedure should be considered significant .
another major shortcoming identified in the informed consent process was the infrequency of discussion about alternatives to the proposed anesthetic procedures .
sixty - seven percent of patients who signed the consent for anesthesia form indicated that no discussion took place about the possibility of alternative anesthetic techniques . in our setting , with anesthetists often meet their patients on the day of surgery , hence the anesthetist primarily discusses what he / she intends to do , meeting the lower standard of legal acceptability but at the same time sacrificing the ideals of patient autonomy and shared decision making .
this compromise is unfortunate because it has been shown that the preservation of patient autonomy is associated with improved patient satisfaction and more favorable medical outcomes .
the issue of postoperative pain control was another area that was not satisfactorily discussed by the anesthetists who obtained consent , with approximately 55% of patients overall indicating dissatisfaction with the information provided .
barneschi et al . reported that the desire for information about pain in their study was particularly high ( 85% ) .
this underscores the relevance of pain and analgesia as an issue in the informed consent process . although the results suggest that the information provided to patients was not as complete as it should be , patients apparently opted not to utilize the opportunities that they were given to ask questions .
crawford - sykes and hambleton reported that although jamaican patients expressed a desire for information concerning anesthesia and surgery , they did not regard it as their right . a study conducted in
the uk revealed that nearly all women before obstetric anesthesia ( 82 - 94% ) wished to know about common , less severe side effects , while a substantial majority ( 70 - 77% ) also wished to know about rarer but more severe complications , such as permanent neurological deficit , meningitis , and high spinal block .
our study established a better knowledge of this aspect of anesthesia when a separate consent form was used .
the significance of the findings of this study should be however interpreted within the context of the limitations of the study .
first , the adequacy of consent index was devised and used for the first time in this study and therefore it was not previously validated .
although eight different essential aspects of the informed consent process were assessed with this instrument , there are several other aspects which were not included .
the most important one is probably the extent to which the patient was allowed to share in the decision - making process .
with respect to information provided to the patient about material risks , patients were asked if they felt that they were adequately informed .
one problem with this approach is that it is subjective in nature , and a patient who claims to be satisfied may find other risks relevant if they were made aware of them .
an alternative approach taken by other researchers was to measure objectively patients ' recall and understanding of information provided .
with respect to the methodology of this study , it can be argued that the introduction of a consent form for anesthesia on a trial basis , with the implication that there will be an assessment of the new measure , may have led anesthetists to artificially alter their practice , which could have introduced a desirability bias .
although this consideration was a real possibility , many anesthetists were not made aware of any details of the planned evaluation .
it has been shown that patients are best informed immediately after signing the consent form and from then on there is a deterioration of the recall of information .
the consequence of this is that patients may have forgotten some of the details about what they were told by the time the interviews were conducted .
the other option of administering the questionnaire after the informed consent process but before the surgery could quite possibly have the undesirable effect of interference with the process of care .
nevertheless , it may be possible to recommend that the practice of obtaining separate written consent for anesthesia may be useful in selected settings .
we suggest that the consent form used should :
be simply written without legal jargon.contain cues to the anesthetist regarding the issues to be covered.not lengthy and in itself provide the information but should keep the onus on the anesthetist to do so ( thereby allowing the information to be tailored to the individual patient 's needs and educational level , while at the same time reducing the risk that the form be substituted for the informed consent process ) , andcontain ample space to document the information discussed .
not lengthy and in itself provide the information but should keep the onus on the anesthetist to do so ( thereby allowing the information to be tailored to the individual patient 's needs and educational level , while at the same time reducing the risk that the form be substituted for the informed consent process ) , and contain ample space to document the information discussed .
this study shows that in a caribbean setting , the introduction of separate written consent for anesthesia improved the overall adequacy of the informed consent process .
patients who were asked to sign a separate anesthesia - specific consent form were better informed about the nature and purpose of anesthesia , common side effects , and rare but serious complications . | background and aims : this study aimed to determine whether a separate written consent form improved the efficacy of the informed consent process for anesthesia in adult patients undergoing elective surgery at a tertiary care teaching hospital.material and methods : we randomized patients into two groups prospectively .
the first group ( group a ) signed the hospital 's standard consent for operation form only while the second group ( group b ) signed a separate consent for anesthesia form additionally .
patients were interviewed postoperatively with an eight - item questionnaire with responses in a 5-point likert scale .
a composite adequacy of consent index was generated from the responses and analyzed.results:two hundred patients ( 100 in each group ) were studied .
all patients indicated that the anesthesiologist(s ) had their permission to proceed with their anesthesia care .
the mean adequacy of consent index score in group b was higher than that of group a ( 30.6 4.6 [ standard deviation ( sd ) ] vs. 27.9 5.2 [ sd ] ) ( p < 0.001 ) .
the separate written consent had a positive impact on the patients understanding of the nature and purpose of the intended anesthesia procedures ( p = 0.04 ) , satisfaction with the adequacy of information provided about common side effects ( p < 0.001 ) and rare but serious complications ( p = 0.008).conclusions : a separate written consent for anesthesia improved the efficacy of the informed consent process with respect to better information about the nature and purpose of anesthesia , common side effects , and rare but serious complications . |
small - cell esophageal cancer ( scec ) is a rare tumor accounting for approximately 1% of all esophageal malignancies .
scec behaves aggressively with early systemic metastasis , so prognosis is poor . although combined treatment including surgery , chemotherapy , and radiotherapy has been attempted , no optimum treatment approach for scec has been established .
recently , it has been regarded as a systemic disease , and systemic chemotherapy has become the treatment of choice .
because of their histopathological similarity , the chemotherapy used for small - cell lung cancer ( sclc ) is often chosen for scec .
because pharmacokinetics in patients undergoing hemodialysis differ from those in patients with normal renal function , in hemodialysis patients it is difficult to determine a safe and effective dose and dosing schedule for anticancer agents , including the optimum timing of hemodialysis .
therefore an appropriate regimen of chemotherapy for patients undergoing hemodialysis has not been clearly established .
there are no reports in the literature of chemotherapy for patients with scec maintained on hemodialysis .
we herein report a case with scec on hemodialysis to whom cisplatin ( cddp ) combined with etoposide ( vp-16 ) was administered safely and effectively .
because of chronic glomerulonephritis a 54-year - old male had been maintained on hemodialysis for approximately 10 years at his local hospital .
he presented with difficulty in swallowing and was examined by endoscopy in november 2007 , which led to diagnosis of esophageal cancer .
he was admitted to our hospital in december , and esophagography showed an elevated mass with ulceration , measuring 7 cm in diameter , in the cervical esophagus ( fig .
esophageal endoscopy revealed an irregularly elevated lesion occupying approximately two - thirds of the circumference , with ulceration , 1823 cm from his incisors ( fig .
computed tomography ( ct ) revealed a solid mass , measuring 28 mm in a diameter , in the cervical esophagus , which invaded the trachea , and lymph node enlargement in the cervical paraesophageal area , the supraclavicular area , the tracheobronchial area , and the area along the lesser curvature ( fig .
blood chemistry analysis revealed an elevated serum level ( 107.9 pg / ml ) of pro - gastrin - releasing peptide ( pro - grp).fig .
1a esophagography revealed an elevated mass with ulceration , measuring 7 cm in diameter , in the cervical esophagus .
b esophageal endoscopy revealed an irregularly elevated lesion occupying approximately two - thirds of the circumference , with ulceration , 1823 cm from his incisors .
c histopathologic examination of the biopsy specimens revealed that the tumor was composed of small , round - to - oval cells with hyperchromatic nuclei and scant cytoplasm ( h&e stain 100 ) .
d computed tomography ( ct ) revealed a solid mass , measuring 28 mm in a diameter , in the cervical esophagus , which invaded the trachea a esophagography revealed an elevated mass with ulceration , measuring 7 cm in diameter , in the cervical esophagus .
b esophageal endoscopy revealed an irregularly elevated lesion occupying approximately two - thirds of the circumference , with ulceration , 1823 cm from his incisors .
c histopathologic examination of the biopsy specimens revealed that the tumor was composed of small , round - to - oval cells with hyperchromatic nuclei and scant cytoplasm ( h&e stain 100 ) . d computed tomography ( ct ) revealed a solid mass , measuring 28 mm in a diameter , in the cervical esophagus , which invaded the trachea the lesion was diagnosed as t4 , n1 , m1 , and stage iv ( uicc tnm classification ) . because the tumor was judged to be unresectable , chemotherapy was selected as the treatment for this case .
we knew cddp and vp-16 were effective in the treatment of sclc , leading us to a decision to use these anticancer agents for the systemic chemotherapy .
the chemotherapeutic regimen consisted of cddp on day 1 and vp-16 on days 1 , 3 and 5 , every 4 weeks . in the conventional schedule of cddp and vp-16 therapy for sclc , vp-16 is administered on days 13 . however , we wanted to match the day of administration with the day of dialysis without reducing the total dosage of vp-16 . therefore , we chose a different schedule of vp-16 , and administered it on days 1 , 3 , and 5 . the administration schedule for the two agents on day 1 consisted of intravenous injection of vp-16 in 500 ml normal saline for 120 min and of cddp for 60 min after the end of vp-16 infusion , and no hydration was performed .
for this patient , standard - dose chemotherapy was administered , consisting of cddp and vp-16 at 80 and 100 mg / m , respectively .
he was hemodialyzed with a cellulose triacetate dialyzer three times per week , for approximately 4 h per hemodialysis session . on the days of chemotherapy ,
hemodialysis was started as soon as possible ( within 30 min ) after completion of administration of the chemotherapeutic agents ( fig .
2the chemotherapeutic regimen consisted of cddp on day 1 and vp-16 on days 1 , 3 , and 5 , every 4 weeks . the schedule of administration of the two agents on day 1 consisted of intravenous injection of vp-16 for 120 min then cddp for 60 min after the end of vp-16 infusion .
this patient was hemodialyzed three times per week , for approximately 4 h per hemodialysis session . on the days of chemotherapy ,
hemodialysis was started as soon as possible ( within 30 min ) after completion of administration of the agents the chemotherapeutic regimen consisted of cddp on day 1 and vp-16 on days 1 , 3 , and 5 , every 4 weeks .
the schedule of administration of the two agents on day 1 consisted of intravenous injection of vp-16 for 120 min then cddp for 60 min after the end of vp-16 infusion .
this patient was hemodialyzed three times per week , for approximately 4 h per hemodialysis session . on the days of chemotherapy ,
hemodialysis was started as soon as possible ( within 30 min ) after completion of administration of the agents after the fourth course was finished , the lesion was evaluated . a partial response
was noted , and the patient was able to eat solid food after the treatment .
esophagography showed that the tumor was reduced to 4 cm and had become flatter ( fig .
only a mildly irregular mucosa and a minute elevated mass remained in the cervical esophagus , 2224 cm from his incisors ( fig .
a ct scan showed a solid mass which had decreased to 21 mm in size , in the cervical esophagus , which did not seem to invade the trachea .
the serum level of pro - grp fell after the course of chemotherapy and rose after the interval between chemotherapy .
the minimum value of pro - grp was 38.5 pg / ml , but after 4 courses of this regimen , the serum level of pro - grp was 165.7 pg / ml .
an additional 5 courses of treatment were administered . at that time , examinations had shown no progressive growth of the tumor .
the ct scans showed regrowth of the main tumor and multiple cervical lymph node metastases .
because the patient s pain had worsened because of enlargement of the lymph node metastases , and his performance status had abruptly worsened , palliative radiation ( 30 gy ) was administered for the purpose of pain relief . however , because the patient could not eat and was markedly emaciated , we judged that the continuation of the treatment would be difficult , so best supportive care was provided .
one month after stopping treatment , his body weight continued to decrease , and marked general edema occurred .
3a esophagography showed the tumor was reduced to 4 cm and had become flatter .
b esophageal endoscopy revealed that the tumor that projected into the lumen had almost disappeared .
only a mildly irregular mucosa and a minute elevated mass remained in the cervical esophagus , 2224 cm from his incisors .
c a ct scan showed a solid mass which had decreased to 21 mm in size , in the cervical esophagus , which did not seem to invade the trachea .
the size of lymph node swelling had also decreased a esophagography showed the tumor was reduced to 4 cm and had become flatter .
b esophageal endoscopy revealed that the tumor that projected into the lumen had almost disappeared . only a mildly irregular mucosa and a minute elevated mass remained in the cervical esophagus , 2224 cm from his incisors .
c a ct scan showed a solid mass which had decreased to 21 mm in size , in the cervical esophagus , which did not seem to invade the trachea .
the size of lymph node swelling had also decreased with regard to the toxicity of this chemotherapy regimen , the patient complained of only mild nausea and loss of appetite ( grade 1 by nci - ctcae v4.0 ) .
although occasional afebrile neutrocytopenia ( grade 3 ) was apparent from the blood chemistry data , we were easily able to treat it with granulocyte colony stimulating factor ( g - csf ) .
the patient had nephrogenic anemia ( hemoglobin 7.2 g / dl , packed cell volume 23.0% ) just before chemotherapy , and so experienced exacerbation of his anemia ( grade 4 ) as a result of the chemotherapy .
. we measured plasma levels of total cddp ( t - cddp ) and vp-16 .
venous blood samples were collected into tubes just before and after drug administration , then 0.5 , 1 , 2 , 3 , 4 , 5 , 12 h , 1 ( 24 h ) , 2 , 3 , 4 days , and 1 , 2 , 3 weeks after administration . after separating plasma from each sample , the concentrations of t - cddp and vp-16 were measured in a portion of the plasma . as shown in figs . 4 and 5
, we compared the time concentration curves of t - cddp and vp-16 between the patient with renal insufficiency and those with normal renal function . figures 4b and 5b were provided by dr masumi sawada and dr akira wakui , respectively .
the pharmacokinetic parameters , including half - life ( t1/2 ) and area under the curve ( auc ) , were calculated for cddp and vp-16.fig .
4the t - cddp concentration decreased abruptly immediately after administration of cddp ( phase ) and then decreased slowly ( phase ) .
this biphasic pattern of the pharmacokinetics was similar to that for patients with normal renal function . a the hemodialysis patient .
b patients with normal renal function ( the figure was provided by dr masumi sawada , osaka university ) .
5the vp-16 concentration decreased rapidly during the first 4 h after administration ( phase ) and then decreased gradually ( phase ) .
the biphasic pattern of the pharmacokinetics was comparable with that for patients with normal renal function .
b patients with normal renal function ( the figure was provided by dr akira wakui , tohoku university ) . c pharmacokinetics parameters for vp-16 the t - cddp concentration decreased abruptly immediately after administration of cddp ( phase ) and then decreased slowly ( phase ) .
this biphasic pattern of the pharmacokinetics was similar to that for patients with normal renal function . a the hemodialysis patient .
b patients with normal renal function ( the figure was provided by dr masumi sawada , osaka university ) . c pharmacokinetic parameters for cddp the vp-16 concentration decreased rapidly during the first 4 h after administration ( phase ) and then decreased gradually ( phase ) .
the biphasic pattern of the pharmacokinetics was comparable with that for patients with normal renal function . a the hemodialysis patient .
b patients with normal renal function ( the figure was provided by dr akira wakui , tohoku university ) . c pharmacokinetics parameters for vp-16 the t - cddp concentration decreased abruptly immediately after administration of cddp ( phase ) ; afterward it decreased more slowly ( phase ) ( fig .
this biphasic pattern of the pharmacokinetics was similar to that for patients with normal renal function ( in a phase 1 clinical trial ) ( fig .
the t - cddp concentration on initiation of hemodialysis was 2.31 g / ml . the maximum drug concentration ( cmax ) ( cddp 50 mg / body ) as shown in fig .
4b was higher than that observed in our data ( cddp 120 mg / body ) .
however , in other studies , it was reported that the cmax was 1.40 , 0.98 , 1.07 g / ml ( cddp 80 mg / body ) , 3.31 g / ml ( cddp 80 mg / m ) , and 2.90 g / ml ( cddp 100 mg / m ) .
the reason why the value of cmax in a phase 1 clinical trial tends to be high is unclear . however , our data were consistent with those in previous reports .
it decreased to 1.39 g / ml at 0.5 h , and was 1.56 g / ml 4 h after the initiation .
the lower limit of detection of t - cddp was 0.1 g / ml . the maximum t - cddp concentration was 2.31 g / ml , and it had decreased to 0.17 g / ml 28 days after the administration of cddp .
cddp remained in the plasma for at least 28 days , but the last concentration approached the lower limit of detection .
we also measured the plasma levels of t - cddp in the first and second courses and compared each point in both courses .
the t - cddp concentrations in the second course were significantly higher than those in the first course ( wilcoxon t test , p < 0.01 ) , indicating a cumulative effect of cddp in this regimen .
the t1/2 was 0.036 h , and t1/2 was 119 h for the first course of cddp .
in contrast , the t1/2 was 0.411 h and t1/2 was 164 h for the second course .
the auc was 265 and 363 g h / ml in the first and second courses , respectively .
the t1/2 was extended and the auc was increased in the second course in comparison with the first course .
many reports have described that the t1/2 was approximately 100 h in patients with normal renal function , and tokunaga et al .
reported that the t1/2 for cddp was 0.53 0.07 h , t1/2 was 94.2 11.6 h , and auc was 71.3 6.26 g h / ml after administration of 90.8 6.34 mg to patients with normal renal function . in this case
, we obtained a similar t1/2 value , but the auc tended to be greater than for patients with normal renal function .
the vp-16 maximum concentrations were 9.96 , 10.44 , and 10.45 g / ml after the three administrations and rapidly decreased to 5.06 , 6.07 , and 5.76 g / ml 4 h after administration ( phase ) .
the pharmacokinetics had a biphasic pattern which was also comparable with the curves for patients with normal renal function ( in a phase 1 clinical trial ) ( fig .
the concentration had decreased to 1.45 g / ml at 24 h and 0.62 g / ml at 48 h after administration , which was approaching the lower limit of detection .
almost all of the vp-16 in the plasma was excreted within 48 h. comparison of each point after the first and second administrations revealed the vp-16 concentrations were not significantly different ( wilcoxon t test , p = 0.068 ) , and no significant cumulative effect caused by the alternate - day administration for 3 days was apparent .
the t1/2 was 2.31 h and t1/2 was 17.2 h after the first administration in the first course of treatment , and the t1/2 was 3.10 h and t1/2 was 16.9 h after the second administration during the first course .
the auc values were 128 and 139 g h / ml , respectively , after the first and second administrations during the first course .
on the other hand , wakui et al . reported that the t1/2 was 0.13 and 0.30 h , t1/2 was 4.85 and 4.01 h , and the auc was 95.7 and 94.8 g h / ml , respectively , after the administration of 120 mg / m in patients with normal renal function ( based on a phase 1 clinical trial ) .
this suggested that there was a tendency for both the t1/2 and auc to increase in this dialysis patient in comparison with patients with normal renal function .
was noted , and the patient was able to eat solid food after the treatment .
esophagography showed that the tumor was reduced to 4 cm and had become flatter ( fig .
only a mildly irregular mucosa and a minute elevated mass remained in the cervical esophagus , 2224 cm from his incisors ( fig .
a ct scan showed a solid mass which had decreased to 21 mm in size , in the cervical esophagus , which did not seem to invade the trachea .
the serum level of pro - grp fell after the course of chemotherapy and rose after the interval between chemotherapy .
the minimum value of pro - grp was 38.5 pg / ml , but after 4 courses of this regimen , the serum level of pro - grp was 165.7 pg / ml .
an additional 5 courses of treatment were administered . at that time , examinations had shown no progressive growth of the tumor . however , 12 months after the initial treatment disease progression was observed .
the ct scans showed regrowth of the main tumor and multiple cervical lymph node metastases . because the patient s pain had worsened because of enlargement of the lymph node metastases , and his performance status had abruptly worsened , palliative radiation ( 30 gy ) was administered for the purpose of pain relief .
however , because the patient could not eat and was markedly emaciated , we judged that the continuation of the treatment would be difficult , so best supportive care was provided .
one month after stopping treatment , his body weight continued to decrease , and marked general edema occurred .
3a esophagography showed the tumor was reduced to 4 cm and had become flatter .
b esophageal endoscopy revealed that the tumor that projected into the lumen had almost disappeared . only a mildly irregular mucosa and a minute elevated mass remained in the cervical esophagus , 2224 cm from his incisors .
c a ct scan showed a solid mass which had decreased to 21 mm in size , in the cervical esophagus , which did not seem to invade the trachea .
the size of lymph node swelling had also decreased a esophagography showed the tumor was reduced to 4 cm and had become flatter .
b esophageal endoscopy revealed that the tumor that projected into the lumen had almost disappeared . only a mildly irregular mucosa and
a minute elevated mass remained in the cervical esophagus , 2224 cm from his incisors .
c a ct scan showed a solid mass which had decreased to 21 mm in size , in the cervical esophagus , which did not seem to invade the trachea .
with regard to the toxicity of this chemotherapy regimen , the patient complained of only mild nausea and loss of appetite ( grade 1 by nci - ctcae v4.0 ) .
although occasional afebrile neutrocytopenia ( grade 3 ) was apparent from the blood chemistry data , we were easily able to treat it with granulocyte colony stimulating factor ( g - csf ) .
the patient had nephrogenic anemia ( hemoglobin 7.2 g / dl , packed cell volume 23.0% ) just before chemotherapy , and so experienced exacerbation of his anemia ( grade 4 ) as a result of the chemotherapy .
venous blood samples were collected into tubes just before and after drug administration , then 0.5 , 1 , 2 , 3 , 4 , 5 , 12 h , 1 ( 24 h ) , 2 , 3 , 4 days , and 1 , 2 , 3 weeks after administration . after separating plasma from each sample , the concentrations of t - cddp and vp-16
were measured in a portion of the plasma . as shown in figs . 4 and 5 , we compared the time concentration curves of t - cddp and vp-16 between the patient with renal insufficiency and those with normal renal function . figures 4b and 5b
the pharmacokinetic parameters , including half - life ( t1/2 ) and area under the curve ( auc ) , were calculated for cddp and vp-16.fig .
4the t - cddp concentration decreased abruptly immediately after administration of cddp ( phase ) and then decreased slowly ( phase ) .
this biphasic pattern of the pharmacokinetics was similar to that for patients with normal renal function . a the hemodialysis patient .
b patients with normal renal function ( the figure was provided by dr masumi sawada , osaka university ) .
5the vp-16 concentration decreased rapidly during the first 4 h after administration ( phase ) and then decreased gradually ( phase ) .
the biphasic pattern of the pharmacokinetics was comparable with that for patients with normal renal function . a the hemodialysis patient .
b patients with normal renal function ( the figure was provided by dr akira wakui , tohoku university ) .
c pharmacokinetics parameters for vp-16 the t - cddp concentration decreased abruptly immediately after administration of cddp ( phase ) and then decreased slowly ( phase ) .
this biphasic pattern of the pharmacokinetics was similar to that for patients with normal renal function . a the hemodialysis patient .
b patients with normal renal function ( the figure was provided by dr masumi sawada , osaka university ) . c pharmacokinetic parameters for cddp the vp-16 concentration decreased rapidly during the first 4 h after administration ( phase ) and then decreased gradually ( phase ) .
the biphasic pattern of the pharmacokinetics was comparable with that for patients with normal renal function . a the hemodialysis patient .
b patients with normal renal function ( the figure was provided by dr akira wakui , tohoku university ) . c pharmacokinetics parameters for vp-16 the t - cddp concentration decreased abruptly immediately after administration of cddp ( phase ) ; afterward it decreased more slowly ( phase ) ( fig .
this biphasic pattern of the pharmacokinetics was similar to that for patients with normal renal function ( in a phase 1 clinical trial ) ( fig .
the t - cddp concentration on initiation of hemodialysis was 2.31 g / ml . the maximum drug concentration ( cmax ) ( cddp 50 mg / body ) as shown in fig .
4b was higher than that observed in our data ( cddp 120 mg / body ) .
however , in other studies , it was reported that the cmax was 1.40 , 0.98 , 1.07 g / ml ( cddp 80 mg / body ) , 3.31 g / ml ( cddp 80 mg / m ) , and 2.90 g / ml ( cddp 100 mg / m ) . the reason why the value of cmax in a phase 1 clinical trial tends to be high is unclear . however , our data were consistent with those in previous reports .
it decreased to 1.39 g / ml at 0.5 h , and was 1.56 g / ml 4 h after the initiation .
the lower limit of detection of t - cddp was 0.1 g / ml . the maximum t - cddp concentration was 2.31 g / ml , and it had decreased to 0.17 g / ml 28 days after the administration of cddp .
cddp remained in the plasma for at least 28 days , but the last concentration approached the lower limit of detection .
we also measured the plasma levels of t - cddp in the first and second courses and compared each point in both courses .
the t - cddp concentrations in the second course were significantly higher than those in the first course ( wilcoxon t test , p < 0.01 ) , indicating a cumulative effect of cddp in this regimen .
the t1/2 was 0.036 h , and t1/2 was 119 h for the first course of cddp .
in contrast , the t1/2 was 0.411 h and t1/2 was 164 h for the second course .
the auc was 265 and 363 g h / ml in the first and second courses , respectively .
the t1/2 was extended and the auc was increased in the second course in comparison with the first course .
many reports have described that the t1/2 was approximately 100 h in patients with normal renal function , and tokunaga et al .
reported that the t1/2 for cddp was 0.53 0.07 h , t1/2 was 94.2 11.6 h , and auc was 71.3 6.26 g h / ml after administration of 90.8 6.34 mg to patients with normal renal function . in this case , we obtained a similar t1/2 value , but the auc tended to be greater than for patients with normal renal function .
the vp-16 maximum concentrations were 9.96 , 10.44 , and 10.45 g / ml after the three administrations and rapidly decreased to 5.06 , 6.07 , and 5.76 g / ml 4 h after administration ( phase ) .
the pharmacokinetics had a biphasic pattern which was also comparable with the curves for patients with normal renal function ( in a phase 1 clinical trial ) ( fig .
the concentration had decreased to 1.45 g / ml at 24 h and 0.62 g / ml at 48 h after administration , which was approaching the lower limit of detection .
almost all of the vp-16 in the plasma was excreted within 48 h. comparison of each point after the first and second administrations revealed the vp-16 concentrations were not significantly different ( wilcoxon t test , p = 0.068 ) , and no significant cumulative effect caused by the alternate - day administration for 3 days was apparent .
the t1/2 was 2.31 h and t1/2 was 17.2 h after the first administration in the first course of treatment , and the t1/2 was 3.10 h and t1/2 was 16.9 h after the second administration during the first course .
the auc values were 128 and 139 g h / ml , respectively , after the first and second administrations during the first course .
on the other hand , wakui et al . reported that the t1/2 was 0.13 and 0.30 h , t1/2 was 4.85 and 4.01 h , and the auc was 95.7 and 94.8 g h / ml , respectively , after the administration of 120 mg / m in patients with normal renal function ( based on a phase 1 clinical trial ) .
this suggested that there was a tendency for both the t1/2 and auc to increase in this dialysis patient in comparison with patients with normal renal function .
there is no established treatment for the disease , but combination chemotherapy consisting of cddp and vp-16 , such as is given for sclc , is generally administered .
it is well known that patients with chronic renal failure suffer from malignancies at high frequency , as reported by matas et al . .
with the increase in the number of dialysis patients , cases in which malignancies are detected during a dialysis period have increased . when an anticancer agent is administered to a patient with chronic renal failure ,
it is necessary to consider the metabolic pathway of the anticancer agent and to adjust the administration method in order to reduce side effects while maintaining antitumor efficacy .
its half - life ( t1/2 ) is approximately 100 h , which is longer than that of other anticancer agents , so we were concerned about accumulation of the drug in the patient with chronic renal failure .
some papers have indicated that the dose should be reduced to 50% in patients with renal insufficiency [ 9 , 10 ] .
the dose that should be given to patients with chronic renal failure is controversial , and some papers have reported a need to reduce the dose [ 9 , 10 ] .
there have been of reports on cddp and vp-16 chemotherapy for a dialysis patients with scec . in this case , we first discussed the safety of this regimen .
the patient complained of mild nausea and appetite loss , but his dietary intake was reduced by half for approximately 3 days only after administration of cddp .
the nadir was shown to be 1623 days after administration , and did not last longer than in patients with normal renal function .
scec is classified as limited disease ( ld ) or extensive disease ( ed ) according to the veterans administration lung group staging system .
it has been reported that the median survival time ( mst ) for ed is 7.0 months , and that 1-year survival is 29.3% . in our case
the patient was staged as ed , and he maintained stable disease ( sd ) for 12 months , and survived for 13 months . in comparison with the previous report , the curative effect in this case was slightly better .
we also studied the good results in terms of safety and efficacy and their relationship to the pharmacokinetics .
the timing of hemodialysis initiation after administration of the anticancer agent and the doses of the anticancer agents were very important in terms of the safety and efficacy of the treatment . in terms of safety , it is necessary to prevent serious side effects associated with cddp accumulation .
the free - cddp ( f - cddp ) could be removed easily by hemodialysis . however
, protein binding of cddp in the plasma is approximately 90% , and f - cddp binds to plasma proteins immediately and strongly .
protein - bound cddp is difficult to remove effectively . in this case , the f - cddp was removed quickly by hemodialysis immediately after its administration , thus blocking some of the binding to the plasma proteins . as a result ,
the t - cddp concentration time curve and the value of t1/2 in this case were almost equal to those for patients with normal renal function reported previously . on the basis of a literature review ,
however , there are individual differences in clinical side effects . in this case , there were no severe side effects .
however , it should be kept in mind that there is a risk of severe side effects , especially for patients with compromised renal function .
the dosing interval in this regimen was 4 weeks , but the cumulative effect of cddp was clear upon comparison of the pharmacokinetics in the first and second courses . in this case , there was no clinically significant increase in the side effects during the second course , but it is necessary to take care when administering this regimen on this schedule .
it has been reported that the efficacy of platinum - containing drugs depends on both the length of exposure and the concentration , and the anti - tumor effect was likely to correlate with the auc , because it contains both elements .
when cddp is administered to a dialysis patient , the auc depends not only on the dose of drug administered but also on the timing of dialysis initiation . in this case , the aucs were increased compared with patients with normal renal function .
this may be one of the reasons we obtained a slightly better anti - tumor effect .
we also analyzed the pharmacokinetics of vp-16 , which is excreted mainly through the bile and stool , only slightly in the urine , unlike cddp . because a small percentage of the administered vp-16 is excreted into the urine
, the dose of the anticancer agent and the dialysis schedule may not affect the pharmacokinetics significantly . however , some papers recommended dose reduction of vp-16 for dialysis patients , because of its poor dialyzability . in this case , the maximum concentration was almost equal to that in patients with normal renal function , but the t1/2 was longer .
however , a large quantity was excreted in < 48 h , and it was revealed that there was no cumulative effect by comparison of the pharmacokinetics after each administration . in terms of safety , the usual dose could be safely administered by starting hemodialysis soon after administration of the drug . in terms of efficacy ,
the auc was larger than that for patients with a normal renal function , and thus there is a possibility that we obtained a slightly better anti - tumor effect compared to patients with normal renal function .
chemotherapy using this regimen was performed safely without severe side effects , and almost equal anti - tumor efficacy was observed compared with patients with normal renal function .
on the basis of the above - mentioned pharmacokinetics , it was suggested that the good results were because of the time concentration relationship , which resembled that for patients with normal renal function . in terms of safety and efficacy , this regimen , which consisted of the usual dose of chemotherapeutic agents , and the initiation of dialysis immediately after administration of the agents , was considered to be reasonable . in conclusion , this full - dose combination chemotherapy regimen comprising cddp and vp-16 seems to be safe and effective against esophageal scec in patients undergoing regular hemodialysis .
further study is needed for selection of suitable chemotherapeutic regimens , the optimum dose of each drug , and the timing of hemodialysis . | a 54-year - old male undergoing hemodialysis was admitted to our hospital because of difficulty in swallowing .
esophagography and esophageal endoscopy revealed an irregular ulcerated lesion in the cervical esophagus .
it was diagnosed as a small - cell esophageal cancer from the biopsy sample .
computed tomography showed a tumor infiltrating the trachea and a few lymph node metastases in the cervix , upper mediastinum , and abdomen .
the patient was started on chemotherapy with cisplatin ( cddp ) and etoposide ( vp-16 ) , which had been reported to be effective for small - cell lung cancer .
the patient was treated with cddp ( 80 mg / m2 ) on day 1 and vp-16 ( 100 mg / m2 ) on days 1 , 3 , and 5 , every 4 weeks . on the days of chemotherapy ,
hemodialysis was started as soon as possible after completion of administration of the agents .
no severe side effects were observed .
after 4 courses of therapy , the patient achieved a partial response . |
reducing the gap between research evidence and clinical practice , or the so - called
evidence - practice gap , can lead to improved patient outcomes1 and reductions in healthcare costs2 .
one example of the
evidence - practice gap in stroke rehabilitation is the research finding that electrical
stimulation therapy ( es ) is effective in the treatment of upper and lower limb
paralysis3 .
this gap is very common despite es implementation having been
recommended by many clinical studies5 , 6 and evidence - based clinical practice
guidelines in several countries7,8,9 .
one proposed reason for the evidence - practice gap is the lack of a collaborative and
symbiotic relationship between practitioners and researchers3 .
however , we do not know how often practitioners and researchers
collaborate in clinical studies of es for stroke .
if collaboration patterns are understood
and improved , the evidence - practice gap may be reduced .
thus , the aim of this study was to
investigate the degree of collaboration between practitioners and researchers through
research papers related to the implementation of es for stroke patients .
a systematic review of the literature published before january 7 , 2015 was conducted to
collect data from es studies . the literature recorded in five databases ( pubmed , cochrane
database , pedro , otseeker , and ichushi web )
was explored for search terms related to stroke
and es . because of limited manpower and the difficulty in identifying papers that matched
the purpose of our study , manuscripts were only included if the search terms appeared in the
study title .
the following search terms were used in this study : stroke*[ti ] or apoplexy[ti ]
or cerebrovascular[ti ] or vascular[ti ] or accident*[ti ] or attack[ti ] and electrical[ti ] and
stimulation*[ti ] .
inclusion criteria were original papers that reported on es for the upper
or lower limbs following stroke , after the exclusion of case reports , opinions , systematic
reviews , protocols , letters , brain stimulation studies , and papers written in languages
other than english or japanese .
two reviewers independently extracted data based on the criteria , and assessed the
collaboration patterns between practitioners and researchers based on the following
conditions .
a practitioner was defined as a person who included a hospital as an
affiliation , while a researcher was identified as an individual who only belonged to a
research institution such as a university , college , or research center . in this study ,
a
researcher was defined as a person whose affiliation in the author s list was for a
university but who actually worked in a hospital at the university , because a decision
can not be made based on affiliation alone .
the primary outcome was the prevalence of research papers that included a practitioner as
an author .
secondary outcomes were the prevalence of research papers that included a
practitioner as an author or in the acknowledgements , and research papers in which the
practitioner was the first author . in the statistical analysis ,
the degree of collaboration was calculated for every year from
2009 to 2014 , and a time series analysis was performed on the data .
the time series analysis
was done with jmp pro11 ( sas institute inc . ,
cary , north carolina ) , and white noise was
employed to determine the presence of a significant autocorrelation .
our literature review identified 489 papers , and our final analysis included 165 papers
based on the selection criteria .
the prevalence of papers in which a practitioner was
included as an author was 38.8% ( n = 64 ) , while the prevalence of papers in which a
practitioner was included as an author or in the acknowledgements section was 49.7% ( n = 82 ,
table
1table 1.the prevalence of papers which a practitioner contributed topractitioner included as an authorpractitioner included as an author or in the
acknowledgementspractitioner listed as the first authorprevalence0.39 0.50 0.34 ) .
a practitioner was listed as the first author in 33.9% ( n =
56 ) of the papers .
these results indicate that the degree of collaboration between practitioners
and researchers was less than 50% .
data for each year indicated that the prevalence of papers in which a practitioner was
included as an author , as an author or in the acknowledgements , and as the first author
remained unchanged ( table 2table 2.the collaboration patterns over the past 6 yearsprevalenceyear200920102011201220132014a0.37 0.50 0.47 0.20 0.55 0.34 b0.37 0.50 0.47 0.30 0.59 0.62 c0.42 0.21 0.21 0.50 0.32 0.41 a : the prevalence of papers in which a practitioner was included as an author .
b : the
prevalence of papers in which a practitioner was included as an author or in the
acknowledgements section .
c : the prevalence of papers in which a practitioner was
listed as the first author ) .
the time series analysis revealed that there was no significant
autocorrelation ( p = 0.620.99 ) .
therefore , the results indicate that there was no white
noise obscuring collaboration patterns between practitioners and researchers , and that they
have remained unchanged since 2009 .
a : the prevalence of papers in which a practitioner was included as an author .
b : the
prevalence of papers in which a practitioner was included as an author or in the
acknowledgements section .
c : the prevalence of papers in which a practitioner was
listed as the first author
in this study , a limited degree of collaboration between practitioners and researchers was
found in published studies employing es for stroke patients despite the fact that study
participants are generally recruited in hospitals . in the following discussion ,
two reasons
are suggested for the limited cooperation between practitioners and researchers , and we
argue the importance of collaboration .
moreover , researchers who
have employed es for stroke have reported clinically significant findings and are thus
motivated to adopt es . however , once these researchers leave the clinical field , their
communication with practitioners is often limited .
second , most practitioners do not spend
their free time participating in research activities .
for example , our preliminary study
found that , if given the opportunity , less than 50% of physical therapists would spend their
free time participating in research activities .
previous reports in other research fields have indicated that successful relationships
between practitioners and researchers often lead to evidence - based practices and good
patient treatment10,11,12 .
thus , these issues were
resolved , practitioners would more likely implement and facilitate evidence - based
practices . in conclusion
, more collaboration between practitioners and researchers may facilitate the
implementation of es , which would help close the gap between research evidence and clinical
practice .
furthermore , this collaboration would likely result in higher levels of recovery
among patients with stroke . | [ purpose ] the purpose of this study was to investigate the degree of collaboration
between practitioners and researchers through research papers related to the
implementation of electrical stimulation ( es ) for stroke patients .
[ methods ] a systematic
review of the literature was conducted to collect data from es studies published before
january 7 , 2015 .
five databases were searched for search terms related to stroke and es .
inclusion criteria were original papers that reported on es of the upper or lower limbs
following stroke , after the exclusion of case reports , brain stimulation studies , and
papers written in any languages other than english or japanese .
the outcome was the
prevalence of research papers that included a practitioner as an author , that included a
practitioner as an author or in the acknowledgements , and in which the practitioner was
the first author .
[ results ] based on the selection criteria , 165 papers were included in
the final analysis .
the prevalence of papers in which a practitioner was included as an
author was 39% .
the prevalence of papers in which a practitioner was included as an author
or in the acknowledgements was 50% .
a practitioner was the first author of 34% of the
papers .
[ conclusion ] collaboration on research papers related to es for stroke patients is
limited . |
this prospective cohort study involved 64 consecutive patients with unstable intertrochanteric fractures treated with calcar preserving uncemented collared bipolar hemiarthroplasty between may 2011 and december 2012 in private ortopedia hospital .
this study was carried out in accordance with the ethical standards laid down in the 1964 declaration of helsinki and its later amendments .
institutional review board approved the study protocol and all patients and/or primary caregivers gave informed consent prior to their inclusion in the study .
all consecutive elderly patients aged 75 years and over with osteoporotic ( singh index grade 3 ) unstable intertrochanteric fractures ( ao / ota type 31-a2 and 31-a3 ) were included in the study .
patients with immobility before the injury , pathological fractures , polytraumatic patients , patients with simultaneous fractures of the ipsilateral extremity and finally patients , who refused participation were excluded from the study .
three patients died from cardiopulmonary disease , two patients died from renal failure , one patient died in a road traffic accident within a year after surgery and three patients died before the minimum follow - up period with unrelated reasons of the fracture treatment and one patient could not be contacted , thus leaving a total of 54 patients for the final analysis .
etiology of all fractures was low - energy trauma such as simple falls at home .
all operations were performed by a single experienced surgeon with an interval of 0 to 3 days after initial injury in accordance with the concomitant comorbidities .
all patients were operated under spinal anesthesia in lateral decubitus position using a posterior approach .
the femoral neck was cut with an oscillating saw similar to the preparation of femur in total hip arthroplasty and the femoral head was removed leaving the rest of the femoral neck and femoral calcar . based on the assessment of fracture pattern and type ,
if the stability between the implant and femur could be achieved by compaction ( mostly ao / ota type 31-a2 fracture and/or trochanter minor fractured with a little spike ) , an extra fixation of the neck and trochanter minor ( such as trochanteric grip or cable ) was discarded , then the prosthesis was tapped into place following standard reaming ( fig .
if it was thought that stability may not be achieved by the compaction technique of the trochanter minor fracture fragments ( mostly ao / ota type 31-a3 fracture and/or trochanter minor fractured with a large part towards distal ) or if it was decided after compaction that stability had not been achieved , then cable was used .
if there was a concomitant fracture of the trochanter major , then stability was achieved by binding both the trochanter major and minor ( fig .
the femoral stem was inserted in a distal press - fit manner into the femoral canal .
after the stability assessment and insertion of the appropriate femoral head , the hip joint was reduced .
a suction drain was applied and the surgical wound was closed . in all cases ,
all drains were removed , and ambulation with full weight bearing with aid of a walker or crutches was started and encouraged .
patients with no wound complications and those who could take a few steps were discharged subsequently .
follow - up evaluation was performed on third day , 45th day , third month , sixth month , and every six month postoperatively .
anteroposterior and lateral plain hip radiographs were taken after surgery and at each follow - up .
radiographs were examined for evidence of nonunion , component position ( alignment ) , loosening and subsidence .
union was defined as bony bridging across the fracture line on at least three cortices .
more than 3 varus and valgus malalignment and more than 5 mm longitudinal subsidence of the femoral stem were considered significant.7 ) clinical evaluations were performed using palmer and parker mobility score and pain was evaluated with visual analogue scale ( vas ) at each follow - up.8 ) the duration of operation ( minutes ) , amount of blood transfusion ( number of units ) , and duration of hospitalization ( days ) were recorded .
repeated measures were used for statistical analyses which were performed using spss ver . 16 .
chicago , il , usa ) . significance level was accepted as p < 0.05 .
all patients were operated under spinal anesthesia in lateral decubitus position using a posterior approach . the femoral neck was cut with an oscillating saw similar to the preparation of femur in total hip arthroplasty and the femoral head was removed leaving the rest of the femoral neck and femoral calcar . based on the assessment of fracture pattern and type , if the stability between the implant and femur could be achieved by compaction ( mostly ao / ota type 31-a2 fracture and/or trochanter minor fractured with a little spike ) , an extra fixation of the neck and trochanter minor ( such as trochanteric grip or cable ) was discarded , then the prosthesis was tapped into place following standard reaming ( fig .
1 ) . if it was thought that stability may not be achieved by the compaction technique of the trochanter minor fracture fragments ( mostly ao / ota type 31-a3 fracture and/or trochanter minor fractured with a large part towards distal ) or if it was decided after compaction that stability had not been achieved , then cable was used .
if there was a concomitant fracture of the trochanter major , then stability was achieved by binding both the trochanter major and minor ( fig .
the femoral stem was inserted in a distal press - fit manner into the femoral canal .
after the stability assessment and insertion of the appropriate femoral head , the hip joint was reduced .
a suction drain was applied and the surgical wound was closed . in all cases , we have used echelon primary hip system ( smith and nephew inc . , memphis , tn , usa ) .
on the first postoperative day all drains were removed , and ambulation with full weight bearing with aid of a walker or crutches was started and encouraged .
patients with no wound complications and those who could take a few steps were discharged subsequently .
follow - up evaluation was performed on third day , 45th day , third month , sixth month , and every six month postoperatively .
anteroposterior and lateral plain hip radiographs were taken after surgery and at each follow - up .
radiographs were examined for evidence of nonunion , component position ( alignment ) , loosening and subsidence .
union was defined as bony bridging across the fracture line on at least three cortices .
more than 3 varus and valgus malalignment and more than 5 mm longitudinal subsidence of the femoral stem were considered significant.7 ) clinical evaluations were performed using palmer and parker mobility score and pain was evaluated with visual analogue scale ( vas ) at each follow - up.8 ) the duration of operation ( minutes ) , amount of blood transfusion ( number of units ) , and duration of hospitalization ( days ) were recorded .
repeated measures were used for statistical analyses which were performed using spss ver . 16 .
the study finally included 15 male and 39 female patients with a mean age of 81.3 years ( range , 75 to 93 years ) .
the mean duration of operation was 86.6 minutes ( range , 60 to 125 minutes ) .
the mean transfused blood units were 1.2 units ( 420 ml ; range , 0 to 3 units ) .
the average duration of hospital stay was 5.3 days ( range , 3 to 7 days ) . and mean follow - period was 31 months ( range , 24 to 52 months ) . bone mineral density ( bmd ) was available for only 32 patients , and mean t score was -3.9 ( range , -2.5 to -4.6 ) .
the mean mobility score obtained from patients and their relatives before fracture was 6.20 ( standard deviation [ sd ] , 1.37 ) . postoperative first day mobilization was attempted for all patients with the aid of a walker or crutches .
although mobilization was mostly achieved 40/54 , some could only stand still , 14/54 therefore patients were re - evaluated on postoperative third day .
the results of the statistical analysis revealed mobility scores to have increased at each follow - up after three days ( greenhouse - geisser : f = 27.236 , df = 2.554 , p = 0.000 ) ( table 1 ) .
when the visual analog scale was evaluated preoperatively and postoperatively , the mean scores were seen to decrease over time .
the mean scores were statistically significant between all follow - up periods except between 12 months and 24 months ( greenhouse - geisser : f = 136.999 , df = 3 , p = 0.000 ) ( table 1 ) .
radiological interpretation revealed bony union in all cases . with regard to the changes in the alignment of the implant , there was no case with more than 3 varus or valgus malalignment .
the degree of subsidence of the femoral stem was 1 , 2 , 3 , and 4 mm in 9 , 6 , 6 , and 2 patients , respectively .
there was no more than 5 mm subsidence or osteolysis in any of the cases .
one patient had deep vein thrombosis ( treated with anticoagulation ) , one patient had early postoperative delirium , two patients had superficial wound complications with drainage and delayed healing ( treated with antibiotherapy ) .
cable penetrated the trochanter major at third month of operation where the cable was used to stabilize the trochanteric fracture .
there was no need for an additional operation for this patient because she was able to walk without any pain or symptom .
the mean mobility score obtained from patients and their relatives before fracture was 6.20 ( standard deviation [ sd ] , 1.37 ) .
postoperative first day mobilization was attempted for all patients with the aid of a walker or crutches .
although mobilization was mostly achieved 40/54 , some could only stand still , 14/54 therefore patients were re - evaluated on postoperative third day .
the results of the statistical analysis revealed mobility scores to have increased at each follow - up after three days ( greenhouse - geisser : f = 27.236 , df = 2.554 , p = 0.000 ) ( table 1 ) . when the visual analog scale was evaluated preoperatively and postoperatively ,
the mean scores were statistically significant between all follow - up periods except between 12 months and 24 months ( greenhouse - geisser : f = 136.999 , df = 3 , p = 0.000 ) ( table 1 ) .
radiological interpretation revealed bony union in all cases . with regard to the changes in the alignment of the implant , there was no case with more than 3 varus or valgus malalignment .
the degree of subsidence of the femoral stem was 1 , 2 , 3 , and 4 mm in 9 , 6 , 6 , and 2 patients , respectively .
there was no more than 5 mm subsidence or osteolysis in any of the cases .
one patient had deep vein thrombosis ( treated with anticoagulation ) , one patient had early postoperative delirium , two patients had superficial wound complications with drainage and delayed healing ( treated with antibiotherapy ) .
cable penetrated the trochanter major at third month of operation where the cable was used to stabilize the trochanteric fracture . there was no need for an additional operation for this patient because she was able to walk without any pain or symptom
there is still no consensus on the best treatment method for intertrochanteric fractures and fixation materials . for several decades
, the treatment of choice for unstable intertrochanteric fractures in elderly patients has been open reduction and internal fixation .
sliding hip screws are widely used,91011 ) but it has been reported that treatment with dynamic hip screws has resulted in implant problems at a rate of between 1% and 20% .
problems related to fracture type , bmd , reduction quality , implant shape , and localization of lag screw in the femoral head have been reported.12 ) in addition , osteoporotic elderly patients , in particular , have been reported to have a high prevalence of unsatisfactory functional results , with unacceptable shortening and external rotation deformity of the limb , high cut - out , and varus displacement rates with extramedullary devices.1314 ) the use of intramedullary devices has become more widespread with few researchers claiming that intramedullary devices have shown fewer complications and re - operations.1516 ) the cochrane collaboration performed a systematic review of trochanteric fractures with 43 trials.17 ) twenty - two trials involving 3,746 patients compared the gamma nail with any number of sliding hip screw designs and gamma nail was found to be associated with an increased risk of operative and later fractures of the femur and an increased reoperation rate . there were no major differences between implants in terms of the rates of infection mortality , or medical complications .
five trials involving 623 patients compared the intramedullary hip screw ( imhs ) with sliding hip screw .
fracture fixation complications were more common in the imhs group and results for postoperative complications , mortality and functional outcomes were similar in both groups .
early mobilization is of particular importance for these patients as it might decrease the risk of mortality and morbidity , although older patients are unable to walk soundly enough and are only capable of partial weight - bearing in the postoperative period following internal fixation methods.1819 ) therefore , many researchers have shown interest in arthroplasty in trochanteric fractures .
haentjens et al.20 ) compared the clinical results of internal fixation and bipolar arthroplasty for unstable trochanteric fractures and reported 75% satisfactory results and fewer postoperative complications in the latter group .
they insisted that early weight - bearing was the major factor responsible for decreasing postoperative complications .
elderly patients , who are often unable to cooperate with partial weight - bearing ( due to neurovascular problems , gonarthrosis , spinal stenosis and other walking difficulties ) required after an internal fixation are able to accept full weight - bearing easily .
lu - yao et al.4 ) reported that 27% of hospitalized patients with a hip fracture die within 12 months of occurrence of fracture .
when we consider this concept with respect to time frame , it becomes obvious that additional six months with full weight bearing means one fourth of the rest of an elderly patient 's life .
many surgeons prefer arthroplasty for the treatment of unstable trochanteric fractures in the elderly in order to decrease complications .
choy et al.7 ) used arthroplasty and reported mean 80.6 9.3 harris hip score at the end of two years follow - up period .
andress et al.21 ) showed adequate osteointegration of the implant , supporting the conclusion that an uncemented prosthesis can be used successfully to treat complex , unstable trochanteric fractures .
although the clinical outcomes were similar for patients having internal fixation and hemiarthroplasty , the latter had a lower postoperative complication rate and the patients were capable of earlier weight - bearing.20 ) kayali et al.5 ) reported a significant difference in full weight - bearing time between the two groups .
though more costly , cone hemiarthroplasty is an appropriate treatment option for patients with unstable intertrochanteric fractures , which can achieve earlier mobilization .
there are a few published studies in treatment of unstable intertrochanteric fractures with total hip arthroplasty .
successful treatments were reported especially concurrent to osteodegeneration.222324 ) however , it has been noticed that total hip arthroplasty involves more operation time , a large amount of blood loss , more risky for dislocation , and also much expensive when compared to bipolar hemiarthroplasty .
it is proposed that the use of bipolar arthroplasty instead of total hip replacements can reduce these complications to an acceptable rate.2526 ) our method revealed similar mean transfused blood units ( 1.2 unit [ 420 ml ] vs. 1.3 units,5 ) 350 ml,26 ) 460 ml,22 ) and 1,050 ml25 ) ) and similar surgery time ( 86.6 minutes vs. 90 minutes,5 ) 71 minutes,26 ) 110 minutes,22 ) and 151 minutes25 ) ) as has been reported in literature .
the mean hospital stay for our patients was shorter than ( 5.3 days vs. 13 days,5 ) 10.9 days,26 ) 9.5 days,22 ) and 19 days25 ) ) that reported in literature .
the early postoperative mobility scores of our patients were high and the postoperative 24th month scores were similar to the preoperative scores . when the vass were compared with preoperative scores ,
thus , the 24-months follow - up revealed no loosening of the cables , no subsidence , and no femoral fractures , indicating that the early results from this method may be valuable . retaining of lesser trochanter and reconstruction of femoral calcar are important for improving periprosthetic biomechanics and reducing local complications.27 ) as the placement of the prosthesis is established distally ( distal fitting femoral stem ) , there is no weight - bearing in the calcar region in the early period when full weight - bearing is allowed .
the calcar region carries little weight thus allowing the possibility of a complication - free recovery . in the long - term , union in the calcar region and osteointegration of
moreover , the torque to the iliopsoas muscles which inserts to trochanter minor allows the continuing muscle function to strengthen the muscles around the hip .
the most frequent late complications following fixation of intertrochanteric fractures are malunion , nonunion , pseudoarthrosis , osteonecrosis of the femoral head , joint damage ( associated with fixation slippage or chondrolysis ) , soft tissue irritation from the implant , bursitis , impingement , infection , trochanteric problems , and chondrolysis . in some series , particularly in patients with unstable fractures ,
revision or reoperation rate has been published between 5.5% and 22.5% with internal fixation devices.2528 ) majority of above mentioned problems can be avoided with calcar preservation hemiarthroplasty .
hence , it is proposed that this technique can be considered as a definitive surgery in terms of reducing the risk of secondary operations which will further increase the mortality and morbidity and reduce the quality of life .
we believe that hemiarthroplsty resolves both mechanical and biological problems in unstable trochanteric fractures at the same time . in conclusion ,
calcar preservation arthroplasty is a good treatment option for elderly patients with unstable intertrochanteric fractures , severe osteoporosis , frail constitution and who have high risk of secondary operations .
although the number of cases is low in this study , the desired results were obtained in the early and middle postoperative period . | backgroundthe treatment of unstable intertrochanteric fractures in elderly is still controversial .
the purpose of this study is to present treatment strategies for unstable intertrochanteric fractures with hemiarthroplasty using standard uncemented collared femoral stems and at the same time preserving the fractured calcar fragment.methodsfifty-four patients aged 75 years or older with unstable intertrochanteric fractures were included in this prospective cohort study .
all patients were treated with calcar preserving hemiarthroplasty using cementless collored femoral stems . fractured calcar fragment
was stabilized either by compaction between the implant and femur or fixed with cable grip system .
follow - up evaluations were performed at least 24 months and later .
palmer and parker mobility score and visual analogue scale ( vas ) pain score were assessed .
we also analyzed radiographs of the operated hip at each follow - up visit.resultsthe patients were 15 males and 39 females with a mean age of 81.3 years ( range , 75 to 93 years ) .
the average operative time was 86.6 minutes .
the mean transfused blood units were 1.2 units .
the average duration of hospital stay was 5.3 days .
the preoperative mean mobility score was 6.20 .
this score was found to be 4.96 on postoperative third day and 5.90 at 24 months postoperatively .
the results of the statistical analysis revealed significant increase in the mobility scores at each follow - up after three days .
radiological interpretation revealed no loosening in the cable - grip systems , and no significant subsidence ( > 5 mm ) of prosthesis was observed.conclusionscalcar preservation arthroplasty is a good option for elderly patients with severe osteoporosis , frail constitution and the patients who are at higher risk for second operation due to unstable intertrochanteric fractures . |
although rare in singapore it is an important cause of morbidity in south eastern asia .
the clinical presentation is of constipation followed by diarrhea with fever , headache , cough and relative bradycardia .
gastrointestinal ( gi ) bleeding is not a common manifestation of typhoid fever and massive hematochezia less so .
our case , the first reported in singapore , illustrates the importance of considering s. typhi as a cause of massive lower gastrointestinal hemorrhage .
a 29 year old filipino female presented with a 10 day history of diarrhea and abdominal pain .
the patient had been employed as a domestic aide in singapore for 2 years and had returned from a trip back to the philippines three months prior to admission .
she was febrile to 39 c , had a heart rate of 98 beats per minute ( bpm ) , and a blood pressure of 98/55 mmhg .
initial investigations revealed a hemoglobin of 10.6 g / dl ( reference range ( rf ) 11.714.7 ) , white cell count of 4.8 ( rf 3.29.8 ) 10 and platelets of 133 ( rf 160398 ) 10 .
her renal function was normal and her liver function tests revealed , albumin 2.9 ( rf 3.84.8 ) g / dl , bilirubin 1.2 mg / dl ( rf 0.31.7 ) , aspartate aminotransferase ( ast ) 112 ( rf 1050 ) u / l , alanine aminotransferase ( alt ) 37 ( rf1070 )
u / l and an alkaline phophatase ( alp ) 543 ( rf 40130 ) u / l .
although stool and urine cultures were negative , her blood culture grew s. typhi sensitive to ceftriaxone and ciprofloxacin .
she underwent an ultrasound scan of her hepatobilliary system in view of her abnormal liver function tests and s. typhi bacteremia .
there were no hepatic space occupying lesions , cholecystitis or biliary duct dilation although a small gallstone and some biliary sludge were present .
she was treated initially with intravenous ceftriaxone and metronidazole , and her diarrhea , fever and abdominal pain resolved .
her alp however remained elevated at 543 u / l which prompted a consideration of endoscopic ultrasound to further evaluate her biliary tract as an outpatient .
she was seen in the emergency department the following day for a large lower gi hemorrhage .
she was pale , dehydrated and had a blood pressure of 100/68 mmhg with a heart rate of 110 bpm .
her hemoglobin had dropped to 6.1 g / dl and her coagulation screen was normal .
she underwent an urgent sigmoidoscopy which revealed a large amount of blood in the rectum , sigmoid and descending colon .
1 ) but no bleeding source was detected . a subsequent colonoscopy revealed terminal ileitis with hypertrophic peyer 's patches , and multiple small ulcers with surrounding inflammation and submucosal hemorrhages ; similar changes were seen in the cecum and ascending colon . a biopsy taken from her sigmoid colon revealed mild focal active colitis .
she continued to bleed actively , ct angiography with a view toward embolization or colectomy were considered in the event of hypotension , a surgical opinion was therefore sought .
she required a total of 10 units of red cell transfusion and although her blood and stool culture was negative she received an additional fourteen days of intravenous ceftriaxone .
the patient was discharged stable after completing her course of antibiotics , with a hemoglobin of 9.2 g / dl .
she did not have a repeat colonoscopy and stool cultures remained negative two months after discharge ( fig .
descriptions of typhoid related lower gi hemorrhage date back to sir william osler 's texts at the turn of the 20th century and a comprehensive analysis of 360 cases in 1946 , .
a report from mexico in 1986 is also noteworthy . in a study of patients with hematochezia secondary to typhoid colitis , lee et al
. demonstrated that the terminal ileum was the most commonly involved site followed by the ileocecal valve , ascending colon , and transverse colon respectively .
they also found that punched out ulcers were common and the left colon was spared .
these findings are consistent with those in our patient although her ulcers were in the sigmoid colon .
we postulate that her bleeding arose in the colon given the endoscopic finding of ulcers , however a terminal ileal source of bleeding is also a possibility .
the possibility that the colonoscopic finding of ulcers portends bleeding should therefore be considered , although data are needed to validate this hypothesis .
s. typhi is a gram negative bacillus which is transmitted via the fecal - oral route and modulates the host immune response to invade intestinal and colonic epithelia .
it proliferates intracellularly , initially in the second part of the peyer 's patches from where it disseminates to the liver , spleen and reticuloendothelial system .
further proliferation occurs in these organs over the next seven to 21 days following which organisms are released into the bile and re - infect the ileal lymphoid tissue leading to the classical bowel pathology associated with s. typhi infection .
it is noteworthy that s. typhi bacteremia was reported in several patients with massive hematochezia , one series described three patients , all of whom were bacteremic .
it is possible that disseminated s. typhi may be a risk factor for lower gastrointestinal bleeding , however more data are required to confirm this , especially since many of the older reports do not include blood culture results .
it may also be of interest to ascertain the frequency of gastrointestinal bleeding with infection by different subtypes of the organism , another area with a paucity of clinical data .
the management of gastrointestinal bleeding secondary to s. typhi is largely conservative and as in our patient , appropriate antimicrobial therapy with hemodynamic and transfusion support is usually adequate .
the antimicrobial of first choice is ceftriaxone with fluoroquinolones a second option if a sensitive strain is detected . in cases of severe , life threatening hemorrhage , more invasive measures may be required to control the bleeding .
the successful use of selective angiography and platinum coil embolization to manage massive lower gastrointestinal bleeding due to s. typhi has been reported from the united kingdom . given
that enteric fever is largely a disease of the developing world , many centers may not have access to radiological intervention , possibly accounting for the lack of more data in this area .
surgical intervention can be an important option and can be life saving if bleeding is refractory to conservative therapy .
the pathological processes underlying the bleeding may have been in progress during or even before her initial admission .
it should therefore be considered whether the events of the second admission could have been foreseen .
bacteremia may be considered a predictive factor for colitis and bleeding given that some reports suggest an association .
other potential predictive factors may include systemic inflammatory response syndrome criteria and hepatosplenomegaly , which indicate disseminated disease .
bacteremic patients may therefore be considered for longer in patient observation and closer outpatient follow up after discharge .
our case illustrates that s. typhi should be considered in the differential diagnosis of massive lower gastrointestinal hemorrhage , especially in the setting of recent travel in south or south east asia .
early clinical suspicion and initiation of appropriate antibiotics could be crucial in the final outcome of patients affected by this unusual complication of typhoid fever . | we present a case of massive lower gastrointestinal hemorrhage secondary to salmonella enterica subtype typhi ( s. typhi ) colitis , in a 29 year - old female treated for s. typhi bacteremia . one week post - treatment , she unexpectedly developed a large volume of rectal bleeding .
endoscopy showed colonic ulcers and ileitis , but no endoscopic hemostasis was required .
treatment was supportive with transfusions and a prolonged course of antimicrobials , with the bleeding stopping spontaneously .
this case illustrates the phenomenon of delayed lower gastrointestinal hemorrhage , as a rare complication of s. typhi infection . |
arterial stiffness ( as ) is an early manifestation of adverse structural and functional changes in the vessel wall , which are related to a wide spectrum of major clinical endpoints including atherosclerosis , hypertension ( ht ) , diabetes mellitus ( dm ) , chronic renal disease , valvular heart disease , hypertrophic cardiomyopathy , congenital heart disease , and connective tissue disorders.1 ) increased arterial stiffness is known to be associated with several cardiovascular risk factors such as hypercholesterolemia , ht , dm , metabolic syndrome , and obesity.1 ) as has been reported as an important predictor of cardiovascular ( cv ) morbidity and mortality in both the general population and in people with the obstructive sleep apnea syndrome ( osas).2 ) numerous ultrasonographic parameters - including pulse wave velocity ( pwv ) , carotid artery intima - media thickness ( cimt ) , and flow - mediated dilatation ( fmd)-can be used to identify arterial stiffness at an early stage.3 ) osas is a condition characterized by repetitive episodes of complete or partial obstruction of the upper airway during sleep .
the important role of osas in the initiation and progression of atherosclerosis and increased arterial stiffness has been reported in a recent study.4 ) osas is also related to major adverse outcomes in various cardiovascular diseases .
this is because these episodes of obstruction cause a reduction in the supply of oxygen to vital organs and also irregularity in cardiovascular rhythms.5 ) in previous studies , aortic stiffness has been associated with both the presence and the severity of osas.6 ) it has recently been reported that color m - mode - derived propagation velocity measured along the origin of the descending thoracic aorta ( aortic velocity propagation , avp ) is associated with atherosclerosis , coronary artery disease , coronary slow flow , and type 2 diabetes mellitus.7)8)9 ) in the atherosclerotic vessel walls , increased aortic resistance secondary to atherosclerosis may be reflected in a decrease in the flow propagation speed within the arterial lumen .
the aims of the present study were to investigate the relationship between avp and atherosclerosis , the association of avp with pwv , cimt , and fmd , and to investigate whether avp can be used as a parameter of as in patients with osas .
a total of 150 patients , who were admitted to outpatient clinics of the university hospital with a diagnosis of osas between march and october 2014 consecutively , and 120 age and gender - matched control subjects were included in this study .
the diagnosis of osas , in this case , had been based on the defined criteria specific to this study.10 ) the control group composed of consecutive subjects , based on a clinical referral , suspected of having osa admitted to the sleep laboratory at the university hospital , for overnight sleep observation ( polysomnography ) between march and october 2014 .
the exclusion criteria for the present study were as follows : moderate to severe renal or hepatic diseases ( n=5 ) , advanced coronary artery disease ( n=9 ) , aortic aneurysm or aortic tortuousity ( n=3 ) , uncontrolled hypertension ( n=8 ) , valvular heart disease ( n=7 ) , hemodynamically significant ventricular arrhythmias ( n=3 ) , atrial fibrillation ( n=4 ) , malignancies ( n=2 ) , acute or chronic inflammatory disease ( n=5 ) , hematologic disorders or blood viscosity problems ( n=2 ) , inadequate echocardiographic image quality ( n=12 ) and patients with uncontrolled respiration during procedure ( n=4 ) . after applying this exclusion criterion ,
the patients with osas were also categorized according to their apnea - hypopnea index ( ahi ) as follows : mild to moderate degree ( ahi 5 - 30 ) and severe degree ( ahi30 ) . demographic and clinical characteristics of the study groups included age , gender , neck circumference , waist circumference , and body mass index ( bmi ) . also , their medical histories for well known risk factors for atherosclerosis such as hypertension , diabetes mellitus , and smoking were collected .
other determinant factors that were considered included medicationsthat used for hypertension and diabetes , epworth sleepiness scale scores , and a collection of medical histories regarding sleep habits from the patient records .
posteroanterior chest x - rays , respiratory function tests , and electrocardiography , which were performed before polysomnography ( psg ) , were assessed .
the eligible patients , who were between 18 and 80 years , were all able to provide a written informed consent as a prerequisite for enrollment .
this study complies with the declaration of helsinki , and the trial protocol was approved by the local ethics committee .
the system had 2 channels of electrooculography , 4 channels of electroencephalography ( eeg ) ( with electrode placements at c4-a1 , c3-a2 , o2-a1 , and o1-a2 ) , sub - mental electromyelography ( emg ) , tibial emg , oro - nasal air flow , pulse oximeter oxygen saturation , thoracic and abdominal movements , body position detector , tracheal sound , and electrocardiogram .
hypopnea was defined as a reduction>30% in airflow lasting more than 10 seconds accompanied by > 4% desaturation and/or arousal .
the average number of episodes of apnea and hypopnea per hour of sleep were measured according to the ahi .
sleep stages were scored following standard criteria with 30-second epochs and were reviewed and verified by a certified sleep physician .
the two - dimensional transthoracic echocardiographic examination was performed at rest and according to established standards .
this method was preferable because of its non - invasiveness , high accuracy , and speediness in assessing the overall condition of the heart .
the factors evaluated include the strength of the heart , the condition of the endocardium , heart valves , and the aorta .
the examination was intended to diagnose a variety of other findings - hypertrophy , cardiac tumors , diastolic function , ventricular dyssynchrony , etc .
the examination was performed using a commercially available echocardiographic device ( vivid 3 , general electric , chicago , il , usa ) with a 3.0-mhz transducer and with the patient in the left lateral decubitus position .
the echocardiogram was performed by two experienced cardiologists who were totally unaware of the clinical data and ongoing medical therapy .
avp measurement was performed using a commercially available echocardiographic device ( vivid 3 , general electric , chicago , il , usa ) with a 3.0-mhz transducer . from a suprasternal window and in a supine position , color m - mode doppler recordings ( vivid 3 , general electric , chicago , il , usa ) were obtained with the cursor parallel to the main flow of direction in the descending aorta . the color doppler nyquist limit was adapted to 30 - 50 cm / s , switching to the m - mode with a recorder sweep rate of 200 mm / s .
an m - mode spatiotemporal velocity map in the shape of a flame is displayed ( fig .
if the slope of the flame was unclear , baseline shifting was used to change the aliasing velocity until a clear delineation of the velocity slope was seen .
the aortic flow propagation velocity was then calculated by dividing the distance between points corresponding to the beginning and end of the propagation slope by the duration between corresponding time points .
thus , avp corresponds to the velocity at which the flow is propagating down the artery .
the avp was chosen because of its simplicity , feasibility , reproducibility , sensitivity , and acceptable specificity .
this examination was also found to be handy in cardiovascular risk estimation and selection of high - risk candidates who needed additional exams .
the avp is also a non - invasive examination , making it suitable for the volunteering subjects of this study .
pwv was measured non - invasively by using the commercially available device ( vp-2000 , colins , kyoto , japan ) .
pwv measurements were performed by a single well - trained clinical technician at the supine position in a quiet and temperature controlled room after at least 10 minutes of rest .
pulsed - wave doppler recordings ( vp-2000 , colins , kyoto , japan ) were acquired from the descending thoracic artery at the origin of the subclavian artery and the left common femoral artery in the supine position .
wave front arrival at each location was defined by extrapolation of the ascending doppler flow profile to the baseline using the electrocardiographic r - wave ( marquette case , hellige medical system , cardiosmart , hellige instrument company , freiburg , germany ) as a time reference .
the descending aortofemoral pwv was determined by dividing the distance ( measured on the body surface using a tape measure ) by the time delay between two points .
the mean of five successive readings to cover a complete respiratory cycle was used in the analysis .
intima - media thickness ( imt ) of the subjects ' bilateral common carotid arteries was measured longitudinally with a 7-mhz transducer attached to an available machine ( vivid 3 , ge medical systems , horten , norway ) .
the bulb dilation served as a landmark to indicate the border between the distal common carotid artery and the carotid bulb .
images were obtained from the distal portion of the common carotid artery , 1 - 2 cm proximal to the carotid bulb .
the two bright echogenic lines in the arterial wall were identified as the tunica intima and tunica media lines .
the intima - media thickness was measured as the distance from the main edge of the first to the main edge of the second echogenic line .
only the far wall intima - media thickness of the distal 1 cm portion of the common carotid artery , just before bifurcation , was measured at the end - diastole ( peak of the r - wave of ecg ) .
images showing the maximum intima - media thickness were stored in a digitized fashion , and cimt measurements were made offline .
each measurement was repeated three times , and the mean of the left and right common carotid arteries was used for analysis .
plaques ( defined as 50% localized thickening of the intima compared to the rest of the wall or as an endoluminal protrusion of the arterial lumen of 0.5 mm ) were not included in the measurement of cimt .
the flow - mediated dilatation of the brachial artery was measured to assess endothelial function .
fmd was measured using ultrasound unit electronic calipers ( vivid 7 , general electric , waukesha , wi , usa ) and a 10-mhz linear array transducer .
they were kept in a supine position at a stable room temperature between 20 and 25 during the ultrasonographic examination .
to best visualize the brachial artery , the arm was comfortably immobilized in the extended position , and the brachial artery was scanned in a longitudinal section 3 - 5 cm above the antecubital fossa .
after optimal transducer positioning , the skin was marked for reference for later measurements , and the arm was kept in the same position throughout the study .
all measurements of the brachial artery lumen diameter were assessed at the end - diastole ( timed by the qrs complex ) and were calculated as the average of the measurements obtained during three consecutive cardiac cycles . after recording baseline measurements , the cuff was inflated to 200 mmhg ( or 50 mmhg higher than systolic blood pressure ) for 5 minutes to create a transient forearm ischemia .
subsequently , the cuff was deflated , and the arterial diameter was measured at 30 , 60 , 90 , and 180 seconds after deflation .
the maximum diameter in each of these measurements was used in the calculation of fmd according to the following formula : ( maximum diameter during reactive hyperemia - diameter at baseline)100/(diameter at baseline ) .
sixty patients were randomly included and pearson correlation analysis was performed to assess intra- and interobserver variability .
intraobserver variability for avp , fmd , pwv and cimt were 3.42.9% ( r=0.89 ) , 3.83.4% ( r=0.87 ) , 2.82.3% ( r=0.88 ) and 1.90.8% ( r=0.89 ) respectively ( all p>0.05 ) .
moreover , interobserver variability for avp , fmd , pwv and cimt were 3.63.5% ( r=0.88 ) , 4.13.7% ( r=0.86 ) , 3.12.9% ( r=0.87 ) and 2.11.1% ( r=0.91 ) respectively ( all p>0.05 ) .
differences between independent groups were assessed by student 's t - test for normally distributed quantitative variables , mann - whitney 's u - test for variables without a normal distribution , and the chi - square test for qualitative variables .
all tests were performed with spss for windows , version 10.0 ( spss inc . ,
a total of 150 patients , who were admitted to outpatient clinics of the university hospital with a diagnosis of osas between march and october 2014 consecutively , and 120 age and gender - matched control subjects were included in this study .
the diagnosis of osas , in this case , had been based on the defined criteria specific to this study.10 ) the control group composed of consecutive subjects , based on a clinical referral , suspected of having osa admitted to the sleep laboratory at the university hospital , for overnight sleep observation ( polysomnography ) between march and october 2014 .
the exclusion criteria for the present study were as follows : moderate to severe renal or hepatic diseases ( n=5 ) , advanced coronary artery disease ( n=9 ) , aortic aneurysm or aortic tortuousity ( n=3 ) , uncontrolled hypertension ( n=8 ) , valvular heart disease ( n=7 ) , hemodynamically significant ventricular arrhythmias ( n=3 ) , atrial fibrillation ( n=4 ) , malignancies ( n=2 ) , acute or chronic inflammatory disease ( n=5 ) , hematologic disorders or blood viscosity problems ( n=2 ) , inadequate echocardiographic image quality ( n=12 ) and patients with uncontrolled respiration during procedure ( n=4 ) . after applying this exclusion criterion ,
the patients with osas were also categorized according to their apnea - hypopnea index ( ahi ) as follows : mild to moderate degree ( ahi 5 - 30 ) and severe degree ( ahi30 ) . demographic and clinical characteristics of the study groups included age , gender , neck circumference , waist circumference , and body mass index ( bmi ) . also , their medical histories for well known risk factors for atherosclerosis such as hypertension , diabetes mellitus , and smoking were collected .
other determinant factors that were considered included medicationsthat used for hypertension and diabetes , epworth sleepiness scale scores , and a collection of medical histories regarding sleep habits from the patient records .
posteroanterior chest x - rays , respiratory function tests , and electrocardiography , which were performed before polysomnography ( psg ) , were assessed .
the eligible patients , who were between 18 and 80 years , were all able to provide a written informed consent as a prerequisite for enrollment .
this study complies with the declaration of helsinki , and the trial protocol was approved by the local ethics committee .
the system had 2 channels of electrooculography , 4 channels of electroencephalography ( eeg ) ( with electrode placements at c4-a1 , c3-a2 , o2-a1 , and o1-a2 ) , sub - mental electromyelography ( emg ) , tibial emg , oro - nasal air flow , pulse oximeter oxygen saturation , thoracic and abdominal movements , body position detector , tracheal sound , and electrocardiogram .
hypopnea was defined as a reduction>30% in airflow lasting more than 10 seconds accompanied by > 4% desaturation and/or arousal .
the average number of episodes of apnea and hypopnea per hour of sleep were measured according to the ahi .
sleep stages were scored following standard criteria with 30-second epochs and were reviewed and verified by a certified sleep physician .
the two - dimensional transthoracic echocardiographic examination was performed at rest and according to established standards .
this method was preferable because of its non - invasiveness , high accuracy , and speediness in assessing the overall condition of the heart .
the factors evaluated include the strength of the heart , the condition of the endocardium , heart valves , and the aorta .
the examination was intended to diagnose a variety of other findings - hypertrophy , cardiac tumors , diastolic function , ventricular dyssynchrony , etc .
the examination was performed using a commercially available echocardiographic device ( vivid 3 , general electric , chicago , il , usa ) with a 3.0-mhz transducer and with the patient in the left lateral decubitus position .
the echocardiogram was performed by two experienced cardiologists who were totally unaware of the clinical data and ongoing medical therapy .
avp measurement was performed using a commercially available echocardiographic device ( vivid 3 , general electric , chicago , il , usa ) with a 3.0-mhz transducer . from a suprasternal window and in a supine position , color m - mode doppler recordings ( vivid 3 , general electric , chicago , il , usa ) were obtained with the cursor parallel to the main flow of direction in the descending aorta . the color doppler nyquist limit was adapted to 30 - 50 cm / s , switching to the m - mode with a recorder sweep rate of 200 mm / s .
an m - mode spatiotemporal velocity map in the shape of a flame is displayed ( fig .
if the slope of the flame was unclear , baseline shifting was used to change the aliasing velocity until a clear delineation of the velocity slope was seen .
the aortic flow propagation velocity was then calculated by dividing the distance between points corresponding to the beginning and end of the propagation slope by the duration between corresponding time points .
thus , avp corresponds to the velocity at which the flow is propagating down the artery .
the avp was chosen because of its simplicity , feasibility , reproducibility , sensitivity , and acceptable specificity .
this examination was also found to be handy in cardiovascular risk estimation and selection of high - risk candidates who needed additional exams .
the avp is also a non - invasive examination , making it suitable for the volunteering subjects of this study .
pwv was measured non - invasively by using the commercially available device ( vp-2000 , colins , kyoto , japan ) .
pwv measurements were performed by a single well - trained clinical technician at the supine position in a quiet and temperature controlled room after at least 10 minutes of rest .
pulsed - wave doppler recordings ( vp-2000 , colins , kyoto , japan ) were acquired from the descending thoracic artery at the origin of the subclavian artery and the left common femoral artery in the supine position .
wave front arrival at each location was defined by extrapolation of the ascending doppler flow profile to the baseline using the electrocardiographic r - wave ( marquette case , hellige medical system , cardiosmart , hellige instrument company , freiburg , germany ) as a time reference .
the descending aortofemoral pwv was determined by dividing the distance ( measured on the body surface using a tape measure ) by the time delay between two points .
the mean of five successive readings to cover a complete respiratory cycle was used in the analysis .
intima - media thickness ( imt ) of the subjects ' bilateral common carotid arteries was measured longitudinally with a 7-mhz transducer attached to an available machine ( vivid 3 , ge medical systems , horten , norway ) .
the bulb dilation served as a landmark to indicate the border between the distal common carotid artery and the carotid bulb .
images were obtained from the distal portion of the common carotid artery , 1 - 2 cm proximal to the carotid bulb .
the two bright echogenic lines in the arterial wall were identified as the tunica intima and tunica media lines .
the intima - media thickness was measured as the distance from the main edge of the first to the main edge of the second echogenic line .
only the far wall intima - media thickness of the distal 1 cm portion of the common carotid artery , just before bifurcation , was measured at the end - diastole ( peak of the r - wave of ecg ) .
images showing the maximum intima - media thickness were stored in a digitized fashion , and cimt measurements were made offline .
each measurement was repeated three times , and the mean of the left and right common carotid arteries was used for analysis .
plaques ( defined as 50% localized thickening of the intima compared to the rest of the wall or as an endoluminal protrusion of the arterial lumen of 0.5 mm ) were not included in the measurement of cimt .
the flow - mediated dilatation of the brachial artery was measured to assess endothelial function .
fmd was measured using ultrasound unit electronic calipers ( vivid 7 , general electric , waukesha , wi , usa ) and a 10-mhz linear array transducer .
they were kept in a supine position at a stable room temperature between 20 and 25 during the ultrasonographic examination .
to best visualize the brachial artery , the arm was comfortably immobilized in the extended position , and the brachial artery was scanned in a longitudinal section 3 - 5 cm above the antecubital fossa .
after optimal transducer positioning , the skin was marked for reference for later measurements , and the arm was kept in the same position throughout the study .
all measurements of the brachial artery lumen diameter were assessed at the end - diastole ( timed by the qrs complex ) and were calculated as the average of the measurements obtained during three consecutive cardiac cycles . after recording baseline measurements , the cuff was inflated to 200 mmhg ( or 50 mmhg higher than systolic blood pressure ) for 5 minutes to create a transient forearm ischemia .
subsequently , the cuff was deflated , and the arterial diameter was measured at 30 , 60 , 90 , and 180 seconds after deflation .
the maximum diameter in each of these measurements was used in the calculation of fmd according to the following formula : ( maximum diameter during reactive hyperemia - diameter at baseline)100/(diameter at baseline ) .
sixty patients were randomly included and pearson correlation analysis was performed to assess intra- and interobserver variability .
intraobserver variability for avp , fmd , pwv and cimt were 3.42.9% ( r=0.89 ) , 3.83.4% ( r=0.87 ) , 2.82.3% ( r=0.88 ) and 1.90.8% ( r=0.89 ) respectively ( all p>0.05 ) .
moreover , interobserver variability for avp , fmd , pwv and cimt were 3.63.5% ( r=0.88 ) , 4.13.7% ( r=0.86 ) , 3.12.9% ( r=0.87 ) and 2.11.1% ( r=0.91 ) respectively ( all p>0.05 ) .
differences between independent groups were assessed by student 's t - test for normally distributed quantitative variables , mann - whitney 's u - test for variables without a normal distribution , and the chi - square test for qualitative variables .
all tests were performed with spss for windows , version 10.0 ( spss inc . ,
a total of 206 patients ( 116 patients with osas and 90 control subjects ) were included in the present study .
baseline demographic , clinical , echocardiographic , and laboratory characteristics of the study groups were presented in table 1 .
as we expected , waist circumferences were found to be significantly higher in the osas group compared to controls ( p=0.034 ) .
ahi was found to be higher in the osas group compared to controls ( 31.316.9 vs. 2.341.52 , p<0.001 ) , while the rate of minimal and mean oxygen saturations were found to be decreased in patients with osas compared to control group ( 79.89.3 vs. 91.12.7 , p<0.001 and 89.72.7 vs. 94.21.8 , p<0.001 respectively )
. moreover , left atrial diameter ( p=0.012 ) and left ventricular mass ( p=0.023 ) were significantly higher in the osas group compared to controls .
the e / a ratio was significantly lower in the osas group compared to controls ( p=0.013 ) .
there was no difference between the two groups in terms of other baseline characteristics . in the subgroup analysis of osas patients , waist circumference , left atrial diameter , left ventricular mass and e / a ratio were demonstrated significantly higher in the severe osas group compared to the mild to moderate group ( p=0.048 , p=0.032 , p=0.036 , and p=0.027 respectively ) .
furthermore , avp was found to be significantly lower in the severe osas group compared to the mild to moderate osas group ( 36.211.8 vs. 4612.3 ; p<0.001 ) .
fmd was also lower in the severe group compared to the mild to moderate group ( 7.93.8 vs. 10.34.3 ; p<0.001 ) .
in addition , pwv was significantly higher in the severe osas group compared to the mild to moderate group ( 11.42.2 vs.8.82.0 ; p<0.001 ) .
cimt was also found to be significantly increased in the severe osas group compared to the mild to moderate osas group ( 0.890.18 vs. 0.770.16 ; p<0.005 ) .
patients with osas had significantly lower avp ( 45.816.1 vs. 60.713.6 cm / s , p<0.001 ) ( fig .
2 ) and fmd ( 8.73.3 vs. 14.64.6 % , p<0.001 ) and higher pwv ( 10.32.2 vs. 8.52.0 m / s , p<0.001 ) and cimt ( 0.830.14 vs. 0.660.15 mm , p<0.001 ) than the control subjects ( table 2 ) .
when the association between avp and ahi was investigated , a significant inverse relation was found between them ( r=-0.271 , p<0.001 ) ( fig .
moreover , avp was found to be significantly positively correlated with fmd ( r=0.564 , p<0.001 ) ( fig .
4a ) . however , it was significantly inversely correlated with pwv ( r=-0.580 , p<0.001 ) ( fig .
, avp was found to be significantly inversely correlated with age ( r=-0.125 ; p<0.001 ) .
when the relationship between avp and parameters of diastolic dysfunction was investigated ; it was found to be significantly positively correlated with e / a ( r=0.073 ; p<0.001 ) and negatively correlated with deceleration time ( r=-0.189 ; p<0.001 ) and isovolumetric relaxation time ( r=-0.217 ; p<0.001 ) .
osas is reported to be associated with various cardiovascular diseases , including hypertension , coronary artery disease , atrial fibrillation , cerebrovascular disease , and heart failure.11 ) recent studies have reported an important effects of osas , which is accompanied by recurrent hypoxia , arousals from sleep and generation of raised intrathoracic pressure , on cardiovascular system via several pathways such as sympathetic activation , inflammation , oxidative stress , endothelial dysfunction , and arterial stiffness.12 ) arterial stiffness , a biomarker of vascular aging , is an important risk factor for the development of atherosclerosis and other cardiovascular diseases .
furthermore , arterial stiffness has been reported to be associated with cardiovascular risk factors such as smoking , obesity , hypertension , hypercholesterolemia , diabetes , and advanced age.10)11)12 ) arterial stiffness is an independent predictor of fatal and non - fatal cardiovascular events in patients with osas.13 ) a noninvasive assessment of as with many different parameters has been reported in a previous study.14 ) pwv measurement between the carotid and femoral artery is the gold standard method for the evaluation of arterial stiffness.15 ) it is measured using pressure or volume pulse wave analysis with a transducer.14 ) pwv was reported to be an important independent risk factor for coronary and peripheral atherosclerosis.16 ) moreover , there is marked evidence to indicate that pwv is a strong predictor of cardiovascular events in patients with osas.13 ) a recent study has demonstrated the association of increased pwv with osas.6 ) cimt is a strong marker of subclinical atherosclerosis .
increased cimt has been found to be related to many cardiovascular risk factors , the severity of coronary atherosclerosis , and major adverse cardiovascular events.17 ) a few studies have focused on structural and functional modifications to the large arteries in osas , with the majority of them reporting increases in cimt and pwv.18)19 ) an important direct effect of osas on cimt has been revealed by the studies of silvestrini et al.18 ) and schulz et al.19 ) in our study , cimt and pwv values were demonstrated to be increased in patients with osas compared with age and gender - matched control subjects .
similarly , cimt and pwv were also found to be significantly increased in the severe osas group compared to the mild to moderate osas group .
brachial artery fmd has recently begun to be frequently used in a study of arterial physiology.20 ) an impaired fmd response may reflect a vascular phenotype prone to atherosclerosis .
the usefulness of fmd in predicting the risk of atherosclerosis of osas patients has been evaluated in a few studies.21)22 ) however , the defined procedures for the measurement of as including carotid femoral or aortofemoral pwv , fmd , and cimt are time consuming and not practical in daily practice .
it has been shown that endothelial dysfunction might be affected by nocturnal hypoxemia in osas patients.21 ) many recent studies have also reported that decreased o2 saturation is a significant predictor for endothelial dysfunction.21)22 ) on the other hand , fmd of the brachial artery is a functional marker of endothelial function .
an important inverse relation between fmd and cimt has been defined in some studies.20 ) in our study , concomitant with previous studies , we demonstrated a significant negative association between fmd and cimt .
moreover , fmd was found to be decreased in the severe osas group compared to the mild to the moderate group .
arterial stiffness is mainly determined by structural or functional components of elastic properties , and blood pressure may have an influence on the structure .
since elastic fibers are the main load - bearing components of the arterial wall , the disruption of the elastic properties could be responsible for arterial stiffness.23 ) in our study , we hypothesized that color m - mode propagation velocity measured along the origin of the descending thoracic aorta may reflect arterial stiffness .
the flow propagation speed within the ventricle decreases in the presence of a stiffer ventricle .
similarly , shandas et al.24 ) reported a significant relation between the color m - mode derived velocity propagation of the main pulmonary artery and downstream resistance .
the main finding of the present study was the use of avp as a new echocardiographic parameter for arterial stiffness in patients with osas .
while avp was found to be decreased and was significantly related with pwv , cimt , and fmd in patients with osas , it was inversely associated with ahi . moreover ,
avp was demonstrated to be significantly directly or inversely related with some left ventricular diastolic dysfunction parameters in patients with osas .
avp was significantly lower in the severe osas group compared to the mild to moderate osas group .
because the increased aortic resistance acts in a similar manner to decrease the flow propagation speed within the arterial lumen , a similar decrease in aortic flow propagation with increased downstream resistance is logical .
the decreased avp in patients with osas , which was demonstrated in our study , may be due to increased arterial stiffness and resistance in arterial wall and lumen of vessels .
moreover , aortic and arterial stiffness have been associated with the presence and the severity of osas in a recent study.6 ) it was also reported that continuous hypoxia , which may be encountered in osas , may alter the structure and function of aorta by decreasing the aortic glycosaminoglycans and collagen , or modifying arterial smooth muscle cells.25 ) avp was demonstrated to be the most significant predictor of stable coronary artery disease ( cad ) among clinical and echocardiographic variables ; an avp value of 41 cm / sec had a sensitivity of 82.4% , a specificity of 97.2% , and positive and negative predictive values of 98.7% and 68.2% for the prediction of cad , respectively.26 ) these findings revealed that the avp could be used as an indicator of arterial stiffness in patients with stable cad . in our study , avp was shown to be correlated with the parameters of arterial stiffness ( such as pwv , cimt , and fmd ) in patients with osas .
moreover , avp was found to be significantly lower in the severe osas group compared to the mild to the moderate group .
several recent studies have addressed the methodological issues for various ultrasonographic indices of arterial stiffness .
they reported that methods including aortic distensibility , compliance , pulse pressure , augmentation index , and pwv were difficult to use in daily practice.27 ) however , measurement of avp , which was initially demonstrated to be related to parameters of arterial stiffness in osas in our study is a noninvasive , practical , easy - to - use , and less time - consuming method compared to previous methods .
avp has some limitations due to a high standard deviation , which indicates that scores were widely spread .
gne et al.28 ) found the avp of 33.813.2 in patients with cad and of 66.615.6 in healthy subjects with a p - value of 0,001 .
moreover , the avp was found to be higher in patients with cad compared to controls with a different standard deviation in the study conducted by guntekin et al .
( 44.718.2 vs. 63.111.5 , p<0,001).29 ) the avp was also found 46.412.4 in end - stage renal disease and 58.58.5 in controls in the study of sahin et al.30)(p<0.001 ) .
this variation of avp levels in different studies may due to several factors such as different anatomy of aorta such as aortic tortuousity or aneursym , loading conditions , variations in systolic and diastolic blood pressure , state of taking anti - hypertensive and class of drug , variations in heart rate , different range of valvular heart diseases such as aortic valve regurgitation , different properties of blood viscosity , imaging quality and respiration control during measurement of avp .
the limited echocardiographic image quality may hinder not only the measurement of avp but also the reproducibility of the acquisition and the reading methods . moreover , loading conditions , systolic and diastolic blood pressure as well as the anatomy of the aorta may have an impact on echocardiographic measurements such as avp .
large scale population studies are needed to confirm the applicability of the method as a screening tool .
because of ethical considerations , patients were included under concurrent medications , and this might have had an influence on the precision of the avp measurements .
a lack of measurement of nocturnal oxygen saturation was another limitation of the present study . despite these limitations
, we could confirm that risks for cardiovascular diseases were increased in patients with osas by observing the increased arterial stiffness , impaired endothelial function and decreased avp measurements .
also , in as much as the transthoracic echocardiography availed a detailed profile on the condition of the subject 's heart and arteries , the transesophageal echocardiography ( tee ) would have given a more accurate profile because it would enable closer visualization of other abnormalities ( including those at the back of the heart ) such as prosthetic heart valves and otherwise " invisible " clots within the heart 's chambers .
we have demonstrated that avp is a novel echocardiographic parameter for measuring arterial stiffness in patients with osas .
for the first time , avp was found to be related to parameters of arterial stiffness such as pwv , cimt , and fmd in this setting .
avp measurement may be a novel and practical echocardiographic method for assessing arterial stiffness , which is associated with cardiovascular risk factors in osas .
we hope the findings of this study will shed light on similar research involving the parameters of arterial stiffness in patients with osas .
the limited echocardiographic image quality may hinder not only the measurement of avp but also the reproducibility of the acquisition and the reading methods . moreover , loading conditions , systolic and diastolic blood pressure as well as the anatomy of the aorta may have an impact on echocardiographic measurements such as avp .
large scale population studies are needed to confirm the applicability of the method as a screening tool .
because of ethical considerations , patients were included under concurrent medications , and this might have had an influence on the precision of the avp measurements .
a lack of measurement of nocturnal oxygen saturation was another limitation of the present study . despite these limitations
, we could confirm that risks for cardiovascular diseases were increased in patients with osas by observing the increased arterial stiffness , impaired endothelial function and decreased avp measurements .
also , in as much as the transthoracic echocardiography availed a detailed profile on the condition of the subject 's heart and arteries , the transesophageal echocardiography ( tee ) would have given a more accurate profile because it would enable closer visualization of other abnormalities ( including those at the back of the heart ) such as prosthetic heart valves and otherwise " invisible " clots within the heart 's chambers .
we have demonstrated that avp is a novel echocardiographic parameter for measuring arterial stiffness in patients with osas . for the first time , avp was found to be related to parameters of arterial stiffness such as pwv , cimt , and fmd in this setting .
avp measurement may be a novel and practical echocardiographic method for assessing arterial stiffness , which is associated with cardiovascular risk factors in osas .
we hope the findings of this study will shed light on similar research involving the parameters of arterial stiffness in patients with osas . | background and objectivesobstructive sleep apnea syndrome ( osas ) is associated with increased arterial stiffness and cardiovascular complications .
the objective of this study was to assess whether the color m - mode - derived propagation velocity of the descending thoracic aorta ( aortic velocity propagation , avp ) was an echocardiographic marker for arterial stiffness in osas.subjects and methodsthe study population included 116 patients with osas and 90 age and gender - matched control subjects .
the patients with osas were categorized according to their apnea hypopnea index ( ahi ) as follows : mild to moderate degree ( ahi 5 - 30 ) and severe degree ( ahi30 ) .
aortofemoral pulse wave velocity ( pwv ) , carotid intima - media thickness ( cimt ) , brachial artery flow - mediated dilatation ( fmd ) , and avp were measured to assess arterial stiffness.resultsavp and fmd were significantly decreased in patients with osas compared to controls ( p<0.001 ) .
pwv and cimt were increased in the osas group compared to controls ( p<0.001 ) .
moreover , avp and fmd were significantly decreased in the severe osas group compared to the mild to moderate osas group ( p<0.001 ) .
pwv and cimt were significantly increased in the severe group compared to the mild to moderate group ( p<0.001 ) .
avp was significantly positively correlated with fmd ( r=0.564 , p<0.001 ) .
however , it was found to be significantly inversely related to pwv ( r=-0.580 , p<0.001 ) and cimt ( r=-0.251 , p<0.001).conclusionthe measurement of avp is a novel and practical echocardiographic method , which may be used to identify arterial stiffness in osas . |
an enduring debate amongst breast surgeons concerns the adequacy of excision margins for both invasive and in situ carcinoma ( dcis ) . as yet , no unequivocal consensus has been reached as to what exactly comprises an adequate surgical margin after breast conserving surgery ( bcs ) .
typically , a specimen is excised and then painted or marked according to a protocol to indicate laterality and boundaries . in theory , the histopathologist receives a specimen that can then be orientated such that the location of any residual disease can be identified .
it has been shown that painting specimens at the time of excision are preferable to painting by the pathology department in terms of reexcision rates .
while the national institute for health and clinical excellence ( nice ) suggests reexcision of dcis if the margin is closer than 2 mm , local policies vary as to what is considered an acceptable margin .
surgeons may accept a closer deep margin since the pectoralis fascia is thought to provide and robust anatomical barrier to local spread . at the royal devon and exeter hospital nhs trust ,
policy is to offer reexcision to patients with any margin of invasive cancer within 2 mm and 1 mm for dcis . only in special circumstances
the techniques described above are only valid if the six margins inked upon the excision specimen can be accurately transposed to the surgical cavity such that the area of concern can be targeted in a reexcision procedure , unless a mastectomy is chosen .
this process could be compromised in several ways.no breast excision specimen is a perfect cylinder or six - sided figure .
the margins are in continuum such that the transition from one margin to the next is an imaginary line and must be ascribed by the person painting the specimen.given the shape of the human breast , it is easy to imagine how the shape of an excision may not actually have 6 true faces ; at the edges of a hemisphere , the flat deep face abuts the superficial surface . despite this
, it is customary to always paint on 6 surfaces of an excision specimen.the surgical cavity itself will deform over time on account of postsurgical change , radiotherapy , and surgical manipulation of the cavity.the shape of the surgical cavity will vary with patient positioning and retraction during the reexcision procedure.since the cavity 's margins are in continuum , the surgeon must make a subjective decision as to how large the reexcision margin should be ; imaginary boundaries ascribed to the specimen must also be ascribed to the cavity.evidence exists that even when inked margins are processed in finer detail by margin shaving with multiple field examination , margin involvement is increased .
the margins are in continuum such that the transition from one margin to the next is an imaginary line and must be ascribed by the person painting the specimen . given the shape of the human breast , it is easy to imagine how the shape of an excision may not actually have 6 true faces ; at the edges of a hemisphere , the flat deep face abuts the superficial surface . despite this
the surgical cavity itself will deform over time on account of postsurgical change , radiotherapy , and surgical manipulation of the cavity .
the shape of the surgical cavity will vary with patient positioning and retraction during the reexcision procedure .
since the cavity 's margins are in continuum , the surgeon must make a subjective decision as to how large the reexcision margin should be ; imaginary boundaries ascribed to the specimen must also be ascribed to the cavity .
evidence exists that even when inked margins are processed in finer detail by margin shaving with multiple field examination , margin involvement is increased .
inking margins alone , therefore , is likely to underestimate margin positivity . despite these considerations ,
it is standard practice in most institutions to offer reexcision following bcs if margins are thought to be involved .
if the reexcision specimen contains no cancer , this might be because it was all excised in the original operation , but it might also be because the wrong area of the cavity was targeted in the reexcision procedure .
there is no consensus as to what the impact of reexcision is in terms of local disease recurrence , since this does not lend itself to randomised investigation .
what remains in the literature is a diverse collection of retrospective , observational studies of variable robustness .
some reports suggest decreased disease - free survival in patients who have had reexcisions , while others report no difference [ 5 , 6 ] .
a further study suggested that local failure was commoner only if the reexcision specimen contained cancer , while another shows that local recurrence is similar when reexcision is by ink - directed cavity shaving or entire cavity excision .
these diverse outcomes are perhaps explained by the perpetual problem of observing local recurrence in early breast cancer ; it is rare and takes many years to happen , meaning that they are usually retrospectively designed or underpowered : the latter of these studies was based on only 11 recurrence events over 3.7 years .
whatever the truth about recurrence , a second operation is undesirable in terms of delayed adjuvant treatment , operative risk , and the emotional burden this has on patients . in this experiment
, we aim to quantify , as far as possible , the error inherent in specimen painting , specifically concerning the ascription of margin boundaries and , hence , the surface area of specimen faces .
this information could be used to estimate a border of error to be considered when re - excising cavity margins or even to question the practice altogether .
we were also interested to know whether the order in which the margins were painted made a difference to the surface area ascribed as informal opinion amongst some practitioners suggested that the last surface to be painted often seemed to be larger than the rest .
there is no difference in the surface areas painted on the six faces of each specimen compared to the expected calculated surface areas of the controls .
an experimental model to represent a breast excision specimen was created according to the following criteria.the model must be accurately replicable.the model must test the ability of a person to paint , freehand , six surfaces on an irregular , nonsolid , and 3-dimensional object , using the materials they would normally use for painting breast specimens.the model must be such that its painted surfaces can be scanned on a flatbed scanner.the model must not be a geometrical shape with any identifiable vertices , corners , or angles.the model should retain , as far as possible , the characteristics of human breast tissue ( such as elasticity , malleability , and softness ) , acknowledging that human or animal tissue was not a suitable alternative for ethical , practical , and methodological reasons .
it was also acknowledged that the model need not be a perfect proxy for breast tissue so long as it fulfilled criteria 14 .
the model must be accurately replicable . the model must test the ability of a person to paint , freehand , six surfaces on an irregular , nonsolid , and 3-dimensional object , using the materials they would normally use for painting breast specimens
. the model must be such that its painted surfaces can be scanned on a flatbed scanner .
the model must not be a geometrical shape with any identifiable vertices , corners , or angles .
the model should retain , as far as possible , the characteristics of human breast tissue ( such as elasticity , malleability , and softness ) , acknowledging that human or animal tissue was not a suitable alternative for ethical , practical , and methodological reasons .
it was also acknowledged that the model need not be a perfect proxy for breast tissue so long as it fulfilled criteria 14 .
having experimented with a number of fillers such as gelatine and corn flour paste , water - filled balloons were used to represent breast excision specimens , with the knot representing its most superficial aspect .
it was acknowledged that the balloons could not be under any tension as this might distort the final surface area .
it was found that 70 ml water achieved the desired effect . due to the slight convexity of the cut balloon surfaces ,
relaxing incisions were made after painting so that they could lie flat on the scanner .
three volunteers who routinely paint breast excision specimens were asked to paint the six faces , that is , caudal , medial , cranial , lateral , deep , and superficial as if each was equal in surface area , noting the first and last surfaces to be painted .
the surface areas of each aspect were measured in pixels , after being cut out ( without the knot ) and scanned .
these measurements were compared to the expected surface area derived from a similar process whereby the balloon , unpainted , was scanned and then its total surface area divided by 6 , thereby generating an almost perfect control in which the only variation in surface area would be due to manufacturing variability and the exact level at which the knot was cut off .
the painted surface areas were compared to the control surface areas using a one - way anova with dunnett 's t - test , a priori , multiple comparisons .
four groups of areas were compared : first painted surfaces , last painted surfaces , other painted surfaces , and control surfaces .
the experimental surfaces were compared against the control surfaces with the dunnett t - test .
these were first painted surfaces versus controls , last painted surfaces versus controls , other painted surfaces versus controls .
first painted surfaces versus controls , last painted surfaces versus controls , other painted surfaces versus controls .
statistical analysis was performed using ibm spss statistics 19 , and a p value of < 0.05 was taken to be statistically significant .
it was not uncommon for painted surface areas to differ by as much as 100% ( 30 000 pixels versus 60 000 pixels ) , with some outliers being very much larger in variability .
figure 2 is a standardised histogram ( the experimental areas divided by the mean of the controls ) , which demonstrates that almost 30% of the experimental areas ( 16/54 ) were more than 20% greater or less than the control .
tables 1 and 2 show that no difference was observed in surface areas between the first side painted , the other sides painted , and the controls .
there was a significant difference in the surface areas of the last sides painted and controls ( mean difference 8900 pixels , ci 147716324 , p = 0.014 ) , meaning that the last side painted was on average 18% bigger than the control sides . by chance ,
in this study , we have quantified the magnitude of error in ascribing imaginary boundaries to a breast excision model .
we found enormous variation in the surface areas of the painted surfaces compared to a control and that the last painted surface was consistently 18% larger than the controls . both of these findings raise questions as to whether painting breast excision specimens after bcs and the practice of margin reexcision ( compared to cavity reexcision or mastectomy ) are safe .
as with any experimental model , there are questions about translational validity , but we would submit that the kinds of judgments made by volunteers regarding boundary ascription with the balloon models are not dissimilar to those faced with a real specimen .
we maintain that the problem with painting a breast specimen is not that it is breast tissue , per se , but that it , like the model , is irregular and has no definable shape and confluent surfaces .
the finding that some sides were frequently in the order of 100% larger than other sides is intriguing .
, this might mean including a generous proportion of the surrounding cavity with the reexcision specimen , but we must acknowledge that , as the margins become bigger , the actual amounts of extra tissue are correspondingly smaller as the relationship between surface area and diameter is nonlinear and for an irregular shape would be impossible to calculate precisely . of similar concern is the finding that the last margin painted is consistently larger than the controls and that this was invariably the deep margin , raising the question as to whether a close deep margin can really be ignored as this may in fact be one of the circumferential margins .
this study is the first to attempt to quantify the extent of human error in marking imaginary boundaries on a breast excision model and suggests that humans do not make these judgements well .
it might be argued that the ascription of boundaries on a specimen is only a small part of the overall problem and , given the potential areas for error , the only sensible approach is whole cavity reexcision or mastectomy .
it has shown recently that an approach to bcs using oncoplastic techniques , allowing the surgeon to take larger areas of tissue whilst maintaining breast cosmesis , can result in very considerable reductions in reexcision rates .
another area of interest is the development of technology to allow intraoperative assessment of margins , even before excision is complete as well as devices to improve the orientation of breast specimens . | aim .
when excision margins are close or involved following breast conserving surgery , many surgeons will attempt to reexcise the corresponding cavity margin .
margins are ascribed to breast specimens such that six faces are identifiable to the pathologist , a process that may be prone to error at several stages .
methods .
an experimental model was designed according to stated criteria in order to answer the research question .
computer software was used to measure the surface areas of experimental surfaces to compare human - painted surfaces with experimental controls .
results .
the variability of the hand - painted surfaces was considerable .
thirty percent of hand - painted surfaces were 20% larger or smaller than controls .
the mean area of the last surface painted was significantly larger than controls ( mean 58996 pixels versus 50096 pixels , ci 147716324 , p = 0.014 ) . by chance ,
each of the six volunteers chose to paint the deep surface last . conclusion .
this study is the first to attempt to quantify the extent of human error in marking imaginary boundaries on a breast excision model and suggests that humans do not make these judgements well , raising questions about the safety of targeting single margins at reexcision . |
hepatic resection is still the most effective treatment for hcc ; however , the recurrence rate is very high even after curative resection .
the postoperative 5-year recurrence rate was shown to be higher than 70% , with 80% to 95% of recurrence being confined to the liver [ 14 ] .
intrahepatic recurrence has been classified as either metachronous multicentric - occurrence hcc ( mc ) or intrahepatic metastasis ( i m ) [ 5 , 6 ] . anatomic hepatic resection has been shown to be effective for micro i m within resected sections or segments with progressed hcc [ 79 ] but is ineffective for mc in the remnant liver .
recent studies have shown that hypovascular early hcc ( ehcc ) , which is not an indication for resection , progresses to conventional hypervascular hcc .
hypovascular ehcc is thought to be one of the causes of multicentric recurrence of hypervascular hcc after hepatic resection .
however , the effects of simultaneous treatment of suspected ehcc at the time of hepatic resection for progressed hcc on postoperative recurrence have never been evaluated . a new magnetic resonance imaging ( mri ) contrast medium , gadoxetic acid , or gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid ( gd - eob - dtpa ) ( primovist , bayer healthcare , osaka , japan ) , which has the properties of both an extracellular gadolinium chelate and liver - specific ( hepatocyte - targeting ) contrast material , has become available [ 1013 ] .
our previous study revealed that gd - eob - dtpa - enhanced mri ( eob - mri ) was the most useful imaging technique for evaluating small hcc , including ehcc .
the purpose of this study was to clarify whether preoperative eob - mri and simultaneous treatment of suspected ehcc at the time of resection for progressed hcc affected the overall and recurrence - free survival of patients after initial hepatic resection for hcc .
a total of 147 consecutive progressed hcc patients without extrahepatic metastasis who underwent their first curative hepatic resection for hcc at the first department of surgery ( yamanashi university hospital , yamanashi , japan ) between 1 january 2005 and 31 december 2010 were retrospectively enrolled in this study .
this study protocol followed the ethical guidelines of the declaration of helsinki amended in 2008 , and written informed consent was obtained from each patient .
preoperative imaging studies , including chest radiography , abdominal ultrasonography ( aus ) , computed tomography ( ct ) , mri , hepatic arteriography , ct during arterial portography ( ctap ) , and ct during hepatic arteriography ( ctha ) , were performed .
one patient did not undergo contrast - enhanced ct , ctha , or ctap because of an allergy to the iodinated contrast material .
in addition , ctha and ctap were not performed in one patient with mild renal dysfunction .
, eob - mri has been performed before hepatic resection for hcc as essential imaging diagnostics . in this study
, 77 patients underwent eob - mri ( eob - mri ( + ) group ) and the remaining 70 patients underwent conventional mri ( eob - mri ( ) group ) before hepatic resection for hcc .
hypovascular hepatic nodules showing low attenuation on unenhanced ct and ctap and those showing low signal intensity on hepatocyte - phase images of eob - mri were diagnosed as suspected ehccs [ 13 , 14 ] .
liver function reserve was assessed by liver biochemistry , child - pugh grading , and the indocyanine green retention rate at 15 min ( icgr15 ) .
only patients with child - pugh class a and icgr15 below 20% were offered major hepatic resection , which is defined as resection of two or more segments of the liver according to couinaud 's classification .
patients with child - pugh class a and icgr15 more than 20% and selected class b patients underwent minor hepatic resection , which is defined as resection of one segment or less of the liver . suspected ehccs detected by preoperative imaging diagnosis with or without eob - mri , and being more than 5 mm in diameter , were simultaneously resected or ablated at the time of resection for progressed hcc . all surgically resected specimens were fixed in 10% buffered formaldehyde .
sections of resected tumors and noncancerous livers were embedded in paraffin , sliced into 3 to 5 m thick sections , and were then stained with hematoxylin - eosin for histological analyses .
all suspected ehccs were diagnosed strictly according to the pathological criteria proposed by the international consensus group for hepatocellular neoplasia ( icghn ) by pathologists .
after the initial operation , patients were followed up at 2-week intervals for the first 2 months and monthly thereafter .
serum levels of -fetoprotein ( afp ) , a lens culinaris agglutinin reactive fraction of afp ( afp - l3 ) , and des--carboxy prothrombin ( dcp ) were measured serially at least every 2 months .
imaging diagnosis , using ct or mri , was performed at least every 4 months .
diagnosis of recurrence was made when intrahepatic hypervascular hcc was found by contrast - enhanced ct , mri , or ctha .
if intrahepatic recurrence was 3 nodules and all tumors were potentially resectable in terms of anatomical location and liver function , recurrence was managed using repeat hepatic resection .
recurrence was managed using radiofrequency ablation ( rfa ) if intrahepatic recurrence was solitary and completely ablative and hepatic function of the patient was not suitable for repeat hepatic resection or if the patient refused hepatic resection . multiple intrahepatic recurrence ( > 3 nodules )
continuous data are expressed as the median ( range ) and were compared using the mann - whitney u test .
categorical variables were compared using the chi - square test with yates ' correction or fisher 's exact test where appropriate .
survival was calculated by the kaplan - meier method and compared by means of the log - rank test .
univariate and multivariate analyses were performed using the cox proportional hazards model to identify prognostic factors .
a comparison of background factors between the eob - mri ( + ) and eob - mri ( ) groups was performed ( table 1 ) .
the dcp value of patients in the eob - mri ( ) group was significantly higher than that in the eob - mri ( + ) group ( median : 57 mau / ml ; range : 1230805 mau / ml ; versus 29.0 mau / ml ; 917521 mau / ml ; p = 0.02 ) .
the number of patients who underwent treatment for ehccs at the time of hepatic resection was significantly higher in the eob - mri ( + ) group than in the eob - mri ( ) group ( 17 versus 6 ; p = 0.04 ) .
no significant differences were observed in the other background factors between groups . in the eob - mri ( ) group ,
histologically , 6 out of 8 resected tumors were ehcc and two were dysplastic nodules ( dns ) . on the other hand ,
24 suspected ehccs from 17 patients were treated in the eob - mri ( + ) group ( 23 were resected and one was ablated by microwaves without biopsy ) at the time of the operation .
histological examination revealed that 21 out of 23 resected tumors were ehcc , one was dn , and one was accessory liver . in the eob - mri ( + ) group ,
8 out of 21 ehccs ( 38.1% ) were detected at only hepatocyte phase of eob - mri .
the 1- , 3- , and 5-year overall survival rates of 77 hcc patients in the eob - mri ( + ) group were 98.7 , 90.7 , and 80.8% , respectively , whereas the corresponding survival rates of 70 hcc patients in the eob - mri ( ) group were 97.0 , 86.3 , and 72.4% , respectively ( figure 1 ) .
no significant differences were observed in the overall survival curves between the two groups ( p = 0.38 ) . on the other hand ,
the 1- , 3- , and 5-year recurrence - free survival rates of 77 hcc patients in the eob - mri ( + ) group were 81.4 , 62.6 , and 48.7% , respectively , whereas those of 70 hcc patients in the eob - mri ( ) group were 82.1 , 41.5 , and 25.5% , respectively ( figure 2 ) .
recurrence - free survival after hepatic resection was significantly better in the eob - mri ( + ) group than in the eob - mri ( ) group ( p < 0.01 ) .
tables 2 and 3 summarize the results of univariate analysis of the 20 clinical and laboratory factors and 7 pathological and tumor - related factors , respectively , for overall survival and recurrence - free survival among the 147 patients with hcc following curative hepatic resection . in clinical and laboratory factors , the presence of an esophageal varix ( p = 0.02 ) , platelet count 10 10/l or less ( p < 0.01 ) , child - pugh class b ( p < 0.01 ) , and a dcp value more than 40 mau / ml ( p = 0.03 ) were correlated with significantly worse overall survival ( table 2 ) .
other clinical and laboratory factors did not show any significant influence on overall survival after hepatic resection for hcc . in pathological and tumor - related factors ,
the presence of liver cirrhosis ( p = 0.01 ) was correlated with significantly worse overall survival ( table 3 ) . in clinical and laboratory factors ,
preoperative eob - mri significantly reduced the risk of recurrence ( p < 0.01 ) . on the other hand , a serum albumin level of 3.5 g / dl or less ( p < 0.01 ) , platelet count 10 10/l or less ( p = 0.04 ) , child - pugh class b ( p < 0.01 ) , and being positive for hepatitis c antibodies ( p < 0.05 ) were correlated with significantly worse recurrence - free survival ( table 2 ) . in pathological and tumor - related factors ,
multiple progressed hccs ( p < 0.01 ) were correlated with significantly worse recurrence - free survival by univariate analysis ( table 3 ) . according to multivariate analysis for factors that could influence overall survival , a platelet count 10 10/l or less ( hr 4.41 , 95% ci 2.049.52 , p < 0.01 ) and dcp value more than 40 mau / ml ( hr 3.55 , 95% ci 1.727.34 , p < 0.01 ) were selected as independent predictors of adverse overall survival of patients with hcc after hepatic resection ( table 4 ) . on the other hand ,
preoperative eob - mri ( hr 0.56 , 95% ci 0.360.86 , p < 0.01 ) and multiple progressed hccs ( hr 2.10 , 95% ci 1.293.40 , p < 0.01 ) were identified as independent factors significantly correlated with recurrence - free survival after hepatic resection ( table 4 ) .
the findings of this retrospective study showed that preoperative eob - mri and simultaneous treatment of ehcc prolonged recurrence - free survival but not overall survival of progressed hcc patients following hepatic resection .
univariate and multivariate analyses showed that preoperative eob - mri was one of the independent factors significantly correlated with recurrence - free survival after hepatic resection . to the best of our knowledge ,
this is the first study to show that simultaneous treatment of ehcc based on the preoperative imaging study including eob - mri prolonged recurrence - free survival after hepatic resection for hcc .
a new mr imaging contrast medium , gadoxetic acid , or gd - eob - dtpa , which has the properties of both an extracellular gadolinium chelate and liver - specific contrast material , has become available .
injection of a bolus of gd - eob - dtpa allows for the assessment of tumor vascularity using arterial phase imaging and enables hepatocyte - phase imaging approximately 20 minutes after its administration , with approximately 50% of the contrast material being taken up by hepatocytes [ 1013 ] .
eob - mri including a gradient dual - echo sequence and diffusion - weighted imaging has been recommended for the pretherapeutic evaluation of patients with hcc .
our previous study showed that eob - mri was the most useful imaging technique for evaluating small hcc , including ehcc .
hypovascular nodules that appear hypointense on hepatocyte - phase eob - mri may progress to conventional hypervascular hepatocellular carcinoma .
we previously showed that nodules more than 10 mm in diameter and containing fat were at a higher risk of developing hypervascularization .
moreover , a maximum diameter more than 10 mm or 15 mm or greater , increased growth rate , hyperintensity on t1-weighted images , hyperintensity on t2-weighted images , and a tumor volume doubling time of less than 542 days were reported to be risk factors of hypervascularization in hypovascular nodules that appeared hypointense on hepatocyte - phase eob - mri .
we showed that preoperative eob - mri and simultaneous treatment of ehcc at the time of resection for progressed hcc prolonged recurrence - free survival after hepatic resection .
the recurrence - free survival curves of the two groups overlapped within one year after hepatic resection and after that the incidence of recurrence in the eob - mri ( + ) group became significantly lower than that in the eob - mri ( ) group .
we speculate that recurrence within one year of hepatic resection is mainly due to enlargement of preoperatively undetectable intrahepatic micro i m of resected progressed hcc , while recurrence after one year was mc that progressed from ehcc to hypervascular hcc or was de novo hypervascular hcc .
we estimate that simultaneous treatment of ehcc at the time of resection for progressed hcc reduced mc by removing ehcc that may have progressed to hypervascular hcc .
one of the reasons why preoperative eob - mri and simultaneous treatment of ehcc at the time of resection prolonged recurrence - free survival but not overall survival after hepatic resection for hcc was early diagnosis and prompt treatment of recurrent hcc detected by our postoperative close follow - up . reducing postoperative recurrence after hepatic resection of hcc may not only diminish the burden on patients , but also preserve liver function .
the present study showed for the first time that preoperative eob - mri and simultaneous treatment of ehcc prolonged recurrence - free survival of progressed hcc patients following hepatic resection .
however , because our data were based on a retrospective study and limited number of patients , further prospective studies are required to fully evaluate the significance of preoperative eob - mri and simultaneous treatment of ehcc . | background / purpose .
the purpose of this study was to clarify whether preoperative gadoxetic acid - enhanced magnetic resonance imaging ( eob - mri ) and simultaneous treatment of suspected early hepatocellular carcinoma ( ehcc ) at the time of resection for progressed hcc affected patient prognosis following hepatic resection . methods .
a total of 147 consecutive patients who underwent their first curative hepatic resection for progressed hcc were enrolled . of these
, 77 patients underwent eob - mri ( eob - mri ( + ) ) before hepatic resection and the remaining 70 patients did not ( eob - mri ( ) ) .
suspected ehccs detected by preoperative imaging were resected or ablated at the time of resection for progressed hcc .
results .
the number of patients who underwent treatment for ehccs was significantly higher in the eob - mri ( + ) than in the eob - mri ( ) ( 17 versus 6 ; p = 0.04 ) .
recurrence - free survival ( 1- , 3- , and 5-year ; 81.4 , 62.6 , 48.7% versus 82.1 , 41.5 , 25.5% , resp . , p < 0.01 ) , but not overall survival ( 1- , 3- , and 5-year ; 98.7 , 90.7 , 80.8% versus 97.0 , 86.3 , 72.4% , resp . ,
p = 0.38 ) , was significantly better in the eob - mri ( + ) .
univariate and multivariate analyses showed that preoperative eob - mri was one of the independent factors significantly correlated with better recurrence - free survival .
conclusions .
preoperative eob - mri and simultaneous treatment of ehcc prolonged recurrence - free survival after hepatic resection . |
health - care professionals are accustomed to seeing frail older persons , but rarely do they recognize the role of sarcopenia in the pathogenesis of frailty .
even more rarely do they institute an aggressive treatment regimen to improve the older person s quality of life .
for this reason , six societies , including the scwd , published a consensus statement that defined frailty as a medical syndrome with multiple causes and contributors that is characterized by diminished strength , endurance and reduced physiologic function that increases an individual s vulnerability for developing increased dependency and/or death .
for this reason , they agreed that all persons older than 70 years and all individuals with significant weight loss ( 5 % ) due to chronic disease , should be screened for frailty .
an objective definition for a physical frailty phenotype was created and validated in 2001 by fried et al . .
their definition included weight loss , exhaustion , weakness ( grip strength ) , walking speed , and low physical activity .
they found that it was present in approximately 7 % of persons in the cardiovascular health study .
based on this schema , a simple five - point questionnaire was developed by the international association of nutrition and aging ( table 1 ) .
this consists of adding together all the deficits a person has and then mathematically designating a frailty score .
while this is highly predictive of poor outcomes , it is more of a comorbid score than a physical frailty index .
it has also been recognized that persons with psychosocial frailty as well as physical frailty tend to have even worse outcomes [ 510].table 1the simple frail scale
fatigue
resistance ( can you climb a flight of stairs ? )
aerobic ( can you walk a block ? )
illness ( > 5 )
loss of weight ( 5 % in 6 months)three or more positive answers , frail ; one or two positive answers , prefrail the simple frail scale three or more positive answers , frail ; one or two positive answers , prefrail the frail ( fatigue , resistance , aerobic , illness , and loss of weight ) scale has been validated by six separate studies and appears to perform as well as the other more complex scales [ 1116 ] . of the five components of the frail scale , both resistance ( climb a flight of stairs ) and aerobic ( walk one block ) are clearly components of sarcopenia as now defined by multiple groups [ 1721 ] .
in addition , while there are many causes of fatigue ( e.g. , anemia , endocrine disorders , sleep apnea , polypharmacy , depression , and vitamin b12 deficiency ) , it is now well recognized that a major cause of fatigue in conditions such as heart failure is poor muscle function [ 22 , 23 ] .
while weight loss is not universal in sarcopenia , loss of muscle can lead to weight loss in persons who do not develop obese sarcopenia , and it is a hallmark of cachexia [ 25 , 26 ] .
the frailty consensus statement recommended that the treatments for frailty should be exercise ( resistance and aerobic ) , protein - calorie supplementation , vitamin d , and reduction of polypharmacy .
the evidence that exercise ( particularly resistance exercise ) when maintained can have marked effects on frailty and sarcopenia is now very strong [ 2833 ] .
the major problem is that this form of exercise therapy needs to be provided in a long term , i.e. , for at least a year , where it performs better than conventional physical therapy .
it is the time that health - care agencies fund coaches to do twice weekly home visits to do resistance exercise for a year or longer .
there is increasing evidence for exercise to be coupled with high quality protein to provide optimal muscle performance [ 3539 ] .
persons with low vitamin d have been demonstrated to have decreased strength and increased falls [ 40 , 41 ] .
replacement of vitamin d in these persons appears to improve strength and decrease hip fractures .
calorie replacement decreases mortality and possibly improves function in persons with malnutrition . for an optimal effect
in addition to these basic treatments , there is an increasing interest in developing drugs to treat sarcopenia .
testosterone has been demonstrated to increase muscle mass and strength in older persons with and without frailty [ 4651 ] .
its possible side effects have led to enthusiasm to produce selective androgen receptor molecules , and one of these , enobosarm , has shown some promise .
a variety of other drugs are in earlier stages of development for treating sarcopenia and cachexia .
frailty can be screened for by general practitioners as demonstrated by the gerontopole frailty screening tool [ 54 , 55 ] .
a simple screening tool , the frail , takes less than 15 s to do and does not require a physician to administer it . treatments for frailty clearly exist . for these reasons
we suggest that it is time to couple sarcopenia and frailty and increase its community awareness .
if physicians begin to recognize sarcopenia and physical frailty and utilize the simple management strategies available , they will begin to have revealed to them the wonders of watching frail , and sarcopenic persons become more functional and happier in a way similar to how each few steps in a hidden garden reveals yet another wonder . | the physical frailty phenotype consists of fatigue , weight loss , and loss of muscle power .
sarcopenia has been shown to be a major cause of frailty .
six societies including scwd published a consensus suggesting that all persons older than 70 years of age should be screened for frailty when seeing health professionals .
simple screening tests such as the frail ( fatigue , resistance , aerobic , illness , and loss of weight ) scale can be used .
it is felt that frailty can be treated by exercise ( resistance and aerobic ) , high quality protein , vitamin d , and treatment of the common causes of fatigue .
it is expected that this approach will decrease disability in older persons . |
mical directs the organization of actin in a number of different cell types including within developing bristle processes , which are akin to mammalian mechanotransducing inner ear hair cells that detect sound .
bristles have also long served as a simple , single cell model for characterizing actin dependent events in vivo . raising the levels of mical specifically in bristle cells using the gal4-uas system ( bristle - specific gal4/uas : mical ) results in f - actin disassembly and bristle branching ( compare figure 1a and b ) that is dependent on mical 's redox activity and the met-44 residue of actin .
thus , to better characterize mical - mediated f - actin alterations , we have initiated a large - scale genetic screen to look for enhancers and suppressors of mical - mediated bristle branching .
one of the mutations that we identified in our genetic screen , the transposable element mutation ey22443 , strongly suppressed mical - induced actin - dependent bristle branching ( figure 1b - d ) .
molecular analysis revealed that the ey22443 transposable element mutation was situated within the drosophila selr gene ( figure 1e ) .
selr codes for a methionine sulfoxide reductase ( msrb ) family enzyme , that has been characterized for its ability to reduce oxidized methionine residues . in light of our observations that mical oxidizes methionine residues on actin , we wondered if selr might play a role in modulating mical 's effects on actin . the ey22443 transposable element mutation situated in selr contains a uas promoter ( figure 1e ) , thereby suggesting that this mutation might be abnormally inducing selr expression to suppress gal4/uas : mical - dependent bristle branching . to test this hypothesis
consistent with our results with ey22443 ( figure 1c - d ) and another uas - containing mutation within selr , ep3340 ( figure 1d ) , multiple transgenic lines revealed that raising the levels of selr specifically in bristles strongly suppressed mical - induced bristle branching and even generated normal appearing bristles ( figure 1f ) .
moreover , elevating the levels of selr in a wild - type background generated abnormally bent bristles that resembled mical mutant bristles ( figure s1 ; ) ; and these effects of selr were genetically enhanced by decreasing the levels of mical ( figure s1 ) .
further analysis revealed that selr localized with mical at the tips of bristles and suppressed mical - mediated f - actin disassembly and reorganization ( figure 1f ) .
therefore , selr counteracts the effects of mical on actin reorganization in vivo . to better understand the role of selr in counteracting mical - mediated actin reorganization
, we purified recombinant drosophila selr protein ( figure s2 ) . using in vitro actin biochemical and imaging assays
, we previously observed that purified mical protein in the presence of its coenzyme nadph disrupts actin polymerization and induces f - actin disassembly ( figure 2a ; ) .
strikingly , we found that purified selr protein rescued the ability of mical - treated actin to polymerize ( figure 2a ) .
this mical / selr - treated actin re - polymerized to an extent that was indistinguishable from normal untreated actin ( figure 2b ) .
moreover , while mical - treated actin failed to polymerize even after removal of mical and nadph ( figure 2c ; ) , selr induced the polymerization of this purified mical - treated actin in a dosage - dependent manner ( figure 2c ) .
selr converts methionine sulfoxide ( meto ) to methionine , requiring a redox active cysteine ( cys124 ) residue ( figure 2d - e ; ) and also utilizing reducing agents to cycle back to its reduced form ( figures 2d , s3 ; ) . in some cases methionine oxidation is also reversed by general reducing agents , so we wondered if mical - treated actin was specifically reversed by selr .
in contrast to selr , neither chemical reducing agents such as dtt ( figures 2a [ buffer only contains dtt ] ; s3 ) nor other reducing enzymes including thioredoxins / thioredoxin reductases altered mical - mediated effects on actin in vitro ( figure s3 ) or in vivo ( figure 1d ) .
furthermore , selr did not restore the normal polymerization properties of other oxidized forms of actin ( e.g. , h2o2-treated actin ; figure s3 ) , indicating that selr selectively affects mical- modified actin .
mutating selr 's critical catalytic cysteine ( cys124 ) to generate an enzymatically dead selr ( selr ; figure 2e ; ) , abolished selr 's effects on mical - treated actin in vitro ( figures 2b , f ) and in vivo ( figure 2 g ) .
moreover , consistent with such a role for selr 's reductase activity in counteracting mical 's oxidative effects on actin , elevating the levels of wild - type selr not only phenocopied the in vivo effects of disrupting mical 's monooxygenase ( redox ) domain ( figures s1 , s4 ) , but it also rescued the severe bristle / f - actin alterations that result from hyperactive mical redox signaling ( figure s4 ; mical ; ) .
thus , selr specifically employs its catalytic activity to restore mical - treated actin polymerization and counteract the in vivo effects of mical . in many organisms , including drosophila and mammals , two main types of methionine sulfoxide reductases have been identified : selr ( msrb family proteins ) and drosophila eip71cd ( msra ) ( figure 3a ; ) .
interestingly , selr and msra / eip71cd are both methionine sulfoxide reductases , but they do not exhibit similarity in their sequence , domain organization , or substrate specificity ( figure 3a - b ;
) . in particular , methionine has a unique oxidation pattern in that two stereoisomers can be produced by oxidation .
selr / msrb family proteins catalyze the reduction of the r - isomer of methionine sulfoxide ( methionine - r - sulfoxide ; figure 3b , top ) to methionine , while msra / eip71cd catalyzes the reduction of the s - isomer of methionine sulfoxide ( methionine - s - sulfoxide ; figure 3b , bottom ) to methionine .
therefore , to further test the specificity of selr in restoring the polymerization properties of mical - treated actin , we purified recombinant msra / eip71cd protein ( figure s2 ; ) .
unlike selr , msra / eip71cd did not restore the polymerization properties of mical - treated actin in vitro ( figure 3c ) , nor did it counteract mical - mediated actin reorganization / bristle branching in vivo ( figure 1d ) .
these results further reveal that mical - treated actin polymerization is specifically restored by selr .
moreover , in light of the isomer - specific nature of the methionine sulfoxide enzymes selr and msra / eip71cd , these results also indicate that mical oxidizes actin in a stereo - specific manner .
mical oxidizes actin on its met-44 and met-47 residues , although it is the oxidation of the met-44 residue through which mical induces f - actin disassembly .
previously , we determined the conditions to purify mical - treated actin , which is polymerization impaired and exhibits a mass increase of two oxygens ( 32 daltons ) .
selr , but not the enzymatically dead selr protein , restored the polymerization properties of purified mical - treated actin ( figure s3 ) , an effect that was maintained even after removal of selr ( figure 3d ) . subjecting both purified mical / selr - treated and mical / selr - treated actin to mass spectrometry revealed that selr , but not the enzymatically dead selr protein , eliminated the mical - catalyzed two oxygen ( 32 dalton ) mass increase on actin ( figure 3e ) .
mical 's ability to effect actin in vitro and in vivo is dependent on the presence of the methionine ( m ) 44 residue of actin .
to further examine a physiological role for selr in reducing mical - mediated oxidation of met-44 , we turned to in vivo assays .
we first noted that overexpression of either a non - mical oxidizable met44leu ( m44l ) version of actin or wild - type selr generated the same effects : suppression of mical - mediated actin / bristle morphology and mical loss - of - function - like defects ( figures 1f , 2 g , s1 , s4 ; ) .
furthermore , we found that actin worked in combination with selr to generate mical loss - of - function - like bristle defects ( figure s4 ) .
moreover , actin prevented the enhanced mical - mediated bristle branching / actin reorganization that occured with expression of the reductase dead selr ( figure 2 g ) .
thus , selr reverses mical - mediated oxidation of actin , including using its catalytic activity to directly reduce mical - induced meto-44 actin to met-44 actin ( figure 3f ) and these observations with purified proteins are supported by our in vivo genetic assays . in addition to bristle cells , mical regulates the organization of actin in multiple other cell types including mammalian cells in vitro and muscles in vivo .
thus , we wondered if selr could also counteract the effects of mical on actin in these other cellular systems .
our initial examination revealed that as in bristle cells , selr rescued mical - dependent changes in morphology and actin organization in cultured cells ( figure 4a ) .
further examination revealed that overexpression of selr in muscles in vivo phenocopied the muscle actin defects found in mical mutants ( figure 4b ; ) .
moreover , selr could even rescue the lethality and changes in actin organization associated with overexpression of mical in muscles ( figure 4c ) as well as the lethality that results when mical is broadly expressed using an actin promoter ( figure 4c ) .
drosophila selr , like mical , is broadly expressed ( figure s5 ; ) and thus to better examine these mical - selr interactions and their physiological effects on actin , we characterized selr mutants ( figure s6 ) . strikingly , loss of selr generated bristle and muscle defects that resembled overexpression of mical ( figure 5a and 5e ) . moreover ,
loss of selr specifically enhanced mical - mediated effects on actin organization / bristle morphology ( figures 5b - c , s4 ) and phenocopied overexpression of the selr reductase mutant protein ( figure 5d ) .
thus , selr , like mical , plays both important and selective roles in regulating actin organization in vivo in different cell types .
likewise , an equilibrium between mical and selr activities underlies normal actin - directed cell biology .
besides its redox region that mical uses to oxidize actin , mical has several other domains and protein interaction motifs including a region that interacts with the cytoplasmic portion of plexin ( figure 6a ; ) .
plexins are receptors for semaphorin guidance cues and play critical roles in regulating multiple actin - dependent events in vivo .
semaphorins / plexins signal through mical to induce changes in bristle morphology and f - actin disassembly , so we wondered if selr also counteracted the effects of semaphorin / plexin / mical signaling . employing loss and gain - of - function genetics in the bristle system , we found that similar to our results with mical , selr counteracted semaphorin / plexin effects on actin - dependent bristle morphology ( figure s1 ) . next , we turned to in vivo axon guidance assays , where semaphorins / plexins have been characterized as repulsive axon guidance molecules and were first linked to mical family proteins .
interestingly , one of the selr mutants that we found in our screen ( ep3340 , figure 1d - e ) recently emerged from a genetic screen as an uncharacterized regulator of axon guidance . employing our selr transgenic lines , we found that overexpression of selr generated axon guidance and synaptogenic defects that phenocopy mical mutants ( figures 6b , s6 ; ) .
furthermore , selr mutants generated axon guidance defects that phenocopy increased semaphorin / plexin / mical - mediated repulsive axon guidance ( figures 6c , s6 ; ) .
moreover , increasing the levels of selr rescued these semaphorin / plexin / mical - triggered repulsive axon guidance defects ( figures 6d , s6 ) .
thus , selr also plays critical roles in axon guidance and synaptogenesis and counteracts the effects of semaphorin / plexin / mical repulsive signaling in vivo .
mical directs the organization of actin in a number of different cell types including within developing bristle processes , which are akin to mammalian mechanotransducing inner ear hair cells that detect sound .
bristles have also long served as a simple , single cell model for characterizing actin dependent events in vivo . raising the levels of mical specifically in bristle cells using the gal4-uas system ( bristle - specific gal4/uas : mical ) results in f - actin disassembly and bristle branching ( compare figure 1a and b ) that is dependent on mical 's redox activity and the met-44 residue of actin .
thus , to better characterize mical - mediated f - actin alterations , we have initiated a large - scale genetic screen to look for enhancers and suppressors of mical - mediated bristle branching .
one of the mutations that we identified in our genetic screen , the transposable element mutation ey22443 , strongly suppressed mical - induced actin - dependent bristle branching ( figure 1b - d ) .
molecular analysis revealed that the ey22443 transposable element mutation was situated within the drosophila selr gene ( figure 1e ) .
selr codes for a methionine sulfoxide reductase ( msrb ) family enzyme , that has been characterized for its ability to reduce oxidized methionine residues . in light of our observations that mical oxidizes methionine residues on actin , we wondered if selr might play a role in modulating mical 's effects on actin . the ey22443 transposable element mutation situated in selr contains a uas promoter ( figure 1e ) , thereby suggesting that this mutation might be abnormally inducing selr expression to suppress gal4/uas : mical - dependent bristle branching . to test this hypothesis
consistent with our results with ey22443 ( figure 1c - d ) and another uas - containing mutation within selr , ep3340 ( figure 1d ) , multiple transgenic lines revealed that raising the levels of selr specifically in bristles strongly suppressed mical - induced bristle branching and even generated normal appearing bristles ( figure 1f ) .
moreover , elevating the levels of selr in a wild - type background generated abnormally bent bristles that resembled mical mutant bristles ( figure s1 ; ) ; and these effects of selr were genetically enhanced by decreasing the levels of mical ( figure s1 ) .
further analysis revealed that selr localized with mical at the tips of bristles and suppressed mical - mediated f - actin disassembly and reorganization ( figure 1f ) .
to better understand the role of selr in counteracting mical - mediated actin reorganization , we purified recombinant drosophila selr protein ( figure s2 ) . using in vitro actin biochemical and imaging assays , we previously observed that purified mical protein in the presence of its coenzyme nadph disrupts actin polymerization and induces f - actin disassembly ( figure 2a ; ) .
strikingly , we found that purified selr protein rescued the ability of mical - treated actin to polymerize ( figure 2a ) .
this mical / selr - treated actin re - polymerized to an extent that was indistinguishable from normal untreated actin ( figure 2b ) .
moreover , while mical - treated actin failed to polymerize even after removal of mical and nadph ( figure 2c ; ) , selr induced the polymerization of this purified mical - treated actin in a dosage - dependent manner ( figure 2c ) .
selr converts methionine sulfoxide ( meto ) to methionine , requiring a redox active cysteine ( cys124 ) residue ( figure 2d - e ; ) and also utilizing reducing agents to cycle back to its reduced form ( figures 2d , s3 ; ) . in some cases
methionine oxidation is also reversed by general reducing agents , so we wondered if mical - treated actin was specifically reversed by selr .
in contrast to selr , neither chemical reducing agents such as dtt ( figures 2a [ buffer only contains dtt ] ; s3 ) nor other reducing enzymes including thioredoxins / thioredoxin reductases altered mical - mediated effects on actin in vitro ( figure s3 ) or in vivo ( figure 1d ) . furthermore , selr did not restore the normal polymerization properties of other oxidized forms of actin ( e.g. , h2o2-treated actin ; figure s3 ) , indicating that selr selectively affects mical- modified actin .
mutating selr 's critical catalytic cysteine ( cys124 ) to generate an enzymatically dead selr ( selr ; figure 2e ; ) , abolished selr 's effects on mical - treated actin in vitro ( figures 2b , f ) and in vivo ( figure 2 g ) .
moreover , consistent with such a role for selr 's reductase activity in counteracting mical 's oxidative effects on actin , elevating the levels of wild - type selr not only phenocopied the in vivo effects of disrupting mical 's monooxygenase ( redox ) domain ( figures s1 , s4 ) , but it also rescued the severe bristle / f - actin alterations that result from hyperactive mical redox signaling ( figure s4 ; mical ; ) .
thus , selr specifically employs its catalytic activity to restore mical - treated actin polymerization and counteract the in vivo effects of mical .
in many organisms , including drosophila and mammals , two main types of methionine sulfoxide reductases have been identified : selr ( msrb family proteins ) and drosophila eip71cd ( msra ) ( figure 3a ; ) .
interestingly , selr and msra / eip71cd are both methionine sulfoxide reductases , but they do not exhibit similarity in their sequence , domain organization , or substrate specificity ( figure 3a - b ;
) . in particular , methionine has a unique oxidation pattern in that two stereoisomers can be produced by oxidation .
selr / msrb family proteins catalyze the reduction of the r - isomer of methionine sulfoxide ( methionine - r - sulfoxide ; figure 3b , top ) to methionine , while msra / eip71cd catalyzes the reduction of the s - isomer of methionine sulfoxide ( methionine - s - sulfoxide ; figure 3b , bottom ) to methionine . therefore , to further test the specificity of selr in restoring the polymerization properties of mical - treated actin , we purified recombinant msra / eip71cd protein ( figure s2 ; ) .
unlike selr , msra / eip71cd did not restore the polymerization properties of mical - treated actin in vitro ( figure 3c ) , nor did it counteract mical - mediated actin reorganization / bristle branching in vivo ( figure 1d ) .
these results further reveal that mical - treated actin polymerization is specifically restored by selr .
moreover , in light of the isomer - specific nature of the methionine sulfoxide enzymes selr and msra / eip71cd , these results also indicate that mical oxidizes actin in a stereo - specific manner .
mical oxidizes actin on its met-44 and met-47 residues , although it is the oxidation of the met-44 residue through which mical induces f - actin disassembly .
previously , we determined the conditions to purify mical - treated actin , which is polymerization impaired and exhibits a mass increase of two oxygens ( 32 daltons ) .
selr , but not the enzymatically dead selr protein , restored the polymerization properties of purified mical - treated actin ( figure s3 ) , an effect that was maintained even after removal of selr ( figure 3d ) . subjecting
both purified mical / selr - treated and mical / selr - treated actin to mass spectrometry revealed that selr , but not the enzymatically dead selr protein , eliminated the mical - catalyzed two oxygen ( 32 dalton ) mass increase on actin ( figure 3e ) .
mical 's ability to effect actin in vitro and in vivo is dependent on the presence of the methionine ( m ) 44 residue of actin .
to further examine a physiological role for selr in reducing mical - mediated oxidation of met-44 , we turned to in vivo assays .
we first noted that overexpression of either a non - mical oxidizable met44leu ( m44l ) version of actin or wild - type selr generated the same effects : suppression of mical - mediated actin / bristle morphology and mical loss - of - function - like defects ( figures 1f , 2 g , s1 , s4 ; ) .
furthermore , we found that actin worked in combination with selr to generate mical loss - of - function - like bristle defects ( figure s4 ) .
moreover , actin prevented the enhanced mical - mediated bristle branching / actin reorganization that occured with expression of the reductase dead selr ( figure 2 g ) .
thus , selr reverses mical - mediated oxidation of actin , including using its catalytic activity to directly reduce mical - induced meto-44 actin to met-44 actin ( figure 3f ) and these observations with purified proteins are supported by our in vivo genetic assays .
in addition to bristle cells , mical regulates the organization of actin in multiple other cell types including mammalian cells in vitro and muscles in vivo .
thus , we wondered if selr could also counteract the effects of mical on actin in these other cellular systems .
our initial examination revealed that as in bristle cells , selr rescued mical - dependent changes in morphology and actin organization in cultured cells ( figure 4a ) .
further examination revealed that overexpression of selr in muscles in vivo phenocopied the muscle actin defects found in mical mutants ( figure 4b ; ) .
moreover , selr could even rescue the lethality and changes in actin organization associated with overexpression of mical in muscles ( figure 4c ) as well as the lethality that results when mical is broadly expressed using an actin promoter ( figure 4c ) .
drosophila selr , like mical , is broadly expressed ( figure s5 ; ) and thus to better examine these mical - selr interactions and their physiological effects on actin , we characterized selr mutants ( figure s6 ) . strikingly , loss of selr generated bristle and muscle defects that resembled overexpression of mical ( figure 5a and 5e ) . moreover ,
loss of selr specifically enhanced mical - mediated effects on actin organization / bristle morphology ( figures 5b - c , s4 ) and phenocopied overexpression of the selr reductase mutant protein ( figure 5d ) .
thus , selr , like mical , plays both important and selective roles in regulating actin organization in vivo in different cell types .
likewise , an equilibrium between mical and selr activities underlies normal actin - directed cell biology .
besides its redox region that mical uses to oxidize actin , mical has several other domains and protein interaction motifs including a region that interacts with the cytoplasmic portion of plexin ( figure 6a ; ) .
plexins are receptors for semaphorin guidance cues and play critical roles in regulating multiple actin - dependent events in vivo .
semaphorins / plexins signal through mical to induce changes in bristle morphology and f - actin disassembly , so we wondered if selr also counteracted the effects of semaphorin / plexin / mical signaling . employing loss and gain - of - function genetics in the bristle system
, we found that similar to our results with mical , selr counteracted semaphorin / plexin effects on actin - dependent bristle morphology ( figure s1 ) .
next , we turned to in vivo axon guidance assays , where semaphorins / plexins have been characterized as repulsive axon guidance molecules and were first linked to mical family proteins .
interestingly , one of the selr mutants that we found in our screen ( ep3340 , figure 1d - e ) recently emerged from a genetic screen as an uncharacterized regulator of axon guidance . employing our selr transgenic lines , we found that overexpression of selr generated axon guidance and synaptogenic defects that phenocopy mical mutants ( figures 6b , s6 ; ) .
furthermore , selr mutants generated axon guidance defects that phenocopy increased semaphorin / plexin / mical - mediated repulsive axon guidance ( figures 6c , s6 ; ) .
moreover , increasing the levels of selr rescued these semaphorin / plexin / mical - triggered repulsive axon guidance defects ( figures 6d , s6 ) .
thus , selr also plays critical roles in axon guidance and synaptogenesis and counteracts the effects of semaphorin / plexin / mical repulsive signaling in vivo .
our results reveal that mical - mediated actin alterations a selective means to post - translationally regulate f - actin dynamics and cellular behaviors are reversible .
this micalcatalyzed reaction is directly reversed by a specific methionine sulfoxide reductase enzyme , selr / msrb , which we also find selectively controls actin - dependent cellular events in vivo and regulates specific neuronal , muscular , and mechanosensory developmental processes .
we also find that selr counteracts semaphorins , which are one of the largest families of extracellular guidance cues and play a critical role in the formation and function of multiple tissues .
thus , our results demonstrate an important role for these methionine sulfoxide reductases enzymes thought to function primarily in the repair of oxidatively damaged methionine residues in modulating normal signaling events .
moreover , our genetic data , which reveals that selr and mical loss and gain - of - function phenotypes are opposite in appearance , indicate that selr has a specific , primary , and regulated role in counteracting mical during development .
the mical substrate met-44 residue of actin is conserved in all actin family members from yeast to humans and a dominant ( hetereozygous ) mutation in the met-44 residue ( m44 t ) of skeletal muscle actin underlies a human musculoskeletal disease associated with actin accumulation and aggregation ( nemaline myopathy ) .
this met-44 mutant version of human skeletal muscle actin would be predicted to prevent mical from having effects on skeletal muscle actin and generally phenocopies both mical mutants and selr muscle overexpression .
however , the met-44 residue is well - conserved and is at a subunit interface in filaments and thus mutating it may influence f - actin organization for reasons other than that it is non oxidizable .
it should be noted however , that our previous results indicate that met-44 mutant actin ( m44l ) appears to polymerize normally in vitro and in vivo , but is resistant to mical - mediated f - actin disassembly .
it is also interesting to note the differences in the cellular localization we see between selr and different forms of mical .
for example , in bristles , selr shows overlapping localization with mical , but is more broadly distributed than full - length mical , which strongly localizes to bristle tips ( figure 1f ; ) . the broader cellular localization of selr is similar to that seen when the hyperactive mical is expressed in bristles and other cells ( figure 4a ; ) . one of the differences between full - length mical and the hyperactive mical is the presence of the plexin - interacting region ( figure 6a ; ) .
our results indicate that full - length mical is susceptible to regulation by plexin , whereas the mical protein ( which does not have the plexin - interacting region ) is not regulated by plexin ( see also ) .
interestingly , the micals express multiple different transcripts , including versions that may be similar to mical .
thus , there may be roles for both endogenous sema / plexin - regulated and perhaps , non sema / plexin - regulated forms of mical ( which appear to be more generally localized in cells ) . in any case , it should be noted that we find that selr rescues both the lethality and f - actin defects associated with overexpression of either full - length mical or mical .
our results herein , coupled with our previous observations , also indicate that unlike diffusible oxidants that induce random protein modifications , mical - mediated oxidation is substrate , residue , and stereo - specific .
our results indicate that mical oxidizes the methioinine-44 residue of actin stereospecifically to generate actin methionine-44-r - sulfoxide ( actin ) to alter f - actin dynamics .
these observations contend that the enzyme - driven interconversion of specific met / met(r)o residues , similar to the reversible phosphorylation of specific serine , threonine , and tyrosine residues , provides a selective means to precisely modulate protein function .
moreover , in contrast to a view that oxidation simply plays a destructive role in cell health and protein function , our results indicate that the site specific and reversible oxidation of proteins is critical for proper cellular physiology .
thus , together , our results uncover a specific reversible redox cellular signaling system that dynamically regulates multiple actin cytoskeletal - mediated events and controls semaphorin / plexin repulsion .
| actin 's polymerization properties are dramatically altered by oxidation of its conserved methionine ( met)-44 residue . mediating
this effect is a specific oxidation - reduction ( redox ) enzyme , mical , that works with semaphorin repulsive guidance cues and selectively oxidizes met-44 .
we now find that this actin regulatory process is reversible .
employing a genetic approach , we identified a specific methionine sulfoxide reductase enzyme selr that opposes mical redox activity and semaphorin / plexin repulsion to direct multiple actin - dependent cellular behaviors in vivo .
selr specifically catalyzes the reduction of the r - isomer of methionine sulfoxide ( methionine - r - sulfoxide ) to methionine , and we found that selr directly reduced mical - oxidized actin , restoring its normal polymerization properties .
these results indicate that mical oxidizes actin stereo - specifically to generate actin met-44-r - sulfoxide ( actinmet(r)o-44 ) and they also implicate the interconversion of specific met / met(r)o residues as a precise means to modulate protein function . our results therefore uncover a specific reversible redox actin regulatory system that controls cell and developmental biology . |
various events can lead to burned skeletal remains , which may include transport accidents such as aircraft and rail ; suicides ; and terrorist attacks .
conventional methods of identification such as visual identification and fingerprints have been rendered redundant in cases where the body is burnt beyond recognition .
teeth and bones have the good fortune of surviving really high temperatures . teeth and the restorative material used as cavity fillings have an astonishing ability to resist extreme conditions of heat and cold .
this quality can be attributed to the protection offered from the surrounding orofacial structures such as the buccal mucosa and the labial mucosa .
studying the effect of heat on teeth and the restorations would help ascertain the temperature reached by the fire , if an accelerator was used and whether the blaze was the cause of death or the victim was dead prior to the fire .
additional information obtained from the available restorative material after a fire enhances the possibility of a positive identification .
the aim of this study was to find out the effect of heat on the teeth and the different restorations and their resistance to this extreme state .
apart from gross examination of the teeth , a stereomicroscopic study was carried out to study the finer details post exposure to fire .
eighty sound teeth , extracted for periodontal or orthodontic reasons were disinfected in a 5% sodium hypochlorite solution for 2 h and stored in sodium chloride 0.9% solution at room temperature for up to 1 month , and they were randomly divided into different groups .
group 1 : 20 unrestored teeth group ii : 20 amalgam restored teeth group iii : 20 glass ionomer restored teeth group iv : 20 zinc oxide eugenol restored teeth .
after restoration all samples were stored in a 0.9% sodium chloride solution at room temperature for 1 month before further tests . each specimen was placed in a custom made tray made of dental investment material and the samples were then exposed to direct heat in an oven at four different temperatures viz ; 200c , 400c , 600c , and 800c , with an increment rate of 30c / min . the number of samples and controls exposed to each target temperature is reported .
as soon as each target temperature was reached , the samples were removed from the oven and allowed to cool to room temperature .
the effects of high temperatures on teeth were overtly observed for the change of color and the intactness of the restorations . the macroscopic and stereomicroscopic findings for both restored as well as un - restored teeth were as follows : 200c : the color of the crown and root changed from yellowish white to light brown .
[ figure 1 ] stereomicroscope showed the appearance of micro cracks or fractures on the root .
unrestored tooth at 200c : macroscopically evident change of color , tending to yellow , brown , of both the root and the crown 400c : the color of the root had changed to steel gray or black while that of the crown remained light brown .
stereomicroscope showed extension of the micro fractures from the root or appearance of new ones on the surface of the crown as well .
600c : the crown had shattered into pieces while the root was intact , and black in color .
[ figure 2 ] stereo microscopic view showed numerous minute micro fractures on the root surface .
unrestored tooth at 600c : macroscopic evaluation showed black discoloration of the whole tooth , a shattered part of the crown and detachment of the enamel 800c : a drastic change in color of the root was seen , which turned to opaque white .
200c : the crown showed slight retraction of the amalgam filling from the light brown to black colored crown .
400c : the findings were similar to those at 200c with further retraction of the amalgam filling and loss of marginal seal seen with the stereomicroscope [ figures 3 and 4 ] .
amalgam restoration at 400c : macroscopically fillings were in place , although both showed the same phenomenon noted at 200c , that is the presence of bubbles on the surface amalgam restoration at 400c : retraction of the amalgam filling and loss of marginal seal seen with the stereomicroscope 600c : the tooth was shattered , but the filling was intact .
stereomicroscopic view showed fractures on the filling though the shape of the filling was maintained .
800c : the filling remained in place with an intact shape on the portion of the crown that was left . exposed portion of
200c : the color of the root had turned dark brown whereas the color of the filling showed areas that had turned light brown .
400c : the color of the crown was light brown whereas the root was turned to dark grey to charcoal black as did the color of the filling .
portions of the filling had broken off , and loss of marginal seal was observed .
600c : the crown was carbonized and completely shattered into pieces , but the outline of the filling was noticeable .
the cross - section of the filling shows no change in the color [ figure 5 ] .
stereo microscopically the color of the root had turned to dark brown to black and showed deep fracture lines .
zinc oxide eugenol at 600 : macroscopically dark gray with cracks and dimensional contraction by loss of water , agglomerated particles of zinc 800c : the filling was lost as the crown was shattered completely and root was intact . exposed dentin showed a bluish grey hue .
stereomicroscopic view showed minute fracture lines on the root , which had turned to opaque white .
200c : the restoration had extruded from the crown , which showed a slight change in color to light brown .
400c : the filling showed a change in color to light brown as was the color of the crown .
600c : loss of superficial portion of the crown structure was seen along with a portion of the filling .
glass ionomer restoration at 600c : stereomicroscope showed deep fracture lines along the length 800c : only a portion of the crown structure along with the filling remained .
the filling remained intact within the crown , which had turned opaque white as had the root [ figure 7 ] .
glass ionomer restoration at 800c : macroscopically only a portion of the crown structure along with the filling remained .
the filling remained intact within the crown which had turned opaque white as had the root
200c : the color of the crown and root changed from yellowish white to light brown .
[ figure 1 ] stereomicroscope showed the appearance of micro cracks or fractures on the root .
unrestored tooth at 200c : macroscopically evident change of color , tending to yellow , brown , of both the root and the crown 400c : the color of the root had changed to steel gray or black while that of the crown remained light brown .
stereomicroscope showed extension of the micro fractures from the root or appearance of new ones on the surface of the crown as well .
600c : the crown had shattered into pieces while the root was intact , and black in color .
[ figure 2 ] stereo microscopic view showed numerous minute micro fractures on the root surface .
unrestored tooth at 600c : macroscopic evaluation showed black discoloration of the whole tooth , a shattered part of the crown and detachment of the enamel 800c : a drastic change in color of the root was seen , which turned to opaque white .
200c : the crown showed slight retraction of the amalgam filling from the light brown to black colored crown .
400c : the findings were similar to those at 200c with further retraction of the amalgam filling and loss of marginal seal seen with the stereomicroscope [ figures 3 and 4 ] .
amalgam restoration at 400c : macroscopically fillings were in place , although both showed the same phenomenon noted at 200c , that is the presence of bubbles on the surface amalgam restoration at 400c : retraction of the amalgam filling and loss of marginal seal seen with the stereomicroscope 600c : the tooth was shattered , but the filling was intact .
stereomicroscopic view showed fractures on the filling though the shape of the filling was maintained .
800c : the filling remained in place with an intact shape on the portion of the crown that was left .
200c : the crown showed slight retraction of the amalgam filling from the light brown to black colored crown .
400c : the findings were similar to those at 200c with further retraction of the amalgam filling and loss of marginal seal seen with the stereomicroscope [ figures 3 and 4 ] .
amalgam restoration at 400c : macroscopically fillings were in place , although both showed the same phenomenon noted at 200c , that is the presence of bubbles on the surface amalgam restoration at 400c : retraction of the amalgam filling and loss of marginal seal seen with the stereomicroscope 600c : the tooth was shattered , but the filling was intact .
stereomicroscopic view showed fractures on the filling though the shape of the filling was maintained .
800c : the filling remained in place with an intact shape on the portion of the crown that was left .
200c : the color of the root had turned dark brown whereas the color of the filling showed areas that had turned light brown .
400c : the color of the crown was light brown whereas the root was turned to dark grey to charcoal black as did the color of the filling .
portions of the filling had broken off , and loss of marginal seal was observed .
600c : the crown was carbonized and completely shattered into pieces , but the outline of the filling was noticeable .
the cross - section of the filling shows no change in the color [ figure 5 ] .
stereo microscopically the color of the root had turned to dark brown to black and showed deep fracture lines .
zinc oxide eugenol at 600 : macroscopically dark gray with cracks and dimensional contraction by loss of water , agglomerated particles of zinc 800c : the filling was lost as the crown was shattered completely and root was intact .
stereomicroscopic view showed minute fracture lines on the root , which had turned to opaque white .
200c : the restoration had extruded from the crown , which showed a slight change in color to light brown .
400c : the filling showed a change in color to light brown as was the color of the crown .
600c : loss of superficial portion of the crown structure was seen along with a portion of the filling .
glass ionomer restoration at 600c : stereomicroscope showed deep fracture lines along the length 800c : only a portion of the crown structure along with the filling remained .
the filling remained intact within the crown , which had turned opaque white as had the root [ figure 7 ] .
glass ionomer restoration at 800c : macroscopically only a portion of the crown structure along with the filling remained .
the filling remained intact within the crown which had turned opaque white as had the root
most of the microscopic studies of enamel showed structural changes at 800c , whereas dentin showed changes at a comparatively lower temperature of 600c .
these changes are the result of the physiochemical properties of the material and their nature . even with these changes , individual components like
the change in the color , hue of the restoration and their external appearance are the most commonly observed findings in an incinerated tooth .
teeth are amazingly resistant to heat if it is subjected to it gradually , but if heated severely the tooth may disintegrate ; else they may resist temperatures unto 1200c .
care must be exercised while handling the burnt teeth and methods to reinforce the singed remains must be carried out so as to prevent them from disintegration .
fragmentation is the most important complication of burned human remains . according to the gustafson ,
the greatest disparity in the effect of high temperatures on restorations is seen in amalgam fillings .
pink pigments due to copper oxides and a golden thread due to mercuric oxide vapors that were seen in other studies were absent in this study .
the difference in the composition of amalgam and an inconsistency in the percentages of mercury , silver , and copper found in amalgam available in different parts of the world may be responsible for this discrepancy .
the contraction of the restoration and loss of marginal seal was due to evaporation of mercury and loss of organic matrix .
the bubbles observed on the surface of the restoration were due to evaporation of mercury .
gold inlays are known to resemble amalgam fillings because of the deposited vapor of mercury on it .
phosphate linings are known to resist fire very well , and are usually found at the bottom of the cavity when the amalgam filling is dislodged .
this could not be verified in this study , since , the amalgam filling was intact and in its place even at a temperature as high as 800c .
the charred appearance of the tooth indicates sudden and quick carbonization of the tooth and its conversion into solid carbon as any biomaterial does on exposure to high temperatures .
the teeth used in this study were specifically restored post extraction ; hence , the time elapsed since the fillings were carried out and the teeth incinerated could not be considered . in real time , there may be a time gap between the restorations carried out on the teeth and the incineration of the body .
restored teeth appeared to show cracks and fissures at lower temperatures than un - restored teeth .
this may be due to the alteration in the structural integrity of the tooth during cavity preparation .
contrarily to amalgam , zinc oxide eugenol filling showed extrusion indicating expansion of the filling instead of marginal contraction .
in incinerated remains tooth colored fillings are the most difficult to identify macroscopically , but the use of a stereomicroscope simplifies the task .
the stereomicroscope can also be used to differentiate the gold fillings with amalgam residue on them from actual amalgam fillings and to detect the presence of a root canal filling after an explosion of the crown of the tooth .
teeth like bones have been known to react in a predictable manner when subjected to natural elements such as fire , earth , and water .
this study was performed on extracted teeth ; hence , exact results may not be obtained when a body is subjected to an intensive heat source .
the effects produced depend upon variables , such as the intensity of heat , protection of surrounding tissue , duration of exposure to the heat , presence of an accelerator , and the medium used to extinguish the fire
. absence of these variables may have caused an early evaporation of organic components with subsequent shattering or explosion of the crown around 800c .
thus , the teeth are known to survive higher temperatures than those mentioned in this study .
the effect of heat on teeth in reality is further complicated by the duration of exposure to high temperatures .
in this study , the teeth were subjected to a single , limited , and controlled exposure to heat .
we conclude that the possible temperature of exposure can be estimated by analyzing the changes in the teeth and their restorations , though , further studies on other materials used in the restoration of decayed or missing teeth such as acrylic , porcelain , and stainless steel are required . | background : in large scale disasters associated with fire the damage caused by heat can make medico legal identification of human remains difficult .
teeth , restorations , and prostheses all of which are resistant to quite high temperatures and can be used as aids in identification process.aim:aim of the study was to investigate the macroscopic and microscopic changes of teeth and several dental filling materials exposed to a range of high temperature ( 200 - 800c ) .
dental restorations include filling materials , crown , and bridges.materials and methods : restored and unrestored teeth were placed in a furnace and heated at a rate of 30c / min and the effects of the predetermined temperatures 200 , 400 , 600 , and 800c were observed .
macroscopic and stereo microscope findings were observed.results:our results showed that teeth and restorative materials resist higher temperatures than theoretically predicted and that even when a restoration is lost because of detachment or change of state , its ante - mortem presence can be confirmed and detected by stereo microscopic examination of the residual cavity.conclusion:we further conclude that a reasonably reliable estimation of the temperature of exposure can be made from an analysis of the teeth and restorative materials . |
in the last 30 years , massive resources have been deployed to understand the molecular components and processes of human cells , both for clinical and fundamental research applications .
while this effort has been first targeted toward the sequencing of the genome and the mapping of its transcriptome , it has now shifted toward the studies of the major actors of life , proteins .
the molecular and functional complexity of human proteins is challenging and requires bioinformatics resources specifically aimed at capturing , integrating and maintaining up - to - date the available knowledge about them . in a step toward this end
, the uniprot / swiss - prot group has completed the manual annotation of the full set of human proteins , derived from about 20 000 genes , in september 2008 ( 1 ) .
the proteomic space generated from these gene products is enormous , up to an estimated 1 million different protein species derived from dna recombination , alternative mrna splicing and the wealth of protein post - translational modifications ( ptms ) .
however , as estimated from the uniprotkb / swiss - prot knowledgebase content , 25% of those proteins ( i.e. around 5000 ) have not yet been studied experimentally . for the remainder ,
many proteins have not been completely analyzed with respect to their abundance , distribution , subcellular localization and interactions with other biomolecules , post - translational modifications or even more critical function .
the more complete our understanding of human proteins is the better equipped we will be to understand the functioning of the human body at molecular level .
much undiscovered knowledge is hidden in large sets of heterogeneous and noisy data distributed across a multitude of resources and web sites .
the problem is intensified by the fact that databases regularly become obsolete after a few years due to lack of financial support .
this trend is especially true for research on human biology , owing to the sheer quantity of resources at the disposal of researchers . to address these issues , we have created nextprot ( http://www.nextprot.org/ ) , a web - based protein knowledge platform on human proteins ( see screenshot of the home page in figure 1 ) .
the ultimate goal for nextprot is to serve for research on human the same role that model organism databases ( mods ) serve for model species .
nextprot is developed within the swiss institute of bioinformatics ( sib ) ( www.isb-sib.ch ) , which has extensive expertise in building high - quality protein - centric resources such as uniprotkb / swiss - prot ( 2 ) , prosite ( 3 ) , enzyme ( 4 ) , string ( 5 ) and the swiss - model repository ( 6 ) .
users can sign - in ( top right ) to create a personal account that allows them to personalize their usage of the platform by keeping a history of their queries and favoring or tagging search results .
the home page also links to pages with more information about the current content of the platform in term of integrated resources ( release details link at the bottom right ) .
users can sign - in ( top right ) to create a personal account that allows them to personalize their usage of the platform by keeping a history of their queries and favoring or tagging search results .
the home page also links to pages with more information about the current content of the platform in term of integrated resources ( release details link at the bottom right ) .
nextprot is being developed as a service for the community , and is using the knowledge and the expertise of the community to populate it with very high quality data and tools . for each data type
we need to incorporate , we identify groups that have expertise in that area and collaborate with them to integrate data .
in addition to making nextprot and its users benefit from expert data in all areas , this philosophy helps us ensure that our data are up to date and helps advertise both nextprot and our collaborators ' resources to our respective user communities via reciprocal cross - links . the primary data set in nextprot comes from the high - quality solid work that has been the hallmark of uniprotkb / swiss - prot since its inception in 1986 : we integrate all the information from the swiss - prot human entries .
the information captured by swiss - prot , however , is only a small fraction of what is available .
the fact that nextprot is centered on a single species , human , makes it possible to widen not only the quantity but also the range of data being captured . while we are still early in the nextprot development path , we have already integrated a significant amount of additional information relevant to human proteins , notably :
extensive protein expression information obtained by immunohistochemistry on healthy tissues from the human protein atlas ( hpa ) ( 7).micro - array and cdna expression information in healthy tissues originating from arrayexpress ( 8) and unigene ( 9,10 ) .
this rna - based expression data have been meta - analyzed by the sib evolutionary bioinformatics group and is available in the bgee resource ( 11).subcellular localization results from two different high - throughput projects : dkfz gfp - cdna localization ( 12,13 ) ; and weizmann institute of science 's kahn dynamic proteomics database ( 14).we have started to integrate high - quality mass spectrometry - derived proteomics information and , in particular , a number of published sets of n - glycosylation and phosphorylation sites . we also store peptide / protein identification results from experiments carried out in the context of the hupo plasma ( 15 ) and brain ( unpublished ) initiatives obtained from peptideatlas ( 16 ) , as well as some sets directly submitted to us by a network of collaborators.the gene ontology ( go ) ( 17,18 ) annotations of all human proteins as captured by goa ( 19).the mapping of proteins to their genomic transcripts on the human genome using ensembl ( 20).additional single - amino acid polymorphism ( saps ) variants obtained from dbsnp ( 9 ) and ensembl.additional identifiers , including cdna clone names encoding for the proteins , affymetrix and illumina dna probesets ; cross - references to ccds ( 21 ) and hprd ( 22).abstracts of all articles from pubmed that are cited in human swiss - prot entries as well as some cited by other resources such as entrez gene ( generifs ) ( 9 ) , mint ( 23 ) and pdb ( 24 ) and which have been computationally mapped to the relevant protein entry by the uniprot consortium .
extensive protein expression information obtained by immunohistochemistry on healthy tissues from the human protein atlas ( hpa ) ( 7 ) .
micro - array and cdna expression information in healthy tissues originating from arrayexpress ( 8) and unigene ( 9,10 ) .
this rna - based expression data have been meta - analyzed by the sib evolutionary bioinformatics group and is available in the bgee resource ( 11 ) .
subcellular localization results from two different high - throughput projects : dkfz gfp - cdna localization ( 12,13 ) ; and weizmann institute of science 's kahn dynamic proteomics database ( 14 ) .
we have started to integrate high - quality mass spectrometry - derived proteomics information and , in particular , a number of published sets of n - glycosylation and phosphorylation sites .
we also store peptide / protein identification results from experiments carried out in the context of the hupo plasma ( 15 ) and brain ( unpublished ) initiatives obtained from peptideatlas ( 16 ) , as well as some sets directly submitted to us by a network of collaborators .
the gene ontology ( go ) ( 17,18 ) annotations of all human proteins as captured by goa ( 19 ) .
the mapping of proteins to their genomic transcripts on the human genome using ensembl ( 20 ) .
additional single - amino acid polymorphism ( saps ) variants obtained from dbsnp ( 9 ) and ensembl .
additional identifiers , including cdna clone names encoding for the proteins , affymetrix and illumina dna probesets ; cross - references to ccds ( 21 ) and hprd ( 22 ) . abstracts of all articles from pubmed that are cited in human swiss - prot entries as well as some cited by other resources such as entrez gene ( generifs ) ( 9 ) , mint ( 23 ) and pdb ( 24 ) and which have been computationally mapped to the relevant protein entry by the uniprot consortium . ontologies and controlled vocabularies ( cvs ) are essential for consistent annotation and powerful data retrieval .
it is a challenge to choose the most appropriate vocabularies with respect to completeness , how well it represents the data we are capturing and how much interoperability it provides with other resources .
we have imported into nextprot the gene ontology ( go ) , uniprot disease , keyword , post - translational modification and subcellular location ontologies , unipathway ( 25 ) , enzyme classification ( enzyme ) and part of the medical subject headings ( mesh ) ( 26 ) .
we also created mini - cvs based on uniprotkb annotations to cater for domains , protein families , protein - bound metal ligands and topology .
available ontologies and controlled vocabularies , including mesh , evoc ( 27 ) , brenda tissue ontology ( 28 ) and fma ( 29 ) , describe human anatomy with different scopes , coverage and precision levels .
since none of them allowed us to integrate and compare data from different resources ( e.g. microarrays / ests from bgee and immunohistochemistry from hpa ) keeping the original granularity , we developed our own tissue and cell - type ontology .
users access the platform through an intuitive , simple interface centered on a google - like search functionality that enables both simple ( free text ) and relatively complex queries ( through the use of search topics ) ( figure 2 ) .
users can choose to search in nextprot for protein entries , publications or terminologies ( ontologies and controlled vocabularies ) .
once a search has been made , it is possible to filter the results according to a number of criteria .
the search results are displayed either as simple lists or as mini - summaries .
nextprot is indexed across several biological areas , corresponding to the different views found on each entry ( some data are present in multiple indexes ) .
this allows users to make complex searches , for example finding all proteins localized to the lysosomes and expressed in the brain . from the search results page , it is possible to do various exports :
obtain the list of proteins as an excel file ; the protein sequences as fasta or peff , or the entire entry in xml format . when a user is logged in
, checkboxes appear next to each entry , so that s / he is able to select specific entries for which the data are exported .
nextprot is indexed across several biological areas , corresponding to the different views found on each entry ( some data are present in multiple indexes ) .
this allows users to make complex searches , for example finding all proteins localized to the lysosomes and expressed in the brain . from the search results page ,
it is possible to do various exports : obtain the list of proteins as an excel file ; the protein sequences as fasta or peff , or the entire entry in xml format . when a user is logged in , checkboxes appear next to each entry , so that s / he is able to select specific entries for which the data are exported .
users of nextprot can sign - in to create a personal account that allows them to personalize their usage of the platform by keeping a history of their queries and favoring or tagging the search results .
nextprot provides an original way of visualizing proteins entries : they can be seen from three different perspectives : the
the protein and gene perspectives are further subdivided in views that put the available information in context : function , medical , expression ( figure 3 ) , interactions , localization , sequence ( figure 4 ) , proteomics , structures , exons ( figure 5 ) and protein and gene identifiers .
sequence view , the different splice isoforms can be graphically compared , highlighting the shared and specific sequence features ( domains , sites , etc . ) of each form .
figure 3.the expression data view displays data via a browser of the nextprot human anatomy ontology .
currently , the data presented come from two different sources : bgee and hpa ( see text ) .
data are captured and displayed at the original granularity level ( loupe symbols ) , and is propagated to higher levels using the ontology to be comparable across the data sets .
the tool provides a menu to toggle between showing only gold data and showing both gold and silver data .
figure 4.the sequence viewer , accessible from the sequence view , displays - in addition to the sequence itself , the different features of the sequence ( processing , regions , modified residues , topological information , variants , sequence conflicts , etc . ) as a graphical overview and a table view .
when a feature is selected , either from the graphical viewer or from the feature table , the corresponding sequence is immediately highlighted on the right .
the sequence viewer also provides direct access to the blast tool , which has the option of using the full sequence , a selection corresponding to a sequence feature or any other sub - sequence selected by the user .
figure 5.the exon view , available from the gene perspective , gives the precise coordinates of all protein isoforms that can be mapped on ensembl transcripts , based on exons .
for each exon , its position on the gene is shown , as well as the length if the exon in nucleotides .
the coding regions are represented by a small glyph , in which coding fragments are shown with a large green line , and non - coding sequences by a thin gray line .
the first and the last amino acid of each exon are shown , and the reading frame of each exon is indicated by red labeling of the amino acids . for example , val 96ile 110 means that the first amino acid of that exon ( val ) is completely encoded within that exon , while only the first nucleotide of the last one ( ile ) is encoded in that exon .
the expression data view displays data via a browser of the nextprot human anatomy ontology .
currently , the data presented come from two different sources : bgee and hpa ( see text ) .
data are captured and displayed at the original granularity level ( loupe symbols ) , and is propagated to higher levels using the ontology to be comparable across the data sets .
the tool provides a menu to toggle between showing only gold data and showing both gold and silver data .
the sequence viewer , accessible from the sequence view , displays - in addition to the sequence itself , the different features of the sequence ( processing , regions , modified residues , topological information , variants , sequence conflicts , etc . ) as a graphical overview and a table view . when a feature is selected , either from the graphical viewer or from the feature table , the corresponding sequence is immediately highlighted on the right .
the sequence viewer also provides direct access to the blast tool , which has the option of using the full sequence , a selection corresponding to a sequence feature or any other sub - sequence selected by the user .
the exon view , available from the gene perspective , gives the precise coordinates of all protein isoforms that can be mapped on ensembl transcripts , based on exons .
for each exon , its position on the gene is shown , as well as the length if the exon in nucleotides .
the coding regions are represented by a small glyph , in which coding fragments are shown with a large green line , and non - coding sequences by a thin gray line .
the first and the last amino acid of each exon are shown , and the reading frame of each exon is indicated by red labeling of the amino acids .
for example , val 96ile 110 means that the first amino acid of that exon ( val ) is completely encoded within that exon , while only the first nucleotide of the last one ( ile ) is encoded in that exon .
nextprot also provides a dedicated page for each term from our controlled vocabularies and ontologies .
these pages display graphical and tree representations of the ontologies , as well as links to proteins annotated with these terms or their children ( figure 6 ) .
similarly , there are pages for publications : these pages display the full publication record , including the abstract as well as the list of proteins that were annotated with that publication .
figure 6.for each term within the ontologies and hierarchical controlled vocabularies , a dedicated page shows its definition , synonyms and cross - references to other ontologies .
in addition , the graphical ontology viewer shows the relationship of that term to all its parents . for each term within the ontologies and hierarchical controlled vocabularies
, a dedicated page shows its definition , synonyms and cross - references to other ontologies .
in addition , the graphical ontology viewer shows the relationship of that term to all its parents . in term of tools
, nextprot provides access to a simple blast ( 30 ) implementation and we are currently beta - testing a tool to analyze enrichment of lists of proteins in term of various categories of annotations such as go terms , domains , subcellular locations , etc .
nextprot provides export functionality , namely , the download of lists of protein entries as text or excel files , the corresponding sequences in fasta format and the complete set of annotations in xml . to cater the needs of the proteomics community , we are the first resource to have implemented export of sequences and annotations of ptms and variants in the peff format ( 31 ) which has been developed in the context of the hupo proteomics standards initiative .
bulk download of the full complement of sequence and annotations is also available through our anonymous ftp site ( ftp.nextprot.org ) . through the ftp site
not all data published or available in public repositories are of the same quality . however
, this fact has rarely been captured in databases , whose attitude is often that the user should be able to view all data to make a judgment on the reliability of the information s / he is presented with .
this attitude tends to overwhelm the user with too much information , often making it simply impracticable to evaluate it ; and requires that all users have expertise in all fields . in an attempt to overcome this problem
, we are providing nextprot users with a data integration philosophy based on a three - tier quality system :
gold : highest quality data , corresponding to error rates of < 1%.silver : good quality data , corresponding to error rates of < 5% .
silver data are marked as such in the annotations.bronze : data deemed of a lower quality that we do not integrate in nextprot .
bronze : data deemed of a lower quality that we do not integrate in nextprot . within nextprot , users can choose to view and search only
gold data ( the default option ) , or view both gold and silver. the grading of experimental data is not a trivial process and there is no simple rule that can be applied across the large landscape of high - throughput technologies that produce the data that need to be integrated into nextprot . to make our quality - grading criteria transparent to users
, we are documenting these criteria in a metadata information record linked to the relevant experiments .
whenever possible , we establish the quality thresholds bronze , silver and gold with the group who has produced the data .
we expect that quality grading will be a dynamic process where users feedback will play an important role .
much undiscovered knowledge is hidden in large sets of heterogeneous and noisy data distributed across a multitude of resources and web sites .
the problem is intensified by the fact that databases regularly become obsolete after a few years due to lack of financial support .
this trend is especially true for research on human biology , owing to the sheer quantity of resources at the disposal of researchers . to address these issues , we have created nextprot ( http://www.nextprot.org/ ) , a web - based protein knowledge platform on human proteins ( see screenshot of the home page in figure 1 ) .
the ultimate goal for nextprot is to serve for research on human the same role that model organism databases ( mods ) serve for model species .
nextprot is developed within the swiss institute of bioinformatics ( sib ) ( www.isb-sib.ch ) , which has extensive expertise in building high - quality protein - centric resources such as uniprotkb / swiss - prot ( 2 ) , prosite ( 3 ) , enzyme ( 4 ) , string ( 5 ) and the swiss - model repository ( 6 ) .
users can sign - in ( top right ) to create a personal account that allows them to personalize their usage of the platform by keeping a history of their queries and favoring or tagging search results .
the home page also links to pages with more information about the current content of the platform in term of integrated resources ( release details link at the bottom right ) .
users can sign - in ( top right ) to create a personal account that allows them to personalize their usage of the platform by keeping a history of their queries and favoring or tagging search results .
the home page also links to pages with more information about the current content of the platform in term of integrated resources ( release details link at the bottom right ) .
nextprot is being developed as a service for the community , and is using the knowledge and the expertise of the community to populate it with very high quality data and tools . for each data type
we need to incorporate , we identify groups that have expertise in that area and collaborate with them to integrate data .
in addition to making nextprot and its users benefit from expert data in all areas , this philosophy helps us ensure that our data are up to date and helps advertise both nextprot and our collaborators ' resources to our respective user communities via reciprocal cross - links .
the primary data set in nextprot comes from the high - quality solid work that has been the hallmark of uniprotkb / swiss - prot since its inception in 1986 : we integrate all the information from the swiss - prot human entries .
the information captured by swiss - prot , however , is only a small fraction of what is available .
the fact that nextprot is centered on a single species , human , makes it possible to widen not only the quantity but also the range of data being captured . while we are still early in the nextprot development path , we have already integrated a significant amount of additional information relevant to human proteins , notably :
extensive protein expression information obtained by immunohistochemistry on healthy tissues from the human protein atlas ( hpa ) ( 7).micro - array and cdna expression information in healthy tissues originating from arrayexpress ( 8) and unigene ( 9,10 ) .
this rna - based expression data have been meta - analyzed by the sib evolutionary bioinformatics group and is available in the bgee resource ( 11).subcellular localization results from two different high - throughput projects : dkfz gfp - cdna localization ( 12,13 ) ; and weizmann institute of science 's kahn dynamic proteomics database ( 14).we have started to integrate high - quality mass spectrometry - derived proteomics information and , in particular , a number of published sets of n - glycosylation and phosphorylation sites . we also store peptide / protein identification results from experiments carried out in the context of the hupo plasma ( 15 ) and brain ( unpublished ) initiatives obtained from peptideatlas ( 16 ) , as well as some sets directly submitted to us by a network of collaborators.the gene ontology ( go ) ( 17,18 ) annotations of all human proteins as captured by goa ( 19).the mapping of proteins to their genomic transcripts on the human genome using ensembl ( 20).additional single - amino acid polymorphism ( saps ) variants obtained from dbsnp ( 9 ) and ensembl.additional identifiers , including cdna clone names encoding for the proteins , affymetrix and illumina dna probesets ; cross - references to ccds ( 21 ) and hprd ( 22).abstracts of all articles from pubmed that are cited in human swiss - prot entries as well as some cited by other resources such as entrez gene ( generifs ) ( 9 ) , mint ( 23 ) and pdb ( 24 ) and which have been computationally mapped to the relevant protein entry by the uniprot consortium .
extensive protein expression information obtained by immunohistochemistry on healthy tissues from the human protein atlas ( hpa ) ( 7 ) .
micro - array and cdna expression information in healthy tissues originating from arrayexpress ( 8) and unigene ( 9,10 ) .
this rna - based expression data have been meta - analyzed by the sib evolutionary bioinformatics group and is available in the bgee resource ( 11 ) .
subcellular localization results from two different high - throughput projects : dkfz gfp - cdna localization ( 12,13 ) ; and weizmann institute of science 's kahn dynamic proteomics database ( 14 ) .
we have started to integrate high - quality mass spectrometry - derived proteomics information and , in particular , a number of published sets of n - glycosylation and phosphorylation sites . we also store peptide / protein identification results from experiments carried out in the context of the hupo plasma ( 15 ) and brain ( unpublished ) initiatives obtained from peptideatlas ( 16 ) , as well as some sets directly submitted to us by a network of collaborators .
the gene ontology ( go ) ( 17,18 ) annotations of all human proteins as captured by goa ( 19 ) . the mapping of proteins to their genomic transcripts on the human genome using ensembl ( 20 ) .
additional single - amino acid polymorphism ( saps ) variants obtained from dbsnp ( 9 ) and ensembl . additional identifiers , including cdna clone names encoding for the proteins , affymetrix and illumina dna probesets ; cross - references to ccds ( 21 ) and hprd ( 22 ) . abstracts of all articles from pubmed that are cited in human swiss - prot entries as well as some cited by other resources such as entrez gene ( generifs ) ( 9 ) , mint ( 23 ) and pdb ( 24 ) and which have been computationally mapped to the relevant protein entry by the uniprot consortium . ontologies and controlled vocabularies ( cvs ) are essential for consistent annotation and powerful data retrieval .
it is a challenge to choose the most appropriate vocabularies with respect to completeness , how well it represents the data we are capturing and how much interoperability it provides with other resources .
we have imported into nextprot the gene ontology ( go ) , uniprot disease , keyword , post - translational modification and subcellular location ontologies , unipathway ( 25 ) , enzyme classification ( enzyme ) and part of the medical subject headings ( mesh ) ( 26 ) .
we also created mini - cvs based on uniprotkb annotations to cater for domains , protein families , protein - bound metal ligands and topology .
available ontologies and controlled vocabularies , including mesh , evoc ( 27 ) , brenda tissue ontology ( 28 ) and fma ( 29 ) , describe human anatomy with different scopes , coverage and precision levels .
since none of them allowed us to integrate and compare data from different resources ( e.g. microarrays / ests from bgee and immunohistochemistry from hpa ) keeping the original granularity , we developed our own tissue and cell - type ontology .
users access the platform through an intuitive , simple interface centered on a google - like search functionality that enables both simple ( free text ) and relatively complex queries ( through the use of search topics ) ( figure 2 ) .
users can choose to search in nextprot for protein entries , publications or terminologies ( ontologies and controlled vocabularies ) .
once a search has been made , it is possible to filter the results according to a number of criteria .
the search results are displayed either as simple lists or as mini - summaries .
nextprot is indexed across several biological areas , corresponding to the different views found on each entry ( some data are present in multiple indexes ) .
this allows users to make complex searches , for example finding all proteins localized to the lysosomes and expressed in the brain . from the search results page ,
it is possible to do various exports : obtain the list of proteins as an excel file ; the protein sequences as fasta or peff , or the entire entry in xml format . when a user is logged in ,
checkboxes appear next to each entry , so that s / he is able to select specific entries for which the data are exported .
nextprot is indexed across several biological areas , corresponding to the different views found on each entry ( some data are present in multiple indexes ) .
this allows users to make complex searches , for example finding all proteins localized to the lysosomes and expressed in the brain . from the search results page ,
it is possible to do various exports : obtain the list of proteins as an excel file ; the protein sequences as fasta or peff , or the entire entry in xml format . when a user is logged in , checkboxes appear next to each entry , so that s / he is able to select specific entries for which the data are exported
. users of nextprot can sign - in to create a personal account that allows them to personalize their usage of the platform by keeping a history of their queries and favoring or tagging the search results .
nextprot provides an original way of visualizing proteins entries : they can be seen from three different perspectives : the
the protein and gene perspectives are further subdivided in views that put the available information in context : function , medical , expression ( figure 3 ) , interactions , localization , sequence ( figure 4 ) , proteomics , structures , exons ( figure 5 ) and protein and gene identifiers .
for example , in the sequence view , the different splice isoforms can be graphically compared , highlighting the shared and specific sequence features ( domains , sites , etc . ) of each form .
figure 3.the expression data view displays data via a browser of the nextprot human anatomy ontology .
currently , the data presented come from two different sources : bgee and hpa ( see text ) .
data are captured and displayed at the original granularity level ( loupe symbols ) , and is propagated to higher levels using the ontology to be comparable across the data sets .
the tool provides a menu to toggle between showing only gold data and showing both gold and silver data .
figure 4.the sequence viewer , accessible from the sequence view , displays - in addition to the sequence itself , the different features of the sequence ( processing , regions , modified residues , topological information , variants , sequence conflicts , etc . ) as a graphical overview and a table view .
when a feature is selected , either from the graphical viewer or from the feature table , the corresponding sequence is immediately highlighted on the right .
the sequence viewer also provides direct access to the blast tool , which has the option of using the full sequence , a selection corresponding to a sequence feature or any other sub - sequence selected by the user .
figure 5.the exon view , available from the gene perspective , gives the precise coordinates of all protein isoforms that can be mapped on ensembl transcripts , based on exons . for each exon , its position on the gene is shown , as well as the length if the exon in nucleotides .
the coding regions are represented by a small glyph , in which coding fragments are shown with a large green line , and non - coding sequences by a thin gray line .
the first and the last amino acid of each exon are shown , and the reading frame of each exon is indicated by red labeling of the amino acids .
for example , val 96ile 110 means that the first amino acid of that exon ( val ) is completely encoded within that exon , while only the first nucleotide of the last one ( ile ) is encoded in that exon .
the expression data view displays data via a browser of the nextprot human anatomy ontology .
currently , the data presented come from two different sources : bgee and hpa ( see text ) . data are captured and displayed at the original granularity level ( loupe symbols ) , and is propagated to higher levels using the ontology to be comparable across the data sets .
the tool provides a menu to toggle between showing only gold data and showing both gold and silver data .
the sequence viewer , accessible from the sequence view , displays - in addition to the sequence itself , the different features of the sequence ( processing , regions , modified residues , topological information , variants , sequence conflicts , etc . ) as a graphical overview and a table view . when a feature is selected , either from the graphical viewer or from the feature table , the corresponding sequence is immediately highlighted on the right .
the sequence viewer also provides direct access to the blast tool , which has the option of using the full sequence , a selection corresponding to a sequence feature or any other sub - sequence selected by the user .
the exon view , available from the gene perspective , gives the precise coordinates of all protein isoforms that can be mapped on ensembl transcripts , based on exons .
for each exon , its position on the gene is shown , as well as the length if the exon in nucleotides .
the coding regions are represented by a small glyph , in which coding fragments are shown with a large green line , and non - coding sequences by a thin gray line .
the first and the last amino acid of each exon are shown , and the reading frame of each exon is indicated by red labeling of the amino acids .
for example , val 96ile 110 means that the first amino acid of that exon ( val ) is completely encoded within that exon , while only the first nucleotide of the last one ( ile ) is encoded in that exon .
nextprot also provides a dedicated page for each term from our controlled vocabularies and ontologies .
these pages display graphical and tree representations of the ontologies , as well as links to proteins annotated with these terms or their children ( figure 6 ) .
similarly , there are pages for publications : these pages display the full publication record , including the abstract as well as the list of proteins that were annotated with that publication .
figure 6.for each term within the ontologies and hierarchical controlled vocabularies , a dedicated page shows its definition , synonyms and cross - references to other ontologies .
in addition , the graphical ontology viewer shows the relationship of that term to all its parents .
for each term within the ontologies and hierarchical controlled vocabularies , a dedicated page shows its definition , synonyms and cross - references to other ontologies .
in addition , the graphical ontology viewer shows the relationship of that term to all its parents . in term of tools
, nextprot provides access to a simple blast ( 30 ) implementation and we are currently beta - testing a tool to analyze enrichment of lists of proteins in term of various categories of annotations such as go terms , domains , subcellular locations , etc .
nextprot provides export functionality , namely , the download of lists of protein entries as text or excel files , the corresponding sequences in fasta format and the complete set of annotations in xml . to cater the needs of the proteomics community , we are the first resource to have implemented export of sequences and annotations of ptms and variants in the peff format ( 31 ) which has been developed in the context of the hupo proteomics standards initiative .
bulk download of the full complement of sequence and annotations is also available through our anonymous ftp site ( ftp.nextprot.org ) . through the ftp site
however , this fact has rarely been captured in databases , whose attitude is often that the user should be able to view all data to make a judgment on the reliability of the information s / he is presented with .
this attitude tends to overwhelm the user with too much information , often making it simply impracticable to evaluate it ; and requires that all users have expertise in all fields . in an attempt to overcome this problem
, we are providing nextprot users with a data integration philosophy based on a three - tier quality system :
gold : highest quality data , corresponding to error rates of < 1%.silver : good quality data , corresponding to error rates of < 5% .
silver data are marked as such in the annotations.bronze : data deemed of a lower quality that we do not integrate in nextprot .
gold : highest quality data , corresponding to error rates of < 1% . silver : good quality data , corresponding to error rates of < 5% .
bronze : data deemed of a lower quality that we do not integrate in nextprot . within nextprot , users can choose to view and search only
gold data ( the default option ) , or view both gold and silver. the grading of experimental data is not a trivial process and there is no simple rule that can be applied across the large landscape of high - throughput technologies that produce the data that need to be integrated into nextprot . to make our quality - grading criteria transparent to users , we are documenting these criteria in a metadata information record linked to the relevant experiments .
whenever possible , we establish the quality thresholds bronze , silver and gold with the group who has produced the data .
we expect that quality grading will be a dynamic process where users feedback will play an important role .
nextprot aims to act as a central hub for all knowledge on human proteins . to achieve this
nextprot has been selected to be the knowledge platform for the newly launched hupo human proteome project ( hpp ) ( 32 ) . to this end , nextprot will need to integrate data and tools aimed to support the hpp . among other developments
, this means increasing the amount of proteomics data ( post - translational modifications and peptide identification ) and extending its scope toward quantification results obtained from selected reaction monitoring ( srm ) experiments .
we are collaborating with the string group ( http://string-db.org/ ) to integrate human protein network information ( 5 ) .
protein interaction data provided by intact ( 33 ) and other members of the imex consortium of interaction databases ( 34 ) , will allow nextprot users to explore graphically the functional protein complexes and their dynamic and spatial regulation through a cytoscape plugin ( 35 ) .
information on protein networks will be complemented by data on interactions between proteins and small molecules ( such as drugs ) and between proteins and nucleic acids .
while nextprot only caters for human proteins , we want to provide the phylogenetic range of species in which a given human protein exists .
we will also extract from swiss - prot experimental information carried out in organisms other than human but providing information directly relevant to the cognate human protein(s ) .
for example , selected phenotypes from knock out or knock down experiments in mouse or zebrafish or enzyme characterization of bovine or pig counterparts . in terms of tools and interface , we want to build an intuitive and powerful system , having capacities that are not yet available in other life sciences platforms .
this is why we want to add a number of tools to nextprot . among them
, we are planning to provide an advanced search option that will allow to specifically retrieve any stored data item and to carry out complex ( including boolean and analytical ) queries ; a multiple sequence aligner with a user - friendly interface and a 3d structure viewer that enables protein sequence annotations ( ptms , domains , variants , etc . ) to be displayed overlaid on the structural view .
we are also exploring how we can allow users who have created personal accounts to customize our platform and to allow them to participate in group discussions and data sharing activities .
currently , urls for searches and displayed pages are rest - compatible but this is not sufficient to allow third party developers to make full use of our platform and of the data available in nextprot .
this is why we are currently developing an application programming interface ( api ) for nextprot .
this api will be used to integrate the future 3d structure viewer developed by bionext ( http://www.bio-next.com ) in the context of a collaborative research project .
it extends the high - quality uniprotkb / swiss - prot annotations for human proteins to include several new data types .
the development of nextprot is just beginning and will continue to expand with respect to the quantity and scope of data presented .
we are convinced that the comprehensive biocuration of human proteins is a community endeavor . with this in mind
, nextprot is being built as a participative platform and we look forward to receiving users ' input for its future development .
the sib ; genebio sa ; the swiss confederation 's commission for technology and innovation ( cti , grant 10214.1 pfls - ls ) ; the nextprot server is hosted by vitalit ; the bioinformatics competence center that supports and collaborates with life scientists in switzerland . funding for open access charge : | nextprot ( http://www.nextprot.org/ ) is a new human protein - centric knowledge platform .
developed at the swiss institute of bioinformatics ( sib ) , it aims to help researchers answer questions relevant to human proteins . to achieve this goal ,
nextprot is built on a corpus containing both curated knowledge originating from the uniprotkb / swiss - prot knowledgebase and carefully selected and filtered high - throughput data pertinent to human proteins .
this article presents an overview of the database and the data integration process .
we also lay out the key future directions of nextprot that we consider the necessary steps to make nextprot the one - stop - shop for all research projects focusing on human proteins . |
coumarin ( 1,2-benzopyrone ) is structurally the least complex
member of a large class of compounds known as benzopyrones
.
the biological activities of coumarin and related
compounds are multiple and include antithrombotic activity
and antimicrobial properties .
in addition , coumarins have been shown to inhibit n - methyl - n - nitrosourea , aflatoxin b1 and
7,12-dimethylbenz(a)anthracene - induced mammary carcinogenesis in
rats [ 4 , 5 ] .
more recently , coumarin derivatives have been
evaluated in the treatment of human immunodeficiency virus , due to
their ability to inhibit human immunodeficiency virus integrase
[ 6 , 7 ] .
since the late 1980s , a number of in vitro and in vivo studies have investigated the possible use of coumarins in the treatment of cancer .
the in vitro effects of coumarins on the growth of renal cell carcinoma that derived cell
lines showed that coumarin and 7-hydroxycoumarin were potent cytotoxic and cytostatic agents .
several authors have
reported on the use of coumarin ( 1,2-benzopyrone ) , or its
metabolite 7-hydroxycoumarin , for the treatment of some human
carcinomas [ 1013 ] .
there are several reports indicating that some coumarin compounds , including coumarin and 7-hydroxycoumarin , inhibit cell growth of cell lines of various
types of cancer [ 1418 ] .
the coumarin derivatives have been the focus of our recent
research concerning the design of new cytotoxic agents .
it is well
known that many investigations have proved that binding of a drug
to a metalloelement enhances its activity and , in some cases , the
complex possesses even more healing properties than the parent
drug .
this has prompted us to investigate the metal binding
properties of several coumarin derivatives .
we have recently
reported the synthesis of lanthanide(iii ) complexes with some
coumarins and the study of their anticancer activity
[ 1929 ] .
in previous works [ 1929 ] , we investigated the coordination behavior of some 4-hydroxycoumarins with cerium(iii ) , lanthanum(iii ) , and neodymium(iii ) .
in the course of these studies , considering that lanthanides(iii ) have an interesting but
not well - known biological role in living organisms as trace
elements , we have investigated the coordination properties of a
series of other lanthanides(iii ) with coumarin derivatives .
thus , the aim of this work is to synthesize and characterize
complexes of samarium(iii ) , gadolinium(iii ) , and dysprosium(iii )
with coumarin-3-carboxylic acid ( see figure 1 ) and to
determine the antiproliferative effects of these complexes against
the chronic myeloid leukemia - derived k-562 .
the cell line is
characterized with a strong expression of bcr - abl fusion protein ( a constitutive nonreceptor tyrosine kinase ) which
determines the low responsiveness of these cells to proapoptotic
stimuli .
grade : sm(no3)3 6h2o , gd(no3)3 6h2o , and dy(no3)3 5h2o . coumarin-3-carboxylic acid ( figure 1 ) was used for the preparation of metal complexes as a ligand .
the complexes were synthesized by reaction of samarium(iii ) ,
gadolinium(iii ) , and dysprosium(iii ) salts and the ligand , in
amounts equal to metal : ligand molar ratio of 1 : 2 .
the synthesis
of the complexes was made in different ratios ( 1 : 1 , 1 : 2 , 1 : 3 )
but in all the cases the product was with the composition 1 : 2 .
the complexes were prepared by adding ethanol solutions of
ln(iii ) salts to ethanol solutions of the ligand .
the
reaction mixture was stirred with an electromagnetic stirrer at
25c for one hour . at the moment of mixing of the
solutions ,
the precipitates were
filtered , washed several times with water and ethanol , and dried
in a desiccator to constant weight .
the complexes were insoluble in water , methanol , and ethanol and
well soluble in dmso .
the carbon , hydrogen , and nitrogen contents of the compounds were
determined by elemental analysis .
the water content was determined
by metrohn herizall e55 karl fisher titrator and was confirmed by
tga .
ir spectra ( nujol ) were recorded on ir - spectrometer ftir-8101 m
shimadzu .
the raman spectra of the ligand and their new
ln(iii ) complexes were recorded with a dilor
microspectrometer ( horiba - jobin - yvon , model labram ) equipped with
a 1800 grooves / mm holographic grating .
the 514.5 nm line
of an argon ion laser ( spectra physics , model 2016 ) was used for
the probes excitation .
the spectra were collected in a
backscattering geometry with a confocal raman microscope equipped
with an olympus lmplanfl 50x objective and with a resolution of
2 cm .
the detection of raman signal was carried out
with a peltier - cooled ccd camera .
the antiproliferative effects of the tested lanthanide complexes
and of the corresponding nitrate salts were assessed on the
chronic myeloid leukemia - derived k-562 .
the cells were maintained
as suspension - type cultures in a controlled environment : rpmi 1640
medium ( sigma ) , with 10% heat inactivated fetal bovine serum
( sigma ) and 2 mm l - glutamine ( sigma ) , in a
incubator with humidified atmosphere and 5% carbon dioxide , at 37c . in order to keep the cells in log phase , cell
suspension was discarded 2 or 3 times per week and the cell
culture was refed with fresh rpmi-1640 aliquots .
briefly , exponentially growing cells were seeded in 96-well
microplates ( 100 l / well ) at a density of 1 10
cells per ml and after 24-hour incubation at 37c they were
exposed to various concentrations of the lanthanide complexes for
48 hours . for each concentration
after the incubation with the test compounds mtt solution
( 10 mg / ml in pbs ) was added ( 10 l / well ) .
the plates
were further incubated for 4 hours at 37c and the formazan
crystals formed were dissolved through addition of
100 l / well 5% solution of formic acid in 2-propanol
( merck ) .
the absorption of the samples was then measured using an
elisa reader ( uniscan titertec ) at wavelength of 580 nm .
the
blank solution consisted of 100 l rpmi 1640 medium
( sigma ) , 10 l mtt stock , and 100 l 5% formic
acid in 2-propanol .
the survival fractions were calculated as
percentage of the untreated control using the formula
( 1)sf % = atestacontrol100 ,
where atest is the average value for the
absorption at a given concentration and acontrol is the average absorption of the untreated control , respectively .
the stock solutions of the tested lanthanide complexes ( at
20 mm ) were freshly prepared in dmso , and thereafter
consequently diluted in rpmi-1640 medium , in order to achieve the
desired final concentrations . at the final dilutions obtained , the
concentration of dmso never exceeded 1% . the stock solutions
( 20 mm , in water ) of the nitrate salts of the lanthanides were
freshly prepared and following antibacterial filtration they were
accordingly diluted in rpmi-1640 medium .
data processing , generation of dose - response curves , and ic50
calculations were performed using microsoft excel and microcal
origin software for pc .
the
metal ions were determined after mineralization . the water content
in the complexes was determined by karl fisher analysis .
the data of the elemental analysis of the compounds obtained
serving as a basis for the determination of their empirical
formulas and the results of the karl fisher analysis are presented
in table 1 .
the mode of bonding of the ligand to samarium(iii ) ,
gadolinium(iii ) , and dysprosium(iii ) ions was elucidated by
recording the ir and raman spectra of the complexes as compared
with those of the free ligand .
the vibrational spectra of the
complexes showed new bands in comparison with these of the free
ligand which have been assigned to the rocking , waggling , and
metal - oxygen stretching vibrations .
depending on the orientation of the two donor groups ,
c = o and coo , different binding of the anion of coumarin-3-carboxylic acid ( cca ) is possible .
however , in most of the known lanathanide complexes , the metal - ligand interaction is mainly electrostatic by nature . to help further the
binding mode elucidation in the new sm(iii ) ,
gd(iii ) , and dy(iii ) complexes of hcca ,
detailed vibrational analysis was performed on the basis of
comparison of experimental vibrational spectra of hcca and its
sm(iii ) , gd(iii ) , and dy(iii ) complexes with
those theoretically predicted by us earlier as
well as with literature data about related compounds .
the data of
the experimental ft - ir and ft - raman spectra of hcca and its
sm(iii ) , gd(iii ) , and dy(iii ) complexes are
given in table 2 .
the ft - raman spectra of the ligand and its ln(iii ) complexes are presented in
figure 2 .
the broadband at 3176 cm in the ir spectrum of the ligand was assigned to the (oh ) vibrational mode .
this band was not detected in the spectra of the complexes , indicating that the deprotonated ligand form participates in the complexes .
the bands in the 30602920 cm region were assigned to (ch ) modes of hcca . in the ir spectra of sm(iii ) , gd(iii ) , and dy(iii ) complexes they remain almost unchanged .
the strong ir bands at 1746 cm and 1685 cm and the medium raman bands at 1729 , 1676 , and
1663 cm were assigned to (c = o ) modes of
the carboxylic and carbonylic groups , respectively .
the high ir
intensity of these bands retained in the spectra of sm(iii ) , gd(iii ) , and dy(iii ) complexes , the (c = o)carboxylic band was shifted to lower frequency ( 1703 cm , 1703 cm , 1705 cm for sm(iii ) , gd(iii ) , and dy(iii ) complexes , resp . ) , and the (c = o)carbonylic band showed also a position change ( 1672 cm , 1672 cm , 1674 cm for sm(iii ) , gd(iii ) , and dy(iii ) complexes , resp . ) . the same shift effects were observed in the
raman spectra of the complexes . in agreement with the literature data ,
the bands
observed in the 16501330 cm frequency range are due
to the (cc ) stretching vibrations of hcca coumarin ring .
the bands that are typical for the coumarin vibrations were
not shifted significantly in the spectra of sm(iii ) , gd(iii ) , and dy(iii ) complexes , which indicated that the ln(iii ) cations did not produce substantial polarization on the coumarin ring .
the strong ir ( at 1613 and 1569 cm ) and raman ( at 1608 and 1559 cm ) bands are attributed to the (c = c ) stretching vibrations of hcca coumarin fragment .
their positions and intensities are almost retained and the second band is split in
the complexes .
the bands at 1489 , 1453 , and 1374 cm
( ir ) and at 1483 , 1442 , and 1363 cm ( raman ) , which also are assigned to the (cc ) modes of hcca , show shifts in the ir and raman spectra of sm(iii ) , gd(iii ) , and dy(iii ) complexes and at the same time the intensity of these bands increases .
the induced polarization by ln(iii)cca interaction produces electron
density distribution in the conjugated coumarin ring and as a result the (cc ) frequencies change their positions and intensity .
the strong bands at 1228 cm ( ir spectrum of hcca ) and at 1216 cm ( raman spectrum of hcca ) and the medium one at 989 cm , in the ir spectrum of hcca , were assigned to the lactone (co ) modes , respectively . in the complexes ,
these modes were shifted to lower frequency . in agreement with ln(iii)ocarbonyl interaction , the induced polarization on cca leads to changes of the co lactone bond lengths as well as of their frequencies in a direction mentioned above .
the following bands , observed in the ir spectra of the
complexes , are assigned to the vibrational modes of the no3 group : 1263 cm ( sm complex ) , 1262 cm ( gd complex ) , 1262 cm ( dy complex ) for (no)bonded ; 1053 cm ( sm complex ) , 1049 cm ( gd complex ) , 1049 cm ( dy complex ) for (ono ) ; 786 cm ( sm complex ) , 791 cm ( gd complex ) , 781 cm ( dy complex ) for (ono ) ; and 725 cm ( sm complex ) , 725 cm ( gd complex ) , 713 cm ( dy complex ) for (ono ) . some of them also appear in the raman spectra of the complexes : 1040 cm ( sm complex ) , 1040 cm ( gd complex ) , 1043 cm ( dy complex ) for (ono ) ; 777 cm ( sm complex ) , 772 cm ( gd complex ) , 777 cm ( dy complex ) for (ono ) . because of the predominant electrostatic character of the lno bonding , the bands corresponding to the (lno ) modes have low intensities , they are coupled with other modes and hence , their assignment is unreliable . the doublet bands observed in the ir spectra of the complexes at 767 , 748 cm ( sm complex ) , 768 , 749 cm ( gd complex ) , 766 , 750 cm ( dy complex ) , the bands at 459 cm ( sm complex ) , 457 cm ( gd complex ) , 457 cm ( dy complex ) , and the bands at 449 cm for sm(iii ) , gd(iii ) , and dy(iii ) complexes were assigned to (lno)carboxylic and (lno)carbonylic modes , respectively .
on the basis of the above - detailed vibrational study we can
conclude that the metal - ligand bonding in ln(iii ) complexes
of coumarin-3-carboxylic acid appeared to be strongly ionic with
very small donor - acceptor character .
the vibrational study gave
evidence for bidentate coordination of cca to sm(iii ) , gd(iii ) , and dy(iii ) ions through the carbonylic oxygen and the carboxylic oxygen .
a survey of the h nmr spectral data reveals downfield chemical shifts of the protons in the ln(iii ) complexes spectra relative to the free ligand .
the resonances due to protons
of the ligand are considerably broadened and shifted indicating
complexation .
this peak is absent in the spectra of
the complexes due to the deprotonation of the carboxylic group . in
the c nmr spectra of the complexes ,
the largest upfield chemical shifts are observed for the carbon atoms which
are neighbors of the carboxylic and carbonylic oxygens and this
finding confirms their participation in ln(iii)cca interaction .
the solvent dmso was used for the nmr measurements because the solubility of the complexes in noncoordinating
solvents was too low .
dmso molecule could indeed bind to the metal and
give rise to equilibrium , fast on the nmr time scale ,
involving the dmso molecule as an additional ligand ,
because of the high coordination number of ln(iii ) . taking
into consideration the obtained data
, we can say the following .
the results of nmr spectra , discussed above , and the
results of the pharmacological activity , presented below , all made
in dmso , give us reason to suggest that in these conditions
( in the solution of dmso ) the complexes are present .
the
stability of the complexes is of great interest with respect to
their further pharmacological properties ( not cytotoxicity test )
and will be the subject of coming investigations which are in
progress .
our previous molecular electrostatic potential ( mep ) study on the
preferred reactive sites of cca in the gas phase and in solution revealed two regions suitable for electrophilic attack
and binding : between the deprotonated carboxylic and the
carbonylic oxygens and between the carboxylic oxygens
[ 31 , 32 ] . to suggest the binding mode of hcca , a detail theoretical and vibrational investigation based on raman , ftir , and dft / b3lyp / svp studies of hcca , its deprotonated form
( cca ) , kcca , and ln(cca)2(no3)(h2o ) species ,
two bidentate binding modes of cca to ln(iii ) were modeled : ( 1 ) through the deprotonated carboxylic and the carbonylic oxygens and ( 2 ) through both carboxylic oxygens . the vibrational analysis and
the electronic energy calculations pointed to the first binding as more probable . on the basis of
detailed dft study of the vibrational behavior of hcca , cca , kcca , and ln(cca)2(no3)(h2o ) species and comparison of the theoretical and experimental vibrational spectra
, it was established that cca is bidentate bound to ln(iii ) through the carboxylic and the carbonylic atoms .
as seen from the vibrational spectra , the no3 group is bidentate coordinated , the calculated and experimental no3 modes for the complexes were found at very similar wavenumbers , and the assignment of the
no3 vibrational modes is in good agreement with literature data [ 31 , 32 ] .
moreover , the metal - ligand binding mode of coumarin-3-carboxylic
acid ( hcca ) was recently explained by us through modeling
of the ln(iii)-coumarin-3-carboxylic acid structures , where
ln = la , ce , nd [ 31 , 32 ] . it was suggested that
coumarin-3-carboxylic acid binds to the ln(iii ) ions
through both oxygen atoms of the carboxylic and carbonylic groups
from the ligands and through the oxygen atoms of
no3 , and thus , the central ion ln(iii ) is six - coordinated .
the nbo analysis of the complexes suggests predominantly ionic character of the lncca bond with slight ligand - metal charge transfer [ 31 , 32 ] .
nevertheless , we have to take into consideration that the
coordination number 6 for these central metal ions indeed is too
low , but not impossible for lanthanide(iii ) ions
[ 1929 , 31 , 32 ] .
one plausible mode of coordination might involve also the water molecules , which is
typical for coordination compounds of lanthanides . on the bases of our experimental spectral data and our theoretical
density function calculations [ 31 , 32 ]
, we were able to suggest the most probable structure of these ln(iii ) complexes .
the preliminary pharmacological screening performed revealed that
all of the lanthanide complexes exerted antiproliferative effects
against the chronic myeloid leukemia - derived k-562 line in a
concentration - dependent matter , which enabled the construction of
concentration response curves as depicted on figures 3 , 4 , 5 , 6 , 7 , 8 and table 3 .
in contrast to the sm(iii ) and gd(iii ) complexes with coumarin-3-carboxylic acid , dy(cca)2(no3 ) h2o failed to induce 50%
inhibition of the cellular proliferation within the concentration range under investigation .
interestingly , the gd(iii ) and
dy(iii ) nitrates were
found to exert considerable antiprolferative effects ( figures
6 , 7 , 8) , superior to
those of the complexes thereof .
in contrast , despite the
considerable activity of the samarium complex , the corresponding
nitrate salt sm(no3)3 6h2o ( figure 6 ) caused only marginal inhibitory effects against k-562 ( figure 3 ) .
the results from this study demonstrate the antiprolferative
potential of three novel lanthanide coordination compounds of
coumarin-3-carboxylic acid derivatives , in line with our preceding
papers concerning the activity of lanthanide
( ce(iii ) , la(iii ) , and nd(iii ) ) coordination compounds with diverse coumarin ligands [ 1929 ] . in our hands , the samarium(iii ) complex of coumarin-3-carboxylic acid proved to be the most active antiproliferative agent among the novel complexes and thus it necessitates further more detailed pharmacological evaluation .
the complex formation proved to be
detrimental for the efficacy of gd(iii ) and dy(iii ) compounds as in both cases the nitrates exerted superior efficacy
versus the corresponding coordination compounds . | new complexes of samarium(iii ) , gadolinium(iii ) , and dysprosium(iii ) with coumarin-3-carboxylic acid ( hcca ) were prepared by the reaction of the ligand with respective metal nitrates in ethanol .
the structures of the final complexes were determined by means of physicochemical data , elemental analysis , ir and raman spectra . the metal - ligand binding mode in the new ln(iii ) complexes of coumarin-3-carboxylic acid
was elucidated .
the vibrational study gave evidence for bidentate coordination of
cca to ln(iii ) ions through the carbonylic oxygen and the carboxylic oxygen atoms .
the complexes were tested for antiproliferative activitiy on the chronic myeloid leukemia - derived k-562 , overexpressing the bcr - abl fusion protein .
cytotoxicity towards tumor cells was determined for a broad concentration range .
the samarium salt exerted a very weak antiproliferative effect on these cells .
this is in contrast to the lanthanide complexes , especially samarium complex , which exhibited potent antiproliferative activity .
the present study confirms our previous observations that the lanthanide complexes of coumarins exhibit antiproliferative activity towards k-562 cell line . |
late ureteric stricture or obstruction is not rare in kidney transplantation and occurs at a frequency of 2% to 7.5% in renal transplant recipients .
the use of percutaneous nephrostomy ( pcn ) and antegrade ureteric stent implantation to treat renal allograft stricture or obstruction seems to be safe and effective .
however , it is not always possible to pass a guidewire through a tight ureteric stricture when the caliber of the ureter is too small . in the present study , we introduced an alternative technique of cystoscopic extraction and external drainage for unsuccessful antegrade percutaneous ureteric stenting in cases of severe transplanted ureteral obstruction .
we performed a retrospective review of all patients with ureteric stricture after kidney transplantation who underwent pcn and antegrade ureteric stenting in two hospitals between april 2001 and june 2011 .
two hundred twenty - seven patients were treated during this interval and all patients had previously consented to the use of their medical records for research purposes .
obstruction was defined by the presence of both an increasing serum creatinine concentration and hydronephrosis on ultrasound in all patients . during the ureteric stenting in cases of transplanted ureteric stricture or obstruction after ureterovesical anastomosis , two alternative techniques were performed instead of the conventional technique in 227 patients as below : a cystoscopic extraction technique was preferred when the portion of the guidewire passing through the stricture into the bladder was too short for the catheter to traverse the stricture via the guidewire under c - arm fluoroscopy .
we covered the renal introducer sheath with a sterile drape and changed the patient 's position from the supine to the lithotomic position .
then the distal portion of the guidewire ( 0.035 in , terumo , tokyo , japan ) inserted from the renal sheath was captured by use of a grasper through a flexible cystoscope ( olympus co. , tokyo , japan ) with the cooperation of a urologist .
the guidewire was extracted smoothly until its distal portion was long enough to coil within the bladder .
coiling the guidewire can provide sufficient support for the catheter to follow . as described in a previous report , a 5-fr angiography catheter ( cobra angiographic catheter , terumo , tokyo , japan ; ruc advantage catheter , cook , bloomington , in , usa ) was used to pass through the pelvis and ureter until through the stricture to advance to the bladder .
after the guidewire was extracted , contrast agent was injected through the catheter to ensure the location of its distal tip .
a stiff guidewire ( 0.035 inch , terumo ) was inserted through the catheter and the distal portion was left coiled within the bladder . a balloon catheter ( admiral xtreme , invatec s.p.a .
roncadelle , italy ) for ureteroplasty was successfully inserted and placed centrally on the point of the stricture .
then the balloon catheter insufflated with a mixture of normal saline and contrast agent was inflated repeatedly until the balloon notch disappeared .
subsequently , the introducer sheath was extracted and a temporary double - j stent ( visiostar standard , bad aibling , germany ) with a diameter of 6 or 7 fr was inserted into the correct position with the proximal j within the renal pelvis and the distal j within the urinary bladder ( fig .
the external drainage technique was performed to rescue the inability to cross the severe obstruction . following the successful pcn
, we performed an exchange to insert a dwelling external drainage catheter ( terumo ) via a stiff guidewire , with its distal portion within the renal pelvis .
then , 10-ml urine was removed through the drainage catheter and 5-ml contrast agent was injected to ensure the location .
the drains were discontinued until we were ready to perform the subsequent balloon angioplasty and stent insertion ( fig .
preoperative investigations regarding postprocedure outcomes included renal function tests , urine culture , ultrasonography , and pyelography .
repeated attempts to pass the guidewire through the tight ureteric stricture were made with local anesthesia under fluoroscopic guidance .
the double - j stents were maintained for at least 8 weeks and were removed as the hydronephrosis progressively improved during serial ultrasonographic follow - up .
technical success was defined as good position of the ureteric stent with adequate internal drainage of urine with relief of hydronephrosis .
we performed a retrospective review of all patients with ureteric stricture after kidney transplantation who underwent pcn and antegrade ureteric stenting in two hospitals between april 2001 and june 2011 .
two hundred twenty - seven patients were treated during this interval and all patients had previously consented to the use of their medical records for research purposes .
obstruction was defined by the presence of both an increasing serum creatinine concentration and hydronephrosis on ultrasound in all patients .
during the ureteric stenting in cases of transplanted ureteric stricture or obstruction after ureterovesical anastomosis , two alternative techniques were performed instead of the conventional technique in 227 patients as below : a cystoscopic extraction technique was preferred when the portion of the guidewire passing through the stricture into the bladder was too short for the catheter to traverse the stricture via the guidewire under c - arm fluoroscopy .
we covered the renal introducer sheath with a sterile drape and changed the patient 's position from the supine to the lithotomic position .
then the distal portion of the guidewire ( 0.035 in , terumo , tokyo , japan ) inserted from the renal sheath was captured by use of a grasper through a flexible cystoscope ( olympus co. , tokyo , japan ) with the cooperation of a urologist .
the guidewire was extracted smoothly until its distal portion was long enough to coil within the bladder .
coiling the guidewire can provide sufficient support for the catheter to follow . as described in a previous report ,
a 5-fr angiography catheter ( cobra angiographic catheter , terumo , tokyo , japan ; ruc advantage catheter , cook , bloomington , in , usa ) was used to pass through the pelvis and ureter until through the stricture to advance to the bladder .
after the guidewire was extracted , contrast agent was injected through the catheter to ensure the location of its distal tip .
a stiff guidewire ( 0.035 inch , terumo ) was inserted through the catheter and the distal portion was left coiled within the bladder . a balloon catheter ( admiral xtreme , invatec s.p.a .
roncadelle , italy ) for ureteroplasty was successfully inserted and placed centrally on the point of the stricture .
then the balloon catheter insufflated with a mixture of normal saline and contrast agent was inflated repeatedly until the balloon notch disappeared .
subsequently , the introducer sheath was extracted and a temporary double - j stent ( visiostar standard , bad aibling , germany ) with a diameter of 6 or 7 fr was inserted into the correct position with the proximal j within the renal pelvis and the distal j within the urinary bladder ( fig .
1 ) . the external drainage technique was performed to rescue the inability to cross the severe obstruction .
following the successful pcn , we performed an exchange to insert a dwelling external drainage catheter ( terumo ) via a stiff guidewire , with its distal portion within the renal pelvis .
then , 10-ml urine was removed through the drainage catheter and 5-ml contrast agent was injected to ensure the location .
the drains were discontinued until we were ready to perform the subsequent balloon angioplasty and stent insertion ( fig .
preoperative investigations regarding postprocedure outcomes included renal function tests , urine culture , ultrasonography , and pyelography .
repeated attempts to pass the guidewire through the tight ureteric stricture were made with local anesthesia under fluoroscopic guidance .
the double - j stents were maintained for at least 8 weeks and were removed as the hydronephrosis progressively improved during serial ultrasonographic follow - up .
technical success was defined as good position of the ureteric stent with adequate internal drainage of urine with relief of hydronephrosis .
a total of 201 of 227 patients underwent successful conventional ureteric stenting procedure . the conventional procedure resulted in failure in 26 of 227 patients .
of the 26 patients , 16 patients ( male : female , 11:5 ; mean age , 37.2 years ) underwent successful stent insertion combined with the cystoscopic extraction technique .
ten patients ( male : female , 7:3 ; mean age , 39.5 years ) underwent successful stent insertion after external drainage ( mean time , 56.3 hours ) combined with the conventional or cystoscopic extraction technique . the mean serum creatinine before stenting was 42.9 mg / dl ( range , 32.7 to 54.1 mg / dl ) , which decreased to 10.3 mg / dl ( range , 8.7 to 11.8 mg / dl ) after stenting .
the complications of the procedure were lower abdominal pain in 22 patients and gross hematuria in 9 patients .
the results of routine blood tests showed no decrease in hemoglobin or red blood cell count .
all complications were relieved with medical care within 3 to 5 days after the procedure .
the double - j ureteric stents were removed 8 to 11 weeks after insertion . in all cases ,
the patients were free of urologic symptoms and signs during the 6-month follow - up after stent removal .
the favorable results and acceptance of antegrade pcn and balloon dilatation combined with ureteric stent insertion have been well documented in recent years . however , it can be most challenging for interventional radiologists or urologists to pass conventional guidewires through tight distal ureteric strictures . to successfully traverse the ureteric stricture ,
a variety of modifications and innovations have been proposed in the literature . keeling and lee described the use of microcatheters and microwires to traverse these tight ureteric strictures . in that case , a hockey stick catheter was advanced over the microcatheter / guidewire combination into the bladder . then a stiff guidewire was exchanged via the hockey catheter , followed by balloon dilation and stent implantation .
kim and park introduced the " pullthrough " technique . in their method , a goose neck snare was introduced through a 7-fr sheath that was inserted from the urethra . the distal tip of the stiff guidewire was captured and retrieved through the urethral introducer sheath .
then , both ends of the guidewire were secured tightly and the double - j stent was inserted .
reported that the reverse end of a 0.014-inch dasher steerable or similar guidewire could be used to pass a tight ureteric stricture , followed by cardiac angioplasty balloon dilation .
learning from their experience , we attempted to perform a cystoscopic extraction technique when the portion of the guidewire traversing the obstruction into the bladder was too short to provide enough support for the catheter to follow it .
the distal tip of the guidewire in the bladder was captured through a flexible cystoscope with the cooperation of a urologist and extracted smoothly until its distal portion coiled within the bladder .
the coiled guidewire can provide sufficient support for the following steps to be performed . the 16 patients
compared with the pull - through technique , the merit of the cystoscopic extraction technique is that fewer disposable interventional materials are consumed , which reduces the cost ; furthermore , extraction through the cystoscope is intuitive and clear .
all of the above techniques focused on a catheter or stent or microguidewire " traversing " the stricture .
however , in some cases , neither a hydrophilic - coated guidewire nor a microguidewire can traverse the tortuosity of the ureteric stricture because the stricture caliber is too small .
kamiyama et al . reported that severe preoperative hydronephrosis was a risk factor causing stent failure .
the donor age , the presence of delayed graft function , a stentless anastomotic technique , and more than two graft arteries all increase the risk of stenosis . these factors all produce deterioration in the distal ureteral vascularization .
ureteric stricture regions are not only with anatomic stricture , but also accompany edematous changes of the mucosa next to hydronephrosis and hydroureter .
ureteral edema can further decrease both the local arterial blood supply and venous drainage , which lead to the development of ureteral ischemia as well as narrowing .
edema of the mucosa makes it more difficult for the guidewire to pass through the stricture .
furthermore , edema may increase the possibility of causing a perforation in the ureter while the guidewire traverses the stricture .
therefore , we understood that edema can play an important role in difficulties passing through a ureteric stricture , and that decompression can relieve the edema of the mucosa .
in present study , the ultrasonography and intravenous urography showed that all 10 patients suffered with hydronephrosis and hydroureter .
depending on their circumstances , we performed repeat procedures in two steps . in the first step , we performed external drainage to treat stenosis partly caused by edema through decompression to improve the local blood supply and venous drainage .
we then used a hydrophilic - coated guidewire to traverse the tight stricture after the relief of mucosal edema around the stricture site , followed by balloon dilation and stent implantation .
also , in two cases , we performed a cystoscopic extraction technique owing to the portion of the guidewire passing the stricture into the bladder being too short .
we think a possible cause was residual mucosal edema and severe stricture . the limitations of the current study are that it was retrospective in nature , and the sample size was relatively small .
furthermore , owing to the small sample size , whether the cystoscopic extraction technique was performed could not be predicted .
it is known that transplanted ureteric strictures have a frequent recurrence and balloon dilatation is less effective than other techniques .
although we successfully performed stent implantation in all 26 cases , which showed an excellent long - term result , the surgical techniques of ureterovesical anastomosis should be retrospectively analyzed .
however , to the best of our knowledge , this study represents the first report of the technique of the combination of a flexible cystoscopic extraction and the use of internal double j stents to rescue unsuccessful antegrade stenting in cases of severe transplanted ureteric obstruction and the first observation of external drainage duration .
we believe that the technique of cystoscopic extraction and indwelling external drainage is secure and useful for traversing a severe transplanted ureteral obstruction following initial failed stent implantation . whether cystoscopic extraction or the external drainage technique is preferred depends on the ability of the guidewire to traverse the obstruction . | purposethe aim of this research was to evaluate the efficacy of the cystoscopic extraction and external drainage techniques for unsuccessful antegrade stenting in transplanted severe ureteral obstruction.materials and methodsa total of 26 patients with severe transplanted ureteral obstruction in whom the cystoscopic extraction technique and/or external drainage technique was performed were retrospectively evaluated .
after the severe obstruction was successfully traversed , balloon dilatation followed by double - j stent insertion was performed.resultsof the 26 patients ( male : female , 9:4 ; mean age , 38.1 years ) who underwent failed ureteral stenting with the conventional procedure , 16 patients underwent successful stenting with the cystoscopic extraction technique , and 10 patients underwent successful stenting following external drainage .
the mean serum creatinine of the 26 patients before stenting was 42.9 mg / dl ( range , 32.7 to 54.1 mg / dl ) , which decreased to 10.3 mg / dl ( range , 8.7 to 11.8 mg / dl ) after stenting .
the complications of the procedure were lower abdominal pain in 22 patients and gross hematuria in 9 patients .
all complications were relieved with medical care within 3 to 5 days after the procedure .
no major complications occurred.conclusionsthe cystoscopic extraction technique and external drainage technique are safe and useful for traversing a severe transplanted ureteral obstruction after a failed conventional procedure . |
according to the american cancer society , 61,560 new cases of kidney cancer ( including renal and pelvis ) will occur in the united states in 2015 .
the preoperative diagnosis and intraoperative management of renal tumors rely heavily on the histopathological evaluation of needle core biopsies ( ncb ) and frozen section analyses ( fsa ) , respectively .
ncb is used preoperatively to determine the nature of a lesion ( benign or malignant ) for appropriate treatment selection , such as conservative or minimally invasive procedures ( e.g. , ablation therapy or nephron - sparing surgery ) .
this is , especially beneficial for elderly patients with comorbidities or patients with contraindication for major surgery .
although histopathological evaluation of the tissue by ncb and/or fsa is the gold - standard technique , they have significant limitations .
ncb requires tissue processing that is , fixation , sectioning and staining of the tissue .
tissue processing is a time - consuming procedure and , therefore , can not provide a real - time evaluation of the tissue , which in turn impacts patient management .
for example , a patient who undergoes a ncb for the diagnosis of a renal mass may come back with a nondiagnostic result ( in 1025% of cases ) after waiting several days for the histopathology report .
this may necessitate a repeat biopsy procedure , increasing the risk of biopsy related complications , cost , and patient morbidity .
fsa suffers from freezing artifacts that may hinder diagnosis and/or margin assessment during nephron - sparing surgery , and fsa also requires waste of tissue that could be retained for ancillary studies and/or formalin - fixation and paraffin embedding .
therefore , there is a need for a real - time imaging tool that can rapidly evaluate ex vivo tissue at cellular resolution without any tissue processing to greatly improve the management of kidney tumors .
recently , some optical biopsy techniques such as optical coherence tomography ( oct ) , confocal microscopy , optical reflectance / raman spectroscopy , and multiphoton microscopy have been explored for the evaluation of renal carcinomas in both in vivo and ex vivo settings . however , all these techniques have their own limitations , and there exists still a need for novel imaging modalities to address this gap in the optimal management of small renal masses ( srms ) . full - field optical coherence tomography ( ffoct ) is one such promising optical imaging technique that relies on the principles of white light interference microscopy to generate high resolution images with relatively large field of view in fresh and formalin fixed tissues .
ffoct has been previously utilized to assess histological features of ex vivo nonkidney tissues . here
, for the first time , we explored the potential of ffoct for the rapid evaluation of ex vivo kidney tissue .
twenty - five adult subjects who were diagnosed with kidney tumor on clinical imaging and underwent nephrectomies ( partial or radical ) at our institution participated in this institutional review board approved the study .
the freshly excised nephrectomy specimens ( n = 25 ) received in surgical pathology were processed according to standard protocol .
one section each from the tumor and nonneoplastic kidney were collected fresh in buffered saline and brought to the ffoct microscope for imaging . following ffoct imaging , the specimens were placed in 10% buffered formalin and submitted for routine histopathological examination .
a commercial ffoct system was used ( light - ct scanner , lltech sas , paris , france ) .
it is a modified high - resolution ffoct system ( 1.5 m transverse and 0.8 m axial resolution ) .
this system uses a spatially and temporally incoherent light source of low power ( quartz - halogen schott kl 1500 compact , mainz , germany ) .
transverse en - face tomographic images of the samples are obtained by the combination of interferential images acquired by a cmos camera .
the microscope utilizes two matched 10x per 0.3 na water immersion objectives ( olympus america , center valley , pa ) , one to collect reflections and backscattering signals from the specimen and the other to collect reflection signal from a reference mirror .
full - field optical coherence tomography showing ( a ) schematic diagram of the optical pathway and ( b ) photograph of the system used the samples to be imaged were immersed in an isotonic solution of phosphate - buffered saline ( pbs ; 2.7 mm potassium chloride and 137 mm sodium chloride ; ph 7.5 ) and placed in a sample holder ( part of the light - ct system ) .
a silica cover - slip was placed on top of the sample , and the base of the holder was gently moved upward , to slightly flatten the sample .
a thick layer of silicone oil was applied on the silica cover - slip as the objective immersion medium .
en - face images were acquired starting at the surface of the tissue in 510 m increments in depth , until the deepest part of the tissue where meaningful signals could still be obtained . in our case , we could image kidney sections up to a depth of 6070 m .
the native field of view is 0.8 mm by 0.8 mm ; however larger fields of view can be acquired by image tiling .
imaging of a 2.72 mm 2.72 mm field - of - view with 10 optical sections , reaching a depth of 5060 m within the tissue ( representing a typical sample imaging session ) took ~7 min .
two to eight images were acquired from different areas in a given sample , depending on the size of the specimen and areas of interest .
the images were processed in real time with a digital imaging and communication in medicine viewer and saved . they were read and further processed with image j software ( national institutes of health , bethesda , md , usa ) , if necessary .
speckle noise was minimized using gaussian filtering in adobe photoshop cs5 ( san jose , ca , usa ) .
the research pathologist , who had previous experience in analyzing ffoct images organized images into two sets : training and validation .
these sets were shown to an attending uropathologist at our institution for a blinded analysis .
thus , he was first shown the training set to familiarize him with the signatures of nonneoplastic and neoplastic kidney tissue on ffoct ( as noted by the research pathologist and subsequently confirmed on h&e ) .
the training set comprised of a total of 13 images ; 5 from nonneoplastic tissues and 8 from tumors ( 3 = clear cell renal cell carcinoma , 3 = chromophobe rcc and 2 = papillary rcc ) .
papillary urothelial carcinoma or benign tumors ( cystic nephroma ( cn ) and angiomyolipoma [ aml ] ) were not included in the training set due to their small sample size .
the images used for the training set were excluded from the blinded analysis . since on an average 28 images were acquired from both nonneoplastic and neoplastic tissue , this exclusion did not affect our blinded analysis .
this set comprised a total of 67 images ( normal = 27 and tumor = 40 ) .
the uropathologist was asked to categorize these images as nonneoplastic or neoplastic and , if neoplastic , as benign or malignant .
he was also asked to characterize the tumor type based on its architecture and unique ffoct signatures .
later , these results were compared with their corresponding h&e to assess the diagnostic accuracy of ffoct .
tumors were classified according to the international society of urological pathology vancouver classification of renal neoplasia .
twenty - five adult subjects who were diagnosed with kidney tumor on clinical imaging and underwent nephrectomies ( partial or radical ) at our institution participated in this institutional review board approved the study .
the freshly excised nephrectomy specimens ( n = 25 ) received in surgical pathology were processed according to standard protocol .
one section each from the tumor and nonneoplastic kidney were collected fresh in buffered saline and brought to the ffoct microscope for imaging . following ffoct imaging , the specimens were placed in 10% buffered formalin and submitted for routine histopathological examination .
a commercial ffoct system was used ( light - ct scanner , lltech sas , paris , france ) .
it is a modified high - resolution ffoct system ( 1.5 m transverse and 0.8 m axial resolution ) .
this system uses a spatially and temporally incoherent light source of low power ( quartz - halogen schott kl 1500 compact , mainz , germany ) .
transverse en - face tomographic images of the samples are obtained by the combination of interferential images acquired by a cmos camera .
the microscope utilizes two matched 10x per 0.3 na water immersion objectives ( olympus america , center valley , pa ) , one to collect reflections and backscattering signals from the specimen and the other to collect reflection signal from a reference mirror .
full - field optical coherence tomography showing ( a ) schematic diagram of the optical pathway and ( b ) photograph of the system used
the samples to be imaged were immersed in an isotonic solution of phosphate - buffered saline ( pbs ; 2.7 mm potassium chloride and 137 mm sodium chloride ; ph 7.5 ) and placed in a sample holder ( part of the light - ct system ) .
a silica cover - slip was placed on top of the sample , and the base of the holder was gently moved upward , to slightly flatten the sample .
a thick layer of silicone oil was applied on the silica cover - slip as the objective immersion medium .
en - face images were acquired starting at the surface of the tissue in 510 m increments in depth , until the deepest part of the tissue where meaningful signals could still be obtained . in our case , we could image kidney sections up to a depth of 6070 m .
the native field of view is 0.8 mm by 0.8 mm ; however larger fields of view can be acquired by image tiling .
imaging of a 2.72 mm 2.72 mm field - of - view with 10 optical sections , reaching a depth of 5060 m within the tissue ( representing a typical sample imaging session ) took ~7 min .
two to eight images were acquired from different areas in a given sample , depending on the size of the specimen and areas of interest .
the images were processed in real time with a digital imaging and communication in medicine viewer and saved . they were read and further processed with image j software ( national institutes of health , bethesda , md , usa ) , if necessary .
speckle noise was minimized using gaussian filtering in adobe photoshop cs5 ( san jose , ca , usa ) .
the research pathologist , who had previous experience in analyzing ffoct images organized images into two sets : training and validation .
these sets were shown to an attending uropathologist at our institution for a blinded analysis .
thus , he was first shown the training set to familiarize him with the signatures of nonneoplastic and neoplastic kidney tissue on ffoct ( as noted by the research pathologist and subsequently confirmed on h&e ) .
the training set comprised of a total of 13 images ; 5 from nonneoplastic tissues and 8 from tumors ( 3 = clear cell renal cell carcinoma , 3 = chromophobe rcc and 2 = papillary rcc ) .
papillary urothelial carcinoma or benign tumors ( cystic nephroma ( cn ) and angiomyolipoma [ aml ] ) were not included in the training set due to their small sample size .
the images used for the training set were excluded from the blinded analysis . since on an average 28 images were acquired from both nonneoplastic and neoplastic tissue , this exclusion did not affect our blinded analysis .
this set comprised a total of 67 images ( normal = 27 and tumor = 40 ) .
the uropathologist was asked to categorize these images as nonneoplastic or neoplastic and , if neoplastic , as benign or malignant .
he was also asked to characterize the tumor type based on its architecture and unique ffoct signatures .
later , these results were compared with their corresponding h&e to assess the diagnostic accuracy of ffoct .
tumors were classified according to the international society of urological pathology vancouver classification of renal neoplasia .
all four main components of the normal kidney that is , glomerulus , tubules , blood vessels and interstitium were readily identified on ffoct [ figure 2 ] .
these components were recognized based on their histomorphological architecture and amount of reflected or scattered light originating from different tissue types . the cortex was mainly comprised glomeruli and convoluted tubules [ figure 2a ] .
glomeruli appeared as a globular structure composed of a capillary tuft ( dull gray signal ) and surrounded by a signal - void bowman 's space [ figure 2a ] .
convoluted tubules , that is , proximal and distal tubules , appeared as tubular structures of varying size and shapes with an epithelial lining ( dull gray signal ) [ figure 2a ] .
medullary rays composed of straight tubules lined by epithelial cells ( dull gray signal ) were identified in the medulla [ figure 2b ] .
the interstitium comprised connective tissue had bright signal mainly originating from collagen fibers [ figure 2c ] .
blood vessels appeared as luminal , signal - void structures of varying calibers without any epithelial lining .
thick muscular wall ( dull gray signal ) was identified in large caliber blood vessels [ figure 2c ] .
all the above mentioned histomorphological features seen in nonneoplastic kidney tissue were confirmed on their corresponding h&e slides [ figure 2d f ] .
full - field optical coherence tomography ( a - c ) and corresponding h&e image ( d - f ) of nonneoplastic kidney .
( c ) large caliber blood vessel ( arrow ) surrounded by bright interstitium ( arrowhead ) . full - field optical coherence tomography ( a - c ) ; scale bars = 0.5 mm .
insets 2.5 , zoom of images a and b , respectively . h&e ( d - f ) ; total magnifications = 100 in addition to identifying all the major components of nonneoplastic kidney , we could reliably differentiate nonneoplastic from neoplastic tissue on ffoct .
further , based on their architecture , tumors were broadly classified as papillary and nonpapillary ( sheets or trabeculae of cells ) on ffoct [ figures 3 and 4 , table 1 ] . full - field optical coherence tomography ( a and b ) and corresponding h&e images of ( c and d ) of nonpapillary kidney tumors . ( a ) clear cell renal cell carcinoma with sheets of cells ( arrow ) and stroma ( arrowhead ) .
( b ) chromophobe renal cell carcinoma with sheets of cells ( arrow ) and bright stroma ( arrowheads ) .
cells have abundant homogenous cytoplasm ( inset ; arrowhead ) . full - field optical coherence tomography ( a and b ) ; scale bars = 0.5 mm
. insets = 3 zoom of images a and b , respectively . h&e ( c and d ) ; total magnifications = 100 full - field optical coherence tomography ( a - c ) and corresponding h&e images of ( d - f ) of papillary kidney tumors .
( b ) papillary renal cell carcinoma showing papillae ( arrow ) filled with large bright cells ( arrowhead ; inset ) confirmed as histiocytes ( arrow ) on corresponding h&e ( e ) .
( c ) papillary urothelial carcinoma showing thick papillae with fibrovascular core ; collagen bright signal adjacent to signal void oval blood vessel ( arrow ; inset with arrowhead ) .
full - field optical coherence tomography ( a - c ) ; scale bars = 0.25 mm . insets = 2 zoom of images b and c , respectively , h&e ( d - f ) ; total magnifications = 200 signatures of kidney tumors on ffoct as compared to morphological features on h and e the nonpapillary tumors that were imaged in our study mainly comprised clear cell rcc ( ccrcc ) and chromophobe rcc ( chrcc ) , as diagnosed on h&e [ figure 3 ] .
ccrcc had cells ( dull gray signals ) with indistinct cell borders and central signal - void nucleus .
bright punctate particles were observed in the cytoplasm of these cells [ figure 3a ] .
we hypothesize that the bright punctate signal represents glycogen and/or lipid droplets in the cytoplasm of ccrcc .
in contrast , the ccrcc cells on h&e have clear cytoplasm , since the glycogen and lipid get washed out during tissue processing [ figure 3c ] .
chrcc , on the other hand , had large cells with distinct cell border and homogenous cytoplasm ( dull gray signal ) [ figure 3b ]
. thickened blood vessels with collagen proliferation ( bright signal ) in their wall ( dysmorphic blood vessels on h&e ) were also identified in chrcc [ figure 3b and d ] .
likewise , the papillary tumors imaged in our study mainly comprised of papillary rcc ( prcc ) and puc [ figure 4 ] . prcc had papillae lined by columnar - cuboidal epithelial cells ( dull gray signal ) [ figure 4a and d ] . in the majority of the prcc , we identified large cells with very bright cytoplasm in the cores of the papillae [ figure 4b ] .
these large , bright cells were confirmed as histiocytes on corresponding h&e [ figure 4e ] . on the contrary , puc
had papillae lined by multi - layered urothelium ( dull gray signal ) with central fibro - vascular core [ figure 4c ] .
the fibrovascular core had collagen ( bright signal ) and blood vessels ( elongated signal void spaces ) without histiocytes , as confirmed on h&e [ figure 4f ] .
in addition to the malignant kidney tumors , we also imaged two types of benign kidney tumors that is , aml and cn [ figure 5 ] .
adipocytes appeared as large polygonal cells with distinct cell border and signal - void cytoplasm [ figure 5a ] . surrounding collagen ( bright signal ) present in the interstitium and vascular walls
cystic nephroma had mostly cystic structures ( signal - void ) separated by fibrous tissue septae ( bright signal ) [ figure 5b ] .
these morphological features in aml and cn were confirmed on their corresponding h&e [ figure 5c and d ] . full - field optical coherence tomography ( a and b ) and corresponding h&e images of ( c and d ) of benign kidney tumors .
( a ) angiomyolipoma showing signal void polygonal adipocytes ( arrows ) and bright connective tissue from collagen ( arrowhead ) .
( b ) cystic nephroma showing large signal void cyst ( * ) lined by single layered epithelium with dull gray signal ( arrow and inset with arrowhead ) embedded in thick collagenous tissue ( bright signal ; arrowhead ) .
full - field optical coherence tomography ; scale bars ( a ) = 0.25 mm , ( b ) = 0.5 mm .
inset 2 zoom of images b. h&e ( c and d ) ; total magnifications = 200 in addition to images acquired by the ffoct prototype used in this study , some of the images were also acquired using an experimental ffoct system equipped with a 30 olympus objective with a much higher na of 1.05 [ figure 6 ] . figure 6 shows an image of nonneoplastic rat 's kidney mainly comprised tubules with a better lateral resolution as compared to our system . full - field optical coherence tomography image from rat 's kidney showing tubules ( arrows ) at a relatively higher resolution , acquired by an experimental full - field optical coherence tomography system equipped with a 30 olympus objective ( na ; 1.05 ) .
field of view = 260 260 in our study , a total of 25 kidney tumors were imaged with ffoct . of these ,
21 were malignant ( 12 ccrcc , 4 prcc , 4 chrcc and 1 puc ) and 4 were benign ( 2 aml , 2 cn ) , as diagnosed on h&e .
for the blinded analysis , a total of 67 images ( normal = 27 and tumor = 40 ) were analyzed by an uropathologist at our institute .
neoplastic tissue was correctly identified in all 40/40 ( 100% ) images included in this analysis .
further , all benign tumors ( 2 cases each of aml and cystic nephroma ) , that is , 4/4 ( 100% ) were called benign and all malignant tumors , that is , 21/21 cases were correctly labeled as malignant by the uropathologist .
in addition to accurately identifying and differentiating neoplastic from nonneoplastic kidney tissue , and benign from malignant tumors , the uropathologist also subtyped the tumors .
the subtyping was based on the architecture , that is , predominantly papillary versus predominantly solid pattern of the tumor and also on the unique ffoct signatures as described in the results above .
the bright punctate signal in the cytoplasm was a consistent feature of ccrcc that helped in correctly diagnosing 9/12 ( 75% ) cases of ccrcc .
of the remaining 3/12 ccrcc cases that were not correctly diagnosed on ffoct , two cases had poor quality images , and one case had cystic structures with the very little cellular area to evaluate . similarly , chrcc was correctly diagnosed in 2/4 ( 50% ) cases .
the two misdiagnosed cases of chrcc were diagnosed as ccrcc . on the other hand , all cases of prcc , that is , 4/4 ( 100% ) and puc 1/1 ( 100% ) were correctly diagnosed on ffoct .
thus we obtained a total diagnostic accuracy of subtyping the tumors in 20/25 ( 80% ) cases .
case distribution of kidney tumors and results of blinded tumosr subtype diagnostic accuracy no formal power calculations , such as positive and negative predictive value , were performed in this study due to the small sample size of the tissues imaged .
all four main components of the normal kidney that is , glomerulus , tubules , blood vessels and interstitium were readily identified on ffoct [ figure 2 ] .
these components were recognized based on their histomorphological architecture and amount of reflected or scattered light originating from different tissue types . the cortex was mainly comprised glomeruli and convoluted tubules [ figure 2a ] .
glomeruli appeared as a globular structure composed of a capillary tuft ( dull gray signal ) and surrounded by a signal - void bowman 's space [ figure 2a ] .
convoluted tubules , that is , proximal and distal tubules , appeared as tubular structures of varying size and shapes with an epithelial lining ( dull gray signal ) [ figure 2a ] .
medullary rays composed of straight tubules lined by epithelial cells ( dull gray signal ) were identified in the medulla [ figure 2b ] .
the interstitium comprised connective tissue had bright signal mainly originating from collagen fibers [ figure 2c ] .
blood vessels appeared as luminal , signal - void structures of varying calibers without any epithelial lining .
thick muscular wall ( dull gray signal ) was identified in large caliber blood vessels [ figure 2c ] .
all the above mentioned histomorphological features seen in nonneoplastic kidney tissue were confirmed on their corresponding h&e slides [ figure 2d f ] .
full - field optical coherence tomography ( a - c ) and corresponding h&e image ( d - f ) of nonneoplastic kidney .
( c ) large caliber blood vessel ( arrow ) surrounded by bright interstitium ( arrowhead ) . full - field optical coherence tomography ( a - c ) ; scale bars = 0.5 mm .
insets 2.5 , zoom of images a and b , respectively . h&e ( d - f ) ; total magnifications = 100
in addition to identifying all the major components of nonneoplastic kidney , we could reliably differentiate nonneoplastic from neoplastic tissue on ffoct .
further , based on their architecture , tumors were broadly classified as papillary and nonpapillary ( sheets or trabeculae of cells ) on ffoct [ figures 3 and 4 , table 1 ] . full - field optical coherence tomography ( a and b ) and corresponding h&e images of ( c and d ) of nonpapillary kidney tumors . ( a ) clear cell renal cell carcinoma with sheets of cells ( arrow ) and stroma ( arrowhead ) .
( b ) chromophobe renal cell carcinoma with sheets of cells ( arrow ) and bright stroma ( arrowheads ) .
full - field optical coherence tomography ( a and b ) ; scale bars = 0.5 mm . insets = 3 zoom of images a and b , respectively . h&e ( c and d ) ; total magnifications = 100 full - field optical coherence tomography ( a - c ) and corresponding h&e images of ( d - f ) of papillary kidney tumors .
( b ) papillary renal cell carcinoma showing papillae ( arrow ) filled with large bright cells ( arrowhead ; inset ) confirmed as histiocytes ( arrow ) on corresponding h&e ( e ) .
( c ) papillary urothelial carcinoma showing thick papillae with fibrovascular core ; collagen bright signal adjacent to signal void oval blood vessel ( arrow ; inset with arrowhead ) .
full - field optical coherence tomography ( a - c ) ; scale bars = 0.25 mm . insets = 2 zoom of images b and c , respectively , h&e ( d - f ) ; total magnifications = 200 signatures of kidney tumors on ffoct as compared to morphological features on h and e the nonpapillary tumors that were imaged in our study mainly comprised clear cell rcc ( ccrcc ) and chromophobe rcc ( chrcc ) , as diagnosed on h&e [ figure 3 ] .
ccrcc had cells ( dull gray signals ) with indistinct cell borders and central signal - void nucleus .
bright punctate particles were observed in the cytoplasm of these cells [ figure 3a ] .
we hypothesize that the bright punctate signal represents glycogen and/or lipid droplets in the cytoplasm of ccrcc . in contrast
, the ccrcc cells on h&e have clear cytoplasm , since the glycogen and lipid get washed out during tissue processing [ figure 3c ] .
chrcc , on the other hand , had large cells with distinct cell border and homogenous cytoplasm ( dull gray signal ) [ figure 3b ]
. thickened blood vessels with collagen proliferation ( bright signal ) in their wall ( dysmorphic blood vessels on h&e ) were also identified in chrcc [ figure 3b and d ] .
likewise , the papillary tumors imaged in our study mainly comprised of papillary rcc ( prcc ) and puc [ figure 4 ] .
prcc had papillae lined by columnar - cuboidal epithelial cells ( dull gray signal ) [ figure 4a and d ] . in the majority of the prcc
, we identified large cells with very bright cytoplasm in the cores of the papillae [ figure 4b ] .
these large , bright cells were confirmed as histiocytes on corresponding h&e [ figure 4e ] . on the contrary ,
puc had papillae lined by multi - layered urothelium ( dull gray signal ) with central fibro - vascular core [ figure 4c ] .
the fibrovascular core had collagen ( bright signal ) and blood vessels ( elongated signal void spaces ) without histiocytes , as confirmed on h&e [ figure 4f ] .
in addition to the malignant kidney tumors , we also imaged two types of benign kidney tumors that is , aml and cn [ figure 5 ] .
adipocytes appeared as large polygonal cells with distinct cell border and signal - void cytoplasm [ figure 5a ] . surrounding collagen ( bright signal ) present in the interstitium and vascular walls
cystic nephroma had mostly cystic structures ( signal - void ) separated by fibrous tissue septae ( bright signal ) [ figure 5b ] .
these morphological features in aml and cn were confirmed on their corresponding h&e [ figure 5c and d ] . full - field optical coherence tomography ( a and b ) and corresponding h&e images of ( c and d ) of benign kidney tumors . ( a ) angiomyolipoma showing signal void polygonal adipocytes ( arrows ) and bright connective tissue from collagen ( arrowhead ) .
( b ) cystic nephroma showing large signal void cyst ( * ) lined by single layered epithelium with dull gray signal ( arrow and inset with arrowhead ) embedded in thick collagenous tissue ( bright signal ; arrowhead ) .
full - field optical coherence tomography ; scale bars ( a ) = 0.25 mm , ( b ) = 0.5 mm .
inset 2 zoom of images b. h&e ( c and d ) ; total magnifications = 200 in addition to images acquired by the ffoct prototype used in this study , some of the images were also acquired using an experimental ffoct system equipped with a 30 olympus objective with a much higher na of 1.05 [ figure 6 ] . figure 6 shows an image of nonneoplastic rat 's kidney mainly comprised tubules with a better lateral resolution as compared to our system . full - field optical coherence tomography image from rat 's kidney showing tubules ( arrows ) at a relatively higher resolution , acquired by an experimental full - field optical coherence tomography system equipped with a 30 olympus objective ( na ; 1.05 ) .
in our study , a total of 25 kidney tumors were imaged with ffoct . of these , 21 were malignant ( 12 ccrcc , 4 prcc , 4 chrcc and 1 puc ) and 4 were benign ( 2 aml , 2 cn ) , as diagnosed on h&e .
for the blinded analysis , a total of 67 images ( normal = 27 and tumor = 40 ) were analyzed by an uropathologist at our institute .
likewise , neoplastic tissue was correctly identified in all 40/40 ( 100% ) images included in this analysis .
further , all benign tumors ( 2 cases each of aml and cystic nephroma ) , that is , 4/4 ( 100% ) were called benign and all malignant tumors , that is , 21/21 cases were correctly labeled as malignant by the uropathologist .
in addition to accurately identifying and differentiating neoplastic from nonneoplastic kidney tissue , and benign from malignant tumors , the uropathologist also subtyped the tumors .
the subtyping was based on the architecture , that is , predominantly papillary versus predominantly solid pattern of the tumor and also on the unique ffoct signatures as described in the results above .
the bright punctate signal in the cytoplasm was a consistent feature of ccrcc that helped in correctly diagnosing 9/12 ( 75% ) cases of ccrcc .
of the remaining 3/12 ccrcc cases that were not correctly diagnosed on ffoct , two cases had poor quality images , and one case had cystic structures with the very little cellular area to evaluate . similarly , chrcc was correctly diagnosed in 2/4 ( 50% ) cases .
the two misdiagnosed cases of chrcc were diagnosed as ccrcc . on the other hand , all cases of prcc ,
that is , 4/4 ( 100% ) and puc 1/1 ( 100% ) were correctly diagnosed on ffoct .
thus we obtained a total diagnostic accuracy of subtyping the tumors in 20/25 ( 80% ) cases .
case distribution of kidney tumors and results of blinded tumosr subtype diagnostic accuracy no formal power calculations , such as positive and negative predictive value , were performed in this study due to the small sample size of the tissues imaged .
in this study , we have demonstrated the ability of ffoct to identify all major components of a normal kidney , such as glomeruli , tubules , blood vessels and interstitium . besides identifying normal components of the kidney , ffoct could reliably differentiate neoplastic from the nonneoplastic tissue .
further , kidney tumors could be broadly classified as papillary ( prcc and puc ) and nonpapillary ( ccrcc and chrcc ) based on their architecture . in addition , some of the tumors such as ccrcc and prcc had unique ffoct signatures that helped in their diagnosis .
ccrcc was characterized by the presence of the bright punctate cytoplasmic signal ( representing glycogen and/or lipid content ) , and the majority of prcc had large bright cells in their papillary core ( representing histiocytes ) .
ffoct has been previously used to characterize various ex vivo tissues and to differentiate neoplastic from nonneoplastic tissue in several organs other than kidney . here , for the first time
furthermore , a blinded analysis was also conducted by an attending uropathologist to validate the results .
ffoct offers several advantages making it a potential rapid , real - time imaging tool .
one of the major advantages is the ability to generate high - resolution images ( 12 m lateral resolution ) reminiscent of histopathology from fresh ex vivo tissue without tissue processing or use of contrast agents or dyes .
another advantage is the relatively fast speed of image acquisition , i.e. , a single plane of ~3 mm can be acquired in ~ 43 s. in addition , images can also be acquired in
furthermore , the use of a regular halogen lamp as the light source ensures the relative safety of ffoct for use in human tissue ( no potential laser damage ) .
finally , the user - friendly format and compact size of ffoct makes its installation feasible in busy and tight spaces such as intra - operative suites or gross rooms of surgical pathology .
therefore , based on our results and the above - mentioned advantages of ffoct , we envision several ex vivo clinical applications .
ffoct , when used during a preoperative biopsy procedure , has the potential to replace fine - needle aspiration cytology and/or touch imprint cytology for rapid on - site evaluation of tissue to confirm its diagnostic adequacy .
this might help reduce the rate of a nondiagnostic biopsy on final histopathology and subsequently repeat biopsies and its complications , as well as cost .
in addition , since the tissue is not processed in any way for ffoct , this tissue can be triaged post - ffoct evaluation for ancillary studies , ( e.g. , immunohistochemistry or genomics ) .
similarly , ffoct , when used intra - operatively , can potentially replace fsa for margin assessment during partial nephrectomies .
since ffoct does not require tissue processing , it can analyze tissues faster , and without causing any tissue artifacts . besides the use of ffoct for diagnosis and management of renal tumors , it could also play an important role in the diagnostic workflow of medical kidney disease ( mkd ) . for the evaluation of mkd , renal biopsy tissue is routinely divided up into separate samples for light microscopy , immunofluorescence , and electron microscopy evaluation .
although , dissecting microscope has a high accuracy of detecting glomeruli , but due to lack of cellular resolution it may at times fail to differentiate between various simulators of glomeruli . the ability of ffoct to reliably identify normal renal parenchyma at the cellular level could provide with a more reliable way of triaging renal biopsies .
further , a computer - assisted algorithm could be developed from the ffoct images to help guide nephrologists into triaging the quality of their cases remotely before they are sent to pathology .
however , the clinical ffoct prototype ( light - ct ) that was used in our study has some limitations .
though ffoct could reliably identify and differentiate all neoplastic from nonneoplastic kidney tissue , and malignant from benign tumors , correct tumor subtyping was only achieved in 80% of the cases imaged .
this was mainly due to lack of enough cellular and nuclear details to classify the tumors .
this limitation is predominantly a function of the use of a relative low na ( 0.3 ) objective in this prototype , along with the presence of speckle artifacts that further reduces effective resolution . as shown in the results , higher resolution images are now feasible to acquire using the experimental ffoct system equipped with a 30 olympus objective with a much higher na of 1.05 .
this ffoct prototype shows promising results and may be used in the future to conduct similar studies with a larger sample size .
consequently , it is our opinion that while the current prototype is excellent for a quick diagnostic impression on clinical specimens where a decision can be made on architectural information alone , it will require better lateral resolution for successfully addressing clinical questions that require cellular and/or nuclear information .
based on our study , we foresee ffoct as a valuable real - time imaging tool for rapid evaluation and triaging of fresh ex vivo kidney tissue . we posit that ffoct could help improve preoperative and intra - operative diagnosis , and thus facilitate better clinical management of patients with kidney tumors .
| background : full - field optical coherence tomography ( ffoct ) is a real - time imaging technique that rapidly generates images reminiscent of histology without any tissue processing , warranting its exploration for evaluation of ex vivo kidney tissue.methods:fresh tissue sections from tumor and adjacent nonneoplastic kidney ( n = 25 nephrectomy specimens ; clear cell renal cell carcinoma ( ccrcc ) = 12 , papillary rcc ( prcc ) = 4 , chromophobe rcc ( chrcc ) = 4 , papillary urothelial carcinoma ( puc ) = 1 , angiomyolipoma ( aml ) = 2 and cystic nephroma = 2 ) were imaged with a commercial ffoct device .
sections were submitted for routine histopathological diagnosis.results:glomeruli , tubules , interstitium , and blood vessels were identified in nonneoplastic tissue . in tumor sections ,
the normal architecture was completely replaced by either sheets of cells / trabeculae or papillary structures .
the former pattern was seen predominantly in ccrcc / chrcc and the latter in prcc / puc ( as confirmed on h&e ) .
although the cellular details were not very prominent at this resolution , we could identify unique cytoplasmic signatures in some kidney tumors .
for example , the hyper - intense punctate signal in the cytoplasm of crcc represents glycogen / lipid , large cells with abundant hyper - intense cytoplasm representing histiocytes in prcc , and signal - void large polygonal cell representing adipocytes in aml . according to a blinded analysis
was performed by an uropathologist , all nonneoplastic tissues were differentiated from neoplastic tissues .
further , all benign tumors were called benign and malignant were called malignant . a diagnostic accuracy of 80%
was obtained in subtyping the tumors.conclusion:the ability of ffoct to reliably differentiate nonneoplastic from neoplastic tissue and identify some tumor types makes it a valuable tool for rapid evaluation of ex vivo kidney tissue e.g. for intraoperative margin assessment and kidney biopsy adequacy .
recently , higher resolution images were achieved using an experimental ffoct setup .
this setup has the potential to further increase the diagnostic accuracy of ffoct . |
plasmodium vivax ( p. vivax ) is the second widespread malaria species that causes disease in human and imposes sizeable socioeconomic burden and public health difficulty on many countries , particularly in asia and south and central america ( 1 ) .
although , p. vivax is responsible for more than 50% of malaria morbidity outside sub - saharan africa , but little consideration for control and research has been dedicated to this parasite ( 2 ) . at present , about 2.8 billion people universally are at risk of p. vivax infection and occurrence of the disease is nearly 132391 million cases each year ( 3 ) . in a nutshell , in malaria life cycle ,
being bit by female anopheles mosquitoes , sporozoites are transferred to human and infection is initiated . within hepatocytes , the sporozoites reproduce and increase in quantity to thousands of merozoites , which attack the red blood cells ( rbcs ) in the next stage . in the infected rbcs , the small ring shape changes through trophozoite to schizont , in which it bursts and liberates more merozoites ( 4 ) . up to now
, some problems such as non cultivable nature of p. vivax , caused limitations in the study of its molecular biology , but genetic diversity and population organization of this parasite have become more clear by sequencing and genetic engineering including cloning methods ( 5 ) .
several p. vivax antigens have been proposed as detectable potential candidates ( 6 ) , among which c - terminal region of pvmsp-1 has high expression on the mature merozoites surface as well as mass protein production , that it has been proven to take part in the parasite invasion to the erythrocyte .
specific antibodies against msp-1 , have been particularly shown react to the c - terminal region ( 33-kda and 19-kda sub fragments ) ( 79 ) .
antigenic variation is one of the limitative agents in antibody detection that could be due to haplotype variations on target gene .
it can ultimately affect the protein conformation , affinity of antibody - antigen and serological test results .
little information is available regarding the genetic polymorphism of msp-142 among iranian p. vivax population . in this study , in order to assess the nature of iranian p. vivax isolate , molecular diversity of cloned pvmsp-142
kda gene was analyzed .
in this study , 11 isolates of chabahar district ( sistan and balouchestan province ) that had p. vivax infection symptoms were chosen and sequenced in order to surveying their similarities .
one out of 11 mentioned isolates which had highest homology was selected to cloning process . .
the parasite genomic dna was extracted from the whole blood by genomic dna extraction kit , dng plus ( cinna gene , iran , dn8118c ) using the kit manufacturer s guidelines .
continuously , genomic dna quantity and quality was controlled by electrophoresis on 0.8% agarose gel and a biophotometer ( ependorf ) at 260 and 280 nm .
amplification from 42 kda partial regions of pvmsp-1 gene was done which included 19 kda and 33kda fragments .
the primers were designed on the basis of the sequence of pvmsp-142
kda gene , ( genbank : accession no : dq907673 ) .
the following primers were used for sequencing : msp1.42f ( 25mer ) ( 5-ggatccgaccaagtaacaacgggag-3 ) , msp1.42r ( 25mer ) ( 5-gaattccaaagagtggctcagaacc-3 ) .
the pcr was performed in a pcr tube containing : 200 ng ( 1.5l ) extracted dna as template , 20 pmol ( 0.25 l ) of each primer , 7.5 l of pcr master mix 2x that contained taq and 5.5 l of ddh2o .
the objective gene was amplified for 30 cycles ( initial denaturation at 96 c for 5 min , 96 c for 30s , 58 c for 30s and 72 c for 1 min and final extension for 20 min ) subsequently , the pcr product was controlled on 1% agarose gel against a standard dna ladder ( fermentase co. ) .
pcr products that consisted of a single specific band can be directly ligated to t - vectors .
however , the removal of the impurities such as primers and nonspecific products by gel separation causes increase in the percentage of colonies containing the correct inserts . thermo - stable dna polymerase which does not preferentially add a 3-a at the ends of the pcr products is essential to removal of that enzyme by gel separation .
purification and recovery of the dna from agarose gel will be explained in the next sections .
purified dna fragment was inserted into ptz57r / t that provided by the following protocol .
any plasmid could be selected to gratifies our requirements including the plasmid contains a unique blunt - end restriction site in the multiple cloning site ( in this study , the ecor v site of the ptz57r plasmid was used that has blue / white color selection ) .
digesting plasmids were performed in a 0.5 ml microcentrifuge tube containing : 25 l plasmid dna ( 2g ) , 4 l of 10x ecor v buffer , ( 10 unit ) 1 l of ecor v ( fermentase co. ) and dd h2o up to 40l .
then it was mixed by gentle vortex , centrifuged and incubated at 37 c for 2 hours . in the next step ,
2 l of the mixture was taken and run on a 1% agarose gel to make sure the digestion was completed .
thereafter it was incubated to 65 c by water bath for 10 min at the end of digestion ( fig .
a : lane1 : intact plasmid ptz57r , lane2 : digested plasmid ptz57r by ecorv , lane3 : size marker : 1 kb .
b : lane1 : recombinant plasmid , lane2 : intact plasmid , lane3 : size marker1 kb .
c : lane1 : ( a : separated pcr product from digested recombinant plasmid ) , lane2 : intact recombinant plasmid , lane3 : size marker1 kb taq polymerase and dttp were used to add a 3-t to the blunt - ended plasmid .
briefly , the making t - overhangs was performed in a 200 l pcr tube containing : 40 l blunt - ended plasmid dna , 5 l of 10 x pcr buffer ( mgcl2 free ) , 2.5 l of mgcl2 ( 250 mm ) , 0.5 l of dttp ( 100 mm ) , 2 l of taq polymerase ( 5 u/l ) .
it was mixed by gentle vortex , centrifuged shortly and incubated at 72 c for 2 h. t - vectors were separated from the self - ligated and concatemerized plasmid dna on a 1% agarose gel by 0.5 g / ml of ethidium bromide .
the dna bands were visualized by a hand - held long wave ( 365 nm ) uv light .
the gel slice transferred to a 2 ml micro centrifuge tube , and then t - vectors were purified and recovered by silica bead dna gel extraction # k0513 ( fermentas co. ) via the kit manufacturer s guidelines .
the density of the purified t - vectors was determined by running 1 l of the t - vector in compared to standard dna ladder in a 1% agarose gel at 5 volts / cm for 45 min and then compared the comparative brilliantness of the bands .
1:3 molar ratio of t - vector to insert dna was recommended , but the amount of a - tailed dna solution in a 10 l ligation should not be more than 2 l . in a sterile 0.5 ml micro centrifuge tube , added : 2 l t - vector , 2 l of a - tailed dna , 1 l of 10 x ligation buffer , 1 l of t4 dna ligase ( 23 u/l ) and 4 l of ddh2o .
it was mixed gently , centrifuged briefly and incubated at 14 c for overnight ( fig .
before transformation , luria - bertani ( lb ) agar plates contained 100 g / ml of ampicillin , were prepared and spreaded with 5-bromo-4-chloro-3-indolyl--d - galactoside ( x - gal ) and isopropylthio--d - galactoside ( iptg ) .
for each ligation reaction , 50 l aliquoted of frozen competent cells ( top 10 ) was thawed on ice and added 2 l of the ligation reaction to the competent cells and mixed gently by stirring with the pipette tip .
the cells were incubated on ice for 30 min then heats shocked for 30 s in the 42 c water bath , and then were immediately placed on ice for 2 min .
the transformed cells were spreaded on each labeled lb - ampicillin plate with x - gal and iptg .
the positive colonies that had white color were identified either by restriction enzyme and screening by pcr method after transformation .
pcr screening was carried out with same primers that be used for pcr amplification for insert production .
for screening by restriction enzyme method , the insert was released by digestion with two unique restriction enzymes ( with cutting sites , ecor1 : gaattc and bamh1 : ggatcc ) from the multiple cloning sites , and the insert size was confirmed by agarose gel electrophoresis ( fig .
pcr product of pvmsp-1 42 kda was directly analyzed on abi prismtm 310 automated sequencer to determine p. vivax variation ( strain / haplotype ) in the infected patient .
both directions of our sequences were aligned and edited using sequencher tm 4.0.4 software for pc ( gene codes corporation ) and mega 5 software for phylogenetic analysis and then were compared with some genbank sequences for their similarity ( 10 ) .
a phylogenetic hypothesis of p. vivax was generated with pvmsp-1 42 kda using the nonparametric bootstrapping , neighbor joining method .
in this study , 11 isolates of chabahar district ( sistan and balouchestan province ) that had p. vivax infection symptoms were chosen and sequenced in order to surveying their similarities .
one out of 11 mentioned isolates which had highest homology was selected to cloning process . .
the parasite genomic dna was extracted from the whole blood by genomic dna extraction kit , dng plus ( cinna gene , iran , dn8118c ) using the kit manufacturer s guidelines .
continuously , genomic dna quantity and quality was controlled by electrophoresis on 0.8% agarose gel and a biophotometer ( ependorf ) at 260 and 280 nm .
amplification from 42 kda partial regions of pvmsp-1 gene was done which included 19 kda and 33kda fragments .
the primers were designed on the basis of the sequence of pvmsp-142
kda gene , ( genbank : accession no : dq907673 ) .
the following primers were used for sequencing : msp1.42f ( 25mer ) ( 5-ggatccgaccaagtaacaacgggag-3 ) , msp1.42r ( 25mer ) ( 5-gaattccaaagagtggctcagaacc-3 ) .
the pcr was performed in a pcr tube containing : 200 ng ( 1.5l ) extracted dna as template , 20 pmol ( 0.25 l ) of each primer , 7.5 l of pcr master mix 2x that contained taq and 5.5 l of ddh2o .
the objective gene was amplified for 30 cycles ( initial denaturation at 96 c for 5 min , 96 c for 30s , 58 c for 30s and 72 c for 1 min and final extension for 20 min ) subsequently , the pcr product was controlled on 1% agarose gel against a standard dna ladder ( fermentase co. ) .
pcr products that consisted of a single specific band can be directly ligated to t - vectors .
however , the removal of the impurities such as primers and nonspecific products by gel separation causes increase in the percentage of colonies containing the correct inserts . thermo - stable dna polymerase which does not preferentially add a 3-a at the ends of the pcr products is essential to removal of that enzyme by gel separation .
purification and recovery of the dna from agarose gel will be explained in the next sections .
purified dna fragment was inserted into ptz57r / t that provided by the following protocol .
any plasmid could be selected to gratifies our requirements including the plasmid contains a unique blunt - end restriction site in the multiple cloning site ( in this study , the ecor v site of the ptz57r plasmid was used that has blue / white color selection ) .
digesting plasmids were performed in a 0.5 ml microcentrifuge tube containing : 25 l plasmid dna ( 2g ) , 4 l of 10x ecor v buffer , ( 10 unit ) 1 l of ecor v ( fermentase co. ) and dd h2o up to 40l .
then it was mixed by gentle vortex , centrifuged and incubated at 37 c for 2 hours . in the next step ,
2 l of the mixture was taken and run on a 1% agarose gel to make sure the digestion was completed .
thereafter it was incubated to 65 c by water bath for 10 min at the end of digestion ( fig .
a : lane1 : intact plasmid ptz57r , lane2 : digested plasmid ptz57r by ecorv , lane3 : size marker : 1 kb .
b : lane1 : recombinant plasmid , lane2 : intact plasmid , lane3 : size marker1 kb .
c : lane1 : ( a : separated pcr product from digested recombinant plasmid ) , lane2 : intact recombinant plasmid , lane3 : size marker1 kb
taq polymerase and dttp were used to add a 3-t to the blunt - ended plasmid . briefly , the making t - overhangs was performed in a 200 l pcr tube containing : 40 l blunt - ended plasmid dna , 5 l of 10 x pcr buffer ( mgcl2 free ) , 2.5 l of mgcl2 ( 250 mm ) , 0.5 l of dttp ( 100 mm ) , 2 l of taq polymerase ( 5 u/l ) .
it was mixed by gentle vortex , centrifuged shortly and incubated at 72 c for 2 h.
t - vectors were separated from the self - ligated and concatemerized plasmid dna on a 1% agarose gel by 0.5 g / ml of ethidium bromide .
the dna bands were visualized by a hand - held long wave ( 365 nm ) uv light .
the gel slice transferred to a 2 ml micro centrifuge tube , and then t - vectors were purified and recovered by silica bead dna gel extraction # k0513 ( fermentas co. ) via the kit manufacturer s guidelines .
the density of the purified t - vectors was determined by running 1 l of the t - vector in compared to standard dna ladder in a 1% agarose gel at 5 volts / cm for 45 min and then compared the comparative brilliantness of the bands .
. 1:3 molar ratio of t - vector to insert dna was recommended , but the amount of a - tailed dna solution in a 10 l ligation should not be more than 2 l . in a sterile 0.5 ml micro centrifuge tube ,
added : 2 l t - vector , 2 l of a - tailed dna , 1 l of 10 x ligation buffer , 1 l of t4 dna ligase ( 23 u/l ) and 4 l of ddh2o .
it was mixed gently , centrifuged briefly and incubated at 14 c for overnight ( fig .
before transformation , luria - bertani ( lb ) agar plates contained 100 g / ml of ampicillin , were prepared and spreaded with 5-bromo-4-chloro-3-indolyl--d - galactoside ( x - gal ) and isopropylthio--d - galactoside ( iptg ) .
for each ligation reaction , 50 l aliquoted of frozen competent cells ( top 10 ) was thawed on ice and added 2 l of the ligation reaction to the competent cells and mixed gently by stirring with the pipette tip .
the cells were incubated on ice for 30 min then heats shocked for 30 s in the 42 c water bath , and then were immediately placed on ice for 2 min .
the transformed cells were spreaded on each labeled lb - ampicillin plate with x - gal and iptg .
the positive colonies that had white color were identified either by restriction enzyme and screening by pcr method after transformation .
pcr screening was carried out with same primers that be used for pcr amplification for insert production .
for screening by restriction enzyme method , the insert was released by digestion with two unique restriction enzymes ( with cutting sites , ecor1 : gaattc and bamh1 : ggatcc ) from the multiple cloning sites , and the insert size was confirmed by agarose gel electrophoresis ( fig .
pcr product of pvmsp-1 42 kda was directly analyzed on abi prismtm 310 automated sequencer to determine p. vivax variation ( strain / haplotype ) in the infected patient .
both directions of our sequences were aligned and edited using sequencher tm 4.0.4 software for pc ( gene codes corporation ) and mega 5 software for phylogenetic analysis and then were compared with some genbank sequences for their similarity ( 10 ) .
a phylogenetic hypothesis of p. vivax was generated with pvmsp-1 42 kda using the nonparametric bootstrapping , neighbor joining method .
in fig . 1 , intact plasmid ptz57r , digested plasmid ptz57r by ecorv and digested recombinant ptz57r/ msp by bamhi and eco - ri restriction enzymes and expected insert band are presented . as fig .
2 shows an 1124 bp band has been demonstrated from extracted genomic dna by pcr .
lane 1 : pv msp-142 kda gene was nearly 1124bp long , lane 2 : size marker 1 kb the yield of pcr was cloned in ptz57r and then sequenced . in the iranian p. vivax isolate , as compared to the reference sal i sequence , 38 snp of pvmsp-142
kda , were identified . as fig .
4 shows , msp-1 42 kda phylogenetic tree based on bootstrap - neighbor joining method in iranian sequenced isolate ( msp 42-yyxxxxxx - iran 01 ) and other recorded sequences in genbank .
all of the mutations were localized in the pvmsp-133kda , while there was almost no variation in the msp-119 kda . 2 out of 38 mutations ( haplotype ) were novel in the 545 and 573 positions as compared to the homogeneous sequences from other surveyed countries ( fig . 3 , 4 ) .
bootstrap neighbor - joining consensus tree of pv - msp-142 kda data set by mega5 .
sequence of iranian isolate is shown for msp 42-yyxxxxxx - iran 01 in clad of indian and japonica sequences ( accession nos : eu 430479.1 , af435635.1 ) sequence alignment of pv msp-142 kda gene in p. vivax isolated from iran and correlated part of the isolated genes from other countries
in research on diagnostic potential for p. vivax malaria parasite subunits , the focus is on the c - terminal region of p. vivax msp-1 . as fig .
5 depicts , generally , msp1 is manufactured as a big protein ( 200 kda ) which is connected to the cell membrane by a glycophosphatidylinositol ( gpi ) anchor in the carboxyl terminus region ( 11 ) .
msp1 undergoes a series of proteolytic maturation changes at the same time as the merozoite unleashed from ( rbc ) and generates four polypeptide fragments of nearly 83 , 30 , 38 , and 42 kda from the n - terminus to c - terminus ( 12 ) , which stays as interconnected parts on the cell surface by the anchored c - terminal segment ( p42 ) ( 13 ) .
new rbcs are invaded rapidly by attachment of free merozoites induces second in a series cleavage of the p42 peptide to generate p33 , which is shed together with the previous fragments and p19 , abides by anchoring to the membrane of parasite as it invades the cell ( 14 , 15 ) .
high plentifulness and important function on the cell surface , probably caused msp1 to be a principal object of the host immune system and antibodies are identified on different regions of this protein ( 16 ) .
antibodies that recognize the c - terminal region of plasmodium falciparum msp-1 , inhibit the invasion of merozoites into the host erythrocytes in vitro and immunization of experimental animals with msp-119
kda also confers protective immunity ( 17 , 18 ) .
these findings demonstrate that msp-142
kda is a promising candidate antigen for blood stage vaccine development and diagnostic kits .
panel ( a ) shows primary processing , and ( b ) shows secondary processing in this study , the pv msp-142
kda was cloned , sequenced , and subsequently compared with homogeneous genes that previously had been recorded in genbank .
38 snp of pvmsp-142 kda , were recognized using the sequencher 4.0.4 and mega 5 programs .
pacheco et al . in indonesia tried to show the genetic diversity of the 42 kda fragment of msp-1 antigen in p. vivax .
they found that the msp-133
kda fragment exhibits greater genetic diversity than the msp-119 kda generally .
previous observations confirmed that the msp-119 kda fragment is more conserved than the msp-133 kda fragment ( 19 ) .
in present study , polymorphism of p. vivax msp-133 kda is not evenly spreaded , indeed there is a region of 70 bp in msp-133 kda where a clear excess of non - synonymous is observed in the overall msp-133
kda results , while there is closely no significant variation in the msp-119
kda .
two out of 38 mutations were new haplotypes ( 545 and 573 positions ) in the 33 kda fragment as compared to the homogeneous sequences from other countries including japan , turkey , usa , india , sumatra , vietnam , indonesia , riometa , china , france and reference sequence from sal - i ( 20 ) ( fig .
3 ) . due to the differentiation of msp1 amino acid sequences between plasmodium spp . , it is necessary to use recombinant msp-1 to detection antibody from p. vivax in iranian cases ( 21 ) .
compared the p. vivax msp-3 gene with ssrrna gene as genetic markers for the parasite detection . according to their results
the sensitivity of ssrrna gene was higher than the pvmsp-3 gene ( 100% vs. 95% ) .
they concluded that the pvmsp-3 gene can not be a suitable marker for detection of p. vivax in blood sample by pcr ( 22 ) .
one of the prominent problems in diagnostic kits is genetic polymorphisms that encoding on this region , within and between the p. vivax population .
therefore , polymorphism examination of this gene on disparate territories could be helpful in improving diagnostic kits based on antibody detection in malarious areas of iran .
shahbazi and colleagues in iran assessed the genetic structure of p. vivax population by sequence analysis of the merozoite surface protein 3 ( msp-3 ) gene .
moreover , their phylogenetic analysis did not show any significant geographical branching ( 23 ) .
studied the p. vivax dihydrofolate reductase ( pvdhfr ) mutations among 50 blood samples of symptomatic patients from 4 separated geographical regions of south - east iran .
they reported point mutations at residues 57 , 58 , 61 , and 117 by using the pcr - rflp method .
polymorphism at positions 58r , 117n , and 117 t of pvdhfr gene has been found in 12% , 34% , and 2% of isolates , respectively .
one of the endemic zones for p. vivax throughout the world is iran from which there are reported cases annually ( 25 ) .
asymptomatic carriers of p. vivax among treated patients have been shown as a major reservoir of parasites and maintenance of high levels of transmission in malarious areas of iran ( 26 ) .
although genetic polymorphisms in the regions of msp-1 in iranian p. vivax isolates has been previously analyzed , but little information is available regarding the genetic polymorphism of msp-142
kda among iranian p. vivax isolates . in this study ,
the genetic polymorphism of msp-142
kda in an iranian isolate was analyzed for a better understanding of the nature of iranian p. vivax .
thus , it is significant to investigate the molecular character of the parasite placed within iran and comparing with the same species in other regions .
predicted protein sequence of cloned pvmsp-142
kda gene obviously has a high degree of identity ( 97% ) with strong homology to the pv msp-142
kda gene of p. vivax .
asian isolates specially japan and india also have sequence similarity ( 95% ) pv msp-142kda gene from sal - i isolate ( as reference sequence ) . in general , diversity of anopheles mosquitoes , presence of several plasmodium species , biotic interactions and hybrid / mixed infections can affect the genotyping variation of plasmodium in low to high degree .
this might result in parasite pathogenicity , host specificity , establish and persist of infection , different clinical manifestation , transmission dynamics and antigenicity of infection .
the cloned pvmsp-142
kda gene can be used as a strong candidate for diagnostic kits based on antibody , antigen detection and vaccine development . | background : carboxy - terminal 42 kda region of plasmodium vivax merozoite surface protein-1 is considered as an important antigen in blood stage . since
, this region has been observed to be polymorphic among isolates of p. vivax , it is significant to survey on different regions of this antigen in various areas of the world.methods:in the present study , the genetic diversity of cloned pvmsp-142
kda gene from an iranian patient is analyzed .
parasite dna was extracted from a p. vivax - infected patient in iran .
the region of pvmsp-142
kda was amplified by pcr , cloned into ptz57r / t vector and then sequenced.results:sequencing of cloned pvmsp-142
kda gene clearly has a high degree of homology ( 95% ) with reference sal - i sequence and also with the homogeneous sequences from some studied countries ( 97% ) .
thirty eight snps ( single nucleotide polymorphism ) were identified in cloned pvmsp-142
kda gene which the mutations had localized in the 33 kda fragment ( pvmsp-133
kda ) , while there was nearly no variation in the 19 kda fragment ( pvmsp-119
kda ) . 2 out of 38 mutations were found as to be novel haplotypes.conclusion:high similarity of cloned pvmsp-142
kda gene in comparison to reference sequence and other sequences could be beneficial as a remarkable molecular marker for serological diagnostic kits of p. vivax in malarious neighboring countries of iran and around the world . |
it exists in many regions of the brain , such as ca1 of the hippocampus , visual cortex and cortical areas correlating with conscious perception .
it is known that synchronization is very important for information processing , such as predicting sensory input , and information codes . moreover ,
synchronous activity plays a crucial role in epileptic activity [ 6 , 7 ] , modulation of neurons about attention , memory and learning [ 9 , 10 ] , and cognitive functions .
since the discovery of long term potentiation ( ltp ) and ltd ( long term depression ) [ 1214 ] , it has been debated how synaptic modifications are correlated to neuron activities .
spike timing - dependent plasticity ( stdp ) is a form of synaptic modification discovered relatively recently , which depends on the relative timing of pre- and post - synaptic action potentials at a millisecond time scale [ 15 , 16 ] .
many experiments have proved the existence of stdp , such as in neocortical slices , hippocampus slice , hippocampal cell cultures , and tadpole rectum in vivo .
in addition , stdp provides powerful mechanisms for models of temporal pattern recognition , temporal sequence learning [ 22 , 23 ] , a continuous - time associative memory , coincidence detection [ 16 , 25 ] , navigation [ 26 , 27 ] and direction selectivity .
the interaction among neurons relies much on synaptic modification in which stdp is the only one that greatly expands the capability of hebbian learning to address temporally sensitive computational tasks .
for example , the result of learning - induced synchronization of a neural network at various developing stages using stdp rule is consistent with recent experimental observations .
furthermore , the comparison of synchronization between discontinuous anti - stdp(dc - astdp , see section 2 ) and constant connection has been investigated . following
it , the continuous stdp(c - stdp , see section 2 ) has also been studied by the same authors .
motivated by their work , we systemically discuss the roles of four types of stdp rules(c - stdp , dc - stdp , dc - astdp and in - stdp , see section 2 ) in frequency synchronization in the present paper , employing the same model with only values of some parameters different , such as aplus , tsyn , vslope , gmax ( see section 3 ) .
we then consider if the learning curves , which characterize the stdp rule , have certain effects on synchronization .
results indicate that synchronization strongly depends on the specific shape and the parameters of the stdp rule .
however , the optimal synchronization ranges for dc - stdp and in - stdp , got from regulating learning parameters , are not wider than those for the corresponding strongest constant connection respectively . as a result
, when we seek the reason , we discover that the synchronization mechanisms of above four stdp rules can be classified into two categories : ( i ) c - stdp and dc - astdp rules ; ( ii ) dc - stdp and in - stdp rules .
the synchronization mechanisms of the two categories are different . for c - stdp and dc - astdp rules ,
two neurons ' synchronization either relies on the balancing out potentiation and depression during one cycle consistent with the perspective of nowotny et al . or relies on the maximal synaptic conductance .
however , for dc - stdp and in - stdp rules , the synchronization windows are completely provided by the respective maximal synaptic conductance . as regards this finding
we consider two hh neurons with unidirectional activity - dependent excitatory or inhibitory synaptic coupling .
although such a configuration is too simple to find applications in brain information processing , it serves as a staring point for many model researches .
currents ,
( 1)cdvi(t)dt=gnami(t)3hi(t)(vi(t)ena)gkni(t)4 (vi(t)ek)gl(vi(t)el)isyn(t)+istim ,
where i = 1 , 2 .
each of the activation and inactivation variables yi(t ) = { ni(t ) , mi(t ) , hi(t ) } , i = 1 , 2 satisfies first - order kinetics ,
( 2)dyi(t)dt=y[vi(t)][1yi(t)]y[vi(t)]yi(t ) , i=1,2 .
istim is a constant input current forcing each neuron to spike with a constant , istim - dependent period , labeled as t1 and t2 .
the postsynaptic neuron would show another firing period t2 , when it is driven by the synaptic current , which is dependent on the postsynaptic potential v2(t ) , the reversal potential vrev , the activation variable s(t ) and its maximal conductance g(t ) ,
( 4)isyn(t)=g(t)s(t)(v2(t)vrev ) ,
where
( 5)ds(t)dt = s(v1(t))s(t)tsyn1(s(v1(t))),s(v)={tanh ( vvthvslope),for v > vth,0,otherwise .
the time - dependent synaptic coupling strength g(t ) ns is
( 6)g(t)=gmax 2(tanh ( grawgmidgslope)+1 ) .
therefore g(t ) always have values between 0 ns and gmax .
the bound imposed on g(t ) is artificially set to avoid unrealistically high synaptic conductance and negative conductance . in order to obtain biologically plausible synaptic conductance , several methods have been employed to limit the synaptic strength in literature , such as a negative total integral , artificial bounds , and self - limitation .
unless otherwise stated , we employ the self - limitation method which is characterized by a function tanh in our simulation .
the parameters of the model are
( 7)c=30 f , gl=1 s , el=64 mv , gna=360 s , ena=50 mv , gk=70 s , ek=95 mv , vth=20 mv , tsyn=25 ms , vslope=15 mv , gmax = 25 ns , gmid=12gmax , gslope = gmid , vrev=20 mv .
the time - dependent synaptic coupling strength g(t ) is determined by the spike - timing of pre- and postsynaptic spikes .
we consider four types of activity - dependent couplings that have been found in experiments : ( 1 ) an excitatory synapse with continuous stdp ( c - stdp ) .
one ( figure 1(a ) ) is from the recording of the neocortex - layer 5 xenopus tectum hippocampus [ 31 , 35 ] , and the other is from the neocortex - layer 4 spiny stellates .
the latter form will not be considered here , because it introduces persistent decrease to synaptic strength that would result in none synchronization if two neurons have different inherent periods .
( 2 ) an excitatory synapse with discontinuous stdp ( dc - stdp , figure 1(b ) ) [ 17 , 36 ] ; ( 3 ) an excitatory synapse with discontinuous anti - stdp [ 36 , 37 ] ( dc - astdp , figure 1(c ) ) ; ( 4 ) an inhibitory synapse with stdp ( in - stdp , figure 1(d ) ) [ 18 , 19 , 36 ] .
graw is a function of t = tpostspike tprespike , time difference between the times of postsynaptic and presynaptic spikes .
the learning rules corresponding to figures 1(a ) , 1(b ) , 1(c ) , 1(d ) ) are provided as follows
( 8)c - stdp:graw={aplust0tpluset / tplus,t>0,asubt0tsubet / tsub,t0,dc - stdp:graw={apluset / tplus,t>0,asubet / tsub,t0,dc - astdp:graw={apluset / tplus,t>0,asubet / tsub,t0,in - stdp:graw={aplus(et / tplus0.5),t>0,asub(et / tsub0.5),t0 , aplus = asub .
synchronization of pre- and post - synaptic neurons occurs when |t1 t2| is limited in an acceptable range .
although there is some arbitrariness in setting the criteria of synchronization , there is no qualitative change in our results if the criteria change in two folds .
we have observed that simulations from different initial values of v2 , s could result in different outputs , that is , the post - synaptic neuron sometimes synchronizes with the pre - synaptic one , sometimes keep its original period , or sometimes fires with an oscillating period ( see figure 2(c ) ) .
we therefore carry out 40 times of simulations , from randomly selected initial values , for every t2 .
the standard deviation of |t1 t2| , indicating how precisely the neurons are synchronized , represents the quality of synchronization .
range of t2 , in which post - synaptic neuron is successfully entrained by the pre - synaptic neuron , that is , |t1
t2| < 1.5 in all 40 simulations , is defined as the synchronization window .
we investigate the width of synchronization window of various stdp curves , with the same set of parameters . the period of the pre - synaptic neuron is chosen to be 171 milliseconds , which falls into the range of theta waves .
first , it has fairly wide synchronization windows which allow comparisons in a relative precise manner and can provide clearer information about synchronization windows of various stdp learning rules .
second , the slow theta waves always involve many neurons that fire synchronously [ 38 , 39 ] .
also , theta waves have many interesting implications . for example , theta waves are normally absent in healthy awake adults , but appear during the state of meditation . during emotional arousal and various types of rhythmic activities during sleep ,
and it is known that coherent theta activity ( 48 hz ) in amygdala - hippocampal circuits is deeply involved in fear memory . with fixed period of the pre - synaptic neuron t1 , we evaluate the coupled period of postsynaptic neuron t2 when it is driven by the pre - synaptic neuron .
the values of learning parameters used in c - stdp , dc - stdp , dc - astdp are aplus = 9 ns , asub = 6 ns , tplus = 100 milliseconds , tsub = 200 milliseconds , additionally 0 = 30 milliseconds in c - stdp , and in in - stdp are aplus = asub = 8 ns , tplus = 100 milliseconds , tsub = 200 milliseconds . our model and most values of parameters are from the model of nowotny for c - stdp , except aplus , tsyn , vslope , gmax are different .
especially , t1 is fixed at 171 milliseconds in our simulations while t2 is set to constant value 300 milliseconds of nowotny 's work .
the window of synchronization ( upper panel ) and quality ( middle panel ) of dc - stdp are presented in figure 2 as an example .
the upper panel shows the number of synchronization times in 40 simulations , for each t2 .
it is clear that , in certain range of t2 , simulations from different initial values may have different results .
only when t2 falls into the segment from 194 to 221 , the post - synaptic neuron can synchronize with the pre - synaptic neuron from any initial value .
it is easily found that there are some t2 corresponding to the number of synchronization times between 1 and 39 . in this situation ,
we present the three possible states of post - synaptic neuron 's firing in figure 2 ( lower panel)keeping the initial period ( squares ) , oscillating ( circles ) , and synchronizing with the pre - synaptic neuron ( dots ) . obviously , these states are independent of the synchronization criteria we set . for the purpose of discussing the function role of stdp rules in synchronization ,
the synchronization windows of various type of stdp are plotted in figure 3 , in which the case of constant synaptic conductance is also included as a comparative tool .
the same parameter values used in simulations ensure a fair comparison . in our simulation studies ,
we choose the maximal synaptic strength and the middle synaptic strength of stdp synapse as the synaptic strength of constant synapse in this study .
interestingly , because the synchronization windows for stdp rules are narrower than synchronization window for constant synapse g = 25 ns in figure 3 , these results , opposite to previous reports , indicate that all stdp rules do not enhance synchronization comparing with the constant synapse under the chosen parameters .
first , increasing the excitatory constant synaptic connections from 12.5 ns to 25 ns , leads to a wider synchronization window .
second , the widest ranges of synchronization window are achieved by the excitatory constant connection g = 25 ns and c - stdp rules . however , the lower boundary of the synchronization window of c - stdp is much nearer to t1 than that of excitatory constant synapse .
thirdly , although c - stdp and dc - stdp are fitted from the same set of experimental data , c - stdp has a much wider synchronization window than dc - stdp .
we conclude that all stdps do not give rise to enhanced synchronization and the window of dc - stdp is surprisingly narrow under the chosen parameters in figure 3 .
therefore , the questions about what bring about these results inspire us to study further . at the same time ,
figure 2 shows a large part of probabilistic synchronization , whose range is a subset of the synchronization window of constant synaptic connection with g = 25 ns .
we are interested in if the probabilistic synchronization could be enhanced into absolute synchronization by modulation of learning curves .
these are the theme of the next section . in order to establish the functional role of stdp clearly
, we consider if the learning parameters for each stdp rule have important effect on synchronization .
an increase in the degree of synchrony of a uniform input can cause transitions between memorized activity patterns in the order presented during learning .
however , if synchronous input is at a low level , transitions can not occur .
the synchrony - asynchrony transition have also been implemented in controlling winner - take - all competition , the next recalled time of associative memory and the fine structure of cell assemblies . in this section
, we will discuss the flexibility of the synchronization window , by exploring regulation of width of the synchronization window , whose boundary indicates the synchrony - asynchrony transition .
we take the modulation of learning parameters as the method to regulate the synchronization window .
there are four parameters that determine a learning rule aplus , asub , tplus , tsub . with
three of them fixed and only one parameter changing , we could explore its influence on the width of the synchronization window .
for example , aplus increases from an adequately small value 1 ns to 20 ns with a step of 1 ns .
we have also scanned values that are beyond 20 ns , but find that the effect of increasing aplus is saturated around 20 ns . further increasing aplus brings no more effect .
other parameters are fixed as : asub = 6 ns , tplus = 100 milliseconds , tsub = 200 milliseconds , t2 = 233 milliseconds . in these conditions , we present the effect of aplus on the location of the synchronization window with the dc - stdp rule .
figure 4(a ) shows the value of arp ( average change of relative period ratio ) = t2 t2/(t2 t1 ) for different aplus .
some points have value 0 or 1 , which means post - synaptic neuron keeping initial period or achieving synchronization with the pre - synaptic one , respectively .
figure 4(b ) gives an explanation that these points correspond to probabilistic synchronizations with fixed t2 = 233 .
we find that the absolute synchronization range is from 10 ns to 20 ns in figure 4(b ) .
according to the definition of synchronization window of t2 , we can similarly define 10 ns to 20 ns as the synchronization window of aplus , with dc - stdp rule and other fixed parameters .
the boundary of this synchronization window indicates where synchrony - asynchrony transition happens when changing aplus . from the results of figure 4 ,
the reason why synchronization window of constant synapse is wider than that of stdp rules ( figure 3 ) may be explained by learning parameters . to figure out a global picture of the effect of aplus on synchronization for c - stdp rule
aplus increases from 1 ns to 20 ns with a step of 1 ns while other three parameters keep initial values : asub = 6 ns , tplus = 100 milliseconds , tsub = 200 milliseconds .
the points in figure 5(a ) show the synchronization range of aplus with t1 divided by the chosen values of t2 .
the lower boundaries , as well as those upper boundaries that are other than 20 ns , indicate the position of synchrony - asynchrony transitions .
for example , when t2 is 177 milliseconds equivalent to t1/t2 = 0.966 , aplus outside of the points range from 8 ns to 11 ns can not lead to synchronization between the two neurons .
in addition , for those points marked on the horizontal axis , synchronization could not be established no matter what values aplus take . according to this global picture ,
the intersection of those synchronization ranges of aplus , which is from 10 ns to 11 ns , identifies the range of aplus that would lead to the widest synchronization window which is from 177 to 289 .
this optimal synchronization window for c - stdp is wider than constant synapse g = 25 ns .
taking the same method as aplus , we study the effects of other three parameters on synchronization .
figure 5 presents the situation of asub varying from 1 ns to 20 ns with the step 1 ns ( circles , figure 5(a ) ) , tplus ( points , figure 5(b ) ) and tsub ( circles , figure 5(b ) ) both varying from 10 milliseconds to 400 milliseconds with the step 10 milliseconds .
when changing one parameter to explore how the range of synchrony evolves with t2 , other three parameters keep their initial values as in figure 3 . similarly , the global modulation picture of four learning parameters for other learning rules can be got .
the optimal synchronization windows for various learning rules are presented in figure 6 comparing with previous synchronization windows obtained in figure 3 .
the parameters are derived according to regulating one parameter while other three parameters keep initial values . under the optimal parameters , the synchronization windows for stdp rules are not narrower than constant synapse g = 25 ns .
consequently , the reported important role of stdp in synchronization should be dependent on learning parameters . for the first three stdp rules ,
the optimal synchronization windows are got by regulating tsub while other three fixed learning parameters keep initial values . for the last stdp rule ,
, we find that the optimal synchronization windows for c - stdp rule and dc - astdp rule are almost equal , and are wider than constant synapses .
however , comparing with these two rules , the optimal synchronization window for dc - stdp rule is much narrower . for inhibitory stdp ,
the synchronization window is the same as that for constant synapse under connection strength g = 25 ns .
accordingly , what makes the optimal synchronization windows for various stdp rules different deserves an explanation .
we find that the mechanisms of synchronization caused by c - stdp ( or dc - astdp ) and dc - stdp ( or in - stdp ) are different in our model .
figures 7(a ) and 7(b ) show the average t = tpostspike tprespike , and synaptic strength after an episode of coupling time for c - stdp rule .
there are two types of behavior for t when synchronization occurs ( figure 7(a ) ) . in a section of constant t
, the synaptic strength does not achieve the maximal value . apparently , in this situation , postsynaptic neuron achieves synchronization with the pre - synaptic neuron depending on the balance between potentiation and depression of synaptic conductance . in the rest part of synchronization window
it indicates that for larger t2 , postsynaptic neuron achieves synchronization depending on the effect of maximal synaptic conductance . for dc - astdp rule ,
when the post - synaptic neuron synchronizes with the pre - synaptic neuron under small t2 , the change of synaptic potentiation and depression cancel each other .
however , for the small portion of synchronization window at the right side , synaptic conductance gets the maximum at the stationary synchronized state . for dc - stdp and in - stdp rules , the synchronization mechanisms may be different with the above two stdp rules . because the potentiation and depression of synaptic conductance cancel each other
however , for the dc - stdp rule ( figures 7(c ) and 7(d ) ) , t keeps varying which means that the potentiation and depression of synaptic conductance do not cancel each other at the synchronization state .
but , it is easily found that the synaptic conductance is at the stationary maximum for dc - stdp rule .
thus , postsynaptic neuron achieves synchronization completely depending on the effect of the maximal synaptic conductance for dc - stdp rule .
the state of in - stdp rule is similar to dc - stdp rule . as a result
for the few t2 at the right side of the synchronization window , the synaptic conductance achieves the maximum with c - stdp and dc - astdp rules .
because the frequency mismatch is larger , the synapse needs to be stronger to entrain the post - synaptic neuron .
but for most part of synchronization window at the left , c - stdp and dc - astdp rules rely on the balance of potentiation and depression . instead of balancing out potentiation and depression during one cycle
, dc - stdp and in - stdp rules depend on synaptic strength achieving its maximum .
it is important to understand why c - stdp and dc - astdp rely on the balance of potentiation and depression while dc - stdp and in - stdp do not .
have introduced the mechanisms behind the enhancement of neural synchronization by c - stdp rule which rely on the balance of potentiation and depression .
the synapse strength remains stable regardless of postsynaptic neuron firing later or earlier attributed to the specific shape of c - stdp curve .
we adopt the similar analysis method here for the dc - astdp and dc - stdp .
the time lags are recorded as t1 and t2 , where t1 t2 = t1 = t2 and g1 g2 = 0 ( figure 8) at this state .
synaptic strength will be depressed , due to g1 g2 < 0 for dc - astdp rule , so that the post - synaptic neuron is less excited and goes back into the synchronized state ( figure 8(b ) ) .
but for dc - stdp , when post - synaptic neuron fires faster , synaptic strength will be increased due to g1 g2 > 0 in this case .
the post - synaptic neuron is more excited and can not go back into the synchronized state ( figure 8(c ) ) .
the opposite direction is the same case for dc - stdp and can not go back into the synchronized state .
therefore , the synchronization mechanisms between these two rules are different . for in - stdp rule
, we can easily find that g1 g2 is always positive , where g1 g2 = aplus ( exp(x / tplus)0.5 ) asub ( exp(x171/tsub ) 0.5 ) and values of parameters are the same as figure 3 .
it means that the potentiation and depression of synaptic conductance during one period can not achieve balance .
the synaptic strength must achieve the maximum resulting from g1 g2 > 0 . on the other hand
we try to explain the role of a learning parameter by considering how it influences the synapse conductance , which is a major factor for synchronizing neurons with a given mismatch of intrinsic frequencies .
it is obvious that if synaptic conductance becomes stronger , it can make larger t2 to achieve the same period with pre - synaptic neuron for various stdp rules .
thus , with other three learning parameters fixed , larger aplus values , which are corresponding to the stronger stable synaptic strength for c - stdp rule , can cause larger t2 synchronization . similarly , smaller asub values will give rise to larger t2 synchronization for c - stdp ( figure 5(a ) )
moreover , from figure 5(b ) , moderate tplus values can also make larger t2 synchronized to t1 because these values bring about stronger synaptic strength .
based on the expression of c - stdp rule in section 2 , let tplus be variable and let other parameters keep constant .
graw is viewed as the function of variable tplus . by calculating the derivative of graw
, we can find that graw is a first increasing and then decreasing function when tplus increases gradually .
thus , medial values of tplus can result in stronger synaptic strength . by the same reasoning for tsub
, we can conclude that smaller or larger tsub can make larger t2 synchronization for c - stdp ( figure 5(b ) ) .
the effects of learning parameters on synchronization about other learning rules are similar to the c - stdp rule for larger t2 .
however , smaller t2 values leading to synchrony are only related to c - stdp and dc - astdp , because they rely on the balance of depression and potentiation which could lead to an appropriate low stable synaptic strength .
therefore , only proper learning parameters got by regulating the effect of learning parameters on synchronization are required for smaller t2 achieved synchronization .
finally , we conclude why the widest synchronization windows for some stdp rules are different . from the above statements
the other is the balance of depression and potentiation which can make smaller and moderate t2 synchronize . for c - stdp and dc - astdp
however , dc- stdp and in- stdp rules , due to their specific shape , can only make use of the first one .
this implies that the widest synchronization windows for dc - stdp and in - stdp rules can not exceed the synchronization windows for the maximum constant connection strength under the same model respectively .
therefore , the optimal synchronization windows for c - stdp and dc - astdp are wider than those for dc - stdp and in - stdp .
inspired by previous experiments and theoretical researches , we study the important aspects of stdp - induced synchronization in this paper , such as the role of various stdp rule in synchronization , the widest synchronization window through regulating learning parameters , and synchronization mechanism . in order to explore the functional role of stdp in synchronization , we compare synchronization windows of different types of stdp rules with that of constant synapse under the same model parameters . for the given parameters ,
synchronized responses have a stronger influence on cells at subsequent processing stages than nonsynchronized responses [ 4850 ] .
and the enhanced precise synchronization is important in improving a rapid and reliable transmission of information about sensory changes [ 2 , 51 ] .
recent researches have reported various methods to enhance synchronization , such as , selective attention and time delay . here , we present the effect of modulation of learning parameters on synchronization and optimal synchronization window which are not narrower than constant synapse .
the optimal synchronization windows by c - stdp and dc - astdp rules are much wider than constant synapse .
it indicates that the function role of stdp rule in synchronization depends on the learning parameters .
the optimal synchronization windows of c - stdp and dc - astdp are wider than that of dc - stdp for excitatory synapse . for c - stdp rule and dc - astdp rule ,
a stationary synchronized state completely depends on the balance between potentiation and depression or the maximal synaptic conductance .
however , for dc - stdp and in - stdp rule , the stable synchronized state depends on the maximal synaptic conductance under the self - limitation of synaptic strength .
if we change the type of bound of synaptic strength for dc - stdp rule from self - limitation to artificial bounds , we find that the synchronization mechanism does not change . in a word ,
on one hand , the synchronization range of dc - astdp and c - stdp can achieve the optimal synchronization window of dc - stdp , depending on the maximal synaptic conductance . on the other hand
, dc - astdp and c - stdp can extend the synchronization windows to include smaller t2 by the balance between potentiation and depression .
for example , neurons in cat area 17 can be grouped in 4 different electrophysiological cell classes , including regular spiking . and spontaneous ,
regular action potentials were observed both with cell - attached patch recordings as well as with whole cell current - clamp recordings for cholinergic neurons in the parabigeminal nucleus of the rat midbrain .
for example , whether pyramidal neurons in different cortical layers exhibit similar tendencies to synchronize is studied .
based on this point and the functional role of stdp in synchronization , we explore the synchronization windows of various stdp rules from the view of neurons ' regular firing .
stdp - mediated synchronization is a remarkably robust phenomenon against strong noise [ 30 , 31 ] .
although our simulation is not under the noise environment , our results may represent some predictions for stdp - mediated synchronization in noisy environment .
in addition , from figure 2(a ) , we can clearly see that some synchronization number is between 1 and 39 .
our results present that the range of t2 values leading to synchrony increases strongly if the constant synaptic connection is increased from 12.5 ns to 25 ns .
find that the extent of synchrony does not change considerably by doubling the synaptic conductance .
furthermore , t1 is fixed at 171 milliseconds in our simulation while t2 is fixed at 300 milliseconds in theirs . when t2 is fixed , the range of t1 values leading to synchrony is limited from 0 to t2 no matter how the strength of constant connection changes .
however , when t1 is fixed , the range of t2 values leading to synchrony can vary from t1 to very large value due to the increase of the constant connection .
at the same time , if we adopt the same parameters with nowotny 's paper , the similar result can be got .
furthermore , when constant synaptic connection is 0 ns , it is clear that two neurons with different initial periods can not synchronize .
along with the increase of strength of constant connection , some t2 must cause the synchronization .
thus , it is easily found that synchronization window must become wider by increasing the constant connection to some degree .
the question of how the time windows of various stdp rules are biophysically regulated remains relatively unexplored .
it has been proposed that conscious perception depends on the transient synchronization of widely distributed neural assemblies . and
long - distance synchronization plays a role in triggering the cognitive processes associated with conscious awareness .
in addition , some diseases and the function of brain are related with synchronization mentioned above , especially in theta ( 48 hz ) rhythm synchronization during fear memory retrieval which is consistent with what we considered here . | we discuss effects of various experimentally supported stdp learning rules on frequency synchronization of two unidirectional coupled neurons systematically .
first , we show that synchronization windows for all stdp rules can not be enhanced compared to constant connection under the same model .
then , we explore the influence of learning parameters on synchronization window and find optimal parameters that lead to the widest window .
our findings indicate that synchronization strongly depends on the specific shape and the parameters of the stdp update rules .
thus , we give some explanations by analyzing the synchronization mechanisms for various stdp rules finally . |
parental diabetes status was determined from a longitudinal study of health conducted within the gila river ( pima ) indian community in which residents 5 years old have been invited for research examinations consisting of the measurement of height and weight and a 75-g oral glucose tolerance test ( ogtt ) approximately every 2 years .
diabetes was diagnosed according to world health organization 1999 criteria ( 7 ) or by review of the medical record if made in a clinical setting .
we defined three groups of offspring according to parental diabetes status : 1 ) offspring of diabetic fathers ( odf ) consisting of subjects whose father developed diabetes at < 35 years of age , but whose mother remained nondiabetic until > 35 years of age ; 2 ) offspring of mothers with early onset of diabetes ( omed ) consisting of subjects whose mother developed diabetes at < 35 years of age , but after the date of birth of the subject documented by a normal ogtt following delivery ( mean sd time between subject 's date of birth and mothers date of diagnosis , 8.9 4.2 years ) , and whose fathers remained nondiabetic until > 35 years of age ; and 3 ) a control group ( con ) consisting of offspring whose parents were known to be nondiabetic until > 50 years of age .
the third group can be considered a control group because of previous evidence that offspring of parents who do not develop diabetes until age > 50 years have a risk for developing diabetes comparable with that of offspring whose parents never developed diabetes ( 8) . for additional characterization of the parents , we determined the diabetic cumulative incidence ( ci ) score of each parent in the sample ( 8) .
briefly , the diabetes score was derived by first calculating the specific cumulative incidence of diabetes as a function of age ( cia ) in the pima population .
if diabetes was present , then the score is calculated by 1 cia at the age of first diagnosis of diabetes .
if diabetes was not present , then score is calculated as 0 cia at the time of the last biennial examination .
the score thus contains information on whether an individual developed diabetes and the age of onset of diabetes and is positive if diabetes was ever present and greater if diabetes developed at an earlier age .
conversely , a negative score is calculated if the individual was nondiabetic at the last biennial examination and is most negative in those who remain nondiabetic into old age .
volunteers also participated in a study of metabolic determinants for the development of type 2 diabetes and obesity . at the time of their participation ,
all subjects were in good health and without evidence of diabetes ( by ogtt ) , as determined by a comprehensive medical evaluation including medical history , physical examination , and routine laboratory testing .
subjects were admitted for 1015 days to the clinical research unit of the national institute of diabetes and digestive and kidney diseases in phoenix , arizona , and were provided a standard weight - maintaining energy needs diet containing 50% of calories as carbohydrate , 30% as fat , and 20% as protein for at least 3 days before metabolic testing .
after at least 3 days , volunteers underwent a 75-g ogtt after a 12-h overnight fast to exclude diabetes .
only subjects who were full - heritage pima indian or related tohono o'odham were included in the analysis .
body composition was measured by dual - energy x - ray absorptiometry using a total body scanner ( dpx - l ; lunar , madison , wi ) .
percentage body fat ( % bf ) , fat mass ( fm ) , and fat - free mass ( ffm ) were calculated as previously described ( 9 ) .
insulin action was assessed at physiological insulin concentrations during the hyperinsulinemic - euglycemic clamp technique ( 10 ) .
briefly , after an overnight fast , a primed ( 30 ci ) continuous ( 0.3 ci / min ) infusion of [ 3-h ] glucose was started to determine endogenous glucose production ( egp ) .
at least 2 h after starting the isotope infusion , a primed continuous intravenous insulin infusion was administered for 100 min at a constant rate of 40 mu / m / min .
blood samples for measurement of [ 3-h ] glucose specific activity were collected at the end of the basal period and every 10 min during the final 40 min of insulin infusion . under basal ( i.e. , fasting ) conditions ,
egp was calculated as the [ 3-h ] glucose infusion rate divided by the steady - state plasma 3-[h ] glucose specific activity .
the rate of total insulin - stimulated glucose disposal was calculated for the last 40 min of the insulin infusion and was corrected for the rate of egp calculated from the steele equation ( 11 ) . individual variation in plasma glucose and insulin concentrations during the clamp
were taken into account in the calculation of insulin action ( m - low ) ( 12 ) .
all measurements derived from the clamp were normalized to estimated metabolic body size ( embs ) , which is directly derived from ffm but takes into account the fact that the intercept of the relationship between ffm and resting metabolic rate is not zero ( 17.7 kg in our laboratory [ i.e. , embs = ffm + 17.7 kg ] ) ( 12 ) .
insulin secretion was measured as the response to a 25-g intravenous glucose tolerance test ( ivgtt ) .
the air was calculated as the average increment in plasma insulin concentration above basal in samples obtained 3 , 4 , and 5 min after the bolus injection of glucose ( 13 ) . at 0730 h
, subjects were fed a mixed - meal breakfast ( consisting of a bacon - and - egg sandwich on toast accompanied by orange juice ) containing 10% of calories from protein , 45% from fat , and 45% from carbohydrates and providing 20% of daily energy requirements for each subject .
the meal was consumed within 15 min , and subjects rested quietly in bed throughout the study .
blood samples for insulin and glucose were drawn before and 30 , 60 , 90 , 120 , 150 , and 180 min after initiation of the meal test .
plasma glucose concentrations were measured by the glucose oxidize method ( beckman instruments , fullerton , ca ) .
plasma insulin concentrations were measured by the herbert modification of the method of yalow and berson ( 14 ) , by an automated auto - analyzer ( icn radiochemicals , costa mesa , ca ) , or by an automated immunoassay ( access , beckman instruments ) .
all studies were approved by the institutional review board of the national institute of diabetes and digestive and kidney disease .
statistical analyses were performed using the procedures of the sas statistical package ( version 8.2 ; sas institute , cary , nc ) .
air and m - low were log10 transformed to normalize their distributions before parametric analyses . unless otherwise specified , all data are expressed as means sd .
general , anthropometric , and metabolic characteristics in table 1 were evaluated using student 's t test , anova , or analyses for continuous and categorical variables , respectively .
since even mild degrees of glucose intolerance can be associated with impairments in insulin secretion ( 15 ) only subjects with normal glucose tolerance were included for further analyses of air .
the glucose and insulin responses during the ogtt , ivgtt , and meal test by group were compared by ancova using the mixed procedure in sas .
the general linear models were used to adjust % bf for age and sex ; m - low ( mg kg estimated metabolic body size ( embs ) min ) for age , sex , and % bf , and air for age , sex , % bf , and m - low ( 10 ) .
adjusted least - squares means ( lsmeans ) were used to compare groups by parental diabetes status using post hoc t test , with tukey 's honestly significant difference adjustment for multiple comparisons . for all groups ,
further analyses were conducted and adjusted for the same covariates using general estimating equations to account for family membership .
general , anthropometric , and body composition parameters of subjects according to the age of diabetes onset in the parents * birth weight in odf group available only in seven subjects .
p < 0.05 odf vs. con ( anova ; sex differences analysis ) .
bgo , basal glucose output ; igt , impaired glucose tolerance ; ngt , normal glucose tolerance .
parental diabetes status was determined from a longitudinal study of health conducted within the gila river ( pima ) indian community in which residents 5 years old have been invited for research examinations consisting of the measurement of height and weight and a 75-g oral glucose tolerance test ( ogtt ) approximately every 2 years .
diabetes was diagnosed according to world health organization 1999 criteria ( 7 ) or by review of the medical record if made in a clinical setting .
we defined three groups of offspring according to parental diabetes status : 1 ) offspring of diabetic fathers ( odf ) consisting of subjects whose father developed diabetes at < 35 years of age , but whose mother remained nondiabetic until > 35 years of age ; 2 ) offspring of mothers with early onset of diabetes ( omed ) consisting of subjects whose mother developed diabetes at < 35 years of age , but after the date of birth of the subject documented by a normal ogtt following delivery ( mean sd time between subject 's date of birth and mothers date of diagnosis , 8.9 4.2 years ) , and whose fathers remained nondiabetic until > 35 years of age ; and 3 ) a control group ( con ) consisting of offspring whose parents were known to be nondiabetic until > 50 years of age .
the third group can be considered a control group because of previous evidence that offspring of parents who do not develop diabetes until age > 50 years have a risk for developing diabetes comparable with that of offspring whose parents never developed diabetes ( 8) . for additional characterization of the parents , we determined the diabetic cumulative incidence ( ci ) score of each parent in the sample ( 8) .
briefly , the diabetes score was derived by first calculating the specific cumulative incidence of diabetes as a function of age ( cia ) in the pima population .
if diabetes was present , then the score is calculated by 1 cia at the age of first diagnosis of diabetes .
if diabetes was not present , then score is calculated as 0 cia at the time of the last biennial examination .
the score thus contains information on whether an individual developed diabetes and the age of onset of diabetes and is positive if diabetes was ever present and greater if diabetes developed at an earlier age .
conversely , a negative score is calculated if the individual was nondiabetic at the last biennial examination and is most negative in those who remain nondiabetic into old age .
volunteers also participated in a study of metabolic determinants for the development of type 2 diabetes and obesity . at the time of their participation , all subjects were in good health and without evidence of diabetes ( by ogtt ) , as determined by a comprehensive medical evaluation including medical history , physical examination , and routine laboratory testing .
subjects were admitted for 1015 days to the clinical research unit of the national institute of diabetes and digestive and kidney diseases in phoenix , arizona , and were provided a standard weight - maintaining energy needs diet containing 50% of calories as carbohydrate , 30% as fat , and 20% as protein for at least 3 days before metabolic testing .
after at least 3 days , volunteers underwent a 75-g ogtt after a 12-h overnight fast to exclude diabetes .
only subjects who were full - heritage pima indian or related tohono o'odham were included in the analysis .
body composition was measured by dual - energy x - ray absorptiometry using a total body scanner ( dpx - l ; lunar , madison , wi ) .
percentage body fat ( % bf ) , fat mass ( fm ) , and fat - free mass ( ffm ) were calculated as previously described ( 9 ) .
insulin action was assessed at physiological insulin concentrations during the hyperinsulinemic - euglycemic clamp technique ( 10 ) .
briefly , after an overnight fast , a primed ( 30 ci ) continuous ( 0.3 ci / min ) infusion of [ 3-h ] glucose was started to determine endogenous glucose production ( egp ) .
at least 2 h after starting the isotope infusion , a primed continuous intravenous insulin infusion was administered for 100 min at a constant rate of 40 mu / m / min .
blood samples for measurement of [ 3-h ] glucose specific activity were collected at the end of the basal period and every 10 min during the final 40 min of insulin infusion . under basal ( i.e. , fasting ) conditions ,
egp was calculated as the [ 3-h ] glucose infusion rate divided by the steady - state plasma 3-[h ] glucose specific activity .
the rate of total insulin - stimulated glucose disposal was calculated for the last 40 min of the insulin infusion and was corrected for the rate of egp calculated from the steele equation ( 11 ) . individual variation in plasma glucose and insulin concentrations during the clamp
were taken into account in the calculation of insulin action ( m - low ) ( 12 ) .
all measurements derived from the clamp were normalized to estimated metabolic body size ( embs ) , which is directly derived from ffm but takes into account the fact that the intercept of the relationship between ffm and resting metabolic rate is not zero ( 17.7 kg in our laboratory [ i.e. , embs = ffm + 17.7 kg ] ) ( 12 ) .
insulin secretion was measured as the response to a 25-g intravenous glucose tolerance test ( ivgtt ) .
the air was calculated as the average increment in plasma insulin concentration above basal in samples obtained 3 , 4 , and 5 min after the bolus injection of glucose ( 13 ) .
at 0730 h , subjects were fed a mixed - meal breakfast ( consisting of a bacon - and - egg sandwich on toast accompanied by orange juice ) containing 10% of calories from protein , 45% from fat , and 45% from carbohydrates and providing 20% of daily energy requirements for each subject .
the meal was consumed within 15 min , and subjects rested quietly in bed throughout the study .
blood samples for insulin and glucose were drawn before and 30 , 60 , 90 , 120 , 150 , and 180 min after initiation of the meal test .
plasma glucose concentrations were measured by the glucose oxidize method ( beckman instruments , fullerton , ca ) .
plasma insulin concentrations were measured by the herbert modification of the method of yalow and berson ( 14 ) , by an automated auto - analyzer ( icn radiochemicals , costa mesa , ca ) , or by an automated immunoassay ( access , beckman instruments ) .
all studies were approved by the institutional review board of the national institute of diabetes and digestive and kidney disease .
statistical analyses were performed using the procedures of the sas statistical package ( version 8.2 ; sas institute , cary , nc ) .
air and m - low were log10 transformed to normalize their distributions before parametric analyses . unless otherwise specified , all data are expressed as means sd .
general , anthropometric , and metabolic characteristics in table 1 were evaluated using student 's t test , anova , or analyses for continuous and categorical variables , respectively . since even mild degrees of glucose intolerance can be associated with impairments in insulin secretion ( 15 ) only subjects with normal glucose tolerance were included for further analyses of air .
the glucose and insulin responses during the ogtt , ivgtt , and meal test by group were compared by ancova using the mixed procedure in sas .
the general linear models were used to adjust % bf for age and sex ; m - low ( mg kg estimated metabolic body size ( embs ) min ) for age , sex , and % bf , and air for age , sex , % bf , and m - low ( 10 ) . adjusted least - squares means ( lsmeans ) were used to compare groups by parental diabetes status using post hoc t test , with tukey 's honestly significant difference adjustment for multiple comparisons . for all groups , further analyses were conducted and adjusted for the same covariates using general estimating equations to account for family membership .
general , anthropometric , and body composition parameters of subjects according to the age of diabetes onset in the parents * birth weight in odf group available only in seven subjects .
p < 0.05 odf vs. con ( anova ; sex differences analysis ) .
bgo , basal glucose output ; igt , impaired glucose tolerance ; ngt , normal glucose tolerance .
general , anthropometric , and metabolic characteristics of the study population are shown in table 1 .
we found 10 odf ; 8 of 10 fathers from the odf group had diabetes preconception , and 2 fathers had diagnoses of diabetes 3 and 4 years after the offspring birth .
onset age of diabetes for fathers was lower in the odf group than for mothers in the omed group ( 26.6 4.2 vs. 30.4 3.0 years , p = 0.02 ) .
this slight difference in age was due to exclusion of mothers in the omed group who did not have a nondiabetic ogtt following childbirth .
consistent with this age difference , fathers ' ci score in the odf group was higher than mothers ' ci score in the omed group ( p = 0.04 , table 1 ) .
there was no significant difference between mothers ci score in the odf group and fathers ci score in the omed group , indicating no difference in relative age of onset of diabetes in the opposite parent .
the ci score was comparable between mothers and fathers in the con group ( table 1 ) .
the birth weight and height was not different among the three groups ( table 1 ) .
after adjustment for age and sex , % bf remained lower in the odf group than in the con group ( lsmeans [ 95% ci ] : 27.3% [ 23.331.3 ] in odf vs. 35.4% [ 32.238.5 ] in con and 32.4% [ 28.836.1 ] in omed , p = 0.04 ) .
the ffm , adjusted for age and sex , tended to be lower in odf in comparison to con and omed , but did not reach statistical significance ( 57.9 kg [ 50.465.3 ] in odf vs. 65.8 kg [ 60.071.7 ] in con , and 67.2 kg [ 60.474.1 ] in omed , p = 0.1 ) .
odfs had lower fasting glucose , but 2-h plasma glucose concentrations were comparable with those of cons or omeds ( p = 0.01 and p = 0.1 , respectively , anova ; table 1 ) . despite similar fasting plasma insulin concentrations and glucose responses during the ogtt , plasma insulin concentrations at 30 and 120 min during ogtt ( ins30 , ins120 ) were lower in the odf group than in the con and omed groups ( f = 4.38 , p = 0.02 ; f = 3.81 , p = 0.04 , respectively ; fig .
1 ) . after adjustment for age , sex , 30 min glucose concentration , and m - low , only ins30 remained lower in the odf group than in both the con and omed groups ( lsmeans [ 95% ci ] : 722 pmol / l [ 1321,582 ] in odf vs. 2,699
plasma glucose and insulin concentrations during ogtt ( a and b ) , during ivgtt ( c and d ) , and during meal test ( e and f ) in odf , con , and omed . statistical significance as revealed by two - way anova for the time and group factors and their interactions ( time group ) .
ogtt : post hoc tests for significant differences in time versus group interactions ( effect of time [ p < 0.0001 for all models ] ) ; effect of group ( glucose p = 0.02 , insulin p = 0.001 ) ; effect of time groups interaction ( glucose p = 0.3 , insulin p = 0.1 ) .
ivgtt : post hoc tests for significant differences in time versus group interactions ( effect of time [ p < 0.0001 for all models ] ) ; effect of group ( glucose p = 0.02 , insulin p < 0.0001 ) ; effect of time groups interaction , ( glucose p = 0.3 , insulin p < 0.0001 ) .
ivgtt data available only in six subjects in the odf , six in the con , and seven in the omed group .
meal test : post hoc tests for significant differences in time versus group interactions ( effect of time [ p < 0.0001 for all models ] ) ; effect of group ( glucose p = 0.2 , insulin p < 0.0001 ) ; effect of time groups interaction ( glucose p = 0.3 , insulin p = 0.002 ) .
meal test data available only in six subjects in the odf , eight in the con , and eleven in the omed group .
intravenous glucose administration resulted in a comparable increase in plasma glucose levels in all three groups .
the insulin responses were significantly lower in odf than in con subjects ( effect of diagnosis time p < 0.0001 ; anova ; fig .
1 ) . in addition , log - transformed air was lower in the odf group than the con group ( table 1 ) , and it remained significant after adjustment for age , sex , % bf , and m - low ( lsmeans [ 95% ci ] : 2.08 pmol / l ( 1.962.20 ) in odf vs. 2.55 pmol [ 2.242.75 ] in con and 2.40
pmol / l [ 2.132.55 ] in omed , p < 0.05 ) . during the meal test
the insulin responses during the meal test were significantly lower in odf than in con subjects ( effect of diagnosis time sex p = 0.02 ; fig .
plasma insulin concentrations at 30 min of the meal test were slightly lower in the odf group compared to both the con and omed groups , but it did not reach statistical significance prior to adjustment ( 1,084 462 pmol / l in odf vs. 2090 1,081
1 ) , or following adjustment for age , sex , 30-min plasma glucose concentration , and m - low ( lsmeans [ 95% ci ] : 1,422 pmol / l [ 4892,355 ] in odf vs. 2,087 pmol / l ( 1,3722,803 ) in con and 1,492 pmol / l [ 1,0591924 ] in omed , p = 0.1 ) .
odfs were on average leaner ( having a lower % bf ) ; therefore the mean log transformed m - lows were higher in the odf group than in the con and omed groups ( table 1 ) , but after adjustment for age , sex , and % bf , m - lows were comparable in all three groups ( lsmeans [ 95% ci ] : 2.68 [ 1.803.55 ] mg kg embs min in odf vs. 2.34 [ 1.732.96 ] mg kg embs min in con , 2.28 [ 1.872.68 ] mg kg embs min in omed , p = 0.4 ) .
our analyses indicate that adult nondiabetic offspring of fathers with early onset of diabetes are leaner than offspring of either mothers with early onset of type 2 diabetes or control subjects ( neither parent developed type 2 diabetes by age 50 years ) .
odfs had lower insulin secretion , demonstrated by multiple tests ( ivgtt , ogtt , and meal test ) , but after adjusting for body size , odfs showed comparable insulin action in vivo .
previous studies have shown that the offspring of individuals with early - onset type 2 diabetes are at increased risk for developing diabetes ( 5,8 ) .
some studies report that the risk associated with maternal and paternal early onset of diabetes is approximately additive ( 16 ) , while others do not ( 17 ) .
the present analysis was undertaken to clarify the separate effects of parental diabetes on the offspring 's phenotype . to our knowledge , this is the first study to show a paternal influence on adult body composition .
while previous studies have shown that offspring of diabetic fathers have lower birth weights ( 3,18 ) , these studies did not explore parameters for body composition at later ages .
the general effect of family history on offspring phenotype has been extensively examined , but attempts to separate different parental effects have been more limited .
lindsay et al . ( 3 ) found that paternal history of diabetes was associated with lower birth weight .
in fact , only those with lbw and paternal history of diabetes had increased diabetes risk , and lbw predicted diabetes risk in the father .
our results are in agreement with a previous study also in pima indians ( 5 ) in which lower air was associated with earlier onset of diabetes in either parent . in that study ,
early onset was defined as age of onset below the median age for the cohort ( age < 41 years for mothers and < 46 years for fathers ) . in those whose mothers developed diabetes at < 35 years of age ( exclusive of exposure to diabetes in pregnancy )
, insulin secretion rate was also lower than in those whose parents developed type 2 diabetes at a later age .
however , it is not clear to what extent differences in glucose tolerance ( i.e. , greater impaired glucose tolerance in group of offspring of the mothers with early onset of type 2 diabetes ) may have affected these results .
our results extend and add to these findings as we are able to demonstrate in different tests ( ivgtt , ogtt , and meal tests ) done on different days a consistently lower air . during the ogtt , the 30-min insulin remained lower in odf compared to both omed and con , even after adjustment for age , sex , 30-min glucose , and m - low . in contrast , the 120-min insulin was no longer significantly lower after the same adjustments .
these results indicate that the primary effect of early paternal diabetes is on early insulin secretion , rather than insulin action .
this is supported by the relatively lower fasting plasma glucose in odfs and the lack of a difference in m - low after adjustment for body size .
imprinting is the expression of only a single copy of a gene depending on parent - of - origin and is commonly found in genes that affect fetal growth .
there are at least two distinct mechanisms through which epigenetic information can be inherited : dna methylation ( commonly associated with gene silencing and a contributor to x chromosomal inactivation ) and histone modification ( 19 ) .
numerous genes have been found to be imprinted , and some of them are also involved in longitudinal and skeletal growth and may also be involved in organ growth ( 20 ) .
notable among them are genes such as igf-2 , a growth hormone signaling gene ( 21 ) . in the human liver , the major production source of circulating igf-2 , the igf-2 gene is maternally imprinted during fetal life , whereas postnatally igf-2 is primarily transcribed from the p1 promoter , which is biallelically active in the liver . in other adult tissue ( including the pancreas ) , igf-2 is mainly transcribed from the paternally active promoters ( 22 ) .
animal studies have demonstrated that genes involved directly in pancreatic -cell development might be imprinted , e.g. , the gene for insulin receptor subunit sur1 ( 6,21 ) .
another study demonstrates that genes essential to pancreatic development , such as pancreatic homeobox transcription factor-1 ( pdx-1 ) are susceptible to epigenetic modifications ( 23 ) . in humans
, an independent association between paternal insulin resistance and cord insulin concentrations ( 24 ) also indicates indirect evidence of imprinting .
genes related to adipocyte development , specifically preadipocyte factor 1 ( pref1 ) , necdin , and paternally expressed gene 1 ( peg1 ) can be imprinted ( 6 ) .
pref1 ( an inhibitor of adipogenesis ) is expressed from the paternally inherited chromosome , and imprinting of pref1 is under complex control by both maternal and paternal alleles ( 6 ) .
although a study in mice overexpressing pref1 showed reduced fat content ( 25 ) , additional studies are required to elucidate the potential role of epigenetic effects in adipose tissue development in humans . because of our stringent group criteria , our sample size is small . however , our findings of a leaner phenotype in the odf group are robust and consistent with the previous findings of lbw in this group .
our results could have been affected by the fact that these individuals were studied in adulthood , and so any individuals who developed type 2 diabetes prior to age 18 years were excluded .
however , this would have , if anything , reduced our power to see group differences , particularly in an important diabetes risk factor such as air .
although the age of onset of diabetes in the parents was quite young , there was a slight ( 3.8 4.0 years ) but statistically significant difference in the age of onset of diabetes in parents of the odf versus omed group .
however , the air in odf was markedly lower across different tests on different days , implying that the paternal effect was more important than this relatively small difference in age of diagnosis . in conclusion ,
the results of the present analyses indicate that offspring of fathers with early - onset diabetes are leaner and have lower early insulin secretion compared to individuals in whom both parents remained without diabetes up to 50 years of age .
insulin action , after adjustment for body size , was comparable in all three groups of offspring .
these findings indicate an important role of paternal heritability in body composition and -cell dysfunction .
paternal transmission patterns for susceptibility to diabetes indicate that epigenetic mechanisms are involved in the predisposition to diabetes . whether epigenetic markers are associated with parent - of - origin effects needs further investigation . | objectivepaternal and maternal type 2 diabetes , exclusive of gestational diabetes , may influence risk factors in the offspring differently ( through possible epigenetic effects of parental diabetes ) and are difficult to identify without accurate dates of diagnosis . we aimed to examine a metabolic phenotype in three different groups of offspring to see distinct paternal versus maternal effects.research design and methodswe examined body composition and insulin action ( m ) in nondiabetic subjects and insulin secretion tested via acute insulin response ( air ) in normal glucose - tolerant full - heritage pima indian adults categorized by disparate parental diabetes status : 1 ) offspring of fathers with early - onset diabetes ( age < 35 years ) and nondiabetic mothers ( odf ; n = 10 ) , 2 ) offspring of mothers with early - onset diabetes ( age < 35 years ) , not exposed to diabetes in utero with nondiabetic fathers ( omed ; n = 11 ) , and 3 ) a control group of offspring of parents without diabetes until > 50 years of age ( con ; n = 15).resultsodfs were leaner than cons and omeds ( percent of body fat [ % bf ] : least - squares means adjusted for age and sex [ 95% ci ] : 27.3 [ 23.331.3 ] in odfs vs. 35.4 [ 32.238.5 ] in cons and 32.4 [ 28.836.1 ] in omeds , p = 0.04 ) .
odfs were more insulin sensitive ( had a higher m ) than omeds or cons , but not after adjustment for age , sex , and % bf .
air adjusted for m , age , sex , and % bf was lower in odfs versus cons and omeds ( p < 0.05).conclusionsadult odfs were leaner and had lower early insulin secretion , despite being equally insulin sensitive after adjustment for body fat compared to the other groups , indicating a paternal imprinted effect . |
cerebrospinal fluid ( csf ) leakage is a potential complication of cranial and spinal surgery11 ) .
duraseal ( covidien , waltham , ma , usa ) is a synthetic product which has been increasingly used to facilitate watertight repair of dural defects after cranial and spinal surgery .
the duraseal has been demonstrated to be both safe and effective in clinical studies2,4,7,10 ) and was approved in 2005 by the food and drug administration ( fda ) .
the authors report a patient who developed cord compression following the use of duraseal in cervical spine surgery in which the expansion of the duraseal was believed to be the causative factor .
a 59-year - old man presented to the outpatient department with a 2-year history of progressive leg numbness .
mri ( magnetic resonance image ) had shown intradural mass broad - based on the left side of the dura that compresses the cord severely , displacing it to the right posterior aspect at c7 level ( fig .
1 ) . opening the lamina and dura at c7 level , the mass removal was performed .
the mass was totally removed and the histopathologic findings of frozen biopsy were consistent with those of a meningioma . when repairing dura , duraseal was applied to dural surface that was incompletely approximated with sutures .
eight hours after surgery , the patient developed left - side weakness to motor grade i. a mri scan was urgently performed , which demonstrated a large extradural mass which was causing severe cord compression at the level of tumor removal ( fig .
on reoperating wound , a thick layer of gelatinous material consistent with duraseal was initially encountered .
also the minimal amount of surgicel was removed , which was separate and not interfering with the duraseal. after surgery the patient is showing slightly improvement with his power increasing to motor grade ii .
leakage of csf can lead to delayed healing of surrounding tissues such as skin , muscle , and bone due to its caustic effect11 ) .
the aim therefore once a csf leak is identified , is to stem the leak .
hydrogel sealant ( duraseal ) is a synthetic sealant approved by the fda , which has been increasingly used to facilitate watertight repair of dural defects after cranial and spinal surgery , and has been demonstrated to be both safe and effective in clinical studies2,4,7,10 ) .
duraseal is a self - polymerizing agent which rapidly forms a firm , watertight hydrogel layer within several seconds of application over the dural surface . in comparison to fibrin glue
the firm layer is robust enough to withstand irrigation and gentle suction maneuvers without threat of dislodgement .
these properties are advantageous in affecting a watertight barrier to minimize the risk of csf leakage8 ) .
reported no evidence of postapplication csf leaks or adverse events in 46 patients who had a spontaneous dural tear treated with duraseal2 ) .
cosgrove et al . reported similar findings with no evidence of postapplication csf leaks in 95.5% of patients and no adverse events with the use of duraseal4 ) .
after these reports , the use of duraseal was extended as an adjunct to suture closure of an iatrogenic dural tear .
duraseal is believed to be an ideal sealant for spine procedures because it is a nontoxic bioabsorbable synthetic hydrogel composed of 90% water with similar properties to tissue2,9 ) .
however , one of the drawbacks of using duraseal is its potential to swell up to 50% and slow absorption rate . according to the manufacturers ( covidien , waltham , ma , usa ) , product application to " confined bony structures where nerves are present is contraindicated . "
a study in dog models has demonstrated that hydrogel shows in vivo expansion , and mass effect within the first 2 weeks , after insertion characterized by computerized tomography ( ct ) and mri imaging6,11 ) .
the first reported complication of duraseal was reported when used as a dural sealant after a posterior fossa decompression for a chiari malformation1 ) . a 13-year - old girl developed a worsening quadriparesis after the mass effect of hydrdogel sealant on the cervicomedullary region following foramen magnum decompression .
a case of cervical cord compression has also been reported in a patient who underwent a c5-c6 anterior cervical decompression and fusion who sustained a csf leak when excising the posterior longitudinal ligament with duraseal being used as the primary sealant11 ) .
three hours postoperatively , the patient developed progressive upper and lower extremity motor weakness . during emergent exploration and decompression ,
the surgeons determined the expanded hydrogel was the cause of the compression . also a case has been reported of duraseal causing cauda equina compression after a patient underwent a lumbar laminotomy and discectomy complicated by a dural tear9 ) .
this patient 's dural tear was treated with duraseal and the patient developed symptoms of cauda equina compression 9 days postoperatively .
the patient was taken emergently to the operating room and during exploration and decompression , a large amount of blue duraseal was visualized .
the volume of duraseal removed was measured as 10ml , which is more than three times the amount used primarily , suggesting considerable hydrogel expansion after implantation .
duraseal has now been approved for spinal usage by the fda . to date , the time profile and radiographic appearances of this dural sealant has previously only been systematically characterized in a dog craniotomy model6,8 ) . in a dog model ,
duraseal 's volume expansion was reported to peak between day 3 and 2 weeks after implantation6,9 ) .
to avoid such a complication , we would recommend judicious application of the duraseal with thin - layer application to the defective area only .
we would also caution against applying duraseal in a manners such that it extends over and beyond the bone edges bordering the dural surface after bony decompression .
our case demonstrates the use of duraseal over a site of a dural repair is associated with the risk of developing postoperative cord compression as a result of swelling of the duraseal. duraseal tendency to expand is documented both in the instructions for its use and published case reports , and this is also confirmed by our experience .
a very thin layer of duraseal should be delivered over the site of dural repair and the possibility of postoperative expansion of it should be recognized by the surgeon . | cerebrospinal fluid ( csf ) leakage is a potential complication of cranial and spinal surgery .
postoperative csf leakage can induce delayed healing , wound infection and meningitis .
duraseal ( covidien , waltham , ma , usa ) is a synthetic product which has been increasingly used to facilitate watertight repair of dural defects after cranial and spinal surgery . despite some advantages of duraseal ,
the authors report a patient who developed cord compression following the use of duraseal in cervical spine surgery in which the expansion of the duraseal was believed to be the causative factor . |
being retrospective in nature , the ethics committee approval for this study was not sought , as per institutional policy .
however , all the procedures followed were in accordance with the helsinki declaration of 1975 , as revised in 2000 . only eyes with cnv secondary to pathological myopia , defined as an eye with a minimum refractive error of 6 diopters , were included .
evaluation of the patients included recording the best corrected visual acuity ( bcva ) , fundus photography , digital fluorescein angiography , using the visupac system and the ff 450 fundus camera ( carl zeiss meditec ag gschwitzer strae 51 - 52 d-07745 jena , germany ) , and a macular scan with optical coherence tomography ( oct ) using stratus oct 3.0 ( carl zeiss meditec ag goschwitzer strae 51 - 52 d-07745 jena , germany ) .
treatment was administered only if there was evidence of active cnv , that is , presence of leakage on fluorescein angiography and intra - retinal or sub - retinal fluid on oct .
eleven eyes underwent pdt as per tap protocol { treatment of age - related macular degeneration with photodynamic therapy ( tap ) study } [ group 1 , fig .
three eyes were treated with a combination of pdt and ivta [ group 2 , fig . 2 ] .
twelve eyes were treated with a combination of pdt and intravitreal anti - vegf agents ( bevacizumab 1.25 mg/0.05 ml , fig . 3 or ranibizumab 0.5 mg/0.05 ml , fig .
4 ) administered within 48 72 hours of pdt ( group 3 ) . three eyes in group 3 received verteporfin - pdt with reduced - fluence of 25 j / cm followed by intravitreal ranibizumab ( 0.5 mg/0.05 ml ) within 48 - 72 hours [ fig .
follow - up examinations were performed at two - month intervals after the first visit , and at monthly intervals , thereafter .
the wilcoxon signed ranks test was used to evaluate the difference between pre- and post - treatment visual acuity .
top ( left to right ) : pretreatment color fundus photograph , fluorescein angiography ( early and late phases ) showing active leakage and optical coherence tomography revealing increased retinal thickness in a case in group 1 ( photodynamic monotherapy ) .
bottom ( left to right ) : post - treatment color fundus photograph , fluorescein angiography ( early and late phases ) showing resolution of the leakage with staining of the scar and optical coherence tomography showing a hyper - reflective scar with resolution of fluid in the same case as above top ( left to right ) : pretreatment color fundus photograph , fluorescein angiography ( early and late phases ) showing active leakage and optical coherence tomography revealing increased retinal thickness in a case in group 2 ( photodynamic therapy + triamcinolone acetonide ) .
bottom ( left to right ) : post - treatment color fundus photograph , fluorescein angiography ( early and late phases ) showing resolution of the leakage with staining of the scar and optical coherence tomography showing a hyper - reflective scar with resolution of fluid in the same case mentioned above top ( left to right ) : pretreatment color fundus photograph , fluorescein angiography ( early and late phases ) showing active leakage and optical coherence tomography revealing increased retinal thickness in a case in group 3 ( photodynamic therapy and intravitreal bevacizumab ) . bottom ( left to right ) : post - treatment color fundus photograph , fluorescein angiography ( early and late phases ) showing resolution of the leakage with staining of the scar and optical coherence tomography showing a hyper - reflective scar with resolution of fluid in the same case mentioned above top ( left to right ) : pretreatment color fundus photograph , fluorescein angiography ( early and late phases ) showing active leakage and optical coherence tomography revealing
increased retinal thickness in a case in group 4 ( combination photodynamic therapy and intravitreal ranibizumab ) . bottom ( left to right ) : post - treatment color fundus photograph , fluorescein angiography ( early and late phases ) shows resolution of the leakage with staining of the scar and optical coherence tomography showing a hyper - reflective scar with resolution of fluid in the same case mentioned above top ( left to right ) : pretreatment color fundus photograph , fluorescein angiography ( early and late phases ) showing active leakage and optical coherence tomography revealing increased retinal thickness in a case in group 5 ( reduced - fluence photodynamic therapy with ranibizumab ) .
bottom ( left to right ) : post - treatment color fundus photograph , fluorescein angiography ( early and late phases ) showing resolution of the leakage with staining of the scar and optical coherence tomography showing a hyper - reflective scar with resolution of fluid in the same case mentioned above
the clinical profiles , visual outcomes , and follow - up of different groups are summarized in table 1 .
all groups were statistically comparable in terms of age , presenting bcva , greatest linear diameter ( gld ) , and refractive error ( kruskal - wallis test ) .
visual improvement , defined as any improvement of 0.2 logmar , was seen in five ( n = 11 ) eyes in group 1 , two ( n = 3 ) eyes in group 2 , and eleven ( n = 12 ) eyes in group 3 [ fig . 6 ] .
no correlation between age at onset and final visual acuity was seen in any group . at the last follow - up ,
no ocular or systemic adverse reaction was noted in any of the treated eyes till the last follow - up .
pretreatment clinical features and visual outcomes of different groups bar diagram shows a comparison of pretreatment and post - treatment visual acuities in all the five groups
this study reveals better visual outcomes and reduced retreatment rates in eyes treated with combination pdt and anti - vegf agents . for such eyes
treated with pdt alone , the vip study demonstrated no statistical treatment benefit at the end of two years .
krebs et al , reported that following pdt , the distance visual acuity improved from 43 letters to 53 letters at one year , and was stable thereafter up to three years . a better visual outcome as compared to the vip study was attributed to fewer numbers of retreatments , as repeated treatments with pdt were associated with hypoxic stress and release of vegf .
better visual outcome in our study was again attributable to the same reason . in group 1 , even though the retreatment rate was 0.16 , the degree of visual improvement was less than expected because lacquer cracks were noted to be extending under the fovea in four of these 11 eyes [ fig . 7 ] .
( a ) pretreatment fluorescein angiography ( arteriovenous phase ) showing classic choroidal neovascularization ( arrow - head ) with lacquer cracks ( arrows ) in a case in group 1 ( photodynamic monotherapy ) .
( b ) six months post - treatment fluorescein angiography ( arteriovenous phase ) showing complete regression of choroidal neovascularization , with extension of lacquer cracks under the fovea ( arrow ) montero et al , stated that as the complications with intravitreal triamcinolone were greater in younger individuals , the combination of pdt and ivta should be reserved for the elderly who show a poorer response to pdt and have a lower visual acuity , or for patients with recurrent cnvs .
treatment results for group 2 in our study also reiterate the fact that this modality does not result in a significantly better visual outcome compared to pdt monotherapy .
this study is the first of its kind in analyzing the treatment outcomes of combination pdt with ranibizumab / bevacizumab , for the treatment of myopic cnv .
both combinations are effective in both older and younger age groups with far lesser complications .
the average number of treatments in both groups per month can be translated to 0.18 and 0.16 , respectively , which is less as compared to those reported in the published studies on bevacizumab monotherapy .
the combined regime is postulated to have a beneficial synergistic effect that can reduce the need for repeated injections .
selectivity of verteporfin - pdt has been achieved with reduced light dosage that not only causes reduced choroidal occlusion , but also avoids collateral alteration of the physiological choroid and obtains complete cnv closure .
our results with reduced fluence pdt and intravitreal ranibizumab show that the average number of injections required to cause complete cnv regression was 1.33 at 296 days of follow - up .
however , the average number of injections required with standard fluence pdt and ranibizumab in our study was two , thus validating the above claim , in principle .
, a combination therapy of pdt with anti - vegf agents appears efficacious in the treatment of eyes with cnv secondary to pathological myopia , and may afford better visual outcomes as compared to pdt monotherapy .
however , a larger study with a longer follow - up is required to validate these results . | this retrospective , interventional case series analyses treatment outcomes in eyes with choroidal neovascularization ( cnv ) secondary to pathological myopia , managed with photodynamic therapy , ( pdt ) , ( group 1 , n = 11 ) , pdt and intravitreal triamcinolone acetonide ( 4 mg/0.1ml ) ( group 2 , n = 3 ) , pdt and intravitreal anti - vascular endothelial growth factor ( anti - vegf ) bevacizumab 1.25 mg/0.05 ml , ranibizumab 0.5 mg/0.05 ml and reduced - fluence pdt and intravitreal ranibizumab 0.5 mg/0.05 ml ( group 3 , n=12 ) . all the patients underwent pdt .
intravitreal injections were repeated as required .
spss 14 software was used to evaluate the data .
wilcoxon signed ranks test was used to evaluate pre- and post - treatment vision .
the kruskal - wallis test was used for comparison between the groups .
all the groups were statistically comparable .
all the eyes showed complete regression of cnv , with a minimum follow - up of six months .
all groups had visual improvement ; significantly in group 3 ( p = 0.003 ) .
combination pdt with anti - vegf agents appeared to be efficacious in eyes with myopic cnv .
however , a larger study with a longer follow - up is required to validate these results . |
aflatoxin contamination of food and feed have gained global significance due to its deleterious effect on human and animal health and its importance in the international trade .
the potential of aflatoxin as a carcinogen , mutagen , teratogen , and immunosuppressive agent is well documented .
the problem of aflatoxin contamination of food and feed has led to the enactment of various legislation . however , meaningful strategies for implementation of this legislation is limited by nonavailability of simple , cost - effective method for screening and detection of aflatoxin under field conditions . keeping in mind the analytical constraints in developing countries ,
a simple - to - operate , rapid , reliable , and cost - effective portable aflatoxin detection kit has been developed .
the important components of the kit include a hand - held uv lamp ( 365 nm , 4 w output ) , a solvent blender ( 12,000 rpm ) for toxin extraction , and adsorbent - coated dip - strips ( polyester film ) for detecting and quantifying aflatoxin .
analysis of variance indicates that there were no significant differences between various batches of dip - strips ( p > 0.05 ) .
the minimum detection limit for aflatoxin b1 was 10 ppb per spot .
the kit may find wide application as a research tool in public health laboratories , environmental monitoring agencies , and in the poultry industry.imagesfigure 1 . | |
strain rate imaging is a spatial derivation of local velocity gradients : sr = error ! , subtracting translational velocities as well as the effects of adjacent segments ( tethering ) and giving information about the rate of regional deformation .
the method has been validated for regional function against wall motion by echocardiography and coronary angiography .
strain rate can be displayed in colour parametric imaging , where orange represents shortening , cyan to blue lengthening ( fig .
1 ) temporal integration of strain rate results in strain , or a direct measurement of regional deformation analogous to motion , and which have been validated against ultrasonomicrometry and mr . by the breaking of velocities down to velocity gradients
, it can be seen that some events are not simultaneous in all part of the ventricle , especially in diastole .
the earliest event in diastole seen by this imaging modality is a protodiastolic lengthening of mid septum , followed by isovolumetric lengthening in the apex and then the early filling phase .
thus , the early filling phase is not the earliest diastolic event seen by this imaging modality . early and late filling phases
are seen as waves of stretching , propagating from the base to the apex of the ventricle ( fig 1 ) , with a measurable propagation velocity .
stretching is equivalent to simultaneous wall thinning due to the incompressibility of heart muscle .
the filling phases may thus be pictured as longitudinal events with simultaneous wall stretching and thinning and hence chamber dilation .
peak strain rate is then an index the rate of local wall thinning , and the annulus velocity is the resultant of both ( fig .
the strain rate propagation velocity in early filling has been shown to be reduced in delayed relaxation as well as being load dependent .
the flow propagation of early filling in normal ventricles has been shown to consist of an early phase of column propagation , followed by a later phase of vortex propagation .
flow propagation have been shown to be reduced in diastolic dysfunction [ 11 - 13 ] .
it is considered relatively load independent , although it has been shown to be chamber diameter dependent and thus influenced by dilation .
top , still frames from systole showing yellow to red colours of negative strain rate ( shortening ) , and early diastole showing blue to cyan colours of positive strain rate ( lengthening ) .
below is shown the resulting m - mode from the same cine - loop of one heart cycle .
the numbers to the left refers to the numbers on the 2d images , and are for orientation only .
systole ( s ) starts more or less simultaneous in all levels of the ventricle , while early filling ( e ) and atrial systole ( a ) can be seen as waves of stretching propagating from the base to the apex .
the principle of propagation velocity measurement as the slope of l/t is shown the ecg is shown at the bottom for reference .
is incompressible , systolic shortening has to be balanced by simultaneous wall thickening , and diastolic stretching by thinning , as shown in the upper panel . as the wall gets thinner by diastolic stretching , the transverse diameter of the left ventricle increases .
as the wall stretching ( and hence thinning ) propagates from the base to the apex , the early filling phase can be illustrated as a sequence as shown in the lower panel .
as strain rate and strain rate propagation are the main indices of myocardial relaxation , they are considered the primary event , and flow propagation the secondary .
the aim of this study was to compare the two measures , to establish the relation between them in normal and moderately reduced function , and to assess the influence of other diastolic measurements on flow propagation .
12 control subjects without any evidence of heart disease and 13 patients with hypertension were examined .
informed consent was obtained , and the investigation conformed with the principles outlined in the declaration of helsinki .
the patients participated in the losartan intervention for endpoint reduction in hypertension ( life ) echo substudy , approved by the national ethical committee .
they were selected to the life study according to presence of ecg criteria for left ventricular hypertrophy , randomised to either losartan or atenolol in a blinded design , and additional antihypertensive medication of other types administered as needed .
acquisition of additional sri , tissue doppler and colour flow data were done during scheduled control according to study protocol after 1 2 years of treatment .
one patient had reduced global ef , moderate left ventricular dilation and reduced flow propagation velocity , but was not excluded in order not to introduce bias .
the patients have preserved systolic function ( apart from the one mentioned ) , moderate hypertrophy , and are significantly older than the controls .
p values for differences hr : heart rate , bp : blood pressure , ef : ejection fraction , ivsd : septum thickness in diastole , lvdd : left ventricular diameter in diastole . a specially programmed system five scanner ( ge vingmed ultrasound , horten , norway ) with a
sri was processed online on the scanner , and cine - loops of all three standard apical planes were recorded and transferred to a pc computer for analysis in a dedicated software .
frame rate was 70 100 fps and offset length ( strain rate sample volume ) 5 7 mm .
linear propagation velocity of strain rate during early diastole ( pvse ) was measured along the front of peak strain rate as shown in fig 1 , in all 6 walls of each ventricle , and averaged for each subject .
peak strain rate during early filling ( sre ) was measured in all 16 standard segments of the left ventricle and averaged for each subject .
standard echocardiographic recordings were acquired during the same examination and transferred to a macintosh computer for off - line analysis in echopac ( ge vingmed ultrasound , horten , norway ) .
ejection fraction ( ef ) was measured by modified biplane simpson 's method in apical 4-chamber and long - axis planes in the octave mode .
intraventricular septum thickness ( ivsd ) and left ventricular internal diameter ( lvidd ) at end diastole were measured in parasternal m - mode .
mitral flow for measurement of deceleration time of early filling ( dec .- t ) , peak transmitral flow velocity ( e ) , peak flow velocity during atrial systole was acquired from a position between the tips of the mitral leaflets .
isovolumic relaxation time ( ivr ) was measured by pulsed doppler in a position between aortic orifice and mitral inflow ; valve click of aortic closure and start of mitral flow was used .
colour m - mode of intraventricular flow was obtained with a pulse repetition frequency of 3 khz , and flow propagation velocity during early filling ( pvfe ) was measured as shown in fig .
as the value of flow propagation depends on the method used : black to colour transition , front of first aliased contour or main vector as shown in fig 4 , all three values was measured for comparison of results and variability .
peak velocity of the mitral annulus during early diastole ( ea ) was measured by pulsed wave tissue doppler at four points of the annulus and averaged for each subject . flow propagation .
the two phases of early filling phase i or column propagation and phase ii or vortex propagation described by steen & steen ( 12 ) are also visible .
high flow velocity propagation of phase i , evidenced by the upright column is seen .
in addition there is very little phase ii propagation , indicating a narrow ventricle during early filling .
bottom : from a patient with slightly dilated lv of 65 mm and ef of 45% .
the main velocity propagation is phase ii , vortex propagation with a low propagation velocity .
flow propagation measurement the slope of the line and thus the value for flow propagation is dependent on the contour chosen .
p - values for differences between patients and controls are two - tailed probabilities by two - tailed student 's t - test .
all significant differences were also significant by wilcoxon 's two - sample rank sum test .
relation between flow propagation velocity ( dependent ) and various variables is by univariate and multiple linear regression .
diastolic measurements of flow , tissue doppler and strain rate are shown in table 2 .
the main finding is that strain rate propagation is reduced , while flow propagation velocity is increased in the patient group , contrary to previous findings .
correspondingly there is a significant negative correlation between the two values : r = -0.57 ( 95% ci -0.23 to -0.79 , p < 0.005 , = -0.54 p < 0.005 ) .
there was a significant negative correlation between strain rate propagation velocity and deceleration time of mitral flow : r = -0.51 , ( -0.15 to -0.75 , p < 0.05 , = -0.48 , p < 0.05 ) .
b ; strain rate propagation vs. deceleration time . as strain rate propagation increases velocity filling time decreased .
bottom , ratio of peak early mitral flow velocity / strain rate propagation ( e / pvse ) vs. flow propagation showing a positive correlation .
the patients show near normal peak mitral flow velocity , near normal , but still reduced e / a ratio compared to controls , and deceleration time of mitral flow velocity and ivr are prolonged in the patient group .
early diastolic annulus velocity and strain rate are reduced in the patient group , showing a moderate diastolic dysfunction .
the ratio of mitral flow and annulus velocity , e / ea was 5,4 in the control group , and 7.4 in the patient group , the difference is significant , but still indicates normal filling pressure in both groups . in univariate linear regression ,
only the correlation between strain rate propagation and flow propagation is significant ( p = 0.003 ) .
no significant relation is found between flow propagation velocity and peak annular early diastolic velocity , left ventricular diastolic diameter , peak early diastolic strain rate , deceleration time of early mitral flow , isovolumic relaxation , hr , ef or age , in either univariate or multivariate analysis .
strain rate propagation velocity is significant in both univariate and multivariate ( p = 0.004 ) analysis .
peak mitral flow velocity is not significant in univariate analysis , only in multivariate ( p = 0.017 ) , showing interaction with strain rate propagation velocity ( significance of the interaction : 0.014 ) .
thus , there is a significant correlation between the ratio : peak early mitral flow velocity / strain rate propagation ( e / pvse ) and flow propagation velocity , pvfe : r = 0.67 , ( 0.37 0.84 , p < 0.001 , = 0.58 , p < 0.002 ) . 95% limits of agreement for strain rate propagation velocity ( bland altman statistics ; average difference 2sd of differences between repeated measurements ) was ( -29.4 ; 32.5 cm / s ) by intraobserver and ( -24.2 ; 36.6 cm / s ) by interobserver study . in the present study ,
strain rate propagation velocity has standard error of the mean of 3.44 in controls , and 2.67 in patients , while flow propagation has standard error of 1.59 and 3.75 respectively .
flow propagation was measured in the same files with an interval of one year , by the same investigator .
the intraobserver limits of agreement were ( -33.3 ; 52.1 cm / s ) , showing a low precision .
the difference between patients and controls , and the negative correlation with strain rate propagation velocity , however , remained significant .
comparison of three methods for measuring flow propagation is summarised in table 3 , showing the front of aliased contour to give the best precision .
comparison of flow propagation velocity measurements by three methods p : significance of the differences between the two groups ( standard deviation in parentheses ) .
r : correlation with strain rate propagation velocity ( 95% confidence intervals in parentheses ) .
diastolic measurements of flow , tissue doppler and strain rate are shown in table 2 .
the main finding is that strain rate propagation is reduced , while flow propagation velocity is increased in the patient group , contrary to previous findings .
correspondingly there is a significant negative correlation between the two values : r = -0.57 ( 95% ci -0.23 to -0.79 , p < 0.005 , = -0.54 p < 0.005 ) .
there was a significant negative correlation between strain rate propagation velocity and deceleration time of mitral flow : r = -0.51 , ( -0.15 to -0.75 , p < 0.05 , = -0.48 , p < 0.05 ) .
b ; strain rate propagation vs. deceleration time . as strain rate propagation increases velocity filling time decreased .
bottom , ratio of peak early mitral flow velocity / strain rate propagation ( e / pvse ) vs. flow propagation showing a positive correlation .
the patients show near normal peak mitral flow velocity , near normal , but still reduced e / a ratio compared to controls , and deceleration time of mitral flow velocity and ivr are prolonged in the patient group .
early diastolic annulus velocity and strain rate are reduced in the patient group , showing a moderate diastolic dysfunction .
the ratio of mitral flow and annulus velocity , e / ea was 5,4 in the control group , and 7.4 in the patient group , the difference is significant , but still indicates normal filling pressure in both groups . in univariate linear regression ,
only the correlation between strain rate propagation and flow propagation is significant ( p = 0.003 ) .
no significant relation is found between flow propagation velocity and peak annular early diastolic velocity , left ventricular diastolic diameter , peak early diastolic strain rate , deceleration time of early mitral flow , isovolumic relaxation , hr , ef or age , in either univariate or multivariate analysis .
strain rate propagation velocity is significant in both univariate and multivariate ( p = 0.004 ) analysis .
peak mitral flow velocity is not significant in univariate analysis , only in multivariate ( p = 0.017 ) , showing interaction with strain rate propagation velocity ( significance of the interaction : 0.014 ) .
thus , there is a significant correlation between the ratio : peak early mitral flow velocity / strain rate propagation ( e / pvse ) and flow propagation velocity , pvfe : r = 0.67 , ( 0.37 0.84 , p < 0.001 , = 0.58 , p < 0.002 ) .
95% limits of agreement for strain rate propagation velocity ( bland altman statistics ; average difference 2sd of differences between repeated measurements ) was ( -29.4 ; 32.5 cm / s ) by intraobserver and ( -24.2 ; 36.6 cm / s ) by interobserver study . in the present study ,
strain rate propagation velocity has standard error of the mean of 3.44 in controls , and 2.67 in patients , while flow propagation has standard error of 1.59 and 3.75 respectively .
flow propagation was measured in the same files with an interval of one year , by the same investigator .
the intraobserver limits of agreement were ( -33.3 ; 52.1 cm / s ) , showing a low precision .
the difference between patients and controls , and the negative correlation with strain rate propagation velocity , however , remained significant .
comparison of three methods for measuring flow propagation is summarised in table 3 , showing the front of aliased contour to give the best precision .
comparison of flow propagation velocity measurements by three methods p : significance of the differences between the two groups ( standard deviation in parentheses ) .
r : correlation with strain rate propagation velocity ( 95% confidence intervals in parentheses ) .
strain rate propagation is a measure of the rate of chamber expansion as illustrated in fig 1 .
deceleration time of early mitral flow is a measure of filling time , and the negative correlation is as expected .
thus , strain rate propagation may be taken as a measure of left ventricular filling dynamics during early diastole .
flow propagation velocity and strain rate propagation velocity are similar in the control group . while strain rate propagation decreases in the patient group , consistent with delayed relaxation ,
this finding is contrary to previous findings [ 11,12,14,19 - 22 ] , and unexpected in view of the reduced strain rate propagation , and the negative correlation between strain rate propagation and flow propagation velocity , is consistent with this finding .
measurements of propagation velocities have a low precision , as shown by the wide limits of agreements , and the variability given in table 3 .
the actual value of flow propagation velocity depends on the method chosen , as shown in table 3 and fig .
, measurements are dependent on scanner settings : black - to - colour transition depends on the level of low velocity rejection , the aliasing contour on pulse repetition frequency .
comparing different studies is therefore difficult , as shown by the variety of normal values given , and also for methodological reasons , flow propagation velocity has limited value as an index of diastolic function . on the other hand ,
the low precision of flow propagation can not explain the significance of the results , as low precision alone will result in random , rather than systematic variation .
previous studies have all shown reduced flow propagation velocity in reduced diastolic function . however , in many of those studies , there was simultaneous left ventricular dilation .
it has been demonstrated that in left ventricular dilation , there is no column propagation , but solely vortex propagation , as the main mechanism for the flow propagation delay . in the present study
, there was no left ventricular dilation ( except in the one patient commented on ) , on the contrary , there was a non - significant trend toward a narrowing of the ventricle due to concentric hypertrophy .
in addition slower strain rate propagation causes the ventricle to remain narrow for a longer time during early filling .
however , also in ordinary ageing and in hypertrophic cardiomyopathy , where no dilation is to be expected , there is found delayed flow propagation .
thus , the characteristics of the patient group itself may be a factor in these results .
-the patient group had delayed relaxation , as evidenced by the prolonged deceleration time and ivr as well as reduced early diastolic mitral annulus velocity by tissue doppler .
the e / a ratio but not the e flow velocity was reduced , but the pattern is more normal than in other studies .
there was a significant difference in e / ea ratio , but it was below the cut off value of 8 in both groups , so there was no indication of pseudonormalised mitral flow , although a difference in filling pressure within the normal range can not be excluded .
the main reason for the high early diastolic flow velocity seems thus to be very moderately reduced diastolic function .
i.e. the interaction with strain rate propagation velocity was shown to be a determining factor by multivariate analysis . a correlation between flow propagation velocity and the ratio of mitral flow velocity and strain rate propagation velocity
; e / pvse , will result in normal flow propagation in normals ( fig 6a ) , increased flow propagation velocity in delayed relaxation with higher e velocity ( 6b ) and reduced flow propagation in delayed relaxation with low e velocity ( 6c ) .
b : prolonged deceleration time , but near normal e velocity and e / a ratio .
c : delayed relaxation with severely prolonged deceleration time , reduced e velocity and e / a ratio .
both in a and c , the flow propagation velocity may match strain rate propagation velocity , if the relation e / pvse holds true .
this , however , means that flow propagation velocity is not a simple index of diastolic function , but rather a composite function of more factors , in addition to a low precision .
the importance of mitral flow velocity in relation to flow propagation have been found also by others the reduced diastolic function in the patient group was due to a combination of age and hypertension with moderate hypertrophy .
this was considered acceptable , in view of the object of the study , the mechanics of filling , not causes of diastolic dysfunction .
the function seems to be similar , irrespective of causes , but it still remains a limitation .
results will have no relevance in dilated ventricles , as they do not concern vortex propagation , nor to regional dysfunction where flow pattern is shown to be more complex due to regional disturbances .
strain rate imaging shows the ventricular deformation during early filling to be a dynamic event that is slowed in subjects with delayed relaxation . the strain rate propagation is the main determinant of the filling rate , and is consistent with filling time .
flow propagation velocity , in this study , was found to be significantly increased in patients with delayed relaxation , and was shown to be dependent on both strain rate propagation and mitral inflow velocity , and is thus not a simple index of diastolic function .
neither strain rate propagation nor flow propagation velocities do at present show the precision necessary for clinical use .
gs recruited the patients to the primary study , and referred them to the ultrasound sub study .
bjrn olstad , of ge vingmed ultrasound , horten , norway , programmed the special software for strain rate analysis . | backgroundstrain rate imaging shows the filling phases of the left ventricle to consist of a wave of myocardial stretching , propagating from base to apex .
the propagation velocity of the strain rate wave is reduced in delayed relaxation .
this study examined the relation between the propagation velocity of strain rate in the myocardium and the propagation velocity of flow during early filling.methods12 normal subjects and 13 patients with treated hypertension and normal systolic function were studied .
patients and controls differed significantly in diastolic early mitral flow measurements , peak early diastolic tissue velocity and peak early diastolic strain rate , showing delayed relaxation in the patient group .
there were no significant differences in ef or diastolic diameter.resultsstrain rate propagation velocity was reduced in the patient group while flow propagation velocity was increased .
there was a negative correlation ( r = -0.57 ) between strain rate propagation and deceleration time of the mitral flow e - wave ( r = -0.51 ) and between strain rate propagation and flow propagation velocity and there was a positive correlation ( r = 0.67 ) between the ratio between peak mitral flow velocity / strain rate propagation velocity and flow propagation velocity.conclusionthe present study shows strain rate propagation to be a measure of filling time , but flow propagation to be a function of both flow velocity and strain rate propagation .
thus flow propagation is not a simple index of diastolic function in delayed relaxation . |
partial edentulism can lead to multiple complications from the functional , biological and esthetic aspects.1,2 after the loss of some natural teeth , the inter- and intra - arch relationships of the remaining dentition might be affected .
the adjacent teeth tend to adapt physiologically to the changes by drifting or tipping toward the resultant space , while the antagonist teeth has the tendency to overerupt.1,2 in addition to limit the space for any future prosthesis , occlusal interferences and disfigurement can be introduced .
subsequently , the rehabilitative treatment will be complicated by including invasive adjunctive therapies such as crown lengthening surgery , elective endodontic treatment , orthodontic movement , and increasing the vertical dimension of occlusion.3 this clinical report demonstrates the application of well - planned rehabilitative treatment and coordinated team work of a patient with extreme features of partial edentulism . due to the complexity of the initial presentation ,
the final treatment was accomplished after series of provisional prostheses in conjunction with crown lengthening surgery . the final treatment involved innovatively designed fixed and removable prostheses that employ the concepts of milled surfaces , telescopic attachments , and strategic implant support .
a 49-year - old partially edentulous male was referred to the prosthodontic clinic for the management of his complex dental status .
his chief complaint was dissatisfaction of his existing dental condition that affected quality of his life .
he requested a predictable treatment to improve his dental function and restore the missing teeth .
1a - d ) , the prominent features were as followed : all the remaining teeth were unopposed and almost contacting the residual ridges ; absence of posterior or anterior teeth support , and no occlusal guidance .
the excessive thickness of the attached gingival band indicated over - eruption of the remaining teeth which might be the cause of the significant disfigurement of the occlusal plane .
the maxilla and the mandible were partially edentulous and classified as kennedy class ii modification 1 .
the remaining maxillary incisors and the left mandibular premolar were extensively carious and deemed non - restorable .
the mandibular left first molar was carious on the mesial surface and required root canal treatment . measuring
the vertical dimensions revealed excessive loss of vertical dimension of occlusion ( vdo ) which was manifested as excessive freeway space ( fws ) ( 6 mm ) ( fig .
the phonetic assessment revealed difficulties in pronouncing the /s/ and /f/ sounds . however , the patient adapted to the missing incisal edges and was able to produce the sound with relative acuity .
the patient was stabilized by extracting the non - restorable teeth and initiating root canal treatment for the mandibular left molar .
oral hygiene measures were demonstrated and emphasized before considering any rehabilitative treatment . after obtaining study models ,
occlusal rims were fabricated to record the centric relation at the restored vdo ( fws = 2 mm ) . with the aid of facebow transfer record ,
the study models were mounted on a semi - adjustable articulator ( artex articulator , jensen dental , north haven , ct , usa ) ( fig .
subsequently , it was possible to assess the potential treatment options closely and any adjunctive procedure required correction of the occlusal plane .
the planned occlusal scheme was unilateral group function with long centric following the principles of biological occlusion described by becker and kaiser.4 the bilateral group function was opted because of the tendency for class ii incisal relationship hindering efficient canine guidance . due to the excessive fws , there was no need to consider further increase in the vdo .
on the basis of the diagnostic wax - up , it was decided to extract the severely over - erupted mandibular left second molar and crown lengthening of all the remaining teeth .
further , the diagnostic wax - up was utilized to determine the location of the implants in the second and fourth quadrant .
the next treatment options were presented :
maxillary rehabilitation with crowns and precision implant - supported removable partial denture ( rpd ) .
mandibular rehabilitation with crowns , fixed partial denture and implant fixed partial denture.extraction of the maxillary teeth and rehabilitation with implant fixed prosthesis .
mandibular rehabilitation with crowns , fixed partial denture and implant fixed partial denture.maxillary and mandibular rpds
maxillary rehabilitation with crowns and precision implant - supported removable partial denture ( rpd ) .
maxillary and mandibular rpds for the maxilla , despite the patient 's preference for the fixed option , he was reluctant to undergo through extensive bone grafting procedure . therefore , the first option was selected . as recommended by several authors ,
strategic freestanding implant placement was considered to modify the kennedy classification.5 - 7 additional advantages included improving of the retention and stability , enhancing of patient comfort , and simplifying of prosthesis design.5,7,8 surgical templates were fabricated to guide the implant placement and the crown lengthening surgery . for the mandible , thee
regular platform implants ( biomet 3i , palm beach gardens , fl , usa ) were inserted in the region of lower right canine , first premolar and first molar .
for the maxilla , to overcome the limitation of compromised bone quantity , single wide platform implant ( southern implants ltd , irene , sa ) was placed posterior to the maxillary sinus with angular orientation ( fig .
3 ) . the angular implant placement allowed engaging of maximal amount of available bone.9 to minimize the impact of poor bone quality , conventional healing period was followed as advised by friberg et al .. 10 the first phase of the rehabilitative treatment involved restoring the vdo , stabilizing the occlusion and improving the esthetics by constructing provisional maxillary cobalt - chromium rpd and mandibular screw - retained metal reinforced composite resin fpd ( fig .
mastication , comfort , phonetics , and esthetics were closely assessed . the second phase of the rehabilitation comprised of preparing the maxillary and mandibular teeth for porcelain fused to metal prostheses . due to the need to rectify the occlusal plane , it was necessary to prepare all the teeth simultaneously .
chair - side provisional prostheses were fabricated ( luxatemp , dmg , hamburg , germany ) and cemented with temporary cement ( tempbond , kerr corporation , orange , ca , usa ) . the maxillary rpd was readapted to fit the provisional prosthesis .
the technician was instructed to follow the diagnostic wax - up closely to correct the occlusal plane . in this phase ,
as described by emtiaz and tarnow,11 a mesh of cobalt - chromium was constructed and veneered with acrylic resin ( sr ivocron , ivoclar vivadent , schaan , liechtenstein ) .
this allowed the major portion of the fitting surface along with all margins to be covered with acrylic resin ( fig .
the mandibular definitive prostheses were cemented with glass ionomer cement ( fuji i , gc corporation , tokyo , japan ) .
the maxillary prosthesis was tried in and cemented temporarily ( tempbond , kerr corporation , orange , ca , usa ) .
any necessary occlusal adjustments were performed on the maxillary provisional prosthesis . from the diagnostic perspective , the maxillary provisional prosthesis allowed more precise assessment of the function , esthetics and phonetics ( fig .
the patient was reviewed weekly for a period of one month and demonstrated high level of oral hygiene .
the final phase of the rehabilitation involved the fabrication of definitive maxillary fixed prosthesis and precision rpd .
since the maxillary provisional prosthesis provided stable occlusion , it was utilized to obtain precise interocclusal record . to enhance the predictability of the laboratory articulation , medium body silicone impression material ( exahiflex , gc corporation , tokyo , japan ) was applied on the occlusal surface and the patient was asked to occlude on the previously achieved occlusion .
for the first quadrant , porcelain fused to metal crowns were fabricated with milled surfaces incorporated on the palatal aspect ( fig .
extra - coronal precision attachment ( bredent ltd , chesterfield , uk ) was incorporated mesial to the maxillary right canine . for the second quadrant ,
telescopic retention mechanism was used.8 common path of insertion and an occlusal convergence angle of 4 degrees were obtained for palatal milled surfaces and the primary telescopic copings with the aid of a milling system attached to a surveyor table ( amanngirrbach ag , bregenz , austria ) .
the merit of applying telescopic attachment is omitting the palatal major connector without compromising the rigidity of the final rpd framework . for the angulated implant ,
another advantage of palatal milled surfaces and telescopic attachments is enhancing the stability and retention by restricting the rpd path of withdrawal and creating friction between the intimately fitting parallel surfaces.8,12 in addition , with well distributed abutments , the occlusal forces are directed axially.12 the maxillary fixed prostheses were tried in and pick - up impression was taken with polyether impression material ( impregum penta soft , 3 m espe , st .
precision cobalt - chromium framework was constructed on the milled surfaces and secondary copings ( fig .
the definitive rpd was designed to mimic the morphology and occlusion of the provisional prosthesis ( fig .
the fixed prostheses and the primary coping were cemented permanently with glass ionomer cement ( fuji i , gc corporation , tokyo , japan ) .
the implant primary coping was fitted and the retaining screw was tightened to 35 ncm .
the telescope fitting surface of the framework and the external surface of the electroformed copings were sandblasted and treated with metal primer ( panavia f alloy primer , kuraray dental , osaka , japan ) .
individually , the electroformed copings were cemented with resin based cement ( panavia f , kuraray dental , osaka , japan ) to the rpd and the excess cement was removed .
the management of the presented case reflects the importance of judicious use of prosthodontic principles and strategic planning in addition to multidisciplinary team work . despite the significant disfigurement of the occlusal plane , optimal and esthetically pleasant occlusion | partial edentulism has multiple implications in relation to function , esthetics and future rehabilitative treatment .
this case report illustrates the management of a patient with extreme consequences of partial edentulism .
the main clinical findings were unopposed remaining teeth , overeruption of the remaining teeth , loss of vertical dimension of occlusion , and significant disfigurement of the occlusal plane . following the diagnostic procedure ,
a well - coordinated prosthodontic treatment involving liaison with other dental disciplines was indicated .
the management involved an innovative combination of fixed and removable prostheses in conjunction with crown lengthening surgery and strategic implant placement .
series of provisional prostheses were applied to facilitate the transition to the final treatment . |
in a phase ii multicenter double - blind study of gadobenate dimeglumine ( gd - bopta ; bracco spa , milan , italy ) , 113 adult patients with known or suspected liver masses were examined . from this group , 31 patients with biopsy proven malignant primary liver tumors ( hepatocellular carcinoma in 29 and cholangiocarcinoma in 2 ) were identified .
there were 8 women and 23 men with a mean age of 59 years ( range 32 to 75 years ) . in 14 patients there was biopsy or imaging evidence of cirrhosis .
based on a reference standard imaging , a total of 71 focal lesions were identified in these patients . the presence and absence of a liver lesion
was confirmed by intra operative ultrasound ( ious ) in 24 patients ( 48 lesions ) , computed tomography during arterial portography ( ctap ) in 4 patients ( 15 lesions ) , and lipiodol ct ( ctlp ) in 3 patients ( 8 lesions ) .
all patients received at least one of these reference standard imaging studies of the liver within 7 days before to 14 days after the mr imaging . in patients with more than one reference standard
a cyst and two focal areas of focal nodular hyperplasia were identified and excluded from further analysis .
gadobenate dimeglumine is an octadentate chelate of gadolinium which may be used as a non - specific contrast agent like the conventional gadolinium agents as well as a liver - specific contrast agent ( 11 ) .
the chemical and pharmacodynamic properties of this contrast agent have been described previously ( 12 - 16 ) . in brief , following rapid ( 2 ml / min ) intravenous injection of the contrast agent , it initially redistributes into the extracellular space and is then largely eliminated by the kidneys .
some 3 - 5% of the injected dose is however taken up by functioning hepatocytes and undergoes biliary excretion . despite the low percentage of hepatobiliary excretion ,
the fraction taken up produces clinically useful hepatic enhancement that increases liver signal - to - noise ratio ( snr ) and liver - to - lesion contrast - to - noise ratio ( cnr ) ( 6 - 8 , 14 ) . peak enhancement of lesion - to - liver contrast occurs between 40 and 120 minutes . since one goal of the clinical trial was to determine optimal dose ,
the contrast agent ( either 0.25 mmol / l or 0.5 mmol / l solution ) was administered intravenously at 10 ml / min immediately after the unenhanced mr examination .
seventeen patients received 0.05 mmol / kg , and 14 patients received 0.10 mmol / kg .
post contrast imaging was performed at two delayed time points in order to determine the optimal imaging period in the hepatocyte phase .
mr imaging was performed at 1.5 tesla with t1-weighted spin echo ( se ) and t1-weighted gradient echo ( gre ) pulse sequences before contrast administration as well as 40 - 80 minutes ( early ) and 90 - 120 minutes ( late ) after contrast administration .
the liver was imaged with 10 - 14 axial 10 mm thick sections with 2 mm gaps ; a matrix size of 140 - 160256 , and a tailored field of view ranging from 285 - 350380 - 400 mm . t1-weighted se sequences utilized a repetition time between 350 - 550 msec and an echo time of 15 msec and 3 - 4 excitations .
the t1-weighted gre images were acquired with a repetition time of 95 - 150 msec , a 4 msec echo time , an 800 flip angle and one excitation during a single breath hold .
three off - site independent reviewers ( a , b , c ) evaluated the mr images separately in a random unpaired fashion that included the pre contrast images and the post contrast images .
each set of mr images was evaluated individually and the number , size , and location by surgical segment of lesions were recorded on liver maps . additionally , each reviewer , using a 5-point scale system , documented the confidence with which a lesion was detected .
a point of 1 indicated that the lesion was definitely present , a point of 2 indicated that a lesion was probably present while a point of 3 indicated an indeterminate lesion .
point of 4 and 5 indicated that a lesion was probably not present or definitely not present respectively .
each reviewer assessed the presence of lesions for each patient at each time point for each sequence .
the total number of lesions as well as their size and location was determined from the reference standard imaging . in a patient with multiple lesions ,
no more than five lesions per patient were assessed in order not to bias the findings toward patients with multiple lesions .
this allowed inclusion of all patients without skewing the data from the patients with many lesions .
a lesion was considered present if the reviewer confidence ranking was either a 1 or 2 point ( definitely or probably present ) .
false positive lesions were defined as lesions reported by the reviewers with a confidence of 1 or 2 with no corresponding lesion by the reference standard .
analysis according to lesion size was performed by dividing the lesions into three groups based on diameter size : 1 cm or less ; between 1 cm to 2 cm ; and greater than 2 cm . the efficacy of gadobenate dimeglumine enhanced mri was evaluated by assessing the change in detection ( relative to the reference standard ) from pre - contrast mri to contrast enhanced mri .
the change in concordance with the reference standard from unenhanced to enhanced mri in the determination of the number of focal liver lesions was tested using a two tailed mcnemars test .
differences in concordance were also studied between concentrations and imaging times using a two tailed mcnemars test . because all patients were selected on the basis of lesion pathology , specificity and accuracy
in a phase ii multicenter double - blind study of gadobenate dimeglumine ( gd - bopta ; bracco spa , milan , italy ) , 113 adult patients with known or suspected liver masses were examined . from this group , 31 patients with biopsy proven malignant primary liver tumors ( hepatocellular carcinoma in 29 and cholangiocarcinoma in 2 ) were identified .
there were 8 women and 23 men with a mean age of 59 years ( range 32 to 75 years ) . in 14 patients there was biopsy or imaging evidence of cirrhosis .
based on a reference standard imaging , a total of 71 focal lesions were identified in these patients . the presence and absence of a liver lesion
was confirmed by intra operative ultrasound ( ious ) in 24 patients ( 48 lesions ) , computed tomography during arterial portography ( ctap ) in 4 patients ( 15 lesions ) , and lipiodol ct ( ctlp ) in 3 patients ( 8 lesions ) .
all patients received at least one of these reference standard imaging studies of the liver within 7 days before to 14 days after the mr imaging . in patients with more than one reference standard
a cyst and two focal areas of focal nodular hyperplasia were identified and excluded from further analysis .
gadobenate dimeglumine is an octadentate chelate of gadolinium which may be used as a non - specific contrast agent like the conventional gadolinium agents as well as a liver - specific contrast agent ( 11 ) .
the chemical and pharmacodynamic properties of this contrast agent have been described previously ( 12 - 16 ) . in brief , following rapid ( 2 ml / min ) intravenous injection of the contrast agent , it initially redistributes into the extracellular space and is then largely eliminated by the kidneys .
some 3 - 5% of the injected dose is however taken up by functioning hepatocytes and undergoes biliary excretion . despite the low percentage of hepatobiliary excretion ,
the fraction taken up produces clinically useful hepatic enhancement that increases liver signal - to - noise ratio ( snr ) and liver - to - lesion contrast - to - noise ratio ( cnr ) ( 6 - 8 , 14 ) .
peak enhancement of lesion - to - liver contrast occurs between 40 and 120 minutes . since one goal of the clinical trial was to determine optimal dose ,
the contrast agent ( either 0.25 mmol / l or 0.5 mmol / l solution ) was administered intravenously at 10 ml / min immediately after the unenhanced mr examination .
seventeen patients received 0.05 mmol / kg , and 14 patients received 0.10 mmol / kg .
post contrast imaging was performed at two delayed time points in order to determine the optimal imaging period in the hepatocyte phase .
mr imaging was performed at 1.5 tesla with t1-weighted spin echo ( se ) and t1-weighted gradient echo ( gre ) pulse sequences before contrast administration as well as 40 - 80 minutes ( early ) and 90 - 120 minutes ( late ) after contrast administration .
the liver was imaged with 10 - 14 axial 10 mm thick sections with 2 mm gaps ; a matrix size of 140 - 160256 , and a tailored field of view ranging from 285 - 350380 - 400 mm .
t1-weighted se sequences utilized a repetition time between 350 - 550 msec and an echo time of 15 msec and 3 - 4 excitations .
the t1-weighted gre images were acquired with a repetition time of 95 - 150 msec , a 4 msec echo time , an 800 flip angle and one excitation during a single breath hold .
three off - site independent reviewers ( a , b , c ) evaluated the mr images separately in a random unpaired fashion that included the pre contrast images and the post contrast images .
each set of mr images was evaluated individually and the number , size , and location by surgical segment of lesions were recorded on liver maps . additionally , each reviewer , using a 5-point scale system , documented the confidence with which a lesion was detected .
a point of 1 indicated that the lesion was definitely present , a point of 2 indicated that a lesion was probably present while a point of 3 indicated an indeterminate lesion .
point of 4 and 5 indicated that a lesion was probably not present or definitely not present respectively .
each reviewer assessed the presence of lesions for each patient at each time point for each sequence .
the total number of lesions as well as their size and location was determined from the reference standard imaging . in a patient with multiple lesions ,
no more than five lesions per patient were assessed in order not to bias the findings toward patients with multiple lesions .
this allowed inclusion of all patients without skewing the data from the patients with many lesions .
a lesion was considered present if the reviewer confidence ranking was either a 1 or 2 point ( definitely or probably present ) .
false positive lesions were defined as lesions reported by the reviewers with a confidence of 1 or 2 with no corresponding lesion by the reference standard .
analysis according to lesion size was performed by dividing the lesions into three groups based on diameter size : 1 cm or less ; between 1 cm to 2 cm ; and greater than 2 cm .
the efficacy of gadobenate dimeglumine enhanced mri was evaluated by assessing the change in detection ( relative to the reference standard ) from pre - contrast mri to contrast enhanced mri .
the change in concordance with the reference standard from unenhanced to enhanced mri in the determination of the number of focal liver lesions was tested using a two tailed mcnemars test .
differences in concordance were also studied between concentrations and imaging times using a two tailed mcnemars test . because all patients were selected on the basis of lesion pathology , specificity and accuracy could not be assessed .
the number of focal liver lesions identified on gd - bopta enhanced mr images exceeded the number identified on unenhanced images ( table 1 ) .
table 1 separates the number of lesions identified by reviewer by time point as well as by imaging sequence . by combining both the t1-weighted gre and t1-weighted se images before and after contrast ( both early and late time points ) for reviewers a ,
b and c , the number of lesions identified increased after contrast administration from 34 to 53 , 37 to 48 , and 43 to 49 , respectively .
there was no significant difference in lesion detection between the two concentrations ( 0.05 mmol / kg and 0.10 mmol / kg ) of contrast administered .
table 1 shows that , in general , more lesions were identified with the t1-weighted gre pulse sequence when compared to the t1-weighted se technique , and more lesions were identified after contrast administration when both imaging techniques were analyzed together .
most lesions were identified on the late imaging time point ( 90 - 120 minutes ) although several more lesions ( total number ) were identified combining both the early and late post - contrast images .
the number of false positive lesions decreased for two of the three reviewers after the administration of gd - bopta ( table 2 ) .
one reviewer detected all of these lesions while the other two reviewers detected 14 out of 15 solitary lesions .
there were 5 patients with 2 lesions ; both lesions were identified only after contrast administration in 4 of the 5 patients . in the remaining patient with two lesions , the second lesion ( 25 mm ) was not identified before or after contrast . in two of these patients gadobenate dimeglumine administration allowed identification of the second lesion while in the other two patients , gd - bopta administration was required for the visualization of both ( fig .
one lesion was identified before and after gadobenate dimeglumine in all of these patients ; however , the second and third lesions were only identified by one of the reviewers in one patient and two reviewers in another patient . in the third patient with three lesions ,
two out of three reviewers detected more lesions after contrast administration in 6 out of these 8 patients ( fig 2 ) . in the remaining two patients , one patient had no additional lesions identified while only 1 out of the 3 reviewers detected more lesions after contrast in the other patient . in 68% of the patients with more than one lesion by reference standard ( 11 of 16 patients ) ,
after contrast administration , smaller lesions were better detected by two of the three reviewers ( table 3 ) . from a total of 29 lesions smaller than 1 cm ,
the number of lesions detected before and after contrast infusion for reviewers a , b , and c where 7 to 21 , 9 to 15 , and 16 to 18 respectively .
this was statistically significant ( p<0.05 ) for only two of the three reviewers ( fig 3 ) . the number of lesions detected for both the 1 - 2 cm and greater than 2 cm group also increased after contrast administration .
this study shows that gadobenate dimeglumine enhanced t1-weighted mr imaging can improve the detection of primary hepatic malignant neoplasms .
our findings confirm prior reports that have noted improvement in lesion - liver contrast on gd - bopta enhanced images .
furthermore , our findings show that the most important benefit is in the detection of small ( less than 1 cm ) tumors .
prior reports have provided conflicting findings on contrast enhanced mr imaging using hepatocyte targeted contrast agents in patients with cirrhosis .
for example , murakami et al . noted that compared to normal liver , patients with cirrhosis had lower hepatic enhancement with mn - dpdp ( 9 ) while manfredi et al
. reported similar enhancement between normal and cirrhotic livers with gadobenate dimeglumine ( 6 ) .
these differences may be due to variations in the severity of cirrhosis in the subject groups or due to differences in pharmacokinetics of the two drugs as gd - bopta also shows non - specific tissue enhancement ( extracellular effect ) in addition to hepatocyte specific liver enhancement .
our results have important implications with respect to imaging technique and the evaluation of patients with primary hepatic neoplasms .
firstly t1-weighted gre techniques were superior compared to se techniques and there was only minimal improvement in the total number of lesions detected when both sequences were used together .
prior studies have in fact reported that quantitative measurement of liver - to - lesion contrast on t1-weighted gre images is superior to that on se images ( 17 ) .
this advantage is most likely related to greater t1-weighting on the gre images due to the availability of shorter tes and to decreased motion - related noise in these breath - hold images .
these images can also be obtained at thinner section ( 8 mm ) with ample coverage to study the entire liver . while use of fatsaturation may also provide additional benefit , this was not studied and requires future attention ( 18 ) . in terms of the optimal imaging window
, it appears there is a favorable distinction between liver and primary malignant hepatic neoplasms at both the early and late time points after gadobenate dimeglumine administration although slightly more total lesions were detected at the late time point ( 90 - 120 minutes after injection ) .
there was no significant difference in lesion detection between the two doses ( 0.05 mmol / kg and 0.10 mmol / kg ) evaluated .
one possible way to image with this agent is to initially perform dynamic imaging immediately following the pre - contrast examination ( not performed in these cases ) and then , if needed , have the patient return at a convenient time between 1 - 2 hours later to have delayed scans performed .
this approach may not only increase the yield in lesion detection in patients with cirrhosis where dynamic scanning is known to be of critical importance , but may also provide important perfusion data for tissue characterization .
moreover , this approach may well be the preferred procedure in patients suspected of harboring liver metastases .
in such patients , dynamic imaging with conventional gadolinium agents does not necessarily improve lesion detectability over unenhanced scans alone ( 19 - 20 ) .
this did not allow determination of accuracy , sensitivity or specificity since there was an unintentional bias as the reviewers expected to identify at least one hepatic mass .
in addition the off - site analysis methodology may also have biased the results against gd - bopta since clinical information may have improved diagnostic performance was not available . furthermore , the presence of cirrhosis was not proven in all subjects ; it is likely that this patient population represented a spectrum of underlying chronic liver disease and extrapolation to a cirrhotic population should be made with caution .
another limitation was that even though histological diagnosis was available for all the patients , not every lesion was sampled .
finally , comparison of this agent to contrast - enhanced helical ct may also be necessary to determine the clinical utility of gadobenate dimeglumine enhanced liver mr imaging .
clinical utility may also be affected by the fact that the t2-weighted images were not utilized for the evaluation of the images .
this methodology was adopted in order to best evaluate the effect of the contrast agent on t1-weighted images . however , in actual practice , patients would not be evaluated without simultaneous review of the t2-weighted images . in conclusion ,
gd - bopta may serve a role as a contrast agent to identify primary malignant hepatic neoplasms with mr imaging . from our
blinded off - site multicenter evaluation , the contrast agent aids in the detection of smaller lesions in a patient group where traditional imaging ( us , ct , mr ) has been limited . | objectiveto investigate the efficacy of gadobenate dimeglumine ( gd - bopta ) enhanced mr imaging for the detection of liver lesions in patients with primary malignant hepatic neoplasms.materials and methodsthirty - one patients with histologically proven primary malignancy of the liver were evaluated before and after administration of gd - bopta at dose 0.05 or 0.10 mmol / kg .
t1-weighted spin echo ( t1w - se ) and gradient echo ( t1w - gre ) images were evaluated for lesion number , location , size and confidence by three off - site independent reviewers and the findings were compared to reference standard imaging ( intraoperative ultrasound , computed tomography during arterial portography or lipiodol computed tomography ) .
results were analyzed for significance using a two - sided mcnemar 's test.resultsmore lesions were identified on gd - bopta enhanced images than on unenhanced images and there was no significant difference in lesion detection between either concentration .
the largest benefit was in detection of lesions under 1 cm in size ( 7 to 21 , 9 to 15 , 16 to 18 for reviewers a , b , c respectively ) . in 68% of the patients with more than one lesion ,
gd - bopta increased the number of lesions detected.conclusionliver mr imaging after gd - bopta increases the detection of liver lesions in patients with primary malignant hepatic neoplasm . |
a 50-year - old lady was referred for retinal evaluation to rule out aids - related retinal or ocular disorders .
optic nerves appeared normal . a visual field examination using 30 - 2 program on oculus
center field perimeter was performed to rule out lesions along the visual pathway , as clinical examination could not explain the visual loss or the symptoms .
it showed good reliability in both eyes and a left homonymous hemianopia [ figs . 1 and 2 ] .
magnetic resonance imaging ( mri ) of brain was done to determine the cause of homonymous hemianopia , such as infarct / bleed or space - occupying lesion .
mri scan showed irregular white matter hyperintensity in the right occipital lobe and a hyperintense lesion in the left frontoparietal region in the subcortical and periventricular white matter [ fig . 3 ] .
it also showed irregular white matter hyperintensity and a large area of increased t2-weighted and decreased t1-weighted signal in the left frontal lobe posteriorly involving the subcortical white matter and extending into the centrum semiovale and corona radiata , without enhancement or mass effect .
mri showing lesions in right parieto - occipital lobe and elsewhere she was referred to a neurologist for evaluation .
a cerebrospinal fluid ( csf ) tap was advised for polymerase chain reaction ( pcr ) evaluation for jc virus .
pml is a progressive fatal demyelinating disorder associated with oligodendroglial infection by the human papovavirus jc .
occasional cases are described in pregnancy , and some cases may have no identifiable evidence of immunosuppression .
the causative agent , the jc virus , invades oligodendroglial cells , causing multiple foci of demyelination .
after the primary infection , jc virus remains latent in kidneys and lymphoid organs . up to 64% of healthy adults have shedding of jc virus in urine in the absence of any clinical symptoms , suggesting that asymptomatic active jc virus infection is common in immunocompetent persons .
the presenting symptoms in a case of pml are focal deficits like mental deterioration , speech disturbance , ataxia , paralysis , hemiparesis , facial weakness , memory failure , and also ophthalmic symptoms like nystagmus , homonymous hemianopia and diplopia with cranial nerve palsy in one eye and cortical blindness in the other eye .
previously reported cases are different from the one we are presenting here , as our patient had come with nonspecific visual complaints and no other neurological symptoms .
however , pml should also be suspected in the differential diagnosis of apparently healthy patients with focal deficits , like our patient who had no other symptoms except some visual disturbances in both eyes which she could not categorize .
the purpose of presenting this case was to highlight the fact that we , as ophthalmologists , may be the first to see patients with pml and we should have a high degree of suspicion in an appropriate clinical setting .
this would help us to carry out necessary tests such as visual field examination and , if necessary , an mri scan to arrive at a diagnosis of pml which is a potentially life - threatening disease but may be helped by highly active anti - retroviral therapy ( haart ) .
pml should be kept in mind along with other ocular manifestations , such as cmv retinitis , which are commoner .
diagnosis of pml may be difficult . because a large percentage of the population is seropositive for jc virus ,
csf identification of jc virus by pcr is useful and studies suggest a sensitivity of 95% and specificity of 9099% .
the mri findings are characteristic in pml , with a high t2 signal and a low t1 signal which does not enhance with gadolinium and has no mass effect .
pml is uniformly fatal , and the survival rate is only a few months following the diagnosis .
there are recent reports of improved survival following aggressive haart in hiv , and specific jc antiviral treatment with interferon or cidofovir favor early diagnosis .
hence , we should consider pml in all patients who present with progressive neurological deficits ( such as visual field defects ) which are usually , but not always multifocal . if jc virus is absent in the csf , brain biopsy should be considered . | we present a case of a human immunodeficiency virus ( hiv ) positive patient who was referred for retinal evaluation to rule out ophthalmic manifestations of acquired immunodeficiency syndrome ( aids ) .
she complained of some disturbance in vision in both eyes .
fundus examination showed no abnormality .
perimetry , done to rule out optic nerve pathology , showed a left homonymous hemianopia . magnetic resonance imaging ( mri )
scan showed features of progressive multifocal leukoencephalopathy ( pml ) .
she had no other neurological symptoms or signs . |
helicobacter pylori is an important human pathogen and more than two third of the world population are infected mostly in developing countries .
helicobacter pylori is a gram - negative , spiral shaped and microaerophilic bacteria with persistence colonization in gastric mucosa , causes gastroduodenal inflammation and destruction , resulting in diseases such as duodenal ulcer disease , gastric ulcer disease , iron and/or vitamin b12 deficiency , gastric adenocarcinoma , and primary b - cell gastric lymphoma ( 15 ) .
when h.pylori discovered by warren and marshall , effective therapy developed for this infection and resulted in remarkable change in management of pud and dyspepsia and also gastric mucosa - associated lymphoma .
h.pylori therapy has been used for decades , but for the last decade the efficacy of treatment are declining and much of the decline in effectiveness is attributable to increasing antibiotic resistance due to h.pylori strains .
resistance to antimicrobial drugs is a major cause of treatment failure and is largely responsible for the decline in eradication rates .
different regimens have been used so far in patients with h.pylori infection , including first line therapy , second line therapy , sequential therapy and concomitant therapy .
there has been a decline in the effectiveness of recommended therapies resulting in unacceptably low cure rates ( i.e. 80% ) ( 68 ) . among different regimens for h.pylori eradication
, clarithromycin - containing triple therapy resistance is very important to treatment outcome because it dramatically reduces eradication rates .
in fact , eradication rates with this regimen in patients harboring a clarithromycin - resistant strain of h.pylori are likely to be less than 30% . therapy for h.pylori infection lost its way in part because of cure rates decline ( largely because of an increasing prevalence of resistant organisms ) .
physicians are unaware that the cure rate with triple therapy has fallen down to below 80% in most places .
one reason for failure of eradication is the lack of routine post therapy evaluation and testing universally which provide an early warning of increasing antibiotic resistance .
therefore physician should know about h.pylori resistance strains , looking for alternative and effective therapy .
issues to be considered when selecting a regimen for treatment of an infectious disease include effectiveness , simplicity , tolerability , adverse effects , the prevalence of antibiotic resistance in the community , dose , duration , costs , and whether and how much control of gastric ph is needed ( 9 , 10 ) .
one way to overcome this problem is to act as the same way for other transmissible infection , to cure patients and evaluate resistance . unfortunately practicing physicians have no knowledge about the rate of resistance in their population , failing to order follow - up testing to prove h.pylori eradication after a course of antimicrobial therapy .
the importance of follow - up testing to confirm eradication of h.pylori infection in patients with ulcer disease has been highlighted in recent studies that have shown that patients who did not undergo such testing were at a greater risk of ulcer recurrence and recurrent upper gastrointestinal bleeding .
all physicians are now aware of the importance of testing for and treating h.pylori infection in patients with a documented peptic ulcer .
therefore , all patients with an ulcer should undergo follow - up testing to prove cure .
non - endoscopic tests that can be used to reliably document eradication include the urea breath test ( ubt ) and the fecal antigen test ( fat ) .
two versions of the ubt are commercially available , one using a small dose of radioactive 14c and another that uses the non - radioactive isotope 13c .
studies have found the monoclonal version of the fat to be accurate in the post - treatment setting ( 11 , 12 ) .
polyclonal versions of the fat appear to be less reliable and should be avoided in the post - treatment setting .
the accuracy of both ubt and fat can be affected adversely by the recent use of ppis , bismuth , or antibiotics . despite being the cheapest and most widely available diagnostic modality , h.pylori antibody ,
biopsy - based testing including the rapid urease test or histology also can be used to document h.pylori eradication . because h.pylori infection often becomes patchy after antibiotic therapy , a minimum of 4 biopsy specimens
should be obtained from the proximal and distal stomach when establishing h.pylori eradication with histology .
although the rapid urease test remains highly specific , its sensitivity is reduced after antibiotic or ppi therapy .
unfortunately , h.pylori culture is less sensitive than histology or the rapid urease test and is available in only a small number of centers . given these practical limitations , culture should be considered only in cases in which h.pylori infection has persisted despite multiple courses of antibiotic treatment .
polymerase chain reaction is a dna amplification technique that can be performed on mucosal tissue specimens .
this powerful diagnostic tool is not yet available for clinical practice ( 11 , 12 ) .
the roles that the organism , gastric environment , hosts and drug regimens play in treatment failures are often inter - related .
drug regimens should be designed to overcome drug - resistant and dormant forms of the organism , a high bacterial load , the typically low gastric ph , impaired mucosal immunity and the busy lifestyle of the human host ( 13 ) .
h.pylori typically resides within the human stomach , and populations of organisms occupy different environments , each with its own challenges .
the majority of organisms are found within the mucus layer , which is technically outside of the body .
many are found attached to surface cells and a few are found even within epithelial cells ( 1416 ) .
most importantly , at any time , a proportion of the organisms is either not replicating or is replicating very slowly , which represents a challenge for antibiotics that require microbial replication to kill the organisms ( e.g. , clarithromycin and amoxicillin ) ( 1719 ) . the best method to determine which drug the infection is resistant to , is to test for antimicrobial susceptibility .
as noted above , this can be done using stool specimens for clarithromycin and fluoroquinolone susceptibility which can be assessed using molecular techniques , but this is not available for the other commonly used drugs . as a general rule , when antimicrobial susceptibility testing is not feasible , one can presume that the infection is resistant to antibiotics that the patient has taken previously in which resistance is common or develops rapidly ( eg , metronidazole , clarithromycin or fluoroquinolones ) ( 20 ) .
h.pylori treatment failures may also occur independently of resistance that is , treatment may fail but the organism remains susceptible to the antibiotic .
this is most commonly seen with amoxicillin where failure is rarely caused by acquired resistance .
this form of reversible resistance is termed phenotypical antibiotic resistance and it often due to the presence of a persistor or nonreplicating population of organisms ( 2123 ) .
bacterial populations oscillate between a non - replicating and replicating state or from intracellular to extra - cellular environments .
thus they oscillate between a phenotypically resistant and a phenotypically susceptible state during which they can be eradicated .
one solution is to extend the duration of treatment such that the antibiotic will be present during at least one period of susceptibility ( 24 ) .
an alternative approach is to force the organism to enter the replicative state and become susceptible to the antibiotic ( 2527 ) .
the increasingly low treatment success rates should have been a calling for action resulting in widespread discussion of the problem , and rigorous studies in a variety of populations using different antimicrobial agents , doses , formulations and durations , to identify new effective treatments on the results - based approach designed to be efficient and to minimize patient risk and drug exposure ( 28 ) .
the fact that the most commonly recommended treatments no longer cured even 80% of infections in many populations was not appreciated by general clinicians ( 14 ) . in general , and in most countries ,
metronidazole resistance should be considered as ubiquitous and increased doses must be used routinely unless it has been proven that high cure rates are maintained with the standard doses and/or treatment durations shorter than 14 days .
declining treatment success has reached the point where triple regimens containing clarithromycin should be abandoned as an empiric first - line treatment . when confronted with a patient who has failed treatment , which the issues include : ( 1 ) what antibiotics are the infection likely to be resistant to ? ( 2 ) which drugs can the patient not take either because of an allergy or side effects ? and ( 3 ) which drugs are available locally ?
besides of considerations regarding allergies and the local availability of the drugs , we recommend that clinicians use the following general rules when treating patients with a h.pylori infection : ( 1 ) do not use legacy triple therapy consisting of a ppi , clarithromycin and amoxicillin unless it has been proven to be highly effective locally ( eg , eradication > 90% in per - protocol analyses ) ; ( 2 ) use higher doses of drugs ( eg , 500 mg of clarithromycin , metronidazole and tetracycline ) unless it has been shown that lower doses are equally effective ; ( 3 ) use 14 day duration unless a shorter duration has been shown locally to be equally effective ( eg , for clarithromycin and fluoroquinolones ) ; ( 4 ) do not use a triple regimen containing clarithromycin , if clarithromycin is commonly prescribed locally or the patient has taken clarithromycin in the past , for any indication ; ( 5 ) avoid fluoroquinolones if a quinolone ( eg , ciprofloxacin , levofloxacin or moxifloxacin ) has been given previously , even for any indication ; and ( 6 ) following treatment failure , do not reuse drugs for which resistance is likely to have developed ( ie , clarithromycin and fluoroquinolones ) . a bismuth triple regimen consisting of a bismuth salt ,
metronidazole / tinidazole and tetracycline was the first successful h.pylori treatment ; initially it provided treatment success > 95% even without the use of an antisecretory drug .
resistance to bismuth does not occur , and it is probably the most underutilised agent .
treatment success for triple drug regimens containing amoxicillin does not always appear to be significantly lowered in the presence of amoxicillin resistance , suggesting that resistance may often be overestimated ( 11 ) , especially in areas where a relatively high prevalence ( ie , > 20% ) is reported and where appropriate tests for resistance are not utilised .
resistance to clarithromycin , on the other hand , has increased over time ( 18 , 19 ) .
the fact that treatment success reliably increases as the duration of treatment increases from 3 to 14 days with amoxicillin and a ppi is probably an example of phenotypic resistance .
subsequent experience showed that eradication was reduced in the presence of metronidazole - resistant h.pylori and that this could be largely overcome by increasing the dose of metronidazole and duration and/or adding a ppi .
as such , the dose of metronidazole ( e.g. , 1500 mg per day ) and duration ( 14 days ) are considered optimum especially in areas where metronidazole resistance is more than trivial ( 2931 ) . in many populations , quadruple regimens containing a bismuth compound , metronidazole ( 500 mg three times a day ) , tetracycline ( 500 mg four times a day ) and a ppi ( standard dosing twice daily ) can achieve effectiveness ( 18 ) .
given the potential benefits of sequential therapy in patients with clarithromycin - resistant h.pylori infection , one wonders about its use in patients with persistent infection . at present , there are no data available on the use of sequential therapy as a salvage regimen .
several other antibiotics have been used in salvage regimens including levofloxacin , rifabutin , and furazolidone . a suitable alternative to quadruple therapy is levofloxacin based triple therapy consisting of levofloxacin 500 mg once daily , amoxicillin 1 g twice daily , and a ppi twice daily for 10 days .
furazolidone is a synthetic derivative of the nitrofuran class of antimicrobials , which also has been evaluated in a number of studies with eradication rates ranging from 52% to 90% in the treatment of persistent h.pylori .
it is difficult to assess the efficacy of furazolidone - based salvage therapy owing to the variability in treatment regimens . in these studies , the daily dose of furazolidone varied from 200 to 600 mg .
furthermore , a variety of triple- and quadruple - drug regimens were used with treatment durations ranging from 7 to 14 days .
side effects can be substantial in these furazolidone - based therapies , occurring in as many as 35% of patients , with vomiting , nausea , and dizziness being reported most commonly .
furazolidone also may interact with a variety of foods and other drugs given its effect on monoamine oxidase as well as glucose-6-phosphate dehydrogenase activity and its potential disulfiram like reaction with alcohol .
furazolidone has fallen out of favor related to its adverse event profile and limited availability ( 3133 ) .
there is less consensus regarding treatment regimens for persistent h.pylori infection despite 2 or more previous courses of antibiotics .
bismuth - based quadruple therapy , levofloxacin - based triple therapy , rifabutin - based triple therapy , and furazolidone - based regimens have been investigated .
a 14-day course of bismuth quadruple therapy yielded an eradication rate of 95% ( 95% ci , 85%99% ) in 42 patients whereas another study in which 18 patients received a 7-day course of therapy reported an eradication rate of only 33% .
levofloxacin triple therapy was found to eradicate h.pylori in 86% , whereas a more recent study showed an eradication rate of only 60% ( 95% ci , 50%70% ) in 100 patients who had failed 2 previous courses of therapy .
concomitant therapy with non - bismuth containing , four - drug , three - antibiotic therapy , was introduced before sequential therapy and there is experience of its use in about 1,000 patients ( 3442 ) .
it consists of four drugs- a ppi , clarithromycin , metronidazole or tinidazole , and amoxicillin - all given twice daily .
the duration of concomitant therapy has ranged from 3 days to 7 days and it has produced grade b results , similar to those obtained with sequential therapy ( 3442 ) .
studies are needed to test whether extending the duration of therapy will improve these results . as with sequential therapy , concomitant therapy
would probably be a poor choice in the presence of h.pylori that are resistant to clarithromycin and metronidazole , or for treatment after multiple drug regimes have failed , as those patients can be expected to have multidrug resistant infections .
importantly , however , traditional triple therapy can easily be converted to concomitant therapy by the addition of 500 mg of metronidazole or tinidazole twice daily ( 4356 ) .
thus , we recommend including at least one antibiotic the patient has not previously taken .
sequential and concomitant treatments expose the patient to both clarithromycin and metronidazole / tinidazole , and therefore we do not recommend that both drugs be used in the rescue treatment as well .
however , the worldwide rapid increase in fluoroquinolone resistance has undermined this approach in many areas and one must fall back on the only use what works locally rule ( 33 , 57 , 58 ) .
in addition , one should generally expect the same treatment success rate for first , second and even third treatment regimens if the organisms are susceptible .
thus , if one initially used a clarithromycin containing concomitant or sequential regimen , one of the reasonable second choices would be 14 day bismuth quadruple regimen .
if this bismuth quadruple rescue treatment is ineffective in the local population , or when metronidazole is not a viable drug option , metronidazole can be replaced by furazolidone ( 100 mg ) .
as previously mentioned , ppi plus amoxicillin dual treatment can be improved by increasing the frequency and dose of the ppi and extending treatment duration . with higher doses and longer durations ,
we recommend adding a third drug ( not previously used by the patient ) to a 14 day ppi plus amoxicillin regimen .
a fluoroquinolone ( once a day ) is a good choice for the third drug , provided that resistance is not present .
the other option that is commonly used is rifabutin ( 150 mg twice a day ) ( 5256 ) .
the increasing prevalence of drug resistance has complicated successful therapy . therefore we must consider and look for appropriate therapy .
ideally , therapy should be based on pretreatment drug susceptibility testing , and empiric use of eradication therapies should assume the presence of antimicrobial drug resistance and use increased doses for 14 days .
clarithromycin - containing triple therapies now typically produce 80% itt cure rates and are thus no longer acceptable as empiric therapy .
current options for initial treatment include sequential therapy , concomitant therapy , and bismuth - containing quadruple therapy .
advances have shown that phenotypic and genetic resistance to therapy can be successfully dealt with , and what still needs to be done is now clearly identifiable .
an improved appreciation of the role of gastric ph in phenotypic resistance has resulted in high cure rates with high - dose ppi plus amoxicillin dual therapy , although studies are still needed to devise improved dual - therapy based multidrug regimes .
selection of appropriate antimicrobial drugs following treatment failure is best approached by drug - susceptibility testing .
if such testing is not available , we recommended a bismuth - containing quadruple therapy , with substitution of a new drug for the metronidazole or tinidazole and/or the clarithromycin if these agents have been used previously .
one alternative approach would be to use 14 days of treatment with a high - dose ppi and amoxicillin - containing triple therapy with rifabutin , a fluoroquinolone , or furazolidone .
the time is long overdue for us , the h.pylori investigators , to speak up and communicate to clinicians that the treatments they are using are often no longer effective , recommend superior alternative treatments and seek out new highly efficacious treatments . | helicobacter pylori is an important human pathogen and a gram - negative , spiral shaped and microaerophilic bacteria with persistence colonization in gastric mucosa , causes gastroduodenal inflammation and destruction , resulting in diseases such as duodenal ulcer disease , gastric ulcer disease . when h.pylori discovered by warren and marshall , effective therapy developed for this infection and resulted in remarkable change in management of pud and dyspepsia .
nowadays , the increasing prevalence of drug resistance has complicated successful therapy , considering more attention for appropriate therapy . ideally , therapy should be based on pretreatment drug susceptibility testing , and empiric use of eradication therapies should assume the presence of antimicrobial drug resistance and use increased doses for 14 days . |
skin and soft tissue infections caused by non - tuberculous mycobacteria ( ntm ) , which used to be considered unusual , have become more frequent in recent times .
atypical mycobacteria are environmental saprophytes , which may occasionally enter human skin through injuries and cause localized infection
. papules , nodules , plaques , ulcers and panniculitis - like lesions are common manifestations . disseminated infection occurs in immunocompromised patients .
this kind of cutaneous infection is not frequently seen in humans and its diagnosis can be missed unless there is a strong clinical suspicion coupled with microbiological confirmation .
a 52-year old healthy upper middle class , italian male and his 21-year old daughter presented in may 2008 with a history of swelling on of the father 's face and neck , and on the daughter 's buttocks and legs .
the swellings had started approximately three months previously , had gradually increased in size , associated with moderate pain .
both subjects reported that they were swimmers and that they used to travel to egypt in the summer . on physical examination ,
the daughter had purple indurated subcutaneous nodules and plaques were observed on her right buttock .
the father had subcutaneous granulomas on the lateral left side of his neck that had also ulcerated ( figure 1 ) .
both patients reported intermittent discharge from the lesions and associated local non - tender lymphadenitis .
diagnostic aspiration from the swelling had been performed approximately 20 days previously after which the swelling had subsided .
the cytological findings of the aspirate were inconclusive and the swelling recurred within the following few days which led to the patients returning for a repeat evaluation .
laboratory evaluation , including wbc count , chain protein reaction ( cpr ) and antistrept olysin o titre ( as(l)o titre ( asot ) , showed no increase in values .
liver , renal function tests and a chest x - ray were within normal limits .
needle aspiration from the swelling was repeated and subjected to cytological and microbiological evaluations which showed cream colonies that turned yellow when exposed to light . a repeated skin biopsy specimen of the abscess wall showed an acute - on - chronic infection with edematous granulation tissue and some foreign - body giant cells .
molecular diagnosis can identify species of mycobacteria polymerase chain reaction - restriction fragment of the hsp65 gene .
after two months of treatment , the lesions healed completely . at 1-year follow up , there was no recurrence of the disease .
( b ) a painful abscess with associated erythema and edema of the right buttock .
( a )
( b ) a painful abscess with associated erythema and edema of the right buttock .
two well - known species , m. tuberculosis and m. leprae , have been known for centuries to cause immense human suffering .
the pathogenic potential of most other mycobacteria , present in the environment as saprophytes , has been recognized since the beginning of the 20 century .
it is a waterborne mycobacterium that commonly infects fish and amphibians all over the world .
categories at risk are home - aquarium enthusiasts , swimmers , aquarium staff , marine - life handlers , anglers , and oyster workers . in most cases
, they present as a granulomatous infection localized in the skin , typically following minor trauma and other surgical procedures .
the usual presentation is trauma to the skin in non - chlorinated water or salt water , and after about two weeks of inoculation it will develop into a localized papulonodular lesion which eventually ulcerates . the clinical syndrome is variable , the pathology is non - specific and culture is needed for definite diagnosis . infections sometimes heal spontaneously , but drug treatment is usually necessary for several months in order to cure the infection .
knowledge of the relative frequency of post - travel related skin disorders , including their geographical and demographic risk factors , will allow for effective pre - travel counseling , as well as improve post - travel diagnosis and therapeutic intervention . in our patients ,
suspicion was aroused because they were swimmers who used to travel to egypt during the summer and had reported contact with aquatic animals , although they could not recall how many months after the trip the lesions appeared .
clinicians seeing patients post - travel should be alert to travel - related skin diseases . to prevent and manage skin - related morbidity during travel , international travelers should avoid direct contact with sand , soil , and aquatic animals . sometimes lesions are aspecific and appear many months later so it is important to keep record of any traveling and seek immediate medical care . with the increased numbers of immunocompromised patients , it is likely that we will see a rising trend in these infections .
a high index of suspicion is the key to diagnosis and appropriate samples should be sent for mycobacterial culture before the use of antibiotics . | environmental mycobacteria are the causative factors of an increasing number of infections worldwide .
cutaneous infections as a result of such mycobacteria are often misdiagnosed , and their treatment is difficult since they can show in vivo and in vitro multidrug resistance .
absence of pathognomonic clinical signs and variable histological findings often delay diagnosis .
we report a case of localized recurrent soft tissue swelling by mycobacterium marinum in 2 members of the same family .
the cases are being reported for their uncommon clinical presentation and the associated etiological agent .
patients recovered completely following therapy with rifampicin 600 mg plus isoniazide 300 mg daily for 45 days . |
in conventional dental brazing - defined as soldering over a temperature of 450c - the parent metals are joined with different types of metals , which may reduce corrosion resistance because of galvanic corrosion between metals57 .
the results of solmi , et al.14 ( 2004 ) highlighted the superior biological quality of laser - welding over brazing .
other authors characterized orthodontic materials as non cytotoxic except for silver soldered joints10 . while testing the cell reactions of osteoblasts , fibroblasts and keratinocytes , sestini .
et al.13 ( 2006 ) found a good tolerance of electrical resistance and laser welding , while traditional silver solder was toxic for osteoblast differentiation , fibroblast viability and keratinocyte growth .
the strength of silver soldered joints used to fabricate space maintainers and orthodontic appliances is critical to their success10,12,13,2830 .
another method employed for joining metal frameworks is laser welding14,8,1720 . in order to weld dental alloys , crystals of yttrium aluminum garnet ( yag ) doped with neodymium ( nd )
the factors affecting the mechanical strength of laser welded joints are the wave length , peak pulse power , pulse energy , output energy , pulse duration , pulse frequency , and spot diameter of the laser - welding machine , and the type of metal used9,11,15,21 .
many laser welding machines used in dentistry have variable settings for output energy ( voltage or current ) , spot diameter and pulse duration .
different combinations of these conditions can change the penetration depth of the laser into the metals and affect the joint strength of the laser welded restoration9,11,15,21,24 . in 2005
two different devices for orthodontic purposes were developed based on tungsten inert gas ( tig ) welding , a well known arc welding process .
the welding heat is produced with the aid a light bow between tungsten anode and metal .
laser and tig welding can weld parent metals without solder or with material consisting of the same parent metal16 .
therefore , the corrosion resistance may be increased because the same metal is used . due to their advantages ,
currently , only little information concerning the mechanical strength of these joints is available in dental literature .
therefore , the aim of this study was to compare the mechanical strength of joints made by conventional brazing , tig and laser welding with and without filling material .
five standardized joint configurations of the orthodontic wire material forestanit ( lot : 272 ; forastadent , pforzheim , germany ) in spring hard quality ( 0.9 mm diameter for all joints , 0.5 mm diameter for filling material ) was used ( figures 1 to 5 ) .
the joints were made by 5 different methods : brazing with universal silver solder , tig welding with and without filling material ( welder , schtz dental , germany ) and laser welding with and without filling material ( lwi , schtz dental ) .
laser parameters and welding conditions followed the manufacturer 's recommendations ( table 1 ) . for each joining method , 10 specimens were carefully produced .
the tensile strength of the original wire material with the diameters of 0.9 mm ( n=10 ) were also measured .
measurements of joint length took place at x34 magnification with the aid of a computer - assisted video inspection system vmzm/40 ( jena engineering company , germany ) .
fracture strength measurement of different welding and brazing methods was carried out using a universal testing machine ( zwick 005 .
the wire length between the cross - heads of the machine was standardized as 5 mm .
the full scale load was set at 2000 n with a crosshead speed of 10 mm / min .
the recorded data were analyzed using spss 12.0 statistical software package ( spss inc . ,
statistical analysis was undertaken by one - way analysis of variance ( anova , p=0.05 ) and bonferroni post hoc test ( p=0.05 ) .
means , minima , maxima and standard deviations of the joint length are given in table 2 .
no significant differences between the various joint configurations except for the connections of band to orthodontic wire were found ( anova , p<0.05 ) ( table 3 ) . in this configuration , the mean joint length made by brazing was between 0.5 and 1.0 mm longer than in laser 1 or laser 2 .
means , minima , maxima and standard deviations of the fracture strength of the different joining method are given in table 4 .
mean tensile strengths of the original orthodontic wire ( n=10 , diameter 0.9 mm : 1492 55
compared to these findings welding and brazing significantly decreased the fracture strength ( anova , p<0.001 ) ( table 4 ) . according to manufacturer 's guidance , tig - welding of orthodontic wire to orthodontic band could not been carried out . for brazing ,
the highest fracture strength means were observed in the band - to - wire configuration ( 406.7 116.1 n ) . the lowest means for brazing
were found in the cross joints ( 185.9 36.0 n ) . for tig - welding ,
the highest fracture strength means were observed in the 3-mm - long joints with filling material ( tig 2 : 866.1 136.9 n ) .
the lowest fracture strength means were shown in the 9-mm - long joints ( tig 1 : 548.9 105.3 n ) . except for the cross joints ,
higher fracture strength means were found for tig welding with filling material . in the present study ,
the absolute highest fracture strength means were found in laser welding to joining orthodontic wire of 3 mm length with additional use of filling material ( laser 2 : 997.9 281.7 n ) .
the lowest fracture strength means in laser welding were found in the configuration orthodontic wire to band without filling material ( laser 1 : 328.8 31.7 n ) the anova results are shown in table 5 . in general , statistically significant differences ( p<0.05 ) were found among the various joining configurations and soldered or welded specimens .
statistical comparison of single groups demonstrated a significant decrease of fracture strength means in brazing related to tig- or laser welding except for the band to wire joints ( bonferroni post hoc test , p<0.001 ) ( table 6 ) .
ns= non significant ; level of significance : using additional filling materials higher fracture strength means were achieved with both tig- or laser welding .
statistically significant differences ( bonferroni post hoc test , p<0.05 ) were found between the 9-mm - long joints produced by tig- or laser welding with and without filling materials ( table 6 ) . except for the joints of 9 mm and the band - to - wire configuration , no significant differences ( bonferroni post hoc test , p>0.05 )
concerning the band - to - wire joints , the mean values of fracture strength did not differ significantly between laser 1 and brazing , but a slight tendency to lower means in laser welding without filling material was found ( bonferroni post hoc test , p>0.05 ( table 6 ) .
significantly higher fracture strength means of the band - to - wire joints were shown in laser welding with filling material .
studies about mechanical behavior of welded or soldered orthodontic wires are rare . up to date
, a direct comparison of different brazing and welding methods is missing and the influence of different tig- or laser welding devices can not be estimated .
no scientific studies were found to evaluate the effects of filling material on the fracture strength of tig- or laser welded orthodontic wires .
the results of fracture strength measurements of welded precious and non - precious cast alloys used in fixed or removable prosthodontics can be transferred to orthodontic purposes only with strong limitations8,10 .
the factors affecting the mechanical strength of welded joints have been described in different studies : wavelength , peak pulse power , pulse energy , output energy , pulse duration , pulse frequency and spot diameter of the laser - welding machine , and the type of metal used5,6,2226 .
various authors have demonstrated changes in the welding area and the so - called heat - affected zone in ni - cr - mo , co - cr - mo or titanium alloys depending on welding conditions3,18 .
these authors pointed out that this is probably due to the different refining in the grain size and the substructure that appears during the rapid solidification stage .
wiskott , et al.27 ( 2001 ) found a correlation between definite increase in grain size and increased heat application in brazing , electric resistance and laser welding of au - pd alloy .
however , the authors could not correlate the element analysis with the fracture strength of the specimens .
bertrand , et al.3 ( 2004 ) have observed that a small change in the chemical composition of the ni - based alloys caused a very important difference in the weldability .
accordingly , the results of other authors investigating laser - welded titanium indicated that , under the appropriate conditions , the joint strength of laser - welded titanium was not significantly different from the non - welded parent metal4,9 .
in contrast to these findings , watanbe and topham25 ( 2004 ) did not achieve the same fracture load of non - welded ti- , gold- or co - cr alloys in different configurations of laser welding .
specially for gold- and co - cr alloys only 50% or less of the original measurements were obtained .
babe , et al.2 ( 2004 ) found that the fracture strength for all laser - welded cocr - alloy specimens tended to be lower than those for the controls .
depending on welding conditions the mean fracture force ranged from 224 to 622 n for single - welded specimens and from 252 to 1292 n for the 1.0-mm double welded specimens . only at currents of 270 and 300
a significant differences could not be found from the results for the non - welded control specimens ( 1733 n ) 2 .
rocha , et al.11 ( 2006 ) compared laser and tig welding of non precious alloys .
tig welding increased the flexural strength of ti , co - cr , ni - cr whereas the welded cylinders presented higher flexural strength than non - welded cylinders .
the highest means were observed for co - cr weld by tig and non - welded co - cr .
in contrast , laser welding achieved only 17.5% of the flexural strength of co - cr alloy .
the controversial results of decreasing or increasing mechanical strength of welded precious and non - precious cast alloys were not found for orthodontic materials .
krishnan , et al.8 ( 2004 ) evaluated three orthodontic arch wire alloy materials - stainless steel , beta titanium and timolium as to their laser weld characteristics .
fracture strength differed significantly between the three materials ( stainless steel 363 22 mpa , beta titanium 463 27 mpa , timolium 344 25 mpa ) .
although a comparison to original wires was missing in this study , it could be assumed that laser - welded specimens showed significant lower fracture strength than pure metals ( approximately 1500 - 1800 mpa ) .
a recent study using additional filling material demonstrated higher flexural strength for ti- ( + 18% ) , nicr- ( + 66% ) and cocr- ( + 69% ) laser welded alloys11 . in the present study ,
the increase in fracture strength ranged from 16% and 35% in tig- and laser welding . an additional benefit was observed . in the present investigation ,
a direct comparison between brazing , tig- and laser welding was performed for the first time .
defects of our tests were equal to the clinical findings of complete ruptures without a real conjunction between two metal frameworks .
tig and laser welding showed significantly higher fracture strength means , but the tensile strength of original wire was not achievable .
therefore , welding changed the material attributes and the fact of missing spring hard quality has to be considered in planning of orthodontic appliances . testing the fracture strength , the brand new tig welding appeared to be comparable to the laser welding method and is an interesting low cost and solder free alternative for orthodontic purposes .
however , it should be highlighted that the impossibility to create band - to - wire joints limits the clinical use of tig - welding in orthodontics .
further research is needed to determine the optimal welding parameters for each device and different joining methods , especially to joining orthodontic wires with orthodontic bands .
the use of additional filling material in tig- and laser welding improved the mechanical behavior of orthodontic wire joint configuration and can be recommended for achieving higher fracture strength . | the aim of this study was to compare the mechanical strength of different joints made by conventional brazing , tig and laser welding with and without filling material .
five standardized joining configurations of orthodontic wire in spring hard quality were used : round , cross , 3 mm length , 9 mm length and 7 mm to orthodontic band .
the joints were made by five different methods : brazing , tungsten inert gas ( tig ) and laser welding with and without filling material .
for the original orthodontic wire and for each kind of joint configuration or connecting method 10 specimens were carefully produced , totalizing 240 .
the fracture strengths were measured with a universal testing machine ( zwick 005 ) .
data were analyzed by anova ( p=0.05 ) and bonferroni post hoc test ( p=0.05 ) . in all cases ,
brazing joints were ruptured on a low level of fracture strength ( 186 - 407 n ) .
significant differences between brazing and tig or laser welding ( p<0.05 , bonferroni post hoc test ) were found in each joint configuration .
the highest fracture strength means were observed for laser welding with filling material and 3 mm joint length ( 998 n ) . using filling materials
, there was a clear tendency to higher mean values of fracture strength in tig and laser welding .
however , statistically significant differences were found only in the 9-mm long joints ( p<0.05 , bonferroni post hoc test ) . in conclusion ,
the fracture strength of welded joints was positively influenced by the additional use of filling material .
tig welding was comparable to laser welding except for the impossibility of joining orthodontic wire with orthodontic band . |
acute otitis media ( aom ) is the commonest paediatric bacterial infection , affecting up to 75% of children at some time before age 5 years .
streptococcus pneumoniae and haemophilus influenzae , in particular the non - typable strains ( nthi ) , are responsible for up to 80% of bacterial aom [ 24 ] .
aom is among the primary reasons for antibiotic prescriptions in paediatric outpatients [ 58 ] ; however , many countries recommend a wait and watch approach as it has been found that symptomatic treatment without antibiotics can be safely used in most aom cases [ 911 ] .
data from clinical practice in the uk have shown that 15% of children with aom present with ear discharge , while severe infections , such as mastoiditis , are infrequent ( estimated incidence after aom of 18/10 000 episodes after antibiotics and 32/10 000 episodes without antibiotics ) .
existing data on aom incidence vary considerably due to different case definitions , study designs , age groups , time periods of study , geographical locations , and other factors [ 1519 ] .
previous studies have used either retrospective data from medical chart reviews [ 15 , 19 ] , parental reports , or prospective follow - up of subjects [ 20 , 21 ] .
these approaches can be criticized for different reasons : retrospective reviews might underestimate the true incidence since suspected milder cases might be missed , parental reports are subjective and non - specific to aom that lacks clinical confirmation , and prospective follow - up is sensitive to selection of subjects and diagnostic criteria used , which may result in data which are difficult to compare and generalize across studies . to our knowledge , no study has addressed all these different approaches , leaving the potential bias of incidence figures by study design uncertain , while in this cohort study of aom the same study design was applied to each country .
data were obtained with a standardized methodology from retrospective review of medical charts and prospective follow - up based on physician and parental reports to assess all potential aom including suspected , probable , and confirmed episodes .
the objective of the study was to estimate the incidence , clinical presentation and severity of childhood aom in clinical practice in five european countries with different healthcare systems .
this was a large , multi - country , multi - centre , epidemiological , observational cohort study which utilized retrospective review of medical charts in addition to prospective follow - up data collection through both physician and parental reports to collect information on incidence , complications and symptoms of aom .
data on clinical management , health economics , and quality of life , which were also collected during the study , are presented elsewhere [ 22 , 23 ] .
the study took place in germany , italy , spain , sweden , and the uk .
the target enrolment was 1250 subjects per country , with no signs or symptoms of aom or other upper respiratory tract infections at the time of enrolment , for whom medical records covering the previous year ( or since birth , if aged < 1 year ) were available at the investigational site and who were expected to be available for 12 months of follow - up .
all sites made attempts to balance enrolment between the 02 and 35 years age groups in order to achieve about the same number of children in each group .
children were enrolled from july 2008 to january 2009 at 26 paediatric practices in germany , 21 family paediatric practices in italy , 12 paediatric practices in spain , and at ten general practices in the uk . in all countries except sweden ,
the majority of children were enrolled during a visit to the investigators ' practices ; however , investigators could also recruit patients through mailings or phone calls . in sweden
primary care for children is mostly provided by paediatricians in germany , italy , and spain . in the uk and sweden
depending on the nature of the health condition and its severity , these primary - care physicians may then refer their patients to specialists for secondary or tertiary care .
a total of 5882 children were enrolled at 73 medical practices , resulting in a cohort of 5776 children for the retrospective period of the study , following exclusion of 106 children who did not meet the inclusion criteria .
the 106 exclusions were due to five children outside the study age group , 27 without medical records available , two for whom consent was not provided , one not available for 12 months of follow - up , 28 who had aom at enrolment , and 47 who had signs of an upper respiratory infection .
after exclusion of 12 more children due to lack of follow - up contact information , a total of 5764 children were followed - up prospectively .
data on hib vaccination , which was introduced in europe in the early 1990s , was not collected ; however , available vaccination rates suggest that hib immunization coverage in 1-year - olds was > 93% in all five countries in 2011
. data on the frequency of suspected , probable and confirmed aom , severity and complications of any aom episodes , and aom symptoms were collected through retrospective review of medical charts and prospective follow - up using physician and parental reports . for the retrospective period of the study ,
the chart was examined for aom - related visits in the year prior to enrolment ( encompassed time period from 2007 to 2008 ) for children aged 1 year old at enrolment . for children
aged < 1 year at enrolment , all available medical history in the medical chart for was reviewed by the investigator .
for the prospective period of the study , enrolled children were followed - up prospectively for 1 year ( encompassed time period from 2008 to 2010 ) to collect data on all aom episodes .
data for the prospective study period were collected at visits for aom at the investigator 's practice or through any available case report giving details of the aom symptoms , aom - related medical procedures / therapy and concomitant medication if the visit was to another medical practice or emergency department .
parents were contacted every 2 months and asked about any respiratory / aom - related symptoms lasting more than 48 h ( even if no medical care was sought ) and about visits to the emergency department or other healthcare providers .
every month local investigators in participating practices logged the total number of aom - related visits and total number of visits for any children within the 02 and 35 years age groups . in sweden
data on aom - related and total number of visits were used to compare incidence rates in the study population to the overall incidence in the total population at participating centres .
a suspected episode was defined as any aom - related symptom reported only by the parents including ear pain or discharge or tugging plus one of the following : fever , runny nose , sore throat , cold - like symptoms , conjunctivitis , decreased appetite , vomiting , diarrhoea , trouble sleeping , irritability or apathy .
a probable episode was defined as an aom episode diagnosed by a physician and documented in the medical chart , regardless of any documentation of symptoms .
a confirmed episode was defined as a probable case in addition to a visual appearance of the tympanic membrane , i.e. redness , bulging , loss of light reflex , the presence of acute middle - ear effusion ( as shown by otoscopy or tympanometry ) , and the presence of at least two of the following symptoms : ear pain , ear discharge , hearing loss , lethargy , irritability , anorexia , vomiting , diarrhoea , or fever ( 380c , rectal temperature 385c ) .
alternatively , during the prospective study , a confirmed episode could be a probable episode supported by a positive bacterial culture of the middle ear fluid ( after spontaneous perforation or tympanocentesis ) , if this procedure was routinely undertaken by the treating physician .
a new episode of aom was defined as an aom episode after a 30-day symptom - free interval since the resolution of the previous aom episode .
complicated aom was defined as medically documented aom associated with mastoiditis , labyrinthitis , bell 's palsy , petrositis , meningitis , epidural abscess , sepsis , cerebral vein thrombosis or any other medically documented complication with a timely and causal relationship to aom .
the formula used to calculate the aom episode incidence rate ( number of episodes/1000 subject - years ) was the following :
where n is the total number subjects in the cohort under study or in a subgroup of this cohort ( e.g. age group strictly <3 years ) , i is the number of aom episodes for subject i , and i is the number of days of the surveillance period for subject i. for the prospective study , the surveillance period of one subject was defined as the duration from the enrolment until the last follow - up contact for this subject or until the subject was aged 6 years : end date start date + 1 . for calculation of incidence by age group , i and i
were computed over the period starting from enrolment or entry date in the given age group ( e.g. third birthday for the 35 years age group ) until the last follow - up or leaving date from the given age group ( e.g. third birthday for the 02 years age group , and sixth birthday for the 35 years age group ) . the exact poisson confidence limit method was used to calculate confidence intervals .
the categories of confirmed , probable , and suspected aom episodes were considered as mutually exclusive in the analysis .
all statistical analyses were performed using sas , version 9.1 or later ( sas institute inc . ,
usa ) , and microsoft excel ( 2002 sp3 or later ) , for graphical purposes .
the mean age of the 5764 children at enrolment was 315 months ( s.d .
= 208 ) , and 487% ( n = 2806 ) were female ( table 1 ) . at the beginning of the prospective study ,
582% ( n = 3357 ) of children reported having received at least one dose of the 7-valent pneumococcal conjugate vaccine ( pcv7 ; prevnar/prevenar , pfizer inc . ,
usa ) , ranging from 233% in sweden to 491% in italy , 672% in germany , 745% in the uk , and 840% in spain .
pcv7 vaccination status was unknown for 355 children , mainly based in sweden and italy .
table 1.demographic characteristics at enrolment of children aged 05 years in five european countriescharacteristicgermany ( n=1258)italy ( n=1267)spain ( n=1189)sweden ( n=1243)uk ( n=807)total ( n=5764)age ( months ) , means.d.32020831521031221033519728121431520802 years age group , n ( % ) 652 ( 518)695 ( 548)641 ( 539)701 ( 564)489 ( 606)3178 ( 551)35 years age group , n ( % ) 606 ( 482)572 ( 452)548 ( 461)542 ( 436)318 ( 394)2586 ( 449)gender , n ( % ) female632 ( 502)615 ( 485)554 ( 466)609 ( 490)396 ( 491)2806 ( 487 ) male626 ( 498)652 ( 515)635 ( 534)634 ( 510)411 ( 509)2958 ( 513)data presented here are for the children included in both the retrospective and prospective periods of the study , and do not include the 12 children who participated only in the retrospective study .
demographic characteristics at enrolment of children aged 05 years in five european countries data presented here are for the children included in both the retrospective and prospective periods of the study , and do not include the 12 children who participated only in the retrospective study . based on the retrospective period of the study , 18% ( 1038/5764 ) of children experienced 1376 aom episodes in the previous year .
the proportion of medically diagnosed episodes that were confirmed episodes was lowest in italy ( 121% , 24/198 ) and the uk ( 123% , 19/154 ) , and highest in sweden ( 233% , 73/313 ) and germany ( 239% , 74/309 ) ( table 2a ) . of children who experienced at least one aom episode , 228% ( 237/1038 ) had more than one episode , 67% ( 70/1038 ) had more than two episodes , and 2% ( 21/1038 ) had more than three episodes ( fig .
1 ) . the percentage of children who experienced only one episode varied by country from 694% ( 188/271 ) in spain to 861% ( 142/165 ) in italy . the overall incidence rate of aom based on the retrospective study was 268/1000 person - years [ 95% confidence interval ( ci ) 254283 ] , and was lowest in italy ( 176 , 95% ci 153203 ) and highest in spain ( 387 , 95% ci 350427 ) ( fig .
1.percentage of children aged 05 years in five european countries with 1 , 2 , 3 , or 4 acute otitis media ( aom ) episodes as diagnosed by a physician during ( a ) the 12-month ( 20072008 ) retrospective study period , and ( b ) the 12-month ( 20082010 ) prospective study period in children aged 05 years in five european countries .
2.incidence of acute otitis media episodes in children aged 05 years in five european countries as diagnosed by a physician and documented in the medical chart during the 12-month ( 20072008 ) retrospective study period and 12-month prospective study period ( 20082010 ) in children aged 05 years in five european countries .
table 2a.number of confirmed and probable acute otitis media episodes in children aged 05 years in five european countries as diagnosed by a physician and documented in the medical chart during the 12-month ( 20072008 ) retrospective study periodconfirmedprobabletotal medically diagnosedgermany74 ( 239%)235 ( 761%)309italy24 ( 121%)174 ( 879%)198spain86 ( 214%)316 ( 786%)402sweden73 ( 233%)240 ( 767%)313uk19 ( 123%)135 ( 877%)154total276 ( 201%)1100 ( 799%)1376 percentage of children aged 05 years in five european countries with 1 , 2 , 3 , or 4 acute otitis media ( aom ) episodes as diagnosed by a physician during ( a ) the 12-month ( 20072008 ) retrospective study period , and ( b ) the 12-month ( 20082010 ) prospective study period in children aged 05 years in five european countries
. incidence of acute otitis media episodes in children aged 05 years in five european countries as diagnosed by a physician and documented in the medical chart during the 12-month ( 20072008 ) retrospective study period and 12-month prospective study period ( 20082010 ) in children aged 05 years in five european countries .
number of confirmed and probable acute otitis media episodes in children aged 05 years in five european countries as diagnosed by a physician and documented in the medical chart during the 12-month ( 20072008 ) retrospective study period at least one sign or symptom was documented in the medical chart during at least one visit for 876% ( 1205/1376 ) of episodes . the most common sign or
symptom was redness of the tympanic membrane , reported for 528% ( 727/1376 ) of episodes , and ear pain , reported for 484% ( 666/1376 ) of episodes .
ear discharge was reported for 144% ( 198/1376 ) of episodes and varied by country from 26% in germany to 91% in italy , 152% in spain , 182% in the uk , and 265% in sweden .
complications occurred in < 1% of episodes ( 7/1376 ) : sepsis ( n = 1 ) , hospitalization due to unknown reason ( n = 1 ) , dehydration ( n = 1 ) , otitis media with effusion ( n = 2 ) and unspecified ( n = 2 ) .
five of the seven complications were in the 02 years age group and two were in the 35 years age group .
spontaneous perforation of the tympanic membrane was recorded for 43% ( 59/1376 ) of episodes , ranging from < 2% in germany , italy , and
spontaneous perforation was reported for a similar proportion of episodes in children in both age ranges .
a total of 1419 aom episodes , as diagnosed by physician , were experienced by 1113 children during the prospective study .
overall , 349% ( 495/1419 ) of these medically diagnosed episodes of aom were classified as confirmed , ranging from 183% ( 33/180 ) in the uk to 44% ( 142/323 ) in germany , and 651% ( 924/1419 ) as probable , ranging from 56% ( 181/323 ) in germany to 817% ( 147/180 ) in the uk ( table 2b ) . of children who experienced at least one aom episode , 203% ( 226/1113 )
had more than one , 55% ( 61/1113 ) had more than two , and 1% ( 11/1113 ) had more than three ( fig .
the percentage of children who experienced only one episode varied by country , from 728% ( 198/272 ) in spain to 853% ( 168/197 ) in italy .
table 2b.number of confirmed , probable and suspected acute otitis media episodes in children aged 05 years in five european countries as diagnosed by a physician or reported by the parents during the 12-month ( 20082010 ) prospective study periodconfirmedprobabletotal medically diagnosedsuspected ( parent - reported)germany142 ( 440%)181 ( 560%)323193italy101 ( 421%)139 ( 579%)24059spain106 ( 283%)268 ( 717%)37447sweden113 ( 374%)189 ( 626%)302156uk33 ( 183%)147 ( 817%)180145total495 ( 349%)924 ( 651%)1419600twelve children included in the retrospective period of the study ( table 2a ) did not have follow - up information available and are therefore not included in the prospective study ( table 2b ) .
number of confirmed , probable and suspected acute otitis media episodes in children aged 05 years in five european countries as diagnosed by a physician or reported by the parents during the 12-month ( 20082010 ) prospective study period twelve children included in the retrospective period of the study ( table 2a ) did not have follow - up information available and are therefore not included in the prospective study ( table 2b ) .
the overall incidence rate of aom episodes as diagnosed by a physician during the prospective study was 256/1000 person - years ( 95% ci 243270 ) .
the incidence rate was lowest in italy ( 195 , 95% ci 171222 ) and highest in spain ( 328 , 95% ci 296363 ) ( fig .
the incidence rate was higher in the 02 years age group ( 299 , 95% ci 279320 ) than in the 35 years age group ( 212 , 95% ci 195230 ) ( table 3 ) . in italy incidence rates were very similar between the age groups .
the incidence rate of confirmed aom was 90 ( 95% ci 8298 ) , and the incidence rate of probable aom was 167 ( 95% ci 156178 ) .
table 3.incidence of acute otitis media ( per 1000 person - years ) as diagnosed by a physician during the 12-month prospective study period ( 20082010 ) in children aged 05 years in five european countries02 years old35 years
oldtotal number of eventsincidence ( 95% ci)total number of eventsincidence ( 95% ci)germany182311 ( 267359)134218 ( 183258)italy119193 ( 160232)113197 ( 162237)spain223392 ( 342447)148263 ( 223309)sweden204344 ( 298394)98174 ( 141212)uk108247 ( 203298)66202 ( 156257)total836299 ( 279320)559212 ( 195230)ci , confidence interval .
incidence of acute otitis media ( per 1000 person - years ) as diagnosed by a physician during the 12-month prospective study period ( 20082010 ) in children aged 05 years in five european countries ci , confidence interval .
the number of children under surveillance for prospective visits was relatively stable from november 2008 to august 2009 ( ranging from 5026 to 4381 , respectively ) . over this time period
the monthly number of aom visits was higher during the winter period , with the highest number of aom visits in december 2008 , when there were 240 aom visits among the 5182 children under surveillance ( 46% ) , and the lowest number of visits during august of 2009 , when there were 25 aom visits among the 4381 children under surveillance ( 06% ) .
overall , 989% ( 1403/1418 ) of episodes were associated with at least one sign or symptom in the prospective study ( data missing for one child ) .
the most frequently experienced symptoms were ear pain , reported for 683% ( 968 ) of episodes , followed by redness of the tympanic membrane , reported for 673% ( 955 ) of episodes .
the proportion of children with ear pain was higher in those aged 35 years than in those aged 02 years ( 843% vs. 572% ) .
ear discharge was reported in 169% ( n = 240 ) of episodes , ranging from 121% in italy and 127% in germany to 173% in the uk , 174% in spain and 245% in sweden .
there were no reports of sepsis , mastoiditis , labyrinthitis , bell 's palsy , petrositis , meningitis , epidural abscess or cerebral vein thrombosis .
spontaneous perforation of the tympanic membrane was reported for 71% ( 101/1419 ) of episodes , ranging from 21% of episodes in italy and 22% in the uk , to 48% in spain , 68% in germany and 172% in sweden . over the prospective study period ,
the overall incidence of suspected episodes was 110/1000 person - years ( 95% ci 102120 ) , and varied widely from 42 ( 95% ci 3155 ) in spain and 50 ( 95% ci 3864 ) in italy , to 135 ( 95% ci 115158 ) in sweden , 161 ( 95% ci 139185 ) in germany , and 190 ( 95% ci 160223 ) in the uk .
the results of this multi - centre cohort study confirm the relatively high burden of aom during childhood in five european countries .
the incidence of aom varied between countries , with the lowest incidence based on both the retrospective and prospective study periods occurring in italy , and the highest in spain .
overall , the incidence of aom was slightly higher in younger children ( aged 02 years ) , than in older children ( aged 35 years ) .
the incidence in our study based on the prospective period of 256/1000 person - years ( 95% ci 243270 ) is noticeably lower than the aom incidence reported in the usa and finland [ 21 , 26 ] , but is within the same range of recent estimates of aom incidence in children in europe , which ranged from 154 ( 95% ci 152158 ) to 400 ( 95% ci 397403 ) [ 27 , 28 ] .
the majority of physician - diagnosed aom in this study met the criteria for probable rather than confirmed aom .
this indicates that most of the burden of medically attended aom might be captured by records of aom diagnosis in medical charts . because parents may have used pain - relieving medications to treat fever before the aom visit , the recorded level of fever was probably underestimated , which may have resulted in an underestimate of the overall occurrence of confirmed episodes .
ear pain was the most frequently reported symptom and redness of the tympanic membrane was the sign most often seen .
the frequency of symptoms also varied between the retrospective and prospective study periods and was higher during the prospective study ( 989% vs. 876% ) , indicating that prospective data collection may be necessary to fully capture the signs and symptoms associated with aom episodes .
variations in symptoms recorded in medical charts by country suggest documentation differences by country and indicate that some medical files may be incomplete . the large size and prospective design of this study along with the well - defined criteria for confirmed and probable aom allow for a clearer understanding of the burden of aom in these five european countries and of the best way to collect information on aom in order to avoid potential underestimation and bias .
the use of a standardized protocol in each of the five countries also facilitates comparisons between countries , which is often difficult to do with published studies due to variations in study design , age groups , and data collection methods .
the approach of using varied sources of data , from historical medical charts to prospective follow - up based on both physician and parental reports , allowed us to collect data on all cases and episodes of possible aom ( suspected , probable , confirmed ) , with a holistic view to capture the entire burden of disease , considering under - reporting of undiagnosed episodes . a more specific approach , as is often taken in studies of aom , which focuses only on clinically confirmed aom , is likely to miss mild cases and episodes for which medical care is not sought .
the incidence of aom based on the retrospective study was very similar to the incidence based on the prospective study ( 268 vs. 256 ) , suggesting that in this setting , using data based on cases documented in medical charts may not lead to any major problems of underestimation vs. prospective follow - up data based on physician reports .
the incidence of suspected cases of aom based on parental reports suggests that there may be an additional 110 aom episodes per 1000 person - years which are missed when focusing only on medical attendance data .
these potentially missed events may represent less severe cases for which medical care is not sought , and are an important consideration when attempting to estimate the total incidence of aom . the difference in aom incidence in this study compared to the incidence previously reported in the usa and finland
may be explained by the fact that studies from those countries were partially conducted in a clinical trial setting where patients represent a selected group of the population followed more stringently than in our study .
the differences in aom incidence between the countries in our study may represent a combination of true differences and differences in healthcare systems , social structure , and diagnostic procedures between physicians .
the range of parent - reported incidence , which was lowest in spain and highest in the uk , may be useful in assessing the overall burden of aom and understanding true differences in incidence , as it may reflect a combination of the variable tendencies of parents to adhere to wait and watch recommendations and to consult a physician during a child 's illness .
for example , the incidence of confirmed aom in the uk was lower than in other countries , while the incidence of parent - reported aom was higher , which may suggest parents are adhering to wait and watch recommendations . in spain , which had the highest incidence of physician - diagnosed aom and lowest incidence of parent - reported aom , parents may have more access to their paediatrician due to the structure of the healthcare system and , therefore , may be more likely to bring their child in for suspected aom .
these findings are supported by a previous study which reported that parents in spain were more likely to consult a physician during a child 's illness compared to parents in the uk .
it is important to note that it is possible that not all of the parent - reported suspected episodes of aom were truly episodes of aom .
while parent - reported aom data have been shown to accurately reflect medical records , it does not necessarily mean that all suspected cases would meet the criteria for probable or confirmed aom if the child were to be examined by a physician .
however , the incidence of suspected cases still provides a valuable estimate of the burden of disease which may be missed when focusing solely on physician - diagnosed aom .
differences in healthcare - seeking behaviour by country may also explain some variation in frequency of spontaneous perforation of the tympanic membrane and ear discharge by country .
for example , in parts of sweden access to physicians is geographically limited , and there is a policy in place not to admit patients during the night for earache unless the child is aged < 1 year or is septic . a delay in treatment due to
either of these country - specific factors could contribute to the higher frequency of spontaneous perforation and ear discharge seen in sweden in this study .
for example , the later introduction of pcv7 vaccination in sweden may be associated with more aggressive pneumococcal strains than are seen in other countries where the vaccine was introduced earlier .
a limitation of the data on spontaneous perforation of the tympanic membrane is the potential misclassification which may have occurred . as spontaneous perforation of the tympanic membrane
is accompanied by ear discharge , and therefore ear discharge is often considered an indication of perforation , it is possible that there were investigator - specific differences in data recording surrounding ear discharge and perforation .
as ear discharge was noted more frequently than spontaneous perforation , perforation may be underreported in the study .
based on the available data , it is not possible to know if these differences in recording practices were variable by country .
differences in healthcare system - related characteristics and healthcare - seeking behaviour which may impact documentation , consulting and diagnostic behaviour between countries are an unavoidable limitation for this study which should be considered in interpreting results .
another limitation of this study is that the study population may have differed from the general population because of the recruitment approach .
recruited children could have been healthier due to attending regularly scheduled visits , or alternatively , they could have been more ill and therefore more likely to go to the doctor , increasing the chances of being enrolled . however , that was not the case for sweden , where mailing was used , and aom incidence in sweden was consistent with other countries .
moreover , despite efforts to document all available information regarding visits to other medical facilities for aom during follow - up , it is possible that some visits were not included and that this resulted in an underestimate of the incidence of aom .
however , parent - reported aom episodes should not be affected by this bias , since parents were instructed to report all aom episodes . in conclusion
, this study demonstrates the importance of a public health perspective , by capturing and reporting all suspected , probable , and confirmed episodes using different sources including medical charts , follow - up , and parental reports , to better understand the public health burden of aom .
differences in incidence of spontaneous perforation of the tympanic membrane by country should be examined in parallel with data on ear discharge , and may represent a combination of true differences and variability in healthcare - seeking behaviour and in diagnostic procedures by country . although it is often believed that retrospective reviews of medical charts are associated with underestimation of the burden of aom , the comparability of incidence results based on chart review vs. those based on data collected through follow - up visits suggests that a thoroughly performed chart review can deliver reliable aom incidence results . as the burden of disease is high within europe , there is a case for promoting preventative strategies for aom such as immunization .
he received institutional grants from glaxosmithkline group of companies for epidemiological studies on varicella / herpes zoster and influenza .
he received payment for participating in advisory board from glaxosmithkline group of companies , novartis , sanofi pasteur msd and astrazeneca .
he received lectures fees from glaxosmithkline group of companies , sanofi pasteur msd , astrazeneca , abbott and pfizer .
he received travel grant support for participation in congresses on infectious diseases from glaxosmithkline group of companies , sanofi pasteur , pfizer and csl behring .
s.a.s . received institutional grant from glaxosmithkline group of companies for travel to attend scientific meeting .
he received payment from glaxosmithkline group of companies for giving a lecture on pneumococcal disease .
he received payment from glaxosmithkline group of companies and astrazeneca for participation in advisory boards .
received payment from glaxosmithkline group of companies for consultancy , for given lectures and for participating in advisory board .
j.h.l . received institutional payment from the national institute for health research ( nihr ) to support costs related to recruitment of subjects and data collection . j.g.s .
m.g.s . received payment from glaxosmithkline group of companies for expert testimony and for participating in advisory boards .
she received payment from glaxosmithkline group of companies and sanofi pasteur msd for giving lectures and for development of educational presentations .
she received travel grant from glaxosmithkline group of companies for participation as a speaker at 60th congress of the spanish association of paediatrics , valladolid , 1618 june 2011 .
m.r.r . was employed by glaxosmithkline group of companies at the time the study was conducted . | summarywe conducted an epidemiological , observational cohort study to determine the incidence and complications of acute otitis media ( aom ) in children aged < 6 years .
data on physician - diagnosed aom were collected from retrospective review of medical charts for the year preceding enrolment and then prospectively in the year following enrolment .
the study included 5776 children in germany , italy , spain , sweden , and the uk .
aom incidence was 256/1000 person - years [ 95% confidence interval ( ci ) 243270 ] in the prospective study period .
incidence was lowest in italy ( 195 , 95% ci 171222 ) and highest in spain ( 328 , 95% ci 296363 ) .
complications were documented in < 1% of episodes .
spontaneous tympanic membrane perforation was documented in 7% of episodes . both retrospective and prospective study results were similar and show the high incidence during childhood in these five european countries .
differences by country may reflect true differences and differences in social structure and diagnostic procedures . |
the simultaneous occurrence of achalasia and esophageal diverticula is rare.1 there have been few reports of esophageal cancer in achalasia and esophageal diverticula .
although most patients with only esophageal diverticula are asymptomatic , patients with both achalasia and esophageal diverticula may present with dysphagia or regurgitation of food.2 additionally , the risk of esophageal cancer is increased in patients with both achalasia and esophageal diverticula .
similar to the pathogenesis of esophageal achalasia , chronic inflammation caused by repeated injury and chronic irritation by stagnated food are thought to result in esophageal carcinogenesis.3,4 there have been a few reports of esophageal cancer in achalasia with multiple esophageal diverticula .
our group published one such case report in 2009 regarding a case of achalasia associated with multiple large esophageal diverticula.5 this is a follow - up of the aforementioned case , in which esophageal carcinoma was subsequently diagnosed in the diverticula that occurred simultaneously with esophageal achalasia .
thus , barium esophagography , esophageal manometry , and esophagogastroduodenography ( egd ) were performed .
barium esophagography showed three right - sided esophageal diverticula along the mid - to - distal esophagus with achalasia ( fig .
initial esophageal manometry showed aperistalsis in the esophageal body , and each swallow resulted in simultaneous contractions ( fig .
the average peak pressure of the esophageal body was 56 mm hg as determined by conventional manometry .
therefore , the patient in this case was considered to have vigorous achalasia , defined by an average esophageal body pressure 37 mmhg , rather than the classic form of achalasia associated with lower pressures.6 his symptoms improved after botulinum toxin injection .
however , dysphagia , regurgitation of food , and epigastric discomfort recurred 5 years later .
a follow - up egd showed a slight increase in the size of the previous diverticula , mild erythematous mucosal changes , and multifocal lugol - voided lesions ( fig .
the biopsy result showed a moderate degree of epithelial dysplasia . because the lesions were located in a large and tortuous diverticulum , performing endoscopic submucosal dissection ( esd ) was considered too difficult and dangerous .
two months after pdt , egd was repeated to evaluate the response to pdt ( fig .
4 ) . mucosal nodularity was observed at a nontreated diverticulum , which on biopsy was revealed to be squamous cell carcinoma in situ ( fig .
the patient underwent an ivor - lewis esophagectomy with regional lymph node dissection for recurrent multifocal esophageal neoplasia , and the final pathologic staging was tisn0m0 ( stage 0 ) .
patients with achalasia can develop a variety of complications . among them , the most serious may be esophageal cancer .
the overall prevalence of esophageal squamous cell carcinoma in patients with achalasia has been estimated to be 3% , accounting for a 50-fold increase in cancer risk.7 in a recent , large prospective cohort study with long - term ( mean , 15 years ) follow - up data of 448 achalasia patients , the relative hazard ratio for the development of esophageal cancer in achalasia was 28.8 although many cases of esophageal carcinoma in patients with diverticula have been reported , the precise level of cancer risk in esophageal diverticulum remains to be elucidated . in both achalasia and esophageal diverticulum ,
this food and fluid stasis leads to repeated injury of the esophageal epithelium and chronically irritates the mucosal surface .
in addition , bacterial overgrowth and impaired clearance of regurgitated gastric acid contents occur during persistent esophageal distention . due to these diverse factors
, chronic inflammation may occur in the esophageal mucosa , which is presumed to develop epithelial hyperplasia , multifocal dysplasia , and finally esophageal cancer.9 before a diagnosis of cancer , the duration of symptoms is usually at least 15 years in patients with achalasia and at least 10 years in patients with esophageal diverticulum .
a large prospective cohort study was conducted with a mean follow - up period of 15 years after the onset of achalasia symptoms.8 elderly patients have an increased risk of carcinoma .
a diverticulum of less than 2 cm rarely develops into esophageal cancer.10 treatment for esophageal dysplasia or carcinoma arising from achalasia or esophageal diverticulum follows the same principles as esophageal dysplasia or carcinoma without underlying esophageal etiology .
esophageal dysplasia or early esophageal cancer can be treated by endoscopic resection , classic endoscopic mucosal resection ( emr ) , and esd , which is widely used . in the present case ,
however , the diverticula were much too large and tortuous , making emr or esd too risky ; thus , we performed an operation .
the optimal time and interval for the surveillance of patients with achalasia and/or diverticulum is open - ended .
if a patient presents with newly developed symptoms such as weight loss , melena , or hematemesis , endoscopic evaluation should be performed .
regarding achalasia , the current version of the american society of gastrointestinal endoscopy guidelines recommends that surveillance should be initiated 15 years after the onset of achalasia symptoms , although the subsequent surveillance interval is not defined . as in the present case ,
however , patients with both achalasia and diverticula should be considered for endoscopic surveillance earlier than 15 years , as the earlier development of symptoms necessitates shorter surveillance intervals.11 moreover , clinicians should consider chromoendoscopy or narrow - band image endoscopy as well as white light endoscopy for surveillance of these patients .
although the simultaneous occurrence of achalasia and esophageal diverticula is unusual , this case emphasizes the high risk of esophageal carcinoma arising from both etiologies , as well as the importance of early detection by aggressive endoscopic surveillance . | the simultaneous occurrence of achalasia and esophageal diverticula is rare . here , we report the case of a 68-year - old man with multiple esophageal diverticula associated with achalasia who was later diagnosed with early esophageal cancer .
he initially presented with dysphagia and dyspepsia , and injection of botulinum toxin to the lower esophageal sphincter relieved his symptoms .
five years later , however , the patient presented with worsening of symptoms , and esophagogastroduodenoscopy ( egd ) was performed .
the endoscopic findings showed multifocal lugol - voiding lesions identified as moderate dysplasia .
we decided to use photodynamic therapy to treat the multifocal dysplastic lesions . at follow - up egd 2 months after photodynamic therapy , more lugol - voiding lesions representing a squamous cell carcinoma in situ were found .
the patient ultimately underwent surgery for the treatment of recurrent esophageal multifocal neoplasia .
after a follow - up period of 3 years , the patient showed a good outcome without symptoms . to manage premalignant lesions such as achalasia with esophageal diverticula
, clinicians should be cautious , but have an aggressive approach regarding endoscopic surveillance . |
irritable bowel syndrome ( ibs ) is a chronic and debilitating condition , which places a significant burden on the national health service ( nhs ) , both in terms of financial cost and strain on primary and secondary care.13 the total attributable cost of ibs in the uk was almost 12 million per annum in 20122013 . despite the national institute for health and care excellence ( nice ) and british society of gastroenterology guidelines recommending that ibs management should take place within primary care,4
5 a significant proportion of patients aged 1645 years with likely ibs
research suggests that general practitioners ( gp ) still see ibs as a diagnosis of exclusion often due to uncertainty about diagnosis and in the belief that negative diagnostic tests are useful.57 overall demands for inpatient and outpatient diagnostic endoscopies are increasing steadily.1 hence , better gp education around diagnosis of ibs within primary care , along with an effective management pathway , should lead to direct nhs savings , which would allow secondary care gastroenterology services to target their resources more effectively .
in 2011 , an integrated flexible healthcare gastroenterology clinical team was created in somerset with the aim of breaking down barriers between organisations to improve patient care .
this team contained clinicians and managers from secondary care gastroenterology ( taunton and somerset nhs foundation trust , yeovil district nhs foundation trust ) community dietetics ( somerset partnership nhs foundation trust ) , gps and somerset clinical commissioning group ( sccg ) . to obtain a snapshot of the care available within gastroenterology , new outpatient slots in secondary care in taunton were audited in may 2011 to determine number of patients aged 1645 years referred from primary care with likely ibs and no alarm symptoms .
. using these audit results and extrapolating the expenditure over a 24-month period to include all patients covered by yeovil and taunton hospital catchment areas , this group of low - risk patients would have cost the nhs in excess of 161,000 .
revolving door effect of ongoing symptoms leading to repeated referral and investigation , which is well - described in ibs,9 an audit of six consecutive months ( from 1 october 2011 to 31 march 2012 ) of new patient referrals to gastroenterology secondary care outpatient clinics in taunton and somerset nhs foundation trust for those aged 1645 years with no alarm symptoms was undertaken .
this aimed to establish the percentage that had been seen in the previous 5 years , for either gastroenterology outpatient review , radiological or endoscopic investigations for the same symptoms . in 2011 ,
a community dietitian based in primary care in south somerset undertook a pilot project with patients with ibs referred directly from local gps .
this pilot study looked at outcomes using dietary intervention including the low fermentable oligosaccharides , disaccharides , monosaccharides and polyols ( fodmap ) diet.1013 for 55 patients , informal feedback data on postintervention quality of life were recorded by asking each patient , have the results of dietary intervention improved your quality of life? , with 69% ( 38/55 ) responding positively . after collecting baseline data , the focus of the future project was to empower gps to make a positive diagnosis of ibs in order to avoid secondary care referrals .
this was done by providing gps with the following :
diagnosis of ibs algorithm supplied as an innovative desktop app ( see online supplementary appendix 1).management of ibs algorithm supplied as an innovative desktop app ( see online supplementary appendix 2).county - wide gp teaching sessions led by a specialist dietitian and/or consultant gastroenterologist.provide faecal calprotectin ( fc ) testing to exclude inflammatory pathologies in patients aged 1645 years with likely ibs and thus avoiding secondary care referrals in those with fc 50 g / g.provide an innovative community - based dietetic - led gastroenterology service using dietary interventions such as the low fodmap diet for patients with ibs with no alarm symptoms , normal blood tests and fc results and intractable symptoms .
diagnosis of ibs algorithm supplied as an innovative desktop app ( see online supplementary appendix 1 ) .
management of ibs algorithm supplied as an innovative desktop app ( see online supplementary appendix 2 ) .
provide faecal calprotectin ( fc ) testing to exclude inflammatory pathologies in patients aged 1645 years with likely ibs and thus avoiding secondary care referrals in those with fc 50 g / g .
provide an innovative community - based dietetic - led gastroenterology service using dietary interventions such as the low fodmap diet for patients with ibs with no alarm symptoms , normal blood tests and fc results and intractable symptoms .
overall , the project aimed to identify those patients who despite symptoms were at low risk of pathology , and gear the focus of their management towards symptom control using specialist dietetic input to avoid expensive and unnecessary secondary care referral and investigations in a time of limited resources . the money saved by avoiding secondary care referrals and investigations would be used to fund fc testing in primary care and specialist dietetic time .
cost of new pathway with associated savings comparisons using secondary care costs based on secondary care audit data collected in may 2011 fc , faecal calprotectin ; ibs , irritable bowel syndrome ; wte , whole time equivalent . the electronic fc request form included a compulsory pop - up audit , allowing review of the indications for the test .
use of a single laboratory for fc testing rather than point - of - care testing allowed consistency of reporting and assay ( barnsley and rotherham joint pathology services using the immundiagnostik elisa test ) .
the result was returned directly to the gp as a paper copy with basic advice around levels obtained . using the laboratory reference range and based on information available in 20112012 ,
a level 50 g / g was chosen to avoid referral to secondary care.14
15 our approach was later endorsed by nice.20 first - line dietetic advice was supplied either by somerset partnership nhs trust community dietitians based within each gp practice in the county or directly by gps .
if symptoms proved intractable , then onward referral to the specialist dietitian - led gastroenterology community clinic could be made by community dietitians , gps and other community - based healthcare professionals .
secondary care teams were not given access to this clinic as the business case revolved around avoiding referral to secondary care , reinforcing to gps that ibs should be managed in primary care .
having specialist dietitians in a primary care setting was an important safety step as they were able to reassess patients for alarm symptoms and return the patient to their gp if they felt that further investigation in secondary care gastroenterology was needed .
these new specialist dietetic clinics provided the capacity to see 30 new referrals per month with each patient requiring two appointments with an 8-week gap between them .
to assess the outcomes , patients filled in symptom evaluation forms at the start and end of treatment .
the evaluation form was based on a data collection tool for assessing patient primary outcomes , using the internationally validated gastrointestinal symptom rating scale - ibs scoring system.7
16 an additional validated global symptom satisfaction question used as the current standard in ibs trials was included in the evaluation form,17 along with informal feedback data on quality of life .
sccg agreed funding in june 2012 with an initial audit planned at 1 year .
outcome data were collected for the new dietetic service from 1 may 2013 to 30 april 2016 , and analysis of fc testing ran from 1 november 2013 to 31 october 2015 .
the audit of outpatient data was repeated 10 months into the fc testing project ( august 2014 ) to inform the end of first year analysis for sccg .
the secondary care outpatient data analysis originally carried out in taunton in may 2011 ( figure 1 ) was repeated in august 2014 for taunton and yeovil to see if the pilot study using fc testing and dietetic treatment had made any difference to the use of new patient slots in gastroenterology clinics .
this analysis determined the number of relevant patients and established investigations undertaken , overall outcome and costs .
audit data for new outpatient attendances in august 2014 following gp referral at taunton and somerset nhs foundation trust ( tst ) and yeovil district nhs foundation trust ( ydh ) aged 1645 years with no alarm symptoms and likely irritable bowel syndrome ( ibs ) . a , b , c , d show outcome results for individual symptoms using gsrs - ibs scoring system and mean symptom severity scores before and after ibs dietetic management who completed treatment between 1 may 2013 and 30 april 2016 .
c and d ( n=335 ) adult patients of any age . when figures from both hospitals were extrapolated over 12 months , the total costs from these patients were approximately 120 000 , including their outpatient slot , endoscopy , radiology and serological investigations .
this was a 25% saving over baseline compared with costs from the 2011 taunton audit data of approximately 161 000 .
the overall reduction in referrals of patients aged 1645 years with likely ibs from gps to secondary care using taunton data was 36% .
the potential revolving door data collected using the audit of 6 months of new patient slots for patients aged 1645 years with likely ibs and no alarm symptoms showed that of the 117 patients fitting these criteria , 38 had been seen previously within the last 5 years for endoscopy , radiology or gastroenterology review ( 32.5% ) . over 2 years , 308 fc tests were requested by primary care as part of this project .
analysis showed that pathology was highly unlikely unless fc > 150 g / g , with no gastrointestinal pathology found at levels 50 g / g . these data should reinforce the confident use of this pathway in the future ( table 2 ) .
for those patients with fc > 50 g / g where referral did not take place , contact was made either by telephone or letter with their gp to determine their current gastrointestinal health .
this helped to educate gps and encourage them to seek a secondary care opinion if patients had fc 50 g / g and their symptoms remained troublesome .
audit results for gp requests for faecal calprotectin levels across somerset from 1 november 2013 to 31 october 2015 ( n=308 patients ) fc , faecal calprotectin ; gi , gastrointestinal ; uc , ulcerative colitis . in the case of 12 out of 13 patients with fc 50150
g / g who were not referred to secondary care , on checking with their gps , there had been no other relevant consultations and the gp added a file note to their records in each case .
our specialist community gastroenterology dietitians received their referrals from around somerset , providing clinics in four separate locations throughout the county to allow for increased patient access .
only those aged 1645 years , who had completed their dietary intervention period and who were referred specifically for management of ibs , have been included in the data ( n=146 ) .
the mean age was 32 years with 83% female predominance . using the validated global primary outcome question ,
do you have satisfactory relief from your ibs symptoms? , of those who noted
no at the initial appointment ( n=139 ) , 63% were then able to respond with
graphs a d show outcome results and mean symptom severity scores for dietetic intervention for patients referred for ibs management who had completed dietary treatment .
graphs a and b : n=146 aged 1645 years ; graphs c and d : n=335 all patients .
graph a shows that over 70% of patients reported improvement in abdominal pain and heartburn .
urgency also responded well to dietary intervention with 69% of patients reporting improvement . using the wilcoxon signed - rank test
, graph b shows that all symptoms showed a statistically significant reduction following dietetic intervention with all p values < 0.001 .
when considering the informal feedback on the improvement in quality of life , 74% ( 108/146 ) noted that dietary intervention had improved their quality of life with comments such as , this diet has turned my life around ,
i am so grateful that something has finally worked to help me. in total , the specialist dietetic clinic saw 335 patients of all ages over the data collection period and graphs c and d show results for all patients indicating similar trends to those in the age group of 1645 years .
the similarity of these data imply that ibs dietary management is effective for all age groups irrespective of the referral source , although for older patients , pathological causes of their symptoms would need ruling out by endoscopic or radiological means .
despite the 2008 ibs nice guidance , research shows that referrals of patients with ibs to secondary care are steadily increasing at a national level.1
5 however , by using cost - effective patient - focused care , this pathway has managed to reverse that trend with a reduction in combined referrals and costs in two district general hospitals .
while many centres have focused on using fc to triage secondary care referrals after outpatient review , we understand that this is the first pathway which has piloted the funding of gp education , aided diagnosis by using fc to exclude inflammatory pathology , provided an effective treatment plan and used the cost savings which have been realised across an integrated healthcare community to fund specialist dietetic services based in the community .
while the 2008 nice report highlighted that ibs should be managed within primary care , they also noted that healthcare professionals would need to be appropriately trained in ibs diagnostic criteria , if the guidance was to be successfully implemented.5 hence , the focus of the somerset project was to educate gps and to give them the necessary tools to help their patients with ibs .
as this project has taken several years of negotiation and a business case to reach the project stage from its initial inception in 2011 , more uk data are now available regarding the use of fc to reduce unnecessary referral and investigation where the result is likely to be negative.18
19 what is reassuring is that subsequent nice advice ( dg11 ) has validated our initial chosen cut - off level for fc to rule out inflammatory disease ( < 50 g / g).20 while use of fc reduces unnecessary endoscopic investigations , for those patients who are referred with fc levels of 50150 g / g , there is still a low likelihood of pathology and in these cases , an outpatient review can determine the right course of action .
an alternative approach which is supported by recent evidence , is to repeat the fc for equivocal cases in 68 weeks and refer only if the result remains elevated.21 other areas have found that with time gps tend to extend their use of the fc test to include patients where they would otherwise have been happy to make a clinical diagnosis , potentially negating any financial benefits.18 to counteract this in somerset , we have insisted that fc should be used only if the patient is aged between 16 and 45 years , with no alarm symptoms and would otherwise be referred to secondary care .
all referrals require completion of a pop - up gp audit form in order to obtain authorisation and ongoing gp education is essential .
dietetic outcomes were encouraging and our data have contributed to kings college london research in long - term outcomes , where it has been shown that 70% of patients continue to have satisfactory relief 618 months postdischarge.22 nevertheless , there will be a significant number of patients who do not respond to dietary and lifestyle measures for a variety of reasons .
we have made basic suggestions about using medication in our management of ibs pathway ( see online supplementary appendix 2 ) .
however , we should consider hypnotherapy and cognitive behavioural therapy within this pathway as a future development as these have been endorsed by the nice clinical guideline 61 published in 2015.12 these were not included in our initial pathway as their availability was limited in somerset and would have required additional funding and appointment of new staff . since 2012 , we have received over 35 enquiries from across the uk from other primary and secondary care teams to find out how this project was set up and funded both for the specialist dietetic clinic and the overall pathway .
in august 2014 , a survey ( n=31 ) of those making enquiries revealed that despite using our data to make a strong business case , only 12 were offering a dedicated ibs dietetic service with just 6 of these being established as a specialist dietetic - led community gastroenterology clinic .
interestingly , 46% of the present or planned dietetic services were to be placed within secondary care which may negate any cost - efficiency benefit as secondary care referral may raise expectations around investigation and medical review in outpatients .
one of the strengths of our project was to avoid referral into secondary care to prevent this happening .
for those centres without a service , 92% cited lack of funding as the main obstacle , while 29% cited lack of secondary care support amid concerns about missing underlying pathology such as cancer and losing money from secondary care services to provide funding.23 the pathway used in somerset was established in the knowledge that there is a general community dietitian in every gp practice in the county .
hence , to gatekeep referrals into the specialist gastroenterology dietetic service , first - line advice was given by these general community dietitians or gps themselves .
however , it is acknowledged that the situation may differ in other areas of the uk and hence the pathway may need to be altered according to local needs .
indeed , first - line advice could be given in dietitian - led group sessions , or gps can use the british dietetic association ibs first - line information sheet , which is endorsed by nice and is freely available on the internet.24 overall , the suspicion that in 2011 our secondary care outpatient clinics were not effectively managing symptoms with little reassurance or lasting benefit from normal test results was confirmed by an appreciable revolving door effect which necessitated a new approach .
this ibs pathway was set up as a pragmatic way to manage increasing demand for secondary care services , by providing an alternative cost - effective patient - centred solution .
our model highlights that there is no single solution to ibs and that it is essential to have the multidisciplinary approaches of effective dietetic intervention , reliable faecal biomarkers and gp education in order to encourage long - term and effective patient self - management . with this combination
it is possible to have a successful and cost - effective pathway , which delivers significant nhs savings and also high levels of patient satisfaction in a community setting while allowing secondary care gastroenterology services to target their resources more effectively . in 2008 ,
the national institute for health and care excellence clinical guideline 61 advised that irritable bowel syndrome ( ibs ) diagnosis and management should take place in primary care ; however , referrals to secondary care have continued to rise for patients with likely ibs despite a low probability of finding pathology if investigations are carried out .
the low fodmap diet has gained increasing credibility for managing ibs symptoms , when provided by specifically trained dietitians . providing general practitioners ( gp ) education along with diagnosis and management pathways can lead to a reduction in secondary care referrals .
dietary intervention works to significantly reduce all ibs symptoms in patients of all ages when advice is given by appropriately trained dietitians .
supply gp with an alternative pathway for patients with ibs to help reduce secondary care referrals .
encourage the use of audited faecal calprotectin testing as a reliable tool within primary care when ruling out inflammatory bowel disease in patients aged 1645 years with likely ibs and no alarm symptoms .
encourage the use of primary care - based specialist dietetic intervention for patients with ibs .
encourage clinical commissioning group to set up ibs management within primary care to prevent unnecessary secondary care referrals and investigation and thus reduce national health service costs .
in 2008 , the national institute for health and care excellence clinical guideline 61 advised that irritable bowel syndrome ( ibs ) diagnosis and management should take place in primary care ; however , referrals to secondary care have continued to rise for patients with likely ibs despite a low probability of finding pathology if investigations are carried out .
the low fodmap diet has gained increasing credibility for managing ibs symptoms , when provided by specifically trained dietitians .
providing general practitioners ( gp ) education along with diagnosis and management pathways can lead to a reduction in secondary care referrals .
dietary intervention works to significantly reduce all ibs symptoms in patients of all ages when advice is given by appropriately trained dietitians .
supply gp with an alternative pathway for patients with ibs to help reduce secondary care referrals .
encourage the use of audited faecal calprotectin testing as a reliable tool within primary care when ruling out inflammatory bowel disease in patients aged 1645 years with likely ibs and no alarm symptoms .
encourage the use of primary care - based specialist dietetic intervention for patients with ibs .
encourage clinical commissioning group to set up ibs management within primary care to prevent unnecessary secondary care referrals and investigation and thus reduce national health service costs . | backgroundirritable bowel syndrome ( ibs ) costs the national health service almost 12 million per annum . despite national guidelines advising primary care management ,
these have failed to stem secondary care referrals of patients with likely ibs for unnecessary and costly assessment and investigation without necessarily achieving resolution of their symptoms.methodsin 2011 , an integrated team from primary and secondary care developed a business case using baseline data to create a somerset - wide ibs pathway using clinical commissioning group funding .
this provided face - to - face general practitioners ( gp ) education , developed a diagnostic pathway and funded faecal calprotectin ( fc ) testing to exclude inflammatory pathology for patients aged 1645 years with likely ibs and no alarm symptoms . for those with fc50 g / g
, we provided a management algorithm and community - based dietetic treatment .
audit results measured usage and outcomes from fc testing , changes in patterns and costs of new patients reviewed in gastroenterology outpatients and dietetic ibs treatment outcomes.resultsthe proportion of new patient slots used reduced from 14.3% to 8.7% over 10 months while overall costs reduced by 25% for patients with no alarm symptoms and likely ibs aged 1645 years .
fc results confirmed research findings with no inflammatory pathology , if fc50 g / g over 2 years .
63% of patients had satisfactory control of their ibs after specialist dietetic input with 74% reporting improved quality of life.conclusionsthe combination of gp education , providing diagnosis and management pathways , using fc to exclude inflammatory pathology and providing an effective treatment for patients with likely ibs appeared successful in our pilot .
this proved cost - effective , reduced secondary care involvement and improved patient care . |
a 23-year - old indian female presented to a tertiary institute of northeast india with the chief complaints of dimness of vision , pain and redness in the right eye ( od ) for 3 months .
the patient was previously treated elsewhere with two posterior sub - tenon injections of triamcinolone acetonide given 6 weeks apart .
ocular alignment was normal with a visual acuity of counting finger at 3 m in the od .
there was minimal sclerouveitis noted in the inferior - temporal quadrant of od . on slit - lamp examination
, od showed 360 posterior synechiae with anterior chamber flare and cells ( + + + ) with 1 mm hypopyon [ fig .
there was a suspected mass in the inferior - temporal quadrant behind the iris , pushing it anteriorly .
( a ) slit - lamp photograph of anterior chamber of right eye showing hypopyon with anterior chamber reaction ( flare + + + , cells + + + ) ; ( b and c ) the lesion in the ciliary body region of right eye in t2-weighted image of magnetic resonance imaging in coronal and axial planes , respectively .
imaging gave the probable diagnosis of ciliary body melanoma b - scan ultrasound ( b - scan usg ) of od was suggestive of ciliary body mass with adjoining exudative retinal detachment ( erd ) .
usg bio - microscopy findings were consistent with the findings of b - scan usg .
the patient was advised with complete blood count with peripheral blood smear which was within normal limit .
syphilis screening ( venereal disease research laboratory ) was nonreactive with normal thyroid function test and negative mantoux test ( 5tu ) reading .
based on the clinical examination and baseline investigations , we came to the differential diagnosis of ciliary body melanoma or similar tumors .
after obtaining informed consent , enucleation was carried out in od , and eyeball specimen was sent to ocular pathology laboratory for histopathological analysis . in grossing , there was a grayish - white - colored tumor seen in the inferior - temporal part of the ciliary body measuring ( 10.99 7.98 ) mm . adjoining the grayish - white ciliary body mass , there was an erd noted [ fig . 2 ] .
gross photograph of eyeball showing grayish - white mass in the ciliary body region with gross thickening of ciliary body and adjoining exudative retinal detachment microscopic description of enucleated eyeball showed peripheral corneal vascularization .
an eosinophilic mass was seen in the ciliary body with diffuse plasmacytoid cells , with reactive lymphoid follicle and other inflammatory cells [ fig .
( a ) plasmacytoid cells ( h and e , 200 ) ; ( b ) exudation in anterior chamber ( 200 ) ; ( c ) the scleral vascularization with inflammatory cells ( 400 ) ; and ( d ) the eosinophilic exudation of the adjoining exudative retinal detachment ( 200 ) ihc for both kappa and lambda was positive .
ihc for igg4 was positive in occasional cells which also expressed cd138 ( plasma cells ) .
nearly , 30% of all the cd138 positive plasma cells were found to be igg4-positive [ fig . 4 ] .
please note that the immunoglobulin g4 positivity was around 30% of total cd-138 plasma cells positivity .
negative control slide did not show immunostaining protein chemistry revealed hypergammaglobulinemia with higher levels of total protein and gamma fraction .
a hematologist was consulted , and bone marrow examination revealed mild anemia , for which she was given supportive treatment . in the postoperative period ,
on follow - up at 6 weeks , she was given prosthesis in od , and the patient was doing well till her last review .
protein chemistry revealed hypergammaglobulinemia with higher total protein ( 8.5 g / dl ; normal 6.48.2 g / dl ) and gamma fraction ( 2.06 g / dl ; normal 0.911.71 g / dl ) .
igg4-rd is a systemic condition characterized by tissue igg4-positive lymphoplasmacytic infiltrative lesions in the body with high serum level of igg4 .
it was initially found that mikulicz 's disease was related with igg4-rd and later established that this condition can occur in any of the ocular adnexal tissue .
the median age of patients with igg4-rd was 59 years ( varies from 30 to 86 years ) , and almost equal preponderance was found in both sexes .
igg4-rd is a recently proposed clinical entity with varied clinical features , but its pathogenesis remains to be understood clearly .
after enucleation , on histopathology , plasma - lymphocytic inflammations were noted in iris and ciliary body region .
on ihc , plasmacytoma was ruled out due to polyclonality in kappa and lambda light chain positivity .
bone marrow examination did not show any other abnormality , consistent with the pathology discussed here .
review of literature showed that igg4-rd occurs in orbit and adnexal tissue in older age group .
our present understanding of ophthalmic igg4-rd having several unique characteristic is limited to orbital and adnexal tissues . to the best of our knowledge ,
this is the first described igg4-rd in intraocular structures mimicking as a ciliary body melanoma .
this study was funded by sri kanchi sankara health and educational foundation , guwahati , india .
this study was funded by sri kanchi sankara health and educational foundation , guwahati , india .
| immunoglobulin g4 ( igg4-related diseases ) affects various tissues and organs of the human body .
orbital , adnexal , and scleral inflammations were already reported in the medical literature . to the best of our knowledge , we report the first case of intraocular igg4-associated inflammatory mass in the ciliary body mimicking as a melanoma in a 23-year - old female from northeast india .
characteristic histopathology , immunohistochemistry in the tissue , protein chemistry , and raised serum igg4 were supportive for the diagnosis .
as this newly diagnosed disease has multi - organ affection and little is known about its pathogenesis particularly in eye and adnexa , the present case will open many challenges in clinico - pathological diagnosis and research in the future . |
in europe , the incidence of nosocomial urinary tract infections ( utis ) associated with the presence of indwelling urinary catheters ( cautis ) accounts for 3.55 per 1000 hospitalised patient - days with an important impact on public health costs . moreover , the presence of indwelling urinary catheter is a risk factor for development of symptomatic urinary tract infections .
in fact , from 10% to 30% of patients with indwelling urinary catheters develop symptomatic utis .
recently , the research 's attention is focused on the role of bacterial biofilms in the development of cautis and utis .
biofilm formation plays an important role in the field of urology , due to its development on the surface of indwelling urinary catheters and ureteral stents and the subsequent infection , often with antibiotic resistance and development .
the microbial biofilm capacity to adhere on urinary catheter is due to its feature : a structured community of microorganism , with an extensive exopolymer matrix ( slime ) protecting the microbial cells against unfavourable environmental factors [ 5 , 6 ] .
several methods have been purposed to prevent biofilm formation in the urinary tract , that is , antibiotic - impregnated catheters , silver hydrophilic coating , heparin coating , and triclosan , since these devices seem to not be able to improve clinical symptoms or to decrease the antibiotic use .
plants extracts are often used in urology to treat the utis , particularly the recurrent forms .
the idea is to prevent the adhesion of bacteria on urinary tract mucosa , in particular the bladder mucosa , and to avoid the biofilm formation , which are the key of recurrent utis development .
recently , cai and coworkers demonstrated that the use of plants extracts resulted in a significant reduction of microbial colonization in patients with indwelling urinary catheters . in this study , we focused our attention on umbelliferone ( 7-hydroxycoumarin ) , arbutin , and n - acetylcysteine . in our study , umbelliferone was isolated from herniaria hirsuta ( caryophyllaceae ) , a flowering plant , native to eurasia and north africa , used in folk medicine as a diuretic and to treat kidney stones .
several authors showed that the extract of herniaria hirsuta may contain substances that inhibit calcium oxalate crystal aggregation and might be beneficial in preventing kidney stone formation .
the idea to use umbelliferone in this study is based on the hypothesis that it is able to reduce the biofilm formation by preventing the biofilm core enucleation . on the other hand , arbutin , the active principle of bearberry ,
finally , several studies showed that n - acetylcysteine ( nac ) is able to decrease biofilm formation by reducing the production of extracellular polysaccharide matrix and promoting the disruption of mature biofilm . based on these previous evidences , this preliminary
was aimed at evaluating in vitro efficacy of different mixtures containing umbelliferone , arbutin , and n - acetylcysteine to decrease microbial colonization and biofilm development .
the study took place between january and march 2014 using a modified method described by kuhn et al . and mazzoli . in the first month
the following two months were devoted to biofilm development , data collection , and results analysis .
a single wild strain of enterococcus faecalis ( previously isolated from a patient with uti as described by mazzoli ) was used during the whole study .
the strain was identified and characterized biochemically using the species identification cards of the vitek ii semiautomated system for microbiology ( biomrieux ; bd , italy ) .
antibiotic sensitivity was assayed on different antibiotic cards of the vitek ii ( biomrieux ; bd , italy ) and minimum inhibitory concentration and multidrug resistant break points recommended by clinical and laboratory standards institute were used .
the enterococcus faecalis strain , used in this experiment , showed resistance to the following antimicrobial agents : ciprofloxacin , cotrimoxazole , levofloxacin , and sulfamethoxazole .
the proximal 5 cm long segment of each catheter was aseptically separated with a sterile scalpel ( figure 1 ) .
separated bioreactors were set up for each catheter segment during the experimental phase according to the following procedure .
the catheter segment was put in a falcon tube ( falcon brand products ; life sciences brands ) and 40 ml of e. faecalis suspension ( 5 10 colony - forming units ( cfu)/ml ) in mueller - hinton broth ( sigma - aldrich co. , llc . ,
then , 5 ml of different solutions was poured in each bioreactor , according to the following experimental groups : control group : 0.9% sterile saline .
group 1 : aqueous solution containing umbelliferone ( 150 mg ) , arbutin ( 60 mg ) , and n - acetylcysteine ( 150 mg ) .
group 2 : aqueous solution containing umbelliferone ( 150 mg ) , arbutin ( 60 mg ) , and n - acetylcysteine ( 400 mg ) .
group 3 : aqueous solution containing umbelliferone ( 300 mg ) , arbutin ( 60 mg ) , and n - acetylcysteine ( 150 mg ) .
control group : 0.9% sterile saline . group 1 : aqueous solution containing umbelliferone ( 150 mg ) , arbutin ( 60 mg ) , and n - acetylcysteine ( 150 mg ) .
group 2 : aqueous solution containing umbelliferone ( 150 mg ) , arbutin ( 60 mg ) , and n - acetylcysteine ( 400 mg ) .
group 3 : aqueous solution containing umbelliferone ( 300 mg ) , arbutin ( 60 mg ) , and n - acetylcysteine ( 150 mg ) .
after incubation , the amount of planktonic microbial cells in the incubation medium was evaluated by plating aliquots on solid growth medium .
cfu were enumerated after 24 h and expressed as cfu / ml of incubation medium , in agreement with previous paper .
the remaining incubation medium was discarded and each catheter segment was used for the quantification of sessile bacteria as previously described . briefly , after gentle washing in sterile saline , all collected catheter segments were placed in 5 ml of 0.9% sterile saline solution and sonicated for 15 min to release bacterial cells from the biofilm adhering to the catheter surface .
the resulting suspension was quantitatively cultured on solid medium to quantify the amount of e. faecalis cells in the biofilm .
the main outcome measure was the amount of cfu / cm , as an indicator of the quantity of biofilm formed on the catheter surface at the end of the incubation period .
the rationale behind the choice of e. faecalis for this experiment is two main points : first , e. faecalis is one of the most common causes of nosocomial infections and an important etiological agent of cautis ; second , e. faecalis is frequently a strong biofilm producer , strongly adhering to the surface of the urinary catheter establishing persistent uti .
a 5 cm long segment from the tip of the catheter was used for microbiological analysis and biofilm evaluation .
quantitative assessment of slime production was performed using crystal violet binding assay method according to the christensen microwell assay .
optical density ( od ) measurements , read by a microreader apparatus ( eti - system s800 , diasorin , italy ) at 630 nm with the photometer switched to the single - wave length mode , were performed in triplicate and averaged .
the n - acetyl - l - cysteine used in this experiment has been obtained from giusto faravelli spa , milan , italy .
we used the agropyron repens extract , 20% arbutin ( hplc ) , produced in china and imported from l.c.m .
moreover , the herniaria hirsuta extract was produced in north europe and imported from solim s.r.l .
, reggio emilia , italy . median and interquartile ranges ( iqrs ) for quantitative cultural data were computed .
the amount of planktonic ( cfu / ml ) and sessile ( cfu / cm ) bacteria was compared among the experimental groups by using a kruskal - wallis test .
moreover , wilcoxon rank - sum tests were used for pairwise comparisons and the levels of post hoc pairwise comparisons were adjusted using a sequential bonferroni adjustment . the threshold for statistical significance was set at p < 0.05 .
spss 11.0 software ( spss inc . , chicago , usa ) was used for the statistical analyses .
we defined this study as exploratory ; therefore we did not determine a power calculation .
, we documented a significant development of enterococcus faecalis biofilm both in inoculation medium and on catheter surface . in the medium we documented 10 cfu / ml development of the strain , while on the catheter surface we found 3.69 10 median cfu per 1 cm catheter segment ( iqrs : 2.28 ) .
the 5 catheter segments of the control group showed 10 cfu / ml in the incubation medium development of the strain while on the catheter surface we found 3.69 10 median cfu per 1 cm catheter segment ( iqrs : 2.28 ) .
results of the cultural analysis at the start and at the end of the incubation period are summarized in table 1 .
initial planktonic load was 10 cfu / ml in all groups . at the end of the incubation period , the planktonic load was 10 cfu / ml for the control group .
conversely , 10 cfu / ml were found in group 1 and group 2 .
a significant reduction ( p < 0.001 ) in the planktonic load with respect to control was found in group 3 , showing < 10 cfu / ml .
similarly , we found differences in the amount of sessile bacteria retrieved from the biofilm formed on catheter surface .
results of the sessile bacterial load at the end of the incubation period are summarized in table 2 . from the surface of catheter segments
we retrieved a median ( interquartile range ) number of cfu / cm of 1.67 10 ( 1.33 10 ) and 1.49 10 ( 0.73 ) in groups 1 and 2 , respectively . on the other hand , in group 3
, we note a statistically significant reduction ( p = 0.004 ) in sessile bacterial load between group 3 ( 0.12 10 cfu / cm ) and control group .
the majority of utis are associated with the presence of indwelling urinary catheters ( cautis ) and are related with the presence of microbial biofilm colonization [ 6 , 18 ] .
the reduction of microbial biofilm development on urinary catheter could be the key in order to avoid cautis .
several clinical strategies have been proposed and tested to prevent biofilm formation , with divergent results . moreover , the use of antibiotic in prophylaxis or in therapy after catheter substitution is a dangerous practice that is paralleled by a growing frequency of multidrug resistant pathogenic strains [ 19 , 20 ] .
our preliminary findings show that the use of mother tincture of umbelliferone isolated from herniaria hirsuta 300 mg , arbutin 60 mg extracts , and n - acetylcysteine 150 mg resulted in a significant reduction of microbial colonization and biofilm development on the surface of urinary catheter .
this preliminary data , if supported from other in vitro and in vivo tests , could address the development of new strategies for the prevention of biofilm formation on urinary catheters , thus contributing to the management and reduction of cautis .
the latest cochrane review evaluated the influence of the type of indwelling catheter on the development of urinary tract infection in 12,422 hospitalised adults in 25 parallel group trials and 27,878 adults in one large cluster - randomised crossover trial who undergo short - term urinary catheterization .
the authors reported that silver alloy - coated catheters were not associated with a statistically significant decrease in symptomatic cauti .
in particular , authors highlight that nitrofurazone - impregnated catheters reduced the risk of symptomatic cauti and bacteriuria , although the magnitude of this reduction was low and hence may not be clinically relevant .
the use of silver alloy - coated catheters or antibiotic - impregnated catheters does not represent the optimal solution for the cauti prevention .
recently , cai et al . documented the efficacy of preparation with solidago , orthosiphon , birch , and cranberry extracts to decrease the incidence of positive urine cultures and a lower amount of biofilm on catheter lumen surface in patients with indwelling urinary catheter .
they highlight that the effectiveness of this treatment is due to the specific characteristics of each component , suggesting that the combination of these components can amplify the effect of each one .
several authors demonstrated the in vitro efficacy of arbutin and its metabolite hydroquinone against a variety of bacterial strains [ 11 , 22 , 23 ] .
moreover , the efficacy of an oral administration of a single dose of arbutin to inhibit the bacterial growth in urine has been described for the first time in 1970 . furthermore , schindler et al . demonstrated that , after oral administration , arbutin is excreted in the urine at the site of action as hydroquinone glucuronide , hydroquinone sulfate , and hydroquinone .
this aspect is very important in order to plan an in vivo study for testing the efficacy of this compound in patients with indwelling catheter .
the other compounds ( n - acetylcysteine and mother tincture of umbelliferone isolated from herniaria hirsuta ) are not yet tested in patients with urinary tract infections but they have specific characteristics that can be useful for the bacterial biofilm prevention .
n - acetylcysteine has been purposed as a mucolytic agent , due to the fact that it is able to dissociate mucin disulphide bonds and other disulphide bond cross - linked gel components to reduce viscosity .
evaluated the effect of ciprofloxacin and n - acetylcysteine alone and in combination against biofilm production and/or preformed mature biofilms on ureteral stent surfaces . using a standard microbiological analysis and scanning electron microscopy analysis , these authors demonstrated that ciprofloxacin / n - acetylcysteine combination showed the highest inhibitory effect on biofilm production and the highest ability to eradicate preformed mature biofilms .
previously several studies showed that umbelliferone exerts anti - inflammatory , antioxidant , antidiabetic , antinociceptive , and anticancer effects .
moreover , the effects of umbelliferone on bacteria have been also reported [ 2830 ] .
using salmonella enterica serovar typhimurium infection in mice , documented that 7-hydroxycoumarin pretreatment is able to reduce both tissue damaging and immunosuppressive effects of the oxidative stress related to the infection .
lee and coworkers showed that umbelliferone is able to inhibit biofilm e. coli o157:h7 formation by more than 80% . here , we demonstrated for the first time that umbelliferone at the high dose ( 300 mg ) is able to reduce the bacterial growth and biofilm production probably through its ability to induce both biofilm core enucleation and diuresis .
the first limitation is the limited number of enrolled catheters , due to the study 's exploratory design .
the second limitation is the difficulty of evaluating the efficacy of each compound in decreasing biofilm formation .
however , given the fact that bacterial resistance to antibiotics has been increasing , we would like to stress the fact that there is a growing necessity to develop new treatments to reduce catheter bacterial colonization .
the use of mother tincture of umbelliferone 300 mg , extracted from herniaria hirsuta , arbutin 60 mg , and n - acetylcysteine 150 mg is able to reduce e. faecalis colonization and biofilm development on the surface of urinary catheter .
these preliminary findings can be the basis for clinical studies in patients with indwelling catheter to reduce incidence of utis , to reduce the costs for healthcare structures , and to improve the safety of treatment reducing the development of side effects and drug - drug interactions , particularly in elderly patients . | we evaluated , in a preliminary study , the efficacy of umbelliferone , arbutin , and n - acetylcysteine to inhibit biofilm formation on urinary catheter .
we used 20 urinary catheters : 5 catheters were incubated with enterococcus faecalis ( control group ) ; 5 catheters were incubated with e. faecalis in presence of umbelliferone ( 150 mg ) , arbutin ( 60 mg ) , and n - acetylcysteine ( 150 mg ) ( group 1 ) ; 5 catheters were incubated with e. faecalis in presence of umbelliferone ( 150 mg ) , arbutin ( 60 mg ) , and n - acetylcysteine ( 400 mg ) ( group 2 ) ; and 5 catheters were incubated with e. faecalis in presence of umbelliferone ( 300 mg ) , arbutin ( 60 mg ) , and n - acetylcysteine ( 150 mg ) ( group 3 ) .
after 72 hours , planktonic microbial growth and microorganisms on catheter surface were assessed . in the control group , we found a planktonic load of 105 cfu / ml in the inoculation medium and retrieved 3.69 106 cfu / cm from the sessile cells adherent to the catheter surface . a significantly lower amount in planktonic ( p < 0.001 ) and sessile ( p = 0.004 ) bacterial load was found in group 3 , showing < 100 cfu / ml and 0.12 106 cfu / cm in the incubation medium and on the catheter surface , respectively .
in groups 1 and 2 , 1.67 106 cfu / cm and 1.77 106 cfu / cm were found on catheter surface . our results document that umbelliferone , arbutin , and n - acetylcysteine are able to reduce e. faecalis biofilm development on the surface of urinary catheters . |
talking about health inequality in public health implicitly denotes socioeconomic inequality in health(1 ) . to acknowledge the importance of striving for equity in particular health equity- , it is necessary to know how extensive the differentials in health and its determinants globally are . in every part of the world , and in every type of political and social system
, differences in health have been noted between different social none in the population and between different geographical areas in the same country ( 2 ) .
studies over the past decades have consistently shown inequalities in health status among socioeconomic none , gender , ethnicity , geographical area and other measures associated with social determinates , which adversely influence health ( 3 - 5 ) .
social determinants such as occupation , education , life style , basic amenities , house overcrowding and in general terms , economic circumstances affect the health of the population in different generations over decades(6 ) .
income inequality has been shown that correlates with health status in different countries ( 8) .
the way in which health inequality has customarily been documented is by comparing differences in the average health across none , for example , by sex or gender , income , education , occupation , or geographic region . in the controversial world health report 2000 , ( 9,10 )
researchers at the world health organization criticized this traditional practice and proposed to measure health inequality across individuals irrespective of individuals ' group affiliation ( 11 ) .
there is consistent evidence that disadvantaged none have poorer survival chances , dying at a younger age than more favoured none .
for example , a child born to professional parents in the united kingdom , was expected to live over 5 years longer than a child born into an unskilled manual household ( 12 ) . according to the final report by the commission on social determinants of health ( csdh ) , in japan or sweden people can expect to live more than 80 years ; in brazil , 72 years
; india , 63 years ; and in one of several african countries , fewer than 50 years , while within countries differences in life expectancy are dramatic and are seen worldwide ( 13 ) . in france ,
the life expectancy of a 35 year old university lecturer is 9 years more than that of an unskilled manual worker of the same age ( 2 ) . in hungary
, the budapest mortality study found that males living in the most depressed neighborhoods had a life expectancy of about 4 years less than the national average , and 5 years less than those living in the most fashionable residential district ( 14 ) . in spain ,
twice as many babies die among families of rural workers as among those of professionals ( 2 ) . in iran ,
infant mortality rate in poor provinces was 2.34 times more than affluent areas in 2005 ( 15 ) .
social determinants of health refer to a wide range of factors not limited to social component ; arising from economic , cultural , educational , political or environmental problems .
this inclusive definition of sdh was the cornerstone of our conceptual framework which led to 65 indicators in six policy domains of urban heart ( 16 ) .
sdh refers to both specific features and pathways by which societal conditions affect health and that potentially can be altered by informed action ( 17 ) .
csdh called for closing the health gaps in a generation , in its final report in 2008 , emphasizing on primary health care ( phc ) approach ( 13 ) which was acknowledged in a large gathering by who in october 2011 which in turn led to rio declaration ( 18 ) .
health equity or inequality ?
equal worth of all people is acknowledged in the religious beliefs and also is a universally accepted idea ( 19 ) , while health has a particular value for all individuals and could be assumed as one of the core principles of human right , which has been declared by who ( 20 ) .
inequity and inequality in health is rather a philosophic and moral dilemma ( theories of justice and society ) ( 21 ) .
health equity has been defined as : the absence of systematic disparities in health ( or its determinants ) between more and less advantaged social none in terms of wealth , power and prestige ( 22 ) .
additional considerations such as preventability or necessity have been proposed to judge whether a difference is inequitable , i.e. a difference could be considered inequitable if the factor is avoidable or it is not necessary ( 2 ) .
however even highly risky behavior such as sky diving could be avoided ; therefore the tragic outcome might not be inequitable ( 21 ) .
on the other hand there are viewpoints indicating that risk taking behaviors revolve around individuals free will , free choice and their own responsibility , which may not be supposed as unfair ; while these risk taking behaviors such as physical inactivity , smoking or addiction are consequences of social disparities and unequal opportunities enrooted in socio - economic determinants of health .
we have numerous examples of health inequalities in our experience ( urban heart ) , which could be assumed as unfair and consequently inequity .
health actions should be directed , at least in part , towards eliminating inequities in health .
whatever we take as theoretical basis , underlying principles or different wordings , all is about injustice ( 20 ) . to tackle the main controversies and challenges regarding the
disparities and health inequalities mainly affect socially disadvantaged none , who should be targeted in a balanced and sustainable urban planning . presenting the health and sdh inequalities ( as matrices ; see below ) to policy makers , practitioners , mayors , city governors , different sectors in the city , and the community , will make sufficient motive among all parties to reduce the inequalities
.
measuring inequalities in health and its social determinants ( sdh ) is prerequisite for any master plan for healthy and sustainable cities .
urban health equity assessment and response tool ( urban heart ) was originally developed by the who kobe centre ( wkc : who centre for health development ) as a user - friendly guide for local and national officials to identify health inequities and plan actions to reduce them .
urban heart was pilot tested in tehran in 2008 and officials from 60 countries including 22 countries in eastern mediterranean region have been trained to employ this user - friendly guide so far .
urban heart seeks to give policy and decision makers at national and local levels , to :
identify the differences between the health , health determinants and well being of people living in disadvantaged urban areas and the general population ; and
determine appropriate , feasible , acceptable , and cost - effective strategies , interventions and actions which should be used to reduce inequity gaps between people living in the same city .
employing urban heart may have several bi - products for different parties such as determining a unique index to measure inequities for policy makers , identifying current gaps and relationship to other indices for public health practitioners , and empowering interested parties including community - based organizations , state or councils at localities , and ordinary dwellers .
urban heart is rather a strategic approach to define and track equity and health equity in urban settings .
the urban heart has a health equity assessment component to measure the equity , and a response component that encourage urban local governments to employ the best approaches to fill the existing gaps .
the former component assists the authorities in cities conduct a systematic assessment of unfair health conditions in the urban setting . to do this
, it stimulates users to think about the equity aspect of indicators .
for ease of analysis , the tool suggests reviewing evidence within four major policy domains including physical environment and infrastructure , social and human development ,
governance. these policy domains were extended to six in tehran model , where health and nutrition , and also
the health equity component also has a monitor ( for trend ) and a matrix ( to compare different locations ) that enable policy and decision makers to plot out health indicators ( e.g. percentage of households with access to safe water ) in such a way that a quick comparison can be made between the city and country ( and ultimately global or international standards ) and the extent of difference between disadvantaged city areas , the rest of the city and the country average , which provides sufficient evidence for decision making .
there is consistent evidence that disadvantaged none have poorer survival chances , dying at a younger age than more favoured none .
for example , a child born to professional parents in the united kingdom , was expected to live over 5 years longer than a child born into an unskilled manual household ( 12 ) . according to the final report by the commission on social determinants of health ( csdh ) , in japan or
sweden people can expect to live more than 80 years ; in brazil , 72 years ; india , 63 years ; and in one of several african countries , fewer than 50 years , while within countries differences in life expectancy are dramatic and are seen worldwide ( 13 ) . in france ,
the life expectancy of a 35 year old university lecturer is 9 years more than that of an unskilled manual worker of the same age ( 2 ) . in hungary
, the budapest mortality study found that males living in the most depressed neighborhoods had a life expectancy of about 4 years less than the national average , and 5 years less than those living in the most fashionable residential district ( 14 ) . in spain , twice as many babies die among families of rural workers as among those of professionals ( 2 ) . in iran ,
infant mortality rate in poor provinces was 2.34 times more than affluent areas in 2005 ( 15 ) .
social determinants of health refer to a wide range of factors not limited to social component ; arising from economic , cultural , educational , political or environmental problems .
this inclusive definition of sdh was the cornerstone of our conceptual framework which led to 65 indicators in six policy domains of urban heart ( 16 ) .
sdh refers to both specific features and pathways by which societal conditions affect health and that potentially can be altered by informed action ( 17 ) .
csdh called for closing the health gaps in a generation , in its final report in 2008 , emphasizing on primary health care ( phc ) approach ( 13 ) which was acknowledged in a large gathering by who in october 2011 which in turn led to rio declaration ( 18 ) .
health equity or inequality ?
equal worth of all people is acknowledged in the religious beliefs and also is a universally accepted idea ( 19 ) , while health has a particular value for all individuals and could be assumed as one of the core principles of human right , which has been declared by who ( 20 ) .
inequity and inequality in health is rather a philosophic and moral dilemma ( theories of justice and society ) ( 21 ) .
health equity has been defined as : the absence of systematic disparities in health ( or its determinants ) between more and less advantaged social none in terms of wealth , power and prestige ( 22 ) .
additional considerations such as preventability or necessity have been proposed to judge whether a difference is inequitable , i.e. a difference could be considered inequitable if the factor is avoidable or it is not necessary ( 2 ) .
however even highly risky behavior such as sky diving could be avoided ; therefore the tragic outcome might not be inequitable ( 21 ) .
on the other hand there are viewpoints indicating that risk taking behaviors revolve around individuals free will , free choice and their own responsibility , which may not be supposed as unfair ; while these risk taking behaviors such as physical inactivity , smoking or addiction are consequences of social disparities and unequal opportunities enrooted in socio - economic determinants of health .
we have numerous examples of health inequalities in our experience ( urban heart ) , which could be assumed as unfair and consequently inequity .
health actions should be directed , at least in part , towards eliminating inequities in health .
whatever we take as theoretical basis , underlying principles or different wordings , all is about injustice ( 20 ) . to tackle the main controversies and challenges regarding the
disparities and health inequalities mainly affect socially disadvantaged none , who should be targeted in a balanced and sustainable urban planning . presenting the health and sdh inequalities ( as matrices ; see below ) to policy makers , practitioners , mayors , city governors , different sectors in the city , and the community , will make sufficient motive among all parties to reduce the inequalities .
measuring inequalities in health and its social determinants ( sdh ) is prerequisite for any master plan for healthy and sustainable cities .
urban health equity assessment and response tool ( urban heart ) was originally developed by the who kobe centre ( wkc : who centre for health development ) as a user - friendly guide for local and national officials to identify health inequities and plan actions to reduce them .
urban heart was pilot tested in tehran in 2008 and officials from 60 countries including 22 countries in eastern mediterranean region have been trained to employ this user - friendly guide so far .
urban heart seeks to give policy and decision makers at national and local levels , to :
identify the differences between the health , health determinants and well being of people living in disadvantaged urban areas and the general population ; and
determine appropriate , feasible , acceptable , and cost - effective strategies , interventions and actions which should be used to reduce inequity gaps between people living in the same city .
employing urban heart may have several bi - products for different parties such as determining a unique index to measure inequities for policy makers , identifying current gaps and relationship to other indices for public health practitioners , and empowering interested parties including community - based organizations , state or councils at localities , and ordinary dwellers .
urban heart is rather a strategic approach to define and track equity and health equity in urban settings .
equity , and a response component that encourage urban local governments to employ the best approaches to fill the existing gaps .
the former component assists the authorities in cities conduct a systematic assessment of unfair health conditions in the urban setting . to do this
, it stimulates users to think about the equity aspect of indicators .
for ease of analysis ,
the tool suggests reviewing evidence within four major policy domains including physical environment and infrastructure , social and human development ,
governance. these policy domains were extended to six in tehran model , where health and nutrition , and also
the health equity component also has a monitor ( for trend ) and a matrix ( to compare different locations ) that enable policy and decision makers to plot out health indicators ( e.g. percentage of households with access to safe water ) in such a way that a quick comparison can be made between the city and country ( and ultimately global or international standards ) and the extent of difference between disadvantaged city areas , the rest of the city and the country average , which provides sufficient evidence for decision making .
based on our previous experience in uh- 1 , the steering committee reviewed all available sources of information at international , national and local levels to determine health and socio - economic indicators and appropriate approaches for data collection .
uh-2 was mainly response - oriented , which indicates that all parts of equity assessment should be directed towards an action within the local community .
therefore a set of criteria was considered to select indicators : sdh - oriented , equity - oriented , internationally or nationally recognized , precise definition , comprehensiveness , and response - oriented .
the steering committee also considered the indispensable regulations by the city council , including adding cultural component to the main policy domains of urban heart .
table-1 demonstrates policy domains and indicators in both rounds of urban heart .
according to the documents reviewed in the working none and steering committee ,
some indicators were added , amended or discarded . among new indicators , there are green area , chronic diseases ( self - report ) , oral health , physical activity , pain , equal opportunity ( inter - generation equality ) , various home appliances ( dish washer and microwave ) , number of children books , and food insecurity .
amendments were conducted either in the definition of selected indicators or the way of measurement ; for example we changed the definition of access to toilet , so as to estimate the rate of standard sanitary toilets , or timely vaccination rate was targeted to avoid sophisticated observation and documentation of all vaccine types .
in addition , due to changes in health insurance funds , necessary modifications were made .
we also altered the way of administration for selected variables : our approach towards measuring body mass index ( bmi ) , access to public transport , and waste management were changed to self report .
finally a number of indicators such as access to tap water , and maternal mortality rate ( mmr ) were discarded .
according to the official boundaries in tehran , there are 374 neighborhoods across 22 districts , while six neighborhoods were non - residential or inaccessible due to security reasons , which were discarded from uh-2 study . to collect data in the remaining 368 neighborhoods of tehran , a multistage sampling was performed .
twenty two districts of the municipality and 368 neighborhoods were considered as stratum in the first stage and the second stage respectively .
using gis maps and a software to select random numbers , blocks were randomly identified to be included in the survey .
we required eight households in each block according to an eight - box table , which stands for four age none ( 15 - 24 , 25 - 44 , 45 - 64 , and 65 and over ) for both sex . employing a standard sample finding in population surveys , investigators started sample finding in each block by counting all houses first ( by counting rings and excluding business places , and vacant houses/ flats ) , and then the total house numbers were divided by eight to reach the ' gap number ' . following this , the investigator had to start the sample finding from the far right hand side using a random number , and then skipping the ' gap number ' so as to find the second house .
similar to the first round of the project , no substitution was permitted to ensure the randomization ( 16 ) .
sample size was then calculated based on cochrane formula
( z2a2p(1p)d2 )
as 1535 households in each district based on variables with at least 10% prevalence with a margin of error ( d ) of 0.015 and a confidence interval ( ci ) of 95% . then to facilitate the allocation of sample to the mentioned eight - box table that had to be completed for
the individual questionnaires and also to reach higher precision , the sample was expanded to 1600 households , regardless the population size in each district .
therefore , we assigned 200 blocks to each district equally . to allocate samples at neighborhood level , method of the probability proportional to size of each district
details of sampling frame and the structure of survey across 22 districts are presented in table.3 .
the total sample size was almost 34000 households for the first ( household ) questionnaire covering 118000 individuals from 368 neighborhoods , while a random sub - sample of 25000 cases were selected to reach a gender balanced sample across all districts . for the third questionnaire ( food frequency questionnaire ) , only one household within each block ( n= 4400 cases ) was selected conveniently to ensure their participation and responsiveness .
descriptive ( including central tendency , dispersion , percentile , cross - tabulation , and graphs ) and inferential ( such as t - test , correlation , regression models , principle component analysis , and non - parametric analysis ) statistics and inequality analysis were used for different variables .
in order to overcome insufficient sample size at neighborhood level , particularly in neighborhoods with less than 10 blocks ( i.e. less than 80 households ) , which account for 167 among the total 368 neighborhoods , and to provide reliable estimates of different variables , we used small area estimation , based on bayesian methods , which has been used extensively in recent years to solve small area estimation problems ( 23 ) .
this was initially tested to estimate the prevalence of low back pain in our study , which was highly reliable ( r=0.97 ) comparing with the real estimations at district level . due to the binary nature of chronic low back pain as response variable alongside available auxiliary data in unit - level
, a logistic mixed model and hierarchical bayes ( hb ) approach were used to estimate model parameters .
the first 14 parts were completed for all selected households in the blocks and the remaining six parts ( mental health , quality of life , social capital , body pain , physical activity and oral health ) were completed by selected individual in each household .
the last type of questionnaire , designed especially for food frequency , was completed for a selected household within each block .
in urban heart-2
we have collected data about demographics , assets , children health , accidents , domestic violence , disabilities , smoking and addiction , chronic diseases , household costs , nutrition habits , food insecurity , health service utilization and also individual data about mental health , health - related quality of life , pain , physical activity , social capital and oral health , through a multi - stage cluster random sampling proportional to population size at neighborhood level .
the whole process of data collection , local monitoring , data entry , and pooling were implemented by various parties in the municipality to build the capacity for further surveys , to minimize the costs and to ensure sustainability of measuring and responding to health inequalities .
five twoday workshop were organized to train 1240 surveyors ( auxiliary health workers based in the same neighborhoods ) and local supervisors to ensure that they know how to communicate with the families and encourage them to participate in survey , their capability to understand variable definitions , questionnaire instructions , sample finding , managing non - response cases , daily report and field supervision , and all details required for conducting the survey including security problems .
there was a multi - dimensional monitoring system including local supervision at neighborhood level , district monitoring by trained officers at district level , regular field visiting by trained officers at municipal level and telephone control by high rank members of steering committee .
general health questionnaires ( ghq-28 ) is a well known mental health tool , which was initially developed by goldberg and hillier ( 1979 ) for screening somatic symptoms , anxiety and insomnia , social dysfunction and severe depression .
a review of studies on the validation of the ghq28 in different countries , including iran , demonstrates its high validity and reliability as a screening tool of mental disorders in the community(25 ) .
the best cutoff point , determined using the conventional scoring method and the minimum overall misclassification rate , was 6 : that is , those scoring 6 and above were designated as possible cases of mental disorder .
sensitivity , specificity and overall misclassification rate for a ghq28 cut - off score of 6 were 84.7% , 93.8% and 8.2% , respectively(29 ) .
short form-12 ( sf-12 ) is a well known tool to measure health - related quality of life , which was also administered in the first round of urban heart in tehran .
( 26 ) sf-12 consists of 12 questions which leads to two major scores i.e. physical component score ( pcs ) and mental component score ( mcs ) .
social capital was assessed by a specific tool designed locally for the previous round of urban heart(27 ) .
the social capital tool covers two main dimensions -structural and cognitive- which measure six components of social capital i.e. collective activities , voluntary help , social cohesion and inclusion , social network , reciprocity and trust .
a simple pain questionnaire which deals with the incidence and prevalence of either acute or chronic pain ( longer than three months ) in different sites such as back pain , neck , shoulder , limbs , knee pain , headache and toothache , was completed by the same selected individual .
the last question for all types of pain asked about seeking medical advice . in total , 24874 individuals ( 52.5% female ) completed pain questionnaire .
we added a specific section for oral health , consisting of utilization of dental service , oral health behaviors ( using toothbrush and toothpaste ) , oral quality of life , and observing tooth loss or decay .
more than 24400 over 15 year s old adults responded to the oral health questionnaire .
the last part of individual section was global physical activity questionnaire ( gpaq ) as a who - approved standard tool , which had been validated in several crossnational ( 28 ) and national studies ( 30 ) , was self - administrated to a selected person within each household .
there are 3 main domains in the pa tool , which measures physical activity at work , commuting and recreation .
data on the prevalence of physical activity were completely collected for 17153 adults over 15 years old across 22 districts of tehran .
according to the
there are almost ten local structures within neighborhood halls including health house where at least two auxiliary health workers partially paid by the municipality- provide social health and counseling in all 374 neighborhoods .
there are six working none endorsed by the city council , consisting of volunteer local experts , local authorities and ngos in each 374 neighborhoods of tehran .
these local working none cover social , educational and empowerment , health and environment ,
culture , emergency , safety and resilience , sport and recreation , and service provision and welfare.
our main focus in uh-2 was on knowledge transfer to all neighborhoods councils and other local structures to raise their awareness about sdh status at their localities so as to prioritize their health ( and sdh ) problems and implement appropriate activities to reduce inequalities . in order to facilitate participation of local residents ,
an integrated local committee was established to select up to three health and sdh priorities within the neighborhood and develop appropriate action plan to reduce inequalities in a given time ; see below for more details .
these plans of action are being monitored within district and being evaluated by third parties across tehran .
based on our previous experience in uh- 1 , the steering committee reviewed all available sources of information at international , national and local levels to determine health and socio - economic indicators and appropriate approaches for data collection .
uh-2 was mainly response - oriented , which indicates that all parts of equity assessment should be directed towards an action within the local community .
therefore a set of criteria was considered to select indicators : sdh - oriented , equity - oriented , internationally or nationally recognized , precise definition , comprehensiveness , and response - oriented .
the steering committee also considered the indispensable regulations by the city council , including adding cultural component to the main policy domains of urban heart .
table-1 demonstrates policy domains and indicators in both rounds of urban heart .
according to the documents reviewed in the working none and steering committee ,
some indicators were added , amended or discarded . among new indicators , there are green area , chronic diseases ( self - report ) , oral health , physical activity , pain , equal opportunity ( inter - generation equality ) , various home appliances ( dish washer and microwave ) , number of children books , and food insecurity .
amendments were conducted either in the definition of selected indicators or the way of measurement ; for example we changed the definition of access to toilet , so as to estimate the rate of standard sanitary toilets , or timely vaccination rate was targeted to avoid sophisticated observation and documentation of all vaccine types .
in addition , due to changes in health insurance funds , necessary modifications were made .
we also altered the way of administration for selected variables : our approach towards measuring body mass index ( bmi ) , access to public transport , and waste management were changed to self report .
finally a number of indicators such as access to tap water , and maternal mortality rate ( mmr ) were discarded .
according to the official boundaries in tehran , there are 374 neighborhoods across 22 districts , while six neighborhoods were non - residential or inaccessible due to security reasons , which were discarded from uh-2 study . to collect data in the remaining 368 neighborhoods of tehran
twenty two districts of the municipality and 368 neighborhoods were considered as stratum in the first stage and the second stage respectively .
using gis maps and a software to select random numbers , blocks were randomly identified to be included in the survey .
we required eight households in each block according to an eight - box table , which stands for four age none ( 15 - 24 , 25 - 44 , 45 - 64 , and 65 and over ) for both sex . employing a standard sample finding in population surveys , investigators started sample finding in each block by counting all houses first ( by counting rings and excluding business places , and vacant houses/ flats ) , and then the total house numbers were divided by eight to reach the ' gap number ' . following this , the investigator had to start the sample finding from the far right hand side using a random number , and then skipping the ' gap number ' so as to find the second house .
similar to the first round of the project , no substitution was permitted to ensure the randomization ( 16 ) .
sample size was then calculated based on cochrane formula
( z2a2p(1p)d2 )
as 1535 households in each district based on variables with at least 10% prevalence with a margin of error ( d ) of 0.015 and a confidence interval ( ci ) of 95% . then to facilitate the allocation of sample to the mentioned eight - box table that had to be completed for
the individual questionnaires and also to reach higher precision , the sample was expanded to 1600 households , regardless the population size in each district .
therefore , we assigned 200 blocks to each district equally . to allocate samples at neighborhood level , method of the probability proportional to size of each district
details of sampling frame and the structure of survey across 22 districts are presented in table.3 .
the total sample size was almost 34000 households for the first ( household ) questionnaire covering 118000 individuals from 368 neighborhoods , while a random sub - sample of 25000 cases were selected to reach a gender balanced sample across all districts . for the third questionnaire ( food frequency questionnaire ) , only one household within each block ( n= 4400 cases ) was selected conveniently to ensure their participation and responsiveness .
descriptive ( including central tendency , dispersion , percentile , cross - tabulation , and graphs ) and inferential ( such as t - test , correlation , regression models , principle component analysis , and non - parametric analysis ) statistics and inequality analysis were used for different variables .
in order to overcome insufficient sample size at neighborhood level , particularly in neighborhoods with less than 10 blocks ( i.e. less than 80 households ) , which account for 167 among the total 368 neighborhoods , and to provide reliable estimates of different variables , we used small area estimation , based on bayesian methods , which has been used extensively in recent years to solve small area estimation problems ( 23 ) .
this was initially tested to estimate the prevalence of low back pain in our study , which was highly reliable ( r=0.97 ) comparing with the real estimations at district level . due to the binary nature of chronic low back pain as response variable alongside available auxiliary data in unit - level
, a logistic mixed model and hierarchical bayes ( hb ) approach were used to estimate model parameters .
the first 14 parts were completed for all selected households in the blocks and the remaining six parts ( mental health , quality of life , social capital , body pain , physical activity and oral health ) were completed by selected individual in each household . the last type of questionnaire , designed especially for food frequency , was completed for a selected household within each block .
in urban heart-2
we have collected data about demographics , assets , children health , accidents , domestic violence , disabilities , smoking and addiction , chronic diseases , household costs , nutrition habits , food insecurity , health service utilization and also individual data about mental health , health - related quality of life , pain , physical activity , social capital and oral health , through a multi - stage cluster random sampling proportional to population size at neighborhood level .
the whole process of data collection , local monitoring , data entry , and pooling were implemented by various parties in the municipality to build the capacity for further surveys , to minimize the costs and to ensure sustainability of measuring and responding to health inequalities .
five twoday workshop were organized to train 1240 surveyors ( auxiliary health workers based in the same neighborhoods ) and local supervisors to ensure that they know how to communicate with the families and encourage them to participate in survey , their capability to understand variable definitions , questionnaire instructions , sample finding , managing non - response cases , daily report and field supervision , and all details required for conducting the survey including security problems .
there was a multi - dimensional monitoring system including local supervision at neighborhood level , district monitoring by trained officers at district level , regular field visiting by trained officers at municipal level and telephone control by high rank members of steering committee .
general health questionnaires ( ghq-28 ) is a well known mental health tool , which was initially developed by goldberg and hillier ( 1979 ) for screening somatic symptoms , anxiety and insomnia , social dysfunction and severe depression .
a review of studies on the validation of the ghq28 in different countries , including iran , demonstrates its high validity and reliability as a screening tool of mental disorders in the community(25 ) .
the best cutoff point , determined using the conventional scoring method and the minimum overall misclassification rate , was 6 : that is , those scoring 6 and above were designated as possible cases of mental disorder .
sensitivity , specificity and overall misclassification rate for a ghq28 cut - off score of 6 were 84.7% , 93.8% and 8.2% , respectively(29 ) .
short form-12 ( sf-12 ) is a well known tool to measure health - related quality of life , which was also administered in the first round of urban heart in tehran .
( 26 ) sf-12 consists of 12 questions which leads to two major scores i.e. physical component score ( pcs ) and mental component score ( mcs ) .
social capital was assessed by a specific tool designed locally for the previous round of urban heart(27 ) .
the social capital tool covers two main dimensions -structural and cognitive- which measure six components of social capital i.e. collective activities , voluntary help , social cohesion and inclusion , social network , reciprocity and trust .
a simple pain questionnaire which deals with the incidence and prevalence of either acute or chronic pain ( longer than three months ) in different sites such as back pain , neck , shoulder , limbs , knee pain , headache and toothache , was completed by the same selected individual . the last question for all types of pain asked about seeking medical advice . in total , 24874 individuals ( 52.5% female ) completed pain questionnaire
. we added a specific section for oral health , consisting of utilization of dental service , oral health behaviors ( using toothbrush and toothpaste ) , oral quality of life , and observing tooth loss or decay .
more than 24400 over 15 year s old adults responded to the oral health questionnaire .
the last part of individual section was global physical activity questionnaire ( gpaq ) as a who - approved standard tool , which had been validated in several crossnational ( 28 ) and national studies ( 30 ) , was self - administrated to a selected person within each household .
there are 3 main domains in the pa tool , which measures physical activity at work , commuting and recreation .
data on the prevalence of physical activity were completely collected for 17153 adults over 15 years old across 22 districts of tehran .
there are almost ten local structures within neighborhood halls including health house where at least two auxiliary health workers partially paid by the municipality- provide social health and counseling in all 374 neighborhoods .
there are six working none endorsed by the city council , consisting of volunteer local experts , local authorities and ngos in each 374 neighborhoods of tehran .
these local working none cover social , educational and empowerment , health and environment ,
culture , emergency , safety and resilience , sport and recreation , and service provision and welfare.
our main focus in uh-2 was on knowledge transfer to all neighborhoods councils and other local structures to raise their awareness about sdh status at their localities so as to prioritize their health ( and sdh ) problems and implement appropriate activities to reduce inequalities . in order to facilitate participation of local residents ,
an integrated local committee was established to select up to three health and sdh priorities within the neighborhood and develop appropriate action plan to reduce inequalities in a given time ; see below for more details .
these plans of action are being monitored within district and being evaluated by third parties across tehran .
health inequities are embedded in societal inequities , which deprive subgroups of the population to benefit from social and economic development ( 18 ) .
therefore we focused on different aspects of socio economic determinants of health to explore disparities , which eventually affect the health of urban residents at neighborhood level . in the second round of project ( 2011 ) we revised the indicators thoroughly to cover more social factors and more health outcomes .
in addition , findings were disaggregated by all neighborhoods , either with direct estimation or using statistical models to report inequalities to all
the second round of urban heart had three major differences from the previous round :
we collected sdh data disaggregated by all 374 neighborhoods of tehran ,
secondly , the social health workers affiliated to the municipality were involved in the project , responsible for data collection and implementing appropriate interventions ;
more importantly , the focus of second round of urban heart project in tehran was on
response part , which targets community - based interventions to tackle disparities .
during 2012
we explained the importance of findings and the role of all 22 district municipalities and relevant local authorities ( including district mayors deputies , zone mayors , neighborhood managers and neighborhood councils ) to encourage them implementing the
a briefing meeting was held in each 22 districts to present local data , highlight disparities in neighborhoods , triangulate uh data with local data , discussing over interested issues and explain the methods for community - based and intersectoral implementation .
local councils were then envisaged to :
prioritize local problems according to the findings of assessment section , prepare community based programs to meet the local needs ,
organize the community for advocating physical activities in daily schedule of the people ,
establish the intersectoral coordination at local level through neighborhood development committee ( ndc ) ,
promote the accountability of local councils , and
develop transparent planning and resource allocation within neighborhoods .
* more blocks and households in districts 18 and 20were recruited to cover slum areas in both districts .
*
also there are two non - residential neighborhoods in this district which convinced the steering committee to diminish the sample size , which ended in 142 blocks ( 1131 households ) .
neighborhood development committee which constitutes local key members and influential individuals were established in all 368 neighborhoods , where the assessment part was conducted , chaired by the neighborhood manager .
these key people are including , but not limited to neighborhood manager , representatives of six neighborhood working none , director of neighborhood health house , neighborhood social worker , and 1 - 2 local expert/ scholar selected by the neighborhood council.
ndc is expected to fulfill the following roles :
choosing transferable data to local people ;
identifying the method of knowledge transfer ( local media , face - to - face meetings , etc . ) ;
collecting local people viewpoints ( as a source of data triangulation ) ;
setting up to five social determinants of health priorities to be presented in the neighborhood council ;
discussing evidence - based solutions ( plan of action ) which are developed by the relevant working none for the selected and approved sdh priority .
the main policy in the second round of urban heart and beyond is to institutionalize the whole process within routine responsibilities and tasks of the municipality of tehran , therefore all organizations , departments and district municipalities were involved in different parts of urban heart - phase 2 .
main funding bodies for implementing urban heart - phase 2 were as following :
funds from deputy for social and cultural affairs , municipality of tehran , which was mainly spent for data collection
neighborhood councils funds with limited contributions to host intersectoral team meetings , setting priorities , and develop a local action plan to respond the inequalities ; for this particular pa experiences : to promote physical activity within the local community
funds by districts municipalities to support the action plans run in different neighborhoods across the district .
these funds support intersectoral activities which are mainly implemented in public places such as parks , streets , and local sport areas ( all covered by municipality ) and local schools ( either state or private ) .
voluntary and free of charge services by the auxiliary health workers .
by completion of the first round of urban heart ( 16 )
52 sdh related indicators in the same policy domains , were endorsed by the cabinet to monitor heath and social determinants across all 400 districts of the country .
more than 40 indicators were routinely collected through health and other relevant sectors at national level during 2012 and the remaining 10 indicators such as mental health , healthcare utilization , the prevalence of osteoporosis , body mass index , physical activity , smoking and addiction , and health economic indicators are going to be collected through a national survey disaggregated by all districts in 2013 .
as a response to global call to action by who ( 31 ) the regional office of eastern mediterranean organized an inter - country workshop in september 2012 consisting of all 22 countries across the region , where uh-2 findings were reviewed to enhance utilization of urban heart in at least one city of all regional member states by 2014 ( 32 ) .
despite comprehensiveness of urban heart-2 as a model for measuring inequalities in social determinants of health
first of all time limitation to avoid coincidence with national census , compelled the core investigators to conduct the whole process of data collection in 25 days across twenty two districts of tehran , which led to enormous pressure on field investigators ( auxiliary health workers ) , which in turn made some of them ( 12% ) detaching from data collection process . to substitute detached filed investigators we had to train more eligible persons or to reposition surveyors , which might affect the quality of data collection .
secondly , eight neighborhoods ( out of 374 ) were removed from data collection , due to non - residential and/or military based blocks , where basic data were obtained either through other routine sources or data modeling .
third , detailed questions usually make respondents refrain from completing the questionnaire(s ) ; our investigators also encountered this limitation , however local solutions such as minor rewarding were used to encourage responding , which led to high response rate in most districts .
fourth , questioning process was occurred mostly in day time , which led to a female dominant ( > 60% ) response for individual questionnaires . to overcome gender bios ,
a random sample was selected , which diminished our total sample size for individual sections to over 25000 cases .
last but not the least , it is highly recommended to build a cohort design either household or
we did not follow the same households or blocks due to technical and logistic limitations , however employing local health auxiliaries will allow the investigators to make better records so that they will have access to local participants in the next rounds of the project .
this study protocol demonstrated rationale , concepts , methodological framework , challenges and implications of urban heart-2 project in tehran . following the first round of urban heart project in 2008 ,
the second round was conducted in november 2011 , to track changes over time , to institutionalize inequality assessment within the local government , to build up community participation in assessment and response parts of the project , and to implement appropriate and evidence - based actions to reduce health inequalities within all neighborhoods of tehran .
results of more than 60 indicators have been disaggregated by 368 neighborhoods of tehran and endorsed by the mayor to all local authorities so that appropriate action plans being developed and implemented to tackle inequalities .
equity point of view , and also to monitor and scrutinize widespread local action plans , which are currently undertaking within all neighborhoods .
during 2012 we explained the importance of findings and the role of all 22 district municipalities and relevant local authorities ( including district mayors deputies , zone mayors , neighborhood managers and neighborhood councils ) to encourage them implementing the
a briefing meeting was held in each 22 districts to present local data , highlight disparities in neighborhoods , triangulate uh data with local data , discussing over interested issues and explain the methods for community - based and intersectoral implementation .
local councils were then envisaged to :
prioritize local problems according to the findings of assessment section , prepare community based programs to meet the local needs ,
organize the community for advocating physical activities in daily schedule of the people ,
establish the intersectoral coordination at local level through neighborhood development committee ( ndc ) ,
promote the accountability of local councils , and
develop transparent planning and resource allocation within neighborhoods .
* more blocks and households in districts 18 and 20were recruited to cover slum areas in both districts .
*
also there are two non - residential neighborhoods in this district which convinced the steering committee to diminish the sample size , which ended in 142 blocks ( 1131 households ) .
neighborhood development committee which constitutes local key members and influential individuals were established in all 368 neighborhoods , where the assessment part was conducted , chaired by the neighborhood manager .
these key people are including , but not limited to neighborhood manager , representatives of six neighborhood working none , director of neighborhood health house , neighborhood social worker , and 1 - 2 local expert/ scholar selected by the neighborhood council.
ndc is expected to fulfill the following roles :
choosing
transferable data to local people ;
identifying the method of knowledge transfer ( local media , face - to - face meetings , etc . ) ;
collecting local people viewpoints ( as a source of data triangulation ) ;
setting up to five social determinants of health priorities to be presented in the neighborhood council ;
discussing evidence - based solutions ( plan of action ) which are developed by the relevant working none for the selected and approved sdh priority .
the main policy in the second round of urban heart and beyond is to institutionalize the whole process within routine responsibilities and tasks of the municipality of tehran , therefore all organizations , departments and district municipalities were involved in different parts of urban heart - phase 2 .
main funding bodies for implementing urban heart - phase 2 were as following :
funds from deputy for social and cultural affairs , municipality of tehran , which was mainly spent for data collection
neighborhood councils funds with limited contributions to host intersectoral team meetings , setting priorities , and develop a local action plan to respond the inequalities ; for this particular pa experiences : to promote physical activity within the local community
funds by
these funds support intersectoral activities which are mainly implemented in public places such as parks , streets , and local sport areas ( all covered by municipality ) and local schools ( either state or private ) .
by completion of the first round of urban heart ( 16 ) 52 sdh related indicators in the same policy domains , were endorsed by the cabinet to monitor heath and social determinants across all 400 districts of the country .
more than 40 indicators were routinely collected through health and other relevant sectors at national level during 2012 and the remaining 10 indicators such as mental health , healthcare utilization , the prevalence of osteoporosis , body mass index , physical activity , smoking and addiction , and health economic indicators are going to be collected through a national survey disaggregated by all districts in 2013 .
as a response to global call to action by who ( 31 ) the regional office of eastern mediterranean organized an inter - country workshop in september 2012 consisting of all 22 countries across the region , where uh-2 findings were reviewed to enhance utilization of urban heart in at least one city of all regional member states by 2014 ( 32 ) .
despite comprehensiveness of urban heart-2 as a model for measuring inequalities in social determinants of health
first of all time limitation to avoid coincidence with national census , compelled the core investigators to conduct the whole process of data collection in 25 days across twenty two districts of tehran , which led to enormous pressure on field investigators ( auxiliary health workers ) , which in turn made some of them ( 12% ) detaching from data collection process . to substitute detached filed investigators we had to train more eligible persons or to reposition surveyors , which might affect the quality of data collection .
secondly , eight neighborhoods ( out of 374 ) were removed from data collection , due to non - residential and/or military based blocks , where basic data were obtained either through other routine sources or data modeling .
third , detailed questions usually make respondents refrain from completing the questionnaire(s ) ; our investigators also encountered this limitation , however local solutions such as minor rewarding were used to encourage responding , which led to high response rate in most districts .
fourth , questioning process was occurred mostly in day time , which led to a female dominant ( > 60% ) response for individual questionnaires . to overcome gender bios ,
a random sample was selected , which diminished our total sample size for individual sections to over 25000 cases .
last but not the least , it is highly recommended to build a cohort design either household or
we did not follow the same households or blocks due to technical and logistic limitations , however employing local health auxiliaries will allow the investigators to make better records so that they will have access to local participants in the next rounds of the project .
this study protocol demonstrated rationale , concepts , methodological framework , challenges and implications of urban heart-2 project in tehran .
following the first round of urban heart project in 2008 , the second round was conducted in november 2011 , to track changes over time , to institutionalize inequality assessment within the local government , to build up community participation in assessment and response parts of the project , and to implement appropriate and evidence - based actions to reduce health inequalities within all neighborhoods of tehran .
results of more than 60 indicators have been disaggregated by 368 neighborhoods of tehran and endorsed by the mayor to all local authorities so that appropriate action plans being developed and implemented to tackle inequalities .
equity point of view , and also to monitor and scrutinize widespread local action plans , which are currently undertaking within all neighborhoods . | background
current evidence consistently confirm inequalities in health status among socioeconomic none , gender , ethnicity , geographical area and other social determinants of health ( sdh ) , which adversely influence health ofthe population .
sdh refer to a wide range of factors not limited to social component , but also involve economic , cultural , educational , political or environmental problems . measuring inequalities , improving daily living conditions , andtackling inequitable distribution of resources
are highly recommended by international sdh commissioners in recentyears to close the gaps within a generation. to measure inequalities in socio - economic determinants and core healthindicators in tehran , the second round of urban health equity assessment and response tool ( urban heart-2)was conducted in november 2011 , within the main framework of who centre for health development ( kobe centre ) .
methodfor
assessment part of the project , 65 indicators in six policy domains namely physical and infrastructure,human and social ,
economic ,
governance , health and nutrition , and also cultural domain were targetedeither through a population based survey or using routine system .
survey was conducted in a multistage random sampling , disaggregated to 22 districts and 368 neighborhoods of tehran , where data of almost 35000 households(118000 individuals ) were collected . for
response part of the project , widespread community based development(cbd ) projects were organized in all 368 neighborhoods , which are being undertaken throughout 2013.conclusionfollowing the first round of urban heart project in 2008 , the second round was conducted to trackchanges over time , to institutionalize inequality assessment within the local government , to build up community participationin assessment and response parts of the project , and to implement appropriate and evidence - based actionsto reduce health inequalities within all neighborhoods of tehran . |
as a minimally invasive technique , laparoscopic surgery is widely used in benign gynecologic diseases and may also be used in malignancies such as endometrial cancer , cervical cancer , and early ovarian cancer .
recent studies have demonstrated that laparoscopic surgical staging of early ovarian cancer is as safe and adequate as open laparotomy .
technologic advances in endoscopic instrumentation and optics have allowed the development of a less invasive alternative to conventional laparoscopy ; single - port access ( spa ) laparoscopic surgery . by using a single multichannel port access system ,
spa laparoscopy is an attempt to further enhance the cosmetic benefits of minimally invasive surgery while minimizing the potential risks and morbidity associated with multiple working ports .
in addition , it was proved that spa laparoscopic adnexal surgery had comparable operative outcomes to conventional laparoscopic adnexal surgery . in gynecologic malignancy , there is one case series that included two patients who had received lymph node dissection during the staging operation .
the number of harvested lymph node in the two patients was only 11 and 13 , respectively .
here we report a case of borderline ovarian tumor treated with spa laparoscopic staging operation .
a 34-year - old woman , gravida 2 , para 2 , visited our clinic with an incidentally found right ovarian cyst . on pelvic examination
transvaginal ultrasonography revealed a 4.03.8 cm sized mixed - echogenic right ovarian cyst ( fig .
1 ) . the results of laboratory studies , including analysis of tumor markers , such as ca125 , ca19 - 9 , were all within normal limits ( ca125 , 5.9 ; ca19 - 9 , 30.2 u / ml ) . she had received two cesarean sections with a transverse incision , and had no plans for further children .
her height was 160.1 cm and weight was 60.3 kg with a body mass index of 23.53 kg / m .
as the result of intraoperative frozen biopsy of right ovary was a borderline tumor , we decided to change the method of surgery to a staging laparoscopy .
the total operative time was 280 minutes , and the estimated blood loss was 300 ml . on gross examination ,
the right ovary was enlarged and had a smooth cyst about 4 cm in size , but no other abnormalities were identified .
pathological examination showed a mucinous borderline tumor of the right ovary and patient 's surgical stage was diagnosed as ia .
initial hemoglobin level was 14.3 g / dl , and follow - up level was 13.2 g / dl on the postoperative day 1 .
visual analogue scores for pain at 4 hours and 24 hours after surgery were 6/10 and 4/10 retrospectively .
she was discharged on the postoperative day 7 after the final pathologic result was confirmed .
the surgeon stood on the left side of the patient , and the first assistant stood on the right side of the patient to handle the scope .
the second assistant was positioned between the legs of the patient , manipulating the uterine elevator .
the patient 's left arm was tied to her body for the surgeon 's space .
a 2-cm vertical intra - umbilical skin incision was performed via an open hasson approach .
the alexis wound retractor ( applied medical , rancho santa margarita , ca , usa ) was inserted through the incision .
then a sterile surgical glove with sheaths inserted into 3 fingers was draped around the rim of the wound retractor .
we used a rigid 45-degree , 5-mm laparoscope ( ideal eyes 5 mm 45 deg , stryker , san jose , ca , usa ) and 5-mm flexible laparoscope instruments ( e.g. , roticulator , covidien , mansfield , ma ; cambridge endoscopic devices , framingham , ma , usa ) .
, we used a harmonic scalpel ( harmonic ace , ethicon endo - surgery inc . ,
bilateral pelvic lymph node dissection , infracolic omentectomy , and appendectomy were performed using a harmonic scalpel on the right hand and a roticular dissector on the left hand ( fig .
the omentum , appendix , uterus , and left salpinx and ovary were removed through the vagina .
another opening was made on the suprapubic area to place a jackson - pratt drain in the pelvic cavity .
the trocar was introduced into the pelvic cavity through the suprapubic skin and extracted via the umbilical incision site manipulating with a grasper ( fig .
4 ) . the peritoneum and fascia of the umbilical opening were approximated and closed layer by layer with 2 - 0 polysorp ( covidien syneture , norwalk , ct , usa ) suture . for skin closure
, we used dermabond ( ethicon inc , somerville , nj , usa ) , which provided a good cosmetic outcome and did not require later stitching out .
the surgeon stood on the left side of the patient , and the first assistant stood on the right side of the patient to handle the scope .
the second assistant was positioned between the legs of the patient , manipulating the uterine elevator .
the patient 's left arm was tied to her body for the surgeon 's space .
a 2-cm vertical intra - umbilical skin incision was performed via an open hasson approach .
the alexis wound retractor ( applied medical , rancho santa margarita , ca , usa ) was inserted through the incision .
then a sterile surgical glove with sheaths inserted into 3 fingers was draped around the rim of the wound retractor .
we used a rigid 45-degree , 5-mm laparoscope ( ideal eyes 5 mm 45 deg , stryker , san jose , ca , usa ) and 5-mm flexible laparoscope instruments ( e.g. , roticulator , covidien , mansfield , ma ; cambridge endoscopic devices , framingham , ma , usa ) .
, we used a harmonic scalpel ( harmonic ace , ethicon endo - surgery inc . ,
2 ) . bilateral pelvic lymph node dissection , infracolic omentectomy , and appendectomy were performed using a harmonic scalpel on the right hand and a roticular dissector on the left hand ( fig .
the omentum , appendix , uterus , and left salpinx and ovary were removed through the vagina .
another opening was made on the suprapubic area to place a jackson - pratt drain in the pelvic cavity .
the trocar was introduced into the pelvic cavity through the suprapubic skin and extracted via the umbilical incision site manipulating with a grasper ( fig .
4 ) . the peritoneum and fascia of the umbilical opening were approximated and closed layer by layer with 2 - 0 polysorp ( covidien syneture , norwalk , ct , usa ) suture . for skin closure
, we used dermabond ( ethicon inc , somerville , nj , usa ) , which provided a good cosmetic outcome and did not require later stitching out .
the major principle of minimally invasive surgery is to be less invasive , leading to less physiologic stress , faster recovery , and better cosmetic results . from a technical standpoint ,
spa laparoscopy in the field of minimally invasive surgery is the most recently emerging and promising method . in 1994 ,
querleu and leblanc first demonstrated that laparoscopic surgery may be used to adequately stage ovarian malignancies . since then , several investigators reported some cases of laparoscopic surgical staging of early ovarian cancer ( eoc ) .
described that laparoscopic surgical staging of eoc is as safe and adequate as the standard surgical staging performed via laparotomy , and offers a shorter hospital stay . in 2009
fader and escobar first demonstrated in a series of patients referred for staging that spa laparoscopic surgery may be used to adequately stage ovarian malignancies .
the study of two port access staging laparoscopy was reported recently as a feasible procedure in selected gynecologic cancer patients . in accordance with a previous study , we demonstrated that staging operation of early ovarian cancer may be performed using spa laparoscopy .
furthermore , the number of lymph nodes in this case is sufficient compared to the results of other studies .
consequently , spa laparoscopic staging of early ovarian cancer may be accomplished successfully with pelvic lymph node dissection , for patients whose disease appear to be limited to the adnexa
first , paraaortic lymph node dissection was not done due to technical difficulty and a high risk of complications .
second , at the end of the operation , another 3 mm puncture on the suprapubic area was needed to insert the drain tube .
recent meta - analysis reveals that placement of retroperitoneal tube drains has no benefit in the prevention of lymphocyst formation after pelvic lymphadenectomy in patients with gynecological malignancies .
based on this analysis , the drainage system may be omitted in future cases . in conclusion , staging operation using spa laparoscopy was successfully done , and it may be a feasible procedure in selected gynecologic cancer patients who have early - staged ovarian or endometrial cancer , and who are concerned for postoperative scarring .
the efficacy , safety , and potential benefits of this technique in cancer staging operation should be evaluated in further trials . | minimally invasive surgery is widely used in benign gynecologic diseases and may be used in malignancies .
we performed a single - port access laparoscopy staging - bilateral salpingo - oophorectomy , laparoscopy - assisted vaginal hysterectomy , bilateral pelvic lymphadenectomy , infracolic omentectomy , and washing cytology - in a borderline ovarian tumor .
the number of harvested pelvic lymph nodes were twenty - three and there were no intraoperative or postoperative complications .
single - port access laparoscopic staging may be performed in selected patients .
the efficacy , safety , and potential benefits of this technique should be evaluated in further trials . |
a 34-year - old female with end - stage renal disease treated by peritoneal dialysis ( pd ) complained of dry cough that had started 1 month previously .
the patient 's medications consisted of a calcium channel blocker , angiotensin receptor blocker , erythropoietin , ferrous sulfate , and sevelamer .
a chest x - ray showed a pleural effusion on the right side ( fig .
a thoracic drainage was placed into the pleural effusion and 1 l of clear liquid was emptied .
samples were sent to the chemistry laboratory , to microbiology , and to pathology for further studies .
the following results were obtained : glucose , 278 mg / dl ( plasma glucose , 115 mg / dl ) ; total protein < 1.0 g / dl ( total protein in plasma , 7.9 g / dl ) ; lactate dehydrogenase , 49 u / l ( ldh in plasma , 459 u / l ) ; ada , 2.7 iu / l ( 4.3 - 20.3 ) . the effusion contained no malignant cells and the culture grew out no microorganisms .
we performed chest computed tomography 1 hour after injecting radiocontrast medium intraperitoneally mixed with 4.25% pd solution .
the scan showed focal penetration of intra - abdominal contrast medium via the right hemidiaphragm in the right posterior and lower hemithorax , suggesting a small peritoneopleural fistula ( fig .
2 ) . pleural effusions and hydrothorax are rare complications in pd patients and result from the migration of dialysis fluid under pressure from the peritoneal cavity into the pleural space.1,2 increased intra - abdominal pressure arises either transiently with coughing or straining or permanently from a large volume of pd solution .
the mechanism by which peritoneal dialysate transverses the diaphragm is thought to be due to a pleuroperitoneal communication .
a sudden increase in intra - abdominal pressure opens a communication between the abdomen and the thorax , allowing pd fluid to leak into the thorax.3 hydrothorax frequently presents as respiratory distress , particularly dyspnea or shortness of breath .
a high glucose level in the pleural effusion is an important clue because no other form of hydrothorax has elevated glucose levels.4 pd solution in the thoracic cavity presents a unique situation that occurs only in patients receiving pd .
as described in the literature , in most cases , the peritoneopleural fistula is diagnosed by use of scintigraphy
. however , scintigraphy is not able to localize a defect in the diaphragm . in the present case ,
mri has also been attempted to show transdiaphragmatic leakage in a peritoneoflural fistula.5 different therapeutic approaches have been reported .
temporary discontinuation of pd , tetracycline instillation into the pleural space , and surgical patch grafting of the diaphragmatic leak have all been described .
a novel method may be video - assisted talc pleurodesis.6 this patient received hemodialysis via a permanent catheter after quitting pd . | a 34-year - old female presented with end - stage renal disease ( esrd ) treated by peritoneal dialysis ( capd ) complained of a dry cough .
chest x - ray and chest computed tomography ( ct ) scan revealed massive right hydrothorax . because the glucose concentration of pleural fluid was markedly high compared with that of serum , we performed isotope and contrast peritoneography .
we used ct for localizing it .
mri was also trying to show transdiaphragmatic leakage in peritoneoflural fistula .
temporary discontinuation of capd , tetracycline instillation into the pleural space and surgical patch grafting of the diaphragmatic leak have all been described .
a novel method may be video - assisted talc pleurodesis . |
firefighters and aid workers are considered to be victims of heat stress in physiological activities . moving and lifting heavy objects or saving people under stressful conditions
are such activates done by firefighters while wearing protective clothes and a compressed air breathing apparatus .
numerous studies indicated that individuals appropriate physical performance depends on vo2-max , which is defined as the maximum amount of oxygen that can be absorbed by the respiratory system and be sent to operating muscles .
previous studies showed that vo2-max ranged from 33.5 to 45 ml / kg body weight per minute among firefighters .
's study conducted in belgium , the rate of vo2-max was estimated to be 46.5 ml / kg body weight per minute among firefighters . moreover , pulmonary function test or spirometry is identified as another method to assess cardiorespiratory system 's health .
spirometry is the most common pulmonary function test , giving the rate , volume , speed , or flow of an individual 's inhalation and exhalation .
the test consists of three main parameters , namely , forced expiratory volume in 1 s ( fev1 ) , forced vital capacity ( fvc ) , and fev1/fvc .
fvc refers to the amount of air an individual exhales from one 's lung after a deep inhalation .
fev1 is also defined as the amount of air an individual forcefully exhales from one 's lung in the first second of exhalation .
finally , fev1/fvc is the ratio of the second to the first parameter and indicates the percentage of fvc exhaled from lung in the first second of exhalation . in comparison with the society , firefighters have better pulmonary function , particularly in fvc and fev1 parameters .
however , due to the increase in utilization of chemical materials in buildings in the recent decades , concerns have risen about this group 's health . regarding the results of some studies , exposure to smoke and fumes including acrolein ,
carbon monoxide , hydrogen chloride , hydrogen cyanide , nitrogen oxides , sulfur dioxide , particles , aldehydes , and carcinogens led to chronic pulmonary damages followed by reduction of pulmonary function .
numerous studies revealed the acute effects of exposure to smoke on firefighters health , particularly pulmonary function .
for instance , according to a study conducted on 28 firefighters , a considerable obstructive pulmonary disease within few hours after exposure to smoke was found .
in addition , the findings of musk et al . revealed that occurs a significant reduction in fev1 among smoker peoples .
considering what was mentioned above and firefighters heavy physical requirements , it is essential to assess their cardiorespiratory function accurately .
hence , this study aimed to investigate respiratory complications and assess of vo2-max , lung volumes , and their associated factors among firefighters in one of the central cities of fars province , iran .
this is a cross - sectional study on firefighters who were participating in fire suppression and rescue operations in one of the central cities of fars province , iran . using a systematic random sampling approach and based on a priori sample size calculation ,
110 firefighters were selected from various stations among which 104 participants agreed to participate in all the stages of the research . all participants with at least 1 year of working experience were interviewed and those with any history of cardiovascular or respiratory disorders and smoking were excluded from the study .
an self - administered questionnaire was used to collect information on the participant 's demographic and respiratorystatus . this questionnaire used in several studies and
pulmonary function tests were measured based on ats guidelines using a spirometer ( vitalograph compact ii , england ) .
three acceptable spirometry maneuvers , therefore , were obtained from each participant and the best one was recorded .
vo2-max was evaluated using the protocol developed by tuxworth - shahnavaz on an iranian society in 1977 . in this protocol , individuals go up and down step ( height : 40 cm ) with a cadence of 25 times in a minute for 5 min .
then , they sit on a chair , their heart rate is measured in three 30 s stages ( m1 : 3060 s , m2 : 90120 s , and m3 : 150180 s [ figure 1 ] ) , and vo2-max is computed using the following equations .
diagram of tuxworth - shahnavaz protocol index b y = 0.378x + 4.67 at the end of the interview , anthropometric indexes ( weight and height ) were measured .
participants with minimal clothing and no wearing shoes were weighed with a calibrated digital platform balance scale ( imperial bs 412 , us ) and the numbers were rounded to the nearest 100 g. height was measured while the participants were in standing position with the shoulders in a normal resting and also 3 regions of their body ( buttocks , heel , and head ) touching the wall , without wearing shoes .
in addition , temperature and relative humidity were measured using thermometer , spinning thermometer ( casella , england ) , and psychrometric chart .
environmental measurements indicated that the mean humidity was 52 and the mean temperature was 17c .
moreover , the noise of environment was measured using sound level meter ( model tes-1351 ) manufactured by taiwan .
the sample size was calculated to detect at least 2.3 kg change in weight with alpha value of 0.05 and a power of 80% .
data were analyzed using statistical package for social sciences 19 ( spss inc , chicago , il , usa ) .
the main study variables included both quantitative ( age , height , weight , waist circumference , body mass index [ bmi ] , and job tenure in firefighting ) and qualitative measures ( marital status , level of education , second job , and job satisfaction ) .
pearson 's correlation coefficient was used to assess the association between demographic and anthropometric variables with respiratory volume and maximal oxygen consumption .
pulmonary function tests were measured based on ats guidelines using a spirometer ( vitalograph compact ii , england ) . given device was calibrated each day and after per 10 tests .
three acceptable spirometry maneuvers , therefore , were obtained from each participant and the best one was recorded .
vo2-max was evaluated using the protocol developed by tuxworth - shahnavaz on an iranian society in 1977 . in this protocol , individuals go up and down step ( height : 40 cm ) with a cadence of 25 times in a minute for 5 min .
then , they sit on a chair , their heart rate is measured in three 30 s stages ( m1 : 3060 s , m2 : 90120 s , and m3 : 150180 s [ figure 1 ] ) , and vo2-max is computed using the following equations .
diagram of tuxworth - shahnavaz protocol index b y = 0.378x + 4.67 at the end of the interview , anthropometric indexes ( weight and height ) were measured .
participants with minimal clothing and no wearing shoes were weighed with a calibrated digital platform balance scale ( imperial bs 412 , us ) and the numbers were rounded to the nearest 100 g. height was measured while the participants were in standing position with the shoulders in a normal resting and also 3 regions of their body ( buttocks , heel , and head ) touching the wall , without wearing shoes .
in addition , temperature and relative humidity were measured using thermometer , spinning thermometer ( casella , england ) , and psychrometric chart .
environmental measurements indicated that the mean humidity was 52 and the mean temperature was 17c .
moreover , the noise of environment was measured using sound level meter ( model tes-1351 ) manufactured by taiwan .
the sample size was calculated to detect at least 2.3 kg change in weight with alpha value of 0.05 and a power of 80% .
data were analyzed using statistical package for social sciences 19 ( spss inc , chicago , il , usa ) .
the main study variables included both quantitative ( age , height , weight , waist circumference , body mass index [ bmi ] , and job tenure in firefighting ) and qualitative measures ( marital status , level of education , second job , and job satisfaction ) .
pearson 's correlation coefficient was used to assess the association between demographic and anthropometric variables with respiratory volume and maximal oxygen consumption .
environmental measurements indicated that the mean humidity was 52 and the mean temperature was 17c .
based on table 2 , more than 80% of the participants had no respiratory disorders .
accordingly , the means of fvc , fev1 , and fev1/fvc were 92% 9.4% , 87% 9.2% , and 80% 6.1% , respectively .
the mean of vo2-max was 2.79% 0.29 l / min or 37.34 4.27 ml / kg body weight per minute
. some demographic characteristics of the studied fire - fighting personnel ( n=110 ) distribution of respiratory complications among studied fire - fighting personnel ( n=110 ) mean , standard deviation , minimum and maximum lung volumes , and maximal oxygen consumption of studied fire - fighting personnel ( n=110 ) the results of table 4 show a significant association between age and peak expiratory flow ( pef ) ( r = 0.19 , p = 0.045 ) .
in addition , height was directly associated with vital capacity ( vc ) ( r = 0.23 , p = 0.016 ) , fvc ( r = 0.26 , p = 0.007 ) , and vo2-max ( r = 0.39 , p = 0.001 ) .
however , there was an inverse and significant association between height and fev1/fvc ( r = 0.23 , p = 0.017 ) .
moreover , a significant and direct association between weight and fvc ( r = 0.20 , p = 0.034 ) , pef ( r = 0.24 , p = 0.012 ) , and vo2-max ( r = 0.53 , p = 0.001 ) .
in addition , the finding revealed a significant direct association between bmi and vo2-max ( r = 0.39 , p = 0.001 ) .
finally , waist circumference showed a significant direct association with vo2-max ( r = 0.33 , p = 0.001 ) .
this is a cross - sectional study that examined the relationship between some factors linked to individuals capabilities with the cardiorespiratory factors .
moreover , considering the importance of pulmonary function tests in diagnosis and treatment of respiratory disorders , determination of normal lung volumes is essential in different societies .
in addition to lung volumes , determination of vo2-max seems to play an important role in occupational ergonomics .
however , few studies have been conducted in this area among firefighters . as a result
the aim of this study was to investigate cardiorespiratory health among firefighters in one of the central cities of fars province , iran .
accordingly , the mean of fvc , fev1 , and fev1/fvc was normal which is in accordance with the report published by michael et al . based on the sharifian 's findings ,
based on the results from a study conducted by alizadeh , height is one of the effective factors in lung volumes .
accordingly , the lower lung volumes in the present study which is not in accordance with the michael 's finding might be attributed to height differences between both societies . in the current study ,
the firefighters main complaints included shortness of breath followed by phlegm and cough , which is consistent with the findings of the study by rothman et al .
in addition , rahimi moghaddam ( 2014 ) suggested that the most frequent complaints were phlegm , wheezing , and cough among welders .
aminian also showed that cough is the most common complaint among the individuals working in textile industries .
the results of the present study showed a significant and direct association between age and pef , whereas other studies could not find such direct associations .
accordingly , significant reduction of these parameters with age is most probably due to their unprotected exposure to smoke . in the present study ,
weight , on the other hand , showed direct association with vc , fvc , and pef which are in accordance with the result of a study conducted by alizade et al .
mehrabi and kargarfard on the other hand found an inverse association between weight and lung volumes .
it could be attributed to overweight resulting from fat tissues and lack of physical activity among the participants . according to the results of the present study , participants had high bmi due to increase in their muscle mass resulting from regular physical activities .
2011 ) , excess fat tissues hinder appropriate pulmonary function that can , in turn , affect cardiovascular function .
suggested that vo2-max ranges should be from 33.5 to 42 ml / kg body weight per minute among firefighters .
however , the previous studies raised some controversial issues over the vo2-max values and suggested that certain circumstance including physical , mental , environmental , and physiological factors of different individuals might be significantly different .
role of the protocol utilized in the current study should be taken into account as well . in this study , the researchers made use of tuxworth - shahnavaz protocol that has been proposed for iranian communities . furthermore , the difference between the results of our study and the one performed by kianmehr and nazem might be attributed to the participants mean age because vo2-max decreases with increase in age and the highest amount of vo2-max has been observed in the age range of 1825 years .
results of the present study indicate a significant and direct association between height , weight , bmi , and waist circumference with vo2-max .
these results are not fully in accordance with a report published by daneshmandi et al . detected a direct but not significant association between height and vo2-max .
, the authors suggested that reduction in vo2-max decrease height due to change in muscles structure and faded the relationship between height and vo2-max . although the present study findings demonstrated a descending trend in vo2-max with increase in age , the association was not significant .
the nonsignificant association observed in the current study might be attributed to the participants small age range , which might have faded the effect of age .
furthermore , vo2-max was significantly lower in the individuals with normal bmi compared to those with high bmi
. however , the results of the study conducted by daneshmandi et al . ( 2013 ) revealed an inverse linear relationship between vo2-max and bmi ( r = 0.158 ) . what 's more , vo2-max was higher in the individuals with normal bmi in comparison to overweight and obese ones .
the ability of people to do their job is influenced by the person 's capabilities , the job demand , and the condition under which the person is carrying out the job .
the findings of this study showed that the amount of maximum oxygen consumption is close with the proposed range of this parameter among firefighters in other studies .
furthermore , the results of the study revealed that participants had normal amounts of lung volume index .
the present study was financially supported by shiraz university of medical sciences , shiraz , iran .
the present study was financially supported by shiraz university of medical sciences , shiraz , iran .
| background : firefighters for difficult activities and rescue of damaged people must be in appropriate physical ability . maximal oxygen capacity is an indicator for diagnosis of physical ability of workers .
this study aimed to assess the cardiorespiratory system and its related factors in firefighters.methods:this study was conducted on 110 firefighters from various stations .
an self - administered questionnaire ( respiratory disorders questionnaire , tuxworth - shahnavaz step test , and pulmonary function test ) was used to collection of required data .
average of humidity and temperature was 52% and 17c , respectively .
background average noise levels were between 55 and 65 db .
data were analyzed using spss software ( version 19).results : the mean age of the study participants was 32 6.2 years .
the means of forced vital capacity ( fvc ) , forced expiratory volume in 1 s ( fev1 ) , and fev1/fvc were 92% 9.4% , 87% 9.2% , and 80% 6.1% , respectively .
the participants mean vo2-max was 2.79 0.29 l / min or 37.34 4.27 ml / kg body weight per minute . the results revealed that weight has a direct association with vital capacity ( vc ) , fvc , and peak expiratory flow .
in addition , height was directly associated with vc , fvc , and vo2-max ( p < 0.05 ) .
however , there was an inverse and significant association between height and fev1/fvc ( r = 0.23 , p < 0.05 ) .
height , weight , body mass index , and waist circumference were directly associated with vo2-max.conclusions:the findings of this study showed that the amount of maximum oxygen consumption is close with the proposed range of this parameter among firefighters in other studies . furthermore , the results of the study revealed that individuals had normal amounts of lung volume index .
this issue can be attributed to the appropriate usage of respiratory masks . |
dental practice is a high risk profession and every year a large number of dentists are at risk of job related musculoskeletal disorders [ 13 ] .
different factors such as heredity , stress , unsuitable posture during work , and lack of regular exercise can affect the incidence of such disorders . in many studies of the prevalence of different musculoskeletal pains , it was reported as more than 50% [ 46 ] , but due to poor posture of upper limb [ 7 , 8 ] , repetitive movements , long term static contractions , and use of high - vibration tools , accumulation and injury in the upper limb are higher [ 11 , 12 ] .
( 2009 ) reported the majority of damage in upper limbs ( back , shoulder , and neck ) . in the study of chamani et al .
, the prevalence of pain in dentists over a year was reported to be 50.9% , 43.6% , and 37.3% in the neck , wrist , and back regions , respectively .
many studies have reported that poor posture in dentists during working is the major risk factor for musculoskeletal pain ; for example , choobineh and his colleagues , in shiraz ( 2010 ) , reported that dentists ' postures during dental work , by rula ( rapid upper limb assessment ) method , were at high risk of musculoskeletal injuries and require immediate attention and correction . in similar studies ,
saremi in tehran ( 2006 ) and varmazyar et al . in gazvin ( 2008 ) , respectively , reported that 30% and 30.2% of dentists were prone to the risk of musculoskeletal disorders by using reba ( rapid entire body assessment ) method .
a study by the american dental association ( 1997 ) showed that 9.2% of the subjects had serious upper limb damage of which 20% required surgery and 40% had to reduce their work hours .
shugars et al . ( 1984 ) reported that annually more than 41 million dollars is spent on treatment of musculoskeletal disorders in dental professionals .
each year many dentists are forced to leave their clinic , reduce their work hours , and even consider early retirement [ 1921 ] .
high treatment costs and work loss increase economic problems and decrease efficiency . due to the negative effects of musculoskeletal injuries , review and
study of injuries and musculoskeletal pain is very important , but since most previous research aimed to investigate the prevalence of musculoskeletal disorders [ 14 , 21 , 22 ] and less attention to injuries of upper limb postures and specifically to the effect of body posture , the present study aimed to assess posture versus upper limb musculoskeletal pain among dentists .
in this descriptive cross - sectional study , 130 general and professional dentists ( 84 male and 46 female ) with at least 4 years of experience and with no record of hereditary musculoskeletal disorders participated in the sample ; they used new and up - to - date equipment .
of this number , 12 subjects were excluded from the study due to their lack of cooperation or submitting incomplete questionnaires . using a demographic questionnaire ,
the personal characteristics of the subjects were recorded , including gender , age , height , weight , bmi , regular exercise pattern every week , work experience , work hours per week , and number of patients per week .
moreover , the rula ( rapid upper limb assessment ) method was used to examine the ergonomic sitting posture of the subjects .
this method was developed by mcatamney and corlett ( 1993 ) for use in ergonomic investigations of workplaces where work related upper limb disorders are reported .
this method was used several times to verify the employment status of many professions , including dentistry [ 15 , 24 , 25 ] .
rula examines the number of movements , static muscle work , and force as risk factors . at first ,
body limbs are divided into two groups : group a which includes the upper arm , lower arm , and wrist and group b which includes the neck , trunk , and legs .
the range of movement for each body part is divided into different sections and each section is numbered based on its deviation from the normal posture .
accordingly , score 1 is given to the range of movement or sitting working posture where the risk factors present are minimal , and higher scores are allocated to parts of the movement range with more extreme postures indicating an increasing presence of risk factors . if the body part is deviated from the midline or rotated , the number attributed to the posture increases .
afterwards , the scores of different body parts are combined , and given the muscular activity and the exerted force , a final score is derived which indicates the level of risk of injury ( tables 2 and 3 ) .
the ergonomic posture of subjects during sitting work is examined for 20 minutes , movements of different body parts are observed and recorded , and the worst and most frequent postures are assessed .
in addition , nordic musculoskeletal questionnaire ( nmq ) , developed by kourinka et al . ( 1987 ) , was used to examine the incidence and prevalence of musculoskeletal disorders among the subjects during the past 12 months .
the questionnaire is used as a tool for screening musculoskeletal disorders in epidemiological studies , but it can not be used for clinical diagnosis .
the questionnaire consists of two parts : ( a ) general questionnaire to answer the question of whether problems of musculoskeletal exist and if so where the focus is in the organs of the human body taking this issue into nine anatomical sites ( neck , shoulders , back , elbows , back , wrist / hand , hip / thigh , knee , and ankle / foot ) or groups and to investigate the area and its history of pain in the last 12 months or inability to leave work and the impact of these problems on the person doing deals and ( b ) specific questionnaire to provide a deeper analysis of these symptoms in certain areas of the body such as back , neck , and shoulders and career history and its impact on individual deals .
individual and job characteristics and rula scores of dentists were reported by mean , standard deviation , and frequency ; for determining relation between rula scores and symptoms of pain in the same limb , data were analyzed using logistic regression analysis ; for determining relation between symptoms of pain and variables , chi - squared test was used ; to compare two groups , women and men , we used t - test .
personal characteristics and work profile of subjects are listed in table 1 . based on data collected ,
rula scores are reported in table 2 ; the final score obtained ( 6.50 ) was most affected by the high rating of group a ( neck , shoulder , and elbow ) ( table 2 ) .
postural assessment using rula indicated that 57% of the subjects were at action level 3 ; that is , they soon required further investigation and action . further , 24.8% of the subjects required immediate change ( table 3 ) .
table 4 provides the mean rula scores based on the type of work , where surgeons and prosthodontics had the highest risk levels ( table 4 ) . to determine the relationship between rula scores and the pain that was reported for each part of the body , the nordic questionnaire logistic regression was used , and predictive values ( pv ) and confidence intervals ( ci ) at 95% significance level were used
the results of t - test between two groups , men and women , showed there was no significant difference in the final score rula ( p = 0.06 ) .
based on the data from nmq , the highest prevalence of musculoskeletal pain during the past 12 months was related to the neck ( 55.9% ) , shoulder ( 43.8% ) , waist ( 39.2% ) , wrist ( 34.5% ) , and back ( 32.5% ) regions ( table 6 ) .
based on the results presented in table 7 , frequency and prevalence of pain symptoms in women were generally more than in men , but this difference was significant only at the wrist ( p = 0.03 ) ( table 7 ) .
the results suggest that there is a significant relationship between the prevalence of musculoskeletal disorders and number of patients per week ( p = 0.02 ) and work hours per week ( p = 0.007 ) , but it was not significantly associated with gender , experience , and bmi ( p > 0.05 ) ( table 8) . moreover
, 15% of the subjects had to leave their clinic or reduce their work hours , and overall 68.9% of the subjects reported that they had experienced pain and discomfort at least once over the last year .
the numbers of patients with musculoskeletal pain of the upper limb in dentists are growing , so that the prevalence of it from 58% in 2001 has reached to 81% in 2006 . due to the increasing prevalence of musculoskeletal pain in dentists , the present research studies the prevalence and risk factors of upper limb musculoskeletal disorders in dentists .
the results of this research showed that 68.9% of the subjects reported symptoms of musculoskeletal disorders over the last year , and this prevalence of such disorders is consistent with many studies ( e.g. , 64% of the subjects in study of marshall et al .
, 64.8% , in motamayel et al . 47% , in the review article of hayes et al . , 73% of the subjects in the study of rabiei et al . , and 81.6% of the subjects in ardakani research reported it ) . these corresponded or differed with the prevalence and incidence of pain sometimes , probably due to differences between the individual and social participant .
the results also indicated that the region mostly associated with musculoskeletal disorders is the neck with a prevalence of 55.9% .
prevalence of pain in the neck and shoulder is due to the nature of dental practice . leaning forward to an angle of 15 or sometimes 30 and remaining in this posture for a long period of time along with elevating the shoulders ( with more than 30 abduction or flexion ) exerts much pressure on the neck and the shoulder [ 9 , 25 , 35 , 36 ] .
prevalence of musculoskeletal disorders was generally higher in women than men , which may be associated with the lower muscle volume and strength of women and female hormones .
however , except for the wrist , no significant gender differences were observed in musculoskeletal disorders .
the results also suggested no significant relationship between weight , bmi , and prevalence of pain , and this is consistent with the findings of lindfors et al . and chamani et al . but
indeed prolonged static contractions lead to accumulation of lactic acid , reduction of oxygen levels , and fatigue and pain .
chubine also highlighted this issue , but this finding is inconsistent with the results of marshall et al .
in the present study , oral surgeons and prosthodontics specialists were the most vulnerable groups for musculoskeletal disorders .
also in the studies of ratzan and harutunian [ 7 , 41 ] the highest prevalence of musculoskeletal disorders occurred in oral surgeons due to their more stressful work .
highest reba action level belonged to prosthodontics specialists due to their static work and oral surgeons due to their stressful work that required much concentration .
there is much inconsistency regarding the effect of the years of work on the incidence and prevalence of musculoskeletal disorders .
some studies have reported that such disorders increase with the years of work , while others have reported higher prevalence in the unskilled . in the present study , however , musculoskeletal disorders were not significantly associated with work experience .
this may be due to the fact that the majority of the subjects were young and adverse working conditions and other variables had not yet affected them .
, al wazzan et al . , choobineh et al . , and marshall et al . .
regular aerobic and stretching exercises are a key factor in preventing damage and strengthening the musculoskeletal system in dental workers [ 42 , 43 ] .
although the present study showed that musculoskeletal disorders were less prevalent in dentists who performed regular exercises , no significant relationship was observed between exercise and incidence of pain , which is consistent with the results of pour - abbas et al . and augustson and morken . in the present research , a significant relationship was observed between rula scores for different regions of the body and the pain reported by the subjects . in a similar study
, seraji found that the pain reported in different body parts was related to the working conditions associated with the same body parts , while in the research of varmazyar no significant relationship was observed between reba scores and the pain related to the same body part .
although 68.9% of the subjects reported at least one instance of upper limb discomfort over the last year , only 29.2% of them had taken action to improve or treat their disorder . in the study of harutunian ,
39.7% of dental workers were willing to investigate further , and 66.2% had taken no action to improve their problem .
reporting of the most severe pain in the neck and shoulder and the high rula grand score ( 6.50 ) indicated that the subjects were mostly affected by the high group a score ( i.e. , the neck , shoulder , and wrist ) .
lack of control over the patient , insufficient lighting , and working in a small environment with limited access force the dentist to work in a seated and forward - leaning position for long period of time with 1530 flexion which induces much stress and potential damage to the upper limbs of the dentists [ 9 , 35 , 45 ] .
the present findings showed that 15% of the subjects had to leave their clinic or reduce their work hours due to musculoskeletal disorders , and khalid et al .
( 24% ) , pour - abbas ( 11.3% ) , and saremi ( 17% ) had reported work loss and absenteeism as a result of such disorders .
high frequency of pain and high risk levels , according to the rula method , suggest inappropriate and incorrect ergonomic postural habits existing among dental professionals . since there are not any teaching or ergonomic classes in dental universities in iran , this study suggests an intervention program about work related musculoskeletal disorders that focuses on ergonomic considerations and regular exercises that can be effective in reducing such disorders . | aim .
the purpose of the present research was to examine the factors that lead to musculoskeletal disorders in dentists by assessing their posture using rula method .
materials and methods . in this cross - sectional study , 130 dentists ( 84 male and 46 female ) participated .
the posture of the subjects during their normal workload was recorded by using the rula method , and the range of musculoskeletal pains by using the nordic musculoskeletal questionnaire ( nmq ) , and individual and professional data was assessed by a demographics questionnaire .
all tests were performed at the p < 0.05 level .
results .
assessment of the physical status of the subjects showed that 82.8% of subjects were at high risk of musculoskeletal disorders .
the majority of musculoskeletal pains were in the neck ( 55.9% ) and the shoulder ( 43.8% ) .
moreover , 68.9% of the subjects had experienced pain at least once over the last year .
significant relationships were observed between musculoskeletal pain and daily work hours ( p = 0.07 ) and number of patients ( p = 0.02 ) , but the pain was not significantly associated with bmi and experience . conclusion .
the present findings showed that unsuitable posture of dentists during work has a considerable effect on musculoskeletal disorders .
therefore , further investigation is required to avoid the detrimental effects of wrong posture . |
the accuracy of translation initiation site ( tis ) prediction in prokaryotes is still not sufficient .
though existing gene finders may reliably identify coding regions of significant length , they usually show a poor performance in predicting the correct tiss ( 13 ) . for genomes with a high g+c content in particular ,
recently , several postprocessors have been proposed ( 1,2,4,5 ) to improve the accuracy of tis prediction in prokaryotic genomes .
our tool tico ( for tis corrector ) is based on an unsupervised learning scheme for relocation of putative gene starts .
the underlying tis model is very general and does not include any specific assumptions about tis - related sequence features . in particular , no a priori assumptions about shine
dalgarno ( sd ) motifs ( 6 ) and their positional and compositional variation are required .
in addition , we avoided any kind of empirical thresholds which might also imply a severe bias towards certain genomes . despite the generality of the implemented method ,
the prediction performance of our program is competitive ( 7 ) , with good results even on high - g+c genomes . the program is supplemented with a tool for visualizing relevant sequence features which have been learned by the algorithm .
this extension provides an effective means for monitoring the resulting model and may also reveal unknown sequence characteristics associated with prokaryotic tiss .
the algorithm implemented in the tool tico is based on a constrained clustering scheme which we described in detail in ( 7 ) .
the clustering starts with an initial gene annotation given as input . within a specified search range around each annotated
these candidates have to share the reading frame of the annotated open reading frame ( orf ) without any in - frame stop codon occurring between a potential start and the annotated stop . at the start of the clustering
, the initially annotated gene starts are labelled as strong tiss ; all other candidates are labelled as weak tiss .
based on that labelling , a positional weight matrix ( pwm ) is estimated from position - dependent trinucleotide frequencies .
then the pwm is used to score the candidates and , in turn , the score is used to reassign the candidates according to strong and weak tis categories . among all candidates associated with an orf , the candidate with the maximum positive score is labelled strong ; all other candidates of that orf , are labelled weak .
estimation of the pwm is repeated until the labels no longer change or a maximum of 20 iterations has been reached . as the clustering algorithm requires a suitable initialization , the resulting prediction to some degree depends on the prior annotation of tis locations used for the initial labelling . in comparison with other tools
our algorithm has proven to be rather robust with respect to low accuracy of the initial annotation ( 7 ) .
nevertheless , the quality of the initial annotation can be too bad to serve as an appropriate starting point for our algorithm . also , in cases where no tis - related signals are actually present in the sequence , our algorithm is unlikely to improve the prediction .
tico can be accessed through our web interface and it is also available as commandline tool for linux and windows .
the tool requires the input of a genome sequence in the fasta format and a valid gene annotation , as obtained , for example , using the tool glimmer ( 8) . the current version accepts two kinds of input format : glimmer2.x and our own format called
simple coord. in the download section , several perl scripts are available for conversion of other formats ( e.g. the ptt format provided by genbank ) into the tico input format .
the output of the tool is provided in a glimmer - like format , in our own format and in general feature format ( gff ) , according to the specifications of the sanger institute ( ) .
all formats contain the gene coordinates as predicted by tico and a score which indicates the quality of the predicted tis , i.e. a measure of fit with respect to the model resulting from the clustering algorithm . in gff and the glimmer - like format the relocations of the tis are also represented by means of the distance between the initially annotated position from the input and the new position for the tis as predicted by tico .
in addition , one or several output formats have to be selected and an email address has to be provided to receive the results . the commandline version is applicable to annotation pipelines and it is executable on a common desktop pc . the user interface has been implemented in java and can be configured by means of a properties file or via commandline parameters .
since the first version of tico was published ( 9 ) a number of extensions have been added .
the most important extensions include an automatic adaptation of the smoothing parameter sigma ( 7 ) and the visualization of the pwm features , which is detailed in the next section .
the latest version of tico provides a companion tool for visualization of the discriminative features learned for the classification of tis candidates . the basis for the visualization
the corresponding weights specify how trinucleotide occurrences within the sequence window contribute to the score used for labelling of tis candidates .
if a certain trinucleotide occurrence within that window is associated with a high positive weight , the occurrence provides evidence for a strong tis .
similarly , a high negative weight provides evidence for a weak tis . in the current implementation , the visualization of learned characteristics is realized by transforming the pwm into a colour image ( figure 2 ) . in the resulting pwm image
, colour represents the weight value associated with a certain trinucleotide ( row ) at a specific position ( column ) .
high positive and high negative weights result in red and deep blue spots , respectively .
a colour scale at the right of the pwm image displays the colours associated with certain weight values . to obtain more precise information about the weights
, the numerical value can be accessed by clicking on the corresponding image location . in that context
, a zoom function may be used for close inspection of the weights . by means of the visualization of the pwm
, the resulting tis model can be interpreted by the user . in combination with biological background knowledge
figure 2 , for example , shows a visualization of the weights calculated for escherichia coli .
dalgarno sequence of e.coli has been proposed to contain the pattern aggag ( 6 ) 12 to 4 nt upstream of the translation start ( 10 ) . in accordance with these findings ,
the image shows high positive weights for the trimers agg , gag , aga and gga at positions 12 to 7 .
also , a slight positive maximum for the trimer aaa immediately following the start codon is observable .
such a triple - a downstream box has been proposed to provide another tis - related signal ( 11 ) , which has been confirmed in ( 12 ) .
we should point out that the visualization of pwms is only useful if strong tis - related signals are actually present in the data .
if statistically significant signals can not be found in the sequence , no characteristic features will be observable .
however , weak signals with bad visibility in the pwm image do not automatically imply a bad prediction of tis locations .
although for several high - g+c genomes the resulting pwm images show a bad signal - to - noise ratio , in many cases the prediction of tis can nevertheless be improved considerably using our algorithm ( 7 ) .
the performance of tico has been tested on the genomes of e.coli and bacillus subtilis , as well as on the high - g+c genomes of pseudomonas aeruginosa , burkholderia pseudomallei and ralstonia solanacearum .
using these genomes is reasonable because for the corresponding organisms a reliable gene annotation is available .
the results in comparison with other recent tools for improvement of tis prediction can be found at .
a detailed comparison of our tool with the tools rbsfinder ( 4 ) , med - start ( 2 ) and gs - finder ( 1 ) has been published in ( 7 ) .
the user may choose one or more output formats and should give an email address to receive the results .
in addition , some optional parameters can be adjusted , including the range of extracted sequences around the start candidates .
visualization of the pwm calculated for e.coli using the default settings . on the horizontal axis
the position within the sequence window is denoted ; on the vertical axis trinucleotides are denoted in alphabetical order .
the upstream and downstream regions are represented by negative and positive position indices , respectively . | exact localization of the translation initiation sites ( tis ) in prokaryotic genomes is difficult to achieve using conventional gene finders .
we recently introduced the program tico for postprocessing tis predictions based on a completely unsupervised learning algorithm .
the program can be utilized through our web interface at and it is also freely available as a commandline version for linux and windows .
the latest version of our program provides a tool for visualization of the resulting tis model .
although the underlying method is not based on any specific assumptions about characteristic sequence features of prokaryotic tis the prediction rates of our tool are competitive on experimentally verified test data . |
keratocystic odontogenic tumor ( kcot ) , is regarded as a developmental abnormality and is generally known for its aggressive nature and high recurrence rate , especially in comparison with other developmental odontogenic cysts .
in addition to a distinctive biological behavior , the expression of various proliferation markers in the epithelial lining and mutations in p53 and patched genes ( tumor suppressor genes ) have led several investigators to consider kcot as a benign cystic neoplasm.1 ameloblastoma ( am ) is a locally invasive benign epithelial odontogenic tumor that may arise from rests of dental lamina , enamel organ rests , cell rests , the epithelial lining of an odontogenic cyst or from the basal cell layer of oral mucosa.1 it is considered as the most common benign epithelial odontogenic tumors , which are locally invasive tumor that has a tendency to grow continually and invade the surrounding tissues.2 the dentigerous cyst ( dcs ) is the common odontogenic cysts , which is of developmental in origin and is suggested to be caused by accumulation of exudate between the tooth crown and reduced enamel epithelium , which demonstrates an indolent behavior and seldom recurs following removal.1,2 the kcots , similar to dcs , appear as cystic lesions , but their invasiveness and destructive growth are comparable to am . it has been suggested that unknown factors integrated in the epithelium or fibrous capsule of kcots may be responsible for their specific biological behavior.1 the connective tissue stroma has an essential role in preservation of epithelial tissues and minor alterations in the epithelium , which are followed by corresponding changes in the stroma , such as angiogenesis.1 blood supply is an essential factor for the growth of odontogenic epithelium . because there is no vascular system in the epithelium
, apoptosis will happen if the connective tissue does not provide the necessary blood supply .
myofibroblasts ( mf ) , blood vessels , and inflammatory cells are present in the tumoral stroma .
the invasion and metastasis of tumors requires the presence of mf and blood vessels , which increases during tumorigenesis.3 neoplastic tissues require oxygen and nutrients for survival and growth ; therefore , they induce the formation of new blood vessels through angiogenesis or neovascularization.1,4 angiogenesis is the growth of new blood vessels from pre - existing vessels , which is a physiological process , like cancer it is a complex multi - stage process , including degradation of extracellular matrix , proliferation and migration of endothelial cells , capillary differentiation and anastomosis.3 there is a large spectrum of physiological and pathological processes in which angiogenesis occurs , ranging from tissue hypertrophy , wound healing , and inflammation to tumours.2 folkman showed preliminary evidence that tumors could not enlarge beyond 1 - 2 mm diameter without recruiting new capillary blood vessels ( microvessels).5 an ideal marker for angiogenesis should detect the newborn vessel for its quality as well as its quantity .
tumor angiogenesis is regulated by various molecules such as vascular endothelial growth factor ( vegf ) , cd31 , cd34 , von willebrand factor , and cd105 , also called as endoglin .
legan stated that pan - endothelial markers ( cd31 , cd34 , factor viii ) and cd105 are differentially expressed in angiogenic and normal vessel endothelial cells.2,6 cd105 is a component of the receptor complex of transforming growth factor ( tgf - b ) , which is disulfide glycoprotein that modulates angiogenesis by the regulation of different cellular functions .
the expression of cd105 predominantly restricted to vascular endothelial cells on which majority levels of proteins are detectable , whereas it is scarcely expressed on lymphatic endothelial cells .
cd105 expression is a prominent feature of newly formed blood vessels , but minimally expressed in pre - existing tumor vessels .
cd105 have shown greater specificity for the tumor vasculature than pan endothelial markers.2,7,8 in odontogenic cysts and tumors , the connective tissue stroma has an essential role in the preservation of epithelial tissues and minor alterations in the epithelium are followed by corresponding changes in the stroma , such as angiogenesis.3,9 in the present study , we intend to evaluate and compare microvessel density ( mvd ) in kcots , dcs and am using monoclonal antibody against cd105 .
a total of 70 archival specimens which were formalin fixed , processed and embedded tissues of prediagnosed 20 cases of sa ( group a ) , 20 cases of kcot ( group b ) , 20 cases of dc ( group c ) and 10 cases of pyogenic granuloma ( control group ) were retrieved from the department of oral pathology and microbiology , government dental college and research institute , bangalore by random sampling .
all the archival specimens that had been previously diagnosed as am ( only solid multicystic variant , no unicystic variant ) ; kcot and dc with no history of malignancy either orally and systemically were included in the study group .
the study was approved by institutional review board of government dental college and research institute , bangalore .
the presence and frequency of microvessels were then assessed by observing the slides under the light microscope .
vascular endothelial cells which were stained by cd105 , clearly identified by their brown cytoplasmic staining . based on the criteria of weidner et al .
1991 , highlighted endothelial cell or a cell cluster clearly separate from adjacent microvessels and other connective tissue elements was regarded as a distinct countable microvessel .
mvd quantification was carried out using an bh2 microscope olympus according to the method suggested by weidner et al .
( 1993).10,11 10 areas with the highest amount of vascularization ( hotspots ) were selected under a magnification of 100 ( 10 ocular and 10 objective ) .
microvessels were counted in each of the 10 fields at 400 magnifications ( 10 ocular and 40 objectives ) and the mean density was reported .
all slides were simultaneously evaluated by two observers using a double - headed microscope , and both had to agree on each of the individual microvessel before being included in the count .
the field size for 400 magnification ( 40 objectives and 10 ocular ) was approximately 0.18 mm . for cystic lesions ,
the fields were selected immediately beneath the cystic epithelium lining and for solid am it was selected immediately adjacent to the tumoral islands / nests / cords .
bonferroni method was employed for the adjustment of p value in multiple comparisons and p < 0.05 was considered as significant . the statistical package for social sciences ( spss 14 ) software was used for computations .
vascular endothelial cells which were stained by cd105 , clearly identified by their brown cytoplasmic staining . based on the criteria of weidner et al . 1991 , highlighted endothelial cell or a cell cluster clearly separate from adjacent microvessels and other connective tissue elements was regarded as a distinct countable microvessel .
mvd quantification was carried out using an bh2 microscope olympus according to the method suggested by weidner et al .
( 1993).10,11 10 areas with the highest amount of vascularization ( hotspots ) were selected under a magnification of 100 ( 10 ocular and 10 objective ) .
microvessels were counted in each of the 10 fields at 400 magnifications ( 10 ocular and 40 objectives ) and the mean density was reported .
all slides were simultaneously evaluated by two observers using a double - headed microscope , and both had to agree on each of the individual microvessel before being included in the count .
the field size for 400 magnification ( 40 objectives and 10 ocular ) was approximately 0.18 mm . for cystic lesions ,
the fields were selected immediately beneath the cystic epithelium lining and for solid am it was selected immediately adjacent to the tumoral islands / nests / cords .
bonferroni method was employed for the adjustment of p value in multiple comparisons and p < 0.05 was considered as significant . the statistical package for social sciences ( spss 14 ) software was used for computations .
in am , islands of odontogenic epithelium were surrounded by layers of cd105 positive vessels ( figure 1 ) .
endothelial cells showing fine cd105 positivity were located beneath and parallel to the basement membrane of the odontogenic epithelium of the cystic lesions ( figures 2 and 3 ) . whereas , the expression of cd105 is diffuse in pyogenic granuloma , which is taken as control ( figure 4 ) .
cd105 positive microvessels adjacent to the epithelial islands in ameloblastoma ( original magnification 200 ) .
microvessels beneath the epithelium in keratocystic odontogenic tumor expressed by cd105 antibody ( 200 ) .
am and kcot demonstrated a higher mean value of 7.98 ( 2.70 ) and 6.25 ( 2.88 ) respectively while dc demonstrated a lower mean of 3.75 ( 1.42 ) .
there was no statistically significant difference between am and kcot ( p > 0.05 ) .
the difference between am and dc ; and between kcot and dc was statistically significant ( p < 0.05 ) .
when am , kcot and dc were compared with pyogenic granuloma , the mean number of microvessels per field in pg was statistically significant from that of am , kcot and dc ( p < 0.05 ) ( table 1 ) .
odontogenesis is controlled by interactions between the epithelial and mesenchymal components of developing dental tissues .
regarding the fact that odontogenic cysts and tumors arise from tissue remains of odontogenesis , these interactions have been considered to play an important role in the tumorigenesis of odontogenic lesions .
the connective tissue stroma has an essential role in preservation of epithelial tissues and minor alterations in the epithelium are followed by corresponding changes in the stroma , such as angiogenesis.2 in embryogenesis vasculogenesis is one of the earliest events .
mesodermal cells differentiate into hemangioblasts , progenitors of both endothelial cells and hematopoietic giving rise to blood vessels in the early part of embryonic development . after further differentiation , hemangioblasts produce angioblasts , aggregation of which results in the formation of blood islands .
blood islands , which are fused results in appearance of the primary blood vascular plexus consisting of fine capillaries formed by endothelial cells.12 an ideal marker for angiogenesis should detect the newborn vessel for its quality as well as its quantity .
tumor angiogenesis is regulated by various molecules such as vegf , cd31 , cd34 , von willebrand factor , and cd105 , also called as endoglin .
legan stated that pan - endothelial markers ( cd31 , cd34 , factor viii ) and cd105 are differentially expressed in angiogenic and normal vessel endothelial cells .
the expression of cd105 is predominantly featured on newly formed tumor vessels but minimally expressed in quiescent pre - existing tumor vessels .
cd105 have shown greater specificity for the tumor vasculature than pan endothelial markers.3,4,13 the am is characterized by local invasiveness and recurrence .
various stromal factors , like growth and angiogenic factors , extracellular matrix components and proteinases play an important role for the invasion , growth and progression of tumors .
several authors have shown that the elevated expression of matrix metalloproteinases 2 ( mmp 2 ) , mmp 9 , tgf - b , fibronectin , tenascin , stromal mf is related to the invasive behavior of am .
these findings are well supported by significantly increased mvd in am compared with kcot and dc in our study.2,14,15 the kcots , similar to dcs , appear as cystic lesions , but their invasiveness and destructive growth are comparable to am . it has been suggested that unknown factors integrated in the epithelium or fibrous capsule of kcots may be responsible for their specific biological behavior .
microscopic epithelial and stromal features have been the center of attention in several investigations comparing kcots , dcs and ams . in our study
, there is a significant difference in angiogenesis between kcots , dcs and solid ams .
the highest mean mvd in the studied lesions was observed in am , followed by kcot and dc . on the other hand , when treatment is based on enucleation , the recurrence rates of these lesions have been reported as 50 - 90% in solid ams , 17 - 56% in kcots , 30.5% in uas and usually none in dcs .
( blanas et al . , 2000 ; lau and samman , 2006 ; neville et al . , 2008 ) .
therefore , it seems that angiogenesis may be associated with the different biological behaviors of these lesions and at least to some degree can reflect their clinical features .
this suggests that the angiogenesis have an important role in tumor progression and invasiveness of am .
increased angiogenesis in kcot may contribute to the locally aggressive biological behavior.4 assessment of tumor angiogenesis may prove very valuable in predicting response to anti - angiogenic therapeutic strategies and also provide an objective assessment of post therapeutic response particularly in recurrent cases of am and kcot .
the findings of the present study indicated that the aggressive nature and locally invasive growth pattern of am can be positively correlated to the cd105 expressed mvd . though kcots appear as cystic lesions , but their invasiveness and destructive growth are comparable to am . thus our results do support the previous studies .
further investigation and studies in this field with a note on the treatment prospective will help in establishing the role of angiogenesis in the biological behavior of odontogenic lesions .
newer modalities of treatment like anti - angiogenic therapeutic agents can be used prior to surgical removal of these lesions in order to reduce the tumor size and postoperative morbidity because curative surgery of particularly aggressive odontogenic lesions could occasionally result in significant functional , esthetic and psychological damage . | background : demonstrate the expression of cd105 ( angiogenetic marker ) in ameloblastoma ( am ) , keratocystic odontogenic tumor ( kcot ) and dentigerous cyst ( dc).material and methods : assessment of microvessel density ( mvd ) in 70 cases , including 20 kcot , 20 dc and 20 solid ams .
assessment of mvd should be done as the mean number of microvessels per high-power-field.results:am and kcot demonstrated a higher mean value of 7.98 ( 2.70 ) and 6.25 ( 2.88 ) respectively while dc demonstrated a lower mean of 3.75 ( 1.42 ) .
there was no statistically significant difference between am and kcot ( p > 0.05 ) .
the difference between am and dc ; and between kcot and dc were statistically significant ( p < 0.05).conclusion : the present study suggested that angiogenesis may be one of the mechanisms possibly contributing to the different biological behaviors of kcot , dcs and solid ams . |
paget 's disease ( pd ) of the bone was first described , in 1877 , by sir james paget under the term osteitis deformans .
it is characterized by rapid bone resorption and deposition , resulting in formation of numerous reversal lines , which give rise to a mosaic pattern in the lamellar bone with profuse local vascularity and fibrous tissue in the marrow . in the initial phase of pd
however , both may occur simultaneously , resulting in osteoporosis and sclerotic bone . within the sclerotic bone
there is reduced vascularity ( localized vascularity ) and the ability for normal healing is compromised , hence it can lead to osteonecrosis .
therapeutic agents for pd include bisphosphonates like alendronate , risedronate , and zoledronic acid . a 70-year - old male patient presented with a 3-month history of perforation in the left maxillary region with drainage of oral fluids from the nasal cavity .
extra - oral examination showed localized hyperthermia with enlarged cranium , zygoma , and incompetent lips [ figure 1 ] .
intraoral examination showed enlarged maxilla , fistulous tract connecting posterior maxilla and maxillary sinus , and ill - fitting temporary partial denture in relation to left maxillary molars [ figure 2 ] .
70-year - old male with perforation in the left maxillary region diagnosed with paget 's disease .
extra - oral clinical photograph shows enlarged cranium , zygoma , and incompetent lips ( arrows ) .
70-year - old male with perforation in the left maxillary region diagnosed with paget 's disease .
pd of the bone is diagnosed primarily by radiographic examination . early in the course of the disease
subsequently , areas of sclerosis develop leading to the characteristic appearance of mixed lytic and sclerotic areas , thickened trabeculae , bone expansion , cortical thickening , and deformity .
generalized mixed radiolucent and radiopaque areas were seen in the maxilla and mandible with characteristic cotton wool appearance in the left maxilla [ figure 3 ] .
paranasal sinus view revealed generalized increase in the fuzziness of all the facial bones with mixed radiolucencies in the frontal bones and marked haziness in the maxillary sinuses .
lateral skull view showed generalized mixed radiolucent and radiopaque areas suggestive of pagetic calvaria [ figure 4 ] .
70-year - old male with perforation in the left maxillary region diagnosed with paget 's disease .
panoramic radiograph shows generalized mixed radiolucent and radiopaque areas in the maxilla and mandible ( arrows ) with characteristic cotton wool appearance in the left maxilla .
70-year - old male with perforation in the left maxillary region diagnosed with paget 's disease .
lateral skull view shows generalized mixed radiolucent and radiopaque areas ( arrows ) suggestive of pagetic calvaria .
histopathology of the lesion showed increased osteoblasatic activity and hematoxyphilic reversal lines giving an appearance of the characteristic pagetoid bone .
marrow spaces were filled with fibrous connective tissue , confirming osteitis deformans [ figure 5 ] .
biochemical analysis showed abnormal increase ( 740 u / i ) in serum alkaline phosphatase enzyme level ( normal range is 40 - 125 u / l ) and urinary hydroxylproline ( 88 mg / day / m ) .
70-year - old male with perforation in the left maxillary region diagnosed with paget 's disease .
hematoxylin and eosin stained biopsy tissue ( 100 ) shows immature bone either with osteoid and osteoblastic rimming , reversal lines , and enough fibrovascular stroma ( arrow ) .
on correlating the clinical , radiographic , histopathological , and biochemical findings , it was finally diagnosed as a case of pd involving the maxilla and skull .
an obturater was placed in the left maxillary ridge to prevent draining of oral fluids into the nasal cavity [ figure 6 ] .
70-year - old male with perforation in the left maxillary region diagnosed with paget 's disease .
intraoral clinical photograph shows an obturator ( arrow ) placed in the left maxillary molar region .
pd is a relatively common disease in western countries ; it is very rarely encountered in the indian population .
it occurs mostly in the fifth to sixth decade of life , with a high preponderance in the male population .
the etiology of pd is still not totally clear , but genetic and environmental factors may play a role .
pd may affect the jaw bones , cementum of the teeth and pulp tissue , which lack cellular structure with manifestation of interglobular dentine . in our case altered size and shape of the maxilla , osteonecrosis that resulted in a fistulous tract , radiographically hypercementosis , displacement of the teeth , and cotton wool appearance in both the jaws were evident .
non - healing extraction sites and exposed alveolar bone following the removal of maxillary teeth in a patient with advanced pd has been reported . a case of chronic osteomyelitis involving the maxilla following dental extractions in a pagetoid patient
a total of 63 cases of bisphosphonate - induced osteonecrosis of the jaws were reported ; majority of the cases affected the maxilla . in the clinical scenario ,
the question posed is whether osteonecrosis in postoperative sites occurs as a result of pd , bisphosphonate therapy , or a combination of the two . in both ,
but , in our case there was no evidence of any non - healing socket and the patient had not used any medication to treat pd .
the patient was referred to a physician for treatment of pd , who prescribed alendronate 40 mg / day for 6 months .
drug induced osteonecrosis in paget 's disease is common . in the present case , osteonecrosis secondary to paget 's disease (
non - drug induced ) seen in a 70-year - old male patient shows characteristic radiographic and pathologic features of paget 's disease . | paget 's disease ( pd ) is a chronic progressive disease of the bone characterized by abnormal bone metabolism affecting either a single bone ( monostotic ) or many bones ( polyostotic ) with uncertain etiology .
we report a case of pd in a 70-year - old male , which was initially identified as osteonecrosis of the maxilla .
non - drug induced osteonecrosis in pd is rare and very few cases have been reported in the literature . |
houston , texas , is a metropolis in the southeastern united states with around four million residents .
west nile virus ( wnv ) human cases were first reported locally in 2002 and have since become endemic with human cases reported annually .
wnv is an arboviral disease from the flaviviridae family whose main transmission cycle occurs between birds and mosquitoes ; humans serve as an incidental host . in southeastern united states ,
culex quinquefasciatus mosquitoes have been demonstrated as important vectors of wnv disease transmission [ 2 , 4 ] . in the united states ,
wnv transmission season traditionally occurs from spring to fall , with a peak in late summer . in warm weather ,
mosquito larval development occurs within days [ 5 , 6 ] allowing for rapid reproduction of new mosquito populations .
mosquito larval development occurs in water bodies with each species having their own preferential type .
culex quinquefasciatus mosquitoes have a diverse larval habitat range , with high larval counts near human habitation [ 7 , 8 ] .
mosquito control efforts in houston , texas , target residential areas where either mosquito pools or dead birds are positive for wnv disease .
targeted areas are identified through random mosquito trapping and reporting of dead birds by residents .
the ecological dynamic between vector , reservoir , and human habitats is critical to understand when examining risk for human wnv infection .
while this vector 's larval habitat preferences are known , no studies to date have examined direct associations between larval water habitats and wnv human disease transmission .
this paper presents a novel method for examining disease clustering and its spatial association with water sources .
a case - control study design was used to determine the association between water sources and the risk of human infection with wnv .
cases were defined as wnv - positive patients identified through local surveillance performed by the houston department of health and human services ( hdhhs ) , harris county public health and environmental services ( hcphes ) , or the gulf coast regional blood center ( gcrbc ) .
local surveillance identified cases either by state mandatory reporting laws or by national blood donation testing guidelines that required laboratory confirmation of wnv human disease .
previous research has shown that the highest rates of wnv human seroprevalence were among those who reported a history of being outside during the hours of dusk and dawn .
these hours are concurrent with the peak activity time of culex quinquefasciatus mosquitoes . since most people are at home during dusk and dawn , it was resolved that cases are most likely exposed while at home .
it was determined appropriate to use cases ' home address at time of disease development as their location of mosquito exposure .
cases ' home addresses were collected via case investigations performed by hdhhs , hcphes , or gcrbc during 2002 and 2009 .
exclusion criteria included evidence of nonlocally acquired disease as documented in the case investigation nonrecognition of address by mapmarker usa version 14 geocoding software , or home address falling outside the metropolitan 's geographic area as determined by the geocoding software .
after applying the exclusion criteria , we had 356 residential addresses from cases for final analysis .
controls were defined as selected block centroids generated from the united states census bureau decennial data ( http://www.census.gov/ ) .
controls were selected using two methods : a population proportionate to size sampling method which takes into account varying population densities within the metropolitan city and a random sampling method .
there were three selection frames that were used to identify the final control . in descending order
the population proportionate to size sampling methods was used to select the initial frame : census tract level .
it was understood that population distribution was uniform throughout the census tracts selected ; therefore , we used a random selection method for the two additional frames : block group and block .
since the smallest defined census level is a block , the centroid of the block level was used as a surrogate for control households .
based on sample size calculations , a 1 : 1 case - control ratio was determined appropriate to satisfy statistical significance using discipline standards ; therefore , 356 control addresses were selected for final analysis .
spatial analysis of case and control residential distances ' to local water body sources was performed using mapinfo v9.5.1 software .
shapefiles of water sources within the metropolitan 's geographic parameters were provided in kind by dr .
water source labels were used to identify the particular water source , that is , cedar spring , lou river , brays bayou , and so forth .
the water source type was inferred from these labels . using the software 's measurement tool
, we measured the distance from each case / control point , to the closest water source , excluding salt water sources since culex quinquefasciatus mosquitoes do not utilize salt water sources as larval habitats . for each case / control point we recorded the proximity to the closest water source , the type of the particular water source , and the name of the particular water source .
we used stata v11.0 ( college station , texas ) to run all statistical analyses .
chi - squared tables and logistic regression were used to analyze the significance of proximity to a water source between the two populations .
odds ratios , 95% confidence intervals ( cis ) , and p values were computed to analyze the significance of three factors : specified residential proximity to a water source ; proximity to a particular water source type ; proximity to a particular water source .
attack rates ( number of wnv human cases over total number of households ) were calculated for each census tract and mapped to spatially identify areas of high wnv human transmission .
a getis ord hot spot analysis was performed using esri arcgis 10.0 to determine concentrations of high and low human disease clustering .
the getisord ( gi ) hot spot analysis identifies clusters of higher and lower magnitude than would be randomly found and statistical output is in the form of a z score known as a giz score .
areas of high clustering were indicated by a giz score of 1.96 or greater , and areas of low clustering were indicated by a giz score of 1.96 or less .
on average , cases and controls resided the same proximity from water sources [ x0 ( controls ) = 892 meters , x1 ( cases ) = 931 meters ] . using linear regression
, we found no statistical association between residential proximity to water and odds for human wnv infection .
however , when we binomiallycoded at varying distances ranging from 50 to 750 meters , we found a significant protective trend from distances ranging from 50 to 200 meters ( table 1 ) .
living less than or equal to 200 meters from a water source ( x = 6.67 , p < 0.01 ) was found to be protective from infection by a factor of 0.54 .
water source types were analyzed for association with odds for human wnv infection using odds ratios and chi - squared tests , as seen in table 2 .
living near a creek increased one 's odds of human infection by a factor of 1.37 ( p = 0.09 ) . living near a spring decreased one 's odds of human infection by a factor of 0.55 ( p = 0.06 ) . to further analyze these associations , we created two groupings based on slow moving and moderate moving water source types .
a grouping of slow moving water bodies ( creeks and gullies ) was found to increase one 's odds of human infection by a factor of 1.45 ( p = 0.03 ) .
a grouping of narrow moderate moving water bodies ( streams and rivers ) was found to be protective against human infection by a factor of 0.50 ( p = 0.02 ) .
particular water sources were evaluated for association with odds for human wnv infection by odds ratios and chi - squared tests , as seen in table 3 .
living close to white oak bayou ( p = 0.01 ) increased one 's odds of human infection by a factor of 2.25 .
additionally , living near cypress creek ( p = 0.02 ) was also associated with increased odds of human infection by a factor of 2.54 . since
cypress creek has several tributaries , an additional category was made that included all feeders for cypress creek .
this group had the strongest significance of all water bodies ( p < 0.01 ) with increased odds of human infection by a factor of 1.93 .
we also found that living close to buffalo bayou had increased odds of human infection by a factor of 1.59 , which neared significance ( p = 0.07 ) .
spatial distribution of wnv attack rates per 10,000 population by census tract illustrates that the highest risk area of transmission is in northwest houston as seen in figure 1 . hot spot analysis
confirmed that there were significant clusters of cases in houston as seen in figure 2 .
the areas of highest valued clusters were along the northwest corner of harris county , which overlaps cypress creek and its feeders .
figure 3 demonstrates the spatial relevance of the houston area inlaid within harris county , in relation to the state of texas , and the united states of america .
this is the first known case - control study to perform a spatial analysis of human wnv infection risk with regard to proximity of residences to water sources serving as surrogates for potential aquatic larval habitats .
overall , we found no direct association between proximity of residences to water sources and odds of wnv human infection in houston , texas .
however , we found a significant trend of decreased risk of infection among people living within 200 meters of a water source .
it is conjectured that areas closest to water sources are the primary target of mosquito control programs , therefore decreasing the risk of transmission at closer distances .
we did find a pattern of increasing odds ratios as distance increased by 50-meter intervals , suggesting that mosquitoes in houston have an expansive flight range that is important in the ecology of disease transmission .
culex quinquefasciatus mosquitoes are known to have an expansive flight range with recapture documented up to 1000 meters outside of their release site .
one speculation could be that the use of adulticides along water bodies could temporarily suspend adult mosquito activity allowing for higher mosquito activity occurring at greater distances .
although adulticides are the primary mosquito control method used in this area , it is known that the use of adulticides is random and not associated with specific water bodies .
another speculation is that alternate breeding sites , specifically storm sewers , also play a role in disease transmission . in houston ,
culex quinquefasciatus are the dominate mosquito species collected from storm sewers , and storm sewers have been demonstrated as a preferential site for breeding , larval development , and daytime resting .
unfortunately , we did not have access to sewer blueprints of the metropolitan area to further investigate this theory .
when analyzing residential proximity to water source types , we did find a strongly significant association for risk of human infection among residences near creeks and gullies , specifically cypress creek .
it is believed that the slower movement of water and dense vegetation is preferential for the local transmitting culex vector species .
due to low numbers of cases per creek , no additional specific creek sources were included in the final analysis .
cypress creek is a large water source that flows throughout the northwest corner of the metropolitan houston area .
figure 1 demonstrates that attack rates of human infection are strongest in the area where cypress creek flows .
this finding is further substantiated by figure 2 , which shows the highest clusters of human wnv cases are in the area where cypress creek flows .
we feel the true association of infection is with the particular water source cypress creek .
additional studies should perform mosquito pool testing around cypress creek and additional creeks and gullies throughout the metropolitan area to examine wnv field infection rates of mosquitoes in efforts to further validate our findings .
when analyzing residential proximity to water source types , we did find a strong protective association of residences closest to streams ; however , no particular stream water sources were identified as being associated with infection . to further investigate these findings
, we created a grouping of moderate moving water sources which included streams and rivers .
these findings are evidence that residences in closest proximity to moderate moving water sources are significantly protected against wnv human infection .
houston is prone to flooding , and as part of the flood mitigation program , the city has an extensive network of bayous , which are man - made canals .
the surrounding habitats of bayous in houston are varied with some being cast with concrete walls and others edged with grass , shrubs , and other vegetation .
overall , we did not find an association between the living near bayous and increased odds of infection .
however , we did find that white oak bayou and buffalo bayou were significantly associated with increased odds of infection .
this is in sharp contradiction to the bayous lined with concrete , such as brays bayou , where the data suggested decreased odds of infection .
one limitation was the potential for selection bias due to the inability to verify disease status of controls by serum antibody testing .
since wnv is a mandatory - reportable disease in the state of texas , anyone who tested positive should have been reported to the local health department .
the risk of misclassification of controls is possible if a resident at the address never developed symptoms or had mild disease that went undiagnosed as wnv .
however , this risk is presumed minimal since current estimates of seroprevalence in houston are relatively low . due to financial constraints
, we were unable to obtain a serum sample from controls to verify disease status .
lastly , we were unable to test for potential confounders related to human - mosquito transmission , such as socioeconomic status , gender , rainfall , or other seasonal environmental factors .
complete records for these potential confounders were unavailable . despite the inability to control for these potential confounds
, we believe the results are sound considering people do not choose their residence location based on human - mosquito transmission hotspots . the main strength of the study is the ability to determine high risk areas of wnv transmission around the houston metropolitan area using minimal resources .
the methods we used are simple to perform and could be of benefit to health authorities in other jurisdictions to identify areas with increased risk for wnv transmission . in resource - scarce public health departments , this inexpensive method could greatly increase the effectiveness of mosquito control programs .
since wnv is a reportable disease nationally , case investigations are performed for all patients that test positive . from these case investigations ,
control selection would be easy to execute as census data is readily available from the us census bureau website that is updated both annually and decennially . in conclusion , we found that living near slow moving water bodies , such as creeks and gullies , or bayous with heavy vegetation increased one 's odds of infection with wnv .
most importantly , we identified cypress creek as an area of high wnv human infection that should be targeted by future mosquito control efforts . with the recent literature suggestive of increased ranges of arboviral vectors and areas of transmission ,
this method of spatial analysis could benefit other health authorities in areas experiencing active wnv transmission who need predictive models of exposure risk for targeted education and control efforts for disease prevention . | west nile virus ( wnv ) , a mosquito - borne virus , has clinically affected hundreds of residents in the houston metropolitan area since its introduction in 2002 .
this study aimed to determine if living within close proximity to a water source increases one 's odds of infection with wnv .
we identified 356 eligible wnv - positive cases and 356 controls using a population proportionate to size model with us census bureau data .
we found that living near slow moving water sources was statistically associated with increased odds for human infection , while living near moderate moving water systems was associated with decreased odds for human infection .
living near bayous lined with vegetation as opposed to concrete also showed increased risk of infection .
the habitats of slow moving and vegetation lined water sources appear to favor the mosquito - human transmission cycle .
these methods can be used by resource - limited health entities to identify high - risk areas for arboviral disease surveillance and efficient mosquito management initiatives . |
despite the significant progress in the therapy of hematological malignancies there are several problems that impede the use of the polychemotherapy for treatment of this group of diseases .
the first one is the high intrinsic toxicity of multiple chemotherapies [ 1 , 2 ] that may lead to the multiple - organ failure in particular liver dysfunction .
the next is the strengthening of multidrug resistance ( mdr ) of tumor cells by cytostatic agents that are often characterized by the mdr phenotype even at baseline [ 35 ] .
these two problems can augment each other and can significantly reduce the efficiency of antineoplastic therapy .
the resistance of tumor cells to chemotherapy can be a result of various processes : from active atp - dependent transport of cytotoxic agents out of the cells executed by p - glycoprotein , the member of subfamily b of abc - transporters [ 6 , 7 ] , to disorders in the apoptosis , mutations or downregulation of p53 gene , impairing its proapoptotic function , and/or overexpression of bcl-2 gene causing insensitivity of cells to proapoptotic stimuli [ 810 ] .
studies of pharmacokinetics of antitumor drugs suggest that they undergo biotransformation in the liver with the formation of toxic metabolites , which may cause hepatocyte damage following hepatic dysfunction [ 11 , 12 ] .
hepatic dysfunction is one of the main factors limiting full adherence to the chemotherapy regimen by patients , because the development of complications in this organ due to chemotherapy can lead to lethal outcomes during cytostatic treatment .
although the researcher pays much attention to mdr phenotype acquiring by the tumor in the course of the treatment and separately to the influence of polychemotherapy onto the liver , little is known about the cumulative hepatotoxic effects evoked by cytostatics and by the tumor with mdr phenotype enhanced after exposure to multiple courses of chemotherapy . herein , we studied the combined toxic action of polychemotherapy by chop protocol , three components ( cyclophosphamide , doxorubicin , and vincristine ) of which are the substrates for abc - transporters and the impact of upregulated mdr of lymphosarcoma rls40 on the liver of experimental animals using two treatment schemes .
in the course of the treatment under scheme 1 the liver of tumor - bearing animals was subjected to the only one course of chop while tumor was consequently subjected to four courses of treatment .
it was achieved by the retransplantation of tumor cells from the animals received one course of chop , to the healthy animals with intact livers .
then the animals were subjected to the next course of chop while the tumor cells at the same time were exposed to the second course . as a result
four courses of polychemotherapy for the tumor were done but the liver has been exposed every time to the only one course .
this experimental model is artificial , because it has no analogue in patients in clinical practice .
we have developed this treatment scheme to evaluate the strengthening of the mdr of tumor and its contribution to the liver toxicity .
in the course of the treatment under scheme 2 tumor - bearing mice were exposed to three subsequent courses of chop .
this experimental model represents the real picture in clinical practice in cancer patients undergoing multiple courses of chemotherapy .
our data show that the toxic effect of polychemotherapy onto the liver is accelerated by the upregulated mdr of lymphosarcoma rls40 , and altogether they cause the increase in the destructive changes of the hepatocytes and the overall reduction in the regeneration capacity of the liver .
rls40 cell line was obtained from rls by selection of rls tumor cells in vitro in medium supplemented with vinblastine at concentrations ranged from 5 to 40 nm and displayed high resistance to a wide range of cytostatics .
rls40 cells were maintained in the iscove 's modified dulbecco 's medium ( imdm ) supplemented with 10% fetal bovine serum ( fbs ) and 1% antibiotic antimycotic solution ( 10.000 g / ml streptomycin , 10.000 iu / ml penicillin , and 25 g / ml amphotericin ; icn , germany ) in the presence of 40 nm vinblastine in a humidified atmosphere containing 5% co2 at 37c and were regularly passaged to maintain the exponential growth .
rls40 in ascitic form is permanent and maintained in cba mice by regular passaging of tumor cells . in order to generate ascites tumors from primary cell culture 2 10 cells / ml in 0.2 ml of the saline buffer
were intraperitoneally injected into the abdominal cavities of cba mice . for generating solid tumors from ascites intramuscular injections of 5 10 cells / ml in 0.1 ml of solution were performed into the right thigh muscle of cba mice .
the study was carried out on 1014-week - old male cba / lacsto ( hereinafter , cba ) mice bred at the institute of cytology and genetics ( siberian branch , russian academy of sciences , novosibirsk , russia ) .
the mice had free access to food and water and the daylight conditions were normal .
all animal procedures were carried out in accordance with approved protocol and recommendations for proper use and care of laboratory animals ( european communities council directive 86/609/cee ) .
solid tumors rls40 were induced via intramuscular injection of ascitic rls40 cells ( 5 10 cell / ml , 0.1 ml per mouse ) suspended in the saline buffer into the right thighs of mice . on day 7 after tumor transplantation
each mouse bearing rls40 was assigned to one of the two groups ( n = 15 per group ) : the first group , control , received the saline buffer intraperitoneally ; the second group received standard combination of cytostatics ( chop protocol ) .
the cytostatics were dissolved in the saline buffer directly before use and injected into the caudal vein in doses corresponding to 1/5 of ld50 : cyclophosphamide ( 50 mg / kg ) , doxorubicin ( 4 mg / kg ) , and vincristine ( 0.1 mg / kg ) ( lens - farm ) .
prednisolone ( 5 mg / kg ) ( nycomed ) was intraperitoneally injected daily for 5 days . on day 7 after chop ( day 14 after tumor transplantation ) at the 1st passage and on day 10 after chop ( day 17 after tumor transplantation ) at the subsequent passages , the mice were sacrificed by cervical dislocation under ether narcosis and tumor tissues were used for the preparation of cell suspension .
a portion of this suspension was used for the retransplantation ( passages ) into intact animals ( n = 30 ) ( 5 10 cell / ml ; 0.1 ml per mouse ) ; another portion was used for the preparation of primary cell culture and evaluation of gene expression profile . on day 7 after retransplantation of the tumor cells
a portion of mice were subjected to the 2nd course of chop ( n = 15 ) ; the control animals were left without treatment ( n = 15 ) . in total , four passages of tumors were carried out in mice followed by polychemotherapy .
material for gene expression analysis was collected on day 7 after chop at the first passage of the tumor and on day 10 after chop during the other passages of the tumor .
material for histological analysis was collected on days 1 , 3 , and 7 after the treatment at the first passage of the tumor , on days 7 and 10 at the second and the third passages , and on days 7 , 10 , and 14 at the fourth passage of the tumor .
1014-week - old male cba mice were assigned into 3 groups ( n = 45 per group ) . for generating of solid tumors
rls40 cells ( 10 cells / ml , 0.1 ml per mouse ) were transplanted intramuscularly into the right thighs of the animals of groups 1 and 2 .
after tumor transplantation group 2 ( tumor - bearing mice ) and group 3 ( mice without tumor ) received a standard combination of cytostatics ( chop protocol , see above ) .
group 1 ( rls40-bearing mice ) was left without treatment . on day 7 after chop ( day 14 after tumor transplantation ) ,
a portion of the mice were sacrificed by cervical dislocation under ether narcosis and tumor tissues were used for the preparation of primary cell culture .
the remaining mice both with the transplanted tumor and without the tumor received 2nd and 3rd courses of chop with an interval of 7 days . on day 7 after 2nd and 3rd courses of chop ( days 21 and 28 of tumor development ) mice were sacrificed .
material for histological study was collected on days 1 , 3 , and 7 after each course of chemotherapy .
material for gene expression analysis was collected on day 7 after each course of chemotherapy .
the tumor size was determined every other day using caliper measurements in three perpendicular dimensions .
tumor volumes were calculated as v = ( /6 length width height ) .
the inhibition of tumor growth was estimated as follows : [ ( mean tumor weightcontrol mean tumor weightexperiment)/mean tumor weightcontrol ] 100% .
isolation of primary cell culture from rls40 solid tumor was carried out by separation of cell suspension obtained after homogenization of solid tumors through lymphocyte separation medium ( lsm ) .
the cells were cultured in imdm supplemented with 10% fetal bovine serum ( fbs ) , 1% antibiotic antimycotic solution ( 10.000 g / ml streptomycin , 10.000 i.u./ml penicillin , and amphotericin 25 g / ml ; icn , germany ) at 37c and 5% co2 for 1 week until analysis .
rna concentration in the samples was measured by absorbance at 260 and 280 nm using a bio - mate 3 ( thermo electron corporation ) spectrophotometer .
the primers and rt - pcr conditions were described earlier [ 13 , 15 ] .
-actin - specific primers were added to the reaction mixture at the third and the first cycles , respectively .
bcl-2- and p53-specific products were amplified for 31 cycles ; -actin - specific primers were added to the reaction at the sixth cycle .
amplification was performed as follows : initial step 95c for 5 min , then 24 , 26 or 31 cycles of 94c for 1 min , 57c for 1 min , and 72c for 1 min .
pcr products were analyzed by electrophoresis in 8% polyacrylamide gel using tbe1 as running buffer , visualized by ethidium bromide staining , photographed in uv light , and densitometrically quantified using gel - pro analyzer 4.0 .
the data were presented as a ratio of specific gene expression level to -actin expression level .
the levels of tnf- , il-1 , il-6 , ifn- , and ifn- in the blood serum of mice bearing rls40 without any treatment and treated with two courses of chop were measured using mouse tnf - alpha , il-1-alpha , il-6 , and ifn - gamma colorimetric elisa kits ( thermoscientific , usa ) according to the manufacture 's protocols .
the level of ifn- was measured using mouse interferon alpha ( mu - ifn- ) elisa kit ( thermoscientific , usa ) . for morphological and morphometric analysis ,
tumor and liver samples of experimental animals were fixed in 10% neutral - buffered formaldehyde , routinely processed and embedded in paraffin [ 16 , 17 ] .
paraffin sections ( up to 5 m ) were stained with hematoxylin and eosin , microscopically examined and scanned .
stereological quantification was performed by point counting , using closed test system at a magnification 400 .
used test system has 16 straight - line segments and 25 testing points in a testing area equal to 1.16 10 m and was applied for microscopic examination and morphometric measurements [ 1820 ] .
morphometric analysis of the liver was performed and the volume densities ( vv ) of normal liver parenchyma , hepatic lymphoma infiltration , hepatocytes with degenerate , and necrotic changes ( destructive changes = degeneration + necrosis ) were evaluated . the volume density ( vv ) representing the volume fraction of tissue occupied by each compartment was determined from the points lying over these structures and calculated using the following formula : vv = ( pstructure / ptest ) 100% , where pstructure denotes the number of points over the structure and ptest represents the total number of test points , 25 in this case .
numerical density of binuclear hepatocytes ( nv ) indicating the number of cells in the unit of tissue volume was determined by counting the number of binuclear cells within the test area ( grid with a square of 1.16 10 m ) .
immunohistochemical staining of p - glycoprotein ( pgp ) ( ab 3364 , abcam , england ) in tumor and liver sections was carried out according to the manufacture 's protocol [ 21 , 22 ] .
index of pgp staining used for assessment of staining intensity of tumor sections was calculated as follows : in(pgp ) = ( number of pgp+ cells / total cell number ) 100% , where the total cell number was at least 100150 cells for each tumor sample [ 23 , 24 ] .
the intensity of pgp staining of the liver sections was scored on a scale of 03 + , in which 0 was no staining , 1 + weak positive staining , 2 + moderate positive staining , and 3 + strong positive staining .
the data were statistically processed using the student 's t - test ( two - tailed , unpaired ) ; p < 0.05 was considered statistically significant .
we used a tumor model with a proved predisposition to the strengthening of mdr status after cytostatic exposure - murine lymphosarcoma rls40 which is related to human diffuse large b - cell lymphoma .
rls40 was obtained by selection of rls tumor cells in vitro in medium supplemented with vinblastine at concentrations ranged from 5 to 40 nm and exhibits high resistance to a wide range of cytostatics .
parental rls tumor cell line is characterized by an increased expression of mdr1b and bcl-2 genes and decreased level of p53 gene .
rls40 tumor is resistant to apoptosis induction and is characterized by the upregulated mdr1a/1b genes ' expression .
the mdr of rls40 corresponds to the tumor status in patients after chemotherapy or to the status of a tumor initially resistant to standard chemotherapy protocols used as the first line therapy in the majority of hematological malignancies .
the aim of our study was to investigate the effect of polychemotherapy ( single and multiple ) onto aggravation of the liver toxicity and the impact of the enhanced mdr of tumor into observed hepatotoxicity .
for these purposes two experimental schemes were used ( figure 1 ) . in the treatment using scheme 1 mice with intramuscularly transplanted rls40 cells were exposed to polychemotherapy in chop regimen on day 7 after transplantation ( the 1st tumor passage ) . in 7 days
after the 1st course of chop tumor cells were retransplanted into healthy animals and the 2nd course of chop was done ( the 2nd tumor passage ) ( figure 1 , scheme 1 ) . in 10 days
after the 2nd course of chop tumor cells were retransplanted into healthy animals and the 3rd course of chop was done ( the 3rd tumor passage ) .
similarly the 4th tumor passage was carried out ( figure 1 , scheme 1 ) . rls40
undergone the same passages of retransplantation in the absence of chop was used as a control . this experimental model which is artificial as there is no counterpart in patients in clinical practice was developed to evaluate the impact of upregulated mdr of the tumor into hepatotoxicity in the absence of the damaging effect of multiple chemotherapies onto the liver . as the result of the treatment using scheme
1 tumor was subjected to several courses of chop ( from 1 to 4 , in total 4 ) , the liver was subjected to only one chop exposure . during the treatment using scheme 2 a group of mice with intramuscularly transplanted rls40 cells was exposed to three subsequent courses of polychemotherapy in chop regimen ( figure 1 , scheme 2 ) . on day 7 after tumor transplantation mice were exposed to chop ( the 1st course ) ; the 2nd and the 3rd courses were done with the interval of 7 days .
a group of mice with rls40 without exposure to chop and a group of mice without tumor but exposed to chop were used as controls .
this experimental model represents the real picture in clinical practice in patients undergoing multiple chemotherapies and allows us to study the effect of both multiple courses of polychemotherapy and deepening mdr of tumor onto hepatotoxicity .
levels of expression of the genes involved in the formation of multidrug resistance were estimated to confirm the enhancement of mdr of tumor after multiple chemotherapies . as expected after the treatment both at scheme 1 and scheme 2 the increase in expression of these genes was observed . at baseline rls40 cells
were characterized by high expression levels of mdr1a , mdr1b , and p53 genes and low expression level of bcl-2 gene ( figure 2 ) that correlated with the data obtained earlier [ 13 , 15 ] .
the treatment under scheme 1 resulted in 1.3- and 2.2-fold increases of the expression levels of mdr1b and bcl-2 genes , respectively , ( figure 2(a ) , right panel , and figure 2(c ) , left panel ) .
the treatment under the scheme 2 caused 2.8- and 2-fold increases of the expression of these genes , respectively , ( figure 2(b ) , right panel , and figure 2(d ) , left panel ) .
however , the treatment under scheme 1 and scheme 2 differently affected the expression level of p53 gene ( figures 2(c ) and 2(d ) , right panels ) . after the treatment under scheme 1 after two and four courses of polychemotherapy the expression levels of p53 gene in rls40 cells increased 1.2- and 1.6-fold , respectively , in comparison with the baseline . after the treatment under scheme 2 after the 1st and the 2nd courses a 4.4-fold drop of the expression level of p53 gene was seen in comparison with the baseline , but after the 3rd course gene expression it was slightly increased again .
neither the treatment under scheme 1 nor the treatment under scheme 2 has an effect on the expression level of mdr1a gene ( figures 2(a ) and 2(b ) , left panels ) , which was in consistent with earlier data that this gene poorly responded to the treatment [ 13 , 15 ] .
alteration in the expression of mdr1b , bcl-2 , and p53 genes after the treatment that has been observed both at the artificial experimental conditions and at real - life
situation of mdr status enhanced due to multiple chemotherapies in hematological patients which indicates not only the strengthening of mdr , but also abnormalities of the apoptosis mechanism [ 2628 ] . as the p - glycoprotein level on the surface membrane of tumor cells displays mdr of tumor [ 2931 ] we estimated pgp representation on the surface of the tumor before and after the treatment .
it is seen that about 30% of rls40 cells were initially pgp positive ( pgp+ ) ( figure 3(a ) ) . as expected multiple chemotherapies resulted in the significant increase in pgp level on the membrane of tumor cells .
the treatment under scheme 1 caused the significant increase in the number of pgp+ cells in tumor : from 30% at baseline to 55.5 1.5% after the 1st course and to 88.2 1.5% after the 4th course of chop ( figure 3(b ) ) .
the treatment under scheme 2 also resulted in the increase in pgp level on the membrane of tumor cell : after the 1st and the 2nd courses of chop the number of pgp+ cells was similar ( 60.9 0.5% and 63.3 0.5% , resp . ) , but after the 3rd the number of pgp+ cells significantly increased up to 85.9 1% .
dynamics of tumor growth in mice exposed to the chop treatment according to scheme 1 and scheme 2 were approximately the same regardless of the treatment regimen ( figure 4 ) .
reliable inhibition of rls40 tumor growth occurred upon the treatment both with scheme 1 and scheme 2 , though rls40 is not entirely regressed ( figures 4(a ) and 4(b ) ) .
the inhibition of tumor growth depends on the number of treatment courses : after the 1st course of chop at scheme 1 the inhibition of tumor growth was 36.6% , after the 2nd 58.7% ( figure 4(a ) ) .
the 3rd and the 4th courses of chop did not result in more pronounced inhibition of tumor growth : the inhibition rates were 50.5% and 45.5% , respectively , ( figure 4(a ) ) .
after the treatment under scheme 2 , reasonably similar effects were observed independent of the number of chop courses and the inhibition of tumor growth was approximately 50% .
( figure 4(b ) ) . in the serum of mice bearing rls40 without any treatment
the increase in ifn- ( up to 200 pg / ml ) and il-6 ( up to 460 pg / ml ) in comparison with healthy animals was observed .
two courses of chop treatment resulted in a strong activation of inflammatory response that should be considered as a negative event and an increase of interferons was regarded as a positive immunomodulatory activity .
we observed statistically significant 8-fold increase in il-1 ( up to 240 pg / ml ) , 2-fold increase in il-6 ( up to 830 pg / ml ) , 20-fold increase in tnf- ( up to 110 pg / ml ) , 7.5-fold increase in inf- ( up to 1500 pg / ml ) , and 9-fold increase in inf- ( up to 90 pg / ml ) .
several factors can contribute to hepatotoxicity including endogenous intoxication caused by primary tumor node , metastatic infiltration of the liver , polychemotherapy itself and induced cytokine storm , and enhanced mdr of tumor . since the basic idea of our work was the assumption that the upregulation of mdr of the tumor negatively affects the liver , we evaluated morphological changes and regeneration capacity of the liver depending on the number of the polychemotherapy courses affected the liver and the enhancement of mdr of the tumor .
diffuse and focal infiltration of the liver by tumor cells was detected in tumor - bearing mice both without any treatment and subjected to the cytostatic treatment independently from the experimental scheme .
volume density of metastasis in the liver on day 17 after tumor transplantation reached 21 4% in the control group and 18 3% after the treatment under scheme 1 but this difference was statistically insignificant . in the case of scheme 2 hepatic lymphoma infiltration
progressively increased and reached up to 30 5% of the entire liver parenchyma to day 24 after tumor transplantation both in groups after treatment and without it .
upon the development of rls40 without any treatment metastatic infiltration of the liver by tumor cells was accompanied with severe destructive changes increased with tumor progression : from 19 0.9% ( on day 8 after transplantation ) to 54.2 1.3% ( on day 21 after transplantation ) . at the initial phase of tumor development alterative changes in the liver tissue were predominantly presented by degeneration of hepatocytes ( 11.4 0.7% degeneration , 7.6 0.7% necrosis ) . at a later date
necrotic changes of the liver parenchyma were predominated ( 19.8 1% degeneration , 34.4 1.3% necrosis ) .
the numerical density of binuclear hepatocyte decreased 1.5-fold ( from 0.85 0.15 to 0.55 0.1 ) , that shows a decline in the regeneration of liver tissue during tumor progression . in the early stage of tumor progression ( day 8 after transplantation ) in the group of animals with rls40
subjected to chop treatment a lesser pronounced infiltration of the liver parenchyma by tumor cells was identified , than in the control group ( tumor - bearing animals without treatment ) .
however , the volume density of destructive changes increased 1.5-fold in comparison with the control ( 28.8 1% versus 19 0.9% on day 8 after transplantation ) . at the latter stage of tumor progression ( day 21 after tumor transplantation ) in the same group of animals
the volume density of alterative changes represented mainly by necrosis of the liver parenchyma continued to increase , but in a lesser extent in comparison with the control ( tumor - bearing mice without any treatment ; 51.2 0.8% versus 54.2
the numerical density of binuclear hepatocytes changed insignificantly ( from 0.7 0.2 to 0.5 0.1 ) .
comparison of the morphological changes developed in the liver to one and the same date at sequential passages of the tumor cells according to the scheme 1 without treatment revealed a 1.8-fold increase in necrosis in the liver parenchyma after the 4th passage in comparison with the 1st passage of the tumor without treatment , while the level of degeneration in the liver parenchyma remained unchanged ( table 1 ) .
the numerical density of binuclear hepatocyte decreased 2-fold ( from 1 0.2 to 0.5 0.1 ) after the 4th passage in comparison with the 1st passage .
comparison of the morphological changes developed in the liver to one and the same day after tumor transplantation and chop treatment at sequential passages of the tumor cells according to the scheme 1 revealed changes in the proportion of destructive changes in the liver of experimental animals from one passage to another .
after the 1st passage ( one course of chop for the tumor and one for the liver ) the percentage of degenerative and necrotic cells was similar .
while after the 4th passage ( four courses of chop for the tumor and only one for the liver ) the volume density of necrotic changes in the liver increased 1.3-fold and the volume density of degenerative change decreased 1.4-fold in comparison with the 1st passage of the tumor , which attests to the possible transformation of degeneration into necrosis ( table 1 ) .
the numerical density of binuclear hepatocytes decreased 1.8-fold after the 4th passage in comparison with the 1st one ( from 0.9 0.1 to 0.5 0.1 ) .
after three sequential courses of chop treatment ( scheme 2 ) both in animals with transplanted tumors and without tumors severe destructive changes in the liver parenchyma were revealed , but the dynamics of these changes in experimental groups were quite different . on day 1
after the 1st course of chop in healthy mice the volume density of destructive changes in liver parenchyma consisting predominantly of degenerative hepatocytes was 50.8 2.3% ; on day 3 and day 7 these values decreased 1.3- and 1.8-fold , respectively , ( table 2 ) . on day 1 and day 3 both after the 2nd and the 3rd courses of chop the percentage of destructive changes in liver parenchyma did not differ significantly from the value after the 1st course of chop ; however , on day 7 both after the 2nd and the 3rd courses of chop these values increased 1.7- and 1.8-fold , respectively , as compared to the 1st course of chop administered to healthy mice ( table 2 ) . on day 1 and day 3 after the 1st course of chop under scheme 2 in mice with rls40 volume densities of destructive changes in liver parenchyma were 53.8 3% and 39.8 2% , respectively .
these changes were presented predominantly by degenerative hepatocytes and did not differ significantly from healthy mice exposed to chemotherapy at the same regimen . on day 7
after the 1st course of chop in tumor - bearing mice the percentage of destructive changes in liver parenchyma increased 1.6-fold in comparison with the healthy mice exposed to the same treatment .
after remaining courses of chop destructive changes in liver tissue of tumor - bearing mice continued to increase progressively and as a result amounted to 85% of liver parenchyma ( table 2 ) . to evaluate the toxic effect of multiple chemotherapies and tumor with advanced mdr on the regeneration capacity of the liver the numerical density of binuclear hepatocytes
was measured in the groups of experimental animals subjected to the treatment under scheme 2 with or without tumor ( figure 5 ) .
maximal number of binuclear hepatocytes is observed on 1 - 2 days after any damage ( alcohol , chemotherapy , ccl4 , lps ) .
hepatocyte degeneration can turn into either necrosis or regenerate and become normal hepatocytes due to the potential of binuclear hepatocytes . for all groups of animals
the bell - shaped kinetics of numerical density of binuclear hepatocytes was observed : no effect on day 1 , the maximal regeneration burst was observed on day 3 , and decrease in numerical density was observed on day 7 after polychemotherapy . in the group of healthy animals
subjected to polychemotherapy the regeneration capacity did not depend on the number of chop courses ( 1.55 0.3 , 1.6 0.2 , and 1.9 0.2 at the day 3 after the 1st , the 2nd , and the 3rd courses of chop , resp . ) . however , in the group of animals bearing rls40 each subsequent course of chop resulted in the progressive decrease in regeneration capacity of the liver : the numerical density of binuclear hepatocytes was 1.6 0.3 , 1.2 0.2 , and 0.7 0.15 at the day 3 after the 1st , the 2nd , and the 3rd courses of chemotherapy ( figure 5 ) .
volume density of metastasis in the liver reached 30% at the end of the experiment and also contributed to the drop of regeneration capacity of the liver . during the rls40 passaging without treatment ( scheme 1 , control group ) the numerical density of binuclear hepatocytes did not change between the passages and was 1 0.15 ( day 14 after tumor transplantation ) . during the rls40 passaging with polychemotherapy ( scheme 1 , experimental group )
the numerical density of binuclear hepatocytes also did not change between the passages and was 0.8 0.1 ( day 14 after tumor transplantation , day 7 after treatment ) .
the obtained data point to combined ( synergic ) toxic effects of the endogenous intoxication caused by primary tumor node , metastatic infiltration of the liver , multiple chemotherapies , and upregulated mdr of the tumor onto the liver that results in the significant destructive changes in the liver tissue and substantial reduction of the regenerative capacity of the liver .
it was shown that the liver tissue of healthy mice without any treatment is characterized by pgp expression : the percentage of hepatocytes with pgp 2 + and pgp 3 + was about 40% of the entire population of liver cells .
after three subsequent courses of chop ( scheme 2 ) in healthy mice the increase in pgp expression on hepatocyte membrane was detected : after the 1st course of chop the total percentage of hepatocytes with pgp 2 + and pgp 3 + was 55.8 0.5% , after the 2nd course 58.3 0.5% , and after the 3rd course 63 0.7% . therefore , several courses of chemotherapy in healthy mice resulted in a gradual and slow increase in pgp expression in the liver tissue .
in contrast to healthy mice three courses of chop in tumor - bearing mice ( scheme 2 ) caused a rapid and more pronounced increase in pgp expression : after each course of chop the percentage of hepatocytes with pgp 2 + and pgp 3 + was about 70% of the entire population of liver cells . after the treatment of tumor - bearing animals under scheme 1 ( four courses of chop for the tumor and only one for the liver ) the increase in hepatocyte percentage with pgp 2 + and pgp 3 + was also detected .
after the 1st tumor passage with the following cytostatic treatment percentage of hepatocyte with pgp 2 + and pgp 3 + was 57.8 0.45% , after the 2nd 59.8 0.5% , after the 3rd 63.3 0.5% , and after the 4th 64.9 0.3% ( figure 6 ) .
therefore , despite the fact that the liver is exposed to only one course of chemotherapy , the upregulation of mdr of the tumor makes a contribution to the increase in pgp expression in the liver tissue after cytostatic influence .
progress in antitumor therapy of hematological malignances achieved over the past decades resulted in an increase in the amount of complete remission , progression - free survival , and recovery in some cases .
these results are due to the use of effective chemotherapy protocols based on the decrease in intervals between chemotherapy courses , increase in cytostatic dose , and introduction of additional chemotherapeutic agents into the protocol .
however , the high toxicity of multiple courses of chemotherapy and multidrug resistance of tumor cells usually typical for hematological malignancies even at the baseline are important obstacles significantly reducing the efficiency of the treatment . the potential of antitumor chemotherapy is often limited by hepatotoxicity of cytotoxic drugs undergoing biotransformation in the liver [ 11 , 12 ] .
the risk of toxic complications due to high concentrations of cytostatic metabolites is increased by tumor intoxication and metastatic lesion of the liver .
toxic damage of the liver impedes the long - term treatment , reduces the efficiency of cytostatic therapy , and requires constant correction by the hepatotropic drugs in the intervals between the treatment courses .
a number of factors may contribute to the toxic effects of chemotherapy ( genetically predisposed individual features of drug metabolism , the presence of comorbidity , and other factors affecting the detoxication function of the liver ) [ 36 , 37 ] .
p - glycoprotein - mediated multidrug resistance of tumor may be one of these factors due to the increasing burden of cytostatics onto the liver through the drug pumping out of tumor cells .
herein , we studied the combined effect of polychemotherapy ( chop protocol ) and lymphosarcoma rls40 characterized by enhanced mdr onto the liver of experimental animals using two treatment schemes .
scheme 1 is an artificial and has no analogues in clinical practice . according to scheme
1 four courses of chop for tumor were completed , but only one was applied for the liver .
scheme 2 reflects a real - life situation , where tumor - bearing mice were exposed to three subsequent courses of chop , so both the liver and the tumor have three chop courses . in the case of rls40 tumor model
several factors can contribute to hepatotoxicity : endogenous intoxication caused by primary tumor node , metastatic infiltration of the liver , polychemotherapy itself and induced cytokine storm , and enhanced mdr of the tumor .
we attempted to evaluate the contribution of the multiple chemotherapies and the strengthened mdr of the tumor to hepatotoxicity as well as the combined effect of the multiple chemotherapies and the tumor with upregulated mdr on the liver . as it was expected the enhancement of mdr of the tumor at the treatment under scheme 1 and scheme 2
multiple chemotherapies cause an additional increase in mdr1b and bcl-2 gene expression in rls40 cells that makes the tumor less sensitive to cytostatic treatment [ 27 , 38 ] .
we also confirmed that multiple chemotherapies in different regimens caused the significant increase in pgp expressions on the membrane of tumor cells up to 90% of the entire tumor tissue .
we evaluated the destructive changes and regeneration capacity of the liver that reflect the degree of hepatic dysfunction .
morphological analysis of the liver of tumor - bearing mice both without treatment and after chop treatment revealed its diffuse and focal infiltration by tumor cells , which by itself is a liver damaging factor . at the time of tumor development without any treatment infiltration of liver tissue by tumor cells was accompanied by severe destructive changes due to both the tumor invasion and to mediated influence of the growing tumor on the host by endogenous intoxication .
the livers of mice with rls40 subjected to chop are characterized by an increase in the total destructive changes , occupying more than 80% of liver parenchyma , in comparison with healthy animals without tumors subjected to chop treatment and tumor - bearing animals without any treatment .
differences in the destructive changes in the liver confirm that multiple chemotherapies and tumor with upregulated mdr have a synergistic damaging effect on the liver .
one of the most important characteristics of the liver is its regeneration capacity , the morphological expression of which is the numerical density of binuclear hepatocytes .
chemotherapy in the absence of tumor virtually does not affect the numerical density of binuclear hepatocytes after triple exposure ( scheme 2 ) , which points to the maintenance of regeneration capacity of the liver .
but the strengthening of mdr of rls40 after each subsequent course of chemotherapy ( scheme 2 ) together with metastasis progression reduces the numerical density of binuclear hepatocytes and impairs the liver regeneration capacity .
treatment under scheme 1 also leads to the decrease in the regeneration capacity of the liver , but less significantly . together with the pressure of multiple chop , hepatic lymphoma infiltration and
the enhancement of mdr of the tumor one of the reasons for decline of the regeneration capacity of the liver may be the synergic rising of toxic burden .
it takes place because of the strengthening of multidrug resistance of the tumor that considering the large tumor mass relative to body weight leads to increased concentrations of cytostatics due to their force pumping out of tumor cells .
components of chop treatment are released into the bloodstream and as a result the liver does not handle the metabolic burden .
although the level of pgp in the liver increases it is not sufficient to protect hepatocytes which is confirmed by an increase in destructive changes .
additionally the increase in necrotizing sites within the tumor also contributes into the toxic burden on the liver .
therefore , hepatotoxic effects may become stronger with the progression of mdr of the tumor .
the liver tissue itself has rich system of membrane transporters , proteins involved in the absorption , metabolism , distribution , and excretion of xenobiotics [ 40 , 41 ] , providing the maintenance and restoration of its own liver structure and this function is partly mediated by pgp [ 4244 ] .
a number of chemicals , including cytotoxic drugs used in multiple dosing regimens , may cause an alteration in p - glycoprotein expression in different tissues ( liver , kidney , and intestine ) and lead to a change in drug pharmacokinetics [ 4547 ] . in our study
we showed that exposure of healthy animals to chop in full regimen ( under scheme 2 , three courses ) caused a slow and gradual increase in p - glycoprotein expression on the membrane of hepatocytes . at the same time exposure of animals with rls40 to chop under scheme 2 irrespective of
our data also revealed a small but reliable increase in pgp expression in the liver tissue of animals having one chop course onto the liver and four chop courses onto the tumor ( scheme 1 ) in comparison with animals having one chop course onto the liver and one chop course onto the tumor .
such alteration in the expression of transporter proteins may represent a compensatory mechanism after the toxic effect of the chemotherapy onto the liver enhanced by the upregulated mdr of the tumor .
the increase of the concentration of transporters in the membrane of hepatocytes may reduce the accumulation of potentially toxic chemicals [ 4951 ] .
but in the used experimental models it was not sufficient to protect hepatocytes from further damage , what we observed as an increase in destructive changes .
our data suggest that mdr status of a tumor may be one of the damaging factors , which contributes to toxic liver burden during polychemotherapy .
progression of multidrug resistance of the tumor negatively affected the liver of the host and caused strong hepatotoxic effects manifested by the accumulation of degenerative changes of hepatocytes and the reduction in regeneration capacity of the liver .
these data suggest that mdr status of the tumor at baseline may contribute to toxic liver burden and serve as a negative predictor parameter of hepatic dysfunction .
the toxic effects of multiple chemotherapies onto the liver are accelerated by strengthening mdr of the tumor that should be taken into account when developing therapeutic regimens of malignancies with upregulated mdr . in this context , it is relevant to develop approaches for overcoming or reducing unfavorable toxic effects caused by polychemotherapy in combination with the upregulated mdr of the tumor .
this can be achieved through the development of individual treatment protocols with detection of mdr status of the tumor prior to therapy and overcoming mdr using modern molecular gene - targeted approaches . | antitumor therapy of hematological malignancies is impeded due to the high toxicity of polychemotherapy toward liver and increasing multiple drug resistance ( mdr ) of tumor cells under the pressure of polychemotherapy .
these two problems can augment each other and significantly reduce the efficiency of antineoplastic therapy .
we studied the combined effect of polychemotherapy and upregulated mdr of lymphosarcoma rls40 onto the liver of experimental mice using two treatment schemes .
scheme 1 is artificial : the tumor was subjected to four courses of polychemotherapy while the liver of the tumor - bearing mice was exposed to only one .
this was achieved by threefold tumor retransplantation taken from animals subjected to chemotherapy into intact animals .
scheme 2 displays real - life status of patients with mdr malignancies : both the tumor and the liver of tumor - bearing mice were subjected to three sequential courses of polychemotherapy .
our data show that the strengthening of mdr phenotype of rls40 under polychemotherapy and toxic pressure of polychemotherapy itself has a synergistic damaging effect on the liver that is expressed in the accumulation of destructive changes in the liver tissue , the reduction of the regeneration capacity of the liver , and increasing of pgp expression on the surface of hepatocytes . |
pulmonary arterial hypertension ( pah ) is a rare incapacitating disease with progressive functional limitation and deterioration to right heart failure and death .
in addition to various disorders that can cause pah , a genetic predisposition to this disease was identified with the discovery of mutations in the gene encoding the bone morphogenetic protein receptor type 2 ( bmpr2 ) , a member of the transforming growth factor- ( tgf- ) receptor , in both the familial and the sporadic cases of pah [ 13 ] .
heritable pah ( hpah ) segregates as an autosomal - dominant disorder with variable age of onset , reduced penetrance , approximately a 2:1 female : male ratio , and genetic anticipation in some pedigrees [ 46 ] .
approximately 6% of the individuals diagnosed with pah have a family history of this disorder .
bmpr2 mutations are heterogeneous , with missense , nonsense , frameshift , splice site , and both small and large gene deletions and duplications found throughout the gene [ 7 , 8 ] .
disease - causing mutations have been identified in approximately 70% of hpah and 526% of idiopathic pah ( ipah ) patients [ 811 ] .
we present a novel bmpr2 mutation - associated case of pah first diagnosed at 83 years of age . to the best of our knowledge
an 83-year - old world war ii veteran presented for evaluation of fatigue and breathlessness with exertion at new york heart association iii functional class with findings of elevated right - sided pressures on echocardiogram .
he gave a history of progressive dyspnea with physical activity for 4 years and pedal edema for 6 months which was symmetrical and worse during the evenings .
his past medical history included mild hypertension , nocturnal hypoxemia requiring oxygen therapy , gout , and degenerative arthritis of his right knee from shrapnel injury during world war ii .
he had an episode of syncope approximately 1 year prior to evaluation that was attributed to dehydration and heat exhaustion .
echocardiogram done at that time had shown preserved left ventricular ejection fraction at 70% , enlarged right - sided chambers , and estimated right ventricular systolic pressures of 80 mmhg .
he had no history of thromboembolic disease , chronic lung disease , or prior transfusions .
he recalled his mother ( nonsmoker ) was diagnosed with pulmonary hypertension ( ph ) and emphysema and had died at age 65 .
his brother and a maternal first cousin had died with a diagnosis of ph at age 49 and 71 , respectively .
the patient remembered that ph was identified on echocardiograms in his affected relatives but did not recollect details of other diagnostic workup .
one of his brothers died of cirrhosis while his youngest brother was alive and had a history of coronary artery disease .
his blood pressure was 92/61 mmhg , heart rate was 105/min , respiratory rate was 1820/min , oxygen saturation was 92% on room air , and body mass index was 26.6 kg / m .
abnormal findings on examination included accentuated pulmonic component of second heart sound , 3/6 pansystolic murmur at the left lower sternal border , and bilateral pitting pedal edema .
abnormal laboratory parameters included a brain natriuretic peptide of 335 pg / ml , serum creatinine of 1.4 mg / dl , and hemoglobin of 18 g / dl .
chest x - ray showed cardiomegaly , prominent pulmonary vasculature , and normal lung fields .
electrocardiogram showed right axis deviation , right ventricular hypertrophy , and inverted t waves in v1-v4 .
echocardiogram was repeated and showed marked dilatation of right atrium and ventricle , impaired systolic right ventricular function , moderate to severe tricuspid regurgitation , and estimated peak pulmonary artery pressures of 100 mmhg with left ventricular ejection fraction of 55% without segmental wall motion abnormalities or pericardial effusion .
a 6-min walk test was severely impaired with a total distance of 67.06 m or 30.9% of the predicted lower limit of normal calculated to be 216.8 m for his age and body mass index using the enright and sherrill formula .
collagen vascular workup and hepatitis screen were negative , and hiv testing was not done as he denied risk factors .
right heart catheterization confirmed pulmonary arterial hypertension with pulmonary artery pressures of 102/44 mmhg ( mean = 63 mmhg ) , mean pulmonary artery occlusive pressure of 9 mmhg , mean right atrial pressure of 19 mmhg , mixed venous saturation of 61.5% , thermodilution cardiac output of 2.72 l / min , and cardiac index and pulmonary vascular resistance calculated at 1.48 l / min / m and 1588 dyn s / cm , respectively .
acute vasodilator study with inhaled nitric oxide did not show vasoreactivity . with a family history of relatives carrying a diagnosis of ph , genetic testing
using previously described techniques , bmpr2 dna and rna mutation screening was performed upon peripheral lymphocytes and identified mutation c.241inst in exon 2 of the bmpr2 gene ( fig . 1 ) .
this disease - causing mutation in codon 81 replaced lysine with a stop codon.fig .
1sequencing results demonstrating mutation c.241inst in dna and mrna sequencing results demonstrating mutation c.241inst in dna and mrna amlodipine was stopped and he was started on digoxin , warfarin , and bosentan , which was titrated to a target dose of 125 mg two times a day . at the time of his last office visit and after a year of bosentan therapy , he reported better tolerance for physical activity with improvement in functional class to nyha ii .
his 6-min walk distance had improved to 146.3 m ( 67.5% of predicted lower limit of normal ) and was mainly limited by knee pain .
follow - up right heart catheterization showed a right atrial mean pressure of 3 mmhg , pulmonary artery pressure of 95/20 mmhg ( mean = 45 mmhg ) , pulmonary capillary wedge pressure of 6 mmhg , cardiac output of 2.9 l / min , and calculated cardiac index and pulmonary vascular resistance of 1.6 l / min / m and 1075 dyn s / cm , respectively .
we describe the case of an 83-year - old man presenting with pulmonary arterial hypertension due to a previously unreported bmpr2 mutation c.241inst .
this dna single base insertion at codon 81 results in a frameshift with a stop codon at this site causing premature truncation of the bmpr2 protein .
this mutation creates messenger ribonucleic acid ( mrna ) that would be identified and subjected to nonsense - mediated decay ( nmd ) .
interestingly , a low level of aberrant mrna was detected in the lymphocytes from this patient ( fig . 1 ) .
recently , sztrymf et al . reported that pah carriers of bmpr2 mutations presented 10 years earlier than ipah patients ( 36.5 14.5 vs. 46.0 16.1 ) . carriers of bmpr2-truncating mutations ( nmd positive ) have a later age of diagnosis and death than carriers of a bmpr2 missense mutation ( nmd negative ) .
this recent study of nmd - associated bmpr2 mutations provides additional evidence of the protective function of nmd in heterozygote carriers of dominant disorders . since only 1020% of individuals with a bmpr2 mutation
develop pah , it is suggested that both environmental factors and modifier genes explain the reduced penetrance of hpah [ 1721 ] .
single nucleotide polymorphisms in the tgf1 gene and variations in genes associated with proliferation , gtp signaling , stress response , and estrogen metabolism have been proposed to modulate the age of diagnosis and penetrance in these families [ 18 , 19 ] .
recently , expression of wild - type allele bmpr2 transcripts has been reported as being important in determining penetrance of hpah .
thus , the late age of onset in our patient can be likely explained by a nmd - positive bmpr2 mutation and the presence of modifier genes and/or unknown environmental factors which conveyed protection from pah at an earlier age .
it is interesting that the mutant bmpr2 mrna was detected at a low level in the lymphocytes of the patient and apparently escaped complete nmd in this tissue .
the status of the mutant bmpr2 mrna in the lung of the patient is unknown .
however , if the mutant bmpr2 mrna also escaped complete degradation by nmd in the lung tissue of our patient , it is then presumed that the severely truncated mutant protein was unable to interfere effectively with the function of the wild - type bmpr2 protein in a dominant - negative manner .
thus , one would predict that this patient probably developed pah through haploinsufficiency of the bmpr2 protein .
clinical testing for bmpr2 mutations is appropriate care for the management of patients with a family history of pah regardless of the age at presentation as detection of family - specific mutations can be used to counsel family members at risk for developing pah .
identification and analysis of different mutations will help understand the disease at a genetic level and explore treatment options that can be offered to patients and their families with hpah .
prior to proceeding with presymptomatic genetic testing , counseling to discuss the complexity of this disease and the reduced risk for developing the disease in the presence of the mutation is required . | we describe the case of an 83-year - old man with a family history of pulmonary hypertension ( ph ) who presented with severe pulmonary arterial hypertension ( pah ) and later tested positive for a novel bone morphogenetic protein receptor 2 ( bmpr2 ) gene mutation . to our knowledge
, this may be the oldest reported patient with pah in whom a bmpr2 mutation was initially identified . |
with the rapid progress in miniaturization of the solid - state devices , the effect of carriers spin in semiconductor has attracted considerable attention for its potential applications in photoelectric devices and quantum computing .
the traditional standard method of spin control depends on the spin injection technique , with mainly relies on optical techniques and the usage of a magnetic field or ferromagnetic material . due to its unsatisfactory efficiency in nano - scale structures , generating and controlling a spin - polarized current with all - electrical means in mesoscopic structures
but if a device is formed in a semiconductor two - dimensional electron gas system with an asymmetrical - interface electric field , rashba spin orbit interaction ( rsoi ) will occur .
the rsoi is a relativistic effect at the low - speed limit and is essentially the influence of an external field on a moving spin .
it can couple the spin degree of freedom to its orbital motion , thus making it possible to control the electron spin in a nonmagnetic way .
many recent experimental and theoretical works indicate that the spin - polarization based on the rsoi can reach as high as 100% or infinite [ 11 - 13 ] , and then attracted a lot of interest .
recently , an aharnov - bohm ( ab ) ring device , in which one or two quantum dots ( qds ) having rsoi are located in its arms , is proposed to realize the spin - polarized transport .
the qds is a zero - dimensional device where various interactions exist and is widely investigated in recent years for its tunable size , shape , quantized energy levels , and carrier number [ 14 - 16 ] .
a qds ring has already been realized in experiments and was used to investigate many important transport phenomena , such as the fano and the kondo effects . when the rsoi in the qds is taken into consideration
, the electrons flowing through different arms of the ab ring will acquire a spin - dependent phase factor in the tunnel - coupling strengths and results in different quantum interference effect for the spin - up and spin - down electrons . in this article , we focus our attention on the 100% spin - polarized transport effect in a double qds ring . as shown in fig .
1 , the two qds embedded in each arms of the ring are coupled to the left and the right leads in a coupling configuration transiting from serial ( = 0 ) to symmetrical parallel ( > 0 ) geometry .
we assume that the rsoi exists only in the qds and the arms of the ring and the leads are free from this interaction .
furthermore , the two dots are assumed to couple to each other by a spin - polarized coupling strength where tc is the usual tunnel coupling strength , t may arises from a constant magnetic field applied on the junction between the qds , and the phase factor r is induced by the rsoi in the qds .
system of a double qds ring connected to the left and the right leads with different coupling strengths
the second - quantized form of the hamiltonian that describes the double - dot interferometer can be written as ( 1 ) where is the creation ( annihilation ) operator of an electron with momentum k , spin index or 1 , and and energy k in the th ( = lr ) lead ; creates ( annihilates ) an electron in dot i with spin and energy i;ui is the coulomb repulsion energy in dot i with being the particle number operator , in the following we set u1 = u2 = u for simplicity ; t describes the dot dot tunneling coupling and the matrix elements ti are assumed to be independent of k for the sake of simplicity and take the forms of and the phase factor ri arises from the rsoi in dot i , which is tunable in experiments .
in fact , the rsoi will also induce a inter - dot spin - flip , which has little impact on the current and is neglected here .
the spin - dependent tunnel - coupling strength ( line - width function ) between the dots and the leads is defined as ij = 2ktitj(k ) , ( = lr ) . according to fig .
1 , the matrix form of them read ( here we set tl1 = tr2 = t and tr1 = tl2 = t)(2)(3 ) where the spin - dependent phase factor = r , with r = r1r2 , this indicates that the tunnel - coupling strength only depends on the difference between r1 and r2 , and then one can assume that only one qd contains the rsoi , making the structure simpler and more favorable in experiments .
the phase - independent tunnel - coupling strength is = + , with = 2|t| , and is the density of states in the leads ( the energy - dependence of is neglected )
. the general current formula for each spin component through a mesoscopic region between two noninteracting leads can be derived as ( 4 ) where is the fermi distribution function for lead with chemical potential . the 2 2 matrices and g( ) are , respectively , the lesser and the retarded ( advanced ) green s function in the fourier space .
we employ the equation of motion technique to calculate both the retarded and the lesser green s functions by adopting the hartree - fock truncation approximation , and arrive at the dayson equation form for the retarded one : ( 5 ) where the retarded self - energy the diagonal matrix elements of green s function g( ) for the isolated dqd are(6 ) and the off - diagonal matrix elements are tc .
the advanced green s function g( ) is the hermitian conjugate of g( ) . the occupation number < ni > in eq .
6 needs to be calculated self - consistently ; its self - consistent equation is within the same truncating approximation as that of the retarded green s function , the expression of can be simply written in the keldysh form the matrix elements of the lesser self - energy are in general and thus eq . 6 of the current is reduced to the landauer - bttiker formula for the non - interacting electrons ( 7 ) and then the total transmission t( ) for each spin component can be expressed as the linear conductance g( ) is related to the transmission t( ) by the landauer formula at zero temperature , g( ) = ( e / h)t( ) .
in the following numerical calculations , we set the temperaturet = 0 throughout the article .
the local density of states in the leads is chosen to be 1 andt = 0.4 so that the corresponding linewidth is set to be the energy unit .
figure 2a c shows the dependence of the conductance g and spin polarization on the fermi level for = u = 0 and various t .
the two dots now are connected in a serial configuration and the conductance of each spin component is composed of two breit - wigner resonances peaked at respectively . since the phase factors originating from both the magnetic flux and the rsoi do not play any role , the device is free from their influences .
when t = 0 , the spin - up and spin - down conductances are the same and the spin polarization p = 0 as shown by the solid lines in the three figures . with increasing t ,
the distance between the spin - up resonances is enhanced whereas that between the spin - down ones is shrunk because of as shown in fig .
if t is set to be t = tc , the spin - up and spin - down inter - dot tunneling coupling strengths are and respectively .
then the spin - up conductance has a finite value but meanwhile as the conduction channel for the spin - down electrons breaks off , which is shown by the dot - dashed lines in fig .
2a , b. the spin orientation of the non - zero conductance can be readily reversed by tuning the direction of the magnetic field , which is applied on the tunnel junction between the dots , to set t = tc .
spin - dependent conductance g and spin polarization p as functions of the fermi level with = u = 0 and various t . in this and
all following figures , the normal inter - dot tunneling coupling tc = 1 and the dots levels are 1 = 2 = 0 we now study how the dot - lead coupling configuration influences the spin filtering effect in fig . 3 by varying the value of . it is found that if the parameters are set to be t = tc and = r = /2 , the spin - down conductance remains to be zero for any , and then only is plotted . for non - zero , the transmission t( ) is(8 ) where 0 = 1 = 2 . since and
the spin - down transmission regardless of the choice of . the spin - up conductance is composed of one broad breit - wigner and one asymmetric fano resonance centered , respectively , at the bonding and antibonding states .
detail investigation of this spin - dependent fano line - shape can be found in our previous papers and we do not discuss it anymore here .
it should be indicated that the spin orientation of the nonzero conductance can be reversed by setting t = tc and = /2 + 2n with n is an integer .
the dependence of the spin - up conductance on the fermi level for fixed r = = /2 , t = tc and various . other parameters are the same as those of fig .
2 it is known that the coulomb interaction in the qds plays an important role and we now study if the spin filtering effect survives in the presence of it .
figure 4a shows that the conductance of the spin down electrons is still zero and that of the spin up shows typical fano resonance . due to the existence of the intra - dot coulomb interaction ,
moreover , the positions of the bonding and antibonding states can be readily exchanged by tuning the magnetic flux as shown in fig .
since the fano effect is a good probe for quantum phase coherence in mesoscopic structures , the tuning of its resonance position and the asymmetric tail direction is an important issue . to date
, much works have been devoted to this topic concerning both the charge and the spin - dependent fano effect .
but most previous works about the fano effect in qds ring ignored the coulomb interaction , especially when the spin degree of freedom is considered , and this limitation is supplemented here .
spin - dependent conductance g as a function of the fermi level for fix r = /2,u = 4 , t = tc and different . in this and the following figure , the solid and the dashed lines are for the spin - up and spin - down electrons , respectively in fact , to realize the rsoi in a tiny device such as the qds is somewhat difficult , and then we study if the spin filtering effect can be found in the absence of it . in fig . 5
, we set r = 0 and plot the two spin components conductance by varying tand the magnetic flux - induced phase factor . figure 5a shows that when t = tcand = + 2n withnis an integer , the conductance of the spin - up electrons still has finite value whereas that of the spin - down electrons is exactly zero .
moreover , to swap the spin direction of the non - zero conductance , one can simply tune tfromtcto tcwith unchanged magnetic flux as shown in fig .
5b . the peaks width and position of the non - zero conductance in fig .
5a , b are the same , indicating that one can flip the electron spin in the bonding and antibonding states without affecting its sate properties .
spin - dependent conductance g as a function of the fermi level for fix r = 0,u = 4 , = and different t
in conclusion , we have investigated the spin filtering effect in a double qds device , in which the two dots are coupled to external leads in a configuration transiting from serial - to - parallel geometry .
we show that by properly adjusting the spin - dependent inter - dot tunneling coupling strengtht , a net spin - up or spin - down conductance can be obtained with or without the help of the rsoi and the magnetic flux .
the spin direction of the non - zero conductance can be manipulated by varying the signs oft. the above means of spin control can be fulfilled for a fixed rsoi - induced phase factor , and then the qds in the present system can be either a gated or a self - assembly one , making it easier to be realized in current experiments .
this work was supported by the national natural science foundation of china ( grant nos . | we theoretically propose a double quantum dots ( qds ) ring to filter the electron spin that works due to the rashba spin
orbit interaction ( rsoi ) existing inside the qds , the spin - dependent inter - dot tunneling coupling and the magnetic flux penetrating through the ring . by varying the rsoi - induced phase factor , the magnetic flux and the strength of the spin - dependent inter - dot tunneling coupling , which arises from a constant magnetic field applied on the tunneling junction between the qds
, a 100% spin - polarized conductance can be obtained .
we show that both the spin orientations and the magnitude of it can be controlled by adjusting the above - mentioned parameters .
the spin filtering effect is robust even in the presence of strong intra - dot coulomb interactions and arbitrary dot - lead coupling configurations . |
extranodal involvement is seen in approximately 25% cases of nonhodgkin 's lymphoma ( nhl ) .
primary adrenal lymphoma ( pal ) is rare with fewer than 200 cases reported in english literature .
the majority of the patients with pal present with bilateral adrenal masses and diffuse large b - cell ( dlbcl ) type is the most common type on histology .
unilateral presentation and t - cell / natural killer ( t / nk ) cell histological type is rarer . due to the rarity of the disease
, there is a paucity of literature on the role of fluorine-18 fluorodeoxyglucose positron emission tomography / computed tomography ( f-18 fdg pet / ct ) scan in pal .
we report f-18 fdg pet / ct scan findings in a case of unilateral t / nk cell pal performed for staging and interim treatment response assessment .
a 41-year - old gentleman with no co - morbidities presented with the progressive left hypochondriac pain of 1-month duration .
ct guided biopsy with immunohistochemistry revealed tumor cells positive for leukocyte common antigen , cd3 , and weakly positive for cd56 ; while negative for cd20 , cd4 , and cd8 suggestive of high - grade nhl of t / nk cell immunophenotype [ figure 1 ] .
staging f-18 fdg pet - ct scan revealed increased metabolic activity in the left adrenal mass .
no focus of hypermetabolism was noted elsewhere in the body suggestive of stage i aex ( left adrenal ) [ figure 2 ] .
( methotrexate , dexamethasone , leucovorin , ifosfamide , etoposide , and l - asparaginase ) chemotherapy regimen .
interim fdg pet - ct for response assessment post four cycles of chemotherapy revealed complete metabolic and morphological regression of the primary left adrenal mass .
biopsy of the left adrenal mass : ( a and b ) photomicrographs showing features of nonhodgkin 's lymphoma with diffuse architecture composed of intermediate to large atypical lymphoid cells ( h and e , 4 and 40 respectively ) .
( h ) cd-8 ( 40 ) increased fluorodeoxyglucose uptake was noted in the left suprarenal gland on maximum intensity projected : ( a ) .
( c ) images of the staging positron emission tomography / computed tomography scan in case of biopsy proven adrenal lymphoma .
positron emission tomography / computed tomography scan done post four cycles of smile chemotherapy regimen revealed complete metabolic and morphological response ( d - f )
pal is defined as the presence of adrenal lymphoma without any evidence of nodal involvement or leukemia . although secondary adrenal involvement in nhl is seen in approximately 25% of cases , pal is rare comprising < 1% of nhl and 3% of extranodal nhl with < 200 cases reported in english literature .
most of the patients present with nonspecific symptoms such as abdominal pain , fever , and weight loss . in 60% cases ,
advanced age at diagnosis , large tumor size , increased ldh level , bilateral adrenal involvement ( regarded as stage iv disease ) , and adrenal insufficiency at the time of presentation are poor prognostic factors .
since adrenal gland is devoid of lymphoid or hematopoietic tissue , pal is believed to originate from differentiation of primitive totipotent mesenchymal cells .
, none of these theories has been conclusively proven due to the rarity of the disease .
there are only 5 - 6 cases of t / nk - cell type pal reported in the literature so far , most of them with bilateral adrenal involvement .
conventionally , ct scan is used as a first imaging modality for characterization of adrenal lesions .
t2-weighted magnetic resonance imaging with chemical shift sequences is also often used to differentiate benign from malignant adrenal masses .
f-18 fdg pet / ct scan has an established role in staging , restaging , interim response assessment , and prognostication of lymphomas .
various studies have shown higher accuracy of f-18 fdg pet / ct scan in differentiating malignant and benign adrenal masses .
yun et al . have shown that fdg pet has a 100% sensitivity , 94% specificity , and 96% accuracy for characterization of adrenal lesions .
however due to the rarity of the disease , there is a paucity of literature on the role of fdg pet / ct scan in pal . in our case ,
baseline fdg pet / ct showed intense uptake in the left adrenal mass with no other nodal or extranodal disease detected elsewhere in the body .
hence , in correlation with the biopsy findings , whole body fdg pet / ct played a paramount role in differentiating primary versus secondary involvement of adrenal gland .
a study by khong et al . assessing the role of mid - treatment fdg pet / ct for early response assessment of smile therapy in nk / t - cell lymphoma demonstrated that deauville score on mid and end treatment fdg
pet / ct is the only significant independent predictor of both overall survival and progression free survival . to the best of our knowledge
, this is the first case reported in the literature where a complete metabolic and morphological response was seen on interim fdg pet / ct in a case of unilateral pal of t / nk - cell type treated with smile regimen .
therefore , our case further reinforces the valuable role of fdg pet / ct for diagnosis , staging , and treatment response evaluation in pal .
| primary adrenal lymphoma ( pal ) is a rare malignancy often involving bilateral adrenal glands .
diffuse large b - cell is the most common histological type . unilateral presentation and t - cell / natural killer ( t / nk ) cell histological type is rarer .
we report fluorine-18 fluorodeoxyglucose positron
emission tomography / computed tomography scan findings in a case of unilateral t / nk cell pal performed for staging and interim treatment response assessment . |
to report a case of wolfram syndrome ( ws ) characterized by diabetes mellitus , diabetes insipidus , progressive optic atrophy , and deafness .
a 19-year - old female patient , a known case of diabetes mellitus type i from six years before , presented with progressive vision loss since four years earlier .
ws should be considered a differential diagnosis in patients with diabetes mellitus who present with optic atrophy , and it is necessary to perform a hearing test as well as collecting 24-h urine output .
wolfram syndrome ( ws ) is an autosomal recessive neurodegenerative disorder characterized by diabetes insipidus , diabetes mellitus ( non - autoimmune ) , optic atrophy , and deafness ( a set of conditions referred to as didmoad).1 , 2 , 3 the gene responsible for the ws , named wsf1 , encodes an endoplasmic reticulum membrane - embedded protein called wolframin that is expressed in pancreatic beta cells and neurons.4 , 5 , 6 the estimated prevalence of ws is 1 in 770,000 , and it is believed to occur in 1 of 150 patients with type 1 diabetes . affected patients usually develop insulin - requiring diabetes and optic atrophy in early childhood , and diabetes insipidus as they become teenagers or young adults .
in ws patients with diabetes insipidus , not only does vasopressin neuron loss occur in the supraoptic nucleus , but there is also a defect in vasopressin precursor processing .
other manifestations of ws include progressive sensorineural deafness , hydronephrosis ( due in part to the high urine flow in diabetes insipidus ) , and neurologic dysfunction .
why severe insulin - requiring diabetes develops is not known ; immunologic factors do not appear to be important .
affected individuals have a median life expectancy of 30 years , with early mortality credited to neurological disorders , urological abnormalities and infection .
differential diagnosis and treatment are difficult due to the variable presentation of symptoms . in the present study ,
a 19-year - old female patient , a known case of type i diabetes mellitus from six years before , presented to a private ophthalmology office .
her visual acuity reduced to 1/10 on both eyes . she had a history of nocturia and high urine output for five years , and after that , she had incontinency . in the previous two years , she had been avoiding difficulty and using self - intermittent catheterization four times a day . on ophthalmic examination ,
intraocular pressure was 15 mmhg in both eyes , and biomicroscopic examinations were completely normal .
on fundoscopic examination , she had bilateral optic atrophy without diabetic retinopathy ( fig . 1 , fig . 2 ) .
accordingly , ws was suspected by the ophthalmologist , who referred her to an endocrinologist .
investigations revealed polyuria ( 14 l per day ) , hypernatremia ( 156 meq / l ) , and hyperglycemia ( 351 mg / dl ) .
other laboratory values were : creatinine , 1.1 mg / dl ; urea nitrogen , 28 mg / dl ; k , 4.5 meq / l ; tsh , 2.5
a random urine analysis showed a urine specific gravity of 1.006 , and the results of 24-h urine collection obtained a urine specific gravity of 1.005 [ normal values : 1.0101.030 ] .
it was suspected that there might be an underlying cause for diabetes insipidus , due to the presence of a low urine specific gravity
subsequently , a urine and plasma osmolality was performed , which were 150 and 312 mmol / kg , respectively .
there was no change either in urine specific gravity or urine osmolality before and after the water deprivation test .
after nasal desmopressin administration , urine osmolality increased from 125 mosm / kg to 600 mosm / kg and serum osmolality increased from 281 mosm / kg to 328osm / kg . given to an increase in urine osmolality of more than 100% measured by the desmopression stimulation test
a few days later , the volume of urine collected in 24 h was within acceptable range .
a magnetic resonance imaging ( mri ) of the brain revealed the loss of the physiological hyperintense signal of the posterior pituitary gland ( bright spot ) on t1-weighted images , suggesting the diagnosis of central diabetes insipidus ( fig .
an audiologic examination revealed neurosensory deafness , and audiometry showed a bilateral high - frequency sensorineural hearing loss .
the bladder wall had a trabecular pattern , and the urinary tract was dilated on both sides .
the patient 's sister had similar symptoms , but she did not cooperate for further evaluation .
ws was first described in 1938 by wolfram and wagener as a hereditary syndrome characterized by diabetes mellitus and optic atrophy acquired early in life .
subsequent reports added diabetes insipidus and deafness to the syndrome , which develop in approximately 73 and 62% of sufferers , respectively.3 , 12 the minimal criteria for diagnosis are juvenile - onset diabetes and optic atrophy ; however patients also present with additional complications , hence the acronym didmoad ( diabetes insipidus , diabetes mellitus , optic atrophy , and deafness ) is used .
the diagnosis is established in individuals of all ages in whom two pathological wfs1 or cisd2 mutations are identified .
diabetes mellitus is a key feature of ws , which is usually the first sign of the disease ( median age at diagnosis , 615 years ) , and optic atrophy ( median age at diagnosis 11 years ) .
the mean age of presentation of diabetes mellitus has been reported to be 5 4 years .
there are multiple differences between the presentation and course of autoimmune type 1 diabetes and diabetes of ws .
namely , patients affected with ws have a low incidence of diabetic ketoacidosis at the time of diagnosis ( only 3% compared to 30% in type 1 diabetes ) , a much lower insulin requirement in the first several years after diagnosis , rare microvascular complications , and rare presence of diabetes antibodies .
patients with ws show smaller glycemic variability than individuals with type 1 diabetes mellitus , and this may be associated with persistent residual insulin secretion .
a loss of vasopressin - producing neurons in the hypothalamus has been well documented in this disease and is thought to be the cause of ws - associated diabetes insipidus.17 , 18 neuroradiologists have reported a loss of signal intensity in the posterior pituitary , indicating an absence or degeneration of the neurohypophysis18 , 19 ; some patients have been found to have empty sella .
patients with ws demonstrate progressive ophthalmologic symptoms that usually occur after diabetes mellitus . besides optic
atrophy , constriction of visual fields and declined visual acuity and color vision are the other ophthalmological findings in ws ; however , diabetic retinopathy is rarely observed .
al - till et al performed a study to investigate ophthalmologic abnormalities in fifteen patients with ws .
of 15 patients with ws reviewed in this study , 93.3% had optic atrophy , 92.9% had color deficit , 66.6% had cataract , 30% had pigmentary retinopathy , and 20% had diabetic retinopathy .
the ophthalmic signs were a progressive decrease in visual acuity , constriction of the peripheral visual field with or without central scotoma , color vision disturbances , and bilateral optic disc atrophy .
recently , the retinal thinning has been proposed as a marker of disease progression in patients with ws .
deafness in ws is commonly a high - frequency , symmetric , sensorineural hearing loss , usually manifesting in the second or third decade with a relatively slow rate of deterioration.26 , 27 some studies have reported urinary tract abnormalities ( hydroureter , urinary incontinence , recurrent infections ) in patients with ws , that these abnormalities are expected in about 66% of patients .
urinary tract abnormalities include obstruction of the ureters , an atonic bladder with a large capacity , high pressure bladder with sphincteric dyssynergia , and incontinence .
urinary tract dilatation is presented in 45% of patients with ws , which may be secondary to chronic high urine flow rate or neurodegeneration in different levels of the urinary tract .
differential diagnosis of ws includes : ( 1 ) mitochondrial disorders : maternally inherited diabetes mellitus and deafness , leber hereditary optic neuropathy ; ( 2 ) thiamine - responsive megaloblastic anemia , diabetes , and deafness ; ( 3 ) autosomal dominant optic atrophy ; ( 4 ) x - linked charcot - marie - tooth disease type 5 ; ( 5 ) deafness , dystonia , optic neuronopathy syndrome ; ( 6 ) friedreich ataxia ; ( 7 ) bardet - biedl syndrome ; ( 8) alstrom syndrome ; and ( 9 ) congenital rubella syndrome .
the association of diabetes mellitus with optic atrophy also occurs in friedreich 's ataxia , refsum disease , alstrom syndrome , lawrence - moon syndrome , kearn - sayre syndrome , and deafness and diabetes in the3243 mitochondrial dna mutation .
the pathogenesis of the disease remains unknown , but genetic linkage studies have shown that the mutations of the wfs1 gene are responsible for the symptoms in 90% of cases meeting specific wfs diagnostic criteria .
the wfs1 gene encodes an 890-amino - acid protein called wolframin , a putative multispanning membrane glycoprotein of the endoplasmic reticulum . although no function has yet been ascribed to wolframin
; however , its localization to the endoplasmic reticulum suggests it can play a role in calcium homeostasis , membrane trafficking and protein processing .
there is currently no cure for ws , but there are treatments for some of the features .
diabetes mellitus is treated with insulin , and diabetes insipidus with vasopressin . while hearing aids can help with hearing loss , there is unfortunately no treatment for vision loss .
renal problems may be treated by catheterization ( passing a thin , flexible tube into the bladder to drain away urine ) , and some of the neurological symptoms can be treated with medication .
based on the findings of the present case , it is highly recommended that , in patients with diabetes mellitus who have optimal blood sugar presenting with polyuria and polydipsia , we need to do urine specific gravity to prove the presence of diabetes insipidus . in such patients , performing an ophthalmologic evaluation can probably reveal this rare disorder of wolfram syndrome .
in addition , ophthalmologists should be aware that in patients presenting with diabetes mellitus and optic atrophy without any signs of diabetic retinopathy , it is necessary to perform a hearing test as well as collect and analyze 24-h urine output .
thus , awareness of this condition and timely diagnosis is important for improving patient prognosis , anticipating associated complications , and enabling timely genetic counseling for family members . | purposeto report a case of wolfram syndrome ( ws ) characterized by diabetes mellitus , diabetes insipidus , progressive optic atrophy , and deafness.case reporta 19-year - old female patient , a known case of diabetes mellitus type i from six years before , presented with progressive vision loss since four years earlier .
on fundoscopic examination , she had bilateral optic atrophy without diabetic retinopathy .
the patient also had diabetes insipidus , neurosensory deafness , and neurogenic bladder.conclusionws should be considered a differential diagnosis in patients with diabetes mellitus who present with optic atrophy , and it is necessary to perform a hearing test as well as collecting 24-h urine output . |
it is the body 's immediate and carefully orchestrated response to pathogens , noxious stimuli , or physical injury .
in addition , responsiveness to plasma- and cell - derived inflammatory mediators reflects a more general role for inflammation in restoring functionality of the system to basal homeostatic set points . the process , by which acute inflammation is initiated and develops via molecular and cellular pathways , is well defined . in case the body does not succeed in eliminating or neutralizing this condition over time , a chronic inflammatory state arises and resets the body 's reference points and will become maladaptive .
this implicates elevated concentrations of cytokines and chemokines including interleukin- ( il- ) 1 , il-1 , il-6 , il-8 , il-10 , il-18 , tnf- , and alarmins such as high - mobility group box 1 ( hmgb1 ) .
these molecules have also been proven to be involved in the progression of chronic inflammatory disorders , infections , and fibrotic diseases as well as cancer , autoimmune , and ageing - associated disorders .
it is demonstrated that il-1 and il-18 driven inflammation , through inflammasome activation , is initiated by recognition of endogenous or exogenous danger signals .
il-1 , one of the main classic instigators of inflammation is , together with il-18 , released from the cell upon activation of the inflammasome .
it has the ability to affect various biological properties and has several roles in the proinflammatory response , including activation of the endothelium and leukocytes . back in 1984
it was predicted that il-1 was responsible for many of the acute responses to infection and inflammation .
il-18 , a member of the il-1 cytokine super family , is recognized as an important regulator of innate and acquired immune responses .
its importance is derived from its prominent biological property of inducing interferon ( ifn ) . il-18 is expressed at sites of chronic inflammation , in autoimmune diseases , in a variety of cancers , and in the context of numerous infectious diseases .
in addition to il1 and il18 , basic fibroblast growth factor ( bfgf ) and hmgb1 are unconventionally released under caspase-1 activated conditions following a number of posttranslational modifications .
therefore , we included bfgf as well as hmgb1 to be reviewed among the factors that could possibly be released from the epithelial cells upon inflammasome activation . for hmgb1 , its earliest functions were described as a nonhistone dna - binding nuclear protein .
it forms highly inflammatory complexes with single stranded ( ss ) dna , lipopolysaccharide ( lps ) , il-1 , and nucleosomes and interacts with toll - like receptor ( tlr ) 9 , tlr4 , il-1r , and tlr2 and the receptor for advanced glycation end - products ( rage ) .
it has also been reported that hmgb1 can signal via the well - characterized nuclear factor-b pathway to induce a release of proinflammatory cytokines , including tnf- and il-1. bfgf , a mitogenic agent , is not directly proinflammatory but can potentiate the recruitment of immune cells to the site of inflammation .
this growth factor supports the maintenance of undifferentiated cells and is involved in tissue repair , regeneration , and proliferation .
it is a potent fibrogenic mediator that can be induced by a variety of molecules in different cell types such as by silica in lung epithelial cells [ 5 , 6 ] from which it is released in an inflammasome - dependent mode - of - action and potentially linked to fibroblast proliferation .
activation of inflammasome - dependent mediator release is typically a very potent reaction and by virtue of the potentially destructive proinflammatory effects of uncontrolled cytokine and alarmin release their reduction and shutdown mechanisms ( e.g. , il-1 receptor antagonist ( il-1ra ) signaling ) should therefore be tightly regulated by innate sensors . to date , a number of cytosolic receptors are successful in the recognition of conserved molecular patterns termed pathogen- or danger - associated molecular patterns ( pamps or damps ) , by initiating the formation of an inflammasome .
these include the nucleotide - binding oligomerization domain receptors , in short nod - like receptor ( nlr ) protein family members nlrp1 , nlrp3 , nlrp6 , nlrp7 , nlrp12 , nlrc4 , and nlrc5 as well as the non - nlr pyrin and hin200 domain - containing ( pyhin ) protein family members absent in melanoma 2 ( aim2 ) , myeloid nuclear differentiation antigen ( mnda ) , interferon inducible protein x ( ifix ) , and interferon alpha - inducible protein 16 ( ifi16 ) which are all able to oligomerize into a functional inflammasome [ 911 ] .
this implies the formation of a multiprotein complex consisting otherwise also of an adaptor protein , apoptosis - like speck protein containing a card ( asc ) , and il-1 converting enzyme ( ice , caspase-1 ) , the enzyme responsible for maturation of proinflammatory cytokines . upon this assembly , caspase-1 undergoes autocatalytic activation into heterotetramers , which further enables the cleavage of its substrates pro - il-1 and pro - il-18 into mature il-1 and il-18 , and the unconventional release of bfgf and alarmins by the cell as is illustrated in figure 1 .
in addition , caspase-1 is associated with the release of il-1 , although these mechanisms are poorly understood .
moreover , their release may be accompanied by pyroptosis , an incompletely characterized proinflammatory mode of cell death . upon activation by a myriad of signaling pathways these inflammasome - dependent mediators
are strongly expressed by monocytes , tissue macrophages , and dendritic cells but are also produced by b lymphocytes , natural killer ( nk ) cells , and epithelial cells . activated inflammasomes and subsequently activated and released cytokines and alarmins play a key and well - controlled role in innate immunity of the lung mucosa and interstitial microenvironment . as mediators of the acute phase of inflammation they are extremely important for the immune system to react to invading pathogens .
it is however equally important that inflammasomes distinguish pathogenic from nonpathogenic commensals , implying that a disturbance in normal danger signaling through the inflammasome can act as a master switch between tolerance and sensitization in many actively participating tissues [ 1519 ] .
the activation of inflammasomes in myeloid innate immune cells as well as their contribution to acute and chronic inflammatory diseases has been characterized profoundly over the past 12 years by in vivo and in vitro research .
nevertheless , we are still far away from understanding how these molecules actually become activated , how they exert their function , and how they can be targeted in therapy . aside from the specialized cells of the immune system that evolutionary developed to protect organ systems ,
most foreign pathogens and noxious stimuli are also encountered by epithelial cells in a barrier lining the organs that are in most proximal contact with the exterior environment .
these are the tissue specific mucosae of the skin , the lung , the gut , and the urogenital tract , as well as nonkeratinizing squamous epithelial cells of the oral mucosa .
the epithelium is more and more appreciated to be less passive than what was assumed before and evidence is mounting that it participates not only in receiving and relaying inflammatory signals , but in functions as an initial sensor of danger and executor of the response as well .
we therefore review here the literature on the presence and functionality of inflammasomes in epithelial cells of the various organs exposed to the exterior milieu in response to reported insults .
the aim of this review is to deliver better understanding of inflammatory responses of first - line barrier epithelium in multiple organs and mucosal immunity and encourage further laboratory research to dissect out the role of epithelial inflammasomes to these processes , with more effective therapies for the numerous debilitating diseases with an acute and chronic inflammatory component as the ultimate goal .
in addition to its properties as a physical barrier , the skin has many active defense mechanisms .
keratinocytes can detect microbial or nonmicrobial danger signals and elicit an immune response prior to the infiltration of myeloid cells .
although the action and importance of il-1 , il-18 , and hmgb1 in inflammatory skin disorders are not completely understood , dysregulation of these inflammasome - dependent molecules is an attractive concept that might play a role in many inflammatory abnormalities of the skin . in 1990 already
, protein levels of immunoreactive il-1 were shown to be elevated in psoriatic lesions whereas the amount released by normal keratomes or cultured keratinocytes was undetectable .
the presence of il-1 was suggested to be due to a novel mechanism of posttranslational processing in the epidermis .
this mechanism was identified in 1997 as caspase-1 dependent cleavage which could be induced in human keratinocytes in response to inflammatory and immunologic stimuli .
later , keratinocytes of the nondiseased skin were scarcely stained positive for nlrp1 and nlrp3 and aim2-like receptor ( alr ) inflammasomes .
these expression patterns suggest that multiple inflammasomes are likely to play a role in the first line of defense against noxious molecules . with respect to different functional inflammasomes in the skin
, human keratinocytes express aim2 and respond to poly(da : dt ) dsdna with il-1 secretion .
recently , these findings have been supported by detection of active il-1 and cleaved caspase-1 in human papillomavirus ( hpv ) infected skin , suggesting inflammasome activation by viral dna .
watanabe et al . also demonstrated that the nlrp3 inflammasome is present and can be activated in keratinocytes as in animal models of contact hypersensitivity this inflammasome was identified as a key regulator of innate immunity .
keratinocytes are obviously also barrier cells against environmental pollutants such as tio2 and sio2 . it was shown that these environmental particles in the nanosize could induce cleavage of caspase-1 and secretion of il-1 .
caspase-1 activity of stratum corneum and serum il-18 level were also increased in patients with netherton syndrome , a disease characterized by chronic skin inflammation . in a tetanus toxoid - dependent experimental model using cocultures of monocytes and keratinocytes ,
others furthermore observed high levels of il-1 when tetanus toxoid and keratinocytes were present , indicating that skin epithelial cells are able to secrete caspase-1 and a source for il-1 ( figure 2 ) . in skin injury models relevant to the development of cancer , irradiation with a physiological dose of uvb induced secretion of pro - il-1 and of mature and active il-1 and il-18 in a caspase-1 dependent fashion [ 31 , 32 ] .
other studies of uvb overexposure in sunburned skin demonstrated activated inflammasomes and uv light exposure stimulated bfgf and hmgb1 release by keratinocytes as well [ 34 , 35 ] . in an allergic skin disease model , mite allergen dermatophagoides pteronyssinus 1
( der p1 , a major allergen of house dust mite ) , is recognized as a danger signal , activated caspase-1 , and induced release of il-1 and il-18 from keratinocytes which was dependent on the cysteine protease activity .
moreover , der p1 stimulated assembly of the inflammasome by recruiting asc , caspase-1 , and nlrp3 to the perinuclear region .
the data reviewed in this section demonstrate that keratinocytes are a potent source of cytokines and alarmins upon contact with a broad spectrum of activators .
it is clear that keratinocytes do not only have a passive role as target cells in the process of inflammation but also act as stimulators of the initiation and maintenance of local immune reactions .
the oral mucosa is exposed to high density and diversity of potential microbial pathogens such as gram - positive and gram - negative bacteria as well as fungi and others and therefore has the important function of acting as a physical barrier and responding to microbial growth and invasion .
the inflammasomes , as intracellular immune receptors , are thus likely to be important mediators of the inflammatory response in gingival epithelial cells . in a recent study depletion of nlrp3 by sirna abrogated the ability of atp to induce il-1 secretion in infected cells .
atp is sensed by purinergic receptors such as p2x , ligand - gated ion channel 4 ( p2x4 ) .
besides numerous reports on the role of p2x7 receptors in atp - mediated inflammasome activation and mature il-1 production in macrophages in vitro , recently in gingival epithelial cells that were stimulated with extracellular atp , a role for p2x7 dependent - ros production in the activation of the inflammasome was revealed ( figure 2 ) .
interestingly , in addition to the nlrp3 inflammasome , a different inflammasome containing nlrc4 appeared to function in the protection against infection with candida albicans in the mucosal lining of the mouth and intestines rather than in immune cells .
no further evidence can be found on how immune homeostasis via inflammasome signaling is maintained in this environment .
these studies reveal the epithelial - specific roles of the nlrp3 and nlrc4 inflammasome in innate immune response of the oral mucosa .
in organs where a variety of cell types come in intimate contact with commensals and potentially pathogenic microbes , such as the gut , the regulation and maintenance of normal intestinal mucosal barrier function is primordial for the host 's survival and fitness . when cellular integrity and functioning of tight junctions between adjacent epithelial cells is disrupted barrier impairment is easily provided resulting in inflammation and the induction of tissue - repair responses .
the lack of control of this inflammatory condition is suggested to aggravate in the direction of detrimental chronic inflammation in the gut .
inflammasome - dependent mediators such as il-1 , il-18 , and hmgb1 have been identified as potent promoters of intestinal pathology , which suggests that targeting these mediators may represent a useful therapeutic approach in inflammatory bowel disease ( ibd ) .
initially , observations suggested that induction of il-1 mrna in enterocytes was causally related to the subsequent inflammatory changes seen in a model of acute experimental colitis .
it was proposed that colon epithelial cells were programmed to provide a set of signals for the activation of the mucosal inflammatory response in the earliest phases after microbial invasion [ 42 , 43 ] .
later , a few studies demonstrated that intestinal epithelial cells ( iec ) , continuously exposed to dietary molecules , microbial antigens , and environmental influences , played a much more active role in the host immune and inflammatory response via the secretion of a variety of cytokines limited to not only il-1 , but also il-1 and il-8 [ 4446 ] . that same year , for the first time , mouse iecs were proven to be the main producers of il-18 , formerly called interferon - gamma - inducing factor under normal physiological conditions , suggesting that its constitutive expression in iecs may have an important role in the induction of mucosal immunity .
two years later , il-18 was demonstrated to be localized and increasingly expressed in intestinal mucosal cells of patients with crohn 's disease ( cd ) [ 49 , 50 ] . within this same period ,
posttranslational activation of il-18 by caspase-1 cleavage was identified to occur in response to viral and bacterial infections [ 51 , 52 ] .
specifically , a year before inflammasomes were characterized , cleavage of il-18 in porcine intestinal mucosa by salmonella choleraesuis was demonstrated , indicating that caspase-1 activation of il-18 may be a key step in mucosal immune response to bacterial invasion .
expression of il-18 in human gastric mucosal epithelial cells was also increased by helicobacter pylori infection or by lactoferrin [ 54 , 55 ] .
recently , human iecs showed the ability to release il-18 upon salmonella treatment in a caspase-1 dependent fashion and release hmgb1 in their culture medium upon stimulation with lps and a mixture of tnf- , il-1 , and ifn- .
microbial activity is required to be constantly monitored in the epithelial lining of the gut .
it has become evident that a range of inflammasome family members within different cell types ( e.g. , epithelial and hematopoietic cells ) accomplish different , but often complementary , functions , as watchful guardians eliciting mucosal immune responses when activated .
the most intensively studied inflammasomes in the gut , the nlrp1 , nlrp3 , nlrp6 , and nlrc4 inflammasomes , have been shown to regulate a number of common intestinal mucosal infections .
for instance , nlrp3 and nlrc4 activation in the intestinal epithelium is essential for regulation of permeability and epithelial regeneration through sensing of commensal microbes and has been shown to protect against mucosal pathogens [ 60 , 61 ] ; however , excessive inflammasome activation within the lamina propria contributes to severe intestinal inflammation .
moreover , whereas the nlrp6 inflammasome subtype regulated colonic microbial ecology and risk for colitis , it was also shown to be involved in control of epithelial self - renewal and colorectal carcinogenesis upon injury .
otherwise , nlrp6 inflammasome - deficient mice have been shown to be unable to clear enteric pathogens from the mucosal surface , rendering them highly susceptible to persistent infection .
additionally , recent findings suggest that both hematopoietic- and nonhematopoietic - derived nlrp12 contributed to inflammation in an experimental colitis model , but the latter dominantly contributed to tumorigenesis .
herein , nlrp12 was profiled as an important add - on in the inflammasome repertoire and new player in colonic inflammation and tumorigenesis .
together , these studies reveal intensive and integrated signaling from multiple inflammasomes to regulate inflammation - induced ibd and colon cancer .
in addition , unpublished data report the upregulation of most inflammasome sensor subtypes ( nlrp1 , nlrp3 , nlrp12 , nlrc4 , aim2 , ifi16 , mnda , and pyhin1 ) in the colonic mucosa of active ibd patients , with the double - stranded ( ds ) dna responding pyhin inflammasome subtypes ( aim2 and ifi16 ) showing the strongest increase .
these data are accompanied with enhanced levels of il-1 in primary iecs in culture following dsdna exposure .
immunohistochemical data show , next to inflammatory cells , an epithelial presence of these inflammasome sensor subunits and some of their effector molecules ( casp1 and hmgb1 ) ( unpublished data ) .
together , this indicates that a more profound focus on non - nlr signaling may be justified in ibd .
the multiple activators of a broad spectrum of inflammasome subtypes implying caspase-1 activation and subsequent secretion of specific readouts in iecs are summarized in figure 3 .
activation of intestinal inflammasomes in different lineages of cells regulates physiological reactions , and their hyperactivation or absence can lead to deleterious consequences such as inflammation or cancer progression as shown in different models . for instance , following tissue damage using the iec cytotoxic agent dextran sodium sulphate ( dss ) , the nlrp3 inflammasome assembles , leading to the production of il-18 , which is then released at the mucosal sites .
defective nlrp3 inflammasome subtype activation was shown to protect against loss of epithelial integrity and mortality during dss - induced experimental colitis , suggesting that genetic and environmental factors may activate the nlrp3 inflammasome .
in addition , their absence rather than their overproduction could be considered deleterious , indicating a multifaceted regulatory role of nlrp3 in intestinal inflammation .
, on the other hand , demonstrated that nlrp6-deficient mice were highly susceptible to experimental colitis .
further , it was shown in humans with a leaky intestinal barrier ( such as seen in ibd patients ) that tio2 microparticles were taken up by iec and could activate the inflammasome and induce il-1 and il-18 secretion in the mucosa of crohn 's disease patients , representing a possible mode of aggravation of inflammation in susceptible individuals .
others have shown that 2,4,6-trinitrobenzene sulfonic acid ( tnbsa ) was unable to induce significant colitis in il-18 deficient mice and that administration of an il-18 neutralizing antibody resulted in a dramatic attenuation of mucosal inflammation .
the proposed function for the nlr and non - nlr inflammasomes is to regulate secretion of il-18 that stimulates epithelial cell barrier function and regeneration , whereas , in hematopoietic cells , inflammasome activation would have a proinflammatory effect [ 63 , 71 ] .
this suggests that signals produced by the iecs may play an important role in inducing the early host inflammatory response to infection and raises the possibility that interventions that directly target production of inflammatory cytokines by iecs might alter the course of disease .
when comparing results of studies by different groups , one should take into consideration that many of the observed effects may be explained by defective inflammasome regulation of the composition of the microflora coupled with differences in native microflora in different facilities .
targeting mediator release that is associated with mucosal inflammasome activation in the gut could lead to better understanding of which pathological aspects of inflammation and subsequent increases in permeability contribute to the development of ibd .
barrier epithelia , such as the airway epithelial cells lining the respiratory tract , fulfill multiple functions essential for tissue homeostasis .
they are , because of the immense surface area that is in intimate contact with the environment , a primary target of attack by microorganisms and potentially harmful factors during every single breath .
a vicious cycle of exaggerated responses to chronic stimuli or aberrant responses to rather innocent agents may result in chronic inflammation with permanent structural changes in barrier properties , including smooth muscle hyperplasia , airway remodeling , and fibrosis .
the importance of engagement of pattern recognition receptors ( pprs ) and their activation is demonstrated via experimental studies in knockout mice .
these resulted in evidence suggesting a deleterious role for excessive production of the inflammasome - dependent proinflammatory cytokines and danger signals il-1 , il-18 , and hmgb1 and the growth factor bfgf which possess multiple pathogenic properties that could be further enhanced during episodes of disease exacerbations [ 7276 ] .
because the localization and the impact of inflammasome sensor activation in airway epithelial cells associated with pulmonary inflammation have yet to be revealed , the activation of different inflammasomes in lung epithelium in response to triggers relevant to the main chronic inflammatory diseases , asthma , copd , pulmonary fibrosis , and pneumoconiosis , mainly in in vitro settings is summarized in this section .
historically , with respect to evidence of inflammasome activation or mediator release from lung epithelium one has to go back more than a decade prior to the first characterization of the inflammasome .
immunoreactive il-1 was shown to be released from bronchial epithelial cells exposed to toluene diisocyanate or nitrogen dioxide [ 78 , 79 ] and in tracheal biopsy material from individuals exposed to endotoxin - contaminated grain dust .
a few years later , in 1996 hastie et al . showed low but significantly higher amounts ( 2-fold ) of il-1 released from bronchial epithelial cells from allergic compared to nonallergic individuals following segmental challenge with ragweed .
moreover , in experiments with exposure to another allergen , der p1 , cultured human airway epithelial cells were shown to release il-1 . in 1998 ,
the il-1 release for the first time was linked to ice expression in alveolar epithelial cells upon respiratory syncytial virus ( rsv ) infection .
interestingly this study showed that this occurred in the absence of apoptosis , which could imply that epithelial cell death occurred through what is now known as pyroptosis .
different animal models of pulmonary fibrosis have been developed to investigate the pathogenic mechanism and potential therapies for idiopathic pulmonary fibrosis ( ipf ) .
the most common is the bleomycin model in rodents ( mouse , rat , and hamster ) . in 2001 , caspase-1 mrna expression was shown to be elevated in mice treated with bleomycin and bronchiolar and alveolar epithelial cells , as well as myeloid cells showing increased caspase-1 immunoreactivity in both nucleus and cytoplasm .
a decade later , it was suggested that inflammasome signaling in airway epithelial cells may play an important role in the pathogenesis of diseases like copd , as compounds such as lps and cpg were found to induce the releases of il-1 from human bronchial epithelial cells .
next to these environmental triggers , mechanical stretch was shown that same year to induce enhanced il-1 levels in the supernatants of alveolar epithelial cells . in recent years
the panel of mediators able to activate the inflammasome - dependent caspase-1 activity and il-1 release from ( primary ) lung epithelial cells has expanded rapidly to include pseudomonas aeruginosa , simvastatin , influenza a [ 19 , 87 , 88 ] , rsv , and rhinovirus .
the membrane attack complex of complement , apart from its classical role of lysing cells , can also trigger a range of nonlethal effects on cells , including driving inflammation .
recent findings demonstrated that sublytic attack by the membrane attack complex of complement leads to caspase-1 activation as well as il-1 secretion in primary human lung epithelial cells .
a panel of inflammasome - dependent mediators was shown to be released by bronchial epithelial cells following crystalline silica exposure and tran et al . demonstrated induction of il-1 and nlrp3 protein by the proinflammatory stimulus lps and the combination of ifn- with lps in primary cell cultures of nhbe cells .
hirota and his colleagues characterized airway epithelial nlrp3 inflammasome - mediated immune responses to urban particulate matter exposure and found significant increases in airway epithelial nlrp3 inflammasome - mediated production of il-1 in vitro , results that were corroborated in vivo . for interleukin-18 ,
a prolific cytokine involved in many immune responses already issued , literature research revealed that its immunoreactivity in airway epithelial cells was first investigated during early stages of host defense within the bronchial epithelium of biopsies obtained from control subjects and patients with sarcoidosis or asthma .
later , western blot analysis showed that the 18.3 kda mature form of il-18 appeared in whole cell lysate of mycobacterium tuberculosis - stimulated alveolar type ii cells , whereas both nonstimulated and mycobacterium tuberculosis - stimulated alveolar type ii cells contained abundant 24 kda pro - il-18 .
these results indicated that mycobacterium tuberculosis upregulates il-18 expression at both transcriptional and posttranscriptional levels , implying the involvement of caspase-1 enzymatic activity and therefore inflammasome activation .
piper et al . furthermore found that il-18 was released from rhinovirus - infected lung epithelia .
the release was not associated with cell death but was dependent on caspase-1 catalytic activity .
the endogenous danger protein hmgb1 was shown to be released from a549 cells infected with virulent legionella pneumophila in association with caspase-1 activity .
hmgb1 levels were furthermore found to be elevated in cell supernatant from rat alveolar type ii cell monolayers that underwent scratch wounding . moreover , mechanical stretch significantly increased hmgb1 protein expression in a549 cells .
these results are important in the context of injury , since epithelial crosstalk to neighboring cells is important for normal as well aberrant repair , such as in the case of fibrosis .
hmgb1 was included in the panel of inflammasome - dependent mediators that were released following crystalline silica exposure of bronchial epithelial cells .
epithelial cells express and secrete not only cytokines and alarmins upon exposure to endogenous or exogenous inflammasome activators but also bfgf .
the fgfs are involved in morphogenesis , wound repair , inflammation , angiogenesis , and tumour growth and invasion and require the glycosaminoglycan ( gag ) side chains of heparin sulphate proteoglycans for high affinity binding to their specific receptors .
late 20th century , bronchial epithelial cells were shown to secrete bfgf which positively impacted myofibroblast proliferation in an animal model of asthma . a role for epithelial cells in the expression and release of bfgf from heparan sulphate binding sites in bronchial asthma
the lung epithelium is a major source of bfgf as shown by rhinovirus - induced bfgf release in a model that mimics features of airway remodeling .
we furthermore showed that crystalline silica exposure of bronchial epithelial cells caused bfgf release which was inflammasome- and particle uptake - dependent .
a pivotal role of surface reactivity of crystalline silica to inflammasome activation was recently demonstrated in cultures of epithelial cells with evidence of the inhibitory capacity of the antioxidant trx to inflammasome activation .
importantly , our studies showed that the panel of silica - induced nlrp3 inflammasome - dependent mediators released from airway epithelium leads to fibroblast proliferation , a characteristic of multiple lung diseases .
, in which it is evidenced that multiwalled carbon nanotubes induce a nlrp3 inflammasome - dependent , but tgf- independent , profibrotic response in human bronchial epithelial cells . in contrast , there are publications that demonstrate that lung epithelial cells are not able to secrete il-1 upon exposure to different microorganisms and particulates among others [ 102 , 103 ] .
this section however summarizes a vast body of evidence that lung epithelium participates in early first - line immune defenses via activation of the inflammasome .
the expression of il-18 , il-1 , and bfgf as well as hmgb1 by these cells demonstrates its participation in the initial response to encounters with foreign molecules .
the described mediators may play a prominent role in the cascade of subsequent steps of the immune response in an autocrine and paracrine as well as chemotactic manner . to date , only a subset of inflammasomes has been described in lung epithelial cells so far ( figure 4 ) .
nlrp1 was reported to contribute to the immune response in lung epithelial cells and alveolar macrophages .
nlrp3 inflammasome presence and activation in lung epithelial cells was demonstrated as well [ 92 , 93 ] .
of most caspase-1 activating inflammasomes that have been studied well , nlrp12 is a unique nlr that has been shown to attenuate inflammatory pathways in biochemical assays and mediates the lymph node homing of activated skin dendritic cells in contact hypersensitivity responses .
although its expression was shown in lung cells , the overall development of allergic airway disease and airway function was not significantly altered by overall nlrp12 deficiency .
this suggests that nlrp12 does not play a vital role in regulating airway inflammation in this model . upon rhinovirus pathogenesis ,
the contribution of nlrp3 and nlrc5 inflammasomes and il-1 secretion in rhinovirus pathogenesis was investigated and revealed that both inflammasomes act in a cooperative manner during the assembly by sensing intracellular ca fluxes and triggering il-1 secretion in primary human bronchial epithelial cells .
additionally , the importance of inflammasome signaling in animal models representing a cadre of lung diseases such as asthma , copd , and acute lung injury as well as fibrosis and pneumoconiosis among others has been shown by many groups [ 106114 ] and was recently reviewed by brusselle et al . .
this section evidences that the surface epithelium of the conducting airways can be considered a constitutive primary participant in innate immunity with strong evidence that epithelial dysfunction is involved in the development of inflammatory disorders of the lung and could be a plausible target for therapeutic interventions .
often though , as indicated in the preceding paragraph the importance of inflammasome activation in the epithelium in animal models is not primarily approached .
therefore conditional knockout models or epithelial - specific transgenic animal studies will be a necessity .
with respect to cells lining the urogenital tract , evidence suggests that inflammasomes , next to other pprs , have important roles in associated diseases through regulation of inflammatory and tissue - repair responses to infection and injury .
first , on the subject of human kidney diseases such as wegener 's granulomatosis and in experimental models of glomerulonephritis , glomerular as well as tubular epithelial cells have been shown to synthesize and release il-1 , constitutively [ 117119 ] . in a recent study that analyzed the processing of caspase-1 , il-1 , and il-18 after unilateral ureteral obstruction ( uuo ) in mice reflecting chronic kidney disease ,
it was shown that nlrp3 has a biological function in both hematopoietic and renal epithelial compartments during renal injury .
additionally , in models of ischemic tubular necrosis and obstruction - induced epithelial - mesenchymal transition , an important role for caspase-1 and il-18 has been demonstrated under hypoxic conditions and in the absence of vascular effects [ 120122 ] .
other cells lining epithelial tracts in contact with the environment conveying inflammasomes are prostate epithelial cells expressing aim2 with increased caspase-1 activity in an experimental model of benign prostate hyperplasia ( bph ) , and human cervical epithelial cells expressing aim2 and ifi16 inflammasomes following chlamydia trachomatis and herpes simplex virus 2 , respectively [ 123125 ] .
although the amount of literature on inflammasome activation in these organs is relatively scarce , other studies demonstrate a pivotal role of the presence and activation of various inflammasomes in the epithelium of urogenital organs exposed to the environment [ 126128 ] ( figure 5 ) .
they are important guardians for the detection of danger signals and the consecutive initiation of an inflammatory response .
as presented in this review , each organ and cell type express different sensor subtypes with discrepancy in the release of various mediators .
it should be emphasized that it is very possible that manifold inflammasomes are important in multiple epithelial cell types and become activated to either overcome detrimental signaling or to cooperate in a constructive fashion combating the disease .
likewise , with respect to relatively lower concentrations of cytokines released from epithelial cells versus the myeloid compartment , it could be considered that first - line barrier epithelial cells , in contact with many potential danger signals , preferably should not produce high amounts of these very potent inflammatory cytokines and alarmins as it would be harmful for the microenvironment to have a constant high - alarm situation .
additionally , many more epithelial cells are present in these organs as opposed to , for instance , macrophages ; therefore activated epithelial cells may relay equally large and biologically significant immune signals that build up the important contribution in global inflammasome activation at organ level .
this review demonstrates that inflammasome activation and subsequent secretion of alarming proteins is not restricted to macrophages , indicating that epithelial cells should be considered as highly important cells in innate immune signaling . in future research
, epithelial - specific conditional knockout models and transgenic animal studies will be a necessary approach to determine this important contribution more profoundly . | the epithelium regulates the interaction between the noxious xenogenous , as well as the microbial environment and the immune system , not only by providing a barrier but also by expressing a number of immunoregulatory membrane receptors , and intracellular danger sensors and their downstream effectors . amongst these
are a number of inflammasome sensor subtypes , which have been initially characterized in myeloid cells and described to be activated upon assembly into multiprotein complexes by microbial and environmental triggers .
this review compiles a vast amount of literature that supports a pivotal role for inflammasomes in the various epithelial barriers of the human body as essential factors maintaining immune signaling and homeostasis . |
familial amyloid polyneuropathy ( fap ) is an inherited disorder with autosomal dominant transmission , characterized by systemic extracellular accumulation of amyloid fibrils .
the most common type of fap is related to transthyretin ( ttr ) , a protein that carries thyroxine and vitamin a .
plasma - circulating ttr is mainly synthesized in the liver , but there is also production in the retinal pigment epithelium and in the choroid plexus [ 3 , 4 ] .
the clinical expression is variable among different mutations and different populations , and even the same population with the same mutation can present significant variability .
the peripheral nerves and the heart are the organs most frequently affected . more than 100 mutations have been related to fap , but one point mutation in which a methionine residue replaces the valine residue at position 30 ( ttr val30met ) is particularly frequent and is associated with several large foci around the world , namely portugal , japan , sweden and the balearic islands [ 6 , 7 , 8 , 9 ] . this condition was first described in portugal in 1952 , when andrade reported a peculiar neuropathy characterized by ascending sensory - motor loss and severe autonomic dysfunction , affecting patients of both genders between 25 and 35 years of age .
vitreous involvement was mentioned for the first time by kantarjian and dejong in 1953 in two siblings with fap .
the first description of the swedish focus in 1968 also reported the occurrence of vitreous opacities along with the typical sensory , motor and autonomic neuropathy with onset at a later age if compared with portuguese and japanese patients . in portugal ,
vitreous opacities have rarely been described in patients with the natural and fatal course of the disease , but the prolonged survival after liver transplant led to a significant increase in the prevalence of this problem [ 14 , 15 ] .
ocular manifestations of fap include abnormal conjunctival vessels , keratoconjunctivitis sicca , irregularities on lens surface and border of the pupil , change of pupillary shape and light reflex , vitreous opacities and glaucoma [ 16 , 17 ] .
vitreous deposits of amyloid may be seen as one manifestation among other signs of the disease , but it has also been described as the earliest , isolated symptom of the disease [ 18 , 19 , 20 ] .
we report a case of vitreous opacities as the initial manifestation of fap ttr val30met in a late - onset portuguese patient without a history of fap .
an apparently healthy 66-year - old man , born in santa maria da feira and resident in vila nova de gaia , portugal , was first examined in march 2010 for right blurred vision and floaters .
best - corrected visual acuity was 20/30 in the right eye and 20/20 in the left eye .
the anterior segment of both eyes was unremarkable , with no abnormal conjunctival vessels , no change of pupillary shape , and no amyloid deposition at pupillary border or lens surface .
vitreous yellowish - white opacities precluding examination of the fundus were identified in the right eye .
full clinical evaluation showed an asymptomatic first - degree atrioventricular ( av ) block in the absence of other neurologic or cardiac signs of disease .
the mutation ttr val30met was identified by full sequencing of the gene , and a salivary gland biopsy was done but failed to show amyloid deposition . in november 2010 , as the right visual acuity dropped to 20/100 the patient underwent a pars plana vitrectomy .
the pathological examination of the surgical specimen which included congo red stain showed material with yellowish - green birefringence consistent with amyloid .
a mobitz 2 second - degree av block was demonstrated with a holter register and he was submitted to a pacemaker implantation , with complete recovery of these symptoms . in september 2012 ,
the right eye developed a cataract and the left eye presented vitreous opacities ( fig .
1 ) . at that time , the light pupillary reflex and the pupil shape were normal .
biomicroscopy of both eyes revealed no amyloid deposits on the lens surface or at the pupillary border .
he was submitted to a phacoemulsification of the cataract with intraocular lens implantation in the right eye in september 2012 .
one month later , pars plana vitrectomy was performed in the left eye without complications ( fig .
his best - correct visual acuity of both eyes was 20/20 , and the ophthalmological examination was normal , except for pseudophakia of the right eye .
nine siblings ( 1 brother , 1 sister and 7 half - brothers and half - sisters ) , 3 sons and 7 grandsons had no symptoms suggesting onset of the disease up to the time of reporting ( fig .
fap is a heterogeneous disease characterized by systemic accumulation of mutant amyloidogenic ttr in different tissues , including the eye .
portugal is the largest focus of the disease in the world , and it is related almost exclusively to the same mutation , ttr val30met .
the age of onset shows a wide range ( from 17 to 78 years ) , but 87% of patients developed symptoms before 40 years of age ( mean 33.5 years of age ) .
ocular manifestations commonly reported in fap patients are abnormal conjunctival vessels , keratoconjunctivitis sicca , pupillary abnormalities , glaucoma and vitreous opacity . in a study with 37 japanese patients , abnormal conjunctival vessels had the highest incidence with 100% after 10 years of follow - up , followed by the other abnormalities , with vitreous opacities reaching 17% in the same follow - up .
it was also demonstrated that ocular manifestations increase with time [ 16 , 21 ] . however , our patient had no other ocular manifestation except vitreous opacities , which are , when numerous , pathognomonic of the disease . in portuguese fap patients ,
vitreous opacities usually occur years after neurologic manifestations and are associated with other ocular changes , such as pupillary abnormalities .
vitreous amyloid deposits are one of the main causes of decreased visual acuity in fap patients .
although there are some reports describing isolated vitreous opacities , to the best of our knowledge , this is the first description of a similar case in a portuguese patient .
at least 20 mutations of ttr have been related to vitreous deposits , including ttr val30met , ttr tyr114cys , ttr phe33val , ttr ile84ser and ttr ile84asp . in a report of swedish homozygous
the only mutation identified in patients with vitreous opacities was ttr val30met , as in our patient .
ideally , treatment of vitreous amyloidosis should remove the existing amyloid fibrils and prevent further amyloid deposition .
vitrectomy , which can be diagnostic and therapeutic , is a safe and effective surgical treatment done when a significant visual morbidity is present .
the recurrence of vitreous opacities after vitrectomy has been described in some series [ 24 , 25 ] .
this should be prevented with an extraction , as complete as possible , of vitreous , particularly behind the posterior capsule of lens .
suggest performing phacoemulsification and intraocular lens implantation because more extensive removal of the vitreous base is possible with lens removal .
it is known that ttr , the precursor protein of amyloid , is predominantly synthesized by the liver .
primarily , it has been suggested that amyloid deposits in the vitreous because ttr can cross the blood - aqueous barrier . however , there is evidence of ttr synthesis in the retinal pigment epithelium of the eye , and it has been proposed that vitreous amyloid deposition is the result of the local synthesis of the mutated ttr . in a study of kawaji
, it is suggested that ciliary pigment epithelium may also synthesize ttr in addition to the retinal pigment epithelium .
the frequent occurrence of ocular amyloid deposition after liver transplantation confirms the importance of persistent local synthesis of mutated ttr .
patients with the val30met mutation usually present sensory - dominant polyneuropathy ( more commonly in lower limbs ) , autonomic disturbances and cardiac dysfunction . in the present case ,
an av block needing a pacemaker implantation was the only systemic manifestation during the follow - up .
this means the vitreous amyloid can be a signal of a potential severe systemic disease despite an absence of systemic manifestations , demonstrating the importance of being alert to the whole system .
this unusual presentation should not preclude the diagnosis because vitreous opacities are pathognomonic of amyloidosis . in conclusion
, the ophthalmologist can have an important role as the first physician detecting typical manifestations of the disease .
ocular manifestations such as vitreous opacities and glaucoma lead to visual impairment and can potentially be addressed by surgery .
an accurate and frequent follow - up evaluation is needed for the detection of ocular manifestations to ensure a good vision and quality of life of fap patients .
| familial amyloid polyneuropathy ( fap ) is a group of disorders characterized by the extracellular deposition of amyloid substance in various tissues . the peripheral nervous system and the heart are the main target organs , but the eye may also be involved .
we report a case of vitreous amyloidosis as the first manifestation of fap in a 66-year - old portuguese man without a family history . |
a 53-years - old iraqi immigrant with longstanding ulcer history complained of severe epigastric pain .
minimal biliary dilatation was identified , with normal gallbladder , intrahepatic ductal air [ figure 1a ] , adhesion between the ventral pancreatic head and posterior proximal duodenum [ figure 1b ] , thin fluid - like track suggesting choledocho - duodenal fistula ( cdf ) [ figure 1c ] .
unenhanced images detect peripheral intrahepatic pneumobilia ( arrowhead in a ) , overdistended stomach , and focal adhesion between posterior wall of the proximal duodenum and ventral aspect of the pancreatic head ( thick arrow in b ) .
after intravenous contrast administration , detailed oblique - reformatted image ( c ) shows thin fluid - like communication consistent with choledocho - duodenal fistula ( arrow ) .
three days later , during acute pancreatitis repeat ct ( d ) detects appearance of peripancreatic effusion , confirms fluid - containing fistulous track between the posterior duodenal bulb and the distal common bile duct ( thin arrow ) endoscopy revealed chronic peptic duodenal bulb deformation without active ulcers and fistulous orifices .
after unsuccessful endoscopic retrograde cholangiopancreatography ( ercp ) , clinical conditions worsened with acute pancreatitis . repeat ct detected peripancreatic fluid , increasing pneumobilia , persistent cdf [ figure 1d ] .
spontaneous pneumobilia suggests bilioenteric communication , most usually cholelithiasis - related gallbladder perforation into normal duodenum .
conversely , the uncommon ( 3.5 - 10% of cases ) cdf results from bulb ulcer penetrating the choledochus.[15 ] reflecting distribution of peptic disease , cdf manifests with pain , malaise or hematemesis in middle - aged men ; jaundice or cholangitis are exceptional . historically , duodenal deformity and biliary opacification during gastrointestinal barium studies identified cdf .
conversely , gallbladder mural thickening and intraluminal air shift the diagnosis toward cholecysto - duodenal fistulization . often impossible because of duodenal narrowing | spontaneous pneumobilia without previous surgery or interventional procedures indicates an abnormal biliary - enteric communication , most usually a cholelithiasis - related gallbladder perforation .
conversely , choledocho - duodenal fistulisation ( cdf ) from duodenal bulb ulcer is currently exceptional , reflecting the low prevalence of peptic disease .
combination of clinical data ( occurrence in middle - aged males , ulcer history , absent jaundice and cholangitis ) and ct findings including pneumobilia , normal gallbladder , adhesion with fistulous track between posterior duodenum and pancreatic head ) allow diagnosis of cdf , and differentiation from usual gallstone - related biliary fistulas requiring surgery .
conversely , ulcer - related cdf are effectively treated medically , whereas surgery is reserved for poorly controlled symptoms or major complications . |
in the 1990s , polly matzinger introduced the concept of immunological danger as a further refinement of burnet s original clonal selection theory which is the basis of self nonself discrimination by the immune system ( fuchs and matzinger 1996 ) . in her danger concept of immune function , she proposed immune responses result from detecting and addressing danger and not just nonself . in this context , the molecules associated with distress and damage ( including self molecules ) are regarded as the prime stimuli for immunological reactivity .
self - danger signals were postulated to originate from , for instance , necrotic cells that succumb to infection or ischemia .
danger-associated molecule ( damps ) functions , such as high - mobility group box-1 ( hmgb1 ) protein , the most abundant member of the hmg family of dna - binding proteins . other candidates
include cytosolic calcium - binding proteins of the s-100 family , nucleosomes , uric acid , and antibacterial peptides ( harris and raucci 2006 ) .
it was logical and attractive to incorporate into this concept families of heat shock proteins ( hsps ) as they are upregulated during stressful cellular events such as in tissue necrosis .
hsps have since often been categorized as prototypic danger associated molecular patterns or damps .
as a brief aside , the terminology in this field exemplifies the continuing maturation of the danger concept since its original inception .
the term damps is given in analogy with the earlier coined pamps ( pathogen - associated molecular patterns ) , which were proposed to be structures recognized by so - called pattern recognition receptors . at this moment , however , damps is more known as damage-associated molecular patterns .
the latter was proposed for the situation in clinical organ transplantation , where the transplant does not reflect a danger but rather a benefit to the recipient .
the upregulated hsps resulting from reperfusion injury were therefore viewed as a typical damp in the sense of damage and not danger - associated molecular pattern ( land 2005 ) . in the more narrow definition
they are released during necrotic and not apoptotic cell death , after which the innate immune system responds both directly with inflammation and indirectly by recruiting reinforcements from the adaptive immune system ( kono and rock 2008 ) .
kono and rock have attempted to outline four criteria in terms of biological outcomes that must be fulfilled for a molecule to be classified as a damp ( kono and rock 2008):a damp should be active as a highly purified moleculethe biological effect should not be owing to contamination with microbial molecules .
caution is particularly warranted if the putative damp is found to work through receptors for pamps such as toll - like receptors ( tlrs).the damp should be active at concentrations present in pathophysiological situationsselective elimination or inactivation of the damp should ideally inhibit the biological activity of dead cells in in vitro or in vivo assays .
a damp should be active as a highly purified molecule the biological effect should not be owing to contamination with microbial molecules .
caution is particularly warranted if the putative damp is found to work through receptors for pamps such as toll - like receptors ( tlrs ) .
the damp should be active at concentrations present in pathophysiological situations selective elimination or inactivation of the damp should ideally inhibit the biological activity of dead cells in in vitro or in vivo assays . in the case of hsps ,
the first two criteria are already problematic . given their chaperone nature , hsps readily engage other molecular structures , and experience has taught us that recombinant hsps are easily contaminated with microbial products when produced in microbial expression systems .
criterion 4 , by the authors own admission , is an ideal effect , and in most cases , this criterion is not fulfilled .
to put it bluntly , it seems questionable whether or not there exists any single damp which meets all of these criteria .
our brief analysis of the current literature on damps suggested that convincing evidence for single damp molecules initiating pro - inflammatory responses , as proven by the above criteria , may be lacking so far .
hsp60 was already known as the common antigen of gram - negative bacteria before the actual recognition of its molecular identity .
immunization with gram - negative bacteria led to the production of high levels of antibodies specific for this common antigen ( thole et al .
1985 ) , kaufmann and others have performed immunization studies with mycobacteria and with recombinant mycobacterial hsp60 demonstrating the resulting frequency of hsp60-specific t cells can be very high .
after immunization with mycobacterium tuberculosis , approximately one out of five of the m. tuberculosis - reactive t cells recognizes hsp60 .
immunization with recombinant hsp60 in an adjuvant also stimulated an impressively high number of m. tuberculosis - reactive t cells ( 1 out of 2,000 ) ( kaufmann et al .
, many others have shown the dominant immunogenicity of microbial hsps ( zugel and kaufmann 1999 ) .
given the conserved nature of hsps , this high level of immunogenicity is not immediately understood .
one would predict a low degree of immunogenicity for molecules having extensive sequence similarities with self antigens .
a healthy immune system is not supposed to respond to self antigens or their closely related homologs .
paradoxically , when mapping t cell epitopes for mycobacterial hsp60 in lewis rats , defined epitopes included many conserved sequences , and the responding t cells were found to cross - respond to homologous self - peptide derived from mammalian hsp60 ( anderton et al .
since then , self - hsp cross - reactive t cells have been identified in many models and even in human cord blood ( durai et al .
arthritis , their strongest t cell responses to self - hsp60 were detected in patients during remitting phases of their disease , suggestive of an anti - inflammatory mechanism resulting from self - hsp - directed t cell reactivity ( de graeff - meeder et al .
similar patterns of autoantibodies are observed for self - hsp70 , for example in diabetes and atherosclerosis ( abulafia - lapid et al .
interestingly , antigen microarray analysis for multiple sclerosis ( ms ) patients revealed that hsp70 autoantibodies were a characteristic antibody signature of patients with a remitting and relapsing form of the disease .
these antibodies were much less abundant in patients with progressive forms of ms , again associating hsp70 immune reactivity with disease remission ( quintana et al .
there are no reports of peculiar pro - inflammatory isotype ( e.g. , igg2a ) profiles for hsp - binding antibodies in patients with autoimmune diseases . and as an aside , direct polyclonal stimulation of mouse b cells with human hsp60 induced production of igg3 .
these activated b cells were also found to stimulate a th0 profile in t cells as opposed to a typical th1 , as indicated by their production of interleukin ( il)-10 and interferon gamma ( inf- ; cohen - sfady et al .
in addition , t cells reactive to hsps that have been reported were typically not pro - inflammatory , regardless of whether they were stimulated with mammalian ( self ) hsp or microbial hsps . in stark contrast ,
many antibodies or responding t cells were found to have anti - inflammatory activities ( moudgil et al .
these were demonstrated by their abilities to suppress an inflammatory disease or to produce anti - inflammatory cytokines such as il-10 ( prakken et al .
in other words , despite the fact that responses to hsps may be of fundamental interest to the immune system , the phenotypic characteristic of hsp immune reactivity does not reflect a typical damp - associated pro - inflammatory response .
be that as it may , one can not exclude that the dominant immunogenicity of hsp stems from their interaction with tlrs or other innate receptors .
however , there remain other possibilities which may explain the potent immunogenicity of hsps equally well ( table 1 ) .
the symbiotic relationship between the gut and intestinal microbiota ensures the regular immunological surveillance of our resident flora .
be it benign colonization by commensals or true invasion by pathogens , it will impose stress on every intruder , which will lead to an upregulation of microbial hsp and provide ample and repetitive opportunity for our immune system to respond to hsp . and logically , the immune response would most frequently encounter the most conserved epitopes . in this response ,
the expansion of t cells specific for conserved epitopes increases the likelihood of cross - reactivity with self - hsp . secondly , given their chaperone activities ,
an alternative explanation is that hsps are hitchhiking with other antigens for uptake and processing by antigen - presenting cells . in this manner
a third possibility is that hsps have an organized priority status for the immune system .
cohen has argued that hsps are examples of immune - privileged antigens , so - called homunculus antigens .
this would imply that the reactivity to such molecules is a genetically determined inherent quality of the immune system ( cohen 2007 ) .
thus , there are more ways to explain the exceptional immunogenicity of hsp , which do not depend on immediate interaction with tlrs or other receptors of the innate immune system . in conclusion , although the high immunogenicity may suggest innate receptors to be involved , there are ample alternative options to explain this aspect of hsp.table 1mechanisms leading to the hsp immunodominancerepeated contact leads to a focus on conserved regionshitchhiking in the antigen uptake and processing machinerybuilt - in feature of the immune system ( homunculus idea)triggering of innate tlr receptors ? mechanisms leading to the hsp immunodominance a primary feature of chaperones
when peptide - loaded hsp70 is delivered to dendritic cells ( dcs ) , the peptide is rerouted through the major histocompatibility complex ( mhc ) class i pathway antigen presentation , via cross - presentation , for display to cd8 cytotoxic t cells ( rock and shen 2005 ) . in a number of studies on cross - presentation by hsp
, evidence was provided for a stimulatory effect on dc maturation and activation ( binder 2009 ) . with respect to accompanying dc maturation
, controversy has arisen regarding the role of microbial contaminants in this dc stimulatory effect as some authors have presented evidence that lipopolysaccharide ( lps ; tlr4 ) , lipoprotein ( tlr2 ) , or flagellin ( tlr5 ) were the active compounds here ( tsan and gao 2009 ) . in one study , purposeful removal of contaminating lps did not prevent peptide presentation , but did abrogate activation of human dcs in association with human hsp70 ( bausinger et al .
, peptides fused to hsp60 also induced cd8 cytotoxic t cells ( cho et al .
this fusion product was stimulatory to dcs , leading to upregulation of mhc ( class i and ii ) and co - stimulatory molecules ( b7.2 ) , whereas unexpectedly hsp60 alone was not stimulatory .
thus , although cross - presentation mediated by hsp seems real , the dc stimulating activities may be uncertain , to say the least . a balanced review
which , overall , argues against endotoxin being the active ingredient in many hsp effects is however henderson et al .
damps are generally regarded as being intracellular proteins that are hidden from recognition by the immune system until exposed by cell damage , such as necrosis .
several receptors are purported to mediate damp recognition ( e.g. , receptor for advanced glycation end products ( rage ) and tlr9 ) and subsequently propagate an inflammatory response .
additionally , the supposed danger qualities of hsp are proposed to be mediated through receptor - mediated endocytosis ( arnold - schild et al .
there is now a general consensus that the interactions of tlrs with pamps evolved to prepare the immune system for tailor - made responses to invading microbes . a diversity of tlrs ( and also rigs , nod , etc .
) enables the immune system to be discriminative at the early level of innate defenses .
a microbe that activates tlr4 and tlr5 is likely to be a flagellated gram - negative bacterium , while a microbe that triggers tlr2 , 5 , and 6 qualifies to be a flagellated gram - positive bacterium .
very aptly , this was called the barcode model of immune recognition ( aderem 2003 )
which advantageous aspect would hsps serving as damps offer to this system ? what would have been the evolutionary advantage of having hsp as a damp included in such a recognition strategy ?
a direct innate response to proteins released by necrotic cells , unidirectionally activating a pro - inflammatory response , would disturb the bar coding
a feature of tlrs which still remains to be fully appreciated is that they generate not only pro - inflammatory responses but also suppressive responses in innate immune cells ( conroy et al .
tlr2 for example has been shown to be present on treg cells , and its triggering by an hsp60-derived peptide led to cytokine and contact - dependent suppression ( zanin - zhorov et al .
in addition , il-10-producing t cells were generated in vivo through tlr2 triggering by capsular polysaccharides of commensal bacteria ( round and mazmanian 2010 ) .
tlr4 triggering by lps was seen to enhance survival and proliferation of treg cells ( caramalho et al . 2003 ) .
the effect of their triggering is therefore most likely cell - type specific and may depend very much on the context of their triggering , other factors released by other cells in the vicinity , and other receptors triggered simultaneously .
in other words , the integration of multiple signals must finally converge within a particular cell to drive the biological outcome .
given the examples of suppressive effects by hsp - derived peptides in this context , it seems even possible that hsps are dampening inflammatory signals through these innate receptors .
the search for dedicated heat shock protein receptors has been intensive over the past years .
we are left with a broad array of receptors with rather promiscuous binding characteristics . of the scavenger receptors ,
heat shock proteins are now known to interact with sra-1 , srec-1 , lox-1 , and feel-1 ( calderwood et al .
interestingly , some of these receptors were found to be immunosuppressive , such as sra-1 ( wang et al .
as put forth by calderwood : discerning the signaling networks emanating from such an array of receptors will be challenging ; however , this is essential if sense is to be made of the heat shock protein signal input ( reported in ( henderson et al .
whatever the outcome of such an exploration will be , a simply straightforward monotonous pro - inflammatory hsp response will be an unlikely outcome .
it is the result of modern cellular and molecular technologies that we tend to study single types of cells in their interactions with single defined molecules through tentative single receptors
. however , in reality , the complexity of immune behavior will not be visible by analyzing a linear sequence of consecutive events from cause to effect .
we will need a systems biology approach to integrate responses to hsp into a context - dependent unified systemic response .
a variety of molecules have been nominated to trigger innate receptors in a pro - inflammatory manner .
they are often presented as putative damps , despite the fact there may be no discernable patterns associated with their molecular structures . however , this is generally accepted as the name damp was coined in keeping with the pamps analogy of which the classical examples exhibit obvious molecular patterns . yet , hsps are not known to harbor any molecular patterns or to have any sequence or structural similarities between hsp of different families . possibly with an exception , if we accept the suggestion of hydrophobicity as a damage - associated molecular pattern . in that case
, hsp may have hydrophobic binding sites that are exposed in an atp - dependent manner to allow binding to hydrophobic parts of nascent or unfolded proteins ( seong and matzinger 2004 ) . possibly of more relevance to our discussion
therefore , the immune system does not seem to possess receptors that may distinguish the self from microbial . as a consequence ,
if self - hsps were damps , one would also expect the immunodominant microbial hsps to exert a continuous pro - inflammatory effect in our immune system : an unlikely and not very attractive situation .
damps typically reside intracellularly and are only exposed to the extracellular environment when cells undergo necrosis .
however , hsps are also exposed at the cell surface ( multhoff 2007 ) and exist as freely circulating hsp ( pockley and multhoff 2008 ) , and neither of these forms are easily compatible with damp - type pro - inflammatory activities of hsp .
some damps are claimed to exert their effects via a receptor associated with pro - inflammatory signaling .
antibody blocking of rage was seen to inhibit the ability of hmgb-1 to promote inflammation and was taken as proof that rage binds a pro - inflammatory hmbg-1 ( luan et al .
however , despite the fact that hmbg-1 may be taken as a prototypic damp , its role in directly promoting inflammation is also clouded in controversy ( bianchi 2007 ) .
in fact , the discussions here are similar to those concerning hsps as hmbg-1 can also complex with other molecules such as lps , and these associations are incriminated as the possible sources of the pro - inflammatory stimuli .
highly purified recombinant hmgb-1 was demonstrated to have a very weak direct pro - inflammatory activity at best ( rouhiainen et al .
, hmgb1 may need to form a complex with another component to activate inflammation by enhancing effects stimulated by a pamp , a damp , or a pro - inflammatory cytokine .
importantly , hmgb1 can bind avidly to immuno - stimulatory molecules such as lps , dna , or interleukin ( il)-1 and promote their activity in a synergistic fashion ( pisetsky et al . 2008 ) .
as mentioned , no specific or unique receptors are known for hsps . and the most credited tlr receptors are not strictly pro - inflammatory .
interestingly , tlr2 and tlr4 , which are possibly the primary receptors for hsp60 and hsp70 , were found not to be essential in the host response to damps derived from necrotic cells ( chen and nunez 2010 ) .
most relevant in this discussion are the results of experiments in which dcs were cultured in the presence of hsps . for self - hsp , there is a lack of compelling evidence that hsp can directly activate dendritic cells , which are expected to express the whole panoply of damp receptors . when exorbitant concentrations ( 200300 g / ml ) of self - hsp70 ( purified from mouse liver using standard protocols under sterile conditions and with endotoxin - free reagents ) were applied , no stimulatory effects on murine dcs were observed ( wallin et al .
, the same authors have seen responses to low concentrations ( 50100 ng / ml ) of the same liver - derived hsp70 contaminated with minute amounts of endotoxin .
given the role of dendritic cells as key initiators of the immune response and their ability to give direction to the ensuing adaptive response , one may wish to see full activation of dcs for a pro - inflammatory adaptive immune response reaction . in even more careful analyses , human hsp70 has shown a lack of direct human dc activation qualities ( bendz et al .
2006 ) , even mycobacterial hsp70 exhibited an absence of activation ( no calcium signaling ) of human dcs ( bendz et al .
, the group of bonorino has shown that highly purified mycobacterial hsp70 impaired the maturation of murine bone marrow - derived dcs , leading to inhibition of t cell proliferation ( motta et al .
finally , hsps seem to exert immune - dampening effects in model systems , as we will discuss in the following section ( table 2).table 2features of hsps which disqualify them as dampsabsence of molecular patternsmain receptors tlr2 and tlr4 are not always pro - inflammatorytlr2 and tlr4 are not needed for signaling by damps from necrotic cellssome hsp receptors are downregulating inflammatory signalinghsp - incubated dcs adopt a tolerogenic phenotypehsp immunizations are anti - inflammatory features of hsps which disqualify them as damps initial studies of the immunological effect of hsp were carried out with recombinant mycobacterial hsp60 in the rat model of adjuvant arthritis .
hsp60 immunizations were found to inhibit disease development in this t cell - mediated autoimmune disease model ( van eden et al .
this disease ameliorative effect was t cell mediated since transfer of hsp60-specific t cells into nave recipients also imparted protection against arthritis in the recipients . by analyzing the exact antigen specificity of the protective t cells
, it was discovered that disease suppression was mediated by t cells that responded to a particularly conserved hsp60 sequence .
this sequence was so conserved that these t cells cross - recognized the homologous sequence present in the mammalian hsp60 molecule .
immunization with a synthetic peptide comprising this protective t cell epitope induced a fully protective t cell response against arthritis ( anderton et al .
cytokine analyses of the protective t cells demonstrated their capacity to produce suppressive cytokines such as il-10 ( prakken et al .
, similar protective effects have been shown for microbial hsps , including members of the hsp70 family , in various experimental models of autoimmunity ( summarized in ( van eden et al .
further demonstrated the immunosuppressive potential of mycobacterial hsp70 in two allograft survival models , an allogeneic melanoma and a regular allogeneic skin graft . very interestingly ,
rejection was inhibited by hsp70 incubation of the melanoma cells or the skin prior to grafting .
concurrent injection of an anti - cd25 antibody removed treg cells and fully abolished the rejection inhibitory effect ( borges et al .
mycobacterium which is known to have such strong immune - potentiating effects ! in some studies , immunizations with mammalian hsp have also been shown to inhibit disease .
this was done in arthritis for hsp60 ( paul et al . 2000 ) and hsp70 ( chandawarkar et al . 2004 ; corrigall et al . 2001 ; wendling et al . 2000 ) and in diabetes with an hsp60-derived peptide ( bockova et al .
1997 ) . in in vitro studies , gp96 ( glucose - regulated protein 94 ) , a member of the hsp90 family of stress proteins , was seen to have no effect on bone marrow - derived dendritic cells , but at a higher dose led to an increased il-10/inf- ratio in t cells .
this skewing also indicated the induction of a regulatory mode in t cells and was shown to induce a state of t cell hyporesponsiveness and delay the rejection of cardiac allografts in rats ( mirza et al .
more recently , we have shown that endogenous upregulation of hsp by hsp co - inducing compounds may also lead to the induction of hsp - specific treg cells . in the mouse model of proteoglycan - induced arthritis , we have shown that oral administration of oregano - derived carvacrol led to the upregulation of hsp70 in gut peyer s patches and draining lymph nodes and to the suppression of disease development .
moreover , the t cells responding to oral carvacrol treatment were shown to be cd4cd25foxp3 in the spleen and in the joint , indicating that the disease suppression was mediated by the induction of genuine treg cells ( wieten et al .
a similar effect may have occurred in the case of triptolide - induced hsp70 expression , which may have yielded the protective effect in eae models for multiple sclerosis ( van eden 2009 ) .
genetic evidence for a disease suppressive role of endogenous hsp70 was obtained in a transgenic mouse model of dextran sulfate sodium - induced colitis . reduced
disease and less pro - inflammatory cytokine production were seen in hsp70-overexpressing animals . in hsf-1
null mice , the opposite phenotype was observed , as disease worsened and more pro - inflammatory cytokines were produced ( tanaka et al .
a similar study showed the disease suppressive role of hsp70 in bleomycin - induced pulmonary fibrosis ( tanaka et al .
introduced the idea of certain hsp molecules acting as resolution - associated molecular patterns or ramps .
ramps were proposed to exert immunological activity by restoring immune homeostasis by deactivating cells of the innate immune system and by expanding regulatory cells ( shields et al .
while they accept the idea that most hsp will act as damps , they propose some hsp molecules ( hsp10 , hsp27 , alpha b - crystallin , and bip or grp78 ) to be exceptional and to act as ramps . in our opinion , the examples they cite have effects similar to those seen for members of major hsp families such as hsp60 and hsp70 .
hsp10 was formerly known as the early pregnancy factor and had an immune regulatory role in preventing of rejection of the allogeneic embryo .
since then , hsp10 was found to have immune regulatory effects in various other systems : serum levels were found to correlate with t cell receptor down - modulation ( cd3 expression ) , proliferation of jurkat t cell lines was inhibited , and in vitro , hsp10 pretreatment inhibited lps - stimulated tnf- and il-6 secretion by human peripheral blood mononuclear cells ( johnson et al . 2005 ) .
recombinant hsp27 has a tendency to induce il-10 secretion in cultured human monocytes , and it blocks differentiation of monocytes to dendritic cells ( de et al . 2000 ; laudanski et al .
the hsp70 family member bip was found to downregulate mhc and the co - stimulatory molecule cd86 .
instead , it stimulated production of anti - inflammatory cytokines il-1 receptor antagonist , soluble tnf receptor ii , and il-10 ( corrigall et al . 2004 ) .
additional immunosuppressive effects of hsp have also been seen in the case of exosome - associated hsp70 .
membrane - associated hsp72 obtained from tumor - derived exosomes were observed to mediate a suppressive activity in myeloid - derived suppressor cells .
possibly , this is one mechanism by which tumor immune surveillance is restrained ( chalmin et al .
the possible further complexity of hsp - associated cellular export vesicles and cellular communications under stress conditions and its potential implications have already been discussed in an authoritative manner by de maio in an earlier perspective and reflection article ( de maio 2011 ) . if we refute the possibility that hsp are damps , and we recognize the prominent role of hsp in cognate interactions with the immune system , we are confronted with the question of what the actual immunological significance of hsp may be .
the elevated levels of hsp in inflamed , traumatized , or reperfused tissues in combination with the extensive immune repertoire of cells with the capacity to recognize hsp indicate that these proteins may be biomarkers of damage , providing targets for immune mechanisms involved in restoration of tissue and immune homeostasis . with the recent rediscovery of regulatory t cells ( treg ) , the role of the immune system in homeostasis has received renewed interest . also the reinterpretation of self / nonself discrimination , as was revamped by the danger
concept , seems to have boosted our appreciation of mechanisms of immune homeostasis . currently , there is a flurry of interest in the host
the immune system can not tolerate becoming rampantly stimulated by foreign molecules , but has to figure out whether a certain stimulus is just microbial nonself or a signal of imminent danger . in the case of benign microbial nonself as present in our enteric microbiota , a carefully regulated response suffices or is even imperative .
it is in this relationship that a major role for treg cells is proposed . despite many technical obstacles ,
it is now widely accepted that treg cells do exist and can suppress immune responses in an antigen - specific manner , also in areas other than the gut .
natural treg cells are represented by a specialized subset of cd4dc25foxp3 t cells that are selected in the thymus on the basis of relatively high affinity self - recognition .
these cd4 t cells , which are also mostly cd25foxp3 , are programmed in the peripheral lymphoid organs or in the tissues to adopt a regulatory status .
notably , hsps are abundantly expressed in the thymus in the areas where positive selection of t cells takes place ( anderson et al .
therefore , hsp - specific natural treg cells may be selected in the thymus , whereas hsp - specific induced treg cells may originate from elevated hsp expression in stressed peripheral tissues . besides their prominent role in the maintenance of immune homeostasis in relation to symbiotic interactions with the gut microbiota ,
treg cells are implicated in the anti - inflammatory responses that are seen in autoimmunity , cancer , and infection ( vignali et al .
, treg cells help to resolve the pro - inflammatory response , thereby reducing bystander damage .
in addition , treg cells may be even more fundamental in the organization of the immune response .
for example , it has been shown that treg cells may function to aid in efficient cell entry into sites of infection ( lund et al .
, new evidence seems to have surfaced that hsp can be antigens that stimulate the activity of treg cells ( see also previous section ) . for several reasons , this latter possibility may be plausible and attractive .
every cell in the body harbors the full spectrum of hsp molecules . under stress , many of them are upregulated , and their fragments are processed and presented by mhc molecules on the cell surface .
some hsp70 family members ( hsc70 or hspa8 and in addition dnajb1 and hspc ) are involved in chaperone - mediated autophagy , a process whereby during stress or nutrient deprivation cytosolic proteins are reused by cells and are routed through a subcellular compartment that intersects with the mhc class ii route ( majeski and fred dice 2004 ) .
this means that , especially under stress , fragments of hsp70 may be loaded into mhc class ii products .
herewith hsp70 epitopes are being presented in a preferential manner to cd4 t cells , which includes tregs . based on other arguments , such as the autophagy - mediated disposition of proteins with a long half - life and mhc binding predictions ,
hsp70 has already been proposed as an important source of peptides to be loaded onto mhc class ii molecules , also in the absence of stress ( paludan et al .
a mass spectroscopy analysis of peptides eluted from mhc class ii obtained from stressed human b cells , revealed that hsp70 ( hspa1a , hspa6 , and hspa8 ) fragments composed a major portion of the bound collection of peptides ( dengjel et al .
thus , the immune system , including treg cells , has ample opportunity to encounter mhc - presented hsp epitopes , and this will be especially prevalent during inflammation or other stress conditions .
for treg cell - mediated immune homeostasis this situation may be ideal . when trying to imagine how antigen - specific treg cells could work , one has to realize that it is unlikely that effective regulation is secondary to the presence of a very small number of autoantigen - specific treg cells present in a polyclonal population .
as already pointed out by shevach , a more likely scenario is that polyclonal treg cells are able to exert control because they are being regularly activated through their tcr by complexes of mhc class ii and ubiquitous self - peptides ( shevach 2009 ) .
if so , hsps would provide an excellent collection of prominently expressed certainly under stress
figure 1 represents three typical scenarios : sterile tissue damage ( autoimmune inflammation , reperfusion injury , heat stress ) , true danger imposed by pathogen invasion ( infection ) , and commensalism / symbiosis ( e.g. , exposure to gut microbiota ) .
maintenance of tissue homeostasis is required in all these instances , and one may assume that the immune system is having a major role here .
given the postulated capacity of hsps to trigger treg cells , it seems attractive to attribute , at least in part , the restoration of tissue and immune homeostasis to the activity of hsp - specific treg cells.fig .
1the immune system will restore homeostasis when the latter is challenged by sterile damage , pathogens , or commensals . in all cases ,
hsps are present and even upregulated host responses are terminated by regulation . in the host response , the hsp can be the targets for the regulation , such as for the regulation exerted by treg cells the immune system will restore homeostasis when the latter is challenged by sterile damage , pathogens , or commensals . in all cases ,
hsps are present and even upregulated host responses are terminated by regulation . in the host response , the hsp can be the targets for the regulation , such as for the regulation exerted by treg cells there exist two ways by which heat shock proteins can interact with the immune system ( fig .
first of all , their intracellular upregulation as a consequence of cell stress will lead to upregulated mhc presentation of hsp fragments ( peptides ) at the cell surface making them visible to t cells .
secondly , they may be translocated by yet undefined mechanisms , as complete molecules to the cell surface or to the extracellular environment .
this would allow them to be encountered by nk cells , antibodies , and antigen - presenting cells .
besides active translocation , cell necrosis is probably a mechanism through which hsps are released into the extracellular environment .
it is safe to conclude that these two distinct contexts for hsp interactions with the immune system will lead to distinct immunological outcomes.fig .
the released hsp will be seen by receptors on antigen - presenting cells such as dc in combination with pamps .
it is possible that hsps do contribute to the pamp - elicited inflammatory response , thereby enhancing collateral tissue damage .
sterile inflammation will upregulate intracellular hsp in antigen - presenting cells such as dc which leads to the triggering of regulatory t cells that dampen inflammation extracellular hsps are released from necrotic cells when cells die from infection .
the released hsp will be seen by receptors on antigen - presenting cells such as dc in combination with pamps .
it is possible that hsps do contribute to the pamp - elicited inflammatory response , thereby enhancing collateral tissue damage .
sterile inflammation will upregulate intracellular hsp in antigen - presenting cells such as dc which leads to the triggering of regulatory t cells that dampen inflammation in principle , damp producing cell death is proposed to result mainly from necrosis . whether cell death is immunogenic , tolerogenic , or
2009 ) . activated apoptotic cells have adjuvant properties and induce expression of maturation markers ( cd80 , cd83 , and cd86 ) and secretion of pro - inflammatory cytokines in dcs ( johansson et al . 2007 ) .
in contrast to this , t cells that succumb to activation - induced cell death after clonal expansion promote tolerance by stimulating regulatory cd8 t cells ( herndon et al . 2005 ) .
thus , timing of cell death seems important : cell death at the peak of the immune response produces immune activation , whereas cell death during a waning immune response supports regulation .
most necrotic cells are considered to produce an immune response , but also here the cell type , the history of the cell , its mode of activation , and the manner of stress imposed on the cell may determine whether or not this form of cell death is immunogenic ( green et al . 2009 ) .
in other words , as long as we do not know exactly how to correlate the position of hsps with the type and circumstances of cell death , it will be hard to fully grasp the immunological role of hsp in cell death .
one of the problems that is associated with the immunogenicity of cell death is that cell death due to infection needs to be immunogenic , at least to some extent .
when dying cells would provide antigens , let us say hsp , that would lead to a firm tolerance or suppressive regulation , such tolerance or suppressive regulation would possibly include the microbial invader that led to cell death .
again , given the complexity of cell death immunogenicity , there may not be a simple one - dimensional role in cell death for hsp . in the case of cell death due to infection
, pamps may have an overriding effect driving a pro - inflammatory response , at least at the start of infection .
one can not exclude that extracellular hsps contribute a positive pro - inflammatory effect of pamp - activated cells , such as activated dcs by possibly amplifying their tlr signaling .
it is also possible that hsps form complexes with pamps to support pro - inflammatory activity by chaperoning the pamps involved or by synergistic effects . a similar discussion has been active with respect to hmgb-1 .
it was proposed that hmgb-1 released in the presence of tlr - binding pamps acted to promote inflammation , whereas hmgb-1 released in an environment devoid of pamps promoted tissue repair ( harris and raucci 2006 ) .
if this were the case , then it seems reasonable to assume a similar situation for hsp .
necrosis resulting from infection will lead to a pro - inflammatory response based on recognition of both pamps / damps and possibly hsps .
the ensuing elimination of the invaders would coincide with collateral damage . at this point ,
regulation in the form of active resolution , in part based on hsp recognizing treg cell , would kick - in and contribute to restoration of tissue homeostasis . from another point
, intracellular hsp would , besides their main task in safeguarding against intracellular protein misfolding under stress , find its way to the cell surface in the context of mhc molecules and trigger a presumably regulatory response at the level of t cells .
in addition , there may be still be the somewhat theoretical issue of active concentrations of hsp . at low , more or less constitutive concentrations , hsp may help to maintain immune homeostasis by promoting treg cell activities .
however , it is theoretically possible that relatively high concentrations of hsp that are liberated at sites of tissue damage or infection cause a loss of regulatory capacity and contribute to pro - inflammatory responses .
this would imply that when cellular stress decreases , resolution would set in and treg cells would become prominent responders when local hsp concentrations fall ( quintana and cohen 2011 ) .
irrespective of possible pro - inflammatory effects of supra - constitutive concentrations of hsp , under physiological conditions , a dampening effect on the immune system would prevail .
this may be very much in line with the recent successful clinical interventions in autoimmune inflammatory diseases based on the administration of hsp peptides ( albani et al .
hsp60 was already known as the common antigen of gram - negative bacteria before the actual recognition of its molecular identity .
immunization with gram - negative bacteria led to the production of high levels of antibodies specific for this common antigen ( thole et al .
1985 ) , kaufmann and others have performed immunization studies with mycobacteria and with recombinant mycobacterial hsp60 demonstrating the resulting frequency of hsp60-specific t cells can be very high . after immunization with mycobacterium tuberculosis ,
approximately one out of five of the m. tuberculosis - reactive t cells recognizes hsp60 .
immunization with recombinant hsp60 in an adjuvant also stimulated an impressively high number of m. tuberculosis - reactive t cells ( 1 out of 2,000 ) ( kaufmann et al .
, many others have shown the dominant immunogenicity of microbial hsps ( zugel and kaufmann 1999 ) . given the conserved nature of hsps
one would predict a low degree of immunogenicity for molecules having extensive sequence similarities with self antigens .
a healthy immune system is not supposed to respond to self antigens or their closely related homologs .
paradoxically , when mapping t cell epitopes for mycobacterial hsp60 in lewis rats , defined epitopes included many conserved sequences , and the responding t cells were found to cross - respond to homologous self - peptide derived from mammalian hsp60 ( anderton et al .
since then , self - hsp cross - reactive t cells have been identified in many models and even in human cord blood ( durai et al . 2004 ; paul et al . 2000 ) . in children suffering from juvenile idiopathic arthritis , their strongest t cell responses to self - hsp60 were detected in patients during remitting phases of their disease , suggestive of an anti - inflammatory mechanism resulting from self - hsp - directed t cell reactivity ( de graeff - meeder et al .
furthermore , autoantibodies against hsp have been found to be prevalent in healthy subjects . for hsp60 ,
similar patterns of autoantibodies are observed for self - hsp70 , for example in diabetes and atherosclerosis ( abulafia - lapid et al .
interestingly , antigen microarray analysis for multiple sclerosis ( ms ) patients revealed that hsp70 autoantibodies were a characteristic antibody signature of patients with a remitting and relapsing form of the disease .
these antibodies were much less abundant in patients with progressive forms of ms , again associating hsp70 immune reactivity with disease remission ( quintana et al .
there are no reports of peculiar pro - inflammatory isotype ( e.g. , igg2a ) profiles for hsp - binding antibodies in patients with autoimmune diseases . and as an aside , direct polyclonal stimulation of mouse b cells with human hsp60 induced production of igg3 .
these activated b cells were also found to stimulate a th0 profile in t cells as opposed to a typical th1 , as indicated by their production of interleukin ( il)-10 and interferon gamma ( inf- ; cohen - sfady et al .
in addition , t cells reactive to hsps that have been reported were typically not pro - inflammatory , regardless of whether they were stimulated with mammalian ( self ) hsp or microbial hsps .
in stark contrast , many antibodies or responding t cells were found to have anti - inflammatory activities ( moudgil et al .
these were demonstrated by their abilities to suppress an inflammatory disease or to produce anti - inflammatory cytokines such as il-10 ( prakken et al .
in other words , despite the fact that responses to hsps may be of fundamental interest to the immune system , the phenotypic characteristic of hsp immune reactivity does not reflect a typical damp - associated pro - inflammatory response . be that as it may
, one can not exclude that the dominant immunogenicity of hsp stems from their interaction with tlrs or other innate receptors .
however , there remain other possibilities which may explain the potent immunogenicity of hsps equally well ( table 1 ) .
the symbiotic relationship between the gut and intestinal microbiota ensures the regular immunological surveillance of our resident flora .
be it benign colonization by commensals or true invasion by pathogens , it will impose stress on every intruder , which will lead to an upregulation of microbial hsp and provide ample and repetitive opportunity for our immune system to respond to hsp . and logically , the immune response would most frequently encounter the most conserved epitopes . in this response ,
the expansion of t cells specific for conserved epitopes increases the likelihood of cross - reactivity with self - hsp . secondly , given their chaperone activities , an alternative explanation is that hsps are hitchhiking with other antigens for uptake and processing by antigen - presenting cells . in this manner
a third possibility is that hsps have an organized priority status for the immune system .
cohen has argued that hsps are examples of immune - privileged antigens , so - called homunculus antigens .
this would imply that the reactivity to such molecules is a genetically determined inherent quality of the immune system ( cohen 2007 ) .
thus , there are more ways to explain the exceptional immunogenicity of hsp , which do not depend on immediate interaction with tlrs or other receptors of the innate immune system . in conclusion , although the high immunogenicity may suggest innate receptors to be involved , there are ample alternative options to explain this aspect of hsp.table 1mechanisms leading to the hsp immunodominancerepeated contact leads to a focus on conserved regionshitchhiking in the antigen uptake and processing machinerybuilt - in feature of the immune system ( homunculus idea)triggering of innate tlr receptors ? mechanisms leading to the hsp immunodominance a primary feature of chaperones is their capacity to bind peptides .
when peptide - loaded hsp70 is delivered to dendritic cells ( dcs ) , the peptide is rerouted through the major histocompatibility complex ( mhc ) class i pathway antigen presentation , via cross - presentation , for display to cd8 cytotoxic t cells ( rock and shen 2005 ) . in a number of studies on cross - presentation by hsp
, evidence was provided for a stimulatory effect on dc maturation and activation ( binder 2009 ) . with respect to accompanying dc maturation
, controversy has arisen regarding the role of microbial contaminants in this dc stimulatory effect as some authors have presented evidence that lipopolysaccharide ( lps ; tlr4 ) , lipoprotein ( tlr2 ) , or flagellin ( tlr5 ) were the active compounds here ( tsan and gao 2009 ) . in one study , purposeful removal of contaminating lps did not prevent peptide presentation , but did abrogate activation of human dcs in association with human hsp70 ( bausinger et al .
2002 ) . in juxtaposition , peptides fused to hsp60 also induced cd8 cytotoxic t cells ( cho et al .
this fusion product was stimulatory to dcs , leading to upregulation of mhc ( class i and ii ) and co - stimulatory molecules ( b7.2 ) , whereas unexpectedly hsp60 alone was not stimulatory .
thus , although cross - presentation mediated by hsp seems real , the dc stimulating activities may be uncertain , to say the least . a balanced review which
, overall , argues against endotoxin being the active ingredient in many hsp effects is however henderson et al .
damps are generally regarded as being intracellular proteins that are hidden from recognition by the immune system until exposed by cell damage , such as necrosis . presumably , this release of damps into the extracellular fluid begins an inflammatory response .
several receptors are purported to mediate damp recognition ( e.g. , receptor for advanced glycation end products ( rage ) and tlr9 ) and subsequently propagate an inflammatory response .
additionally , the supposed danger qualities of hsp are proposed to be mediated through receptor - mediated endocytosis ( arnold - schild et al .
1999 ) . in the latter case tlrs , such as tlr2 and 4 , are again implicated as the dominating receptors ( vabulas et al .
there is now a general consensus that the interactions of tlrs with pamps evolved to prepare the immune system for tailor - made responses to invading microbes . a diversity of tlrs ( and also rigs , nod , etc . )
a microbe that activates tlr4 and tlr5 is likely to be a flagellated gram - negative bacterium , while a microbe that triggers tlr2 , 5 , and 6 qualifies to be a flagellated gram - positive bacterium .
very aptly , this was called the barcode model of immune recognition ( aderem 2003 ) .
which advantageous aspect would hsps serving as damps offer to this system ? what would have been the evolutionary advantage of having hsp as a damp included in such a recognition strategy ?
a direct innate response to proteins released by necrotic cells , unidirectionally activating a pro - inflammatory response , would disturb the bar coding
a feature of tlrs which still remains to be fully appreciated is that they generate not only pro - inflammatory responses but also suppressive responses in innate immune cells ( conroy et al .
tlr2 for example has been shown to be present on treg cells , and its triggering by an hsp60-derived peptide led to cytokine and contact - dependent suppression ( zanin - zhorov et al .
in addition , il-10-producing t cells were generated in vivo through tlr2 triggering by capsular polysaccharides of commensal bacteria ( round and mazmanian 2010 ) .
tlr4 triggering by lps was seen to enhance survival and proliferation of treg cells ( caramalho et al . 2003 ) .
the effect of their triggering is therefore most likely cell - type specific and may depend very much on the context of their triggering , other factors released by other cells in the vicinity , and other receptors triggered simultaneously .
in other words , the integration of multiple signals must finally converge within a particular cell to drive the biological outcome .
given the examples of suppressive effects by hsp - derived peptides in this context , it seems even possible that hsps are dampening inflammatory signals through these innate receptors .
the search for dedicated heat shock protein receptors has been intensive over the past years .
of the scavenger receptors , heat shock proteins are now known to interact with sra-1 , srec-1 , lox-1 , and feel-1 ( calderwood et al .
interestingly , some of these receptors were found to be immunosuppressive , such as sra-1 ( wang et al .
as put forth by calderwood : discerning the signaling networks emanating from such an array of receptors will be challenging ; however , this is essential if sense is to be made of the heat shock protein signal input ( reported in ( henderson et al .
whatever the outcome of such an exploration will be , a simply straightforward monotonous pro - inflammatory hsp response will be an unlikely outcome .
it is the result of modern cellular and molecular technologies that we tend to study single types of cells in their interactions with single defined molecules through tentative single receptors .
however , in reality , the complexity of immune behavior will not be visible by analyzing a linear sequence of consecutive events from cause to effect .
we will need a systems biology approach to integrate responses to hsp into a context - dependent unified systemic response .
a variety of molecules have been nominated to trigger innate receptors in a pro - inflammatory manner .
they are often presented as putative damps , despite the fact there may be no discernable patterns associated with their molecular structures . however , this is generally accepted as the name damp was coined in keeping with the pamps analogy of which the classical examples exhibit obvious molecular patterns . yet
, hsps are not known to harbor any molecular patterns or to have any sequence or structural similarities between hsp of different families . possibly with an exception , if we accept the suggestion of hydrophobicity as a damage - associated molecular pattern . in that case
, hsp may have hydrophobic binding sites that are exposed in an atp - dependent manner to allow binding to hydrophobic parts of nascent or unfolded proteins ( seong and matzinger 2004 ) .
possibly of more relevance to our discussion is the fact that there are no systematic differences between self and microbial hsp .
therefore , the immune system does not seem to possess receptors that may distinguish the self from microbial . as a consequence ,
if self - hsps were damps , one would also expect the immunodominant microbial hsps to exert a continuous pro - inflammatory effect in our immune system : an unlikely and not very attractive situation .
damps typically reside intracellularly and are only exposed to the extracellular environment when cells undergo necrosis .
however , hsps are also exposed at the cell surface ( multhoff 2007 ) and exist as freely circulating hsp ( pockley and multhoff 2008 ) , and neither of these forms are easily compatible with damp - type pro - inflammatory activities of hsp . some damps are claimed to exert their effects via a receptor associated with pro - inflammatory signaling .
antibody blocking of rage was seen to inhibit the ability of hmgb-1 to promote inflammation and was taken as proof that rage binds a pro - inflammatory hmbg-1 ( luan et al .
however , despite the fact that hmbg-1 may be taken as a prototypic damp , its role in directly promoting inflammation is also clouded in controversy ( bianchi 2007 ) .
in fact , the discussions here are similar to those concerning hsps as hmbg-1 can also complex with other molecules such as lps , and these associations are incriminated as the possible sources of the pro - inflammatory stimuli .
highly purified recombinant hmgb-1 was demonstrated to have a very weak direct pro - inflammatory activity at best ( rouhiainen et al .
, hmgb1 may need to form a complex with another component to activate inflammation by enhancing effects stimulated by a pamp , a damp , or a pro - inflammatory cytokine .
importantly , hmgb1 can bind avidly to immuno - stimulatory molecules such as lps , dna , or interleukin ( il)-1 and promote their activity in a synergistic fashion
as mentioned , no specific or unique receptors are known for hsps . and the most credited tlr receptors are not strictly pro - inflammatory .
interestingly , tlr2 and tlr4 , which are possibly the primary receptors for hsp60 and hsp70 , were found not to be essential in the host response to damps derived from necrotic cells ( chen and nunez 2010 ) .
most relevant in this discussion are the results of experiments in which dcs were cultured in the presence of hsps . for self - hsp , there is a lack of compelling evidence that hsp can directly activate dendritic cells , which are expected to express the whole panoply of damp receptors . when exorbitant concentrations ( 200300 g / ml ) of self - hsp70 ( purified from mouse liver using standard protocols under sterile conditions and with endotoxin - free reagents ) were applied , no stimulatory effects on murine dcs were observed ( wallin et al .
, the same authors have seen responses to low concentrations ( 50100 ng / ml ) of the same liver - derived hsp70 contaminated with minute amounts of endotoxin .
given the role of dendritic cells as key initiators of the immune response and their ability to give direction to the ensuing adaptive response , one may wish to see full activation of dcs for a pro - inflammatory adaptive immune response reaction . in even more careful analyses , human hsp70 has shown a lack of direct human dc activation qualities ( bendz et al .
2006 ) , even mycobacterial hsp70 exhibited an absence of activation ( no calcium signaling ) of human dcs ( bendz et al .
, the group of bonorino has shown that highly purified mycobacterial hsp70 impaired the maturation of murine bone marrow - derived dcs , leading to inhibition of t cell proliferation ( motta et al .
finally , hsps seem to exert immune - dampening effects in model systems , as we will discuss in the following section ( table 2).table 2features of hsps which disqualify them as dampsabsence of molecular patternsmain receptors tlr2 and tlr4 are not always pro - inflammatorytlr2 and tlr4 are not needed for signaling by damps from necrotic cellssome hsp receptors are downregulating inflammatory signalinghsp - incubated dcs adopt a tolerogenic phenotypehsp immunizations are anti - inflammatory features of hsps which disqualify them as damps
initial studies of the immunological effect of hsp were carried out with recombinant mycobacterial hsp60 in the rat model of adjuvant arthritis .
hsp60 immunizations were found to inhibit disease development in this t cell - mediated autoimmune disease model ( van eden et al .
this disease ameliorative effect was t cell mediated since transfer of hsp60-specific t cells into nave recipients also imparted protection against arthritis in the recipients . by analyzing the exact antigen specificity of the protective t cells
, it was discovered that disease suppression was mediated by t cells that responded to a particularly conserved hsp60 sequence .
this sequence was so conserved that these t cells cross - recognized the homologous sequence present in the mammalian hsp60 molecule .
immunization with a synthetic peptide comprising this protective t cell epitope induced a fully protective t cell response against arthritis ( anderton et al .
cytokine analyses of the protective t cells demonstrated their capacity to produce suppressive cytokines such as il-10 ( prakken et al .
, similar protective effects have been shown for microbial hsps , including members of the hsp70 family , in various experimental models of autoimmunity ( summarized in ( van eden et al .
further demonstrated the immunosuppressive potential of mycobacterial hsp70 in two allograft survival models , an allogeneic melanoma and a regular allogeneic skin graft . very interestingly ,
rejection was inhibited by hsp70 incubation of the melanoma cells or the skin prior to grafting .
concurrent injection of an anti - cd25 antibody removed treg cells and fully abolished the rejection inhibitory effect ( borges et al .
astonishing findings for a molecule derived from a microbe mycobacterium which is known to have such strong immune - potentiating effects ! in some studies , immunizations with mammalian hsp have also been shown to inhibit disease .
this was done in arthritis for hsp60 ( paul et al . 2000 ) and hsp70 ( chandawarkar et al . 2004 ; corrigall et al .
2001 ; wendling et al . 2000 ) and in diabetes with an hsp60-derived peptide ( bockova et al .
1997 ) . in in vitro studies , gp96 ( glucose - regulated protein 94 ) , a member of the hsp90 family of stress proteins , was seen to have no effect on bone marrow - derived dendritic cells , but at a higher dose led to an increased il-10/inf- ratio in t cells .
this skewing also indicated the induction of a regulatory mode in t cells and was shown to induce a state of t cell hyporesponsiveness and delay the rejection of cardiac allografts in rats ( mirza et al .
more recently , we have shown that endogenous upregulation of hsp by hsp co - inducing compounds may also lead to the induction of hsp - specific treg cells . in the mouse model of proteoglycan - induced arthritis , we have shown that oral administration of oregano - derived carvacrol led to the upregulation of hsp70 in gut peyer s patches and draining lymph nodes and to the suppression of disease development .
moreover , the t cells responding to oral carvacrol treatment were shown to be cd4cd25foxp3 in the spleen and in the joint , indicating that the disease suppression was mediated by the induction of genuine treg cells ( wieten et al .
a similar effect may have occurred in the case of triptolide - induced hsp70 expression , which may have yielded the protective effect in eae models for multiple sclerosis ( van eden 2009 ) . genetic evidence for a disease suppressive role of endogenous hsp70
reduced disease and less pro - inflammatory cytokine production were seen in hsp70-overexpressing animals . in hsf-1 null mice , the opposite phenotype was observed , as disease worsened and more pro - inflammatory cytokines were produced ( tanaka et al .
a similar study showed the disease suppressive role of hsp70 in bleomycin - induced pulmonary fibrosis ( tanaka et al .
introduced the idea of certain hsp molecules acting as resolution - associated molecular patterns or ramps .
ramps were proposed to exert immunological activity by restoring immune homeostasis by deactivating cells of the innate immune system and by expanding regulatory cells ( shields et al .
while they accept the idea that most hsp will act as damps , they propose some hsp molecules ( hsp10 , hsp27 , alpha b - crystallin , and bip or grp78 ) to be exceptional and to act as ramps . in our opinion , the examples they cite have effects similar to those seen for members of major hsp families such as hsp60 and hsp70 .
hsp10 was formerly known as the early pregnancy factor and had an immune regulatory role in preventing of rejection of the allogeneic embryo . since then
, hsp10 was found to have immune regulatory effects in various other systems : serum levels were found to correlate with t cell receptor down - modulation ( cd3 expression ) , proliferation of jurkat t cell lines was inhibited , and in vitro , hsp10 pretreatment inhibited lps - stimulated tnf- and il-6 secretion by human peripheral blood mononuclear cells ( johnson et al . 2005 ) .
recombinant hsp27 has a tendency to induce il-10 secretion in cultured human monocytes , and it blocks differentiation of monocytes to dendritic cells ( de et al . 2000 ; laudanski et al .
the hsp70 family member bip was found to downregulate mhc and the co - stimulatory molecule cd86 .
instead , it stimulated production of anti - inflammatory cytokines il-1 receptor antagonist , soluble tnf receptor ii , and il-10 ( corrigall et al . 2004 ) .
additional immunosuppressive effects of hsp have also been seen in the case of exosome - associated hsp70 .
membrane - associated hsp72 obtained from tumor - derived exosomes were observed to mediate a suppressive activity in myeloid - derived suppressor cells .
possibly , this is one mechanism by which tumor immune surveillance is restrained ( chalmin et al .
the possible further complexity of hsp - associated cellular export vesicles and cellular communications under stress conditions and its potential implications have already been discussed in an authoritative manner by de maio in an earlier perspective and reflection article ( de maio 2011 ) .
if we refute the possibility that hsp are damps , and we recognize the prominent role of hsp in cognate interactions with the immune system , we are confronted with the question of what the actual immunological significance of hsp may be .
the elevated levels of hsp in inflamed , traumatized , or reperfused tissues in combination with the extensive immune repertoire of cells with the capacity to recognize hsp indicate that these proteins may be biomarkers of damage , providing targets for immune mechanisms involved in restoration of tissue and immune homeostasis . with the recent rediscovery of regulatory t cells ( treg ) , the role of the immune system in homeostasis has received renewed interest . also the reinterpretation of self / nonself discrimination , as was revamped by the danger
concept , seems to have boosted our appreciation of mechanisms of immune homeostasis . currently , there is a flurry of interest in the host
the immune system can not tolerate becoming rampantly stimulated by foreign molecules , but has to figure out whether a certain stimulus is just microbial nonself or a signal of imminent danger . in the case of benign microbial nonself as present in our enteric microbiota , a carefully regulated response suffices or is even imperative .
it is in this relationship that a major role for treg cells is proposed . despite many technical obstacles ,
it is now widely accepted that treg cells do exist and can suppress immune responses in an antigen - specific manner , also in areas other than the gut .
natural treg cells are represented by a specialized subset of cd4dc25foxp3 t cells that are selected in the thymus on the basis of relatively high affinity self - recognition .
these cd4 t cells , which are also mostly cd25foxp3 , are programmed in the peripheral lymphoid organs or in the tissues to adopt a regulatory status .
notably , hsps are abundantly expressed in the thymus in the areas where positive selection of t cells takes place ( anderson et al .
therefore , hsp - specific natural treg cells may be selected in the thymus , whereas hsp - specific induced treg cells may originate from elevated hsp expression in stressed peripheral tissues . besides their prominent role in the maintenance of immune homeostasis in relation to symbiotic interactions with the gut microbiota ,
treg cells are implicated in the anti - inflammatory responses that are seen in autoimmunity , cancer , and infection ( vignali et al .
, treg cells help to resolve the pro - inflammatory response , thereby reducing bystander damage .
in addition , treg cells may be even more fundamental in the organization of the immune response .
for example , it has been shown that treg cells may function to aid in efficient cell entry into sites of infection ( lund et al .
, new evidence seems to have surfaced that hsp can be antigens that stimulate the activity of treg cells ( see also previous section ) . for several reasons , this latter possibility may be plausible and attractive .
every cell in the body harbors the full spectrum of hsp molecules . under stress , many of them are upregulated , and their fragments are processed and presented by mhc molecules on the cell surface .
some hsp70 family members ( hsc70 or hspa8 and in addition dnajb1 and hspc ) are involved in chaperone - mediated autophagy , a process whereby during stress or nutrient deprivation cytosolic proteins are reused by cells and are routed through a subcellular compartment that intersects with the mhc class ii route ( majeski and fred dice 2004 ) .
this means that , especially under stress , fragments of hsp70 may be loaded into mhc class ii products .
herewith hsp70 epitopes are being presented in a preferential manner to cd4 t cells , which includes tregs . based on other arguments , such as the autophagy - mediated disposition of proteins with a long half - life and mhc binding predictions ,
hsp70 has already been proposed as an important source of peptides to be loaded onto mhc class ii molecules , also in the absence of stress ( paludan et al .
a mass spectroscopy analysis of peptides eluted from mhc class ii obtained from stressed human b cells , revealed that hsp70 ( hspa1a , hspa6 , and hspa8 ) fragments composed a major portion of the bound collection of peptides ( dengjel et al .
thus , the immune system , including treg cells , has ample opportunity to encounter mhc - presented hsp epitopes , and this will be especially prevalent during inflammation or other stress conditions .
when trying to imagine how antigen - specific treg cells could work , one has to realize that it is unlikely that effective regulation is secondary to the presence of a very small number of autoantigen - specific treg cells present in a polyclonal population .
as already pointed out by shevach , a more likely scenario is that polyclonal treg cells are able to exert control because they are being regularly activated through their tcr by complexes of mhc class ii and ubiquitous self - peptides ( shevach 2009 ) .
if so , hsps would provide an excellent collection of prominently expressed certainly under stress
figure 1 represents three typical scenarios : sterile tissue damage ( autoimmune inflammation , reperfusion injury , heat stress ) , true danger imposed by pathogen invasion ( infection ) , and commensalism / symbiosis ( e.g. , exposure to gut microbiota ) .
maintenance of tissue homeostasis is required in all these instances , and one may assume that the immune system is having a major role here .
given the postulated capacity of hsps to trigger treg cells , it seems attractive to attribute , at least in part , the restoration of tissue and immune homeostasis to the activity of hsp - specific treg cells.fig .
1the immune system will restore homeostasis when the latter is challenged by sterile damage , pathogens , or commensals . in all cases ,
hsps are present and even upregulated host responses are terminated by regulation . in the host response , the hsp can be the targets for the regulation , such as for the regulation exerted by treg cells the immune system will restore homeostasis when the latter is challenged by sterile damage , pathogens , or commensals . in all cases ,
hsps are present and even upregulated host responses are terminated by regulation . in the host response , the hsp can be the targets for the regulation , such as for the regulation exerted by treg cells
there exist two ways by which heat shock proteins can interact with the immune system ( fig .
first of all , their intracellular upregulation as a consequence of cell stress will lead to upregulated mhc presentation of hsp fragments ( peptides ) at the cell surface making them visible to t cells .
secondly , they may be translocated by yet undefined mechanisms , as complete molecules to the cell surface or to the extracellular environment .
this would allow them to be encountered by nk cells , antibodies , and antigen - presenting cells .
besides active translocation , cell necrosis is probably a mechanism through which hsps are released into the extracellular environment .
it is safe to conclude that these two distinct contexts for hsp interactions with the immune system will lead to distinct immunological outcomes.fig .
the released hsp will be seen by receptors on antigen - presenting cells such as dc in combination with pamps .
it is possible that hsps do contribute to the pamp - elicited inflammatory response , thereby enhancing collateral tissue damage .
sterile inflammation will upregulate intracellular hsp in antigen - presenting cells such as dc which leads to the triggering of regulatory t cells that dampen inflammation extracellular hsps are released from necrotic cells when cells die from infection .
the released hsp will be seen by receptors on antigen - presenting cells such as dc in combination with pamps .
it is possible that hsps do contribute to the pamp - elicited inflammatory response , thereby enhancing collateral tissue damage .
sterile inflammation will upregulate intracellular hsp in antigen - presenting cells such as dc which leads to the triggering of regulatory t cells that dampen inflammation in principle , damp producing cell death is proposed to result mainly from necrosis . whether cell death is immunogenic , tolerogenic , or
2009 ) . activated apoptotic cells have adjuvant properties and induce expression of maturation markers ( cd80 , cd83 , and cd86 ) and secretion of pro - inflammatory cytokines in dcs ( johansson et al .
in contrast to this , t cells that succumb to activation - induced cell death after clonal expansion promote tolerance by stimulating regulatory cd8 t cells ( herndon et al .
thus , timing of cell death seems important : cell death at the peak of the immune response produces immune activation , whereas cell death during a waning immune response supports regulation .
most necrotic cells are considered to produce an immune response , but also here the cell type , the history of the cell , its mode of activation , and the manner of stress imposed on the cell may determine whether or not this form of cell death is immunogenic ( green et al . 2009 ) .
in other words , as long as we do not know exactly how to correlate the position of hsps with the type and circumstances of cell death , it will be hard to fully grasp the immunological role of hsp in cell death .
one of the problems that is associated with the immunogenicity of cell death is that cell death due to infection needs to be immunogenic , at least to some extent .
when dying cells would provide antigens , let us say hsp , that would lead to a firm tolerance or suppressive regulation , such tolerance or suppressive regulation would possibly include the microbial invader that led to cell death .
again , given the complexity of cell death immunogenicity , there may not be a simple one - dimensional role in cell death for hsp .
in the case of cell death due to infection , pamps may have an overriding effect driving a pro - inflammatory response , at least at the start of infection .
one can not exclude that extracellular hsps contribute a positive pro - inflammatory effect of pamp - activated cells , such as activated dcs by possibly amplifying their tlr signaling .
it is also possible that hsps form complexes with pamps to support pro - inflammatory activity by chaperoning the pamps involved or by synergistic effects . a similar discussion has been active with respect to hmgb-1 .
it was proposed that hmgb-1 released in the presence of tlr - binding pamps acted to promote inflammation , whereas hmgb-1 released in an environment devoid of pamps promoted tissue repair ( harris and raucci 2006 ) .
if this were the case , then it seems reasonable to assume a similar situation for hsp .
necrosis resulting from infection will lead to a pro - inflammatory response based on recognition of both pamps / damps and possibly hsps .
the ensuing elimination of the invaders would coincide with collateral damage . at this point ,
regulation in the form of active resolution , in part based on hsp recognizing treg cell , would kick - in and contribute to restoration of tissue homeostasis . from another point ,
intracellular hsp would , besides their main task in safeguarding against intracellular protein misfolding under stress , find its way to the cell surface in the context of mhc molecules and trigger a presumably regulatory response at the level of t cells .
in addition , there may be still be the somewhat theoretical issue of active concentrations of hsp . at low , more or less constitutive concentrations , hsp may help to maintain immune homeostasis by promoting treg cell activities .
however , it is theoretically possible that relatively high concentrations of hsp that are liberated at sites of tissue damage or infection cause a loss of regulatory capacity and contribute to pro - inflammatory responses .
this would imply that when cellular stress decreases , resolution would set in and treg cells would become prominent responders when local hsp concentrations fall ( quintana and cohen 2011 ) .
irrespective of possible pro - inflammatory effects of supra - constitutive concentrations of hsp , under physiological conditions , a dampening effect on the immune system would prevail .
this may be very much in line with the recent successful clinical interventions in autoimmune inflammatory diseases based on the administration of hsp peptides ( albani et al . 2011 ; fischer et al . | until recently , the immune system was seen solely as a defense system with its primary task being the elimination of unwanted microbial invaders .
currently , however , the functional significance of the immune system has obtained a much wider perspective , to include among others the maintenance and restoration of homeostasis following tissue damage . in this latter aspect , there is a growing interest in the identification of molecules involved , such as the so - called danger or damage - associated molecular patterns ( damps ) , also called alarmins .
since heat shock proteins are archetypical molecules produced under stressful conditions , such as tissue damage or inflammation , they are frequently mentioned as prime examples of damps ( bianchi , j leukoc biol 81:15 , 2007 ; kono and rock , nat rev immunol 8:279289 , 2008 ; martin - murphy et al . , toxicol lett 192:387394 , 2010 ) .
see for instance also a recent review ( chen and nunez , science 298:13951401 , 2010 ) .
contrary to this description , we recently presented some of the arguments against a role of heat shock protein as damps ( broere et al . , nat rev immunol 11:565-c1 , 2011 )
.
with this perspective and reflection article , we hope to elaborate on this debate and provide additional thoughts to further ignite this discussion on this critical and evolving issue . |
psoriasis is a chronic inflammatory skin disease that affects 3% of the united states population .
it manifests as well - demarcated , scaly patches on the skin , and it is associated with psoriatic arthritis and other comorbidities [ 24 ] .
the choice of psoriasis treatment varies depending on the severity and extent of skin involvement .
topical therapies are reserved for mild or localized disease , whereas phototherapy and systemic therapies are used for those with moderate - to - severe disease .
limitations with extended use of traditional oral systemic therapies include suboptimal efficacy , slow onset of therapeutic effect , toxicities , and teratogenicity ; these limitations have propelled the use of targeted therapies into the forefront of treatment for chronic inflammatory diseases such as psoriasis , psoriatic arthritis ( psa ) , and rheumatoid arthritis ( ra ) . over the last decade ,
biologic agents targeting specific components of the tumor necrosis factor ( tnf-) pathway have gained wide adoption for treatment of psoriasis as they achieved rapid clinical improvement with minimal side effects in multiple clinical trials and ongoing studies [ 69 ] .
however , high costs , potential risk for adverse events , and lack of persistent effects in some patients have fueled continued search for alternative therapies that target various components of the psoriasis inflammatory cascade .
cytokines and growth factors such as interleukin ( il)-1 , il-6 , il-12 , il-17 , il-20 , il-23 , interferon ( ifn)- , and tnf- within the abnormally upregulated th1 and th17 pathways have been implicated as key mediators in the immunopathogenesis of psoriasis by driving the activation and proliferation of epidermal keratinocytes [ 1014 ] . after the identification of increased protein tyrosine kinase activity in immunologic diseases ,
therapeutic agents targeting the protein tyrosine kinases have been developed , and they are effective and well - tolerated medications . the janus family of kinases is a subset of the protein tyrosine kinases .
preclinical studies have identified a number of cytokines involved in the psoriasis inflammatory cascade that utilize the janus family kinase ( jak ) signaling pathway . in this paper
, we discuss the molecular pathway of the jak - stat signaling cascade and the mechanism of action of the jak inhibitors .
we also examine in detail the treatment efficacy and safety of the currently available jak inhibitors for psoriasis treatment .
we also briefly discuss currently available data on treatment efficacy and safety in other chronic immune - mediated diseases such as ra and ulcerative colitis ( uc ) .
cytokine receptor signaling involves pathways such as the jak - stat pathway and the map kinase cascade .
the jak family consists of four members : jak1 , jak2 , jak3 , and tyk2 .
the activated stats dimerize and translocate into the cell nucleus to influence dna transcription , thus regulating gene expression .
the various combinations of jak pairs recruit different stat proteins , of which there are up to six types , and this allows for the wide range of downstream activities seen in the jak - stat pathways .
the jak - stat pathways activate or suppress the transcription of a wide array of genes that affect cell growth and apoptosis such as socs , nmi , bcl - xl , p21 , myc , and nos2
. however , jaks associate with specific cytokine receptors and therefore influence different aspects of immune cell development and function .
jak1 is associated with ifn , il-6 , il-10 receptors , and receptors containing common chains [ 21 , 22 ] .
jak2 is primarily involved in hematopoietic receptors as well as il-12 and il-23 . when dimerized with jak1 , jak3 acts selectively on receptors containing the common chain , which include il-2 , il-4 , il-7 , il-9 , il-15 , and il-21 , which are crucial to lymphocyte function .
tyk2 is associated with ifn , il-12 , and il-23 receptors in conjunction with jak2 [ 19 , 23 , 24 ] .
jak dysfunction has been associated with myeloproliferative diseases such as polycythemia vera , essential thrombocytopenia , and myelofibrosis as well as inherited immunodeficiencies including severe combined immunodeficiency and hyperimmunoglobulin e syndrome .
dysregulation of jak signaling has also been identified in multiple autoimmune disorders . due to their ability to selectively modulate immune function , targeted jak inhibitors are attractive candidates for immune - mediated diseases .
tofacitinib , a jak1 and jak3 inhibitor , and ruxolitinib , a jak1 and jak2 inhibitor , are the most extensively studied jak inhibitors in psoriasis . blocking these upstream components of the proinflammatory signaling pathways results in alterations in the immune response and suppresses the abnormal activation of the inflammatory cascade in diseases such as psoriasis ( figure 1 ) . in murine models
, tofacitinib suppressed the expression of il-23 receptors , il-17a , il-17f , and il-22 when t cells were stimulated with proinflammatory cytokines such as il-6 and il-23 .
inhibition of il-23 receptor expression results in suppression of th17 cell differentiation , which is a key driving factor in the pathogenesis of psoriasis .
additionally , tofacitinib 's inhibition of il-15 may play an important role in treating psoriasis as il-15 is highly expressed with enhanced binding activity in psoriatic lesions and associated with increased resistance to keratinocyte apoptosis .
ruxolitinib acts by inhibiting jak1 and jak2 pathways through blocking stat3 phosphorylation due to il-6 , il-12 , or il-23 , resulting in the suppression of pathogenic th17 cells differentiation [ 2931 ] .
this leads to a dose - dependent decrease in production of il-17 , il-20 , and il-22 .
additionally , the suppression of stat3 phosphorylation reduces ifn- expression , which is one of the most potent activators of keratinocyte proinflammatory function . in a study by fridman et al . , topical application of ruxolitinib in murine models reduced lymphocytic infiltration , inhibited acanthosis , and suppressed production of il-22 induced by intradermal il-23 .
jak inhibitors act on multiple cell lines that contribute to the clinical manifestations of psoriasis [ 14 , 32 ] .
tofacitinib , a jak1 and jak3 inhibitor , has undergone the most extensive clinical studies of jak inhibitors in psoriasis treatment [ 3337 ] . in a phase
30 mg b.i.d . , 50 mg b.i.d . , and 60 mg once daily ( q.d . ) was administered to 59 patients with mild - to - moderate psoriasis . on day 14
had dose - dependent improvement in the least squares mean ( lsm ) of percentage change in the psoriatic lesion severity sum ( plss ) score compared to the placebo group ( p < 0.01 ) .
three of the eight patients receiving tofacitinib 50 mg had plss scores of 0 by day 14 from baseline scores of 46 . on day 14 , the physician 's global assessment ( pga ) score improvement , defined as almost clear or
clear and a 2-point pga score improvement , in patients receiving 50 mg b.i.d .
of the skin biopsy samples obtained , marked histological improvements were noted in patients receiving a dosage of 30 mg b.i.d . when compared to their baseline , while lesional biopsies from the placebo group showed minimal or no change compared to baseline .
of the 16 adverse events in 10 patients within this study , headaches ( n = 5 ) and nausea ( n = 3 ) were most common , and all suspected treatment - related adverse effects were considered mild .
of the laboratory studies conducted , boy et al . reported elevated total cholesterol , low - density lipoprotein cholesterol , and triglyceride in the treatment groups when compared to the placebo group . in a 12-week phase iib study ,
papp et al . described the efficacy and safety of oral tofacitinib 2 mg b.i.d .
, 5 mg b.i.d . , or 15 mg b.i.d . in 197 moderate - to - severe psoriasis patients .
papp et al . reported psoriasis area and severity index ( pasi ) 75 response rates of 25.0% ( 2 mg ; p < 0.001 ) , 40.8% ( 5 mg ; p < 0.0001 ) , and 66.7% ( 15 mg ; p < 0.0001 ) versus 2.0% in the placebo group at week 12 .
more pasi 75 responders were observed in all treatment groups as early as week 4 and maintained through week 12 compared to placebo patients ( p < 0.05 to p < 0.001 ) . upper respiratory tract infections , nasopharyngitis , and headache were the most common adverse effects reported by the patient cohort .
three patients experienced five serious adverse events including angina pectoris , pyelonephritis , urosepsis , and atrial fibrillation .
discontinuation from the study was reported in 2.0% , 4.1% , and 6.1% of patients in the 2 , 5 , and 15 mg b.i.d .
serum creatinine increased ( mean 0.04 mg dl ) in the 15 mg b.i.d .
one case of alanine aminotransferase elevated greater than 2.5 times the upper limit of normal was documented in the 15 mg b.i.d .
tofacitinib treatment was associated with mild , dose - dependent decreases in hemoglobin of 0.15 , 0.20 , 0.14 , and 0.71 g dl for placebo and tofacitinib 2 , 5 , and 15 mg b.i.d .
groups , respectively , at week 12 [ 34 , 38 ] . additionally , mean absolute neutrophil counts decreased at higher doses of tofacitinib with a maximum mean decrease of 0.9 10 mm in patients receiving 15 mg b.i.d . at week 4 .
however , these values began to return to baseline values from weeks 4 to 8 [ 34 , 38 ] .
in this same study cohort , mamolo et al . described the patient - reported outcomes of these 197 patients with moderate - to - severe psoriasis through six patient questionnaires . at week 12 , the authors reported greater lsm changes from baseline for the dermatology life quality index , itch severity score , and short form-36 questionnaire mental component for all active drug arms versus placebo ( p < 0.05 ) .
a total of 35.1% , 38.5% , and 74.4% of patients in the 2 , 5 , and 15 mg groups , respectively , reported clear or almost clear on the patient global assessment of psoriasis versus 2.9% for the placebo group ( p < 0.0001 for all doses ) .
tofacitinib has also been utilized as a topical formulation . in a vehicle - controlled phase iia trial studying a topical tofacitinib ointment formulation , ports et al .
reported the data on 71 mild - to - moderate psoriasis patients treated with tofacitinib 2% ointment 1 b.i.d . versus tofacitinib 2% ointment 2 b.i.d . for 2 weeks to a single , fixed 300 cm treatment area containing a target plaque .
this study noted improvement in the target plaque severity score ( tpss ) at week 4 for ointment 1 ( lsm-54.4% ) versus vehicle 1 ( lsm-41.5% ; one sided 90% upper confidence limit < 0 ) but not for ointment 2 ( lsm-24.2% ) versus vehicle 2 ( lsm-17.2% ; one sided 90% upper confidence limit > 0 ) .
systemic concentrations ( > 0.100 ng ml ) were detected in 12 ( 60% ) of 20 patients receiving ointment 1 for at least one time point compared to 6 ( 26% ) of 23 patients receiving ointment 2 .
however , these serologic levels were 40-fold lower than the systemic concentration achieved at the lowest oral dose tested ( 2 mg b.i.d . ) .
a total of 25 out of 71 patients reported adverse effects ; all of them were categorized as mild or moderate .
nasopharyngitis ( n = 4 ) and urinary tract infections ( n = 3 ) were the most common .
clinical trials testing tofacitinib administered either orally or topically for psoriasis have shown statistically significant symptom improvement in patients with psoriasis when compared to their placebo counterparts .
there are multiple phase iii trials ( nct01186744 , nct01276639 , nct01309737 , nct01163253 , and nct01815424 ) studying the efficacy and safety of tofacitinib in psoriasis patients . one phase iii trial ( nct01241591 ) has compared oral tofacitinib 5 mg or 10 mg b.i.d . versus etanercept 50 mg twice weekly for 12 weeks for patients with moderate - to - severe psoriasis , and the results are pending at the time of writing of this paper .
two phase iia trials ( nct01246583 and nct00678561 ) and one phase iib trial ( nct01831466 ) of tofacitinib ointments are under way as well . additional phase iii studies ( nct01519089 , nct01976364 , and nct01877668 ) are examining the efficacy and safety of tofacitinib in patients with psa .
one phase iii study ( nct01882439 ) has begun recruiting participants for tofacitinib in psa patients with inadequate response to at least one tnf inhibitor .
ruxolitinib , a jak1 and jak2 inhibitor , has primarily been studied as a topical ointment for mild - to - moderate psoriasis , and it has been compared to other topical therapies , which include topical steroids and topical calcipotriene [ 19 , 40 ] . in a phase ii study ,
punwani et al . described the treatment of 28 patients with limited psoriasis ( < 20% body surface area ) who were divided into 5 treatment groups : ruxolitinib 0.5% cream q.d . versus vehicle ( group 1 ) , ruxolitinib 1.0% cream q.d . versus vehicle ( group 2 ) , ruxolitinib 1.5% cream b.i.d .
versus vehicle ( group 3 ) , ruxolitinib 1.5% cream versus calcipotriene 0.005% cream b.i.d .
( group 4 ) , or ruxolitinib 1.5% cream versus betamethasone dipropionate 0.05% cream b.i.d . for 28 days ( group 5 ) .
the lesions were evaluated by the total lesion score ( 012 ) , which was a composite of the target lesion scores for erythema , scaling , and thickness , each rated on a scale of 0 to 4 . on day 28 , the total lesion scores were relatively similar to the vehicles in patients receiving ruxolitinib 0.5% cream , whereas the total lesion scores decreased by 53% and 54% in patients receiving ruxolitinib 1.0% cream q.d . and ruxolitinib 1.5% cream b.i.d .
, respectively , versus 32% and 32% in patients in their respective vehicle cohorts ( p = 0.033 and 0.056 , resp . ) .
the authors also noted that the onset of effect and efficacy of ruxolitinib 1.5% cream b.i.d .
mean plasma concentrations of ruxolitinib for the 0.5% , 1.0% , and 1.5% cream were 0.32 0.40 , 0.96 0.82 , and 2.10 1.78 nmol l , all of which were well below the plasma concentration determined to be pharmacologically active , which suggests that the topical ruxolitinib preparations are unlikely to cause systemic adverse effects .
adverse effects including stinging , itching , irritation , pain , dryness , exfoliation , and/or redness at the application site were all mild and reported in 6 ( 20% ) of ruxolitinib - treated lesions , 5 ( 28% ) of the vehicle - treated lesions , 2 ( 33% ) of the calcipotriene - treated lesions , and 2 ( 40% ) of the betamethasone - treated lesions . in a study referenced by ortiz - ibanez et al .
, 200 mild - to - moderate psoriasis patients were divided into 3 treatment groups receiving topical ruxolitinib at doses of 0.5% , 1% , and 1.5% cream for 3 months in a phase iib vehicle - controlled trial ( primary publication of the study results are not yet in the literature ) . in the 1% cream cohort ,
local irritation was cited as the most frequent adverse effect , and respiratory infections were reported in 6.7% of the patients receiving ruxolitinib
1.0% cream versus 2% of patients in the placebo group . of the early clinical studies available , ruxolitinib may be a promising agent for topical treatment of psoriasis .
there are two additional jak inhibitors undergoing investigation for the treatment of moderate - to - severe psoriasis .
k , a selective jak3 inhibitor , has undergone a phase iia dose escalation study ( nct01096862 ) in a cohort of 124 patients with moderate - to - severe psoriasis ( see http://www.clinicaltrials.gov ) .
incb-28050/ly3009104 , a jak1 and jak3 inhibitor , is being examined in a phase iib dose ranging study ( nct01490632 ) in 240 moderate - to - severe psoriasis patients ( see http://www.clinicaltrials.gov ) .
additional jak inhibitors have been developed as potential therapies for psoriasis such as vx-509 and r-348 , but there are no documented clinical trials examining these agents in psoriasis patients .
jak inhibitors in early phase trials produced significant clinical improvement in psoriasis when compared to placebo groups .
these findings show that cytokine signaling through the jak pathway is an important driver in the pathogenesis of psoriasis .
the jak pathway is involved in the intracellular signaling that affects various cytokines , which propagate a wide range of downstream effects .
the jak inhibitors currently under investigation target one or more members of the jak family .
their mechanism of action involves targeted inhibition of both upstream and downstream components of proinflammatory pathways in psoriasis , and these medications represent a promising class of agents for the treatment of psoriasis .
tofacitinib and ruxolitinib are the two jak inhibitors that have been most studied in psoriasis .
tofacitinib , studied as both an oral and topical administration , has undergone the most extensive clinical testing thus far with ongoing phase iii clinical trials likely completed at the time of publication of this manuscript .
phase i and ii clinical trials on tofacitinib , a jak1 and jak3 inhibitor , reported dose - dependent improvement in patients with psoriasis when compared to the placebo groups [ 3336 ] .
ruxolitinib , a jak1 and jak2 inhibitor , has exclusively been studied as a topical formulation for the treatment of mild - to - moderate psoriasis .
the plasma concentrations of ruxolitinib in patients receiving topical medication were less than 1% of the concentrations required for systemic activity in healthy volunteers , suggesting that ruxolitinib locally inhibits the propagating factors of psoriasis rather than through systemic effects .
considering the issues associated with targeted agents requiring invasive administration in psoriasis , the noninvasive administration route of jak inhibitors is a favorable attribute of these drugs .
the data discussed herein suggest that jak inhibitors represent an important choice in the current armamentarium of psoriasis therapies . due to the wide array of downstream targets that jak
inhibition affects , concerns have been raised that jak inhibitors may impair the body 's ability to fight infections as well as modify hematopoietic development and function .
although the safety profiles of tofacitinib and ruxolitinib were acceptable in the early phase trials , there is still concern for unknown long - term side effects with these medications [ 3335 , 38 , 40 ] . of the studies investigating tofacitinib , upper respiratory tract infections , headaches , and mild nausea
were cited as the most common adverse effects experienced by patients [ 33 , 34 ] .
papp et al . noted that the rate and type of adverse effects between the treatment and placebo groups were relatively similar .
the safety of tofacitinib has been more extensively studied in phase trials for ra patients , and the side effect profiles were similar to those reported in psoriasis patients .
based on murine models , there has also been concern for possible reactivation of tuberculosis and other latent infections with the use of tofacitinib [ 39 , 41 ] . although no cases of tuberculosis were reported in psoriasis patients treated with tofacitinib , cases of tuberculosis have been reported in phase trials for ra patients .
tofacitinib treatment was associated with dose - dependent decreases in mean neutrophil counts and hemoglobin . however
, these changes did not require intervention and the blood counts normalized during the treatment period .
increases in mean low - density lipoprotein cholesterol , high - density lipoprotein cholesterol , total cholesterol , triglycerides , and transaminase levels were also observed in selected patients treated with tofacitinib [ 33 , 34 ] .
the manifestation of these serum changes is unclear , and further investigation is needed to determine whether any intervention is required .
this was likely due to the minimal systemic absorption based on the mean serum drug levels .
punwani et al . also noted that patients treated with ruxolitinib ointment had fewer adverse effects than patients treated with the vehicle , calcipotriene , or betamethasone applications , supporting the safety profile of ruxolitinib .
although the safety profiles of both tofacitinib and ruxolitinib appear promising with short - term use , the results must be interpreted with caution as these findings can not confirm their safety with long - term use .
findings from trials examining jak inhibitors in other immune - mediated diseases may guide our understanding of these agents in psoriasis patients .
jak inhibitors have been studied extensively in other chronic inflammatory conditions such as ra and uc [ 4250 ] .
tofacitinib has been the most extensively studied jak inhibitor in the realm of inflammatory diseases , specifically in ra .
it is an efficacious treatment option either as monotherapy or in combination with methotrexate in patients with moderate - to - severe ra [ 4244 , 46 , 47 , 49 , 50 ] .
of particular interest , tofacitinib achieved significant clinical response in patients who were refractory to treatments such as methotrexate monotherapy , disease - modifying antirheumatic drugs ( dmards ) , or tnf inhibitors in phase ii and phase iii clinical studies [ 42 , 43 , 46 , 47 , 50 ] . in a 12-month phase iii trial , van vollenhoven et al . reported the treatment of 717 ra patients on stable doses of methotrexate and receiving tofacitinib 5 mg b.i.d .
the authors found that the clinical response rates were better than placebo ( 28.3% ) in patients receiving tofacitinib 5 mg ( 51.5% ) , 10 mg ( 52.6% ) , and adalimumab ( 47.2% ; p < 0.001 for all comparisons ) , indicating not only does tofacitinib produce clinically significant improvement in ra symptoms but also it achieves a numerically similar response rate as adalimumab [ 41 , 50 ] .
tofacitinib is being studied in clinical trials for the treatment of psoriatic arthritis , ankylosing spondylitis , atopic dermatitis , and keratoconjunctivitis sicca .
clinical experience with these therapeutic options in inflammatory diseases such as ra and uc has guided the way for their potential use as agents for psoriasis .
jak inhibitors are new , promising therapies in psoriasis , and they have different safety profiles from the existing traditional oral systemic medications or biologic medications . of the jak inhibitors studied for psoriasis , tofacitinib has been most extensively studied , and phase iii study results ( nct01241591 ) comparing tofacitinib to etanercept are pending .
ruxolitinib , asp015 k , and ly3009104 are among the other jak inhibitors being studied for clinical use .
overall , jak inhibitors represent a new class of efficacious treatments to reduce disease severity and improve quality of life among psoriasis patients . | janus kinase ( jak ) pathways are key mediators in the immunopathogenesis of psoriasis . psoriasis treatment has evolved with the advent of targeted therapies , which inhibit specific components of the psoriasis proinflammatory cascade .
jak inhibitors have been studied in early phase trials for psoriasis patients , and the data are promising for these agents as potential treatment options .
tofacitinib , an oral or topically administered jak1 and jak3 inhibitor , and ruxolitinib , a topical jak1 and jak2 inhibitor , have been most extensively studied in psoriasis , and both improved clinical symptoms of psoriasis .
additional jak1 or jak3 inhibitors are being studied in clinical trials . in phase iii trials for rheumatoid arthritis ,
tofacitinib was efficacious in patients with inadequate responses to tumor necrosis factor inhibitors , methotrexate monotherapy , or disease - modifying antirheumatic drugs .
the results of phase iii trials are pending for these therapies in psoriasis , and these agents may represent important alternatives for patients with inadequate responses to currently available agents .
further investigations with long - term clinical trials are necessary to verify their utility in psoriasis treatment and assess their safety in this patient population . |
in an attempt to overcome the gap between recommended levels of fiber consumption versus what is actually consumed in a typical american diet , fiber supplements have become a popular option as a convenient , concentrated source of fiber . given that a fiber supplement is an isolated fiber source consumed in addition to an existing diet , and many of the additional benefits described above for meal replacement are not provided by adding an isolated fiber source , it becomes essential to have a more in - depth understanding of the unique physiochemical characteristics of each fiber supplement and how these characteristics are , or are not , associated with 1 or more clinically meaningful health benefits .
the term fiber supplement implies that regular ( daily ) consumption will provide health benefits that may be missing from a low - fiber diet , but for most fiber supplements , this implication is not supported by clinical data .
health benefits derived from fiber supplements are primarily a function of the fiber s physical effects in the small bowel ( eg , cholesterol lowering , improved glycemic control , satiety / weight loss ) and large bowel ( improved stool form and reduced symptoms in constipation , diarrhea , and irritable bowel syndrome [ ibs ] ) .
there are 4 main characteristics of fiber supplements that drive clinical efficacy : solubility , degree / rate of fermentation , viscosity , and gel formation .
solubility defines whether a fiber supplement will dissolve in water ( soluble ) or remain as discreet insoluble particles.3,11 for soluble fibers , viscosity refers to the ability of some fibers to thicken when hydrated , in a concentration - dependent manner ( figure 1).3,1115 gel formation refers to the ability of a subset of soluble viscous fibers to form cross - links , resulting in a viscoelastic gel when hydrated ( figure 2).3,1113 linear versus branched polymers .
swept out by a fully extended linear fiber is much greater than a fiber with an equal number of sugar units ( same molecular weight ) but with a bush - like , highly branched configuration . because the volume occupied by a polymer molecule is a function of the radius cubed , even small increases in effective hydrodynamic size can translate into a large increase in viscosity for linear fibers .
drawings representing viscous linear polymers ( top ) and gel - forming linear polymers ( bottom ) .
long - chain linear polymers orient parallel to adjacent fibers and increase viscosity in a concentration - dependent manner .
some long - chain linear polymers also can form cross - links that create a gel in a concentration - dependent manner ( behave as a viscoelastic solid ) .
gel formation is an important driver of several metabolic health benefits for dietary fiber supplements , including cholesterol lowering , improved glycemic control , satiety , weight control , and stool normalization ( soften hard stool in constipation and firm loose / liquid stool in diarrhea ) .
( drawings recreated with permission from john d. keller , jr , keller konsulting llc , freehold , nj . ) fermentation refers to the rate and degree to which a dietary fiber , after resisting enzymatic digestion in the small bowel , can be degraded by gut bacteria , producing fermentation byproducts such as short chain fatty acids and gas.3 most fibers are not exclusively soluble or insoluble , so for the purposes of this review , the predominant characteristic will be discussed ( eg , a fiber that is 70% soluble will be considered a soluble fiber ) . using the 4 fiber characteristics described above
, fiber supplements can be divided into 4 clinically meaningful categories : insoluble , poorly fermented ( eg , wheat bran ) : when you think of insoluble fiber , think of plastic ( clinical studies described later actually used plastic particles to mimic effects of wheat bran ) : does not dissolve in water ( no water - holding capacity ) ; poorly fermented ; can exert a laxative effect by mechanical irritation / stimulation of gut mucosa if particles are sufficiently large and coarse ( plastic effect ) ; small smooth particles ( eg , wheat bran flour / bread ) have no significant laxative effect ; insoluble fiber does not gel or alter viscosity and thus does not provide other ( gel - dependent ) fiber health benefits .
soluble , nonviscous , readily fermented ( eg , inulin , wheat dextrin , oligosaccharides , resistant starches ) : dissolves in water ; no increase in viscosity ; rapidly and completely fermented ( once fermented , the fiber is no longer present in stool , rapid gas formation , increased flatulence , energy harvest [ calorie uptake ] from fermentation by - products ) ; may alter the numbers of specific bacteria in the gut ( eg ,
effect ) ; no laxative effect at physiologic doses ; does not gel or alter viscosity and thus does not provide any of the gel - dependent fiber health benefits .
readily fermented fibers are part of an emerging area of science relating to their effects on the gut microbiome , but to date , the marketed fiber supplements have no established clinically meaningful health benefits . soluble viscous / gel forming , readily fermented ( eg , -glucan [ oats , barley ] , raw guar gum ) : dissolves in water , forms a viscous gel ( eg , oatmeal ) , increases chyme viscosity to slow nutrient absorption and improve glycemic control , lowers elevated serum cholesterol , readily fermented ( gas formation , energy harvest [ calorie uptake ] from fermentation by - products ) , fermentation results in loss of gel and water - holding capacity , and thus , no significant laxative effect and no retained gel to attenuate diarrhea .
soluble viscous / gel forming , nonfermented ( ie , psyllium ) : dissolves in water ; forms a viscous gel ; increases chyme viscosity to slow nutrient absorption and improve glycemic control , lowers elevated serum cholesterol ; not fermented ( no gas production , no calorie harvest from fermentation by - products ) ; because it is not fermented , it remains gelled throughout the large bowel , providing a dichotomous stool - normalizing effect : softens hard stool in constipation ( relieves / prevents constipation ) and firms / forms loose / liquid stool in diarrhea ( relieves / prevents diarrhea ) , and normalizes stool form in ibs .
the small intestine is 7 m long and divided anatomically into 3 regions : duodenum , jejunum , and ileum .
the mucosa of the small intestine is studded with millions of small villi , each covered with 1000 microvilli per 0.1 m , making the small intestine the largest body surface exposed to the outside world ( approximately 250 m , roughly the size of a tennis court).3,16 delivery of acidic nutrients into the duodenum ( proximal small bowel ) stimulates pancreatic secretions ( inorganic = water , bicarbonate , and electrolytes ; organic = digestive enzymes ) as well as the release of bile from the gall bladder .
the total quantity of fluid absorbed by the small bowel each day is a combination of fluids consumed ( 1.5 l / d ) and the digestive juices secreted ( 6 - 7 l / d ) . in the fed state ,
the motor activity of the small bowel predominantly consists of segmental ( mixing ) contractions.3,16 these segmental contractions mix chyme back and forth , exposing food particles to digestive enzymes and bile and facilitating exposure of digested nutrients to the absorptive brush border of the mucosa for absorption .
chyme , the liquid content of the small intestine , is normally very low in viscosity and is easily mixed with digestive enzymes for degradation and easily exposed to the villi for absorption of nutrients .
the very large surface area of the mucosa normally results in efficient absorption of nutrients , which occurs early in the proximal small bowel.3,16 introduction of insoluble fiber ( eg , wheat bran ) or soluble nonviscous fiber ( eg , inulin , wheat dextrin ) has no significant effect on the rate of nutrient absorption in the small bowel because neither type forms a gel to alter the viscosity of chyme .
in contrast , introduction of a soluble viscous , gel - forming fiber ( eg , guar gum , psyllium , high - molecular - weight -glucan ) will significantly increase the viscosity of chyme in a dose - dependent manner , which will slow the mixing of chyme with digestive enzymes .
this will lead to a slowing of the degradation of complex nutrients into simple , absorbable components and also slow turnover of chyme at the villi , all of which will slow the absorption of glucose and other nutrients.3 this slowing of nutrient degradation and absorption lowers peak serum glucose concentration after a meal and delivers nutrients further into the small bowel for absorption .
an effective gelling fiber can delay the absorption of nutrients long enough to deliver nutrients to the distal ileum , where they are not normally present .
nutrients delivered to the distal ileum stimulate mucosal receptors to initiate a cascade of metabolic responses , 1 of which is the release of glucagon - like peptide-1 into the blood stream .
glucagon - like peptide-1 is a short - lived ( 2-minute half - life ) peptide that significantly decreases appetite , increases insulin secretion , decreases glucagon secretion ( a peptide that stimulates glucose production in the liver ) , increases pancreatic -cell growth ( cells that produce insulin ) , improves insulin production and sensitivity , and slows gastric emptying and small bowel transit via a feedback loop called the
phenomenon.3 all of the above metabolic responses are therapeutic targets for treating type 2 diabetes mellitus .
taken together , the sum of these phenomenon leads to a gel - dependent improvement in glycemic control for patients with type 2 diabetes and those at risk for developing the disease ( eg , metabolic syndrome).3,14,1722
there are 2 primary methods for assessing the effects of fiber supplements on glycemic control : an acute postprandial study and a long - term assessment of glycemic control .
the acute postprandial test ( glucose tolerance test ) provides a glucose load ( eg , 50 g glucose solution ) with and without fiber supplementation .
blood glucose concentrations are drawn at frequent , predetermined intervals over a few hours to assess the rate of glucose absorption .
glucose is normally very rapidly absorbed in the most proximal region of the small intestine , resulting in a relatively fast rise in blood glucose and a high peak concentration . because of a short lag in insulin response
, this is typically followed by rapid decline in glucose with a transient excursion below the baseline level ( figure 3a , c ) .
this transient hypoglycemia is caused by the lag in insulin response , which tends to stay elevated past the point where the blood glucose concentration has returned to baseline .
introduction of a viscous , gel - forming fiber ( eg , guar gum , psyllium , high - molecular - weight -glucan ) can delay nutrient absorption to more distal regions of the small bowel ( b ) .
rapid nutrient absorption ( c : grey line , corresponds with a ) is reflected by the higher peak concentration of blood glucose followed by a transient hypoglycemic trough below baseline . with the introduction of a viscous , gel - forming soluble fiber , the delay in nutrient absorption ( c : black line , corresponds with b ) results in an attenuation of glucose excursions : lower peak concentration of blood glucose , and attenuated hypoglycemic trough .
( drawings recreated with permission from thomas wolever , phd , university of toronto . )
it has been established for more than 3 decades that the viscosity of a gel - forming fiber supplement is highly correlated with minimizing the high and low excursions of postprandial glucose . in a study published in 1978,23
volunteers underwent glucose ( 50 g ) tolerance tests with and without the addition of several fiber supplements , including guar gum .
native guar gum is a highly viscous , gel - forming fiber , and it exhibited a clinically meaningful decrease in both postprandial blood glucose and insulin concentrations .
this beneficial response , however , was abolished when the guar gum was hydrolyzed to a nonviscous form , as is typically marketed today partially hydrolyzed guar gum .
the study showed that a reduction in postprandial blood glucose was highly correlated with the viscosity of a gel - forming fiber ( r = 0.926 ; p < .01 ) , as was a slowing of small bowel transit ( r = 0.885 ; p < .02 ) . taken together , a high - viscosity , gel - forming fiber supplement ( eg , raw guar gum , high - molecular - weight -glucan , psyllium ) can provide a clinically meaningful effect on elevated blood glucose level in a viscosity / dose - dependent manner , but nonviscous soluble fiber supplements ( eg , wheat dextrin , inulin ) do not provide a gel - dependent , clinically meaningful glycemic benefit.1,3 the second method , long - term assessment of glycemic control , entails multimonth , well - controlled , randomized clinical studies that assess a fiber s effects on glycemic control in the target population .
these long - term studies provide evidence of a sustained effect and should be the standard for establishing a clinically meaningful therapeutic response for a given fiber supplement . numerous multimonth ( 26 months ) clinical studies have demonstrated that consumption of a soluble , gel - forming fiber supplement with meals can improve glycemic control ( lowers fasting blood glucose , insulin , and hemoglobin a1c concentrations ) in subjects at risk for type 2 diabetes ( eg , metabolic syndrome ) and in patients being treated for type 2 diabetes.1,3,2438 an example is an 8-week , placebo - controlled clinical study that evaluated psyllium ( 5.1 g bid ) for improved glycemic control in 49 patients being treated for type 2 diabetes ( fasting blood glucose and hemoglobin a1c at baseline : psyllium group , 208 mg / dl and 10.5 ; placebo group , 179 mg / dl and 9.1).38 after 8 weeks of treatment , fasting blood glucose for the psyllium group showed a significant decrease ( 89.7 mg / dl ; p < .05 ) versus placebo .
hemoglobin a1c also showed a significant decrease ( 3.0 ) versus placebo.38 note that the improvement in glycemic control observed with psyllium was above that already conferred by a restricted diet and stable doses of a sulfonylurea and/or metformin .
the long - term effects of an effective gel - forming fiber on fasting blood glucose concentrations are proportional to baseline glycemic control : there is no significant effect on normal blood glucose concentrations in healthy subjects.39 a moderate effect in patients with prediabetes and metabolic syndrome ( eg , 19.8 mg / dl for psyllium 3.5 g bid ; 9 mg / dl for guar gum 3.5 g bid),26 and a larger effect in patients with type 2 diabetes ( eg , psyllium , 35.0 to 89.7 mg / dl).34,38 note that gel - forming fiber supplements will not directly cause hypoglycemia ( suppression of glucagon by glucagon - like peptide-1 does not occur at hypoglycemic levels ) , but for patients being treated for type 2 diabetes , fasting blood glucose should be closely monitored with the initiation of an effective fiber therapy as the fiber supplement may reduce the required dose of hypoglycemic drugs .
it is well established that reducing elevated serum low - density lipoprotein ( ldl)-cholesterol concentration reduces the risk of coronary artery disease.40 it has been estimated that a 1% reduction in ldl - cholesterol concentration reduces the risk of coronary artery disease by 1.2% to 2.0%.41 similar to the gel - dependent nature of improved glycemic control with fiber supplements , lowering elevated serum cholesterol concentrations is also a gel - dependent phenomenon in the small bowel , and the effectiveness of cholesterol lowering is highly correlated with the viscosity of the gel - forming fiber : the higher the viscosity of a gel - forming fiber is , the greater the effect on lowering elevated cholesterol concentrations.37 clinical studies have shown that the viscosity of a gel - forming fiber is actually a better predictor of cholesterol - lowering efficacy than is the quantity of fiber consumed.42 the primary mechanism by which gel - forming fibers lower serum cholesterol is by trapping and eliminating bile .
bile is secreted by the liver ( normally 6001000 ml / d ) to emulsify large fat particles into many small particles for digestion by lipase enzymes and absorption across the mucosa.16 bile is normally highly conserved , recovered in the distal ileum , and recycled up to several times within a single meal . when bile is trapped in a gel - forming fiber and eliminated via stool
cholesterol is a component of bile , and the liver uses serum stores of cholesterol to generate more bile , effectively lowering serum ldl - cholesterol and total cholesterol concentration , without affecting high - density lipoprotein cholesterol.43 to assess the importance of viscosity for a gel - forming fiber in lowering elevated serum cholesterol concentration , a clinical study compared the cholesterol - lowering effects of a medium - viscosity blend of gel - forming fibers ( psyllium , pectin , guar gum , and locust bean gum ) with those of an equal amount ( three 5-g servings per day for 4 weeks ) of low - viscosity gum arabic ( acacia gum , highly branched ) in 26 patients with hypercholesterolemia.44 the medium - viscosity gel - forming blend exhibited a 10% reduction in total cholesterol concentration ( p < .01 ) and a 14% reduction in ldl - cholesterol concentration ( p < .001 ) , with no significant change in high - density lipoprotein or triglyceride levels . in contrast , the low - viscosity gum arabic - treated group showed no change in any plasma lipid characteristics.44 a second publication with 4 studies ( duration 412 weeks ) explored the plasma lipid - lowering effects of a variety of soluble dietary fibers.45 the studies were randomized , double - blind , placebo - controlled trials involving men and women with hyperlipidemia ( plasma cholesterol > 200 mg / dl ) . low - viscosity gum arabic ( acacia gum ) ( 15 g / d for 4 weeks ) did not produce a significant lipid - lowering effect versus placebo .
in contrast , 15 g / d of a medium - viscosity blend of soluble fibers ( psyllium , pectin , guar gum , and locust bean gum ) consumed for 4 weeks yielded significant reductions in total cholesterol ( 8.3% ) and ldl - cholesterol ( 12.4% ) concentrations ( p < .001 ) , similar to the 10 g / d high - viscosity raw guar gum .
the lipid - lowering benefit of the medium - viscosity blend of soluble fibers ( psyllium , pectin , guar gum , and locust bean gum ) also showed a dose - response effect for reducing ldl - cholesterol concentration : placebo , + 0.8% ; 5 g / d , 5.6% ; 10 g / d , 6.8% , and 15 g / d , 14.9% ( all doses p < .01 vs placebo ) .
the effects of the gel - forming fibers on plasma lipids were similar for both men and women .
the authors concluded that the findings support the usefulness of medium- and high - viscosity gel - forming fibers as a cholesterol - lowering therapy but cautioned against ascribing cholesterol lowering benefits solely on a classification of solubility.45 as with improved glycemic control , the viscosity of the gel - forming fiber is the key driver of efficacy for lowering cholesterol in patients with hyperlipidemia . also similar to the gel - dependent effect glycemic control , the potential for a cholesterol - lowering benefit
is highly influenced by the baseline cholesterol level : gel - forming fibers have no appreciable effect on cholesterol concentrations in healthy subjects with normal cholesterol concentrations but exhibit a progressively greater benefit as baseline cholesterol exceeds normal concentrations .
the cholesterol - lowering benefit of gel - forming fiber supplements is observed in addition to the benefits conveyed by the prescription drugs in patients already being treated for hyperlipidemia .
eight clinical studies have shown that a gel - forming fiber ( psyllium ) enhanced the cholesterol - lowering benefit of prescription drugs when dosed as a cotherapy to statin drugs and bile sequestrants.4653 there are only 2 fiber supplements approved by the food and drug administration to claim a reduced risk of cardiovascular disease by lowering serum cholesterol : -glucan ( oats and barley ) and psyllium , both gel - forming fibers.54 an effective gel - forming fiber supplement can actually lower the required dose of a prescription statin drug . for example , in a 12-week randomized , double - blind study including 68 patients with hyperlipidemia , a low dose of simvastatin ( 10 mg ) combined with psyllium ( 15 g / d , divided doses before meals ) was superior to the low dose of simvastatin alone ( 63 vs 55 mg / dl , respectively ; p = .03 ) and identical to a high dose of simvastatin alone ( 20 mg , 63 mg / dl ) for lowering elevated serum ldl - cholesterol concentration.55 gel - forming fibers can provide an effective cotherapy for hypoglycemic and cholesterol - lowering drugs to help reduce required doses and potentially reduce side effects . as described above , low - viscosity fibers ( gum arabic / acacia gum , methylcellulose ) and nonviscous supplements ( eg , inulin , wheat dextrin ) do not exhibit a cholesterol - lowering benefit.37,44,45,56,57
it is important to recognize the difference between replacement with dietary fiber that is intrinsic and intact in whole foods and supplement with an isolated fiber source .
fiber supplements can not be presumed to have the same health benefits that are associated with dietary fiber that is intact and intrinsic in whole foods .
the clinically proven health benefits for fiber supplements are associated with specific characteristics ( eg , viscous gel ) , and only a minority of marketed fiber products provide health benefits ( summarized in the table ) .
health benefits associated with fiber effects in the small bowel ( eg , cholesterol lowering , improved glycemic control , satiety , weight loss ) are a gel - dependent phenomenon , and the degree of benefit is proportional to the viscosity of the gelling fiber .
health benefits associated with fiber effects in the large bowel ( eg , relief from constipation , diarrhea , ibs ) will be discussed in detail in part 2 of this 2-part series . briefly , large bowel effects are derived from 2 mechanisms : an insoluble fiber provides a mechanical stimulus proportional to particle size ( eg , wheat bran softens hard stool in constipation but can exacerbate diarrhea and ibs ) and a nonfermented gel - forming fiber that remains intact / retains its high water - holding capacity throughout the large bowel can provide a stool - normalizing effect ( ie , psyllium softens hard stool in constipation , firms loose / liquid stool in diarrhea , normalizes stool form in ibs ) . when recommending a fiber supplement , only a soluble nonfermenting , gel - forming fiber has been clinically proven to provide all of the health benefits typically associated with a fiber supplement . | dietary fiber that is intrinsic and intact in fiber - rich foods ( eg , fruits , vegetables , legumes , whole grains ) is widely recognized to have beneficial effects on health when consumed at recommended levels ( 25 g / d for adult women , 38 g / d for adult men ) . most ( 90% ) of the us population does not consume this level of dietary fiber , averaging only 15 g / d . in an attempt to bridge this
fiber gap , many consumers are turning to fiber supplements , which are typically isolated from a single source .
fiber supplements can not be presumed to provide the health benefits that are associated with dietary fiber from whole foods . of the fiber supplements on the market today , only a minority possess the physical characteristics that underlie the mechanisms driving clinically meaningful health benefits .
the first part ( current issue ) of this 2-part series will focus on the 4 main characteristics of fiber supplements that drive clinical efficacy ( solubility , degree / rate of fermentation , viscosity , and gel formation ) , the 4 clinically meaningful designations that identify which health benefits are associated with specific fibers , and the gel - dependent mechanisms in the small bowel that drive specific health benefits ( eg , cholesterol lowering , improved glycemic control ) . the second part ( next issue ) of this 2-part series
will focus on the effects of fiber supplements in the large bowel , including the 2 mechanisms by which fiber prevents / relieves constipation ( insoluble mechanical irritant and soluble gel - dependent water - holding capacity ) , the gel - dependent mechanism for attenuating diarrhea and normalizing stool form in irritable bowel syndrome , and the combined large bowel / small bowel fiber effects for weight loss / maintenance .
the second part will also discuss how processing for marketed products can attenuate efficacy , why fiber supplements can cause gastrointestinal symptoms , and how to avoid symptoms for better long - term compliance . |
the twentieth century witnessed a technology revolution in medicine and health through instrumentation , computer and information and communication technologies .
this revolution has continued in the twenty - first century , with smart cross- and trans - disciplinary technologies and innovations directly impacting medical practice and healthcare delivery , which , in turn , have redefined the relationship between patients and healthcare providers .
technology innovations and globalization have brought the world together as one global community where developing and developed economies have become more dependent and well connected than in previous times .
as the overall life expectancy across the globe has increased , the global community is now facing new challenges of improving quality of life and healthcare at an affordable cost . while the exponentially rising cost of healthcare , defined as total healthcare expenditure as a percentage of a nation s gross domestic product ( gdp ) ,
is a critical priority challenge in developed nations , providing minimal quality healthcare to all , specifically large and sparsely distributed communities living in rural areas , is the most vital challenge to developing nations
. a necessary component of affordable global healthcare is point - of - care ( poc ) healthcare technologies , and developing poc technologies will require continuous evolution of innovation in smart and portable bio - sensor , computing , information and communication technologies .
a strategic study at the national institutes of health has noted ( http:// report.nih.gov/nihfactsheets/viewfactsheet.aspx?csid=112 ) : with the development of miniaturized devices and wireless communication , the way in which doctors care for patients will change dramatically and the role patients take in their own healthcare will increase .
healthcare will become more personalized through tailoring of interventions to individual patients . though the challenges of providing high - quality healthcare in developing countries are different than those in developed countries , they share a common goal : to provide access to health monitoring and assessment technologies to people with limited or no healthcare facilities , or with geographically distant or difficult to physically access facilities . while developed countries may find poc technologies an effective means for reducing healthcare costs and improving efficiency , poc technologies are critical in the provision of diagnostic and monitoring healthcare needs in countries with large populations or rural areas .
the developing countries in the eastern part of the globe , which account for more than two - thirds of the population of the world , face the basic challenge of providing minimal healthcare to all people living in adverse geographical or economic constraints , and also monitoring critical infectious diseases such as hiv / aids , tb , malaria , etc .
given the rapidly aging populations in both developed and developing nations , it is now more critical than ever to develop collaborative synergies to explore poc health monitoring , assessment and therapeutic technologies to significantly impact global healthcare for the well - being of a healthy society .
however , the implementation of poc healthcare technologies towards a tangible clinical impact poses formidable challenges in educating users .
not only must users and local support staff learn about technology usage , measurement techniques , data communication and compliance , patients and family members must undergo a behavioral change to understand and accept new roles and responsibilities in keeping themselves , family members , and others healthy .
the concept of self - care must be a major flagship in this education process .
poc healthcare technologies ( including sensor- and biomarkers - based poc diagnostic technologies ; therapeutic and rehabilitation devices ; and information and communication technology ( ict ) with mhealth , ehealth , and health monitoring with poc decision support systems ) will directly impact patients , support staff , community center workers , and nurses , among others .
all of these users will have to become comfortable , to varying degrees , with technology usage and local decision - making .
in addition , physicians and business managers will also need to become conversant in the broad spectrum of data integration , mining and interpretation .
the embs conference on point - of - care healthcare technologies invited scientific researchers and innovators , industry leaders , clinical experts , and policy makers from the usa , hong kong , china , japan , europe and india as plenary , keynote and panel speakers .
this white paper was developed out of those presentations , as well as panel discussions , data presented , and comments made during breakout sessions , using the following multi - step methodology .
the conference s first day featured plenary and keynote talks by leaders and representatives from government agencies including roderic pettigrew , md , phd , institute director , national institute of biomedical imaging and bioengineering , national institutes of health ( usa ) ; senior leaders from global industries including ibm life sciences and medtronic ( usa and india ) ; experts from clinical healthcare facilities including the cardiology department , kyushu university hospital ( japan ) and apollo hospital ( india ) ; and biomedical researchers and innovators .
these talks were followed by a panel discussion led by representatives from stakeholder groups from all over the globe .
both the plenary and keynote talks and the expert panel discussed current and future challenges in global healthcare . after these interactive panel discussions with over 176 researchers and stakeholders , the following steps were implemented to systematically collect insights from the various discussions generated by the conference program , including two additional panel discussions and three breakout sessions .
conference attendees represented a rich spectrum of clinical practitioners , industry experts and entrepreneurs , academic researchers , and policy makers ( table 1).table 1percentage of conference attendees representing major stakeholder groups.stakeholder representation typepercentageclinical practitioners27%industry representatives and entrepreneurs23%academic researchers and students35%policy makers , federal and funding agency representatives15% this paper represents the summary of discussions , data and comments made during the conference events .
1.a questionnaire was circulated after the first panel discussion to all attendees requesting them to identify specific issues for discussion during the breakout sessions at the conference .
these questions were categorized for three breakout sessions.2.three breakout sessions were held with detailed discussions on the following topics :
a.breakout session 1 : priority point - of - care healthcare technology areas and global collaborationsb.breakout session 2 : patient participation and role : expectation and challengesc.breakout session 3 : pocht implementation strategies and compliance : challenges and future trends3.breakout discussions were summarized by the session leaders in consultation with designated note - takers who transcribed the sessions and presented to the entire group of conference attendees in the panel discussion 2 : reports from breakout sessions : future trends and follow - up .
the discussions were summarized further in the raw data.4.the speakers from panel discussion 2 session formed a committee of authors and prepared a report that was transformed into the content of this paper .
the paper went through three iterations to help ensure that it was an accurate record of the conference and that all points of view were included .
a questionnaire was circulated after the first panel discussion to all attendees requesting them to identify specific issues for discussion during the breakout sessions at the conference .
three breakout sessions were held with detailed discussions on the following topics :
a.breakout session 1 : priority point - of - care healthcare technology areas and global collaborationsb.breakout session 2 : patient participation and role : expectation and challengesc.breakout session 3 : pocht implementation strategies and compliance : challenges and future trends breakout session 1 : priority point - of - care healthcare technology areas and global collaborations breakout session 2 : patient participation and role : expectation and challenges breakout session 3 : pocht implementation strategies and compliance : challenges and future trends breakout discussions were summarized by the session leaders in consultation with designated note - takers who transcribed the sessions and presented to the entire group of conference attendees in the panel discussion 2 : reports from breakout sessions : future trends and follow - up .
the speakers from panel discussion 2 session formed a committee of authors and prepared a report that was transformed into the content of this paper .
the paper went through three iterations to help ensure that it was an accurate record of the conference and that all points of view were included .
, such technologies do not exist in isolation and must be integrated into and adopted by new or existing health service delivery models , be supported by sound business cases , and show demonstrated levels of improvement to patient health outcomes in terms of such metrics as quality - adjusted life years ( qalys ) as a means of quantifying disease burden .
development , deployment and compliance issues related to affordable global healthcare have to be critically examined towards the creation of sound business models for their effective implementation such that they can be sustained with an economic impact .
what is striking about the concept of pocht is its near universality of potential application .
there is benefit to the management and treatment of most diseases hence priorities mirror the prevalence of disease in each country .
there is applicability to both wealthy and developing countries with cross - fertilization of design back and forth among all nations , with both simple and advanced technologies being of use to all . both rural and urban settings would benefit greatly from poc technologies .
perhaps most striking is the potential for widespread and localized screening for disease and health conditions . a simple vision of the technology might include :
( a)increasingly low - cost diagnostic tests , including those modified from existing methods through the use of novel , low - cost micro - molecular - biochemistry technology;(b)inexpensive device - based imaging and first - level analysis ( e.g. , smartphones capable of pulse oximetry , blood pressure , ekg recording and analysis or image recognition of skin disease);(c)smart device / smartphone / computer communication of data to regional or central health centers;(d)communication back to the personal care site for treatment or feedback;(e)ability to engage sophisticated healthcare treatment and diagnostic information , either by accessing human experts or clinical decision support systems . increasingly low - cost diagnostic tests , including those modified from existing methods through the use of novel , low - cost micro - molecular - biochemistry technology ; inexpensive device - based imaging and first - level analysis ( e.g. , smartphones capable of pulse oximetry , blood pressure , ekg recording and analysis or image recognition of skin disease ) ; smart device / smartphone / computer communication of data to regional or central health centers ; communication back to the personal care site for treatment or feedback ; ability to engage sophisticated healthcare treatment and diagnostic information , either by accessing human experts or clinical decision support systems .
within this broad framework there are many health areas that would potentially be impacted . some of the global needs and challenges include :
( a)chronic disease management and monitoring : here
, the major impact would come from the major chronic diseases , especially cardiovascular , pulmonary , neurological , geriatric , and early detection of the onset of and complications from diabetes.(b)therapeutic intervention : rehabilitation medicine and therapy would be greatly assisted by the ability to locally monitor patient progress , condition , and exercise or other health management programs . in rural areas where transport to a rehabilitation facility is prohibitive ,
the same logic applies in developed countries where system cost is an over - riding issue.(c)prenatal monitoring : special mention is made of the impact potential for pocht in perinatal care ; this would include routine physiological monitoring of hemoglobin , urine protein and blood pressure to detect problems at an early stage .
pocht could lead to major reductions in maternal mortality rate.(d)preventative medicine through behavioral change : there is a great potential for increased feedback to the individual of key health indicators .
one can imagine poor , rural areas where the introduction of paramedical personnel bringing more information coupled with simple monitoring measures of health ( blood pressure , heart rate , blood physiology ) would have significant impact on people s behavior and lives . at the other extreme ,
pocht technologies are already in the hands of wealthy , educated people in the form of smartphone applications for monitoring exercise there will be a continuing and rapid growth of monitoring capability for this population that already wants to change its behavior .
aggressive development either private , profit - making or government could bring these behavior - changing technologies to ever - wider populations , .(e)medical information : the ability to collect medical and healthcare information locally and aggregate centrally has strong implications for epidemiology and for planning the availability of medical supplies and resources ( supply - chain management ) .
a form of this already exists in the rfid of equipment for inventory within hospitals . chronic disease management and monitoring : here , the major impact would come from the major chronic diseases , especially cardiovascular , pulmonary , neurological , geriatric , and early detection of the onset of and complications from diabetes .
therapeutic intervention : rehabilitation medicine and therapy would be greatly assisted by the ability to locally monitor patient progress , condition , and exercise or other health management programs . in rural areas where transport to a rehabilitation facility is prohibitive ,
the same logic applies in developed countries where system cost is an over - riding issue .
prenatal monitoring : special mention is made of the impact potential for pocht in perinatal care ; this would include routine physiological monitoring of hemoglobin , urine protein and blood pressure to detect problems at an early stage .
preventative medicine through behavioral change : there is a great potential for increased feedback to the individual of key health indicators .
one can imagine poor , rural areas where the introduction of paramedical personnel bringing more information coupled with simple monitoring measures of health ( blood pressure , heart rate , blood physiology ) would have significant impact on people s behavior and lives .
at the other extreme , pocht technologies are already in the hands of wealthy , educated people in the form of smartphone applications for monitoring exercise there will be a continuing and rapid growth of monitoring capability for this population that already wants to change its behavior .
aggressive development either private , profit - making or government could bring these behavior - changing technologies to ever - wider populations , . medical information :
the ability to collect medical and healthcare information locally and aggregate centrally has strong implications for epidemiology and for planning the availability of medical supplies and resources ( supply - chain management ) .
a form of this already exists in the rfid of equipment for inventory within hospitals .
there is strong consensus that several technologies are already having a huge impact on society at large , with impacts on healthcare to follow .
( i)perhaps ubiquitous is the smartphone capable of a number of diagnostic measurements , including ekg / heart rate , breathing rate , blood pressure , blood oxygen saturation , image recognition for skin disease(ii)low cost blood chemistry sensors , ranging from the more straightforward ( blood glucose ) to the highly sophisticated ( detectors for dengue fever , on chip pcr)(iii)reduced - cost versions of historically expensive technologies an example is ultrasound machines whose cost now permits wide distribution(b)communications and computational technology : smartphones put more computer power in the hands of a common person than a computer engineer dreamed of 50 years ago .
the development of these technologies is practically for free as other markets are driving the cost and availability faster than the medical applications would .
the goal is to harness these technologies , not develop them.(c)modeling and simulation from physiology to behavior : as more point - of - care data become available , there will be increasing need for models of increasing complexity to assist in analysis .
an example is modeling the daily activity patterns of the elderly to predict medical problems .
more generally , the ability to use data to anticipate individual problems is a key component of personalized medicine.(d)automated decision - making and support : we have now seen more than a decade of on - line medical diagnostic information services , which will continue to grow in sophistication .
there is tremendous potential for exploiting the spectacular medical research knowledge base , advancing the practice of evidence - based medicine on a world wide scale .
the initial cost is very high , but the delivery cost is very low given the communications technology .
this technology can scale for the use of the expert , the general practitioner , the nurse , and the paramedical professional.(e)accessible data structures : the delivery of the benefits of pocth will be greatly assisted by enhanced accessibility of data to the broader medical community .
there are a variety of competing issues to achieving this goal , including security and privacy of data , interoperability of data structures , and ownership of data .
( i)perhaps ubiquitous is the smartphone capable of a number of diagnostic measurements , including ekg / heart rate , breathing rate , blood pressure , blood oxygen saturation , image recognition for skin disease(ii)low cost blood chemistry sensors , ranging from the more straightforward ( blood glucose ) to the highly sophisticated ( detectors for dengue fever , on chip pcr)(iii)reduced - cost versions of historically expensive technologies an example is ultrasound machines whose cost now permits wide distribution perhaps ubiquitous is the smartphone capable of a number of diagnostic measurements , including ekg / heart rate , breathing rate , blood pressure , blood oxygen saturation , image recognition for skin disease low cost blood chemistry sensors , ranging from the more straightforward ( blood glucose ) to the highly sophisticated ( detectors for dengue fever , on chip pcr ) reduced - cost versions of historically expensive technologies an example is ultrasound machines whose cost now permits wide distribution communications and computational technology : smartphones put more computer power in the hands of a common person than a computer engineer dreamed of 50 years ago .
the development of these technologies is practically for free as other markets are driving the cost and availability faster than the medical applications would .
modeling and simulation from physiology to behavior : as more point - of - care data become available , there will be increasing need for models of increasing complexity to assist in analysis .
an example is modeling the daily activity patterns of the elderly to predict medical problems .
more generally , the ability to use data to anticipate individual problems is a key component of personalized medicine .
automated decision - making and support : we have now seen more than a decade of on - line medical diagnostic information services , which will continue to grow in sophistication .
there is tremendous potential for exploiting the spectacular medical research knowledge base , advancing the practice of evidence - based medicine on a world wide scale .
the initial cost is very high , but the delivery cost is very low given the communications technology .
this technology can scale for the use of the expert , the general practitioner , the nurse , and the paramedical professional .
accessible data structures : the delivery of the benefits of pocth will be greatly assisted by enhanced accessibility of data to the broader medical community .
there are a variety of competing issues to achieving this goal , including security and privacy of data , interoperability of data structures , and ownership of data .
others will need support from governments , either directly through education as well as research and development funds , or indirectly by incentivizing the private sector .
( a)networking of practitioners : the encouragement of a growing leadership community is essential to the promulgation of pocht practice .
this should come in a variety of forms : publication in scholarly journals ; publication in the medical trade press ; workshops sponsored by national medical organizations ; conferences ; social media ; and moocs ( massive online open courseware ; http://www.mooc-list.com).(b)medical and paramedical education : pocht makes possible task shifting at all levels , putting expert knowledge in the hands of generalists and general medical knowledge in the hands of paramedical personnel
. there will be tremendous need for education at all levels.(c)design for all : this maxim implies that designing for the cost constraints of the developing world impacts medical products in the developed world , and vice versa .
this is especially relevant in the fast - developing pocht area and a world in which innovation travels the globe nearly instantly.(d)entrepreneurship and financial support : pocht is an especially open area for entrepreneurial development , as is evidenced by rapidly developing smartphone applications , tremendous spinoffs from biomolecular science , and strong support for global health from a variety of western institutions and foundations .
still , much more is needed from all sectors of society.(e)standards and harmonization : this refers to a host of properties that enable data access , storage , transmission and use ; standards for measurement and reporting of patient information ; and access to expert information and to one s own records .
networking of practitioners : the encouragement of a growing leadership community is essential to the promulgation of pocht practice .
this should come in a variety of forms : publication in scholarly journals ; publication in the medical trade press ; workshops sponsored by national medical organizations ; conferences ; social media ; and moocs ( massive online open courseware ; http://www.mooc-list.com ) . medical and paramedical education : pocht makes possible task shifting at all levels , putting expert knowledge in the hands of generalists and general medical knowledge in the hands of paramedical personnel .
design for all : this maxim implies that designing for the cost constraints of the developing world impacts medical products in the developed world , and vice versa .
this is especially relevant in the fast - developing pocht area and a world in which innovation travels the globe nearly instantly .
entrepreneurship and financial support : pocht is an especially open area for entrepreneurial development , as is evidenced by rapidly developing smartphone applications , tremendous spinoffs from biomolecular science , and strong support for global health from a variety of western institutions and foundations .
standards and harmonization : this refers to a host of properties that enable data access , storage , transmission and use ; standards for measurement and reporting of patient information ; and access to expert information and to one s own records .
clinical impact can be realized in preventive , therapeutic and surveillance areas . in the preventive area ,
for example , a decline in the incidence of myocardial infarction after good control of diabetes , cholesterol and blood pressure will take years to realize .
for example , the apollo hospital in india uses cardio biomarkers in early diagnosis of myocardial infarction and early transfer to the icu .
it can be readily shown that poct has a favorable impact on the hospital s cardiac mortality .
similarly , use of antenatal pocht kits in diagnosing early eclampsia or anemia can be easily shown to reduce maternal mortality rate .
surveillance pocht is similar to preventive pocht where the actual clinical impact may be appreciable only after a few years
. the major challenge would be in data acquisition , communication , and patient compliance , specifically in developing economies .
the major challenge is in task shifting : shift of preliminary or pre - diagnosis responsibility at the point - of - care .
other challenges include developing pathways to provide :
( a)evidence - based personalized care;(b)patient centered precision medicine;(c)preventive healthcare;(d)short - term feedback with long - term benefits;(e)cost - effectiveness , specifically in mass screening ( e.g. , diabetes and hypertension monitoring);(f)easy and intuitive devices and decision support systems . evidence - based personalized care ; patient centered precision medicine ; preventive healthcare ; short - term feedback with long - term benefits ; cost - effectiveness , specifically in mass screening ( e.g. , diabetes and hypertension monitoring ) ; easy and intuitive devices and decision support systems .
the medical devices and informational communication technologies at the point - of - care also face other societal challenges for acceptance and implementation .
these issues include diverse demographic and cultural backgrounds , and differences in needs due to geographical , social , and economic factors . while it makes sense to be patient - centric , empowering ptaients with point - of - care decision support systems raises concerns about legal liability and potential reduction in sensitivity .
it is not yet clear how poct can be used to integrate family members and physicians into one effective healthcare team .
though the challenges of providing high - quality healthcare in developing countries are different than those in developed countries , there is a common goal to provide access to health monitoring and assessment technologies to people with limited or no healthcare facilities .
large developing nations with fast economic growth such as india and china are committed to providing healthcare to all , but they still face major challenges in assessing rural and underserved patients healthcare needs and in providing them with timely quality healthcare at the point - of - care .
this is also a critical challenge in metropolitan areas where the hospital and primary healthcare facilities are overburdened .
major challenging priority areas where healthcare is most needed for people in india , as identified by who , are : hypertension and cardiac deaths , diabetes , cancers , women s health ( specifically child birth ) and infant mortality , and neurological disorders .
use of advanced point - of - care technologies , including wearable sensors , biomarkers , and mobile - communications - based education , along with health data collection and analysis , is a viable and affordable way to reach larger populations for better healthcare and compliance .
the impact on quality of life from better outreach , increased affordability of quality primary care , and increased patient compliance would be tremendously positive .
it is important to consider perspectives from all stakeholders , including patients , industry , healthcare providers , payers , policy makers and society as a whole ( fig .
, pocht technologies must address critical issues in patient privacy , data integrity and security on one hand , but also infrastructure support and policies on the other hand .
these infrastructure and policy supports will need to enable data and decision - support systems for all stakeholder groups in healthcare : patients at point - of - care , clinicians at healthcare facilities , and payers at the insurance or provider levels .
all of these stakeholder groups must be willing to accept the challenges and potential errors that might impact the sensitivity and specificity of healthcare processes .
in addition , clinicians and community members , such as community health workers , will need to help patients accept responsibility and accountability for their own health as they are empowered to address their health issues , illnesses , and preventive care in order to remain healthy .
thus patients , families , and communities will need to learn to think in new ways about the use of technology and how to responsibly monitor their health when applying poc healthcare technologies and decision - support systems .
the transformational change in defining new roles and responsibilities for patients has to come through patient - centered design , local solutions , and sensitive patient - education on poc benefits , such as significant cost - savings , reduced hospitalizations , and better personalized and preventive healthcare .
the outreach to patients for poc education and monitoring may incorporate specific innovative methods such as smartphone ict and incentives from healthcare providers , payers and government .
for example , many developing and developed countries are encouraging continuous monitoring of blood glucose and hypertension through innovative programs including educational camps and free or heavily discounted prices of monitoring systems .
of course , the economic aspects of such initiatives in developing countries can cause critical challenges in implementation involving social and political issues .
recent studies on the economic impact of using poc technologies in economically challenged nations presented in references summarize that these socio - economic and infrastructure challenges may at first overshadow the benefits of poc technologies . yet , in the long run , poc technologies with smart ict hold tremendous hope for sustainably managing resources and improving healthcare delivery in rural and developing nations . while the developed world provides quality healthcare
, growing expense is a universal concern , perhaps most acutely in the usa with the most expensive healthcare system in the world .
mutual collaborative efforts and networking in both developed and developing markets will allow opportunities to learn the best technologies , research , innovation , and best practices that lead to better and more affordable global solutions for quality healthcare . a collaborative meeting jointly hosted by nih and nsf with invited technology , industry , and business leaders in washington , dc to discuss resource development strategies ( e.g. , workshops ) on future collaborative research , clinical translation , and implementation infrastructure issues . develop a web portal supported by nih / nsf / embs as the resource for collaborative networking , research and development , research dissemination , workshop , and clinical translation information in pocht with active participation from academia , industry , corporate sector , hospitals , and healthcare provider facilities .
an annual meeting with leaders and all stakeholders in technology innovation , development , commercialization , implementation , and clinical acceptance ( including reimbursement ) sectors should be pursued with an emphasis on the development , follow - up , and evaluation of strategic goals and global milestones . | this paper summarizes the panel discussion at the ieee engineering in medicine and biology point - of - care healthcare technology conference ( pocht 2013 ) held in bangalore india from jan 1618 , 2013 .
modern medicine has witnessed interdisciplinary technology innovations in healthcare with a continuous growth in life expectancy across the globe .
however , there is also a growing global concern on the affordability of rapidly rising healthcare costs . to provide quality healthcare at reasonable costs
, there has to be a convergence of preventive , personalized , and precision medicine with the help of technology innovations across the entire spectrum of point - of - care ( poc ) to critical care at hospitals . the first ieee embs special topic pocht conference held in bangalore , india provided an international forum with clinicians , healthcare providers , industry experts , innovators , researchers , and students to define clinical needs and technology solutions toward commercialization and translation to clinical applications across different environments and infrastructures .
this paper presents a summary of discussions that took place during the keynote presentations , panel discussions , and breakout sessions on needs , challenges , and technology innovations in poc technologies toward improving global healthcare .
also presented is an overview of challenges and trends in developing and developed economies with respect to priority clinical needs , technology innovations in medical devices , translational engineering , information and communication technologies , infrastructure support , and patient and clinician acceptance of poc healthcare technologies . |
a 48 years old saudi male presented to the emergency department with shortness of breath , persistent low grade fever and easy bruising for 3 days .
the patient also complained of progressive weakness , loss of appetite for 2 months duration and had lost 7 kg of weight over the last 2 months .
his family or medical history was unremarkable and was not receiving any medical treatment for any chronic illness .
he was a heavy smoker consuming two packs of cigarettes daily for several years and had long history of heavy alcohol abuse .
he denied any drug abuse or toxin exposure . on physical examination ; he was pale , had multiple bruises particularly on the lower limbs and his body temperature was 38.2c .
g / l ) , red blood cells ( rbc ) 2.1510/l ( 4.2 - 5.510/l ) , mean corpuscular volume 88 fl ( 78 - 97 fl ) and mean corpuscular hemoglobin 28 pg ( 27 - 32 pg ) .
leukocytes were 2.0110/l with 3% blasts , myelocytes 3% , neutrophils 19% , monocytes 8% , basophils 1% and 67% lymphocytes .
biochemical markers revealed elevated serum levels of lactate dehydrogenase ( ldh ) , uric acid and total bilirubin .
peripheral smear showed marked anisopoikilocytosis with schistocytes , basophilic stippling , spherocytes , many nucleated rbc and rare circulating blasts .
erythroid precursors showed significant dysplastic changes with nuclear irregularities , budding and bi - nucleation while neutrophil morphology was essentially normal .
the circulating blasts were medium to large blasts with round nuclei , fine chromatin , prominent nucleoli and deep blue a granular cytoplasm without auer rods .
the bone marrow aspirate yielded a markedly hypercellular bone marrow essentially replaced by erythroid precursors , representing approximately 87% of the marrow cells .
the erythroid precursors displayed dysplastic morphology , including multi - nucleation , nuclear budding and megaloblastoid changes .
periodic acid schiff ( pas ) stain revealed globular and block - like positivity in many abnormal erythroblasts .
perls perl s stain showed a few sideroblasts ; however no ringed sideroblasts were observed .
flow cytometry analysis of the bone marrow aspirate revealed many immature cells which were positive for cd71 , glycophorin a and partially positive for cd36 , consistent with erythroid precursors .
staining for cd13 , cd33 , cd34 , cd41 , cd61 and all other myeloid and lymphoid makers was negative .
the bone marrow biopsy revealed a hypercellular packed marrow with monotonous leukemic infiltrate composed of primitive looking blasts .
the infiltrating blasts had scant cytoplasm , high nuclear to cytoplasmic ratio , round nucleus with fine chromatin and 1 - 2 prominent nucleoli ( figure 1 ) .
immunohistochemistry revealed strong positivity to e - cadherin ( ech-6 ; ventana medical systems , inc . ,
roche , basel , switzerland ) , weak positivity for glycophorin a ( ga - r2 ; ventana medical systems , inc . ) and negative for cd34 , mpo , vwf , cd3 and cd79a .
these morphological and immunophenotypic findings supported the diagnosis of pure erythroid leukemia ( pel ) fab subtype m6b .
cytogenetics analysis was performed on 20 metaphases and detected a complex karyotype with multiple chromosomal aberrations ( figure 2 ) :
46 - 48,xy , add(4)(q ? ) del(4)(p?),del(5)(q23),add(6)(p 23),del(7)(q22 ) , t(8;9)(p11.2;q12),+del(9)(q22),de l(18)(q21 ) the patient was treated with a standard induction ( 7 + 3 ) chemotherapy regimen consisting of daunorubicin 45 mg / m daily for 3 days and cytarabine 100 mg / m daily continuous infusion for 7 days .
blood and platelet transfusions were administered during induction period . on post - induction day 28 , the bone marrow biopsy showed hypercellular marrow with 38% residual erythroblasts .
he was re - inducted again with flag regimen ( fludarabine + high - dose cytarabine + g - csf ) .
he failed to tolerate the treatment and died after 10 days due to severe pulmonary infection .
a 48 years old saudi male presented to the emergency department with shortness of breath , persistent low grade fever and easy bruising for 3 days .
the patient also complained of progressive weakness , loss of appetite for 2 months duration and had lost 7 kg of weight over the last 2 months .
his family or medical history was unremarkable and was not receiving any medical treatment for any chronic illness .
he was a heavy smoker consuming two packs of cigarettes daily for several years and had long history of heavy alcohol abuse .
he denied any drug abuse or toxin exposure . on physical examination ; he was pale , had multiple bruises particularly on the lower limbs and his body temperature was 38.2c .
g / l ) , red blood cells ( rbc ) 2.1510/l ( 4.2 - 5.510/l ) , mean corpuscular volume 88 fl ( 78 - 97 fl ) and mean corpuscular hemoglobin 28 pg ( 27 - 32 pg ) . leukocytes were 2.0110/l with 3% blasts , myelocytes 3% , neutrophils 19% , monocytes 8% , basophils 1% and 67% lymphocytes . platelet count was 2310/l ( 140 - 45010/l ) .
biochemical markers revealed elevated serum levels of lactate dehydrogenase ( ldh ) , uric acid and total bilirubin .
peripheral smear showed marked anisopoikilocytosis with schistocytes , basophilic stippling , spherocytes , many nucleated rbc and rare circulating blasts .
erythroid precursors showed significant dysplastic changes with nuclear irregularities , budding and bi - nucleation while neutrophil morphology was essentially normal .
the circulating blasts were medium to large blasts with round nuclei , fine chromatin , prominent nucleoli and deep blue a granular cytoplasm without auer rods .
the bone marrow aspirate yielded a markedly hypercellular bone marrow essentially replaced by erythroid precursors , representing approximately 87% of the marrow cells .
the erythroid precursors displayed dysplastic morphology , including multi - nucleation , nuclear budding and megaloblastoid changes .
periodic acid schiff ( pas ) stain revealed globular and block - like positivity in many abnormal erythroblasts .
perls perl s stain showed a few sideroblasts ; however no ringed sideroblasts were observed .
flow cytometry analysis of the bone marrow aspirate revealed many immature cells which were positive for cd71 , glycophorin a and partially positive for cd36 , consistent with erythroid precursors . staining for cd13 , cd33 , cd34 , cd41 , cd61 and
the bone marrow biopsy revealed a hypercellular packed marrow with monotonous leukemic infiltrate composed of primitive looking blasts .
the infiltrating blasts had scant cytoplasm , high nuclear to cytoplasmic ratio , round nucleus with fine chromatin and 1 - 2 prominent nucleoli ( figure 1 ) .
immunohistochemistry revealed strong positivity to e - cadherin ( ech-6 ; ventana medical systems , inc . ,
roche , basel , switzerland ) , weak positivity for glycophorin a ( ga - r2 ; ventana medical systems , inc . ) and negative for cd34 , mpo , vwf , cd3 and cd79a .
these morphological and immunophenotypic findings supported the diagnosis of pure erythroid leukemia ( pel ) fab subtype m6b .
cytogenetics analysis was performed on 20 metaphases and detected a complex karyotype with multiple chromosomal aberrations ( figure 2 ) :
46 - 48,xy , add(4)(q ? ) del(4)(p?),del(5)(q23),add(6)(p 23),del(7)(q22 ) , t(8;9)(p11.2;q12),+del(9)(q22),de l(18)(q21 )
the patient was treated with a standard induction ( 7 + 3 ) chemotherapy regimen consisting of daunorubicin 45 mg / m daily for 3 days and cytarabine 100 mg / m daily continuous infusion for 7 days . blood and
he was re - inducted again with flag regimen ( fludarabine + high - dose cytarabine + g - csf ) .
he failed to tolerate the treatment and died after 10 days due to severe pulmonary infection .
pure erythroid leukemia is exceedingly rare type of aml representing < 1% of all aml cases and 13% of acute erythroid leukemia cases .
it is a neoplastic proliferation of immature cells committed exclusively to the erythroid lineage comprising at least 80% of bone marrow cells with no evidence of a significant myeloblastic component .
clinically , pel patients present usually with profound anemia symptoms such as weakness and pallor , fever and hemorrhages .
there are few reported cases of extramedullary pure erythroid leukemia involving lymph nodes or presenting as a hemangioma .
our patient presented with pel post heavy alcohol abuse over a prolonged time period that may indicate presence of some kind of causal relationship , an observation consistent with previous reports .
because of the extreme rarity of pel , few studies have examined its pathogenesis and genetic features .
. however , rare cases of de novo familial pel , being autosomal dominant , have been reported .
a number of available studies have revealed complex karyotype with predominance of -5/del(5q ) , -7/del(7q ) and + 19p . in a study conducted by liu et al .
, all pel patients ( n=16 ) showed an extremely complex karyotype , with a median of 12 abnormalities ( range 3 - 37 ) .
these abnormalities most frequently involved chromosomes 5 ( 69% ) , 7 ( 56% ) , 17 ( 44% ) , and 19 ( 38% ) .
cytogenetic study for the present patient revealed an extreme complex karyotype with 8 chromosomal abnormalities . beside the most commonly reported abnormalities , such as del(5q ) and
del(7q ) , our patient had a novel translocation t(8;9)(p11.2;q12 ) in all the examined metaphases .
to the best of our knowledge , this translocation has never been reported in acute myeloid leukemia in the past .
unfortunately , we were not able to perform a higher molecular study in order to clarify the origin of this abnormality .
diagnosis of pel requires multiparameter approach including detailed clinical history , peripheral blood and bone marrow examination , immunophenotyping and genetic studies as well .
the present case also showed pancytopenia with 3% circulating blasts in the peripheral blood . in bone marrow aspirate ,
the majority of cells ( > 80% ) are erythroid precursors with marked left shift and increased proerythroblasts . proerythroblasts - the most immature recognizable erythroid precursors- are medium to large blasts with round nuclei , fine chromatin , occasional prominent nucleoli , deep blue agranular cytoplasm with variable cytoplasmic vacuolization and no auer rods .
periodic acid - schiff ( pas ) cytochemical staining is commonly positive , often in cytoplasmic vacuoles in a block - like pattern , while mpo , sudan black , and chloroacetate esterase are characteristically negative .
core biopsy is usually markedly hypercellular and shows erythroid predominance with sheets of immature cells clearly demonstrating a leukemic infiltrative pattern .
erythroblasts usually express cd71 ( transferrin receptor ) , but occasionally cd71 expression can be aberrantly dim .
these cells variably express hemoglobin a , glycophorin a , abh blood group antigens , and hla - dr .
. the gerbich blood group ( gero ) antibody , carbonic anhydrase1 , and cd36 can be expressed by more immature erythroblast .
immunophenotyping of the present case revealed many immature cells which were positive for cd71 , glycophorin a and partially positive for cd36 , consistent with erythroid precursors .
various markers including glycophorin a , b , and c , hemoglobin , cd36 , and spectrin have been used to identify immature erythroblasts in pel ; however , the results either lack consistency or specificity .
e - cadherin is a cell adhesion molecule involved in the morphogenesis of multicellular organisms and maintenance of solid tissues .
it is a selective marker of immature erythroblasts and is down regulated during erythroid maturation . in the bone marrow , its expression appears to be limited to erythroid lineage , and mainly in immature erythroblasts . in the present patient ,
e - cadherin immunohistochemistry stain revealed strong positivity ( 80% ) while glycophorine glycophorin a was weak positive ( 20 ) which was in agreement with the published data .
differential diagnosis of pel is broad , and includes both non - neoplastic and neoplastic conditions .
erythroid hyperplasia may result from ineffective erythropoiesis such as congenital dyserythropoietic anemia , hemolytic anemia , vitamin b12/folate deficiency , infection , or autoimmune hemolysis .
even marked dyserythropoiesis can be seen in floridly reactive conditions potentially mimicking a myeloid neoplasm .
pure erythroid leukemia needs also , to be distinguished from other forms of myeloid neoplasms with erythroid predominance namely therapy related ( t - aml ) , acute myeloid leukemia with myelodysplasia related changes ( aml - mrc ) , aml with recurrent cytogenetic abnormalities and myelodysplastic syndrome .
cases that do not fit into any of the above well - defined categories are classified as amlnos , further subcategorized by their morphologic and immunophenotypic characteristics .
pure erythroid leukemia without morphologic evidence of erythroid maturation may be difficult to be distinguished from other types of aml , particularly megakaryoblastic leukemia , and also from acute lymphoblastic leukemia and lymphoma .
the median survival is 3.6 months compared with 28 months in acute erythroid / myeloid leukemia .
the standard induction for pel is ( 7 + 3 ) chemotherapy regimen , consisting of daunorubicin 45 mg / m daily for 3 days and cytarabine 100
mg / m daily continuous infusion for 7 days ; which offers a complete remission ( cr ) rate of approximately 10 - 40% ; if cr is obtained , it is usually brief .
the response to chemotherapy and the length of survival is dependent on several factors such as cytogenetics and karyotype abnormality and patient comobidities .
the median survival is 3.6 months compared with 28 months in acute erythroid / myeloid leukemia .
the standard induction for pel is ( 7 + 3 ) chemotherapy regimen , consisting of daunorubicin 45 mg / m daily for 3 days and cytarabine 100 mg / m daily continuous infusion for 7 days ; which offers a complete remission ( cr ) rate of approximately 10 - 40% ; if cr is obtained , it is usually brief .
the response to chemotherapy and the length of survival is dependent on several factors such as cytogenetics and karyotype abnormality and patient comobidities . | pure erythroid leukemia ( pel ) is rare hematopoietic neoplasm characterized by uncontrolled proliferation of immature erythroid precursors mainly abnormal proery - throblasts comprising at least 80% of bone marrow cells . in this paper ,
i present a case of 48 years old patient , who presented with pancytopenia and circulating erythroblast in peripheral blood after long history of alcohol abuse .
bone marrow examination revealed hypercellular marrow which is markedly infiltrated with immature erythroid precursors .
an expanded panel of immunophenotyping markers has confirmed the diagnosis of pel .
cytogenetics analysis detected a complex karyotype with multiple chromosomal abnormalities and a novel translocation , t(8;9 ) ( p11.2;q12 ) , which has not been reported in acute myeloid leukemia ( aml ) in the past .
the patient was treated with standard aml chemotherapy but he did not show an optimal response and passed away . an updated and short review about various aspects of pel has been made with special focus on immunophenotyping and genetic studies . |
cystoscopic evaluation of the lower urinary tract is a vital part of an office - based urologic practice .
however , regular surveillance cystoscopy is a significant source of morbidity for patients , and therefore attempts have been made to minimize discomfort secondary to this procedure .
flexible cystoscopy was first introduced in 1973 as a potentially less painful technique and has since become routine , particularly in men .
the current american urological association guidelines on the evaluation of microscopic hematuria recommend cystoscopy in appropriate individuals and report flexible cystoscopy to be associated with less pain or fewer postprocedure complications . as expected , most of the initial studies concerning flexible cystoscopy involved men .
the purpose of our study was to compare tolerability of rigid versus flexible cystoscopy in women .
we performed a randomized , single - blind , prospective study comparing tolerability of flexible versus rigid cystoscopy in women in an out - patient clinic setting at the university of wisconsin - madison . with full irb approval ,
women 18 years of age and older were randomized in a patient - blinded manner to rigid or flexible cystoscopy .
patients were approached to participate in the study at the time of cystoscopy , and informed consent was obtained .
indications for cystoscopy included hematuria , recurrent urinary tract infections , surveillance for cancer , and voiding difficulties .
all procedures were performed with the patient in the dorsal lithotomy position with the same sterile preparation utilizing 2% lidocaine jelly urethral instillation as a local anesthetic .
the olympus cyf type v2 flexible cystoscope and acmi m3 series gold rigid cystoscope were utilized in this study .
questionnaires were completed just prior to the procedure , immediately after the procedure , and one week later .
these addressed pain and the location of pain before , during , and after the procedure rated on a 10-point ( 10-cm ) visual analog scale ( vas ) ( figure 1 ) .
women who had previously had rigid cystoscopy performed were also asked whether they preferred the current technique or the previous rigid technique .
questionnaires obtained one week later addressed duration of symptoms of hematuria , dysuria , and urinary frequency .
patients were asked to retrospectively rate their discomfort during the procedure and were also asked whether they had contacted any health providers due to concerns after the procedure .
physicians also completed a form evaluating their success at visualizing the bladder completely , listing which scopes where used , and rating the level of difficulty of using the scopes on a 5-point scale with higher numbers representing more complexity .
results were analyzed by using wilcoxon rank sums and fisher 's exact test with sas statistical software version 9 ( sas institute inc . , cary , nc ) .
thirty - six women were randomized to rigid ( 18 ) or flexible ( 18 ) cystoscopy .
median discomfort of those patients experiencing pain during flexible and rigid cystoscopy was 1.4 and 1.8 , respectively ( p=0.39 , wilcoxon ) .
median recall of pain 1 week later was 0.8 and 1.15 ( p=0.37 , wilcoxon ) . in terms of peri - procedural pain
the overall average pain scores before , during , and after cystoscopy on vas were 0.33 , 1.0 , 0.47 , and 0.16 , 1.71 , 0.67 in patients undergoing flexible versus rigid cystoscopy , respectively .
average pain scores for those patients actually reporting discomfort associated with the procedure are shown in table 2 .
the average duration of dysuria , hematuria , and frequency amounted to less than a day in both groups , and these differences were not significant when comparing rigid and flexible cystoscopy ( table 3 ) .
average ease of examination ( on a 5-point scale ) as rated by physicians was 1.78 for flexible scopes and 1.65 for rigid scopes ( p=0.61 , wilcoxon ) .
cytology was obtained at the time of cystoscopy in 9 ( flexible ) and 11 ( rigid ) patients and was normal in all cases .
indications for cystoscopy patients reporting pain before , during , and after cystoscopy and recall of pain during the procedure on a questionnaire one week later average duration ( in days ) of patients reporting symptoms of dysuria , hematuria , frequency , or all of these although representing a small group , 10 of the patients who had flexible cystoscopy performed had previously had rigid cystoscopy . among these patients ,
the remainder either noted no difference between techniques ( 5 ) or preferred flexible cystoscopy ( 4 ) .
office cystoscopy was utilized in the present study to survey the bladder for a variety of indications , most commonly hematuria and recurrent urinary tract infections .
symptoms of dysuria , hematuria , and voiding difficulty following cystoscopy can last several days . while alternatives to cystoscopy such as urinary markers continue to be developed , a recent study indicates that patients are reluctant to forego cystoscopy without tests with 95% accuracy or better , such that cystoscopy remains an important surveillance tool . although it is anticipated that less invasive modalities will gain wider acceptance , it is important to evaluate methods of minimizing morbidity related to office cystoscopy .
prior studies evaluating flexible and rigid cystoscopy have focused on complications , tolerability , and effectiveness .
earlier comparisons revealed male patients preferred flexible cystoscopy in the clinic rather than rigid cystoscopy in the operating room with general anesthesia .
our current study is unique in that our data were obtained in the form of a randomized , patient - blinded trial in an attempt to minimize bias .
furthermore , this study is the first to focus on tolerability of cystoscopy in women in the outpatient ambulatory setting .
overall , both techniques are well tolerated by women with pain scores of 1.4 versus 1.8 out of 10 for flexible and rigid cystoscopy respectively .
in contrast , flexible cystoscopy in men is better tolerated than rigid cystoscopy , presumably due to urethral length and the angle required to inspect the bladder . in general , excellent tolerability was noted with both techniques with the majority of women reporting minimal discomfort on the vas .
60% of women reported pain less than 2 on a vas when evaluated after flexible cystoscopy .
it should be noted that most of the patients in this study [ 14/22 ( 61% ) ] had previously undergone cystoscopy , which may have affected their perception of discomfort .
it is noteworthy that only 1 out of 10 patients undergoing flexible cystoscopy with previous rigid cystoscopy experience actually preferred rigid cystoscopy , whereas 4 preferred flexible cystoscopy and 5 had no preference .
furthermore , with flexible cystoscopy , women may be positioned supine in a frog - leg position which could be advantageous in the office setting .
as has been shown previously , performing cystoscopy with the patient in the supine position can decrease preparatory and procedural time . because differences in positioning could potentially influence perceptions of pain or discomfort , in our study cystoscopy was performed with the patient in the dorsal lithotomy position to avoid any potential bias in this regard and to maintain blinding for both flexible and rigid techniques .
this study was not actually designed to evaluate time elapsed in cystoscopy , although it may follow that with the use of 1 scope as opposed to 2 , the flexible procedure may be faster .
this study was also not designed to evaluate the role of local anesthetic in cystoscopy , given recent studies including a metaanalysis of 9 randomized trials indicating no difference in pain perception in patients with local anesthetic versus sterile lubricant alone .
in addition to technique , several other aspects of office cystoscopy have been evaluated in relation to patient discomfort , which could potentially confound our findings .
for instance , administration of midazolam has been found to be effective in lessening patient discomfort . in this randomized trial , patients were divided into groups in which either flexible or rigid cystoscopy was performed in men and women , although the trial , designed to determine the effectiveness of midazolam , did not directly address flexible versus rigid cystoscopy .
another factor that may be significant in affecting patient discomfort is whether patients can observe the monitor during cystoscopy .
patient age has also been cited as an important factor in that older patients are generally better able to tolerate cystoscopy .
although patient preparation and maintenance costs for rigid and flexible cystoscopy are similar , the purchase price for rigid cystoscopes can be 2 to 3 times less than that for flexible cystoscopes .
both flexible and rigid cystoscopes are well tolerated by women . although a benefit for men may be noted with flexible cystoscopy , either the flexible or rigid technique may be used with a comparable pain tolerance and ease of use in women . | purpose : previous studies have evaluated the tolerability of rigid versus flexible cystoscopy in men . similar studies , however , have not been performed in women . we sought to determine whether office - based flexible cystoscopy was better tolerated than rigid cystoscopy in women.materials and methods : following full irb approval , women were prospectively randomized in a single - blind manner .
patients were randomized to flexible or rigid cystoscopy and draped in the lithotomy position to maintain blinding of the study .
questionnaires evaluated discomfort before , during , and after cystoscopy.results:thirty-six women were randomized to flexible ( 18 ) or rigid ( 18 ) cystoscopy . indications were surveillance ( 16 ) , hematuria ( 15 ) , recurrent utis ( 2 ) , voiding dysfunction ( 1 ) , and other ( 2 ) .
all questionnaires were returned by 31/36 women . using a 10-point visual analog scale ( vas ) , median discomfort during the procedure for flexible and rigid cystoscopy were 1.4 and 1.8 , respectively , in patients perceiving pain .
median recalled pain 1 week later was similar at 0.8 and 1.15 , respectively . none of these differences were statistically significant.conclusions:flexible and rigid cystoscopy are well tolerated in women .
discomfort during and after the procedure is minimal in both groups .
urologists should perform either procedure in women based on their preference and skill level . |
soft tissue sarcomas belong to a rare type of malignant tumors deriving from connective tissue and orginating mainly from mesodermal germ layer .
retroperitoneal sarcoma ( rs ) constitute for approximately 0,4% of all malignant tumors , which is about 15% of all sarcoma localizations .
the retroperitoneal space is very difficult for physical evaluation , mainly because the rs develops asymptomatically thus attaining large size and is often detected accidentally during an examination of different matter .
surgery is the sole treatment modality that may lead to total cure of this type of tumor .
obtaining microscopic tumor - free radical margin restricts complicated anatomic issues , lack of anatomic compartments , asymptomatic growth of the tumor and its large size , frequent infiltration and proximity of the vital organs . to reach the appropriate surgery margin without removal of the sarcoma in one piece with an adjacent organ
furthermore , during treatment of local recurrences the radical approach is possible in 60 - 70% of all cases with first or consecutive tumor recurrence [ 25 ] .
the resection of adjacent organs is generally well - founded because of its technical rationale in radical surgery , rather than actual infiltration of the organ .
jacques et al . had shown the actual infiltration of kidney parenchyma in 2 out of 30 nephrectomies .
the nci analysis conducted in 1975 demonstrated that patients with retroperitoneal sarcoma tend to experience local recurrences with intraperitoneal dissemination rather than create metastases beyond abdomen cavity .
the time of local recurrence is similar in all conducted analyses : cantin et al .
presented in their publication that 80% of local recurrences occurred within 2 years , simon and ennecking
80% of local recurrences within 2 years and 100% of local recurrences in 3 years , whereas shiu et al
adjuvant radiotherapy is a standard procedure for extremities and integument sarcomas patients treated with radical surgery . in patients with extremities sarcoma the dose of the whole postoperative radiation field exceeds 60 gy ( 60 - 80 gy ) .
tepper et al . showed excellent improvement of the local control in case of applying a dose level more than 60 gy as compared to the dose below 50 gy .
presented data that after application of a dose > 55 gy the local control rate was 72% , while after dose < 55 gy the local control was 38% .
applications of such doses are usually impossible in case of retroperitoneal sarcomas due to possible complications and difficult anatomic relations . in localization of retroperitoneal sarcomas a lot of critical organs are found : intestines , kidneys , liver and spinal cord .
ebrt in high doses considerably increases serious complications , so the dose in retroperitoneal space rarely exceeds 45 - 50 gy which is recognized as a well tolerated dose [ 16 , 17 ] .
this explains the importance of combined treatment ( surgery / radiotherapy ) in order to achieve good local control .
based on the results and taking into consideration difficulties in achieving the accurate surgery margins and high percentage of local recurrences in retroperitoneal sarcomas , determine the use of adjuvant radiotherapy in the case of retroperitoneal sarcomas also .
the idea of interstitial irradiation is to deliver a high dose rate dose ( hdr ) directly into tumor tissues or to the site of removed tumor which increases of the therapeutic index without the necessity of exposing the organ at risk due to ebrt complications . in treatment of retroperitoneal sarcomas ,
the range of radiation doses used in different centers of the world is quite large and differ from 8,75 to 30 gy , however doses used in most of the centers vary from 10 to 20 gy [ 1723 ] .
the data relates to cases with previous application of ebrt or planned postoperative adjuvant radiotherapy .
the aim of this work was to evaluate the effectiveness of combined treatment ( surgery + iobrt / ebrt ) , complications of this type of treatment , results of overall survival rate and local recurrence rate in retroperitoneal sarcoma patients .
in 1998 department of soft tissue / bone sarcoma ( dstbs ) , cancer center and institute of oncology started a prospective study about the estimation of possibilities and results for intraoperative brachytherapy ( iobrt ) after radical surgery of retroperitoneal sarcoma . in 2000
the centre started a treatment with the use of additional adjuvant ebrt for patients treated with combined treatment ( surgery / intraoperative brachytherapy ) .
the treatment protocol of the study was accepted by bioethics committee of m. sklodowska - curie cancer center and institute of oncology in warsaw . before entering the trial ,
every patient was obliged to give his written consent for participation in the study . from june 1998 to september 2006 , 84 retroperitoneal sarcoma patients were qualified for combined treatment ( surgery + iobrt ) .
retroperitoneal sarcoma was confirmed in all 84 patients by obtaining histopathology results , ct scan , x - ray , abdomen cavity and pelvis mri .
the age ranged from 17 - 78 ( median 50 ) : 17 - 75 for women ( median 51 ) , 22 - 78 for man ( median 49 ) . in the whole group of patients only 19 ( 22.6% ) of cases with retroperitoneal sarcoma were previously diagnosed and primarily treated at the institute of oncology .
the remaining 77.4% experienced recurrences of retroperitoneal sarcoma and were operated ( sometimes even several times ) in other centers and eventually guided to dstbs .
the largest diameter of most treated tumors ( 94.1% ) exceeded 5 cm ( range 4 - 23 cm ; median tumor size 15 cm ) ( fig .
the majority of sarcomas were with intermediate and high histological malignance grade ( g2 , g3 76.2% ) , the most common type of sarcomas were liposarcoma 46 cases ( 54.8% ) and leiomyosarcoma 11 patients ( 13.1% ) .
ct scan of retroperitoneal sarcoma prepared for ebrt planning and extent of surgery ( tumor and left kidney , tumor outlined in red line ) hdr units : gammamed 12i and microselectron were used for intraoperative irradiation .
iridium 192 was used with nominal activity 10 ci , applied through ham ( harrison anderson mick ) flap applicator .
the treatment planning was done with the use of abacus 3.0 treatment planning system ( earlier , version 1.6 was used instead ) on a 3d platform .
the range of therapeutic beam penetration was set on the basis of intraoperative radiologic test that did not exceed 1 cm from the applicator surface .
the single dose of 20 gy was delivered to the treatment volume with 1 cm margins ( figs . 2 and 3 ) . in case of insufficient hemodynamic parameters such as high amount of blood loss ,
the abdominal cavity was closed , but packing ( cotton cloth ) was placed on location were organ removal occurred and triggered ambiguous homeostasis .
, the additional postoperative ebrt radiation after iobrt was applied meanly after 30 days from combined retroperitoneal sarcomas / iobrt surgery .
ebrt planned dose of site and postoperative scar was 50 gy in 1.8 gy fractions .
a ) 3d image of ham applicator position , b ) dose distribution and ham applicators location the clinical and pathological parameters examined for prognostic value within the group undergoing iobrt were tumor size ( divided into two groups : < 10 and > 10 cm ) , histological malignancy grade of tumor ( low grade g1 vs. high grade g2 or g3 ) , histological tumor type ( liposarcoma vs. others ) , sex , one - time resection with a contiguous organ ( zero additional organs , one organ , and more than one organ ) , number of previous operations ( zero , one , or more than one ) , and subsequent ebrt .
we did not include the microscopic status of resection margins r0 vs. r1 in this analysis , because the probability of reliable estimation found mostly in recurrent retroperitoneal sarcomas is doubtful .
postoperative follow - up consisted of physical examination and routine imaging investigations such as computed tomography and ultrasonography of the abdominal cavity as well as chest x - ray / x - rays .
observations were assessed and analyzed every 3 months for the first 2 years , then in the 3 to 5 year period every 6 months , and annually thereafter .
the median follow - up time was 40 months for survivors ( range : 8 - 100 months ) and for iobrt patients 39 months ( range : 8 - 82 months ) .
overall survival ( os ) time was calculated from the date of operation at the study institution to the date of the most recent follow- up or death . the local recurrence free survival ( lrfs )
time was estimated from the date of retroperitoneal sarcoma excision to the date of the most recent follow up or local retroperitoneal sarcomas recurrence . for prospective data collection ,
statistical analysis was performed using statistica software ( statsoft , tulsa , ok ) . in univariate analysis survival rate
was assessed using the kaplan - meier method in combination with the log - rank test .
multivariate analysis for overall survival was performed with the use of proportional hazard cox regression model .
in 1998 department of soft tissue / bone sarcoma ( dstbs ) , cancer center and institute of oncology started a prospective study about the estimation of possibilities and results for intraoperative brachytherapy ( iobrt ) after radical surgery of retroperitoneal sarcoma . in 2000
the centre started a treatment with the use of additional adjuvant ebrt for patients treated with combined treatment ( surgery / intraoperative brachytherapy ) .
the treatment protocol of the study was accepted by bioethics committee of m. sklodowska - curie cancer center and institute of oncology in warsaw . before entering the trial ,
every patient was obliged to give his written consent for participation in the study . from june 1998 to september 2006 , 84 retroperitoneal sarcoma patients were qualified for combined treatment ( surgery + iobrt ) .
retroperitoneal sarcoma was confirmed in all 84 patients by obtaining histopathology results , ct scan , x - ray , abdomen cavity and pelvis mri .
the age ranged from 17 - 78 ( median 50 ) : 17 - 75 for women ( median 51 ) , 22 - 78 for man ( median 49 ) . in the whole group of patients only 19 ( 22.6% ) of cases with retroperitoneal sarcoma were previously diagnosed and primarily treated at the institute of oncology .
the remaining 77.4% experienced recurrences of retroperitoneal sarcoma and were operated ( sometimes even several times ) in other centers and eventually guided to dstbs .
the largest diameter of most treated tumors ( 94.1% ) exceeded 5 cm ( range 4 - 23 cm ; median tumor size 15 cm ) ( fig .
the majority of sarcomas were with intermediate and high histological malignance grade ( g2 , g3 76.2% ) , the most common type of sarcomas were liposarcoma 46 cases ( 54.8% ) and leiomyosarcoma 11 patients ( 13.1% ) .
ct scan of retroperitoneal sarcoma prepared for ebrt planning and extent of surgery ( tumor and left kidney , tumor outlined in red line )
iridium 192 was used with nominal activity 10 ci , applied through ham ( harrison anderson mick ) flap applicator .
the treatment planning was done with the use of abacus 3.0 treatment planning system ( earlier , version 1.6 was used instead ) on a 3d platform .
the range of therapeutic beam penetration was set on the basis of intraoperative radiologic test that did not exceed 1 cm from the applicator surface .
the single dose of 20 gy was delivered to the treatment volume with 1 cm margins ( figs . 2 and 3 ) . in case of insufficient hemodynamic parameters such as high amount of blood loss ,
the abdominal cavity was closed , but packing ( cotton cloth ) was placed on location were organ removal occurred and triggered ambiguous homeostasis .
, the additional postoperative ebrt radiation after iobrt was applied meanly after 30 days from combined retroperitoneal sarcomas / iobrt surgery .
ebrt planned dose of site and postoperative scar was 50 gy in 1.8 gy fractions .
a ) 3d image of ham applicator position , b ) dose distribution and ham applicators location the clinical and pathological parameters examined for prognostic value within the group undergoing iobrt were tumor size ( divided into two groups : < 10 and > 10 cm ) , histological malignancy grade of tumor ( low grade g1 vs. high grade g2 or g3 ) , histological tumor type ( liposarcoma vs. others ) , sex , one - time resection with a contiguous organ ( zero additional organs , one organ , and more than one organ ) , number of previous operations ( zero , one , or more than one ) , and subsequent ebrt . we did not include the microscopic status of resection margins r0 vs. r1 in this analysis , because the probability of reliable estimation found mostly in recurrent retroperitoneal sarcomas is doubtful .
postoperative follow - up consisted of physical examination and routine imaging investigations such as computed tomography and ultrasonography of the abdominal cavity as well as chest x - ray / x - rays .
observations were assessed and analyzed every 3 months for the first 2 years , then in the 3 to 5 year period every 6 months , and annually thereafter .
the median follow - up time was 40 months for survivors ( range : 8 - 100 months ) and for iobrt patients 39 months ( range : 8 - 82 months ) .
overall survival ( os ) time was calculated from the date of operation at the study institution to the date of the most recent follow- up or death . the local recurrence free survival ( lrfs )
time was estimated from the date of retroperitoneal sarcoma excision to the date of the most recent follow up or local retroperitoneal sarcomas recurrence . for prospective data collection ,
statistical analysis was performed using statistica software ( statsoft , tulsa , ok ) . in univariate analysis survival rate
was assessed using the kaplan - meier method in combination with the log - rank test .
multivariate analysis for overall survival was performed with the use of proportional hazard cox regression model .
74 ( 85% ) patients qualified for retroperitoneal surgery of sarcoma underwent radically macroscopic surgery .
the estimated 5-year os for the entire group of retroperitoneal sarcomas patients after radical macroscopic resection was 41% ( median survival time : 48 months ) , and the evaluated 5-years lrfs was 61% . in the total group of patients with retroperitoneal sarcoma
it was necessary to remove another organ along with the tumor in 79% of patients ( 60/74 cases with r0/r1 resection ) - one organ in 20 patients and more than 1 organs in 40 patients . within the iobrt group
, there was a total of 75% of patients ( 43 cases ) were removal was performed
one organ in 11 patients ( 19.2% ) and more then 1 organ in 32 patients ( 56.1% ) .
the most often removed organ was as follows : kidney ( 39 cases ) , large intestine ( 28 cases ) , small intestine ( 10 cases ) , ovary ( 8 cases ) , spleen ( 7 cases ) and iliopsoas ( 6 cases ) .
57 patients ( 67.8% ) were ultimately qualified for brt , out of which 48 patients ( 84% ) underwent one - time brt at the time of surgery , directly after removal of retroperitoneal sarcoma , whereas 9 patients ( 16% ) underwent iobrt in 1 - 3 days after retroperitoneal sarcoma removal due to poor parameters at the time of surgery . for reasons of high amount of blood loss and/or hemodynamical disorders , the patients were not able to receive one - time brt on the day of surgery .
only 4 patients ( 14.8% ) had primary sarcomas that were diagnosed at the dstbs , while the remaining 85.2% cases were qualified for treatment as recurrences after previously completed surgery and ebrt outside our clinic .
the reasons for iobrt disqualification were as follows : multifocal changes undetected during preoperative imagining evaluations : 11 patients , non - radical resection : 5 patients , tumor localized on large vessels : 4 patients , circulatory failure and high amount of blood loss during surgery : 3 patients , liver metastases confirmed intraoperatively 2 patients , irradiation before co - i : 2 patients .
the final resection margins were evaluated as radically microscopic ( r0 ) in 37 cases ( 65% ) , while tumor infiltration in microscopic investigation of resection margins ( r1 ) was confirmed in 20 cases ( 35% ) .
clinical characteristics of 57 retroperitoneal sarcoma patients treated with intraoperative brachytherapy different number of applicators was used because of the diameter of the field ( ranged from 4 to 19 ) .
the total irradiation time ranged from 20 to 87 minutes with mean value of 56 min . in two patients it was necessary to install two ham applicators due to large radiation fields requiring two applicators with 10 adapters ( 6 and 9 adaptors were used ) in asymmetrical position . during 30 days after surgery one patient died ( 1.2% ) .
surgery was necessary in 10 patients ( 17.5% ) due to postoperative complications after iobrt which included intraperitoneal abscess ( 2 cases ) , fecal fistula ( 2 cases ) , wound dehiscence ( 2 cases ) , adhesive mechanical ileus ( 1 case ) , duodenal fistula ( 1 case ) , hemorrhage ( 1 case ) , and massive hydroperitonia ( 1 case ) .
the complications appeared only in patients operated due to recurrences of retroperitoneal sarcoma . in the group of patients after adjuvant ebrt ( 34 cases ) , the most common late complication was symptoms of chronic , recurrent mechanical sub - ileus of intestine ( 6/34 patients : 17.6% ) .
two patients in late postoperative periods underwent surgery due to mechanical ileus symptoms ( in one case with accompanying intestinal fistula : the patient died because of complications ) , in 15 and 26 months after the primary brt and surgery . in a distant period of time ,
the estimated 5 year overall survival ( os ) in group of 57 patients after iobrt was 50% ( mean value : 58 months ) ( fig .
at the end of follow - up , 30 patients were alive ( 53% ) , 18 ( 32% ) died due to progression of the disease , while 8 patients ( 14% ) died from reasons not associated with sarcoma progression ( 5 cases all medical reasons , mainly circulatory system ; 3 cases - treatment complications ) .
overall survival ( os ) of patients with retroperitoneal sarcomas in iobrt group in univariate analysis the important factors negatively influenced the os of patients with retroperitoneal sarcoma under iobrt were as follows : sarcoma recurrence surgery ( p = 0.002 ) ( fig .
5 ) , higher grade of sarcoma histological malignancy ( p = 0.005 ) ( fig .
6 ) , histological type different than liposarcoma ( p = 0.05 ) and lack of adjuvant therapy of ebrt ( p = 0.05 ) ( table 2 ) . in multivariate analysis ,
the independent factors of os were : sarcoma recurrence surgery ( p = 0.02 ) and histological type different than liposarcoma ( p = 0.04 ) ( table 3 ) .
the actual 3-year overall survival rate was 82% for patients operated due to primary retroperitoneal sarcoma and 50% for patients operated due to recurrence of retroperitoneal sarcoma , previously operated in another clinic ; os reached 76% in retroperitoneal sarcoma group of patient with g1 histological grade of malignancy , compared with 48 % for g2/g3 tumors ; 71% for liposarcoma patients , compared with 37% for other histological sarcomas ; 70% for additional postoperative radiotherapy patient , compared with 43,5% of patients without additional ebrt .
no substantial differences in overall survival rate was noticed regarding the size of operated tumor , sex and the number of removed adjoining organs ( table 2 ) .
the estimated 5-year local recurrence free survival ( lrfs ) in 57 patients after iobrt was 65% ( fig .
prognostic factors influencing overall survival ( os ) and local recurrence free survival ( lrfs ) after brachytherapy ( brt ) univariate analysis n.s .
statistically no significant independent prognostic factors for overall survival rates in retroperitoneal sarcomas , treated with intraoperative brachytherapy
multivariate analysis statistically important overall survival ( os ) of retroperitoneal sarcoma patients in iobrt group according to prime tumor surgery ( p ) or recurrence surgery ( w ) overall survival ( os ) of retroperitoneal sarcomas patients treated with iobrt according to histological grade of sarcoma malignancy overall local recurrence free survival in retroperitoneal sarcoma patients treated with iobrt on the basis of univariate analysis , the significant factors negatively inclined lrfs of retroperitoneal sarcoma patients after iobrt were : sarcoma recurrence surgery ( p = 0.008 ) and lack of ebrt ( p = 0.01 ) ( fig . 8) .
overall local recurrence free survival in patients with retroperitoneal sarcoma treated with iobrt according to adjuvant postoperative ebrt the actuarial 3-year lrfs was 100% for patients operated due to primary retroperitoneal sarcoma and only 66% for patients operated due to recurrence of retroperitoneal sarcoma that were previously operated in different clinic .
lrfs reached 87% in patients with postoperative radiotherapy compared with 57% of patients without additional radiotherapy .
no significant differences were estimated in lrfs regarding the size of operated tumor , sarcoma malignancy grade , histological type , sex and the number of removed adjacent organs ( table 2 ) .
24 cases ( 42% ) of recurrences were noticed : liver recurrences ( n = 3 ; 12.5% ) , lung recurrences ( n = 3 ; 12.5% ) , bone recurrence ( n = 1 ; 4% ) mainly local and intraperitoneal recurrences . since 2000 , a total number of 34 patients qualified for treatment ( 60% of all ) and additional ebrt was performed ( usually in 30 days after the main combined iobrt / surgery ; in most of the cases the time gap was larger due to wound - healing process and radiation planning procedure ) .
some patients were disqualified from postoperative radiotherapy due to following reasons : previous radiotherapy given in another clinic , bad general condition , intestine fistula , disease progression .
all patients , with the exception of 3 ( one case of no - tumor related neurological disorders , one case of radiation induced enteronitis and one patient s resignation from further participation in the study after reception of 36 gy dose ) received presumed dose of 50 gy .
the final resection margins were evaluated as radically microscopic ( r0 ) in 37 cases ( 65% ) , while tumor infiltration in microscopic investigation of resection margins ( r1 ) was confirmed in 20 cases ( 35% ) .
clinical characteristics of 57 retroperitoneal sarcoma patients treated with intraoperative brachytherapy different number of applicators was used because of the diameter of the field ( ranged from 4 to 19 ) .
the total irradiation time ranged from 20 to 87 minutes with mean value of 56 min . in two patients it was necessary to install two ham applicators due to large radiation fields requiring two applicators with 10 adapters ( 6 and 9 adaptors were used ) in asymmetrical position . during 30 days after surgery one patient died ( 1.2% ) .
surgery was necessary in 10 patients ( 17.5% ) due to postoperative complications after iobrt which included intraperitoneal abscess ( 2 cases ) , fecal fistula ( 2 cases ) , wound dehiscence ( 2 cases ) , adhesive mechanical ileus ( 1 case ) , duodenal fistula ( 1 case ) , hemorrhage ( 1 case ) , and massive hydroperitonia ( 1 case ) .
the complications appeared only in patients operated due to recurrences of retroperitoneal sarcoma . in the group of patients after adjuvant ebrt ( 34 cases ) , the most common late complication was symptoms of chronic , recurrent mechanical sub - ileus of intestine ( 6/34 patients : 17.6% ) .
two patients in late postoperative periods underwent surgery due to mechanical ileus symptoms ( in one case with accompanying intestinal fistula : the patient died because of complications ) , in 15 and 26 months after the primary brt and surgery . in a distant period of time ,
the estimated 5 year overall survival ( os ) in group of 57 patients after iobrt was 50% ( mean value : 58 months ) ( fig .
at the end of follow - up , 30 patients were alive ( 53% ) , 18 ( 32% ) died due to progression of the disease , while 8 patients ( 14% ) died from reasons not associated with sarcoma progression ( 5 cases all medical reasons , mainly circulatory system ; 3 cases - treatment complications ) .
overall survival ( os ) of patients with retroperitoneal sarcomas in iobrt group in univariate analysis the important factors negatively influenced the os of patients with retroperitoneal sarcoma under iobrt were as follows : sarcoma recurrence surgery ( p = 0.002 ) ( fig .
5 ) , higher grade of sarcoma histological malignancy ( p = 0.005 ) ( fig .
6 ) , histological type different than liposarcoma ( p = 0.05 ) and lack of adjuvant therapy of ebrt ( p = 0.05 ) ( table 2 ) . in multivariate analysis ,
the independent factors of os were : sarcoma recurrence surgery ( p = 0.02 ) and histological type different than liposarcoma ( p = 0.04 ) ( table 3 ) .
the actual 3-year overall survival rate was 82% for patients operated due to primary retroperitoneal sarcoma and 50% for patients operated due to recurrence of retroperitoneal sarcoma , previously operated in another clinic ; os reached 76% in retroperitoneal sarcoma group of patient with g1 histological grade of malignancy , compared with 48 % for g2/g3 tumors ; 71% for liposarcoma patients , compared with 37% for other histological sarcomas ; 70% for additional postoperative radiotherapy patient , compared with 43,5% of patients without additional ebrt .
no substantial differences in overall survival rate was noticed regarding the size of operated tumor , sex and the number of removed adjoining organs ( table 2 ) .
the estimated 5-year local recurrence free survival ( lrfs ) in 57 patients after iobrt was 65% ( fig .
prognostic factors influencing overall survival ( os ) and local recurrence free survival ( lrfs ) after brachytherapy ( brt ) univariate analysis n.s .
statistically no significant independent prognostic factors for overall survival rates in retroperitoneal sarcomas , treated with intraoperative brachytherapy
multivariate analysis statistically important overall survival ( os ) of retroperitoneal sarcoma patients in iobrt group according to prime tumor surgery ( p ) or recurrence surgery ( w ) overall survival ( os ) of retroperitoneal sarcomas patients treated with iobrt according to histological grade of sarcoma malignancy overall local recurrence free survival in retroperitoneal sarcoma patients treated with iobrt on the basis of univariate analysis ,
the significant factors negatively inclined lrfs of retroperitoneal sarcoma patients after iobrt were : sarcoma recurrence surgery ( p = 0.008 ) and lack of ebrt ( p = 0.01 ) ( fig .
overall local recurrence free survival in patients with retroperitoneal sarcoma treated with iobrt according to adjuvant postoperative ebrt the actuarial 3-year lrfs was 100% for patients operated due to primary retroperitoneal sarcoma and only 66% for patients operated due to recurrence of retroperitoneal sarcoma that were previously operated in different clinic .
lrfs reached 87% in patients with postoperative radiotherapy compared with 57% of patients without additional radiotherapy .
no significant differences were estimated in lrfs regarding the size of operated tumor , sarcoma malignancy grade , histological type , sex and the number of removed adjacent organs ( table 2 ) .
24 cases ( 42% ) of recurrences were noticed : liver recurrences ( n = 3 ; 12.5% ) , lung recurrences ( n = 3 ; 12.5% ) , bone recurrence ( n = 1 ; 4% ) mainly local and intraperitoneal recurrences . since 2000 , a total number of 34 patients qualified for treatment ( 60% of all ) and additional ebrt was performed ( usually in 30 days after the main combined iobrt / surgery ; in most of the cases the time gap was larger due to wound - healing process and radiation planning procedure ) .
some patients were disqualified from postoperative radiotherapy due to following reasons : previous radiotherapy given in another clinic , bad general condition , intestine fistula , disease progression .
all patients , with the exception of 3 ( one case of no - tumor related neurological disorders , one case of radiation induced enteronitis and one patient s resignation from further participation in the study after reception of 36 gy dose ) received presumed dose of 50 gy .
however , series of publications were released with multiple sets of data regarding the treatment results of patients with this type of cancer . [ 18 , 2332 ] .
it seem like the best option for the longest distant survival rate is a radical resection during the primary surgery of retroperitoneal sarcoma [ 6 , 18 , 32 , 33 ] . however , such surgery is not always possible due to large size of the tumor and deep infiltration of adjoining organs .
such observation is confirmed by results of this study in which over 70% of recurrences can be qualified as local recurrences .
this is to imply that the upgrading of local treatment can be transmitted into a better cure rate .
furthermore , strong scientific evidence confirms that additional ebrt improves local control with association of surgery in trunk or extremities sarcoma locations , with absence of microscopically radical margins [ 19 , 34 ] .
similar publications regarding combined treatment ( surgery and ebrt ) in retroperitoneal sarcoma demonstrate decrease of local recurrences rate [ 14 , 35 , 36 ] .
series of studies where ebrt was used in adult soft tissue sarcoma patients show precise correlation with percentage of local recurrence and radiation dose [ 34 , 37 ] .
the effective therapeutic dose ( above 60 gy ) is not possible to be acquired in case of retroperitoneal sarcoma due to tumor proximity with organs at risk such as intestines , parenchyma organs and large vessels in potential radiation field .
intraoperative radiation with the use of electron accelerator or hdr brt ( used in our clinic ) is the alternative way of treatment to ebrt in case of soft tissue sarcoma with high malignancy level [ 26 , 38 , 39 ] .
brachytherapy allows high radiation dose application on site of removed sarcoma ( place of high risk of local recurrence ) and at the same time secures from unnecessary irradiation of critical organs that could be found in the radiation field [ 22 , 26 , 35 , 39 ] .
theoretical advantage of brachytherapy is a direct visualization of a treated field that allows better control of irradiated area and the usage of higher radiation dose .
biological effectiveness of such sole dose results in 2 to 5 times better efficiency than in case of dose fractionation in traditional way ( directly into site of removed sarcoma ) .
such way of radiation allows effective saving of surrounding tissues in comparison with preoperative or postoperative radiotherapy .
iobrt can be combined with ebrt and therefore making it possible to increase the total radiation dose to more than 65 gy .
in our study , one of the largest in the world , 68% of patients operated for retroperitoneal sarcoma received iobrt .
it is difficult to establish the complications of radiotherapy due to series of complexities connected to extensive and prolonged surgical treatment or towel pressure ( ischemia ) , isolating critical organs from intraoperative field irradiation . frequently , the surgical procedures were very extensive , demanding removal of adjoining organs along with sarcoma ( 80% of cases ) .
this is to imply that such type of procedure should be performed in specialized and experienced centres by qualified anesthesiologists , radiotherapists and oncologists surgeons .
the reports regarding benefits of brt application in soft tissues sarcoma treatment are still ambiguous [ 34 , 35 ] .
they show the tendency to improve local control with the use of intraoperative radiotherapy [ 22 , 36 ] .
somewhat different matter of substance constitutes brt combined with ebrt . in case of sarcomas with extracompartmental localization such as retroperitoneal sarcomas and local recurrences
, it might be essential to apply larger spectrum of radiation like brt combined with ebrt .
ebrt can be used as an addition to pre- or post- operative treatment [ 15 , 16 , 21 , 22 , 36 , 4144 ] . in the original study protocol presented within this work ,
furthermore , obtained results of such additional therapy application appear to be necessary in combined treatment of retroperitoneal sarcomas . within the group of postoperative additional ebrt patients , local control of tumor and better ( 70% ) overall survival rate
the combination of these two radiotherapy techniques permits to achieve appropriate large total therapeutic dose .
theoretically , such type of treatment could bring certain benefits in consideration of common delays or disqualification for postoperative ebrt due to concurrent complications in extensive surgeries , as well as improved definition of radiation field with the use of preoperative radiotherapy [ 45 , 46 ] .
other methods of treatment including systematic chemotherapy ( except microcellular sarcomas of ewing s sarcomas ) or intraperitoneal therapy do not present significant influence in treatment improvement . overall survival rate or local recurrence survival of the studied group of patients are comparable with other international results of analyzed group of retroperitoneal sarcomas patients . however , the majority of literature information are formulated on the basis of small group of patients with divergent data ( 5 year survival rate oscillating between 12% to 70% ) [ 6 , 15 , 18 , 23 , 25 , 32 , 33 , 4759 ] .
moreover , it is difficult to find present day data of patients treated with surgery as a sole way of treatment .
the analysis published by royal marsden hospital in london revealed that 20% of 5-year survival , whereas in our study 5-year survival in brachytherapy patients is 50% .
what is also significant , other polish results of surgically treated retroperitoneal sarcomas patients with no extensive , multi - organ en - bloc resection and iobrt / surgery , showed only 34% of 5-year overall survival and 23% of 5-year of asymptomatic survival .
storm and mahvi demonstrated 72% of 5-year local recurrence free survival in group of 204 of retroperitoneal sarcomas patients after macroscopic radical surgical treatment .
this study correlates findings of our group of patients as 65% of 5-year local recurrence free survival after intensive surgical treatment combined with iobrt .
surgical procedure allowing en - bloc sarcoma removal along with at least one of adjoining organs in order to obtain large margin of resection , enables significant improvement of retroperitoneal sarcomas treatment results [ 53 , 55 ] .
apart from histological malignancy level , the quality of surgical treatment represents the most significant factor to influence the results of retroperitoneal sarcomas treatment .
recently published analyses of french and italian scientists confirm this observations [ 55 , 6164 ] .
the group of patients in our study mostly consisted of patients with high histological malignancy level of sarcomas .
the histological malignancy level is the most important prognosis factor for overall survival in soft tissue sarcoma patients as well as in retroperitoneal sarcomas patients [ 53 , 57 , 59 , 65 ] confirmed by above data .
majority of patients were operated not because of primary sarcoma , but due to local recurrence after ineffective treatment beyond our centre .
unfortunately , treatment of local recurrence is associated ( in significant percentage of cases ) with consecutive local recurrence .
in group of patients presented in international literature , the predominated group consisted of patients operated primarily not due to recurrence [ 32 , 54 , 5658 ] . in our study
we confirmed that treatment of primary retroperitoneal sarcomas is one of the major factor influencing prognosis ( on the basis of multivariate analysis with its limitation resulting from numerical amount of cases in analyzed group ) .
the results of our study present that in order to achieve such good treatment results , despite significantly substantial amount of patients operated due to recurrence of retroperitoneal sarcoma , is associated with the application of iobrt followed by postoperative ebrt . under ideal circumstances , patients with primary retroperitoneal sarcoma should be instantly directed for combined treatment .
it is important to emphasize that the appropriate planning of the treatment procedure and realization of planed therapeutic protocol in centers with adequate experience in this field is the major factor that influence the improvement of results of overall survival and local recurrence free survival in patients with retroperitoneal sarcoma .
the case study formulation of combined treatment of retroperitoneal sarcoma patients was evaluated on the basis of one centre group of sarcoma patients qualified for combined treatment ( surgery + iobrt ) and it was possible to conduct in 68% of patients .
presented results : 50% of 5-year os and 65% of 5-year lfrs are comparable with the results of major international oncologic centers
. the outcomes account for the necessity of further investigations in order to improve the effects of combined retroperitoneal sarcoma treatment .
the amount of complications in our study is quite high , however acceptable , taking into consideration very extensive , multi - organ surgical procedures with frequent cases of local recurrences . presented analysis show that the improvement of treatment results in retroperitoneal sarcoma patients is genuinely achievable in case of primal treatment performed in high- specialist oncologic centre with possible application of brachytherapy and radiotherapy as well as experience and appropriate knowledge in treatment of retroperitoneal sarcoma patients . | purposethe primary aim of this work was to analyze feasibility of combined treatment of retroperitoneal sarcomas ( rs ) : surgery ( s ) and intraoperative brachytherapy ( iobrt ) .
the secondary aim was to analyze results and complications after this treatment.material and methods84 patients with retroperitoneal sarcomas were qualified for combined treatment ( s and iobrt ) between june 1998 and september 2006 .
65 of the patients ( 77.4% ) had local recurrences .
sarcomas with intermediate and high grade of histological malignancy ( g2 , g3
76.2% ) were the most frequent within the all surgically treated patients .
resection ability ( r0/r1 ) in analyzed group of patients was estimated as 85% ( 74 cases ) .
after intraoperative evaluation , 57 ( 67.8% ) patients were qualified for iobrt . since 2000 , in 34 patients ( 60% ) an adjuvant postoperative external beam radiation therapy ( ebrt ) in dose of 50 gy was applied .
median follow - up of the surviving patients was 40 months.resultson the basis of the univariate analysis , relevant aspects negatively influencing overall survival rate within the rs group treated with iobrt were as follows : surgery of sarcoma recurrence ( p = 0.002 ) , higher grade of histological malignancy ( p = 0.05 ) , histological type different than liposarcoma ( p = 0.05 ) as well as no adjuvant ebrt ( p = 0.05 ) .
on the basis of multivariate analysis one can ascertain that relevant factors negatively influencing lrfs in rs patients treated with iobrt were : surgery due to recurrence of sarcoma ( p = 0.008 ) and lack of ebrt ( p = 0.01).conclusionscombined treatment ( surgery and brachytherapy ) was possible to be carried out on 68% of rs patients .
the overall number of complications was quite high , however acceptable , taking into consideration the application of extensive , multi - organ treatments in case of sarcoma recurrences in this localization .
the results suggest that the method of treatment will improve the final outcome when most of patients will be qualified for treatment of primary sarcomas in experienced centre . |
femoral intertrochanteric fractures in elderly patients often result in serious complications if proper and timely treatment is not provided . in particular
, the major objective of surgical treatment in the elderly might be the recovery of ambulatory ability in conjunction with fixation of fractures .
it is however important to note that treatment of young patients for intertrochanteric fractures should not be limited to ambulation recovery but should also consider resumption of sport activities .
intertrochanteric fractures are often treated by surgical approaches that use compression hip screws , intramedullary nails , or hip arthroplasty1 ) .
one of them is that compression hip screws provide compression pressure force on the surface of the fractures , thereby enhancing bone union . in the case of unstable fractures , however , excessive compression force may result in femoral shortening , which would be a significant drawback2 ) .
proximal femoral shortening causes shortening of the abductor lever arm and results in leg length discrepancy ( lld ) .
these drawbacks increase physical stress on the hip when walking , which may result in pain and development of osteoarthritis , particularly in non - elderly patients who are required to be socially active3 ) .
the compression force may occur at two different points in procedures that involve the use of compression hip screws .
the other possibility is when physical stress is applied to patient 's hip through their body weight , that is weight bearing .
so far , most studies have discussed compression without considering the timing34 ) . in addition , most results in previous studies were not adjusted ; hence , patient 's body weight and size were not considered .
the major objective of the present study was to investigate proximal femoral shortening after surgical treatment of femoral intertrochanteric fractures using compression hip screws in patients who were under the age of 60 years and had no history of diseases requiring regular treatment .
from march 2005 through february 2014 , patients who underwent femoral intertrochanteric fracture surgery using compression hip screws were enrolled in the study .
inclusion criteria were as follows : 1 ) patients who had no history of diseases requiring treatment on a regular basis and 2 ) patients were younger than 60 years .
exclusion criteria were as follows : 1 ) fracture non - union was observed , 2 ) patients had previous damage of both femora when the fracture occurred , 3 ) no radiological data was available before and after surgical procedures and for the follow - up period , 4 ) radiological data was not able to be measured , and 5 ) patients had pathological fractures .
all procedures were performed by a single surgeon , while data analysis was done by the same surgeon and another doctor ( fellowship ) .
a total of 185 patients under the age of 60 years underwent surgical treatment , of which 37 patients ( 23 males and 14 females ) were included in this study based on our inclusion and exclusion criteria .
the average age of the patients was 47 years ( range , 26 - 60 years ) .
the average follow - up period after surgery was 23 months ( table 1 ) . in this study , we assumed that the following four major factors may significantly influence femoral shortening : the aspect of the fracture , a defect of the postero - medial wall , a defect of the lateral wall , and the degree of reduction . using these factors , we categorized the patients into subgroups and then the impact of each factor was estimated by quantifying the degree of proximal femoral shortening it caused .
proximal femoral shortening was expressed as femoral offset and lld , which represent the changes of horizontal and vertical vectors , respectively .
the changes were measured at two different time points when compression was occurring : right after surgery and after bone union ; the total value was then subtracted by the femoral shortening value measured right after surgery to calculate the shortening ratio caused by dynamic compression .
a fracture was defined as 31 a1 if a single fracture line was extending to the medial cortex by intertrochanteric fractures and as a2 if more than one such fracture line was present .
nine , 18 , and 10 patients were found to have 31 a1 , 31 a2 , and 31 a3 fractures , respectively ( table 2 ) .
fractures were further classified according to syntripsis of the lateral wall of the proximal femur from the tip of the greater trochanter through the lesser trochanter site .
the defect of the postero - medial wall was defined as more than two - thirds of the lesser trochanter being isolated from the medial intertrochanteric region in the post - operative anteroposterior ( ap ) view of the pelvis .
two different tools were used : 1 ) 135 compression hip screws ( chs system ; solco , pyeongtaek , korea ) and 2 ) 129anti - hypersliding compression hip screws developed in our hospital ( break top system compression hip screw ; solco ) .
in addition to these basic compression hip screws , greater trochanter - stabilizing plates were used for unstable fractures ; fracture stability was estimated in advance to or in the middle of surgery when the general condition of the patient allowed .
if their condition allowed , all patients were advised to sit on their bed upright as well as in a wheelchair right after surgery .
radiographs were taken on the next day after surgery and then the patients were assessed for their ambulation level , pain , and activity level 2 weeks , 3 months , 6 months , and 1 year after surgery , respectively , radiographs were taken at the same time points .
the modified harris hip score ( hhs ) was used after bone union to assess the recovery of patients ' function .
pelvis ap and hip axial view radiographs were taken whilst the tip - apex distance ( tad ) , degree of reduction , location of lag screws , and proximal femoral shortening were assessed using post - operative radiographs .
the reduction of fractures was determined as non - anatomical reduction if more than one site had a 3-mm or larger step - off of the cortex in post - operative ap or axial view radiographs .
shortening of the proximal femur was measured from changes in femoral offset and leg length .
in the ap view of the pelvis obtained using the picture archiving and communication system ( pacs ) , shortening of the femoral offset was measured as a surrogate marker given its similarity with the length of the abductor lever arm5 ) . to measure the femoral offset ,
a circle close to the femoral head was drawn on the ap radiograph of the pelvis using the pacs in order to make the head center , and then a line dividing the stem part that is 10 cm apart from the lowest part of the lesser trochanter was drawn ; the horizontal distance between the line and the head center was measured ( fig .
when measured , the diameter of the lag screw shaft was assessed to correct measuring errors potentially due to differences in magnification , and then the measured value was corrected again based on the obtained ratio compared to the actual diameter , 8.4 mm . to estimate the lld ,
the tear drop was established based on patient 's pelvis and then the tip of either the greater or lesser trochanter ( whichever of them did not show any changes during bone union ) was selected as a femoral reference to measure the difference between the normal and damaged sites . to minimize error due to rotation in measurements using ap views of the pelvis , radiographs showing the same size of lesser trochanters
were selected ; in serial follow - up analyses , only radiographs showing similar sizes of lesser trochanters were chosen for further analyses .
measurements were performed right after surgery and after bone union , i.e. the two time points at which compression was occurring , as mentioned above .
in addition , percentage was calculated by dividing the corrected value per body size by femoral offset on the normal side .
nonparametric analyses , mann - whitney test , and kruskal - wallis test were used to examine the differences in the four major factors ( the aspect of the fracture , a defect of the postero - medial wall , a defect of the lateral wall , and the degree of reduction ) using the ibm spss statistics software ver . 19.0 ( ibm co. , armonk , ny , usa ) . a p - value
the tad was within 25 mm in 30 patients and 25 - 28 mm in 7 patients .
all 37 patients were satisfied with the location of lag screws ( center - center on the pelvis ap and hip axial view radiographs ) .
shortening that occurred during surgery was subtracted from this value to obtain shortening that solely resulted from dynamic compression because of weight loading ; it was found to be 3.48 mm .
shortening of the femoral offset was 5.45 mm after bone union , whereas corrected shortening ( i.e. , shortening that was caused solely by weight loading ) was 3.56 mm .
the average shortening caused by dynamic compression divided by the femoral offset on the normal side was found to be 8.32% .
overall , in a total of 37 patients , 65.32% of femoral offset shortening and 39.36% of lld were caused by dynamic compression .
a significant femoral offset reduction was found in the group that had non - anatomical reduction , a defect of the postero - medial wall compared to the group with anatomical reduction and the group with no defect on postero - medial wall ( p=0.002 ; table 3 ) .
both the decrease in femoral offset by weight loading and the percentage corrected for individual body size were statistically significant .
in contrast , neither the aspect of the fracture nor the defect of the lateral wall was significantly associated with femoral shortening ( p=0.552 and 0.237 , respectively ) .
regarding femoral offset reduction and the percentage corrected for body size , high - risk and low - risk groups were defined on the basis of the reference value of 10% .
the high - risk group included 16 patients . in the functional test using the modified hhs , the low - risk group had an average value of 85.47 points , which was slightly higher than the group with a high risk of shortening ( 83.13 ) , yet the difference did not reach statistical significance ( p=0.091 ) .
logistic regression analysis showed that none of the risk factors was statistically significant in the group with a high risk of femoral offset shortening ; however , the p - values for three risk factors ( except for the fracture aspect ) were on the borderline of statistical significance ( table 4 , 5 ) .
none of the risk factors were significant for lld . in the group with anatomical reduction ,
the average value of lld caused by dynamic compression was 3.07 mm , whereas in the group with non - anatomical reduction it was 4.08 mm .
the lld values of the group with a defect of the postero - medial wall and the one without a defect were 3.72 mm and 3.34 mm , respectively .
the compression hip screw is a tool that uses the concept of a tension band plate6 ) .
consequently , the defects on the medial wall may lead to significant clinical outcomes after surgery . in this study , we found that 15 patients had defects on the postero - medial wall .
we also found a significant femoral offset reduction in the groups with non - anatomical reduction and a posteromedial wall defect .
these results indicate that the fixation force of a compression hip screw weakens in the absence of proper support when weight bearing is resumed .
neither the aspect of the fracture nor syntripsis of the lateral wall was shown to be significant for proximal femoral shortening . regarding the aspect of the fracture , a trochanteric stabilizing plate ( tsp )
was employed in patients with ao / ota 31 a2 and 31 a3 fractures , which may confer additional stability and explain the absence of significant association between the aspect of the fracture and proximal femoral shortening .
similarly , we believe that no association was observed between the defect of the lateral wall ( syntripsis ) and proximal femoral shortening because of the additional stability provided by the tsp7 ) . it has been demonstrated that proximal femoral shortening is affected by multiple factors after surgical treatment for femoral intertrochanteric fractures . in particular ,
the degree of tad and the fracture aspect have been suggested to be significant risk factors8 ) . in the present study ,
7 patients had tad exceeding 25 mm ; among them , 6 were further categorized into the high - risk group ( > 10% of femoral offset shortening ) . when bone density was categorized by using the singh index , all patients except 5 had the index values higher than 4 .
this might be because our study included patients under the age of 60 , which limited the comparison between groups with different bone density .
another limitation of our study was that the femoral offset was measured using two - dimensional ( 2d ) ap views of the pelvis .
in other studies , changes in the abductor lever arm were analyzed using either cad or pacs9 ) , both of which can accurately measure when no change of greater trochanteric shape is shown .
however , changes in the shape of the greater trochanter during bone union are very often found in patients with syntripsis . in this , the use of cad may result in errors , beause their shape ( i.e. , that of the greater trochanter ) is not identical to the one on the normal side . similarly , when x - rays are used , the image of the outer slope of the greater trochanter is modified ; thus , considerable measuring error might be expected in drawing vertical lines . to overcome such limitations ,
we measured femoral offset shortening on pelvis ap view radiographs using the pacs instead of measuring the length of the abductor lever arm . in addition , it was suggested that 3d measurements could be more accurate than 2d measurements10 ) . in 2d measurements ,
importantly , we noted that considerable numbers of post - operative radiographs showed femoral rotation .
these results indicate that , for reduction , the fixation was done in which internal rotation was excessive . in the present study , these patients were excluded as significant error was expected in measurements .
lastly , we aimed to achieve consistent femoral rotation by comparing the sizes of the lesser trochanter and greater trochanter in serial pelvis ap radiographs of the same patient .
in surgical procedures for femoral intertrochanteric fractures , one should consider post - operative activities , especially for non - elderly patients .
although compression hip screws may enhance bone union through compression force , excessive force often results in proximal femoral shortening , thereby hindering patients ' normal physical activities and functions .
theoretically speaking , stable fixation using compression hip screws is contingent to the stability of the femoral postero - medial wall .
as expected , in the present study , we were able to confirm a significant association between the stability of the proximal femoral postero - medial wall and the reduction in femoral offset .
hence , we recommend that surgeons 1 ) secure the reconstruction of damaged postero - medial wall and 2 ) perform anatomical reduction in intertrochanteric surgeries using compression hip screws . | purposewe aimed to quantify proximal femoral shortening after operation with compression hip screws for intertrochanteric fracture in patients under the age of 60 years.materials and methodswe followed 37 consecutive patients with intertrochanteric fractures treated with compression hip screws from march 2005 to february 2014 .
we designated the aspect of the fracture , a defect of the postero - medial wall , a defect of the lateral wall , and the degree of reduction as four potentially important factors we assumed would strongly affect proximal femoral shortening .
we quantified proximal femoral shortening and compared the effects of above factors .
we divided femoral shortening into two plane vectors ; femoral offset in the horizontal plane and leg length discrepancy in the vertical plane .
we measured shortening separately during two periods : during operation and after weight bearing ( called dynamic compression).resultsafter bone union , the average femoral offset shortening was 5.45 mm .
patient groups with anatomic reduction and intact postero - medial wall showed lower femoral offset shortening than the respective opposite groups .
as to functional score using modified harris hip score , low femoral offset shortening group showed more 2.35 scores than high groups .
none of the factors significantly affected leg length shortening.conclusionwe found that a stable medial buttress is involved in lower femoral offset shortening .
thus , surgeons need to attempt to recover the defect of the medial wall and to reduce anatomically when operating intertrochanteric fractures with compression hip screws . |
participants ( n = 3,234 ) at high risk for developing type 2 diabetes were randomized to the dpp between 1996 and 1999
. characteristics of the study population are reported elsewhere ( 1 ) . in july 2001 , masked dpp treatment was discontinued after it was established that lifestyle intervention reduced incidence of diabetes by 58% and metformin by 31% compared with placebo ( 2 ) .
all 3,150 surviving dpp participants who had not withdrawn consent were eligible for the dppos , and 2,665 enrolled .
participants signed written consent forms after discussion of all aspects of the studies with study staff ( 3 ) .
dpp / dppos participants brought all prescription medicines , including adms , to clinic visits .
diabetes was diagnosed based on an annual oral glucose tolerance test or a semiannual fasting plasma glucose test .
fasting insulin was measured at annual visits with the oral glucose tolerance test ( 2 ) .
adm use was reported quarterly during the dpp and every 6 months during the dppos .
cox proportional hazard models ( 1 ) were used to evaluate whether taking adms was associated with developing diabetes .
adm use was defined as a time - dependent categorical variable up to each time point evaluated with three levels : never used , used intermittently ( at least once but not always ) , and used continuously ( at all visits ) . at each successive time point , the value of the variable was calculated based on all previous time points , including the current measurement . a significant interaction between adm use and treatment groups
time - dependent covariate analyses ( 1 ) were used to model the above covariates and diabetes risk with adjustment for factors associated with an increased risk of developing diabetes ( race / ethnicity , age , sex , education , fasting plasma glucose at baseline , weight at baseline , and weight change during the study ) .
we now present data over a median of 10 years since randomization , including the time period of the first phase of the dpp that was reported previously ( 1 ) .
therefore , these analyses are not independent of the previous study and should be considered an extension , not a replication , of those findings .
adm use was reported quarterly during the dpp and every 6 months during the dppos .
cox proportional hazard models ( 1 ) were used to evaluate whether taking adms was associated with developing diabetes .
adm use was defined as a time - dependent categorical variable up to each time point evaluated with three levels : never used , used intermittently ( at least once but not always ) , and used continuously ( at all visits ) . at each successive time point , the value of the variable was calculated based on all previous time points , including the current measurement . a significant interaction between adm use and treatment groups
time - dependent covariate analyses ( 1 ) were used to model the above covariates and diabetes risk with adjustment for factors associated with an increased risk of developing diabetes ( race / ethnicity , age , sex , education , fasting plasma glucose at baseline , weight at baseline , and weight change during the study ) .
we now present data over a median of 10 years since randomization , including the time period of the first phase of the dpp that was reported previously ( 1 ) .
therefore , these analyses are not independent of the previous study and should be considered an extension , not a replication , of those findings .
when other factors associated with an increased risk of developing diabetes were controlled , continuous adm use during the dpp / dppos ( compared with no use ) was strongly associated with diabetes risk ( fig .
1 ) for participants in the placebo ( hra 2.34 [ 95% ci 1.324.15 ] and lifestyle ( 2.48 [ 1.454.22 ] ) arms . in the placebo arm ,
the association between intermittent adm use and diabetes trended toward statistical significance ( 1.34 [ 0.991.81 ] ) . in the metformin arm ,
there was a significant difference between the lifestyle and metformin arms in the association between adm and diabetes risk .
results did not change when we excluded participants taking adms that are more likely to cause weight gain ( tricyclic and tetracyclic agents ) . for each treatment group , from left to right , the three bars represent no exposure , intermittent exposure , and continuous exposure .
the current findings extend those of our earlier report ( 1 ) , although over the longer follow - up in this study that includes the dppos , we did not find an association with intermittent adm use and diabetes risk in the lifestyle arm .
these findings are similar to those in a previous report that long - term use of adm increased the risk of developing diabetes ( 4 ) .
other studies ( 5,6 ) , have also reported increased adm - related diabetes risk .
the association between adm use and diabetes risk remained significant when likely mediators of this association were controlled .
this association could represent a medication effect , or it could reflect differences not assessed in the study between adm and non - adm users .
although there is no obvious explanation for this latter finding , one study found that metformin induces the release of 5-hydroxytryptamine through neuronal and nonneuronal mechanisms and thus increases insulin secretion ( 7 ) .
metformin also appears to ameliorate inflammation ( 8) , and inflammatory markers appear to be associated with depression ( 9 ) .
strengths of the current study include the large , racially and ethnically diverse population , the definitive assessment of glucose tolerance and diabetes , repeated collection of data on both adm use and depression symptoms , and repeated assessment of metabolic diabetes risk factors .
we were also able to more accurately determine the onset of diabetes a considerable advance over studies that rely on clinical records that may not accurately capture when diabetes actually developed .
potential dpp participants were excluded if they were taking bupropion or any adm in greater than the lowest therapeutic dose , so the study sample was not representative of the general population .
the absolute number of diabetes cases in the continuous adm group was quite small ( placebo n = 18 , lifestyle n = 15 ) . during the dpp / dppos we did not collect data on adm dosage , so we could not examine the association between dosage and diabetes risk .
strengths of the current study include the large , racially and ethnically diverse population , the definitive assessment of glucose tolerance and diabetes , repeated collection of data on both adm use and depression symptoms , and repeated assessment of metabolic diabetes risk factors .
we were also able to more accurately determine the onset of diabetes a considerable advance over studies that rely on clinical records that may not accurately capture when diabetes actually developed .
potential dpp participants were excluded if they were taking bupropion or any adm in greater than the lowest therapeutic dose , so the study sample was not representative of the general population .
the absolute number of diabetes cases in the continuous adm group was quite small ( placebo n = 18 , lifestyle n = 15 ) . during the dpp / dppos we did not collect data on adm dosage , so we could not examine the association between dosage and diabetes risk .
| objectiveto assess the association between antidepressant medicine use and risk of developing diabetes during the diabetes prevention program ( dpp ) and diabetes prevention program outcomes study ( dppos).research design and methodsdpp / dppos participants were assessed for diabetes every 6 months and for antidepressant use every 3 months in dpp and every 6 months in dppos for a median 10.0-year follow-up.resultscontrolled for factors associated with diabetes risk , continuous antidepressant use compared with no use was associated with diabetes risk in the placebo ( adjusted hazard ratio 2.34 [ 95% ci 1.324.15 ] ) and lifestyle ( 2.48 [ 1.454.22 ] ) arms , but not in the metformin arm ( 0.55 [ 0.251.19]).conclusionscontinuous antidepressant use was significantly associated with diabetes risk in the placebo and lifestyle arms . measured confounders and mediators
did not account for this association , which could represent a drug effect or reflect differences not assessed in this study between antidepressant users and nonusers . |
primary hyperparathyroidism ( phpt ) in multiple endocrine neoplasia type i ( men1 ) has a penetrance rate of nearly 100% by the age of 50 years .
the underlying pathology in men1 phpt differs from sporadic disease ; parathyroid hyperplasia is present rather than a monoclonal adenoma .
differences in the natural history are evident ; patients present at a younger age ( 2025 years ) with early onset of complications for example , affected women have a reduced bone mineral density ( bmd ) by the age of 35 years .
effective management of men1 phpt is advisable to reduce complication rates ; a significant reduction in bmd has been observed in men1 patients with uncontrolled phpt compared to those with controlled phpt
. surgical cure of men1 phpt is difficult to achieve ; multiple gland hyperplasia , involvement of more than 4 glands and ectopic locations such as the mediastinum dictate the need for thorough preoperative localisation .
there remains controversy over the optimal surgical intervention ; total parathyroidectomy necessitates the use of long - term activated vitamin d and the potential complication of hypercalciuria . whilst subtotal parathyroidectomy avoids this ,
further hyperplasia is likely to occur in residual parathyroid tissue ; recurrence rates of 50% were reported at 812 years post successful subtotal parathyroidectomy .
cinacalcet is a potential medical alternative ; by allosterically modulating the calcium sensing receptor on the pth cell , it increases sensitivity to extracellular calcium and down - regulates pth secretion .
it is licensed for the management of secondary hyperparathyroidism and parathyroid carcinoma [ 4 , 5 ] . in primary hyperparathyroidism ,
reductions in serum calcium and to a lesser extent serum pth levels have been demonstrated [ 6 , 7 ] , but the likelihood of surgical cure in sporadic disease usually avoids the need for additional medical intervention .
we reviewed the clinical data of nine patients treated with cinacalcet for men-1 phpt with institutional board approval .
the cohort consisted of three males , five females , aged 2038 years at diagnosis ( table 1 ) .
two patients were unable to undergo surgery ; one due to severe learning difficulties and the second due to an anxiety disorder , and cinacalcet was commenced as primary treatment .
pretreatment serum calcium levels ranged 2.622.91 mmol / l , median 2.76 mmol / l ( reference range 2.152.65 mmol / l ) , and pth levels ranged 4.836.5 pmol / l , median 15.9 pmol / l ( reference range 1.36.8 pmol / l ) .
all patients deficient in 25-hydroxy vitamin d were commenced on supplements and achieved levels within the laboratory reference range prior to commencement of cinacalcet .
six out of eight patients exhibited complications of phpt : reduced bmd in five patients , ( t score of less than 2.5 ) , renal calculi in four patients , and renal dysfunction in four patients ( > 25% reduction in creatinine clearance ) .
two patients had no complications of hyperparathyroidism but were under the age of 50 ; all patients therefore fulfilled criteria for treatment as determined by the consensus on the management of asymptomatic primary hyperparathyroidism 2002 .
cinacalcet was generously provided by amgen on a compassionate - use basis to the hospital for no charge .
after a product license was obtained in the uk for use in renal failure - related hyperparathyroidism , it was prescribed on an off label basis at 30 mg twice daily .
the dose was subsequently reduced in four patients : two due to clinical response and two due to side effects . due to the pharmacokinetics of cinacalcet
, all serum calcium and pth measurements were taken predose according to a defined protocol .
as steady state drug levels are achieved after 7 days , results of the first clinical assessment ( three months postcommencement ) were used for comparison .
the nonparametric wilcoxon signed ranks test was performed for the comparison of the variables between the studied groups because of the small sample size .
all patients achieved normocalcaemia on cinacalcet with a median posttreatment serum corrected calcium of 2.35 mmol / l , range of 2.132.54 mmol / l .
serum calcium reduced by a median of 0.68 mmol / l , range of 0.100.68 mmol / l , and was statistically significant ( p = .012 ) ( figure 1(a ) ) .
serum pth reduced by median of 5.05 pmol / l , range of 0.724.8 pmol / l , ( p = .012 ) ( figure 1(b ) ) .
analyses were repeated following removal of a potential outlier ( patient number 8) to confirm statistical significance ; this confirmed a significant reduction in serum pth ( p = .018 ) .
a significant increase was noted in serum phosphate ( p = .012 ) but no change was found in 24-hour urinary calcium measurements ( table 2 ) .
a comparison was made between pre- and 2 hours post cinacalcet pth measurements for the 5 individuals in whom results were available ; no significant difference was detected ( p = .345 ) .
cinacalcet was well tolerated by six patients ; two experienced gastro - intestinal side effects and one subsequently discontinued cinacalcet .
duration of treatment was 1035 months with maintenance of biochemical control achieved in seven patients ; the eighth patient defaulted from clinical follow up .
incomplete clinical data precluded the statistical comparison of disease end points ; however , no difference was noted in bmd for the five patients reassessed .
patients with a history of renal calculi had been successfully treated previously ; none demonstrated recurrent stone formation .
our data demonstrate that cinacalcet is effective at significantly lowering serum calcium and pth levels but insufficient data were available to draw conclusions regarding disease end points .
control of serum calcium and pth in men1 phpt patients treated with surgery is associated with an increase in bmd which suggests that aiming for biochemical control is an appropriate therapeutic strategy in these patients . where surgery is not possible or has failed to control men1 phpt
existing medical options are limited ; bisphosphonates are effective in improving bone density but have no significant effect on serum corrected calcium or pth levels .
recently demonstrated the effectiveness of long acting octreotide in the management of men1 patients with primary hyperparathyroidism and duodeno - pancreatic neuroendocrine tumour .
however , long - term adverse metabolic sequelae are likely to outweigh its benefits for primary hyperparathyroidism alone [ 1113 ] .
we have demonstrated a more impressive reduction in serum pth ( median 35.5% , range 3.2567.9% ) compared to studies of cinacalcet use in sporadic phpt ( mean reduction 7.6% ) .
timing of pth samples in relation to cinacalcet dosing does account for potential variability in results ; a reduction of 37% has been demonstrated at 2 hours postdose , with recovery of predose levels by 8 hours .
such pharmacodynamics were not evident in our cohort ; no significant difference was detected between predose and 2-hour postdose pth measurements for the five patients in whom results were available .
the reasons for the enhanced pth response seen in our cohort are not clear ; we postulate that the underlying pathology may be of importance .
men1 hyperparathyroidism is invariably due to chief cell hyperplasia rather than a monoclonal adenoma . it may be possible that the expression of calcium sensing receptors differs between the two phenotypes and this may influence biochemical response to cinacalcet , although data to support this are currently lacking .
previously published data highlighted the theoretical concern of increased urinary calcium excretion with cinacalcet use , due to the direct action at the calcium sensing receptors in the kidney .
the overall reduction in serum calcium appears to counteract this effect and significant changes in urinary calcium excretion have not been demonstrated in primary hyperparathyroidism . in view of the theoretical concern ,
it is the authors ' policy to measure 24-hour urine calcium levels as part of the patient 's annual clinical assessment in addition to regular assessment of serum calcium , phosphate , and pth measurements .
effective control of serum calcium and pth levels in men1 phpt is an appropriate therapeutic strategy to reduce the early onset of associated complications .
where surgery has been noncurative or is not possible , cinacalcet may provide a medical alternative ; this is supported by our study and a recent case report of a 30-year - old woman who maintained biochemical control after 1 year of cinacalcet for management of men1 hyperparathyroidism .
longer - term prospective studies are needed to further evaluate clinical effectiveness , safety , and tolerability . | background . management of multiple - endocrine neoplasia type 1- ( men1- ) associated hyperparathyroidism is associated with high recurrence rates and high surgical morbidity due to multiple neck explorations .
cinacalcet , a calcimimetic agent licensed for the treatment of secondary hyperparathyroidism and parathyroid carcinoma , may provide a medical alternative for the management of these complex patients .
methods .
a prospective audit was performed of eight patients ; three males and five females , aged 2038 at diagnosis .
two patients commenced cinacalcet as primary treatment and six had previous surgery .
six patients had complications of hyperparathyroidism : renal calculi , renal dysfunction , and reduced bone mineral density .
all were commenced on cinacalcet 30 mg bd for men1 associated hyperparathyroidism ; doses were subsequently reduced to 30 mg od in four patients . results .
significant reductions were observed in serum calcium and pth measurements .
serum calcium reduced by a median of 0.35 mmol / l ( p = .012 wilcoxon signed rank ) . serum pth levels decreased by a median of 5.05 pmol / l ( p = .012 ) .
there was no change in urine calcium .
duration ranged from 1035 months with maintenance of control .
cinacalcet was well tolerated by six patients ; one experienced nausea and one experienced diarrhoea .
conclusion .
cinacalcet is an effective and well - tolerated medical treatment for the management of complex primary hyperparathyroidism . |
solvent
polarity strongly affects the mechanism of photoinduced electron transfer
( et ) reactions . in polar solvents ,
the process usually involves complete
et from the electron donor to the acceptor , thereby forming spin - correlated
radical ion pairs ( rips ) . in nonpolar solvents ,
the formation of excited - state
charge transfer complexes , so - called exciplexes , is often observed .
expectedly , in moderately polar solvents , both quenching reactions
may contribute simultaneously and radical ions can result from direct
et as well as dissociation of the exciplex . due to similar spectral footprints of ion pairs and exciplexes ,
the magnetic field effect ( mfe ) on the exciplex emission provides
a versatile tool for the study of this intricate dynamics .
the approach
has been applied to homogeneous solvents as well as under conditions
of preferential solvation , which often occur in binary solvent mixtures
of solvents of vastly different polarity .
the term preferential solvation subsumes nonspecific
and specific interactions of solutes with specific components of binary
solvent mixtures .
it often induces microheterogeneity in the solvent ,
which is characterized by the spatially nonuniform distribution of
the solvent components in the vicinity of polar or ionic solutes .
these microclusters of polar solvent molecules have a pronounced effect
on the mutual diffusion and reactivity of radical ion pairs and , thus ,
the mfes they elicit .
so far , microheterogeneous solvation has only
been studied by steady - state mfe measurements .
this severely limits the insights in the
radical pair dynamics in these systems , because only time - resolved
mfe measurements allow one to discriminate the initial reaction products .
the mfe relevant to this study results from the radical
pair mechanism . in short , the overall singlet and triplet
states of the radical pair
are coherently interconverted by the hyperfine
interactions ( hfis ) of the magnetic nuclei of the radicals .
an external magnetic field will remove the degeneracy of the three
electronic triplet sublevels ( t0 and t ) of the spin - correlated pair ( in the absence of significant exchange
or electron electron dipolar coupling ) .
when the energy separation
between these states exceeds the size of the mixing interactions ,
t can not mix with the singlet state s. in this way ,
the external magnetic field reduces the probability of intersystem
crossing in the radical pair and , thus , alters the relative concentrations
of singlet and triplet reaction products ( see scheme 1a ) .
the hyperfine - induced spin mixing
between s and t0 and t can only efficiently
proceed when the electron exchange interaction , which energetically
splits the s from the t - states , is smaller in magnitude than the hyperfine
interactions . owing to the fact that the electron exchange interaction
depends exponentially on the distance between the radical ions ,
this
implies that only diffusively separated radical ions can undergo s / t - conversion .
eventually , the singlet rip concentration can be detected through
the emission of the exciplex , which is produced by singlet rip cage
recombination ( see scheme 1b ) . in the absence of an external magnetic field
( b0 = 0 ) , the singlet ( s ) and all three triplet ( t0, ) states are interconverted by the radical hyperfine interactions
( hfi ) . in the presence of a sufficiently large magnetic field b0 , the t states can not mix
with the s state .
the
red and orange arrows refer to the radiative processes of the exciplex
and the locally excited fluorophore emissions , respectively . as a consequence of this mechanism ,
any factor influencing
the rip molecular dynamics may affect mfe features such as the magnitude
of the mfe observed under saturating field conditions and the b1/2 value , which gives the field intensity delivering
half the saturation mfe . in this way
, the exciplex system can serve
as a magneto - fluorescent probe , sensitive to the local dielectric
heterogeneities of binary solvents . indeed , using magnetic - field - affected - reaction - yield
( mary ) line broadening measurements
, the b1/2 values were found to vary strongly with the solvent composition
in microheterogeneous solvents .
solvent mixtures composed
of toluene ( to ) and dimethyl sulfoxide ( dmso ) have been studied in
detail .
studies of the magnetic isotope effect revealed
no direct transfer of spin density on solvent molecules . instead , the observed effects were entirely
due to the radical pair dynamics .
in general , the rp lifetime is reduced
in the microheterogeneous to / dmso environment due to an enhanced cage - effect
facilitating rp reencounters . as the dmso concentration and thus the
relative macroscopic permittivity , s ,
is increased ,
the lifetime of the rip increases due to a smaller depth of the dielectric
traps .
this is a consequence of the rips evading swift recombination
by their diffusive escape from the trap .
accordingly , the extrapolated b1/2 values in the limit of zero donor concentration , b1/2(0 ) , are larger than expected for long - lived
rps but decrease with increasing macroscopic dielectric constant ,
in contrast to what is seen in homogeneous solvents .
nath and co - workers have recently suggested that two populations
of exciplexes exist for the pyrene / n , n - dimethylaniline donor acceptor system in comparably polar
thf / dmf and benzene / acetonitrile solvent mixtures .
the authors argue that the effect is attributed to ( incomplete )
relaxation of the solvent shell surrounding the contact ion pair .
the aforementioned steady - state approaches usually do not take the
exciplex kinetics into account .
the mechanism of fluorescence quenching
by electron transfer is , however , ambiguous ; i.e. , the initial quenching
products are a rip via distant et ( pathway 2b of scheme 1b ) or the exciplex ( pathway
2a ) .
several studies have illustrated the use of time - resolved mfes
of the exciplex to identify the initial quenching products in homogeneous
solvents and solvent mixtures . in this work ,
we describe
the solvent polarity dependence of the time - resolved mfe in homogeneous
and micro - heterogeneous binary solvent mixtures as measured by time - correlated
single photon counting ( tcspc ) . the well - studied donor
n , n - dimethylaniline ( quencher)/9,10-dimethylanthracene
( fluorophore ) serves as a magnetosensitive probe ( see scheme 1c ) .
our study gives detailed
insights into the peculiar rp dynamics in microheterogeneous solvents .
throughout this work ,
we use the terms preferential solvation
and microheterogeneous medium interchangeably , although ,
strictly speaking , the former refers to specific and nonspecific solute
solvent
interactions , while the latter signifies the nonuniform solvent structure ,
which the former induce . in the present context
n , n - dimethylaniline
( dma , aldrich 99.5% ) was distilled under reduced pressure and subsequently
handled under an argon atmosphere .
the concentration of the fluorophore
was constant at 1.5 10 m , while that of
the quencher was 0.06 m. solutions were prepared in septa - sealed fused
silica cuvettes .
all solutions were purged with solvent - saturated
nitrogen gas for 15 min to remove dissolved oxygen before adding the
quencher through the septum using hamilton syringes . a series of solvent
mixtures of propyl acetate ( pa , aldrich 99.5% , distilled under reduced
pressure , s = 6 ; this and all subsequently reported
values refer to a temperature of 295 k ) and butyronitrile ( bn , fluka
99% , distilled under reduced pressure , s = 24.7 )
and of toluene ( to , fluka 99% , distilled under reduced pressure , s = 2.38 ) and dimethyl sulfoxide ( dmso , aldrich 99.9% , used
as received , s = 46.4 ) with widely varying dielectric
constants , s , were prepared .
the dielectric constants
of these mixtures are given by eq 1 and eq 2 for the pa / bn and to / dmso systems , respectively ( at 295 k):12here , wpa is the mass fraction of pa and xdmso is the mole fraction of dmso .
the homogeneous mixtures
of pa / bn allow systematic variation of the solvent dielectric constants
within a range of 624.7 ( at 295 k ) while keeping the viscosity
( ) and the refractive index ( n ) almost constant .
the pekar factor , = ( 1/
1/s ) ( 1/n
1/s ) , which governs the outer - sphere electron transfer
reorganization energy , increases only moderately with increasing permittivity . for the microheterogeneous mixtures of to / dmso ,
the solvent dielectric constant
was varied from 4.3 to 15.5 . the viscosity
and the bulk pekar factor of to / dmso mixtures slightly increase
with increasing dmso concentration .
we
are not aware of a microheterogeneous solvent mixture for which this
could be avoided . using
the experimental setup described in ref ( 32 ) ,
the exciplex emission was recorded at 550 nm
under continuous excitation of the sample at 374 nm . for each sample
,
the fluorescence intensities were acquired three times under conditions
of zero and saturating magnetic field exposition for 60 s each .
field - on
and field - off measurements were recorded in an alternating fashion .
the excitation slit width was 2 nm , the emission slit width 6 nm ,
and the spectrometer time constant 1 s. measurements were conducted
at 295 k. the three repetitions were analyzed independently , and the
experimental errors were obtained according to the method described
in ref ( 32 ) .
the absolute
mfe , ss , was evaluated from3here , i(em , bsat ) and i(em , b0 = 0 ) are the mean intensities at
em in a saturated magnetic field ( bsat = 62 mt ) and in the absence of an additional magnetic
field , respectively .
if(em , b0 ) is the residual emission
of the locally excited fluorophore at em in the
absence of quencher .
ic and i0 are the intensities of prompt emission of the fluorophore
in the presence and absence of the quencher , respectively , which have
been obtained from the decomposition of the fluorescence spectra .
time - resolved data of the mfes on the exciplex
were obtained by the tcspc technique . in order to investigate the
effect of an external magnetic field on the exciplex emission ( figure 1 ) , a saturating magnetic
field (
the fluorophore
is excited at 374 nm by a laser diode ( picoquant , ldh - p - c-405 ) , and
a 550 nm long - pass filter in front of the detector ensured that only
the exciplex luminescence was detected . a detailed description of
the experimental setup is given in refs ( 1 ) and ( 2 ) .
time - resolved exciplex emission ( upper panel ) of the 9,10-dimethylanthracene
( 1.5 10 m)/n , n - dimethylaniline ( 0.06 m ) system in a to / dmso mixture at s = 7.3 in the absence ( gray ) and presence ( blue ) of an external
magnetic field ( 62 mt ) monitored with a long - pass filter ( lp550 ) after
pulsed excitation at 374 nm .
in the presence of an external magnetic
field , the delayed emission of the exciplex is enhanced .
the time
evolution of the magnetic field effect i(t ) ( lower panel ) was obtained by taking the difference of
the exciplex emission time traces in the absence and presence of an
external magnetic field .
the red solid line is calculated from the
model , eq 6 . in the lower
panel , t = 0
ns coincides with the pulse excitation ;
in the upper panel , the emission traces are shifted by approximately
15 ns to longer times .
the raw data of a typical time - resolved mfe measurement are
shown in figure 1 .
the time traces rise with a time constant of approximately 2 ns , almost
independent of the magnetic field intensity .
the decay kinetics of
the exciplex emission includes the dissociation into free ions and
recombination giving rise to delayed exciplex emission .
the time - resolved
mfe ( tr - mfe ) is given as the difference in the exciplex emission intensity ,
i(t ) , in the absence and
presence of the external , biasing magnetic field:4 in order to determine the mfe , the amplitudes within
the first nanosecond after the excitation pulse were matched .
we integrated
the time traces so obtained to determine the steady - state mfe of the
exciplex , tr , from the time - resolved mfe measurements:5scheme 1b shows the pertinent reaction pathways for fluorescence quenching
by electron transfer .
the abscissa can be expressed as the projection
of a two - dimensional reaction coordinate comprising the distance between
the fluorophore and the quencher and the outer - sphere electron transfer
reaction coordinate .
an increase in the intensity of the exciplex emission
( 6 ) is due to the enhancement of the population of the singlet rip ,
which can reform the exciplex via ( 4 ) .
the singlet rip can be indirectly
generated via exciplex dissociation ( 3 ) , e.g. , following a quenching
reaction yielding the exciplex ( 2a ) , or directly , via a remote electron
transfer reaction ( 2b ) .
note that the et reactions preserve the overall
spin of the reactant pair ; i.e. , both the exciplex and the rip are
formed as singlet entities .
the external magnetic field gives rise
to an increase in the singlet rip probability and hence the exciplex
via pathway 4 .
as a consequence of the exciplex dissociation here
being a slow process , the mfes generated by the direct et route ( 2b )
will be observed on a faster time scale than those formed by the exciplex
route ( 2a ) . in this way , time - resolved mfes of the exciplex emission
can distinguish the reaction channels populating the magneto - sensitive
rp state ( 2b versus 2a ) . to simulate the experimental data
,
we used the model introduced in ref ( 2 ) . in this model ,
the probability that the radical pair
system exists as an exciplex , e(t , b0 ) , is given by6where i is the
probability that the rip is initially generated ( pathway 2b in scheme 1b ) , kd denotes the rate constant of exciplex dissociation , ri is the distance of rip formation via distant
et , and r(t , b0|ri ) is the probability that a
rip formed at distance ri at t = 0 has recombined by time t. re refers to the contact distance of the fluorophore and
quencher , at which the transition of the rip to the exciplex ( or contact
ion pair ) occurs .
e = 1 i is the initial exciplex probability ( pathway 2a in scheme 1b ) , and e is the
intrinsic exciplex lifetime ( without dissociation ) .
the contributions
to the exciplex probability in eq 6 can be described as follows : the first term is the
probability that the exciplex is formed initially , while the second
term accounts for the probability that the initially generated rip
reforms an exciplex at t. the third term describes
the probability that the exciplex dissociated at time is reformed
at t , and the last term models the depopulation of
the exciplex by dissociation ( kd ) and
radiative / nonradiative decay with the rate constant .
r(t , b0|ri ) is field dependent and has been calculated in the low - viscosity
limit as described in detail in refs ( 1 ) and ( 2 ) .
the radical pair was assumed to diffuse in a potential
of mean force approximately accounting for the microheterogeneous
environment .
this potential was calculated following an approach based
on the d e0 theorem
as outlined in refs ( 18 ) and ( 20 ) .
note that
more elaborate schemes of treating the diffusion - influenced reversible
exciplex kinetics have been derived on the basis of the integral encounter
theory . while also comprehensively applicable to highly viscous mixtures ,
this approach is difficult to employ for radical pairs with a multitude
of magnetic nuclei ( as is the case here ) and beyond the scope of the
current presentation .
figure 2 illustrates the microheterogeneous medium structure to clarify
typical length scales and the extent of the local enrichment of the
polar component as predicted on the basis of the continuum model from
ref ( 20 ) .
illustration
of the structure of the microheterogeneous solvent surrounding a radical
ion pair ( contact distance : 6.8 ) as predicted by the continuum
solvation model described in ref ( 18 ) .
( a ) local mole fraction of dmso in dmso / toluene
mixtures of bulk concentration xdmso =
0.2 ( left ; s = 7.3 ) and 0.4 ( right ; s = 13 ) .
( b ) deviation of the local dielectric constant from
the macroscopic dielectric constant for the two solvent mixtures from
part a. the plots show contours through a plane containing the two
radical centers .
figure 3 illustrates the dependence of the mfe of the dmant / dma system
on the solvent dielectric constant , s , of the microheterogeneous
to / dmso mixture as determined from steady - state ( ss ) and time - resolved ( tr ) measurements ( upper panel ) .
the lower panel gives a comparison of the s dependence
for the binary solvent mixtures of pa / bn ( homogeneous ) and to / dmso
( microheterogeneous ) .
this observation suggests that in
both types of experiments the same photochemical reactions are probed .
in fact , in view of the low light intensities and low concentrations
employed in these experiments , bulk processes such as f - pair reactions
and processes involving fluorophore triplets ( triplet triplet
and triplet doublet pair reactions ) are not expected to contribute
to the observed mfes here . instead , the mfes on the exciplex result
exclusively from the effect of an external magnetic field on the s / t
mixing in the geminate radical pair .
the onset of the mfe is found
at s = 6 ( with = 0.1% ) and s = 4.3 ( with = 1.6% ) in the pa / bn and to / dmso mixture , respectively .
in the homogeneous pa / bn mixtures ,
the mfe is small for s < 10 but rises sharply for s
13 to attain its maximum value around s
18 ( 11% ) . for larger solvent polarities ,
it decreases slightly as
a larger population of the radical pairs dissociates indefinitely
without reencountering ( within the coherence time of the radical pair ) .
in the microheterogeneous to / dmso mixtures ,
the onset of the mfe occurs
at a lower bulk permittivity and the maximal value ( 14.5% ) is already
observed at s = 8.3 .
in essence , the mfe appears
to report a more polar environment than would be expected on the basis
of the bulk permittivity .
these peculiarities in the mfes can be explained
on the basis of a dielectric enrichment of the polar component ( dmso )
in the vicinity of the magneto - sensitive rip . as a consequence , the
effective dielectric constant , eff , of the enriched
solvation shell
this specific solvation increases the reencounter
probability of the geminate rp without impeding the spin - conversion
by too tight binding , which in homogeneous solvents of low polarity
is seen to hamper the mfe by confining the radical pairs to configurations
with large exchange coupling . as a consequence , larger mfes are possible
in the microheterogeneous environments as compared to homogeneous
solutions .
solvent permittivity dependence of the magnetic field effect of
the 9,10-dimethylanthracene / n , n - dimethylaniline
exciplex determined from steady - state ( blue filled triangles ) and
time - resolved mfe ( red filled stars with barely visible error bars
reflecting the statistical error of the registration process ) measurements
in solvent mixtures of to / dmso ( upper panel ) .
the lower panel compares
the mfe in the homogeneous and microheterogeneous solvent mixtures . for various dielectric constants ,
the time - resolved mfes are shown in figure 4 together with least - squares fits applying
the model given by eq 6 .
the maximum of the tr - mfes occurs in the range from 10 to 75 ns
after photoexcitation , with larger values occurring at lower dielectric
constants . for all samples ,
the mfes reached the noise level of the
experiment within 400 ns after excitation .
experimental time - dependent
magnetic field effects ( i ) at different dielectric
constants , s , in pa / bn ( top panel ) and to / dmso ( middle
panel ) solvent mixtures for the system 9,10-dimethylanthracene / n , n - dimethylaniline .
the bottom panel compares
the tr - mfes of the exciplex in pa / bn and to / dmso mixtures of the same
dielectric constant ( s = 13 ) .
the exciplex lifetime , e , is one of the central parameters characterizing the time
evolution of the mfe .
we have determined e from
the initial decay of the tcspc traces of the exciplex , for which the
rp recombination is negligible .
figure 5 shows that the apparent exciplex lifetime decreases
with increasing bulk dielectric constant , s , in
both binary solvent mixtures .
furthermore , as expected in view of
the above discussion , the exciplex lifetimes are considerably smaller
in the to / dmso mixtures as compared to the iso - bulk dielectric pa / bn
mixtures .
note also that the exciplex is an excited charge - transfer
complex with correspondingly large dipole moment . as a consequence
,
its formation is expected to enhance the diffusive enrichment of polar
solvent molecules in its surrounding . in this way , the exciplex can
act as a catalyst to its own dissociation ( pathway 3 in scheme 1b ) .
as the exciplex lifetime
is considerably larger than the characteristic time of solvation ,
these dynamic aspects can however not be resolved here .
permittivity
dependence of the exciplex lifetimes of the 9,10-dimethylanthracene / n , n - dimethylaniline exciplex in pa / bn ( red
circles ) and to / dmso mixtures ( blue squares ) .
the exciplex kinetics are also characterized by the association
constant ka = ka / kd ( top panel in figure 6 ) and the exciplex dissociation quantum yield
d = kde ( middle panel in figure 6 ) .
d was estimated from the dependence of
e on dielectric constants assuming that the intrinsic ,
radiative and nonradiative decay rates are independent of solvent
composition .
ka has a strong effect on
the shape , i.e. , the temporal evolution , of the time - resolved mfes
and can thus be extracted from the experimental data by least - squares
fitting .
following this approach as detailed in ref ( 2 ) , ka and d were obtained as a function of s . in general , d increases with s , likely because polar environments reduce the exciplex stabilization
free energy by increasing the reorganization energy .
this effect is indeed found and much more pronounced in the microheterogeneous
environment as compared to the homogeneous one . for to / dmso ,
the exciplex
dissociation quantum yield approaches d = 1 for
a bulk dielectric constant as low as s = 8 , while
for pa / bn mixtures this is only the case at s
22 .
dependence of the association constant , ka , the dissociation quantum yield of the exciplex , d , and the initial rip formation , i , on the dielectric
constants , s , of homogeneous ( pa / bn ) and microheterogeneous
( to / dmso ) solvent mixtures .
the filled circles and squares with error
bars have been determined from the experimental data by modeling the
tr - mfe .
likewise , the association constant ka is expected to decrease with polarity , as is clearly
evidenced in figure 6 for the homogeneous pa / bn solutions . while ka in general also decreases with increasing polarity for to / dmso ,
it is nearly constant in the range from s = 8 to
12 .
this surprising behavior suggests that ka increases in this region in parallel to kd such that ka is approximately
constant .
this can likely be attributed to an increased association
rate brought about by the microheterogeneous solvation impeding the
separation of the radical ions with respect to the homogeneous environment .
just as ka , the probability of the
initial rip formation , i , governs the time evolution
of mfes of the exciplex and was extracted from the experimental data
by least - squares fitting .
the extracted i values are also shown in figure 6 as a function of the dielectric constant .
the data reveal that , for the dmant / dma system with moderate free
energy of charge separation ( get = 0.28 ev ) , the direct exciplex formation
( pathway 2a in scheme 1b ) contributes at all dielectric constants in homogeneous and microheterogeneous
environments .
furthermore , the probability of distant et quenching
increases with increasing solvent polarity . note that the requirement
to detect the exciplex luminescence limits the accessible s range to the indicated range ; beyond the respective limits ,
the exciplex emission is insufficient for the accurate determination
of i . in both solvent mixtures ,
for to / dmso , this
is the case for s 9 , and for pa / bn , for
s 20 , in agreement with the general bearing .
distant electron transfer quenching is more favored in polar solutions ,
where it leads to a better solvation of the reaction products ( rips ) .
this holds true despite a minor increase in the reorganization energy
resulting from the increasing polarity . in the low - viscous solutions
studied here ,
the diffusive approach of the reactants is fast enough
compared to the intrinsic electron transfer rate to always form a
contact complex ( exciplex ) at the contact distance .
as a consequence , i is smaller than unity , even for the most polar and hardly
emissive solutions .
in
this work , we have employed time - resolved mfe measurements to study
the exciplex and rip dynamics of the dmant / dma system in homogeneous
and microheterogeneous solvent mixtures of various bulk permittivities .
we use a model accounting for the reversible exciplex dissociation
to identify the peculiarities resulting from microheterogeneous solvent
environments in solvent mixtures of to and dmso .
the exciplex dynamics
and the initial quenching products depend strongly on the solvent
properties . in microheterogeneous solvents , specific solvation of
the exciplex and rip gives rise to an environment that is significantly
more polar than that observed in homogeneous solvents of comparable
bulk permittivity . for low permittivities
, this brings about a larger
dissociation quantum yield of the exciplex , a lower exciplex lifetime ,
and a larger probability that the system undergoes distant electron
transfer quenching .
specific solvation furthermore impedes the radical
separation such that , in the permittivity region from 7 to 15 , the
association constant decays only slowly with the solvent polarity
in the to / dmso mixtures . in both environments ,
the probability of
the initial formation of rips is always less than unity ; i.e. , the
exciplex formation contributes at all s . in microheterogeneous
solution ,
the local concentration of dmso in the solvation shell around
the exciplexes and rips plays an important role in the exciplex kinetics
and the fluorescence quenching mechanism . together with earlier works ,
this study demonstrates that time - resolved mfe studies have the potential
to provide detailed insights into the reaction dynamics of rips and
exciplexes .
since the reaction dynamics of the geminate radical pair
are very sensitive to small changes in the local dielectric environment ,
the technique is here recognized as a versatile tool in revealing
and characterizing the phenomenon of specific solvation in solvent
mixtures . | external
magnetic fields can impact recombination yields of photoinduced electron
transfer reactions by affecting the spin dynamics in transient , spin - correlated
radical pair intermediates .
for exciplex - forming donor
acceptor
systems , this magnetic field effect ( mfe ) can be investigated sensitively
by studying the delayed recombination fluorescence . here
, we investigate
the effect of preferential solvation in microheterogeneous solvent
mixtures on the radical pair dynamics of the system 9,10-dimethylanthracene
( fluorophore)/n , n - dimethylaniline
( quencher ) by means of time - resolved magnetic field effect ( tr - mfe )
measurements , wherein the exciplex emission is recorded in the absence
and the presence of an external magnetic field using time - correlated
single photon counting ( tcspc ) . in microheterogeneous environments ,
the mfe of the exciplex emission occurs on a faster time scale than
in iso - dielectric homogeneous solvents .
in addition , the local polarity
reported by the exciplex is enhanced compared to homogeneous solvent
mixtures of the same macroscopic permittivity .
detailed analyses of
the tr - mfe reveal that the quenching reaction directly yielding the
radical ion pair is favored in microheterogeneous environments .
this
is in stark contrast to homogeneous media , for which the mfe predominantly
involves direct formation of the exciplex , its subsequent dissociation
to the magneto - sensitive radical pair , and re - encounters .
these observations
provide evidence for polar microdomains and enhanced caging , which
are shown to have a significant impact on the reaction dynamics in
microheterogeneous binary solvents . |
the description of the external morphology was based on the air - dried material observed under a dissecting microscope .
the specimen used in this study was deposited in the lichen herbarium of korean lichen research institute ( kolri ) in sunchon national university , korea .
specimens from natural history museum and institute , chiba ( cbm ) , japan were also examined for comparison purposes .
chemical analysis was made by hplc method ( yoshimura , 1994 ) using ymc - pack ods - a column and eluent solvent of meoh : h2o : h3po4 (= 80 : 20 : 1 , v / v / v ) .
thallus tightly adnate , margine lobate , center subcrustoseareolate , lobes sublinear , 0.2~1.2 mm wide .
external morphology : thallus saxicolous , subcrustose , more or less lobate at the center with clearly lobed margins , 2~6 cm broad , pale yellowish green ( fig .
1a ) ; lobes subirregular , variable 0.4~1.1 mm wide , sparingly branched , flat to more or less convex , contiguous to subimbricate ( fig .
1b ) ; upper surface continuous , emaculate , shiny , moderately isidiate , the isidia subglobose to cylindrical , darkening at the tips , unbranched ( fig .
apothecia initially aspicilioid but soon emergent and sessile , the disk brown , 0.5~0.8 mm in diameter ; spores 5~6 9~11 m .
chemistry : medulla k+ yellow ; sticitic acid , norstictic acid and usnic acid ( fig .
2 ) habitat and ecology : scattering on the rock surface of exposed splash zone along sea coastal lines with other lichens such as xanthoria and caloplaca sp .
distribution : it is the most widespread species in the genus on the world level and occurs commonly on sandstones in south africa , south west africa , brazil , uruguay , australia , hong kong , taiwan , japan and india .
east asian specimens ( taiwan , japan and korea ) were mainly found along sea coast .
, on seaside rock ( splash zone ) , hur 06 - 0001 ; japan , wakayama - ken , higashi - muro - gun , koza - cho , moritozaki point , 5 m alt . , on seaside rock ( supertidal zone ) , harada 16130 .
ohshima island ( yashiro island ) yamaguchi - ken , ohshima - gun , touwa - cho , yun , hokibaba point , 6 m alt .
remarks : this species is easily recognized by chemistry ( stictic acid ) and the presence of isidia .
only two species of k. microscopica and k. saxeti are isidate , but the former has no sticitic acid ( k- ) .
thallus tightly adnate , margine lobate , center subcrustoseareolate , lobes sublinear , 0.2~1.2 mm wide . upper surface continuous , emaculate , often pruinosed . lower surface with rhizoid or forming lamellae .
external morphology : thallus saxicolous , subcrustose , more or less lobate at the center with clearly lobed margins , 2~6 cm broad , pale yellowish green ( fig .
1a ) ; lobes subirregular , variable 0.4~1.1 mm wide , sparingly branched , flat to more or less convex , contiguous to subimbricate ( fig .
1b ) ; upper surface continuous , emaculate , shiny , moderately isidiate , the isidia subglobose to cylindrical , darkening at the tips , unbranched ( fig .
apothecia initially aspicilioid but soon emergent and sessile , the disk brown , 0.5~0.8 mm in diameter ; spores 5~6 9~11 m .
chemistry : medulla k+ yellow ; sticitic acid , norstictic acid and usnic acid ( fig .
2 ) habitat and ecology : scattering on the rock surface of exposed splash zone along sea coastal lines with other lichens such as xanthoria and caloplaca sp . together
distribution : it is the most widespread species in the genus on the world level and occurs commonly on sandstones in south africa , south west africa , brazil , uruguay , australia , hong kong , taiwan , japan and india .
east asian specimens ( taiwan , japan and korea ) were mainly found along sea coast .
, on seaside rock ( splash zone ) , hur 06 - 0001 ; japan , wakayama - ken , higashi - muro - gun , koza - cho , moritozaki point , 5 m alt . , on seaside rock ( supertidal zone ) , harada 16130 .
ohshima island ( yashiro island ) yamaguchi - ken , ohshima - gun , touwa - cho , yun , hokibaba point , 6 m alt .
remarks : this species is easily recognized by chemistry ( stictic acid ) and the presence of isidia .
only two species of k. microscopica and k. saxeti are isidate , but the former has no sticitic acid ( k- ) . | karoowia saxeti was recorded during the lichen field expedition in southern part of korea in 2006 .
the lichen was found on the rock surface along coastal line .
this species was easily recognized by chemistry ( k+ yellow ) and the presence of isidia .
thallus was saxicolous , subcrustose , more or less lobate at the center with clearly lobed margins , 2~6 cm broad and pale yellowish green .
thalli lobes were irregular , variable , up to 1.0 mm wide , not branched , flat to more or less convex and contiguous to subimbricate .
upper surface of the thalli was continuous , emaculate , moderately isidiate .
the isidia was subglobose to cynlindrical , darkening at the tips and unbranched .
low surface of the thalii was black with a spongy rhizoidal and lamellar layer .
hplc analysis proved the presence of stictic acid ( k+ yellow ) , norstictic acid and usnic acid .
this is the first record of the species in south korea . |
school - associated firearm violence among
children and adolescents is a national public
concern .
the objective of this study was to
determine the accessibility of firearms , methods
of firearm access and firearm safety knowledge
among middle and high school students in orange
county , california .
after permission from school officials and
parents was obtained , a 24-question survey was
distributed to 176 students in grades 6 through 12
at four schools in orange county .
, cross tabulations were
performed to determine which factors were
associated with access to guns , having fired a
gun , and firearm possession at school .
seventy - seven ( 45% ) were male , 121 ( 69% ) hispanic ,
and 171 ( 94% ) were of middle income .
four
participants ( 2.3% ) admitted to gang involvement ,
47 ( 26.7% ) had fired a gun . those more likely to
have fired a gun appeared to be non - hispanic males
( p= 0.001 ) .
older students and those in grades 9 to 12
were more likely to have access to a gun ( p=
0.01 ) , which they stated could be obtained from
their homes , friends or relatives ( 4.5% to 22% ) .
two ( 1.1% ) students stated that they had thought
of using a gun at school .
one hundred one students
( 62% ) were taught firearm safety by their
parent(s ) .
almost half of the students in this study
acknowledged that they could gain access to a gun
and two students had thought about using a gun at
school .
firearm education , safety and counseling
are of paramount importance to ensure safety among
school youths . | objective : school - associated firearm violence among
children and adolescents is a national public
concern . the objective of this study was to
determine the accessibility of firearms , methods
of firearm access and firearm safety knowledge
among middle and high school students in orange
county , california.methods:after permission from school officials and
parents was obtained , a 24-question survey was
distributed to 176 students in grades 6 through 12
at four schools in orange county .
data was
collected over a 12-month period beginning in
february 2003 .
data analysis was presented in
proportions .
in addition , cross tabulations were
performed to determine which factors were
associated with access to guns , having fired a
gun , and firearm possession at school.results:the mean age of participants was 16.1 years .
seventy - seven ( 45% ) were male , 121 ( 69% ) hispanic ,
and 171 ( 94% ) were of middle income .
four
participants ( 2.3% ) admitted to gang involvement ,
47 ( 26.7% ) had fired a gun . those more likely to
have fired a gun appeared to be non - hispanic males
( p= 0.001 ) .
seventy - five ( 43% ) reported access to
a gun .
older students and those in grades 9 to 12
were more likely to have access to a gun ( p=
0.01 ) , which they stated could be obtained from
their homes , friends or relatives ( 4.5% to 22% ) .
no students admitted to bringing a gun to school .
two ( 1.1% ) students stated that they had thought
of using a gun at school .
one hundred one students
( 62% ) were taught firearm safety by their
parent(s).conclusion : almost half of the students in this study
acknowledged that they could gain access to a gun
and two students had thought about using a gun at
school .
firearm education , safety and counseling
are of paramount importance to ensure safety among
school youths . |
are used along the history ; however nowadays new advanced techniques have decreased the actual use of corneal tattooing .
new techniques like corneal grafting , keratoplasty techniques , and colored contact lenses may be used for treatment of corneal opacities instead of corneal tattooing .
corneal tattooing may be required in patients with corneal opacities or cataract with blind eyes with no hope in vision regain ; intraocular surgery like keratoplasty and cataract surgery may be risky and expensive with no sight value with expected complications .
most patients suffer much with psychological problems and persist to alter the cosmetic appearance of their eyes .
samuel lewis ziegler , in his optical indications of corneal tattooing that included albinism , iridodialysis , coloboma , aniridia , or diffused nebulae of the cornea .
corneal tattooing also may be used in patients with useful vision to reduce agonising glare associated with large iris defect like surgical iridectomies or iris loss after ocular traumas .
corneal tattooing in old history is firstly described by galen of pergamum , a roman physician and philosopher , in 150 ad , and aetius in 450 ad described the same technique to change the shape of disfigured eyes with leukomatous opacities .
galen and aetius in their technique cauterise the desired area of corneal surface with a heated stilet , and then they would apply the dye to the eye and they used different types of dyes such as powdered nutgalls and iron or copper sulphate .
this technique was used only in blind eyes with corneal leukoma with no vision . in the 2nd century
galen described corneal tattooing ; however the technique is not mentioned until 1869 , when louis von wecker described a new technique by use of black india ink to tattoo a disfiguring leukoma of the eye . in his technique
he firstly used topical cocaine as anesthetic agent , then a thick black india ink solution was put over the cornea , and a multiple puncture by a grooved needle was used to insert pigment into the corneal tissue .
taylor in his new technique used a bundle of needles to introduce the dye in the corneal tissue and tattooing of the eye . in 1901 , nieden used the idea of fountain pen to introduce a tattooing needle in a technique similar to the edison electric pen .
he found that this electrical needle introduces the dye more rapidly and reliably than traditional methods of tattooing .
used china ink by use of a small funnel that he fixed to the cornea and then put into the instrument and tattoo was done with a needle .
morax described a new technique by splitting the corneal tissue into two vertical layers ; then dye was introduced between two layers ; and strong compression by dressing over the eye was done . in the current study single intrastromal injection of china painting ink ( rotring ) by insulin syringe in the cornea of male rabbits was done and follow - up was for six months after injection .
study design .
this study was applied on 10 male rabbits weighing 1.7 to 2.8 kg with mean 2.3 kg . the china painting ink ( rotring ) ( figure 1 ) sterilized in a steam autoclave for 20 minutes at 121c in sterile glass infusion bottles .
all the rabbits underwent the following technique : general anaesthesia by intraperitoneal 9 mg / kg ketamine hydrochloride .
few minutes later under the surgical microscope intrastromal injection of 0.1 ml of rotring china painting ink by 27-gauge insulin syringe at the center of the cornea in one eye was done ( figures 2 and 3 ) .
clinical follow - up at the second day , third day , and every week after injection and after six - month scarification was done with enucleation of all injected eyes for further histological study . for control study we enucleated two nonstained eyes from the same animals for histological study .
both eyes of each animal was fixed in 10% buffered formalin and processed for paraffin blocks .
5 m sections were cut and stained with hematoxylin and eosin ( h&e ) for routine histological study .
this study was carried out according to guidelines for animal experimentation of the institutional animal care and use committee .
this study was applied on 10 male rabbits weighing 1.7 to 2.8 kg with mean 2.3 kg ; at the time of injection all corneas show corneal oedema with cloudy appearance due to stromal hydration which resolved within hours leaving dark stained coloration at the center of the cornea at the site of injection ( figure 4 ) .
all rabbits show early postoperative conjunctival redness with lacrimation which resolved early in few days after injection . in the follow - up period extended for six months no serious complications occurred with no corneal ulceration and no signs of iritis or intraocular inflammation . in the follow - up period
two rabbits died ( 20% ) , one after 3 months and the other after 4.5 months with 8 surviving until 6 months when the follow - up period finished and rabbits were scarified for corneal histological study .
the death rate of rabbits is the normal death rate in baladi rabbits in the summer season when the study was done . during the follow - up period
all injected corneas maintain the same shape and color of the blackish color of the injected ink with no fading ( figure 5 ) .
the stratified squamous nonkeratinized layer appeared with its basal columnar cells , intermediate polygonal cells , and superficial squamous cells .
the corneal epithelium rested on a uniform basement membrane underneath ( bowman 's layer ) .
the substantia propria was formed of regularly arranged collagen fibers and scattered spindle shaped stromal cells in between .
descemet 's membrane appeared just beneath the stroma and was covered by descemet 's endothelium ( figure 6 ) .
light microscopic examination of the injected cornea showed linear clumps of blackish pigment particles between anterior two - thirds and posterior one - third parallel to corneal stroma .
the rest of corneal layers showed no abnormalities so they were more or less similar to control with no changes in endothelial cells ( figure 7 ) .
the pigment showed cohesiveness at all of its length . no inflammatory cellular infiltration or neovascularization
the corneal tattooing is an old technique that may be used in cosmetic or optical indications ; the cosmetic reason is like disfiguring corneal opacity or white pupil in cases of cataract in blind eye when reconstructive surgical procedures are with no functional improvement or carry a great risk of great complications like endophthalmitis and atrophia bulbi .
tattooing may be a valuable cosmetic alternative specially with increasing difficulty in wearing a tinted cosmetic contact lens or a bulbar shell .
although tattooing of the cornea is an old technique with many modifications it is not widely used with difficulty to choose the optimal dye and optimal technique . along the history
many different types of inks were used for the dyeing of the cornea . in the current study we used rotring china painting ink which is cheap , easily available , easy in storage , and easy in sterilization as it is aqueous solution .
it is available in plastic container and easy to obtain from stationary with different colors . in this study
vassileva and hristakieva reported that ink from india is the most commonly used , providing safe and long - lasting effects .
kobayashi and sugiyama used metallic colors in powder form , various organic dyes , and uveal pigment from animal eyes .
two different methods exist : chemical dyeing with gold or platinum chloride and carbon impregnation .
sekundo et al . in their comparative study between chemical and carbon impregnation reported that chemical dyeing is easier and quicker than carbon impregnation , but it fades more rapidly than nonmetallic tattooing .
the most common chemical dyes that are generally used are platinum or gold chloride , which provide a jet black stain .
carbon impregnation includes the use of most common inks like india ink , chinese ink , lamp black ink , and other organic dyes .
vassileva and hristakieva , faculty members at bulgaria universities , reported that india ink is a safe and long - lasting ink when properly diluted and it is widely used in corneal tattoo nowadays .
many different techniques may be used for corneal staining . in the current study we used a single intrastromal injection of 0.1 ml of the dye with a 27-gauge insulin needle at the center of the cornea at the middle of the stroma depending on the sense of the surgeon with decreased risk of corneal ulceration or recurrent erosion .
in one such method , the physician inserts the ink into the cornea stroma by multiple punctures , covering the needle with ink each time . in pitz
technique , they would cover a three - edged spatula needle with ink before each puncture ; multiple puncture was done .
theobald would firstly inject the cornea with a needle and then rub in the ink with a daviel curet .
khan and meyer introduced a new method of tattooing ; this described technique started by removing of the corneal epithelium at the area of opacity firstly ; then a piece of filter paper soaked in platinum chloride 2% would be placed by the physician onto the area for two minutes ; after that a second piece of filter paper soaked in hydrazine 2% is applied for 25 seconds .
thomson in his new technique in corneal tattooing of disfiguring corneal opacities used a small steel pen designed by joseph gillott , with the point converted into the cutting surface .
the barrel of the pen would receive amount of tattooing ink for the entire operation , trying to avoid the need to refill the ink or to recover the needle with ink .
a new technique lamellar keratectomy with tattooing gives good results with homogeneous application of the stain [ 1215 ] .
dermatography - like manner of tattooing has two disadvantages : firstly , the multiple puncture into the corneal stroma , enhancing activation of phagocytosis , with fading of the stain .
the second disadvantage is that the multiple puncture of bowman 's layer might promote recurrent corneal erosion [ 6 , 16 ] . recently ,
mechanical microkeratome and femtosecond lasers have been used to create the lamellar stromal pocket for corneal tattooing .
although femtosecond laser - assisted corneal tattooing demonstrates good efficacy and safety , it is very expensive . in comparison to our study microkeratome and femtolaser
lin et al . in their study of corneal tattooing , through anterior stromal puncture for managing painful bullous keratopathy and after follow - up period of 26 months , recurrent bullae formation occurred in 3 of 31 patients ( 9.68% ) who had undergone corneal tattooing that may match with our study in absence of inflammatory cells in histological analysis . in the current study we noticed no fading in the color of the corneal tattooing and the size and shape of pigmentation are the same all over the follow - up period .
the explanation may be due to the single corneal injection decreasing the inflammatory reaction which decreases phagocytosis or vascularization responsible for fading out of the dye and this clinical result is proved by histological analysis .
six - month follow - up is considered as short follow - up period and fading of the ink may occur later on .
kim et al . in their previous long - term study on the conventional method reported that the main problem with corneal tattooing is fading color over time : 12 of 147 patients developed faded color or opaque eyes following tattooing .
park et al . in their results agreed with kim et al . in the long - term fade rate
the disadvantage of our technique of single intrastromal injection is the unpredictable size and shape of the tattooing in the stroma ; however masking of different types and shapes of opacities is suggested specially if small localized lesion in the cornea is present .
the limitation of our technique for blind eyes is mandatory due to unpredictable size and shape of the single intrastromal dye injection .
the histological results proved that the china ink collected in a sheath parallel to the corneal surface extracellularly between the collagen fibers .
the position of the ink was between anterior two - thirds and posterior one - third .
the pigment particles were adhesive and made a linear aggregation without diffusion in the surrounding extracellular matrix . in the present work
there were pigment granules in the cytoplasm of some corneal fibroblast at the nearby storm .
this might enforce the ability of the stain to be permanent and stable in the cornea as the pigment could persist in these cells for a long period . in agreement with these findings
found the nonmetallic pigment particles in the keratocyte in the corneal stroma but not the metallic ones in patient cornea .
the ability of fibroblast to acquire a phagocytic activity to ingest the pigment as an attempt to protect the cornea from damage by foreign nontoxic materials was established . in a study by kobayashi and
sugiyama a 64-year - old woman who underwent keratopigmentation for corneal opacities in both eyes 53 years ago was examined by confocal microscope ; the examination showed scattered highly reflective particles in a geographic pattern were observed in the superficial stroma near bowman layer .
in addition , clusters of highly reflective granules were in the midstroma to superficial stroma .
the absence of the inflammatory cells and neovascularization could support the safety of the stain that we choose for the process of tattooing .
moreover , the stromal cells secrete anti - inflammatory cytokines to prevent the reaction which affect the clarity of the corneal tissue .
intrastromal injection of rotring china painting ink in corneas of rabbits is safe , easy , simple , and effective technique and the histological results in the present study gave sufficient evidence that pigment is safe to use in patient for the future work .
however six - month follow - up is a short period to evaluate the possible toxicity or fading of the dye .
further study in human corneas in indicated patients is advised with longer follow - up period . | background . many patients with corneal opacity or complicated cataract in blind eye
ask for cosmoses . in this study we tried to investigate the staining of corneas of male rabbits by rotring china painting ink and to study the histological changes . method .
10 eyes of 10 male baladi egyptian rabbits were injected ( 0.1 ml ) intrastromally in the cornea by the use of china painting ink ( rotring tinta china ) through insulin syringe ( 27-gauge needle ) by single injection ; clinical follow - up is for 6 months and lastly the rabbits were scarified and the stained eyes were enucleated for histological analysis
. results .
clinically the stain was stable in color and distribution in corneas with no major complications .
histological results of the stained rabbit corneas showed blackish pigmentation in the corneal stroma without any inflammatory cellular infiltration .
some fibroblast cells had pigment granules in their cytoplasm in the adjacent layers .
conclusion .
corneal staining by china painting ink is effective and safe in staining of male rabbits cornea ; however further study in human corneas with longer follow - up period is advisable . |
carney syndrome ( cs ) is an autosomal dominant multiple neoplasia syndrome that includes cardiac , endocrine , cutaneous , and neural tumors .
although the age at presentation may vary , cs is usually diagnosed in young patients , predominantly in female gender .
cardiac myxomas seen in the course of cs are most often encountered in the left atrium .
extra - cardiac manifestations include pigmented skin lesions , cutaneous myxomas , adrenal cortical disease , myxoid mammary fibroadenoma , and testes tumors in male patients .
pituitary adenoma , melanotic schwannomas , and thyroid disease may be encountered in lower percentages . in this case report , we describe a middle - aged female patient who underwent surgery with the diagnosis of a large left atrial myxoma associated with cs .
a 46-year - old female patient was admitted to our clinic with palpitation , cough , and exertional dyspnea .
physical examination revealed pigmented lesions , especially scattered in the neck , chest , and extremities .
the thyroid gland was mildly enlarged on palpation , but thyroid ultrasonography did not reveal any nodular or diffuse enlargement .
she had been followed up with fibroadenomas located at the upper quadrant of the right breast .
echocardiography revealed a left atrial mass , 6 4 cm in size , originating from the interatrial septum that was protruding into the left ventricle through the mitral valve during diastole ( figure 1 ) .
peak pulmonary artery pressure was measured to be 65 mmhg , which was accompanied by mild to moderate tricuspid regurgitation .
biochemical and hormonal parameters as well as thyroid hormone levels were within normal limits , except for mildly elevated hepatic enzymes ( serum glutamic oxaloacetic transaminase [ sgot ] = 55
iu / l , serum cortisol = 10 g / dl , insulin like growth factor [ igf]-1 = 202 ng / dl , growth hormone [ gh ] = 5 ng / dl , and oral glucose tolerance test with 100 gr glucose : fasting blood glucose level = 110 mg / dl ; 1 hour blood glucose level = 170 mg / dl ; 2 hour blood glucose level = 153 mg / dl and 3 hour blood glucose level = 143 mg / dl ) . left atrial myxoma ( white arrow ) seen on echocardiographic evaluation
four chamber view genetic analysis of the patient ( especially the prkar1a gene ) could not be accomplished because of the lacking laboratory facilities in a newly established medical center .
the aorta was cross - clamped and the heart was arrested with cold blood cardioplegia .
left atriotomy was performed.a large encapsulated soft and lobulated left atrial myxoma , 6 4 cm in size , was attached to the interatrial septum with a broad base .
the tumor was excised from the interatrial septum with its pedicle ( figure 2 ) .
postoperative echocardiography revealed mild tricuspid regurgitation with a peak pulmonary artery pressure of 30 mmhg .
the postoperative course was uneventful and the patient was discharged at the 5th postoperative day without any complication .
we described a middle - aged patient with left atrial myxoma associated with concomitant clinical manifestations , which are components of cs : pigmented skin lesions and fibroadenomas of the breast .
the overall lifespan of patients with cs is decreased , and cardiac causes of death are the most common among other etiologies .
our patient s age was higher , which may reflect the late onset of the disease as well as late admission to a medical center .
since more than half of the cases are familial , application of rigorous screening protocols are suggested for the first - degree relatives of the affected patients . our patient s first - degree relatives were screened for the cardiac and other manifestations of cs .
the recurrence rate of the myxomas encountered in the course of cs is higher than that of the sporadic cases and this is an important issue since it may require multiple surgical interventions .
postoperative short and long - term follow - up controls are crucial in these patients .
cs is a complex genetic multiple endocrine neoplasia syndrome with various components relating to different organ systems .
different clinical properties are well known and diagnostic criteria are defined concerning the large variety of these manifestations .
cardiac myxomas are a corner stone of this disease since cardiac manifestations and related complications account for the majority of the mortality seen in the course of cs . | abstractcarney syndrome ( cs ) is an autosomal dominant multiple neoplasia syndrome that includes cardiac , endocrine , cutaneous , and neural tumors .
cardiac myxomas can be seen in the course of cs .
a 46-year - old female patient was admitted to our clinic with palpitation , cough , and exertional dyspnea .
physical examination revealed pigmented lesions , especially scattered in the neck , chest , and extremities .
echocardiography revealed a left atrial mass , 6 4 cm in size , originating from the interatrial septum that was protruding into the left ventricle through the mitral valve during diastole .
the tumor was excised from the interatrial septum with its pedicle .
the patient was discharged at the fifth postoperative day without any complication .
cardiac myxomas are a cornerstone of this disease since cardiac manifestations and related complications account for the majority of mortality seen in the course of cs . |
chile , an upper middle - income country in south america , has seen increases in the prevalence of overweight and obesity , well - established risk factors for conditions such as cancer , cardiovascular disease , and diabetes [ 1 , 2 ] . in 1987 ,
the prevalence of excess weight among 6-year - olds in chile was 13% ; by 2000 , it had reached 27% . according to a 2012 report by the organization for economic cooperation and development ( oecd ) ,
25.1% of chilean adults are obese and , among chilean children aged 517 years , 27.1% of girls and 28.6% of boys are overweight or obese .
like excess weight , sleep disorders , particularly sleep apneas , have been associated with hypertension [ 5 , 6 ] , coronary artery disease , myocardial infarction [ 8 , 9 ] , heart failure , and diabetes .
although reports have been published on the prevalence of obesity and of sleep apnea in chilean adults and young children [ 4 , 11 ] , few reports have focused attention on the prevalence of obesity and sleep apnea among young adults , particularly college students transitioning from adolescence into adulthood . moreover ,
the college years are often characterized by insufficient sleep , increased consumption of energy drinks and caffeinated beverages , and irregular meal and sleep patterns , which can have important consequences for overall health and wellbeing [ 1215 ] . to address the paucity of literature on the epidemiology of obstructive sleep apnea ( osa ) and adiposity indices among college students in chile , and to lay groundwork for developing health promotion and disease prevention strategies
we investigated osa risk and the extent to which high risk for osa was associated with overweight , general obesity , and central obesity in this population .
the study was conducted between december 2010 and june 2011 at four colleges in the magallanes region of chile : universidad tecnologica de chile , universidad del mar , universidad de magallanes , and universidad santo tomas .
of the 994 full - time undergraduates who participated in the study , we excluded students who were above 35 years old or missing information on age , sleep apnea ( i.e. , the berlin questionnaire ) , or adiposity measures ( n = 78 ) . the final sample consisted of 916 students aged 18 to 35 who had complete exposure and outcome information .
interested students were invited to meet in a large room or an auditorium where they were informed about the study purpose and procedures and invited to complete anonymous questionnaires requesting demographic , lifestyle , and sleep - related information .
students who gave informed consent and completed the questionnaires were invited to participate in a brief physical examination during which trained research nurses took cardiometabolic and anthropometric measures including height , weight , blood pressure ( bp ) , pulse rate , waist circumference ( wc ) , and hip circumference ( hc ) .
all study procedures were approved by the institutional review boards of centro de rehabilitacin club de leones cruz del sur , punta arenas , chile , and the university of washington , usa . the harvard school of public health office of human research administration , usa , granted approval to use the anonymized dataset for analyses .
osa risk was evaluated using the berlin questionnaire . since it was first developed in 1996 , the berlin questionnaire has been validated and used extensively in clinical and epidemiologic research globally including latin america [ 1723 ] .
numerous validation studies have reported moderate to high consistency between results of the berlin questionnaire and parameters of polysomnography , particularly respiratory disturbance index ( rdi ) > 5 and apnea - hypopnea index ( ahi ) 5 , especially within clinical populations .
category 2 assesses frequency of feelings of fatigue or tiredness after waking as well as sleepiness while driving .
category 3 ascertains information about obesity and hypertension [ 17 , 19 ] . in the first two categories , a participant is given a positive score if he or she responds with
yes or experiences frequent symptoms ( more than 3 to 4 times per week ) in two or more questions within that category .
for category 3 , a participant is given a positive score if he or she is obese ( bmi 30 kg / m ) or has a history of hypertension .
participants with positive scores in two or more categories are classified as having a high risk for osa .
body mass index ( bmi ) was calculated as weight in kilograms divided by height in square meters ( kg / m ) .
categories of bmi were defined according to the world health organization ( who ) criteria ( underweight : < 18.5 kg / m ; normal : 18.524.9 kg / m ; overweight : 25.029.9 kg / m ; and obese : 30.0 kg / m ) .
central obesity was evaluated using the international diabetes federation ( idf ) criteria for south american men and women , that is , wc 90 cm ( for men ) and wc 80 cm ( for women ) .
waist - to - hip ratio ( whr ) was calculated by dividing wc by hc .
whr was further categorized by quartile distribution and central obesity defined as whr in the top quartile .
each anthropometric measurement was taken twice , and the average was used in data analyses .
lifestyle and behavioral characteristics included moderate or vigorous physical activity ( yes versus no ) , cigarette smoking status ( never , former , or current ) , alcohol consumption within the past year ( no versus yes ) , and use of more than one energy or stimulant drink per week ( no versus yes ) . energy or stimulant drinks were defined as beverages used to boost energy levels , increase alertness , and enhance cognition and mood .
examples of these beverages include coffee , yerba mate , cola , red bull , and dark dog .
other variables included self - rated health ( good versus poor ) and systolic and diastolic bp .
high risk for obstructive sleep apnea ( osa ) , defined as described above , was the exposure and the outcomes of interest were overweight , general obesity , central obesity , bmi , wc , hc , and whr .
first , we examined the frequency distributions of sociodemographic , lifestyle , and behavioral characteristics of the students .
characteristics of participants were summarized using counts and percentages for categorical variables and mean values ( standard deviations ) for continuous variables .
student 's t - tests and chi - square tests were used to calculate bivariate differences for continuous and categorical variables , respectively .
we examined the frequency distribution of osa risk according to sociodemographic , lifestyle , and behavioral characteristics .
multivariate linear regression models were used to assess the associations of high osa risk with bmi , wc , hc , and whr .
multivariate logistic regression models were used to determine odds ratios ( or ) and 95% confidence intervals ( ci ) of the association of high osa risk with general obesity ( bmi 30 kg / m ) , central obesity according to the idf criteria , and whr in the top quartile .
confounding variables were considered a priori on the basis of their hypothesized relationship with osa and adiposity .
potential confounders included age , sex , year in college , alcohol consumption , use of energy drinks , cigarette smoking status , self - rated health , bp , and participation in moderate or vigorous physical activity .
we conducted stratified analyses to evaluate the extent to which , if at all , associations of high osa risk with overweight , general obesity , and central obesity differed by sex , elevated bp , and subjects ' self - rated health .
all statistical analyses were performed using statistical analysis software ( sas , version 9.3 ; sas institute , cary , nc ) .
of the 916 students included in the analysis , 69.5% were females and the average reported age was 21.8 ( 3.3 ) years . approximately 7.8% were classified as having high risk for osa as determined using previously published scoring and classification scheme of the berlin questionnaire .
approximately 28.3% of students were overweight ( bmi : 2529.9 kg / m ) and 12.8% had general obesity according to who criteria ( bmi 30 kg / m ) .
using the idf definition , it was determined that 42.7% of students had central obesity ( wc 90 cm for men or wc 80 cm for women ) .
high risk for osa was associated with age , poor self - rated health , and cigarette smoking status .
however , high risk for osa was not associated with sex , year in college , systolic bp , diastolic bp , alcohol consumption , participation in moderate to vigorous physical activity , or consumption of more than one energy or stimulant drink per week ( table 1 ) .
prevalence of high osa risk was highest in the obese bmi category ( figure 1 ) and in individuals who were over 21 years old ( figure 2 ) .
table 2 shows the results of the fully adjusted models of the linear regression analyses .
high osa risk was statistically significantly associated with higher bmi ( : 3.25 ; standard error : 0.63 , p < 0.001 ) and whr ( : 0.03 ; standard error : 0.01 , p = 0.02 ) .
high osa risk was also associated with higher wc ( : 7.32 ; standard error : 1.54 , p < 0.001 ) and hc ( : 5.00 ; standard error : 1.41 , p < 0.05 ) .
high risk for osa was associated with almost 10-fold increased odds of general obesity ( or 9.96 ; 95% ci 4.4222.45 ) compared to low risk for osa .
students with high osa risk also had 2.78-fold odds of central obesity ( or 2.78 ; 95% ci 1.435.40 ) .
however , the odds of high risk for osa were not elevated by overweight status ( or 0.89 ; 95% ci 0.352.23 ) .
those with high risk for osa were also more likely to be in the top quartile of whr ( i.e. , whr 0.8875 ) , although statistical significance was not achieved ( or 1.45 ; 95% ci 0.712.95 ) ( table 3 ) .
similar strong positive associations between high risk for osa and general obesity ( bmi 30 kg / m ) were evident within strata of sex ( male or female ) , bp ( nonelevated or elevated ) , and self - rated health ( good or poor ) .
high risk for osa was not associated with overweight in strata of sex , bp , or self - rated health . for central obesity
high risk for osa was associated with central obesity only in men ( or 4.66 ; 95% ci : 1.3316.39 ) , in individuals with elevated bp ( or 7.34 ; 95% ci : 2.3822.59 ) , and in those with good self - rated health ( or 2.60 ; 95% ci 1.285.28 ) while the findings in women and those with poor self - rated health were suggestive of a positive though not statistically significant association ( table 4 ) .
in this study of chilean college students , 7.8% were classified as having high risk for osa as defined by the berlin questionnaire and there was a high prevalence of overweight ( 28.3% ) , general obesity ( 12.8% ) , and central obesity ( 42.7% ) .
high osa risk was strongly and positively associated with general obesity and central obesity , but not with overweight .
although the exact pathway linking osa and obesity remains somewhat unclear , it is recognized that obesity contributes to airway collapse during sleep by causing increased fat deposits around the upper airway , thus narrowing it and diminishing the activity of the muscles in that region [ 2831 ] .
conversely , sleep apnea may contribute to excess weight and obesity through sleep loss and daytime sleepiness as apneic individuals rouse often to resume breathing and reenable unobstructed air flow .
moreover , insufficient sleep has been associated with increased energy need and food intake . on balance
, available evidence suggests mechanisms that may underlay bidirectional relationships between increased adiposity and osa .
we found strong positive associations of high osa risk with general obesity , central obesity , bmi , and whr .
these findings are largely consistent with findings from numerous prior studies [ 3340 ] . in the wisconsin sleep cohort study ,
a 10% weight gain was associated with approximately 32% increase in ahi as assessed by polysomnography . in their study of patients at primary health care centers in dubai , mahboub et al . found that approximately 70% of those at high risk for osa had a bmi 30 kg / m while about 75% of the low risk group had bmi < 30
likewise , blondet et al . found in a study of middle - aged puerto ricans that among men with bmi < 30 kg / m , 98% had high risk for osa compared to 50% among nonobese men .
in addition , the authors noted that 70% of women with bmi > 28 kg / m were at high risk for osa compared to only 28% of those with bmi < 28 kg / m .
the prevalence of high risk for osa among students with general obesity in our study was substantially higher ( 28.3% ) compared to that in normal weight ( 4.6% ) and overweight ( 5.4% ) students .
although participants in many studies examining obesity and osa risk are older and heavier than our population , significant positive associations between sleep apnea and obesity have also been found in pediatric and adolescent populations [ 4346 ] . while we found no association between overweight bmi category and high risk for osa in our sample , peppard et al . observed a positive association between overweight bmi category and ahi in the wisconsin sleep cohort study . despite our finding of no association ,
overweight students should be targeted for interventions as these students are at higher risk for obesity in the near future compared to normal weight students .
the prevalence of high risk for osa in our sample ( 7.8% ) is higher than what is reported among us young adults .
for instance , authors of a study among 1,845 students enrolled in a southeastern us college reported a prevalence of 4% as assessed using the sleep-50 survey .
however , our finding is lower than high osa risk estimates reported for us adults ( 26% ) who participated in the 2005 sleep in america poll .
we found no significant difference in frequency of osa risk by sex ( 9.3% for men and 7.1% for women ; p = 0.25 ) within our sample , although other investigators have shown that men have a higher risk for osa compared to women the main hypothesis being that men tend to have more fat deposits in the upper part of the body , that is , around the neck , trunk , and abdomen .
the prevalence of general obesity in our study ( 12.8% ) was relatively low when compared to the prevalence reported for chilean adults by the oecd ( 25.1% ) or that determined from a multistage cluster sampling of adults 40 years old in santiago , chile ( 31.7% ) [ 4 , 11 ] .
however , the combined prevalence of overweight and obesity ( i.e. , bmi 25 kg / m ) in our study was greater than that observed in a study of 3,461 chilean students aged 1724 years ( 41.1% versus 19% ) .
when we examined the frequency of bmi 25 kg / m by age within our sample , there was still a high prevalence of excess weight in the respective groups : 1824 year - olds ( 39.5% ) and 2535 year - olds ( 48.4% ) ; p = 0.04 .
these high frequencies of overweight and obesity in young adulthood are of concern as they may have implications for the development of cardiometabolic conditions in later life .
first , numerous validation studies have reported moderate to high consistency between results of the berlin questionnaire and parameters of polysomnography , the gold - standard for diagnosing sleep disorders .
second , we employed various statistical methods and assessed the relationship between high osa risk and various indices of adiposity .
third , the likelihood for misclassification of obesity was reduced as trained research nurses used standard protocols to take anthropometric measurements , thus avoiding reliance on students ' self - report .
there are some limitations that should be considered when interpreting the results of our study . given our cross - sectional study design , we are unable to determine if high risk for osa preceded obesity .
another limitation is that participants were not sampled randomly ; rather , we relied on subjects ' willingness to participate .
approximately 8% of students were excluded because of incomplete information on sleep apnea or anthropometric data .
we found no significant difference between the prevalence of poor self - rated heath among individuals in our sample and those who were excluded ( 12.1% versus 6.8% ; p = 0.29 ) nor any significant difference in the distribution of cigarette smoking status ( p = 0.28 ) .
however , excluded students tended to be older than those in our sample ( mean sd age : 23.4 5.0 versus 21.8 3.3 ; p < 0.01 ) . given that osa risk increases with age , it is possible that we missed individuals with high osa risk among those who had incomplete sleep apnea or anthropometric information .
thus , the prevalence of high risk for osa in our study could be an underestimate .
conversely , given the high prevalence of obesity within this sample , the use of odds ratios may give an exaggeration of the true estimate .
we can not exclude the possibility of residual confounding by unmeasured factors such as socioeconomic status , dietary intake ( e.g. , consumption of fruits , vegetables , or fast foods ) , or student 's course load . finally , due to the relatively small sample size
, the 95% confidence intervals for the estimates from the logistic regression and stratified analyses are quite large and imprecise .
our findings support significant positive associations of high osa risk with general obesity and central obesity .
additional longitudinal evidence is needed to establish the temporal relationship of osa and obesity . if our findings are confirmed , health care services for college students should include health promotion and disease prevention strategies about the importance of maintaining healthy weight .
strategies should also include health education modules that may be used to improve students ' knowledge about sleep disorders , as prevention and control of cardiometabolic risk factors in young adulthood may have implications for preventing and mitigating chronic disease burden in later life . | this cross - sectional study evaluates the prevalence and extent to which high risk for obstructive sleep apnea ( osa ) is associated with general obesity and central obesity among college students in punta arenas , chile .
risk for osa was assessed using the berlin questionnaire and trained research nurses measured anthropometric indices .
overweight was defined as body mass index ( bmi ) of 2529.9 kg / m2 and general obesity was defined as bmi 30 kg / m2 .
central obesity was defined as waist circumference 90 centimeters ( cm ) for males and 80 cm for females .
multivariate logistic regression models were fit to obtain adjusted odds ratios ( or ) and 95% confidence intervals ( ci ) .
prevalence of high risk for osa , general obesity , and central obesity were 7.8% , 12.8% , and 42.7% , respectively .
students at high risk for osa had greater odds of general obesity ( or 9.96 ; 95% ci : 4.4222.45 ) and central obesity ( or 2.78 ; 95% ci 1.435.40 ) .
findings support a strong positive association of high risk for osa with obesity . |
venous thromboembolism ( vte ) is a significant cause of postoperative morbidity and mortality following orthopedic surgery .
the incidence of vte , which includes deep vein thrombosis ( dvt ) and pulmonary embolus ( pe ) , following major joint arthroplasty is well defined in the literature.1 however , the reported incidence of vte following spine surgery is highly variable , with rates ranging between 0.3 and 31%.2 the variability in reported rates is secondary to heterogenous studies involving specific subgroups and various surveillance methods.2
3 although less is known about vte following spine surgery , patients undergoing spinal surgery are subject to longer operative times and often prolonged immobilization , potentially placing them at increased risk.4 in fact , recent studies have shown that the incidence of vte following spine surgery may be higher than previously reported.5
6 the issue of vte following spine surgery is even more complex because postoperative anticoagulation may increase the risk of postoperative epidural hematoma , a rare but potentially devastating complication.7
8
multiple studies have examined the incidence of vte and associated risk factors following thoracolumbar surgery.9 however , many of the studies are limited to specific cohorts of patients such as those with oncologic conditions , thoracolumbar trauma , or deformity.10
11 of the studies with broader inclusion criteria and larger patient cohorts , many utilize databases that rely on the international classification of diseases , ninth revision coding to define vte incidence and risk factors instead of clinically abstracted data limiting the utility of the obtained results.4
12 more work is needed to define vte rates following thoracolumbar surgery and to define independent risk factors that might help identify vulnerable patients who may require more aggressive screening surveillance or prophylaxis . the american college of surgeons national surgical quality improvement program ( acs - nsqip ) has been used effectively to study postoperative outcomes following spine surgery.13
14 the acs - nsqip is well suited to studying postoperative vte . the acs - nsqip tracks 30-day outcomes prospectively , and it is subject to rigorous oversight and external validation .
in addition , the acs - nsqip has been used to examine complications following thoracolumbar surgery.13 however , no previous studies have used the acs - nsqip specifically to examine vte incidence following thoracolumbar surgery , the timing of vte , and associated risk factors .
after institutional review board approval , we identified patients who underwent thoracic and/or lumbar ( thoracolumbar ) spine surgery from the 2005 to 2012 acs nsqip participant use file by using current procedural terminology codes ( see online supplementary table 1 ) .
the surgical procedures were broken down into categories to include posterior decompression , posterior spinal fusion , posterior interbody fusion ( including posterior and transforaminal interbody fusions ) , anterior interbody fusion , corpectomy , oncologic surgery , transpedicular decompression , lateral extracavitary arthrodesis , disk arthroplasty , and spinal deformity surgery including spinal osteotomies .
the acs - nsqip specifically excludes admissions for trauma , and so patients undergoing operations for spine trauma were excluded from this cohort .
a detailed list of current procedural terminology codes utilized is presented in the online supplementary table 1 .
the acs nsqip participant use file is deidentified and was therefore deemed exempt by our institutional review board .
patient demographic information including age , sex , ethnicity , and medical comorbidities was obtained in addition to preoperative laboratory values , transfusion data , operative characteristics , and length of stay data .
the incidence and timing of 30-day postoperative dvt and pe were determined using established criteria from the acs nsqip database for each of the procedural categories .
detailed data on 30-day unplanned readmissions for the cohort was available from 2011 to 2012 . following descriptive analysis , patient characteristics were broken down into categorical variables , and chi - square tests were used to determine the characteristics of patients who suffered a vte event within 30 days of surgery .
based on the findings of univariate analysis , multivariable logistic regression analysis was performed to identify the independent risk factors for vte events .
the findings were considered statistically significant when p < 0.05 . the analysis was conducted using sas software , version 9.3 ( sas , cary , north carolina , united states ) .
a total of 43,777 patients were identified in the acs - nsqip as having undergone thoracolumbar spinal surgery between 2005 and 2012 .
vte events within 30 days postoperatively occurred in 453 patients ( 1.0% ) , with 311 patients ( 0.7% ) having a dvt and 202 patients ( 0.5% ) having a pe .
overall , the mean time to diagnosis of dvt took 10.3 7.4 days , and the mean time to diagnosis of pe took 9.4 7.3 days .
the most common procedures were posterior decompression ( 65.2% ) , posterior fusion ( 15.4% ) , and posterior interbody fusion ( 8.4% ) .
the lowest vte rates were observed in the posterior decompression group with a dvt rate of 0.5% and a pe rate of 0.3% .
in contrast , the highest vte rates were in the corpectomy group with a dvt rate of 3.8% and a pe rate of 1.7% ( table 1 ) .
abbreviations : aif , anterior interbody fusion ; dvt , deep vein thrombosis ; pe , pulmonary embolus ; plif , posterior lumbar interbody fusion ; tlif , transforaminal lumbar interbody fusion ; vte , venous thromboembolism .
the average age of the cohort was 57.1 15.3 years with 48.6% of patients being female .
morbid obesity , with a body mass index ( bmi ) > 35 , was identified in 19.2% of patients .
other comorbidities identified were smoking ( 23.1% ) , diabetes mellitus ( 15.2% ) , and peripheral arterial disease ( 0.5% ) .
the majority of patients were american society of anesthesiologists ( asa ) class 1 or 2 ( 59.0% ) .
bleeding disorders were present in 1.7% of patients , with 0.3% of patients undergoing transfusion for bleeding ( 4 u ) postoperatively .
the mean operative time was 152.3 103.3 minutes with a mean length of stay of 2.9 4.0 days . from 2011 to 2012 , 28% of patients with postoperative vte underwent an unplanned readmission .
of note , age > 70 years ( 31.3% , p < 0.001 ) and african american race ( 9.7% , p <
multiple medical comorbidities were also identified as potential risk factors , including morbid obesity ( bmi > 35 , 27.8% , p < 0.001 ) , hypertension ( 62.7% , p < 0.001 ) , diabetes ( 20.8% , p < 0.001 ) , and disseminated cancer ( 9.1% , p < 0.001 ) .
several preoperative laboratories were significant including hematocrit < 33 ( 11.0% , p < 0.001 ) , international normalized ratio > 1.6 ( 72.8% , p < 0.001 ) , and platelets < 100 ( 2.0% , p < 0.001 ) .
perioperative factors that were associated with vte included longer operative times ( 233.2 149.2 minutes , p < 0.001 ) and length of stay ( 8.7 9.9 days , p < 0.001 ) .
abbreviations : bmi , body mass index ; inr , international normalized ratio ; vte , venous thromboembolism .
medical comorbidities that were predictive included disseminated cancer ( odds ratio [ or ] 1.77 , p < 0.001 ) , asa class 4 or greater ( or 1.54 , p = 0.035 ) , and bmi > 40 ( or 1.49 , p = 0.030 ) .
preoperative laboratory values predictive of vte included white blood cell count > 12 ( or 1.76 , p < 0.001 ) and albumin < 3 ( or 1.73 , p = 0.012 ) . perioperative factors including operative time > 193 minutes ( or 1.43 , p = 0.050 ) , paraplegia ( or 1.75 , p = 0.003 ) , and length of stay 6 days or greater ( or 4.07 , p < 0.001 ) . of note ,
length of stay less than 3 days was protective ( or 0.427 , p < 0.001 ) . when the spinal deformity cohort was analyzed separately , bleeding disorders were predictive of vte ( or 5.86 , p = 0.008 ) .
the rates of vte following spine surgery reported in the literature are highly variable , which is likely a result of heterogenous methodologies , many of which incorporate screening surveillance methods or evaluate specific patient subgroups.2
3 of the larger database studies available , many rely on administrative data that only captures in - hospital complications and is subject to high degrees of discordance and coding errors.4
12
15 utilization of the acs - nsqip database in this study allowed many of these limitations to be avoided .
this large cohort of 43,777 patients represents thoracolumbar surgery performed at over 400 institutions across the country .
in addition , standardized follow - up to 30 days postoperatively and rigorous oversight of the acs nsqip database ensures that the results presented are valid.16
17
18 to the authors ' knowledge , this study is the first using the acs - nsqip to examine vte specifically in a broad group of thoracolumbar patients .
although the overall rate of vte ( 1.0% ) was low in this retrospective study , there was considerable variation in vte rates by procedural group with rates as low as 0.8% in the posterior decompression group and rates as high as 5.5% in the corpectomy group .
this result is consistent with previous studies that have shown higher vte rates in patients undergoing higher morbidity surgery , such as those associated with deformity , cancer , or trauma.19
20
21 in fact , vte has been demonstrated as being higher in patients who undergo corpectomy in comparison with posterior procedures in both the cervical and thoracolumbar spine.13
22 of note , our corpectomy cohort included various anatomic approaches such as transthoracic , retroperitoneal , and lateral extracavitary approaches .
this study also demonstrates higher rates of vte in spinal deformity cases ( 2.8% ) , which is also consistent with previous reports in the literature.23
an important finding to highlight is the average time to diagnosis of vte .
given that the average length of stay was around 3 days , it is clear that a large percentage of vte events occur after discharge .
this finding is consistent with previous studies showing that nearly one - half of vte diagnoses are made postdischarge.12 these findings highlight the importance of educating patients on the signs and symptoms of vte following spine surgery and surveillance in the outpatient setting . as a result , a significant unplanned readmission rate ( 28% ) associated with postoperative vte was identified in this study .
this finding is of critical importance . although studies have shown that most vte events do not result in mortality
as spine surgery moves into an era in which reimbursement is increasingly linked to performance measures , readmissions for postoperative complications may also lead to lost reimbursement.24
several independent risk factors for vte following thoracolumbar surgery were identified .
several medical comorbidities were identified including cancer , higher asa class , and very severe obesity ( bmi > 40 ) .
cancer has been demonstrated as risk factor for vte in multiple studies in orthopedic surgery .
the reasons are likely multifactorial and are related to induced hypercoagulability , adjuvant therapies , and immobility.25 recent literature has shown obesity to be a risk factor for major postoperative complications.26 evidence has shown that obesity is a proinflammatory and prothrombotic condition .
obesity - related comorbidities including atherosclerosis and hypertension may predispose obese patients to vte.27
preoperative laboratories including white blood cell count > 12 and albumin < 3 were also identified as independent risk factors for vte .
although these results are more difficult to interpret , leukocytosis may be a surrogate for infection .
studies have shown that infection causes both venous stasis as well as a hypercoagulable state.28
29 in fact , schmidt et al demonstrated a higher rate of vte following acute respiratory and urinary tract infections.29 hypoalbuminemia is found in malnutrition and may be representative of overall poor health or medical comorbidities such as cirrhosis .
in addition , low albumin may lead to peripheral edema and possibly increased venous stasis , another known risk factor for vte.30
31
paralysis has been well demonstrated as a risk factor for vte following spine surgery.32
33 as a result , a more aggressive approach toward vte surveillance and prophylaxis is often undertaken in this patient population.8
34 other perioperative factors predictive of vte included longer operative times and length of stay .
previous studies in arthroplasty surgery have shown higher vte rates associated with longer operative times.35 although this finding could certainly be confounded by increased case complexity , it highlights the importance of monitoring for vte more carefully after longer cases . similarly ,
although this finding may represent increased stay for treatment of vte , as previously discussed , most of the vte events were diagnosed postdischarge . in addition ,
length of stay less than 3 days was protective , which indicates that other factors associated with longer lengths of stay including more complex cases , increased immobilization , and in - hospital complications other than vte may be responsible .
thus , no recommendations regarding prophylaxis , either mechanical or pharmacologic , can be made as a result of this study .
in addition , other factors of interest to surgeons such as intraoperative blood loss and use of antifibrinolytics are not captured in acs - nsqip . in conclusion ,
in this retrospective study of 43,777 patients who underwent thoracolumbar surgery , we report an overall 30-day pe rate of 0.5% and a dvt rate of 0.7% .
. a higher risk of vte was identified in patients undergoing corpectomy or deformity surgery .
the patients with length of stay 6 days or greater were more than four times as likely to suffer a vte event .
future studies directed at the development of vte risk calculators may aid in updating the current recommendations regarding vte prophylaxis .
| study design retrospective clinical study of a prospectively collected , national database .
objective determine the 30-day incidence , timing , and risk factors for venous thromboembolism ( vte ) following thoracolumbar spine surgery .
methods the american college of surgeons national surgical quality improvement program participant use file identified 43,777 patients who underwent thoracolumbar surgery from 2005 to 2012 .
multiple patient characteristics were identified .
the incidence and timing ( in days ) of deep vein thrombosis ( dvt ) and pulmonary embolus ( pe ) were determined .
multivariable regression analysis was performed to identify significant risk factors .
results of the 43,777 patients identified as having had thoracolumbar surgery , 202 cases of pe ( 0.5% ) and 311 cases of dvt ( 0.7% ) were identified .
vte rates were highest in patients undergoing corpectomy , with a 1.7% pe rate and a 3.8% dvt rate .
independent risk factors for vte included length of stay ( los ) 6 days ( odds ratio [ or ] 4.07 ) , disseminated cancer ( or 1.77 ) , white blood cell count > 12 ( or 1.76 ) , paraplegia ( or 1.75 ) , albumin < 3 ( or 1.73 ) , american society of anesthesiologists class 4 or greater ( or 1.54 ) , body mass index > 40 ( or 1.49 ) , and operative time > 193 minutes ( or 1.43 ) . los < 3 days was protective ( or 0.427 ) .
conclusions we report an overall 30-day pe rate of 0.5% and dvt rate of 0.7% following thoracolumbar spine surgery .
patients undergoing corpectomy were at highest risk for vte .
multiple vte risk factors were identified .
further studies are needed to develop algorithms to stratify vte risk and direct prophylaxis accordingly . |
urinary incontinence is a common problem with widespread human and social implications causing discomfort , shame , and loss of self - confidence . it
although several large - scale studies have focused on epidemiology of urinary incontinence in women of western countries , limited data are available from asian countries .
thus , it is of great importance to try to define prevalence and possible etiological factors with a view to subsequent prevention .
although some risk factors for incontinence have been studied , still several important predictors of incontinence remain uninvestigated .
for example , cigarette smoking has been shown to have a positive association , and the relationship between tobacco chewing , other form of nicotine intake , and tea intake , a very commonly used drink in south east asian region , has not been elucidated .
, very few studies have analyzed the risk factors for different types of urinary incontinence separately . in this cross - sectional study
, analysis has been done in india on frequency and risk factors of urinary incontinence and its various subtypes .
this single - center cross - sectional study was conducted in the department of obstetrics and gynecology at our center from august 2005 to june 2007 .
all women aged more than 18 years attending obstetrics or gynecology opd were screened for urinary incontinence by a doctor based on history and then included in the study .
the entry question was whether or not the participant experienced involuntary loss of urine . if the answer was yes the woman was categorized as having any incontinence .
subsequently , a standard questionnaire was asked by a doctor to know the clinical and demographic profile [ appendix 1 ] .
women who confirmed involuntary loss of urine in connection with coughing , sneezing , laughing , or lifting heavy items were classified as having symptoms of stress incontinence .
those whose involuntary loss of urine was connected with a sudden and strong urge to void were classified as having urge symptoms .
if there were urge and stress symptoms , then subjects were classified as having mixed incontinence .
also women employees of the same hospital who were otherwise healthy were also screened for incontinence .
subjects enrolled from opd were labeled as consulters and hospital employees were labeled as nonconsulters .
student 's t - test was used to compare means and chi - square test was used to compare discrete variables .
of the 3000 women enquired , 2804 ( 93.4% ) were consulters and 196 ( 6.5% ) were nonconsulters
of the total women having incontinence , highest numbers were found to have stress incontinence [ 73.8% ( 484/656 ) ] followed by mixed [ 16.8% ( 110/656 ) ] and urge incontinence [ 9.5% ( 62/656 ) ] . in consulter group ,
total incontinence was 22.3% ( 458/2804 ) with highest number of stress incontinence [ 74.1% ( 458/618 ) ] followed by mixed incontinence [ 16.8% ( 458/618 ) ] and urge incontinence [ 9.1% ( 56/618 ) ] . in nonconsulters group , total incontinence was 19.3% ( 38/196 ) .
stress incontinence was commonest [ 68.4% ( 26/196 ) ] followed by same prevalence of urge and mixed incontinence 15.8% ( 6/196 ) of both .
it was seen that prevalence was low in women upto 30 years of age ( 7.5% and 11.6% in women < 20 years of age and between 21 and 30 years of age ) . in women above 30 years of age
, the prevalence ranged from 27.8% to 42.8% with maximum prevalence in the age group of 6170 years of age figure 1 .
there is marked difference in frequency of incontinence between women below 40 years of age ( median age of our study population ) and women above 40 years of age .
all types of urinary incontinence were found to be significantly higher among women above 40 years of age ( p < 0.001 ) .
however , in case of urge incontinence , prevalence was high only in grand multiparous women , while it was similar in nulliparous and women of low parity ( p = 0.244 and 1.35 ) the prevalence of all types of urinary incontinence was significantly higher in postmenopausal women and women who have had hysterectomy ( p < 0.05 ) [ table 2 ] .
the prevalence of urinary incontinence was 20.77% and 26.25% in women with body mass index less than or equal to 25 and more than 25 , showing a significant difference between the two ( p < 0.004 ) . among different types ,
stress and mixed but not urge incontinence were significantly associated with bmi > 25 [ table 3 ] . among chronic medical disorders ,
diabetes was not associated with increased prevalence of any type of incontinence ( p = 0.863 ) , while copd was associated with increased risk of having all types of incontinence ( p < 0.05 ) .
mode of vaginal delivery had a significant impact on prevalence of overall and stress incontinence , prevalence being higher in women having even one vaginal delivery .
there was no significant difference in incontinence for nulliparous and women having caesarean section only except for a slightly increased risk of mixed incontinence ( p = 0.041 ) .
the prevalence of overall and stress incontinence was significantly higher for persons with habit of tea intake ( p = 0.010 and 0.011 ) , while the prevalence of urge and mixed incontinence showed no significant association with tea intake .
multivariate analysis showed that in mixed and stress incontinence except for age and body mass index ( bmi ) , all the variables parity , personal habit , delivery type , history of hysterectomy , and asthma were significantly associated with complaints of incontinence table 4 . in urge incontinence apart from age and bmi , delivery type too did not show statistically significant association with complaints .
distribution of different types of incontinence age wise ( years ) distribution of urinary incontinence ( % ) correlation of various risk factors with incontinence on univariate analysis correlation of risk factors with different types of incontinence on univariate analysis correlation of various risk factors with incontinence multivariate analysis
in this cross - sectional study , urinary incontinence was self - reported and diagnosis was based on answers to leading questions about symptoms of urinary incontinence .
this study provides an opportunity to analyze the prevalence and determinants of different types of urinary incontinence separately in a large series of subjects using standard methods for recording symptoms .
the questionnaire directly filled by physician increases the reliability of diagnosis of various types and risk factors of incontinence . out of 3000 women , 656 women
reported urinary incontinence and prevalence was 21.87% . in various studies using[24 ] the same definition on similar population , prevalence was 2545% .
other studies using the same population but different definitions ( any leakage in previous 30 days ) reported a prevalence of 3537% . in our study , the prevalence of stress , mixed , and urge type was 16.13% , 3.67% , and 2.07% , respectively .
this was similar to most of the other studies ( 2 , 7 ) in which also stress incontinence was the commonest type .
only few studies found mixed incontinence to be commonest type . in our study , prevalence of urinary incontinence in young women ( 1830 years ) was only 9% which is strongly in contrast t 52% reported by nemir and middleton and 51% reported by wolin studied among college students .
significantly high prevalence ( 38.4% ) in women above 40 years is similar to most of the other studies where it ranges from 36 to 43% .
a definite trend of increasing prevalence in all types of urinary incontinence with increased parity suggests cumulative effect .
comparable results were obtained by swash who concluded that injury to the innervation of pelvic floor is worsened by successive deliveries .
pregnancy and child birth are regarded as key environmental determinants of urinary incontinence , and more than 60% of incontinent women associate its onset with pregnancy , child birth , or postpartum .
however , the impact of birth mode on incontinence and possible protective role of caesarean section have remained the subject of intense debate . in our study ,
prevalence of urinary incontinence is maximum among group with vaginal delivery ( 26.84% ) which was significantly higher than nulliparous women ( 9.42% ) and caesarean deliveries ( 8.59% ) .
this is in agreement to many studies that showed increased prevalence of urinary incontinence after vaginal deliveries .
parazzini also did not find increased risk of urge incontinence after vaginal delivery ( or 0.7 ) .
the most biologically plausible rationale for this association is surgical trauma caused when uterus and cervix are severed from pelvic floor supportive tissues at the time of hysterectomy .
hysterectomy could interfere with intricate urethral sphincter mechanism by damaging distal branches of pudendal nerves and inferior hypogastric plexus but it might also result in changes in bladder and urethral neck support . in our study ,
a significant association between hysterectomy and all types of incontinence was found ( p = 0.001 ) .
burgio et al and eva samuelsson found no significant association between hysterectomy and urinary incontinence . in a meta - analysis ,
there are studies showing association between coffee , alcohol , smoking , and incontinence . in this study ,
effect of tea and tobacco intake is studied which shows significant association with overall and stress incontinence .
norwegian eppincott study evaluated the effect of tea intake and concluded that tea drinkers were at slightly higher risk for all types of incontinence .
arya et al reported that high caffeine intake is related to detrusor instability , while burgio reported no effect of coffee on incontinence . in this study ,
smoking effects continence by damage to urethral sphincter mechanism by frequent coughing , decrease in collagen synthesis , and smoking - related vascular diseases .
with regard to medical history , role of type 2 diabetes is not completely understood . in this study ,
urinary incontinence is a very distressing problem . with the help of simple questionnaire , burden of disease can be estimated .
knowing about prevalence and risk factors of urinary incontinence is very important , so that necessary steps in its prevention and treatment can be taken . | background and objectives : urinary incontinence is a problem that creates both physical and psychological nuisance to a woman .
this problem needs to be studied in detail in indian population because of lack of precise data .
the objectives of this study were to study the prevalence and risk factors of urinary incontinence in indian women.materials and methods : this hospital - based cross - sectional study conducted from august 2005 to june 2007 included women attending gynecology opd ( consulters ) and hospital employees ( nonconsulters ) .
subjects who were incontinent were asked a standard set of questions .
incontinence was classified as urge , stress , or mixed based on symptoms .
a univariate followed by multivariate analysis was done to look for risk factors.results:of 3000 women enrolled , 21.8% ( 656/3000 ) women were incontinent .
there was no significant difference in incontinence rate between consulters and nonconsulters [ 618/2804 ( 22.1% ) vs. 38/196 ( 19.4% ) ; p value = 0.6 ) .
of the total women having incontinence , highest numbers were found to have stress incontinence [ 73.8% ( 484/656 ) ] followed by mixed [ 16.8% ( 110/656 ) ] and urge incontinence [ 9.5% ( 62/656 ) ] .
age more than 40 years ; multiparity ; postmenopausal status ; body mass index more than 25 ; history of diabetes and asthma ; and habit of taking tea , tobacco , pan , and betel are risk factors found to be associated with increased prevalence of urinary incontinence in univariate analysis . on multivariate analysis , age more than 40 years , multiparity , vaginal delivery , hysterectomy , menopause , tea and tobacco intake , and asthma were found to be significantly associated with overall incontinence .
stress incontinence was separately not associated with menopause .
urge incontinence was not associated with vaginal delivery.conclusion:urinary incontinence is a bothersome problem for women .
simple questionnaire can help to detect this problem and diagnose associated risk factors , so that necessary steps can be taken in its prevention and treatment . |
from january 2005 to july 2009 , 82 patients underwent dps and 78 patients underwent spdp for benign or low - grade malignant disease at first people s hospital affiliated to huzhou university medical college , huzhou , zhejiang province , china . spleen preservation was achieved in which the pancreas was dissected off the splenic vessels .
the medical records were reviewed to evaluate the clinical outcomes such as surgical factors ( operation time , estimated blood loss , transfusion ) , perioperative complications , postoperative hematological changes , and postoperative long - term outcomes ( endocrine / exocrine function , health condition , and recurrence ) .
the pancreatic stump is oversewn , and the omentum mobilized and sutured to the pancreatic stump .
an external close suction drain is placed near the pancreatic cut surface . in spdp , both the splenic artery and vein were preserved .
an external close suction drain was positioned in the splenic fossa close to the transected pancreas .
postoperative octreotide was administered subcutaneously ( dose 100 mg every 8 h ) for 2 weeks in both groups .
a pancreatic fistula was defined according to the guidelines of the international study group on pancreatic fistulas.5 postoperative bleeding was defined as proposed by the international study group on pancreatic surgery.6 three different grades of postpancreatectomy hemorrhage ( grades a , b , and c ) were defined according to the time of onset , site of bleeding , severity , and clinical impact .
mortality was defined as death within 30 days postoperatively , in or out of the hospital .
patients were assessed every month during the first postoperative year , and then every 3 months in the next few years after surgery .
the baseline assessment involved a medical history taking , life quality assessment , physical examination , hematological tests , chest radiography , and abdominal ultrasonography or computed tomography .
the diagnosis of recurrence was made on the basis of imaging and , if necessary , cytologic analysis or biopsy .
continuous variables are expressed as meansd , and categorical variables are shown as frequency ( percentage ) .
statistical differences were evaluated by the test , the student t test , and the paired t test .
clinical features of patients and indications for dps or spdp are shown in table 1 .
there were no significant differences in age , sex , preoperative diabetes mellitus , preoperative wbc count , platelet count , body mass index , tumor location , lesion size , and final diagnoses .
there were no significant differences in estimated blood loss , intraoperative transfusion , and operative time between the 2 groups .
. however , more perioperative complications occurred in the dps group than in the spdp group ( 34/82 vs. 20/78 , p=0.0344 ) .
consequently , postoperative hospital stay was significantly shorter in the spdp group than in the dps group ( 13.53.4 vs. 12.42.8 d , p=0.0273 ) .
patients in the dps group had more postoperative pancreatic fistulas of a higher grade ( p=0.0319 ) . furthermore , more frequent and various infectious complications occurred in the dps group , including intra - abdominal abscess , wound infection , and pneumonia ( p=0.0372 ) .
perioperative details and complications wbc counts on postoperative day ( pod ) 2 ( fig .
1 ) were significantly higher in the dps group than in the spdp group ( 14.23.3 vs. 10.22.8 , p=0.0000 ) , and this difference continued until postoperative month ( pom ) 1 .
1 ) in the spdp and dps groups remained low from pod 1 to pod 5 , and then started to increase thereafter .
serum hemoglobin on pod 3 was significantly higher in the spdp group than in the dps group ( 114.711.4 vs. 108.410.4 , p=0.0004 ) , and this difference continued until pom 6 .
1 ) in both groups were significantly decreased compared with the preoperative levels on pod 1 to 2 , increased to the maximum levels at 2 weeks after surgery , and decreased thereafter .
platelet counts on pod 5 were significantly higher in the dps group than in the spdp group ( 285.728.4 vs. 264.429.2 , p=0.000 ) , and this difference continued until pom 3 .
serum crp levels on pod 2 were significantly higher in the dps group than in the spdp group ( 174.514.2 vs. 166.714.7 , p=0.0008 ) , and this difference continued until pom 3 .
serum albumin levels did not differ significantly between the 2 groups at any postoperative time point .
a total of 160 patients [ follow - up rate 100% , median follow - up period 42 ( range , 24 to 76 ) months ] were contacted by telephone and all of them agreed to respond to the follow - up survey .
however , it was noteworthy that episodes of common cold or flu were apparently more frequent in the dps group ( p=0.047 ) ; there were 13 patients who had caught a cold > 5 times a year , as compared with only 5 patients in the spdp group .
there were significantly more patients in the dps group who felt fatigue ( p=0.0481 ) and poor health condition ( p=0.0371 ) .
regarding endocrine function , 10 and 2 patients had newly developed diabetes mellitus in the dps group and spdp group ( p=0.0193 ) among the patients with preoperative normoglycemia , respectively .
diabetes aggravated more frequently in the dps group than in the spdp group ( p=0.0361 ) .
recurrence occurred in 1 patient 5 years after undergoing dps because of intraductal papillary mucinous neoplasm .
clinical features of patients and indications for dps or spdp are shown in table 1 .
there were no significant differences in age , sex , preoperative diabetes mellitus , preoperative wbc count , platelet count , body mass index , tumor location , lesion size , and final diagnoses .
there were no significant differences in estimated blood loss , intraoperative transfusion , and operative time between the 2 groups .
. however , more perioperative complications occurred in the dps group than in the spdp group ( 34/82 vs. 20/78 , p=0.0344 ) .
consequently , postoperative hospital stay was significantly shorter in the spdp group than in the dps group ( 13.53.4 vs. 12.42.8 d , p=0.0273 ) .
patients in the dps group had more postoperative pancreatic fistulas of a higher grade ( p=0.0319 ) . furthermore , more frequent and various infectious complications occurred in the dps group , including intra - abdominal abscess , wound infection , and pneumonia ( p=0.0372 ) .
1 ) were significantly higher in the dps group than in the spdp group ( 14.23.3 vs. 10.22.8 , p=0.0000 ) , and this difference continued until postoperative month ( pom ) 1 .
1 ) in the spdp and dps groups remained low from pod 1 to pod 5 , and then started to increase thereafter .
serum hemoglobin on pod 3 was significantly higher in the spdp group than in the dps group ( 114.711.4 vs. 108.410.4 , p=0.0004 ) , and this difference continued until pom 6 .
1 ) in both groups were significantly decreased compared with the preoperative levels on pod 1 to 2 , increased to the maximum levels at 2 weeks after surgery , and decreased thereafter .
platelet counts on pod 5 were significantly higher in the dps group than in the spdp group ( 285.728.4 vs. 264.429.2 , p=0.000 ) , and this difference continued until pom 3 .
serum crp levels on pod 2 were significantly higher in the dps group than in the spdp group ( 174.514.2 vs. 166.714.7 , p=0.0008 ) , and this difference continued until pom 3 .
serum albumin levels did not differ significantly between the 2 groups at any postoperative time point .
a total of 160 patients [ follow - up rate 100% , median follow - up period 42 ( range , 24 to 76 ) months ] were contacted by telephone and all of them agreed to respond to the follow - up survey .
however , it was noteworthy that episodes of common cold or flu were apparently more frequent in the dps group ( p=0.047 ) ; there were 13 patients who had caught a cold > 5 times a year , as compared with only 5 patients in the spdp group .
there were significantly more patients in the dps group who felt fatigue ( p=0.0481 ) and poor health condition ( p=0.0371 ) .
regarding endocrine function , 10 and 2 patients had newly developed diabetes mellitus in the dps group and spdp group ( p=0.0193 ) among the patients with preoperative normoglycemia , respectively .
diabetes aggravated more frequently in the dps group than in the spdp group ( p=0.0361 ) .
recurrence occurred in 1 patient 5 years after undergoing dps because of intraductal papillary mucinous neoplasm .
splenectomy involved in other major abdominal organ resection was found to be responsible for increased postoperative morbidity , especially infectious complications .
white et al7 demonstrated that distal pancreatectomy with spleen preservation reduced perioperative infectious complications , severe complications , and length of hospital stay , suggesting the value of spleen preservation in distal pancreatectomy . in addition , opsi and increasing concern for the potential risk of malignancy after splenectomy have raised the necessity of spleen preservation.8 as the role of the spleen has gradually become recognized over the past several decades , many surgeons now try to preserve the spleen whenever performing distal pancreatectomy in benign or borderline malignant tumors of the distal pancreas .
however , despite the theoretical background of the spleen s role , clinical adverse events related to splenectomy seem to be very rare
. some surgeons may not agree with the value of the spleen in adult patients .
in addition , considering the technical demands of spdp as compared with conventional dps , some may argue against the efforts to preserve the adult spleen when performing distal pancreatectomy.4 however , according to our present results , there were no significant differences in estimated blood loss , intraoperative transfusion , operative time , and postoperative 30-day mortality between patients who underwent sdpd and dps .
in addition , spdp was demonstrated to yield better perioperative outcomes , with shorter hospital stays , lower grade complications , lower incidence of pancreatic fistula , and , most importantly , lower incidence of infection - related complications than dps .
even these perioperative results suggest that it is best to conserve the spleen whenever possible .
the most frequent time interval between splenectomy and opsi was 10 to 19 years , and their overall mortality reached approximately 50% .
this finding is very important to patients with a high chance of long - term survival , such as the current patient group.9 the frequency of common cold or flu in the dps group may indirectly suggest a lifetime chance of developing opsi . according to our results , patients who undergo dps
are thought to be vulnerable to respiratory tract infection and can develop critical infectious complications such as opsi .
several studies have compared the early perioperative hematological outcomes of spdp and dps.10,11 however , serial measurements of hematological parameters have not been carried out .
therefore , in the present study , we continuously investigated the platelet and wbc counts , hemoglobin level as an index of anemia , serum albumin as an index of nutrition , and serum crp as an index of inflammation in both groups . in this study ,
the increases in wbc count early after dps did not reflect the surgical stress level , but may have been a physiological reaction to splenectomy.12 the clinical significance of an elevated wbc count early after splenectomy is unclear , but it may be a risk factor for myocardial infarction.13 a significantly higher platelet count was observed from 5 days through 3 months after dps than after spdp . the significant increase in the platelet count after dps may have been because of loss of the spleen , which serves as a site of platelet sequestration . it is reported that thrombocytosis after splenectomy , injury , and coronary bypass increases the risk for thromboembolic complications.14 hemoglobin level decreased early after operation , and then started to recover after pod 5 .
recovery of the hemoglobin level was significantly greater in the spdp group than in the dps group .
this difference may have been because of the preservation of the spleen , which is a site of iron storage and splenic macrophages are able to efficiently reuse iron.15 the crp levels were significantly higher in the dps group than in the spdp group from pod 3 until pom 3 , possibly because of prolonged mild inflammation.16 additional advantages of spleen preservation were observed in the long - term follow - up study , with better results in terms of fatigue and general condition .
these problems , however , could act as factors that influence the quality of life ; thus , care must be taken during the follow - up period . in summary ,
distal pancreatectomy with or without splenectomy can be performed safely ; however , in this study , more frequent severe complications , prolonged hospital stays , and severe hematological abnormalities were noted in the dps group . in addition , this long - term follow - up study indirectly suggested vulnerability to respiratory infection and impaired quality of life after dps .
therefore , surgeons are advised to apply a spleen - preserving policy when performing distal pancreatectomy , even in adult patients .
this extra effort and responsibility on the part of the surgeon would have invaluable benefits for the patients . | goals : we designed this study to evaluate the efficacy of spleen salvage during distal pancreatectomy for patients with benign and borderline malignant tumors.background:despite the emphasis on its role , the spleen has commonly been removed in distal pancreatectomy.study:from january 2005 to july 2009 , 82 patients underwent distal pancreatectomy with splenectomy ( dps ) and 78 patients underwent spleen - preserving distal pancreatectomy ( spdp ) .
medical records were retrospectively reviewed.results:there were no significant differences in demographics , final diagnoses , estimated blood loss , intraoperative transfusion , and operative time between the 2 groups .
more perioperative complications occurred in the dps group than in the spdp group ( p=0.0344 ) .
consequently , postoperative hospital stay was significantly shorter in the spdp group than in the dps group ( p=0.0273 ) . in the follow - up survey , episodes of common cold or flu were apparently more frequent in the dps group ( p=0.047 ) .
more patients in the dps group felt fatigue ( p=0.0481 ) and poor health condition ( p=0.0371 ) .
less newly developed ( p=0.0193 ) and aggravated diabetes mellitus ( p=0.0361 ) were also observed in the spdp group .
platelet counts on postoperative day ( pod ) 5 , hemoglobin on pod 3 , wbc counts , and crp level on pod 2 were significantly higher in the dps group than in the spdp group and these differences continued to be significant for months after surgery.conclusions:in addition to frequent higher grade complications , prolonged hospital stays , and severe hematological abnormalities , dps seemed to result in poor health condition based on the follow - up survey .
even an effort to preserve an adult spleen in distal pancreatectomy is worthwhile . |
hutchinson gilford progeria syndrome ( hgps ; mim 176670 ) was first described in 1886 by jonathan hutchinson and by hastings gilford in 1897 . since then , just over 100 cases of hgps have been reported and currently , there are approximately 40 known cases worldwide .
significant morbidity and mortality result from accelerated atherosclerosis of the carotid and coronary arteries leading to premature death during the second decade of life .
a three - year - old boy presented with progressive loss of scalp hair , eyebrows , and eyelashes since six months of age along with stunted growth as a major complaint .
the child 's antenatal history was normal but was born to third - degree consanguineously married parents . on examination , he had a senile look with prominent eyes , sparse hair with patches of alopecia and visible veins over the scalp , beaked nose , and receded chin [ figure 1 ] . his voice was high pitched and growth was stunted as parameters were less than the third percentile .
teeth and genitals were normal and intelligence quotient ( iq ) was corresponding to the age .
hands were short and clawed with thickening and hardening of the skin over the knuckles with racquet nails .
there was mottled pigmentation and sclerodermatous changes over the trunk and lower limbs [ figure 2 ] .
lower limbs also had prominence of knees and slight valgus deformity [ figures 3 and 4 ] .
typical facies of progeria : senile look with prominent eyes , sparse hair , beaked nose , and receded chin mottled pigmentation and sclerodermatous changes over the trunk skin tightening and prominence of knees mid flexion and slight valgus deformity of lower limbs leading to a horse - riding stance
the serum lipid profile showed a decrease in high - density lipoproteins ( hdl ) .
x - ray of the chest showed a pyriform thorax , overcrowding of proximal ribs , and short clavicle with pointed lateral ends [ figure 5 ] .
x - ray of the skull showed diastasis of the sutures and prognathism [ figure 6 ] .
x - rays of hands and feet showed acro - osteolysis of phalanges and tarsals [ figure 7 ] .
x - ray of the chest showing a pyriform thorax , overcrowding of proximal ribs , and short clavicle with pointed lateral ends x - ray of the skull showing diastasis of the sutures and prognathism .
most cases of hgps occur due to de novo autosomal dominant mutation in the lmna gene , located on band 1q21.1 - 1q21.3
this leads to abnormal transcription of the nuclear lamina structural protein called prelamin a. normal farnesylation of prelamin a allows it to attach to the nuclear membrane .
failure to remove this farnesyl group , due to the mutation , permanently affixes the protein to the nuclear membrane [ table 1 ] .
this affects nuclear morphology and integrity , deoxyribonucleic acid ( dna ) repair , regulation of gene expression , and telomere stability .
ultimately , there is genomic instability , decreased cell proliferation , and premature cell senescence and death .
difference in prelamin a formation in normal and mutated lmna gene the infant is generally healthy at birth but there may be sclerodermatous skin changes involving the trunk and extremities in some cases .
hair growth decreases over the scalp and other parts of the body with areas of alopecia followed by cardiovascular involvement .
lipodystrophy involving the face leads to typical facies with senile look , glyphic nose , and
involvement of the lower limbs with valgus deformity and mid flexion leads to a horse riding stance .
there is diffuse osteopenia , acro - osteolysis of the phalanges and distal clavicles , but bone age is normal .
hgps is considered a segmental progeroid syndrome in the sense that it does not recapitulate all the characteristic phenomena of aging like increased tumor formation and cataract development .
hypertension develops , but unlike arteriosclerosis in the general population , in progeria , the only lipid abnormality is decreased hdl levels .
this syndrome should be distinguished from scleroderma , cockayne syndrome , rothmund thomson syndrome , werner syndrome , acrogeria , and anhidrotic ectodermal dysplasia . in our case ,
cockayne syndrome was ruled out because of lack of photosensitivity , facial erythema , and ocular defects , and normal iq .
thomson syndrome was ruled out by the absence of erythema , poikiloderma , and cataract .
acrogeria also manifests at birth but involves only extremities with no tendency to atheroma or decreased life expectancy .
there was an absence of conical teeth , hypotrichosis , and partial or complete anhidrosis , which ruled out hypohidrotic ectodermal dysplasia .
typical clinical features of the child were sufficient to make the diagnosis . decreased hdl levels and typical x - ray findings confirmed the diagnosis . | hutchinson gilford progeria syndrome is a rare genetic disorder characterized by premature aging involving the skin , bones , heart , and blood vessels .
we report a three - year - old boy with clinical manifestations characteristic of this syndrome .
he had a characteristic plucked - bird appearance , prominent eyes and scalp veins , senile look , loss of scalp hair , eyebrows , and eyelashes , stunted growth , and mottled pigmentation with sclerodermatous changes over the trunk and lower limbs .
radiological changes and decreased high - density lipoprotein ( hdl ) levels were also characteristic of the syndrome . this interesting case is reported for its rarity . |
chondroid syringomas ( cs ) , first described by hirsch and helwig in 1961 , is a rare , benign , skin appendageal tumor , the reported incidence of which is < 0.098% of all the primary cutaneous neoplasms .
being a counterpart of mixed tumor ( pleomorphic adenoma ) of salivary glands , it is also termed as
mixed tumor of the skin the malignant variant of cs is believed to be even rarer and has commonly been reported in the extremities and trunk and extremely rarely in the head and neck region .
our patient , to the best of our knowledge , is the first case of malignant cs of the pinna and the fourth to arise in the head and neck region .
a 41-year - old gentleman without any known comorbid illnesses was initially evaluated at an outside center for multiple swellings of the left neck of 4 months duration .
an fine needle aspiration cytology ( fnac ) from one of the swelling was suggestive of a poorly differentiated carcinoma and he was referred to our center for further evaluation .
clinical examination at our center revealed the multiple enlarged left cervical lymph nodes involving levels ii , iii , and iv of varying sizes , the largest measuring 2.5 cm 2.5 cm in the left level iia .
the thyroid gland was found to be minimally enlarged with multiple ill - defined nodules along both the lobes .
clinical examination further revealed a painless 3 cm 3 cm swelling in the upper part of the left helix ( of the left pinna ) which was firm , fixed to the skin , but was freely mobile over the underlying ear cartilage [ figure 1 ] .
when further probed , the patient gave a history of a long - standing swelling in the left pinna with a slight increase in size over a period of 4 months .
clinical photograph at presentation an ultrasound neck showed multiple nodules in both lobes of thyroid alongside multiple significant nodes in the left neck along levels ii , iii , and iv .
an ultrasound - guided fnac from the thyroid showed benign follicular cells with occasional inflammatory cells , but no atypical cells .
an fnac done from left level ii lymph node , however , was suggestive of carcinoma of glandular origin ( immunohistochemistry for thyroid transcription factor-1 was negative ) . a provisional diagnosis of an adenocarcinoma from an unknown primary with an incidental sebaceous cyst in the left pinna was made .
further evaluation with a positron emission tomography - computed tomography ( pet - ct ) showed avidity in the multiple cervical lymph nodes involving the left level iia ( standardized uptake value [ suv ] 3.8 ) , left level iii and left level iv ( suv 2.9 ) .
further , positron emission tomography avidity was also noted in the lobulated soft tissue lesion with necrosis arising from left pinna ( suv 2.9 ) and multiple hypo dense lesions in both lobes of thyroid ( suv 4.2 ) [ figures 2 and 3 ] .
( a - d ) axial computed tomography ( ct ) images , ( e - h ) the corresponding axial positron emission tomography - ct image showing uptake in the multiple cervical lymph nodes involving the left levels ii to iv ( a and b ) coronal positron emission tomography - computed tomography images , ( c and d ) coronal positron emission tomography ( pet ) images : showing uptake in the multiple cervical lymph nodes involving the left level iia ( standardized uptake value [ suv ] 3.8 ) , left level iii and left level iv ( suv 2.9 ) .
further , pet avidity was also noted in the lobulated soft tissue lesion with necrosis arising from left pinna ( suv 2.9 ) and multiple hypo dense lesions in both lobes of thyroid ( suv 4.2 ) a repeat fnac from the thyroid showed no atypical cells .
however , the fnac from the left ear helix swelling interestingly showed few clusters of atypical epithelial cells suggestive of epithelial malignancy .
a preoperative diagnosis of a possibly skin adnexal tumor with cervical lymph node metastasis was made .
the patient underwent a wide excision of ear helix tumor and left radical neck dissection .
the defect in the pinna was bridged by a local advancement flap [ figure 4 ] .
his final histopathology was suggestive of a malignant cs of the left pinna resected with clear margins and metastasis in 48/53 left cervical lymph nodes [ figure 5 ] .
the patient after a multi - disciplinary board discussion was considered for adjuvant radiotherapy to the tumor bed and neck .
postoperative clinical photograph of the patient following the wide excision of left ear helix tumor and left radical neck dissection .
the defect on the pinna was bridged by a local advancement flap ( a and b ) section shows a malignant neoplasm composed of lobules of cells arranged in a glandular pattern forming cystic lumina admixed with lobules composed of solid sheets of plasmacytoid cells with eosnophilic to clear cytoplasm , numerous tumor giant cells , comedonecrosis and increased mitosis ( h and e 20 ) , ( c ) shows chondroid syringoma with frank carcinomatous areas , ( d ) chondroid syringoma showing metastasis in the cervical lymph nodes
chondroid syringomas are rare skin tumors which are known to arise from the eccrine sweat glands .
they belong to the family of myoepithelial tumors , which consists of morphologically similar tumors that includes , pleomorphic adenoma of the salivary gland , cs of skin and mixed tumor of somatic soft tissue and bone .
they usually present as a painless , solid , subcutaneous or dermal nodule with a normal margin .
the mean age of the patients at the time of diagnosis was 48.3 years ( range 1384 years ) .
they can be confused clinically with various other skin lesions including dermoid or sebaceous cysts and neurofibromas .
malignant cs are extraordinarily rare tumors which may originate de novo or can rarely develop in a cs . unlike its benign counterpart , the malignant cs occurs predominantly in females ( 3:2 ) , has no definite age predilection and has been reported to occur more commonly in the extremities .
malignant lesions are usually > 3 cm ; however benign tumors measuring 10 cm have also been reported .
a few reports have described the magnetic resonance imaging findings of benign and malignant cs , which are in fact nonspecific .
there are hardly any reports of the use of pet - ct as a staging modality in the management of malignant cs .
the histological features suggestive of malignancy in a cs include cytologic atypia , infiltrative margins , satellite nodules , necrosis , and involvement of the deeper structures .
malignant tumors that may bear similar characteristics with malignant css include well - differentiated and myxoid liposarcomas , extraskeletal myxoid chondrosarcoma , myxofibrosarcoma , and malignant peripheral nerve sheath tumors .
the management of cs is predominantly surgical and consists of complete excision of the tumor . for malignant cs
malignant cs tend to behave in an unpredictable manner ; deaths have been reported to occur as early as 9 weeks following surgery ; on the other hand , the longest reported survivor has been 12 years .
of the reported cases , nearly half of the patients have had local recurrences and 39% had nodal metastases .
distant metastases were reported in about 36% of the cases , the most common site was the lung , followed by bone and brain .
there are no uniform guidelines with regards to the management of malignant cs , especially in the metastatic setting .
a pet - ct may be a useful tool in staging and in the follow - up of patients with malignant cs considering its high propensity for nodal and distant metastasis .
targeted therapies with pi3k / akt / mtor pathway inhibitors , currently in early clinical trials , are being explored as potential treatment options .
malignant css , being biologically aggressive tumors , presents with many diagnostic and management challenges .
a pet - ct scan may be a useful modality in staging as was seen in our patient .
achieving a negative surgical margin using wide excision technique remains the mainstay of management of malignant css ; these patients need to be further monitored closely due to its heightened metastatic potential . | chondroid syringoma ( cs ) represents the cutaneous counterpart of mixed tumor ( pleomorphic adenoma ) of salivary glands .
the malignant counterpart of cs , termed as
malignant cs is a malignant eccrine neoplasm which lacks distinctive clinical features , often delaying initial diagnosis . unlike its benign counterpart which often localizes in the head and neck region , malignant cs
most often encountered in the trunk and the extremities .
we report a rare case of an aggressive malignant cs of the left pinna with cervical lymph node metastasis .
our patient , to the best of our knowledge , possibly is the first case of malignant cs of the pinna and the fourth to arise in the head and neck region . the diagnostic challenges with an added emphasis on the role of positron emission tomography - computed tomography in aiding the management of this rare tumor are discussed . |
a 58-year - old man suddenly developed a numb sensation in his trunk and leg on the left side .
he had no history of hypertension , diabetes mellitus , cardiac problem ( including arrhythmia and coronary heart disease ) , or previous stroke , and he was a nonsmoker .
a neurological examination performed the day after presentation revealed that he was alert and oriented , and did not have dysarthria or dysphagia .
both pupils were of equal size and reactive , without nystagmus , ophthalmoplegia , or horner 's syndrome .
muscle strength was intact in the extremities . a sensory examination including a pinprick test and a cold sensory test revealed that pain and temperature sensations were decreased by about 80% in the left trunk ( below the t4 dermatome ) and leg .
however , he did not report a definite difference in the sensation between the trunk and leg on the left side .
cerebellar function , as assessed by finger - to - nose , tandem gait , and romberg 's sign test , also was preserved .
he complained of an uncomfortable sensation in his left leg and foot on a hopping test , but showed no falling tendency or gait disturbance .
diffuse- and t2-weighted magnetic resonance imaging ( mri ) of the brain , performed on the second hospital day , showed a small lesion with a high signal intensity in the right lower medulla oblongata consistent with acute infarction ( fig .
thoracicspine mri and somatosensory evoked potential ( sep ) were performed to exclude spine lesions , and revealed no abnormal findings .
results from laboratory studies , including complete blood cell and platelet counts , erythrocyte sedimentation rate , blood electrolytes , chemistry , liver enzymes , cholesterol , triglycerides , and homocysteine , and the prothrombin and partial thromboplastin time were all normal .
chest x - ray , echocardiogram , and electrocardiography also were all normal . the patient was treated with antiplatelet agents , and showed a gradual improvement of sensory deficits to about 60% of normal sensation without fluctuation of symptoms .
the clinical features of lmi can have diverse neurological manifestations due to the anatomical characteristics of the medulla.4 according to previous reports , ataxia was the most common neurological symptom in lmi , and was more common in patients with lesions located in the laterocaudal part of the medulla.5 contralateral hypalgesia is the next most frequent neurological symptom of lmi.4 the most common pattern of sensory abnormality in lmi is loss of pain and heat sensations on the ipsilateral side of the face and on the lower part of the body on the contralateral side , which is associated with other common manifestations such as vertigo , unsteadiness , horner 's syndrome , and dysphagia.3,6 however , pure sensory deficits as an isolated symptom are not a feature of lmi .
moreover , pure sensory deficits in a dermatomal distribution as in the present patient have been not reported previously . in our case ,
pure sensory deficit with a t4 sensory level occurred as a single and isolated manifestation of lmi without any of the other common neurological symptoms .
we attributed this to the lesion being restricted to the right mediolateral aspect of the medulla , posterior to the inferior olivary nucleus .
moreover , sensory deficit below the t4 level on the contralateral side of the body in our patient was due to the somatotopical organization of the spinothalamic tract , because the sacral afferent fibers are located in the lateral medullary part and the cervical afferent fibers ascend more medially.6 the lesion did not extend sufficiently far to the posterolateral medulla to affect the ipsilateral descending tract and nucleus of the trigeminal nerve , thus sparing sensations in the ipsilateral face .
the crossed ventral trigeminothalamic tract courses to the medial part of the spinothalamic tract and carries pain and heat sensations from the contralateral side of the face .
thus , if the lesion extends more medially to involve ipsilateral cervical sensory fibers as well as the contralateral trigeminothalamic tract , this will lead to ipsilateral sensory deficit of the entire body without dermatomal representation or contralateral facial hypesthesia .
however , if the lesion extends more posterolaterally to involve the ipsilateral spinocerebellar tract , this will lead to vertigo and ipsilateral ataxia .
numerous reports have provided evidence that restricted acral sensory deficits frequently occur after small strokes in the thalamic and cortical areas .
for example , fisher stated that isolated paresthesia of the face , arms , and legs suggests thalamic involvement,7 and kim also observed that dominant sensory involvement of the upper lip , thumbs , and index fingers occurred with thalamic and thalamocortical infarction.8 therefore , the somatotopic topography of the ventralis posterior nucleus of the thalamus is relatively well known .
reported a patient with vibration and position sensory defects below the l5 sensory level caused by medial medullary infarction,9 and phan and wijdicks described a patient with pain and temperature sensory losses below the t9 sensory level associated with disequilibrium due to lmi following vertebral artery dissection.10 the present patient represents a rare case of lmi presenting with loss of pain and temperature sensations below the level of the t4 sensory dermatome as a unique neurological deficit .
the observations reported here will help to improve our understanding of the somatotopic topography of the brainstem , especially of the medulla . | in rare cases restricted sensory deficits along the somatotopic topography of the spinothalamic tract can develop from a lateral medullary infarction .
to our knowledge , isolated dermatomal sensory deficit as a single manifestation of a lateral medullary infarction has not been reported previously .
a 58-year - old man presenting with sudden left - sided paresthesia complained of sensory deficit of pain and temperature below the left t4 sensory level without other neurologic deficits .
diffuse- and t2-weighted magnetic resonance imaging ( mri ) of the brain showed high signal intensities in the right lower medulla oblongata , whereas thoracic - spine mri and somatosensory evoked potentials produced normal findings . |
most commonly , contractures arise where adequate burn care and delivery have not occurred and scar management has not been instigated in a vigorous manner . repair by regeneration can no longer occur when the depth of injury extends beneath the reticular dermis , and healing by secondary intention.1 the resultant wound contraction can lead to contractures over flexor surfaces and its surroundings .
for example , limitation of opening jaws may cause difficulties in accessing the dentitions and tissues of the oral cavity , and in using full size of removable denture for the patients .
telescopic implant - supported removable partial prosthesis with milled abutments has been used for the patient with burn contracture to provide enough retention and stability for the prosthesis .
a 60-year old woman was referred from the plastic surgery department to the department of prosthodontics at yonsei university health system .
she had a chief complaint of restoring her oral function and esthetics after series of plastic skin graft procedure done . during the extra oral examination
it was noted that the elasticity of muscle and skin tissue around oral angular area was lost due to scars from burns and tissue grafting , which resulted in limited maximum mouth opening of 20 mm .
therefore , proper prosthodontic treatment was impossible on the right quadrants of the mouth ( fig .
the intraoral examination showed that all of maxillary teeth were missing except tooth number # 25 and splinted gold crowns on # 34 and # 35 , whereas fixed partial denture on # 33 to # 43 were present on the mandible . in order to restore the patient 's masticatory function , prosthodontic treatment plan of using 4 implants on the left quadrants
each of two implants were placed on upper and lower posterior left jaws , however no implant on anterior ridge were possible due to severe atrophy of the maxilla .
anterior cantilever type removable partial denture was planned to meet patient 's esthetic demand , which consists of a telescopic crown abutment on # 25 and two implant supported abutments on area of # 26 and # 27 in the maxillary area ( fig .
2 ) . on the mandible , implant - supported fixed partial denture on area of # 36 and # 37 was planned .
the implants ( strauman basel , switzerland ) ( 4.810 mm ) were placed on predetermined area accompanied with sinus lift ridge augmentation procedure and proper follow up was performed during the 6 month healing period of time .
customized abutments were fabricated on implants and designed in the predetermined angle paralleling to the prepared tooth of # 25 ( fig .
3 ) . removable partial denture was inserted to verify phonetics , esthetics and function .
key and keyway rigid attachment was used for retention and ledge type rest was used for support ( fig .
no complications have occurred in 5 years since the insertion of the prostheses ( fig .
removable type of prosthesis was selected as treatment option after considering the factors of oral hygiene maintenance and lip support of patient to improve esthetics . because there was only one natural tooth in the maxilla , we , therefore , had to improve the unfavorable removable partial denture using implants.2 due to the lack of anterior ridge , the implant option on anterior ridge was deemed unavailable , and natural tooth was splinted with implant to support anterior cantilevered prosthesis .
combining implants with natural teeth is controversial because of the variations in movement during function.3 a lot of complications regarding implant and tooth - supported prosthesis may arise ; including fracture of the prosthetic components , intrusion of the natural tooth , marginal bone loss , and loss of osseointegration,4 but survival rates of implant and tooth - supported fixed prostheses are comparable to implant - supported fixed prostheses.5 there was no prosthetic complication in implant - and tooth - supported fixed prosthesis in this case . in this case ,
forces in the cantilevered area were transmitted to the abutments , causing tilting and rotational movements,6 but cantilevered prostheses are preferable when reduced stress is inherent.6,7 the prosthesis in this patient is expected to have a good prognosis since it is designed with hypoocclusion in anterior areas . | the scars and contracture around the oral - facial region may cause difficulty in prosthodontic treatment to restore esthetics and function for the patients , who suffered severe burns .
this article presents a technique that uses a fixed partial denture prepared with a conventional milling technique and an attachment to support anterior cantilever removable partial denture , thereby providing a more esthetically acceptable and functional result . |
functional hallucinations are an unusual form of perceptual disorder , in which hallucinations are triggered by a stimulus in the same modality , and co - occur with it .
for example , a patient may report hearing voices criticizing him every time he hears the sound of a rotating fan , and which stop when the fan is not running .
their exact significance is unknown , but they have been reported in schizophrenia and other functional psychotic disorders .
the treatment of positive symptoms of schizophrenia , including hallucinations , generally involves the use of antipsychotics .
the following is the report of a patient diagnosed with schizophrenia , with persistent functional hallucinosis , who responded to the addition of sodium valproate .
a single man , aged 30 , employed in a factory , presented to our outpatient department , in 2007 , with two years continuous illness , characterized by persistent auditory hallucinations , secondary delusions of reference , social withdrawal , and impaired occupational functioning .
he also reported obsessive doubts about routine activities , such as closing doors or taps , and a compulsion to check whether he had done these properly , despite knowing that this was unnecessary .
he was diagnosed to have paranoid schizophrenia and obsessive - compulsive disorder , and was treated with risperidone ( titrated up to 8 mg / day ) and fluoxetine ( titrated up to 80 mg / day ) . on the above - mentioned medications , he improved significantly , and was able to return to his job .
his job involved frequent contact with machinery and motors . whenever he heard these machines running
he found these distressing , and this led him to frequently avoid his work or leave it incomplete .
he did not hear these voices at any other time , and did not report any recurrence of his other symptoms .
his body weight was 62 kg . due to financial difficulties ( the patient was receiving the above medications free of cost from the hospital ) and his overall good response to risperidone
therefore , he was given a trial of adjunctive sodium valproate , which was freely available in the hospital and had some evidence of efficacy in reducing positive symptoms , as an adjunct to antipsychotics .
after obtaining the patient 's consent , sodium valproate was initiated at a dose of 600 mg / day , and gradually increased by 200 mg every week based on his response and adverse effects . at 1000 mg
/ day of sodium valproate , the patient reported a significant reduction in his hallucinations , and he felt that he could carry out most of his work .
hence , valproate was further increased at the same rate , up to 1800 mg / day . at this dose ,
the patient reported feeling near - normal , and was in line for a promotion at his workplace .
however , he developed significant postural tremors , which interfered with his ability to work , and valproate was reduced to 1700 mg / day . at this dose , he reported that the voices had decreased by 75% , and he scored between 2 and 3 ( mild symptoms ) on item p3 ( hallucinations ) of the positive and negative symptom scale for schizophrenia .
he has remained on valproate 1700 mg / day , along with risperidone 8 mg / day and fluoxetine 80 mg / day , for the past three months , and has remained stable .
his functional hallucinations still occur from time to time at work , but he is less bothered by them and does not experience any impairment .
the management of patients with schizophrenia , who have a single persistent symptom , is a challenging situation .
evidence - based treatments , such as changes in medication or cognitive - behavioral therapy , may not always be feasible . in this patient , time and economic constraints made it unlikely that the patient would comply with either .
hence , an alternative that would be safe , affordable , and with some evidence of effectiveness was required . on account of the rarity of functional hallucinations
however , a single case report suggests that carbamazepine may be helpful . in psychiatry ,
a cochrane review suggests that it may be useful in reducing aggression and tardive dyskinesia , but has little effect on other symptoms .
however , one trial has suggested that adjunctive divalproex reduces positive symptoms , and a case series found the addition of valproic acid useful in difficult - to - treat schizophrenia patients .
the effect of adjunctive valproate in schizophrenia is probably not due to the elevation of risperidone levels .
valproate acts primarily through gamma - amino butyric acid ( gaba)-ergic mechanisms , which may modulate the actions of dopamine . alternately , it may act through an epigenetic mechanism involving the demethylation of relevant sections of the gaba - related genes .
finally , given the paroxysmal , event - triggered nature of the patient 's hallucinations , it is possible that valproate 's ability to block sodium channels in a use - dependent fashion , may have contributed to symptom amelioration , as carbamazepine did in the earlier case .
although it can not be recommended in all patients , this case suggests that valproate may be beneficial in selected cases , particularly as an add - on to antipsychotics . | functional hallucinations are a rare phenomenon , wherein hallucinations are triggered by a stimulus in the same modality , and co - occur with it .
although hallucinations in schizophrenia are normally treated using antipsychotics , not all patients respond to them .
the following is the report of a patient with paranoid schizophrenia who experienced persistent functional hallucinations , triggered by the sound of machines in his factory , in the absence of other psychotic symptoms .
these occurred despite adequate doses of risperidone , which had controlled his other symptoms .
the addition of sodium valproate , titrated up to 1700 mg / day based on response and tolerability , resulted in a marked improvement in this phenomenon and enabled him to return to work .
the implications and possible mechanisms of the patient 's response are discussed . |
with the incidence of obesity on the rise , an increasing number of patients are being frequently diagnosed with complications secondary to their high body mass index .
diabetes mellitus ( dm ) , hyperlipidemia , and coronary artery disease are a few of the more common diseases that seem to affect such individuals .
although several studies have been conducted to evaluate the safety profiles and interactions among the drug groups used to treat and manage these illnesses , unusual side effects may still arise in some patients.15 we aim to create awareness regarding one of the frequently used combinations of drugs , namely , sitagliptin and atorvastatin , the use of which resulted in rhabdomyolysis of the skeletal muscle in a patient .
although an isolated case , we propose and encourage further clinical trials in this area .
a 60-year - old female with past medical history significant for hypertension , dm , coronary artery disease , and hyperlipidemia presented to the emergency room with the chief complaint of chest pain .
she also reported generalized weakness , myalgias , subjective fever , and chills progressively worsening over the past 7 days .
her physical examination showed stable vital signs and was otherwise unremarkable except for trace peripheral edema .
the university of florida does not require irb approval or written informed consent for any case report with 3 or fewer patients as it is not a clinical study .
fearing a coronary event , she was given a dose of sublingual nitroglycerine and aspirin .
laboratory workup was significant for elevated creatinine phosphokinase ( cpk ) of 13,456 u / l ( reference range : 30170
u / l ) , normal troponin - t , normal complete blood count , and basic metabolic panel except elevated creatinine of 1.20 mg / dl ( reference range : 0.400.90 mg / dl ) .
cpk levels evaluated in 2012 on this patient while on statins were unremarkable ( 191 u / l , 165 u / l , and 197 u / l , with reference range of 30170
she was admitted to the hospital due to concern for acute coronary event , rhabdomyolysis , acute renal insufficiency , and possible acute viral infection causing her symptoms .
her workup during hospital stay showed three normal serial troponin - t tests , and myocardial perfusion test revealed no abnormality .
there was no history of recent trauma , crush injury , prolonged immobilization , recent surgery , seizures , drug abuse , or alcoholism .
her family history was negative for any kind of myopathy or other hereditary or genetic causes that could explain the elevated cpk value .
her laboratory workup , including thyroid function tests , was unremarkable and failed to explain this episode of rhabdomyolysis .
she had been on a stable dose of atorvastatin ( 40 mg ) for several years for hyperlipidemia and reported no myalgias , arthralgias , or abnormal cpk levels .
review of her medication list further revealed that she was started on sitagliptin ( januvia 100 mg ) almost a week before this presentation .
sitagliptin and atorvastatin were stopped ; her subsequent cpk value showed a decreasing trend and was recorded at 1,220 u / l on the day of discharge . the patient s muscle aches and chest pain had reduced considerably following the discontinuation of these medications
rhabdomyolysis is potentially a serious clinical condition that involves breakdown of muscle tissue , releasing myoglobin into the blood .
it can be caused by injuries to the skeletal muscles , which include trauma or crush injuries , severe exertion , dehydration , genetic muscle diseases , elevated body temperature , muscle tissue ischemia , electrolyte imbalance , and seizures , and can sometimes result from drug interactions .
a few signs and symptoms of rhabdomyolysis include body aches , generalized weakness , myalgia , fever , and sometimes hematuria .
atorvastatin belongs to the family of inhibitors of 3-hydroxy-3-methylglutaryl coenzyme a ( hmg - coa ) reductase , frequently known as statins , responsible for the conversion of hmg - coa to mevalonate , preventing the cholesterol synthesis pathway .
it is metabolized to its active metabolites , ortho- and para - hydroxylated forms , which are responsible for a majority of reactions .
atorvastatin is a substrate for hepatic cytochrome p450 ( cyp ) 3a4 , as well as p - glycoprotein and the transporter organic anion - transporting polypeptide 1b1 ( oatp1b1).68 this in turn tends to cause significant drug interactions with other cyp3a4 inhibitors , which may result in potential complications such as myopathies .
sitagliptin belongs to a newer class of agents known as dipeptidyl peptidase 4 ( dpp - iv ) inhibitors approved in 2006 by the us food and drug administration ( fda ) for the treatment of type 2 dm .
dpp - iv inhibitors slow down the inactivation of incretin hormones ( glucagon - like peptide-1 [ glp-1 ] and glucose - dependent insulinotropic polypeptide [ gip ] ) .
these hormones control blood glucose by increasing synthesis and release of insulin from pancreatic cells in response to a meal .
glp-1 also reduces hepatic gluconeogenesis by inhibiting the pancreatic cells.9 sitagliptin is primarily excreted in the urine as the unchanged drug by renal tubular secretion . about 16% of the drug
is excreted as its metabolites and primarily metabolized by cyp3a4 , cyp2c8 , and p - glycoprotein .
sitagliptin is not an inhibitor of cyp isozymes 3a4 , 2c8 , 2c9 , 2d6 , 1a2 , 2c19 , or 2b6 .
it is neither an inducer of cyp3a4 nor does it inhibit p - glycoprotein - mediated transport.10 a study by wilke et al11 showed that a nonsynonymous coding single - nucleotide polymorphism rs4149056 in slco1b1 significantly increased the exposure to simvastatin and the risk of muscle toxicity .
oatp1b1 , encoded by slco1b1 , facilitates the hepatic uptake of several endogenous compounds and statins .
changes in the activity of this transporter can increase the severity of statin - related muscle damage .
genetic variability in slco1b1 also alters plasma concentration of statins , although the overall pharmacokinetic profile of simvastatin appears to be altered more than that of any other drug in the class.12,13 pasanen et al14 demonstrated that homozygous carriers of the c allele at rs4149056 had a greater exposure to the active simvastatin acid than subjects homozygous for the ancestral t allele .
the frequency of mylagias with atorvastatin was 2.7%8.4% vs 3.1% in patients receiving placebo and is one of the common reported skeletal muscle side effects seen with the use of atorvastatin ( lipitor).8 in contrast , a study by graham et al9 in 2004 reported an average incidence of 0.44 in 10,000 patients ( who developed rhabdomyolysis ) being treated with atorvastatin , simvastatin , or pravastatin , with a 95% confidence interval of 0.200.84 .
these patients had been taking lipid - lowering agents alone or in combination.9 the fda reported a total of 601 cases of statin - associated rhabdomyolysis from november 1997 up till march 2000.15 the total case percentages associated with each statin were as follows : fluvastatin at 2% , lovastatin at 7% , pravastatin at 12% , atorvastatin at 12% , cerivastatin at 32% , and simvastatin at 36% . in a similar study by thompson et al,16
an expanded search was carried out to ensure compatibility with prior searches and 612 cases were identified for the same given period .
the incidence of fatal rhabdomyolysis through may in 2001 had been estimated using information from the databases obtained from the fda and national prescription audit plus ( ims health , fairfield , ct , usa ) and found to be at only 0.15 deaths per one million prescriptions.17 the estimated incidences per one million prescriptions for various statins were as follows : cerivastatin at 3.16 , lovastatin at 0.19 , simvastatin at 0.12 , pravastatin and atorvastatin at 0.04 , and fluvastatin at zero.17 diltiazem is considered a weak inhibitor of the cyp3a4 isoenzyme and although our patient had been taking diltiazem ( 180 mg daily ) along with atorvastatin for several months , it would be an unlikely cause for this acute rhabdomyolysis episode .
the patient developed rhabdomyolysis within a few days after sitagliptin was added to her continuing medical therapy , which included atorvastatin .
she did not have any other known etiologies for developing rhabdomyolysis , leading to the conclusion that the drug interaction between atorvastatin and sitagliptin caused toxicity and rhabdomyolysis .
medical literature review showed very limited case reports of potential interaction of sitagliptin with statins causing rhabdomyolysis.5,18 although sitagliptin has been reported to cause myalgias or arthralgias , it has not been reported to cause rhabdomyolysis on its own.5,1819
several drug interactions have been reported with statins in the past . to our knowledge , however , only one case has been reported on the interaction of sitagliptin with statins causing rhabdomyolysis , making this case an unusual presentation .
a medication review should thoroughly be done in case of myalgias in the absence of any medical or traumatic event likely to cause muscle damage . | rhabdomyolysis is a serious medical condition in which the skeletal muscle tissue gets damaged and breaks down at rapid rates , potentially leading to death if not managed early on .
rhabdomyolysis in adults has several etiologies such as crush injuries , prolonged immobilization , strenuous exercise , hormonal or metabolic causes , infections , and drug drug interactions .
we present a case report of the interaction of two drugs that are used commonly in the general population .
we here discuss a case of a 60-year - old female who presented to the hospital with complaints of generalized weakness , muscle aches , and atypical chest pain for a week after her primary care physician started her on sitagliptin while she was already on atorvastatin .
after review of literature , this is the second known case of such an interaction causing acute breakdown of skeletal musculature . |
skin and soft tissue infections caused by non - tuberculous mycobacteria have been increasingly described as a complication associated with many procedures , including liposuction , illicit soft tissue augmentation , acupuncture , and contamination from medical instruments during surgery [ 1 , 2 , 3 , 4 , 5 ] .
mycobacterium abscessus is a rapid - growing atypical mycobacterium that has been reported to cause a variety of cutaneous infections .
herein , we report a case of cutaneous m. abscessus infection associated with mesotherapy injection .
a previously healthy 44-year - old woman presented with a 3-week history of tender erythematous nodules on her face .
the lesions had developed 2 weeks after mesotherapy injection for facial rejuvenation , using an unknown substance administered by an uncertified aesthetician .
physical examination revealed multiple , discrete , tender erythematous nodules and plaques with minimal serosanguinous discharge on both cheeks ( fig . 1 ) and on the forehead ( fig .
a skin biopsy specimen obtained from a nodule on the right cheek revealed dense inflammation predominantly consisting of neutrophils , histiocytes and multinucleated giant cells in the superficial and deep dermis ( fig .
3 ) . gram staining , fungal and acid - fast bacilli stains were negative .
tissue culture was positive for m. abscessus , sensitive to clarithromycin , ciprofloxacin , doxycycline , cefoxitin , and amikacin .
the patient was treated with a combination of clarithromycin 500 mg twice daily , doxycycline 100 mg twice daily , and ciprofloxacin 500 mg twice daily according to the bacterial sensitivity testing .
the patient completed 6 months of treatment , which resulted in complete resolution of the lesions with minimal atrophic hyperpigmented scars .
mesotherapy was first introduced in france in 1952 , consisting of an injection of highly diluted drugs and different substances into the dermis and subcutaneous tissue .
this technique was originally developed to treat localized pain , vascular and lymphatic disorders , but its use in aesthetic medicine has increased in recent years .
m. abscessus belongs to the group of rapidly growing non - tuberculous mycobacteria which is characterized by a rapid growth rate ( within 7 days ) on the culture .
the organism is ubiquitously present in soil , decaying vegetation , and water ( e.g. , natural water , sewage water , drinking water tanks , and tap water ) .
m. abscessus causes a wide range of clinical diseases including skin and soft - tissue infection , keratitis , osteomyelitis , pulmonary infection , and disseminated infection . in skin and soft - tissue infection , it usually follows penetrating trauma and typically occurs in immunocompetent individuals .
there are several reports of outbreaks of m. abscessus infections caused by non - sterile techniques or contaminated materials , following surgery , liposuction , foreign body implantation , mesotherapy , acupuncture , and soft tissue augmentation [ 1 , 2 , 3 , 4 , 5 ] . the clinical presentations of cutaneous m. abscessus infection ranges from asymptomatic to tender erythematous violaceous nodules and plaques , cellulitis , abscesses , ulcer , and draining sinus with serosanguinous discharge .
approximately 1020% of localized cutaneous m. abscessus infections in immunocompetent patients resolve spontaneously without treatment in an average of 8 months .
currently , there is no standard guideline for the treatment of cutaneous m. abscessus infection .
multiple modalities including surgery , draining of abscesses , removal of necrotic tissue , foreign body removal , and an extended course of antibiotics are recommended .
however , the in vivo efficacy against the mycobacteria is not completely reflected by in vitro sensitivity alone , but also depends on the function of local and general host defenses against the infection .
m. abscessus is usually susceptible to clarithromycin , amikacin , linezolid , tigecycline and variably susceptible to cefoxitin and imipenem ( table 1 ) .
monotherapy is not recommended in treating m. abscessus infection because of the potential for emergence of antibiotic resistance , as has been reported with other mycobacteria , such as mycobacterium chelonae . in conclusion , we report a case of cutaneous m. abscessus infection associated with mesotherapy .
this case emphasizes the importance of adequate sterile measures in all medical procedures and stresses the need to suspect the possibility of an atypical mycobacterium infection in patients who develop late - onset skin and soft tissue infection after cutaneous injury , injections , and surgical interventions , particularly if they do not respond to conventional antibiotic treatment .
| non - tuberculous mycobacterial skin infections have an increasing incidence . in immunocompetent patients ,
they usually follow local trauma .
we present a case of cutaneous mycobacterium abscessus infection following mesotherapy .
the lesions were successfully treated with a combination of clarithromycin , ciprofloxacin , and doxycycline .
atypical mycobacterial infection should be suspected in patients who develop late - onset skin and soft tissue infection after cutaneous injury , injection , and surgical intervention , particularly if they do not respond to conventional antibiotic treatment . |
in experimental and even clinical scenarios of af extracellular fibrosis and inflammation as well as downregulation of several ion channels and gap junctions , nexus or macula communicans have been documented in atrial tissue .
both af and cardiac heart failure ( chf ) are associated with excess amount of reactive oxygen species ( ros ) .
these can cause trigger activity type arrhythmias ( early after depolarizations ( eads ) and delayed after depolarizations ( dads ) ) , reentry and potential therapeutic targets . due to
triggered activity , arrhythmias are often due to problems in the ion channels in the heart muscle cells .
they can also occur as a side effect of certain anti - arrhythmic drugs such as digitalis .
excess amount of ros alters multiple cardiac ion currents : activation of camkii , c - src , and pkc may mediate several important effects of ros on ion currents resulting in arrhythmia .
ros produces na current reduction ( via pkc and c - src , also via abnormal splicing mrna ) and reduction conduction velocity , abnormal splicing , activation of camkii , c - src , and pkc are among emerging new antiarrhythmic therapeutic targets .
ros may stimulate the inward l - type ca current ( direct or via camkii activation facilitating after depolarization , which can facilitate eads ) with abnormal depolarization during phase 2 or phase 3 .
ros is also responsible by inhibition of k+ channels ito , ikr , iks and katp with consequent abnormal repolarization .
ros causes adversely affected splicing of mrna of cardiac na channels resulting in abnormal truncated cardiac na channel proteins and a reduction in normal na channels . in the extracellular matrix ros promotes cardiac fibrotic process ( via tgf- ) with reduction in conduction velocity and impaired myocyte - myocyte coupling due to collagen deposition .
ros impairs gap junction affecting assembling of cx43 , resulting in reduced myocyte coupling and velocity facilitation of reentry .
activation of ca / cam - dependent kinase ii , c - src tyrosine kinase , protein kinase c , and abnormal splicing of cardiac na channels are among the recently discovered molecular mechanisms of ros - induced arrhythmia .
ros produces ncx activation , increasing inward current afterdepolarization and increasing late na current ( phase 2 of action potential ) facilitating afterdepolarization .
a new selective cardiac late na current inhibitor confers concurrent protection against autonomically induced atrial premature beats ( apbs ) , and dual protection against vulnerability to ischemia - induced af , and reduces atrial and ventricular repolarization abnormalities before and during adrenergic stimulation without negative inotropic effects . in summary
, ros affects camkii : ca / calmodulin - dependent protein kinases ii ; cx43 : connexin 43 ; ncx : na / ca exchanger ; plb : phospholamban ; ryr : ryanodine receptor ; serca : sarco-/endoplasmic reticulum ca - atpase ; tgf- : transforming growth factor- ; zo-1 : zonula occludens-1 . fig . 1 shows the main action points of ros .
1 ) excess of reactive oxygen species ( ros ) ; 2 ) camkii activation or ca / calmodulin - dependent protein kinases ii ; 3 ) c - src activation ( src proto - oncogene , non - receptor tyrosine kinase ) ; 4 ) pkc ( protein kinase c ) enzymes play important roles in several signal transduction cascades .
abnormal splicing , activation of camkii , c - src , and pkc are among emerging new antiarrhythmic ; 5 ) mrna of na current ; 6 ) impair gap junction cx43 conduction resulting in reduced myocyte coupling ; 7 ) ncx : na / ca exchanger .
the ncx removes a single ca ion in exchange for the import of three na ions .
it is considered one of the most important cellular mechanisms for removing ca ; 8) phospholamban ( plb ) : it is a 52-amino acid integral membrane protein that regulates the ca pump in cardiac muscle and skeletal muscle cells ; 9 ) ryanodine receptor ( ryr ) participates in different signaling pathways involving ca release from intracellular organelles .
it is the major cellular mediator of ca induced ca release ( cicr ) in animal cells .
ryr2 is primarily expressed in myocardium ; 10 ) sarco-/endoplasmic reticulum ca - atpase ( serca ) resides in the sarcoplasmic reticulum ( sr ) within myocytes .
it is a ca atpase that transfers ca from the cytosol of the cell to the lumen of the sr at the expense of atp hydrolysis during muscle relaxation ; 11 ) transforming growth factor- ( tgf- ) leads to the activation of different downstream substrates and regulatory proteins , inducing transcription of different target genes that function in differentiation , chemotaxis , proliferation , and activation of many immune cells ; 12 ) zonula occludens-1 ( zo-1 ) or tight junction protein .
the encoded protein may be involved in signal transduction at cell cell junctions ; 13 ) extracellular fibroblasts activation and collagen deposition ; 14 ) increase in l - type ca current ; 15 ) increase in late na current .
selective inhibition of cardiac late ina with eleclazine confers dual protection against vulnerability to ischemia - induced af and reduces atrial and ventricular repolarization abnormalities before and during adrenergic stimulation without negative inotropic effects .
16 ) na current reduction ; 17 ) atp - sensitive k channel ( katp channel ) inhibition ; 18 ) ito , iks and ikr inhibition ; 19 ) transcription ; 20 ) splicing ; 21 ) microrna ; 22 ) translation .
pwd 40 ms indicates the presence of heterogeneous electrical activity in different regions of the atrium that might cause atrial tachyarrhythmias ( atas ) .
a)physiologicalyoung athletes of high performance : pwd is increased in young athletes of high performance and is positively correlated with training duration and baseline heart rate . the increase in pwd is secondary to a significant decrease in pmin .b)pathological1.cardiovascular disordershypertension : hypertension associated with left ventricular hypertrophy , diastolic dysfunction and increased left atrium ( la ) diameter / volume are associated with pwd , a marker for af .coronary artery disease coronary slow flow ( csf ) : csf may be related to increased pwd and corrected qt dispersion ( qtcd ) , a prolonged tp - e interval , and tp - e / qt ratio , and impaired diastolic filling .
trimetazidine , a cytoprotective anti - ischemic agent may restore these parameters .cardiac heart failure ( chf ) : the systolic and diastolic functions are important prognostic indicators of a number of cardiac conditions , and problems with these functions are significant causes of chf .
the la volume has also been reported to be strongly associated with systolic and diastolic dysfunction and is considered to be an index of atrial remodeling .
p - wave abnormalities have been reported to be associated with left atrial enlargement ( lae ) .
the la diameter was significantly higher , and the left ventricle ejection fraction ( lvef ) was significantly lower in patients with dilated cardiomyopathy .
a disturbance in interatrial conduction and an inhomogeneous propagation of the sinus impulse in patients with chf is associated with an increase in pwd , la volume and a deleterious systolic and diastolic dysfunction .valvular heart disease:transcatheter aortic valve replacement ( tavr ) in severe aortic stenosis ( as ) : in patients with severe aortic stenosis , p - wave duration and pwd were shown to be increased , indicating atrial electrical remodeling .
p - wave duration and pwd were significantly decreased at the 6-months of follow - up on post - tavr indicating early reverse atrial electrical remodeling .mitral stenosis ( ms ) and percutaneous transvenous mitral commissurotomy ( ptmc ) : ms is associated with prolonged inter- and intraatrial electromechanical delays and increased pwd , which are markers of af risk .
successful ptmc has a favorable early impact on inter and intraatrial electromechanical delays , which are considered as novel parameters of atrial electromechanical remodeling in ms patients .cardiac surgery : pwd predicts af after cardiac surgery .cryoballoon
ablation for atrial fibrillation : after cryoablation a significant decrease of pwd was observed compared to preprocedural measurements .cardiac resynchronization therapy ( crt ) : this procedure causes decreased p - wave maximum duration and pwd along with an improvement of lvef and a reduction of la diameter with prevention of af .left atrial appendage exclusion in patients with af to prevent thrombus formation : produces decreased atrial mass and decreased pwd by reverse electrical atrial remodeling .after pulmonary vein isolation in patients with normal left atrial dimension : p - wave duration 120ms and pwd are independently associated with higher recurrence rates of af after pulmonary vein isolation .
there is a significant decrease in p - wave duration and pwd after combined percutaneous left atrial appendage ligation and pulmonary vein isolation ( pvi ) in patients with persistent af converted to sinus rhythm .children with neurally mediated syncope : pwd is a useful ecg predictor of cardiac autonomic dysfunction in children with vasovagal syncope .cardiac tumors ( left atrial ( la ) myxoma ) : pwd is a parameter for the prediction of postoperative af in patients with la myxoma
logistic regression analysis revealed pwd as independent predictors of postoperative af .congenital heart disease1)transcatheter closure of an atrial septal defect in children : pwd measurements decrease over time from before the procedure and after one year .
there are no pwd differences in transcatheter closures using the amplatzer septal occluder one year after the procedure .2)transposition of great arteries ( tga ) after uncomplicated arterial switch operation ( aso ) : first - degree block and right bundle branch were detected after procedure .
in addition , the presence of pwd may increase the risk of atrial arrhythmia .hypertrophic cardiomyopathy : pwd together with la phasic functions , and n - terminal pro - brain natriuretic peptide ( nt - probnp ) levels , predict development of af .channelopathies : intraatrial conduction delay with significantly longer p - wave duration , pwd and more percentage of late potentials than the matched controls .
in literature , a special attention is seen devoted to the use of techniques to average the signals in studying p - wave , with the aim of detecting patients susceptible to af . several studies
proved that individuals with a clinical history of paf have intraatrial and interatrial conduction significantly longer in sinus rhythm .
the presence of atrial lps indicates risk of af , since p - wave - triggered signal - averaged ecg ( saecg ) enables to detect slow conduction , even in small areas of the atrium .
atrial heterogeneity may exist in brugada syndrome ( brs ) patients , especially those showing type 1 ecg patterns .
these atrial electrical abnormalities could be a substrate for atrial reentrant tachycardia such as af . among the studied 12-lead ecg parameters , brs subjects with atas exhibit increased values of p - wave duration , pwd , pr interval in lead ii , qrs duration , tpeak - end interval in lead ii and v2 , and tpeak - end dispersion of the 12 leads in relation to those without atas . among the assessed electrophysiological parameters , atrial - his ( ah ) and his - ventricular ( hv ) intervals are significantly prolonged in subjects with atas .
all these parameters are independent predictors of atas in subjects with brs .2.metabolic - endocrine diseasesdiabetes mellitus : diabetes mellitus is an independent and strong risk factor for development of af .
there is a significant atrial electromechanical delay and pwd in patients with type 2 diabetes mellitus when compared with healthy volunteers .insulin resistance in obese adolescents : it is a significant , independent predictor of pwd .hypothyroidism : in the pediatric population hypothyroidism causes atrial electromechanical conduction delay , abnormal p - wave dispersion , and ventricle diastolic dysfunction .diabetes insipidus : diabetes insipidus patients without any cardiovascular disease or risk factors displayed significantly shorter qrs duration and increased pwd compared with controls .
it was significantly correlated with serum osmolality and hyponatremia observed in severe cases .non - alcoholic fatty liver disease ( nafld ) without cardiac disease , diabetes , or hypertension : in a population of nafld without any clinical diagnosis of cardiac disease , diabetes , hypertension , increased left atrial volume , pwd was significantly higher when compared with controls .weight loss and p - wave dispersion in obese patients : p - wave duration and pwd are significantly reduced in patients who lost more than 5% of weight and this decrease is highly related to the extent of weight loss .3.renal diseasesrenal failure : pwd is positively associated with overall and cardiovascular mortality in hemodialysis patients .hemodialysis ( hd ) versus hemodiafiltration ( hdf ) : p - wave duration and pwd are significantly increased during hd . on the other hand , hdf has a more beneficial effect on p - wave duration and pwd than hd , because the la diameter decreased significantly only during hdf .
the decrease in la diameter during hdf is negatively correlated with the incidence of apbs .
hdf has a more beneficial effect on p - wave duration and pwd than hd .4.respiratory diseaseschronic obstructive pulmonary disease ( copd ) : secondary pulmonary hypertension attributable to copd can affect right atrial ( ra ) function without causing gross enlargement in the early stages leading to secondary atrial dysfunction and atrial arrhythmias .
secondary pulmonary hypertension is included in the comorbidity criteria of chf , a condition associated with pwd by heterogeneous atrial depolarization that predisposes to af in copd independent of lung function , blood gas and electrolyte levels , and atrial function .moderate
/ severe obstructive sleep apnea - hypopnea index 15 treated with nasal continuous positive airway pressure : three - month therapy significantly decreased pwd .respiratory maneuvers simulating obstructive sleep apnea in healthy subjects and in patients with paf : intrathoracic pressure swings pwd and therefore may represent an independent trigger factor for the development of paf .nasal septum deviation : preoperative pwd and qtcd values were significantly higher in nasal septum deviation patients than in the control group ( pd : 57.40 14.21 vs 34.11 7.12 milliseconds , p < 0.001 .5.neurological / psychiatric disordersmyotonic dystrophy type 1 ( md1 ) : a significantly increased p - wave duration and pwd in these patients compared with age and sex - matched healthy controls .
additionally , a statistically significant increase in pdw and pmax in md1 patient 's subgroup with af compared to md1 patients with no arrhythmias .multiple sclerosis : in the group of patients , mean p - wave duration , and pwd were significantly longer than normal controls .anorexia nervosa : increased pwd is observed as a risk for af in adolescents with anorexia nervosa when compared with the group of controls .anxiety disorders
.hypochondriac patients : they have significantly higher pwd than those of healthy matched controls.6.rheumatologic entitiesankylosing spondylitis
.rheumatoid arthritis p - wave duration and pwd was found to be higher in rheumatoid arthritis patients than healthy control subjects .7.gastrointestinal diseasesceliac disease : patients with celiac disease have significantly increased pwd and significantly higher interatrial , intra - left atrial , and intra - ra time than matched healthy controls .8.gynecologic
diseasespolycystic ovary syndrome ( pcos ) : patients with pcos had increased inter and intraatrial conduction delays , and decreased la passive emptying volumes and fractions .preeclamptic pregnant women in the late third trimester : the duration of atrial electromechanical delay and pwd is prolonged in this population of patients , .women with intrahepatic cholestasis of pregnancy : in this entity p - wave duration and pwd are significantly prolonged when compared to the normal controls .9.drugs and pwdcombined sedation with midazolam and propofol : pwd values increased after endoscopy with a combination of midazolam and propofol sedation .the effect of trimetazidine : it is an anti - ischemic ( antianginal ) metabolic agent , which improves myocardial glucose utilization through inhibition of fatty acid metabolism , also known as fatty acid oxidation inhibitor .
additionally , the drug improves cardiac function in chf patients and may improve pmax and pwd .10.hematological entitiesthe association of red cell distribution width ( rdw ) and pwd : rdw is a measure of the variation in sizes of peripheral blood erythrocytes .
the parameter is an independent risk factor for new - onset af such as pwd .
elevated rdw values are caused by ferropenic anemia , deficit of vitamin b12 , or folic acid ; increased erythrocyte damage ; and chronic inflammation .
physiologicalyoung athletes of high performance : pwd is increased in young athletes of high performance and is positively correlated with training duration and baseline heart rate .
young athletes of high performance : pwd is increased in young athletes of high performance and is positively correlated with training duration and baseline heart rate .
pathological1.cardiovascular disordershypertension : hypertension associated with left ventricular hypertrophy , diastolic dysfunction and increased left atrium ( la ) diameter / volume are associated with pwd , a marker for af .coronary artery disease coronary slow flow ( csf ) : csf may be related to increased pwd and corrected qt dispersion ( qtcd ) , a prolonged tp - e interval , and tp - e / qt ratio , and impaired diastolic filling .
trimetazidine , a cytoprotective anti - ischemic agent may restore these parameters .cardiac heart failure ( chf ) : the systolic and diastolic functions are important prognostic indicators of a number of cardiac conditions , and problems with these functions are significant causes of chf .
the la volume has also been reported to be strongly associated with systolic and diastolic dysfunction and is considered to be an index of atrial remodeling .
p - wave abnormalities have been reported to be associated with left atrial enlargement ( lae ) .
the la diameter was significantly higher , and the left ventricle ejection fraction ( lvef ) was significantly lower in patients with dilated cardiomyopathy .
a disturbance in interatrial conduction and an inhomogeneous propagation of the sinus impulse in patients with chf is associated with an increase in pwd , la volume and a deleterious systolic and diastolic dysfunction .valvular heart disease:transcatheter aortic valve replacement ( tavr ) in severe aortic stenosis ( as ) : in patients with severe aortic stenosis , p - wave duration and pwd were shown to be increased , indicating atrial electrical remodeling .
p - wave duration and pwd were significantly decreased at the 6-months of follow - up on post - tavr indicating early reverse atrial electrical remodeling .mitral stenosis ( ms ) and percutaneous transvenous mitral commissurotomy ( ptmc ) : ms is associated with prolonged inter- and intraatrial electromechanical delays and increased pwd , which are markers of af risk .
successful ptmc has a favorable early impact on inter and intraatrial electromechanical delays , which are considered as novel parameters of atrial electromechanical remodeling in ms patients .cardiac surgery : pwd predicts af after cardiac surgery .cryoballoon
ablation for atrial fibrillation : after cryoablation a significant decrease of pwd was observed compared to preprocedural measurements .cardiac resynchronization therapy ( crt ) : this procedure causes decreased p - wave maximum duration and pwd along with an improvement of lvef and a reduction of la diameter with prevention of af .left atrial appendage exclusion in patients with af to prevent thrombus formation : produces decreased atrial mass and decreased pwd by reverse electrical atrial remodeling .after pulmonary vein isolation in patients with normal left atrial dimension : p - wave duration 120ms and pwd are independently associated with higher recurrence rates of af after pulmonary vein isolation .
there is a significant decrease in p - wave duration and pwd after combined percutaneous left atrial appendage ligation and pulmonary vein isolation ( pvi ) in patients with persistent af converted to sinus rhythm .children with neurally mediated syncope : pwd is a useful ecg predictor of cardiac autonomic dysfunction in children with vasovagal syncope .cardiac tumors ( left atrial ( la ) myxoma ) : pwd is a parameter for the prediction of postoperative af in patients with la myxoma .
logistic regression analysis revealed pwd as independent predictors of postoperative af .congenital heart disease1)transcatheter closure of an atrial septal defect in children : pwd measurements decrease over time from before the procedure and after one year .
there are no pwd differences in transcatheter closures using the amplatzer septal occluder one year after the procedure .2)transposition of great arteries ( tga ) after uncomplicated arterial switch operation ( aso ) : first - degree block and right bundle branch were detected after procedure .
in addition , the presence of pwd may increase the risk of atrial arrhythmia .hypertrophic cardiomyopathy : pwd together with la phasic functions , and n - terminal pro - brain natriuretic peptide ( nt - probnp ) levels , predict development of af .channelopathies : intraatrial conduction delay with significantly longer p - wave duration , pwd and more percentage of late potentials than the matched controls . in literature , a special attention is seen devoted to the use of techniques to average the signals in studying p - wave , with the aim of detecting patients susceptible to af .
several studies proved that individuals with a clinical history of paf have intraatrial and interatrial conduction significantly longer in sinus rhythm .
the presence of atrial lps indicates risk of af , since p - wave - triggered signal - averaged ecg ( saecg ) enables to detect slow conduction , even in small areas of the atrium .
atrial heterogeneity may exist in brugada syndrome ( brs ) patients , especially those showing type 1 ecg patterns .
these atrial electrical abnormalities could be a substrate for atrial reentrant tachycardia such as af . among the studied 12-lead ecg parameters ,
brs subjects with atas exhibit increased values of p - wave duration , pwd , pr interval in lead ii , qrs duration , tpeak - end interval in lead ii and v2 , and tpeak - end dispersion of the 12 leads in relation to those without atas . among the assessed electrophysiological parameters , atrial - his ( ah ) and his - ventricular ( hv ) intervals
all these parameters are independent predictors of atas in subjects with brs .2.metabolic - endocrine diseasesdiabetes mellitus : diabetes mellitus is an independent and strong risk factor for development of af .
there is a significant atrial electromechanical delay and pwd in patients with type 2 diabetes mellitus when compared with healthy volunteers .insulin resistance in obese adolescents : it is a significant , independent predictor of pwd .hypothyroidism : in the pediatric population hypothyroidism causes atrial electromechanical conduction delay , abnormal p - wave dispersion , and ventricle diastolic dysfunction .diabetes insipidus : diabetes insipidus patients without any cardiovascular disease or risk factors displayed significantly shorter qrs duration and increased pwd compared with controls .
it was significantly correlated with serum osmolality and hyponatremia observed in severe cases .non - alcoholic fatty liver disease ( nafld ) without cardiac disease , diabetes , or hypertension : in a population of nafld without any clinical diagnosis of cardiac disease , diabetes , hypertension , increased left atrial volume , pwd was significantly higher when compared with controls .weight loss and p - wave dispersion in obese patients : p - wave duration and pwd are significantly reduced in patients who lost more than 5% of weight and this decrease is highly related to the extent of weight loss .3.renal diseasesrenal failure : pwd is positively associated with overall and cardiovascular mortality in hemodialysis patients .hemodialysis ( hd ) versus hemodiafiltration ( hdf ) : p - wave duration and pwd are significantly increased during hd . on the other hand , hdf has a more beneficial effect on p - wave duration and pwd than hd , because the la diameter decreased significantly only during hdf .
the decrease in la diameter during hdf is negatively correlated with the incidence of apbs .
hdf has a more beneficial effect on p - wave duration and pwd than hd .4.respiratory diseaseschronic obstructive pulmonary disease ( copd ) : secondary pulmonary hypertension attributable to copd can affect right atrial ( ra ) function without causing gross enlargement in the early stages leading to secondary atrial dysfunction and atrial arrhythmias .
secondary pulmonary hypertension is included in the comorbidity criteria of chf , a condition associated with pwd by heterogeneous atrial depolarization that predisposes to af in copd independent of lung function , blood gas and electrolyte levels , and atrial function .moderate
/ severe obstructive sleep apnea - hypopnea index 15 treated with nasal continuous positive airway pressure : three - month therapy significantly decreased pwd .respiratory maneuvers simulating obstructive sleep apnea in healthy subjects and in patients with paf : intrathoracic pressure swings pwd and therefore may represent an independent trigger factor for the development of paf .nasal septum deviation : preoperative pwd and qtcd values were significantly higher in nasal septum deviation patients than in the control group ( pd : 57.40 14.21 vs 34.11 7.12 milliseconds , p < 0.001 .5.neurological / psychiatric disordersmyotonic dystrophy type 1 ( md1 ) : a significantly increased p - wave duration and pwd in these patients compared with age and sex - matched healthy controls .
additionally , a statistically significant increase in pdw and pmax in md1 patient 's subgroup with af compared to md1 patients with no arrhythmias .multiple sclerosis : in the group of patients , mean p - wave duration , and pwd were significantly longer than normal controls .anorexia nervosa : increased pwd is observed as a risk for af in adolescents with anorexia nervosa when compared with the group of controls .anxiety disorders
.hypochondriac patients : they have significantly higher pwd than those of healthy matched controls.6.rheumatologic entitiesankylosing spondylitis
.rheumatoid arthritis p - wave duration and pwd was found to be higher in rheumatoid arthritis patients than healthy control subjects .7.gastrointestinal diseasesceliac disease : patients with celiac disease have significantly increased pwd and significantly higher interatrial , intra - left atrial , and intra - ra time than matched healthy controls .8.gynecologic diseasespolycystic ovary syndrome ( pcos ) : patients with pcos had increased inter and intraatrial conduction delays , and decreased la passive emptying volumes and fractions .preeclamptic pregnant women in the late third trimester : the duration of atrial electromechanical delay and pwd is prolonged in this population of patients , .women with intrahepatic cholestasis of pregnancy : in this entity p - wave duration and pwd are significantly prolonged when compared to the normal controls .9.drugs and pwdcombined sedation with midazolam and propofol : pwd values increased after endoscopy with a combination of midazolam and propofol sedation .the effect of trimetazidine : it is an anti - ischemic ( antianginal ) metabolic agent , which improves myocardial glucose utilization through inhibition of fatty acid metabolism , also known as fatty acid oxidation inhibitor .
additionally , the drug improves cardiac function in chf patients and may improve pmax and pwd .10.hematological entitiesthe association of red cell distribution width ( rdw ) and pwd : rdw is a measure of the variation in sizes of peripheral blood erythrocytes .
the parameter is an independent risk factor for new - onset af such as pwd .
elevated rdw values are caused by ferropenic anemia , deficit of vitamin b12 , or folic acid ; increased erythrocyte damage ; and chronic inflammation .
cardiovascular disordershypertension : hypertension associated with left ventricular hypertrophy , diastolic dysfunction and increased left atrium ( la ) diameter / volume are associated with pwd , a marker for af .coronary artery disease coronary slow flow ( csf ) : csf may be related to increased pwd and corrected qt dispersion ( qtcd ) , a prolonged tp - e interval , and tp - e / qt ratio , and impaired diastolic filling .
trimetazidine , a cytoprotective anti - ischemic agent may restore these parameters .cardiac heart failure ( chf ) : the systolic and diastolic functions are important prognostic indicators of a number of cardiac conditions , and problems with these functions are significant causes of chf .
the la volume has also been reported to be strongly associated with systolic and diastolic dysfunction and is considered to be an index of atrial remodeling .
p - wave abnormalities have been reported to be associated with left atrial enlargement ( lae ) .
the la diameter was significantly higher , and the left ventricle ejection fraction ( lvef ) was significantly lower in patients with dilated cardiomyopathy .
a disturbance in interatrial conduction and an inhomogeneous propagation of the sinus impulse in patients with chf is associated with an increase in pwd , la volume and a deleterious systolic and diastolic dysfunction .valvular heart disease:transcatheter aortic valve replacement ( tavr ) in severe aortic stenosis ( as ) : in patients with severe aortic stenosis , p - wave duration and pwd were shown to be increased , indicating atrial electrical remodeling .
p - wave duration and pwd were significantly decreased at the 6-months of follow - up on post - tavr indicating early reverse atrial electrical remodeling .mitral stenosis ( ms ) and percutaneous transvenous mitral commissurotomy ( ptmc ) : ms is associated with prolonged inter- and intraatrial electromechanical delays and increased pwd , which are markers of af risk .
successful ptmc has a favorable early impact on inter and intraatrial electromechanical delays , which are considered as novel parameters of atrial electromechanical remodeling in ms patients .cardiac surgery : pwd predicts af after cardiac surgery .cryoballoon
ablation for atrial fibrillation : after cryoablation a significant decrease of pwd was observed compared to preprocedural measurements .cardiac resynchronization therapy ( crt ) : this procedure causes decreased p - wave maximum duration and pwd along with an improvement of lvef and a reduction of la diameter with prevention of af .left atrial appendage exclusion in patients with af to prevent thrombus formation : produces decreased atrial mass and decreased pwd by reverse electrical atrial remodeling .after pulmonary vein isolation in patients with normal left atrial dimension : p - wave duration 120ms and pwd are independently associated with higher recurrence rates of af after pulmonary vein isolation .
there is a significant decrease in p - wave duration and pwd after combined percutaneous left atrial appendage ligation and pulmonary vein isolation ( pvi ) in patients with persistent af converted to sinus rhythm .children with neurally mediated syncope : pwd is a useful ecg predictor of cardiac autonomic dysfunction in children with vasovagal syncope .cardiac tumors ( left atrial ( la ) myxoma ) : pwd is a parameter for the prediction of postoperative af in patients with la myxoma
logistic regression analysis revealed pwd as independent predictors of postoperative af .congenital heart disease1)transcatheter closure of an atrial septal defect in children : pwd measurements decrease over time from before the procedure and after one year .
there are no pwd differences in transcatheter closures using the amplatzer septal occluder one year after the procedure .2)transposition of great arteries ( tga ) after uncomplicated arterial switch operation ( aso ) : first - degree block and right bundle branch were detected after procedure .
in addition , the presence of pwd may increase the risk of atrial arrhythmia .hypertrophic cardiomyopathy : pwd together with la phasic functions , and n - terminal pro - brain natriuretic peptide ( nt - probnp ) levels , predict development of af .channelopathies : intraatrial conduction delay with significantly longer p - wave duration , pwd and more percentage of late potentials than the matched controls . in literature , a special attention is seen devoted to the use of techniques to average the signals in studying p - wave , with the aim of detecting patients susceptible to af .
several studies proved that individuals with a clinical history of paf have intraatrial and interatrial conduction significantly longer in sinus rhythm .
the presence of atrial lps indicates risk of af , since p - wave - triggered signal - averaged ecg ( saecg ) enables to detect slow conduction , even in small areas of the atrium .
atrial heterogeneity may exist in brugada syndrome ( brs ) patients , especially those showing type 1 ecg patterns .
these atrial electrical abnormalities could be a substrate for atrial reentrant tachycardia such as af . among the studied 12-lead ecg parameters , brs subjects with atas exhibit increased values of p - wave duration , pwd , pr interval in lead ii , qrs duration , tpeak - end interval in lead ii and v2 , and tpeak - end dispersion of the 12 leads in relation to those without atas . among the assessed electrophysiological parameters , atrial - his ( ah ) and his - ventricular ( hv ) intervals are significantly prolonged in subjects with atas .
all these parameters are independent predictors of atas in subjects with brs . hypertension : hypertension associated with left ventricular hypertrophy , diastolic dysfunction and
increased left atrium ( la ) diameter / volume are associated with pwd , a marker for af .
coronary artery disease coronary slow flow ( csf ) : csf may be related to increased pwd and corrected qt dispersion ( qtcd ) , a prolonged tp - e interval , and tp - e / qt ratio , and impaired diastolic filling .
cardiac heart failure ( chf ) : the systolic and diastolic functions are important prognostic indicators of a number of cardiac conditions , and problems with these functions are significant causes of chf .
the la volume has also been reported to be strongly associated with systolic and diastolic dysfunction and is considered to be an index of atrial remodeling .
p - wave abnormalities have been reported to be associated with left atrial enlargement ( lae ) .
the la diameter was significantly higher , and the left ventricle ejection fraction ( lvef ) was significantly lower in patients with dilated cardiomyopathy .
a disturbance in interatrial conduction and an inhomogeneous propagation of the sinus impulse in patients with chf is associated with an increase in pwd , la volume and a deleterious systolic and diastolic dysfunction .
valvular heart disease:transcatheter aortic valve replacement ( tavr ) in severe aortic stenosis ( as ) : in patients with severe aortic stenosis , p - wave duration and pwd were shown to be increased , indicating atrial electrical remodeling .
p - wave duration and pwd were significantly decreased at the 6-months of follow - up on post - tavr indicating early reverse atrial electrical remodeling .mitral stenosis ( ms ) and percutaneous transvenous mitral commissurotomy ( ptmc ) : ms is associated with prolonged inter- and intraatrial electromechanical delays and increased pwd , which are markers of af risk .
successful ptmc has a favorable early impact on inter and intraatrial electromechanical delays , which are considered as novel parameters of atrial electromechanical remodeling in ms patients .
transcatheter aortic valve replacement ( tavr ) in severe aortic stenosis ( as ) : in patients with severe aortic stenosis , p - wave duration and pwd were shown to be increased , indicating atrial electrical remodeling .
p - wave duration and pwd were significantly decreased at the 6-months of follow - up on post - tavr indicating early reverse atrial electrical remodeling .
mitral stenosis ( ms ) and percutaneous transvenous mitral commissurotomy ( ptmc ) : ms is associated with prolonged inter- and intraatrial electromechanical delays and increased pwd , which are markers of af risk .
successful ptmc has a favorable early impact on inter and intraatrial electromechanical delays , which are considered as novel parameters of atrial electromechanical remodeling in ms patients .
cryoballoon ablation for atrial fibrillation : after cryoablation a significant decrease of pwd was observed compared to preprocedural measurements . cardiac resynchronization therapy ( crt ) : this procedure causes decreased p - wave maximum duration and pwd along with an improvement of lvef and a reduction of la diameter with prevention of af .
left atrial appendage exclusion in patients with af to prevent thrombus formation : produces decreased atrial mass and decreased pwd by reverse electrical atrial remodeling .
after pulmonary vein isolation in patients with normal left atrial dimension : p - wave duration 120ms and pwd are independently associated with higher recurrence rates of af after pulmonary vein isolation .
there is a significant decrease in p - wave duration and pwd after combined percutaneous left atrial appendage ligation and pulmonary vein isolation ( pvi ) in patients with persistent af converted to sinus rhythm .
children with neurally mediated syncope : pwd is a useful ecg predictor of cardiac autonomic dysfunction in children with vasovagal syncope .
cardiac tumors ( left atrial ( la ) myxoma ) : pwd is a parameter for the prediction of postoperative af in patients with la myxoma
congenital heart disease1)transcatheter closure of an atrial septal defect in children : pwd measurements decrease over time from before the procedure and after one year .
there are no pwd differences in transcatheter closures using the amplatzer septal occluder one year after the procedure .2)transposition of great arteries ( tga ) after uncomplicated arterial switch operation ( aso ) : first - degree block and right bundle branch were detected after procedure .
transcatheter closure of an atrial septal defect in children : pwd measurements decrease over time from before the procedure and after one year .
there are no pwd differences in transcatheter closures using the amplatzer septal occluder one year after the procedure .
transposition of great arteries ( tga ) after uncomplicated arterial switch operation ( aso ) : first - degree block and right bundle branch were detected after procedure .
hypertrophic cardiomyopathy : pwd together with la phasic functions , and n - terminal pro - brain natriuretic peptide ( nt - probnp ) levels , predict development of af .
channelopathies : intraatrial conduction delay with significantly longer p - wave duration , pwd and more percentage of late potentials than the matched controls . in literature , a special attention
is seen devoted to the use of techniques to average the signals in studying p - wave , with the aim of detecting patients susceptible to af .
several studies proved that individuals with a clinical history of paf have intraatrial and interatrial conduction significantly longer in sinus rhythm .
the presence of atrial lps indicates risk of af , since p - wave - triggered signal - averaged ecg ( saecg ) enables to detect slow conduction , even in small areas of the atrium .
atrial heterogeneity may exist in brugada syndrome ( brs ) patients , especially those showing type 1 ecg patterns .
these atrial electrical abnormalities could be a substrate for atrial reentrant tachycardia such as af . among the studied 12-lead ecg parameters , brs subjects with atas exhibit increased values of p - wave duration , pwd , pr interval in lead ii , qrs duration , tpeak - end interval in lead ii and v2 , and tpeak - end dispersion of the 12 leads in relation to those without atas . among the assessed electrophysiological parameters , atrial - his ( ah ) and his - ventricular ( hv ) intervals are significantly prolonged in subjects with atas .
metabolic - endocrine diseasesdiabetes mellitus : diabetes mellitus is an independent and strong risk factor for development of af .
there is a significant atrial electromechanical delay and pwd in patients with type 2 diabetes mellitus when compared with healthy volunteers .insulin resistance in obese adolescents : it is a significant , independent predictor of pwd .hypothyroidism : in the pediatric population hypothyroidism causes atrial electromechanical conduction delay , abnormal p - wave dispersion , and ventricle diastolic dysfunction .diabetes insipidus : diabetes insipidus patients without any cardiovascular disease or risk factors displayed significantly shorter qrs duration and increased pwd compared with controls .
it was significantly correlated with serum osmolality and hyponatremia observed in severe cases .non - alcoholic fatty liver disease ( nafld ) without cardiac disease , diabetes , or hypertension : in a population of nafld without any clinical diagnosis of cardiac disease , diabetes , hypertension , increased left atrial volume , pwd was significantly higher when compared with controls .weight loss and p - wave dispersion in obese patients : p - wave duration and pwd are significantly reduced in patients who lost more than 5% of weight and this decrease is highly related to the extent of weight loss .
diabetes mellitus : diabetes mellitus is an independent and strong risk factor for development of af .
there is a significant atrial electromechanical delay and pwd in patients with type 2 diabetes mellitus when compared with healthy volunteers .
insulin resistance in obese adolescents : it is a significant , independent predictor of pwd .
hypothyroidism : in the pediatric population hypothyroidism causes atrial electromechanical conduction delay , abnormal p - wave dispersion , and ventricle diastolic dysfunction .
diabetes insipidus : diabetes insipidus patients without any cardiovascular disease or risk factors displayed significantly shorter qrs duration and increased pwd compared with controls . it was significantly correlated with serum osmolality and hyponatremia observed in severe cases .
non - alcoholic fatty liver disease ( nafld ) without cardiac disease , diabetes , or hypertension : in a population of nafld without any clinical diagnosis of cardiac disease , diabetes , hypertension , increased left atrial volume , pwd was significantly higher when compared with controls .
weight loss and p - wave dispersion in obese patients : p - wave duration and pwd are significantly reduced in patients who lost more than 5% of weight and this decrease is highly related to the extent of weight loss .
renal diseasesrenal failure : pwd is positively associated with overall and cardiovascular mortality in hemodialysis patients .hemodialysis ( hd ) versus hemodiafiltration ( hdf ) : p - wave duration and pwd are significantly increased during hd . on the other hand , hdf has a more beneficial effect on p - wave duration and pwd than hd , because the la diameter decreased significantly only during hdf .
the decrease in la diameter during hdf is negatively correlated with the incidence of apbs .
hdf has a more beneficial effect on p - wave duration and pwd than hd .
renal failure : pwd is positively associated with overall and cardiovascular mortality in hemodialysis patients . hemodialysis ( hd ) versus hemodiafiltration ( hdf ) : p - wave duration and pwd are significantly increased during hd . on the other hand , hdf has a more beneficial effect on p - wave duration and pwd than hd , because the la diameter decreased significantly only during hdf .
the decrease in la diameter during hdf is negatively correlated with the incidence of apbs .
hdf has a more beneficial effect on p - wave duration and pwd than hd .
respiratory diseaseschronic obstructive pulmonary disease ( copd ) : secondary pulmonary hypertension attributable to copd can affect right atrial ( ra ) function without causing gross enlargement in the early stages leading to secondary atrial dysfunction and atrial arrhythmias .
secondary pulmonary hypertension is included in the comorbidity criteria of chf , a condition associated with pwd by heterogeneous atrial depolarization that predisposes to af in copd independent of lung function , blood gas and electrolyte levels , and atrial function .moderate
/ severe obstructive sleep apnea - hypopnea index 15 treated with nasal continuous positive airway pressure : three - month therapy significantly decreased pwd .respiratory maneuvers simulating obstructive sleep apnea in healthy subjects and in patients with paf : intrathoracic pressure swings pwd and therefore may represent an independent trigger factor for the development of paf .nasal septum deviation : preoperative pwd and qtcd values were significantly higher in nasal septum deviation patients than in the control group ( pd : 57.40 14.21 vs 34.11 7.12 milliseconds , p < 0.001 .
chronic obstructive pulmonary disease ( copd ) : secondary pulmonary hypertension attributable to copd can affect right atrial ( ra ) function without causing gross enlargement in the early stages leading to secondary atrial dysfunction and atrial arrhythmias .
secondary pulmonary hypertension is included in the comorbidity criteria of chf , a condition associated with pwd by heterogeneous atrial depolarization that predisposes to af in copd independent of lung function , blood gas and electrolyte levels , and atrial function .
moderate / severe obstructive sleep apnea - hypopnea index 15 treated with nasal continuous positive airway pressure : three - month therapy significantly decreased pwd .
respiratory maneuvers simulating obstructive sleep apnea in healthy subjects and in patients with paf : intrathoracic pressure swings pwd and therefore may represent an independent trigger factor for the development of paf . nasal septum deviation :
preoperative pwd and qtcd values were significantly higher in nasal septum deviation patients than in the control group ( pd : 57.40 14.21 vs 34.11 7.12 milliseconds , p < 0.001 .
neurological / psychiatric disordersmyotonic dystrophy type 1 ( md1 ) : a significantly increased p - wave duration and pwd in these patients compared with age and sex - matched healthy controls .
additionally , a statistically significant increase in pdw and pmax in md1 patient 's subgroup with af compared to md1 patients with no arrhythmias .multiple sclerosis : in the group of patients , mean p - wave duration , and pwd were significantly longer than normal controls .anorexia nervosa : increased pwd is observed as a risk for af in adolescents with anorexia nervosa when compared with the group of controls .anxiety disorders
.hypochondriac patients : they have significantly higher pwd than those of healthy matched controls .
myotonic dystrophy type 1 ( md1 ) : a significantly increased p - wave duration and pwd in these patients compared with age and sex - matched healthy controls .
additionally , a statistically significant increase in pdw and pmax in md1 patient 's subgroup with af compared to md1 patients with no arrhythmias .
multiple sclerosis : in the group of patients , mean p - wave duration , and pwd were significantly longer than normal controls .
anorexia nervosa : increased pwd is observed as a risk for af in adolescents with anorexia nervosa when compared with the group of controls .
rheumatologic entitiesankylosing spondylitis
.rheumatoid arthritis p - wave duration and pwd was found to be higher in rheumatoid arthritis patients than healthy control subjects .
rheumatoid arthritis p - wave duration and pwd was found to be higher in rheumatoid arthritis patients than healthy control subjects .
gastrointestinal diseasesceliac disease : patients with celiac disease have significantly increased pwd and significantly higher interatrial , intra - left atrial , and intra - ra time than matched healthy controls .
celiac disease : patients with celiac disease have significantly increased pwd and significantly higher interatrial , intra - left atrial , and intra - ra time than matched healthy controls . gynecologic diseasespolycystic ovary syndrome ( pcos ) : patients with pcos had increased inter and intraatrial conduction delays , and decreased la passive emptying volumes and fractions .preeclamptic pregnant women in the late third trimester : the duration of atrial electromechanical delay and pwd is prolonged in this population of patients , .women with intrahepatic cholestasis of pregnancy : in this entity p - wave duration and pwd are significantly prolonged when compared to the normal controls .
polycystic ovary syndrome ( pcos ) : patients with pcos had increased inter and intraatrial conduction delays , and decreased la passive emptying volumes and fractions .
preeclamptic pregnant women in the late third trimester : the duration of atrial electromechanical delay and pwd is prolonged in this population of patients , . women with intrahepatic cholestasis of pregnancy : in this entity p - wave duration and pwd are significantly prolonged when compared to the normal controls .
drugs and pwdcombined sedation with midazolam and propofol : pwd values increased after endoscopy with a combination of midazolam and propofol sedation .the effect of trimetazidine : it is an anti - ischemic ( antianginal ) metabolic agent , which improves myocardial glucose utilization through inhibition of fatty acid metabolism , also known as fatty acid oxidation inhibitor .
additionally , the drug improves cardiac function in chf patients and may improve pmax and pwd .
combined sedation with midazolam and propofol : pwd values increased after endoscopy with a combination of midazolam and propofol sedation .
the effect of trimetazidine : it is an anti - ischemic ( antianginal ) metabolic agent , which improves myocardial glucose utilization through inhibition of fatty acid metabolism , also known as fatty acid oxidation inhibitor .
additionally , the drug improves cardiac function in chf patients and may improve pmax and pwd .
hematological entitiesthe association of red cell distribution width ( rdw ) and pwd : rdw is a measure of the variation in sizes of peripheral blood erythrocytes .
the parameter is an independent risk factor for new - onset af such as pwd .
elevated rdw values are caused by ferropenic anemia , deficit of vitamin b12 , or folic acid ; increased erythrocyte damage ; and chronic inflammation .
the association of red cell distribution width ( rdw ) and pwd : rdw is a measure of the variation in sizes of peripheral blood erythrocytes .
the parameter is an independent risk factor for new - onset af such as pwd .
elevated rdw values are caused by ferropenic anemia , deficit of vitamin b12 , or folic acid ; increased erythrocyte damage ; and chronic inflammation .
they are : p - wave duration , p - wave amplitude or voltage , p - wave polarity , p - wave axis in the frontal plane , p - wave shape or morphology , and pwd ( main object of our revision).i.p - wave duration : normal value in adults is 60110 ms ( 1.52.75 small boxes ) < 120 ms or 0.12 s ( three small boxes ) . over the years , the p - wave duration progressively increases .
table 1 shows normal maximal values of the p - wave duration with the advancement of age .
p - wave duration : normal value in adults is 60110 ms ( 1.52.75 small boxes ) < 120 ms or 0.12 s ( three small boxes ) . over the years
table 1 shows normal maximal values of the p - wave duration with the advancement of age .
p - wave duration measurement onset of the p - wave is defined as the point of first visible upward slope from baseline for positive waveforms ( a ) , and as the point of first downward slope from baseline for negative waveforms ( b ) .
the return to baseline was considered as the end of the p - wave . a and b
represent the improper form of p - wave duration measurement.ii.p-wave amplitude / voltage : maximal normal value < 2.5 mm or 0.25 mv .
p - wave amplitude is between 5 mm or 0.05 mv to 2.5 mm 0.25 mv ( 0.52.5 small boxes ) .
p - wave amplitude / voltage : maximal normal value < 2.5 mm or 0.25 mv .
p - wave amplitude is between 5 mm or 0.05 mv to 2.5 mm 0.25 mv ( 0.52.5 small boxes ) . in
the precordial leads normal p - wave amplitude is always < 1.5 mm.iii.p-wave polarity : always positive in ii , i , avf and from v3 to v6 , always negative in avr and variable in iii , avl and v1v2 .
the normal p - wave is typically biphasic in v1 , with similar sizes of the positive and negative deflections . left
atrial enlargement causes widening ( > 40 ms wide ) and deepening ( > 1 mm deep ) in v1 of the terminal negative portion of the p-wave.iv.p-wave axis in the frontal plane : normal p - axis was considered between 0 and + 75 by manually constructing the mean frontal plane electrical p - axis from standard limb leads .v.p - wave shape or morphology : the shape of a p - wave is usually smooth and rounded .
we may see notched p - waves in the frontal plane in partial interatrial block ( p - iab ) and lae produces a broad ( 120 ms ) , bifid p - wave in lead ii ( p mitrale ) .
p - iab does not have a terminal delayed negative portion of the p - wave in v1 . on the other hand , lae has a positive morris index ( p terminal force in v1 ( ptf - v1 ) = 0.04 mm / s ) .
this is the terminal , negative part of the p - wave in lead v1 expressed as the multiplication of its depth in millimeters and width in seconds ( mm / s ) .
the normal ptf - v1 and p - iab do not exceed 0.04 s wide and 1 mm deep , i.e. , 0.04 mm / s . platonov divided the p - wave morphology using orthogonal leads in three types:type 1 : upright p - waves in all orthogonal leads common in healthy subjects below 50 years of age;type 2 : upright p - waves in leads x and y and biphasic in lead z
common in patients with paf , lae but may also be seen in healthy patients older than 50;type 3 : upright in x but biphasic in leads y and z advanced , complete or third degree interatrial block ( a - iab ) , often associated with prolongation of p - wave > 120 ms .
electrical impulse is blocked / delayed in bachmann 's muscular interatrial bundle ( bb ) , but retrograde left atrial activation usually occurs . note the existence of an open angle between the vector of the first portion of the p - wave ( ra ) and the last portion ( la ) .
the electrophysiological study demonstrates retrograde activation of the la . consequently , p loop / wave in orthogonal lead y , avf and iii is biphasic ( + /-
la activation occurs by an alternate route rather than proceeding from right to left via the bb ( fig .
p - wave polarity : always positive in ii , i , avf and from v3 to v6 , always negative in avr and variable in iii , avl and v1v2 .
the normal p - wave is typically biphasic in v1 , with similar sizes of the positive and negative deflections . left atrial enlargement causes widening ( > 40 ms wide ) and deepening ( > 1 mm deep ) in v1 of the terminal negative portion of the p - wave .
p - wave axis in the frontal plane : normal p - axis was considered between 0 and + 75 by manually constructing the mean frontal plane electrical p - axis from standard limb leads .
p - wave shape or morphology : the shape of a p - wave is usually smooth and rounded .
we may see notched p - waves in the frontal plane in partial interatrial block ( p - iab ) and lae produces a broad ( 120 ms ) , bifid p - wave in lead ii ( p mitrale ) .
p - iab does not have a terminal delayed negative portion of the p - wave in v1 . on the other hand , lae has a positive morris index ( p terminal force in v1 ( ptf - v1 ) = 0.04 mm / s ) .
this is the terminal , negative part of the p - wave in lead v1 expressed as the multiplication of its depth in millimeters and width in seconds ( mm / s ) .
the normal ptf - v1 and p - iab do not exceed 0.04 s wide and 1 mm deep , i.e. , 0.04 mm / s . platonov divided
the p - wave morphology using orthogonal leads in three types:type 1 : upright p - waves in all orthogonal leads common in healthy subjects below 50 years of age;type 2 : upright p - waves in leads x and y and biphasic in lead z common in patients with paf , lae but may also be seen in healthy patients older than 50;type 3 : upright in x but biphasic in leads y and z advanced , complete or third degree interatrial block ( a - iab ) , often associated with prolongation of p - wave > 120 ms .
electrical impulse is blocked / delayed in bachmann 's muscular interatrial bundle ( bb ) , but retrograde left atrial activation usually occurs . note the existence of an open angle between the vector of the first portion of the p - wave ( ra ) and the last portion ( la ) .
the electrophysiological study demonstrates retrograde activation of the la . consequently , p loop / wave in orthogonal lead y , avf and iii is biphasic ( + /-
la activation occurs by an alternate route rather than proceeding from right to left via the bb ( fig .
type 1 : upright p - waves in all orthogonal leads common in healthy subjects below 50 years of age ; type 2 : upright p - waves in leads x and y and biphasic in lead z common in patients with paf , lae but may also be seen in healthy patients older than 50 ; type 3 : upright in x but biphasic in leads y and z advanced , complete or third degree interatrial block ( a - iab ) , often associated with prolongation of p - wave > 120 ms .
electrical impulse is blocked / delayed in bachmann 's muscular interatrial bundle ( bb ) , but retrograde left atrial activation usually occurs . note the existence of an open angle between the vector of the first portion of the p - wave ( ra ) and the last portion ( la ) .
consequently , p loop / wave in orthogonal lead y , avf and iii is biphasic ( + /-
la activation occurs by an alternate route rather than proceeding from right to left via the bb ( fig .
electrical impulse is blocked / delayed in bachmann 's muscular interatrial bundle ( bb ) , but retrograde la activation usually occurs . note the existence of an open angle between the vector of the first portion of p - wave ( ra ) and the last portion ( la ) .
electrophysiological study demonstrates retrograde activation of the la . consequently , p - loop / wave in orthogonal lead y , avf and iii is biphasic ( + /-
la activation occurs by an alternate route rather than proceeding from right to left via the bb . a : anterior internodal bundle ; bb : bachmann 's bundle ; fp : frontal plane ; j : bypass james fascicle
; la : left atrium ; m : middle internodal or wenckebach bundle ; p : posterior internodal or thorel bundle ; ra : right atrium.vi.p-wave dispersion : is defined as the difference between the maximum and the minimum p - wave duration recorded from multiple different - surface ecg leads .
it has been known that increased p - wave duration and pwd reflect prolongation of intraatrial and interatrial conduction time and the inhomogeneous atrial propagation of sinus impulses , which are well - known electrophysiological characteristics in patients with atrial arrhythmias and especially paf .
maximum and minimum p - wave durations are calculated from the standard ecg during sinus rhythm .
pwd is derived by subtracting the minimum p - wave duration from the maximum in any of the 12 ecg leads .
pwd can be calculated by manual measurements ( hand - held caliper measurements ) or computerized methods .
manual measurement with hand - held calipers is performed by increasing the ecg rate to 50 mm / s and the voltage to 1 mv / cm , accompanied by use of magnification . however , hand - held caliper measurements have less accuracy compared with digital measurements .
p - wave dispersion : is defined as the difference between the maximum and the minimum p - wave duration recorded from multiple different - surface ecg leads .
it has been known that increased p - wave duration and pwd reflect prolongation of intraatrial and interatrial conduction time and the inhomogeneous atrial propagation of sinus impulses , which are well - known electrophysiological characteristics in patients with atrial arrhythmias and especially paf .
maximum and minimum p - wave durations are calculated from the standard ecg during sinus rhythm .
pwd is derived by subtracting the minimum p - wave duration from the maximum in any of the 12 ecg leads .
pwd can be calculated by manual measurements ( hand - held caliper measurements ) or computerized methods .
manual measurement with hand - held calipers is performed by increasing the ecg rate to 50 mm / s and the voltage to 1 mv / cm , accompanied by use of magnification . however , hand - held caliper measurements have less accuracy compared with digital measurements .
they are simple ecg markers that could be used to identify the patients with idiopathic paf . a p maximum value of 106 ms separated patients with paf from control subjects with a sensitivity of 83% , a specificity of 72% , and a positive predictive accuracy of 79% .
a pwd value 36 ms separated patients from control subjects with a sensitivity of 77% , a specificity of 82% , and a positive predictive accuracy of 85% . in elderly people in sinus rhythm
this parameter index is measured by both 2-dimensional and 3-dimensional echocardiography and categorized as normal when 34 ml / m or mild increased ( 3541 ml / m ; moderate , 4248 ml / m ; severe , 49 ml / m .
measurement of pwd has not been standardized yet , however , pwd is calculated by subtracting minimum p - wave duration ( p min ) from maximum p - wave duration ( pmax ) , measured from the standard 12-lead surface ecg during sinus rhythm obtained from each patient in supine position following 15 min of rest and room temperature and lighting kept constant ( pwd and pmax are lower in the right lateral decubitus lying position than in other positions ) .
the paper speed must be of 50 mm / s and amplitude at 20 mm / mv for the recording calibration .
manual measurement has less accuracy compared with a computerized digital system . the onset of the p - wave is defined as the point of first detectable upward or downward slope from the isoelectric line for positive or negative waveforms , respectively .
return to the isoelectric line is considered as the end of the p - wave .
table 2 shows the ecg and electrophysiological markers prone to af ( predictors ) .
pwd is revealed as an important parameter of easy measurement that indicates a greater tendency to the appearance of supraventricular arrhythmias , particularly paf .
a pwd value close to 40ms ( one small box with a paper speed of 50ms ) is considered increased having been observed both in physiological and pathological scenarios . increased pwd in elite of athletes explains the higher incidence of af in this population . a task force to determine definitively the pwd normal limits is mandatory .
the molecular substrate involves driving changes affecting the atrial tissue with affectation of numerous sarcolemmal ion channels , gap junctions ( cx43 and cx40 ) leading to degrees of fibrosis in the extracellular tissue of the atria , insufficient blood supply , significant anysoisotropic myoelectric activity , thin wall thickness and consequent expansion tendency all well - known electrophysiological alterations . | p - wave dispersion ( pwd , pd or pdis ) is a noninvasive electrocardiographic ( ecg ) marker for atrial remodeling and predictor for atrial fibrillation ( af ) .
pwd is defined as the difference between the widest and the narrowest p - wave duration recorded from the 12 ecg leads .
increased p - wave duration and pwd reflect prolongation of intraatrial and interatrial conduction time with lack of a well - coordinated conduction system within the atrial muscles , with inhomogeneous , asynchronic , pro - inflammatory and anti - inflammatory effect mediated by interleukin-6 ( il-6 ) in patients with the cg + gg genotype il-6 -634c / g polymorphism [ 1 ] and discontinuous propagation of sinus impulses mainly between the left and right atria , interstitial / extracellular fibroblast activation and collagen deposition with fibrosis ( via tgf- ) in atrial tissue , insufficient blood supply , significant not isotropic myoelectric activity , and thin wall thickness and consequent expansion tendency all well - known electrophysiological characteristics in patients with atrial arrhythmias and especially paroxysmal atrial fibrillation ( paf ) [ 2 ] . |
titanium
dioxide ( tio2 ) nanostructures have attracted
great interest in the past few decades due to their low cost , environmental
compatibility , and experimentally proven potential for photocatalytic and photovoltaic applications .
in particular ,
the use of such nanostructures as heterogeneous catalysts for the
photocatalytic splitting of water to produce renewable hydrogen and in dye - sensitized solar cells has
been the subject of intense research .
recent studies suggest that the size and the shape of tio2 nanostructures
directly influence their performance in these applications and hence
must have a clear effect on the microscopic electron hole pair
production , recombination , separation , and diffusion rates . to understand the physics and chemistry underlying the application
of tio2 nanostructures in photocatalysis and photovoltaics
from a theoretical point of view ,
tio2 nanostructures and
extended systems have been computationally extensively studied using
a variety of methods .
most of these studies employ either ground state density functional
theory ( dft ) or its excited state variant time - dependent density functional
theory ( td - dft ) . in the former case ,
optical excitations are generally
assumed to map onto excitations from occupied to unoccupied kohn
alternatively ,
for the lowest triplet excited state , the excitation is modeled as
a state obtained self - consistently by using a scf approach .
td - dft , in contrast , is a genuine excited state method that can be
used for any number of excitations of any multiplicity .
however , just
like dft in the case of the ground state , td - dft ( and scf )
suffers from the fact that the results are , to a smaller or larger
degree , dependent on the exchange - correlation ( xc ) potential used
.
this might be especially true for tio2 and other transition
metal containing systems .
on the other hand , correlated wave function
methods used in quantum chemistry , e.g. , coupled cluster ( cc ) and
complete active space second order perturbation theory ( caspt2 ) , do
not suffer from this problem and are perhaps the gold standard for
excitation calculations .
however , the poor scaling of such methods
with the number of electrons in the system means that they can only
be used for very small nanoclusters containing merely a few transition
metal atoms .
for example , the largest system studied to date for tio2 using correlated wave function methods is the ( tio2)3 trimer .
the majority of
cc and caspt2 simulations focused on the description of the excited
states of the tio2 monomer . finally , there have
also been studies on tio2 nanostructures using green s
function based many - body perturbation theory methods : gw and bse . here
, we perform a study where we compare the performance
of td - dft
using different xc potentials with correlated wave function methods
for a number of relevant nanoparticle structures , sampling a range
of titanium environments such as 3-fold , 4-fold , and 5-fold coordination .
we consider correlated wave function results obtained with the equation
of motion coupled cluster ( eom - cc ) methods and td - dft results
obtained with the pbe , b3lyp , cam - b3lyp , and bhlyp xc potentials .
we focus here on the performance of these methods when calculating
the vertical singlet excitation spectra of the nanoparticles , the
equivalent of the experimental uv vis absorption spectra .
we
pay special attention to the lowest singlet excitation ( s1 ) , as this
excitation , following kasha s principle , is the likely source of fluorescence ( luminescence ) and
the state relevant to applications such as photocatalysis and photovoltaics .
an accurate description of this state at the ground state geometry
is , therefore , a crucial staring point for future computational work
on tio2 nanoparticles that will focus on modeling phenomena
that involve excited state relaxation , following the ideas developed
by us and others . in this paper
, we will demonstrate that , for most of the tio2 nanoparticles , td - dft , with all the tested xc potentials
and eom - cc calculations give qualitatively similar results .
moreover ,
we will show that td - dft calculations , using the b3lyp and cam - b3lyp
xc potential , give the best quantitative fit to eom - cc excitation
energies .
importantly , however , we will also show that for an important
subset of structures td - dft can give qualitatively different results
depending on the xc potential used and that , in this case , only td - cam - b3lyp
and td - bhlyp calculations yield results that are qualitatively consistent
with those obtained using eom - cc theory
. we will demonstrate that
the discrepancies for these structures arise from a particular combination
of defects , excitation involving which are poorly described by td - pbe
and td - b3lyp .
finally , we demonstrate that these defects react exothermically
with water to form hydroxyl groups and show that for hydrated tio2 nanoparticles the qualitative discrepancies between the different
methods , observed for naked particles , disappear .
the geometry of each structure used
in this work was optimized
at the dft level with the hybrid b3lyp xc potential in conjunction with the triple- def2-tzvp basis
set .
the harmonic frequencies at the
geometries of the stationary points obtained in the dft optimizations
were calculated using the same dft setup ( b3lyp / def2-tzvp level ) to
verify that the optimized structures correspond to proper minima on
the ground state potential energy surface .
the electronic ground state
of all the clusters studied in this work is assumed to be a closed - shell
singlet .
for the naked ( tio2)n clusters , where n = 18 and 10 , we used
the global minimum ( gm , the lowest energy structure for a given cluster - size )
geometries reported by a number of groups , while for the clusters n = 9 and
1113 , we used the recent structures obtained by chen and dixon . to investigate a larger range of titanium and
oxygen coordination environments , we also examined a number of metastable
isomers ( i.e. , local minima for a given cluster size that lie higher
in energy than the gm ) .
for the ( tio2)2 dimer ,
this included two metastable structures that we labeled cis and club , with c2v and cs symmetry , respectively , while for the trimer ( tio2)3 we included one
higher metastable isomer with c1 symmetry ,
labeled as alt . the geometries of the stable and metastable
structures for the n = 15 subset are shown
in figure 1 , while the remaining n = 613 structures are given in section esi-1 of the supporting information .
global minimum ( gm ) atomic
configurations for ( tio2)n clusters
with n = 15 .
for the dimers and trimers , metastable clusters are also shown .
labels
include point group symmetry , and for the non - gm structures , the energy
difference in ev relative to the gm energy calculated at the b3lyp / def2-tzvp
level .
the hydrated systems ,
( tio2)n(h2o)m where n and m range from 1 to 3 , were obtained through
the saturation of all the under - coordinated titanium and oxygen atoms
present in the naked clusters with hydroxyl groups and protons , respectively .
here
, we assumed that titanium atoms are normally coordinated by at
least four oxygen atoms and oxygen atoms form at least two bonds .
the harmonic frequencies were also calculated on the dft optimized
geometries of each hydrated nanoparticle , in order to verify that
they correspond to proper minima .
the dft optimized structures include
ti(oh)4 , with s4 symmetry ;
( tio2)2(h2o)2 , with c2v symmetry ; and ( tio2)2(h2o ) , ( tio2)3(h2o)2 , and ( tio2)3(h2o)3 , all with c1 symmetry .
the coordinates of all the structures ( naked and hydrated ) used in
this study are listed in esi-1 and esi-3 , respectively .
( tio2)n(h2o)m hydrated clusters , with n and m ranging between 1 and 3 . in order to saturate
relevant defects ,
one water molecule is added per singly coordinated
oxygen atom in the originally naked clusters [ with the ( tio2)3(h2o)3 cluster as the only exception ,
where one additional water molecule was added to generate the same
coordination environment for all the titanium atoms ] . for each cluster
for all of the b3lyp optimized geometries , the
energies of the
lowest singlet excited states were obtained at the td - dft / def2-tzvp
level with different xc potentials ( the pure gga pbe , the hybrids b3lyp and bhlyp , and the range - separated hybrid xc potential cam - b3lyp ) . for
selected b3lyp optimized geometries , the
four lowest energy excited states were also calculated with two different
coupled cluster ( cc ) approaches : eom - ccsd and eom - ccsdt , methods already discussed in the context of tio2 clusters
in our previous work . due to
the
high computational cost required , we were not able to
optimize the structures of clusters larger than the monomer with the
cc approaches .
however , for some clusters , we have also obtained the
minimum energy geometries with the pbe and cam - b3lyp xc potentials
and calculated the respective vertical excitations .
the use of b3lyp
optimized structures , when compared to their fully optimized ground - state
counterparts for each different xc potential , was found to introduce
an average difference of 0.08 ev in the calculated excitation energies
for the smaller ( tio2)n naked
clusters , where n = 15 .
vertical excitations
at these optimized geometries are listed in the supporting information esi-2 . while for all td - dft calculations ,
we employed the def2-tzvp basis
set , in the case of the eom - cc methods , we used two different basis
sets : the split - valence def2-sv(p ) basis - set and the larger triple- def2-tzvpp basis set . from now on ,
these two basis sets will be referred to as
sv and tz , respectively .
all the coupled cluster calculations , for
reasons of computational tractability , employed the frozen core approximation
where only the valence electrons are correlated ( i.e. , the 1s orbitals
of the oxygen atoms and the 1s to 3p orbitals of the titanium atoms
are frozen ) .
our previous work showed ,
in the case of the tio2 monomer , that the use of the frozen
core approximation introduces a typical downward shift of 0.1 ev in
the calculated energy relative to the all - electron cc results .
the dft / td - dft calculations employing the pbe , b3lyp , and bhlyp
xc potential were performed with the turbomole 6.4 code , while the td - dft results obtained for the cam - b3lyp
xc potential were calculated with the gamess us code ( version 26 october
2012 ) .
the coupled cluster calculations
employed the tensor contraction engine ( tce ) module of the nwchem 6.1 package .
for the graphic representations of the
clusters studied , we used
the pymol molecular graphics system , while
vmd was employed for the visualization
of the differences between the ground state and excited state density .
in this section , we will first compare the
lowest excitation energies
of the ( tio2)n gm clusters
obtained with the four different td - dft xc potentials ( pbe , b3lyp ,
bhlyp , and cam - b3lyp ) .
we will then investigate how the choice of
the xc potential affects the shape of the td - dft optical spectrum ,
and in particular we compare the spectra of the ( tio2)n clusters that show different trends in their
excitations .
next , to further understand what is the origin of the
differences between excitation energies calculated with various xc
potentials , we investigate the excitation energies of a selection
of small clusters ( n = 15 ) with relevant
defects using eom - cc and compare the td - dft results ( td - b3lyp and
td - camb3lyp ) with the eom - cc benchmark values .
moreover , through the
calculation of the value we try to investigate the origin
of the trends shown by the different xc potentials , further confirming
the usefulness of this diagnostic test for the detection of possible
charge transfer ( ct ) problems in td - dft .
finally , we define some eom - cc
benchmarks for hydrated structures and try to understand if after
hydration the differences between the values predicted with the various
xc potentials still persist .
as shown
in figure 3 , the four different xc potentials
exhibit a similar
trend in the description of the lowest excitation energy ( s1 , the
absorption on - set ) for the ( tio2)n gm clusters .
there appears to be a constant energy shift that
is dependent upon the amount of exact hf - like exchange ( hfle ) included
in each of the xc potentials employed .
for example , pbe with 0% hfle
gives the lowest excitation energies , while bhlyp with 50% of hfle
yields the highest values .
excitation energies obtained using b3lyp
that has 20% hfle , and , cam - b3lyp , with 19% at short - range and 65%
at long - range , lie in between the pbe and bhlyp values .
however , aside
from the similarities observed among the four data series , it is easy
to see that the trend for td - pbe and td - b3lyp has two clear dips of
ca
. 0.5 ev , at ( tio2)3 and ( tio2)10 , which are absent in the cam - b3lyp and bhlyp results . in
addition , the pbe xc potential results show a similar but smaller
dip for the ( tio2)6 structure , while td - b3lyp
places this excitation in between the energies obtained for ( tio2)5 and ( tio2)7 , and td - cam - b3lyp
and td - bhlyp predict a local maximum in the trend for this geometry .
both of the lowest excitations for the ( tio2)3 and ( tio2)10 clusters correspond to states
with weak absorption intensity ( i.e. , low oscillator strength )
. however ,
it is important to stress that they are not dark states ( excitations
with zero absorption intensity ) ; with td - b3lyp the oscillator strengths
are 9 10 ( although 2 orders of magnitude
weaker than the most intense excitation among the hundred lowest excitations )
and 3.6 10 ( 1 order of magnitude weaker ) ,
respectively .
lowest singlet excitation energies calculated with different
td - dft
xc potentials for the b3lyp / def2-tzvp optimized ground state ( tio2)n gm structures .
pbe values are
represented by blue diamond markers , b3lyp red squares , camb3lyp green
circles , and bhlyp excitations are displayed as purple triangles . in agreement with the observations
above ,
figure s2.4 in section
esi-2 of the supporting information shows
that there is a good linear fit between the td - cam - b3lyp and td - bhlyp
predicted absorption on - set values of the gm clusters ( r of 0.99 , with r being the
coefficient of determination of the fit , which ranges between 0 and
1 ; as r approaches 1 , the quality of
the fit improves ) , while the correlation between td - cam - b3lyp and
td - b3lyp absorption on - sets is much weaker ( r of 0.80 ) .
not surprisingly , the clearest outliers in the
latter case are the absorption on - set values for ( tio2)3 and ( tio2)10 gm clusters .
we
also investigated the trends for the next two excited states
( the second and third lowest singlet excitations , s2 and s3 ) for the
same set of clusters ( see values and graph in esi-2 ) .
the trends found for these higher excited states are
very similar to the ones observed for the lowest excited state shown
in figure 3 .
the two dips for the ( tio2)3 and ( tio2)10 structures
are still there for the s2 and s3 states calculated with td - pbe and
td - b3lyp . the s2 and s3 states for ( tio2)3 exhibit
absorption intensities ( as calculated with td - b3lyp ) 1 order of magnitude
more intense than the lowest excitation , while for ( tio2)10 the s2 and s3 states have a weaker intensity compared
to the s1 state .
the underestimation of the excitation energies observed
when using pure gga xc potentials or hybrid xc potentials with a small
hfle contribution ( e.g. , b3lyp ) is thus not limited to the lowest
excited state , but it has an influence on higher energy states as
well and therefore on the overall shape of the optical spectrum . in
order to understand the size of this underestimation on the whole
spectrum , we compared the shape of the optical spectra calculated
with different xc potentials for the anomalous ( tio2)3 and ( tio2)10 clusters and the ( tio2)6 cluster as shown in figure 4a c ( for all of the xc potentials employed , only the
26 ev excitation range is shown ) .
td - dft calculated optical
spectra ( 100 lowest excitations , or 50
lowest in the case of td - cam - b3lyp for reasons of computational tractability )
for ( a ) ( tio2)3 gm , ( b ) ( tio2)6 gm , and ( c ) ( tio2)10 gm optimized structures
at the b3lyp / def2-tzvp level . in the top left of each spectrum , as
insert is shown , with a zoom in of the low - energy part of the spectrum .
the black line represents the td - pbe results , the red one the td - b3lyp ,
and the green one td - cam - b3lyp , while the blue one corresponds to
the td - bhlyp spectra .
all excitations plotted are represented as gaussians
with a standard deviation of 0.03 ev .
the different shapes of the spectra for ( tio2)3 emphasize the influence of the chosen xc potential .
td - pbe
and td - b3lyp
xc potentials predict a weak shoulder at low energies ( 1.97 and 2.96
ev , respectively ) , followed by an approximate 0.7 ev gap to the next
peak . in the case of td - cam - b3lyp and td - bhlyp ,
no such large gap
is observed , and the most intense peaks , for both of these xc potentials ,
seem to roughly agree after being rigidly shifted by ca .
0.5 ev . when
the td - b3lyp spectrum is shifted upward by ca . 1 ev and compared to
the td - cam - b3lyp spectrum
, we can clearly see that the two xc potentials
show a poor agreement in the lower energy range of the spectrum , with
b3lyp underestimating the first excitation energy and completely missing
the lower energy features predicted by td - cam - b3lyp .
the two xc potentials
show a much better agreement at higher energies , and although the
intensities do not match perfectly , all the peaks fall within the
same range of energies .
the td - b3lyp , td - cam - b3lyp , and td - bhlyp calculated
spectra for the n = 6 gm cluster , after a rigid shift
is applied , show a very good agreement on the position of the excitation
peaks . a suitable shift
could not be found in order to match the spectrum
generated using the pbe xc potential . finally , for the spectrum of
the ( tio2)10 structure shown in figure 4c , as expected , a similar behavior to the ( tio2)3 structure is observed . for example , the td - pbe
and td - b3lyp calculated spectra show a very weak shoulder at lower
energies , which , even after a rigid shift in energy , can not be made
to coincide with any of the peaks predicted by td - cam - b3lyp or td - bhlyp . as
observed in the previous section , the lowest energy excitation
for the two ( tio2)3 and ( tio2)10 structures is described differently depending on the xc
potential employed in the td - dft calculation . to benchmark the td - dft
results ,
, we confine our investigation to clusters
of a similar size to the ( tio2)3 cluster .
because
the gm ( tio2)3 cluster exhibits a three - coordinated
titanium atom and a three - coordinated oxygen atom , structural elements
not present in the other gm for n = 15 , we
also consider metastable clusters of two and three tio2 units reported in the literature , which have similar coordination
environments for titanium and/or oxygen atoms .
this led us to include
the so - called club structure , a ( tio2)2 isomer that is 0.73 ev ( b3lyp / def2-tzvp ) higher in energy
than the n = 2 gm and a trimer isomer that lies 0.32
ev higher than the n = 3 gm .
the latter has a three - coordinated
titanium atom , and in contrast with the trimer gm , no three - coordinated
oxygen atoms . for completeness
, we also compared td - dft and eom - cc
excitations for another ( tio2)2 isomer , which
is the cis version of the trans gm
and lies 0.25 ev ( b3lyp / def2-tzvp ) in energy above it .
all of these
structures are shown in figure 1 . in
figures 5 and 6 ,
the
four lowest excitation energies of the ( tio2)2 and ( tio2)3 global minima , respectively , are
plotted as a function of the chosen energy definition , td - dft ( b3lyp
and cam - b3lyp ) and different flavors of eom - cc : eom - ccsd / tz , eom - ccsd / sv ,
and eom - ccsdt / sv ( with the exception of eom - ccsd / tz excitation energies
for the ( tio2)3 gm cluster , eom - cc data were
taken from our previous work ) .
care should
be taken , when comparing absolute excitation energies , as the convergence
with respect to basis sets ( tz or better ) and cc excitation level
( eom - ccsdt or better ) are currently only numerically feasible for
the tio2 monomer , and even then supercomputing facilities
are required ( 4002000 cores per run with each core having
at least on the order of 2 gb of memory ) .
we thus focus instead primarily
on the relative ordering of the different excitations , exploiting
the fact that the clusters are highly symmetric and the excited states
thus span a number of different irreducible representations .
trend in the
four lowest excitation energies of the ( tio2)2 gm dimer cluster as calculated with different method
combinations ( 1bg red diamonds , 1au green squares , 1bu blue circles ,
and 2ag purple triangles ) .
sd and sdt stand
for eom - ccsd / t , while sv and tz correspond to the def2-svp and def2-tzvpp
basis sets .
all of the td - dft calculations ( b3lyp and cam - b3lyp ) employed
the def2-tzvp basis set .
all of the eom - cc data shown were taken from
our previous work .
the inset shows , for
all the methods employed , the difference between the higher excited
states ( e.g. , s4 , s3 , and s2 ) compared to the lowest excited energy
s1 .
trend in the five lowest excitation energies
of the ( tio2)3 gm trimer as calculated with
different method combinations
( 2a red diamond , 1a green
square , 3a blue triangle , 4a
purple circle , and 2a black diamond ) .
sd and sdt
stand for eom - ccsd / t , while sv and tz correspond to the def2-svp and
def2-tzvpp basis sets .
all of the td - dft calculations ( b3lyp and cam - b3lyp )
employed the def2-tzvp basis set .
all of the eom - cc data bar the eom - ccsd
tz ( sd tz ) excitation energies where taken from our previous work .
the
same energetic
ordering of the lowest excited states is observed for td - dft and the
different eom - cc flavors , with roughly similar energy differences
between the different excited states ( except that the gap between
the s2 and s3 excited state for td - b3lyp is much reduced ; this is
clearly shown in the inset of figure 5 , where
for each method we plotted the energy of the sx state against the
energy of the lowest excited state s1 ) .
the ( tio2)3 data in figure 6 paint , however , a
different picture , as there are a number of crossovers between the
lowest excited states .
we first compare the td - b3lyp and td - cam - b3lyp
results , which are , in line with the discussion above , very different .
not only is the energy difference between the s1 and s2 states reduced
from 0.6 ev for td - b3lyp to only 0.1 ev for td - cam - b3lyp , but the
next couple of excited states lies much closer in energy for td - b3lyp
than for td - cam - b3lyp .
some of the higher lying excited states effectively
become degenerate in the case of td - b3lyp and show a different ordering
than found with td - cam - b3lyp .
the td - cam - b3lyp and all eom - cc results ,
in contrast , are very similar ( with the exception of an interchange
between the close - lying s1/s2 states for both sets of eom - ccsd results ) . having compared the energies of different excited states of individual
clusters , we now compare the excitation energies between the ground
and lowest excited states for sets of clusters
again , we perform
calculations both with td - dft ( td - b3lyp and td - cam - b3lyp ) and eom - cc
methods ( eom - ccsdt / sv up to ( tio2)3 , eom - ccsd / tz
up to ( tio2)4 , and eom - ccsd / sv up to ( tio2)5 ) .
figure 7a contains
the td - dft results and figure 7b and c the
eom - ccsd / t tz and eom - ccsd / t sv data , respectively .
overall , td - dft
and eom - cc predict similar magnitudes of excitation energies as well
as a similar ordering of the lowest excited states of the different
clusters .
for example , all methods employed here predict the same
ordering of the lowest energy excitations of the dimer and monomer
( trans > cis > club
> monomer ) .
td - dft and eom - ccsd / sv also agree on where
the lowest
excitation energies of ( tio2)4 and ( tio2)5 global minima lie relative to that of the dimer .
however , for the ( tio2)3 gm cluster , the different
methods give widely different results . in agreement with eom - ccsd
,
td - cam - b3lyp predicts that the lowest excitation energy of the ( tio2)3 gm to be slightly higher than that for the ( tio2)2 gm .
in contrast , td - b3lyp places the ( tio2)3 gm lowest excitation in a similar energy range
as the lowest excitation of the ( tio2)2club isomer and below the alt trimer . eom - ccsd / tz
and eom - ccsd / sv predict that the lowest excitation energy of the ( tio2)3 gm lies slightly higher than that of the ( tio2)2 gm , while eom - ccsdt / sv puts the lowest excitation
energy of the ( tio2)3 gm slightly below that
of the ( tio2)2 gm . comparison of td - dft
excitation energies with eom - cc results for
a series of selected ( tio2)n clusters , with n = 15 . the global minima
( gm ) are represented by diamond markers , the metastable cis and club dimers by squares and triangles , respectively ,
and the metastable trimer ( alt ) by circles . ( a ) comparison
of td - camb3lyp ( green markers ) and td - b3lyp ( red ) excitations .
( b )
comparison between eom - ccsd and eom - ccsdt results with the high quality
tz basis set .
( c ) comparison between eom - ccsd and eom - ccsdt results
with the small sv basis set .
overall , both in terms of the relative energies of different
excitations
of the clusters and between different clusters , eom - cc calculations
suggest that td - dft does a reasonable job in describing electronic
excitations of tio2 clusters
. however , xc potentials with
no or low percentages of hfle , such as pbe and b3lyp , struggle for
specific structures .
td - cam - b3lyp ( and td - bhlyp ) , in contrast , yields
lowest excitation energies qualitatively consistent with eom - cc for
all structures studied . finally , when considering absolute excitation
energies , taking into account the caveats discussed above , those obtained
with td - cam - b3lyp lie generally quantitatively closest to the eom - cc
data .
we , therefore , would recommend using this xc potential , where
possible , to model excited state processes in tio2 nanoparticles .
it is well - known that the use of standard xc
potentials with no hfle ( i.e. , gga ) or a low percentage of hfle ( e.g. ,
b3lyp ) in td - dft can result in the underestimation of charge transfer
( ct ) excitations , where the origin and final destination of the excited
electron are separated spatially .
it is appealing to suppose that
this erroneous energetic stabilization of ct states might be the origin
of the discrepancy between td - pbe and td - b3lyp on one hand and td - cam - b3lyp ,
td - bhlyp , and eom - cc on the other hand .
hence , it is important to
try to characterize the ct character of the excitations for the different
nanoclusters , as calculated with td - dft . in this section ,
this diagnostic quantifies the spatial overlap
between the ( unperturbed ) occupied and virtual orbitals involved in
the td - dft excitation and hence is an estimate of the ct character
of a specific excitation .
the value corresponds to a dimensionless
number , which varies from 0 ( no overlap between the occupied and virtual
orbitals responsible for a td - dft excitation ) to 1 ( complete overlap
between the occupied and virtual orbitals ) . in the original
paper by peach
, it is suggested
that a td - dft excitation with small may be associated with
large ct errors , while in contrast small ct errors are associated
with large . in this fashion , the authors imply that , for example ,
td - pbe excitations with < 0.4 or td - b3lyp excitations with
< 0.3 are likely to contain a significant error , while
for td - cam - b3lyp no correlation is observed between errors and spatial
overlap , as measured by . these
limits , however , have been obtained for a set of organic molecules ,
and to our knowledge no one has yet published similar thresholds for
inorganic systems , e.g. , metal oxides .
figure 8 shows values calculated
with td - b3lyp for the three lowest excitations obtained for the n = 113 gm ( tio2)n clusters .
we calculated the values also for the pbe ,
cam - b3lyp , and bhlyp xc potentials for all the gms and the metastable
isomers , see the supporting information esi-2 . for the lowest excited state ( s1 , blue diamonds in figure 8) ,
all of the td - b3lyp values lie below the threshold
( 0.30 ) defined by peach et al . for hybrid xc potentials . however ,
among the values calculated for the s1 state using td - b3lyp ,
perhaps not surprisingly , both the ( tio2)3 and
( tio2)10 gm clusters are clearly the lowest ,
with some other clusters , ( tio2)7 , ( tio2)11 , and ( tio2)9 , showing
moderately low values as well . for the non - gm structures , the alt trimer has the lowest value .
values
for the higher excited states ( s2 and s3 ) , as shown in figure 8 , can be , depending on the particular cluster , both
larger and smaller than that of s1 .
examples of clusters with
values for higher excited states that lie below their s1 counterparts
include ( tio2)5 ( s2 ) , ( tio2)9 ( s2 ) , and ( tio2)13 ( s3 ) .
values
for the three lowest excited states ( lowest state
shown by blue diamonds , second lowest state by red squares , and third
lowest state by green circles ) of ( tio2)n clusters , with n = 113 , calculated
with b3lyp xc potential .
the dashed black line shows the threshold
defined by peach et al . for organic systems .
the data for our titania
clusters yield a number of interesting
observations .
first , all of the values for the tio2 clusters are smaller than typical values for organic systems ,
i.e. the tio2 clusters consistently have a smaller overlap
of the orbitals involved in the excitation .
we believe that this arises
from the fact that excitations in inorganic systems , such as tio2 , typically involve the displacement of an electron from one
sublattice ( using the term lattice loosely ) to another sublattice ,
here from orbitals based on oxygen atoms to those based on titanium
atoms .
in such a scenario , even local excitations ( i.e. , excitations
where both centers involved are spatially close ) might have low
values , especially if the material is rather ionic and there is thus
only limited overlap between orbitals on either sublattice .
the good
qualitative fit between the td - dft and eom - cc results for excitations
with values between 0.15 and 0.3 strongly suggests that these
are not excitations which are badly described by xc potentials due
to ct related problems .
a more interesting observation is that the
excitations for which the description is problematic with td - pbe and
td - b3lyp , both relative to that in td - cam - b3lyp and td - bhlyp and to
that by eom - cc , are the same excitations that have very low .
this observation suggests that the reason why the description of these
specific excitations is problematic within td - pbe and td - b3lyp is
that they have an especially strong ct character , and hence the states
involved are erroneously stabilized , i.e. , lie lower in energy relative
to the s0 ground state than they should .
for example , as outlined above , the second excitation ( s2 ) of the
( tio2)5 structure has a rather low value ,
substantially lower than that of s1 and s3 , and it is interesting
to compare in this context the predictions of td - b3lyp with those
obtained with other methods . the s2 excited state in td - b3lyp belongs
to the a irreducible representation ( just as s0 and s1 , and
hence it can be labeled as the 3a state ) , while
in eom - cc ( and in td - cam - b3lyp and td - bhlyp ) s2 belongs to the a
irreducible representation ( the 1a state ) and
s3 in contrast is the 3a state .
this swap in the
energetic ordering of the lowest two states is probably a direct result
of the erroneous ct related stabilization of the 3a
state in td - b3lyp , which shifts it below the 1a
state . a close inspection
of the atomic structures of the clusters studied , the orbitals involved
in the excitations and the ground state
excited state density
differences , suggests that the problematic ct excitations typically
involve one or more singly coordinated oxygen atoms as the origin
of the excited electron and hence the location of the formed hole .
the structural fragment on which the excited electron localizes varies
and can be , for instance , a titanium atom with nominally only three
oxygen atoms in its first coordination sphere ( as found for the ( tio2)3 gm and ( tio2)2club structures , see figure 9 ) or
a fragment constituted of three four - coordinated titanium atoms surrounding
a common three - coordinated oxygen atom ( as found for the ( tio2)10 gm structure , see figure 10 ) .
the latter combination of atoms is superficially similar
to that of one - half of the valence alternation pair ( vap ) defect - pair
in silica nanostructures .
the presence
of these structural fragments , however , is no guarantee that the lowest
excitations will have ct character .
this is illustrated , for example ,
by the case of the ( tio2)2club isomer ( see figure 9 ) .
this structure has
both a singly coordinated oxygen atom and a triply coordinated titanium
atom , but its lowest three excitations all have reasonable td - b3lyp
values ( see esi-2 ) , and their td - b3lyp excitation energies
qualitatively agree with eom - cc results .
td - b3lyp lowest singlet
excited state density difference and
value obtained for ( a ) the club dimer and ( b ) the
gm trimer . in both pictures , the green lobes represent regions of
excess electron density ( where the excited electron component of the
excited state is located , e ) , whereas the blue lobes represent regions deficient in electron
density ( where the hole component is found , h ) .
td - b3lyp lowest singlet
excited state density difference and
value obtained for the ( tio2)10 structure .
the
green lobes represent excess regions of electron density ( where the
excited electron component of the excited state is located , e ) , whereas the blue lobes
represent regions deficient in electron density ( where the hole is
found , h ) .
when rationalizing the above observations , we have to make
a choice
between a semi - ionic or a semicovalent reference frame . in the latter
reference , one can think of low - energy excitations as the transfer
of an electron between two well - defined centers that deviate electronically
and structurally from the bonding pattern in the remainder of the
particle ( e.g. , the silanone , si
o , nonbridging oxygens , si o * , and siloxy , si o centers
in silica ) .
in contrast , in the semi - ionic reference , the centres
involved in low - energy excitations are much less well - defined and
importantly much less obvious upon inspection .
the hole and electron
component of an excitation could be smeared out over a number of ions ,
with the precise ions involved ( i.e. , localization sites ) governed
by a subtle interplay between the on - site electrostatic potential
( the energetic cost of adding or removing an electron from a specific
ion ) and the electrostatic interaction between the excited electron
and the remaining hole ( i.e. , the exciton binding energy ) . intuitively ,
the latter picture seems closer to what we observe for ( tio2)n nanoparticles .
o distances in the clusters , and the fact that
the ti o distances for the singly coordinated oxygen atoms
are always virtually the same ( 1.6 ) , independent of the coordination
number of the nearest titanium atom , also suggests that the semi - ionic
reference frame is the most apt description of tio2 nanoparticles .
while in this picture , it is relatively difficult to link structure
to excitations , there is one important thing we can note . while singly
coordinated oxygen atoms have generally the lowest on - site electrostatic
( or madelung ) potential and are the centers from which an electron
gets removed if one does a single - point calculation for the cation ,
this does not mean , however , that it will be involved in the lowest
energy excitation ( or more generally in low energy excitations ) .
for
example , for ( tio2)4 the first two lowest excitations
do not involve the singly coordinated oxygen atoms , while for ( tio2)5 only the second excitation ( with td - b3lyp , see
discussion in section 3.3 and figure s-2.3
of the esi-2.5 ) involves the singly coordinated
oxygen atom .
the lowest excitation of the ( tio2)2club dimer , also , does not involve the singly coordinated
atom ( see figure 9 ) .
the hole and excited electron
in this case are localized in close proximity , maximizing excited
electron
hole overlap ( , see above ) and minimizing the
charge - transfer character of the excitation .
clearly , there is thus
a subtle balance between the on - site electrostatic potential and the
electrostatic interaction between electron and hole , where the latter
in practice is sufficiently strong to change which parts of the cluster
are involved in low energy excitations .
taking into account
the discussion above , it is likely that the
location of the excited electron and hole will change during excited
state processes that involve nuclear displacement ( e.g. , relaxation ) .
as a result , the electronic character of an excitation , its
value , and the ability of td - dft to correctly describe the excitation
might also change . in future work , we will , therefore , study this
explicitly . here , however , it is important to note that without a
correct description of the ( energetic ordering of the ) lowest excited
states at the ground state geometry , one has no hope of describing
what happens upon moving away from this starting point on the excited - state
energy landscape . upon hydration ,
all the centers discussed above
( i.e. , singly coordinated
oxygen atoms and under - coordinated titanium atoms ) are saturated by
the addition of hydroxyl groups ( oh ) and
protons ( h ) .
kj/(mol h2o ) in the case of ( tio2)2 , in line with previous estimates from the literature ) .
as structural and electronic features of the
naked systems are modified , so are the orbitals involved in the optical
excitation . in figure 11 , we present the comparison
between the td - b3lyp , td - cam - b3lyp , and eom - ccsd sv absorption on - set
for a series of hydrated ( tio2)n(h2o)m systems , where n and m range from 13 .
the addition
of water to the naked clusters results in a blue shift of their optical
spectra .
figure 11 also shows , in line with
that discussed above , how the cam - b3lyp excitations always lie at
higher energies than their b3lyp counterparts , with a mean difference
of 0.29 ev .
it is important to notice that , unlike what is observed
for specific naked structures ( e.g. , ( tio2)3 and ( tio2)10 ) , we found a generally good agreement
between b3lyp and cam - b3lyp excitations for all hydrated clusters .
in this case , the values computed for the b3lyp excitations
for the hydrated clusters are generally higher than those calculated
for the naked clusters ( values listed in the esi-4 ) .
moreover , the td - dft results with both xc potentials show a generally
good agreement with those obtained using eom - ccsd / sv , with an average
absolute difference of 0.27 ev for b3lyp and 0.20 ev for cam - b3lyp .
thus , hydration seems to effectively remove the centers responsible
for the problematic ct excitations and , more importantly , suggests
that td - b3lyp in general will give good results for hydrated systems .
comparison
between td - dft ( b3lyp , red markers and cam - b3lyp , green
markers ) lowest singlet excitations and eom - ccsd def2-sv(p ) ( blue
markers ) for hydrated ( tio2)n(h2o)m systems , where n and m range between 1 and 3 .
the diamond
markers represent the ti(oh)4 , ( tio2)2(h2o)2 , and ( tio2)3(h2o)2 structures , respectively ; the triangle marker ,
the ( tio2)2h2o cluster ; and the square ,
the ( tio2)3(h2o)3 cluster .
in this paper , we have studied the suitability of td - dft to describe
low - energy excitations in tio2 nanoparticles through a
comparison with eom - cc quantum chemistry calculations .
we find that
td - dft generally gives a good qualitative and also , in the case of
td - b3lyp and td - cam - b3lyp , a quantitative fit to excitation energies
predicted by the more accurate , but computationally much more expensive ,
eom - cc method .
however , for selected particles , e.g. , the ( tio2)3 gm cluster , we observe large deviations from
eom - cc results when using the td - pbe and td - b3lyp xc potentials .
calculation
of , which provides a measure of the orbital overlap between
the orbitals involved in the excitation , and visual inspection of
the excited - state density differences in these cases suggests that
problems arise for these systems when computing charge - transfer excitations ,
the energy of which relative to local excitations is underestimated
by td - pbe and td - b3lyp .
such problems are completely absent for td - cam - b3lyp
and td - bhlyp . on the basis of this and the overall good quantitative
fit of td - cam - b3lyp and eom - cc results ,
we recommend using this xc
potential , where possible , when studying excitations in tio2 nanoparticles .
finally , hydration of these particles removes the
structural centers responsible for the problematic charge - transfer
excitations , and all xc potentials studied here yield a good qualitative
fit to eom - cc results for hydrated particles . | we have investigated the suitability
of time - dependent density
functional theory ( td - dft ) to describe vertical low - energy excitations
in naked and hydrated titanium dioxide nanoparticles . specifically ,
we compared td - dft results obtained using different exchange - correlation
( xc ) potentials with those calculated using equation - of - motion coupled
cluster ( eom - cc ) quantum chemistry methods .
we demonstrate that td - dft
calculations with commonly used xc potentials ( e.g. , b3lyp ) and eom - cc
methods give qualitatively similar results for most tio2 nanoparticles investigated .
more importantly , however , we also show
that , for a significant subset of structures , td - dft gives qualitatively
different results depending upon the xc potential used and that only
td - cam - b3lyp and td - bhlyp calculations yield results that are consistent
with those obtained using eom - cc theory .
moreover , we demonstrate
that the discrepancies for such structures originate from a particular
combination of defects that give rise to charge - transfer excitations ,
which are poorly described by xc potentials that do not contain sufficient
hartree fock like exchange .
finally , we consider that such
defects are readily healed in the presence of ubiquitously present
water and that , as a result , the description of vertical low - energy
excitations for hydrated tio2 nanoparticles is nonproblematic . |
the importance of oral health in the early years of life is well documented , and advocated by professional and academic stakeholders worldwide.13 importantly , early childhood oral health influences and outcomes are considered pivotal in determining oral health trajectories across the life course , and can impact oral health and disease occurrence in adulthood.4,5 specifically , early childhood caries , the most common chronic childhood disease , is known to disproportionately affect vulnerable parts of the population and confer substantial impacts to children , families , and health systems.6 the list of possible sequelae of early childhood caries is long , and includes dental and medical consequences , pain , diminished quality of life , lost time ( children s from school and caregivers from work or other activities ) , increased expenditures , and others.7 despite significant strides in foundational sciences and the practice of clinical dentistry during the last few decades , the burden of childhood caries has persisted in most populations .
in fact , evidence indicates that oral health disparities may actually be on the increase.8,9 population - based strategies focused on prevention of oral disease are warranted to reduce these disparities .
moreover , efforts directed toward disease prevention are fundamentally superior to dental rehabilitation secondary to disease development when viewed from social justice , human rights , and health - promotion perspectives.10 nevertheless , common preventive protocols , such as the schedule and periodicity of routine dental visits , are not supported by a solid evidence base.11,12 similarly , uniform recommendations for early preventive dental visits ( epdvs ) for infants and children have been challenged with regard to the evidence base supporting their timing and benefit to different population groups.1315 various recommendations regarding the timing of children s first dental visit are available in the public domain , emanating predominantly from nonauthoritative sources.16,17 currently , major professional associations ( american academy of pediatric dentistry , european academy of pediatric dentistry , american dental association , canadian dental association , australian dental association , and american academy of pediatrics ) recommendations converge to the first dental visit taking place early , at the time of the first tooth eruption ( around age 6 months ) or by age 1 year.1821 despite these recommendations , the presence of visible caries lesions or dental trauma appear to impel most children s first dental visit.22,23 compounding this frequently problem - initiated pattern of care seeking , caregivers ability to recognize early signs of dental caries in very young children is limited.24 the current rationale for epdvs , above and beyond the delivery of such preventive services as fluoride treatment , includes the concepts of establishment of a dental home , anticipatory guidance , and risk assessment.15,18,25,26 because caregivers role is a major influence on their children s oral health behaviors and outcomes,5,27,28 epdvs offer an opportunity to educate caregivers of young children regarding optimal oral hygiene , feeding practices , and dental attendance , and prevention of early childhood caries and dental trauma.2934 nevertheless , evidence on the effectiveness of preventive dental visits from a young age in improving children s oral health outcomes is scarce .
to add to the knowledge base of epdvs , we carried out a comprehensive review of recommendations and published evidence regarding the benefits of epdvs .
accordingly , our aim was to systematically review and summarize current evidence regarding the effectiveness of epdvs in improving children s oral health outcomes .
we conducted a comprehensive literature search of pubmed and embase via elsevier electronic databases to identify relevant published studies .
the search strategy combined sets of terms covering three concepts : early preventive dental visits , outcomes , and infants or preschool children .
the following search was used in pubmed and modified for the embase via elsevier platform : ( dental[tw ] or dentist*[tw ] ) and ( visit*[tw ] or appointment*[tw ] ) and ( prevent*[tw ] or early[tw ] ) and ( quality of life[tw ] or absenteeism*[tw ] or outcome*[tw ] or utilization[tw ] or economics[subheading ] or cost[tw ] or costs[tw ] or expenditure*[tw ] or nonpreventive[tw ] or restorative[tw ] or emergenc*[tw ] or health behavior[mesh ] or oral hygiene[tw ] or decay[tw ] or caries[tw ] or dmft[tw ] ) and ( infant [ mesh ] or infant * [ tw ] or baby [ tw ] or babies [ tw ] or newborn [ tw ] or neonate * [ tw ] or child , preschool [ mesh ] or preschool child * [ tw ] or young child * [ tw ] ) .
gray literature , such as reports and conference proceedings , were excluded from embase search results .
the search was initially conducted in august 2013 , and was last updated on october 30 , 2013 . during the last update , our knowledge of the newly released study online by beil et al35 made us aware that the complexity of language used to describe young children might exclude retrieval of articles not yet indexed in pubmed .
as a result , we also searched using only the epdv part of the search and examined all the nonindexed articles for relevance . to aid in study identification , we developed inclusion and exclusion criteria ( table 1 ) based on the objective of this review , in the following categories : study population ( children age 06 years ) , type of dental services ( dental office - based oral evaluation and prevention services ) , and study outcomes ( oral health - related clinical , behavioral , or expenditure outcomes ) .
for this review , we excluded studies involving children with special health care needs and those published in languages other than english . first , the title and abstract were reviewed to determine potential relevance .
second , full texts of all potentially relevant articles were evaluated by two investigators ( vb and kd ) , and the articles meeting the inclusion and exclusion criteria were selected for this review .
finally , the following data from included studies were abstracted in a summary table : location , title , first author s name , type of study , study population , and outcomes , and overall findings independently by two investigators ( vb and kd ) .
although we did not intend a formal quality assessment of the included studies , we did critique their methodology and major findings , and where applicable , this is reported in the remarks column of the data - abstraction table .
our initial literature search identified 484 manuscripts in pubmed and 90 additional ones in embase , 45 of which were duplicates , creating a total database of 529 .
one additional potentially relevant nonindexed article was identified in pubmed during the search update , for a total of 530 .
after initial screening of titles and abstracts , as described in the materials and methods section , 24 manuscripts were selected for full - text evaluation . based on our inclusion and
exclusion criteria , four manuscripts were selected for inclusion in this review.3538 all four studies used a retrospective cohort study design and were carried out in the us ( table 2 ) . with the exception of the savage et al36 report , which was published in 2004 , the studies were published recently , in 20122013 .
all studies utilized public insurance ( medicaid , a us social health care program for families and individuals with low income and resources ) claims and had large sample sizes , ranging between 9,204 and 36,805 ( table 3 ) .
epdvs were defined using dental claims for preventive care ( comprehensive or recall examination , and preventive services including fluoride varnish and dental prophylaxis ) with few between - study variations .
three of the studies examined future preventive and nonpreventive dental visits and related expenditures as the primary outcomes.3638 importantly , in the most recent study , beil et al35 merged public insurance claim files with state kindergarten dental surveillance data , and thus this was the only study using a clinical end point ( dental caries , as measured by the decayed , missing , and filled teeth index ) as the study outcome . all investigations employed multivariate modeling methods to control for established sociodemographic confounding factors and study - design characteristics .
notably , sen et al38 implemented an additional econometric multivariate modeling strategy based on individual fixed effects , which according to the authors proved superior and more robust against the effects of selection bias compared to previously used
the beil et al35 study , among other comparisons , contrasted children who had their first preventive dental visit before versus after age 18 months and found no benefit of epdv in future clinically determined dental caries levels when children were examined in kindergarten .
savage et al36 found that children who had an epdv by age 1 year ( n=23 , or 0.24% of the study sample ) were more likely to have future preventive dental visits and were equally likely to have future restorative or emergency ones versus children who had a preventive visit at a later age .
these authors also reported a positive association between the age of the first dental visit and future dental - related medicaid expenditures .
in contrast , beil et al37 did not find any difference in subsequent dental outcomes between children who had primary or secondary prevention services by the age of 18 months and those that received services at an older age .
these authors highlighted the possible issues of selection bias and problem - driven dental care - seeking patterns in this type of dental care - service research study .
finally , in the beil et al35 report , the authors found that preventive dental visits were associated with significant reductions in children s subsequent nonpreventive dental visits and related expenditures , appearing to benefit their oral health .
however , they reported that preventive visits were associated with an overall increase in the program s expenditures during the study period .
in this paper , we sought to critically and comprehensively evaluate the evidence base of the effectiveness of epdvs in improving children s oral health , and found limited evidence in that direction .
the only study that considered a clinical end point by investigating dental caries levels at kindergarten did not find any effect of epdvs .
nevertheless , earlier preventive dental visits appear to be associated with more future preventive visits .
data on epdvs effects on subsequent dental treatment ( nonpreventive ) visits and related costs from three studies are mixed ; however , the largest study to date reported an association of epdvs with fewer future nonpreventive dental visits and lower nonpreventive dental expenditures .
while these data provide partial support for epdvs and the year 1 dental visit , particularly for children at high risk or with existing dental disease , more studies among diverse populations are warranted to add to the evidence base .
the fact that to date there are insufficient data to conclusively support the human and economic benefits of epdvs for all children does not imply that these benefits do not exist .
there is ample theoretical and philosophical support for the benefits of health promotion and primary prevention over disease management and treatment,3941 while epdvs are consistent with the establishment of a
dental home.25,26,29 the latter is philosophically aligned to the american academy of pediatrics concept of a medical home , where comprehensive pediatric primary care is provided contiguously , in a setting where provider and families should be able to develop a relationship of mutual responsibility and trust.42 ideally , the establishment of a dental home should take place at a time when provision of anticipatory guidance to caregivers and application of preventive modalities to children can have a true primary preventive effect , prior to the occurrence of disease or traumatic injury .
the establishment of a dental home may be especially important for children of caregivers with low health literacy28 or socioeconomic disadvantage,43,44 and generally those at high risk for dental disease.45 earlier preventive dental visits were associated with more subsequent preventive visits in both the savage et al36 and sen et al38 studies , with the total program oral health - related expenditures being positively associated with epdvs in the latter .
the observation that prevention costs may not result in immediate program savings is , to some degree , expected.46 first , long - term benefits of epdvs may not be discernible in the 2- to 5-year observation windows of the reviewed studies .
second , possible positive effects on oral health behaviors , wellness , quality of life , pain , and lost time averted due to restorative treatment needs are not easily quantifiable and can not be readily juxtaposed to dollar expenditures .
however , this also offers an opportunity for the conduct of future studies examining the effects of epdvs using additional oral health - related outcomes , such as caregivers oral health knowledge and behaviors , and children s oral health - related quality of life . despite current professional recommendations for the year 1 dental visit ,
first , information available to caregivers ( ie , freely available online ) regarding their children s first dental visit is not always in agreement with the professional recommendations.16,17 as most authors noted , patterns of dental care seeking for very young children appear to be problem - initiated rather than driven by primary prevention .
moreover , it is well documented that shortages in the dental workforce ( general and pediatric dentists ) pose a barrier to access to care for large portions of the population , particularly those enrolled in public insurance and residing in rural areas.47,48 in an environment with limited resources , it appears reasonable to support a need- and risk - based prioritization of epdvs,35,37 as low - risk groups may benefit the least from early dental office - based visits.49 on the other hand , the task of determining clinical treatment needs and caries risk without an epdv remains a challenge , because the actual oral health trajectory of individual children is otherwise unobservable . in this regard , the potential role of nondental providers in screening all young children and referring those at high risk and with treatment is crucial .
this model has been successfully implemented in north carolina , as the into the mouths of babes program,50 resulting in improvement of oral health care - services utilization51 and reductions of dental caries - related treatments among preschool children.52 although econometric evaluations of the program did not reveal any cost savings,53,54 this model offers an excellent avenue for the delivery of preventive oral health services ( ie , fluoride varnish application ) and the conduct of oral health screenings and referrals for specialist care .
these services are not offered in a dental setting ; however , these visits can be considered epdvs and further research on their effectiveness in improving children s oral health outcomes is warranted .
the currently available evidence base supporting the effectiveness of epdvs and the year 1 first dental visit recommendation is weak , and more research among diverse populations is warranted . despite the strong theoretical and philosophical support for benjamin franklin s an ounce of prevention is better than a pound of cure , evidence to date has shown benefits of preventive dental visits before age 3 years only among children at high risk or with existing dental disease .
nevertheless , epdvs are associated with more subsequent preventive dental visits , and may be associated with reduced restorative dental care visits and related expenditures during the first years of life . | backgrounddental caries , the most common childhood chronic disease , disproportionately affects vulnerable parts of the population and confers substantial impacts to children , families , and health systems . because efforts directed toward oral health promotion and disease prevention
are fundamentally superior to dental rehabilitation secondary to disease development , early preventive dental visits ( epdvs ) are widely advocated by professional and academic stakeholders .
the aim of this comprehensive review was to critically review and summarize available evidence regarding the effectiveness of epdvs in improving children s oral health outcomes.materials and methodsa systematic literature search of the pubmed and embase electronic databases was undertaken to identify peer - reviewed publications investigating the effectiveness of epdvs on oral health outcomes , including clinical , behavioral , and cost end points up to october 30 , 2013 .
outcomes of the identified studies were abstracted and summarized independently by two investigators.resultsfour manuscripts met the inclusion criteria and were included in the review .
all studies were conducted in the us and employed a retrospective cohort study design using public insurance - claims data , whereas one study matched claims files with kindergarten state dental surveillance data .
that study found no benefit of epdvs in future clinically determined dental caries levels in kindergarten .
the other three studies found mixed support for an association of epdvs with subsequent more preventive and fewer nonpreventive visits and lower nonpreventive service - related expenditures .
selection bias and a problem - driven dental care - seeking pattern were frequently articulated themes in the reviewed studies.conclusionthe currently available evidence base supporting the effectiveness of epdvs and the year 1 first dental visit recommendation is weak , and more research is warranted .
the benefits of epdvs before the age of 3 years are evident among children at high risk or with existing dental disease .
however , epdvs may be associated with reduced restorative dental care visits and related expenditures during the first years of life . |
hypertension is a complex syndrome influenced by multiple genetic and environmental factors . in view of some individuals being more susceptible to hypertension than others ,
although great hope was expressed in genome - wide association studies to unlock the genetic basis of hypertension , the results from such research , however , have told us little . given the limited power of single studies , one practicable strategy is to perform large meta - analyses to reliably evaluate the predetermined candidates in genetic association studies .
the gene encoding atrial natriuretic peptide ( anp , chromosome 1p36.21 ) is a logical candidate for involvement in the underlying cause of hypertension .
knockout mice deficient in one copy of anp gene was associated with salt - sensitive hypertension .
in contrast , overexpression of anp gene via gene therapy in hypertensive mice had lowered systolic blood pressure .
these findings therefore encourage the search for human genetic polymorphisms that affect the anp functionality .
a large panel of anp gene polymorphisms have been identified ; in particular , an exonic polymorphism t2238c ( rs5065 ) ranks high in association with hypertension ; however , the results in some individually underpowered studies are often irreproducible [ 6 , 7 ] . to derive a more precise estimation ,
we therefore meta - analyzed the association of anp gene t2238c polymorphism with occurrence of hypertension from both english and chinese literature , while addressing between - study heterogeneity and publication bias .
we searched pubmed and embase , as well as china biological medicine ( http://sinomed.imicams.ac.cn/index.jsp ) and wanfang ( http://www.wanfangdata.com.cn ) databases for articles published before 10 february 2011 using the boolean combinations of keywords ( atrial natriuretic peptide or natriuretic peptide precursor a or anp or nppa ) and ( hypertension or blood pressure ) and ( polymorphism or allele or genotype or variant or variation ) .
search results were limited to human populations and articles written in both english and chinese languages .
the full text of the retrieved articles was scrutinized to decide whether information on the topic of interest was included .
reference lists of these retrieved articles and systematic reviews were also checked to determine whether citations of articles were not initially identified .
for these articles involving more than one geographic or ethnic heterogeneous groups , each group was treated separately .
articles were included in this meta - analysis if they examined the hypothesis that anp gene t2238c polymorphism was associated with hypertension , if they followed a case - control or cross - sectional study design , and if they provided sufficient information on t2238c genotype counts between hypertensive patients and controls for determining an estimate of odds ratio ( or ) and its corresponding 95% confidence interval ( ci ) .
hypertension was defined as systolic blood pressure equal to or above 140 mmhg or diastolic blood pressure equal to or above 90 mmhg or previous treatment with antihypertensive drugs .
studies evaluating secondary hypertension or other types of monogenic hypertension were excluded . where there were multiple articles from the same study population ,
the following characteristics were extracted independently and entered into separate databases by wenquan niu and yue qi ( who is an assistant researcher in beijing institute of heart , lung & blood vessel diseases , anzhen hospital ) from each qualified study : first author 's last name , publication date , population ethnicity , study design , diagnostic criteria , baseline characteristics of the study population ( such as age , gender , and body mass index ) , and the t2238c genotype counts in patients and controls . for consistency , quantitative variables expressed as
mean standard error ( se ) were converted to mean standard deviation ( sd ) .
any encountered discrepancies were adjudicated by a discussion , and a consensus was reached .
the random - effects model using the dersimonian & laird method was implemented to bring the individual effect - size estimates together , and the estimate of heterogeneity was taken from the mantel - haenszel model .
unadjusted or and 95% ci were used to compare genetic contrasts between patients and controls . between - study
heterogeneity was assessed by the inconsistency index i statistic ( ranging from 0 to 100% ) , which was documented for the percentage of the observed between - study variability due to heterogeneity rather than chance , with higher values suggesting the existence of heterogeneity [ 14 , 15 ] . in the case of between - study heterogeneity , we examined the study characteristics that can stratify the studies into subgroups with homogeneous effects .
in addition , to estimate the extent to which one or more covariates explain heterogeneity , meta - regression , as an extension to random - effects meta - analysis , was employed .
cumulative meta - analysis was conducted to identify the influence of the first published study on the subsequent publications , and the evolution of the combined estimates over time according to the ascending date of publication . to identify potentially influential studies ,
sensitivity analysis was undertaken by removing an individual study each time to check whether any of these estimates can bias the overall estimate .
egger 's test can detect funnel plot asymmetry by determining whether the intercept deviates significantly from zero in a regression of the standardized effect estimates against their precision .
probability less than 0.05 was judged significant with the exception of the i statistic and egger 's test , where a significance level of less than 0.1 was chosen .
based on our search strategy , the primary screening produced 25 potentially relevant articles , of which 7 met the inclusion criteria with an attempt to evaluate the association of anp gene t2238c polymorphism with the occurrence of hypertension [ 612 ] .
of these 7 articles , three [ 68 ] were published in english and four in chinese language [ 912 ] .
five out of 7 articles were conducted in asians ( four in chinese [ 912 ] and one in japanese ) .
overall 2238c allele frequency was 4.19% in patients and 8.14% in controls with the highest frequency noted in an african - american population ( 41.67% and 38.64% ) and the lowest frequency in a chinese han population ( 0.92% and 0.82% ) .
genotyping for t2238c polymorphism across all studies , except two using the gene chip technology [ 9 , 12 ] and one using taqman assay , was conducted using polymerase chain reaction - restriction fragment length polymorphism ( pcr - rflp ) followed by enzyme scai digestion .
considering the low frequency of 2238cc genotype , we only assessed the association of 2238c allele ( relative to 2238 t allele ) with hypertension risk in this meta - analysis . overall speaking ,
comparison of allele 2238c with 2238 t generated a 23% reduced , albeit nonsignificant , risk for hypertension ( 95% ci : 0.381.59 ; p = .485 ) ( figure 2 ) .
meanwhile , there was strong evidence of between - study heterogeneity ( i = 88.3% , p < .0005 ) and high possibility of publication bias as reflected by the suggestive asymmetry of funnel plot ( figure 3 ) and the egger 's test ( p = .051 ) . in the cumulative meta - analysis , there was no evidence suggesting the first published study that reported a potentially significant result and then trigged the subsequent replication ( data not shown ) . however , the influential analysis revealed that there was one study in a kazakh chinese population influencing the overall results significantly ( figure 2 ) . when this most influential study was removed , the overall estimate was strongly attenuated with or approaching the unity ( or = 0.97 ; 95% ci : 0.621.51 ; p = .897 ) .
likewise , between - study heterogeneity was remarkably reduced ( i = 51.2% , p = .069 ) , and there was a low probability of publication bias ( p = .479 ) ( figure 3 ) . considering the significance of heterogeneity , we considered as a better choice to try investigating its sources by conducting subgroup analysis in characteristic - homogeneous groups . to evaluate the possible effect of study design on the variability of overall estimates ,
studies were divided into population - based and hospital - based studies , and importantly the magnitude of association in population - based studies was strikingly reinforced with the 2238c allele conferring a significant protective effect on hypertension ( or = 0.33 ; 95% ci : 0.130.80 ; p = .015 ) , whereas this effect was reversed in hospital - based studies with no attainable significance ( or = 1.15 ; 95% ci : 0.791.68 ; p = .454 ) ( figure 4(a ) ) .
further subgroup analysis by ethnicity suggested heterogeneous associations of t2238c polymorphism with hypertension , by showing a suggestive risk effect of 2238c allele in blacks ( or = 1.13 ; p = .66 ) , a significant protective effect in whites ( or = 0.53 ; p = .019 ) , and a moderate protective effect in asians ( or = 0.79 ; p = .663 ) ( figure 4(b ) ) .
because sample size of study is also a major factor affecting the reliability , we therefore used an additional strategy to estimate the effect by grouping only those large association studies with an arbitrary cutoff of 500 individuals .
two out of seven studies had sample sizes greater than 500 and conferred a 53% reduced risk for 2238c allele relative to 2238 t allele ( 95% ci : 0.092.45 ; p = .374 ) , accompanying high between - study heterogeneity ( i = 94.7% , p < .0005 ) ( figure 4(c ) ) .
to further account for between - study heterogeneity within a multivariable framework , we performed meta - regression by incorporating various study - level covariates including averaged levels of age , male percent , and body mass index ( bmi ) between patients and controls , as well as study design and ethnicity altogether , and we interestingly and exclusively observed that study design was a significant source of between - study heterogeneity ( p = .042 ) .
this study , including 4068 subjects , to our knowledge , is the first meta - analysis examining the relationship between anp gene t2238c polymorphism and hypertension .
although some statistical biases could not be eliminated , our results suggested that carriers of 2238c allele were at moderate decreased risk of developing hypertension , whereas study design was identified as a potentially significant source of between - study heterogeneity by both subgroup and meta - regression analyses , indicating the robustness of our results .
genetic heterogeneity is an inevitable problem in any disease identification strategy . as shown in this study
, we speculated that anp gene t2238c polymorphism might have diverse roles in different ethnic populations .
on one hand , striking differences were noted in terms of mutant 2238c allele frequency between african - americans and asians , with the former almost tenfold higher than the latter , suggesting that different genetic backgrounds may cause this discrepancy , or different populations may have different linkage disequilibrium patterns .
a polymorphism may be in close linkage with another nearby causal variant in one ethnic population but not in another .
the anp gene t2238c polymorphism may be in close linkage with different nearby causal variants in different populations .
on the other hand , in our subgroup analysis , t2238c polymorphism showed significant heterogeneous associations with hypertension across different ethnic groups , with 2238c allele in african - americans being completely at odds with that in whites and asians , suggesting that this polymorphism might have a multifunctional role in the pathogenesis of hypertension or interact with other genetic and environmental factors .
however , considering the relative small sample sizes in each group , we suggest that confirmation in large , well - designed studies is critical . besides the disturbing influence of ethnicity in this meta - analysis
interestingly , we observed that magnitude of association was reversed in population - based studies relative to in hospital - based studies although no significance was identified for the latter .
regarding this point , we agree that control for population stratification remains an important consideration in hospital - based studies , because in this meta - analysis , most studies have recruited subjects from only one hospital , and thus there might be a narrow socioeconomic profile for both patients and controls . moreover , in hospital - based studies , poor comparability between cases and controls might exert a confounding effect on the true association in light of a regional specialty for the disease under study and the differential hospitalization rates between cases and controls .
in contrast , subjects drawn from community or a fixed group might be representative of the true population , leading us to believe that results from population - based studies might hold the water . considering the wider confidence intervals of estimates and small sample sizes in population - based studies , more studies are required to quantify this effect size reliably . despite the clear strengths of our study including relatively large sample sizes and robustness of statistical analyses , interpretation of our current study , however , should be viewed in light of several technical limitations .
because only published studies were retrieved in this meta - analysis and the grey literature ( articles in languages other than english and chinese ) was not included , publication bias might be possible , even though our funnel plots and statistical tests did not show it .
in addition , most studies in this meta - analysis have recruited subjects aged 50 years , for whom environmental factors are likely to contribute more prominently than the genetic component to the development of hypertension , suggesting that large association studies in a younger population of hypertensive subjects are of added interest . moreover , the single - locus - based nature of meta - analysis precluded the possibility of gene - gene and gene - environment interactions , as well as haplotype - based effects , suggesting that additional studies assessing these aspects will be necessary .
furthermore , we only centered on anp gene t2238c polymorphism and did not cover other candidate genes or polymorphisms .
it seems likely that the t2238c polymorphism individually makes a moderate contribution to risk prediction in hypertensive subjects , but whether this polymorphism integrated with other risk factors will enhance the prediction requires additional research .
thus , the jury must refrain from drawing a conclusion until large , well - performed studies confirm or refuse our results . taken together , we expand previous single studies on hypertension by suggesting that anp gene t2238c polymorphism might contribute to the occurrence of hypertension , especially in population - based studies . also our observations leave open the question regarding the heterogeneous effect of 2238c allele across different ethnic populations .
further genetic and functional studies are warranted to elucidate the relationship between t2238c polymorphism and hypertension , and mechanisms of the anp gene and hypertension . | single studies attempting to associate anp gene t2238c ( rs5065 ) polymorphism with hypertension have so far reported inconclusive results .
we therefore aimed to evaluate this association via a meta - analysis .
data on 7 studies with a total of 4068 subjects were available and analyzed using the random - effects model with assessment of heterogeneity and publication bias .
overall comparison of 2238c with 2238 t yielded a 23% reduced , albeit nonsignificant , risk for hypertension ( 95% ci : 0.381.59 ; p = .485 ) , while accompanying significant heterogeneity ( i2 = 88.3% ) and publication bias ( p = .051 ) .
subgroup analysis by study design demonstrated opposite associations between population - based ( or = 0.33 ; 95% ci : 0.130.80 ; p = .015 ) and hospital - based studies ( or = 1.15 ; 95% ci : 0.791.68 ; p = .454 ) .
further meta - regression analysis exclusively indicated the significant influence of study design ( p = .042 ) on heterogeneity . taken together , these findings support the notion that carriers of 2238c allele were at moderate decreased risk of developing hypertension , whereas study design was identified as a potentially significant source of between - study heterogeneity . |
influenza viruses were isolated in madin - darby canine kidney cells from lung tissue or nasal swab samples from pigs of various ages ( young growers to adults ) manifesting influenzalike illness ( ili ) in manitoba in january ( a / swine / manitoba/12707/05 ) , alberta in february ( a / swine / alberta/14722/05 ) , british columbia in may ( a / swine / british columbia/28103/05 ) , and ontario in july ( a / swine / ontario/33853/05 ) .
a / ontario / rv1273/05 was isolated in primary rhesus monkey kidney cells from a nasal swab specimen collected as part of a diagnostic workup from an otherwise healthy farm worker in ontario in whom ili developed 23 days after onset of ili among pigs on his premises .
fourteen - day courses of oseltamivir therapy were prescribed for this patient beginning the day he saw his physician and for 11 other potentially exposed farm workers beginning 2 days later .
a / turkey / ontario/31232/05 was isolated in embryonated hen 's eggs from a cloacal swab sample from turkeys showing a severe drop in egg production .
the turkey farm was located across the road from a swine farm at which pigs concurrently exhibited ili , although virus isolates were not available from those pigs .
nucleotide sequences of the full - length coding regions of all 8 rna segments from each virus were determined by direct cycle sequencing with previously described techniques and primers ( 3,10,11 ) .
related reference viruses were identified by blast ( basic local alignment search tool ) analyses , sequence comparisons were conducted by using dnastar software , version 6.3 ( dnastar inc . , madison , wi , usa ) , and phylogenetic relationships were estimated from the nucleotide sequences by the method of maximum parsimony ( fast heuristic search algorithm , paup software , version 4.0b10 [ sinauer associates , inc . , sunderland , ma , usa ] ) with a bootstrap resampling method ( 200 replications ) .
pairwise nucleotide identities among the 2005 canadian swine , turkey , and human isolates range from 94.0%100% ( na ) to 99.9%100% ( m ) , and amino acid identities range from 98.9%100% ( na ) to 100% ( m , np ) .
the human and swine isolates recovered on a single farm in ontario are 100% identical in nucleotide sequences across all 8 rna segments .
phylogenetically , the 2005 canadian viruses form single clusters on phylograms for each of the 8 viral rna segments , confirming that this epizootic was caused by a single lineage of viruses .
all of the viruses share the same human / classical swine / avian triple reassortant genotype as the h3n2 viruses that emerged in pigs in the united states in 1998 ( 24 ) .
the ha genes ( figure 1 ) of the canadian viruses are most closely related to the cluster iii group of american viruses that were first isolated from pigs in 1999 ( 4 ) and subsequently from turkeys ( 7,8 ) , though the ha phylogram topography suggests that these canadian and related us viruses represent a new , separate cluster ( iv ) of viruses .
the m , np , ns , and polymerase genes of the canadian viruses are also phylogenetically closely related to reassortant viruses dating back to 1998 in the united states ( data not shown ) .
in contrast , the na genes ( figure 2 ) of the 2005 canadian viruses , though still clearly of human lineage , are phylogenetically distinct from most of the us swine and turkey isolates . this lineage
is represented by human h3n2 isolates from asuncin , paraguay , ( 2001 ) and new york ( 2003 ) .
however , this lineage of na genes has also been introduced into animal influenza viruses on 2 previous occasions .
the first is represented by a / turkey / ohio/313053/04 ( 8) , which phylogenetically is the most closely related virus to the canadian viruses across all 8 rna segments . since this virus was isolated in february 2004 ( 8) , nearly 1 year before the first isolations of viruses from canada , one might conjecture that this or a closely related virus from the united states was the source of the canadian viruses .
however , this lineage of na genes was also already present in human / classical swine reassortant h1n2 viruses ( a / swine / ontario/48235/04 , a / swine / ontario/55383/04 ) isolated from canadian pigs in 2004 ( 12 ) .
thus , it is neither possible nor prudent from the phylogenetic data alone to define the specific epidemiologic source(s ) of the 2005 canadian h3n2 viruses .
however , the appearance of this lineage of na genes among h3n2 viruses in turkeys in the united states and canada and h3n2 and h1n2 viruses in pigs in canada suggests that a complicated web of interspecies transmission , reassortment , and transboundary movement of viruses occurred in a relatively short period of time .
nucleotide phylogram for the hemagglutinin ( ha ) genes of a / swine / manitoba/12707/05 , a / swine / alberta/14722/05 , a / swine / british columbia/28103/05 , a / swine / ontario/33853/05 , a / turkey / ontario/31232/05 , a / ontario / rv1273/05 , and related reference viruses .
the evolutionary relationships among these viruses were estimated by the method of maximum parsimony ( paup software , version 4.0b10 ) with a bootstrap resampling method ( 200 replications ) and a fast heuristic search algorithm .
horizontal - line distances are proportional to the minimum numbers of nucleotide changes needed to join nodes and gene sequences .
the designations i , ii , and iii identify clusters of viruses previously defined among triple reassortant swine viruses in the united states ( 4 ) .
the viruses described in this report and related viruses are proposed to represent a new cluster iv group of viruses .
genbank accession numbers for the sequences of all reference viruses are provided in parentheses after the virus names .
nucleotide phylogram for the neuraminidase ( na ) genes of a / swine / manitoba/12707/05 , a / swine / alberta/14722/05 , a / swine / british columbia/28103/05 , a / swine / ontario/33853/05 , a / turkey / ontario/31232/05 , a / ontario / rv1273/05 , and related reference viruses .
the evolutionary relationships among these viruses were estimated by the method of maximum parsimony ( paup software , version 4.0b10 ) with a bootstrap resampling method ( 200 replications ) and a fast heuristic search algorithm .
horizontal - line distances are proportional to the minimum numbers of nucleotide changes needed to join nodes and gene sequences .
genbank accession numbers for the sequences of all reference viruses are provided in parentheses after the virus names .
to our knowledge , this report describes the first isolation of a human / classical swine / avian triple reassortant h3n2 virus from a human .
this isolation could not have occurred through cross - contamination in a laboratory since the animal and human virus isolations and sequencing were conducted in different locations .
hemagglutination - inhibition ( hi ) and virus neutralization ( vn ) assays of acute- and convalescent - phase ( 11 and 45 days after the acute - phase sample ) sera did not show evidence of seroconversion against the patient 's own isolate , a / ontario / rv1273/05 ( hi titer = 8 and vn titer = 16 on all 3 test dates ) .
thus , although this farm worker had a febrile respiratory illness and no other etiologic agent was identified , we can not prove that he was actively infected with the triple reassortant virus ; he may have simply been harboring the virus in his nasal passages .
nonetheless , this isolation shows that agricultural workers may be exposed to influenza viruses from livestock . in summary
, this report describes the emergence and rapid spread since january 2005 of reassortant h3n2 influenza a viruses among pigs and turkeys across canada and isolation of a related virus from the nasal passages of a farm worker in ontario .
the 4 swine isolates chosen for our analyses provide a sampling of viruses from british columbia to ontario , but clinical reports indicate that the outbreak of ili in pigs was much more extensive than this limited number of isolates might suggest . for example , h3n2 virus infections were confirmed on 22 swine farms in ontario between late april and early july 2005 . likewise , additional infections of turkeys with h3 viruses in 2005 were reported in british columbia ( on a farm that was near a swine farm where h3 virus was detected ) and in multiple flocks in manitoba ( a. hamel and g. nayar , pers .
when this canadian epizootic is considered together with the extensive spread of genotypically similar h3n2 and h1n2 viruses in pigs and turkeys seen in the united states since 1998 , we see that viruses with this human / classical swine / avian triple reassortant genotype can efficiently infect both pigs and turkeys .
the genbank numbers assigned to the gene sequences of viruses investigated in this study are as follows : a / ontario / rv1273/05 , dq469955dq469962 ; a / swine / alberta/14722/05 , dq469963dq469970 ; a / swine / british columbia/28103/05 , dq469971dq469978 ; a / swine / manitoba/12707/05 , dq469979dq469986 ; a / swine / ontario/33853/05 , dq469987dq469994 ; and a / turkey / ontario/31232/05 , dq469995dq470002 . | since january 2005 , h3n2 influenza viruses have been isolated from pigs and turkeys throughout canada and from a swine farmer and pigs on the same farm in ontario .
these are human / classical swine / avian reassortants similar to viruses that emerged in us pigs in 1998 but with a distinct human - lineage neuraminidase gene . |
competency is defined as the essential ability to perform a procedure safely and successfully without supervision . for a qualified dentist , competency is the summary of knowledge , attitude , professionalism , critical thinking and problem - solving skills , ethical values , and technical and procedural skills .
the universidad peruana cayetano heredi , faculty of stomatology ( lima , peru ) was the first to address the issues of competencies .
an exercise to evaluate the content and structure of its curriculum by assessment of the dental practice of their students was carried out . as a result ,
a new term called competency - based dental curricula was developed and then distributed internationally to the educational and scientific world . given that , a competency in public health dentistry is designed by the interface between the community health care requirements and the provided dental treatments .
this interaction has impacted the curricular design in a two - mode matrix . to establish competent skills to handle periodontal disease , for example , a disease of oral tissues , student need to perform all related functions regarding diagnosis , promotion , prevention , treatment , rehabilitation , and administration .
there are twelve competencies in our terminology and ranked second in complexity scale . similarly , the competency of public health dentistry has six types of patient care delivered by a qualified dentists to tackle the community needs of oral health care primarily . testing the competencies of student 's performance
is an essential step to ensure safeguarding practices , maintaining accreditation certificates , and ultimately evaluating the curriculum and revising accordingly .
survey - based questionnaire is a standard method for measuring the competency of freshly qualified dentists to define their apparent expertise in particular areas of dentistry .
however , the scope of these studies focused on assessing the competency of the practical procedures of the profession rather than addressing the competencies of public health dentistry .
this paper aimed to examine the level of self - perceived proficiency in the dental public health of dentists at the time of their graduation .
specifically , the objectives of this article were :
to compare the levels of self - perceived competency in public health dentistry among male and female dental graduatesto grade the various components of self - perceived public health dentistry competency as reported by newly qualified dentists . to compare the levels of self - perceived competency in public health dentistry among male and female dental graduates to grade the various components of self - perceived public health dentistry competency as reported by newly qualified dentists .
this is a cross - sectional survey - based study which was undertaken in a dental institution in india .
all dental interns ( 133 ) from the klevk institute of dental sciences , belgaum , india participated in the study .
the survey comprised questions in english that is the teaching language of dental colleges in india .
it included 21 close - ended randomly ordered items representing the functions and tasks that are crucial to accomplishing competency in public health dentistry .
the authors ( rbg , pb ) revisited the questions to adopt the study objectives .
five dental interns working at the klevk institute of dental sciences were randomly selected to participate in the pilot study .
all the newly graduates ( 133 ) were requested to assemble in a hall on a predetermined day , and questionnaire with an informed consent and brief outline of the research protocol were distributed .
a full detail of the study was introduced , and all relevant questions were addressed .
all graduates agreed to participate in the study and sufficient time to write their responses was given .
graduates were asked to rate how proficient they perceive themselves on each dental public health function by the using a 3-point likert scale with 0 indicating not at all competent , 1 indicating competent , and 2 indicating very competent .
the overall score was then subdivided into three equal - length categories : from 0 to 13 indicating not at all competent , from 14 to 28 indicating competent , and from 29 to 42 specifying very competent . by using the likert - type scale methodology , the respondents were stratified into three subgroups based on their competency equivalence .
descriptive frequencies were obtained , and the variables were statistically analyzed by using chi - square test . mann
scores for the tasks concerning to motivate health and oral health through health education , to develop activities to motivate the community development , to motivate health and oral health through training of community agents , to motivate health and oral health through creation of healthy settings , and to design , develop and evaluate community preventive interventions
were significantly lower in males than in females ( p = 0.00 , 0.00 , 0.006 , 0.00 , 0.002 , respectively ) while the male students reported greater competency for the function to adjust the dental practice to situations of restriction that limits it
the perception 's scores of participants on the assessed public health functions the sum and mean scores of the 21 items have been calculated to give a total rating , which was 22.61 10.94 indicating that the fresh alumni sensed themselves to be capable of handling the community needs of oral health .
based on the findings mentioned above , dental tasks were ranked in ascending order from the lowest to highest scores .
the four lowest scores were for the tasks to augment the socio economic cultural diagnosis of a community , to design , develop and evaluate community restorative interventions , to manage health care systems to groups , and to adjust the dental practice to situations of restriction that limits it , whereas the four top marks were achieved for the services regarding to motivate health and oral health through health education to augment the oral health diagnosis of a community , to motivate health and oral health through creation of healthy settings , and to motivate health and oral health through training of community agents .
the model of community - based dental education is a learning process derived from simulating real - time experience by giving the students the prospect of training in the community setting . by doing this
, students will learn through community exposure , a wider vision regarding the various social , economic , and cultural elements of the dental and oral health workload that influence the provision of this service on a community scale . integrating the students into community practices empowered them with additional clinical and professional skills to a better understanding of their patients within varied social contexts and settings than they usually get in a traditional dental school clinical encounter . in india , the subject of public health dentistry is taught in the third or final year of undergraduate curriculum with the allotment of 40 - 60 hours of theoretical and 150 hours of practical coaching .
this research aimed to assess the competency grade of the klevk institute of dental sciences graduates ( a premiere dental institute in the state with a well - established department of public health dentistry ) perceive themselves to be for solving oral health needs in the community .
this paper , to the best of our knowledge , is the first study in india for measuring the self - perception of dental public health competency in a cohort of new dental graduates .
dental education is a continuous cycle and starts at dental schools ; students should progress from the beginner stage through the novice stage to the competent stage by the time they graduate .
it is important , therefore , to comprehend the assessed competencies as an integral process rather than individual items .
for example , a student at the dental college could have the competency of performing a restorative procedure technically .
he or she lacks the skills to apply this method in a clinical setting and has limited professional responsibilities associated with this practice .
the advanced beginner level is achieved based on considerable experience and being mentored by a supervisor .
the competent dentist clinically starts to set goals or plans based on hierarchical procedure for making decisions .
proficient dentists comprehend a condition as a whole because they recognize its meaning with regards to long - term objectives . finally , an expert acts from a profound understanding of the entire situation utilizing the large background of experience and highly skilled analytic ability for occasions with no previous experience .
final examinations , clinical case presentations , and supervisor evaluations , in addition to satisfaction survey of patients , students , and alumni are examples of the applied methods to assess the efficiency of a dental curriculum . in this study ,
a questionnaire was used to assess the level of competency which is a reasonable standard to measure the efficacy of dental curriculum .
the self - administered questionnaire is a widely used methodology to assess the self - perceived dental competencies ; however , the risk of bias can not be excluded in this type of studies .
several reports highlighted that students feedback might be affected by the passionate obligation and appreciation to their college for receiving their professional qualification .
our findings indicate that fresh dental graduates assumed themselves competent in resolving the community level oral health needs .
however , they ranked themselves as more experienced in carrying out specific tasks of public health dentistry .
for example , promoting general and oral health through health education scored the highest in self - perception .
this finding is consistent with the results from the study conducted among dental graduates at the universidad peruana cayetano heredia , faculty of stomatology .
it could be due to the design of undergraduate training program that includes oral health education aids ( poster , model ) , tobacco counselling , and school health education programs .
tasks such as to augment the oral health diagnosis of a community , to motivate health and oral health through creation of healthy settings , to motivate health and oral health through training of community agents , to apply basic maintenance to dental equipment and instruments , also were scored highly ; this could be due to the fact that the learning experiences of public health dentistry weighted higher on these activities with a thorough coaching in recording the major indices of oral diseases .
the functions with the lowest scores were to augment the socio - economic - cultural diagnosis of a community , to design , develop and evaluate community restorative interventions , to manage health care systems to groups , to adjust the dental practice to situations of restriction that limits it , and to participate in the epidemiological surveillance system .
special consideration should be given to these lower score functions when planning of curricular changes in dental education is determined .
the approaches of reflective teaching have been proven to be valuable tools to improve the impact of the community learning experiences .
there are several approaches and tools that have shown capability in enhancing the dental education on the basis of community - based learning experiences such as photographic documentation , written narratives , critical incident reports , and mentored post - experiential small group discussions , in addition to fieldwork .
the male brain is characterized by systemizing tendencies ( to use baron - cohen 's term ) and mechanistic thinking ( to use crespi and badcock 's term ) .
systemizing is the motivation to analyze , explore , and construct a system .
in contrast , the female brain is characterized by empathizing tendencies ( to use baron - cohen 's term ) or mentalistic thinking ( to use crespi and badcock 's term ) .
empathizing is the ambition to identify another person 's emotions and thoughts and to respond to them with an appropriate emotion .
this study aimed to understand another person , to predict his or her behavior , and to connect or reverberate with him / her emotionally . in our study , males reported greater competency for the function to adjust the dental practice to situations of restriction that limits it . while the females reported greater competency for the tasks concerning to develop activities to motivate the community development , to motivate health and oral health through health education , and to motivate health and oral health through the creation of healthy settings .
competency - based surveys yield useful information for curriculum review , however , neither they nor any single method of reviewing the curriculum should be used alone .
advances in educational and dental research and the changing dental needs of the population should be factored into the curriculum alongside information from traditional sources such as internal surveys and accreditation reviews .
blunt tools such as competency - based evaluations should be clarified and amplified by focus group interviews to tease out the precise reason for perceived lack of competence in any particular area .
more interestingly , implementing the e - learning assessment has proved to provide a fair evaluation of specific learning domains such as dental public health .
competency - based surveys yield useful information for curriculum review , however , neither they nor any single method of reviewing the curriculum should be used alone
. advances in educational and dental research and the changing dental needs of the population should be factored into the curriculum alongside information from traditional sources such as internal surveys and accreditation reviews .
blunt tools such as competency - based evaluations should be clarified and amplified by focus group interviews to tease out the precise reason for perceived lack of competence in any particular area .
more interestingly , implementing the e - learning assessment has proved to provide a fair evaluation of specific learning domains such as dental public health .
there is a need for additional countrywide data regarding public health dentistry education to enable propagation , exchange , and evaluation of knowledge and skills .
thus , this study is an initial attempt that should be taken further on a larger scale to determine the overall dental public health curriculum competencies .
| aims and objectives : this study aimed to assess how competent the recent dental graduates perceive themselves to be in dental public health.materials and methods : a 21-item structured , close - ended questionnaire study was carried out at the klevk institute of dental sciences , belgaum , india .
students assessed their competencies using a three - point ordinal scale .
one hundred and thirty - three students were asked to rate their proficiency on a 21-item matrix of the dental public health program .
the responses were grouped using the likert - type scale .
frequencies descriptive data were generated , and statistical analysis of examined variables was carried out using the chi - square test . mann
whitney test was conducted to identify the correlation between variables.results:the overall mean score was 22.61 10.94 , highlighting confidence of the graduates in managing the oral health problems at the community level .
females showed higher competencies in functions related to develop activities to motivate the community development , to motivate health and oral health through health education , and to motivate health and oral health through the creation of healthy settings . while males reported greater competency for the function to adjust the dental practice to situations of restrictions that limits it.conclusion:recent dental graduates at the institute perceived themselves competent in managing oral and dental health problems at the public level .
additional countrywide evidence regarding teaching and learning of public health dentistry is essential to compare the current experiences of dental graduates and ultimately enhance patient care . |
the theory that events in the perinatal period have latent effects throughout the life course has become increasingly accepted .
the literature on the fetal - origins hypothesis strongly suggests that while maternal malnutrition and poor maternal health might not cause major malformations in childhood , such exposures can nevertheless have enduring , or latent , effects such as restricted growth , hypertension , cardiovascular events , and altered renal function in adulthood .
[ 1 , 2 ] these potential maternal environments can be physiological ( e.g. , maternal metabolic regulation ) , psychobehavioral ( e.g. , stress , smoking ) , and/or ecological ( e.g. , poverty , unstable food supply ) .
the literature is emerging on how these environments affect the long - term growth and health of children as they develop into adulthood .
[ 35 ] a recently published review of 135 studies to evaluate factors in early childhood ( 5 years of age ) that are the most significant predictors of the development of obesity in adulthood reported that possible early markers of obesity included maternal smoking and maternal weight gain during pregnancy .
probable early markers of obesity included maternal body mass index , childhood growth patterns ( early rapid growth and early adiposity rebound ) , childhood obesity , and father 's employment ( a proxy measure for socioeconomic status [ ses ] in many studies ) .
other recent studies have examined the relationship between prenatal exposures such as smoking during pregnancy and early feeding practices ( e.g. , breastfeeding , early introduction of solid foods ) and adverse cardiovascular health outcomes in preschool age children [ 7 , 8 ] . results of these studies showed that maternal smoking during pregnancy was associated with a higher body mass index ( bmi ) at four years of age in children with a normal birth weight and in those who were small for gestational age at birth and that shorter breastfeeding duration and exclusivity ( no formula or solid food ) during the first 6 months tended to be associated with increased growth rates for length , weight and bmi between the age of 3 and 6 months but not with the risks of overweight and obesity until the age of 3 years .
early childhood is an important stage of growth to examine given that one in four us children under age 5 is either overweight ( 85th to < 95th age- and sex - adjusted percentiles for bmi ) or obese ( 95th age- and sex - adjusted percentiles for bmi ) [ 9 , 10 ] .
overweight preschool - age children are five times more likely to be overweight during adolescence and more than four times as likely to become obese as adults than are their normal - weight counterparts .
recent studies have shown that obesity in this age range is associated with cardiovascular disease risk factors and varies by ethnic group .
the concern is that childhood overweight will contribute to the earlier onset of overall morbidity and mortality in adulthood , making early intervention crucially important [ 4 , 5 ] .
preschool children are at an ideal age to examine these relationships because there are fewer exposures to environmental confounders and interactions compared to older children and adults when it might be much more challenging to distinguish the contribution of the environment versus physiology .
the relationship between overweight / obesity , cardiovascular disease ( cvd ) risk factors and birthweight , mother 's smoking status during pregnancy , breastfeeding , and early introduction of solids and how these relationships vary by ethnic group specifically is largely unknown .
therefore , we assessed these relationships in a population - based multiethnic sample of 3-to-6-year - olds to determine the influence of breastfeeding , early introduction of solid foods , smoking during pregnancy , and low birth weight on the prevalence of cvd risk factors .
the periodic national health and nutrition examination survey ( nhanes ) uses a stratified , multistage probability design to capture a representative sample of the civilian , noninstitutionalized us population
. this design allows survey results from two or more periods to be combined to increase the sample size and analytic options . each 2-year period , and any combination of 2-year periods ,
is a nationally representative sample . to produce estimates with greater statistical reliability for demographic subgroups and rare events , combining two or more 2-year periods of the survey results
therefore , for this study , nhanes data files for 1999 - 2000 , 2001 - 2002 , 2003 - 2004 , 2005 - 2006 , and 2007 - 2008 were combined to form a single analytic file . from the above - cited nhanes
19992008 data file all non - hispanic white ( nhw ) , hispanic ( mexican american , other hispanic groups combined ) , and non - hispanic black ( nhb ) boys and girls aged 3 to 6 years and their mothers were included .
the following measurements were available for analysis in this age group : age , sex , ethnicity , height and weight ( for bmi ) , wc , c - reactive protein ( crp ) , total cholesterol , high - density lipoprotein ( hdl ) , low - density lipoprotein ( ldl ) cholesterol , and triglycerides ( available in the morning - only randomized subsample ) .
using data on response rates found on the cdc website , we estimated the total number of 3-to-6-year - old children who were screened in the surveys from 19992008 to be 4,627 .
of the children screened , 4,091 ( 88% ) participated in the interview and 3,876 ( 84% ) participated in the examination .
we eliminated 225 children who were in the other ethnic group category ( not hispanic , nhw or nhb ) and another 7 children who were diabetic or on metabolic altering drugs ; therefore , our analytic sample included 3,644 children ( 79% of children screened ) . with a sample size of more than 1000 in each ethnic group ( table 2 ) , it is possible to detect a small effect size of 0.20 at the two - tailed 0.05 level with 80% power .
persons selected to participate in the nhanes survey were invited to be interviewed in their homes .
household interview data were collected with computer - assisted personal interviewing procedures and included demographic , socioeconomic , dietary , and health - related information . because the children were so young ( less than 7 years old ) , the mothers answered all questions on their behalf .
mothers were asked questions about their pregnancy with the index child included in this analysis .
specifically included were the responses regarding self - reported smoking status during pregnancy , infant birthweight , whether the infant was breastfed , and if solid foods were introduced in the infant 's diet before six months of age . after the interview ,
laboratory and anthropometric measurement methods used at the medical examination centers are described in the nhanes laboratory / medical technologists procedures manual .
briefly , anthropometric measures taken during the standardized examination consisted of barefoot standing height ( with a stadiometer ) , weight with minimal clothing ( on a digital , electronic scale ) , and waist circumference ( in the horizontal plane at a point marked just above the right ileum on the midaxillary line , at minimal respiration after normal expiration ) [ 16 , 17 ] .
triglycerides and low - density lipoprotein ( ldl ) cholesterol were measured via blood on a nonfasting subsample ( those who were examined in the morning session only ) of all children ages 3 to 11 ( n = 626 ) .
all serum blood samples were collected , processed , stored at 20c , and shipped to the lipid laboratory , johns hopkins university , baltimore , md ( lipids ) for the19992006 surveys and to the university of minnesota , minneapolis , mn , for the 2007 - 2008 survey for analysis .
high - density lipoprotein ( hdl ) cholesterol was measured in supernatants after precipitation of apo b - containing lipoproteins with heparin - manganese chloride and removal of excess manganese by precipitation with sodium bicarbonate .
triglycerides were analyzed enzymatically with the use of commercial reagents and was measured in edta plasma after hydrolysis by lipoprotein lipase to glycerol and fatty acids .
glycerol is enzymatically phosphorylated and then oxidized to release hydrogen peroxide , which is peroxidized to form a quinine - imine chromophore that can then be read at 490 to 550 nm in a spectrophotometer .
low - density lipoprotein cholesterol ( ldl ) was derived using the friedewald calculation ( ldl = total cholesterol - hdl cholesterol - triglyceride/5 ) .
crp was quantified by latex - enhanced nephelometry ( crp present in the test sample forms an antigen antibody complex with the latex particles ) .
serum blood specimens were processed , stored and shipped to university of washington , seattle , wa .
particle - enhanced assays were based on the reaction between a soluble analyte and the corresponding antigen or antibody bound to polystyrene particles .
a dilute solution of test sample was mixed with latex particles coated with mouse monoclonal anti - crp antibodies .
non - hdl cholesterol is defined as total cholesterol minus hdl cholesterol . the highest quintile for crp , total cholesterol , ldl cholesterol , non - hdl cholesterol and triglycerides and the lowest quintile for hdl cholesterol , for the entire study population were used as cut - points for analysis ( table 1 ) .
these cut - points are consistent with the percentages used for abnormal values in studies of older children [ 20 , 21 ] .
logistic regression analysis was used to explore the relationships between each of the selected perinatal and infant conditions and anthropometric measurements and cvd risk factors for each ethnic group .
child 's age and sex , the family 's poverty / income ratio , the year of the survey ( to account for possible trend over the 10 years of data ) , and mother 's age at the child 's birth were included in each model to control for potential confounding effects .
analyses were performed with sas survey procedures ( sas version 9.2 , sas institute , cary , nc ) to accommodate the complex sample survey design of the nhanes data .
alpha was set at 0.05 and all tests were two tailed , without correction for multiple comparisons .
we analyzed data from 3,644 ( weighted sample size , 14,535,068 ) children and their mothers ( tables 2 and 3 ) .
overall , 13.8% of children had a bmi 95th percentile and 26.5% had a bmi 85th percentile for age and sex ( table 1 ) .
almost 10% of the infants were low birth weight ( < 2500 grams ) and 17% of the mothers reported smoking while being pregnant ( table 3 ) .
table 4 shows that breastfeeding was significantly protective against obesity ( bmi 95th percentile ile for age and sex ) ( or 0.43 , 95% ci , 0.270.69 ) , overweight ( or 0.61 , 95% ci , 0.420.87 ) , and being in the highest quintile for waist circumference ( or 0.58 , 95% ci , 0.370.92 ) among the nhw group and against highest quintile for non - hdl cholesterol among nhb ( or 0.56 , 95% ci , 0.320.98 ) .
conversely , introducing solid foods before 6 months was not shown to be a risk factor for any cvd risk factors among all ethnic groups .
smoking during pregnancy was a significant risk factor for obesity ( or 2.22 , 95% ci , 1.132.83 ) , overweight ( or 1.79 , 95% ci 1.132.83 ) , and highest quintile of crp ( or 1.63 , 95% ci , 1.052.51 ) among nhw ( table 5 ) .
table 6 shows that in general low birth weight was not a risk factor for becoming overweight or obese or having elevated cvd risk factors in this age group was associated with a diminished risk among nhw for being overweight ( or 0.33 , 95% ci 0.140.76 ) and having the highest quintile of waist circumference ( or 0.34 , 95% ci 0.160.74 ) .
the results reported here show that cvd risk in young children is associated with perinatal and infancy factors among nhw .
specifically , our analysis shows that breastfeeding is protective against obesity and smoking during pregnancy is a risk factor for obesity in nhw .
low birth weight was not a risk factor for cvd risk factors , particularly among nhw women . with the exception of breastfeeding being protective against the highest quintile of non - hdl cholesterol in nhb , early introduction of solid foods , smoking during pregnancy , and low birth weight
previous nhanes analyses have shown mixed results when analyzing whether or not breastfeeding is protective against children becoming overweight and that there is a dose - dependent effect based on duration .
one analysis of infant feeding and child overweight status among 3-to-5-year olds from the nhanes iii showed that after adjusting for potential confounders , there was a reduced risk of being overweight for ever - breastfed children compared with those never breastfed .
furthermore , there was no demonstrable threshold effect or clear dose - dependent effect of the duration of full breastfeeding on being at risk of overweight or overweight ( now termed overweight and obese ) .
other large population - based studies have also examined whether increasing duration of breastfeeding is associated with a lower risk of overweight in a low - income population of 4-year olds in the united states .
analysis from the pediatric nutrition surveillance system of children up to 60 months of age found that the duration of breastfeeding showed a dose - response , protective relationship with the risk of overweight only among nhw ; no significant association was found among nhb or hispanics , very similar to our results reported here .
others have examined a broad range of factors that may simultaneously contribute to childhood overweight in a population - based cohort of children followed from birth to 4.5 years , to determine which factors exert the most influence in early life .
the quebec longitudinal study of child development 19982002 ( qlscd ) followed a representative sample ( n = 2103 ) of children born in 1998 in the canadian province of quebec . measured height and weight were available for 1550 children aged 4.5 years .
results showed that being in the highest quintiles of weight gain between birth and 5 months , as well as maternal smoking during pregnancy , almost doubles the odds of being overweight at 4.5 years .
the viva la familia study was designed to identify genetic and environmental factors affecting obesity and its comorbidities in 1030 hispanic children from 319 families .
salient independent risk factors for childhood obesity in this cohort of hispanic children were age , birth weight , maternal obesity , paternal obesity , number of children in the family , and the percentage of awake time spent in sedentary activity .
they also reported that breastfeeding might have a small protective effect against childhood obesity , although the authors concluded that residual confounding might exist .
the authors reported no significant effect of early introduction of solid foods on childhood obesity , consistent with our findings here .
conversely , a prospective nationally representative cohort study conducted in england , wales , scotland , and northern ireland included 13,188 singleton children aged 3 years in the millennium cohort study , born between 2000 and 2002 , who had complete height / weight data .
the main outcome measure was childhood overweight ( including obesity ) defined by the international obesity task force cut - offs for body mass index . in the fully adjusted model , primarily individual- and
family - level factors were associated with early childhood overweight : birthweight z - score , black ethnicity ( compared with white ) , introduction to solid foods < 4 months , and smoking during pregnancy . however , in agreement with both the findings here and in the viva la familia study , breastfeeding 4 months ( compared with none ) was associated with a decreased risk of early childhood overweight .
other population - based studies have shown an association between maternal smoking during pregnancy and childhood obesity .
specifically , a total of 11,653 preschool children participating in the uk millennium cohort study had their weight gain z - scores calculated from 3 to 5 years . in a mutually adjusted model , children were more likely to gain weight rapidly if their mothers smoked during pregnancy . due to the cross - sectional nature of the current dataset , we were unable to explore longitudinal growth but the concept of catch - up growth has gained recent and increased attention in the literature [ 2830 ] . because our findings are among very young children , they may have implications throughout childhood .
our group has reported previously that risk factors for cardiometabolic disease can be detected as early as the preschool years ( 12 ) and 8 years old .
other studies have noted that several cvd risk factors persist strongly and consistently through childhood into adulthood [ 32 , 33 ] .
the cardiovascular risk in young finns study was one of the first groups to explore childhood predictors of the metabolic syndrome ( ms ) , a constellation of abnormal waist circumference , insulin resistance , dyslipidemia , and hypertension . in this study , fasting insulin at baseline was related to development of the syndrome after a 6-year follow - up of 1,865 children and adolescents 6-to-18-years - old .
reported results showed that baseline insulin concentration was higher in children who subsequently developed the ms , lending support to the theory that insulin resistance precedes the development of the condition in childhood .
blood pressure , insulin and glucose measures , which are important components of metabolic syndrome and risk factors for adult - onset cvd and diabetes , were not collected in this age group and thus were not available for analysis . because triglycerides and ldl were measured on a subsample of the surveyed children , analyses for these variables may not have sufficient statistical power to detect significant differences .
dietary and physical activity level data were not included because the children in this analysis were so young and their eating and exercise patterns tend to be inconsistent as a result .
smoking status during pregnancy and infant feeding behaviors were self - reported and therefore subject to systematic biases .
this study indicates that behavioral and social factors exert critical influences on the onset of childhood overweight in preschool years among nhw families in particular . regardless of ethnic background
, all women should be advised not to smoke , especially while being pregnant , and should be encouraged to breastfeed , unless contraindicated , as a means of providing optimal nutrition .
this may in turn prove to be protective against chronic obesity and later life onset of cvd .
this paper is funded by national institutes of health grant k01 da 026993 ( sem ) . | we examined the relationships between selected perinatal and early infancy factors ( maternal smoking during pregnancy , infant low birthweight , breastfeeding , and early introduction of solid foods [ < 6 months of age ] and increased bmi [ 85th , 95th percentiles for age , sex ] ) , waist circumference ( wc ) , c - reactive protein ( crp ) , triglycerides , total cholesterol , low - density lipoprotein ( ldl ) cholesterol , non - high - density lipoprotein ( hdl ) cholesterol , and decreased hdl cholesterol during early childhood .
the population - based sample included 3,644 3-to-6-year - old non - hispanic white ( nhw ) , hispanic , and non - hispanic black ( nhb ) children who participated in the 19992008 national health and nutrition examination surveys .
analysis showed that breastfeeding was significantly protective against early childhood obesity ( or 0.43 , 95% ci , 0.270.69 ) and the highest quintile for wc ( or 0.58 , 95% ci , 0.370.32 ) among nhw , and against the highest quintile of non - hdl cholesterol among nhb ( or 0.56 , 95% ci , 0.320.98 ) .
additionally , nhw children were significantly more likely to be obese ( or 2.22 , 95% ci 1.303.78 ) and have higher crp levels ( or 1.63 , 95% ci , 1.052.51 ) if their mothers smoked during pregnancy .
these results support the observation that breastfeeding may be protective against early childhood obesity while maternal smoking during pregnancy is a risk factor for obesity and increased crp levels among nhw young children . |
atherosclerosis , a systemic disease characterized by deposition of fatty materials , inflammatory cells , and scar tissue within the arterial walls , is the major cause of cardiovascular and cerebrovascular events . in developed countries ,
atherosclerosis - related cardiovascular and cerebrovascular events are estimated to be the cause of death in 50% of cases .
although the cerebral and carotid atherosclerosis develops later than coronary atherosclerosis , stroke and myocardial infarction share common cardiovascular risk factors , such as hypertension , diabetes mellitus , smoking , and hyperlipidemia , and generally begin to occur at similar age with similar age - specific event rates .
intracranial atherosclerosis occurs in > 80% of older white persons with significant associations with conventional cardiovascular risks factors . as coronary artery calcification
is highly correlated with the atherosclerotic burden and risk for future cardiovascular events , intracranial artery calcification is reasonably considered a potential risk factor for cerebral ischemic stroke .
a number of studies utilizing different methods to measure the calcium burden of the carotid arteries have shown discordant results .
some authors believed that calcifications stabilize plaques whereas others stated an increased risk of thromboembolic disease associated with the calcifications . in a recent large population - based cohort study using noncontrast computed tomography ( ct ) of the calcified plaques , bos et al established intracranial carotid artery calcification as an independent risk factor for stroke .
although the middle cerebral artery ( mca ) usually shows less calcium burden on ct than the intracranial carotid artery does , calcification of the mca may play a crucial role due to its proximity to the ischemic event .
previous studies used a binary or a morphology - based qualitative grading method to measure intracranial calcifications . in coronary artery studies ,
a more sophisticated and quantitative measure of calcification using the agatston score has been employed by computing the products of ct - density - based weighted scores and areas of calcified lesions .
this scoring method can be easily applied semiautomatically to mca calcifications whereas it is difficult to be applied to the intracranial internal carotid artery due to its proximity to the bony structures of the skull base . in this study
, we hypothesized that subjects with a higher burden of mca calcification are more likely to have an ischemic stroke than those with lower or no burden .
therefore , the purpose of our study was to quantitatively investigate whether the mca calcification is associated with ischemic cerebral stroke in the corresponding territory using the agatston calcium scoring method .
this study was approved by the institutional review board of tri - service general hospital , national defense medical center , taipei , taiwan , and the requirement for written informed consent from the subjects ( or from the next of kin / caregiver ) for use of the clinical records of the subjects was waived . all subject records / information was anonymized and deidentified before analysis .
our data are available upon request because of an ethical restriction of the institutional review board .
a total of 2260 consecutive subjects underwent noncontrast brain studies in our 64-slice multidetector - row ct examination suite ( brilliance 64 , philips medical systems , best , the netherlands ) for a variety of clinical indications , which were mainly head trauma ( 562 subjects , 24.9% ) , stroke ( 485 , 21.5% ) , headaches ( 462 , 20.4% ) , dementia ( 388 , 17.2% ) , brain tumors ( 87 , 3.8% ) , and seizures ( 36 , 1.6% ) .
we excluded a total of 388 subjects ( 17.2% ) mainly due to age < 40 years old ( 314 , 80.9% ) , followed by clinical history or imaging findings of intracranial hemorrhage ( 75 , 19.3% ) , brain tumors ( 19 , 4.9% ) , and brain infections ( 3 , 0.8% ) .
a total of 1872 subjects ( 865 women and 1007 men ; mean age , 66 years ; range , 4199 ) were eligible for analysis .
subjects having matched clinical and imaging findings of cerebral infarct in the mca territory were assigned to the mca stroke group whereas the rest were assigned to the control group .
magnetic resonance ( mr ) imaging diagnosis of acute cerebral infarction was made by visualization of high signal intensities on diffusion - weighted images and corresponding low signal intensities on apparent diffusion coefficient maps .
two board - certificated neuroradiologists ( hwk and cyc with 25 and 10 years of clinical experience in neuroimaging interpretation respectively ) , blinded to the clinical information of the subjects , reviewed all the ct and mr images from our picture archiving and communication system to record imaging evidences of cerebral infarct .
major known risk factors of ischemic stroke were documented from medical record review and analysis of electronic health records in our hospital information system .
subjects were diagnosed as hypertensive if they presented systolic blood pressure > 140 mm hg or diastolic blood pressure > 90 mm hg or if they were on any antihypertensive medication .
subjects were marked smokers if smoking > 1 cigarette / day over the preceding year before the ischemic stroke .
the hyperlipidemia was defined based on the history of lipid - lowering therapy or serum total cholesterol level of > 200 mg / dl .
all ct examinations were performed with a standardized noncontrast protocol ( 120 kvp ; 280 ma ; collimation , 40 0.625 mm ; table feed , 14.4 mm / rotation ; pitch , 0.58 ) .
image reconstructions were made with a field of view of 100 mm ; matrix size , 512 512 ; slice thickness , 3.0 mm ; increment , 0.5 mm . for quantification of the mca calcium burden ,
all reconstructions were transferred to an independent pc - based workstation ( syngo cascoring wizard , siemens medical solutions , erlangen , germany ) . according to the agatston method , ct density
130 hounsfield units in 2 continuous pixels were automatically marked in color by the workstation .
the 2 neuroradiologists defined the regions of interests ( rois ) by scrutinizing the bilateral mcas on both axial and reconstructed coronal ct images ( figure 1 ) .
the agatston score of each roi in the bilateral mcas was generated by the workstation and the scores from each mca were summed .
the bilateral mca agatston scores were then added up to a total mca agatston score . for subjects with multiple brain ct examinations ,
( a ) axial and ( b ) coronal noncontrast ct images demonstrate 2 calcifications ( rca 1 and 2 ; agatston score , 52.3 ) with density > 130 hounsfield units in 2 continuous pixels , automatically highlighted in pink color by the workstation .
the rca , an acronym of the right coronary artery , is referred to the right mca in this study .
the hemisphere of cerebral infarct was attributed to the left , right , or both mca territories .
the between - group differences in risk factors for ischemic stroke were evaluated for statistical significance with the mann
whitney u test for continuous variables and with the fisher exact test for categorical variables because the data were not normally distributed .
significant risk factors in the univariate tests were included as predictors in modified logistic regression models , which had more accurate regression parameter estimates by reference to valid information identities . in these models ,
ischemic strokes on both or either side of the mca territories were considered the response variable and odds ratios and 95% confidence intervals ( ci ) of the risk factors were estimated .
the adjusted effect of the individual mca calcification on ipsilateral cerebral infarct was evaluated in the modified logistic regression models .
the intraclass correlation coefficient was used to evaluate inter - rater agreement of the selected rois .
the statistical significance was evaluated using the 2-tailed test in the univariate analyses and type - iii likelihood ratio statistic for each predictor in the model along with the wald ci for the parameter estimates in the modified logistic regression model , both with the nominal type - i error at the 5% level .
all the statistical analyses were performed with an ibm spss statistics for mac ( version 20 ; ibm corp . , armonk
this study was approved by the institutional review board of tri - service general hospital , national defense medical center , taipei , taiwan , and the requirement for written informed consent from the subjects ( or from the next of kin / caregiver ) for use of the clinical records of the subjects was waived . all subject records / information was anonymized and deidentified before analysis .
our data are available upon request because of an ethical restriction of the institutional review board .
a total of 2260 consecutive subjects underwent noncontrast brain studies in our 64-slice multidetector - row ct examination suite ( brilliance 64 , philips medical systems , best , the netherlands ) for a variety of clinical indications , which were mainly head trauma ( 562 subjects , 24.9% ) , stroke ( 485 , 21.5% ) , headaches ( 462 , 20.4% ) , dementia ( 388 , 17.2% ) , brain tumors ( 87 , 3.8% ) , and seizures ( 36 , 1.6% ) .
we excluded a total of 388 subjects ( 17.2% ) mainly due to age < 40 years old ( 314 , 80.9% ) , followed by clinical history or imaging findings of intracranial hemorrhage ( 75 , 19.3% ) , brain tumors ( 19 , 4.9% ) , and brain infections ( 3 , 0.8% ) .
a total of 1872 subjects ( 865 women and 1007 men ; mean age , 66 years ; range , 4199 ) were eligible for analysis .
subjects having matched clinical and imaging findings of cerebral infarct in the mca territory were assigned to the mca stroke group whereas the rest were assigned to the control group .
magnetic resonance ( mr ) imaging diagnosis of acute cerebral infarction was made by visualization of high signal intensities on diffusion - weighted images and corresponding low signal intensities on apparent diffusion coefficient maps .
two board - certificated neuroradiologists ( hwk and cyc with 25 and 10 years of clinical experience in neuroimaging interpretation respectively ) , blinded to the clinical information of the subjects , reviewed all the ct and mr images from our picture archiving and communication system to record imaging evidences of cerebral infarct .
major known risk factors of ischemic stroke were documented from medical record review and analysis of electronic health records in our hospital information system .
subjects were diagnosed as hypertensive if they presented systolic blood pressure > 140 mm hg or diastolic blood pressure > 90 mm hg or if they were on any antihypertensive medication .
subjects were marked smokers if smoking > 1 cigarette / day over the preceding year before the ischemic stroke .
the hyperlipidemia was defined based on the history of lipid - lowering therapy or serum total cholesterol level of > 200 mg / dl .
all ct examinations were performed with a standardized noncontrast protocol ( 120 kvp ; 280 ma ; collimation , 40 0.625 mm ; table feed , 14.4 mm / rotation ; pitch , 0.58 ) .
image reconstructions were made with a field of view of 100 mm ; matrix size , 512 512 ; slice thickness , 3.0 mm ; increment , 0.5 mm .
for quantification of the mca calcium burden , all reconstructions were transferred to an independent pc - based workstation ( syngo cascoring wizard , siemens medical solutions , erlangen , germany ) . according to the agatston method , ct density
130 hounsfield units in 2 continuous pixels were automatically marked in color by the workstation .
the 2 neuroradiologists defined the regions of interests ( rois ) by scrutinizing the bilateral mcas on both axial and reconstructed coronal ct images ( figure 1 ) .
the agatston score of each roi in the bilateral mcas was generated by the workstation and the scores from each mca were summed .
the bilateral mca agatston scores were then added up to a total mca agatston score . for subjects with multiple brain ct examinations ,
( a ) axial and ( b ) coronal noncontrast ct images demonstrate 2 calcifications ( rca 1 and 2 ; agatston score , 52.3 ) with density > 130 hounsfield units in 2 continuous pixels , automatically highlighted in pink color by the workstation .
the rca , an acronym of the right coronary artery , is referred to the right mca in this study .
the hemisphere of cerebral infarct was attributed to the left , right , or both mca territories .
the between - group differences in risk factors for ischemic stroke were evaluated for statistical significance with the mann
whitney u test for continuous variables and with the fisher exact test for categorical variables because the data were not normally distributed .
significant risk factors in the univariate tests were included as predictors in modified logistic regression models , which had more accurate regression parameter estimates by reference to valid information identities . in these models ,
ischemic strokes on both or either side of the mca territories were considered the response variable and odds ratios and 95% confidence intervals ( ci ) of the risk factors were estimated .
the adjusted effect of the individual mca calcification on ipsilateral cerebral infarct was evaluated in the modified logistic regression models .
the intraclass correlation coefficient was used to evaluate inter - rater agreement of the selected rois .
the statistical significance was evaluated using the 2-tailed test in the univariate analyses and type - iii likelihood ratio statistic for each predictor in the model along with the wald ci for the parameter estimates in the modified logistic regression model , both with the nominal type - i error at the 5% level .
all the statistical analyses were performed with an ibm spss statistics for mac ( version 20 ; ibm corp . ,
of the 1872 subjects in our study , the most prevalent major known risk factor in our subjects was hypertension ( 51.1% ) , followed by diabetes mellitus ( 26.1% ) , smoking ( 22.1% ) , hyperlipidemia ( 19.6% ) , and obesity ( 3.3% ) .
a total of 354 ( 18.9% ) subjects ( mean age , 72 years ; range , 4199 years ) were in the mca stroke group and 1518 ( 81.1% ) subjects ( mean age , 64 years , range 4199 years ) were in the control group . in the mca stroke group , 237 ( 66.9% )
subjects underwent mr imaging for confirmation of the cerebral infarct within a median of 1 day ( interquartile range , 03 ) after the brain ct study . among those ,
157 ( 66.2% ) subjects showed acute cerebral infarcts in the mca territory whereas 80 ( 33.8% ) showed old infarcts in the territory matching clinical histories and symptoms .
a total of 73 out of 1872 ( 3.9% ) subjects had calcifications on both or either side of the mca in a wide range of total mca agatston scores ( median , 3.8 ; range , 0.1436.1 ) .
the inter - rater reliability index of the total mca agatston scores was high ( intraclass correlation coefficient = 0.998 ) .
the univariate analyses showed significant associations of ischemic stroke with age , hypertension , diabetes mellitus , smoking , total mca agatston score , and presence of calcification on both or either side of the mca , disregarding laterality of the mca calcification and hemispheric infarct . among the documented risk factors for ischemic stroke ,
mca calcifications were significantly associated with age and hypertension and marginally associated with hyperlipidemia and obesity ( table 2 ) .
characteristics of the subjects in the study associations of mca calcification and risk factors for ischemic stroke the modified logistic regression models showed significant associations between ischemic stroke and the significant risk factors identified in the univariate analyses . considering interactions between the confounders in logistic regression models , we found no interaction between the age and the gender ( p = 0.53 ) whereas hypertension , diabetes mellitus , and smoking significantly attenuated the association between age and ischemic infarct ( odds ratios , 1.06 vs 1.04 , p = 0.02 ; 1.06 vs 1.02 , p < 0.001 ; 1.06 vs 1.03 , p = 0.02 respectively ) . after adjustment for age , hypertension , diabetes mellitus , and smoking , subjects with the presence of mca calcification on both or either side of the mca were 8.46 times ( 95% ci , 4.9314.53 ; p <
0.001 ) more likely to have a cerebral infarct than subjects without mca calcification ( table 3 , model 1 ) .
a higher degree of mca calcification reflected by the agatston score was not significantly associated with higher risk of mca ischemic stroke after adjustment for the confounding factors and the presence of mca calcification ( 95% ci , 0.981.07 ; p = 0.29 ; table 3 , model 2 ) .
mca calcification and risk factors for ischemic stroke in modified logistic regression analyses by subject among the 73 subjects with mca calcifications , 52 ( 71.2% ) showed calcifications on the right side , 37 ( 50.7% ) on the left side , and 16 ( 21.9% ) on both sides .
the adjusted odds ratios for the cerebral infarct on the ipsilateral side of the mca calcification were 8.67 ( 95% ci , 4.7515.82 ; p < 0.001 ) on the right and 10.50 ( 95% ci , 5.1421.42 ; p < 0.001 ) on the left , even after controlling for the familywise type - i error rate at 0.05 via bonferroni correction ( table 4 ) .
first , the mca calcification was significantly associated with cerebral infarct in the corresponding territories after adjustment for the major known risk factors , including age , hypertension , diabetes mellitus , and smoking .
second , a higher degree of mca calcification reflected by the agatston score was not significantly associated with higher risk of mca ischemic stroke after adjustment for the confounding factors and the presence of mca calcification .
atherosclerosis is a systemic disease , commonly present in the aorta , coronary artery , and carotid arteries .
many risk factors have been shown to correlate with coronary artery calcification , including old age , elevated serum cholesterol , elevated triglycerides , diminished high - density lipoprotein cholesterol , hypertension , diabetes mellitus , smoking , and obesity . in line with the findings in the literature , our results showed significant correlations between mca calcification and the risk factors for ischemic stroke , including old age and hypertension .
the predictive value of arterial calcification for stroke has been established in studies focusing on the coronary arteries , aortic arch , and extracranial and intracranial carotid arteries .
our results further extend these evidence to the mca and support a systemic effect of cardiovascular risk factors , by which calcified plaques , advanced stages of atherosclerosis , play a significant role in stroke events .
this study , to the best of our knowledge , is the first to apply the quantitative agatston score to investigate the correlation between the mca calcification and the corresponding ischemic stroke .
the scoring method is advantageous in reflecting the calcium burden on the artery of interest as a whole rather than a focal morphological abnormality . in the study of nandalur
et al , the degree of calcification in the extracranial carotid artery is significantly associated with luminal stenosis and ischemic symptoms .
large randomized trials have also shown the association of carotid stenosis and stroke as well as the benefit of carotid endarterectomy .
in contrast to the effect of arterial calcifications in the coronary and carotid arteries , the implication of atherosclerosis of the mca is less investigated .
this issue is particularly important in populations of chinese and african ancestries in whom stenosis of the large intracranial artery is a common cause of ischemic stroke . in a study of intracranial arterial calcifications ,
kassab et al found that the presence of calcification on head ct appears to correlate with the presence of intracranial stenosis on catheter angiography .
accordingly , the mca calcification is a reasonable risk factor of ischemic stroke in the corresponding cerebral territories , a hypothesis supported by the results of our study . among the documented risk factors in our study ,
the presence of mca calcification was a less common but strong risk factor associated with ischemic stroke .
the findings may imply a contribution to ischemic stroke from a calcification - related stenosis of the mca , which may lead to regional hemodynamic disturbance .
however , the degree of mca calcification reflected by the calcium scores represented only 1 important characteristic of the atherosclerotic plaque .
therefore , in patients with the strong risk factor , mca calcification , increased mca calcium burden might not necessarily parallel increased degree of arterial stenosis or the risk of ischemic stroke . in the study of kassab
et al , the calcium grade of the intracranial artery , semi - quantified with a 5-point system , is not unexceptionally consistent with the dichotomous degree of stenosis . in clinical practice
, we do not suggest performing calcium quantification because the significant high risk of ischemic infarct could have already been implied by the presence of mca calcification itself .
the strength of our study was the application of the accurate and objective agatston scoring method to measure the mca calcium burden .
furthermore , we assessed clinical and brain ct findings to categorize subjects , a method to unravel a direct causal relationship between mca calcification and ischemic stroke in the corresponding territories .
however , the number of subjects with mca calcification was relatively small because of its low prevalence rate
. the limitations of our study were basically due to the retrospective design and the fact that the included subjects were from only 1 local medical center .
although all subjects with indications for brain ct were included in our study , there remained a probability of selection bias .
in addition , some significant but less common risk factors for ischemic stroke , such as mitral stenosis , sickle cell disease , and hyperhomocysteinemia , were not evaluated in our study .
the agatston calcium scoring method used in our study was semiautomatic and required manual selection of the mca calcification .
however , the neuroradiologists generally had no difficulty in selecting rois for the segmentation of the calcification on ct images .
another potential limitation was the fact that the cerebral embolic infarct may mimic thrombotic infarct and confound the analysis .
furthermore , an evaluation of the noncalcified plaque and the correlation between mca calcium burden and luminal stenosis requires administration of contrast material , not included in our routine stroke workup , was not available in our study .
in conclusion , our study shows that mca calcification is associated with ischemic stroke after adjustment for age , hypertension , diabetes mellitus , and smoking . | abstractcalcification of the middle cerebral artery ( mca ) is uncommon in the healthy elderly .
whether calcification of the mca is associated with cerebral ischemic stroke remains undetermined .
we intended to investigate the association using agatston calcium scoring of the mca .
this study retrospectively included 354 subjects with ischemic stroke in the mca territory and 1518 control subjects who underwent computed tomography ( ct ) of the brain .
we recorded major known risk factors for ischemic stroke , including age , gender , hypertension , diabetes mellitus , smoking , hyperlipidemia , and obesity , along with the mca calcium burden , measured with the agatston calcium scoring method .
univariate and modified logistic regression analyses were performed to examine the association between the mca calcification and ischemic stroke.the univariate analyses showed significant associations of ischemic stroke with age , hypertension , diabetes mellitus , smoking , total mca agatston score , and the presence of calcification on both or either side of the mca .
subjects with the presence of mca calcification on both or either side of the mca were 8.46 times ( 95% confidence interval , 4.9314.53 ; p <
0.001 ) more likely to have a cerebral infarct than subjects without mca calcification after adjustment for the major known risk factors , including age , hypertension , diabetes mellitus , and smoking .
however , a higher degree of mca calcification reflected by the agatston score was not associated with higher risk of mca ischemic stroke after adjustment for the confounding factors and presence of mca calcification .
these results suggest that mca calcification is associated with ischemic stroke in the mca territory .
further prospective studies are required to verify the clinical implications of the mca calcification . |
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