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Intracellular chemical imaging of the developmental phases of human neuromelanin using synchrotron X-ray microspectroscopy.
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The microchemical environment of neuromelanin (NM) in whole neurons from formalin fixed and paraffin embedded human substantia nigra sections were characterized using synchrotron chemical X-ray microscopy. Concentrations of NM-associated elements increased in the developing brain; the highest levels of most elements were found in the mature brain but the temporal pattern of the accumulation of different elements varied. High spatial resolution investigations, using a unique hard X-ray nanoprobe, revealed iron-rich microdomains colocalized with other elements within the pigment. These microdomains represent the first visualization of a structure regulating the metal-binding properties of NM and supporting a physiological role for NM in the regulation of functionally important elements in pigmented neurons. Our results demonstrate that the local chemical environment of iron in NM is similar to that found in ferritin and points to a possible role of iron in NM biosynthesis. Intracellular speciation of sulfur contained in NM revealed the presence of reduced sulfur compounds and various forms of oxidized sulfur compounds which have not previously been reported. Further, a significant increase in sulfonate in NM in the mature brain suggests that in vivo metabolism of the pigment via an as yet unidentified pathway occurs. The current data add to our understanding of the development and regulation of NM in the human brain.
| 19,007,186
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C-H bond activation of heteroarenes mediated by a half-sandwich iron complex of N-heterocyclic carbene.
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Half-sandwich iron complexes of N-heterocyclic carbenes, Cp*Fe(L(R))Cl (2a; L(Mes) = 1,3-dimesityl-imidazol-2-ylidene, 2b; L(iPr) = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene, Cp* = eta(5)-C5Me5), have been synthesized by the reaction of Cp*Fe{N(SiMe3)2} (1) with the corresponding imidazolium salts. Treatment of 2a with either methyllithium or phenyllithium replaces the chloride with either a methyl or a phenyl group, generating Cp*Fe(L(Mes))R (3a; R = Me, 3b; R = Ph). These complexes, in turn, undergo cyclometalation at elevated temperatures, and Cp*Fe{kappa2-(C,C)-L'(Mes)} (4; L'(Mes) = CH2C6H2-3,5-Me2-2-(3-mesityl-imidazol-2-ylidene-1-yl)) was isolated. On the other hand, methylation of 2b at room temperature leads directly to the formation of a cyclometalated complex, Cp*Fe{kappa2-(C,C)-L'(iPr)} (6; L'(iPr) = CH2CH(CH3)(3-isopropyl-4,5-dimethylimidazol-2-ylidene-1-yl)). The Fe(II) center of 6 traps atmospheric dinitrogen reversibly to produce a dinuclear end-on N2 complex [Cp*Fe{kappa2-(C,C)-L'(iPr)}]2(mu-eta(1):eta(1)-N2) (7). Complex 6 also promotes C-H bond activation of thiophene, furan, benzothiophene, and benzofuran at room temperature. In these reactions, C-H bond cleavage occurred exclusively at the 2-position of the rings, generating Cp*Fe(L(iPr))(2-C4H3E) (8; E = S, 9; E = O) and Cp*Fe(L(iPr))(2-C8H5E) (10; E = S, 11; E = O), while C-H cleavage took place mainly at the 4-position in the case of pyridine. Coupling reactions between heteroarenes and catecholborane (HBcat) can be carried out by treatment of 6 with heteroarenes followed by the addition of excess HBcat, giving rise to 2-boryl-heteroarenes and the borohydride complex Cp*Fe(L(iPr))(H2Bcat) (14).
| 19,007,215
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A tunable photosensor.
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A pyrene-modified beta-cyclodextrin (pyrenecyclodextrin)-decorated single-walled carbon nanotube (SWNT) field-effect transistor (FET) device was fabricated, which can serve as a tunable photosensor to sense a fluorescent adamantyl-modified Ru complex (ADA-Ru). When the light is on (I = 40 W m(-2) and lambda = 280 nm), the transfer curve of the pyrenecyclodextrin-SWNT/FET device shifts toward a negative gate voltage by about 1.6 V and its sheet resistance increases quickly, indicating a charge-transfer process from the pyrenecyclodextrins to the SWNTs. In contrast, the transfer curve of the pyrenecyclodextrin-SWNT/FET device in the presence of the ADA-Ru complex shifts toward a positive gate voltage by about 1.9 V and its sheet resistance decreases slowly when the light is on (I = 40 W m(-2) and lambda = 490 nm), showing a charge-transfer process from the pyrenecyclodextrin-SWNT hybrids to the ADA-Ru complex. Because these photoresponse processes are recoverable following the removal of the light, the present photosensor exhibits a promising application in the area of tunable light detection.
| 19,007,219
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Intestinal and peripheral immune response to MON810 maize ingestion in weaning and old mice.
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This study evaluated the gut and peripheral immune response to genetically modified (GM) maize in mice in vulnerable conditions. Weaning and old mice were fed a diet containing MON810 or its parental control maize or a pellet diet containing a GM-free maize for 30 and 90 days. The immunophenotype of intestinal intraepithelial, spleen, and blood lymphocytes of control maize fed mice was similar to that of pellet fed mice. As compared to control maize, MON810 maize induced alterations in the percentage of T and B cells and of CD4(+), CD8(+), gammadeltaT, and alphabetaT subpopulations of weaning and old mice fed for 30 or 90 days, respectively, at the gut and peripheral sites. An increase of serum IL-6, IL-13, IL-12p70, and MIP-1beta after MON810 feeding was also found. These results suggest the importance of the gut and peripheral immune response to GM crop ingestion as well as the age of the consumer in the GMO safety evaluation.
| 19,007,233
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Total synthesis of (-)-2-epi-peloruside A.
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A convergent synthesis of (-)-2-epi-peloruside A has been achieved. Highlights include implementation of multicomponent type I anion relay chemistry (ARC) to unite 2-TBS-1,3-dithiane with two epoxides to construct the eastern hemisphere, a late-stage dithiane union to secure the complete, fully functionalized carbon backbone, and Yamaguchi macrolactonization, which led to (-)-2-epi-peloruside A via an unexpected epimerization at C(2).
| 19,007,239
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Self-assembly of nanodonut structure from a cone-shaped designer lipid-like peptide surfactant.
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We report here the donut-shaped nanostructure formation from the self-assembly of a designer lipid-like amphiphilic cone-shaped peptide. The critical aggregation concentration was measured using dynamic light scattering in water and phosphate-buffered saline. The dynamic self-assembly of the peptide was also studied using atomic force microscopy. We have studied numerous peptides over 17 years, and this is the first time that we have ever observed the nanodonut structure from cone-shaped peptides. We propose a plausible self-assembling pathway of the nanodonut structure that was self-assembled through the fusion or elongation of spherical micelles. Furthermore, the bending of the nanostructure gives rise to the nanodonut structures as a result of the tension originating from the interaction of the cone-shaped peptide side chains. Our observations may be useful for further fine tuning the geometry and shape of a new class of designer peptides and their self-assembled supramolecular materials for diverse uses.
| 19,007,256
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Protease-specific nanosensors for magnetic resonance imaging.
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Imaging of enzyme activity is a central goal of molecular imaging. With the introduction of fluorescent smart probes, optical imaging has become the modality of choice for experimental in vivo detection of enzyme activity. Here, we present a novel high-relaxivity nanosensor that is suitable for in vivo imaging of protease activity by magnetic resonance imaging. Upon specific protease cleavage, the nanoparticles rapidly switch from a stable low-relaxivity stealth state to become adhesive, aggregating high-relaxivity particles. To demonstrate the principle, we chose a cleavage motif of matrix metalloproteinase 9 (MMP-9), an enzyme important in inflammation, atherosclerosis, tumor progression, and many other diseases with alterations of the extracellular matrix. On the basis of clinically tested very small iron oxide particles (VSOP), the MMP-9-activatable protease-specific iron oxide particles (PSOP) have a hydrodynamic diameter of only 25 nm. PSOP are rapidly activated, resulting in aggregation and increased T2*-relaxivity.
| 19,007,261
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Designing temperature-responsive biocompatible copolymers and hydrogels based on 2-hydroxyethyl(meth)acrylates.
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Free-radical copolymerization of 2-hydroxyethyl methacrylate with 2-hydroxyethyl acrylate can be successively utilized for the synthesis of water-soluble polymers and hydrogels with excellent physicochemical properties, thus showing promise for pharmaceutical and biomedical applications. In the work presented it has been demonstrated that water-soluble copolymers based on 2-hydroxyethyl methacrylate and 2-hydroxyethyl acrylate exhibit lower critical solution temperature in aqueous solutions, whereas the corresponding high molecular weight homopolymers do not have this unique property. The temperature-induced transitions observed upon heating the aqueous solutions of these copolymers proceed via liquid-liquid phase separation. The hydrogels were also synthesized by copolymerizing 2-hydroxyethyl methacrylate and 2-hydroxyethyl acrylate in the absence of a bifunctional cross-linker. The cross-linking of these copolymers during copolymerization is believed to be due to the presence of bifunctional admixtures or transesterification reactions. Transparency, swelling behavior, mechanical properties, and porosity of the hydrogels are dependent upon the monomer ratio in the copolymers. Hydrogel samples containing more 2-hydroxyethyl methacrylate are less transparent, have lower swelling capacity, higher elastic moduli, and pores of smaller size. The assessment of the biocompatibility of the copolymers using the slug mucosal irritation test revealed that they are also less irritant than poly(acrylic acid).
| 19,007,281
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Isoflavonoid glycosides from the roots of Baphia bancoensis.
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Chemical investigation of the methanol extract of the roots of Baphia bancoensis led to the isolation and characterization of three new isoflavonoid glycosides (1-3). Their structures were determined on the basis of spectroscopic studies andchemical evidence. Antibacterial activity of isolated compounds was evaluated against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa.
| 19,007,285
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Antileishmanial constituents of the Panamanian endophytic fungus Edenia sp.
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Bioassay-directed fractionation of extracts from the fermentation broth and mycelium of the fungus Edenia sp. led tothe isolation of five antileishmanial compounds, preussomerin EG1 (1), palmarumycin CP2 (2), palmarumycin CP17 (3), palmarumycin CP18 (4), and CJ-12,371 (5). Compounds 3 and 4 are new natural products, and this is only the second report of compound 1. The structures of compounds 1-5 were established by spectroscopic analyses (HRMS and NMR). All metabolites caused significant inhibition of the growth of Leishmania donoVani in the amastigote form, with IC50 values of 0.12, 3.93, 1.34, 0.62, and 8.40 microM, respectively. Compounds 1-5 were inactive when tested against Plasmodium falciparum or Trypanasoma cruzi at a concentration of 10 microg/mL, indicating that they have selective activity against Leishmania parasites. Compounds 1-5 showed weak cytotoxicity to Vero cells (IC50 of 9, 162, 174, 152, and 150 microM, respectively); however, the therapeutic window of these compounds is quite significant with 75, 41, 130, 245, and 18 times (respectively) more antileishmanial activity than cytotoxicity.
| 19,007,286
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Gross placental structure in a low-risk population of singleton, term, first-born infants.
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Suboptimal fetal growth has been associated with an increased risk of adult disease, which may be exacerbated by an increased placental weight-to-fetal weight ratio. Placental weight is a summary measure of placental growth and development throughout pregnancy. However, measures of placental structure, including the chorionic disk surface area and thickness and eccentricity of the umbilical cord insertion, have been shown to account for additional variance in birth weight beyond that explained by placental weight. Little is known of the variability of these placental parameters in low-risk populations; their association with maternal, pregnancy, and neonatal characteristics; and the agreement between manual and digital measures. This study used manual and digital image analysis techniques to examine gross placental anatomy in 513 low-risk, singleton, term, first-born infants. Parametric methods compared groups and examined relationships among variables. Maternal birth weight, prepregnancy weight, and body mass index were associated with increased placental and birth weight (all P < 0.005), but only maternal birth weight was associated with increased placental surface area (P < 0.0005) and thickness (P = 0.005). Smoking during pregnancy reduced birth weight and increased the eccentricity of umbilical cord insertion (P = 0.012 and 0.034, respectively). The variability in these placental parameters was consistently lower than that reported in the literature, and correlations between digital and manual measurements were reasonable (r = .87-.71). Detailed analyses of gross placental structure can provide biologically relevant information regarding placental growth and development and, potentially, their consequences.
| 19,007,303
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Current and emerging paradigms in the therapeutic management of atherosclerosis.
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The pathogenesis of atherosclerosis lies in abnormalities in lipoprotein metabolism leading to pathological interactions with vessel walls and the release of inflammatory components, which further aggravate the disease condition. To elucidate current and emerging trends in drug discovery towards the development of new entities regulating lipoprotein metabolism and inflammatory components to combat the progression of atherosclerosis. Research/review articles in the public domain and press releases were employed. With the recent failure of torcetrapib and succinobucol, drug discovery and development efforts towards the treatment of atherosclerosis have received a big jolt and have been slowed down to a certain extent [corrected]. But this could be a starting point for several new mechanisms that are emerging to discover new drugs to combat the disease.
| 19,007,321
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Mast cells in health and disease: from basic science to clinical application 4-5 July 2008, Stuttgart, Germany.
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In July 2008, the fifth and last meeting of the Mast Cells and Chronic Inflammatory Diseases (MCCID) network was hosted by Axel Lorentz and Stephan Bischoff at the University of Hohenheim, in the Aula of the Chateau Hohenheim, Stuttgart. The MCCID initiative is a Marie Curie early stage research training (EST)-sponsored multi-partner project that fosters collaboration between fundamental research, clinics and industry. At the same time, this meeting was the founding meeting of the new European Mast Cell Research Network (EMCRN) initiated by SC Bischoff, U Blank, F Levi-Schaffer, M Mauer and G Nielsson (steering committee), in co-operation with P Valent from the European Competence Network on Mastocytosis (ECNM). A mixture of scientists from pharma, biotech and academic institutions attended the meeting, presenting recent data from the field with a special focus on novel therapeutic strategies and possible interactions between industry and research. The aim of this report is to briefly describe some of the most intriguing of these new findings and to discuss how they can be relevant for making use of mast cells as therapeutic targets.
| 19,007,326
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A-overhang-dependent repeat expansion determination (ADRED).
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In this study we present a quick and easy method for counting trinucleotide repeats by de-oxyadenosine overhang (A-overhang)-dependent repeat expansion determination (ADRED). During standard Taq DNA polymerase-based sequencing reactions, the unterminated sequencing products of short PCR fragments are tagged with a 3'-end A-overhang that is visible as an intense peak in an electropherogram; this allows for easy and precise determination of the fragment length and thus the extent of repeat expansions. ADRED has clear advantages over existing methods, because repeat numbers of both normal and pathogenic (expanded) alleles can be analyzed without using labeled primers or labeled DNA standards. Because ADRED includes a sequencing step, disease-relevant polymorphisms (e.g., CAA interruptions in spinocerebellar ataxia type 2) can simultaneously be detected.
| 19,007,342
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Ovarian structure in mice lines selected for weight.
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Selection for body weight at 49 day of age (s and h, downward selected lines; s' and h', upward selected lines) affected reproductive traits in CF1 mice lines. The objective of this study was to compare ovarian structures in females of these lines, as well as in unselected controls (Line t). The number of ovarian follicles (N), follicle diameter (FD), number of corpora lutea (CL), litter size (LS), and body weight (W), were recorded. There were significant differences among lines for N, FD, CL, LS and W; means values for the lines with the greatest difference for post-pubertal females were: N(s) = 19.3 and N(s') = 32.7; FD(h') = 161.7 and FD(s') = 178.2; CL(h) = 10.3 and CL(s') = 21.9; LS(s) = 6.0 and LS(h') = 11.1; W(h) = 18.9 and W(s') = 32.4. There were also differences between positive lines; Line s' had a higher proportion of large follicles in pre-pubertal females, a greater capacity to convert these follicles into CL, but a lower capacity to maintain embryos until term than Line h'. For negative lines, Line h apparently had a reduced incidence of embryonic loss when compared with Line s. In conclusion, selection for body weight modified ovarian structure, as well as reproductive efficiency.
| 19,007,351
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Gross anatomy of the female genital organs of the domestic donkey (Equus asinus Linné, 1758).
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Although donkeys play an important role as companion or pack and draught animals, theriogenological studies and anatomical data on the genital organs of the jenny are sparse. To provide anatomical descriptions and morphometric data, the organa genitalia feminina, their arteries and the ligamentum latum uteri of 10 adult but maiden jennies were examined by means of gross anatomical and morphometric techniques. In comparison with anatomical data of horses obtained from literature the genital organs of jennies appear to be more voluminous in relation to the body mass and the position of the ovaries is slightly further cranial than in mares. In asses, the ovaries contain large follicles reaching a diameter of up to 40 mm. The mesosalpinx is much wider than in the horse forming a considerably spacious bursa ovarica. The asinine ligamentum teres uteri reveals a very prominent cranial end, the 'appendix'. Tortuous mucosal folds occur in the wall of the jenny's cervical channel. The vascularization of the female genital organs of asses is very similar to that of horses. One of the examined specimens reveals a large mucosal fold dividing the cranial part of the vagina into a left and right compartment.
| 19,007,353
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Paclitaxel incorporated in hydrophobically derivatized hyperbranched polyglycerols for intravesical bladder cancer therapy.
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To develop paclitaxel incorporated into unimolecular micelles based on hydrophobically derivatized hyperbranched polyglycerols (dHPGs) for use as mucoadhesive intravesical agents against non-muscle-invasive bladder cancer. Two different types of dHPGs (HPG- C10-polyethylene glycol (PEG) and polyethyleneimine (PEI)-C18-HPG) were synthesized and paclitaxel was loaded into these using a solvent evaporation method. After physicochemical characterization of the resulting nanoparticles, four human bladder cancer cell lines were incubated with various concentrations of paclitaxel incorporated in dHPGs and the results were compared with those of paclitaxel formulated in Cremophor-EL (Taxol(R), Bristol-Myers-Squibb). In vivo, nude mice with orthotopic KU7-luc tumours were intravesically instilled with phosphate buffered saline, Taxol, or paclitaxel/HPG-C10-PEG. dHPGs are mucoadhesive nanoparticles with hydrodynamic radii of <10 nm and incorporation of paclitaxel did not affect their size. The release profiles of paclitaxel from dHPGs were characterized by a rapid-release phase followed by a slower sustained-release phase. While the PEI-C18-HPG formulation released only approximately 40% of the initially incorporated paclitaxel, up to 80% was released from HPG-C10-PEG. Moreover, only paclitaxel/HPG-C10-PEG was stable in acidic urine. In vitro, all paclitaxel formulations potently decreased bladder cancer proliferation although paclitaxel/HPG-C10-PEG was slightly less cytotoxic than standard Taxol. By contrast, in vivo, the mucoadhesive HPG-C10-PEG formulation of paclitaxel was significantly more effective in reducing orthotopic tumour growth than Taxol and was well tolerated. Intravesical administration of mucoadhesive nanoparticulate formulations of paclitaxel might be a promising approach for instillation therapy of patients with non-muscle-invasive bladder cancer.
| 19,007,363
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Is the body mass index a predictor of adverse outcome in prostate cancer after radical prostatectomy in a mid-European study population?
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To evaluate the effect of body mass index (BMI) on the histopathological and clinical outcome in prostate cancer. In a prospective urological cancer database, 620 patients with prostate cancer had a radical prostatectomy (RP) as a curative treatment. The patients were categorized into three groups of BMI (kg/m(2)); <or=25.0 (190, 'normal weight'), >25.0-30.0 (343, 'overweight') and >30.0 (87, 'obese'). We evaluated the histopathological features and the clinical follow-up after RP. The median (range) age of the men was 64.4 (41.1-80.1) years and the median follow-up 5.5 (0.1-15.1) years. The preoperative median prostate-specific antigen (PSA) levels for normal, overweight and obese patients were 9.0 (0.3-133.0), 8.9 (0.4-230.0) and 9.2 (0.5-194.0) ng/mL, respectively. Serum PSA levels were no different among the three groups (P = 0.92). The normal, overweight and obese patients had organ-confined prostate cancer in 53.7%, 57.1% and 58.6%, respectively (P = 0.34) and had lymph node metastases in 7.9%, 7.6% and 4.6% (P = 0.58). Tumour grading was no different for the three groups (P = 0.25). The PSA recurrence-free, prostate cancer-specific and overall survival for the three BMI groups did not differ significantly (each P > 0.05). The BMI cannot be shown to be a predictor of adverse prognosis either for histopathological features or for the clinical outcome, e.g. PSA-free, prostate cancer-specific and overall survival, in a mid-European study population after RP.
| 19,007,372
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Research on rural veterans: an analysis of the literature.
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The Veterans Health Administration (VA) provides comprehensive health care services to veterans across the United States. Recently, the VA established an Office of Rural Health to address the health care needs of rural veterans. To review the literature on rural veterans' health care needs in order to identify areas for future research. We conducted a literature review of articles listed in the Medline, CINAHL, and BIOSIS datasets since 1950. We reviewed and summarized the findings of 50 articles that specifically examined rural veterans. The literature on rural veterans included 4 articles examining access to care, 7 evaluating distance technology, 4 examining new models of care delivery, 11 studying rural veterans' patient characteristics, 10 evaluating programs provided in a rural setting, 6 examining rural health care settings, and 8 exploring rural veterans' health services utilization patterns. Most studies were small, based on data obtained before 2000, and consisted of uncontrolled, retrospective, descriptive studies of health care provided in rural VA settings. Definitions of rural were inconsistent, and in 20% of the articles examined the rural aspect of the setting was incidental to the study. The literature on rural veterans' health care needs warrants expansion and investment so that policy makers can make informed decisions in an environment of limited resources and competing interests.
| 19,007,387
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A contract-based training system for rural physicians: follow-up of Jichi Medical University graduates (1978-2006).
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The number of studies on long-term effects of rural medical education programs is limited. Personal factors that are associated with long-term retention of physicians in rural areas are scarcely known. The authors studied the outcomes of Jichi Medical University (JMU), whose mission is to produce rural doctors, and analyzed the characteristics of its graduates who engaged in rural practice even after their 9-year obligation of rural practice. A retrospective cohort study was conducted including 2,988 JMU students who graduated between 1978 and 2006. Baseline data were collected at matriculation and graduation. Workplace addresses were surveyed in 2000, 2004, and 2006. Follow-up rates were 98.7%, 98.2%, and 98.0% respectively. After their obligation period, JMU graduates were 4 times more likely than non-JMU graduates to work in rural areas. The higher proportion of JMU graduates in rural areas did not change significantly between 1994 and 2004. The rural recruitment rate of post-obligation JMU graduates was somewhat lower than rates reported for top rural medical education programs in the United States. In multivariate analyses, rural upbringing and primary care specialty were positively associated with having a rural address in at least one post-obligation study year (OR 1.89 [95% CI 1.27-2.81]; and 7.63 [4.37-13.34], respectively) and settlement (ie, having a rural address over multiple years) after the contract (1.90 [1.04-3.48]; and 32.07 [4.43-232.24], respectively). Graduation from a private high school had a negative association with recruitment (0.56 [0.33-0.96]). JMU was successful in increasing the number and retention of rural physicians. Rural origin and primary care specialty have a positive impact on both recruitment and retention after the rural obligation.
| 19,007,390
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Aspergillus nidulans FlbE is an upstream developmental activator of conidiation functionally associated with the putative transcription factor FlbB.
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Aspergillus nidulans switches from vegetative growth to conidiation when aerial hyphae make contact with the atmosphere, or are subjected to specific environmental stress. The activation of the central conidiation pathway led by the transcription factor brlA is a critical milestone in this morphogenetic transition. A number of upstream developmental activators (UDAs), expressed in vegetative cells, are required for this process to occur in conjunction with cessation of vegetative growth. Mutants affected in these factors remain aconidial (fluffy) with low brlA expression levels (flb). In this report, we describe FlbE as a UDA containing two conserved but hitherto uncharacterized domains, which functions in close association with putative transcription factor FlbB. Both UDAs are functionally interdependent, and colocalize at the hypha tip in an actin cytoskeleton-dependent manner. Moreover, bimolecular fluorescence studies show that they physically interact in vivo. These findings add evidence in favour of the existence of a signalling complex at or near the Spitzenkörper as an important part of the machinery controlling the morphogenetic transition between vegetative growth and conidiation.
| 19,007,409
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Of blood, brains and bacteria, the Amt/Rh transporter family: emerging role of Amt as a unique microbial sensor.
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Members of the Amt/Rh family of transporters are found almost ubiquitously in all forms of life. However, the molecular state of the substrate (NH(3) or NH(4)(+)) has been the subject of active debate. At least for bacterial Amt proteins, the model emerging from computational, X-ray crystal and mutational analysis is that NH(4)(+) is deprotonated at the exterior, conducted through the membrane as NH(3), and reprotonated at the cytoplasmic interface. A proton concomitantly is transferred from the exterior to the interior, although the mechanism is unclear. Here we discuss recent evidence indicating that an important function of at least some eukaryotic and bacterial Amts is to act as ammonium sensors and regulate cellular metabolism in response to changes in external ammonium concentrations. This is now well documented in the regulation of yeast pseudohyphal development and filamentous growth. As well, membrane sequestration of GlnK, a PII signal transduction protein, by AmtB has been shown to regulate nitrogenase in some diazotrophs, and nitrogen metabolism in some gram-positive bacteria. Formation of GlnK-AmtB membrane complexes might have other, as yet undiscovered, regulatory roles. This possibility is emphasized by the discovery in some genomes of genes for chimeric Amts with fusions to various regulatory elements.
| 19,007,411
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Loss of Hda activity stimulates replication initiation from I-box, but not R4 mutant origins in Escherichia coli.
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Initiation of chromosome replication in Escherichia coli is limited by the initiator protein DnaA associated with ATP. Within the replication origin, binding sites for DnaA associated with ATP or ADP (R boxes) and the DnaA(ATP) specific sites (I-boxes, tau-boxes and 6-mer sites) are found. We analysed chromosome replication of cells carrying mutations in conserved regions of oriC. Cells carrying mutations in DnaA-boxes I2, I3, R2, R3 and R5 as well as FIS and IHF binding sites resembled wild-type cells with respect to origin concentration. Initiation of replication in these mutants occurred in synchrony or with slight asynchrony only. Furthermore, lack of Hda stimulated initiation in all these mutants. The DnaA(ATP) containing complex that leads to initiation can therefore be formed in the absence of several of the origin DnaA binding sites including both DnaA(ATP) specific I-boxes. However, competition between I-box mutant and wild-type origins, revealed a positive role of I-boxes on initiation. On the other hand, mutations affecting DnaA-box R4 were found to be compromised for initiation and could not be augmented by an increase in cellular DnaA(ATP)/DnaA(ADP) ratio. Compared with the sites tested here, R4 therefore seems to contribute to initiation most critically.
| 19,007,419
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Repression of galP, the galactose transporter in Escherichia coli, requires the specific regulator of N-acetylglucosamine metabolism.
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Soupene et al. [J. Bacteriol. (2003) 185 5611-5626] made the unexpected observation that the presence of a mutation, in the gene for the N-acetylglucosamine repressor, nagC, increased the growth rate of Escherichia coli MG1655 on galactose, an unrelated sugar. We have found that NagC, binds to a single, high-affinity site overlapping the promoter of galP (galactose permease) gene and that expression of galP is repressed by a combination of NagC, GalR and GalS. In addition to the previously identified galOE operator, other gal operators further upstream are required for full repression. GalS has a specific role, as it binds with higher affinity to one of the upstream operators but its effect in vivo is only observed in the presence of GalR. Regulation of galP by three specific repressors, NagC, GalR and GalS is unusual in that it involves multiple, specific regulators from two different areas of metabolism. This novel regulation seems to be particular for E. coli and its nearest neighbour, Shigella. Other bacteria with galP orthologues, although retaining the metK-galP gene order, do not have the NagC site. Although quantitative effects were strain specific, nagC mutations increased the growth rate on galactose of all E. coli strains tested.
| 19,007,420
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Targeting the UPS as therapy in multiple myeloma.
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The coordinated regulation of cellular protein synthesis and degradation is essential for normal cellular functioning. The ubiquitin proteasome system mediates the intracellular protein degradation that is required for normal cellular homeostasis. The 26S proteasome is a multi-enzyme protease that degrades redundant proteins; conversely, inhibition of proteasomal degradation results in intracellular aggregation of unwanted proteins and cell death. This observation led to the development of proteasome inhibitors as therapeutics for use in cancer. The clinical applicability of targeting proteasomes is exemplified by the recent FDA approval of the first proteasome inhibitor, bortezomib, for the treatment of relapsed/refractory multiple myeloma. Although bortezomib represents a major advance in the treatment of this disease, it can be associated with toxicity and the development of drug resistance. Importantly, extensive preclinical studies suggest that combination therapies can both circumvent drug resistance and reduce toxicity. In addition, promising novel proteasome inhibitors, which are distinct from bortezomib, and exhibit equipotent anti-multiple myeloma activities, are undergoing clinical evaluation in order to improve patient outcome in multiple myeloma. PUBLICATION HISTORY : Republished from Current BioData's Targeted Proteins database (TPdb; http://www.targetedproteinsdb.com).
| 19,007,431
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Two-dimensional imaging of water vapor by near-infrared laser absorption spectroscopy.
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Both a flow of water vapor generated from a humidification device and stable water vapor at constant moisture were successfully visualized by near-infrared (NIR) laser absorption spectroscopy. Two different types of optical arrangement for two-dimensional (2D) imaging, i.e., one-wavelength reflection and two-wavelength transmission, were tested. A flow of water vapor within a wide view range was clearly visualized by the former, while low content of stable water vapor was quantitatively detected by the latter. It was demonstrated that a detection limit of 0.8 g.m(-3) was achieved by means of the 2D-NIR imaging system developed in the present study.
| 19,007,462
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Spectroscopic properties of some derivatives of polycyclic aromatic hydrocarbons.
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The aim of this paper is to provide a general picture of the spectral characteristics of some polycyclic aromatic hydrocarbon (PAH) derivatives. A great deal of data concerning PAHs has been reported in the literature, but there is lack of comprehensiveness about important parameters in the same experimental conditions for their nitro (NO(2)) and amino (NH(2)) derivatives such as absorption and emission characteristics. Thus, important parameters such as the molar extinction coefficient, absorption maxima, fluorescence maxima, and fluorescence quantum yield are reported here. The efficiencies of the reduction of NO(2)-PAHs to their corresponding amino compounds were also verified by means of high-performance liquid chromatography (HPLC). This class of derivatives represents one of the most toxic groups of carcinogenic substances and therefore the data reported here should be useful for toxicological research.
| 19,007,465
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Spectroscopic study on the enhanced excitation of an electron cyclotron resonance nitrogen plasma by pulsed laser ablation of an aluminum target.
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The influence of pulsed laser ablation of an aluminum target on the nitrogen plasma produced by electron cyclotron resonance (ECR) microwave discharge has been studied by optical emission spectroscopy (OES) with time and space resolution. The continuous wave (CW) feature of the optical emissions from the ECR nitrogen plasma turns to vary with time and space due to pulsed laser ablation and the expansion of the ablation-induced aluminum plume in the nitrogen plasma. The optical emissions from the nitrogen plasma increase significantly and the emission intensity of nitrogen molecular ions is observed to be more than 20 times higher with the target being ablated in comparison to the case without target ablation. The comparison of the optical emissions from the nitrogen plasma with those from the aluminum plume indicates that the excitation enhancement of the nitrogen plasma occurs in the region where the aluminum plume is expanding, revealing that the expansion of the aluminum plume leads to the excitation enhancement of the nitrogen plasma. Relevant mechanisms responsible for the excitation enhancement of the nitrogen plasma through hybrid processes of ECR microwave discharge and pulsed laser ablation are also discussed.
| 19,007,469
|
Preparation and chiral recognition of a mono[6A-N-1-(2-hydroxy)-phenylethylimino-6A-deoxy]-beta-cyclodextrin HPLC stationary phase.
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A novel chiral stationary phase (CSP) is obtained by linking the beta-CD to a chiral block (commercially available phenylglycinol) by rigid C=N bond. This chiral stationary phase exhibites good enantioselectivity for several alkylaromatic alcohols and a variety of ferrocene derivatives under reversed-phase conditions, with the best Rs value achieve up to 6.19. The hydrogen bonding interaction may be the primary factor, also pi-pi interaction or dipole-dipole interaction has some effect on chiral separation. The dependence of the natural logarithms of retention and selectivity factors (lnk' and lnalpha) on the inverse of temperature 1/T (van't Hoff plots) is used to determine thermodynamic data referring to the separation of the enantiomers. Calculated thermodynamic constants Delta(DeltaH degrees ), Delta (DeltaS degrees ), and Delta (DeltaG degrees ) are applied to help understand of the thermodynamic driving forces for retention and enantio-recognition for this chromatographic system. It can be concluded that the separations for all the investigated analytes on this CSP are enthalpically favored.
| 19,007,478
|
The chiral separation of triazole pesticides enantiomers by amylose-tris (3,5-dimethylphenylcarbamate) chiral stationary phase.
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The amylose-tris(3,5-dimethylphenylcarbamate) chiral stationary phase was synthesized and used to separate the enantiomers of triazole pesticides by high-performance liquid chromatography. The mobile phase was n-hexane-isopropanol applying a flow rate of 1.0 mL/min. Six triazole pesticides were enantioselectively separated. Myclobutanil, paclobutrazol, tebuconazole, and uniconazole obtained complete separation with the resolution factors of 5.73, 2.99, 1.72, and 2.07, respectively, and imazalil and diniconazole obtained partial separation with the resolution factors of 0.79 and 0.77 under the optimized conditions. The effect of the content of isopropanol as well as column temperature on the separation was investigated. A circular dichroism detector was used to identify the enantiomers and determine the elution orders. The results showed the low temperature was good for the chiral separation except for diniconazole. The thermodynamic parameters calculated based on linear Van't Hoff plots showed the chiral separations were controlled by enthalpy.
| 19,007,480
|
Quantitative determination of atorvastatin and para-hydroxy atorvastatin in human plasma by LC-MS-MS.
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A specific, sensitive, and fast method based on high-performance liquid chromatography coupled to tandem mass spectrometry was developed for the determination of atorvastatin and para-hydroxy atorvastatin in human plasma. Solid-phase extraction was used to isolate the compounds from human plasma followed by injection of the extracts onto a C18 column with isocratic elution. The lower limits of quantitation was 0.229 and 0.202 ng/mL for atorvastatin and para-hydroxy atorvastatin in human plasma, respectively. The method was then successfully applied to the pharmacokinetic study of atorvastatin in healthy Chinese male subjects.
| 19,007,492
|
Simultaneous determination of theobromine, (+)-catechin, caffeine, and (-)-epicatechin in standard reference material baking chocolate 2384, cocoa, cocoa beans, and cocoa butter.
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A reverse-phase liquid chromatography analysis is used to access the quantity of theobromine, (+)-catechin, caffeine, and (-)-epicatechin in Standard Reference Material 2384 Baking Chocolate, cocoa, cocoa beans, and cocoa butter using water or a portion of the mobile phase as the extract. The procedure requires minimal sample preparation. Theobromine, (+)-catechin, caffeine, and (-)-epicatechin are detected by UV absorption at 273 nm after separation using a 0.3% acetic acid-methanol gradient (volume fractions) and quantified using external standards. The limit of detection for theobromine, (+)-catechin, caffeine, and (-)-epicatechin averages 0.08, 0.06, 0.06, and 0.06 microg/mL, respectively. The method when applied to Standard Reference Material 2384 Baking Chocolate; baking chocolate reference material yields results that compare to two different, separate procedures. Theobromine ranges from 26000 mg/kg in cocoa to 140 mg/kg in cocoa butter; (+)-catechin from 1800 mg/kg in cocoa to below detection limits of < 32 mg/kg in cocoa butter; caffeine from 2400 mg/kg in cocoa to 400 mg/kg in cocoa butter, and (-)-epicatechin from 3200 mg/kg in cocoa to BDL, < 27 mg/kg, in cocoa butter. The mean recoveries from cocoa are 102.4 +/- 0.6% for theobromine, 100.0 +/- 0.6 for (+)-catechin, 96.2 +/- 2.1 for caffeine, and 106.2 +/- 1.7 for (-)-epicatechin.
| 19,007,497
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Urinary elimination of 11-nor-9-carboxy-delta9-tetrahydrocannnabinol in cannabis users during continuously monitored abstinence.
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The time course of 11-nor-9-carboxy-Delta9-tetrahydrocannnabinol (THCCOOH) elimination in urine was characterized in 60 cannabis users during 24 h monitored abstinence on a closed research unit for up to 30 days. Six thousand, one hundred fifty-eight individual urine specimens were screened by immunoassay with values > or = 50 ng/mL classified as positive. Urine specimens were confirmed for THCCOOH by gas chromatography-mass spectrometry following base hydrolysis and liquid-liquid or solid-phase extraction. In 60%, the maximum creatinine normalized concentration occurred in the first urine specimen; in 40%, peaks occurred as long as 2.9 days after admission. Data were divided into three groups, 0-50, 51-150, and > 150 ng/mg, based on the creatinine corrected initial THCCOOH concentration. There were statistically significant correlations between groups and number of days until first negative and last positive urine specimens; mean number of days were 0.6 and 4.3, 3.2 and 9.7, and 4.7 and 15.4 days, respectively, for the three groups. These data provide guidelines for interpreting urine cannabinoid test results and suggest appropriate detection windows for differentiating new cannabis use from residual drug excretion.
| 19,007,504
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Quantitation of benzodiazepines in whole blood by electron impact-gas chromatography-mass spectrometry.
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Benzodiazepines are frequently encountered in forensic toxicology. A literature search was conducted to find a simple method using electron impact-gas chromatography-mass spectrometry (EI-GC-MS) to examine whole blood specimens for the most commonly encountered benzodiazepines in the United States. A recently published method was identified in the literature search and used as a starting point for development of a new procedure to be used for routine analysis of forensic toxicology case samples. The procedure was then developed and validated as a rapid and efficient method for the screening and quantitation of benzodiazepines in blood using liquid-liquid extraction and EI-GC-MS in selective ion monitoring mode. Materials and instrumentation common to most forensic toxicology laboratories were utilized while obtaining LODs from 5 to 50 ng/mL and LOQs of 50 ng/mL or less using 1 mL of sample. Target compounds were chosen based on availability and common use in the United States and include diazepam, desalkylflurazepam, nordiazepam, midazolam, oxazepam, temazepam, lorazepam, clonazepam, and alprazolam (relative elution order). The linear range (r2 > 0.990) was validated from 50 to 1000 ng/mL for all analytes. The CV of replicate analyses at both 50 and 200 ng/mL was less than 4%. Quantitative accuracy was within +/- 16% at 50 ng/mL and within +/- 7% at 200 ng/mL. The validated method provides an efficient procedure for the quantitation of a broad range of the most common benzodiazepines in blood at meaningful limits of detection and quantitation using standard laboratory equipment and a small amount of sample.
| 19,007,516
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Free oxycodone concentrations in 67 postmortem cases from the Hennepin County medical examiner's office.
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Heart blood free oxycodone concentrations in oxycodone-related and mixed drug overdose deaths were compared with those found incidentally at autopsy in medical examiner cases. Between 2000 and 2005, 67 oxycodone-positive postmortem cases were identified. Thirty of 67 cases (44.8%) were determined to be drug overdoses. Oxycodone alone was responsible for 7 of the 30 (23.3%) overdose deaths. Mean (median) oxycodone concentrations were 1.060 mg/L (0.824 mg/L) with a range of 0.270-3.390 mg/L. Three cases were accidents, three were suicides, and one was undetermined. The remaining 23 were mixed drug overdoses. Mean (median) oxycodone concentrations in these cases were 0.820 mg/L (0.470 mg/L) with a range of 0.014-3.800 mg/L. Sixteen mixed drug overdoses were accidental, and seven were suicidal. Where oxycodone was an incidental finding, 24 were natural, 6 accident, 4 suicide, 1 homicide, and 2 undetermined. The mean (median) concentrations in the incidental finding group were 0.330 mg/L (0.150 mg/L) with a range of 0.017-1.300 mg/L. In conclusion, the findings substantiate the considerable overlap that exists with blood oxycodone concentrations in cases where oxycodone alone was determined to be the cause of death compared with mixed drug overdoses and incidental findings. Free oxycodone concentrations in postmortem cases must be interpreted in the context of the deceased's past medical history and autopsy findings.
| 19,007,520
|
Virus-induced vasculitis.
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There is a growing understanding of the different syndromes that have a definite, and in some cases a possible, association with viral infections. Hepatitis C virus-associated mixed cryoglobulinemias and hepatitis B virus-associated polyarteritis nodosa are examples of a vasculitis with a definite viral association. However, various types of cutaneous vasculitis are examples of a vasculitis with only a possible association with a viral infection.
| 19,007,534
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Effectiveness of transcutaneous electrical nerve stimulation for treatment of hyperalgesia and pain.
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Transcutaneous electrical nerve stimulation (TENS) is a nonpharmacologic treatment for pain relief. TENS has been used to treat a variety of painful conditions. This review updates the basic and clinical science regarding the use of TENS that has been published in the past 3 years (ie, 2005-2008). Basic science studies using animal models of inflammation show changes in the peripheral nervous system, as well as in the spinal cord and descending inhibitory pathways, in response to TENS. Translational studies show mechanisms to prevent analgesic tolerance to repeated application of TENS. This review also highlights data from recent randomized, placebo-controlled trials and current systematic reviews. Clinical trials suggest that adequate dosing, particularly intensity, is critical to obtaining pain relief with TENS. Thus, evidence continues to emerge from both basic science and clinical trials supporting the use of TENS for the treatment of a variety of painful conditions while identifying strategies to increase TENS effectiveness.
| 19,007,541
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Influencing population health performance: feedback from managers, population health staff and clinicians on the NSW Population Health Standards for Area Health Services.
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The NSW Population Health Standards for Area Health Services have recently been introduced in NSW to assist area health services assess and improve performance in population health. Greater Western Area Health Service was the pilot site for trialling the Standards as a self-assessment tool. Following self-assessment, managers, population health staff and clinicians were asked for feedback. Staff were either interviewed or participated in a group discussion. Consulting with staff who would be required to use the Standards in the long term was seen as important for facilitating implementation across the area health service. The Standards were seen as credible and potentially beneficial, especially in raising the profile of population health work and encouraging population-based and integrated approaches.
| 19,007,542
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Oestradiol-induced spermatogenesis requires a functional androgen receptor.
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Spermatogenesis requires androgen but, paradoxically, oestradiol (E2) treatment stimulates spermatogenic development in gonadotrophin- and androgen-deficient hypogonadal (hpg) mice. The mechanisms of E2-induced spermatogenesis were investigated by determining intratesticular E2 levels and testis cell populations in E2-treated hpg male mice, and E2 spermatogenic actions were determined in androgen receptor-knockout (ARKO) mice. Despite increased serum E2 concentrations (150-300 pmol L(-1)), intratesticular E2 concentrations declined fivefold (P < 0.001) in E2-treated v. untreated hpg male mice. Serum FSH reached 40% of normal and total testicular numbers of known FSH-responsive Sertoli, spermatogonia and meiotic spermatocyte populations were significantly (P < 0.001) elevated 1.7-, 4- and 13-fold, respectively. However, E2 administration also increased androgen-dependent pachytene spermatocytes and post-meiotic spermatids to levels comparable with testosterone-treated hpg testes. Selective investigation of androgen receptor involvement used E2-treated ARKO mice, which were found to exhibit increased (1.6-fold; P < 0.05) intratesticular E2 concentrations and suppression of the elevated serum gonadotrophins, although FSH remained twofold higher than normal. However, testis size and total Sertoli, spermatogonia and spermatocyte numbers were not increased in E2-treated ARKO male mice. Therefore, E2-stimulated murine spermatogenic development occurs with markedly suppressed and not elevated intratesticular E2 levels and displays an absolute requirement for functional androgen receptors. We propose that this paradoxical E2 spermatogenic response is explained by predominantly extratesticular E2 actions, increasing FSH to combine with residual androgen activity in hpg testes to stimulate pre- to post-meiotic development.
| 19,007,549
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Admission to hospital for effects of heat and light: NSW, 1993-94 to 2003-04.
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The study examined the hospital admission rates and characteristics of patients experiencing severe heat-related morbidity in NSW using data from the NSW Health Inpatient Statistics Collection. The study covered the 11-year period from July 1993 to June 2004. ICD-10-AM. codes examined included T67 (effects of heat and light). There was an average of 91 admissions for each year due to a principal diagnosis of the effects of heat and light, with consistently more males than females admitted (1.7 : 1). Many of the admissions (39%) were of people 65 years of age or older. Most admissions (49%) occurred in the summer months of December and January.
| 19,007,545
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[Necrotic lipoma of the posterior mediastinum].
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Lipomas are well-differentiated, encapsulated masses composed of adipocytes. Intrathoracic lipomas are rare, but found most commonly in the pleura or anterior mediastinum. Computed tomography shows fatty, homogenous content of the mass and will establish the diagnosis. Areas with a higher fat density are suggestive of liposarcoma. We describe a case of lipoma in the posterior mediastinum that contained solid areas on computed tomography. Histology showed that these areas were fat necrosis.
| 19,007,571
|
[Analysis of mortality in myocardial infarction patients treated with primary angioplasty].
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Primary angioplasty is an effective method to achieve myocardial reperfusion in ST-elevated myocardial infarction (MI). The objective of this study was to determine the independent factors that could predict mortality in MI patients treated with primary angioplasty and to analyze the prognostic value of tissue reperfusion parameters in those patients. A prospective observational study was performed in 380 consecutive patients with ST-elevated MI treated with primary angioplasty at a single hospital. Early mortality was 8.9%. Upon univariate analysis, the following variables were associated with significantly higher mortality: age, ejection fraction (EF), multivascular disease, anterior location of MI, lack of resolution of ST segment, flow 0-1 of TIMI, grade 0-1 of blush index and delay time above 4 hours. Multivariate analysis yielded the following independent variables as predictors of mortality: age, degree of heart failure (Killip index) and degree of myocardial perfusion (blush index). The independent predictive factors of mortality in patients with ST-elevated MI and treated with primary angioplasty are: age, degree of heart failure (Killip index) and degree of myocardial reperfusion (blush index). The resolution of ST segment and blush index represent additional prognostic variables in patients with good epicardial reperfusion.
| 19,007,575
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Evaluation of diffuse myocardial fibrosis in heart failure with cardiac magnetic resonance contrast-enhanced T1 mapping.
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The purpose of this study was to investigate a noninvasive method for quantifying diffuse myocardial fibrosis with cardiac magnetic resonance imaging (CMRI). Diffuse myocardial fibrosis is a fundamental process in pathologic remodeling in cardiomyopathy and is postulated to cause increased cardiac stiffness and poor clinical outcomes. Although regional fibrosis is easily imaged with cardiac magnetic resonance, there is currently no noninvasive method for quantifying diffuse myocardial fibrosis. We performed CMRI on 45 subjects (25 patients with heart failure, 20 control patients), on a clinical 1.5-T CMRI scanner. A prototype T(1) mapping sequence was used to calculate the post-contrast myocardial T(1) time as an index of diffuse fibrosis; regional fibrosis was identified by delayed contrast enhancement. Regional and global systolic function was assessed by cine CMRI in standard short- and long-axis planes, with echocardiography used to evaluate diastology. An additional 9 subjects underwent CMRI and endomyocardial biopsy for histologic correlation. Post-contrast myocardial T(1) times correlated histologically with fibrosis (R = -0.7, p = 0.03) and were shorter in heart failure subjects than controls (383 +/- 17 ms vs. 564 +/- 23 ms, p < 0.0001). The T(1) time of heart failure myocardium was shorter than that in controls even when excluding areas of regional fibrosis (429 +/- 22 ms vs. 564 +/- 23 ms, p < 0.0001). The post-contrast myocardial T(1) time shortened as diastolic function worsened (562 +/- 24 ms in normal diastolic function vs. 423 +/- 33 ms in impaired diastolic function vs. 368 +/- 20 ms in restrictive function, p < 0.001). Contrast-enhanced CMRI T(1) mapping identifies changes in myocardial T(1) times in heart failure, which appear to reflect diffuse fibrosis.
| 19,007,595
|
The role of assisted hatching in in vitro fertilization: a review of the literature. A Committee opinion.
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This Committee Opinion reviews the published literature regarding appropriate usage of assisted hatching as a part of in vitro fertilization.
| 19,007,629
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Salpingectomy for hydrosalpinx prior to in vitro fertilization.
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Salpingectomy for hydrosalpinges before in vitro fertilization increases the success rate.
| 19,007,649
|
Androgen deficiency in the aging male.
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The purpose of this Educational Bulletin is to review current methods of evaluation, the indications for treatment, and to provide recommendations for treatment of androgen deficiency in the aging male (ADAM).
| 19,007,654
|
Chapter 4. Using the zebrafish to study vessel formation.
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Danio rerio, commonly referred to as the zebrafish, is a powerful animal model for studying the formation of the vasculature. Zebrafish offer unique opportunities for in vivo analysis of blood and lymphatic vessels formation because of their accessibility to large-scale genetic and experimental analysis as well as the small size, optical clarity, and external development of zebrafish embryos and larvae. A wide variety of established techniques are available to study vessel formation in the zebrafish, from early endothelial cell differentiation to adult vessel patterning. In this chapter, we review methods used to functionally manipulate and visualize the vasculature in the zebrafish and illustrate how these methods have helped further understanding of the genetic components regulating formation and patterning of developing vessels.
| 19,007,661
|
Chapter 12. Structure of microvascular networks in genetic hypertension.
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Microvascular rarefaction, defined by a loss of terminal arterioles, small venules, and/or capillaries, is a common characteristic of the hypertension syndrome. While rarefaction has been associated with vessel-specific free radical production, deficient leukocyte adhesion, and cellular apoptosis, the relationships of rarefaction with structural alterations at the network and cellular level remain largely unexplored. The objective of this study was to examine the architecture and perivascular cell phenotypes along microvascular networks in hypertensive versus normotensive controls in the context of imbalanced angiogenesis. Mesenteric tissues from age-matched adult male spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats were harvested and immunolabeled for PECAM and neuron-glia antigen 2 (NG2). Evaluation of intact rat mesenteric microvascular networks rats suggests that network alterations associated with hypertension are more complex than just a loss of vessels. Typical SHR versus WKY networks demonstrate a reduced branching architecture marked by more proximal arteriole/venous anastomoses and an absence of NG2 labeling along arterioles. Although less frequent, larger SHR microvascular networks display regions of dramatically increased vascular density. SHR and WKY lymphatic networks demonstrate increased vessel diameters and vascular density compared to networks in normotensive Wistar rats (the strain from which both the SHR and WKY originated). These observations provide a rationale for investigating the presence of local angiogenic factors and response of microvascular networks to therapies aimed at reversing rarefaction in genetic hypertension.
| 19,007,669
|
Nonthyroidal illness syndrome and euthyroid sick syndrome in intensive care patients.
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This article reviews the pathophysiology of non-thyroidal illness syndrome (NTIS) and euthyroid sick syndrome (ESS), a multifactorial phenomenon characterized by suppression of thyroid hormone levels that has been described in several disease states, probably due to different causes in different patients. It also describes the laboratory values of thyroid function tests (TFTs), relevant animal studies, the association of NTIS and ESS with cardiovascular problems and sepsis, and the rationale for treatment.
| 19,007,679
|
Thyroid hormone regulation of perinatal cardiovascular function.
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Thyroid hormone plays an important role in regulating cardiovascular function during the transition to extrauterine physiology. Multiple mechanisms participate, ranging from transcriptional to more immediate nongenomic modes of regulation.
| 19,007,680
|
Progression of peripheral arterial disease predicts cardiovascular disease morbidity and mortality.
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The purpose of this study was to examine the association of progressive versus stable peripheral arterial disease (PAD) with the risk of future cardiovascular disease (CVD) events. An independent association between PAD, defined by low values of the ankle-brachial index (ABI), and future CVD risk has been demonstrated. However, the prognostic significance of declining versus stable ABI has not been studied. We recruited 508 subjects (59 women, 449 men) from 2 hospital vascular laboratories in San Diego, California. ABI and CVD risk factors were measured at Visit 2 (1990 to 1994). ABI values from each subject's earliest vascular laboratory examination (Visit 1) were abstracted from medical records. Mortality and morbidity were tracked for 6 years after Visit 2 using vital statistics and hospitalization data. In multivariate models adjusted for CVD risk factors, very low (<0.70) and, in some cases, low (0.70 < or = ABI <0.90) Visit 2 ABIs were associated with significantly elevated all-cause mortality, CVD mortality, and combined CVD morbidity/mortality at 3 and 6 years. Decreases in ABI of more than 0.15 between Visit 1 and Visit 2 were significantly associated with an increased risk of all-cause mortality (risk ratio [RR]: 2.4) and CVD mortality (RR: 2.8) at 3 years, and CVD morbidity/mortality (RR: 1.9) at 6 years, independent of Visit 2 ABI and other risk factors. Progressive PAD (ABI decline >0.15) was significantly and independently associated with increased CVD risk. Patients with decreasing ABI may be candidates for more intensive cardiovascular risk factor management.
| 19,007,695
|
A collaborative curricular model for implementing evidence-based nursing in a critical care setting.
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This article discusses how a curricular model for introducing nurses to the Registered Nurses' Association of Ontario Best Practice Guideline Risk Assessment and Prevention of Pressure Ulcers was used to reduce pressure ulcer prevalence in the critical care setting. This curricular model is particularly relevant to hospitals that are on the Magnet Journey or are involved in other quality improvement efforts to develop an evidence-based nursing practice culture.
| 19,007,708
|
Working in an eICU unit: life in the box.
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This ethnographic study of the VISICU eICU (VSISCU, Inc., Baltimore, MD) work environment in a large midwestern health care system describes everyday life working in a telemedicine intensive care. Data were gathered through 60 hours of observation and formal interviews of eICU clinician team members. Working in the remote telemedicine center, often referred to as the "Box", is like working in an air traffic control center. Remote oversight and effective communication ensure the best possible outcomes to support the bedside intensive care unit team.
| 19,007,710
|
Simulation as a vehicle for enhancing collaborative practice models.
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Clinical simulation used in a collaborative practice approach is a powerful tool to prepare health care providers for shared responsibility for patient care. Clinical simulations are being used increasingly in professional curricula to prepare providers for quality practice. Little is known, however, about how these simulations can be used to foster collaborative practice across disciplines. This article provides an overview of what simulation is, what collaborative practice models are, and how to set up a model using simulations. An example of a collaborative practice model is presented, and nursing implications of using a collaborative practice model in simulations are discussed.
| 19,007,713
|
Specific IgA and IgG antibodies in paired serum and breast milk samples in human strongyloidiasis.
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Strongyloidiasis, caused by the nematode Strongyloides stercoralis, is one of the major worldwide parasitic infections in humans. Breastfeeding may offer a potential protection against this infection. Feces, serum and milk samples were obtained from 90 lactating women from Clinical Hospital of Universidade Federal de Uberlândia, Brazil. The fecal samples were collected for parasitological diagnosis and the serum and milk samples were examined for specific S. stercoralis IgA and IgG antibodies using the indirect fluorescent antibody test (IFAT) and enzyme-linked immunosorbent assay (ELISA). Fecal examination showed that the rate of prevalence of S. stercoralis infection in the lactating women was 4.4%. IFAT manifested a 16.7% positivity rate for specific IgA antibody in serum and a 28.9% rate in milk samples; specific IgG was 41.1% in serum and 25.5% in milk samples. According to ELISA the positivity rate for specific IgA antibody was 21.1% in serum and 42.2% in milk samples; specific IgG was 40% in serum and 18.9% in milk samples. In serum samples, these immunological tests showed a concurrence of 91.1% and 94.4%, respectively, in detecting specific IgA and IgG antibodies. In milk samples, they showed a concurrence of 70% and 78.9%, respectively, in detecting specific IgA and IgG antibodies. There was a statistically significant difference between concordant and discordant results of immunological tests (P<0.0001). IFAT and ELISA highly concurred in their detection of specific S. stercoralis IgA and IgG antibodies in serum and in milk samples reconfirming prior studies that the serological method is a complement to the direct diagnosis of the parasite, and suggesting that immunological methods using milk samples can also be helpful. Furthermore, in endemic areas, infants may acquire antibodies to S. stercoralis from breast milk, possibly, contributing to the enhancement of specific mucosal immunity against this parasite.
| 19,007,741
|
Activation of hindbrain neurons in response to gastrointestinal lipid is attenuated by high fat, high energy diets in mice prone to diet-induced obesity.
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Food intake is controlled by peripheral signals from the gastrointestinal tract and adipocytes, which are integrated within the central nervous system. There is evidence that signals from the GI tract are modulated by long term changes in diet, possibly leading to hyperphagia and increased body weight. We tested the hypothesis that diet-induced obese-prone (DIO-P) and obese-resistant (DIO-R) mice strains differ in the long term adaptive response of the gut-brain pathway to a high fat diet. Immunochemical detection of Fos protein was used as a measure of neuronal activation in the nucleus of the solitary tract (NTS) in response to intragastric administration of lipid in DIO-P (C57Bl6) and DIO-R (129sv) mouse strains maintained on chow or high fat, high energy diets (45% or 60% kcal from fat). Intragastric lipid administration activated neurons in the NTS in both DIO-P and DIO-R mice; the number of activated neurons was significantly greater in DIO-P than in DIO-R mice (P<0.001). However, lipid-induced activation of NTS neurons in DIO-P mice was attenuated by approximately 30% after maintenance on either 45% or 60% HF diet, for 4 or 8 weeks, compared to chow fed controls (P<0.05). In contrast, in DIO-R mice, maintenance on a HF diet (45% or 60%) had no effect on lipid-induced activation of NTS neurons. These results demonstrate that DIO-P and DIO-R mice strains differ in the adaptation of the pathway to long term ingestion of high fat diets, which may contribute to decrease satiation and increased food intake.
| 19,007,755
|
Rac1 deficiency in the forebrain results in neural progenitor reduction and microcephaly.
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The Rho family of small GTPases has been implicated in many neurological disorders including mental retardation, but whether they are involved in primary microcephaly (microcephalia vera) is unknown. Here, we examine the role of Rac1 in mammalian neural progenitors and forebrain development by a conditional gene-targeting strategy using the Foxg1-Cre line to delete floxed-Rac1 alleles in the telencephalic ventricular zone (VZ) of mouse embryos. We found that Rac1 deletion in the telencephalic VZ progenitors resulted in reduced sizes of both the striatum and cerebral cortex. Analyses further indicated that this abnormality was caused by accelerated cell-cycle exit and increased apoptosis during early corticogenesis (approximately E14.5), leading to a decrease of the neural progenitor pool in mid-to-late telencephalic development (E16.5 to E18.5). Moreover, the formation of patch-matrix compartments in the striatum was impaired by Rac1-deficiency. Together, these results suggest that Rac1 regulates self-renewal, survival, and differentiation of telencephalic neural progenitors, and that dysfunctions of Rac1 may lead to primary microcephaly.
| 19,007,770
|
Influence of terminal nerve branch size on motor neuron regeneration accuracy.
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A necessary prerequisite for recovery of motor function following a peripheral nerve injury is the correct choice by regenerating motor neurons to reinnervate the original distal nerve branch to denervated muscle. The present studies use the mouse femoral nerve as a model system to examine factors that influence such motor neuron regeneration accuracy. We examined motor reinnervation accuracy over time in this model under two conditions: 1) when the two terminal nerve branches to either skin (cutaneous) or muscle (quadriceps) were roughly comparable in size, and 2) when the cutaneous branch was larger than the muscle branch. When the terminal nerve branches were similar in size, motor neurons initially projected equally into both branches, but over time favored the terminal muscle branch. When the cutaneous terminal nerve branch was enlarged (via transgenic technology), motor neuron projections significantly favored this inappropriate pathway during early time points of regeneration. These results suggest that regenerating motor neuron projections are not determined by inherent molecular differences between distal terminal nerve branches themselves. Rather, we propose a two-step process that shapes motor neuron reinnervation accuracy. Initial outgrowth choices made by motor axons at the transection site are proportional to the relative amount of target nerve associated with distal nerve axons that previously projected to each of the terminal nerve pathways. Secondly, the likelihood of an axon collateral from a motor neuron remaining in either terminal nerve branch is based upon the relative trophic support provided to the parent motor neuron by the competing terminal pathways and/or end-organs.
| 19,007,776
|
Perfusion fixation preserves enhanced yellow fluorescent protein and other cellular markers in lymphoid tissues.
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Fluorescent proteins are increasingly being used to analyze cellular gene expression and to facilitate tracking of cell lineages in vivo. One of these, enhanced yellow fluorescent protein (EYFP) has several properties such as intense fluorescence and little to no toxicity in cells, which makes it an excellent molecule to label proteins and cells of interest. In live cells, visualization of EYFP has been highly successful; however, detection of EYFP in lymphoid tissue sections, particularly in combination with other markers of interest has been difficult. This is because of the enhanced solubility of EYFP in the absence of fixation. When extended fixation protocols are employed, EYFP is preserved but detection of other cellular antigens becomes problematic due to over fixation. Here we demonstrate that EYFP-expressing T and B cells can be efficiently visualized in lymphoid tissue sections without compromising the ability to detect other cellular markers.
| 19,007,785
|
Nrf2 is critical in defense against high glucose-induced oxidative damage in cardiomyocytes.
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Exposure to high levels of glucose induces the production of reactive oxygen species (ROS) in cardiomyocytes that may contribute to the development of cardiomyopathy in diabetes. Nuclear factor erythroid 2-related factor 2 (Nrf2) controls the antioxidant response element (ARE)-dependent gene regulation in response to oxidative stress. The role of Nrf2 in defense against high glucose-induced oxidative damage in cardiomyocytes was investigated. Glucose at high concentrations induced ROS production in both primary neonatal and adult cardiomyocytes from the Nrf2 wild type (WT) mouse heart, whereas, in Nrf2 knockout (KO) cells, ROS was significantly higher under basal conditions and high glucose markedly further increased ROS production in concentration and time-dependent manners. Concomitantly, high glucose induced significantly higher levels of apoptosis at lower concentrations and in shorter time in Nrf2 KO cells than in WT cells. Primary adult cardiomyocytes from control and diabetic mice also showed dependence on Nrf2 function for isoproterenol-stimulated contraction. Additionally, cardiomyocytes from Nrf2 KO mice exhibited increased sensitivity to 3-nitropropionic acid, an inhibitor of mitochondrial respiratory complex II, for both ROS production and apoptosis compared with Nrf2 WT cells, further emphasizing the role of Nrf2 in ROS defense in the cells. Mechanistically, Nrf2 was shown to mediate the basal expression and induction of ARE-controlled cytoprotective genes, Nqo1 and Ho1, at both mRNA and protein levels in cardiomyocytes, as both the basal and inducible expressions of the genes were lost in Nrf2 KO cells or largely reduced by Nrf2 SiRNA. The findings, for the first time, established Nrf2 as a critical regulator of defense against ROS in normal and diabetic hearts.
| 19,007,787
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Complex patterns of histidine, hydroxylated amino acids and the GxxxG motif mediate high-affinity transmembrane domain interactions.
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Specific interactions of transmembrane helices play a pivotal role in the folding and oligomerization of integral membrane proteins. The helix-helix interfaces frequently depend on specific amino acid patterns. In this study, a heptad repeat pattern was randomized with all naturally occurring amino acids to uncover novel sequence motifs promoting transmembrane domain interactions. Self-interacting transmembrane domains were selected from the resulting combinatorial library by means of the ToxR/POSSYCCAT system. A comparison of the amino acid composition of high-and low-affinity sequences revealed that high-affinity transmembrane domains exhibit position-specific enrichment of histidine. Further, sequences containing His preferentially display Gly, Ser, and/or Thr residues at flanking positions and frequently contain a C-terminal GxxxG motif. Mutational analysis of selected sequences confirmed the importance of these residues in homotypic interaction. Probing heterotypic interaction indicated that His interacts in trans with hydroxylated residues. Reconstruction of minimal interaction motifs within the context of an oligo-Leu sequence confirmed that His is part of a hydrogen bonded cluster that is brought into register by the GxxxG motif. Notably, a similar motif contributes to self-interaction of the BNIP3 transmembrane domain.
| 19,007,788
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Ribosomal intersubunit bridge B2a is involved in factor-dependent translation initiation and translational processivity.
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Intersubunit bridges are important for holding together subunits in the 70S ribosome. Moreover, a number of intersubunit bridges have a role in modulating the activity of the ribosome during translation. Ribosomal intersubunit bridge B2a is formed by the interaction between the conserved 23S rRNA helix-loop 69 (H69) and the top of the 16S rRNA helix 44. Within the 70S ribosome, bridge B2a contacts translation factors and the A-site tRNA. In addition to bridging the subunits, bridge B2a has been invoked in a number of other ribosomal functions from initiation to termination. In the present work, single-nucleotide substitutions were inserted at positions 1912 and 1919 of Escherichia coli 23S rRNA (helix 69), which are involved in important intrahelical and intersubunit tertiary interactions in bridge B2a. The resulting ribosomes had a severely reduced activity in a cell-free translation elongation assay, but displayed a nearly wild-type-level peptidyl transferase activity. In vitro reassociation efficiency decreased with all of the H69 variant 50S subunits, but was severest with the A1919C and DeltaH69 variants. The mutations strongly affected initiation-factor-dependent 70S initiation complex formation, but exhibited a minor effect on the nonenzymatic initiation process. The mutations decreased ribosomal processivity in vitro and caused a progressive depletion of 50S subunits in polysomal fractions in vivo. Mutations at position 1919 decreased the stability of a dipeptidyl-tRNA in the A-site, whereas the binding of the dipeptidyl-tRNA was rendered more stable with 1912 and DeltaH69 mutations. Our results suggest that the H69 of 23S rRNA functions as a control element during enzymatic steps of translation.
| 19,007,789
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Differential antimicrobial peptide gene expression patterns during early chicken embryological development.
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The adaptive immune system is not completely developed when chickens hatch, so the innate immune system has evolved a range of mechanisms to deal with early pathogenic assault. Avian beta-defensins (AvBDs) and cathelicidins (CTHLs) are two major sub-classes of antimicrobial peptides (AMPs) with a fundamental role in both innate and adaptive immune responses. In this study, we demonstrate distinct expression patterns of innate immune genes including - Toll-like receptors (TLRs) (TLR2, TLR15 and TLR21, but not TLR4), the complete repertoire of AvBDs, CTHLs and both pro- and anti-inflammatory cytokines (IL1B, IL8, IFNG and IL10) during early chicken embryonic development. AvBD9 was significantly increased by over 150 fold at day 9; and AvBD10 was increased by over 100 fold at day 12 in the abdomen of the embryo, relative to day 3 expression levels (P<0.01). In contrast, AvBD14 was preferentially expressed in the head of the embryo. This is the first study to demonstrate differential patterns of AMP gene expression in the sterile environment of the developing embryo. Our results propose novel roles for AMPs during development and reveal the innate preparedness of developing embryos for pathogenic assault in ovo, or post-hatching.
| 19,007,808
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Time-dependent segmentation of BrdU-signal leads to late detection problems in studies using BrdU as cell label or proliferation marker.
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Bromodeoxyuridine incorporates into DNA during mitosis. A long-term stability of the incorporated BrdU is important for the recovery of BrdU-labeled cells. For testing the stability of BrdU incorporation into DNA we pulse-labeled mesenchymal stem cells with BrdU and observed these cells in vitro over 4 weeks. During this time the BrdU-signal was permanently decreasing. Starting with cells containing evenly stained BrdU-nuclei, so-called filled cells, already 3 days after BrdU removal we detected cells containing so-called segmented and punctated BrdU-signals. The number of those labeled cells continuously increased over time. Interestingly, the loss of BrdU in the nucleus was accompanied by an increasing labeling of the cytosol. Further, we injected BrdU intraperitoneally into rats after ischemia and detected BrdU-positive cells in the hippocampus 3 and 23 days after the last BrdU injection. While after 3 days most of the BrdU-positive cells in the hippocampus displayed a filled BrdU-signal, 23 days after BrdU removal an increased number of segmented and punctated BrdU-positive nuclei was detected. The gradual degradation of the BrdU-signal was not caused by cell death. The consequence of this BrdU degradation would be an underestimation of cell proliferation and an overestimation of cell death of newly generated cells.
| 19,007,815
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Chimeric virus-like particles for the delivery of an inserted conserved influenza A-specific CTL epitope.
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The small hepatitis B virus surface antigens (HBsAg-S) have the ability to self-assemble with host-derived lipids into empty non-infectious virus-like particles (VLPs). HBsAg-S VLPs are the sole component of the licensed hepatitis B vaccine, and they are a useful delivery platform for foreign epitopes. To develop VLPs capable of transporting foreign cytotoxic T lymphocyte (CTL) epitopes, HBsAg-S specific CTL epitopes at various sites were substituted with a conserved CTL epitope derived from the influenza matrix protein. Depending on the insertion site, the introduction of the MHC class I A2.1-restricted influenza epitope was compatible with the secretion competence of HBsAg-S indicating that chimeric VLPs were assembled. Immunizations of transgenic HHDII mice with chimeric VLPs induced anti-influenza CTL responses proving that the inserted foreign epitope can be correctly processed and cross-presented. Chimeric VLPs in the absence of adjuvant were able to induce memory T cell responses, which could be recalled by influenza virus infections in the mouse model system. The ability of chimeric HBsAg-S VLPs to induce anti-foreign CTL responses and also with the proven ability to induce humoral immune responses constitute a highly versatile platform for the delivery of selected multiple epitopes to target disease associated infectious agents.
| 19,007,818
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Identification of nose-to-brain homing peptide through phage display.
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Brain delivery of drug molecules through the nasal passage represents a viable approach for bypassing the blood-brain barrier (BBB) but remains a major challenge due to lack of efficient homing carriers. To screen for potential peptides with the ability to transport into the brain via the nasal passage, we applied a C7C phage peptide display library (Ph.D.-C7C) intra-nasally to anesthetized rats and recovered phage from the brain tissue 45 min after phage administration. After three rounds of panning, 10 positive phage clones were selected and sequenced. Clone7, which exhibited highest translocation efficiency, was chosen for further studies. After nasal administration, Clone7 entered the brain within 30 min and exhibited translocation efficiency about 50-fold higher than a random phage. A 11-amino acid synthetic peptide derived from the displayed sequence of Clone7 (ACTTPHAWLCG) efficiently inhibited the nasal-brain translocation of Clone7. Both phage recovery results and fluorescent microscopy images revealed the presence of many more Clone7 phage in the brain than in the liver, kidney and other internal organs after the nasal administration, suggesting that Clone7 bypassed the BBB and entered brain directly. Furthermore, both Clone7 and the ACTTPHAWLCG peptide were found to be heavily distributed along the olfactory nerve after the nasal administration, further suggesting a direct passage route into the brain via the olfactory region. These results demonstrated the feasibility of using the in vivo phage display approach for selecting peptides with the nose-to-brain homing capability and may have implications for the development of novel targeting carriers useful for brain delivery.
| 19,007,831
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Immunogenicity and safety of measles-mumps-rubella-varicella (MMRV) vaccine followed by one dose of varicella vaccine in children aged 15 months-2 years or 2-6 years primed with measles-mumps-rubella (MMR) vaccine.
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In this open, randomized, comparative study (105908/NCT00353288), 458 age-stratified children (15 months-2 years and 2-6 years) previously primed with MMR received one dose of either a combined MMRV vaccine (Priorix-Tetra, MMRV group) or concomitant MMR and varicella vaccines (Priorix and Varilrix, MMR+V group), followed 42-56 days later by another dose of varicella vaccine (Varilrix) in both groups. Post-vaccination measles, mumps and rubella seropositivity rates and antibody geometric mean titers (GMTs) were high (99.5% for anti-measles and 100% for anti-mumps and anti-rubella) in both vaccine groups. In the two age strata, varicella seroconversion rates were, post-dose 1: > or =97.6% (MMRV), > or =96.6% (MMR+V) and, post-dose 2: 100% in both groups. Post-dose 2, anti-varicella GMTs increased respectively 14.1- and 12.6-fold (MMRV), and 9.8- and 13.1-fold (MMR+V). Both vaccine regimens were well-tolerated. Post-dose 1, the incidence of any solicited local symptom during the 4-days follow-up was < or =28.2% (MMRV) and < or =19.8% (MMR+V) and the incidence of fever >39.5 degrees C (rectal temperature) within 15 days was < or =2.8% (MMRV) and < or =2.6% (MMR+V). This MMRV vaccine appears an immunogenic and safe substitute for a second dose of MMR vaccine in young children. The increase in anti-varicella antibodies observed after a second dose of varicella vaccine supports a two-dose schedule for varicella-containing vaccine.
| 19,007,835
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Insights into the role of genetic alterations in adrenocortical tumorigenesis.
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Whereas benign adrenocortical tumors are frequent in the population, adrenocortical carcinoma (ACC) is a rare cancer. Significant advances in the understanding of the pathogenesis of sporadic ACCs have been possible through the study of hereditary syndromes responsible for ACCs. The genetic alterations involved in these syndromes have also been found in sporadic ACCs. Several specific genes have been shown to be altered in sporadic ACCs. Despite these progresses, the underlying sequence(s) of events remains to be elucidated. Progressive transformation of a normal tissue into a benign tumor and ultimately into a carcinoma occurs via accumulation of genetic and epigenetic alterations. Likewise, a multistage model has been proposed for the adrenal tumor development. This review summarizes the molecular alterations likely involved in the multistage tumorigenesis and describes a mouse model which allows us to evaluate the effect of individual genes or combination of genes in the development of adrenocortical tumors.
| 19,007,854
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Characterization and monitoring of pseudo-polymorphs in manufacturing process by NIR.
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Moisture-sensitive pseudo-polymorphs with different stabilities were characterized, and their polymorphisms were monitored in the process of tableting and film coating by near-infrared (NIR) spectroscopy. In this study, we proved that we could successfully maintain the crystal form ratio in the tablet by controlling the moisture profile during the manufacture to sufficiently stabilize the drug product. Mitemcinal fumarate is an erythromycin derivative with two pseudo-polymorphic forms, hydrate and anhydrate. We characterized them by X-ray powder diffraction and water sorption isotherm plot analysis. Stability test revealed that the hydrate form is more stable than the anhydrate form. We established a quantitative method by using NIR and monitored the hydrate form ratio in the tablet during the tableting and coating process. The manufacturing room was controlled to between 40 and 60% RH. Although the hydrate form ratio just after the onset of tableting decreased to below 40%, 60% was obtained at the end of the final process which sufficiently retains stability. Transition of the hydrate form ratio during the manufacturing process was reasonable; this indicates that our NIR method is suitable for monitoring. Thus, NIR is one of the most suitable tools for in-process testing of these humidity-sensitive APIs.
| 19,007,870
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Self-assembled drug delivery systems: Part 3. In vitro/in vivo studies of the self-assembled nanoparticulates of cholesteryl acyl didanosine.
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Self-assembled drug delivery systems (SADDS) are defined as the self-assemblies of amphiphilic prodrugs, integrating prodrugs, molecular self-assembly and nanotechnology for drug targeting and controlled release. Cholesteryl-succinyl didanosine (CSD) and cholesteryl-adipoyl didanosine (CAD) nanoparticulate systems in water were previously prepared and optimized. In this paper, the in vitro and in vivo behavior of them was investigated. Precipitation occurred when they were mixed with acid solutions due to rapid production of hypoxanthine and subsequent disruption of supramolecular structures. They showed pH-dependent degradation and kept relatively stable in the neutral pH range. CSD is more stable than CAD due to the shorter spacer and poloxamer protection. CSD showed different degradation rates in various plasma with the descending order of rat, mouse, rabbit, dog and human. The half-life (t(1/2)) of CSD is 9 days in rat plasma, and 5.9 days in rat liver homogenates. CAD has a faster degradation than CSD though the t(1/2) in rat liver homogenates is long to 23 h. CSD nanoparticulates showed no significant anti-HIV effect in MT4 cell model because of very slow degradation. CSD nanoparticulates showed the distribution t(1/2) of 7.6 min after bolus intravenous (i.v.) administration to rats, and the site-specific distribution in liver, lung and spleen with the high t(1/2) of 10 days in liver. The factors affecting achievement of successful SADDS are discussed.
| 19,007,871
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Glycogen synthase kinase-3 regulates microglial migration, inflammation, and inflammation-induced neurotoxicity.
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Microglia play a prominent role in the brain's inflammatory response to injury or infection by migrating to affected locations, secreting inflammatory molecules, and phagocytosing damaged tissue. However, because severe or chronic neuroinflammation exacerbates many neurological conditions, controlling microglia actions may provide therapeutic benefits in a diverse array of diseases. Since glycogen synthase kinase-3 (GSK3) promotes inflammatory responses in peripheral immune cells, we investigated if inhibitors of GSK3 attenuated microglia responses to inflammatory stimuli. Treatment of BV-2 microglia with GSK3 inhibitors greatly reduced the migration of microglia in both a scratch assay and in a transwell migration assay. Treatment of BV-2 microglia with lipopolysaccharide (LPS) stimulated the production of interleukin-6 and increased the expression of inducible nitric oxide synthase (iNOS) and NO production. Each of these microglia responses to inflammatory stimulation were greatly attenuated by GSK3 inhibitors. However, GSK3 inhibitors did not cause a general impairment of microglia functions, as the LPS-induced stimulated expression of cyclooxygenase-2 was unaltered. Regulation of microglia functions were also evident in cultured mouse hippocampal slices where GSK3 inhibitors reduced cytokine production and microglial migration, and provided protection from inflammation-induced neuronal toxicity. These findings demonstrate that GSK3 promotes microglial responses to inflammation and that the utilization of GSK3 inhibitors provides a means to limit the inflammatory actions of microglia.
| 19,007,880
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The C1 and C2 domains target human type 6 adenylyl cyclase to lipid rafts and caveolae.
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Previous data has shown that adenylyl cyclase type 6 (AC6) is expressed principally in lipid rafts or caveolae of cardiac myocytes and other cell types while certain other isoforms of AC are excluded from these microdomains. The mechanism by which AC6 is localized to lipid rafts or caveolae is unknown. In this study, we show AC6 is localized in lipid rafts of COS-7 cells (expressing caveolin-1) and in HEK-293 cells or cardiac fibroblasts isolated from caveolin-1 knock-out mice (both of which lack prototypical caveolins). To determine the region of AC6 that confers raft localization, we independently expressed each of the major intracellular domains, the N-terminus, C1 and C2 domains, and examined their localization with various approaches. The N-terminus did not associate with lipid rafts or caveolae of either COS-7 or HEK-293 cells nor did it immunoprecipitate with caveolin-1 when expressed in COS-7 cells. By contrast, the C1 and C2 domains each associated with lipid rafts to varying degrees and were present in caveolin-1 immunoprecipitates. There were no differences in the pattern of localization of either the C1 or C2 domains between COS-7 and HEK-293 cells. Further dissection of the C1 domain into four individual proteins indicated that the N-terminal half of this domain is responsible for its raft localization. To probe for a role of a putative palmitoylation motif in the C-terminal portion of the C2 domain, we expressed various truncated forms of AC6 lacking most or all of the C-terminal 41 amino acids. These truncated AC6 proteins were not altered in terms of their localization in lipid rafts or their catalytic activity, implying that this C-terminal region is not required for lipid raft targeting of AC6. We conclude that while the C1 domain may be most important, both the C1 and C2 domains of AC6 play a role in targeting AC6 to lipid rafts.
| 19,007,881
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Sensory gating and source analysis of the auditory P50 in low and high suppressors.
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Impairments in sensory gating in schizophrenia have been reflected by diminished suppression of the scalp-recorded middle latency auditory P50 event-related potential (MLAERP) elicited by the second (S(2)) of a pair (S(1)-S(2)) of clicks. As understanding the functional neural substrates of aberrant gating would have important implications for schizophrenia, this study examined the location and time-course of the neural generators of the P50 MLAERP and its gating on subgroups of healthy volunteers exhibiting low (n=12) and high (n=12) P50 suppression. Suppressor differences were observed with S(1) P50 (high>low) and S(2) P50 (high<low) amplitudes, and current source density analysis with standardized Low Resolution Electromagnetic Tomography (sLORETA) evidenced an S(1) P50-related activation of limbic, temporal and parietal regions in the high but not the low suppressors. Distributed source localization of the Gating Difference Wave (GDW), obtained by subtracting the S(2) P50 response from the S(1) P50 response, also revealed a later and sustained frontal activation to characterize high suppressors. These findings suggest that impaired gating of the kind evident in schizophrenia may involve the deficient functioning of multiple interconnected and temporally overlapping activated brain regions.
| 19,007,892
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Preliminary analysis of miRNA pathway in Schistosoma mansoni.
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RNA silencing refers to a series of nuclear and cytoplasmatic processes involved in the post-transcriptional regulation of gene expression or post-transcriptional gene silencing (PTGS), either by sequence-specific mRNA degradation or by translational arrest. The best characterized small RNAs are microRNAs (miRNAs), which predominantly perform gene silencing through post-transcriptional mechanisms. In this work we used bioinformatic approaches to identify the parasitic trematode Schistosoma mansoni sequences that are similar to enzymes involved in the post-transcriptional gene silencing mediated by miRNA pathway. We used amino acid sequences of well-known proteins involved in the miRNA pathway against S. mansoni genome and transcriptome databases identifying a total of 13 putative proteins in the parasite. In addition, the transcript levels of SmDicer1 and SmAgo2/3/4 were identified by qRT-PCR using cercariae, adult worms, eggs and in vitro cultivated schistosomula. Our results showed that the SmDicer1 and SmAgo2/3/4 are differentially expressed during schistosomula development, suggesting that the miRNA pathway is regulated at the transcript level and therefore may control gene expression during the life cycle of S. mansoni.
| 19,007,911
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Towards a cognitive model of distraction by auditory novelty: the role of involuntary attention capture and semantic processing.
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Unexpected auditory stimuli are potent distractors, able to break through selective attention and disrupt performance in an unrelated visual task. This study examined the processing fate of novel sounds by examining the extent to which their semantic content is analyzed and whether the outcome of this processing can impact on subsequent behavior. This issue was investigated across five laboratory experiments in which participants categorized visual left and right arrows while instructed to ignore irrelevant sounds. The results showed that auditory novels that were incongruent with the visual target (e.g., word "left" presented before a right arrow) disrupted performance over and above congruent novels (semantic effect) while both types of novels delayed responses in the visual task compared to a standard sound (novelty effect). No semantic effect was observed for congruent and incongruent standards, suggesting that novelty detection is necessary for involuntary semantic processing to unravel. While the novelty effect augmented as the difference between novels and the standard increased, the semantic effect was immune to this variation. Furthermore, the novelty effect decreased across the task while the semantic effect did not. A general cognitive framework is proposed encompassing these new findings and previous work in an attempt to account for the behavioral impact of irrelevant auditory novels on primary task performance.
| 19,007,926
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Anterior cruciate ligament injury induced by internal tibial torsion or tibiofemoral compression.
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The knee is one of the most frequently injured joints in the human body. Approximately 91% of ACL injuries occur during sporting activities, usually from a non-contact event. The most common kinetic scenarios related with ACL injuries are internal twisting of the tibia relative to the femur or combined torque and compression during a hard landing. The hypothesis of this study was that the magnitudes and types of motion observed after ACL rupture would significantly change from the relative joint displacements present just before ACL injury. Compression or torsion experiments were conducted on 7 pairs of knee joints with repetitive tests at increasing intensity until catastrophic failure. ACL injury was documented in all cases at 5.4+/-2kN of TF compression or 33+/-13Nm of internal tibial torque. The femur displaced posteriorly relative to the tibia in pre-failure and with a higher magnitude in failure tests under both loading conditions. In compression experiments there was internal rotation of the tibia in pre-failure tests, but external rotation of the tibia after the ACL failed. In torsion experiments, failure occurred at 58+/-19 degrees of internal tibial rotation, and valgus rotation of the femur increased significantly after ACL injury. These new data show that the joint motions can vary in magnitude and direction before and after failure of the ACL. Video-based studies consistently document external rotation of the tibia combined with valgus knee bending as the mechanism of ACL injury although these motions could be occurring after ACL rupture.
| 19,007,932
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Large-scale cold water dispersant effectiveness experiments with Alaskan crude oils and Corexit 9500 and 9527 dispersants.
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There continues to be reluctance in some jurisdictions to use chemical dispersants as a viable countermeasure for accidental oil spills. One argument used by some opponents to dispersant use is that "chemical dispersants do not work effectively in cold water". To address this issue, the U.S. Minerals Management Service (MMS) funded and conducted two series of large-scale dispersant experiments in very cold water at Ohmsett - The National Oil Spill Response Test Facility, located in Leonardo, New Jersey in February-March 2006 and January-March 2007. Alaska North Slope, Endicott, Northstar and Pt. McIntyre crude oils and Corexit 9500 and Corexit 9527 dispersants were used in the two test series. The crude oils were tested both when fresh and after weathering. Results demonstrated that both Corexit 9500 and Corexit 9527 dispersants were 85-99% effective in dispersing the fresh and weathered crude oils tested at cold temperatures. The MMS expects that results from these test series will assist government regulators and responders in making science based decisions on the use of dispersants as a response tool for oil spills in the Arctic.
| 19,007,943
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Proteomic identification of differentially-expressed proteins in squamous cervical cancer.
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To identify candidate biomarkers for squamous cervical cancer as well as reveal the molecular mechanism underlying this disease by a proteomic approach. Proteins from 10 pairs of human squamous cervical cancer and matching adjacent normal cervical tissues were separated by two-dimensional gel electrophoresis and the differentially expressed proteins were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Then, some of the interesting proteins obtained were confirmed by Western blotting in the other 20 pairs of tissues. A comparison of protein patterns revealed 55 protein spots significantly changed, of which 24 protein spots with concordantly increased and 31 protein spots with concordantly decreased intensity in squamous cervical cancer compared with adjacent normal cervical tissues. Thirty-two of these proteins were identified by mass spectrometry. The overexpression of the Tyk2, S100A9, and Zinc finger protein 217 in squamous cervical cancer was confirmed by immunoblotting. Our study suggested that a proteomics-based approach is useful for developing a more complete picture of the protein profile of squamous cervical cancer. Further ongoing analysis of these differential proteins will determine their potential applicability to squamous cervical cancer-specific diagnosis and therapeutics.
| 19,007,971
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Identification of O-glycosylated decapeptides within the MUC1 repeat domain as potential MHC class I (A2) binding epitopes.
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The MUC1 glycoprotein is considered a tumor antigen due to its over expression and aberrant glycosylation in cancer tissues. The latter results in appearance of new antigenic tumor specific glycopeptides not found on normal glycoforms of the mucin. MUC1 glycopeptides can be presented by APCs on MHC class II molecules to activate glycopeptide specific helper T-cells. No study has yet reported presentation of MUC1 glycopeptides on MHC class I molecules as stimulators of cytotoxic T-cells. In this study we show that human immunoproteasomes and cathepsin-L can generate octa to undecameric glycopeptides from the MUC1 repeat domain in vitro. We identified glycosylated fragments of which the decameric glycopeptide SAP10 [SAPDT(GalNAc)RPAPG] containing a single sugar binds with comparable strength to the MHC class I allele HLA A*0201 as predicted high-score binding epitopes of the tandem repeat. The same sequence glycosylated with the disaccharide Gal-GalNAc does not bind. The glycan on SAP10 is predicted by molecular modeling to either protrude out or point into the MHC groove. SAPDTRPAPG peptide and the respective glycopeptide stimulated cytotoxic T-cells in vitro. Our findings suggest that MUC1 tandem repeat glycopeptides are capable of activating both helper and cytotoxic T-cells and thus represent good candidates for further development as vaccines.
| 19,007,994
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Paracrine effects of CD34 progenitor cells on angiogenic endothelial sprouting.
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Progenitor cells contribute to repair of ischemia-associated disturbances of microcirculations, but detailed mechanisms of paracrine angiogenic activation of endothelium by progenitor cells are unclear. The present study was designed to test whether progenitor cells maintain their activation pattern of cytokine secretion and capillary-like endothelial sprout attraction under conditions of hypoxia induced angiogenic activation. CD34 progenitor cells were kept separated together with spheroids of human umbilical vein endothelial cells (HUVEC) sharing a common medium supernatant to generate a paracrine diffusion gradient from CD34 cells to the endothelial cell spheroids. The expression of 27 cytokines was analyzed in the supernatant. The length and the direction of the capillary like sprouts were analyzed under 20% and 1% oxygen concentration. Co-culture with CD34 cells increased sprout length of HUVEC spheroids by 18%, while reduction of oxygen concentration from 20% to 1% increased sprout length by 52%. Analysis of the direction of the sprout growth revealed a directed growth toward CD34 cells under normoxic as well as under hypoxic conditions. Paracrine induction of cytokine secretion by co-culture was similar in normoxia and in hypoxia with IL-8 (60-80-fold induction) >IL-6 and MIP-1beta (10-20-fold) >MIP-1alpha and MCP-1 (3-10-fold). These data indicate that CD34 cell induced paracrine activation of cytokine secretion pattern and attraction of endothelial sprouting are well maintained under conditions of hypoxia induced endothelial cell sprout growth. This is a prerequisite for paracrine effectiveness of trapped progenitor cells in hypoperfused and hypooxygenated tissue areas.
| 19,008,002
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The uneven geographies of transnational advocacy: the case of the Talo Dam.
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The Talo Dam was built in 2006 on the Bani River, a tributary of the Niger River in Mali. The path towards the completion of the project has been complex and controversial. This paper offers a case-study of the advocacy efforts initially opposed to, and later in support of the building of the Talo Dam. Several international institutions have been key decision-makers regarding the building of the Talo Dam, but the geographical and culture distance of the decision-making institutions to on-the-ground reality presents a serious obstacle to goals of participatory development and illustrates some inherent challenges of transnational environmental advocacy and management. Several typologies of transnational campaigns are analyzed to demonstrate the range of participation and accountability that a transnational campaign can pursue. Finally, I encourage the use of qualitative research methods by advocacy organizations as a useful methodological approach to counter otherwise inherent challenges to local inclusion and participation.
| 19,008,033
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CXCR4 mediates the proliferation of glioblastoma progenitor cells.
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Increasing evidence points to a fundamental role for cancer stem cells (CSC) in the initiation and propagation of many tumors. As such, in the context of glioblastoma multiforme (GBM), the development of treatment strategies specifically targeted towards CSC-like populations may hold significant therapeutic promise. To this end, we now report that the cell surface chemokine receptor, CXCR4, a known mediator of cancer cell proliferation and invasion, is overexpressed in primary glioblastoma progenitor cells versus corresponding differentiated tumor cells. Furthermore, administration of CXCL12, the only known ligand for CXCR4, stimulates a specific and significant proliferative response in progenitors but not differentiated tumor cells. Taken together, these results implicate an important role for the CXCR4 signaling mechanism in glioma CSC biology and point to the therapeutic potential of targeting this pathway in patients with GBM.
| 19,008,040
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Perceived peer delinquency and the genetic predisposition for substance dependence vulnerability.
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Like many behavioral phenotypes, generalized vulnerability to substance dependence in adolescence has a complex etiology; it is influenced by both genetic and environmental risks, with a heritability of approximately 0.40 [Button, T.M., Hewitt, J.K., Rhee, S.H., Young, S.E., Corley, R.P., Stallings, M.C., 2006. Examination of the causes of covariation between conduct disorder symptoms and vulnerability to drug dependence. Twin Res. Hum. Genet. 9, 38-45]. However, the extent to which the magnitudes of genetic and environmental risk for substance dependence are contextually moderated is unclear. The aim of the current study was to determine whether the etiology of substance dependence vulnerability (DV; total lifetime symptom count of dependence criteria endorsed across numerous substances divided by the number of substances used) varies depending on the extent of affiliation with delinquent peers as perceived by the adolescent. Results show that affiliation with delinquent peers moderates both the unstandardized (absolute) and the relative contribution of genetic, shared, and non-shared environmental risks to the variance of DV. The genetic variance was estimated to be higher among subjects who perceived their peers to be least delinquent and among those who considered their peers to be the most delinquent. The magnitudes of both shared and non-shared environmental influences were negligible among those who perceived their peers to be least delinquent and were greater among those with higher levels of perceived peers' delinquency.
| 19,008,053
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Correlation between CT patterns and pathological classification of intraductal papillary mucinous neoplasm.
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To examine CT patterns of intraductal papillary mucinous neoplasm (IPMN), analyze their correlation with pathologic classification, and discuss the value of CT in the diagnosis and differential diagnosis of IPMN. CT patterns of 39 IPMN patients, whose clinical data were complete and whose diagnosis was confirmed by surgery and pathology, were classified into three types: (1) simple main pancreatic duct (MPD) dilation type, (2) MPD dilation with pancreatic cystic lesion type, and (3) simple pancreatic cystic lesion type. Correlations between the three CT types and Takada pathologic classification (MPD type, furcation type and mixture type) were analyzed. The 39 IPMN cases were pathologically classified as the benign group and the malignant/borderline group. CT characteristics including the presence or absence of mural nodules, intrafocal partitions, focal size and the degree of MPD and common bile duct (CBD) dilation were analyzed statistically. A correlation was found between the CT simple MPD dilation type and the pathological MPD type, between the MPD dilation with pancreatic cystic lesion type and the furcation and mixture types, and between the simple cystic lesion type and the furcation type (p<0.001). The benign rate was 92% in patients without intrafocal mural nodules, and 42% in patients with intrafocal mural nodules. The difference between the two groups was statistically significant (p=0.003). The presence or absence of intrafocal partitions was not correlated with benignancy or malignancy (p=0.793). The maximum diameter of malignant/borderline lesions was bigger than that of benign ones (p=0.016). There was no significant difference in MPD and CBD diameters between the benign and malignant/borderline groups. Regardless of pathological classification, the MPD diameter was larger than the CBD diameter in all cases (p=0.02). The three CT types of IPMN well correlated with the pathologic classification, which is helpful for analyzing CT manifestations and improving the accuracy of diagnosis. MPD dilation is usually larger than CBD dilation in IPMN patients, which is also helpful in the diagnosis and differential diagnosis of IPMN in the context of other related findings.
| 19,008,065
|
Research on the diffusion of evidence-based treatments within substance abuse treatment: a systematic review.
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This article provides a comprehensive review of research studies that have examined the diffusion of evidence-based treatments (EBTs) within the field of substance abuse treatment. Sixty-five research studies were identified and were grouped into one of three major classifications: attitudes toward EBTs, adoption of EBTs, and implementation of EBTs. This review suggests significant progress has been made with regard to the advancement of the fields' knowledge about attitudes toward and the extent to which specific EBTs have been adopted in practice, as well as with regard to the identification of organizational factors related to EBT adoption. In an effort to advance the substance abuse treatment field toward evidence-based diffusion practices, recommendations are made for greater use of methodologically rigorous experimental or quasi-experimental designs, psychometrically sound instruments, and integration of quantitative and qualitative data collection.
| 19,008,068
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[A survey of neuromuscular relaxant use from anaesthesiology residents in training].
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There is need to assess our practice of neuromuscular monitoring according to national consensus guidelines. The aim of this study was to evaluate practice adherence to guidelines in teaching hospitals. A questionnaire designed to provide information concerning the use of muscle relaxant for tracheal intubation and surgery, monitoring and antagonism of neuromuscular blockade in teaching hospital was distributed to anaesthesiology residents in training. Among 187 residents, 121 (65%) answered the questionnaire. A neuromuscular transmission monitoring device was reported available in each operating room by 56% (CI 95%: 46-65%) of responders. For tracheal intubation, neuromuscular monitoring was rarely or never used in 54% (CI 95%: 45-63%) of the responses. During the perioperative period and before extubation, neuromuscular monitoring was reported to be used by 56% (CI 95%: 46-65%) and 70% (CI 95%: 60-78%) of the residents respectively. The correct train-of-four ratio (T4/T1> or =0.9) required prior to extubation was respected in 55% (CI 95%: 46-64%) of the responses. When indicated, reversal of neuromuscular blockade was declared to be systematically performed by 49% (CI 95%: 40-58%) of responders. This questionnaire addressed to anaesthesiology residents in training was a practical and objective mean to obtain relevant information concerning our practices. It revealed an inadequate availability of quantitative neuromuscular monitors in the operating room. As a result, neuromuscular monitoring and reversal of neuromuscular blockade were underused. Teaching hospitals should improve their implication in residents' education and adherence to practice guidelines.
| 19,008,070
|
Patients were more consistent in randomized trial at prioritizing childbirth preferences using graphic-numeric than verbal formats.
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We developed an evidence-based decision aid to help women with a prior cesarean to prioritize their childbirth preferences related to a future birth. Because there was uncertainty about which scale format would assist the patients in being most consistent in prioritizing preferences in a multiattribute decision model, we compared a graphic-numeric scale with a text-anchored scale. Ninety-six postnatal women with a prior cesarean were randomized to use 1 of 2 preference scale formats in a computerized childbirth decision aid. We measured the level of inconsistency (intransitivity) when patients prioritized their childbirth preferences and clarity of values before and after using the decision aid. When the trade-offs involved risk, women were more consistent when using graphic-numeric than text-anchored formats (P=0.015). They prioritized safety to their baby as 4 times more important than any other decision factor including safety to self. Both groups reduced unclear childbirth values over time (P<0.001). Women who over-used the extreme ends of the scale when evaluating risk were more likely to be inconsistent (P<0.001). Patients were more consistent in making trade-offs involving risk using graphic-numeric formats than text-anchored formats to measure patient preferences.
| 19,008,073
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Mesenchymal stem cell differentiation on microstructured poly (methyl methacrylate) substrates.
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Recent studies on 2D substrates have revealed the importance of surface properties in affecting cell behaviour. In particular, surface topography appears to influence and direct cell migration. The development of new technologies of hot embossing and micro-imprinting has made it possible to study cell interactions with controlled micro features and to determine how these features can affect cell behaviour. Several studies have been carried out on the effect of microstructures on cell adhesion, cell guidance and cell proliferation. However, there is still a lack of knowledge on how these features affect mesenchymal stem cell differentiation. This study was designed to evaluate whether highly controlled microstructures on PMMA could induce rMSC differentiation into an osteogenic lineage. Structured PMMA was seeded with rMSC and cell number; cell morphology and cell differentiation were evaluated. Results confirm that microstructures not only affect cell proliferation and alignment but also have a synergistic effect with osteogenic medium on rMSC differentiation into mature osteoblasts.
| 19,008,086
|
Development of lightweight aggregate from dry sewage sludge and coal ash.
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In this study, dry sewage sludge (DSS) as the principal material was blended with coal ash (CA) to produce lightweight aggregate. The effects of different raw material compositions and sintering temperatures on the aggregate properties were then evaluated. In addition, an environmental assessment of the lightweight aggregate generated was conducted by analyzing the fixed rate of heavy metals in the aggregate, as well as their leaching behavior. The results indicated that using DSS enhanced the pyrolysis-volatilization reaction due to its high organic matter content, and decreased the bulk density and sintering temperature. However, the sintered products of un-amended DSS were porous and loose due to the formation of large pores during sintering. Adding CA improved the sintering temperature while effectively decreasing the pore size and increasing the compressive strength of the product. Furthermore, the sintering temperature and the proportion of CA were found to be the primary factors affecting the properties of the sintered products, and the addition of 18-25% of CA coupled with sintering at 1100 degrees C for 30 min produced the highest quality lightweight aggregates. In addition, heavy metals were fixed inside products generated under these conditions and the As, Pb, Cd, Cr, Ni, Cu, and Zn concentrations of the leachate were found to be within the limits of China's regulatory requirements.
| 19,008,090
|
Lipid II: a central component in bacterial cell wall synthesis and a target for antibiotics.
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The bacterial cell wall is mainly composed of peptidoglycan, which is a three-dimensional network of long aminosugar strands located on the exterior of the cytoplasmic membrane. These strands consist of alternating MurNAc and GlcNAc units and are interlinked to each other via peptide moieties that are attached to the MurNAc residues. Peptidoglycan subunits are assembled on the cytoplasmic side of the bacterial membrane on a polyisoprenoid anchor and one of the key components in the synthesis of peptidoglycan is Lipid II. Being essential for bacterial cell survival, it forms an attractive target for antibacterial compounds such as vancomycin and several lantibiotics. Lipid II consists of one GlcNAc-MurNAc-pentapeptide subunit linked to a polyiosoprenoid anchor 11 subunits long via a pyrophosphate linker. This review focuses on this special molecule and addresses three questions. First, why are special lipid carriers as polyprenols used in the assembly of peptidoglycan? Secondly, how is Lipid II translocated across the bacterial cytoplasmic membrane? And finally, how is Lipid II used as a receptor for lantibiotics to kill bacteria?
| 19,008,088
|
Peptide deformylase inhibitors of Mycobacterium tuberculosis: synthesis, structural investigations, and biological results.
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Bacterial peptide deformylase (PDF) belongs to a subfamily of metalloproteases catalyzing the removal of the N-terminal formyl group from newly synthesized proteins. We report the synthesis and biological activity of highly potent inhibitors of Mycobacterium tuberculosis (Mtb) PDF enzyme as well as the first X-ray crystal structure of Mtb PDF. Structure-activity relationship and crystallographic data clarified the structural requirements for high enzyme potency and cell based potency. Activities against single and multi-drug-resistant Mtb strains are also reported.
| 19,008,098
|
Construction of a fusion protein expression vector pGS/2SS-M4GFP without antibiotic resistance gene and its subcellular localization in different cell lines.
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A novel plasmid pGS/2SS-M4GFP was constructed in the present study by recombination of GS/2SS gene and enhanced green fluorescent protein (M4GFP) sequence. The GS/2SS fusion gene encoding two copies of somatostatin genes was firstly introduced into pVAX-asd vector in which the kanamycin resistance cassette was replaced by the asd cassette. The M4GFP gene was then fused into 3' end of GS/2SS gene in the proper reading frame. After purified, plasmid pGS/2SS-M4GFP was transfected into different cell lines derived from pig kidney and human cancer cells. The transcription process of GS/2SS gene was confirmed by RT-PCR, and the localization as well as expression of GS/2SS-M4GFP fusion protein was observed by confocal microscopy and ELISA. Transfection results revealed that sole M4GFP was localized within the cytosol and the nucleus, while fusion protein GS/2SS-M4GFP was localized only in the cytoplasm. Furthermore, it should be noted that subcellular localization of GS/2SS-M4GFP was not specific to one cell line, but appeared to be common across a variety of cell lines. These results provide for the first time valuable evidence that M4GFP is a versatile tool to trace GS/2SS protein and pave the way for further study on its tissue distribution and immunological mechanism in vivo.
| 19,008,122
|
Polyclonal hypergammaglobulinemia and high smooth-muscle autoantibody titers with specificity against filamentous actin: consider visceral leishmaniasis, not just autoimmune hepatitis.
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Visceral leishmaniasis (VL) remains a public health problem in most countries bordering the Mediterranean basin. Its diagnosis is challenging and often delayed, as the main clinical picture is often indistinguishable from that of other infectious and non-infectious diseases. Herein, we report two unusual cases of VL that presented with several characteristics of autoimmune hepatitis (AIH). Neither patient had a history of fever, only generalized symptoms accompanied by polyclonal hypergammaglobulinemia, cytopenias, signs of portal hypertension, elevated transaminases, and high titers of antinuclear and smooth-muscle autoantibodies (SMA) with reactivity against filamentous actin (F-actin), which has been recognized as specific to AIH. A clinical diagnosis of AIH was considered, but a bone marrow biopsy was performed before a liver biopsy to exclude a primary bone marrow disease. The biopsy led to the diagnosis of VL. The diagnosis was further confirmed by IgG antibodies against Leishmania spp. using ELISA and PCR-based assays. Treatment with amphotericin in the first case and pentamidine in the second (because of a severe reaction to amphotericin) was effective. From the clinical point of view, it should be emphasized that, in cases with high titers of anti-F-actin AIH-specific SMA accompanied by polyclonal hypergammaglobulinemia, the possibility of AIH should be cautiously differentiated from VL; this distinction is of paramount importance because initiation of immunosuppression for AIH treatment would be detrimental to a patient with underlying leishmaniasis. Therefore, in such cases and in areas where the disease is still present, it seems rational to exclude VL before starting any immunosuppressive therapy.
| 19,008,139
|
Somatic hypermutation of immunoglobulin genes: lessons from proliferating cell nuclear antigenK164R mutant mice.
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Proliferating cell nuclear antigen (PCNA) encircles DNA as a ring-shaped homotrimer and, by tethering DNA polymerases to their template, PCNA serves as a critical replication factor. In contrast to high-fidelity DNA polymerases, the activation of low-fidelity translesion synthesis (TLS) DNA polymerases seems to require damage-inducible monoubiquitylation (Ub) of PCNA at lysine residue 164 (PCNA-Ub). TLS polymerases can tolerate DNA damage, i.e. they can replicate across DNA lesions. The lack of proofreading activity, however, renders TLS highly mutagenic. The advantage is that B cells use mutagenic TLS to introduce somatic mutations in immunoglobulin (Ig) genes to generate high-affinity antibodies. Given the critical role of PCNA-Ub in activating TLS and the role of TLS in establishing somatic mutations in immunoglobulin genes, we analysed the mutation spectrum of somatically mutated immunoglobulin genes in B cells from PCNAK164R knock-in mice. A 10-fold reduction in A/T mutations is associated with a compensatory increase in G/C mutations-a phenotype similar to Poleta and mismatch repair-deficient B cells. Mismatch recognition, PCNA-Ub and Poleta probably act within one pathway to establish the majority of mutations at template A/T. Equally relevant, the G/C mutator(s) seems largely independent of PCNAK(164) modification.
| 19,008,189
|
Immunoglobulin class switch recombination: study through human natural mutants.
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Immunoglobulin class switch recombination deficiencies in humans are exquisite models to analyse the mechanisms of class switch recombination (CSR). Besides defects in CD40L/CD40 interaction, others result from an intrinsic B-cell deficiency. The recent elucidation of the molecular basis of some of them has made it possible to delineate the molecular events involved in antibody maturation. Activation-induced (cytidine) deaminase (AID) and uracil-N-glycosylase deficiencies have demonstrated the role of AID as the inducer of DNA lesions in switch and variable regions. However, most of these CSR deficiencies remain molecularly undefined. Their characterization would lead to a better understanding of the complex machinery involved in CSR.
| 19,008,192
|
APOBEC3G: an intracellular centurion.
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The intrinsic antiretroviral factor APOBEC3G (A3G) is highly active against HIV-1 and other retroviruses. In different cell types, A3G is expressed in high-molecular-mass (HMM) RNA- protein complexes or low-molecular-mass (LMM) forms displaying different biological activities. In resting CD4 T cells, a LMM form of A3G potently restricts HIV-1 infection soon after virion entry. However, when T cells are activated, LMM A3G is recruited into HMM complexes that include Staufen-containing RNA granules. These complexes are probably nucleated by the induced expression of Alu/hY retroelement RNAs that accompany T-cell activation. HMM A3G sequesters these retroelement RNAs away from the nuclear long interspersed nuclear element-derived enzymes required for Alu/hY retrotransposition. Human immunodeficiency virus (HIV) exploits this 'window of opportunity' provided by the loss of LMM A3G in activated CD4 T cells to productively infect these cells. During HIV virion formation, newly synthesized LMM A3G is preferentially encapsidated but only under conditions where Vif is absent and thus not able to target A3G for proteasome-mediated degradation. Together, these findings highlight the discrete functions of the different forms of A3G. LMM A3G opposes the external threat posed by exogenous retroviruses, while HMM A3G complexes oppose the internal threat posed by the retrotransposition of select types of retroelements.
| 19,008,196
|
Cephalopod dynamic camouflage: bridging the continuum between background matching and disruptive coloration.
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Individual cuttlefish, octopus and squid have the versatile capability to use body patterns for background matching and disruptive coloration. We define--qualitatively and quantitatively--the chief characteristics of the three major body pattern types used for camouflage by cephalopods: uniform and mottle patterns for background matching, and disruptive patterns that primarily enhance disruptiveness but aid background matching as well. There is great variation within each of the three body pattern types, but by defining their chief characteristics we lay the groundwork to test camouflage concepts by correlating background statistics with those of the body pattern. We describe at least three ways in which background matching can be achieved in cephalopods. Disruptive patterns in cuttlefish possess all four of the basic components of 'disruptiveness', supporting Cott's hypotheses, and we provide field examples of disruptive coloration in which the body pattern contrast exceeds that of the immediate surrounds. Based upon laboratory testing as well as thousands of images of camouflaged cephalopods in the field (a sample is provided on a web archive), we note that size, contrast and edges of background objects are key visual cues that guide cephalopod camouflage patterning. Mottle and disruptive patterns are frequently mixed, suggesting that background matching and disruptive mechanisms are often used in the same pattern.
| 19,008,200
|
p120 catenin recruits cadherins to gamma-secretase and inhibits production of Abeta peptide.
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The gamma-secretase complex cleaves many transmembrane proteins, including amyloid precursor protein, EphB and ErbB tyrosine kinase receptors, Notch1 receptors, and adhesion factors. Presenilin 1, the catalytic subunit of gamma-secretase, associates with the cadherin/catenin cell-cell adhesion/communication system and promotes cadherin processing (Georgakopoulos, A., et al. (1999) Mol. Cell 4, 893-902; Marambaud, P., et al. (2002) EMBO J. 21, 1948-1956), but the mechanism by which gamma-secretase and cadherins associate is unclear. Here we report that p120 catenin (p120ctn), a component of the cadherin-catenin complex, recruits gamma-secretase to cadherins, thus stimulating their processing while inhibiting production of Abeta peptide and the amyloid precursor protein intracellular domain. This function of p120ctn depends on both p120ctn-cadherin and p120ctn-presenilin 1 binding, indicating that p120ctn is the central factor that bridges gamma-secretase and cadherin-catenin complexes. Our data show that p120ctn is a unique positive regulator of the gamma-secretase processing of cadherins and a negative regulator of the amyloid precursor protein processing. Furthermore, our data suggest that specific members of the gamma-secretase complex may be used to recruit different substrates and that distinct PS1 sequences are required for processing of APP and cadherins.
| 19,008,223
|
Evaluation of spatiotemporal organization of persistent atrial fibrillation with time- and frequency-domain measures in humans.
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Areas with complex fractionated electrograms are commonly targeted during ablation of persistent atrial fibrillation (AF). These signals are, however, found in most sampled areas of the left atrium (LA), implying the need for further differentiation. Electrograms were recorded over 60 s at eight different LA endocardial sites in 10 patients with persistent AF, using a fully automated algorithm. These were analysed in sequential 2 s segments for activity, mean amplitude, continuous activity percentage, and dominant frequency (DF). All three time-domain measures differed significantly between the LA sites (P < 0.001), whereas DF did not. Activity, continuous activity percentage, and mean activity-amplitude were highest in the mid-coronary sinus and lowest on the posterior wall. In a pairwise analysis, there were significant differences in activity between all locations (P < 0.001-0.044). To visualize the spatiotemporal activity patterns, activity was plotted against amplitude. This revealed distinct activity patterns with large intra- and inter-individual differences. There are significant activity gradients and distinct activity patterns within the LA in humans with persistent AF. Further work is required, however, to determine whether these findings signify areas with different roles and importance in AF maintenance.
| 19,008,240
|
Quantitative analysis of elevated serum Golgi protein-73 expression in patients with liver diseases.
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Golgi protein-73 (GP73) is a newly identified candidate serum marker for liver diseases. The utility of this biomarker remains limited, largely due to the lack of quantitative information. The aims of this study were to quantify serum GP73 (sGP73) in healthy individuals and in patients with liver diseases, and to validate sGP73 as a biomarker for early diagnosis of liver disease. Recombinant GP73 was used to generate monoclonal (mAb) and polyclonal antibodies (pAb). Using these antibodies in a quantitative enzyme-linked immunosorbent assay, GP73 was measured in serum from 263 patients with various forms of liver and other diseases. The median sGP73 in patients with liver disease was significantly higher (P < 0.001) than in healthy individuals and in patients with other diseases. When sGP73 was used to detect liver disease, it had a sensitivity of 82% and a specificity of 80% at the optimal cut-off value of 85.5 microg/L. The area under the receiver-operating characteristic curve was 0.9. sGP73 concentration in patients with liver disease was three-fold higher than in healthy individuals. However, sGP73 concentrations did not differ significantly between patients from each liver disease group. Furthermore, sGP73 was not significantly elevated in patients with diseases other than liver disease compared with healthy individuals. These results suggest that sGP73 may be used as a serum marker for the diagnosis of liver disease.
| 19,008,260
|
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