1,577 research outputs found
Possible association of interleukin-1beta (-511C/T) and interleukin-6 (-174G/C) gene polymorphisms with atherosclerosis in end stage renal disease Egyptian patients on maintenance haemodialysis
In end stage renal disease, inflammation is considered a critical regulator of atherosclerotic plaque formation and progression, to which many dialysis and non-dialysis-related factors may contribute. Since circulating inflammatory cytokine levels vary inter-individually, one may speculate that genetic factors, such as polymorphisms in genes encoding them, may be involved in determining the individual inflammatory reaction in response to a given insult. The present work aimed to study interleukin-1B (-511C/T), and interleukin-6 (-174G/C) gene polymorphisms and their possible association with atherosclerosis in Egyptian patients with end stage renal disease on maintenance haemodialysis. The present study was conducted on 100 Egyptian subjects, the control group (n= 30) and the patient group (n= 70) with end stage renal disease on maintenance haemodialysis which were further subdivided into two subgroups with (n= 33) and without atherosclerosis (n= 37) as evidenced by CIMT, ECG ischaemic changes, cerebrovascular insufficiency (CVI), and peripheral vascular insufficiency (PVI). All studied subjects were subjected to detailed history taking, routine laboratory investigations and molecular studies including detection of IL-1B (-511C/T) and IL-6 (-174G/C) gene polymorphisms using the Polymerase chain reaction/ Restriction fragment length polymorphism (PCR/RFLP) technique. The genotype distribution and allele frequency of IL-1B (-511C/T) and IL-6 (-174G/C) showed no statistical significant difference among the studied groups. To conclude the development of atherosclerosis among Egyptian patients on maintenance haemodialysis cannot be attributed to these two gene polymorphisms
Sensitivity analysis of circadian entrainment in the space of phase response curves
Sensitivity analysis is a classical and fundamental tool to evaluate the role
of a given parameter in a given system characteristic. Because the phase
response curve is a fundamental input--output characteristic of oscillators, we
developed a sensitivity analysis for oscillator models in the space of phase
response curves. The proposed tool can be applied to high-dimensional
oscillator models without facing the curse of dimensionality obstacle
associated with numerical exploration of the parameter space. Application of
this tool to a state-of-the-art model of circadian rhythms suggests that it can
be useful and instrumental to biological investigations.Comment: 22 pages, 8 figures. Correction of a mistake in Definition 2.1. arXiv
admin note: text overlap with arXiv:1206.414
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Contribution of obesity to racial and ethnic disparities in the risk of fetal myelomeningocele: a population-based study.
BACKGROUND: Prepregnancy obesity and racial-ethnic disparities has been shown to be associated with meningomyelocele. OBJECTIVE: This study aimed to investigate the association of maternal periconceptional factors, including race-ethnicity and prepregnancy body mass index, with the prevalence of isolated fetal myelomeningocele. METHODS: This was a population-based cross-sectional study using Centers for Disease Control and Prevention birth data from 2016 to 2021. Major structural anomalies or chromosomal abnormalities were excluded. Race-ethnicity was classified as non-Hispanic White (reference population), non-Hispanic Black, non-Hispanic Asian, Hispanic, and others. Maternal prepregnancy body mass index was classified as underweight (<18.5 kg/m2), normal (reference group; 18.5-24.9 kg/m2), overweight (25-29.9 kg/m2), and class I (30-34.9 kg/m2), class II (35-39.9 kg/m2), and class III obesity (≥40 kg/m2). A chi-square test of independence was performed to identify factors significantly associated with myelomeningocele. These factors were then stratified into 3 adjusted clusters/levels. The prevalence was calculated per 10,000 live births. The Cochran-Armitage test for trend was used to detect any significant increasing or decreasing trends. RESULTS: A total of 22,625,308 pregnancies with live birth, including 2866 pregnancies with isolated fetal myelomeningocele, were included in the analysis. The prevalence of isolated fetal myelomeningocele per 10,000 live births varied among different racial/ethnic groups, with the highest prevalence found among the non-Hispanic White (1.60 [1.52-1.67]) and lowest among the non-Hispanic Asian (0.50 [0.40-0.64]) population. The prevalence significantly increased with body mass index, with the highest prevalence found in the population with class III obesity (1.88 per 10,000 live births). Subgroup analysis of the associations between the significant variables (obesity, diabetes, hypertension, and education) and each ethnicity in cases with myelomeningocele showed significant variations in prevalence of these variables among different racial/ethnic groups. Following the model with the 3 levels of adjustment described in the Methods section, prepregnancy overweight and class I, II, and III obesity remained significantly associated with the odds of isolated fetal myelomeningocele. The adjusted odds ratios were 1.32 (95% confidence interval, 1.19-1.46; P<.001) for overweight, 1.55 (95% confidence interval, 1.38-1.75; P<.001) for class I obesity, 1.68 (95% confidence interval, 1.45-1.94; P<.001) for class II obesity, and 1.73 (95% confidence interval, 1.47-2.04; P<.001) for class III obesity. Similarly, following the 3-level adjustment model, the obesity-mediated effect of maternal race-ethnicity on the odds of myelomeningocele remained significant (non-Hispanic Black: adjusted odds ratio, 1.03; 95% confidence interval, 1.02-1.05; P<.001; non-Hispanic Asian: adjusted odds ratio, 1.02; 95% confidence interval, 1.01-1.03; P<.001; Hispanic: adjusted odds ratio, 1.5; 95% confidence interval, 1.03-1.6; P<.001). The test for trend among different racial/ethnic groups did not show significant results across the past 6 years. However, the test for trend showed a significant increase in the prevalence of isolated myelomeningocele associated with class II and III obesity over the past 6 years. CONCLUSION: There has been a rising trend of fetal isolated myelomeningocele in pregnancies with maternal class II and III obesity over the past 6 years after adjusting for other covariates. Prepregnancy obesity, a modifiable risk factor, is a significant driver of racial/ethnic disparities in the overall risk for isolated fetal myelomeningocele
Vitellogenin Underwent Subfunctionalization to Acquire Caste and Behavioral Specific Expression in the Harvester Ant Pogonomyrmex barbatus
PMCID: PMC3744404This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication
Spatio-temporal Models of Lymphangiogenesis in Wound Healing
Several studies suggest that one possible cause of impaired wound healing is
failed or insufficient lymphangiogenesis, that is the formation of new
lymphatic capillaries. Although many mathematical models have been developed to
describe the formation of blood capillaries (angiogenesis), very few have been
proposed for the regeneration of the lymphatic network. Lymphangiogenesis is a
markedly different process from angiogenesis, occurring at different times and
in response to different chemical stimuli. Two main hypotheses have been
proposed: 1) lymphatic capillaries sprout from existing interrupted ones at the
edge of the wound in analogy to the blood angiogenesis case; 2) lymphatic
endothelial cells first pool in the wound region following the lymph flow and
then, once sufficiently populated, start to form a network. Here we present two
PDE models describing lymphangiogenesis according to these two different
hypotheses. Further, we include the effect of advection due to interstitial
flow and lymph flow coming from open capillaries. The variables represent
different cell densities and growth factor concentrations, and where possible
the parameters are estimated from biological data. The models are then solved
numerically and the results are compared with the available biological
literature.Comment: 29 pages, 9 Figures, 6 Tables (39 figure files in total
IFSS, TG, FT-IR spectra of impregnated sugar palm (Arenga pinnata) fibres and mechanical properties of their composites.
This study aimed to investigate the effect of resin impregnation on the interfacial shear strength (IFSS), thermogravimetric (TG) and fourier transform infrared (FT-IR) of sugar palm (Arenga pinnata) fibres. In addition, the effect of resin impregnation on the mechanical properties of sugar palm fibre reinforced unsaturated polyester (UP) composites was also studied. The fibres were impregnated with UP via vacuum resin impregnation process at a pressure of 600 mmHg for 5 min. Composites of 10, 20, 30, 40 and 50 % fibre loadings were fabricated and tested for tensile and flexural properties. It was observed that the impregnation process caused the fibres to be enclosed by UP resin and this gave a strong influence to the increase of its interfacial bonding by the increase of its IFSS from single fibre pull-out test. It was also observed with TG and FT-IR spectra that the impregnated fibre had lower moisture uptake than the control and there was no significant increase in thermal stability of the impregnated fibre. The sequence of fibre decomposition started from the evaporation of moisture, hemicelluloses, cellulose, lignin and finally ash content and the presence of these components were proven by FT-IR spectra. For the composite specimens, due to the high interfacial bonding of the impregnated fibre and the matrix, the impregnated composites showed consistently higher tensile strength, tensile modulus, elongation at break, flexural strength, flexural modulus and toughness than the control samples. It was also observed that 30 % fibre loading gave optimum properties
Molecular markers of anti-malarial drug resistance in Lahj Governorate, Yemen: baseline data and implications
<p>Abstract</p> <p>Background</p> <p>This is an investigation of anti-malarial molecular markers coupled with a therapeutic efficacy test of chloroquine (CQ) against falciparum malaria in an area of unstable malaria in Lahj Governorate, Yemen. The study was aimed at assessment of therapeutic response to CQ and elucidation of baseline information on molecular markers for <it>Plasmodium falciparum </it>resistance against CQ and sulphadoxine/pyrimethamine (SP).</p> <p>Methods</p> <p>Between 2002 and 2003 the field test was conducted according to the standard WHO protocol to evaluate the therapeutic efficacy of CQ in 124 patients with falciparum malaria in an endemic area in Lahj Governorate in Yemen. Blood samples collected during this study were analysed for <it>P. falciparum </it>chloroquine resistance transporter gene (<it>pfcrt</it>)-76 polymorphisms, mutation <it>pfcrt-</it>S163R and the antifolate resistance-associated mutations dihydrofolate reductase (<it>dhfr</it>)-C59R and dihydropteroate synthase (<it>dhps</it>)-K540E. Direct DNA sequencing of the <it>pfcrt </it>gene from three representative field samples was carried out after DNA amplification of the 13 exons of the <it>pfcrt </it>gene.</p> <p>Results</p> <p>Treatment failure was detected in 61% of the 122 cases that completed the 14-day follow-up. The prevalence of mutant <it>pfcrt </it>T76 was 98% in 112 amplified pre-treatment samples. The presence of <it>pfcrt </it>T76 was poorly predictive of <it>in vivo </it>CQ resistance (PPV = 61.8%, 95% CI = 52.7-70.9). The prevalence of <it>dhfr </it>Arg-59 mutation in 99 amplified samples was 5%, while the <it>dhps </it>Glu-540 was not detected in any of 119 amplified samples. Sequencing the <it>pfcrt </it>gene confirmed that Yemeni CQ resistant <it>P. falciparum </it>carry the old world (Asian and African) CQ resistant haplotype CVIETSESI at positions 72,73,74,75,76,220,271, 326 and 371.</p> <p>Conclusion</p> <p>This is the first study to report baseline information on the characteristics and implications of anti-malarial drug resistance markers in Yemen. It is also the first report of the haplotype associated with CQR <it>P. falciparum </it>parasites from Yemen. Mutant <it>pfcrt</it>T76 is highly prevalent but it is a poor predictor of treatment failure in the study population. The prevalence of mutation <it>dhfr</it>Arg59 is suggestive of emerging resistance to SP, which is currently a component of the recommended combination treatment of falciparum malaria in Yemen. More studies on these markers are recommended for surveillance of resistance in the study area.</p
Utilisation of an operative difficulty grading scale for laparoscopic cholecystectomy
Background
A reliable system for grading operative difficulty of laparoscopic cholecystectomy would standardise description of findings and reporting of outcomes. The aim of this study was to validate a difficulty grading system (Nassar scale), testing its applicability and consistency in two large prospective datasets.
Methods
Patient and disease-related variables and 30-day outcomes were identified in two prospective cholecystectomy databases: the multi-centre prospective cohort of 8820 patients from the recent CholeS Study and the single-surgeon series containing 4089 patients. Operative data and patient outcomes were correlated with Nassar operative difficultly scale, using Kendall’s tau for dichotomous variables, or Jonckheere–Terpstra tests for continuous variables. A ROC curve analysis was performed, to quantify the predictive accuracy of the scale for each outcome, with continuous outcomes dichotomised, prior to analysis.
Results
A higher operative difficulty grade was consistently associated with worse outcomes for the patients in both the reference and CholeS cohorts. The median length of stay increased from 0 to 4 days, and the 30-day complication rate from 7.6 to 24.4% as the difficulty grade increased from 1 to 4/5 (both p < 0.001). In the CholeS cohort, a higher difficulty grade was found to be most strongly associated with conversion to open and 30-day mortality (AUROC = 0.903, 0.822, respectively). On multivariable analysis, the Nassar operative difficultly scale was found to be a significant independent predictor of operative duration, conversion to open surgery, 30-day complications and 30-day reintervention (all p < 0.001).
Conclusion
We have shown that an operative difficulty scale can standardise the description of operative findings by multiple grades of surgeons to facilitate audit, training assessment and research. It provides a tool for reporting operative findings, disease severity and technical difficulty and can be utilised in future research to reliably compare outcomes according to case mix and intra-operative difficulty
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