Kinetic studies on the inhibition of GABA-T by gamma-vinyl GABA and taurine

Gamma-aminobutyric acid transaminase (GABA-T, EC 2.6.1.19) is a pyridoxal phosphate (PLP) dependent enzyme that catalyzes the degradation of gamma-aminobutyric acid. The kinetics of this reaction are studied in vitro, both in the absence, and in the presence of two inhibitors: gamma-vinyl GABA (4-aminohex-5-enoic acid), and a natural product, taurine (ethylamine-2-sulfonic acid). A kinetic model that describes the transamination process is proposed. GABA-T from Pseudomonas fluorescens is inhibited by gamma-vinyl GABA and taurine at concentrations of 51.0 and 78.5 mM. Both inhibitors show competitive inhibition behavior when GABA is the substrate and the inhibition constant (Ki) values for gamma-vinyl GABA and taurine were found to be 26 +/- 3 mM and 68 +/- 7 mM respectively. The transamination process of alpha-ketoglutarate was not affected by the presence of gamma-vinyl GABA, whereas, taurine was a noncompetitive inhibitor of GABA-T when alpha-ketoglutarate was the substrate. The inhibition dissociation constant (Kii) for this system was found to be 96 +/- 10 mM. The Michaelis-Menten constant (Km) in the absence of inhibition, was found to be 0.79 +/- 0.11 mM, and 0.47 +/- 0.10 mM for GABA and alpha-ketoglutarate respectively.     

Goitrogenic activity of p-coumaric acid in rats

The effects of three natural phenolic acids (caffeic, ferulic, and p-coumaric) on the rat thyroid gland were examined in a 3-week oral-treatment study. Forty male Wistar albino rats, divided into groups of 10 rats each and fed iodine-rich diet, were administered by gastrointestinal tube saline (control), caffeic acid, ferulic acid, or p-coumaric acid at a dose level of 0.25 micromol/kg/day for 3 weeks. The mean absolute and relative thyroid weights in caffeic, ferulic, or p-coumaric acid groups were significantly increased to 127 and 132%, 146 and 153%, or 189 and 201% compared to control value, respectively. Histological examination of the thyroids of p-coumaric acid group revealed marked hypertrophy and/or hyperplasia of the follicles. Caffeic or ferulic groups showed slight to moderate thyroid gland enlargement. Thyroid lesions in p-coumaric acid group were associated with significant increases in cellular proliferation as indicated by [(3)H]thymidine incorporation. In addition, the goitrogenic effect of p-coumaric acid was further confirmed by significant decreases (50%) in serum tri-iodothyronine (T(3)) and thyroxine (T(4)), and a parallel increase (90%) in serum thyroid stimulating hormone (TSH) compared to control group. These results indicate that administration of p-coumaric acid at relatively high doses induces goiter in rats.     

Apigenin protects from hepatorenal damage caused by lead acetate in rats

Exposure to lead (Pb) is associated with serious health problems including hepatorenal toxicity. Apigenin is a natural-sourced flavonoid with promising antioxidant and anti-inflammatory effects. In this research, we investigated the potential protective role of apigenin against lead acetate (PbAc)-induced hepatorenal damage. Thus, this experiment studied the exposure of male Wistar Albino rats to apigenin and/or PbAc and their effects in comparison to the control rats. Apigenin administration decreased the levels of Pb and prevented the histopathological deformations in liver and kidney tissues following PbAc exposure. This was confirmed by the normalized levels of liver and kidney function markers. Additionally, apigenin inhibited significantly oxidative reactions through upregulating Nrf2 and HO-1, and activating their downstreamed antioxidants accompanied by a marked depletion of pro-oxidants. Moreover, apigenin decreased the elevated pro-inflammatory cytokines and inhibited cell loss in liver and kidney tissues in response to PbAc intoxication in both tissues. The obtained results demonstrated that apigenin could be used to attenuate the molecular, biochemical, and histological alterations associated with Pb exposure due to its potent antioxidant, anti-inflammatory, and antiapoptotic effects.     

Polycystic ovary syndrome is linked with the fat mass obesity (FTO) gene variants rs17817449 and rs1421085 in western Saudi Arabia

Polycystic ovary syndrome (PCOS) is characterised by infertility, obesity, insulin resistance and clinical and/or biochemical signs of hyperandrogenism. Obesity is known to be correlated with PCOS causing ovulatory dysfunction and hormone imbalances. Moreover, fat mass and the obesity gene (FTO) were linked with obesity and PCOS. Therefore, it is of interest to determine the genotype and allele frequency for three FTO variants - rs17817449 (G/T), rs1421085 (C/T) and rs8050136 (A/C) -in western Saudi population. 95 PCOS patients and 94 controls were recruited for this study. The genetic variants were assayed using real-time polymerase chain reaction using TaqMan genotyping assays. The chi-squared test was applied to investigate the difference between single nucleotide polymorphisms on PCOS and control subjects, and binary logistic regression was used to determine the association of FTO variants with PCOS symptoms. Variants rs17817449 and rs1421085 were significantly linked with PCOS susceptibility in the study population. Rs17817449 and rs8050136 were significantly associated with hair loss in the PCOS group. Furthermore, rs1421085 and rs8050136 were associated with a high body mass index (BMI>30 kg/m2). Risk alleles in our population associated with hair loss and elevated BMI in women with PCOS were homozygous C for rs8050136. This data will help in defining the genetic predisposition of PCOS among women in western Saudi Arabia.     

1,3,4-Oxadiazole-naphthalene hybrids as potential VEGFR-2 inhibitors: design,synthesis, antiproliferative activity,apoptotic effect,and in silico studies

In the current work, some 1,3,4-oxadiazole-naphthalene hybrids were designed and synthesised as VEGFR-2 inhibitors. The synthesised compounds were evaluated in vitro for their antiproliferative activity against two human cancer cell lines namely, HepG-2 and MCF-7. Compounds that exhibited promising cytotoxicity (5, 8, 15, 16, 17, and 18) were further evaluated for their VEGFR-2 inhibitory activities. Compound 5 showed good antiproliferative activity against both cell lines and inhibitory effect on VEGFR-2. Besides, it induced apoptosis by 22.86% compared to 0.51% in the control (HepG2) cells. This apoptotic effect was supported by a 5.61-fold increase in the level of caspase-3 compared to the control cells. Moreover, it arrested the HepG2 cell growth mostly at the Pre-G1 phase. Several in silico studies were performed including docking, ADMET, and toxicity studies to predict binding mode against VEGFR-2 and to anticipate pharmacokinetic, drug-likeness, and toxicity of the synthesised compounds.     

A Comparison of Weighted Tests for a Slope Change in Simple Regression

Testing for a change in the slope of the simple linear regression model has many applications in bio‐sciences, quality control and survival analysis. This paper compares Anderson‐Darling and Erdós‐Darling type test statistics which are based on the least squares change point process of Sen (1980) with the corresponding Kolmogorov‐Smirnov and Crámer‐von Mises type test statistics. We estimated the limiting critical values of these test statistics and conducted Monte Carlo simulation studies to compare their powers.     

Lectin-Like OLR1 3′UTR Rs1050286 Gene Polymorphism and Plasma Oxidized-LDL in Coronary Artery Disease and Their Relation to Cardiovascular Risk and Outcomes

Background:Oxidized low-density lipoprotein (ox-LDL) has an important role in the genesis of coronary atherosclerosis. Lectin-like ox-LDL receptor 1 (OLR1) contributes to the uptake and internalization of ox-LDL. Genetic polymorphisms have been associated with coronary artery disease (CAD). Here we explore the association of plasma levels of ox-LDL and 3′ UTR OLR1 (rs1050286) SNP with CAD risk and in-hospital adverse outcomes.Methods:A case-control study enrolled 192 patients with ST-segment elevation myocardial infarction (STEMI), 100 patients with unstable angina, and 100 healthy controls. Baseline, clinical characteristics, and risk scores of the patients were determined. Plasma ox-LDL and other biochemical variables were measured. All subjects are genotyped for OLR1 (rs1050286) by RT-PCR with TaqMan SNP genotyping assay.Results:Plasma ox-LDL was higher with enhanced sensitivity and specificity in identifying patients with STEMI and was found as a significant independent risk factor for CAD in those two groups. Levels of ox-LDL were increased with increasing poor prognostic factors in STEMI patients that are associated with an increased incidence of some adverse events and in-hospital mortality. Elevated STEMI risk was associated with T allele of OLR1 (rs1050286) (odds ratio of 4.9, 95% CI: 2.6-9.4, p< 0.001). STEMI patients who have T allele exhibited higher risk scores, coronary multivessel narrowing, and elevated incidence of in-hospital major adverse clinical events.Conclusion:These results suggest that plasma ox-LDL, as well as T allele of ORL-1 (rs1050286), is associated with the increased risk for developing STEMI and the associated adverse clinical outcomes.Key Words: Coronary artery disease, genotyping, OLR1, outcomes, Oxidized low-density lipoprotein     

Chemiluminescence determination of chlorpheniramine using tris(1,10‐phenanthroline)–ruthenium(II) peroxydisulphate system and sequential injection analysis

A sequential injection (SI) method was developed for the determination of chlorpheniramine (CPA), based on the reaction of this drug with tris(1,10‐phenanthroline)–ruthenium(II) [Ru(phen)₃²⁺] and peroxydisulphate (S₂O₈^2–) in the presence of light. The instrumental set‐up utilized a syringe pump and a multiposition valve to aspirate the reagents [Ru(phen)₃²⁺ and S₂O₈^2–] and a peristaltic pump to propel the sample. The experimental conditions affecting the chemiluminescence reaction were systematically optimized, using the univariate approach. Under the optimum conditions linear calibration curves of 0.1–10 µg/ml were obtained. The detection limit was 0.04 µg/ml and the relative standard deviation (RSD) was always < 5%. The procedure was applied to the analysis of CPA in pharmaceutical products and was found to be free from interferences from concomitants usually present in these preparations. Copyright © 2008 John Wiley & Sons, Ltd.     

Interleukin-10 and sudden infant death syndrome

Uncontrolled pro-inflammatory responses to infections or bacterial toxins have been suggested to play a role in triggering the physiological events leading to sudden infant death syndrome (SIDS). We tested the hypothesis that these uncontrolled responses might be due to interactions between the gene polymorphisms inducing low levels of IL-10 and exposure to cigarette smoke. In vitro, the IL-10 (G-1082A) polymorphism was associated with low IL-10 levels and the -1082G allele was associated with high levels. The first objective was to assess the distribution of this polymorphism among SIDS infants, parents of SIDS infants and controls, and two ethnic groups: Aboriginal Australians who have a high incidence of SIDS; and Bangladeshis who in Britain have a low incidence of SIDS compared with Europeans. The second objective was to assess effects of human recombinant IL-10 on interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-alpha) responses of human leukocytes to staphylococcal toxins implicated in SIDS. The third objective was to assess IL-10 responses to endotoxin and toxic shock syndrome toxin (TSST) from leukocytes of smokers and non-smokers in relation to the IL-10 (G-1082A) polymorphism. There were major differences in the distributions of these polymorphisms between Europeans and Bangladeshis (p=0.00) and between Europeans and Aboriginal Australians (p=0.00); however, they were similar for the Bangladeshi and Aboriginal Australian subjects. There were no significant differences in the distribution of these polymorphisms among SIDS infants or parents of SIDS infants compared to control groups. IL-10 significantly reduced IL-6 and TNF-alpha responses to TSST and staphylococcal enterotoxins A and C. At 50 ng ml(-1), IL-10 significantly increased TNF-alpha but not IL-6 responses to TSST and enterotoxin A. Although IL-10 responses to endotoxin were lower from leukocytes of smokers who were homozygous for the G allele, the differences were not significant; however, significantly lower IL-10 responses were found for smokers who were homozygous for the A allele (p=0.01) and heterozygotes (p=0.04). The pooled data found smokers had significantly lower levels of IL-10 responses to TSST, but there were no significant differences for smokers compared with non-smokers for the three genotypes. The high incidence of SIDS and serious respiratory infections among Aboriginal Australian infants and the low incidence of these conditions among Bangladeshi infants might be explained in part by our findings of differences in IL-10 responses between smokers and non-smokers. The lowest levels of IL-10 responses were observed among smokers who were homozygous for the A allele which is most prevalent among the Aboriginal Australians (83%) and Bangladeshis (84%). The major difference between the risk factors for SIDS in these two groups is the level of exposure of infants to cigarette smoke associated with maternal smoking.