Oxidative status and serum leptin levels in obese prepubertal children

The prevalence of obesity in children has increased dramatically over the last 20-30 years in developed countries. The aim of this study was to evaluate the oxidative and antioxidant status and any correlation with leptin in obese prepubertal children. A cross-sectional study was made of healthy children from ten elementary schools in the province of Elazig, Eastern Turkey. Blood samples were drawn from children comprising obese and control groups, on a visit to their school in the morning after an overnight fast. The mean body mass index (BMI) was 24.03 +/- 4.09 kg/m(2) in the obese group and was 17.51 +/- 2.33 kg/m(2) in the control group. Mean plasma leptin concentration was significantly higher in the obese children. Homocysteine and malondialdehyde (MDA) levels were also significantly higher in the obese group. In contrast superoxide dismutase (SOD) and glutathione peroxidase activities were significantly decreased in the obese group (p < 0.001). In conclusion, in prepubertal obese children oxidative stress was increased and MDA and homocysteine levels were well correlated with serum leptin level and BMI. In contrast with the increase in oxidative stress, antioxidant activities of SOD and glutathione peroxidase were decreased in obese prepubertal children.     

Epidermal Growth Factor Receptor Inhibition Modulates the Microenvironment by Vascular Normalization to Improve Chemotherapy and Radiotherapy Efficacy

Background

Epidermal growth factor receptor (EGFR) inhibitors have shown only modest clinical activity when used as single agents to treat cancers. They decrease tumor cell expression of hypoxia-inducible factor 1-α (HIF-1α) and vascular endothelial growth factor (VEGF). Hypothesizing that this might normalize tumor vasculature, we examined the effects of the EGFR inhibitor erlotinib on tumor vascular function, tumor microenvironment (TME) and chemotherapy and radiotherapy sensitivity.

Methodology/Principal Findings

Erlotinib treatment of human tumor cells in vitro and mice bearing xenografts in vivo led to decreased HIF-1α and VEGF expression. Treatment altered xenograft vessel morphology assessed by confocal microscopy (following tomato lectin injection) and decreased vessel permeability (measured by Evan''s blue extravasation), suggesting vascular normalization. Erlotinib increased tumor blood flow measured by Power Doppler ultrasound and decreased hypoxia measured by EF5 immunohistochemistry and tumor O₂ saturation measured by optical spectroscopy. Predicting that these changes would improve drug delivery and increase response to chemotherapy and radiation, we performed tumor regrowth studies in nude mice with xenografts treated with erlotinib and either radiotherapy or the chemotherapeutic agent cisplatin. Erlotinib therapy followed by cisplatin led to synergistic inhibition of tumor growth compared with either treatment by itself (p<0.001). Treatment with erlotinib before cisplatin led to greater tumor growth inhibition than did treatment with cisplatin before erlotinib (p = 0.006). Erlotinib followed by radiation inhibited tumor regrowth to a greater degree than did radiation alone, although the interaction between erlotinib and radiation was not synergistic.

Conclusions/Significance

EGFR inhibitors have shown clinical benefit when used in combination with conventional cytotoxic therapy. Our studies show that targeting tumor cells with EGFR inhibitors may modulate the TME via vascular normalization to increase response to chemotherapy and radiotherapy. These studies suggest ways to assess the response of tumors to EGFR inhibition using non-invasive imaging of the TME.     

Examining the microanatomy of various fetal body parts using the orcein-picroindigocarmine staining method

It is difficult to distinguish muscle, vessel, nerve, fascia, tendon and many other structures in fetal sections. The aim of the study reported here was to research the practicability of orcein-picroindigocarmine staining for distinguishing anatomic structures in histological sections containing complex structures. Histological serial sections of hand, foot, head and neck of four 18- to 20-week old fetuses were used. Bone matrix was stained bright blue, collagen fibers tones of green to blue, elastic fibers brown, cartilage matrix tones of pink, and chondroblasts blue. Muscles and erythrocytes were stained yellow to green, epidermis reddish brown, skin appendices including hair and nail stained light yellow to green.     

Evaluation of Genetic Diversity in Lemons and Some of Their Relatives Based on SRAP and SSR Markers

Genetic diversity was evaluated by sequence-related amplified polymorphism (SRAP) and simple sequence repeat (SSR) markers among 45 lemons (Citrus limon (L.) Burm. f.), five citrons (Citrus medica L.), four rough lemons (Citrus jambhiri Lush), and two Citrus volkameriana accessions. Twenty-one SRAP primer combinations produced a total of 141 (77%) polymorphic fragments with an average of 6.7 fragments per primer combinations whereas 13 SSR primers produced a total of 26 (76%) polymorphic fragments with an average of 2.0 per primer. The unweighted pair-group method arithmetic average analysis as assessed with combined SRAP and SSR data demonstrated that the accessions had a similarity range from 0.65 to 1.00. Rough lemons and C. volkameriana accessions were relatively closely related. In lemon group, accessions from hybrid origin were distant from the others. We also applied principal components analysis (PCA) for a better presentation of relation among the accessions studies. Using PCA, 88.7% of the total variation in the original dimensions could be represented by just the two dimensions defined by the first two PCs. Although nearly all accessions could be distinguished, there was a low level of genetic diversity detected among lemon cultivars.     

Chromosome 9p21 rs10757278 polymorphism is associated with the risk of metabolic syndrome

Metabolic syndrome (MetS) is a common multifactorial disorder that involves abdominal obesity, dyslipidemia, hypertension, and hyperglycemia. Genome-wide association studies have identified a major risk locus for coronary artery disease and myocardial infarction on chromosome 9p21. Here, we examined the frequency of single nucleotide polymorphisms (SNPs) on chromosome 9p21 in a sample of Turkish patients with MetS and further investigated the correlation between regional SNPs, haplotypes, and MetS. The real-time polymerase chain reaction (RT-PCR) was used to analyze 4 SNPs (rs10757274 A/G, rs2383207 A/G, rs10757278 A/G, rs1333049 C/G) in 291 MetS patients and 247 controls. Analysis of 4 SNPs revealed a significant difference in the genotype distribution for rs2383207, rs10757278, and rs1333049 between MetS patients and controls (p = 0.041, p = 0.005, p = 0.023, respectively) but not for rs10757274 (p = 0.211). MetS and control allelic frequencies for rs2383207, rs10757278, and rs1333049 were statistically different (p < 0.05). The rs2383207 AG variant, was identified as a MetS risk factor (p = 0.012, OR = 33.271; 95 % CI: 2.193–504.805) and the AA haplotype in block 1 and the GC, AG haplotypes in block 2 were associated with MetS (χ ² = 3.875, p = 0.049; χ ² = 9.334, p = 0.0022; χ ² = 9.134, p = 0.0025, respectively). In this study, we found that chromosome 9p21 SNP rs10757278 and related haplotypes correlate with MetS risk. This is the first report showing an association between a 9p21 variant and MetS and suggests that rs10757278 polymorphism may confer increased risk for disease.     

The association of MDR1 C3435T and G2677T/A polymorphisms with plasma platelet-activating factor levels and coronary artery disease risk in Turkish population

Increased levels of peripheral proinflammatory mediators can contribute to the development of coronary artery disease (CAD). Platelet activating factor (PAF) is an important proinflammatory mediator and plasma levels of PAF correlate with transmembrane transporter multidrug resistant 1 P-glycoprotein (MDR1 Pgp) expression and activity. MDR1 polymorphisms can affect the expression and activity of Pgp and plasma PAF levels. Therefore, we investigated the possible relationship between MDR1 C3435T and G2677T/A polymorphisms and plasma PAF levels and the risk of CAD. The study population consisted of 198 patients angiographically documented CAD, including 113 cases with at least 1 coronary artery with ≥ 50% luminal diameter stenosis and 85 control subjects with strictly normal coronary angiograms. Genotypes of the MDR1 C3435T and G2677T/A polymorphisms were determined by polymerase chain reaction (PCR) followed by restriction fragment length polymorphism (RFLP). Plasma PAF levels were detected by enzyme-linked immunosorbent assay (ELISA). There were no significant differences among plasma PAF levels in regard to MDR1 C3435T and G2677T polymorphisms in CAD patients and controls. No statistically significant difference was found for the genotypic and allelic distributions of the polymorphisms in the MDR1 gene between the patients and the control subjects. Furthermore, analysis of MDR1 haplotypes did not show any associations with increased plasma PAF levels and risk of CAD. Our results suggest that plasma PAF levels are not associated with MDR1 gene polymorphisms. There is no association between MDR1 C3435T and G2677T/A polymorphisms and the risk of CAD in Turkish patients.     

Timing and targeting of P-element local transposition in the male germline cells of Drosophila melanogaster

The P element in Drosophila melanogaster preferentially transposes into nearby sites. The local insertions display a preferential orientation toward the starting element. We investigated the mechanism of the P-element local transposition by isolating and characterizing local insertions in the male germline. We designed a genetic screen employing a marker gene that is carried in the P element and is dose sensitive. This dose effect allows isolation of flies containing newly transposed P elements in the presence of the starting element. A rapid molecular screen with PCR was used to identify 45 local insertions located within an approximately 40-kb genomic region on both sides of the starting element. Our system permits the isolation of the cluster progeny derived from a single insertion event, but none was isolated. The data suggest that local transposition occurs in the meiotic cell cycle. Nearly all of the local insertions were located within the promoter regions of the genes that were active in the male germline cells, suggesting that local insertions target predominantly active promoters. Our analysis shows that local transposition of the P element is highly regulated, displaying a cell-type specificity and a target specificity.     

The effects of p38 gene silencing on breast cancer cells

p38 mitogen-activated protein kinases (MAPK) are members of the MAPK family that are activated by inflammatory cytokines and a variety of environmental stresses. It mediates various biological processes. p38 MAPK activity play important roles in tumour progression. Excessive p38 expression is observed in invasive breast cancers. The aim of the present study was to investigate whether the p38 siRNA transfection of breast cancer cells is a putative preventive treatment for human breast cancer. p38 siRNA was used at a concentration of 15, 30, and 100 nM in human breast cancer cell lines (MCF-7) and normal fibroblast cell lines (NIH 3T3). After 48 and 72 h of transfection, the reduction in p38 expression was measured using quantitative real-time PCR. The activation of p38 signalling was measured by ELISA. XTT cell proliferation assay was performed to determine the effect of p38 silencing on MCF-7 and NIH 3T3 cell lines. The results demonstrated that approximately 96 % gene silencing occurred by the selected siRNA targeting p38 mRNA. The most effective silencing was observed at 72 h post-transfection using 30 nM p38 siRNA. The results of ELISA showed that the expression of p38 protein was inhibited by p38 siRNA at 30 nM siRNA and 100 nM at 72 h post transfection. XTT results showed that cells stimulated by 30 nM siRNA at 72 h post transfection were the lowest in proliferation. p38 siRNA can interfere with the expression of p38 at protein level in MCF-7 cells, result in inhibition of cell proliferation. p38 siRNA may be a critical regulator to promote the proliferation and protein expression in MCF-7 cells. In this study, we demonstrate that p38 silencing is a preventive maintenance for treating breast cancer.     

Comparative study of the energetics of ion permeation in Kv1.2 and KcsA potassium channels

Biological ion channels rely on a multi-ion transport mechanism for fast yet selective permeation of ions. The crystal structure of the KcsA potassium channel provided the first microscopic picture of this process. A similar mechanism is assumed to operate in all potassium channels, but the validity of this assumption has not been well investigated. Here, we examine the energetics of ion permeation in Shaker Kv1.2 and KcsA channels, which exemplify the six-transmembrane voltage-gated and two-transmembrane inward-rectifier channels. We study the feasibility of binding a third ion to the filter and the concerted motion of ions in the channel by constructing the potential of mean force for K⁺ ions in various configurations. For both channels, we find that a pair of K⁺ ions can move almost freely within the filter, but a relatively large free-energy barrier hinders the K⁺ ion from stepping outside the filter. We discuss the effect of the CMAP dihedral energy correction that was recently incorporated into the CHARMM force field on ion permeation dynamics.