Yan Chen

OBJECTIVE: To evaluate the association between 25-hydroxyvitamin D [25(OH)D] and metabolic syndrome in the Chinese population. RESEARCH DESIGN AND METHODS: Plasma 25(OH)D was measured in a cross-sectional sample of 1,443 men and 1,819 women aged 50-70 years from Beijing and Shanghai. Metabolic syndrome was defined according to the updated National Cholesterol Education Program Adult Treatment Panel III criteria for Asian Americans. Fasting plasma glucose, insulin, lipid profile, A1C, and inflammatory markers were measured. RESULTS: The geometric mean of plasma 25(OH)D was 40.4 nmol/l, and percentages of vitamin D deficiency [25(OH)D <50 nmol/l] and insufficiency [50 <or= 25(OH)D <75 nmol/l] were 69.2 and 24.4%, respectively. Compared with the highest 25(OH)D quintile (>or=57.7 nmol/l), the odds ratio for metabolic syndrome in the lowest quintile (<or=28.7 nmol/l) was 1.52 (95% CI 1.17-1.98, P(trend) = 0.0002) after multiple adjustment. Significant inverse associations also existed between 25(OH)D and individual metabolic syndrome components plus A1C. Moreover, we observed significant inverse associations of 25(OH)D with fasting insulin and the insulin resistance index (homeostasis model assessment of insulin resistance [HOMA-IR]) in overweight and obese individuals (BMI >or=24 kg/m(2)) but not in their normal-weight counterparts (test for interaction: P = 0.0363 and 0.0187 for insulin and HOMA-IR, respectively). CONCLUSIONS: Vitamin D deficiency is common in the middle-aged and elderly Chinese population, and a low 25(OH)D level is significantly associated with an increased risk of having metabolic syndrome and insulin resistance. Prospective studies and randomized clinical trials are warranted to determine the role of 25(OH)D in the development of metabolic syndrome and related metabolic diseases.

A fluorescent probe, HKOCl-1, has been successfully developed for the detection of hypochlorous acid on the basis of a specific reaction with p-methoxyphenol. The formation of HOCl has been successfully detected not only in an abiotic system but also in an enzymatic system (myeloperoxidase/H2O2/Cl(-) system) and in living macrophage cells upon stimulation. This new probe might be used as an efficient tool for probing the roles HOCl plays in biological systems.

With advances in nanotechnology, pure silver has been recently engineered into nanometer-sized particles (diameter <100 nm) for use in the treatment of wounds. In conjunction with other studies, we previously demonstrated that the topical application of silver nanoparticles (AgNPs) can promote wound healing through the modulation of cytokines. Nonetheless, the question as to whether AgNPs can affect various skin cell types--keratinocytes and fibroblasts--during the wound-healing process still remains. Therefore, the aim of this study was to focus on the cellular response and events of dermal contraction and epidermal re-epithelialization during wound healing under the influence of AgNPs; for this we used a full-thickness excisional wound model in mice. The wounds were treated with either AgNPs or control with silver sulfadiazine, and the proliferation and biological events of keratinocytes and fibroblasts during healing were studied. Our results confirm that AgNPs can increase the rate of wound closure. On one hand, this was achieved through the promotion of proliferation and migration of keratinocytes. On the other hand, AgNPs can drive the differentiation of fibroblasts into myofibroblasts, thereby promoting wound contraction. These findings further extend our current knowledge of AgNPs in biological and cellular events and also have significant implications for the treatment of wounds in the clinical setting.

Hirschsprung's disease (HSCR), or aganglionic megacolon, is a congenital disorder characterized by the absence of enteric ganglia in variable portions of the distal intestine. RET is a well-established susceptibility locus, although existing evidence strongly suggests additional loci contributing to sporadic HSCR. To identify these additional genetic loci, we carried out a genome-wide association study using the Affymetrix 500K marker set. We successfully genotyped 293,836 SNPs in 181 Chinese subjects with sporadic HSCR and 346 ethnically matched control subjects. The SNPs most associated with HSCR were genotyped in an independent set of 190 HSCR and 510 control subjects. Aside from SNPs in RET, the strongest overall associations in plausible candidate genes were found for 2 SNPs located in intron 1 of the neuregulin1 gene (NRG1) on 8p12, with rs16879552 and rs7835688 yielding odds ratios of 1.68 [CI(95%):(1.40, 2.00), P = 1.80 x 10(-8)] and 1.98 [CI(95%):(1.59, 2.47), P = 1.12 x 10(-9)], respectively, for the heterozygous risk genotypes under an additive model. There was also a significant interaction between RET and NRG1 (P = 0.0095), increasing the odds ratio 2.3-fold to 19.53 for the RET rs2435357 risk genotype (TT) in the presence of the NRG1 rs7835688 heterozygote, indicating that NRG1 is a modifier of HSRC penetrance. Our highly significant association findings are backed-up by the important role of NRG1 as regulator of the development of the enteric ganglia precursors. The identification of NRG1 as an additional HSCR susceptibility locus not only opens unique fields of investigation into the mechanisms underlying the HSCR pathology, but also the mechanisms by which a discrete number of loci interact with each other to cause disease.

A fluorescent probe, HKGreen-2, has been developed based on a specific reaction between ketone and peroxynitrite (ONOO(-)). This probe is highly sensitive and selective for the detection of peroxynitrite not only in abiotic but also in biological systems. With this probe, we successfully detected peroxynitrite generated in murine macrophage cells activated by phorbol 12-myristate 13-acetate (PMA), interferon-gamma (IFN-gamma), and lipopolysaccharide (LPS). This new probe will be a useful tool for studying the roles of peroxynitrite in biological processes.