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Abstract: Objective: Central obesity is considered to be a central component of metabolic syndrome. Waist circumference (WC) has been widely used as a simple indicator of central obesity. This study is aimed to evaluate the sensitivity of WC cut-off values for predicting metabolic risk factors in middle-aged Chinese. Methods: The study involved 923 subjects aged 40–65 years. The metabolic risk factors were defined according to the Chinese Joint Committee for Developing Chinese Guidelines on Prevention and Treatment of Dyslipidemia in Adults. WC cut-off 85–90 cm and ≥90 cm were used as cut-off values of central pre-obesity and central obesity in males, respectively, while WC 80–85 cm and ≥85 cm were used as cut-off values of central pre-obesity and central obesity in females. Results: First, WC values corresponding to body mass index (BMI) 24 kg/m2 and visceral fat area (VFA) 80 cm2 were 88.55 cm and 88.51 cm in males, and 81.46 cm and 82.51 cm in females respectively. Second, receiver operating characteristic curves showed that the optimal WC cut-off of value was 88.75 cm in males, higher than that in females (81.75 cm). Third, the subjects with higher WC values were more likely to have accumulating metabolic risk factors. The prevalence of metabolic risk factors increased linearly and significantly in relation to WC levels. Conclusion: WC cut-off values of central pre-/central obesity are optimal to predict multiple metabolic risk factors. [Copyright &y& Elsevier]

Objective: To investigate the effects of various HIV protease inhibitors on the function of pancreatic beta-cells., Methods: Rat insulinoma INS-1 cells were incubated with different concentrations of ritonavir or amprenavir for 48 h and stimulated with 20 mmol/L D-glucose for 30 min. The rate of insulin release was measured in the supernatant by ELISA, normalized to cellular DNA contents. Cells were counted with trypan blue and MTT test were determined to evaluate the effect of protease inhibitors on cell viability., Result: Ritonavir treatment significantly decreased baseline insulin release and glucose-stimulated insulin release in a dose-dependent manner (r=-0.861, -0.839, both P<0.01). For 10 micromol/L of ritonavir, the decrease rate of baseline insulin secretion and glucose-stimulated insulin secretion was 46% and 47%, respectively. Amprenavir had no effect on the rate of insulin release., Conclusion: Various HIV protease inhibitors present different effect on the insulin release of pancreatic beta-cells.

Objective: To investigate whether HIV-1 protease inhibitor nelfinavir alters the insulin stimulated phosphorylation of insulin signaling parameters in rat insulinoma INS-1 cells., Methods: INS-1 cells were incubated with nelfinavir for 48 h and stimulated with 100 nmol/L insulin for 2 min. Immunoprecipitation and Western blot analysis of the insulin stimulated insulin receptor substrate (IRS)-1,-2 and Akt-Thr(308) phosphorylation were performed on cell lysates. Cytotoxic effects of nelfinavir were measured by cell count with trypan blue and MTT reduction test., Result: Nelfinavir decreased insulin stimulated phosphorylation of IRS-2 and Akt-Thr(308) in a dose-dependent manner; for 10 micromol/L of nelfinavir, the decrease was 52% and 55%, respectively., Conclusion: Treatment with nelfinavir might impair IRS-2-mediated signaling in pancreatic beta cells.