Duration-dependent effects of nicotine exposure on growth and AKT activation in human kidney epithelial cells

Exposure to nicotine is known to cause adverse effects in many target organs including kidney. Epidemiological studies suggest that nicotine-induced kidney diseases are prevalent worldwide. However, the impact of duration of exposure on the nicotine-induced adverse effects in normal kidney cells and the underlying molecular mechanism is still unclear. Hence, the objective of this study was to evaluate both acute and long-term effects of nicotine in normal human kidney epithelial cells (HK-2). Cells were treated with 1 and 10 µM nicotine for acute and long-term duration. The result of cell viability showed that the acute exposure to 1 µM nicotine has no significant effect on growth. However, the 10 µM nicotine caused significant decrease in the growth of HK-2 cells. The long-term exposure resulted in significantly increased cell growth in both 1 and 10 µM nicotine-treated groups. Analysis of cell cycle and expression of marker genes related to proliferation and apoptosis further confirmed the effects of nicotine. Additionally, the analysis of growth signaling pathway revealed the decreased level of pAKT in cells with acute exposure whereas the increased level of pAKT in long-term nicotine-exposed cells. This suggests that nicotine, through modulating the AKT pathway, controls the duration-dependent effects on the growth of HK-2 cells. In summary, this is the first report showing long-duration exposure to nicotine causes increased proliferation of human kidney epithelial cells through activation of AKT pathway.     

A Modified BFGS Formula Using a Trust Region Model for Nonsmooth Convex Minimizations

This paper proposes a modified BFGS formula using a trust region model for solving nonsmooth convex minimizations by using the Moreau-Yosida regularization (smoothing) approach and a new secant equation with a BFGS update formula. Our algorithm uses the function value information and gradient value information to compute the Hessian. The Hessian matrix is updated by the BFGS formula rather than using second-order information of the function, thus decreasing the workload and time involved in the computation. Under suitable conditions, the algorithm converges globally to an optimal solution. Numerical results show that this algorithm can successfully solve nonsmooth unconstrained convex problems.     

Inhibition of lipase-catalyzed hydrolysis of sunflower oil in AOT/isooctane reversed micelles

The hydrolysis of sunflower oil using Candida cylindracea lipase in reversed micelles of AOT/isooctane was investigated. The inhibition caused by substrate and hydrolysis products has been found in the process of reaction. It was revealed that the extent of inhibition caused by oleic acid was higher than that caused by glycerol, and was much more serious in the case of the mixture of hydrolysis products. Moreover, with the initial addition of glycerol into the reaction mixture, the stability of lipase could be increased during the hydrolysis of sunflower oil in reversed micelles. We thank the National Natural Science Foundation of China for the financial support of this work. We also thank Prof. Xu, Jia-li for his contributions to this work.     

四川雅安常见住区蝇类密度监测

根据全国常见住区蝇类密度监测课题组关于“全国常见住区蝇类密度监测实施计划”安排,雅安地区定力全国七个监测点之一,作者承担了这一任务。该项工作尚在继续进行中,现将1988年监测结果报道如下。     

Extracellular Dopamine, Norepinephrine, and Serotonin in the Nucleus Accumbens of Freely Moving Rats During Intracerebral Dialysis with Cocaine and Other Monoamine Uptake Blockers

Abstract: Monoamine-uptake blockers were applied focally (0.1–1,000 µ M ) through a dialysis probe in the nucleus accumbens of freely moving rats, and the extracellular concentrations of dopamine, norepinephrine, and serotonin were measured. The selective dopamine-uptake blocker GBR 12935 increased dopamine preferentially with only a small effect on norepinephrine, whereas the selective serotonin-uptake blocker fluoxetine increased serotonin output preferentially. In contrast, the selective norepinephrine-uptake blockers desipramine and nisoxetine enhanced not only norepinephrine, but also serotonin and dopamine appreciably. Cocaine increased all three amines with the greatest effects on dopamine and serotonin. As in our previous study on the ventral tegmental area, there was a positive association between dopamine and norepinephrine output when all blocker data were taken together. The present results suggest a contribution of the increase in norepinephrine, but not serotonin, to the enhancement of dopamine after cocaine applied focally in the nucleus accumbens.