Thiamine (Vitamin B1) protects against glucose- and insulin-mediated proliferation of human infragenicular arterial smooth muscle cells

Accelerated proliferation of arterial smooth muscle cells (ASMC) plays an important role in the development of atherosclerosis, which preferentially affects the infragenicular vasculature in patients with diabetes mellitus. High insulin and glucose levels, which are present in patients with type II diabetes, have an additive effect in infragenicular ASMC proliferation in vitro. Thiamine is a coenzyme important in intracellular glucose metabolism. The objective of this study is to determine the effect of thiamine on human infragenicular ASMC proliferation induced by high glucose and insulin levels in vitro. Human infragenicular ASMC isolated from diabetic patients undergoing lower extremity amputation were used. Cells were cultured at 37°C in 5% CO2. Cells were identified as ASMC by immunohistochemical analysis. Cells from passages 3-5 were exposed to glucose concentrations of 0.1 and 0.2% with and without insulin concentrations of 100 ng/mL and 1000 ng/mL, in the presence or absence of 200 μM of thiamine. Standard hemocytometry and 3H-thymidine incorporation quantified cell proliferation after incubation for 6 days and 24 hr, respectively. The data suggest that thiamine inhibits human infragenicular ASMC proliferation induced by high glucose and insulin. Vitamin B1 intake may prove important in delaying the atherosclerotic complications of diabetes

Chinese economic expansionism in Africa: A theoretical analysis of the environmental Kuznets Curve Hypothesis in the forest sector in Cameroon.

This paper, which is conceptually located at the intersection of trade–economics, resource politics, and environmental assessment, is a narrative-analytic review of Chinese economic expansionism in Africa especially its quest for the continent’s natural resources in the past 10 years. We seek to examine the environmental, ecological, and sociopolitical impacts of the current China–Africa engagement within the context of the Environmental Kuznets Curve (EKC) hypothesis. The EKC hypothesis posits that an inverted U-shape relationship exists between economic growth and environmental quality. This implies that the quality of a country’s environment will initially decrease due to its economic growth, but will soon start to improve when the country attains a certain threshold level of economic development/income per capita. We argue that by virtue of its ‘omission’ and/or ‘commission’ factors, the EKC hypothesis can be misleading if not dangerous. Using the case study of China’s engagement with Cameroon in the forest sector, the paper illustrates the high threshold level of economic development/income per capita that is required before the quality of the country’s environment can begin to improve. The paper ends with the environmental, ecological, and sociopolitical impacts of Chinese involvement in the Cameroonian forest sector and concludes that this engagement and the larger Chinese economic expansionism in Africa under current trading conditions is fairly detrimental to the welfare of African peoples and their environment