Serum concentrations of vitamins A and E and retinol-binding protein (RBP) were measured in 25 late adolescent and young adult patients with insulin-dependent diabetes mellitus. Their serum vitamin A levels were significantly lower than those of nondiabetic control subjects of comparable age. The serum concentrations of RBP were also significantly lower in the diabetic patients. The serum levels of vitamin A in the diabetic patients as well as in the control subjects showed a significant linear regression with serum concentrations of RBP. Unlike vitamin A, serum concentrations of vitamin E were not significantly different between the two groups of subjects. These findings suggest that the reduced serum vitamin A levels in the diabetic patients reflect reduced mobilization of vitamin A from the liver.
Results are presented on the rate of thiamin cleavage by sulphite in aqueous solutions as affected by temperature (20-70 degrees ), pH(2.5-7.0), and variation of the concentration of either thiamin (1-20mum) or sulphite (10-5000mum as sulphur dioxide). Plots of the logarithm of percentage of residual thiamin against time were found to be linear and cleavage thus was first-order with respect to thiamin. At pH5 the rate was also found to be proportional to the sulphite concentration. In the pH region 2.5-7.0 at 25 degrees the rate constant was 50m(-1)hr.(-1) at pH5.5-6.0, and decreased at higher or lower pH values. The rate of reaction increased between 20 degrees and 70 degrees , indicating a heat of activation of 13.6kcal./mole.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.