Evaluation of the contribution of smoking to total blood polonium-210 in Saudi population.

A preliminary study of 210Po concentrations in the blood of some smokers and nonsmokers is presented in order to evaluate the contribution of smoking to total blood 210Po in Saudi population. Blood samples were collected from 30 volunteers and analyzed by high resolution alpha-spectrometry using a radiochemical technique. The technique is based on the separation of polonium from other components of the sample by wet ashing with an HNO3/H2O2 oxidizing mixture and spontaneous deposition on a silver disc under the relevant conditions for alpha-particle counting. The results indicated that a significant fraction (about 30%) of blood 210Po is related to smoking.

The effect of stress on the pharmacokinetics and pharmacodynamics of glibenclamide in diabetic rats.

Optimal management of the diabetic patient includes normalization of glucose concentration. Attainment of this goal is difficult because stress has long been shown to have a major effect on metabolic activity. The aim of this study was to assess the effect of stress on the pharmacokinetics and dynamics of glibenclamide in normal and diabetic rats. In this respect, administration of glibenclamide (1.4 mg/kg, p.o.) significantly reduced the blood glucose level estimated after an intravenous challenge dose (4 ml/kg) of 50% dextrose. Peak drug effect occurred at about 2 h in the control on diabetic group and this effect was clearly evident over a 6 h period in the diabetic group. The stressed diabetic group showed consistently higher blood glucose level at all time points than the nonstressed diabetic controls. Stress was also associated with significant reductions in glibenclamide Cp-max and AUC0-infinity and an increase in the Tmax. These results suggest that the response to glibenclamide in diabetics may be strongly modified by stress through a number of mechanisms. Changes in the bioavailability of the drug and activation of sympathetic nervous system and the hypothalamic-pituitary-adrenocortical axis are potential candidates. Further clinical and experimental studies in relevant models may, however, be needed to characterize fully and relate this effect to rational pharmacotherapy of type II diabetes.