Comparative study between microvascular tone regulation and rheological properties of blood in patients with type 2 diabetes mellitus.

The aim of the study is to investigate the changes of the skin blood flow responses to cold stress in patients with diabetes mellitus type 2 through wavelet analysis of the peripheral skin temperature oscillations and to estimate their relationship with the blood viscosity values. The amplitudes of the skin temperature pulsations (ASTP) were monitored by "Microtest" device ("FM-Diagnostics", Russia); the whole blood viscosity and the shear stresses were measured by Contraves LS30 viscometer (Switzerland) at a steady flow in 9 healthy subjects and in 30 patients with type 2 diabetes mellitus. Power law and Herschel-Bulkley (HB) equations were applied to describe the blood rheology. Both models include consistency (k) and flow index (m), and the HB also gives the yield stress (τ0). The Spearman rank correlations between these parameters and the ASTP in the frequency ranges, corresponding to the myogenic, neurogenic and endothelial mechanisms of the microcirculation tone regulation were calculated. The ASTP values decreased when the blood viscosity increased. The correlation analysis revealed good ASTP-m (r > 0.5) and ASTP-k (r < -0.5) relationships in the endothelial range, while the ASTP-τ0 correlation was weaker (r≈-0.4). These correlations became lower for the ASTP during the cold stress. The results prompt manifestation of endothelial dysfunction in patients with type 2 diabetes.

Effects of cyanobacterial biomass on the Japanese quail.

Mortality of wild aquatic birds has recently been attributed to cyanobacterial toxins. Despite this, no experimental studies on the effects of defined doses of microcystins administered orally to birds exist. In this experiment, four groups of male Japanese quails daily ingesting 10ml of Microcystis biomass containing 0.045, 0.459, 4.605 or 46.044mug of microcystins, respectively, for 10 and 30 days, showed no mortality. Histopathological hepatic changes in birds after the biomass exposure included cloudy swelling of hepatocytes, vacuolar dystrophy, steatosis and hyperplasia of lymphatic centres. On subcellular level, shrunken nuclei of hepatocytes containing ring-like nucleoli, cristolysis within mitochondria and vacuoles with pseudomyelin structures were present. Vacuolar degeneration of the testicular germinative epithelium was found in two exposed males. Statistically significant differences in biochemical parameters were on day 10 of exposure only. They comprised increased activities of lactate dehydrogenase and a drop in blood glucose in birds receiving the highest dose of the biomass. Principal component analysis revealed a pattern of responses in biochemical parameters on day 10 that clearly separated the two greatest exposure groups from the controls and lower exposures. The results indicate that diagnosis of microcystin intoxication solely based on clinical biochemical and haematological parameters is hardly possible in birds.