Biomedical subjects

George McHedlishvili

Publications and source records attributed to George McHedlishvili.

4 recordsLinked to original sources

PubMed2004

Basic factors determining the hemorheological disorders in the microcirculation.

Hemorheological properties and disorders are very specific in the microcirculation since blood is actually not a fluid in the capillaries and in the adjacent arterioles and venules. This is because almost half of the blood volume constitutes the red and white blood cells whose size is commensurable with the microvessels lumen. Based on perennial investigations we concluded that the advancement of blood in capillaries is primarily dependent on the "structure" of the flowing blood that determines the resistance to blood advancement in the microvessels rather than on the well-known hydrodynamic relationships characteristic for the larger blood vessels. Basing on the perennial research of the hemorheological disorders in the microvessels we succeeded to specify the principal factors determining the blood flow resistance in the microcirculation. These factors are as follows: the erythrocyte enhanced aggregability > their deformability > the local hematocrit > the blood plasma viscosity. Solution of these theoretical problems is very important for the theory and practical medicine, since the blood rheological disorders in the microcirculation play a significant role in development and outcome of such essential diseases as the cerebral and cardiac infarcts, the diabetus mellitus, arterial hypertension, tumor grow, and many others.

Capillaries↗

PubMed2004

Direct beneficial effect of insulin on blood rheological disorders in the microcirculation.

Under both the in vivo and in vitro conditions we investigated the insulin effect on the most significant factor disturbing the blood rheological disorders in the microcirculation, the red blood cell aggregability. The in vivo studies we carried out in the 42 insulin treated diabetic patients (diabetes mellitus type II), as well as conducted the in vitro investigations of the blood both of the diabetic patients (24) and of the healthy people (20) where the insulin was added to the blood ex vivo. The RBC aggregability in blood investigated with the "Georgian technique" was found significantly enhanced, by about 100 per cents in the diabetic patients. Under the in vivo conditions insulin administered intravenously decreased the RBC aggregability almost to the normal level in diabetic patients. In addition, in the in vitro studies we found that the insulin lowered significantly the RBC aggregability when it was significantly enhanced by addition of Dextran-500, as well as in the blood of patients with the ischemic brain infarcts. The decreasing effect on the RBC aggregability was observed even in the healthy control group where the RBC aggregability was in a normal range.

Adult↗

PubMed2004

Regional and systemic hemorheological disorders during feet diabetic gangrene.

We investigated the RBC aggregability in the patients with the foot diabetic gangrenes: in the venous blood samples taken from the damaged foot before its amputation, as well as from the cubital vein (the systemic circulation). The RBC aggregability was investigated with the "Georgian technique" that is sensitive and provided us with direct and quantitative data. We found that the RBC aggregability was higher by about 20%, in the blood flowing from the gangrenous tissue than in the systemic circulation. Therefore, the sources of the systemic hemorheological disorders were the primarily damaged tissues. Taking into account that the blood is uninterruptedly flowing and mixing together in the whole circulatory bed we conclude that in the systemic circulation a certain compensatory mechanism provide for a partial normalization of the blood rheological properties, since the RBC aggregability never reaches the level in the blood of the healthy people.

Blood Flow Velocity↗

PubMed2002

Local RBC aggregation disturbing blood fluidity and causing stasis in microvessels.

Experiments in rat mesenterium were carried out under conditions when both pressure gradient in the chosen microvessels and their diameters were preserved constant. All details of the hemorheological events were directly visualized and documented by usage of appropriate microscopic video techniques. Intensified RBC aggregation locally produced in individual capillaries, immediately disturbs the normal blood flow structure inside their lumina and deranges the rheological properties of blood flow in the microvessels, which slows down till a full stop. The RBC aggregates gradually grow up due to addition of new cells, which become compressed and appear homogeneous. This usually interferes with restoration of blood flow in capillaries. Further the RBC aggregates can move slowly towards veins, while the flow accelerates immediately as soon as the aggregates reach the larger venules.

Animals↗