Biomedical subjects
Publications and source records attributed to G Ia Levin.
It is determined that during compression and decompression of blood and blood suspension the main section plane of naturally sedimented erythrocytes assume virtually vertical position and, therefore, sedimentation rate of erythrocytes rises. Also, following compression blood density in vitro is irreversibly increased. The idea of existence of erythrocyte-bonded gas microcavities is discussed.
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The severity of burn toxemia mainly depends on the blood level of endotoxins, produced by bowel bacteria. The dynamics of endotoxemia have its supreme expression at the first day of burn injury. Enterosorption promotes significant decrease in blood concentrations of endotoxins and middle molecular mass peptides, depression of their cytological action, improvement of glycogen- and protidin-synthetizing hepatic function.
The efficacy of various modes of correcting rheological disorders (membrane-protective agents, laser irradiation, plasmapheresis was compared in hypertensive patients. In 30% of the patients, the conventional antihypertensive therapy was demonstrated to deteriorate hemorheological parameters, which was due to its atherogenic impact on the blood lipid spectrum. Essential phospholipids, laser irradiation, and plasmapheresis, which are supplemented to the multimodality therapy promote a significant improvement of hemorheological parameters, which makes it possible to recommend them for management of hypertensive patients with a stable (essential phospholipids), complicated (laser irradiation), and refractory (plasmapheresis) course.
The viscosity of blood and microrheological characteristics of erythrocytes (aggregation and disaggregation rates of erythrocytes, their deformity, mechanical resistance) were examined in patients with Stage III essential hypertension. There was a correlation between the mid-hemodynamic pressure and the erythrocyte deformity, on the one hand; and the total peripheral resistance and the erythrocyte deformity, on the other. The total peripheral resistance correlated with erythrocyte aggregation rates in patients with Stages I and II hypertension. It has been concluded that examining hemorheology in patients with hypertension is of significance and it is essential to correct rheological abnormalities.
The effect of microwave radiation with the range of 8 mm (80 mVt/cm2) on rheologic blood properties was studied on 150 random-bred rats. The animals were irradiated for 5 hours a day during 3 days. It was established that the animals developed the syndrome of elevated blood viscosity. Blood hyperviscosity was detected by rotation and ultrasound viscosimeters both under low and high shift frequencies. Hematocritic index underwent no changes in exposed rats. The study revealed that microwave-induced elevation of blood viscosity was primarily caused not by hemoconcentration but by a significant decrease in erythrocyte deformability and increase in stability of the erythrocytic aggregate. Membrane damage was assumed to be one of the causes of the changes in erythrocyte rheologic properties. That assumption was confirmed by the data on the decrease of erythrocyte mechanical resistance following the exposure to microwave radiation.
In experimental investigations on the rats, it was revealed that burn shock was followed by lesion of the renal tubules and glomerules, appearance in the urine of the high- and low-molecular proteins. Therapy of acute renal failure with heparin, trental and troxevasin prevents glomerular and tubular disorders. The authors consider that acute renal failure is associated mainly with hemodynamic disorders in the kidneys.
Altogether 118 patients with stages I-III essential hypertension were examined for hemodynamics and rheologic blood properties: total viscosity, deformability, aggregation, form and mechanical resistance of red blood cells, plasma osmolality, hematocrit, and red blood cell count. The data obtained indicate that in patients suffering from essential hypertension, there occur consistent abnormalities of hemorheology, correlating with the disease stage and some hemodynamic parameters. Early changes in red blood cell deformability and their discospheric transformation turned out to be the most specific in patients with essential hypertension. Red blood cell aggregation and hydrodynamic deaggregation underwent alterations mainly in complicated disease patterns.
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Rheologic parameters of the blood were examined in 17 patients with necrobiosis lipoidica before and over the course of trental (pentoxyphyllin) therapy. The study has revealed an unchanged hematocrit in the presence of significantly increased blood viscosity, red cell aggregation and stability of red cell aggregates. Another finding was a deterioration of the red cell deformability; red cell mechanical resistance was found liable to alter. Trental therapy has resulted in positive shifts in respect of the skin symptoms; a tendency to normalization of the examined blood rheologic parameters was observed in all the patients.
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Microcirculatory and rheologic disorders associated with neurocirculatory dystonia, essential hypertension and coronary disease are reported. The pathogenetic role of microcirculatory and rheologic disorders in cardiovascular diseases is outlined. The value of erythrocyte deformability for rheologic disorders is established. The efficiency of Trental treatment for coronary disease is demonstrated.
A study was made of the possibility of inducing red cell aggregation with the substances that change the shape of the cells. It was established that crenate agents stimulate red cell aggregation and substantially increase the viscosity of their suspension. A distinct correlation was shown to exist between the changes in the red cell shape and intensity of changes in the rheological properties. It was found that the recovery of the red cell shape altered by crenate agents to the discoid one effected with the aid of chlorpromazine diminishes the aggregation of blood cells as well. Basing on the studies a hypothesis is advanced of the determining role of changes in the cell shape in the mechanism by which the cells aggregate. This hypothesis enables a new approach to the problem of intercellular interactions.
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