Biomedical subjects
Publications and source records attributed to M M Seredenko.
The level of lipid peroxides, concentration of lactic acid in the blood and brain tissue homogenates were measured in rats under hypoxic hypoxia and hemorrhage. Significant correlation was found between the O2 supply-consumption ratio, the concentration of lactate and the level of lipid peroxides. It is suggested that the peroxidation process is activated by hypoxia.
Anesthetized rats breathed during 1 hr with gas mixtures containing 16 to 6 per cent of oxygen. At 6 per cent of oxygen, the hypoxia of pulmonary tissue and its processes of peroxide oxidation of lipids entails a sharp increase in elastic resistance against breathing. This is combined with insignificant disorders in tidal volume which is not compensated by an increase in the breathing rate. General mechanisms of external respiration disorders in various types of hypoxia and in stress, were revealed.
The effect of phospholipids introduced into the vascular bed in the form of liposomes, was studied in pats in conditions of breathing with hypoxic gas mixture containing 7% of oxygen in nitrogen. The liposomes were shown to improve the oxygen diffusion from the blood into tissues and from air to the blood. In the result of this, the degree of the tissue hypoxia is considerably reduced, the process of peroxide oxidation of lipids is inhibited, and the efficacy of external respiration and gas exchange is increased.
The antihypoxic and antioxidative effects of phosphatidyl choline liposomes have been studied in hypoxic hypoxia, pneumonia, and acute blood loss. It was demonstrated that the body tolerance of persisting hypoxia increased on liposome administration due to elimination of lactate-acidosis, inhibition of lipid peroxidation and higher rate of oxygen diffusion through the biological barriers. The antihypoxic properties of the vesicles are determined by their remedial effect on the key mechanisms responsible for the development of hypoxic organ damage.
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The influence of long-term (6 hours) immobilization stress on morphofunctional state of lung air-blood barrier was studied in experiments of the rats. It was shown that stress provoked the marked ultrastructural changes in the lungs, which were as follows: lung tissue oedema, pronounced thickening of lung air-blood barrier and its separate layers, edema-hemorrhagic syndrome, alveolar epithelial injury, disturbance of lung surfactant systems. Such a pathological complex may be designated as a "stress lung".
Substantiation is given to the approach to the differential prescription of helium-oxygen gas mixtures with a different oxygen concentration for relieving respiratory hypoxia which develops in the obstructive and restrictive types of ventilation abnormalities.
The effect of 3-hr hyperthermia on the oxygen body regimen parameters and lung blood oxygenation was studied in dogs. A hypoxic state was shown to develop specific by arterial and venous hypoxemia, an imbalance between arterial oxygen transport and oxygen consumption, as well as hypocapnia and acid-base disturbances.
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Phospholipids injected into the organism under an acute hypoxic hypoxia prevent development of ultrastructural disorders in the air-blood barrier of the lungs, thus averting development of the pulmonary acute hypoxic hypoxia.
The influence of hyperthermia on the ultrastructure of lung air-blood barrier (ABB) was studied in experiments on dogs. It was shown that in hyperthermia both mean arithmetic and mean harmonic thickness of ABB were increased. The lung capillary endothelial layer was the most thick ABB layer, in which severe micropinocytosis could be observed. Marked destructive changes were noted in lung alveolar epithelial ABB layer up to the appearance of cell content in alveolar space and denudation of the epithelial basal membrane.
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The changes in the pulmonary air-blood barrier (ABB), occurring under the influence of helium-oxygen gaseous mixtures containing 11, 21 and 40% O2 in helium were studied in rats of two age groups (adult animals and 2-week-old cubs). The mean arithmetic and harmonic thickness of the ABB increased and its ultrastructure changed. It is suggested that helium exerts an indirect effect on the pulmonary ABB and that this effect does not depend on the O2 concentration in a gaseous mixture or on the animals' age. The electron microscopy data have demonstrated the endothelium of lung capillaries to be the most sensitive structural component as regards the action of helium-oxygen gaseous mixtures.
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Mean arithmetic and mean harmonic thickness of the lung air-blood barrier (ABB) and its component layers were studied in rats of different age groups normally and after inspiration for 30 min of a gas mixtures of N2 and 11.2% O2 by means of the morphometric analysis of electron microphotographs. Acute hypoxic hypoxia provokes an increase in ABB thickness, more pronounced in younger age groups. The ratio of ABB layers' thickness under hypoxia varied in different age groups. The data obtained suggest age-specific features of the mechanism of arterial hypoxemia development in acute hypoxic hypoxia.