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Biomedical subjects

V I Iakovleva

Publications and source records attributed to V I Iakovleva.

64 records · Page 4Linked to original sources
PubMedDate not supplied

[Stability of the biocatalysts of L-aspartic acid synthesis based on immobilized Escherichia coli cells].

Experiments were carried out to investigate the process of a continuous enzymatic synthesis of L-aspartic acid from ammonium fumarate in uniform filling flow reactors. Escherichia coli (Soviet strain 85) cells immobilized in polyacrylamide gel granules reinforced by a solid carrier were used as biocatalysts. The conditions, under which a high aspartase activity of the biocatalyst and a stable hydrodynamic performance of the reactor were maintained, were determined. The main kinetic characteristics of a continuous performance of the reactor for 150 days were obtained.

Acrylic Resins↗
PubMedDate not supplied

[Hemodynamics of the lesser circulation in prolonged hypokinesia (based on data from a morphological study)].

This paper presents data on pulmonary circulation of rats during prolonged hypokinesia (30 to 165 days). It was found that the hypokinetic exposure of 30 to 60 days produced venous and, in particular, capillary plethora associated with blood redistribution and pooling in the lungs. As the exposure continued, the plethora level decreased due to the development of compensatory-adaptive reactions in the lung vessels. For instance, on hypokinetic day 90 small arteries of the muscle type developed a spasm which accelerated circulation stabilization. By hypokinetic days 120-165 pulmonary circulation returned to normal due to the further development of compensatory-adaptive mechanisms in lung vessels (tendency for hypertrophy of the media of small arteries and increase of its cross-sectional area).

Animals↗
PubMedDate not supplied

[Histological and histochemical study of the liver of rats exposed on the Cosmos-690 biosatellite].

Liver samples of 12 rats flown aboard the biosatellite Cosmos-690 and irradiated with a dose of 800 rad and of 12 rats from the synchronous experiment were examined histologically and histochemically. On the 2nd and 27th postexperimental days the following morphological changes were detected; nuclear polymorphism of hepatocytes, a significant increase in the number of binuclear cells, and lipid accumulation in central lobes. The changes were more expressed on the 2nd day. These changes were induced by prolonged irradiation in space flight and synchronous experiment: they were not detected in the untreated animals.

Animals↗
PubMedDate not supplied

[Rapid method for determining protein concentrations in the cells of microorganisms].

The method of Lowry as modified by Peterson (who had changed concentrations of reagents and added a new reagent, sodium dodecyl sulfate) has been tested. It has been shown that the modified method can be applied for rapid measurement of protein in the suspension of bacterial cells. The effect of the following compounds on the protein estimation by the modified method in bovine serum albumin has been studied: potassium chloride, potassium phosphate, sucrose, EDTA, tris, ammonium acetate, Triton X-100, tyrosine, phenol, glycerol, 2-mercaptoethanol.

Bacterial Proteins↗
PubMedDate not supplied

[Morphologic changes in the lungs of rats after a flight aboard biosatellite "Cosmos-936"].

Lungs of 20 rats flown aboard Cosmos-936 for 18.5 days and sacrificed within 5-13 hours (8 weightless and 4 centrifuged rats) and 25 days (4 weightless and 4 centrifuged rats) after recovery were studied histologically. An identical number of lung specimens were withdrawn from rats of synchronous and vivarium controls. Lungs of the flight rats did not show any pathological changes or morphological signs of prolonged congestion, thus indicating the lack of hypertension in pulmonary circulation. Lungs of the flight rats exhibited an increased leukocyte count, which was more marked in the weightless rats killed 8-13 hours postflight. The elevation in the count of neutrophilic leukocytes in the flight rats was due to peripheral neutrophilia which is a manifestation of an acute stress-reaction. An exposure of rats to artificial gravity was responsible for a lesser increase in the count of neutrophilic leukocytes.

Animals↗
PubMedDate not supplied

[Morphological effects in rats following a 22-day space flight].

A morphological examination of 27 rats flown onboard the biosatellite and sacrificed on the 1st-2nd and 26-27th postflight days demonstrated no significant changes in the structural organization of the vital organs and systems of the animal body. It was, however, found that the space exposure induced morphologically detectable changes in the musculo-skeletal system, hemo- and lymphopoiesis, hypothalamic-pituitary-adrenal system and the juxtaglomerular apparatus of the kidneys. The changes were reversible and nonspecific, and could be seen in animals exposed to ground-based hypokinetic and other stress experiments. Postflight the animals developed some reactions that were similar to those in humans. This helps to identify the morphological substrate of certain changes in the human body and to investigate their pathogenesis.

Animals↗