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Biomedical subjects

E A Kovalenko

Publications and source records attributed to E A Kovalenko.

At least 37 records · Page 2Linked to original sources
PubMedDate not supplied

[Effect of prolonged hypokinesia on PO2 dynamics in the brain tissues of rats in orthostatic and antiorthostatic tests].

Variations of PO2 in rat brain tissues were assessed polarographically during orthostatic tests. Prolonged hypokinesia (up to 100 days) did not induce significant changes of PO2 in rats at rest. During orthostatic tests PO2 of control rats changed insignificantly. Prolonged hypokinesia led to more marked changes of PO2 in rats exposed to an orthostatic test. Changes in the cerebral oxygenation of hypokinetic rats were varying and inadequate, differing appreciably from the cerebral oxygenation of control animals.

Animals↗
PubMedDate not supplied

[The molecular-weight characteristics of the bacterial lectins and humus components in soil].

A method has been developed to determine the molecular-weight distribution of biologically active substances: bacterial lectins and soil humus compounds. The method based on the simultaneous centrifugation of samples and molecular weight standards in the density gradient of NaCl solutions or combined gradient of NaCl and CsCl solutions permits analysing biologically active substances: lectins, proteins, polysaccharides, protein-polysaccharide complexes, humus compounds in the interval of molecular weight of 13.7 kappa [symbol: see text] a to 2000 kappa [symbol: see text] a. The use of this method in the soil researches makes it possible to study the dynamics of change of molecular parameters of the soil organic matter depending on agrotechnical methods as well as to determine transformation regularities of microbial polysaccharides.

Bacillus subtilis↗
PubMedDate not supplied

[Physical work capacity and oxygen requirements of rats during physical exertion following prolonged hypokinesia].

The white rats exposed to 60 and 100 day hypokinesia showed a substantial and progressive decline in the tolerance to a maximum physical load. This was accompanied by disorders in the regulation of the oxygen balance: during load oxygen requirements were mainly met by the oxygen debt. The above changes that followed a 100 day hypokinesia returned to the normal two months later.

Adaptation, Physiological↗
PubMedDate not supplied

[Search for lectin producers among some yeast species].

Hemagglutinating properties of culture liquid and cells of 142 yeast strains of species Saccharomyces cerevisiae, Kluyveromyces marxianus, K. dobzhanskii, K. lactis var. lactis and K. lactis var. drosophilarum, isolated from various sources have been studied. A capacity of yeast (44% of the studied strains) to synthesize both lectins bound to a cell and extracellular lectins has been established; the latter have been found in yeast for the first time.

Culture Media↗
PubMedDate not supplied

[Search for lectin producers among the yeast of Pichia Hansen emend. Kurtzman genus].

Strains (103) of yeast from Pichia genus: P. anomala, P. guilliermondii and P. membranaefaciens species have been investigated. The researchers have found 87 strains (84.5%) capable to form extracellular and surface lectins with activity to 512 hemagglutinating units. The overwhelming number of strains (75.7-92.6%) synthesized lectins of the both forms. Considerably less quantity of lectin producers of some form--extracellular or surface ones--have been found. Availability of producers of extracellular lectins was characteristic to greater extent of the yeast of P. anomala and P. guilliermondii, and producers of surface lectins--mainly of P. guilliermondii. The most active producers of lectins have been isolated from human and animal organisms, soils and wine.

Hemagglutination Tests↗
PubMedDate not supplied

[Lectin activity of antitumor substances synthesized by Bacillus subtilis B-7025].

Nutrient medium, which is optimal for synthesis of biologically active substances and allows obtaining stable outflow of Bacillus subtilis B-7025 to the culture medium, has been selected under the conditions of the bacillus periodic cultivation. It has been established that these substances are extracellular lectins with high activity and carbohydrate specificity to fructose-1.6-di phosphate, N-acetylneuraminic acid and glucose derivatives: D-glucuronic acid and D-glucosamine.

Antineoplastic Agents↗
PubMedDate not supplied

[Patterns in the change in the body state of dogs during a breakdown of the atmosphere regeneration system in a pressurized space].

Experiments were carried out on dogs kept in a sealed chamber. Changes in the O2 and CO2 concentrations as well as variations of physiological functions, the so-called survival curves, were studied under the conditions of terminated O2 supply and CO2 utilization. The criteria of investigation, mathematical and physiological analysis were chosen from the point of view of predicting hazardous states during failures of the environmental control system. Tolerance limits during slow and rapid changes of the environment, phases of changes of the body state and mechanisms of a combined effect of increasing hypercapnia and hypoxia were considered.

Air Conditioning↗