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Biomedical subjects

B F Korovkin

Publications and source records attributed to B F Korovkin.

At least 19 recordsLinked to original sources
PubMed1991

[The effect of a conditioned medium from neonatal rat hepatocytes on a mixed culture of Kupffer cells and fibroblast-like liver cells].

The study was carried out on primary coculture Kupffer cells and liver fibroblasts of newborn and mature rats. At first Kupffer cells and liver fibroblasts were taken on the equal quantity. There were observed significant decrease of Kupffer cells quantity and fibroblasts death after 4-5 days in coculture. Mitotic and functional activity liver fibroblasts, adhesion of Kupffer cells were increased by the using of conditioned medium of newborn rat hepatocytes. The rise of mitotic activity of liver fibroblasts and quantity of nucleolus in their nuclei forestalls of the increase Kupffer cells size, appearing of Kupffer cells with some nuclei.

Animals↗
PubMed1990

[Determination of the concentration of fructose-2,6-bisphosphate using phosphofructokinase].

Measurement of fructose-2,6-bisphosphate (F-2,6-P2) level in biologic material is based on its ability to eliminate allosteric inhibition of phosphofructokinase (PFK) with high ATP concentrations. Effects of the buffer types and length of storage of commercial PFK from rabbit muscle, manufactured by Boehringer, on the enzyme ability to inhibit ATP and activate F-2,6-P2 were examined. The enzyme showed the highest sensitivity to ATP inhibition in tris buffer and the least one in morpholine propane sulfonic acid. If PFK is stored for a year its sensitivity to ATP inhibition and F-2,6-P2 activation essentially reduces and it becomes unfit for measurement of F-2,6-P2 concentration in biologic material.

Fructosediphosphates↗
PubMed1990

[The morphological changes in a primary culture of 3-day-old rat hepatocytes cultured over 1 week and in a model of anoxia].

A direct observation of primary cultures of 3-day-old rat hepatocytes was performed with the help of time-consuming cinematography. The process of monolayer formation has been examined. In addition, the continuous preservation of bile canaliculi was observed. A significant increase in hepatocyte mobility was marked in 6-7-day cultures. The structural analysis of cultured cells during the modelling of anoxia with substrate deficiency revealed a succession in hepatocyte and fibroblast alterations. The hepatocyte destruction was accompanied with changes in the cell form, that become rounded, and in the appearance of small formations protruding on the cell surface. The fibroblast destruction appeared after cell contracture.

Animals↗
PubMed1990

[Changes in the composition of the lysosomes in hepatocytes cultured in vitro in modelling pathological states].

The monolayer cultures of newborn rats hepatocytes were treated with substrate starvation (20 min.) anoxia accompanied with substrate starvation (1 h.), following rehabilitation (1 h.) and cooling (4 degrees C, 30 min). After the neutral red staining we have examined the alterations in lysosomes quantity and the development of phagocytosis; we also tested the hepatocytes distribution due to the amount of the second lysosomes per cell. We have shown that a short time pathological treatment caused a decrease in large lysosomes (1-3 microns) amount in significant portion of hepatocytes. There were neither increase in phagosomes amount per cell nor alterations in the quantity of cells, containing phagosomes. However a long time pathological treatment caused the increase in phagosomes and cells. We propose that initial stage of lysosomal apparatus alterations, connected with reduction of CAMP level, is accompanied by a stamping of large lysosomes.

Animals↗
PubMed1989

[Acid hydrolase activity and cyclic nucleotide contents in the rat heart during myocardial ischemia and postischemic reperfusion].

The acid phosphatase and cathepsin D activities and cAMP and cGMP levels in isolated perfused rat heart were investigated during various periods of ischaemic myocardial injury and postischaemic reperfusion. The effect of phosphodiesterase inhibitor--caffeine was also studied. Free acid hydrolases activities and cyclic nucleotide content were increased under 40 and 60 min ischemia and 20 min postischaemic reperfusion. Addition of 50 microM caffeine to perfusion solution after 30 min of ischaemia resulted in increase of cAMP level, cAMP/cGMP ratio, lysosomal bound activities of acid hydrolase and decrease of free acid hydrolase activities. The obtained results suggested that defect in cAMP synthesis might be present in lysosomal membranes labilization in cardiomyocytes injured during ischaemic conditions. Addition of such agents, as caffeine, which increased heart cAMP level, may be effective in lysosomal membranes stabilization under reversible heart ischaemia and reperfusion.

Acid Phosphatase↗
PubMed1988

[Effect of hypoxia on a primary cardiomyocyte culture].

The primary cultures of 3-day old rats heart myocytes were used for studying hypoxia. The cells were gassed for 1 or 2 hours with 100% N2 or with the mixture of 90% N2, 5% CO2, 5% O2. The cells' morphology was tested by the light microscopy. The contractility of the cells was lost after oxygen deprivation. But it was reversible when the cells were exposed to 5% O2 for an hour and then were returned to the normal conditions. Oxygen deprivation changed the cell's morphology so that vacuolization, bubbling, contracture, exfoliation of the cell membrane from the glass surface could be observed. The number of the cells with morphological alterations increased when the content of oxygen in the gas mixture was lowered and the time of gassing was prolonged. The authors assume that the primary culture of the myocardial cells is a suitable model for studying the metabolic patterns of reversible injuries caused by one hour hypoxia (5% O2).

Animals↗
PubMed1988

[Acid phosphatase activity and the state of lysosomal membranes in a primary culture of cardiomyocytes of newborn rats during hypoxia].

Acid phosphatase activity, ATP and cyclic nucleotide levels were studied in primary cardiomyocyte cultures of newborn rats under hypoxic conditions. It was shown that incubation of cardiac cells in Eagle's medium supplemented with 10% calf serum during hypoxia (5% O2, 5% CO2, 90% N2) caused an hour later a decrease in lysosomal acid phosphatase activity, whereas free enzyme activity increased. The exposure of cells in Hanks salt solution to one hour hypoxia resulted in a 3-fold decrease of ATP level and further increase in free acid phosphatase activity. It was found that cAMP and cGMP levels do not depend on the presence of hypoxia. The mechanisms involved in the regulation of lysosomal membrane state are discussed.

Acid Phosphatase↗
PubMed1979

[Peculiarities of phosphorylation of skeletal muscle troponin under some forms muscle pathologies].

Phosphorylation of rat and rabbit troponin from normal skeletal muscles and from skeletal muscles of animals under avitaminosis, denervation and hypokinesia was studied. Phosphorylation was carried out by cAMP-dependent protein kinase with [gamma-33P] as substrate. The incorporation of labelled phosphorus into troponin T of the damaged muscles was decreased as compared to normal. After preliminary dephosphorylation of troponin by alkaline phosphatase immobilized on Sepharose 4B, the ability of damaged muscle troponin for subsequent phosphorylation was also decreased as compared to the control. It may be thus assumed that there exist conformational changes of troponin under muscular system pathologies.

Alkaline Phosphatase↗
PubMed1976

[Possible participation of cyclic AMP in regulating acid hydrolase activity in muscle tissue in avitaminosis E and denervation].

In the muscles of denervated and vitamin E-deficient rabbits the level of 3', 5'-cyclic AMP proved to decrease with a simultaneous increase in the activity of cAMP phosphodiesterase. In vivo experiments showed that at the concentration of 10(-4) cAMP was capable of retarding the release of acid phosphatase from the lysosome-rich fraction obtained from the muscles of E-deficient rabbits. Thus, in muscular dystrophy elevation of acid hydrolase activity in the skeletal muscle was due to leakage of the enzymes from the lysosomes as a result of decreased lysosome membrane stability because of decreased cAMP level.

3',5'-Cyclic-AMP Phosphodiesterases↗