Biomedical subjects
Publications and source records attributed to T V Shimanskaia.
Disorders of myocardial pumping function were shown in experimental dogs under hyperthermia. End-systolic, end-diastolic and stroke volume were decreased under those conditions. The effectiveness of Frank-Starling mechanism was reduced in severe hyperthermia.
Breaking of myocardial pumping function was shown in experiments in anesthesized dogs under hyperthermia. The end-systolic, end-diastolic and stroke volume was decreased under those conditions. The effectiveness of Frank-Starling mechanism was reduced in severe hyperthermia.
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A substance inhibiting DNA synthesis in mouse leukemic cells was isolated from the regenerating calf spleen. When added to a suspension of leukaemic cells, this substance is adsorbed on their surface. The following changes in cell features being noticed: 1) a minute decrease in electrophoretic cell motility, 2) a decrease in esterase activity of the cells, 3) an increase in microviscosity of membrane lipids, 4) an increase in the intracellular pH values. With a longer contact with this substance, changes in nuclear chromatin structure were noticed, with special reference to weakened bonds between DNA and proteins. The data obtained are of significance for revealing molecular mechanisms of hematopoietic mediator action on target cells.
The leukemic mice treated with cyclophosphamide were injected twice a week with the allogenic splenocytes treated for 4 h with the substance isolated from the calf spleen. The leukemia growth inhibition was observed. Syngenic splenocytes were inactive. Allogenic but not syngenic splenocytes manifested a certain antileukemic activity observed in the Winn neutralization and 51Cr release tests, however this activity did not correlate quantitatively with more pronounced antileukemic action of cells in vivo.
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When leukemic cells in vitro are treated with the substance isolated from the regenerating calf spleen, incorporation of 3H-thymidine into DNA is rapidly inhibited. The completeness of DNA synthesis restoration after washing off cells from the substance depends on the duration of the previous contact with the substance. It is the change in the structural organization of chromatin but not the very fact of inhibition of the ability of the cells to the DNA synthesis that is important for a decrease of transplantability of mice cells treated by the substance. The quicker the stability of the DNA/protein interaction in chromatin weakens due to the effect of the substance, the earlier the leukosogenic potential of the treated cells decreases.
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Preparations of RNA and histones change the electrophoretic mobility of lymphoid cells, the intensity of their respiration and anaerobic glycolysis, and thermo-merchanical properties of DNA-complexes isolated from lymphoid cells. RNA and histones exert their influence on the properties of DNP-systems and the rate of anaerobic glycolysis in the opposite manner. But both these preparations depress the electrophoretic mobility and oxygen consumption.
Nucleoprotein-celite chromatography of cultivated cells nuclei, where incorporation of 3H-thymidine, 3H-UTP and 14C-aminohydrolysate into the cells was studied, enabled to detect that lowering of DNA-protein interactions in intact cells occurred simultaneously with a decrease in the rate of spontaneous macromolecular synthesis. The natural growth-regulating drugs, which inhibited distinctly DNA synthesis, inhibited RNA synthesis only slightly and stimulated protein synthesis within the first hours of the cells cultivation, prevented a decrease in tightness of DNA-protein bonds at the beginning of cultivation and then contributed to the reaction thus correlating with inhibition of RNA and protein synthesis. Definite interrelationship was found between alterations in the chromatin structural state and the cells functional activity. The cells lost their functional activity after pronounced decrease in tightness of DNA-protein bonds.
The effect of severe hyperthermia on the circulatory function was studied in dogs. Arterial pressure was maintained at the normal level, cardiac output increased at the core temperature of about 40 degrees C. An abrupt fall of the arterial pressure and cardiac output was observed at the rectal temperature of about 41 degrees C. The results suggest that a decrease in the cardiac output during severe hyperthermia is due to the fall of the central venous pressure and to the increase of the vascular compliance.
Leukemic cells administered to X-irradiated mice modify the radiobiological effect to a degree that depends on the radiation dose, bone marrow transplantation, the quantity and quality of leukemic cells, and the time of their administration.
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DNA synthesis intensity and spectral and fluorescent properties of leucemic, PHA-induced and intact normal mouse spleen cells and of nuclei isolated from these cells were investigated. The cell electrophoretic mobility and DNA-protein interaction in the nuclei were studied. Similarity in cell and nuclei fluorescence, fluorescence of the probe ANS conjugated with the cells, the electrophoretic mobility and tightness of DNA--protein interaction for leucemic and PHA--induced cells and also the similarity of the tightness of DNA--protein interaction for leucemic and normal intact cells were found inspite of the differences in DNA synthesis intensity and cell functional peculiarities.
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Activities of DNAase I, DNAase II, RNAase I and RNAase II were altered in lymphoid tissue during development of lymphoid leukosis in mice of AKR strain, during survival of the leukemic cells as well as in leukemic spleen tissue of mice C57BI with transplantable leukosis La. The enzymatic activity correlated with the step of the process, the rate of leukemic cells proliferation, with dimensions of organs. Variations in the enzymatic activity, as compared with normal state were dissimilar in development of leukosis; activity of the enzymes was either increased or decreased apparently due to their multiple functions in metabolism of nucleic acids.