Biomedical subjects
Publications and source records attributed to V A Shliakhovenko.
The inhibition of polyamine synthesis by DFMO (2.7 x 10(-3) M) resulted in a decrease of proliferation rate of L and OH-1 cells. The patterns of acid-soluble nuclear proteins were studied by the SDS electrophoresis. The content of protein fraction with molecular weight 25 kD was shown to correlate with the rate of proliferation of cell cultures.
Mice bearing Ehrlich carcinoma cells received one 80 mg/kg dose of DFMO. After 20 hours the cells were extracted from the peritoneal cavity and separated by means of sedimentation of 1 g in saccharose gradient into 9 fractions depending on the mitotic cycle phase. The content of polyamines in the cells of each fraction was detected by the fluorescent method using fluorescamine. It was shown that the tumor cells during G1 phase mitotic cycle (13-15% cells blocked) and especially cells in the 1st half of S-phase (19-23% cells blocked) were most sensitive to inhibitory effect of DFMO.
It was established that difluoromethylornithine (DFMO) and methylglyoxal-bis(guanylhydrazone) blocked the mitogenic response of hepatocytes to epidermal growth factor. This effect of inhibitors, especially DFMO, has been prevented by exogenic putrescine, spermidine or spermine. But neither blocking action of inhibitors nor preventing effect of polyamines associated with changes of epidermal growth factor binding to hepatocytes.
Difluoromethylornithine (DFMO) was studied for its effect on the aminoxidase activity in the culture media during proliferation and differentiation of mouse fibroblasts. Single introduction of difluoromethylornithine into the culture medium increases the polyamine oxidase activity during 12 to 24 hours after the action. In the subsequent periods DFMO in 0.1 to 1 mM concentrations inhibits the proliferation and differentiation, but 0.01 mM concentration leads to their acceleration, which correlates with higher or lower aminoxidase activities respectively in the culture media.
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Using 3H-thymidine, 14C-orotic acid and ethidium bromide identification of the nucleic acid double-stranded structures from biological fluids and the method of hemocarboperfusion the data are obtained on the active and irreversible adsorption of nucleic acids and nucleoproteins from plasma of leukaemic patients and ascitic fluid of mice with lymphoma NK/Ly.
It has been discovered that nuclear membranes isolated from human brain tumors are capable of cyanide-sensitive oxidation of adrenaline to adrenochrome in the presence of both NAD X H and NADP X H while the process of oxidation is inhibited by superoxide dismutase. At the same time nuclear membranes isolated from the brain tissue do not oxidize adrenaline to adrenochrome in the presence of both substrates. A possible relationship between the properties of the nuclear membranes and the degree of tumor malignancy is discussed.
The characteristic of the nucleic component from the nucleoprotein complex excreted by tumour cells into ascitic fluid is presented. Using enzymes which hydrolyze nucleic acids and applying the methods of cellulose chromatography and ethidium bromide identification of the double-stranded structure of nucleic acids it is shown that the nucleic component of the excreted complex is a heterogeneous system presented by double-stranded structures which involve DNA-RNA hybrid molecules.
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By methods of analytical electrophoresis nuclear chromatin proteins of normal and leukaemic hemopoietic rat cells were studied. There were revealed 1--2 extra bands in the histones extracted from chromatin of leukaemic cells. These proteins appear to be identical to histones of H10 type. The majority of nonhistone proteins of nuclear chromatin from normal and leukaemic hemopoietic cells show similar electrophoretic characteristics, whereas there were also found components typical for chromatin of only normal or leukaemic hemopoietic cells.
Purified cell nuclei from the rat liver and hepatoma-27 cells were used to prepare nuclear membranes from which the enzyme-containing extracts of acid-soluble proteins were prepared. The protein extracts were subjected to disc-electrophoresis in 15% polyacrylamide gel using modified Reisfeld's system. It was found that ribonucleases contained in the acid-soluble proteins of the nuclear membranes of normal liver are represented as several components, and differed by their electrophoretic mobility and also by some other physical and chemical properties from crystalline bovine ribonuclease, as well as from nuclear chromatine ribonucleases.
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