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Biomedical subjects

R A Zakharian

Publications and source records attributed to R A Zakharian.

At least 19 recordsLinked to original sources
PubMed1998

[The effect of calcium precipitate of double-stranded RNA on erythropoiesis in rats with acute anemia].

On the model of experimental acute anaemia of rats, induced by injection of phenilhydrazine, the influence of calcium precipitate of double-stranded RNA (Ca-ds-RNA), introduced during the crise of anaemia, on the process of erythron restoration, was studied. In the presence of Ca-ds-RNA the number of pro- and erythroblasts in fission increases by 1.5 times, compared with "pure" anaemia situation, and accordingly there is a marked decrease in the share of microcytes, which play an important role in the restoration of cell number, and in the erythron recovery after the crise of anaemia. Less pronounced is the influence of Ca-ds-RNA on the macrocytosis, which keeps its value in spite of the increase in the speed of development and of the number of normocytes after Ca-ds-RNA introduction. The mechanism of Ca-ds-RNA inclusion in the system, which controls the process of erythropoiesis during anaemia, is discussed. A conclusion is drawn that Ca-ds-RNA may directly affect the inductive stage of erythropoiesis, stimulating the formation of competent erythroid cells in population of stem haemopoiethic cells and their proliferation. Further development of bone marrow cells takes place according to the known programme of erythropoiesis whose variations are stimulated by the current conditions of its realization, but not by the presence of Ca-ds-RNA.

Acute Disease↗
PubMed1991

[Regulation of Ca(2+)-dsRNA for proliferation and terminal differentiation processes of human fibroblasts and HeLa cells].

Ca2+ complexes of dsRNA, poly(dA) and poly(dT) of yeast low molecular weight RNA produce a pronounced mitogenic effect on human fibroblasts at early stages of fibroblast proliferation in culture. At later stages of cell cultivation Ca(2+)-dsRNA stimulates terminal differentiation by inducing the synthesis of proteins characteristic of the postmitotic population of human fibroblasts undergoing terminal differentiation. Ca(2+)-dsRNA produces a stimulating effect on c-fos and c-jun gene transcription in fibroblasts and HeLa-S-3.

Calcium↗
PubMed1990

[The mechanism of the proaggregant action on the thrombocytes of RNA and DNA molecules].

The entrance of extracellular Ca2+ in ADP-stimulated human platelets and phospholipase A2 activity have been studied under the action of Ca precipitates DNA, RNA and dsRNA. The nucleic acids and its Ca complexes (Ca-NA) have been found to induce the aggregation of isolated human platelets by stimulation of extracellular Ca2+ entrance into the platelets and the formation of phosphatidilcholine and phosphatidilethanolamine lysoderivatives having the membranolytic effect.

Adenosine Diphosphate↗
PubMed1990

[The mechanism of the incorporation into alpha-cells of double-stranded RNA, DNA and reconstructed nucleosomes].

It is shown that the interaction of Ca precipitate of double stranded RNA, DNA, including the reconstructed in nucleosome structures DNA with L-cells plasmatic membrane surface induced the increase of cyclic AMP content, stimulates calcium ion input as well the activity of phospholipase A2, resulting in increase of the phospholipid lysoform and unsaturated fatty acid level in membrane, providing the possibility of nucleic acid biopolymer translocation into cell.

Animals↗
PubMed1986

[Effect of exogenous DNA on convulsive activity].

On the corazole model of the experimental epilepsy and epileptiform activity evoked by penicillin application to the cerebral cortex with electroencephalographic registration, it has been shown that exogenous DNAs in the most cases completely or partially inhibit convulsive activity. DNA inhibited also the pacemaker activity of the Helix RPa-1 neurons.

Animals↗
PubMed1985

[Antitumor activity of Ca-double-stranded RNA from sodium nucleinate].

Ca-dsRNA introduced in the concentration of 5 micrograms per mouse 24 hours before the MG22a mouse hepatoma transplantation causes the 70% inhibition of the hepatoma growth. The sodium nucleinate used in the considerably higher concentration had a less effect. The sodium form of dsRNA also had a less antitumour effect comparing with its calcium form. The calcium form of dsRNA proves to be relatively stable and physiologically active form of dsRNA during its parenteral administration.

Animals↗
PubMed1982

[Plasmid DNA of Salmonella derby].

S. derby K 89 isolated from sick children have been found to contain plasmids which determine the resistance of these organisms to penicillin and chloramphenicol. 3 types of plasmid DNA with molecular weights of 40. 12 and 8 megadaltons (Md) have been detected by electrophoretic analysis. The dissociation of the large plasmid (40 Md) into 3 independent replicons has been observed. The circular, covalently closed forms of the DNA cointegrate and its constituent replicons have been identified by electron microscopy. In S. derby K 89 grown in broth prepared from dried meat concentrate the loss of these plasmids is observed, and the culture thus becomes sensitive to penicillin and chloramphenicol. This suggests that dried meat concentrate contains some factor capable of eliminating the plasmids.

Chloramphenicol↗
PubMed1978

[Studies of nucleic acid metabolism in cultured chick embryo cells infected with Mycoplasma gallisepticum].

M. gallisepticum infection of cultured chick embryo cells led to a sharp reduction the rate of 3H-thymidine and 3H-uridine incorporation into DNA and RNA cells, and almost completely suppressed the transposition of uridine label from the nucleus into the cytoplasm, this pointing to the inhibition of escape of RNA synthesized de novo into the infected cells cytoplasm. As suggested, weak labeling of the cytoplasm after prolonged (about several hours) incubation of cultured cells with labeled urine could indicate infection of cell cultures with the mycoplasmae.

Animals↗