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Biomedical subjects

S N Novikova

Publications and source records attributed to S N Novikova.

26 records · Page 2Linked to original sources
PubMedDate not supplied

[Conformational characteristics and packing of endogenous lipid fractions of transcriptionally active and repressed chromatin].

The fluorescence and polarography methods are used to establish certain differences in conformation characteristics of transcriptionally active and repressed forms of rat liver chromatin. The data obtained prove the nucleo-soma ability to aggregation in the repressed chromatin and confirm a decondensed character of packing in transcriptionally active chromatin. It is supposed that these peculiarities are connected with different content of calcium and iron ions in the studied fractions of chromatin. Lipids, being the components of chromatin fractions, are packed with proteins in a form of bilayer structure. The packing character is similar in the both chromatin fractions. But microviscosity of the lipid bilayer in transcriptionally active chromatin is significantly lower than that in the repressed one and this may be one of reasons of different transcriptional activity and ability to peroxidation of the studied chromatin forms.

Animals↗
PubMedDate not supplied

[Inhibitors of protein biosynthesis and development of dyslipoproteinemia in rabbits].

Acute alimentary hypercholesterolemia, developing after a single load with cholesterol, and experimental atherosclerosis, caused by long-term loading with cholesterol, were studied in young rabbits. Olivomycin, administered simultaneously with long-term cholesterol loading, and streptomycin, injected within 3 days before cholesterol loading, were used as inhibitors. These antibiotics prevented hypercholesterolemia, hyperlipoproteinemia and atherosclerosis development. The data obtained suggest that the drugs used inhibited development of atherosclerosis via selective blockade of apoB proteins synthesis in liver and intestinal tissues of the experimental animals.

Animals↗
PubMedDate not supplied

[Functional activity of fractionated chromatin from rat liver upon a single administration of carbon tetrachloride].

Functions of rat liver cell genome were distinctly altered after a single administration of tetrachloromethane into animals. Maximal alterations in the structure-functional properties of chromatin were detected within 2 hrs after intoxication. The phenomenon was accompanied by the following shifts in the chromatin active fractions: activation of DNA- and RNA polymerases, decrease in content of this fraction, increase in the ratio protein/DNA due to elevation in the protein component with molecular mass 65 kDa detected in the nonhistone fraction of electrophoretogram. Alterations in the repressed chromatin fraction were less distinct. Many parameters of the chromatin fractions were normalized within 24 hrs after the intoxication. Peroxidation of lipids contained in chromatin occurred via NADPH-and ascorbate-dependent reactions, the rate of which was distinctly higher in the repressed chromatin fraction of liver cells from the animals intoxicated within 24 hrs. These alterations in the structure-functional properties of liver chromatin fractions, developed after a single administration of tetrachloromethane into animals, were related neither to the rate of lipid peroxidation in chromatin, stimulated by tetrachloromethane, nor to alterations in Ca2+ and Mg2+ content in nuclear fraction. cAMP-dependent phosphorylation of chromatin proteins appears to be rather responsible for chemical impairments of hepatocyte membranes stimulated by tetrachloromethane.

Animals↗
PubMedDate not supplied

[Age characteristics of lipoprotein lipase activity and cholesterol levels in various lipoprotein fractions].

In practically healthy from 20 up to 95 years old persons, independently of sex, only slight alterations in the mean content of total cholesterol were noted. However, redistribution of cholesterol occurred between various classes of lipoproteins. There was a decrease of cholesterol content in high density lipoproteins (LPHD) and an increase in cholesterol content in lipoproteins of very low and low density. A positive correlation was found between the activity of postheparin lipoprotein lipase and the content of LPHD cholesterol, thus suggesting the essential role of the hydrolysis rate of triglycerides in the lipoproteins for regulation of LPHD cholesterol content, which are atherogenic factors in atherosclerosis development.

Adolescent↗
PubMedDate not supplied

[The effect of the implantation of the human apo A-I gene on the function of the hepatocyte plasma membrane in rats].

Evidences are given that implantation of human apo A-I gene to experimental animals induces essential changes in the functional state of hepatocyte plasmatic phospholipid composition, hyperpolarization development, as well as changes in the Na, K-ATPase and adenylate cyclase activities. The presence of generalized cell reaction is evidenced from the fact than biosynthesis of summary proteins gets enhanced during the above changes.

Adenylyl Cyclases↗