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L I Stepanova

Publications and source records attributed to L I Stepanova.

16 recordsLinked to original sources
PubMed1990

[An evaluation in the Ames test of the mutagenicity of the sewage and industrial effluents from the Baikal Paper and Pulp Combine].

The use of the Ames test for the analysis of industrial effluents from cellulose production and sewage waters varying in the degree of purification with the aid of a metabolic activation system from rat and fish liver with Salmonella strains TA 98 and TA 100 revealed a strong direct mutagenic effect of strain TA 100 in samples after cellulose chlorination. The multistage procedure of sewage water purification allows to remove practically completely the mutagenic substances. A simultaneous study of cytotoxic effects of industrial effluents on mammalian cells shows that the mutagenic activity is exhibited in not toxic concentrations. The urgency of a regular biological control over the genotoxicity of industrial effluents from the sulfate production of cellulose is under discussion.

Animals↗
PubMed1987

[Induction of the monooxygenase activity in fish tissues by polycyclic aromatic hydrocarbons and its use in the biomonitoring of water pollution].

Monooxygenase activity changes in the liver and in other tissues of certain fish species were studied after injection of methylcholanthrene and aminoanthracene to fish. Determinations of the benz(a)pyrene hydroxylase activity and activity of 7-ethoxycoumarine 0-dealkylation in the monooxygenase system were proposed as test-systems for the control of polycyclic hydrocarbon contents in natural and waste waters. The metabolic activation (Aim's test) performed by the liver microsomal fractions of different fish species was used for the analysis of sulfate cellulose industry waste waters.

Animals↗
PubMed1986

[Ecological and toxicological control over the status of the environment by the methods of physicochemical biology].

Xenobiotic metabolism in the fish liver has been investigated with a view of developing test-system for biomonitoring based on multienzyme membrane-bound complexes. Extraction methods of xenobiotics from harmful pollutants and some biological tissue have been described using various sorbents and solvents. The own and literary data on the study of mutagenic effect of this contaminants and carcinogens in the Ames test-system in the presence of postmitochondrial fraction S9 from fish liver with 3-methylcholanthrene induced by microsomal oxidation system have been demonstrated.

Animals↗
PubMed1985

[Test systems for biomonitoring based on membrane-bound enzyme complexes. V. Mixed-function monooxygenase induction in the liver microsomes of Lake Baikal fish].

The content of cytochrome P450 and monooxygenase activity has been studied in the liver of Baikal fishes (Coregonus automnalis, Thymallus articus, Brachymystax lenok and Cottocomphorus greminsky). The administration of 3-methylcholanthrene increases considerably the level of metabolic activity of microsomal fraction and cytochrome P450 content in liver. The data of microsomal fractions of rats and fishes liver electrophoresis have shown that xenobiotic causes the synthesis of similar according to the molecular weight forms of cytochrome P450 in these animals. The induction of microsomal monooxygenase inhibits the lipid peroxidation of microsomal fraction.

Animals↗
PubMed1981

[Combined effect of an Ehrlich ascites tumor growth-inhibiting extract and adrenaline on cell division by that tumor in vitro].

It has been shown that both Ehrlich's ascites carcinoma (EAC) growth inhibition extract and adrenaline exert a pronounced inhibitory effect on cell division of this carcinoma in vitro. As a result of administering the extract in doses of 0.5 and 1 ml/per sample this effect lasted one and two hours, respectively, while with adrenaline (2.5 micrograms/ml) this effect lasted three hours with subsequent normalization of the mitotic index. Addition of adrenaline to the samples containing the extract was followed by the enhancement and prolongation of the inhibitory effect: at doses of the extract 0.5 and 1 ml the inhibition persisted 2 and 4 hours, respectively. The action of the extract with adrenaline was reversible. The data obtained indicate that despite the fact that mitosis-inhibiting activity of the EAC cell extract may be manifest in the absence of adrenaline, the latter affects the pattern of the extract action.

Animals↗
PubMed1975

Diurnal rhythms of cell reproduction and of some morphometric indices in the thyroid gland of young rats.

Monophasic diurnal rhythms of mitosis and DNA synthesis are characteristic of the thyroid gland epithelium of young rats (unlike adults). It is postulated that the diurnal rhythm of mitotic activity is under the influence of a mechanism synchronizing the cell population before mitosis. With an increase in thyrocyte differentiation the number of mitoses and of DNA-synthesizing cells falls. Diurnal changes in the duration of mitosis affect the dynamics of the diurnal rhythm of mitotic activity. Changes in the height of the follicular cells during the 24-hour period are evidence of a diurnal rhythm of thyroid function in young rats.

Animals↗
PubMedDate not supplied

[Membrane lipids of brush border of the rat small intestine as affected by ionizing radiation].

It was established that single total X-ray irradiation in the doses of 0.1; 0.4; 1.0; 2.0; 3.0 and 6.0 Gy 24 hours after irradiation results in reliable changes in membrane lipids composition of brush border of enterocytes in doses over 1.0 Gy. By this changes under increase of dosage of irradiation it were marked differences in comparison with control in lipid-protein, total phospholipids-protein, cholesterol-protein and cholesterol-total phospholipids rations. In lipid composition major changes are connected with increase of lysophosphatidylcholine and lysophosphatidylethanolamine concentrations, decrease of sphingomyelin content and increase of that of phosphatidylethanolamine. Content of cholesterol and free fatty acids decreased reliably under irradiation in doses over 1.0 Gy as well. Data obtained proves that structural-functional properties of brush border membranes of enterocytes of small intestine are altered under irradiation in doses ranging from 1.0 to 6.0 Gy. Lower doses (0.1; 0.4) cause only trend of changes named above.

Animals↗
PubMedDate not supplied

[State of the temporal organization of the system of cell reproduction in rat tissues under hypokinesia].

The study of time parameters of cell kinetics in the rats exposed to 34-day hypokinesia showed that changes in cell reproduction developed in rapidly and slowly renovating cells in a different way. The DNA synthesis and mitotic division were drastically inhibited in liver cells; the duration of the premitotic period of the mitotic cycle was significantly reduced in the cryptal epithelium of the small intestine. Hypokinesia did not cause important changes in the phasic structure of diurnal rhythms of cell division in the tissues tested and, consequently, did not lead to changes in the mechanisms of time organization of the cell reproduction system. It is concluded that the state of motor activity of animals is not the major time cue for cell division processes.

Animals↗
PubMedDate not supplied

[Enzyme activity in rat intestines after exposure to x-irradiation].

It is established that 24 hours after total X-ray irradiation by doses of 0.5, 1 and 2 Gy activity of intestine enzymes (saccharose and alpha-amylase) increases. A dose of 3 and above induces an increase of saccharose activity and inhibition of alpha-amylase. The functional state of basic phosphatase under action of the doses investigated remains practically unchanged.

Alkaline Phosphatase↗
PubMedDate not supplied

[The comparative characteristics of the transmembrane ionic currents and the caffeine-induced responses of the smooth-muscle cells in the normal jejunum and under ionizing radiation exposure].

A comparative investigation of transmembrane ion currents and caffeine-induced responses of single smooth muscle cells isolated from the circular layer of rat small intestine was carried out by the method of "patch-clamp". No reliable difference in potential-dependent and amplitude-kinetic characteristics of transmembrane ion currents in cells of intact and irradiated with dose of 3 Gy rats was revealed. In cells of irradiated animals external application of caffeine (4 mM) was not accompanied by strong quick-inactivated transient Ca(2+)-dependent potassium current as in control. The results obtained suggest that single whole-body X-ray irradiation with dose of 3 Gy does not lead in 5 days to any reliable alteration of potential-controlled channels of rat small intestine smooth muscle cell plasma membranes causing at the same time the disturbance of Ca-binding function of intracellular pools.

Animals↗