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Biomedical subjects

O V Smirnova

Publications and source records attributed to O V Smirnova.

At least 91 records · Page 5Linked to original sources
PubMedDate not supplied

[Ontogeny of different life forms of plants and specific features of age and spatial structure of their populations].

Materials have been generalized that were accumulated in population-ontogenetic studies of plants and leading features of the ontogeny of plants have been noted that determine specific structural features of their populations. The described patterns allowed the authors to develop simulation models of plant population dynamics. The results of simulation are provided, and they are compared to the empirical data. Problems have been considered that concern the influence of specific features of development of different plant biomorphs on the genetic structure of populations and biocoenotic processes.

Biological Evolution↗
PubMedDate not supplied

[Comparative genome analysis of Helicobacter pylori strains].

DNA macroarrays were used to characterize 17 Helicobacter pylori strains isolated in four geographic regions of Russia (Moscow, St. Petersburg, Kazan, and Novosibirsk). Of all genes, 1272 (81%) proved to occur in all strains and to constitute a functional core of the genome, and 293 (18.7%) were strain-specific and greatly varied among the H. pylori strains. Most (71%) of the latter had unknown functions; the remainder included restriction-modification genes (3-9%), transposition genes (2-4%), and genes coding for outer membrane proteins (2-4%). The Russian H. pylori strains did not differ in genome organization or in the number and distribution of strain-specific genes from strains isolated in other countries.

Bacterial Proteins↗
PubMedDate not supplied

[Features of the formation, expression and transmission of basic genetic and androgen programs of the level of unusual estrogen-binding protein in sexually mature female rat hepatocytes under experimental conditions].

Some features of the formation, expression and inheritance of basic genetic and androgen programs of the level of unusual estrogen-binding protein (UEBP) in mature female rat hepatocytes under experimental conditions were investigated. Liver regeneration after partial (2/3) hepatectomy of mature rats was used for generation of a new population of differentiated hepatocytes. The UEBP content was determined by radioligand technique in control liver and at 2, 4, 14 days of liver regeneration and related to the total DNA content as an indicator of cell proliferative activity. It was revealed that the basic genetic program of low UEBP level of hepatocytes of ovariectomized females was fully transferred to daughter cell during cell proliferation and characterized by a temporary elevation of its expression during initial steps of liver regeneration. It was shown that the androgen program of a high UEBP level was completely and stably formed after androgen action in hepatocytes of ovariectomized females and was fully transferred to daughter cells during hepatocyte proliferation. However experimentally formed androgen program of a high UEBP level in female hepatocytes was completely revealed only during early steps of liver regeneration (the 4th day), its expression was essentially declined after regeneration process was over.

Androgens↗
PubMedDate not supplied

[The effect of estrogens on the concentration of estradiol receptors in rat uterus, kidneys and liver].

The concentration of receptors to E2 decreased in the uterine cytoplasm of rat uterus and increased in the nuclei during sexual maturation. With ageing this index in the cytoplasm and the nuclei of the uterus fell, and failed to alter during pregnancy. After ovariectomy the concentration of the receptors increased in the uterine cytoplasm, but no marked changes in the receptors occurred in the nuclei. No significant changes were revealed in the receptors to E2 in sexual maturation, pregnancy and ovariectomy in the cytoplasm and the nuclei of the kidneys and the liver. Administration to rats of E2 produced a reduction of the concentration of receptors to E2 in the cytoplasm of the uterus, kidneys and the liver and an increase in their content in the nuclei of the uterus and the liver.

Age Factors↗
PubMedDate not supplied

[Estradiol receptors in the sex organs and some other organs of male rats].

A study was made of specific binding of estradiol (E2) by cytosol and the extracts of the nuclei of the testes, the prostate, the kidneys and the liver of the sexually-mature male rats. In the cytosol of all the mentioned organs there were found macromolecules with a high affinity (Kac similar 1--4-10(9)M(-1)). Low capacity ti the hormone (Nc similar to (1--2)--minus 14 mol per 1 mg of protein) and a marked hormonal sterospecificity--only the preparations with an estrogenic activity, but not testosterone, 5alpha-dihydrotestosterone, progesterone and corticosterone competed for H-3--E2 binding. The capacity of cytosol of these organs to bind E2 apecifically was eliminated by pronase, but not by RNA-ase and DNA-ase. The mentioned properties of the E2-binding macromolecules of cytosol of the testes, the prostate, the kidneys and the liver permitted to refer them to the estrogenic protein-receptors. Specific E2-binding was also revealed in the extracts of the nuclei of these organs, but its level was extremely low.

Animals↗
PubMedDate not supplied

[Characterization of the biological properties of acid-treated chrysotile-asbestos fibers].

Boiling of chrysotile of the textile brand PRZh1-50 in concentrated hydrochloric acid for 10, 15, and 20 minutes gave rise to three chrysotile-asbestos samples. The content of MgO decreased from to 24, 19, and 9%, respectively. As compared with the baseline values, the number and force of positively charged electrical centers were less in the samples containing 24 and 19% MgO and more in the sample having 9% MgO; the negatively charged centers were present in the former two samples and absent in the third one. When the samples were intrapleurally administered to rats, their hemolytic activity, induction of active oxygen radicals, mutagenic activity (micronuclear test using murine bone marrow cells), and the frequency of mesotheliomas were less in the treated samples than in the baseline ones; but there were no differences between the treated samples. Thus, the altered physicochemical properties of the fibrillar surface of asbestos diminished its biological aggressiveness; however, increased treatment rates failed to lead to its further decrease. There was no relationship of the biological properties to the number and force of electric charges of the surface.

Acids↗
PubMedDate not supplied

[Transmission of "hormonal memory" of a unusual estrogen-binding protein during rat hepatocyte proliferation in the process of regeneration].

The content of unusual estrogen-binding protein (UEBP), the level of DNA and common protein as well as the organ mass were studied over time during regeneration of the rat liver of intact males and gonadectomized males and females. In 21 days after partial hepatectomy of males with intact testes complete restoration of the UEBP content was observed simultaneously with restoration of the DNA and protein levels and the organ mass. There was no temporary decline of the UEBP content per DNA unit at the early stages of regeneration. The UEBP content in the liver grows during regeneration with the elevation of the DNA level not only in males with intact testes but also in preliminarily castrated males. Different UEBR programs were revcaled by the 21st day of liver regeneration in preliminarily gonadectomized animals: the androgen program of the elevated UEBP content in males, and the basal genetic program of the low level of UEBP expression in females. A conclusion has been made that the hormonal memory of a high UEBP content may be transferred to a new generation of hepatocytes in the absence of androgens. It has been assumed that androgens cause the real determination of masculinization of the EUBP content in liver cells.

Adaptation, Physiological↗
PubMedDate not supplied

[The role of the hypophysis and STH in the regulation of the androgenic receptor level of the rat liver and in the realization of the sex-differentiating action of gonadal hormones].

The role of the pituitary gland was investigated in the regulation of the level of rat liver androgenic receptors (AR) and in the realization of polydifferentiating action of gonadal hormones. The level of AR in the female and male rat liver was shown not to depend directly on the presence of the pituitary gland or STH administration. The pituitary gland is not a mediator in the realization of polydifferentiating action of androgens and estrogens. STH enhances the development of a positive effect of androgens on the level of AR.

Androgens↗
PubMedDate not supplied

[Changes in the testosterone levels in the serum and androgen receptor levels in the liver during experimental burns in immature rats].

Distinct and stable decrease of testosterone content was found in blood serum of one month old rats with burns of the IIIA-IIIB degree impairing 23-25% of body surface. Concentration of androgene receptors was markedly decreased in liver cytosol of the experimental animals within 1 day and to the end of the first week after the thermic trauma. Possible mechanisms involved in impairment of androgene-dependent regulation of metabolism under conditions of thermic burns are discussed.

Aging↗
PubMedDate not supplied

[The characteristics of the sex-differentiating action of sex steroids on the androgen receptors of the rat liver].

A study was made of the specificities of polydifferentiating action of androgens (A) and estrogens (E) on the level of androgen receptors (AR) of the rat liver cytosol. Androgen receptors were shown to be detected in the neonatal period of ontogenesis, their level was progressively on the increase with the body development. Sex differences in their content were revealed in mature animals only. The AR level is a reversibly controlled, but unprogrammed sex-related sign. The effects of sex steroids are dose-related and modulated reciprocally by the action of endogenous A and E. The action of physiological doses of A and E is characterized by slow development of the effect. Correlation between the level of AR and the efficacy of A action on the content of these proteins was revealed.

Androgens↗
PubMedDate not supplied

[Role of various hormones of total metabolic action in the expression of sex differentiation of the rat liver by a specific estrogen-binding protein].

The effect of some hormones of total metabolic action on a degree of sex differentiation of the liver by a specific estrogen-binding protein (SEBP) was investigated. Insulin administration did not change the SEBP level of the male rat liver. Adrenalectomy and dexamethasone administration caused no significant changes of sex differentiation of the SEBP level in the male and female rat liver. Neither did thyroidectomy cause significant changes in the SEBP level. Dose-related T3 administration decreased reversibly the SEBP level in the liver of adult male rats. The effect of T3 on the SEBP level was preserved after castration or hypophysectomy of males. T3 administration decreased a degree of determination of a raised level of SEBP in the female rat liver by androgens. STH injections were effective mainly in hypophysectomized male rats resulting, on the one hand, in an increase in the level of SEBP and creating conditions, on the other hand, for a decrease in its level caused by estradiol. It has been concluded that thyroid hormones and STH are able to be modulators of adaptive changes of sex differences of the liver by SEBP.

Adrenal Cortex Hormones↗
PubMedDate not supplied

[Multicomponent system of specific estrogen-binding liver proteins. Some properties of a rapidly dissociating estrogen-binding liver protein from guinea pigs].

A study was made of some binding and physico-chemical properties of a special estrogen-binding protein of liver cytozol in sexually mature female and male guinea pigs following its partial purification by means of ammonium sulfate sedimentation, gelfiltration and ion-exchange chromatography. The given protein proved to bind estradiol (E2) with Ka of the 10(7) M-1 order and possessed a rather marked hormonal affinity specificity. Under unbalanced conditions its complexes with E2 were capable of rapid dissociation. Characteristics of the size of protein molecules were: molecular weight--about 60000, Stokes' radius--3.2 nm, sedimentation coefficient--4.6, friction coefficient ratio--1.18. Protein E2-binding activity was reversibly depressed in the presence of high salt concentrations, decreased in the presence of dithioerythritol and on heating at the temperature of over 50 degree C. The optimum E2 binding was observed at pH 7.3--7.7. There were no significant differences in the properties of protein from the liver of males and females. A conclusion was drawn on a close similarity between the given protein of guinea pigs and of a special estrogen-binding protein of the liver in male rats detected by the authors earlier.

Animals↗
PubMedDate not supplied

[Interaction of androgen-receptor complexes in rat liver cytosol with cellular nuclei and DNA].

A study was made of the ability of androgen-receptor complexes (ARC) of male rat liver cytosol to interact with hepatic cell nuclei and DNA in a model free-cell system and after administration of androgens to animals. In a free-cell system androgen receptors (AR) within a partially purified cytosol preparation were capable of binding strongly with hepatic cell nuclei and DNA of cellulose-conjugated cow spleen. The administration of testosterone propionate for 3 days resulted in the redistribution of liver AR between cytoplasm and nuclei during testing 1 h after the last injection. The observed regularities were unrelated to changes in AR content caused by the regulatory effect of administered androgen. Similar changes in AR content in the studied subcellular fractions were revealed 1 h after single administration of R1881 but not testosterone propionate. The revealed regularities were indicative of a possibility of AR involvement in androgenic action on the liver at the nuclear level.

Androgens↗
PubMedDate not supplied

[Demonstration of a sex differentiation in the content of androgen receptors in the liver cytosol of rats].

The paper is concerned with differential quantification of the level of androgen receptors (AR) in the liver cytosol of male and female rats as well as in the prostatic cytosol. AR affinity to synthetic androgen R1881 was shown to be similar in all investigated tissues. In male rats the AR content in the liver cytosol was 20.5 +/- 2.1 fmol per 1 mg of protein, lower (p less than 0.05) than in the prostatic cytosol (30.8 +/- 2.5 fmol per 1 mg of protein). Sex differentiation of the liver AR content with 3-fold predominance in males was determined. Gonadectomy of mature rats caused leveling down of sex differences in the liver AR content as a result of a decrease in AR concentration in castrated males and its increase in ovariectomized females. Sex differentiation of the liver AR content could be an additional factor enhancing the multiple differentiating action of androgens on the male rat liver.

Animals↗