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Biomedical subjects

V I Evsikov

Publications and source records attributed to V I Evsikov.

At least 19 recordsLinked to original sources
PubMed2001

Influence of genetic dissimilarity of mother and fetus on progesterone concentrations in pregnant mice and adaptive features of offspring.

Concentrations of progesterone in blood plasma and tissue were studied in pregnant mice of strains BALB/cLac and C57BL/6J. Both intra- and interstrain mating and embryo transplantations were used as models of homo- and heterotopic pregnancy. On day 4 of heterotopic pregnancy, plasma progesterone concentrations of females of both strains were higher than those in females of both strains undergoing homotopic pregnancy. In addition, tissue progesterone content of hybrid embryos was higher than that of purebred embryos. Adrenocortical responses to social conflict as indicators of stress resistance were studied in progeny aged 2-3 months. There was a minimal increase in plasma glucocorticoid concentrations in heterotopic transplantants after 15 min pair-matching tests and 30 min crowding compared with those of other progeny, including purebred male mice of BALB/cLac and C57BL/6J strains, homotransplantants and reciprocal hybrids. Thus, genetic dissimilarity of mother and fetuses plays an important role in progesterone provision during pregnancy and also modifies development of progeny.

Adrenal Cortex↗
PubMed1997

[Genetic-ecology monitoring of cycling populations of water voles (Arvicola terrestris L.) in the south of Western Siberia].

Long-term studies on the role of the structural and functional organization of a population in reproduction control showed that the optimum level of reproduction is maintained via a complex of ethological, physiological, and genetic mechanisms. The coat color genes have a pleiotropic effect on the reproductive capacity of females and the potential for social dominance in males. The relative reproductive success of brown water voles is greater when the population size increases, whereas dark-brown individuals gain the advantage at peaks of population size. At the peak followed by a decrease in abundance, dark brown males usually held higher social ranks in the experimental groups. The results of field and laboratory experiments showed that high-ranking males gain reproductive advantage. Changes in the genetic structure in the course of population cycle depend on relative differences in fitness demonstrated by animals of different coat color under conditions of changing population size. The fact that females actively choose their mates is important for differentiation of males with respect to their adaptive value, prevention of inbreeding, and the maintenance of heterogeneity of populations as the basis of their stability.

Animals↗
PubMed1993

Changes in aggressive behavior, thermoregulation, and endocrine responses in BALB/cLac and C57Bl/6J mice under cold exposure.

Effect of cold exposure on aggressive behavior, on the concentrations of testosterone and glucocorticoids, as well as on the oxygen consumption at different ambient temperatures, and calorigenic effect of noradrenaline have been studied in BALB/cLac and C57Bl/6J males. Under normal temperature conditions, there have been no significant interstrain differences. After cold exposure (5 weeks at 6-8 degrees C), C57Bl/6J mice exhibited more pronounced adaptive changes in thermoregulation and endocrine status (increase of glucocorticoids and decrease of testosterone concentrations were less expressed in C57Bl/6J than in BALB/cLac). At the same time, males of this strain demonstrated more intensive aggression than BALB/cLac mice. Some relations between physiological and behavioral changes caused by cold exposure are discussed.

11-Hydroxycorticosteroids↗
PubMed1978

[Role of the genetic-physiological interrelationships of mother-progeny in establishing the viability and fertility of mammals. II. The weight of the embryos of BALB, CBA and DBA strain mice developing from transplanted blastocysts].

The weights of embryos and their placentas obtained by blastocysts of CBA/LacY and DBA/2 mouse strains transfer in recipient females of BALB/c strain and also by blastocysts of BALB/c mouse strain transfer in recipient females of CBA/LacY strain were analysed on the 16th gestation day. It is shown that placental weights are determined by genotypic peculiarities of embryos, although comparative placental weights of different strain embryos could also depend on females fertility. The weight of allogenic embryos (developed from transferred blastocysts) significantly excessed the weight of singenic embryos, and most significant differences were noted in females with small number of embryos. The possibilities to solve some applied and fundamental problems of mammalian reproduction given by the method of interstrain and interbreed early stage embryos transfer are discussed.

Animals↗
PubMed1977

[Aneuploidy and polyploidy in the bone marrow cells of minks of different genotypes, ages and fertility].

An analysis of aneuploidy and polyploidy in bone marrow cells of female minks of different genotype and age has shown that in young minks with unsatisfactory reproductive characteristics, and in old females, the frequency of aneuploid and polyploid cells is significantly higher as compared to that in minks having a good reproductive capacity. The increase in aneuploidy level takes place mainly in the form of hypoploidy, and an increase of the frequency of polyploid cells is accompanied by a parellel increase of the proportion of cells with a low degree of ploidy. A correlation between frequencies of appearance of aneuploid and polyploid cells in minks is observed (r = 0.69 +/- 0.27). On the basis of original and bibliographic data, a hypothesis on a genetically determined instability of karyotype in mutant minks is argumented.

Age Factors↗
PubMedDate not supplied

[Immune system and behavioural strategies of reproduction under parasitic pressure].

Since both reproduction and immunocompetence are costly, the negative reciprocal relationships between function were found in many species. Due to reproductive immunosuppression, some fraction of seasonally breeding populations of small mammals reproduces in the first breeding season, while others reproduce in the next one. Enhancement of breeding efforts under the increased risk of mortality and the reproductive delay until recovery are the polar variants of mating behavior of parasitized individuals. However the parasite-induced changes of odor, visual or acoustic signals limit the mating success of the infected hosts. The direct influence of the immune system, regularly activated by infections, to chemicals signals can be answer to the question: why these signals are honest? Decrease in strange infection risk by kin breeding can be a satisfactory strategy of an isolated population. Nevertheless, many species follow the inbreeding avoidance strategy, where the major histocompatibility complex (MHC) genes play key role in kin recognition. The advantage of MHC heterozygosity was found at the all steps of the breeding cycle; including mating choice, fertilization, pre- and postnatal development. So, the relationships between immune system and neuroendocrine regulation of behavior give proximal explanations of the evolutionary stable strategies of breeding behavior.

Animals↗
PubMedDate not supplied

[Micronucleus and cytogenetic disorders in mouse embryos before implantation].

Studies of mice embryos of different genotypes revealed 4.1% of polyploids, 8.5% of aneuploids and 7.9% of embryos with structural chromosome aberrations. Embryos of lines BAIB and CBA were reliably different in micronuclei occurrence (9.8 and 4.6%). A relation is shown to exist between the presence of micronuclei and structural aberrations. Normalization of the embryo genotype at early stages of embryogeny might occur by means of elimination of cells with disturbances or due to the death of anomalous embryos in the period of implantation.

Aneuploidy↗