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Biomedical subjects

V A Shevchenko

Publications and source records attributed to V A Shevchenko.

At least 19 recordsLinked to original sources
PubMed2005

[Genetic effects of low-dose chronic irradiation of developing seeds of Arabidopsis thaliana Heynh].

A six-year study, starting in 1987, focused on the frequency of embryonic lethals and chlorophyll mutations that arose in developing seeds of Arabidopsis thaliana growing at sites varying in the level of radioactive contamination in the 30-km control region of the Chernobyl Atomic Power Plant. The dose rate of chronic irradiation varied from 200 microR/h to 2.4 R/h. To study the genetic effects of various levels of radioactive contamination, the frequency of mutations arising in a particular generation was determined and the irradiation dose was estimated for the given generation. The dose dependence of the mutation frequency proved to follow a power function with a power less than unity, suggesting a relatively high effect for low-dose irradiation. Possible explanations of this phenomenon are discussed.

Air Pollution, Radioactive↗
PubMed2004

[Multiyear monitoring of the ecological status of industrial zones of Moscow using a test line of Drosophila melanogaster].

For 12 years, recombination rate was assessed in Drosophila melanogaster males exposed on a thermoelectric power station (TPS) of Moscow. In 1994, experiments were also carried out on another Moscow TPS for comparison. The recombination frequency in exposed males was two- or threefold higher than in the control sample. Recombination frequencies observed in different years did not significantly differ from each other. Likewise, no significant difference was observed for the results obtained on two TPSs. A dramatic increase in recombination frequency in flies exposed on TPS was considered as an adequate response to high concentrations of effective mutagens discharged by TPS.

Animals↗
PubMed2003

[Synthesis of some thiourea derivatives and their influence on biological and genetic effects of gamma rays].

The synthesis of the new radioprotective compounds ATB (I, 2-allylthioureidobenzoic acid), PTB (II, 2-phenylthioureidobenzoic acid), A-2-PTU (III, N-allyl-N'-2-pyridylthiourea), and P-2-PTU (IV, N-phenyl-N'-2-pyridylthiourea) and their influence on biological and genetic effects of gamma rays was studied. In result of investigations it must be noted that PTB displayed radioprotective effect as a result of which more plants in M1 germination and survive in M2 of the induced mutations is increased. The cytological analysis reveals that the studied substance (PTB) decreases chromosome aberration in meristem cells of pea roots almost twice as a result of postirradiation treatment. The effect of A-2-PTU in the experiments with peas greatly depends on the dose of irradiation, i.e., on the degree of damaging of the processes of cell restoration and the possibility of their partial restoration after the treatment with the protector. The results obtained suggest that chemical compounds of N,N'-disubstituted thiourea group (A-2-PTU and P-2-PTU) exert strong radioprotective effect in the experiments with peas. This is of great importance to modern radiobiology and radiation mutagenesis and also to protect hereditary structures against radiation.

Biochemistry↗
PubMed2002

[The estimation of molecular and cytogenetic effects in mice exposed to chronic low dose gamma-radiation].

Molecular and cytogenetic parameters were estimated in male CBA/lac mice exposed to chronic low dose-rate gamma-radiation (62 cGy/year) for 40, 80, 120, 210, and 365 days. After 40 days of exposure (6.7 cGy), spleen lymphocyte susceptibility to hydrogen peroxide was shown to increase. However, beginning from the day 120 of the treatment (20.4 cGy), the opposite effect was observed. An increase in number of the DNA-protein crosslinks was recorded in spleen lymphocytes only on day 40 of the experiment. The number of DNA breaks increased significantly beginning from day 120 of the experiment, as shown by the DNA-comet method. On the day 210 of irradiation, the frequency of abnormal sperm heads in the mice significantly increased. The number of normochromatic micronucleated erythrocytes of the peripheral blood remained unchanged.

Animals↗
PubMed2000

[The results of cytogenetic survey in liquidators of the Chernobyl nuclear accident].

The article represents results of long cytogenetic survey among liquidators of Chernobyl accident. The parameters studied are frequency of unstable chromosomal aberrations and frequency of symmetrical translocations. The authors show that, in spite of long term after irradiation, average frequency of cells with dicentrics and centric fusions (unstable chromosomal aberrations) remains relatively high. Discussion includes possible use of cytogenetic methods in reconstruction of absorbed radiation doses in many years after exposure.

Chromosome Aberrations↗
PubMed2000

[Effect of chronic irradiation on the genetic structure of natural populations of Arabidopsis thaliana (L.) Heynh].

The genetic structure of Arabidopsis thaliana populations from in the Chernobyl zone of radioactive contamination was studied. The dynamics of genotypic and allele frequencies of eight polymorphic loci were described. Analysis of the results obtained and earlier data revealed selection for loci Per1 and Acp2. Sharp fluctuations of allele frequencies were observed in consecutive generations of chronically irradiated A. thaliana populations. These fluctuations led to replacement of the most frequent alleles, including those close to fixation.

Alleles↗
PubMed1997

[Recombination in Drosophila melanogaster males exposed at a thermoelectric power plant].

For four years, genetic recombination was studied in Drosophila melanogaster males kept at a thermoelectric power station (TPS) in Moscow; a TPS located in another city district was taken for comparison in 1994. It was found that, in the experimental males, recombination frequency was two- to threefold higher than in the control flies. Temporal variations in recombination frequency during four years were not statistically significant. The data obtained at the two TPSs also did not significantly differ from each other. The considerable increase of the recombination frequency in Drosophila kept at the TPS may be considered an appropriate response to exposure to effective mutagens that were abundant in the TPS discharges.

Animals↗
PubMed1993

[Results of cytogenetic screening of people employed in liquidation of accident consequences at the Chernobyl nuclear plant in 5 years].

The liquidators of Chernobyl power station accident consequences were subjected to cytogenetic examination in 5 years after the accident. The analysis included a routine method of peripheral blood lymphocyte culture. The exposed and reference groups turned out to differ in the occurrence of distorted cells and chromosomal aberrations in peripheral blood lymphocytes. The highest cytopathogenic effect was seen in those, who had been working at the station in May-June 1986. The authors suggest to form the groups at high risk on the base of cytogenetic data and subject the groups to thorough examination for various diseases including malignancies.

Adult↗
PubMed1993

[Genetic disorders in laboratory mice, exposed in the region of the Chernobyl Atomic Power Plant four years after the accident].

Mice (CBA x C57BL)F1, of both sex and males C57BL were exposed within the 10 km zone of the Chernobyl Nuclear Power Station during 14, 22 and 34 days. Genetic damages of chronic radiation in the exposed adult mice, and in the course of embryogenesis, was studied. The gonadal absorbed radiation doses of the exposed mice varied from 0.5 to 1.5 Gy. The frequencies of dominant lethal mutations, abnormal sperm heads and reciprocal translocations linearly increase with increasing absorbed radiation doses. Among 49 males exposed at the embryonal stage one male heterozygote for reciprocal translocation was revealed. In other males of this group, reciprocal translocation yield was low. No uniform dependence of genetic effects from mice genotype was revealed.

Accidents↗
PubMed1992

Genetic consequences of radioactive contamination for populations of Arabidopsis.

Populations of Arabidopsis thaliana (L.) Heynh. growing within a 30 km radius of Chernobyl and characterized by radioactive contamination levels ranging from 0.02 to 240 mR h-1 were analyzed for the frequency of embryonic lethal mutations in 1987 and 1988. Plots that retained high levels of radioactive contamination long after the initial exposure were characterized by a high frequency of mutant plants. Plots with low levels of radioactive contamination, which were significantly reduced soon after exposure, were characterized by a decrease in the initially high proportion of mutant plants. Populations of Arabidopsis exposed to insignificant radioactive contamination showed no increase in the frequency of mutant plants; mutation levels were comparable to those found in control plants.

Accidents↗
PubMed1992

The mutation frequency of Drosophila melanogaster populations living under conditions of increased background radiation due to the Chernobyl accident.

One of the problems facing the program in the wake of the Chernobyl accident is the estimation of genetic damage to plants and animals. Special attention was directed to studying the influence of radioactive pollutants at the accident site by means of an appropriate test system, using standard genetic subjects. The present study describes such investigations. Levels of persistent genetic damage in natural populations of Drosophila melanogaster found in the vicinity of the Chernobyl accident site were examined from August 1986 to September 1989. Evidence is presented which indicates a relationship between the levels of radioactive pollution resulting from the Chernobyl accident and increasing genetic damage to exposed populations. The possible reasons for the decrease of mutation frequency observed in 1988 and 1989 are also discussed. Furthermore, evidence is presented which suggests that radiosensitive Drosophila mutants may be particularly sensitive indicators of radioactive pollution.

Accidents↗
PubMed1992

Genetic disorders in mice exposed to radiation in the vicinity of the Chernobyl nuclear power station.

Induced reciprocal translocations in spermatocytes of mice, either caught or exposed at the site, were observed at all levels of radioactive contamination around the Chernobyl nuclear power station. The frequency of reciprocal translocations was relatively low and increased linearly with increasing dose rate. Among 74 male mice exposed as early embryos, four reciprocal translocation heterozygotes were found. Furthermore, an increase in embryonic mortality and frequency of abnormal sperm heads was observed after termination of exposure, but these decreased rapidly with post-exposure time.

Accidents↗
PubMed1992

The monitoring of herbaceous seeds in the 30-km zone of the Chernobyl nuclear accident.

Species of wild herbaceous plants growing over a period of 3 years under chronic irradiation resulting from the Chernobyl accident were studied. Examining the mass of 1000 seeds and their germination did not yield any significant differences between groups of seeds of the same species collected from different contaminated zones. Nor did the frequency of aberrant cells in roots of germinated seeds reveal any significant differences between zones. Seeds of Plantago lanceolata, growing in areas with higher levels of radiation, did appear to be more sensitive to additional gamma-irradiation.

Accidents↗