[Allelic variants of polymorphic genes associated with a higher frequency of chromosome aberrations].

Genotypic associations were studied for the frequency of chromosome aberrations in human peripheral blood lymphocytes. Cytogenetic analysis (1000 metaphase plate per individual) and genotyping at 19 sites of genes involved in detoxification and DNA repair were performed in a sample of 83 Chernobyl liquidators and a matched control sample of 96 volunteers. In either sample, the frequency of chromosome aberrations was higher in carriers of the minor alleles of the XPD gene (sites 2251T > G and 862G > A) and the positive genotypes of the GSTM1-GSTT1 genes. The highest frequency of chromosome aberrations was observed in carriers of a combined genotype including at least one minor allele of the XPD sites + at least one insertion in the GSTM1-GSTT1 genes. The high-risk genotype, which had a prevalence of 64%, was strongly associated with a higher frequency of chromosome aberrations in both volunteers (OR = 6.9, P = 0.008) and Chernobyl liquidators (OR = 5.6, P = 0.002).

[The relationship between genotypes and frequencies of chromosome aberrations in human lymphocytes under irradiation in vivo and in vitro].

The data on the variability of an elevated level of the frequencies of chromosome aberrations for a group of liquidators of the Chernobyl Nuclear Station accident depending on genotypes by candidate loci are presented. The genotyping was carried out by sites, which previously showed the associations with the cytogenetic variability in control experiments. It was shown that, for a group of liquidators heterozygote by site SOD2 C47T, the control level of the frequency of chromosome aberrations is not exceeded significantly. At the tendency level, the frequency of aberrations for liquidators was reduced for double homozygotes by deletions of genes GSTM1-GSTT1 and for homozygotes by the minor allele of site CYP1A1 T606G that is in an accordance with the results of experiments with the control sampling. The elevated level of chromosome aberrations for liquidators, as a whole, is observed for genotypes, which are characteristic of an elevated level of spontaneous aberrations, and it does not completely correspond to genotypes with the elevated radiosensitivity of chromosomes.

[Polymorphism of repair genes and cytogenetic radiation effects].

For 99 healthy volunteers, the frequencies of spontaneous and y-induced (1 Gy in vitro) chromosome aberrations in blood lymphocytes were compared with the results of PCR-genotyping by 8 repair genes: XRCC1, XPD, ERCC1, APEXI, RAD23B, OGG1, ATM, Tp53 (in all, 10 polymorphic sites). The frequency of spontaneous aberrations of chromosome type increased additively with the number of copies of minor allele of excision repair gene XPD variant *2251G and *862A D (p = 0.025). The frequency of gamma-induced chromosome aberrations proved to be elevated for the carriers of a minor allele OGG1*977G (p = 0.011). The significantly elevated number of gamma-induced chromosome aberrations was also observed for the carriers of major alleles XRCC1*G1996 and XRCC1*C589 (p = 0.002).

[Somatic mutagenesis in human lymphocytes depending on genotypes for detoxification and oxidative response loci].

Associations of polymorphism of seven detoxification genes and three genes of oxidative response with the frequency of chromosome aberrations in human peripheral blood lymphocytes were studied. The genotyping data were correlated with the frequencies of spontaneous and gamma-induced (1 Gy in vitro) chromosome aberrations estimated for a group of healthy donors (97 males under 25 years of age) by analyzing 500-1000 metaphase cells per individual. The spontaneous level of aberrations of the chromosomal type was reduced in homozygotes for the GSTM1 locus deletion, and especially in double homozygotes for deletions of the GSTM1 and GSTT1 genes. The frequency of gamma-induced chromosome aberrations was reduced in G/G homozygotes for the minor allele of the poorly studied CYP1A1 T606G site: 0.094 +/- 0.006 against 0.112 +/- 0.002 for T allele carriers (P = 0.004). Linkage of the T606G site with well known and functionally important sites of the CYP1A1 gene (A4889G, T3801C) was analyzed.

[The effect of polymorphism of genes of xenobiotics detoxication on the frequencies of spontaneous and induced chromosome aberrations in human lymphocytes].

Here presented the data on the frequencies of chromosome aberrations in lymphocytes of peripheral blood of 97 volunteers depending on genotypes by genes of xenobiotics detoxication before and after gamma-irradiation with dose of 1 Gy in vitro. The frequencies of aberrations were estimated by analyzing not less than 500-1000 metaphases per person. The data of cytogenetic analysis were compared with the results of PCR-genotyping of loci GSTM1, GSTT1, GSTP1, CYP1A1, CYP2D6, NAT2, and MTHFR. The significant differences by the frequencies of aberrations between "single-locus" genotypes were not found except for GSTM1 locus, for which the enhanced frequency of spontaneous aberrations of chromosome type in "positive" genotypes compared to "zero" ones, i.e., homozygotes by deletion (p = 0.04) was observed. The minimum frequency of spontaneous aberrations of chromosome type was recorded for carriers of double homozygotes by deletion of GSTM1-GSTT1: 0.0006 +/- 0.0003 against 0.0027 +/- 0.0003 for the rest of genotypes (p = 0.016 by the Mann-Witney test). The frequency of gamma-induced chromosome aberrations was correlated with the total amount of minor alleles in loci GSTP1, NAT2, and MTHFR (r = 0.25 at p = 0.0065).

[Genotype dependence of cytogenetic and epidemiological characteristics in the liquidators of the accident at the ChNPP].

The dependence of the level of unstable chromosome aberrations and nononcological diseases on the genotype in 57 liquidators of the ChNPP accident was studied. Candidate genes presumably affecting radiosensitivity were highly polymorphic loci of xenobiotic detoxication genes (glutathione-S-transferases GSTM1, GSTT1, GSTP1) and the 5,10-methylenetetrahydrofolate reductase gene (MTHFR) involved in DNA methylation and synthesis. An increased frequency (0.014 +/- 0.001 per cell) of unstable chromosome aberrations, including radiation-specific dicentrics and centric rings (0.0015 +/- 0.0002 per cell), has been found to be preserved in the group of liquidators examined in 2006-2007. No associations of polymorphism for each of the studied genes with cytogenetic parameters were revealed. Increased frequencies of chromosome aberrations were recorded in homozygous carriers of a deletion at the GSTM1 locus in combination with homozygosity for minor alleles at the MTHFR and GSTP1 loci (p = 0.00002 and p = 0.0233, respectively). The number of homozygous carriers of the minor allele GSTP1 was increased among patients with chronic obstructive pulmonary disease and in liquidators with acute circulation disturbances (p = 0.014 and p = 0.04, respectively). Double homozygotes for GSTM1 and GSTT1 deletions were significantly more frequent among subjects with benign tumors (cysts, polyps, p = 0.015) and with benign thyroid tumors (p = 0.017). This genotype has proved to be protective for patients with severe cardiovascular diseases (acute circulation disturbances, p = 0.027).

[Genetic polymorphism of glutathione-S-transferases and inhibition of DNA repair].

A complex investigation of different cell defence systems, such as: DNA repair, antioxidant system (SOD), xenobiotic detoxification system (glutathione-S-transferases M1 and T1), radioadaptive response (RAR) in lymphocytes of patients with hereditary disease of connective tissue (Elers-Danlose syndrome) was carried out. The frequency of genotype GSTM1 (0/0) in children with Elers-Danlose syndrome (23%) is lower as compared to the control group (44%). The lymphocytes of children with Elers-Danlose syndrome were characterized by reduced ability to repair gamma-induced damage of DNA. At given size of the samples of examined children no correlative relationships between GST-status of organism and the condition of other cell defence systems were revealed. The data obtained demonstrate the individual peculiarities of the defence systems in repair-deficient cells of the examined children.

[The theory and practice of constructing calibration curves in biodozimetry].

The methodical peculiarities of experimental construction of regression "dose-effect" relationships used for the dose reconstruction are discussed. The method of computer simulations is applied to study the efficiency of different statistical procedures for plotting regression curves as well as the dependence of errors in dose prediction on the volume of examined material and on the choice of doses for a calibration curve. The causes of essential variability of calibrations obtained by different teams of researchers are discussed. A number of methodical recommendations is given for statistical processing of cytogenetic data. The procedure of constructing calibration dose dependence of the frequency of dicentrics on the basis experiments with in vitro gamma-irradiation of lymphocytes from blood samples of 5 donors is considered in detail. The expressions for statistical errors occurring in the dose reconstruction made on the base of the frequency of aberrations were derived and checked by the computer experiment.

[The problem of the transgeneration phenomenon of genome instability in sick children of different age groups after the accident at the Chernobyl Nuclear Power Plant].

A complex genetic examination of children which belong to two cohorts and their parents were carried out. The first cohort included children and constantly living on territories contaminated with radionuclides (Novozybkov district, Bryansk region). They were subdivided in groups according to the ontogenetic age periods of development of their parents at the time of the Chernobyl accident. In the children born in 1986-1995 the level of aberrant genomes is significantly higher as compared to the control (p < 0.001). In children born in 1998-2002 the differences are insignificant (p > 0.05). The frequency of aberrant genomes had a tendency to decrease with the period of time between the birth date of a child and the moment of the accident. Analysis of the results of cytogenetic investigation for the same living on territories with different densities of radioactive contamination (zone I-- 627-688 kBq/m2, 137Cs and zone II-- 135-402 kBq/m2, 137Cs) revealed insignificant differences in the spectrum and average frequencies of chromosome aberrations. The second cohort included children born in 1987-1991 and 1993-2002 from irradiated fathers (Chernobyl clean-up workers) and unirradiated mothers living on territories without radionuclide contamination. These children also displayed increased frequencies of aberrant genomes as compared to the control (p < 0.001). The analysis of the dynamics years of birth of cytogenetic disturbances in the same cohorts of children showed the average frequencies of aberrant genomes remain higher than the control level. In most of the children of both cohorts the repair synthesis of genome DNA by gamma- and UV-radiation is reduced as compared to one in the children from the control group.

[Cytogenetic effects in plant populations from the East Urals Radioactive Track]. / Tsitogeneticheskie éffekty v populiatsiiakh rastenii, proizrastaiushchikh na Vostochno-Ural'skom radioaktivnom slede.

Mutation dynamics in generations was studied in natural populations of plants from the East Ural Radioactive Track (EURT, Kyshtym accident). The experiments were aimed at the investigation of the formation of genetic load in natural plant populations under conditions of prolonged radiation exposure. The main approach used in the study was the analysis of cytogenetic alteration, chlorophyll and gene mutations in plants exposed for more than 40 years to chronic beta-irradiation and in their progeny.

[Isolation and identification of the smallpox virus which caused iatrogenic vaccinia in children in the city of Vladivostok]. / Vydelenie i identifikatsiia virusa ospovaktsiny, vyzvavshego iatrogennuiu vaktsiniiu u detei v g. Vladivostoke.

The comparative study of the specimens of the morphological elements of exanthema obtained from 8 children with the clinical diagnosis of secondary exogenic vaccinia, dried smallpox vaccine and the cultures of other orthopoxviruses (rabbit pox, monkey pox and buffalo pox viruses) was made. The isolation and identification of the causative agents from the specimens was carried out with the use of modern virological, electron microscopic and molecular methods. The study proved the fact that 8 children had orthopoxvirus infection with its causative agent identified as vaccinia virus.

[The identification of alphaviruses by using cDNA probes complementary to the 3'-terminal of the viral genome]. / Identifikatsiia al'favirusov s pomoshch'iu kDNK-zondov, komplementarnykh 3'-kontsu virusnogo genoma.

Venezuelan equine encephalomyelitis, Eastern equine encephalomyelitis and Sindbis viruses, as well as members of various serological groups of alphaviruses were identified using synthesized molecular probes complementary to 3'-terminus of the molecule of the appropriate genomic RNA: 32P-single-stranded kDNA and E. coli-cloned 32P-double-stranded kDNA. A high species-specificity of kDNA-probes was demonstrated. The sensitivity of the method was 1 ng of viral RNA overlayed on the nitrocellulose filter.

[Stabilizing selection in neonates for 2 weight-growth traits]. / Stabiliziruiushchii otbor u novorozhdennykh po dvum rostovesovym priznakam.

This study deals with the analysis of body weight and length augmentation in the group of newborns survived and died during the prenatal period. The effect of stabilizing selection for these characters was demonstrated. The analysis of dependence of the innate characters on the order number of pregnancy and parturition is accomplished. The advantages of the use of generalized characters of variability for revealing the stabilizing selection and of the possibility of using anthropometric characters of newborns in view of genetic monitoring are discussed.

[Use of an experimental analytical method for equilibrating nutrient broths for Clostridium perfringens type A growth and toxin formation]. / Ispol'zovanie éksperimental'no-analiticheskogo metoda dlia balansirovki zhidkikh pitatel'nykh sred dlia rosta i toksinoobrazovaniia Clostridium perfringens tipa A.

A successful attempt to use analytico-experimental approach to the evaluation of experimental data for the scientifically based calculation of the composition of complex culture media, intended for growing pathogenic microorganisms, has been made. The method is based on the evaluation of the specific growth-stimulating and toxin-forming activity of the components of a given culture medium, which are determined by the number of cells grown in the variants of the medium with the limited amount of one of its components. The use of the analytico-experimental balancing method makes it possible to develop culture media with the optimal composition ensuring the definite yield of the target product rather quickly and economically by experimenting on the minimal number of variants equal to the number of the components of the medium. The investigation carried out by means of the analytico-experimental method has revealed that on the basis of peptic serum albumin hydrolysate, pancreatic casein hydrolysate and fodder yeast extract, alongside the culture medium described in an earlier work and containing these components in the proportion 4:2:1, two other media, containing the above components in the proportion 2:4:1 and 3:4:2, can be obtained, these media providing the optimal conditions for, respectively, the toxin formation and growth of C. perfringens, type A.

[Effect of iron on the growth and toxin formation of Clostridium perfringens type A cultures]. / Izuchenie vliianiia zheleza na rost i toksinoobrazovanie kul'tur Clostridium perfringens tipa A.

The influence of iron at different concentrations on the growth and toxin formation of the cultures of C. perfringens strain 28 BP6K, type A, in media having different composition and protein base has been studied. As revealed by the results of these studies, bivalent iron at concentrations of 1-30 mg%, while having no essential influence on the growth and development of the culture, not only produces no stimulating effect on toxin formation, but even inhibits it. The concentrations of iron, both producing the optimum effect on toxin formation and inhibiting it, are not identical for different kinds of culture media and depend on their nature and composition. In culture media with fodder yeast extract added, and especially in media based on fermentative fodder yeast hydrolysate, the cultures have shown the increased stability of toxin formation in the presence of higher concentrations of iron.