Biomedical subjects

S A Nazarenko

Publications and source records attributed to S A Nazarenko.

At least 19 recordsLinked to original sources

PubMed2005

Plasma antioxidant activity and chromosome aberrations in humans exposed to long-term low-dose gamma-irradiation.

Plasma antioxidant activity was evaluated in the lecithin-Fe(2+) model system and cytogenetic studies were carried out in 16 men. A relationship between elevated antioxidant activity of the plasma and increased level of chromatid aberrations and with percentage of aberrant cells was detected in the experimental group, but no correlation was found between antioxidant activity and the integral dose of gamma-irradiation and rate of its accumulation. An assumption was made about exhaustion of the buffer capacity of the antioxidant defense system resulting from long-term exposure to unidentified factors of technogenic nature increasing plasma antioxidant activity and level of chromosome aberrations. In subjects with high level of antioxidant defense, naturally low antioxidant activity and low percentage of chromatid aberrations were probably maintained.

Adolescent↗

PubMed2005

[Interphase cytogenetics in estimation of genomic mutations in somatic cells].

The review considers the current state, possibilities, and perspectives of using interphase cytogenetics in the estimation of genomic mutations in human and animal somatic cells for aims of genetic toxicology and genetic instability analysis. Possible mechanisms underlying action of mutagens causing numeric chromosome aberrations are discussed.

Animals↗

PubMed2005

[Comparison of the rates of aneuploidy occurrence in quiescent and dividing cells of humans exposed to adverse environmental factors].

Fluorescence in situ hybridization (FISH) was used to compare aneuploidy rates in four autosomes and two sex chromosomes in interphase nuclei of noncultivated (quiescent) and cultivated (induced to divide with phytohemagglutinin (PHA)) leukocytes in people engaged in nuclear-chemical industry and in a control group of people not exposed to mutagenic factors occupationally or at home. The overall rates of numerical chromosome aberrations for all of the six chromosomes studied showed little difference, although a higher rate of loss of the X- and Y-chromosomes was observed in the exposed group. In individuals exposed to several adverse environmental factors, the overall rate of numerical chromosome aberrations in cultivated cells after at least one DNA replication cycle exceeded that in noncultivated cells by 52% (P = 0.01), whereas only a trend for its increase was observed in the control group (23%, P = 0.25). Thus, the effect of adverse environmental factors in humans caused more than a twofold increase in the difference between the rates of aneuploid cells in cultivated and non-cultivated leukocytes in the exposed group as compared to control. It is conjectured that cell division is accompanied by the expression of potential damage of mitotic chromatid segregation apparatus accumulated in vivo. These defects, realized during cell division, bring about numerical chromosome aberrations.

Adult↗

PubMed2005

[Germline mutations of tetranucleotide DNA repeats in families with normal children and reproductive pathology].

We have previously reported a high rate of tetranucleotide DNA repeat mutations, including mutations of both germline and somatic origin, in spontaneous human abortuses. To analyze in more detail mutational microsatellite (MS) variability in meiosis and its possible association with disturbed embryonic development, we have conducted a comparative study of mutation rates of a complex of 15 autosomal tetranucleotide MSs in 55 families with healthy children and in 103 families that have had spontaneous abortuses with normal karyotypes. In the families with miscarriage, the gametic MS mutation rate was higher than in the families with normal reproductive function (4.36 x 10(-3) versus 2.32 x 10(-3) per locus per gamete per generation), but this difference was statistically nonsignificant (P = 0.25). No association of MS mutations with familiar miscarriage was found. Mutations at the MS loci studied were recorded almost 3 times as often in spermatogenesis as in oogenesis, which is likely to result from a greater number of DNA replication cycles in male germline cell precursors than in female ones. Mutations increasing and reducing the MS sequence length appeared at virtually the same rate. Changes in MS DNA sequence length per one repeated element, i.e., single-step mutations (93% of cases) exceeded all other events of allele length change. The highest number of mutations (81.2%) was found in longer alleles. This distribution of mutations by size, direction, and parental origin corresponds to the multistep mutation model of their emergence via mechanism of DNA strand slippage during replication.

Abortion, Habitual↗

PubMed2005

[Scoring criteria of aneuploidy frequency in interphase nuclei by fish-analysis].

Principles and approaches of assessment of numerical chromosome abnormalities in interphase nuclei by fluorescent in situ hybridization technology are reviewed. The authors' own scoring criteria of results of hybridization of centromere-specific DNA-probes with chromosomal targets in somatic cells by dual color FISH-analysis are suggested. Use of these scoring criteria allows to reduce the level of artificial hypoploidy, whose its frequency becomes similar to that of hyperploidy. This fact indicates that chromosomal nondisjunction is a major mechanism of aneuploidy induction, rather than of chromosome loss.

Adult↗

PubMed2004

[Analysis of the frequency of spontaneous aneuploidy in human somatic cells using interphase cytogenetic technology].

The frequency of spontaneous aneuploidy of the four autosomes and sex chromosomes in the interphase nuclei of cultivated and uncultured lymphocytes from clinically healthy men was examined by use of two-color fluorescent in situ hybridization (FISH). It was shown that in uncultured cells from the individuals examined autosomal nullosomies were practically not detected (the frequency 0 to 0.01%). At the same time, the frequency of such cells with either Y, or X nullosomy was at least an order of magnitude higher (about 0.15%). This frequency was comparable with the level of Y- or X-disomic cells, and also with autosomal monosomies, precluding from considering the X-nullosomic cells as hybridization artifacts. During lymphocyte cultivation, a statistically significant increase in the total frequency of Y- or X-nullosomic cells was observed already after the first cell division cycle. Thus, interphase FISH analysis is a sufficiently sensitive method enabling detection of higher, compared to the autosomes, loss of sex chromosomes in the process of cell division, a phenomenon observed during replicative cell aging, as well as during natural aging of the organism. Male cells with the de novo lost singular X chromosome, probably, switch to apoptosis and do not survive during further life of a cell population. The frequency of total aneuploidy in human somatic cells with the correction for the resolution capacity of the interphase FISH analysis constituted 5.62 and 6.90% for uncultured and cultivated cells, respectively. This aneuploidy level is close to that in spermatozoa. The data obtained can serve as the basis for the examination of the aneugenic (aneuploidy-inducing) genotoxic effects and for the analysis of interindividual genetic instability.

Aneuploidy↗

PubMed2004

[Search for transcribed segments in the region of q14.3 of human chromosome 13 in silico].

Using computer-aided genomic methods, a complete map of the expressed sequence tags (EST) located in the human genome region 13q14.3 between the STS markers, D13S810 and D13S1469, was constructed. A total of 62 EST clusters were formed, of which 12 clusters corresponded to the already known human genes, 4 clusters represented pseudogenes, and 10 clusters were new human genes. The use of the method of reverse transcription in combination with polymerase chain reaction (RT-PCR) provided experimental confirmation of the existence of mRNA transcripts for the novel human genes revealed in silico.

Base Sequence↗

PubMed2004

[Maternal cell contamination of cultures of spontaneous abortion fibroblasts: importance for cytogenetic analysis of embryonic lethality].

The results of standard cytogenetic analysis of the long-term cultures of embryonic fibroblasts of 478 first-trimester spontaneous abortions were retrospectively reviewed. In 16% of embryos with cytogenetically confirmed karyotype 46,XX, the Y chromosome was found by molecular genetic methods. Prior to obtaining the chromosome preparations, the cell cultures of Y chromosome-carrying embryos were maintained for a longer period than the cultures of embryos without the Y chromosome. Thus, a late entry of a culture into the logarithmic growth phase serves as marker of maternal cell contamination. We developed a mathematic model for assessment of karyotype incidence and the "sex ratio" of spontaneous abortions, taking into account risk of maternal cell contamination in extraembryonic tissue cultures. Thus estimated, the incidence of chromosomal abnormalities in the studied sample increased from 54.6 to 60.3% and the expected sex ratio increased from 0.66 to 1.02 in abortions with normal karyotype. Using molecular analysis of inheritance of polymorphic DNA markers of six autosomes (2, 11, 16, 19, 20, and 21), the proposed model was tested on 60 embryos with karyotype 46,XX and their parents. Numerical chromosome abnormalities were revealed in uncultured tissues of seven abortions (11.7%), including four without the Y chromosome, which is in a good agreement with the expected incidence of karyotype abnormalities (8.3%) predicted by our model. In view of this, estimating risk of maternal cell contamination in embryonic cell cultures seems necessary for correctly assessing the effect of natural selection in humans, for understanding the mechanisms that determine the sex ratio, and for evaluating the precision of prenatal cytogenetic diagnosis of chromosomal abnormalities.

Abortion, Spontaneous↗

PubMed2004

[Human microsatellites: mutation and evolution].

Microsatellites (MSs) are short tandem DNA repeats with the repetitive motif of two to six nucleotides, forming tracts up to hundreds of nucleotides long. Notwithstanding the active use of MSs in genetic studies of various biological problems, the reasons for their wide occurrence in the genome, their possible functions, and mutational behavior are still unclear. The mutation rate in MS repeats is on average several orders of magnitude higher than in the remaining DNA, which allows for direct estimation of evolutionary transformation rate in nucleotide sequences of the genome. Mutation process in MSs is species-specific; furthermore, within a species it differs among loci with different repeat size, among alleles of one locus, and among individuals of different sex and age. Most MS mutations are caused by DNA slippage during replication but the probability of this event depends on the locus. In this review, a number of models of MS evolution are discussed, which account for the relationship between mutation rate and allele size, different mutation direction in alleles of different size, and the appearance of point mutations within repeat tracts restricting allele size. The MS evolution is considered mainly in the context of selective neutrality, although there is evidence showing functional significance of some variants of tandem repeats and thus their possible selective value.

Evolution, Molecular↗

PubMed2004

[Multiaberrant cell formation caused by exposure to internal densely-ionizing irradiation].

The origin of multiaberrant cells (MACs) was studied by comparing the structure and intensity of chromosome damage in peripheral blood lymphocytes of two groups of people: workers of Siberian Chemical Plant differing in the content of plutonium-239 in their bodies, and inhabitants of a non-polluted settlement (control group). Plutonium-239 is known to be a long-lived densely-ionizing source of alpha-radiation with high linear energy delivery; therefore, it has a stronger effect on cell hereditary structures than gamma-rays. In persons with the content of plutonium-239 higher than 13 nCu, the frequency of MAC was 0.105% which at least tenfold exceeds the spontaneous level. The chromosome-type aberrations that are usually induced by ionizing radiation predominated in MACs. Our results suggest that MAC formation may be caused by internal body irradiation with the incorporated sources of densely-ionizing radiation.

Adult↗

PubMed2003

[A search for mutations in the DIA1 gene in case of hereditary methemoglobinemia type I in the iakut population].

In the patients with enzymopenic hereditary methemoglobinemia type I, a disease widely distributed on the territory of Yakutia, a search for the mutations in exons 3 and 4 of the DIA1 gene encoding NADH-cytochrome b5 reductase was carried out. It was shown that Yakut patients have none of three missence mutations, Arg57Gln, Leu72Pro, and Val105Met, described in case of this disease in the neighboring populations, Chinese and Japanese, inhabiting the territories south of Yakutia.

Asian People↗

PubMed2003

[Molecular cytogenetic characteristics of chromosome imbalance in cells of spontaneous human abortion fetuses with low proliferative activity in vitro].

Karyotyping of noncultivated cells of 60 first-trimester spontaneous abortions (blighted ova and missed abortions) was carried out using fluorescence in situ hybridization (FISH) with centromere-specific DNA probes for all chromosomes of the karyotype. Conventional cytogenetic study of these abortions was impossible because of cell culture failures. The algorithm is proposed for molecular cytogenetic FISH analysis of interphase karyotypes. Chromosome abnormalities were found in 32 fetuses (53.3%). In groups of missed abortions and blighted ova, the frequency of numerical chromosome abnormalities was 50 and 60%, respectively. Both the numerical chromosome abnormalities typical of spontaneous human abortions (autosomal trisomies, sex chromosome aneuploidy, and polyploidy) and a relatively rare type of genomic imbalance unidentifiable by standard cytogenetic analysis (autosomal monosomies 7, 15, 21, and 22 in mosaic state) were observed. The frequency of these type of chromosome abnormalities comprised 19% of all known karyotype abnormalities determined in spontaneously perished embryos. Note that the level of confined placental mosaicism in embryos with low cell proliferative activity was 25%, which is substantially higher than the corresponding parameter (1-2%) determined by prenatal diagnosis of chromosome abnormalities in developing embryos. The results of interphase FISH analysis of cells with low proliferative activity in vitro suggest that the pathology of early fetal development and missed abortion in humans are associated with a wider spectrum of chromosome abnormalities.

Abortion, Spontaneous↗

PubMed2002

[Comparative genomic hybridization as a new method for detection of genomic imbalance].

Comparative Genomic Hybridization (CGH) is a molecular cytogenetic analysis that allows identification of genomic changes by comparing the copy number of DNA sequences in cells of tested tissue and the reference specimen. CGH is based on competitive suppressive in situ hybridization of two differently labeled DNA probes (tested and reference, karyotypically normal, fluorochrome-labeled DNAs) with metaphase chromosomes of a healthy subject. First described by Kallioniemi et al. in 1992, the CGH assay has been widely used for identification and characterization of both numerical and structural chromosome abnormalities in cells of different tissues at various pathological conditions in humans, especially in tumor diseases. We discuss the specific features and quality control of comparative genomic hybridization, its advantages and limitations in detection of genomic imbalance and the prospects for development of this technology.

Chromosomes, Human↗

PubMed2002

[Polymorphism of trinucleotide repeats at loci FRAXA and FRAXE in the population of Tomsk].

Polymorphism of CGG and GCC trinucleotide repeats, whose expansions at the FRAXA and FRAXE loci have been identified as causative mutations in two forms of mental retardation, was studied in Slavic population of Tomsk. At the FRAXA locus a total of 31 allelic variants ranging from 8 to 56 copies of CGG repeat with two modal classes of 28-29 and 18-20 repeat units (with the frequencies of 24.6 and 11.5% respectively) were revealed. Compared to other populations, this locus was characterized by unusually high frequency of intermediate alleles with the sizes of more than 40 CGG repeat units (12.4%). Since intermediate repeats of the FRAXA locus were more prone to instability than normal alleles, it was suggested that Slavic population of Siberia had higher risk of the development of FMR1 dynamic mutations, giving rise to the Martin-Bell syndrome. The FRAXE allele frequency distribution was demonstrated to be normal with 18 allelic variants ranging from 9 to 27 GCC repeat units. In the population of Tomsk this locus had higher than in other populations frequency (26.7%) of short (less than 15 repeat units in size) alleles. In addition, in the Tomsk population both loci were characterized by high level of heterozygosity and low frequencies of modal allele classes. These results can be explained by the high level of outbreeding typical of the population of Siberia.

Fragile X Messenger Ribonucleoprotein 1↗

PubMed2002

[Detection of aneuploidy in spontaneous abortions using the comparative hybridization method].

Comparative genomic hybridization (CGH) technique was used to examine a set of ten spontaneous abortions whose cell cultures were characterized by the lack of proliferation in vitro, and thereby, were not available for the analysis by means of routine cytogenetic methods. Five abortions (50%) had aneuploidy of autosomes, including trisomy 10, 14, 18, and 21, and monosomy 22. The latter variant of unbalanced chromosomal abnormalities is rarely detected in spontaneous abortions by use of conventional cytogenetic methods. The results were validated by using fluorescent in situ hybridization (FISH) analysis with centromere-specific DNA probes. Embryos with trisomy 10 and monosomy 22 displayed mosaicism with the frequencies of abnormal cell clones constituting 68 and 33% respectively. The advantages and limitations of the applying of CGH technique for detection of genomic abnormalities in both nonmosaic and mosaic forms are discussed.

Abortion, Spontaneous↗

PubMed2001

[Effect of the frequency of X-monosomal cell clone on variability of anthropometric indicators in Shereshevsky-Turner syndrome].

Using methods of mathematical statistics the relationships were determined between 31 anthropometric traits (ATs) and the frequency of the X-monosome cell clone in 53 patients with either 45, X-monosomy or mosaic forms (45,X/46,XX) of the Shereshevsky-Turner syndrome (STS). AT variations were studied in patients untreated with growth hormone and in 25 control fertile healthy women. In 29 patients, the degree of mosaicism was assessed by interphase FISH analysis using X-centromer-specific DNA probe hybridized to the cell nuclei of two types of tissues differing in embryonic origin (lymphocytes and oral epithelium, originating from meso- and ectoderm, respectively). The level of X-monosome mosaicism had a substantial effect on some AT, which depended similarly on the proportion of X-monosome cells in tissues of different embryonic origin. Statistically significant negative correlations were revealed between the size of X-monosome clone and 13 height-weight, longitudinal, and circumference traits, whereas positive correlations were characteristic of seven mostly width traits. Eleven ATs showed no correlation with the X-monosome cell clone. Discriminant analysis of all ATs, whose variations depended on the frequency of X-monosome cell clone, was found to be an essential tool for precise classification of both STS patients with different degree of mosaicism and healthy women. Based on these results, the set of ATs characteristic of the STS phenotype was identified.

Adolescent↗

PubMed2001

[Tissue-specific placental mosaicism for autosomal trisomies in spontaneous human abortuses: mechanisms of formation and phenotypic effects].

The frequencies of autosomal trisomies in extraembryonic human tissues were estimated in the cases of different abnormalities of prenatal development, from the confined placental mosaicism (CPM) with either relatively normal embryogenesis or restricted intrauterine growth to spontaneous abortion. A tissue-specific compartmentalization was found to be characteristic of cell lines with trisomies for individual autosomes. Analysis of various phenotypical effects of chromosomal aberrations associated with mosaicism is necessarily required to understand the mechanisms and factors responsible for tissue chromosomal mosaicism. Based on analysis of the cell karyotype during prenatal diagnosing of chromosome aberrations in tissues of both extraembryonic and embryonic origin, in 1996, Wolstenholme proposed a model of CPM for individual chromosomes. According to the model, the distribution of cell lines with autosomal trisomies between extraembryonic tissues depends on the ratio between meiotic and mitotic mutations early in embryonic development. However, the model cannot be used to study tissue chromosomal mosaicism in spontaneous abortions, because little information is available on cell karyotype in embryonic tissues themselves after intrauterine fetal death. In this work, a model of tissue-specific chromosomal mosaicism was suggested based on the data on cell karyotype determined in extraembryonic tissues alone, which can be helpful in evaluating the contribution of tissue chromosomal differences into the etiology of early intrauterine death. Along with the experimental evidence, comparative analysis of the two models indicated that the meiotic chromosome nondisjunction plays the major role in trisomy formation and the resultant spontaneous arrest of embryonic development. Other factors responsible for tissue-specific distribution of chromosomal aberrations are also discussed. These are differences in cell proliferative activity, as well as changes in compartmentalization and migration of cells with abnormal karyotypes.

Abortion, Spontaneous↗

PubMed2001

[Impaired epigenetic gene activity regulation and human diseases].

The epigenetic (i.e. heritable states that are mediated by changes in DNA other than nucleotide sequence) mechanisms of regulation of gene expression have been recently the focus of intensive studies. Genomic imprinting refers to the epigenetic gene marking that results in monoallelic expression. The epigenetic mechanism of imprinting is based on the gamete-specific methylation of some mammalian genes, which restricts their expression on one of the parental chromosomes. The imprinted genes control fetal and placental development, cell proliferation and adult behavior. Changes in the normal imprinting patterns give rise to numerous genetic diseases, including cancer. Examining the molecular processes that mediate these methylation genome changes will give use a great insight into the mechanisms of regulation of gene activity and into the etiology of some human genetic diseases.

Alleles↗