Relevance. Genetic determinants of multifactorial diseases are critical for assessing the risk of genetic diseases and their prevention, especially among the workforce exposed to industry-related dangerous and aggressive occupational factors. Firefighters perform combat service duties in extremely unfavorable industrial environments associated with occupational diseases. Respiratory diseases are among the pathologies with highest incidence rates in firefighters. In addition to environmental factors, the development of these diseases (especially bronchial asthma and chronic obstructive pulmonary disease) is largely driven by impaired immune system – one of the three critical regulatory systems involved in pathogenetic mechanisms of various diseases, including inflammatory diseases. Polymorphic gene variants of inflammatory mediators – in particular cytokine genes and their receptors – mediate the immune system activity and can impact its functionality, susceptibility, or resistance to disease development.The objective is to analyze how interleukin 1β, 4, 6, 13, TNF and interleukin 6 receptor genes, as well as their polymorphic variants are associated with respiratory diseases and changes in the biomarker profiles showing immune response intensity in the employees of the Federal Firefighting Service of the EMERCOM of Russia. Methodology. Molecular genetic profiling and immunology tests were performed in 70 employees of the Federal Firefighting Service of the EMERCOM of Russia to analyze proinflammatory cytokine genes and their polymorphic variants. Real-timePCR was used to analyze the interleukin 1β, 4, 6, 13, TNF and interleukin-6 receptor genes and their polymorphic variants. Immunological examination evaluated the blood monocyte subpopulations and relative count of type 2 T-helper cells; flowcytometry and immunochemiluminescence assays were used to evaluate immune response biomarkers in peripheral blood and total immunoglobulin E (IgE) respectively.Results and discussion. The analysis provides evidence that minor alleles of most polymorphic cytokine genes are associated with a proinflammatory phenotype, which is especially apparent for genotypes comprising several minor alleles. Allele A at rs1 800 629 polymorphic TNF gene exposed a direct correlation with respiratory diseases, as well as with increased monocyte differentiation. Allele T of IL4 rs2243250 gene and allele A of IL1β rs16944 gene were associated with increased proinflammatory monocyte count. Elevated count of type 2 T-helper mediators of humoral response, especially of allergicorigin, was observed in individuals with C/C IL6 rs1 800 795 and G/G IL1β rs16944 genotype.Conclusion. The obtained results suggest that evaluation of cytokine gene polymorphic variants is a promising strategy to predict the risk of respiratory diseases in firefighters. Prompt assessment of genetic predisposition to a proinflammatory phenotype paves the way towards prevention and early detection of inflammatory diseases in this cohort of workers.

Relevance. As an epidemiologically proven consequence of the Chernobyl NPP accident, circulatory diseases are among the leading morbidities in liquidators. To predict the development of adverse cardiovascular events in patients with metabolic syndrome, there is the ongoing search for informative laboratory markers.The objective is to show how osteopontin, osteoprotegerin, fetuin-A, and risk factors for genetic circulatory disorders are associated with traditional risk factors for circulatory disorders in Chernobyl nuclear power plant accident liquidators suffering metabolic syndrome. Another objective is to explore the perspectives to use these indicators to forecast coronary atherosclerosis progression.Methods. The study group included 50 male liquidators of the Chernobyl nuclear power plant accident who suffered metabolic syndrome. The patients were split in two groups depending on osteopontin concentration in blood serum, i.e. above or under the upper reference limit. Medical history data, biochemical parameters, including inflammatory proteins, osteoprotegerin, fetuin-A, and genotyping of polymorphic variants of genes associated with the risk of circulatory diseases were analyzed. A control group of 30 conditionally healthy men was formed to determine the normal osteopontin, osteoprotegerin and fetuin-A values in blood serum.Results and discussion. With osteopontin value exceeding 21.4 ng/mL, the liquidators’ medical history showed 1.5 times higher frequency of myocardial infarction, 2.5 times higher frequent history of acute cerebral circulation disorder; ischemic heart disease was associated with type 2 diabetes mellitus. It was shown that the group of liquidators (osteopontin over 21.4 ng/ml) was characterized by a reliable increase in atherogenicity coefficient and osteoprotegerin level. Meanwhile, when compared to the control group, the same group of patients showed lower fetuin-A values and elevated high-sensitivity C-reactive protein, homocysteine, leptin and ghrelin. It was found that in liquidators, the presence of the A allele in the vitamin B12-dependent methionine synthase (MTR) gene (2756 A>G) is associated with more pronounced biochemical markers of atherosclerosis progression compared to GG genotype carriers.Conclusion. Osteopontin performs a protective role in tissue damage, being is practically undetectable in normal conditions. However, in case of pathology its value increases dramatically. In patients with metabolic syndrome, decreased fetuin-A and osteopontin values exceeding 21.4 ng/mL require additional examination with a focus on cardiovascular pathology (coronary artery calcinosis), as well as a dual-energy X-ray absorptiometry to ensure early detection of diminished bone mineral density and body mass. It was found that in liquidators, the presence of A-allele (genotypes AA and AG) in the MTR 2756 A>G gene is characterized by deeper atherogenic changes in the lipid spectrum, increased atherogenicity coefficient and decreased adiponectin content. This justifies the need for genotyping to build individual forecast for atherosclerosis progression in this category of patients.

Millions of people around the world are exposed to low doses of ionizing radiation from diagnostic computed tomography (CT) scans. Currently available data on the potential cancer risk after CT scans are contradictory and therefore demand further investigations. The aim of the current study was to obtain estimations of genome damage after CT scans in 42 non-cancer patients and to conduct a comparison of the results with 22 control subjects. The frequency of dicentric ring chromosomes and chromosome breaks was significantly increased in irradiated patients compared to the controls. The distribution of dicentrics among the cells demonstrated non-Poisson distribution that reflected non-uniform and partial-body radiation exposure. A fraction of patients followed Poisson distribution, which is typical for uniform whole-body exposures. Some patients demonstrated a level of dicentrics similar to the control subjects. The individual variations in the frequency and dicentric distribution suggested complex mechanisms of chromosome aberration induction and elimination that could be associated with individual radiosensitivity, as well as previous diagnostics that used ionizing radiation or the redistribution of small fractions of irradiated lymphocytes within the circulatory pull. In conclusion, CT scans may cause genome damage and possible increases in cancer risk. The introduction of a specific follow-up of such patients, especially in the case of repeated CT scans, is suggested.

Relevance. Professional activities of firefighters and rescuers are usually associated with aggressive chemical exposure with increased physical exertion and psychological stress. Therefore, for professional selection and monitoring the health status of firefighters and rescuers of EMERCOM of Russia it is necessary to evaluate the activity of cytochrome P450 isoenzymes that are directly involved in detoxification pathways in the liver.Intention. To evaluate the activity of the CYP3A4 enzyme by phenotyping methods and to establish the frequency of allelic variants of the gene of this enzyme (rs2740574 and rs4987161 polymorphisms) in firefighters and rescuers of EMERCOM of Russia for targeted treatment, rehabilitation and prevention.Methodology. Polymorphisms (rs2740574 and rs4987161) of the CYP3A4 gene and also CYP3A4 activity by the ratio of 6-β-hydroxycortisol / cortisol in the urine were determined during routine periodical medical examination of 64 rescuers and firefighters of rescue units of EMERCOM of Russia. The average age of examined persons was (29.8 ± 5.5) years; 30 of them are rescuers of the North-West Regional Search and Rescue Squad and 34 are firefighters of the territorial fire departments of St. Petersburg.Results and Discussion. According to the results of genotyping of rs2740574 polymorphism of the CYP3A4 gene, EMERCOM employees were divided into 2 groups depending on the presence or absence of a minor allele: “poor” and “rapid” metabolizers (9.4% and 80.6%, respectively). According to the results of genotyping of the rs4987161 polymorphism of the CYP3A4 gene, the examined were classified as “rapid” metabolizers, because patients with a minor allele were not identified. Depending on the ratio of 6-β-hydroxycortisol / cortisol in the urine, the activity level of CYP3A4 was “normal” in 67 %, “poor” in 13 % and “rapid” in 20 % of cases. The ratio of 6-β-hydroxycortisol / cortisol in the urine tended to increase with an increase in work experience and age. No relationship between the studied polymorphic variants of the CYP3A4 gene and the established enzyme activity was observed.Conclusion. Genotyping methods made it possible to identify allelic variants of the CYP3A4 gene that could affect the functionality of the enzyme; however, no association of the studied polymorphisms with enzyme activity was found. In such cases, in the absence of informative genetic markers, it is recommended to evaluate the enzyme activity by phenotyping methods.

Relevance. There is a need to evaluate doses retrospectively in Chernobyl nuclear power plant accident recovery workers without established external doses.Intention: To assess the ability of cytogenetic analysis to estimate external radiation doses retrospectively in Chernobyl nuclear power plant accident recovery workers exposed to low-dose radiation in the remote period.Methodology. Cytogenetic biological indication and biological dosimetry were performed in Chernobyl nuclear power plant accident recovery workers 27–30 years after their participation in recovery works. Stable and unstable chromosome aberrations were assessed in peripheral blood lymphocytes.Results and Discussion. The analysis of unstable chromosome aberrations showed that 45.1 % of Chernobyl nuclear power plant accident recovery workers had radiation markers more frequently than in the comparison group. Biological doses were retrospectively evaluated in 18 % of Chernobyl nuclear power plant accident recovery workers and ranged within 14–48 cGy. Specific anamnestic factors should be assessed while evaluating doses retrospectively.Conclusion. Analysis of stable chromosome aberrations allows retrospective dosimetry after low-dose exp sure if external dose is unavailable. Based on this, adverse health effects of low-dose exposure can be assessed and reimbursed in Chernobyl nuclear power plant accident recovery workers.

As children are more susceptible to ionizing radiation than adults, each nuclear accident demands special attention and care of this vulnerable population. The Chernobyl nuclear disaster occurred in a region populated with a large number of children, but despite all efforts and expertise of nuclear specialists, it was not possible to avoid casualties. As vast regions of Ukraine, Belarus and Russia were exposed to doses of ionizing radiation, which are known to be related with different diseases, shortly after the accident medical surveillance was launched, which also included analysis of genome damage. Child population affected by internal and external radiation consisted of subjects exposed prenatally, postnatally (both evacuated and non-evacuated), born by irradiated fathers who worked as liquidators, and parents exposed environmentally. In all groups of children during the last 30 years who were exposed to doses which were significantly higher than that recommended for general population of 1 mSv per year, increased genome damage was detected. Increased genome damage includes statistically higher frequency of dicentric and ring chromosomes, chromated and chromosome breaks, acentric fragments, translocations, and micronuclei. The presence of rogue cells confirmed internal contamination. Genome instability and radiosensitivity in children was detected both in evacuated and continuously exposed children. Today the population exposed to ionizing radiation in 1986 is in reproductive period of life and follow-up of this population and their offspring is of great importance. This review aims to give insight in results of studies, which reported genome damage in children in journals without language restrictions.

Cytogenetic dosimetry plays an important role in the triage and medical management of affected people in radiological incidents/accidents. Cytogenetic biodosimetry uses different methods to estimate the absorbed dose in the exposed individuals, and each approach has its advantages and disadvantages. Premature chromosome condensation (PCC) assay presents several advantages that hopefully fulfill the gaps identified in the other cytogenetic methods. To introduce this technique into the panel of other cytogenetic methods, a calibration curve for PCC after γ-irradiation was generated for our laboratory.

Qualitative and quantitate analysis of DNA methylation in situ at the level of cells, chromosomes and chromosomal domains is extremely important for the diagnosis and treatment of various diseases, the study of ageing and the consequences of environmental impacts. An important question arises, whether the revealed in situ methylation pattern reflects DNA methylation per se and (or) availability of the DNA for antibodies, which in turn depends on the peculiarities of chromatin structure and chromosome condensation. These events can lead to an incorrect evaluation of the actual pattern of DNA methylation. To avoid this shortcoming as far as possible, we have modified the most widely used method of revealing 5-methylcytosine in situ with monoclonal antibodies. Here we have shown that the detection of DNA methylation staining of chromosomes including C-heterochromatin, chromosomal arms and sister chromatids is drastically dependent on pretreatment of chromosomal preparations for immunocytochemical study using fluorescent antibodies. Using undifferentiated stem cells of mouse embryonal carcinoma line F9, it has been found that change in preparations storage results in a sharp fluorescence decrease up to complete disappearance of the signal in centromeric heterochromatin. With the help of the method described in the work, we have first revealed the asymmetry of sister chromatids methylation in metaphase chromosomes of F9 cell and lymphocytes of human periphery blood. This may lead to asymmetry of transcriptional signature of daughter cells after division. The proposed here modification of 5-methylcytosine detection in situ provides a more complete characterization of methylation of chromosomes and chromosomal domains, compared to previously published methods.

Qualitative and quantitative analysis of DNA methylation in situ at the level of cells, chromosomes, and the chromosomal domain is extremely important in diagnosis and treatment of various pathologies, as well in studies of aging and the effects of environmental factors. Yet, the questions remain unresolved of whether the detectable in situ methylation patterns correspond to the actual DNA methylation per se and/or reflect the accessibility of DNA to antibodies, which depends on the structural features of chromatin and chromosome condensation. Thus, this phenomenon can result in an incorrect determination of the real DNA methylation pattern. In order to eliminate this disadvantage to the extent possible, we modified the commonly used methodology of in situ detection methylcytosine by means of monoclonal antibodies. In this study, we show that the efficiency of immunofluorescent labeling for 5-methylcytosin in centromeric heterochromatin, chromosome arms and sister chromatids is significantly affected by the conditions of pretreatment of chromosome preparations. We used undifferentiated murine embryonic F9 cells to show that variations in the conditions of storage of chromosome preparations can lead to a sharp reduction of labeling intensity and even disappearance of the fluorescence signal in centromeric heterochromatin. Using the developed method, we discovered asymmetric methylation of sister chromatids in F9 cells and in human peripheral blood lymphocytes. This phenomena can lead to asymmetric cell division and asymmetric transcriptional status in daughter cells. Thus, the modified methodology for detection of 5-methyl cytosine in situ can provide for a more precise assessment of methylation of chromosomes and chromosomal regions.

The incidence of unstable chromosome aberrations in peripheral blood lymphocytes from unirradiated control subjects was analyzed using cytogenetic data obtained from 9 cytogenetic laboratories located in Moscow, St.-Petersburg, Obninsk, and Dubna (Russia). The objective of this study was to estimate the level and spectrum of spontaneous chromosome aberrations in human lymphocytes. 1140 blood samples were taken from 1112 subjects (594 men and 546 women) aged 1 to 72. The total metaphase number was 466795. The uniform Giemsa method for peripheral blood lymphocyte cultures was used. After counting 466795 metaphases, 4288 chromosomal aberrations of various types were classified. The most frequent types of aberrations were acentrics and chromatid deletions. They made up 90% of the total number of aberrations. The remaining 10% were exchange aberrations. The number of chromosome exchanges (dicentrics and centric rings) was twice the number of chromatid exchanges. Overall, the portion ofcells with chromosomal or (and) chromatid aberrations was 0.89 +/- 0.01%; the frequency of acentrics was 0.29 +/- 0.01; the frequency of dicentrics was 0.046 +/- 0.003; the frequency of unstable chromosome aberrations was 0.35 +/- 0.01; and the frequency of chromatid aberrations was 0.57 +/- 0.01 per 100 cells.

The incidence of unstable chromosome aberrations in peripheral blood lymphocytes from unirradiated control subjects was analyzed using cytogenetic data obtained from 9 cytogenetic laboratories located in Moscow, St.-Petersburg, Obninsk, and Dubna (Russia). The objective of this study was to estimate the level and spectrum of spontaneous chromosome aberrations in human lymphocytes. 1140 blood samples were taken from 1112 subjects (594 men and 546 women) aged 1 to 72. The total metaphase number was 466795. The uniform Giemsa method for peripheral blood lymphocyte cultures was used. After counting 466795 metaphases, 4288 chromosomal aberrations of various types were classified. The most frequent types of aberrations were acentrics and chromatid deletions. They made up 90% of the total number of aberrations. The remaining 10% were exchange aberrations. The number of chromosome exchanges (dicentrics and centric rings) was twice the number of chromatid exchanges. Overall, the portion ofcells with chromosomal or (and) chromatid aberrations was 0.89 +/- 0.01%; the frequency of acentrics was 0.29 +/- 0.01; the frequency of dicentrics was 0.046 +/- 0.003; the frequency of unstable chromosome aberrations was 0.35 +/- 0.01; and the frequency of chromatid aberrations was 0.57 +/- 0.01 per 100 cells.

Russian citizens who were irradiated because of radiation disasters, nuclear weapons testing and some other sources have a right to some social support and financial compensation. In order to get this compensation people have to prove that they were irradiated. As it is, not all victims for a variety of reasons have formal documents. Thus they apply for cytogenetic investigation to prove irradiation months, years and even decades after irradiation. Since 1992 the cytogenetic investigations related to radiation exposure were performed in NRCERM for more than 700 people. At the beginning of this investigation FISH method was not certified as a biodosimenty test in Russia. Only dicentric analysis was approved as a proof of irradiation. It is known that the rate of dicentrics decrease in time, but the residual level of cytogenetical markers could be revealed a long time after a radiation accident. Thus the dicentric analysis was performed for the people who applied for biological indication of radiation exposure at that time. Rates of dicentrics exceeding control levels were revealed in half the people who applied for radiation conformation. Now FISH method is certified in Russia and both cytogenetic tests of biodosimetry (dicentrics and FISH) are available for all corners. Increased levels of translocations were found in 8 cases (the dose rate from 0.16 to 0.64 Gy). On the basis of the results of cytogenetic tests official documents were supplied to these people and they were entitled to apply for radiation exposure compensation. Thus cytogenetic tests are very effective and in some cases the only possible way for the victims to prove irradiation exposure and to apply for radiation exposure compensation a long time after an accident. (C) 2011 Elsevier Ltd. All rights reserved.

The aim of this investigation was to reveal a possible correlation between chromosomal aberrations and the health status of Chernobyl clean-up workers who suffered from a low dose of ionizing radiation. Unstable chromosomal aberrations in peripheral blood lymphocytes were investigated in 491 Chernobyl clean-up workers. Information about lifestyle factors (all persons) and medical history (212 persons) was collected. Connections between the rate of chromosomal aberrations and some types of diseases were found. It was also found that Chernobyl clean-up workers with oncological diseases and hypertension had increased rates of chromosomal aberrations. Positive correlations between the grade of hypertension and the level of chromosomal aberrations (r = 0.20, p < 0.01) was revealed. Further investigations need to be carried out in order to understand the mechanisms of this connection.

Cytogenetic studies in rescue rangers of the Russian Ministry of Emergencies has shown that this category of specialists are exposed to genotoxic factors during their professional activity. The level of induction of cytogenetic injuries of rescue team members depended on labor conditions, genotype (glutathione-S-transferase M1 and T1 xenobiotic detoxication genes), and tobacco smoking.

This investigation was performed to test a supposition about the influence of disturbances in antioxidative system on cytogenetical parameters in Chernobyl' clean-up workers. It was shown that some cytogenetical parameters straightly correlated with the parameters of oxidative stress, while other cytogenetical parameters show just reverse correlations. Apparently, these relationships are not of cause-and-effect type, but they reflect a complex processes occurring in humans for a long period after radiation exposure.

Cytogenetic analysis performed 4-13 years after the Chernobyl accident showed an elevated frequency of acentrics, chromatid exchanges, dicentrics and rinks in Chernobyl cleanup workers compared to the control group. Cytogenetic data were analyzed according to the information on exposure to radiation (the year when the cleanup workers worked at the Chernobyl station, doses rates, time elapsed since exposure to radiation, and cytogenetic examination) and some lifestyle factors. The data obtained suggested that some types of chromosome aberrations could be influenced by the action of different environmental factors or lifestyle factors. The frequency of acentrics was correlated with the age of the cleanup workers, and the increased chromatid exchange frequency was attributed to smoking. The numbers of dicentrics and rings suggested a genotoxic effect of ionizing radiation that is still present over 13 years after the exposure. (C) 2003 by Radiation Research Society.

A cytogenetic study was carried out on 359 clean-up workers who worked at the Chernobyl station in 1986-1989. The investigation was performed 6-12 years after irradiation. Chromosome type damages, i.e. double fragments, dicentrics and rings were significantly increased in the cleanup workers compared to the control. Chromatid exchanges were found only in the clean-up workers. A temporal change of radiation makers was also investigated based on the data of 243 persons who worked at Chernobyl in 1986. The temporal variation of dicentric frequency shows an inexplicable tendency towards the increase of dicentrics rate for the period of 8-12 years after irradiation. The association between the frequency of different types of chromosomal aberrations and such variables as smoking habits, coffee, tea, alcohol consumption, etc. was also analysed using a stepwise multiple regression analysis. A statistically significant association was only observed between smoking and chromatid exchanges. This type of aberrations was significantly higher in the smoking subgroup than in the non-smoking subgroup of the clean-up workers. The fact of an increased level of unstable chromosomal aberrations in a remote period after irradiation allows us to suppose that other pathways of genomic burden may exist in addition to straight radiation action at the time of irradiation. Introduction Chromosome damage induced in human lymphocytes is often considered a sensitive indicator of radiation exposure [1-3]. An increased level of structural chromosomal aberrations in the clean-up workers soon after the Chernobyl accident has been reported [4,5]. It is known that the frequency of radiation markers (dicentric and ring chromosomes) decreases in time [6,7]. So, it is expected that the frequency of chromosomal aberrations (CA) in the clean-up workers, who suffered from low doses of radiation, would become as low as the control level some years after the accident. However, increased rate of chromosomal aberrations in the clean-up workers was demonstrated 4-6 years after the Chernobyl accident [8-11]. A follow-up study of Chernobyl clean-up workers has been carried out at All-Russian Centre of Emergency and Radiation Medicine Emercom of Russia (ARCERM) since 1992 in order to assess the consequences of low doses of ionising radiation on their health. Cytogenetical investigation was carried out simultaneously with clinical examination. The goal of this paper is to present the results of the follow-up study of cytogenetical damage in the peripheral blood lymphocytes from the clean-up workers in a remote period (6-12 years) after the Chernobyl accident. Materials and methods A cytogenetic study was carried out on 359 clean-up workers who worked at the Chernobyl station in 1986-1989. The investigation was performed 6-12 years after irradiation. 281 persons had official dose of irradiation, estimated by dosimetric service at Chernobyl. Most of them received up to 25 cGy, but 30 persons received from 25.1 cGy to 100 cGy. Thus, the mean dose of irradiation for clean-up workers who

Chromosomal aberrations in somatic cells (circulating lymphocytes) have been investigated in a remote period in different groups of people who suffered from radiation accidents. The chromosomal radiation markers were found even decades after irradiation. The question about the necessity of registration of non-classical mutagenic effects after human irradiation is raised.