[Radiation-induced modification of human somatic cell chromosome sensitivity to the testing mutagenic exposure of bleomycin in vitro in lung cancer patients in delayed terms following Chernobyl accident].

By using modified "G2-bleomycin sensitivity assay" above background level of cytogenetic effect considered as a marker of hidden chromosome instability (HCI) has been investigated in 3 groups--liquidators of Chernobyl accident (occupational group 1), patients with lung cancer who denied conscious contact--with ionizing radiation (group of comparison), liquidators with lung cancer (occupational group 2). Significant interindividual variations of cytogenetic effects induced with bleomycin and the lack of positive correlation between background and above background frequencies of chromosome aberrations have been shown in all observed groups. It had been established that occupational group 2 was the most burdened group by expression of the above background cytogenetic effect and, accordingly, number of persons with HCI. The data obtained permit to suggest the existence of the association between radiation-induced increase of individual sensitivity to testing mutagenic exposure and the realization of cancer in persons exposed to ionizing radiation. The results show acceptability of "G2-bleomycin sensitivity assay" under the cytogenetic examination of irradiated contingents for determining HCI as one of informative markers of predisposition to oncopathology.

[Somatic chromosome mutagenesis in residents of Ukraine exposed to ionizing radiation in different periods after the Chernobyl accident].

The authors summarize results of 25-year selective cytogenetic monitoring of the priority groups in different periods after the Chernobyl accident. The increase in intensity of somatic chromosome mutagenesis in exposed individuals as a result of both targeted and non-targeted radiation-induced cytogenetic effects has been confirmed including delayed, transmissible, hidden chromosome instability and the bystander effect.

[The experience of FISH technique application for reconstruction of individual radiation doses in Chernobyl liquidators in the framework of Ukrainian-American project "Leukemia"].

The results of proper investigations received under the cytogenetic examination of 225 persons (control groups, Chernobyl liquidators exposed to different radiation doses, oncogematology patients) had been summarized and analyzed. The conclusion concerning possibilities and limitations of FISH technique usage for retrospective biodosimetry of human radiation exposure has been presented.

[The results of 14-year cytogenetic monitoring of priority follow-up groups of Chernobyl accident victims]. / Rezul'taty 14-letnego tsitogeneticheskogo monitoringa kontingentov prioritetnogo nabliudeniia, postradavshikh ot deistviia faktorov avarii na Chernobyl'skoi AES.

The paper presents the results of 14-year (1987-2000) random cytogenetic monitoring of the Ukraine's population exposed to radiation due to the Chernobyl Atomic Power Plant accident. Conventional, G-banding, and molecular (FISH-WCP) cytogenetic methods were used to examine groups of victims exposed to radiation of varying intensity (reconvalescents diagnosed as having acute radiation disease, liquidators, Chernobyl power plant staff, and persons who had lived in the radionuclide-polluted areas, etc.). The examinees from all groups were found to have a considerable increase in the incidence of chromosomal aberrations in the peripheral lymphocytes as compared to their spontaneous levels. There was an interindividual variability in the chromosomal aberrations under identical radiation conditions. It was ascertained that even small human doses of long-term ionizing radiation could induce specific chromosomal aberrations. The findings show that conventional cytogenetic monitoring, and particularly by applying FISH and WCP methods, is an good procedure for assessing the human cell genetic apparatuses after radiation.

[Frequency of stable chromosomal aberrations determined by FISH in 49 Chernobyl nuclear accident liquidators exposed to various doses of radiation]. / Chastota stabil'nykh khromosomnykh aberratsii ustanovlennaia s pomoshch'iu metoda FISH u 49 likvidatorov Chernobyl'skoi avarii s razlichnymi dozami oblucheniia.

FISH technique was tested on the 49 liquidators of the Chernobyl Accident. Groups were formed according to average group exposure doses and/or individual ones determined by the method of EPR. The essential variability of spontaneous and irradiation-induced frequencies of reciprocal translocations was observed. In groups with the lowest EPR-doses (below 25 cGy) the average cytogenetic dose was considerably higher then doses determined by EPR-method. The best coincidences between average in-group EPR- and FISH-doses were in the group with 25-50 cGy doses for "acute irradiation" model and in the group with 50-100 cGy and higher for "chronic irradiation" model.

[The cytogenetic effect in a group of settlers from a 30-kilometer area of right of way]. / Tsitogeneticheskii éffekt v gruppe samoselov iz 30-kilometrovoi zony otchuzhdeniia.

One of the critical human group of potential risk is the group of population from 30-km zone around the Chernobyl nuclear power plant. The cytogenetical examination of 12 persons (8 man, 4 woman, 30-60 years old) from 5 villages situated in north-west and south-east directions from the ChNPP in the frame of this zone was conducted. The data of the conventional analysis showed relatively low cytogenetic effects comparable with the effects in exposed people out of the zone (the mean level of unstable cytogenetic markers in different villages was 0.21-0.35 per 100 cells). The level of stable translocations in one case (woman, 59 years old) determined using FISH (16.62 per 100 cells for the whole genome) exceeded their spontaneous aged frequency and confirmed the high sensitivity of this method for the evaluation of real radiation exposure.

[The use of the FISH method for the cytogenetic examination of persons with a history of acute radiation sickness in connection with the accident at the Chernobyl Atomic Electric Power Station]. / Ispol'zovanie metoda FISH dlia tsitogeneticheskogo oblsedovaniia lits, perenesshikh ostruiu luchevuiu bolezn' v sviazi s avariei na Chernobyl'skoi AES.

We have performed conventional cytogenetics with group karyotyping and FISH analysis on metaphase-arrested lymphocyte cultured from 13 adults of 23 to 50 years. Twelve Chernobyl accident liquidators of 1986 year recovered from acute radiation sickness of the first (3 persons), second (7 persons) and third (2 persons) degree of severity; and one unexposed (control) person. A cocktail containing a balanced mix of directly-labeled by Spectrum orange whole-chromosome probes for human chromosomes 1,2 and 4 were used. Under the conventional staining the positive correlation between the frequency of chromosome type aberration (acentrics, dicentrics, centric rings, abnormal monocentrics) and the severity of irradiation was established even 10 years after radiation exposure. Under the FISH analysis the frequency of reciprocal translocation was in the range from 0.061 to 0.729 per cell which corresponded to doses of acute uniform irradiation from 0.8 till 3.48 Gy. The data obtained confirmed the validity of FISH as for quantifying stable chromosome aberrations in peripheral lymphocytes of irradiated persons as the high sensitivity of FISH for the retrospective dose evaluation in delayed terms after radiation exposure.

[The genetic effects in the somatic cells of persons working under chronic irradiation of different intensities after the accident at the Chernobyl Atomic Electric Power Station]. / Geneticheskie éffekty v somaticheskikh kletkakh lits, rabotaiushchikh v usloviiakh khronicheskogo oblucheniia raznoi intensivnosti posle avarii na Chernobyl'skoi AES.

A complex genetic study of two groups from of Chernobyl NPP personnel (from "Shelter" unit and 3rd Block) has been carried out using classical cytogenetic and GPA methods. The first group was the most vulnerable from the viewpoint of accumulated dose (exceeding 25 cGy for the moment of study). Positive correlation between individual and group frequencies of cytogenetic markers of irradiation (stable and unstable chromosomes aberrations) and NO mutations in the GPA locus was found.

[The dynamic course of the mutation process in human peripheral blood lymphocytes under conditions of exposure to low levels of ionizing radiation]. / Dinamika protekaniia mutatsionnogo protsessa v limfotsitakh perifericheskoi krovi cheloveka v usloviiakh postoiannogo vozdeistviia malykh urovnei ioniziruiushchei radiatsii.

In seven groups of children living in the areas contaminated by nuclides a significant cytogenetic effect has been detected. The degree of its expression (integral and specific markers) was similar and did not correlate with the density of contamination by radionuclides.

[The cytogenetic monitoring of the victims of the accident at the Chernobyl Atomic Electric Power Station]. / Tsitogeneticheskii monitoring lits, postradavshikh ot avarii na Chernobyl'skoi AES.

The results of the cytogenetic monitoring of population groups that are critical with respect to the intensity of irradiation exposure (liquidators of the accident, including those who suffered from acute atomic disease) or to sensitivity of cell genome to irradiation (children living in zones with radioactive contamination) indicate a significant increase in the frequency of both chromosomal aberrations and markers of the irradiation effect in each of the groups and correlate with the ecologic situation in the regions studied.

[The detection of multiaberrant lymphocytes in the cytogenetic examination of different groups of people in contact with mutagenic factors]. / Vyiavlenie mul'tiaberrantnykh limfotsitov pri tsitogeneticheskom obsledovanii razlichnykh grupp liudei, kontaktiruiushchikh s mutagennymi faktorami.

Data are presented on the frequency of multi-aberrant cells in lymphocytes gained during the period from 1967 to 1992 in some groups of the USSR inhabitants, who contacted with different environment mutagenesis. It is shown that the results of the study of 1500 men give a possibility to account some groups of multi-aberrant cells not to be artifacts and to be induced by some of the mutagens studied.

[Dimatif modification of the cytogenetic effect in the peripheral blood lymphocytes of children subjected to a constant low-intensity radiation exposure]. / Modifikatsiia dimatifom tsitogeneticheskogo éffekta v limfotsitakh perifericheskoi krovi detei, podvergaiushchikhsia postoiannomu radiatsionnomu vozdeistviiu maloi intensivnosti.

Primary results of cytogenetic monitoring of children living in regions of Ukraine contaminated after Chernobyl accident permit suggesting existence of radiation-induced modification of sensitivity of somatic cell chromosomes to mutagens. It may be supposed that interindividual and group difference in sensitivity of in vivo irradiated cells to additional induction of in vitro mutagen effect is explained not only by inherited properties, but also by preliminary irradiation.

[The cytogenetic effect in peripheral blood lymphocytes as an indicator of the effect on man of factors of the Chernobyl accident]. / Tsitogeneticheskii éffekt v limfotsitakh perifericheskoi krovi kak indikator deistviia na cheloveka faktorov Chernobyl'skoi avarii.

The data obtained confirm the possibility of both individual and population cytogenetic indication of the effect of low intensity radiation, exceeding the background level, and exhibit a positive correlation with the radio-ecological situation formed. The cytogenetic effect, that indicates the disturbance of the genome stability, might be considered as an indicator of a high probability of occurrence of pathologies, with a genetic component, in the subpopulations under study, compared to spontaneous level.

[Frequency of chromosome aberrations in peripheral blood lymphocytes of children living in regions with various radio-ecologic situations]. / Chastota khoromosomnykh aberratsii v limfotsitakh perifericheskoi krovi detei, prozhivaiushcheikh v raionakh s razlichnoi radioékologicheskoi obstanovkoi.

First results of cytogenetic monitoring of children, living in contaminated regions of the Ukraine show statistically significant increase in quantity of chromosome aberrations, that is positively correlated with environmental situation. The effect found shows that damage of genome stability must be accounted as an indicator of increased possibility of gene-based pathology in studied groups as compared to control.