[The significance of the hypoxic factor in adaptation to the action of ionizing radiation as a result of the accident at the Chernobyl Atomic Electric Power Station]

Data are presented from cytochemical study of the neutrophil myeloperoxidase oxygen dependent enzymes and lymphocyte succinate dehydrogenase in the peripheral blood of 2169 persons subjected to follow-ups of many kinds, at year 7 and 8 after the Chernobyl accident. By comparison with early time periods, the process of normalization of the measured values has been found to be the case, with SDG returning to normal earlier than MPO. There was an increase in the number of individuals with reduced MPO activity and stable percentage of those demonstrating increased SDG activity (30-42% versus 12%). Significance of the adaptation process in the time course of changes of the values measured is discussed along with role of hypoxic factor in adaptation to the ionizing irradiation exposure after the Chernobyl accident.

[Gamma-aminobutyric acid content and activity of the enzyme synthesizing it in blood plasma of children exposed to ionizing radiation as a result of the accident at the Chernobyl nuclear power plant]

Marked individual fluctuations in blood levels of GABA and GDC revealed in 35 to 50% of adolescents exposed to ionizing radiation several years before indicate the presence of an imbalance in the GABA-ergic system. These children (with GABA-ergic system disturbances) represent a group at risk of developing remote effects of radiation exposure presenting as disturbed rhythms and terms of sexual maturation, of growth, thyroid and adrenal abnormalities, and they should be regularly checked up.

[Modelling the ecologic effect of accidents in gamma-treatment rooms]

The paper presents the procedure for evaluating the adverse radiation impact on the environment from the magnitude of the increased natural background while modelling emergencies on remote and intracavitary gamma-therapeutical apparatuses. It considers the accidents which result in full or partial failure of chamber protection with a full impaired source shield. The deleterious action of full chamber protection failure is displayed at about 12 km during accidents on remote gamma-apparatuses and at approximately 1,100 m during those on intracavitary equipment. In case of partially impaired chamber protection one should take into account the final dimensions of the source and the permeability of a chamber shield.

[Protein phosphorylation and activity of insulin and epidermal growth factor receptors in liver plasma membranes of rats kept in the zone of the accident at the Chernobyl nuclear power station]

Disruption in transfer of regulatory signal from insulin and EGF receptors in liver plasma membrane of rats, their 3 generation being kept in the Chernobyl accident 30-km zone has been found. As in case with imbalance in hormone binding and receptor phosphorylation of insulin receptors in experimental diabetes mellitus, an increasing of insulin and EGF binding by appropriate receptors with simultaneous decrease of its protein kinase activity after ligand binding was shown in rats chronically irradiated in the 30-km accident zone.

[Analysis of recessive sex-linked lethal mutations in genotypically different strains of Drosophila melanogaster MS and w, exposed in the 5-kilometer zone of the accident at the Chernobyl nuclear reactor]

The frequency of induced and spontaneous recessive sex-linked lethal mutations (RSLLM) in Drosophila melanogaster strains w and ms was estimated after their chronic irradiation in the five-kilometer zone of the Chernobyl' meltdown. The mutagenic effect of relatively low radiation doses was analyzed. In an experiment conducted in 1990, a significant increase in the RSLLM frequency was recorded, while, in 1991, no significant difference between the experiment and control was found.

[Medical and biological evaluation of new food products for children exposed to excessive radiation]

Nutritive value and protective efficiency of new foodstuffs for children were studied. Addition to the nutrition of sodium alginate and egg-shell powder renders it prophylactic properties under conditions of cesium-137 intake.

Contaminated casualties: are we prepared to receive them?

The NHS's reception of casualties contaminated by radiation is reviewed. The findings suggest that training, facilities and personal protection for hospital staff are inadequate.

[Enterosorption and therapeutic plasmapheresis in the intensive therapy of patients with acute leukemia and of persons who were victims of the accident at the Chernobyl Atomic Electric Power Station]

The paper reports on the preliminary experience of treatment of those patients having been the victims to the reactor accident at the Chernobyl NPP as well as of those with acute and chronic leukoses, having received courses of modern cytostatic therapy. The patients were exposed to therapeutic plasmapheresis and enterosorption as part of a complex conventional treatment programme. The conclusion the authors have come to is as follows: enterosorption strikingly reduces manifestations of "cytostatic disease"; the use of plasmapheresis in those persons having been previously exposed to small dose chronic radiation, makes for improvement of clinical and laboratory values but further studies are warranted to determine indications for therapeutic plasmapheresis.

[The nondrug treatment of patients with autonomic vascular dystonia subjected to ionizing radiation exposure as a result of the accident at the Chernobyl Atomic Electric Power Station]

The suggested mode of treatment combines the intravascular laser-light irradiation of blood with the visual analyzer exposure to light the brightness of which changes evenly and rhythmically with a frequency of 7-8 vibrations per minute (0.13 Hz). The combined use of the aforementioned exposures is justified due to the fact that exposure to both ionizing radiation and psychogenic factors play an important role in the pathogenesis of vegetovascular dystonia developing in the liquidators of the Chernobyl Atomic Power Plant breakdown. Change of lighting makes for the evolution of the inhibitory process in the cortex, has a sedative effect, attenuates the influence of psychotraumatizing factors. Intravascular laser-light irradiation of blood has a beneficial effect upon the organism's reactivity and immune system. Under the influence of the therapy adopted, all patients in present series (n = 67)--liquidators of the Chernobyl APP breakdown, suffering from VVD, demonstrated beneficial shifts both in the vegetovascular reactions and immune status, as evidenced by the analysis of the results of the presented mode of treatment in this patient population.

[The effect of environmental factors on the concentration of tumor markers in the blood serum and on the indices characterizing thyroid function]

Combined versus separate exposure of male organism to cesium-137 and chemical agents results in a more pronounced hyperferritinemia in the former case. In female chemists the ferritin level is dependent to a considerable extent on the menstrual cycle showing a tendency for the iron-containing protein level to decrease because of the action of a number of chemical agents. The rise of the level of cancer embryonic antigen is more readily seen in persons with high levels of cesium-137. Concentrations of carbohydrate antigen (CA-125) and mucin-like antigen are appreciably higher in female chemists incorporating cesium-137, and in those within the 30-km radius of the ChNPP. The level of thyroglobulin was raised in the chemists having a background incorporation of cesium, the liquidators of the aftermaths, and particularly in those happened to be in the 30-km zone. Each of the unfavourable factors taken separately (chemical agent or cesium-137) had lesser effect on the degree of elevation of TG content and hormone-forming function of the thyroid gland. An additional information has been obtained concerning the risk groups, which, however, serves as an indirect measure of carcinogenic effect various environmental factors exert on the organism.

[The use of wild animals in radioecological monitoring]

Radionuclide content in muscular and osseous tissues of elks and wild boars was determined by means of spectrum analysis. The radioactive caesium accumulation dynamics in muscular tissues of elks and wild boars from 1986 till 1992 years is presented.

[Osteopenic syndrome in liquidators of the aftereffects of the accident at the Chernobyl power plant]

Bone system was examined in 112 liquidators; in 71 of these osseous tissue density was studied by osseous densitometer using bienergetic x-ray absorptiometry and in 45 x-ray examinations, analyses of biochemical and hormonal parameters were carried out. Spinal painful syndrome was detected in 61 to 82% of the examinees. For analysis of densitometric and x-ray parameters the liquidators were divided into 2 groups: group 1 included those who worked at the power plant in 1986 (55%) and group 2 were those who worked there in 1987-1989. Radiation doses in group 1 reliably surpassed those in group 2 (p < 0.001). Bone mineral density in the lumbar vertebrae was significantly lower in group 1 as against group 2 and lower in both groups vs. controls. More than 5% osseous mineral loss was revealed in 73% of group 1 liquidators and in 43% of group 2 ones. Analysis of spinal roentgenograms in 45 liquidators showed a high incidence of negligible and moderately expressed osteoporosis without compression fractures of vertebral bodies: osteopenia signs were found in 87% of group 1 examinees complaining of pain in the spine and in 73% of group 2 examinees; signs of osteochondrosis and spondylosis were detected in 40% of group 1 and in 47% of group 2 subjects. Hence, a higher incidence of osteopenia in liquidators, more manifest condition and its higher detection rate in subjects exposed to higher radiation doses indicate a certain contribution of radiation factor to the development of the osteopenia syndrome in liquidators.

[Experimental study of long-term effects of irradiation on various indices of homeostasis]

Following radiation damage from LD50-LD97, changes in blood, immune and endocrine parameters were revealed and followed up in dogs at the time of late effects development, 3-18 months after exposure. The changes result from post-radiation immunodeficiency and resemble those observed in residents of radioactive contaminated areas or in men participated in Chernobyl accident amelioration.

[Radiosensitivity of erythropoietic stem cells (from the data on the aftereffects of the accident at the Chernobyl Atomic Electric Power Station]

The radiosensibility of erythropoietic tissue cells was estimated on the basis of analysis of erythrocyte and reticulocyte quantity changes in peripheral blood of the victims of the disaster on the Chernobyl NPP. The radiosensibility of blood cells was evaluated in accordance with their maturity (committed, committed-and-maturing and maturing pools). The population of erythropoietic tissue cells can be divided into two groups on the criterion of their radiosensibility. The first group demonstrates the highest level of radiosensibility varying from 0.5 to 1.73 Gy (n = 1). It includes the cells from primarily committed to basophilic normoblasts. The other group consisting of polychromatophils and oxyphils is more radioresistent. Do of these groups corresponds to their maturity and ascends from 4.7 to 12.9 Gy.

[The stress mechanisms of mammalian adaptation to an elevated content of radionuclides in the environment]

Analysis of populations of rodents and their stability in radioactively contaminated territories (East Ural radioactive track and regions contaminated after the Chernobyl Nuclear Power Plant accident) suggests that non-specific stability due to the stress mechanisms plays an important role in adaptation of the animals to the life in these regions. According to the published data, the elevated radioresistance of animals in these regions appeared to be due to increased non-specific stability formed by the stress mechanisms.

[Structural and physicochemical characteristics of DNA from animal tissue subjected to chronic irradiation in the Chernobyl area]

The properties of animal DNAs exposed to prolonged irradiation in the Chernobyl zone, have been studied by the methods of viscometry, thermal denaturation, IR-spectroscopy, and electrophoresis. High content of low-molecular fractions have been observed in the preparations of DNA from liver and spleen, their quantities increasing with age and generation of animals. This effect is especially strong in DNA from liver. Low-molecular fraction of DNA is shown to be enriched with G-C pairs and to consist of the following four fractions: 1) approximately 500 base pairs (B.p.), 2) approximately 1.5 divided by 2 thousand B.p., 3) approximately 4 divided by 5 thousand B.p. and 4) a mixture of approximately 20 thousand B.p. fragments. Further, it has been observed that the DNA preparations from the tissues of experimental animals contain about ten times higher contents of Fe, Zn, Se and other elements as compared to the control preparations.

[Cytogenetic analysis of first two mitoses in the root meristem of stored for a prolonged time period Crepis tectorum seeds subjected to chronic irradiation in the 30-kilometer zone of the accident at the Chernobyl Atomic Power Plant]

Seeds of Crepis tectorum natural populations 1 and 3 subjected to chronic irradiation in 1986 during 4 months in 30-kilometers zone of Chernobyl were stored for 6 years in a laboratory. In 1993 a method of continuous germination of seeds in 0.01% colchicin solution was used and an analysis of chromosome aberrations in the first tetraploid cells was made as it was done in 1987 just after finishing of a dormant period of seeds. By extrapolation from the data obtained by studying cells of the second colchicine mitosis to the cells of the previous mitosis from which they derived it was shown that the frequency of chromatid type aberrations in the early dividing cells after 6 year storage remained at the level which was observed just after finishing of a dormant period. This fact supports our previous proposition that chromatid aberrations observed in early dividing cells were probably induced by the incorporated long term radioactive products during seed germination, but not during seed storage.

[Serum levels of thymus hormones and autoantibodies to the thymus epithelium in inhabitants of regions contaminated with radionuclides]

Increased level of serum thymic activity and normal serum concentration of alpha-1-thymosin were revealed in inhabitants of region polluted by radionuclides after Chernobyl accident (settlement Vyshkov, Bryansk region). In the same population the serum level of autoantibodies, reacting with thymic epithelial cell line was elevated. Similar but less prominent alterations were found in population of radiologically pure region (settlement Potchep). Revealed autoantibodies had mainly IgM isotype. The negative correlation exists between levels of autoantibodies and serum thymic activity. Sera of persons from the control group and one half of Vyshkov inhabitants reacted with thymic epithelial cells of both human and mouse origin; in other half of Vyshkov inhabitants species-specific autoantibodies were revealed. We propose that correlated increase of antithymic autoantibody level and decrease of serum thymic activity are the consequence and indicators of unfavorable ecological conditions; however the contribution of radiation factor to their induction can not be estimated on the basis of presented data.

[Epidemiologic registry of leukemia and other hemoblastoses in Briansk region as an instrument of investigation of consequences of the accident at the Chernobyl nuclear power plant]

Beginning from 1986, at Hematological Research Centre (HRC) epidemiological monitoring has been performed on hemoblastoses in Bryansky district, which suffered from the Chernobyl accident more than any other area of Russia. The collection of personal information is organized about each case of disease from all possible sources, diagnosis verification, computer control, storage and analysis of materials. A specialized Register of Blood diseases is created, including demographical and ecological files. Retrospective period of monitoring 1979-1985, afteraccident period-from 1986. In the register 2832 cases were accumulated of hemoblastoses up to 1993. Regions are selected for monitoring with high levels of contamination by 137Cs (15 Ci/sq.km and more), and area for comparison--the other 21 regions of the district. The comparison did not reveal substantial differences. Further epidemiological analysis must be performed. Taking into account dose loads, special studies are initiated.