Possibilities of using the protective activity of MIGI-K under conditions of radionuclide contamination

Experimental studies of mussel hydrolyzate MIGI-K show that this drug has the ability to increase the general and radiation resistance of the human body. Moreover, MIGI-K facilitates elimination of incorporated radionuclides from the body. A series of properties of this drug, in particular, the absence of toxicity or harmful side effects, makes it possible to apply MIGI-K as an adaptogen (a food supplement exhibiting therapeutic and preventive action and used to increase excretion of radionuclides from people who took part in the liquidation of the accident at the Chernobyl Nuclear Plant).     

Possibilities of using MIGI-K protective activity under conditions of radionuclide contamination

Experimental studies of the mussel hydrolyzate (MIGI-K) have shown that this preparation can enhance both general and radiation resistance of the organism. Moreover, MIGI-K promotes elimination of incorporated radionuclides from the organism. Some properties of this preparation, in particular, the absence of toxicity or harmful side effects, have made it possible to apply MIGI-K as an adaptogen, that is, a food supplement oftherapeutic and preventive action used to increase radionuclide excretion in the Chernobyl emergency clean-up workers.     

The melanoidin-containing preparation MIGI-K from mussels and its characteristics]

The physico-chemical properties of preparation MIGI-K from mussels are given. Some characteristics of melanoidin fractions of MIGI-K are presented, their similarity to standard melanoidin is revealed. The given data on biological activity of the preparation permit to consider MIGI-K as immunomodulator.     

Radiation reactions and the possibilities for their modification in rats exposed in the area of the Chernobyl Atomic Electric Power Station]

A study was made of some embryological, hematological, cytogenetic and biochemical characteristics in Wistar rats exposed within the Chernobyl NPP zone over a period of 30 days (the average radiation background level, 75, and at the soil surface, 115 mR/h; a cumulative dose, 57 rad/30 days, and for pregnant rats, 36 rad/20 days). The quantity of chromosome aberrations in bone marrow metaphases and the embryonal death rate were invariable; some cases of teratogenesis were, however, observed. The total number of karyocytes in the brain and the leukocyte content in the peripheral blood sometimes decreased. The changes in certain characteristics (such as the content of endogenous amines and thiols in the liver and spleen) of the endogenous radioresistance background (ERB) and the normalization of the ERB by the radioprotective agent MIGI-K were found.     

Electron microscopy and ultracytochemistry of lymphocytes containing Gall bodies in the blood of patients with diabetes mellitus, Hodgkin disease and clean-up workers of the Chernobyl Atomic Electric Plant accident

Submicroscopic and ultracytochemical changes in lymphocytes containing Gall body complex in the cytoplasm, have been studied in the blood of patients with type 1 and 2 diabetes mellitus, Hodgkin disease, and clean-up workers of the Chernobyl accident. It has been shown that each pathological state was characterized by specific changes in the ultrastructure of Gall body complex, that pointed out its important role in the function of this type of lymphocytes and may be used as an additional cytological criterion in the estimation of T-immunity status.     

Monte-Carlo prediction of changes in areas of west Cumbria requiring restrictions on sheep following the Chernobyl accident

Following the 1986 Chernobyl accident radiocaesium levels in sheep meat in some upland areas of the United Kingdom were above the national intervention limit. West Cumbria was one of these areas and restrictions are currently still in place. In addition to deposition from the Chernobyl accident, Cumbria has been subject to radiocaesium deposition from atmospheric nuclear weapons tests, the 1957 Windscale accident and routine releases from the Sellafield nuclear reprocessing plant. A Monte-Carlo approach has been used to try to predict areas in west Cumbria where radiocaesium activity concentrations in lamb meat would require the imposition of restrictions at different times after the Chernobyl accident. The approach models the transfer of radiocaesium from soil to vegetation, based upon soil organic matter, and from vegetation to lamb meat. Spatial inputs are soil organic matter and total post-Chernobyl (137)Cs and (134)Cs deposition; a ratio of Chernobyl (137)Cs to (134)Cs deposition has been used to differentiate Chernobyl and pre-Chernobyl (137)Cs deposition. Comparisons of predicted radiocaesium transfer from soil-vegetation and the spatial variation in lamb (137)Cs activity concentrations are good and predicted restricted areas with time after Chernobyl compare well to the restricted areas set by UK government. We predict that restrictions may be required until 2024 and that in some areas the contribution of pre-Chernobyl (137)Cs to predicted lamb radiocaesium activity concentrations is significant, such that restrictions may only have been required until 1994 as a consequence of Chernobyl radiocaesium deposition alone. This work represents a novel implementation of a spatial radioecological model using a Monte-Carlo approach.     

An assessment of the permissible level of a mixture of radionuclides from the Chernobyl fallout in human lungs]

The permissible level of a radionuclide mixture, resulted from the Chernobyl burst, in the human being lungs was determined for two kinds of compounds: absolutely insoluble compounds and soluble compounds in the state of equilibrium. For this purpose the data were used concerning the radionuclide composition and aerosol disperse in lower atmosphere which were obtained by the Department for Dosimetric Control (NPO "Pripiat'"). The results of measurements of 137Cs content taken by the use of human radiation spectrometer (HRS) needed an adequate estimation: low level of 137Cs in the human lungs and body within the Chernobyl NPP, zone does not guarantee radiation security. The notion "permissible content" and the possibility of using thereof in the individual dosimetric control are discussed.     

Molecular aspects of plant adaptation to life in the Chernobyl zone

With each passing year since the Chernobyl accident of 1986, more questions arise about the potential for organisms to adapt to radiation exposure. Often this is thought to be attributed to somatic and germline mutation rates in various organisms. We analyzed the adaptability of native Arabidopsis plants collected from areas with different levels of contamination around the Chernobyl nuclear power plant from 1986 to 1992. Notably, progeny of Chernobyl plants resisted higher concentrations of the mutagens Rose Bengal and methyl methane sulfonate. We analyzed the possible molecular mechanisms of their resistance to mutagens and found a more than 10-fold lower frequency of extrachromosomal homologous recombination, significant differences in the expression of radical scavenging (CAT1 and FSD3) and DNA-repair (RAD1 and RAD51-like) genes upon exposure to mutagens (Rose Bengal and x-rays), and a higher level of global genome methylation. This data suggests that adaptation to ionizing radiation is a complex process involving epigenetic regulation of gene expression and genome stabilization that improves plants' resistance to environmental mutagens.     

Medical protection during radiation accidents: some results and lessons of the Chernobyl accident

Actions of medical radiation protection of liquidators of consequences of on Chernobyl atomic power station accident are analysed. It is shown, that during the early period of the accident medical protection of liquidators was provided by administration of radioprotectors, means of prophylaxis: of radioactive iodine incorporation and agent for preventing psychological and emotional stress. When carrying out decontamination and regenerative works, preparations which action is caused by increase of nonspecific resistance of an organism were applied. The lessons taken from the results of the Chernobyl accident, have allowed one to improve the system of medical protection and to introduce in practice new highly effective radioprotective agents.     

Cambial history of Scots pine trees (Pinus Sylvestris) prior and after the Chernobyl accident as encoded in the xylem

Studies were carried out on wood samples collected in October 1997 from breast height of Scots pine trees (Pinus sylvestris) from site located 5 km south from the Chernobyl nuclear power plant. The radioactive contamination at the site was 3.7x10(5) kBq m(-2). These samples of secondary wood were used as an archive of information about the dynamics of a meristematic tissue cambium affected by ionising radiation from the Chernobyl reactor accident. The results show that frequency of the cambial cells events like anticlinal divisions, intrusive growth and cells elimination, was after the Chernobyl accident, about three times higher in comparison to preceding years. The most interesting finding was that after irradiation the length of tracheids increased. This increase is interpreted as an effect of intracambial competition among cells in the initial layer.     

Genomic damage in children accidentally exposed to ionizing radiation: a review of the literature

During the last decade, our knowledge of the mechanisms by which children respond to exposures to physical and chemical agents present in the environment, has significantly increased. Results of recent projects and programmes focused on children's health underline a specific vulnerability of children to environmental genotoxicants. Environmental research on children predominantly investigates the health effects of air pollution while effects from radiation exposure deserve more attention. The main sources of knowledge on genome damage of children exposed to radiation are studies performed after the Chernobyl nuclear plant accident in 1986. The present review presents and discusses data collected from papers analyzing genome damage in children environmentally exposed to ionizing radiation. Overall, the evidence from the studies conducted following the Chernobyl accident, nuclear tests, environmental radiation pollution and indoor accidental contamination reveals consistently increased chromosome aberration and micronuclei frequency in exposed than in referent children. Future research in this area should be focused on studies providing information on: (a) effects on children caused by low doses of radiation; (b) effects on children from combined exposure to low doses of radiation and chemical agents from food, water and air; and (c) specific effects from exposure during early childhood (radioisotopes from water, radon in homes). Special consideration should also be given to a possible impact of a radiochemical environment to the development of an adaptive response for genomic damage. Interactive databases should be developed to provide integration of cytogenetic data, childhood cancer registry data and information on environmental contamination. The overall aim is to introduce timely and efficient preventive measures, by means of a better knowledge of the early and delayed health effects in children resulting from radiation exposure.     

Results of cytogenetic studies of the consequences of the Chernobyl accident

The selected results of the cytogenetic studies of the Chernobyl accident consequences were summarised. The chromosomal aberrations were used as a method of biodosimetry for a dose assessment for victims during the initial period after the Chernobyl accident. A good correlation between doses calculated based on chromosomal aberrations (dicentrics) and severity of acute radiation syndrome observed in clinic was found. The biodosimetry based on conventional cytogenetic technique (dicentrics) has been unsuccessful for various groups (rehabilitation workers, evacuees, inhabitants of contaminated areas) sampled long time after the Chernobyl accident. The possible reasons of the failure are analysed. The original results of multiaberration cell yield observed in different cohorts of the Chernobyl victims are presented. The problems related to the phenomena are discussed.     

The effect of gamma-radiation and desiccation on the viability of the soil bacteria isolated from the alienated zone around the Chernobyl Nuclear Power Plant

Methylobacterium extorquens, M. mesophilicum, and Bacillus subtilis strains were found to be resistant to gamma-radiation, irrespective of whether they were isolated from the alienated zone around the Chernobyl Nuclear Power Plant or outside this zone. The LD90 of Methylobacterium and B. subtilis strains with respect to gamma-radiation was 2.0-3.4 and 3.7-4.4 kGy, respectively, whereas their LD99.99 values were 4.5-6.9 and more than 10 kGy, respectively. The high threshold levels of gamma-radiation for Methylobacterium and B. subtilis imply the efficient functioning of DNA repair systems in these bacteria. Unlike Bacillus polymyxa cells, the cells of M. extorquens, M. mesophilicum, and B. subtilis were also resistant to desiccation. Pseudomonas sp., Nocardia sp., and nocardioform actinomycetes were sensitive to both gamma-radiation and desiccation. Similar results were obtained when the bacteria studied were exposed to hydrogen peroxide and ultraviolet radiation. The results obtained indicate that the bacteria that are resistant to gamma-radiation are also resistant to desiccation, UV radiation, and hydrogen peroxide. The possibility of using simple laboratory tests (such as the determination of bacterial resistance to UV light and desiccation) for the evaluation of bacterial resistance to gamma-radiation is discussed.     

The biological effects in animals in relation to the accident at the Chernobyl Atomic Electric Power Station. 7. The content of lipid peroxidation products and free fatty acids and the catalase activity in a number of organs and tissues of rats]

The content of malonic dialdehyde, dienic conjugates and free fatty acids, and catalase activity were determined in some organs and tissues of chronically irradiated rats. Certain regularities were found in lipid metabolism changes. The MIGI-K preparation was shown to normalize some indices under study.     

Strontium fallout from Chernobyl and perinatal mortality in Ukraine and Belarus

Perinatal mortality rates in the regions of Ukraine and Belarus surrounding the Chernobyl site increased in 1987, the year following the Chernobyl accident. The same year, increases of perinatal mortality were also observed in Germany and Poland, and the effect can be associated with the caesium burden in pregnant women. After 1989, there is an unexpected second rise of perinatal mortality in Belarus and Ukraine. This increase is shown to correlate with the strontium content in pregnant women. The findings parallel an increase of perinatal mortality in Germany following the atmospheric bomb tests in the 1950's and 1960's. While the effect from caesium is essentially limited to 1987, the effect from strontium persists until the end of the study period in 1998. The cumulative effect from strontium around Chernobyl outweighs the effect from caesium by at least a factor of 10. This is contrary to the assertion that the caesium content in the Chernobyl fallout was more than 10-times greater than the strontium content. Thus, the dose factor presently used seems to severely underestimate the effect of strontium on perinatal mortality.     

Chromosome aberrations of clonal origin in irradiated and unexposed individuals: assessment and implications.

Chromosome painting has proven useful for the detection of chromosomal rearrangements, although the presence of cells containing clonal aberrations can have an effect on the outcome of cytogenetic analyses (e.g. aberration frequency and chromosomal distribution studies). Cells with clonal chromosomal changes have been found in studies of both radiation-exposed Chernobyl cleanup workers ("liquidators") and healthy unexposed human subjects. We have used a simple statistical method to aid in the identification of individuals from distinct Chernobyl radiation-exposed and unexposed control populations who may possess cells containing clonal rearrangements. A chi2 value determined from the observed number of aberrations and the expected number based on chromosome length that corresponds to a probability less than 0.005 appears to be an indicator of clonality. These selected individuals can be analyzed further for clonality, thereby sparing detailed examination of the entire population. Here we present an analysis of individuals possessing clonal aberrations to assess the influence of clonality on the results of cytogenetic studies. Our results show that the subtraction of clonal events from the chi2 calculation for the "outliers" results in nearly all of these values losing their statistically significant deviation from proportionality. These adjustments can also be made to prevent the overestimation of frequencies of chromosome aberrations for biodosimetry. The frequency of clonal aberrations appears to increase as a function of age in control subjects, whereas an age effect was not evident in Chernobyl liquidators. This suggests that spontaneous and radiation-induced clonal expansion are occurring in control subjects and liquidators, respectively.     

Long term effects of Chernobyl contamination on DNA repair function and plant resistance to different biotic and abiotic stress factors

Thirty years after the Chernobyl explosion we still lack information regarding the genetic effects of radionuclide contamination on the plant population. For example, are plants adapting to the low dose of chronic ionising irradiation and showing improved resistance to radiation damage? Are they coping with changing/increased pathogenicity of fungi and viruses in the Chernobyl exclusion (ChE) zone? Are plant populations rapidly accumulating mutational load and should we expect rapid micro-evolutionary changes in plants in the Chernobyl area? This review will try to summarise the current knowledge on these aspects of plant genetics and ecology and draw conclusions on the importance of further studies in the area around Chernobyl.     

Aerial contamination of agroecosystems following the accident at the Chernobyl Nuclear plant

The regularities of the aerial contamination of agricultural ecosystems are described in the early period after the Chernobyl NPP accident. The aerial contamination is shown to be caused by the development of the above-ground biomass of plants and fallout characteristics. A specific coefficient of primary retention varied between 0.46 and 1.2 m2 kg-1 for 137Cs. The first half-life period varies from 9.7 to 13.4 days. The second period varies from 46.2 to 52.2 days. It has been found that parameters of aerial contamination from the Chernobyl accident well correlate with the results of observation in the period of global fallout.