Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Chernobyl”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 685 records · Page 38Linked to original sources
PubMed2002

DNA damage repair in bladder urothelium after the Chernobyl accident in Ukraine.

PURPOSE: We determined whether base and nucleotide excision repair is activated in bladder urothelium by chronic persistent low doses of ionizing radiation in male patients with benign prostate hyperplasia and females with chronic cystitis living more than 15 years in Cs contaminated areas after the Chernobyl accident in Ukraine. MATERIALS AND METHODS: Bladder urothelial biopsies from 204 patients were subjected to histological examination and biopsies from 35 were subjected to immunohistochemical study of 8-hydroxy-2'deoxyguanosine, 8-oxoguanine-DNA-glycosylase, apurinic/apyrimidinic endonuclease and xeroderma pigmentosum A endonuclease. RESULTS: Chronic proliferative atypical cystitis with multiple foci of dysplasia and carcinoma in situ were observed in 139 (89%) and in 91 (58%) of 156 group 1 patients from radio contaminated areas, respectively, as well as 10 small transitional cell carcinomas. Chronic cystitis with areas of dysplasia was detected in 9 of 48 patients (19%) in control group 2 from clean (without radio contamination) areas of Ukraine. Greatly elevated levels of 8-hydroxy-2'deoxyguanosine, 8-oxoguanine-DNA-glycosylase, apurinic/apyrimidinic endonuclease and xeroderma pigmentosum A were evident in the urothelium in group 1, accompanied by increased Cs in the urine. CONCLUSIONS: These findings support the hypothesis that significant activation of DNA damage repair (base and nucleotide excision repair) is induced by the oxidative stress generated by long-term low doses of ionizing radiation. The levels of DNA oxidative adducts pointing to mutagenic and carcinogenic potential were in line with the histopathologically diagnosed urothelial lesions.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2003

Extremely complex pattern of microsatellite mutation in the germline of wheat exposed to the post-Chernobyl radioactive contamination.

The molecular structure of rare variants at 13 microsatellite loci found in a population of wheat plants grown for one generation in the heavily contaminated 30 km exclusion zone around the Chernobyl Nuclear Power Plant and in a control population was compared. Evidence for rare alterations (variants) was obtained for all 13 loci, including gain and loss of repeats, as well as the complete loss of microsatellite bands. The ratio between gains and losses among variants in the control group was similar to that in the exposed group. Sequencing of variants at six microsatellite loci found in the exposed population revealed extremely complex pattern of germline mutations, including complete deletions of loci, a bias towards mutations with gains and losses of multiple repeat units, and relatively frequent insertions of DNA of unknown origin. The occurrence of large deletions at two loci may be attributed to direct and inverted repeats sequences located just upstream and downstream of the array. The results of our study also suggest that the majority of mutations within the studied wheat microsatellite loci are represented by gains and losses of multiple repeat units, implying that a simple model of replication slippage cannot account for mutation events at these loci. Our data also support the conclusion that the spectra of spontaneous and radiation-induced mutation in wheat may be similar.

Base Sequence↗
PubMed2003

Genome hypermethylation in Pinus silvestris of Chernobyl--a mechanism for radiation adaptation?

Adaptation is a complex process by which populations of organisms respond to long-term environmental stresses by permanent genetic change. Here we present data from the natural "open-field" radiation adaptation experiment after the Chernobyl accident and provide the first evidence of the involvement of epigenetic changes in adaptation of a eukaryote-Scots pine (Pinus silvestris), to chronic radiation exposure. We have evaluated global genome methylation of control and radiation-exposed pine trees using a method based on cleavage by a methylation-sensitive HpaII restriction endonuclease that leaves a 5' guanine overhang and subsequent single nucleotide extension with labeled [3H] dCTP. We have found that genomic DNA of exposed pine trees was considerably hypermethylated. Moreover, hypermethylation appeared to be dependent upon the radiation dose absorbed by the trees. Such hypermethylation may be viewed as a defense strategy of plants that prevents genome instability and reshuffling of the hereditary material, allowing survival in an extreme environment. Further studies are clearly needed to analyze in detail the involvement of DNA methylation and other epigenetic mechanisms in the complex process of radiation stress and adaptive response.

Acclimatization↗
PubMed1997

Increased level of chromosomal aberrations in lymphocytes of Chernobyl liquidators 6-10 years after the accident.

Chromosomal aberrations (CA) were used to investigate the level of cytogenetical damage in peripheral blood lymphocytes from the liquidators in a remote period (6-10 years) after the Chernobyl accident. There was a significantly higher frequency of chromosomal radiation markers (dicentrics and rings) in the peripheral lymphocytes of the liquidators than in the control subjects. No differences between these groups were demonstrated by the micronucleus (MN) test. Increased frequency of chromatid exchanges was associated with the smoking habits of the liquidators.

Adult↗
PubMed1997

Genetic disorders in house mouse germ cells after the Chernobyl catastrophe.

Genetic effects were studied in house mice caught from 1986 to 1994 in regions polluted by radionuclides as a result of the Chernobyl disaster. The dose rates of gamma-radiation on the soil surface ranged from 0.0002 to 2 mGy/h. The frequency of reciprocal translocations in mouse spermatocytes was relatively low, but increased with the dose rate. Embryo mortality was increased only in the progeny of male mice in males caught in 1987 in the area with maximal contamination. The frequency of mice heterozygous for recessive lethal mutations decreased with time after the accident.

Animals↗
PubMed1997

Further evidence for elevated human minisatellite mutation rate in Belarus eight years after the Chernobyl accident.

Analysis of germline mutation rate at human minisatellites among children born in areas of the Mogilev district of Belarus heavily polluted after the Chernobyl accident has been extended, both by recruiting more families from the affected region and by using five additional minisatellite probes, including multi-locus probe 33.6 and four hypervariable single-locus probes. These additional data confirmed a twofold higher mutation rate in exposed families compared with non-irradiated families from the United Kingdom. An elevated rate was seen at all three independent sets of minisatellites (detected separately by multi-locus probes 33.15, 33.6 and six single-locus probes), indicating a generalised increase in minisatellite germline mutation rate in the Belarus families. Within the Belarus cohort, mutation rate was significantly greater in families with higher parental radiation dose estimated for chronic external and internal exposure to caesium-137, consistent with radiation induction of germline mutation. The spectra of mutation seen in the unexposed and exposed families were indistinguishable, suggesting that increased mutation observed over multiple loci arises indirectly by some mechanism that enhances spontaneous minisatellite mutation.

Adult↗
PubMed1999

Total gene deletions and mutant frequency of the HPRT gene as indicators of radiation exposure in Chernobyl liquidators.

This study was conducted to determine the utility of deletion spectrum and mutant frequency (MF) of the hypoxanthine phosphoribosyl transferase gene (HPRT) as indicators of radiation exposure in Russian Liquidators who served in 1986 or 1987 in the clean up effort following the nuclear power plant accident at Chernobyl. HPRT MF was determined using the cloning assay for 117 Russian Controls and 122 Liquidators whose blood samples were obtained between 1991 and 1998. Only subjects from whom mutants were obtained for deletion analysis are included. Multiplex PCR analysis was performed on cell extracts of 1080 thioguanine resistant clones from Controls and 944 clones from Liquidators. Although the deletion spectra of Liquidators and Controls were similar overall, the Liquidator deletion spectrum was heterogeneous over time. Most notable, the proportion of total gene deletions was higher in 1991-1992 Liquidators than in Russian Controls (chi 2 = 10.5, p = 0.001) and in 1993-1994 Liquidators (chi 2 = 8.3, p = 0.004), and was marginally elevated relative to 1995-1996 Liquidators (chi 2 = 3.3, p = 0.07). This type of mutations has been highly associated with radiation exposure. Total gene deletions were not increased after 1992. Band shift mutations were also increased in the 1991-1992 Liquidators but were associated with increased MF of both Liquidators and Controls (p = 0.009), not with increased MF in 1991-1992 Liquidators (p = 0.7), and hence are not believed to be associated with radiation exposure. Regression analysis demonstrated that relative to Russian Controls HPRT MF was elevated in Liquidators overall when adjusted for age and smoking status (37%, p = 0.0001), and also was elevated in Liquidators sampled in 1991-1992 (72%, p = 0.0076), 1993-1994 (22%, p = 0.037), and 1995-1996 (62%, p = 0.0001). In summary, HPRT MF was found to be the more sensitive and persistent indicator of radiation exposure, but the specificity of total gene deletions led to detection of probable heterogeneity of radiation exposure within the exposed population.

Adult↗
PubMed1996

Modelling the Chernobyl radioactive fallout (I): A fractal approach in northern Italy.

This paper deals with the 137Cs airborne radioactive concentration measured in Northern Italy after the Chernobyl accident. We devised a fractal model to aid in describing the space-time distribution of radioactivity. The model is based on the Fractal Sum of Pulses theory, involving additive stochastic processes. We use, as input source of information, the parametrization of the time trend of radioactive concentration in a few Italian Provinces we calculated in previous work. The results look promising, since realistic scenarios of environmental pollution are produced.

Air Pollutants, Radioactive↗
PubMed1996

Modelling the Chernobyl radioactive fallout (II): A multifractal approach in some European countries.

This paper deals with the 137Cs cumulative soil deposition measured in some European Countries after the Chernobyl accident. We devised a multifractal model to aid in describing the spatial distribution of radioactivity. The model is based the Fractal Sum of Pulses theory, involving additive stochastic processes. We use, as input source of information, the available data of radioactive deposition measured in some European Countries. The results look promising, since realistic scenarios of environmental pollution are produced.

Air Pollutants, Radioactive↗
PubMed2003

Testing of a foodchain model using Chernobyl 137Cs fallout data and considering the effect of countermeasures.

Chernobyl 137Cs fallout data obtained during the period 1986-1996 from the most contaminated area in Russia were used within the IAEA BIOMASS programme to test the reliability of radiological assessment models. This model-testing scenario included information and data on countermeasures that were applied in the test area after the accident. This paper presents the predictions of the terrestrial foodchain model SPADE that was used in this model-testing exercise. SPADE predictions compared reasonably well with test data except for pigs and wild berries where differences were up to a factor of 50 and 200, respectively. Estimated intake of 137Cs and ingestion dose by adult men and women living in the test area compared favourably with the test data. Overall, SPADE proved to be capable of simulating agricultural countermeasures and their effectiveness. Modelling of countermeasures was found to be a complex process with large uncertainties regarding their 'real' implementation and effectiveness. The lessons learned from this exercise will be valuable in making future dose assessments/reconstructions involving countermeasures with improved results.

Adult↗
PubMed1996

Instrumental neutron activation analysis of essential and toxic elements in child and adolescent diets in the Chernobyl disaster territories of the Kaluga Region.

The main etiologic factor of various diseases, syndromes and pathologic conditions is an excess, deficiency or imbalance of trace element intake into the human body. Children seem to be the most sensitive to each change of trace element homeostasis. An inadequate essential trace element intake may result in an undesirable consequence that can apparently multiply against a background of additional unfavourable environmental influence such as high levels of radiation, organic and inorganic toxins, etc. Thus, the quality control of children's diets assumes urgent importance within the regions covered by the Chernobyl disaster. Instrumental neutron activation analysis was used to estimate contents of Ag, Br, Ca, Cl, Co, Cr, Cs, Fe, Hg, K, Mg, Mn, Na, Rb, Sb, Sc, Se, Sr, and Zn in the diets of children and adolescents. Diets were chosen from day care centre, boarding school and technical college cafeterias situated within the south and south west territories of the Kaluga Region, where radionuclide contamination ranges up to 15 Ci/km2. Ca and Zn deficiencies were found in the diets of children and adolescents aged 7-18. The Ca intake is only 212 mg/day, 5 times lower than that in developed countries. The Zn intake is 6.8 mg/day, 2 times lower than the level recommended by the WHO.

Adolescent↗
PubMed1997

Dynamics of 137Cs in the forests of the 30-km zone around the Chernobyl nuclear power plant.

Dynamics of the 137Cs content in the components of the forests in the 30-km zone around the Chernobyl nuclear power plant (NPP) in 1986-1994 are associated mainly with such factors as the size of radioactive particles in the fallout, ecosystem humidification and soil type, tree age. The influence of particle size was especially noticeable between 1986-1987 and was displayed by low biological availability of radionuclides in the near part of the zone (within the 10-km radius circle around the NPP) in comparison with more distant regions (within the 30-km radius circle). Later, the expression of this influence decreased and transfer factor (the ratio of 137Cs content in overground phytomass to the soil contamination density) became approximately the same for all plots with similar ecological and fallout characteristics. Humidity of landscape and soil type determined the velocity of radionuclide vertical migration in the soil and 137Cs biological availability. These parameters were maximum for the hydromorphic soils of wet landscapes enriched in organic substance and poor clayey minerals. Differences of 137Cs accumulation in overground phytomass of trees caused by tree age are displayed in the higher 137Cs concentration in structural parts of young trees as compared with old ones.

Cesium Radioisotopes↗
PubMed1997

Sedimentation rates measurements in former channels of the upper Rhône river using Chernobyl 137Cs and 134Cs as tracers.

Former river channels are aquatic ecosystems with a different geomorphology generated by fluvial dynamics more or less linked to the main channel. They present different ecological successions to become terrestrial ecosystems and are thus supposed to have different sedimentation rates. The aim of this paper is to assess this sedimentation rate using radioactive tracer methodology commonly used in lake studies. Chernobyl impacts, expressed in 137Cs concentration and 137Cs/134Cs ratio, were determined in sediment cores. Sites (21) were sampled in the alluvial plain of the Upper Rhône River from 1989 to 1994. The contamination presented a high spatial heterogeneity. The maximum values encountered by site ranged between 34 and 541 Bq/kg of dry matter. The method generally gave good core profiles. Sedimentation rate ranged between 0.14 and 0.70 cm/year for the former meanders and between 0.14 and 2.86 cm/year for the braided channels. The sediment accumulation rates ranged from 0.03 to 0.25 g/cm2 per year and 0.03 to 2.26 g/cm2 per year, respectively. These values are similar to those found for Lake Geneva. The importance of the former channels in relation to the main channel is enhanced by the higher contamination and radionuclides retention. The sediment accumulation rate is related to the organic carbon content in the sediment. A comparison between two former channels with different productivity showed that the the allogenous driven system presents a high organic sediment accumulation rate with a low organic content in the sediment and inversely, a low organic sediment accumulation rate with a high organic carbon content was found for the autogenous drive system.

Carbon↗
PubMed1989

Early infant mortality in West Germany before and after Chernobyl.

Early infant mortality rates in West Germany were plotted for regions with different radioactive burdens following the Chernobyl nuclear reactor explosion in April, 1986. In all regions, the logarithms of the mortality rates fitted a linear model between 1975 and 1985, but from May, 1986, immediately after the accident, there was a striking deviation from the model in areas with greatest radioactive fallout.

Accidents↗
PubMed2001

Migration ability of radionuclides in soil-vegetation cover of Belarus after Chernobyl accident.

This article illustrates the experimental experience achieved in the research of the self-restoration of radioactive-contaminated natural ecosystems. The main directions of studies were: the content and geochemical stability of "hot" particles in radioactive fallout from Chernobyl accident; the physicochemical forms (water-soluble, exchangeable, mobile and fixed) of Cs-137, Sr-90, Pu-239, 240 and Am-241 in the wide varieties of soils; the biological accessibility of radionuclides and their contents in soil pore solutions; and the dynamics and migration parameters of radionuclides vertical redistribution in different landscape conditions.

Americium↗
PubMed1996

Chromosome analysis of peripheral lymphocytes from persons exposed to radioactive fallout in Norway from the Chernobyl accident.

Chromosome analysis of peripheral lymphocytes from two Norwegian populations (44 reindeer herding South samis from Røros and Snåsa, 12 sheep farmers from Valdres) exposed to fallout from the Chernobyl accident were made. The doses from caesium through the years 1987-1991 were calculated based on whole-body measurements 134Cs and 137Cs giving a total cumulative mean internal dose of 5.54 mSv for the total group of 56 persons. Chromosome aberrations were within the normal range when compared with historical controls with the exception of dicentrics (0.3% per cell, which is a 10-fold increase) and rings (0.07% per cell). A dose-dependent increase in dicentrics and rings based on caesium exposure was not observed.

Air Pollutants, Radioactive↗
PubMed1996

Retrospective dose estimates in Estonian Chernobyl clean-up workers by means of FISH.

The present study deals with retrospective estimation of radiation doses, among Estonian Chernobyl clean-up workers, by means of scoring stable translocations using the FISH technique. All persons investigated in this study were sent to the area in 1986 and the majority of them were selected to be among those with the presumably highest exposure doses. In spite of the selection the estimated average dose is between 0.2-0.3 Gy, thus not clearly above the officially permitted dose level of 0.25 Gy. Due to unforseen conditions during transport of the blood samples, both the number of persons available for analysis and the number of metaphases available for scoring were substantially reduced. However, unless this selection is linked with the potential aberration frequency of the cells involved, no bias is expected.

Estonia↗