Past exposure to densely ionizing radiation leaves a unique permanent signature in the genome.
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Speculation has long surrounded the question of whether past exposure to ionizing radiation leaves a unique permanent signature in the genome. Intrachromosomal rearrangements or deletions are produced much more efficiently by densely ionizing radiation than by chemical mutagens, x-rays, or endogenous aging processes. Until recently, such stable intrachromosomal aberrations have been very hard to detect, but a new chromosome band painting technique has made their detection practical. We report the detection and quantification of stable intrachromosomal aberrations in lymphocytes of healthy former nuclear-weapons workers who were exposed to plutonium many years ago. Even many years after occupational exposure, more than half the blood cells of the healthy plutonium workers contain large (>6 Mb) intrachromosomal rearrangements. The yield of these aberrations was highly correlated with plutonium dose to the bone marrow. The control groups contained very few such intrachromosomal aberrations. Quantification of this large-scale chromosomal damage in human populations exposed many years earlier will lead to new insights into the mechanisms and risks of cytogenetic damage. (+info)
Thyroid consequences of the Chernobyl nuclear power station accident on the Turkish population.
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OBJECTIVE: The Chernobyl accident caused widespread effects across Europe and huge areas were radiocontaminated. The major impact of the accident on human health was a sharp increase in childhood thyroid carcinoma and autoimmune thyroid diseases in exposed populations. The thyroidal effects of the Chernobyl accident have been investigated in most European countries, except Turkey. The aim of the current study was therefore to determine the thyroidal consequences of the Chernobyl nuclear power station accident in a selected Turkish population. DESIGN: This study was designed as a sectional, area study, between October 2000 and March 2001, in two different regions of Turkey. According to the data of the Turkish Atomic Energy Authority, the eastern part of the Black Sea region was the most radiocontaminated area in Turkey at the time of Chernobyl accident, while Middle Anatolia was not seriously affected. Thus, Rize city, which is located in the eastern Black Sea region, served as a study area, and 970 adolescents, living in this region, comprised our study group (group R). On the other hand, Beypazari, which is located in Middle Anatolia, was chosen as the control region, and 710 adolescents living in this location were enrolled into the study as controls (group B). METHODS: During the study, thyroid ultrasounds were performed in all subjects and thyroid volumes were calculated. World Health Organization and International Council for Control of Iodine Deficiency Disorders criteria were used for the determination of goiter. Thyroid fine-needle aspiration biopsy with ultrasound guidance was performed when a nodule was detected. Blood samples for thyroid function tests and thyroid autoantibodies, and urine samples for urinary iodine excretion were collected from all subjects. RESULTS: Thyroid function tests were similar in both groups, but thyroid volumes were found to be higher in group B (13.93+/-5.04 vs 17.66+/-5.58 ml; P<0.001). The prevalence of goiter was found to be 28.25% in group R and 61.95% in group B (P<0.001). Thyroid nodules were determined in 6.28% of subjects in group R and 4.22% of subjects in group B (P=0.065). No malignant lesions were found in either of the regions. Although the percentage of autoantibody-positive subjects did not differ between groups (21.25% in group R vs 18.72% in group B), the mean anti-thyroglobulin level was found to be higher in group R (63.25+/-378.60 vs 51.97+/-333.32 IU/ml; P<0.001) and the mean anti-thyroid peroxidase level was higher in group B (24.14+/-219.09 vs 48.82+/-568.50 IU/ml; P<0.001). The iodine status of the selected regions was found to be significantly different (median urinary iodine excretion was 131 microg/l in Rize and 54 microg/l in Beypazari). CONCLUSIONS: Although there was a slight increase in nodule prevalence and thyroid antibody-positive subjects in the study group, it is hard to conclude that Turkey was affected by the Chernobyl accident. These results, at least the significant differences with regard to the prevalence of goiters between groups, may reflect the different iodine status of the selected regions. (+info)
Neoendothelialization after peripheral blood stem cell transplantation in humans: a case report of a Tokaimura nuclear accident victim.
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OBJECTIVES: Neoendothelialization by circulating endothelial progenitor cells has been a topic of recent research. The extent and scale of this process in humans is not well understood. We examined the extent of neoendothelialization of the aorta and peripheral arteries in the case of a patient who underwent peripheral blood stem cell transplantation for acute radiation syndrome. METHODS: Human tissue samples from the aorta and peripheral arteries were obtained at autopsy. Endothelial cells were isolated, confirmed by von Willebrand factor immunostaining, and then subjected to fluorescent in situ hybridization analysis using X- and Y-chromosome specific probes to examine neoendothelialization by donor cells as possible in this case in which the donor and recipient were of different genders. RESULTS: The aorta showed almost 25% of all endothelial cells to be replaced by donor-origin endothelial cells. The peripheral arteries were also replaced but to a lesser extent. DISCUSSION: The present study provides evidence that peripheral blood is a source of endothelial progenitor cells in humans. Neoendothelialization of the aorta occurs to a significant extent under certain conditions suggesting the potential for exploitation of therapeutic neovascularization by transplantation of circulating endothelial progenitor cells. (+info)
Cancer in the offspring of radiation workers: an investigation of employment timing and a reanalysis using updated dose information.
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An earlier case-control study found no evidence of paternal preconceptional irradiation (PPI) as a cause of childhood leukaemia and non-Hodgkin's lymphoma (LNHL). Although fathers of children with LNHL were more likely to have been radiation workers, the risk was most marked in those with doses below the level of detection. The timing of paternal employment as a radiation worker has now been examined. The previously reported elevated risk of LNHL in the children of male radiation workers was limited to those whose fathers were still radiation workers at conception or whose employment also continued until diagnosis. Children whose fathers stopped radiation work prior to their conception were found to have no excess risk of LNHL. It was not possible to distinguish between the risks associated with paternal radiation work at conception and at the time of diagnosis. A reanalysis of the original study hypothesis incorporating updated dosimetric information gave similar results to those obtained previously. In particular, the risks of LNHL did not show an association with radiation doses received by the father before conception. It seems likely that the increased risk of LNHL among the children of male radiation workers is associated with an increased exposure to some infective agent consequent on high levels of population mixing. (+info)
Chronic Cs-137 incorporation in children's organs.
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In Belarus's Gomel region, which was heavily contaminated by fallout from the Chernobyl disaster, we have studied the evolution of the Cs-137 load in the organisms of the rural population, in particular children, since 1990. Children have a higher average burden of Cs-137 compared with that of adults living in the same community. We measured the Cs-137 levels in organs examined at autopsy. The highest accumulation of Cs-137 was found in the endocrine glands, in particular the thyroid, the adrenals and the pancreas. High levels were also found in the heart, the thymus and the spleen. (+info)
"Rogue" lymphocytes among Ukrainians not exposed to radioactive fall-out from the Chernobyl accident: the possible role of this phenomenon in oncogenesis, teratogenesis, and mutagenesis.
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Cultured lymphocytes exhibiting extreme cytogenetic damage (rogue cells) were observed in preparations from 8 of 24 individuals sampled in Krasilovka, a Ukrainian village receiving little or no increased radiation after the Chernobyl disaster, but were not observed in an additional 24 persons from two Russian towns in the more contaminated area. This observation cements the worldwide occurrence of these cells. The present data plus a review of the literature establish that rogue cells appear in brief bursts simultaneously in certain individuals of discrete populations. We suggest that the pattern is consistent with the action of a viral trigger that acts directly or indirectly--the latter possibly through the activation of latent chromosomal retroposons. If this phenomenon occurs in other tissues, it may have important implications for oncogenesis, teratogenesis, mutagenesis, and evolution. (+info)
Incidence of childhood leukaemia in the vicinity of nuclear sites in France, 1990-1998.
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Overall, 670 cases (O) of childhood leukaemia were diagnosed within 20 km of the 29 French nuclear installations between 1990 and 1998 compared to an expected number (E) of 729.09 cases (O/E=0.92, 95% confidence interval (CI)=[0.85-0.99]). Each of the four areas defined around the sites showed non significant deficits of cases (0-5 km: O=65, O/E=0.87, CI=[0.67-1.10]; 5-10 km: O=165, O/E=0.95, CI=[0.81-1.10]; 10-15 km: O=220, O/E=0.88, CI=[0.77-1.00]; 15-20 km: O=220, O/E=0.96, CI=[0.84-1.10]). There was no evidence of a trend in standardised incidence ratio with distance from the sites for all children or for any of the three age groups studied. Similar results were obtained when the start-up year of the electricity-generating nuclear sites and their electric nuclear power were taken into account. No evidence was found of a generally increased risk of childhood leukaemia around the 29 French nuclear sites under study during 1990-1998. (+info)
Learning difficulties in children born to male UK nuclear industry employees; analysis from the nuclear industry family study.
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There has been much debate about paternal pre-conceptual exposure to low level ionising radiation and possible increased risk of ill health among the children subsequently conceived. The prevalence of reported learning difficulties was examined in over 16000 children born to UK nuclear industry workers, using fathers' information on exposure from the workers' individual employment and dosimetry records. There was no evidence that paternal exposure to low level ionising radiation at work influences the prevalence of learning difficulties in otherwise healthy children conceived after exposure. (+info)