Regression analysis of time trends in perinatal mortality in Germany 1980-1993.
(17/256)
Numerous investigations have been carried out on the possible impact of the Chernobyl accident on the prevalence of anomalies at birth and on perinatal mortality. In many cases the studies were aimed at the detection of differences of pregnancy outcome measurements between regions or time periods. Most authors conclude that there is no evidence of a detrimental physical effect on congenital anomalies or other outcomes of pregnancy following the accident. In this paper, we report on statistical analyses of time trends of perinatal mortality in Germany. Our main intention is to investigate whether perinatal mortality, as reflected in official records, was increased in 1987 as a possible effect of the Chernobyl accident. We show that, in Germany as a whole, there was a significantly elevated perinatal mortality proportion in 1987 as compared to the trend function. The increase is 4.8% (p = 0.0046) of the expected perinatal death proportion for 1987. Even more pronounced levels of 8.2% (p = 0. 0458) and 8.5% (p = 0.0702) may be found in the higher contaminated areas of the former German Democratic Republic (GDR), including West Berlin, and of Bavaria, respectively. To investigate the impact of statistical models on results, we applied three standard regression techniques. The observed significant increase in 1987 is independent of the statistical model used. Stillbirth proportions show essentially the same behavior as perinatal death proportions, but the results for all of Germany are nonsignificant due to the smaller numbers involved. Analysis of the association of stillbirth proportions with the (137)Cs deposition on a district level in Bavaria discloses a significant relationship. Our results are in contrast to those of many analyses of the health consequences of the Chernobyl accident and contradict the present radiobiologic knowledge. As we are dealing with highly aggregated data, other causes or artifacts may explain the observed effects. Hence, the findings should be interpreted with caution, and further independent evidence should be sought. (+info)
Two cases of thyroid cancer in a small workforce.
(18/256)
In 1994, in a large parcel depot in the north of England employing 600 staff and 24 electrical and mechanical engineers, two engineers developed papillary cell carcinoma of the thyroid in the same year. A comprehensive review of the literature revealed that ionizing radiation is the only known direct cause of this disease. There was speculation that air filter changing undertaken by the two men affected, shortly after the Chernobyl accident in 1986, may have exposed them to concentrated radioactive fallout. A radiation survey of the parcel depot was undertaken and revealed no evidence of abnormal radioactivity. A total of 27 past and present engineering staff were screened for thyroid cancer. No cases of thyroid cancer were found. Investigation of clusters of rare disease in the occupational setting is indicated mainly in order to address the concerns of the workforce. Nevertheless, investigation is warranted, especially when the aetiology of a disease is poorly understood. It would be prudent for doctors, in whatever speciality, to take an occupational history from individuals who develop thyroid cancer. (+info)
Pattern of radiation-induced RET and NTRK1 rearrangements in 191 post-chernobyl papillary thyroid carcinomas: biological, phenotypic, and clinical implications.
(19/256)
Molecular genetic aberrations and the related phenotypes were investigated in 191 papillary thyroid carcinomas (PTCs) from patients exposed at young age to radioiodine released from the Chernobyl reactor. A high prevalence of RET gene rearrangements (62.3%) with a significant predominance of ELE1/RET (PTC3) over H4/RET (PTC1) rearrangements was found in PTCs of the first post-Chernobyl decade. NTRK1 rearrangements were rare (3.3%). In 3.3%, we observed novel types of RET rearrangements: GOLGA5/ RET (PTC5), HTIF/RET (PTC6), RFG7/RET (PTC7), and an as yet undefined RFGX/RET.RET rearrangements, preferentially ELE1/RET, are related to rapid tumor development. At longer intervals after exposure to ionizing radiation, the prevalence of RET rearrangements declines with a shift from ELE1/RET to H4/RET, most significantly in female patients. The prevalence of specific types of rearrangements is independent of age at irradiation. A significantly higher prevalence of ELE1/RET was observed in the most heavily contaminated Oblasts, Gomel and Brest, suggesting a preferential formation of this type of rearrangement after high thyroid doses. RET rearrangement is related to aggressive growth: Rearrangement-positive PTCs were in a more advanced pT category and more frequently in the pN1 category at presentation than rearrangement-negative PTCs. ELE1/RET is related to the solid variant of PTC, H4/RET more frequently to typical papillary structures. The genotype/phenotype evaluation of post-Chernobyl PTCs reveals a characteristic spectrum of gene rearrangements that lead to typical phenotypes with important biological and clinical implications. (+info)
Improvement of accuracy of chromosome aberration analysis for biological radiation dosimetry.
(20/256)
The frequency of chromosome aberrations in circulating lymphocytes is accepted as being the most reliable indicator of the absorbed dose of radiation. Researches done to improve the accuracy of cytogenetic analysis are described in this review. These include investigations of in vitro factors that affect the yield of radiation-induced aberrations and of in vivo factors that affect the chromosomal radiosensitivity of individuals. Improved chromosome-painting methods for accurate judgment of dicentrics and translocations are introduced. The practicality of these advanced cytogenetic techniques is shown by examinations of individuals exposed in the radiation accident at Tokaimura in 1999. (+info)
Translocation t(10;14)(q11.2:q22.1) fusing the kinetin to the RET gene creates a novel rearranged form (PTC8) of the RET proto-oncogene in radiation-induced childhood papillary thyroid carcinoma.
(21/256)
Evaluation of 20 cases of radiation-induced childhood papillary thyroid carcinoma using fluorescence in situ hybridization demonstrated the presence of clonal translocations affecting the RET locus. Semiquantitative reverse transcription-PCR indicated overexpression of the RET tyrosine kinase (TK) domain in four cases. In two cases, the RET rearrangements PTC6 and PTC7 were identified and assigned to balanced translocations t(7;10)(q32;q11.2) and t(1;10)(p13;q11.2), respectively. In one case with a balanced translocation t(10;14)(q11.2;q22.1), 5' rapid amplification of cDNA ends revealed a novel type of RET oncogenic activation (PTC8), arising from a fusion of the 5' part of the kinectin (KTN1) gene to the TK domain of the RET gene. The presence of coiled-coil domains in the resulting ktn1/ret fusion protein suggests ligand-independent dimerization and thus constitutive activation of the ret TK domain. (+info)
Mortality among the residents of the Three Mile Island accident area: 1979-1992.
(22/256)
The largest U.S. population exposed to low-level radioactivity released by an accident at a nuclear power plant is composed of residents near the Three Mile Island (TMI) Plant on 28 March 1979. This paper (a collaboration of The University of Pittsburgh and the Pennsylvania Department of Health) reports on the mortality experience of the 32,135 members in this cohort for 1979-1992. We analyzed standardized mortality ratios (SMRs) using a local comparison population and performed relative risk regression modeling to assess overall mortality and specific cancer risks by confounding factors and radiation-related exposure variables. Total mortality was significantly elevated for both men and women (SMRs = 109 and 118, respectively). All heart disease accounted for 43.3% of total deaths and demonstrated elevated SMRs for heart disease of 113 and 130 for men and women, respectively; however, when controlling for confounders and natural background radiation, these elevations in heart disease were no longer evident. Overall cancer mortality was similar in this cohort as compared to the local population (male SMR = 100; female SMR = 101). In the relative risk modeling, there was a significant effect for all lymphatic and hematopoietic tissue in males in relation to natural background exposure (p = 0.04). However, no trend was noted. We found a significant linear trend for female breast cancer risk in relation to increasing levels of TMI-related likely [gamma]-exposure (p = 0.02). Although such a relationship has been noted in other investigations, emissions from the TMI incident were significantly lower than in other documented studies. Therefore, it is unlikely that this observed increase is related to radiation exposure on the day of the accident. The mortality surveillance of this cohort does not provide consistent evidence that radioactivity released during the TMI accident has a significant impact on the mortality experience of this cohort to date. However, continued follow-up of these individuals will provide a more comprehensive description of the morbidity and mortality experience of the cohort. (+info)
Modelling of skin exposure from distributed sources.
(23/256)
A simple model of indoor air pollution concentrations was used together with experimental results on deposition velocities to skin to calculate the skin dose from an outdoor plume of contaminants. The primary pathway was considered to be direct deposition to the skin from a homogeneously distributed air source. The model has been used to show that skin deposition was a significant dose contributor for example when compared to inhalation dose. (+info)
Schizophrenia spectrum disorders in persons exposed to ionizing radiation as a result of the Chernobyl accident.
(24/256)
We studied schizophrenia spectrum disorders in Chernobyl accident survivors by analyzing Chernobyl exclusion zone (EZ) archives (1986-1997) and by conducting a psychophysiological examination of 100 patients with acute radiation sickness (ARS) and 100 workers of the Chernobyl EZ who had worked as "liquidators-volunteers" for 5 or more years since 1986-1987. Beginning in 1990, there has been a significant increase in the incidence of schizophrenia in EZ personnel in comparison to the general population (5.4 per 10,000 in the EZ versus 1.1 per 10,000 in the Ukraine in 1990). Those irradiated by moderate to high doses (more than 0.30 Sv or 30 rem), including ARS patients, had significantly more left frontotemporal limbic and schizophreniform syndromes. We hypothesized that ionizing radiation may be an environmental trigger that can actualize a predisposition to schizophrenia or indeed cause schizophrenia-like disorders. The development of schizophrenia spectrum disorders in overirradiated Chernobyl survivors may be due to radiation-induced left frontotemporal limbic dysfunction, which may be the neurophysiological basis of schizophrenia-like symptoms. Persons exposed to 0.30 Sv or more are at higher risk of schizophrenia spectrum disorders. An integration of international efforts to discuss and organize collaborative studies in this field is of great importance for both clinical medicine and neuroscience. (+info)