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Further observations on abnormal brain development caused by prenatal A-bomb exposure to ionizing radiation.

The pervasiveness of abnormal brain development caused by prenatal exposure to ionizing radiation is still largely unknown. The relationship between A-bomb radiation dose and two measures of neuromuscular performance, one of grip strength and the other of the fine motor coordination required in repetitive action, is described. A multivariate analysis of covariance was used to evaluate the effect of several covariates, such as prenatal radiation exposure and some physical measurements or IQ adding city and sex as categorical factors. When mentally retarded cases were included, a statistically significant effect of radiation exposure on the grip strength and repetitive-action test scores was seen in the 8-15-week postovulation period, and a statistically suggestive effect at 16-25 weeks postovulation. No effect of radiation exposure on the two test scores was noted for prenatal exposure in either of the aforementioned periods when mentally retarded cases were excluded, but a statistically significant diminution of IQ was noted for exposures > or = 16 weeks postovulation. We discuss, from the biological perspective, the projected standard scores for exposures > or = 16 weeks postovulation, and the possibility of lower IQ, small head and mild mental retardation related to radiation exposures < or = 15 weeks postovulation with mentally retarded cases excluded.

Adolescent↗

Evidence for curvilinearity in the cancer incidence dose-response in the Japanese atomic bomb survivors.

The recently released data on cancer incidence in the Japanese atomic bomb survivors are analysed using a variety of relative risk models which take account of errors in estimates of dose to assess the dose-response at low doses. For all solid cancers analysed together there is a significant positive dose-response (at the one-sided 2.5% significance level) if all survivors who received < 0.5 Sv are considered, but the significance vanishes if doses of < 0.2 Sv are considered. If a relative risk model with a threshold (the dose-response being assumed linear above the threshold) is fitted to the solid cancer data, a threshold of more than about 0.2 Sv is inconsistent with the data, whereas these data are consistent with there being no threshold. Linear-quadratic models and linear-quadratic models with an exponential cell-sterilization term provide no better fit than the linear model. For the three main radiation-inducible leukaemia subtypes analysed together (acute lymphatic leukaemia, acute myeloid leukaemia and chronic myeloid leukaemia) there is a significant positive dose-response (at the one-sided 2.5% significance level) if all survivors who received < 0.5 Sv are considered, but the significance vanishes if doses of < 0.2 Sv are considered. If a relative risk model with a threshold (the dose-response being assumed linear above the threshold) is fitted to the leukaemia data, a thresh-old of more than about 0.3 Sv is inconsistent with the data. In contrast with the solid cancer data, the best estimate for the threshold level in the leukaemia data is significantly different from zero, even when allowance is made for a possible quadratic term in the dose-response, albeit at borderline levels of statistical significance (p = 0.04). There is little evidence for curvature in the leukaemia dose-response from 0.2 Sv upwards. However, the possible underestimation of the errors in the estimates of the dose threshold as a result of confounding and uncertainties not taken into account in the analysis, together with the lack of biological plausibility of a threshold, makes the interpretation of this finding questionable.

Humans↗

Estimates of neutron relative biological effectiveness derived from the Japanese atomic bomb survivors.

PURPOSE: To investigate neutron relative biological effectiveness. MATERIALS AND METHODS: The latest Japanese atomic bomb survivor cancer incidence and mortality datasets with the current (DS86) dosimetry system are analysed using generalized relative risk models and generalized absolute risk models, both with and without recently indicated adjustments to the Hiroshima DS86 neutron dose estimates. RESULTS: Without adjustments to the Hiroshima neutron doses, the best estimate of neutron relative biological effectiveness for all tumours in the incidence data is 63.3 (95% CI < 0-275.3) when a generalized relative risk model is used; when a generalized absolute risk model is used in the incidence data the best estimate is 53.5 (95% CI < 0-201.0); when a generalized relative risk model is used in the mortality data, the best estimate is 287.7 (95% CI 38.0- > 10[3]). When likely adjustments are made to the Hiroshima neutron doses the best estimate of neutron relative biological effectiveness in the incidence data using a generalized relative risk model is 15.1 (95% CI < 0-51.4); when a generalized absolute risk model is used in the incidence data the best estimate is 9.0 (95% CI < 0-32.9); when a generalized relative risk model is used in the mortality data the best estimate is 55.1 (95% CI 9.5-280.3). Although there are no significant differences between groupings of the solid tumour sites in their estimated neutron relative biological effectiveness, there are indications that the neutron relative biological effectiveness of solid tumours is lower than that of leukaemia, whether or not adjustments are made to the Hiroshima neutron dose estimates. Uncertainties in the likely adjustments to the DS86 Hiroshima neutron and gamma dose estimates as well as uncertainties in the modelling of excess risk in the two cities (Hiroshima and Nagasaki) imply that these findings should be treated with caution. CONCLUSIONS: Likely adjustments to the Hiroshima neutron dose estimates imply a substantial increase in information on neutron relative biological effectiveness. Whether or not adjustments are made to the Hiroshima neutron doses, there are indications of inconsistency between the estimates of neutron relative biological effectiveness for solid tumours and leukaemia. Dosimetric and modelling uncertainties mean that these findings should be treated with caution.

Humans↗

Radiation-related brain damage and growth retardation among the prenatally exposed atomic bomb survivors.

Many studies of prenatally exposed survivors of the atomic bombings of Hiroshima and Nagasaki have shown that exposure to ionizing radiation during gestation has harmful effects on the developing human brain. Data on the occurrence of severe mental retardation as well as variation in intelligence quotient (IQ) and school performance show significant effects on those survivors exposed 8-15 and 16-25 weeks after ovulation. Studies of seizures, especially those without a known precipitating cause, also exhibit a radiation effect in survivors exposed 8-15 weeks after ovulation. The biologic events that subtend these abnormalities are still unclear. However, magnetic resonance imaging of the brains of some mentally retarded survivors has revealed a large region of abnormally situated gray matter, suggesting an abnormality in neuronal migration. Radiation can induce small head size as well as mental retardation, and a review of the relationship between small head size and anthropometric measurements, such as height, weight, sitting height and chest circumference, shows that individuals with small head size have smaller anthropometric measurements than normocephalics. This suggests that radiation-related small head size is related to a generalized growth retardation. Finally, the issue of a threshold in the occurrence of one or more of these effects, both heuristically and from a regulatory perspective, remains uncertain. Simple inspection of the data often suggests that a threshold may exist, but little statistical support for this impression can be advanced, except in the instance of mental retardation.

Abnormalities, Radiation-Induced↗

A close correlation between electron spin resonance (ESR) dosimetry from tooth enamel and cytogenetic dosimetry from lymphocytes of Hiroshima atomic-bomb survivors.

PURPOSE: To estimate gamma-ray doses received by Hiroshima atomic bomb survivors using electron spin resonance (ESR) of tooth enamel and to compare the results with cytogenetic data. MATERIALS AND METHODS: Tooth enamel ESR was performed for 100 teeth donated from 69 Hiroshima survivors, and conventional cytogenetic examinations were conducted for 61 of the tooth donors. To evaluate possible contamination from dental X-ray exposure, which primarily affects the tooth's buccal surface, each tooth was divided into buccal and lingual parts for subsequent independent enamel isolation and ESR measurement. RESULTS: Almost 20 teeth showed considerably larger buccal doses than lingual doses, but most of these discrepant teeth were incisors and canines. The results are probably attributable to solar light exposure. In contrast, the buccal and lingual doses found in molars were similar. Conventional translocation data of lymphocytes and ESR-estimated doses of 40 donors of molars showed the dose-response for translocations to be almost the same as that expected from in vitro gamma-ray irradiation experiments. CONCLUSIONS: Both tooth enamel ESR and lymphocyte cytogenetics are useful measures for individual biodosimetry of acute radiation exposure, even half a century after the exposure occurred.

Aged↗

The course of posttraumatic stress disorder in a follow-up study of survivors of the Oklahoma City bombing.

BACKGROUND: The course of posttraumatic stress disorder (PTSD) in populations directly exposed to terrorist attacks is of major importance in the post-9/11 era. Because no systematic diagnostic studies of the most highly exposed individuals of the 9/11 terrorist attacks have yet been done, the Oklahoma City bombing remains a unique opportunity to examine PTSD over time in high-exposure terrorist victims. METHODS: This study assessed 137 survivors in the direct path of the explosion at approximately 6 and 17 months postdisaster, using the Diagnostic Interview Schedule. RESULTS: Combined index and follow-up data yielded a higher (41%) incidence of PTSD than detected at index (32%) or follow-up (31%). All PTSD was chronic (89% unremitted at 17 months) with no delayed-onset cases. The avoidance and numbing symptom group C, unlike groups B and D alone, was pivotal to current PTSD status and was associated with indicators of functioning at index and follow-up. The findings at index were sustainable. CONCLUSIONS: This follow-up study confirmed the immediacy of onset of PTSD and its persistence over time, pointing to the need for early interventions that continue over the long term. Group C avoidance and numbing symptoms may aid in early recognition of PTSD and in predicting long-term functioning.

Adult↗

A-bomb survivors: reassessment of the radiation hazard.

Newly released data from the Radiation Effects Research Foundation on the survivors of the Hiroshima and Nagasaki A-bombing allow a reassessment of radiation hazards. It appears that deaths from marrow damage (such as aplastic anaemia) continued after 1950. The Life Span Study cohort appears biased in favour of persons with high immunological competence, the result of infants and the elderly being more likely to die before 1950 than young adults. A study of survivors of in utero exposures suggests that embryos are more sensitive to the lethal effects of radiation than more mature foetuses. Current estimates of cancer risks from radiation may only apply to young adults with high immunological competence; young children and the elderly may be at greater risk.

Adult↗

Mobility of heavy metals originating from bombing of industrial sites.

Surface soil samples from the "NIS Jugopetrol" fuel storage sites has been studied. The aim of this work has been the detection of heavy and inorganic metals including As, Pb, Cd, Ni, Zn, Cr, and Cu in soils after bombing present due to outflow, burning or leaking of crude oil and oil products at five chosen locations: Belgrade-Cukarica, Smederevo, Nis, Bor and Prahovo. In order to get information of the future environmental and health risks, sampling was repeated after several months at the same locations. Certain locations present a threat on environment because of the possible transport of contaminants during higher water levels.

Explosions↗

High rate of candidemia in patients sustaining injuries in a bomb blast at a marketplace: a possible environmental source.

In this study, a cluster of candidemia among patients sustaining injuries in a bomb blast at a marketplace was investigated by means of a multivariate analysis, a case-control study, and quantitative air sampling. Candidemia occurred in 7 (30%) of 21 patients (58% of those admitted to the intensive care unit [ICU]) between 4 and 16 days (mean, 12 days) after the injury and was the single most frequent cause of bloodstream infections. Inhalation injury was the strongest predictor for candidemia by multivariate analysis. Candidemia among the case patients occurred at a significantly higher rate than among comparable trauma patients injured in different urban settings, including a pedestrian mall (2 of 29; P=. 02), and among contemporary ICU control patients (1 of 40; P=.001). Air sampling revealed exclusive detection of Candida species and increased mold concentration in the market in comparison with the mall environment. These findings suggest a role for an exogenous, environmental source in the development of candidemia in some trauma patients.

Adolescent↗

Exploring the city of Rubble: botanical fieldwork in bombed cities in Germany after World War II.

In recent decades, the flora and fuana of cities have become the objects of the inter-disciplinary research field of urban ecology and related policies of urban nature conservation. Although the term "urban ecology" is quite recent, it is argued in this paper that the formation of urban nature as an object of ecological knowledge has a much longer history. For example, in Germany, after World War II, the large rubble areas that existed in all bombed cities soon became important research fields for botanists studying plant migration and vegetation development in the context of the city. This paper uses the case of these botanical research activities to shed light on the historical origins of ecological thinking about nature in the city. Drawing upon a socio-spatial approach to science and practice, the paper explores the interaction between the social and material order of the city and the formation of ecological knowledge. As will be shown, botanists studying the rubble areas created various representations (e.g., lists, statistical tabulations, maps) of urban space that contributed to the transformation of the cultural and political meaning of urban wastelands. At the same time, it will be argued, urban wastelands were practically appropriated as scientific workplaces in which these representations were locally crafted. What later became the science and politics of urban ecology is to a large extent the outcome of this mutual shaping of knowledge and urban space in the post-Second World War period.

Botany↗

A comparison of the risk of stillbirth associated with paternal pre-conception irradiation in the Sellafield workforce with that of stillbirth and untoward pregnancy outcome among Japanese atomic bomb survivors.

A comparison is made of the relative risks associated with paternal preconception irradiation of stillbirth and untoward pregnancy outcome (stillbirths, congenital malformations, neonatal deaths) in the offspring of the Japanese atomic bomb survivors and of stillbirth in the offspring of Sellafield workers. It is concluded that the pre-conception exposure risks of stillbirth in the offspring of Sellafield workers are statistically incompatible with the Japanese data at the 5% level. Other human and experimental data relating to the induction of congenital abnormalities are briefly reviewed.

Abnormalities, Radiation-Induced↗

The implications of re-analysing radiation-induced leukaemia in atomic bomb survivors: risks for acute and chronic exposures are different.

Implications of risk estimates, as required for practical radiation protection purposes, were explored through a preliminary re-analysis of leukaemia in the Japanese atomic bomb survivors using a biologically based cancer model. The calculations for the risks posed for contracting leukaemia pointed to important differences between low-dose-rate ('chronic') and high-dose-rate ('acute') exposures. For example, the risks caused by long-term ('chronic') exposures are calculated to be substantially lower than those for 'acute' exposures. In view of these model predictions the results of epidemiological studies are discussed.

Aged↗

The status of the seventh report in the series Biological Effects of Ionizing Radiations and a revised dosimetry for the Radiation Effects Research Foundation's A-bomb studies.

Results of a National Academies workshop and feasibility study led US Governmental agencies to request the Board on Radiation Effects Research of the National Research Council to commence a risk assessment study in 1998 as the seventh report in the series Biological Effects of Ionizing Radiations (BEIR VII). Originally targeted for completion in the autumn of 2001, the study Potential Health Effects of Exposure to Low Dose, Low-LET Ionizing Radiation was extended until the autumn of 2003 at the request of the sponsors. Two factors contributing to this decision are discussed: a revised dosimetry to update DS86 for the Radiation Effects Research Foundation's A-bomb-survivor studies and the potential for new information to become available from low-dose studies that are under way. Epidemiological and biological data since BEIR V are being considered by a BEIR VII committee composed of 17 members. The committee's statement of task is reviewed along with the major recommendations of the recent National Research Council report on the status of DS86--recommendations that are being implemented by US and Japan dosimetry working groups.

Humans↗

The children of atomic bomb survivors: a synopsis.

When the atomic bombing of Hiroshima and Nagasaki occurred in the summer of 1945, most members of the public presumed that many of the children conceived by the survivors would be grossly deformed or seriously damaged in other ways as a consequence of radiation-induced mutations. Although the experimental data then available, largely limited to studies of Drosophila melanogaster, the common fruit fly, did not support this perception, the limitations of the data and the depth of public concern warranted a careful follow-up of the children born to the survivors. To this end a surveillance was begun in 1947 of all pregnancy outcomes after 20 weeks of gestation in these two cities. Over the half century subsequent to the initiation of this surveillance, some 80-odd thousand pregnancy outcomes have been studied and a variety of potential indicators of mutational damage measured. This report summarises the findings of these studies and offers an estimate of the genetic risk based on these findings.

Abnormalities, Radiation-Induced↗

Molecular interactions between Anopheles stephensi midgut cells and Plasmodium berghei: the time bomb theory of ookinete invasion of mosquitoes.

We present a detailed analysis of the interactions between Anopheles stephensi midgut epithelial cells and Plasmodium berghei ookinetes during invasion of the mosquito by the parasite. In this mosquito, P. berghei ookinetes invade polarized columnar epithelial cells with microvilli, which do not express high levels of vesicular ATPase. The invaded cells are damaged, protrude towards the midgut lumen and suffer other characteristic changes, including induction of nitric oxide synthase (NOS) expression, a substantial loss of microvilli and genomic DNA fragmentation. Our results indicate that the parasite inflicts extensive damage leading to subsequent death of the invaded cell. Ookinetes were found to be remarkably plastic, to secrete a subtilisin-like serine protease and the GPI-anchored surface protein Pbs21 into the cytoplasm of invaded cells, and to be capable of extensive lateral movement between cells. The epithelial damage inflicted is repaired efficiently by an actin purse-string-mediated restitution mechanism, which allows the epithelium to 'bud off' the damaged cells without losing its integrity. A new model, the time bomb theory of ookinete invasion, is proposed and its implications are discussed.

Actins↗

The rapid decomposition of biological materials by using a microwave acid digestion bomb.

A microwave acid decomposition technique was evaluated for decomposing biological standard reference materials (NBS oyster tissue and bovine liver) for trace metal analyses. Dissolution consisted of HNO3 decomposition in a closed Teflon bomb. A microwave oven was used as the heat source. Complete decomposition times were less than 1 min. Resulting solutions were analyzed by atomic absorption spectrophotometry for Cd, Cu, Fe, Pb, and Zn. Recoveries were estimated by comparison with National Bureau of Standards certified values. The precision and accuracy of the results ranged from 1 to 13% and 93 to 106%, respectively.

Animals↗

Male breast cancer incidence among atomic bomb survivors.

To learn more about the role of ionizing radiation in the development of male breast cancer, we evaluated male breast cancer incidence among 45 880 male members of the Life Span Study cohort of Japanese atomic bomb survivors. Male breast cancers, diagnosed between January 1, 1958, and December 31, 1998, were identified through the Hiroshima and Nagasaki Tumor Registries. Nine male breast cancers were diagnosed among exposed Life Span Study members (crude rate = 1.8 per 100,000 person-years), and three were diagnosed among nonexposed cohort members (crude rate = 0.5 per 100,000 person-years). A statistically significant dose-response relation was observed (excess relative risk per sievert = 8, 95% confidence interval = 0.8 to 48; P = .01). Our finding of a statistically significant association between ionizing radiation and male breast cancer incidence adds to the very limited information that shows an association between radiation exposure and an increased risk of male breast cancer.

Aged↗