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PubMed1984

In utero exposure to A-bomb radiation and mental retardation; a reassessment.

The prevalence of mental retardation in children exposed in utero to the atomic bombs in Hiroshima and Nagasaki has been re-evaluated in reference to gestational age and tissue dose in the fetus. There was no risk at 0-8 weeks post-conception. The highest risk of forebrain damage occurred at 8-15 weeks of gestational age, the time when the most rapid proliferation of neuronal elements and when most, if not all, neuroblast migration to the cerebral cortex from the proliferative zones is occurring. Overall, the risk is five or more times greater in these weeks than in subsequent ones. In the critical period, damage expressed as the frequency of subsequent mental retardation appears to be linearly related to the dose received by the fetus. A linear model is not equally applicable to radiation-related mental retardation after the 15th week, the observed values suggesting that there a threshold may exist. The data are consistent with a probability of occurrence of mental retardation of 0.40% per cGy or 40% per gray.

Brain↗
PubMed1991

Organ doses to atomic bomb survivors during photofluorography, fluoroscopy and computed tomography.

Doses to the salivary glands, thyroid gland, breast, lung, stomach and colon during mass radiological gastric screening, mass radiographic chest screening, upper gastrointestinal series and computed tomography were determined by exposing a female human phantom to simulated radiological X-ray examinations as performed in community hospitals. The doses were measured using thermoluminescent dosimeters, and the results will be used to document organ doses received by participants in the Atomic Bomb Casualty Commission/Radiation Effects Research Foundation Adult Health Study.

Adult↗
PubMed1991

[Effect on school performance of prenatal exposure to the Hiroshima atomic bomb].

As a part of the continuing assessment of the effects on the developing embryonic and fetal brain of exposure to ionizing radiation, the school performance of prenatally exposed survivors of the atomic bombing of Hiroshima and a suitable comparison group have been studied. In this report, the changes in performance in seven school subjects according to dose are compared under the dosimetry system (DS86) instituted in 1986 at the Radiation Effects Research Foundation. The sample involves 929 children whose fetal absorbed dose are known and includes 14 severely mentally retarded persons. The findings can be summarized as follows: 1) Damage to the 8-15 week fetal brain appears to be linearly related to the absorbed dose, as judged by the simple regression of average school-performance score on dose. Damage to the fetus exposed at 16-25 weeks after fertilization appears similar to that seen in the 8-15 week group. Canonical and multiple correlations also show a highly significant relationship of exposure 8-15 weeks and 16-25 weeks after fertilization to achievement in school. This trend is stronger, however, in the earliest years of schooling. 2) In the group exposed within 0-7 weeks following fertilization, or 26 or more weeks after fertilization, there was no evidence of a radiation-related effect on scholastic performance. 3) These results parallel those previously found in prenatally exposed survivors with respect to achievement in standard intelligence tests in childhood and development of severe mental retardation.

Age Factors↗
PubMed1989

Study of stomach cancer in atomic bomb survivors. Report 1. Histological findings and prognosis.

For the purpose of studying the histological findings and prognosis of stomach cancer in atomic bomb survivors, a histological diagnosis of 600 cases of stomach cancer observed between 1964 and 1986 in three medical institutions in Hiroshima City was made by a single pathologist and, furthermore, analysis of 231 cases thereof was performed using the DS86 dose estimated by the Radiation Effects Research Foundation. 1) By histological type of stomach cancer, the frequency of poorly differentiated adenocarcinoma (poorly differentiated adenocarcinoma and signet ring cell carcinoma) was significantly higher in the 1 rad or more group (average stomach organ dose of 30.6 rad) than in the 0 rad group. 2) As for stromal type, the frequency of scirrhous type was significantly higher in the 1 rad or more group, but no difference in infiltrative behavior could be demonstrated. 3) Early cancer tended to be observed at a low rate in the 1 rad or more group. 4) As for average survival time, of the early cancers only well differentiated adenocarcinoma showed a significantly lower survival time in the 1 rad or more group when compared to the 0 rad group.

Adenocarcinoma↗
PubMed1989

9;22 translocation and bcr rearrangements in chronic myelocytic leukemia patients among atomic bomb survivors.

To elucidate the mechanism of leukemia induced by radiation, we studied both chromosome abnormalities and bcr rearrangements of seven CML patients with a history of atomic bomb exposure and 14 CML patients without the exposure. All patients, irrespective of radiation exposure, had 9;22 translocation and rearrangement of the bcr gene in the leukemic cells. Further analysis of breakpoints within the bcr gene demonstrated no distinct difference between the exposed and the non-exposed groups. The present study suggests that formation of the chimeric bcr-abl gene and its genetic products may play an important role in the development of leukemia in either radiation-induced or de novo CML.

Adult↗
PubMed1989

The LD50 associated with exposure to the atomic bombing of Hiroshima.

Data on a total of 7,593 persons in Hiroshima who were in 2,518 wooden Japanese houses and exposed to A-bomb within 1.6 km from the hypocenter have been used to estimate the LD50/60. The effect of radiation shielding for these people in particularly well-characterized in the new dosimetry system DS86. A range of values emerge, varying slightly with the method of estimation used. This range, derived from DS86 marrow doses, and based on a linear fit to equally weighted estimates of the probabilities of death at various doses, is 2.3-2.6 Gy. A linear estimate in which the probabilities of death at the various doses are weighted by the inverse of their variances is somewhat lower, 2.2 Gy. These values may be underestimates of actual LD50/60 because of inclusion of deaths in the first day, and the severely injured (burns, trauma) who survived the first day but succumbed later to their injuries.

Data Collection↗
PubMed1991

Mortality among the offspring (F1) of atomic bomb survivors, 1946-85.

We compare the mortality in the years 1946-85 in a cohort of 31,159 children born to parents one or both of whom were exposed to the atomic bombing of Hiroshima and Nagasaki (a parental gonadal dose greater than or equal to 0.01 Sv) with that in a control group of 41,069 children. The average gonadal dose for the exposed parents was 0.435 Sv. The mean age of the cohorts was 28.8 years. In the greater than or equal to 0.01 Sv dose group 1,253 deaths were observed in the subset of children both of whose parents have been assigned DS86 doses. 3.2% were attributed to cancers, 72.9% to all diseases except neoplasms. These proportions in the 0 Sv dose group were about the same. Based on a linear relative risk model, no statistically significant increase in the mortality attributable to diseases other than neoplasms is noted following parental exposure, the excess relative risk being 0.030 (+/- 0.046) per sievert based on the DS86 doses (RBE of neutrons = 20). For fatal cancer, no statistically significant effect of parental radiation dose was also observed. An analysis based on the full sample, using not only the DS86 dose group but also ad hoc dose group, yields essentially the same results as the analysis restricted to the DS86 dose group.

Adult↗
PubMed1991

Mutation of RAS oncogene in atomic bomb radiation-exposed leukemia.

To determine what the role of RAS oncogene is in radiation-induced leukemia, we investigated the frequency of mutations and the sites of the base substitution of activated N- and K-RAS oncogenes in 25 leukemic patients who had been exposed to the atomic bomb and compared the results with those for 47 non-exposed leukemic patients. To detect the presence of mutated RAS oncogene, we used the PCR method to analyze DNAs from leukemic cells and from nude mouse tumors formed by in vivo selection assay. Eight of the 25 exposed leukemic patients (32%) and 13 of the 47 non-exposed leukemic patients (27.6%) had RAS oncogene mutations. No significant differences were found between the exposed and non-exposed groups in frequency of mutation and the sites of base substitution on the RAS oncogene sequence. This study should prove valuable for understanding the role of RAS oncogene mutation in the genesis of radiation-induced leukemias.

Base Sequence↗
PubMed1991

A review of forty-five years study of Hiroshima and Nagasaki atomic bomb survivors. Theoretical background of the Dosimetry System 86 (D586).

DS86 is a calculation code system for the estimation of the radiation dose of atomic bomb survivors at Hiroshima and Nagasaki. The DS86 calculation process is as follows: 1. Compute free-field radiation environment: radiation transport calculation can be done for the free air field at Hiroshima and Nagasaki. 2. Compute shielded radiation environment: depending on each shielding situation, the shielding can be calculated by using either the Nine-Shielding Parameter or the Globe Shielding Data. 3. Compute radiation environment at the organ site: organ kerma and fluence spectra can be calculated using a transport calculation code depending on each survivor sex, age, orientation and posture.

Humans↗
PubMed1991

Thyroid cancer: epidemiological study of thyroid cancer in A-bomb survivors from extended life span study cohort in Hiroshima.

We analysed thyroid cancers which were diagnosed clinically or detected at autopsy during 22 years (1958 to 1979) in a sample of 75,493 study subjects exposed in Hiroshima belonging to the extended LSS sample of the Radiation Effects Research Foundation. One hundred and twenty-five cases of clinical thyroid cancer (15 in males and 110 in females) were confirmed, giving a crude incidence rate per 100,000 person-years of 2.7 for males, 12.4 for females and 8.6 for both sexes combined. There was a significant increase of thyroid cancer with increase of atomic bomb radiation dose (thyroid tissue dose based on T65D) in females and in the sexes combined. This tendency was predominant in those exposed at less than 19 years of age. Compared to the control group, the relative risk in the greater than or equal to 0.50 Gy group was higher at 4.0 for males (not significant) and at 4.3 for females (p less than 0.01). Latent thyroid cancer was detected in 155 cases or 3.5% (2.5% for males and 4.5% for females) of the 4,425 cases that came to autopsy during the same period. Compared to the control group, the relative risk in the 50+ rad group was 1.7 for males (not significant), 2.0 for females (p less than 0.05) and 1.9 for both sexes combined (p less than 0.05). New data obtained from autopsy cases between 1950 and 1985 have been added.

Female↗
PubMed1991

Somatic cell mutations in atomic bomb survivors.

Mutant frequencies in peripheral blood lymphocytes and erythrocytes have been measured for atomic bomb survivors having various DS86 doses. Among the four assay systems utilized so far, erythrocyte glycophorin A assay revealed a dose related increase of mutant frequency, similar to the results obtained with in vitro mutagenesis studies at HPRT locus using human diploid cells. Mutant T-lymphocyte frequency of the HPRT locus detected as resistant to 6-thioguanine significantly increased with DS86 dose however the slope was very shallow compared with that of in vitro study. Mutation at T-cell receptor genes and the HLA-A gene did not show a significant increase in frequency with dose in cells of survivors studied.

Humans↗
PubMed1991

Studies of radioactivity produced by the Hiroshima atomic bomb: 2. Measurements of fallout radioactivity.

Three studies of fallout measurements were reviewed for the discussion of possible radioactivity intake from the Hiroshima atomic bomb. The first study discussed correlations between enriched 234U and 137Cs specific activities from the measurement of soil samples collected in the "black rain" area. The second study measured 137Cs activity on the rock and roof tile samples collected in the hypocenter area immediately after the explosion. Some of the rock and roof tile samples collected near the hypocenter had a small but detectable amount of 137Cs activity. However, it has been determined that 137Cs exposure, for example, was negligible compared with DS86 dose estimates, since these activity levels were low. The third study detected 90Sr activity in some of the specimens of human bones exhumed on Ninoshima Island. This study compared the difference in activity between the bone head and shaft, with higher activities obtained in the bone head. This fact suggests a short intake period for this activity, however, the levels of 90Sr contamination were too low to allow a discussion of the exposure risks.

Humans↗
PubMed1991

A review of forty-five years study of Hiroshima and Nagasaki atomic bomb survivors. Current summary of lymphocyte survival study.

A recently developed dose-survival assay in vitro using human G0 T-lymphocytes from peripheral blood was employed to assess possible interindividual variation of cellular radiosensitivity. Currently lymphocytes from a total of 99 atomic bomb survivors were tested and D10, the X-ray dose required to kill 90% of the cells, was calculated for each test. The mean +/- SD of D10 value was 3.35 +/- 0.22 Gy for 61 survivors whose DS86 dose is below 0.004 Gy and for 38 survivors of DS86 dose above 1.5 Gy it was 3.31 +/- 0.26 Gy. So far, the results do not show any evidence in support of the hypothesis of a selective elimination of a radiosensitive subcohort among the survivors exposed to high doses.

Cell Survival↗
PubMed1992

Colorectal cancer incidence among atomic bomb survivors, 1950-80.

Colorectal cancer incidence in the LSS sample during 1950-80 was investigated. A total of 730 incidence cases of colorectal cancer were confirmed from a variety of sources. Sixty-two percent of the cancers were microscopically verified and 12% were ascertained through death certificate only. The risk of colon cancer increased significantly with intestinal dose, but no definite increase of risk was observed for rectal cancer. Relative risk at 1 Sv and excess risk per 10(4) PY-Sv for colon cancer are 1.80 (90% confidence internal 1.37-2.36) and 0.36 (90% confidence interval 0.06-0.77) respectively. City and sex did not significantly modify the dose-response of colon cancer, but the risk decreased with age at the time of bombings (ATB). The relative risk of colon cancer does not vary substantially over time following exposure. A non-linear dose response did not significantly improve the fit. Further, the anatomic location of the tumors indicate that the cecum and ascending, transverse and descending, and sigmoid colon seem equally sensitive to radiation. No difference in the distribution of tumor histological types could be observed by radiation dose.

Adenocarcinoma↗
PubMed1999

Chromosomal instability in acute myelocytic leukemia and myelodysplastic syndrome patients among atomic bomb survivors.

To clarify the mechanism of leukemogenesis in atomic bomb survivors, leukemic cells were investigated using fluorescence in situ hybridization (FISH) analysis on the basis of conventional G-banding in patients with a history of radiation exposure and also in de novo patients. Conventional G-banding showed higher incidences (p < 0.005) of structural and numerical abnormalities without any specific types of chromosome aberrations in the group exposed to a dose of more than one Gy, compared to the non-exposed group. FISH analysis revealed significantly higher incidences (P < 0.05) of subclones with monosomy 7 and deletion of the 20q13.2 region, which were not found in conventional cytogenetic analysis in the exposed group (more than one Gy) compared to the non-exposed controls. Furthermore, segmental jumping translocation (SJT) of the c-MYC gene region was observed only in the exposed group. These chromosomal instability suggested that the leukemic cells from the heavily exposed patients contained persistent cellular genetic instability which may strongly influence the development of leukemia in people exposed to radiation.

Adult↗
PubMed1999

A crack model of the Hiroshima atomic bomb: explanation of the contradiction of "Dosimetry system 1986".

There has been a large discrepancy between the Dosimetry system 1986 (DS86) and measured data, some of which data in Hiroshima at about 1.5 km ground distance from the hypocenter are about 10 times larger than the calculation. Therefore its causes have long been discussed, since it will change the estimated radiation risks obtained based on the Hiroshima and Nagasaki data. In this study the contradiction was explained by a bare-fission-neutron leakage model through a crack formed at the time of neutron emission. According to the present calculation, the crack has a 3 cm parallel spacing, which is symmetric with respect to the polar axis from the hypocenter to the epicenter of the atomic bomb. We made also an asymmetric opening closing 3/4 of this symmetric geometry, because there are some data which shows asymmetry. In addition, the height of the neutron emission point was elevated 90 m. By using the asymmetric calculation, especially for long distant data located more than 1 km, it was verified that all of the activity data induced by thermal and fast neutrons, were simultaneously explained within the data scattering. The neutron kerma at a typical 1.5 km ground distance increases 3 and 8 times more than DS86 based on the symmetric and asymmetric model, respectively.

Humans↗
PubMed2002

The quality of DNA recovered from the archival tissues of atomic bomb survivors is good enough for the single nucleotide polymorphism analysis in spite of the decade-long preservation in formalin.

It is well known that the yield of DNA recovered form tissues preserved in formalin is inversely proportional to the stored duration. How is the quality? We tested the quality of DNA from archival tissues of atomic-bomb survivors stored in formalin for decades with the parameters of gene amplification efficiency by a polymerase chain reaction. All of the DNA extracted from the tissues preserved in formalin for 30 years amplified the 54- and 61-base pairs of the DNA fragments successfully. The direct sequencing of the PCR products confirmed the accurate amplification of the target sequence. A further trial to amplify the longer sequence of 111 base pairs succeeded in 20% of the samples tested. From these results, we propose a new utility of archival samples for the analysis of single nucleotide sequence polymorphism of genes, no matter how long the samples have been preserved in formalin.

Animals↗
PubMed2003

Measurement of residual 152Eu activity induced by atomic bomb neutrons in Nagasaki and the contribution of environmental neutrons to this activity.

Residual 152Eu activities induced by neutrons from the Nagasaki atomic bomb were measured for nine mineral samples located up to 1,061 m in the slant range and one control sample at 2,850 m from the hypocenter. A chemical separation to prepare europium-enriched samples was performed for all samples, and gamma ray measurements were carried out with a low background well-type germanium detector. In this paper, the measured specific activities of 152Eu are compared with activation calculations based on the DS86 neutron fluence and the 93Rev one. The calculated-to-measured ratios are also compared with those of 60Co and 36Cl. The present results indicate that the measurements agree to the calculation within a factor of three as observed in the nuclear tests at Nevada. The activation level of environmental neutrons and the detection limit for 152Eu are also discussed.

Background Radiation↗