Selective accumulation of ALA-induced PpIX and photodynamic effect in chemically induced hepatocellular carcinoma

The possibility of 5-aminolaevulinic acid-based photodynamic therapy (ALA-PDT) for liver cancer was investigated using a chemically induced hepatocellular carcinoma (HCC) model. Endogenously synthesised protoporphyrin IX (PpIX) following the administration of ALA is an effective photosensitiser for PDT. We determined the fluorescence intensity of PpIX in HCC and nontumoral tissue in the liver. 5-Aminolaevulinic acid was intravenously injected to male Fisher rats with HCC at a dose of 500 mg x kg(-1), and the fluorescence intensity in each tissue sample excised from liver was measured with a spectrofluorometer at 1, 3 and 6 h after administration. Fluorescence intensity was at a peak of 3 h after administration in both HCC and nontumoral tissue. The accumulation of PpIX in HCC was higher than that in the nontumoral tissue at 1 h (P<0.001) and 3 h (P<0.05) after ALA administration. Based on these results, PDT was performed on HCC at 3 h after 500 mg x kg(-1) ALA administration before laser irradiation of 30 J per tumour. Antitumour effect was more evident in HCC than in the nontumoral tissue surrounding HCC. These findings suggest the possibility to detect HCC by fluorescence and to treat HCC by light.

An inferior mesenteric-caval shunt via the internal iliac vein with portosystemic encephalopathy

We report here a case of an unusual extrahepatic portosystemic venous shunt in a 37-year-old woman without liver cirrhosis or portal hypertension, who developed portal systemic encephalopathy. Angiography demonstrated an inferior mesenteric-caval shunt characterized by the presence of direct communication of the inferior mesenteric vein with the left internal iliac vein. After the treatment with percutaneous transcatheter embolization of the shunt via a femoral vein approach using coils, she had no episode of portal systemic encephalopathy.

[A study of institutional medical care of female victims of sexual assault and violence]

OBJECTIVE

The purpose of the study is to clarify the present situation of medical care for victims of sexual assault and violence. Medical facilities in two wards in Tokyo were studied in order to know what problems regarding medical care exist and how to support female victims.

METHODS

In April 1998, we distributed questionnaires to 338 medical facilities covering all the clinics and hospitals, that had more than only otorhinolaryngology and ophthalmology, in Kouto-ku and Sumida-ku, Tokyo. The questionnaire included questions about individual experience of consulting with sexual assault and violence against women, the number of victims in the last year, and their understandings for victims.

RESULT

1) 76 of the respondents completed the answer sheet by themselves. The mean age of the subjects was 57.4 years old, 16.3% of them had seen sexual assault victims, and about 36.8% had cared for victims of violence. 2) 67 victims of sexual assault and violence were reported in the previous year. 36% of victims of sexual assault were reported by facilities related to obstetrics, and 85% of victims of violence were reported by general medical facilities. 3) As for understandings for victims, those who thought the victims were responsible for the sexual assault also regarded violence as caused by carelessness of victims.

CONCLUSION

Medical facilities may be an important place to care for victims of sexual assault and violence against women. There are few data available as to how many women suffer from sexual violence. This study showed for the first time the reality of sexual assault and violence from the viewpoints of medical facilities in Japan, although it had some limitations. It is necessary for more discussion about roles of medical care for female victims of sexual assault and violence.

Changes in the pattern of growth in stature related to prenatal exposure to ionizing radiation

PURPOSE

To examine the pattern and spurt in growth and development of prenatally exposed atomic-bomb survivors and to determine whether a statistically significant radiation-related growth retardation exists.

MATERIALS AND METHODS

The stature of 1566 individuals exposed prenatally to the atomic bombings has been employed to study the effect of such exposure on growth. Among these survivors, 30 were severely mentally retarded, and 66 individuals on whom no physical measurements between ages 9 and 19 exist were excluded from this study. Thus this analysis rests on the measurements obtained on 1470 survivors 9 to 19 years of age at the time of examination.

RESULTS

When the > or =0.50 Sv group was compared to the other two prenatally exposed groups, a significant retardation of growth was observed only among those survivors exposed in the first trimester of gestation. The onset of the growth spurt among males in the three exposure groups was at approximately the same age, 11.34 years, but this was not true in females. The maximum velocity in growth for males was at 14.38 years of age, but for females no clear peak velocity was demonstrable.

CONCLUSION

A radiation-related growth retardation was demonstrable in this longitudinal study of the stature of individuals prenatally exposed. It is further demonstrated that among these survivors the growth velocity was faster in the high-dose group than in the low-dose group for both males and females.

Cognitive function and prenatal exposure to ionizing radiation

It is clear from the many studies of the prenatally exposed survivors of the atomic bombing of Hiroshima and Nagasaki that exposure to ionizing radiation during gestation has harmful effects on the developing human brain, particularly if that exposure occurs at critical stages in the development of the neocortex. Data on a variety of measures of cognitive function, including the occurrence of severe mental retardation as well as variation in the intelligence quotient (IQ) and school performance, show significant effects on those survivors exposed 8-15 weeks and 16-25 weeks after ovulation. Studies of seizures, primarily those without known precipitating cause, also exhibit a radiation effect on those individuals exposed in the first 16 weeks after ovulation. The cellular and molecular events that subtend these abnormalities are still largely unknown although some progress toward an understanding has occurred. For example, magnetic resonance imaging of the brain of some of the mentally retarded survivors has revealed a large region of abnormally situated gray matter, suggesting an abnormality in neuronal migration, but cell killing could also contribute importantly to the effects on cognitive function that have been seen. The retardation of growth in stature observed in individuals exposed in the first and second trimesters of pregnancy suggests that the development of an atypically small head size, without conspicuously impaired cognitive function, may reflect a generalized retardation of growth.

Cognitive function and prenatal exposure to ionizing radiation

It is clear from the many studies of the prenatally exposed survivors of the atomic bombing of Hiroshima and Nagasaki that exposure to ionizing radiation during gestation has harmful effects on the developing human brain, particularly if that exposure occurs at critical stages in the development of the neocortex. Data on a variety of measures of cognitive function, including the occurrence of severe mental retardation as well as variation in the intelligence quotient (IQ) and school performance, show significant effects on those survivors exposed 8-15 weeks and 16-25 weeks after ovulation. Studies of seizures, primarily those without known precipitating cause, also exhibit a radiation effect on those individuals exposed in the first 16 weeks after ovulation. The cellular and molecular events that subtend these abnormalities are still largely unknown although some progress toward an understanding has occurred. For example, magnetic resonance imaging of the brain of some of the mentally retarded survivors has revealed a large region of abnormally situated gray matter, suggesting an abnormality in neuronal migration, but cell killing could also contribute importantly to the effects on cognitive function that have been seen. The retardation of growth in stature observed in individuals exposed in the first and second trimesters of pregnancy suggests that the development of an atypically small head size, without conspicuously impaired cognitive function, may reflect a generalized retardation of growth.

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.

Preventive effects of polysaccharides extracted from human tubercle bacilli (specific substance of Maruyama) on colonic carcinogenesis in rats

Polysaccharides extracted from human tubercle bacilli (specific substance of Maruyama [SSM]) have been clinically applied with satisfactory results. Thymidylate synthetase (TS) and thymidine kinase (TK) are key enzymes in de novo and salvage pathways for pyrimidine nucleotide synthesis. Well- and moderately well differentiated adenocarcinomas induced with 1,2-dimethylhydrazine (DMH) are widely distributed throughout the colorectal tract with high TK activity, and the poorly differentiated type is mainly restricted in the proximal colon and the cecum with high TS activity in rats. Subcutaneously injecting the rats with SSM reduced TS activity in colonic nontumorous regions, but in the tumorous regions it reduced TK activity compared with that of the DMH-treated rats without SSM treatment. SSM is suggested to reduce the colorectal carcinogenesis induced with DMH by inhibiting DNA synthesis in a de novo pathway, and to suppress the development of the tumors by decreasing DNA synthesis in the salvage pathway in rats.

Threshold for radiation-related severe mental retardation in prenatally exposed A-bomb survivors: a re-analysis

Significant effects on the developing human brain of exposure to ionizing radiation are seen among individuals exposed in the 8th-25th week after ovulation. These effects, particularly in the highly vulnerable period of 8-15 weeks after ovulation, manifest themselves most dramatically as an increased frequency of severe mental retardation. However, the distribution of cases of severe mental retardation suggests a threshold in the low-dose region. The 95% lower bound of the threshold in those survivors exposed 8-15 weeks after ovulation was zero for the individual data based on the simple linear model, and 0.15 Gy based on the exponential linear model used in our previous report (1987), but the 95% lower bound of the threshold based on all of the data including 21 additional cases with known doses appears to be 0.05 Gy using the maximum likelihood estimates derived from an exponential-linear model. The latter model was selected because it provides the best fit from the standpoint of the stableness and reasonableness of the estimates among the five models applied to the data. When two probably non-radiation-related cases of Down's syndrome are excluded from the 19 mentally retarded cases exposed 8-15 weeks post ovulation, the 95% lower bound of the threshold is in the range of 0.15-0.25 Gy based on the exponential-linear model used in 1987, but is in the range of 0.06-0.31 Gy when the more reasonable and better model applied here is used. For exposure in the 16-25-week period based on the same model, the 95% lower bound of the threshold changed from 0.25 to 0.28 Gy, both with and without inclusion of the two probable non-radiation-related mentally retarded cases; one of these cases was probably familial in origin since there was a retarded sibling, and the other due to infection, since the individual had Japanese B encephalitis at age 4 years.

Cataract in atomic bomb survivors based on a threshold model and the occurrence of severe epilation

This report re-examines the relationship of radiation dose to the occurrence of cataracts among 1742 atomic bomb survivors seen in the years 1963-1964 for whom the degree of epilation and Dosimetry System 1986 (DS86) doses are known. Of these individuals, 67 had cataracts. A relative risk model with two thresholds, one for the epilation group and the other for the no-epilation group, has been fitted to the data using a binomial odds regression approach and a constant relative biological effectiveness (RBE) for neutrons of 10. Among these models, a linear-linear (L-L) dose-response relationship with two thresholds presents the best fit. Under the L-L threshold model based on DS86 eye organ dose estimates for the epilation and no-epilation groups, the slope estimate for the epilation group was 1.6-2.0 times greater than that for the no-epilation group, but no statistical difference between the two slope estimates was noted. The estimated threshold for the epilation group was 0.86 Sv and 1.54 Sv for the no-epilation group, but again the difference between the two threshold estimates is not statistically significant. When an L-L relative risk model with two thresholds was fitted to the data assuming the dose estimates to be in error by 35%, or when the data were restricted to the 1105 individuals exposed in Japanese houses at distances of less than 2500 m, where the DS86 doses are thought to be most reliable, the results were almost the same as those for the individuals for whom unadjusted DS86 eye organ dose estimates were used.

Acute disseminated encephalomyelitis associated with Mycoplasma pneumoniae infection

An 8 year old girl with acute disseminated encephalomyelitis (ADEM) is described. Elevated serum antibody titers suggested recent Mycoplasma pneumoniae infection. T2-weighted image of magnetic resonance imaging (MRI) disclosed multiple lesions of high signal intensity in bilateral basal ganglia and thalami as well as in the white matter. Postcontrast T1-weighted image revealed an enhanced lesion in the deep white matter. She showed rapid clinical improvement in response to corticosteroid therapy. The lesions had disappeared completely on MRI performed 10 weeks after the onset. ADEM is believed to be a demyelinating disorder of probable autoimmune etiology. MRI findings in this case may support the hypothesis that the primary pathological event is vascular injury and demyelination occurs only as a secondary phenomenon.

Relationship between cataracts and epilation in atomic bomb survivors

Among 1713 atomic bomb survivors who underwent ophthalmological examinations from 1963-1964, the risk of cataract formation per unit dose of radiation was significantly greater for those who reported hair loss of 67% or more after exposure (the epilation group) than for those who reported less or no hair loss (the no-epilation group) (P < 0.01). Such an epilation effect has also been associated with leukemia mortality and the frequency of chromosome aberrations. Although this might be interpreted as indicating differential sensitivity to radiation between the epilation group and the no-epilation group, it could also be explained by imprecision in dose estimates. We have calculated that a 48% random error in DS86 dose estimates could be in accordance with the dose-response relationship for the prevalence of cataracts in the epilation group or the no-epilation group. Possible mechanisms for variation in radiosensitivity are discussed.

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.

Evidence of radiation-induced reduction of height and body weight from repeated measurements of adults exposed in childhood to the atomic bombs

Reduction of growth from exposure to atomic bomb radiation has been examined using individuals under 10 years old at the time of the bombing (ATB) and a growth curve analysis based on measurements of height and weight made in the course of the 4th-7th cycles of the Adult Health Study examinations (1964-1972). As expected, the largest difference in growth to emerge is between males and females. However, a highly significant reduction of growth associated with dose (DS86) was observed among those survivors for whom four repeated measurements of height and weight were available. Longitudinal analysis of a more extended data set (n = 821), using expected values based on simple linear regression models fitted to the three available sets of measurements of height and weight on the 254 individuals with a missing measurement, also indicates a significant radiation-related growth reduction. The possible contribution of such factors as poor nutrition and disruption of normal family life in the years immediately after the war is difficult to evaluate, but the effects of socioeconomic factors on the analysis of these data are discussed.

Effects of environmental factors on perinatal outcome: neurological development in cases of intrauterine growth retardation and school performance of children perinatally exposed to ionizing radiation

We performed two studies to investigate environmental factors in relation to neurological development in infants. The first, a field study, examined the elementary school performance of 929 children who were born from mothers exposed to the atomic bombing of Hiroshima, Japan, August 6, 1945. The most severe mental retardation was observed in the group exposed between 8 and 15 weeks following fertilization, and the second most severely damaged group was exposed between 16 and 25 weeks. The second, a clinical investigation, examined infants in the perinatal center who survived intrauterine growth retardation (IUGR). Those who survived with abnormal neurological development had a mean growth arrest corresponding to a uterine height of 27 weeks of gestation. This was at an earlier stage than those who survived with normal neurological development and had a mean growth arrest corresponding to 29-30 weeks of gestation. A smaller head circumference at birth was closely correlated with abnormal neurological sequelae. These results indicate that the brain development of the fetuses may have been affected by neurotoxic events similar to ionizing radiation. We emphasize the importance of avoiding neurotoxic stress to pregnant women when the fetus is in the critical period of neuronal development, before 27 weeks of gestational age.

A longitudinal study of growth and development of stature among prenatally exposed atomic bomb survivors

Growth retardation due to exposure to the atomic bomb has been evaluated using repeated measurements of stature from 10 to 18 years of age. A highly significant growth retardation due to the DS86 uterine dose was observed in all trimesters combined and in the first and second trimesters of pregnancy. In the first trimester, all parameter estimates based on a linear (L) or linear-quadratic (L-Q) dose-response relationship were negative in relation to the DS86 uterine dose. The positive dose estimate in the second trimester is small and close to the control level. Statistically significant difference was determined by a multivariate test statistic examining whether or not a set of two- or three-parameter estimates including a constant term related to an L or L-Q dose-response relationship was different from zero. A radiation-related growth retardation was demonstrable as a longitudinal result of the repeated measurements of stature. The dose effect in the third trimester was not significant under either the L or the L-Q model. The relationship between birth weights and repeated measurements of stature in adolescence is discussed based on the results obtained by a growth curve analysis.

Radiation-related small head sizes among prenatally exposed A-bomb survivors

Of 1566 individuals prenatally exposed to the atomic bombings of Hiroshima and Nagasaki, 1473 had the circumference of their head measured at least once between ages 9 and 19. Among these 1473 individuals, 62 had small heads--the circumference of the heads was two standard deviations or more below the observed specific-age-at measurement mean. Of 26 cases with severe mental retardation, 15 (58%) had small heads. Most (86%) of the individuals with small heads were exposed in the first trimester (about < 12 weeks postovulation) or second trimester (about 12-24 weeks postovulation)--55% in the former period and 31% in the latter. Various dose-response relationships, with and without a threshold, have been fitted to the data grouped by the trimester or postovulatory age (weeks after ovulation) at which exposure occurred. A significant effect of radiation on the frequency of individuals with atypically small heads is observed only in the first and second trimesters and for the intervals postovulation of 0-7 weeks and 8-15 weeks. Although the risk of a small head at 0-7 weeks postovulation increases significantly with increasing dose, no increase in risk for severe mental retardation is noted in this period. No excess risk of a small head was seen in the third trimester (about > or = 25 weeks postovulation) or among individuals exposed at 16 weeks or more postovulation. The mean IQ values of mentally retarded cases with and without small heads were 63.8 and 68.9, respectively. No significant difference exists between these two IQ means, but both were significantly smaller than 96.4, the IQ value for individuals with small heads without severe mental retardation and 107.8, the value for the overall sample.

Radiation-related ophthalmological changes and aging among Hiroshima and Nagasaki A-bomb survivors: a reanalysis

The relationship of ionizing radiation to the age-related ophthalmological findings of the 1978-1980 ophthalmological examination of A-bomb survivors of Hiroshima and Nagasaki has been reanalyzed using DS86 eye organ dose estimates. The main purpose of this reevaluation was to determine whether age and radiation exposure, as measured using the recently revised dosimetry information (DS86), have an additive, synergistic, or antagonistic effect. The data in this study are limited to axial opacities and posterior subcapsular changes, for which a definite radiation-induced effect has been observed in Hiroshima and Nagasaki A-bomb survivors. The best model fitting for axial opacities gives a significant positive effect for both linear dose and linear age-related regression coefficients and a significant negative effect for an interaction between radiation dose and age. Such a negative interaction implies an antagonistic effect in that the relative risks in relation to radiation exposure doses become smaller with an increase in age. On the other hand, the best-fitting relationship for posterior subcapsular changes suggested a linear-quadratic dose and linear age-related effect. The estimate of the quadratic dose coefficient shows a highly negative correlation with age, but the negative quadratic dose term is extremely small and is of little biological significance.

Effect of Nocardia rubra cell-wall skeleton on cancer prevention in humans

The retired workers at the chemical weapons plant in Japan are regarded as a high-risk group for cancers. Under the Cancer Preventive Program, Nocardia rubra cell-wall skeleton (N-CWS) was administered to 80 workers directly involved in the production of sulfur mustard and 66 workers engaged in work related to sulfur mustard production. Untreated workers whose age, sex, duties and duration of work at this factory were individually matched to the N-CWS-treated workers were used as controls. During a 4.5-year observation period, development of cancers was found in 7 treated workers and 17 untreated controls. After elimination of the influence of the difference in smoking level, the incidence of subjects who developed cancers was compared statistically between the N-CWS-treated workers and the untreated controls and a significant suppression of development of cancers was noted in the N-CWS-treated workers. Thus, it was concluded that the administration of N-CWS could prevent cancer development in humans.

[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.

Topography of Alzheimer's neurofibrillary change distribution in myotonic dystrophy

Histological changes that explain the mental symptoms of patients with myotonic dystrophy (MD) have not fully been demonstrated yet. Recently, the presence of Alzheimer's neurofibrillary changes (ANCs) in the brain have been reported in this disease. We studied the brain of a 61-year-old male with MD. The distribution of ANCs was investigated and mapped through careful histological examinations. The examinations disclosed that in MD, ANCs distributed along their preferential sites of the brain; a great number of ANCs were found in the parahippocampus, hippocampus, amygdaloid nucleus, fusiform gyrus, insula, and olfactory bulb, many in the nucleus basalis of Meynert, inferior temporal gyrus, hypothalamus, and brain stem, and a few in the cingulate, frontal and temporal gyri, neostriatum, and mammillary body. In the brain stem, ANCs were seen in the central gray, oculomotor nucleus, linear nucleus, substantia nigra, locus coeruleus, dorsal raphe nucleus, superior central nucleus, retriculotegmental nucleus, and reticular formation. From this result and the previous reports by others, it may be suggested that the presence of ANCs concentrated mostly in the limbic system is a regular and significant histological finding in the brain in MD. Therefore, this limbic lesion must be related to some of the mental symptoms unique to MD. In addition, diffuse and considerable neuronal atrophy and gliosis in the thalami in the absence of ANCs also may have played a causative role in some of the mental symptoms of the present case. Besides the more concentrated occurrence of ANCs within the limbic system, the minimal presence of senile plaques in the CNS may differentiate the brain in MD from that in Alzheimer-type dementia.

The children of parents exposed to atomic bombs: estimates of the genetic doubling dose of radiation for humans

The data collected in Hiroshima and Nagasaki during the past 40 years on the children of survivors of the atomic bombings and on the children of a suitable control population are analyzed on the basis of the newly revised estimates of radiation doses. No statistically significant effects emerge with respect to eight different indicators. Since, however, it may confidently be assumed some mutations were induced, we have taken the data at face value and calculated the minimal gametic doubling doses of acute radiation for the individual indicators at various probability levels. An effort has also been made to calculate the most probable doubling dose for the indicators combined. The latter value is between 1.7 and 2.2 Sv. It is suggested the appropriate figure for chronic radiation would be between 3.4 and 4.5 Sv. These estimates suggest humans are less sensitive to the genetic effects of radiation than has been assumed on the basis of past extrapolations from experiments with mice.

Congenital malformations, stillbirths, and early mortality among the children of atomic bomb survivors: a reanalysis

Of all the data sets pertinent to the estimation of the genetic risks to humans following exposure to ionizing radiation, potentially the most informative is that composed of the cohort of children born to atomic bomb survivors. We present here an analysis of the relationship between parental exposure history and untoward pregnancy outcomes within this cohort, using to the fullest extent possible the recently revised estimates of the doses received by their parents, the so-called DS86 doses. Available for study are 70,073 terminations, but DS86 doses have not been or presently cannot be computed on the parents of 14,770. The frequency of untoward pregnancy outcomes, defined as a pregnancy terminating in a child with a major congenital malformation, and/or stillborn, and/or dying in the first 14 days of life, increases with combined (summed) parental dose, albeit not significantly so. Under a standard linear model, when the sample of observations is restricted to those children whose parents have been assigned the newly established DS86 doses (n = 55,303), ignoring concomitant sources of variation and assuming a neutron RBE of 20, the estimated increase per sievert in the predicted frequency of untoward outcomes is 0.00354 (+/- 0.00343). After adjustment for concomitant sources of variation, the estimated increase per sievert in the proportion of such births is 0.00422 (+/- 0.00342) if the neutron RBE is assumed to be 20. A "one-hit" model with appropriate adjustments for extraneous sources of variation results in an almost identical value, namely, 0.00412 (+/- 0.00364). When the sample is extended to include parents lacking the full array of dose parameters necessary to calculate the DS86 dose, but sufficient for an empirical conversion of the previously employed T65DR dose system to its DS86 equivalent, we find under the linear model that the estimated increase per sievert in untoward pregnancy outcomes is some 31% higher than that published previously, 0.00264 (+/- 0.00277), assuming an RBE of 20, after adjustment for extraneous sources of variation. (Since a dose could not be calculated in 367 of the 70,073 outcomes, the n = 69,706). The corresponding value with the one-hit model is 0.00262 (+/- 0.00294).

Radiation-related posterior lenticular opacities in Hiroshima and Nagasaki atomic bomb survivors based on the DS86 dosimetry system

This paper investigates the quantitative relationship of ionizing radiation to the occurrence of posterior lenticular opacities among the survivors of the atomic bombings of Hiroshima and Nagasaki suggested by the DS86 dosimetry system. DS86 doses are available for 1983 (93.4%) of the 2124 atomic bomb survivors analyzed in 1982. The DS86 kerma neutron component for Hiroshima survivors is much smaller than its comparable T65DR component, but still 4.2-fold higher (0.38 Gy at 6 Gy) than that in Nagasaki (0.09 Gy at 6 Gy). Thus, if the eye is especially sensitive to neutrons, there may yet be some useful information on their effects, particularly in Hiroshima. The dose-response relationship has been evaluated as a function of the separately estimated gamma-ray and neutron doses. Among several different dose-response models without and with two thresholds, we have selected as the best model the one with the smallest x2 or the largest log likelihood value associated with the goodness of fit. The best fit is a linear gamma-linear neutron relationship which assumes different thresholds for the two types of radiation. Both gamma and neutron regression coefficients for the best fitting model are positive and highly significant for the estimated DS86 eye organ dose.

Prenatal exposure to ionizing radiation and subsequent development of seizures

Seizures are a frequent sequela of impaired brain development and can be expected to affect more children with radiation-related brain damage than children without such damage. This report deals with the incidence and type of seizures among survivors prenatally exposed to the atomic bombing of Hiroshima and Nagasaki, and their association with specific stages of prenatal development at the time of irradiation. Fetal radiation dose was assumed to be equal to the dose to the maternal uterus. Seizures here include all references in the clinical record to "seizure," "epilepsy," or "convulsion." Histories of seizures were obtained at biennial routine clinical examinations starting at about the age of 2 years. These clinical records were used to classify seizures as febrile or unprovoked (without precipitating cause). No seizures were ascertained among subjects exposed 0-7 weeks after fertilization at doses higher than 0.10 Gy. The incidence of seizures was highest with irradiation at the eighth through the 15th week after fertilization among subjects with doses exceeding 0.10 Gy and was linearly related to the level of fetal exposure. This obtains for all seizures without regard to the presence of fever or precipitating causes, and for unprovoked seizures. When the 22 cases of severe mental retardation were excluded, the increase in seizures was only suggestively significant and only for unprovoked seizures. After exposure at later stages of development, there was no increase in recorded seizures.

Dental radiography exposure of the Hiroshima and Nagasaki populations

Dental radiography doses in Hiroshima and Nagasaki were estimated on the basis of survey data from dental hospitals and clinics in Hiroshima and Nagasaki, and doses were measured by thermoluminescent dosimeters and a phantom. Doses to organs, including the lens, pituitary fossa, thyroid gland, and skin were calculated from data obtained during a 2-week survey in both cities. The mean caput doses were calculated from the data indicating frequency per year and were tabulated by organs, age, teeth examined, type of examination, population, sex, and city. No significant difference was observed by age, population, sex, or city. Currently the doses incurred during dental radiography may not be sufficiently high to cause bias in the assessments for late radiation effects among atomic-bomb survivors. However, the mean caput thyroid doses of 62 mrad and 67 mrad in Hiroshima and Nagasaki, respectively, cannot be ignored from the standpoint of their potential in contributing to radiation-induced carcinogenesis.

Implications of the Hiroshima-Nagasaki genetic studies for the estimation of the human "doubling dose" of radiation

Since 1946 a continuous effort to evaluate the potential genetic effects of the atomic bombs has been sustained. Observations on children born in Hiroshima and Nagasaki include sex ratio, congenital malformations, stillbirths, survival of liveborn infants, chromosomal abnormalities (sex chromosomal abnormalities and balanced chromosomal rearrangements), mutations altering protein structure or activity, and physical growth and development. There are no statistically significant differences between the children of parents who received increased amounts of radiation at the time of the bombings and those whose parents did not. However, the difference between the two sets of children is consistent with the hypothesis of a genetic effect of the exposure, but its magnitude suggests humans are not as sensitive to the genetic effects of radiation as projected from the mouse paradigm.

Growth and differentiation of circulating hemopoietic stem cells with atomic bomb irradiation-induced chromosome abnormalities

The effects of atomic bomb irradiation on hemopoietic stem cells were studied cytogenetically using single colonies derived from hemopoietic progenitor cells. The subjects studied were 21 healthy atomic bomb survivors (10 males and 11 females) in the high dose exposure group (100+ rad) with a known high incidence (10% or more) of radiation-induced chromosome abnormalities in their peripheral blood lymphocytes (stimulated with phytohemagglutinin), and 11 nonexposed healthy controls (5 males and 6 females). Colony formation by circulating granulocyte-macrophage (GM-CFC) and erythroid (BFU-E) progenitor cells was made by the methylcellulose method using peripheral blood mononuclear cells. Chromosome specimens were prepared from single colonies by our micromethod. The total number of colonies analyzed in the exposed group was 131 for GM-CFC and 75 for BFU-E. Chromosome abnormalities were observed in 15 (11.5%) and 9 (12.0%) colonies, respectively. In the control group, the total number of colonies analyzed was 61 for GM-CFC and 41 for BFU-E. None of these colonies showed chromosome abnormalities. The difference in incidence of chromosome abnormalities was highly significant by an exact test; p = 0.003 for GM-CFC and 0.017 for BFU-E. The karyotypes of chromosome abnormalities obtained from the colonies in the exposed group were mostly translocations, but deletion and marker chromosomes were also observed. In two individuals, such karyotypic abnormalities as observed in the peripheral lymphocytes were also seen in the myeloid progenitor cells. This finding suggests that atomic bomb irradiation produced a chromosome aberration on multipotent hemopoietic stem cells common to myeloid and lymphoid lineages. These stem cells, although carrying chromosome defects, are likely to have survived for more than 30 years, continuously producing progenitor cells capable of normal-looking growth and differentiation.

Increased somatic cell mutant frequency in atomic bomb survivors

Frequencies of mutant T-cells in peripheral blood, which are deficient in hypoxanthine guanine phosphoribosyltransferase (HPRT) activity, were determined for atomic bomb survivors by direct clonal assay using a previously reported method (Hakoda et al., 1987). Results from 30 exposed survivors (more than 1 rad exposed) and 17 age- and sex-matched controls (less than 1 rad exposed) were analyzed. The mean mutant frequency (Mf) in the exposed (5.2 X 10(-6); range 0.8-14.4 X 10(-6)) was significantly higher than in controls (3.4 X 10(-6); range 1.3-9.3 X 10(-6)), which was not attributable to a difference in non-mutant cell-cloning efficiencies between the 2 groups, which were virtually identical. An initial analysis of the data did not reveal a significant correlation between individual Mfs and individual radiation dose estimates when the latter were defined by the original, tentative estimates (T65D), even though there was a significant positive correlation of Mfs with individual frequency of lymphocytes bearing chromosome aberrations. However, reanalysis using the newer revised individual dose estimates (DS86) for 27 exposed survivors and 17 controls did reveal a significant but shallow positive correlation between T-cell Mf values and individual exposure doses. These results indicate that HPRT mutation in vivo in human T-cells could be detected in these survivors 40 years after the presumed mutational event.

Learning disabilities in individuals exposed prenatally to ionizing radiation: the Hiroshima and Nagasaki experiences

The brain, undoubtedly the most complex organ in the mammalian body, is the culmination of a long and interrelated sequence of molecular, cellular and tissue events. Brain function hinges on the orderly progression of these, each of which must occur correctly, temporally and spatially. Impingement on any one will give rise to a less developed system of cellular connections, and hence impaired function. Moreover, the neurons of the central nervous system are not self-renewing and thus neuronal loss cannot be repaired through repopulation. Reanalysis of the data on the prenatally exposed survivors of the atomic bombing of Hiroshima and Nagasaki suggests that severe mental retardation occurs primarily, if not exclusively in the period from the 8th through the 15th week following fertilization. Within this window of vulnerability, the increase in mental retardation appears linear with dose and without threshold. More subtle functional effects also occur as reflected in diminished performance on intelligence tests and in school. These findings and their implications for space travel and regulatory agencies charged with the specification of acceptable risks should not require further elaboration in this article given the focus of the radiobiological presentations at this meeting.

The analysis of chromosomally aberrant cells based on beta-binomial distribution

Analysis carried out here generalized on earlier studies of chromosomal aberrations in the populations of Hiroshima and Nagasaki, by allowing extrabinomial variation in aberrant cell counts corresponding to within-subject correlations in cell aberrations. Strong within-subject correlations were detected with corresponding standard errors for the average number of aberrant cells that were often substantially larger than was previously assumed. The extrabinomial variation is accommodated in the analysis in the present report, as described in the section on dose-response models, by using a beta-binomial (beta-B) variance structure. It is emphasized that we have generally satisfactory agreement between the observed and the beta-B fitted frequencies by city-dose category. The chromosomal aberration data considered here are not extensive enough to allow a precise discrimination between competing dose-response models.

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.

Ophthalmologic changes related to radiation exposure and age in adult health study sample, Hiroshima and Nagasaki

A 2-year ophthalmologic study of age and radiation-related ophthalmologic lesions among the atomic bomb survivors in Hiroshima and Nagasaki was conducted in 1978-80. The study sample in both cities was composed of all persons exposed to 100+ rad, their controls, and all other persons with a previous record of axial opacities or posterior subcapsular changes. Most of the losses were due to persons who refused to participate or for whom it was not possible to arrange for an ophthalmologic examination at the time of the regularly scheduled medical examination. It should be emphasized, however, that the loss of persons in both the control and the 100+ rad groups did not change systematically with increasing age by city. Increased lenticular opacities, other lens changes, and loss of visual acuity and accommodation occurred with increasing age in both exposed and control subjects as manifestations of the normal aging process. A highly significant excess risk for all age categories in the 300+ rad group in comparison to those in the control group was observed for both axial opacities and posterior subcapsular changes in Hiroshima, but not in Nagasaki. A stronger radiosensitive aging effect for persons who were under 15 years old at the time of the bombing (ATB) was observed for both axial opacities and posterior subcapsular changes in Hiroshima.

Glycogen storage disease type 1b: microsomal glucose-6-phosphatase system in two patients with different clinical findings

The basic defect in glycogen storage disease (GSD) type 1b was investigated in two patients: one, (Y.S.), a severely affected infant and the other, (Y.M.), an adult with mild clinical symptoms. The enzymatic studies on liver needle biopsy specimens from the two patients indicated that glucose-6-phosphate (G-6-P) phosphohydrolase activity of the "intact microsomes" was partially deficient (20% of that in controls) in Y.M. and undetectable in Y.S. Activities of G-6-P phosphohydrolase in the disrupted microsomes of Y.S. and Y.M. are higher than those in the disrupted microsomes of controls (12.60 mumole/min/g liver in Y.S., 9.18 in Y.M. and 6.26 +/- 1.22, mean +/- S.D. in controls). Our study also shows that PPi phosphohydrolase activities of the "intact microsomes" from both patients (6.07 mumol/min/g liver in Y.S. and 5.36 in Y.M.) were greater than those of the controls (3.23 +/- 0.77 mumole/min/g wet weight liver). These results indicate that the G-6-P translocase was the locus of the defect in both patients with GSD type 1b. Clinical symptoms and enzymatic studies suggest that the clinical severity of this disorder depends on the level of residual activities of G-6-P translocase. Kinetic studies showed an abnormally high Km of the residual G-6-P translocase in Y.M., suggesting a structural gene mutation. The systematic assay method for glucose-6-phosphatase system, which requires only 15 mg of liver tissues, is also described.

Glycogen storage disease type 1b due to a defect of glucose-6-phosphate translocase

Patients with glycogen storage disease (GSD) type 1b have shown normal activity of glucose-6-phosphatase (EC 3.1.3.9) as assayed in frozen liver, though their clinical and biochemical findings were similar to those of patients with GSD 1a (McKusick 23220) (Senior and Loridan, 1968). In 1978, we suggested that a basic defect of GSD 1b exists in the glucose-6-phosphate (G6P) transport system (Narisawa et al., 1978; Igarashi et al., 1979). Since then, there have been reports confirming our observation (Beaudet et al., 1980; Lange et al., 1980; Corbeel et al., 1981; Schaub et al., 1981). Recently, it was postulated that the G6Pase system contains a phosphate translocase which mediates the efflux of phosphate, in addition to a G6P translocase and a non-specific phosphohydrolase (Arion et al., 1980). Therefore, it is possible that GSD 1b is caused by a defect of phosphate translocase. In this paper, the basic defect in GSD type 1b was investigated in two patients; one with severe, the other with mild, clinical symptoms.

Genetic effects of the atomic bombs: a reappraisal

Data are presented on four indicators of genetic effects from studies of children born to survivors of the atomic bombings of Hiroshima and Nagasaki. The indicators are frequency of untoward pregnancy outcomes (stillbirth, major congenital defect, death during the first postnatal weak); occurrence of death in live-born children, through an average of life expectancy of 17 years; frequency of children with sex chromosome aneuploidy; and frequency of children with mutation resulting in an eletrophoretic variant. In no instance is there a statistically significant effect of parental exposure; but for all indicators the observed effect is in the direction suggested by the hypothesis that genetic damage resulted from the exposure. On the basis of assumptions concerning the contribution that spontaneous mutation in the preceding generation makes to the indicators in question, it is possible to estimate the genetic doubling dose for radiation for the first three indicators (the data base is still too small for the fourth). The average of these estimates is 156 rems. This is some four times higher than the results from experimental studies on the mouse with comparable radiation sources, which have been the principal guide to the presumed human sensitivities. The relevance of these data in setting permissible limits for human exposures is discussed briefly.

Immunoglobulin E (IgE) multiple myeloma: a case report and review of the literature

A case of immunoglobulin E (IgE) myeloma with clinical features of "classic" myeloma is presented. Skeletal roentgenograms showed osteoporosis and compression fractures of the vertebrae but no osteosclerosis. Protein analyses revealed an M component of the IgE kappa type with a concentration of 3.1 g/dl. Although morphologic examination revealed that the plasma cells were not so differentiated, well-developed Golgi apparatus and abundant rough-surfaced endoplasmic reticulum were observed. An indirect immunofluorescence technique showed characteristic apple green fluorescence. The E myeloma protein of our patient had no antibody activity. Treatment with melphalan or cyclophosphamide resulted in a decrease in the serum IgE level and in the level of Bence Jones protein in the urine. The clinical and laboratory features of IgE myeloma were summarized and compared with those of other classes of myeloma.

Search for mutations affecting protein structure in children of atomic bomb survivors: preliminary report

A total of 289,868 locus tests, based on 28 different protein phenotypes and using one-dimensional electrophoresis to detect variant proteins, has yielded one probable mutation in the offspring of "proximally exposed" parents, who received an estimated average gonadal exposure of 31 to 39 rem in the atomic bombings of Hiroshima and Nagasaki. There were no mutations in 208,196 locus tests involving children of "distally exposed" parents, who had essentially no radiation exposure.