著者

田中 公夫 鎌田 七男 大北 威 蔵本 淳

出版者

日本放射線影響学会

雑誌

Journal of Radiation Research (ISSN:04493060)

巻号頁・発行日

vol.24, no.4, pp.291-304, 1983-12

被引用文献数

1 25

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The distribution of breakpoints within chromosomes in lymphocytes of 39 healthy atomic bomb survivors who were heavily exposed were studied by means of G- and Q-banding techniques. A total of 1,414 breakpoints in 651 cells with structural chromosome aberrations were used for the present analyses. The results obtained were as follows: (1) In chromosomes #15, #18 and #22, the breaks were more frequently observed than expected. On the contrary, the number of breaks among chromosomes #1, #2 and X was less than expected. (2) A higher incidence of breakpoints according to the length of regions in 4q3, 5q3 and 14q3 and a lower incidence in regions around centromeres of large chromosomes were observed. (3) Distribution of breakpoints was 26.6% in the centromeric region, 30.8% in the middle region and 42.6% in the telomeric region. (4) Seventy-four percent of the breaks was observed in the negative bands.

著者

熊谷 エツ子 田中 龍二 熊谷 崇 東田 善治 尾道 三一 中村 郁夫 田上 省三 甲木 孝人 澤田 昭三

出版者

日本放射線影響学会

雑誌

Journal of Radiation Research (ISSN:04493060)

巻号頁・発行日

vol.29, no.3, pp.203-210, 1988-09

被引用文献数

1 1

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To clarify the long-term effects of occupational exposure to low doses of radiation, Epstein-Barr virus (EBV)-specific antibody titers in sera from 104 radiological technologists (R.T.) and 118 controls in Kumamoto prefecture were measured by the immunofluorescence method. Antibody titers to viral capsid antigen (VCA)-IgG increased with the years of experience as R.T., and the prevalence of abnormal antibody titers to both VCA-IgG and early antigen (EA)-IgG were significantly higher in R.T. with over 15 years of experience or 30 rads of cumulative radiation dose than in the controls. However, there was no correlation between exposure and the frequency of abnormal EBV-associated nuclear antigen (EBNA) antibody titers. The EBY-specific antibody titers of 24 Hiroshima atomic-bomb survivors were also measured. They were similar to those of the R.T.with over 30 years of experience. The EBV-specific antibody titers of R.T. suggest that there may be an impairment of immunologic competence after continuous long-term exposure to low doses of radiation. Also, the correlation of EBV-specific antibody titers and frequency of cells with chromosome aberrations in 53 R.T. was studied. Some correlations were found between the antibody titers to both of the VCA-IgG and EBNA and the frequency of cells with chromosome aberrations.

著者

渡辺 敦光 岡本 太郎 山田 和正 安東 保海 伊藤 明弘 星 正治 澤田 昭三

出版者

日本放射線影響学会

雑誌

Journal of Radiation Research (ISSN:04493060)

巻号頁・発行日

vol.34, no.3, pp.235-239, 1993-09

被引用文献数

2 2

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The effects of the dose rate and the energy of fission neutrons using an iron block on tumorigenesis in B6C3F1 mice were examined. Six-week-old female animas were divided into 4 groups and exposes to ^<252>Cf neutron irradiation at dose rates of 0.05 cGy/min, with (Group 1) or without (Group 2) filtering through a 10 cm thick iron block, 0.8 cGy/min (Group 3) or 0 (Group 4 controls). Total neutron exposure was 50 cGy in each of groups 1-3 and total irradiation dose was 56,75 and 75 cGy in Groups 1-3, respectively. Total tumor incidences or multiplicity were significantly higher in Group 3 than in Group 1. A similar tendency was observed as compared to Group 2, ovarian and Harderian gland tumors being mainly affected and adrenal tumors were significantly higher in Group 2 than in Group 1. The results indicated a clear increase in tumorigenesis with the higher dose rate and no filtering influence of iron was evident, despite the drop in neutron energy level.

著者

佐伯 誠道 小柳 卓 田中 義一郎 富川 昭男

出版者

日本放射線影響学会

雑誌

Journal of Radiation Research (ISSN:04493060)

巻号頁・発行日

vol.5, no.2, pp.120-123, 1964-06

被引用文献数

1

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Mesurements were made on the ^<90>Sr content in human bone samples from subjects who died during the period from 1961 to October 1963 in Japan. The most remarkable accumulation of ^<90>Sr in human bone was found in 0-4 year age group. Considerable increases with time in the S. U. (^<90>Sr pc/g Ca) value was also found in this group.

著者

津郷 友吉 野崎 博 浅利 民弥 山県 登

出版者

日本放射線影響学会

雑誌

Journal of Radiation Research (ISSN:04493060)

巻号頁・発行日

vol.5, no.2, pp.131-137, 1964-06

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In succession of the previous report (1), the measurements of strontium-90 (Sr-90), cesium-137 (Cs-137) and iodine-131 (I-131) concentrations in milk were carried out in order to evaluate the range of the radioactive contamination of milk in Japan since 1961. Farm milks collected from various districts of Japan monthly from 1961 to 1963 were used for radioactivity assay. The results of observation show the Sr-90 concentration in milk is higher than that in the previous years (1957-1960) all over the country and there is regional variation in Sr-90 and Cs-137 concentrations.

著者

永田 弘治 菅原 努 田中 富蔵

出版者

日本放射線影響学会

雑誌

Journal of Radiation Research (ISSN:04493060)

巻号頁・発行日

vol.13, no.3, pp.163-166, 1972-09

被引用文献数

1 31

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A new sulfhydryl compound, 2-mercaptopropionylglycine, which is commercially available in Japan as a detoxicating agent, has been shown to be protective in mice against lethal doses of ionizing radiation at a very low dose of 20 mg/kg, far below its toxic dose of more than 2,000 mg/kg. The drug has an optimum dose for protection, 20 mg/kg, and its protection continues more than 3 hours, though with a less extent after 1 hour than within 1 hour. The results suggest a clue on the mechanism of sulfhydryl radioprotectors and give promise of clinical application.

著者

HIGO KEN-ICHI YAMAMOTO OSAMU

出版者

日本放射線影響学会

雑誌

Journal of Radiation Research (ISSN:04493060)

巻号頁・発行日

vol.26, no.3, pp.353-359, 1985-09

被引用文献数

2

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In the presence of tritiated water (HTO), Escherichia coil NG30 was grown in sealed test tubes containing synthetic medium (M9-0.4% glucose-0.005% arginine), and cell growth was monitored by measuring medium turbidity. Catalase (60 μg/ml) was added to the medium to reduce HTO associated accumulation of H_2O_2. A positive correlation between increasing concentration of HTO in the medium and the growth suppression was seen. A similar trend was observed when cells were grown under continuous irradiation of ^<60>Co gamma-rays. The RBE of HTO beta-rays relative to gamma-rays was calculated from the accumulated doses to the cultures. It was found to be 1.7 when the growth was inhibited to 60% of the control, and increased with decreasing dose.

著者

松田 日吉 増田 高広 近藤 正春

出版者

日本放射線影響学会

雑誌

Journal of Radiation Research (ISSN:04493060)

巻号頁・発行日

vol.6, no.1, pp.45-53, 1965-03

被引用文献数

2

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Kinetic investigations for reduction of cytochrome c in aqueous solution induced by cobalt-60 gamma rays have been carried out. Initial reduction yield of cytochrome c is about 5 as limiting value. The decrease in initial reduction yield in presence of thallous ion as a radical scavenger with ferricytochrome c provides some evidences that OH radicals can contribute to reduction through some possible intermediate. The effects of concentration ratio in ferro-ferricytochrome c and thallous ion-ferricytochrome c systems on initial reduction yield were investigated. The results can be explained on the basis of some reaction scheme based on the contribution of OH radicals to reduction of ferricytochrome c. The following rate constants were determined by kinetic treatment of the results. k_<OH+RH2Fe1+>=5×10^<10>M^<-1>sec^<-1> k_<OH+RH2Fe2+>=4.1×10^<10>M^<-1>sec^<-1>.

著者

松坂 尚典 SAKAMOTO HIDEKI SATO ITARU SHINAGAWA KUNIHIRO KOBAYASHI HARUO NISHIMURA YOSHIKAZU

出版者

日本放射線影響学会

雑誌

Journal of radiation research (ISSN:04493060)

巻号頁・発行日

vol.36, no.3, pp.196-202, 1995-09

被引用文献数

2

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Whole-body retention and fetal uptake of ^<65>5Zn under a Zn-deficient diet were studied in pregnant mice in the late gestational stage after a single oral administration of ^<65>Zn. Whole-body retentions were much greater in mice given a Zn-deficient diet than in those given a Zn-normal diet. Accordingly, the amount of ^<65>Zn transmitted to the offspring in utero was greater in the Zn-deficient diet group. In another experiment, fetal uptake of ^<65>Zn in dams on gestation day 17 was examined over a period of 24 hr after a single intravenous administration of ^<65>Zn to the Zn-deficient and Zn-normal animals. There was no major difference in fetal uptake between the two groups, indicative that approximately a similar proportion of the ^<65>Zn retained in the maternal body was transmitted to the in utero offspring in both groups.

著者

AUDA H. KHALEF Z.

出版者

日本放射線影響学会

雑誌

Journal of Radiation Research (ISSN:04493060)

巻号頁・発行日

vol.23, no.2, pp.141-149, 1982-06

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The kinetics of degradation and synthesis of DNA and the nature of radioactive substances released from M. radiodurans R_<11>5 labeled with thymidine-methyl-^3H after UV and gamma irradiations were investigated. The release of labeled material from the DNA began immediately upon incubation and terminated in due time 90 min and 180 min for UV and gamma irradiations, respectively. When acriflavine was added to the medium, post-irradiation degradation process did not terminate even after 9 h in the case of UV exposure. However, it terminated after 6 h in the case of gamma irradiation. In the presence of acriflavine, DNA synthesis resumed after termination of DNA degradation in the case of gamma irradiation and this was not observed in the case of UV irradiation. Degradation products were chromatographed and it was found that they were located in one major radioactive peak. However their locations were different for UV and gamma radiations. For UV irradiation, the peak fell in the thymine region, while for gamma irradiation it fell in the thymidine region.

著者

FUJIMOTO KENZO YONEHARA HIDENORI YAMAGUCHI YASUHIRO ENDO AKIRA

出版者

日本放射線影響学会

雑誌

Journal of Radiation Research (ISSN:04493060)

巻号頁・発行日

vol.42, pp.85-93, 2001-12

被引用文献数

1 4

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The NIRS staff interviewed the residents in the evacuated zone around the JCO facility in Tokai-mura on 19 and 20 November, 1999, to obtain the following parameters every 30 minutes starting from 10:35 A.M. on 30 September to 6:15 A.M. on 1 October: the distance from the precipitation tank, the type of the house, positions in the house, wall materials and their thickness in order to estimate individual doses due to the accident. The ambient dose equivalents were obtained based on monitoring data during the accident. In addition, computer calculations were conducted to evaluate the conversion factor from ambient dose equivalent to effective dose equivalent as well as the shielding effect of the house or factory to estimate the effective dose equivalent to the residents. The estimated individual doses based on the behavior survey were in the range from zero to 21mSv. The individual doses were reported to the residents during the second visit to each house and factory at the end of January, 2000.

著者

Wang Bing

出版者

日本放射線影響学会

雑誌

Journal of radiation research (ISSN:04493060)

巻号頁・発行日

vol.42, no.1, pp.1-10, 2001-03

被引用文献数

17 37

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The irradiation of fetuses at the late period of organogenesis has been known to induce a dramatic increase in malformations. The mechanisms involved, however, have remained unclear for a long time. Using the mouse limb bud system, we first found that radiation-induced apoptosis is involved in the malformation, namely, radiation-induced apoptosis in the predigital regions of embryonic limb buds is responsible for digital defects in mice. An examination of embryonic C57BL/6J mice with different p53 (trp53) status enabled us to further find that susceptibility to radiation-induced apoptosis in the predigital regions and digital defects depend on both the p53 status and the radiation dose; p53 wild-type mice appeared to be the most sensitive, while p53 knockout mice were the most resistant. These results indicate that p53-dependent apoptosis mediates radiation-induced digital defects in the later organogenesis period. The existence of a radioadaptive response in embryonic mice, which has not been reported so far, was found by irradiating embryos with either 5 cGy or 30 cGy on embryonic day 11 prior to a challenging irradiation at 3 Gy on embryonic day 12. p53-heterozygous embryos did not show the radioadaptive response, indicating the involvement of p53 in the radioadaptive response in embryogenesis.

著者

Nair Cherupally K.K. Parida Dillip K. Nomura Taisei

出版者

日本放射線影響学会

雑誌

Journal of radiation research (ISSN:04493060)

巻号頁・発行日

vol.42, no.1, pp.21-37, 2001-03

被引用文献数

38 321

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Radiotherapy is the most common modality for treating human cancers. Eighty percent of cancer patients need radiotherapy at some time or other, either for curative or palliative purpose. To obtain optimum results, a judicious balance between the total dose of radiotherapy delivered and the threshold limit of the surrounding normal critical tissues is required. In order to obtain better tumor control with a higher dose, the normal tissues should be protected against radiation injury. Thus, the role of radioprotective compounds is very important in clinical radiotherapy. Ionizing radiation causes damage to living tissues through a series of molecular events, such as photoelectric, Compton and Auger effects, depending on the radiation energy. Because human tissues contain 80% water, the major radiation damage is due to the aqueous free radicals, generated by the action of radiation on water. The major free radicals resulting from aqueous radiolysis are OH, H, e_<aq>^- , HO_2, H_ 3 O^+ , etc. These free radicals react with cellular macromolecules, such as DNA, RNA, proteins, membrane, etc, and cause cell dysfunction and mortality. These reactions take place in tumor as well as normal cells when exposed to radiation. The radiation damage to a cell is potentiated or mitigated depending on several factors, such as the presence of oxygen, sulfhydryl compounds and other molecules in the cellular milieu. In the presence of oxygen, hydrated electrons and H atoms react with molecular oxygen to produce radicals, such as HO_2 , O_2^- , apart from other aqueous free radicals. The increase in the sensitivity of cells to ionizing radiation in the presence of oxygen, compared to that in its absence, is called the oxygen effect. The ratio of the dose required to achieve a given cell survival in the absence of oxygen to the dose required for the same effect under fully oxygenated conditions is called the oxygen enhancement ratio (OER), the value of which varies between 2.5 - 3 for X- and gamma- radiation. The effect of oxygen is said to be dose modifying and is independent of the radiation dose. Oxidative damage to the cellular genetic material, i.e., DNA, plays a major role in mutagenesis and carcinogenesis. Highly reactive oxygen radicals produced by ionizing radiation cause lesions in DNA which lead to cell killing and mutations. Enzymes such as superoxide dismutase, glutathione peroxidase and catalase protect mammalian cells from oxidative radiation damage7). It was recently reported that a cell line derived from a mutant strain of mouse having low cellular levels of temperature sensitive catalase activity is more sensitive to radiation and hydrogen peroxide.

著者

小室 正人

出版者

日本放射線影響学会

雑誌

Journal of Radiation Research (ISSN:04493060)

巻号頁・発行日

vol.17, no.2, pp.99-105, 1976-06

被引用文献数

1

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The process of ovarian tumorigenesis in ddY/F and C3H/TW mice was studied at various times until 18 months after whole body irradiation with a single dose of 130R or 260 R of X-rays. The first ovarian tumors were observed at 9 months after irradiation in ddY/F mice. In a total of 28 of 71 ddY/F mice, 33 ovarian tumors were developed, which were subdivided to 25 luteomas, 4 granulosa-cell tumors, one mixed cell tumor and 3 tubular adenomas. On the other hand, 21 of 29 C3H/TW mice had altogether 32 tubular adenomas and one mixed cell tumor. At older ages, small interstitial cells with eosinophilic cytoplasm were observed in irradiated ovaries. The cells resembled luteoma cells. Luteoma may be derived from the small interstitial cells. Since the earlier works by Parkes, Brambell et al. , it has been well documented that mammalian ovaries are very sensitive to radiation in all stages of postnatal life. Furth and Furth, Upton et al. reported that ovarian tumors developed in mice at more than 7-10 months after irradiation at 5-12 weeks of age.