Journal of Radiation Research
Online ISSN : 1349-9157
Print ISSN : 0449-3060
Volume 33, Issue 4
Displaying 1-9 of 9 articles from this issue
  • YASUYUKI KURIHARA, MATI RIENKJKARN, HISAMI ETOH
    1992 Volume 33 Issue 4 Pages 267-274
    Published: December 15, 1992
    Released on J-STAGE: May 29, 2006
    JOURNAL FREE ACCESS
    The adaptive response was examining chromosomal aberrations and micronucleus in cultured fish cells, ULF-23 (mudminnow) and CAF-31 (gold fish). When cultured fish cells were first irradiated with small doses of X-rays, they became less sensitive to subsequent exposures to high doses. The effective adaptive dose was 4.8 cGy- 9.5 cGy. Adaptive doses given cells in the G1 phase were more effective than when given in the S phase. The adaptive response was maximal at 5 hours and disappeared at 10 hours after the adaptive dose. The expression of the response was inhibited by treatment with 3-aminobenzamide, as reported for mammalian cells, and with arabinofuranoside cytosine, an inhibitor of DNA polymerase alpha. Caffeine, an inhibitor of post-replicational repair, had no effect on the response.
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  • MINORU INOUYE, SHIZU HAYASAKA, ATSUSHI FUNAHASHI, HIDEKI YAMAMURA
    1992 Volume 33 Issue 4 Pages 275-281
    Published: December 15, 1992
    Released on J-STAGE: May 29, 2006
    JOURNAL FREE ACCESS
    Morphological changes in Bergmann glial fibers in the developing cerebellar cortex produced by exposure to gamma-rays were investigated in association with ectopic granule cells. Six-day-old mice that had been exposed to 3 Gy of gamma-radiation were killed 6 hours after exposure or at 7 through 30 days of age. Their cerebella were examined histologically and immunohistochemically for glial fibrillary acidic protein in Bergmann fibers. Extensive cell death took place in the external granular layer (EGL) of the cerebellum from 6 through 24 hours after exposure. This led to the thinning of the EGL and a decrease in the number of migrating cells in the molecular layer. The number of Bergmann cells was not decreased, but the fibers in the molecular layer were distorted; whereas, in the control these fibers were straight and perpendicular to the pial surface. The EGL began to recover 2 days after exposure, and abnormally oriented migrating cells were seen. At 17 days of age, some cell clustering was observed in the molecular layer of the irradiated cerebellum. Distortion of the Bergmann fibers was marked in regions where ectopic granule cells appeared at 30 days of age. These findings suggest that the distortion of Bergmann fibers leads to the production of ectopic granule cells after exposure to gamma-radiation.
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  • ASHOK KUMAR, HIROSHI KIMURA, TAKASHI AOYAMA, TSUTOMU SUGAHARA
    1992 Volume 33 Issue 4 Pages 282-289
    Published: December 15, 1992
    Released on J-STAGE: May 29, 2006
    JOURNAL FREE ACCESS
    The effect of solcoseryl on the growth, radiosensitization and ability of V79 cells to recover from X-ray-induced damage has been observed. Solcoseryl at 0.8 mg/ml was the optimal concentration for the stimulation of cell growth. Increased sensitivity to X-irradiation was found in the shoulder region of V79 cells treated before and after irradiation with solcoseryl (0.8 mg/ml). The Dq and extrapolation number (n) decreased. Solcoseryl treatment apparently does not reduce split dose recovery or inhibit the repair of potentially lethal damage. Flow cytofluorometry studies of the cell cycle distribution and mitotic index show that solcoseryl inhibits the expression of radiation-induced cell arrest in the G2 phase of the cell cycle. Although this action increases radiation sensitization, additional mechanisms probably exist.
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  • HISAMASA JOSHIMA, HIROSHI OHARA, YOSHIRO AOKI
    1992 Volume 33 Issue 4 Pages 290-300
    Published: December 15, 1992
    Released on J-STAGE: May 29, 2006
    JOURNAL FREE ACCESS
    OK-432, a multicytokine inducer and clinically used as an immunopotentiating anti-cancer agent, is known to induce IL-1 and TNF-α The suppressive effect of IL-1 and TNF-α on erythropoiesis could limit the clinical use of OK-432 in cancer treatment, especially when combined with radiotherapy. In this study, the effect of OK-432 on normal and X-ray impaired erythropoiesis was examined. C57BL/6J mice were injected with a single dose of OK-432 (5.0 KE). Erythropoietic activity was measured by 59Fe incorporation into circulating erythrocytes and the heme iron fraction of erythropoietic tissue.
    When irradiated with 662 cGy of X-rays, OK-432 prolonged the survival of mice. No significant change in erythropoiesis was observed when normal mice were treated with OK-432. When treated with OK-432, the recovery of erythropoiesis after irradiation was promoted as judged by the uptake of 59Fe into erythrocytes. This promotion was observed when OK-432 was injected within 1 day before or within 3 hours after the irradiation with 284 cGy of X-rays. This promoting effect, however, appeared to be limited to the spleen. Whether the combination of OK-432 with radiotherapy has the potential to improve the treatment of malignant tumors is still a subject of controversy. The present results, nevertheless, suggest that when combined with radiotherapy, OK-432, at the very least, may have no adverse effects on erythropoiesis.
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  • SENTARO TAKAHASHI, HIROSHI SATO, YOSHIHISA KUBOTA, JIRO INABA
    1992 Volume 33 Issue 4 Pages 301-308
    Published: December 15, 1992
    Released on J-STAGE: May 29, 2006
    JOURNAL FREE ACCESS
    The 239Pu distribution in the 12.5-day-old rat conceptus was compared between in vivo and in vitro experimental systems to establish a possible mechanism of cross-palcental transfer of this radionuclide. In the in vivo study, plutonium citrate solution was injected intravenously to pregnant Wistar rats. In the in vitro study, either plutonium citrate or plutonium hydroxide colloid was administered, as a solution of Eagle MEM and FCS containing 239Pu at the concentration used in the maternal serum in the in vivo experiments, to rat conceptuses maintained by the whole-embryo culture method. The concentration of 239Pu in the yolk sac (239Pu activity per gram wet weight) were much higher than in the embryo in both the in vivo and in vitro experiments, suggesting that the yolk sac may be an effective barrier against the transfer of plutonium to the embryos. The ratios of the 239Pu concentration in the yolk sac to that in the embryo were relatively constant with time after administration in the in vitro system; 18-27 for plutonium citrate and 67-84 for plutonium hydroxide. In the in vivo experiment, these ratios changed with time after injection; 15 at 5 min and 62 and 60 min after injection. This suggests that in the in vivo system, the chemical form of 239Pu changed with time after injection, probably to a macromolecular form such as the hydroxide colloid or plutonium-protein complex although 239Pu was injected to the maternal blood as citrate.
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  • HIROSHI TAKEDA, TETSUO IWAKURA
    1992 Volume 33 Issue 4 Pages 309-318
    Published: December 15, 1992
    Released on J-STAGE: May 29, 2006
    JOURNAL FREE ACCESS
    The incorporation and distribution of tritium were examined in rats exposed to tritiated rice or tritiated soybean by single ingestion or continuous feeding. Results were compared with those for tritiated wheat and tritiated water in a previous study done under the same experimental conditions. All the tritiated crops examined were more efficiently incorporated into rat tissues than was tritiated water, the extent of incorporation depending on the kind of crop. The differences in incorporation were clear in organically bound tritium determined as tritium in dried tissue. The respective concentrations of organically bound tritium after a single ingestion of tritiated rice, tritiated wheat or tritiated soybean were about 10-20, 20-30 and 25-60 times higher than after the ingestion of tritiated water. After continuous feeding for 22 days with tritiated rice, tritiated wheat or tritiated soybean, the respective concentrations of organically bound tritium were 5-8, 6-11 and 10-25 times the values after continuous ingestion of tritiated water. At the end of continuous ingestion, the radiation dose rates to almost of the tissues from all three tritiated crops were estimated to be 2-3 times that for tritiated water.
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  • YUMIKO NITTA, KENJI KAMIYA, KENJIRO YOKORO
    1992 Volume 33 Issue 4 Pages 319-333
    Published: December 15, 1992
    Released on J-STAGE: May 29, 2006
    JOURNAL FREE ACCESS
    C57BL/6N×XC3H/He F1 mice were exposed in utero to 0, 1.0 and 2.7 Gy of 252Cf or 60Co at day 16.5th of gestation. Mice of both sexes were observed for 2 years. The females in the irradiated groups showed increases in the incidences of pituitary, mammary gland, liver and lung tumors. 252Cf was more effective in inducing tumors than was 60Co. Interestingly, the incidence of hematopoietic tumors decreased by irradiations with 252Cf but not with 60Co. The incidences of liver tumors in males increased by 252Cf-irradiation, whereas, the incidences of skin and soft tissue tumors increased by 60Co-irradiation. These results indicate that irradiation in utero during the late embryonic stage can induce tumors postnatally after a long latency. Moreover, females irradiated in utero had disfunction of the ovaries, evidence of impairment of the female''s specific hormonal environment. This may be the cause of the low incidence of ovarian tumors and the high incidences of liver, lung and pituitary tumors in these female mice. Females with pituitary tumors had a high serum prolactin, which might be responsible for the concurrence of mammary gland tumors. These results indicate the importance of host factors in the development of radiation-induced tumors.
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  • YOICHI OGHISO, YUTAKA YAMADA
    1992 Volume 33 Issue 4 Pages 334-341
    Published: December 15, 1992
    Released on J-STAGE: May 29, 2006
    JOURNAL FREE ACCESS
    Previous studies suggest that the radiosensitivity and origin of tissue macrophage precursors differ from those of hemopoietic macrophage colony-forming units (CFU-Ms) committed to macrophage-lineage cells. We assessed the origins of tissue macrophage colony-forming cells (M-CFCs) in mice by comparing their kinetics and radiosensitivities in the normal steady state and under the conditions of bone marrow depletion by 89Sr-administration and/or splenectomy. The results indicate that the radiosensitive peritoneal M-CFCs elicited by thioglycollate are derived from bone marrow macrophage precursors; where as alveolar M-CFCs, which are radioresistant, are self-sustained locally and independent of hemopoietic macrophage precursors. In contrast, highly radiosensitive liver M-CFCs are probably derived from CFU-Ms that appear to be propagated in the spleen in association with hemopoietic responses.
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  • HIROFUMI NAKATSUKA, YUKIKO SHIMIZU, TSUTOMU YAMAMOTO, ICHIRO SEKINE, H ...
    1992 Volume 33 Issue 4 Pages 342-361
    Published: December 15, 1992
    Released on J-STAGE: May 29, 2006
    JOURNAL FREE ACCESS
    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 104 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.
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