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Volume 36 (1995)
- Issue 4 Pages 239-
- Issue 3 Pages 171-
- Issue 2 Pages 77-
- Issue 1 Pages 1-
Volume 36, Issue 2
Displaying 1-7 of 7 articles from this issue
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L. G. COCKERHAM, C. D. FORCINO1995 Volume 36 Issue 2 Pages 77-90
Published: June 15, 1995
Released on J-STAGE: March 28, 2006
JOURNAL FREE ACCESSExposure to ionizing radiation causes hypotension, cerebral ischemia and release of histamine (HA) and serotonin (5-HT). To investigate the relationship among these responses, rhesus monkeys (Macaca mulatta) received physiological saline (i.v.), disodium cromoglycate (DSCG), antihistamines (AH, mepyramine and cimetidine), or methysergide (METH), then were given 25 Gy whole-body irradiation. Monkeys receiving DSCG, AH or METH had higher post-irradiation mean arterial blood pressure (MBP) than saline-treated controls. Compared to levels in controls, post-irradiation hippocampal blood flow (rCBF) levels were higher in monkeys receiving DSCG, AH or METH. Treatment with the 5-HT2 receptor antagonist methysergide was the most effective in maintaining both rCBF and MBP after irradiation. Results support the hypothesis that the irradiation-induced cerebral ischemia and, to some extent, the hypotension is mediated by serotonin through 5-HT2 receptor sites.View full abstractDownload PDF (684K) -
S. ENDO, M. HOSHI, H. TAUCHI, S. TAKEOKA, K. KITAGAWA, S. SUGA, N. MAE ...1995 Volume 36 Issue 2 Pages 91-102
Published: June 15, 1995
Released on J-STAGE: March 28, 2006
JOURNAL FREE ACCESSA neutron generator (HIRRAC) for use in radiobiology study has been constructed at the Research Institute for Radiation Biology and Medicine, Hiroshima University (RIRBM). Monoenergetic neutrons of which energy is less than 1.3 MeV are generated by the 7Li(p, n)7 Be reaction at proton energies up to 3 MeV. The protons are accelerated by a Schenkel-type-accelerator and are bombared onto the 7Li-target. An apparatus for the irradiation of biological material such as mice, cultured cells and so on, was designed and will be manufactured. Neutron and gamma-ray dose rates were measured by paired (TE-TE and C-CO2) ionization chambers. Contamination of the gamma ray was less than about 6% when using 10-μm-thick 7Li as a target. Maximum dose rates for the tissue equivalent materials was 40 cGy/min at a distance of 10 cm from the target. Energy distributions of the obtained neutrons have been measured by a 3He-gas proportional counter. The monoenergetic neutrons within an energy region from 0.1 to 1.3 MeV produced by thin 7Li or 7LiF targets had a small energy spread of about 50 keV (1 σ width of gaussian). The energy spread of neutrons was about 10% or less at an incident proton energy of 2.3 MeV. We found that HIRRAC produces small energy spread neutrons and at sufficient dose rates for use in radiobiology studies.View full abstractDownload PDF (473K) -
BING WANG, XIANG-YAN ZHOU1995 Volume 36 Issue 2 Pages 103-111
Published: June 15, 1995
Released on J-STAGE: March 28, 2006
JOURNAL FREE ACCESSPregnant adult C57BL/6J mice, randomly assigned to 1 of 4 groups, 3 of them were irradiated with β-rays from tritiated water(HTO) by a single intraperitoneal injection on the 12.5th day of gestation. Their offspring received cumulative doses of 0, 5, 10 or 30 cGy in utero. Male pups were trained and examined using a set of behavioral tests that included avoidance acquisition and avoidance maintenance, open field test, hole-board dipping, a water maze, and a food labyrinth. Results were found for most parameters in the 10 and 30 cGy groups that differed significantly from results for the controls, indicating that the behavioral teratogenic effect of prenatal exposure to chronic β-ray radiation from HTO may be greater than the same dose of acute X- or γ-irradiation and that 10 cGy may be the lowest detectable dose level at which behavioral changes is detactable under the conditions used in this experiment.View full abstractDownload PDF (423K) -
HIROSHI ISHIHARA, IZUMI TANAKA, KUMIE NEMOTO, KAZUKO TSUNEOKA, CHEERAR ...1995 Volume 36 Issue 2 Pages 112-124
Published: June 15, 1995
Released on J-STAGE: March 28, 2006
JOURNAL FREE ACCESSIn murine spleen cells, x ray irradiation induces the expression of the IL-1β gene at multiple phases of the peak time. We analyzed the immediate-early phase of IL-1β mRNA accumulation. To determine the lineage of cells that showed the immediate response to irradiation, normal spleen cells were analyzed by Northern blotting and in situ hybridization after separation by magnetic antibodies against specific cell-surface antigens. Although most of the spleen macrophages continuously expressed a low level of IL-1β mRNA, a portion of the macrophage population transiently accumulated large amounts of IL-1β message immediately after irradiation. A macrophage-like leukemia cell line that resembles these inducible macro phages was identified. A similar immediate-early and transient increase in the IL-1β mRNA level occurred when cultured spleen cells were irradiated with a low dose (3 Gy) of x rays. In contrast, the x ray-inducible expression of the IL-1β gene was immediate and continuous, not transient, in spleen cells from whole-body irradiated mice. Results of the run-on transcription assay and the determination of the decrease in the message using cultured spleen and macrophage-like leukemia cells indicated that x ray irradiation appears to activate the transcription of the IL-1β gene and partially stabilize the message. The results show that the x ray-induced immediate-early accumulation of IL-1β mRNA is regulated at both the transcriptional and post-transcriptional levels in an as yet unidentified population of spleen macrophages.View full abstractDownload PDF (619K) -
KUMIE NEMOTO, HIROSHI ISHIHARA, IZUMI TANAKA, GEN SUZUKI, KAZUKO TSUNE ...1995 Volume 36 Issue 2 Pages 125-133
Published: June 15, 1995
Released on J-STAGE: March 28, 2006
JOURNAL FREE ACCESSIL-1β is a stimulator of hematopoietic and inflammatory systems, and also acts as a radioprotector. After whole-body exposure to sublethal doses of ionizing radiation, the IL-1β mRNA level in spleen cells increases for a short time prior to regeneration of the spleen. We analyzed spleen cells of C3H/He mice after whole-body irradiation with 3 Gy x-rays to determine the cause of this short-term increase in the transcription level. An increase in the level of the message in spleen cells, found by Northern blot hybridization, reached its peak 5 to 7 days after irradiation. There was a low correlation between the curves of the mRNA level and the ratio of monocyte/macrophage lineage cells; a typical source of the message. Spleen macrophages that produce a large amount of the message were found 7 days after irradiation in an in situ hybridization experiment in which heterogeneous spleen cell populations were used. In contrast, spleen cells had no detectable levels of macrophages rich in IL-1β mRNA before and 17 days after irradiation. Additionally, the population of message-rich cells was 9.4% of the total number of monocytes/macrophages in the spleen. These results suggest that the short-term increase in IL-β mRNA is a result of the heterogeneous differentiation of a subpopulation of spleen macrophages before regeneration of the spleen.View full abstractDownload PDF (403K) -
TSUNEO MEGUMI, SUMIKO GAMO, TOKUHIRO OHONISHI, YOSHIHARU TANAKA1995 Volume 36 Issue 2 Pages 134-142
Published: June 15, 1995
Released on J-STAGE: March 28, 2006
JOURNAL FREE ACCESSInduction of membrane-associated responses, a leg-shaking, a knock-down and a killing, by γ-ray irradiation was investigated in Shaker (Sh) mutants of Drosophila melanogaster in which the gene cords for the A-current K† channel. Sh mutants were more sensitive in the knock-down response after γ-ray irradiation than wild types. There were a great amount of sex difference in the knock-down response, males being more sensitive than females, but not in the killing response. The sex difference was larger than gene dosage effect on X chromosome in females. Genetical analysis revealed that the sensitivity of the knock-down response is an incompletely dominant character without maternal effects . The leg-shaking response, which had previously been reported to be induced by ether treatment, was demonstrated in the head-removed flies of Sh mutants. It was found to be the most sensitive among the responses tested, and may involve changes in K† channel. The knock-down response may be related to expansion of the leg-shaking response. The killing response should have causes different from the leg-shaking and the knock-down responses judging from the lack of correlation with them.View full abstractDownload PDF (373K) -
TADAAKI BAN-NAI, YASUYUKI MURAMATSU, KEI YANAGISAWA1995 Volume 36 Issue 2 Pages 143-154
Published: June 15, 1995
Released on J-STAGE: March 28, 2006
JOURNAL FREE ACCESSTransfer factors of radionuclides from soil to leaf vegetables (cabbage, Chinese cabbage, komatsuna, spinach and lettuce) have been studied by radiotracer expeiments using Andosol as a representative of Japanese soils. The transfer factors of radioactive Cs, Sr, Mn, Co and Zn for edible parts of vegetables (average of five vegetables) were 0.11, 0.24, 0.61, 0.05 and 0.52, respectively. These values should be used in safety assessment for Japanese agricultural environment. The transfer factors of Mn, Co and Zn for spinach were higher than those for the other vegetables. The transfer factors of Cs for different organs of the leaf vegetables were rather homogeneous. The transfer factors of Sr and Mn were higher for older (outer) leaves than younger (inner) ones. In contrast to Sr and Mn, transfer factors of Zn for younger leaves were higher than those for older ones. The distribution ratios of the elements between soil-solution and soil were in the order Sr>Mn>Cs>Co>Zn, whereas the distribution ratios of the elements between plant and soil-solution were in the order Zn>Cs>Mn>Co>Sr. These results indicate that the selectivity for Sr by plants from the soil-solution was low and that for Zn was very high.View full abstractDownload PDF (404K)
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