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Volume 39 (1998)
- Issue 4 Pages 239-
- Issue 3 Pages 165-
- Issue 2 Pages 93-
- Issue 1 Pages 1-
Volume 39, Issue 3
Displaying 1-7 of 7 articles from this issue
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HIROSHI UTSUMI, SEIJI KODAMA, KEIZO TANO, MITSUMASA W. HASHIMOTO, HIRO ...1998 Volume 39 Issue 3 Pages 165-174
Published: 1998
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSContact-inhibited catalase-deficient fibroblast cell strain has been established from the homozygous hypocatalasemic C3H/Csb mutant mouse. This cell strain has low level of catalase enzyme activity and has normal level of enzyme activities of both glutathione peroxidase and superoxide dismutase. Catalase-deficient C3H/Csb mutant cell strain is markedly more sensitive to the toxicity of hydrogen peroxide compared to wild-type C3H/Csa cell strain. In addition, mutant cell strain is sensitive to X-rays and near-UV compared to wild-type cell strain, but shows the same sensitivities to topoisomerase II inhibitors, adriamycin and 4''-(9-acridinylamino) methanesulfon-m-anisidide (m-AMSA), and the DNA cross-linking agents, cis-diamminedichloroplatinum (II) (cis-Pt) and trans-diamminedichloroplatinum (II) (trans-Pt). These cell strains will be of use in the study of the roles which catalase plays in the intracellular prevention of DNA damage induced by oxidative stress.View full abstractDownload PDF (391K) -
HYUN-JUNG SONG, TAI-HWAN KIM, CHUL-KOO CHO, SEONG-YUL YOO, KYUNG-SOOK ...1998 Volume 39 Issue 3 Pages 175-184
Published: 1998
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSThe correlation between ornithine decarboxylase (ODC) protein induction and specific protein kinase C (PKC) isozyme expression by gamma-ray in 12-O-tetradecanoylphorbol-13-acetate(TPA)-treated normal and v-rasHa transformed mouse keratinocytes was examined. TPA at 100 nM was treated in primary mouse keratinocytes immediately after 4 Gy, 8 Gy and 16 Gy gamma-ray irradiation. After 4 hrs, cells were harvested and the protein expression levels of PKC isozymes (PKCα, -δ, -ε, -η and -ζ) and ODC were examined. For v-rasHa infection, primary keratinocytes were infected with a defected retrovirus containing the v-rasHa gene. After 3 hrs of irradiation, each PKC isozyme and ODC protein expression were tested. Gamma-ray increases ODC protein expression in both TPA-treated normal and v-rasHa transformed mouse keratinocytes and this phenomenon correlated to the increased induction of PKCα without altering other PKC isozymes. Tyrosine phosphorylation of epidermal growth factor receptor protein was also stimulated during gamma-ray induced cellular changes in TPA-treated normal mouse keratinocytes. These results indicate that PKCα as an important regulator of mouse epidermal changes by gamma-radiation, contributes to the ODC expression occurring during exposure to tumor promoter, such as TPA, and epidermal neoplasia induced by ras activation.View full abstractDownload PDF (574K) -
NORI NAKAMURA, JANINE F. KATANIC, CHYUZO MIYAZAWA1998 Volume 39 Issue 3 Pages 185-191
Published: 1998
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSElectron spin resonance (ESR) measurement data of 98 teeth from atomic-bomb survivors who received various radiation doses were analyzed in terms of possible solar light exposure by tooth position. Each tooth was divided into buccal and lingual parts for independent ESR measurement. We found that average buccal doses were larger than their corresponding lingual doses by 0.48±0.30 Gy (first incisors), 0.33±0.38 Gy (second incisors), 0.20±0.23 Gy (canines), 0.24±0.26 Gy (first bicuspids), 0.17±0.51 Gy (second bicuspids) and 0.04±0.18 Gy (large molars and wisdom teeth). Such a clear declining trend following tooth position in the mouth is readily appreciated as due to solar light exposures. Comparisons of lingual doses of multiple teeth from the same five donors suggest that lingual doses of first incisors were also overestimated by 0.34±0.18 Gy. From the results presented, we deduce that the buccal doses of first incisors are, on the average, overestimated by nearly 0.8 Gy. Therefore, use of front teeth for biodosimetry requires special caution. How to estimate the contribution from exposure to solar light in ESR biodosimetry is discussed.View full abstractDownload PDF (302K) -
ZHEN-BO HAN, HIROMI SUZUKI, FUMIO SUZUKI, MASAO SUZUKI, YOSHIYA FURUSA ...1998 Volume 39 Issue 3 Pages 193-201
Published: 1998
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSSyrian hamster embryo cells were used to study the morphological transformation induced by accelerated heavy ions with different linear energy transfer (LET) ranging from 13 to 400 keV/μm. Exponentially growing cells were irradiated with 12C or 28Si ion beams generated by the Heavy Ion Medical Accelerator in Chiba (HIMAC), then inoculated to culture dishes. Morphologically altered colonies were scored as transformants. Over the LET range examined, the frequency of transformation induced by the heavy ions increased sharply at very low doses no greater than 5 cGy. The relative biological effectiveness (RBE) of the heavy ions relative to X-rays first increased with LET, reached a maximum value of about 7 at 100 keV/μm, then decreased with the further increase of LET. Our findings confirmed that high LET heavy ions are much more effective than X-rays for the induction of in vitro cell transformation.View full abstractDownload PDF (364K) -
MASAO SUZUKI, ZHI YANG, KAZUSHIRO NAKANO, FUMIO YATAGAI, KEIJI SUZUKI, ...1998 Volume 39 Issue 3 Pages 203-213
Published: 1998
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSWe studied the effect of repeated irradiation with a low dose rate (about 0.0012 cGy per min) of 60Co γ-rays on the in vitro life-span of human embryo (HE) cells. HE cells were cultured in an incubator that was set in a 60Co γ-ray-irradiation room, and the irradiation was repeated throughout the life-span of the HE cells (for about 150 to 160 days) on every day base. During this period, the cells accumulated 106 to 123 cGy. The life-span of the irradiated cells prolonged 1.14 to 1.35 times when compared to that of non-irradiated cells. The incidence of cells with chromosome bridge and micronuclei significantly increased in the irradiated cells. Although the number of chromosomes gradually changed with repetition of culture in both non-irradiated and irradiated cells, the frequencies of aneuploid cells in irradiated cells were about two times higher than that in non-irradiated cells. These results indicate that repeated irradiation with a low dose of γ-rays produces chromosome instability, and it may be a cause of numerical chromosome abnormalities and life-span extension of irradiated cells.View full abstractDownload PDF (488K) -
SHOZO SUZUKI1998 Volume 39 Issue 3 Pages 215-221
Published: 1998
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSSeveral models for the action of mixed irradiation with two types of radiation have been proposed in the last two decades, although the superiority or inferiority of these models is not completely elucidated. However, mixed irradiation is sometimes composed of more than two types of radiation, and for this type of mixed irradiation, no model has yet been proposed. Therefore, I have tried to make a model for this type of mixed irradiation. This paper presents a survival model for simultaneous mixed irradiation with multiple (n) types of radiation, and this model would be helpful for assessing the effects of simultaneous mixed irradiation with multiple types of radiation in nature, accidents, etc.View full abstractDownload PDF (219K) -
SATORU ENDO, YUMIKO NITTA, MEGU OHTAKI, JUN TAKADA, VARELI STEPANENKO, ...1998 Volume 39 Issue 3 Pages 223-230
Published: 1998
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSThe dose absorbed fraction of rat thyroid by internal deposit of 131I has been calculated as a function of effective diameter of thyroid. The calculations were done using two types of Monte Carlo simulations: one was by a simple energy-loss calculation in spherical volume according to the electron stopping power, and another by a more realistic simulation using Monte Carlo N-Particle Transport code system Version 4A (MCNP). These two calculations were consistent with each other within a deviation of 5%. The absorbed fractions in spherical thyroid were drastically changed up to 5 mm diameter, and then almost all energy was deposited within 10 mm diameter.
For the practical application to the animal experiment, the absorbed fractions of ellipsoid-shaped thyroids were also calculated for 1-, 4- and 9-week-old rats, where the fractions were estimated to be 0.61, 0.67 and 0.68, respectively. It was also found that the absorbed fraction of the ellipsoid with various dimensions can be simulated by a calculation for spherical volume with a comparable effective diameter.View full abstractDownload PDF (280K)
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