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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 2
Displaying 1-6 of 6 articles from this issue
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HIROMITSU WATANABE, TOSHIAKI OGIU, MAYUMI NISHIMURA, YOSHIYUKI MASAOKA ...1998 Volume 39 Issue 2 Pages 93-100
Published: 1998
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSThe effects of heavy ion and X-ray irradiation on tumorigenesis in B6C3F1 mice were compared. Six-week-old animals were divided into 6 groups and exposed to 0.426 Gy heavy ion irradiation of 290 MeV/u carbon-ion beam (LET 60-210 KeV/μm) at the dose rate of 0.4 ± 0.2 Gy/min; 0.5 Gy of X-ray irradiation at 0.1 Gy/min or 5 Gy of X-ray irradiation at 1 Gy/min. The mice were killed and an autopsy performed 13.5 months after the whole body irradiation. Body weights were heaviest for both sexes in the 0.5 Gy group and lightest in the 5 Gy one. Total tumor incidences in the males were 30, 56 and 13% respectively in the heavy ion, 5 Gy and 0.5 Gy X-irradiated groups, stomach tumors, lymphomas and adrenal tumors being the most common outcome of the high dose X-rays. Liver tumor induction did not differ significantly among the groups. In the females tumorigenicity was significantly lower for heavy ion than for 0.5 Gy and 5 Gy X-ray irradiation (P<0.05), the respective incidences, mainly ovary one, being 73%, 17% and 41 %. Non-cancerous lesions, such as graying of the hair, glomerular sclerosis and amyloidosis appeared in the 5 Gy group. These findings indicate that 0.426 Gy of heavy ion irradiation induced lower carcinogenicity than 5 Gy of X-irradiation and higher carcinogenicity than that of 0.5 Gy X-irradiation in male mice.View full abstractDownload PDF (319K) -
TAKEHISA YAMADA, YASUSHI HAYASHI, RYUJI KANEKO, IWAI TOHNAI, MINORU UE ...1998 Volume 39 Issue 2 Pages 101-109
Published: 1998
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSHyperthermia is being investigated as a cancer treatment. Many of its basic mechanisms, particularly those related to cell killing, are still poorly understood. We used a transplanted squamous cell carcinoma cell line to investigate the therapeutic effect of hyperthermia. In particular, we examined the effect of OK-432 (biological response modifier) on hyperthermia-induced apoptosis. In the hyperthermia only group the most extensive necrosis occurred on day 3 (70.3%), and the apoptosis index also was highest on that day (69.3). These results suggest that the induction of apoptosis is closely related to the cell death caused by hyperthermia. The percent of necrosis was significantly higher in the groups given hyperthermia and combined OK-432 and hyperthermia treatment than in the OK-432 group (p<0.05). The apoptosis index was significantly lower in the combined OK-432 and hyperthermia treatment group than in the hyperthermia only group, indicative that the antitumor effect of combined hyperthermia and OK-432 therapy is not ascribable to the induction of apoptosis.View full abstractDownload PDF (703K) -
KUMIO OKAICHI, LI-HONG WANG, MAKOTO IHARA, YUTAKA OKUMURA1998 Volume 39 Issue 2 Pages 111-118
Published: 1998
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSWe have constructed an in vitro system to examine how p53 mutants affect radiosensitivity. Mutations of p53 were made using in vitro mutagenesis, and mutant cDNAs were introduced into the human osteosarcoma cell line, Saos-2, which is devoid of endogenous p53. For wild type p53, both the expression plasmid and a regulation plasmid (LacSwitch system) were transfected into the cells. The radiosensitivities of clones of mutant p53 and wild type p53 were examined. Transformants of wild type p53 had increased radiosensitivity. The induction of wild type p53 protein by addition of IPTG did not significantly increase radiosensitivity. A mutation at codon 123 also increased radiosensitivity. Mutations at codons 143, 175, and 273 did not alter radiosensitivity.View full abstractDownload PDF (357K) -
YASUHITO ISHIGAKI, KAZUHIRO YASUDA, NORIYOSHI HASHIMOTO, JUN-ICHIRO HA ...1998 Volume 39 Issue 2 Pages 119-127
Published: 1998
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSTo gain an insight into the relationship between UVB-carcinogenesis and natural killer activity, we examined ultraviolet light-induced carcinogenesis in mice with high natural killer activity (KSN) and mice with natural killer deficiency (KSN-bg). We exposed mice six times a week to three levels of daily ultraviolet B (UVB) doses; 320, 160 and 0 J/m2/day. During the latency period of skin tumor development in KSN mice, we detected no suppression of the natural killer activity at both 320 and 160 J/m2/day. Even at 1340 J/m2/day, we could not detect any significant suppression of NK activity in KSN mice. When we irradiated spleen cells in vitro, we observed NK activity suppression. Next, we compared the carcinogenic effects of UVB-irradiation on KSN and KSN-bg mice. At 320 J/m2/day, we detected no significant differences between them. In contrast, at 160 J/m2/day, KSN-bg mice showed a significantly higher rate of skin tumor induction than KSN mice (p < 0.05). Most UVB-induced tumors were squamous cell carcinoma, the rest were spindle cell carcinoma, papilloma and mixed type. Our results suggest that NK activity plays a protective role against UVB-carcinogenesis from low daily-doses of UVB-irradiation.View full abstractDownload PDF (377K) -
SHUN''ICHI HISAMATSU, TEI''ICHI KATSUMATA, YUKIO TAKIZAWA1998 Volume 39 Issue 2 Pages 129-136
Published: 1998
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSSamples of pine needle, litter and soil samples collected in/around Akita City and Rokkasho Village in 1989 were analyzed for both free water 3H (FWT) and organically-bound 3H (OBT). The FWT concentrations decrease in the order, litter or soil > pine needle. FWT concentrations in soil depend on the moisture content, and tend to increase with decreasing soil moisture content. This relationship is consistent with the observation that FWT in the soil increases with oxidation of atmospheric tritiated hydrogen gas (HT) and decreases with rainwater dilution. The OBT concentrations increase in the order pine needle < litter < soil at most of the sampling locations. This suggests that historically high soil 3H concentrations may be reflected as high OBT concentrations in soils of the present.View full abstractDownload PDF (303K) -
TADASHI TAKEMOTO, QIU-MEI ZHANG, YUKIKO MATSUMOTO, SEIJI MITO, TADAHID ...1998 Volume 39 Issue 2 Pages 137-144
Published: 1998
Released on J-STAGE: March 27, 2006
JOURNAL FREE ACCESSIonizing radiation and hydrogen peroxide (H2O2) produce many types of oxidative DNA damage such as strand breaks, apurinic/apyrimidinic (AP) sites, base modifications and 3''-blocking damage such as 3''-phosphoglycolated and 3''-phosphorylated termini. AP sites and 3''-blocking damage are repairable by exonuclease III and endonuclease IV in Escherichia coli. XthA-nfo double mutants of E. coli, which are deficient in exonuclease III and endonuclease IV, were highly sensitive to lethal and mutagenic effects of H2O2, compared with the wild-type strains. The pNT180 and pNT186 plasmids containing wild-type nfo and mutant nfo-186 gene, respectively, were introduced into the xthA-nfo mutant. The nfo-186 gene product, Nfo186, retained normal AP endonuclease activity but could not remove 3''-blocking damage from DNA. The pNT180 corrected the sensitivity of the xthA-nfo mutant to lethal and mutagenic effects of H2O2. On the other hand, the pNT186 did not have any complementation effects. From these results it was concluded that 3''-blocking damage rather than an AP site is the primary lesion responsible for both lethal and mutagenic effects of H2O2.View full abstractDownload PDF (320K)
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