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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 3
Displaying 1-6 of 6 articles from this issue
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KEI YANAGISAWA, YASUYUKI MURAMATSU1995 Volume 36 Issue 3 Pages 171-178
Published: September 15, 1995
Released on J-STAGE: March 28, 2006
JOURNAL FREE ACCESSSoil-plant transfer factors (concentraion ratio between the plant and soil) of technetium in paddy and upland rice plants were obtained from laboratory experiments. The transfer factor is one of the most important parameters for environmental radiation dose assessment. Technetim tracer (95mTcO4-) was added to the soil prior to rice cultivation. The transfer factor of technetium for the hulled grains (brown rice) of paddy rice (≤0.0002) was much lower than for that of upland rice (0.021). The transfer factors for both types of hulled grains were much lower than in the leaves. The technetium decontamination rate from hulled grains by polishing was 34%, the percentage of the weight decrease being 12%. The concentration of technetium in the soil solution collected from the paddy rice soil (flooded conditions) decreased rapidly with time due to its adsorption on the soil. In the upland rice soil (non-flooded) solution, the decrease in the technetium concentration was fairly slow. The low transfer factors for the paddy rice plants could be explained by the immobilization of technetium in the flooded soil. The oxidation-reduction potentials (Eh) in the flooded soil decreased rapidly with time. We conclude that technetium tracer added as TcO4- to flooded soil is readily transformed to an insoluble form (e.g.TcO2) under the reducing conditions provided by flooding.View full abstractDownload PDF (326K) -
TAKERU MINAMISAWA, KOUICHI HIROKAGA1995 Volume 36 Issue 3 Pages 179-184
Published: September 15, 1995
Released on J-STAGE: March 28, 2006
JOURNAL FREE ACCESSThe spontaneous circadian motor activity of first generation (F1) hybrid male C57BL/6×C3H mice irradiated with gamma rays on the 14th day of gestation was studied at the following ages : young (6-7 months), adult (12-13 months), and old (19-20 months). Doses were 0.1, 0.2, 0.5 or 1.0 Gy. A 12-hour day-night cycle was maintained with light on at 6:00 hr. Spontaneous circadian motor activity was recorded with a capacitance-induction motility monitor for 48 consecutive hours. Activity was measured at 2-hour intervals, and the data stored on computer discs. The activity of the 1.0 Gy group recorded at 22:00 and 2:00 hr for young mice and at 2:00 hr for adult ones was significantly higher than that of the age-matched control group. Results suggest that male mice irradiated with 1.0 Gy at gestational day 14 show nocturnal hyperactivity in the young and adult stages.View full abstractDownload PDF (277K) -
YASUHIRO KAGAWA, FUMIO YATAGAI, MASAO SUZUKI, YOUKO KASE, AKIKO KOBAYA ...1995 Volume 36 Issue 3 Pages 185-195
Published: September 15, 1995
Released on J-STAGE: March 28, 2006
JOURNAL FREE ACCESSMultiplex PCR analysis of HPRT(-) mutations in human embryo (HE) cells induced by 230 keV/μm carbon-ion irradiation showed no large deletion around the exon regions of the locus gene in contrast to the irradiations at different LETs. To identify these mutations, the sequence alterations in a cDNA of hprt gene were determined for 18 mutant clones in this study. Missing of exon 6 was the most frequent mutational event (10 clones), and missing of both exons 6 and 8 was next most frequent event (6 clones), then base substitutions (2 clones). These characteristics were not seen in a similar analysis of spontaneous mutations, which showed base substitution (5 clones), frameshift (2 clones), missing of both exons 2 and 3 (2 clones), and a single unidentified clone. Direct sequencing and restriction enzyme digestion of the genomic DNA of the mutants which showed missing of exons 6 and 8 in the cDNA, supports the possibility that they were induced by aberrant mRNA splicing.View full abstractDownload PDF (443K) -
NAONORI MATSUSAKA, HIDEKI SAKAMOTO, ITARU SATO, KUNIHIRO SHINAGAWA, HA ...1995 Volume 36 Issue 3 Pages 196-202
Published: September 15, 1995
Released on J-STAGE: March 28, 2006
JOURNAL FREE ACCESSWhole-body retention and fetal uptake of 65Zn under a Zn-deficient diet were studied in pregnant mice in the late gestational stage after a single oral administration of 65Zn. 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 65Zn transmitted to the offspring in utero was greater in the Zn-deficient diet group. In another experiment, fetal uptake of 65Zn in dams on gestation day 17 was examined over a period of 24 hr after a single intravenous administration of 65Zn 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 65Zn retained in the maternal body was transmitted to the in utero offspring in both groups.View full abstractDownload PDF (292K) -
Lithium Delays the Radiation-induced Apoptotic Process in External Granule Cells of Mouse CerebellumMINORU INOUYE, HIDEKI YAMAMURA, ATSUHIRO NAKANO1995 Volume 36 Issue 3 Pages 203-208
Published: September 15, 1995
Released on J-STAGE: March 28, 2006
JOURNAL FREE ACCESSProliferating cells of the external granular layer (EGL) in the developing cerebellum are highly sensitive to ionizing radiation. We examined the effect of lithium, an inhibitor of intracellular signaling, on the manifestation of radiation-induced apoptosis. Newborn mice were exposed to 0.5 Gy gamma-irradiation alone, or first were treated with lithium (10 μmol/g, SC) then given 0.5 Gy irradiation 2 hr later. The EGL was examined histologically for apoptosis at various times after treatment. Apoptotic cells increased rapidly, peaked (about 14%) 6 hr after irradiation, then decreased gradually to the control level by 24 hr. Prior treatment with lithium delayed the manifestation of apoptosis, the peak appearing at 12 hr. The disappear ance of dead cells was delayed for about one day. The lithium concentration in the whole brain increased rapidly, being 30 μg/g at the time of irradiation and remaining at more than 40 μg/g for 40 hr. Lithium is reported to inhibit guanine-nucleotide binding to G proteins as well as phosphoinositide turnover. Of the variety of lesions induced by radiation, DNA double strand breaks are the most important source of cell lethality. The present findings, however, suggest that cyclic AMP-mediated and/or phosphoinositide-mediated signaling systems regulate radiation-induced apoptosis.View full abstractDownload PDF (337K) -
YUKO IBUKI, RENSUKE GOTO1995 Volume 36 Issue 3 Pages 209-220
Published: September 15, 1995
Released on J-STAGE: March 28, 2006
JOURNAL FREE ACCESSThe activation of macrophages (Mφ) by low-dose irradiation (4cGy) was examined. The irradiated Mφ were obtained from mice exposed to a low dose of γ-rays. The addition of excess irradiated Mφ suppressed more the concanavalin A-induced proliferation of splenocytes than that of unirradiated Mφ. This was attributed to large nitric oxide (NO) production from irradiated Mφ. In addition, low-dose irradiation augmented NO production and glucose consumption in Mφ treated with interferon-γ alone or interferon-γ/ lipopolysaccharide. Furthermore, low-dose-irradiated Mφ showed a higher cytolytic activity against P-815 mastocytoma cells than unirradiated Mφ, indicating that the NO production was involved in the activity. On the other hand, the Mφ irradiated with a low dose in vitro did not enhance the NO production. These findings suggest that whole-body irradiation with a low dose of γ-rays activates Mφ indirectly and consequently enhances NO production from Mφ, by which the self-defense systems such as the tumoricidal activity will be augmented.View full abstractDownload PDF (560K)
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