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Volume 11, Issue 3-4
Displaying 1-10 of 10 articles from this issue
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Kouji MASUDA1970 Volume 11 Issue 3-4 Pages 107-112
Published: September 01, 1970
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSIn order to clarify whether the effects of neutrons on mammalian cells are qualitatively different from those of X or gamma-rays, L cells were irradiated with D-T neutrons and 180 kvp X-rays, singly or combined. From analysis of dose response curves, it is concluded that cell killing mechanism of neutrons is not the same as that of X-ray, but there is something common in part between them. RBE values of neutrons with respect to X-rays calculated from dose response curves was 2.5-1.5 for 50%-1% survival.View full abstractDownload PDF (263K) -
Kozo OHTSUKI, Masakatsu FUKUHARA, Koichiro SUMIZU, Hiroyuki HATANO1970 Volume 11 Issue 3-4 Pages 113-119
Published: September 01, 1970
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSWhen subtilisin BPN' solutions were irradiated with 60Co γ-rays, three hydrolytic activities of the subtilisin toward N-acetyl-L-tyrosine ethyl ester (ATEE), N-benzoyl-L-arginine ethyl ester (BAEE), and casein were found to be lost at different rates with doses of 30 to 300 k rads. The esterase activity toward ATEE was most radio-sensitive and the protease activity toward casein was most radio-resistant. Behaviors of the irradiated subtilisins on electrophoresis showed that these enzymes had more electronegative charges than native ones. Two tyrosine, one tryptophan, one methionine, and one histidine residues were lost from the irradiated subtilisin which had 55% survival activity of the hydrolysis of ATEE after exposure to 110k rads of γ-rays, but still had 70% BAEE, 75% casein hydrolytic activities and 85% active site which was determined by using diisopropyl fluorophosphate. These results suggest that the radiolysis of these several amino acid residues in subtilisin carries about these new features of irradiated subtilisin against the three kinds of substrates.View full abstractDownload PDF (339K) -
Kozo OHTSUKI1970 Volume 11 Issue 3-4 Pages 120-126
Published: September 01, 1970
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSEffects of 60Co γ-ray irradiation on subtilisin BPN' solutions have been studied. Kinetic parameters of the enzyme toward N-acetyl-L-tyrosine ethyl ester and N-benzoyl-L-arginine ethyl ester were affected in a different way by the irradiation. Amino acid composition of γ-irradiated diisopropyl phosphoryl-subtilisin, which was separated from low molecular weight fractions by gel-filtration, showed that two tyrosine and about one tryptophan residues were damaged and one methionine residue was oxidized to methionine sulfoxide with dosage of 125 k rads. Conformational changes of the irradiated enzyme were studied by two methods. Modification with 5-diazo-l-H-tetrazole and hydrolysis with achymotrypsin of the irradiated diisopropyl phosphoryl-subtilisin indicated that the tertiary structure of the enzyme was less rigid than the native one. From these results, it is concluded that the radiation damage of a few amino acid residues in the enzyme brought about the conformational changes and the altered kinetic parameters of the irradiated enzyme.View full abstractDownload PDF (287K) -
Takeru MINAMISAWA, Hiroshi SUGIYAMA, Takehiko TSUCHIYA, Hideo ETO1970 Volume 11 Issue 3-4 Pages 127-133
Published: September 01, 1970
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSEffects of X-rays on visual system were electrophysiologically studied in rabbits which were subjected to 250 R orf 500 R or head-only irradiation. Three types of the evoked potentials which were elicited in the visual cortex and in the lateral geniculate body by photic stimulation and in the visual cortex by electrical stimulation to the lateral geniculate body were recorded up to 10 days following irradiation. The amplitude and the duration of the evoked potential from the visual cortex by photic stimulation decreased and reached a minimum value 8 hours after irradiation. This was immediately followed by a gradual increase in amplitude and duration to levels close to the control on the first day, but the return to control was not complete, even at the end of 10 days. These reductions were more marked after irradiation of 500 R than that of 250 R. The changes of the two other potentials were very similar to that elicited in the visual cortex by photic stimulation. These results can be attributed to a depressing influence of X-rays on the whole visual system. This finding draws further attention to the fact that these potentials depend on events occurring in the reticular formation. Some implications of the effects of X-rays on the rabbit visual system are discussed.View full abstractDownload PDF (304K) -
William L. LAPPENBUSCH1970 Volume 11 Issue 3-4 Pages 134-137
Published: September 01, 1970
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSThe radiosensitivity of the salamander irradiated with 1, 000 R and stored at 15°C, was found to fluctuate drastically over a 24 hour period, the greatest change in survival times occurring between 2, 100 (9: OOPM) and 2, 400 (midnight). Radiosensitivity appears to be related to the lightdark cycle and to the circadian rhythm previously noted in these and other animals. This study clearly emphasizes the importance of reporting the exact time of day in which radiation exposures are administered to Taricha granulosa and perhaps other animals.View full abstractDownload PDF (153K) -
Susumu MINATO, Minoru KAWANO1970 Volume 11 Issue 3-4 Pages 138-144
Published: September 01, 1970
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSFormulae concerning the intensity of ionization due to the terrestrial gamma-radiations which include both the primary gamma-radiation from radioactive nuclides in the ground and the radiation scattered in soil and air were obtained by using build-up data with respect to aluminum and water for a point source. The intensities of ionization due to terrestrial gamma-radiation above and below the ground surface were calculated by the formulae with the aid of the “true” photon spectrum of the radiation in the air on the campus of Nagoya University, and the relation between the ionization intensity and altitude or depth was obtained.View full abstractDownload PDF (240K) -
Fumiaki SATO, Wataru NAKAMURA, Hideo ETO1970 Volume 11 Issue 3-4 Pages 145-150
Published: September 01, 1970
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSAssuming a linearity of Gompertz function, the effects of radiation on the two parameters of Gompertz function were estimated for single or continuous exposure. The dependence of the two parameters on dose or dose-rate were given in analytic forms. In the range of dose usually used in mice experiments, the percents of life-shortening yield approximately the same values, irrespective of measures such as mean, median, or mode of survival time. The mathematical model describes the data on life-shortening, Gompertz function and daily death distribution with consistency.View full abstractDownload PDF (182K) -
Takeru MINAMISAWA, Hiroshi SUGIYAMA, Takehiko TSUCHIYA, Hideo ETO1970 Volume 11 Issue 3-4 Pages 151-156
Published: September 01, 1970
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSThe visual evoked potential of adult rabbits, who had been irradiated with 75 R of X-rays on the 11th day of gestation, was studied. The effect of Nembutal on the evoked potentials was also investigated. Three types of evoked potentials, which were elicited in the visual cortex and in the lateral geniculate body by photic stimulation and in the visual cortex by electrical stimulation to the lateral geniculate body, were recorded before and 2, 3, 4 and 5 hours after injection of Nembutal. No significant difference in the visual evoked potential was observed between the irradiated and the non-irradiated animals, but the effect of Nembutal on this potential was slightly smaller for the irradiated animals. These results suggest that the activity of the reticular formation in the irradiated animals may have been affected by the radiation.View full abstractDownload PDF (242K) -
Osamu MATSUOKA, Emiko MURAMATSU, Masatoshi KASHIMA1970 Volume 11 Issue 3-4 Pages 157-165
Published: September 01, 1970
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSEffects of internal irradiation by 90Sr and 131I were compared using 14C-glucose oxidation test in mice. Mice were injected with 2 μCi/g body weight of 90Sr or 5 μCi/capita of 131I for internal irradiation. At one day or 1, 3, 6, 9 weeks after injection of 90Sr and one or seven days after injection of 131I, the respiratory 14CO2 patterns of the animals were studied by continuous measurement of 14CO, and CO, in the exhaled air. The time course pattern of specific activity was obtained by calculating the ratios of the observed value of 14CO2 and CO2. The effect of internal exposure on respiratory 14CO2 were evaluated by the following parameters ; 1) peak time, i. e., the time from injection to maximum specific activity, and 2) peak height, the maximum specific activity at peak time.
In the control group, the value of specific activity of exhaled 14CO2 increased immediately after 14C-glucose administration, reached the maximum at 30 minutes and then gradually decreased. Internal irradiation with 90Sr caused a front shift, i. e., decrease in peak time with no appreciable change in peak height as compared with control. In the case of 131I, the respiratory pattern underwent an upper shift, i, e., increase in peak height with no change in peak time.
To clarify the mechanism of the phenomena obtained by these internal emitters, the effect of some drugs on the change of respiratory 14CO2 pattern were studied. It was suggested that respiratory 14CO2 pattern analysis may serve as a useful tool in the comparative study of the effect of various internal emitters.View full abstractDownload PDF (387K) -
Chemical Radiation Protection in Man as Revealed by Chromosome Aberrations in Peripheral LymphocytesYoshimasa TANAKA, Tsutomu SUGAHARA1970 Volume 11 Issue 3-4 Pages 166-168
Published: September 01, 1970
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSPatients with cervical carcinoma under radiotherapy have been followed during and after radiotherapy for the incidence of chromosome aberrations in peripheral lymphocytes. In patients treated with adrenochrome monoguanylhydrazone methansulfonate (100 mg) before every irradiation the incidence was significantly lower than in those without the treatment. The result indicates chemical protection in man for the first time.View full abstractDownload PDF (141K)
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