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Volume 11, Issue 2
Displaying 1-7 of 7 articles from this issue
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L. A. Chuang, C. Y. Wong, S. Y. Lau1970 Volume 11 Issue 2 Pages 53-60
Published: August 01, 1970
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSMeasurements of the absorbed dose rate from soil samples and above the ground at the site, from which the soil samples were taken, were carried out in Hong Kong by means of spectrometric method using a plastic scintillator. Under the present experimental setup used, a correlation factor of 14.9 between the absorbed dose rate at one meter above the ground in site measurement and that of the corresponding soil sample was obtained. The overall average values of 70.5 mrad/y and 15.9 mrad/y were obtained for the absorbed dose rate due to natural radioactivity and fall-out radioactivity, respectively. The absorbed dose rates due to the fall-out differed by a factor of approximately three, between the two geographically separated areas ; StanleySau Ki Wan and Kowloon-N. T.View full abstractDownload PDF (332K) -
Muneyasu URANO, Ichiro SHIRAKURA, Norimoto TANAKA1970 Volume 11 Issue 2 Pages 61-69
Published: August 01, 1970
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSSome basic experiments were performed on our animal-tumor system of Ehrlich ascites carcinoma cells in ddYF mice. All the results are presented in terms of TD50 or the number of cells which transplant tumor in half of the recipients. The animals responded to active immunization and to whole body irradiation with 400 rads with an increase and a decrease of TD50 respectively. It is of interest that TD50 correlated negatively with the number of lethally irradiated tumor cells (LR cells) when viable cells were transplanted together with LR cells. The TD50 fell as the number of LR cells increased and it finally seems to approach to one viable cell. A method of drawing x-ray survival curves of tumor cells without using LR cells is discussed, and an example is given which indicate that our Ehrlich ascites tumor cells irradiated under hypoxic conditions “in vitro” or “in situ”** have a radiosensitivity of m = 2 and D0 = 390 rads.View full abstractDownload PDF (409K) -
Shigetoshi ANTOKU, Shozo SAWADA1970 Volume 11 Issue 2 Pages 70-78
Published: August 01, 1970
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSThe protective effects of AET against acute death, intestinal disorders and hematopoietic injuries in mice irradiated with 14 Mev neutrons were compared with those against X-ray damages.
AET was effective for acute death and hematopoietic injuries in mice exposed to fast neutrons. The protective activity for fast neutrons was, however, significantly less than that obtained with X-rays.
For intestinal injuries caused by fast neutrons, MEG had no protective activity, whereas it was significantly protective against X-rays.View full abstractDownload PDF (353K) -
Kimiko ARAKI, Shigetoshi TAGUCHI, Harumi OHYAMA, Takeshi YAMADA1970 Volume 11 Issue 2 Pages 79-84
Published: August 01, 1970
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSIncorporation of 14C-pyruvate into the citric acid cycle metabolites was measured in rat thymocytes X-irradiated in vitro. X-irradiation caused no significant changes in 14C-pyruvate incorporation into the metabolites separated by Dowex-1 formate column chromatography. Glycogen content of the cells decreased, whereas malate showed a significant accumulation after irradiation. From the results, the previously reported increase in labeling of citric acid cycle metabolites derived from 14C-glucose was explained as the result of the enhanced glycolysis in the thymocytes after irradiation.View full abstractDownload PDF (212K) -
Kazuhiko YAMAMOTO1970 Volume 11 Issue 2 Pages 85-91
Published: August 01, 1970
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSLysozyme in 0.5% aqueous solution has been irradiated with several doses of Co60-γ-rays. The effects of γ-radiation on lysozyme molecule have been studied by the methods of amino acid analysis, N-terminal amino acid analysis, measurement of amide-nitrogen content, ultraviolet spectroscopy, and ultracentrifugal analysis. In sample losing 69% of its initial enzyme activity on irradiation of 1.4 × 106 R., no significant change is observed in amino adid composition and amide-nitrogen content. And any other N-terminal amino acids than lysine which is expected to be released by peptide bond cleavage, are not detected. But, ultracentrifugal analysis of the irradiated lysozyme indicates the existence of polymerized component in addition to the intact lysozyme. Mechanisms of γ-ray inactivation on lysozyme and roles of the polymerized component have been discussed.View full abstractDownload PDF (360K) -
Yoiti TITANI, Yutaka KATSUBE1970 Volume 11 Issue 2 Pages 92-97
Published: August 01, 1970
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSThe radioprotective action of Tween 80 against strand breaks in the DNA of E. coli irradiated in situ with 60Co γ-rays was investigated using an alkaline sucrose sedimentation technique. Tween 80 (0.1 M) caused the number of breaks to be decreased by a factor of 1.3, a value very close to DRF for E. coli BS-1 obtained from the survival studies. On the other hand, this DRF value was considerably lower than that expected from the DRF for E. coli B/r obtained from survival studies. When M3H-TdR labelled E. coli B/r was irradiated with 15 kR, 3H-release during post-irradiation incubation was 20%; while the presence of 0.1 M Tween 80 during the irradiation decreased the 3H-release to 15%, even after as much as 30 kR irradiation. These facts suggest that the action of Tween 80 is not only to diminish the number of breaks of DNA but to cause some change in structural nature of the breaks so that they can be repaired in a short time without any excision of DNA fragments.View full abstractDownload PDF (266K) -
Yoshikazu INOUE, Masanobu SAKANOUE1970 Volume 11 Issue 2 Pages 98-106
Published: August 01, 1970
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSThe contents of plutonium-239 in soil were determined by using 238Pu as yield tracer. The samples were decomposed by nitric acid treatment under ultrasonic vibration and the separation of plutonium from other elements was carried out by using anion exchange resin. The surface soils showed the plutonium content of about 1 ?? 4 mCi/km2 and their 239Pu/90Sr activity ratios were 2 ?? 5%. From these results, it was concluded that 239Pu in soil at present was brought mainly by the fall-out due to the nuclear bomb test explosion.View full abstractDownload PDF (318K)
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