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Volume 15 (1974)
- Issue 4 Pages 171-
- Issue 3 Pages 121-
- Issue 2 Pages 75-
- Issue 1 Pages 1-
Volume 15, Issue 3
Displaying 1-9 of 9 articles from this issue
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S. MURAMATSU1974 Volume 15 Issue 3 Pages 121-126
Published: September 01, 1974
Released on J-STAGE: July 14, 2006
JOURNAL FREE ACCESSLong-term effects of continuous gamma-irradiation with a dose-rate of 6 R/day were studied of mouse ovaries which had been irradiated during whole reproductive period, namely from conception until adult age. In the non-irradiated control group age-related changes were observed in their ovaries from 35 to 400 days of age. In the irradiated group, severe histopathological damages were detected in the ovaries. At 35 to 65 days of age, only a few abnormal oocytes were counted in their ovaries. All the females had permanent sterility (the accumulated dose of 330R), and ovarian tumours appearred at early ages (120 days old) as compared to controls (400 days old). The irradiation experiments for a limited period of mice's life-span showed that the irradiation during the suckling period (from birth to weaning) induced a permanent sterility, while the irradiation during the foetal period or the weaning-juvenile period resulted in a partial deletion of oocytes and a partial decrease of ovary weight.View full abstractDownload PDF (322K) -
H. OHARA, T. INADA1974 Volume 15 Issue 3 Pages 127-131
Published: September 01, 1974
Released on J-STAGE: July 14, 2006
JOURNAL FREE ACCESSThe HeLa S3 cells were placed in the hypoxic condition by repeating the evacuation-and-N2-flushing step in a small irradiation box. The oxygen concentration in the culture medium was, then, estimated at every step of the gas exchange process and was reduced to as low as 7.0μ moles litre-1 (about 5, 300 volume or 0.225 weight ppm) within 30 minutes. The dose survival curves under various hypoxic conditions showed that, with increasing the degree of hypoxia, the Do was increased and the extrapolation number (n) was reduced.View full abstractDownload PDF (284K) -
A. OKUDA1974 Volume 15 Issue 3 Pages 132-139
Published: September 01, 1974
Released on J-STAGE: July 14, 2006
JOURNAL FREE ACCESSMild heating (52°C for 20 min) of stationary phase cells of E. coli B/r starved for 2 hr caused little killing effect (80% survival) but induced division delay (2.5 hr). When heat and UV (750 erg mm-2)-treated cells were incubated in growth medium, extensive lag phase (6 hr) in cultural respose and prolonged period (4 hr) susceptible to constant level of photoreactivation were observed. Liquid holding recovery was inhibited by pre-UV heat treatment. Pyrimidine dimers in heat and UV-treated cells were not excised during 4 hr of post-incubation in growth medium. After prolonged incubation, dimer excision resumed, although the rate was much slower than in the cells treated with UV alone. It is concluded that inhibition of dimer excision plays an important role in the observed heat efects ; UV sensitization, prolongation of the period susceptible to photoreactivation, and inhibition of liquid holding recovery.View full abstractDownload PDF (405K) -
A. OKUDA1974 Volume 15 Issue 3 Pages 140-143
Published: September 01, 1974
Released on J-STAGE: July 14, 2006
JOURNAL FREE ACCESSWhen heat (52°C for 20 min) and ultraviolet (UV, 750 erg mm-2)-treated E. coli B/r cells were subjected to liquid holding and then illuminated with photoreactivating light, their ability to be photoreactivated (photoreactivability) was not changed during 30 hr holding. However, when heattreated cells were incubated in growth medium for 3 hr, exposed to UV, and then subjected to liquid holding for 6 hr, photoreactivability disappeared completely. Such disappearance of photoreactivability was also observed when heat treated cells were incubated in growth medium before UV exposure in the presence of hydroxyurea or chloramphenicol, but not when incubated in buffer. These results suggest that heat-induced lesions, which inhibit dimer excision, are repaired during incubation in growth medium.View full abstractDownload PDF (176K) -
A. OKUDA1974 Volume 15 Issue 3 Pages 144-147
Published: September 01, 1974
Released on J-STAGE: July 14, 2006
JOURNAL FREE ACCESSWhen ultraviolet (UV)-irradiated E. coli B/r cells were subjected to liquid holding and then irradiated with high energy electrons, the survival increased with the holding time. On the other hand, such an increase in survival was not observed when UV plus electron-irradiated cells were subjected to liquid holding. When photoreactivating light was further illuminated after these treatments, photoreactivating effect was completely lost within 3 hr of liquid holding in the former case, but was observed significantly after 3 hr of liquid holding in the latter case. When liquid holding was performed in the presence of caffeine, such an increase in survival and such a loss of photoreactivating effcct were inhibited. They suggest that synergistic killing action of UV and ionizing radiations is partially caused by inhibition of excision-repair mechanism.View full abstractDownload PDF (214K) -
K. IGARASHI, F. YATAGAI, T. TAKAHASHI, A. MATSUYAMA1974 Volume 15 Issue 3 Pages 148-155
Published: September 01, 1974
Released on J-STAGE: July 14, 2006
JOURNAL FREE ACCESSLog-phase cells of E. coli Bs-1 labelled with 3H-thymidine were bombarded with α-particles, carbonand nitrogen-ions of various energies and the LET dependence of the efficiency of DNA single-strand break production (Esb) was investigated. The amounts of radiation energy required for single-strand break production proportionally increased with increasing LET∞ in the range greater than about 90 keV·μm-1. The heavier particle gave an LET∞-Esb curve shifted to the higher LET as compared with that for the lighter particle. The relationship between the restricted LET (LET500) and Esb corrected for δ-rays was represented by the same linear regression curve for the above three kinds of particles. Analysis of the high-LET data in correlation with survival radiosensitivity indicated that the number of particles passed through the DNA strand per D37 decreases with increasing LET, approaching to the unity and the number of single-strand breaks per D37 produced by the track-core effect decreases toward a value of about 3. The results suggest that the traversal of a heavy charged particle of high LET through the DNA strand may produce a double-strand break, which would be of major importance in cell inactivation at high LET, but single-strand breaks produced mainly by δ-rays is not necessarily lethal.View full abstractDownload PDF (420K) -
T. YAMAMOTO, E. YUNOKI, M. YAMAKAWA, M. SHIMIZU, K. NUKADA1974 Volume 15 Issue 3 Pages 156-162
Published: September 01, 1974
Released on J-STAGE: July 14, 2006
JOURNAL FREE ACCESSUranium contents of daily diets and of human urine are examined from inhabitants around a uranium mine and its refinery (Ten-no and Nakatsugo hamlets, Kamisaibara Village, Okayama Pref.). Those from Ukainishi and Tomiyoshi areas (Mitsu and Tsudaka Town, Okayama Pref.) are served as controls. The daily diet and human urine was randomly collected in each area. Uranium was assayed by solid fluorimetry after ashing. The means of uranium contents in diet from Ten-no and Nakatsugo were 4.55 and 2.86 μg/day/person, respectively, while the means from control areas were 1.02 (Ukainishi) and 0.86 (Tomiyoshi) μg/day/person. Urinary uranium levels from Ten-no and Nakatsugo were 0.14 and 0.07 μg/day/person, respectively, while it was 0.01 μg/day/person in both control areas. No seasonal variations were observed in both dietary and urinary uranium of two test areas nor those of control areas.View full abstractDownload PDF (267K) -
T. KANKURA, W. NAKAMURA, H. ETO, M. NAKAO1974 Volume 15 Issue 3 Pages 163-165
Published: September 01, 1974
Released on J-STAGE: July 14, 2006
JOURNAL FREE ACCESSThe suppression of radiation-induced increase of sodium uptake by warming at 37°C is said to reflect a recovery process of radiation-induced alteration of membrane permeability. SH compounds (AET, MEA and BAL) failed to affect the recovery process by warming. Bovine serum albumin caused an immediate decline of the radiation-induced sodium uptake, followed by further decline during the incubation at 0°C and 37°C. NaF caused an immediate decline of the sodium uptake and reduced upon further incubation at 37°C to the level of the non NaF-treated, irradiated cells. The immediate decline of the sodium uptake seen by albumin and NaF at a temperature as low as 0°C, together with failure of interference of the recovery process by inhibition of glycolysis and alteration of cellular ATP level, of the previons study, suggest that the effects of warming on the membrane permeability is more likely to be a physicochemical process rather than a metabolic process.View full abstractDownload PDF (152K) -
Y. H. NAKANISHI, M. KUWABARA, G. YOSHII1974 Volume 15 Issue 3 Pages 166-168
Published: September 01, 1974
Released on J-STAGE: July 14, 2006
JOURNAL FREE ACCESSCalf thymus deoxyribonucleoprotein solution was gamma-irradiated at a dose of 1, 000 KR, and negatively stained samples were examined by electron microscopy. The irradiated DNP fibers showed a reduction in their diameter as well as a fragmentation of the fibers.View full abstractDownload PDF (140K)
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