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Volume 14 (1973)
- Issue 4 Pages 339-
- Issue 3 Pages 209-
- Issue 2 Pages 115-
- Issue 1 Pages 1-
Volume 14, Issue 1
Displaying 1-5 of 5 articles from this issue
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Y. YOSHIZAWA, K. UEDA1973 Volume 14 Issue 1 Pages 1-8
Published: March 15, 1973
Released on J-STAGE: July 14, 2006
JOURNAL FREE ACCESSA total of 333 pregnant mice (ddY strain) and their 2759 fetuses were used. When the radiation-induced delay of ossification was used as an indicator of radiation effects on fetal growth, the gestation ages 8 and 16 days were found to be two radiosensitive stages. The degree of the delay of ossification was enhanced with increasing the radiation dose. However, the radiation-induced delay, estimated from the number of ossificated caudal vertebrae on day, was only slightly dependent on the dose rate (1 R/min to 100 R/min). The number of ossificated caudal vertebrae in response to fetal irradiation was paralleled to the body weight of fetus.View full abstractDownload PDF (296K) -
J. HAYAKAWA, T. TSUCHIYA, I. TAMANOI, M. NUMATA1973 Volume 14 Issue 1 Pages 9-17
Published: March 15, 1973
Released on J-STAGE: July 14, 2006
JOURNAL FREE ACCESSThe in vitro iron uptake by erythrocytes was examined as an indicator of radiation effects on erythropoiesis in mice. Erythrocyte suspensions were incubated with 59Fe, previously bound to serum for 3 hours at 37°C. The changes of the iron uptake within 48 hours following X-irradiation of 25 R and 50 R showed biphasic patterns. The reduction of the uptake at 18-20 hours after irradiation correlated exponentially with the exposure doses from 25 R to 200 R.
In animals irradiated with 200 R, the recovery from the radiation-induced depression of the iron uptake by the in vitro method was delayed by two days from that estimated by the in vivo iron uptake studies. Since the in vitro uptake is mostly due to young reticulocytes present in the erythrocyte suspension, the delay of two days in recovery is likely to be attributed to the time required for erythroblasts in bone marrow and spleen to mature and be released to blood as reticulocytes. The in vitro iron uptake reflects the reticulocyte counts, and can be a simple and reliable indicator for radiation-induced disturbances of erythropoiesis.View full abstractDownload PDF (363K) -
H. TANOOKA, F. MAKINO1973 Volume 14 Issue 1 Pages 18-30
Published: March 15, 1973
Released on J-STAGE: July 14, 2006
JOURNAL FREE ACCESSAbility of various DNA and biopolymers to compete with genetic marker-bearing DNA in the Bacillus subtilis transformation system was studied. Among tested polymers, only DNA exhibited the competing ability. Treatment of DNA with physical or chemical agents destroyed the competing ability. The competing ability of the treated DNA was compared with other abilities of the same DNA, i. e., transforming ability on another marker and ability to compete with 3H-labeled marker DNA at incorporation into host cells. A parallelism was found between the transformation-competing ability and the incorporation-competing ability, while a parallelism was not necessarily hold between the competing ability and the transforming ability depending upon the agent used. From the modes of actions on these abilities of DNA, the agents were classified in two major groups, I) those which inactivate the trasforming ability of DNA, but exert little effect on its competing ability (e. g., ionizing radiation exerting indirect action, UV, nitrogen mustard, nitrous acid, 4 HAQO, DNase I, sonication) and II) those which inactivate the transforming ability of DNA as well as its competing ability (e. g., ionizing radiation exerting direct action, shearing). Nature of molecular damages caused by these agent was discussed.View full abstractDownload PDF (450K) -
K. KODAIRA, A. TSUMURA, H. KOBAYASHI1973 Volume 14 Issue 1 Pages 31-39
Published: March 15, 1973
Released on J-STAGE: July 14, 2006
JOURNAL FREE ACCESSWater-cultured rice plants were exposed to 89Sr or 137Cs through roots for five days at their various growth stages and continued to grow until harvest. The harvested grains were radiochemically analysed and the concentration factors were calculated.
The maximum uptake of 137Cs in the grains was found at the booting stage, while that of 89Sr was at the flowering stage. The Cs uptake was 400 times higher at the booting stage, and 30 times higher at the flowering stage than those with Sr.
The growth stage dependency of the uptake of Sr and Cs was the most important factor for a selective enrichment of Cs in rice grains.
The specific affinity of Cs to cell sap and that of Sr for membrane substances of rice grains probably caused a selective redistribution inside the plant body.View full abstractDownload PDF (377K) -
K. KAWASE, E. YOKOYAMA1973 Volume 14 Issue 1 Pages 40-48
Published: March 15, 1973
Released on J-STAGE: July 14, 2006
JOURNAL FREE ACCESS90Sr and 137Cs contents of soils, mostly from radioactive fallouts of the past nuclear explosions, were estimated at 15 locations in Niigata Prefecture. Fifteen locations include paddy fields, meadow, grass fields, forest and dried lagoon. 90Sr contents of the soils, except forest and dried lagoon, ranged from 81 to 315 mCi/km2 and 137Cs ranged from 234 to 451 mCi/km2. These results indicate that the soils except forest and lagoon were highly contaminated with 90Sr and 137Cs from radioactive fallouts. The high activities of 90Sr and 137Cs were noted in rice paddy fields. 90Sr of 316 mCi/km2 of Muramatsu Town and 137Cs of 451 mCi/km2 of Gosen City are probably the highest values recorded in Japan. These high values may reflect the high annual rainfall of these areas. Relatively low 90Sr and 137Cs levels of forest soils and dried lagoon suggest that 90Sr in strongly acidic, sandy and low humic soils were washed away rather easily by water and that 137Cs in very reductive paddy soil and in volcanic ash soil were also easily removed by water. The distribution of 90Sr and 137Cs in relation to various depth of soils indicates that the monitering of two nuclides in soils should be carried out from the soil sample dug up to 50 cm depth.View full abstractDownload PDF (397K)
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