1966 年 1 巻 2 号 p. 71-75
On the basis of results of recent experiments carried out by the members of the National Institute of Radiological Sciences, some of recent problems on recovery from radiation injuries in biologically important molecules, cells and whole organisms are briefly reviewed. At molecular level, nature of enzyms which are responsible for repair from DNA damage in microorganisms is investigated by the workers of the laboratories of Dr. K. Suzuki and Dr. S. Nakai. In order to analyze mechanism of chromosome break and reunion, fine structure of chromosomes is studied by Dr. Y. H. Nakanishi. Using synchronous cell culture system, Dr. Terasima has examined in detail effects of fractionation of radiation dose on survival of cells, and has quantitatively demonstrated recovery from sublethal damage by irradiation under various conditions. Drs. Nakamura, M. Seki, S. Ichii, T. Yamaguchi, T. Tsuchiya, K. Hirashima and their collaborators are studying recovery processes in hematopoietic tissue of animals in relation to endocrine system, immunological responses and bone marrow transplantation etc. by their own methods. Pharmaceutical research is worked out by Drs. T. Hino and M. Shinoda. Cell population kinetics in the critical organs during recovery period from radiation damage at different temperatures are studied out with poikilothermic vertebrates by Drs. H. Etoh, Y. H. Taguchi and N. Egami.
From these results, importance of consideration of recovery factors in estimation of risks from radiation is pointed out as conclusion.