Cellular kinetics in blood-forming organs after x irradiation (in Japanese)
The total number of lymphocytes in the thymus markedly decreased during the first 5 days after x irradintion. Lymphocyte depletion in the first phase was greatest in the thymus. This suggests that the thymic lymphocytes may be more sensitive than those of other lymphoid organs. Moreover, the most pronounced repopulation of thymic lymphocytes 10 days following the initial decrease suggests an important role of thymus in the recovery from irradiation damage of other lymphoid organs. The depletion and repopulation of lymphocytes in the three lymphoid organs and bone marrow were compared by estimating the number of lymphocytes that were contained in 1 mg of each organ at various periods after x irradiation, The degree of lymphocyte depletion at the earliest periods following irradiation was the highest in bone marrow, followed by the thymus, spleen, and mesenteric lymph nodes, in decreasing order of depletion. The bone marrow lymphocytes may be more radiosensitive than thymic lymphocytes. The transient increase in lymphocyte numbers following the early depletion was also the greatest in the bone marrow, followed by the thymus. This suggests that bone marrow and thymic lymphocytes play an important role as stem cells. Lymphocytes were classifled into the three types according to their cell diameter (small: less than 9.0 mu , mediumsized: 9.1 to 13 mu , large: larger than 13.1 mu ), and the changes in their absolute number after irradiation were observed. The three types of lymphocytes in each organ exhibit an initial sharp decrease, followed by a transient, marked repopulation 10 days after irradiation. The repopulation of large and medium-sized lymphocytes restored the cell number beyond the control level, but the increase of small lymphocytes failed to restore the cell number to the control level. Thus, the repopulation of large and medinm- sized lymphocytes tended to precede that of small lymphocytes in all of the three lymphoid organs. A marked proliferation of plasma cells in the mesenteric lymph nodes and spleen was seen after 7 days; however, no proliferation of these cells was observed in the thymus and bone marrow. (auth)
- Research Organization:
- Yamaguchi Univ., Ube, Japan
- NSA Number:
- NSA-29-010439
- OSTI ID:
- 4404438
- Journal Information:
- Igaku Kenkyu, v. 42, no. 3, pp. 150-158, Journal Name: Igaku Kenkyu, v. 42, no. 3, pp. 150-158; ISSN IGKEA
- Country of Publication:
- Japan
- Language:
- Japanese
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