The effect of x-irradiation of the progress of strain U-12 fibroblasts through the mitotic cycle
The effect of irradiation on Strain U-12 fibroblasts was studied. The administration of 500 r inhibited mitosis almost immediately, whereas the specific activity of DNA and the number of cells synthesizing DNA were not reduced markedly until 18 to 24 hr following the irradiation. RNA synthesis was not reduced at any interval observed. Twelve hours after irradiation mitotic figures again appeared and increased in frequency to above the normal level 18 to 20 hr after irradiation. The increase in mitotic index was found to be caused both by an increase in the cells entering and by a decrease in cells leaving mitosis. The cells entering mitosis 12 or more hr after irradiation appeared to consist of cells that had accumulated in the G2 period 6 to 12 hr after irradiation and cells coming from the synthetic period that were able to pass through the G2 period without delay 12 hr after irradiation. Cells entering mitosis 12 or more hr after irradiation were found to spend long periods trying to divide but were most often unsuccessful and, in many cases, they produced a multinuclear giant instead of two normal daughter cells.
- Research Organization:
- Western Reserve Univ., Cleveland
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-16-026760
- OSTI ID:
- 4809748
- Journal Information:
- Annals of the New York Academy of Sciences, Journal Name: Annals of the New York Academy of Sciences Journal Issue: 2 Vol. 95; ISSN 0077-8923
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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