RADIATION-INDUCED CHROMOSOMAL ABERRATIONS AND VARIANT CLONES IN MAMMALIAN CELLS CULTIVATED IN VITRO
A culture of diploid pig kidney cells (57 chromosomes) was irradiated with various x ray dosages. The estimated D/sub o/ of this line is 180 rads. Examnination of chromosome aberrations 24, 27, and 30 hours after irradiation shows that their frequency increases not only with dose but with time after irradiation, this is most marked after the higher doses, so that a theoretical dose-effect relation is approached only after 30 hours. At this time,200 r produces an average of more than one break per cell, and 500 r two or more breaks per cell. Clones started one month after irradiation and kept under cultivation for 8 or 9 months have variously reduced growth rates, persisting chromosome aberrations, and various alterations in the pattern of thymidine uptake. The growth rates of these clones were inversely related to the frequency of aberrations. When the stem line was reirradiated after 9 months cultivation it showed the same temporary retardation of growth as it did originally. Reirradiation of 4 of the 5 surviving clones showed a reduction in growth rate that was of longer dura tion, and more marked in the slower growing ones. The aberrations in the clones, which persisted after several months, were predominantly chromatid breaks, and in many cases the same break was seen repeatedly at a particular site on the chromatid. (26 references.) (auth)
- Research Organization:
- Argonne National Lab., Ill.
- DOE Contract Number:
- W-31109-ENG-38
- NSA Number:
- NSA-16-032729
- OSTI ID:
- 4770226
- Report Number(s):
- TID-16735; UAC-6566
- Country of Publication:
- United States
- Language:
- English
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