A re-examination of the effects of ionizing radiation on lifespan and transformation of human diploid fibroblasts
Language: 
English
Abstract: 

Human diploid fibroblasts, strain MRC-5, were sequentially irradiated with 60Co gamma rays at intervals during their in vitro lifespan. The results indicate that 3 or 6 doses of 1 Gy can increase lifespan, and the same was true for cells treated with 3 doses of 3 Gy. Higher doses (5 x 3 Gy) did reduce growth potential, suggesting either that mid-late passage cells become more sensitive to radiation, or that doses beyond a given threshold reduce population lifespan by multiple cellular hits. The life extension induced by gamma rays might be due to an induced hypermethylation of DNA. Alternatively, oxygen radicals produced by irradiation might trigger an adaptive stress response which would remove damaged macromolecules and thereby increase the cells' growth potential. Whichever explanation is correct, the results show that the human fibroblast system is not appropriate for the study of the well known effect of ionizing radiation in shortening the lifespan of experimental animals. Contrary to earlier published results, populations of cells treated with cumulative doses of 15 Gy or 18 Gy and held for nearly 3 months after they had reached senescence (Phase III), produced no foci of transformed cells.

Author(s): 
Holliday, R.
Item Type: 
Journal Article
Publication Title: 
Mutation Research
Journal Abbreviation: 
Mutat. Res.
Publication Date: 
1991-11
Publication Year: 
1991
Pages: 
295-302
Volume: 
256
Issue: 
6-Feb
ISSN: 
0027-5107
Library Catalog: 
NCBI Published Medical (?)
Extra: 
PMID: 1722019

Turabian/Chicago Citation

R. Holliday. 1991-11. "A re-examination of the effects of ionizing radiation on lifespan and transformation of human diploid fibroblasts." Mutation Research 256: 6-Feb: 295-302.

Wikipedia Citation

<ref> {{Cite journal | doi = | issn = 0027-5107 | volume = 256 | pages = 295-302 | last = Holliday | first = R. | coauthors = | title = A re-examination of the effects of ionizing radiation on lifespan and transformation of human diploid fibroblasts | journal = Mutation Research | date = 1991-11 | pmid = | pmc = }} </ref>