- were signalled to remain alive by their neighbours. Boukamp, P., Stanbridge, E. J., Foo, D. Y., Cerutti, P. A.,
- This confirmed Raå ‚s general hypothesis that sur-and Fusenig, N. E., 1990, C-Ha-ras oncogene expression
- vival factors secreted by neighbours prevent initiation in immortalised human keratinocytes (HaCAT) alters
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- pathway could be avoided if conditioned medium Chang, W. P. and Little, J. B., 1992, Delayed reproductive
- containing antioxidants was added to isolated cells death as a dominant phenotype in cell clones surviving
- deprivedofsurvival signaloftheirneighbours. X-irradiation. C arcinogenesis, 13, 923- 928.
- Applied to the results in this study this could mean Clutton, S. M., Townsend, K. M. S., Walker, C., Ansell,
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- secrete a death signal or that they fail to secrete a ary bone m arrow cultures. C arcinogenesis, 17, 1633 -1639.
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- would seem to mitigate against the latter possibility. chromosom es; are they induced by a transferable sub-
- Lloyd and M oquet (1985) and several earlier authors stance in the plasm of persons exposed to total body
- (e.g. Goh and Summer 1968, Hollowell and Littlefield irradiation? Radiation Research, 35, 171 -181 Hollowell, J. G. and Littlefield, L. G., 1968, Chromosome
- 1968, Scott 1969,), showed evidence for a factor in damage induced by plasma of X-rayed patients: an
- irradiated plasma which was clastogenic, but nothing indirect eåect of X-ray. P roceedings of the S ocietyfor
- seems to have been done to try to identify the factor E xperim ental B iology and M edicine, 129, 240- 244.
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- proposed by Lloyd and M oquet (1985) was that 1993, Control of lens epithelial cell survival. The Journal of Cell Biology, 121, 899- 908.
- irradiated plasma seemed to hasten the transit of Ishizaki, Y., Burne, J. F. and Raff, M. C., 1994, Autocrine
- cells through the first post addition cell cycle. With signals enable chondrocytes to survive in culture. The
- the information now available to us regarding check-Journal of Cell Biology, 126, 1069 -1077
- point controls during the cell cycle, this field may Jamali, M. and Trott, K.-R., 1996, Increased m icronucleus
- possibly be worth revisiting. frequency in the progeny of irradiated Chinese hamster cells. I nternational J ournal of R adiati on B iology, 69, 301 -307.
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- interesting. No eåect was seen with medium har-S. A., Marsden, S. J. and Wright, E. G., 1992,
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- occurred with a very radiosensitive cell line (SW 48). alpha-particle irradiation. N ature (L ondon), 355, 738 -740.
- But medium from irradiated epithelial cells could kill
- Kadhim, M. A., Lorimore, S. A., Townsend, K. M. S., Goodhead, D. T., Buckle, V. J. and Wright, E. G.,fibroblasts while medium harvested from irradiated 1995, Radiation-induced genomic instability: delayedfibroblasts had no eåect on epithelial cells. This again cytogenetic aberrations and apoptosis in prim ary human
- suggests that a death factor is secreted by some cell bone m arrow cells. I nternational J ournal of R adiati on B iology,
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- low doses in these cell lines. This refers data showing proliferation in prim ary cultures of rabbit endometrial
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- of the lines tested would support a hypothesis that of Sciences (USA) , 83, 4784 -4788.
- the low dose hypersensitivity is a cellular response
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International Journal of Radiation Biology
Volume 71, 1997 - Issue 4