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Mitotic perturbation and G₂ cell chromatid aberrations^*

John R.K. Savage; D.G. Papworth

MRC Radiobiology Unit, Chilton, Didcot, OX11 ORD, U.K.

ABSTRACT

There is no cell system in current usage that has a uniform radiosensitivity for the production of chromatid-type aberrations. Consequently, aberration frequencies fluctuate with sample-time after exposure; there is no unique yield to set against absorbed dose.
Given this situation, the observed yields, and their time-profiles, are subject to modification by cell kinetic factors, in particular, the mitotic delay which inevitably accompanies all clastogenic treatments.
This paper discusses some cell-cycle modelling methods which attempt to explore the effects of these perturbations on aberration frequencies, and which, in time, may allow us to correct observed yields to obtain reliable, and useable, scores of chromatid structural changes.

Keywords: mitotic perturbation; cell chromatid aberrations.

REFERENCES

Dewey, W.C. and Highfield, D.P. (1976). G2 block in Chinese hamster cells induced by X-irradiation, hyperthermia, cyclophosphamide, or actinomycin-D. Radiat. Res. 65: 511-528.

Easton, D.M. and Schneiderman, M.H. (1987). Prediction of X-ray induced mitotic delay and recovery of G2 cells. Cell Tissue Kient. 20: 379-386.

Elkind, M.M. and Whitmore, G.F. (1967). The Radiobiology of Cultured Mammalian Cells. Gordon Breach, N.Y., pp. 615.

Lea, D.E. (1946). Actions of Radiations on Living Cells. 1st edn. Cambridge University Press, Cambridge, pp. 402.

Savage, J.R.K. (1989). The production of chromosome structural changes by radiation: An update of Lea, (1946), Chap. VI. Brit. J. Radiol. 62: 507-520.

Savage, J.R.K. and Papworth, D.G. (1973). The effect of variable G2 duration upon the interpretation of yield-time curves of radiation-induced chromatid aberrations. J. Theoret. Biol. 38: 17-38.

Savage, J.R.K. and Papworth, D.G. (1991). Excogitations about the quantification of structural chromosomal aberrations. In: Advances in Mutagenesis Research. 3. (Obe, G., ed.). Springer Verlag, Berlin, pp. 162-189.

White, R.A. (1981). A review of some mathematical models in cell growth. In: Developments in Cell Biology. 8. (Rotenberg, M., ed.). Elsevier, Amsterdam, pp. 243-261.

* This paper was presented at the ICRO/UNESCO International Training Course `Molecular Organization of the Eukaryotic Chromosome in Relation to the Induction of Chromosome Aberrations" organized by Professor Günter Obe, Dr. Máximo E. Drets and Dr. Gustavo A. Folle, held September 16-28, 1991 at Montevideo, Uruguay. It is the fifth in a series of five papers from this course published in the Brazilian Journal of Genetics.