Abstract
The role of cellular synchronization using Colcemid as pretreatment for combined chemoradiotherapy was investigated. C6 rat brain tumor cells were cultured in RPMI 1640 medium containing 10-5-10-7 mol. of Colcemid for 24 hours. The basic cell kinetics were analysed with pulse-cytophotometer, which facilitated the analysis of tumor cell cycle phase distribution according to the DNA content. The effect of Colcemid depended on the concentration. The minimal concentration showing continuous blocking during 48 hours after removal of the drug was 10-6 mol. G1 fraction with 2C DNA content was reduced from 74% to 36%. G2, M phase with 4C DNA content increased from 9% to 28%. S-phase-cells increased from 17% to 31 %. Polyploid cells in the tetraploid cell cycle were recongized. Further studies are necessary for ellucidating the mechanism about the leakage of some arrested cells in metaphase into tetraploid cell cycle system. The resting 36% cells in G0 — G1 peak with 2C DNA content might be evaluated as diploid G0 fraction.
