Observations of Radiation-induced Chromosome Fragment Loss in Live Mammalian Cells in Culture, and Its Effect on Colony-forming Ability

Abstract

Our preceding paper (Grote, Joshi, Revell and Shaw 1981) described a method for the direct scrutiny of live cultured mammalian cells with a microscope, and reported that all diploid Syrain hamster kidney fibroblast cells (BHK 21 C13) of a smaple given 1.4 Gy [gray] of 220 kV X-rays in G1 reached post-radiation mitosis without discernible abnormality, but then diverged in observed behavior: descendent cells from some 1st mitoses continued to proliferate normally while cells from other 1st mitoses behaved abnormally and produced either slow-growth or stop-growth colonies. This paper completes our study of the same irradiated cell sample, and shows that these post-mitotic differences in clonogenic ability were related to acentric chromosome fragment losses at post-radiation mitosis, which were detected in live daughter-cell pairs as micronuclei. The proportion of live daughter-cell pairs scored as deficient was at least 80% of the proportion of comparable fixed-and-stained mitoses with detected acentric fragments.