During the project the collaborating laboratories integrated their research in a manner which allowed the investigation of the induction of numerical chromosome changes using mouse/human cell hybrids, hamster and human fibroblasts and human lymphocytes. These cell types were utilized with a variety of protocol variations which included:
1) Time of exposure in the cell cycle
2) Sampling and fixation times
The endpoints developed and evaluated for the quantification of the induction of numerical changes included:
i) Micronucleus induction, with evaluation of the nature of the chromosomal material using the antikinetochore Crest antibody and centromeric probes
ii) Chromosome counts of the whole karyotype
iii) Counts of specific chromosomes using whole chromosome paints in metaphase cells and centromeric probes in interphase cells.
The results obtained demonstrated that micronuclei may be induced by ionising radiation at doses as low as 0.5Gy of both X-ray and proton irradiation. The micronuclei induced were predominantly kinetochore and centromere negative, indicating that they arose from chromosome structural aberrations. When micronuclei were classified into those arising from structural aberrations and those arising from whole chromosome loss it is clear that both types are induced by ionising radiation in a dose-dependent manner.
Funding SchemeCSC - Cost-sharing contracts