Abstract
Human leukocyte cultures received X-irradiation at a dose of 400r on the 4th day and fixed on the 6th day. There was an increase from 0.25 to 3.01 per cent in the number of polyploid cells. These were predominantly tetraploids. Microscopic examination revealed that 64 per cent of metaphases observed showed damage. The abnormalities were due to chromosomal breakages, particularly fragments and dicentrics. Counts and detailed analysis of chromosomes in human cells used as controls demonstrated the predominant distribution of euploid elements with 46 chromosomes. These values closely parallel those reported by Ohnuki et al. (1961).
In order to develop a satisfactory culture procedure for rhesus monkey (Macaca mulatta) leukocytes, several technical variations of the routine method were investigated. None of these variations gave satisfactory results for monkey samples, but all were useful for human cells. Such an unusual situation might possibly be induced by differences in the physicochemical and cellular properties of monkey blood and that of man.
