TYPES AND RATES OF X-RAY-INDUCED CHROMOSOME ABERRATIONS IN HUMAN BLOOD IRRADIATED IN VITRO

Abstract

Metaphase aberrations were scored in first in vitro divisions of leucocytes cultured from human blood irradiated with hard X rays immediately after it was drawn. Only chromosome-type, as opposed to chromatid-type, aberrations were found in the irradiated material. Control cells yielded a maximum of 0.0023 chromosome-type breaks/cell. Deletions, rings, dicentrics, and symmetrical translocations were induced in the irradiated chromosomes. Deletions increased linearly with dose with a coefficient of production of 0.11 [plus or minus] 0.012 x 10-2 deletions/cell/r. Dicentrics increased roughly as the square of the dose with a coefficient of production of 0.45 x 10-5 dicentrics/cell/r2. These coefficients agree well with those for Tradescantia microspores. The results of these studies on irradiated blood, which approximate in vivo irradiations as closely as is possible at present are discussed in relation to previous work on aberrations in human tissue culture cells. The possible use of chromosome aberration analysis of peripheral leucocytes as a "biological dosimeter" is described.