The dose response relationship obtained at constant irradiation times for the induction of chromosome aberrations in human lymphocytes by cobalt-60 gamma rays

Abstract

The induction of unstable chromosome aberrations in human peripheral blood lymphocytes exposed in vitro to protracted doses of cobalt-60 radiation is presented. Four dose response curves have been produced using constant exposure times of 1,3,6, and 12 h. The data fit well to the linear quadratic model and the yield coefficients have been compared with those obtained for acute (less than 10 min) exposure. The quadratic coefficient is dependent on irradiation time and decreases approximately as predicted by Lea and Catcheside's G-function hypothesis. The possibility of a small proportion of much longer lived breaks is discussed. For purposes of biological dosimetry it is sufficient to assume a mean time of 2 h and a single exponential function for the repair of lesions when relating the effects of brief and protracted exposure.

Histological and ultrastructural analyses of mole rats lung cells exposed to ultraviolet radiation

“…Various types of damage induced in these molecules lead to significant biological effects including cytotoxicity, mutations and alterations in cell signaling pathways (Barker, Weinfeld, Zheng, Li, & Murray, 2005;McMillan et al, 2008). As a result of this effect leading to chromosomal mutations and cytotoxicity, cancer development occurs (Lloyd, Edwards, Prosser, & Corp, 1984).…”

Modelling radiation-induced biological lesions: from initial energy depositions to chromosome aberrations

“…A large amount of work has been produced on the role of DNA damage complexity in determining radiation induced biological effects [14,20,21,[58][59][60][61][62]. Concerning chromosome aberrations, Sachs and Brenner [63] have provided a quantitative formalism that allows us to describe the induction of severe dsb, and the subsequent production of chromosomal exchanges; from comparisons with experimental data, the authors draw the conclusion that "a hybrid model in which severe dsb contribute to the high-LET aberration yield cannot be ruled out".…”

Biological Dosimetry of Ionizing Radiation

“…If the time of exposure is long, the G-function may be reduced to zero (Lloyd, 1984). Therefore, in case of fractioned irradiations if the time between exposures is greater than 6 hours, the different exposures will be considered as separate and the effect as additive.…”