Variations in Survival Time after Whole-Body Radiation at Two Times of Day

Abstract

Rats, anesthetized with sodium pentobarbital, given 900 roentgens of x-radiation over the entire body, survived more than 130 days when the radiation was given in the morning. The same dosage killed all the animals within 13 days when the radiation was given at night.

Establishing a Murine Model of the Hematopoietic Syndrome of the Acute Radiation Syndrome

“…Chronoradiosensitivity of mice and rats has been recognized since the early 1960s (Pizzarello et al 1963, Pizzarello et al 1964, Nelson 1966, Hellwig and Rosenkranz 1968, Haus et al 1974, Haus 2002), and has been suggested to be a useful guide to time delivery of radiotherapy in humans for malignancy. In rats and mice, mortality was shown to be higher when irradiation was delivered during the night time hours (Nelson 1966) and/or during the early light hours (Pizzarello et al 1964, Hellwig and Rosenkranz 1968, Haus 2002).…”

Circadian Rhythmicity in the Effect of Irradiation on the Endogenous Colony Formation in the Spleen of Irradiated Mice

“…As other investigators (Menaker 1964, Pizzarello et al 1964 reported it is probable that daily rhythms in radiosensitivity were not found owing to non-observance of certain experimental conditions.…”

“…In mice and rats a higher mortality was found during irradiation at night than during irradiation by day (Pizzarello, Witcofski and Lyons 1963, Pizzarello, Isaak, Chua and Rhyme 1964, Peters 1963, Darenskaya 1965, Fochem, Michalica and Picha 1965, Nelson 1966.…”

Circadian Rhythmicity in the Sensitivity of Two Strains of Mice to Whole-Body Radiation

“…It is clear that, given a cycle of changing radiosensitivity such as our present results make more explicit, overall mortality may well not be different for two treatments unless first, a dose is used which is very near to being lethal and secondly, the treatments are given at just the right phases in the cycle of sensitivity (or capacity to recover). It is evident in view of the data presented here that Pizzarello et al (6) were lucky on both counts. In any case it will be better to assay the effects of the treatments not simply by overall mortality, as we were able to do originally, but by its effect on the full time-course of survival.…”