Modes of Radiation Death in the Chick Embryo: I. Acute Syndromes

In the chick embryo irradiated after 6 days of incubation. mortality within 12 days following acute exposures to Co/sup 60/ gamma radiation roughly falls into intervals of 0 to 1 day, 2 to 5 days, and 6 to 12 days.These time periods are closely correlated with the appearance of certain grossly visible pathologic conditions observed in decedents. The pooling of blood in the large veins is associated with deaths occurring within 24 hours after irradiation. localized accumulations of fluid are principally characteristic of deaths between 2 and 5 days, whereas hepatic lesions as well as evidence of hematopoietic failure predominste among deaths between 6 and 12 days. This association between observed pathology and mortality period suggests a method of partitioning the acute effects that are expressed withia 12 days after irradiation. Deaths occurring within each of the three non-overlapping periods are assumed to represent the attainment of lethal bounds by independent injury processes, the linetics of which are reflected in the Joint behavior of the experimental variables associated with deaths within that period. (auth)