Acute Lethality in Guinea Pigs Following Respiratory Exposure to 85Kr

Abstract

Guinea pigs were exposed via the respiratory tract for 12 hr to E5Kr concentrations ranging from 54 to 520 ,uCi/cms and observed for 60 days or until death, whichever occurred first. The 30-day median lethal exposure was 4450 (pCi/cm3) hr which corresponds to estimated doses of 316 rads to the bone marrow, 340 rads to the whole body, and 7876 rads to the lungs. The marrow and whole-body doses, times of death and the gross clinical and necropsy observations were consistent with death by the "hematopoietic syndrome" but lung injury was dominant in animals that survived for more than 30 days. The whole-body and marrow doses delivered at the median lethal exposure and the observed times of death are similar to those reported in X-or gamma-radiation lethality studies.

Inhalation exposure methodology.

“…Physical comfort of the animal requires a tolerable seal around the neck. Two systems in use are inflatable collars (12,35) and thin rubber membranes having a small hole that stretches to accommodate the neck. A wide, soft support beneath the neck may be necessary to prevent choking the animal.…”

Leakage testing of medical radium sources

“…An estimate of the time taken for radon gas released in tissue to be removed from the body can be made by considering the human and animal data on another inert gas, krypton-85. The literature on the kinetic behaviour of krypton-85 has recently been reviewed by Kirk and Morken (1975). Most investigations have involved the injection of krypton-85 in solution either directly into the tissue or into the arterial blood supply to the tissue followed by a study of the clearance curves.…”

Inhalation exposure of animals.

“…Head-only exposure systems are typified by those described by Stuart (14) for dogs, by Kirk, Rehnberg, and Morken (15), and by R. G. Thomas (16) (24). Nasal tubes for inhalation exposure of donkeys are described by Albert et al (25).…”

“…Physical comfort of the animal requires a tolerable seal around the neck. Two systems in use are inflatable collars (15,16) and thin rubber membranes having a small hole that stretches to accomodate the neck. The seal must be soft and conform to the noncircular crosssection of the neck.…”