Granville W. Hudson

The effect of orally administered fat emulsion on survival of the irradiated rat.

A large dose of total-body X-irradiation to rats results in severe anorexia for several days. Therefore, the possibility exists that decreased caloric intake may contribute to the factors responsible for mortality. Attempts at forced feeding by Smith et al. (1), using a semifluid diet of protein hydrolyzate, and by Smith and co-workers (2), using a casein digest, failed to prolong survival rate. The forced feeding actually resulted in a higher mortality rate and shorter survival time than in irradiated nonfed controls. More recently, Smith and Tyree (3) confirmed and extended their earlier findings. Since fat furnishes a greater number of calories per gram than either carbohydrate or protein, it seemed desirable to attempt forced feeding of irradiated animals by daily administration of relatively small amounts of an easily digestible fat. For this reason an attempt was made to prolong survival time and to reduce weight loss in rats given LD50, or higher, doses of irradiation by oral administration of a thoroughly homogenized emulsion of cottonseed oil. The evidence showed that the forced feeding of fat was detrimental and resulted in shorter survival times than similarly irradiated controls given only water.

Effect of X-Irradiation on Cecal Flora of the Rat.

Summary 1. The effect of total-body x-irradiation (825 ir in air) on the cecal flora of rats has been studied. Numbers of lacto-bacilli, coliforms? and azide-resistant organisms in rats fasted 24 hours before and after irradiation were compared to those in pair-fed control rats fasted for the same 48-hour period. The normally predominant lacto-bacilli decreased in number while the coli-forms and azide-resistant bacteria increased. 2. A fasting period of 48 hours elicited no proportional change in bacterial types when the counts were compared with those of normal fed rats. 3. Irradiation itself was responsible, at least in part, for the observed changes.

Effect of Total-Body X-Irradiation on Fat Balance and Liver Lipids in the Rhesus Monkey

Fat balance studies were done on rhesus monkeys irradiated with 325, 400 and 650 r total-body x-irradiation. The postirradiational results were compared with the preirradiational values of the same monkeys and with those obtained in pair-fed controls. No defect in fat absorption was found due to the irradiation. Increased fecal fat loss after irradiation was observed in both irradiated and nonirradiated animals. Monkeys given 650 r had liver lipid concentrations similar to their pair-fed controls. These analyses were done at 12, 96 and 229 days after irradiation. Changes in body weight in all animals paralleled decreases in food intake immediately after irradiation and subsequent increases with recovery. Hematologic studies showed the usual decrease in leucocyte count after irradiation. One monkey given 650 r was killed 12 days postirradiation because death was imminent; all other animals survived the irradiation.