Incorporation of thymidine-3H into the activated sea urchin egg with special reference to subthreshold stimulation with an activating reagent

It was ascertained that thymidine-³H added exogenously is incorporated periodically into the nucleus of the fertilized and the artificially activated eggs of Pseudocentrotus, Temnopleurus and Anthocidaris. Eggs stimulated insufficiently with butyric acid did not show any enhancement of incorporation of thymidine-³H. However, repetition of an insufficient stimulation induced incorporation of thymidine to some degree, although no visible cortical changes occurred.     

Rabbit Ileal Loop Response to Strains of Clostridium perfringens

The ligated loop of the rabbit intestine was investigated as a possible experimental model for the study of Clostridium perfringens food poisoning. The method of preparation of the challenge inoculum was important in determining whether a given strain would provoke a response. When cultures were grown for 4 hr at 37 C in Skim Milk (Difco), 14 of 29 type A strains isolated from food-poisoning outbreaks consistently produced exudation of fluid and consequent dilation of the ileal segments. In contrast, 15 of the 18 strains derived from other sources failed to elicit a response. By use of different inoculum preparations, nearly all strains could be made to give at least an occasional positive loop reaction. Diarrhea was not obtained in rabbits by intraluminal injection into the normal ileum or by per os administration of the cultures. Lecithinase, purified and in concentrated culture supernatant fractions, failed to produce a response in the isolated ileal loops.     

Leukocytic response in monkeys challenged with staphylococcal enterotoxin

Sugiyama, H. (University of Chicago, Chicago, Ill.), and E. M. McKissic, Jr. Leukocytic response in monkeys challenged with staphylococcal enterotoxin. J. Bacteriol. 92:349-352. 1966-The feeding of staphylococcal enterotoxin to monkeys elicited a leukocytosis which was evident within 0.5 hr of challenge. The peak neutrophilic leukocytosis was reached in 3 hr, and then subsided so that leukocyte counts were normal within 28 hr. Each of the three serological types of enterotoxin tested induced the same effects. Intravenous injection of enterotoxin slightly above the emetic ed(50) level produced an initial leukopenia followed by a neutrophilic leukocytosis which was maximal 9 or more hr postinjection. With smaller intravenous challenges, some animals responded with a leukopenia followed by a leukocytosis, some with only a leukocytosis, and others with no significant change in total leukocyte counts. The reversal of normal lymphocyte-to-neutrophile ratio toward a neutrophile-predominant white blood cell population occurred in all animals.