Accelerating action of tea on mouse skin carcinogenesis

The effect of different tannin-containing aqueous solutions on the carcinogenic action of benzo(a)pyrene (BP) on the mouse skin was investigated. It was found that the appearance of tumours was accelerated in mice treated with either tea or an oak extract after a single application of BP. The time of appearance of tumours in mice treated with gallic acid or tannic acid after treatment with BP was similar to that in the group treated with BP alone. The overall incidence of tumours was similar in all five groups.

Ontogeny of the phytohemagglutinin response of fetal piglet thymic and splenic lymphocytes

Lymphocytes derived from 72- to 90-day-old fetal piglet thymuses respond in vitro to phytohemagglutinin quantitatively greater than do spleen cell lymphocytes.

Development of bactericidal capacity and phagocytosis-associated metabolism of fetal pig leukocytes

Evidence that the bactericidal ability and the stimulated oxidative metabolism of leukocytes appear in parallel during fetal development of the Minnesota Miniature pig has been obtained by application of the techniques applied to studies of human cells. It was demonstrated that leukocytes from 87- to 90-day fetuses were fully capable of ingesting Staphylococcus aureus but greatly diminished in bactericidal capacity as compared to leukocytes of older fetuses and adults. Although resting levels of oxygen consumption and hexose monophosphate pathway activity of leukocytes from the younger fetuses compared well with those of leukocytes from older animals, the phagocytosis-stimulated increments of metabolism were much less at 87 to 90 days of gestation than at later developmental stages. Both bactericidal capacity and increased metabolism of leukocytes reach adult levels by 100 days of gestation (normal gestation period of 115 to 120 days). Acrylamide gels stained for reduced nicotinamide adenine dinucleotide (NADH) and NADH phosphate (NADPH) diaphorase activity after disc electrophoresis of leukocyte extracts revealed normal mobility and intensity of NADH diaphorase bands. Three NADPH diaphorase bands were present in adult leukocyte extracts. Only the fast-migrating NADPH diaphorase band of 87- to 90-day cells stained with decreased intensity. This "deficiency" was no longer present at the later fetal period. The fast-migrating NADPH diaphorase band may represent an electron transfer protein which functions in cyanide-insensitive respiration of the leukocytes of the pig.