RESUMO
The inhibiting effect of 11 kinds of ordinary vegetables including eggplant, cucumber, Chinese cabbage, fresh kidney bean, tomato, paprika, spinach, carrot, onion and celery on the formation of N-nitroso compounds was studied. Most vegetables inhibited the formation of N-nitrosodimethylamine when am-inopyrine and nitrite added to the vegetable juice and citric acid buffer were incubated in a model system simulated stomach condition (pH 3.00, T 37℃) for 1 hr. The inhibiting rate related to the contents of ascorbic acid in the vegetables ranged from 32.70% to 97.61%. Onion, fresh kidney bean, spinach and eggplant inhibited the formation of N-nitrosodimethylamine effectively with the inhibiting rate of 77.91%, 73.40%, 57.48% and 30.75% respectively (the inhibiting effect of ascorbic acid contained in the vegetables had been excluded). The relationship between the dose and the inhibiting effect of onion, fresn kidney bean, spinach and eggplant was good with the correlation coeffecient 0.756, 0.917, 0.607 and 0.801 (p
RESUMO
In our experiment the typical structure of Peyer's patches (PP) of rabbits was absent in neonatal animals, but after birth, it developed gradually and rapidly. On the 6 th day, the lymphoid structure of PP appeared and two types of lymphocytes, T and B, were observed in PP. At the same time, there were some microfold cells in the epithelium of the dome. By half a month, the lymphoid structure of PP matured histologically and later on it was more developed and PP gradually increased in size during the growth of the rabbit. The PP of a 3 month old rabbit were similar to those of the mature animals, but no involution of PP appeared at the stage of sexual maturity.The development of PP in rabbits is closely related to the first antigenic stimulation from the intestinal contents, and T, B lymphocytes and macrophages are present at the start of PP formation. In addition, there is no involution of PP in the adult rabbit. These features of PP in rabbits are different from those of the bursa of Fabricius, so it is inappropriate to regard the PP of rabbits as the homologue of the avian bursa of Fabricius.