[Effect of Ara-C on chick embryo erythropoiesis: erythrocyte differentiation].

The present work studies the possibility of inducing an alteration in the erythropoietic switchover from primitive to definitive red cells in the chicken embryo by means of Cytoarabine (Ara C). To this purpose two different concentrations of Ara C were injected into fertilized chicken eggs after 94 hours of incubation. Optical microscopy was used in the morphological analysis of the blood smears taken from treated and control embryos on the 7th and 8th day of incubation (state 30 and 33 in the Lillie Table).

Betamethasone-induced lecithin release in vitro from the fetal membranes.

Lecithin release from fetal membranes and placental tissue was assayed in basal conditions as well as under betamethasone administration. In the absence of the steroid, amnion and chorion released lecithin as a function of incubation time. Both tissues responded to betamethasone by increasing the lecithin release, the amnion exhibited a higher basal level and a greater responsiveness to the hormone than the chorion.

[Normal human gingiva. In vitro observations].

By comparing human embrional gum fragments cultivated in vitro using the technique of Wolff and Haffen with adult gum fragments, the advantages of the fetal gum are evident; and this could serve as a point of departure for an analysis of the differentiation and the cytophysiology of this structure, which is still not very well known.

"In vitro" effect of progesterone on alpha-L-fucosidase activity of human endometrium.

Alpha-L-fucosidase activity was found to be increased in organ cultured normal endometrium and in endometrial adenocarcinoma compared with non cultured tissue. The enzyme activity was lowered with addition of progesterone to the medium. Non cultured adenocarcinoma showed a higher activity compared with non cultured normal endometrium.