[Anatomy of the development of the digestive tract and shape of the external body during the embryonic period of the goat (Capra hircus)].

The purpose of this work has been to establish the pattern of prenatal growth and normal development of the digestive tract and annex glands during goat embryonic stages. 21 embryos with ages ranging from 14 to 34 days (1.69 to 5.

[Differentiation of the crystalline lens in explants of the chicken embryo in the absence of the hypoblast and optical vesicle].

In vitro studies of lens formation in chick embryo have suggested the action of two factors leading the lens induction in the cephalic ectoderm in the absence of optic vesicle: preliminary instructive specific stimulus (homotypic endo-mesoderm) and permissive unspecific stimulus (heterotypic mesenchymes). In order to detect the true capacities of tissues that exert this influence in the cultural condition, series of in vitro experiments were planned. Exclusion experiments: explants including presumptive lens ectoderm were cultured previous to a progressive exclusion of adjacent tissues to trigger lens formation (endoderm, mesoderm and neural tissue), from stage 1 to 7 of HAMBURGER/HAMILTON.

[Cytotoxic properties of anti-kidney antibodies in the chick embryo. I--Antibodies reacting with an antigen specific for the proximal segment of the secretory tubules].

The cytotoxic properties of purified antibodies reacting specifically with an antigen of the proximal secretory tubule cells have been studied. Intravenous injections of these antibody preparations together with complement (Guinea pig serum) into 2-3,5 day old or 12-13 day old chick embryos do not interfere with the development of either the meso-or metanephros. Furthermore, when suspensions of live metanephric cells treated first with anti-proximal segment antibodies and second with complement are cultured under organotypic conditions, one observes the reconstitution of all the characteristic segments (proximal, intermediate, distal and collecting) of the urinary tubule.

Behavior of RNA and protein synthesis during the acclimatization of the carp. Studies with isolated hepatocytes.

1. Carp hepatocytes were isolated by dissociating the liver tissue with collagenase. The procedure yields viable cells with highly preserved ultrastructural and metabolic features.