Yolk Sell

After being given a single oral dose of 40 muCi. of 109CdCl2, laying hens were fed a practical type ration to which 0 or 60 p.p.m. cadmium (Cd, as CdCl2) was added. On the basis of 109Cd in excrement, apparent absorption of the isotope averaged less than 10% of the dose for both diets. Less than 4% of the dose was retained in total body tissue 23 days after dosing. Dietary Cd level did not significantly influence excretion of 109Cd by hens, but hens fed 60 p.p.m. Cd retained a significantly higher proportion of 109Cd dose in liver, kidneys and whole body than did control hens...

The origin of yolk sac carcinoma obtained from rat embryos transplanted to extrauterine sites was traced to the extraembryonic portion of 9-day egg-cylinders. Under appropriate conditions cells of the extraembryonic portion of the egg cylinder differentiate into cells of parietal yolk sac epithelium, continue to proliferate and form retransplantable malignant tumors. Serum concentrations of alpha-fetoprotein were elevated in rats bearing yolk sac carcinomas and in some animals bearing teratomas admixed with yolk sac carcinoma...

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Eight-day rat egg cylinders transplanted in toto under the kidney capsules of adult histocompatible recipients gave rise to small nodules composed of parietal yolk sac cells surrounded by Reichert's membrane-like material. These yolk sac cells could grow and give rise to malignant, transplantable tumors identical to mouse yolk sac carcinomas derived from teratocarcinoma. The sera of rats with yolk sac tumors contained elevated concentrations of alpha1 fetoprotein.

The clinical pathological findings of eight cases of ovarian endodermal sinus tumour (yolk sac tumour) are presented. Histological exmination in all eight cases showed a typical endodermal sinus tumour pattern, and in six of the patients other tumour elements such as dysgerminoma, choriocarcinoma, malignant teratoma, endometriosis, and a dermoid cyst were also found. Six patients had increased serum alpha-fetoprotein concentration in the post-operative period, and two patients had a normal concentration 27 and 35 days after operation, respectively...

The expression of an "oncodevelopmental" protein, alpha-fetoprotein (AFP), has been systematically studied in rats during normal development and during regeneration of the liver by fetal rat hepatocytes in vitro, in rats bearing transplantable hepatomas, in rats fed chemical carcinogens, and in mice that spontaneously develop hematomas. AFP is a serum protein made normally during fetal and neonatal stages by liver and yolk sac cells. In newborn rats at approximately 4 weeks of age, the production of AFP is abruptly terminated, a process which is closely associated with cessation of liver cell proliferation...

The tissue sites of alpha1 fetoprotein (AFT) synthesis by the rat during gestation and hepatoma growth were determined by specific incorporation of a radiolabeled amino acid precursor into AFP by tissue cultures in vitro. During gestation, AFP were produced by the yolk sac, the fetal liver, and in small amounts by the fetal gastrointestinal tract; there was no synthesis by maternal rat tissues. During growth of a transplantable hepatoma, only the hepatoma tissue synthesized AFP; the nontumor tissue of the host contained AFP but did not produce it...