The yolk sac membrane plays a major role in the transport of nutrients from the yolk contents to the chick embryo. We examined whether the yolk sac membrane expresses genes for nutrient digestion, enzymes, and nutrient transporters. We evaluated relative mRNA abundance of the digestive enzymes aminopeptidase N (APN) and sucrase-isomaltase (SI); the nutrient transporters oligopeptide transporter...

Calcium, magnesium, copper, iron and zinc are stored in hens’ egg yolk and, except for copper, the majority of these minerals are located in egg yolk granules (Table 1). Presumably, up to 90% calcium, magnesium, iron and zinc are firmly bound in the phosvitin-lipovitellin complex of granules (GREENGARD et al., 1964; TABORSKY, 1980; TUPPER et al., 1954). As was discussed by Richards, copper ions...

Hematopoiesis is the developmentally regulated and tissue-specific process of blood cell production. The predominant anatomic site of hematopoiesis changes several times during murine and human ontogeny. Blood and endothelial cells become morphologically identifiable on embryonic day 7.5 (E7.5) in the developing murine yolk sac blood islands.1 Upon initiation of blood flow through the systemic ...

Background: To evaluate the role of 3D, 4D and color Doppler ultrasound (US) in the assessment of early human development. Materials and Methods: 380 women with uncomplicated early pregnancy between 5 and 14 weeks were evaluated by 3D, 4D and color Doppler US. Results: Regression analysis revealed exponential rise of the gestational sac volume with gestational age throughout the first trimester...

To reveal differentiation potency of yolk-sac endoderm, this tissue from quail embryos was cultured alone or in association with digestive-tract mesenchymes of chick embryos. When yolk-sac endoderm was cultured alone in vitro, the endoderm of the area vitellina differentiated into the yolk-sac parenchyma, but the endoderm of the extraembryonic area pellucida (EEAP) failed to differentiate into ...

Our goals were to determine the prognostic value of a yolk sac or fetal heart motion seen during an early accurately dated transvaginal ultrasound (TVU). We reviewed 225 consecutive pregnancies for fetal heart motion data. Furthermore, 63 pregnancies following in-vitro fertilization were reviewed for yolk sac information. The TVU was performed between 5 and 6 weeks following presumed conception...

In the adult, platelets are derived from unipotential megakaryocyte colony-forming cells (Meg-CFCs) that arise from bipotential megakaryocyte/erythroid progenitors (MEPs). To better define the developmental origin of the megakaryocyte lineage, several aspects of megakaryopoiesis, including progenitors, maturing megakaryocytes, and circulating platelets, were examined in the murine embryo. We fo...

BACKGROUND Malignant germ cell tumours are the most common malignant tumours in young men. They are histologically divided into seminomas and non-seminomas. Non-seminomas are further subdivided into embryonic carcinomas, yolk sac tumours, chorionic carcinomas, and teratomas. For the therapeutic management it is essential to differentiate between these histological subtypes. METHODS Investigat...

The present study aims at investigating muscle development and stress response in early stages of Siberian sturgeon when subjected to different rearing temperatures, by analysing growth and development of the muscle and by assessing the stress response of yolk-sac larvae. Siberian sturgeon larvae were reared at 16°C, 19°C and 22°C until the yolk-sac was completely absorbed. Sampling timepoints ...