To review the data on the origins, phenotype, and function of embryonic phagocytes that has accumulated over past decade. Most of the relevant articles were selected based on the PubMed database entries. In additional, the Interactive Fly database (http://sdb.bio. purdue.edu/fly/aimain/1aahome.htm), FlyBase (http://flybase.bio. indiana.edu:82/), and TBase (http://tbase.jax.org/) were used to se...

For many years it has been assumed that the ontogeny of the mammalian hematopoietic system involves sequential transfers of hematopoietic stem cells (HSCs) generated in the yolk sac blood islands, to successive hematopoietic organs as these become active in the embryo (fetal liver, thymus, spleen and eventually bone marrow). Very little was known about early events related to hematopoiesis that...

The expression of calcitropic genes and proteins was localized within murine placenta during late gestation (the time frame of active calcium transfer) with an analysis of several gene-deletion mouse models by immunohistochemistry and in situ hybridization. Parathyroid hormone-related protein (PTHrP), the PTH/PTHrP receptor, calcium receptor, calbindin-D(9k), Ca(2+)-ATPase, and vitamin D recept...

A 45-year-old female patient presented with symptoms of polydipsia and polyuria, menopause, headache, gait disturbance and deteriorated mental state. Brain magnetic resonance imaging (MRI) showed an irregular mass in the anterior third ventricle. The tumor was excised using a transfrontal approach from the anterior section of the third ventricle. The histological diagnosis was of an intracrania...

The visceral yolk sac plays a critical role in normal embryogenesis, yet little is known about the specific molecules that regulate its development. We show here that four winged-helix genes (HNF-3alpha, HNF-3beta, HNF-3gamma and HFH-4) are restricted to visceral endoderm. In the absence of HNF-3beta, visceral endoderm forms but the morphogenetic movements by which the embryo becomes enclosed w...

Background: During the past 20 years a lot of information is achieved about the first trimester of pregnancy through ultrasound and intrauterine fertilization. Many researchers tried to use the symptoms of ultrasound in early pregnancy like measuring the gestational sac and yolk sac of the pregnancy to predict the continuation of pregnancy. Aim of the recent study is to predict the risk of spon...

A xenograft line, HX 53, has been established in immune-suppressed mice from a specimen of a lymph node metastasis in a patient with a histological diagnosis of seminoma but with markedly raised circulating levels of alpha-fetoprotein. Histological, immunocytochemical, and ultrastructural studies of this xenograft line have suggested that a solid variant of yolk sac carcinoma may exist, which m...

T H E placentation of Erinaceus europea has been described by Hubrecht (1889). An account of the development and structure of the avascular and vascular yolksac placentae which are formed in this species has been presented (Morris, 1953). Reichert's membrane is formed in the wall of the yolk-sac and it persists to term. A further study of the yolk-sac placentae, Reichert's membrane, the decidua...

The dominant hemoglobin of the adult hamster was detected in yolk-sac erythroid cells, and its identity was confirmed by peptide mapping and by analysis of relevant peptides. Both the presence and active synthesis of two embryonic hemoglobins presumed to exist only in yolk-sac erythroid cells were detected in neonatal liver and spleen. Thus the time span of expression of both embryonic and adul...

The possible relationship among malignancy, differentiation, and chro mosomal constitution of primary embryo-derived tumors was studied. Tumors were induced by transplanting 7-day-oId mouse embryos under the kidney capsule of syngeneic BALB/c recipients. Transplantation of 101 embryos resulted in 81 tumor-bearing mice: 36 teratocarcinomas; 18 teratomas; and 27 yolk sac tumors. Some of the yolk ...