title: Histochemical study of the definitive erythropoietic foci in the chicken yolk sac.
abstract: It is well known that avian yolk sac is involved in both primitive and definitive erythropoiesis during embryonic development. Definitive erythropoiesis is first detected at about 4-5 days incubation and its maximum activity is reached between day 10 and 15 of incubation, ending between days 18 and 20 of incubation. We confirmed the definitive erythropoietic foci in the chicken yolk sac throughout the 5th to 19th day of incubation by histochemical light and electron microscopy. The definitive erythropoietic foci were observed in the yolk sac endodermal layer from day 5 until day 19, just before hatching. Ultrastructurally, definitive erythropoietic foci were observed extravascularly in the yolk sac endodermal cell layer in direct contact with the vitellolysis zone. These findings provide a basis for clarifying definitive erythropoiesis in vertebrates.
authors.affiliation: Laboratory of Electron Microscopy, School of Medicine, Fujita Health University, Toyoake, Aichi, Japan. g-niimi@fujita-hu.ac.jp
authors.forename: Gen
authors.initials: G
authors.lastname: Niimi
authors.forename: Nobuteru
authors.initials: N
authors.lastname: Usuda
authors.forename: Masanori
authors.initials: M
authors.lastname: Shinzato
authors.forename: Chiyuki
authors.initials: C
authors.lastname: Kaneko
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Nagamura
authors.forename: Jaime
authors.initials: J
authors.lastname: Pereda
mesh_terms: D000818:Animals; D001808:Blood Vessels / Q000196:embryology / Q000648:ultrastructure; D002642:Chick Embryo; D004396:Coloring Agents; D004527:Egg Proteins / Q000378:metabolism; D004707:Endoderm / Q000648:ultrastructure; D004912:Erythrocytes / Q000648:ultrastructure*; D015672:Erythroid Precursor Cells / Q000648:ultrastructure*; D004920:Erythropoiesis; D006651:Histocytochemistry; D008833:Microcirculation / Q000196:embryology / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D018919:Neovascularization, Physiologic; D015017:Yolk Sac / Q000098:blood supply* / Q000196:embryology* / Q000648:ultrastructure
chemical_list: D004396:Coloring Agents; D004527:Egg Proteins