title: Ontogeny of myelopoietic precursor cells in the chicken embryo.
abstract: The agar culture technique which enables enumeration of myeloid precursor cells was used to establish the time of appearance and further development of these cells in chick embryos. Yolk mesenchyme is the largest producer of precursor cells from day 6 to day 17 of incubation. In circulating blood precursor cells probably from the yolk appear at day 9 and stay at fairly high levels till day 17. Spleen and bone marrow have high percentage of precursor cells from day 10 till hatching, but afterwards rapid fall takes place to normal young adult levels. Thymus contains very few precursor cells during whole period of incubation. Bursa of Fabricius shows a very sharp peak of precursor activity on day 14 and 15 of incubation.
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells; D002060:Bursa of Fabricius / Q000166:cytology; D002478:Cells, Cultured; D002642:Chick Embryo; D002645:Chickens; D003115:Colony-Stimulating Factors; D003470:Culture Media; D006098:Granulocytes / Q000166:cytology*; D006410:Hematopoiesis; D007962:Leukocytes / Q000166:cytology*; D008264:Macrophages / Q000166:cytology*; D013154:Spleen / Q000166:cytology; D013950:Thymus Gland / Q000166:cytology; D015017:Yolk Sac / Q000166:cytology
chemical_list: D003115:Colony-Stimulating Factors; D003470:Culture Media