title: The in vitro maintenance of the limb-bud apical ridge by cell-free preparations.
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects*; D002457:Cell Extracts / Q000494:pharmacology*; D002474:Cell-Free System; D002642:Chick Embryo / Q000378:metabolism*; D003470:Culture Media; D004475:Ectoderm / Q000166:cytology / Q000502:physiology; D004627:Embryonic Induction / Q000187:drug effects*; D007552:Isotonic Solutions; D008264:Macrophages / Q000166:cytology; D008648:Mesoderm / Q000166:cytology / Q000502:physiology; D012462:Saline Solution, Hypertonic; D014020:Tissue Extracts / Q000494:pharmacology*; D014921:Wings, Animal / Q000196:embryology*
chemical_list: D002457:Cell Extracts; D003470:Culture Media; D007552:Isotonic Solutions; D012462:Saline Solution, Hypertonic; D014020:Tissue Extracts