title: Megakaryocytes separation in homogeneous classes by unit gravity sedimentation: physico-chemical, ultrastructural and cytophotometric characterizations.
abstract: Separation by velocity sedimentation at unit gravity according to the STAPUT system of Miller and Phillips was applied to a population of rabbit megakaryocytes previously enriched by density gradient centrifugation. By this means, 80,000 to 100,000 megakaryocytes with 100% purity were collected in eight fractions according to size for a sedimentation velocity of 52 to 30 mm/hr. DNA-Feulgen cytophotometric measurements show significant correlation between megakaryocyte size and ploidy. The study of the eight purified fractions is of particular interest because it reflects megakaryopoiesis evolution. The different stages of megakaryocyte maturation of each fraction were analysed by transmission and scanning electron microscopy and were correlated to ploidy level. Thrombopoietic megakaryocytes with grape-like appearance were found in ploidy fractions 8n to 128n. Cytophotometric determinations of nucleohistones revealed several populations.
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000378:metabolism; D002469:Cell Separation / Q000379:methods; D006651:Histocytochemistry; D008533:Megakaryocytes / Q000145:classification* / Q000378:metabolism / Q000648:ultrastructure; D011003:Ploidies; D011817:Rabbits