title: Electron microscope autoradiographic studies of the erythroblasts of a case of congenital dyserythropoietic anaemia, type II.
abstract: The bone marrow cells of a patient with congenital dyserythropoietic anaemia, type II, were incubated with 3H-thymidine, 3H-uridine or 3H-leucine for 1 h and studied using the technique of electron microscope autoradiography. Several of the erythroblasts which either displayed the characteristic subsurface double membranes or showed various non-specific abnormalities of the nuclear membrane were found to be actively engaged in DNA, RNA and protein synthesis. Both members of some pairs of erythroblasts which were joined together by a spindle bridge were found to be engaged in DNA synthesis, indicating that some spindle bridges persist for a period longer than the duration of the G1 phase. A small proportion of mononucleate and binucleate late (non-dividing) erythroblasts showed a marked depression or arrest of protein synthesis and some or all of such cells were presumably destined to be phagocytosed by the bone marrow macrophages.
mesh_terms: D000740:Anemia / Q000151:congenital*; D001345:Autoradiography; D001854:Bone Marrow Cells; D002462:Cell Membrane / Q000648:ultrastructure; D002478:Cells, Cultured; D003593:Cytoplasm / Q000648:ultrastructure; D004247:DNA / Q000096:biosynthesis; D004900:Erythroblasts / Q000648:ultrastructure*; D004912:Erythrocytes / Q000648:ultrastructure*; D005260:Female; D006801:Humans; D008854:Microscopy, Electron; D009685:Nuclear Envelope / Q000648:ultrastructure; D014176:Protein Biosynthesis; D012313:RNA / Q000096:biosynthesis
chemical_list: D012313:RNA; D004247:DNA