An electron microscope study of the intercellular contacts between the erythroblasts of patients with hypersiderotic bone marrows.

When stained and unstained sections of hypersiderotic marrow fragments are examined in the electron microscope, some of the ferritin molecules present between a variable proportion of the erythroblasts are found to be aligned more or less transversely. These linearly arranged ferritin molecules are particularly evident in regions in which the opposing cell membranes have been sectioned obliquely and may be confused with the septa-containing intercellular junctions characteristically present between some types of invertebrate epithelial cells.