Human Bone Marrow Chromosomes in Megaloblastic Anemia By EDWARD R. POWSNER AND LAWRENCE BERMAN

T HE PROFOUND alteration in human erythrobbasts in folic acid or vita-mm B12 deficiency is manifest to an important degree by the appearance of the interphase nuclear chromatin in the megaloblastic cells. This is re-flected in the appearance of the individual chromosomes, and it is generally agreed that the chromosomes of megaloblasts differ in morphologic details from those of normoblasts. Rohrt refers to the chromosomes in megaloblasts as more delicate and slender than those in normoblasts, and Fieschi2 and Kienbe3 have made similar observations. Kiossogbou and Mitus mention “giant” chromosomes in their list of chromosomal abnormalities observed in pernicious anemia.4 Our own experience with Giemsa-, Wright- or Leishman-stained dry films confirms this impression. It seems probable that the alterations in the morphologic appearances of the individual chromosomes are related to struc-tural changes, such as the degree of coiling. These phenomena may in turn be related to the presence of abnormal biochemical end-products or a deficiency of normal substances that are intimately associated with maintaining th